Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 07/20/13
AREA FORECAST DISCUSSION
NWS TUCSON AZ
910 AM MST THU JUL 18 2013
.SYNOPSIS...EXPECT SCATTERED THUNDERSTORMS MAINLY SOUTH AND
NORTHEAST OF TUCSON THROUGH TONIGHT. A LOW PRESSURE SYSTEM MOVING
SOUTH OF THE AREA WILL THEN ENHANCE THUNDERSTORM CHANCES STARTING
FRIDAY AND CONTINUING INTO THIS WEEKEND. THEREAFTER...THE NORMAL
CYCLE OF SCATTERED AFTERNOON AND EVENING THUNDERSTORMS WILL RETURN
BY THE MIDDLE OF NEXT WEEK. DAYTIME TEMPERATURES WILL BE SEVERAL
DEGREES BELOW NORMAL AS WELL.
&&
.DISCUSSION...VISIBLE SATELLITE IMAGERY AND SURFACE OBSERVATIONS
INDICATE A FEW TO SCATTERED MAINLY MID-LEVEL CLOUDS ACROSS SE AZ AT
THIS TIME. DEWPOINTS VALID 16Z RANGED MOSTLY FROM THE MID 50S-LOWER
60S F. THESE TEMPS WERE ABOUT 5 DEGS F LOWER FROM TUCSON WESTWARD
VERSUS 24 HOURS AGO...BUT DEWPOINTS WERE ABOUT 5 DEGS F HIGHER EAST
OF TUCSON. SURFACE TEMPS VALID 16Z WERE NEARLY IDENTICAL TO THIS
TIME WED.
18/12Z KTWC SOUNDING DEPICTED A DRIER REGIME VERSUS 24 HOURS...WITH
TOTAL PRECIP WATER OF 1.35 INCHES. A MARGINALLY UNSTABLE REGIME ALSO
EXISTED WITH LIFTED INDEX OF MINUS 2 AND MINIMAL CAPE. A FAIRLY
PRONOUNCED CAPPING INVERSION WAS NOTED AROUND 500 MB. BLENDED TOTAL
PRECIP WATER IMAGERY PRODUCT YIELDED VALUES RANGING FROM NEAR 1.25
INCHES EAST TO 1.40 INCHES ACROSS THE WESTERN DESERTS. 18/12Z UPPER
AIR PLOTS INDICATED 588 DM LOW PRESSURE CENTERED NEAR THE FAR SE AZ/
FAR SW NEW MEXICO BORDER...AND STRONG RIDGE THAT EXTENDED FROM THE
GREAT BASIN EWD INTO THE MID ATLANTIC/TIDEWATER REGIONS. LIGHT TO
MODERATE NLY/NELY FLOW ALOFT PREVAILED ACROSS MUCH OF SE AZ.
UPPER LOW IS PROGGED TO MOVE SLOWLY SW INTO NRN SONORA BY FRI
MORNING. 18/13Z RUC HRRR DEPICTS THE FAVORED AREAS FOR SCATTERED
SHOWERS/TSTMS TO OCCUR INTO EARLY THIS EVENING TO BE SOUTH OF TUCSON
ACROSS SRN COCHISE/SANTA CRUZ COUNTIES...AND NE OF TUCSON ACROSS NRN
GREENLEE AND GRAHAM COUNTIES. GIVEN THE AFOREMENTIONED CAPPING
INVERSION...BELIEVE CONVECTIVE ACTIVITY ESPECIALLY FOR THE TUCSON
METRO AREA WILL BE LIMITED UNTIL EARLY THIS EVENING. GIVEN THE
GENERALLY DRIER REGIME VERSUS 24 HOURS AGO...THE THREAT FOR HEAVY
RAINFALL SHOULD BE MITIGATED. BRIEF WIND GUSTS TO AROUND 40 MPH MAY
OCCUR WITH THE STRONGER THUNDERSTORMS...SIMILAR TO SPEEDS RECORDED AT
KSAD WED AFTERNOON.
THERE ARE NO UPDATES PLANNED FOR THE OFFICIAL FORECAST AT THIS TIME.
PLEASE REFER TO THE PREVIOUS DISCUSSION SECTION BELOW FOR ADDITIONAL
DETAIL.
&&
.PREV DISCUSSION /207 AM MST THU JUL 18 2013/...MODELS INDICATE THAT
THE LOW WILL CONSOLIDATE OVER THE GENERAL VICINITY OF THE CENTRAL
GULF OF CALIFORNIA BY LATE FRIDAY AFTERNOON. AS THIS OCCURS THE
UPPER HIGH...WHICH IS CURRENTLY OVER UTAH AND COLORADO WILL DRIFT
WEST OVER NEVADA WITH A RIDGE AXIS EXTENDING EAST INTO THE CENTRAL
PLAINS. THIS SETUP WILL RESULT IN AN EASTERLY COMPONENT TO THE WINDS
THROUGH AT LEAST THE WEEKEND. WINDS WILL TAKE ON A MORE SOUTH TO
SOUTHEASTERLY COMPONENT DURING THE EARLY TO MIDDLE OF NEXT WEEK AS
THE UPPER HIGH OVER NEVADA BEGINS MOVING EAST AND SETTLES OVER THE
CENTRAL TO SOUTHERN PLAINS BY THE MIDDLE OF NEXT WEEK.
MODELS ADVERTISE A VERY LARGE SWATH OF HIGH PW AIR MAKING ITS WAY UP
THE GULF OF CALIFORNIA AND INTO SOUTHWEST ARIZONA AS THE UPPER LOW
MOVES ACROSS NORTHERN MEXICO. PW`S ARE ADVERTISED TO BE ABOVE THE 2
INCH MARK OVER THE GULF OF CALIFORNIA AND WILL MAKE IT INTO
SOUTHWEST ARIZONA BY LATE FRIDAY OR EARLY SATURDAY. IN ADDITION...
MODELS SHOW THE BEST FORCING AND MOISTURE TRANSPORT TO BE ALONG THE
INTERNATIONAL BORDER BEGINNING FRIDAY AND CONTINUING THROUGH THE
WEEKEND. THAT SAID...I TWEAKED POPS UP A TAD ALONG THE BORDER AND
OUT WEST OVER THE TOHONO O`ODHAM NATION...SINCE STEERING WINDS WILL
PUSH ANY CONVECTION THAT DEVELOPS IN THAT DIRECTION. SO INSTEAD OF
THE TYPICAL 10-20% POP FOR THE CENTRAL AND WESTERN PORTIONS OF PIMA
COUNTY...WE WILL SEE MORE OF A SOLID CHANCE CATEGORY POP FOR THIS
AREA WITH LIKELY POPS IN A FEW PLACES RIGHT ALONG THE INTERNATIONAL
BORDER...ESPECIALLY ON SATURDAY.
DURING THE EARLY TO MIDDLE OF NEXT WEEK AS THE HIGH SHIFTS EAST OVER
THE PLAINS...THE MOISTURE WILL DECREASE AND WE WILL SEE MOSTLY
ISOLATED SHOWER/THUNDERSTORM ACTIVITY WITH SCATTERED POPS FOR THE
MOUNTAINS.
HIGHS GENERALLY 3 TO 7 DEGS BELOW NORMAL THROUGH TUESDAY...WITH THE
COOLEST DAYS BEING THIS WEEKEND WHEN HIGHS WILL BE ABOUT 5 TO 7 DEGS
BELOW NORMAL. ONLY SLIGHTLY BELOW NORMAL HIGHS FOR NEXT WEDNESDAY.
LOWS NEAR OR SLIGHTLY ABOVE NORMAL THROUGH NEXT TUESDAY...THEN ABOUT
3 TO 5 DEGS ABOVE NORMAL FOR WEDNESDAY MORNING.
&&
.AVIATION...EXPECT SCATTERED TSRA/SHRA ACROSS SE AZ THRU THIS
EVENING. THE FAVORED AREAS FOR PRECIP WILL BE SOUTH OF KTUS...
ESPECIALLY NEAR KDUG AND KOLS AND ACROSS NORTHERN GREENLEE AND
GRAHAM COUNTIES NE OF KTUS. MVFR CONDITIONS AND WIND GUSTS TO ABOUT
40 KTS WILL OCCUR WITH THE STRONGER THUNDERSTORMS. A FEW LINGERING
-SHRA LATE TONIGHT INTO FRIDAY MORNING. OTHERWISE...CLOUD DECKS THIS
MORNING GENERALLY ABOVE 12K FT AGL BECOMING 8-12K FT AGL THIS
AFTERNOON AND CONTINUING INTO FRIDAY MORNING. SURFACE WIND INTO
FRIDAY MORNING OR THRU 19/18Z ELY/SELY 5-15 KTS. SOMEWHAT STRONGER
WINDS ESPECIALLY VICINITY KTUS THRU FRIDAY MORNING. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...AMPLE MOISTURE IN COMBINATION WITH AN EASTERLY FLOW
REGIME WILL PROVIDE SCATTERED SHOWERS AND THUNDERSTORMS INTO THE
MIDDLE OF NEXT WEEK. THE STRONGER THUNDERSTORMS WILL BE CAPABLE OF
PRODUCING HEAVY DOWNPOURS AS WELL AS GUSTY AND ERRATIC WINDS.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
DISCUSSION/AVIATION...FRANCIS
PREVIOUS DISCUSSION...MOLLERE
FIRE WEATHER...MEADOWS/HUMPHREYS
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
848 PM MDT FRI JUL 19 2013
.UPDATE...
ISSUED AT 848 PM MDT FRI JUL 19 2013
DRIER AIR CONTINUES TO OVERTAKE THE FORECAST AREA THIS EVENING
WITH PRONOUNCED DECREASE IN CONVECTIVE ACTIVITY. COVERAGE HAS
DIMINISHED RATHER RAPIDLY WITH LOSS OF HEATING AND HAVE MADE
ADJUSTMENTS TO THE EVENING POP FIELDS BACK TO MORE ISOLATED AND
SCATTERED COVERAGE. EVENING SOUNDING REALLY TELLS THE TALE AS
PRECIPITABLE WATER VALUES HAVE DROPPED OFF BY NEARLY A HALF INCH
TO AROUND 0.80 INCHES. WITH COVERAGE AND AVAILABLE MOISTURE BOTH
DROPPING...HAVE WENT AHEAD AND DROPPED THE FLASH FLOOD WATCH.
WILL BE TAKING ANOTHER LOOK AT TEMPERATURES AS DEW POINTS CONTINUE
TO TUMBLE WITH SEVERAL SITES RUNNING A GOOD 10 TO 20 DEGREES BELOW
READINGS FROM 24 HOURS AGO. THIS MAY IMPACT OUR OVERNIGHT
LOWS A BIT...BUT DAY SHIFT WAS HEADED DOWN THE RIGHT PATH WITH
UNDERCUTTING MOS NUMBERS.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 308 PM MDT FRI JUL 19 2013
SHOWERS AND THUNDERSTORMS DEVELOPING FIRST OVER THE CENTRAL AND
SOUTHERN MTNS THIS AFTERNOON ARE EXPECTED TO INCREASE IN COVERAGE AS
THE DAY WEARS ON AND INSTABILITY CONTINUES BEING REALIZED. A BIT
SLOWER START TODAY LIKELY THE RESULT OF MORE MORNING CLOUDINESS AS
COMPARED TO THURSDAY. THE FLASH FLOOD WATCH REMAINS IN EFFECT FOR
ALL BUT THE NORTHERN-MOST COUNTIES...WHERE A BIT DRIER AIR WAS
WORKING IN. HOWEVER...THE HIGH-RESOLUTION HRRR MODEL AND THE NAM12
FOCUS PRECIPITATION MORE ON SE UT AND SW CO AND UP ACROSS GUNNISON
COUNTY THROUGH LATE EVENING. THIS SEEMS REASONABLE AS SATELLITE
IMAGES SHOW THE MONSOONAL MOISTURE PLUME AND ASSOCIATED
DEFORMATION ZONE LAYING OVER AND BECOMING MORE EAST-WEST ORIENTED
ACROSS THE SOUTHERN HALF OF THE FORECAST AREA. SEE HYDROLOGY
SECTION FOR ADDITIONAL INFO.
DRIER AIR WILL CONTINUE TO CIRCULATE AROUND HIGH PRESSURE CENTERED
OVER NEVADA ON SATURDAY. THE 12Z MODELS INDICATE PRECIPITABLE WATER
DROPS BELOW 0.50 INCH ACROSS OUR NORTH AND CENTRAL AREAS ON
SATURDAY...COMPARED TO 0.75 TO 1.30 VALUES FOR TODAY. THIS WILL
CONFINE SCATTERED SHOWERS AND THUNDERSTORMS TO SOUTH OF INTERSTATE
70 SATURDAY AFTERNOON. THE BEST COVERAGE WILL BE OVER THE SAN JUAN
MTNS WHERE PRECIPITABLE WATER VALUES OF OF 0.70 OR 0.80 INCH WILL
PERSIST. CONVECTION SHOULD DIE OUT BEFORE MIDNIGHT WITH THE LOSS OF
HEATING.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 308 PM MDT FRI JUL 19 2013
WARMER AND DRIER THROUGH TUESDAY THEN A RETURN OF MONSOONAL MOISTURE
BEGINNING WEDNESDAY.
GOOD MODEL AGREEMENT CONTINUES. INTO EARLY NEXT WEEK THE UPPER
HIGH REMAINS CENTERED OVER THE GREAT BASIN AND NORTHERN
CALIFORNIA...WITH AN INVERTED TROUGH IN NORTHERN BAJA. A N-NW FLOW
KEEPS DRIER AIR ACROSS DOWN TO NEAR THE FOUR CORNERS ON SUNDAY.
MODELED PRECIPITABLE WATER VALUES ARE AT OR LESS THEN 0.5 INCH FOR
MUCH OF THE CWA WITH A SHARP INCREASED GRADIENT ALONG THE NM/AZ
BORDER. SO SCATTERED SHOWERS AND STORMS WILL FAVOR THE FAR SOUTH
AND ALONG THE SOUTHERN PORTION OF THE CONTINENTAL DIVIDE.
THIS DRIER AIR REMAINS IN PLACE THROUGH TUESDAY. DIURNAL
TEMPERATURE SPREAD WILL INCREASE IN THE DRIER AIR MASS WITH THE
LOWER VALLEYS OF UTAH AND FAR WESTERN COLORADO THREATENING TRIPLE
DIGIT AFTERNOONS AGAIN. DEW POINTS IN THE 20-30S ALONG AND NORTH OF
I-70 WILL HELP EVAPORATIVE COOLERS TO WORK MORE EFFICIENTLY.
WEDNESDAY...THERE IS GOOD MODEL AGREEMENT THAT THE UPPER HIGH BEGINS
TO SHIFT TO SOUTH CENTRAL COLORADO...THEN ONTO THE SOUTHERN PLAINS
ON THURSDAY AND FRIDAY. MEANWHILE THE NORTHERN BAJA LOW BEGINS TO
LIFT NE INTO THE GREAT BASIN BRINGING SUBTROPICAL MOISTURE WITH IT.
THIS DEEPER MOISTURE AND INCREASED THUNDERSTORM POTENTIAL IS
CURRENTLY TIMED TO SPREAD INTO EASTERN UTAH WEDNESDAY IN THE FASTER
EC THEN WESTERN COLORADO ON THURSDAY AND FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY EVENING)
ISSUED AT 848 PM MDT FRI JUL 19 2013
ISOLATED THUNDERSTORMS WILL CONTINUE TO LINGER ACROSS WESTERN
COLORADO AND EASTERN UTAH THROUGH 08Z WITH LITTLE TO NO IMPACT
EXPECTED AT TERMINAL SITES. EXPECT GUSTY WINDS AND HEAVY RAIN IN
THE VICINITY OF ANY STORMS. DRIER CONDITIONS WILL CONTINUE TO WORK
BACK INTO THE REGION THROUGH SATURDAY. HOWEVER...ENOUGH MOISTURE
WILL LINGER OVER THE REGION TO TRIGGER ISOLATED TO SCATTERED
THUNDERSTORMS AFTER 18Z SATURDAY WITH STORMS PERSISTING THROUGH
03Z SUNDAY. EXPECT GUSTY WINDS TO 40 MPH AND LOCALLY HEAVY
RAINFALL WITH ANY STORMS ON SATURDAY.
&&
.HYDROLOGY...
ISSUED AT 848 PM MDT FRI JUL 19 2013
DRIER AIR CONTINUES TO OVERTAKE EASTERN UTAH AND WESTERN COLORADO
WITH STORMS FALLING APART RATHER QUICKLY THIS EVENING.
PRECIPITABLE WATER VALUES HAVE DROPPED BACK UNDER ONE INCH AND
WITH ONLY ISOLATED COVERAGE AND NO SIGNIFICANT WAVE IN THE
FLOW...HAVE WENT AHEAD AND DROPPED THE FLASH FLOOD WATCH.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
UPDATE...JDC
SHORT TERM...JAD
LONG TERM...JOE
AVIATION...JDC
HYDROLOGY...JDC
AREA FORECAST DISCUSSION...CORRECTED
NWS PUEBLO CO
740 PM MDT FRI JUL 19 2013
.UPDATE...
ISSUED AT 730 PM MDT FRI JUL 19 2013
UPDATED TO CANCEL FLASH FLOOD WATCH FOR EL PASO AND TELLER
COUNTIES. LATEST HIGHER RESOLUTION MODEL RUNS OF THE HRRR AND RAP
ARE NOT INDICATING AS MUCH UPSTREAM DEVELOPMENT AS PREVIOUS RUNS.
THIS IS SUPPORTED BY CURRENT RADARS INDICATING A ONLY FEW STORMS
IN PARK COUNTY WEST OF TARRYALL RESERVOIR...AS WELL AS A FEW MORE
STORMS ACROSS THE NORTHERN MTS OF SUMMIT...GRAND AND LARIMAR
COUNTIES AT THIS TIME. RADAR AND MODEL TRENDS HAVE THIS STORMS
MOVING SOUTH AND WEAKENING THROUGH THE REST OF THE EVENING...WITH
THE THREAT OF FLASH FLOODING DIMINISHING AS WELL.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 238 PM MDT FRI JUL 19 2013
AN UPR RIDGE WL REMAIN CENTERED OVR NV TONIGHT AND SATURDAY. A UPR
DISTURBANCE WL CONTINUE MOVING SOUTH ACRS THE FORECAST AREA
TONIGHT. THERE IS PLENTY OF MOISTURE OVER THE AREA AS WELL. ALL
THE INGREDIENTS SEEM TO BE IN PLACE TO BRING WIDESPREAD PCPN OVR AND
NR THE MTS...WITH SCT ACTIVITY OVR THE SERN PLAINS. THE STEERING
FLOW WL REMAIN FAIRLY LIGHT...RESULTING AND SLOW MOVING STORMS AND
THUS UNDER THE HEAVIER STORMS...LOCALLY HEAVY RAIN COULD FALL. THIS
BECOMES A BIG CONCERN IF IT OCCURS OVR THE BURNS SCARS AS MUD AND
ASH FLOWS COULD OCCUR. WL LEAVE THE FLASH FLOOD WATCH IN EFFECT FOR
EL PASO AND TELLER COUNTIES. AS THE UPR DISTURBANCE MOVES SOUTHWARD
OVR THE AREA...BOTH THE RAP13 AND NAM SHOW THE FOCUS OF PCPN
SHIFTING SOUTHWARD THIS EVENING OVR THE SRN MTS AND SOUTH OF HIGHWAY
50. THE HRRR ALSO SHOWS WIDESPREAD PCPN AND CHANCES FOR RAIN OVR
SRN AREAS...BUT ALSO INCREASES PCPN CHANCES OVR EL PASO...TELLER
COUNTIES AND PUEBLO COUNTIES DURING THE EVENING HOURS.
OVERNIGHT...PCPN CHANCES ARE EXPECTED TO DECREASE OR END FROM NORTH
TO SOUTH...WITH SOME LIGHT PCPN POSSIBLY LINGERING THRU THE NIGHT
OVR FAR SOUTHERN AREAS. IT LOOKS DRIER IN THE UPR LEVELS ON SATURDAY
AS THE MSTR PLUME SHIFTS SOUTH OF THE AREA...BUT THERE WL STILL BE
PLENTY OF LOW LEVEL MSTR TO WORK WITH FOR SCT TO LIKELY POPS OVR THE
MTS AND PROBABLY ISOLD TO SCT POPS OVR THE SERN PLAINS. STORMS
SHOULD BE FAIRLY SLOW MOVING AGAIN AND WE COULD SEE SOME LOCALIZED
HEAVY RAIN.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 238 PM MDT FRI JUL 19 2013
UPPER LEVEL FLOW TURNS SLIGHTLY MORE NORTHWESTERLY SUNDAY...WHICH
WILL TEND TO PUSH THE MOIST PLUME SOUTH OF THE STATE INTO NM AND
AZ BY AFTERNOON. MODELS SHOW WEAK FRONTAL BOUNDARY DISSIPATING
SOMEWHERE OVER THE ERN PLAINS OF CO...WITH DECREASING LOW LEVEL
MOISTURE AS UPSLOPE WINDS WEAKEN. SUSPECT TSRA WILL STAY ISOLATED
AND LIMITED TO MAINLY THE HIGHER TERRAIN SUN AFTERNOON AND
EVENING...AND WILL END QUICKLY BY LATE EVENING WITH LITTLE IN THE
WAY OF UPPER SUPPORT. MAX TEMPS SUN SHOULD CREEP UPWARD A DEGF OR
TWO...THOUGH 700 MB TEMPS SUGGEST RATHER HOT MET GUIDANCE MAXES
MAY BE JUST A TAD TOO WARM. SIMILAR SET-UP MON/TUE...AS WEAK
SURFACE FRONT REFORMS OVER NORTHEAST COLORADO AND AIR MASS OVER
SOUTHERN COLORADO CONTINUES TO DRY. AGAIN EXPECT ISOLATED
MOUNTAIN CONVECTION BOTH DAYS...THOUGH COVERAGE AND RAINFALL
AMOUNTS WILL BE RATHER SPARSE. 700 MB TEMPS CREEP UPWARD INTO THE
18C-20C RANGE...WHICH SHOULD PRODUCE A FEW 100F PLUS READINGS OVER
THE EASTERN PLAINS BOTH DAYS. ON WED...FRONT DROPS SOUTH OVER THE
PLAINS LEADING TO A RENEWED WESTWARD SURGE OF MOISTURE OVER THE
EASTERN MOUNTAINS AND PLAINS BY AFTERNOON. GFS AND ECMWF ARE
SIMILAR WITH SURFACE FEATURES...BUT ONLY GFS BREAKS OUT CONVECTION
THU EVENING...WHILE ECMWF STAYS DRY. WILL LEAN TOWARD THE WETTER
SOLUTION OF THE GFS FOR NOW...GIVEN THE DEEPER MOISTURE AND
INSTABILITY BEHIND THE FRONT. FARTHER WEST...LOW GRADE MONSOON
REDEVELOPS WED AS SLIGHTLY DEEPER MID LEVEL MOISTURE PUSHES BACK
INTO THE STATE...LEADING TO BETTER TSRA COVERAGE THAN MON/TUE.
PAST WED...MOISTURE LOOKS TO SLOSH BACK AND FORTH ACROSS THE
EASTERN PLAINS...WITH PERHAPS A DECREASE IN PRECIP CHANCES THU AND
AN INCREASE FRI. OVER THE MOUNTAINS...UPSWING IN CONVECTION LOOKS
POSSIBLE FRI AS WELL...ESPECIALLY AS LAST FEW MODEL RUNS OF BOTH
THE ECMWF AND GFS TRY TO BUILD THE UPPER RIDGE EASTWARD INTO
TX...ALLOWING A RENEWED INFLUX OF MOISTURE FROM THE SOUTH.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 238 PM MDT FRI JUL 19 2013
THUNDERSTORMS WILL BE POSSIBLE THROUGH THIS EVENING AT KPUB...KCOS
AND KALS...PROBABLY ENDING BY 06Z...ALTHOUGH COULD CONTINUE A BIT
LATER AT KALS. HEAVY RAIN WILL BE POSSIBLE AT THE TAF SITES WHICH
COULD BRIEFLY CAUSE MVFR/IFR CONDITIONS. OTHERWISE VFR CONDITIONS
ARE EXPECTED. ON SATURDAY THE TAFS SITES COULD AGAIN SEE SOME
SHOWERS AND THUNDERSTORMS...MAINLY AFTER 20Z.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...MW
SHORT TERM...28
LONG TERM...PETERSEN
AVIATION...28
AREA FORECAST DISCUSSION
NWS PUEBLO CO
730 PM MDT FRI JUL 19 2013
.UPDATE...
ISSUED AT 730 PM MDT FRI JUL 19 2013
UPDATED TO CANCEL FLASH FLOOD WATCH FOR EL PASO COUNTY. LATEST
HIGHER RESOLUTION MODEL RUNS OF THE HRRR AND RAP ARE NOT INDICATING
AS MUCH UPSTREAM DEVELOPMENT AS PREVIOUS RUNS WHICH IS BEING
SUPPORTED BY CURRENT RADARS INDICATING A FEW STORMS IN PARK COUNTY
WEST OF TARRYALL RESERVOIR AS WELL AS A FEW MORE STORMS ACROSS THE
NORTHERN MTS OF SUMMIT...GRAND AND LARIMAR COUNTIES AT THIS TIME.
RADAR AND MODEL TRENDS HAVE THIS STORMS MOVING SOUTH AND WEAKENING
THROUGH THE REST OF THE EVENING...WITH THE THREAT OF FLASH FLOODING
DIMINISHING AS WELL.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 238 PM MDT FRI JUL 19 2013
AN UPR RIDGE WL REMAIN CENTERED OVR NV TONIGHT AND SATURDAY. A UPR
DISTURBANCE WL CONTINUE MOVING SOUTH ACRS THE FORECAST AREA
TONIGHT. THERE IS PLENTY OF MOISTURE OVER THE AREA AS WELL. ALL
THE INGREDIENTS SEEM TO BE IN PLACE TO BRING WIDESPREAD PCPN OVR AND
NR THE MTS...WITH SCT ACTIVITY OVR THE SERN PLAINS. THE STEERING
FLOW WL REMAIN FAIRLY LIGHT...RESULTING AND SLOW MOVING STORMS AND
THUS UNDER THE HEAVIER STORMS...LOCALLY HEAVY RAIN COULD FALL. THIS
BECOMES A BIG CONCERN IF IT OCCURS OVR THE BURNS SCARS AS MUD AND
ASH FLOWS COULD OCCUR. WL LEAVE THE FLASH FLOOD WATCH IN EFFECT FOR
EL PASO AND TELLER COUNTIES. AS THE UPR DISTURBANCE MOVES SOUTHWARD
OVR THE AREA...BOTH THE RAP13 AND NAM SHOW THE FOCUS OF PCPN
SHIFTING SOUTHWARD THIS EVENING OVR THE SRN MTS AND SOUTH OF HIGHWAY
50. THE HRRR ALSO SHOWS WIDESPREAD PCPN AND CHANCES FOR RAIN OVR
SRN AREAS...BUT ALSO INCREASES PCPN CHANCES OVR EL PASO...TELLER
COUNTIES AND PUEBLO COUNTIES DURING THE EVENING HOURS.
OVERNIGHT...PCPN CHANCES ARE EXPECTED TO DECREASE OR END FROM NORTH
TO SOUTH...WITH SOME LIGHT PCPN POSSIBLY LINGERING THRU THE NIGHT
OVR FAR SOUTHERN AREAS. IT LOOKS DRIER IN THE UPR LEVELS ON SATURDAY
AS THE MSTR PLUME SHIFTS SOUTH OF THE AREA...BUT THERE WL STILL BE
PLENTY OF LOW LEVEL MSTR TO WORK WITH FOR SCT TO LIKELY POPS OVR THE
MTS AND PROBABLY ISOLD TO SCT POPS OVR THE SERN PLAINS. STORMS
SHOULD BE FAIRLY SLOW MOVING AGAIN AND WE COULD SEE SOME LOCALIZED
HEAVY RAIN.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 238 PM MDT FRI JUL 19 2013
UPPER LEVEL FLOW TURNS SLIGHTLY MORE NORTHWESTERLY SUNDAY...WHICH
WILL TEND TO PUSH THE MOIST PLUME SOUTH OF THE STATE INTO NM AND
AZ BY AFTERNOON. MODELS SHOW WEAK FRONTAL BOUNDARY DISSIPATING
SOMEWHERE OVER THE ERN PLAINS OF CO...WITH DECREASING LOW LEVEL
MOISTURE AS UPSLOPE WINDS WEAKEN. SUSPECT TSRA WILL STAY ISOLATED
AND LIMITED TO MAINLY THE HIGHER TERRAIN SUN AFTERNOON AND
EVENING...AND WILL END QUICKLY BY LATE EVENING WITH LITTLE IN THE
WAY OF UPPER SUPPORT. MAX TEMPS SUN SHOULD CREEP UPWARD A DEGF OR
TWO...THOUGH 700 MB TEMPS SUGGEST RATHER HOT MET GUIDANCE MAXES
MAY BE JUST A TAD TOO WARM. SIMILAR SET-UP MON/TUE...AS WEAK
SURFACE FRONT REFORMS OVER NORTHEAST COLORADO AND AIR MASS OVER
SOUTHERN COLORADO CONTINUES TO DRY. AGAIN EXPECT ISOLATED
MOUNTAIN CONVECTION BOTH DAYS...THOUGH COVERAGE AND RAINFALL
AMOUNTS WILL BE RATHER SPARSE. 700 MB TEMPS CREEP UPWARD INTO THE
18C-20C RANGE...WHICH SHOULD PRODUCE A FEW 100F PLUS READINGS OVER
THE EASTERN PLAINS BOTH DAYS. ON WED...FRONT DROPS SOUTH OVER THE
PLAINS LEADING TO A RENEWED WESTWARD SURGE OF MOISTURE OVER THE
EASTERN MOUNTAINS AND PLAINS BY AFTERNOON. GFS AND ECMWF ARE
SIMILAR WITH SURFACE FEATURES...BUT ONLY GFS BREAKS OUT CONVECTION
THU EVENING...WHILE ECMWF STAYS DRY. WILL LEAN TOWARD THE WETTER
SOLUTION OF THE GFS FOR NOW...GIVEN THE DEEPER MOISTURE AND
INSTABILITY BEHIND THE FRONT. FARTHER WEST...LOW GRADE MONSOON
REDEVELOPS WED AS SLIGHTLY DEEPER MID LEVEL MOISTURE PUSHES BACK
INTO THE STATE...LEADING TO BETTER TSRA COVERAGE THAN MON/TUE.
PAST WED...MOISTURE LOOKS TO SLOSH BACK AND FORTH ACROSS THE
EASTERN PLAINS...WITH PERHAPS A DECREASE IN PRECIP CHANCES THU AND
AN INCREASE FRI. OVER THE MOUNTAINS...UPSWING IN CONVECTION LOOKS
POSSIBLE FRI AS WELL...ESPECIALLY AS LAST FEW MODEL RUNS OF BOTH
THE ECMWF AND GFS TRY TO BUILD THE UPPER RIDGE EASTWARD INTO
TX...ALLOWING A RENEWED INFLUX OF MOISTURE FROM THE SOUTH.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 238 PM MDT FRI JUL 19 2013
THUNDERSTORMS WILL BE POSSIBLE THROUGH THIS EVENING AT KPUB...KCOS
AND KALS...PROBABLY ENDING BY 06Z...ALTHOUGH COULD CONTINUE A BIT
LATER AT KALS. HEAVY RAIN WILL BE POSSIBLE AT THE TAF SITES WHICH
COULD BRIEFLY CAUSE MVFR/IFR CONDITIONS. OTHERWISE VFR CONDITIONS
ARE EXPECTED. ON SATURDAY THE TAFS SITES COULD AGAIN SEE SOME
SHOWERS AND THUNDERSTORMS...MAINLY AFTER 20Z.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...MW
SHORT TERM...28
LONG TERM...PETERSEN
AVIATION...28
AREA FORECAST DISCUSSION
NWS PUEBLO CO
325 PM MDT THU JUL 18 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 323 PM MDT THU JUL 18 2013
MAIN CONCERN IS THE POTENTIAL FOR HEAVY RAIN MAINLY ON FRIDAY. THIS
AFTERNOON...WATER VAPOR IMAGERY IS SHOWING THE MSTR PLUME MAINLY OVR
FAR WRN CO...BUT PLENTY OF SHOWERS AND TSTMS HAVE POPPED UP ALONG
THE CONTDVD. SOME OF THE STORMS HAVE BRIEFLY BEEN STRONG...LIKELY
PRODUCING SMALL HAIL AND HEAVY RAIN. OVR THE ERN MTS...SO FAR THERE
HAVE ONLY BEEN SOME ISOLD STORMS. STEERING FLOW ALOFT IS EASTERLY
AND THUS THE STORMS ARE MOVING TOWARD THE WEST. NOT EXPECTING
CONVECTION TO DEVELOP OVR THE SERN PLAINS...BUT LOCATIONS ALONG THE
I-25 CORRIDOR WILL PROBABLY SEE SOME ACTIVITY THIS EVENING. THE NAM
HAS BEEN CONSISTENT IS SHOWING SCT PCPN DEVELOPING THIS EVENING OVR
EL PASO AND PUEBLO COUNTIES...WHILE THE HRRR AND RAP13 SHOW ONLY
SOME ISOLD ACTIVITY. THERE IS THE POTENTIAL THIS EVENING FOR
STRONGER STORMS TO PRODUCE HEAVY RAIN...SO WL HAVE TO KEEP AN EYE ON
ANYTHING THE DEVELOPS OR MOVES OVR THE ANY OF THE BURN SCARS. AFTER
MIDNIGHT THERE COULD BE JUST SOME ISOLD SHOWERS/TSTMS LINGERING THRU
THE NIGHT IN A FEW AREAS...BUT THE CENTRAL MTS...TELLER...EL
PASO...FREMONT AND PUEBLO COUNTIES WL HAVE THE BEST CHANCES OF
SEEING SOME LINGERING CONVECTION.
MODELS SHOWING A SFC LOW DEVELOPING OVR THE SE CORNER OF
CO...CAUSING THE SFC WINDS TO BE NORTHEASTERLY UPSLOPE...AND LOW
LEVEL MSTR WL BE IN PLACE AS WELL. MODELS ARE STILL CONSISTENT
ON DEVELOPING PCPN IN THE MORNING HOURS OF FRI ALONG THE I-25
CORRIDOR AND THE HYR TRRN...WITH SOME ACTIVITY OVR THE FAR SERN
PLAINS BY LATE AFTERNOON. PRECIPITABLE WATER VALUES ARE NOT
FORECAST TO BE AS HIGH FOR FRI AS WHAT THEY WERE SHOWING THE LAST
COUPLE DAYS FOR FRI...AND NOT AS HIGH AS THEY WERE WHEN THERE WAS
FLASH FLOODING LAST WEEKEND. HOWEVER...THERE WILL STILL BE THE
POTENTIAL FOR LOCALLY HEAVY RAIN WITH STRONGER STORMS ON FRI AND
THUS FLASH FLOODING IS STILL A CONCERN...ESPECIALLY OVR THE BURN
SCARS. THE FLOW ALOFT ON FRI WL BE NORTH TO NORTHEAST AND THUS
STORMS ARE EXPECTED TO MOVE TOWARD THE SOUTH OR SOUTHWEST.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 323 PM MDT THU JUL 18 2013
LONGER TERM METEOROLOGICAL CHALLENGES INCLUDES POPS AND
TEMPERATURES. FRIDAY NIGHT INTO SATURDAY SATURDAY SHOULD
EXPERIENCE CONTINUED ELEVATED POPS(ESPECIALLY OVER SOUTHERN AND
WESTERN SECTIONS) AS WELL AS NEAR SEASONAL TEMPERATURES BEFORE
SOMEWHAT WARMER AND DRIER CONDITIONS DEVELOP OVER THE FORECAST
DISTRICT FROM LATER IN THE WEEKEND INTO NEXT WEEK.
LATEST LONGER TERM COMPUTER SIMULATIONS AND FORECAST SOUNDINGS
INDICATE THAT ROUNDS OF BASICALLY SCATTERED SHOWERS AND
THUNDERSTORMS CAPABLE OF PRODUCING LOCALLY HEAVY RAIN AND BURN
SCAR ISSUES(ESPECIALLY OVER WESTERN AND SOUTHERN SECTIONS) WILL BE
POSSIBLE FROM FRIDAY NIGHT INTO SATURDAY NIGHT IN WAKE OF
NORTHERLY SURGE ALLOWING INCREASED ATMOSPHERIC MOISTURE/PRECIPITABLE
WATER VALUES. WFO PUEBLO WILL CONTINUE TO MONITOR CLOSELY.
THEN...A DEVELOPING RIDGE OF HIGH PRESSURE INITIALLY CENTERED OVER
WESTERN NEVADA AT 00Z MONDAY IS PROJECTED TO BECOME CENTERED OVER
SOUTHERN COLORADO BY 00Z THURSDAY BEFORE SHIFTING SOUTHEAST INTO
THE TEXAS PANHANDLE BY 00Z FRIDAY.
AS THIS OCCURS...ANTICIPATE THAT POPS WILL BECOME MORE ISOLATED
FROM SUNDAY INTO NEXT WEEK IN COMBINATION WITH WARMER TEMPERATURES.
SPEAKING OF TEMPERATURES...NEAR SEASONAL MAXIMUM TEMPERATURES ARE
ANTICIPATED SATURDAY WITH ABOVE SEASONAL MAXIMUM TEMPERATURES THEN
PROJECTED OVER THE FORECAST DISTRICT FROM SUNDAY INTO THURSDAY.
MAXIMUM TEMPERATURES OVER PORTIONS OF THE SOUTHEASTERN PLAINS MAY
CHALLENGE THE CENTURY MARK AT TIMES...ESPECIALLY FROM MONDAY INTO
THURSDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 323 PM MDT THU JUL 18 2013
EXPECTING VFR CONDITIONS AT KPUB...KCOS AND KALS THROUGH THE
PERIOD. THERE COULD BE SOME SHOWERS/TSTMS IN THE VCNTY OF KCOS AND
KALS AFTER 23Z...AND POSSIBLY NR KPUB AFTER 02Z. SHOWER/TSTM
ACTIVITY SHOULD END AT THE TERMINAL SITE BY 06Z. IT LOOKS LIKE AN
EARLY SHOW IN FRIDAY...WITH THE POTENTIAL FOR SHOWERS/TSTMS AT THE
TAF SITES MAINLY AFTER 15Z. ON FRI THERE COULD BE SOME BRIEF HEAVY
RAIN AT THE TAF SITES WHICH COULD CAUSE MVFR/IFR CONDITIONS.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
319 PM MDT THU JUL 18 2013
.SHORT TERM...SLOW MOVING THUNDERSTORMS AN ISSUE OVER LARIMER
COUNTY THIS AFTN. FLASH FLOODING REPORTED IN THE FERN LAKE BURN
SCAR THIS AFTN WHERE RADAR ESTIMATED 1.5 TO 2.5 INCH STORM TOTALS.
SIMILAR ISSUES WILL CONTINUE THE REST THE AFTERNOON AND EVENING
ESPECIALLY IN THE FOOTHILLS OF LARIMER AND BOULDER COUNTIES. STORM
MOTIONS 10 KTS OR LESS THIS AFTN WITH PW VALUES CLOSE TO ONE INCH.
