Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/16/14
AREA FORECAST DISCUSSION
NWS TUCSON AZ
850 PM MST FRI AUG 15 2014
.SYNOPSIS...THUNDERSTORM CHANCES REMAIN IN THE FORECAST INTO EARLY
NEXT WEEK. SOME STORMS WILL PRODUCE HEAVY RAIN THAT MAY LEAD TO
FLOODING.
&&
.DISCUSSION...AFTER A SOMEWHAT ACTIVE EVENING ONLY A FEW WEAK
ECHOES REMAIN ON THE KEMX RADAR...MAINLY ACROSS SANTA CRUZ AND
COCHISE COUNTIES. CONSIDERABLE DEBRIS CLOUDINESS WAS EVIDENT ON IR
SATELLITE IMAGERY AT 03Z ACROSS THESE SAME AREAS WITH THE COOLEST
CLOUD TOPS OVER PIMA/SANTA CRUZ COUNTIES NEAR THE INTERNATIONAL
BORDER...WHERE THE MOST INTENSE CONVECTION HAS JUST RECENTLY MOVED
SOUTH INTO MEXICO. SFC TEMPS THIS EVENING RANGED FROM THE UPPER 60S
TO UPPER 80S WITH DEWPOINTS SITTING MAINLY IN THE 50S AND 60S AREA
WIDE. CURRENT TRENDS SUGGEST WE SHOULD BE DONE WITH PRECIP FOR THE
EVENING...HOWEVER THERE CONTINUES TO BE CONVECTION JUST OVER THE
BORDER IN NRN SONORA MEXICO. LATEST HRRR HAS PRECIP ENDING AREA WIDE
AFTER 06Z ALTHOUGH CANNOT COMPLETELY RULE OUT A SHOWER NEAR EITHER
THE AZ/NM OR INTERNATIONAL BORDER TONIGHT...SO WILL LEAVE INHERITED
POPS AS THEY ARE WITH CHC AND SLIGHT CHC POPS IN THOSE LOCATIONS
AFTER 06Z. FORECAST LOOKS TO BE ON TRACK TONIGHT...NO UPDATES ARE
PLANNED. PLEASE SEE THE PREVIOUS DISCUSSION BELOW FOR MORE
INFORMATION.
&&
.AVIATION...VALID THRU 17/06Z. SCATTERED -SHRA AND ISOLD -TSRA WILL
PREVAIL LATE TONIGHT INTO SATURDAY MORNING. THEN SCATTERED AFTERNOON
-TSRA/-SHRA SATURDAY AFTERNOON/EVENING MAINLY EAST OF KTUS. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...DAILY SCATTERED AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS ARE EXPECTED THIS WEEKEND. STRONG...GUSTY AND ERRATIC
WINDS BETWEEN 35 AND 45 MPH ARE POSSIBLE WITH STRONGER
THUNDERSTORMS. OTHERWISE...WINDS WILL SHOW NORMAL DIURNAL TRENDS AND
BE LESS THAN 15 MPH.
&&
.PREV DISCUSSION...N TO NE MID UPPER FLOW WILL TEND TO LOWER
PRECIPITABLE WATER VALUES THIS WEEKEND...BUT EVER SO
SLIGHTLY...BEFORE BETTER MOISTURE SEEPS BACK INTO THE AREA EARLY
NEXT WEEK. THUNDERSTORM FORECAST GENERALLY REFLECTS A SLIGHT
DOWNTURN THIS WEEKEND FOLLOWED BY AN UPTICK EARLY NEXT
WEEK...ALTHOUGH AREAS TO THE SE WILL MAINTAIN A DECENT CHANCE FOR
RAIN THE ENTIRE FORECAST PERIOD.
HIGH TEMPERATURES WILL RANGE FROM SLIGHTLY ABOVE NORMAL NW TO
SLIGHTLY BELOW NORMAL SE.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
DISCUSSION...FRENCH
PREV DISCUSSION...DROZD
AVIATION/FIRE WEATHER...BROST
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
323 PM MDT THU AUG 14 2014
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 323 PM MDT THU AUG 14 2014
WEATHER IS BEHAVING ABOUT AS EXPECTED THIS AFTERNOON. A FEW HEAVY
RAINERS HAVE DUMPED AROUND AN INCH IN SPOTS BUT NO MAJOR ISSUES
AS OF YET. THIS HEAVY RAIN THREAT WILL CONTINUE INTO THE EARLY
EVENING HOURS. MAIN LINE OF ACTIVITY IS JUST COMING OFF THE
FOOTHILLS AT 2030Z AND SHOULD SPREAD EAST ACROSS THE PLAINS OVER
THE NEXT SEVERAL HOURS. HRRR HAS ACTIVITY ENDING AROUND MIDNIGHT.
UPPER TROUGH IS OVER THE MOUNTAINS RIGHT NOW WITH QUASIGEOSTROPHIC
ASCENT HELPING THINGS OUT AHEAD OF IT AND TENDING TO SQUASH MOST
BUT NOT ALL CONVECTION OVER WESTERN COLORADO. THIS SUBSIDENCE WILL
BECOME MORE PREVALENT OVERNIGHT ACROSS THE AREA AND STRENGTHEN
TOMORROW. THIS SHOULD CLEAR TONIGHT /PER CIRA SYNTHETIC SATELLITE
IMAGERY/ AND WILL COUPLE WITH LESS MOISTURE AND LOW-LEVEL
DOWNSLOPE FLOW EAST OF THE MOUNTAINS TO LESSEN THE CONVECTIVE
ACTIVITY FRIDAY AFTERNOON. WITH LESS SHOWER/THUNDERSTORM/CLOUDS
MINIMUM TEMPERATURES SHOULD BE LOWER TONIGHT WITH MAXIMA TOMORROW
A FEW DEGREES WARMER.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 323 PM MDT THU AUG 14 2014
UPPER RIDGING WILL BUILD OVER COLORADO AND THE WESTERN U.S.
THROUGH THE WEEKEND...BRINGING AN EVENTUAL DECREASE IN AFTERNOON
AND EVENING THUNDERSTORM ACTIVITY. MOISTURE WILL LINGER OVER THE
REGION WHICH WILL BE AVAILABLE TO FUEL DIURNAL THUNDERSTORM
ACTVITIY EACH DAY...BUT RISING HEIGHTS MAY ALSO PRODUCE MID-LEVEL
INVERSIONS THAT CAP OFF CONVECTIVE DEVELOPMENT. FOR THE TIME BEING
WILL STICK WITH POPS IN THE 20-30 PERCENT RANGE...PRIMARILY OVER
THE MOUNTAINS AND FOOTHILLS. BY EARLY NEXT WEEK...BUILDING HIGH
PRESSURE OFF THE OREGON COAST WILL LEAVE COLORADO UNDER A WEAK
AND PERSISTENT NORTHWESTERLY FLOW ALOFT. THE GENERAL PATTERN
ACROSS THE COUNTRY WILL BE LOW AMPLITUDE AND PROGRESSIVE. THIS
SHOULD KEEP TEMPERATURES AROUND SEASONAL NORMALS AND PRECLUDE THE
ACCUMULATION OF EXCESSIVE MOISTURE OVER THE STATE. THE MIDDLE OF
NEXT WEEK MAY BE ENTIRELY DRY...BUT THE ABSENCE OF STRONGER
RIDGING IN THE MODEL SOLUTIONS WILL KEEP ME FROM PULLING AFTERNOON
THUNDERSTORMS OUT OF THE FORECAST.
&&
.AVIATION...(FOR THE TAFS THROUGH 00Z FRIDAY LATE AFTERNOON)
ISSUED AT 323 PM MDT THU AUG 14 2014
CONVECTION COMING OFF THE HILLS WILL BRING ISSUES TO ALL TERMINALS
THROUGH AROUND 00Z OR SO WITH ACTIVITY EAST OF THE METRO AREA BY
THEN. WINDS WILL BE MESSY AS IT PASSES BUT WE MAY STILL BE ABLE TO
GET A MORE GENERAL WESTERLY FLOW FOR A COUPLE OF HOURS AFTER THE
LINE PASSES. THIS WILL THEN TRANSITION TO DRAINAGE LATER IN THE
EVENING. SOME HINT OF NORTHWESTERLIES IN THE 10-15 KNOT RANGE
TOMORROW AFTERNOON BEHIND TODAY/S SYSTEM.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...ET
LONG TERM...DANKERS
AVIATION...ET
AREA FORECAST DISCUSSION
NWS PUEBLO CO
310 PM MDT THU AUG 14 2014
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 310 PM MDT THU AUG 14 2014
...FLASH FLOOD POTENTIAL TO CONTINUE THROUGH THIS EVENING FOR THE
CONTINENTAL DIVIDE AND PIKES PEAK REGION...
SHORTWAVE CURRENTLY MOVING ACROSS NORTHERN CO HAS INITIATED
THUNDERSTORMS OVER THE PIKES PEAK REGION THIS AFTERNOON. HIGH
PRECIPITABLE WATERS RUNNING 150+% OF NORMAL IS ALLOWING FOR
EFFICIENT RAINFALL RATES AS EVIDENCED FROM RADAR KDP/S AND SPOTTER
REPORTS. THERE HAVE ALSO BEEN SOME PEA SIZE HAIL REPORTS WITH THE
STRONGER STORMS. AS THE SHORTWAVE CONTINUES TO DRAG ACROSS EASTERN
COLORADO...THUNDERSTORMS WILL CONTINUE TO SPREAD EASTWARD ACROSS THE
PLAINS. STORMS HAVE BEEN MOVING NORTHEAST AT 15 MPH...ENOUGH TO
ABATE SOME OF THE FLASH FLOOD RISK...BUT NOT ENTIRELY NEGATE IT AS
HEAVY RAINFALL RATES OF AROUND 2 INCHES PER HOUR CAN STILL CAUSE
PROBLEMS FOR THE BURN SCARS AND URBAN AREAS. THUS WILL KEEP THE
FLASH FLOOD WATCH GOING THROUGH 9 PM. BEEN A LITTLE HARDER TO GET
STRONGER CONVECTION GOING OUT WEST ALONG THE CONTINENTAL DIVIDE AND
SUSPECT THAT THREAT THERE IS RAPIDLY DIMINISHING AS STABILITY HAS
BEEN A FACTOR WITH THE CLOUD COVER AND EARLIER RAINFALL. WILL KEEP
THE WATCH GOING THROUGH THE PRIME HEATING HOURS...BUT SUSPECT THAT
WE MAY BE ABLE TO TAKE DOWN THE WATCH BY 6 PM FOR CHAFFEE/LAKE
COUNTIES AND THE EASTERN SAN JUANS AND LA GARITAS.
THUNDERSTORMS WILL SPREAD EASTWARD ACROSS THE PLAINS THROUGH THE
EVENING HOURS. LATEST HRRR SUGGESTS THAT THREAT FOR PIKES PEAK AREA
MAY BE ENDED BY 6-7 PM. HIGHEST POPS THROUGH THE EVENING HOURS WILL
BE ACROSS THE SOUTHEAST PLAINS AS THUNDERSTORMS DEVELOP ALONG
SOUTHWARD ADVANCING COLD FRONT. APPEARS BEST LIFT MAY BE ACROSS
NORTHWEST KANSAS AND EAST CENTRAL CO (KIOWA COUNTY) AS LOW LEVEL JET
IMPINGES ON THE FRONT...SO WILL KEEP HIGHEST POPS UP THAT WAY. MOST
OF THE ACTIVITY WILL BE DONE BY MIDNIGHT AS LINE OF THUNDERSTORMS
MOVES EAST INTO KANSAS.
A LITTLE LESS ACTIVE WEATHER IS EXPECTED TOMORROW. PRECIPITABLE
WATERS WILL DROP OFF BELOW 1 INCH FOR THE I-25 CORRIDOR AND
WESTWARD. STILL LOOKING AT SUFFICIENT MOISTURE FOR ISOLATED TO
SCATTERED THUNDERSTORMS...SO STILL CAN`T RULE OUT HEAVY RAIN ON BURN
SCARS AND POTENTIAL FOR FLASH FLOODING. BUT THREAT CERTAINLY LOOKS
LOWER DUE TO THE MORE ISOLATED NATURE OF THESE STRONGER CELLS.
GRIDS WILL CARRY MORE OF A DIURNAL POP TREND...WITH THUNDERSTORMS
FIRING OVER THE MOUNTAINS AROUND NOON...THEN DEVELOPING/SPREADING
EASTWARD ACROSS THE ADJACENT PLAINS DURING THE LATE AFTERNOON. -KT
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 310 PM MDT THU AUG 14 2014
FRIDAY NIGHT-THURSDAY...NOT MUCH CHANGE IN THE ONGOING FORECAST
THROUGH THE EXTENDED PERIOD WITH FLAT UPPER LEVEL RIDGING REMAINING
IN PLACE ACROSS THE GREAT BASIN THROUGH THE ROCKIES. THIS WILL KEEP
MONSOONAL MOISTURE PLUME SOUTH AND SOUTHWEST OF THE STATE WITH WEAK
WEST TO NORTHWEST FLOW ALOFT ACROSS THE STATE AND WEATHER SYSTEMS
MOVING ACROSS THE NORTHERN TIER OF STATES AND INTO THE UPPER
MIDWEST.
THERE LOOKS TO BE ENOUGH RESIDUAL MOISTURE IN PLACE TO WORK WITH
LATE SUMMER SOLAR HEATING TO KEEP ISOLATED TO SCATTERED AFTERNOON
AND EVENING STORMS IN THE FORECAST OVER AND NEAR THE HIGHER
TERRAIN...WITH A FEW STORMS POSSIBLY ROLLING ACROSS THE FAR SE
PLAINS THROUGH THE LATE EVENING AND OVERNIGHT HOURS. STORMS THAT DO
DEVELOP SHOULD BE GENERALLY HIGH BASED...THOUGH STILL CAN NOT RULE
OUT LOCALIZED HEAVY RAINFALL AND SMALL HAIL WITH STRONGER CELLS.
HARD TO PIN POINT BEST COVERAGE OF STORMS THOUGH COULD SEE INCREASED
COVERAGE SUNDAY THROUGH SUNDAY NIGHT AND AGAIN TUESDAY AND TUESDAY
NIGHT AS EMBEDDED DISTURBANCES MOVE ACROSS THE NORTHERN ROCKIES AND
INTO THE HIGH PLAINS. WITH RIDGING IN PLACE...TEMPERATURES ACROSS
THE AREA LOOK TO BE GENERALLY AT OR SLIGHTLY ABOVE LATE SUMMER
AVERAGES THROUGH THE PERIOD.
THERE COULD BE A CHANGE IN THE PATTERN INTO EARLY NEXT WEEKEND...AS
A BROAD UPPER TROUGH TRIES TO CARVE OUT ACROSS THE WEST COAST
OPENING THE DOOR TO INCREASING MOISTURE WITHIN DEVELOPING SOUTH TO
SOUTHWEST FLOW ALOFT ACROSS THE DESERT SOUTHWEST AND INTO THE
ROCKIES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 310 PM MDT THU AUG 14 2014
THUNDERSTORMS WILL CONTINUE THROUGH THROUGH THE EVENING HOURS FOR
THE MOUNTAINS AND I-25 CORRIDOR WITH THREAT FOR TSRA AT TERMINALS TO
CONTINUE UNTIL 00-01Z. CIGS COULD DROP INTO THE MVFR TO EVEN BRIEF
IFR CATEGORY UNDER THE STRONGER STORMS WITH HEAVY RAIN AND PEA SIZE
HAIL POSSIBLE. THUNDERSTORMS WILL END FROM WEST TO EAST AT THE
TERMINALS THROUGH THE EVENING WITH VFR CONDITIONS EXPECTED
OVERNIGHT. THREAT FOR THUNDERSTORMS WILL BE LESS TOMORROW AND
MAINLY CONFINED TO THE MOUNTAIN AREAS THOUGH THE AFTERNOON...THOUGH
A FEW MAY DRIFT INTO THE SOUTHEAST PLAINS DURING THE EVENING. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 9 PM MDT THIS EVENING FOR COZ058>068-081-
082-084-085.
&&
$$
SHORT TERM...KT
LONG TERM...MW
AVIATION...KT/MW
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
950 AM MDT THU AUG 14 2014
.UPDATE...
ISSUED AT 950 AM MDT THU AUG 14 2014
A COUPLE OF OPPOSING FORCES WILL IMPACT THINGS TODAY. FIRST ON THE
SYNOPTIC SCALE LATEST RAP ANALYSES SHOW SLOWLY INCREASING
QUASIGEOSTROPHIC SUBSIDENCE BEGINNING TO OVERSPREAD WESTERN
COLORADO. THIS MODEL AS WELL AS OTHERS SHOW THIS INCREASING TREND
IN BOTH STRENGTH AND AREAL COVERAGE OF THE SUBSIDENCE THROUGHOUT
THE DAY AND INTO THIS EVENING. IN ADDITION LOW LEVEL HEIGHT FALLS
TO OUR EAST ARE PRODUCING DOWNSLOPE FLOW EAST OF THE MOUNTAINS.
NEITHER OF THESE PHENOMENA BODE WELL FOR AIDING CONVECTIVE
ACTIVITY. ON THE OTHER HAND PRECIPITABLE WATER VALUES ARE
SUBSTANTIAL...1.40 CURRENTLY AT GJT WITH 1.10 AT BOULDER.
ADDITIONALLY THERE IS AN ONGOING AREA OF CONVECTION APPROACHING
THE CONTINENTAL DIVIDE AND SOME HOLES SHOWING UP IN THE MIDLEVEL
CLOUD DECK. BOTH OF THESE ARE GOOD SIGNS OF COURSE. WHICH IS GOING
TO WIN OUT IS STILL IN QUESTION BUT THE PRESENT FORECAST SEEMS
REASONABLE CONSIDERING ALL OF THE ABOVE FACTORS. CONSEQUENTLY
THERE ARE NO CHANGES PLANNED AT THIS TIME.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 400 AM MDT THU AUG 14 2014
FORECAST ON TRACK WITH TRENDS OF HIGHER CHANCES OF SHOWERS AND
COOLER TEMPERATURES TODAY OVER THE FRONT RANGE AND NORTHEAST
PLAINS. WATER VAPOR IMAGERY SHOWING THE RIDGE ALOFT SHIFTING EAST
INTO THE CENTRAL PLAINS WHILE A WEAK WAVE ALOFT NOW LIFTING
NORTHEAST OVER WESTERN COLORADO AND EASTERN UTAH. RADAR IMAGERY
SHOWING GOOD COVERAGE OF SHOWERS OVER WESTERN COLORADO AND THIS
SWATH OF SHOWERS WILL GRADUALLY SHIFT EAST OVER BOU CWA MOUNTAINS
DURING THE MORNING HOURS. INTEGRATED PW VALUES FROM GPS SHOWING
SUBSTANTIAL INCREASE OF AROUND A THIRD OF AN INCH IN THE PAST
18 HRS AND VALUES ARE NOW OVER AN INCH OF PRECIPITABLE WATER.
DESPITE THE INCREASE IN MOISTURE LEVELS...THE INSTABILITY IS NOT
ALL THAT GREAT TODAY GIVEN CONSIDERABLE CLOUD COVER AHEAD OF THE
WAVE. THIS WILL RESULT IN COOLER AFTERNOON TEMPERATURES AND LESS
INSTABILITY WITH SURFACE BASED CAPES LESS THAN 500J/KG OVER THE
FRONT RANGE. SOMEWHAT BETTER INSTABILITY OVER THE FAR NORTHEAST
PLAINS GIVEN HIGHER DEWPOINTS IN THE LOWER 60S AND POTENTIAL
HIGHER CAPES UP AROUND 1000J/KG. EXPECT HEAVY RAIN AND GUSTY
WINDS WITH THE SHOWERS AND STORMS TODAY. GIVEN STORM MOTIONS OF
10-15KT EXPECT OVERALL FLASH FLOOD THREAT ON THE LOW SIDE DESPITE
THE HIGH MOISTURE VALUES. BURN SCARS WILL HAVE THE HIGHEST IMPACT
FOR FLOOD POTENTIAL BUT NOT WIDE SPREAD ENOUGH TO ISSUE ANY FLASH
FLOOD WATCHES. BASED ON LATEST MODEL CONSENSUS MOST OF THE STORMS
MAY BE DONE OVER THE MOUNTAINS/ADJ PLAINS AROUND 00Z AND THEN
ENDING OVER THE PLAINS BY MIDNIGHT. WILL MAKE SOME ADJUSTMENTS FOR
FASTER ENDING OF STORMS DURING THE EVENING FROM WEST TO EAST.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 400 AM MDT THU AUG 14 2014
THE SHORTWAVE TROUGH PASSING OVER THE FCST AREA TODAY WILL HAVE
MOVED EAST OF THE STATE BY EARLY ON FRIDAY AS THE UPPER RIDGE
REGAINS ITS HOLD ON THE FOUR CORNERS REGION. WITH THE CORE OF THE
UPPER RIDGE IN THIS POSITION THE RECENT NORTHWARD INTRUSION OF
MONSOON MOISTURE WILL SHUT OFF...LEADING TO DRIER AND WARMER
CONDITIONS ACROSS THE FORECAST AREA FOR FRIDAY AND SATURDAY. HOWEVER
THERE SHOULD BE SUFFICIENT MID-LEVEL MOISTURE AROUND TOGETHER WITH
STG SOLAR HEATING TO GENERATE ISOLATED TO SCATTERED T-STORMS OVER
AND NEAR THE FRONT RANGE MTNS BOTH DAYS. AND WITH THE RIDGE AXIS
SITTING OVER THE UTAH/COLORADO LINE...THE LIGHT FLOW ALOFT WILL BE
NWLY. IN THE PRESENCE OF A LOW CAPE ENVIRONMENT...THE FEW HIGH-
BASED STORMS THAT MANAGE TO DRIFT SEWRD OFF THE FRONT RANGE SHOULD
QUICKLY COLLAPSE BEFORE VENTURING TOO FAR OUT ONTO THE PLAINS.
NEAR AVERAGE TEMPERATURES ARE FCST FOR BOTH DAYS.
FOR THE PERIOD SUNDAY-MONDAY...MODELS SHOW TO UPPER RIDGE CONTINUING
ITS SLOW WESTWARD MIGRATION OVER THE GREAT BASIN AND DESERT
SOUTHWEST AS A MORE ORGANIZED SHORTWAVE TROUGH TRACKS EWRD ACROSS
MONTANA AND WYOMING ON SUNDAY...AND ACROSS THE NORTHERN GREAT
PLAINS ON MONDAY. MODELS SHOW THE SOUTHERN TIP OF THIS TROUGH
BRUSHING NERN COLORADO LATE ON SUNDAY...WITH POSSIBLY ANOTHER
GLANCE OF THIS EXITING TROUGH ON MONDAY. THIS SECOND BRUSH WITH
THE TROUGH MAY INCLUDE A WEAK COLD FRONT WHICH MODELS SHOW
BACKING THRU NERN COLORADO DURING THE MORNING HOURS. DO NOT EXPECT
MUCH COOLING WITH ITS ARRIVAL...BUT THE LIGHT...SLIGHTLY MORE
MOIST E-NELY UPSLOPE FLOW BEHIND THE FRONT WILL HELP PRODUCE
ISOLATED LATE DAY T-STORMS OVER AND NEAR THE FRONT RANGE.
DURING THE TUESDAY-WEDNESDAY TIME FRAME...THE AIRMASS OVER NERN
COLORADO TURNS DRIER AS THE UPPER RIDGE OUT WEST FLATTENS AS YET
ANOTHER MORE POTENT UPPER TROUGH TRACKS EAST ALONG THE NWRN
U.S./SWRN CANADA BORDER. THIS PLACES COLORADO UNDER ZONAL FLOW
RESULTING IN LITTLE DAY-TO-DAY CHANGE IN TEMPERATURE.
&&
.AVIATION...(FOR THE TAFS THROUGH 18Z FRIDAY MORNING)
ISSUED AT 950 AM MDT THU AUG 14 2014
CURRENT TAFS APPEAR IN ORDER AND DO NOT FORESEE ANY BIG CHANGES
NEEDED WITH THE 18Z ISSUANCE.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...ET
SHORT TERM...ENTREKIN
LONG TERM...BAKER
AVIATION...ET
AREA FORECAST DISCUSSION...UPDATED
NWS MIAMI FL
807 PM EDT FRI AUG 15 2014
AVIATION...54/BNB
THERE COULD STILL BE A FEW SHOWERS OVER THE EAST COAST TAF SITES
UNTIL 02Z TONIGHT BEFORE GOING DRY THROUGH REST OF THE NIGHT. THE
SHOWERS WILL THEN RETURN TO THE EAST COAST TAF SITES AFTER 13Z ON
SATURDAY...BEFORE THUNDERSTORMS RETURN AFTER 19Z SATURDAY. SO WILL
KEEP VCSH UNTIL 02Z THEN DRY UNTIL 13Z SATURDAY FOR THE EAST COAST
TAF SITES. THE VCSH WILL THEN RETURN TO THE EAST COAST TAF SITES
FROM 13Z UNTIL 19Z SATURDAY BEFORE VCTS AFTER 19Z. THE WINDS WILL
ALSO REMAIN LIGHT FROM THE SOUTHWEST TONIGHT...BEFORE INCREASING
TO AROUND 5 KNOTS SATURDAY MORNING FOR THE EAST COAST TAF SITES.
THE WINDS WILL THEN SWING TO A SOUTHEAST DIRECTION AFTER 19Z
SATURDAY...AS THE EAST COAST SEA BREEZE DEVELOPS AND PUSHES
INLAND.
FOR KAPF TAF SITE...THE VCTS WILL REMAIN IN PLACE UNTIL 02Z THEN
VCSH FOR REST OF THE NIGHT HOURS. THE VCSH WILL CONTINUE ON
SATURDAY FOR KAPF TAF SITE. THE WINDS WILL BE LIGHT AND VARIABLE
TONIGHT AT KAPF TAF SITE...BEFORE GOING SOUTHWEST AROUND 5 KNOTS
ON SATURDAY.
THE CEILING AND VIS WILL REMAIN IN VFR CONDITIONS TONIGHT INTO
SATURDAY FOR ALL OF THE TAF SITES...BUT COULD NEED A TEMPO GROUP
FOR POSSIBLE REDUCE VIS AND CEILING FOR KAPF TAF SITES TONIGHT IF
ANY SHOWERS WORKS INTO THE AREA.
&&
.AVIATION...54/BNB
.PREV DISCUSSION... /ISSUED 750 PM EDT FRI AUG 15 2014/
UPDATE...STRONG THUNDERSTORMS WITH TORRENTIAL RAINS AFFECTED THE
EAST COAST EARLIER, BUT HAS SINCE ENDED. ADDITIONAL ACTIVITY IS
NOW MOVING IN FROM THE WEST...WITH THE STRONGEST STORMS OVER THE
GULF WATERS. ADJUSTED POPS/WEATHER BASED ON THESE TRENDS. ACTIVITY
WILL SLOWLY WANE WITH THE LOSS OF HEATING. /GREGORIA
&&
PREV DISCUSSION... /ISSUED 313 PM EDT FRI AUG 15 2014/
DISCUSSION...
AS OF 1830Z...VERY ACTIVE CONVECTION ACROSS THE ATLANTIC COAST
AND THE ADJACENT ATLANTIC WATERS. VERY ACTIVE THUNDERSTORMS EXTEND
FROM NORTHEAST MIAMI DADE NORTHWARD THROUGH EASTERN BROWARD AND
PALM BEACH COUNTIES. THE LATEST HRRR MESO-SCALE MODEL GUIDANCE
WHICH INITIALIZED GENERALLY WELL ON THIS CONVECTION INDICATES
THIS ACTIVITY STARTING TO DISSIPATE AROUND 22Z. BUT AS ALWAYS WITH
EXISTING OUTFLOW BOUNDARIES ADDITIONAL CONVECTION COULD LINGER
INTO THE EARLY EVENING HOURS WITH THE CURRENT FORECAST INDICATING
ACTIVE CONVECTION WITH NUMEROUS SHOWERS/THUNDERSTORMS ACROSS THE
EASTERN HALF OF THE PENINSULA THROUGH 00Z THIS EVENING.
THE LATEST MODEL GUIDANCE INDICATES SOME RELATIVELY DRIER AIR
FORECAST TO MOVE NORTHWARD INTO THE FLORIDA STRAITS TONIGHT INTO
SATURDAY. HOWEVER...THE GUIDANCE INDICATES THAT IT MAY NOT MAKE IT
FAR ENOUGH NORTHWARD ON SATURDAY SUCH THAT LINGERING DEEP
MOISTURE OVER MOST OF THE PENINSULA AND ADJACENT WATERS COULD LEAD
TO ADDITIONAL AFTERNOON SHOWERS/THUNDERSTORMS ACROSS THE REGION
WITH THE SATURDAY FORECAST INDICATING THE GREATEST COVERAGE ACROSS
THE INTERIOR ALTHOUGH SCATTERED ACTIVITY IS FORECAST FOR THE GULF
AND ATLANTIC COAST METRO AREAS. BY SUNDAY THE GUIDANCE INDICATES
THAT THE DRIER AIR IS FORECAST TO CONTINUE MOVING NORTH WITH A
CONSIDERABLE REDUCTION ACROSS THE REGION IN SHOWERS/THUNDERSTORMS
WITH MAINLY THE INTERIOR REGIONS FORECAST TO HAVE SCATTERED
ACTIVITY.
THERE IS GUIDANCE SUGGESTING THAT SOME DUST ASSOCIATED WITH THE SAHARAN
AIR LAYER COULD ENTER THE REGION LATE SATURDAY INTO SUNDAY THEN
MOVE ACROSS THE REGION LATE SUNDAY AND PERSIST INTO EARLY NEXT
WEEK. SO THERE MAY BE NOTICEABLY HAZY SKIES SUNDAY INTO EARLY
NEXT WEEK.
MARINE...
LIGHT SOUTH TO SOUTHWEST WINDS ARE FORECAST ACROSS THE REGIONAL
WATERS TONIGHT THROUGH SATURDAY. BY SUNDAY WINDS ARE FORECAST TO
BECOME EAST TO SOUTHEAST WHILE REMAINING AROUND OR BELOW 10 KNOTS
AND PERSISTING INTO EARLY NEXT WEEK. REGIONAL SEAS ARE FORECAST TO
BE 2 FEET OR LESS THROUGH THE WEEKEND INTO AT LEAST EARLY NEXT
WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 75 90 78 91 / 60 50 20 20
FORT LAUDERDALE 77 91 80 91 / 40 50 20 20
MIAMI 75 91 79 91 / 40 40 10 20
NAPLES 77 90 78 91 / 80 30 10 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...57/DG
LONG TERM....60/BD
AREA FORECAST DISCUSSION
NWS MIAMI FL
750 PM EDT FRI AUG 15 2014
.UPDATE...STRONG THUNDERSTORMS WITH TORRENTIAL RAINS AFFECTED THE
EAST COAST EARLIER, BUT HAS SINCE ENDED. ADDITIONAL ACTIVITY IS
NOW MOVING IN FROM THE WEST...WITH THE STRONGEST STORMS OVER THE
GULF WATERS. ADJUSTED POPS/WEATHER BASED ON THESE TRENDS. ACTIVITY
WILL SLOWLY WANE WITH THE LOSS OF HEATING. /GREGORIA
&&
.PREV DISCUSSION... /ISSUED 313 PM EDT FRI AUG 15 2014/
DISCUSSION...
AS OF 1830Z...VERY ACTIVE CONVECTION ACROSS THE ATLANTIC COAST
AND THE ADJACENT ATLANTIC WATERS. VERY ACTIVE THUNDERSTORMS EXTEND
FROM NORTHEAST MIAMI DADE NORTHWARD THROUGH EASTERN BROWARD AND
PALM BEACH COUNTIES. THE LATEST HRRR MESO-SCALE MODEL GUIDANCE
WHICH INITIALIZED GENERALLY WELL ON THIS CONVECTION INDICATES
THIS ACTIVITY STARTING TO DISSIPATE AROUND 22Z. BUT AS ALWAYS WITH
EXISTING OUTFLOW BOUNDARIES ADDITIONAL CONVECTION COULD LINGER
INTO THE EARLY EVENING HOURS WITH THE CURRENT FORECAST INDICATING
ACTIVE CONVECTION WITH NUMEROUS SHOWERS/THUNDERSTORMS ACROSS THE
EASTERN HALF OF THE PENINSULA THROUGH 00Z THIS EVENING.
THE LATEST MODEL GUIDANCE INDICATES SOME RELATIVELY DRIER AIR
FORECAST TO MOVE NORTHWARD INTO THE FLORIDA STRAITS TONIGHT INTO
SATURDAY. HOWEVER...THE GUIDANCE INDICATES THAT IT MAY NOT MAKE IT
FAR ENOUGH NORTHWARD ON SATURDAY SUCH THAT LINGERING DEEP
MOISTURE OVER MOST OF THE PENINSULA AND ADJACENT WATERS COULD LEAD
TO ADDITIONAL AFTERNOON SHOWERS/THUNDERSTORMS ACROSS THE REGION
WITH THE SATURDAY FORECAST INDICATING THE GREATEST COVERAGE ACROSS
THE INTERIOR ALTHOUGH SCATTERED ACTIVITY IS FORECAST FOR THE GULF
AND ATLANTIC COAST METRO AREAS. BY SUNDAY THE GUIDANCE INDICATES
THAT THE DRIER AIR IS FORECAST TO CONTINUE MOVING NORTH WITH A
CONSIDERABLE REDUCTION ACROSS THE REGION IN SHOWERS/THUNDERSTORMS
WITH MAINLY THE INTERIOR REGIONS FORECAST TO HAVE SCATTERED
ACTIVITY.
THERE IS GUIDANCE SUGGESTING THAT SOME DUST ASSOCIATED WITH THE SAHARAN
AIR LAYER COULD ENTER THE REGION LATE SATURDAY INTO SUNDAY THEN
MOVE ACROSS THE REGION LATE SUNDAY AND PERSIST INTO EARLY NEXT
WEEK. SO THERE MAY BE NOTICEABLY HAZY SKIES SUNDAY INTO EARLY
NEXT WEEK.
MARINE...
LIGHT SOUTH TO SOUTHWEST WINDS ARE FORECAST ACROSS THE REGIONAL
WATERS TONIGHT THROUGH SATURDAY. BY SUNDAY WINDS ARE FORECAST TO
BECOME EAST TO SOUTHEAST WHILE REMAINING AROUND OR BELOW 10 KNOTS
AND PERSISTING INTO EARLY NEXT WEEK. REGIONAL SEAS ARE FORECAST TO
BE 2 FEET OR LESS THROUGH THE WEEKEND INTO AT LEAST EARLY NEXT
WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 75 90 78 91 / 60 50 20 20
FORT LAUDERDALE 77 91 80 91 / 40 50 20 20
MIAMI 75 91 79 91 / 40 40 10 20
NAPLES 77 90 78 91 / 80 30 10 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
910 AM EDT THU AUG 14 2014
.DISCUSSION...
CURRENT-THIS AFTERNOON...UPPER LEVEL TROUGHING OVER THE EASTERN
THIRD OF THE UNITED STATES KEEPS BOTH THE UPPER LEVEL AND SURFACE
RIDGES SOUTH OF CENTRAL FLORIDA. STATIONARY SURFACE FRONT STRETCHES
FROM AROUND SAVANNAH GEORGIA TO THE PENSACOLA FLORIDA AREA THEN
SOUTHWEST TO AROUND BROWNSVILLE TEXAS PER THE LATEST SURFACE FRONT
ANALYSIS. CONTINUED SOUTH TO SOUTHWEST LOW LEVEL FLOW WITH AN
AFTERNOON SOUTHEAST SEA BREEZE FROM CAPE CANAVERAL SOUTH DUE TO A
WEAKER PRESSURE GRADIENT THAN PAST DAYS. RADARS ALREADY DETECTING
SHOWERS AND STORMS IN THE EASTERN GULF OF MEXICO COMING ASHORE FROM
THE FLORIDA BIG BEND AREA TO MARCO ISLAND ON THE SOUTHWEST FLORIDA
COAST. THE SHOWERS COMING ASHORE FROM CEDAR KEY TO SARASOTA COULD
MAKE IT TO THE WESTERN PORTIONS OF LAKE ORANGE AND OSCEOLA COUNTIES
LATE MORNING. THE SHOWERS THEN TRACK ACROSS THE REST OF EAST CENTRAL
FLORIDA WITH LIGHTNING STORMS DEVELOPING BY EARLY AFTERNOON DUE TO
DAYTIME HEATING AND A VERY MOIST ATMOSPHERE AS INDICATED BY THE
TAMPA...CAPE CANAVERAL AND JACKSONVILLE MORNING SOUNDINGS ALL
SHOWING PRECIPITABLE WATER VALUES ABOVE 2 INCHES OF WATER.
MORNING ZONES UPDATE WILL LOOK AT ANY CHANGES NEEDED TO THE VARIOUS
WIND GRIDS.
PREVIOUS ZONES DISCUSSION
TODAY-TONIGHT...AS IT HAS BEEN FOR AROUND THE PAST WEEK...THERE
REMAINS VERY LITTLE CHANGE IN THE LARGER SYNOPTIC PATTERN IN PLACE
ACROSS THE STATE. DEEP TROUGH ACROSS THE NORTHEASTERN US KEEPS THE
ATLANTIC RIDGE AXIS SUPPRESSED TO OUR SOUTH...TODAY REMAINING SOUTH
OF THE STATE ACROSS THE FLORIDA STRAITS.
OVERALL GRADIENT LOOKS WEAKER TODAY LEADING TO LIGHTER
WEST-SOUTHWEST FLOW. THIS SHOULD ALLOW FOR SLIGHTLY FASTER...AND
MORE EXPANSIVE...DEVELOPMENT OF THE EAST COAST SEA BREEZE AND THIS
IS REFLECTED IN THE LOCAL HRRR AND WRF. EVEN THE GFS AND ECMWF HINT
AT A SEA BREEZE ALONG THE TREASURE COAST. HOWEVER STILL DON`T EXPECT
MUCH INLAND PENETRATION MUCH PAST THE IMMEDIATE COAST OR WEST SIDE
OF THE INDIAN RIVER LAGOON.
CENTRAL FLORIDA WILL BE MORE SOLIDLY UNDER THE INFLUENCE OF THE
LOW-MID LEVEL MOISTURE LEFT BEHIND BY THE SURFACE FRONT THAT DIED
OUT TO OUR NORTH EARLIER THIS WEEK. WHILE THIS SHOULD LEAD TO A
LITTLE BETTER COVERAGE...OVERALL CONVECTIVE EVOLUTION REMAINS
SIMILAR WITH STORMS ALONG THE WEST COAST SEA BREEZE PUSHING EAST
THROUGH THE AFTERNOON. ISOLATED SHOWERS AND STORMS WILL ALSO BE
POSSIBLE ALONG THE EAST COAST SEA BREEZE WHERE IT DOES DEVELOP
BEFORE THE EASTWARD MOVING CONVECTION REACHES IT. COVERAGE WILL
INCREASE THROUGH THE AFTERNOON DUE TO VARIOUS BOUNDARY COLLISIONS.
AS IN PREVIOUS LATE AFTERNOONS AND EVENINGS STORMS TO END AROUND
SUNSET...LOSS OF DAYTIME HEATING AND BOUNDARY COLLISIONS SLOWING
DOWN AND ENDING LATE EVENING. LOW AND MID LEVEL DEBRIS CLOUDS
DISSIPATE AND SKIES TO BECOME PARTLY CLOUDY TO MOSTLY CLEAR LATE
NIGHT.
FRIDAY-SATURDAY...HIGHER RAIN CHANCES WILL CONTINUE INTO THE START
OF THE UPCOMING WEEKEND WITH WSW LOW LVL FLOW AND DEEP MOISTURE WITH
PRECIPITABLE WATER VALUES AROUND TWO INCHES OR GREATER INTO SATURDAY
ACROSS EAST CENTRAL FL AHEAD OF A STALLED FRONTAL BOUNDARY ACROSS S
GA AND FL PANHANDLE. MID LVL IMPULSES ARE PROGGED TO MOVE ACROSS THE
NRN FLORIDA PENINSULA FRIDAY INTO SATURDAY WHICH WILL PROVIDE
ADDITIONAL ORGANIZATION FOR STORM DEVELOPMENT BY LATE MORNING INTO
THE AFTERNOON EACH DAY. SHOULD SEE A LATE AFTERNOON SEA BREEZE NEAR
THE COAST EACH AFTERNOON BUT IT IS NOT EXPECTED TO PUSH VERY FAR
INLAND. SHOWER AND THUNDERSTORM CHANCES WILL BE AROUND 50 PCT WITH
HIGH TEMPERATURES AROUND 90/LWR 90S NEAR THE COAST TO LWR-MID 90S
OVER THE INTERIOR. LOWS WILL BE IN THE 70S.
SUNDAY...THE LOW LVL RIDGE AXIS WILL BEGIN TO LIFT NORTHWARD TWD
LAKE OKEECHOBEE WITH LIGHTER LOW LVL WINDS ACROSS SRN SECTIONS AND
LIGHT SW FLOW ACROSS THE NORTH. OVERALL MOISTURE LEVELS WILL BE ON
THE DECREASE WITH THE MID LVL RIDGE STARTING TO BUILD OVER SRN
SECTIONS. THIS SHOULD LOWER RAINFALL CHANCES INTO THE LOWER CHANCE
CATEGORY FROM 30-40 PCT WITH THE HIGHER CHANCES ACROSS INTERIOR
SECTIONS IN THE AFTERNOON. ANOTHER HOT AFTERNOON WITH HIGHS IN THE
LOWER 90S COAST TO MID 90S INTERIOR.
MON-WED...THE GFS HAS BACKED OFF ON DEEPER MOISTURE MAKING IT TO THE
AREA WITH PRONOUNCED DRYING PROGGED NEAR THE LOW-MID LYR RIDGE AXIS
WHICH WILL BE LIFTING TWD E CENTRAL FL EARLY NEXT WEEK. THE 00Z
ECMWF IS ALSO SHOWING THE DRYING TREND WITH DECREASING MOISTURE IN
THE H8-H5 LAYER BY MON-TUE. HAVE LOWERED RAIN CHANCES TO THE 20-30
PCT RANGE MON-WED OF NEXT WEEK WITH HIGHER CHANCES ACROSS INTERIOR
SECTIONS LATE IN THE DAY WITH SEA BREEZE INTERACTIONS. IT WILL
CONTINUE HOT WITH HIGHS IN THE LOWER 90S ALONG THE COAST AND MID 90S
OVER THE INTERIOR. LOWS WILL BE IN THE 70S.
&&
.AVIATION...
VFR WITH FEW-SCT025 BY 15Z. VCTS SCT-BKN040CB BY 18Z. TEMPO 3-5SM
TSRA SCT-BKN035-045CB 20Z-24Z.
PREVIOUS AVIATION DISCUSSION
PREVAILING VFR THROUGH 15Z. ISOLD TSRA DEVELOPING ACROSS REGION
AFTER 16Z...WITH SCT TSRA MOVING FROM WEST TO EAST ACROSS STATE WITH
WEST COAST SEA BREEZE THROUGH AFTERNOON. EAST COAST SEA BREEZE
DEVELOPING AFTER 17Z...REACHING KFPR/KSUA/KCOF...BUT LIKELY
REMAINING JUST EAST OF KVRB/KMLB/KTIX. BEST COVERAGE OF TSRA ALONG
COAST...WITH A FEW PRODUCING G35KTS ESPECIALLY WHERE THEY COLLIDE
WITH EAST COAST SEA BREEZE FROM KXMR SOUTHWARDS ALONG IMMEDIATE
COAST.
&&
.MARINE...
CURRENT-THIS AFTERNOON...BUOYS RECORDING SOUTHWEST WINDS AROUND 10
KNOTS AND 1 TO 2 FOOT SEAS OUT TO 20NM AND TO 3 FEET OUT 120NM.
SHORT PERIOD SEAS WILL MAKE FOR A BUMPY RIDE. BOATERS BEST TO KEEP
AN EYE TO THE WEST AFTER NOON TIME FOR SHOWERS AND LIGHTNING STORMS
APPROACHING FROM THE WEST AND SOUTHWEST. GUSTS TO 30 KNOTS POSSIBLE
WITH THE STRONGER STORMS AND FREQUENT LIGHTNING POSSIBLE
INTRACOASTAL AND NEARSHORE WATERS CAPE CANAVERAL SOUTH AS THE
PREVAILING SOUTHWEST TO WEST FLOW INTERACTS WITH THE EAST COAST SEA
BREEZE AND STORMS COMING OFF THE MAINLAND.
PREVIOUS MARINE DISCUSSION
TODAY-TONIGHT...PREVAILING SOUTHWEST FLOW CONTINUES THROUGH THE
PERIOD AS RIDGE AXIS REMAINS WELL TO THE SOUTH ACROSS THE FLORIDA
STRAITS. 10-15KTS THROUGH MID MORNING BECOMING SOUTH-SOUTHWEST
5-10KTS INTO THE AFTERNOON. LIGHTER FLOW SHOULD ALLOW MORE OF AN
EAST COAST SEA BREEZE WITH WINDS NEARSHORE SOUTH OF THE CAPE
BECOMING SOUTH-SOUTHEAST DURING THE AFTERNOON. SEAS 1-2FT WITH UP TO
3 FT WELL OFFSHORE. DOMINANT PERIODS STILL A SOMEWHAT CHOPPY
3-5SEC...MIXED WITH 8-10SEC.
BOATERS ON THE INTRACOASTAL AND NEARSHORE WATERS SHOULD KEEP AN EYE
TO THE WEST FOR APPROACHING STORMS AND SEEK SAFE HARBOR TO RIDE OUT
THE STORMS.
SW-S WINDS TO 10 TO 15 KNOTS FRI-SAT WITH OFFSHORE MOVING SHOWERS
AND LIGHTNING STORMS. THE SFC RIDGE WILL BUILD NWD TWD THE SRN
WATERS EARLY NEXT WEEK WITH S WINDS ACROSS THE SRN WATERS AND SW
WINDS NORTH OF THE CAPE. SEAS 1-2 FT NEAR SHORE TO 2-3 FT OFFSHORE.
SHOULD SEE A LOWER COVERAGE OF SHOWER/STORMS AFFECTING THE ATLC
SUNDAY INTO EARLY NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 92 76 90 76 / 50 30 50 30
MCO 95 76 92 75 / 50 30 50 30
MLB 92 75 90 76 / 50 30 50 30
VRB 92 75 91 75 / 50 30 50 30
LEE 94 77 93 77 / 50 30 50 20
SFB 95 77 93 77 / 50 30 50 30
ORL 94 77 94 78 / 50 30 50 30
FPR 91 74 91 75 / 50 30 50 30
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
FORECASTS...WIMMER
IMPACT WX...CRISTALDI
PUBLIC SVC..GLITTO
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
327 AM EDT THU AUG 14 2014
.DISCUSSION...
TODAY-TONIGHT...AS IT HAS BEEN FOR AROUND THE PAST WEEK...THERE
REMAINS VERY LITTLE CHANGE IN THE LARGER SYNOPTIC PATTERN IN PLACE
ACROSS THE STATE. DEEP TROUGH ACROSS THE NORTHEASTERN US KEEPS THE
ATLANTIC RIDGE AXIS SUPPRESSED TO OUR SOUTH...TODAY REMAINING SOUTH
OF THE STATE ACROSS THE FLORIDA STRAITS.
OVERALL GRADIENT LOOKS WEAKER TODAY LEADING TO LIGHTER
WEST-SOUTHWEST FLOW. THIS SHOULD ALLOW FOR SLIGHTLY FASTER...AND
MORE EXPANSIVE...DEVELOPMENT OF THE EAST COAST SEA BREEZE AND THIS
IS REFLECTED IN THE LOCAL HRRR AND WRF. EVEN THE GFS AND ECMWF HINT
AT A SEA BREEZE ALONG THE TREASURE COAST. HOWEVER STILL DON`T EXPECT
MUCH INLAND PENETRATION MUCH PAST THE IMMEDIATE COAST OR WEST SIDE
OF THE INDIAN RIVER LAGOON.
CENTRAL FLORIDA WILL BE MORE SOLIDLY UNDER THE INFLUENCE OF THE
LOW-MID LEVEL MOISTURE LEFT BEHIND BY THE SURFACE FRONT THAT DIED
OUT TO OUR NORTH EARLIER THIS WEEK. WHILE THIS SHOULD LEAD TO A
LITTLE BETTER COVERAGE...OVERALL CONVECTIVE EVOLUTION REMAINS
SIMILAR WITH STORMS ALONG THE WEST COAST SEA BREEZE PUSHING EAST
THROUGH THE AFTERNOON. ISOLATED SHOWERS AND STORMS WILL ALSO BE
POSSIBLE ALONG THE EAST COAST SEA BREEZE WHERE IT DOES DEVELOP
BEFORE THE EASTWARD MOVING CONVECTION REACHES IT. COVERAGE WILL
INCREASE THROUGH THE AFTERNOON DUE TO VARIOUS BOUNDARY COLLISIONS.
AS IN PREVIOUS LATE AFTERNOONS AND EVENINGS STORMS TO END AROUND
SUNSET...LOSS OF DAYTIME HEATING AND BOUNDARY COLLISIONS SLOWING
DOWN AND ENDING LATE EVENING. LOW AND MID LEVEL DEBRIS CLOUDS
DISSIPATE AND SKIES TO BECOME PARTLY CLOUDY TO MOSTLY CLEAR LATE
NIGHT.
FRIDAY-SATURDAY...HIGHER RAIN CHANCES WILL CONTINUE INTO THE START
OF THE UPCOMING WEEKEND WITH WSW LOW LVL FLOW AND DEEP MOISTURE WITH
PRECIPITABLE WATER VALUES AROUND TWO INCHES OR GREATER INTO SATURDAY
ACROSS EAST CENTRAL FL AHEAD OF A STALLED FRONTAL BOUNDARY ACROSS S
GA AND FL PANHANDLE. MID LVL IMPULSES ARE PROGGED TO MOVE ACROSS THE
NRN FLORIDA PENINSULA FRIDAY INTO SATURDAY WHICH WILL PROVIDE
ADDITIONAL ORGANIZATION FOR STORM DEVELOPMENT BY LATE MORNING INTO
THE AFTERNOON EACH DAY. SHOULD SEE A LATE AFTERNOON SEA BREEZE NEAR
THE COAST EACH AFTERNOON BUT IT IS NOT EXPECTED TO PUSH VERY FAR
INLAND. SHOWER AND THUNDERSTORM CHANCES WILL BE AROUND 50 PCT WITH
HIGH TEMPERATURES AROUND 90/LWR 90S NEAR THE COAST TO LWR-MID 90S
OVER THE INTERIOR. LOWS WILL BE IN THE 70S.
SUNDAY...THE LOW LVL RIDGE AXIS WILL BEGIN TO LIFT NORTHWARD TWD
LAKE OKEECHOBEE WITH LIGHTER LOW LVL WINDS ACROSS SRN SECTIONS AND
LIGHT SW FLOW ACROSS THE NORTH. OVERALL MOISTURE LEVELS WILL BE ON
THE DECREASE WITH THE MID LVL RIDGE STARTING TO BUILD OVER SRN
SECTIONS. THIS SHOULD LOWER RAINFALL CHANCES INTO THE LOWER CHANCE
CATEGORY FROM 30-40 PCT WITH THE HIGHER CHANCES ACROSS INTERIOR
SECTIONS IN THE AFTERNOON. ANOTHER HOT AFTERNOON WITH HIGHS IN THE
LOWER 90S COAST TO MID 90S INTERIOR.
MON-WED...THE GFS HAS BACKED OFF ON DEEPER MOISTURE MAKING IT TO THE
AREA WITH PRONOUNCED DRYING PROGGED NEAR THE LOW-MID LYR RIDGE AXIS
WHICH WILL BE LIFTING TWD E CENTRAL FL EARLY NEXT WEEK. THE 00Z
ECMWF IS ALSO SHOWING THE DRYING TREND WITH DECREASING MOISTURE IN
THE H8-H5 LAYER BY MON-TUE. HAVE LOWERED RAIN CHANCES TO THE 20-30
PCT RANGE MON-WED OF NEXT WEEK WITH HIGHER CHANCES ACROSS INTERIOR
SECTIONS LATE IN THE DAY WITH SEA BREEZE INTERACTIONS. IT WILL
CONTINUE HOT WITH HIGHS IN THE LOWER 90S ALONG THE COAST AND MID 90S
OVER THE INTERIOR. LOWS WILL BE IN THE 70S.
&&
.AVIATION...
PREVAILING VFR THROUGH 15Z. ISOLD TSRA DEVELOPING ACROSS REGION
AFTER 16Z...WITH SCT TSRA MOVING FROM WEST TO EAST ACROSS STATE WITH
WEST COAST SEA BREEZE THROUGH AFTERNOON. EAST COAST SEA BREEZE
DEVELOPING AFTER 17Z...REACHING KFPR/KSUA/KCOF...BUT LIKELY
REMAINING JUST EAST OF KVRB/KMLB/KTIX. BEST COVERAGE OF TSRA ALONG
COAST...WITH A FEW PRODUCING G35KTS ESPECIALLY WHERE THEY COLLIDE
WITH EAST COAST SEA BREEZE FROM KXMR SOUTHWARDS ALONG IMMEDIATE
COAST.
&&
.MARINE...
TODAY-TONIGHT...PREVAILING SOUTHWEST FLOW CONTINUES THROUGH THE
PERIOD AS RIDGE AXIS REMAINS WELL TO THE SOUTH ACROSS THE FLORIDA
STRAITS. 10-15KTS THROUGH MID MORNING BECOMING SOUTH-SOUTHWEST
5-10KTS INTO THE AFTERNOON. LIGHTER FLOW SHOULD ALLOW MORE OF AN
EAST COAST SEA BREEZE WITH WINDS NEARSHORE SOUTH OF THE CAPE
BECOMING SOUTH-SOUTHEAST DURING THE AFTERNOON. SEAS 1-2FT WITH UP TO
3 FT WELL OFFSHORE. DOMINANT PERIODS STILL A SOMEWHAT CHOPPY
3-5SEC...MIXED WITH 8-10SEC.
BOATERS ON THE INTRACOASTAL AND NEARSHORE WATERS SHOULD KEEP AN EYE
TO THE WEST FOR APPROACHING STORMS AND SEEK SAFE HARBOR TO RIDE OUT
THE STORMS.
SW-S WINDS TO 10 TO 15 KNOTS FRI-SAT WITH OFFSHORE MOVING SHOWERS
AND LIGHTNING STORMS. THE SFC RIDGE WILL BUILD NWD TWD THE SRN
WATERS EARLY NEXT WEEK WITH S WINDS ACROSS THE SRN WATERS AND SW
WINDS NORTH OF THE CAPE. SEAS 1-2 FT NEAR SHORE TO 2-3 FT OFFSHORE.
SHOULD SEE A LOWER COVERAGE OF SHOWER/STORMS AFFECTING THE ATLC
SUNDAY INTO EARLY NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 92 76 90 76 / 50 30 50 30
MCO 95 76 92 75 / 50 30 50 30
MLB 92 75 90 76 / 50 30 50 30
VRB 92 75 91 75 / 50 30 50 30
LEE 94 77 93 77 / 50 30 50 20
SFB 95 77 93 77 / 50 30 50 30
ORL 94 77 94 78 / 50 30 50 30
FPR 91 74 91 75 / 50 30 50 30
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM/AVIATION...MOSES
LONG TERM....VOLKMER
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
320 AM EDT THU AUG 14 2014
.DISCUSSION...
TODAY-TONIGHT...AS IT HAS BEEN FOR AROUND THE PAST WEEK...THERE
REMAINS VERY LITTLE CHANGE IN THE LARGER SYNOPTIC PATTERN IN PLACE
ACROSS THE STATE. DEEP TROUGH ACROSS THE NORTHEASTERN US KEEPS THE
ATLANTIC RIDGE AXIS SUPPRESSED TO OUR SOUTH...TODAY REMAINING SOUTH
OF THE STATE ACROSS THE FLORIDA STRAITS.
OVERALL GRADIENT LOOKS WEAKER TODAY LEADING TO LIGHTER
WEST-SOUTHWEST FLOW. THIS SHOULD ALLOW FOR SLIGHTLY FASTER...AND
MORE EXPANSIVE...DEVELOPMENT OF THE EAST COAST SEA BREEZE AND THIS
IS REFLECTED IN THE LOCAL HRRR AND WRF. EVEN THE GFS AND ECMWF HINT
AT A SEA BREEZE ALONG THE TREASURE COAST. HOWEVER STILL DON`T EXPECT
MUCH INLAND PENETRATION MUCH PAST THE IMMEDIATE COAST OR WEST SIDE
OF THE INDIAN RIVER LAGOON.
CENTRAL FLORIDA WILL BE MORE SOLIDLY UNDER THE INFLUENCE OF THE
LOW-MID LEVEL MOISTURE LEFT BEHIND BY THE SURFACE FRONT THAT DIED
OUT TO OUR NORTH EARLIER THIS WEEK. WHILE THIS SHOULD LEAD TO A
LITTLE BETTER COVERAGE...OVERALL CONVECTIVE EVOLUTION REMAINS
SIMILAR WITH STORMS ALONG THE WEST COAST SEA BREEZE PUSHING EAST
THROUGH THE AFTERNOON. ISOLATED SHOWERS AND STORMS WILL ALSO BE
POSSIBLE ALONG THE EAST COAST SEA BREEZE WHERE IT DOES DEVELOP
BEFORE THE EASTWARD MOVING CONVECTION REACHES IT. COVERAGE WILL
INCREASE THROUGH THE AFTERNOON DUE TO VARIOUS BOUNDARY COLLISIONS.
AS IN PREVIOUS LATE AFTERNOONS AND EVENINGS STORMS TO END AROUND
SUNSET...LOSS OF DAYTIME HEATING AND BOUNDARY COLLISIONS SLOWING
DOWN AND ENDING LATE EVENING. LOW AND MID LEVEL DEBRIS CLOUDS
DISSIPATE AND SKIES TO BECOME PARTLY CLOUDY TO MOSTLY CLEAR LATE
NIGHT.
FRIDAY-SATURDAY...HIGHER RAIN CHANCES WILL CONTINUE INTO THE START
OF THE UPCOMING WEEKEND WITH WSW LOW LVL FLOW AND DEEP MOISTURE WITH
PRECIPITABLE WATER VALUES AROUND TWO INCHES OR GREATER INTO SATURDAY
ACROSS EAST CENTRAL FL AHEAD OF A STALLED FRONTAL BOUNDARY ACROSS S
GA AND FL PANHANDLE. MID LVL IMPULSES ARE PROGGED TO MOVE ACROSS THE
NRN FLORIDA PENINSULA FRIDAY INTO SATURDAY WHICH WILL PROVIDE
ADDITIONAL ORGANIZATION FOR STORM DEVELOPMENT BY LATE MORNING INTO
THE AFTERNOON EACH DAY. SHOULD SEE A LATE AFTERNOON SEA BREEZE NEAR
THE COAST EACH AFTERNOON BUT IT IS NOT EXPECTED TO PUSH VERY FAR
INLAND. SHOWER AND THUNDERSTORM CHANCES WILL BE AROUND 50 PCT WITH
HIGH TEMPERATURES AROUND 90/LWR 90S NEAR THE COAST TO LWR-MID 90S
OVER THE INTERIOR. LOWS WILL BE IN THE 70S.
SUNDAY...THE LOW LVL RIDGE AXIS WILL BEGIN TO LIFT NORTHWARD TWD
LAKE OKEECHOBEE WITH LIGHTER LOW LVL WINDS ACROSS SRN SECTIONS AND
LIGHT SW FLOW ACROSS THE NORTH. OVERALL MOISTURE LEVELS WILL BE ON
THE DECREASE WITH THE MID LVL RIDGE STARTING TO BUILD OVER SRN
SECTIONS. THIS SHOULD LOWER RAINFALL CHANCES INTO THE LOWER CHANCE
CATEGORY FROM 30-40 PCT WITH THE HIGHER CHANCES ACROSS INTERIOR
SECTIONS IN THE AFTERNOON. ANOTHER HOT AFTERNOON WITH HIGHS IN THE
LOWER 90S COAST TO MID 90S INTERIOR.
MON-WED...THE GFS HAS BACKED OFF ON DEEPER MOISTURE MAKING IT TO THE
AREA WITH PRONOUNCED DRYING PROGGED NEAR THE LOW-MID LYR RIDGE AXIS
WHICH WILL BE LIFTING TWD E CENTRAL FL EARLY NEXT WEEK. THE 00Z
ECMWF IS ALSO SHOWING THE DRYING TREND WITH DECREASING MOISTURE IN
THE H8-H5 LAYER BY MON-TUE. HAVE LOWERED RAIN CHANCES TO THE 20-30
PCT RANGE MON-WED OF NEXT WEEK WITH HIGHER CHANCES ACROSS INTERIOR
SECTIONS LATE IN THE DAY WITH SEA BREEZE INTERACTIONS. IT WILL
CONTINUE HOT WITH HIGHS IN THE LOWER 90S ALONG THE COAST AND MID 90S
OVER THE INTERIOR. LOWS WILL BE IN THE 70S.
&&
.AVIATION...
PREVAILING VFR THROUGH 15Z. ISOLD TSRA DEVELOPING ACROSS REGION
AFTER 16Z...WITH SCT TSRA MOVING FROM WEST TO EAST ACROSS STATE WITH
WEST COAST SEA BREEZE THROUGH AFTERNOON. EAST COAST SEA BREEZE
DEVELOPING AFTER 17Z...REACHING KFPR/KSUA/KCOF...BUT LIKELY
REMAINING JUST EAST OF KVRB/KMLB/KTIX. BEST COVERAGE OF TSRA ALONG
COAST...WITH A FEW PRODUCING G35KTS ESPECIALLY WHERE THEY COLLIDE
WITH EAST COAST SEA BREEZE FROM KXMR SOUTHWARDS ALONG IMMEDIATE
COAST.
&&
.MARINE...
TODAY-TONIGHT...HIGH PRESSURE REMAINS TO THE SOUTH THEREFORE
MODERATE SOUTHWEST TO WEST WILL CONTINUE OVERNIGHT. BOATERS ON THE
INTRACOASTAL AND NEARSHORE WATERS SHOULD KEEP AN EYE TO THE WEST FOR
APPROACHING STORMS AND SEEK SAFE HARBOR TO RIDE OUT THE STORMS.
SW-S WINDS TO 10 TO 15 KNOTS FRI-SAT WITH OFFSHORE MOVING SHOWERS
AND LIGHTNING STORMS. THE SFC RIDGE WILL BUILD NWD TWD THE SRN
WATERS EARLY NEXT WEEK WITH S WINDS ACROSS THE SRN WATERS AND SW
WINDS NORTH OF THE CAPE. SEAS 1-2 FT NEAR SHORE TO 2-3 FT OFFSHORE.
SHOULD SEE A LOWER COVERAGE OF SHOWER/STORMS AFFECTING THE ATLC
SUNDAY INTO EARLY NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 92 76 90 76 / 50 30 50 30
MCO 95 76 92 75 / 50 30 50 30
MLB 92 75 90 76 / 50 30 50 30
VRB 92 75 91 75 / 50 30 50 30
LEE 94 77 93 77 / 50 30 50 20
SFB 95 77 93 77 / 50 30 50 30
ORL 94 77 94 78 / 50 30 50 30
FPR 91 74 91 75 / 50 30 50 30
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM/AVIATION...MOSES
LONG TERM....VOLKMER
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1206 AM EDT SAT AUG 16 2014
.SYNOPSIS...
HIGH PRESSURE EXTENDING FROM THE ATLANTIC WESTWARD ALONG THE GULF
COAST WILL DOMINATE DURING THE WEEKEND. THIS FEATURE WILL KEEP THE
FORECAST AREA MAINLY DRY WITH SEASONABLE TEMPERATURES.
&&
.NEAR TERM /OVERNIGHT/...
A WEAK PRESSURE TROUGH WILL CONTINUE IN THE FORECAST AREA. CURRENT
RADAR INDICATING ISOLATED SHOWERS CLOSER TO THE COAST...WITH ALL
OF THE CWA CURRENTLY DRY. THERE WILL BE A MID-LEVEL SHORTWAVE
TROUGH APPROACHING IN THE NORTHWEST FLOW. LOW-LEVEL MOISTURE
BENEATH THE NOCTURNAL INVERSION SHOULD HELP SUPPORT AREAS OF
STRATUS AND FOG TOWARD MORNING. USED THE GUIDANCE CONSENSUS FOR
THE TEMPERATURE FORECAST.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
THE NAM AND GFS DISPLAY HIGH PRESSURE RIDGING FROM THE ATLANTIC
WESTWARD ALONG THE GULF COAST THROUGH SUNDAY. THE MODELS KEEP
DEEPER MOISTURE ASSOCIATED WITH THE REMNANTS OF A FRONT SOUTH OF
THE FORECAST AREA. MUCH OF THE MOISTURE ASSOCIATED WITH ANOTHER
FRONT SHOULD REMAIN NORTHWEST OF THE AREA THROUGH SUNDAY. THE
MODELS INDICATE LEE-SIDE TROUGHING. CONVERGENCE INTO THIS FEATURE
PLUS STRONG HEATING COULD SUPPORT THUNDERSTORMS BUT THE CHANCE IS
LOW BECAUSE OF JUST SHALLOW MOISTURE AND POSSIBLY MID-LEVEL
CAPPING ASSOCIATED WITH SHORTWAVE RIDGING. ALL OF THE NAM AND GFS
MOS POPS ARE LESS THAN 20 PERCENT. USED THE GUIDANCE CONSENSUS FOR
THE TEMPERATURE FORECAST.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
THE GFS AND ECMWF DISPLAY RIDGING EXTENDING FROM THE ATLANTIC
WESTWARD NEAR THE GULF COAST THROUGH THE MEDIUM-RANGE PERIOD.
FARTHER NORTH THE MODELS SHOW LEE-SIDE TROUGHING IN THE FORECAST AREA
DURING MUCH OF THE PERIOD. A FRONT DROPPING SOUTHWARD MAY EXTEND
THROUGH THE FORECAST AREA DURING PART OF THE PERIOD. THE RIDGE TO
THE SOUTH SHOULD LIMIT MOISTURE. THE MODELS SHOW STRONGER
CONVERGENCE AND DEEPER MOISTURE NORTH OF THE FORECAST AREA. THE
GFS...ECMWF...AND EKD MOS HAVE POPS 20 TO 30 PERCENT. EXPECT HIGH
TEMPERATURES ABOVE NORMAL WITH THE RIDGE TO THE SOUTH DIRECTING A
WESTERLY FLOW INTO THE FORECAST AREA. THE GUIDANCE HAS HIGHS MAINLY
IN THE MIDDLE 90S THROUGH THE PERIOD.
&&
.AVIATION /04Z SATURDAY THROUGH WEDNESDAY/...
VFR CONDITIONS THROUGH THE PERIOD...WITH MVFR POSSIBLE LATE
TONIGHT/EARLY SATURDAY MORNING IN FOG.
CLEAR SKIES AND LIGHT AND VARIABLE WINDS THROUGH THE OVERNIGHT
PERIOD WILL PROMOTE FOG DEVELOPMENT MAINLY AFTER 07Z. HRRR MODEL
SHOWS A MORE AGGRESSIVE FOG SCENARIO THAN SOME OF THE OTHER
MODELS. HAVE INCLUDED MVFR/IFR GROUP AT FOG PRONE AGS/OGB WHERE
FOG ALSO DEVELOPED LAST NIGHT. CONFIDENCE REMAINS TOO LOW AT THE
MOMENT TO INCLUDE FOG AT CAE/DNL/CUB. FOG SHOULD DISSIPATE BY
13Z AND WINDS WILL PICK UP OUT OF THE SOUTHWEST AT 5 TO 7 KNOTS
OR LESS.
EXTENDED AVIATION OUTLOOK...MVFR CONDITIONS POSSIBLE IN LATE
NIGHT/EARLY MORNING FOG EACH NIGHT. SCATTERED AFTERNOON/EVENING
SHOWERS AND THUNDERSTORMS POSSIBLE MONDAY AND TUESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
756 PM EDT FRI AUG 15 2014
.SYNOPSIS...
HIGH PRESSURE EXTENDING FROM THE ATLANTIC WESTWARD ALONG THE GULF
COAST WILL DOMINATE DURING THE WEEKEND. THIS FEATURE WILL KEEP THE
FORECAST AREA MAINLY DRY WITH SEASONABLE TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
A WEAK PRESSURE TROUGH WILL CONTINUE IN THE FORECAST AREA. CURRENT
RADAR INDICATING ISOLATED SHOWERS IN THE EAST-CENTRAL MIDLANDS.
THERE WILL ALSO BE A MID-LEVEL SHORTWAVE TROUGH APPROACHING IN THE
NORTHWEST FLOW. DESPITE THIS SUPPORT BELIEVE ISOLATED THUNDERSTORMS
WILL DISSIPATE EARLY BECAUSE OF THE LOSS OF HEATING AND CONTINUED
SHALLOW MOISTURE. LOW-LEVEL MOISTURE BENEATH THE NOCTURNAL
INVERSION SHOULD HELP SUPPORT AREAS OF STRATUS AND FOG TOWARD
MORNING. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY/...
THE NAM AND GFS DISPLAY HIGH PRESSURE RIDGING FROM THE ATLANTIC
WESTWARD ALONG THE GULF COAST THROUGH SUNDAY. THE MODELS KEEP DEEPER
MOISTURE ASSOCIATED WITH THE REMNANTS OF A FRONT SOUTH OF THE
FORECAST AREA. MUCH OF THE MOISTURE ASSOCIATED WITH ANOTHER FRONT
SHOULD REMAIN NORTHWEST OF THE AREA THROUGH SUNDAY. THE MODELS
INDICATE LEE-SIDE TROUGHING. CONVERGENCE INTO THIS FEATURE PLUS
STRONG HEATING COULD SUPPORT THUNDERSTORMS BUT THE CHANCE IS LOW
BECAUSE OF JUST SHALLOW MOISTURE AND POSSIBLY MID-LEVEL CAPPING
ASSOCIATED WITH SHORTWAVE RIDGING. ALL OF THE NAM AND GFS MOS POPS
ARE LESS THAN 20 PERCENT. USED THE GUIDANCE CONSENSUS FOR THE
TEMPERATURE FORECAST.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
THE GFS AND ECMWF DISPLAY RIDGING EXTENDING FROM THE ATLANTIC
WESTWARD NEAR THE GULF COAST THROUGH THE MEDIUM-RANGE PERIOD.
FARTHER NORTH THE MODELS SHOW LEE-SIDE TROUGHING IN THE FORECAST AREA
DURING MUCH OF THE PERIOD. A FRONT DROPPING SOUTHWARD MAY EXTEND
THROUGH THE FORECAST AREA DURING PART OF THE PERIOD. THE RIDGE TO
THE SOUTH SHOULD LIMIT MOISTURE. THE MODELS SHOW STRONGER
CONVERGENCE AND DEEPER MOISTURE NORTH OF THE FORECAST AREA. THE
GFS...ECMWF...AND EKD MOS HAVE POPS 20 TO 30 PERCENT. EXPECT HIGH
TEMPERATURES ABOVE NORMAL WITH THE RIDGE TO THE SOUTH DIRECTING A
WESTERLY FLOW INTO THE FORECAST AREA. THE GUIDANCE HAS HIGHS MAINLY
IN THE MIDDLE 90S THROUGH THE PERIOD.
&&
.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
VFR CONDITIONS THROUGH THE PERIOD...WITH MVFR POSSIBLE LATE
TONIGHT/EARLY SATURDAY MORNING IN FOG.
ISOLATED SHOWER ACTIVITY AND CUMULUS WILL CONTINUE TO DISSIPATE WITH
SUNSET THIS EVENING. CLEAR SKIES AND LIGHT AND VARIABLE WINDS
THROUGH THE OVERNIGHT PERIOD WILL PROMOTE FOG DEVELOPMENT MAINLY
AFTER 16/07Z. HRRR MODEL SHOWS A MORE AGGRESSIVE FOG SCENARIO THAN
SOME OF THE OTHER MODELS. HAVE INCLUDED MVFR/IFR GROUP AT FOG
PRONE AGS/OGB WHERE FOG ALSO DEVELOPED LAST NIGHT. CONFIDENCE
REMAINS TOO LOW AT THE MOMENT TO INCLUDE FOG AT CAE/DNL/CUB. FOG
SHOULD DISSIPATE BY 16/13Z AND WINDS WILL PICK UP OUT OF THE
SOUTHWEST AT 5 TO 7 KNOTS OR LESS.
EXTENDED AVIATION OUTLOOK...MVFR CONDITIONS POSSIBLE IN LATE
NIGHT/EARLY MORNING FOG EACH NIGHT. SCATTERED AFTERNOON/EVENING
SHOWERS AND THUNDERSTORMS POSSIBLE MONDAY AND TUESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1005 PM CDT FRI AUG 15 2014
.DISCUSSION...
254 PM CDT
THE MAIN FORECAST CONCERNS WILL CONTINUE TO FOCUS ON THE CHANCES OF
THUNDERSTORMS AND THE POSSIBILITY OF HEAVY RAIN ACROSS PORTIONS OF MY
AREA THROUGH THE WEEKEND.
COOL SURFACE HIGH PRESSURE CONTINUES TO SHIFT EAST-SOUTHEASTWARD
OVER THE OHIO VALLEY EARLY THIS AFTERNOON. THIS IS PRODUCING ANOTHER
FABULOUS WEATHER DAY ACROSS THE REGION THIS AFTERNOON WITH
TEMPERATURES PRIMARILY IN THE MID TO UPPER 70S. HOWEVER...ATTENTION
IS BEGINNING TO FOCUS ON THE SYSTEM TO OUR WEST...WHICH IS ALREADY
PUSHING SOME HIGHER LEVEL CLOUDINESS INTO MY SOUTHWESTERN AREAS.
WATER VAPOR IMAGERY EARLY THIS AFTERNOON INDICATES THE PRESENCE OF A
COUPLE OF MID/UPPER LEVEL DISTURBANCES ACROSS THE PLAINS. THE FIRST
IS LOCATED OVER THE WESTERN DAKOTAS...WITH THE SECOND OVER THE
NEBRASKA-KANSAS BOARDER. HOWEVER...IT IS THE SOUTHERNMOST
DISTURBANCE THAT IS THE MAIN FOCUS FOR THE WEATHER EXPECTED MUCH OF
THIS WEEKEND ACROSS NORTHERN ILLINOIS/NORTHWESTERN INDIANA. MODEL
GUIDANCE IS IN GOOD AGREEMENT WITH TRACKING THIS DISTURBANCE SLOWLY
EASTWARD ACROSS SOUTHERN IOWA TONIGHT...THEN EAST-SOUTHEASTWARD
ACROSS CENTRAL ILLINOIS BY SUNDAY MORNING. THE GFS AND ECMWF ARE
FAVORED WITH THE HANDLING OF THE SYSTEM THROUGH THE WEEKEND.
CONVECTIVE ACTIVITY WILL LIKELY FIRE UP DOWNSTREAM OF THE SOUTHERN
NEBRASKA DISTURBANCE TONIGHT...NAMELY ACROSS PORTIONS OF SOUTHERN
IOWA...MISSOURI AND PERHAPS ACROSS FAR WESTERN ILLINOIS ALONG THE
NOSE OF A DEVELOPING SOUTH-SOUTHWESTERLY LOW LEVEL JET. THE REMNANTS
OF SOME OF THIS ACTIVITY WILL TRY TO MOVE EASTWARD ACROSS THE AREA
SATURDAY MORNING. HOWEVER...IT APPEARS THIS ACTIVITY WILL LIKELY
WEAKEN CONSIDERABLY WITH EASTWARD EXTENT DURING THE MORNING AS IT
MOVES AWAY FROM THE BETTER FORCING AND INSTABILITY. AS SUCH...IT
APPEARS THE THREAT FOR THUNDERSTORMS WILL BE LOW ACROSS MUCH OF
NORTHEASTERN ILLINOIS AND INTO INDIANA...WITH POSSIBLY ONLY SOME
SHOWERS VOID OF THUNDER POSSIBLE.
ADDITIONAL SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE SATURDAY
AFTERNOON AND NIGHT AS THE MAIN UPPER SYSTEM MOVES FROM SOUTHEASTERN
IOWA OVER CENTRAL ILLINOIS. HOWEVER...AGAIN IT APPEARS THE MAIN
THREAT OF THUNDER WILL REMAIN ALONG AND SOUTH OF INTERSTATE 80 TO
THE EAST OF THE TRACK OF THE MID LEVEL WAVE. THERE IS A THREAT FOR
SOME VERY HEAVY RAINFALL WITH THESE STORMS ON SATURDAY/SATURDAY
NIGHT ACROSS CENTRAL ILLINOIS GIVEN PWATS COULD BE IN EXCESS OF 2
INCHES AND WARM CLOUD DEPTHS IN EXCESS OF 13,000 FEET. THIS THREAT
WILL NEED TO BE WATCHED...BUT AT THIS TIME IT APPEARS THE PRIMARILY
THREAT FOR THIS HEAVY RAINFALL COULD REMAIN JUST OUTSIDE MY AREA.
A COLD FRONT IS ALSO EXPECTED TO DROP DOWN LAKE MICHIGAN LATE
SATURDAY. THIS COLD FRONT SHOULD SHIFT SOUTHWARD ACROSS NORTHERN
ILLINOIS BY LATE SATURDAY NIGHT/EARLY SUNDAY MORNING. ONCE THIS
FRONT PUSHES THROUGH...ONSHORE FLOW WILL PREVAIL ACROSS NORTHEASTERN
ILLINOIS AND PORTIONS OF NORTHWESTERN INDIANA. THIS SHOULD KEEP MUCH
OF NORTHERN ILLINOIS DRY BUT CLOUDY ON SUNDAY. AS A RESULT...I
HAVE DROPPED POPS ACROSS MUCH OF NORTHERN ILLINOIS ON SUNDAY.
HOWEVER...THE EFFECTS OF THE MID LEVEL SYSTEM WILL STILL POSSIBLY
LEAD TO ADDITIONAL THUNDERSTORMS SUNDAY...PRIMARILY ACROSS MY EAST
CENTRAL ILLINOIS AND NORTHWESTERN INDIANA COUNTIES. HEAVY RAINFALL
WILL AGAIN BE A THREAT WITH THESE STORMS.
THINGS FINALLY QUITE DOWN AREA-WIDE FOR A SHORT PERIOD LATE MONDAY.
HOWEVER...THE WEATHER PATTERN FROM MID TO LATE THIS COMING WEEK
LOOKS TO BE A WARMER AND ACTIVE AT TIMES. THE UPPER LOW/TROUGH
CURRENT IN PLACE ACROSS THE PACIFIC NORTHWEST IS PROGGED TO SHIFT
EASTWARD ACROSS THE UPPER MIDWEST BY TUESDAY. THIS WILL BRING OUR
NEXT CHANCE OF SHOWERS AND STORMS TO AREA...ALONG WITH WARMER
TEMPERATURES. ADDITIONAL WAVES OF STORMS ARE POSSIBLE LATER IN THE
WEEK AS WELL WITH THE LIKELIHOOD OF THE MID/UPPER LEVEL PATTERN
REMAINING DISTURBED ACROSS THE NORTHERN HALF OF THE COUNTRY.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* SOUTHWEST WINDS AROUND 10 KT AT TIMES SATURDAY AFTERNOON.
* A CHANCE FOR SHOWERS AND A SMALLER CHANCE OF THUNDERSTORMS FROM
MID SATURDAY AFTERNOON THROUGH EARLY SATURDAY EVENING.
//DISCUSSION...UPDATED 00Z...
HIGH PRESSURE WILL CONTINUE TO DEPART TO THE EAST WITH SOUTHERLY
WINDS OVER THE TAF SITES. GRADUALLY INCREASING MOISTURE COULD
DEVELOP SOME MVFR CLOUDS OVER WESTERN/NORTHWESTERN IL LATE
TONIGHT THAT MAY CLIP RFD INTO SATURDAY MORNING. SOUTHWEST WINDS
ARE EXPECTED DURING THE DAY SATURDAY WHICH ARE EXPECTED TO PEAK
AROUND 10 KT DURING THE LATE MORNING AND AFTERNOON. SOME MODEL
GUIDANCE WOULD INDICATE THE CHANCE FOR OCCASIONAL STRONGER SPEEDS
SUCH AS 12-14 KT AT ORD AND MDW. GIVEN THE AMOUNT OF CLOUD COVER
EXPECTED...MIXING AND MAGNITUDE OF GUSTS ARE EXPECTED TO BE LESS
THAN WHAT GUIDANCE IS INDICATING.
A LOW PRESSURE SYSTEM MOVING VERY SLOWLY FROM WESTERN IA VERY LATE
TONIGHT TO NORTHEAST MO SATURDAY NIGHT WILL SPREAD SHOWERS INTO
CENTRAL IL LATE SATURDAY MORNING INTO THE AFTERNOON. THIS WILL BE
MET WITH DRY AIR TO THE NORTH AND NORTHEAST WHICH WILL CERTAINLY
KEEP INSTABILITY LESS OVER TAF SITES AND MAY PREVENT ANY SHOWERS
ALL TOGETHER. HAVE GONE WITH A VCSH FOR CHICAGOLAND SITES FOR THE
TIME BEING LATE IN THE AFTERNOON EARLY EVE.
LATE SATURDAY NIGHT A COLD FRONT WILL MOVE SOUTHWARD ACROSS THE
WESTERN GREAT LAKES. SUCH FEATURES CAN OFTEN SPEED UP DOWN LAKE
MI SO THIS COULD CONCEIVABLY REACH CHICAGOLAND SITES PRIOR TO 06Z
SUNDAY. WINDS WILL TURN NORTH-NORTHEAST WITH SPEEDS LIKELY 10 KT
OR HIGHER INTO SUNDAY MORNING. IN ADDITION...A PERIOD OF BROKEN
CIGS UNDER 2000 FT ARE PROBABLE THOUGH HOW LONG IS NOT YET
CERTAIN.
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* HIGH IN WIND DIRECTION AND MEDIUM IN WIND SPEEDS AROUND 10 KT ON
SATURDAY.
* LOW IN WHETHER ANY SHOWERS WILL DEVELOP AS FAR NORTH AS THE
CHICAGOLAND TERMINALS ON SATURDAY AFTERNOON AND EVENING.
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...NORTHEAST WINDS OVER 10 KT WITH PROBABLE MVFR CIGS IN THE
MORNING.
MONDAY...NORTHEAST WINDS.
TUESDAY-THURSDAY...CHANCE OF TSRA.
MTF
&&
.MARINE...
215 PM CDT
LARGE AREA OF HIGH PRESSURE CENTERED JUST SOUTH OF LAKE MICHIGAN
WILL SHIFT SOUTHEAST TONIGHT. A WEAK LOW PRESSURE SYSTEM IN SOUTH
CENTRAL CANADA WILL DEEPEN SOME TONIGHT AS IT PASSES JUST NORTH OF
THE UPPER GREAT LAKES REGION. THE PRESSURE GRADIENT INCREASES
OVERNIGHT INTO EARLY SATURDAY MORNING...ESPECIALLY ALONG THE
NORTHERN HALF OF THE LAKE. THIS WILL MAINTAIN SW FLOW
TONIGHT...WITH WINDS APPROACHING 25-30 KT FOR A BRIEF TIME IN THE
NORTH LATE TONIGHT. BEHIND THE LOW...HIGH PRESSURE BUILDS INTO
SOUTHERN ONTARIO AND SENDS A COLD FRONT SOUTH DOWN THE LAKE
SATURDAY AFTERNOON AND EVENING. ADDITIONALLY...AN AREA OF LOW
PRESSURE IN THE CENTRAL PLAINS WILL SLOWLY DRIFT EAST TO THE OHIO
VALLEY BY LATE SUNDAY THEN CONTINUE TO THE ATLANTIC SEABOARD
MONDAY. THIS WILL HELP MAINTAIN OR A PERIOD OF NORTH TO
NORTHEASTERLY WINDS. ADDITIONAL WEAKER LOW PRESSURE AREAS WILL
PUSH TOWARD THE GREAT LAKES NEXT WEEK...MAINTAINING A SOUTH
COMPONENT TO THE WIND WITH OCCASIONAL THUNDERSTORMS THROUGH MID
WEEK.
KMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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[top]
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
905 PM CDT Fri Aug 15 2014
.UPDATE...
ISSUED AT 904 PM CDT FRI AUG 15 2014
A few weakening disturbances are set to move through central
Illinois through Saturday. The first is largely through Illinois
already, moving rapidly off to the east, and resulted in isolated
to scattered showers from around Galesburg to Lawrenceville
earlier in the evening. The next is moving ESE through Missouri at
this time producing widespread showers and a few thunderstorms.
HRRR model progs bring this into central IL over the next few
hours, again mainly affecting Galesburg to Lawrenceville southward
while weakening as instability fades with the loss of daytime
heating. By Saturday afternoon, yet another disturbance is
expected to approach as a deeper slow moving 500 mb trough and
surface low develop over northeast Missouri. Precipitable water
values over 2 inches inches are expected to be associated with the
system, so there will be a threat for heavy rain as this moves
across southern Illinois Saturday evening. Have updated forecast
to account for temperature, humidity and precipitation trends
over the next several hours.
&&
.SHORT TERM...(This evening through Saturday)
ISSUED AT 307 PM CDT FRI AUG 15 2014
Decaying MCS moving toward the CWA early this afternoon, with some
light showers being reported near Galesburg. Most precipitation
still west of the Mississippi River, with the HRRR showing it
reaching about as far east as Springfield late this afternoon before
diminishing. Latest LAPS soundings from Springfield and Jacksonville
showing a fair amount of dry air below 700 mb, so am not expecting a
lot of accumulation out of this.
Shortwave currently moving southeast out of South Dakota/Nebraska
starting to produce additional storms in Kansas, and this area of
storms should expand as the wave moves eastward and the low level
jet increases. HRRR and NAM show this next MCS approaching far
western Illinois by late evening, but the other high-res models such
as the ARW and NMM are a bit slower with arrival across the western
CWA after about 2-3 am. All models show the MCS diminishing during
the morning, but redevelopment taking place toward late afternoon in
the west near a surface low in southeast Iowa. Extensive cloud cover
should mitigate much of the severe weather potential, but
precipitable water values increasing to over 2 inches will result in
some locally heavy rains.
&&
.LONG TERM...(Saturday night through Friday)
ISSUED AT 307 PM CDT FRI AUG 15 2014
Occluded low pressure will reach western IL around 00z/7pm Saturday,
bringing abundant moisture with the potential for some heavy rains.
The latest model runs have shown a diminishing threat for strong
storms in western IL, and SPC has reduced the 5% threat area to just
west of a line from Rushville to Springfield. The threat for thunder
in general will remain low due to limited ice formation and only
weak instability. Limited afternoon sunshine after morning rain
showers will also help to keep instability in check for Saturday
evening. Rain will be likely during the evening southwest of
Lincoln, then expand to the Indiana border after midnight Sat night.
Likely rain will continue on Sunday east of I-55 as the slow moving
low pressure system moves to near LWV by 00z/7pm Sunday. Bufkit
sounding analysis shows better instability ahead of the low in our
southeast areas Sunday afternoon, with MUCAPE up to 1500 J/kg, but
confidence is low that storms will become very strong due to limited
sunshine once again.
Precipitable water values will remain very high through Sunday with
2" to 2.3" across most of central and southeast IL. Locally heavy
rainfall from Saturday through Sunday evening could push 2 day totals
between 2" and 3".
As the low pulls east of IL on Sunday night, we expect diminishing
precip chances from west to east, with a break in the rain expected
at least on Monday. The Canadian GEM still indicated lingering
rain in most of our area, so we left some slight chance PoPs for
Monday.
The next weather system will arrive quickly late Monday night and
Tuesday, with increasing precip chances NW of the IL Monday night.
Relatively good agreement of a warm front moving east across IL on
Tuesday prompted chance PoPs across the board. The upper trough will
deepen into IL on Tuesday night and Wed, with a trailing cold front
lingering across IL through Thursday, keeping rain chances
entrenched in the forecast through Thursday night. Warm and very
muggy air will dominate the mid week period with the rain chances,
as dewpoints remain in the low 70s and highs climb into the mid to
upper 80s.
Friday should bring a break in the rain as upper level ridging
develops bringing even warmer air into central IL the following
weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
ISSUED AT 659 PM CDT FRI AUG 15 2014
A decaying area of showers affecting areas of central IL from
around KLWV-KGBG southward with isolated-scattered showers, but
ceilings/visibilities well above MVFR thresholds. No clear break
in light shower activity in this region until the next disturbance
moves in late tonight from northern MO. TAFs include -shra/vcsh
starting 07Z-12Z to account for this second disturbance. A series
of trailing disturbances will then bring periods of redevelopment
of showers through the remainder of the 24-hour TAF period, with
ceilings just above MVFR thresholds. There may be a break in
shower activity from around 16Z-22Z, but timing is too uncertain
for explicit mention of a break in showers. Time-height plots
show very little improvement in ceilings in this time period,
continuing around 4-5 kft AGL.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...ONTON
SHORT TERM...GEELHART
LONG TERM...SHIMON
AVIATION...ONTON
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1252 PM CDT THU AUG 14 2014
.DISCUSSION...
302 AM CDT
SHORT TERM (THROUGH TONIGHT)...
HIGH PRESSURE IS CENTERED THIS MORNING OVER ONTARIO WITH RIDGING
EXTENDING SOUTH ALONG THE UPPER AND MID MISSISSIPPI VALLEY. UPPER
PATTERN IS AMPLIFIED WITH A CLOSED LOW ANALYZED OVER THE EASTERN
GREAT LAKES WITH RIDGING ACROSS THE PLAINS LEAVING THE LOCAL AREA
UNDER NORTHWEST FLOW ALOFT. SOME CIRRUS STREAMING DOWN THE LEE SIDE
OF THE RIDGE WILL OCCUR THROUGH THE DAY...OTHERWISE DRIER LOW LEVELS
BEHIND A DEPARTING COLD FRONT SHOULD RESULT IN MOSTLY SUNNY SKIES.
SURFACE WINDS OFF THE LAKE THROUGH THE DAY WILL KEEP TEMPERATURES A
BIT COOLER...LIKELY STRUGGLING TO REACH 70 IMMEDIATELY NEAR THE LAKE
FRONT...BUT RISING INTO THE MID 70S FARTHER INLAND.
TONIGHT...THE HIGH WILL MOVE SOUTH ACROSS THE LOCAL AREA WITH WINDS
DROPPING OFF AND LIKELY GOING VARIABLE OR CALM FOR A PERIOD...THEN
TURN SOUTHWEST BY LATE TONIGHT AS THE HIGH HEADS TOWARDS THE UPPER
OHIO RIVER VALLEY. TEMPERATURES ARE EXPECTED TO DROP INTO THE LOW TO
MID 50S TONIGHT OUTSIDE OF THE CITY...WHICH WILL STAY AROUND 60.
DEUBELBEISS
LONG TERM (FRIDAY THROUGH WEDNESDAY)...
PRIMARY FORECAST CHALLENGE IS PRECIP CHANCES THROUGH THE WEEKEND
INTO EARLY NEXT WEEK ASSOCIATED WITH FAIRLY STRONG SHORTWAVE OVER
THE ROCKIES THAT WILL CREST THE UPPER RIDGE BEFORE DROPPING
SOUTHEAST INTO OUR NECK OF THE WOODS OVER THE WEEKEND.
FIRST...GFS HAS ABANDONED THE MORE PHASED SOLUTION OF LAST NIGHT AND
IS NOW THE OPERATIONAL RUN OF THE GFS AND ENSEMBLE MEAN ARE FAIRLY
TIGHTLY CLUSTERED WITH THE ECMWF/GEM SOLUTIONS. THE LESS PHASED
SOLUTION ADDS CONFIDENCE TO A SLOWER MOVEMENT AND LATER ONSET TO THE
START TIME OF PRECIP CHANCES THIS WEEKEND. IN ADDITION...ALL MEDIUM
RANGE MODELS HAVE TRENDED STRONGER WITH THIS SHORTWAVE AND MORE
IMPORTANTLY SIGNIFICANTLY FARTHER SOUTHWEST WITH THE TRACK. THE
LATEST MEDIUM GUIDANCE WOULD ACTUALLY OPEN THE DOOR TO THE
POSSIBILITY THAT MUCH OF THE UPCOMING WEEKEND COULD END UP
DRY...ESPECIALLY NORTHEASTERN CWA AS THE SYSTEM CUTS OFF OVER
NORTHERN MISSOURI SAT INTO EARLY SUNDAY. BY SUNDAY NIGHT INTO EARLY
NEXT WEEK GUIDANCE SUGGESTS THE WAVE WILL TAKE MORE OF A LEFT TURN
AND TRACK EASTERLY AS THE NE NOAM TROUGH DISSIPATES AND THE FLOW
FLATTENS OUT AND NEXT UPSTREAM WAVE ACTS AS A KICKER GIVING THIS
MORE CUT OFF SYSTEM THE BOOT EASTWARD.
GIVEN THE RECENT VARIABILITY IN MODEL SOLUTIONS AND THEIR PROPENSITY
TO STRUGGLE HANDLING CLOSED LOWS...PARTICULARLY FEATURES DETACHED
FROM THE MAIN BELT OF WESTERLIES LIKE THIS ONE SHOULD BE...FORECAST
CONFIDENCE IS VERY LOW SATURDAY INTO EARLY NEXT WEEK. IN LINE WITH
THE LATEST GUIDANCE HAVE BEGUN TO TREND POPS A BIT LOWER OVER THE
WEEKEND...THOUGH ONLY MADE MODEST ADJUSTMENTS DOWNWARD GIVEN THE LOW
FORECAST CONFIDENCE. IF CURRENT TRENDS PERSIST...THEN MUCH OF THE
UPCOMING WEEKEND COULD POTENTIALLY END UP BEING DRY...BUT WILL LET
LATER SHIFTS MAKE ANY MORE SUBSTANTIAL CHANGES TO PRECIP CHANCES.
COMBINATION OF THE EASTWARD MOVING CLOSED LOW SOMEWHERE IN THE
REGION FOLLOWED BY NORTHERN STREAM SHORTWAVE THAT BOOTS OUT THE UPPER
LOW...HAVE TO MAINTAIN POPS ON A DAILY BASIS THROUGH THE REST OF THE
EXTENDED NEXT WEEK.
TEMPERATURE-WISE...TREND SHOULD BE TOWARD WARMING UP TO MORE
SEASONABLE LEVELS...THOUGH A WEAK IL SHORE LAKE BREEZE COULD PROVIDE
A BIT OF COOLING FRIDAY BEFORE STRONGER OFFSHORE GRADIENT BRINGS THE
WARMTH AND INCREASED HUMIDITY TO THE LAKEFRONT SATURDAY AFTERNOON.
BY SUNDAY INTO EARLY NEXT WEEK...SURFACE REFLECTION OF THE CUT OFF
LOW WILL DEVELOP TO OUR SOUTHWEST WHICH SHOULD RESULT IN MORE OF AN
ONSHORE COMPONENT WITH SOME ATTENDANT LAKE COOLING...THOUGH INLAND
TEMPS LOOK TO REMAIN SEASONABLY WARM.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* NORTHEAST WINDS AROUND 10 KT AT TIMES THIS AFTERNOON
KMD
//DISCUSSION...UPDATED 18Z...
FAIRLY QUIET CONDITIONS ACROSS THE TERMINALS THIS AFTERNOON...JUST
SOME SCATTERED AFTERNOON CUMULUS DEVELOPMENT AND NORTH TO
NORTHEAST WINDS AT 10 KT OR LESS AS HIGH PRESSURE CONTINUES TO
PUSH SOUTH. THE HIGH SPREADS OVERHEAD TONIGHT RESULTING IN LIGHT
AND VARIABLE WINDS ...THEN AS HIGH PRESSURE SLOWLY SHIFTS
EAST FRIDAY...WINDS WILL TURN SOUTHWESTERLY THROUGH THE DAY. WINDS
SHOULD GENERALLY REMAIN UNDER 10 KT...POSSIBLY GETTING CLOSE LATE
IN THE DAY. CURRENT FEELING IS IF THERE IS ANY LAKE BREEZE IT WOULD BE
CONFINED IN FAR NORTHEAST ILLINOIS AND NEAR THE SHORE. VFR
CONDITIONS THROUGH THE PERIOD.
KMD
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH IN ALL ELEMENTS
KMD
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT THROUGH WEDNESDAY...PERIODIC CHANCES FOR TSRA.
PRIMARILY VFR.
BMD
&&
.MARINE...
319 AM CDT
A COLD FRONT HAS DROPPED SOUTH ACROSS LAKE MICHIGAN OVERNIGHT WITH
MODERATE NORTHERLY FLOW IN THE WAKE OF THE FRONT. HIGH PRESSURE
CURRENTLY CENTERED OVER ONTARIO WILL BUILD SOUTH THROUGH THE DAY
ALLOWING WINDS TO GRADUALLY DIMINISH...BUT WITH COLD ADVECTION AND
MODERATE WINDS...SIGNIFICANT WAVE HEIGHTS IN THE 4 TO 6 FT RANGE
ARE EXPECTED TO PERSIST THROUGH THE MORNING BEFORE TAPERING SOME
MIDDAY. WINDS WILL BEGIN TO TURN SOUTHERLY THROUGH THE DAY FRIDAY
INTO SATURDAY AS THE HIGH MOVES OVER THE UPPER OHIO VALLEY.
ANOTHER COLD FRONT IS EXPECTED TO DROP ACROSS LAKE MICHIGAN
SATURDAY INTO SATURDAY NIGHT.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014 UNTIL 7 PM THURSDAY.
IN...BEACH HAZARDS STATEMENT...INZ001-INZ002 UNTIL 7 PM THURSDAY.
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
1213 PM CDT Thu Aug 14 2014
.UPDATE...
ISSUED AT 952 AM CDT THU AUG 14 2014
Cold front was located roughly along the I-74 corridor this
morning, where winds shift from northwest to northeast. No
significant temperature difference immediately along the front,
but much drier dew points (upper 40s/lower 50s) are upstream in
northeast Illinois. Latest HRRR continues to show some very light
showers/sprinkles speckled along the front during the afternoon,
which has already been accounted for in the hourly weather grids.
Little change was needed to the existing grids, except to lower
the dew points across the northeast CWA as the drier air moves in
from the northeast.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 328 AM CDT THU AUG 14 2014
Another spoke of energy is pivoting around the pesky upper low over
eastern Canada. This particular wave of interest is diving across
the western Great Lakes, and is helping to push a weak frontal
boundary south across Illinois. In the latest surface analysis, this
surface boundary lies in the vicinity of the I-74 corridor across
central Illinois. While this boundary is weak and moisture starved,
a main concern today is if it will successfully produce any rainfall.
Some spotty showers have been along the boundary through the night,
although a more notable impact has been a thick band of AC. Much of
the model guidance has been insisting for days that some rainfall
will accompany this front today, and even some of the short-term
mesoscale models are now doing the same. Still, given what has
occurred upstream, and progged moisture profiles in local forecast
soundings, have a hard time believing we`ll see more than virga
and/or sprinkles. So, plan to keep PoPs below the measurable rain
threshold today (15%), but will mention a slight chance of sprinkles
accompanying the front as it sinks south. The front pretty much
washes out by tonight, so do not expect the risk of sprinkles to
extend beyond this afternoon. Below normal temperatures will
continue through tonight, especially as you head north/east of the
decaying front.
&&
.LONG TERM...(Friday through Wednesday)
ISSUED AT 328 AM CDT THU AUG 14 2014
The nice stretch of summer weather will continue through Friday
evening with most areas staying dry and temperate as 1018 mb surface
high pressure ridge settles east of IL into the Ohio river valley on
Friday. Partly sunny skies expected on Friday with highs mostly in
the lower 80s and dew points elevating into the low to mid 60s Friday
afternoon with SSE winds 5-10 mph.
Most models now keep central/SE IL dry Friday evening with some qpf
moving into mainly western areas after midnight Friday night as
short waves eject east from the central Rockies across the MO
valley. Better chance of showers and thunderstorms to spread further
east during Saturday especially Saturday afternoon into Saturday
night. SPC has slight risk of severe storms Saturday SW of central
IL CWA but 5% risk of hail/wind as far NE as I-74 due to increase
wind shear and instability as dew points rise into the upper 60s to
around 70F by Sat afternoon.
Northwest upper level flow will become more zonal early next week as
upper level trof/low moves into IL. Weather to be more unsettled
from this weekend into at least early next work week. Models still
differ on timing of this feature but currently have daily chances of
showers and thunderstorms from this weekend through early next work
week with highest chances Saturday night through Monday. Tropical
humidity will return to IL during this weekend and linger into next
work week as dew points climb into the upper 60s and lower 70s. Highs
80-85F this weekend and Monday will climb into the mid to upper 80s
by middle of next week with a few spots in SW areas approaching 90.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 1212 PM CDT THU AUG 14 2014
VFR conditions expected through the period. Weak surface boundary
located roughly along a KPIA-KCMI line to sink a bit further south
this afternoon, before washing out. High-resolution models
continue to show very light showers/sprinkles through the
afternoon along the boundary, so will maintain the VCSH mention
for a few more hours. Skies expected to mainly be clear overnight
with high pressure nearly overhead, with some high clouds
spreading in from the northwest late. Winds behind the front this
afternoon will mainly be from the northeast, but trend more
northwest to northeast along the front itself. By late Friday
morning, a more consistent east-southeast flow is on tap.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEELHART
SHORT TERM...BAK
LONG TERM...07
AVIATION...GEELHART
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1229 PM CDT THU AUG 14 2014
.SHORT TERM /TODAY/...
ISSUED AT 340 AM CDT THU AUG 14 2014
RIDGE OF HIGH PRESSURE OVER THE NORTHERN GREAT LAKES AND SOUTHERN
CANADA WILL HOLD FOR ANOTHER DAY TODAY AS IT SLOWLY DRIFTS EAST.
PATCHY FOG...A FEW AREAS OF DENSE FOG THIS MORNING SHOULD LIFT
QUICKLY BY 13Z SHORTLY AFT SUNRISE. LOW PRESSURE OVER THE CENTRAL
ROCKIES WILL MOVE LITTLE THROUGH THIS AFTERNOON. HOWEVER...A WARM
FRONT STRETCHING EAST SOUTHEAST FROM THE LOW OVER SOUTHERN KANSAS
WILL BEGIN TO LIFT NORTH DURING THE AFTERNOON INTO NORTHERN
KANSAS. WARM AIR ADVECTION ALOFT AND A WEAK WAVE WILL CONTINUE AN
AREA OF SHOWERS AND THUNDERSTORMS OVER SOUTH DAKOTA WHICH SHOULD
GENERALLY REMAIN NORTHWEST OF THE REGION THROUGH LATE TODAY.
CIRRUS CONTINUE TO SPILL OVER THE H700 RIDGE TONIGHT...AND EXPECT
SOME HIGH CLOUDS TO CROSS THE REGION THIS AFTERNOON AND TONIGHT.
BY LATE AFTERNOON THERE WILL BE A SLIGHT CHANCE OF SHOWERS AND ISO
THUNDER FAR NORTHWEST AS THE NORTHERN STREAM SHORTWAVE APPROACHES
THE AREA. BOTH SYNOPTIC SCALE MODELS AND THE HRRR INCREASE FORCING
ACROSS THE FAR NORTHWEST THIS AFTERNOON. HIGHS TODAY WITH THE
POTENTIAL FOR MORE CLOUDS NORTHWEST AND INCREASING HIGH CLOUDS
ELSEWHERE...SHOULD HOLD HIGHS IN THE UPPER 70S TO LOWER 80S REGION
WIDE.
.LONG TERM /TONIGHT THROUGH WEDNESDAY/...
ISSUED AT 340 AM CDT THU AUG 14 2014
THE FIRST WAVE ARRIVES TONIGHT WITH MOISTURE INCREASING ALOFT INTO
AN UPPER LEVEL BOUNDARY ACROSS THE REGION. MODELS CONTINUE TO SHOW
INCREASING THETAE ADVECTION FROM 00Z TO 12Z FRIDAY OVER THE FORECAST
AREA. FLOW AT H850 REMAINS WEAK WITH SLOWLY EXITING HIGH PRESSURE TO
THE EAST. THIS WILL ALLOW ANY CONVECTION TO GRADUALLY WEAKEN
OVERNIGHT AS IT PUSHES ACROSS THE NORTHEAST WITH SHOWERS AND PERHAPS
ISOLATED THUNDER THROUGH FRIDAY MORNING. BY FRIDAY AFTERNOON...
DAYTIME HEATING...INCREASED MOISTURE TRANSPORT AND STRENGTHENING
H850 WINDS SHOULD INCREASE THE SHOWERS AND THUNDERSTORM ACTIVITY
OVER THE AREA ACROSS THE NORTHEAST AND SOUTHWEST. RAINFALL AMOUNTS
WILL REMAIN LIGHT THROUGH FRIDAY AFTERNOON. BY 00Z SATURDAY THE
MODELS ARE IN GENERALLY GOOD AGREEMENT HAVING THE WARM FRONT NEAR
THE IA MO BORDER AS AN H850 LOW APPROACHES WITH ANOTHER PUSH OF
STRONGER THETAE ADVECTION...H850 WINDS TO 25KT INCREASING TO 40KTS
BY 06Z OVER THE SOUTH. WITH THE STRONG FORCING AND BOUNDARY ALOFT...
THERE IS AN INCREASING CHANCE FOR AN MCS TO FORM OVER NORTHWEST MO
AND LIFT EAST NORTHEAST INTO SOUTHERN IOWA THROUGH THE NIGHT. BUFKIT
SOUNDINGS OVER SOUTHERN IOWA INDICATE SATURATION FROM H800 TO H300.
PRECIPITABLE WATER VALUES INCREASE TO 2 TO 2.25 INCHES BY 06-12Z
SATURDAY OVER SOUTHERN IOWA. AS WELL...WARM CLOUD DEPTHS TO 14 TO
15KFT DURING THIS TIME. THIS SHOULD PROMOTE VERY EFFICIENT RAINFALL
ACROSS THE BOUNDARY WITH ELEVATED CONVECTION. WITH INSTABILITY
VALUES DECREASING OVERNIGHT... THE MAIN CONCERN WILL BE HEAVY
RAINFALL. WITH THE FORECAST PARAMETERS...THERE IS A POTENTIAL FOR 2
TO +3 INCH TOTALS WITH ANY MCS THAT DEVELOPS. WILL CONTINUE TO
REFINE DETAILS OVER THE NEXT SEVERAL PACKAGES. AS THE CONVECTION
PULLS EAST SATURDAY MORNING THE UPPER LEVEL LOW WILL SLOWLY DRIFT
EAST. THIS WILL KEEP SHOWERS AND SCT THUNDER IN THE FORECAST FOR
SATURDAY. HIGHS FRIDAY WILL BE IN THE 70S TO LOWER 80S WITH THE
COOLER READINGS OVER THE NORTH. SATURDAY WILL SEE A MORE UNIFORM DAY
WITH MOST AREAS NEAR 80 FOR THE AFTERNOON AS CLOUD COVER AND THE
CHANCE FOR RAIN HOLDS. DEW POINTS WILL BE CLIMBING OVER THE NEXT
SEVERAL DAYS...WITH MORE UNCOMFORTABLE CONDITIONS EXPECTED. THE
SHOWER AND THUNDERSTORM POTENTIAL WILL LAST INTO SUNDAY AS THE UPPER
LEVEL SYSTEM PULLS EAST OF THE REGION. ON MONDAY THE AREA SHOULD BE
IN BETWEEN SYSTEMS WITH LITTLE CHANCE FOR ANY RAIN CENTRAL...SLIGHT
CHANCES EAST AND WEST. THE NEXT NORTHERN STREAM WAVE RETURNS FOR
MONDAY NIGHT AND TUESDAY WITH ANOTHER WARM FRONT ADVANCING EAST
ACROSS THE REGION. THIS SHOULD BRING AN ADDITIONAL CHANCE FOR SOME
THUNDERSTORMS MONDAY NIGHT AND TUESDAY WITH WARMER TEMPERATURES FOR
WEDNESDAY. IN FACT...H850 TEMPS ARE EXPECTED TO INCREASE TO 20C BY
WEDNESDAY WITH HIGHS IN THE MID 80S AND DEW POINTS BACK NEAR 70.