16Z HRRR KEEPS THE BEST CONVERAGE ALONG AND NORTH OF INTERSTATE
70 AND 76 TONIGHT...SO WILL GO WITH THE HIGHEST COVERAGE THERE. ON
FRIDAY IT WILL BE COOLER FOLLOWING THE PASSAGE OF A COLD FRONT
TONIGHT. SPATIAL CROSS SECTIONS SHOW A DEEPER EASTERLY FLOW WITH
SIMILAR PW VALUES FOR FRIDAY AFTN. AS A RESULT...SLOW MOVING
THUNDERSTORMS WITH HEAVY RAIN AND FLASH FLOODING WILL AGAIN BE AN
ISSUE ESPECIALLY IN THE BURN AREAS...BUT IN OTHER POOR DRAINAGE
AREAS AS WELL. NO FLASH FLOOD WATCH AT THIS TIME...BUT ONE MAY
BE NEEDED FOR FRIDAY AT SOME POINT.
.LONG TERM...ONLY MINOR CHANGES TODAY. UPPER RIDGE REMAINS OVER
MOST OF THE COUNTRY. DRIER AIR WORKS IN FROM THE NORTHWEST ON
SUNDAY FOR WARMER AND NEARLY DRY WEATHER...THEN BY LATE IN THE
WEEK MOISTURE COMES UP FROM THE SOUTH AGAIN. THIS IS ALREADY
COVERED WELL...MINOR CHANGES IN MODEL CONSENSUS LOOK FINE.
&&
.AVIATION...16Z HRRR MDL WANT TO KEEP THE HIGHEST TSTM COVERAGE
TO THE NORTH AND WEST OF DENVER THIS EVENING SO IT MAY BE BEST TO
GO WITH VCTS THIS AFTN SO HOLD OFF ON THE TEMPO GROUP FOR TSTMS
FOR THE 00Z TAFS. WILL WATCH THE NEXT COUPLE OF HRRR RUNS AND SEE
HOW THEY HANDLE OUTFLOW BOUNDARIES AND THE CONSEQUENT CONVECTION
OFF THE FOOTHILLS BEFORE MAKING A DECISION. A COOLER AMS WILL BE
OVER THE AREA ON FRIDAY FOLLOWING THE COLD FRONT TONIGHT. FLOW AT
THE SFC AND ALOFT WILL BE EASTERLY FOR FRIDAY AFTN...WITH A BETTER
CHANCE OF TSTMS WEST OF INTERSTATE 25.
&&
.HYDROLOGY...THREAT FOR FLASH FLOODING WILL BE AN ISSUE IN THROUGH
04Z THIS EVENING...WITH ANOTHER POSSIBILITY FOR FLASH FLOODING IN
THE BURN AREAS FRIDAY AFTN. STORM MOTIONS A LITTLE ERRATIC THIS
AFTN WITH SPEEDS OF 6-10KTS...WITH SLOW MOVEMENT AGAIN EXPECTED
FRIDAY AFTN WITH STORM MOTION EXPECTED TO BE NE TO SW.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...COOPER
LONG TERM....GIMMESTAD
AVIATION...COOPER
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
955 AM MDT THU JUL 18 2013
.UPDATE...I DECIDED TO INCREASE THE POPS ALONG THE URBAN CORRIDOR
LATE THIS AFTN AND EVENING. STILL SCATTERED IN TERMS OF COVERAGE
BUT SLIGHTLY HIGHER POPS.
&&
.PREV DISCUSSION... /ISSUED 905 AM MDT THU JUL 18 2013/
UPDATE...CURRENT FORECAST LOOKS ON TRACK SO NO CHANGES PLANNED AT
THIS TIME.
&&
.AVIATION...LATEST HRRR INDICATE TSTMS DEVELOPING OVER THE DENVER
AREA AROUND 22Z-04Z WINDOW. ALL THE MDLS GENERATE A PERIOD OF QPF
OVER THE DENVER AREA AT THAT TIME. PLENTY OF MOISTURE AND INSTBY
AROUND SO OPTED TO ADD VCTS FOR THIS TIME FRAME WITH A TEMPO GROUP
FOR TSRA AS WELL. PULSE TYPE THUNDERSTORMS WITH MODERATE TO HEAVY
RAIN THE MAIN THREAT...COULD SEE BRIEF PERIOD OF MVFR CIGS/VSBYS
IN THE HEAVIER RAIN SHOWERS. OTHERWISE NO OTHER CHANGES TO THE
REST OF THE TAF AT THIS TIME.
.PREV DISCUSSION... /ISSUED 354 AM MDT THU JUL 18 2013/
SHORT TERM...PRECIPITABLE WATER VALUES HAVE INCREASED 0.10 TO
0.25 INCH FROM 24 HOURS AGO...WITH VALUES AROUND 1.0 INCH ALONG
THE FRONT RANGE. MOISTURE SHOULD CONTINUE TO SLOWLY INCREASE
THROUGH THE AFTERNOON/TONIGHT AS UPPER LEVEL MOISTURE PLUME SHIFTS
EAST/SOUTHEAST FROM WYOMING/NORTHWEST COLORADO. AIRMASS WARMS
ENOUGH IN THE LOW LEVELS TO BREAK INVERSIONS IN THE MOUNTAINS BY
LATE THIS MORNING AND THEN ON THE PLAINS BY MID/LATE AFTERNOON.
MOST SHORT RANGE MODELS SUGGEST A CONVERGENCE ZONE FROM STALLING
SURFACE TROUGH WILL SET UP FROM NEAR THE PALMER DIVIDE NORTHEAST
ACROSS THE PLAINS BY LATE AFTERNOON WHICH WOULD AID LOW LEVEL
MOISTURE CONVERGENCE AND STORM DEVELOPMENT AS WELL. CAPES ARE
LIMITED TO LESS THAN 1000 J/KG AND LITTLE IF ANY SHEAR SO EXPECT
PULSE OUTFLOW DOMINATED STORMS. THEY WILL STILL PRODUCE BRIEF VERY
HEAVY RAIN DUE TO INCREASED PRECIPITABLE WATER.
TEMPERATURES ON THE PLAINS WILL STILL BE A FEW DEGREES WARMER
THAN YESTERDAY DESPITE THE INCREASE IN CLOUD COVER BY THIS
AFTERNOON.
FOR LATER TONIGHT...STORM THREAT WILL GRADUALLY DIMINISH AS
AIRMASS STABILIZES. THERE IS STILL WEAK Q-G LIFT NOTED SO CANT
TOTALLY RULE OUT A STORM OR TWO LINGERING PAST MIDNIGHT.
LONG TERM...THE SURFACE LOW WILL CONTINUE MOVING SOUTH INTO
SOUTHEASTERN COLORADO FRIDAY ALLOWING SURFACE WINDS TO BECOME
NORTHEASTERLY UPSLOPE. WITH PRECIPITABLE WATER VALUES OF 1-1.25
INCHES ACROSS THE PLAINS AND 0.7-1 INCH OVER THE HIGHER
TERRAIN...EXPECTING NUMEROUS SHOWERS AND THUNDERSTORMS OVER THE
EASTERN FRONT RANGE MOUNTAINS AND FOOTHILLS AND AT LEAST SCATTERED
COVERAGE OVER THE PLAINS. THESE STORMS WILL BE ABLE TO PRODUCE
BRIEF HEAVY RAIN...SO WILL HAVE TO KEEP AN EYE ON THE FOOTHILLS
AND OLD BURN SCARS. TEMPERATURES FRIDAY WILL BE ABOUT 5-10 DEGREES
COOLER THAN TODAYS READINGS.
ON SATURDAY...A LITTLE EXTRA PUSH OF MOISTURE FROM THE EAST WILL
ALLOW A THETA E RIDGE TO MOVE OVER THE PLAINS AND PRODUCE ANOTHER
DAY OF SCATTERED THUNDERSTORMS. HOWEVER THESE WILL BE SLIGHTLY
DRIER AND SHOULD DIE OFF LATER IN THE EVENING AS DRIER AIR MOVES
IN FROM THE NORTH. TEMPERATURES SATURDAY WILL WARM A COUPLE
DEGREES...HOWEVER IT MAY BE VERY SIMILAR TO FRIDAY DEPENDING ON
CLOUD COVER.
SUNDAY AND MONDAY WILL FEATURE WARMER AND MOSTLY DRY WEATHER AS
THE UPPER RIDGE WHICH HAD BEEN PUSHED WEST OVER CALIFORNIA BUILDS
BACK EAST. THIS WILL BRING TEMPERATURES BACK TO AND ABOVE NORMALS
FOR MID TO LATE JULY. MODELS THEN SHOW A WEAK SHORTWAVE TROUGH TO
DROP OUT OF THE PACIFIC NORTHWEST FOR TUESDAY AND WEDNESDAY. THIS
WILL BRING COOLER AND WETTER WEATHER FOR THESE DAYS...WITH SHOWERS
MAINLY OVER THE HIGH TERRAIN TUESDAY THEN SPREADING OVER THE
PLAINS WEDNESDAY.
AVIATION...VFR CONDITIONS WILL PERSIST THROUGH TONIGHT. WINDS
WILL TURN LIGHT WEST/NORTHWEST BY 15Z-17Z THIS MORNING AND THEN
MORE NORTHERLY BY AFTERNOON. SOME GUSTS TO 20 KTS POSSIBLE AFTER
18Z. STORM CHANCES WILL BE HIGHER TODAY...PROBABLY ENOUGH TO
WARRANT AT LEAST A TEMPO GROUP FOR GUSTY OUTFLOW WINDS TO 30-40
KTS. MAIN THREAT WOULD BE 21Z-04Z. SLIGHT CHANCE OF A STRONG
ENOUGH STORM MOVING DIRECTLY OVER THE AIRPORT TO REDUCE VSBYS
TO 3-4SM.
HYDROLOGY...PRECIPITABLE WATER VALUES HAVE ALREADY INCREASED TO
AROUND 1.0 INCH ALONG THE FRONT RANGE. SEE THESE VALUES INCREASING
SLIGHTLY THROUGH THE DAY. AS A RESULT...LOCALLY HEAVY RAIN
POSSIBLE WITH ALL STORMS ESPECIALLY SINCE THEY WILL BE SLOW
MOVING. HOWEVER...WARM CLOUD DEPTH IS LIMITED TO JUST A COUPLE
THOUSAND FEET GIVEN HIGH FREEZING LEVELS...AND RELATIVELY DEEP
SUBCLOUD LAYER WILL LIKELY RESULT IN OUTFLOW DOMINATED STORMS.
MAIN THREAT FOR ANY FLOODING CONCERNS WILL BE IN THE FRONT RANGE
BURN SCARS...SO WILL HAVE TO MONITOR THOSE CLOSELY THIS
AFTERNOON/EVENING. THREAT LOW ENOUGH TO PRECLUDE A FLASH FLOOD
WATCH AT THIS TIME...BUT WILL HIGHLIGHT LOCALLY HEAVY RAINFALL IN
HAZARDOUS WEATHER OUTLOOK.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...COOPER
LONG TERM....KRIEDERMAN
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
905 AM MDT THU JUL 18 2013
.UPDATE...CURRENT FORECAST LOOKS ON TRACK SO NO CHANGES PLANNED AT
THIS TIME.
&&
.AVIATION...LATEST HRRR INDICATE TSTMS DEVELOPING OVER THE DENVER
AREA AROUND 22Z-04Z WINDOW. ALL THE MDLS GENERATE A PERIOD OF QPF
OVER THE DENVER AREA AT THAT TIME. PLENTY OF MOISTURE AND INSTBY
AROUND SO OPTED TO ADD VCTS FOR THIS TIME FRAME WITH A TEMPO GROUP
FOR TSRA AS WELL. PULSE TYPE THUNDERSTORMS WITH MODERATE TO HEAVY
RAIN THE MAIN THREAT...COULD SEE BRIEF PERIOD OF MVFR CIGS/VSBYS
IN THE HEAVIER RAIN SHOWERS. OTHERWISE NO OTHER CHANGES TO THE
REST OF THE TAF AT THIS TIME.
&&
.PREV DISCUSSION... /ISSUED 354 AM MDT THU JUL 18 2013/
SHORT TERM...PRECIPITABLE WATER VALUES HAVE INCREASED 0.10 TO
0.25 INCH FROM 24 HOURS AGO...WITH VALUES AROUND 1.0 INCH ALONG
THE FRONT RANGE. MOISTURE SHOULD CONTINUE TO SLOWLY INCREASE
THROUGH THE AFTERNOON/TONIGHT AS UPPER LEVEL MOISTURE PLUME SHIFTS
EAST/SOUTHEAST FROM WYOMING/NORTHWEST COLORADO. AIRMASS WARMS
ENOUGH IN THE LOW LEVELS TO BREAK INVERSIONS IN THE MOUNTAINS BY
LATE THIS MORNING AND THEN ON THE PLAINS BY MID/LATE AFTERNOON.
MOST SHORT RANGE MODELS SUGGEST A CONVERGENCE ZONE FROM STALLING
SURFACE TROUGH WILL SET UP FROM NEAR THE PALMER DIVIDE NORTHEAST
ACROSS THE PLAINS BY LATE AFTERNOON WHICH WOULD AID LOW LEVEL
MOISTURE CONVERGENCE AND STORM DEVELOPMENT AS WELL. CAPES ARE
LIMITED TO LESS THAN 1000 J/KG AND LITTLE IF ANY SHEAR SO EXPECT
PULSE OUTFLOW DOMINATED STORMS. THEY WILL STILL PRODUCE BRIEF VERY
HEAVY RAIN DUE TO INCREASED PRECIPITABLE WATER.
TEMPERATURES ON THE PLAINS WILL STILL BE A FEW DEGREES WARMER
THAN YESTERDAY DESPITE THE INCREASE IN CLOUD COVER BY THIS
AFTERNOON.
FOR LATER TONIGHT...STORM THREAT WILL GRADUALLY DIMINISH AS
AIRMASS STABILIZES. THERE IS STILL WEAK Q-G LIFT NOTED SO CANT
TOTALLY RULE OUT A STORM OR TWO LINGERING PAST MIDNIGHT.
LONG TERM...THE SURFACE LOW WILL CONTINUE MOVING SOUTH INTO
SOUTHEASTERN COLORADO FRIDAY ALLOWING SURFACE WINDS TO BECOME
NORTHEASTERLY UPSLOPE. WITH PRECIPITABLE WATER VALUES OF 1-1.25
INCHES ACROSS THE PLAINS AND 0.7-1 INCH OVER THE HIGHER
TERRAIN...EXPECTING NUMEROUS SHOWERS AND THUNDERSTORMS OVER THE
EASTERN FRONT RANGE MOUNTAINS AND FOOTHILLS AND AT LEAST SCATTERED
COVERAGE OVER THE PLAINS. THESE STORMS WILL BE ABLE TO PRODUCE
BRIEF HEAVY RAIN...SO WILL HAVE TO KEEP AN EYE ON THE FOOTHILLS
AND OLD BURN SCARS. TEMPERATURES FRIDAY WILL BE ABOUT 5-10 DEGREES
COOLER THAN TODAYS READINGS.
ON SATURDAY...A LITTLE EXTRA PUSH OF MOISTURE FROM THE EAST WILL
ALLOW A THETA E RIDGE TO MOVE OVER THE PLAINS AND PRODUCE ANOTHER
DAY OF SCATTERED THUNDERSTORMS. HOWEVER THESE WILL BE SLIGHTLY
DRIER AND SHOULD DIE OFF LATER IN THE EVENING AS DRIER AIR MOVES
IN FROM THE NORTH. TEMPERATURES SATURDAY WILL WARM A COUPLE
DEGREES...HOWEVER IT MAY BE VERY SIMILAR TO FRIDAY DEPENDING ON
CLOUD COVER.
SUNDAY AND MONDAY WILL FEATURE WARMER AND MOSTLY DRY WEATHER AS
THE UPPER RIDGE WHICH HAD BEEN PUSHED WEST OVER CALIFORNIA BUILDS
BACK EAST. THIS WILL BRING TEMPERATURES BACK TO AND ABOVE NORMALS
FOR MID TO LATE JULY. MODELS THEN SHOW A WEAK SHORTWAVE TROUGH TO
DROP OUT OF THE PACIFIC NORTHWEST FOR TUESDAY AND WEDNESDAY. THIS
WILL BRING COOLER AND WETTER WEATHER FOR THESE DAYS...WITH SHOWERS
MAINLY OVER THE HIGH TERRAIN TUESDAY THEN SPREADING OVER THE
PLAINS WEDNESDAY.
AVIATION...VFR CONDITIONS WILL PERSIST THROUGH TONIGHT. WINDS
WILL TURN LIGHT WEST/NORTHWEST BY 15Z-17Z THIS MORNING AND THEN
MORE NORTHERLY BY AFTERNOON. SOME GUSTS TO 20 KTS POSSIBLE AFTER
18Z. STORM CHANCES WILL BE HIGHER TODAY...PROBABLY ENOUGH TO
WARRANT AT LEAST A TEMPO GROUP FOR GUSTY OUTFLOW WINDS TO 30-40
KTS. MAIN THREAT WOULD BE 21Z-04Z. SLIGHT CHANCE OF A STRONG
ENOUGH STORM MOVING DIRECTLY OVER THE AIRPORT TO REDUCE VSBYS
TO 3-4SM.
HYDROLOGY...PRECIPITABLE WATER VALUES HAVE ALREADY INCREASED TO
AROUND 1.0 INCH ALONG THE FRONT RANGE. SEE THESE VALUES INCREASING
SLIGHTLY THROUGH THE DAY. AS A RESULT...LOCALLY HEAVY RAIN
POSSIBLE WITH ALL STORMS ESPECIALLY SINCE THEY WILL BE SLOW
MOVING. HOWEVER...WARM CLOUD DEPTH IS LIMITED TO JUST A COUPLE
THOUSAND FEET GIVEN HIGH FREEZING LEVELS...AND RELATIVELY DEEP
SUBCLOUD LAYER WILL LIKELY RESULT IN OUTFLOW DOMINATED STORMS.
MAIN THREAT FOR ANY FLOODING CONCERNS WILL BE IN THE FRONT RANGE
BURN SCARS...SO WILL HAVE TO MONITOR THOSE CLOSELY THIS
AFTERNOON/EVENING. THREAT LOW ENOUGH TO PRECLUDE A FLASH FLOOD
WATCH AT THIS TIME...BUT WILL HIGHLIGHT LOCALLY HEAVY RAINFALL IN
HAZARDOUS WEATHER OUTLOOK.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...COOPER
LONG TERM....KRIEDERMAN
AVIATION...COOPER
AREA FORECAST DISCUSSION
NWS TAUNTON MA
956 PM EDT FRI JUL 19 2013
.SYNOPSIS...
HIGH PRESSURE NEAR BERMUDA WILL CONTINUE TO CIRCULATE HOT AND
HUMID CONDITIONS INTO SOUTHERN NEW ENGLAND THROUGH SATURDAY.
SCATTERED THUNDERSTORMS ARE EXPECTED SATURDAY AFTERNOON AND
EVENING AS A COLD FRONT APPROACHES FROM THE GREAT LAKES. STORMS
WILL BE MOST NUMEROUS ACROSS WESTERN PORTIONS OF CONNECTICUT AND
MASSACHUSETTS ALONG WITH A FEW BECOMING STRONG TO SEVERE. RELIEF
FROM THE HEAT AND HUMIDITY WILL ARRIVE SUNDAY AND CONTINUE THROUGH
THE REST OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
950 PM UPDATE...
IT REMAINS VERY UNSTABLE FOR THIS TIME OF THE EVENING WITH
MLCAPES STILL 2000-3000 J/KG. WATCHING AN ORGANIZED CLUSTER OF
STRONG TO SEVERE STORMS MOVING EAST FROM UPSTATE NY AND
APPROACHING OUR NW ZONES. THIS ACTIVITY IS FIRING WHERE MID LEVEL
TEMPS ARE ABOUT 2C COOLER. IN ADDITION DEEPER MOISTURE IS A BIT
LESS ACROSS SNE. SO THIS LEADS US TO BELIEVE WE SHOULD SEE A
GRADUAL WEAKENING TREND AS THESE STORMS APPROACH NW MA AND S NH.
THE HRRR CONTINUES TO INDICATE WEAKENING CONVECTION WILL AFFECT
OUR NW ZONES DURING THE NEXT 1-2 HOURS BUT CANT RULE OUT A STRONG
STORM WITH GUSTY WINDS. WILL MONITOR CLOSELY. KEPT CHC POPS ACROSS
NW ZONES UNTIL JUST AFTER MIDNIGHT.
OTHERWISE...A DRY BUT WARM NIGHT ACROSS THE REST OF SOUTHERN NEW
ENGLAND. LOWS WILL ONLY BOTTOM OUT IN THE 70S AND DOWNTOWN BOSTON
MAY NOT DROP BELOW 80!
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
*** STRONG TO SEVERE TSTMS LIKELY SAT ESP WESTERN NEW ENG ***
SATURDAY...
FORECAST THEME REMAINS THE SAME...NOT AS HOT AS TODAY BUT HIGHS
STILL IMPRESSIVE WITH MAXS IN THE LOW TO MID 90S AWAY FROM THE
SOUTH COAST. HUMIDITY WILL REMAIN HIGH WITH DEW PTS IN THE U60S TO
L70S. THEREFORE HAVE ISSUED A HEAT ADVISORY FOR MUCH OF
CT/RI/EASTERN MA AND SOUTHEAST NH FOR HEAT INDICES OF 100-104 SAT
AFTN.
AS FOR CONVECTION...TEMPS REMAIN WARM ALOFT BUT THIS SHOULD BE
OFFSET BY MODEST SYNOPTIC SCALE LIFT AS MID LEVEL FLOW BECOMES
CYCLONIC AND RRQ OF UPPER JET STREAK SLIDES ACROSS NY AND NEW
ENGLAND LATER IN THE DAY. PREFRONTAL TROUGH CONVERGENCE SHOULD AID
DEVELOPMENT. THIS FORCING FOR ASCENT SHOULD YIELD A STRONG
RESPONSE GIVEN MAGNITUDE OF INSTABILITY WITH ENSEMBLE MEAN CAPES
OF 1200-1800J/KG ACROSS SOUTHERN NEW ENGLAND. DEEP LAYER SHEAR
INCREASES TO 30-35 KT BY LATE AFTN ACROSS WESTERN NEW ENGLAND.
THIS WILL BE SUFFICIENT TO ORGANIZE CONVECTION INTO MULTICELLULAR
LINE SEGMENTS. STRONGEST FORCING AND WIND FIELDS ARE ACROSS
WESTERN NEW ENGLAND...THEREFORE PROBABILITY OF STRONG TO SEVERE
TSTMS IS ACROSS THIS REGION. ELSEWHERE CONVECTION MAY NOT BE AS
WIDESPREAD...MORE SCATTERED OR ISOLATED ESPECIALLY SOUTHEAST MA.
MAIN HAZARDS WITH STORMS WILL BE STRONG/DAMAGING WINDS AND HEAVY
RAINFALL WITH PWATS OF +2 STD.
SATURDAY NIGHT...
TSTMS WILL DISSIPATE FROM NW TO SE WITH SUNSET BUT MAY LINGER
ALONG THE SOUTH COAST AS THE FRONTAL BOUNDARY IS SLOW TO EXIT.
POST FRONTAL AIRMASS OVERSPREADS THE REGION FROM NW TO SE WITH A
VERY NOTICEABLE CHANGE IN THE FORM OF LOWER HUMIDITY AND COOLER
TEMPS. THIS MAY BE DELAYED UNTIL SUNDAY ALONG THE SOUTH COAST
GIVEN THE SLOWER FRONTAL DEPARTURE.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
HEADLINES...
* RELIEF FROM HEAT AND HUMIDITY SUN AND MON W/MAINLY DRY WEATHER
* SCT SHOWERS/THUNDERSTORMS MON NIGHT THROUGH FRI BUT NOT A WASHOUT
* SHOWERS/THUNDERSTORMS MAY BE MOST WIDESPREAD ON TUE
* NOT EXPECTING EXCESSIVE HEAT TO RETURN NEXT WEEK
DETAILS...
SUNDAY AND MONDAY... RELIEF FINALLY ARRIVES FROM THE EXCESSIVE HEAT
AND HUMIDITY AS HIGH PRESSURE BUILDS IN FROM THE NORTH BEHIND THE
COLD FRONT. LOW RISK FOR A FEW LEFT OVER SHOWERS SUNDAY MORNING
NEAR THE SOUTH COAST. OTHERWISE...DRY WEATHER DOMINATES WITH
COMFORTABLE HUMIDITY LEVELS. HIGH TEMPS WILL STILL BE WELL INTO THE
80S ACROSS MOST LOCATIONS WITH AT LEAST PARTIAL SUNSHINE. IT WILL
BE A BIT COOLER ALONG THE IMMEDIATE COAST WITH ONSHORE FLOW...BUT
HIGHS SHOULD STILL REACH INTO THE UPPER 70S TO LOWER 80S.
MONDAY NIGHT AND WEDNESDAY... UPPER LEVEL TROUGH DEVELOPING ACROSS
THE NORTHERN GREAT LAKES WILL SEND A COUPLE OF SHORTWAVES AT US IN
WEST TO SOUTHWEST FLOW ALOFT. TIMING IS UNCERTAIN BUT THERE WILL BE
THE THREAT OF SCATTERED SHOWERS AND THUNDERSTORMS AT TIMES...BUT NOT
EXPECTING A WASHOUT OVER THE ENTIRE PERIOD. SOME MODEL INDICATIONS
ARE THAT THE ACTIVITY MAY BE MOST WIDESPREAD ON TUE...WHERE WE WENT
WITH SOME LOW END LIKELY POPS FOR MUCH OF THE REGION. THE OVERALL
SEVERE WEATHER POTENTIAL APPEARS LOW GIVEN LIMITED INSTABILITY.
HOWEVER...HIGH PWATS WILL RESULT IN THE POTENTIAL FOR LOCALIZED
HEAVY RAINFALL WITH THE ACTIVITY.
AS FOR TEMPERATURES....THE UPPER LEVEL RIDGE OVER THE ATLANTIC WILL
BE FURTHER EAST THAN WHAT WE HAVE SEEN THIS WEEK.
THEREFORE...EXCESSIVE HEAT IS NOT EXPECTED AND HIGH TEMPERATURES
WILL BE FAIRLY SEASONABLE FOR LATE JULY.
THURSDAY AND FRIDAY... THE UPPER LEVEL TROUGH WILL REMAIN ANCHORED
ACROSS THE UPPER GREAT LAKES PLACING US IN SOUTHWEST FLOW ALOFT.
WHILE THE ENTIRE PERIOD WILL NOT BE A WASHOUT...SOUTHWEST FLOW ALOFT
WILL ALLOW ADDITIONAL SHORTWAVES TO TRACK INTO OUR REGION AT TIMES.
WILL CONTINUE CHANCE POPS FOR SHOWERS AND EMBEDDED THUNDERSTORMS.
LOW CONFIDENCE ON THE EXACT TIMING. TEMPS WILL REMAIN FAIRLY
SEASONABLE AND NOT EXPECTING A RETURN TO EXCESSIVE HEAT.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
MODERATE CONFIDENCE THROUGH SATURDAY NIGHT...
TONIGHT...WIDESPREAD MVFR/IFR CONDITIONS IN STRATUS/FOG SHOULD BE
CONFINED TO SOUTH COAST GIVEN WSW WINDS. HOWEVER...SOME HAZE AND
PATCHY FOG MAY RESULT IN OTHER LOCATIONS DROPPING BRIEFLY TO MVFR
FOR A FEW HOURS LATE TONIGHT. MAINLY A DRY NIGHT...BUT A FEW
SHOWERS/THUNDERSTORMS COULD GRAZE NORTHWEST MA/SOUTHWEST NH AFTER 10
OR 11 PM.
SAT...STRONG TSTMS LIKELY DURING THE AFTERNOON AND EARLY EVENING
FROM WEST TO EAST WITH GUSTY WINDS AND HEAVY RAIN THE MAIN THREATS.
SAT NIGHT...TSTMS MOVE OFFSHORE BUT MAY BE SLOW TO EXIT THE
IMMEDIATE SOUTH COAST INCLUDING CAPE COD AND THE ISLANDS.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF. SW WIND GUSTS TO 25 KT.
MVFR/IFR CONDITIONS IN STRATUS/FOG SHOULD REMAIN SOUTH OF THE
AIRPORT TONIGHT. STRONG STORMS LIKELY TOMORROW FROM ABOUT 19Z-00Z.
GUSTY WINDS AND HEAVY RAIN MAIN THREATS.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF. ISOLATED TSTM POSSIBLE
INTO THIS EVENING. OTHERWISE DRY/VFR. PATCHY MVFR POSSIBLE TONIGHT
IN FOG. STRONG TSTMS LIKELY TOMORROW FROM 18Z-00Z WITH GUSTY WINDS
AND HEAVY RAIN MAIN THREATS.
OUTLOOK...SUNDAY INTO WEDNESDAY...
SUNDAY AND MONDAY...MODERATE TO HIGH CONFIDENCE. VFR CONDITIONS
DOMINATE.
TUESDAY AND WEDNESDAY...MODERATE CONFIDENCE. VFR CONDITIONS WILL BE
MIXED WITH PERIODS OF MVFR-IFR CIGS/VSBYS IN SCT SHOWERS AND
THUNDERSTORMS AT TIMES. SOME LOW CLOUDS AND FOG PATCHES MAY RESULT
IN LOWER CONDITIONS AT TIMES AS WELL.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
HIGH CONFIDENCE THROUGH SATURDAY NIGHT.
TONIGHT..
WE EXTENDED THE SCA FOR BUZZARDS BAY AND MVY/ACK SOUNDS THROUGH
07Z. WINDS STILL GUSTING TO 25+ KTS AND LLJ REMAINS ACROSS THE
REGION NEXT FEW HOURS BEFORE WEAKENING. OTHERWISE SCA SEAS WILL
PERSIST OVER THE OUTER WATERS. ANOTHER ROUND OF PATCHY FOG
EXPECTED LATER TONIGHT INTO SAT AM.
SAT...
WSW WINDS 15-20 KT WITH GUST UP TO 25 KT POSSIBLE. SCT
AFTN/EVENING TSTM POSSIBLE. A FEW STRONG STORMS POSSIBLE.
SAT NIGHT...
WIND SHIFT FROM SW TO NNW...HOWEVER THIS WILL BE DELAYED ACROSS
THE SOUTHERN WATERS. TSTMS POSSIBLE SOUTH WATERS AS FRONTAL
DEPARTS SLOWLY. LEFTOVER SW WIND WAVES.
OUTLOOK...SUNDAY INTO WEDNESDAY...
SUNDAY AND MONDAY...MODERATE TO HIGH CONFIDENCE. SOME LEFT OVER
MARGINAL SCA SEAS OF 5 FEET WILL BE POSSIBLE MON INTO MON EVENING
ACROSS THE SOUTHERN ATLANTIC WATERS. OTHERWISE...HIGH PRESSURE
BUILDING IN FROM THE NORTH WILL KEEP WINDS/SEAS BELOW SCA THRESHOLDS.
TUESDAY AND WEDNESDAY...MODERATE CONFIDENCE. SCA SEAS MAY DEVELOP
ACROSS OUR SOUTHERN AND SOUTHEAST ATLANTIC WATERS AS LONG SOUTHWEST
FETCH DEVELOPS LATE TUE INTO WED AHEAD OF AN APPROACHING COLD
FRONT.
&&
.CLIMATE...
HERE ARE THE RECORD MIN MAX TEMPS FOR TONIGHT/7.19 (BEFORE
MIDNIGHT)
BOS...78/1991
PVD...76/1952
BDL...75/1982
ORH...73/2005
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...AIR QUALITY ALERT UNTIL 11 PM EDT THIS EVENING FOR CTZ002>004.
HEAT ADVISORY FROM NOON TO 7 PM EDT SATURDAY FOR CTZ002>004.
MA...AIR QUALITY ALERT UNTIL 11 PM EDT THIS EVENING FOR MAZ005-
012>014-026.
HEAT ADVISORY FROM NOON TO 7 PM EDT SATURDAY FOR MAZ005>007-
011>019.
NH...HEAT ADVISORY FROM NOON TO 7 PM EDT SATURDAY FOR NHZ012.
RI...AIR QUALITY ALERT UNTIL 11 PM EDT THIS EVENING FOR RIZ001>008.
HEAT ADVISORY FROM NOON TO 7 PM EDT SATURDAY FOR RIZ001>004.
MARINE...SMALL CRAFT ADVISORY UNTIL 3 AM EDT SATURDAY FOR ANZ232>234.
SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR ANZ230-
231-236-251.
SMALL CRAFT ADVISORY UNTIL 6 AM EDT SATURDAY FOR ANZ235-237-
250-254>256.
&&
$$
SYNOPSIS...FRANK/NOCERA
NEAR TERM...KJC/FRANK
SHORT TERM...NOCERA
LONG TERM...FRANK
AVIATION...FRANK/NOCERA
MARINE...KJC/FRANK/NOCERA
CLIMATE...
AREA FORECAST DISCUSSION
NWS TAUNTON MA
721 AM EDT THU JUL 18 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE MIDWEST AND ATLANTIC COAST WILL BRING
CONTINUED HOT AND HUMID WEATHER TO SOUTHERN NEW ENGLAND THROUGH
SATURDAY. ISOLATED TO WIDELY SCATTERED SHOWERS AND THUNDERSTORMS
ARE POSSIBLE TODAY AND FRIDAY. ON SATURDAY AS A STRONG COLD FRONT
APPROACHES FROM THE GREAT LAKES...THERE IS THE GREATER THREAT FOR
STORMS. RELIEF FROM THE HEAT AND HUMIDITY WILL ARRIVE ON SUNDAY
AND LAST THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
730 AM UPDATE...
FEEL THE LATEST RUNS OF THE HRRR AND WRF-ARW ARE PROVIDING SUBTLE
CLUES AS TO THE OUTCOMES LATER TODAY. COUPLING WITH RAP MODEL
OUTPUT...FEEL THE CAP WILL REMAIN STRETCHED ACROSS THE WESTERN AND
SOUTHERN PORTIONS OF THE LOWER NEW ENGLAND STATES INITIALLY...
WEAKENING SLIGHTLY AS A LOW- TO MID-LEVEL WEAK COLD FRONT SWEEPS
THROUGH NORTHERN NEW ENGLAND.
CONSIDERING THIS POINT AND THE ATTENDANT LONGWAVE FLOW PATTERN...
COULD SEE A REPEAT OF LAST NIGHTS THUNDERSTORM OUTCOMES...BUT
SLIGHTLY SOUTH AND WEST. WILL NEED TO WATCH ANY ACTIVITY AND THE
LONGEVITY OF THAT ACTIVITY AS IT PROGRESSES...WHETHER IT TURNS
MORE RIGHT AWAY FROM THE MEAN FLOW AND MORE WITH CORFIDI VECTOR
FLOW TOWARDS THE AXIS OF GREATER THERMAL-MOIST INSTABILITY AXIS.
HAVE UPDATED CHANCE POPS ACCORDINGLY KEEPING THE BULK OF ACTIVITY
NORTH AND EAST OF A LINE FROM ORANGE MASSACHUSETTS TO PROVIDENCE
RHODE ISLAND WHERE BETTER SHEAR RESIDES. ECHO PREVIOUS FORECASTERS
REMARKS BELOW THAT ANY ADDITIONAL ACTIVITY WILL BE ISOLATED TO
WIDELY SCATTERED. MAIN THREAT CONTINUES TO BE HEAVY RAIN...BUT CAN
NOT RULE OUT A POTENTIAL DAMAGING WIND THREAT WITH STORMS.
PREVIOUS DISCUSSION...
WITH THIS WARM START AND AT LEAST SOME SUNSHINE INITIALLY...TEMPS
ARE LIKELY TO BE A COUPLE OF DEGREES WARMER STILL ACROSS THE
REGION. A WEAK WESTERLY COMPONENT TO THE WIND COULD SUPPLY ENOUGH
DOWNSLOPE FOR THE LOWER CT VALLEY TO REACH THE UPPER 90S TO
POSSIBLY EVEN NEAR THE CENTURY MARK. EXPECTING MIXED DWPTS TO
REMAIN IN THE UPPER 60S TO LOW 70S. GIVEN ALL OF THIS...STILL
SEEING 105+ HEAT INDICES ALONG THE NRN CT/RI AND SRN MA...SO NO
CHANGES TO THE CURRENT HEAT HEADLINES. A VERY HOT AND VERY HUMID
DAY IS EXPECTED IN SPITE OF THE REMNANT CLOUD COVER. SEA BREEZES
MAY MOVE IN LATE AS UPPER LVL FLOW WEAKENS SOMEWHAT...SO WARMER
NEAR THE CLOSE UNTIL THE RELIEF ARRIVES.
THE OTHER ISSUE TODAY IS THE POTENTIAL FOR CONVECTION. WITH WARMER
LOW LVL TEMPS AND AND A COLD FRONT JUST UPSTREAM...AM NOTING A BIT
COOLER MID LVL TEMPS AND SLIGHTLY LESS OF A CAP TODAY THAN
PREVIOUS DAYS. ALSO...WITH THE RIDGE BEGINNING TO BREAK DOWN AND
SLIDE E...LOWERING HEIGHTS MAY COMBINE WITH A WEAK REMNANT PRE
FRONTAL TROF AS A TRIGGER FOR DIURNAL CONVECTION. ML CAPE VALUES
SHOULD APPROACH THE 1500-2000J/KG MARK. VERY LITTLE SHEAR SUGGESTS
THAT ANY STORMS THAT FORM WOULD HAVE DIFFICULTY ORGANIZING LEADING
TO THE BIGGEST THREAT BEING HEAVY RAIN...ALTHOUGH THE LATEST
SWODY1 PROBABILISTIC VALUES HAVE MUCH OF THE BOX CWA IN THE 5
PERCENT WIND/HAIL THREATS GIVEN THE AMOUNT OF AVAILABLE CAPE. FEEL
THAT ANY CONVECTION WOULD BE ISOLATED TO WIDELY SCATTERED GIVEN H7
TEMPS ARE STILL NEAR +10C...AND THE BEST FORCING/SHEAR IS
UPSTREAM. IT APPEARS THE HIGHEST LIKELIHOOD FOR A STORM WOULD BE
IF ONE FORMS UPSTREAM THEN RIDES THE HIGHER INSTABILITY GRADIENT
INTO SRN NEW ENGLAND.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
UPPER LVL RIDGE BEINGS MAKING ITS SLIDE TO THE S AND E ALLOWING
RETURN FLOW TO BEGIN TO DOMINATE OVERNIGHT. THIS ALLOWS THE
STALLED FRONT TO THE N TO LIFT AS A WARM FRONT ALLOWING STILL
WARMER AIR INTO THE LOW MID LVLS. THIS PROVIDES YET A BETTER CAP
OVERNIGHT...AND COMBINING THIS WITH THE LOSS OF DIURNAL HEAT...AND
ANY STORMS OR SHOWERS SHOULD DISSIPATE THROUGH ABOUT MIDNIGHT.