&&
.AVIATION...14/18Z
ISSUED AT 1229 PM CDT THU AUG 14 2014
VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD. WIDELY
SCATTERED SHRA/TSRA ARE EXPECTED TO DEVELOP ON FRIDAY...MAINLY
AFTER 12Z...WITH ASSOCIATED LOCALIZED MVFR OR LOWER CONDITIONS
POSSIBLE.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...REV
LONG TERM...REV
AVIATION...LEE
AREA FORECAST DISCUSSION
NWS DES MOINES IA
637 AM CDT THU AUG 14 2014
.SHORT TERM /TODAY/...
ISSUED AT 340 AM CDT THU AUG 14 2014
RIDGE OF HIGH PRESSURE OVER THE NORTHERN GREAT LAKES AND SOUTHERN
CANADA WILL HOLD FOR ANOTHER DAY TODAY AS IT SLOWLY DRIFTS EAST.
PATCHY FOG...A FEW AREAS OF DENSE FOG THIS MORNING SHOULD LIFT
QUICKLY BY 13Z SHORTLY AFT SUNRISE. LOW PRESSURE OVER THE CENTRAL
ROCKIES WILL MOVE LITTLE THROUGH THIS AFTERNOON. HOWEVER...A WARM
FRONT STRETCHING EAST SOUTHEAST FROM THE LOW OVER SOUTHERN KANSAS
WILL BEGIN TO LIFT NORTH DURING THE AFTERNOON INTO NORTHERN
KANSAS. WARM AIR ADVECTION ALOFT AND A WEAK WAVE WILL CONTINUE AN
AREA OF SHOWERS AND THUNDERSTORMS OVER SOUTH DAKOTA WHICH SHOULD
GENERALLY REMAIN NORTHWEST OF THE REGION THROUGH LATE TODAY.
CIRRUS CONTINUE TO SPILL OVER THE H700 RIDGE TONIGHT...AND EXPECT
SOME HIGH CLOUDS TO CROSS THE REGION THIS AFTERNOON AND TONIGHT.
BY LATE AFTERNOON THERE WILL BE A SLIGHT CHANCE OF SHOWERS AND ISO
THUNDER FAR NORTHWEST AS THE NORTHERN STREAM SHORTWAVE APPROACHES
THE AREA. BOTH SYNOPTIC SCALE MODELS AND THE HRRR INCREASE FORCING
ACROSS THE FAR NORTHWEST THIS AFTERNOON. HIGHS TODAY WITH THE
POTENTIAL FOR MORE CLOUDS NORTHWEST AND INCREASING HIGH CLOUDS
ELSEWHERE...SHOULD HOLD HIGHS IN THE UPPER 70S TO LOWER 80S REGION
WIDE.
.LONG TERM /TONIGHT THROUGH WEDNESDAY/...
ISSUED AT 340 AM CDT THU AUG 14 2014
THE FIRST WAVE ARRIVES TONIGHT WITH MOISTURE INCREASING ALOFT INTO
AN UPPER LEVEL BOUNDARY ACROSS THE REGION. MODELS CONTINUE TO SHOW
INCREASING THETAE ADVECTION FROM 00Z TO 12Z FRIDAY OVER THE FORECAST
AREA. FLOW AT H850 REMAINS WEAK WITH SLOWLY EXITING HIGH PRESSURE TO
THE EAST. THIS WILL ALLOW ANY CONVECTION TO GRADUALLY WEAKEN
OVERNIGHT AS IT PUSHES ACROSS THE NORTHEAST WITH SHOWERS AND PERHAPS
ISOLATED THUNDER THROUGH FRIDAY MORNING. BY FRIDAY AFTERNOON...
DAYTIME HEATING...INCREASED MOISTURE TRANSPORT AND STRENGTHENING
H850 WINDS SHOULD INCREASE THE SHOWERS AND THUNDERSTORM ACTIVITY
OVER THE AREA ACROSS THE NORTHEAST AND SOUTHWEST. RAINFALL AMOUNTS
WILL REMAIN LIGHT THROUGH FRIDAY AFTERNOON. BY 00Z SATURDAY THE
MODELS ARE IN GENERALLY GOOD AGREEMENT HAVING THE WARM FRONT NEAR
THE IA MO BORDER AS AN H850 LOW APPROACHES WITH ANOTHER PUSH OF
STRONGER THETAE ADVECTION...H850 WINDS TO 25KT INCREASING TO 40KTS
BY 06Z OVER THE SOUTH. WITH THE STRONG FORCING AND BOUNDARY ALOFT...
THERE IS AN INCREASING CHANCE FOR AN MCS TO FORM OVER NORTHWEST MO
AND LIFT EAST NORTHEAST INTO SOUTHERN IOWA THROUGH THE NIGHT. BUFKIT
SOUNDINGS OVER SOUTHERN IOWA INDICATE SATURATION FROM H800 TO H300.
PRECIPITABLE WATER VALUES INCREASE TO 2 TO 2.25 INCHES BY 06-12Z
SATURDAY OVER SOUTHERN IOWA. AS WELL...WARM CLOUD DEPTHS TO 14 TO
15KFT DURING THIS TIME. THIS SHOULD PROMOTE VERY EFFICIENT RAINFALL
ACROSS THE BOUNDARY WITH ELEVATED CONVECTION. WITH INSTABILITY
VALUES DECREASING OVERNIGHT... THE MAIN CONCERN WILL BE HEAVY
RAINFALL. WITH THE FORECAST PARAMETERS...THERE IS A POTENTIAL FOR 2
TO +3 INCH TOTALS WITH ANY MCS THAT DEVELOPS. WILL CONTINUE TO
REFINE DETAILS OVER THE NEXT SEVERAL PACKAGES. AS THE CONVECTION
PULLS EAST SATURDAY MORNING THE UPPER LEVEL LOW WILL SLOWLY DRIFT
EAST. THIS WILL KEEP SHOWERS AND SCT THUNDER IN THE FORECAST FOR
SATURDAY. HIGHS FRIDAY WILL BE IN THE 70S TO LOWER 80S WITH THE
COOLER READINGS OVER THE NORTH. SATURDAY WILL SEE A MORE UNIFORM DAY
WITH MOST AREAS NEAR 80 FOR THE AFTERNOON AS CLOUD COVER AND THE
CHANCE FOR RAIN HOLDS. DEW POINTS WILL BE CLIMBING OVER THE NEXT
SEVERAL DAYS...WITH MORE UNCOMFORTABLE CONDITIONS EXPECTED. THE
SHOWER AND THUNDERSTORM POTENTIAL WILL LAST INTO SUNDAY AS THE UPPER
LEVEL SYSTEM PULLS EAST OF THE REGION. ON MONDAY THE AREA SHOULD BE
IN BETWEEN SYSTEMS WITH LITTLE CHANCE FOR ANY RAIN CENTRAL...SLIGHT
CHANCES EAST AND WEST. THE NEXT NORTHERN STREAM WAVE RETURNS FOR
MONDAY NIGHT AND TUESDAY WITH ANOTHER WARM FRONT ADVANCING EAST
ACROSS THE REGION. THIS SHOULD BRING AN ADDITIONAL CHANCE FOR SOME
THUNDERSTORMS MONDAY NIGHT AND TUESDAY WITH WARMER TEMPERATURES FOR
WEDNESDAY. IN FACT...H850 TEMPS ARE EXPECTED TO INCREASE TO 20C BY
WEDNESDAY WITH HIGHS IN THE MID 80S AND DEW POINTS BACK NEAR 70.
&&
.AVIATION...14/12Z
ISSUED AT 631 AM CDT THU AUG 14 2014
FEW CONCERNS FOR TODAY. PATHCY FOG STILL EVIDENT AT
KOTM...OTHERWISE SHOULD BE BACK TO VFR BY 13Z. HIGH CLOUDS RIDING
RIDGE WILL GLIDE ACROSS AREA TODAY WITH SCT CLOUDS AFT 17Z. WARM
AIR ADVECTION CONVECTION/SHOWERS AFT 03Z TO AFFECT NORTHWEST AREAS
BUT CONFIDENCE ON COVERAGE REMAINS LOW. HAVE ADDED VCSH TO KFOD
AND KMCW FOR NOW AFT 03-08Z. THIS WILL SLIDE ESE BY 12Z FRIDAY./REV
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...REV
LONG TERM...REV
AVIATION...REV
AREA FORECAST DISCUSSION
NWS DES MOINES IA
341 AM CDT THU AUG 14 2014
.SHORT TERM /TODAY/...
ISSUED AT 340 AM CDT THU AUG 14 2014
RIDGE OF HIGH PRESSURE OVER THE NORTHERN GREAT LAKES AND SOUTHERN
CANADA WILL HOLD FOR ANOTHER DAY TODAY AS IT SLOWLY DRIFTS EAST.
PATCHY FOG...A FEW AREAS OF DENSE FOG THIS MORNING SHOULD LIFT
QUICKLY BY 13Z SHORTLY AFT SUNRISE. LOW PRESSURE OVER THE CENTRAL
ROCKIES WILL MOVE LITTLE THROUGH THIS AFTERNOON. HOWEVER...A WARM
FRONT STRETCHING EAST SOUTHEAST FROM THE LOW OVER SOUTHERN KANSAS
WILL BEGIN TO LIFT NORTH DURING THE AFTERNOON INTO NORTHERN
KANSAS. WARM AIR ADVECTION ALOFT AND A WEAK WAVE WILL CONTINUE AN
AREA OF SHOWERS AND THUNDERSTORMS OVER SOUTH DAKOTA WHICH SHOULD
GENERALLY REMAIN NORTHWEST OF THE REGION THROUGH LATE TODAY.
CIRRUS CONTINUE TO SPILL OVER THE H700 RIDGE TONIGHT...AND EXPECT
SOME HIGH CLOUDS TO CROSS THE REGION THIS AFTERNOON AND TONIGHT.
BY LATE AFTERNOON THERE WILL BE A SLIGHT CHANCE OF SHOWERS AND ISO
THUNDER FAR NORTHWEST AS THE NORTHERN STREAM SHORTWAVE APPROACHES
THE AREA. BOTH SYNOPTIC SCALE MODELS AND THE HRRR INCREASE FORCING
ACROSS THE FAR NORTHWEST THIS AFTERNOON. HIGHS TODAY WITH THE
POTENTIAL FOR MORE CLOUDS NORTHWEST AND INCREASING HIGH CLOUDS
ELSEWHERE...SHOULD HOLD HIGHS IN THE UPPER 70S TO LOWER 80S REGION
WIDE.
.LONG TERM /TONIGHT THROUGH WEDNESDAY/...
ISSUED AT 340 AM CDT THU AUG 14 2014
THE FIRST WAVE ARRIVES TONIGHT WITH MOISTURE INCREASING ALOFT INTO
AN UPPER LEVEL BOUNDARY ACROSS THE REGION. MODELS CONTINUE TO SHOW
INCREASING THETAE ADVECTION FROM 00Z TO 12Z FRIDAY OVER THE FORECAST
AREA. FLOW AT H850 REMAINS WEAK WITH SLOWLY EXITING HIGH PRESSURE TO
THE EAST. THIS WILL ALLOW ANY CONVECTION TO GRADUALLY WEAKEN
OVERNIGHT AS IT PUSHES ACROSS THE NORTHEAST WITH SHOWERS AND PERHAPS
ISOLATED THUNDER THROUGH FRIDAY MORNING. BY FRIDAY AFTERNOON...
DAYTIME HEATING...INCREASED MOISTURE TRANSPORT AND STRENGTHENING
H850 WINDS SHOULD INCREASE THE SHOWERS AND THUNDERSTORM ACTIVITY
OVER THE AREA ACROSS THE NORTHEAST AND SOUTHWEST. RAINFALL AMOUNTS
WILL REMAIN LIGHT THROUGH FRIDAY AFTERNOON. BY 00Z SATURDAY THE
MODELS ARE IN GENERALLY GOOD AGREEMENT HAVING THE WARM FRONT NEAR
THE IA MO BORDER AS AN H850 LOW APPROACHES WITH ANOTHER PUSH OF
STRONGER THETAE ADVECTION...H850 WINDS TO 25KT INCREASING TO 40KTS
BY 06Z OVER THE SOUTH. WITH THE STRONG FORCING AND BOUNDARY ALOFT...
THERE IS AN INCREASING CHANCE FOR AN MCS TO FORM OVER NORTHWEST MO
AND LIFT EAST NORTHEAST INTO SOUTHERN IOWA THROUGH THE NIGHT. BUFKIT
SOUNDINGS OVER SOUTHERN IOWA INDICATE SATURATION FROM H800 TO H300.
PRECIPITABLE WATER VALUES INCREASE TO 2 TO 2.25 INCHES BY 06-12Z
SATURDAY OVER SOUTHERN IOWA. AS WELL...WARM CLOUD DEPTHS TO 14 TO
15KFT DURING THIS TIME. THIS SHOULD PROMOTE VERY EFFICIENT RAINFALL
ACROSS THE BOUNDARY WITH ELEVATED CONVECTION. WITH INSTABILITY
VALUES DECREASING OVERNIGHT... THE MAIN CONCERN WILL BE HEAVY
RAINFALL. WITH THE FORECAST PARAMETERS...THERE IS A POTENTIAL FOR 2
TO +3 INCH TOTALS WITH ANY MCS THAT DEVELOPS. WILL CONTINUE TO
REFINE DETAILS OVER THE NEXT SEVERAL PACKAGES. AS THE CONVECTION
PULLS EAST SATURDAY MORNING THE UPPER LEVEL LOW WILL SLOWLY DRIFT
EAST. THIS WILL KEEP SHOWERS AND SCT THUNDER IN THE FORECAST FOR
SATURDAY. HIGHS FRIDAY WILL BE IN THE 70S TO LOWER 80S WITH THE
COOLER READINGS OVER THE NORTH. SATURDAY WILL SEE A MORE UNIFORM DAY
WITH MOST AREAS NEAR 80 FOR THE AFTERNOON AS CLOUD COVER AND THE
CHANCE FOR RAIN HOLDS. DEW POINTS WILL BE CLIMBING OVER THE NEXT
SEVERAL DAYS...WITH MORE UNCOMFORTABLE CONDITIONS EXPECTED. THE
SHOWER AND THUNDERSTORM POTENTIAL WILL LAST INTO SUNDAY AS THE UPPER
LEVEL SYSTEM PULLS EAST OF THE REGION. ON MONDAY THE AREA SHOULD BE
IN BETWEEN SYSTEMS WITH LITTLE CHANCE FOR ANY RAIN CENTRAL...SLIGHT
CHANCES EAST AND WEST. THE NEXT NORTHERN STREAM WAVE RETURNS FOR
MONDAY NIGHT AND TUESDAY WITH ANOTHER WARM FRONT ADVANCING EAST
ACROSS THE REGION. THIS SHOULD BRING AN ADDITIONAL CHANCE FOR SOME
THUNDERSTORMS MONDAY NIGHT AND TUESDAY WITH WARMER TEMPERATURES FOR
WEDNESDAY. IN FACT...H850 TEMPS ARE EXPECTED TO INCREASE TO 20C BY
WEDNESDAY WITH HIGHS IN THE MID 80S AND DEW POINTS BACK NEAR 70.
&&
.AVIATION...14/06Z
ISSUED AT 1153 PM CDT WED AUG 13 2014
LITTLE CHANGE TO PREVIOUS THOUGHTS AS WIDESPREAD VFR CONDITIONS
WILL PERSIST FOR MUCH OF THE FORECAST PERIOD. SOME GROUND FOG WILL
BE POSSIBLE THROUGH DAYBREAK ON THURSDAY...BUT SHOULD REMAIN
RELATIVELY ISOLATED. ANY CEILINGS THAT DEVELOP THURSDAY INTO
THURSDAY EVENING WILL REMAIN VFR AND LIKELY AT OR ABOVE 12KFT.
LIGHT AND VARIABLE OVERNIGHT WINDS WILL BECOME LIGHT FROM THE
SOUTHEAST ON THURSDAY AS SURFACE RIDGE SLIDES EAST OF THE STATE.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...REV
LONG TERM...REV
AVIATION...COGIL
AREA FORECAST DISCUSSION
NWS TOPEKA KS
841 PM CDT Fri Aug 15 2014
.UPDATE...
Issued at 841 PM CDT FRI AUG 15 2014
Went ahead and added a mention of patchy fog to the forecast across
the northern tier of counties. Surface obs show an east to west
boundary across east central KS with dewpoints in the lower 70s
pooling north of this feature. With no real dry air advection
anticipated, think there is a high enough prob for some patchy
fog. If skies clear out, may have to update again to increase the
coverage and possibly the opacity of the fog.
&&
.SHORT TERM...(This Evening through Saturday)
Issued at 336 PM CDT FRI AUG 15 2014
Weak shortwave trough preceded by last nights MCV currently moving
eastward along the KS/NE border in north central Kansas will provide
the lift for more showers and embedded thunderstorms into the
evening...mainly across the northeast 1/3 of the CWA...then more
scattered/isolated southward. Thunderstorms most likely to produce
locally strong wind gusts will be in closer proximity to the upper
80s/near 90 degree heat south of I 35...that is if thunderstorms are
able to develop that far south and east in the CWA. Otherwise precip
chances will steadily decrease later tonight across the entire area.
If clouds are less extensive over the north central...then some
patchy fog will be possible in that area following today`s rainfall.
As drier air works into the northwest CWA later tonight behind the
front...lows could fall into the middle 60s...with the lower 70s
south and eastward. As the current shortwave turns more east
southeast on Saturday...higher chances for more convection will be
east of the CWA...although will maintain a low end chance/slight
chance pop. More clouds across the northeast corner will aid cooler
highs in the middle 80s...with lower 90s across the southern CWA.
.LONG TERM...(Saturday Night through Friday)
Issued at 336 PM CDT FRI AUG 15 2014
Showers and isolated thunderstorms may linger into the evening hours
on Saturday as the upper trough moves through. This will be followed
by a period of subsidence, however another wave is depicted to move
south along the Missouri River and by Sunday may bring a small
chance of precipitation in the eastern counties. Expect most of the
area to remain dry Sunday evening before forcing increases ahead of
an upper level trough moving southeast across the Northern and
Central Plains after midnight Sunday. The upper trough will move
through on Monday and Monday evening bringing a frontal boundary
through the CWA. Boundary looks to hang up across southeast or east
central Kansas on Tuesday and will leave small precipitation
chances during the day along and south of I-35.
Tuesday night through Friday will see periodic waves move through
the Central Plains as we transition from a northwest flow to a
southwest upper flow by the end of next week. Timing is difficult
and will maintain chances of precipitation from Tuesday night
through Thursday. Friday looking dry with rising heights aloft.
Highs Sunday through Wednesday are expected to range from the upper
80s to lower 90s then warming into the mid 90s Thursday and Friday.
Lows will be on the mild side with upper 60s to middle 70s
expected.
&&
.AVIATION...(For the 00Z TAFs through 00Z Saturday Evening)
Issued at 612 PM CDT FRI AUG 15 2014
Models continue to struggle with the elevated SHRA so confidence
in the forecast is below average. Fortunately the impacts should
be confined to a brief reduction to MVFR VSBY within the heavier
SHRA. The 23Z water vapor and profiler data suggests a weak
shortwave is overhead now. Think that this feature should continue
to propagate southeast this evening with general subsidence
gradually increasing and that the RAP is overdoing the QPF by
hanging onto isentropic ascent to long. The HRRR seems to have as
good as any depiction on the current precip. With no real
development going on over northwestern KS or southern NEB, think
the light radar returns north of MHK represent the back edge of
the shortwave and have timed this feature out to bring an end to a
mention of precip. Of course if skies clear out, the chances for
ground fog will increase. Will have to monitor clouds this evening
to see if fog should be added to the forecast.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...Wolters
SHORT TERM...63
LONG TERM...53
AVIATION...Wolters
AREA FORECAST DISCUSSION
NWS TOPEKA KS
612 PM CDT Fri Aug 15 2014
...AVIATION UPDATE...
.SHORT TERM...(This Evening through Saturday)
Issued at 336 PM CDT FRI AUG 15 2014
Weak shortwave trough preceded by last nights MCV currently moving
eastward along the KS/NE border in north central Kansas will provide
the lift for more showers and embedded thunderstorms into the
evening...mainly across the northeast 1/3 of the CWA...then more
scattered/isolated southward. Thunderstorms most likely to produce
locally strong wind gusts will be in closer proximity to the upper
80s/near 90 degree heat south of I 35...that is if thunderstorms are
able to develop that far south and east in the CWA. Otherwise precip
chances will steadily decrease later tonight across the entire area.
If clouds are less extensive over the north central...then some
patchy fog will be possible in that area following today`s rainfall.
As drier air works into the northwest CWA later tonight behind the
front...lows could fall into the middle 60s...with the lower 70s
south and eastward. As the current shortwave turns more east
southeast on Saturday...higher chances for more convection will be
east of the CWA...although will maintain a low end chance/slight
chance pop. More clouds across the northeast corner will aid cooler
highs in the middle 80s...with lower 90s across the southern CWA.
.LONG TERM...(Saturday Night through Friday)
Issued at 336 PM CDT FRI AUG 15 2014
Showers and isolated thunderstorms may linger into the evening hours
on Saturday as the upper trough moves through. This will be followed
by a period of subsidence, however another wave is depicted to move
south along the Missouri River and by Sunday may bring a small
chance of precipitation in the eastern counties. Expect most of the
area to remain dry Sunday evening before forcing increases ahead of
an upper level trough moving southeast across the Northern and
Central Plains after midnight Sunday. The upper trough will move
through on Monday and Monday evening bringing a frontal boundary
through the CWA. Boundary looks to hang up across southeast or east
central Kansas on Tuesday and will leave small precipitation
chances during the day along and south of I-35.
Tuesday night through Friday will see periodic waves move through
the Central Plains as we transition from a northwest flow to a
southwest upper flow by the end of next week. Timing is difficult
and will maintain chances of precipitation from Tuesday night
through Thursday. Friday looking dry with rising heights aloft.
Highs Sunday through Wednesday are expected to range from the upper
80s to lower 90s then warming into the mid 90s Thursday and Friday.
Lows will be on the mild side with upper 60s to middle 70s
expected.
&&
.AVIATION...(For the 00Z TAFs through 00Z Saturday Evening)
Issued at 612 PM CDT FRI AUG 15 2014
Models continue to struggle with the elevated SHRA so confidence
in the forecast is below average. Fortunately the impacts should
be confined to a brief reduction to MVFR VSBY within the heavier
SHRA. The 23Z water vapor and profiler data suggests a weak
shortwave is overhead now. Think that this feature should continue
to propagate southeast this evening with general subsidence
gradually increasing and that the RAP is overdoing the QPF by
hanging onto isentropic ascent to long. The HRRR seems to have as
good as any depiction on the current precip. With no real
development going on over northwestern KS or southern NEB, think
the light radar returns north of MHK represent the back edge of
the shortwave and have timed this feature out to bring an end to a
mention of precip. Of course if skies clear out, the chances for
ground fog will increase. Will have to monitor clouds this evening
to see if fog should be added to the forecast.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...63
LONG TERM...53
AVIATION...Wolters
AREA FORECAST DISCUSSION
NWS PADUCAH KY
205 PM CDT Thu Aug 14 2014
.UPDATE...
Issued at 201 PM CDT THU AUG 14 2014
For aviation section only.
UPDATE Issued at 630 am CDT THU AUG 14 2014
Updated for aviation forecast discussion.
&&
.SHORT TERM...(Today through Saturday)
Issued at 229 AM CDT THU AUG 14 2014
High pressure was centered over the region during the overnight
hours, with a frontal boundary draped across parts of IA, IL, IN and
into OH. Models have been advertising this back door cold front for
several days now. It will continue to sag southwest toward the area
today. A band of mid clouds is seen on satellite and METAR
observations/radar indicate that some spotty showers are resulting
from these clouds. The frontal boundary should reach parts of
southern IL and southwest IN by afternoon or early evening.
Models differ on whether precipitation develops into our CWA
however. The 00Z NAM and latest RUC keep the QPF just north of us,
while the GFS indicate a very small sliver of our northernmost
counties have a chance of seeing a few showers. Some of the hi res
models (ARW/NMM) show a band of spotty showers dropping into parts
of southern IL, southwest IN and parts of KY during the late
afternoon hours. Might opt to throw in some light showers or
sprinkles up in the far north since there may be just enough low
level moisture to bring a few drops to the ground. Will wait and see
what surrounding offices want to do.
Temperatures today should be in the lower to mid 80s, similar to
what occurred yesterday. However, it might be a bit warmer in parts
of SEMO today since winds will become more southerly there.
Whatever precipitation does occur later today should be short lived
as the front disintegrates and high pressure tries to build in behind
it tonight. On Friday, moisture begins to increase which will mean
an increase in cloudiness. Meanwhile, mid/upper heights will begin
rising by late in the week and into weekend, which will mean a bump
in temperatures. Sfc winds will also eventually shift around to the
south as well. We should see upper 80s area wide on Friday and
Saturday.
Next item of business is watching how a mid level short wave moves
across the top of a prominent ridge across the mid CONUS. It is
slated to drop southeast toward the area Friday night into Saturday.
We believe Friday night should be mainly dry but chances for rain
will have to be maintained at least in our northwestern sections for
Saturday. However, the better chances look to arrive Saturday night.
.LONG TERM...(Sunday through Wednesday)
Issued at 229 AM CDT THU AUG 14 2014
A blend of the 00z/12z GFS/GEFS and 12z ECENS was used for this
forecast. This resulted in little change to the inherited PoPs and
resultant temperatures. Temperatures will be geared toward MOS and
CONUS raw model output.
Slow moving upper trof is forecast to approach the CWFA Saturday
night and slowly progress ESE across the region through Sunday
night. Will carry good chance PoPs for convection as a result given
the respectable moisture coupled with mid trop forcing that will
accompany the upper system.
The system will head on to the east Monday. Will linger chance PoPs
over the east, and taper them off west. We may see a lull Monday
night as weak s/wv ridging moves overhead. Inherited 20% values and
see no reason to drop them yet, until a more clear signal is
established.
As some deamplification of the pattern occurs, the WNW flow pattern
across the area will weaken. We will be in broad SSW surface slow as
broad low pressure develops over the plains. Little to key in on
feature wise. The models continue to develop QPF over the region in
what should be a weak but unsettled mid trop flow pattern. Therefore
will carry low chance PoPs during the day Tue/Wed, and taper them
off to slight chances at night.
&&
.AVIATION...
Issued at 201 PM CDT WED AUG 13 2014
Could see some MVFR fog development again on Friday morning.
Otherwise, high pressure will bring generally clear skies and
light winds through the TAF period.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1123 AM EDT THU AUG 14 2014
.UPDATE...
ISSUED AT 1120 AM EDT THU AUG 14 2014
SOME SPRINKLES AND LIGHT RAIN SHOWERS ARE WORKING ACROSS NORTHEASTERN
KY AND WILL AFFECT PARTS OF THE BIG SANDY REGION THROUGH EARLY
AFTERNOON. MID AND HIGH CLOUDS ARE WORKING ACROSS THE REMAINDER OF
THE CWA AND SHOULD THROUGH EARLY TO MID AFTERNOON. OTHERWISE...A COLD
FRONT IS APPROACHING THE REGION FROM THE NORTH AND IS NEARING THE OH
RIVER AT THIS TIME. THE BOUNDARY APPEARS TO CURRENTLY EXTEND FROM
JUST NEAR THE INTERSTATE 79 CORRIDOR FROM THE PIT AND LBE AREA SOUTH
THROUGH MGW AND CKB AND THEN WEST BETWEEN PKB AND CRW...NORTH OF HTS
AND BETWEEN DAY AND CVG AND THEN WEST AND NORTHWEST ACROSS CENTRAL IN
AND IL. SFC DEWPOINTS REMAIN NEAR 60 ACROSS MUCH OF THE AREA.
THE RECENT HRRR RUNS AS WELL AS THE 12Z NAM AND TO SOME EXTENT RECENT
RAP RUNS AND EVEN 6Z GFS SUPPORT SOME REDEVELOPMENT AS A SHORTWAVE
ROTATES THROUGH THE SOUTHERN GREAT LAKES REGION AND INTO THE OHIO
VALLEY AND SEND THE BOUNDARY DOWN INTO EASTERN KY. THE 9Z SREF ALSO
HAS SOME HIGHER POPS DURING THE AFTERNOON AND EVENING. WITH THIS IN
MIND...OPTED TO GO WITH SOME ISOLATED TO SCATTERED POPS LATER TODAY
FOR MUCH OF THE CENTRAL AND NORTHEAST PART OF THE CWA. THEN INTO THE
EVENING...WE OPTED TO CARRY ISOLATED POPS ACROSS THE CENTRAL...SOUTHEAST
PART OF THE AREA AS WELL AS THE SME AND LOZ AREAS. AS THIS ACTIVITY
BEGINS TO DEVELOP THIS AFTERNOON THIS MAY NEED SOME FINE TUNING.
ALONG WITH THIS...CLOUD COVER WAS INCREASED FOR MUCH OF THE REMAINDER
OF THE DAY AND INTO THE OVERNIGHT HOURS.
UPDATE ISSUED AT 745 AM EDT THU AUG 14 2014
THE FRONT IS SETTLING INTO THE AREA WITH SOME SPRINKLES ALREADY NOTED
ON RADAR NORTH OF INTERSTATE 64. HAVE ADDED THIS TO THE POP AND WX
GRIDS. THE FOG IS FOUND MAINLY IN THE VALLEYS THROUGH EAST KENTUCKY
WITH SOME LOCALLY DENSE PATCHES. DID ALSO FINE TUNE THE T/TD GRIDS
PER THE LATEST OBS AND TRENDS. THESE HAVE BEEN SENT TO THE NDFD AND
WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 315 AM EDT THU AUG 14 2014
06Z SFC ANALYSIS SHOWS WEAK HIGH PRESSURE THROUGH THE TENNESSEE
VALLEY WITH A MOSTLY DRY COLD FRONT TO OUR NORTH DROPPING SOUTH
THROUGH THE OHIO VALLEY. THIS HAS LEFT MOST OF EAST KENTUCKY UNDER
CLEAR SKIES WITH A DRY AIR MASS IN PLACE. COMBINED WITH LIGHT
WINDS...THE RADIATIVE COOLING IS HELPING TO DROP TEMPERATURES INTO
THE 50S THROUGH THE AREA. IN THE VALLEYS THESE TEMPS ARE GETTING
CLOSE TO THE DEWPOINTS RESULTING IN THE FORMATION OF FOG ALONG WITH
THE POTENTIAL FOR LOCALLY DENSE PATCHES. HAVE ALLOWED FOR THIS IN THE
GRIDS THROUGH 13Z. ASSOCIATED WITH THE DESCENDING FRONT TO THE
NORTH...A PATCH OF MID LEVEL CLOUDS ARE SETTING INTO NORTHERN
KENTUCKY AND THIS SHOULD LIMIT THE COOLING AND FOG FORMATION IN THOSE
PARTS THROUGH DAWN. THE AREAS OF DENSE FOG WILL BE HIGHLIGHTED IN THE
HWO FOR EARLY THIS MORNING.
THE MODELS ARE IN PRETTY GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM
PORTION OF THE FORECAST. THEY ALL DEPICT THE RESURGENCE OF THE
UNSEASONABLY DEEP ONTARIO UPPER LOW THROUGH THE DAY WITH ITS
SOUTHWARD PUSH OF ENERGY AND HEIGHT FALLS. THE BEST ENERGY WITH THIS
WILL STAY JUST NORTHEAST OF JKL THROUGH FRIDAY MORNING BEFORE THE LOW
GYRATES BACK FURTHER NORTH DURING THE DAY FRIDAY ALLOWING FOR RISING
HEIGHTS AND A DEPARTING ENERGY STREAM. WITH A SLIGHTLY SLOWER
MOVEMENT TO THE UPPER LOW...THE NAM KEEPS THE LOWER HEIGHTS IN THE
SOUTHERN OHIO VALLEY A BIT LONGER INTO THE DAY FRIDAY. HAVE FAVORED A
GENERAL MODEL BLEND GIVEN THE SIMILARITIES...THOUGH THE HIGHER
RESOLUTION HRRR AND NAM12 WERE GIVEN MORE EMPHASIS FOR THE FIRST
PART OF THE FORECAST.
SENSIBLE WEATHER WILL FEATURE ANOTHER PLEASANTLY COOL AND MOSTLY DRY
DAY UNDER PARTLY CLOUDY TO MOSTLY SUNNY SKIES. THE COLD FRONT WILL
SETTLE INTO NORTHERN PARTS OF THE CWA AND MAKE FOR A THREAT OF
SPRINKLES OR A STRAY SHOWER TODAY. THE MODEL FORECAST SOUNDINGS ARE
UNFAVORABLE FOR THUNDER WITH A MID LEVEL CAP AND LOW CAPE VALUES SO
HAVE KEPT OUT THUNDER FOR THE GRIDS. CANNOT RULE OUT A STRAY SHOWER
INTO THE NIGHT TONIGHT...BUT GIVEN THE LOSS OF DIURNAL HEATING WILL
KEEP IT DRY. AGAIN PATCHY FOG...LOCALLY DENSE...CAN BE ANTICIPATED IN
THE VALLEYS FOR FRIDAY MORNING...BUT PROBABLY NOT AS EXTENSIVE AS
THIS MORNING/S WILL LIKELY END UP. THE FRONT REMAINS AROUND INTO THE
DAY FRIDAY...BUT RISING HEIGHTS WILL KEEP THE RISK OF SPRINKLES OR
SHOWERS TO A MINIMUM...WHILE ANOTHER RELATIVELY COOL SUMMER DAY IS
HAD BY ALL.
USED THE CONSSHORT AS A STARTING POINT FOR THE T/TD/WIND GRIDS
THROUGH THE FIRST 24 HOURS AND THE SUPERBLEND THEREAFTER. DID MAKE
SOME ADJUSTMENTS TONIGHT FOR RIDGE AND VALLEY TEMPERATURE
DIFFERENCES. WITH THE POPS...ENDED UP A NOTCH HIGHER THAN MOS TODAY
AND TONIGHT FOR THE NORTHERN PARTS OF THE AREA...OWING TO THE
FRONT...WAS IN LINE WITH THE GUIDANCE ON FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 300 AM EDT THU AUG 14 2014
THE MODELS WERE STILL IN DECENT AGREEMENT IN THE EXTENDED. THE
OVERALL MID AND UPPER LEVEL PATTERNS ARE PROGGED TO FEATURE A RIDGE
OF HIGH PRESSURE WEAKENING AND RETREATING SOUTHEASTWARD OUT OF THE
OHIO AND TENNESSEE VALLEY REGIONS FRIDAY NIGHT AND SATURDAY. THIS
WILL ALLOW THE PERIOD TO START OUT DRY WITH INCREASING CLOUD COVER
AND LIGHT WINDS ON TAP FOR EASTERN KENTUCKY. THE CLOUD COVER WILL BE
IN RESPONSE TO AN AREA OF LOW PRESSURE AND ITS ASSOCIATED FRONTAL
BOUNDARY TAKING SHAPE OVER THE EAST CENTRAL PLAINS AND MOVING
EASTWARD TOWARD THE AREA SUNDAY AND SUNDAY NIGHT. THE INITIAL AREA
OF LOW PRESSURE LOOKS TO MOVE ACROSS THE AREA SUNDAY NIGHT. A
FRONTAL BOUNDARY EXTENDING FROM THIS LOW WILL STALL OUT ALONG THE
TENNESSEE VALLEY REGION EASTWARD TO THE EAST COAST OF THE CONUS. THE
PRESENCE OF THIS BOUNDARY WOULD KEEP A CHANCE OF SHOWERS AND STORMS
IN THE FORECAST FROM EARLY SUNDAY THROUGH THE END OF THE UPCOMING
WORK WEEK. WAVES OF LOW PRESSURE MOVING ALONG THE FRONT WOULD
PROVIDE THE LIFT NEEDED TO SPAWN SHOWERS AND STORMS AS MOISTURE FORM
THE GULF OF MEXICO RIDES UP AND OVER THE FRONT. THE ISSUE AT HAND
WILL BE THE TIMING OF THESE WAVES OF LOW PRESSURE AND HOW MUCH
MOISTURE THEY WILL HAVE TO TAP INTO. BASED ON THIS BIT OF
UNCERTAINTY...DECIDED TO KEEP PRECIPITATION CHANCES BETWEEN 20 AND
40 PERCENT ACROSS THE BOARD...FAVORING THE DAYTIME HOURS FOR PEAK
ACTIVITY WITH LULLS IN THE ACTION DURING THE NIGHTTIME PERIODS.
TEMPERATURES THROUGHOUT THE PERIOD SHOULD BE ABLE TO RECOVER TO
NORMAL VALUES FOR THIS TIME OF YEAR AS THE GULF OF MEXICO OPENS UP
AND WARM MOIST AIR INVADES THE REGION FROM THE SOUTH. HIGHS IN
GENERAL ARE EXPECTED TO BE IN THE MID 80S THROUGHOUT THE PERIOD WITH
OVERNIGHT LOWS IN THE UPPER 60S THE FIRST SEVERAL NIGHTS...TO AROUND
70 BY THE END OF THE WEEK. THE ONE EXCEPTION MIGHT BE FRIDAY NIGHT
BEFORE THE WINDS SHIFT TO THE SOUTH AND THE WARMER AIR FROM THE GULF
MAKES IT WAY INTO THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 810 AM EDT THU AUG 14 2014
THE IFR AND VLIFR FOG WILL BURN OFF BETWEEN 12 AND 13Z TODAY...
GIVING WAY QUICKLY TO VFR CONDITIONS AND LIGHT NORTHWEST WINDS THAT
WILL LAST THROUGH EVENING. EXPECT CALM WINDS AND PARTLY CLOUDY SKIES
TO AGAIN LEAD TO SOME FOG AROUND EARLY FRIDAY MORNING. THE FOG SHOULD
NOT BE AS PERVASIVE AS IT IS THIS MORNING.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
810 AM EDT THU AUG 14 2014
.UPDATE...
ISSUED AT 745 AM EDT THU AUG 14 2014
THE FRONT IS SETTLING INTO THE AREA WITH SOME SPRINKLES ALREADY NOTED
ON RADAR NORTH OF INTERSTATE 64. HAVE ADDED THIS TO THE POP AND WX
GRIDS. THE FOG IS FOUND MAINLY IN THE VALLEYS THROUGH EAST KENTUCKY
WITH SOME LOCALLY DENSE PATCHES. DID ALSO FINE TUNE THE T/TD GRIDS
PER THE LATEST OBS AND TRENDS. THESE HAVE BEEN SENT TO THE NDFD AND
WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 315 AM EDT THU AUG 14 2014
06Z SFC ANALYSIS SHOWS WEAK HIGH PRESSURE THROUGH THE TENNESSEE
VALLEY WITH A MOSTLY DRY COLD FRONT TO OUR NORTH DROPPING SOUTH
THROUGH THE OHIO VALLEY. THIS HAS LEFT MOST OF EAST KENTUCKY UNDER
CLEAR SKIES WITH A DRY AIR MASS IN PLACE. COMBINED WITH LIGHT
WINDS...THE RADIATIVE COOLING IS HELPING TO DROP TEMPERATURES INTO
THE 50S THROUGH THE AREA. IN THE VALLEYS THESE TEMPS ARE GETTING
CLOSE TO THE DEWPOINTS RESULTING IN THE FORMATION OF FOG ALONG WITH
THE POTENTIAL FOR LOCALLY DENSE PATCHES. HAVE ALLOWED FOR THIS IN THE
GRIDS THROUGH 13Z. ASSOCIATED WITH THE DESCENDING FRONT TO THE
NORTH...A PATCH OF MID LEVEL CLOUDS ARE SETTING INTO NORTHERN
KENTUCKY AND THIS SHOULD LIMIT THE COOLING AND FOG FORMATION IN THOSE
PARTS THROUGH DAWN. THE AREAS OF DENSE FOG WILL BE HIGHLIGHTED IN THE
HWO FOR EARLY THIS MORNING.
THE MODELS ARE IN PRETTY GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM
PORTION OF THE FORECAST. THEY ALL DEPICT THE RESURGENCE OF THE
UNSEASONABLY DEEP ONTARIO UPPER LOW THROUGH THE DAY WITH ITS
SOUTHWARD PUSH OF ENERGY AND HEIGHT FALLS. THE BEST ENERGY WITH THIS
WILL STAY JUST NORTHEAST OF JKL THROUGH FRIDAY MORNING BEFORE THE LOW
GYRATES BACK FURTHER NORTH DURING THE DAY FRIDAY ALLOWING FOR RISING
HEIGHTS AND A DEPARTING ENERGY STREAM. WITH A SLIGHTLY SLOWER
MOVEMENT TO THE UPPER LOW...THE NAM KEEPS THE LOWER HEIGHTS IN THE
SOUTHERN OHIO VALLEY A BIT LONGER INTO THE DAY FRIDAY. HAVE FAVORED A
GENERAL MODEL BLEND GIVEN THE SIMILARITIES...THOUGH THE HIGHER
RESOLUTION HRRR AND NAM12 WERE GIVEN MORE EMPHASIS FOR THE FIRST
PART OF THE FORECAST.
SENSIBLE WEATHER WILL FEATURE ANOTHER PLEASANTLY COOL AND MOSTLY DRY
DAY UNDER PARTLY CLOUDY TO MOSTLY SUNNY SKIES. THE COLD FRONT WILL
SETTLE INTO NORTHERN PARTS OF THE CWA AND MAKE FOR A THREAT OF
SPRINKLES OR A STRAY SHOWER TODAY. THE MODEL FORECAST SOUNDINGS ARE
UNFAVORABLE FOR THUNDER WITH A MID LEVEL CAP AND LOW CAPE VALUES SO
HAVE KEPT OUT THUNDER FOR THE GRIDS. CANNOT RULE OUT A STRAY SHOWER
INTO THE NIGHT TONIGHT...BUT GIVEN THE LOSS OF DIURNAL HEATING WILL
KEEP IT DRY. AGAIN PATCHY FOG...LOCALLY DENSE...CAN BE ANTICIPATED IN
THE VALLEYS FOR FRIDAY MORNING...BUT PROBABLY NOT AS EXTENSIVE AS
THIS MORNING/S WILL LIKELY END UP. THE FRONT REMAINS AROUND INTO THE
DAY FRIDAY...BUT RISING HEIGHTS WILL KEEP THE RISK OF SPRINKLES OR
SHOWERS TO A MINIMUM...WHILE ANOTHER RELATIVELY COOL SUMMER DAY IS
HAD BY ALL.
USED THE CONSSHORT AS A STARTING POINT FOR THE T/TD/WIND GRIDS
THROUGH THE FIRST 24 HOURS AND THE SUPERBLEND THEREAFTER. DID MAKE
SOME ADJUSTMENTS TONIGHT FOR RIDGE AND VALLEY TEMPERATURE
DIFFERENCES. WITH THE POPS...ENDED UP A NOTCH HIGHER THAN MOS TODAY
AND TONIGHT FOR THE NORTHERN PARTS OF THE AREA...OWING TO THE
FRONT...WAS IN LINE WITH THE GUIDANCE ON FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 300 AM EDT THU AUG 14 2014
THE MODELS WERE STILL IN DECENT AGREEMENT IN THE EXTENDED. THE
OVERALL MID AND UPPER LEVEL PATTERNS ARE PROGGED TO FEATURE A RIDGE
OF HIGH PRESSURE WEAKENING AND RETREATING SOUTHEASTWARD OUT OF THE
OHIO AND TENNESSEE VALLEY REGIONS FRIDAY NIGHT AND SATURDAY. THIS
WILL ALLOW THE PERIOD TO START OUT DRY WITH INCREASING CLOUD COVER
AND LIGHT WINDS ON TAP FOR EASTERN KENTUCKY. THE CLOUD COVER WILL BE
IN RESPONSE TO AN AREA OF LOW PRESSURE AND ITS ASSOCIATED FRONTAL
BOUNDARY TAKING SHAPE OVER THE EAST CENTRAL PLAINS AND MOVING
EASTWARD TOWARD THE AREA SUNDAY AND SUNDAY NIGHT. THE INITIAL AREA
OF LOW PRESSURE LOOKS TO MOVE ACROSS THE AREA SUNDAY NIGHT. A
FRONTAL BOUNDARY EXTENDING FROM THIS LOW WILL STALL OUT ALONG THE
TENNESSEE VALLEY REGION EASTWARD TO THE EAST COAST OF THE CONUS. THE
PRESENCE OF THIS BOUNDARY WOULD KEEP A CHANCE OF SHOWERS AND STORMS
IN THE FORECAST FROM EARLY SUNDAY THROUGH THE END OF THE UPCOMING
WORK WEEK. WAVES OF LOW PRESSURE MOVING ALONG THE FRONT WOULD
PROVIDE THE LIFT NEEDED TO SPAWN SHOWERS AND STORMS AS MOISTURE FORM
THE GULF OF MEXICO RIDES UP AND OVER THE FRONT. THE ISSUE AT HAND
WILL BE THE TIMING OF THESE WAVES OF LOW PRESSURE AND HOW MUCH
MOISTURE THEY WILL HAVE TO TAP INTO. BASED ON THIS BIT OF
UNCERTAINTY...DECIDED TO KEEP PRECIPITATION CHANCES BETWEEN 20 AND
40 PERCENT ACROSS THE BOARD...FAVORING THE DAYTIME HOURS FOR PEAK
ACTIVITY WITH LULLS IN THE ACTION DURING THE NIGHTTIME PERIODS.
TEMPERATURES THROUGHOUT THE PERIOD SHOULD BE ABLE TO RECOVER TO
NORMAL VALUES FOR THIS TIME OF YEAR AS THE GULF OF MEXICO OPENS UP
AND WARM MOIST AIR INVADES THE REGION FROM THE SOUTH. HIGHS IN
GENERAL ARE EXPECTED TO BE IN THE MID 80S THROUGHOUT THE PERIOD WITH
OVERNIGHT LOWS IN THE UPPER 60S THE FIRST SEVERAL NIGHTS...TO AROUND
70 BY THE END OF THE WEEK. THE ONE EXCEPTION MIGHT BE FRIDAY NIGHT
BEFORE THE WINDS SHIFT TO THE SOUTH AND THE WARMER AIR FROM THE GULF
MAKES IT WAY INTO THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 810 AM EDT THU AUG 14 2014
THE IFR AND VLIFR FOG WILL BURN OFF BETWEEN 12 AND 13Z TODAY...
GIVING WAY QUICKLY TO VFR CONDITIONS AND LIGHT NORTHWEST WINDS THAT
WILL LAST THROUGH EVENING. EXPECT CALM WINDS AND PARTLY CLOUDY SKIES
TO AGAIN LEAD TO SOME FOG AROUND EARLY FRIDAY MORNING. THE FOG SHOULD
NOT BE AS PERVASIVE AS IT IS THIS MORNING.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS PADUCAH KY
632 AM CDT Thu Aug 14 2014
.UPDATE...
Issued at 630 am CDT THU AUG 14 2014
Updated for aviation forecast discussion.
&&
.SHORT TERM...(Today through Saturday)
Issued at 229 AM CDT THU AUG 14 2014
High pressure was centered over the region during the overnight
hours, with a frontal boundary draped across parts of IA, IL, IN and
into OH. Models have been advertising this back door cold front for
several days now. It will continue to sag southwest toward the area
today. A band of mid clouds is seen on satellite and METAR
observations/radar indicate that some spotty showers are resulting
from these clouds. The frontal boundary should reach parts of
southern IL and southwest IN by afternoon or early evening.
Models differ on whether precipitation develops into our CWA
however. The 00Z NAM and latest RUC keep the QPF just north of us,
while the GFS indicate a very small sliver of our northernmost
counties have a chance of seeing a few showers. Some of the hi res
models (ARW/NMM) show a band of spotty showers dropping into parts
of southern IL, southwest IN and parts of KY during the late
afternoon hours. Might opt to throw in some light showers or
sprinkles up in the far north since there may be just enough low
level moisture to bring a few drops to the ground. Will wait and see
what surrounding offices want to do.
Temperatures today should be in the lower to mid 80s, similar to
what occurred yesterday. However, it might be a bit warmer in parts
of SEMO today since winds will become more southerly there.
Whatever precipitation does occur later today should be short lived
as the front disintegrates and high pressure tries to build in behind
it tonight. On Friday, moisture begins to increase which will mean
an increase in cloudiness. Meanwhile, mid/upper heights will begin
rising by late in the week and into weekend, which will mean a bump
in temperatures. Sfc winds will also eventually shift around to the
south as well. We should see upper 80s area wide on Friday and
Saturday.
Next item of business is watching how a mid level short wave moves
across the top of a prominent ridge across the mid CONUS. It is
slated to drop southeast toward the area Friday night into Saturday.
We believe Friday night should be mainly dry but chances for rain
will have to be maintained at least in our northwestern sections for
Saturday. However, the better chances look to arrive Saturday night.
.LONG TERM...(Sunday through Wednesday)
Issued at 229 AM CDT THU AUG 14 2014
A blend of the 00z/12z GFS/GEFS and 12z ECENS was used for this
forecast. This resulted in little change to the inherited PoPs and
resultant temperatures. Temperatures will be geared toward MOS and
CONUS raw model output.
Slow moving upper trof is forecast to approach the CWFA Saturday
night and slowly progress ESE across the region through Sunday
night. Will carry good chance PoPs for convection as a result given
the respectable moisture coupled with mid trop forcing that will
accompany the upper system.
The system will head on to the east Monday. Will linger chance PoPs
over the east, and taper them off west. We may see a lull Monday
night as weak s/wv ridging moves overhead. Inherited 20% values and
see no reason to drop them yet, until a more clear signal is
established.
As some deamplification of the pattern occurs, the WNW flow pattern
across the area will weaken. We will be in broad SSW surface slow as
broad low pressure develops over the plains. Little to key in on
feature wise. The models continue to develop QPF over the region in
what should be a weak but unsettled mid trop flow pattern. Therefore
will carry low chance PoPs during the day Tue/Wed, and taper them
off to slight chances at night.
&&
.AVIATION...
Issued at 630 AM CDT WED AUG 13 2014
A few sites have been dealing with some morning fog, but it should
burn off within the next few hours. With high pressure overhead,
winds should be light and variable today. Expecting some cu
development today with the most coverage in the KEVV/KOWB areas
with an incoming weak frontal boundary from the northeast. Could
see some fog development on Friday morning as well.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PADUCAH KY
229 AM CDT Thu Aug 14 2014
.SHORT TERM...(Today through Saturday)
Issued at 229 AM CDT THU AUG 14 2014
High pressure was centered over the region during the overnight
hours, with a frontal boundary draped across parts of IA, IL, IN and
into OH. Models have been advertising this back door cold front for
several days now. It will continue to sag southwest toward the area
today. A band of mid clouds is seen on satellite and METAR
observations/radar indicate that some spotty showers are resulting
from these clouds. The frontal boundary should reach parts of
southern IL and southwest IN by afternoon or early evening.
Models differ on whether precipitation develops into our CWA
however. The 00Z NAM and latest RUC keep the QPF just north of us,
while the GFS indicate a very small sliver of our northernmost
counties have a chance of seeing a few showers. Some of the hi res
models (ARW/NMM) show a band of spotty showers dropping into parts
of southern IL, southwest IN and parts of KY during the late
afternoon hours. Might opt to throw in some light showers or
sprinkles up in the far north since there may be just enough low
level moisture to bring a few drops to the ground. Will wait and see
what surrounding offices want to do.
Temperatures today should be in the lower to mid 80s, similar to
what occurred yesterday. However, it might be a bit warmer in parts
of SEMO today since winds will become more southerly there.
Whatever precipitation does occur later today should be short lived
as the front disintegrates and high pressure tries to build in behind
it tonight. On Friday, moisture begins to increase which will mean
an increase in cloudiness. Meanwhile, mid/upper heights will begin
rising by late in the week and into weekend, which will mean a bump
in temperatures. Sfc winds will also eventually shift around to the
south as well. We should see upper 80s area wide on Friday and
Saturday.
Next item of business is watching how a mid level short wave moves
across the top of a prominent ridge across the mid CONUS. It is
slated to drop southeast toward the area Friday night into Saturday.
We believe Friday night should be mainly dry but chances for rain
will have to be maintained at least in our northwestern sections for
Saturday. However, the better chances look to arrive Saturday night.
.LONG TERM...(Sunday through Wednesday)
Issued at 229 AM CDT THU AUG 14 2014
A blend of the 00z/12z GFS/GEFS and 12z ECENS was used for this
forecast. This resulted in little change to the inherited PoPs and
resultant temperatures. Temperatures will be geared toward MOS and
CONUS raw model output.
Slow moving upper trof is forecast to approach the CWFA Saturday
night and slowly progress ESE across the region through Sunday
night. Will carry good chance PoPs for convection as a result given
the respectable moisture coupled with mid trop forcing that will
accompany the upper system.
The system will head on to the east Monday. Will linger chance PoPs
over the east, and taper them off west. We may see a lull Monday
night as weak s/wv ridging moves overhead. Inherited 20% values and
see no reason to drop them yet, until a more clear signal is
established.
As some deamplification of the pattern occurs, the WNW flow pattern
across the area will weaken. We will be in broad SSW surface slow as
broad low pressure develops over the plains. Little to key in on
feature wise. The models continue to develop QPF over the region in
what should be a weak but unsettled mid trop flow pattern. Therefore
will carry low chance PoPs during the day Tue/Wed, and taper them
off to slight chances at night.
&&
.AVIATION...
Issued at 229 AM CDT WED AUG 13 2014
Persistence strategy suggests vsbys should hold tonight with
minimal fog risk, though it`s something to watch as skies
clear/winds go calm...wouldn`t be a shocker. Otherwise light nlys
and maybe scattered cu bases around 5K again tmrw pm.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
315 AM EDT THU AUG 14 2014
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 315 AM EDT THU AUG 14 2014
06Z SFC ANALYSIS SHOWS WEAK HIGH PRESSURE THROUGH THE TENNESSEE
VALLEY WITH A MOSTLY DRY COLD FRONT TO OUR NORTH DROPPING SOUTH
THROUGH THE OHIO VALLEY. THIS HAS LEFT MOST OF EAST KENTUCKY UNDER
CLEAR SKIES WITH A DRY AIR MASS IN PLACE. COMBINED WITH LIGHT
WINDS...THE RADIATIVE COOLING IS HELPING TO DROP TEMPERATURES INTO
THE 50S THROUGH THE AREA. IN THE VALLEYS THESE TEMPS ARE GETTING
CLOSE TO THE DEWPOINTS RESULTING IN THE FORMATION OF FOG ALONG WITH
THE POTENTIAL FOR LOCALLY DENSE PATCHES. HAVE ALLOWED FOR THIS IN THE
GRIDS THROUGH 13Z. ASSOCIATED WITH THE DESCENDING FRONT TO THE
NORTH...A PATCH OF MID LEVEL CLOUDS ARE SETTING INTO NORTHERN
KENTUCKY AND THIS SHOULD LIMIT THE COOLING AND FOG FORMATION IN THOSE
PARTS THROUGH DAWN. THE AREAS OF DENSE FOG WILL BE HIGHLIGHTED IN THE
HWO FOR EARLY THIS MORNING.
THE MODELS ARE IN PRETTY GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM
PORTION OF THE FORECAST. THEY ALL DEPICT THE RESURGENCE OF THE
UNSEASONABLY DEEP ONTARIO UPPER LOW THROUGH THE DAY WITH ITS
SOUTHWARD PUSH OF ENERGY AND HEIGHT FALLS. THE BEST ENERGY WITH THIS
WILL STAY JUST NORTHEAST OF JKL THROUGH FRIDAY MORNING BEFORE THE LOW
GYRATES BACK FURTHER NORTH DURING THE DAY FRIDAY ALLOWING FOR RISING
HEIGHTS AND A DEPARTING ENERGY STREAM. WITH A SLIGHTLY SLOWER
MOVEMENT TO THE UPPER LOW...THE NAM KEEPS THE LOWER HEIGHTS IN THE
SOUTHERN OHIO VALLEY A BIT LONGER INTO THE DAY FRIDAY. HAVE FAVORED A
GENERAL MODEL BLEND GIVEN THE SIMILARITIES...THOUGH THE HIGHER
RESOLUTION HRRR AND NAM12 WERE GIVEN MORE EMPHASIS FOR THE FIRST
PART OF THE FORECAST.
SENSIBLE WEATHER WILL FEATURE ANOTHER PLEASANTLY COOL AND MOSTLY DRY
DAY UNDER PARTLY CLOUDY TO MOSTLY SUNNY SKIES. THE COLD FRONT WILL
SETTLE INTO NORTHERN PARTS OF THE CWA AND MAKE FOR A THREAT OF
SPRINKLES OR A STRAY SHOWER TODAY. THE MODEL FORECAST SOUNDINGS ARE
UNFAVORABLE FOR THUNDER WITH A MID LEVEL CAP AND LOW CAPE VALUES SO
HAVE KEPT OUT THUNDER FOR THE GRIDS. CANNOT RULE OUT A STRAY SHOWER
INTO THE NIGHT TONIGHT...BUT GIVEN THE LOSS OF DIURNAL HEATING WILL
KEEP IT DRY. AGAIN PATCHY FOG...LOCALLY DENSE...CAN BE ANTICIPATED IN
THE VALLEYS FOR FRIDAY MORNING...BUT PROBABLY NOT AS EXTENSIVE AS
THIS MORNING/S WILL LIKELY END UP. THE FRONT REMAINS AROUND INTO THE
DAY FRIDAY...BUT RISING HEIGHTS WILL KEEP THE RISK OF SPRINKLES OR
SHOWERS TO A MINIMUM...WHILE ANOTHER RELATIVELY COOL SUMMER DAY IS
HAD BY ALL.
USED THE CONSSHORT AS A STARTING POINT FOR THE T/TD/WIND GRIDS
THROUGH THE FIRST 24 HOURS AND THE SUPERBLEND THEREAFTER. DID MAKE
SOME ADJUSTMENTS TONIGHT FOR RIDGE AND VALLEY TEMPERATURE
DIFFERENCES. WITH THE POPS...ENDED UP A NOTCH HIGHER THAN MOS TODAY
AND TONIGHT FOR THE NORTHERN PARTS OF THE AREA...OWING TO THE
FRONT...WAS IN LINE WITH THE GUIDANCE ON FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 300 AM EDT THU AUG 14 2014
THE MODELS WERE STILL IN DECENT AGREEMENT IN THE EXTENDED. THE
OVERALL MID AND UPPER LEVEL PATTERNS ARE PROGGED TO FEATURE A RIDGE
OF HIGH PRESSURE WEAKENING AND RETREATING SOUTHEASTWARD OUT OF THE
OHIO AND TENNESSEE VALLEY REGIONS FRIDAY NIGHT AND SATURDAY. THIS
WILL ALLOW THE PERIOD TO START OUT DRY WITH INCREASING CLOUD COVER
AND LIGHT WINDS ON TAP FOR EASTERN KENTUCKY. THE CLOUD COVER WILL BE
IN RESPONSE TO AN AREA OF LOW PRESSURE AND ITS ASSOCIATED FRONTAL
BOUNDARY TAKING SHAPE OVER THE EAST CENTRAL PLAINS AND MOVING
EASTWARD TOWARD THE AREA SUNDAY AND SUNDAY NIGHT. THE INITIAL AREA
OF LOW PRESSURE LOOKS TO MOVE ACROSS THE AREA SUNDAY NIGHT. A
FRONTAL BOUNDARY EXTENDING FROM THIS LOW WILL STALL OUT ALONG THE
TENNESSEE VALLEY REGION EASTWARD TO THE EAST COAST OF THE CONUS. THE
PRESENCE OF THIS BOUNDARY WOULD KEEP A CHANCE OF SHOWERS AND STORMS
IN THE FORECAST FROM EARLY SUNDAY THROUGH THE END OF THE UPCOMING
WORK WEEK. WAVES OF LOW PRESSURE MOVING ALONG THE FRONT WOULD
PROVIDE THE LIFT NEEDED TO SPAWN SHOWERS AND STORMS AS MOISTURE FORM
THE GULF OF MEXICO RIDES UP AND OVER THE FRONT. THE ISSUE AT HAND
WILL BE THE TIMING OF THESE WAVES OF LOW PRESSURE AND HOW MUCH
MOISTURE THEY WILL HAVE TO TAP INTO. BASED ON THIS BIT OF
UNCERTAINTY...DECIDED TO KEEP PRECIPITATION CHANCES BETWEEN 20 AND
40 PERCENT ACROSS THE BOARD...FAVORING THE DAYTIME HOURS FOR PEAK
ACTIVITY WITH LULLS IN THE ACTION DURING THE NIGHTTIME PERIODS.
TEMPERATURES THROUGHOUT THE PERIOD SHOULD BE ABLE TO RECOVER TO
NORMAL VALUES FOR THIS TIME OF YEAR AS THE GULF OF MEXICO OPENS UP
AND WARM MOIST AIR INVADES THE REGION FROM THE SOUTH. HIGHS IN
GENERAL ARE EXPECTED TO BE IN THE MID 80S THROUGHOUT THE PERIOD WITH
OVERNIGHT LOWS IN THE UPPER 60S THE FIRST SEVERAL NIGHTS...TO AROUND
70 BY THE END OF THE WEEK. THE ONE EXCEPTION MIGHT BE FRIDAY NIGHT
BEFORE THE WINDS SHIFT TO THE SOUTH AND THE WARMER AIR FROM THE GULF
MAKES IT WAY INTO THE AREA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 155 AM EDT THU AUG 14 2014
MOSTLY CLEAR SKIES AND NEARLY CALM WINDS WILL LIKELY ALLOW FOR SOME
DENSE FOG TO DEVELOP ACROSS EASTERN KENTUCKY LATER TONIGHT...
PARTICULARLY IN THE VALLEYS. FOG ALREADY EXISTS IN THESE SPOTS AND
WILL EXPAND INTO MOST OF THE VALLEYS AND EVEN UP SOME RIDGES DURING
THE 08 TO 12Z TIME FRAME. HAVE GONE LIFR AT MOST LOCATIONS...AND
INCLUDED SOME IFR AT JKL ...OR THIS. THE FOG WILL BURN OFF BETWEEN
12 AND 13Z THURSDAY...GIVING WAY QUICKLY TO VFR CONDITIONS AND LIGHT
NORTHWEST WINDS THAT WILL LAST THROUGH THURSDAY EVENING.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS CARIBOU ME
638 AM EDT THU AUG 14 2014
.SYNOPSIS...
LOW PRESSURE WILL LIFT ACROSS THE REGION TODAY BRINGING SOME HEAVY
RAINFALL WITH IT TO THE REGION. THE LOW IS EXPECTED TO WEAKEN AS
IT LIFTS NORTH OF THE MAINE BORDER TONIGHT WHILE THE UPPER LOW
REMAINS PARKED OVER QUEBEC INTO FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
630 AM UPDATE...LATEST SURFACE ANALYSIS SHOWED LOW PRES LIFTING UP
ACROSS THE MID COAST W/THE OCCLUDED FRONT MOVING N. LATEST RADAR
IMAGERY SHOWED THE HEAVIES RAIN HAS NOW SHIFTED N AND E THE BACK
EDGE OF THE RAIN SHIELD NOW ACROSS PISCATAQUIS AND PENOBSCOT
COUNTIES. THE LATEST RUN OF THE HRRR 3KM MODEL HAD THIS HANDLED
WELL AND THEREFORE DECIDED TO MOVE THE HIGHEST RAINFALL CHANCES UP
ACROSS THE NORTHERN AND EASTERN SECTIONS. ISOLATED TSTMS POSSIBLE
INTO THE AFTERNOON W/SOME GUSTY WINDS AS EVIDENT OF THE LATEST
NAM/GFS SOUNDINGS.
PREVIOUS DISCUSSION...
HEAVY RAIN/FLASH FLOODING AND TSTMS THE BIG CHALLENGE FOR THIS
TERM.
06Z MESO ANALYSIS SHOWED AN OCCLUDED FRONT LIFTING N W/LOW PRES
DEVELOPING ON THE FRONT JUST E OF PWM. RADAR IMAGERY SHOWED A
LARGE SWATH OF RAIN LIFTING NORTH ACROSS THE CWA W/SOME VERY HEAVY
RAINFALL ACROSS THE CENTRAL HIGHLANDS AND WESTERN MOUNTAINS.
ALREADY HAD 2+ INCHES IN THE LAST 8 HRS ACROSS SOUTHERN
PISCATAQUIS COUNTY W/A STRONG INFLOW FROM SSE AND A THETA E RIDGE
RESIDING ACROSS THE REGION AIDING IN THE HEAVY RAINFALL. HEAVY
RAIN AXIS WILL SHIFT N TODAY ACROSS N AND NW AREAS W/GOOD LLVL
CONVERGENCE IN PLACE AND A STRONG LLVL JET OF 40+ KTS OVERHEAD.
A FLASH FLOOD WATCH REMAINS IN PLACE FOR NORTHERN SOMERSET AND
ALL OF PISCATAQUIS COUNTY THROUGH 12 PM AS SOME FLASH FLOODING IS
POSSIBLE GIVEN THE SSE WIND AND EMBEDDED TSTMS. THE NAM AND GFS
SOUNDINGS SUPPORT SOME ELEVATED CONVECTION INTO THE AFTERNOON
ACROSS MUCH OF THE CWA W/THE EXCEPTION OF THE COAST. 0-6KM SHEAR
OF 35+M KTS AND SOME DIRECTIONAL SHEAR COULD AID IN SOME STRONG
WIND GUSTS MIXING DOWN IN TSTMS ALONG W/THE RAIN. DECIDED TO ADD
THE GUSY WINDS IN THE FORECAST TODAY BASED ON THIS ASSESSMENT.
STEADY RAIN WILL BE SITUTAED ACROSS NORTHERN AREAS LATE THIS
AFTERNOON WHILE THE CENTRAL AND DOWNEAST AREAS WILL SEE A
TRANSITION TO SHOWERS AS A WSW WIND TAKES OVER AND FORCING
WEAKENS. DRYING ABOVE 700MBS IS NOTED BY BOTH THE NAM AND GFS
SOUNDINGS AS WELL. AFTERNOON TEMPERATURES WILL NOT RECOVER MUCH
HOWEVER, AS RAIN AND CLOUDS WILL KEEP AFTERNOON READINGS MUCH
BELOW NORMAL. WE ARE TALKING MID 60S FOR THE NORTHERN 1/2 WHILE
UPPER 60S TO AROUND 70 WILL BE THE GOING RATE FOR THE CENTRAL AND
DOWNEAST AREAS.
RAIN IS EXPECTED TO WIND DOWN THIS EVENING ACROSS THE NORTH AS THE
FRONT LIFTS N OF THE MAINE BORDER AS THE SFC LOW WEAKENS. DECIDED
TO DROP BACK THE POPS TO CHANCE(40%) ACROSS THE NORTHERN 3RD BY
MIDNIGHT WHILE CENTRAL AND DOWNEAST AREAS WILL BEGIN TO DRY OUT.
WINDS WILL DROP OFF AS WELL W/SOME PARTIAL CLEARING TOWARD EARLY
MORNING ESPECIALLY FOR THE CENTRAL AND DOWNEAST AREAS. THIS WILL
ALLOW FOR FOG FORMATION AND DECIDED TO CARRY FOG FOR OVERNIGHT
INTO EARLY FRIDAY MORNING.
&&
.SHORT TERM /FRIDAY/...
A COLD CORE LOW WILL REMAIN OVER SOUTHERN QUEBEC THROUGH THE NEAR
TERM PERIOD OF THE FORECAST. THE LOW WILL SLOWLY FILL AND DRIFT TO
THE NORTHEAST INTO NORTH CENTRAL QUEBEC BY THE END OF THE PERIOD.
A NEW FRONTAL SYSTEM WILL PUSH INTO SRN MAINE TOWARDS THE END OF
THE PERIOD. SCATTERED SHOWERS WILL PERSIST ACROSS MAINLY THE NORTH
AND CENTRAL PORTIONS OF THE CWA THROUGH THE PERIOD.
LOADED A BLEND OF NAM/GFS/GEM/ECMWF THROUGH THE PERIOD FOR ALL
ELEMENTS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
AT THE START OF THE PERIOD A COLD CORE LOW OVER NORTH CENTRAL
QUEBEC WILL CONTINUE TO FILL AS IT DRIFT EAST. A TROUGH OF LOWER
WILL EXTEND ALONG THE SW COAST WEST ACROSS THE ERN GREAT LAKES
REGION. THERE WILL BE LOWS ALONG THE TROUGH. THE ECMWF CENTERS A
LOW ALONG THE SW COAST...WITH A SECOND LOW OVER LAKE HURON. THE
GEM AND NAM HAVE A LOW OVER VERMONT. THE GFS DOES NOT INDICATE A
SPECIFIC LOW. THE TROUGH WILL SLOWLY PUSH SOUTH INTO THE CENTRAL
GULF OF MAINE BY SUN EVNG. THE GFS/ECMWF/GEM ALL SHOW THE FILLING
COLD CORE LOW MOVING SE ACROSS MAINE/NEW BRUNSWICK DURING THE DAY
MONDAY...THE ENERGY BEING COLLECTED BY A NEW DYNAMIC LOW MOVING
INTO THE GULF OF ST LAWRENCE...WITH HIGHER PRESSURE RIDGING INTO
THE CWA BEHIND THE DEPARTING LOW.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
NEAR TERM: MVFR ACROSS THE NORTHERN TERMINALS THIS MORNING
DROPPING TO IFR W/HEAVY RAIN. KBGR AND KBHB WILL SEE IFR W/PERIODS
OF MVFR THIS MORNING. CONDITION FOR THESE TERMINALS SHOULD RECOVER
TO MVFR BY THIS AFTERNOON W/VFR BY EARLY TONIGHT. ACROSS THE
NORTHERN TERMINALS FROM KHUL N THROUGH KFVE, IFR GOING TO MVFR
LOOKS TO BE IN ORDER. SOME LLWS IS POSSIBLE TODAY ESPECIALLY
IN ANY TSTMS.
SHORT TERM: MAINLY VFR CONDITIONS ACROSS NRN AND CNTRL ME THROUGH THE PERIOD.
OCNL PERIODS WERE CIGS WILL FALL MVFR IN SHWRS. VFR CONDITIONS FOR
BGR AND BHB THROUGH EARLY SUN MRNG. VSBY AND CIGS WILL BEGIN
FALLING LATE SAT TO EARLY SUN MRNG FOR DOWNEAST AND INTERIOR
DOWNEAST AS THE NEXT FRONTAL SYSTEM APPROACHES FROM THE SW. MVFR
CONDITIONS ACROSS NRN AND CNTRL ME SUNDAY BCMG VFR EARLY MONDAY.
OCNL PERIODS WERE CIGS WILL FALL IFR IN SHWRS. IFR TO LMVFR
CONDITIONS FOR BGR AND BHB THROUGH SUNDAY AND MONDAY...VSBY AND
CIGS WILL BEGIN IMPROVING EARLY TUES MRNG FOR DOWNEAST AND
INTERIOR DOWNEAST AS THE HIGH BUILDS IN FROM THE NW.
&&
.MARINE...
NEAR TERM: SCA CONDITIONS ARE OCCURRING ATTM PER THE LATEST BUOYS.
DECIDED TO USE THE GFSSWAN GUIDANCE FOR WINDS/SEAS AS IT IS
HANDLING THINGS QUITE WELL PER THE LATEST CONDITIONS. GUSTS ARE
25+ KTS. INCREASED THE SUSTAINED AND THE GUSTS BY 5 KTS BASED ON
THESE TRENDS. DECIDED TO STAY W/THE SCA THROUGH THE AFTERNOON.
WINDS LOOK LIKE THEY WILL COME DOWN AS THE LLVL JET MOVES NORTH
OF THE WATERS. SEAS WILL MOST LIKELY STAY UP NEAR 6 FT A WHILE
LONGER AS HEIGHTS ATTM ARE RUNNING 8-10 FT. THE DAYCREW MAY BE
ABLE TO TRANSITION THE HEADLINE FOR MAINLY SEAS LATER TODAY.
CONDITIONS DO LOOK LIKE THEY WILL COME DOWN BELOW SCA LEVELS LATER
TONIGHT AS WINDS GO OFFSHORE.
SHORT TERM: WINDS AND SEAS WILL BE BELOW SCA THROUGH THE PERIOD.
&&
.HYDROLOGY...
AS STATED ABOVE, THE FLASH FLOOD WATCH IS IN PLACE W/POTENTIAL FOR
SOME FLASH FLOODING. THE AREAS W/THE GREATEST THREAT WILL BE
PISCATAQUIS COUNTY AS HEAVY RAIN HAS BEEN TRAINING ACROSS THIS
REGION W/EMBEDDED TSTMS. FLASH FLOOD GUIDANCE IS NEAR 3 INCHES IN 3
HOURS AND SOME AREAS IN PISCATAQUIS COUNTY WERE CLOSE TO THIS
GUIDANCE EARLY THIS MORNING. HEAVY RAIN AXIS WILL SHIFT NORTH OF
THIS REGION LATER THIS MORNING INTO THE AFTERNOON. AREAS FURTHER
TO THE N AND E, SHOULD BE ABLE TO HANDLE THE HEAVY RAINFALL.
STREAMS AND RIVERS WERE LOW BUT ARE AND WILL CONTINUE TO SEE RISES
TODAY, BUT REMAIN WELL WITHIN THEIR BANKS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...FLASH FLOOD WATCH UNTIL NOON EDT TODAY FOR MEZ003-004-010-031.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR
ANZ050>052.
&&
$$
NEAR TERM...HEWITT
SHORT TERM...NORTON
LONG TERM...NORTON
AVIATION...HEWITT/NORTON
MARINE...HEWITT/NORTON
HYDROLOGY...HEWITT
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
130 PM EDT THU AUG 14 2014
.SYNOPSIS...
AFTER A FEW SHOWERS OR SPRINKLES TODAY...DRY AND COOL CONDITIONS
CAN BE EXPECTED INTO SATURDAY. THE NEXT WEATHER SYSTEM WILL AFFECT
US SUNDAY AS AN UPPER DISTURBANCE PASSES.
&&
.NEAR TERM /THROUGH TONIGHT/...
LOWER MID LEVEL HEIGHTS CONTINUE TO ENCOMPASS THE AREA WHILE
TRIGGER TEMPERATURES HAVE BEEN ATTAINED OVER MUCH OF THE REGION
ALLOWING CU TO FORM. REGIONAL RADAR MOSAIC AS OF 15Z REMAINS QUIET
AND BASED ON LATEST HRRR SCALED ISOLD SHOWER MENTION BACK TO THE
FAR NORTHERN SECTIONS /N OF I-80/. TEMPS ON TRACK WITH READINGS
NEARLY 10 DEGREES BELOW NORMAL.
HIGH PRESSURE BUILDS INTO THE AREA TONIGHT ALLOWING FOR A
COOL NIGHT. THE ONLY FLY IN THE OINTMENT WOULD BE A POCKET OF LLVL
RH ILLUSTRATED BY NAM MODEL THAT DROPS S FORM LAKE ERIE INTO THE
MTNS DURING THE OVERNIGHT HOURS. FOR NOW...INCREASED SKY COVER FOR
PA COUNTIES...BUT THIS MAY NEED TO BE ADJUSTED AFTER FULL SUITE
OF 12Z MODELS ARRIVE.
RECORD LOWS FOR PIT/MGW/ZZV APPEAR SAFE TONIGHT WITH READINGS
IN THE UPPER 30S AND LOWER 40S.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
DRY AND A SLOW WARMING TREND FRIDAY AND SATURDAY AS HIGH PRESSURE
SLIDES EAST ACROSS THE REGION. NEXT UPPER LEVEL TROUGH APPROACHES
LATER SATURDAY NIGHT INTO SUNDAY WITH INCREASING LOW LEVEL
MOISTURE AND CHANCE POPS FOR SHOWERS AND THUNDERSTORMS.
TEMPERATURES WILL WARM TO NEAR SEASONAL AVERAGE BY SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
GENL ZONAL FLOW IS PROGGED TO SET UP ACRS THE RGN THRU THE PD. MDLS
CONT TRENDING TWD SVRL CROSSING SHRTWVS EMBEDDED IN THE FLOW...AND
AS A RESULT INCLUDED CHC POPS FOR SHWRS/TSTMS THRU MUCH OF THE PD.
DETAILS WL DEPEND ON SPECIFIC SFC BNDRY PLACEMENT AND TIMING OF
SHRTWVS. TEMPS SHOULD AVG NR SEASONAL LVLS.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
MAINLY JUST SCATTERED CLOUDS ACROSS REGION. NORTHWEST WINDS WILL BE
GUSTY AT TIMES TILL SUNSET. OTHERWISE CLEAR INTO FRIDAY.
OUTLOOK...RESTRICTIONS ARE POSSIBLE SUNDAY IN SHOWERS AND
THUNDERSTORMS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1127 AM EDT THU AUG 14 2014
.SYNOPSIS...
AFTER A FEW SHOWERS OR SPRINKLES TODAY...DRY AND COOL CONDITIONS
CAN BE EXPECTED INTO SATURDAY. THE NEXT WEATHER SYSTEM WILL AFFECT
US SUNDAY AS AN UPPER DISTURBANCE PASSES.
&&
.NEAR TERM /THROUGH TONIGHT/...
LOWER MID LEVEL HEIGHTS CONTINUE TO ENCOMPASS THE AREA WHILE
TRIGGER TEMPERATURES HAVE BEEN ATTAINED OVER MUCH OF THE REGION
ALLOWING CU TO FORM. REGIONAL RADAR MOSAIC AS OF 15Z REMAINS QUIET
AND BASED ON LATEST HRRR SCALED ISOLD SHOWER MENTION BACK TO THE
FAR NORTHERN SECTIONS /N OF I-80/. TEMPS ON TRACK WITH READINGS
NEARLY 10 DEGREES BELOW NORMAL.
HIGH PRESSURE BUILDS INTO THE AREA TONIGHT ALLOWING FOR A
COOL NIGHT. THE ONLY FLY IN THE OINTMENT WOULD BE A POCKET OF LLVL
RH ILLUSTRATED BY NAM MODEL THAT DROPS S FORM LAKE ERIE INTO THE
MTNS DURING THE OVERNIGHT HOURS. FOR NOW...INCREASED SKY COVER FOR
PA COUNTIES...BUT THIS MAY NEED TO BE ADJUSTED AFTER FULL SUITE
OF 12Z MODELS ARRIVE.
RECORD LOWS FOR PIT/MGW/ZZV APPEAR SAFE TONIGHT WITH READINGS
IN THE UPPER 30S AND LOWER 40S.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
DRY AND A SLOW WARMING TREND FRIDAY AND SATURDAY AS HIGH PRESSURE
SLIDES EAST ACROSS THE REGION. NEXT UPPER LEVEL TROUGH APPROACHES
LATER SATURDAY NIGHT INTO SUNDAY WITH INCREASING LOW LEVEL
MOISTURE AND CHANCE POPS FOR SHOWERS AND THUNDERSTORMS.
TEMPERATURES WILL WARM TO NEAR SEASONAL AVERAGE BY SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
GENL ZONAL FLOW IS PROGGED TO SET UP ACRS THE RGN THRU THE PD. MDLS
CONT TRENDING TWD SVRL CROSSING SHRTWVS EMBEDDED IN THE FLOW...AND
AS A RESULT INCLUDED CHC POPS FOR SHWRS/TSTMS THRU MUCH OF THE PD.
DETAILS WL DEPEND ON SPECIFIC SFC BNDRY PLACEMENT AND TIMING OF
SHRTWVS. TEMPS SHOULD AVG NR SEASONAL LVLS.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
VFR. CU WILL RAPIDLY DEVELOP THIS MORNING WITH BKN CIGS AT FKL
AND DUJ...OTHERWISE SCT CLOUD COVER. ANY CU WILL DISSIPATE WITH
LOSS OF HEATING OWING TO A SKC CONDITIONS TNGT.
OUTLOOK.../FRIDAY THROUGH MONDAY/...
RESTRICTIONS ARE POSSIBLE SUNDAY IN SHOWERS AND THUNDERSTORMS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
NEAR TERM...98
AVIATION...98
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
742 PM EDT FRI AUG 15 2014
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 351 PM EDT FRI AUG 15 2014
WV IMAGERY AND RUC ANALYSIS INDICATED NW MID/UPPER LEVEL FLOW
THROUGH THE WRN GREAT LAKES BETWEEN A RIDGE FROM THE NRN PLAINS INTO
CNTRL ALBERTA AND A TROUGH OVER QUEBEC. AN UPSTREAM SHORTWAVE TROUGH
AND ASSOCIATED COLD FRONT WAS DIVING SE THROUGH NW ONTARIO. AT THE
SFC...LIGHT SW WINDS PREVAILED ACROSS UPPER MI AS HIGH PRES SINKS
INTO THE SRN LAKES.
TONIGHT INTO SAT...EXPECT SHRA/TSRA TO DEVELOP MAINLY AFT 06Z OVER
NORTHERN LAKE SUPERIOR THAT WILL SPREAD QUICKLY SE AS MODELS WERE IN
GOOD AGREEMENT IN BRINGING THE SHORTWAVE TROUGH WITH MODERATE 700-300
MB QVECTOR CONV...STRONG UPPER LEVEL DIV WITH THE LEFT EXIT OF A 90
KNOT 250-300 MB JET...AND AN ASSOCIATED COLD FRONT THROUGH THE NRN
GREAT LAKES. MODELS SHRTWV FORCING SUGGEST THAT THE ERN CWA WILL SEE
THE GREATEST PCPN COVERAGE/QPF WITH LIKELY TO CATEGORICAL POPS. GIVEN
POTENTIAL OF MUCAPE TO NEAR 800 J/KG... MODERATE TO STRONG DYNAMICS
AND EFFECTIVE SHEAR TO 40 KNOTS SOME EVEN MAINLY ELEVATED STORMS
ABOVE THE SHALLOW BNDRY LAYER MAY BE STRONG CAPABLE OF PRODUCING SOME
GUSTY WINDS AND SMALL HAIL. BY SAT AFTERNOON IN THE WAKE OF THE
FRONT...PCPN CHANCES SHOULD DIMINISH ACROSS THE NORTH WITH COOLER
MORE STABLE AIR MOVING IN ON LOW LEVEL NRLY FLOW. SOME DRIZZLE MAY
LINGER IN THE HIGHER TERRAIN N CNTRL IN THE MORNING IN THE WAKE OF
ANY SHOWERS EARLIER IN THE MORNING.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 348 PM EDT FRI AUG 15 2014
MAIN FCST CONCERNS IN THE LONG RANGE WL FOCUS ON TEMPS/PSBL LO CLDS
EARLY NEXT WEEK WITH NNE FLOW ON THE SRN FLANK OF DRY CNDN HI PRES
FCST TO DOMINATE. HOW QUICKLY A CHC OF SHOWERS WL RETURN TO THE FCST
IS THE CHALLENGE FOR THE MIDDLE OF NEXT WEEK.
SAT NGT...UNDER CONFLUENT NW FLOW ALF BTWN UPR RDG IN THE PLAINS AND
DEEP TROF IN QUEBEC...SFC HI PRES OVER FAR NW ONTARIO IS PROGGED TO
DRIFT SLOWLY SEWD TOWARD NRN LK SUP BY 12Z SUN. ANY LINGERING CLDS
EARLY OVER THE SCENTRAL ASSOCIATED WITH DEPARTING COLD FNT WL SHIFT
TO THE S AS THE HI PRES BUILDS TOWARD THE CWA UNDER LARGER SCALE
DNVA/DEEP LYR QVECTOR DVGC AND THE AIRMASS DRIES. IN FACT...
GUIDANCE INDICATES PWAT WL SINK TO ARND 0.5 INCH BY 12Z SUN...ABOUT
50 PCT OF NORMAL. THE MAJOR CONCERN IS THE POTENTIAL FOR SOME LO
CLDS TO DVLP...MAINLY IN THOSE AREAS OVER THE NCNTRL IMPACTED BY
UPSLOPE NNE WIND COMPONENT ON THE SRN FLANK OF THE APRCHG HI PRES.
IN FACT...THE 12Z NAM/REGIONAL CNDN/LOCAL WRF ARW FCST SDNGS SHOW A
SHALLOW...MOIST INFUSION OF COOLER AIR BLO SHARP SUBSIDENCE INVRN
BASED NEAR H9 ASSOCIATED WITH THE LARGER SCALE SUBSIDENCE/DRYING.
THESE FCSTS ARE BACKED UP BY SOME FAIRLY EXTENSIVE LO CLD COVER NOW
PRESENT OVER FAR NW ONTARIO ASSOCIATED WITH SHALLOW MOIST LYR
DEPICTED ON THE 12Z CHURCHILL MANITOBA RAOB. WL THUS INTRODUCE MORE
CLDS INTO THE FCST...MAINLY OVER THE NCENTRAL. THESE CLDS AND
EXPECTED STEADY NNE WIND WL LIMIT THE DIURNAL TEMP FALL A BIT
ESPECIALLY NEAR LK SUP OVER THE E HALF WHERE THE PRES GRADIENT IS
FCST TO BE A BIT TIGHTER. EXPECT THE LOWEST MIN TEMPS IN THE 40S
OVER THE INTERIOR W...CLOSER TO THE RDG AXIS EXTENDING FM THE HI
CENTER S TOWARD THE UPR MIDWEST AND WHERE WINDS WL BE LIGHTER AND
DOWNSLOPE WIND COMPONENT SHOULD LIMIT THE POTENTIAL FOR MORE
EXTENSIVE LO CLD.
SUN THRU MON...AS UPR RDG AXIS BUILDS INTO THE GREAT LKS FM THE W
FOLLOWING A SLOWLY EXITING QUEBEC TROF...SFC HI PRES IS FCST TO
DRIFT SLOWLY E AND INTO WRN QUEBEC BY MON AFTN. AM LO CLDS MAINLY
OVER THE NCENTRAL ON SUN MRNG SHOULD MIX OUT DURING THE AFTN WITH
DAYTIME HEATING AND THE ARRIVAL OF DRIER AIR. OTRW...THE WX OVER UPR
MI SHOULD REMAIN UNEVENTFUL WITH RDG AXIS EXTENDING WWD FM THE HI
CENTER INTO THE UPR LKS AND RELATIVELY DRY AIRMASS LINGERING. BOTH
SUN AND MON SHOULD FEATURE PLEASANT MAX TEMPS IN THE 70S AWAY FM LK
MODERATION AS H85 TEMPS ARE FCST TO TOP OUT BTWN 10-12C AND SUN AND
11-13C ON MON. MIN TEMPS ON SUN NGT WL DIP INTO THE 40S OVER THE
INTERIOR UNDER MOCLR SKIES/LIGHT WINDS DESPITE A SLOW INCRS IN PWAT
AOA 0.75 INCH.
EXTENDED...REMNANT OF CUTOFF UPR LO NOW MOVING EWD THRU THE PAC NW
IS FCST TO DRIFT SLOWLY E AND INTO THE UPR LKS ON TUE-THU NEXT WEEK
AT THE SAME TIME LARGER SCALE UPR RDG WL BE BUILDING OVER THE UPR
LKS DOWNSTREAM OF DEEPENING TROF OVER WRN CANADA/THE NW CONUS. FCST
WL INCLUDE SOME POPS AS THE SHRTWV/DEEPER MSTR INFLUENCE THE AREA...
BUT SLOWLY RISING H5 UNDER THE EXPANDING MEAN RDG SHOULD TEND TO
LIMIT THE SHOWER COVERAGE AND POPS TO THE CHC RANGE. WITH FCST H85
TEMPS NOT FAR FM 13-15C AND SOME CLDS...TEMPS SHOULD BE NOT FAR FM
THE MID/LATE AUG NORM. AS THE SHRTWV/DEEPER MSTR SLOWLY LIFT TO THE
NE AND H85 TEMPS WARM INTO THE 17-20C RANGE BY NEXT FRI UNDER THE
SLOWLY BLDG UPR RDG...EXPECT A RETURN OF ABV NORMAL TEMPS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 741 PM EDT FRI AUG 15 2014
AHEAD OF A DISTURBANCE AND COLD FRONT APPROACHING FROM THE N...VFR
CONDITIONS WILL PREVAIL THROUGH THIS EVENING AT KWID/KCMX/KSAW.
SHRA/TSRA ALONG COLD FRONT WILL PUSH S INTO UPPER MI OVERNIGHT INTO
EARLY SAT MORNING WITH KCMX/KSAW MORE LIKELY TO SEE PCPN THAN KIWD.
THERE IS UNCERTAINTY IN WHETHER TSRA WILL PERSIST ALONG COLD FRONT
LATE TONIGHT...SO ONLY -SHRA WERE INCLUDED IN FCST FOR NOW. BEHIND
FRONT...A PERIOD OF IFR CIGS IS LIKELY AT ALL TERMINALS SAT MORNING
UNDER MOIST UPSLOPE FLOW...ESPECIALLY AT KSAW DUE TO UPSLOPE FLOW
OFF THE COLDER ERN PORTION OF LAKE SUPERIOR. GRADUAL IMPROVEMENT TO
VFR SHOULD OCCUR AT KIWD/KCMX SAT WHILE KSAW MAY ONLY IMPROVE TO
MVFR.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 348 PM EDT FRI AUG 15 2014
EXPECT WINDS UNDER 20 KTS THRU NEXT WED AS A RELATIVELY WEAK PRES
GRADIENT DOMINATES THE UPPER GREAT LAKES ABOVE THE CHILLY WATERS OF
LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KC
AVIATION...ROLFSON
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
449 AM EDT THU AUG 14 2014
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 331 PM EDT WED AUG 13 2014
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW NNW FLOW ALF OVER
THE UPR LKS BETWEEN SHARP UPR TROF CENTERED NEAR JAMES BAY AND AN
UPR RDG OVER THE WRN PLAINS. THERE IS A SHRTWV EMBEDDED IN THIS FLOW
THAT IS DIVING THRU ERN LK SUP...BUT THE MID LVLS ARE SUFFICIENTLY
DRY/STABLE OVER THE UPR LKS PER THE 12Z INL/YPL RAOBS THAT THERE
HAVE BEEN NO SHOWERS. BUT THESE RAOBS ALL SHOW A GOOD DEAL OF LLVL
MSTR. WITH THE ONSET OF DAYTIME HEATING...A GOOD DEAL OF LO CLD
DVLPD...ESPECIALLY OVER THE W AND NCENTRAL WHERE THE SFC-H925 NLY
FLOW UPSLOPES OFF LK SUP. THE STEADY/GUSTY N WIND IS CAUSING HIER
WAVES/DANGEROUS SWIMMING CONDITIONS IN THE LK SUP BEACHES E OF THE
KEWEENAW. CLOSER TO HI PRES OVER FAR NW ONTARIO WHERE THE LLVL
AIRMASS IS MUCH DRIER AS SHOWN ON THE 12Z CHURCHILL MANITOBA
RAOB...THERE ARE FEWER CLDS AND WINDS ARE LGT.
MAIN FCST CONCERNS IN THE SHORT TERM ARE CLD TRENDS THIS AFTN AND
THEN TEMPS TNGT AND THU AS THE DRY HI PRES IN ONTARIO WL DOMINATE.
LATE THIS AFTN/TNGT...UNDER CONFLUENT NW FLOW ALF/DEEP LYR QVECTOR
DVGC...SFC HI PRES OVER FAR NW ONTARIO IS PROGGED TO SINK OVER WRN
LK SUP BY 12Z THU. WITH LOSS OF DAYTIME HEATING AND LLVL DRY ADVCTN
IN THE LLVL NLY FLOW AHEAD OF THE SFC HI PRES...EXPECT ANY LINGERING
CLDS TO DISSIPATE THIS EVNG AND GIVE TO MOCLR SKIES OVERNGT. THE
ARRIVAL OF DRIER AIR FM THE N...WITH PWAT SINKING AS LO AS 0.33 INCH
OR 30-35 PCT OF NORMAL...FAVORS A LARGE DIURNAL DROP OF TEMP...
ESPECIALLY OVER THE W WHERE THE WINDS WL BE LIGHTER CLOSER TO THE
INCOMING SFC RDG AXIS. WL MAINTAIN FCST LO TEMPS IN THE 30S AT THE
COLDER INTERIOR LOCATIONS IN THIS AREA. STEADY N WIND OVER THE E
UNDER THE SHARPER PRES GRADIENT BTWN THE RDG AND LO PRES OVER QUEBEC
WL TEND TO RESTRICT THE DIURNAL TEMP DROP THERE.
THU...SFC HI PRES AXIS IS FCST TO SHIFT FM NCENTRAL UPR MI THRU LK
MI. WITH CORE OF DRY AIR OVHD...EXPECT NOTHING MORE THAN SOME
DIURNAL CU OVER THE INTERIOR. H85 TEMPS ARE FCST TO PEAK BTWN ABOUT
8C OVER THE E TO 12C OVER THE W. MIXING TO H8 ON FCST SDNGS
INDICATES MAX TEMPS WL PEAK NEAR 75 OVER THE INTERIOR W AND
SCENTRAL. WITH A STEADY NW WIND OFF LK SUP OVER THE E THAT WL
MAINTAIN HIER WAVES/SWIM RISK...TEMPS WL HAVE A HARD TIME RISING
OVER 70 EXCEPT CLOSER TO LK MI. AFTN MIXING WL CAUSE MIN RH TO
BOTTOM OUT AS LO AS 30-35 PCT OVER MUCH OF THE INTERIOR. DESPITE THE
SOMEWHAT COOLER TEMPS OVER THE E...STRONGER WINDS WL AGGRAVATE FIRE
WX CONDITIONS THERE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 317 AM EDT THU AUG 14 2014
FOR THE TIME BEING...MODELS ARE IN GOOD AGREEMENT THROUGH MUCH OF
THE FORECAST PERIOD. THE CWA WILL BE UNDER NW FLOW ALOFT FRI INTO
SUN BEFORE AN UPPER RIDGE PASSES OVERHEAD LATE SUN INTO MON...THEN
AN UPPER TROUGH MOVES INTO THE AREA THE REGION TUE INTO WED. HAVE
GOOD CONFIDENCE THROUGH THE WEEKEND...BUT MODELS HAVE SHOWN POOR RUN
TO RUN CONTINUITY NEXT WEEK.
MODELS HAVE TRENDED DRIER ON FRI FOR THE CWA AS THEY DEPICT BEST
FORCING BEING W OF THE CWA AS A SHORTWAVE MOVES THROUGH THE NW FLOW.
WILL CONTINUE TO SHOW SLIGHT CHANCE POPS GIVEN MARGINAL INSTABILITY
/MLCAPE VALUES LESS THAN 500 J/KG/ AND UNCERTAINTY IN THE TRACK OF ANY
SHORTWAVES.
A STRONGER SHORTWAVE AND ASSOCIATED SFC COLD FRONT WILL MOVES
ACROSS THE CWA FRI INTO INTO SAT...BRINGING GREATER CHANCES FOR
PRECIP. WILL FAVOR THE NERN HALF OF THE CWA WITH THE GREATEST POPS
AS MODELS INDICATE BEST FORCING WILL EXIST THERE.
A SFC HIGH MOVES INTO THE REGION ALONG AND AHEAD OF THE UPPER
RIDGE...WHICH SHOULD LEAD TO DRY CONDITIONS SUN THROUGH MON...BEFORE
PRECIP CHANCES INCREASE MON NIGHT INTO WED.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 737 PM EDT WED AUG 13 2014
A DRY AIR MASS ASSOCIATED WITH HIGH PRES BUILDING OVER THE UPPER
GREAT LAKES WILL RESULT IN VFR CONDITIONS PREVAILING AT
KIWD/KCMX/KSAW THRU THIS FCST PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 448 AM EDT THU AUG 14 2014
W-NW GUSTS OF 20-25KTS WILL REMAIN POSSIBLE OVER MAINLY THE E HALF
OF LAKE SUPERIOR THROUGH THE EARLY EVENING HOURS. HIGH PRESSURE OVER
W LAKE SUPERIOR WILL WEAKEN SLIGHTLY ACROSS ALL OF LAKE SUPERIOR ON
THURSDAY...BEFORE DIVING TO THE OH RIVER VALLEY THURSDAY NIGHT INTO
FRIDAY. A TROUGH EXTENDING FROM THE DAKOTAS THROUGH HUDSON BAY WILL
SINK ACROSS LAKE SUPERIOR SATURDAY MORNING...AND ACROSS LOWER MI AND
LAKE HURON SATURDAY EVENING. THIS WILL ALLOW A LARGE HIGH OVER N
ONTARIO SATURDAY NIGHT TO PUSH ACROSS LAKE SUPERIOR SUNDAY AFTERNOON
THROUGH MONDAY...AS A TROUGH OF LOW PRESSURE DEVELOPS OVER MANITOBA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...ROLFSON
MARINE...
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
317 AM EDT THU AUG 14 2014
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 331 PM EDT WED AUG 13 2014
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW NNW FLOW ALF OVER
THE UPR LKS BETWEEN SHARP UPR TROF CENTERED NEAR JAMES BAY AND AN
UPR RDG OVER THE WRN PLAINS. THERE IS A SHRTWV EMBEDDED IN THIS FLOW
THAT IS DIVING THRU ERN LK SUP...BUT THE MID LVLS ARE SUFFICIENTLY
DRY/STABLE OVER THE UPR LKS PER THE 12Z INL/YPL RAOBS THAT THERE
HAVE BEEN NO SHOWERS. BUT THESE RAOBS ALL SHOW A GOOD DEAL OF LLVL
MSTR. WITH THE ONSET OF DAYTIME HEATING...A GOOD DEAL OF LO CLD
DVLPD...ESPECIALLY OVER THE W AND NCENTRAL WHERE THE SFC-H925 NLY
FLOW UPSLOPES OFF LK SUP. THE STEADY/GUSTY N WIND IS CAUSING HIER
WAVES/DANGEROUS SWIMMING CONDITIONS IN THE LK SUP BEACHES E OF THE
KEWEENAW. CLOSER TO HI PRES OVER FAR NW ONTARIO WHERE THE LLVL
AIRMASS IS MUCH DRIER AS SHOWN ON THE 12Z CHURCHILL MANITOBA
RAOB...THERE ARE FEWER CLDS AND WINDS ARE LGT.
MAIN FCST CONCERNS IN THE SHORT TERM ARE CLD TRENDS THIS AFTN AND
THEN TEMPS TNGT AND THU AS THE DRY HI PRES IN ONTARIO WL DOMINATE.
LATE THIS AFTN/TNGT...UNDER CONFLUENT NW FLOW ALF/DEEP LYR QVECTOR
DVGC...SFC HI PRES OVER FAR NW ONTARIO IS PROGGED TO SINK OVER WRN
LK SUP BY 12Z THU. WITH LOSS OF DAYTIME HEATING AND LLVL DRY ADVCTN
IN THE LLVL NLY FLOW AHEAD OF THE SFC HI PRES...EXPECT ANY LINGERING
CLDS TO DISSIPATE THIS EVNG AND GIVE TO MOCLR SKIES OVERNGT. THE
ARRIVAL OF DRIER AIR FM THE N...WITH PWAT SINKING AS LO AS 0.33 INCH
OR 30-35 PCT OF NORMAL...FAVORS A LARGE DIURNAL DROP OF TEMP...
ESPECIALLY OVER THE W WHERE THE WINDS WL BE LIGHTER CLOSER TO THE
INCOMING SFC RDG AXIS. WL MAINTAIN FCST LO TEMPS IN THE 30S AT THE
COLDER INTERIOR LOCATIONS IN THIS AREA. STEADY N WIND OVER THE E
UNDER THE SHARPER PRES GRADIENT BTWN THE RDG AND LO PRES OVER QUEBEC
WL TEND TO RESTRICT THE DIURNAL TEMP DROP THERE.
THU...SFC HI PRES AXIS IS FCST TO SHIFT FM NCENTRAL UPR MI THRU LK
MI. WITH CORE OF DRY AIR OVHD...EXPECT NOTHING MORE THAN SOME
DIURNAL CU OVER THE INTERIOR. H85 TEMPS ARE FCST TO PEAK BTWN ABOUT
8C OVER THE E TO 12C OVER THE W. MIXING TO H8 ON FCST SDNGS
INDICATES MAX TEMPS WL PEAK NEAR 75 OVER THE INTERIOR W AND
SCENTRAL. WITH A STEADY NW WIND OFF LK SUP OVER THE E THAT WL
MAINTAIN HIER WAVES/SWIM RISK...TEMPS WL HAVE A HARD TIME RISING
OVER 70 EXCEPT CLOSER TO LK MI. AFTN MIXING WL CAUSE MIN RH TO
BOTTOM OUT AS LO AS 30-35 PCT OVER MUCH OF THE INTERIOR. DESPITE THE
SOMEWHAT COOLER TEMPS OVER THE E...STRONGER WINDS WL AGGRAVATE FIRE
WX CONDITIONS THERE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 317 AM EDT THU AUG 14 2014
FOR THE TIME BEING...MODELS ARE IN GOOD AGREEMENT THROUGH MUCH OF
THE FORECAST PERIOD. THE CWA WILL BE UNDER NW FLOW ALOFT FRI INTO
SUN BEFORE AN UPPER RIDGE PASSES OVERHEAD LATE SUN INTO MON...THEN
AN UPPER TROUGH MOVES INTO THE AREA THE REGION TUE INTO WED. HAVE
GOOD CONFIDENCE THROUGH THE WEEKEND...BUT MODELS HAVE SHOWN POOR RUN
TO RUN CONTINUITY NEXT WEEK.
MODELS HAVE TRENDED DRIER ON FRI FOR THE CWA AS THEY DEPICT BEST
FORCING BEING W OF THE CWA AS A SHORTWAVE MOVES THROUGH THE NW FLOW.
WILL CONTINUE TO SHOW SLIGHT CHANCE POPS GIVEN MARGINAL INSTABILITY
/MLCAPE VALUES LESS THAN 500 J/KG/ AND UNCERTAINTY IN THE TRACK OF ANY
SHORTWAVES.
A STRONGER SHORTWAVE AND ASSOCIATED SFC COLD FRONT WILL MOVES
ACROSS THE CWA FRI INTO INTO SAT...BRINGING GREATER CHANCES FOR
PRECIP. WILL FAVOR THE NERN HALF OF THE CWA WITH THE GREATEST POPS
AS MODELS INDICATE BEST FORCING WILL EXIST THERE.
A SFC HIGH MOVES INTO THE REGION ALONG AND AHEAD OF THE UPPER
RIDGE...WHICH SHOULD LEAD TO DRY CONDITIONS SUN THROUGH MON...BEFORE
PRECIP CHANCES INCREASE MON NIGHT INTO WED.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 737 PM EDT WED AUG 13 2014
A DRY AIR MASS ASSOCIATED WITH HIGH PRES BUILDING OVER THE UPPER
GREAT LAKES WILL RESULT IN VFR CONDITIONS PREVAILING AT
KIWD/KCMX/KSAW THRU THIS FCST PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 331 PM EDT WED AUG 13 2014
UNDER A SHARP PRES GRADIENT BETWEEN HI PRES SINKING SOUTH THRU FAR
WESTERN ONTARIO AND SLOW MOVING LO PRES IN WESTERN QUEBEC...EXPECT N
TO NW WINDS AS HI AS 20-25 KTS OVER THE E HALF OF LAKE SUPERIOR THRU
THU. AS THE ONTARIO HI MOVES OVER THE UPPER LAKES LATER ON THU...
EXPECT WINDS TO DIMINISH UNDER 15 KTS BY FRI. THESE LIGHTER WINDS
WILL PERSIST INTO SAT...BUT THE SHARPENING PRES GRADIENT BEHIND A
COLD FRONTAL PASSAGE WILL CAUSE N-NE WINDS TO INCREASE UP TO 20 KTS
ON SAT NIGHT INTO SUN. AS THE HI PRES TRAILING THE FRONT SLIDES TO
THE SE EARLY NEXT WEEK...WINDS WILL SHIFT TO THE SSE UP TO 20 KTS ON
MON.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...ROLFSON
MARINE...KC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1104 PM CDT FRI AUG 15 2014
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 357 PM CDT FRI AUG 15 2014
RAIN HAS PUSHED WELL TO THE SOUTH INTO IOWA THIS AFTERNOON FROM
SOUTHWESTERN MN THIS MORNING. CONSIDERABLE CLOUDINESS CONTINUES...
PARTICULARLY OVER WRN MN WHERE LOWER CLOUDS ARE BEING OBSERVED IN
RICHER LOW LEVEL MOISTURE...WITH MORE FAIR WX CU ACROSS ERN MN
AND WRN WI. DEW POINTS HAVE RISEN A GOOD 5 TO 15 DEGREES ACROSS
THE CWA SINCE YESTERDAY AFTERNOON WITH WAA EXPECTED TO CONTINUE
THROUGH SATURDAY. MODELS ARE A BIT AT ODDS WITH RESPECT TO FOG AND
LOW STRATUS TONIGHT WITH THE HI-RES MODELS INCLUDING THE
HRRR...HOPWRF...AND RAP NOT SHOWING TOO MUCH...WHILE FORECAST
SOUNDINGS OF THE NAM AND GFS AND THEIR MOS PRODUCTS INDICATING MUCH
MORE IN THE WAY OF RICH BOUNDARY LAYER MOISTURE. GIVEN THE RECENT
DRY SPELL...I AM HESITANT TO BUY INTO WIDESPREAD DENSE FOG AND AM
THINKING MORE LOW CLOUD FORMATION...ESPECIALLY IF 15-20 KT WINDS
AROUND 1KFT VERIFIES. DID ADD AREAS OF FOG INTO THE GRIDS...BUT AT
THIS POINT IT SHOULD NOT BE ANYTHING TOO SIGNIFICANT OUTSIDE OF
AVIATION INTERESTS.
TONIGHT AND MOST OF SATURDAY IS LOOKING DRY. LITTLE IN THE WAY OF
FORCING WILL PRECLUDE DEVELOPMENT UNTIL SATURDAY AFTERNOON IN
CENTRAL MN AND NWRN WI WHEN A WEAK COOL FRONT ADVANCES SOUTH FROM
NORTHERN MINNESOTA AND LAKE SUPERIOR. THERE WILL BE A SECONDARY
AREA OF FORCING ACROSS SOUTHWESTERN MN WHERE A WEAK VORTICITY MAX
PUSHES IN DURING THE LATE AFTERNOON. HOWEVER...MID LEVEL RIDGING
WILL ALSO BE IN PLACE WHICH SHOULD LIMIT THE OVERALL COVERAGE TO
SLIGHT CHC TO LOW CHC RANGE INTO EVENING.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 357 PM CDT FRI AUG 15 2014
FOR THE LONG TERM...BEST CHANCE FOR PRECIP STILL LOOKS TO COME
MONDAY INTO TUESDAY...WHERE ONE WILL CONTINUE TO FIND LIKELY POPS.
AFTER THAT...MODEL DISAGREEMENT STARTS TO INCREASE
APPRECIABLY...THOUGH WE ARE STILL SEEING THE IDEA OF A TROUGH
SETTING UP ACROSS THE NORTHERN ROCKIES...THERE ARE JUST SIGNIFICANT
TIMING DIFFERENCES AS TO WHEN ENERGY FROM SAID TROUGH WORKS ACROSS
THE NORTHERN PLAINS.
WE WILL BE STARTING OFF THIS PERIOD WITH HIGH PRESSURE AGAIN
BUILDING SOUTH ACROSS THE GREAT LAKES FROM WESTERN ONTARIO. THIS
WILL PUSH A WEAK COLD INTO SW MN SATURDAY NIGHT...HELPING CONFINE
THE INSTABILITY THROUGH SUNDAY INTO SW MN AS WELL...AS DRIER AIR
WORKS IN FROM THE NORTHEAST. HAVE MAINTAINED SOME 20 POPS OUT IN SW
MN FOR AREAS THAT ARE EXPECTED TO BE NEAR THE BOUNDARY. HAVE GONE NO
HIGHER THAN THAT WITH POPS AS OUTSIDE OF THAT WEAK SFC
BOUNDARY...THE FORCING IS NIL AS AN H5 ANTICYCLONE WILL BE DRIFTING
OVER MN...WITH NO LLJ SUPPORT TO SPEAK OF EITHER WITH H85 RIDGING
MOVING THROUGH AS WELL.