WARMER RETURN FLOW AND LEFTOVER CONVECTIVE DEBRIS MAY KEEP MIN
TEMPS WELL INTO THE 70S OVER MUCH OF THE REGION. SOME LATE NIGHT
FOG/STRATUS IS POSSIBLE ALONG THE SOUTH COAST/CAPE/ISLANDS.
FRI...
SW RETURN FLOW THROUGH THE DAY THANKS TO WARM ADVECTION BEHIND A
WARM FRONT LIFTING INTO CANADA. THIS RAISES MID LVL TEMPS FURTHER
STILL WITH THE POSSIBILITY OF H7 TEMPS WARMER THAN +10C BY THE
HEAT OF THE AFTERNOON. COLUMN MOISTURE DOES INCREASE THROUGH THE
DAY THANKS TO THIS FLOW WITH PWAT VALUES AROUND 2.0 INCHES BY THE
LATTER HALF OF THE DAY. THIS ALLOWS CAPE VALUES TO RISE...BUT WITH
A VERY WARM CAPPING INVERSION IN PLACE...IT MAY BE DIFFICULT TO
GET ANY THUNDERSTORMS OR SHOWERS TO FORM WITH LITTLE FORCING
/TOUGHER SETUP FOR SEA BREEZES WITH STRONG RETURN FLOW/. NOT OUT
OF THE QUESTION ANOTHER LEE/WARM AIR TROF FORMS...BUT HAVE LOWER
CONFIDENCE IN STORM DEVELOPMENT UNLESS A STRONGER SOURCE FOR LIFT
IS APPARENT. POPS ARE A BIT LOWER THAN THU BECAUSE OF THIS FACT.
THE THREAT IS NON-ZERO HOWEVER...GIVEN THE HIGH CAPE VALUES AND
STRENGTHENING SW FLOW ALOFT.
ANOTHER ROUND OF HOT AND HUMID CONDITIONS FRI IN SPITE OF THE
POSSIBILITY OF EARLY DAY SCT-BKN CLOUD COVER. WARMING MID LVL
TEMPS MAY BE ENOUGH TO OVERCOME ANY CLOUD COVER AS MIXING STILL
REACHES NEAR H8. THEREFORE...ANOTHER ROUND OF TEMPS IN THE LOW-
UPPER 90S POSSIBLE WITH DWPTS HOLDING IN THE LOW TO MID 70S.
ANOTHER ROUND OF HEAT ADVISORIES AND EXCESSIVE HEAT WARNINGS ARE
POSSIBLE...POSSIBLY EXPANDING TO THE I-495 CORRIDOR AND E AS THE W
COMPONENT TO THE FLOW SHOULD FORCE SEA BREEZES TO REMAIN OFFSHORE.
WILL NEED TO MONITOR FOR FURTHER HEAT HEADLINES.
WINDS PICK UP DURING THE AFTERNOON POSSIBLY REACHING 20-30 MPH IN
SPOTS BY LATE IN THE DAY. THIS MAY HELP THE S COAST GIVEN THE SW
DIRECTION...BUT GIVEN THE WARM ADVECTION ASSOCIATED WITH THIS
FLOW...IT WILL LIKELY PROVIDE LITTLE RELIEF FURTHER INLAND.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
HEADLINES...
* SEVERE WEATHER ANTICIPATED FOR SATURDAY INTO SATURDAY NIGHT
* SHOWERS LINGERING SUNDAY...OTHERWISE TURNING COOL/DRY INTO TUESDAY
* WARMER WITH THUNDERSTORMS WEDNESDAY INTO THE END OF THE WEEK
*/OVERVIEW AND MODEL CONSENSUS...
WILL FOLLOW WITH A NON-NAM COMPROMISE BETWEEN THE GFS AND ECMWF AS
IT IS EASILY DISCERNIBLE AND HPC/WPC HAS EMPHASIZED THAT THE NAM
IS AN OUTLIER AND LAGS OTHER MODELS/ENSEMBLE MEANS CONCERNING THE
COLD FRONT FOR SATURDAY. WILL CONTINUE WITH CONTINUITY CONSIDERING
A BLEND OF ENSEMBLE MEANS WITH DETERMINISTIC FORECAST OUTCOMES
FROM THE GFS/ECMWF THROUGH TUESDAY...FOLLOWING THE ECMWF
THEREAFTER FEELING THERE ARE CONVECTIVE FAILURES WITH THE 18.0Z
GFS.
*/DAY-TO-DAY DETAILS...
*/SATURDAY...
HIGH PRESSURE SHIFTING TOWARDS THE FOUR-CORNERS AS AN AREA OF LOW
PRESSURE AMPLIFIES ACROSS NORTHERN ONTARIO ALLOWS FOR HEIGHT FALLS
OVER THE NORTHEASTERN CONUS. AN ATTENDANT COLD FRONT TO THE LOW IS
THE FOCUS OF LOW- TO MID-LEVEL FRONTOGENESIS COUPLED WITH THE MAIN
MID- TO UPPER-LEVEL IMPULSE AND RIGHT-REAR QUADRANT OF THE UPPER-
LEVEL JET WILL GENERATE AN ENVIRONMENT OF FAVORABLE DEEP-LAYER
ASCENT. CONSIDERING A DESTABILIZING VERY WARM AND MOIST AIRMASS
ALONG AND AHEAD OF THE COLD FRONT...THERE IS THE EXPECTATION FOR A
SUSTAINING LINE OF STRONG TO SEVERE THUNDERSTORMS /ECHOED BY THE SPC
DAY 3 OUTLOOK/.
UNI-DIRECTIONAL WEST-SOUTHWEST SHEAR SUPPORTS AN ENVIRONMENT OF
CONVECTIVE LINE SEGMENTS AND MULTI-CELLULAR THUNDERSTORM CLUSTERS
PRESENTING THE THREAT OF STRONG TO DAMAGING WINDS. IN ADDITION...
WITH THE DEEP-MOIST RICH ATMOSPHERE /PWATS UP TO 2 INCHES/ HEAVY
RAIN IS ANTICIPATED ALONG WITH LOCALIZED FLASH FLOODING. NOT SO
CERTAIN ON THE NEED OF FLOOD WATCH HEADLINES AS BOTH FLOW AND COLD
FRONTAL PASSAGED ARE PROGRESSIVELY MODELED.
CONCERNING INSTABILITY...MID-LEVEL LAPSE RATES ARE MARGINAL. THERE
IS SOME QUESTION AS TO WHETHER THE BOUNDARY LAYER WILL EFFECTIVELY
DESTABILIZE. THERE ARE SUBTLE HINTS OF LIMITATIONS DUE TO CLOUD
DEBRIS...INITIAL ACTIVITY ALONG A PRE-FRONTAL TROUGH...AND/OR A
CAPPING INVERSION AT H85 NEAR +20C. FEEL CONFIDENT THAT THE REGION
WILL REMAIN CAPPED INTO THE AFTERNOON ALLOWING THE WARM-SECTOR TO
DEVELOP AND DESTABILIZE. SHOWERS AND THUNDERSTORMS ALONG WITH
ATTENDANT THREATS WILL INCREASE IN COVERAGE AND REMAIN FOCUSED ALONG
THE COLD FRONT WITH DEEP-LAYER LIFT. HIGH FREEZING LEVELS AND THIN
CAPES SUPPORT THE THREAT FOR SMALL HAIL BELOW SEVERE THUNDERSTORM
THRESHOLDS OF 1 INCH.
GREATEST CONFIDENCE OF AFOREMENTIONED THREATS ACROSS INTERIOR NEW
ENGLAND /ESPECIALLY TO THE WESTERN HALF OF NEW ENGLAND/...WEAKENING
SOUTH AND EAST DURING THE NOCTURNAL PASSAGE GRADUALLY OFFSHORE.
HIGHS INTO THE LOW-90S WITH LOW-70 DEWPOINTS. SOUTHWEST WINDS AHEAD
OF THE FRONT GUSTING AROUND 25 MPH...BACKING OUT OF THE NORTH-
NORTHWEST AND WEAKENING WITH COLD FRONTAL PASSAGE. GFS AND ECMWF
DETERMINISTIC AND ENSEMBLE GUIDANCE SUCCINCT ON THE SURFACE COLD
FRONT OFFSHORE OF NEW ENGLAND BY SUNDAY MORNING.
*/SUNDAY INTO TUESDAY...
COLD FRONT CONTINUES TO DRIFT OUT TO SEA. WILL NEED TO MONITOR WEAK
WAVE DISTURBANCES INVOKING AREAS OF LOW PRESSURE ALONG THE FRONTAL
BOUNDARY WHICH COULD POTENTIALLY SWING WET WEATHER BACK WEST. WILL
KEEP CHANCE TO SLIGHT CHANCE POPS FOR SOUTH-SOUTHEAST NEW ENGLAND ON
SUNDAY.
OTHERWISE...CANADIAN HIGH PRESSURE WILL BUILD ACROSS THE REGION
USHERING COOLER AND SEASONABLE CONDITIONS FOR SOUTHERN NEW ENGLAND
PUTTING AN END TO THE OPPRESSIVE HEAT AND HUMIDITY. WILL KEEP DRY
CONDITIONS THROUGH TUESDAY FEELING THAT RIDGING OF HIGH PRESSURE AS
IT MOVES EAST TOWARDS NEWFOUNDLAND WILL KEEP ANY THUNDERSTORM
ACTIVITY WITH RETURN SOUTHERLY FLOW WEST OF THE FORECAST REGION
ACROSS NEW YORK AND PENNSYLVANIA.
*/WEDNESDAY INTO THE WEEK...
WITH GREATER WEIGHT TOWARDS THE ECMWF...RETURN SOUTHERLY FLOW
COUPLED WITH BROAD TROUGHING BUILDING ACROSS THE REGION WITH
TRAVERSING WEAK WAVE DISTURBANCES SHOULD INVOKE A WEAK AREA OF LOW
PRESSURE ACROSS THE NORTHEASTERN CONUS WITH SUBSEQUENT PERIODS OF
SHOWERS AND THUNDERSTORMS...LIKELY DURING THE DAY WITH BOUNDARY
LAYER DESTABILIZATION.
WILL KEEP CONDITIONS CLOSE TO SEASONABLE LEVELS WITH PREVAILING
SOUTHERLY FLOW AS THE LOW- TO MID-LEVEL LOW PRESSURE TRACKS
NORTHEASTWARD TO THE WEST OF SOUTHERN NEW ENGLAND. CONTINUED LOW
CONFIDENCE OF SEVERE WEATHER THREATS...HEAVY RAIN CERTAINLY PLAUSIBLE.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
MODERATE CONFIDENCE THROUGH FRIDAY...
VFR. HAVE GROWING CONFIDENCE OF SHRA/TSRA NORTH AND EAST OF A LINE
FROM ORE-PVD. VCTS PREVAILED ACCORDINGLY FOR THE LATE AFTERNOON
INTO EARLY EVENING PERIOD. ACTIVITY ELSEWHERE WILL BE ISOLATED TO
WIDELY SCATTERED. LOW-VFR/MVFR CIGS WITH TSRA...WHILE ANY +RA
WILL LIKELY BE ASSOCIATED WITH MVFR/IFR VSBYS. OTHERWISE...SEA-
BREEZES ALONG THE EAST AND SOUTH SHORES AROUND MIDDAY.
PATCHY FOG LATER TONIGHT AND AGAIN FRIDAY NIGHT ESPECIALLY ALONG
THE SOUTH COAST AND ISLANDS WITH AREAS OF IFR-VLIFR CIGS/VSBYS
POSSIBLE.
KBOS TERMINAL...MODERATE CONFIDENCE IN TAF TRENDS. SEA-BREEZE
AROUND MIDDAY. VCTS POSSIBLE IN THE LATE AFTERNOON INTO EARLY
EVENING HOURS.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF. DID NOT PREVAIL VCTS DUE
TO LESSER CONFIDENCE.
OUTLOOK...SATURDAY INTO TUESDAY...
SATURDAY...MODERATE CONFIDENCE.
SHRA/TSRA AHEAD OF A COLD FRONT SWEEPING THROUGH THE TERMINALS LATE
IN THE DAY...OFFSHORE BY SUNDAY MORNING. TSRA MAY BE STRONG TO
SEVERE WITH GUSTY WINDS AND SMALL HAIL...AWW/S POSSIBLE WITH THE
ADDITIONAL THREAT OF LIGHTNING. LOW-VFR/MVFR CIGS WITH TSRA...
MVFR/IFR VSBYS WITH +RA. SOUTHWEST WINDS GUSTING AROUND 25 MPH
BACKING OUT OF THE NORTH-NORTHWEST AND WEAKENING WITH COLD FRONTAL
PASSAGE.
SUNDAY INTO TUESDAY...MODERATE CONFIDENCE.
VFR. LIGHT AND VARIABLE FLOW. SEA-BREEZES POSSIBLE DURING THE MIDDAY
INTO AFTERNOON HOURS SUNDAY AND MONDAY. MAY SEE A RETURN OF
SHRA/TSRA FOR TUESDAY.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
HIGH CONFIDENCE THROUGH TONIGHT...MODERATE CONFIDENCE ON FRIDAY
REGARDING THREAT FOR SMALL CRAFT ADVISORY CONDITIONS...
WINDS AND SEAS REMAIN BELOW SMALL CRAFT ADVISORY LEVEL THRESHOLDS
THROUGH THE OVERNIGHT HOURS TONIGHT ALTHOUGH WINDS WILL GRADUALLY
SHIFT FROM W TO SW DURING THE OVERNIGHT HOURS. SOME MARINE
FOG/STRATUS IS POSSIBLE LATE TONIGHT/EARLY FRI MORNING
PARTICULARLY ON SRN WATERS.
INCREASING SW FLOW MAY ALLOW WINDS TO REACH NEAR 25 KT
PARTICULARLY ALONG THE NEAR SHORE WATERS NEAR THE SOUTH COAST
CAPE/ISLANDS. THE INCREASING FLOW MAY ALSO ALLOW SEAS TO REACH 5+
FT BY THE LATE DAY EARLY FRI NIGHT TIMEFRAME ON PARTICULARLY ON
THE SRN AND SERN OCEAN WATERS. SMALL CRAFT ADVISORIES MAY BE
NECESSARY.
OUTLOOK...SATURDAY INTO TUESDAY...
SATURDAY INTO SUNDAY...MODERATE CONFIDENCE.
SHOWERS AND THUNDERSTORMS AHEAD OF A COLD FRONT SWEEPING INTO THE
WATERS AROUND MIDNIGHT SUNDAY...EXITING WELL OUT TO SEA LATE SUNDAY.
THUNDERSTORMS MAY BE STRONG TO SEVERE WITH FREQUENT LIGHTNING...GALE
FORCE WINDS...AND HEAVY RAIN /RESULTING IN VISIBILITY RESTRICTIONS/.
WILL SEE SOUTHWEST GUSTS AROUND 25 KTS PRIOR TO FRONTAL PASSAGE
/SEAS BUILDING TO AROUND 6 FEET OVER THE SOUTH-SOUTHEAST WATERS/...
BACKING OUT OF THE NORTH-NORTHEAST AND WEAKENING /ALLOWING SEAS TO
RELAX/. SMALL CRAFT ADVISORIES LIKELY.
MONDAY INTO TUESDAY...MODERATE CONFIDENCE.
HIGH PRESSURE IN CONTROL ALLOWING FOR LIGHT AND VARIABLE FLOW. WINDS
WILL BEGIN TO TURN MORE SOUTHERLY INTO TUESDAY AS THE HIGH SHIFTS
EAST. LOW CONFIDENCE CONCERNING SHOWERS AND THUNDERSTORMS ALONG THE
NEAR-SHORE WATERS FOR LATE TUESDAY.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...EXCESSIVE HEAT WARNING FROM 11 AM THIS MORNING TO 7 PM EDT
THIS EVENING FOR CTZ002>004.
MA...AIR QUALITY ALERT FROM 11 AM THIS MORNING TO 11 PM EDT THIS
EVENING FOR MAZ020>024.
HEAT ADVISORY FROM 11 AM THIS MORNING TO 7 PM EDT THIS EVENING
FOR MAZ003>007-010>012-014>016-019-026.
EXCESSIVE HEAT WARNING FROM 11 AM THIS MORNING TO 7 PM EDT
THIS EVENING FOR MAZ013-017-018-020-021.
NH...HEAT ADVISORY FROM 11 AM THIS MORNING TO 7 PM EDT THIS EVENING
FOR NHZ012.
RI...AIR QUALITY ALERT FROM 11 AM THIS MORNING TO 11 PM EDT THIS
EVENING FOR RIZ003>008.
HEAT ADVISORY FROM 11 AM THIS MORNING TO 7 PM EDT THIS EVENING
FOR RIZ005-007.
EXCESSIVE HEAT WARNING FROM 11 AM THIS MORNING TO 7 PM EDT
THIS EVENING FOR RIZ001>004-006.
MARINE...NONE.
&&
$$
SYNOPSIS...DOODY/SIPPRELL
NEAR TERM...DOODY/SIPPRELL
SHORT TERM...DOODY
LONG TERM...SIPPRELL
AVIATION...DOODY/SIPPRELL
MARINE...DOODY/SIPPRELL
AREA FORECAST DISCUSSION
NWS ALBANY NY
135 AM EDT THU JUL 18 2013
.SYNOPSIS...
HIGH PRESSURE AT ALL LEVELS OF THE ATMOSPHERE...WILL RECEDE FROM
THE MIDWEST TO THE ATLANTIC SEABOARD BY FRIDAY. A WEAK BOUNDARY WILL
DRIFT INTO AND OUT THE SAINT LAWRENCE TONIGHT AND
THURSDAY...TRIGGERING SCATTERED THUNDERSTORMS. OTHERWISE THE HEAT
AND HUMIDITY WILL PERSIST INTO UGH SATURDAY. A STRONG COLD FRONT
WILL PUSH THROUGH THE REGION SATURDAY...TRIGGERING THUNDERSTORMS AND
USHERING IN MORE A MORE SEASONABLE AIR MASS INTO OUR REGION TO START
THE NEW WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 1230 AM EDT...RADARS STILL INDICATING WIDELY SCATTERED SHOWER
ACTIVITY ACROSS THE ADIRONDACKS...EASTWARD INTO SOUTHERN VERMONT.
THESE APPEARED TO BE TIED INTO A WEAK BOUNDARY JUST TO NORTH OF THIS
REGION. INTERESTING THE EXPERIMENTAL HRRR HAS INDICATED A BROKEN
LINE OF SHOWERS AND POSSIBLY THUNDERSTORMS WORKING SOUTH THROUGH THE
CAPITAL REGION AND EVEN POINTS SOUTH OVERNIGHT.
WHILE THIS SCENARIO CANNOT BE RULED OUT...WE LEAN AGAINST IT SINCE
OUR RAOB INDICATED OUR MID LEVELS REMAINED CAPPED (VERY WARM
TEMPERATURES AROUND +10C AROUND 10,000 FEET) WHICH HAS BEEN ABLE TO
SUPPRESS CONVECTION THUS FAR. ALSO...WE HAVE LOST THE HEATING OF THE
DAY AND THE FRONT SHOULD STAY NORTH. THERE WAS ONE INTERESTING
FEATURE ON THE H20 VAPOR LOOP...A DISTINCT DRY PUNCH WELL TO OUR
NORTH WHICH COULD ALSO BE CONTRIBUTING TO THE SHOWER ACTIVITY. THIS
FEATURE SHOULD ALSO STAY TO THE NORTH.
WE DID EXTENT ISOLATED COVERAGE OF SHOWERS (AND SLIGHT CHANCE OF
THUNDERSTORMS) SOUTH TO ABOUT SARATOGA SPRINGS FOR A COUPLE OF
HOURS...WHILE KEEPING AREAS FROM THE CAPITAL DISTRICT SOUTHWARD DRY
(POPS LESS THAN 15 PERCENT).
THIS LEAVES US WITH AN OPPRESSIVE NIGHT. TEMPERATURES WERE STILL
OVER 80S IN THE CAPITAL DISTRICT...AND CLOSE TO 80 ACROSS MOST OTHER
AREAS. DEWPOINTS WERE AROUND 70. AND NOW WE ALSO HAVE SOME HAZE TON
CONTEND WITH.
THERE WAS STILL A LITTLE BREEZE OUT OF THE WEST WHICH COULD KEEP UP
IN SOME AREAS ALL NIGHT LONG.
FOR ALL THE ABOVE REASONS...RAISED TEMPERATURES A COUPLE DEGREES
ACROSS MANY AREAS. THIS WOULD MEAN OVERNIGHT LOWS WOULD ONLY FALL
TO ABOUT THE MID 70S FROM ALBANY SOUTHWARD...CLOSER TO 70 IN
OUTLYING AREAS. THESE VALUES WILL AVERAGE MORE THAN 10 DEGREES ABOVE
NORMAL FOR THE TIME OF YEAR.
THURSDAY...THE CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE ON THE
INCREASE DURING THE AFTERNOON. THE UPPER LEVEL HIGH PRESSURE WILL BE
SUPPRESSED TO THE SOUTH. THIS WILL CHANGE OUR FLOW TO ZONAL FLOW.
THIS COULD ALLOW FOR A DISTURBANCE OR TWO EMBEDDED IN THE INCREASING
FLOW TO MOVE THROUGH AND PRODUCE SCATTERED CONVECTION MAINLY DURING
THE AFTERNOON AND EVENING. MODELS ARE SHOWING DECENT CAPE ACROSS THE
REGION FROM 1000 J/KG TO 2500 J/KG.
TEMPERATURES ON THURSDAY WILL ONLY AGAIN BE HOT WITH TEMPERATURES
ABOVE 90 ACROSS THE GREATER CAPITAL REGION SOUTHWARD. WILL LIKELY
HOIST HEAT ADVISORIES...ESPECIALLY ACROSS THE SOUTH.
THURSDAY NIGHT...ANY SHOWERS AND THUNDERSTORMS SHOULD DIMINISH WITH
THE LOSS OF HEATING. LOWS THURSDAY NIGHT WILL BE IN THE UPPER 60S
TO LOWER 70S.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ONE MORE HOT DAY...THEN THE HEAT BREAKS...
BY FRIDAY THE 500HPA RIDGE CENTER IS ALONG THE MID ATLC COAST
WITH A ZONAL W FLOW ACROSS THE N TIER OF THE USA. EMBEDDED IN THIS
FLOW IS A SHORT WV FM LK HURON TWRD CHI FRI MORNING. AT SFC A
CDFNT IS MOVING INTO UPR GRTLKS AS THE BERMUDA HIGH HAS MOVED
OFFSHORE. DURING THE DAY FRIDAY THE APPROACHING SHORT WV BUILDS
THE RIDGE SLIGHTLY INTO THE RGN AND INCR WSW FLOW. WSW FLOW WILL
RESULT IN ADDITIONAL DIABATIC WARMING EAST OF APPALACHIANS. WITH
PS TO MS SKIES...TEMPS MAY REACH MAX VALUES FOR THIS STRETCH...WITH
90S COMMON AND MID TO UPPER 90S IN VALLEYS. ONLY FACTOR THAT COULD
CUT THEM BACK IS AMOUNT OF CONVECTIVELY INDUCED CLOUD COVER. TD
WILL REMAIN IN THE 70S AND HEAT ADVISORIES OR POSSIBLE WARNINGS
MAY BE NEEDED AGAIN FOR FRI.
NAM MODEL SOUNDINGS REASSERT A CAP ACROSS RGN FRI AT 650 HPA WITH
2600 J/KG OF CAPE IS TRAPPED UNDER IT. GFS HAS SIMILAR CAP AT
740HPA...AND CAPES FM 1000-2200 J/KG. BOTH MODELS 500HPA TEMPS INCR
BACK TO -6C TO -7C FRI.
250HPA JET REMAINS WELL NORTH OF RGN MUCH OF FRI. GFS BRINGS FCA
UNDER THE INFLUENCE OF THE RIGHT ENTRANCE RGN FRI NT...WITH AREAS OF
DIVERGENCE (FORCING) MOVING INTO N TIER LATE FRI. THE NAM IS
SLOWER IN THIS TIMING. BOTH MODELS BRING 40-50KT 850HPA WSW JET INTO
THE ST LAWRENCE VLY BY FRI EVNG.
POPS IN MOST GUIDANCE SUITE ALONG LINES OF 25-35PCT FRI. WHILE CAPES
ARE LARGE...THEY WILL BE LARGELY CAPPED TILL LATE INTO THE AFTN OR
EARLY EVENING. THEN SCT TSTMS DIURNALLY AND ELEVATED TRRN DRIVEN
WILL POKE THROUGH THE CAP. TSTMS WILL BE SUSTAINED OVERNIGHT BY
BOUNDARY INTERACTIONS...INCRG DYNAMIC FORCING AND THE APPROACHING
CDFNT. SPC HAS DAY 3 SLIGHT RISK JUST TOUCHING NW PORTIONS OF
FCA...WITH THESE INCR DYNAMICS FRI NT AND WINDS THE PRIMARY CONCERN.
FRIDAY NIGHT WILL BE ANOTHER SULTRY NIGHT WITH TD AROUND 70 AND LOWS
FALLING ONLY TO THE 70S.
SATURDAY WILL BRING AN END TO THE OPPRESSIVE HEAT IN THE FCA. CDFNT
WILL MOVE INTO THE ST LAWRENCE VLY...THEN SE ACROSS THE FCA SAT. A
PREFRONTAL TROF AHEAD OF THIS CDFNT WILL INITIATE CONVECTION.
THE NAM/GEM BRINGS THESE FEATURES THROUGH DURING THE MORNING...WHILE
THE GFS DOES SO DURING PEAK HEATING OF THE DAY IN THE AFTN.
SPC HAS FCA IN DAY 4 OUTLOOK SVR...HWVR TIMING OF CDFNT WILL DICTATE
LOCATION AND MAGNITUDE OF TSTM RESPONSE. 850 JET OF 25-40 KTS AND
RIGHT ENTIRE REGION OF 250 JET LINE UP0 ACROSS RGN AS CDFNT SHIFTS
S.
ATTM THE THREAT IS GREATEST ACROSS THE S HALF FCA...AS MOST GUIDANCE
BRINGS IT THROUGH THE N AREAS BEFORE BETTER DYNAMICS ALIGN WITH THE
CDFNT AND MAX HEATING. THIS WILL BE REFINED WITH ECMWF IN GRIDS.
IN THE COLD FRONTS WAKE...MORE SEASONABLE AND COMFORTABLE AIR WILL
STREAM INTO FCA LATE SAT AND SAT NT. TD WILL FALL INTO THE 60S...AS
SKIES CLEAR.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
THE LONG TERM PERIOD WILL BE CHARACTERIZED BY A RETURN TO MORE
SEASONABLE TEMPERATURES AND INCREASING CHANCES FOR MAINLY
AFTERNOON/EARLY EVENING SHOWERS AND THUNDERSTORMS FOR NEXT WEEK.
AT THE START OF THE LONG TERM PERIOD...LONG RANGE GUIDANCE FROM THE
12Z GFS/ECMWF/GGEM ARE IN GOOD AGREEMENT WITH THE PASSAGE OF THE
COLD FRONT THROUGH THE FORECAST AREA BY SUNDAY MORNING. THIS COLD
FRONTAL PASSAGE WILL MARK AN END TO THE HEAT WAVE ACROSS THE
FORECAST AREA...WHILE ALSO USHERING IN REFRESHINGLY LOWER HUMIDITY
LEVELS AS DEWPOINTS DROP INTO THE MID TO UPPER 50S. A BROAD AREA OF
CANADIAN HIGH PRESSURE WILL GRADUALLY BUILD IN AT THE SURFACE AND
PERSIST THROUGH THE REMAINDER OF THE WEEKEND AND INTO THE BEGINNING
OF NEXT WEEK.
THE CANADIAN HIGH PRESSURE WILL SLOWLY DRIFT SOUTHWARD BY
MONDAY...ALLOWING FOR SOME WEAK SOUTHERLY/SOUTHWESTERLY RETURN FLOW
AROUND THE HIGH. THIS RETURN FLOW WILL ALLOW DEWPOINTS TO CREEP UP
SLIGHTLY TOWARDS 60 IN SOUTHERN AREAS AND GIVEN NORTHWEST FLOW
ALOFT...CANNOT RULE OUT AN ISOLATED TERRAIN-INFLUENCED
SHOWER/THUNDERSTORM OR TWO POPPING UP DURING THE AFTERNOON HOURS.
THE LONG TERM FORECAST BECOMES A LITTLE MORE UNCERTAIN BEGINNING
TUESDAY AS THE CANADIAN HIGH PRESSURE LOOSENS ITS GRIP ACROSS THE
FORECAST AREA. ALOFT...RIPPLES OF ENERGY WILL BE MOVING THROUGH THE
NORTHWEST FLOW HELPING TO TRIGGER MAINLY AFTERNOON/EARLY EVENING
SHOWERS AND THUNDERSTORMS ACROSS THE FORECAST AREA. WILL ONLY
MENTION SLIGHT CHANCE POPS AT THIS TIME AS FORCING DOES NOT APPEAR
TO BE OVERLY STRONG DURING THIS TIME PERIOD. HOWEVER...BOTH THE 12Z
ECMWF/GFS HINT AT A STRONGER SHORTWAVE MOVING THROUGH THE FLOW
THURSDAY WHICH COULD BRING AN INCREASED THREAT FOR CONVECTION BUT
THE EXACT DETAILS ARE STILL TOO EARLY TO DETERMINE AT THIS TIME.
TEMPERATURES WILL RETURN TO MORE SEASONABLE LEVELS ALONG WITH A
NOTICEABLE DECREASE IN HUMIDITY DURING THE LONG TERM PERIOD. HIGHS
WILL GENERALLY BE FROM AROUND 70 IN NORTHWEST ZONES TO THE LOWER 80S
IN SOUTHERN ZONES. LOWS WILL GENERALLY BE IN THE LOWER 50S TO LOWER
60S. TEMPERATURES AND HUMIDITY WILL SLOWLY INCREASE NEXT WEEK
WARMING INTO THE MID 80S BY THE END OF THE PERIOD WITH A RETURN TO
LOWER 60S DEWPOINTS.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
SOME CONVECTION HAS REDEVELOPED ACROSS KGFL AND KPOU WITH SEVERAL
LIGHTNING STRIKES NEAR KPOU. WE WILL HANDLE THIS WITH TEMPO GROUPS
AND/OR VICINITY AS WE MONITOR TRENDS. REMAINDER OF THE OVERNIGHT
WE WILL LIKELY SEE PATCHY FOG AND/OR HAZE FORMATION AS DEWPOINTS
REMAIN IN THE 70S FOR THE MOST PART. MAINLY SCT CIGS WITH SOME BKN
LEVELS FROM TIME TO TIMES SEEN IN THE IR SATELLITE ENHANCEMENTS.
AFTER SUNRISE...VFR CONDITIONS EXPECTED FOR THE DAY AS WE MONITOR
THE POTENTIAL FOR ADDITIONAL AFTERNOON CONVECTION. AT THIS
TIME...WE WILL PLACE A VCSH AT TAF LOCATIONS THIS AFTERNOON.
WESTERLY WINDS GENERALLY 10KTS OR LESS ARE EXPECTED.
WE ARE STARTING A NEW EXPERIMENTAL FORMAT FOR DISPLAYING THE
EXTENDED PORTION OF THE AVIATION DISCUSSION. THIS FORMAT BREAKS THE
EXTENDED PERIODS INTO 12-HOUR INCREMENTS. IT DOES NOT INCLUDE THE
POSSIBILITY OF IFR/VFR BUT THE POTENTIAL SENSIBLE WEATHER AND
"POTENTIAL" IMPACT THE WEATHER MIGHT CAUSE. WE HAVE OMITTED THE WORD
POTENTIAL TO KEEP THE VERBIAGE SHORTER.
WEDNESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIGNIFICANT WEATHER.
THURSDAY: MODERATE OPERATIONAL IMPACT. SLIGHT CHANCE OF RAIN AND
THUNDER STORMS.
THURSDAY NIGHT: MODERATE OPERATIONAL IMPACT. SLIGHT CHANCE OF
RAIN SHOWERS...THUNDER STORMS.
FRIDAY: MODERATE OPERATIONAL IMPACT. BREEZY SLIGHT CHANCE OF RAIN
SHOWERS...THUNDER STORMS.
FRIDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF RAIN
SHOWERS...THUNDER STORMS.
SATURDAY: HIGH OPERATIONAL IMPACT. LIKELY RAIN SHOWERS...THUNDER
STORMS.
SATURDAY NIGHT: NO OPERATIONAL IMPACT. NO SIGNIFICANT
WEATHER. SUNDAY: NO OPERATIONAL IMPACT. NO SIGNIFICANT WEATHER.
SUNDAY NIGHT: NO OPERATIONAL IMPACT. NO SIGNIFICANT WEATHER.
MONDAY: MODERATE OPERATIONAL IMPACT. SLIGHT CHANCE OF RAIN
SHOWERS...THUNDER STORMS.
&&
.FIRE WEATHER...
HIGH PRESSURE AT ALL LEVELS OF THE ATMOSPHERE...WILL RECEDE FROM
THE MIDWEST TO THE ATLANTIC SEABOARD BY FRIDAY. A WEAK BOUNDARY WILL
DRIFT INTO AND OUT THE SAINT LAWRENCE TONIGHT AND
THURSDAY...TRIGGERING SCATTERED THUNDERSTORMS. OTHERWISE THE HEAT
AND HUMIDITY WILL PERSIST INTO UGH SATURDAY. A STRONG COLD FRONT
WILL PUSH THROUGH THE REGION SATURDAY...TRIGGERING THUNDERSTORMS AND
USHERING IN MORE A MORE SEASONABLE AIR MASS INTO OUR REGION TO START
THE NEW WEEK.
RH VALUES WILL REMAIN ELEVATED FOR THE NEXT SEVERAL DAYS. LOOK FOR
FULL RECOVERIES AT NIGHT AND RH VALUES ONLY DROPPING TO 40 TO 60
PERCENT EACH AFTERNOON (HIGHEST ACROSS THE MOUNTAINS).
SCATTERED MAINLY AFTERNOON AND EVENING THUNDERSTORMS ARE POSSIBLE
INTO FRIDAY NIGHT. MORE NUMEROUS SHOWERS AND THUNDERSTORMS ARE
POSSIBLE SATURDAY. HEAVY RAINFALL WILL BE POSSIBLE WITH ANY
THUNDERSTORMS...ESPECIALLY SATURDAY.
&&
.HYDROLOGY...
SCATTERED MAINLY AFTERNOON AND EVENING THUNDERSTORMS ARE POSSIBLE
INTO FRIDAY NIGHT. MORE NUMEROUS SHOWERS AND THUNDERSTORMS ARE
POSSIBLE SATURDAY. HEAVY RAINFALL WILL BE POSSIBLE WITH ANY
THUNDERSTORMS...ESPECIALLY SATURDAY.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.CLIMATE...
TO ACCESS HEAT RELATED CLIMATE DATA INCLUDING HEAT WAVES...NUMBER
90+ DEGREES DAYS AND 100+ DEGREES DAYS...PLEASE VISIT
WWW.WEATHER.GOV/ALY/CLIMATE (ALL LOWER CASE) AND GO TO THE
RECORDS... EXTREMES... PAGE FOR ALBANY.
NUMBER OF 90+ DEGREE DAYS AND RECORD HIGHS...
ALBANY NY...
2013 MAY: 1 DAY
2013 JUNE: 4 DAYS
2013 JULY: 6 DAYS
2012: 13 DAYS
2011: 8 DAYS
2010: 14 DAYS
NORMAL: 10 DAYS
RECORD HIGHS: (DATE BACK TO 1874)
JULY 17: 99 DEGREES 1900
JULY 18: 100 DEGREES 1953
JULY 19: 97 DEGREES 1904
GLENS FALLS NY...
2013 MAY: 1 DAY
2013 JUNE: 2 DAYS
2013 JULY: 3 DAYS
2012: 8 DAYS
RECORD HIGHS: (DATE BACK TO 1949)
JULY 17: 99 DEGREES 1953
JULY 18: 97 DEGREES 1953
JULY 19: 95 DEGREES 1977
POUGHKEEPSIE NY...
2013 MAY: 3 DAY
2013 JUNE: 4 DAYS
2013 JULY: 7 DAYS
2012: 22 DAYS
RECORD HIGHS: (DATE BACK TO 1949)
JULY 17: 98 DEGREES 2006
JULY 18: 100 DEGREES 1991
JULY 19: 102 DEGREES 1991
BENNINGTON VT...
2013 MAY: NONE
2013 JUNE: NONE
2013 JULY: 1 DAY
2012: 7 DAYS
PITTSFIELD MA...
2013 MAY: NONE
2013 JUNE: NONE
2013 JULY: NONE
2012: 3 DAYS
&&
.EQUIPMENT...
KENX NATIONAL WEATHER SERVICE DOPPLER RADAR WILL BE UNAVAILABLE
THROUGH EARLY AUGUST. A MAJOR HARDWARE FAILURE WITH THE RADAR HAS
BEEN IDENTIFIED. FIXING THIS WILL REQUIRE HEAVY DUTY EQUIPMENT AND
A TEAM OF EMPLOYEES FROM THE RADAR OPERATIONS CENTER. WE APOLOGIZE
FOR THE INCONVENIENCE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM EDT THIS
EVENING FOR NYZ064>066.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...NAS
NEAR TERM...NAS
SHORT TERM...SNYDER
LONG TERM...IRL
AVIATION...BGM
FIRE WEATHER...SNYDER
HYDROLOGY...SNYDER
CLIMATE...WFOALY
EQUIPMENT...WFOALY
AREA FORECAST DISCUSSION
NWS ALBANY NY
1240 AM EDT THU JUL 18 2013
.SYNOPSIS...
HIGH PRESSURE AT ALL LEVELS OF THE ATMOSPHERE...WILL RECEDE FROM
THE MIDWEST TO THE ATLANTIC SEABOARD BY FRIDAY. A WEAK BOUNDARY WILL
DRIFT INTO AND OUT THE SAINT LAWRENCE TONIGHT AND
THURSDAY...TRIGGERING SCATTERED THUNDERSTORMS. OTHERWISE THE HEAT
AND HUMIDITY WILL PERSIST INTO UGH SATURDAY. A STRONG COLD FRONT
WILL PUSH THROUGH THE REGION SATURDAY...TRIGGERING THUNDERSTORMS AND
USHERING IN MORE A MORE SEASONABLE AIR MASS INTO OUR REGION TO START
THE NEW WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 1230 AM EDT...RADARS STILL INDICATING WIDELY SCATTERED SHOWER
ACTIVITY ACROSS THE ADIRONDACKS...EASTWARD INTO SOUTHERN VERMONT.
THESE APPEARED TO BE TIED INTO A WEAK BOUNDARY JUST TO NORTH OF THIS
REGION. INTERESTING THE EXPERIMENTAL HRRR HAS INDICATED A BROKEN
LINE OF SHOWERS AND POSSIBLY THUNDERSTORMS WORKING SOUTH THROUGH THE
CAPITAL REGION AND EVEN POINTS SOUTH OVERNIGHT.
WHILE THIS SCENARIO CANNOT BE RULED OUT...WE LEAN AGAINST IT SINCE
OUR RAOB INDICATED OUR MID LEVELS REMAINED CAPPED (VERY WARM
TEMPERATURES AROUND +10C AROUND 10,000 FEET) WHICH HAS BEEN ABLE TO
SUPPRESS CONVECTION THUS FAR. ALSO...WE HAVE LOST THE HEATING OF THE
DAY AND THE FRONT SHOULD STAY NORTH. THERE WAS ONE INTERESTING
FEATURE ON THE H20 VAPOR LOOP...A DISTINCT DRY PUNCH WELL TO OUR
NORTH WHICH COULD ALSO BE CONTRIBUTING TO THE SHOWER ACTIVITY. THIS
FEATURE SHOULD ALSO STAY TO THE NORTH.
WE DID EXTENT ISOLATED COVERAGE OF SHOWERS (AND SLIGHT CHANCE OF
THUNDERSTORMS) SOUTH TO ABOUT SARATOGA SPRINGS FOR A COUPLE OF
HOURS...WHILE KEEPING AREAS FROM THE CAPITAL DISTRICT SOUTHWARD DRY
(POPS LESS THAN 15 PERCENT).
THIS LEAVES US WITH AN OPPRESSIVE NIGHT. TEMPERATURES WERE STILL
OVER 80S IN THE CAPITAL DISTRICT...AND CLOSE TO 80 ACROSS MOST OTHER
AREAS. DEWPOINTS WERE AROUND 70. AND NOW WE ALSO HAVE SOME HAZE TON
CONTEND WITH.
THERE WAS STILL A LITTLE BREEZE OUT OF THE WEST WHICH COULD KEEP UP
IN SOME AREAS ALL NIGHT LONG.
FOR ALL THE ABOVE REASONS...RAISED TEMPERATURES A COUPLE DEGREES
ACROSS MANY AREAS. THIS WOULD MEAN OVERNIGHT LOWS WOULD ONLY FALL
TO ABOUT THE MID 70S FROM ALBANY SOUTHWARD...CLOSER TO 70 IN
OUTLYING AREAS. THESE VALUES WILL AVERAGE MORE THAN 10 DEGREES ABOVE
NORMAL FOR THE TIME OF YEAR.
THURSDAY...THE CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE ON THE
INCREASE DURING THE AFTERNOON. THE UPPER LEVEL HIGH PRESSURE WILL BE
SUPPRESSED TO THE SOUTH. THIS WILL CHANGE OUR FLOW TO ZONAL FLOW.
THIS COULD ALLOW FOR A DISTURBANCE OR TWO EMBEDDED IN THE INCREASING
FLOW TO MOVE THROUGH AND PRODUCE SCATTERED CONVECTION MAINLY DURING
THE AFTERNOON AND EVENING. MODELS ARE SHOWING DECENT CAPE ACROSS THE
REGION FROM 1000 J/KG TO 2500 J/KG.
TEMPERATURES ON THURSDAY WILL ONLY AGAIN BE HOT WITH TEMPERATURES
ABOVE 90 ACROSS THE GREATER CAPITAL REGION SOUTHWARD. WILL LIKELY
HOIST HEAT ADVISORIES...ESPECIALLY ACROSS THE SOUTH.
THURSDAY NIGHT...ANY SHOWERS AND THUNDERSTORMS SHOULD DIMINISH WITH
THE LOSS OF HEATING. LOWS THURSDAY NIGHT WILL BE IN THE UPPER 60S
TO LOWER 70S.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ONE MORE HOT DAY...THEN THE HEAT BREAKS...
BY FRIDAY THE 500HPA RIDGE CENTER IS ALONG THE MID ATLC COAST
WITH A ZONAL W FLOW ACROSS THE N TIER OF THE USA. EMBEDDED IN THIS
FLOW IS A SHORT WV FM LK HURON TWRD CHI FRI MORNING. AT SFC A
CDFNT IS MOVING INTO UPR GRTLKS AS THE BERMUDA HIGH HAS MOVED
OFFSHORE. DURING THE DAY FRIDAY THE APPROACHING SHORT WV BUILDS
THE RIDGE SLIGHTLY INTO THE RGN AND INCR WSW FLOW. WSW FLOW WILL
RESULT IN ADDITIONAL DIABATIC WARMING EAST OF APPALACHIANS. WITH
PS TO MS SKIES...TEMPS MAY REACH MAX VALUES FOR THIS STRETCH...WITH
90S COMMON AND MID TO UPPER 90S IN VALLEYS. ONLY FACTOR THAT COULD
CUT THEM BACK IS AMOUNT OF CONVECTIVELY INDUCED CLOUD COVER. TD
WILL REMAIN IN THE 70S AND HEAT ADVISORIES OR POSSIBLE WARNINGS
MAY BE NEEDED AGAIN FOR FRI.
NAM MODEL SOUNDINGS REASSERT A CAP ACROSS RGN FRI AT 650 HPA WITH
2600 J/KG OF CAPE IS TRAPPED UNDER IT. GFS HAS SIMILAR CAP AT
740HPA...AND CAPES FM 1000-2200 J/KG. BOTH MODELS 500HPA TEMPS INCR
BACK TO -6C TO -7C FRI.
250HPA JET REMAINS WELL NORTH OF RGN MUCH OF FRI. GFS BRINGS FCA
UNDER THE INFLUENCE OF THE RIGHT ENTRANCE RGN FRI NT...WITH AREAS OF
DIVERGENCE (FORCING) MOVING INTO N TIER LATE FRI. THE NAM IS
SLOWER IN THIS TIMING. BOTH MODELS BRING 40-50KT 850HPA WSW JET INTO
THE ST LAWRENCE VLY BY FRI EVNG.
POPS IN MOST GUIDANCE SUITE ALONG LINES OF 25-35PCT FRI. WHILE CAPES
ARE LARGE...THEY WILL BE LARGELY CAPPED TILL LATE INTO THE AFTN OR
EARLY EVENING. THEN SCT TSTMS DIURNALLY AND ELEVATED TRRN DRIVEN
WILL POKE THROUGH THE CAP. TSTMS WILL BE SUSTAINED OVERNIGHT BY
BOUNDARY INTERACTIONS...INCRG DYNAMIC FORCING AND THE APPROACHING
CDFNT. SPC HAS DAY 3 SLIGHT RISK JUST TOUCHING NW PORTIONS OF
FCA...WITH THESE INCR DYNAMICS FRI NT AND WINDS THE PRIMARY CONCERN.
FRIDAY NIGHT WILL BE ANOTHER SULTRY NIGHT WITH TD AROUND 70 AND LOWS
FALLING ONLY TO THE 70S.
SATURDAY WILL BRING AN END TO THE OPPRESSIVE HEAT IN THE FCA. CDFNT
WILL MOVE INTO THE ST LAWRENCE VLY...THEN SE ACROSS THE FCA SAT. A
PREFRONTAL TROF AHEAD OF THIS CDFNT WILL INITIATE CONVECTION.
THE NAM/GEM BRINGS THESE FEATURES THROUGH DURING THE MORNING...WHILE
THE GFS DOES SO DURING PEAK HEATING OF THE DAY IN THE AFTN.
SPC HAS FCA IN DAY 4 OUTLOOK SVR...HWVR TIMING OF CDFNT WILL DICTATE
LOCATION AND MAGNITUDE OF TSTM RESPONSE. 850 JET OF 25-40 KTS AND
RIGHT ENTIRE REGION OF 250 JET LINE UP0 ACROSS RGN AS CDFNT SHIFTS
S.
ATTM THE THREAT IS GREATEST ACROSS THE S HALF FCA...AS MOST GUIDANCE
BRINGS IT THROUGH THE N AREAS BEFORE BETTER DYNAMICS ALIGN WITH THE
CDFNT AND MAX HEATING. THIS WILL BE REFINED WITH ECMWF IN GRIDS.
IN THE COLD FRONTS WAKE...MORE SEASONABLE AND COMFORTABLE AIR WILL
STREAM INTO FCA LATE SAT AND SAT NT. TD WILL FALL INTO THE 60S...AS
SKIES CLEAR.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
THE LONG TERM PERIOD WILL BE CHARACTERIZED BY A RETURN TO MORE
SEASONABLE TEMPERATURES AND INCREASING CHANCES FOR MAINLY
AFTERNOON/EARLY EVENING SHOWERS AND THUNDERSTORMS FOR NEXT WEEK.
AT THE START OF THE LONG TERM PERIOD...LONG RANGE GUIDANCE FROM THE
12Z GFS/ECMWF/GGEM ARE IN GOOD AGREEMENT WITH THE PASSAGE OF THE
COLD FRONT THROUGH THE FORECAST AREA BY SUNDAY MORNING. THIS COLD
FRONTAL PASSAGE WILL MARK AN END TO THE HEAT WAVE ACROSS THE
FORECAST AREA...WHILE ALSO USHERING IN REFRESHINGLY LOWER HUMIDITY
LEVELS AS DEWPOINTS DROP INTO THE MID TO UPPER 50S. A BROAD AREA OF
CANADIAN HIGH PRESSURE WILL GRADUALLY BUILD IN AT THE SURFACE AND
PERSIST THROUGH THE REMAINDER OF THE WEEKEND AND INTO THE BEGINNING
OF NEXT WEEK.
THE CANADIAN HIGH PRESSURE WILL SLOWLY DRIFT SOUTHWARD BY
MONDAY...ALLOWING FOR SOME WEAK SOUTHERLY/SOUTHWESTERLY RETURN FLOW
AROUND THE HIGH. THIS RETURN FLOW WILL ALLOW DEWPOINTS TO CREEP UP
SLIGHTLY TOWARDS 60 IN SOUTHERN AREAS AND GIVEN NORTHWEST FLOW
ALOFT...CANNOT RULE OUT AN ISOLATED TERRAIN-INFLUENCED
SHOWER/THUNDERSTORM OR TWO POPPING UP DURING THE AFTERNOON HOURS.
THE LONG TERM FORECAST BECOMES A LITTLE MORE UNCERTAIN BEGINNING
TUESDAY AS THE CANADIAN HIGH PRESSURE LOOSENS ITS GRIP ACROSS THE
FORECAST AREA. ALOFT...RIPPLES OF ENERGY WILL BE MOVING THROUGH THE
NORTHWEST FLOW HELPING TO TRIGGER MAINLY AFTERNOON/EARLY EVENING
SHOWERS AND THUNDERSTORMS ACROSS THE FORECAST AREA. WILL ONLY
MENTION SLIGHT CHANCE POPS AT THIS TIME AS FORCING DOES NOT APPEAR
TO BE OVERLY STRONG DURING THIS TIME PERIOD. HOWEVER...BOTH THE 12Z
ECMWF/GFS HINT AT A STRONGER SHORTWAVE MOVING THROUGH THE FLOW
THURSDAY WHICH COULD BRING AN INCREASED THREAT FOR CONVECTION BUT
THE EXACT DETAILS ARE STILL TOO EARLY TO DETERMINE AT THIS TIME.
TEMPERATURES WILL RETURN TO MORE SEASONABLE LEVELS ALONG WITH A
NOTICEABLE DECREASE IN HUMIDITY DURING THE LONG TERM PERIOD. HIGHS
WILL GENERALLY BE FROM AROUND 70 IN NORTHWEST ZONES TO THE LOWER 80S
IN SOUTHERN ZONES. LOWS WILL GENERALLY BE IN THE LOWER 50S TO LOWER
60S. TEMPERATURES AND HUMIDITY WILL SLOWLY INCREASE NEXT WEEK
WARMING INTO THE MID 80S BY THE END OF THE PERIOD WITH A RETURN TO
LOWER 60S DEWPOINTS.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
VFR CONDITIONS AT TAF LOCATIONS THROUGH THIS EVENING...WITH A
POSSIBLE LIGHT SHOWER AROUND KGFL FOR PART OF THIS EVENING. OTHER
ISOLATED CONVECTION UPSTREAM SHOULD NOT REACH THE TAF SITES THIS
EVENING...AND WILL WATCH CONVECTION IN CANADA TO SEE IF IT FLIRTS
WITH KGFL OR KALB BETWEEN 06Z-12Z BUT THAT IS DOUBTFUL AT THIS
TIME. WINDS TONIGHT SHOULD BE NEAR CALM AND SOME FOG IS POSSIBLE
AT ALL SITES AFTER 04Z-06Z THROUGH ABOUT 12Z-13Z. VFR CONDITIONS
SHOULD PREVAIL TOMORROW WITH SOME ISOLATED TO SCATTERED
THUNDERSTORM ACTIVITY POSSIBLE AFTER 20Z-22Z. WINDS TOMORROW
SHOULD BE WEST TO SOUTHWEST AT LESS THAN 10Z
WE ARE STARTING A NEW EXPERIMENTAL FORMAT FOR DISPLAYING THE
EXTENDED PORTION OF THE AVIATION DISCUSSION. THIS FORMAT BREAKS THE
EXTENDED PERIODS INTO 12-HOUR INCREMENTS. IT DOES NOT INCLUDE THE
POSSIBILITY OF IFR/VFR BUT THE POTENTIAL SENSIBLE WEATHER AND
"POTENTIAL" IMPACT THE WEATHER MIGHT CAUSE. WE HAVE OMITTED THE WORD
POTENTIAL TO KEEP THE VERBIAGE SHORTER.
WEDNESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIGNIFICANT WEATHER.
THURSDAY: MODERATE OPERATIONAL IMPACT. SLIGHT CHANCE OF RAIN AND
THUNDER STORMS.
THURSDAY NIGHT: MODERATE OPERATIONAL IMPACT. SLIGHT CHANCE OF
RAIN SHOWERS...THUNDER STORMS.
FRIDAY: MODERATE OPERATIONAL IMPACT. BREEZY SLIGHT CHANCE OF RAIN
SHOWERS...THUNDER STORMS.
FRIDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF RAIN
SHOWERS...THUNDER STORMS.
SATURDAY: HIGH OPERATIONAL IMPACT. LIKELY RAIN SHOWERS...THUNDER
STORMS.
SATURDAY NIGHT: NO OPERATIONAL IMPACT. NO SIGNIFICANT
WEATHER. SUNDAY: NO OPERATIONAL IMPACT. NO SIGNIFICANT WEATHER.
SUNDAY NIGHT: NO OPERATIONAL IMPACT. NO SIGNIFICANT WEATHER.
MONDAY: MODERATE OPERATIONAL IMPACT. SLIGHT CHANCE OF RAIN
SHOWERS...THUNDER STORMS.
&&
.FIRE WEATHER...
HIGH PRESSURE AT ALL LEVELS OF THE ATMOSPHERE...WILL RECEDE FROM
THE MIDWEST TO THE ATLANTIC SEABOARD BY FRIDAY. A WEAK BOUNDARY WILL
DRIFT INTO AND OUT THE SAINT LAWRENCE TONIGHT AND
THURSDAY...TRIGGERING SCATTERED THUNDERSTORMS. OTHERWISE THE HEAT
AND HUMIDITY WILL PERSIST INTO UGH SATURDAY. A STRONG COLD FRONT
WILL PUSH THROUGH THE REGION SATURDAY...TRIGGERING THUNDERSTORMS AND
USHERING IN MORE A MORE SEASONABLE AIR MASS INTO OUR REGION TO START
THE NEW WEEK.
RH VALUES WILL REMAIN ELEVATED FOR THE NEXT SEVERAL DAYS. LOOK FOR
FULL RECOVERIES AT NIGHT AND RH VALUES ONLY DROPPING TO 40 TO 60
PERCENT EACH AFTERNOON (HIGHEST ACROSS THE MOUNTAINS).
SCATTERED MAINLY AFTERNOON AND EVENING THUNDERSTORMS ARE POSSIBLE
INTO FRIDAY NIGHT. MORE NUMEROUS SHOWERS AND THUNDERSTORMS ARE
POSSIBLE SATURDAY. HEAVY RAINFALL WILL BE POSSIBLE WITH ANY
THUNDERSTORMS...ESPECIALLY SATURDAY.
&&
.HYDROLOGY...
SCATTERED MAINLY AFTERNOON AND EVENING THUNDERSTORMS ARE POSSIBLE
INTO FRIDAY NIGHT. MORE NUMEROUS SHOWERS AND THUNDERSTORMS ARE
POSSIBLE SATURDAY. HEAVY RAINFALL WILL BE POSSIBLE WITH ANY
THUNDERSTORMS...ESPECIALLY SATURDAY.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.CLIMATE...
TO ACCESS HEAT RELATED CLIMATE DATA INCLUDING HEAT WAVES...NUMBER
90+ DEGREES DAYS AND 100+ DEGREES DAYS...PLEASE VISIT
WWW.WEATHER.GOV/ALY/CLIMATE (ALL LOWER CASE) AND GO TO THE
RECORDS... EXTREMES... PAGE FOR ALBANY.
NUMBER OF 90+ DEGREE DAYS AND RECORD HIGHS...
ALBANY NY...
2013 MAY: 1 DAY
2013 JUNE: 4 DAYS
2013 JULY: 6 DAYS
2012: 13 DAYS
2011: 8 DAYS
2010: 14 DAYS
NORMAL: 10 DAYS
RECORD HIGHS: (DATE BACK TO 1874)
JULY 17: 99 DEGREES 1900
JULY 18: 100 DEGREES 1953
JULY 19: 97 DEGREES 1904
GLENS FALLS NY...
2013 MAY: 1 DAY
2013 JUNE: 2 DAYS
2013 JULY: 3 DAYS
2012: 8 DAYS
RECORD HIGHS: (DATE BACK TO 1949)
JULY 17: 99 DEGREES 1953
JULY 18: 97 DEGREES 1953
JULY 19: 95 DEGREES 1977
POUGHKEEPSIE NY...
2013 MAY: 3 DAY
2013 JUNE: 4 DAYS
2013 JULY: 7 DAYS
2012: 22 DAYS
RECORD HIGHS: (DATE BACK TO 1949)
JULY 17: 98 DEGREES 2006
JULY 18: 100 DEGREES 1991
JULY 19: 102 DEGREES 1991
BENNINGTON VT...
2013 MAY: NONE
2013 JUNE: NONE
2013 JULY: 1 DAY
2012: 7 DAYS
PITTSFIELD MA...
2013 MAY: NONE
2013 JUNE: NONE
2013 JULY: NONE
2012: 3 DAYS
&&
.EQUIPMENT...
KENX NATIONAL WEATHER SERVICE DOPPLER RADAR WILL BE UNAVAILABLE
THROUGH EARLY AUGUST. A MAJOR HARDWARE FAILURE WITH THE RADAR HAS
BEEN IDENTIFIED. FIXING THIS WILL REQUIRE HEAVY DUTY EQUIPMENT AND
A TEAM OF EMPLOYEES FROM THE RADAR OPERATIONS CENTER. WE APOLOGIZE
FOR THE INCONVENIENCE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM EDT THIS
EVENING FOR NYZ064>066.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...NAS
NEAR TERM...NAS
SHORT TERM...SNYDER
LONG TERM...IRL
AVIATION...NAS
FIRE WEATHER...SNYDER
HYDROLOGY...SNYDER
CLIMATE...WFOALY
EQUIPMENT...WFOALY
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
940 PM EDT FRI JUL 19 2013
.DISCUSSION...
THE BULK OF TODAY`S ROUND OF DIURNAL CONVECTION HAS LARGELY CHANGED
OVER TO DEBRIS PRECIP. MEAN FLOW HAS SHIFTED TO THE S/SW...PUTTING E
CENTRAL FL IN THE PATH OF THE "BLOWBACK" PRECIP. SEVERAL STATIONS
REPORTING BTWN 1.25" AND 1.50" WITH KDAB RECEIVING OVER 2.00" OF
PRECIP (UPDATED FROM THE EVNG RTP). RADAR SHOWS A LARGE SWATH OF
ESTIMATED 1.00"-1.25" EXTENDING FROM LAKE KISSIMMEE TO DAYTONA
BEACH. MAX RAINFALL BTWN HOLOPAW AND DEER PARK WITH LCL AMOUNTS BTWN
3.0" AND 4.0". OTHER LCL MAXES INCLUDE THE I-4/I-95 INTERCHANGE IN
VOLUSIA COUNTY AND WEST OF LAKE GRIFFIN IN NW LAKE COUNTY WITH
2.0"-2.5".
LATEST RUC ANALYSIS SHOWS A RESPECTABLE AMOUNT OF ISENTROPIC LIFT
OVER THE CENTRAL/SRN PENINSULA FOR MID SUMMER. WHILE THE RADAR TREND
INDICATES THE DEBRIS PRECIP IS GRADUALLY ERODING...THE LOW/MID LVL
SUPPORT SHOULD MAINTAIN IT THRU MIDNIGHT. WILL UPDATE TO REMOVE
TSRAS FROM THE FCST AND REPLACE WITH -RA FOR MOST OF THE CWA...
INCREASING POPS 10PCT AREAWIDE.
&&
.AVIATION...
THRU 20/04Z...NW OF KVRB-KOBE AREAS IFR CIGS/VSYBS IN RA/-RA/BR...
SE OF KVRB-KOBE VFR WITH CIGS AOA FL120. BTWN 20/04Z-20/14Z...VFR
ALL SITES...CIGS AOA FL120. BTWN 20/14Z-20/16Z...SFC WNDSHFT FM S TO
E/SE CSTL SITES AOB 12KTS ASSOCD WITH EAST COAST SEA BREEZE. BTWN
20/17-20/20Z...SFC WND SHFT FM S TO E/SE INTERIOR SITES ASSOCD WITH
THE INLAND PROPAGATION OF THE EAST COAST SEA BREEZE...NMRS MVFR
SHRAS/SCT IFR TSRAS DVLPG W OF KTIX-KOBE...SCT MVFR SHRAS/IFR TSRAS
DVLPG E OF KTIX-KOBE.
NOTE TO USERS: KSUA ASOS DAMAGED IN CG STRIKE...SFC OBS AND TAF AMD
NOT AVBL THRU 20/11Z.
&&
.MARINE...
OFFSHORE MOVING RAIN WITH EMBEDDED SHRAS THRU MIDNIGHT FROM
SEBASTIAN INLET NWD. SFC/LOW LVL RIDGE AXIS EXTENDING FROM THE WRN
ATLC ACRS CENTRAL FL WILL GENERATE A GENTLE TO MODERATE SRLY BREEZE
THRU DAYBREAK. SEAS 2FT NEARSHORE AND 2-3FT OFFSHORE. COMBO OF
OFFSHORE SFC/BNDRY LYR WINDS AND THE BAHAMA SHADOW EFFECT WILL
GENERATE SHORT PD CHOP OUT TO 20NM AND S OF SEBASTIAN INLET 20-60NM.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
FORECAST....BRAGAW
IMPACT WX...CRISTALDI
AREA FORECAST DISCUSSION
NWS MIAMI FL
210 PM EDT THU JUL 18 2013
.AVIATION...
MAIN CONVECTION OVER EASTERN PORTIONS OF PENINSULA HAS NOW
DIMINISHED AS ATMOSPHERE HAS AT LEAST TEMPORARILY STABILIZED AS
LOW LEVELS HAVE BECOME RAIN COOLED. FOR WESTERN
AREAS...THUNDERSTORM COMPLEX FROM THE GULF HAS INTRUDED INTO
COASTAL AREAS AND APPEARS ON TRACK TO IMPACT MOST OF WESTERN HALF
OF SOUTH FLORIDA THROUGH LATE THIS AFTERNOON. TAFS REFLECT THE
ABOVE THINKING...WITH VCSH FOR ALL EASTERN TERMINALS...AND VCTS
WITH TEMPO TSRA FOR KAPF...ALL THROUGH 0Z.
THEREAFTER...PRECIPITATION SHOULD DIURNALLY WANE. FOR
FRIDAY...RIBBON OF DRIER AIR/SUBSIDENCE SHOULD CROSS SOUTH
FLORIDA...THUS SHWR CHANCES ARE AROUND 30 PERCENT OR SO...AND DONT
WARRANT MENTION IN TAFS. VFR CONDITIONS SHOULD BE MOST
PREVALENT...BUT PERIODS OF SIGNIFICANT RESTRICTIONS WILL ACCOMPANY
THUNDERSTORMS. WHERE COVERAGE IS MOST WIDESPREAD...KAPF...TEMPO
MVFR CONDITIONS HAVE BEEN INTRODUCED.
WINDS WILL BE SOUTHEAST AROUND 10-15 KTS TODAY AND FRIDAY...BUT
AROUND 5 KTS OVERNIGHT. MUCH GUSTIER WINDS OUT OF VARIABLE
DIRECTIONS CAN BE EXPECTED AROUND STRONGER CONVECTION.
&&
.PREV DISCUSSION... /ISSUED 1058 AM EDT THU JUL 18 2013/
UPDATE...
LARGE SCALE CONVECTION CONVECTION CONTINUES ACROSS THE EASTERN
GULF...ACROSS THE FLORIDA STRAITS AND EASTWARD INTO THE BAHAMAS.
LOCALLY...HEAVY SHOWERS AND THUNDERSTORMS CONTINUE ACROSS THE
LOCAL GULF WATERS...BISCAYNE BAY AND PORTIONS OF THE EAST COAST
METRO AREAS AND THE ADJACENT ATLANTIC WATERS. THE 12Z SOUNDING INDICATED
DEEP TROPICAL MOISTURE CONTINUING ACROSS THE REGION WITH A PWAT
NEAR 2.2 INCHES.
THE SHORT TERM FORECAST FOR THE LATE MORNING AND AFTERNOON WAS
UPDATED TO REFLECT THE INCREASED COVERAGE OF SHOWERS AND
THUNDERSTORMS ACROSS THE REGION...BOTH INDICATED BY LOCAL
OBSERVATIONS AND RECENT MESO-SCALE MODEL GUIDANCE. RECENT RADAR
RETURNS AND SATELLITE IMAGERY INDICATE ON-GOING CONVECTION ACROSS
THE FLORIDA STRAITS LIFTING NORTHWARD. THIS IS REFLECTED IN THE
MESO-SCALE GUIDANCE AS WELL. IN ADDITION THE MESO-SCALE GUIDANCE
INDICATES WIDESPREAD SHOWERS ACROSS THE PENINSULA STARTING AROUND
16Z WITH STORMS FORECAST TO LIFT NORTHWARD. TO SUM UP...THE
FORECAST FOR THE LATE MORNING THROUGH THE AFTERNOON IS FOR INCREASING
COVERAGE OF SHOWERS AND THUNDERSTORMS WITH A GENERAL NORTHWARD
MOTION OF THE STORMS. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE IN
ISOLATED AREAS.
60
PREV DISCUSSION... /ISSUED 728 AM EDT THU JUL 18 2013/
AVIATION...
CHALLENGING TAF FORECAST. GLOBAL MODELS SHOW AN ACTIVE DAY AREA
WIDE, WHILE THE HRRR ONLY SHOWS IT BECOMING ACTIVE TOWARDS THE GULF
COAST...SO LESS CONFIDENCE ON TSTORMS EAST COAST SITES. HAVE A MORNING
TEMPO OF MVFR SHRA/VCTS EAST COAST SITES. FOR KAPF, HAVE AN AFTERNOON
TEMPO OF TSRA/MVFR. HOWEVER, IFR COULD OCCUR AT ANY GIVEN TERMINAL
SHOULD HEAVY SHOWERS OR TSTORMS IMPACT THOSE AREA, BUT CONFIDENCE
IS TOO LOW TO INCLUDE IN THE TAFS AT THIS TIME. LIGHT-CALM WINDS
EARLY THIS MORNING WILL BECOME SE AT 5-10 KT EAST COAST AND S-SE
5-10 KT AT KAPF.
GREGORIA
PREV DISCUSSION... /ISSUED 330 AM EDT THU JUL 18 2013/
DISCUSSION...
AN UPPER LEVEL LOW REMAINS ACROSS THE EASTERN GULF...AND A LOW
LEVEL/SURFACE TROUGH BISECTS THE REGION EARLY THIS MORNING. THE
UPPER LEVEL LOW WILL BEGIN TO SHIFT TO THE NORTHWEST...AND THE LOW
LEVEL TROUGH WILL ALSO LIFT NORTHWESTWARD INTO CENTRAL FLORIDA
DURING THE DAY TODAY. THE FOCUS FOR SHOWERS THIS MORNING SHOULD BE
ACROSS EXTREME NORTHEAST BROWARD AND ACROSS EASTERN PALM BEACH
COUNTY ALONG AND AHEAD OF THE TROUGH AXIS. OTHER SCATTERED LIGHT
SHOWERS WERE MOVING NORTHWARD OVER THE FLORIDA STRAITS AND FLORIDA
KEYS AND INTO DEEP SOUTH FLORIDA.
PWATS WILL REMAIN ABOVE 2 INCHES TODAY. THE STEERING FLOW IS
FORECAST TO BECOME WEAK OUT OF THE SOUTHWEST BY THIS AFTERNOON. SO
OVERALL STORM MOTION WILL BE VERY SLOW. GLOBAL AND HIGH RES MODEL
GUIDANCE IS NOT TOO BULLISH ON HEAVY RAINFALL FOR THE EAST COAST
METRO AREAS PAST EARLY THIS MORNING AS THE FOCUSING MECHANISM
SHIFTS OUT OF THE REGION. HOWEVER...WITH SO MUCH RAIN FALLING OVER
THE PAST SEVERAL DAYS...IT WILL NOT TAKE MUCH TO CREATE MORE
FLOODING. SO A SLIGHT FLOOD RISK WILL REMAIN IN THE HWO FOR THE
ENTIRE REGION. WITH A LITTLE MORE DAYTIME HEATING EXPECTED THIS
AFTERNOON...WEAK SEA BREEZE BOUNDARIES MAY DEVELOP. SHOWERS AND
STORMS WOULD THEN LIKELY FOCUS ACROSS THE NORTHERN INTERIOR AND
TOWARDS THE GULF COAST...WHERE THE DEEPER MOISTURE WILL RESIDE.
THE SUBTROPICAL RIDGE WILL BEGIN TO BUILD IN FROM THE WEST TONIGHT
AND INTO FRIDAY. SOMEWHAT DRIER AIR WILL PUSH NORTHWEST ACROSS
THE REGION BEHIND THE LOW LEVEL TROUGH AND AHEAD OF A TROPICAL
WAVE. SO RAIN CHANCES WILL BE MUCH LOWER...ESPECIALLY SOUTHEAST.
A TROPICAL WAVE CURRENTLY NEAR PUERTO RICO WILL MOVE WEST AND ACROSS
SOUTH FLORIDA ON SATURDAY...WITH PWATS PROJECTED TO INCREASE TO
2.1-2.3 INCHES. SO NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS ARE
FORECAST FOR SOUTH FLORIDA AS THE WAVE MOVES THROUGH. THE
SUBTROPICAL RIDGE WILL THEN CONTINUE TO BUILD INTO THE REGION SUNDAY
THROUGH THE MIDDLE OF NEXT WEEK. DRIER AIR IS ALSO FORECAST TO PUSH
INTO THE REGION...AND RAINFALL CHANCES ARE FORECAST TO BE BELOW
NORMAL THROUGH THE MIDDLE OF THE WEEK. TEMPERATURES WILL SLOWLY WARM
INTO THE LOW 90S FOR THE COASTAL AREAS AND LOW/MID 90S INTERIOR.
WITH DEWPOINTS IN THE MID 70S...HEAT INDICES ARE FORECAST TO BE IN
THE UPPER 90S TO AROUND 100 FOR THE COASTAL AREAS AND 100-105
DEGREES ACROSS THE INTERIOR.
AVIATION...06Z TAFS.
AN AREA OF SHOWERS AND A FEW THUNDERSTORMS WILL
CONTINUE JUST NE OF KFXE NEXT HOUR OR SO BEFORE MOVING NORTH
TOWARDS KPBI, SO ADDED VCTS FOR KFXE NEXT 2 HR WITH THEN A TEMPO
OF TSRA/MVFR FOR KPBI FROM 08-10Z. OTHERWISE, VFR WILL PREVAIL
ACROSS THE AREA. HOWEVER, ADDITIONAL ACTIVITY IS EXPECTED TO
DEVELOP ESPECIALLY AFTER SUNRISE SO KEPT WITH VCTS. LIGHT WINDS
THIS MORNING WILL BECOME SE 5-10 KT THIS AFTERNOON, EXCEPT S AT
KAPF. /GREGORIA
MARINE...
A WEAK SURFACE TROUGH WILL CONTINUE TO LIFT NORTHWESTWARD ACROSS
THE REGION THIS MORNING...AND THE PRESSURE GRADIENT AND REGIONAL
WINDS ARE FORECAST TO SLOWLY SUBSIDE WITH THE GULF AND ATLANTIC
SEAS FORECAST TO SLOWLY SUBSIDE TODAY. OTHERWISE...WINDS AND SEAS
ARE EXPECTED TO REMAIN WELL BELOW ADVISORY LEVELS THROUGH THE
FORECAST PERIOD.
FIRE WEATHER...
LIGHT EAST TO SOUTHEAST FLOW AND MOIST CONDITIONS THROUGH THE
PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 75 87 78 87 / 40 30 30 50
FORT LAUDERDALE 77 88 78 88 / 40 30 40 50
MIAMI 76 88 78 88 / 50 30 40 50
NAPLES 74 91 76 89 / 50 40 30 50
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...60/BD
AVIATION/RADAR...59/RM
AREA FORECAST DISCUSSION
NWS MIAMI FL
1058 AM EDT THU JUL 18 2013
.UPDATE...
LARGE SCALE CONVECTION CONVECTION CONTINUES ACROSS THE EASTERN
GULF...ACROSS THE FLORIDA STRAITS AND EASTWARD INTO THE BAHAMAS.
LOCALLY...HEAVY SHOWERS AND THUNDERSTORMS CONTINUE ACROSS THE
LOCAL GULF WATERS...BISCAYNE BAY AND PORTIONS OF THE EAST COAST
METRO AREAS AND THE ADJACENT ATLANTIC WATERS. THE 12Z SOUNDING INDICATED
DEEP TROPICAL MOISTURE CONTINUING ACROSS THE REGION WITH A PWAT
NEAR 2.2 INCHES.
THE SHORT TERM FORECAST FOR THE LATE MORNING AND AFTERNOON WAS
UPDATED TO REFLECT THE INCREASED COVERAGE OF SHOWERS AND
THUNDERSTORMS ACROSS THE REGION...BOTH INDICATED BY LOCAL
OBSERVATIONS AND RECENT MESO-SCALE MODEL GUIDANCE. RECENT RADAR
RETURNS AND SATELLITE IMAGERY INDICATE ON-GOING CONVECTION ACROSS
THE FLORIDA STRAITS LIFTING NORTHWARD. THIS IS REFLECTED IN THE
MESO-SCALE GUIDANCE AS WELL. IN ADDITION THE MESO-SCALE GUIDANCE
INDICATES WIDESPREAD SHOWERS ACROSS THE PENINSULA STARTING AROUND
16Z WITH STORMS FORECAST TO LIFT NORTHWARD. TO SUM UP...THE
FORECAST FOR THE LATE MORNING THROUGH THE AFTERNOON IS FOR INCREASING
COVERAGE OF SHOWERS AND THUNDERSTORMS WITH A GENERAL NORTHWARD
MOTION OF THE STORMS. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE IN
ISOLATED AREAS.
60
&&
.PREV DISCUSSION... /ISSUED 728 AM EDT THU JUL 18 2013/
AVIATION...
CHALLENGING TAF FORECAST. GLOBAL MODELS SHOW AN ACTIVE DAY AREA
WIDE, WHILE THE HRRR ONLY SHOWS IT BECOMING ACTIVE TOWARDS THE GULF
COAST...SO LESS CONFIDENCE ON TSTORMS EAST COAST SITES. HAVE A MORNING
TEMPO OF MVFR SHRA/VCTS EAST COAST SITES. FOR KAPF, HAVE AN AFTERNOON
TEMPO OF TSRA/MVFR. HOWEVER, IFR COULD OCCUR AT ANY GIVEN TERMINAL
SHOULD HEAVY SHOWERS OR TSTORMS IMPACT THOSE AREA, BUT CONFIDENCE
IS TOO LOW TO INCLUDE IN THE TAFS AT THIS TIME. LIGHT-CALM WINDS
EARLY THIS MORNING WILL BECOME SE AT 5-10 KT EAST COAST AND S-SE
5-10 KT AT KAPF.
GREGORIA
PREV DISCUSSION... /ISSUED 330 AM EDT THU JUL 18 2013/
DISCUSSION...
AN UPPER LEVEL LOW REMAINS ACROSS THE EASTERN GULF...AND A LOW
LEVEL/SURFACE TROUGH BISECTS THE REGION EARLY THIS MORNING. THE
UPPER LEVEL LOW WILL BEGIN TO SHIFT TO THE NORTHWEST...AND THE LOW
LEVEL TROUGH WILL ALSO LIFT NORTHWESTWARD INTO CENTRAL FLORIDA
DURING THE DAY TODAY. THE FOCUS FOR SHOWERS THIS MORNING SHOULD BE
ACROSS EXTREME NORTHEAST BROWARD AND ACROSS EASTERN PALM BEACH
COUNTY ALONG AND AHEAD OF THE TROUGH AXIS. OTHER SCATTERED LIGHT
SHOWERS WERE MOVING NORTHWARD OVER THE FLORIDA STRAITS AND FLORIDA
KEYS AND INTO DEEP SOUTH FLORIDA.
PWATS WILL REMAIN ABOVE 2 INCHES TODAY. THE STEERING FLOW IS
FORECAST TO BECOME WEAK OUT OF THE SOUTHWEST BY THIS AFTERNOON. SO
OVERALL STORM MOTION WILL BE VERY SLOW. GLOBAL AND HIGH RES MODEL
GUIDANCE IS NOT TOO BULLISH ON HEAVY RAINFALL FOR THE EAST COAST
METRO AREAS PAST EARLY THIS MORNING AS THE FOCUSING MECHANISM
SHIFTS OUT OF THE REGION. HOWEVER...WITH SO MUCH RAIN FALLING OVER
THE PAST SEVERAL DAYS...IT WILL NOT TAKE MUCH TO CREATE MORE
FLOODING. SO A SLIGHT FLOOD RISK WILL REMAIN IN THE HWO FOR THE
ENTIRE REGION. WITH A LITTLE MORE DAYTIME HEATING EXPECTED THIS
AFTERNOON...WEAK SEA BREEZE BOUNDARIES MAY DEVELOP. SHOWERS AND
STORMS WOULD THEN LIKELY FOCUS ACROSS THE NORTHERN INTERIOR AND
TOWARDS THE GULF COAST...WHERE THE DEEPER MOISTURE WILL RESIDE.
THE SUBTROPICAL RIDGE WILL BEGIN TO BUILD IN FROM THE WEST TONIGHT
AND INTO FRIDAY. SOMEWHAT DRIER AIR WILL PUSH NORTHWEST ACROSS
THE REGION BEHIND THE LOW LEVEL TROUGH AND AHEAD OF A TROPICAL
WAVE. SO RAIN CHANCES WILL BE MUCH LOWER...ESPECIALLY SOUTHEAST.