FOR MONDAY...PRECIP CHANCES WILL BE ON THE INCREASE AS THE UPPER LOW
CURRENTLY SPINNING ACROSS WASHINGTON WORKS THROUGH THE RIDGE AND
COMES DIVING ACROSS MN MONDAY AND ACROSS WI TUESDAY. THIS HAS BEEN A
FAIRLY STABLE SIGNAL IN THE MODELS THE PAST FEW DAYS...SO CONTINUED
TO RUN WITH LIKELY POPS...THOUGH SLOWED THEIR EWRD PROGRESSION
ACROSS THE AREA SUNDAY NIGHT INTO MONDAY...AS ONCE AGAIN WE WILL
HAVE VERY DRY HIGH PRESSURE OVER THE GREAT LAKES HELPING TO SLOW THE
EWRD PROGRESSION OF MOISTURE/PRECIP WITH THIS SYSTEM. STILL LOOKS
GOOD FOR A WIDESPREAD QUARTER TO ONE INCH WITH THIS SYSTEM...BUT
DOES NOT LOOK LIKE HEAVY PRECIP WILL BE MUCH OF A THREAT...AS
MOISTURE TRANSPORT DOES NOT LOOK TO GET CARRIED AWAY...WITH THE LLJ
ONLY TOPPING OUT AROUND 20 KTS...AND THE PW PLUME ASSOCIATED WITH
THIS PRECIP WILL ONLY BE AROUND 1.5 INCHES. WE JUST LOOK TO HAVE
GOOD UPPER DIFFLUENCE AND FORCING WITH THE H5 WAVE DROPPING ACROSS
THE AREA. SEVERE THREAT LOOKS MINIMAL AS WELL AS BOTH THERMODYNAMIC
AND KINEMATIC FIELDS LOOK WEAK...JUST LOOKS LIKE SOME MUCH NEEDED
LIGHT-MODERATE RAIN AT THIS POINT.
FROM TUESDAY AND BEYOND...MODEL DISCREPANCIES INCREASE QUITE A BIT
WITH THE WAVE AS IT MOVES FROM MN TOWARD THE GREAT LAKES. THE
GEM/GFS MAINTAIN A DEEPER/STRONGER UPPER WAVE ACROSS MN/WI...WHILE
THE ECMWF ALLOWS IT TO GET ABSORBED INTO THE MAIN BELT OF
WESTERLIES. THIS DIFFERENCE IN TURN INFLUENCES HOW THE MODELS BEGIN
TO BRING THE DEVELOPING TROUGH IN THE NRN ROCKIES OUT INTO THE
PLAINS. THE GEM/GFS SOLUTION KEEPS THE UPPER LOW OVER THE GREAT
LAKES LONGER...WHICH IN TURN KEEPS ENERGY WITH THE WRN TROUGH HELD
UP OUT WEST UNTIL THE WEEKEND. THE ECMWF ALLOWS FOR A MUCH MORE
PROGRESSIVE PATTERN WITH RESPECT TO THE TROUGH...BRINGING PIECES OF
THE TROUGH ACROSS THE UPPER MS VALLEY ON THURSDAY AND AGAIN OVER THE
WEEKEND. THE GFS/GEM SOLUTION WOULD KEEP ANY ENERGY FROM THE WRN
TROUGH GETTING HERE UNTIL THE WEEKEND...WITH WEDNESDAY THROUGH
FRIDAY OF NEXT WEEK BEING MAINLY DRY AS WE STAY UNDER MORE OF THE
INFLUENCE OF AN UPPER RIDGE...AS THE INFLUENCE OF THE UPPER THROUGH
REMAINS TO THE NORTHWEST. GIVEN THE SPREAD IN MODELS...KEPT CLOSE TO
GFS/ECMWF BLEND FOR POPS...WHICH MEANS POPS TUESDAY ARE MAINLY TO
THE EAST /CLOSER TO THE UPPER LOW/...WEDNESDAY IS MAINLY DRY...WHILE
THU/FRI SEES THE RETURN OF 20-30 POPS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1104 PM CDT FRI AUG 15 2014
CONFIDENCE REMAINS PRETTY HIGH ON LOW MVFR/IFR CEILINGS AND
VISIBILITIES OVERNIGHT AND EARLY SATURDAY MORNING AT THE TAF
SITES. TEMP/DEW POINT SPREADS ARE ALREADY QUITE CLOSE AT THE MN
TAF SITES BUT THERE HAS ALSO BEEN SOME CEILINGS FROM 040 TO 090
SPROUT ACROSS WEST CENTRAL MN IN THE PAST TWO HOURS. IT REMAINS
CLEAR ACROSS SOUTHERN MN AND WEST CENTRAL WI. CEILINGS ARE
DETERIORATING ACROSS NORTHERN IA WITH SOME INDICATION OF THE
STRATUS BUILDING NORTHWARD. HENCE...THE SOUTHWEST AND SOUTH
CENTRAL AREAS OF MN WILL LIKELY DEVELOP WIDESPREAD CEILINGS AT OR
BELOW 010 IN THE NEXT FEW HOURS. SHORT TERM SOLUTIONS SHOW THIS
TRYING TO ADVECT INTO THE TWIN CITIES AND WEST CENTRAL WI BEFORE
DAYBREAK. THEREFORE...PRETTY MUCH KEPT THE LOW CEILING FORECASTS
IN PLACE WITH A LITTLE UPWARD ADJUSTMENT TO THE VISIBILITIES
ACROSS CENTRAL MN WITH CEILINGS BEING MORE DOMINATE. ANOTHER
CONCERN IS THE SHRA/TSRA CHANCES LATE SATURDAY AFTERNOON/EVENING.
NAM FORECAST SOUNDINGS REMAIN VERY MOIST ALONG THE COLD FRONT
ALONG WITH LIGHT WINDS IN THE VERTICAL. CONVECTION THAT DOES DEVELOP
WILL BE SLOW MOVING AND MAY PRODUCE TORRENTIAL DOWNPOURS.
CONSENSUS IS NOT VERY GOOD AMONG THE WRF MEMBERS AT THIS TIME WITH
VCSH INDICATED AT THIS TIME. LIGHT SOUTH WINDS OVERNIGHT. LIGHT
AND VARIABLE WINDS SATURDAY MORNING BECOMING NORTHEAST DURING THE
AFTERNOON AND EVENING.
KMSP...STRATUS WILL ARRIVE FROM THE SOUTH BEFORE DAYBREAK AND LAST
INTO THE MID MORNING HOURS. SCT-BKN VFR CONDITIONS IN THE
AFTERNOON WITH SHRA/TSRA CHANCES DURING THE EVENING...ALTHOUGH
CONFIDENCE IN THE PRECIP CHANCES IN THE EVENING IS LOW.
/OUTLOOK FOR KMSP/
SUN...VFR. WIND E 5-10 KTS.
MON...VFR/MVFR WITH TSRA LIKELY AFTN/NIGHT. WINDS S 5-10 KTS.
TUE...VFR/MVFR WITH TSRA POSSIBLE. WIND NW 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...BORGHOFF
LONG TERM...MPG
AVIATION...RAH
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
649 PM CDT FRI AUG 15 2014
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 357 PM CDT FRI AUG 15 2014
RAIN HAS PUSHED WELL TO THE SOUTH INTO IOWA THIS AFTERNOON FROM
SOUTHWESTERN MN THIS MORNING. CONSIDERABLE CLOUDINESS CONTINUES...
PARTICULARLY OVER WRN MN WHERE LOWER CLOUDS ARE BEING OBSERVED IN
RICHER LOW LEVEL MOISTURE...WITH MORE FAIR WX CU ACROSS ERN MN
AND WRN WI. DEW POINTS HAVE RISEN A GOOD 5 TO 15 DEGREES ACROSS
THE CWA SINCE YESTERDAY AFTERNOON WITH WAA EXPECTED TO CONTINUE
THROUGH SATURDAY. MODELS ARE A BIT AT ODDS WITH RESPECT TO FOG AND
LOW STRATUS TONIGHT WITH THE HI-RES MODELS INCLUDING THE
HRRR...HOPWRF...AND RAP NOT SHOWING TOO MUCH...WHILE FORECAST
SOUNDINGS OF THE NAM AND GFS AND THEIR MOS PRODUCTS INDICATING MUCH
MORE IN THE WAY OF RICH BOUNDARY LAYER MOISTURE. GIVEN THE RECENT
DRY SPELL...I AM HESITANT TO BUY INTO WIDESPREAD DENSE FOG AND AM
THINKING MORE LOW CLOUD FORMATION...ESPECIALLY IF 15-20 KT WINDS
AROUND 1KFT VERIFIES. DID ADD AREAS OF FOG INTO THE GRIDS...BUT AT
THIS POINT IT SHOULD NOT BE ANYTHING TOO SIGNIFICANT OUTSIDE OF
AVIATION INTERESTS.
TONIGHT AND MOST OF SATURDAY IS LOOKING DRY. LITTLE IN THE WAY OF
FORCING WILL PRECLUDE DEVELOPMENT UNTIL SATURDAY AFTERNOON IN
CENTRAL MN AND NWRN WI WHEN A WEAK COOL FRONT ADVANCES SOUTH FROM
NORTHERN MINNESOTA AND LAKE SUPERIOR. THERE WILL BE A SECONDARY
AREA OF FORCING ACROSS SOUTHWESTERN MN WHERE A WEAK VORTICITY MAX
PUSHES IN DURING THE LATE AFTERNOON. HOWEVER...MID LEVEL RIDGING
WILL ALSO BE IN PLACE WHICH SHOULD LIMIT THE OVERALL COVERAGE TO
SLIGHT CHC TO LOW CHC RANGE INTO EVENING.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 357 PM CDT FRI AUG 15 2014
FOR THE LONG TERM...BEST CHANCE FOR PRECIP STILL LOOKS TO COME
MONDAY INTO TUESDAY...WHERE ONE WILL CONTINUE TO FIND LIKELY POPS.
AFTER THAT...MODEL DISAGREEMENT STARTS TO INCREASE
APPRECIABLY...THOUGH WE ARE STILL SEEING THE IDEA OF A TROUGH
SETTING UP ACROSS THE NORTHERN ROCKIES...THERE ARE JUST SIGNIFICANT
TIMING DIFFERENCES AS TO WHEN ENERGY FROM SAID TROUGH WORKS ACROSS
THE NORTHERN PLAINS.
WE WILL BE STARTING OFF THIS PERIOD WITH HIGH PRESSURE AGAIN
BUILDING SOUTH ACROSS THE GREAT LAKES FROM WESTERN ONTARIO. THIS
WILL PUSH A WEAK COLD INTO SW MN SATURDAY NIGHT...HELPING CONFINE
THE INSTABILITY THROUGH SUNDAY INTO SW MN AS WELL...AS DRIER AIR
WORKS IN FROM THE NORTHEAST. HAVE MAINTAINED SOME 20 POPS OUT IN SW
MN FOR AREAS THAT ARE EXPECTED TO BE NEAR THE BOUNDARY. HAVE GONE NO
HIGHER THAN THAT WITH POPS AS OUTSIDE OF THAT WEAK SFC
BOUNDARY...THE FORCING IS NIL AS AN H5 ANTICYCLONE WILL BE DRIFTING
OVER MN...WITH NO LLJ SUPPORT TO SPEAK OF EITHER WITH H85 RIDGING
MOVING THROUGH AS WELL.
FOR MONDAY...PRECIP CHANCES WILL BE ON THE INCREASE AS THE UPPER LOW
CURRENTLY SPINNING ACROSS WASHINGTON WORKS THROUGH THE RIDGE AND
COMES DIVING ACROSS MN MONDAY AND ACROSS WI TUESDAY. THIS HAS BEEN A
FAIRLY STABLE SIGNAL IN THE MODELS THE PAST FEW DAYS...SO CONTINUED
TO RUN WITH LIKELY POPS...THOUGH SLOWED THEIR EWRD PROGRESSION
ACROSS THE AREA SUNDAY NIGHT INTO MONDAY...AS ONCE AGAIN WE WILL
HAVE VERY DRY HIGH PRESSURE OVER THE GREAT LAKES HELPING TO SLOW THE
EWRD PROGRESSION OF MOISTURE/PRECIP WITH THIS SYSTEM. STILL LOOKS
GOOD FOR A WIDESPREAD QUARTER TO ONE INCH WITH THIS SYSTEM...BUT
DOES NOT LOOK LIKE HEAVY PRECIP WILL BE MUCH OF A THREAT...AS
MOISTURE TRANSPORT DOES NOT LOOK TO GET CARRIED AWAY...WITH THE LLJ
ONLY TOPPING OUT AROUND 20 KTS...AND THE PW PLUME ASSOCIATED WITH
THIS PRECIP WILL ONLY BE AROUND 1.5 INCHES. WE JUST LOOK TO HAVE
GOOD UPPER DIFFLUENCE AND FORCING WITH THE H5 WAVE DROPPING ACROSS
THE AREA. SEVERE THREAT LOOKS MINIMAL AS WELL AS BOTH THERMODYNAMIC
AND KINEMATIC FIELDS LOOK WEAK...JUST LOOKS LIKE SOME MUCH NEEDED
LIGHT-MODERATE RAIN AT THIS POINT.
FROM TUESDAY AND BEYOND...MODEL DISCREPANCIES INCREASE QUITE A BIT
WITH THE WAVE AS IT MOVES FROM MN TOWARD THE GREAT LAKES. THE
GEM/GFS MAINTAIN A DEEPER/STRONGER UPPER WAVE ACROSS MN/WI...WHILE
THE ECMWF ALLOWS IT TO GET ABSORBED INTO THE MAIN BELT OF
WESTERLIES. THIS DIFFERENCE IN TURN INFLUENCES HOW THE MODELS BEGIN
TO BRING THE DEVELOPING TROUGH IN THE NRN ROCKIES OUT INTO THE
PLAINS. THE GEM/GFS SOLUTION KEEPS THE UPPER LOW OVER THE GREAT
LAKES LONGER...WHICH IN TURN KEEPS ENERGY WITH THE WRN TROUGH HELD
UP OUT WEST UNTIL THE WEEKEND. THE ECMWF ALLOWS FOR A MUCH MORE
PROGRESSIVE PATTERN WITH RESPECT TO THE TROUGH...BRINGING PIECES OF
THE TROUGH ACROSS THE UPPER MS VALLEY ON THURSDAY AND AGAIN OVER THE
WEEKEND. THE GFS/GEM SOLUTION WOULD KEEP ANY ENERGY FROM THE WRN
TROUGH GETTING HERE UNTIL THE WEEKEND...WITH WEDNESDAY THROUGH
FRIDAY OF NEXT WEEK BEING MAINLY DRY AS WE STAY UNDER MORE OF THE
INFLUENCE OF AN UPPER RIDGE...AS THE INFLUENCE OF THE UPPER THROUGH
REMAINS TO THE NORTHWEST. GIVEN THE SPREAD IN MODELS...KEPT CLOSE TO
GFS/ECMWF BLEND FOR POPS...WHICH MEANS POPS TUESDAY ARE MAINLY TO
THE EAST /CLOSER TO THE UPPER LOW/...WEDNESDAY IS MAINLY DRY...WHILE
THU/FRI SEES THE RETURN OF 20-30 POPS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 649 PM CDT FRI AUG 15 2014
CONFIDENCE REMAINS HIGH ON FOG/STRATUS DEVELOPING LATE THIS
EVENING ACROSS THE MN RIVER VALLEY AND SPREADING NORTH AND EAST
THROUGH THE NIGHT AS THE LOW LEVEL FLOW INCREASES FROM THE
SOUTHWEST. LOW MVFR/IFR CEILINGS SATURDAY MORNING GRADUALLY
BECOMING VFR BY LATE MORNING. OVERALL...LITTLE CHANGE IN THE
CURRENT TAF PACKAGE OVER THE PREVIOUS ONE. A COLD FRONT WILL REACH
KAXN AND KSTC NEAR THE END OF THE TAF PERIOD (22Z-24Z). A FEW
SHRA/TSRA ARE POSSIBLE ALONG THE BOUNDARY. THE FRONT AND THE
THREAT OF PRECIPITATION WILL REACH INTO THE TWIN CITIES SATURDAY
EVENING. LIGHT SOUTHERLY WINDS TONIGHT AND SATURDAY MORNING BECOMING
LIGHT SOUTHWEST TO WEST IN THE AFTERNOON AND NORTHERLY IN THE
EVENING.
KMSP...STILL EXPECT LOW MVFR/IFR CEILINGS DURING THE LATE NIGHT
AND MORNING HOURS ON SATURDAY. THE CEILINGS WILL LIFT AND SCT OUT
BY AFTERNOON. SMALL THREAT FOR A SHOWER OR ISOLATED THUNDERSTORM
SATURDAY EVENING AS A COLD FRONT MOVES THROUGH.
/OUTLOOK FOR KMSP/
SUN...VFR. WIND E 5-10 KTS.
MON...VFR/MVFR WITH TSRA LIKELY AFTN/NIGHT. WINDS S 5-10 KTS.
TUE...VFR/MVFR WITH TSRA POSSIBLE. WIND NW 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...BORGHOFF
LONG TERM...MPG
AVIATION...RAH
AREA FORECAST DISCUSSION
NWS GLASGOW MT
727 PM MDT FRI AUG 15 2014
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SUNDAY...
EVENING UPDATE...
LINE OF THUNDERSTORMS TO THE WEST OF THE CWA ON RADAR ARE
EXPECTED TO MOVE THROUGH THE WESTERN HALF OF THE CWA BEFORE
MIDNIGHT. AREA IS STABILIZED OUT FROM AFTERNOON CONVECTION. SO, THE
OVERALL TREND FOR ENTERING THUNDERSTORMS SHOULD BE DOWNWARD
THROUGH MIDNIGHT. POPS WERE UPDATE TO ACCOUNT FOR THIS.
PATCHY FOG IS ALSO BEING HINTED AT BY THE RAP AND HRRR. NAMDNG5
DOES NOT INCLUDE THE POSSIBILITY OF FOG AND WITH SKY COVER HAVING
A HARD TIME CLEARING CONFIDENCE IS LOW AND FOG WILL BE LIMITED IN
COVERAGE. GAH
PREVIOUS SHORT TERM DISCUSSION...
MAIN CHALLENGES THIS PERIOD WAS IF AND HOW MUCH RAIN...AND IF IT
WILL FOG TONIGHT.
TWO SYSTEMS AFFECTING THE CWA. ONE IS A MCS-TYPE DISSIPATING OVER
THE SE ZONES. GFS DOING A HORRIBLE JOB OF THIS ONE TODAY AS IT/S
QPF/S WERE TOO LOW. NAM A BIT BETTER. WITH STEADY RAIN
CONTINUING...SMALL STREAM FLOOD ADVISORY FOR THIS AREA WAS EXTENDED
TILL 630 PM.
ATTENTION THEN TURNS TO THE SECOND SYSTEM...UPPER CLOSED LOW THAT IS
DRIFTING NE INTO THE NORTHERN/CANADIAN ROCKIES. THUNDERSTORMS...SOME
SEVERE...OVER WESTERN MONTANA HAVE FORMED AS A RESULT AND ARE
EXPECTED TO SPREAD INTO CENTRAL MONTANA THIS AFTERNOON. THESE STORMS
SHOULD REACH THE WESTERN ZONES AND COULD BE STRONG.
SINCE GFS DIDN/T PERFORM WELL TODAY...SIDED MORE WITH A NAM/ECMWF
BLEND WITH THINGS THROUGH MOST OF THE PERIOD. 12Z ECMWF SHOWS DECENT
QPF FOR THE SE ZONES THAT WILL HAVE TO BE WATCHED AS SOIL CONDITIONS
ARE NOW VERY WET. OTHERWISE...SHOWERS/THUNDERSTORMS WILL CONTINUE TO
BE SCATTERED ACROSS THE CWA THROUGH THE PERIOD...PROVIDING
BENEFICIAL RAINS TO MOST AREAS. TFJ
.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...
FOUND BEST CONSENSUS FOR UPDATING THE LONG TERM FORECAST THROUGH
WEDNESDAY MORNING. MAIN CONCERN FOR THIS FORECAST PERIOD IS THE
INFLUENCE OF THE LARGE-SCALE UPPER-LEVEL OPEN TROUGH WHICH
DESCENDS SOUTHWARD FROM THE CANADIAN ROCKIES AND SPREADS ACROSS
OUR BORDER WITH THEM THROUGH MOST OF NEXT WEEK. THE SMALLER-SCALE
DETAILS OF SHORT WAVE ENERGY AND TIMING AND PLACEMENT STILL NEED
TO BE WORKED OUT...BUT SOME POTENTIAL EXISTS FOR MORE WIDESPREAD
AND HEAVY RAINFALL...ESPECIALLY TOWARD THE LATTER PART OF NEXT
WEEK.
LATE MONDAY THROUGH EARLY WEDNESDAY SEEMS TO BE A RELATIVELY DRY
PERIOD OF TIME BETWEEN STORM SYSTEMS. THIS WOULD COINCIDE WITH THE
GOOD MODEL CONSENSUS REPRESENTING A SHORT WAVE RIDGE DURING THIS
TIME FRAME. BMICKELSON
PREVIOUS LONG TERM DISCUSSION...UPPER TROUGH/LOW WILL EXIT THE
AREA SUNDAY NIGHT. AS THE TROUGH MOVES TO THE EAST...A SLIGHT
CHANCE OF SHOWERS AND THUNDERSTORMS WILL LINGER IN SOME AREAS IN
SOME AREAS AS WEAK WAVES ARE POSSIBLE IN THE NW FLOW ALOFT BEHIND
THE TROUGH.
MONDAY NIGHT INTO TUESDAY MORNING WILL BE MAINLY DRY WITH THE AREA
BETWEEN SYSTEMS. AN UPPER TROUGH DIGS INTO WESTERN CANADA AND THE
PACIFIC NORTHWEST ON TUESDAY AND WEDNESDAY. THIS WILL BRING
FREQUENT SHORTWAVES WITH INCREASING CHANCES OF SHOWERS AND
THUNDERSTORMS.
THE TROUGH EXPANDS INTO MONTANA ON THURSDAY AND FRIDAY WITH DEEP
MOISTURE EXPECTED. LOOK FOR A GOOD CHANCE OF SHOWERS AND
THUNDERSTORMS. FORRESTER
&&
.AVIATION...
FLIGHT CATEGORY: MAINLY VFR EXPECTED... AS LOW AS ISOLATED IFR
POSSIBLE.
SYNOPSIS: A LARGE-SCALE STORM SYSTEM WILL SLOWLY MOVE THROUGH THE
REGION OVER THE NEXT FEW DAYS. PERIODS OF RAIN SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE. HEAVY RAIN AND IFR CONDITIONS WILL
ACCOMPANY SOME OF THE STRONGER STORMS. EXPECT MAINLY MID-LEVEL SCT CLOUDS
IN BETWEEN THE SHOWERS.
FOG: DUE TO EXCESSIVE RAINFALL... LIMITED PATCHY FOG WILL BE
POSSIBLE THROUGH THE MORNING HOURS WITH ANY CLEARING THAT OCCURS
OVERNIGHT. LOCAL RAP AND HRRR MODELS ARE HINTING AT IFR
VISIBILITIES HOWEVER NAM IS NOT SO CONFIDENCE IS TOO LOW TO
INCLUDE DIRECTLY IN TAFS YET.
AREA WINDS: VARIABLE WINDS AS OUTFLOWS FROM NEARBY STORMS WILL
IMPACT WIND SPEED AND DIRECTION.
GAH/BMICKELSON
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS BILLINGS MT
910 AM MDT THU AUG 14 2014
.UPDATE...
FORECAST IS ON TRACK FOR MUCH OF THE CWA TO RECEIVE SOME RAIN
TODAY. CURRENTLY...SHOWERS EXIST ACROSS OUR WEST AND SOUTH CENTRAL
PARTS...WITH MOVEMENT FROM SOUTH TO NORTH. MAIN MID LEVEL LOW IS
STILL IN CENTRAL WYOMING SO SHOWERS WILL CONTINUE TO FEED IN FROM
THE SOUTH FOR THE NEXT SEVERAL HOURS. HAVE ADJUSTED MORNING POPS
TO LIKELY IN PLACES BASED ON CURRENT RADAR. FOCUS WILLE
EVENTUALLY SHIFT TO OUR EAST THIS AFTERNOON AND EVENING AS MID
LEVEL CIRCULATION LIFTS INTO SOUTHEAST MT. PWATS ARE QUITE HIGH
AND COULD BRING A RISK OF HEAVY RAIN IF IT WERE NOT FOR THE CLOUDY
SKIES AND EARLY ONSET OF SHOWERS. THE EXCEPTION COULD BE IN OUR NE
WHERE SUNNY SKIES IN THE MORNING AND TEMPS TO THE LOW 90S WILL
ALLOW FOR SOME CAPE TO BUILD UP. MODELS CERTAINLY PAINT HIGHEST
QPF IN AN AREA FROM MILES CITY TO BAKER THIS EVENING. WITH THIS IN
MIND HAVE RAISED EVENING POPS TO LIKELY IN THIS AREA. SHEAR WILL
BE RATHER LOW TODAY SO DO NOT SEE A SIGNIFICANT SEVERE RISK...BUT
HEAVY RAIN AND SMALL HAIL A DEFINITE POSSIBILITY NEAR MILES CITY
AND BAKER BY LATE AFTERNOON AND EVENING. SSEO AND HRRR ALSO
SUGGEST GREATER POTENTIAL FOR HIGHER REFLECTIVITIES IN THIS AREA
AS WELL.
OVERALL...TODAY WILL BE BENEFICIAL REGARDING FIRE WEATHER AS MOST
OF THE REGION WILL SEE SHOWERS AND HIGHER HUMIDITY WITHOUT THE
RISK OF FREQUENT LIGHTNING.
JKL
&&
.SHORT TERM...VALID FOR TDY AND FRI...
A WET DAY IS AHEAD FOR MUCH OF SOUTHEASTERN MONTANA AND NORTHERN
WYOMING...
MODELS IN GOOD AGREEMENT IN BRINGING SHORT WAVE ENERGY INTO
NORTHERN WY AND SOUTH CENTRAL MT BY THURSDAY AFTERNOON. MONSOONAL
MOISTURE FETCH DEPICTED ON WATER VAPOR CONTINUES TO RIDE THE
WESTERN SIDE OF THE UPPER LEVEL RIDGE INTO THE NORTHERN ROCKIES.
NAEFS PW ANOMALIES ARE SHOWING STANDARD DEVIATION VALUES GREATER
THAN 2 FOR MUCH OF THE BYZ CWA. IN ADDITION...LATEST HRRR GUIDANCE
DEPICTING WIDESPREAD SHOWER ACTIVITY IN A LINE FROM WHEATLAND
COUNTY DOWN TO SOUTHERN ROSEBUD COUNTY BY MID MORNING.
FURTHER...WPC 6 HOUR PQPF GUIDANCE SHOWS NICE AREA OF >80 PERCENT
PROBABILITY OF MEASURABLE PRECIPITATION OVER MUCH OF THE CWA BY
00 UTC FRIDAY. SO...WITH ALL OF THAT...DECIDED TO CONTINUE WITH
TREND OF RAISING POPS ON TOP OF WHAT PREVIOUS FORECAST ALREADY HAD
ACROSS THE ENTIRE CWA. NOT EXPECTING PRECIPITATION TODAY TO BE
SEVERE IN NATURE...BUT A FEW OF THESE ISOLATED STORMS COULD
PRODUCE HEAVY RAIN AT TIMES. STORMS THAT HAVE DEVELOPED THE PAST
DAY OR SO HAVE SHOWN NICE KDP RETURNS ON RADAR. THIS BEARS
WATCHING AS STORMS THAT FORM OVER BURN SCAR AREAS MAY BE
SUSCEPTIBLE TO DEBRIS FLOWS AND SUCH.
TEMPERATURES SHOULD BE COOLER TODAY...WITH CLOUD COVER AND
PRECIPITATION IN THE AREA...WITH HIGHS IN THE UPPER 80S TO LOW 90S
ACROSS THE PLAINS.
FOR FRIDAY...THE LOW THAT HAS BEEN STALLED OVER THE PAC NW FOR
THE LAST DAY OR SO WILL BEGIN TO MOVE EASTWARD. EVEN THOUGH BEST
FORCING WILL BE TO THE WEST OF THE BYZ CWA...THERE WILL BE ENOUGH
LEFT OVER MONSOONAL MOISTURE TO GENERATE SOME SHOWERS ACROSS THE
REGION. SINGER
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
MODELS WERE IN PRETTY GOOD AGREEMENT THROUGH THE EXTENDED
PACKAGE. THE NORTHWEST UPPER LOW CURRENTLY OVER NORTH CENTRAL
OREGON IS PROGGED TO SLIDE ACROSS NORTHERN MONTANA THIS WEEKEND.
DEEPEST INSTABILITY WILL BE OVER SOUTHEAST MONTANA ON SATURDAY AS
THESE LOCATIONS WILL BE EAST OF A SURFACE TROUGH. THE SURFACE
TROUGH WILL SLIDE EAST ON SUNDAY FOR A LESSENING CHANCE OF
CONVECTION. THE FLOW DRIES OUT SOME FOR MONDAY AND TUESDAY AS IT
BACKS TO THE NORTHWEST. HEIGHTS WILL FALL FOR WEDNESDAY AND
THURSDAY AS AN UPPER TROUGH DROPS SOUTHEAST FROM SOUTHWEST CANADA.
THIS WILL INCREASE THE CHANCE OF SHOWERS AND THUNDERSTORMS. TWH
&&
.AVIATION...
SHOWERS ARE SPREADING NORTH FROM WYOMING THIS MORNING...AND HAVE
STARTED TO IMPACT KSHR/KLVM/KBIL. THE SHOWERS WILL CONTINUE TO
SPREAD NORTH AND EAST...IMPACTING KMLS/KBHK BY MID AFTERNOON.
LOCALIZED MVFR/IFR CONDITIONS CON BE EXPECTED IN HEAVIER RAIN
SHOWERS. THE BEST POTENTIAL FOR THUNDERSTORMS WILL OCCUR OVER THE
EAST AND SOUTHEAST ROUTES THIS AFTERNOON/EVENING. PRECIP WILL BE
HEAVIER IN THUNDERSTORMS...RESULTING IN LOCALIZED IFR/LIFR FLIGHT
CONDITIONS. AAG
&&
.PRELIMINARY POINT TEMP/POPS...
TDY FRI SAT SUN MON TUE WED
-------------------------------------------------------
BIL 083 064/089 062/088 061/088 061/087 061/091 061/087
6/T 43/T 32/T 22/T 21/B 11/U 12/T
LVM 086 055/088 053/087 052/088 052/086 053/088 053/086
6/T 54/T 42/T 22/T 22/T 21/B 12/T
HDN 085 061/090 059/090 058/090 058/089 058/093 058/090
6/T 43/T 32/T 22/T 21/B 11/B 12/T
MLS 092 065/087 063/090 061/089 061/088 061/091 062/089
6/T 64/T 44/T 42/T 21/B 11/B 12/T
4BQ 088 065/087 062/089 060/089 059/088 059/090 060/090
6/T 64/T 43/T 33/T 31/B 11/B 12/T
BHK 093 062/085 060/087 056/086 056/085 055/087 057/087
5/T 64/T 45/T 43/T 31/B 11/B 12/T
SHR 082 058/089 056/089 054/088 054/086 054/088 055/087
6/T 43/T 32/T 22/T 21/B 11/U 12/T
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
305 AM MDT THU AUG 14 2014
.SHORT TERM...VALID FOR TDY AND FRI...
A WET DAY IS AHEAD FOR MUCH OF SOUTHEASTERN MONTANA AND NORTHERN
WYOMING...
MODELS IN GOOD AGREEMENT IN BRINGING SHORT WAVE ENERGY INTO
NORTHERN WY AND SOUTH CENTRAL MT BY THURSDAY AFTERNOON. MONSOONAL
MOISTURE FETCH DEPICTED ON WATER VAPOR CONTINUES TO RIDE THE
WESTERN SIDE OF THE UPPER LEVEL RIDGE INTO THE NORTHERN ROCKIES.
NAEFS PW ANOMALIES ARE SHOWING STANDARD DEVIATION VALUES GREATER
THAN 2 FOR MUCH OF THE BYZ CWA. IN ADDITION...LATEST HRRR GUIDANCE
DEPICTING WIDESPREAD SHOWER ACTIVITY IN A LINE FROM WHEATLAND
COUNTY DOWN TO SOUTHERN ROSEBUD COUNTY BY MID MORNING.
FURTHER...WPC 6 HOUR PQPF GUIDANCE SHOWS NICE AREA OF >80 PERCENT
PROBABILITY OF MEASURABLE PRECIPITATION OVER MUCH OF THE CWA BY
00 UTC FRIDAY. SO...WITH ALL OF THAT...DECIDED TO CONTINUE WITH
TREND OF RAISING POPS ON TOP OF WHAT PREVIOUS FORECAST ALREADY HAD
ACROSS THE ENTIRE CWA. NOT EXPECTING PRECIPITATION TODAY TO BE
SEVERE IN NATURE...BUT A FEW OF THESE ISOLATED STORMS COULD
PRODUCE HEAVY RAIN AT TIMES. STORMS THAT HAVE DEVELOPED THE PAST
DAY OR SO HAVE SHOWN NICE KDP RETURNS ON RADAR. THIS BEARS
WATCHING AS STORMS THAT FORM OVER BURN SCAR AREAS MAY BE
SUSCEPTIBLE TO DEBRIS FLOWS AND SUCH.
TEMPERATURES SHOULD BE COOLER TODAY...WITH CLOUD COVER AND
PRECIPITATION IN THE AREA...WITH HIGHS IN THE UPPER 80S TO LOW 90S
ACROSS THE PLAINS.
FOR FRIDAY...THE LOW THAT HAS BEEN STALLED OVER THE PAC NW FOR
THE LAST DAY OR SO WILL BEGIN TO MOVE EASTWARD. EVEN THOUGH BEST
FORCING WILL BE TO THE WEST OF THE BYZ CWA...THERE WILL BE ENOUGH
LEFT OVER MONSOONAL MOISTURE TO GENERATE SOME SHOWERS ACROSS THE
REGION. SINGER
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
MODELS WERE IN PRETTY GOOD AGREEMENT THROUGH THE EXTENDED
PACKAGE. THE NORTHWEST UPPER LOW CURRENTLY OVER NORTH CENTRAL
OREGON IS PROGGED TO SLIDE ACROSS NORTHERN MONTANA THIS WEEKEND.
DEEPEST INSTABILITY WILL BE OVER SOUTHEAST MONTANA ON SATURDAY AS
THESE LOCATIONS WILL BE EAST OF A SURFACE TROUGH. THE SURFACE
TROUGH WILL SLIDE EAST ON SUNDAY FOR A LESSENING CHANCE OF
CONVECTION. THE FLOW DRIES OUT SOME FOR MONDAY AND TUESDAY AS IT
BACKS TO THE NORTHWEST. HEIGHTS WILL FALL FOR WEDNESDAY AND
THURSDAY AS AN UPPER TROUGH DROPS SOUTHEAST FROM SOUTHWEST CANADA.
THIS WILL INCREASE THE CHANCE OF SHOWERS AND THUNDERSTORMS. TWH
&&
.AVIATION...
SHOWERS WILL SPREAD NORTH FROM WYOMING THIS MORNING AND ENTER
KSHR/KBIL/KLVM BY 16Z. THE SHOWERS WILL SPREAD NORTHWARD TOWARD
KMLS AND KBHK BY 20Z. THE HEAVIER SHOWERS WILL PRODUCE LOCAL MVFR
CONDITIONS WITH BRIEF HEAVY RAIN POSSIBLE. THE BEST CHANCE FOR
THUNDERSTORM DEVELOPMENT WILL BE OVER SOUTHEAST MONTANA THIS
AFTERNOON. THE BEST CHANCE OF SHOWERS WILL SHIFT OUT OF SOUTH
CENTRAL MONTANA AND INTO SOUTHEAST MONTANA THIS EVENING. TWH
&&
.PRELIMINARY POINT TEMP/POPS...
TDY FRI SAT SUN MON TUE WED
-------------------------------------------------------
BIL 087 064/089 062/088 061/088 061/087 061/091 061/087
6/T 43/T 32/T 22/T 21/B 11/U 12/T
LVM 086 055/088 053/087 052/088 052/086 053/088 053/086
5/T 54/T 42/T 22/T 22/T 21/B 12/T
HDN 088 061/090 059/090 058/090 058/089 058/093 058/090
6/T 43/T 32/T 22/T 21/B 11/B 12/T
MLS 094 065/087 063/090 061/089 061/088 061/091 062/089
6/T 44/T 44/T 42/T 21/B 11/B 12/T
4BQ 092 065/087 062/089 060/089 059/088 059/090 060/090
6/T 64/T 43/T 33/T 31/B 11/B 12/T
BHK 093 062/085 060/087 056/086 056/085 055/087 057/087
5/T 44/T 45/T 43/T 31/B 11/B 12/T
SHR 084 058/089 056/089 054/088 054/086 054/088 055/087
6/T 43/T 32/T 22/T 21/B 11/U 12/T
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1212 PM CDT THU AUG 14 2014
.UPDATE...
ISSUED AT 958 AM CDT THU AUG 14 2014
UPDATED FORECAST TO INCREASE CLOUD COVER A BIT BASED ON RECENT
SATELLITE TRENDS. ALSO CONSIDERED A SLIGHT CHANCE OF SHOWERS TO
THE FAR NORTHERN FORECAST AREA AS A CLUSTER OF CONVECTION
CONTINUES TO MOVE THROUGH EASTERN SOUTH DAKOTA. RADAR TRENDS
SUGGEST PRECIP IS HAVING A HARD TIME PUSHING SOUTHEAST. LATEST
RUNS OF THE RAP MODEL ALSO KEEP RAIN OUT OF THE FORECAST AREA AND
THIS SEEMS REASONABLE. WILL CONTINUE TO MONITOR TO SEE IF ANYTHING
MIGHT DEVELOP THERE THROUGH PEAK HEATING...BASED ON 12Z NAM.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 316 AM CDT THU AUG 14 2014
MAIN FORECAST CONCERN IS TIMING/CHANCES OF PCPN THROUGH THE WEEKEND.
UPPER RIDGE AXIS CONTINUES TO MOVE EAST...EXTENDING FROM WESTERN
TEXAS NORTHWARD INTO WESTERN NEB AND THE WESTERN DAKOTAS.
SATELLITE IMAGERY SHOWS UPPER SHORTWAVE TROUGH MOVING NORTHEAST
NEAR THE FOUR CORNERS REGION AND THIS WILL CONTINUE TO RIDE UP THE
THE RIDGE AND INTO WESTERN SD/NEB BY 00Z TONIGHT. AT THE
SURFACE...A LARGE RIDGE OF HIGH PRESSURE EXTENDING ACROSS THE
MIDWEST WILL CONTINUE TO SLOWLY MOVE EAST BRINGING PREVAILING
SOUTHEASTERLY SFC FLOW OVER MUCH OF THE CENTRAL PLAINS TODAY. IN
ADDITION...AN ELONGATED REGION OF LEE SIDE LOW PRESSURE EXTENDS
ACROSS THE HIGH PLAINS AHEAD OF THE APPROACHING SHORTWAVE TROUGH.
AS THE UPPER SHORTWAVE TOPS THE RIDGE...THE LEE SIDE LOW WILL ALSO
ADVANCE EAST...SLIDING INTO CENTRAL NEB BY FRIDAY MORNING.
INCREASING ISENTROPIC UPGLIDE AHEAD OF THIS COULD PRODUCE A FEW
SHOWERS AND ISOLATED THUNDERSTORMS...ESPECIALLY WITH A
STRENGTHENING SOUTHWESTERLY LOW LEVEL JET. WE MAY JUST SEE AN
INCREASE OF MID CLOUDS/ACCAS. SPOTTY SHOWERS LOOK MORE PROBABLE
BY FRIDAY AFTERNOON AND EVENING IN ADVANCE OF THE APPROACHING
SHORTWAVE. ONCE THE WAVE IS OVERHEAD IN EASTERN NEBRASKA...IT WILL
DEEPEN AND CLOSE OFF AS IT MOVES INTO NORTHERN MISSOURI. PLACEMENT
AND TIMING OF THIS FEATURE HAS BECOME MORE CONSISTENT IN VARIOUS
MODEL SOLUTIONS SO FORECAST CONFIDENCE IS INCREASING. BY 12Z
SATURDAY...THE UPPER WAVE IS PROGGED TO MOVE OVER NORTHEAST
NEBRASKA WITH THE ASSOCIATED SFC LOW CENTERED SOMEWHERE OVER
EASTERN NEBRASKA. HEAVIER PCPN IS LIKELY ALONG THE WARM FRONT
WHICH SHOULD EXTEND INTO WESTERN IOWA SO HAVE INCREASED POPS IN
SERN NEB AND SWRN IA. AS THE SYSTEM MOVES INTO NORTHERN MISSOURI
SATURDAY AFTERNOON...WE SHOULD SEE LINGERING SHOWERS ON THE
BACKSIDE OF THE SYSTEM ALONG WITH CLOUD COVER AND COOLER TEMPS.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 316 AM CDT THU AUG 14 2014
THERE REMAINS A CHANCE OF PCPN IN NEARLY EVERY FORECAST PERIOD IN
THE EXTENDED AS ADDITIONAL PIECES OF SHORTWAVE ENERGY MOVE ACROSS
THE FLATTENED UPPER LEVEL FLOW. TIMING OF THESE FEATURES IS PRETTY
TOUGH THIS FAR OUT...BUT CANNOT RULE OUT ANY ONE GIVEN PERIOD.
&&
.AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1210 PM CDT THU AUG 14 2014
VFR CONDITIONS THROUGH THE PERIOD WITH SOUTHEASTERLY WINDS AND
MID CLOUDS. COULD SEE A 30 PERCENT CHANCE OF SHOWERS AT KOFK
09-12Z AND KOMA 14-18Z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
UPDATE...DEWALD
SHORT TERM...KERN
LONG TERM...KERN
AVIATION...DEWALD
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1001 AM CDT THU AUG 14 2014
.UPDATE...
ISSUED AT 958 AM CDT THU AUG 14 2014
UPDATED FORECAST TO INCREASE CLOUD COVER A BIT BASED ON RECENT
SATELLITE TRENDS. ALSO CONSIDERED A SLIGHT CHANCE OF SHOWERS TO
THE FAR NORTHERN FORECAST AREA AS A CLUSTER OF CONVECTION
CONTINUES TO MOVE THROUGH EASTERN SOUTH DAKOTA. RADAR TRENDS
SUGGEST PRECIP IS HAVING A HARD TIME PUSHING SOUTHEAST. LATEST
RUNS OF THE RAP MODEL ALSO KEEP RAIN OUT OF THE FORECAST AREA AND
THIS SEEMS REASONABLE. WILL CONTINUE TO MONITOR TO SEE IF ANYTHING
MIGHT DEVELOP THERE THROUGH PEAK HEATING...BASED ON 12Z NAM.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 316 AM CDT THU AUG 14 2014
MAIN FORECAST CONCERN IS TIMING/CHANCES OF PCPN THROUGH THE WEEKEND.
UPPER RIDGE AXIS CONTINUES TO MOVE EAST...EXTENDING FROM WESTERN
TEXAS NORTHWARD INTO WESTERN NEB AND THE WESTERN DAKOTAS.
SATELLITE IMAGERY SHOWS UPPER SHORTWAVE TROUGH MOVING NORTHEAST
NEAR THE FOUR CORNERS REGION AND THIS WILL CONTINUE TO RIDE UP THE
THE RIDGE AND INTO WESTERN SD/NEB BY 00Z TONIGHT. AT THE
SURFACE...A LARGE RIDGE OF HIGH PRESSURE EXTENDING ACROSS THE
MIDWEST WILL CONTINUE TO SLOWLY MOVE EAST BRINGING PREVAILING
SOUTHEASTERLY SFC FLOW OVER MUCH OF THE CENTRAL PLAINS TODAY. IN
ADDITION...AN ELONGATED REGION OF LEE SIDE LOW PRESSURE EXTENDS
ACROSS THE HIGH PLAINS AHEAD OF THE APPROACHING SHORTWAVE TROUGH.
AS THE UPPER SHORTWAVE TOPS THE RIDGE...THE LEE SIDE LOW WILL ALSO
ADVANCE EAST...SLIDING INTO CENTRAL NEB BY FRIDAY MORNING.
INCREASING ISENTROPIC UPGLIDE AHEAD OF THIS COULD PRODUCE A FEW
SHOWERS AND ISOLATED THUNDERSTORMS...ESPECIALLY WITH A
STRENGTHENING SOUTHWESTERLY LOW LEVEL JET. WE MAY JUST SEE AN
INCREASE OF MID CLOUDS/ACCAS. SPOTTY SHOWERS LOOK MORE PROBABLE
BY FRIDAY AFTERNOON AND EVENING IN ADVANCE OF THE APPROACHING
SHORTWAVE. ONCE THE WAVE IS OVERHEAD IN EASTERN NEBRASKA...IT WILL
DEEPEN AND CLOSE OFF AS IT MOVES INTO NORTHERN MISSOURI. PLACEMENT
AND TIMING OF THIS FEATURE HAS BECOME MORE CONSISTENT IN VARIOUS
MODEL SOLUTIONS SO FORECAST CONFIDENCE IS INCREASING. BY 12Z
SATURDAY...THE UPPER WAVE IS PROGGED TO MOVE OVER NORTHEAST
NEBRASKA WITH THE ASSOCIATED SFC LOW CENTERED SOMEWHERE OVER
EASTERN NEBRASKA. HEAVIER PCPN IS LIKELY ALONG THE WARM FRONT
WHICH SHOULD EXTEND INTO WESTERN IOWA SO HAVE INCREASED POPS IN
SERN NEB AND SWRN IA. AS THE SYSTEM MOVES INTO NORTHERN MISSOURI
SATURDAY AFTERNOON...WE SHOULD SEE LINGERING SHOWERS ON THE
BACKSIDE OF THE SYSTEM ALONG WITH CLOUD COVER AND COOLER TEMPS.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 316 AM CDT THU AUG 14 2014
THERE REMAINS A CHANCE OF PCPN IN NEARLY EVERY FORECAST PERIOD IN
THE EXTENDED AS ADDITIONAL PIECES OF SHORTWAVE ENERGY MOVE ACROSS
THE FLATTENED UPPER LEVEL FLOW. TIMING OF THESE FEATURES IS PRETTY
TOUGH THIS FAR OUT...BUT CANNOT RULE OUT ANY ONE GIVEN PERIOD.
&&
.AVIATION...(12Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 605 AM CDT THU AUG 14 2014
A LITTLE PATCHY FOG IS POSSIBLE EARLY THIS MORNING...OTHERWISE
GENERALLY LOOK FOR VFR CONDITIONS THROUGH THE PERIOD. WE COULD
SEE SOME ISOLD TSRA AFTER 06Z TONIGHT. MVFR CONDITIONS WOULD BE
PSBL IF PCPN DEVELOPS.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
UPDATE...DEWALD
SHORT TERM...KERN
LONG TERM...KERN
AVIATION...MILLER
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
945 AM PDT THU AUG 14 2014
.SYNOPSIS...DRIER AIR ARRIVING FROM THE WEST WILL LIMIT THUNDERSTORM
CHANCES MAINLY TO MOHAVE COUNTY TODAY. DRY WEATHER WILL OCCUR
THROUGH THE WEEKEND AND INTO NEXT WEEK...WITH TEMPERATURES WARMING
TO NEAR NORMAL BY SATURDAY AND CLIMBING A FEW DEGREES ABOVE NORMAL
FOR NEXT WEEK.
&&
.UPDATE...MAY JUST BE ENOUGH MOISTURE/INSTABILITY THIS AFTERNOON FOR
A BRIEF SHOWER OR THUNDERSTORM OVER THE HIGHER TERRAIN OF FAR
SOUTHERN CLARK COUNTY. INCREASED POPS AROUND SEARCHLIGHT THIS
AFTERNOON.
OTHERWISE, HI RES MODELS AND HRRR SUGGEST BEST CONVECTIVE PARAMETERS
WILL BE ACROSS EASTERN LINCOLN COUNTY AND MOHAVE COUNTY TODAY.
MODELS STILL INDICATE AIR MASS WILL CONTINUE TO DAY/STABILIZE FROM
THE WEST FRIDAY AND BEYOND.
&&
.SHORT TERM /THROUGH SATURDAY NIGHT/...
THE SYNOPTIC PATTERN THIS MORNING FEATURES A CLOSED UPPER LOW OVER
THE PACIFIC NORTHWEST...RIDGING FROM TEXAS NORTHWARD INTO
CANADA...AND TROUGHING OVER THE EASTERN CONUS. THE UPPER LOW OVER
THE PACIFIC NORTHWEST WILL GRADUALLY SHIFT EAST THROUGH THE SHORT
TERM PERIOD. THIS WILL CONTINUE TO DISPLACE THE RIDGE FARTHER TO THE
SOUTH ALLOWING FOR DRY WEST-SOUTHWEST FLOW ALOFT TO REMAIN OVER OUR
AREA. THE DRYING TREND CONTINUES THIS MORNING FROM WEST TO EAST.
NEARLY ALL THE IPW SENSORS ARE SHOWING ROUGHLY A QUARTER TO SEVEN
TENTHS OF AN INCH OF MOISTURE LOSS OVER THE LAST 24 HOURS...AS OF
THIS WRITING.
THE DRYING WILL LIMIT ANY THUNDERSTORM THREAT TO MOHAVE COUNTY AND
PORTIONS OF FAR EASTERN LINCOLN COUNTY THIS AFTERNOON AND EARLY
EVENING. FOR FRIDAY AND SATURDAY...THE ENTIRE FORECAST AREA IS
LOOKING DRY. SHOULD SEE SOME CUMULUS CLOUDS OVER THE HIGHER TERRAIN
OF MOHAVE COUNTY BUT LACK OF DEEP MOISTURE AND ADEQUATE FORCING WILL
MEAN NO CHANCE OF RAIN. HIGH TEMPERATURES WILL WARM BACK CLOSER TO
NORMAL AS WE HEAD INTO THE WEEKEND AND SOUTHERLY BREEZES WILL BE
COMMON EACH AFTERNOON.
.LONG TERM...SUNDAY THROUGH THURSDAY...AN EXTENDED DRY PERIOD LOOKS
PROBABLE FOR THE ENTIRE REGION LASTING WELL INTO NEXT WEEK. FLAT
HIGH PRESSURE RIDGE WITH TROUGHING OFF THE COAST OF NORTHERN
CALIFORNIA WILL RESULT IN MONSOON MOISTURE SHUNTED SOUTHWARD WHILE A
DRY SOUTHWESTERLY FLOW IS ADVECTED INTO THE MOJAVE DESERT AND
SOUTHERN GREAT BASIN. THIS IS NOT A FAVORABLE PATTERN FOR OUR
MONSOON LOVERS OUT THERE...IN FACT WE WILL BE LUCKY TO EVEN SEE AN
ISOLATED STORM IN THE HIGHEST PEAKS OF MOHAVE COUNTY NEXT WEEK.
KEPT THE FORECAST DRY FOR THE ENTIRE REGION IN THE EXTENDED TIME
FRAME...HOWEVER, GIVEN THE TIME OF YEAR, WE WILL NEED TO WATCH THE
MARGINAL MOISTURE AROUND FOR THE POSSIBILITY OF ISOLATED ACTIVITY IN
MOHAVE COUNTY.
WITH THE DRY CONDITIONS FORECAST...TEMPERATURES WILL HAVE NO TROUBLE
CLIMBING ABOVE NORMAL AND I TRENDED THE TEMPERATURES UPWARDS FOR
NEXT WEEK...AND A FEW DEGREES ABOVE GUIDANCE. TEMPERATURES SUNDAY
ONWARD WILL AVERAGE 3 TO 5 DEGREES ABOVE THE SEASONAL AVERAGE.
&&
.AVIATION...FOR MCCARRAN...ENOUGH MOISTURE WILL REMAIN IN PLACE FOR
CUMULUS DEVELOPMENT OVER THE MOUNTAINS THIS AFTERNOON...BUT NOT
EXPECTING ENOUGH DEVELOPMENT FOR RAIN. SOUTHERLY WINDS THIS MORNING
ARE EXPECTED TO CONTINUE WITH SOME GUSTS TO AROUND 20-25 KNOTS THIS
AFTERNOON. GUSTS WILL DIMINISH...BUT SOUTHERLY WINDS WILL CONTINUE
OVERNIGHT AND INTO FRIDAY MORNING.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...SCATTERED CUMULUS ARE EXPECTED AGAIN TODAY WITH A
SLIGHT CHANCE OF THUNDERSTORMS OVER LINCOLN/MOHAVE COUNTIES. WINDS
WILL FAVOR TYPICAL DIURNAL WIND PATTERNS WITH GUSTS TO AROUND 20-25
KNOTS THIS AFTERNOON.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTER ACTIVATION IS NOT EXPECTED
THROUGH AT LEAST THE EARLY PART OF NEXT WEEK.
&&
$$
UPDATE...PIERCE
SHORT TERM/AVIATION...PADDOCK
LONG TERM...OUTLER
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS ELKO NV
356 AM PDT THU AUG 14 2014
.SYNOPSIS...THUNDERSTORMS WILL IMPACT NORTHEASTERN NEVADA INTO
THIS EVENING. DRIER AND MORE STABLE AIR BUILDING IN FROM THE
SOUTHWEST WILL RESULT IN STORM ACTIVITY ENDING ACROSS MOST OF THE
REGION TONIGHT. WARM AND DRY FRIDAY ON INTO NEXT WEEK.
&&
.SHORT TERM...TODAY THROUGH FRIDAY. NAM/EURO/GFS ALL AGREE VERY
WELL ON MAJOR AND MINOR FEATURES THROUGH THE SHORT TERM PERIOD.
UPPER LOW OVER PACIFIC NORTHWEST IS THE DRIVING FORCE BEHIND THE
CHANGE IN THE WEATHER COMING TO THE GREAT BASIN. DRY SOUTHWEST
FLOW WILL TAKE OVER SLOWLY STARTING TODAY AND CONTINUING INTO LATE
FRIDAY. EXITING SHORTWAVE WILL CAUSE LINGERING SHOWERS OVER
NORTHERN NEVADA WITH ISOLATED THUNDER OVER NORTHEAST NEVADA AND
JUST STRAY THUNDERSTORMS OVER EASTERN NEVADA TODAY AND THIS
EVENING. HRRR SHOWS AMPLE MOISTURE OVER EASTERN SECTIONS AND
THEREFORE SOME RISK OF LOCAL FLOODING STILL EXISTS THROUGH THE END
OF STORMS TONIGHT. HAIL MAY ALSO BE AN ISSUE...WITH LIMITED RISK
OF DAMAGING DOWNBURST WINDS. FOR LATE THURSDAY NIGHT INTO
FRIDAY...MODELS AGREE ON STORM FREE FOR THE ENTIRE FORECAST
AREA...THEREFORE POPS VERY LOW TO ZERO.
WINDS PICKS UP A BIT TODAY IN WHITE PINE COUNTY AND NORTHEAST NYE
COUNTY. GUSTING TO NEAR 30 MPH AT TIMES IN THE AFTERNOON TODAY. BB
.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY. GFS AND ECMWF IN
CLOSER AGREEMENT TONIGHT THROUGH THE LONG TERM. ON FRIDAY NIGHT A
TROUGH WILL BE LOCATED TO OUR NORTH WITH A CLOSED LOW SETTING UP
SHOP OVER THE EASTERN PACIFIC WEST OF CALIFORNIA. THIS WILL PLACE
A DRY WEST TO SOUTHWEST FLOW OVER OUR REGION. A LITTLE VORT
MAX/SHORTWAVE IS PROGGED TO MOVE ACROSS NORTHWEST NEVADA LATER
SATURDAY...AND ITS POSSIBLE THIS SYSTEM TRIGGERS A STRAY
THUNDERSTORM IN HUMBOLDT COUNTY...BUT OTHERWISE SATURDAY SHOULD BE
DRY. AFTER THAT...THE REGION WILL BE DOMINATED BY A DRY RIDGE
WEDGED IN BETWEEN THE CLOSED LOW TO THE WEST OF CALIFORNIA AND
FAST WESTERLY FLOW TO THE NORTH OVER THE FAR NORTHWESTERN U.S. AND
SOUTHERN CANADA. THERE COULD STILL BE AN ISOLATED DRY THUNDERSTORM
ONE OR MORE DAYS ALONG THE NORTHERN OR EASTERN PARTS OF THE CWA AS
MOISTURE LEVELS IN THESE AREAS WILL BE NEAR 0.5 INCH...BUT
GENERALLY THE ODDS ARE BELOW 15 PERCENT. TEMPERATURES WILL BE WARM
AND THINK GUIDANCE HAS BEEN RUNNING COOL SO GENERALLY BUMPED
NUMBERS UP FROM GUIDANCE. RCM
&&
.AVIATION...AMPLE LOW LEVEL MOISTURE FROM RAIN OVER THE PAST FEW
DAYS MAY CONTRIBUTE TO FOG DEVELOPMENT OVER THE NEXT FEW HOURS AT
KEKO AND KELY. CHANCE APPEARS LOW BUT NOT ZERO SO HAVE INCLUDED
VCFG IN TAF. OTHERWISE...DRIER AIR MOVING IN WILL PREVENT STORM
DEVELOPMENT TODAY WITH BREEZY BUT NOT WINDY AFTERNOON CONDITIONS
AND SOME CUMULUS DEVELOPING AS LOW LEVEL MOISTURE MIXES OUT. RCM
&&
.FIRE WEATHER...DRY SOUTHWEST FLOW WILL BEGIN TO PUSH STORMS EAST
TODAY. ISOLATED THUNDERSTORMS OVER ZONES 469/470 AND VERY SPOTTY
OVER 455 TODAY AND THIS EVENING. STARTING TONIGHT...DRIER AIR
MOVES IN AND FRIDAY AND THE WEEKEND LOOK DRY. THIS AFTERNOON OVER
455...WINDS PICK UP TO NEAR RFW CRITERIA BUT RH VALUES ARE WELL
HIGH ENOUGH TO AVOID RFW. OVER PORTIONS OF ZONES 467/468 RH VALUES
ARE LOW DOUBLE DIGITS TODAY...BUT WINDS ARE WEAK ENOUGH TO AVOID A
RFW THERE TOO. INCREASING DRYNESS FROM THE SOUTH OVER THE
WEEKEND...BUT WINDS TEND TO SOFTEN. BB
&&
.LKN WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
98/93/93/98
AREA FORECAST DISCUSSION
NWS RALEIGH NC
353 PM EDT THU AUG 14 2014 305
.SYNOPSIS...A DRY CYCLONIC FLOW ALOFT WILL PREVAIL OVER THE MID-
ATLANTIC AND CAROLINAS THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 230 PM THURSDAY...
OVERVIEW: CYCLONIC FLOW ALOFT WILL DOMINATE THE UPPER LEVEL PATTERN
ACROSS CENTRAL NC THROUGH TONIGHT...ON THE SOUTHERN PERIPHERY OF AN
UNSEASONABLY DEEP UPPER LEVEL LOW STALLED IN VICINITY OF THE LOWER
GREAT LAKES/SOUTHERN QUEBEC. 14Z WV IMAGERY AND RAP DATA INDICATED A
POTENT SHORTWAVE UPSTREAM OVER IL/IN THIS MORNING. THIS FEATURE IS
PROGGED TO TRACK SE THROUGH KY EARLY THIS AFTERNOON...THEN EASTWARD
THROUGH SOUTHERN WV INTO SOUTHERN VA BY 00Z. DPVA ASSOC/W THE WAVE
WILL RESULT IN WEAK HEIGHT/SLP FALLS OVER THE REGION...WITH LOW-
LEVEL FLOW GRADUALLY VEERING FROM N/NE THIS MORNING TO SW/WSW THIS
AFTERNOON. THE AIRMASS OVER CENTRAL NC THIS MORNING IS UNSEASONABLY
DRY (PWAT 0.71" PER 12Z GSO RAOB)...A RESULT OF MID-LEVEL SUBSIDENCE
AND LOW-LEVEL COLD ADVECTION IN THE WAKE OF THE COLD FRONTAL PASSAGE
EARLY YESTERDAY. SFC DEWPOINTS WERE IN THE UPPER 50S TO LOWER 60S AT
14Z...AND ARE EXPECTED TO FALL INTO THE UPPER 40S TO LOWER/MID 50S
VIA THIS AFTERNOON IN ASSOC/W DIURNAL HEATING/MIXING.
PRECIP/TEMPS: DIURNAL HEATING WILL BE INSUFFICIENT TO DESTABILIZE
THE ATMOSPHERE OVER CENTRAL NC THIS AFT/EVE GIVEN A VERY DRY
BOUNDARY LAYER AND LITTLE IF ANY MOISTURE ADVECTION/RECOVERY...EVEN
AS FLOW VEERS TO THE SW/WSW. AS A RESULT...THE POTENT SHORTWAVE
ENERGY TRACKING THROUGH SOUTHERN WV/VA LATE THIS AFT/EVE SHOULD
YIELD LITTLE MORE THAN SCATTERED UPPER LEVEL CLOUD COVER...THOUGH
ISOLD SHOWER ACTIVITY COULD BE POSSIBLE TO THE NORTH IN WV/VA.
EXPECT HIGHS BELOW NORMAL IN THE LOWER 80S NW TO MID/UPPER 80S SOUTH
AND SE OF THE TRIANGLE. LOWS TONIGHT SIMILAR TO LAST NIGHT ALBEIT A
LITTLE WARMER DUE TO AIRMASS MODIFICATION TODAY...IN THE LOWER 60S
EARLY FRI MORNING. -VINCENT
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 255 PM THURSDAY...
OVERVIEW: CYCLONIC FLOW ALOFT WILL PERSIST OVER THE EAST COAST STATES
FRI INTO FRI NIGHT...ON THE SOUTHERN PERIPHERY OF AN UNSEASONABLY DEEP
UPPER LEVEL LOW STALLED OUT OVER SOUTHERN QUEBEC. AS THE UPPER LEVEL
TROUGH AXIS SHIFTS CLOSER TO THE COAST...WESTERLY FLOW ALOFT WILL GIVE
WAY TO NW FLOW ALOFT OVER THE CAROLINAS. A SECONDARY COLD FRONT WILL
APPROACH CENTRAL NC FROM THE NORTH TONIGHT BEFORE STALLING OUT WEST-
EAST IN VICINITY OF THE VA/NC BORDER ON FRIDAY. HEIGHT RISES ALOFT WILL
RESULT IN WEAK PRESSURE RISES OVER THE REGION FRI AS THE STALLED UPPER
LEVEL LOW IN QUEBEC WOBBLES NORTHWARD...THOUGH EPISODIC DPVA ASSOC/W
POTENT SHORTWAVE ENERGY DIGGING SOUTHEAST FROM CANADA THROUGH THE OH
VALLEY INTO THE CAROLINAS IN NW FLOW ALOFT WILL ALLOW FOR TROUGHING AT
TIMES.
CONVECTION: THE SECONDARY FRONT WILL STALL OUT ALONG OR NEAR THE VA
BORDER ON FRIDAY AS LOW-LEVEL FLOW (I.E. 925 MB) VEERS TO THE SSW/SW
AND ALLOWS MOISTURE RETURN...ESP IN CENTRAL/EASTERN NC. THE
COMBINATION OF DIURNAL HEATING AND INCREASED BOUNDARY LAYER MOISTURE
SHOULD ALLOW MARGINAL DESTABILIZATION FRI AFT/EVE...WITH MLCAPE VALUES
AS HIGH AS 1000-1500 J/KG SOUTH AND EAST OF THE TRIANGLE AND UP TO 500
J/KG IN THE NW PIEDMONT ACCORDING TO THE NAM...THOUGH THE GFS IS
NOTABLY MORE STABLE AND CAPPED. GIVEN EPISODIC DPVA IN THE PRESENCE OF
SOME DEGREE OF MOISTURE RETURN AND DESTABILIZATION...WILL INTRODUCE A
SLIGHT CHANCE OF CONVECTION DURING THE LATE AFTERNOON AND EVENING
HOURS. IF FOCUSED DPVA OCCURS AROUND OR SHORTLY AFTER PEAK HEATING IN
THE PRESENCE OF `NAM-LIKE` THERMO PROFILES WHEN 0-6 KM SHEAR IS PROGGED
AT 35-45 KT...A CONDITIONAL POTENTIAL FOR AN ISOLD SEVERE STORM WOULD
BE PRESENT. SUFFICIENT UNCERTAINTY IS PRESENT TO PRECLUDE ANY MENTION
OF HAZARDOUS WEATHER AT THIS TIME.
TEMPS: EXPECT HIGHS FRIDAY SLIGHTLY BELOW NORMAL IN THE MID/UPPER
80S...WITH LOWS FRI NIGHT IN THE 60S. -VINCENT
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
AS OF 310 PM THURSDAY...
THE UPPER AIR PATTERN DURING THE LONG RANGE EVOLVES FROM A NORTHEAST
CONUS TROUGH AND A DESERT SOUTHWEST RIDGE OVER THE WEEKEND TO A FLATTER
AND MORE ZONAL PATTERN BY THE MIDDLE OF NEXT WEEK. THIS WILL RESULT IN
A WARMING OF TEMPERATURES WITH SMALL CHANCES OF PRECIPITATION MAINLY
DURING THE EARLY TO MID PORTION OF NEXT WEEK.
MODEL GUIDANCE IS IN GOOD AGREEMENT THAT THE NORTHWEST FLOW PRESENT AT
THE START OF THE PERIOD SATURDAY AND THE ASSOCIATED LEE TROUGHING WILL
DAMPEN BY LATE SUNDAY. THE NAM/GFS/ECMWF INDICATE THAT SOME SCATTERED
CONVECTIVE PRECIPITATION IS POSSIBLE IN THE COASTAL PLAIN OR COASTAL
REGION DURING THE AFTN/EVENING. AROUND A THIRD OF THE SREF MEMBERS AT
FAY/RWI/RDU INDICATE SOME LIGHT PRECIPITATION WITH THE PRECIPITATION
GENERATED BY THE ARW MEMBERS FOR THE MOST PART ACROSS THESE LOCATIONS.
MOS GUIDANCE POPS ARE LOW AND GENERALLY RANGE LESS THAN 15%. GIVEN
THIS...HAVE OPTED TO INSERT A NARROW CORRIDOR OF SLIGHT CHANCE POPS FOR
SAT AFTERNOON IN THE COASTAL PLAIN BUT WILL HOLD OFF GOING ANY MORE
BULLISH. A SIMILAR SETUP OCCURS ON SUNDAY BUT GIVEN THE MORE WESTERLY
FLOW AND LOW CONFIDENCE WILL KEEP SUNDAY DRY FOR NOW. HIGHS WILL RANGE
IN THE UPPER 80S NORTH TO LOWER 90S SOUTH ON SAT AND A DEGREE OR TWO
WARMER ON SUN WITH MORNING LOWS IN THE UPPER 60S TO LOWER 70S.
STILL A FAIR AMOUNT OF UNCERTAINTY WITH THE PATTERN FOR NEXT WEEK AS A
COLD FRONT DROPS INTO THE MID ATLANTIC STATES AND BECOMES STATIONARY AS
A WEAK SURFACE LOW DEVELOPS OVER THE WESTERN OH VALLEY AND SLOWLY MOVES
EAST. GFS/ECMWF GUIDANCE DIFFERS QUITE A BIT ON THE EVOLUTION AND
EASTWARD PROGRESSION OF THIS SYSTEM. LATEST GUIDANCE FROM HPC LEANS
TOWARD THE ECMWF AND THE EC ENSEMBLE WHICH HAS BEEN MORE STABLE AND TO
WHICH THE GFS IS TRENDING. THE RESULT WILL BE AN INCREASE IN THE THREAT
OF MAINLY DIURNALLY FORCED CONVECTION DURING THE UPCOMING WORK WEEK
WITH PERHAPS THE BEST COVERAGE ON MONDAY AND TUESDAY. THICKNESS VALUES
INCREASE A BIT THROUGH THE PERIOD...WITH THE 1000-850 MB THICKNESS
REACHING THE 1430S BY THURSDAY. THIS WIL RESULT IN AN INCREASE IN MAX
TEMPS TO NEAR OR JUST ABOVE AVERAGE WITH HIGHS IN THE UPPER 80S TO
LOWER 90S. INCREASING MOISTURE WILL RESULT IN OVERNIGHT LOWS MODERATING
INTO THE LOWER 70S BY MID WEEK. -BLAES
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 200 PM THURSDAY...
24-HR TAF PERIOD: HIGH CONFIDENCE IN VFR CONDITIONS AND LIGHT WINDS
THROUGH THE TAF PERIOD IN ASSOC/W A DRY AND STABLE AIRMASS OVER THE
REGION. A SMALL POTENTIAL FOR ISOLD CONVECTION CANNOT BE RULED OUT LATE
FRI AFTERNOON AND EVENING.
LOOKING AHEAD: VFR CONDITIONS WILL PREVAIL THROUGH THE WEEKEND...THOUGH
WITH AN INCREASING POTENTIAL FOR AFTERNOON AND EVENING CONVECTION LATE
THIS WEEKEND THROUGH EARLY NEXT WEEK. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM...VINCENT
LONG TERM...BLAES
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
310 PM EDT THU AUG 14 2014 305
.SYNOPSIS...A DRY CYCLONIC FLOW ALOFT WILL PREVAIL OVER THE MID-
ATLANTIC AND CAROLINAS THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH FRIDAY NIGHT/...
AS OF 1030 AM THURSDAY...
TODAY/TONIGHT OVERVIEW: CYCLONIC FLOW ALOFT WILL DOMINATE THE UPPER
LEVEL PATTERN ACROSS CENTRAL NC THROUGH TONIGHT...ON THE SOUTHERN
PERIPHERY OF AN UNSEASONABLY DEEP UPPER LEVEL LOW STALLED IN VICINITY
OF THE LOWER GREAT LAKES/SOUTHERN QUEBEC. 14Z WV IMAGERY AND RAP DATA
INDICATED A POTENT SHORTWAVE UPSTREAM OVER IL/IN THIS MORNING. THIS
FEATURE IS PROGGED TO TRACK SE THROUGH KY EARLY THIS AFTERNOON...THEN
EASTWARD THROUGH SOUTHERN WV INTO SOUTHERN VA BY 00Z. DPVA ASSOC/W THE
WAVE WILL RESULT IN WEAK HEIGHT/SLP FALLS OVER THE REGION...WITH LOW-
LEVEL FLOW GRADUALLY VEERING FROM N/NE THIS MORNING TO SW/WSW THIS
AFTERNOON. THE AIRMASS OVER CENTRAL NC THIS MORNING IS UNSEASONABLY DRY
(PWAT 0.71" PER 12Z GSO RAOB)...A RESULT OF MID-LEVEL SUBSIDENCE AND
LOW-LEVEL COLD ADVECTION IN THE WAKE OF THE COLD FRONTAL PASSAGE EARLY
YESTERDAY. SFC DEWPOINTS WERE IN THE UPPER 50S TO LOWER 60S AT
14Z...AND ARE EXPECTED TO FALL INTO THE UPPER 40S TO LOWER/MID 50S VIA
THIS AFTERNOON IN ASSOC/W DIURNAL HEATING/MIXING.
TODAY/TONIGHT FORECAST: DIURNAL HEATING WILL BE INSUFFICIENT TO
DESTABILIZE THE ATMOSPHERE OVER CENTRAL NC THIS AFT/EVE GIVEN A VERY
DRY BOUNDARY LAYER AND LITTLE IF ANY MOISTURE ADVECTION/RECOVERY...EVEN
AS FLOW VEERS TO THE SW/WSW. AS A RESULT...THE POTENT SHORTWAVE ENERGY
TRACKING THROUGH SOUTHERN WV/VA LATE THIS AFT/EVE SHOULD YIELD LITTLE
MORE THAN SCATTERED UPPER LEVEL CLOUD COVER. EXPECT HIGHS BELOW NORMAL
IN THE LOWER 80S NW TO MID/UPPER 80S SOUTH AND SE OF THE TRIANGLE. LOWS
TONIGHT SIMILAR TO LAST NIGHT ALBEIT A LITTLE WARMER DUE TO AIRMASS
MODIFICATION TODAY...IN THE LOWER 60S EARLY FRI MORNING. -VINCENT
FOR FRI/FRI NIGHT: THE AFOREMENTIONED E-W ORIENTED SECONDARY FRONT
LOOKS LIKELY TO STALL OUT JUST NORTH OF THE NC/VA BORDER FRI AS A
WEAK TROUGH FORMS OVER THE PIEDMONT. PW IS PREDICTED TO STEADILY
INCREASE LATE IN THE DAY THROUGH EVENING TO AT OR ABOVE 1.5" FROM
THE TRIANGLE EAST AND SE... ALONG AND AHEAD OF THE WEAK PIEDMONT
TROUGH. THE NAM/GFS BOTH SHOW WEAK LOW PRESSURE FORMING FRI EVENING
OVER THE NE PIEDMONT... AND THIS SUBTLE MASS CONVERGENCE JUST SOUTH
OF THE BACKDOOR FRONT COMBINED WITH INCREASING MOISTURE AND
IMPROVING (BUT STILL MODEST) INSTABILITY (MLCAPE RISING TO 500-1500
J/KG) IN THIS AREA MAY SUPPORT ISOLATED SHOWERS AND PERHAPS A STORM
OVER THE NORTHEAST QUARTER OF THE CWA. LOTS OF UNCERTAINTY HOWEVER
WITH A LACK OF MID-UPPER SUPPORT FOR POPS... SO WILL RAISE POPS TO
10-14% FOR NOW... AND CONTINUE TO MONITOR FOR POSSIBLE INCLUSION OF
A SLIGHT CHANCE OF SHOWERS/STORMS IN LATER FORECASTS. IN ANY CASE...
DO EXPECT AN INCREASE IN CLOUDS TO PARTLY CLOUDY LATE FRI THROUGH
FRI NIGHT... ESPECIALLY IN THE NE CWA. SHOULD SEE NEAR NORMAL HIGHS
OF 86-90... WITH LOWS INCHING BACK UP TOWARD NORMAL.. 63-68. -GIH
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 240 AM THURSDAY...
CENTRAL NC IS IN FOR A WARM AND DRY WEEKEND FOR A CHANGE AS A ZONAL
UPPER LEVEL PATTERN COINCIDES WITH RELATIVE HIGH PRESSURE AT THE
SURFACE ON THE BACK SIDE OF THE BERMUDA HIGH WHICH WILL USHER IN THE
RETURN FLOW RESPONSIBLE FOR THE WARMER TEMPERATURES. MODEL THICKNESS
VALUES SOAR AS HIGH AS THE 1420S ON THE MORE AGGRESSIVE GFS
SUGGESTING HIGHS IN THE LOWER 90S BUT SOME POSSIBLE SHORTWAVE
INDUCED CLOUDINESS COULD KEEPS TEMPERATURES DOWN A LITTLE AS
SUGGESTED BY ADJUSTED MOS GUIDANCE. WILL GO WITH UPPER 80S TO LOWER
90S NORTHWEST TO SOUTHEAST WITH SUNDAY BEING THE WARMER DAY OUT OF
THE TWO. LOWS IN THE MID 60S TO LOWER 70S. LIGHT WINDS OUT OF THE
SOUTH LESS THAN 5 KTS.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
AS OF 310 PM THURSDAY...
THE UPPER AIR PATTERN DURING THE LONG RANGE EVOLVES FROM A
NORTHEAST CONUS TROUGH AND A DESERT SOUTHWEST RIDGE OVER THE
WEEKEND TO A FLATTER AND MORE ZONAL PATTERN BY THE MIDDLE OF NEXT
WEEK. THIS WILL RESULT IN A WARMING OF TEMPERATURES WITH SMALL
CHANCES OF PRECIPITATION MAINLY DURING THE EARLY TO MID PORTION
OF NEXT WEEK.
MODEL GUIDANCE IS IN GOOD AGREEMENT THAT THE NORTHWEST FLOW PRESENT
AT THE START OF THE PERIOD SATURDAY AND THE ASSOCIATED LEE TROUGHING
WILL DAMPEN BY LATE SUNDAY. THE NAM/GFS/ECMWF INDICATE THAT SOME
SCATTERED CONVECTIVE PRECIPITATION IS POSSIBLE IN THE COASTAL PLAIN
OR COASTAL REGION DURING THE AFTN/EVENING. AROUND A THIRD OF THE SREF
MEMBERS AT FAY/RWI/RDU INDICATE SOME LIGHT PRECIPITATION WITH THE
PRECIPITATION GENERATED BY THE ARW MEMBERS FOR THE MOST PART ACROSS
THESE LOCATIONS. MOS GUIDANCE POPS ARE LOW AND GENERALLY RANGE LESS
THAN 15%. GIVEN THIS...HAVE OPTED TO INSERT A NARROW CORRIDOR OF
SLIGHT CHANCE POPS FOR SAT AFTERNOON IN THE COASTAL PLAIN BUT WILL
HOLD OFF GOING ANY MORE BULLISH. A SIMILAR SETUP OCCURS ON SUNDAY
BUT GIVEN THE MORE WESTERLY FLOW AND LOW CONFIDENCE WILL KEEP SUNDAY
DRY FOR NOW. HIGHS WILL RANGE IN THE UPPER 80S NORTH TO LOWER 90S
SOUTH ON SAT AND A DEGREE OR TWO WARMER ON SUN WITH MORNING LOWS IN
THE UPPER 60S TO LOWER 70S.
STILL A FAIR AMOUNT OF UNCERTAINTY WITH THE PATTERN FOR NEXT WEEK AS
A COLD FRONT DROPS INTO THE MID ATLANTIC STATES AND BECOMES STATIONARY
AS A WEAK SURFACE LOW DEVELOPS OVER THE WESTERN OH VALLEY AND SLOWLY
MOVES EAST. GFS/ECMWF GUIDANCE DIFFERS QUITE A BIT ON THE EVOLUTION
AND EASTWARD PROGRESSION OF THIS SYSTEM. LATEST GUIDANCE FROM HPC
LEANS TOWARD THE ECMWF AND THE EC ENSEMBLE WHICH HAS BEEN MORE STABLE
AND TO WHICH THE GFS IS TRENDING. THE RESULT WILL BE AN INCREASE IN
THE THREAT OF MAINLY DIURNALLY FORCED CONVECTION DURING THE UPCOMING
WORK WEEK WITH PERHAPS THE BEST COVERAGE ON MONDAY AND TUESDAY.
THICKNESS VALUES INCREASE A BIT THROUGH THE PERIOD...WITH THE 1000-850
MB THICKNESS REACHING THE 1430S BY THURSDAY. THIS WIL RESULT IN AN
INCREASE IN MAX TEMPS TO NEAR OR JUST ABOVE AVERAGE WITH HIGHS IN
THE UPPER 80S TO LOWER 90S. INCREASING MOISTURE WILL RESULT IN
OVERNIGHT LOWS MODERATING INTO THE LOWER 70S BY MID WEEK. -BLAES
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AS OF 645 AM THURSDAY...
HIGH CONFIDENCE IN FAVORABLE VFR CONDITIONS TODAY THROUGH TONIGHT.
HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE REGION FROM THE
WEST... RESULTING IN LIGHT SURFACE WINDS GENERALLY UNDER 8 KTS...
MAINLY FROM THE NW OR NORTH TODAY. ANY CLOUDS WILL BE MOST NUMEROUS
IN THE LATE AFTERNOON THROUGH TONIGHT WITH ANY BASES ABOVE 4000 FT
AGL. VERY LIGHT WINDS WILL BECOME MAINLY SOUTHWESTERLY TONIGHT AS A
WEAK SECONDARY BACKDOOR FRONT APPROACHES FROM THE NORTH LATE.
LOOKING BEYOND 12Z FRI MORNING... VFR CONDITIONS LIKELY TO DOMINATE
THROUGH AT LEAST SUNDAY NIGHT WITH DRY AIR IN PLACE. A POTENTIAL
STORM SYSTEM MAY APPROACH FROM THE WEST MONDAY... BRINGING A CHANCE
OF SUB-VFR CONDITIONS AND SHOWERS/STORMS. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT/HARTFIELD
SHORT TERM...ELLIS
LONG TERM...BLAES
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1035 AM EDT THU AUG 14 2014
.SYNOPSIS...A DRY CYCLONIC FLOW ALOFT WILL PREVAIL OVER THE MID-
ATLANTIC AND CAROLINAS THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH FRIDAY NIGHT/...
AS OF 1030 AM THURSDAY...
TODAY/TONIGHT OVERVIEW: CYCLONIC FLOW ALOFT WILL DOMINATE THE UPPER
LEVEL PATTERN ACROSS CENTRAL NC THROUGH TONIGHT...ON THE SOUTHERN
PERIPHERY OF AN UNSEASONABLY DEEP UPPER LEVEL LOW STALLED IN VICINITY
OF THE LOWER GREAT LAKES/SOUTHERN QUEBEC. 14Z WV IMAGERY AND RAP DATA
INDICATED A POTENT SHORTWAVE UPSTREAM OVER IL/IN THIS MORNING. THIS
FEATURE IS PROGGED TO TRACK SE THROUGH KY EARLY THIS AFTERNOON...THEN
EASTWARD THROUGH SOUTHERN WV INTO SOUTHERN VA BY 00Z. DPVA ASSOC/W THE
WAVE WILL RESULT IN WEAK HEIGHT/SLP FALLS OVER THE REGION...WITH LOW-
LEVEL FLOW GRADUALLY VEERING FROM N/NE THIS MORNING TO SW/WSW THIS
AFTERNOON. THE AIRMASS OVER CENTRAL NC THIS MORNING IS UNSEASONABLY DRY
(PWAT 0.71" PER 12Z GSO RAOB)...A RESULT OF MID-LEVEL SUBSIDENCE AND
LOW-LEVEL COLD ADVECTION IN THE WAKE OF THE COLD FRONTAL PASSAGE EARLY
YESTERDAY. SFC DEWPOINTS WERE IN THE UPPER 50S TO LOWER 60S AT
14Z...AND ARE EXPECTED TO FALL INTO THE UPPER 40S TO LOWER/MID 50S VIA
THIS AFTERNOON IN ASSOC/W DIURNAL HEATING/MIXING.
TODAY/TONIGHT FORECAST: DIURNAL HEATING WILL BE INSUFFICIENT TO
DESTABILIZE THE ATMOSPHERE OVER CENTRAL NC THIS AFT/EVE GIVEN A VERY
DRY BOUNDARY LAYER AND LITTLE IF ANY MOISTURE ADVECTION/RECOVERY...EVEN
AS FLOW VEERS TO THE SW/WSW. AS A RESULT...THE POTENT SHORTWAVE ENERGY
TRACKING THROUGH SOUTHERN WV/VA LATE THIS AFT/EVE SHOULD YIELD LITTLE
MORE THAN SCATTERED UPPER LEVEL CLOUD COVER. EXPECT HIGHS BELOW NORMAL
IN THE LOWER 80S NW TO MID/UPPER 80S SOUTH AND SE OF THE TRIANGLE. LOWS
TONIGHT SIMILAR TO LAST NIGHT ALBEIT A LITTLE WARMER DUE TO AIRMASS
MODIFICATION TODAY...IN THE LOWER 60S EARLY FRI MORNING. -VINCENT
FOR FRI/FRI NIGHT: THE AFOREMENTIONED E-W ORIENTED SECONDARY FRONT
LOOKS LIKELY TO STALL OUT JUST NORTH OF THE NC/VA BORDER FRI AS A
WEAK TROUGH FORMS OVER THE PIEDMONT. PW IS PREDICTED TO STEADILY
INCREASE LATE IN THE DAY THROUGH EVENING TO AT OR ABOVE 1.5" FROM
THE TRIANGLE EAST AND SE... ALONG AND AHEAD OF THE WEAK PIEDMONT
TROUGH. THE NAM/GFS BOTH SHOW WEAK LOW PRESSURE FORMING FRI EVENING
OVER THE NE PIEDMONT... AND THIS SUBTLE MASS CONVERGENCE JUST SOUTH
OF THE BACKDOOR FRONT COMBINED WITH INCREASING MOISTURE AND
IMPROVING (BUT STILL MODEST) INSTABILITY (MLCAPE RISING TO 500-1500
J/KG) IN THIS AREA MAY SUPPORT ISOLATED SHOWERS AND PERHAPS A STORM
OVER THE NORTHEAST QUARTER OF THE CWA. LOTS OF UNCERTAINTY HOWEVER
WITH A LACK OF MID-UPPER SUPPORT FOR POPS... SO WILL RAISE POPS TO
10-14% FOR NOW... AND CONTINUE TO MONITOR FOR POSSIBLE INCLUSION OF
A SLIGHT CHANCE OF SHOWERS/STORMS IN LATER FORECASTS. IN ANY CASE...
DO EXPECT AN INCREASE IN CLOUDS TO PARTLY CLOUDY LATE FRI THROUGH
FRI NIGHT... ESPECIALLY IN THE NE CWA. SHOULD SEE NEAR NORMAL HIGHS
OF 86-90... WITH LOWS INCHING BACK UP TOWARD NORMAL.. 63-68. -GIH
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 240 AM THURSDAY...
CENTRAL NC IS IN FOR A WARM AND DRY WEEKEND FOR A CHANGE AS A ZONAL
UPPER LEVEL PATTERN COINCIDES WITH RELATIVE HIGH PRESSURE AT THE
SURFACE ON THE BACK SIDE OF THE BERMUDA HIGH WHICH WILL USHER IN THE
RETURN FLOW RESPONSIBLE FOR THE WARMER TEMPERATURES. MODEL THICKNESS
VALUES SOAR AS HIGH AS THE 1420S ON THE MORE AGGRESSIVE GFS
SUGGESTING HIGHS IN THE LOWER 90S BUT SOME POSSIBLE SHORTWAVE
INDUCED CLOUDINESS COULD KEEPS TEMPERATURES DOWN A LITTLE AS
SUGGESTED BY ADJUSTED MOS GUIDANCE. WILL GO WITH UPPER 80S TO LOWER
90S NORTHWEST TO SOUTHEAST WITH SUNDAY BEING THE WARMER DAY OUT OF
THE TWO. LOWS IN THE MID 60S TO LOWER 70S. LIGHT WINDS OUT OF THE
SOUTH LESS THAN 5 KTS.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 240 AM THURSDAY...
THE PATTERN STARTS TO BECOME A LITTLE MORE ACTIVE ON MONDAY AS A
WEAK SURFACE LOW MOVES THROUGH THE OHIO VALLEY AND INTO THE MID
ATLANTIC STATES. THE GFS IS MORE AGGRESSIVE WITH THE DEVELOPMENT AND
THE VERTICAL EXTENT OF THE LOW...INFLUENCING THE DEEPENING OF A
SHORTWAVE TROUGH AT 500 MB. THIS IS NOT SEEN ON THE 12Z RUN OF THE
ECMWF UNTIL LATER IN THE PERIOD. THE UPSHOT IS THE SAME...WHICH WILL
BE DIURNALLY DRIVEN PRECIPIATION CHANCES EACH AFTERNOON MONDAY
THROUGH WEDNESDAY WITH SLIGHT CHANCES DURING THE LESS FAVORABLE
NOCTURNAL HOURS. INSTABILITY WILL BE MODEST...UP TO 1000 J/KG AND
BULK SHEAR WILL GENERALLY STAY BETWEEN 10-20 KTS SUGGESTIVE OF
NOTHING MORE THAN GARDEN VARIETY SUMMERTIME THUNDERSHOWERS. ALTHOUGH
THICKNESSES GO UP...AN EXPECTED INCREASE IN CLOUD COVER AND
PRECIPITATION COVERAGE WILL KEEP HIGHS GENERALLY IN THE LOWER 90S
EACH DAY WITH LOWS OVERNIGHT IN THE UPPER 60S TO LOW 70S.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AS OF 645 AM THURSDAY...
HIGH CONFIDENCE IN FAVORABLE VFR CONDITIONS TODAY THROUGH TONIGHT.
HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE REGION FROM THE
WEST... RESULTING IN LIGHT SURFACE WINDS GENERALLY UNDER 8 KTS...
MAINLY FROM THE NW OR NORTH TODAY. ANY CLOUDS WILL BE MOST NUMEROUS
IN THE LATE AFTERNOON THROUGH TONIGHT WITH ANY BASES ABOVE 4000 FT
AGL. VERY LIGHT WINDS WILL BECOME MAINLY SOUTHWESTERLY TONIGHT AS A
WEAK SECONDARY BACKDOOR FRONT APPROACHES FROM THE NORTH LATE.
LOOKING BEYOND 12Z FRI MORNING... VFR CONDITIONS LIKELY TO DOMINATE
THROUGH AT LEAST SUNDAY NIGHT WITH DRY AIR IN PLACE. A POTENTIAL
STORM SYSTEM MAY APPROACH FROM THE WEST MONDAY... BRINGING A CHANCE
OF SUB-VFR CONDITIONS AND SHOWERS/STORMS. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT/HARTFIELD
SHORT TERM...ELLIS
LONG TERM...ELLIS
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
954 PM CDT FRI AUG 15 2014
.UPDATE...
ISSUED AT 954 PM CDT FRI AUG 15 2014
AN UPPER LEVEL MESO-LOW CONTINUES TO GENERATE MODERATE RAINFALL
ACROSS WEST-CENTRAL NORTH DAKOTA. RAINFALL AMOUNTS UNDER THE
HIGHEST REFLECTIVITIES HAVE TOTALED GENERALLY BETWEEN 1 AND 2
INCHES NEAR GRASSY BUTTE AND FAIRFIELD. OUTFLOW FROM
THUNDERSTORMS OVER NORTHEASTERN MONTANA IS RACING SOUTHEASTWARD
TOWARDS THIS AREA OF PERSISTENT RAIN SHOWERS...AND WILL LIKELY
ENHANCE LIFT AND RAINFALL INTENSITY DURING THE NEXT FEW HOURS. AS
A RESULT...WILL MAINTAIN THE FLASH FLOOD WATCH FOR THIS UPDATE.
FOCUS THEN SHIFTS UPSTREAM WHERE A LARGER SHORTWAVE IS GENERATING
A LINE OF THUNDERSTORMS ACROSS CENTRAL MONTANA. BASED ON ITS
CURRENT TRAJECTORY...THESE THUNDERSTORMS SHOULD CROSS INTO EXTREME
WESTERN NORTH DAKOTA AROUND 10Z. ALTHOUGH IT IS FORECAST TO BRING
ADDITIONAL RAINFALL WEST...IT SHOULD KICK THE MESO-LOW OUT OF
WEST-CENTRAL NORTH DAKOTA INTO SOUTH DAKOTA.
UPDATED THE SENSIBLE WEATHER ELEMENTS BASED ON CURRENT OBS/TRENDS.
THE UPDATED PRODUCTS WILL BE OUT SHORTLY.
UPDATE ISSUED AT 556 PM CDT FRI AUG 15 2014
THE LATEST MODEL GUIDANCE CONTINUES TO PROG THE HEAVY RAIN
POTENTIAL CONTINUING OVER SOUTHWESTERN NORTH DAKOTA TONIGHT. MOST
MODELS ARE A LITTLE TOO FAR SOUTH WITH THE ONGOING ACTIVITY...WITH
THE 12Z GEM ACTUALLY DOING A PRETTY GOOD JOB PAINTING THE HIGHEST
QPF WHERE THE CURRENT CONVECTION IS LOCATED.
FOR THE UPDATE...ADJUSTED POPS UPWARDS BASED ON CURRENT RADAR OBS
AND EXTRAPOLATED THE HIGHER POPS SOUTHEASTWARD THROUGH THE
OVERNIGHT HOURS...BASED ON THE 12Z GEM SOLUTION. WILL KEEP THE
CURRENT FLASH FLOOD WATCH AS IS FOR THIS UPDATE.
ALSO EXTENDED THE FLOOD ADVISORY FOR BILLINGS...SOUTHWESTERN
MCKENZIE...AND GOLDEN VALLEY COUNTIES UNTIL 530 AM CDT. THE LATEST
RAINFALL REPORT FROM BEACH IS 4.6 INCHES...AND IT IS STILL
RAINING. OVERLAND FLOODING CONTINUES TO BE AN ISSUE WITH SOME
COUNTY ROADS UNDER WATER.
THE UPDATED GRIDDED AND TEXT PRODUCTS WILL BE OUT SHORTLY.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 549 PM CDT FRI AUG 15 2014
HEAVY RAINFALL AND ASSOCIATED FLASH FLOODING WILL HIGHLIGHT THE
SHORT TERM FORECAST.
EXTENDED THE FLASH FLOOD WATCH THROUGH 12 UTC SATURDAY ACROSS THE
SOUTHWEST. THE 12 UTC WRF-ARW/NMM...INCOMING 18 UTC NAM AND 16-17
UTC HRRR ITERATIONS CONTINUE TO FOCUS RAIN SHOWERS AND
THUNDERSTORMS WITH PROLONGED MODERATE TO HEAVY RAINFALL ACROSS THE
SOUTHWEST AND FAR SOUTH CENTRAL LATE THIS AFTERNOON AND INTO THE
EARLY EVENING IN ASSOCIATION WITH THE UPPER LEVEL LOW EVIDENT ON
WATER VAPOR ACROSS THE SOUTHWEST. THESE SOLUTIONS WANE CONVECTION
A BIT AFTER SUNSET...THEN REDEVELOP THUNDERSTORMS ACROSS THE WEST
REINVIGORATED BY INCREASING UPPER LEVEL DIFFLUENCE AND IMPULSES
EJECTING OUT OF THE PACIFIC NORTHWEST CLOSED LOW. THIS IS IN
AGREEMENT WITH NESDIS SATELLITE PRECIPITATION ESTIMATES AND
HIGHLIGHTS FOR HEAVY RAINFALL TONIGHT. GIVEN THIS REGENERATION OF
SLOW MOVING STORMS LATE TONIGHT OVER ALREADY SATURATED AREAS WITH
PWATS NEAR 1.75 INCHES...THE EXTENSION OF THE WATCH IS WARRANTIED.
THE 12 UTC WRF-ARW/NMM DO HIGHLIGHT SIOUX AND EMMONS COUNTIES LATE
TONIGHT AS WELL FOR HEAVY RAIN...AND THIS WILL HAVE TO BE
MONITORED. ADDITIONAL SCATTERED THUNDERSTORMS WITH HEAVY RAIN WILL
CONTINUE ACROSS MUCH OF THE AREA SATURDAY AS THE PACIFIC NORTHWEST
UPPER LEVEL LOW BEGINS TO PROPAGATE INTO THE NORTHERN PLAINS. WILL
ALLOW FURTHER SHIFTS TO EVALUATE IF A FLASH FLOOD WATCH IS NEEDED.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 549 PM CDT FRI AUG 15 2014
THE MAIN FORECAST ISSUE IN THE EXTENDED PERIOD WILL CONTINUE TO BE
THE THREAT OF HEAVY RAINFALL THROUGH THE WEEKEND AND INTO EARLY NEXT
WEEK. DETERMINISTIC MODELS ARE IN REASONABLE AGREEMENT IN BRINGING
AN UPPER LEVEL LOW CURRENTLY OVER EASTERN WASHINGTON...EAST ALONG
THE INTERNATIONAL BORDER...TO THE EASTERN DAKOTAS BY MONDAY
AFTERNOON. ALTHOUGH THE THREAT OF SEVERE WEATHER WILL BE LOW. WE
WILL STILL NEED TO MONITOR THE THREAT OF HEAVY RAINFALL...
PARTICULARLY IN THE SUNDAY NIGHT INTO EARLY MONDAY PERIOD.
PERHAPS A BRIEF DRY PERIOD TUESDAY INTO EARLY WEDNESDAY. BUT MODELS
THEN START SHIFTING INTO MORE OF A SOUTHWEST FLOW BY MID TO LATE
WEEK BRINGING INCREASED PRECIPITATION CHANCES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 556 PM CDT FRI AUG 15 2014
THUNDERSTORM POTENTIAL WILL HIGHLIGHT THE 00 UTC TAF CYCLE.
KDIK/KBIS/KISN HAVE THE BEST POTENTIAL TO BE IMPACTED BY STORMS
WITH POSSIBLE IFR CONDITIONS. SEE TAFS FOR EXPECTED TIMING AND
IMPACTS.
&&
.HYDROLOGY...
ISSUED AT 954 PM CDT FRI AUG 15 2014
OVERLAND FLOODING WITH A FEW COUNTY ROADWAYS UNDER
WATER CONTINUE TO BE THE MAIN IMPACT FOR WEST-CENTRAL NORTH
DAKOTA...PRIMARILY ACROSS NORTHERN GOLDEN VALLEY COUNTY. SOILS ARE
SO SATURATED THAT GOLDEN VALLEY EMERGENCY MANAGEMENT CLOSED COUNTY
ROADS TO VEHICLES WEIGHING OVER 16,000 POUNDS. WILL CONTINUE WITH
THE AREAL FLOOD ADVISORIES AS A RESULT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 7 AM CDT /6 AM MDT/ SATURDAY FOR NDZ017-
018-031>033-040-041-043-044.
&&
$$
UPDATE...TM
SHORT TERM...AYD
LONG TERM...TWH
AVIATION...TM
HYDROLOGY...TM
AREA FORECAST DISCUSSION
NWS NORMAN OK
1055 PM CDT FRI AUG 15 2014
.AVIATION...
16/06Z TAFS...DISSIPATING SHOWERS MOVING THROUGH SW OK/ N TX
MAY AFFECT SWRN SITES EARLY IN THE PD...ALTHOUGH STILL EXPECT
CONDITIONS TO REMAIN VFR. WEAK FRONT WILL SHIFT WINDS TO THE N/NE
AT NRN OK SITES SAT. OTRW...VFR CONDITIONS WILL PREVAIL THROUGH THE
PD.
&&
.PREV DISCUSSION... /ISSUED 610 PM CDT FRI AUG 15 2014/
.AVIATION...
16/00Z TAFS...TSRA WILL AFFECT NW OK SITES EARLY IN THE PD
BUT THESE SHOULD DISSIPATE BY MID EVENING. OTRW...VFR CONDITIONS
EXPECTED TO PREVAIL THROUGH THE PD WITH SOME MID/HIGH CLOUD CIGS.
&&
.PREV DISCUSSION... /ISSUED 244 PM CDT FRI AUG 15 2014/
.DISCUSSION...
LATE TODAY THROUGH TONIGHT...A 500 MB SHORT WAVE
ACROSS THE CENTRAL PLAINS WILL TRANSLATE TO THE EAST INTO THE
MIDWEST. THIS WILL RESULT IN THE 500 MB RIDGE TO RETROGRADE
SLIGHTLY TO THE WEST. A DIFFUSE FRONTAL BOUNDARY WILL APPROACH
NORTHWEST OKLAHOMA LATER TODAY. BOTH THE NAM AND HRRR SUGGEST
ISOLATED SHOWERS AND STORMS MAY DEVELOP ALONG OR AHEAD OF THE
BOUNDARY LATE TODAY INTO THIS EVENING...BUT COVERAGE APPEARS TO BE
LIMITED. BEST CHANCES WILL BE ACROSS THE NORTHWEST. LARGE DEW
POINT DEPRESSIONS SUGGEST GUSTY WINDS WILL BE THE MAIN THREAT FROM
ANY STORMS THAT DO DEVELOP. HRRR ALSO SUGGESTS A COMPLEX MAY MOVE
THROUGH THE TEXAS PANHANDLE. THIS MAY CLIP EXTREME WESTERN AND
SOUTHWESTERN PARTS OF THE CWA.
ON SATURDAY...THE BOUNDARY WILL LIKELY BE VERY DIFFUSE. ISOLATED
STORMS WILL BE POSSIBLE ACROSS THE AREA. THE BIGGER STORY WILL BE
TEMPERATURES. 850MB TEMPERATURES ARE PROGGED TO BE BETWEEN 25 TO 28C
ACROSS THE CWA. AS A RESULT...SATURDAY MIGHT BE THE HOTTEST DAY IN
FORECAST THE PERIOD. MANY AREAS WILL SEE AT LEAST 100 DEGREE HEAT.
BEYOND SATURDAY...THE CWA APPEARS TO BE WITHIN A WEAKNESS IN THE
RIDGE. ISOLATED THUNDERSTORMS CAN NOT BE RULED OUT ALMOST ANY DAY
THROUGH AT LEAST MID-WEEK. TEMPERATURES LOOK TO BE SEASONABLY
HOT...THOUGH NOT AS HOT AS SATURDAY. THE RIDGE MAY TRY TO BUILD INTO
THE REGION BY LATE NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 74 99 74 98 / 10 20 20 20
HOBART OK 73 100 73 98 / 10 20 20 20
WICHITA FALLS TX 76 99 77 98 / 10 20 20 20
GAGE OK 68 101 69 98 / 20 20 20 20
PONCA CITY OK 74 98 72 98 / 20 20 20 20
DURANT OK 73 97 76 96 / 10 20 20 20
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
30/10/84
AREA FORECAST DISCUSSION
NWS NORMAN OK
610 PM CDT FRI AUG 15 2014
.AVIATION...
16/00Z TAFS...TSRA WILL AFFECT NW OK SITES EARLY IN THE PD
BUT THESE SHOULD DISSIPATE BY MID EVENING. OTRW...VFR CONDITIONS
EXPECTED TO PREVAIL THROUGH THE PD WITH SOME MID/HIGH CLOUD CIGS.
&&
.PREV DISCUSSION... /ISSUED 244 PM CDT FRI AUG 15 2014/
.DISCUSSION...
LATE TODAY THROUGH TONIGHT...A 500 MB SHORT WAVE
ACROSS THE CENTRAL PLAINS WILL TRANSLATE TO THE EAST INTO THE
MIDWEST. THIS WILL RESULT IN THE 500 MB RIDGE TO RETROGRADE
SLIGHTLY TO THE WEST. A DIFFUSE FRONTAL BOUNDARY WILL APPROACH
NORTHWEST OKLAHOMA LATER TODAY. BOTH THE NAM AND HRRR SUGGEST
ISOLATED SHOWERS AND STORMS MAY DEVELOP ALONG OR AHEAD OF THE
BOUNDARY LATE TODAY INTO THIS EVENING...BUT COVERAGE APPEARS TO BE
LIMITED. BEST CHANCES WILL BE ACROSS THE NORTHWEST. LARGE DEW
POINT DEPRESSIONS SUGGEST GUSTY WINDS WILL BE THE MAIN THREAT FROM
ANY STORMS THAT DO DEVELOP. HRRR ALSO SUGGESTS A COMPLEX MAY MOVE
THROUGH THE TEXAS PANHANDLE. THIS MAY CLIP EXTREME WESTERN AND
SOUTHWESTERN PARTS OF THE CWA.
ON SATURDAY...THE BOUNDARY WILL LIKELY BE VERY DIFFUSE. ISOLATED
STORMS WILL BE POSSIBLE ACROSS THE AREA. THE BIGGER STORY WILL BE
TEMPERATURES. 850MB TEMPERATURES ARE PROGGED TO BE BETWEEN 25 TO 28C
ACROSS THE CWA. AS A RESULT...SATURDAY MIGHT BE THE HOTTEST DAY IN
FORECAST THE PERIOD. MANY AREAS WILL SEE AT LEAST 100 DEGREE HEAT.
BEYOND SATURDAY...THE CWA APPEARS TO BE WITHIN A WEAKNESS IN THE
RIDGE. ISOLATED THUNDERSTORMS CAN NOT BE RULED OUT ALMOST ANY DAY
THROUGH AT LEAST MID-WEEK. TEMPERATURES LOOK TO BE SEASONABLY
HOT...THOUGH NOT AS HOT AS SATURDAY. THE RIDGE MAY TRY TO BUILD INTO
THE REGION BY LATE NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 74 99 74 98 / 10 20 20 20
HOBART OK 73 100 73 98 / 10 20 20 20
WICHITA FALLS TX 76 99 77 98 / 10 20 20 20
GAGE OK 68 101 69 98 / 20 20 20 20
PONCA CITY OK 74 98 72 98 / 20 20 20 20
DURANT OK 73 97 76 96 / 10 20 20 20
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
30/10/84
AREA FORECAST DISCUSSION
NWS MEDFORD OR
250 PM PDT THU AUG 14 2014
.DISCUSSION...CURRENT WATER VAPOR IMAGE SHOWS THE UPPER LOW CENTERED
ALONG THE OREGON/WASHINGTON BORDER. THERE`S PLENTY OF CLOUD COVER
OVER THE REGION, BUT SO FAR HAVE NOT SEEN ANY REPORTS OF MEASURABLE
PRECIPITATION. THE NAM AND THE GFS SHOW QPF BREAKING OUT EAST OF THE
CASCADES AND THE NAM SHOWS SOME IN NORTHERN CAL FROM THE SHASTA
TRINITY NORTHEAST TOWARDS LAKEVIEW. THE HRRR RADAR REFLECTIVITY WAS
ALSO SHOWING SPOTTY PRECIPITATION IN THE ABOVE MENTIONED AREAS
EARLIER THIS AFTERNOON, BUT IT HAS NOT VERIFIED. SO I HAVE LOW
CONFIDENCE IN THAT SOLUTION. BOTTOM LINE IS I DOUBT MUCH IF ANYTHING
WILL HAPPEN THIS FAR SOUTH FOR A FEW REASONS. FIRST, THE MODELS ARE
SHOWING SLIGHT WARMING ALOFT. SECOND, THE STRONGEST TRIGGER AND
COOLER AIR ALOFT WILL BE OVER THE NORTHEAST PART OF THE REGION.
THIRD, THE POSITION OF THE LOW IS NOT ONE THAT IS FAVORABLE FOR AN
OUTBREAK OF PRECIPITATION AND FINALLY THE MODEL SOUNDINGS SHOW A SUB
DRY LAYER, SO IF ANYTHING DEVELOPS, MOST WILL NOT REACH THE GROUND.
WITH THAT SAID, I COULD NOT RULE OUT A FEW LIGHT SHOWERS, BUT
PROBABLY NOT ANYTHING MEASURABLE. FURTHER NORTH IN NORTHERN LAKE AND
KLAMATH COUNTIES, EXPECT A FEW ISOLATED STORMS TO DEVELOP LATE THIS
AFTERNOON AND EARLY EVENING, THEN ENDING SHORTLY AFTER DARK.
THE UPPER LOW WILL CONTINUE TO SLOWLY MOVE NORTHEAST TONIGHT AND
CLOUD COVER WILL GRADUALLY DECREASE OVER MOST INLAND LOCATIONS.
TEMPERATURES EAST OF THE CASCADES WILL COOL DOWN INTO THE UPPER 30S
IN THE COOLER SPOTS IN NORTHERN KLAMATH COUNTY.
DRY AND MILDER WEATHER RETURNS FRIDAY AS THE UPPER LOW CONTINUE TO
SLOWLY MOVE NORTHEAST AND WEAK RIDGING BUILDS IN. TEMPERATURES WILL
REBOUND TO NEAR NORMAL VALUES ACROSS THE BOARD.
THIS RIDGING WILL BE SHORT LIVED. THE MODELS ARE ALL IN FAIRLY GOOD
AGREEMENT SHOWING ANOTHER, WEAK POSITIVE TILTED UPPER TROUGH
DEVELOPING OFF THE OREGON COAST SATURDAY AND REMAINING THERE THROUGH
SUNDAY WITH WEAK SHORTWAVES MOVING FROM SOUTHWEST TO NORTHEAST OVER
THE AREA. RIGHT NOW IT DOES NOT LOOK UNSTABLE ENOUGH FOR STORMS TO
DEVELOP SATURDAY. THE GFS DOES SHOW MID LEVEL MOISTURE INCREASING IN
THE AFTERNOON, BUT NOT ENOUGH TO BE A CONCERN, ESPECIALLY WITH
LITTLE OR NO TRIGGER. SUNDAY IS A DIFFERENT STORY. THE NAM SHOWS MID
LEVEL MOISTURE INCREASING OVER THE CASCADES AND WESTERN SISKIYOU
COUNTY IN THE AFTERNOON WITH NEGATIVE LI`S, INCREASING CAPE AND
STRONGER TRIGGER. THE GFS SHOWS A SIMILAR SOLUTION, BUT IS WEAKER
WITH THE AFOREMENTIONED PARAMETERS. DESPITE THIS, FELT IS BEST TO
INTRODUCE A SLIGHT CHANCE OF THUNDERSTORMS FOR THOSE AREAS SUNDAY
AFTERNOON AND EVENING.
THE UPPER TROUGH WILL TRANSITION TO AN UPPER LOW MONDAY WITH
MULTIPLE SHORTWAVE MOVING THROUGH AND INSTABILITY INCREASING ENOUGH
TO KEEP A SLIGHT MENTION OF STORMS FOR THE CASCADES AND SISKIYOUS.
THE MODELS SHOW A NORTHERN BRANCH OF THE JET BECOMING A BIGGER PLAY
MAKER FROM TUESDAY INTO THE END OF THE NEXT WEEK. THIS WILL PUSH THE
UPPER LOW SOUTH TUESDAY, THUS KEEPING ANY THREAT OF STORMS SOUTH OF
THE FORECAST AREA. THE UPPER TROUGH WILL AMPLIFY WEDNESDAY INTO
THE END OF THE WEEK. THIS WILL KEEP US DRY WITH NEAR NORMAL
TEMPERATURES. -PETRUCELLI
&&
.AVIATION...BASED ON THE 14/18Z TAF CYCLE...