A TROPICAL WAVE CURRENTLY NEAR PUERTO RICO WILL MOVE WEST AND ACROSS
SOUTH FLORIDA ON SATURDAY...WITH PWATS PROJECTED TO INCREASE TO
2.1-2.3 INCHES. SO NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS ARE
FORECAST FOR SOUTH FLORIDA AS THE WAVE MOVES THROUGH. THE
SUBTROPICAL RIDGE WILL THEN CONTINUE TO BUILD INTO THE REGION SUNDAY
THROUGH THE MIDDLE OF NEXT WEEK. DRIER AIR IS ALSO FORECAST TO PUSH
INTO THE REGION...AND RAINFALL CHANCES ARE FORECAST TO BE BELOW
NORMAL THROUGH THE MIDDLE OF THE WEEK. TEMPERATURES WILL SLOWLY WARM
INTO THE LOW 90S FOR THE COASTAL AREAS AND LOW/MID 90S INTERIOR.
WITH DEWPOINTS IN THE MID 70S...HEAT INDICES ARE FORECAST TO BE IN
THE UPPER 90S TO AROUND 100 FOR THE COASTAL AREAS AND 100-105
DEGREES ACROSS THE INTERIOR.
AVIATION...06Z TAFS.
AN AREA OF SHOWERS AND A FEW THUNDERSTORMS WILL
CONTINUE JUST NE OF KFXE NEXT HOUR OR SO BEFORE MOVING NORTH
TOWARDS KPBI, SO ADDED VCTS FOR KFXE NEXT 2 HR WITH THEN A TEMPO
OF TSRA/MVFR FOR KPBI FROM 08-10Z. OTHERWISE, VFR WILL PREVAIL
ACROSS THE AREA. HOWEVER, ADDITIONAL ACTIVITY IS EXPECTED TO
DEVELOP ESPECIALLY AFTER SUNRISE SO KEPT WITH VCTS. LIGHT WINDS
THIS MORNING WILL BECOME SE 5-10 KT THIS AFTERNOON, EXCEPT S AT
KAPF. /GREGORIA
MARINE...
A WEAK SURFACE TROUGH WILL CONTINUE TO LIFT NORTHWESTWARD ACROSS
THE REGION THIS MORNING...AND THE PRESSURE GRADIENT AND REGIONAL
WINDS ARE FORECAST TO SLOWLY SUBSIDE WITH THE GULF AND ATLANTIC
SEAS FORECAST TO SLOWLY SUBSIDE TODAY. OTHERWISE...WINDS AND SEAS
ARE EXPECTED TO REMAIN WELL BELOW ADVISORY LEVELS THROUGH THE
FORECAST PERIOD.
FIRE WEATHER...
LIGHT EAST TO SOUTHEAST FLOW AND MOIST CONDITIONS THROUGH THE
PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 85 75 87 78 / 60 30 30 30
FORT LAUDERDALE 86 77 88 78 / 70 30 20 40
MIAMI 87 76 88 78 / 70 30 20 40
NAPLES 88 74 91 76 / 60 40 30 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...60/BD
AVIATION/RADAR...59/RM
AREA FORECAST DISCUSSION
NWS MIAMI FL
728 AM EDT THU JUL 18 2013
.AVIATION...
CHALLENGING TAF FORECAST. GLOBAL MODELS SHOW AN ACTIVE DAY AREA
WIDE, WHILE THE HRRR ONLY SHOWS IT BECOMING ACTIVE TOWARDS THE GULF
COAST...SO LESS CONFIDENCE ON TSTORMS EAST COAST SITES. HAVE A MORNING
TEMPO OF MVFR SHRA/VCTS EAST COAST SITES. FOR KAPF, HAVE AN AFTERNOON
TEMPO OF TSRA/MVFR. HOWEVER, IFR COULD OCCUR AT ANY GIVEN TERMINAL
SHOULD HEAVY SHOWERS OR TSTORMS IMPACT THOSE AREA, BUT CONFIDENCE
IS TOO LOW TO INCLUDE IN THE TAFS AT THIS TIME. LIGHT-CALM WINDS
EARLY THIS MORNING WILL BECOME SE AT 5-10 KT EAST COAST AND S-SE
5-10 KT AT KAPF.
GREGORIA
&&
.PREV DISCUSSION... /ISSUED 330 AM EDT THU JUL 18 2013/
DISCUSSION...
AN UPPER LEVEL LOW REMAINS ACROSS THE EASTERN GULF...AND A LOW
LEVEL/SURFACE TROUGH BISECTS THE REGION EARLY THIS MORNING. THE
UPPER LEVEL LOW WILL BEGIN TO SHIFT TO THE NORTHWEST...AND THE LOW
LEVEL TROUGH WILL ALSO LIFT NORTHWESTWARD INTO CENTRAL FLORIDA
DURING THE DAY TODAY. THE FOCUS FOR SHOWERS THIS MORNING SHOULD BE
ACROSS EXTREME NORTHEAST BROWARD AND ACROSS EASTERN PALM BEACH
COUNTY ALONG AND AHEAD OF THE TROUGH AXIS. OTHER SCATTERED LIGHT
SHOWERS WERE MOVING NORTHWARD OVER THE FLORIDA STRAITS AND FLORIDA
KEYS AND INTO DEEP SOUTH FLORIDA.
PWATS WILL REMAIN ABOVE 2 INCHES TODAY. THE STEERING FLOW IS
FORECAST TO BECOME WEAK OUT OF THE SOUTHWEST BY THIS AFTERNOON. SO
OVERALL STORM MOTION WILL BE VERY SLOW. GLOBAL AND HIGH RES MODEL
GUIDANCE IS NOT TOO BULLISH ON HEAVY RAINFALL FOR THE EAST COAST
METRO AREAS PAST EARLY THIS MORNING AS THE FOCUSING MECHANISM
SHIFTS OUT OF THE REGION. HOWEVER...WITH SO MUCH RAIN FALLING OVER
THE PAST SEVERAL DAYS...IT WILL NOT TAKE MUCH TO CREATE MORE
FLOODING. SO A SLIGHT FLOOD RISK WILL REMAIN IN THE HWO FOR THE
ENTIRE REGION. WITH A LITTLE MORE DAYTIME HEATING EXPECTED THIS
AFTERNOON...WEAK SEA BREEZE BOUNDARIES MAY DEVELOP. SHOWERS AND
STORMS WOULD THEN LIKELY FOCUS ACROSS THE NORTHERN INTERIOR AND
TOWARDS THE GULF COAST...WHERE THE DEEPER MOISTURE WILL RESIDE.
THE SUBTROPICAL RIDGE WILL BEGIN TO BUILD IN FROM THE WEST TONIGHT
AND INTO FRIDAY. SOMEWHAT DRIER AIR WILL PUSH NORTHWEST ACROSS
THE REGION BEHIND THE LOW LEVEL TROUGH AND AHEAD OF A TROPICAL
WAVE. SO RAIN CHANCES WILL BE MUCH LOWER...ESPECIALLY SOUTHEAST.
A TROPICAL WAVE CURRENTLY NEAR PUERTO RICO WILL MOVE WEST AND ACROSS
SOUTH FLORIDA ON SATURDAY...WITH PWATS PROJECTED TO INCREASE TO
2.1-2.3 INCHES. SO NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS ARE
FORECAST FOR SOUTH FLORIDA AS THE WAVE MOVES THROUGH. THE
SUBTROPICAL RIDGE WILL THEN CONTINUE TO BUILD INTO THE REGION SUNDAY
THROUGH THE MIDDLE OF NEXT WEEK. DRIER AIR IS ALSO FORECAST TO PUSH
INTO THE REGION...AND RAINFALL CHANCES ARE FORECAST TO BE BELOW
NORMAL THROUGH THE MIDDLE OF THE WEEK. TEMPERATURES WILL SLOWLY WARM
INTO THE LOW 90S FOR THE COASTAL AREAS AND LOW/MID 90S INTERIOR.
WITH DEWPOINTS IN THE MID 70S...HEAT INDICES ARE FORECAST TO BE IN
THE UPPER 90S TO AROUND 100 FOR THE COASTAL AREAS AND 100-105
DEGREES ACROSS THE INTERIOR.
AVIATION...06Z TAFS.
AN AREA OF SHOWERS AND A FEW THUNDERSTORMS WILL
CONTINUE JUST NE OF KFXE NEXT HOUR OR SO BEFORE MOVING NORTH
TOWARDS KPBI, SO ADDED VCTS FOR KFXE NEXT 2 HR WITH THEN A TEMPO
OF TSRA/MVFR FOR KPBI FROM 08-10Z. OTHERWISE, VFR WILL PREVAIL
ACROSS THE AREA. HOWEVER, ADDITIONAL ACTIVITY IS EXPECTED TO
DEVELOP ESPECIALLY AFTER SUNRISE SO KEPT WITH VCTS. LIGHT WINDS
THIS MORNING WILL BECOME SE 5-10 KT THIS AFTERNOON, EXCEPT S AT
KAPF. /GREGORIA
MARINE...
A WEAK SURFACE TROUGH WILL CONTINUE TO LIFT NORTHWESTWARD ACROSS
THE REGION THIS MORNING...AND THE PRESSURE GRADIENT AND REGIONAL
WINDS ARE FORECAST TO SLOWLY SUBSIDE WITH THE GULF AND ATLANTIC
SEAS FORECAST TO SLOWLY SUBSIDE TODAY. OTHERWISE...WINDS AND SEAS
ARE EXPECTED TO REMAIN WELL BELOW ADVISORY LEVELS THROUGH THE
FORECAST PERIOD.
FIRE WEATHER...
LIGHT EAST TO SOUTHEAST FLOW AND MOIST CONDITIONS THROUGH THE
PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 85 75 87 78 / 70 30 30 30
FORT LAUDERDALE 86 77 88 78 / 60 30 20 40
MIAMI 87 76 88 78 / 50 30 20 40
NAPLES 88 74 91 76 / 60 40 30 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
128 AM EDT THU JUL 18 2013
.SHORT TERM /REMAINDER OF TONIGHT/...
/ISSUED AT 1105 PM EDT WED JUL 17 2013/
EASTERLY FLOW CONTINUES OVER THE AREA. ENOUGH INSTABILITY REMAIN FOR
CONVECTION TO CONTINUE FIRING OVER THE AREA. THOUGH MUCH OF THE
THUNDERSTORM ACTIVITY OVER NORTH GEORGIA HAS DIMINISHED TO
SHOWERS...A FEW EMBEDDED THUNDERSTORMS CONTINUE TO DEVELOP. THE
SOUTHERN PORTION OF THE FORECAST AREA HAS BECOME MORE ACTIVE WITH
THUNDERSTORM DEVELOPMENT...MAINLY ALONG SOME OF THE BOUNDARIES FROM
PREVIOUS STORMS TO THE NORTH. THE ANTICIPATION IS FOR THESE STORMS
TO ALL WEAKEN AND DIMINISH OVER THE NEXT FEW HOURS...AND MOSTLY
CLOUDY CLOUDY SKIES TO CONTINUE INTO MORNING.
&&
.PREVIOUS DISCUSSION...ISSUED AT 330 PM...
SHORT TERM/TONIGHT THROUGH THURSDAY NIGHT/...
CURRENT SATELLITE LOOP SHOWS MAIN EASTERN WAVE MOVING INTO NE GA AT
THE MOMENT. THE CURRENT RADAR LOP SHOWS SHOWERS AND ISOLATED
THUNDERSTORMS POPPING UP ACROSS NE GA WHICH IS DEFINITELY BEING
GENERATED BY THIS WAVE. THE MAIN ENERGY FROM THIS WAVE IS EXPECTED
TO STAY ACROSS NORTH GA BUT BOTH OUR LOCAL WRF AND THE HRRR SHOW A
BIT MORE DIURNALLY DRIVEN POP UP SHRA/TSRA ACROSS THE STATE THROUGH
02-04Z TONIGHT. THE SURFACE TO UPPER LEVEL RIDGE KEEPS OUR AREA IN
MOIST EASTERLY FLOW THROUGH THE SHORT TERM. THE MODELS ARE SHOWING
ANOTHER WEAKER WAVE MOVING ACROSS THE AREA THU IN THIS EASTERLY
FLOW. WITH THIS IN MIND SHOULD SEE ANOTHER DIURNALLY DRIVEN
CONVECTIVE DAY THU. THERE IS VERY LITTLE SHEAR IN THIS ATMOSPHERE
BUT THE CAPES AND LIS BOTH PEAK BETWEEN 18Z AND 00Z THIS AFTERNOON
AND THURSDAY. TODAY SHOULD BE THE WARMEST DAY THIS WEEK WITH RISING
THICKNESSES TODAY HOWEVER PRECIP/CLOUDS MAY OFFSET THE WARMING A
LITTLE. H5 HEIGHTS WILL BE DROPPING THURSDAY YIELDING A SLIGHTLY
COOLER TEMPS. STAYING CLOSE TO CURRENT FORECAST TEMPS AS THEY STILL
LOOKS GOOD.
01
LONG TERM /FRIDAY THROUGH WEDNESDAY/...
NO SIG CHANGES TO THE EXTENDED. ONLY CHANGE WERE TO THE POPS ON
SUNDAY WHERE OUR NEIGHBORS AND GUIDANCE SUGGESTS A LIKELY CHANCE
OF POPS. DECIDED TO GO WITH THAT FOR SUNDAY AFTERNOON. OTHERWISE
UPDATED THE DEWPOINTS...WINDS AND TEMPERATURES WITH NEW GUIDANCE.
HAVE ATTACHED PREVIOUS DISCUSSION FOR BREVITY.
ARG
LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
/ISSUED AT 355 AM EDT WED JUL 17 2013/
A TRANSITION TAKES PLACE THIS PERIOD FROM EAST FLOW ALOFT TO
WESTERLY FLOW WITH A UPPER TROUGH DEVELOPING OVER THE EASTERN
STATES. GFS AND EUROPEAN ARE SIMILAR WITH THIS CHANGE UNTIL THE
MONDAY TO WEDNESDAY TIME FRAME WHEN THE EUROPEAN MOVES THE TROUGH
TO THE WESTERN ATLANTIC AND THE GFS KEEPS THE UPPER TROUGH OVER THE
OH/TN VALLEYS AS A STRONGER UPPER SHORT WAVE MOVES OVER THE MID U.S.
PLENTY OF MOISTURE AND INSTABILITY THIS PERIOD FOR AT LEAST
SCATTERED SHOWERS AND THUNDERSTORMS FOR MOST AREAS...TENDING TO
MAXIMIZE IN THE AFTERNOON AND EVENING HOURS. DEEPER MOISTURE MOVES
ACROSS THE AREA WITH THE INITIAL ONSET OF THE UPPER TROUGH
SUNDAY/MONDAY AS A FRONT BECOMES STATIONARY JUST N OF GA AND A
SURFACE TROUGH SETS UP FROM THE CAROLINAS INTO GA. TEMPERATURES
GENERALLY CLOSE TO NORMAL EXCEPT HIGH TEMPERATURES WILL RUN
SLIGHTLY BELOW NORMAL FROM SATURDAY ON.
BDL
&&
.AVIATION...
06Z UPDATE...
RAINFALL SLOWLY ENDING WITH MOST SITES PRECIP FREE. SKIES ARE
CLEARING AND EXPECT SOME MVFR CLOUDS...MOSTLY FEW TO SCT ALONG WITH
AREAS OF FOG. EXPECT ISOLATED TO SCATTERED CONVECTION TO DEVELOP
AFTER 18Z BUT DO NOT EXPECT IT TO BE AS EXTENSIVE AS WEDNESDAY AND
WILL MAINTAIN A PROB30 TSRA THIS AFTERNOON. WINDS WILL REMAIN A
LIGHT SOUTHEAST TODAY WITH CALM OR NEAR CALM EARLY THIS MORNING AND
AGAIN TONIGHT.
//ATL CONFIDENCE...06Z UPDATE...
MODERATE ON CIG AND VSBY EARLY THIS MORNING.
HIGH ON ALL REMAINING ELEMENTS.
17
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 71 92 71 90 / 40 30 30 40
ATLANTA 74 91 73 88 / 40 30 30 50
BLAIRSVILLE 69 88 68 84 / 40 50 30 50
CARTERSVILLE 70 91 71 89 / 40 40 30 50
COLUMBUS 73 94 73 90 / 20 30 30 50
GAINESVILLE 73 90 73 88 / 40 40 30 50
MACON 71 92 71 90 / 30 30 20 40
ROME 71 92 71 90 / 40 40 30 50
PEACHTREE CITY 71 91 70 89 / 40 30 30 50
VIDALIA 72 93 72 89 / 20 30 20 40
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...01
LONG TERM....ARG
AVIATION...37
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
741 PM CDT FRI JUL 19 2013
.MESOSCALE DISCUSSION...740 PM...
SCATTERED STORMS CONTINUE TO SHOW AN UPTICK IN INTENSITY AND
COVERAGE ACROSS FAR NORTHERN ILLINOIS BACK WSW TO THE QUAD
CITIES. MUCH OF THIS CONVECTION IS ON A PRE-FRONTAL CONVERGENCE
AREA ABOUT 50-75 MILES AHEAD OF THE COOL FRONT. THIS CONVERGENT
ZONE CERTAINLY NOW LOOKS TO BE THE PRIMARY FOCUS WITH STORM
OUTFLOWS THEN DRIVING NEW DEVELOPMENT. RADAR BEHAVIOR OF THE
STORMS ON DVN AND OUR RADAR INDICATE THEY OUR SWEEPING OUTFLOWS
OUT QUICKLY FROM THEM.
THE 00Z DVN RAOB INDICATED 3300 J/KG WITH STEEP LOW-LEVEL LAPSE
RATES AND A GENERALLY HIGH LCL OF 5300 FT. NEARBY OBSERVATIONS
ALSO INDICATE CLOUDS BASES NEAR 6000 FT. RAP ANALYZED DOWNDRAFT
CAPE IS A VERY HIGH 1200-1700 J/KG. THIS ALL FAVORS MICROBURST
POTENTIAL WITH THE ISOLATED STRONGEST STORMS...ESPECIALLY WITH
DEEP WARM CLOUD LAYERS. EVEN SOME OF THE OUTFLOWS THEMSELVES COULD
HAVE GUSTINESS IN EXCESS OF 40 MPH A WAYS /20+ MILES/ FROM THE
STORM CORES THROUGH JUST QUICK PROPAGATION IN THIS TYPE OF
ENVIRONMENT. BUT AGAIN COVERAGE ON THESE STRONGER DOWNDRAFTS IS
LIKELY TO BE ISOLATED. THE HIGH WET BULB ZERO HEIGHT OF 12400 FT
ON THE DVN RAOB CONTINUES TO INDICATE HAIL IS OF A LOW THREAT AND
IT TOOK A VERY LARGE CORE TO GET JUST PENNY SIZE IN THE DVN CWA
THUS FAR. INDIVIDUAL CORE MOTIONS AT THEIR FIRST DEVELOPMENT ARE
VERY SLOW AND WOULD BE WHERE THE HEAVIEST RAIN IS MOST
FAVORED...THOUGH LOCALLY HEAVY RATES ARE LIKELY UNDER ANY STORMS
THIS EVE.
GIVEN THE ENVIRONMENT THE STORMS ARE LIKELY TO CONTINUE TO
MAINTAIN THEIR INTENSITY AND COVERAGE THROUGH 9-10 PM BUT THEN MAY
SHOW A DIMINISHING AS BOUNDARY LAYER WINDS DECREASE AND OVERALL
CONVERGENCE EASES INTO THE EVE. ALSO SURFACE-BASED LIFTING OF
PARCELS OFF OF OUTFLOWS MAY REQUIRE MORE AND MORE LATER INTO THE
EVE AND EARLY OVERNIGHT. CONVECTIVE ALLOWING MODELS...WHILE
GENERALLY HAVING STRUGGLED MUCH OF TODAY WITH TOO MUCH ACTIVITY
/POSSIBLY DUE TO THE HIGH CAPE/...HAVE GENERALLY AGREED FOR SEVERAL
RUNS THAT A DIMINISHING TREND WOULD OCCUR LATE IN THE EVE INTO
OVERNIGHT.
TIMING WOULD FAVOR THESE NEARBY OR INTO THE DOWNTOWN CHICAGO AREA
BY 930-1030 PM TAKING INTO ACCOUNT SOME POSSIBLE QUICKER
PROPAGATION AND POSSIBLE DEVELOPMENT ON OUTFLOWS. SOME GUSTINESS
IS FAVORED UNDER AND NEAR STORMS. IT WOULD APPEAR THAT BY MIDNIGHT
THE STORMS...AT LEAST WHAT IS LEFT OF THEM...WOULD HAVE EVOLVED
ESE.
MTF
&&
.DISCUSSION...
316 PM CDT
THE MAIN FORECAST CONCERNS WILL FIRST FOCUS ON CONVECTIVE TRENDS
THIS EVENING AND OVERNIGHT...AND ALSO THE HEAT THROUGH THIS EVENING.
HOWEVER...OTHER CONCERNS IN THE FORECAST PERIOD WILL BE ADDITIONAL
THREATS OF CONVECTION/MCS`S LATER THIS WEEKEND INTO EARLY NEXT WEEK.
A COLD FRONTAL BOUNDARY IS CURRENTLY DROPPING SOUTHWARD ACROSS
SOUTHERN WISCONSIN. LOW LEVEL CONVERGENCE ALONG THIS BOUNDARY HAS
REMAINED FAIRLY WEAK AS A WELL MIXED WARM SECTOR HAS PRODUCED
SOUTHWESTERLY FLOW RELATIVELY PARALLEL WITH THE SURFACE FRONT. AS A
RESULT OF THIS...STORM DEVELOPMENT HAS REMAINED ISOLATED THUS FAR.
IN SPITE OF THIS ADDITIONAL STORMS ARE STILL EXPECTED TO DEVELOP
THROUGH THE AFTERNOON. FOR MORE INFO ON THESE STORMS REFERENCE THE
MESO DISCUSSION ABOVE.
THUNDERSTORMS WILL LIKELY BECOME HIGHER IN AERIAL COVERAGE EARLY
THIS EVENING AS LOWER LEVEL MOISTURE CONVERGENCE INCREASES AHEAD THIS
BOUNDARY. IT APPEARS THE FRONT WILL BE SLOW TO CLEAR NORTHERN
ILLINOIS...POSSIBLY NOT PASSING SOUTH OF CHICAGO UNTIL AFTER 03 UTC
THIS EVENING. THEREFORE...THUNDERSTORMS WILL BE POSSIBLY THROUGH AT
LEAST EARLY TO MID EVENING ACROSS MUCH OF ILLINOIS. THERE WILL STILL
BE A THREAT FOR STORMS TO PRODUCE MICROBURSTS WITH ISOLATED AREAS OF
STRONG DAMAGING WINDS INTO THIS EVENING AS DOWNDRAFT CAPE WILL
REMAIN IN EXCESS OF 1,000 J/KG. HOWEVER...THE OTHER THREAT WILL BE
TORRENTIAL DOWNPOURS WITH THESE THUNDERSTORMS. THE RICH THETA-E
AIR...WITH PWATS UP AROUND 2 INCHES WILL PROVIDE AMPLE CONDITIONS
FOR VERY HEAVY RAINFALL FROM THESE STORMS. MY CONCERN IS THAT AS THE
LOWER LEVEL CONVERGENCE INCREASES ALONG THE LOWER LEVEL FRONTAL
ZONE...THAT SOME OF THESE STORMS COULD TRAIN...WITH A NEARLY
EASTERLY CLOUD BEARING FLOW AROUND 25 KT EXPECTED...WHICH SHOULD BE
NEARLY PARALLEL TO THE BOUNDARY. IT APPEARS THE MAIN THREAT FOR THIS
WILL BE PRIMARILY SOUTH OF CHICAGO ACROSS MY EAST CENTRAL ILLINOIS
AND NORTHWESTERN ILLINOIS COUNTIES. I HAVE MAINTAINED THE HEAVY RAIN
WORDING IN THESE AREAS...ESPECIALLY THIS EVENING. THESE STORMS COULD
EASY DROP 1 TO 2 INCHES PER HOUR...AND IF THE STORMS TRAIN OVER THE
SAME AREAS THERE COULD BE SOME LOCALIZED AREAS OF HIGH RAINFALL
AMOUNTS. THIS WILL NEED TO BE WATCHED THIS EVENING. CONFIDENCE IN
WIDESPREAD HYDRO CONCERNS IN LOW...THEREFORE NO HEADLINES ARE
PLANNED.
THE THREAT FOR THUNDERSTORMS WITH HEAVY RAIN COULD CONTINUE
OVERNIGHT ACROSS MY FAR SOUTHERN COUNTIES AS IT APPEARS THE FRONTAL
BOUNDARY WILL BE SLOW TO MOVE ACROSS THESE AREAS. HOWEVER...IT
APPEARS THAT THE FRONT SHOULD CLEAR THE AREA BY EARLY SATURDAY
MORNING...ENDING THE THREAT FOR STORMS.
I WILL LEAVE THE HEAT HEADLINES AS IS...WITH AN ENDING TIME AT 00
UTC THIS EVENING. WITH THE DEW POINTS MIXING OUT INTO THE UPPER 60S
THE HEAT INDEX HAS NOT BEEN MUCH ABOVE 100. SO ALTHOUGH THE FRONT
WILL NOT MOVE THROUGH TILL TONIGHT...IT APPEARS THE BIG HEAT WILL BE
OVER BY 00 UTC...WITH COOLER AND LESS HUMID AIR TO MOVE IN LATER
TONIGHT.
SATURDAY AND SUNDAY WILL BE COOLER...WITH HIGHS MAINLY IN THE LOW TO
MID 80S...WITH AN ONSHORE FLOW. DRY CONDITIONS ARE EXPECTED FOR MUCH
OF THE WEEKEND. HOWEVER...THE CHANCE FOR MORE STORMS WILL INCREASE
LATE SUNDAY AND SUNDAY NIGHT AS ANOTHER DISTURBANCE APPROACHES THE
AREA. IT CURRENTLY APPEARS THE MAIN FOCUS MAY BE ACROSS THE SOUTHERN
HALF TO TWO THIRDS OF MY AREA...BUT THE POTENTIAL FOR SOME
ADDITIONAL HEAVY RAIN AREA POSSIBLE INTO EARLY MONDAY.
SUBSIDENCE IN THE WAKE OF THIS DISTURBANCE MAY LEAD TO LITTLE TO NO
CONVECTIVE ACTIVITY MONDAY AFTERNOON AND NIGHT. I HAVE THEREFORE
TRENDED POPS DOWN SIGNIFICANTLY FOR THIS TIMEFRAME. HOWEVER...A
FAIRLY DISTURBED WEST-NORTHWESTERLY FLOW ALOFT OVER THE CENTRAL
CONUS WILL LIKELY DRIVE ANOTHER DISTURBANCE OR TWO ACROSS THE AREA
ON TUESDAY. THIS WILL PRODUCE ANOTHER DECENT CHANCE OF THUNDERSTORMS
TUESDAY INTO TUESDAY EVENING.
ONCE THIS DISTURBANCE MOVES THROUGH...THE FLOW ALOFT LOOKS TO AMPLIFY
SOME...WITH BUILDING HEIGHTS ACROSS THE WESTERN CONUS. THIS SHOULD
ALLOW A COLD FRONT AND AREA OF SURFACE HIGH PRESSURE TO SHIFT
SOUTHWARD ACROSS THE GREAT LAKES REGION. THIS SHOULD RESULT IN THE
MAIN THREAT FOR CONVECTIVE ACTIVITY SHIFTING SOUTH OF THE REGION FOR
WEDNESDAY THROUGH THURSDAY...WITH A CONTINUATION OF COOL
TEMPERATURES INTO LATER NEXT WEEK.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* ISOLD-SCT SHRA/TSRA AFFECTING THE AREA THROUGH APPROX 3/4Z.
* BRIEF IFR VSBY AND GUSTY WINDS IN AN CELL THAT PASSES OVERHEAD.
* WINDS SHIFTING NORTHWEST EARLY TONIGHT WITH COLD FRONTAL
PASSAGE.
* NORTH WINDS SATURDAY MORNING TURNING NORTHEAST.
MDB
//DISCUSSION...UPDATED 00Z...
SHRA/TSRA CONTINUE TO SLOWLY DEVELOP WITH THE LATEST DEVELOPMENT
OCCURRING NEAR THE IL/WI BORDER WHERE A NEW CU FIELD POPPED UP IN
THE LAST HOUR. ADDITIONAL SPOTTY ACTIVITY IS OCCURRING TO THE
NORTHWEST ALONG THE FRONT AND ALSO OUT TO THE WEST ACROSS EASTERN
IOWA. ALL OF THIS ACTIVITY WILL GRADUALLY MOVE EAST-SOUTHEAST OVER
THE NEXT SEVERAL HOURS. COVERAGE STILL LOOKS ISOLD-SCATTERED SO
THERE IS A CHANCE THE TERMINALS WILL NOT ALL BE DIRECTLY AFFECTED
BUT WILL STICK WITH VCTS/TEMPO TS MENTION FOR A FEW HOURS THIS
EVENING. ANY CELL WILL LIKELY BRING VERY HEAVY DOWNPOURS AND IFR
VSBY WITH THE STRONGEST ALSO BRINGING THE POTENTIAL FOR GUSTY
WINDS. OTHERWISE...WEST-SOUTHWEST WINDS WILL BE EASING THEN TURN
NORTHWEST LATE THIS EVENING/EARLY TONIGHT AS A COOL FRONT PASSES.
WINDS WILL THEN TURN NORTH SATURDAY MORNING THEN NORTHEAST BY
EARLY SATURDAY AFTERNOON. AN UPPER LEVEL TROUGH WILL BE PASSING
LATE IN THE DAY SO THERE MAY BE AN INCREASE IN VFR CLOUD COVER AS
WELL AS A ROGUE SHOWER OR TWO.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* HIGH CONFIDENCE IN TIMING OF SHRA/TSRA WINDOW.
* HIGH CONFIDENCE IN BRIEF IFR VSBY UNDER SHRA/TSRA...MEDIUM
CONFIDENCE THAT WIND GUSTS COULD ALSO OCCUR.
* HIGH CONFIDENCE IN WIND TRENDS WITH MEDIUM CONFIDENCE IN TIMING
OF CHANGES.
MDB
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...CHANCE SHRA/TSRA AFTERNOON-OVERNIGHT.
MONDAY...CHANCE SHRA/TSRA EARLY.
TUESDAY...CHANCE SHRA/TSRA.
WEDNESDAY AND THURSDAY...VFR.
MDB
&&
.MARINE...
329 PM CDT
INITIAL CONCERN IN THE NEARSHORE WITH GUSTY WEST-SOUTHWEST WINDS
OCCASIONALLY TO 30 KT AHEAD OF A COLD FRONT. WITH SLOW PROGRESS OF
FRONT...IT IS POSSIBLE SMALL CRAFT ADVISORY MAY NEED TO BE EXTENDED
FOR A FEW HOURS INTO MID EVENING. ALSO A FEW GUSTY STORMS ARE
POSSIBLE THROUGH EARLY EVENING...WITH AN OUTSIDE CHANCE FOR GUSTS
OVER 50 KT. THIS INCLUDES THE OPEN WATERS.
BEHIND THE FRONT...A STRONG PUSH OF COOL AIR FOR THIS TIME OF YEAR
WILL MOVE DOWN THE LAKE RESULTING IN INCREASING NORTHERLY
WINDS...FIRST ON THE NORTH HALF SHIFTING TO THE SOUTH HALF DURING
THE DAY SATURDAY. THERE MAY BE OCCASIONAL GUSTS TO 30 KT OVER THE
OPEN WATERS. THEN HIGH PRESSURE WILL BUILD OVER THE LAKE BY SUNDAY
AND WINDS WILL DIMINISH. THOUGH LOW PRESSURE WILL MOVE OVER THE
REGION EARLY NEXT WEEK AND A COLD FRONT WILL PUSH ACROSS THE LAKE
BY TUESDAY...WINDS LOOK TO REMAIN FAIRLY LIGHT OUT OF THE SOUTH
UNTIL THE COLD FRONT PASSAGE. THEN AFTER THE FRONTAL PASSAGE LATE
TUESDAY...THERE COULD POTENTIALLY BE A PERIOD OF MODESTLY STRONGER
NORTHERLY WINDS FOLLOWED BY AN EXTENDED PERIOD OF LIGHT WINDS MID
TO LATE NEXT WEEK AS HIGH PRESSURE SPREADS ACROSS THE GREAT LAKES.
RC
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
648 PM CDT FRI JUL 19 2013
.MESOSCALE DISCUSSION...
ISOLATED CONVECTION IS DEVELOPING ALONG THE COOL FRONT AND A
SUBTLE PRE-FRONTAL WIND CONVERGENCE FROM CENTRAL WI INTO
SOUTHEAST IA LATE THIS AFTERNOON. THIS NOW LOOKS TO BE THE ONLY
FOCUS FOR STORM ACTIVITY WITH THE REST OF THE CU HAVING
DISSIPATED ACROSS THE REGION.
THE COOL FRONT IS WELL-DEFINED ON OBSERVATIONS AND SATELLITE AND
EASING ITS WAY SOUTHEAST AT 15 KT. WATER VAPOR AND PROFILERS
INDICATE GRADUALLY INCREASE UPPER TO MID-LEVEL FLOW IS SETTLING
SOUTH ACROSS THE UPPER MISSISSIPPI VALLEY ASSOCIATED WITH THE
UPPER TROUGH. THIS MAY BE PROVIDING SOME BROAD ASCENT TO HELP
CONVECTION TO DEVELOP AS WELL.
THE MAIN PRESSURE RISES AND MOMENTUM BEHIND THE FRONT IS SHIFTING
MORE EAST THAN SOUTH ACROSS WI AND THUS IT CONTINUES TO BE
CONCERNING JUST HOW SHARP CONVERGENCE WILL OR WILL NOT BE THROUGH
THE EVENING AS THE FRONT APPROACHES AND MOVES INTO THE FORECAST
AREA. ALSO...THE FRONT IS NOW GOING AGAINST THE DIURNAL GRAIN AND
MOST OF THE LOW-LEVEL JET AND MOISTURE TRANSPORT FOCUS IS TO THE
NORTHEAST OF THE FORECAST AREA. SO THIS POINTS TOWARD SCATTERED
CONVECTION ONLY...MAYBE AT BEST...WITH THE FRONTAL PASSAGE. ANY
STORMS THAT DEVELOP WILL STILL HAVE PLENTY OF INSTABILITY WITH
SFC BASED CAPE ON RAP AND LAPS OF 2000 TO 3000 J/KG AND ASSOCIATED
LARGE VALUES OF DOWNDRAFT CAPE. THUS STORMS COULD FESTER/DEVELOP
ON OUTFLOWS AHEAD OF THE FRONT IF ANY CAN SUSTAIN THEMSELVES. EVEN
WITH THAT THOUGH...THINK COVERAGE WILL BE LIMITED AND MORE SO THAN
WHAT SEVERAL CONVECTIVE ALLOWING MODELS ARE SHOWING. CONVECTION
COULD CONCEIVABLY COME UP THE NEXT COUPLE HOURS AND THEN WANE AS
IT MOVES INTO THE FORECAST AREA.
POPS HAVE BEEN ADJUSTED AND LOWERED SOME TO ACCOUNT FOR LESS
COVERAGE WITH THE FRONT.
MTF
&&
.DISCUSSION...
316 PM CDT
THE MAIN FORECAST CONCERNS WILL FIRST FOCUS ON CONVECTIVE TRENDS
THIS EVENING AND OVERNIGHT...AND ALSO THE HEAT THROUGH THIS EVENING.
HOWEVER...OTHER CONCERNS IN THE FORECAST PERIOD WILL BE ADDITIONAL
THREATS OF CONVECTION/MCS`S LATER THIS WEEKEND INTO EARLY NEXT WEEK.
A COLD FRONTAL BOUNDARY IS CURRENTLY DROPPING SOUTHWARD ACROSS
SOUTHERN WISCONSIN. LOW LEVEL CONVERGENCE ALONG THIS BOUNDARY HAS
REMAINED FAIRLY WEAK AS A WELL MIXED WARM SECTOR HAS PRODUCED
SOUTHWESTERLY FLOW RELATIVELY PARALLEL WITH THE SURFACE FRONT. AS A
RESULT OF THIS...STORM DEVELOPMENT HAS REMAINED ISOLATED THUS FAR.
IN SPITE OF THIS ADDITIONAL STORMS ARE STILL EXPECTED TO DEVELOP
THROUGH THE AFTERNOON. FOR MORE INFO ON THESE STORMS REFERENCE THE
MESO DISCUSSION ABOVE.
THUNDERSTORMS WILL LIKELY BECOME HIGHER IN AERIAL COVERAGE EARLY
THIS EVENING AS LOWER LEVEL MOISTURE CONVERGENCE INCREASES AHEAD THIS
BOUNDARY. IT APPEARS THE FRONT WILL BE SLOW TO CLEAR NORTHERN
ILLINOIS...POSSIBLY NOT PASSING SOUTH OF CHICAGO UNTIL AFTER 03 UTC
THIS EVENING. THEREFORE...THUNDERSTORMS WILL BE POSSIBLY THROUGH AT
LEAST EARLY TO MID EVENING ACROSS MUCH OF ILLINOIS. THERE WILL STILL
BE A THREAT FOR STORMS TO PRODUCE MICROBURSTS WITH ISOLATED AREAS OF
STRONG DAMAGING WINDS INTO THIS EVENING AS DOWNDRAFT CAPE WILL
REMAIN IN EXCESS OF 1,000 J/KG. HOWEVER...THE OTHER THREAT WILL BE
TORRENTIAL DOWNPOURS WITH THESE THUNDERSTORMS. THE RICH THETA-E
AIR...WITH PWATS UP AROUND 2 INCHES WILL PROVIDE AMPLE CONDITIONS
FOR VERY HEAVY RAINFALL FROM THESE STORMS. MY CONCERN IS THAT AS THE
LOWER LEVEL CONVERGENCE INCREASES ALONG THE LOWER LEVEL FRONTAL
ZONE...THAT SOME OF THESE STORMS COULD TRAIN...WITH A NEARLY
EASTERLY CLOUD BEARING FLOW AROUND 25 KT EXPECTED...WHICH SHOULD BE
NEARLY PARALLEL TO THE BOUNDARY. IT APPEARS THE MAIN THREAT FOR THIS
WILL BE PRIMARILY SOUTH OF CHICAGO ACROSS MY EAST CENTRAL ILLINOIS
AND NORTHWESTERN ILLINOIS COUNTIES. I HAVE MAINTAINED THE HEAVY RAIN
WORDING IN THESE AREAS...ESPECIALLY THIS EVENING. THESE STORMS COULD
EASY DROP 1 TO 2 INCHES PER HOUR...AND IF THE STORMS TRAIN OVER THE
SAME AREAS THERE COULD BE SOME LOCALIZED AREAS OF HIGH RAINFALL
AMOUNTS. THIS WILL NEED TO BE WATCHED THIS EVENING. CONFIDENCE IN
WIDESPREAD HYDRO CONCERNS IN LOW...THEREFORE NO HEADLINES ARE
PLANNED.
THE THREAT FOR THUNDERSTORMS WITH HEAVY RAIN COULD CONTINUE
OVERNIGHT ACROSS MY FAR SOUTHERN COUNTIES AS IT APPEARS THE FRONTAL
BOUNDARY WILL BE SLOW TO MOVE ACROSS THESE AREAS. HOWEVER...IT
APPEARS THAT THE FRONT SHOULD CLEAR THE AREA BY EARLY SATURDAY
MORNING...ENDING THE THREAT FOR STORMS.