EXPECT MVFR CIGS ALONG THE COAST NORTH OF CAPE BLANCO THIS
AFTERNOON, BUT IFR TO LIFR CIGS REDEVELOP THIS EVENING AND
OVERNIGHT. INLAND, VFR WILL PREVAIL BUT WITH TERRAIN OBSCURED IN
SOME AREAS THIS AFTERNOON. SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS ARE EXPECTED FROM ABOUT HIGHWAY 140 NORTH AND EASTWARD
THROUGH THIS EVENING. VFR IS EXPECT TONIGHT, THOUGH MVFR CIGS WILL
PROBABLY DEVELOP IN THE UMPQUA VALLEY AND LAST THROUGH MID TO LATE
MORNING FRIDAY. SPILDE
&&
.MARINE...UPDATED 230 PM PDT WED 14 AUG 2014...
THE WATERS WILL REMAIN BETWEEN HIGH PRESSURE CENTERED OFFSHORE AND
LOW PRESSURE INLAND WITH A GRADUAL TREND OF INCREASING NORTH WINDS
INTO THE WEEKEND. THIS IS LIKELY TO RESULT IN SMALL CRAFT
ADVISORY LEVEL WINDS AND SEAS IN THE OUTER WATERS SOUTH OF CAPE
BLANCO ON SATURDAY THEN ACROSS A LARGER PORTION OF THE WATERS ON
SUNDAY...WITH THE STRONGEST WINDS REMAINING IN THE OUTER WATERS
SOUTH OF CAPE BLANCO. THE INFLUENCE ON SEA HEIGHTS WILL REMAIN
RELATIVELY BALANCED BETWEEN WIND WAVE AND SWELL THROUGH SATURDAY
THEN THE STRONGER WINDS WILL TIP THE BALANCE ON SUNDAY. MODERATE
WINDS AND SEAS MAY CONTINUE THROUGH THE FIRST HALF OF NEXT WEEK WITH
A CONTINUATION OF HIGH PRESSURE OFFSHORE AND LOW PRESSURE INLAND.
/DW
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
$$
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1027 PM EDT FRI AUG 15 2014
.SYNOPSIS...
RELATIVELY DRY HIGH PRESSURE WILL PERSIST OVER THE REGION THROUGH
THE WEEKEND. MOISTURE WILL GRADUALLY INCREASE INTO EARLY NEXT WEEK
ON IMPROVING SOUTHWEST FLOW. A SERIES OF LOW PRESSURE SYSTEMS
PASSING BY TO THE NORTH EARLY NEXT WEEK WILL INCREASE THE CHANCES OF
SHOWERS AND THUNDERSTORMS THROUGH MID WEEK...ESPECIALLY OVER THE
MOUNTAINS.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 1020 PM...INFRARED SATELLITE IMAGES CONTINUE TO STREAM ACROSS
THE NORTHERN TIER OF THE CWA. I WILL UPDATE TO INCREASE CLOUD
COVER...MAINTAINING THE CLOUDY TREND THROUGH THE LATE NIGHT HOURS.
OTHERWISE...THE CURRENT FORECAST REMAINS IN GOOD CONDITION.
AS OF 730 PM...LATEST RADAR IMAGES INDICATE A LONE CELL OVER EASTERN
MCDOWELL CO. RECENT IR SATELLITE IMAGES SHOW A BAND OF HIGH CLOUDS
STREAMING SE ACROSS THE TN LINE. I WILL UPDATE THE FORECAST TO
ADJUST SKY AND POP TIMING. TEMPERATURE TRENDS LOOK GOOD AT THIS TIME.
AS OF 230 PM EDT FRIDAY...BROAD LONGWAVE UPPER TROF CONTINUES TO
SLOWLY MIGRATE EAST LEADING TO CONTINUED NORTHWEST FLOW ALOFT FOR
THE CENTRAL/SOUTHERN APPS. AT THE SURFACE...HIGH PRESSURE SLIDING
SOUTH ACROSS THE OHIO VALLEY HAS SPREAD A WEAK BACK DOOR FRONTAL
BOUNDARY ACROSS PORTIONS OF KY/WV AND INTO WESTERN VA. SCATTERED TO
BROKEN HIGH/MID LEVEL CLOUDINESS CONTINUES TO STREAM IN ALONG THE
MEAN FLOW ACROSS PORTIONS OF WESTERN NC AS STEEPENING LAPSE RATES
HAVE YIELDED DEVELOPMENT OF A FAIR WX CU FIELD REGIONWIDE. KEPT
PREVIOUS SLIGHT CHANCE POPS ACROSS PORTIONS OF THE SOUTHWEST
MOUNTAINS ALONG THE MORE CLIMO FAVORED REGIONS...HOWEVER WITH LOW
CONFIDENCE. ELSEHWERE...FCST IS DRY WITH LIGHT SOUTHWESTERLY FLOW
PREVAILING LEADING TO A NICE EVENING AHEAD.
FOR SATURDAY...ANOTHER NICE DAY IN STORE AS UPPER HEIGHTS CONTINUE
TO RISE AS TROF DEPARTS. HIGH PRESSURE WILL SLIDE OVERHEAD BEFORE
EVENTUALLY SETTING UP ON THE EASTERN SEABOARD BY THE END OF THE
PERIOD. IN RESPONSE...EXPECTING FURTHER WARMING AS SOUTHWESTERLY
FLOW CONTINUES TO DOMINATE. FCST ON SATURDAY WILL REMAIN DRY AS
CAPPING INVERSION HOLDS DUE TO WARMING ALOFT AND MIXING SURFACE
DEWPOINTS. TEMPERATURES ON SATURDAY WILL RETURN TO NEAR NORMAL
LEVELS REGIONWIDE.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AT 200 PM EDT FRIDAY...HEIGHTS WILL RISE OVER THE SE U.S. THROUGH
SUNDAY AS THE UPPER TROUGH MOVES EAST AND A SHORT WAVE APPROACHES
FROM THE WEST. THE SHORT WAVE TROUGH WILL THEN MOVE ACROSS THE AREA
ON MONDAY. AT THE SURFACE...HIGH PRESSURE INTIALLY CENTERED OVER THE
MID-ATLANTIC STATES WILL SHIFT EAST AND WEAKEN LEAVING THE AREA
UNDER THE WESTERN PERIPHERY OF THE WESTERN ATLANTIC SUBTROPICAL
RIDGE INTO MONDAY. A WEAK COLD FRONT/TROUGH ASSOCIATED WITH A
SURFACE LOW MOVING THROUGH THE OHIO VALLEY WILL REACH THE AREA ON
MONDAY.
IN REGARD TO SENSIBLE WEATHER...WITH A SHORT WAVE RIDGE DEVELOPING
OVER THE REGION ON SUNDAY EXPECT THAT CONVECTION WILL BE ESSENTIALLY
CAPPED. THEREFORE...ONLY SLIGHT CHANCE POPS OVER THE MOUNTAINS ARE
WARRANTED. ON SUNDAY NIGHT AS THE SHORT WAVE APPROACHES FROM THE
WEST...DEVELOPING DPVA...UPPER DIVERGENCE AND ELEVATED CAPE MAY
SUPPORT A FEW THUNDERSTORMS OVER THE MOUNTAINS. THEREFORE...WILL
RAMP POPS UPWARD INTO THE CHANCE RANGE. ON MONDAY AS THE UPPER
TROUGH SWINGS THROUGH ALONG WITH WEAK SURFACE CONVERGENCE ALONG THE
ADVANCING FRONT/TROUGH EXPECT TO SEE WIDELY SCATTERED TO SCATTERED
THUNDERSTORMS. GREATEST COVERAGE SHOULD BE OVER THE MOUNTAINS AS
DEEP LAYER SW/W DOWNSLOPE FLOW USUALLY LIMITS CONVECTIVE COVERAGE
OUTSIDE THE MOUNTAINS. WIND FIELDS WILL BE INCREASING ON MONDAY...
BUT SEVERE THREAT LOOKS TO BE ON THE LOW END WITH UNIDIRECTIONAL
FLOW. TEMPS WILL BE A COUPLE DEGREES ABOVE CLIMO ON SUNDAY AND NEAR
CLIMO ON MONDAY.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 230 PM FRIDAY...NEARLY ZONAL FLOW THAT STARTS ACROSS THE AREA
AT THE BEGINNING OF THE PERIOD IS SLOWLY PUSHED NORTHWARD AS THE
SUBTROPICAL RIDGE BUILDS BACK INTO THE SERN CONUS. THE CENTER OF THE
RIDGE MOVES WEST TO THE LOWER MS VALLEY BY FRI...POSSIBLY BRINGING A
RETURN TO THE NWLY FLOW ACROSS OUR CWFA. THERE IS SOME DISAGREEMENT
ON THE STRENGTH AND POSITION OF THE RIDGING. A WEAKER AND FARTHER
SOUTH RIDGE WOULD KEEP THE ZONAL FLOW CLOSER TO OUR CWFA...
POTENTIALLY BRINGING MCS ACTIVITY NEAR OR OVER THE AREA. FOR NOW...
THE RIDGE LOOKS TO KEEP THE ACTIVITY NORTH OF THE AREA. AT THE
SFC...A STATIONARY FRONT WILL REMAIN DRAPED ACROSS THE OH VALLEY
INTO THE MID ATLANTIC...WITH A LEE TROF FARTHER EAST THAN USUAL...
NEAR THE FALL LINE OF THE CAROLINAS. A WARM HUMID AIR MASS REMAINS
ACROSS THE AREA THRU THE PERIOD WITH INSTABILITY DEVELOPING EACH
AFTERNOON. HOWEVER...GIVEN THE LACK OF FORCING AND THE EASTERN
POSITION OF THE LEE TROF...DIURNAL POP WILL REVERT TO A MORE OR LESS
TYPICAL PATTERN...GENERALLY SCT MTNS TO ISOLATED PIEDMONT. WITH
HEIGHTS BUILDING THRU THE PERIOD...TEMPS START OUT NEAR NORMAL AND
END UP ABOVE NORMAL BY THE END OF THE PERIOD.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT AND ELSEWHERE...VFR EAST OF THE MTNS THROUGH THE 0Z TAF
PERIOD. THROUGH SAT...BROAD SFC HIGH PRESSURE WILL REMAIN ACROSS THE
WESTERN CAROLINAS...AS A TROF REMAINS ACROSS THE MIDLANDS AND
COASTAL PLAIN. DEWPOINTS HAVE RECOVERED 1 TO 3 DEGREES OVER THE PAST
24 HOURS. FORECAST SOUNDINGS AND HRRR CONDENSATION PRESSURE DEFICITS
INDICATE THAT MTN VALLEY FOG MAY DEVELOP AROUND DAWN. I WILL TEMPO
IFR FOG AT KAVL BETWEEN 9-12Z. OTHERWISE...CONDITIONS SHOULD REMAIN
VFR WITH LIGHT SOUTHWEST WINDS AND FEW TO SCT CU TO MID CLOUDS.
OUTLOOK...VFR CONDITIONS WILL CONTINUE THROUGH THE WEEKEND WITH THE
EXCEPTION OF PATCHY DAYBREAK FOG. VSBY/CIG/WX RESTRICTIONS WILL BE
POSSIBLE YET AGAIN INTO THE NEW WORK WEEK AS A SERIES OF WAVES PASS
THROUGH THE REGION WITH THE GREATEST CHANCES FOR RAIN BEINGS ON
MONDAY AND REMAINS THROUGH WEDNESDAY.
CONFIDENCE TABLE...
02-08Z 08-14Z 14-20Z 20-02Z
KCLT HIGH 100% MED 72% HIGH 90% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 87% HIGH 91% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 87% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 91% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...RWH
NEAR TERM...CDG/NED
SHORT TERM...LG
LONG TERM...RWH
AVIATION...NED
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
744 PM EDT FRI AUG 15 2014
.SYNOPSIS...
RELATIVELY DRY HIGH PRESSURE WILL PERSIST OVER THE REGION THROUGH
THE WEEKEND. MOISTURE WILL GRADUALLY INCREASE INTO EARLY NEXT WEEK
ON IMPROVING SOUTHWEST FLOW. A SERIES OF LOW PRESSURE SYSTEMS
PASSING BY TO THE NORTH EARLY NEXT WEEK WILL INCREASE THE CHANCES OF
SHOWERS AND THUNDERSTORMS THROUGH MID WEEK...ESPECIALLY OVER THE
MOUNTAINS.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 730 PM...LATEST RADAR IMAGES INDICATE A LONE CELL OVER EASTERN
MCDOWELL CO. RECENT IR SATELLITE IMAGES SHOW A BAND OF HIGH CLOUDS
STREAMING SE ACROSS THE TN LINE. I WILL UPDATE THE FORECAST TO
ADJUST SKY AND POP TIMING. TEMPERATURE TRENDS LOOK GOOD AT THIS TIME.
AS OF 230 PM EDT FRIDAY...BROAD LONGWAVE UPPER TROF CONTINUES TO
SLOWLY MIGRATE EAST LEADING TO CONTINUED NORTHWEST FLOW ALOFT FOR
THE CENTRAL/SOUTHERN APPS. AT THE SURFACE...HIGH PRESSURE SLIDING
SOUTH ACROSS THE OHIO VALLEY HAS SPREAD A WEAK BACK DOOR FRONTAL
BOUNDARY ACROSS PORTIONS OF KY/WV AND INTO WESTERN VA. SCATTERED TO
BROKEN HIGH/MID LEVEL CLOUDINESS CONTINUES TO STREAM IN ALONG THE
MEAN FLOW ACROSS PORTIONS OF WESTERN NC AS STEEPENING LAPSE RATES
HAVE YIELDED DEVELOPMENT OF A FAIR WX CU FIELD REGIONWIDE. KEPT
PREVIOUS SLIGHT CHANCE POPS ACROSS PORTIONS OF THE SOUTHWEST
MOUNTAINS ALONG THE MORE CLIMO FAVORED REGIONS...HOWEVER WITH LOW
CONFIDENCE. ELSEHWERE...FCST IS DRY WITH LIGHT SOUTHWESTERLY FLOW
PREVAILING LEADING TO A NICE EVENING AHEAD.
FOR SATURDAY...ANOTHER NICE DAY IN STORE AS UPPER HEIGHTS CONTINUE
TO RISE AS TROF DEPARTS. HIGH PRESSURE WILL SLIDE OVERHEAD BEFORE
EVENTUALLY SETTING UP ON THE EASTERN SEABOARD BY THE END OF THE
PERIOD. IN RESPONSE...EXPECTING FURTHER WARMING AS SOUTHWESTERLY
FLOW CONTINUES TO DOMINATE. FCST ON SATURDAY WILL REMAIN DRY AS
CAPPING INVERSION HOLDS DUE TO WARMING ALOFT AND MIXING SURFACE
DEWPOINTS. TEMPERATURES ON SATURDAY WILL RETURN TO NEAR NORMAL
LEVELS REGIONWIDE.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AT 200 PM EDT FRIDAY...HEIGHTS WILL RISE OVER THE SE U.S. THROUGH
SUNDAY AS THE UPPER TROUGH MOVES EAST AND A SHORT WAVE APPROACHES
FROM THE WEST. THE SHORT WAVE TROUGH WILL THEN MOVE ACROSS THE AREA
ON MONDAY. AT THE SURFACE...HIGH PRESSURE INTIALLY CENTERED OVER THE
MID-ATLANTIC STATES WILL SHIFT EAST AND WEAKEN LEAVING THE AREA
UNDER THE WESTERN PERIPHERY OF THE WESTERN ATLANTIC SUBTROPICAL
RIDGE INTO MONDAY. A WEAK COLD FRONT/TROUGH ASSOCIATED WITH A
SURFACE LOW MOVING THROUGH THE OHIO VALLEY WILL REACH THE AREA ON
MONDAY.
IN REGARD TO SENSIBLE WEATHER...WITH A SHORT WAVE RIDGE DEVELOPING
OVER THE REGION ON SUNDAY EXPECT THAT CONVECTION WILL BE ESSENTIALLY
CAPPED. THEREFORE...ONLY SLIGHT CHANCE POPS OVER THE MOUNTAINS ARE
WARRANTED. ON SUNDAY NIGHT AS THE SHORT WAVE APPROACHES FROM THE
WEST...DEVELOPING DPVA...UPPER DIVERGENCE AND ELEVATED CAPE MAY
SUPPORT A FEW THUNDERSTORMS OVER THE MOUNTAINS. THEREFORE...WILL
RAMP POPS UPWARD INTO THE CHANCE RANGE. ON MONDAY AS THE UPPER
TROUGH SWINGS THROUGH ALONG WITH WEAK SURFACE CONVERGENCE ALONG THE
ADVANCING FRONT/TROUGH EXPECT TO SEE WIDELY SCATTERED TO SCATTERED
THUNDERSTORMS. GREATEST COVERAGE SHOULD BE OVER THE MOUNTAINS AS
DEEP LAYER SW/W DOWNSLOPE FLOW USUALLY LIMITS CONVECTIVE COVERAGE
OUTSIDE THE MOUNTAINS. WIND FIELDS WILL BE INCREASING ON MONDAY...
BUT SEVERE THREAT LOOKS TO BE ON THE LOW END WITH UNIDIRECTIONAL
FLOW. TEMPS WILL BE A COUPLE DEGREES ABOVE CLIMO ON SUNDAY AND NEAR
CLIMO ON MONDAY.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 230 PM FRIDAY...NEARLY ZONAL FLOW THAT STARTS ACROSS THE AREA
AT THE BEGINNING OF THE PERIOD IS SLOWLY PUSHED NORTHWARD AS THE
SUBTROPICAL RIDGE BUILDS BACK INTO THE SERN CONUS. THE CENTER OF THE
RIDGE MOVES WEST TO THE LOWER MS VALLEY BY FRI...POSSIBLY BRINGING A
RETURN TO THE NWLY FLOW ACROSS OUR CWFA. THERE IS SOME DISAGREEMENT
ON THE STRENGTH AND POSITION OF THE RIDGING. A WEAKER AND FARTHER
SOUTH RIDGE WOULD KEEP THE ZONAL FLOW CLOSER TO OUR CWFA...
POTENTIALLY BRINGING MCS ACTIVITY NEAR OR OVER THE AREA. FOR NOW...
THE RIDGE LOOKS TO KEEP THE ACTIVITY NORTH OF THE AREA. AT THE
SFC...A STATIONARY FRONT WILL REMAIN DRAPED ACROSS THE OH VALLEY
INTO THE MID ATLANTIC...WITH A LEE TROF FARTHER EAST THAN USUAL...
NEAR THE FALL LINE OF THE CAROLINAS. A WARM HUMID AIR MASS REMAINS
ACROSS THE AREA THRU THE PERIOD WITH INSTABILITY DEVELOPING EACH
AFTERNOON. HOWEVER...GIVEN THE LACK OF FORCING AND THE EASTERN
POSITION OF THE LEE TROF...DIURNAL POP WILL REVERT TO A MORE OR LESS
TYPICAL PATTERN...GENERALLY SCT MTNS TO ISOLATED PIEDMONT. WITH
HEIGHTS BUILDING THRU THE PERIOD...TEMPS START OUT NEAR NORMAL AND
END UP ABOVE NORMAL BY THE END OF THE PERIOD.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT AND ELSEWHERE...VFR EAST OF THE MTNS THROUGH THE 0Z TAF
PERIOD. THROUGH SAT...BROAD SFC HIGH PRESSURE WILL REMAIN ACROSS THE
WESTERN CAROLINAS...AS A TROF REMAINS ACROSS THE MIDLANDS AND
COASTAL PLAIN. DEWPOINTS HAVE RECOVERED 1 TO 3 DEGREES OVER THE PAST
24 HOURS. FORECAST SOUNDINGS AND HRRR CONDENSATION PRESSURE DEFICITS
INDICATE THAT MTN VALLEY FOG MAY DEVELOP AROUND DAWN. I WILL TEMPO
IFR FOG AT KAVL BETWEEN 9-12Z. OTHERWISE...CONDITIONS SHOULD REMAIN
VFR WITH LIGHT SOUTHWEST WINDS AND FEW TO SCT CU TO MID CLOUDS.
OUTLOOK...VFR CONDITIONS WILL CONTINUE THROUGH THE WEEKEND WITH THE
EXCEPTION OF PATCHY DAYBREAK FOG. VSBY/CIG/WX RESTRICTIONS WILL BE
POSSIBLE YET AGAIN INTO THE NEW WORK WEEK AS A SERIES OF WAVES PASS
THROUGH THE REGION WITH THE GREATEST CHANCES FOR RAIN BEINGS ON
MONDAY AND REMAINS THROUGH WEDNESDAY.
CONFIDENCE TABLE...
23-05Z 05-11Z 11-17Z 17-23Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% MED 74% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 83% HIGH 94% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 91% 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...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...RWH
NEAR TERM...CDG/NED
SHORT TERM...LG
LONG TERM...RWH
AVIATION...NED
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1019 PM CDT FRI AUG 15 2014
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 333 PM CDT FRI AUG 15 2014
AT THE SURFACE...WEAK LOW LEVEL CONVERGENCE AXIS ALONG THE FAR
WESTERN BORDER OF CWA THIS EVENING...WITH UPPER LEVELS FEATURING
DEFORMATION AXIS ALONG WITH SEVERAL WEAK WAVES WERE PRESENT OVER THE
NORTHERN PLAINS. ATMOSPHERE REMAINS VERY MOIST WITH PRECIPITABLE
WATER FROM 1.5 TO 1.8 INCHES...BUT OVERALL INSTABILITY IS FAIRLY
MEAGER /500-1000 J/KG AT MOST/ AND CLOUDS AND PRECIP HAVE KEPT A
LITTLE CAPPING IN PLACE TOWARD SURFACE BASED CONVECTION.
WITH THERMAL ADVECTION FAIRLY UNFOCUSED OVER THE NEXT 12-24
HOURS...PRETTY MUCH FOLLOWED THE LOCATION OF THE MID LEVEL VORTICITY
AXIS TO MAP PRECIPITATION CHANCES THROUGH THE IMMEDIATE TERM.
HOWEVER...FOR THIS EVENING...THE SUBTROPICAL PORTION OF WAVE WILL
BEGIN TO SINK SOUTHEAST ACROSS NEBRASKA EARLY THIS EVENING...AND
LEAVE MUCH OF THE AREA IN WEAK TO NON EXISTENT FORCING BETWEEN THE
FIRST IMPULSE LOCATED ALONG THE VORTEX AXIS IN IOWA...AND THE SECOND
WANDERING IN WESTERN NORTH DAKOTA. LOCATION OF SUCH FICKLE FEATURES
WILL PRETTY MUCH DRIVE THE MORE CONCENTRATED CHANCES FOR
PRECIPITATION OVER THE NEXT DAY. ERRONEOUS INSTABILITY APPEARS TO
BE THE CULPRIT FOR VARIOUS SHORT TERM HIGH RESOLUTION MODELS IN
PRECIPITATION DEVELOPMENT...AND HAVE SHOWN SOME PREFERENCE TO
OVERALL DRIER SUGGESTED BY HRRR WHICH PRETTY HAS TRENDED TO HAVING
MUCH OF ANY THREAT FOR PRECIP BY EARLY EVENING. WEAK MEAN WIND
SPEEDS WILL ALSO MEAN THAT PRECIPITATION WILL NOT SO MUCH MOVE INTO
ANY AREA AND WILL HAVE TO DEVELOP IN PLACE.
STRATUS EXPECTED TO DEVELOP LATER IN THE NIGHT WITH WEAK FLOW AND
ABUNDANT LOW LEVEL MOISTURE...WHICH WILL IMPACT POTENTIAL FOR TEMPS
ON SATURDAY. WHILE TEMPS LARGELY DEPENDENT ON CLOUDS/PRECIP...HAVE
SIDED SOMEWHAT COOLER THAN MEAN GUIDANCE...ESPECIALLY IN MORE
PRECIPITATION FAVORED WEST/JAMES VALLEY.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 333 PM CDT FRI AUG 15 2014
ON SATURDAY NIGHT...FOLLOWED A 500MB VORT FILAMENT AS IT MOVES
EASTWARD ACROSS OUR FORECAST AREA AS GUIDANCE FOR TIMING AND
PLACEMENT OF CONVECTIVE CHANCES. THE 500MB FLOW IS STRONGLY
DIFFLUENT...WITH NOT A LOT OF WIND UPSTAIRS TO PUSH THE INDIVIDUAL
CELLS EASTWARD. COUPLED WITH THE DAYTIME HEATING...THOUGHTS ARE THAT
LOW END LIKELY POPS ARE WARRANTED FROM THE JAMES RIVER VALLEY TO I
29 IN SOUTH DAKOTA...PLACED SQUARELY ON THE VORT FILAMENT IN THE
EARLY EVENING. POPS THEN RAPIDLY DECREASE HEADING EAST OF I 29 AS
THE FORCING MECHANISM COMES TO A HALT. AFTER EARLY EVENING...THE
CHANCE FOR RAIN WILL LIKELY WIND DOWN AS WE LOSE HEATING...COUPLED
WITH THE FACT THAT THE VORT FILAMENT ALSO WEAKENS AS IT MOVES
EASTWARD ACROSS OUR FORECAST AREA.
SUNDAYS PRECIP CHANCES ARE DIFFICULT TO FIGURE OUT. BUT IN GENERAL
IT APPEARS THAT CHANCE POPS ARE WARRANTED MAINLY EAST OF I 29 ALONG
THE DIFFLUENT FLOW ALOFT...AND KEPT THINGS DRY IN OUR FAR WESTERN
ZONES. HIGHS AND LOWS SUNDAY AND SATURDAY NIGHT LOOK NON EVENTFUL
FOR THIS TIME OF YEAR...WITH 60S PRESENT SATURDAY NIGHT...AND UPPER
70S TO MID 80S ON SUNDAY.
THE NEXT WAVE WE CAN FOLLOW IS A SYNOPTIC SCALE FEATURE WHICH THE
VARIOUS MODELS MOVE ACROSS OUR AREA LATE SUNDAY NIGHT AND MONDAY
MORNING. LIKELY POPS ARE WARRANTED FOR MOST LOCATIONS. SEVERE
CHANCES ARE NOT REAL GREAT BECAUSE MUCH OF THE CONVECTION SHOULD
REMAIN WEST OF OUR FORECAST AREA SUNDAY EVENING...AND THE MID LEVEL
WIND SHEAR IS NOT REAL STRONG.
IN THE EXTENDED PORTION OF THE FORECAST BEGINNING MONDAY NIGHT...
THE DETERMINISTIC MODELS ARE IN PRETTY GOOD AGREEMENT IN DROPPING
THE UPPER LOW/TROUGH THROUGH THE EASTERN PLAINS...PRIMARILY IN THE
FAR EASTERN DAKOTAS...MINNESOTA AND IOWA. A CORRESPONDING SURFACE
WIND SHIFT TO A NORTHWESTERLY DIRECTION FOLLOWS SUIT LATE MONDAY
NIGHT AND TUESDAY. THEN THE UPPER TROUGH EVER SO SLOWLY MOVES
EASTWARD INTO THE GREAT LAKES REGION BY WEDNESDAY. THIS IS WHERE
MODEL DISCREPANCY BEGINS...AT LEAST BETWEEN THE DETERMINISTIC GFS
AND ECMWF IN HOW QUICKLY THEY ADVANCE THE NEXT UPPER TROUGH EASTWARD
ACROSS THE PACIFIC NORTHWEST. THE ECMWF ACTUALLY SHOWS TWO WAVES...
WITH ONE PASSING QUICKLY EASTWARD IN OUR AREA WEDNESDAY NIGHT...AND
A SECOND ONE FOLLOWING THEREAFTER. THE GFS MORPHS EVERYTHING INTO
ONE LARGER WAVE WEST OF OUR FORECAST AREA. THE GEM GLOBAL IS OFF ON
ITS OWN. ALL IN ALL...IT APPEARS CHANCES FOR CONVECTION ARE NOT REAL
GREAT MONDAY NIGHT THROUGH FRIDAY. WITH THIS MUCH DISCREPANCY...
ENSEMBLE BLENDING IS THE WAY TO GO BUT DID PUT SOME CREDENCE IN THE
ECMWF WAVE PASSAGE WEDNESDAY NIGHT...WHICH GIVE DECENT CHANCE POPS
FOR MUCH OF OUR AREA.
OTHERWISE FOR TEMPERATURES...LOOKS LIKE A LOT OF 60S FOR LOWS AND
80S FOR HIGHS...WITH 850MB TEMPERATURES NOT REAL NOTEWORTHY ONE WAY
OR ANOTHER. IT DOES LOOK HUMID THROUGH THE EXTENDED PERIOD...EVEN ON
TUESDAY WHEN THE LIGHT NORTHWEST SURFACE FLOW OCCURS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1017 PM CDT FRI AUG 15 2014
WITH PLENTY OF LINGERING LOW LEVEL MOISTURE ACROSS THE
REGION....BELIEVE MVFR TO IFR STRATUS WILL CONTINUE TO DEVELOP
TONIGHT AND WILL BE STUBBORN TO ERODE THROUGH THE MORNING HOURS ON
SATURDAY. CONDITIONS ARE EXPECTED TO RETURN TO NEAR VFR TOWARDS
18Z...AND WILL REMAIN SO THROUGH THE AFTERNOON HOURS ON SATURDAY.
THERE IS A LOW CHANCE FOR THUNDERSTORMS SATURDAY AFTERNOON...BUT
PRECISE TIMING IS NOT AT A CONFIDENCE LEVEL TO INCLUDE IN THE TAFS
AT THIS POINT.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...CHAPMAN
LONG TERM...MJ
AVIATION...
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
636 PM CDT FRI AUG 15 2014
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 333 PM CDT FRI AUG 15 2014
AT THE SURFACE...WEAK LOW LEVEL CONVERGENCE AXIS ALONG THE FAR
WESTERN BORDER OF CWA THIS EVENING...WITH UPPER LEVELS FEATURING
DEFORMATION AXIS ALONG WITH SEVERAL WEAK WAVES WERE PRESENT OVER THE
NORTHERN PLAINS. ATMOSPHERE REMAINS VERY MOIST WITH PRECIPITABLE
WATER FROM 1.5 TO 1.8 INCHES...BUT OVERALL INSTABILITY IS FAIRLY
MEAGER /500-1000 J/KG AT MOST/ AND CLOUDS AND PRECIP HAVE KEPT A
LITTLE CAPPING IN PLACE TOWARD SURFACE BASED CONVECTION.
WITH THERMAL ADVECTION FAIRLY UNFOCUSED OVER THE NEXT 12-24
HOURS...PRETTY MUCH FOLLOWED THE LOCATION OF THE MID LEVEL VORTICITY
AXIS TO MAP PRECIPITATION CHANCES THROUGH THE IMMEDIATE TERM.
HOWEVER...FOR THIS EVENING...THE SUBTROPICAL PORTION OF WAVE WILL
BEGIN TO SINK SOUTHEAST ACROSS NEBRASKA EARLY THIS EVENING...AND
LEAVE MUCH OF THE AREA IN WEAK TO NON EXISTENT FORCING BETWEEN THE
FIRST IMPULSE LOCATED ALONG THE VORTEX AXIS IN IOWA...AND THE SECOND
WANDERING IN WESTERN NORTH DAKOTA. LOCATION OF SUCH FICKLE FEATURES
WILL PRETTY MUCH DRIVE THE MORE CONCENTRATED CHANCES FOR
PRECIPITATION OVER THE NEXT DAY. ERRONEOUS INSTABILITY APPEARS TO
BE THE CULPRIT FOR VARIOUS SHORT TERM HIGH RESOLUTION MODELS IN
PRECIPITATION DEVELOPMENT...AND HAVE SHOWN SOME PREFERENCE TO
OVERALL DRIER SUGGESTED BY HRRR WHICH PRETTY HAS TRENDED TO HAVING
MUCH OF ANY THREAT FOR PRECIP BY EARLY EVENING. WEAK MEAN WIND
SPEEDS WILL ALSO MEAN THAT PRECIPITATION WILL NOT SO MUCH MOVE INTO
ANY AREA AND WILL HAVE TO DEVELOP IN PLACE.
STRATUS EXPECTED TO DEVELOP LATER IN THE NIGHT WITH WEAK FLOW AND
ABUNDANT LOW LEVEL MOISTURE...WHICH WILL IMPACT POTENTIAL FOR TEMPS
ON SATURDAY. WHILE TEMPS LARGELY DEPENDENT ON CLOUDS/PRECIP...HAVE
SIDED SOMEWHAT COOLER THAN MEAN GUIDANCE...ESPECIALLY IN MORE
PRECIPITATION FAVORED WEST/JAMES VALLEY.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 333 PM CDT FRI AUG 15 2014
ON SATURDAY NIGHT...FOLLOWED A 500MB VORT FILAMENT AS IT MOVES
EASTWARD ACROSS OUR FORECAST AREA AS GUIDANCE FOR TIMING AND
PLACEMENT OF CONVECTIVE CHANCES. THE 500MB FLOW IS STRONGLY
DIFFLUENT...WITH NOT A LOT OF WIND UPSTAIRS TO PUSH THE INDIVIDUAL
CELLS EASTWARD. COUPLED WITH THE DAYTIME HEATING...THOUGHTS ARE THAT
LOW END LIKELY POPS ARE WARRANTED FROM THE JAMES RIVER VALLEY TO I
29 IN SOUTH DAKOTA...PLACED SQUARELY ON THE VORT FILAMENT IN THE
EARLY EVENING. POPS THEN RAPIDLY DECREASE HEADING EAST OF I 29 AS
THE FORCING MECHANISM COMES TO A HALT. AFTER EARLY EVENING...THE
CHANCE FOR RAIN WILL LIKELY WIND DOWN AS WE LOSE HEATING...COUPLED
WITH THE FACT THAT THE VORT FILAMENT ALSO WEAKENS AS IT MOVES
EASTWARD ACROSS OUR FORECAST AREA.
SUNDAYS PRECIP CHANCES ARE DIFFICULT TO FIGURE OUT. BUT IN GENERAL
IT APPEARS THAT CHANCE POPS ARE WARRANTED MAINLY EAST OF I 29 ALONG
THE DIFFLUENT FLOW ALOFT...AND KEPT THINGS DRY IN OUR FAR WESTERN
ZONES. HIGHS AND LOWS SUNDAY AND SATURDAY NIGHT LOOK NON EVENTFUL
FOR THIS TIME OF YEAR...WITH 60S PRESENT SATURDAY NIGHT...AND UPPER
70S TO MID 80S ON SUNDAY.
THE NEXT WAVE WE CAN FOLLOW IS A SYNOPTIC SCALE FEATURE WHICH THE
VARIOUS MODELS MOVE ACROSS OUR AREA LATE SUNDAY NIGHT AND MONDAY
MORNING. LIKELY POPS ARE WARRANTED FOR MOST LOCATIONS. SEVERE
CHANCES ARE NOT REAL GREAT BECAUSE MUCH OF THE CONVECTION SHOULD
REMAIN WEST OF OUR FORECAST AREA SUNDAY EVENING...AND THE MID LEVEL
WIND SHEAR IS NOT REAL STRONG.
IN THE EXTENDED PORTION OF THE FORECAST BEGINNING MONDAY NIGHT...
THE DETERMINISTIC MODELS ARE IN PRETTY GOOD AGREEMENT IN DROPPING
THE UPPER LOW/TROUGH THROUGH THE EASTERN PLAINS...PRIMARILY IN THE
FAR EASTERN DAKOTAS...MINNESOTA AND IOWA. A CORRESPONDING SURFACE
WIND SHIFT TO A NORTHWESTERLY DIRECTION FOLLOWS SUIT LATE MONDAY
NIGHT AND TUESDAY. THEN THE UPPER TROUGH EVER SO SLOWLY MOVES
EASTWARD INTO THE GREAT LAKES REGION BY WEDNESDAY. THIS IS WHERE
MODEL DISCREPANCY BEGINS...AT LEAST BETWEEN THE DETERMINISTIC GFS
AND ECMWF IN HOW QUICKLY THEY ADVANCE THE NEXT UPPER TROUGH EASTWARD
ACROSS THE PACIFIC NORTHWEST. THE ECMWF ACTUALLY SHOWS TWO WAVES...
WITH ONE PASSING QUICKLY EASTWARD IN OUR AREA WEDNESDAY NIGHT...AND
A SECOND ONE FOLLOWING THEREAFTER. THE GFS MORPHS EVERYTHING INTO
ONE LARGER WAVE WEST OF OUR FORECAST AREA. THE GEM GLOBAL IS OFF ON
ITS OWN. ALL IN ALL...IT APPEARS CHANCES FOR CONVECTION ARE NOT REAL
GREAT MONDAY NIGHT THROUGH FRIDAY. WITH THIS MUCH DISCREPANCY...
ENSEMBLE BLENDING IS THE WAY TO GO BUT DID PUT SOME CREDENCE IN THE
ECMWF WAVE PASSAGE WEDNESDAY NIGHT...WHICH GIVE DECENT CHANCE POPS
FOR MUCH OF OUR AREA.
OTHERWISE FOR TEMPERATURES...LOOKS LIKE A LOT OF 60S FOR LOWS AND
80S FOR HIGHS...WITH 850MB TEMPERATURES NOT REAL NOTEWORTHY ONE WAY
OR ANOTHER. IT DOES LOOK HUMID THROUGH THE EXTENDED PERIOD...EVEN ON
TUESDAY WHEN THE LIGHT NORTHWEST SURFACE FLOW OCCURS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 631 PM CDT FRI AUG 15 2014
WITH PLENTY OF LINGERING LOW LEVEL MOISTURE ACROSS THE
REGION....BELIEVE MVFR TO IFR STRATUS WILL DEVELOP AFTER 06Z
TONIGHT AND WILL BE STUBBORN TO ERODE THROUGH THE MORNING HOURS ON
SATURDAY. CONDITIONS ARE EXPECTED TO RETURN TO NEAR VFR TOWARDS
18Z...AND WILL REMAIN SO THROUGH THE AFTERNOON HOURS ON SATURDAY.
THERE IS THE POTENTIAL FOR THUNDERSTORMS SATURDAY AFTERNOON...BUT
PRECISE TIMING IS NOT AT A CONFIDENCE LEVEL TO INCLUDE IN THE TAFS
AT THIS POINT.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...CHAPMAN
LONG TERM...MJ
AVIATION...
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1102 PM MDT WED AUG 13 2014
.SHORT TERM...THIS EVENING THROUGH THURSDAY NIGHT
ISSUED AT 247 PM MDT WED AUG 13 2014
UPPER RIDGING ACROSS THE CENTRAL CONUS CONTINUES WITH AN UPPER LOW
OVER THE PACIFIC NW. DEEP SWRLY FLOW HAS DEVELOPED ACROSS THE DESERT
SW INTO THE GREAT BASIN AND CNTRL ROCKIES...WITH INCREASING
MONSOONAL MOISTURE OVER MUCH OF THE WRN CONUS. A SERIES OF UPPER
WAVES ARE CROSS WY/ERN MT ATTM...WITH A MUCH STRONGER WAVE OVER
AZ/UT. STORMS HAVE ALREADY FIRED AHEAD OF THE FIRST WAVE NOW
CROSSING THE WRN/CNTRL CWA. RAP MODEL IS SHOWING 3000 J/KG
MLCAPE...BUT WITH A CAP IN PLACE...CONVECTION HAS BEEN LIMITED TO
HIGHER TERRAIN OF THE BLKHLS. HRRR SHOWS MORE STORMS DEVELOPING OVER
THE NEXT HOUR OR TWO ACROSS NE WY AND PUSHING EAST THROUGH THE EVNG
HOURS. MOST OF THE STORM ACTIVITY WOULD BE EAST OF THE CWA BY 06Z
WITH LINGERING SHOWERS POSSIBLE. WEAK SHEAR WILL KEEP STORMS FROM
REACHING SEVERE...THOUGH WITH STRONG INSTABILITY CANT RULE OUT A
STORM OR TWO PRODUCING SMALL HAIL AND GUSTY WINDS LIKE THE STORM
OVER THE NORTHERN BLACK HILLS LIKELY DID EARLIER THIS AFTERNOON.
STRONG WAVE OVER THE SWRN CONUS WILL SLIDE NE TONIGHT...THEN CROSS
THE CWA LATE THURSDAY. MONSOONAL FLOW WILL RESULT IN INCREASINGLY
MOIST PROFILES THROUGH THE DAY THURSDAY WITH PWATS FORECAST TO BE
180 PERCENT OF NORMAL OR MORE. WIND PROFILES SUGGEST STORMS WILL BE
SLOW MOVING WITH MEAN STORM MOTION UNDER 10KT. STORMS WILL CONTINUE
THROUGH THURSDAY NIGHT AS THE SYSTEM SLOWLY MOVES E/NE INTO ND/CNTRL
SD. WITH THE HEAVY RAINS THAT MANY AREAS HAVE RECEIVED IN THE LAST
WEEK...THINK THERE WILL BE A POTENTIAL FOR FLASH FLOODING THURSDAY
AFTERNOON AND THROUGH THURSDAY NIGHT. HAVE ISSUED A FLASH FLOOD
WATCH FOR THIS TIME PERIOD.
&&
.LONG TERM...FRIDAY THROUGH WEDNESDAY
ISSUED AT 247 PM MDT WED AUG 13 2014
SEVERAL SHORTWAVES WILL AFFECT THE FORECAST AREA FROM FRIDAY INTO
EARLY NEXT WEEK...BRINGING AT LEAST A SLIGHT CHANCE OF THUNDERSTORMS
TO PARTS OF THE FORECAST AREA NEARLY EVERY DAY. ON FRIDAY...A SLOW
MOVING SHORTWAVE HAS THE POTENTIAL TO CREATE LOCALLY HEAVY
RAINFALL GIVEN WEAK 850-300MB STEERING FLOW AND MODELED GREATER THAN
150 PERCENT PRECIPITABLE WATER AMOUNTS. TEMPERATURES THROUGH THE
PERIOD WILL BE WITHIN 5 DEGREES OF THE AVERAGE FOR THIS TIME OF YEAR.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1059 PM MDT WED AUG 13 2014
AN UPPER LEVEL DISTURBANCE WILL PUSH TOWARD THE REGION WITH
INCREASING CHANCES FOR SHRA/TS THROUGH THE PERIOD. THERE IS A
SLIGHT CHANCE FOR A SHOWER OR TS TONIGHT THROUGH THUR
MORNING...WITH BETTER CHANCES FOR SHRA/TS THUR AFTERNOON/EVENING
OVER THE WESTERN 2/3. VFR CONDITIONS WILL PREVAIL OUTSIDE OF ANY
PRECIPITATION...WITH THE POTENTIAL FOR SOME MVFR STRATUS OVER
WESTERN AREAS LATE IN THE PERIOD.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...FLASH FLOOD WATCH FROM THURSDAY AFTERNOON THROUGH LATE THURSDAY
NIGHT FOR SDZ001-002-012>014-024>032-041>044-072>074.
WY...FLASH FLOOD WATCH FROM THURSDAY AFTERNOON THROUGH LATE THURSDAY
NIGHT FOR WYZ054>058-071.
&&
$$
SHORT TERM...13
LONG TERM...10
AVIATION...JC
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
250 PM CDT THU AUG 14 2014
.SHORT TERM /NOW THROUGH FRIDAY NIGHT...AFTERNOON WATER VAPOR
SHOWS DRY AIR MOVING THROUGH SOUTH TEXAS INTO THE NORTHERN
PORTIONS OF THE CWA. CRP SOUNDING SHOWED PWATS OF 1.51 INCHES.
DOWN IN THE VALLEY...MORE MOISTURE IS PRESENT WITH BRO SOUNDING OF
2.04. SEA BREEZE IS MOVING INLAND WITH A FEW SHOWERS ACROSS THE
COASTAL COUNTIES. HRRR SHOWS ISOLATED SHOWERS CONTINUING ALONG THE
SEA BREEZE WITH MOST ACTIVITY DONE AND OVER WITH BY EARLY EVENING.
HAVE SLIGHT CHANCE POPS FOLLOWING THE SEA BREEZE THROUGH THE REST
OF THE DAY. HIGHS STILL EXPECTED INTO THE MID-UPPER 90S WITH LOWER
100S ACROSS THE UPPER VALLEY.
NAM 500-300MB RH SHOWS DRY AIR ENGULFING THE AREA BY MID EVENING
WHICH WILL SHUT DOWN ANY PRECIP REMAINING. THEREFORE...SKIES WILL
CLEAR OUT AND WINDS WILL SUBSIDE ALLOWING TEMPERATURES TO FALL INTO
THE MID-UPPER 70S TO AROUND 80 DEGREES.
FRIDAY A SHORTWAVE TROUGH WILL MOVE DOWN THE EASTERN SIDE OF THE
RIDGE PARKED OVER THE SOUTHWEST WHICH WILL HELP STRENGTHEN SURFACE
TROUGHING TO OUR WEST AND STRENGTHEN WINDS ACROSS THE AREA FRIDAY
AFTERNOON THROUGH THE SHORT TERM. BREEZIER CONDITIONS EXPECTED
FRIDAY AFTERNOON IN THE VALLEY AND PROGRESSES INTO THE COASTAL
WATERS FRIDAY NIGHT. NOT MUCH IN THE WAY OF PRECIP FRIDAY WITH
LOWERED 1000-500MB RH AND PWATS FALLING TO 1.7 INCHES. DID PUT 10
POPS FOR EAST OF HWY 281 BUT NOTHING MENTIONABLE IN THE ZONES.
FAVORED THE ECMWF MOS FOR TEMPERATURES SINCE MAV/MET SEEM A LITTLE
LOW FOR THIS REGIME.
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...A PERSISTENT H5 RIDGE
WILL STRETCH FROM THE DESERT SOUTHWEST TO THE FLORIDA PENINSULA
AND WILL DOMINATE THE UPPER PATTERN THROUGH THE MAJORITY OF THE
PERIOD. THE RIDGE WILL NATURALLY EXHIBIT WEAKNESS OVER THE WEST
GULF HOWEVER... SIMPLY A REFLECTION OF THE TWO STRONGER ENDS OF
THE BARBELL TO THE EAST AND WEST. SFC HIGH PRESSURE WILL BE
SUPPORTED OVER THE NORTH AND EAST GULF...PROVIDING A MODERATE
ANTICYCLONIC FLOW OVER THE WEST GULF AND THE CWA. DRIER AIR WILL
HOLD SWAY OVER LAND AREAS WITH JUST A SILENT SLIGHT CHANCE OF RAIN
FOR THE GULF THROUGH MUCH OF THE LONG TERM. AN EXCEPTION WILL BE
NEXT WEDNESDAY WHEN A SLUG OF MOISTURE MOVES UP FROM THE SOUTH AND
APPEARS TO HAVE ENOUGH JUICE TO JUSTIFY A NONSILENT 20 PERCENT
CHANCE OF SHOWERS AND TSTMS. THIS UPTICK IN POPS REPRESENTS THE
EFFECTS OF A TROPICAL WAVE MOVING INTO THE SOUTHWEST GULF AT THAT
TIME. OTHERWISE...WITH SUCH CONSISTENCY IN THE FORECAST. THERE WAS
NOT MUCH REASON TO CHANGE THE INHERITED FORECAST SIGNIFICANTLY.
TEMPS WILL RUN SLIGHTLY ABOVE NORMAL WITH LIGHT TO MODERATE
ONSHORE WINDS AND A MIX OF CLOUDS AND SUN. AFTN HEAT LOWS INLAND
WILL TIGHTEN THE GRADIENT SOMEWHAT WITH BREEZY AND GUSTY WINDS
SHOWING UP OVER STARR AND ZAPATA COUNTIES. NO MAJOR DIFFERENCES
NOTED BETWEEN THE GFS AND ECMWF AT THIS WRITING.
&&
.MARINE...
NOW THROUGH FRIDAY NIGHT...WINDS WILL REMAIN LIGHT TO MODERATE
WITH LOW SEAS THROUGH FRIDAY MORNING. WINDS AND SEAS WILL BEGIN TO
INCREASE FRIDAY AFTERNOON AND EVENING AS LOW PRESSURE STRENGTHENS
TO OUR WEST AND INTERACTS WITH HIGH PRESSURE OVER THE GULF. SMALL
CRAFT EXERCISE CAUTION MAY BE NEEDED FOR THE LAGUNA FRIDAY AND THE
OFFSHORE WATERS FRIDAY NIGHT
SATURDAY THROUGH MONDAY...BROAD H5 RIDGING FROM THE SOUTHWEST
UNITED STATES EAST ACROSS THE GULF THROUGH THE NORTH ATLANTIC
WILL SUPPORT HIGH PRESSURE ACROSS THE NORTH GULF AT THE SURFACE.
SLIGHTLY LOWER PRESSURE WILL PERSIST OVER THE BAY OF CAMPECHE. A
SLIGHT WEAKNESS OVER THE WEST GULF SPLITTING THE MAIN RIDGE WILL
KEEP THE DOOR OPEN FOR SLIGHTLY ENHANCED MARINE SHOWER AND TSTM
ACTIVITY. MODERATE TO BREEZY SOUTH SOUTHEAST WINDS WILL PREVAIL
WITH MODERATE SEAS OF 3 TO 4 FEET WHICH MAY INCREASE A FOOT OR SO
LATE IN THE WEEKEND. SMALL CRAFT EXERCISE CAUTION CONDITIONS MAY
BE POSSIBLE FROM TIME TO TIME DUE TO STRONGER WINDS.
&&
.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL 79 96 82 95 / 10 10 10 10
BROWNSVILLE 78 96 80 96 / 10 10 10 10
HARLINGEN 77 99 80 99 / 10 10 10 10
MCALLEN 79 102 80 101 / 10 10 10 10
RIO GRANDE CITY 79 103 80 103 / 10 10 10 10
SOUTH PADRE ISLAND 81 87 83 91 / 10 10 10 10
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
55/54/65/MARTINEZ
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
1158 AM CDT THU AUG 14 2014
.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
&&
.AVIATION...MORNING WATER VAPOR IMAGERY SHOWS DRY AIR ACROSS
SOUTHERN TEXAS NOSING INTO OUR NORTHERN COUNTIES NORTH OF THE
VALLEY. DRY AIR WAS SEEN ON CRP 12Z SOUNDING BUT STILL RATHER
MOIST ON BRO SOUNDING. HRRR SHOWS SEABREEZE SHRA/TSRA DEVELOPING
AND MOVING INLAND THE FIRST COUPLE OF HOURS OF THE TAF PERIOD
BEFORE DRIER MID/UPPER LEVEL AIR MOVES IN AND SHUTS DOWN THE RAIN
CHANCES. THEREFORE...HAVE PLACED VCTS IN THE TAFS UP UNTIL 23Z.
AFTERWARDS...WINDS WILL DECREASE OVERNIGHT. FOR FRIDAY...WINDS
WILL INCREASE AND BECOME GUSTY BY 18Z AS LOW PRESSURE STRENGTHENS
TO OUR NORTHWEST.
&&
.PREV DISCUSSION... /ISSUED 603 AM CDT THU AUG 14 2014/
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
AVIATION...VFR CONDITIONS WILL PREVAIL FOR TODAY OVER THE TERMINALS
WITH LIGHT AND VARIABLY WINDS FOR THE EARLY MORNING HOURS. A FEW TO
SCT CUMULUS WILL BEGIN TO DEVELOP AS DAYTIME HEATING BEGINS WITH
VFR CONDITIONS CONTINUING. THE EAST WINDS WILL INCREASE AS THE SEA
BREEZE DEVELOPS AROUND 18Z WITH A FEW ISO SHOWERS OR THUNDERSTORM
DEVELOPING. THE WINDS WILL LOWER BETWEEN 10 TO 15 KNOTS SHIFTING
SOUTHEAST IN THE EVENING AND REMAIN LIGHT AND CALM THROUGH THE
NIGHT.
PREV DISCUSSION... /ISSUED 413 AM CDT THU AUG 14 2014/
SHORT TERM /NOW THROUGH FRIDAY...LATEST WATER VAPOR SATELLITE
IMAGERY SHOWS BROAD HIGH PRESSURE GRADUALLY SHIFTING EASTWARD INTO
THE CENTRAL PLAINS TODAY AS CLOSED LOW PRESSURE ENTERS THE PACIFIC
NORTHWEST COAST. HIGH WILL FLATTEN AND REMAIN IN CONTROL ACROSS THE
DESERT SOUTHWEST TODAY INFILTRATING DRY AIR ALOFT INTO SOUTH TEXAS.
THE CHANCES OF RAIN LOWER TODAY AND TOMORROW DUE TO THE INFLUENCE OF
THIS DRIER AIR INTO THE AREA. TODAY...EASTERLY FLOW WILL ENHANCE THE
SEA BREEZE TODAY. RH VALUES AROUND 1000 TO 500 MB RANGE FROM 50 TO
60 PERCENT ESPECIALLY OVER THE RGV WHILE OVER THE NORTHERN COUNTIES
RH VALUES REMAIN BELOW 40 TO 45 PERCENT. LEFT INHERITED 20 PERCENT
POPS ESPECIALLY FAVORING THE LOWER AND MIDDLE VALLEY. IN ADDITION...
HEIGHTS RISE ACROSS WESTERN COUNTIES AND THE 850MB TEMPS INCREASE
TO 20 TO 22 DEGREES ALLOWING FOR HIGH TEMPERATURES TO INCREASE
ACROSS THE AREA. HIGHS WILL RANGE FROM 100 TO 103 DEGREES WEST OF
HIGHWAY 281 AND THE UPPER 90S ALONG HIGHWAY 77/83 EAST INTO THE
COAST.
THURSDAY NIGHT...SURFACE LOW MOVES INTO THE AREA SHIFTING WINDS
OVERNIGHT SOUTHEAST WIND MOSTLY CLEAR SKY CONDITIONS. LOW TEMPS
WILL COOL DOWN INTO THE MID TO LOW 70S IN THE NORTHERN COUNTIES.
THE WINDS WILL REMAIN CALM OVERNIGHT WITH LOW CHANCE OF RAIN.
FRIDAY...EXPECT ALMOST A REPEAT OF THURSDAY BUT WITH LESS SHOWER
ACTIVITY ANTICIPATED AND AN INCREASE IN SOUTHEAST WINDS FOR THE
AFTERNOON HOURS AS THE INFLUENCE OF THE DRIER AIR FROM THE HIGH
PRESSURE MOVES INTO THE AREA. HEIGHTS ALSO RISE AS THE HIGH
EXPANDS ACROSS SOUTH TEXAS AND PWATS VALUES LOWER INTO 1.8 IN
WITH LESS RH VALUES AS WELL. THIS IS NOT FAVORABLE CONVECTION AS
THE SEA BREEZE DEVELOPS. HIGH TEMPERATURES RISE A FEW DEGREES
MORE WITH MORE LOCATIONS OUT WEST BETWEEN 101 TO 103 DEGREES.
PRESSURE GRADIENT WILL STRENGTHEN AS THE THERMAL LOW DEEPENS TO
WEST AND INTERACT WITH HIGH PRESSURE TO EAST ALLOWING FOR SE WINDS
TO INCREASE IN THE AFTERNOON HOURS.
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...500 MB HIGH PRESSURE
CENTERED OVER THE DESERT SOUTHWEST AND THE FLORIDA PENINSULA WILL
BE THE DOMINANT WEATHER PATTERN OVER DEEP SOUTH TEXAS THROUGHOUT
THE MAJORITY OF THE PERIOD. WITH THESE WEATHER SYSTEMS...AND AN
ATMOSPHERE DRYING TO A PRECIPITABLE WATER CONTENT OF NEAR 1.50
INCHES...DRY WEATHER WILL RESULT. THE MOST SIGNIFICANT CHANGE TO
THE LONG TERM PORTION OF THE FORECAST WAS THE INCLUSION OF A
SLIGHT CHANCE OF PRECIPITATION FOR THE EASTERN PORTION OF THE BRO
CWFA AND ADJACENT COASTAL WATERS FOR WEDNESDAY AS A WEAK INVERTED
500 MB TROUGH FORMS ALONG THE EAST COAST OF MEXICO AND BETWEEN THE
TWO 500 MB HIGHS. INHERITED VERY HOT HIGH TEMPERATURES WERE LEFT
IN PLACE WITH NO REAL GOOD REASON FOR ADJUSTING THEM DOWNWARD.
MARINE...NOW THROUGH FRIDAY...WINDS WILL REMAIN LIGHT AND MODERATE
WITH LOW SEAS THROUGH THE SHORT TERM FORECAST. CHANCE OF RAIN IS
POSSIBLE THROUGH THE DAY WITH SEA BREEZE DEVELOPING OVER THE COASTAL
WATERS AND NEAR THE COAST MOVING WESTWARD. NO SCEC OR SCA AT THIS
TIME.
FRIDAY NIGHT THROUGH WEDNESDAY...FAVORABLE MARINE CONDITIONS FRIDAY
NIGHT WILL YIELD TO STRONGER WINDS AND ROUGHER SEAS SATURDAY THROUGH
TUESDAY AS HIGH PRESSURE OVER THE GULF OF MEXICO INTERACTS WITH LOW
PRESSURE OVER TEXAS. SMALL CRAFT EXERCISE CAUTION OR SMALL CRAFT
ADVISORY ARE POSSIBLE DURING THIS TIME PERIOD FOR THE LOWER TEXAS
COASTAL WATERS. MARINE CONDITIONS MAY IMPROVE SLIGHTLY ON WEDNESDAY.
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
55
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
824 PM EDT FRI AUG 15 2014
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCES WILL TRACK SOUTHEAST ACROSS OUR
REGION TONIGHT. MEANWHILE...A FRONTAL ZONE STALLED OVER THE AREA
WILL GRADUALLY LIFT NORTH OF THE REGION AS A WARM FRONT SATURDAY
INTO SUNDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 800 PM EDT FRIDAY...
MADE SOME EARLIER ADJUSTMENTS TO POPS...WX...AND T/TD GRIDS BASED
ON LATEST TRENDS. SHOWERS AND EVEN A FEW THUNDERSTORMS DEVELOPED
LATE AFTERNOON ALONG WEEK LEE SIDE TROUGH ACROSS SOUTHSIDE AND
INTO THE VA/NC PIEDMONT. MODELS SUGGEST THIS WILL LIKELY CONTINUE
INTO THE EVENING HOURS WHILE MOVING SE WITH TIME. ADJUST POPS UP
TO LOW CHANCE IN THIS AREAS. ALL SHOULD STAY PRETTY MUCH
SOUTH/EAST OF THE BLUE RIDGE. BACKED OFF SLIGHTLY ON TSRA AS MOST
OF THE ACTIVITY WEST OF KDAN HAS BEEN JUST SHOWERS. KEPT EARLIER
IDEA OF POPS TRENDING TOWARD ZERO BY MIDNIGHT. RETAINED MENTION OF
LATE NIGHT/EARLY MORNING FOG IN FAVORABLE AREAS.
TEMPERATURES WERE RUNNING SEVERAL DEGREES HIGHER THAN
ADVERTISED...SO RAISED THEM SLIGHTLY THROUGH THE EVENING HOURS
TRENDING INTO EARLIER EXPECTED OVERNIGHT MIN TEMPS.
AS OF 332 PM EDT FRIDAY...
UPPER LEVEL TROUGH WILL REMAIN ALONG THE EAST COAST TONIGHT INTO
SATURDAY. A SHORTWAVE WILL DROP SOUTHEAST IN THE NORTHWEST FLOW
TONIGHT ACROSS THE AREA. THIS WILL COMBINE WITH A STALL FRONTAL
BOUNDARY TO CREATE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
IN THE UNSTABLE AIR THIS AFTERNOON INTO THIS EVENING. MSAS PLACED
THE MOST UNSTABLE AIR ACROSS SOUTHWEST PORTIONS WITH LI MINUS ONE
TO MINUS THREE. SPC MESOSCALE ANALYSIS HIGHLIGHTED MUCAPE ABOUT
1000 J/KG IN THE SOUTHWEST. SHAPED POPS TOWARDS HRRR FOR THIS
EVENING INTO TONIGHT.
SHOWERS OR STORMS SHOULD FADE TONIGHT WITH LOSS OF HEATING AND NO
REAL SUPPORT ALOFT WITH TIMING CLOSE TO YESTERDAY...BECAUSE HIGHER
THETA-E AIR RESIDES ACROSS THE SOUTHERN CWA INTO TONIGHT. CLEAR TO
PARTLY CLOUDY CONDITIONS EXPECTED OVERNIGHT. PATCHY VALLEY FOG
EXPECTED LATE TONIGHT IN THE USUAL PLACES AS WELL AS SOUTHSIDE VA/NW
NC PER ANY SHOWER ACTIVITY THIS AFTERNOON/EVENING. PLAYED LOW
TEMPERATURES OVERNIGHT CLOSE TO THE ADJMAVBC WITH READINGS FROM THE
MID TO UPPER 40S IN THE DEEPER MOUNTAIN VALLEYS TO THE LOWER 60S IN
THE SOUTHEAST...WITH HIGH PRESSURE MOVING OVERHEAD ACROSS THE
CENTRAL APPALACHIANS.
UPPER LEVEL TROUGHING OVER THE NORTHEAST STATES WITH GRADUALLY SHIFT
EAST ON SATURDAY...RESULTING A WEAK ZONAL UPPER LEVEL PATTERN.
FRONTAL BOUNDARY LIFTS NORTH ACROSS A WARM FRONT...AS A WAVE OF LOW
PRESSURE MOVES ACROSS EASTERN NORTH CAROLINA AND VIRGINIA SATURDAY.
MORNING LOW CLOUDS AND FOG WILL LIFT OR BURN OFF QUICKLY SATURDAY.
MAY SEE AN ISOLATED SHOWER OR STORM IN THE SOUTHEAST DURING THE
AFTERNOON NEAR THE FRONT...HOWEVER CHANCES APPEAR TOO LOW AT THIS
POINT TO ADD MENTION IN THE FORECAST WITH LIMITED LIFT. THE DAY
TWO CONVECTIVE OUTLOOK HAS PLACED THE CHANCE OF GENERAL
THUNDERSTORM WAY TO OUR EAST SATURDAY ACROSS EASTERN NORTH
CAROLINA. WENT WITH HIGH TEMPERATURES ON SATURDAY FROM AROUND 80
DEGREES IN THE MOUNTAINS TO THE UPPER 80S IN THE PIEDMONT.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
AS OF 301 PM EDT FRIDAY...
THE FORECAST PERIOD BEGINS WITH A WEAK SURFACE HIGH OVER THE
SOUTHERN APPALACHIANS AND A LEE TROUGH ACROSS THE MID ATLANTIC
COASTAL PIEDMONT. BY SUNDAY AFTERNOON...THE SURFACE HIGH WITHERS
AWAY WITH DIURNAL SHOWERS AND THUNDERSTORMS DEVELOPING ACROSS THE
MOUNTAINS. THESE STORMS ARE EXPECTED TO FADE THROUGH THE EVENING.
MODELS ARE ALSO SHOWING A SHORT WAVES TRACKING EAST BUT NORTH OF THE
AREA SUNDAY MORNING. THIS WAVE AND ASSOCIATED CONVECTION MAY LAY AN
OUTFLOW BOUNDARY ACROSS THE MOUNTAINS TO FURTHER ENHANCE THE
DEVELOPMENT OF AFTERNOON CONVECTION.
SUNDAY NIGHT INTO MONDAY...MODELS ARE MOVING A MESOSCALE COMPLEX
FROM THE OHIO VALLEY TO THE MID ATLANTIC REGION. THE 12Z GFS KEEPS
THIS COMPLEX MOVING EAST ACROSS PENNSYLVANIA MONDAY NIGHT. THE 12Z
NAM/ECM HAS A MORE SOUTHERN TRACK WITH THE COMPLEX TRACKING ACROSS
WEST VIRGINIA MONDAY AND OVER CENTRAL-NORTHERN VIRGINIA MONDAY
AFTERNOON/NIGHT. THIS SOUTHERN TRACK WOULD CLIP THE FORECAST AREA
ALONG AND NORTH OF I64. OUTFLOW BOUNDARIES MAY GENERATE STORMS
ACROSS THE REST OF THE FORECAST AREA LATE MONDAY AFTERNOON/NIGHT.
SUNDAY WILL SEE TEMPERATURES WARMER THAN NORMAL WITH A SOUTHERLY
FLOW AND ABUNDANT SUNSHINE. DESPITE THE COOL START TO THE
MONTH...SUMMER IS NOT OVER FROM A WEATHER STAND POINT. MONDAY WILL
ALSO BE A WARMER THAN NORMAL DAY...ESPECIALLY IF THE MESOSCALE
COMPLEX STAYS WELL TO THE NORTH. SINCE MODELS ARE DELAYING
CONVECTION ACROSS THE SOUTHERN TWO/THIRDS OF THE FORECAST
AREA...WILL CONTINUE TO RUN WITH THE WARMER GUIDANCE.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 100 PM EDT FRIDAY...
UNSETTLED PATTERN DURING THIS PERIOD. SEVERAL SHORTWAVES PIVOT
THROUGH THE REGION TUESDAY AND WEDNESDAY AND THEN MID LEVEL RIDGING
SETS UP FOR THE REST OF THE PERIOD...WITH ADDITIONAL DISTURBANCES
RIDING ALONG THE RIDGE FROM THE NORTHWEST INTO OUR REGION. PLENTY OF
MOISTURE AND INSTABILITY WILL BE PRESENT FOR SCATTERED SHOWERS AND
THUNDERSTORMS EACH DAY. PLACED SLIGHT CHANCE TO CHANCE POPS IN EACH
DAY WITH THE MAX POPS DURING THE AFTERNOON/EVENING HOURS...AND
SLIGHTLY LOWER POPS DURING THE OVERNIGHT HOURS.
TEMPERATURES WILL BE CLOSER TO NORMAL AS 850MB TEMPS RISE FROM +16C
AT THE BEGINNING OF THE PERIOD TO NEAR +20C BY THE WEEKEND. THIS
WILL COORDINATE TO SURFACE HIGH TEMPS NEAR 90 EAST OF THE BLUE RIDGE
AND LOW TO MID 80S FROM THE BLUE RIDGE AND POINTS TO THE WEST.
DEWPOINTS WILL HOLD IN THE MID TO UPPER 60S THROUGH THE PERIOD WHICH
WILL KEEP NIGHT TIME TEMPS ON THE MILD SIDE.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
AS OF 740 PM EDT FRIDAY...
SCATTERED SHOWERS WILL CONTINUE PUSHING SOUTH OF KMKW-KDAN LINE
THROUGH ABOUT 02Z/10PM BEFORE DISSIPATING. AN ISOLATED
THUNDERSTORM CANNOT BE RULED OUT. OVERNIGHT...MAINLY VFR
CONDITIONS AND LIGHT WINDS ARE EXPECTED. PATCHY IFR/MVFR FOG IS
EXPECTED MAINLY IN THE MOUNTAIN AND RIVER VALLEYS...AND THOSE
AREAS THAT RECEIVED RAIN TODAY.
AN SUB VFR CONDITIONS SHOULD IMPROVE QUICKLY TO VFR AFTER SUNRISE
SATURDAY.
AS OF 130 PM EDT FRIDAY...
EXPECT MAINLY VFR INTO THE WEEKEND..WITH HIGH PRESSURE IN PLACE.
HIGH CONFIDENCE IN CEILINGS...VISIBILITIES...AND WINDS DURING THE
PERIOD.
WEATHER PATTERN BECOMES MORE TYPICAL FOR AUGUST BY EARLY NEXT
WEEK. LOW PROBABILITY FOR AFTERNOON AND EVENING
THUNDERSTORMS...THEN FOG IN FAVORED VALLEY LOCATIONS OVERNIGHT.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WP
NEAR TERM...KK/RAB
SHORT TERM...RCS
LONG TERM...CF
AVIATION...DS/KK/WP
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
745 PM EDT FRI AUG 15 2014
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCES WILL TRACK SOUTHEAST ACROSS OUR
REGION TONIGHT. MEANWHILE...A FRONTAL ZONE STALLED OVER THE AREA
WILL GRADUALLY LIFT NORTH OF THE REGION AS A WARM FRONT SATURDAY
INTO SUNDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 332 PM EDT FRIDAY...
UPPER LEVEL TROUGH WILL REMAIN ALONG THE EAST COAST TONIGHT INTO
SATURDAY. A SHORTWAVE WILL DROP SOUTHEAST IN THE NORTHWEST FLOW
TONIGHT ACROSS THE AREA. THIS WILL COMBINE WITH A STALL FRONTAL
BOUNDARY TO CREATE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
IN THE UNSTABLE AIR THIS AFTERNOON INTO THIS EVENING. MSAS PLACED
THE MOST UNSTABLE AIR ACROSS SOUTHWEST PORTIONS WITH LI MINUS ONE
TO MINUS THREE. SPC MESOSCALE ANALYSIS HIGHLIGHTED MUCAPE ABOUT
1000 J/KG IN THE SOUTHWEST. SHAPED POPS TOWARDS HRRR FOR THIS
EVENING INTO TONIGHT.
SHOWERS OR STORMS SHOULD FADE TONIGHT WITH LOSS OF HEATING AND NO
REAL SUPPORT ALOFT WITH TIMING CLOSE TO YESTERDAY...BECAUSE HIGHER
THETA-E AIR RESIDES ACROSS THE SOUTHERN CWA INTO TONIGHT. CLEAR TO
PARTLY CLOUDY CONDITIONS EXPECTED OVERNIGHT. PATCHY VALLEY FOG
EXPECTED LATE TONIGHT IN THE USUAL PLACES AS WELL AS SOUTHSIDE VA/NW
NC PER ANY SHOWER ACTIVITY THIS AFTERNOON/EVENING. PLAYED LOW
TEMPERATURES OVERNIGHT CLOSE TO THE ADJMAVBC WITH READINGS FROM THE
MID TO UPPER 40S IN THE DEEPER MOUNTAIN VALLEYS TO THE LOWER 60S IN
THE SOUTHEAST...WITH HIGH PRESSURE MOVING OVERHEAD ACROSS THE
CENTRAL APPALACHIANS.
UPPER LEVEL TROUGHING OVER THE NORTHEAST STATES WITH GRADUALLY SHIFT
EAST ON SATURDAY...RESULTING A WEAK ZONAL UPPER LEVEL PATTERN.
FRONTAL BOUNDARY LIFTS NORTH ACROSS A WARM FRONT...AS A WAVE OF LOW
PRESSURE MOVES ACROSS EASTERN NORTH CAROLINA AND VIRGINIA SATURDAY.
MORNING LOW CLOUDS AND FOG WILL LIFT OR BURN OFF QUICKLY SATURDAY.
MAY SEE AN ISOLATED SHOWER OR STORM IN THE SOUTHEAST DURING THE
AFTERNOON NEAR THE FRONT...HOWEVER CHANCES APPEAR TOO LOW AT THIS
POINT TO ADD MENTION IN THE FORECAST WITH LIMITED LIFT. THE DAY
TWO CONVECTIVE OUTLOOK HAS PLACED THE CHANCE OF GENERAL
THUNDERSTORM WAY TO OUR EAST SATURDAY ACROSS EASTERN NORTH
CAROLINA. WENT WITH HIGH TEMPERATURES ON SATURDAY FROM AROUND 80
DEGREES IN THE MOUNTAINS TO THE UPPER 80S IN THE PIEDMONT.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
AS OF 301 PM EDT FRIDAY...
THE FORECAST PERIOD BEGINS WITH A WEAK SURFACE HIGH OVER THE
SOUTHERN APPALACHIANS AND A LEE TROUGH ACROSS THE MID ATLANTIC
COASTAL PIEDMONT. BY SUNDAY AFTERNOON...THE SURFACE HIGH WITHERS
AWAY WITH DIURNAL SHOWERS AND THUNDERSTORMS DEVELOPING ACROSS THE
MOUNTAINS. THESE STORMS ARE EXPECTED TO FADE THROUGH THE EVENING.
MODELS ARE ALSO SHOWING A SHORT WAVES TRACKING EAST BUT NORTH OF THE
AREA SUNDAY MORNING. THIS WAVE AND ASSOCIATED CONVECTION MAY LAY AN
OUTFLOW BOUNDARY ACROSS THE MOUNTAINS TO FURTHER ENHANCE THE
DEVELOPMENT OF AFTERNOON CONVECTION.
SUNDAY NIGHT INTO MONDAY...MODELS ARE MOVING A MESOSCALE COMPLEX
FROM THE OHIO VALLEY TO THE MID ATLANTIC REGION. THE 12Z GFS KEEPS
THIS COMPLEX MOVING EAST ACROSS PENNSYLVANIA MONDAY NIGHT. THE 12Z
NAM/ECM HAS A MORE SOUTHERN TRACK WITH THE COMPLEX TRACKING ACROSS
WEST VIRGINIA MONDAY AND OVER CENTRAL-NORTHERN VIRGINIA MONDAY
AFTERNOON/NIGHT. THIS SOUTHERN TRACK WOULD CLIP THE FORECAST AREA
ALONG AND NORTH OF I64. OUTFLOW BOUNDARIES MAY GENERATE STORMS
ACROSS THE REST OF THE FORECAST AREA LATE MONDAY AFTERNOON/NIGHT.
SUNDAY WILL SEE TEMPERATURES WARMER THAN NORMAL WITH A SOUTHERLY
FLOW AND ABUNDANT SUNSHINE. DESPITE THE COOL START TO THE
MONTH...SUMMER IS NOT OVER FROM A WEATHER STAND POINT. MONDAY WILL
ALSO BE A WARMER THAN NORMAL DAY...ESPECIALLY IF THE MESOSCALE
COMPLEX STAYS WELL TO THE NORTH. SINCE MODELS ARE DELAYING
CONVECTION ACROSS THE SOUTHERN TWO/THIRDS OF THE FORECAST
AREA...WILL CONTINUE TO RUN WITH THE WARMER GUIDANCE.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 100 PM EDT FRIDAY...
UNSETTLED PATTERN DURING THIS PERIOD. SEVERAL SHORTWAVES PIVOT
THROUGH THE REGION TUESDAY AND WEDNESDAY AND THEN MID LEVEL RIDGING
SETS UP FOR THE REST OF THE PERIOD...WITH ADDITIONAL DISTURBANCES
RIDING ALONG THE RIDGE FROM THE NORTHWEST INTO OUR REGION. PLENTY OF
MOISTURE AND INSTABILITY WILL BE PRESENT FOR SCATTERED SHOWERS AND
THUNDERSTORMS EACH DAY. PLACED SLIGHT CHANCE TO CHANCE POPS IN EACH
DAY WITH THE MAX POPS DURING THE AFTERNOON/EVENING HOURS...AND
SLIGHTLY LOWER POPS DURING THE OVERNIGHT HOURS.
TEMPERATURES WILL BE CLOSER TO NORMAL AS 850MB TEMPS RISE FROM +16C
AT THE BEGINNING OF THE PERIOD TO NEAR +20C BY THE WEEKEND. THIS
WILL COORDINATE TO SURFACE HIGH TEMPS NEAR 90 EAST OF THE BLUE RIDGE
AND LOW TO MID 80S FROM THE BLUE RIDGE AND POINTS TO THE WEST.
DEWPOINTS WILL HOLD IN THE MID TO UPPER 60S THROUGH THE PERIOD WHICH
WILL KEEP NIGHT TIME TEMPS ON THE MILD SIDE.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
AS OF 740 PM EDT FRIDAY...
SCATTERED SHOWERS WILL CONTINUE PUSHING SOUTH OF KMKW-KDAN LINE
THROUGH ABOUT 02Z/10PM BEFORE DISSIPATING. AN ISOLATED
THUNDERSTORM CANNOT BE RULED OUT. OVERNIGHT...MAINLY VFR
CONDITIONS AND LIGHT WINDS ARE EXPECTED. PATCHY IFR/MVFR FOG IS
EXPECTED MAINLY IN THE MOUNTAIN AND RIVER VALLEYS...AND THOSE
AREAS THAT RECEIVED RAIN TODAY.
AN SUB VFR CONDITIONS SHOULD IMPROVE QUICKLY TO VFR AFTER SUNRISE
SATURDAY.
AS OF 130 PM EDT FRIDAY...
EXPECT MAINLY VFR INTO THE WEEKEND..WITH HIGH PRESSURE IN PLACE.
HIGH CONFIDENCE IN CEILINGS...VISIBILITIES...AND WINDS DURING THE
PERIOD.
WEATHER PATTERN BECOMES MORE TYPICAL FOR AUGUST BY EARLY NEXT
WEEK. LOW PROBABILITY FOR AFTERNOON AND EVENING
THUNDERSTORMS...THEN FOG IN FAVORED VALLEY LOCATIONS OVERNIGHT.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WP
NEAR TERM...KK
SHORT TERM...RCS
LONG TERM...CF
AVIATION...DS/KK/WP
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
135 PM EDT THU AUG 14 2014
.SYNOPSIS...
A WEAK COLD FRONT WILL REINFORCE THE DRY AIRMASS ON THURSDAY...BUT
COULD BRING A FEW SHOWERS TO THE MOUNTAINS. HIGH PRESSURE WILL
BUILD IN FOR FRIDAY AND SATURDAY. NEXT FRONTAL SYSTEM LOOKS TO
IMPACT US EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 100 PM EDT THURSDAY...
ADJUSTED POPS ALONG THE WESTERN SLOPES THIS AFTERNOON AND EXTENDED
CLOUD COVER FURTHER EAST. MINOR ADJUSTMENTS IN TEMPERATURES AND
DEW POINTS FOR THIS AFTERNOON.
AS OF 930 AM EDT THURSDAY...
MADE SOME MINOR ADJUSTMENTS IN TEMPERATURES AND CLOUD COVER FOR
THIS MORNING INTO THIS AFTERNOON. HRRR AND RNK WRFARW CONTINUE TO
SHOW A FEW SHOWERS WITH THE WEAK COLD FRONT WHICH DROP SOUTHEAST
ACROSS THE REGION. WITH LATEST REGIONAL WRS-88D LOOP SUGGESTING
THAT CONVECTION TO OUR WEST IS DIMINISHING WILL HOLD TO JUST IN
THE WEST. HIGHS THIS AFTERNOON WILL RANGE FROM THE MID 60S IN THE
NORTHWEST TO THE LOWER 80S IN THE SOUTHEAST.
AS OF 710 AM EDT THURSDAY...
UPDATED FORECAST TO ACCOUNT FOR MORE CLOUDS ARRIVING TODAY FROM
THE NW PER IMPULSE NOW OVER NRN KY. THE HIGH-RES MODELS AS WELL AS
THE 06Z GFS/00Z ECMWF ALLOW FOR CLOUDS TO EXPAND EAST INTO THE
FOOTHILLS THIS AFTERNOON...AND BRING ISOLATED/WIDELY SCATTERED
SHOWERS TO THE MTNS OF WV/VA COUNTIES ADJACENT LATER THIS MORNING.
MAY SEE SOME SPRINKLES AS FAR EAST AS THE INTERSTATE 81 CORRIDOR
THIS AFTERNOON. OTHERWISE...NO CHANGES TO THE TEMPS FOR HIGHS.
PREVIOUS VALID DISCUSSION...
HIGHS TODAY WILL BE BELOW NORMAL...STILL THINK MORE SUNSHINE MOST
LOCATIONS...THOUGH POTENTIAL AGAIN FOR THE MTNS STAYING PARTLY
SUNNY- MOSTLY CLOUDY THRU THE DAY. EXPECT HIGHS TO RANGE FROM THE
LOWER TO MID 70S IN THE MOUNTAINS...NEW RIVER VALLEY...TO LOWER TO
MID 80S EAST OF THE BLUE RIDGE AND SRN SHENANDOAH VALLEY.
TONIGHT...ANY SHOWERS OVER THE HIGHER RIDGES OF SE WV WILL
DISSIPATE. STILL UPPER TROUGH CONTINUES TO LINGER OVER THE AREA
WITH ANOTHER SHORTWAVE ROUNDING THE BASE OF THE TROUGH THROUGH WV
LATE. THINK THE CLOUD COVER WILL BE SCATTERED...THOUGH NOT OUT OF
THE QUESTION TO SEE MORE CLOUDS INTO THE MTNS OF WV LATE. LOWS
WILL BE VARYING DEPENDING ON CLOUDS COVER BUT STILL LOOKING AT
COOLER TEMPS...BUT NOT LOOKING AT RECORD LOWS AT THIS
POINT...GIVEN THAT SOME CLOUD COVER MAY AFFECT TEMPS FALLING FAR.
UPPER 40S MTN VALLEYS TO MID TO UPPER 50S EAST OF THE BLUE RIDGE.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 230 AM EDT THURSDAY...
OVERALL MAINLY A CONTINUED TEMPERATURE FORECAST AS THE STRONG 5H TROUGH
PIVOTS EAST ACROSS THE REGION INTO FRIDAY NIGHT BEFORE THE FLOW
TURNS MORE ZONAL OVER THE WEEKEND. THIS WILL ALLOW SURFACE HIGH
PRESSURE TO BUILD IN FRIDAY...WITH THE RIDGE ABOUT OVERHEAD SATURDAY...
BEFORE SLIDING TO THE SE SATURDAY NIGHT. HOWEVER BEFORE THE BETTER
SUBSIDENCE ARRIVES ON SATURDAY...WILL SEE A WEAK MID LEVEL WAVE PIVOT
BY TO THE NORTH BY FRIDAY NIGHT WITH AN ASSOCIATED SURFACE TROUGH
CROSSING THE AREA FRIDAY EVENING. ALTHOUGH MOISTURE LOOKS
LIMITED...DEWPOINTS DO INCREASE ACROSS THE SE LATE FRIDAY AS THE FLOW
BACKS MORE SW OUT EAST. LATEST MODELS SUGGEST COULD BE ISOLATED
SHRA/TSRA FROM NW N CAROLINA EAST INTO SOUTHSIDE VIRGINIA WHERE
GUIDANCE SHOWS AFTERNOON CAPE VALUES OF AROUND 1000 J/KG. SINCE IFFY
GIVEN EXTENT OF DRY AIR ALOFT...WILL ONLY INCLUDE A TOKEN ISOLATED
MENTION EXTREME SE NEAR DANVILLE AND POINTS EAST INTO FRIDAY EVENING
WHILE KEEPING ELSEWHERE DRY. MOISTURE SHOULD PIVOT FAR ENOUGH EAST
WITH THE RESIDUAL FRONT ALONG THE COAST TO KEEP THINGS DRY SATURDAY AND
MAINLY SOUTH OF THE MOISTURE AXIS WITH THE NEXT FRONT TO THE NORTH
SATURDAY NIGHT. DOES APPEAR MORE SHEARED HIGH CLOUDS POSSIBLE SATURDAY
AND THEN WARM ADVECTION MID/HIGH CLOUDS AHEAD OF THE FRONT OVERNIGHT AS
MOISTURE TRANSPORT INCREASES FROM THE WEST/SW.
LARGE DIURNAL RANGE IN TEMPERATURES WILL CONTINUE WITH HIGHS MOSTLY 70S
WEST AND LOW/MID 80S EAST BOTH FRIDAY/SATURDAY WITH LOWS AGAIN QUITE
COOL FRIDAY NIGHT IF SKIES CAN CLEAR. THINK BEST TO LEAN TOWARD THE
WARMER MAV MOS EAST BOTH DAYS GIVEN A BUMP IN 85H TEMPS ALOFT AHEAD OF
THE TROUGH FRIDAY...AND BETTER HEATING OF DRY AIR UNDER BACKING FLOW
SATURDAY. STILL LIKELY TO SEE SOME 40S IN THE VALLEYS FRIDAY NIGHT...
AND 50S ELSEWHERE BEFORE THINGS MOISTEN SATURDAY NIGHT WHEN MOST LOWS
WILL STAY IN THE UPPER 50S TO MID 60S.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 300 PM EDT WEDNESDAY...
THE UPPER LEVEL PATTERN DEAMPLIFIES NEXT WEEK WITH A BROADER UPPER
LEVEL TROUGH OVER THE CONUS YIELDING A STEADY STREAM OF WESTERLIES
ALOFT. THE DOMINANT 500MB PLAYERS LOOK TO BE RIDGING NEAR THE
SOUTHERN TIP OF GREENLAND AND A DEVELOPING RIDGE NEAR 40N/140W...
SOUTH OF THE GULF OF ALASKA AND WEST OF CALIFORNIA. IN BETWEEN...
ACROSS THE LOWER 48...WE ARE LEFT WITH A BROAD TROUGH WITH LITTLE
AMPLITUDE...SENSIBLE WEATHER DETERMINED BY SERIES OF SHORT WAVES
THAT WILL PASS THROUGH THE FLOW DURING THE WEEK. AT THE SURFACE
THE DEPARTING AREA OF HIGH PRESSURE THIS WEEKEND WILL BE REPLACED
BY A NEARLY STATIONARY...W-E ORIENTED WAVY FRONT...THAT WILL SET
UP MID CONUS...AND HELPING TO FOCUS SOME OF THE SENSIBLE WEATHER
ELEMENTS DURING THE WEEK.
DETERMINISTIC MODELS ARE QUITE DIFFERENT IN THE TIMING OF THESE
SHORT WAVES...THE GFS A DAY OR TWO FASTER THAN THE ECMWF AT MOVING
THESE FEATURES EAST BOUND. PREFERENCE IS TO GO WITH THE SLOWER
SOLUTIONS...INTRODUCING SLIGHT CHANCE FOR DIURNAL DEEP CONVECTION
WEST OF THE BLUE RIDGE SUNDAY...THEN AREAWIDE MONDAY AND INTO THE
MIDDLE OF NEXT WEEK PER RETURN OF HIGHER DEWPOINTS AND INSTABILITY
COUPLED WITH ANY SHORT WAVE FEATURES THAT PASS VIA THE PREDOMINANT
WESTERLY FLOW ALOFT.
TEMPERATURES AS A WHOLE FOR NEXT WEEK LOOK LIKE THEY WILL PAN OUT TO
BE NORMAL...A GENERAL LACK OF AMPLIFICATION IN THE WEATHER PATTERN
LEADING TO FEWER TEMPERATURE ANOMALIES.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 135 PM EDT THURSDAY...
VFR WILL PREVAIL THIS AFTERNOON INTO TONIGHT WITH ISOLATED
MVFR SHOWERS/SPRINKLES WITH WEAK FRONT DROPPING SOUTHEAST ACROSS
THE AREA.
BKN VFR CIGS ARE POSSIBLE AS FAR EAST AS THE FOOTHILLS...WITH
SCATTERING OUT OF CLOUDS THIS EVENING INTO TONIGHT. FOG AGAIN A
GOOD BET AT LWB/BCB LATE TONIGHT...BUT CONFIDENCE NOT HIGH IN
BRINGING THEM TOO FAR DOWN...AS NEXT UPSTREAM WAVE MAY BRING
CLOUDS IN LATE TO PREVENT FOG FROM BECOMING DENSE.
VFR CONDITIONS ARE EXPECTED FRIDAY. CAN NOT RULE OUT AN ISOLATED
THUNDERSTORM IN THE SOUTH ALONG THE VIRGINIA AND NORTH CAROLINA
BORDER.
MEDIUM TO HIGH CONFIDENCE IN THE CEILINGS...VISIBILITIES AND WINDS
DURING THE TAF PERIOD.
EXPECT MAINLY VFR THROUGH THE END OF THE WEEK...WITH HIGH PRESSURE
IN PLACE. VALLEY FOG AT LWB/BCB POSSIBLE EACH MORNING.
HIGH PRESSURE MOVES OFF THE COAST BY SUNDAY WITH A FRONT ARRIVING
SUNDAY OR MONDAY WHICH COULD BRING SHOWERS AND STORMS AND SUB VFR
CEILINGS AND VISIBILITIES TO THE REGION.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WP
NEAR TERM...KK/WP
SHORT TERM...JH
LONG TERM...PM
AVIATION...KK/WP
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
940 AM EDT THU AUG 14 2014
.SYNOPSIS...
A WEAK COLD FRONT WILL REINFORCE THE DRY AIRMASS ON THURSDAY...BUT
COULD BRING A FEW SHOWERS TO THE MOUNTAINS. HIGH PRESSURE WILL
BUILD IN FOR FRIDAY AND SATURDAY. NEXT FRONTAL SYSTEM LOOKS TO
IMPACT US EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 AM EDT THURSDAY...
MADE SOME MINOR ADJUSTMENTS IN TEMPERATURES AND CLOUD COVER FOR
THIS MORNING INTO THIS AFTERNOON. HRRR AND RNK WRFARW CONTINUE TO
SHOW A FEW SHOWERS WITH THE WEAK COLD FRONT WHICH DROP SOUTHEAST
ACROSS THE REGION. WITH LATEST REGIONAL WRS-88D LOOP SUGGESTING
THAT CONVECTION TO OUR WEST IS DIMINISHING WILL HOLD TO JUST IN
THE WEST. HIGHS THIS AFTERNOON WILL RANGE FROM THE MID 60S IN THE
NORTHWEST TO THE LOWER 80S IN THE SOUTHEAST.
AS OF 710 AM EDT THURSDAY...
UPDATED FORECAST TO ACCOUNT FOR MORE CLOUDS ARRIVING TODAY FROM
THE NW PER IMPULSE NOW OVER NRN KY. THE HIGH-RES MODELS AS WELL AS
THE 06Z GFS/00Z ECMWF ALLOW FOR CLOUDS TO EXPAND EAST INTO THE
FOOTHILLS THIS AFTERNOON...AND BRING ISOLATED/WIDELY SCATTERED
SHOWERS TO THE MTNS OF WV/VA COUNTIES ADJACENT LATER THIS MORNING.
MAY SEE SOME SPRINKLES AS FAR EAST AS THE INTERSTATE 81 CORRIDOR
THIS AFTERNOON. OTHERWISE...NO CHANGES TO THE TEMPS FOR HIGHS.
PREVIOUS VALID DISCUSSION...
HIGHS TODAY WILL BE BELOW NORMAL...STILL THINK MORE SUNSHINE MOST
LOCATIONS...THOUGH POTENTIAL AGAIN FOR THE MTNS STAYING PARTLY
SUNNY- MOSTLY CLOUDY THRU THE DAY. EXPECT HIGHS TO RANGE FROM THE
LOWER TO MID 70S IN THE MOUNTAINS...NEW RIVER VALLEY...TO LOWER TO
MID 80S EAST OF THE BLUE RIDGE AND SRN SHENANDOAH VALLEY.
TONIGHT...ANY SHOWERS OVER THE HIGHER RIDGES OF SE WV WILL
DISSIPATE. STILL UPPER TROUGH CONTINUES TO LINGER OVER THE AREA
WITH ANOTHER SHORTWAVE ROUNDING THE BASE OF THE TROUGH THROUGH WV
LATE. THINK THE CLOUD COVER WILL BE SCATTERED...THOUGH NOT OUT OF
THE QUESTION TO SEE MORE CLOUDS INTO THE MTNS OF WV LATE. LOWS
WILL BE VARYING DEPENDING ON CLOUDS COVER BUT STILL LOOKING AT
COOLER TEMPS...BUT NOT LOOKING AT RECORD LOWS AT THIS
POINT...GIVEN THAT SOME CLOUD COVER MAY AFFECT TEMPS FALLING FAR.
UPPER 40S MTN VALLEYS TO MID TO UPPER 50S EAST OF THE BLUE RIDGE.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 230 AM EDT THURSDAY...
OVERALL MAINLY A CONTINUED TEMPERATURE FORECAST AS THE STRONG 5H TROUGH
PIVOTS EAST ACROSS THE REGION INTO FRIDAY NIGHT BEFORE THE FLOW
TURNS MORE ZONAL OVER THE WEEKEND. THIS WILL ALLOW SURFACE HIGH
PRESSURE TO BUILD IN FRIDAY...WITH THE RIDGE ABOUT OVERHEAD SATURDAY...
BEFORE SLIDING TO THE SE SATURDAY NIGHT. HOWEVER BEFORE THE BETTER
SUBSIDENCE ARRIVES ON SATURDAY...WILL SEE A WEAK MID LEVEL WAVE PIVOT
BY TO THE NORTH BY FRIDAY NIGHT WITH AN ASSOCIATED SURFACE TROUGH
CROSSING THE AREA FRIDAY EVENING. ALTHOUGH MOISTURE LOOKS
LIMITED...DEWPOINTS DO INCREASE ACROSS THE SE LATE FRIDAY AS THE FLOW
BACKS MORE SW OUT EAST. LATEST MODELS SUGGEST COULD BE ISOLATED
SHRA/TSRA FROM NW N CAROLINA EAST INTO SOUTHSIDE VIRGINIA WHERE
GUIDANCE SHOWS AFTERNOON CAPE VALUES OF AROUND 1000 J/KG. SINCE IFFY
GIVEN EXTENT OF DRY AIR ALOFT...WILL ONLY INCLUDE A TOKEN ISOLATED
MENTION EXTREME SE NEAR DANVILLE AND POINTS EAST INTO FRIDAY EVENING
WHILE KEEPING ELSEWHERE DRY. MOISTURE SHOULD PIVOT FAR ENOUGH EAST
WITH THE RESIDUAL FRONT ALONG THE COAST TO KEEP THINGS DRY SATURDAY AND
MAINLY SOUTH OF THE MOISTURE AXIS WITH THE NEXT FRONT TO THE NORTH
SATURDAY NIGHT. DOES APPEAR MORE SHEARED HIGH CLOUDS POSSIBLE SATURDAY
AND THEN WARM ADVECTION MID/HIGH CLOUDS AHEAD OF THE FRONT OVERNIGHT AS
MOISTURE TRANSPORT INCREASES FROM THE WEST/SW.
LARGE DIURNAL RANGE IN TEMPERATURES WILL CONTINUE WITH HIGHS MOSTLY 70S
WEST AND LOW/MID 80S EAST BOTH FRIDAY/SATURDAY WITH LOWS AGAIN QUITE
COOL FRIDAY NIGHT IF SKIES CAN CLEAR. THINK BEST TO LEAN TOWARD THE
WARMER MAV MOS EAST BOTH DAYS GIVEN A BUMP IN 85H TEMPS ALOFT AHEAD OF
THE TROUGH FRIDAY...AND BETTER HEATING OF DRY AIR UNDER BACKING FLOW
SATURDAY. STILL LIKELY TO SEE SOME 40S IN THE VALLEYS FRIDAY NIGHT...
AND 50S ELSEWHERE BEFORE THINGS MOISTEN SATURDAY NIGHT WHEN MOST LOWS
WILL STAY IN THE UPPER 50S TO MID 60S.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 300 PM EDT WEDNESDAY...
THE UPPER LEVEL PATTERN DEAMPLIFIES NEXT WEEK WITH A BROADER UPPER
LEVEL TROUGH OVER THE CONUS YIELDING A STEADY STREAM OF WESTERLIES
ALOFT. THE DOMINANT 500MB PLAYERS LOOK TO BE RIDGING NEAR THE
SOUTHERN TIP OF GREENLAND AND A DEVELOPING RIDGE NEAR 40N/140W...
SOUTH OF THE GULF OF ALASKA AND WEST OF CALIFORNIA. IN BETWEEN...
ACROSS THE LOWER 48...WE ARE LEFT WITH A BROAD TROUGH WITH LITTLE
AMPLITUDE...SENSIBLE WEATHER DETERMINED BY SERIES OF SHORT WAVES
THAT WILL PASS THROUGH THE FLOW DURING THE WEEK. AT THE SURFACE
THE DEPARTING AREA OF HIGH PRESSURE THIS WEEKEND WILL BE REPLACED
BY A NEARLY STATIONARY...W-E ORIENTED WAVY FRONT...THAT WILL SET
UP MID CONUS...AND HELPING TO FOCUS SOME OF THE SENSIBLE WEATHER
ELEMENTS DURING THE WEEK.
DETERMINISTIC MODELS ARE QUITE DIFFERENT IN THE TIMING OF THESE
SHORT WAVES...THE GFS A DAY OR TWO FASTER THAN THE ECMWF AT MOVING
THESE FEATURES EAST BOUND. PREFERENCE IS TO GO WITH THE SLOWER
SOLUTIONS...INTRODUCING SLIGHT CHANCE FOR DIURNAL DEEP CONVECTION
WEST OF THE BLUE RIDGE SUNDAY...THEN AREAWIDE MONDAY AND INTO THE
MIDDLE OF NEXT WEEK PER RETURN OF HIGHER DEWPOINTS AND INSTABILITY
COUPLED WITH ANY SHORT WAVE FEATURES THAT PASS VIA THE PREDOMINANT
WESTERLY FLOW ALOFT.
TEMPERATURES AS A WHOLE FOR NEXT WEEK LOOK LIKE THEY WILL PAN OUT TO
BE NORMAL...A GENERAL LACK OF AMPLIFICATION IN THE WEATHER PATTERN
LEADING TO FEWER TEMPERATURE ANOMALIES.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
AS OF 725 AM EDT THURSDAY...
LOW CIGS STILL STUCK IN BLF THIS MORNING. EXPECT THIS TO ERODE TO
SCATTERED AFTER 14Z...BUT SEEING MORE CLOUDS UPSTREAM ASSOCIATED
WITH EMBEDDED SHORTWAVE THAT WILL PUSH IN BKN/OVC CIGS TO BLF/LWB
BY MIDDAY...ALTHOUGH CIGS SHOULD BE ABOVE 3KFT BY THEN. THE FOG AT
A FEW LOCATIONS WILL BE GONE BY 13Z.
VFR IS EXPECTED...AND WILL SEE A FEW SHOWERS/SPRINKLES CLOSE BY TO
LWB/BLF...BUT NOT ENOUGH OF A COVERAGE AREA TO INCLUDE IN THE
TAFS.
WILL SEE BKN VFR CIGS AS FAR EAST AS THE FOOTHILLS...WITH
SCATTERING OUT OF CLOUDS THIS EVENING. FOG AGAIN A GOOD BET AT
LWB/BCB LATE TONIGHT...BUT CONFIDENCE NOT HIGH IN BRINGING THEM
TOO FAR DOWN...AS NEXT UPSTREAM WAVE MAY BRING CLOUDS IN LATE TO
PREVENT FOG FROM BECOMING DENSE.
EXPECT MAINLY VFR THROUGH THE END OF THE WEEK...WITH HIGH PRESSURE
IN PLACE. VALLEY FOG AT LWB/BCB POSSIBLE EACH MORNING.
HIGH PRESSURE MOVES OFF THE COAST BY SUNDAY WITH A FRONT ARRIVING
SUNDAY OR MONDAY WHICH COULD BRING SHOWERS AND STORMS AND SUB VFR
CEILINGS AND VISIBILITIES TO THE REGION.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WP
NEAR TERM...KK/WP
SHORT TERM...JH
LONG TERM...PM
AVIATION...AMS/KK/WP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
618 PM CDT FRI AUG 15 2014
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 341 PM CDT FRI AUG 15 2014
AT 3 PM...A BAND OF SHOWERS EXTENDED FROM SOUTH-CENTRAL IOWA
SOUTHEAST INTO SOUTHEAST IOWA. THIS IS ASSOCIATED WITH MODERATE TO
STRONG 900 TO 500 MB FRONTOGENETIC FORCING AND WEAK TO MODERATE
305K ISENTROPIC LIFT.
FOR TONIGHT...THE MESO AND DETERMINISTIC MODELS ARE IN GOOD
AGREEMENT THAT THE TROUGH OF LOW PRESSURE...CURRENTLY OVER EASTERN
SOUTH DAKOTA AND EASTERN NEBRASKA WILL MOVE EAST AND SOUTHEAST
THROUGH IOWA. THE MESO MODELS SHOW THAT THE MODERATE TO STRONG 900
TO 500 MB FRONTOGENESIS WILL REMAIN SOUTHWEST OF THE AREA THIS
EVENING...AND SOUTH OF THE AREA OVERNIGHT. AS A LOW DEVELOPS OVER
IOWA OVERNIGHT...THE 305K ISENTROPIC LIFT INCREASES DRAMATICALLY
ACROSS SOUTH-CENTRAL IOWA. THIS WILL LIKELY KEEP A MAJORITY OF
THE SHOWERS AND THUNDERSTORMS SOUTH OF THE AREA. HOWEVER WITH THE
NAM SOLUTIONS SUGGESTING A SLIGHTLY FURTHER NORTH TRACK OF THIS
SYSTEM KEPT A SLIGHT CHANCE OF PRECIPITATION IN FLOYD...
CHICKASAW...FAYETTE...AND CLAYTON COUNTIES IN NORTHEAST IOWA AND
GRANT COUNTY IN SOUTHWEST WISCONSIN BETWEEN 2 AM AND 10 AM
SATURDAY.
ANOTHER ISSUE FOR EARLY SATURDAY MORNING IS THE POTENTIAL FOR
AREAS OF FOG TO DEVELOP. BOTH THE NAM AND GFS BUFKIT SOUNDINGS
SHOW THAT THERE WILL BE A DRAMATIC INCREASE IN THE MOISTURE BELOW
925 MB AFTER 3 AM. THE WINDS IN THIS LAYER ARE LESS THAN 10 KNOTS
WHICH WOULD BE CONDUCIVE FOR THE DEVELOPMENT OF FOG. THE NUMERICAL
GUIDANCE SUGGESTS THAT THIS FOG COULD BECOME DENSE. ONE THING THAT
MIGHT DETER THE DENSE FOG DEVELOPMENT IS THE 10 TO 15 KNOT WINDS
BETWEEN 950 AND 900 MB. FOR THE TIME BEING...JUST ADDED AREAS OF
FOG TO THE GRIDS.
ON SATURDAY AFTERNOON...THE MODELS CONTINUE TO SHOW THAT A
CANADIAN COLD FRONT WILL MOVE SOUTH INTO NORTH-CENTRAL WISCONSIN
DURING THE MID TO LATE AFTERNOON. ML CAPES AHEAD OF THIS FRONT
CLIMB INTO THE 1000 TO 1500 J/KG RANGE. HOWEVER BOTH THE 0-3 KM
AND 0-6 KM SHEAR IS NOT THAT FAVORABLE FOR THE DEVELOPMENT OF
SEVERE WEATHER.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 341 PM CDT FRI AUG 15 2014
ON SATURDAY EVENING...THE ML CAPES ALONG AND AHEAD OF COLD FRONT
MOVING THROUGH THE INTERSTATE 90 AND 94 CORRIDORS QUICKLY
DECREASES WITH THE LOSS OF DIURNAL HEATING. AS THIS OCCURS...THE
SHOWER AND THUNDERSTORM ACTIVITY WILL BECOME ISOLATED.
ON SUNDAY AND SUNDAY NIGHT...A CANADIAN HIGH PRESSURE WILL BRING
DRIER AIR INTO THE REGIONS. ORIGINALLY THE NAM KEPT THE DEW POINTS
IN THE LOWER AND MID 60S...BUT IT HAS NOW SHIFTED TOWARD THE DRIER
GFS AND ECMWF SOLUTIONS OF YESTERDAY. THE COMBINATION OF LIGHT
WINDS AND DEW POINTS IN THE MID AND UPPER 40S WILL ALLOW
TEMPERATURES TO ONCE AGAIN DROP INTO THE MID AND UPPER 40S ON
MONDAY MORNING. DUE TO THIS...WENT COLDER THAN THE SUPERBLEND.
FROM MONDAY AFTERNOON INTO TUESDAY NIGHT...THE 15.12Z MODELS
CONTINUE TO AGREE WITH PREVIOUS MODEL RUNS THAT A SHORT WAVE
TROUGH /THIS SYSTEM IS CURRENTLY LOCATED OVER THE PACIFIC
NORTHWEST/ WILL MOVE THROUGH THE REGION. WITH MODERATE 850 MB
MOISTURE TRANSPORT AHEAD OF THIS SYSTEM...THIS LOOKS TO BE OUR
BEST CHANCE FOR WIDESPREAD RAIN ACROSS THE AREA.
FROM WEDNESDAY INTO FRIDAY...THE MODELS CONTINUE TO STRUGGLE WITH
THE TIMING OF SHORT WAVE TROUGH MOVING THROUGH THE REGION. IN
ADDITION...THEY KEEP TRYING TO DEVELOP A TROUGH OVER THE WESTERN
UNITED STATES WHICH WOULD PRODUCE ZONAL OR SOUTHWEST FLOW ACROSS
OUR AREA. HOWEVER WITH THE ANOMALOUS WARM WATER LOCATED OFF THE
WEST COAST OF CANADA /LIKE MUCH OF LAST WINTER/...THE PATTERN THAT
THE MODELS ARE TRYING TO TREND TOWARD IS NOT THAT FAVORABLE...SO A
BIT LEARY OF THE GFS AND ECMWF SOLUTIONS DURING THIS TIME FRAME.
THIS INCLUDES THE VERY WARM TEMPERATURES THAT THESE MODELS ARE
INDICATING FOR THE END OF NEXT WEEK. A MORE FAVORABLE PATTERN
WOULD BE FOR A TROUGH OVER THE GREAT LAKES AND OHIO VALLEYS WHICH
WOULD KEEP US IN A NORTHWEST FLOW ALOFT.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 618 PM CDT FRI AUG 15 2014
THE MAIN FORECAST CONCERN IS WHETHER FOG IS GOING TO FORM
OVERNIGHT AT BOTH TAF SITES. AS THE NIGHT PROGRESSES...AN AREA OF
LOW PRESSURE IS EXPECTED TO FORM OVER SOUTHEAST NEBRASKA OR
SOUTHWEST IOWA. THE GRADIENT NORTH OF THIS LOW IS EXPECTED TO
BECOME LIGHT AS A SURFACE RIDGE EXTENDS INTO THE AREA FROM HIGH
PRESSURE SITTING OVER THE OHIO RIVER VALLEY. THIS WILL SET UP A
FAVORABLE LOW LEVEL WIND FIELD WITH VERY LIGHT FLOW EXPECTED. BOTH
THE 15.18Z NAM AND 15.21Z RAP SHOW THAT SATURATION WILL OCCUR AT
THE SURFACE WHICH WILL ALSO BE FAVORABLE FOR FOG FORMATION. OF
CONCERN THOUGH IS THE HIGH CLOUDS CURRENTLY OVER THE AREA AND
WHETHER THESE WILL DISSIPATE OR REMAIN IN PLACE AS THE SURFACE LOW
FORMS. ALSO...BOTH MODELS SHOW A LAYER OF HIGHER WINDS JUST ABOVE
THE SURFACE WITH SPEEDS OF 10 TO 20 KNOTS. THE NAM IS DEEPER WITH
THIS LAYER THAN THE RAP...BUT THESE WINDS AND THE HIGHER CLOUDS
MAY INHIBIT THE FOG FORMATION WITH A STRATUS LAYER MORE OF A
POSSIBILITY. CONFIDENCE IN THE EVENTUAL OUTCOME REMAINS LOW AND
HAVE OPTED TO CONTINUE THE TREND OF SHOWING MVFR VISIBILITIES
DEVELOPING...BUT DID AT LEAST ADD IN A SCATTERED LAYER OF SUB 1000
FOOT STRATUS TO SHOW THIS POSSIBILITY. ONCE THE FOG AND STRATUS
LIFT SATURDAY MORNING...VFR CONDITIONS EXPECTED FOR THE REST OF
THE DAY. SHOULD SEE SOME SCATTERED CUMULUS AHEAD OF AN APPROACHING
COLD FRONT THAT IS NOT EXPECTED TO MOVE TROUGH UNTIL SATURDAY
EVENING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...04
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1141 AM MDT THU AUG 14 2014
.UPDATE...
ISSUED AT 900 AM MDT THU AUG 14 2014
AFTER CHECKING THE 12Z MODEL RUNS AND LATEST SATELLITE...RADAR...
AND SURFACE OBSERVATIONS HAVE MADE SOME ADJUSTMENTS TO THE
FORECAST TODAY. TEMPERATURES ARE STRUGGLING TO WARM OVER MOST OF
THE FORECAST AREA DUE TO THICK CLOUD COVER AND RAIN SHOWERS.
CHEYENNE IS CURRENTLY 70 DEGREES AND NOT LIKELY TO WARM TO MUCH
FURTHER BEFORE SHOWERS DEVELOP. THIS WILL BE SIMILAR TO MUCH OF
THE PLAINS IN SOUTHEAST WYOMING. INTO THE NEBRASKA PANHANDLE...
PLACES LIKE SIDNEY AND ALLIANCE MAY APPROACH 90 DEGREES BEFORE
THICKER CLOUDS MOVE IN...OTHERWISE TEMPERATURES SHOULD GENERALLY
ONLY HIT 80-85 DEGREES TODAY IN THE PANHANDLE.
LOOKING AT WATER VAPOR AND VISIBLE SATELLITE...THE PLACEMENT OF
SHORTWAVE ENERGY IS NOT WHAT THE MODELS WERE SHOWING YESTERDAY.
YESTERDAY MODELS WERE SHOWING ONE SHORTWAVE MOVING ACROSS SOUTHEAST
WYOMING...BUT IN FACT THERE ARE TWO SEPARATE CIRCULATIONS. ONE
OVER CENTRAL WYOMING WHICH IS LIFTING NORTH AND ONE OVER WESTERN
COLORADO MOVING EAST. THEREFORE THE DYNAMIC SETUP IS NOT AS
FAVORABLE FOR SOUTHEAST WYOMING AS EARLIER EXPECTED. THIS MEANS
THE THREAT FOR HEAVY RAIN IS MINIMAL TODAY. ALSO THE 12Z MODELS
ARE SHOWING LESS INSTABILITY AND CAPE TODAY WHICH ALSO SUGGESTS
MINIMAL HEAVY RAIN THREAT. SO FOR THE REST OF TODAY SHOULD SEE
SHOWERS SPREAD EAST INTO THE PLAINS WITH ISOLATED THUNDERSTORMS.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 350 AM MDT THU AUG 14 2014
LATEST WATER VAPOR IMAGERY SHOWING THE UPPER LEVEL LOW PUSHING
INTO NORTHWESTERN COLORADO THIS MORNING. LOOKS TO BE HANDLED WELL
BY THE ECMWF. LATEST MOSAIC RADAR SHOWING SHOWERS WIDESPREAD OVER
RIVERTONS CWFA WITH SOME SHOWER ACTIVITY OVER CARBON COUNTY.
MESOWEST OBSERVATIONS REPORTING MEASURABLE RAINFALL OVER THE SNOWY
AND SIERRA MADRE RANGES AS WELL AS THE NORTH LARAMIE RANGE.
FOR TODAY...WE SHOULD SEE AN INCREASE IN SHOWERS AND THUNDERSTORMS
AS THE MORNING PROGRESSES. UPPER LOW MOVES OVER CASPER BY 00Z WITH
FAIRLY WIDESPREAD SHOWERS OVER OUR SOUTHERN ZONES. PWATS FOR
RAWLINS FROM THE NAM UP NEAR 1.2 INCHES AT 18Z...NEAR 1.4 INCHES
HERE AT CHEYENNE BY 00Z AND NEAR 1.7 INCHES AT CHADRON BY 06Z THIS
EVENING. LATEST HRRR FORECAST AND FORECAST IR IMAGERY SHOWING
SHOWERS AND THUNDERSTORMS EAST OF THE LARAMIE RANGE BREAKING OUT
HERE AT CHEYENNE AROUND 15Z AND OUT IN THE PANHANDLE AFTER 18Z.
FORECAST STORM MOTIONS A LITTLE HIGHER THAN PREVIOUSLY FORECAST
WITH NAM SHOWING 10-15KTS. GIVEN THAT STORM MOTIONS ARE
HIGHER...HAVE DECIDED TO HOLD OFF ON A FLASH FLOOD WATCH. WOULD
THINK WE COULD SEE SOME FLASH FLOOD WARNING POSSIBLE THIS
AFTERNOON...BUT THESE WILL BE FOR TRAINING STORMS AND NOT FOR SLOW
MOVING STORMS. MAY TAKE ANOTHER LOOK LATER THIS MORNING WHEN THE
06Z MODEL DATA COMES OUT.
LOOKS LIKE SHOWERS AND THUNDERSTORMS WILL COME TO AN END BY 06Z
TONIGHT AS THE ECMWF SHOWS SHORTWAVE MOVING INTO CENTRAL SOUTH
DAKOTA AND CENTRAL NEBRASKA. STILL SOME POSITIVE VORTICITY
ADVECTION OVER THE NORTHERN PANHANDLE FRIDAY MORNING...SO DID KEEP
SOME SLIGHT CHANCE POPS GOING OUT THAT WAY FOR FRIDAY MORNING AND
AFTERNOON.
UPPER RIDGE BUILDS BACK INTO THE AREA FRIDAY NIGHT INTO SATURDAY AS
SHORTWAVE BEGINS TO MOVE SOUTHEAST INTO EASTERN KANSAS. 700MB
WINDS PICKING UP TO 20-25KTS ACROSS THE CWFA MAY LEAD TO
HEIGHTENED FIRE WEATHER CONCERNS SATURDAY...MORE LIKELY THOUGH ON
SUNDAY.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 350 AM MDT THU AUG 14 2014
SATURDAY NIGHT...DRY PERIOD WITH LIMITED LOW AND MID LEVEL MOISTURE
AND DOWNSLOPE WEST WINDS.
SUNDAY...NEXT SHORTWAVE TROUGH ALOFT MOVES ACROSS EASTERN MONTANA
AND EASTERN WYOMING WITH AN ASSOCIATED SURFACE TROUGH. ISOLATED
SHOWERS AND THUNDERSTORMS EXPECTED...NORTH OF A DOUGLAS TO
SCOTTSBLUFF LINE.
MONDAY...RELATIVELY DRY NORTHWEST FLOW ALOFT PREVAILS...THOUGH LOOKS
LIKE ENOUGH LOW AND MID LEVEL MOISTURE FOR ISOLATED LATE DAY SHOWERS
AND THUNDERSTORMS FROM WHEATLAND TO ALLIANCE.
TUESDAY...SLIGHT DECREASE IN LOW AND MID LEVEL MOISTURE...ACTING AS
THE FUEL FOR THUNDERSTORMS...THUS ONLY ISOLATED STORMS AT
BEST...NORTH OF A RAWLINS TO SCOTTSBLUFF LINE.
WEDNESDAY...DRY WEST WINDS PREVAIL IN THE LOW AND MID
LEVELS...EFFECTIVELY DRYING OUT THE ATMOSPHERE EVEN MORE...AND
PRODUCING A MILD LATE AUGUST DAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY MORNING)
ISSUED AT 1131 AM MDT THU AUG 14 2014
SCATTERED LIGHT SHOWERS CAN BE EXPECTED FOR ALL TERMINALS DURING
THE AFTN AND EVE HOURS. A FEW LIGHTNING STRIKES ARE POSSIBLE OVER
THE WESTERN NE PANHANDLE AFTER 21Z WHERE INSTABILITY IS HIGHER DUE
TO MORNING SUNSHINE. EXPECT THAT IMPACTS FROM THIS RAIN EVENT WILL
BE LOWER THAN EARLIER THOUGHT...SO THE GENERAL RULE SHOULD BE VFR
CONDITIONS THROUGH THE TAF PERIOD. LOW CLOUDS AND MVFR CIGS MAY
HANG AROUND RWL FOR A FEW MORE HOURS...BUT CONDITIONS ARE LIKELY
TO IMPOVE THERE SOON.
&&
.FIRE WEATHER...
ISSUED AT 350 AM MDT THU AUG 14 2014
WIDESPREAD WETTING RAINS TODAY BEGINNING OVER CARBON COUNTY...THEN
SPREADING EAST. THIS IS DUE TO A UPPER LEVEL LOW PRESSURE SYSTEM
MOVING SLOWLY NORTHEAST AND INTERACTING WITH MONSOONAL MOISTURE
OVER THE AREA. THIS LOW WILL KEEP UNSETTLED WEATHER OVER SOUTHEAST
WYOMING AND NEBRASKA PANHANDLE THROUGH FRIDAY AFTERNOON AS THE LOW
SLOWLY MOVES OUT OF THE AREA. DRIER CONDITIONS AFTER FRIDAY
AFTERNOON AS WESTERLY WINDS RETURN. AFTERNOON HUMIDITIES SATURDAY
AND SUNDAY WILL LOOK TO BECOME CRITICAL WEST OF THE LARAMIE RANGE.
GUSTY WESTERLY WINDS AS WELL BOTH AFTERNOONS THAT COULD REACH
CRITICAL CRITERIA.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...SML
SHORT TERM...CLAYCOMB
LONG TERM...RUBIN
AVIATION...HAMMER
FIRE WEATHER...CLAYCOMB
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
904 AM MDT THU AUG 14 2014
.UPDATE...
ISSUED AT 900 AM MDT THU AUG 14 2014
AFTER CHECKING THE 12Z MODEL RUNS AND LATEST SATELLITE...RADAR...
AND SURFACE OBSERVATIONS HAVE MADE SOME ADJUSTMENTS TO THE
FORECAST TODAY. TEMPERATURES ARE STRUGGLING TO WARM OVER MOST OF
THE FORECAST AREA DUE TO THICK CLOUD COVER AND RAIN SHOWERS.
CHEYENNE IS CURRENTLY 70 DEGREES AND NOT LIKELY TO WARM TO MUCH
FURTHER BEFORE SHOWERS DEVELOP. THIS WILL BE SIMILAR TO MUCH OF
THE PLAINS IN SOUTHEAST WYOMING. INTO THE NEBRASKA PANHANDLE...
PLACES LIKE SIDNEY AND ALLIANCE MAY APPROACH 90 DEGREES BEFORE
THICKER CLOUDS MOVE IN...OTHERWISE TEMPERATURES SHOULD GENERALLY
ONLY HIT 80-85 DEGREES TODAY IN THE PANHANDLE.
LOOKING AT WATER VAPOR AND VISIBLE SATELLITE...THE PLACEMENT OF
SHORTWAVE ENERGY IS NOT WHAT THE MODELS WERE SHOWING YESTERDAY.
YESTERDAY MODELS WERE SHOWING ONE SHORTWAVE MOVING ACROSS SOUTHEAST
WYOMING...BUT IN FACT THERE ARE TWO SEPARATE CIRCULATIONS. ONE
OVER CENTRAL WYOMING WHICH IS LIFTING NORTH AND ONE OVER WESTERN
COLORADO MOVING EAST. THEREFORE THE DYNAMIC SETUP IS NOT AS
FAVORABLE FOR SOUTHEAST WYOMING AS EARLIER EXPECTED. THIS MEANS
THE THREAT FOR HEAVY RAIN IS MINIMAL TODAY. ALSO THE 12Z MODELS
ARE SHOWING LESS INSTABILITY AND CAPE TODAY WHICH ALSO SUGGESTS
MINIMAL HEAVY RAIN THREAT. SO FOR THE REST OF TODAY SHOULD SEE
SHOWERS SPREAD EAST INTO THE PLAINS WITH ISOLATED THUNDERSTORMS.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 350 AM MDT THU AUG 14 2014
LATEST WATER VAPOR IMAGERY SHOWING THE UPPER LEVEL LOW PUSHING
INTO NORTHWESTERN COLORADO THIS MORNING. LOOKS TO BE HANDLED WELL
BY THE ECMWF. LATEST MOSAIC RADAR SHOWING SHOWERS WIDESPREAD OVER
RIVERTONS CWFA WITH SOME SHOWER ACTIVITY OVER CARBON COUNTY.
MESOWEST OBSERVATIONS REPORTING MEASURABLE RAINFALL OVER THE SNOWY
AND SIERRA MADRE RANGES AS WELL AS THE NORTH LARAMIE RANGE.
FOR TODAY...WE SHOULD SEE AN INCREASE IN SHOWERS AND THUNDERSTORMS
AS THE MORNING PROGRESSES. UPPER LOW MOVES OVER CASPER BY 00Z WITH
FAIRLY WIDESPREAD SHOWERS OVER OUR SOUTHERN ZONES. PWATS FOR
RAWLINS FROM THE NAM UP NEAR 1.2 INCHES AT 18Z...NEAR 1.4 INCHES
HERE AT CHEYENNE BY 00Z AND NEAR 1.7 INCHES AT CHADRON BY 06Z THIS
EVENING. LATEST HRRR FORECAST AND FORECAST IR IMAGERY SHOWING
SHOWERS AND THUNDERSTORMS EAST OF THE LARAMIE RANGE BREAKING OUT
HERE AT CHEYENNE AROUND 15Z AND OUT IN THE PANHANDLE AFTER 18Z.
FORECAST STORM MOTIONS A LITTLE HIGHER THAN PREVIOUSLY FORECAST
WITH NAM SHOWING 10-15KTS. GIVEN THAT STORM MOTIONS ARE
HIGHER...HAVE DECIDED TO HOLD OFF ON A FLASH FLOOD WATCH. WOULD
THINK WE COULD SEE SOME FLASH FLOOD WARNING POSSIBLE THIS
AFTERNOON...BUT THESE WILL BE FOR TRAINING STORMS AND NOT FOR SLOW
MOVING STORMS. MAY TAKE ANOTHER LOOK LATER THIS MORNING WHEN THE
06Z MODEL DATA COMES OUT.
LOOKS LIKE SHOWERS AND THUNDERSTORMS WILL COME TO AN END BY 06Z
TONIGHT AS THE ECMWF SHOWS SHORTWAVE MOVING INTO CENTRAL SOUTH
DAKOTA AND CENTRAL NEBRASKA. STILL SOME POSITIVE VORTICITY
ADVECTION OVER THE NORTHERN PANHANDLE FRIDAY MORNING...SO DID KEEP
SOME SLIGHT CHANCE POPS GOING OUT THAT WAY FOR FRIDAY MORNING AND
AFTERNOON.
UPPER RIDGE BUILDS BACK INTO THE AREA FRIDAY NIGHT INTO SATURDAY AS
SHORTWAVE BEGINS TO MOVE SOUTHEAST INTO EASTERN KANSAS. 700MB
WINDS PICKING UP TO 20-25KTS ACROSS THE CWFA MAY LEAD TO
HEIGHTENED FIRE WEATHER CONCERNS SATURDAY...MORE LIKELY THOUGH ON
SUNDAY.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 350 AM MDT THU AUG 14 2014
SATURDAY NIGHT...DRY PERIOD WITH LIMITED LOW AND MID LEVEL MOISTURE
AND DOWNSLOPE WEST WINDS.
SUNDAY...NEXT SHORTWAVE TROUGH ALOFT MOVES ACROSS EASTERN MONTANA
AND EASTERN WYOMING WITH AN ASSOCIATED SURFACE TROUGH. ISOLATED
SHOWERS AND THUNDERSTORMS EXPECTED...NORTH OF A DOUGLAS TO
SCOTTSBLUFF LINE.
MONDAY...RELATIVELY DRY NORTHWEST FLOW ALOFT PREVAILS...THOUGH LOOKS
LIKE ENOUGH LOW AND MID LEVEL MOISTURE FOR ISOLATED LATE DAY SHOWERS
AND THUNDERSTORMS FROM WHEATLAND TO ALLIANCE.
TUESDAY...SLIGHT DECREASE IN LOW AND MID LEVEL MOISTURE...ACTING AS
THE FUEL FOR THUNDERSTORMS...THUS ONLY ISOLATED STORMS AT
BEST...NORTH OF A RAWLINS TO SCOTTSBLUFF LINE.
WEDNESDAY...DRY WEST WINDS PREVAIL IN THE LOW AND MID
LEVELS...EFFECTIVELY DRYING OUT THE ATMOSPHERE EVEN MORE...AND
PRODUCING A MILD LATE AUGUST DAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 521 AM MDT THU AUG 14 2014
EXPECT INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH
THE MORNING HOURS FOR KRWL AND KLAR WITH SHOWERS SPREADING EAST
THIS AFTERNOON. SOME OF THE STRONGER STORMS WILL PRODUCE HEAVY
RAINFALL THAT COULD REDUCE FLIGHT CONDITIONS TO IFR CONDITIONS
THROUGH THE AFTERNOON HOURS. SHOWERS ENDING LATE THIS EVENING FROM
WEST TO EAST.
&&
.FIRE WEATHER...
ISSUED AT 350 AM MDT THU AUG 14 2014
WIDESPREAD WETTING RAINS TODAY BEGINNING OVER CARBON COUNTY...THEN
SPREADING EAST. THIS IS DUE TO A UPPER LEVEL LOW PRESSURE SYSTEM
MOVING SLOWLY NORTHEAST AND INTERACTING WITH MONSOONAL MOISTURE
OVER THE AREA. THIS LOW WILL KEEP UNSETTLED WEATHER OVER SOUTHEAST
WYOMING AND NEBRASKA PANHANDLE THROUGH FRIDAY AFTERNOON AS THE LOW
SLOWLY MOVES OUT OF THE AREA. DRIER CONDITIONS AFTER FRIDAY
AFTERNOON AS WESTERLY WINDS RETURN. AFTERNOON HUMIDITIES SATURDAY
AND SUNDAY WILL LOOK TO BECOME CRITICAL WEST OF THE LARAMIE RANGE.
GUSTY WESTERLY WINDS AS WELL BOTH AFTERNOONS THAT COULD REACH
CRITICAL CRITERIA.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...SML
SHORT TERM...CLAYCOMB
LONG TERM...RUBIN
AVIATION...CLAYCOMB
FIRE WEATHER...CLAYCOMB
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
525 AM MDT THU AUG 14 2014
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 350 AM MDT THU AUG 14 2014
LATEST WATER VAPOR IMAGERY SHOWING THE UPPER LEVEL LOW PUSHING
INTO NORTHWESTERN COLORADO THIS MORNING. LOOKS TO BE HANDLED WELL
BY THE ECMWF. LATEST MOSAIC RADAR SHOWING SHOWERS WIDESPREAD OVER
RIVERTONS CWFA WITH SOME SHOWER ACTIVITY OVER CARBON COUNTY.
MESOWEST OBSERVATIONS REPORTING MEASURABLE RAINFALL OVER THE SNOWY
AND SIERRA MADRE RANGES AS WELL AS THE NORTH LARAMIE RANGE.
FOR TODAY...WE SHOULD SEE AN INCREASE IN SHOWERS AND THUNDERSTORMS
AS THE MORNING PROGRESSES. UPPER LOW MOVES OVER CASPER BY 00Z WITH
FAIRLY WIDESPREAD SHOWERS OVER OUR SOUTHERN ZONES. PWATS FOR
RAWLINS FROM THE NAM UP NEAR 1.2 INCHES AT 18Z...NEAR 1.4 INCHES
HERE AT CHEYENNE BY 00Z AND NEAR 1.7 INCHES AT CHADRON BY 06Z THIS
EVENING. LATEST HRRR FORECAST AND FORECAST IR IMAGERY SHOWING
SHOWERS AND THUNDERSTORMS EAST OF THE LARAMIE RANGE BREAKING OUT
HERE AT CHEYENNE AROUND 15Z AND OUT IN THE PANHANDLE AFTER 18Z.
FORECAST STORM MOTIONS A LITTLE HIGHER THAN PREVIOUSLY FORECAST
WITH NAM SHOWING 10-15KTS. GIVEN THAT STORM MOTIONS ARE
HIGHER...HAVE DECIDED TO HOLD OFF ON A FLASH FLOOD WATCH. WOULD
THINK WE COULD SEE SOME FLASH FLOOD WARNING POSSIBLE THIS
AFTERNOON...BUT THESE WILL BE FOR TRAINING STORMS AND NOT FOR SLOW
MOVING STORMS. MAY TAKE ANOTHER LOOK LATER THIS MORNING WHEN THE
06Z MODEL DATA COMES OUT.
LOOKS LIKE SHOWERS AND THUNDERSTORMS WILL COME TO AN END BY 06Z
TONIGHT AS THE ECMWF SHOWS SHORTWAVE MOVING INTO CENTRAL SOUTH
DAKOTA AND CENTRAL NEBRASKA. STILL SOME POSITIVE VORTICITY
ADVECTION OVER THE NORTHERN PANHANDLE FRIDAY MORNING...SO DID KEEP
SOME SLIGHT CHANCE POPS GOING OUT THAT WAY FOR FRIDAY MORNING AND
AFTERNOON.
UPPER RIDGE BUILDS BACK INTO THE AREA FRIDAY NIGHT INTO SATURDAY AS
SHORTWAVE BEGINS TO MOVE SOUTHEAST INTO EASTERN KANSAS. 700MB
WINDS PICKING UP TO 20-25KTS ACROSS THE CWFA MAY LEAD TO
HEIGHTENED FIRE WEATHER CONCERNS SATURDAY...MORE LIKELY THOUGH ON
SUNDAY.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 350 AM MDT THU AUG 14 2014
SATURDAY NIGHT...DRY PERIOD WITH LIMITED LOW AND MID LEVEL MOISTURE
AND DOWNSLOPE WEST WINDS.
SUNDAY...NEXT SHORTWAVE TROUGH ALOFT MOVES ACROSS EASTERN MONTANA
AND EASTERN WYOMING WITH AN ASSOCIATED SURFACE TROUGH. ISOLATED
SHOWERS AND THUNDERSTORMS EXPECTED...NORTH OF A DOUGLAS TO
SCOTTSBLUFF LINE.
MONDAY...RELATIVELY DRY NORTHWEST FLOW ALOFT PREVAILS...THOUGH LOOKS
LIKE ENOUGH LOW AND MID LEVEL MOISTURE FOR ISOLATED LATE DAY SHOWERS
AND THUNDERSTORMS FROM WHEATLAND TO ALLIANCE.
TUESDAY...SLIGHT DECREASE IN LOW AND MID LEVEL MOISTURE...ACTING AS
THE FUEL FOR THUNDERSTORMS...THUS ONLY ISOLATED STORMS AT
BEST...NORTH OF A RAWLINS TO SCOTTSBLUFF LINE.
WEDNESDAY...DRY WEST WINDS PREVAIL IN THE LOW AND MID
LEVELS...EFFECTIVELY DRYING OUT THE ATMOSPHERE EVEN MORE...AND
PRODUCING A MILD LATE AUGUST DAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 521 AM MDT THU AUG 14 2014
EXPECT INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH
THE MORNING HOURS FOR KRWL AND KLAR WITH SHOWERS SPREADING EAST
THIS AFTERNOON. SOME OF THE STRONGER STORMS WILL PRODUCE HEAVY
RAINFALL THAT COULD REDUCE FLIGHT CONDITIONS TO IFR CONDITIONS
THROUGH THE AFTERNOON HOURS. SHOWERS ENDING LATE THIS EVENING FROM
WEST TO EAST.
&&
.FIRE WEATHER...
ISSUED AT 350 AM MDT THU AUG 14 2014
WIDESPREAD WETTING RAINS TODAY BEGINNING OVER CARBON COUNTY...THEN
SPREADING EAST. THIS IS DUE TO A UPPER LEVEL LOW PRESSURE SYSTEM
MOVING SLOWLY NORTHEAST AND INTERACTING WITH MONSOONAL MOISTURE
OVER THE AREA. THIS LOW WILL KEEP UNSETTLED WEATHER OVER SOUTHEAST
WYOMING AND NEBRASKA PANHANDLE THROUGH FRIDAY AFTERNOON AS THE LOW
SLOWLY MOVES OUT OF THE AREA. DRIER CONDITIONS AFTER FRIDAY
AFTERNOON AS WESTERLY WINDS RETURN. AFTERNOON HUMIDITIES SATURDAY
AND SUNDAY WILL LOOK TO BECOME CRITICAL WEST OF THE LARAMIE RANGE.
GUSTY WESTERLY WINDS AS WELL BOTH AFTERNOONS THAT COULD REACH
CRITICAL CRITERIA.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...CLAYCOMB
LONG TERM...RUBIN
AVIATION...CLAYCOMB
FIRE WEATHER...CLAYCOMB
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
356 AM MDT THU AUG 14 2014
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 350 AM MDT THU AUG 14 2014
LATEST WATER VAPOR IMAGERY SHOWING THE UPPER LEVEL LOW PUSHING
INTO NORTHWESTERN COLORADO THIS MORNING. LOOKS TO BE HANDLED WELL
BY THE ECMWF. LATEST MOSAIC RADAR SHOWING SHOWERS WIDESPREAD OVER
RIVERTONS CWFA WITH SOME SHOWER ACTIVITY OVER CARBON COUNTY.
MESOWEST OBSERVATIONS REPORTING MEASURABLE RAINFALL OVER THE SNOWY
AND SIERRA MADRE RANGES AS WELL AS THE NORTH LARAMIE RANGE.
FOR TODAY...WE SHOULD SEE AN INCREASE IN SHOWERS AND THUNDERSTORMS
AS THE MORNING PROGRESSES. UPPER LOW MOVES OVER CASPER BY 00Z WITH
FAIRLY WIDESPREAD SHOWERS OVER OUR SOUTHERN ZONES. PWATS FOR
RAWLINS FROM THE NAM UP NEAR 1.2 INCHES AT 18Z...NEAR 1.4 INCHES
HERE AT CHEYENNE BY 00Z AND NEAR 1.7 INCHES AT CHADRON BY 06Z THIS
EVENING. LATEST HRRR FORECAST AND FORECAST IR IMAGERY SHOWING
SHOWERS AND THUNDERSTORMS EAST OF THE LARAMIE RANGE BREAKING OUT
HERE AT CHEYENNE AROUND 15Z AND OUT IN THE PANHANDLE AFTER 18Z.
FORECAST STORM MOTIONS A LITTLE HIGHER THAN PREVIOUSLY FORECAST
WITH NAM SHOWING 10-15KTS. GIVEN THAT STORM MOTIONS ARE
HIGHER...HAVE DECIDED TO HOLD OFF ON A FLASH FLOOD WATCH. WOULD
THINK WE COULD SEE SOME FLASH FLOOD WARNING POSSIBLE THIS
AFTERNOON...BUT THESE WILL BE FOR TRAINING STORMS AND NOT FOR SLOW
MOVING STORMS. MAY TAKE ANOTHER LOOK LATER THIS MORNING WHEN THE
06Z MODEL DATA COMES OUT.
LOOKS LIKE SHOWERS AND THUNDERSTORMS WILL COME TO AN END BY 06Z
TONIGHT AS THE ECMWF SHOWS SHORTWAVE MOVING INTO CENTRAL SOUTH
DAKOTA AND CENTRAL NEBRASKA. STILL SOME POSITIVE VORTICITY
ADVECTION OVER THE NORTHERN PANHANDLE FRIDAY MORNING...SO DID KEEP
SOME SLIGHT CHANCE POPS GOING OUT THAT WAY FOR FRIDAY MORNING AND
AFTERNOON.
UPPER RIDGE BUILDS BACK INTO THE AREA FRIDAY NIGHT INTO SATURDAY AS
SHORTWAVE BEGINS TO MOVE SOUTHEAST INTO EASTERN KANSAS. 700MB
WINDS PICKING UP TO 20-25KTS ACROSS THE CWFA MAY LEAD TO
HEIGHTENED FIRE WEATHER CONCERNS SATURDAY...MORE LIKELY THOUGH ON
SUNDAY.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 350 AM MDT THU AUG 14 2014
SATURDAY NIGHT...DRY PERIOD WITH LIMITED LOW AND MID LEVEL MOISTURE
AND DOWNSLOPE WEST WINDS.
SUNDAY...NEXT SHORTWAVE TROUGH ALOFT MOVES ACROSS EASTERN MONTANA
AND EASTERN WYOMING WITH AN ASSOCIATED SURFACE TROUGH. ISOLATED
SHOWERS AND THUNDERSTORMS EXPECTED...NORTH OF A DOUGLAS TO
SCOTTSBLUFF LINE.
MONDAY...RELATIVELY DRY NORTHWEST FLOW ALOFT PREVAILS...THOUGH LOOKS
LIKE ENOUGH LOW AND MID LEVEL MOISTURE FOR ISOLATED LATE DAY SHOWERS
AND THUNDERSTORMS FROM WHEATLAND TO ALLIANCE.
TUESDAY...SLIGHT DECREASE IN LOW AND MID LEVEL MOISTURE...ACTING AS
THE FUEL FOR THUNDERSTORMS...THUS ONLY ISOLATED STORMS AT
BEST...NORTH OF A RAWLINS TO SCOTTSBLUFF LINE.
WEDNESDAY...DRY WEST WINDS PREVAIL IN THE LOW AND MID
LEVELS...EFFECTIVELY DRYING OUT THE ATMOSPHERE EVEN MORE...AND
PRODUCING A MILD LATE AUGUST DAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1129 PM MDT WED AUG 13 2014
TONIGHT...ISOLATED SHOWERS AND THUNDERSTORMS...NORTH OF A LARAMIE
TO ALLIANCE LINE...ENDING BY DAWN. VFR PREVAILS. AREAS OF LATE NIGHT
FOG AND LOW CLOUDS ACROSS WESTERN NEBRASKA PRODUCING MVFR.
THURSDAY...SHOWERS INCREASING IN COVERAGE AND SPREADING FROM
WEST TO EAST...WITH SCATTERED THUNDERSTORMS. WIDESPREAD MOUNTAIN
OBSCURATION. MVFR PREVAILS WITH SHOWERS AND THUNDERSTORMS.
GUSTY AND ERRATIC WINDS NEAR THUNDERSTORMS ALONG WITH LOCALIZED
TURBULENCE. COVERAGE OF STORMS WILL BE GREATER IN THE WEST AND LEAST
IN THE EAST.
&&
.FIRE WEATHER...
ISSUED AT 350 AM MDT THU AUG 14 2014
WIDESPREAD WETTING RAINS TODAY BEGINNING OVER CARBON COUNTY...THEN
SPREADING EAST. THIS IS DUE TO A UPPER LEVEL LOW PRESSURE SYSTEM
MOVING SLOWLY NORTHEAST AND INTERACTING WITH MONSOONAL MOISTURE
OVER THE AREA. THIS LOW WILL KEEP UNSETTLED WEATHER OVER SOUTHEAST
WYOMING AND NEBRASKA PANHANDLE THROUGH FRIDAY AFTERNOON AS THE LOW
SLOWLY MOVES OUT OF THE AREA. DRIER CONDITIONS AFTER FRIDAY
AFTERNOON AS WESTERLY WINDS RETURN. AFTERNOON HUMIDITIES SATURDAY
AND SUNDAY WILL LOOK TO BECOME CRITICAL WEST OF THE LARAMIE RANGE.
GUSTY WESTERLY WINDS AS WELL BOTH AFTERNOONS THAT COULD REACH
CRITICAL CRITERIA.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...CLAYCOMB
LONG TERM...RUBIN
AVIATION...RUBIN
FIRE WEATHER...CLAYCOMB
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1120 PM MDT FRI AUG 15 2014
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 244 PM MDT FRI AUG 15 2014
CONVECTION THIS AFTERNOON HAS BEEN MORE SPARSE TODAY VS
YESTERDAY...AT LEAST AS OF 20Z. HOWEVER...THE MTNS HAVE HAD MORE
SUN TODAY...AND THUNDERSTORMS ARE FIRING OVER THE MOUNTAINS ALONG
THE LEADING EDGE OF A WEAK SHORTWAVE MOVING INTO WESTERN CO.
VARIOUS HIGH RES MODELS INCREASE THUNDERSTORM COVERAGE ACROSS THE
MOUNTAINS...THEN SPREAD THEM EASTWARD INTO THE ADJACENT PLAINS
DURING THE AFTERNOON AND EVENING HOURS. SFC DEW POINTS HAVE BEEN
LOWER TODAY...DROPPING OFF INTO THE LOWER 40S AND EVEN SOME UPPER
30S ACROSS THE MOUNTAINS...WITH UPPER 40S TO MID 50S ACROSS THE
PLAINS...AND THIS HAS LIMITED CAPE TO AROUND 500 J/KG ACCORDING TO
SPC MESO ANALYSIS. PRECIP WATERS ARE RUNNING LOWER AS
WELL...AROUND 80% OF NORMAL IN THE NORTH TO 130% OF NORMAL IN THE
SOUTH BASED ON THE BLENDED TPW SATELLITE PRODUCT.
THUS...THUNDERSTORMS SHOULD NOT BE AS EFFICIENT HEAVY RAINFALL
PRODUCERS AS THEY WERE YESTERDAY. THAT SAID...THERE IS STILL
SUFFICIENT MOISTURE FOR LOCALLY HEAVY RAIN WITH THE STRONGER
STORMS. IF ONE OF THESE HITS BURN SCARS OR AREAS OF STEEP
TERRAIN...THEN LOCALIZED FLASH FLOODING WILL STILL BE A CONCERN.
FORTUNATELY...STORMS APPEAR TO BE MOVING PRETTY GOOD (SOUTHEAST AT
15 MPH)...WHICH MAY LIMIT THREAT SOME. HRRR SUGGESTS GREATEST
THREAT WINDOW FOR THE WALD0 WILL BE FROM 21Z-00Z. THE PAPOOSE AND
WEST FORK BURN SCARS AS WELL AS THE CONTINENTAL DIVIDE WILL SEE
THE GREATEST THREAT BETWEEN 20Z AND 00Z. THUNDERSTORMS MAY MOVE
OFF INTO THE ADJACENT PLAINS THROUGH THE LATE AFTERNOON AND
EVENING...BUT THEY DON`T LOOK TOO ORGANIZED AND THERE ISN`T MUCH
OF A LOW LEVEL JET TO HELP SUSTAIN CONVECTION AFTER DARK...SO WILL
END MOST POPS BY MIDNIGHT.
SATURDAY LOOKS EVEN DRIER THAN TODAY AS PRECIPITABLE WATERS FALL OFF
TO LESS THAN AN .75 INCHES ALONG/WEST OF I-25. STILL ENOUGH
MOISTURE FOR ISOLATED DIURNAL THUNDERSTORMS...BUT COVERAGE SHOULD BE
EVEN LOWER. STILL ENOUGH MOISTURE FOR LOCALLY HEAVY RAIN WITH THE
STRONGER CELLS...BUT THREAT SHOULD BE LOWER DUE TO THE LIMITED
COVERAGE. TEMPERATURES TOMORROW SHOULD BE A FEW DEGREES WARMER THAN
TODAY. -KT
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 244 PM MDT FRI AUG 15 2014
EXTENDED FORECAST FOR SE CO LOOKS PRETTY TYPICAL FOR THE MIDDLE
OF AUGUST. DAILY STORM CHANCES AND TEMPS AROUND 90 DEGREES FOR THE
PLAINS. MAIN QUESTION WILL BE THE PROGRESSION OF A W COAST CUTOFF
LOW AND PACNW TROUGH...ESPECIALLY LATE IN THE PERIOD.
SAT NIGHT...CONVECTION SHOULD BE WRAPPING UP PRETTY EARLY AFTER
SUNSET. WILL LEAVE HIGHEST POPS SAT EVE OVER THE RATON MESA AND
FAR SERN PLAINS...WHERE THE MODELS ARE FOCUSING THE HEAVIEST QPF.
SUNDAY...A SHORT WAVE DISTURBANCE WILL PUSH THROUGH IN THE NW FLOW
LATE IN THE DAY. LOOKS LIKE THE MAIN IMPACT FROM THIS DISTURBANCE
WILL COME AFTER 00Z...AND BE FOCUSED ON THE PIKES PEAK REGION AND
PALMER DVD. EXPECT STORMS TO DEVELOP OVER THE MTS SOMEWHAT LATER
THAN USUAL...MOSTLY AFTER 20Z...AND IT WILL BE ISOLD-SCT IN COVERAGE.
THE SHORTWAVE SHOULD RESULT IN MORE WIDESPREAD COVERAGE OF STORMS
BUT THERE IS STILL SOME UNCERTAINTY ON HOW FAR WEST THE BULK OF THE
DEVELOPING CLUSTER OF STORMS WILL BE. HAVE THE HIGHEST POPS FROM THE
PIKES PEAK AREA SEW TO KLAA...FROM 00-03Z. SUNDAY SHOULD BE THE
WARMEST DAY OF THE PERIOD AS H7 TEMPS CLIMB TO NR 17 DEG C IN THE
AFTERNOON. COULD SEE A FEW SPOTS CLIMB INTO THE UPPER 90S OVER THE
LOWER ARKANSAS VALLEY.
MONDAY...THE MAIN FOCUS FOR ANY CONVECTION WILL BE OVER THE ERN
MTS AS LIGHT UPSLOPE FLOW PERSISTS ON THE BACKSIDE OF THE TROUGH
MOVING THROUGH THE UPPER MISS VALLEY. WILL KEEP ISOLD-SCT POPS THERE
WITH MORE ISOLD ACTIVITY POSSIBLE OVER THE BALANCE OF THE ERN PLAINS
AND SAN LUIS VALLEY. IF TRENDS CONTINUE...MAY BE ABLE TO DROP
MENTIONABLE POPS FROM ALL BUT THE MTS ON MONDAY.
TUESDAY...WILL SEE THE START OF A SWITCH BACK TO INCREASING MONSOONAL
MOISTURE. THE CUTOFF OFF THE CA COAST MAY BEGIN TO RETROGRADE DURING
THIS PERIOD...WHILE A TROUGH IN THE PACNW BEGINS MOVING INTO ID AND
MT. THE ECMWF CONTINUES OT BE A LITTLE MORE AGGRESSIVE IN BRINGING A
RETURN OF MONSOONAL MOISTURE TO THE AREA...WHILE THE GFS HOLDS BACK
A BIT. LOW POPS LOOK APPROPRIATE FOR THE REGION...ISOLD FOR THE
LOWER ELEVS AND SCT IN THE MTS.
BY WED-FRI...THE PACNW TROUGH SHOULD START TO ADVANCE INTO THE NRN
ROCKIES...AS THE UPPER HIGH TO OUR SW SHIFTS INTO ERN TX. THIS SHOULD
BRING A RETURN TO A STRONGER MONSOONAL PATTERN...WITH MORE MOISTURE
BEING DRAWN NWD FROM THE SUBTROPICS INTO WRN CO. WILL LEAVE LOW
ENSEMBLE POPS INTACT FOR NOW...BUT IF TRENDS CONTINUE MAY HAVE TO
SLOWLY RAMP UP POPS FOR THE END OF THE WEEK. ROSE
&&
.AVIATION...ISSUED AT 1120 PM MDT FRI AUG 15 2014
VFR CONDITIONS ARE EXPECTED OVER THE KALS...KCOS AND KPUB TAF
SITES FROM TONIGHT INTO SATURDAY.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MIAMI FL
157 AM EDT SAT AUG 16 2014
.AVIATION...
THE WEATHER WILL BE MAINLY QUIET THROUGH ABOUT MID-MORNING, WHEN
CONVECTION IS EXPECTED TO DEVELOP ONCE AGAIN. AN ATLANTIC SEA
BREEZE SHOULD BEGIN TO PUSH INLAND AROUND 16Z, AND BECOME A
TRIGGER FOR SHOWERS AND STORMS. THERE IS SOME UNCERTAINTY AS TO
HOW FAR INLAND THE STORMS WILL OCCUR TODAY, SO KEPT THE VCTS IN
THE TAFS FOR NOW, RATHER THAN ADDING A PROB30 GROUP. CONVECTION
LOOKS TO CONTINUE THROUGH AROUND 23Z OR SO. OTHERWISE, VFR
CONDITIONS, EXCEPT BRIEF IFR POSSIBLE UNDER HEAVY SHOWERS.
&&
.PREV DISCUSSION... /ISSUED 807 PM EDT FRI AUG 15 2014/
AVIATION...54/BNB
PREV DISCUSSION... /ISSUED 750 PM EDT FRI AUG 15 2014/
UPDATE...STRONG THUNDERSTORMS WITH TORRENTIAL RAINS AFFECTED THE
EAST COAST EARLIER, BUT HAS SINCE ENDED. ADDITIONAL ACTIVITY IS
NOW MOVING IN FROM THE WEST...WITH THE STRONGEST STORMS OVER THE
GULF WATERS. ADJUSTED POPS/WEATHER BASED ON THESE TRENDS. ACTIVITY
WILL SLOWLY WANE WITH THE LOSS OF HEATING. /GREGORIA
PREV DISCUSSION... /ISSUED 313 PM EDT FRI AUG 15 2014/
DISCUSSION...
AS OF 1830Z...VERY ACTIVE CONVECTION ACROSS THE ATLANTIC COAST
AND THE ADJACENT ATLANTIC WATERS. VERY ACTIVE THUNDERSTORMS EXTEND
FROM NORTHEAST MIAMI DADE NORTHWARD THROUGH EASTERN BROWARD AND
PALM BEACH COUNTIES. THE LATEST HRRR MESO-SCALE MODEL GUIDANCE
WHICH INITIALIZED GENERALLY WELL ON THIS CONVECTION INDICATES
THIS ACTIVITY STARTING TO DISSIPATE AROUND 22Z. BUT AS ALWAYS WITH
EXISTING OUTFLOW BOUNDARIES ADDITIONAL CONVECTION COULD LINGER
INTO THE EARLY EVENING HOURS WITH THE CURRENT FORECAST INDICATING
ACTIVE CONVECTION WITH NUMEROUS SHOWERS/THUNDERSTORMS ACROSS THE
EASTERN HALF OF THE PENINSULA THROUGH 00Z THIS EVENING.
THE LATEST MODEL GUIDANCE INDICATES SOME RELATIVELY DRIER AIR
FORECAST TO MOVE NORTHWARD INTO THE FLORIDA STRAITS TONIGHT INTO
SATURDAY. HOWEVER...THE GUIDANCE INDICATES THAT IT MAY NOT MAKE IT
FAR ENOUGH NORTHWARD ON SATURDAY SUCH THAT LINGERING DEEP
MOISTURE OVER MOST OF THE PENINSULA AND ADJACENT WATERS COULD LEAD
TO ADDITIONAL AFTERNOON SHOWERS/THUNDERSTORMS ACROSS THE REGION
WITH THE SATURDAY FORECAST INDICATING THE GREATEST COVERAGE ACROSS
THE INTERIOR ALTHOUGH SCATTERED ACTIVITY IS FORECAST FOR THE GULF
AND ATLANTIC COAST METRO AREAS. BY SUNDAY THE GUIDANCE INDICATES
THAT THE DRIER AIR IS FORECAST TO CONTINUE MOVING NORTH WITH A
CONSIDERABLE REDUCTION ACROSS THE REGION IN SHOWERS/THUNDERSTORMS
WITH MAINLY THE INTERIOR REGIONS FORECAST TO HAVE SCATTERED
ACTIVITY.
THERE IS GUIDANCE SUGGESTING THAT SOME DUST ASSOCIATED WITH THE SAHARAN
AIR LAYER COULD ENTER THE REGION LATE SATURDAY INTO SUNDAY THEN
MOVE ACROSS THE REGION LATE SUNDAY AND PERSIST INTO EARLY NEXT
WEEK. SO THERE MAY BE NOTICEABLY HAZY SKIES SUNDAY INTO EARLY
NEXT WEEK.
MARINE...
LIGHT SOUTH TO SOUTHWEST WINDS ARE FORECAST ACROSS THE REGIONAL
WATERS TONIGHT THROUGH SATURDAY. BY SUNDAY WINDS ARE FORECAST TO
BECOME EAST TO SOUTHEAST WHILE REMAINING AROUND OR BELOW 10 KNOTS
AND PERSISTING INTO EARLY NEXT WEEK. REGIONAL SEAS ARE FORECAST TO
BE 2 FEET OR LESS THROUGH THE WEEKEND INTO AT LEAST EARLY NEXT
WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 90 78 91 79 / 50 20 20 10
FORT LAUDERDALE 91 80 91 81 / 50 20 20 10
MIAMI 91 79 91 80 / 40 10 20 10
NAPLES 90 78 91 78 / 30 10 20 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...10/CD
LONG TERM....13/SI
AVIATION...13/SI
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1259 AM CDT SAT AUG 16 2014
.DISCUSSION...
254 PM CDT
THE MAIN FORECAST CONCERNS WILL CONTINUE TO FOCUS ON THE CHANCES OF
THUNDERSTORMS AND THE POSSIBILITY OF HEAVY RAIN ACROSS PORTIONS OF MY
AREA THROUGH THE WEEKEND.
COOL SURFACE HIGH PRESSURE CONTINUES TO SHIFT EAST-SOUTHEASTWARD
OVER THE OHIO VALLEY EARLY THIS AFTERNOON. THIS IS PRODUCING ANOTHER
FABULOUS WEATHER DAY ACROSS THE REGION THIS AFTERNOON WITH
TEMPERATURES PRIMARILY IN THE MID TO UPPER 70S. HOWEVER...ATTENTION
IS BEGINNING TO FOCUS ON THE SYSTEM TO OUR WEST...WHICH IS ALREADY
PUSHING SOME HIGHER LEVEL CLOUDINESS INTO MY SOUTHWESTERN AREAS.
WATER VAPOR IMAGERY EARLY THIS AFTERNOON INDICATES THE PRESENCE OF A
COUPLE OF MID/UPPER LEVEL DISTURBANCES ACROSS THE PLAINS. THE FIRST
IS LOCATED OVER THE WESTERN DAKOTAS...WITH THE SECOND OVER THE
NEBRASKA-KANSAS BOARDER. HOWEVER...IT IS THE SOUTHERNMOST
DISTURBANCE THAT IS THE MAIN FOCUS FOR THE WEATHER EXPECTED MUCH OF
THIS WEEKEND ACROSS NORTHERN ILLINOIS/NORTHWESTERN INDIANA. MODEL
GUIDANCE IS IN GOOD AGREEMENT WITH TRACKING THIS DISTURBANCE SLOWLY
EASTWARD ACROSS SOUTHERN IOWA TONIGHT...THEN EAST-SOUTHEASTWARD
ACROSS CENTRAL ILLINOIS BY SUNDAY MORNING. THE GFS AND ECMWF ARE
FAVORED WITH THE HANDLING OF THE SYSTEM THROUGH THE WEEKEND.
CONVECTIVE ACTIVITY WILL LIKELY FIRE UP DOWNSTREAM OF THE SOUTHERN
NEBRASKA DISTURBANCE TONIGHT...NAMELY ACROSS PORTIONS OF SOUTHERN
IOWA...MISSOURI AND PERHAPS ACROSS FAR WESTERN ILLINOIS ALONG THE
NOSE OF A DEVELOPING SOUTH-SOUTHWESTERLY LOW LEVEL JET. THE REMNANTS
OF SOME OF THIS ACTIVITY WILL TRY TO MOVE EASTWARD ACROSS THE AREA
SATURDAY MORNING. HOWEVER...IT APPEARS THIS ACTIVITY WILL LIKELY
WEAKEN CONSIDERABLY WITH EASTWARD EXTENT DURING THE MORNING AS IT
MOVES AWAY FROM THE BETTER FORCING AND INSTABILITY. AS SUCH...IT
APPEARS THE THREAT FOR THUNDERSTORMS WILL BE LOW ACROSS MUCH OF
NORTHEASTERN ILLINOIS AND INTO INDIANA...WITH POSSIBLY ONLY SOME
SHOWERS VOID OF THUNDER POSSIBLE.
ADDITIONAL SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE SATURDAY
AFTERNOON AND NIGHT AS THE MAIN UPPER SYSTEM MOVES FROM SOUTHEASTERN
IOWA OVER CENTRAL ILLINOIS. HOWEVER...AGAIN IT APPEARS THE MAIN
THREAT OF THUNDER WILL REMAIN ALONG AND SOUTH OF INTERSTATE 80 TO
THE EAST OF THE TRACK OF THE MID LEVEL WAVE. THERE IS A THREAT FOR
SOME VERY HEAVY RAINFALL WITH THESE STORMS ON SATURDAY/SATURDAY
NIGHT ACROSS CENTRAL ILLINOIS GIVEN PWATS COULD BE IN EXCESS OF 2
INCHES AND WARM CLOUD DEPTHS IN EXCESS OF 13,000 FEET. THIS THREAT
WILL NEED TO BE WATCHED...BUT AT THIS TIME IT APPEARS THE PRIMARILY
THREAT FOR THIS HEAVY RAINFALL COULD REMAIN JUST OUTSIDE MY AREA.
A COLD FRONT IS ALSO EXPECTED TO DROP DOWN LAKE MICHIGAN LATE
SATURDAY. THIS COLD FRONT SHOULD SHIFT SOUTHWARD ACROSS NORTHERN
ILLINOIS BY LATE SATURDAY NIGHT/EARLY SUNDAY MORNING. ONCE THIS
FRONT PUSHES THROUGH...ONSHORE FLOW WILL PREVAIL ACROSS NORTHEASTERN
ILLINOIS AND PORTIONS OF NORTHWESTERN INDIANA. THIS SHOULD KEEP MUCH
OF NORTHERN ILLINOIS DRY BUT CLOUDY ON SUNDAY. AS A RESULT...I
HAVE DROPPED POPS ACROSS MUCH OF NORTHERN ILLINOIS ON SUNDAY.
HOWEVER...THE EFFECTS OF THE MID LEVEL SYSTEM WILL STILL POSSIBLY
LEAD TO ADDITIONAL THUNDERSTORMS SUNDAY...PRIMARILY ACROSS MY EAST
CENTRAL ILLINOIS AND NORTHWESTERN INDIANA COUNTIES. HEAVY RAINFALL
WILL AGAIN BE A THREAT WITH THESE STORMS.
THINGS FINALLY QUITE DOWN AREA-WIDE FOR A SHORT PERIOD LATE MONDAY.
HOWEVER...THE WEATHER PATTERN FROM MID TO LATE THIS COMING WEEK
LOOKS TO BE A WARMER AND ACTIVE AT TIMES. THE UPPER LOW/TROUGH
CURRENT IN PLACE ACROSS THE PACIFIC NORTHWEST IS PROGGED TO SHIFT
EASTWARD ACROSS THE UPPER MIDWEST BY TUESDAY. THIS WILL BRING OUR
NEXT CHANCE OF SHOWERS AND STORMS TO AREA...ALONG WITH WARMER
TEMPERATURES. ADDITIONAL WAVES OF STORMS ARE POSSIBLE LATER IN THE
WEEK AS WELL WITH THE LIKELIHOOD OF THE MID/UPPER LEVEL PATTERN
REMAINING DISTURBED ACROSS THE NORTHERN HALF OF THE COUNTRY.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* SOUTHWEST WINDS UP TO 10 KT AT TIMES SATURDAY AFTERNOON.
* A CHANCE FOR SHOWERS AND A SMALLER CHANCE OF THUNDERSTORMS FROM
MID SATURDAY AFTERNOON THROUGH EARLY SATURDAY EVENING.
KREIN
//DISCUSSION...UPDATED 06Z...
HIGH PRESSURE CONTINUES TO SETTLE SOUTHEAST INTO THE CNTRL
APPALACHIANS AS LOW PRESSURE TRACKS THROUGH SRN ONTARIO AND
ANOTHER LOW MOVES INTO SWRN IOWA. WINDS HAVE DROPPED OFF TO LIGHT
AND VARIABLE OR LIGHT SWLY AS A RIDGE AXIS EXTENDS NORTHWEST FROM
THE SFC HIGH INTO SRN MN. THROUGH THE NIGHT AND TOMORROW
MORNING...A COLD FRONT ASSOCIATED WITH THE CANADIAN LOW WILL
BEGIN TO PUSH SOUTH DOWN THE LENGTH OF LAKE MICHIGAN WHILE THE
OTHER SFC LOW MOVES ALONG THE IA/MO BORDER. SHOWERS AND
THUNDERSTORMS AT THE NOSE OF A LOW LEVEL JET...AT 06Z...EXTEND
FROM NWRN MO/SWRN IA THROUGH ERN MO. THE LATEST HIGH RES MODEL
GUIDANCE INDICATES THAT THIS LOW WILL MOVE VERY SLOWLY ONLY TO THE
SERN CORNER OF IA OR THE NERN CORNER OF MO. WARM MOIST ADVECTION
IN THE SWLY SLOW AHEAD OF THE LOW WILL CONTINUE TO DRAW MOISTURE
NEWD THROUGH IL..SETTING UP WIDESPREAD SHOWERS AND EMBEDDED
THUNDERSTORMS INTO CENTRAL IL THROUGH THE MORNING HOURS
SATURDAY...WITH SOME SHOWERS POSSIBLE REACHING THE I-80 CORRIDOR
BY ARND 18Z. THE TREND OF THE UPPER LEVEL SYSTEM ASSOCIATED WITH
THIS SFC LOW IS TRENDING A LITTLE FARTHER SOUTH THAN PREVIOUS
GUIDANCE...SO THERE IS A DECREASING LIKELIHOOD OF WIDESPREAD PCPN
REACHING THE TERMINALS. WILL MAINTAIN THE VCSH GROUP FOR THE LATE
AFTERNOON AS THE HIGH RES GUIDANCE DOES INDICATE SOME PCPN
SNEAKING INTO NERN IL...INVOF THE CHICAGO AREA TERMINALS...BUT
WITH THE AREA SITTING BETWEEN THE SFC LOW AND A COLD FRONT PUSHING
SOUTH THROUGH WI AND LAKE MICHIGAN...THERE COULD BE ENOUGH SFC
DIVERGENCE THAT PCPN COULD BE MINIMIZED.
SFC WINDS SHOULD REMAIN GENERALLY SWLY OVERNIGHT AND THROUGH THE
DAY TOMORROW. THERE REMAINS SOME QUESTION ABOUT WIND SPEEDS.
PREVAILING SFC WINDS SHOULD REMAIN GENERALLY UNDER 10KT THROUGH
THE DAY AS A WEAK SFC PRESSURE GRADIENT WILL BE IN PLACE...BUT
WINDS ALOFT WILL BE IN THE INCREASE THROUGH THE DAY AS THE MID
LEVEL SYSTEM APPROACHES THE MIDDLE MISSISSIPPI VALLEY. MODEL
SOUNDINGS INDICATE THAT SWLY-WLY WINDS OF 15-20KT WILL MOVE OVER
THE AREA BY LATE MORNING AND THROUGH THE AFTERNOON. HOWEVER...WITH
THE ANTICIPATION OF INCREASING CLOUD COVER...LOW LEVEL MIXING MAY
NOT BE SUFFICIENT TO TAP THE STRONGER WINDS. SO...WHILE THERE
COULD BE OCNL GUSTS OF 12-14KT...DO NOT ANTICIPATE THAT GUSTS OF
THIS MAGNITUDE WILL BE FREQUENT.
THE NEXT CONCERN WILL BE ASSOCIATED WITH THE COLD FRONT PUSHING
SWD THROUGH WI AND DOWN LAKE MICHIGAN. THE LATEST GUIDANCE
SUGGESTS THAT THE FRONT WILL NOT REACH THE CHICAGO AREA TERMINALS
UNTIL AROUND MIDNIGHT AND A LITTLE LATER FOR RFD DUE TO THE FASTER
SURGE OF THE FRONT OVER THE LAKE. WINDS SHOULD TURN NELY FOLLOWING
THE FROPA AND INCREASE TO 10-15KT. NELY FLOW WILL ALSO DRAW LAKE
COOLED AIR INTO NERN IL/NWRN IN...AND CIGS SHOULD LOWER INTO LOWER
END MVFR LEVELS LATE TOMORROW NIGHT. THERE IS ALSO A CHANCE FOR
VIS RESTRICTIONS OF 3-5SM BR AS WELL.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS THROUGH TOMORROW EVENING.
* MEDIUM CONFIDENCE IN THE TIMING OF THE FROPA TOMORROW NIGHT AND
THE WIND SHIFT TO NELY.
* LOW IN WHETHER ANY SHOWERS WILL DEVELOP AS FAR NORTH AS THE
CHICAGO AREA TERMINALS ON SATURDAY AFTERNOON AND EVENING.
KREIN
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...NORTHEAST WINDS OVER 10 KT WITH PROBABLE MVFR CIGS IN THE
MORNING.
MONDAY...NORTHEAST WINDS.
TUESDAY-THURSDAY...CHANCE OF TSRA.
MTF
&&
.MARINE...
215 PM CDT
LARGE AREA OF HIGH PRESSURE CENTERED JUST SOUTH OF LAKE MICHIGAN
WILL SHIFT SOUTHEAST TONIGHT. A WEAK LOW PRESSURE SYSTEM IN SOUTH
CENTRAL CANADA WILL DEEPEN SOME TONIGHT AS IT PASSES JUST NORTH OF
THE UPPER GREAT LAKES REGION. THE PRESSURE GRADIENT INCREASES
OVERNIGHT INTO EARLY SATURDAY MORNING...ESPECIALLY ALONG THE
NORTHERN HALF OF THE LAKE. THIS WILL MAINTAIN SW FLOW
TONIGHT...WITH WINDS APPROACHING 25-30 KT FOR A BRIEF TIME IN THE
NORTH LATE TONIGHT. BEHIND THE LOW...HIGH PRESSURE BUILDS INTO
SOUTHERN ONTARIO AND SENDS A COLD FRONT SOUTH DOWN THE LAKE
SATURDAY AFTERNOON AND EVENING. ADDITIONALLY...AN AREA OF LOW
PRESSURE IN THE CENTRAL PLAINS WILL SLOWLY DRIFT EAST TO THE OHIO
VALLEY BY LATE SUNDAY THEN CONTINUE TO THE ATLANTIC SEABOARD
MONDAY. THIS WILL HELP MAINTAIN OR A PERIOD OF NORTH TO
NORTHEASTERLY WINDS. ADDITIONAL WEAKER LOW PRESSURE AREAS WILL
PUSH TOWARD THE GREAT LAKES NEXT WEEK...MAINTAINING A SOUTH
COMPONENT TO THE WIND WITH OCCASIONAL THUNDERSTORMS THROUGH MID
WEEK.
KMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1154 PM CDT Fri Aug 15 2014
.UPDATE...
ISSUED AT 904 PM CDT FRI AUG 15 2014
A few weakening disturbances are set to move through central
Illinois through Saturday. The first is largely through Illinois
already, moving rapidly off to the east, and resulted in isolated
to scattered showers from around Galesburg to Lawrenceville
earlier in the evening. The next is moving ESE through Missouri at
this time producing widespread showers and a few thunderstorms.
HRRR model progs bring this into central IL over the next few
hours, again mainly affecting Galesburg to Lawrenceville southward
while weakening as instability fades with the loss of daytime
heating. By Saturday afternoon, yet another disturbance is
expected to approach as a deeper slow moving 500 mb trough and
surface low develop over northeast Missouri. Precipitable water
values over 2 inches inches are expected to be associated with the
system, so there will be a threat for heavy rain as this moves
across southern Illinois Saturday evening. Have updated forecast
to account for temperature, humidity and precipitation trends
over the next several hours.
&&
.SHORT TERM...(This evening through Saturday)
ISSUED AT 307 PM CDT FRI AUG 15 2014
Decaying MCS moving toward the CWA early this afternoon, with some
light showers being reported near Galesburg. Most precipitation
still west of the Mississippi River, with the HRRR showing it
reaching about as far east as Springfield late this afternoon before
diminishing. Latest LAPS soundings from Springfield and Jacksonville
showing a fair amount of dry air below 700 mb, so am not expecting a
lot of accumulation out of this.
Shortwave currently moving southeast out of South Dakota/Nebraska
starting to produce additional storms in Kansas, and this area of
storms should expand as the wave moves eastward and the low level
jet increases. HRRR and NAM show this next MCS approaching far
western Illinois by late evening, but the other high-res models such
as the ARW and NMM are a bit slower with arrival across the western
CWA after about 2-3 am. All models show the MCS diminishing during
the morning, but redevelopment taking place toward late afternoon in
the west near a surface low in southeast Iowa. Extensive cloud cover
should mitigate much of the severe weather potential, but
precipitable water values increasing to over 2 inches will result in
some locally heavy rains.
&&
.LONG TERM...(Saturday night through Friday)
ISSUED AT 307 PM CDT FRI AUG 15 2014
Occluded low pressure will reach western IL around 00z/7pm Saturday,
bringing abundant moisture with the potential for some heavy rains.
The latest model runs have shown a diminishing threat for strong
storms in western IL, and SPC has reduced the 5% threat area to just
west of a line from Rushville to Springfield. The threat for thunder
in general will remain low due to limited ice formation and only
weak instability. Limited afternoon sunshine after morning rain
showers will also help to keep instability in check for Saturday
evening. Rain will be likely during the evening southwest of
Lincoln, then expand to the Indiana border after midnight Sat night.
Likely rain will continue on Sunday east of I-55 as the slow moving
low pressure system moves to near LWV by 00z/7pm Sunday. Bufkit
sounding analysis shows better instability ahead of the low in our
southeast areas Sunday afternoon, with MUCAPE up to 1500 J/kg, but
confidence is low that storms will become very strong due to limited
sunshine once again.
Precipitable water values will remain very high through Sunday with
2" to 2.3" across most of central and southeast IL. Locally heavy
rainfall from Saturday through Sunday evening could push 2 day totals
between 2" and 3".
As the low pulls east of IL on Sunday night, we expect diminishing
precip chances from west to east, with a break in the rain expected
at least on Monday. The Canadian GEM still indicated lingering
rain in most of our area, so we left some slight chance PoPs for
Monday.
The next weather system will arrive quickly late Monday night and
Tuesday, with increasing precip chances NW of the IL Monday night.
Relatively good agreement of a warm front moving east across IL on
Tuesday prompted chance PoPs across the board. The upper trough will
deepen into IL on Tuesday night and Wed, with a trailing cold front
lingering across IL through Thursday, keeping rain chances
entrenched in the forecast through Thursday night. Warm and very
muggy air will dominate the mid week period with the rain chances,
as dewpoints remain in the low 70s and highs climb into the mid to
upper 80s.
Friday should bring a break in the rain as upper level ridging
develops bringing even warmer air into central IL the following
weekend.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
ISSUED AT 1154 PM CDT FRI AUG 15 2014
Light showers and local MVFR ceilings from around K1H2 to KGBG
southward this evening as low pressure deepens to the west over
southern IA/northern MO. As the low moves slowly toward central
IL, isold TSRA will be able to develop, however any MVFR
cigs/VSBYS look to be too localized for mention in area TAFs. A
series of disturbances associated with the low pressure system
will bring periods of redevelopment of showers through the
remainder of the 24-hour TAF period, with ceilings just above MVFR
thresholds. There may be a break in shower activity from around
16Z-22Z, but timing is too uncertain for explicit mention of a
break in showers, and daytime heating will bring an increasing
threat for thunderstorms. Time-height plots show very little
improvement in ceilings after lowering to around 4-5 kft AGL
overnight.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...ONTON
SHORT TERM...GEELHART
LONG TERM...SHIMON
AVIATION...ONTON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
333 AM EDT SAT AUG 16 2014
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 351 PM EDT FRI AUG 15 2014
WV IMAGERY AND RUC ANALYSIS INDICATED NW MID/UPPER LEVEL FLOW
THROUGH THE WRN GREAT LAKES BETWEEN A RIDGE FROM THE NRN PLAINS INTO
CNTRL ALBERTA AND A TROUGH OVER QUEBEC. AN UPSTREAM SHORTWAVE TROUGH
AND ASSOCIATED COLD FRONT WAS DIVING SE THROUGH NW ONTARIO. AT THE
SFC...LIGHT SW WINDS PREVAILED ACROSS UPPER MI AS HIGH PRES SINKS
INTO THE SRN LAKES.
TONIGHT INTO SAT...EXPECT SHRA/TSRA TO DEVELOP MAINLY AFT 06Z OVER
NORTHERN LAKE SUPERIOR THAT WILL SPREAD QUICKLY SE AS MODELS WERE IN
GOOD AGREEMENT IN BRINGING THE SHORTWAVE TROUGH WITH MODERATE 700-300
MB QVECTOR CONV...STRONG UPPER LEVEL DIV WITH THE LEFT EXIT OF A 90
KNOT 250-300 MB JET...AND AN ASSOCIATED COLD FRONT THROUGH THE NRN
GREAT LAKES. MODELS SHRTWV FORCING SUGGEST THAT THE ERN CWA WILL SEE
THE GREATEST PCPN COVERAGE/QPF WITH LIKELY TO CATEGORICAL POPS. GIVEN
POTENTIAL OF MUCAPE TO NEAR 800 J/KG... MODERATE TO STRONG DYNAMICS
AND EFFECTIVE SHEAR TO 40 KNOTS SOME EVEN MAINLY ELEVATED STORMS
ABOVE THE SHALLOW BNDRY LAYER MAY BE STRONG CAPABLE OF PRODUCING SOME
GUSTY WINDS AND SMALL HAIL. BY SAT AFTERNOON IN THE WAKE OF THE
FRONT...PCPN CHANCES SHOULD DIMINISH ACROSS THE NORTH WITH COOLER
MORE STABLE AIR MOVING IN ON LOW LEVEL NRLY FLOW. SOME DRIZZLE MAY
LINGER IN THE HIGHER TERRAIN N CNTRL IN THE MORNING IN THE WAKE OF
ANY SHOWERS EARLIER IN THE MORNING.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 333 AM EDT SAT AUG 16 2014
NAM SHOWS SOME SHORTWAVE RIDGING OVER THE UPPER GREAT LAKES 12Z SUN
WITH TROUGHING MOVING INTO THE NORTHERN PLAINS ON SUN. THIS TROUGH
AFFECTS THE AREA MON INTO MON NIGHT. NAM SHOWS SOME DEEPER MOISTURE
AND 850-500 MB Q-VECTOR CONVERGENCE ARRIVING LATE MON AFTERNOON INTO
THE WESTERN CWA AND THIS OVERSPREADS THE CWA MON NIGHT. WILL HAVE
QUIET WEATHER THROUGH MON BEFORE POPS ARRIVE MON NIGHT ACROSS THE
WESTERN HALF OF THE CWA. DID NOT MAKE TOO MANY CHANGES TO THE GOING
FORECAST FOR TEMPERATURES AND CONTINUED THE DRY WEATHER SUN THROUGH
MON.
IN THE EXTENDED...GFS AND THE ECMWF SHOW A 500 MB TROUGH IN THE
UPPER GREAT LAKES REGION 12Z TUE WHICH REMAINS STATIONARY INTO
WED...THEN THIS TROUGH HEADS NORTHWARD 12Z THU AS IT ENCOUNTERS A
RIDGE ACROSS EASTERN CANADA. WHAT THIS WILL MEAN IS THE WEATHER WILL
REMAIN UNSETTLED WITH SFC FRONTS NEAR THE AREA AND TEMPERATURES WILL
BE ABOVE NORMAL. WILL HAVE SOME POPS FOR THE WHOLE PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 131 AM EDT SAT AUG 16 2014
DISTURBANCE AND ASSOCIATED COLD FRONT WILL SWEEP S ACROSS THE AREA
OVERNIGHT/EARLY THIS MORNING. INITIALLY...CONDITIONS WILL BE VFR AT
KWID/KCMX/KSAW. SHRA/ISOLD TSRA ALONG COLD FRONT WILL BE MORE LIKELY
TO AFFECT KCMX/KSAW THAN KIWD. WITH THUNDER LIKELY TO CONTINUE
DIMINISHING ALONG COLD FRONT...RETAINED ONLY A MENTION OF -SHRA
IN FCST. BEHIND FRONT...A PERIOD OF IFR CIGS IS LIKELY AT ALL
TERMINALS THIS MORNING UNDER MOIST UPSLOPE FLOW...ESPECIALLY AT KSAW
DUE TO UPSLOPE FLOW OFF THE COLDER ERN PORTION OF LAKE SUPERIOR.
IMPROVEMENT TO VFR SHOULD OCCUR AT KIWD/KCMX EARLY AFTN WHILE KSAW
MAY ONLY IMPROVE TO MVFR. VFR CONDITIONS SHOULD RETURN TO KSAW EARLY
THIS EVENING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 348 PM EDT FRI AUG 15 2014
EXPECT WINDS UNDER 20 KTS THRU NEXT WED AS A RELATIVELY WEAK PRES
GRADIENT DOMINATES THE UPPER GREAT LAKES ABOVE THE CHILLY WATERS OF
LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...07
AVIATION...ROLFSON
MARINE...KC
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
330 AM EDT SAT AUG 16 2014
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO/MARINE
.SYNOPSIS...
ISSUED AT 323 AM EDT SAT AUG 16 2014
SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE TODAY WITH THE
GREATEST LIKELIHOOD ACROSS CENTRAL LOWER MI THIS AFTERNOON WITH LESS
COVERAGE ANTICIPATED ACROSS SOUTHERN LOWER MI THIS EVENING AND
TONIGHT. MOST OF SUNDAY AND MONDAY WILL BE DRY ALTHOUGH A FEW
SHOWERS MAY POP UP BOTH DAYS MAINLY SOUTH OF A GRAND RAPIDS TO
LANSING LINE. TUESDAY THROUGH FRIDAY LOOKS WARM AND UNSETTLED AT
TIMES WITH OPPORTUNITIES FOR MORE SHOWERS AND STORMS.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 323 AM EDT SAT AUG 16 2014
NOT MUCH HAS CHANGED WITH PREVIOUS THINKING REGARDING CONVECTIVE
EVOLUTION TODAY THROUGH SUNDAY. THE MAIN THEME WILL BE MORE NUMEROUS
SHOWERS AND THUNDERSTORMS ACROSS CENTRAL LOWER MI DURING THE
AFTERNOON HOURS WITH A MORE NARROW LINE OF SCATTERED SHOWERS/STORMS
MOVING THROUGH SOUTHERN LOWER FOR THE EVENING AND LATE NIGHT HOURS.
THE SEVERE WEATHER THREAT LOOKS QUITE LOW OVERALL.
HI RES MODELS INCLUDING THE NSSL WRF AND HRRR INDICATE THE BROKEN
LINE OF SHOWERS/STORMS CURRENTLY OVER NORTHERN WI / U.P. AREA WILL
MOVE SOUTHEAST AND BE MOST WIDESPREAD ACROSS NORTHERN AND CENTRAL
LOWER MI THIS AFTERNOON WHERE H500 HEIGHTS ARE LOWEST AND SFC CONV
AS WELL AS LOW LEVEL MOISTURE FLUX CONV WILL BE MAXIMIZED. HI RES
RADAR REF SIM SUGGESTS THE CONVECTIVE EVOLUTION WILL BE A
NARROW...HORIZONTALLY DRAPED LINE OF SCATTERED SHOWERS AND A FEW
STORMS THAT MOVES FROM ROUTE 10 TO I-96 BETWEEN 18Z AND 00Z...THEN
FROM I-96 TO I-94 FROM 00Z TO 06Z.
NAM BUFKIT SOUNDINGS HAVE TRENDED VERY MUCH TOWARD GFS SOUNDINGS IN
KEEPING INSTABILITY QUITE LOW FOR ALMOST THE ENTIRE CWA...EXCEPT FOR
OUR FAR NE PORTION INCLUDING MT PLEASANT AND CLARE. THIS REGION HAS
THE BEST OPPORTUNITY FOR THUNDERSTORMS DURING THE AFTERNOON HOURS.
HOWEVER...MID LEVEL LAPSE RATES CONTINUE TO MITIGATE ANY SUBSTANTIAL
HAIL THREAT AND SFC BASED CAPE MAY ONLY BE A FEW HUNDRED J/KG...SO
EQUILIBRIUM LEVELS MAY NOT BE VERY IMPRESSIVE AND A SEVERE WEATHER
THREAT LOOKS TO BE HELD DOWN CONSIDERABLY. SO...WE`LL CONTINUE TO
WATCH FOR SOME GUSTY WINDS IN THE STRONGER STORMS BUT OVERALL THIS
EVENT LOOKS MARGINAL.
SUNDAY LOOKS DRY FOR MOST SAVE AREAS NEAR AND SOUTH OF I-94 WERE A
FEW SHOWERS MAY DEVELOP IN THE MIDST OF A H850 THERMAL AND MOISTURE
GRADIENT AND WEAK EASTERLY SFC CONV. EVEN INTO MONDAY...WITH THE
H850 THERMAL GRADIENT STILL IN PLACE AND A WEAK H500 SHORTWAVE
MOVING THROUGH DURING PEAK HEATING...SOME ISOLATED SHOWERS MAY
DEVELOP. THIS WOULD PRIMARILY BE FOR AREAS SOUTH OF A GRR TO LAN
LINE. NONE OF THIS ACTIVITY ON SUNDAY OR MONDAY LOOKS WIDESPREAD OR
SIGNIFICANT. HAVE REMOVED ALL MENTION OF THUNDER FOR BOTH OF THESE
DAYS AS MODEL SOUNDINGS DO NOT SUPPORT IT.
&&
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 323 AM EDT SAT AUG 16 2014
HIGH CONFIDENCE IN WARM SUMMERLIKE TEMPERATURES IN THE LONG TERM
PERIOD... ALTHOUGH IT LOOKS LIKE THE HOT/HUMID/UNCOMFORTABLE AIR
WITH HIGHS AROUND 90 AND DEW POINTS NEAR 70 SHOULD REMAIN JUST TO
OUR SOUTHWEST.
EARLY NEXT WEEK WE WILL BE WATCHING A SLOW MOVING SHORTWAVE WHICH
MOVES FROM NORTHERN MINNESOTA ON MONDAY TO WISCONSIN ON TUESDAY TO
LWR MI ON WEDNESDAY. A WEAK/ILL DEFINED SFC TROUGH/WARM FRONT...
ORIENTED IN A NW-SE FASHION... ACCOMPANIES/PRECEDES THIS FEATURE AS
IT IMPACTS THE UPR MIDWEST AND GRTLKS REGION DURING THE EARLY TO MID
WEEK PERIOD.
OUR BEST CHANCE OF SHOWERS/TSTMS WOULD APPEAR TO BE ON TUESDAY AND
WEDNESDAY... PARTICULARLY IN THE AFTERNOON/EVENING HOURS WITH
DIURNAL BOOST.
ONCE THE SHORTWAVE EXITS THE REGION BY THURSDAY... HEIGHT RISES
COMMENCE. HOWEVER A CHANCE OF A FEW SHOWERS AND TSTMS WILL REMAIN
SINCE THE WARM FRONT SHOULD BE SITUATED JUST TO OUR SOUTHWEST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1150 PM EDT FRI AUG 15 2014
VFR AND LIGHT WINDS WILL CONTINUE THROUGH DAYBREAK. WSW WINDS ARE
STILL EXPECTED TO INCREASE TO 10-15 KNOTS BETWEEN 13Z AND 16Z
AHEAD OF A WEAK COLD FRONT.
THE FRONT WILL CROSS MOST OF THE TAF SITES BETWEEN 00Z AND 06Z
SUNDAY. THE BEST DYNAMICS WITH THE FRONT REMAINS TO OUR NE...SO
EXPECT ANY STORMS WILL BE VERY WIDELY SCATTERED OR EVEN ISOLATED.
THE FURTHER WEST ONE GOES...THE BETTER LIKELIHOOD OF STAYING DRY.
THEREFORE HAVE REMOVE VICINITY THUNDER FOR MKG AND GRR AS THE ODDS
SEEM TOO LOW TO INCLUDE IN THESE TAFS AT THIS POINT. THE REMAINDER
OF THE TAF SITES MAY SEE VERY HIT OR MISS THUNDERSTORMS BETWEEN
21Z AND 06Z...BUT PROBABLY ONLY FOR A COUPLE HOURS AT ANY ONE
LOCATION. OUTSIDE OF ANY THUNDERSTORMS IT SHOULD REMAIN VFR...
HOWEVER AS THE FRONT SLOWS NEAR I-94 SOME MVFR CEILINGS COULD
DEVELOP TOWARD THE END OF THIS FORECAST PERIOD.
&&
.MARINE...
ISSUED AT 323 AM EDT SAT AUG 16 2014
A 2 TO 3 FOOT CHOP CAN BE EXPECTED THIS MORNING AND AFTERNOON WITH
SW WINDS PICKING UP. WINDS AND WAVES DECREASE THIS EVENING AND
EASTERLY WINDS WILL KEEP MOST WAVE ACTION AWAY FROM OUR NEARSHORE
ZONES ON MONDAY.
&&
.HYDROLOGY...
ISSUED AT 323 AM EDT SAT AUG 16 2014
NO SIGNIFICANT RAINFALL IS EXPECTED OVER THE NEXT FEW DAYS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...HOVING
SHORT TERM...HOVING
LONG TERM...MEADE
AVIATION...JK
HYDROLOGY...HOVING
MARINE...HOVING
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
131 AM EDT SAT AUG 16 2014
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 351 PM EDT FRI AUG 15 2014
WV IMAGERY AND RUC ANALYSIS INDICATED NW MID/UPPER LEVEL FLOW
THROUGH THE WRN GREAT LAKES BETWEEN A RIDGE FROM THE NRN PLAINS INTO
CNTRL ALBERTA AND A TROUGH OVER QUEBEC. AN UPSTREAM SHORTWAVE TROUGH
AND ASSOCIATED COLD FRONT WAS DIVING SE THROUGH NW ONTARIO. AT THE
SFC...LIGHT SW WINDS PREVAILED ACROSS UPPER MI AS HIGH PRES SINKS
INTO THE SRN LAKES.
TONIGHT INTO SAT...EXPECT SHRA/TSRA TO DEVELOP MAINLY AFT 06Z OVER
NORTHERN LAKE SUPERIOR THAT WILL SPREAD QUICKLY SE AS MODELS WERE IN
GOOD AGREEMENT IN BRINGING THE SHORTWAVE TROUGH WITH MODERATE 700-300
MB QVECTOR CONV...STRONG UPPER LEVEL DIV WITH THE LEFT EXIT OF A 90
KNOT 250-300 MB JET...AND AN ASSOCIATED COLD FRONT THROUGH THE NRN
GREAT LAKES. MODELS SHRTWV FORCING SUGGEST THAT THE ERN CWA WILL SEE
THE GREATEST PCPN COVERAGE/QPF WITH LIKELY TO CATEGORICAL POPS. GIVEN
POTENTIAL OF MUCAPE TO NEAR 800 J/KG... MODERATE TO STRONG DYNAMICS
AND EFFECTIVE SHEAR TO 40 KNOTS SOME EVEN MAINLY ELEVATED STORMS
ABOVE THE SHALLOW BNDRY LAYER MAY BE STRONG CAPABLE OF PRODUCING SOME
GUSTY WINDS AND SMALL HAIL. BY SAT AFTERNOON IN THE WAKE OF THE
FRONT...PCPN CHANCES SHOULD DIMINISH ACROSS THE NORTH WITH COOLER
MORE STABLE AIR MOVING IN ON LOW LEVEL NRLY FLOW. SOME DRIZZLE MAY
LINGER IN THE HIGHER TERRAIN N CNTRL IN THE MORNING IN THE WAKE OF
ANY SHOWERS EARLIER IN THE MORNING.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 348 PM EDT FRI AUG 15 2014
MAIN FCST CONCERNS IN THE LONG RANGE WL FOCUS ON TEMPS/PSBL LO CLDS
EARLY NEXT WEEK WITH NNE FLOW ON THE SRN FLANK OF DRY CNDN HI PRES
FCST TO DOMINATE. HOW QUICKLY A CHC OF SHOWERS WL RETURN TO THE FCST
IS THE CHALLENGE FOR THE MIDDLE OF NEXT WEEK.
SAT NGT...UNDER CONFLUENT NW FLOW ALF BTWN UPR RDG IN THE PLAINS AND
DEEP TROF IN QUEBEC...SFC HI PRES OVER FAR NW ONTARIO IS PROGGED TO
DRIFT SLOWLY SEWD TOWARD NRN LK SUP BY 12Z SUN. ANY LINGERING CLDS
EARLY OVER THE SCENTRAL ASSOCIATED WITH DEPARTING COLD FNT WL SHIFT
TO THE S AS THE HI PRES BUILDS TOWARD THE CWA UNDER LARGER SCALE
DNVA/DEEP LYR QVECTOR DVGC AND THE AIRMASS DRIES. IN FACT...
GUIDANCE INDICATES PWAT WL SINK TO ARND 0.5 INCH BY 12Z SUN...ABOUT
50 PCT OF NORMAL. THE MAJOR CONCERN IS THE POTENTIAL FOR SOME LO
CLDS TO DVLP...MAINLY IN THOSE AREAS OVER THE NCNTRL IMPACTED BY
UPSLOPE NNE WIND COMPONENT ON THE SRN FLANK OF THE APRCHG HI PRES.
IN FACT...THE 12Z NAM/REGIONAL CNDN/LOCAL WRF ARW FCST SDNGS SHOW A
SHALLOW...MOIST INFUSION OF COOLER AIR BLO SHARP SUBSIDENCE INVRN
BASED NEAR H9 ASSOCIATED WITH THE LARGER SCALE SUBSIDENCE/DRYING.
THESE FCSTS ARE BACKED UP BY SOME FAIRLY EXTENSIVE LO CLD COVER NOW
PRESENT OVER FAR NW ONTARIO ASSOCIATED WITH SHALLOW MOIST LYR
DEPICTED ON THE 12Z CHURCHILL MANITOBA RAOB. WL THUS INTRODUCE MORE
CLDS INTO THE FCST...MAINLY OVER THE NCENTRAL. THESE CLDS AND
EXPECTED STEADY NNE WIND WL LIMIT THE DIURNAL TEMP FALL A BIT
ESPECIALLY NEAR LK SUP OVER THE E HALF WHERE THE PRES GRADIENT IS
FCST TO BE A BIT TIGHTER. EXPECT THE LOWEST MIN TEMPS IN THE 40S
OVER THE INTERIOR W...CLOSER TO THE RDG AXIS EXTENDING FM THE HI
CENTER S TOWARD THE UPR MIDWEST AND WHERE WINDS WL BE LIGHTER AND
DOWNSLOPE WIND COMPONENT SHOULD LIMIT THE POTENTIAL FOR MORE
EXTENSIVE LO CLD.
SUN THRU MON...AS UPR RDG AXIS BUILDS INTO THE GREAT LKS FM THE W
FOLLOWING A SLOWLY EXITING QUEBEC TROF...SFC HI PRES IS FCST TO
DRIFT SLOWLY E AND INTO WRN QUEBEC BY MON AFTN. AM LO CLDS MAINLY
OVER THE NCENTRAL ON SUN MRNG SHOULD MIX OUT DURING THE AFTN WITH
DAYTIME HEATING AND THE ARRIVAL OF DRIER AIR. OTRW...THE WX OVER UPR
MI SHOULD REMAIN UNEVENTFUL WITH RDG AXIS EXTENDING WWD FM THE HI
CENTER INTO THE UPR LKS AND RELATIVELY DRY AIRMASS LINGERING. BOTH
SUN AND MON SHOULD FEATURE PLEASANT MAX TEMPS IN THE 70S AWAY FM LK
MODERATION AS H85 TEMPS ARE FCST TO TOP OUT BTWN 10-12C AND SUN AND
11-13C ON MON. MIN TEMPS ON SUN NGT WL DIP INTO THE 40S OVER THE
INTERIOR UNDER MOCLR SKIES/LIGHT WINDS DESPITE A SLOW INCRS IN PWAT
AOA 0.75 INCH.
EXTENDED...REMNANT OF CUTOFF UPR LO NOW MOVING EWD THRU THE PAC NW
IS FCST TO DRIFT SLOWLY E AND INTO THE UPR LKS ON TUE-THU NEXT WEEK
AT THE SAME TIME LARGER SCALE UPR RDG WL BE BUILDING OVER THE UPR
LKS DOWNSTREAM OF DEEPENING TROF OVER WRN CANADA/THE NW CONUS. FCST
WL INCLUDE SOME POPS AS THE SHRTWV/DEEPER MSTR INFLUENCE THE AREA...
BUT SLOWLY RISING H5 UNDER THE EXPANDING MEAN RDG SHOULD TEND TO
LIMIT THE SHOWER COVERAGE AND POPS TO THE CHC RANGE. WITH FCST H85
TEMPS NOT FAR FM 13-15C AND SOME CLDS...TEMPS SHOULD BE NOT FAR FM
THE MID/LATE AUG NORM. AS THE SHRTWV/DEEPER MSTR SLOWLY LIFT TO THE
NE AND H85 TEMPS WARM INTO THE 17-20C RANGE BY NEXT FRI UNDER THE
SLOWLY BLDG UPR RDG...EXPECT A RETURN OF ABV NORMAL TEMPS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 131 AM EDT SAT AUG 16 2014
DISTURBANCE AND ASSOCIATED COLD FRONT WILL SWEEP S ACROSS THE AREA
OVERNIGHT/EARLY THIS MORNING. INITIALLY...CONDITIONS WILL BE VFR AT
KWID/KCMX/KSAW. SHRA/ISOLD TSRA ALONG COLD FRONT WILL BE MORE LIKELY
TO AFFECT KCMX/KSAW THAN KIWD. WITH THUNDER LIKELY TO CONTINUE
DIMINISHING ALONG COLD FRONT...RETAINED ONLY A MENTION OF -SHRA
IN FCST. BEHIND FRONT...A PERIOD OF IFR CIGS IS LIKELY AT ALL
TERMINALS THIS MORNING UNDER MOIST UPSLOPE FLOW...ESPECIALLY AT KSAW
DUE TO UPSLOPE FLOW OFF THE COLDER ERN PORTION OF LAKE SUPERIOR.
IMPROVEMENT TO VFR SHOULD OCCUR AT KIWD/KCMX EARLY AFTN WHILE KSAW
MAY ONLY IMPROVE TO MVFR. VFR CONDITIONS SHOULD RETURN TO KSAW EARLY
THIS EVENING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 348 PM EDT FRI AUG 15 2014
EXPECT WINDS UNDER 20 KTS THRU NEXT WED AS A RELATIVELY WEAK PRES
GRADIENT DOMINATES THE UPPER GREAT LAKES ABOVE THE CHILLY WATERS OF
LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KC
AVIATION...ROLFSON
MARINE...KC
AREA FORECAST DISCUSSION
NWS GLASGOW MT
1032 PM MDT FRI AUG 15 2014
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SUNDAY...
10:30PM EVENING UPDATE...
WITH CONVECTION MOVING ACROSS THE CWA AND SUSTAINING ITSELF WELL
PAST DARK... IT APPEARS THERE IS MORE INSTABILITY AND EXCESS MOISTURE
TO CHEW THROUGH THAN SSEO MEMBERS ORIGINALLY HINTED AT. WITH AREAS
ACROSS THE YELLOWSTONE VALLEY HAVING RECEIVED UPWARDS OF 4 INCHES
OF STORM TOTAL RAINFALL OVER THE LAST 24 TO 48 HOURS. SOILS HAVE
BECOME SATURATED/NEAR SATURATED AND WILL HAVE DIFFICULTY
ABSORBING ANY NEW RAINFALL. INCREASED RAINFALL RATES OF 1 TO 2
INCHES FROM THE INCOMING SQUALL LINE EVIDENT ON RADAR COULD EASILY
OVERPOWER FLASH FLOOD GUIDANCE WITH BRIEF BURSTS FROM HEAVIER CELLS.
WITH BOTH WPC/HPC AND NESDIS DISCUSSIONS EXPLAINING FAVORABLE
CONDITIONS FOR SHOWER AND THUNDERSTORM DEVELOPMENT ACROSS THE
YELLOWSTONE VALLEY... HAVE DECIDE TO PUT A FLASH FLOOD WATCH OUT
FOR THE WIBAUX... DAWSON... RICHLAND... AND PRAIRIE COUNTIES. GAH
7PM EVENING UPDATE...
LINE OF THUNDERSTORMS TO THE WEST OF THE CWA ON RADAR ARE
EXPECTED TO MOVE THROUGH THE WESTERN HALF OF THE CWA BEFORE
MIDNIGHT. AREA IS STABILIZED OUT FROM AFTERNOON CONVECTION. SO, THE
OVERALL TREND FOR ENTERING THUNDERSTORMS SHOULD BE DOWNWARD
THROUGH MIDNIGHT. POPS WERE UPDATE TO ACCOUNT FOR THIS.
PATCHY FOG IS ALSO BEING HINTED AT BY THE RAP AND HRRR. NAMDNG5
DOES NOT INCLUDE THE POSSIBILITY OF FOG AND WITH SKY COVER HAVING
A HARD TIME CLEARING CONFIDENCE IS LOW AND FOG WILL BE LIMITED IN
COVERAGE. GAH
PREVIOUS SHORT TERM DISCUSSION...
MAIN CHALLENGES THIS PERIOD WAS IF AND HOW MUCH RAIN...AND IF IT
WILL FOG TONIGHT.
TWO SYSTEMS AFFECTING THE CWA. ONE IS A MCS-TYPE DISSIPATING OVER
THE SE ZONES. GFS DOING A HORRIBLE JOB OF THIS ONE TODAY AS IT/S
QPF/S WERE TOO LOW. NAM A BIT BETTER. WITH STEADY RAIN
CONTINUING...SMALL STREAM FLOOD ADVISORY FOR THIS AREA WAS EXTENDED
TILL 630 PM.
ATTENTION THEN TURNS TO THE SECOND SYSTEM...UPPER CLOSED LOW THAT IS
DRIFTING NE INTO THE NORTHERN/CANADIAN ROCKIES. THUNDERSTORMS...SOME
SEVERE...OVER WESTERN MONTANA HAVE FORMED AS A RESULT AND ARE
EXPECTED TO SPREAD INTO CENTRAL MONTANA THIS AFTERNOON. THESE STORMS
SHOULD REACH THE WESTERN ZONES AND COULD BE STRONG.
SINCE GFS DIDN/T PERFORM WELL TODAY...SIDED MORE WITH A NAM/ECMWF
BLEND WITH THINGS THROUGH MOST OF THE PERIOD. 12Z ECMWF SHOWS DECENT
QPF FOR THE SE ZONES THAT WILL HAVE TO BE WATCHED AS SOIL CONDITIONS
ARE NOW VERY WET. OTHERWISE...SHOWERS/THUNDERSTORMS WILL CONTINUE TO
BE SCATTERED ACROSS THE CWA THROUGH THE PERIOD...PROVIDING
BENEFICIAL RAINS TO MOST AREAS. TFJ
.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...
FOUND BEST CONSENSUS FOR UPDATING THE LONG TERM FORECAST THROUGH
WEDNESDAY MORNING. MAIN CONCERN FOR THIS FORECAST PERIOD IS THE
INFLUENCE OF THE LARGE-SCALE UPPER-LEVEL OPEN TROUGH WHICH
DESCENDS SOUTHWARD FROM THE CANADIAN ROCKIES AND SPREADS ACROSS
OUR BORDER WITH THEM THROUGH MOST OF NEXT WEEK. THE SMALLER-SCALE
DETAILS OF SHORT WAVE ENERGY AND TIMING AND PLACEMENT STILL NEED
TO BE WORKED OUT...BUT SOME POTENTIAL EXISTS FOR MORE WIDESPREAD
AND HEAVY RAINFALL...ESPECIALLY TOWARD THE LATTER PART OF NEXT
WEEK.
LATE MONDAY THROUGH EARLY WEDNESDAY SEEMS TO BE A RELATIVELY DRY
PERIOD OF TIME BETWEEN STORM SYSTEMS. THIS WOULD COINCIDE WITH THE
GOOD MODEL CONSENSUS REPRESENTING A SHORT WAVE RIDGE DURING THIS
TIME FRAME. BMICKELSON
PREVIOUS LONG TERM DISCUSSION...UPPER TROUGH/LOW WILL EXIT THE
AREA SUNDAY NIGHT. AS THE TROUGH MOVES TO THE EAST...A SLIGHT
CHANCE OF SHOWERS AND THUNDERSTORMS WILL LINGER IN SOME AREAS IN
SOME AREAS AS WEAK WAVES ARE POSSIBLE IN THE NW FLOW ALOFT BEHIND
THE TROUGH.
MONDAY NIGHT INTO TUESDAY MORNING WILL BE MAINLY DRY WITH THE AREA
BETWEEN SYSTEMS. AN UPPER TROUGH DIGS INTO WESTERN CANADA AND THE
PACIFIC NORTHWEST ON TUESDAY AND WEDNESDAY. THIS WILL BRING
FREQUENT SHORTWAVES WITH INCREASING CHANCES OF SHOWERS AND
THUNDERSTORMS.
THE TROUGH EXPANDS INTO MONTANA ON THURSDAY AND FRIDAY WITH DEEP
MOISTURE EXPECTED. LOOK FOR A GOOD CHANCE OF SHOWERS AND
THUNDERSTORMS. FORRESTER
&&
.AVIATION...
FLIGHT CATEGORY: MAINLY VFR EXPECTED... AS LOW AS ISOLATED IFR
POSSIBLE.
SYNOPSIS: A LARGE-SCALE STORM SYSTEM WILL SLOWLY MOVE THROUGH THE
REGION OVER THE NEXT FEW DAYS. PERIODS OF RAIN SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE. HEAVY RAIN AND IFR CONDITIONS WILL
ACCOMPANY SOME OF THE STRONGER STORMS. EXPECT MAINLY MID-LEVEL SCT CLOUDS
IN BETWEEN THE SHOWERS.
FOG: DUE TO EXCESSIVE RAINFALL... LIMITED PATCHY FOG WILL BE
POSSIBLE THROUGH THE MORNING HOURS WITH ANY CLEARING THAT OCCURS
OVERNIGHT. LOCAL RAP AND HRRR MODELS ARE HINTING AT IFR
VISIBILITIES HOWEVER NAM IS NOT SO CONFIDENCE IS TOO LOW TO
INCLUDE DIRECTLY IN TAFS YET.
AREA WINDS: VARIABLE WINDS AS OUTFLOWS FROM NEARBY STORMS WILL
IMPACT WIND SPEED AND DIRECTION.
GAH/BMICKELSON
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH SATURDAY MORNING FOR DAWSON...
PRAIRIE...RICHLAND...WIBAUX.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
501 AM EDT SAT AUG 16 2014
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND OVER THE AREA FROM OFFSHORE THROUGH
EARLY NEXT WEEK WITH A TROUGH OF LOW PRESSURE INLAND. A WEAK COLD
FRONT WILL MOVE IN FROM THE NORTH TUESDAY NIGHT...THEN RETURN
NORTH WEDNESDAY.
&&
.NEAR TERM /TODAY/...
AS OF 400 AM SATURDAY...ISOLATED SHOWER/TSTM THREAT WILL CONTINUE
ACROSS NRN HALF OF AREA THROUGH 8 AM AS ADDITIONAL ACTIVITY
DEVELOPING SOUTH OF MAIN AREA NEAR NC/VA LINE. HRRR HAS GOOD HANDLE
ON THIS ACTIVITY. ISOLATED THREAT PSBL OVER NE SECTIONS 8 AM TIL
NOON AND CONTINUED PREVIOUS FCST 20 POP THERE. SHRT WV
ENERGY...HEATING...INLAND TROF AND SEA BREEZE SUPPORT ISOLATED
SHOWERS/TSTMS INLAND OF COAST THIS AFTN. HIGH TEMPS AROUND 90 INLAND
WITH MID 80S OBX.
&&
.SHORT TERM /TONIGHT/...
AS OF 400 AM SATURDAY...ISOALATED CONVECTIVE THREAT WILL CONTINUE
INLAND THIS EVENING...WITH ANOTHER SHRT WV MOVING IN FROM W-NW.
MODELS SUPPORT ACTIVITY DIMINISHING OVERNIGHT...BUT SOME
REDEVELOPMENT PSBL ALONG COAST NEAR MORNING...THUS NO CHANGE TO
PREVIOUS FCST. MIN TEMPS FROM AROUND 70 INLAND TO MID 70S COAST.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
AS OF 330 AM SAT...LONG TERM PERIOD WILL BE DOMINATED BY WARMING
TEMPERATURE PATTERN WITH OCCASIONAL BOUTS OF SHOWERS AND
THUNDERSTORMS.
LOW LEVEL SFC FLOW RETURNS TO THE AREA THIS WEEKEND WITH INCREASING
TEMPS...THOUGH DEWPOINTS WILL BE A BIT SLOWER TO RESPOND SO STILL
EXPECTING NEAR CLIMO LOWS OVERNIGHT. CONTINUED TYPICAL SUMMERY
PATTERN ON SUNDAY WITH ISOLATED AFTERNOON THUNDERSHOWERS ALONG SEA
BREEZE FRONT.
MED/LONG RANGE MODELS IN FAIRLY GOOD AGREEMENT WITH RESPECT TO
SYNOPTIC REGIME THROUGH THE LONG TERM...WITH SLOWLY BUILDING HEIGHTS
AS MID ATLANTIC RIDGE BUILDS INTO THE DEEP SOUTH. THIS WILL BRING
HOT TEMPS AND HIGH HUMIDITY VALS AS LAYER MIX RATIOS INC TO AROUND
16 G/KG EARLY TO MID NEXT WEEK. THE REGION LOOKS TO REMAIN JUST
SOUTH OF THE STORM TRACK...THOUGH COULD BE AFFECTED BY A SYSTEM
EXPECTED TO TRAVERSE THE MID ATLANTIC REGION IN THE MON NIGHT TO TUE
TIME FRAME AND THEN AGAIN MID TO LATE WEEK.
FOR MONDAY AFTERNOON AND EVENING...HAVE AN INCREASING POP TREND AS
MODEL SUITE IS IN GOOD AGREEMENT ON A COMPACT SHORTWAVE TRAVERSING
THE MID ATLANTIC STATES...WITH SFC REFLECTION NOTED ACROSS THE
DELMARVA PENINSULA MON NIGHT. TRICKY TO PIN DOWN WHERE/WHEN
DEVELOPMENT WILL TAKE PLACE IN THIS CONVECTIVE REGIME...SO HAVE
CAPPED POPS IN THE CHANCE RANGE...LOWEST ACROSS THE SOUTHERN FA.
POTENTIAL MCS ACTIVITY COULD BRING A GOOD AMOUNT OF QPF TO PARTS OF
E NC THROUGH MON NIGHT. IN ADDITION...LAYER MIX RATIOS INC QUITE A
BIT INTO THE 17 G/KG RANGE WITH PWATS AROUND 2 INCHES. THE LOW MOVES
OFFSHORE ON TUE WITH ATTENDANT TRAILING COLD FRONT PUSHING INTO THE
AREA. KEPT CHANCE POPS TUE AS ANOTHER ROUND OF SHOWERS/STORMS COULD
AFFECT THE AREA AHEAD OF THE FRONT.
WED WILL MOST LIKELY BE A DRY DAY AS SUBSIDENCE TAKES PLACE BEHIND
EXITING LOW/SHORTWAVE BUT HAVE KEPT SLIGHT CHANCE POPS IN FCST AS
THERE IS STILL INSTABILITY PRESENT DUE TO A WARM AND MUGGY AIRMASS
IN PLACE.
THUR INTO NEXT WEEKEND...RIDGE BUILDS ACROSS THE CENTRAL CONUS
ALLOWING FOR UPR FLOW TO BECOME MORE NW ACROSS THE EASTERN SEABOARD.
THIS WILL BRING BOUTS OF NW FLOW CONVECTION WITH H85 MB BAROCLINIC
ZONE LOCATED IN THE VCNTY. HAVE PAINTED LOW CHANCE POPS FOR THIS
PERIOD AS OCNL SHORTWAVE ACTIVITY WILL AFFECT THE AREA.
TEMPS DURING THE PERIOD WILL BE QUITE WARM AND ABOVE CLIMO...WITH
THICKNESSES SUGGESTING HIGHS IN THE LOW TO OCNL MID 90S PERHAPS AT
TIMES. LOWS WILL BE MUGGY IN THE 70S.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM /THROUGH 06Z SUNDAY/...
AS OF 145 AM SATURDAY...AREA OF SHOWERS/TSTMS MOVING E ALONG NC/VA
LINE EXPECTED TO REMAIN N OF TAF SITES OVERNIGHT. PERIOD OF MVFR
VSBYS WITH LIGHT FOG/HZ 08Z-12Z MOST SITES WITH WINDS DECOUPLING
LATE. ISOLATED CONVECTIVE ACTIVITY PSBL WITH SEA BREEZE AND INLAND
TROFFING BUT COVERAGE TOO LIMITED TO MENTION IN TAFS. VFR CONDITIONS
EXPECTED TO PERSIST THROUGH THIS EVENING.
LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 330 AM SAT...GENERALLY EXPECT VFR CONDITIONS WITH ONLY
OCCASIONAL PERIODS OF SHOWERS/STORMS PRODUCING MVFR CONDITIONS
THROUGH THE LONG TERM PERIOD. MAY BE SOME LIGHT FOG/STRATUS EACH
NIGHT IN THE LONG TERM AS WINDS WILL BE LIGHT TO CALM EACH EVENING.
&&
.MARINE...
SHORT TERM /THROUGH TONIGHT/...
AS OF 400 AM SATURDAY...PRES GRADIENT BETWEEN INLAND TROF AND
OFFSHORE HIGH PRESSURE WILL TIGHTEN SLIGHTLY WITH HEATING
TODAY...RESULTING IN S-SW WINDS INCREASING TO 10-15 KT THIS AFTN AND
GRADUALLY DIMINISH OVERNIGHT. SEAS GENERALLY REMAINING AROUND 2 FT.
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 330 AM SAT...THE PERIOD BEGINS WITH SOUTH TO SW FLOW THAT INC
A BIT ON SUN AS GRADIENT INC. IN GENERAL FLOW WILL REMAIN SOUTHERLY
INCREASING TO AROUND 15 KT SUNDAY AFTERNOON THROUGH SUNDAY NIGHT.
COULD SEE A FEW 4 FOOT SEAS IN THE OUTER WATERS IN THIS TIME FRAME.
MONDAY AFTERNOON INTO TUE THE GRADIENT WILL TIGHTEN FURTHER AS AN
AREA OF LOW PRESSURE TRACKS TO OUR NORTH WITH S TO SW FLOW
INCREASING TO 15 TO 20 KT AHEAD OF A TRAILING COLD FRONT. THIS WILL
ALLOW SEAS TO BUILD TO 4 TO 5 FEET ACROSS CENTRAL AND SOUTHERN OUTER
WATERS. THE COLD FRONT PASSES THROUGH THE WATERS TUE NIGHT AND
DISSIPATES BRINGING LIGHTER WINDS RETURNING TO SOUTHERLY BY LATE
WEDNESDAY AND SEAS RETURNING TO 2 TO 3 FEET. SOME DISAGREEMENT
TOWARDS THE END OF NEXT WEEK AS GFS BRINGS GUSTY NE WINDS TO THE
AREA...HOWEVER MORE LIKELY SCENARIO IS FOR WINDS TO REMAIN S TO SW
AS HIGH PRES REMAINS IN CONTROL OF THE SE SEABOARD AND CONDITIONS TO
REMAIN SUB SCA.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JBM
NEAR TERM...JBM
SHORT TERM...JBM
LONG TERM...TL
AVIATION...JBM/TL
MARINE...JBM/TL
AREA FORECAST DISCUSSION
NWS BISMARCK ND
100 AM CDT SAT AUG 16 2014
.UPDATE...
ISSUED AT 1243 AM CDT SAT AUG 16 2014
HAVE UPGRADED...MORE SIGNIFICANT...THE THREE FLOOD ADVISORIES INTO
ONE OVERLAND FLOOD WARNING FOR THE CENTRAL PART OF WESTERN NORTH
DAKOTA. HAVE ALSO CANCELED THE FLASH FLOOD WATCH AS FLOODING IS
NOT OF THE FLASH VARIETY AND WILL NOT BE THE REST OF THE NIGHT.
UPDATE ISSUED AT 954 PM CDT FRI AUG 15 2014
AN UPPER LEVEL MESO-LOW CONTINUES TO GENERATE MODERATE RAINFALL
ACROSS WEST-CENTRAL NORTH DAKOTA. RAINFALL AMOUNTS UNDER THE
HIGHEST REFLECTIVITIES HAVE TOTALED GENERALLY BETWEEN 1 AND 2
INCHES NEAR GRASSY BUTTE AND FAIRFIELD. OUTFLOW FROM
THUNDERSTORMS OVER NORTHEASTERN MONTANA IS RACING SOUTHEASTWARD
TOWARDS THIS AREA OF PERSISTENT RAIN SHOWERS...AND WILL LIKELY
ENHANCE LIFT AND RAINFALL INTENSITY DURING THE NEXT FEW HOURS. AS
A RESULT...WILL MAINTAIN THE FLASH FLOOD WATCH FOR THIS UPDATE.
FOCUS THEN SHIFTS UPSTREAM WHERE A LARGER SHORTWAVE IS GENERATING
A LINE OF THUNDERSTORMS ACROSS CENTRAL MONTANA. BASED ON ITS
CURRENT TRAJECTORY...THESE THUNDERSTORMS SHOULD CROSS INTO EXTREME
WESTERN NORTH DAKOTA AROUND 10Z. ALTHOUGH IT IS FORECAST TO BRING
ADDITIONAL RAINFALL WEST...IT SHOULD KICK THE MESO-LOW OUT OF
WEST-CENTRAL NORTH DAKOTA INTO SOUTH DAKOTA.
UPDATED THE SENSIBLE WEATHER ELEMENTS BASED ON CURRENT OBS/TRENDS.
THE UPDATED PRODUCTS WILL BE OUT SHORTLY.
UPDATE ISSUED AT 556 PM CDT FRI AUG 15 2014
THE LATEST MODEL GUIDANCE CONTINUES TO PROG THE HEAVY RAIN
POTENTIAL CONTINUING OVER SOUTHWESTERN NORTH DAKOTA TONIGHT. MOST
MODELS ARE A LITTLE TOO FAR SOUTH WITH THE ONGOING ACTIVITY...WITH
THE 12Z GEM ACTUALLY DOING A PRETTY GOOD JOB PAINTING THE HIGHEST
QPF WHERE THE CURRENT CONVECTION IS LOCATED.
FOR THE UPDATE...ADJUSTED POPS UPWARDS BASED ON CURRENT RADAR OBS
AND EXTRAPOLATED THE HIGHER POPS SOUTHEASTWARD THROUGH THE
OVERNIGHT HOURS...BASED ON THE 12Z GEM SOLUTION. WILL KEEP THE
CURRENT FLASH FLOOD WATCH AS IS FOR THIS UPDATE.
ALSO EXTENDED THE FLOOD ADVISORY FOR BILLINGS...SOUTHWESTERN
MCKENZIE...AND GOLDEN VALLEY COUNTIES UNTIL 530 AM CDT. THE LATEST
RAINFALL REPORT FROM BEACH IS 4.6 INCHES...AND IT IS STILL
RAINING. OVERLAND FLOODING CONTINUES TO BE AN ISSUE WITH SOME
COUNTY ROADS UNDER WATER.
THE UPDATED GRIDDED AND TEXT PRODUCTS WILL BE OUT SHORTLY.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 549 PM CDT FRI AUG 15 2014
HEAVY RAINFALL AND ASSOCIATED FLASH FLOODING WILL HIGHLIGHT THE
SHORT TERM FORECAST.
EXTENDED THE FLASH FLOOD WATCH THROUGH 12 UTC SATURDAY ACROSS THE
SOUTHWEST. THE 12 UTC WRF-ARW/NMM...INCOMING 18 UTC NAM AND 16-17
UTC HRRR ITERATIONS CONTINUE TO FOCUS RAIN SHOWERS AND
THUNDERSTORMS WITH PROLONGED MODERATE TO HEAVY RAINFALL ACROSS THE
SOUTHWEST AND FAR SOUTH CENTRAL LATE THIS AFTERNOON AND INTO THE
EARLY EVENING IN ASSOCIATION WITH THE UPPER LEVEL LOW EVIDENT ON
WATER VAPOR ACROSS THE SOUTHWEST. THESE SOLUTIONS WANE CONVECTION
A BIT AFTER SUNSET...THEN REDEVELOP THUNDERSTORMS ACROSS THE WEST
REINVIGORATED BY INCREASING UPPER LEVEL DIFFLUENCE AND IMPULSES
EJECTING OUT OF THE PACIFIC NORTHWEST CLOSED LOW. THIS IS IN
AGREEMENT WITH NESDIS SATELLITE PRECIPITATION ESTIMATES AND
HIGHLIGHTS FOR HEAVY RAINFALL TONIGHT. GIVEN THIS REGENERATION OF
SLOW MOVING STORMS LATE TONIGHT OVER ALREADY SATURATED AREAS WITH
PWATS NEAR 1.75 INCHES...THE EXTENSION OF THE WATCH IS WARRANTIED.
THE 12 UTC WRF-ARW/NMM DO HIGHLIGHT SIOUX AND EMMONS COUNTIES LATE
TONIGHT AS WELL FOR HEAVY RAIN...AND THIS WILL HAVE TO BE
MONITORED. ADDITIONAL SCATTERED THUNDERSTORMS WITH HEAVY RAIN WILL
CONTINUE ACROSS MUCH OF THE AREA SATURDAY AS THE PACIFIC NORTHWEST
UPPER LEVEL LOW BEGINS TO PROPAGATE INTO THE NORTHERN PLAINS. WILL
ALLOW FURTHER SHIFTS TO EVALUATE IF A FLASH FLOOD WATCH IS NEEDED.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 549 PM CDT FRI AUG 15 2014
THE MAIN FORECAST ISSUE IN THE EXTENDED PERIOD WILL CONTINUE TO BE
THE THREAT OF HEAVY RAINFALL THROUGH THE WEEKEND AND INTO EARLY NEXT
WEEK. DETERMINISTIC MODELS ARE IN REASONABLE AGREEMENT IN BRINGING
AN UPPER LEVEL LOW CURRENTLY OVER EASTERN WASHINGTON...EAST ALONG
THE INTERNATIONAL BORDER...TO THE EASTERN DAKOTAS BY MONDAY
AFTERNOON. ALTHOUGH THE THREAT OF SEVERE WEATHER WILL BE LOW. WE
WILL STILL NEED TO MONITOR THE THREAT OF HEAVY RAINFALL...