I WILL LEAVE THE HEAT HEADLINES AS IS...WITH AN ENDING TIME AT 00
UTC THIS EVENING. WITH THE DEW POINTS MIXING OUT INTO THE UPPER 60S
THE HEAT INDEX HAS NOT BEEN MUCH ABOVE 100. SO ALTHOUGH THE FRONT
WILL NOT MOVE THROUGH TILL TONIGHT...IT APPEARS THE BIG HEAT WILL BE
OVER BY 00 UTC...WITH COOLER AND LESS HUMID AIR TO MOVE IN LATER
TONIGHT.
SATURDAY AND SUNDAY WILL BE COOLER...WITH HIGHS MAINLY IN THE LOW TO
MID 80S...WITH AN ONSHORE FLOW. DRY CONDITIONS ARE EXPECTED FOR MUCH
OF THE WEEKEND. HOWEVER...THE CHANCE FOR MORE STORMS WILL INCREASE
LATE SUNDAY AND SUNDAY NIGHT AS ANOTHER DISTURBANCE APPROACHES THE
AREA. IT CURRENTLY APPEARS THE MAIN FOCUS MAY BE ACROSS THE SOUTHERN
HALF TO TWO THIRDS OF MY AREA...BUT THE POTENTIAL FOR SOME
ADDITIONAL HEAVY RAIN AREA POSSIBLE INTO EARLY MONDAY.
SUBSIDENCE IN THE WAKE OF THIS DISTURBANCE MAY LEAD TO LITTLE TO NO
CONVECTIVE ACTIVITY MONDAY AFTERNOON AND NIGHT. I HAVE THEREFORE
TRENDED POPS DOWN SIGNIFICANTLY FOR THIS TIMEFRAME. HOWEVER...A
FAIRLY DISTURBED WEST-NORTHWESTERLY FLOW ALOFT OVER THE CENTRAL
CONUS WILL LIKELY DRIVE ANOTHER DISTURBANCE OR TWO ACROSS THE AREA
ON TUESDAY. THIS WILL PRODUCE ANOTHER DECENT CHANCE OF THUNDERSTORMS
TUESDAY INTO TUESDAY EVENING.
ONCE THIS DISTURBANCE MOVES THROUGH...THE FLOW ALOFT LOOKS TO AMPLIFY
SOME...WITH BUILDING HEIGHTS ACROSS THE WESTERN CONUS. THIS SHOULD
ALLOW A COLD FRONT AND AREA OF SURFACE HIGH PRESSURE TO SHIFT
SOUTHWARD ACROSS THE GREAT LAKES REGION. THIS SHOULD RESULT IN THE
MAIN THREAT FOR CONVECTIVE ACTIVITY SHIFTING SOUTH OF THE REGION FOR
WEDNESDAY THROUGH THURSDAY...WITH A CONTINUATION OF COOL
TEMPERATURES INTO LATER NEXT WEEK.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* ISOLD-SCT SHRA/TSRA AFFECTING THE AREA THROUGH APPROX 3/4Z.
* BRIEF IFR VSBY AND GUSTY WINDS IN AN CELL THAT PASSES OVERHEAD.
* WINDS SHIFTING NORTHWEST EARLY TONIGHT WITH COLD FRONTAL
PASSAGE.
* NORTH WINDS SATURDAY MORNING TURNING NORTHEAST.
MDB
//DISCUSSION...UPDATED 00Z...
SHRA/TSRA CONTINUE TO SLOWLY DEVELOP WITH THE LATEST DEVELOPMENT
OCCURRING NEAR THE IL/WI BORDER WHERE A NEW CU FIELD POPPED UP IN
THE LAST HOUR. ADDITIONAL SPOTTY ACTIVITY IS OCCURRING TO THE
NORTHWEST ALONG THE FRONT AND ALSO OUT TO THE WEST ACROSS EASTERN
IOWA. ALL OF THIS ACTIVITY WILL GRADUALLY MOVE EAST-SOUTHEAST OVER
THE NEXT SEVERAL HOURS. COVERAGE STILL LOOKS ISOLD-SCATTERED SO
THERE IS A CHANCE THE TERMINALS WILL NOT ALL BE DIRECTLY AFFECTED
BUT WILL STICK WITH VCTS/TEMPO TS MENTION FOR A FEW HOURS THIS
EVENING. ANY CELL WILL LIKELY BRING VERY HEAVY DOWNPOURS AND IFR
VSBY WITH THE STRONGEST ALSO BRINGING THE POTENTIAL FOR GUSTY
WINDS. OTHERWISE...WEST-SOUTHWEST WINDS WILL BE EASING THEN TURN
NORTHWEST LATE THIS EVENING/EARLY TONIGHT AS A COOL FRONT PASSES.
WINDS WILL THEN TURN NORTH SATURDAY MORNING THEN NORTHEAST BY
EARLY SATURDAY AFTERNOON. AN UPPER LEVEL TROUGH WILL BE PASSING
LATE IN THE DAY SO THERE MAY BE AN INCREASE IN VFR CLOUD COVER AS
WELL AS A ROGUE SHOWER OR TWO.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* HIGH CONFIDENCE IN TIMING OF SHRA/TSRA WINDOW.
* HIGH CONFIDENCE IN BRIEF IFR VSBY UNDER SHRA/TSRA...MEDIUM
CONFIDENCE THAT WIND GUSTS COULD ALSO OCCUR.
* HIGH CONFIDENCE IN WIND TRENDS WITH MEDIUM CONFIDENCE IN TIMING
OF CHANGES.
MDB
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...CHANCE SHRA/TSRA AFTERNOON-OVERNIGHT.
MONDAY...CHANCE SHRA/TSRA EARLY.
TUESDAY...CHANCE SHRA/TSRA.
WEDNESDAY AND THURSDAY...VFR.
MDB
&&
.MARINE...
329 PM CDT
INITIAL CONCERN IN THE NEARSHORE WITH GUSTY WEST-SOUTHWEST WINDS
OCCASIONALLY TO 30 KT AHEAD OF A COLD FRONT. WITH SLOW PROGRESS OF
FRONT...IT IS POSSIBLE SMALL CRAFT ADVISORY MAY NEED TO BE EXTENDED
FOR A FEW HOURS INTO MID EVENING. ALSO A FEW GUSTY STORMS ARE
POSSIBLE THROUGH EARLY EVENING...WITH AN OUTSIDE CHANCE FOR GUSTS
OVER 50 KT. THIS INCLUDES THE OPEN WATERS.
BEHIND THE FRONT...A STRONG PUSH OF COOL AIR FOR THIS TIME OF YEAR
WILL MOVE DOWN THE LAKE RESULTING IN INCREASING NORTHERLY
WINDS...FIRST ON THE NORTH HALF SHIFTING TO THE SOUTH HALF DURING
THE DAY SATURDAY. THERE MAY BE OCCASIONAL GUSTS TO 30 KT OVER THE
OPEN WATERS. THEN HIGH PRESSURE WILL BUILD OVER THE LAKE BY SUNDAY
AND WINDS WILL DIMINISH. THOUGH LOW PRESSURE WILL MOVE OVER THE
REGION EARLY NEXT WEEK AND A COLD FRONT WILL PUSH ACROSS THE LAKE
BY TUESDAY...WINDS LOOK TO REMAIN FAIRLY LIGHT OUT OF THE SOUTH
UNTIL THE COLD FRONT PASSAGE. THEN AFTER THE FRONTAL PASSAGE LATE
TUESDAY...THERE COULD POTENTIALLY BE A PERIOD OF MODESTLY STRONGER
NORTHERLY WINDS FOLLOWED BY AN EXTENDED PERIOD OF LIGHT WINDS MID
TO LATE NEXT WEEK AS HIGH PRESSURE SPREADS ACROSS THE GREAT LAKES.
RC
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...HEAT ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-
ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-
ILZ032-ILZ033-ILZ039 UNTIL 7 PM FRIDAY.
IN...HEAT ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 7 PM
FRIDAY.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 7 PM FRIDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS LINCOLN IL
334 AM CDT THU JUL 18 2013
.DISCUSSION...
ISSUED 330 AM CDT THU JUL 18 2013
SHORT TERM...TODAY THROUGH SUNDAY
STRONG 598 DM 500 MB HIGH PRESSURE RIDGE FROM MO AND CENTRAL IL
INTO THE OHIO VALLEY WILL CONTINUE THE HEAT WAVE ACROSS IL
THROUGH FRIDAY WITH HOT AND HUMID CONDITIONS. HEAT INDICES GRADUALLY
GETTING HIGHER EACH DAY DURING THIS WORK WEEK. HEAT INDICES THAT
REACHED 97-102F YESTERDAY AFTERNOON WILL REACH 99-104F THIS
AFTERNOON AND 101-106F FRIDAY AFTERNOON. WILL ISSUE SPECIAL
WEATHER STATEMENT TO ADDRESS THIS HEAT WAVE AND A HEAT ADIVSORY
MAY EVENTUALLY BE NEEDED FRIDAY AFTERNOON WHICH APPEARS TO BE THE
HOTTEST DAY OVER CENTRAL IL WITH HIGHS IN THE 90S. 850 MB TEMPS
ELEVATE TO 19-20C THIS AFTERNOON AND NW AREAS PEAK FROM 20-22C FRI
AFTERNOON AND SUPPORTS EVENT HOTTER CONDITIONS FRIDAY.
SOME SHORT WAVE ENERGY OVER THE TN VALLEY WILL DRIFT WESTWARD
DURING TODAY AND COULD BRING ISOLATED CONVECTION TO FAR SE IL LATE
THIS AFTERNOON/EARLY EVENING AND ADDED 20% POPS FROM ROBINSON TO
LOUSIVILLE SOUTH. LESS THAN 10% CHANCE OF A SHOWER OR THUNDERSTORM
IN TROPICAL AIR MASS FROM 3-7 PM OVER CENTRAL IL SIMILAR TO
YESTERDAY WHEN BLOOMINGTON AIRPORT PICKED UP 1 INCH OF RAIN IN A
HALF HOUR FROM 415-445 PM. SCATTERED CUMULUS CLOUDS DEVELOP LATE
MORNING AND AFTERNOON WITH PARTLY TO MOSTLY SUNNY SKIES. THESE
CUMULUS CLOUDS DISSIPATE AT SUNDOWN LEAVING FAIR SKIES AGAIN
TONIGHT. HIGHS THIS AFTERNOON 90-95F WITH LOWS TONIGHT IN LOW TO
MID 70S. HIGHS FRIDAY AFTERNOON GENERALLY IN THE MID 90S WITH A
FEW UPPER 90S POSSIBLE NW OF THE IL RIVER WHERE 925-850 MB TEMPS
HIGHEST WITH COMPRESSIONAL HEATING AHEAD OF COLD FRONT SINKING
SOUTHWARD TOWARD NORTHERN IL FROM WI.
MODELS HAVE TRENDED SLOWER WITH COLD FRONT MOVING SOUTHWARD
THROUGH CENTRAL IL FRIDAY NIGHT/SAT AND HAVE TRENDED WX/POPS IN
THAT DIRECTION. JUST SLIGHT CHANCE OF CONVECTION FRI AFTERNOON
MAINLY LATE FROM PEORIA NORTH AND NEAR THE WABASH RIVER VALLEY.
BRING BETTER CHANCES OF CONVECTION INTO CENTRAL IL FRI NIGHT AND
BEST CHANCES SHIFT INTO SE IL DURING SAT. SPC HAS SLIGHT RISK OF
SEVERE STORMS NE OF A PEORIA TO DANVILLE LINE FRI NIGHT AND ACROSS
EASTERN IL SAT. LINGERED A 20-30% CHANCE OF CONVECTION SE OF I-70
SAT EVENING THEN DRY CONDITIONS EXPECTED REST OF SAT NIGHT INTO
SUNDAY. HIGHS IN THE MID TO UPPER 80S SAT WITH SE IL AROUND 90F
COOL INTO THE LOW TO MID 80S FOR HIGHS SUNDAY AS DEWPOINTS LOWER.
LONG TERM...SUNDAY NIGHT THROUGH WEDNESDAY
IL ENTRENCHED IN A WNW UPPER LEVEL FLOW DURING FIRST HALF OF NEXT
WEEK WITH A COUPLE DISTURBANCES AND POSSIBLE MCS TO TRACK ESE
THROUGH THE MIDWEST DURING THIS TIME. ONE APPEARS TO MOVE THROUGH
SUNDAY NIGHT/MONDAY AND ANOTHER ONE TUE NIGHT/WED. INCREASING
HUMIDITY DURING THIS TIME AS WELL WITH DEWPOINTS RISING BACK INTO
THE LOW TO MID 70S. ANY OUTFLOW BOUNDARY FROM THESE MCS COULD
DEVELOP ISOLATED/SCATTERED CONVECTION EACH AFTERNOON/EVENING.
HIGHS IN THE LOW TO MID 80S MONDAY AND MID TO UPPER 80S TUE/WED.
LOWS IN THE UPPER 60S AND LOWER 70S EXPECTED DURING THIS TIME FRAME.
07
&&
.AVIATION...
ISSUED 1135 PM CDT WED JUL 17 2013
MAIN CONCERN REMAINS WITH MVFR CONDITIONS WITH LIGHT FOG
OVERNIGHT. HAVE BEEN SEEING VISIBILITIES LOWERING TO AROUND 7SM
ALREADY NEAR THE INDIANA BORDER AND CREEPING NORTHWEST...AND WINDS
ARE BASICALLY CALM. KBMI IS THE ONLY ONE THAT HAS SEEN DECENT
RAINFALL OVER THE LAST COUPLE DAYS WHICH WILL ADD MOISTURE TO THE
AIR...AND STILL THINK THEY WILL BE THE MOST LIKELY TO SEE MVFR
CONDITIONS. LATEST RAP MODEL FOCUSES THE THICKEST FOG JUST SOUTH
OF KCMI/KDEC...AND WILL MAINTAIN THE TEMPO PERIODS OF LIGHT FOG.
DAYTIME HOURS ON THURSDAY WILL BE SIMILAR TO WEDNESDAY...I.E.
SCATTERED DIURNAL CLOUDS AROUND 3500 FEET DEVELOPING MID-MORNING
AND FADING OFF TOWARD SUNSET.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1136 PM CDT WED JUL 17 2013
.DISCUSSION...
ISSUED 830 PM CDT WED JUL 17 2013
LAST OF THE DIURNAL CUMULUS HAS FADED...WITH SOME HIGH CLOUDS
MOVING INTO THE FAR SOUTHEAST CWA FROM SOME CONVECTION ALONG THE
OHIO VALLEY. HIGH PRESSURE SITTING OVER CHAMPAIGN WILL KEEP WINDS
LIGHT TO CALM OVERNIGHT...WITH SKIES MAINLY CLEAR ASIDE FROM THE
CIRRUS PREVIOUSLY MENTIONED. TEMPERATURES A LITTLE SLOW TO DROP
OFF SO FAR...BUT THINK THAT LOWER 70S STILL LOOKS GOOD OVER MOST
OF THE AREA FOR LOWS TONIGHT. HAVE SENT SOME GRID UPDATES TO
REFLECT THE LATEST TRENDS...BUT NO CHANGES NEEDED TO THE WORDED
FORECASTS.
GEELHART
&&
.AVIATION...
ISSUED 1135 PM CDT WED JUL 17 2013
MAIN CONCERN REMAINS WITH MVFR CONDITIONS WITH LIGHT FOG
OVERNIGHT. HAVE BEEN SEEING VISIBILITIES LOWERING TO AROUND 7SM
ALREADY NEAR THE INDIANA BORDER AND CREEPING NORTHWEST...AND WINDS
ARE BASICALLY CALM. KBMI IS THE ONLY ONE THAT HAS SEEN DECENT
RAINFALL OVER THE LAST COUPLE DAYS WHICH WILL ADD MOISTURE TO THE
AIR...AND STILL THINK THEY WILL BE THE MOST LIKELY TO SEE MVFR
CONDITIONS. LATEST RAP MODEL FOCUSES THE THICKEST FOG JUST SOUTH
OF KCMI/KDEC...AND WILL MAINTAIN THE TEMPO PERIODS OF LIGHT FOG.
DAYTIME HOURS ON THURSDAY WILL BE SIMILAR TO WEDNESDAY...I.E.
SCATTERED DIURNAL CLOUDS AROUND 3500 FEET DEVELOPING MID-MORNING
AND FADING OFF TOWARD SUNSET.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 258 PM CDT WED JUL 17 2013
DOME OF HIGH PRESSURE BRINGING STIFLING HEAT TO ILLINOIS SHOULD
BREAK DOWN BY THE END OF THE WEEK ALLOWING A RETURN TO NORTHWEST
FLOW AND COOLER TEMPS.
SHORT TERM...TONIGHT THROUGH FRIDAY
597 DM RIDGE REMAINS ENTRENCHED OVER ILLINOIS TODAY LEADING TO
VERY WARM TEMPERATURES AND LIGHT WINDS. HEAT INDEX VALUES HAVE
TOPPED OFF NEAR 100 DEGREES AT MOST LOCATIONS AND LOOKS LIKE
SIMILAR CONDITIONS ARE LIKELY THROUGH FRIDAY. A FRONT BEGINS TO
APPROACH FROM THE NORTH ON FRIDAY AS SHORT WAVES EAT AWAY AT MID-
LEVEL RIDGE. ENOUGH RESIDUAL WARM DRY AIR ALOFT SHOULD BE IN PLACE
FRIDAY TO KEEP CAP IN PLACE PER NAM WRF. MOISTURE WILL LIKELY POOL
AHEAD OF THE BOUNDARY...BUT GFS HAS OVERESTIMATED DEW POINTS PAST
FEW DAYS AND WITH GULF MOISTURE CUTOFF LIKE DRIER NAM. INCREASE IN
POOLING BOUNDARY LAYER MOISTURE WILL LIKELY LEAD TO INCREASE IN
HEAT INDEX FOR FRIDAY. FORECAST VALUES ARE CURRENTLY BELOW HEAT
ADVISORY CRITERIA...BUT WITH MULTIPLE DAYS NEAR 100 OR ABOVE LATER
SHIFTS MAY NEED TO REVISIT ISSUING.
LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY
TRANSITION TO NORTHWEST FLOW ALOFT CONTINUES OVER THE WEEKEND AS
500 DM HEIGHT FALLS ABOUT 150 METERS BETWEEN NOW AND 00Z SUNDAY.
HEIGHT FALLS SHOULD BE SUFFICIENT TO PUSH FRONT THROUGH FORECAST AREA
LATE FRIDAY NIGHT AND SATURDAY. CONVERGENCE ALONG FRONT MAY BE
SUFFICIENT TO BREAK CAP SO WILL INCLUDE CHC POPS IN THE VICINITY
OF THE BOUNDARY. ECMWF DROPS 850 TEMPS 5-7C/24 HOURS BY SATURDAY
EVENING WHICH SHOULD BRING OUR HIGH TEMPS 10-15 DEGREES COOLER FOR
SATURDAY...PARTICULARLY WITH ANY RESIDUAL CLOUDS FOLLOWING FRONTAL
PASSAGE.
BY LATE SUNDAY NORTHWEST FLOW ALOFT IS FIRMLY ESTABLISHED AND WEAK
SHORTWAVES ARE PASSING THROUGH THE FLOW. THERE ARE INDICATIONS
THAT SEVERAL OF THESE WAVES WILL PROVIDE ENOUGH LIFT FOR POTENTIAL
CONVECTION. HOWEVER...THE MAIN QUESTION IS HOW MUCH MOISTURE WILL
BE AVAILABLE TO TAP WHICH WILL DETERMINE THE COVERAGE AND
INTENSITY OF CONVECTIVE EVENTS. TIMING IS ALSO AN ISSUE AS IT
OFTEN IS WITH WEAK SHORTWAVES MOVING THROUGH NORTHWEST FLOW. BEST
WE CAN DO AT THIS POINT IS TO INTRODUCE LOW CHC POPS SUNDAY NIGHT
AND THEN KEEP THEM GOING THROUGH THE FIRST PART OF THE WEEK.
TEMPS SHOULD REMAIN NEAR TO SLIGHTLY BELOW NORMAL WITH OCCASIONAL
PERIODS OF CLOUDS KEEPING TEMPS DOWN A BIT.
BARKER
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
239 PM EDT THU JUL 18 2013
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 346 AM EDT THU JUL 18 2013
HOT AND HUMID WEATHER WILL CONTINUE THROUGH FRIDAY AS THE RIDGE
ALOFT GRADUALLY SHIFTS TO THE SOUTH. A VIGOROUS UPPER LEVEL LOW WILL
TRACK THROUGH EASTERN CANADA WITH A COLD FRONT TRACKING SOUTH INTO
THE REGION ON SATURDAY. THE ARRIVAL AND PASSAGE OF THE FRONT WILL
BRING NUMEROUS SHOWERS AND THUNDERSTORMS TO CENTRAL INDIANA LATE
FRIDAY NIGHT THROUGH SATURDAY EVENING. COOLER DRIER AIR WILL BRIEFLY
BUILD INTO THE REGION ON SUNDAY AS HIGH PRESSURE PASSES THROUGH THE
GREAT LAKES. CHANCES FOR THUNDERSTORMS WILL RETURN BY LATE SUNDAY
NIGHT AND MONDAY AND CONTINUE THROUGH THE MIDDLE OF NEXT WEEK AS THE
FRONTAL BOUNDARY DRIFTS BACK NORTH INTO THE AREA.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1042 AM EDT THU JUL 18 2013
FEW IF ANY CHANGES NEEDED AT THIS TIME. FORECAST APPEARS TO BE IN
GOOD SHAPE. PREVIOUS DISCUSSION FOLLOWS...
ANOTHER MUGGY START EARLY THIS MORNING AS 07Z TEMPS GENERALLY IN THE
MID AND UPPER 70S. CONVECTIVE DEBRIS CLOUDS CONTINUE TO DRIFT INTO
THE SOUTHERN HALF OF THE FORECAST AREA AS A WEAK UPPER WAVE
CURRENTLY TRACKS ACROSS THE TENNESSEE VALLEY.
THE UPPER LEVEL HIGH REMAINS PARKED ACROSS CENTRAL INDIANA WITH MID
LEVEL HEIGHT MAXES STILL AROUND 597DAM. THESE HEIGHTS WILL SLOWLY
FALL THROUGH THE DAY AS THE RIDGE GRADUALLY BUCKLES IN RESPONSE TO A
DEVELOPING STRONG UPPER LOW GETTING ITS ACT TOGETHER ACROSS JAMES
BAY. THE AFOREMENTIONED WEAK WAVE ALOFT OVER THE TENNESSEE VALLEY
WILL DRIFT WEST THROUGH THE DAY AND SHOULD BE LOCATED OVER THE LOWER
OHIO VALLEY BY LATE DAY. SCATTERED CONVECTION ASSOCIATED WITH THIS
FEATURE SHOULD DEVELOP ACROSS KENTUCKY AND TENNESSEE AND MAY EVEN
SEE A FEW STORMS MAKE IT INTO OUR SOUTHERN COUNTIES. THE HRRR LOOKS
TO BE OVERDOING CONVECTIVE DEVELOPMENT IN GENERAL BUT HINTS AT THIS
IDEA AS WELL. CONSIDERING THE NATURE OF THE AIRMASS AND THE
PROXIMITY OF THE UPPER WAVE...ISOLATED POPS ARE WARRANTED ACROSS FAR
SOUTHERN COUNTIES FOR THIS AFTERNOON. FURTHER NORTH DESPITE THE
GRADUALLY LOWERING MID LEVEL HEIGHTS...THE RIDGING ALOFT AND CAP
NEAR 650MB ARE LIKELY TO REMAIN TOO STRONG FOR ANY SUBSTANTIAL
CONVECTIVE DEVELOPMENT. WHILE AN ISOLATED SHOWER CANNOT BE RULED
OUT...COVERAGE LIKELY TO BE SO LOW TO PRECLUDE ANY MENTION IN THE
FORECAST AT THIS TIME.
TEMPS...LOW LEVEL THERMALS WILL BE SIMILAR TO WEDNESDAY WITH 850MB
TEMPS RISING TO AROUND 19-20C. LIKEWISE EXPECT HIGH TEMPS TO BE
SIMILAR TO WEDNESDAY AS WELL...REACHING THE 92-94 DEGREE RANGE FOR
MUCH OF THE FORECAST AREA. GENERALLY GOING A DEGREE OR TWO ABOVE
MOS. MAX HEAT INDICES WILL RISE TO AROUND 100 DEGREES AGAIN THIS
AFTERNOON...AND MAY TOP OUT JUST A TOUCH WARMER THAN WEDNESDAY AS
SLIGHTLY DEEPER MOISTURE IS PULLED NORTH INTO THE REGION. HAVE NO
PLANS TO INTRODUCE A HEAT ADVISORY AS THESE VALUES REMAINS BELOW
CRITERIA. WILL CONTINUE WITH THE SPS.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 346 AM EDT THU JUL 18 2013
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES AND TEMPS AS A COLD
FRONT DROPS SOUTH THROUGH THE REGION SATURDAY. MODELS GENERALLY IN
VERY GOOD AGREEMENT ON MAIN FEATURES THROUGHOUT THE SHORT TERM.
RIDGING ALOFT WILL CONTINUE TO SINK SOUTH AND FLATTEN AS THE DEEP
UPPER LOW DIVES ACROSS NORTHERN ONTARIO...THEN PINWHEELS INTO THE
CANADIAN MARITIMES BY SUNDAY MORNING. ROBUST CONVECTIVE DEVELOPMENT
WILL TAKE PLACE TONIGHT OVER THE UPPER MISSISSIPPI VALLEY AND
NORTHERN GREAT LAKES IN PROXIMITY TO THE COLD FRONT. THIS FRONT WILL
SINK SOUTH AND SHOULD BE LOCATED ACROSS THE WESTERN GREAT LAKES BY
FRIDAY AFTERNOON. THE FLATTENING OF THE RIDGE AND APPROACH OF THE
COLD FRONT WILL ENCOURAGE A W/SW FLOW THROUGH THE LOWER LEVELS ON
FRIDAY...WITH POTENTIAL FOR SOME GUSTS TO NEAR 20-25KTS OVER
NORTHERN COUNTIES BY AFTERNOON AS A LOW LEVEL JET ACCOMPANIES THE
BOUNDARY THROUGH THE GREAT LAKES. WILL MAINTAIN LOW CHANCE POPS FOR
ISOLATED CONVECTIVE DEVELOPMENT FRIDAY AFTERNOON...BUT ANTICIPATE IT
WILL BE MORE FOCUSED OVER THE SOUTHERN HALF OF THE FORECAST AREA
WHERE DEEPER MOISTURE WILL RESIDE. THE W/SW FLOW WILL DRAW A SLUG OF
DRIER AIR ALOFT INTO THE LOWER GREAT LAKES IMMEDIATELY AHEAD OF THE
FRONT THAT WILL GRADUALLY BECOME SQUEEZED BY MOISTURE ADVECTING
NORTH AROUND THE BACK SIDE OF THE BERMUDA HIGH AND MOISTURE POOLING
ALONG THE BOUNDARY. THIS MAY LIMIT CONVECTIVE DEVELOPMENT OVER
NORTHERN COUNTIES FOR MUCH OF THE DAY.
FOCUS WILL SHIFT TO THE N/NW OF THE REGION BY LATE FRIDAY AFTERNOON
AS CONVECTION IS LIKELY TO DEVELOP IN THE VICINITY OF THE BOUNDARY
AND QUICKLY BECOME SEVERE AS BL SHEAR VALUES ARE ENHANCED AND
AIRMASS WILL BE MODERATELY UNSTABLE. STORMS ARE LIKELY TO ORGANIZE
INTO A MESOSCALE CONVECTIVE COMPLEX BY FRIDAY EVENING WITH
THERMODYNAMIC PROFILES SUGGESTING THE POTENTIAL FOR A SIGNIFICANT
DAMAGING WIND THREAT AS THE STORMS MOVE ACROSS THE LOWER GREAT
LAKES. THIS CONVECTION SHOULD LARGELY REMAIN TO THE NORTH OF THE
FORECAST AREA THROUGH THE EVENING...WITH PRECIP CHANCES RISING AFTER
MIDNIGHT AS THE TAIL END OF THE COMPLEX SAGS SOUTH INTO THE REGION
WITH THE COLD FRONT. AT THIS POINT...THERE IS GREATER UNCERTAINTY AS
TO THE POTENTIAL FOR CONVECTION TO MAINTAIN ITS INTENSITY OVER THE
FORECAST AREA LATE FRIDAY NIGHT. THE CORE OF THE COMPLEX IS EXPECTED
TO TRACK ACROSS THE LOWER GREAT LAKES IN CLOSER PROXIMITY TO THE
DEEPER FORCING ALOFT AND THE LOCATION OF THE LOW LEVEL JET. THE
COMPLEX IS LIKELY TO DROP A WELL DEFINED COLD POOL AND THERE IS A
POSSIBILITY THAT THIS COULD WORK INTO NORTHERN PORTIONS OF THE
FORECAST AREA BEFORE WEAKENING. AT THIS POINT...ANTICIPATE A
WEAKENING LINE OF STORMS IMPACTING THE FORECAST AREA LATE FRIDAY
NIGHT WITH THE POTENTIAL FOR STORMS TO PRODUCE DAMAGING WINDS.
THE FRONT WILL SLOW DOWN ITS FORWARD PROGRESS AS IT RUNS INTO THE
SUPPRESSED RIDGE TO OUR SOUTH. BOUNDARY LIKELY TO TAKE ALL DAY
SATURDAY AND LIKELY A PORTION OF SATURDAY NIGHT TO MOVE ACROSS THE
FORECAST AREA. LEFTOVER CONVECTION FROM FRIDAY NIGHT MAY BE ONGOING
IN A WEAKENED STATE SATURDAY MORNING...BUT EXPECT RENEWED
DEVELOPMENT THROUGHOUT THE DAY. PRECIP WATER VALUES NEAR 2
INCHES...LOW LEVEL CONVERGENCE IN VICINITY OF THE FRONT AND MODEST
INSTABILITY WILL BE THE MAIN CATALYSTS FOR CONVECTIVE DEVELOPMENT
AND INTENSITY AS DEEPER FORCING ALOFT WILL BE FOCUSED FURTHER TO THE
NORTHEAST OVER THE EASTERN GREAT LAKES AND INTO NEW ENGLAND. WHILE
STORMS WILL HAVE THE POTENTIAL TO PRODUCE DAMAGING WINDS...NOT
EXPECTING A WIDESPREAD SEVERE THREAT IN THE ABSENCE OF DEEPER SHEAR
AND BETTER FORCING ALOFT. POTENTIAL FOR HEAVY RAINFALL AND LOCALIZED
FLOODING WITH THE HIGH PWATS. WILL CARRY HIGH CHANCE/LIKELY POPS
SATURDAY...WITH PRECIP CHANCES ENDING LATE SATURDAY NIGHT AS THE
FRONT SETTLES NEAR THE OHIO RIVER.
TEMPS...SEVERAL FACTORS SUGGESTIVE THAT FRIDAY COULD BE THE HOTTEST
DAY OF THIS RECENT STRETCH OF HOT DAYS FOR MUCH OF THE FORECAST AREA.
850MB TEMPS RISE TO 20-21C AND COMBINED WITH THE STRONGER W/SW FLOW
WHICH SHOULD ENHANCE BOUNDARY LAYER MIXING AND COMPRESSIONAL HEATING
AHEAD OF THE FRONT...COULD VERY WELL SEE TEMPS MAX OUT AT 94-95 IN
SOME LOCATIONS. MOS GUIDANCE LOOKS FAR TOO COOL AND WILL GENERALLY
BE 2-3 DEGREES WARMER. MOS GUIDANCE WITH HIGHS MAINLY IN THE UPPER
80S LOOKED REASONABLE FOR SATURDAY WITH STORMS AND INCREASED CLOUD
COVERAGE. LOWS WILL REMAIN IN THE 70S TONIGHT AND FRIDAY NIGHT...
FALLING BACK INTO THE 60S SATURDAY NIGHT AS COOLER DRIER AIR EXPANDS
SOUTH BEHIND THE FRONT.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 237 PM EDT THU JUL 18 2013
THE LONG TERM FORECAST IS CHARACTERIZED BY NORTHWEST FLOW ALOFT AND
A SERIES OF UPPER DISTURBANCES MOVING THROUGH THIS FLOW AND
PROMPTING THUNDERSTORM CHANCES. GENERALLY ACCEPTED ALLBLEND AS
TIMING OUT INDIVIDUAL WAVES OF THUNDERSTORMS IN THIS TYPE OF PATTERN
IS DIFFICULT ESPECIALLY WITH MODEL DISAGREEMENTS ON TIMING. HIGH
TEMPERATURES LOOK LIKE THEY WILL BE A COUPLE DEGREES BELOW NORMAL
FOR THE PERIOD WITH THICKNESSES LOWER IN THE NORTHWEST FLOW.
&&
.AVIATION /DISCUSSION FOR 181800Z TAF ISSUANCE/...
ISSUED AT 1250 PM EDT THU JUL 18 2013
BROAD HIGH PRESSURE CONTINUES OVER THE SITES. VFR CU SHOULD BE
AROUND FOR THE AFTERNOON BUT DISSIPATE WITH SUNSET. LIGHT AND
VARIABLE TO CALM WINDS OVERNIGHT WITH MOIST AIR AT LOW LEVELS UNDER
SUBSIDENCE WILL PRODUCE CONDITIONS VERY SIMILAR TO THIS MORNING SO
USED PERSISTENCE FOR OVERNIGHT FOG FORECAST. WILL BRING IN MVFR
FOG AT OUTLYING SITES SOMETIME AFTER 7Z. WILL ALSO INCLUDE SOME
IFR AT KLAF SIMILAR TO THIS MORNING. FRIDAY AFTERNOON CU WILL FORM
ONCE AGAIN AND COULD SEE A CHANCE FOR THUNDER BUT IS LOW ENOUGH TO
KEEP OUT OF THE FORECAST FOR NOW.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...SMF/RYAN
SHORT TERM...RYAN
LONG TERM....CP
AVIATION...CP
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
102 PM EDT THU JUL 18 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 346 AM EDT THU JUL 18 2013
HOT AND HUMID WEATHER WILL CONTINUE THROUGH FRIDAY AS THE RIDGE
ALOFT GRADUALLY SHIFTS TO THE SOUTH. A VIGOROUS UPPER LEVEL LOW WILL
TRACK THROUGH EASTERN CANADA WITH A COLD FRONT TRACKING SOUTH INTO
THE REGION ON SATURDAY. THE ARRIVAL AND PASSAGE OF THE FRONT WILL
BRING NUMEROUS SHOWERS AND THUNDERSTORMS TO CENTRAL INDIANA LATE
FRIDAY NIGHT THROUGH SATURDAY EVENING. COOLER DRIER AIR WILL BRIEFLY
BUILD INTO THE REGION ON SUNDAY AS HIGH PRESSURE PASSES THROUGH THE
GREAT LAKES. CHANCES FOR THUNDERSTORMS WILL RETURN BY LATE SUNDAY
NIGHT AND MONDAY AND CONTINUE THROUGH THE MIDDLE OF NEXT WEEK AS THE
FRONTAL BOUNDARY DRIFTS BACK NORTH INTO THE AREA.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1042 AM EDT THU JUL 18 2013
FEW IF ANY CHANGES NEEDED AT THIS TIME. FORECAST APPEARS TO BE IN
GOOD SHAPE. PREVIOUS DISCUSSION FOLLOWS...
ANOTHER MUGGY START EARLY THIS MORNING AS 07Z TEMPS GENERALLY IN THE
MID AND UPPER 70S. CONVECTIVE DEBRIS CLOUDS CONTINUE TO DRIFT INTO
THE SOUTHERN HALF OF THE FORECAST AREA AS A WEAK UPPER WAVE
CURRENTLY TRACKS ACROSS THE TENNESSEE VALLEY.
THE UPPER LEVEL HIGH REMAINS PARKED ACROSS CENTRAL INDIANA WITH MID
LEVEL HEIGHT MAXES STILL AROUND 597DAM. THESE HEIGHTS WILL SLOWLY
FALL THROUGH THE DAY AS THE RIDGE GRADUALLY BUCKLES IN RESPONSE TO A
DEVELOPING STRONG UPPER LOW GETTING ITS ACT TOGETHER ACROSS JAMES
BAY. THE AFOREMENTIONED WEAK WAVE ALOFT OVER THE TENNESSEE VALLEY
WILL DRIFT WEST THROUGH THE DAY AND SHOULD BE LOCATED OVER THE LOWER
OHIO VALLEY BY LATE DAY. SCATTERED CONVECTION ASSOCIATED WITH THIS
FEATURE SHOULD DEVELOP ACROSS KENTUCKY AND TENNESSEE AND MAY EVEN
SEE A FEW STORMS MAKE IT INTO OUR SOUTHERN COUNTIES. THE HRRR LOOKS
TO BE OVERDOING CONVECTIVE DEVELOPMENT IN GENERAL BUT HINTS AT THIS
IDEA AS WELL. CONSIDERING THE NATURE OF THE AIRMASS AND THE
PROXIMITY OF THE UPPER WAVE...ISOLATED POPS ARE WARRANTED ACROSS FAR
SOUTHERN COUNTIES FOR THIS AFTERNOON. FURTHER NORTH DESPITE THE
GRADUALLY LOWERING MID LEVEL HEIGHTS...THE RIDGING ALOFT AND CAP
NEAR 650MB ARE LIKELY TO REMAIN TOO STRONG FOR ANY SUBSTANTIAL
CONVECTIVE DEVELOPMENT. WHILE AN ISOLATED SHOWER CANNOT BE RULED
OUT...COVERAGE LIKELY TO BE SO LOW TO PRECLUDE ANY MENTION IN THE
FORECAST AT THIS TIME.
TEMPS...LOW LEVEL THERMALS WILL BE SIMILAR TO WEDNESDAY WITH 850MB
TEMPS RISING TO AROUND 19-20C. LIKEWISE EXPECT HIGH TEMPS TO BE
SIMILAR TO WEDNESDAY AS WELL...REACHING THE 92-94 DEGREE RANGE FOR
MUCH OF THE FORECAST AREA. GENERALLY GOING A DEGREE OR TWO ABOVE
MOS. MAX HEAT INDICES WILL RISE TO AROUND 100 DEGREES AGAIN THIS
AFTERNOON...AND MAY TOP OUT JUST A TOUCH WARMER THAN WEDNESDAY AS
SLIGHTLY DEEPER MOISTURE IS PULLED NORTH INTO THE REGION. HAVE NO
PLANS TO INTRODUCE A HEAT ADVISORY AS THESE VALUES REMAINS BELOW
CRITERIA. WILL CONTINUE WITH THE SPS.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 346 AM EDT THU JUL 18 2013
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES AND TEMPS AS A COLD
FRONT DROPS SOUTH THROUGH THE REGION SATURDAY. MODELS GENERALLY IN
VERY GOOD AGREEMENT ON MAIN FEATURES THROUGHOUT THE SHORT TERM.