PARTICULARLY IN THE SUNDAY NIGHT INTO EARLY MONDAY PERIOD.
PERHAPS A BRIEF DRY PERIOD TUESDAY INTO EARLY WEDNESDAY. BUT MODELS
THEN START SHIFTING INTO MORE OF A SOUTHWEST FLOW BY MID TO LATE
WEEK BRINGING INCREASED PRECIPITATION CHANCES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1243 AM CDT SAT AUG 16 2014
WIDESPREAD MVFR CIGS AND VIS WITH LCL IFR VIS IN HEAVIER PRECIP WILL
CONTINUE THROUGH THIS MORNING OVER MUCH OF WESTERN NORTH DAKOTA AS
SHRA/TSRA CONTINUE TO MOVE THROUGH THE AREA. PRECIPITATION WILL
SLOWLY DEVELOP TOWARDS THE EAST TODAY POSSIBLY BRINGING VISIBILITY
RESTRICTIONS INTO CENTRAL NORTH DAKOTA.
&&
.HYDROLOGY...
ISSUED AT 1243 AM CDT SAT AUG 16 2014
IN THE AREA FROM DICKINSON...TO JUST SOUTH OF WILLISTON...OVERLAND
FLOODING CONTINUES AND HAS WORSENED AS YARDS AND FIELDS HAD
STANDING WATER...AND NOW SOME SMALLER CREEKS WERE OVERFLOWING
THEIR BANKS IN DUNN AND STARK COUNTIES. TRAVEL ALERTS HAVE BEEN
ISSUED BY COUNTY OFFICIALS AND ROAD RESTRICTIONS HAVE BEEN PLACED
ON WITH RESPECT TO WEIGHT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JPM
SHORT TERM...AYD
LONG TERM...TWH
AVIATION...JJS
HYDROLOGY...JPM
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1146 PM CDT FRI AUG 15 2014
.UPDATE...
ISSUED AT 1145 PM CDT FRI AUG 15 2014
ISOLATED STORMS CONTINUE TO FIRE ALONG A FRONTAL BOUNDARY MOVING
SLOWLY THROUGH THE NORTHERN COUNTIES. RAP SEEMS TO HAVE A PRETTY
GOOD HANDLE ON CURRENT CONVECTION...SO CONTINUED THE TREND OF SOME
ISOLATED ACTIVITY THROUGH THE NEXT FEW HOURS...BUT THE MAIN SHOW
WILL BE LATER TOMORROW AS THE WEAK UPPER SYSTEM MOVES
SOUTHEASTWARD OUT OF WESTERN ND.
UPDATE ISSUED AT 946 PM CDT FRI AUG 15 2014
STORMS MOVING INTO PEMBINA COUNTY A FEW HOURS AGO DISSIPATED...BUT
MORE CONVECTION JUST NORTH OF THE CANADIAN BORDER WILL CONTINUE TO
MOVE DOWN INTO THE FORECAST AREA. BUMPED UP POPS FOR A WHILE IN
THE NORTHERN RED RIVER VALLEY...BUT DID NOT GO TOO HIGH AS THERE
CONTINUES TO BE A DECREASING TREND. THERE IS A DECENT AMOUNT OF
ELEVATED CAPE BUT SHEAR IS LACKING SO DO NOT THINK ANYTHING WILL
BE SEVERE. SHORT RANGE MODELS HAVE PRECIP MOVING TOWARDS GFK BY
06Z BUT SEEM TO BE OVERDOING CURRENT CONVECTION SO WILL JUST KEEP
LOW POPS AND AN EYE ON IT FOR NOW.
UPDATE ISSUED AT 653 PM CDT FRI AUG 15 2014
ADJUSTED POPS FOR THIS EVENING AS THE RAIN OVER WESTERN ND DOES
NOT APPEAR TO BE MOVING ANY FURTHER EAST. BEST CHANCES FOR
ISOLATED STORMS WILL CONTINUE TO BE IN THE NORTHERN CWA AS A COLD
FRONT COMES DOWN. THINK THAT THE SOUTH WILL STAY DRY UNTIL THE
EARLY MORNING HOURS. WILL CONTINUE TO KEEP LOWS IN THE 60S.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 300 PM CDT FRI AUG 15 2014
THUNDER CHANCES WILL BE THE MAIN CHALLENGE. THIS FA WILL BE
BETWEEN AN UPPER CIRCULATION TO THE WEST AND ANOTHER UPPER WAVE TO
THE EAST...AND MOST AREAS SHOULD REMAIN DRY. HOWEVER...THERE WILL
BE CHANCES FOR ISOLD/SCATTERED ACTIVITY.
FOR THE REMAINDER OF THIS AFTERNOON INTO THE EVENING...THE
AIRMASS HAS BECOME UNSTABLE...WITH MLCAPE 1500-2000 J/KG ALONG AND
WEST OF THE VALLEY. CURRENT LAPS ANALYSIS INDICATES MLCIN 10-20
J/KG...AND NOT SURE THERE WILL BE ENOUGH HEATING/FORCING FOR ANY
THUNDER DEVELOPMENT. THE BEST CHANCE FOR ISOLD ACTIVITY WILL
LIKELY BE THIS EVENING NEAR THE INTERNATIONAL BORDER AS THE COLD
FRONT (ASSOCIATED WITH THE UPPER WAVE TO THE EAST) PROPAGATES
SOUTHWARD.
THE NEXT BEST CHANCE FOR PRECIP WILL BE ACROSS THE SOUTHERN FA ON
SATURDAY AS THE UPPER CIRCULATION ACROSS SOUTHWESTERN NORTH DAKOTA
PROPAGATES TO THE SOUTHEAST. DEEP LAYER SHEAR WILL BE VERY
WEAK...AND DO NOT EXPECT ANY STRONG STORMS (ALTHOUGH THE STORM
MOTIONS ARE EXPECTED TO BE RELATIVELY SLOW AND LOCALLY HEAVY
RAINFALL MAY BE POSSIBLE).
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 300 PM CDT FRI AUG 15 2014
SUNDAY-MONDAY...MUCH OF SUNDAY WILL BE DRY. THEN...THE UPPER LOW
ACROSS THE PAC NW WILL PROPAGATE THROUGH THE REGION SUNDAY NIGHT
INTO MONDAY. THIS WILL LEAD TO A HIGHER PROBABILITY THAT MOST
PLACES WILL EXPERIENCE MEASURABLE PRECIPITATION. CURRENT MODELS
RUNS ARE RELATIVELY WEAK WITH DEEP LAYER SHEAR AND
INSTABILITY...AND THE SEVERE THREAT WOULD APPEAR TO BE TOWARD THE
LOWER END.
MONDAY NIGHT-FRIDAY...THIS PARTICULAR SUITE OF THE VARIOUS MODELS
ARE IN FAIR AGREEMENT. A DEPARTING UPPER LOW WITH ATTENDANT
SURFACE REFLECTION SHOULD BRING AN END TO PRECIPITATION BY TUESDAY
AFTERNOON. AS LOW MOVES TO THE EAST EXPECT A BROAD TROUGH TO FORM
OVER THE NORTHWEST U.S. THIS SHOULD HELP SPLIT THE FLOW OVER THE
CWFA MID WEEK.
BASED ON THE BRIEF SPLIT FLOW THAT FORMS...THE BULK OF WEDNESDAY
SHOULD BE PRECIPITATION FREE. WAA DRIVEN TSRA BEGIN TO MOVE INTO THE
WESTERN HALF OF THE CWFA AFTER 00Z THU AND OVERSPREAD THE REGION
LINGERING INTO FRIDAY.
TEMPERATURES SHOULD GENERALLY BE NEAR MID AUGUST MEDIANS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1145 PM CDT FRI AUG 15 2014
VFR CONDITIONS WILL CONTINUE...ALTHOUGH KBJI MAY DROP DOWN TO MVFR
FOR A BRIEF PERIOD DURING THE MORNING. WINDS WILL SHIFT AROUND TO
THE NORTH AS A COLD FRONT COMES DOWN INTO THE AREA. THINK THAT
CIGS WILL BE MOSTLY 4000-6000 FT BEHIND THE FRONT BUT WILL HAVE TO
KEEP AN EYE OUT FOR SOME MVFR. BY AFTERNOON...CIRRUS WILL BE THE
MAIN CLOUD COVER AND SOME CONVECTION WILL BE POSSIBLE OVER THE
SOUTHERN AND WESTERN FORECAST AREA AS AN UPPER LEVEL DISTURBANCE
MOVES SOUTH. TOO SOON TO TELL IF IT WILL IMPACT KFAR OR ANY OF THE
OTHER TAF SITES...SO WILL LEAVE CONVECTION OUT FOR NOT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...TG
LONG TERM...EWENS/TG
AVIATION...JR
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
253 AM CDT SAT AUG 16 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 253 AM CDT SAT AUG 16 2014
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING OVER THE SOUTHWESTERN U.S....AN UPPER LOW IN NORTHERN
IDAHO...SHORTWAVES OVER THE DAKOTAS AND THE KANSAS CITY AREA...AND A
DEEP UPPER TROUGH OVER EASTERN CANADA INTO THE NORTHEAST U.S..
WITHIN THIS TROUGH...A FAIRLY POTENT SHORTWAVE WAS APPROACHING LAKE
SUPERIOR. THE FORECAST AREA LIES IN THE NORTHWEST FLOW ON THE
WESTERN EDGE OF THE TROUGH...BUT STILL NEAR THE INFLECTION POINT
FAVORING SUBSIDENCE AND HIGH PRESSURE AT THE SURFACE. THUS...ONLY
SOME SCATTERED CIRRUS CLOUDS HAVE BEEN TRACKING ACROSS THE FORECAST
AREA. 15.00Z MODELS DEFINITELY OVER-FORECAST THE PRECIPITABLE
WATER...INSTEAD OF BEING 1.5-1.75 INCHES IS ONLY 1-1.25 INCHES PER
GOES DERIVED IMAGERY. SURFACE DEWPOINTS ARE HIGHER...THOUGH...WHICH
WITH RADIATIONAL COOLING HAS LED TO SOME BR AND LOW STRATUS
DEVELOPMENT. THE NEAREST AREAS WHERE PRECIPITATION IS OCCURRING ARE
SOUTH OF I-80 IN IOWA ASSOCIATED WITH THE KANSAS CITY SHORTWAVE...
OVER THE CENTRAL DAKOTAS WITH THE SHORTWAVE THERE...AND THE MN
ARROWHEAD INTO UPPER MICHIGAN AHEAD OF THE APPROACHING SHORTWAVE.
THIS LAST PRECIPITATION AREA IS ALSO SUPPORTED BY A SURFACE COLD
FRONT TRACKING WITH IT.
500MB HEIGHTS ARE PROGGED TO RISE OVER THE NEXT 24 HOURS IN RESPONSE
TO THE UPPER LOW OVER NORTHERN ONTARIO PUSHING EAST INTO SOUTH
CENTRAL SASKATCHEWAN. TYPICALLY WHEN SEEING HEIGHT RISES ONE WOULD
EXPECT A WARM ADVECTION PATTERN. HOWEVER...IN THIS CASE...THE
SHORTWAVE APPROACHING LAKE SUPERIOR WILL DROP INTO THE EASTERN GREAT
LAKES THIS EVENING...SENDING ITS ASSOCIATED COLD FRONT THROUGH THE
FORECAST AREA.
MUCH OF THIS MORNING CONTINUES TO LOOK DRY AS ANY SHOWER ACTIVITY
ASSOCIATED WITH THE KANSAS CITY SHORTWAVE STAYS JUST TO THE
SOUTH...AS DEPICTED IN THE LATEST RAP/HRRR DATA. ANY FOG/STRATUS
SHOULD DISSIPATE WITHIN A FEW HOURS AFTER SUNRISE. HEADING INTO THE
AFTERNOON...DETERMINISTIC AND HIGH RESOLUTION MODELS REMAIN IN GOOD
AGREEMENT THAT THIS COLD FRONT WILL HELP INITIATE CONVECTION NORTH
OF I-94. THIS IS A RESULT TOO OF TEMPERATURES CLIMBING INTO THE 80S
FROM 850MB TEMPS AROUND 16C...AS WELL AS DEWPOINTS CLIMBING INTO THE
MID TO UPPER 60S...COMBINING TO PRODUCE MLCAPES OF 1000-2000 J/KG.
THIS CAPE IS OVERALL SKINNY AND 0-6 KM/0-3KM SHEAR ARE 20 KT OR LESS
WHICH WILL LIMIT SEVERE WEATHER POTENTIAL. HOWEVER...EQUILIBRIUM
LEVELS ARE NEAR 40000 FT AND WARM CLOUD DEPTHS APPROACH 4000
METERS...SO THE STORMS ARE LIKELY TO PRODUCE HEAVY RAIN. THE AMOUNT
OF CONVECTION SEEMS SCATTERED AT BEST SINCE THE BETTER FRONTAL
CONVERGENCE AND DYNAMIC FORCING ARE FARTHER EAST...MORE TOWARDS
LOWER MICHIGAN CLOSER TO THE SHORTWAVE TRACK.
CONVECTION NORTH OF I-94 IN THE AFTERNOON THEN LOOKS TO DROP SOUTH
IN THE EVENING WITH THE COLD FRONT. HOWEVER...COOLING TEMPERATURES
FROM LOSS OF DAYTIME HEATING AND THE FACT LITTLE CONVERGENCE EXISTS
ON THE FRONT WILL LIKELY RESULT IN A DIMINISHING TREND TO THE
CONVECTION. THERE MAY NOT BE MUCH LEFT AFTER 06Z AS THE 16.00Z GFS
SUGGESTS. IN THE WAKE OF THE COLD FRONT...IT APPEARS A LOW STRATUS
DECK MAY END UP DEVELOPING AND ADVECTING SOUTHWESTWARD. BASED ON
FORECAST SOUNDINGS...LOCATIONS SOUTHWEST OF I-94 APPEAR TO HAVE THE
GREATEST CHANCE OF SEEING THIS STRATUS DECK. COOLING 925MB TEMPS ON
THE EASTERLY FLOW SHOULD RESULT IN A COOLER NIGHT...ESPECIALLY IN
CENTRAL WI.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 253 AM CDT SAT AUG 16 2014
MAIN ISSUE ON SUNDAY RELATES TO THE SHORTWAVE OVER THE DAKOTAS
CURRENTLY. THE 16.00Z GFS/NAM TRACK THIS SHORTWAVE ACROSS MN DURING
THE DAY...WHICH HELPS PRODUCE SOME SHOWERS AND EMBEDDED STORMS
MOSTLY JUST WEST OF THE FORECAST AREA. PART OF THE REASON THIS
PRECIPITATION DOESNT DEVELOP FARTHER EAST IS A DRY EASTERLY FLOW
PROVIDED BY HIGH PRESSURE BUILDING OVER UPPER MI IN THE WAKE OF
TONIGHTS COLD FRONT. ITS POSSIBLE SOME OF THE SHOWER ACTIVITY
CREEPS INTO SOUTHEAST MN...BUT CONFIDENCE IS NOT HIGH ENOUGH TO PUT
ANY CHANCES IN YET. OTHERWISE...SUNDAY LOOKS COOLER THAN TODAY DUE
TO THE EASTERLY FLOW...MORNING STRATUS AND 925MB TEMPS ABOUT 4C
COOLER.
SUNDAY NIGHT NOW POSES SOME FORECAST CHALLENGE. 16.00Z ECMWF IS
SLOWER THAN THE GFS/NAM TRACKING THE SHORTWAVE EASTWARD OUT OF
MN...AND IN FACT HAS THE WAVE MOVE RIGHT ACROSS THE FORECAST AREA.
ADDITIONALLY...IN THE ECMWF...A SURGE OF 850MB MOISTURE TRANSPORT
ACCOMPANIES THE WAVE...HELPING TO PRODUCE SHOWERS AND STORMS ACROSS
MUCH OF THE AREA AND ESPECIALLY AFTER 06Z. NOW...THE 16.00Z GFS ALSO
DEPICTS AN INCREASE OF 850MB MOISTURE TRANSPORT AND PRECIPITATION...
BUT ITS MORE OVER NORTHWEST SECTIONS OF THE ARE AND IN RESPONSE TO
UPPER TROUGHING COMING INTO THE DAKOTAS. IN ANY EVENT...GIVEN THAT
THESE 2 MODELS ARE PRODUCING PRECIPITATION...FELT A NEED TO INCLUDE
20 PERCENT CHANCES IN FOR AT LEAST THE WEST HALF OF THE FORECAST
AREA. THESE MAY NEED TO BE INCREASED IF MODEL TRENDS CONTINUE.
MONDAY THROUGH TUESDAY...AND IN PARTICULARLY MONDAY NIGHT...STILL
REMAIN THE BEST CHANCE FOR WIDESPREAD RAIN. ALL MODELS ARE IN
AGREEMENT THAT THE CURRENT UPPER LOW OVER NORTHERN IDAHO...AND
ASSOCIATED GENERAL UPPER TROUGHING...WILL MOVE THROUGH THE FORECAST
AREA DURING THIS TIMEFRAME. A SURGE OF 1.5 INCH PRECIPITABLE WATER
COMBINED WITH DPVA FORCING FROM THE TROUGH...AS WELL AS INSTABILITY
SHOULD RESULT IN SHOWERS AND STORMS. MONDAY NIGHT SEEMS TO BE THE
BEST JUXTAPOSITION OF THE AFOREMENTIONED PARAMETERS AND THUS HIGHEST
CHANCES AROUND 70 PERCENT ARE CENTERED THERE. 0-6KM/0-3KM SHEAR
PROGGED LESS THAN 20 KT SO BRIEF HEAVY RAIN WOULD LIKELY BE THE MAIN
CONCERN WITH THE STORMS.
THE REST OF NEXT WEEK FEATURES THE UPPER LOW AND TROUGHING LIFTING
OUT OF THE REGION ON WEDNESDAY...FOLLOWED BY RIDGING BUILDING UP
ACROSS THE PLAINS AS TROUGHING REFORMS OVER THE PACIFIC NORTHWEST.
THIS SETUP IS FAVORABLE FOR BOTH WARM AND MOIST AIR ADVECTION...AND
AS SUCH MODELS CONTINUE TO OSCILLATE ON WHERE AND WHEN STORMS COULD
FIRE ON THE NOSE OF THIS ADVECTION. THEREFORE...FORECAST DEPICTS A
CONSENSUS WITH 20-40 PERCENT CHANCES FROM WEDNESDAY THROUGH FRIDAY.
THERE ARE SOME INDICATIONS WEDNESDAY COULD PAN OUT DRY...THUS LOWEST
CHANCES ARE CENTERED THEN. SEVERE WEATHER POTENTIAL WISE...IF THE
ECMWF PANS OUT...THERE COULD BE A SHOT FOR SOME ON THURSDAY. PLENTY
OF UNCERTAINTY OUT THERE...THOUGH. TEMPERATURES LOOK TO GRADUALLY
INCREASE EACH DAY WITH MOST DAYS AT OR ABOVE NORMAL. IT SHOULD BE
NOTED THAT IF ANY DAY ENDS UP WITH LESS CLOUDS...TEMPERATURES COULD
END UP WARMER THAN FORECAST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1144 PM CDT FRI AUG 15 2014
MAIN CONCERN CONTINUES TO BE WHETHER FOG WILL FORM OVERNIGHT. THE
HIGH LEVEL CLOUDS HAVE SHIFTED SOUTH OF THE AREA WHILE THE
MAJORITY OF THE CLOUDS APPROACHING FROM THE NORTH LOOK LIKE THEY
WILL GO EAST OF THE AREA. WINDS HAVE ALREADY GONE LIGHT SETTING UP
GOOD RADIATIONAL COOLING CONDITIONS. TEMP/DEW POINT DEPRESSIONS
FOR THE MOST PART ARE LESS THAN 5 DEGREES. THE 16.00Z NAM AND
16.03Z RAP CONTINUE TO SHOW A LAYER OF STRONGER WINDS ABOVE THE
SURFACE WHICH IS CONFIRMED BY AREA VWP WINDS. HOWEVER...THESE
MODELS NOW SUGGEST THESE WINDS WILL DIMINISH LATE TONIGHT SETTING
UP A SHORT PERIOD OF VERY FAVORABLE CONDITIONS FOR FOG. HAVE THUS
INCLUDED A PERIOD OF IFR CONDITIONS WITH THE FOG AT BOTH TAF SITES
FOR LATE TONIGHT INTO SATURDAY MORNING. ONCE THE FOG
LIFTS...EXPECT TO SEE VFR CONDITIONS FOR THE REMAINDER OF THE
PERIOD. THE COLD FRONT THAT COMES IN FROM THE NORTH SATURDAY
EVENING LOOKS TO HAVE LITTLE TO NO SUPPORT WITH IT WITH BOTH THE
NAM AND 16.00Z GFS SHOWING ONLY SOME HIGH LEVEL CLOUDS WITH IT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1144 PM CDT FRI AUG 15 2014
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 341 PM CDT FRI AUG 15 2014
AT 3 PM...A BAND OF SHOWERS EXTENDED FROM SOUTH-CENTRAL IOWA
SOUTHEAST INTO SOUTHEAST IOWA. THIS IS ASSOCIATED WITH MODERATE TO
STRONG 900 TO 500 MB FRONTOGENETIC FORCING AND WEAK TO MODERATE
305K ISENTROPIC LIFT.
FOR TONIGHT...THE MESO AND DETERMINISTIC MODELS ARE IN GOOD
AGREEMENT THAT THE TROUGH OF LOW PRESSURE...CURRENTLY OVER EASTERN
SOUTH DAKOTA AND EASTERN NEBRASKA WILL MOVE EAST AND SOUTHEAST
THROUGH IOWA. THE MESO MODELS SHOW THAT THE MODERATE TO STRONG 900
TO 500 MB FRONTOGENESIS WILL REMAIN SOUTHWEST OF THE AREA THIS
EVENING...AND SOUTH OF THE AREA OVERNIGHT. AS A LOW DEVELOPS OVER
IOWA OVERNIGHT...THE 305K ISENTROPIC LIFT INCREASES DRAMATICALLY
ACROSS SOUTH-CENTRAL IOWA. THIS WILL LIKELY KEEP A MAJORITY OF
THE SHOWERS AND THUNDERSTORMS SOUTH OF THE AREA. HOWEVER WITH THE
NAM SOLUTIONS SUGGESTING A SLIGHTLY FURTHER NORTH TRACK OF THIS
SYSTEM KEPT A SLIGHT CHANCE OF PRECIPITATION IN FLOYD...
CHICKASAW...FAYETTE...AND CLAYTON COUNTIES IN NORTHEAST IOWA AND
GRANT COUNTY IN SOUTHWEST WISCONSIN BETWEEN 2 AM AND 10 AM
SATURDAY.
ANOTHER ISSUE FOR EARLY SATURDAY MORNING IS THE POTENTIAL FOR
AREAS OF FOG TO DEVELOP. BOTH THE NAM AND GFS BUFKIT SOUNDINGS
SHOW THAT THERE WILL BE A DRAMATIC INCREASE IN THE MOISTURE BELOW
925 MB AFTER 3 AM. THE WINDS IN THIS LAYER ARE LESS THAN 10 KNOTS
WHICH WOULD BE CONDUCIVE FOR THE DEVELOPMENT OF FOG. THE NUMERICAL
GUIDANCE SUGGESTS THAT THIS FOG COULD BECOME DENSE. ONE THING THAT
MIGHT DETER THE DENSE FOG DEVELOPMENT IS THE 10 TO 15 KNOT WINDS
BETWEEN 950 AND 900 MB. FOR THE TIME BEING...JUST ADDED AREAS OF
FOG TO THE GRIDS.
ON SATURDAY AFTERNOON...THE MODELS CONTINUE TO SHOW THAT A
CANADIAN COLD FRONT WILL MOVE SOUTH INTO NORTH-CENTRAL WISCONSIN
DURING THE MID TO LATE AFTERNOON. ML CAPES AHEAD OF THIS FRONT
CLIMB INTO THE 1000 TO 1500 J/KG RANGE. HOWEVER BOTH THE 0-3 KM
AND 0-6 KM SHEAR IS NOT THAT FAVORABLE FOR THE DEVELOPMENT OF
SEVERE WEATHER.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 341 PM CDT FRI AUG 15 2014
ON SATURDAY EVENING...THE ML CAPES ALONG AND AHEAD OF COLD FRONT
MOVING THROUGH THE INTERSTATE 90 AND 94 CORRIDORS QUICKLY
DECREASES WITH THE LOSS OF DIURNAL HEATING. AS THIS OCCURS...THE
SHOWER AND THUNDERSTORM ACTIVITY WILL BECOME ISOLATED.
ON SUNDAY AND SUNDAY NIGHT...A CANADIAN HIGH PRESSURE WILL BRING
DRIER AIR INTO THE REGIONS. ORIGINALLY THE NAM KEPT THE DEW POINTS
IN THE LOWER AND MID 60S...BUT IT HAS NOW SHIFTED TOWARD THE DRIER
GFS AND ECMWF SOLUTIONS OF YESTERDAY. THE COMBINATION OF LIGHT
WINDS AND DEW POINTS IN THE MID AND UPPER 40S WILL ALLOW
TEMPERATURES TO ONCE AGAIN DROP INTO THE MID AND UPPER 40S ON
MONDAY MORNING. DUE TO THIS...WENT COLDER THAN THE SUPERBLEND.
FROM MONDAY AFTERNOON INTO TUESDAY NIGHT...THE 15.12Z MODELS
CONTINUE TO AGREE WITH PREVIOUS MODEL RUNS THAT A SHORT WAVE
TROUGH /THIS SYSTEM IS CURRENTLY LOCATED OVER THE PACIFIC
NORTHWEST/ WILL MOVE THROUGH THE REGION. WITH MODERATE 850 MB
MOISTURE TRANSPORT AHEAD OF THIS SYSTEM...THIS LOOKS TO BE OUR
BEST CHANCE FOR WIDESPREAD RAIN ACROSS THE AREA.
FROM WEDNESDAY INTO FRIDAY...THE MODELS CONTINUE TO STRUGGLE WITH
THE TIMING OF SHORT WAVE TROUGH MOVING THROUGH THE REGION. IN
ADDITION...THEY KEEP TRYING TO DEVELOP A TROUGH OVER THE WESTERN
UNITED STATES WHICH WOULD PRODUCE ZONAL OR SOUTHWEST FLOW ACROSS
OUR AREA. HOWEVER WITH THE ANOMALOUS WARM WATER LOCATED OFF THE
WEST COAST OF CANADA /LIKE MUCH OF LAST WINTER/...THE PATTERN THAT
THE MODELS ARE TRYING TO TREND TOWARD IS NOT THAT FAVORABLE...SO A
BIT LEARY OF THE GFS AND ECMWF SOLUTIONS DURING THIS TIME FRAME.
THIS INCLUDES THE VERY WARM TEMPERATURES THAT THESE MODELS ARE
INDICATING FOR THE END OF NEXT WEEK. A MORE FAVORABLE PATTERN
WOULD BE FOR A TROUGH OVER THE GREAT LAKES AND OHIO VALLEYS WHICH
WOULD KEEP US IN A NORTHWEST FLOW ALOFT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1144 PM CDT FRI AUG 15 2014
MAIN CONCERN CONTINUES TO BE WHETHER FOG WILL FORM OVERNIGHT. THE
HIGH LEVEL CLOUDS HAVE SHIFTED SOUTH OF THE AREA WHILE THE
MAJORITY OF THE CLOUDS APPROACHING FROM THE NORTH LOOK LIKE THEY
WILL GO EAST OF THE AREA. WINDS HAVE ALREADY GONE LIGHT SETTING UP
GOOD RADIATIONAL COOLING CONDITIONS. TEMP/DEW POINT DEPRESSIONS
FOR THE MOST PART ARE LESS THAN 5 DEGREES. THE 16.00Z NAM AND
16.03Z RAP CONTINUE TO SHOW A LAYER OF STRONGER WINDS ABOVE THE
SURFACE WHICH IS CONFIRMED BY AREA VWP WINDS. HOWEVER...THESE
MODELS NOW SUGGEST THESE WINDS WILL DIMINISH LATE TONIGHT SETTING
UP A SHORT PERIOD OF VERY FAVORABLE CONDITIONS FOR FOG. HAVE THUS
INCLUDED A PERIOD OF IFR CONDITIONS WITH THE FOG AT BOTH TAF SITES
FOR LATE TONIGHT INTO SATURDAY MORNING. ONCE THE FOG
LIFTS...EXPECT TO SEE VFR CONDITIONS FOR THE REMAINDER OF THE
PERIOD. THE COLD FRONT THAT COMES IN FROM THE NORTH SATURDAY
EVENING LOOKS TO HAVE LITTLE TO NO SUPPORT WITH IT WITH BOTH THE
NAM AND 16.00Z GFS SHOWING ONLY SOME HIGH LEVEL CLOUDS WITH IT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...04
AREA FORECAST DISCUSSION
NWS MIAMI FL
1016 AM EDT SAT AUG 16 2014
.UPDATE...
DEEP LAYER RIDGE CONTINUES TO BE SUPPRESSED TO THE SOUTH AS A
LARGE SCALE MID LEVEL TROUGH REMAINS OVER THE NORTHEAST STATES.
THIS WILL MAINTAIN A SOUTHWEST TO WEST STEERING FLOW ACROSS SOUTH
FLORIDA AND THE 12Z MFL SOUNDING CONFIRMS THIS. THE ATMOSPHERIC
PROFILE ALSO LOOKS VERY SIMILAR TO YESTERDAY ALTHOUGH PWAT
ACTUALLY INCREASED BY JUST UNDER A QUARTER OF AN INCH TO NOW AN
EVEN TWO INCHES. MID LEVEL LAPSE RATES ALSO CONTINUE TO BE FAIRLY
IMPRESSIVE AT 6.2C/KM. ALL OF THIS SAID, THE INTERIOR AND EAST
COAST WILL BE THE MOST FAVORABLE FOR AFTERNOON THUNDERSTORMS WITH
POSSIBLE LOCALIZED URBAN STREET FLOODING ESPECIALLY ALONG THE EAST
COAST METRO AREAS AND WILL ADJUST THE POPS TO ACCOUNT FOR THIS.
THE HRRR IS ALSO SHOWING THIS PATTERN BUT FOR WHATEVER REASON THE
LATEST 11 AND 12Z RUNS HAVE BACKED OFF ON THE COVERAGE AND AM
HAVING A HARD TIME REASONING WITH A LESS CHANCE. THEREFORE, WILL
INCREASE THOSE CHANCES TO LIKELY FOR MOST OF THE INTERIOR AND EAST
COAST.
KOB
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1124 AM EDT SAT AUG 16 2014
.SYNOPSIS...
HIGH PRESSURE EXTENDING FROM THE ATLANTIC WESTWARD ALONG THE GULF
COAST WILL DOMINATE THROUGH MONDAY. THIS FEATURE WILL KEEP THE
FORECAST AREA MAINLY DRY WITH SEASONABLE TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
THIS AFTERNOON...THE LATEST ANALYSIS INDICATED A WEAK PRESSURE PATTERN.
MOISTURE WAS SHALLOW. DESPITE STRONG HEATING THE THUNDERSTORM
CHANCE IS LOW BECAUSE OF LIMITED MOISTURE AND THE LACK OF A WELL-
DEFINED SURFACE FEATURE. BELIEVE ANY THUNDERSTORMS WILL BE
ISOLATED AND MAINLY CONFINED TO A FEW LOCATIONS IN THE EAST
SECTION OF THE FORECAST AREA WHERE DEWPOINT TEMPERATURES WERE
HIGHER. THE 11Z HRRR CONFINED THUNDERSTORMS TO NEAR THE SEA-BREEZE
FRONT AND JUST EAST OF THE FORECAST AREA THROUGH 02Z.
TONIGHT...THE SURFACE RIDGE TO OUR SOUTH WILL CONTINUE TO DOMINATE.
ANY THUNDERSTORMS SHOULD DISSIPATE THIS EVENING WITH THE LOSS OF
HEATING. THE TEMPERATURE GUIDANCE WAS CONSISTENT. LINGERING LOW-
LEVEL MOISTURE UNDER THE NOCTURNAL INVERSION MAY SUPPORT FOG. THE
MODELS INDICATE DRYING SO THE FOG WILL LIKELY NOT BE AS EXTENSIVE
AS WHAT OCCURRED LAST NIGHT. EXPECT PATCHY FOG.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
A DRY FORECAST IS ON TAP THROUGH SUNDAY. FOR THE MOST PART SUNDAY
SHOULD BE A REPEAT OF SATURDAY...WITH MAINLY ISOLATED RAINFALL
ACROSS THE COASTAL PLAIN. OVERNIGHT LOWS TONIGHT WILL FALL TO
AROUND 70...WITH HIGHS ON SUNDAY IN THE LOWER TO MIDDLE 90S.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
NO CHANGES MADE IN THE LONG TERM. THE GFS AND ECMWF DISPLAY
RIDGING EXTENDING FROM THE ATLANTIC WESTWARD NEAR THE GULF COAST
THROUGH THE MEDIUM- RANGE PERIOD. FARTHER NORTH THE MODELS SHOW
LEE-SIDE TROUGHING IN THE FORECAST AREA DURING MUCH OF THE PERIOD.
A FRONT DROPPING SOUTHWARD MAY EXTEND THROUGH THE FORECAST AREA
DURING PART OF THE PERIOD. THE RIDGE TO THE SOUTH SHOULD LIMIT
MOISTURE. THE MODELS SHOW STRONGER CONVERGENCE AND DEEPER MOISTURE
NORTH OF THE FORECAST AREA. THE GFS...ECMWF...AND EKD MOS HAVE
POPS 20 TO 30 PERCENT. EXPECT HIGH TEMPERATURES ABOVE NORMAL WITH
THE RIDGE TO THE SOUTH DIRECTING A WESTERLY FLOW INTO THE FORECAST
AREA. THE GUIDANCE HAS HIGHS MAINLY IN THE MIDDLE 90S THROUGH THE
PERIOD.
&&
.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
EXPECT MAINLY VFR CONDITIONS CONTINUING THROUGH THIS EVENING. ANY
THUNDERSTORMS SHOULD BE ISOLATED BECAUSE OF SHALLOW MOISTURE. THE
CHANCE IS TOO LOW TO INCLUDE IN THE TERMINAL FORECASTS AT THIS
TIME. THE PRESSURE GRADIENT WILL BE WEAK AND THERE WILL BE
VARIABILITY IN THE WIND DIRECTION. NOCTURNAL COOLING AND LINGERING
LOW-LEVEL MOISTURE MAY SUPPORT STRATUS AND FOG AGAIN EARLY SUNDAY
MORNING. FORECASTED CONDITIONS MORE PESSIMISTIC THAN THE GFS AND
NAM MOS MAINLY BASED ON WHAT OCCURRED LAST NIGHT. THE MODELS MAY
BE TOO FAST WITH THE DRYING IN THIS WEAK FLOW PATTERN.
EXTENDED AVIATION OUTLOOK...MVFR OR IFR CONDITIONS POSSIBLE IN
LATE NIGHT AND EARLY MORNING FOG. SCATTERED AFTERNOON AND EVENING
THUNDERSTORMS ALSO MAY BRING RESTRICTIONS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1118 AM EDT SAT AUG 16 2014
.SYNOPSIS...
HIGH PRESSURE EXTENDING FROM THE ATLANTIC WESTWARD ALONG THE GULF
COAST WILL DOMINATE THROUGH MONDAY. THIS FEATURE WILL KEEP THE
FORECAST AREA MAINLY DRY WITH SEASONABLE TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
THIS AFTERNOON...THE LATEST ANALYSIS INDICATED A WEAK PRESSURE PATTERN.
MOISTURE WAS SHALLOW. DESPITE STRONG HEATING THE THUNDERSTORM
CHANCE IS LOW BECAUSE OF LIMITED MOISTURE AND THE LACK OF A WELL-
DEFINED SURFACE FEATURE. BELIEVE ANY THUNDERSTORMS WILL BE
ISOLATED AND MAINLY CONFINED TO A FEW LOCATIONS IN THE EAST
SECTION OF THE FORECAST AREA WHERE DEWPOINT TEMPERATURES WERE
HIGHER. THE 11Z HRRR CONFINED THUNDERSTORMS TO NEAR THE SEA-BREEZE
FRONT AND JUST EAST OF THE FORECAST AREA THROUGH 02Z.
TONIGHT...THE SURFACE RIDGE TO OUR SOUTH WILL CONTINUE TO DOMINATE.
ANY THUNDERSTORMS SHOULD DISSIPATE THIS EVENING WITH THE LOSS OF
HEATING. THE TEMPERATURE GUIDANCE WAS CONSISTENT. LINGERING LOW-
LEVEL MOISTURE UNDER THE NOCTURNAL INVERSION MAY SUPPORT FOG. THE
MODELS INDICATE DRYING SO THE FOG WILL LIKELY NOT BE AS EXTENSIVE
AS WHAT OCCURRED LAST NIGHT. EXPECT PATCHY FOG.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
A DRY FORECAST IS ON TAP THROUGH SUNDAY. FOR THE MOST PART SUNDAY
SHOULD BE A REPEAT OF SATURDAY...WITH MAINLY ISOLATED RAINFALL
ACROSS THE COASTAL PLAIN. OVERNIGHT LOWS TONIGHT WILL FALL TO
AROUND 70...WITH HIGHS ON SUNDAY IN THE LOWER TO MIDDLE 90S.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
NO CHANGES MADE IN THE LONG TERM. THE GFS AND ECMWF DISPLAY
RIDGING EXTENDING FROM THE ATLANTIC WESTWARD NEAR THE GULF COAST
THROUGH THE MEDIUM- RANGE PERIOD. FARTHER NORTH THE MODELS SHOW
LEE-SIDE TROUGHING IN THE FORECAST AREA DURING MUCH OF THE PERIOD.
A FRONT DROPPING SOUTHWARD MAY EXTEND THROUGH THE FORECAST AREA
DURING PART OF THE PERIOD. THE RIDGE TO THE SOUTH SHOULD LIMIT
MOISTURE. THE MODELS SHOW STRONGER CONVERGENCE AND DEEPER MOISTURE
NORTH OF THE FORECAST AREA. THE GFS...ECMWF...AND EKD MOS HAVE
POPS 20 TO 30 PERCENT. EXPECT HIGH TEMPERATURES ABOVE NORMAL WITH
THE RIDGE TO THE SOUTH DIRECTING A WESTERLY FLOW INTO THE FORECAST
AREA. THE GUIDANCE HAS HIGHS MAINLY IN THE MIDDLE 90S THROUGH THE
PERIOD.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
MUCH OF THE AREA HAD STRATUS AND FOG EARLY THIS MORNING. STRONG
HEATING SHOULD RESULT IN IMPROVING CONDITIONS LATER THIS MORNING.
USED THE GFS LAMP AND CONDITIONAL CLIMATOLOGY FOR THE TIMING OF
IMPROVEMENT LATER THIS MORNING. EXPECT MAINLY VFR CONDITIONS
CONTINUING THIS AFTERNOON AND EVENING. ANY THUNDERSTORMS SHOULD BE
ISOLATED BECAUSE OF SHALLOW MOISTURE. THE CHANCE IS TOO LOW TO
INCLUDE IN THE TERMINAL FORECASTS AT THIS TIME. THE PRESSURE
GRADIENT WILL BE WEAK TODAY AND THERE WILL BE VARIABILITY IN THE
WIND DIRECTION. NOCTURNAL COOLING AND LINGERING LOW-LEVEL
MOISTURE MAY SUPPORT STRATUS AND FOG AGAIN EARLY SUNDAY MORNING.
FORECASTED CONDITIONS MORE PESSIMISTIC THAN THE GFS AND NAM MOS
MAINLY BASED ON WHAT OCCURRED LAST NIGHT. THE MODELS MAY BE TOO
FAST WITH THE DRYING IN THIS WEAK FLOW PATTERN.
EXTENDED AVIATION OUTLOOK...MVFR OR IFR CONDITIONS POSSIBLE IN
LATE NIGHT AND EARLY MORNING FOG. SCATTERED AFTERNOON AND EVENING
THUNDERSTORMS ALSO MAY BRING RESTRICTIONS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
617 AM EDT SAT AUG 16 2014
.SYNOPSIS...
HIGH PRESSURE EXTENDING FROM THE ATLANTIC WESTWARD ALONG THE GULF
COAST WILL DOMINATE DURING THE WEEKEND. THIS FEATURE WILL KEEP THE
FORECAST AREA MAINLY DRY WITH SEASONABLE TEMPERATURES.
&&
.NEAR TERM /TODAY/...
AFTER STARTING THE DAY WITH SOME STRATUS/FOG...SKIES WILL BECOME
PARTLY CLOUDY ONCE AGAIN. MODELS CONTINUE WITH WEAK SURFACE HIGH
ACROSS THE CWA...WITH WEAK TROUGHING ALONG THE COAST AND ALONG THE
REMNANTS OF AN OLD FRONTAL BOUNDARY SOUTH OF THE AREA. CAN NOT
RULE OUT AN ISOLATED SHOWER OR STORM IN A FEW AREAS LATE IN THE
AFTERNOON...BUT CONFIDENCE IS NOT HIGH ENOUGH TO WARRANT PLACING
IN THE FORECAST AT THIS TIME. BEST CHANCE WILL PROBABLY REMAIN
EAST OF THE CWA CLOSER TO THE COAST. AFTERNOON HIGHS WILL CLIMB
INTO THE LOWER 90S.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
ANY ISOLATED RAINFALL WILL DISSIPATE QUICKLY AFTER SUNSET...WITH
A DRY FORECAST ON TAP TONIGHT THROUGH SUNDAY. FOR THE MOST PART
SUNDAY SHOULD BE A REPEAT OF SATURDAY...WITH MAINLY ISOLATED
RAINFALL ACROSS THE COASTAL PLAIN. OVERNIGHT LOWS TONIGHT WILL
FALL TO AROUND 70...WITH HIGHS ON SUNDAY IN THE LOWER TO MIDDLE
90S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
NO CHANGES MADE IN THE LONG TERM. THE GFS AND ECMWF DISPLAY
RIDGING EXTENDING FROM THE ATLANTIC WESTWARD NEAR THE GULF COAST
THROUGH THE MEDIUM- RANGE PERIOD. FARTHER NORTH THE MODELS SHOW
LEE-SIDE TROUGHING IN THE FORECAST AREA DURING MUCH OF THE PERIOD.
A FRONT DROPPING SOUTHWARD MAY EXTEND THROUGH THE FORECAST AREA
DURING PART OF THE PERIOD. THE RIDGE TO THE SOUTH SHOULD LIMIT
MOISTURE. THE MODELS SHOW STRONGER CONVERGENCE AND DEEPER MOISTURE
NORTH OF THE FORECAST AREA. THE GFS...ECMWF...AND EKD MOS HAVE
POPS 20 TO 30 PERCENT. EXPECT HIGH TEMPERATURES ABOVE NORMAL WITH
THE RIDGE TO THE SOUTH DIRECTING A WESTERLY FLOW INTO THE FORECAST
AREA. THE GUIDANCE HAS HIGHS MAINLY IN THE MIDDLE 90S THROUGH THE
PERIOD.
&&
.AVIATION /10Z SATURDAY THROUGH WEDNESDAY/...
PERIODS OF MVFR/IFR CEILINGS EARLY THIS MORNING...THEN BECOMING VFR
CONDITIONS THROUGH THE REMAINDER OF THE DAY.
DEWPOINT TEMPERATURES ARE QUITE A BIT HIGHER THAN LAST NIGHT WITH
VALUES IN THE LOWER 70S. THIS WILL LEAD TO STRATUS/FOG FORMATION
IN MOST AREAS. HRRR MODEL SHOWS A MORE AGGRESSIVE FOG SCENARIO
THAN SOME OF THE OTHER MODELS. HAVE INCLUDED MVFR/IFR GROUP AT FOG
PRONE AGS/OGB...WITH SIMILAR CONDITIONS POSSIBLE AT OTHER TAF
SITES. STRATUS/FOG SHOULD BREAK UP BETWEEN 13Z AND 14Z. WINDS
WILL PICK UP DURING THE DAY FROM THE SOUTHWEST AT 5 TO 7 KNOTS OR
LESS.
EXTENDED AVIATION OUTLOOK...MVFR CONDITIONS POSSIBLE IN LATE
NIGHT/EARLY MORNING FOG EACH NIGHT. SCATTERED AFTERNOON/EVENING
SHOWERS AND THUNDERSTORMS POSSIBLE MONDAY AND TUESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
947 AM CDT Sat Aug 16 2014
.UPDATE...
ISSUED AT 946 AM CDT SAT AUG 16 2014
Incoming area of showers and scattered storms has been showing
some fading over the last couple hours as it crosses the Illinois
River. Latest HRRR shows a narrower band of showers pushing past
the I-55 corridor midday, with some additional development
occurring to our west this afternoon near a low in southeast Iowa.
East central and southeast Illinois will see more in the way of
scattered showers through the day. Have sent some grid updates
earlier to reflect the current trends. Temperatures currently on
track and should mainly be confined to the 70s today with the
widespread cloud cover.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 323 AM CDT SAT AUG 16 2014
MCS over southern Iowa into northern Missouri early this morning
tracking slowly to the east and this feature will be our main
concern through tonight. Well out ahead of the MCS to our west, we
have had some isolated showers develop over parts of central and
east central Illinois during the past several hours. Unlike last
night at this time when we were seeing dew points in the upper 40s
to lower 50s over our northeast counties, most areas have seen the
dew points climb back well into the 60s.
Most of the short term models move the MCV associated with the
current convection out in northern Missouri/southern Iowa slowly
into southeast Iowa by late this afternoon. Current band of showers
and isolated storms will shift slowly east of the Mississippi River
by dawn this morning and continue to edge slowly east during the
morning with a gradual decrease in areal coverage as the main
support from the low level jet wanes with time early this morning.
The extensive cloud cover and showers will keep temps below guid in
most areas except the far east where the rain will not get into that
part of our forecast area until later today.
Most of the hi-resolution model solutions redevelop the convection
to the east of the MCV later this afternoon into parts of west
central Illinois and then shift the precip to the east tonight as
the vort center tracks into central IL by Sunday morning.
Precipitable water values still forecast well above 2 inches tonight
with warm cloud depths above 3km indicating some very efficient
rains with any convection that develops just to the east of the vort
center tonight. Upper winds are also forecast to weaken considerably
indicating the storms that do develop near or to the east/southeast
of the MCV will be slow movers and threaten parts of our area with
heavy rainfall. However, one negative factor for widespread heavy
rainfall will be with a much weaker low level jet than what we are
seeing out to our west tonight. Still, with the high PWAT values in
place, any storms that develop late this afternoon thru this evening
will be capable of producing high rainfall rates along and to the
east of the MCV overnight.
&&
.LONG TERM...(Sunday through Friday)
ISSUED AT 323 AM CDT SAT AUG 16 2014
Upper disturbance remaining over the FA Sunday morning in the
models. Models not really responding to the MCV equally as the low
moves out to the east. A lot of uncertainty as the day progresses,
but the better chances for the continuation of precip remain in the
east and southeast as the system tracks out to the east, just north
of the Ohio River Valley. Models dry out briefly for early Monday
morning, and chances through the day on Monday starting to drop off
a bit. Less amplified flow over the country looking messy through
the work week. Heat that has been building over the desert
southwest makes its way into the region warming up the temps to far
more of a summer pattern that has been to this point. Temps in the
upper 80s/lower 90s Wed-Friday. Weak flow aloft and a series of
small waves dipping into the Great Lakes/Midwest keeping ILX in an
unsettled weather pattern and pops dominate the extended forecast
with periodic chances for precip. Models diverge significantly
going into the weekend with the GFS building in a ridge for the
Midwest and southern Plains, while the ECMWF remains more
progressive with pushing a trof across the nrn tier of the CONUS.
Should the forecast go more the way of the GFS with subsequent
issues, the temperatures may need to be bumped up a couple degrees
under a persistent ridge. But with the ECMWF in direct opposition
and the timing of waves such a question mark...not willing to
deviate too much from what the AllBlend has in the grids just yet.
All in all, a warm forecast with periodic showers. PW values
trending down from where they were 24 hrs ago, but chances for some
of the thunderstorms to produce some heavy rain. Upper dynamics not
particularly alarming any one day just yet...but this pattern is
more reminiscent of summer than what has been around so far.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
ISSUED AT 600 AM CDT SAT AUG 16 2014
As a large area of showers and isolated thunderstorms pushes into
western Illinois this morning, we expect a gradual deterioration
in cigs and vsbys from west to east today. Rain will continue to
edge slowly east and start to affect the SPI taf area first this
morning followed by PIA with the remainder of the TAF sites seeing
the rain late this morning into the afternoon. Already seeing some
isolated showers just east of CMI, but still think the bulk of the
rain to the west may take until this afternoon to get into CMI.
Once the rain begins, cigs will drop to MVFR and even the possibility
for some brief IFR cigs/vsbys in the heavier showers. Not seeing much
in the way of lightning activity so at this point will continue to
handle it with SHRA with VCTS. As the upper level circulation works
its way into our area tonight, it appears we will see widespread
MVFR and local IFR cigs and vsbys with rain and isolated TSRA with
areas of fog. Surface winds today will be south to southeast at 8
to 15 kts with winds backing more into the east tonight as the
surface low tracks just south of the TAF sites. Wind speeds tonight
will be from 4 to 9 kts.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEELHART
SHORT TERM...SMITH
LONG TERM...HJS
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
755 AM EDT SAT AUG 16 2014
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 323 AM EDT SAT AUG 16 2014
SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE TODAY WITH THE
GREATEST LIKELIHOOD ACROSS CENTRAL LOWER MI THIS AFTERNOON WITH LESS
COVERAGE ANTICIPATED ACROSS SOUTHERN LOWER MI THIS EVENING AND
TONIGHT. MOST OF SUNDAY AND MONDAY WILL BE DRY ALTHOUGH A FEW
SHOWERS MAY POP UP BOTH DAYS MAINLY SOUTH OF A GRAND RAPIDS TO
LANSING LINE. TUESDAY THROUGH FRIDAY LOOKS WARM AND UNSETTLED AT
TIMES WITH OPPORTUNITIES FOR MORE SHOWERS AND STORMS.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 323 AM EDT SAT AUG 16 2014
NOT MUCH HAS CHANGED WITH PREVIOUS THINKING REGARDING CONVECTIVE
EVOLUTION TODAY THROUGH SUNDAY. THE MAIN THEME WILL BE MORE NUMEROUS
SHOWERS AND THUNDERSTORMS ACROSS CENTRAL LOWER MI DURING THE
AFTERNOON HOURS WITH A MORE NARROW LINE OF SCATTERED SHOWERS/STORMS
MOVING THROUGH SOUTHERN LOWER FOR THE EVENING AND LATE NIGHT HOURS.
THE SEVERE WEATHER THREAT LOOKS QUITE LOW OVERALL.
HI RES MODELS INCLUDING THE NSSL WRF AND HRRR INDICATE THE BROKEN
LINE OF SHOWERS/STORMS CURRENTLY OVER NORTHERN WI / U.P. AREA WILL
MOVE SOUTHEAST AND BE MOST WIDESPREAD ACROSS NORTHERN AND CENTRAL
LOWER MI THIS AFTERNOON WHERE H500 HEIGHTS ARE LOWEST AND SFC CONV
AS WELL AS LOW LEVEL MOISTURE FLUX CONV WILL BE MAXIMIZED. HI RES
RADAR REF SIM SUGGESTS THE CONVECTIVE EVOLUTION WILL BE A
NARROW...HORIZONTALLY DRAPED LINE OF SCATTERED SHOWERS AND A FEW
STORMS THAT MOVES FROM ROUTE 10 TO I-96 BETWEEN 18Z AND 00Z...THEN
FROM I-96 TO I-94 FROM 00Z TO 06Z.
NAM BUFKIT SOUNDINGS HAVE TRENDED VERY MUCH TOWARD GFS SOUNDINGS IN
KEEPING INSTABILITY QUITE LOW FOR ALMOST THE ENTIRE CWA...EXCEPT FOR
OUR FAR NE PORTION INCLUDING MT PLEASANT AND CLARE. THIS REGION HAS
THE BEST OPPORTUNITY FOR THUNDERSTORMS DURING THE AFTERNOON HOURS.
HOWEVER...MID LEVEL LAPSE RATES CONTINUE TO MITIGATE ANY SUBSTANTIAL
HAIL THREAT AND SFC BASED CAPE MAY ONLY BE A FEW HUNDRED J/KG...SO
EQUILIBRIUM LEVELS MAY NOT BE VERY IMPRESSIVE AND A SEVERE WEATHER
THREAT LOOKS TO BE HELD DOWN CONSIDERABLY. SO...WE`LL CONTINUE TO
WATCH FOR SOME GUSTY WINDS IN THE STRONGER STORMS BUT OVERALL THIS
EVENT LOOKS MARGINAL.
SUNDAY LOOKS DRY FOR MOST AREAS SAVE NEAR AND SOUTH OF I-94 WERE
A FEW SHOWERS MAY DEVELOP IN THE MIDST OF A H850 THERMAL AND
MOISTURE GRADIENT AND WEAK EASTERLY SFC CONV. EVEN INTO
MONDAY...WITH THE H850 THERMAL GRADIENT STILL IN PLACE AND A WEAK
H500 SHORTWAVE MOVING THROUGH DURING PEAK HEATING...SOME ISOLATED
SHOWERS MAY DEVELOP. THIS WOULD PRIMARILY BE FOR AREAS SOUTH OF A
GRR TO LAN LINE. NONE OF THIS ACTIVITY ON SUNDAY OR MONDAY LOOKS
WIDESPREAD OR SIGNIFICANT. HAVE REMOVED ALL MENTION OF THUNDER FOR
BOTH OF THESE DAYS AS MODEL SOUNDINGS DO NOT SUPPORT IT.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 323 AM EDT SAT AUG 16 2014
HIGH CONFIDENCE IN WARM SUMMERLIKE TEMPERATURES IN THE LONG TERM
PERIOD... ALTHOUGH IT LOOKS LIKE THE HOT/HUMID/UNCOMFORTABLE AIR
WITH HIGHS AROUND 90 AND DEW POINTS NEAR 70 SHOULD REMAIN JUST TO
OUR SOUTHWEST.
EARLY NEXT WEEK WE WILL BE WATCHING A SLOW MOVING SHORTWAVE WHICH
MOVES FROM NORTHERN MINNESOTA ON MONDAY TO WISCONSIN ON TUESDAY TO
LWR MI ON WEDNESDAY. A WEAK/ILL DEFINED SFC TROUGH/WARM FRONT...
ORIENTED IN A NW-SE FASHION... ACCOMPANIES/PRECEDES THIS FEATURE AS
IT IMPACTS THE UPR MIDWEST AND GRTLKS REGION DURING THE EARLY TO MID
WEEK PERIOD.
OUR BEST CHANCE OF SHOWERS/TSTMS WOULD APPEAR TO BE ON TUESDAY AND
WEDNESDAY... PARTICULARLY IN THE AFTERNOON/EVENING HOURS WITH
DIURNAL BOOST.
ONCE THE SHORTWAVE EXITS THE REGION BY THURSDAY... HEIGHT RISES
COMMENCE. HOWEVER A CHANCE OF A FEW SHOWERS AND TSTMS WILL REMAIN
SINCE THE WARM FRONT SHOULD BE SITUATED JUST TO OUR SOUTHWEST.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 755 AM EDT SAT AUG 16 2014
VFR CONDITIONS ARE EXPECTED TODAY INTO THIS EVENING. THE CHANCE OF
SHOWERS AND ISOLATED THUNDERSTORMS IS NOT EXPECTED TO REACH THE
TAF SITES ALONG THE I-96 CORRIDOR UNTIL AFTER 22Z... AND A COUPLE
HOURS LATER ALONG THE I-94 CORRIDOR. EVEN WITH THE SCATTERED
SHOWERS IT SHOULD REMAIN PRIMARILY VFR.
WHILE THERE IS A THUNDER THREAT LATE TODAY AND THIS EVENING... FEEL
THE PROBABILITY IS TOO LOW TO INCLUDE VCTS IN ANY OF THE TAFS AT
THIS TIME... WITH THE EXCEPTION OF LAN.
WEST-SOUTHWEST SFC WINDS OF 10 TO 20 KTS WITH SOME HIGHER GUSTS
WILL OCCUR MUCH OF TODAY... THEN DIMINISH QUICKLY AFTER 22Z AS THE
SFC COLD FRONT APPROACHES FROM THE NORTH AND THE GRADIENT RELAXES.
AFTER 06Z TONIGHT SOME LOWER CIGS/VSBYS WILL PROBABLY DEVELOP
BEHIND THE COLD FRONT. IFR CONDITIONS ARE QUITE POSSIBLE BY 12Z
SUNDAY MORNING...ESPECIALLY SOUTH AND EAST OF GRR.
&&
.MARINE...
ISSUED AT 323 AM EDT SAT AUG 16 2014
A 2 TO 3 FOOT CHOP CAN BE EXPECTED THIS MORNING AND AFTERNOON WITH
SW WINDS PICKING UP. WINDS AND WAVES DECREASE THIS EVENING AND
EASTERLY WINDS WILL KEEP MOST WAVE ACTION AWAY FROM OUR NEARSHORE
ZONES ON MONDAY.
&&
.HYDROLOGY...
ISSUED AT 323 AM EDT SAT AUG 16 2014
NO SIGNIFICANT RAINFALL IS EXPECTED OVER THE NEXT FEW DAYS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...HOVING
SHORT TERM...HOVING
LONG TERM...MEADE
AVIATION...MEADE
HYDROLOGY...HOVING
MARINE...HOVING
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1031 AM EDT SAT AUG 16 2014
.SYNOPSIS...
INCREASING HEAT AND HUMIDITY WILL DEVELOP THROUGH THE WEEKEND AND
INTO EARLY NEXT WEEK AS A TYPICAL SUMMERTIME PATTERN DEVELOPS. A
WEAK COLD FRONT WILL APPROACH TUESDAY NIGHT BEFORE DISSIPATING
ACROSS THE AREA EARLY WEDNESDAY. HOT TEMPERATURES WITH HIGH
HUMIDITY ARE EXPECTED FOR THE MIDDLE AND LATTER PART OF THE
UPCOMING WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM SATURDAY...THE MAIN FORECAST CHALLENGE CONTINUES TO
BE POPS. THE LATEST NAM IS VERY SPARSE ON THE COVERAGE WITH WHAT
LITTLE IT DEVELOPS LATER AROUND 0300 UTC. THIS APPEARS TO BE
ASSOCIATED WITH A SUBTLE SHORTWAVE. THE RAP CONTINUES TO SHOW MORE
COVERAGE FROM NOW THROUGH THE AFTERNOON HOURS. BASED ON THIS AND
THE FACT THERE ARE A FEW LIGHT SHOWERS POPPING UP IN HORRY
COUNTY...WILL CONTINUE TO ADVERTISE SLIGHT CHANCE POPS FOR THE
REMAINDER OF THE DAY. TEMPERATURE TRENDS LOOK GOOD.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SATURDAY...LONGWAVE TROUGH CENTERED OVER THE CANADIAN
MARITIMES WILL FLATTEN SUNDAY...WITH BRIEF SHORTWAVE RIDGING LIKELY
MOVING OVERHEAD DURING THE EVENING. THIS CREATES WESTERLY MID-LEVEL
FLOW WHICH DRIES THE MIDDLE PORTIONS OF THE COLUMN...WHILE AT THE
SAME TIME HELPS TO WARM TEMPS TO ABOVE NORMAL AT THE SURFACE. BROAD
RETURN FLOW AROUND AN EXPANDING AREA OF HIGH PRESSURE OFFSHORE WILL
PUMP WARM/MOIST AIR INTO THE REGION IN THE LOWER PORTIONS OF THE
COLUMN...CAUSING INCREASED INSTABILITY TO SURFACE PARCELS SUNDAY.
HOWEVER...THE WARMING TEMPS IN THE 850-500MB LAYER COMBINED WITH THE
DRYING FLOW WILL INHIBIT WIDESPREAD CONVECTION. THUS...EVEN AS TEMPS
SOAR INTO THE LOW 90S...CONVECTION WILL BE LIMITED TO THE SEA-BREEZE
BOUNDARY...AND POP IS MAINTAINED ONLY IN THE SCHC RANGE. ANY STORMS
SUNDAY WILL WANE QUICKLY AFTER DARK...AND A WARM NIGHT IS EXPECTED
WITH LOWS ONLY FALLING INTO THE MID 70S AT THE COAST...LOW 70S
INLAND.
THE FOCUS ON MONDAY REVOLVES AROUND A FAIRLY POTENT...BUT
WEAKENING...500MB LOW TRAVERSING JUST NORTH OF THE AREA. AHEAD OF
THIS FEATURE...CONTINUED SHORTWAVE RIDGING COMBINED WITH SW SURFACE
FLOW WILL DRIVE TEMPS AGAIN TO AROUND 95 AWAY FROM THE COAST...AND
AROUND 90 AT THE BEACHES. THE SURFACE REFLECTION OF THIS FEATURE IS
EXPECTED TO REMAIN NORTH OF THE NC/VA BORDER AS IT RACES EAST TO BE
OFFSHORE BY TUESDAY...THUS NO DIRECT IMPACTS ARE EXPECTED LOCALLY.
HOWEVER...INCREASING MOISTURE AS WELL AS SLOWLY THINNING 1000-500MB
THICKNESSES ASSOCIATED WITH THIS IMPULSE WILL CREATE HIGHER POP
CHANCES MONDAY...WITH SCATTERED CONVECTION EXPECTED.
ADDITIONALLY...SHOWERS/STORMS MAY PERSIST TEMPORALLY BEYOND TYPICAL
DIURNAL ACTIVITY AS COLUMN MOISTURE INCREASES THROUGH THE NIGHT
THANKS TO THE CLOSEST APPROACH OF THE MID-LEVEL AND SURFACE
FEATURES. MINS MONDAY NIGHT WILL BE VERY WARM...WITH UPPER 70S
EXPECTED AT THE COAST AND MID 70S WELL INLAND.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 300 AM SATURDAY...WEAK COLD FRONT WILL APPROACH ON
TUESDAY...POSSIBLY CROSSING THE AREA BEFORE WASHING OUT BY EARLY
WEDNESDAY. THEREAFTER...A PERIOD OF HOT AND HUMID WEATHER IS
EXPECTED FOR THE REMAINDER OF NEXT WEEK.
MID-LEVEL IMPULSE AND ASSOCIATED SURFACE LOW WILL BE MOVING OFF THE
VIRGINIA COAST AT THE START OF THE PERIOD. A WEAK COLD FRONT
TRAILING THE SURFACE FEATURE WILL TRY TO DROP SOUTH INTO THE AREA
LATE TUESDAY NIGHT...BUT IT WILL BECOME ORIENTED PARALLEL TO THE
MID-LEVEL FLOW AND LIKELY STALL JUST NORTH OF THE CWA...ALTHOUGH A
BRIEF WIND SHIFT TO THE NORTH IS POSSIBLE VERY LATE TUESDAY
NIGHT...ESPECIALLY ACROSS NC COUNTIES. LITTLE OTHER IMPACTS ARE
ANTICIPATED...AND TUESDAY WILL FEATURE SLIGHTLY ABOVE NORMAL TEMPS
WITH DIURNAL TSTM CHANCES.
BY WEDNESDAY...AND THEN THROUGH THE REST OF THE PERIOD...EXPANSIVE
UPPER RIDGE BEGINS TO BUILD BACK TO THE WEST AND BLOSSOM ACROSS THE
SOUTHEAST. THE SURFACE HIGH OVER THE WESTERN ATLANTIC IS FORCED TO
RE-ORGANIZE TO THE WEST AS WELL...STRENGTHENING ALONG THE SOUTHERN
TIER...WHICH SUGGESTS A PERIOD OF WELL-ABOVE NORMAL TEMPS FOR LATE
IN THE WEEK. THE ECM AND GFS DISAGREE ON EXACTLY WHERE THE RIDGE
AXIS WILL SETUP...WITH THE ECM KEEPING IT NEARLY OVERHEAD THIS
AREA...WHILE THE GFS DEPICTS IT ACROSS THE MS VLY. WHILE THIS WILL
HAVE LITTLE IMPACT ON TEMPS...WHICH SHOULD BE AROUND 5 DEGREES ABOVE
NORMAL (ALTHOUGH ECM WOULD BE A BIT WARMER)...PRECIP CHANCES WILL BE
DECREASED IN THE ECM SOLUTION VERSUS THE GFS. WILL LEAN ON THE
WARMER/DRIER ECM WHICH IS FAVORED BY WPC AND HAS BEEN MORE
CONSISTENT. STILL WILL EXPECT TO SEE AT LEAST ISOLATED DIURNAL
CONVECTION EACH DAY...AS A TYPICAL SUMMERTIME PATTERN FINALLY
RETURNS TO THE AREA. ADDITIONALLY...WITH THE HIGH TEMPS AND HIGH
DEWPOINTS...EXPECT HEAT INDICES TO REACH OR EXCEED 100 ACROSS THE
AREA ALL OF NEXT WEEK.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
AS OF 12Z...AREAS OF MVFR DUE TO FOG EARLY THIS MORNING AND AGAIN
TOWARDS THE END OF THE VALID PERIOD. OTHERWISE EXPECT VFR WITH
ISOLATED TO SCATTERED SHRA/TSRA POSSIBLE THIS AFTERNOON.
NEARLY CLEAR SKIES AND LIGHT WINDS PREVAIL ACROSS THE AREA THIS
MORNING...WITH SOME TAF SITES OBSERVING MVFR FOG. EXPECT FOG TO
DISSIPATE OVER THE NEXT FEW HOURS GIVING WAY TO VFR. INTO THE
AFTERNOON HOURS WILL SEE INCREASING SOUTHERLY WINDS AROUND 10 KTS OR
LESS AND FEW/SCT CLOUDS AROUND 4-5KFT. GIVEN ATMOSPHERIC CONDITIONS
AND LATEST FCST SOUNDINGS...COULD NOT RULE OUT ISOLATED TO SCATTERED
SHRA/TSRA...ESPECIALLY ALONG THE AFTERNOON SEABREEZE. THIS
EVENING...ANY CONVECTION WILL TAPER OFF AND VFR WILL PREVAIL WITH
CLEARING SKIES AND WINDS BECOMING LIGHT. GIVEN IDEAL RADIATIONAL
COOLING CONDITIONS...ANTICIPATE MVFR FOG...ESPECIALLY
INLAND...TOWARDS THE END OF THE VALID TAF PERIOD.
EXTENDED OUTLOOK...INCREASING CHANCES FOR ISOLATED TO SCATTERED AFTN
SHOWERS/TSTMS MONDAY THROUGH WEDNESDAY. OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM SATURDAY...WINDS AND SEAS LOOK GOOD WITH THE MORNING
UPDATE. JMPN7 IS REPORTING WIND SPEEDS IN THE SINGLE DIGITS AND
41110 SHOWING 1.3 FEET. BENIGN CONDITIONS WILL CONTINUE THROUGH THE
AFTERNOON HOURS. NO CHANGES TO THE FORECAST.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SATURDAY...HIGH PRESSURE EXPANDING OFFSHORE WILL BE THE
PRIMARY FEATURE TO THE MARINE CONDITIONS DURING THE SHORT
TERM...PRODUCING SW WINDS THROUGH THE PERIOD. INITIALLY...THESE
WINDS WILL BE OF MODERATE STRENGTH...AROUND 10 KTS...BUT WILL
GRADUALLY INCREASE...AND BECOME 15-20 KTS MONDAY AHEAD OF AN
APPROACHING COLD FRONT. SEAS WILL BUILD IN RESPONSE TO THE
STRENGTHENING WINDS...RISING FROM 2-3 FT MUCH OF SUNDAY...TO 3-5 FT
MONDAY NIGHT.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 300 AM SATURDAY...HIGH PRESSURE OFFSHORE AND A WEAK COLD FRONT
APPROACHING FROM THE NORTH WILL PINCH THE PRESSURE GRADIENT
TUESDAY...DRIVING SW WINDS TO 15-20 KTS MUCH OF THE DAY. THERE IS
STILL SOME UNCERTAINTY INTO HOW FAR SOUTH THIS FRONT WILL REACH
BEFORE WASHING OUT...BUT EXPECT A BRIEF PERIOD OF NORTHERLY WINDS
ACROSS THE NC WATERS VERY EARLY WEDNESDAY...BEFORE SW WINDS RETURN
THROUGH THE END OF THE PERIOD...BUT AT SPEEDS OF ONLY AROUND 10 KTS.
SEAS WILL BE DRIVEN PRIMARILY BY A WIND-WAVE TUESDAY...REACHING 3-5
FT TUESDAY...BEFORE FALLING WEDNESDAY TO 2-3 FT ON THE EASING WINDS.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JDW
NEAR TERM...SHK
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
945 AM EDT SAT AUG 16 2014
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND OVER THE AREA FROM OFFSHORE THROUGH
EARLY NEXT WEEK WITH A TROUGH OF LOW PRESSURE INLAND. A WEAK COLD
FRONT WILL MOVE IN FROM THE NORTH TUESDAY NIGHT...THEN RETURN
NORTH WEDNESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 945 AM SATURDAY...WITH THE SHORTWAVE EXITING TO THE
NE...HAVE AN ISOLATED SHOWER THREAT ACROSS THE NORTH THROUGH THE
NEXT COUPLE HOURS. HIGH CLOUDS ARE ERODING WITH PLENTY OF HEATING.
ADJUSTED HOURLY TEMPS SLIGHTLY AS THEY CLIMB INTO THE 80S.
OTHERWISE...FORECAST IS ON TRACK FOR A TYPICAL SUMMER-LIKE DAY
WITH INLAND CONVECTION POSSIBLE IN THE AFTERNOON..
/PREVIOUS DISCUSSION/
AS OF 400 AM SATURDAY...ISOLATED SHOWER/TSTM THREAT WILL CONTINUE
ACROSS NRN HALF OF AREA THROUGH 8 AM AS ADDITIONAL ACTIVITY
DEVELOPING SOUTH OF MAIN AREA NEAR NC/VA LINE. HRRR HAS GOOD
HANDLE ON THIS ACTIVITY. ISOLATED THREAT PSBL OVER NE SECTIONS 8
AM TIL NOON AND CONTINUED PREVIOUS FCST 20 POP THERE. SHRT WV
ENERGY...HEATING...INLAND TROF AND SEA BREEZE SUPPORT ISOLATED
SHOWERS/TSTMS INLAND OF COAST THIS AFTN. HIGH TEMPS AROUND 90
INLAND WITH MID 80S OBX.
&&
.SHORT TERM /TONIGHT/...
AS OF 400 AM SATURDAY...ISOALATED CONVECTIVE THREAT WILL CONTINUE
INLAND THIS EVENING...WITH ANOTHER SHRT WV MOVING IN FROM W-NW.
MODELS SUPPORT ACTIVITY DIMINISHING OVERNIGHT...BUT SOME
REDEVELOPMENT PSBL ALONG COAST NEAR MORNING...THUS NO CHANGE TO
PREVIOUS FCST. MIN TEMPS FROM AROUND 70 INLAND TO MID 70S COAST.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
AS OF 330 AM SAT...LONG TERM PERIOD WILL BE DOMINATED BY WARMING
TEMPERATURE PATTERN WITH OCCASIONAL BOUTS OF SHOWERS AND
THUNDERSTORMS.
LOW LEVEL SFC FLOW RETURNS TO THE AREA THIS WEEKEND WITH INCREASING
TEMPS...THOUGH DEWPOINTS WILL BE A BIT SLOWER TO RESPOND SO STILL
EXPECTING NEAR CLIMO LOWS OVERNIGHT. CONTINUED TYPICAL SUMMERY
PATTERN ON SUNDAY WITH ISOLATED AFTERNOON THUNDERSHOWERS ALONG SEA
BREEZE FRONT.
MED/LONG RANGE MODELS IN FAIRLY GOOD AGREEMENT WITH RESPECT TO
SYNOPTIC REGIME THROUGH THE LONG TERM...WITH SLOWLY BUILDING HEIGHTS
AS MID ATLANTIC RIDGE BUILDS INTO THE DEEP SOUTH. THIS WILL BRING
HOT TEMPS AND HIGH HUMIDITY VALS AS LAYER MIX RATIOS INC TO AROUND
16 G/KG EARLY TO MID NEXT WEEK. THE REGION LOOKS TO REMAIN JUST
SOUTH OF THE STORM TRACK...THOUGH COULD BE AFFECTED BY A SYSTEM
EXPECTED TO TRAVERSE THE MID ATLANTIC REGION IN THE MON NIGHT TO TUE
TIME FRAME AND THEN AGAIN MID TO LATE WEEK.
FOR MONDAY AFTERNOON AND EVENING...HAVE AN INCREASING POP TREND AS
MODEL SUITE IS IN GOOD AGREEMENT ON A COMPACT SHORTWAVE TRAVERSING
THE MID ATLANTIC STATES...WITH SFC REFLECTION NOTED ACROSS THE
DELMARVA PENINSULA MON NIGHT. TRICKY TO PIN DOWN WHERE/WHEN
DEVELOPMENT WILL TAKE PLACE IN THIS CONVECTIVE REGIME...SO HAVE
CAPPED POPS IN THE CHANCE RANGE...LOWEST ACROSS THE SOUTHERN FA.
POTENTIAL MCS ACTIVITY COULD BRING A GOOD AMOUNT OF QPF TO PARTS OF
E NC THROUGH MON NIGHT. IN ADDITION...LAYER MIX RATIOS INC QUITE A
BIT INTO THE 17 G/KG RANGE WITH PWATS AROUND 2 INCHES. THE LOW MOVES
OFFSHORE ON TUE WITH ATTENDANT TRAILING COLD FRONT PUSHING INTO THE
AREA. KEPT CHANCE POPS TUE AS ANOTHER ROUND OF SHOWERS/STORMS COULD
AFFECT THE AREA AHEAD OF THE FRONT.
WED WILL MOST LIKELY BE A DRY DAY AS SUBSIDENCE TAKES PLACE BEHIND
EXITING LOW/SHORTWAVE BUT HAVE KEPT SLIGHT CHANCE POPS IN FCST AS
THERE IS STILL INSTABILITY PRESENT DUE TO A WARM AND MUGGY AIRMASS
IN PLACE.
THUR INTO NEXT WEEKEND...RIDGE BUILDS ACROSS THE CENTRAL CONUS
ALLOWING FOR UPR FLOW TO BECOME MORE NW ACROSS THE EASTERN SEABOARD.
THIS WILL BRING BOUTS OF NW FLOW CONVECTION WITH H85 MB BAROCLINIC
ZONE LOCATED IN THE VCNTY. HAVE PAINTED LOW CHANCE POPS FOR THIS
PERIOD AS OCNL SHORTWAVE ACTIVITY WILL AFFECT THE AREA.
TEMPS DURING THE PERIOD WILL BE QUITE WARM AND ABOVE CLIMO...WITH
THICKNESSES SUGGESTING HIGHS IN THE LOW TO OCNL MID 90S PERHAPS AT
TIMES. LOWS WILL BE MUGGY IN THE 70S.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM /THROUGH 12Z SUNDAY/...
AS OF 720 AM SATURDAY...VFR EXPECTED THROUGH THIS EVENING...THEN
PERIOD OF MVFR VSBYS LIKELY LATE TONIGHT MOST SITES. ISOLATED
CONVECTIVE ACTIVITY PSBL WITH SEA BREEZE AND INLAND TROFFING BUT
COVERAGE TOO LIMITED TO MENTION IN TAFS. LATEST GDNC SUPPORTS LIGHT
FOG/HAZE LATE TONIGHT WITH WINDS DECOUPLING AND GRADUALLY INCREASING
LOW LVL MSTR.
LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 330 AM SAT...GENERALLY EXPECT VFR CONDITIONS WITH ONLY
OCCASIONAL PERIODS OF SHOWERS/STORMS PRODUCING MVFR CONDITIONS
THROUGH THE LONG TERM PERIOD. MAY BE SOME LIGHT FOG/STRATUS EACH
NIGHT IN THE LONG TERM AS WINDS WILL BE LIGHT TO CALM EACH EVENING.
&&
.MARINE...
SHORT TERM /THROUGH TONIGHT/...
AS OF 945 AM SATURDAY...FORECAST LOOKS GOOD. NO CHANGES NEEDED.
ISOLATED SHOWERS ACROSS THE NORTHERN WATERS THIS MORNING. SEAS 2
FEET AND SW/W FLOW AROUND 5-10KTS.
/PREVIOUS DISCUSSION/
AS OF 400 AM SATURDAY...PRES GRADIENT BETWEEN INLAND TROF AND
OFFSHORE HIGH PRESSURE WILL TIGHTEN SLIGHTLY WITH HEATING
TODAY...RESULTING IN S-SW WINDS INCREASING TO 10-15 KT THIS AFTN
AND GRADUALLY DIMINISH OVERNIGHT. SEAS GENERALLY REMAINING AROUND
2 FT.
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 330 AM SAT...THE PERIOD BEGINS WITH SOUTH TO SW FLOW THAT INC
A BIT ON SUN AS GRADIENT INC. IN GENERAL FLOW WILL REMAIN SOUTHERLY
INCREASING TO AROUND 15 KT SUNDAY AFTERNOON THROUGH SUNDAY NIGHT.
COULD SEE A FEW 4 FOOT SEAS IN THE OUTER WATERS IN THIS TIME FRAME.
MONDAY AFTERNOON INTO TUE THE GRADIENT WILL TIGHTEN FURTHER AS AN
AREA OF LOW PRESSURE TRACKS TO OUR NORTH WITH S TO SW FLOW
INCREASING TO 15 TO 20 KT AHEAD OF A TRAILING COLD FRONT. THIS WILL
ALLOW SEAS TO BUILD TO 4 TO 5 FEET ACROSS CENTRAL AND SOUTHERN OUTER
WATERS. THE COLD FRONT PASSES THROUGH THE WATERS TUE NIGHT AND
DISSIPATES BRINGING LIGHTER WINDS RETURNING TO SOUTHERLY BY LATE
WEDNESDAY AND SEAS RETURNING TO 2 TO 3 FEET. SOME DISAGREEMENT
TOWARDS THE END OF NEXT WEEK AS GFS BRINGS GUSTY NE WINDS TO THE
AREA...HOWEVER MORE LIKELY SCENARIO IS FOR WINDS TO REMAIN S TO SW
AS HIGH PRES REMAINS IN CONTROL OF THE SE SEABOARD AND CONDITIONS TO
REMAIN SUB SCA.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JBM
NEAR TERM...JBM/LEP
SHORT TERM...JBM
LONG TERM...TL
AVIATION...JBM/TL
MARINE...JBM/TL/LEP
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
739 AM EDT SAT AUG 16 2014
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND OVER THE AREA FROM OFFSHORE THROUGH
EARLY NEXT WEEK WITH A TROUGH OF LOW PRESSURE INLAND. A WEAK COLD
FRONT WILL MOVE IN FROM THE NORTH TUESDAY NIGHT...THEN RETURN
NORTH WEDNESDAY.
&&
.NEAR TERM /TODAY/...
AS OF 715 AM SATURDAY...EXTENDED 20 POP ACROSS NRN HALF OF AREA THIS
MORNING AND ADJUSTED SKY COVER BASED ON LATEST STLT TRENDS.
CONVECTIVE ACTIVITY STILL MOVING ACROSS JUST N OF AREA AND CANNOT
RULE OUT ISOLATED SHOWER NRN SECTIONS WITH SHRT WV MOVING ACROSS AND
WEAK SFC BNDRY IN VCTY. REST OF FCST ON TRACK.
/PREVIOUS DISCUSSION/
AS OF 400 AM SATURDAY...ISOLATED SHOWER/TSTM THREAT WILL CONTINUE
ACROSS NRN HALF OF AREA THROUGH 8 AM AS ADDITIONAL ACTIVITY
DEVELOPING SOUTH OF MAIN AREA NEAR NC/VA LINE. HRRR HAS GOOD HANDLE
ON THIS ACTIVITY. ISOLATED THREAT PSBL OVER NE SECTIONS 8 AM TIL
NOON AND CONTINUED PREVIOUS FCST 20 POP THERE. SHRT WV
ENERGY...HEATING...INLAND TROF AND SEA BREEZE SUPPORT ISOLATED
SHOWERS/TSTMS INLAND OF COAST THIS AFTN. HIGH TEMPS AROUND 90 INLAND
WITH MID 80S OBX.
&&
.SHORT TERM /TONIGHT/...
AS OF 400 AM SATURDAY...ISOALATED CONVECTIVE THREAT WILL CONTINUE
INLAND THIS EVENING...WITH ANOTHER SHRT WV MOVING IN FROM W-NW.
MODELS SUPPORT ACTIVITY DIMINISHING OVERNIGHT...BUT SOME
REDEVELOPMENT PSBL ALONG COAST NEAR MORNING...THUS NO CHANGE TO
PREVIOUS FCST. MIN TEMPS FROM AROUND 70 INLAND TO MID 70S COAST.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
AS OF 330 AM SAT...LONG TERM PERIOD WILL BE DOMINATED BY WARMING
TEMPERATURE PATTERN WITH OCCASIONAL BOUTS OF SHOWERS AND
THUNDERSTORMS.
LOW LEVEL SFC FLOW RETURNS TO THE AREA THIS WEEKEND WITH INCREASING
TEMPS...THOUGH DEWPOINTS WILL BE A BIT SLOWER TO RESPOND SO STILL
EXPECTING NEAR CLIMO LOWS OVERNIGHT. CONTINUED TYPICAL SUMMERY
PATTERN ON SUNDAY WITH ISOLATED AFTERNOON THUNDERSHOWERS ALONG SEA
BREEZE FRONT.
MED/LONG RANGE MODELS IN FAIRLY GOOD AGREEMENT WITH RESPECT TO
SYNOPTIC REGIME THROUGH THE LONG TERM...WITH SLOWLY BUILDING HEIGHTS
AS MID ATLANTIC RIDGE BUILDS INTO THE DEEP SOUTH. THIS WILL BRING
HOT TEMPS AND HIGH HUMIDITY VALS AS LAYER MIX RATIOS INC TO AROUND
16 G/KG EARLY TO MID NEXT WEEK. THE REGION LOOKS TO REMAIN JUST
SOUTH OF THE STORM TRACK...THOUGH COULD BE AFFECTED BY A SYSTEM
EXPECTED TO TRAVERSE THE MID ATLANTIC REGION IN THE MON NIGHT TO TUE
TIME FRAME AND THEN AGAIN MID TO LATE WEEK.
FOR MONDAY AFTERNOON AND EVENING...HAVE AN INCREASING POP TREND AS
MODEL SUITE IS IN GOOD AGREEMENT ON A COMPACT SHORTWAVE TRAVERSING
THE MID ATLANTIC STATES...WITH SFC REFLECTION NOTED ACROSS THE
DELMARVA PENINSULA MON NIGHT. TRICKY TO PIN DOWN WHERE/WHEN
DEVELOPMENT WILL TAKE PLACE IN THIS CONVECTIVE REGIME...SO HAVE
CAPPED POPS IN THE CHANCE RANGE...LOWEST ACROSS THE SOUTHERN FA.
POTENTIAL MCS ACTIVITY COULD BRING A GOOD AMOUNT OF QPF TO PARTS OF
E NC THROUGH MON NIGHT. IN ADDITION...LAYER MIX RATIOS INC QUITE A
BIT INTO THE 17 G/KG RANGE WITH PWATS AROUND 2 INCHES. THE LOW MOVES
OFFSHORE ON TUE WITH ATTENDANT TRAILING COLD FRONT PUSHING INTO THE
AREA. KEPT CHANCE POPS TUE AS ANOTHER ROUND OF SHOWERS/STORMS COULD
AFFECT THE AREA AHEAD OF THE FRONT.
WED WILL MOST LIKELY BE A DRY DAY AS SUBSIDENCE TAKES PLACE BEHIND
EXITING LOW/SHORTWAVE BUT HAVE KEPT SLIGHT CHANCE POPS IN FCST AS
THERE IS STILL INSTABILITY PRESENT DUE TO A WARM AND MUGGY AIRMASS
IN PLACE.
THUR INTO NEXT WEEKEND...RIDGE BUILDS ACROSS THE CENTRAL CONUS
ALLOWING FOR UPR FLOW TO BECOME MORE NW ACROSS THE EASTERN SEABOARD.
THIS WILL BRING BOUTS OF NW FLOW CONVECTION WITH H85 MB BAROCLINIC
ZONE LOCATED IN THE VCNTY. HAVE PAINTED LOW CHANCE POPS FOR THIS
PERIOD AS OCNL SHORTWAVE ACTIVITY WILL AFFECT THE AREA.
TEMPS DURING THE PERIOD WILL BE QUITE WARM AND ABOVE CLIMO...WITH
THICKNESSES SUGGESTING HIGHS IN THE LOW TO OCNL MID 90S PERHAPS AT
TIMES. LOWS WILL BE MUGGY IN THE 70S.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM /THROUGH 12Z SUNDAY/...
AS OF 720 AM SATURDAY...VFR EXPECTED THROUGH THIS EVENING...THEN
PERIOD OF MVFR VSBYS LIKELY LATE TONIGHT MOST SITES. ISOLATED
CONVECTIVE ACTIVITY PSBL WITH SEA BREEZE AND INLAND TROFFING BUT
COVERAGE TOO LIMITED TO MENTION IN TAFS. LATEST GDNC SUPPORTS LIGHT
FOG/HAZE LATE TONIGHT WITH WINDS DECOUPLING AND GRADUALLY INCREASING
LOW LVL MSTR.
LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 330 AM SAT...GENERALLY EXPECT VFR CONDITIONS WITH ONLY
OCCASIONAL PERIODS OF SHOWERS/STORMS PRODUCING MVFR CONDITIONS
THROUGH THE LONG TERM PERIOD. MAY BE SOME LIGHT FOG/STRATUS EACH
NIGHT IN THE LONG TERM AS WINDS WILL BE LIGHT TO CALM EACH EVENING.
&&
.MARINE...
SHORT TERM /THROUGH TONIGHT/...
AS OF 715 AM SATURDAY...EXTENDED SLIGHT CHANCE OF SHOWERS OVER NRN
WATERS THIS MORNING...NO CHAGNES TO WINDS/SEAS.
/PREVIOUS DISCUSSION/
AS OF 400 AM SATURDAY...PRES GRADIENT BETWEEN INLAND TROF AND
OFFSHORE HIGH PRESSURE WILL TIGHTEN SLIGHTLY WITH HEATING
TODAY...RESULTING IN S-SW WINDS INCREASING TO 10-15 KT THIS AFTN AND
GRADUALLY DIMINISH OVERNIGHT. SEAS GENERALLY REMAINING AROUND 2 FT.
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 330 AM SAT...THE PERIOD BEGINS WITH SOUTH TO SW FLOW THAT INC
A BIT ON SUN AS GRADIENT INC. IN GENERAL FLOW WILL REMAIN SOUTHERLY
INCREASING TO AROUND 15 KT SUNDAY AFTERNOON THROUGH SUNDAY NIGHT.
COULD SEE A FEW 4 FOOT SEAS IN THE OUTER WATERS IN THIS TIME FRAME.
MONDAY AFTERNOON INTO TUE THE GRADIENT WILL TIGHTEN FURTHER AS AN
AREA OF LOW PRESSURE TRACKS TO OUR NORTH WITH S TO SW FLOW
INCREASING TO 15 TO 20 KT AHEAD OF A TRAILING COLD FRONT. THIS WILL
ALLOW SEAS TO BUILD TO 4 TO 5 FEET ACROSS CENTRAL AND SOUTHERN OUTER
WATERS. THE COLD FRONT PASSES THROUGH THE WATERS TUE NIGHT AND
DISSIPATES BRINGING LIGHTER WINDS RETURNING TO SOUTHERLY BY LATE
WEDNESDAY AND SEAS RETURNING TO 2 TO 3 FEET. SOME DISAGREEMENT
TOWARDS THE END OF NEXT WEEK AS GFS BRINGS GUSTY NE WINDS TO THE
AREA...HOWEVER MORE LIKELY SCENARIO IS FOR WINDS TO REMAIN S TO SW
AS HIGH PRES REMAINS IN CONTROL OF THE SE SEABOARD AND CONDITIONS TO
REMAIN SUB SCA.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JBM
NEAR TERM...JBM
SHORT TERM...JBM
LONG TERM...TL
AVIATION...JBM/TL
MARINE...JBM/TL
AREA FORECAST DISCUSSION
NWS BISMARCK ND
915 AM CDT SAT AUG 16 2014
.UPDATE...
ISSUED AT 915 AM CDT SAT AUG 16 2014
GIVEN RADAR TRENDS THROUGH 14 UTC...THE 10-11 UTC HRRR ITERATIONS
AND 00 UTC WRF-ARW/NMM SOLUTIONS...THE FOCUS FOR HEAVY RAINFALL
THIS MORNING AND AFTERNOON WILL BE ACROSS THE PRAIRIE POT HOLE
REGION OF SOUTH CENTRAL NORTH DAKOTA...SHIFTING INTO THE JAMES
RIVER VALLEY IN THE SOUTHEAST QUADRANT OF THE MESO-LOW EVIDENT ON
RADAR ACROSS THE HIGHWAY 83 CORRIDOR THIS MORNING. FLASH FLOOD
GUIDANCE IS IN THE 2-3 INCH PER HOUR RANGE FOR THESE AREAS.
ACROSS THE WEST...ESPECIALLY FOR THOSE AREAS WHICH WERE IMPACTED
BY VERY HEAVY RAIN OVER THE PAST 24-36 HOURS...MUCH OF THE DAY
WILL BE RATHER PRECIPITATION FREE. THE MAIN CONCERN IS FOR THIS
EVENING AND TONIGHT AS ANOTHER ROUND OF THUNDERSTORMS IS FORECAST
TO PROPAGATE INTO THE AREA FROM EASTERN MONTANA AS UPPER LEVEL
FORCING INCREASES AHEAD OF THE UPPER LEVEL LOW ACROSS THE NORTHERN
ROCKIES. FLASH FLOOD GUIDANCE IS WELL BELOW ONE INCH FOR MOST AREAS
ALREADY IMPACTED BY HEAVY RAIN...WITH ANY ADDITIONAL RAINFALL
AGGRAVATING THE ONGOING FLOODING.
UPDATE ISSUED AT 625 AM CDT SAT AUG 16 2014
BROAD AREA OF PRECIP CONTINUES TO STRETCH FROM NORTHWESTERN TO
SOUTH CENTRAL NORTH DAKOTA. GOING FORECAST ADDRESSES THIS WELL.
ONLY CHANGES MADE WERE TO PULL AREAS OF FOG FURTHER NORTH AND
WEST TO MATCH CURRENT OBS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CDT SAT AUG 16 2014
ISSUES IN THE SHORT TERM ARE ALL HYDROLOGIC WHICH IS BEING
FOCUSED ON IN THIS SHORT TERM SECTION.
LATEST RADAR TRENDS ARE FINALLY SHOWING A SLIGHT EASTWARD PUSH TO
THE LARGE AREA OF HEAVY RAIN OVER THE CENTRAL PART OF WESTERN
NORTH DAKOTA. THIS WILL BE WELCOME NEWS TO THE FOLKS IN DUNN
COUNTY WHERE SIGNIFICANT OVERLAND FLOODING WAS OCCURRING. THE
FLOOD WARNING CONTINUES FOR THAT CENTRAL PART OF WESTERN NORTH
DAKOTA THROUGH THE DAY SATURDAY. AS THE BACK EDGE OF THE RAIN AREA
WAS SHOWING A SLIGHT PUSH TO THE EAST...THE EASTERN EDGE OF THE
RAIN WAS ADVANCING MORE QUICKLY THROUGH MCLEAN AND MERCER
COUNTIES. AT THE SAME TIME NEW SHOWER/STORM DEVELOPMENT WAS
OCCURRING IN THE MANDAN-BISMARCK-STEELE AREAS.
DIFFLUENT FLOW ALOFT CONTINUES TODAY WITH SHORT WAVE ENERGY
ROTATING AROUND THE MAIN CLOSED H5 LOW IN SOUTHERN ALBERTA CANADA.
THIS MEANS A CONTINUED HIGH CHANCE FOR RAIN ACROSS THE WESTERN AND
CENTRAL PARTS OF THE FORECAST AREA INTO THIS AFTERNOON...SHIFTING
EAST BY LATE DAY.
OVERLAND FLOOD WARNING CONTINUES FOR MCKENZIE...DUNN...GOLDEN VALLEY...
BILLINGS...STARK...AND WESTERN MERCER AND WESTERN MORTON COUNTIES
THROUGH THE AFTERNOON.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 345 AM CDT SAT AUG 16 2014
MAIN CHALLENGE FOR THE EXTENDED IS CONTINUED PRECIPITATION CHANCES
TO START THE UPCOMING WEEK. CENTER OF UPPER LOW WILL PUSH ACROSS
SOUTHERN SASKATCHEWAN ON SUNDAY...AND THROUGH SOUTHERN MANITOBA
SUNDAY NIGHT INTO EARLY MONDAY. EXPECT PRECIP FOCUS TO START OUT
IN WEST-CENTRAL DURING THE DAY ON SUNDAY...THEN WORK TOWARDS THE
EAST SUNDAY NIGHT/EARLY MONDAY WITH PRECIP TAPERING FROM WEST TO
EAST THROUGH THE DAY ON MONDAY. EXPECT A QUIET PERIOD ON TUESDAY
AS FAST MOVING RIDGE PASSES OVER BEHIND DEPARTING SYSTEM BEFORE
SOUTHWESTERLY FLOW SETS UP OVER THE AREA. MODELS DIFFER SOME ON
HOW STRONG THIS FLOW IS...BUT THE MAIN POINT IS THAT THIS WILL
BRING THE NEXT ROUND OF PRECIPITATION CHANCES TO THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 915 AM CDT SAT AUG 16 2014
WIDESPREAD MVFR CIGS AND VIS WITH LCL IFR VIS IN HEAVIER PRECIP WILL
CONTINUE THROUGH THIS MORNING OVER MUCH OF NORTHWEST INTO PARTS OF
SOUTH CENTRAL NORTH DAKOTA AS SHRA/TSRA CONTINUE TO MOVE THROUGH
THE AREA. PRECIPITATION WILL SLOWLY DEVELOP TOWARDS THE EAST TODAY
POSSIBLY BRINGING VISIBILITY RESTRICTIONS FURTHER INTO CENTRAL
NORTH DAKOTA. AREAS OF FOG WILL ALSO BRING VISIBILITY RESTRICTIONS
OVER PARTS OF CENTRAL AND EASTERN NORTH DAKOTA EARLY THIS MORNING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...JPM
LONG TERM...JJS
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1120 AM EDT SAT AUG 16 2014
.SYNOPSIS...
THE UNSEASONABLY DEEP TROUGH AND COOL DRY AIR WILL SHIFT TO OUR
EAST. A NORTHWEST FLOW PATTERN WILL DEVELOP. THE MODELS SHOW TWO
SHORTWAVES IN THE NW FLOW TO AFFECT THE REGION. FIRST ONE SUNDAY
AND THE SECOND ONE ABOUT TUESDAY. AT THIS TIME THE SECOND ONE
LOOKS WETTER. THE EVOLVING HIGH LATITUDE BLOCKING 500 HPA HIGH
COULD KEEP MAIN SHORTWAVE TRACK SUPPRESSED TO OUR SOUTH. THE
DEVELOPING 5900M RIDGE OVER THE SOUTHERN USA THIS WEEK SHOULD NOT
AFFECT US OTHER THAN KEEPING THE REGION IN NW FLOW.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
CIRRUS SHIELD CONTINUES TO WORK ITS AWAY ACROSS THE STATE FROM
NORTHWEST TO SOUTHEAST. MOST AREAS WILL SEE PEAKS OF SUN AS HIGH
CLOUDS MOVE BY.
MORE CIRRUS WITH THE WEAK BUT FAST MOVING SHORTWAVE APPROACHES
FROM THE NORTHWEST THIS EVENING INTO SUNDAY. THE NCEP PARALLEL 3
KM HRRR RADAR SIMULATIONS IMPLY THE RAIN WOULD JUST BE ALONG THE
NORTHWEST PA/NY BORDER ABOUT 8 PM AND THEN SHOWS SHOWERS MOVING
INTO NORTHWESTERN PA SHORTLY THERE AFTER. BUT HRRR IMPLIES SHOWERS
POSSIBLE ALONG NY BORDER WARREN/MCKEAN FROM ABOUT 7 PM ON.
PUMPED POPS TO CHANCE UP THERE LATER AFTERNOON IN CASE HRRR IS
SLOW.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM SUNDAY/...
THE 3KM HRRR IMPLIES THIS IS THE BEST CHANCE FOR SHOWERS AND
ISOLATED THUNDERSTORMS IN PA. THE TIMING ALSO FALLS INTO THE HIGH
PROBABILITY PART OF THE 09Z SREF. THE SREF PDF FOR ACCUMULATING
RAINFALL PEAKS IN THE 0000 TO 1200 UTC TIMEFRAME IN NW PA WITH
RAIN LIKELY. HRRR AND SREF ARE COMPLIMENTARY.
THE SREF SHOWS THE RAINFALL PDF DROPPING AS THE WAVE MOVES INTO
CENTRAL AREAS IN THE 6 TO 18Z RANGE. TRIED TO SHOW IMPROVING
CONDITIONS AND POTENTIALLY A RELATIVELY NICE AFTERNOON OVER MOST
OF CENTRAL AND NORTHERN PA SUNDAY.
THE TREND APPEARS TO BE THIS WAVE IS WEAKER AND NOT AS WET AS
EARLIER RUNS AND SUNDAY IS STARTING TO LOOKS BETTER AS THE DAY
MOVES ON. AT THIS TIME THE SREF IMPLIES RESIDUAL SHOWERS NEAR MD
BORDER AND SOUTH MUCH AFTER 15-18Z SO DROPPED POPS.
SEE HOW 4KM NAM LATER THIS MORNING AND NAM SHOW CONVECTION.
BOTTOM LINE SUNDAY IS LOOKING LIKE BEST CHANCE RAIN EARLY IN
DAY/MORNING WITH SCATTERED SHOWERS SHIFTING RAPIDLY SOUTH. MOST
AREAS SHOULD BE RAIN FREE MOST OF THE DAY. OTHER THAN NW PA RAIN
WOULD BE VERY LIGHT TOO. AND IN NW LOOKING AT 0.10 TO 0.20.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
BIG EVENT OF WEEK COULD BE RAINFALL TUESDAY....
HIGHEST PROBABILITY OF RAIN THROUGH 8 AM SUNDAY WOULD BE NORTHERN
PA. LOW PROBABILITY OF OVER 1.00 INCH OF RAINFALL IN NORTHERN
AREAS. ENSEMBLES SUGGEST 30 PERCENT OF MEMBERS HAVE MUCH MORE THAN
0.75 INCHES OF QPF.
SUNDAY MODELS FOCUS HIGHER PROBABILITIES IN CENTRAL AND SOUTHERN
PA. MOST AREAS OVER THE PERIOD SUNDAY WILL LIKELY SEE 0.10 TO 0.50
INCHES OF RAIN AS FRONT SAGS SOUTHWARD.
DRY AIR MOVING BEHIND FRONT COULD PROVIDE SOME SUN IN CENTRAL
NORTHERN AREAS IN AFTERNOON SUNDAY.
MONDAY SHOULD START OFF RELATIVELY DRIER...SREF/GEFS AND
DETERMINISTIC MODELS SHOW A STRONG WARM SEASON WAVE COMING IN
FROM THE WEST RELATIVELY FAST. THIS WAVE SHOULD SPREAD MORE CLOUDS
AND BRING RAIN WEST TO EAST ACROSS PA MONDAY INTO OVERNIGHT
TUESDAY.
EARLY WEEK RAIN SHOULD BE MAIN EVENT...
THE RAIN EVENT OVERNIGHT MONDAY INTO TUESDAY AS FORECAST IS THE
MAIN EVENT OF THE COMING WEEK. DEEP CLIPPER-LIKE CYCLONE...EAST-
WEST BOUNDARY...HIGH PW AND EASTERLY FLOW NORTH OF THE CYCLONE.
THIS COULD BE A HEAVY RAIN EVENT WITH A SYNOPTIC TYPE (S-N FLOW)
EVOLVING TO A FRONTAL TYPE WITH EASTERLY FLOW. EVEN CRUDE GEFS
SHOWS EASTERLY WIND ANOMALIES. GEFS IMPLIES GOOD 1 TO 2 INCH
RAINFALL IS POSSIBLE. THIS EVENT HAS POTENTIAL TO BE A SIGNIFICANT
RAINFALL EVENT.
LARGER SCALE MODELS SHOW NO SIGNIFICANT CAPE. RAIN/SHOWERS AND
PERHAPS ELEVATED CONVECTION WITH THIS EVENT. DUE TO TIME RANGE AND
PREDICTABILITY HORIZON DID NOT GO BIG IN QPF GRIDS AT THIS TIME.
SUSPECT IF THIS SYSTEM DEVELOPS AS FORECAST...OUR HIGHS TUESDAY
COULD GET CRUSHED. BUT AT THIS TIME THIS IS THE EVENT TO MONITOR.
AS THIS SYSTEM SLOWLY GOES BY RAINFALL SHOULD DIMINISH TUESDAY
AND WEDNESDAY. WEDNESDAY AS FORECAST LOOKS RELATIVELY DRY. THEN PW
VALUES RISE AGAIN.
LATER PART OF WEEK LOOKS POTENTIALLY SHOWERY. THE LARGE 500 HPA
RIDGE RETROGRADING TO A POSITION NORTH OF THE GREAT LAKES WILL
LIKELY ALLOW MOISTURE INTO OUR REGION AND KEEP A LARGER SCALE
FRONTAL BOUNDARY NEARBY. THE CMCEFS AND GEFS WILL LIKELY NOT
CAPTURE ANY SHORT WAVES CUTTING UNDER THIS BLOCK. KEPT POPS IN
CHANCE RANGE MOST OF THE TIME. PRETTY UNSETTLED AND RELATIVELY WET
PATTERN LAST PART OF THE COMING WORK WEEK.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
THE CIRRUS MAY HAVE SLOWED DOWN THE BURNING OFF OF THE FOG AT KIPT
BUT IT IS FINALLY VFR AT KIPT AND WILL BE SO FOR THE REST OF THE
DAY.
CIRRUS WILL STREAM BY TODAY WELL ABOVE 20KFT AND MORE CIRRUS
HEADED OUR WAY OVERNIGHT...ALONG WITH SOME SHOWER ACTIVITY MAINLY
AFTER 00Z SUNDAY. BEST CHANCE RAIN SHOWERS MVFR/IFR WILL BE IN NW
PA OVERNIGHT AND THEN SLIDING SOUTH.
MOST AREAS WILL BE VFR WITH PERIODS MVFR BEFORE AND JUST AFTER
SUNRISE SUNDAY. RAIN SHOWERS WEAKEN SUNDAY AND SHOULD NOT BE
SERIOUS ISSUE. MOST OF THE TIME...AFTER 14-15Z SHOULD BE MAINLY
VFR.
PATCHY FOG OVERNIGHT SUNDAY INTO MONDAY AND POTENTIAL RAIN EVENT
MONDAY NIGHT INTO TUESDAY COULD BRING SOME MVFR/IFR CONDITIONS
INTO THE REGION.
OUTLOOK... SUN...AM LOW CIGS/SHRA POSSIBLE AT
KBFD. MON...AM FOG POSSIBLE N MTNS...THEN SCATTERED SHOWERS.
TUE...RAIN/LOW CIGS POSSIBLE...MAINLY SOUTHERN PA. WED...SCT PM
TSRA IMPACTS POSSIBLE W MTNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM
LONG TERM...GRUMM
AVIATION...GRUMM
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1051 AM EDT SAT AUG 16 2014
.SYNOPSIS...
THE UNSEASONABLY DEEP TROUGH AND COOL DRY AIR WILL SHIFT TO OUR
EAST. A NORTHWEST FLOW PATTERN WILL DEVELOP. THE MODELS SHOW TWO
SHORTWAVES IN THE NW FLOW TO AFFECT THE REGION. FIRST ONE SUNDAY
AND THE SECOND ONE ABOUT TUESDAY. AT THIS TIME THE SECOND ONE
LOOKS WETTER. THE EVOLVING HIGH LATITUDE BLOCKING 500 HPA HIGH
COULD KEEP MAIN SHORTWAVE TRACK SUPPRESSED TO OUR SOUTH. THE
DEVELOPING 5900M RIDGE OVER THE SOUTHERN USA THIS WEEK SHOULD NOT
AFFECT US OTHER THAN KEEPING THE REGION IN NW FLOW.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
CIRRUS SHIELD CONTINUES TO WORK ITS AWAY ACROSS THE STATE FROM
NORTHWEST TO SOUTHEAST. MOST AREAS WILL SEE PEAKS OF SUN AS HIGH
CLOUDS MOVE BY.
MORE CIRRUS WITH THE WEAK BUT FAST MOVING SHORTWAVE APPROACHES
FROM THE NORTHWEST THIS EVENING INTO SUNDAY. THE NCEP PARALLEL 3
KM HRRR RADAR SIMULATIONS IMPLY THE RAIN WOULD JUST BE ALONG THE
NORTHWEST PA/NY BORDER ABOUT 8 PM AND THEN SHOWS SHOWERS MOVING
INTO NORTHWESTERN PA SHORTLY THERE AFTER. BUT HRRR IMPLIES SHOWERS
POSSIBLE ALONG NY BORDER WARREN/MCKEAN FROM ABOUT 7 PM ON.
PUMPED POPS TO CHANCE UP THERE LATER AFTERNOON IN CASE HRRR IS
SLOW.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM SUNDAY/...
THE 3KM HRRR IMPLIES THIS IS THE BEST CHANCE FOR SHOWERS AND
ISOLATED THUNDERSTORMS IN PA. THE TIMING ALSO FALLS INTO THE HIGH
PROBABILITY PART OF THE 09Z SREF. THE SREF PDF FOR ACCUMULATING
RAINFALL PEAKS IN THE 0000 TO 1200 UTC TIMEFRAME IN NW PA WITH
RAIN LIKELY. HRRR AND SREF ARE COMPLIMENTARY.
THE SREF SHOWS THE RAINFALL PDF DROPPING AS THE WAVE MOVES INTO
CENTRAL AREAS IN THE 6 TO 18Z RANGE. TRIED TO SHOW IMPROVING
CONDITIONS AND POTENTIALLY A RELATIVELY NICE AFTERNOON OVER MOST
OF CENTRAL AND NORTHERN PA SUNDAY.
THE TREND APPEARS TO BE THIS WAVE IS WEAKER AND NOT AS WET AS
EARLIER RUNS AND SUNDAY IS STARTING TO LOOKS BETTER AS THE DAY
MOVES ON. AT THIS TIME THE SREF IMPLIES RESIDUAL SHOWERS NEAR MD
BORDER AND SOUTH MUCH AFTER 15-18Z SO DROPPED POPS.
SEE HOW 4KM NAM LATER THIS MORNING AND NAM SHOW CONVECTION.
BOTTOM LINE SUNDAY IS LOOKING LIKE BEST CHANCE RAIN EARLY IN
DAY/MORNING WITH SCATTERED SHOWERS SHIFTING RAPIDLY SOUTH. MOST
AREAS SHOULD BE RAIN FREE MOST OF THE DAY. OTHER THAN NW PA RAIN
WOULD BE VERY LIGHT TOO. AND IN NW LOOKING AT 0.10 TO 0.20.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
BIG EVENT OF WEEK COULD BE RAINFALL TUESDAY....
HIGHEST PROBABILITY OF RAIN THROUGH 8 AM SUNDAY WOULD BE NORTHERN
PA. LOW PROBABILITY OF OVER 1.00 INCH OF RAINFALL IN NORTHERN
AREAS. ENSEMBLES SUGGEST 30 PERCENT OF MEMBERS HAVE MUCH MORE THAN
0.75 INCHES OF QPF.
SUNDAY MODELS FOCUS HIGHER PROBABILITIES IN CENTRAL AND SOUTHERN
PA. MOST AREAS OVER THE PERIOD SUNDAY WILL LIKELY SEE 0.10 TO 0.50
INCHES OF RAIN AS FRONT SAGS SOUTHWARD.
DRY AIR MOVING BEHIND FRONT COULD PROVIDE SOME SUN IN CENTRAL
NORTHERN AREAS IN AFTERNOON SUNDAY.
MONDAY SHOULD START OFF RELATIVELY DRIER...SREF/GEFS AND
DETERMINISTIC MODELS SHOW A STRONG WARM SEASON WAVE COMING IN
FROM THE WEST RELATIVELY FAST. THIS WAVE SHOULD SPREAD MORE CLOUDS
AND BRING RAIN WEST TO EAST ACROSS PA MONDAY INTO OVERNIGHT
TUESDAY.