RIDGING ALOFT WILL CONTINUE TO SINK SOUTH AND FLATTEN AS THE DEEP
UPPER LOW DIVES ACROSS NORTHERN ONTARIO...THEN PINWHEELS INTO THE
CANADIAN MARITIMES BY SUNDAY MORNING. ROBUST CONVECTIVE DEVELOPMENT
WILL TAKE PLACE TONIGHT OVER THE UPPER MISSISSIPPI VALLEY AND
NORTHERN GREAT LAKES IN PROXIMITY TO THE COLD FRONT. THIS FRONT WILL
SINK SOUTH AND SHOULD BE LOCATED ACROSS THE WESTERN GREAT LAKES BY
FRIDAY AFTERNOON. THE FLATTENING OF THE RIDGE AND APPROACH OF THE
COLD FRONT WILL ENCOURAGE A W/SW FLOW THROUGH THE LOWER LEVELS ON
FRIDAY...WITH POTENTIAL FOR SOME GUSTS TO NEAR 20-25KTS OVER
NORTHERN COUNTIES BY AFTERNOON AS A LOW LEVEL JET ACCOMPANIES THE
BOUNDARY THROUGH THE GREAT LAKES. WILL MAINTAIN LOW CHANCE POPS FOR
ISOLATED CONVECTIVE DEVELOPMENT FRIDAY AFTERNOON...BUT ANTICIPATE IT
WILL BE MORE FOCUSED OVER THE SOUTHERN HALF OF THE FORECAST AREA
WHERE DEEPER MOISTURE WILL RESIDE. THE W/SW FLOW WILL DRAW A SLUG OF
DRIER AIR ALOFT INTO THE LOWER GREAT LAKES IMMEDIATELY AHEAD OF THE
FRONT THAT WILL GRADUALLY BECOME SQUEEZED BY MOISTURE ADVECTING
NORTH AROUND THE BACK SIDE OF THE BERMUDA HIGH AND MOISTURE POOLING
ALONG THE BOUNDARY. THIS MAY LIMIT CONVECTIVE DEVELOPMENT OVER
NORTHERN COUNTIES FOR MUCH OF THE DAY.
FOCUS WILL SHIFT TO THE N/NW OF THE REGION BY LATE FRIDAY AFTERNOON
AS CONVECTION IS LIKELY TO DEVELOP IN THE VICINITY OF THE BOUNDARY
AND QUICKLY BECOME SEVERE AS BL SHEAR VALUES ARE ENHANCED AND
AIRMASS WILL BE MODERATELY UNSTABLE. STORMS ARE LIKELY TO ORGANIZE
INTO A MESOSCALE CONVECTIVE COMPLEX BY FRIDAY EVENING WITH
THERMODYNAMIC PROFILES SUGGESTING THE POTENTIAL FOR A SIGNIFICANT
DAMAGING WIND THREAT AS THE STORMS MOVE ACROSS THE LOWER GREAT
LAKES. THIS CONVECTION SHOULD LARGELY REMAIN TO THE NORTH OF THE
FORECAST AREA THROUGH THE EVENING...WITH PRECIP CHANCES RISING AFTER
MIDNIGHT AS THE TAIL END OF THE COMPLEX SAGS SOUTH INTO THE REGION
WITH THE COLD FRONT. AT THIS POINT...THERE IS GREATER UNCERTAINTY AS
TO THE POTENTIAL FOR CONVECTION TO MAINTAIN ITS INTENSITY OVER THE
FORECAST AREA LATE FRIDAY NIGHT. THE CORE OF THE COMPLEX IS EXPECTED
TO TRACK ACROSS THE LOWER GREAT LAKES IN CLOSER PROXIMITY TO THE
DEEPER FORCING ALOFT AND THE LOCATION OF THE LOW LEVEL JET. THE
COMPLEX IS LIKELY TO DROP A WELL DEFINED COLD POOL AND THERE IS A
POSSIBILITY THAT THIS COULD WORK INTO NORTHERN PORTIONS OF THE
FORECAST AREA BEFORE WEAKENING. AT THIS POINT...ANTICIPATE A
WEAKENING LINE OF STORMS IMPACTING THE FORECAST AREA LATE FRIDAY
NIGHT WITH THE POTENTIAL FOR STORMS TO PRODUCE DAMAGING WINDS.
THE FRONT WILL SLOW DOWN ITS FORWARD PROGRESS AS IT RUNS INTO THE
SUPPRESSED RIDGE TO OUR SOUTH. BOUNDARY LIKELY TO TAKE ALL DAY
SATURDAY AND LIKELY A PORTION OF SATURDAY NIGHT TO MOVE ACROSS THE
FORECAST AREA. LEFTOVER CONVECTION FROM FRIDAY NIGHT MAY BE ONGOING
IN A WEAKENED STATE SATURDAY MORNING...BUT EXPECT RENEWED
DEVELOPMENT THROUGHOUT THE DAY. PRECIP WATER VALUES NEAR 2
INCHES...LOW LEVEL CONVERGENCE IN VICINITY OF THE FRONT AND MODEST
INSTABILITY WILL BE THE MAIN CATALYSTS FOR CONVECTIVE DEVELOPMENT
AND INTENSITY AS DEEPER FORCING ALOFT WILL BE FOCUSED FURTHER TO THE
NORTHEAST OVER THE EASTERN GREAT LAKES AND INTO NEW ENGLAND. WHILE
STORMS WILL HAVE THE POTENTIAL TO PRODUCE DAMAGING WINDS...NOT
EXPECTING A WIDESPREAD SEVERE THREAT IN THE ABSENCE OF DEEPER SHEAR
AND BETTER FORCING ALOFT. POTENTIAL FOR HEAVY RAINFALL AND LOCALIZED
FLOODING WITH THE HIGH PWATS. WILL CARRY HIGH CHANCE/LIKELY POPS
SATURDAY...WITH PRECIP CHANCES ENDING LATE SATURDAY NIGHT AS THE
FRONT SETTLES NEAR THE OHIO RIVER.
TEMPS...SEVERAL FACTORS SUGGESTIVE THAT FRIDAY COULD BE THE HOTTEST
DAY OF THIS RECENT STRETCH OF HOT DAYS FOR MUCH OF THE FORECAST AREA.
850MB TEMPS RISE TO 20-21C AND COMBINED WITH THE STRONGER W/SW FLOW
WHICH SHOULD ENHANCE BOUNDARY LAYER MIXING AND COMPRESSIONAL HEATING
AHEAD OF THE FRONT...COULD VERY WELL SEE TEMPS MAX OUT AT 94-95 IN
SOME LOCATIONS. MOS GUIDANCE LOOKS FAR TOO COOL AND WILL GENERALLY
BE 2-3 DEGREES WARMER. MOS GUIDANCE WITH HIGHS MAINLY IN THE UPPER
80S LOOKED REASONABLE FOR SATURDAY WITH STORMS AND INCREASED CLOUD
COVERAGE. LOWS WILL REMAIN IN THE 70S TONIGHT AND FRIDAY NIGHT...
FALLING BACK INTO THE 60S SATURDAY NIGHT AS COOLER DRIER AIR EXPANDS
SOUTH BEHIND THE FRONT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 305 AM EDT THU JUL 18 2013
TEMPERATURES WILL NOT BE QUITE AS HOT DURING THE LONG TERM AS THE
UPPER HIGH WILL BE OVER THE WESTERN U.S. AND HEIGHTS LOWER A LITTLE
ACROSS THE GREAT LAKES. A WEAK COLD FRONT WILL STALL ACROSS THE
GREAT LAKES SUNDAY AS HIGH PRESSURE MOVES EAST ACROSS THE GREAT
LAKES. ALL AREAS SHOULD REMAIN DRY UNDER THIS SITUATION SUNDAY.
AFTER SUNDAY WILL MENTION CHANCE POPS FROM LATE SUNDAY NIGHT THROUGH
DAY 7 AS A SERIES OF WEAK DISTURBANCES MOVE EAST ALONG THIS STALLED
FRONT. THERE IS SOME DISCREPANCY ON TIMING OF THESE DISTURBANCES
BETWEEN THE DIFFERENT MODELS. HOWEVER MODEL CONSENSUS SEEMS TO POINT
TOWARDS ONE OF THE MAIN DISTURBANCES MOVING THROUGH AROUND MONDAY
AND ANOTHER ONE EITHER MOVING ACROSS OUR REGION TUESDAY NIGHT OR
WEDNESDAY.
CUT ALL BLEND POPS A LITTLE SUNDAY AND SUNDAY EVENING.
OTHERWISE...I DID NOT MAKE ANY SIGNIFICANT CHANGES TO POPS OR
TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR 181800Z TAF ISSUANCE/...
ISSUED AT 1250 PM EDT THU JUL 18 2013
BROAD HIGH PRESSURE CONTINUES OVER THE SITES. VFR CU SHOULD BE
AROUND FOR THE AFTERNOON BUT DISSIPATE WITH SUNSET. LIGHT AND
VARIABLE TO CALM WINDS OVERNIGHT WITH MOIST AIR AT LOW LEVELS UNDER
SUBSIDENCE WILL PRODUCE CONDITIONS VERY SIMILAR TO THIS MORNING SO
USED PERSISTENCE FOR OVERNIGHT FOG FORECAST. WILL BRING IN MVFR
FOG AT OUTLYING SITES SOMETIME AFTER 7Z. WILL ALSO INCLUDE SOME
IFR AT KLAF SIMILAR TO THIS MORNING. FRIDAY AFTERNOON CU WILL FORM
ONCE AGAIN AND COULD SEE A CHANCE FOR THUNDER BUT IS LOW ENOUGH TO
KEEP OUT OF THE FORECAST FOR NOW.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...SMF/RYAN
SHORT TERM...RYAN
LONG TERM....JH
AVIATION...CP
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1043 AM EDT THU JUL 18 2013
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 346 AM EDT THU JUL 18 2013
HOT AND HUMID WEATHER WILL CONTINUE THROUGH FRIDAY AS THE RIDGE
ALOFT GRADUALLY SHIFTS TO THE SOUTH. A VIGOROUS UPPER LEVEL LOW WILL
TRACK THROUGH EASTERN CANADA WITH A COLD FRONT TRACKING SOUTH INTO
THE REGION ON SATURDAY. THE ARRIVAL AND PASSAGE OF THE FRONT WILL
BRING NUMEROUS SHOWERS AND THUNDERSTORMS TO CENTRAL INDIANA LATE
FRIDAY NIGHT THROUGH SATURDAY EVENING. COOLER DRIER AIR WILL BRIEFLY
BUILD INTO THE REGION ON SUNDAY AS HIGH PRESSURE PASSES THROUGH THE
GREAT LAKES. CHANCES FOR THUNDERSTORMS WILL RETURN BY LATE SUNDAY
NIGHT AND MONDAY AND CONTINUE THROUGH THE MIDDLE OF NEXT WEEK AS THE
FRONTAL BOUNDARY DRIFTS BACK NORTH INTO THE AREA.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1042 AM EDT THU JUL 18 2013
FEW IF ANY CHANGES NEEDED AT THIS TIME. FORECAST APPEARS TO BE IN
GOOD SHAPE. PREVIOUS DISCUSSION FOLLOWS...
ANOTHER MUGGY START EARLY THIS MORNING AS 07Z TEMPS GENERALLY IN THE
MID AND UPPER 70S. CONVECTIVE DEBRIS CLOUDS CONTINUE TO DRIFT INTO
THE SOUTHERN HALF OF THE FORECAST AREA AS A WEAK UPPER WAVE
CURRENTLY TRACKS ACROSS THE TENNESSEE VALLEY.
THE UPPER LEVEL HIGH REMAINS PARKED ACROSS CENTRAL INDIANA WITH MID
LEVEL HEIGHT MAXES STILL AROUND 597DAM. THESE HEIGHTS WILL SLOWLY
FALL THROUGH THE DAY AS THE RIDGE GRADUALLY BUCKLES IN RESPONSE TO A
DEVELOPING STRONG UPPER LOW GETTING ITS ACT TOGETHER ACROSS JAMES
BAY. THE AFOREMENTIONED WEAK WAVE ALOFT OVER THE TENNESSEE VALLEY
WILL DRIFT WEST THROUGH THE DAY AND SHOULD BE LOCATED OVER THE LOWER
OHIO VALLEY BY LATE DAY. SCATTERED CONVECTION ASSOCIATED WITH THIS
FEATURE SHOULD DEVELOP ACROSS KENTUCKY AND TENNESSEE AND MAY EVEN
SEE A FEW STORMS MAKE IT INTO OUR SOUTHERN COUNTIES. THE HRRR LOOKS
TO BE OVERDOING CONVECTIVE DEVELOPMENT IN GENERAL BUT HINTS AT THIS
IDEA AS WELL. CONSIDERING THE NATURE OF THE AIRMASS AND THE
PROXIMITY OF THE UPPER WAVE...ISOLATED POPS ARE WARRANTED ACROSS FAR
SOUTHERN COUNTIES FOR THIS AFTERNOON. FURTHER NORTH DESPITE THE
GRADUALLY LOWERING MID LEVEL HEIGHTS...THE RIDGING ALOFT AND CAP
NEAR 650MB ARE LIKELY TO REMAIN TOO STRONG FOR ANY SUBSTANTIAL
CONVECTIVE DEVELOPMENT. WHILE AN ISOLATED SHOWER CANNOT BE RULED
OUT...COVERAGE LIKELY TO BE SO LOW TO PRECLUDE ANY MENTION IN THE
FORECAST AT THIS TIME.
TEMPS...LOW LEVEL THERMALS WILL BE SIMILAR TO WEDNESDAY WITH 850MB
TEMPS RISING TO AROUND 19-20C. LIKEWISE EXPECT HIGH TEMPS TO BE
SIMILAR TO WEDNESDAY AS WELL...REACHING THE 92-94 DEGREE RANGE FOR
MUCH OF THE FORECAST AREA. GENERALLY GOING A DEGREE OR TWO ABOVE
MOS. MAX HEAT INDICES WILL RISE TO AROUND 100 DEGREES AGAIN THIS
AFTERNOON...AND MAY TOP OUT JUST A TOUCH WARMER THAN WEDNESDAY AS
SLIGHTLY DEEPER MOISTURE IS PULLED NORTH INTO THE REGION. HAVE NO
PLANS TO INTRODUCE A HEAT ADVISORY AS THESE VALUES REMAINS BELOW
CRITERIA. WILL CONTINUE WITH THE SPS.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 346 AM EDT THU JUL 18 2013
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES AND TEMPS AS A COLD
FRONT DROPS SOUTH THROUGH THE REGION SATURDAY. MODELS GENERALLY IN
VERY GOOD AGREEMENT ON MAIN FEATURES THROUGHOUT THE SHORT TERM.
RIDGING ALOFT WILL CONTINUE TO SINK SOUTH AND FLATTEN AS THE DEEP
UPPER LOW DIVES ACROSS NORTHERN ONTARIO...THEN PINWHEELS INTO THE
CANADIAN MARITIMES BY SUNDAY MORNING. ROBUST CONVECTIVE DEVELOPMENT
WILL TAKE PLACE TONIGHT OVER THE UPPER MISSISSIPPI VALLEY AND
NORTHERN GREAT LAKES IN PROXIMITY TO THE COLD FRONT. THIS FRONT WILL
SINK SOUTH AND SHOULD BE LOCATED ACROSS THE WESTERN GREAT LAKES BY
FRIDAY AFTERNOON. THE FLATTENING OF THE RIDGE AND APPROACH OF THE
COLD FRONT WILL ENCOURAGE A W/SW FLOW THROUGH THE LOWER LEVELS ON
FRIDAY...WITH POTENTIAL FOR SOME GUSTS TO NEAR 20-25KTS OVER
NORTHERN COUNTIES BY AFTERNOON AS A LOW LEVEL JET ACCOMPANIES THE
BOUNDARY THROUGH THE GREAT LAKES. WILL MAINTAIN LOW CHANCE POPS FOR
ISOLATED CONVECTIVE DEVELOPMENT FRIDAY AFTERNOON...BUT ANTICIPATE IT
WILL BE MORE FOCUSED OVER THE SOUTHERN HALF OF THE FORECAST AREA
WHERE DEEPER MOISTURE WILL RESIDE. THE W/SW FLOW WILL DRAW A SLUG OF
DRIER AIR ALOFT INTO THE LOWER GREAT LAKES IMMEDIATELY AHEAD OF THE
FRONT THAT WILL GRADUALLY BECOME SQUEEZED BY MOISTURE ADVECTING
NORTH AROUND THE BACK SIDE OF THE BERMUDA HIGH AND MOISTURE POOLING
ALONG THE BOUNDARY. THIS MAY LIMIT CONVECTIVE DEVELOPMENT OVER
NORTHERN COUNTIES FOR MUCH OF THE DAY.
FOCUS WILL SHIFT TO THE N/NW OF THE REGION BY LATE FRIDAY AFTERNOON
AS CONVECTION IS LIKELY TO DEVELOP IN THE VICINITY OF THE BOUNDARY
AND QUICKLY BECOME SEVERE AS BL SHEAR VALUES ARE ENHANCED AND
AIRMASS WILL BE MODERATELY UNSTABLE. STORMS ARE LIKELY TO ORGANIZE
INTO A MESOSCALE CONVECTIVE COMPLEX BY FRIDAY EVENING WITH
THERMODYNAMIC PROFILES SUGGESTING THE POTENTIAL FOR A SIGNIFICANT
DAMAGING WIND THREAT AS THE STORMS MOVE ACROSS THE LOWER GREAT
LAKES. THIS CONVECTION SHOULD LARGELY REMAIN TO THE NORTH OF THE
FORECAST AREA THROUGH THE EVENING...WITH PRECIP CHANCES RISING AFTER
MIDNIGHT AS THE TAIL END OF THE COMPLEX SAGS SOUTH INTO THE REGION
WITH THE COLD FRONT. AT THIS POINT...THERE IS GREATER UNCERTAINTY AS
TO THE POTENTIAL FOR CONVECTION TO MAINTAIN ITS INTENSITY OVER THE
FORECAST AREA LATE FRIDAY NIGHT. THE CORE OF THE COMPLEX IS EXPECTED
TO TRACK ACROSS THE LOWER GREAT LAKES IN CLOSER PROXIMITY TO THE
DEEPER FORCING ALOFT AND THE LOCATION OF THE LOW LEVEL JET. THE
COMPLEX IS LIKELY TO DROP A WELL DEFINED COLD POOL AND THERE IS A
POSSIBILITY THAT THIS COULD WORK INTO NORTHERN PORTIONS OF THE
FORECAST AREA BEFORE WEAKENING. AT THIS POINT...ANTICIPATE A
WEAKENING LINE OF STORMS IMPACTING THE FORECAST AREA LATE FRIDAY
NIGHT WITH THE POTENTIAL FOR STORMS TO PRODUCE DAMAGING WINDS.
THE FRONT WILL SLOW DOWN ITS FORWARD PROGRESS AS IT RUNS INTO THE
SUPPRESSED RIDGE TO OUR SOUTH. BOUNDARY LIKELY TO TAKE ALL DAY
SATURDAY AND LIKELY A PORTION OF SATURDAY NIGHT TO MOVE ACROSS THE
FORECAST AREA. LEFTOVER CONVECTION FROM FRIDAY NIGHT MAY BE ONGOING
IN A WEAKENED STATE SATURDAY MORNING...BUT EXPECT RENEWED
DEVELOPMENT THROUGHOUT THE DAY. PRECIP WATER VALUES NEAR 2
INCHES...LOW LEVEL CONVERGENCE IN VICINITY OF THE FRONT AND MODEST
INSTABILITY WILL BE THE MAIN CATALYSTS FOR CONVECTIVE DEVELOPMENT
AND INTENSITY AS DEEPER FORCING ALOFT WILL BE FOCUSED FURTHER TO THE
NORTHEAST OVER THE EASTERN GREAT LAKES AND INTO NEW ENGLAND. WHILE
STORMS WILL HAVE THE POTENTIAL TO PRODUCE DAMAGING WINDS...NOT
EXPECTING A WIDESPREAD SEVERE THREAT IN THE ABSENCE OF DEEPER SHEAR
AND BETTER FORCING ALOFT. POTENTIAL FOR HEAVY RAINFALL AND LOCALIZED
FLOODING WITH THE HIGH PWATS. WILL CARRY HIGH CHANCE/LIKELY POPS
SATURDAY...WITH PRECIP CHANCES ENDING LATE SATURDAY NIGHT AS THE
FRONT SETTLES NEAR THE OHIO RIVER.
TEMPS...SEVERAL FACTORS SUGGESTIVE THAT FRIDAY COULD BE THE HOTTEST
DAY OF THIS RECENT STRETCH OF HOT DAYS FOR MUCH OF THE FORECAST AREA.
850MB TEMPS RISE TO 20-21C AND COMBINED WITH THE STRONGER W/SW FLOW
WHICH SHOULD ENHANCE BOUNDARY LAYER MIXING AND COMPRESSIONAL HEATING
AHEAD OF THE FRONT...COULD VERY WELL SEE TEMPS MAX OUT AT 94-95 IN
SOME LOCATIONS. MOS GUIDANCE LOOKS FAR TOO COOL AND WILL GENERALLY
BE 2-3 DEGREES WARMER. MOS GUIDANCE WITH HIGHS MAINLY IN THE UPPER
80S LOOKED REASONABLE FOR SATURDAY WITH STORMS AND INCREASED CLOUD
COVERAGE. LOWS WILL REMAIN IN THE 70S TONIGHT AND FRIDAY NIGHT...
FALLING BACK INTO THE 60S SATURDAY NIGHT AS COOLER DRIER AIR EXPANDS
SOUTH BEHIND THE FRONT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 305 AM EDT THU JUL 18 2013
TEMPERATURES WILL NOT BE QUITE AS HOT DURING THE LONG TERM AS THE
UPPER HIGH WILL BE OVER THE WESTERN U.S. AND HEIGHTS LOWER A LITTLE
ACROSS THE GREAT LAKES. A WEAK COLD FRONT WILL STALL ACROSS THE
GREAT LAKES SUNDAY AS HIGH PRESSURE MOVES EAST ACROSS THE GREAT
LAKES. ALL AREAS SHOULD REMAIN DRY UNDER THIS SITUATION SUNDAY.
AFTER SUNDAY WILL MENTION CHANCE POPS FROM LATE SUNDAY NIGHT THROUGH
DAY 7 AS A SERIES OF WEAK DISTURBANCES MOVE EAST ALONG THIS STALLED
FRONT. THERE IS SOME DISCREPANCY ON TIMING OF THESE DISTURBANCES
BETWEEN THE DIFFERENT MODELS. HOWEVER MODEL CONSENSUS SEEMS TO POINT
TOWARDS ONE OF THE MAIN DISTURBANCES MOVING THROUGH AROUND MONDAY
AND ANOTHER ONE EITHER MOVING ACROSS OUR REGION TUESDAY NIGHT OR
WEDNESDAY.
CUT ALL BLEND POPS A LITTLE SUNDAY AND SUNDAY EVENING.
OTHERWISE...I DID NOT MAKE ANY SIGNIFICANT CHANGES TO POPS OR
TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR THE 181500Z TAF ISSUANCE/...
ISSUED AT 1026 AM EDT THU JUL 18 2013
TAF UPDATED TO TWEAK CURRENT CONDITIONS. PREVIOUS DISCUSSION
FOLLOWS...
VISIBILITY RESTRICTIONS POSSIBLE AT KBMG/KHUF/KLAF AFTER 06Z
TONIGHT. OTHERWISE...TAFS WILL BE VFR.
HIGH PRESSURE BOTH SURFACE AND ALOFT WILL CONTINUE ACROSS THE REGION.
EXPECT SCATTERED CU AROUND 4 THOUSAND MOST OF TODAY. PATTERN IS
VERY STAGNANT AND WILL LEAN HEAVILY TOWARDS PERSISTENCE. CU SHOULD
DISSIPATE SHORTLY AFTER SUNSET AND FOG WILL REDEVELOP AGAIN LATE
TONIGHT SIMILAR TO LAST NIGHT. WINDS WILL BE FROM THE WEST AT 5
KNOTS OR LESS TODAY AND LIGHT TONIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...SMF/RYAN
SHORT TERM...RYAN
LONG TERM....JH
AVIATION...JH/CP
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1026 AM EDT THU JUL 18 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 346 AM EDT THU JUL 18 2013
HOT AND HUMID WEATHER WILL CONTINUE THROUGH FRIDAY AS THE RIDGE
ALOFT GRADUALLY SHIFTS TO THE SOUTH. A VIGOROUS UPPER LEVEL LOW WILL
TRACK THROUGH EASTERN CANADA WITH A COLD FRONT TRACKING SOUTH INTO
THE REGION ON SATURDAY. THE ARRIVAL AND PASSAGE OF THE FRONT WILL
BRING NUMEROUS SHOWERS AND THUNDERSTORMS TO CENTRAL INDIANA LATE
FRIDAY NIGHT THROUGH SATURDAY EVENING. COOLER DRIER AIR WILL BRIEFLY
BUILD INTO THE REGION ON SUNDAY AS HIGH PRESSURE PASSES THROUGH THE
GREAT LAKES. CHANCES FOR THUNDERSTORMS WILL RETURN BY LATE SUNDAY
NIGHT AND MONDAY AND CONTINUE THROUGH THE MIDDLE OF NEXT WEEK AS THE
FRONTAL BOUNDARY DRIFTS BACK NORTH INTO THE AREA.
&&
.NEAR TERM /TODAY/...
ISSUED AT 346 AM EDT THU JUL 18 2013
ANOTHER MUGGY START EARLY THIS MORNING AS 07Z TEMPS GENERALLY IN THE
MID AND UPPER 70S. CONVECTIVE DEBRIS CLOUDS CONTINUE TO DRIFT INTO
THE SOUTHERN HALF OF THE FORECAST AREA AS A WEAK UPPER WAVE
CURRENTLY TRACKS ACROSS THE TENNESSEE VALLEY.
THE UPPER LEVEL HIGH REMAINS PARKED ACROSS CENTRAL INDIANA WITH MID
LEVEL HEIGHT MAXES STILL AROUND 597DAM. THESE HEIGHTS WILL SLOWLY
FALL THROUGH THE DAY AS THE RIDGE GRADUALLY BUCKLES IN RESPONSE TO A
DEVELOPING STRONG UPPER LOW GETTING ITS ACT TOGETHER ACROSS JAMES
BAY. THE AFOREMENTIONED WEAK WAVE ALOFT OVER THE TENNESSEE VALLEY
WILL DRIFT WEST THROUGH THE DAY AND SHOULD BE LOCATED OVER THE LOWER
OHIO VALLEY BY LATE DAY. SCATTERED CONVECTION ASSOCIATED WITH THIS
FEATURE SHOULD DEVELOP ACROSS KENTUCKY AND TENNESSEE AND MAY EVEN
SEE A FEW STORMS MAKE IT INTO OUR SOUTHERN COUNTIES. THE HRRR LOOKS
TO BE OVERDOING CONVECTIVE DEVELOPMENT IN GENERAL BUT HINTS AT THIS
IDEA AS WELL. CONSIDERING THE NATURE OF THE AIRMASS AND THE
PROXIMITY OF THE UPPER WAVE...ISOLATED POPS ARE WARRANTED ACROSS FAR
SOUTHERN COUNTIES FOR THIS AFTERNOON. FURTHER NORTH DESPITE THE
GRADUALLY LOWERING MID LEVEL HEIGHTS...THE RIDGING ALOFT AND CAP
NEAR 650MB ARE LIKELY TO REMAIN TOO STRONG FOR ANY SUBSTANTIAL
CONVECTIVE DEVELOPMENT. WHILE AN ISOLATED SHOWER CANNOT BE RULED
OUT...COVERAGE LIKELY TO BE SO LOW TO PRECLUDE ANY MENTION IN THE
FORECAST AT THIS TIME.
TEMPS...LOW LEVEL THERMALS WILL BE SIMILAR TO WEDNESDAY WITH 850MB
TEMPS RISING TO AROUND 19-20C. LIKEWISE EXPECT HIGH TEMPS TO BE
SIMILAR TO WEDNESDAY AS WELL...REACHING THE 92-94 DEGREE RANGE FOR
MUCH OF THE FORECAST AREA. GENERALLY GOING A DEGREE OR TWO ABOVE
MOS. MAX HEAT INDICES WILL RISE TO AROUND 100 DEGREES AGAIN THIS
AFTERNOON...AND MAY TOP OUT JUST A TOUCH WARMER THAN WEDNESDAY AS
SLIGHTLY DEEPER MOISTURE IS PULLED NORTH INTO THE REGION. HAVE NO
PLANS TO INTRODUCE A HEAT ADVISORY AS THESE VALUES REMAINS BELOW
CRITERIA. WILL CONTINUE WITH THE SPS.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 346 AM EDT THU JUL 18 2013
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES AND TEMPS AS A COLD
FRONT DROPS SOUTH THROUGH THE REGION SATURDAY. MODELS GENERALLY IN
VERY GOOD AGREEMENT ON MAIN FEATURES THROUGHOUT THE SHORT TERM.
RIDGING ALOFT WILL CONTINUE TO SINK SOUTH AND FLATTEN AS THE DEEP
UPPER LOW DIVES ACROSS NORTHERN ONTARIO...THEN PINWHEELS INTO THE
CANADIAN MARITIMES BY SUNDAY MORNING. ROBUST CONVECTIVE DEVELOPMENT
WILL TAKE PLACE TONIGHT OVER THE UPPER MISSISSIPPI VALLEY AND
NORTHERN GREAT LAKES IN PROXIMITY TO THE COLD FRONT. THIS FRONT WILL
SINK SOUTH AND SHOULD BE LOCATED ACROSS THE WESTERN GREAT LAKES BY
FRIDAY AFTERNOON. THE FLATTENING OF THE RIDGE AND APPROACH OF THE
COLD FRONT WILL ENCOURAGE A W/SW FLOW THROUGH THE LOWER LEVELS ON
FRIDAY...WITH POTENTIAL FOR SOME GUSTS TO NEAR 20-25KTS OVER
NORTHERN COUNTIES BY AFTERNOON AS A LOW LEVEL JET ACCOMPANIES THE
BOUNDARY THROUGH THE GREAT LAKES. WILL MAINTAIN LOW CHANCE POPS FOR
ISOLATED CONVECTIVE DEVELOPMENT FRIDAY AFTERNOON...BUT ANTICIPATE IT
WILL BE MORE FOCUSED OVER THE SOUTHERN HALF OF THE FORECAST AREA
WHERE DEEPER MOISTURE WILL RESIDE. THE W/SW FLOW WILL DRAW A SLUG OF
DRIER AIR ALOFT INTO THE LOWER GREAT LAKES IMMEDIATELY AHEAD OF THE
FRONT THAT WILL GRADUALLY BECOME SQUEEZED BY MOISTURE ADVECTING
NORTH AROUND THE BACK SIDE OF THE BERMUDA HIGH AND MOISTURE POOLING
ALONG THE BOUNDARY. THIS MAY LIMIT CONVECTIVE DEVELOPMENT OVER
NORTHERN COUNTIES FOR MUCH OF THE DAY.
FOCUS WILL SHIFT TO THE N/NW OF THE REGION BY LATE FRIDAY AFTERNOON
AS CONVECTION IS LIKELY TO DEVELOP IN THE VICINITY OF THE BOUNDARY
AND QUICKLY BECOME SEVERE AS BL SHEAR VALUES ARE ENHANCED AND
AIRMASS WILL BE MODERATELY UNSTABLE. STORMS ARE LIKELY TO ORGANIZE
INTO A MESOSCALE CONVECTIVE COMPLEX BY FRIDAY EVENING WITH
THERMODYNAMIC PROFILES SUGGESTING THE POTENTIAL FOR A SIGNIFICANT
DAMAGING WIND THREAT AS THE STORMS MOVE ACROSS THE LOWER GREAT
LAKES. THIS CONVECTION SHOULD LARGELY REMAIN TO THE NORTH OF THE
FORECAST AREA THROUGH THE EVENING...WITH PRECIP CHANCES RISING AFTER
MIDNIGHT AS THE TAIL END OF THE COMPLEX SAGS SOUTH INTO THE REGION
WITH THE COLD FRONT. AT THIS POINT...THERE IS GREATER UNCERTAINTY AS
TO THE POTENTIAL FOR CONVECTION TO MAINTAIN ITS INTENSITY OVER THE
FORECAST AREA LATE FRIDAY NIGHT. THE CORE OF THE COMPLEX IS EXPECTED
TO TRACK ACROSS THE LOWER GREAT LAKES IN CLOSER PROXIMITY TO THE
DEEPER FORCING ALOFT AND THE LOCATION OF THE LOW LEVEL JET. THE
COMPLEX IS LIKELY TO DROP A WELL DEFINED COLD POOL AND THERE IS A
POSSIBILITY THAT THIS COULD WORK INTO NORTHERN PORTIONS OF THE
FORECAST AREA BEFORE WEAKENING. AT THIS POINT...ANTICIPATE A
WEAKENING LINE OF STORMS IMPACTING THE FORECAST AREA LATE FRIDAY
NIGHT WITH THE POTENTIAL FOR STORMS TO PRODUCE DAMAGING WINDS.
THE FRONT WILL SLOW DOWN ITS FORWARD PROGRESS AS IT RUNS INTO THE
SUPPRESSED RIDGE TO OUR SOUTH. BOUNDARY LIKELY TO TAKE ALL DAY
SATURDAY AND LIKELY A PORTION OF SATURDAY NIGHT TO MOVE ACROSS THE
FORECAST AREA. LEFTOVER CONVECTION FROM FRIDAY NIGHT MAY BE ONGOING
IN A WEAKENED STATE SATURDAY MORNING...BUT EXPECT RENEWED
DEVELOPMENT THROUGHOUT THE DAY. PRECIP WATER VALUES NEAR 2
INCHES...LOW LEVEL CONVERGENCE IN VICINITY OF THE FRONT AND MODEST
INSTABILITY WILL BE THE MAIN CATALYSTS FOR CONVECTIVE DEVELOPMENT
AND INTENSITY AS DEEPER FORCING ALOFT WILL BE FOCUSED FURTHER TO THE
NORTHEAST OVER THE EASTERN GREAT LAKES AND INTO NEW ENGLAND. WHILE
STORMS WILL HAVE THE POTENTIAL TO PRODUCE DAMAGING WINDS...NOT
EXPECTING A WIDESPREAD SEVERE THREAT IN THE ABSENCE OF DEEPER SHEAR
AND BETTER FORCING ALOFT. POTENTIAL FOR HEAVY RAINFALL AND LOCALIZED
FLOODING WITH THE HIGH PWATS. WILL CARRY HIGH CHANCE/LIKELY POPS
SATURDAY...WITH PRECIP CHANCES ENDING LATE SATURDAY NIGHT AS THE
FRONT SETTLES NEAR THE OHIO RIVER.
TEMPS...SEVERAL FACTORS SUGGESTIVE THAT FRIDAY COULD BE THE HOTTEST
DAY OF THIS RECENT STRETCH OF HOT DAYS FOR MUCH OF THE FORECAST AREA.
850MB TEMPS RISE TO 20-21C AND COMBINED WITH THE STRONGER W/SW FLOW
WHICH SHOULD ENHANCE BOUNDARY LAYER MIXING AND COMPRESSIONAL HEATING
AHEAD OF THE FRONT...COULD VERY WELL SEE TEMPS MAX OUT AT 94-95 IN
SOME LOCATIONS. MOS GUIDANCE LOOKS FAR TOO COOL AND WILL GENERALLY
BE 2-3 DEGREES WARMER. MOS GUIDANCE WITH HIGHS MAINLY IN THE UPPER
80S LOOKED REASONABLE FOR SATURDAY WITH STORMS AND INCREASED CLOUD
COVERAGE. LOWS WILL REMAIN IN THE 70S TONIGHT AND FRIDAY NIGHT...
FALLING BACK INTO THE 60S SATURDAY NIGHT AS COOLER DRIER AIR EXPANDS
SOUTH BEHIND THE FRONT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 305 AM EDT THU JUL 18 2013
TEMPERATURES WILL NOT BE QUITE AS HOT DURING THE LONG TERM AS THE
UPPER HIGH WILL BE OVER THE WESTERN U.S. AND HEIGHTS LOWER A LITTLE
ACROSS THE GREAT LAKES. A WEAK COLD FRONT WILL STALL ACROSS THE
GREAT LAKES SUNDAY AS HIGH PRESSURE MOVES EAST ACROSS THE GREAT
LAKES. ALL AREAS SHOULD REMAIN DRY UNDER THIS SITUATION SUNDAY.
AFTER SUNDAY WILL MENTION CHANCE POPS FROM LATE SUNDAY NIGHT THROUGH
DAY 7 AS A SERIES OF WEAK DISTURBANCES MOVE EAST ALONG THIS STALLED
FRONT. THERE IS SOME DISCREPANCY ON TIMING OF THESE DISTURBANCES
BETWEEN THE DIFFERENT MODELS. HOWEVER MODEL CONSENSUS SEEMS TO POINT
TOWARDS ONE OF THE MAIN DISTURBANCES MOVING THROUGH AROUND MONDAY
AND ANOTHER ONE EITHER MOVING ACROSS OUR REGION TUESDAY NIGHT OR
WEDNESDAY.
CUT ALL BLEND POPS A LITTLE SUNDAY AND SUNDAY EVENING.
OTHERWISE...I DID NOT MAKE ANY SIGNIFICANT CHANGES TO POPS OR
TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR THE 181500Z TAF ISSUANCE/...
ISSUED AT 1026 AM EDT THU JUL 18 2013
TAF UPDATED TO TWEAK CURRENT CONDITIONS. PREVIOUS DISCUSSION
FOLLOWS...
VISIBILITY RESTRICTIONS POSSIBLE AT KBMG/KHUF/KLAF AFTER 06Z
TONIGHT. OTHERWISE...TAFS WILL BE VFR.
HIGH PRESSURE BOTH SURFACE AND ALOFT WILL CONTINUE ACROSS THE REGION.
EXPECT SCATTERED CU AROUND 4 THOUSAND MOST OF TODAY. PATTERN IS
VERY STAGNANT AND WILL LEAN HEAVILY TOWARDS PERSISTENCE. CU SHOULD
DISSIPATE SHORTLY AFTER SUNSET AND FOG WILL REDEVELOP AGAIN LATE
TONIGHT SIMILAR TO LAST NIGHT. WINDS WILL BE FROM THE WEST AT 5
KNOTS OR LESS TODAY AND LIGHT TONIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....JH
AVIATION...JH/CP
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
650 AM EDT THU JUL 18 2013
.UPDATE...
AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 346 AM EDT THU JUL 18 2013
HOT AND HUMID WEATHER WILL CONTINUE THROUGH FRIDAY AS THE RIDGE
ALOFT GRADUALLY SHIFTS TO THE SOUTH. A VIGOROUS UPPER LEVEL LOW WILL
TRACK THROUGH EASTERN CANADA WITH A COLD FRONT TRACKING SOUTH INTO
THE REGION ON SATURDAY. THE ARRIVAL AND PASSAGE OF THE FRONT WILL
BRING NUMEROUS SHOWERS AND THUNDERSTORMS TO CENTRAL INDIANA LATE
FRIDAY NIGHT THROUGH SATURDAY EVENING. COOLER DRIER AIR WILL BRIEFLY
BUILD INTO THE REGION ON SUNDAY AS HIGH PRESSURE PASSES THROUGH THE
GREAT LAKES. CHANCES FOR THUNDERSTORMS WILL RETURN BY LATE SUNDAY
NIGHT AND MONDAY AND CONTINUE THROUGH THE MIDDLE OF NEXT WEEK AS THE
FRONTAL BOUNDARY DRIFTS BACK NORTH INTO THE AREA.