EARLY WEEK RAIN SHOULD BE MAIN EVENT...
THE RAIN EVENT OVERNIGHT MONDAY INTO TUESDAY AS FORECAST IS THE
MAIN EVENT OF THE COMING WEEK. DEEP CLIPPER-LIKE CYCLONE...EAST-
WEST BOUNDARY...HIGH PW AND EASTERLY FLOW NORTH OF THE CYCLONE.
THIS COULD BE A HEAVY RAIN EVENT WITH A SYNOPTIC TYPE (S-N FLOW)
EVOLVING TO A FRONTAL TYPE WITH EASTERLY FLOW. EVEN CRUDE GEFS
SHOWS EASTERLY WIND ANOMALIES. GEFS IMPLIES GOOD 1 TO 2 INCH
RAINFALL IS POSSIBLE. THIS EVENT HAS POTENTIAL TO BE A SIGNIFICANT
RAINFALL EVENT.
LARGER SCALE MODELS SHOW NO SIGNIFICANT CAPE. RAIN/SHOWERS AND
PERHAPS ELEVATED CONVECTION WITH THIS EVENT. DUE TO TIME RANGE AND
PREDICTABILITY HORIZON DID NOT GO BIG IN QPF GRIDS AT THIS TIME.
SUSPECT IF THIS SYSTEM DEVELOPS AS FORECAST...OUR HIGHS TUESDAY
COULD GET CRUSHED. BUT AT THIS TIME THIS IS THE EVENT TO MONITOR.
AS THIS SYSTEM SLOWLY GOES BY RAINFALL SHOULD DIMINISH TUESDAY
AND WEDNESDAY. WEDNESDAY AS FORECAST LOOKS RELATIVELY DRY. THEN PW
VALUES RISE AGAIN.
LATER PART OF WEEK LOOKS POTENTIALLY SHOWERY. THE LARGE 500 HPA
RIDGE RETROGRADING TO A POSITION NORTH OF THE GREAT LAKES WILL
LIKELY ALLOW MOISTURE INTO OUR REGION AND KEEP A LARGER SCALE
FRONTAL BOUNDARY NEARBY. THE CMCEFS AND GEFS WILL LIKELY NOT
CAPTURE ANY SHORT WAVES CUTTING UNDER THIS BLOCK. KEPT POPS IN
CHANCE RANGE MOST OF THE TIME. PRETTY UNSETTLED AND RELATIVELY WET
PATTERN LAST PART OF THE COMING WORK WEEK.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
HIGHLY VARIABLE FOG CONDITIONS CONTINUE ACROSS THE AREA...WITH
SOME LOCATIONS IN LIFR CONDITIONS...AND A GOOD DEAL OF OTHER
LOCATIONS VFR.
LIMITED NATURE OF FOG SHOULD PRECLUDE IT LASTING MUCH PAST 13Z OR
14Z. THEN VFR CONDITIONS WITH JUST SOME HIGH CLOUDS WILL PREVAIL
THE REST OF THE DAY.
NEXT APPROACHING FRONTAL SYSTEM WILL SHOWERS TO WESTERN AND
NORTHWESTERN AREAS AROUND 06Z...SPREADING INTO CENTRAL AREAS
BEFORE 12Z SUNDAY. THIS WILL ACCOMPANIED BY LOWERING VSBYS AND
CIGS. EXPECT WIDESPREAD MVFR CONDITIONS ACROSS WESTERN AND CENTRAL
AREAS BEFORE 12Z SUNDAY.
OUTLOOK...
SUN...AM LOW CIGS/SHRA POSSIBLE AT KBFD.
MON...AM FOG POSSIBLE N MTNS...THEN SCATTERED SHOWERS.
TUE...RAIN/LOW CIGS POSSIBLE...MAINLY SOUTHERN PA.
WED...SCT PM TSRA IMPACTS POSSIBLE W MTNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM
LONG TERM...GRUMM
AVIATION...JUNG
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
539 AM CDT SAT AUG 16 2014
.DISCUSSION...
SEE AVIATION FOR 12Z TAF ISSUANCE.
&&
.AVIATION...
HIGH PRESSURE OVER THE GULF OF MEXICO WILL ALLOW SOUTHERLY WINDS
TO CONTINUE TODAY. THE SEA BREEZE IS AGAIN EXPECTED TO MOVE INLAND
TODAY PRODUCING ISOLATED SHOWERS AND THUNDERSTORMS. THE TEXAS TECH
WRF SEEMS A BIT OVER DONE FOR TODAY BUT THE HIGH RES RAP AND HRRR
MODEL SEEM MORE ON PAR KEEPING THE COVERAGE ISOLATED. SOME STORMS
COULD MAKE IT FARTHER INLAND TODAY AS PWATS HAVE CONTINUED THEIR
SLOW CLIMB. MOSTLY VFR CONDITIONS EXPECTED THROUGH THE ISSUANCE.
23
&&
.PREV DISCUSSION... /ISSUED 456 AM CDT SAT AUG 16 2014/
DISCUSSION...
SCATTERED SHOWERS DEVELOPING ACROSS THE COASTAL WATERS THIS
MORNING SO FAR MAINLY SOUTHEAST OF LINE FROM HIGH ISLAND TO 40 NM
SOUTH OF FREEPORT. ANOTHER HOT AUGUST DAY ON TAP WITH RIDGING
INFLUENCE STILL PRESENT AND EXPECT TEMPERATURES TO REACH INTO THE
UPPER 90S AND HEAT INDEX READINGS OF 101 TO 105 BEING COMMON THIS
AFTERNOON AND AGAIN SUNDAY...PERHAPS A DEGREE OR TWO HOTTER
SUNDAY. RAIN CHANCES LOOK SLIM TODAY AGAIN AND WILL PROBABLY ONLY
SEE A FEW SHOWERS DOT THE SOUTHERN AREAS.
SUNDAY GETS MORE INTERESTING WITH THE UPPER SHEAR AXIS IN THE GULF
MOVING WEST AND A S/W MOVING UP INTO THE AREA FROM THE SOUTH AND
ANOTHER FROM THE WEST. PRECIPITABLE WATER VALUES CLIMB TO 1.8-2.1"
AND INSTABILITY INCREASES. EXPECT SCATTERED SHOWERS IN THE MORNING
TO TRANSITION TO MORE THUNDERSTORMS AS THE GULF STORMS SPREAD
INLAND IN THE MORNING. HAVE RAISED POPS A LITTLE AND EXPANDED
INLAND. GUSTY WINDS AND HEAVY DOWNPOURS WILL ACCOMPANY THE STORMS
BUT NOT EXPECTING SEVERE WINDS BUT MAY HAVE SOME ISSUES WITH HEAVY
RAIN. MONDAY THE RIDGING FROM LA/GULF EXPANDS WEST AND DRIER AIR
EXPANDS OVERHEAD WITH LESS COVERAGE OF STORMS. RAIN CHANCES
GRADUALLY DECREASING MONDAY THROUGH FRIDAY WITH THE PATTERN
RETURNING TO MORE ISOLATED SHOWERS WITH AFTERNOON TEMPERATURES
REMAINING IN THE MID TO UPPER 90S. BY FRIDAY THE GUIDANCE IS
SHARPLY DIVERGING AND FOR NOW WILL FAVOR THE GFS AND ENSEMBLE
SOLUTIONS WITH UPPER RIDGING TAKING HOLD OVER THE AREA.
45
MARINE...
WINDS HAVE STARTED TO COME UP OVER THE WATERS THIS
MORNING THANKS TO THE SLIGHTLY TIGHTER PRESSURE GRADIENT. THE
WESTERN AREAS OF THE WATERS WILL APPROACH CAUTION CRITERIA SATURDAY
NIGHT INTO EARLY SUNDAY MORNING THANKS TO A WEAK SURFACE LOW IN WEST
TEXAS. THERE WILL ALSO BE A CHANCE OF ISOLATED TO SCATTERED SHOWERS
AND THUNDERSTORMS LATE NIGHT INTO EARLY MORNING EACH DAY. 23
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 98 77 97 77 96 / 10 10 20 10 10
HOUSTON (IAH) 96 77 94 77 95 / 20 10 30 10 20
GALVESTON (GLS) 92 83 90 82 90 / 20 20 40 10 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...45
AVIATION/MARINE...23
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
604 AM CDT SAT AUG 16 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 253 AM CDT SAT AUG 16 2014
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING OVER THE SOUTHWESTERN U.S....AN UPPER LOW IN NORTHERN
IDAHO...SHORTWAVES OVER THE DAKOTAS AND THE KANSAS CITY AREA...AND A
DEEP UPPER TROUGH OVER EASTERN CANADA INTO THE NORTHEAST U.S..
WITHIN THIS TROUGH...A FAIRLY POTENT SHORTWAVE WAS APPROACHING LAKE
SUPERIOR. THE FORECAST AREA LIES IN THE NORTHWEST FLOW ON THE
WESTERN EDGE OF THE TROUGH...BUT STILL NEAR THE INFLECTION POINT
FAVORING SUBSIDENCE AND HIGH PRESSURE AT THE SURFACE. THUS...ONLY
SOME SCATTERED CIRRUS CLOUDS HAVE BEEN TRACKING ACROSS THE FORECAST
AREA. 15.00Z MODELS DEFINITELY OVER-FORECAST THE PRECIPITABLE
WATER...INSTEAD OF BEING 1.5-1.75 INCHES IS ONLY 1-1.25 INCHES PER
GOES DERIVED IMAGERY. SURFACE DEWPOINTS ARE HIGHER...THOUGH...WHICH
WITH RADIATIONAL COOLING HAS LED TO SOME BR AND LOW STRATUS
DEVELOPMENT. THE NEAREST AREAS WHERE PRECIPITATION IS OCCURRING ARE
SOUTH OF I-80 IN IOWA ASSOCIATED WITH THE KANSAS CITY SHORTWAVE...
OVER THE CENTRAL DAKOTAS WITH THE SHORTWAVE THERE...AND THE MN
ARROWHEAD INTO UPPER MICHIGAN AHEAD OF THE APPROACHING SHORTWAVE.
THIS LAST PRECIPITATION AREA IS ALSO SUPPORTED BY A SURFACE COLD
FRONT TRACKING WITH IT.
500MB HEIGHTS ARE PROGGED TO RISE OVER THE NEXT 24 HOURS IN RESPONSE
TO THE UPPER LOW OVER NORTHERN ONTARIO PUSHING EAST INTO SOUTH
CENTRAL SASKATCHEWAN. TYPICALLY WHEN SEEING HEIGHT RISES ONE WOULD
EXPECT A WARM ADVECTION PATTERN. HOWEVER...IN THIS CASE...THE
SHORTWAVE APPROACHING LAKE SUPERIOR WILL DROP INTO THE EASTERN GREAT
LAKES THIS EVENING...SENDING ITS ASSOCIATED COLD FRONT THROUGH THE
FORECAST AREA.
MUCH OF THIS MORNING CONTINUES TO LOOK DRY AS ANY SHOWER ACTIVITY
ASSOCIATED WITH THE KANSAS CITY SHORTWAVE STAYS JUST TO THE
SOUTH...AS DEPICTED IN THE LATEST RAP/HRRR DATA. ANY FOG/STRATUS
SHOULD DISSIPATE WITHIN A FEW HOURS AFTER SUNRISE. HEADING INTO THE
AFTERNOON...DETERMINISTIC AND HIGH RESOLUTION MODELS REMAIN IN GOOD
AGREEMENT THAT THIS COLD FRONT WILL HELP INITIATE CONVECTION NORTH
OF I-94. THIS IS A RESULT TOO OF TEMPERATURES CLIMBING INTO THE 80S
FROM 850MB TEMPS AROUND 16C...AS WELL AS DEWPOINTS CLIMBING INTO THE
MID TO UPPER 60S...COMBINING TO PRODUCE MLCAPES OF 1000-2000 J/KG.
THIS CAPE IS OVERALL SKINNY AND 0-6 KM/0-3KM SHEAR ARE 20 KT OR LESS
WHICH WILL LIMIT SEVERE WEATHER POTENTIAL. HOWEVER...EQUILIBRIUM
LEVELS ARE NEAR 40000 FT AND WARM CLOUD DEPTHS APPROACH 4000
METERS...SO THE STORMS ARE LIKELY TO PRODUCE HEAVY RAIN. THE AMOUNT
OF CONVECTION SEEMS SCATTERED AT BEST SINCE THE BETTER FRONTAL
CONVERGENCE AND DYNAMIC FORCING ARE FARTHER EAST...MORE TOWARDS
LOWER MICHIGAN CLOSER TO THE SHORTWAVE TRACK.
CONVECTION NORTH OF I-94 IN THE AFTERNOON THEN LOOKS TO DROP SOUTH
IN THE EVENING WITH THE COLD FRONT. HOWEVER...COOLING TEMPERATURES
FROM LOSS OF DAYTIME HEATING AND THE FACT LITTLE CONVERGENCE EXISTS
ON THE FRONT WILL LIKELY RESULT IN A DIMINISHING TREND TO THE
CONVECTION. THERE MAY NOT BE MUCH LEFT AFTER 06Z AS THE 16.00Z GFS
SUGGESTS. IN THE WAKE OF THE COLD FRONT...IT APPEARS A LOW STRATUS
DECK MAY END UP DEVELOPING AND ADVECTING SOUTHWESTWARD. BASED ON
FORECAST SOUNDINGS...LOCATIONS SOUTHWEST OF I-94 APPEAR TO HAVE THE
GREATEST CHANCE OF SEEING THIS STRATUS DECK. COOLING 925MB TEMPS ON
THE EASTERLY FLOW SHOULD RESULT IN A COOLER NIGHT...ESPECIALLY IN
CENTRAL WI.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 253 AM CDT SAT AUG 16 2014
MAIN ISSUE ON SUNDAY RELATES TO THE SHORTWAVE OVER THE DAKOTAS
CURRENTLY. THE 16.00Z GFS/NAM TRACK THIS SHORTWAVE ACROSS MN DURING
THE DAY...WHICH HELPS PRODUCE SOME SHOWERS AND EMBEDDED STORMS
MOSTLY JUST WEST OF THE FORECAST AREA. PART OF THE REASON THIS
PRECIPITATION DOESNT DEVELOP FARTHER EAST IS A DRY EASTERLY FLOW
PROVIDED BY HIGH PRESSURE BUILDING OVER UPPER MI IN THE WAKE OF
TONIGHTS COLD FRONT. ITS POSSIBLE SOME OF THE SHOWER ACTIVITY
CREEPS INTO SOUTHEAST MN...BUT CONFIDENCE IS NOT HIGH ENOUGH TO PUT
ANY CHANCES IN YET. OTHERWISE...SUNDAY LOOKS COOLER THAN TODAY DUE
TO THE EASTERLY FLOW...MORNING STRATUS AND 925MB TEMPS ABOUT 4C
COOLER.
SUNDAY NIGHT NOW POSES SOME FORECAST CHALLENGE. 16.00Z ECMWF IS
SLOWER THAN THE GFS/NAM TRACKING THE SHORTWAVE EASTWARD OUT OF
MN...AND IN FACT HAS THE WAVE MOVE RIGHT ACROSS THE FORECAST AREA.
ADDITIONALLY...IN THE ECMWF...A SURGE OF 850MB MOISTURE TRANSPORT
ACCOMPANIES THE WAVE...HELPING TO PRODUCE SHOWERS AND STORMS ACROSS
MUCH OF THE AREA AND ESPECIALLY AFTER 06Z. NOW...THE 16.00Z GFS ALSO
DEPICTS AN INCREASE OF 850MB MOISTURE TRANSPORT AND PRECIPITATION...
BUT ITS MORE OVER NORTHWEST SECTIONS OF THE ARE AND IN RESPONSE TO
UPPER TROUGHING COMING INTO THE DAKOTAS. IN ANY EVENT...GIVEN THAT
THESE 2 MODELS ARE PRODUCING PRECIPITATION...FELT A NEED TO INCLUDE
20 PERCENT CHANCES IN FOR AT LEAST THE WEST HALF OF THE FORECAST
AREA. THESE MAY NEED TO BE INCREASED IF MODEL TRENDS CONTINUE.
MONDAY THROUGH TUESDAY...AND IN PARTICULARLY MONDAY NIGHT...STILL
REMAIN THE BEST CHANCE FOR WIDESPREAD RAIN. ALL MODELS ARE IN
AGREEMENT THAT THE CURRENT UPPER LOW OVER NORTHERN IDAHO...AND
ASSOCIATED GENERAL UPPER TROUGHING...WILL MOVE THROUGH THE FORECAST
AREA DURING THIS TIMEFRAME. A SURGE OF 1.5 INCH PRECIPITABLE WATER
COMBINED WITH DPVA FORCING FROM THE TROUGH...AS WELL AS INSTABILITY
SHOULD RESULT IN SHOWERS AND STORMS. MONDAY NIGHT SEEMS TO BE THE
BEST JUXTAPOSITION OF THE AFOREMENTIONED PARAMETERS AND THUS HIGHEST
CHANCES AROUND 70 PERCENT ARE CENTERED THERE. 0-6KM/0-3KM SHEAR
PROGGED LESS THAN 20 KT SO BRIEF HEAVY RAIN WOULD LIKELY BE THE MAIN
CONCERN WITH THE STORMS.
THE REST OF NEXT WEEK FEATURES THE UPPER LOW AND TROUGHING LIFTING
OUT OF THE REGION ON WEDNESDAY...FOLLOWED BY RIDGING BUILDING UP
ACROSS THE PLAINS AS TROUGHING REFORMS OVER THE PACIFIC NORTHWEST.
THIS SETUP IS FAVORABLE FOR BOTH WARM AND MOIST AIR ADVECTION...AND
AS SUCH MODELS CONTINUE TO OSCILLATE ON WHERE AND WHEN STORMS COULD
FIRE ON THE NOSE OF THIS ADVECTION. THEREFORE...FORECAST DEPICTS A
CONSENSUS WITH 20-40 PERCENT CHANCES FROM WEDNESDAY THROUGH FRIDAY.
THERE ARE SOME INDICATIONS WEDNESDAY COULD PAN OUT DRY...THUS LOWEST
CHANCES ARE CENTERED THEN. SEVERE WEATHER POTENTIAL WISE...IF THE
ECMWF PANS OUT...THERE COULD BE A SHOT FOR SOME ON THURSDAY. PLENTY
OF UNCERTAINTY OUT THERE...THOUGH. TEMPERATURES LOOK TO GRADUALLY
INCREASE EACH DAY WITH MOST DAYS AT OR ABOVE NORMAL. IT SHOULD BE
NOTED THAT IF ANY DAY ENDS UP WITH LESS CLOUDS...TEMPERATURES COULD
END UP WARMER THAN FORECAST.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 604 AM CDT SAT AUG 16 2014
LOW STRATUS AND FOG WILL IMPACT THE TAF SITES THROUGH 15Z THIS
MORNING WITH IFR/LIFR CONDITIONS EXPECTED. PLAN ON CEILINGS OF
800 FT AT KLSE. CEILINGS WILL BE LOWER AT TIMES AT KRST...FALLING
TO AROUND 500 FT. ALSO...VISIBILITY COULD BE REDUCED TO AROUND 2
SM AT KRST. THE FOG AND STRATUS WILL DISSIPATE AROUND 15Z AS
MIXING INCREASES WITH DAYTIME HEATING. A COLD FRONT IS EXPECTED TO
DROP SOUTH OUT OF NORTHERN WISCONSIN THIS AFTERNOON AND WILL HEAD
FOR THE TAF SITES THIS EVENING. SHOWERS AND THUNDERSTORMS ARE
POSSIBLE ALONG THE FRONT BUT LOOK TO STAY NORTH OF THE TAF SITES.
WILL HAVE TO KEEP A CLOSE EYE ON KLSE WHERE AN ISOLATED SHOWERS OR
THUNDERSTORM COULD OCCUR EARLY IN THE EVENING BEFORE INSTABILITY
WANES. MVFR/IFR CONDITIONS ARE EXPECTED LATE TONIGHT INTO SUNDAY
MORNING AS A STRATUS DECK MOVES INTO THE TAF SITES. KRST MAY SEE
SOME DENSE FOG AS WELL...MAINLY AFTER 08Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS PUEBLO CO
255 PM MDT SAT AUG 16 2014
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 236 PM MDT SAT AUG 16 2014
AN UPR RIDGE WL REMAIN CENTERED OVR NORTHERN AZ TONIGHT AND
SUNDAY. THIS AFTERNOON...WV SATELLITE IMAGERY SHOWING DRIER AIR
PUSHING EASTWARD ACRS THE STATE. HOWEVER THERE IS STILL ENOUGH
MSTR OUT THERE...THAT WITH THE AFTERNOON INSTABILITY...ISOLATED
SHOWERS/TSTMS HAVE DEVELOPED OVR THE SERN PLAINS WHERE THE MSTR IS
A LITTLE BETTER...AND ISOLATED TO SCATTERED CONVECTION HAS
DEVELOPED OVR THE MTNS. WILL KEEP ISOLD TO SCT SHOWERS/TSTMS IN
THE FORECAST ACRS THE AREA THRU THE EVENING HOURS...THEN SHOULD
SEE DECREASING PCPN CHANCES AFTER SUNSET. THE RAP AND HRRR SHOW
ALL PCPN ENDING BY MIDNIGHT. THE NAM KEEPS SOME PCPN GOING ACRS
MAINLY THE SEN PLAINS INTO THE LATE NIGHT. FOR NOW HAVE DECIDED TO
GO WITH RAP AND HRRR AND END ALL PCPN BY MIDNIGHT IN THE FORECAST.
THE NAM SHOWS SLIGHTLY LOWER PRECIPITABLE WATER VALUES ACRS THE
FORECAST AREA ON SUN...BUT THERE WL STILL BE ENOUGH MSTR AND
INSTABILITY FOR SHOWERS AND TSTMS TO DEVELOP. IT SHOULD START OVR
THE MTNS IN THE LATE MORNING/EARLY AFTERNOON HOURS WITH ISOLD TO SCT
COVERAGE IN THE AFTERNOON AND EVENING HOURS. SOME ISOLATED
SHOWERS/STORMS SHOULD DEVELOP OVR THE SERN PLAINS IN THE AFTERNOON
AS WELL. HIGH TEMPS ON SUN WL AGAIN BE A LITTLE ABOVE AVERAGE.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 236 PM MDT SAT AUG 16 2014
...MONSOON CONTINUES THROUGH NEXT WEEK...
THE TYPICAL SUMMER MONSOON WE HAVE BEEN DEALING WITH LOOKS
TO CONTINUE THROUGH NEXT WEEK. THE UPPER HIGH TO OUR SW WILL
SHIFT INTO ERN OK/TX AS A TROUGH OVER THE PACNW ADVANCES
EWD...AND THIS WILL KEEP A STEADY STREAM OF SUBTROPICAL
MOISTURE OVER OUR AREA.
SUN NIGHT...MODELS HAVE BEEN VERY CONSISTENT IN DEVELOPING
A LINE/CLUSTER OF STORMS OVER E-CENTRAL CO BY EARLY EVENING
IN A WEAK BAROCLINIC ZONE. THIS MCS WILL SHIFT SLOWLY SWD
DURING THE EVENING. EXPECT THE HEAVIEST QPF TO BE OVER ERN
AL PASO AND KIOWA COUNTIES. SHOULD CLEAR OUT AFTER MIDNIGHT.
MONDAY...WEAK UPSLOPE WILL PROVIDE AN EXTRA TRIGGER FOR MORE
PM STORMS...PROBABLY A BIT MORE COVERAGE OVER THE PLAINS THAN ON
PRECEDING DAYS. IT WILL BE ANOTHER VERY WARM DAY WITH SOME
MID 90S OVER THE HOT SPOTS ON THE PLAINS.
BY TUESDAY...WILL START TO SEE INCREASING MOISTURE MOVE NWD OVER
WRN CO AS A CUTTOFF DROPS ACROSS THE SRN CA COAST AND THE PACNW
TROUGH BEGINS MOVING INLAND. STILL SOME UNCERTAINTY ON HOW WELL
THE CUTOFF WILL PHASE WITH THE NRN JET BRANCH...AND THIS WILL
AFFECT HOW MUCH RAIN TO EXPECT OVER OUR AREA NEXT WEEK INTO NEXT
WEEKEND. HOWEVER...IT APPEARS LIKELY THAT THERE WILL BE
INCREASING SRLY FLOW AHEAD OF THE PACNW TROUGH...WHICH WILL LEAD
TO INCREASING HEAVY RAIN CONCERNS FOR THE CENTRAL MTS/CONTDVD TUE-
WED...AND THEN THE ERN RANGES AND POSSIBLY PLAINS BY LATE IN THE
WEEK. IF THE CUTOFF GETS PICKED UP SOONER BY THE ADVANCING
TROUGH...WE COULD SEE ENHANCED PRECIP OVER OUR WHOLE CWA. THE
LATEST 12Z ECMWF IS MUCH MORE AGGRESSIVE WITH PHASING THE LOW AND
PACNW TROUGH...AND WOULD BRING SIGNIFICANT PRECIP TO OUR AREA FOR
THE LATTER PART OF THE WEEK. FOR NOW...WILL STAY THE COURSE WITH
CONSERVATIVE LOW POPS FOR THE PLAINS AND TYPICAL SCT/CHANCE POPS
FOR THE MTS. WILL HAVE TO SEE HOW THINGS GO OVER THE NEXT COUPLE
OF DAYS...BUT IT BEARS WATCHING FOR THE POTENTIAL OF MORE
FLOODING...PARTICULARLY FOR THE MTS. ROSE
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 236 PM MDT SAT AUG 16 2014
VFR CONDITIONS ARE EXPECTED AT KCOS...KPUB AND KALS TONIGHT THROUGH
SUNDAY AFTERNOON. IT IS POSSIBLE THAT TSTMS COULD MOVE INTO THE
VCNTY OF THE TERMINAL SITES THIS EVENING...AND AGAIN BY MID TO LATE
AFTERNOON ON SUNDAY.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...28
LONG TERM...ROSE
AVIATION...28
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1120 AM MDT SAT AUG 16 2014
.UPDATE...
ISSUED AT 1108 AM MDT SAT AUG 16 2014
FIRST STORMS OF THE DAY FIRING ALONG THE ABAJO MOUNTAINS IN
SOUTHEAST UTAH AND ACROSS THE SOUTHERN EXTENT OF THE UNCOMPAHGRE
PLATEAU NEAR DALLAS DIVIDE. THIS ACTIVITY IS EXPECTED TO CONTINUE
THROUGH THIS AFTERNOON AND INTO THE EARLY EVENING HOURS. NO
SIGNIFICANT WAVES AND SHEAR PROFILES REMAIN WEAK...SO STORMS
EXPECTED TO BE SHORT-LIVED AND CONFINED TO THE HIGHER TERRAIN.
EXCEPTION WILL BE ACROSS THE SOUTHERN VALLEYS SOUTH OF THE SAN
JUANS WITH LATEST HRRR RUN SUGGESTIONS A FEW STRONGER STORMS
DRIFTING SOUTH OFF THE SAN JUANS BETWEEN 2 AND 5 PM THIS
AFTERNOON. THIS MAY IMPACT THE DURANGO AND PAGOSA SPRINGS AREAS
WITH GUSTY WINDS...SMALL HAIL AND BRIEF HEAVY RAIN.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 340 AM MDT SAT AUG 16 2014
WATER VAPOR SHOWS DRIER AIR ALOFT ADVECTING ACROSS UTAH AND WRN
COLORADO...BUT ALSO EVIDENT IS AN EMBEDDED DISTURBANCE THAT
MANAGED TO KEEP PERSISTENT NOCTURNAL THUNDERSTORMS IN THE
VICINITY OF KCNY...ARCHES NP...AND MOAB FOR A FEW HOURS. HIGH
PRESSURE OVER UTAH AND WRN COLORADO AND ITS DRIER AIR MASS WILL
BE THE DOMINANT FEATURE TODAY. HOWEVER LOWER LEVEL MOISTURE
(SURFACE DEW POINTS REMAIN AROUND 50F) AND STEEP AFTERNOON LAPSE
RATES WILL TRIGGER SOME AFTERNOON CONVECTION. THE AIR MASS IS
DRIER TODAY AS PRECIPITABLE WATER VALUES HAVE DROPPED TO THREE
QUARTERS OF AN INCH (PER KGJT SOUNDING). AREAL COVERAGE OF STORMS
WILL BE LESS NUMEROUS THAN FRIDAY AFTERNOON. NO DISTURBANCE IS
EVIDENT IN THE MODEL DATA...SO STRONG SURFACE HEATING WILL BE THE
PRIMARY TRIGGER MECHANISM.
A DISTURBANCE PASSES THROUGH THE CANADIAN ROCKIES TONIGHT
FLATTENING THE RIDGE. A VERY WEAK ASSOCIATED WAVE PASSES ALONG THE
CO-WY BORDER...BUT MOISTURE LOOKS VERY LIMITED. SO NOCTURNAL
STORMS ARE NOT EXPECTED.
SUNDAY...PRECIPITABLE WATER VALUES ARE AROUND 0.6 INCH WHICH IS
LOW FOR MID AUGUST. ISOLATED AFTERNOON STORMS ARE POSSIBLE OVER
ALL MOUNTAINS WITH LITTLE RAINFALL CHANCE IN THE VALLEYS. STORM
MOTION WILL BE TO THE EAST AT AROUND 15 KTS. AFTERNOON
TEMPERATURES WILL BE A FEW DEGREES ABOVE NORMAL.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 340 AM MDT SAT AUG 16 2014
LITTLE CHANGE IS EXPECTED SUNDAY NIGHT THROUGH MONDAY. THE BROAD
RIDGE IS CENTERED NEAR THE FOUR CORNERS WITH ONLY MARGINAL
RESIDUAL MOISTURE AVAILABLE FOR LATE-DAY STORMS. A TROUGH IS
DEVELOPING ALONG THE WEST COAST. MOISTURE BEGINS TO SURGE INTO SE
UTAH AS EARLY AS MONDAY AFTERNOON OR EVENING. THERE IS STILL SOME
UNCERTAINTY ON THE TIMING AND DEPTH OF THIS MOISTURE SURGE. BUT
THE GFS AND SREF PRODUCE PRECIPITABLE WATER VALUES OVER AN INCH IN
SE UTAH TOWARDS TUESDAY MORNING. HAVE ADDED ISOLATED LATE NIGHT
THUNDERSTORMS SPREADING NORTHWARD ALONG THE UT-CO STATELINE.
INCREASING CONFIDENCE THAT THE MONSOONAL MOISTURE TAP DEEPENS BY
TUESDAY AND WILL LAST INTO NEXT FRIDAY. THE GFS REMAINS THE MOST
AGGRESSIVE MODEL WITH A SIGNIFICANT LONG WAVE TROUGH ALONG THE
WEST COAST THAT STRENGTHENS THE SOUTHERLY COMPONENT. WITH
TIME...ENERGY EMBEDDED IN THE WESTERLIES ABSORBS THE CLOSED LOW
WITH SHORT WAVE ENERGY MOVING ACROSS THE GREAT BASIN TOWARD THE
CENTRAL ROCKIES. THE ECMWF MODEL SHOWS THE MID LEVEL CLOSED LOW
CIRCULATION ALONG THE CENTRAL CALIFORNIA COAST...ALLOWING FOR A
MONSOONAL MOISTURE INTO UTAH AND COLORADO. BUT THE ECMWF ALLOWS
THE CLOSED LOW TO RETROGRADE WESTWARD. SOME UNCERTAINTY ON HOW
THIS EVOLVES NEXT WEEK AND THIS WILL DICTATE THE STRENGTH OF THIS
MONSOONAL SURGE AND AREAL COVERAGE OF THUNDERSTORMS AND NOCTURNAL
STORM ACTIVITY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1108 AM MDT SAT AUG 16 2014
ISOLATED THUNDERSTORMS WILL CONTINUE ACROSS THE HIGHER TERRAIN
THROUGH 03Z THIS EVENING. A FEW STORMS WILL DRIFT SOUTH OFF THE
SAN JUAN MOUNTAINS...POSSIBLY IMPACTING KDRO AND KPSO. GUSTY WINDS
TO 45 MPH...SMALL HAIL AND BRIEF HEAVY RAINFALL WILL BE POSSIBLE
WITH ANY STORMS. KTEX...KDRO AND KPSO WILL SEE A 30 PERCENT CHANCE
OF THUNDERSTORMS THROUGH 03Z THIS EVENING...OTHERWISE...VFR
CONDITIONS CONTINUE.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
UPDATE...JDC
SHORT TERM...PF/JOE
LONG TERM...JOE/PF
AVIATION...JDC
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
136 PM EDT SAT AUG 16 2014
.SYNOPSIS...
WEAK HIGH PRESSURE WILL INFLUENCE THE MID ATLANTIC TODAY. A COLD
FRONT WILL APPROACH FROM THE GREAT LAKES TONIGHT BEFORE MOVING
THROUGH THE AREA SUNDAY. THE FRONT WILL STALL TO THE SOUTH OF THE
AREA MONDAY. A WAVE OF LOW PRESSURE WILL TRACK ALONG THE FRONTAL
BOUNDARY AND ACROSS THE MID-ATLANTIC REGION MONDAY NIGHT AND
TUESDAY. HIGH PRESSURE RETURNS WEDNESDAY. HIGH PRESSURE WILL BECOME
ESTABLISHED ACROSS THE SOUTHERN AND CENTRAL UNITED STATES LATE IN
THE WEEK WHILE A SERIES OF DISTURBANCES TRACK AROUND THE NORTHERN
PERIPHERY OF THE HIGH AND THROUGH OUR REGION.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WITH THE 12:30 AM UPDATE MAXIMUM TEMPERATURES WERE LOWERED
SLIGHTLY AS SOME HIGH CLOUDS HAS PREVENTED MAXIMUM HEATING TODAY.
DEWPOINTS HAVE ALSO BEEN LOWERED SOME ACROSS THE 1-95 CORRIDOR IN
LINE WITH THE RECENT METAR OBS. THINK THE RAP IS OVERDONE WITH
SHOWERS DOWN SOUTH FOR THIS AFTERNOON AND HAVE REMOVED THIS
PRECIPITATION CHANCE FROM THE FORECAST.
THE MAJORITY OF THE REGION WILL STAY RAIN FREE TODAY WITH THE
ONLY EXCEPTION BEING EXTREME SOUTHERN DELMARVA. A WEAK MID- LEVEL
IMPULSE MOVING THROUGH OUR SOUTH, ALONG AN OLD FRONTAL BOUNDARY,
TOUCHED OFF A FEW SHOWERS IN SOUTHERN MARYLAND THAT WILL DRIFT
OVER EXTREME SOUTHERN DELMARVA THIS MORNING. ACROSS MOST OF THE
REGION SOUTHWEST WINDS WILL ALLOW FOR BETTER THERMAL ADVECTION
UNDER MOSTLY SUNNY SKIES AS THERE IS PLENTY OF DRY ALOFT TO MIX
DOWN.
TEMPERATURES WERE A BLEND OF THE MET/MAV GUIDANCE WITH A HEAVIER
WEIGHING TOWARDS THE COOLER MET TODAY. THE NAM INITIALIZED BETTER AT
850 AND 925MB COMPARED TO THE MAV, HENCE THE SLIGHT EDGE TOWARDS THE
MET.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
A SLOW MOVING COLD FRONT APPROACHES FROM THE NORTHWEST LATE TONIGHT
INTO SUNDAY. CONTINUED AIRMASS MODIFICATION TONIGHT, WITH DEWPOINTS
RISING TOWARDS 60F, COULD PROVIDE ENOUGH MOISTURE FOR THE
APPROACHING FRONT TO TAP INTO. THE BETTER FORCING LOOKS TO REMAIN
OUR NORTHWEST ZONES LATE TONIGHT BUT A FEW STRAY SHOWERS COULD DRIFT
ACROSS OUR NORTHERN ZONES BY TOMORROW MORNING...WE KEEP THE CHANCE
POPS GOING. OVERNIGHT LOWS WILL BE A FEW DEGREES WARMER THAN THIS
MORNING WITH THE WARMER STARTING POINT AND INCREASING CLOUD COVER
EXPECTED.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
ON SUNDAY, THE MID-ATLANTIC REGION WILL BE POSITIONED TOWARD THE
BASE OF AN UPPER TROUGH THAT IS ASSOCIATED WITH A CLOSED LOW OVER
EASTERN CANADA. 00Z MODEL GUIDANCE IN REASONABLY GOOD AGREEMENT WITH
THE SFC COLD FRONT MOVING THRU THE ERN PA/NJ SUNDAY MORNING. MAY SEE
A LINGERING SHOWER IN THE PA MTS TO START THE DAY. FARTHER EAST,
REMOVED MENTION OF SHOWERS WITH THE BEST UPPER FORCING FROM THE
TROUGH MOVING AWAY FROM THE AREA AND LLVL DOWNSLOPING/WLY FLOW
HELPING TO SCOUR OUT MOISTURE. HOWEVER, SRN PORTION OF THE FRONT IS
FORECAST TO GET HUNG UP OVER NERN MD INTO THE DELMARVA UNDER WEAKER
STEERING FLOW ALOFT. MODELS GENERALLY SHOW DEWPOINTS IN THE MID 60S
TO NEAR 70F JUST SOUTH OF THE FRONT. THERE IS A CHANCE FOR AFTERNOON
SHOWERS AND STORMS TO DEVELOP IN THESE SOUTHERN ZONES IF THE TIMING
OF FROPA OCCURS LATE ENOUGH IN THE DAY TO COINCIDE WITH PEAK DIURNAL
HEATING.
SKIES WILL CLEAR FROM NORTH TO SOUTH BEHIND THE FRONT DURING THE
AFTERNOON. POST-FRONTAL AIRMASS OVER CENTRAL AND NORTHERN NJ AND
EASTERN PA WILL BE CHARACTERIZED BY NOTICEABLY DRIER AIR WITH
DEWPOINTS IN THE 50S.
THE COLD FRONT WILL STALL SOUTH OF THE AREA SUNDAY NIGHT INTO
MONDAY. ANY SHOWER ACTIVITY WITH THE FRONT WILL SUBSEQUENTLY SHIFT
SOUTH OF THE CWA. 00Z MODEL GUIDANCE COMING INTO SLIGHTLY BETTER
AGREEMENT WITH A WAVE OF LOPRES DEVELOPING OVER THE MIDWEST DURING
THIS TIME. THIS LOW IS THEN EXPECTED TO TRACK EASTWARD ALONG THE
STALLED BOUNDARY INTO THE MID-ATLANTIC REGION LATE MONDAY INTO
TUESDAY. THE PAST FEW RUNS OF THE ECMWF APPEARS TO BE SOUTHERN
OUTLIER WITH REGARDS TO THE TRACK OF THIS SYSTEM, KEEPING THE BULK
OF THE PRECIP SOUTH OF THE DELAWARE BAY WHILE MAJORITY OF OTHER 00Z
OPERATIONAL GUIDANCE EXHIBITS A MORE NORTHERN TRACK THAT GIVES A
PERIOD OF PRECIP TO JUST ABOUT THE ENTIRE AREA. HAVE CONFINED
MENTION OF THUNDER TO EXTREME SOUTHERN NJ ATTM, BUT TSTM CHANCES
WILL DEPEND ON HOW FAR NORTH WARM SECTOR ADVANCES.
THE LOW IS EXPECTED TO MOVE OFF THE MID-ATLANTIC COAST TUESDAY
AFTERNOON, ALLOWING FOR CLEARING SKIES FROM NORTHWEST TO SOUTHEAST
LATE IN THE DAY INTO TUESDAY NIGHT. DRY CONDITIONS EXPECTED
WEDNESDAY WITH WEAK HIPRES OVER THE AREA.
UPPER RIDGE BUILDS ACROSS THE SOUTHERN/CENTRAL CONUS TOWARD THE END
OF THE WEEK. THE MID-ATLANTIC REGION IS EXPECTED TO BE SITUATED TO
THE NORTHEAST OF THE RIDGE AT THE SAME TIME THAT THE UPPER TROUGH
LINGERS OVER THE NORTHEAST STATES. THE BELT OF STRONGER
WEST-NORTHWESTERLIES ALOFT WOULD BE FAVORED CLOSE TO THIS LATITUDE.
WOULD EXPECT A SOMEWHAT ACTIVE PATTERN WITH SEVERAL SHORTWAVE
DISTURBANCES TRACKING ACROSS THE AREA DURING THIS TIME. CHANCE POPS
ARE FORECAST FOR MOST OF THE CWA THURSDAY AND FRIDAY.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
VFR CONDITIONS CONTINUE TODAY WITH A WIND GUST OR TO NOT OUT OF THE
QUESTION OVER 15KT. GIVEN MOST LOCATIONS ARE UNLIKELY TO
EXPERIENCE STRONG WIND GUSTS TODAY, LEFT OUT OF TAFS. WE WILL SEE MID
AND LEVEL HIGH CLOUDS CONTINUE TO MOVE IN FROM THE NORTHWEST AHEAD
OF A COLD FRONT THROUGH TONIGHT. CLOUDS SHOULD MAINLY BE FROM
5-10,000 FEET UP WITH MOSTLY CLOUDY CONDITIONS IN THE MORNING AS
THE FRONT PASSES THROUGH. A SHOWER OR RUMBLE OF THUNDER CAN NOT BE
RULED OUT LATE TONIGHT AND SUNDAY. HOWEVER, COVERAGE LOOKS TO BE
ISOLATED AND LEFT PRECIPITATION OUT OF TAFS AT ALL SITES. A BETTER
CHANCE FOR WIND GUSTS IS PRESENT SUNDAY AFTERNOON AND PLACED GUSTS
INTO THE TAF FOR PHL TOMORROW WITH TIMING FOCUSED AFTER 18Z.
OUTLOOK...
SUNDAY NIGHT THROUGH MONDAY- VFR AND DRY.
MONDAY NIGHT THROUGH TUESDAY- SHRA MOVE INTO THE AREA. LOCAL
VSBY/CIG RESTRICTIONS POSSIBLE, ESPECIALLY IN SRN TERMINALS.
TUESDAY NIGHT THROUGH WEDNESDAY- VFR.
&&
.MARINE...
SUB-SCA CONDITIONS EXPECTED ACROSS OUR WATERS TODAY AND TONIGHT.
WINDS WILL INCREASE THIS AFTERNOON FROM THE SOUTH BETWEEN 10-15
KNOTS AND SEAS WILL SLOWLY BUILD UPWARDS OF 3 FEET THROUGH SUNDAY
MORNING. LOWERED WAVE HEIGHTS SLIGHTLY WITH THE 12:30 PM UPDATE
BASED ON BUOY OBS.
OUTLOOK...
A COLD FRONT WILL MOVE THRU THE WATERS SUNDAY. SWLY WINDS AHEAD
OF THE FRONT WILL SHIFT OUT OF THE W-NW IN WAKE OF FROPA. WINDS
BELOW SCA THRESHOLD. A WAVE OF LOPRES TRACKS NEAR THE DELAWARE
WATERS MONDAY NIGHT AND TUESDAY. WINDS STRENGTHEN TO 15-20 KT
NORTH OF THE LOW TRACK TUESDAY AND WEDNESDAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KLEIN
NEAR TERM...GAINES/HEAVENER
SHORT TERM...HEAVENER
LONG TERM...KLEIN
AVIATION...GAINES/HEAVENER/KLEIN
MARINE...GAINES/HEAVENER/KLEIN
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1227 PM EDT SAT AUG 16 2014
.SYNOPSIS...
WEAK HIGH PRESSURE WILL INFLUENCE THE MID ATLANTIC TODAY. A COLD
FRONT WILL APPROACH FROM THE GREAT LAKES TONIGHT BEFORE MOVING
THROUGH THE AREA SUNDAY. THE FRONT WILL STALL TO THE SOUTH OF THE
AREA MONDAY. A WAVE OF LOW PRESSURE WILL TRACK ALONG THE FRONTAL
BOUNDARY AND ACROSS THE MID-ATLANTIC REGION MONDAY NIGHT AND
TUESDAY. HIGH PRESSURE RETURNS WEDNESDAY. HIGH PRESSURE WILL BECOME
ESTABLISHED ACROSS THE SOUTHERN AND CENTRAL UNITED STATES LATE IN
THE WEEK WHILE A SERIES OF DISTURBANCES TRACK AROUND THE NORTHERN
PERIPHERY OF THE HIGH AND THROUGH OUR REGION.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WITH THE 12:30 AM UPDATE MAXIMUM TEMPERATURES WERE LOWERED
SLIGHTLY AS SOME HIGH CLOUDS HAS PREVENTED MAXIMUM HEATING TODAY.
DEWPOINTS HAVE ALSO BEEN LOWERED SOME ACROSS THE 1-95 CORRIDOR IN
LINE WITH THE RECENT METAR OBS. THINK THE RAP IS OVERDONE WITH
SHOWERS DOWN SOUTH FOR THIS AFTERNOON AND HAVE REMOVED THIS
PRECIPITATION CHANCE FROM THE FORECAST.
THE MAJORITY OF THE REGION WILL STAY RAIN FREE TODAY WITH THE
ONLY EXCEPTION BEING EXTREME SOUTHERN DELMARVA. A WEAK MID- LEVEL
IMPULSE MOVING THROUGH OUR SOUTH, ALONG AN OLD FRONTAL BOUNDARY,
TOUCHED OFF A FEW SHOWERS IN SOUTHERN MARYLAND THAT WILL DRIFT
OVER EXTREME SOUTHERN DELMARVA THIS MORNING. ACROSS MOST OF THE
REGION SOUTHWEST WINDS WILL ALLOW FOR BETTER THERMAL ADVECTION
UNDER MOSTLY SUNNY SKIES AS THERE IS PLENTY OF DRY ALOFT TO MIX
DOWN.
TEMPERATURES WERE A BLEND OF THE MET/MAV GUIDANCE WITH A HEAVIER
WEIGHING TOWARDS THE COOLER MET TODAY. THE NAM INITIALIZED BETTER AT
850 AND 925MB COMPARED TO THE MAV, HENCE THE SLIGHT EDGE TOWARDS THE
MET.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
A SLOW MOVING COLD FRONT APPROACHES FROM THE NORTHWEST LATE TONIGHT
INTO SUNDAY. CONTINUED AIRMASS MODIFICATION TONIGHT, WITH DEWPOINTS
RISING TOWARDS 60F, COULD PROVIDE ENOUGH MOISTURE FOR THE
APPROACHING FRONT TO TAP INTO. THE BETTER FORCING LOOKS TO REMAIN
OUR NORTHWEST ZONES LATE TONIGHT BUT A FEW STRAY SHOWERS COULD DRIFT
ACROSS OUR NORTHERN ZONES BY TOMORROW MORNING...WE KEEP THE CHANCE
POPS GOING. OVERNIGHT LOWS WILL BE A FEW DEGREES WARMER THAN THIS
MORNING WITH THE WARMER STARTING POINT AND INCREASING CLOUD COVER
EXPECTED.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
ON SUNDAY, THE MID-ATLANTIC REGION WILL BE POSITIONED TOWARD THE
BASE OF AN UPPER TROUGH THAT IS ASSOCIATED WITH A CLOSED LOW OVER
EASTERN CANADA. 00Z MODEL GUIDANCE IN REASONABLY GOOD AGREEMENT WITH
THE SFC COLD FRONT MOVING THRU THE ERN PA/NJ SUNDAY MORNING. MAY SEE
A LINGERING SHOWER IN THE PA MTS TO START THE DAY. FARTHER EAST,
REMOVED MENTION OF SHOWERS WITH THE BEST UPPER FORCING FROM THE
TROUGH MOVING AWAY FROM THE AREA AND LLVL DOWNSLOPING/WLY FLOW
HELPING TO SCOUR OUT MOISTURE. HOWEVER, SRN PORTION OF THE FRONT IS
FORECAST TO GET HUNG UP OVER NERN MD INTO THE DELMARVA UNDER WEAKER
STEERING FLOW ALOFT. MODELS GENERALLY SHOW DEWPOINTS IN THE MID 60S
TO NEAR 70F JUST SOUTH OF THE FRONT. THERE IS A CHANCE FOR AFTERNOON
SHOWERS AND STORMS TO DEVELOP IN THESE SOUTHERN ZONES IF THE TIMING
OF FROPA OCCURS LATE ENOUGH IN THE DAY TO COINCIDE WITH PEAK DIURNAL
HEATING.
SKIES WILL CLEAR FROM NORTH TO SOUTH BEHIND THE FRONT DURING THE
AFTERNOON. POST-FRONTAL AIRMASS OVER CENTRAL AND NORTHERN NJ AND
EASTERN PA WILL BE CHARACTERIZED BY NOTICEABLY DRIER AIR WITH
DEWPOINTS IN THE 50S.
THE COLD FRONT WILL STALL SOUTH OF THE AREA SUNDAY NIGHT INTO
MONDAY. ANY SHOWER ACTIVITY WITH THE FRONT WILL SUBSEQUENTLY SHIFT
SOUTH OF THE CWA. 00Z MODEL GUIDANCE COMING INTO SLIGHTLY BETTER
AGREEMENT WITH A WAVE OF LOPRES DEVELOPING OVER THE MIDWEST DURING
THIS TIME. THIS LOW IS THEN EXPECTED TO TRACK EASTWARD ALONG THE
STALLED BOUNDARY INTO THE MID-ATLANTIC REGION LATE MONDAY INTO
TUESDAY. THE PAST FEW RUNS OF THE ECMWF APPEARS TO BE SOUTHERN
OUTLIER WITH REGARDS TO THE TRACK OF THIS SYSTEM, KEEPING THE BULK
OF THE PRECIP SOUTH OF THE DELAWARE BAY WHILE MAJORITY OF OTHER 00Z
OPERATIONAL GUIDANCE EXHIBITS A MORE NORTHERN TRACK THAT GIVES A
PERIOD OF PRECIP TO JUST ABOUT THE ENTIRE AREA. HAVE CONFINED
MENTION OF THUNDER TO EXTREME SOUTHERN NJ ATTM, BUT TSTM CHANCES
WILL DEPEND ON HOW FAR NORTH WARM SECTOR ADVANCES.
THE LOW IS EXPECTED TO MOVE OFF THE MID-ATLANTIC COAST TUESDAY
AFTERNOON, ALLOWING FOR CLEARING SKIES FROM NORTHWEST TO SOUTHEAST
LATE IN THE DAY INTO TUESDAY NIGHT. DRY CONDITIONS EXPECTED
WEDNESDAY WITH WEAK HIPRES OVER THE AREA.
UPPER RIDGE BUILDS ACROSS THE SOUTHERN/CENTRAL CONUS TOWARD THE END
OF THE WEEK. THE MID-ATLANTIC REGION IS EXPECTED TO BE SITUATED TO
THE NORTHEAST OF THE RIDGE AT THE SAME TIME THAT THE UPPER TROUGH
LINGERS OVER THE NORTHEAST STATES. THE BELT OF STRONGER
WEST-NORTHWESTERLIES ALOFT WOULD BE FAVORED CLOSE TO THIS LATITUDE.
WOULD EXPECT A SOMEWHAT ACTIVE PATTERN WITH SEVERAL SHORTWAVE
DISTURBANCES TRACKING ACROSS THE AREA DURING THIS TIME. CHANCE POPS
ARE FORECAST FOR MOST OF THE CWA THURSDAY AND FRIDAY.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
TODAY...VFR. LIGHT AND VARIABLE WINDS TO START BECOMING
SOUTHWESTERLY 8-10 KNOTS. AFTERNOON STRATOCU DECK AROUND 4-5KFT.
TONIGHT...VFR. WINDS DECREASE AND REMAIN OUT OF THE SOUTHWEST. A FEW
SPOTTY SHOWERS ARE POSSIBLE NEAR RDG/ABE LATE TONIGHT. CONFIDENCE
LOW ON LOCATION SO LEFT OUT THEIR MENTION IN THE TAFS.
OUTLOOK...
SUNDAY- SLIGHT CHANCE OF A SHRA NEAR RDG/ABE IN THE MRNG. CHANCE
OF TSRA AS FAR NORTH OF AS ILG IN THE AFTN. MAINLY A VFR DAY.
SUNDAY NIGHT THROUGH MONDAY- VFR AND DRY.
MONDAY NIGHT THROUGH TUESDAY- SHRA MOVE INTO THE AREA. LOCAL
VSBY/CIG RESTRICTIONS POSSIBLE, ESPECIALLY IN SRN TERMINALS.
TUESDAY NIGHT THROUGH WEDNESDAY- VFR.
&&
.MARINE...
SUB-SCA CONDITIONS EXPECTED ACROSS OUR WATERS TODAY AND TONIGHT.
WINDS WILL INCREASE THIS AFTERNOON FROM THE SOUTH BETWEEN 10-15
KNOTS AND SEAS WILL SLOWLY BUILD UPWARDS OF 3 FEET THROUGH SUNDAY
MORNING. LOWERED WAVE HEIGHTS SLIGHTLY WITH THE 12:30 PM UPDATE
BASED ON BUOY OBS.
OUTLOOK...
A COLD FRONT WILL MOVE THRU THE WATERS SUNDAY. SWLY WINDS AHEAD
OF THE FRONT WILL SHIFT OUT OF THE W-NW IN WAKE OF FROPA. WINDS
BELOW SCA THRESHOLD. A WAVE OF LOPRES TRACKS NEAR THE DELAWARE
WATERS MONDAY NIGHT AND TUESDAY. WINDS STRENGTHEN TO 15-20 KT
NORTH OF THE LOW TRACK TUESDAY AND WEDNESDAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KLEIN
NEAR TERM...GAINES/HEAVENER
SHORT TERM...HEAVENER
LONG TERM...KLEIN
AVIATION...HEAVENER/KLEIN
MARINE...GAINES/HEAVENER/KLEIN
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
402 PM EDT SAT AUG 16 2014
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL REMAIN CENTERED SOUTH AND EAST OF THE
REGION THROUGH NEXT WEEK...WHILE A WEAK TROUGH OF LOW PRESSURE
PERSISTS INLAND. A COLD FRONT MAY APPROACH THE REGION LATE NEXT
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
REST OF THE AFTERNOON...SO FAR CONVECTION HAS BEEN ISOLATED IN
COVERAGE AND VERY WEAK...MAINLY CONFINED TO EASTERN CHARLESTON
COUNTY AROUND AWENDAW AND MCCLELLANVILLE. I HAVE MAINTAINED THE
CURRENT POP SCHEME AS RECENT RUNS OF THE RAP AND HRRR SHOW COVERAGE
INCREASING OVER THE NEXT COUPLE OF HOURS. THE THREAT FOR A COUPLE OF
STRONG TO SEVERE STORMS REMAINS AS DCAPES ARE GREATER THAN 1000 J/KG
THANKS TO MID LEVEL DRY AIR. DAMAGING WIND GUSTS AND LIGHTNING
REMAIN THE BIGGEST THREATS FROM ANY THUNDERSTORMS THAT DEVELOP.
TONIGHT...ANY LINGERING CONVECTION SHOULD DIMINISH QUICKLY WITH THE
LOSS OF HEATING THIS EVENING. UNLIKE PREVIOUS NIGHTS...MODELS SHOW
NO NOCTURNAL CONVECTION AND THE FORECAST IS DRY FOR THE OVERNIGHT.
THE PRESSURE GRADIENT WILL TIGHTEN A BIT OVERNIGHT AS WELL WHICH
WILL HELP MAINTAIN A LIGHT SOUTHWEST FLOW. SKIES WILL CLEAR OFF
THROUGH THE NIGHT AND MOST AREAS WILL BE MOSTLY CLEAR. LOWS WILL
RANGE FROM AROUND 70 INLAND TO THE MID/UPPER 70S ALONG THE COAST.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
ZONAL UPPER LEVEL FLOW WILL PERSIST THROUGH THE PERIOD. AT THE
SURFACE...ATLANTIC HIGH PRESSURE WILL REMAIN SOUTH AND EAST OF THE
REGION. THIS OVERALL PATTERN WILL RESULT IN DEEP WESTERLY FLOW AND
HOT TEMPERATURES...AT LEAST 3 TO 5 DEGS ABOVE NORMAL EACH DAY.
SUNDAY...THIS WILL BE THE DAY WITH THE LOWEST COVERAGE OF
CONVECTION...WITH PWS GENERALLY LESS THAN 1.5 INCHES AND MEAN RH
VALUES LESS THAN 50%. HAVE MAINTAINED SLIGHT CHANCE POPS FOR
AFTERNOON CONVECTION ALONG THE SEA BREEZE...WHICH SHOULD REMAIN OVER
THE EASTERN 1/3 OF THE AREA DUE TO BACKGROUND WEST-SOUTHWEST FLOW.
HIGH TEMPERATURES IN THE MID 90S. HEAT INDICES EXPECTED TO HOLD
AROUND 100 WITH SURFACE TDS EXPECTED TO MIX DOWN TO THE UPPER 60S TO
LOWER 70S BY AFTERNOON. ANY CONVECTION WILL DIE DOWN AFTER SUNSET
WITH LOWS IN THE MID 70S MOST AREAS.
MONDAY AND TUESDAY...HIGHER VALUES OF DEEP LAYER MOISTURE RETURNS IN
THE PERIOD WITH PWS AROUND 2 INCHES. LOW LEVEL FLOW WILL CONTINUE TO BE
WEST-SOUTHWEST...KEEPING ANY AFTERNOON SEA BREEZE PINNED WITH 10-15
MILES OF THE COAST. HAVE KEPT LOW END CHANCE POPS BOTH AFTERNOONS.
GLOBAL MODELS BOTH SHOW A WELL DEFINED ELONGATED UPPER VORTICITY
LOBE MOVING ACROSS THE AREA TUESDAY... WHICH MAY HELP TO INCREASE
COVERAGE MORE THAN MONDAY. IF THIS VORT LOBE CONTINUES TO BE SHOWN
BY THE MODELS ON TUESDAY...MAY NEED TO NUDGE POPS UP. HIGH
TEMPERATURES WILL CONTINUE HOT...IN THE MID TO POSSIBLY UPPER 90S.
AFTERNOON SURFACE TDS EXPECTED TO BE IN THE LOWER 70S...KEEPING HEAT
INDICES 103-106...BELOW HEAT ADVISORY CRITERIA. BOTH NIGHTS WILL
CONTINUE VERY WARM...IN THE MID TO UPPER 70S.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
A BROAD UPPER RIDGE WILL REMAIN IN PLACE TUESDAY NIGHT THROUGH
THURSDAY BEFORE RETROGRADING IN RESPONSE TO A DIGGING UPPER TROUGH
OVER THE MID-ATLANTIC REGION. WEDNESDAY AND THURSDAY WILL BE WARM
WITH HIGHS IN THE MIDDLE 90S. RAIN CHANCES LOOK LOW GIVEN THE MID
LEVEL CAPPING AND RATHER WEAK SEA BREEZE SO WE ARE ONLY CARRYING A
SLIGHT CHANCE POP. FRIDAY INTO SATURDAY ARE LESS CERTAIN DUE TO THE
POTENTIAL FOR A COLD FRONT TO DROP INTO THE AREA. MODELS ARE SPLIT
ON THE STRENGTH OF THE FRONT...THOUGH AT THIS POINT WE HAVE LOW END
POPS AND SLIGHTLY COOLER TEMPS.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
THE BIGGEST NEAR TERM FORECAST ISSUE IS THE POTENTIAL FOR
THUNDERSTORMS AT THE TERMINALS. THE BEST CHANCE APPEARS TO BE AT
KCHS AS THE SEA BREEZE PUSHES INLAND. HAVE ADDED A VCTS STARTING
AT 1930Z AND THEN A TEMPO FOR MVFR TS CONDITIONS BETWEEN 20Z-22Z.
OTHERWISE TAF/S ARE VFR. SOME LOW END POTENTIAL FOR LIGHT FOG
TONIGHT...BUT CONFIDENCE TOO LOW TO INCLUDE IN THE FORECAST.
EXTENDED AVIATION OUTLOOK...SUNDAY...MAINLY VFR. MONDAY-
FRIDAY...MORE TYPICAL SCATTERED AFTERNOON SHOWERS AND THUNDERSTORMS
EXPECTED...WITH VERY BRIEF PERIODS OF FLIGHT RESTRICTIONS POSSIBLE.
&&
.MARINE...
TONIGHT...THE PRESSURE GRADIENT WILL TIGHTEN UP A BIT OVERNIGHT WITH
A SURFACE TROUGH INLAND. THIS WILL RESULT IN A MODEST NOCTURNAL
SURGE. SOUTHWEST WINDS WILL INCREASE INTO THE 10-15 KT RANGE ACROSS
MOST OF THE WATERS...PERHAPS AS HIGH AS A SOLID 15 KT FOR THE OUTER
GEORGIA WATERS. SEAS ARE EXPECTED TO INCREASE INTO THE 2-3 FT RANGE
BY EARLY SUNDAY MORNING.
NO HIGHLIGHTS EXPECTED THROUGH THE PERIOD. ATLANTIC HIGH PRESSURE
WILL REMAIN CENTERED SOUTH AND EAST OF THE WATERS...WITH A TROUGH OF
LOWER PRESSURE INLAND. THIS WILL KEEP SOUTHWEST WINDS OF 15 KNOTS OR
LESS AND SEAS 3 FT OR LESS. EXPECT SOME NOCTURNAL SURGING EACH
EVENING THROUGH VERY EARLY MORNING...WITH WINDS OF 15-20 KTS.
&&
.EQUIPMENT...
THE CHARLESTON SC WSR-88D /KCLX/ REMAINS OUT OF SERVICE DUE TO A
SIGNIFICANT MECHANICAL FAILURE. REPAIR WORK CONTINUES AND THE
RADAR MAY BE OPERATIONAL AS EARLY AS AUGUST 20TH OR 21ST. UNTIL
THE RADAR IS RETURNED TO SERVICE...THE FOLLOWING RADARS CAN BE
USED: KJAX...KJGX...KVAX...KCAE AND KLTX.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...BSH
SHORT TERM...RFM
LONG TERM...JRL
AVIATION...BSH
MARINE...BSH/RFM
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
122 PM EDT SAT AUG 16 2014
.SYNOPSIS...
HIGH PRESSURE EXTENDING FROM THE ATLANTIC WESTWARD ALONG THE GULF
COAST WILL DOMINATE THROUGH MONDAY. THIS FEATURE WILL KEEP THE
FORECAST AREA MAINLY DRY WITH SEASONABLE TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
THIS AFTERNOON...THE LATEST ANALYSIS INDICATED A WEAK PRESSURE PATTERN.
MOISTURE WAS SHALLOW. DESPITE STRONG HEATING THE THUNDERSTORM
CHANCE IS LOW BECAUSE OF LIMITED MOISTURE AND THE LACK OF A WELL-
DEFINED SURFACE FEATURE. BELIEVE ANY THUNDERSTORMS WILL BE
ISOLATED AND MAINLY CONFINED TO A FEW LOCATIONS IN THE EAST
SECTION OF THE FORECAST AREA WHERE DEWPOINT TEMPERATURES WERE
HIGHER. THE 11Z HRRR CONFINED THUNDERSTORMS TO NEAR THE SEA-BREEZE
FRONT AND JUST EAST OF THE FORECAST AREA THROUGH 02Z.
TONIGHT...THE SURFACE RIDGE TO OUR SOUTH WILL CONTINUE TO DOMINATE.
ANY THUNDERSTORMS SHOULD DISSIPATE THIS EVENING WITH THE LOSS OF
HEATING. THE TEMPERATURE GUIDANCE WAS CONSISTENT. LINGERING LOW-
LEVEL MOISTURE UNDER THE NOCTURNAL INVERSION MAY SUPPORT FOG. THE
MODELS INDICATE DRYING WITH THE WESTERLY COMPONENT TO THE LOW-
LEVEL FLOW SO FOG WILL LIKELY NOT BE AS EXTENSIVE AS WHAT
OCCURRED LAST NIGHT. EXPECT PATCHY FOG.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
A DRY FORECAST IS ON TAP THROUGH SUNDAY AND SUNDAY NIGHT WITH
TEMPERATURES SUNDAY AFTERNOON A LITTLE ABOVE NORMAL IN THE MID
90S.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
ZONAL UPPER LEVEL FLOW ON MONDAY SLOWLY EVOLVES INTO NW FLOW ALOFT
BY THE END OF THE WEEK AS A RIDGE OF HIGH PRESSURE BUILDS JUST TO
OUR WEST. LOW LEVEL MOISTURE FLUX IS FROM THE WEST TO NORTHWEST
THROUGH THE PERIOD SO NOT A LOT OF MOISTURE TO SUPPORT
PRECIPITATION. MODELS INDICATE AN UPPER WAVE MOVING EAST OVER THE
AREA MONDAY AFTERNOON INTO TUESDAY WHICH MAY BE A FORCING
MECHANISM FOR CONVECTION. POPS ARE GENERALLY 10 TO 20 PERCENT AT
NIGHT AND 20 TO 30 PERCENT DURING THE DAY. TEMPS ABOVE NORMAL WITH
BUILDING RIDGE AND INSTABILITY MAY SUPPORT WIDELY SCATTERED MAINLY
DIURNAL CONVECTION. GFS SHOWS BACK DOOR FRONT NEXT SATURDAY BUT
THAT IS STILL A WAYS OFF.
&&
.AVIATION /17Z SATURDAY THROUGH WEDNESDAY/...
EXPECT MAINLY VFR CONDITIONS CONTINUING THROUGH THIS EVENING. ANY
THUNDERSTORMS SHOULD BE ISOLATED BECAUSE OF SHALLOW MOISTURE. THE
CHANCE IS TOO LOW TO INCLUDE IN THE TERMINAL FORECASTS AT THIS
TIME. THE PRESSURE GRADIENT WILL BE WEAK AND THERE WILL BE
VARIABILITY IN THE WIND DIRECTION. NOCTURNAL COOLING AND LINGERING
LOW-LEVEL MOISTURE MAY SUPPORT STRATUS AND FOG AGAIN EARLY SUNDAY
MORNING. SOME DRYING WILL OCCUR IN THE WEST-SOUTHWEST LOW-LEVEL
FLOW. HOWEVER...FORECASTED CONDITIONS MORE PESSIMISTIC THAN THE
GFS AND NAM MOS MAINLY BASED ON WHAT OCCURRED LAST NIGHT. THE
MODELS MAY BE TOO FAST WITH THE DRYING IN THIS WEAK FLOW PATTERN.
EXTENDED AVIATION OUTLOOK...MVFR OR IFR CONDITIONS POSSIBLE IN
LATE NIGHT AND EARLY MORNING FOG. SCATTERED AFTERNOON AND EVENING
THUNDERSTORMS ALSO MAY BRING RESTRICTIONS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
108 PM EDT SAT AUG 16 2014
.SYNOPSIS...
HIGH PRESSURE EXTENDING FROM THE ATLANTIC WESTWARD ALONG THE GULF
COAST WILL DOMINATE THROUGH MONDAY. THIS FEATURE WILL KEEP THE
FORECAST AREA MAINLY DRY WITH SEASONABLE TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
THIS AFTERNOON...THE LATEST ANALYSIS INDICATED A WEAK PRESSURE PATTERN.
MOISTURE WAS SHALLOW. DESPITE STRONG HEATING THE THUNDERSTORM
CHANCE IS LOW BECAUSE OF LIMITED MOISTURE AND THE LACK OF A WELL-
DEFINED SURFACE FEATURE. BELIEVE ANY THUNDERSTORMS WILL BE
ISOLATED AND MAINLY CONFINED TO A FEW LOCATIONS IN THE EAST
SECTION OF THE FORECAST AREA WHERE DEWPOINT TEMPERATURES WERE
HIGHER. THE 11Z HRRR CONFINED THUNDERSTORMS TO NEAR THE SEA-BREEZE
FRONT AND JUST EAST OF THE FORECAST AREA THROUGH 02Z.
TONIGHT...THE SURFACE RIDGE TO OUR SOUTH WILL CONTINUE TO DOMINATE.
ANY THUNDERSTORMS SHOULD DISSIPATE THIS EVENING WITH THE LOSS OF
HEATING. THE TEMPERATURE GUIDANCE WAS CONSISTENT. LINGERING LOW-
LEVEL MOISTURE UNDER THE NOCTURNAL INVERSION MAY SUPPORT FOG. THE
MODELS INDICATE DRYING SO THE FOG WILL LIKELY NOT BE AS EXTENSIVE
AS WHAT OCCURRED LAST NIGHT. EXPECT PATCHY FOG.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
A DRY FORECAST IS ON TAP THROUGH SUNDAY AND SUNDAY NIGHT WITH
TEMPERATURES SUNDAY AFTERNOON A LITTLE ABOVE NORMAL IN THE MID
90S.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
ZONAL UPPER LEVEL FLOW ON MONDAY SLOWLY EVOLVES INTO NW FLOW ALOFT
BY THE END OF THE WEEK AS A RIDGE OF HIGH PRESSURE BUILDS JUST TO
OUR WEST. LOW LEVEL MOISTURE FLUX IS FROM THE WEST TO NORTHWEST
THROUGH THE PERIOD SO NOT A LOT OF MOISTURE TO SUPPORT
PRECIPITATION. MODELS INDICATE AN UPPER WAVE MOVING EAST OVER THE
AREA MONDAY AFTERNOON INTO TUESDAY WHICH MAY BE A FORCING
MECHANISM FOR CONVECTION. POPS ARE GENERALLY 10 TO 20 PERCENT AT
NIGHT AND 20 TO 30 PERCENT DURING THE DAY. TEMPS ABOVE NORMAL WITH
BUILDING RIDGE AND INSTABILITY MAY SUPPORT WIDELY SCATTERED MAINLY
DIURNAL CONVECTION. GFS SHOWS BACK DOOR FRONT NEXT SATURDAY BUT
THAT IS STILL A WAYS OFF.
&&
.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
EXPECT MAINLY VFR CONDITIONS CONTINUING THROUGH THIS EVENING. ANY
THUNDERSTORMS SHOULD BE ISOLATED BECAUSE OF SHALLOW MOISTURE. THE
CHANCE IS TOO LOW TO INCLUDE IN THE TERMINAL FORECASTS AT THIS
TIME. THE PRESSURE GRADIENT WILL BE WEAK AND THERE WILL BE
VARIABILITY IN THE WIND DIRECTION. NOCTURNAL COOLING AND LINGERING
LOW-LEVEL MOISTURE MAY SUPPORT STRATUS AND FOG AGAIN EARLY SUNDAY
MORNING. FORECASTED CONDITIONS MORE PESSIMISTIC THAN THE GFS AND
NAM MOS MAINLY BASED ON WHAT OCCURRED LAST NIGHT. THE MODELS MAY
BE TOO FAST WITH THE DRYING IN THIS WEAK FLOW PATTERN.
EXTENDED AVIATION OUTLOOK...MVFR OR IFR CONDITIONS POSSIBLE IN
LATE NIGHT AND EARLY MORNING FOG. SCATTERED AFTERNOON AND EVENING
THUNDERSTORMS ALSO MAY BRING RESTRICTIONS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1250 PM EDT SAT AUG 16 2014
.SYNOPSIS...
HIGH PRESSURE EXTENDING FROM THE ATLANTIC WESTWARD ALONG THE GULF
COAST WILL DOMINATE THROUGH MONDAY. THIS FEATURE WILL KEEP THE
FORECAST AREA MAINLY DRY WITH SEASONABLE TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
THIS AFTERNOON...THE LATEST ANALYSIS INDICATED A WEAK PRESSURE PATTERN.
MOISTURE WAS SHALLOW. DESPITE STRONG HEATING THE THUNDERSTORM
CHANCE IS LOW BECAUSE OF LIMITED MOISTURE AND THE LACK OF A WELL-
DEFINED SURFACE FEATURE. BELIEVE ANY THUNDERSTORMS WILL BE
ISOLATED AND MAINLY CONFINED TO A FEW LOCATIONS IN THE EAST
SECTION OF THE FORECAST AREA WHERE DEWPOINT TEMPERATURES WERE
HIGHER. THE 14Z HRRR CONFINED THUNDERSTORMS TO NEAR THE SEA-BREEZE
FRONT AND JUST EAST OF THE FORECAST AREA.
TONIGHT...THE SURFACE RIDGE TO OUR SOUTH WILL CONTINUE TO DOMINATE.
ANY THUNDERSTORMS SHOULD DISSIPATE THIS EVENING WITH THE LOSS OF
HEATING. THE TEMPERATURE GUIDANCE WAS CONSISTENT. LINGERING LOW-
LEVEL MOISTURE UNDER THE NOCTURNAL INVERSION MAY SUPPORT FOG. THE
MODELS INDICATE DRYING SO THE FOG WILL LIKELY NOT BE AS EXTENSIVE
AS WHAT OCCURRED LAST NIGHT. EXPECT PATCHY FOG.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
A DRY FORECAST IS ON TAP THROUGH SUNDAY. FOR THE MOST PART SUNDAY
SHOULD BE A REPEAT OF SATURDAY...WITH MAINLY ISOLATED RAINFALL
ACROSS THE COASTAL PLAIN. OVERNIGHT LOWS TONIGHT WILL FALL TO
AROUND 70...WITH HIGHS ON SUNDAY IN THE LOWER TO MIDDLE 90S.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
NO CHANGES MADE IN THE LONG TERM. THE GFS AND ECMWF DISPLAY
RIDGING EXTENDING FROM THE ATLANTIC WESTWARD NEAR THE GULF COAST
THROUGH THE MEDIUM- RANGE PERIOD. FARTHER NORTH THE MODELS SHOW
LEE-SIDE TROUGHING IN THE FORECAST AREA DURING MUCH OF THE PERIOD.
A FRONT DROPPING SOUTHWARD MAY EXTEND THROUGH THE FORECAST AREA
DURING PART OF THE PERIOD. THE RIDGE TO THE SOUTH SHOULD LIMIT
MOISTURE. THE MODELS SHOW STRONGER CONVERGENCE AND DEEPER MOISTURE
NORTH OF THE FORECAST AREA. THE GFS...ECMWF...AND EKD MOS HAVE
POPS 20 TO 30 PERCENT. EXPECT HIGH TEMPERATURES ABOVE NORMAL WITH
THE RIDGE TO THE SOUTH DIRECTING A WESTERLY FLOW INTO THE FORECAST
AREA. THE GUIDANCE HAS HIGHS MAINLY IN THE MIDDLE 90S THROUGH THE
PERIOD.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
EXPECT MAINLY VFR CONDITIONS CONTINUING THROUGH THIS EVENING. ANY
THUNDERSTORMS SHOULD BE ISOLATED BECAUSE OF SHALLOW MOISTURE. THE
CHANCE IS TOO LOW TO INCLUDE IN THE TERMINAL FORECASTS AT THIS
TIME. THE PRESSURE GRADIENT WILL BE WEAK AND THERE WILL BE
VARIABILITY IN THE WIND DIRECTION. NOCTURNAL COOLING AND LINGERING
LOW-LEVEL MOISTURE MAY SUPPORT STRATUS AND FOG AGAIN EARLY SUNDAY
MORNING. FORECASTED CONDITIONS MORE PESSIMISTIC THAN THE GFS AND
NAM MOS MAINLY BASED ON WHAT OCCURRED LAST NIGHT. THE MODELS MAY
BE TOO FAST WITH THE DRYING IN THIS WEAK FLOW PATTERN...BUT STILL
WITH SOME DRYING THE FOG AND STRATUS LIKELY WILL NOT BE AS
EXTENSIVE COMPARED TO LAST NIGHT.
EXTENDED AVIATION OUTLOOK...MVFR OR IFR CONDITIONS POSSIBLE IN
LATE NIGHT AND EARLY MORNING FOG. SCATTERED AFTERNOON AND EVENING
THUNDERSTORMS ALSO MAY BRING RESTRICTIONS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
101 PM CDT SAT AUG 16 2014
.DISCUSSION...
339 AM CDT
SHORT TERM...THROUGH SATURDAY NIGHT...
FOR THE REMAINDER OF THE NIGHT AND INTO SATURDAY MORNING...HIGH
PRESSURE CONTINUES TO SLIDE SOUTHEAST INTO THE CENTRAL APPALACHIANS
WITH A RIDGE AXIS EXTENDING NORTHWEST INTO SOUTHERN MINNESOTA. LOW
PRESSURE MOVING THROUGH ONTARIO IS DRAGGING A COLD FRONT INTO THE
UPPER GREAT LAKES REGION. WITH CLEAR SKIES AND LIGHT WINDS UNDER
THE RIDGE AXIS...SOME PATCHY FOG IS FORMING OVER NWRN AND NCNTRL IL
WHERE TEMPERATURES HAVE BEEN ABLE TO RADIATE LOWER AND A RETURN FLOW
OF MOISTURE AROUND THE WESTERN PERIPHERY OF THE HIGH HAS RAISED
DEWPOINTS INTO UPPER 50S. THE PATCHY FOG MAY INCREASE IN COVERAGE
THROUGH THE REMAINDER OF THE LATE NIGHT HOURS...BUT DO NOT
ANTICIPATE WIDESPREAD DENSE FOG.
INTO THE MORNING HOURS...THE INITIAL CONCERN WILL BE THE SPREAD OF
SHRA/TSRA INTO WEST CENTRAL IL ASSOCIATED WITH A VERY SLOW MOVING
SHORTWAVE OVER SCNTRL IA/NCNTRL MO. THE TREND OF THIS SYSTEM HAS
BEEN ON A MORE SOUTHERLY TRACK SIMILAR TO WHAT THE ECMWF HAD BEEN
ADVERTISING...WHICH WOULD FOCUS THE GREATEST PCPN CHANCES OVER THE
SRN PORTIONS OF THE CWA. FOR THE TODAY AND TONIGHT...HAVE LARGELY
FOLLOWED THE LOCAL WRFARW GUIDANCE WHICH IS WELL INITIALIZED AND
FOLLOWS THE MORE SOUTHERLY AND SLOW MOVING TRACK OF THE MAIN
SHORTWAVE. EARLY THIS MORNING...SHOWERS AND THUNDERSTORMS HAVE BEEN
MOVING THROUGH IA AND MO...AND ARE CROSSING THE MISSISSIPPI RIVER
INTO WEST CENTRAL IL. THE PCPN IS LARGELY FOCUSED ON THE NOSE OF A
STRONG LOW LEVEL JET. THIS SHOULD GRADUALLY PROGRESS EWD...AND
ANTICIPATE THAT THE MAIN AREA OF PCPN OVER THE CWA SHOULD GENERALLY
REMAIN SOUTH OF THE I-80 CORRIDOR. HOWEVER...THERE IS STILL A
SLIGHT CHANCE THAT SOME SCT SHRA OR AN ISOLATED THUNDERSTORM COULD
SNEAK INTO NERN IL...INCLUDING THE CHICAGO METRO AREA LATE THIS
AFTERNOON. HOWEVER...THE CHANCES SHOULD BE LOW AND COVERAGE SHOULD
BE SPARSE. FOR THE SOUTHERN PORTIONS OF THE CWA WHERE THE BULK OF
THE PCPN AFFECTING THE AREA SHOULD FALL...HIGH PWAT AIR AND SLOW
PROGRESSION UNDER GENERALLY LIGHT WINDS ALOFT COULD LEAD TO SOME
LOCALLY HEAVY RAINFALL WITH SOME OF THE STRONGER STORM CELLS.
WINDS TODAY SHOULD BE PREVAILING SWLY AS THE AS THE HIGH SLIDES TO
THE SOUTHEAST AND THE SFC LOW SLOWLY TRACKS ESEWD. WITH A WEAK
GRADIENT...WINDS SHOULD GENERALLY BE LESS THAN 10 MPH TODAY...BUT
THE STRONGER SWLY WINDS ALOFT ASSOCIATED WITH THE LOW LEVEL JET
AHEAD OF THE SFC LOW SHOULD PREVENT LAKE BREEZE DEVELOPMENT IN THE
ABSENCE OF A LAKE BREEZE...WARMER AIR SHOULD BE ABLE TO SPREAD UP TO
THE LAKEFRONT WITH TEMPS ARND 80F ACROSS THE AREA.
THE SECOND AREA OF CONCERN WILL BE THE COLD FRONT TRACKING DOWN LAKE
MICHIGAN AND THROUGH WISCONSIN. EXPECT THAT THE PORTION OF THE
FRONT OVER THE LAKE WILL SURGE FASTER THAN THE PORTION OVERLAND AND
EXPECT THAT THE FRONT SHOULD PUSH INTO SOUTHERN LAKE MICHIGAN AND
NERN IL DURG THE LATE EVENING HOURS. AS THE FRONT MOVES INTO NERN
IL...THE ZONE OF CONVERGENCE ASSOCIATED WITH THE FRONT WILL BE
DISRUPTED BY THE CYCLONIC FLOW AROUND THE SFC LOW...WHICH SHOULD
MOVE INTO WCNTRL IL LATE TONIGHT. SO...WITH THE CONVERGENCE ALONG
THE FRONT DIMINISHING OVERNIGHT AS THE FRONT PUSHES SOUTH...THE
CHANCES FOR PCPN ALONG THE BOUNDARY SHOULD ALSO DECREASE.
SO...WILL STILL CARRY SLIGHT CHANCE POPS AS THE BOUNDARY PUSHES
INTO NERN IL. THE MAIN IMPACT OF THE FRONT SHOULD BE TO DRAW LAKE
COOLED AIR INLAND WITH INCREASING LOW STRATUS AND POSSIBLE SOME
FOG DEVELOPMENT.
KREIN
SUNDAY THROUGH MONDAY...
OPERATIONAL SOLUTIONS HAVE CONTINUED TO POINT TOWARDS A SLIGHTLY
STRONGER SFC RIDGE OVER CENTRAL ONTARIO SLIDING SOUTH AND PUSHING A
QUASI-STATIONARY BOUNDARY FURTHER SOUTH SUN INTO CENTRAL IL. IF THIS
SOLUTION VERIFIES MUCH OF THE FORECAST AREA SUN WILL BE UNDER A COOL
AND RELATIVELY DRIER NORTHEAST FLOW. HAVE HELD ONTO LOW CHC POPS FOR
AREAS SOUTH OF I-80...BUT HAVE INCREASED CONFIDENCE THAT THIS TOO
WILL END UP BEING TRIMMED. THERE REMAINS SOME MID-LVL
MOISTURE...WITH MUCH OF THE GUIDANCE MEMBERS POINTING TOWARDS SOME
MID/UPR LVL CLOUDS. THAT BEING SAID HIGHS WILL LIKELY STRUGGLE TO
WARM MUCH BEYOND THE LOW/MID 70S. THE EXCEPTION WILL BE THE FAR
SOUTH/SOUTHWEST WHERE TEMPS COULD STILL PUSH INTO THE UPR 70S.
WEAK MID-LVL WAVE THAT WAS THOUGHT TO BRING PRECIP BACK INTO THE
FORECAST AREA SUN NGT/MON IS ALSO TRENDING FURTHER SOUTH IN THIS
TIME FRAME. GUIDANCE DOES TRY TO SLIDE THIS WEAK WAVE EAST THRU
SOUTHERN IL/IN...WITH SOME MID-LVL DIFFLUENCE ARRIVING OVER THE CWFA
SUN EVE. EXPECT MUCH OF SUN NGT TO END UP BEING DRY FOR NORTHERN
IL/NORTHWEST IN.
WITH A WEAK WAVE PUSHING EAST INTO SOUTHEAST IN ALONG WITH A WEAK
UPR LVL VORT SLIDING EAST ACROSS THE CENTRAL/NORTHERN PLAINS MON...A
GOOD PORTION OF MON COULD END UP BEING DRY WITH SOME CLOUDS. BY MON
EVE BETTER VORTICITY IN THE MID-LVLS ARRIVES WITH SOME INCREASED
MOISTURE BEING PROGGED IN THE LLVLS BY GUIDANCE. SO HAVE HELD ONTO
CHC POPS MON NGT FOCUSED IN THE WESTERN CWFA...MEANWHILE EXPECT THE
EASTERN HALF OF THE FORECAST AREA TO REMAIN DRY MON NGT. THE
CONTINUED NORTHEAST FLOW WILL KEEP TEMPS ONCE AGAIN SUB-SEASONAL FOR
MON...WITH HIGHS GENERALLY IN THE 70S. WINDS WILL BE SLOWLY TURNING
EAST/SOUTHEAST MON NGT WITH INCREASING LLVL MOISTURE...AND WILL
LIKELY HOLD TEMPS UP IN THE LOW 60S.
TUESDAY THROUGH FRIDAY...
THROUGHOUT THE EXTENDED PERIODS...ENSEMBLES HAVE THE NORTH ATLANTIC
RIDGE TRYING TO WEAKEN THEN RETROGRADING WEST/SOUTHWEST ACROSS
EASTERN CANADA. MEANWHILE THE WEAK TROUGHING ACROSS THE GREAT LAKES
WILL DISSOLVE AS PAC-NW RIDGING DEVELOPS AND CENTRAL ROCKIES TROUGHS
FORMS. THERE IS STILL CONSIDERABLE SPREAD AMONGST MEMBERS IN THE
EXTENDED...HOWEVER THERE IS A GENERAL THEME OF THE AFOREMENTIONED
OUTCOME.
OPERATIONAL SOLUTIONS FROM TUE THRU FRI PROG SOME FLATTENING IN THE
FLOW...OR A TRANSITION INTO A SEMI-ZONAL SETUP. THIS WOULD POINT
TOWARDS A RELATIVELY ACTIVE OR AT LEAST PERIODIC WAVES TRAVERSING
THE NORTHERN CONUS WITH OCCASIONAL CHANCES FOR
SHOWERS/THUNDERSTORMS. THEN CLOSER TO THE LATER PERIODS OF THE
CURRENT EXTENDED...THERE DOES APPEAR TO BE SOME LEANING IN GUIDANCE
THAT RIDGING WILL DEVELOP WITH A STEADY WARMING TREND. LLVL MOISTURE
IS ALSO PROGGED TO INCREASE LATE WEEK...WITH HIGHS NEARING THE
MID/UPR 80S.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* WINDS 8-12 KT THROUGH EARLY AFTERNOON THEN EXPECTED TO DECREASE
SLIGHTLY INTO LATE AFTERNOON.
* LOW CHANCE FOR A SHOWER OR SPRINKLE THIS AFTERNOON/EVENING.
* MVFR EXPECTED OVERNIGHT/SUNDAY MORNING WITH IFR POSSIBLE TOWARD
DAYBREAK. SCATTERING/LIFTING INTO SUNDAY AFTERNOON.
* NORTHEAST WINDS AROUND 10 KT SUNDAY.
MDB
//DISCUSSION...UPDATED 18Z...
AN UPPER LEVEL LOW CONTINUES TO SLOWLY SPIN EAST-SOUTHEAST ACROSS
SOUTHEAST IOWA. THIS IS DRIVING SOME SHOWER ACTIVITY ACROSS
CENTRAL ILLINOIS WITH JUST A FEW LIGHT RADAR RETURNS MOVING INTO
NORTHERN IL AND NORTHWEST IN. EXPECT THE BULK OF THE MORE
WIDESPREAD PRECIP TO OCCUR DOWN TOWARDS A PNT-RZL LINE WITH
SCATTERED COVERAGE UP TOWARDS JOT-VPZ AND ISOLATED POTENTIAL TO
THE NORTH. GYY MAY HAVE THE BEST CHANCE FOR A SHOWER. CANNOT RULE
OUT SOME ISOLATED TS. ABUNDANT CLOUD COVER CONTINUES ACROSS THE
AREA IN SEVERAL LAYERS WITH MAINLY VFR ACROSS THE AREA BUT WITH
MVFR MORE ABUNDANT BACK INTO SOUTHEAST IOWA AND WEST CENTRAL IL.
WINDS REMAIN QUITE VARIABLE WITH A WEAK RIDGE AXIS ANALYZED FROM
EAST CENTRAL TO NORTHWEST IL. A SOUTHWEST DIRECTION PREVAILS WITH
HIGHEST SPEEDS AT ORD/MDW WHERE HIGHER CLOUD COVERAGE HAS BEEN
MORE INTERMITTENT. THIS HAS ALLOWED MIXING TO DEEPEN AND LED TO
10-12 KT WIND SPEEDS AT TIMES. WINDS JUST OFF THE SURFACE SHOULD
START TO EASE UP THROUGH THE AFTERNOON SO THERE SHOULD BE A SLIGHT
DOWN TICK IN THE RANGE OF WIND SPEEDS. THE CAVEAT WOULD BE IF
THERE IS A DECREASE IN CLOUD COVER WHICH MAY KEEP WINDS CLOSER TO
WHERE THEY HAVE BEEN THROUGH MIDDAY.
A COOL FRONTAL BOUNDARY MOVES SOUTHWARD ACROSS THE AREA TONIGHT.
THIS IS EXPECTED TO BRING A PERIOD OF MVFR CIGS WITH IT AND MVFR
IS BEING REPORTED UPSTREAM. WITH COOL ADVECTION AND FLOW OFF THE
LAKE SOME IFR IS POSSIBLE TOWARD DAYBREAK BUT WILL KEEP THE IFR
LEVEL CLOUDS SCATTERED SUNDAY MORNING FOR NOW. SOME VSBY REDUCTION
IS POSSBLE BUT AM LESS CONFIDENT IN THIS. LOW CLOUD COVERAGE IS
EXPECTED TO LIFT THROUGH THE LATE MORNING/EARLY AFTERNOON AND MVFR
MAY BE IN PLACE AT SOME POINT DURING THE AFTERNOON. WINDS WILL
TURN NORTHEASTERLY BEHIND THE FRONT TONIGHT.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM-HIGH CONFIDENCE IN WIND SPEEDS THROUGH EARLY
AFTERNOON...MEDIUM CONFIDENCE IN A SLIGHT DOWNWARD TREND INTO
LATE AFTERNOON.
* HIGH CONFIDENCE THAT PRECIP CHANCE IS LOW.
* MEDIUM-HIGH CONFIDENCE IN PERIOD OF MVFR CIGS TONIGHT/SUNDAY
MORNING. LOW CONFIDENCE IN IFR OCCURRING. LOW-MEDIUM CONFIDENCE
IN VSBY REDUCTION. MEDIUM CONFIDENCE IN TIMING OF IMPROVEMENT
SUNDAY.
* HIGH CONFIDENCE IN WINDS FOR SUNDAY.
MDB
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT THROUGH MONDAY...VFR. WX NIL.
MONDAY NIGHT THROUGH FRIDAY...PERIODIC CHANCES FOR SHRA/TSRA.
&&
.MARINE...
400 AM CDT
AS HIGH PRESSURE SLIDES OFF THE MID ATLANTIC COAST TODAY...LOW
PRESSURE WILL MOVE SLOWLY THROUGH THE MIDDLE MISSISSIPPI VALLEY
WHILE ANOTHER LOW OVER ONTARIO DRAGS A COLD FRONT DOWN THE LENGTH
OF LAKE MICHIGAN. A STRENGTHENING SWLY GRADIENT AHEAD OF THE COLD
FRONT WILL BRING INCREASING WINDS TO THE LAKE THROUGH THE MORNING
HOURS...APPROACHING 30 KT OVER THE NRN PORTIONS OF THE LAKE WHERE
THE GRADIENT WILL BE STRONGEST...WHILE WINDS OVER THE SRN
PORTIONS OF THE LAKE WILL STILL BE RATHER BRISK AT 15-25KT. THE
COLD FRONT WILL BEGIN TO PUSH OVER THE FAR NRN END OF THE LAKE
SHORTLY AFTER DAYBREAK AND STEADILY MOVE DOWN THE LAKE THROUGH THE
DAY TODAY. WINDS WILL QUICKLY TURN TO NLY FOLLOWING THE FROPA AND
WITH THE INITIAL SURGE OF COOLER AIR...WINDS SHOULD RAMP BACK UP
TO 30KT IMMEDIATELY FOLLOWING THE FROPA. HOWEVER...AS ANOTHER AREA
OF HIGH PRESSURE QUICKLY DROPS INTO THE THE UPPER GREAT LAKES
SATURDAY NIGHT...WINDS WILL DROP OFF WHILE VEERING TO MORE NELY.
AS THE HIGH CONTINUES TO BUILD TO THE EAST...WINDS WILL CONTINUE
TO VEER TO ELY AND THEN SELY SUNDAY NIGHT AND MONDAY. SELY WINDS
WILL THEN PERSIST ACROSS THE LAKE UNTIL MID WEEK AS ANOTHER LOW
PRESSURE SYSTEM DROPS OUT OF THE NRN PLAINS AND APPROACHES THE WRN
GREAT LAKE REGION BY LATE TUESDAY OR WEDNESDAY.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1232 PM CDT Sat Aug 16 2014
.UPDATE...
ISSUED AT 946 AM CDT SAT AUG 16 2014
Incoming area of showers and scattered storms has been showing
some fading over the last couple hours as it crosses the Illinois
River. Latest HRRR shows a narrower band of showers pushing past
the I-55 corridor midday, with some additional development
occurring to our west this afternoon near a low in southeast Iowa.
East central and southeast Illinois will see more in the way of
scattered showers through the day. Have sent some grid updates
earlier to reflect the current trends. Temperatures currently on
track and should mainly be confined to the 70s today with the
widespread cloud cover.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 323 AM CDT SAT AUG 16 2014
MCS over southern Iowa into northern Missouri early this morning
tracking slowly to the east and this feature will be our main
concern through tonight. Well out ahead of the MCS to our west, we
have had some isolated showers develop over parts of central and
east central Illinois during the past several hours. Unlike last
night at this time when we were seeing dew points in the upper 40s
to lower 50s over our northeast counties, most areas have seen the
dew points climb back well into the 60s.
Most of the short term models move the MCV associated with the
current convection out in northern Missouri/southern Iowa slowly
into southeast Iowa by late this afternoon. Current band of showers
and isolated storms will shift slowly east of the Mississippi River
by dawn this morning and continue to edge slowly east during the
morning with a gradual decrease in areal coverage as the main
support from the low level jet wanes with time early this morning.
The extensive cloud cover and showers will keep temps below guid in
most areas except the far east where the rain will not get into that
part of our forecast area until later today.
Most of the hi-resolution model solutions redevelop the convection
to the east of the MCV later this afternoon into parts of west
central Illinois and then shift the precip to the east tonight as
the vort center tracks into central IL by Sunday morning.
Precipitable water values still forecast well above 2 inches tonight
with warm cloud depths above 3km indicating some very efficient
rains with any convection that develops just to the east of the vort
center tonight. Upper winds are also forecast to weaken considerably
indicating the storms that do develop near or to the east/southeast
of the MCV will be slow movers and threaten parts of our area with
heavy rainfall. However, one negative factor for widespread heavy
rainfall will be with a much weaker low level jet than what we are
seeing out to our west tonight. Still, with the high PWAT values in
place, any storms that develop late this afternoon thru this evening
will be capable of producing high rainfall rates along and to the
east of the MCV overnight.
&&
.LONG TERM...(Sunday through Friday)
ISSUED AT 323 AM CDT SAT AUG 16 2014
Upper disturbance remaining over the FA Sunday morning in the
models. Models not really responding to the MCV equally as the low
moves out to the east. A lot of uncertainty as the day progresses,
but the better chances for the continuation of precip remain in the
east and southeast as the system tracks out to the east, just north
of the Ohio River Valley. Models dry out briefly for early Monday
morning, and chances through the day on Monday starting to drop off
a bit. Less amplified flow over the country looking messy through
the work week. Heat that has been building over the desert
southwest makes its way into the region warming up the temps to far
more of a summer pattern that has been to this point. Temps in the
upper 80s/lower 90s Wed-Friday. Weak flow aloft and a series of
small waves dipping into the Great Lakes/Midwest keeping ILX in an
unsettled weather pattern and pops dominate the extended forecast
with periodic chances for precip. Models diverge significantly
going into the weekend with the GFS building in a ridge for the
Midwest and southern Plains, while the ECMWF remains more
progressive with pushing a trof across the nrn tier of the CONUS.
Should the forecast go more the way of the GFS with subsequent
issues, the temperatures may need to be bumped up a couple degrees
under a persistent ridge. But with the ECMWF in direct opposition
and the timing of waves such a question mark...not willing to
deviate too much from what the AllBlend has in the grids just yet.
All in all, a warm forecast with periodic showers. PW values
trending down from where they were 24 hrs ago, but chances for some
of the thunderstorms to produce some heavy rain. Upper dynamics not
particularly alarming any one day just yet...but this pattern is
more reminiscent of summer than what has been around so far.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
ISSUED AT 1232 PM CDT SAT AUG 16 2014
Widespread MVFR ceilings across most of central Illinois at
midday. This should linger for a few hours, before lifting a bit
late afternoon. So far the showers have only been scattered at the
TAF sites and the main wave has been eroding, with KSPI the main
threat from it. However, thunder has been diminishing and have
removed the VCTS mentions from the TAFs until this evening. Made
little change to the forecasts beyond 06Z, with MVFR to
potentially IFR conditions developing and continuing into Sunday
morning.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEELHART
SHORT TERM...SMITH
LONG TERM...HJS
AVIATION...GEELHART
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1112 AM CDT SAT AUG 16 2014
.DISCUSSION...
339 AM CDT
SHORT TERM...THROUGH SATURDAY NIGHT...
FOR THE REMAINDER OF THE NIGHT AND INTO SATURDAY MORNING...HIGH
PRESSURE CONTINUES TO SLIDE SOUTHEAST INTO THE CENTRAL APPALACHIANS
WITH A RIDGE AXIS EXTENDING NORTHWEST INTO SOUTHERN MINNESOTA. LOW
PRESSURE MOVING THROUGH ONTARIO IS DRAGGING A COLD FRONT INTO THE
UPPER GREAT LAKES REGION. WITH CLEAR SKIES AND LIGHT WINDS UNDER
THE RIDGE AXIS...SOME PATCHY FOG IS FORMING OVER NWRN AND NCNTRL IL
WHERE TEMPERATURES HAVE BEEN ABLE TO RADIATE LOWER AND A RETURN FLOW
OF MOISTURE AROUND THE WESTERN PERIPHERY OF THE HIGH HAS RAISED
DEWPOINTS INTO UPPER 50S. THE PATCHY FOG MAY INCREASE IN COVERAGE
THROUGH THE REMAINDER OF THE LATE NIGHT HOURS...BUT DO NOT
ANTICIPATE WIDESPREAD DENSE FOG.
INTO THE MORNING HOURS...THE INITIAL CONCERN WILL BE THE SPREAD OF
SHRA/TSRA INTO WEST CENTRAL IL ASSOCIATED WITH A VERY SLOW MOVING
SHORTWAVE OVER SCNTRL IA/NCNTRL MO. THE TREND OF THIS SYSTEM HAS
BEEN ON A MORE SOUTHERLY TRACK SIMILAR TO WHAT THE ECMWF HAD BEEN
ADVERTISING...WHICH WOULD FOCUS THE GREATEST PCPN CHANCES OVER THE
SRN PORTIONS OF THE CWA. FOR THE TODAY AND TONIGHT...HAVE LARGELY
FOLLOWED THE LOCAL WRFARW GUIDANCE WHICH IS WELL INITIALIZED AND
FOLLOWS THE MORE SOUTHERLY AND SLOW MOVING TRACK OF THE MAIN
SHORTWAVE. EARLY THIS MORNING...SHOWERS AND THUNDERSTORMS HAVE BEEN
MOVING THROUGH IA AND MO...AND ARE CROSSING THE MISSISSIPPI RIVER
INTO WEST CENTRAL IL. THE PCPN IS LARGELY FOCUSED ON THE NOSE OF A
STRONG LOW LEVEL JET. THIS SHOULD GRADUALLY PROGRESS EWD...AND
ANTICIPATE THAT THE MAIN AREA OF PCPN OVER THE CWA SHOULD GENERALLY
REMAIN SOUTH OF THE I-80 CORRIDOR. HOWEVER...THERE IS STILL A
SLIGHT CHANCE THAT SOME SCT SHRA OR AN ISOLATED THUNDERSTORM COULD
SNEAK INTO NERN IL...INCLUDING THE CHICAGO METRO AREA LATE THIS
AFTERNOON. HOWEVER...THE CHANCES SHOULD BE LOW AND COVERAGE SHOULD
BE SPARSE. FOR THE SOUTHERN PORTIONS OF THE CWA WHERE THE BULK OF
THE PCPN AFFECTING THE AREA SHOULD FALL...HIGH PWAT AIR AND SLOW
PROGRESSION UNDER GENERALLY LIGHT WINDS ALOFT COULD LEAD TO SOME
LOCALLY HEAVY RAINFALL WITH SOME OF THE STRONGER STORM CELLS.
WINDS TODAY SHOULD BE PREVAILING SWLY AS THE AS THE HIGH SLIDES TO
THE SOUTHEAST AND THE SFC LOW SLOWLY TRACKS ESEWD. WITH A WEAK
GRADIENT...WINDS SHOULD GENERALLY BE LESS THAN 10 MPH TODAY...BUT
THE STRONGER SWLY WINDS ALOFT ASSOCIATED WITH THE LOW LEVEL JET
AHEAD OF THE SFC LOW SHOULD PREVENT LAKE BREEZE DEVELOPMENT IN THE
ABSENCE OF A LAKE BREEZE...WARMER AIR SHOULD BE ABLE TO SPREAD UP TO
THE LAKEFRONT WITH TEMPS ARND 80F ACROSS THE AREA.
THE SECOND AREA OF CONCERN WILL BE THE COLD FRONT TRACKING DOWN LAKE
MICHIGAN AND THROUGH WISCONSIN. EXPECT THAT THE PORTION OF THE
FRONT OVER THE LAKE WILL SURGE FASTER THAN THE PORTION OVERLAND AND
EXPECT THAT THE FRONT SHOULD PUSH INTO SOUTHERN LAKE MICHIGAN AND
NERN IL DURG THE LATE EVENING HOURS. AS THE FRONT MOVES INTO NERN
IL...THE ZONE OF CONVERGENCE ASSOCIATED WITH THE FRONT WILL BE
DISRUPTED BY THE CYCLONIC FLOW AROUND THE SFC LOW...WHICH SHOULD
MOVE INTO WCNTRL IL LATE TONIGHT. SO...WITH THE CONVERGENCE ALONG
THE FRONT DIMINISHING OVERNIGHT AS THE FRONT PUSHES SOUTH...THE
CHANCES FOR PCPN ALONG THE BOUNDARY SHOULD ALSO DECREASE.
SO...WILL STILL CARRY SLIGHT CHANCE POPS AS THE BOUNDARY PUSHES
INTO NERN IL. THE MAIN IMPACT OF THE FRONT SHOULD BE TO DRAW LAKE
COOLED AIR INLAND WITH INCREASING LOW STRATUS AND POSSIBLE SOME
FOG DEVELOPMENT.
KREIN
SUNDAY THROUGH MONDAY...
OPERATIONAL SOLUTIONS HAVE CONTINUED TO POINT TOWARDS A SLIGHTLY
STRONGER SFC RIDGE OVER CENTRAL ONTARIO SLIDING SOUTH AND PUSHING A
QUASI-STATIONARY BOUNDARY FURTHER SOUTH SUN INTO CENTRAL IL. IF THIS
SOLUTION VERIFIES MUCH OF THE FORECAST AREA SUN WILL BE UNDER A COOL
AND RELATIVELY DRIER NORTHEAST FLOW. HAVE HELD ONTO LOW CHC POPS FOR
AREAS SOUTH OF I-80...BUT HAVE INCREASED CONFIDENCE THAT THIS TOO
WILL END UP BEING TRIMMED. THERE REMAINS SOME MID-LVL
MOISTURE...WITH MUCH OF THE GUIDANCE MEMBERS POINTING TOWARDS SOME
MID/UPR LVL CLOUDS. THAT BEING SAID HIGHS WILL LIKELY STRUGGLE TO
WARM MUCH BEYOND THE LOW/MID 70S. THE EXCEPTION WILL BE THE FAR
SOUTH/SOUTHWEST WHERE TEMPS COULD STILL PUSH INTO THE UPR 70S.
WEAK MID-LVL WAVE THAT WAS THOUGHT TO BRING PRECIP BACK INTO THE
FORECAST AREA SUN NGT/MON IS ALSO TRENDING FURTHER SOUTH IN THIS
TIME FRAME. GUIDANCE DOES TRY TO SLIDE THIS WEAK WAVE EAST THRU
SOUTHERN IL/IN...WITH SOME MID-LVL DIFFLUENCE ARRIVING OVER THE CWFA
SUN EVE. EXPECT MUCH OF SUN NGT TO END UP BEING DRY FOR NORTHERN
IL/NORTHWEST IN.
WITH A WEAK WAVE PUSHING EAST INTO SOUTHEAST IN ALONG WITH A WEAK
UPR LVL VORT SLIDING EAST ACROSS THE CENTRAL/NORTHERN PLAINS MON...A
GOOD PORTION OF MON COULD END UP BEING DRY WITH SOME CLOUDS. BY MON
EVE BETTER VORTICITY IN THE MID-LVLS ARRIVES WITH SOME INCREASED
MOISTURE BEING PROGGED IN THE LLVLS BY GUIDANCE. SO HAVE HELD ONTO
CHC POPS MON NGT FOCUSED IN THE WESTERN CWFA...MEANWHILE EXPECT THE
EASTERN HALF OF THE FORECAST AREA TO REMAIN DRY MON NGT. THE
CONTINUED NORTHEAST FLOW WILL KEEP TEMPS ONCE AGAIN SUB-SEASONAL FOR
MON...WITH HIGHS GENERALLY IN THE 70S. WINDS WILL BE SLOWLY TURNING
EAST/SOUTHEAST MON NGT WITH INCREASING LLVL MOISTURE...AND WILL
LIKELY HOLD TEMPS UP IN THE LOW 60S.
TUESDAY THROUGH FRIDAY...
THROUGHOUT THE EXTENDED PERIODS...ENSEMBLES HAVE THE NORTH ATLANTIC
RIDGE TRYING TO WEAKEN THEN RETROGRADING WEST/SOUTHWEST ACROSS
EASTERN CANADA. MEANWHILE THE WEAK TROUGHING ACROSS THE GREAT LAKES
WILL DISSOLVE AS PAC-NW RIDGING DEVELOPS AND CENTRAL ROCKIES TROUGHS
FORMS. THERE IS STILL CONSIDERABLE SPREAD AMONGST MEMBERS IN THE
EXTENDED...HOWEVER THERE IS A GENERAL THEME OF THE AFOREMENTIONED
OUTCOME.
OPERATIONAL SOLUTIONS FROM TUE THRU FRI PROG SOME FLATTENING IN THE
FLOW...OR A TRANSITION INTO A SEMI-ZONAL SETUP. THIS WOULD POINT
TOWARDS A RELATIVELY ACTIVE OR AT LEAST PERIODIC WAVES TRAVERSING
THE NORTHERN CONUS WITH OCCASIONAL CHANCES FOR
SHOWERS/THUNDERSTORMS. THEN CLOSER TO THE LATER PERIODS OF THE
CURRENT EXTENDED...THERE DOES APPEAR TO BE SOME LEANING IN GUIDANCE
THAT RIDGING WILL DEVELOP WITH A STEADY WARMING TREND. LLVL MOISTURE
IS ALSO PROGGED TO INCREASE LATE WEEK...WITH HIGHS NEARING THE
MID/UPR 80S.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* SOUTHWEST WINDS VARIABLE BETWEEN 9 AND 12 KT THROUGH MID
AFTERNOON.
* LOW CHANCE FOR SHRA AND MINIMAL CHANCE FOR TSRA THIS AFTERNOON.
MDB
//DISCUSSION...UPDATED 16Z...
WIND SPEEDS CONTINUE TO VARY QUITE A BIT ACROSS THE TERMINALS WITH
ORD/MDW SEEING THE OVERALL HIGHEST SPEEDS. RANGE OF SPEEDS HAS
INCREASED FROM 7-10 KT INTO THE 9-12 KT RANGE AND EXPECT THIS TO
CONTINUE THROUGH EARLY AFTERNOON. WITH VARIABLE COVERAGE OF CLOUDS
CURRENTLY AT LOWER LEVELS...VARIABILITY IN SPEEDS IS SOMEWHAT HIGH
AS MIXING TRIES TO BECOME BETTER ESTABLISHED. OVERALL EXPECT SPEEDS
TO VARY A FEW KNOTS EITHER SIDE OF 10 KT. SPEEDS MAY START TO EASE
SLIGHTLY MID TO LATE AFTERNOON AS FORECAST SOUNDINGS SUGGEST WINDS
JUST ABOVE THE SURFACE EASING SLIGHTLY AND CLOUD COVER REMAINING
ABUNDANT.
MDB
FROM 12Z...
HIGH PRESSURE CONTINUES TO SETTLE SOUTHEAST INTO THE CNTRL
APPALACHIANS AS LOW PRESSURE TRACKS THROUGH SRN ONTARIO AND
ANOTHER LOW MOVES INTO SWRN IOWA. A COLD FRONT ASSOCIATED WITH
THE CANADIAN LOW WILL BEGIN TO PUSH SOUTH DOWN THE LENGTH OF LAKE
MICHIGAN WHILE THE OTHER SFC LOW MOVES ALONG THE IA/MO BORDER.
SHOWERS AND THUNDERSTORMS AT THE NOSE OF A LOW LEVEL JET...AT
12Z...WERE MOVING INTO WEST-CENTRAL IL. THE LATEST HIGH RES MODEL
GUIDANCE INDICATES THAT THIS LOW SHOULD TREND ON AN EVEN MORE
SOUTHERLY TRACK THAN PREVIOUSLY ANTICIPATED...INTO NERN MO BY
EARLY EVENING. WARM MOIST ADVECTION IN THE SWLY SLOW AHEAD OF THE
LOW WILL CONTINUE TO DRAW MOISTURE NEWD THROUGH IL..SETTING UP
WIDESPREAD SHOWERS AND EMBEDDED THUNDERSTORMS INTO CENTRAL IL
THROUGH THE MORNING HOURS SATURDAY...WITH SOME SHOWERS POSSIBLE
REACHING THE I-80 CORRIDOR BY ARND 18Z. WITH A MORE SOUTHERLY
TRACK TO THE SYSTEM...CHANCES FOR SHRA/TSRA MAY BE EVEN LOWER THAN
WHAT WOULD BE ASSOCIATED WITH THE VCSH GROUP...BUT WILL MAINTAIN
THIS IN THE FORECAST AS THERE IS STILL SOME CHANCE FOR SOME ISOLD
SHRA OR AN EVEN MORE ISOLD TS SNEAKING INTO THE VICINITY OF THE
CHICAGO AREA TERMINALS. ONE CHANGE TO THE GOING FORECAST WILL BE
TO INCREASE THE SUSTAINED SLWY WIND SPEEDS THIS AFTERNOON TO
10-12KT AS A BIT LESS CLOUD COVER COULD ALL FOR SOME BETTER MIXING
TO TAP THE STRONGER WINDS ALOFT. AN OCNL GUST TO 15KT IS POSSIBLE.
THE NEXT CONCERN WILL BE ASSOCIATED WITH THE COLD FRONT PUSHING
SWD THROUGH WI AND DOWN LAKE MICHIGAN. THE LATEST GUIDANCE
MAINTAINS THE IDEA THAT THE FRONT WILL NOT REACH THE CHICAGO AREA
TERMINALS UNTIL AROUND MIDNIGHT...OR SLIGHTLY LATER...AND A
LITTLE LATER FOR RFD DUE TO THE FASTER SURGE OF THE FRONT OVER THE
LAKE. WINDS SHOULD TURN NELY FOLLOWING THE FROPA AND INCREASE TO
10-15KT. NELY FLOW WILL ALSO DRAW LAKE COOLED AIR INTO NERN
IL/NWRN IN...AND CIGS/VIS SHOULD LOWER INTO LOWER END MVFR LEVELS
LATE TONIGHT OR DURG THE EARLY MORNING HOURS. THERE IS ALSO A
CHANCE CIGS COULD LOWER TO IFR LEVELS WITH A FEW SHOWERS...SO HAVE
ADDED A PROB30 GROUP TO ACCOUNT FOR THIS POTENTIAL.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE IN 9-12 KT WINDS THROUGH EARLY/MID AFTERNOON.
MEDIUM CONFIDENCE THAT RANGES OF SPEEDS WILL LOWER SLIGHTLY INTO
LATE AFTERNOON.
* MEDIUM-HIGH CONFIDENCE THAT SHRA CHANCES ARE LOW THIS AFTERNOON
AND THAT TSRA CHANCE IS MINIMAL.
MDB
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT THROUGH MONDAY...VFR. WX NIL.
MONDAY NIGHT THROUGH FRIDAY...PERIODIC CHANCES FOR SHRA/TSRA.
&&
.MARINE...
400 AM CDT
AS HIGH PRESSURE SLIDES OFF THE MID ATLANTIC COAST TODAY...LOW
PRESSURE WILL MOVE SLOWLY THROUGH THE MIDDLE MISSISSIPPI VALLEY
WHILE ANOTHER LOW OVER ONTARIO DRAGS A COLD FRONT DOWN THE LENGTH
OF LAKE MICHIGAN. A STRENGTHENING SWLY GRADIENT AHEAD OF THE COLD
FRONT WILL BRING INCREASING WINDS TO THE LAKE THROUGH THE MORNING
HOURS...APPROACHING 30 KT OVER THE NRN PORTIONS OF THE LAKE WHERE
THE GRADIENT WILL BE STRONGEST...WHILE WINDS OVER THE SRN
PORTIONS OF THE LAKE WILL STILL BE RATHER BRISK AT 15-25KT. THE
COLD FRONT WILL BEGIN TO PUSH OVER THE FAR NRN END OF THE LAKE
SHORTLY AFTER DAYBREAK AND STEADILY MOVE DOWN THE LAKE THROUGH THE
DAY TODAY. WINDS WILL QUICKLY TURN TO NLY FOLLOWING THE FROPA AND
WITH THE INITIAL SURGE OF COOLER AIR...WINDS SHOULD RAMP BACK UP
TO 30KT IMMEDIATELY FOLLOWING THE FROPA. HOWEVER...AS ANOTHER AREA
OF HIGH PRESSURE QUICKLY DROPS INTO THE THE UPPER GREAT LAKES
SATURDAY NIGHT...WINDS WILL DROP OFF WHILE VEERING TO MORE NELY.
AS THE HIGH CONTINUES TO BUILD TO THE EAST...WINDS WILL CONTINUE
TO VEER TO ELY AND THEN SELY SUNDAY NIGHT AND MONDAY. SELY WINDS
WILL THEN PERSIST ACROSS THE LAKE UNTIL MID WEEK AS ANOTHER LOW
PRESSURE SYSTEM DROPS OUT OF THE NRN PLAINS AND APPROACHES THE WRN
GREAT LAKE REGION BY LATE TUESDAY OR WEDNESDAY.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
947 AM CDT Sat Aug 16 2014
.UPDATE...
ISSUED AT 946 AM CDT SAT AUG 16 2014
Incoming area of showers and scattered storms has been showing
some fading over the last couple hours as it crosses the Illinois
River. Latest HRRR shows a narrower band of showers pushing past
the I-55 corridor midday, with some additional development
occurring to our west this afternoon near a low in southeast Iowa.
East central and southeast Illinois will see more in the way of
scattered showers through the day. Have sent some grid updates
earlier to reflect the current trends. Temperatures currently on
track and should mainly be confined to the 70s today with the
widespread cloud cover.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 323 AM CDT SAT AUG 16 2014
MCS over southern Iowa into northern Missouri early this morning
tracking slowly to the east and this feature will be our main
concern through tonight. Well out ahead of the MCS to our west, we
have had some isolated showers develop over parts of central and
east central Illinois during the past several hours. Unlike last
night at this time when we were seeing dew points in the upper 40s
to lower 50s over our northeast counties, most areas have seen the
dew points climb back well into the 60s.
Most of the short term models move the MCV associated with the
current convection out in northern Missouri/southern Iowa slowly
into southeast Iowa by late this afternoon. Current band of showers
and isolated storms will shift slowly east of the Mississippi River
by dawn this morning and continue to edge slowly east during the
morning with a gradual decrease in areal coverage as the main
support from the low level jet wanes with time early this morning.
The extensive cloud cover and showers will keep temps below guid in
most areas except the far east where the rain will not get into that
part of our forecast area until later today.
Most of the hi-resolution model solutions redevelop the convection
to the east of the MCV later this afternoon into parts of west
central Illinois and then shift the precip to the east tonight as
the vort center tracks into central IL by Sunday morning.
Precipitable water values still forecast well above 2 inches tonight
with warm cloud depths above 3km indicating some very efficient
rains with any convection that develops just to the east of the vort
center tonight. Upper winds are also forecast to weaken considerably
indicating the storms that do develop near or to the east/southeast
of the MCV will be slow movers and threaten parts of our area with
heavy rainfall. However, one negative factor for widespread heavy
rainfall will be with a much weaker low level jet than what we are
seeing out to our west tonight. Still, with the high PWAT values in
place, any storms that develop late this afternoon thru this evening
will be capable of producing high rainfall rates along and to the
east of the MCV overnight.
&&
.LONG TERM...(Sunday through Friday)
ISSUED AT 323 AM CDT SAT AUG 16 2014
Upper disturbance remaining over the FA Sunday morning in the
models. Models not really responding to the MCV equally as the low
moves out to the east. A lot of uncertainty as the day progresses,
but the better chances for the continuation of precip remain in the
east and southeast as the system tracks out to the east, just north
of the Ohio River Valley. Models dry out briefly for early Monday
morning, and chances through the day on Monday starting to drop off
a bit. Less amplified flow over the country looking messy through
the work week. Heat that has been building over the desert
southwest makes its way into the region warming up the temps to far
more of a summer pattern that has been to this point. Temps in the
upper 80s/lower 90s Wed-Friday. Weak flow aloft and a series of
small waves dipping into the Great Lakes/Midwest keeping ILX in an
unsettled weather pattern and pops dominate the extended forecast
with periodic chances for precip. Models diverge significantly
going into the weekend with the GFS building in a ridge for the
Midwest and southern Plains, while the ECMWF remains more
progressive with pushing a trof across the nrn tier of the CONUS.
Should the forecast go more the way of the GFS with subsequent
issues, the temperatures may need to be bumped up a couple degrees
under a persistent ridge. But with the ECMWF in direct opposition
and the timing of waves such a question mark...not willing to
deviate too much from what the AllBlend has in the grids just yet.
All in all, a warm forecast with periodic showers. PW values
trending down from where they were 24 hrs ago, but chances for some
of the thunderstorms to produce some heavy rain. Upper dynamics not
particularly alarming any one day just yet...but this pattern is
more reminiscent of summer than what has been around so far.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
ISSUED AT 600 AM CDT SAT AUG 16 2014
As a large area of showers and isolated thunderstorms pushes into
western Illinois this morning, we expect a gradual deterioration
in cigs and vsbys from west to east today. Rain will continue to
edge slowly east and start to affect the SPI taf area first this
morning followed by PIA with the remainder of the TAF sites seeing
the rain late this morning into the afternoon. Already seeing some
isolated showers just east of CMI, but still think the bulk of the
rain to the west may take until this afternoon to get into CMI.
Once the rain begins, cigs will drop to MVFR and even the possibility
for some brief IFR cigs/vsbys in the heavier showers. Not seeing much
in the way of lightning activity so at this point will continue to
handle it with SHRA with VCTS. As the upper level circulation works
its way into our area tonight, it appears we will see widespread
MVFR and local IFR cigs and vsbys with rain and isolated TSRA with
areas of fog. Surface winds today will be south to southeast at 8
to 15 kts with winds backing more into the east tonight as the
surface low tracks just south of the TAF sites. Wind speeds tonight
will be from 4 to 9 kts.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEELHART
SHORT TERM...SMITH
LONG TERM...HJS
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1228 PM EDT SAT AUG 16 2014
.SYNOPSIS...
ISSUED AT 1119 AM EDT SAT AUG 16 2014
THE CLOUDS WILL CONTINUE TO COVER THE REGION LEADING TO MOSTLY
CLOUDY TO CLOUDY SKIES FOR TODAY AND TONIGHT. A LOW PRESSURE
MOVING IN FROM THE WEST TO SOUTHWEST AND A COLD FRONT APPROACHING
FROM THE NORTH WILL GIVE THE REGION A CHANCE FOR SOME RAIN TODAY
AND TONIGHT. HIGH TEMPERATURES TODAY WILL BE IN THE UPPER 70S AND
LOW TEMPERATURES TONIGHT WILL RANGE FROM THE LOWER 60S IN SOUTHERN
MICHIGAN TO THE UPPER 60S NEAR THE OHIO RIVER.
&&
.UPDATE...
ISSUED AT 1215 PM EDT SAT AUG 16 2014
GRIDS WERE UPDATED EARLIER TO REFLECT NORTHERN FRINGE OF AN AREA
OF SHOWER CLIPPING PORTIONS OF JAY...BLACKFORD AND GRANT COUNTIES.
THIS WILL BE LONG GONE BY 18Z WITH ATTENTION SHIFTING BACK TO THE
WEST. 13Z HRRR WAS THE ONLY MODEL TO BE EVEN CLOSE ON LAYOUT OF
CURRENT PRECIP OVER THE AREA AND UPSTREAM. IF IT HOLDS
TRUE...WIDELY SCT SHOWERS/ISOL STORMS WILL POP ACROSS THE AREA
THIS AFTERNOON. MODELS PAST FEW DAYS HAVE ADVERTISED A RAPID
INCREASE IN LOW LEVEL MOISTURE AND THIS HAS COME TO FRUITION WITH
MANY AREAS IN THE SW BACK INTO ILLINOIS SEEING SFC DEWPOINTS JUMP
BY 10 DEGREES OR MORE JUST THIS MORNING. MOIST AIRMASS WILL REMAIN
IN PLACE UNTIL COLD FRONT...CURRENTLY DROPPING THROUGH
MICHIGAN...ENTERS THE AREA SUNDAY INTO MONDAY. SKY COVER WAS
INCREASED DRAMATICALLY WITH THE UPDATE AS LARGE SHIELD OF MID
CLOUDS WAS OVERSPREADING THE AREA. ONCE IT SETTLES IN...MOSTLY
CLOUDY TO CLOUDY SKIES SHOULD PREVAIL. LIMITED HEATING IS
OCCURRING UPSTREAM UNDER THE CLOUD CANOPY. FORECAST HIGHS MAY END
UP A TAD TOO HIGH AND WILL EVALUATE WITH NEXT GRID UPDATE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 346 AM EDT SAT AUG 16 2014
A COUPLE OF SYSTEMS WILL IMPACT THE WEATHER TODAY AND TONIGHT OVER
THE FORECAST AREA. A SURFACE LOW WAS OVER SOUTHERN IOWA WITH A VERY
MOIST FLOW OF HIGH PRECIPITABLE WATER SURGING NORTHEAST INTO A
DEVELOPING CONVECTIVE COMPLEX OVER SOUTHERN IOWA INTO NORTHERN
MISSOURI. SATELLITE CLOUD TOP TEMPERATURES WERE QUITE COLD AND WERE
STILL COOLING AS OF 3 AM EDT. THE WRF/ARW APPEARS TO BE HANDLING
THIS SYSTEM THE BEST...WHICH INCLUDES A EAST/SOUTHEAST TRACK WHICH
WILL KEEP THE BULK OF THIS SYSTEM TO THE SOUTH OF THE FORECAST AREA.
HOWEVER...LIMITED LOW LEVEL THETA E CONVERGENCE BY MID AFTERNOON
COULD BE SUFFICIENT WITH DAYTIME HEATING TO SUPPORT THUNDERSTORM
DEVELOPMENT. HAVE ELIMINATED RAIN/STORM CHANCES THIS MORNING...AND
LOWERED CHANCES THIS AFTERNOON. A COLD FRONT WILL MOVE SOUTH TODAY
AND SHOULD REACH THE NORTHERN PART OF THE FORECAST AREA BY LATE
TONIGHT. HAVE INCLUDED SOME LOW CHANCES FOR STORMS IN THE VICINITY
OF THIS FRONT. SEVERE WEATHER PARAMETERS DO NOT SUPPORT SEVERE
STORMS TODAY OR TONIGHT.
&&
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 346 AM EDT SAT AUG 16 2014
LEAD SW DISTURBANCE OVR NWRN MO THIS MORNING WILL TURN SHIFT EWD
SHRT TERM THEN SEWD TO BEGIN THIS PD IN RESPONSE TO WELL DEMARCATED
SYS SEEN IN VAPOR DIGGING THROUGH WRN/SWRN PERIPHERY OF DEEP CYCLONE
OVR SERN QB. THIS IN TURNS LEADS TO A CONTD SWD SUPPRESSION OF
AFOREMENTIONED SYS WELL SOUTH THROUGH THE OH RVR VALLEY THROUGH MON
AS SEEN ALL MODEL GUIDANCE NOW AND POSES SOME QUANDARY WRT POPS GOING
FORWARD. STG MODEL BASED CLUSTERING RECOMMENDS ERODING GOING POPS
THROUGH MON NIGHT IN ASSOCN/W THIS SYS.
MORE SIG TROUGH UPSTREAM OVR THE NRN ROCKIES FOLLOWS EWD INTO THE
NRN LAKES TUE. HWVR PER GENERAL SWD NOTED HGT SUPPRESSION ALOFT
CONCERNED THIS PD MAY BUST AS WAVY FNTL BNDRY SETS UP WELL SOUTH OF
LOCAL AREA AND WALLS OFF MORE SIG NWD LL MSTR RTN. WILL HOLD
W/TRUNCATED LOW CHC MENTION TUE-FRI IN ADHERENCE TO SURROUNDING
COLLAB YET SURMISE MUCH OF THIS PD MAY END UP DRY. BEST HOPE
PREDICATED ON GEM/EC BLEND WOULD BE TUE AFTN AND THU NIGHT.
OTRWS SIG WARMING TREND ON TAP AS BROAD UPR RIDGE EXPANDS ACRS THE
SRN US ESP LT PD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1215 PM EDT SAT AUG 16 2014
AREA OF SHOWERS WAS PASSING WELL SOUTH OF KFWA AS OF 16Z. RADAR
WAS SHOWING WIDELY SCATTERED SHOWERS TRYING TO DEVELOP ACROSS
EASTERN ILLINOIS INTO WESTERN INDIANA. STILL POTENTIAL FOR WIDELY
SCT SHOWERS...RUMBLES OF THUNDER AND BRIEF PERIOD OF MVFR
CIGS/VSBY ASSOCIATED WITH THESE. HOWEVER DURATION AND DIRECT
IMPACT AT THIS TIME TOO QUESTIONABLE TO INTRODUCE INTO TAFS.
ADDITIONAL CHANCES FOR PRECIPITATION COULD OCCUR OVERNIGHT INTO
SUNDAY PRIOR TO 18Z AS SFC LOW PASSES SOUTH OF THE AREA AND COLD
FRONT DROPS IN FROM THE NORTH. WILL MAINTAIN DRY FORECAST THROUGH
18Z FOR NOW.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
UPDATE...FISHER
SYNOPSIS...LOTHAMER
SHORT TERM...SKIPPER
LONG TERM...T
AVIATION...FISHER
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS GOODLAND KS
230 PM MDT SAT AUG 16 2014
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 230 PM MDT SAT AUG 16 2014
EARLY AFTERNOON WV IMAGERY AND RAP ANALYSIS SHOWS 595 DM RIDGE
CENTERED OVER SW US...WITH DIFFLUENT FLOW OVER THE NORTHERN PLAINS
AHEAD OF A CLOSED LOW OVER THE SOUTHERN CANADIAN ROCKIES. AT THE
SURFACE A COLD FRONT THAT MOVED INTO THE CWA LAST NIGHT ANS SHIFTED
EAST WITH WEAK CONVERGENCE ALONG A TROUGH AXIS EXTENDING ACROSS
EASTERN COLORADO.
MODERATE INSTABILITY IS IN PLACE ACROSS THE EASTERN HALF OF THE CWA
WITH ML CAPE VALUES IN THE 1000-2000 J/KG RANGE. LOWER VALUES AROUND
500 J/KG ARE IN PLACE ALONG THE TROUGH AXIS WHERE BETTER FOCUS FOR
THUNDERSTORM INITIATION IS EXPECTED. HIGHER CINH WAS EXPECTED TO
LIMIT INITIATION IN THE EAST...HOWEVER EXTENSIVE CU FIELD NOW IN
PLACE WITH BETTER VERTICAL EXTENT THAT WOULD BE EXPECTED IF AIR
MASS WAS COMPLETELY INHIBITED. WHERE THUNDERSTORMS HAVE DEVELOPED
IN THE WEST WILL REMAIN MOST LIKELY AREA FOR CONVECTION ALONG WEAK
CONVERGENCE ZONE...HOWEVER I COULDNT RULE OUT ISOLATED
THUNDERSTORM ACTIVITY FURTHER EAST WERE CAP TO WEAKEN...ESPECIALLY
WITH WESTERN EDGE OF FRONT NEAR OUR EASTERN CWA BORDER. HAVE
EXTENDED AREA OF SLIGHT CHANCE POPS AND BUMPED UP COVERAGE IN THE
SW. SEVERE THREAT REMAINS VERY LOW WITH WEAK SHEER...HOWEVER IF A
BETTER UPDRAFT WERE TO DEVELOP IN THE EAST WHERE BETTER CAPE
PROFILES EXIST THEN SEVERE HAIL/WIND COULD BE THREATS.
BETTER THUNDERSTORM COVERAGE IS EXPECTED BY MID-LATE AFTERNOON
SUNDAY AS A WEAK SHORTWAVE MOVES JUST NORTH OF THE CWA. MODELS HAVE
A DECENT PRECIP SIGNAL OVER OUR CWA...DESPITE DRY SOUNDINGS...SO
CHANCE POPS WERE RETAINED. THUNDERSTORMS WILL TEND TO BE
ELEVATED..HOWEVER EFFECTIVE SHEER AROUND 35KT AND MODERATE MU CAPE
IN THE 2000-2600 J/KG WOULD BE SUPPORTIVE OF A ELEVATED SEVERE
WIND/HAIL THREAT WITH STORMS THAT DEVELOP. WIND MAY ACTUALLY BE THE
GREATER THREAT CONSIDERING THE INVERTED V PROFILES IN PLACE.
SOUTHERLY FLOW SHOULD BRING GOOD WAA BACK TO THE CWA...AND TEMPS
SHOULD BE AS WARM IF NOT WARMER AS TODAY WITH VALUES IN THE MID-
UPPER 90S.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 230 PM MDT SAT AUG 16 2014
A PERSISTENT UPPER LEVEL PATTERN WILL REMAIN DRAPED ACROSS THE
FORECAST AREA THROUGHOUT THE EXTENDED FORECAST PERIOD. THIS MEANS A
CONTINUATION OF THE ABOVE NORMAL TEMPERATURES AND THUNDERSTORM
CHANCES EACH AFTERNOON.
FOR SUNDAY NIGHT...A STRONG SHORTWAVE WILL PROGRESS ACROSS THE
NORTHERN GREAT PLAINS. SOME ENERGY SHOULD PASS OVER THE TRI-STATE
REGION...LEADING SCATTERED THUNDERSTORMS. WITH THIS DISTURBANCE AND
ASSOCIATED STRONGER WINDS MOVING THROUGH...THERE IS AN INCREASE IN
WIND SHEAR. WITH ATMOSPHERE INSTABILITY/CAPE UP TO 2000-2500
J/KG...THERE COULD BE A MORE ORGANIZED THREAT FOR SEVERE
WEATHER...ESPECIALLY EAST OF THE COLORADO BORDER. LARGE HAIL AND
DAMAGING WINDS WOULD BE THE MAIN THREATS AS BOUNDARY LAYER MOISTURE
IS NOT SUPPORTIVE OF A TORNADIC ENVIRONMENT. MOST OF THE
THUNDERSTORM ACTIVITY SHOULD LEAVE THE AREA BY MIDNIGHT AS THIS WILL
BE A FAST MOVING SHORTWAVE.
FOR MONDAY AFTERNOON/EVENING AND TUESDAY AFTERNOON/EVENING...
ADDITIONAL UPPER DISTURBANCES LEAD TO CONTINUED CHANCES FOR
STRONG/SEVERE THUNDERSTORMS. TUESDAY APPEARS HAVE A SLIGHTLY BETTER
CHANCE OF CONVECTIVE ACTIVITY AS THERE ARE SOME QUESTIONS ABOUT
ATMOSPHERE INSTABILITY MONDAY AND THE EFFECT THAT SUNDAY NIGHTS
CONVECTION WOULD HAVE ON THE ENVIRONMENT. LARGE HAIL AND DAMAGING
WINDS ARE ONCE AGAIN THE PRIMARY THREATS.
FOR WEDNESDAY AND BEYOND...DISAGREEMENT WITHIN THE MODEL GUIDANCE
LEADS TO LOWER CONFIDENCE IN THE TIMING AND LOCATIONS FOR BEST
THUNDERSTORM CHANCES. THERE COULD BE STORMS EACH DAY WITH THE
STAGNANT PATTERN AND CONTINUED UPPER LEVEL DISTURBANCE PASSAGES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1120 AM MDT SAT AUG 16 2014
VFR CONDITIONS SHOULD PREVAIL AT BOTH KGLD AND KMCK TERMINALS
THROUGH THE TAF PERIOD. LIGHT FOG WITH VIS AROUND 6SM (MAYBE LESS)
WILL BE POSSIBLE AT KMCK...SIMILAR TO WHAT OCCURRED THIS MORNING.
THERE ISNT A STRONG SIGNAL IN GUIDANCE FOR THIS...SO HAVE LIMITED
MENTION TO 6SM GROUP AT 11-15Z. WITH WEAK SURFACE PRESSURE
GRADIENT OVER BOTH TERMINALS WINDS WILL REMAIN ERRATIC THROUGH THE
PERIOD...GENERALLY 6KT OR LESS. EVENTUALLY WINDS SHOULD SHIFT TO
MORE OF A SOUTHEAST DIRECTION LATE IN THE TAF PERIOD...AGAIN
AROUND 6KT.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...RRH
AVIATION...DR
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
408 PM EDT SAT AUG 16 2014
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 407 PM EDT SAT AUG 16 2014
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL LOW OVER
QUEBEC WITH NW FLOW IN ITS WAKE THROUGH THE NRN GREAT LAKES.
AT THE SFC...THE COLD FRONT HAS DROPPED SOUTH OF UPPER MI AS HIGH
PRES OVER NRN MANITOBA INTO NW ONTARIO BUILDS SOUTHWARD. ALTHOUGH
STRONG MID LEVEL DRYING HAD TAKEN OVER IN THE WAKE OF THE SHRTWV
THAT MOVED THROUGH EARLY TODAY...ABUNDANT LOW LEVEL MOISTURE AND
NRLY FLOW SUSTAINED OVC SKIES OVER MOST OF NRN UPPER MI. DOWNSLOPE
FLOW AND DAYTIME MIXING HAS BROUGHT MORE CLEARING TO SRN UPPER MI.
TONIGHT...HIGH PRES WILL BUILD FROM NRN ONTARIO THROUGH THE NRN
GREAT LAKES. CLOUDS SHOULD CONTINUE TO DIMINISH THIS EVENING BUT
WILL BE BE DELAYED WHERE ONSHORE/UPSLOPE NE WINDS PREVAIL...PER
UPSTREAM/SATELLITE TRENDS AND NAM/RUC 925-900 MB RH FCST. WITH
ENOUGH CLEARING MIN READINGS WILL FALL INTO THE MID 40S INLAND BUT
WHERE THICKER CLOUDS PERSIST...LOWS WILL ONLY DROP INTO THE LOWER
50S.
SUNDAY...AS THE RIDGE BUILDS OVER THE AREA...EXPECT THAT THE
COMBINATION OF DRY ADVECTION AND MIXING BY AFTERNOON WILL FINALLY
SCOUR OUT THE REMAINING OVERCAST WITH MAINLY JUST SCT/BKN CU INLAND.
TEMPS WILL CLIMB BACK INTO EH UPPER 50S AND LOWER 70S BUT REMAIN IN
THE LOWER 60S WHERE ENE ONSHORE FLOW PREVAILS NEAR LAKE SUPERIOR.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 335 PM EDT SAT AUG 16 2014
MAIN FCST CONCERNS IN THE LONGER TERM WL FOCUS ON HOW QUICKLY SHRTWV
NOW TRACKING THRU THE NRN ROCKIES AND ACCOMPANYING DEEPER MSTR WL
ARRIVE AND IMPACT POPS INTO MID WEEK UNDER BLDG UPR RDG.
SUN NGT/MON...SFC HI PRES JUST S OF JAMES BAY UNDER RDG AXIS ACRS NW
ONTARIO AT 12Z MON WL DOMINATE AND BRING DRY WX THRU AT LEAST MOST
OF SUN NGT. BUT A GOOD NUMBER OF THE MORE RECENT MODELS HAVE TRENDED
FASTER ON SHIFTING THE REMNANT OF THE CLOSED LO TRACKING THRU THE
NRN ROCKIES/ASSOCIATED MSTR UNDER WAD IN ADVANCE OF THIS DISTURBANCE
TO THE E AND TOWARD THE UPR LKS ON MON. SO HAVE INCREASED CLD COVER
AND BROUGHT POPS TO THE E FASTER THAN SHOWN ON THE PREVIOUS FCST...
WITH CHC POPS OVER THE W BY 12Z MON AND ACROSS ALL BUT THE E ON MON
AFTN AS PWAT IS FCST TO INCRS TO 1.50 TO 1.75 INCHES UNDER FALLING
HGTS/DIFFLUENT UPR FLOW/DPVA/DEEP LYR QVECTOR CNVGC TO THE E OF THE
APRCHG SHRTWV. CONSIDERING THE FASTER ARRIVAL OF THE MSTR/STRONGER
SLY FLOW FM THE W...BUMPED UP FCST MIN TEMPS OVER THE W ON SUN NGT.
BUT LOWERED FCST TEMPS OVER THE INTERIOR E CLOSER TO THE DEPARTING
SFC HI/DRIER AIR WITH PWAT UNDER 0.75 INCH/LIGHTER WINDS. WITH AN
EARLIER ARRIVAL OF MORE CLDS ON MON...OPTED TO LOWER FCST HI TEMPS A
BIT DESPITE FCST H85 TEMPS UP TO 14-15C OVER THE W.
MON NGT INTO WED...WHILE MEAN UPR RDG IS FCST TO BUILD ACROSS ERN
NAMERICA DOWNSTREAM OF DEEPENING TROF OVER THE W...SHRTWV APRCHG FM
THE W WL DRIFT SLOWLY THRU THE GREAT LKS. UNDER POCKET OF COOLER H5
TEMPS/HIER PWAT UP TO 1.50-1.75 INCHES...THERE WL BE AT LEAST SOME
SCT SHOWERS/A FEW TS ARND DURING THIS PERIOD. THE PROBABILITY OF
THESE SHOWERS WL BE GREATEST DURING DAYTIME HEATING ON TUE AFTN/
EVNG. A GOOD DEAL OF CLD COVER WL RESTRICT THE DIURNAL TEMP
RANGE...WITH HI TEMPS NOT FAR FM 70 RUNNING BLO NORMAL BUT MRNG LO
TEMPS MAINLY 55 TO 60 ABV AVG. IF THE UPR LO EXITS FASTER ON WED...
MORE AFTN SUNSHINE MIGHT ALLOW FOR WARMER TEMPS THEN.
END OF THE WEEK...AS THE SHRTWV MOVING THRU THE LKS SHIFTS AWAY
LATER WED AND HGTS RISE...EXPECT A DRYING TREND FOR WED NGT INTO
THU. SOME OF THE LONGER RANGE GUIDANCE HINTS ANOTHER SHRTWV RIDING
ENEWD THRU THE UPR MS RIVER VALLEY AND TOWARD NW ONTARIO/THE UPR LKS
MAY BRING MORE SHOWERS/A FEW TS TO THE AREA LATER ON THU INTO FRI.
VARIOUS MODELS INDICATE THIS SHRTWV WL BE SLOWER AND NOT IMPACT THE
AREA UNTIL SAT. CONSIDERING THE UNCERTAINTY ON SPECIFICS THIS FAR
OUT IN THE FCST PERIOD...WL RELY ON EXTENDED MODEL CONSENSUS FOR
FCST GENERATION. OVERALL TEMPS SHOULD RUN AOA NORMAL IN THE PRESENCE
OF MEAN UPR RDG TO THE E OF LARGER SCALE WRN TROF.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 139 PM EDT SAT AUG 16 2014
LOW CLOUDS WITH IFR/MVFR CIGS AT SAW/CMX ARE EXPECTED TO GIVE WAY TO
SOME IMPROVEMENT BY LATE AFTERNOON AS DAYTIME MIXING AND WEAK DRY
ADVECTION STRENGTHEN. HOWEVER...PERSISTENT MOIST UPSLOPE FLOW AT SAW
WILL DELAY ANY CLEARING UNTIL LATER THIS EVENING. THE VFR CONDITIONS
AT SAW MAY BE BRIEF AS CONTINUED MOIST NE FLOW STRENGTHENS LEADING TO
MVFR CONDITIONS. THE NE OR ENE FLOW WILL BE LESS FAVORABLE FOR LOWER
CLOUDS AT CMX OR IWD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 335 PM EDT SAT AUG 16 2014
EXPECT WINDS UNDER 20 KTS OVER THE NEXT WEEK AS A RELATIVELY WEAK
PRESSURE GRADIENT DOMINATES THE UPPER GREAT LAKES ABOVE THE CHILLY
WATERS OF LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KC
AVIATION...JLB
MARINE...KC
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
600 PM CDT SAT AUG 16 2014
.SHORT TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 248 PM CDT SAT AUG 16 2014
THE AREA REMAINS IN BETWEEN TWO UPPER SYSTEMS WITH ONE WELL TO OUR
NORTH AND ANOTHER TO OUR EAST. CONVECTION COULD STILL DEVELOP IN
NORTHEAST NEBRASKA ON THE FAR SOUTHERN EXTENT OF THE NORTHERN
SYSTEM...WITHIN A SLIGHTLY AGITATED CU FIELD BETWEEN KBVN...KONL
AND KYKN...AS SUGGESTED BY THE HRRR MODEL. ANY ANYTHING INDEED
DEVELOPS EARLY THIS EVENING...IT WOULD PROBABLY DIMINISH/END BY
MIDNIGHT...ALTHOUGH THE NAM WOULD HOLD IT TOGETHER ACROSS EASTERN
NEBRASKA THROUGH THE WEE HOURS.
FOCUS THEN SHIFTS TO FOG REDEVELOPMENT OVERNIGHT AS AMPLE LOW
LEVEL MOISTURE REMAINS WITH SURFACE DEWPOINTS IN THE UPPER 60S TO
LOWER 70S. WINDS WILL LIKELY GO CALM IN MANY PLACES OVERNIGHT.
MET/MAV/LAV GUIDANCE ALL INDICATES FOG WILL REDEVELOP BY 06Z...AND
COULD BECOME LOCALLY DENSE BY 09-11Z...THEN LIFTING/BURNING OFF BY
14-15Z. HAVE ADDED PATCHY DENSE FOG INTO THE GRIDS...AND MAY HAVE
TO EVENTUALLY ISSUE A DENSE FOG ADVISORY FOR PARTS OF THE REGION
TONIGHT AS CONDITIONS MATERIALIZE. AREAS MOST SUSCEPTIBLE INCLUDE
ALL OF WESTERN IOWA...THE THE PLATTE AND MISSOURI RIVER VALLEYS.
CONVECTIVE DEVELOPMENT SUNDAY IS ALSO QUESTIONABLE...BUT THE
LINGERING VERY SUBTLE TROUGH WITH ASSOCIATED ACTIVITY THIS
EVENING COULD BE ALONG THE MISSOURI RIVER SUNDAY AFTERNOON...THUS
WILL MAINTAIN JUST 20 PERCENT CHANCE OF STORMS ALONG/EAST OF THE
MISSOURI RIVER THROUGH PEAK HEATING TOMORROW.
SHOULD BE ANOTHER DRY PERIOD SUNDAY EVENING...BUT CONVECTION
CHANCES INCREASE AGAIN BY DAYBREAK MONDAY AS THE NEXT IMPULSE
BEGINS TO MOVE INTO THE AREA FROM THE HIGH PLAINS. RAIN CHANCES
CONTINUE MONDAY...AND MAY LINGER FOR SOUTHEAST NEBRASKA MONDAY
NIGHT...BUT SHOULD BE DRY AGAIN FOR TUESDAY.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 248 PM CDT SAT AUG 16 2014
ANOTHER SLOW MOVING WAVE MOVES INTO THE REGION TUESDAY NIGHT
THROUGH WEDNESDAY NIGHT BRINGING ONE MORE CHANCE OF STORMS TO THE
AREA. RIDGING THEN BUILDS BACK ACROSS THE PLAINS FOR THE END OF
THE WEEK WITH DRY WEATHER...AND TEMPS WARMING INTO THE LOWER 90S
AGAIN. COULD SEE A NOCTURNAL CHANCE OF STORMS UNDERNEATH THE RIDGE
FRIDAY NIGHT.
&&
.AVIATION...(00Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 600 PM CDT SAT AUG 16 2014
LOOK FOR DETERIORATING CONDITIONS OVERNIGHT WITH FOG DEVELOPING.
ISOLD TSRA COULD AFFECT KOFK FOR A FEW HOURS THIS EVENING. FOR
NOW...WE DO NOT EXPECT THIS ACTIVITY TO MAKE IT TO KOMA OR KLNK.
WINDS WILL BE LIGHT AND WITH PLENTY OF LOW LEVEL MOISTURE IN PLACE
WE SHOULD SEE IFR CONDITIONS DEVELOP LATER TONIGHT...MAINLY AFTER
09Z. THE FOG SHOULD GRADUALLY LIFT/BREAK UP BY MID MORNING SUNDAY
LEAVING MAINLY VFR CONDITIONS FOR THE REST OF THE MORNING AND
AFTERNOON.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...DEWALD
LONG TERM...DEWALD
AVIATION...MILLER
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
303 PM CDT SAT AUG 16 2014
.SHORT TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 248 PM CDT SAT AUG 16 2014
THE AREA REMAINS IN BETWEEN TWO UPPER SYSTEMS WITH ONE WELL TO OUR
NORTH AND ANOTHER TO OUR EAST. CONVECTION COULD STILL DEVELOP IN
NORTHEAST NEBRASKA ON THE FAR SOUTHERN EXTENT OF THE NORTHERN
SYSTEM...WITHIN A SLIGHTLY AGITATED CU FIELD BETWEEN KBVN...KONL
AND KYKN...AS SUGGESTED BY THE HRRR MODEL. ANY ANYTHING INDEED
DEVELOPS EARLY THIS EVENING...IT WOULD PROBABLY DIMINISH/END BY
MIDNIGHT...ALTHOUGH THE NAM WOULD HOLD IT TOGETHER ACROSS EASTERN
NEBRASKA THROUGH THE WEE HOURS.
FOCUS THEN SHIFTS TO FOG REDEVELOPMENT OVERNIGHT AS AMPLE LOW
LEVEL MOISTURE REMAINS WITH SURFACE DEWPOINTS IN THE UPPER 60S TO
LOWER 70S. WINDS WILL LIKELY GO CALM IN MANY PLACES OVERNIGHT.
MET/MAV/LAV GUIDANCE ALL INDICATES FOG WILL REDEVELOP BY 06Z...AND
COULD BECOME LOCALLY DENSE BY 09-11Z...THEN LIFTING/BURNING OFF BY
14-15Z. HAVE ADDED PATCHY DENSE FOG INTO THE GRIDS...AND MAY HAVE
TO EVENTUALLY ISSUE A DENSE FOG ADVISORY FOR PARTS OF THE REGION
TONIGHT AS CONDITIONS MATERIALIZE. AREAS MOST SUSCEPTIBLE INCLUDE
ALL OF WESTERN IOWA...THE THE PLATTE AND MISSOURI RIVER VALLEYS.
CONVECTIVE DEVELOPMENT SUNDAY IS ALSO QUESTIONABLE...BUT THE
LINGERING VERY SUBTLE TROUGH WITH ASSOCIATED ACTIVITY THIS
EVENING COULD BE ALONG THE MISSOURI RIVER SUNDAY AFTERNOON...THUS
WILL MAINTAIN JUST 20 PERCENT CHANCE OF STORMS ALONG/EAST OF THE
MISSOURI RIVER THROUGH PEAK HEATING TOMORROW.
SHOULD BE ANOTHER DRY PERIOD SUNDAY EVENING...BUT CONVECTION
CHANCES INCREASE AGAIN BY DAYBREAK MONDAY AS THE NEXT IMPULSE
BEGINS TO MOVE INTO THE AREA FROM THE HIGH PLAINS. RAIN CHANCES
CONTINUE MONDAY...AND MAY LINGER FOR SOUTHEAST NEBRASKA MONDAY
NIGHT...BUT SHOULD BE DRY AGAIN FOR TUESDAY.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 248 PM CDT SAT AUG 16 2014
ANOTHER SLOW MOVING WAVE MOVES INTO THE REGION TUESDAY NIGHT
THROUGH WEDNESDAY NIGHT BRINGING ONE MORE CHANCE OF STORMS TO THE
AREA. RIDGING THEN BUILDS BACK ACROSS THE PLAINS FOR THE END OF
THE WEEK WITH DRY WEATHER...AND TEMPS WARMING INTO THE LOWER 90S
AGAIN. COULD SEE A NOCTURNAL CHANCE OF STORMS UNDERNEATH THE RIDGE
FRIDAY NIGHT.
&&
.AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1249 PM CDT SAT AUG 16 2014
LINGERING MOISTURE AND HEATING TO RESULT CLOUDS AND MVFR/VFR
CONDITIONS FL025-050. A FEW ISOLATED SHOWERS/STORMS MAY TRY TO
DEVELOP...ESPECIALLY TOWARD KOFK...RELATED TO A SHORTWAVE PASSING
TO THE NORTH AND LOW LEVEL CONVERGENCE. DUE TO THE ISOLATED
NATURE...WILL NOT MENTION AT THIS TIME. LATER TONIGHT...LOW LEVEL
MOISTURE REMAINS IN PLACE AND LOW LEVEL FLOW IS WEAK. FOG...DENSE
AT TIMES SHOULD RE-DEVELOP AND MENTION ESPECIALLY BETWEEN 09Z-15Z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...DEWALD
LONG TERM...DEWALD
AVIATION...ZAPOTOCNY
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
128 PM EDT SAT AUG 16 2014
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND OVER THE AREA FROM OFFSHORE THROUGH
EARLY NEXT WEEK WITH A TROUGH OF LOW PRESSURE INLAND. A WEAK COLD
FRONT WILL MOVE IN FROM THE NORTH TUESDAY NIGHT...THEN RETURN
NORTH WEDNESDAY.
&&
.NEAR TERM /REST OF TODAY/...
AS OF 130 PM SATURDAY...HEAVY SHOWERS AND SOME RUMBLES OF THUNDER
HAVE QUICKLY DEVELOPED ACROSS WILMINGTON`S AREA AS A SHORTWAVE GETS
HUNG UP ALONG THE SC/NC BORDER. THIS ACTIVITY COULD SHIFT
NORTHWARD WITH ADDITIONAL CONVECTION EXPECTED TO DEVELOP THIS
AFTERNOON. INCREASED TO CHC SHOWER/THUNDERSTORM ACROSS OUR SW
SECTOR TO ACCOUNT FOR THE ONGOING DEV ELOPEMENT. TEMP TRENDS LOOK
GOOD AS WE GET INTO THE UPPER 80S INLAND TO MID 80S ALONG THE
COAST. LOCATIONS TO THE SOUTH AND WEST WILL HAVE A BIT MORE CLOUD
COVER KEEPING TEMPS A DEGREE OR TWO LOWER.
/PREVIOUS DISCUSSION/
AS OF 400 AM SATURDAY...ISOLATED SHOWER/TSTM THREAT WILL CONTINUE
ACROSS NRN HALF OF AREA THROUGH 8 AM AS ADDITIONAL ACTIVITY
DEVELOPING SOUTH OF MAIN AREA NEAR NC/VA LINE. HRRR HAS GOOD
HANDLE ON THIS ACTIVITY. ISOLATED THREAT PSBL OVER NE SECTIONS 8
AM TIL NOON AND CONTINUED PREVIOUS FCST 20 POP THERE. SHRT WV
ENERGY...HEATING...INLAND TROF AND SEA BREEZE SUPPORT ISOLATED
SHOWERS/TSTMS INLAND OF COAST THIS AFTN. HIGH TEMPS AROUND 90
INLAND WITH MID 80S OBX.
&&
.SHORT TERM /TONIGHT/...
AS OF 400 AM SATURDAY...ISOLATED CONVECTIVE THREAT WILL CONTINUE
INLAND THIS EVENING...WITH ANOTHER SHRT WV MOVING IN FROM W-NW.
MODELS SUPPORT ACTIVITY DIMINISHING OVERNIGHT...BUT SOME
REDEVELOPMENT PSBL ALONG COAST NEAR MORNING...THUS NO CHANGE TO
PREVIOUS FCST. MIN TEMPS FROM AROUND 70 INLAND TO MID 70S COAST.
&&
.LONG TERM /SUNDAY THROUGH SATURDAY/...
AS OF 330 AM SAT...LONG TERM PERIOD WILL BE DOMINATED BY WARMING
TEMPERATURE PATTERN WITH OCCASIONAL BOUTS OF SHOWERS AND
THUNDERSTORMS.
LOW LEVEL SFC FLOW RETURNS TO THE AREA THIS WEEKEND WITH INCREASING
TEMPS...THOUGH DEWPOINTS WILL BE A BIT SLOWER TO RESPOND SO STILL
EXPECTING NEAR CLIMO LOWS OVERNIGHT. CONTINUED TYPICAL SUMMERY
PATTERN ON SUNDAY WITH ISOLATED AFTERNOON THUNDERSHOWERS ALONG SEA
BREEZE FRONT.
MED/LONG RANGE MODELS IN FAIRLY GOOD AGREEMENT WITH RESPECT TO
SYNOPTIC REGIME THROUGH THE LONG TERM...WITH SLOWLY BUILDING HEIGHTS
AS MID ATLANTIC RIDGE BUILDS INTO THE DEEP SOUTH. THIS WILL BRING
HOT TEMPS AND HIGH HUMIDITY VALS AS LAYER MIX RATIOS INC TO AROUND
16 G/KG EARLY TO MID NEXT WEEK. THE REGION LOOKS TO REMAIN JUST
SOUTH OF THE STORM TRACK...THOUGH COULD BE AFFECTED BY A SYSTEM
EXPECTED TO TRAVERSE THE MID ATLANTIC REGION IN THE MON NIGHT TO TUE
TIME FRAME AND THEN AGAIN MID TO LATE WEEK.
FOR MONDAY AFTERNOON AND EVENING...HAVE AN INCREASING POP TREND AS
MODEL SUITE IS IN GOOD AGREEMENT ON A COMPACT SHORTWAVE TRAVERSING
THE MID ATLANTIC STATES...WITH SFC REFLECTION NOTED ACROSS THE
DELMARVA PENINSULA MON NIGHT. TRICKY TO PIN DOWN WHERE/WHEN
DEVELOPMENT WILL TAKE PLACE IN THIS CONVECTIVE REGIME...SO HAVE
CAPPED POPS IN THE CHANCE RANGE...LOWEST ACROSS THE SOUTHERN FA.
POTENTIAL MCS ACTIVITY COULD BRING A GOOD AMOUNT OF QPF TO PARTS OF
E NC THROUGH MON NIGHT. IN ADDITION...LAYER MIX RATIOS INC QUITE A
BIT INTO THE 17 G/KG RANGE WITH PWATS AROUND 2 INCHES. THE LOW MOVES
OFFSHORE ON TUE WITH ATTENDANT TRAILING COLD FRONT PUSHING INTO THE
AREA. KEPT CHANCE POPS TUE AS ANOTHER ROUND OF SHOWERS/STORMS COULD
AFFECT THE AREA AHEAD OF THE FRONT.
WED WILL MOST LIKELY BE A DRY DAY AS SUBSIDENCE TAKES PLACE BEHIND
EXITING LOW/SHORTWAVE BUT HAVE KEPT SLIGHT CHANCE POPS IN FCST AS
THERE IS STILL INSTABILITY PRESENT DUE TO A WARM AND MUGGY AIRMASS
IN PLACE.
THUR INTO NEXT WEEKEND...RIDGE BUILDS ACROSS THE CENTRAL CONUS
ALLOWING FOR UPR FLOW TO BECOME MORE NW ACROSS THE EASTERN SEABOARD.
THIS WILL BRING BOUTS OF NW FLOW CONVECTION WITH H85 MB BAROCLINIC
ZONE LOCATED IN THE VCNTY. HAVE PAINTED LOW CHANCE POPS FOR THIS
PERIOD AS OCNL SHORTWAVE ACTIVITY WILL AFFECT THE AREA.
TEMPS DURING THE PERIOD WILL BE QUITE WARM AND ABOVE CLIMO...WITH
THICKNESSES SUGGESTING HIGHS IN THE LOW TO OCNL MID 90S PERHAPS AT
TIMES. LOWS WILL BE MUGGY IN THE 70S.
&&
.AVIATION /18Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM /THROUGH 18Z SUNDAY/...
AS OF 130 PM SATURDAY...VFR CONDITIONS EXPECTED THROUGH MUCH OF
THE PERIOD. HOWEVER...ANTICIPATING SCHC SHOWER/THUNDERSTORM
ACTIVITY THIS AFTERNOON. ANY DEVELOPMENT AT OR NEAR TAF SITES WILL
LIKELY REDUCE VSBYS/LOWER CIGS TO SUB-VFR CRITERIA. AT THIS
POINT...FEEL THE DEVELOPMENT WILL BE WIDESPREAD IN COVERAGE. SO
HAVE ALL TAF SITES UNDER A VCTS THROUGH 01Z. NOT CONFIDENCE ENOUGH
IN EXACT LOCATION FORMATION TO PUT TEMPO GROUPS IN JUST YET.
CLOUDS/CONVECTIVE DEBRIS WILL DISSIPATE THROUGH THE EVENING HOURS
WITH SOME HIGH CLOUDS MOVING INTO THE AREA UNDER LIGHT SOUTHERLY
FLOW. PATCHY FOG IS POSSIBLE OVERNIGHT. WITH A BETTER INFLUX OF
LOW LEVEL MOISTURE...CALM WINDS AND ENOUGH CLEARING TAF SITES MAY
GET A BRIEF PERIOD OF MVFR FOG. CLOUDS WILL BE ON THE INCREASE
THROUGH SUNDAY AS A SHORTWAVE APPROACHES THE REGION. SCHC
SHOWER/THUNDERSTORM ACTIVITY AGAIN SUNDAY AFTERNOON UNDER
CONTINUAL SOUTHERLY FLOW.
LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 330 AM SAT...GENERALLY EXPECT VFR CONDITIONS WITH ONLY
OCCASIONAL PERIODS OF SHOWERS/STORMS PRODUCING MVFR CONDITIONS
THROUGH THE LONG TERM PERIOD. MAY BE SOME LIGHT FOG/STRATUS EACH
NIGHT IN THE LONG TERM AS WINDS WILL BE LIGHT TO CALM EACH EVENING.
&&
.MARINE...
SHORT TERM /THROUGH TONIGHT/...
AS OF 130 PM SATURDAY...FORECAST LOOKS GOOD. NO CHANGES NEEDED.
SEAS 1 TO 2 FEET AND SW FLOW AROUND 5-15KTS.
/PREVIOUS DISCUSSION/
AS OF 400 AM SATURDAY...PRES GRADIENT BETWEEN INLAND TROF AND
OFFSHORE HIGH PRESSURE WILL TIGHTEN SLIGHTLY WITH HEATING
TODAY...RESULTING IN S-SW WINDS INCREASING TO 10-15 KT THIS AFTN
AND GRADUALLY DIMINISH OVERNIGHT. SEAS GENERALLY REMAINING AROUND
2 FT.
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 330 AM SAT...THE PERIOD BEGINS WITH SOUTH TO SW FLOW THAT INC
A BIT ON SUN AS GRADIENT INC. IN GENERAL FLOW WILL REMAIN SOUTHERLY
INCREASING TO AROUND 15 KT SUNDAY AFTERNOON THROUGH SUNDAY NIGHT.
COULD SEE A FEW 4 FOOT SEAS IN THE OUTER WATERS IN THIS TIME FRAME.
MONDAY AFTERNOON INTO TUE THE GRADIENT WILL TIGHTEN FURTHER AS AN
AREA OF LOW PRESSURE TRACKS TO OUR NORTH WITH S TO SW FLOW
INCREASING TO 15 TO 20 KT AHEAD OF A TRAILING COLD FRONT. THIS WILL
ALLOW SEAS TO BUILD TO 4 TO 5 FEET ACROSS CENTRAL AND SOUTHERN OUTER
WATERS. THE COLD FRONT PASSES THROUGH THE WATERS TUE NIGHT AND
DISSIPATES BRINGING LIGHTER WINDS RETURNING TO SOUTHERLY BY LATE
WEDNESDAY AND SEAS RETURNING TO 2 TO 3 FEET. SOME DISAGREEMENT
TOWARDS THE END OF NEXT WEEK AS GFS BRINGS GUSTY NE WINDS TO THE
AREA...HOWEVER MORE LIKELY SCENARIO IS FOR WINDS TO REMAIN S TO SW
AS HIGH PRES REMAINS IN CONTROL OF THE SE SEABOARD AND CONDITIONS TO
REMAIN SUB SCA.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JBM
NEAR TERM...JBM/LEP
SHORT TERM...JBM
LONG TERM...TL
AVIATION...LEP
MARINE...JBM/TL/LEP
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1242 PM CDT SAT AUG 16 2014
.UPDATE...
ISSUED AT 1241 PM CDT SAT AUG 16 2014
THE 12 UTC DETERMINISTIC SUITE IS MUCH LESS ROBUST WITH CONVECTION
RE-DEVELOPING ACROSS WESTERN AND SOUTH CENTRAL NORTH DAKOTA THIS
AFTERNOON THROUGH TONIGHT...THUS...CUT BACK POPS FOR THESE AREAS.
TEH FOCUS FOR HEAVY RAIN THE REMAINDER OF THE AFTERNOON WILL BE
MOVING INTO THE SOUTHERN JAMES RIVER VALLEY WHERE SUNSHINE HAS
ALLOWED TEMPERATURES TO CLIMB TO NEAR 80F WITH DEW POINTS IN THE
LOWER 70S.
UPDATE ISSUED AT 915 AM CDT SAT AUG 16 2014
GIVEN RADAR TRENDS THROUGH 14 UTC...THE 10-11 UTC HRRR ITERATIONS
AND 00 UTC WRF-ARW/NMM SOLUTIONS...THE FOCUS FOR HEAVY RAINFALL
THIS MORNING AND AFTERNOON WILL BE ACROSS THE PRAIRIE POT HOLE
REGION OF SOUTH CENTRAL NORTH DAKOTA...SHIFTING INTO THE JAMES
RIVER VALLEY IN THE SOUTHEAST QUADRANT OF THE MESO-LOW EVIDENT ON
RADAR ACROSS THE HIGHWAY 83 CORRIDOR THIS MORNING. FLASH FLOOD
GUIDANCE IS IN THE 2-3 INCH PER HOUR RANGE FOR THESE AREAS.
ACROSS THE WEST...ESPECIALLY FOR THOSE AREAS WHICH WERE IMPACTED
BY VERY HEAVY RAIN OVER THE PAST 24-36 HOURS...MUCH OF THE DAY
WILL BE RATHER PRECIPITATION FREE. THE MAIN CONCERN IS FOR THIS
EVENING AND TONIGHT AS ANOTHER ROUND OF THUNDERSTORMS IS FORECAST
TO PROPAGATE INTO THE AREA FROM EASTERN MONTANA AS UPPER LEVEL
FORCING INCREASES AHEAD OF THE UPPER LEVEL LOW ACROSS THE NORTHERN
ROCKIES. FLASH FLOOD GUIDANCE IS WELL BELOW ONE INCH FOR MOST AREAS
ALREADY IMPACTED BY HEAVY RAIN...WITH ANY ADDITIONAL RAINFALL
AGGRAVATING THE ONGOING FLOODING.
UPDATE ISSUED AT 625 AM CDT SAT AUG 16 2014
BROAD AREA OF PRECIP CONTINUES TO STRETCH FROM NORTHWESTERN TO
SOUTH CENTRAL NORTH DAKOTA. GOING FORECAST ADDRESSES THIS WELL.
ONLY CHANGES MADE WERE TO PULL AREAS OF FOG FURTHER NORTH AND
WEST TO MATCH CURRENT OBS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CDT SAT AUG 16 2014
ISSUES IN THE SHORT TERM ARE ALL HYDROLOGIC WHICH IS BEING
FOCUSED ON IN THIS SHORT TERM SECTION.
LATEST RADAR TRENDS ARE FINALLY SHOWING A SLIGHT EASTWARD PUSH TO
THE LARGE AREA OF HEAVY RAIN OVER THE CENTRAL PART OF WESTERN
NORTH DAKOTA. THIS WILL BE WELCOME NEWS TO THE FOLKS IN DUNN
COUNTY WHERE SIGNIFICANT OVERLAND FLOODING WAS OCCURRING. THE
FLOOD WARNING CONTINUES FOR THAT CENTRAL PART OF WESTERN NORTH
DAKOTA THROUGH THE DAY SATURDAY. AS THE BACK EDGE OF THE RAIN AREA
WAS SHOWING A SLIGHT PUSH TO THE EAST...THE EASTERN EDGE OF THE
RAIN WAS ADVANCING MORE QUICKLY THROUGH MCLEAN AND MERCER
COUNTIES. AT THE SAME TIME NEW SHOWER/STORM DEVELOPMENT WAS
OCCURRING IN THE MANDAN-BISMARCK-STEELE AREAS.
DIFFLUENT FLOW ALOFT CONTINUES TODAY WITH SHORT WAVE ENERGY
ROTATING AROUND THE MAIN CLOSED H5 LOW IN SOUTHERN ALBERTA CANADA.
THIS MEANS A CONTINUED HIGH CHANCE FOR RAIN ACROSS THE WESTERN AND
CENTRAL PARTS OF THE FORECAST AREA INTO THIS AFTERNOON...SHIFTING
EAST BY LATE DAY.
OVERLAND FLOOD WARNING CONTINUES FOR MCKENZIE...DUNN...GOLDEN VALLEY...
BILLINGS...STARK...AND WESTERN MERCER AND WESTERN MORTON COUNTIES
THROUGH THE AFTERNOON.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 345 AM CDT SAT AUG 16 2014
MAIN CHALLENGE FOR THE EXTENDED IS CONTINUED PRECIPITATION CHANCES
TO START THE UPCOMING WEEK. CENTER OF UPPER LOW WILL PUSH ACROSS
SOUTHERN SASKATCHEWAN ON SUNDAY...AND THROUGH SOUTHERN MANITOBA
SUNDAY NIGHT INTO EARLY MONDAY. EXPECT PRECIP FOCUS TO START OUT
IN WEST-CENTRAL DURING THE DAY ON SUNDAY...THEN WORK TOWARDS THE
EAST SUNDAY NIGHT/EARLY MONDAY WITH PRECIP TAPERING FROM WEST TO
EAST THROUGH THE DAY ON MONDAY. EXPECT A QUIET PERIOD ON TUESDAY
AS FAST MOVING RIDGE PASSES OVER BEHIND DEPARTING SYSTEM BEFORE
SOUTHWESTERLY FLOW SETS UP OVER THE AREA. MODELS DIFFER SOME ON
HOW STRONG THIS FLOW IS...BUT THE MAIN POINT IS THAT THIS WILL
BRING THE NEXT ROUND OF PRECIPITATION CHANCES TO THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1241 PM CDT SAT AUG 16 2014
MVFR/IFR CONDITIONS IN SHOWERS AND THUNDERSTORMS IS
EXPECTED AT KBIS/KMOT/KJMS THIS AFTERNOON...POSSIBLY CONTINUING
INTO THE EVENING AT KJMS. ANOTHER ROUND OF POSSIBLY SEVERE STORMS
IS EXPECTED ACROSS THE AREA ON SUNDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...JPM
LONG TERM...JJS
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
355 PM EDT SAT AUG 16 2014
.SYNOPSIS...
A SLOW MOVING LOW PRESSURE SYSTEM OVER THE MID MISSISSIPPI VALLEY
SATURDAY EVENING WILL CONTINUE TO CREEP SLOWLY EASTWARD AS IT
SLOWLY WEAKENS. A PLUME OF UNSEASONABLY DEEP MOISTURE AHEAD OF THE
SYSTEM WILL CONTINUE TO SPREAD INTO AND THROUGH THE OHIO VALLEY
TONIGHT AND SUNDAY...AND THIS MOISTURE AND COMBINED WITH SUBTLE
DISTURBANCES AHEAD OF THE LOW WILL CONTINUE TO ALLOW SHOWERS TO
DEVELOP AT TIMES TONIGHT THROUGH SUNDAY IN SCATTERED FASHION. THE
SLOW MOVING LOW WILL MOVE INTO THE TRI STATE ON SUNDAY NIGHT AND
MONDAY...SHIFTING EAST OF THE AREA MONDAY NIGHT. THIS WILL BRING
SHOWERS AND A FEW THUNDERSTORMS...PRIMARILY TO AREAS ALONG AND
SOUTH OF THE OHIO RIVER...BUT ALL AREAS WILL SEE AT LEAST SOME
THREAT OF RAIN WITH THIS SYSTEM. IT WILL BE HUMID AND MILD DESPITE
AMPLE CLOUDS SUNDAY AND MONDAY. IN THE WAKE OF THIS SYSTEM ON
TUESDAY...AND CONTINUING THROUGH THE REST OF THE WORK WEEK...WILL
BE A WARM AND MUGGY AIRMASS WITH DAILY THREATS FOR SHOWERS AND
THUNDERSTORMS.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
GOES WATER VAPOR AND VISIBLE SATELLITE IMAGERY PLACE THE CENTER OF
THE WEAK CLOSED LOW OVER NORTHEAST MISSOURI THIS AFTERNOON. OUR
POOL OF UNSEASONABLY LOW DEWPTS /40S/ WHICH ALLOWED FOR SEVERAL
CHILLY NIGHTS WAS QUICKLY BEING REPLACED AN EQUALLY IMPRESSIVE
PLUME OF ABOVE NORMAL MOISTURE POISED JUST TO THE WEST...WHERE
RTMA DWPT ANALYSIS SHOWS WIDESPREAD MID 60S TO LOWER 70S DWPTS
NEAR AND AHEAD OF THE INBOUND CLOSED LOW.
THE 16.12Z RAOBS CLEARLY SHOWED THIS IMPRESSIVE MOISTURE
GRADIENT...WITH A 0.55" PWAT AT KILN TO A 1.82" PWAT AT KILX
/CENTRAL ILLINOIS/ WHICH IS ABOUT 1.5 STANDARD DEVIATIONS ABOVE
CLIMO...OR ABOUT 140% NORMAL.
LEADING EDGE MOISTURE TRANSPORT/THETA-E ADVECTION IS RESPONSIBLE
FOR A WEAKENING AREA OF SPRINKLES/VERY LIGHT SHOWERS ALONG AND
NORTH OF I-70 TODAY AND THIS WILL CONTINUE TO PETER OUT AS OUTRUNS
THE BETTER MOISTURE TO THE WEST. SO CARRYING SMALL CHANCES OF RAIN
LATE AFTERNOON/EARLY EVENING ALONG THIS AXIS AS MANY SITES HAVE
NOT BEEN MEASURING WITH THE SPRINKLES.
INTO THE EVENING AND OVERNIGHT AS THE LOW CREEPS SLOWLY
EASTWARD...SUBTLE MID LEVEL ENERGY SHEARING DOWNSTREAM FROM THE
WOBBLY CLOSED LOW WILL INDUCE MORE SCT SHRA AND A FEW STORMS.
LOCATION IS STILL VERY MUCH IN QUESTION GIVEN LACK OF APPRECIABLE
LOW LEVEL FORCING. RECENT HRRR RUNS /EXPERIMENTAL ESRL AND
PARALLEL NCEP/ HAVE BEEN ATTEMPTING TO FOCUS LIGHT/MOD RAIN
SHOWERS NEAR AND SOUTH OF THE OHIO RIVER CLOSER TO NOSE OF MODEST
LOW LEVEL JET POINTING INTO SRN IND. 16.12Z ECMWF ALSO FAVORING
THE SOUTH AS IS 16.12Z GFS WITH SCT SHRA. HOWEVER 16.12Z NCEP-
BASED ARW-WRF...NMM-WRF...AND SREF PROBABILITIES SEEM TO BE
LATCHING ONTO MORE OF A WEAK S/W DRIVEN RAIN CHANCE NORTH OF THE
OHIO RIVER. THERE/S SOME SUPPORT FOR BOTH...SO AM NOT GOING TO TRY
AND GET CUTE AND WILL INDICATE BROAD/MODERATE THREAT OF SHOWERS
TONIGHT OVER MOST AREAS. ACTIVITY EITHER WAY WON/T BE
WIDESPREAD...AND THUNDER THREATS SEEM RATHER LOW GIVEN STILL-
ARRIVING INSTBY ALOFT. GIVEN THE HUGE INCREASE IN MOISTURE THAT IS
OCCURRING...LOWS TONIGHT ABOUT 15 DEGREES HIGHER THAN LAST NIGHT.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
THE WEAK CLOSED LOW DRIFTING SOUTHEAST THROUGH THE MID MISSISSIPPI
VALLEY WILL BEGIN TO WEAKEN FURTHER AND SHEAR EASTWARD MORE
QUICKLY BEGINNING SUNDAY INTO SUNDAY NIGHT. THIS PROCESS STILL
KEEPS THE BULK OF THE FORCING WEST /ESPECIALLY SOUTHWEST/ OF THE
ILN FORECAST AREA ON SUNDAY...WHILE A COLD FRONT THAT HAS DROPPED
INTO NRN OHIO ATTENDANT TO ENERGY DIVING THROUGH SERN CANADA COMES
TO A HALT. BUT TROPOSPHERIC MOISTURE WILL CONTINUE TO BUILD WITH
PWATS EXCEEDING 1.75" ACROSS THE SOUTHERN FORECAST AREA. AREAS OF
SHOWERS WILL STILL BE POSSIBLE ACROSS THE AREA IN THE WEAKLY
FORCED REGION DOWNSTREAM OF THE WEAK CLOSED LOW...BUT DON/T SEE
MORE ORGANIZED ACTIVITY PUSHING INTO THE SOUTHERN/WESTERN AREAS
UNTIL EARLY SUNDAY EVENING OR INTO SUNDAY NIGHT. FLOW IS PRETTY
WEAK OVERALL SO NOT EXPECTING ANY THREAT OF SEVERE...BUT
INDIVIDUAL CORES WILL BE SLOW MOVING AND WITH THE AMPLE MOISTURE
THERE COULD BE SOME LOCALIZED HEAVY RAIN LATER SUNDAY NIGHT INTO
MONDAY IN OUR SOUTH. THINK OVERALL THIS THREAT IS LOWER THAN WHAT
PREVIOUS GUIDANCE HAD INDICATED...AS MODELS HAVE TRENDED
FASTER/WEAKER/MORE SHEARED WITH THE CLOSE LOW AS IT SHIFTS ACROSS
KENTUCKY AND OPENS UP AND BECOMES MORE PROGRESSIVE. NOTICED WPC
STILL KEEPS FAR SOUTHERN AREAS IN SLGT RISK FOR FLASH FLOOD
EXCEEDING RAINS...SO WILL KEEP THIS IN THE HAZ WX OUTLOOK BUT
REFINE THE THREAT AREA TO CLOSER TO THE TRACK OF MID LEVEL
CIRCULATION WHERE POTENTIAL FOR REGENERATION ALONG THE MAJOR AXIS
OF SHOWER/STORM POTENTIAL IS GREATEST. AMPLE CLOUDS AGAIN EXPECTED
SUNDAY INTO MONDAY SHOULD KEEP HIGHS IN CHECK FOR THE MOST
PART...70S TO LOWER 80S...IN WHAT WILL BE QUITE A HUMID AIRMASS.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
UPPER LEVEL RIDGING WILL BUILD FROM THE GULF COAST UP INTO THE
CENTRAL PLAINS THROUGH THE END OF THE WEEK. THIS WILL KEEP THE MID
OHIO VALLEY IN NORTHWEST FLOW ALOFT THROUGH MID TO LATE WEEK BEFORE
POSSIBLY TRANSITIONING TO MORE OF A NORTHERLY FLOW PATTERN ALOFT
HEADING INTO NEXT WEEKEND. A SERIES OF MID LEVEL SHORTWAVES ARE
FORECAST TO DROP DOWN THROUGH THE REGION THROUGH MUCH OF THE LONG
TERM PERIOD. THIS WILL RESULT IN A CONTINUED CHANCE OF
SHOWERS/THUNDERSTORMS THROUGH THE WEEK. HOWEVER...THE MODELS TEND TO
STRUGGLE WITH THE TIMING/PLACEMENT OF SHORT WAVES IN THIS KIND OF A
PATTERN. WILL THEREFORE GENERALLY JUST KEEP POPS IN THE CHANCE
CATEGORY WITH A BIT OF A DIURNAL ENHANCEMENT TO THEM. GIVEN THE
NORTHWEST FLOW PATTERN...EXPECT SOMEWHAT OF A NORTHEAST TO SOUTHWEST
TEMPERATURE GRADIENT ACROSS THE AREA THROUGH THE WEEK BUT OVERALL
TEMPERATURES SHOULD BE FAIRLY SEASONABLE.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
MAINLY VFR CONDITIONS ARE EXPECTED TO PERSIST. HOWEVER...MOISTURE
IS INCREASING IN A SOUTHWEST FLOW WELL AHEAD OF LOW PRESSURE
NEARING THE MISSISSIPPI RIVER. THE MOISTURE IS BEING
ISENTROPICALLY LIFTED IN THE VICINITY OF A WEAK WARM FRONTAL
BOUNDARY TO PRODUCE A FEW SHOWERS. IT APPEARS THAT DAY WILL BE
MOST AFFECTED BY THE SHOWERS THIS AFTERNOON. MODELS INDICATE
SCATTERED SHOWERS WILL PERSIST TONIGHT AS THE AIRMASS GROWS EVEN MORE
HUMID...AND BR MAY REDUCE VISIBILITIES TO MVFR AT LUK AND ILN.
FOR SUNDAY...MORE SHOWERS WILL BE POSSIBLE AT CVG AND LUK AS
FORCING WINDS UP AHEAD OF THE APPROACHING LOW. WINDS WILL BE OUT
OF THE SOUTHWEST AROUND 10 KNOTS TODAY...SHIFTING TO SOUTH ON SUNDAY.
OUTLOOK...THUNDERSTORMS POSSIBLE SUNDAY NIGHT THROUGH WEDNESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...BINAU
NEAR TERM...BINAU
SHORT TERM...BINAU
LONG TERM...JGL
AVIATION...CONIGLIO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
542 PM EDT SAT AUG 16 2014
.SYNOPSIS...
THE UNSEASONABLY DEEP TROUGH AND COOL DRY AIR WILL SHIFT TO OUR
EAST. A NORTHWEST FLOW PATTERN WILL DEVELOP. THE MODELS SHOW TWO
SHORTWAVES IN THE NW FLOW TO AFFECT THE REGION. FIRST ONE SUNDAY
AND THE SECOND ONE ABOUT TUESDAY. AT THIS TIME THE SECOND ONE
LOOKS WETTER. THE EVOLVING HIGH LATITUDE BLOCKING 500 HPA HIGH
COULD KEEP MAIN SHORTWAVE TRACK SUPPRESSED TO OUR SOUTH. THE
DEVELOPING 5900M RIDGE OVER THE SOUTHERN USA THIS WEEK SHOULD NOT
AFFECT US OTHER THAN KEEPING THE REGION IN NW FLOW.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
SHAPING FOR A NICE AFTERNOON AS FIRST WAVE OFF CIRRUS IS EXITING
EASTERN AREAS. NEXT WAVE TO OUR NW ALREADY SPREADING CIRRUS INTO
NW PA. TEMPERATURES CLOSE TO GUIDANCE.
THE HRRR SHOWS CHANCE OF SHOWERS ALONG NY BORDER BY 2200
UTC...LIGHT AND INCREASES THE INTENSITY AND POTENTIAL BETWEEN 0000
AND 0200 UTC THIS EVENING. MAINLY AFTER THIS FORECAST PERIOD.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM SUNDAY/...
THE 15Z HRRR IS WETTER IN APPEARANCE THAN THE NAM 12KM. BUT SHOWS
BEST CHANCE RAIN AND ISOLATED SHOWERS/THUNDERSTORMS THROUGH 0600
UTC. KEPT HIGHEST POPS NW PA IN THE 0000 TO 0600 UTC TIME PERIOD. THE
HRRR SYNTHETIC RADAR IMPLIES SOME SHOWERS TO CENTRAL PA AND THE
MASS WEAKENS. KEPT POPS LOWER TO SOUTH AND EAST.
THE SREF SHOWS THE RAINFALL PDF DROPPING AS THE WAVE MOVES INTO
CENTRAL AREAS IN THE 6 TO 18Z RANGE. TRIED TO SHOW IMPROVING
CONDITIONS AND POTENTIALLY A RELATIVELY NICE AFTERNOON OVER MOST
OF CENTRAL AND NORTHERN PA SUNDAY. THE 12Z GEFS IMPLIES PERHAPS
STRONGER FORCING IN THE AFTERNOON MAINLY SOUTH OF MASON/DIXON LINE
SO KEPT SOME CHANCE POPS NEAR AND ALONG IMMEDIATE BORDER WITH
MARYLAND IN THE AFTERNOON. SEE HOW THE 15Z SREF LOOKS LATER TODAY
WITH THIS.
THE 12Z GEFS/GFS/NAM AND THE 09Z SREF ALL CONTINUE TO SHOW TREND
FOR A PRETTY GOOD AFTERNOON IN CENTRAL AND NORTHERN PA. THE
CONVECTIVE ALLOWING 4KM NAM IMPLIES SHOWERS SCATTERED ABOUT IN
CENTRAL/SOUTHERN PA IN MORNING. THEN BEST IMPLIED AREA IS SOUTH OF
THE MARYLAND BORDER SUNDAY AFTERNOON. GRIDS SHOW CHANCE POPS ONLY
IN THE SOUTH.
TEMPERATURES LOOKS CLOSE TO SEASONAL AND NOT MUCH RAIN EXPECTED.
BEST SUNDAY MAY BE IN NW PA WITH THE OVERNIGHT RAINFALL. NOT MUCH
IN ANY MODEL AFTER 1200 UTC SUNDAY. TOTAL QPF IN MOST MODELS IS
ZERO. IN WEST MODELS IMPLY A FEW TENTHS IN MOUNTAINS OF
WESTERN/NORTHWESTERN PA. MOST BEFORE 1200 UTC.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
POST FRONTAL SUNDAY EVENING SHOULD SEE DRY NORTHWESTERLY AIR
ADVECT INTO THE REGION WITH LOWER PWATS INTO MONDAY AFTERNOON.
SREF/GEFS AND DETERMINISTIC MODELS SHOW A STRONG WARM SEASON WAVE
COMING IN FROM THE WEST RELATIVELY FAST. THIS UPPER LEVEL
PERTURBATION SHOULD KEEP MAINLY TO THE SOUTH LATE MONDAY INTO
TUESDAY MORNING. THIS WAVE SHOULD SPREAD MORE CLOUDS AND BRING
RAIN WEST TO EAST ACROSS MAINLY THE SOUTHERN HALF OF PA LATE MONDAY
INTO TUESDAY.
THE BIG EVENT THIS UPCOMING WEEK WILL BE DUE TO THE LARGE UPPER
LEVEL LOW THAT WILL BE MOVING INTO THE GREAT LAKES REGION LATE
TUESDAY. THIS DEEP CLIPPER-LIKE CYCLONE...WITH A EAST TO WEST
BOUNDARY SHOULD BRING HIGH PWATS AND MOIST SOUTH TO SOUTHEASTERLY
FLOW OUT AHEAD OF THE CYCLONE. THIS COULD BE A HEAVY RAIN EVENT
WITH A SYNOPTIC TYPE (S-N FLOW) EVOLVING TO A FRONTAL TYPE WITH
EASTERLY FLOW. EVEN CRUDE GEFS SHOWS ANOMALOUS PWATS TUESDAY
AFTERNOON INTO WEDNESDAY...THOUGH THE STRONGEST ANOMALIES ARE
SOUTH. THIS IMPLIES A 1 TO 2 INCH RAINFALL IS POSSIBLE. THIS
EVENT HAS POTENTIAL TO BE A SIGNIFICANT RAINFALL EVENT.
LARGER SCALE MODELS SHOW NO SIGNIFICANT CAPE. RAIN/SHOWERS AND
PERHAPS ELEVATED CONVECTION WITH THIS EVENT. DUE TO TIME RANGE AND
PREDICTABILITY HORIZON HAVE INCREASED BUT TEMPERED QPF THROUGH
THIS PERIOD.
THE LARGE UPPER LEVEL LOW LOOKS TO SKIRT ALONG TO THE NORTH OF THE
REGION INTO WEDNESDAY...CUTTING OFF THE MAJOR MOISTURE. BOTH THE
GFS/EC HAVE SIMILAR POSITION AND TIMING WITH THE LOW...WITH
SHOWERY PRECIP POSSIBLE WEDNESDAY AFTERNOON. THIS LOW COULD
RETROGRADE INTO FRIDAY WHICH WILL LEND PRECIPITATION TO BE A
POSSIBILITY THROUGH FRIDAY AFTERNOON. KEPT POPS IN CHANCE RANGE
MOST OF THE TIME. PRETTY UNSETTLED AND RELATIVELY WET PATTERN INTO
NEXT WEEKEND.
&&
.AVIATION /22Z SATURDAY THROUGH THURSDAY/...
WIDESPREAD VFR CONDS ACROSS CENTRAL PA AS OF EARLY EVENING.
A WEAKENING COLD FRONT WILL PUSH SE INTO THE AREA TONIGHT...ACCOMPANIED
BY SCT -SHRA. HOWEVER...THE MAIN AVIATION CONCERN WILL BE THE
POTENTIAL OF LOW CIGS AT KBFD LATE TONIGHT...CAUSED BY PLUME OF
PRE-FRONTAL LOW LVL MOISTURE ASCENDING THE HIGH TERRAIN OF NW PA.
THE THREAT OF LOW CIGS WILL PUSH SOUTHWARD ALONG THE SPINE OF THE
ALLEGHENIES TO KJST IN THE 10Z-14Z TIME FRAME. FURTHER
EAST...A DRYING/DOWNSLOPING FLOW WILL MAKE ANY SIG RESTRICTIONS
MUCH LESS LIKELY.
DYING COLD FRONT WILL SETTLE SOUTH OF THE AREA DURING SUNDAY. ANY
LOW CIGS ARND KJST SHOULD GIVE WAY TO WIDESPREAD VFR CONDS ACROSS
CENTRAL PA...AS DRIER NW FLOW OVERSPREADS THE REGION.
OUTLOOK...
MON...AM FOG POSSIBLE N MTNS...THEN ISOLATED SHOWERS.
TUE...RAIN/LOW CIGS POSSIBLE...MAINLY SOUTHERN PA.
WED...SCT PM TSRA IMPACTS POSSIBLE W MTNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM
LONG TERM...GRUMM/CERU
AVIATION...GRUMM/FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
401 PM EDT SAT AUG 16 2014
.SYNOPSIS...
THE UNSEASONABLY DEEP TROUGH AND COOL DRY AIR WILL SHIFT TO OUR
EAST. A NORTHWEST FLOW PATTERN WILL DEVELOP. THE MODELS SHOW TWO
SHORTWAVES IN THE NW FLOW TO AFFECT THE REGION. FIRST ONE SUNDAY
AND THE SECOND ONE ABOUT TUESDAY. AT THIS TIME THE SECOND ONE
LOOKS WETTER. THE EVOLVING HIGH LATITUDE BLOCKING 500 HPA HIGH
COULD KEEP MAIN SHORTWAVE TRACK SUPPRESSED TO OUR SOUTH. THE
DEVELOPING 5900M RIDGE OVER THE SOUTHERN USA THIS WEEK SHOULD NOT
AFFECT US OTHER THAN KEEPING THE REGION IN NW FLOW.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
SHAPING FOR A NICE AFTERNOON AS FIRST WAVE OFF CIRRUS IS EXITING
EASTERN AREAS. NEXT WAVE TO OUR NW ALREADY SPREADING CIRRUS INTO
NW PA. TEMPERATURES CLOSE TO GUIDANCE.
THE HRRR SHOWS CHANCE OF SHOWERS ALONG NY BORDER BY 2200
UTC...LIGHT AND INCREASES THE INTENSITY AND POTENTIAL BETWEEN 0000
AND 0200 UTC THIS EVENING. MAINLY AFTER THIS FORECAST PERIOD.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM SUNDAY/...
THE 15Z HRRR IS WETTER IN APPEARANCE THAN THE NAM 12KM. BUT SHOWS
BEST CHANCE RAIN AND ISOLATED SHOWERS/THUNDERSTORMS THROUGH 0600
UTC. KEPT HIGHEST POPS NW PA IN THE 0000 TO 0600 UTC TIME PERIOD. THE
HRRR SYNTHETIC RADAR IMPLIES SOME SHOWERS TO CENTRAL PA AND THE
MASS WEAKENS. KEPT POPS LOWER TO SOUTH AND EAST.
THE SREF SHOWS THE RAINFALL PDF DROPPING AS THE WAVE MOVES INTO
CENTRAL AREAS IN THE 6 TO 18Z RANGE. TRIED TO SHOW IMPROVING
CONDITIONS AND POTENTIALLY A RELATIVELY NICE AFTERNOON OVER MOST
OF CENTRAL AND NORTHERN PA SUNDAY. THE 12Z GEFS IMPLIES PERHAPS
STRONGER FORCING IN THE AFTERNOON MAINLY SOUTH OF MASON/DIXON LINE
SO KEPT SOME CHANCE POPS NEAR AND ALONG IMMEDIATE BORDER WITH
MARYLAND IN THE AFTERNOON. SEE HOW THE 15Z SREF LOOKS LATER TODAY
WITH THIS.
THE 12Z GEFS/GFS/NAM AND THE 09Z SREF ALL CONTINUE TO SHOW TREND
FOR A PRETTY GOOD AFTERNOON IN CENTRAL AND NORTHERN PA. THE
CONVECTIVE ALLOWING 4KM NAM IMPLIES SHOWERS SCATTERED ABOUT IN
CENTRAL/SOUTHERN PA IN MORNING. THEN BEST IMPLIED AREA IS SOUTH OF
THE MARYLAND BORDER SUNDAY AFTERNOON. GRIDS SHOW CHANCE POPS ONLY
IN THE SOUTH.
TEMPERATURES LOOKS CLOSE TO SEASONAL AND NOT MUCH RAIN EXPECTED.
BEST SUNDAY MAY BE IN NW PA WITH THE OVERNIGHT RAINFALL. NOT MUCH
IN ANY MODEL AFTER 1200 UTC SUNDAY. TOTAL QPF IN MOST MODELS IS
ZERO. IN WEST MODELS IMPLY A FEW TENTHS IN MOUNTAINS OF
WESTERN/NORTHWESTERN PA. MOST BEFORE 1200 UTC.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
POST FRONTAL SUNDAY EVENING SHOULD SEE DRY NORTHWESTERLY AIR
ADVECT INTO THE REGION WITH LOWER PWATS INTO MONDAY AFTERNOON.
SREF/GEFS AND DETERMINISTIC MODELS SHOW A STRONG WARM SEASON WAVE
COMING IN FROM THE WEST RELATIVELY FAST. THIS UPPER LEVEL
PERTURBATION SHOULD KEEP MAINLY TO THE SOUTH LATE MONDAY INTO
TUESDAY MORNING. THIS WAVE SHOULD SPREAD MORE CLOUDS AND BRING
RAIN WEST TO EAST ACROSS MAINLY THE SOUTHERN HALF OF PA LATE MONDAY
INTO TUESDAY.
THE BIG EVENT THIS UPCOMING WEEK WILL BE DUE TO THE LARGE UPPER
LEVEL LOW THAT WILL BE MOVING INTO THE GREAT LAKES REGION LATE
TUESDAY. THIS DEEP CLIPPER-LIKE CYCLONE...WITH A EAST TO WEST
BOUNDARY SHOULD BRING HIGH PWATS AND MOIST SOUTH TO SOUTHEASTERLY
FLOW OUT AHEAD OF THE CYCLONE. THIS COULD BE A HEAVY RAIN EVENT
WITH A SYNOPTIC TYPE (S-N FLOW) EVOLVING TO A FRONTAL TYPE WITH
EASTERLY FLOW. EVEN CRUDE GEFS SHOWS ANOMALOUS PWATS TUESDAY
AFTERNOON INTO WEDNESDAY...THOUGH THE STRONGEST ANOMALIES ARE
SOUTH. THIS IMPLIES A 1 TO 2 INCH RAINFALL IS POSSIBLE. THIS
EVENT HAS POTENTIAL TO BE A SIGNIFICANT RAINFALL EVENT.
LARGER SCALE MODELS SHOW NO SIGNIFICANT CAPE. RAIN/SHOWERS AND
PERHAPS ELEVATED CONVECTION WITH THIS EVENT. DUE TO TIME RANGE AND
PREDICTABILITY HORIZON HAVE INCREASED BUT TEMPERED QPF THROUGH
THIS PERIOD.
THE LARGE UPPER LEVEL LOW LOOKS TO SKIRT ALONG TO THE NORTH OF THE
REGION INTO WEDNESDAY...CUTTING OFF THE MAJOR MOISTURE. BOTH THE
GFS/EC HAVE SIMILAR POSITION AND TIMING WITH THE LOW...WITH
SHOWERY PRECIP POSSIBLE WEDNESDAY AFTERNOON. THIS LOW COULD
RETROGRADE INTO FRIDAY WHICH WILL LEND PRECIPITATION TO BE A
POSSIBILITY THROUGH FRIDAY AFTERNOON. KEPT POPS IN CHANCE RANGE
MOST OF THE TIME. PRETTY UNSETTLED AND RELATIVELY WET PATTERN INTO
NEXT WEEKEND.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
VFR THE REST OF THIS AFTERNOON AND EVENING. SOME AREAS OF GUSTY
WINDS. FIRST BATCH HIGH CIRRUS PASSING TO OUR EAST. MORE TO OUR
NORTHWEST WILL SPREAD SOUTHEAST THIS AFTERNOON AND INTO EARLY
TONIGHT.
RAIN SHOWERS SOME POTENTIAL FOR MVFR OVERNIGHT IN NW PA. SOME
AREAS OF PATCH FOG AND MVFR ISOLATED IFR OVERNIGHT.
MAINLY VFR AND MVFR SUNDAY WITH SOME LIGHT RAIN SHOWER POTENTIAL
WHICH MOVES TOWARD MARYLAND BORDER DURING THE DAY.
SOME PATCHY FOG OVERNIGHT SUNDAY INTO MONDAY WITH MVFR/IFR AROUND
SUNRISE.
CHANCE MVFR/IFR WITH WEATHER SYSTEM MONDAY NIGHT INTO TUESDAY.
OUTLOOK... SUN...AM LOW CIGS/SHRA POSSIBLE AT KBFD.
MON...AM FOG POSSIBLE N MTNS...THEN ISOLATED SHOWERS.
TUE...RAIN/LOW CIGS POSSIBLE...MAINLY SOUTHERN PA.
WED...SCT PM TSRA IMPACTS POSSIBLE W MTNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM
LONG TERM...GRUMM/CERU
AVIATION...GRUMM
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
205 PM EDT SAT AUG 16 2014
.SYNOPSIS...
THE UNSEASONABLY DEEP TROUGH AND COOL DRY AIR WILL SHIFT TO OUR
EAST. A NORTHWEST FLOW PATTERN WILL DEVELOP. THE MODELS SHOW TWO
SHORTWAVES IN THE NW FLOW TO AFFECT THE REGION. FIRST ONE SUNDAY
AND THE SECOND ONE ABOUT TUESDAY. AT THIS TIME THE SECOND ONE
LOOKS WETTER. THE EVOLVING HIGH LATITUDE BLOCKING 500 HPA HIGH
COULD KEEP MAIN SHORTWAVE TRACK SUPPRESSED TO OUR SOUTH. THE
DEVELOPING 5900M RIDGE OVER THE SOUTHERN USA THIS WEEK SHOULD NOT
AFFECT US OTHER THAN KEEPING THE REGION IN NW FLOW.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
SHAPING FOR A NICE AFTERNOON AS FIRST WAVE OFF CIRRUS IS EXITING
EASTERN AREAS. NEXT WAVE TO OUR NW ALREADY SPREADING CIRRUS INTO
NW PA. TEMPERATURES CLOSE TO GUIDANCE.
THE HRRR SHOWS CHANCE OF SHOWERS ALONG NY BORDER BY 2200
UTC...LIGHT AND INCREASES THE INTENSITY AND POTENTIAL BETWEEN 0000
AND 0200 UTC THIS EVENING. MAINLY AFTER THIS FORECAST PERIOD.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM SUNDAY/...
THE 15Z HRRR IS WETTER IN APPEARANCE THAN THE NAM 12KM. BUT SHOWS
BEST CHANCE RAIN AND ISOLATED SHOWERS/THUNDERSTORMS THROUGH 0600
UTC. KEPT HIGHEST POPS NW PA IN THE 0000 TO 0600 UTC TIME PERIOD. THE
HRRR SYNTHETIC RADAR IMPLIES SOME SHOWERS TO CENTRAL PA AND THE
MASS WEAKENS. KEPT POPS LOWER TO SOUTH AND EAST.
THE SREF SHOWS THE RAINFALL PDF DROPPING AS THE WAVE MOVES INTO
CENTRAL AREAS IN THE 6 TO 18Z RANGE. TRIED TO SHOW IMPROVING
CONDITIONS AND POTENTIALLY A RELATIVELY NICE AFTERNOON OVER MOST
OF CENTRAL AND NORTHERN PA SUNDAY. THE 12Z GEFS IMPLIES PERHAPS
STRONGER FORCING IN THE AFTERNOON MAINLY SOUTH OF MASON/DIXON LINE
SO KEPT SOME CHANCE POPS NEAR AND ALONG IMMEDIATE BORDER WITH
MARYLAND IN THE AFTERNOON. SEE HOW THE 15Z SREF LOOKS LATER TODAY
WITH THIS.
THE 12Z GEFS/GFS/NAM AND THE 09Z SREF ALL CONTINUE TO SHOW TREND
FOR A PRETTY GOOD AFTERNOON IN CENTRAL AND NORTHERN PA. THE
CONVECTIVE ALLOWING 4KM NAM IMPLIES SHOWERS SCATTERED ABOUT IN
CENTRAL/SOUTHERN PA IN MORNING. THEN BEST IMPLIED AREA IS SOUTH OF
THE MARYLAND BORDER SUNDAY AFTERNOON. GRIDS SHOW CHANCE POPS ONLY
IN THE SOUTH.
TEMPERATURES LOOKS CLOSE TO SEASONAL AND NOT MUCH RAIN EXPECTED.
BEST SUNDAY MAY BE IN NW PA WITH THE OVERNIGHT RAINFALL. NOT MUCH
IN ANY MODEL AFTER 1200 UTC SUNDAY. TOTAL QPF IN MOST MODELS IS
ZERO. IN WEST MODELS IMPLY A FEW TENTHS IN MOUNTAINS OF
WESTERN/NORTHWESTERN PA. MOST BEFORE 1200 UTC.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
BIG EVENT OF WEEK COULD BE RAINFALL TUESDAY....
HIGHEST PROBABILITY OF RAIN THROUGH 8 AM SUNDAY WOULD BE NORTHERN
PA. LOW PROBABILITY OF OVER 1.00 INCH OF RAINFALL IN NORTHERN
AREAS. ENSEMBLES SUGGEST 30 PERCENT OF MEMBERS HAVE MUCH MORE THAN
0.75 INCHES OF QPF.
SUNDAY MODELS FOCUS HIGHER PROBABILITIES IN CENTRAL AND SOUTHERN
PA. MOST AREAS OVER THE PERIOD SUNDAY WILL LIKELY SEE 0.10 TO 0.50
INCHES OF RAIN AS FRONT SAGS SOUTHWARD.
DRY AIR MOVING BEHIND FRONT COULD PROVIDE SOME SUN IN CENTRAL
NORTHERN AREAS IN AFTERNOON SUNDAY.
MONDAY SHOULD START OFF RELATIVELY DRIER...SREF/GEFS AND
DETERMINISTIC MODELS SHOW A STRONG WARM SEASON WAVE COMING IN
FROM THE WEST RELATIVELY FAST. THIS WAVE SHOULD SPREAD MORE CLOUDS
AND BRING RAIN WEST TO EAST ACROSS PA MONDAY INTO OVERNIGHT
TUESDAY.
EARLY WEEK RAIN SHOULD BE MAIN EVENT...
THE RAIN EVENT OVERNIGHT MONDAY INTO TUESDAY AS FORECAST IS THE
MAIN EVENT OF THE COMING WEEK. DEEP CLIPPER-LIKE CYCLONE...EAST-
WEST BOUNDARY...HIGH PW AND EASTERLY FLOW NORTH OF THE CYCLONE.
THIS COULD BE A HEAVY RAIN EVENT WITH A SYNOPTIC TYPE (S-N FLOW)
EVOLVING TO A FRONTAL TYPE WITH EASTERLY FLOW. EVEN CRUDE GEFS
SHOWS EASTERLY WIND ANOMALIES. GEFS IMPLIES GOOD 1 TO 2 INCH
RAINFALL IS POSSIBLE. THIS EVENT HAS POTENTIAL TO BE A SIGNIFICANT
RAINFALL EVENT.
LARGER SCALE MODELS SHOW NO SIGNIFICANT CAPE. RAIN/SHOWERS AND
PERHAPS ELEVATED CONVECTION WITH THIS EVENT. DUE TO TIME RANGE AND
PREDICTABILITY HORIZON DID NOT GO BIG IN QPF GRIDS AT THIS TIME.
SUSPECT IF THIS SYSTEM DEVELOPS AS FORECAST...OUR HIGHS TUESDAY
COULD GET CRUSHED. BUT AT THIS TIME THIS IS THE EVENT TO MONITOR.
AS THIS SYSTEM SLOWLY GOES BY RAINFALL SHOULD DIMINISH TUESDAY
AND WEDNESDAY. WEDNESDAY AS FORECAST LOOKS RELATIVELY DRY. THEN PW
VALUES RISE AGAIN.
LATER PART OF WEEK LOOKS POTENTIALLY SHOWERY. THE LARGE 500 HPA
RIDGE RETROGRADING TO A POSITION NORTH OF THE GREAT LAKES WILL
LIKELY ALLOW MOISTURE INTO OUR REGION AND KEEP A LARGER SCALE
FRONTAL BOUNDARY NEARBY. THE CMCEFS AND GEFS WILL LIKELY NOT
CAPTURE ANY SHORT WAVES CUTTING UNDER THIS BLOCK. KEPT POPS IN
CHANCE RANGE MOST OF THE TIME. PRETTY UNSETTLED AND RELATIVELY WET
PATTERN LAST PART OF THE COMING WORK WEEK.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
VFR THE REST OF THIS AFTERNOON AND EVENING. SOME AREAS OF GUSTY
WINDS. FIRST BATCH HIGH CIRRUS PASSING TO OUR EAST. MORE TO OUR
NORTHWEST WILL SPREAD SOUTHEAST THIS AFTERNOON AND INTO EARLY
TONIGHT.
RAIN SHOWERS SOME POTENTIAL FOR MVFR OVERNIGHT IN NW PA. SOME
AREAS OF PATCH FOG AND MVFR ISOLATED IFR OVERNIGHT.
MAINLY VFR AND MVFR SUNDAY WITH SOME LIGHT RAIN SHOWER POTENTIAL
WHICH MOVES TOWARD MARYLAND BORDER DURING THE DAY.
SOME PATCHY FOG OVERNIGHT SUNDAY INTO MONDAY WITH MVFR/IFR AROUND
SUNRISE.
CHANCE MVFR/IFR WITH WEATHER SYSTEM MONDAY NIGHT INTO TUESDAY.
OUTLOOK... SUN...AM LOW CIGS/SHRA POSSIBLE AT KBFD.
MON...AM FOG POSSIBLE N MTNS...THEN ISOLATED SHOWERS.
TUE...RAIN/LOW CIGS POSSIBLE...MAINLY SOUTHERN PA.
WED...SCT PM TSRA IMPACTS POSSIBLE W MTNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM
LONG TERM...GRUMM
AVIATION...GRUMM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1130 AM CDT SAT AUG 16 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 253 AM CDT SAT AUG 16 2014
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING OVER THE SOUTHWESTERN U.S....AN UPPER LOW IN NORTHERN
IDAHO...SHORTWAVES OVER THE DAKOTAS AND THE KANSAS CITY AREA...AND A
DEEP UPPER TROUGH OVER EASTERN CANADA INTO THE NORTHEAST U.S..
WITHIN THIS TROUGH...A FAIRLY POTENT SHORTWAVE WAS APPROACHING LAKE
SUPERIOR. THE FORECAST AREA LIES IN THE NORTHWEST FLOW ON THE
WESTERN EDGE OF THE TROUGH...BUT STILL NEAR THE INFLECTION POINT
FAVORING SUBSIDENCE AND HIGH PRESSURE AT THE SURFACE. THUS...ONLY
SOME SCATTERED CIRRUS CLOUDS HAVE BEEN TRACKING ACROSS THE FORECAST
AREA. 15.00Z MODELS DEFINITELY OVER-FORECAST THE PRECIPITABLE
WATER...INSTEAD OF BEING 1.5-1.75 INCHES IS ONLY 1-1.25 INCHES PER
GOES DERIVED IMAGERY. SURFACE DEWPOINTS ARE HIGHER...THOUGH...WHICH
WITH RADIATIONAL COOLING HAS LED TO SOME BR AND LOW STRATUS
DEVELOPMENT. THE NEAREST AREAS WHERE PRECIPITATION IS OCCURRING ARE
SOUTH OF I-80 IN IOWA ASSOCIATED WITH THE KANSAS CITY SHORTWAVE...
OVER THE CENTRAL DAKOTAS WITH THE SHORTWAVE THERE...AND THE MN
ARROWHEAD INTO UPPER MICHIGAN AHEAD OF THE APPROACHING SHORTWAVE.
THIS LAST PRECIPITATION AREA IS ALSO SUPPORTED BY A SURFACE COLD
FRONT TRACKING WITH IT.
500MB HEIGHTS ARE PROGGED TO RISE OVER THE NEXT 24 HOURS IN RESPONSE
TO THE UPPER LOW OVER NORTHERN ONTARIO PUSHING EAST INTO SOUTH
CENTRAL SASKATCHEWAN. TYPICALLY WHEN SEEING HEIGHT RISES ONE WOULD
EXPECT A WARM ADVECTION PATTERN. HOWEVER...IN THIS CASE...THE
SHORTWAVE APPROACHING LAKE SUPERIOR WILL DROP INTO THE EASTERN GREAT
LAKES THIS EVENING...SENDING ITS ASSOCIATED COLD FRONT THROUGH THE
FORECAST AREA.
MUCH OF THIS MORNING CONTINUES TO LOOK DRY AS ANY SHOWER ACTIVITY
ASSOCIATED WITH THE KANSAS CITY SHORTWAVE STAYS JUST TO THE
SOUTH...AS DEPICTED IN THE LATEST RAP/HRRR DATA. ANY FOG/STRATUS
SHOULD DISSIPATE WITHIN A FEW HOURS AFTER SUNRISE. HEADING INTO THE
AFTERNOON...DETERMINISTIC AND HIGH RESOLUTION MODELS REMAIN IN GOOD
AGREEMENT THAT THIS COLD FRONT WILL HELP INITIATE CONVECTION NORTH
OF I-94. THIS IS A RESULT TOO OF TEMPERATURES CLIMBING INTO THE 80S
FROM 850MB TEMPS AROUND 16C...AS WELL AS DEWPOINTS CLIMBING INTO THE
MID TO UPPER 60S...COMBINING TO PRODUCE MLCAPES OF 1000-2000 J/KG.
THIS CAPE IS OVERALL SKINNY AND 0-6 KM/0-3KM SHEAR ARE 20 KT OR LESS
WHICH WILL LIMIT SEVERE WEATHER POTENTIAL. HOWEVER...EQUILIBRIUM
LEVELS ARE NEAR 40000 FT AND WARM CLOUD DEPTHS APPROACH 4000
METERS...SO THE STORMS ARE LIKELY TO PRODUCE HEAVY RAIN. THE AMOUNT
OF CONVECTION SEEMS SCATTERED AT BEST SINCE THE BETTER FRONTAL
CONVERGENCE AND DYNAMIC FORCING ARE FARTHER EAST...MORE TOWARDS
LOWER MICHIGAN CLOSER TO THE SHORTWAVE TRACK.
CONVECTION NORTH OF I-94 IN THE AFTERNOON THEN LOOKS TO DROP SOUTH
IN THE EVENING WITH THE COLD FRONT. HOWEVER...COOLING TEMPERATURES
FROM LOSS OF DAYTIME HEATING AND THE FACT LITTLE CONVERGENCE EXISTS
ON THE FRONT WILL LIKELY RESULT IN A DIMINISHING TREND TO THE
CONVECTION. THERE MAY NOT BE MUCH LEFT AFTER 06Z AS THE 16.00Z GFS
SUGGESTS. IN THE WAKE OF THE COLD FRONT...IT APPEARS A LOW STRATUS
DECK MAY END UP DEVELOPING AND ADVECTING SOUTHWESTWARD. BASED ON
FORECAST SOUNDINGS...LOCATIONS SOUTHWEST OF I-94 APPEAR TO HAVE THE
GREATEST CHANCE OF SEEING THIS STRATUS DECK. COOLING 925MB TEMPS ON
THE EASTERLY FLOW SHOULD RESULT IN A COOLER NIGHT...ESPECIALLY IN
CENTRAL WI.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 253 AM CDT SAT AUG 16 2014
MAIN ISSUE ON SUNDAY RELATES TO THE SHORTWAVE OVER THE DAKOTAS
CURRENTLY. THE 16.00Z GFS/NAM TRACK THIS SHORTWAVE ACROSS MN DURING
THE DAY...WHICH HELPS PRODUCE SOME SHOWERS AND EMBEDDED STORMS
MOSTLY JUST WEST OF THE FORECAST AREA. PART OF THE REASON THIS
PRECIPITATION DOESNT DEVELOP FARTHER EAST IS A DRY EASTERLY FLOW
PROVIDED BY HIGH PRESSURE BUILDING OVER UPPER MI IN THE WAKE OF
TONIGHTS COLD FRONT. ITS POSSIBLE SOME OF THE SHOWER ACTIVITY
CREEPS INTO SOUTHEAST MN...BUT CONFIDENCE IS NOT HIGH ENOUGH TO PUT
ANY CHANCES IN YET. OTHERWISE...SUNDAY LOOKS COOLER THAN TODAY DUE
TO THE EASTERLY FLOW...MORNING STRATUS AND 925MB TEMPS ABOUT 4C
COOLER.
SUNDAY NIGHT NOW POSES SOME FORECAST CHALLENGE. 16.00Z ECMWF IS
SLOWER THAN THE GFS/NAM TRACKING THE SHORTWAVE EASTWARD OUT OF
MN...AND IN FACT HAS THE WAVE MOVE RIGHT ACROSS THE FORECAST AREA.
ADDITIONALLY...IN THE ECMWF...A SURGE OF 850MB MOISTURE TRANSPORT
ACCOMPANIES THE WAVE...HELPING TO PRODUCE SHOWERS AND STORMS ACROSS
MUCH OF THE AREA AND ESPECIALLY AFTER 06Z. NOW...THE 16.00Z GFS ALSO
DEPICTS AN INCREASE OF 850MB MOISTURE TRANSPORT AND PRECIPITATION...
BUT ITS MORE OVER NORTHWEST SECTIONS OF THE ARE AND IN RESPONSE TO
UPPER TROUGHING COMING INTO THE DAKOTAS. IN ANY EVENT...GIVEN THAT
THESE 2 MODELS ARE PRODUCING PRECIPITATION...FELT A NEED TO INCLUDE
20 PERCENT CHANCES IN FOR AT LEAST THE WEST HALF OF THE FORECAST
AREA. THESE MAY NEED TO BE INCREASED IF MODEL TRENDS CONTINUE.
MONDAY THROUGH TUESDAY...AND IN PARTICULARLY MONDAY NIGHT...STILL
REMAIN THE BEST CHANCE FOR WIDESPREAD RAIN. ALL MODELS ARE IN
AGREEMENT THAT THE CURRENT UPPER LOW OVER NORTHERN IDAHO...AND
ASSOCIATED GENERAL UPPER TROUGHING...WILL MOVE THROUGH THE FORECAST
AREA DURING THIS TIMEFRAME. A SURGE OF 1.5 INCH PRECIPITABLE WATER
COMBINED WITH DPVA FORCING FROM THE TROUGH...AS WELL AS INSTABILITY
SHOULD RESULT IN SHOWERS AND STORMS. MONDAY NIGHT SEEMS TO BE THE
BEST JUXTAPOSITION OF THE AFOREMENTIONED PARAMETERS AND THUS HIGHEST
CHANCES AROUND 70 PERCENT ARE CENTERED THERE. 0-6KM/0-3KM SHEAR
PROGGED LESS THAN 20 KT SO BRIEF HEAVY RAIN WOULD LIKELY BE THE MAIN
CONCERN WITH THE STORMS.
THE REST OF NEXT WEEK FEATURES THE UPPER LOW AND TROUGHING LIFTING
OUT OF THE REGION ON WEDNESDAY...FOLLOWED BY RIDGING BUILDING UP
ACROSS THE PLAINS AS TROUGHING REFORMS OVER THE PACIFIC NORTHWEST.
THIS SETUP IS FAVORABLE FOR BOTH WARM AND MOIST AIR ADVECTION...AND
AS SUCH MODELS CONTINUE TO OSCILLATE ON WHERE AND WHEN STORMS COULD
FIRE ON THE NOSE OF THIS ADVECTION. THEREFORE...FORECAST DEPICTS A
CONSENSUS WITH 20-40 PERCENT CHANCES FROM WEDNESDAY THROUGH FRIDAY.
THERE ARE SOME INDICATIONS WEDNESDAY COULD PAN OUT DRY...THUS LOWEST
CHANCES ARE CENTERED THEN. SEVERE WEATHER POTENTIAL WISE...IF THE
ECMWF PANS OUT...THERE COULD BE A SHOT FOR SOME ON THURSDAY. PLENTY
OF UNCERTAINTY OUT THERE...THOUGH. TEMPERATURES LOOK TO GRADUALLY
INCREASE EACH DAY WITH MOST DAYS AT OR ABOVE NORMAL. IT SHOULD BE
NOTED THAT IF ANY DAY ENDS UP WITH LESS CLOUDS...TEMPERATURES COULD
END UP WARMER THAN FORECAST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1130 AM CDT SAT AUG 16 2014
LOW STRATUS AND FOG SHOULD CONTINUE TO LIFT/BREAK UP EARLY THIS
AFTERNOON AS DAYTIME MIXING INCREASES. EXPECTING MORE STRATUS/FOG
DEVELOPMENT LATER TONIGHT...WITH SREF PROBABILITIES FAVORING THE
LOWER CIGS/VSBYS AT KRST. SUB 1 KFT CIGS LOOKS LIKELY AT BOTH
SITES...AND VSBYS COULD DROP BELOW 1SM AT KRST. WILL HOLD IN THE 1-
2SM RANGE FOR NOW. LOW STRATUS WILL HANG AROUND MOST OF THE MORNING
BEFORE MIXING CAN WORK ON LIFTING/BREAKING IT UP.
MEANWHILE...A COLD FRONT IS SLATED TO DROP SLOWLY SOUTH ACROSS WI/MN
TODAY/TONIGHT. NARROW REGION OF FRONTOGENETIC LIFT AROUND THE
BOUNDARY...AND IT WILL HAVE SOME DAYTIME INSTABILTY TO WORK ON.
EXPECTING SCATTERED SHRA/TS TO DEVELOP AROUND IT...MOSTLY WHEN
INSTABLITY IS AT ITS PEAK AND OVER WI. TO THE WEST...A WEAK
DISTURBANCE A LOFT WILL SPIN ACROSS THE PLAINS AND INTO MN TONIGHT.
THIS COULD WORK WITH THE FAR WESTERN REACHES OF THE FRONT TO SPARK A
FEW SHRA/TS. AT THIS TIME...THINK THE BETTER CHANCES WILL LIKE WEST
AND EAST OF KRST/KLSE...AND WILL LEAVE PCPN OUT OF THE FORECAST FOR
NOW. THAT SAID...IF IT BECOMES MORE LIKELY...IT WILL HAVE AN IMPACT
ON THE STRATUS/FOG POTENTIAL.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM....AJ
AVIATION.....RIECK