&&
.NEAR TERM /TODAY/...
ISSUED AT 346 AM EDT THU JUL 18 2013
ANOTHER MUGGY START EARLY THIS MORNING AS 07Z TEMPS GENERALLY IN THE
MID AND UPPER 70S. CONVECTIVE DEBRIS CLOUDS CONTINUE TO DRIFT INTO
THE SOUTHERN HALF OF THE FORECAST AREA AS A WEAK UPPER WAVE
CURRENTLY TRACKS ACROSS THE TENNESSEE VALLEY.
THE UPPER LEVEL HIGH REMAINS PARKED ACROSS CENTRAL INDIANA WITH MID
LEVEL HEIGHT MAXES STILL AROUND 597DAM. THESE HEIGHTS WILL SLOWLY
FALL THROUGH THE DAY AS THE RIDGE GRADUALLY BUCKLES IN RESPONSE TO A
DEVELOPING STRONG UPPER LOW GETTING ITS ACT TOGETHER ACROSS JAMES
BAY. THE AFOREMENTIONED WEAK WAVE ALOFT OVER THE TENNESSEE VALLEY
WILL DRIFT WEST THROUGH THE DAY AND SHOULD BE LOCATED OVER THE LOWER
OHIO VALLEY BY LATE DAY. SCATTERED CONVECTION ASSOCIATED WITH THIS
FEATURE SHOULD DEVELOP ACROSS KENTUCKY AND TENNESSEE AND MAY EVEN
SEE A FEW STORMS MAKE IT INTO OUR SOUTHERN COUNTIES. THE HRRR LOOKS
TO BE OVERDOING CONVECTIVE DEVELOPMENT IN GENERAL BUT HINTS AT THIS
IDEA AS WELL. CONSIDERING THE NATURE OF THE AIRMASS AND THE
PROXIMITY OF THE UPPER WAVE...ISOLATED POPS ARE WARRANTED ACROSS FAR
SOUTHERN COUNTIES FOR THIS AFTERNOON. FURTHER NORTH DESPITE THE
GRADUALLY LOWERING MID LEVEL HEIGHTS...THE RIDGING ALOFT AND CAP
NEAR 650MB ARE LIKELY TO REMAIN TOO STRONG FOR ANY SUBSTANTIAL
CONVECTIVE DEVELOPMENT. WHILE AN ISOLATED SHOWER CANNOT BE RULED
OUT...COVERAGE LIKELY TO BE SO LOW TO PRECLUDE ANY MENTION IN THE
FORECAST AT THIS TIME.
TEMPS...LOW LEVEL THERMALS WILL BE SIMILAR TO WEDNESDAY WITH 850MB
TEMPS RISING TO AROUND 19-20C. LIKEWISE EXPECT HIGH TEMPS TO BE
SIMILAR TO WEDNESDAY AS WELL...REACHING THE 92-94 DEGREE RANGE FOR
MUCH OF THE FORECAST AREA. GENERALLY GOING A DEGREE OR TWO ABOVE
MOS. MAX HEAT INDICES WILL RISE TO AROUND 100 DEGREES AGAIN THIS
AFTERNOON...AND MAY TOP OUT JUST A TOUCH WARMER THAN WEDNESDAY AS
SLIGHTLY DEEPER MOISTURE IS PULLED NORTH INTO THE REGION. HAVE NO
PLANS TO INTRODUCE A HEAT ADVISORY AS THESE VALUES REMAINS BELOW
CRITERIA. WILL CONTINUE WITH THE SPS.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 346 AM EDT THU JUL 18 2013
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES AND TEMPS AS A COLD
FRONT DROPS SOUTH THROUGH THE REGION SATURDAY. MODELS GENERALLY IN
VERY GOOD AGREEMENT ON MAIN FEATURES THROUGHOUT THE SHORT TERM.
RIDGING ALOFT WILL CONTINUE TO SINK SOUTH AND FLATTEN AS THE DEEP
UPPER LOW DIVES ACROSS NORTHERN ONTARIO...THEN PINWHEELS INTO THE
CANADIAN MARITIMES BY SUNDAY MORNING. ROBUST CONVECTIVE DEVELOPMENT
WILL TAKE PLACE TONIGHT OVER THE UPPER MISSISSIPPI VALLEY AND
NORTHERN GREAT LAKES IN PROXIMITY TO THE COLD FRONT. THIS FRONT WILL
SINK SOUTH AND SHOULD BE LOCATED ACROSS THE WESTERN GREAT LAKES BY
FRIDAY AFTERNOON. THE FLATTENING OF THE RIDGE AND APPROACH OF THE
COLD FRONT WILL ENCOURAGE A W/SW FLOW THROUGH THE LOWER LEVELS ON
FRIDAY...WITH POTENTIAL FOR SOME GUSTS TO NEAR 20-25KTS OVER
NORTHERN COUNTIES BY AFTERNOON AS A LOW LEVEL JET ACCOMPANIES THE
BOUNDARY THROUGH THE GREAT LAKES. WILL MAINTAIN LOW CHANCE POPS FOR
ISOLATED CONVECTIVE DEVELOPMENT FRIDAY AFTERNOON...BUT ANTICIPATE IT
WILL BE MORE FOCUSED OVER THE SOUTHERN HALF OF THE FORECAST AREA
WHERE DEEPER MOISTURE WILL RESIDE. THE W/SW FLOW WILL DRAW A SLUG OF
DRIER AIR ALOFT INTO THE LOWER GREAT LAKES IMMEDIATELY AHEAD OF THE
FRONT THAT WILL GRADUALLY BECOME SQUEEZED BY MOISTURE ADVECTING NORTH
AROUND THE BACK SIDE OF THE BERMUDA HIGH AND MOISTURE POOLING ALONG
THE BOUNDARY. THIS MAY LIMIT CONVECTIVE DEVELOPMENT OVER NORTHERN
COUNTIES FOR MUCH OF THE DAY.
FOCUS WILL SHIFT TO THE N/NW OF THE REGION BY LATE FRIDAY AFTERNOON
AS CONVECTION IS LIKELY TO DEVELOP IN THE VICINITY OF THE BOUNDARY
AND QUICKLY BECOME SEVERE AS BL SHEAR VALUES ARE ENHANCED AND
AIRMASS WILL BE MODERATELY UNSTABLE. STORMS ARE LIKELY TO ORGANIZE
INTO A MESOSCALE CONVECTIVE COMPLEX BY FRIDAY EVENING WITH
THERMODYNAMIC PROFILES SUGGESTING THE POTENTIAL FOR A SIGNIFICANT
DAMAGING WIND THREAT AS THE STORMS MOVE ACROSS THE LOWER GREAT
LAKES. THIS CONVECTION SHOULD LARGELY REMAIN TO THE NORTH OF THE
FORECAST AREA THROUGH THE EVENING...WITH PRECIP CHANCES RISING AFTER
MIDNIGHT AS THE TAIL END OF THE COMPLEX SAGS SOUTH INTO THE REGION
WITH THE COLD FRONT. AT THIS POINT...THERE IS GREATER UNCERTAINTY AS
TO THE POTENTIAL FOR CONVECTION TO MAINTAIN ITS INTENSITY OVER THE
FORECAST AREA LATE FRIDAY NIGHT. THE CORE OF THE COMPLEX IS EXPECTED
TO TRACK ACROSS THE LOWER GREAT LAKES IN CLOSER PROXIMITY TO THE
DEEPER FORCING ALOFT AND THE LOCATION OF THE LOW LEVEL JET. THE
COMPLEX IS LIKELY TO DROP A WELL DEFINED COLD POOL AND THERE IS A
POSSIBILITY THAT THIS COULD WORK INTO NORTHERN PORTIONS OF THE
FORECAST AREA BEFORE WEAKENING. AT THIS POINT...ANTICIPATE A
WEAKENING LINE OF STORMS IMPACTING THE FORECAST AREA LATE FRIDAY
NIGHT WITH THE POTENTIAL FOR STORMS TO PRODUCE DAMAGING WINDS.
THE FRONT WILL SLOW DOWN ITS FORWARD PROGRESS AS IT RUNS INTO THE
SUPPRESSED RIDGE TO OUR SOUTH. BOUNDARY LIKELY TO TAKE ALL DAY
SATURDAY AND LIKELY A PORTION OF SATURDAY NIGHT TO MOVE ACROSS THE
FORECAST AREA. LEFTOVER CONVECTION FROM FRIDAY NIGHT MAY BE ONGOING
IN A WEAKENED STATE SATURDAY MORNING...BUT EXPECT RENEWED
DEVELOPMENT THROUGHOUT THE DAY. PRECIP WATER VALUES NEAR 2
INCHES...LOW LEVEL CONVERGENCE IN VICINITY OF THE FRONT AND MODEST
INSTABILITY WILL BE THE MAIN CATALYSTS FOR CONVECTIVE DEVELOPMENT
AND INTENSITY AS DEEPER FORCING ALOFT WILL BE FOCUSED FURTHER TO THE
NORTHEAST OVER THE EASTERN GREAT LAKES AND INTO NEW ENGLAND. WHILE
STORMS WILL HAVE THE POTENTIAL TO PRODUCE DAMAGING WINDS...NOT
EXPECTING A WIDESPREAD SEVERE THREAT IN THE ABSENCE OF DEEPER SHEAR
AND BETTER FORCING ALOFT. POTENTIAL FOR HEAVY RAINFALL AND LOCALIZED
FLOODING WITH THE HIGH PWATS. WILL CARRY HIGH CHANCE/LIKELY POPS
SATURDAY...WITH PRECIP CHANCES ENDING LATE SATURDAY NIGHT AS THE
FRONT SETTLES NEAR THE OHIO RIVER.
TEMPS...SEVERAL FACTORS SUGGESTIVE THAT FRIDAY COULD BE THE HOTTEST
DAY OF THIS RECENT STRETCH OF HOT DAYS FOR MUCH OF THE FORECAST AREA.
850MB TEMPS RISE TO 20-21C AND COMBINED WITH THE STRONGER W/SW FLOW
WHICH SHOULD ENHANCE BOUNDARY LAYER MIXING AND COMPRESSIONAL HEATING
AHEAD OF THE FRONT...COULD VERY WELL SEE TEMPS MAX OUT AT 94-95 IN
SOME LOCATIONS. MOS GUIDANCE LOOKS FAR TOO COOL AND WILL GENERALLY
BE 2-3 DEGREES WARMER. MOS GUIDANCE WITH HIGHS MAINLY IN THE UPPER
80S LOOKED REASONABLE FOR SATURDAY WITH STORMS AND INCREASED CLOUD
COVERAGE. LOWS WILL REMAIN IN THE 70S TONIGHT AND FRIDAY NIGHT...
FALLING BACK INTO THE 60S SATURDAY NIGHT AS COOLER DRIER AIR EXPANDS
SOUTH BEHIND THE FRONT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 305 AM EDT THU JUL 18 2013
TEMPERATURES WILL NOT BE QUITE AS HOT DURING THE LONG TERM AS THE
UPPER HIGH WILL BE OVER THE WESTERN U.S. AND HEIGHTS LOWER A LITTLE
ACROSS THE GREAT LAKES. A WEAK COLD FRONT WILL STALL ACROSS THE
GREAT LAKES SUNDAY AS HIGH PRESSURE MOVES EAST ACROSS THE GREAT
LAKES. ALL AREAS SHOULD REMAIN DRY UNDER THIS SITUATION SUNDAY.
AFTER SUNDAY WILL MENTION CHANCE POPS FROM LATE SUNDAY NIGHT THROUGH
DAY 7 AS A SERIES OF WEAK DISTURBANCES MOVE EAST ALONG THIS STALLED
FRONT. THERE IS SOME DISCREPANCY ON TIMING OF THESE DISTURBANCES
BETWEEN THE DIFFERENT MODELS. HOWEVER MODEL CONSENSUS SEEMS TO POINT
TOWARDS ONE OF THE MAIN DISTURBANCES MOVING THROUGH AROUND MONDAY
AND ANOTHER ONE EITHER MOVING ACROSS OUR REGION TUESDAY NIGHT OR
WEDNESDAY.
CUT ALL BLEND POPS A LITTLE SUNDAY AND SUNDAY EVENING.
OTHERWISE...I DID NOT MAKE ANY SIGNIFICANT CHANGES TO POPS OR
TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR THE 181200Z TAF ISSUANCE/...
ISSUED AT 650 AM EDT THU JUL 18 2013
VISIBILITY RESTRICTIONS POSSIBLE AT KBMG/KHUF/KLAF FOR THE 1ST HOUR
AND AGAIN AFTER 06Z TONIGHT. OTHERWISE...TAFS WILL BE VFR.
HIGH PRESSURE BOTH SURFACE AND ALOFT WILL CONTINUE ACROSS THE REGION.
DAYTIME HEATING SHOULD CLEAR OUT ANY FOG NEXT HOUR OR TWO. AFTER THAT
EXPECT SCATTERED CU AROUND 4 THOUSAND MOST OF TODAY. PATTERN IS VERY
STAGNANT AND WILL LEAN HEAVILY TOWARDS PERSISTENCE. CU SHOULD DISSIPATE
SHORTLY AFTER SUNSET AND FOG WILL REDEVELOP AGAIN LATE TONIGHT SIMILAR
TO LAST NIGHT. WINDS WILL BE FROM THE WEST AT 5 KNOTS OR LESS TODAY AND
LIGHT TONIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....JH
AVIATION...JH
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
427 AM EDT THU JUL 18 2013
.UPDATE...
AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 346 AM EDT THU JUL 18 2013
HOT AND HUMID WEATHER WILL CONTINUE THROUGH FRIDAY AS THE RIDGE
ALOFT GRADUALLY SHIFTS TO THE SOUTH. A VIGOROUS UPPER LEVEL LOW WILL
TRACK THROUGH EASTERN CANADA WITH A COLD FRONT TRACKING SOUTH INTO
THE REGION ON SATURDAY. THE ARRIVAL AND PASSAGE OF THE FRONT WILL
BRING NUMEROUS SHOWERS AND THUNDERSTORMS TO CENTRAL INDIANA LATE
FRIDAY NIGHT THROUGH SATURDAY EVENING. COOLER DRIER AIR WILL BRIEFLY
BUILD INTO THE REGION ON SUNDAY AS HIGH PRESSURE PASSES THROUGH THE
GREAT LAKES. CHANCES FOR THUNDERSTORMS WILL RETURN BY LATE SUNDAY
NIGHT AND MONDAY AND CONTINUE THROUGH THE MIDDLE OF NEXT WEEK AS THE
FRONTAL BOUNDARY DRIFTS BACK NORTH INTO THE AREA.
&&
.NEAR TERM /TODAY/...
ISSUED AT 346 AM EDT THU JUL 18 2013
ANOTHER MUGGY START EARLY THIS MORNING AS 07Z TEMPS GENERALLY IN THE
MID AND UPPER 70S. CONVECTIVE DEBRIS CLOUDS CONTINUE TO DRIFT INTO
THE SOUTHERN HALF OF THE FORECAST AREA AS A WEAK UPPER WAVE
CURRENTLY TRACKS ACROSS THE TENNESSEE VALLEY.
THE UPPER LEVEL HIGH REMAINS PARKED ACROSS CENTRAL INDIANA WITH MID
LEVEL HEIGHT MAXES STILL AROUND 597DAM. THESE HEIGHTS WILL SLOWLY
FALL THROUGH THE DAY AS THE RIDGE GRADUALLY BUCKLES IN RESPONSE TO A
DEVELOPING STRONG UPPER LOW GETTING ITS ACT TOGETHER ACROSS JAMES
BAY. THE AFOREMENTIONED WEAK WAVE ALOFT OVER THE TENNESSEE VALLEY
WILL DRIFT WEST THROUGH THE DAY AND SHOULD BE LOCATED OVER THE LOWER
OHIO VALLEY BY LATE DAY. SCATTERED CONVECTION ASSOCIATED WITH THIS
FEATURE SHOULD DEVELOP ACROSS KENTUCKY AND TENNESSEE AND MAY EVEN
SEE A FEW STORMS MAKE IT INTO OUR SOUTHERN COUNTIES. THE HRRR LOOKS
TO BE OVERDOING CONVECTIVE DEVELOPMENT IN GENERAL BUT HINTS AT THIS
IDEA AS WELL. CONSIDERING THE NATURE OF THE AIRMASS AND THE
PROXIMITY OF THE UPPER WAVE...ISOLATED POPS ARE WARRANTED ACROSS FAR
SOUTHERN COUNTIES FOR THIS AFTERNOON. FURTHER NORTH DESPITE THE
GRADUALLY LOWERING MID LEVEL HEIGHTS...THE RIDGING ALOFT AND CAP
NEAR 650MB ARE LIKELY TO REMAIN TOO STRONG FOR ANY SUBSTANTIAL
CONVECTIVE DEVELOPMENT. WHILE AN ISOLATED SHOWER CANNOT BE RULED
OUT...COVERAGE LIKELY TO BE SO LOW TO PRECLUDE ANY MENTION IN THE
FORECAST AT THIS TIME.
TEMPS...LOW LEVEL THERMALS WILL BE SIMILAR TO WEDNESDAY WITH 850MB
TEMPS RISING TO AROUND 19-20C. LIKEWISE EXPECT HIGH TEMPS TO BE
SIMILAR TO WEDNESDAY AS WELL...REACHING THE 92-94 DEGREE RANGE FOR
MUCH OF THE FORECAST AREA. GENERALLY GOING A DEGREE OR TWO ABOVE
MOS. MAX HEAT INDICES WILL RISE TO AROUND 100 DEGREES AGAIN THIS
AFTERNOON...AND MAY TOP OUT JUST A TOUCH WARMER THAN WEDNESDAY AS
SLIGHTLY DEEPER MOISTURE IS PULLED NORTH INTO THE REGION. HAVE NO
PLANS TO INTRODUCE A HEAT ADVISORY AS THESE VALUES REMAINS BELOW
CRITERIA. WILL CONTINUE WITH THE SPS.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 346 AM EDT THU JUL 18 2013
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES AND TEMPS AS A COLD
FRONT DROPS SOUTH THROUGH THE REGION SATURDAY. MODELS GENERALLY IN
VERY GOOD AGREEMENT ON MAIN FEATURES THROUGHOUT THE SHORT TERM.
RIDGING ALOFT WILL CONTINUE TO SINK SOUTH AND FLATTEN AS THE DEEP
UPPER LOW DIVES ACROSS NORTHERN ONTARIO...THEN PINWHEELS INTO THE
CANADIAN MARITIMES BY SUNDAY MORNING. ROBUST CONVECTIVE DEVELOPMENT
WILL TAKE PLACE TONIGHT OVER THE UPPER MISSISSIPPI VALLEY AND
NORTHERN GREAT LAKES IN PROXIMITY TO THE COLD FRONT. THIS FRONT WILL
SINK SOUTH AND SHOULD BE LOCATED ACROSS THE WESTERN GREAT LAKES BY
FRIDAY AFTERNOON. THE FLATTENING OF THE RIDGE AND APPROACH OF THE
COLD FRONT WILL ENCOURAGE A W/SW FLOW THROUGH THE LOWER LEVELS ON
FRIDAY...WITH POTENTIAL FOR SOME GUSTS TO NEAR 20-25KTS OVER
NORTHERN COUNTIES BY AFTERNOON AS A LOW LEVEL JET ACCOMPANIES THE
BOUNDARY THROUGH THE GREAT LAKES. WILL MAINTAIN LOW CHANCE POPS FOR
ISOLATED CONVECTIVE DEVELOPMENT FRIDAY AFTERNOON...BUT ANTICIPATE IT
WILL BE MORE FOCUSED OVER THE SOUTHERN HALF OF THE FORECAST AREA
WHERE DEEPER MOISTURE WILL RESIDE. THE W/SW FLOW WILL DRAW A SLUG OF
DRIER AIR ALOFT INTO THE LOWER GREAT LAKES IMMEDIATELY AHEAD OF THE
FRONT THAT WILL GRADUALLY BECOME SQUEEZED BY MOISTURE ADVECTING NORTH
AROUND THE BACK SIDE OF THE BERMUDA HIGH AND MOISTURE POOLING ALONG
THE BOUNDARY. THIS MAY LIMIT CONVECTIVE DEVELOPMENT OVER NORTHERN
COUNTIES FOR MUCH OF THE DAY.
FOCUS WILL SHIFT TO THE N/NW OF THE REGION BY LATE FRIDAY AFTERNOON
AS CONVECTION IS LIKELY TO DEVELOP IN THE VICINITY OF THE BOUNDARY
AND QUICKLY BECOME SEVERE AS BL SHEAR VALUES ARE ENHANCED AND
AIRMASS WILL BE MODERATELY UNSTABLE. STORMS ARE LIKELY TO ORGANIZE
INTO A MESOSCALE CONVECTIVE COMPLEX BY FRIDAY EVENING WITH
THERMODYNAMIC PROFILES SUGGESTING THE POTENTIAL FOR A SIGNIFICANT
DAMAGING WIND THREAT AS THE STORMS MOVE ACROSS THE LOWER GREAT
LAKES. THIS CONVECTION SHOULD LARGELY REMAIN TO THE NORTH OF THE
FORECAST AREA THROUGH THE EVENING...WITH PRECIP CHANCES RISING AFTER
MIDNIGHT AS THE TAIL END OF THE COMPLEX SAGS SOUTH INTO THE REGION
WITH THE COLD FRONT. AT THIS POINT...THERE IS GREATER UNCERTAINTY AS
TO THE POTENTIAL FOR CONVECTION TO MAINTAIN ITS INTENSITY OVER THE
FORECAST AREA LATE FRIDAY NIGHT. THE CORE OF THE COMPLEX IS EXPECTED
TO TRACK ACROSS THE LOWER GREAT LAKES IN CLOSER PROXIMITY TO THE
DEEPER FORCING ALOFT AND THE LOCATION OF THE LOW LEVEL JET. THE
COMPLEX IS LIKELY TO DROP A WELL DEFINED COLD POOL AND THERE IS A
POSSIBILITY THAT THIS COULD WORK INTO NORTHERN PORTIONS OF THE
FORECAST AREA BEFORE WEAKENING. AT THIS POINT...ANTICIPATE A
WEAKENING LINE OF STORMS IMPACTING THE FORECAST AREA LATE FRIDAY
NIGHT WITH THE POTENTIAL FOR STORMS TO PRODUCE DAMAGING WINDS.
THE FRONT WILL SLOW DOWN ITS FORWARD PROGRESS AS IT RUNS INTO THE
SUPPRESSED RIDGE TO OUR SOUTH. BOUNDARY LIKELY TO TAKE ALL DAY
SATURDAY AND LIKELY A PORTION OF SATURDAY NIGHT TO MOVE ACROSS THE
FORECAST AREA. LEFTOVER CONVECTION FROM FRIDAY NIGHT MAY BE ONGOING
IN A WEAKENED STATE SATURDAY MORNING...BUT EXPECT RENEWED
DEVELOPMENT THROUGHOUT THE DAY. PRECIP WATER VALUES NEAR 2
INCHES...LOW LEVEL CONVERGENCE IN VICINITY OF THE FRONT AND MODEST
INSTABILITY WILL BE THE MAIN CATALYSTS FOR CONVECTIVE DEVELOPMENT
AND INTENSITY AS DEEPER FORCING ALOFT WILL BE FOCUSED FURTHER TO THE
NORTHEAST OVER THE EASTERN GREAT LAKES AND INTO NEW ENGLAND. WHILE
STORMS WILL HAVE THE POTENTIAL TO PRODUCE DAMAGING WINDS...NOT
EXPECTING A WIDESPREAD SEVERE THREAT IN THE ABSENCE OF DEEPER SHEAR
AND BETTER FORCING ALOFT. POTENTIAL FOR HEAVY RAINFALL AND LOCALIZED
FLOODING WITH THE HIGH PWATS. WILL CARRY HIGH CHANCE/LIKELY POPS
SATURDAY...WITH PRECIP CHANCES ENDING LATE SATURDAY NIGHT AS THE
FRONT SETTLES NEAR THE OHIO RIVER.
TEMPS...SEVERAL FACTORS SUGGESTIVE THAT FRIDAY COULD BE THE HOTTEST
DAY OF THIS RECENT STRETCH OF HOT DAYS FOR MUCH OF THE FORECAST AREA.
850MB TEMPS RISE TO 20-21C AND COMBINED WITH THE STRONGER W/SW FLOW
WHICH SHOULD ENHANCE BOUNDARY LAYER MIXING AND COMPRESSIONAL HEATING
AHEAD OF THE FRONT...COULD VERY WELL SEE TEMPS MAX OUT AT 94-95 IN
SOME LOCATIONS. MOS GUIDANCE LOOKS FAR TOO COOL AND WILL GENERALLY
BE 2-3 DEGREES WARMER. MOS GUIDANCE WITH HIGHS MAINLY IN THE UPPER
80S LOOKED REASONABLE FOR SATURDAY WITH STORMS AND INCREASED CLOUD
COVERAGE. LOWS WILL REMAIN IN THE 70S TONIGHT AND FRIDAY NIGHT...
FALLING BACK INTO THE 60S SATURDAY NIGHT AS COOLER DRIER AIR EXPANDS
SOUTH BEHIND THE FRONT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 305 AM EDT THU JUL 18 2013
TEMPERATURES WILL NOT BE QUITE AS HOT DURING THE LONG TERM AS THE
UPPER HIGH WILL BE OVER THE WESTERN U.S. AND HEIGHTS LOWER A LITTLE
ACROSS THE GREAT LAKES. A WEAK COLD FRONT WILL STALL ACROSS THE
GREAT LAKES SUNDAY AS HIGH PRESSURE MOVES EAST ACROSS THE GREAT
LAKES. ALL AREAS SHOULD REMAIN DRY UNDER THIS SITUATION SUNDAY.
AFTER SUNDAY WILL MENTION CHANCE POPS FROM LATE SUNDAY NIGHT THROUGH
DAY 7 AS A SERIES OF WEAK DISTURBANCES MOVE EAST ALONG THIS STALLED
FRONT. THERE IS SOME DISCREPANCY ON TIMING OF THESE DISTURBANCES
BETWEEN THE DIFFERENT MODELS. HOWEVER MODEL CONSENSUS SEEMS TO POINT
TOWARDS ONE OF THE MAIN DISTURBANCES MOVING THROUGH AROUND MONDAY
AND ANOTHER ONE EITHER MOVING ACROSS OUR REGION TUESDAY NIGHT OR
WEDNESDAY.
CUT ALL BLEND POPS A LITTLE SUNDAY AND SUNDAY EVENING.
OTHERWISE...I DID NOT MAKE ANY SIGNIFICANT CHANGES TO POPS OR
TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR THE 180900Z KIND TAF UPDATE/...
ISSUED AT 427 AM EDT THU JUL 18 2013
MINOR TWEAKS MADE TO KIND TAF TO BETTER MATCH CURRENT CONDITIONS. NO
OTHER CHANGES NEEDED AT THIS TIME. PREVIOUS AVIATION DISCUSSION
FOLLOWS...
ASIDE FROM SOME OVERNIGHT MVFR VSBYS AT LAF/HUF/BMG...VFR CONDITIONS
ARE EXPECTED DURING THIS TAF CYCLE.
CONVECTION THAT OCCURRED OVER FAR SOUTHERN INDIANA AS WELL AS
NORTHERN/CENTRAL KENTUCKY WEDNESDAY EVENING HAS DISSIPATED AND ITS
ASSOCIATED MID/UPPER CLOUD COVER THAT WAS INITIALLY PRESSING
NORTHWARD IS CONTINUING TO ERODE ON THE NORTHERN EDGE.
PERSISTENCE FORECAST CONTINUES AS CONDITIONS REMAIN SIMILAR TO LAST
NIGHT WITH THE UPPER RIDGE OVERHEAD. THUS...FOG FORMATION CONTINUES
TO BE THE MAIN ISSUE. LIGHT WINDS WILL PERSIST OVERNIGHT AS SURFACE
HIGH PRESSURE REMAINS IN CONTROL. COUPLE THAT WITH DEWPOINT
DEPRESSIONS ALREADY LESS THAN OR EQUAL TO 5 DEGREES AT
LAF/HUF/BMG...CANNOT RULE OUT A REPEAT OF LAST NIGHT OR CLOSE TO IT.
THUS...HAVE KEPT THE MVFR CONDITIONS GOING FOR LAF/HUF/BMG
TONIGHT...UNTIL 12/13Z THURSDAY. NO MENTION CURRENTLY OF ANY BRIEF
IFR VSBYS AT LAF/HUF/BMG...BUT WOULD NOT RULE IT OUT BETWEEN 08Z TO
11Z. EXPECT CU TO DEVELOP OVER THE AREA AGAIN LATE TOMORROW MORNING
WITH BASES AOA 4 KFT. WINDS WILL REMAIN UNDER 10 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....JH
AVIATION...MRD/JH
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
346 AM EDT THU JUL 18 2013
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED
BELOW.
&&
.SYNOPSIS...
ISSUED AT 346 AM EDT THU JUL 18 2013
HOT AND HUMID WEATHER WILL CONTINUE THROUGH FRIDAY AS THE RIDGE
ALOFT GRADUALLY SHIFTS TO THE SOUTH. A VIGOROUS UPPER LEVEL LOW WILL
TRACK THROUGH EASTERN CANADA WITH A COLD FRONT TRACKING SOUTH INTO
THE REGION ON SATURDAY. THE ARRIVAL AND PASSAGE OF THE FRONT WILL
BRING NUMEROUS SHOWERS AND THUNDERSTORMS TO CENTRAL INDIANA LATE
FRIDAY NIGHT THROUGH SATURDAY EVENING. COOLER DRIER AIR WILL BRIEFLY
BUILD INTO THE REGION ON SUNDAY AS HIGH PRESSURE PASSES THROUGH THE
GREAT LAKES. CHANCES FOR THUNDERSTORMS WILL RETURN BY LATE SUNDAY
NIGHT AND MONDAY AND CONTINUE THROUGH THE MIDDLE OF NEXT WEEK AS THE
FRONTAL BOUNDARY DRIFTS BACK NORTH INTO THE AREA.
&&
.NEAR TERM /TODAY/...
ISSUED AT 346 AM EDT THU JUL 18 2013
ANOTHER MUGGY START EARLY THIS MORNING AS 07Z TEMPS GENERALLY IN THE
MID AND UPPER 70S. CONVECTIVE DEBRIS CLOUDS CONTINUE TO DRIFT INTO
THE SOUTHERN HALF OF THE FORECAST AREA AS A WEAK UPPER WAVE
CURRENTLY TRACKS ACROSS THE TENNESSEE VALLEY.
THE UPPER LEVEL HIGH REMAINS PARKED ACROSS CENTRAL INDIANA WITH MID
LEVEL HEIGHT MAXES STILL AROUND 597DAM. THESE HEIGHTS WILL SLOWLY
FALL THROUGH THE DAY AS THE RIDGE GRADUALLY BUCKLES IN RESPONSE TO A
DEVELOPING STRONG UPPER LOW GETTING ITS ACT TOGETHER ACROSS JAMES
BAY. THE AFOREMENTIONED WEAK WAVE ALOFT OVER THE TENNESSEE VALLEY
WILL DRIFT WEST THROUGH THE DAY AND SHOULD BE LOCATED OVER THE LOWER
OHIO VALLEY BY LATE DAY. SCATTERED CONVECTION ASSOCIATED WITH THIS
FEATURE SHOULD DEVELOP ACROSS KENTUCKY AND TENNESSEE AND MAY EVEN
SEE A FEW STORMS MAKE IT INTO OUR SOUTHERN COUNTIES. THE HRRR LOOKS
TO BE OVERDOING CONVECTIVE DEVELOPMENT IN GENERAL BUT HINTS AT THIS
IDEA AS WELL. CONSIDERING THE NATURE OF THE AIRMASS AND THE
PROXIMITY OF THE UPPER WAVE...ISOLATED POPS ARE WARRANTED ACROSS FAR
SOUTHERN COUNTIES FOR THIS AFTERNOON. FURTHER NORTH DESPITE THE
GRADUALLY LOWERING MID LEVEL HEIGHTS...THE RIDGING ALOFT AND CAP
NEAR 650MB ARE LIKELY TO REMAIN TOO STRONG FOR ANY SUBSTANTIAL
CONVECTIVE DEVELOPMENT. WHILE AN ISOLATED SHOWER CANNOT BE RULED
OUT...COVERAGE LIKELY TO BE SO LOW TO PRECLUDE ANY MENTION IN THE
FORECAST AT THIS TIME.
TEMPS...LOW LEVEL THERMALS WILL BE SIMILAR TO WEDNESDAY WITH 850MB
TEMPS RISING TO AROUND 19-20C. LIKEWISE EXPECT HIGH TEMPS TO BE
SIMILAR TO WEDNESDAY AS WELL...REACHING THE 92-94 DEGREE RANGE FOR
MUCH OF THE FORECAST AREA. GENERALLY GOING A DEGREE OR TWO ABOVE
MOS. MAX HEAT INDICES WILL RISE TO AROUND 100 DEGREES AGAIN THIS
AFTERNOON...AND MAY TOP OUT JUST A TOUCH WARMER THAN WEDNESDAY AS
SLIGHTLY DEEPER MOISTURE IS PULLED NORTH INTO THE REGION. HAVE NO
PLANS TO INTRODUCE A HEAT ADVISORY AS THESE VALUES REMAINS BELOW
CRITERIA. WILL CONTINUE WITH THE SPS.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 346 AM EDT THU JUL 18 2013
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES AND TEMPS AS A COLD
FRONT DROPS SOUTH THROUGH THE REGION SATURDAY. MODELS GENERALLY IN
VERY GOOD AGREEMENT ON MAIN FEATURES THROUGHOUT THE SHORT TERM.
RIDGING ALOFT WILL CONTINUE TO SINK SOUTH AND FLATTEN AS THE DEEP
UPPER LOW DIVES ACROSS NORTHERN ONTARIO...THEN PINWHEELS INTO THE
CANADIAN MARITIMES BY SUNDAY MORNING. ROBUST CONVECTIVE DEVELOPMENT
WILL TAKE PLACE TONIGHT OVER THE UPPER MISSISSIPPI VALLEY AND
NORTHERN GREAT LAKES IN PROXIMITY TO THE COLD FRONT. THIS FRONT WILL
SINK SOUTH AND SHOULD BE LOCATED ACROSS THE WESTERN GREAT LAKES BY
FRIDAY AFTERNOON. THE FLATTENING OF THE RIDGE AND APPROACH OF THE
COLD FRONT WILL ENCOURAGE A W/SW FLOW THROUGH THE LOWER LEVELS ON
FRIDAY...WITH POTENTIAL FOR SOME GUSTS TO NEAR 20-25KTS OVER
NORTHERN COUNTIES BY AFTERNOON AS A LOW LEVEL JET ACCOMPANIES THE
BOUNDARY THROUGH THE GREAT LAKES. WILL MAINTAIN LOW CHANCE POPS FOR
ISOLATED CONVECTIVE DEVELOPMENT FRIDAY AFTERNOON...BUT ANTICIPATE IT
WILL BE MORE FOCUSED OVER THE SOUTHERN HALF OF THE FORECAST AREA
WHERE DEEPER MOISTURE WILL RESIDE. THE W/SW FLOW WILL DRAW A SLUG OF
DRIER AIR ALOFT INTO THE LOWER GREAT LAKES IMMEDIATELY AHEAD OF THE
FRONT THAT WILL GRADUALLY BECOME SQUEEZED BY MOISTURE ADVECTING NORTH
AROUND THE BACK SIDE OF THE BERMUDA HIGH AND MOISTURE POOLING ALONG
THE BOUNDARY. THIS MAY LIMIT CONVECTIVE DEVELOPMENT OVER NORTHERN
COUNTIES FOR MUCH OF THE DAY.
FOCUS WILL SHIFT TO THE N/NW OF THE REGION BY LATE FRIDAY AFTERNOON
AS CONVECTION IS LIKELY TO DEVELOP IN THE VICINITY OF THE BOUNDARY
AND QUICKLY BECOME SEVERE AS BL SHEAR VALUES ARE ENHANCED AND
AIRMASS WILL BE MODERATELY UNSTABLE. STORMS ARE LIKELY TO ORGANIZE
INTO A MESOSCALE CONVECTIVE COMPLEX BY FRIDAY EVENING WITH
THERMODYNAMIC PROFILES SUGGESTING THE POTENTIAL FOR A SIGNIFICANT
DAMAGING WIND THREAT AS THE STORMS MOVE ACROSS THE LOWER GREAT
LAKES. THIS CONVECTION SHOULD LARGELY REMAIN TO THE NORTH OF THE
FORECAST AREA THROUGH THE EVENING...WITH PRECIP CHANCES RISING AFTER
MIDNIGHT AS THE TAIL END OF THE COMPLEX SAGS SOUTH INTO THE REGION
WITH THE COLD FRONT. AT THIS POINT...THERE IS GREATER UNCERTAINTY AS
TO THE POTENTIAL FOR CONVECTION TO MAINTAIN ITS INTENSITY OVER THE
FORECAST AREA LATE FRIDAY NIGHT. THE CORE OF THE COMPLEX IS EXPECTED
TO TRACK ACROSS THE LOWER GREAT LAKES IN CLOSER PROXIMITY TO THE
DEEPER FORCING ALOFT AND THE LOCATION OF THE LOW LEVEL JET. THE
COMPLEX IS LIKELY TO DROP A WELL DEFINED COLD POOL AND THERE IS A
POSSIBILITY THAT THIS COULD WORK INTO NORTHERN PORTIONS OF THE
FORECAST AREA BEFORE WEAKENING. AT THIS POINT...ANTICIPATE A
WEAKENING LINE OF STORMS IMPACTING THE FORECAST AREA LATE FRIDAY
NIGHT WITH THE POTENTIAL FOR STORMS TO PRODUCE DAMAGING WINDS.
THE FRONT WILL SLOW DOWN ITS FORWARD PROGRESS AS IT RUNS INTO THE
SUPPRESSED RIDGE TO OUR SOUTH. BOUNDARY LIKELY TO TAKE ALL DAY
SATURDAY AND LIKELY A PORTION OF SATURDAY NIGHT TO MOVE ACROSS THE
FORECAST AREA. LEFTOVER CONVECTION FROM FRIDAY NIGHT MAY BE ONGOING
IN A WEAKENED STATE SATURDAY MORNING...BUT EXPECT RENEWED
DEVELOPMENT THROUGHOUT THE DAY. PRECIP WATER VALUES NEAR 2
INCHES...LOW LEVEL CONVERGENCE IN VICINITY OF THE FRONT AND MODEST
INSTABILITY WILL BE THE MAIN CATALYSTS FOR CONVECTIVE DEVELOPMENT
AND INTENSITY AS DEEPER FORCING ALOFT WILL BE FOCUSED FURTHER TO THE
NORTHEAST OVER THE EASTERN GREAT LAKES AND INTO NEW ENGLAND. WHILE
STORMS WILL HAVE THE POTENTIAL TO PRODUCE DAMAGING WINDS...NOT
EXPECTING A WIDESPREAD SEVERE THREAT IN THE ABSENCE OF DEEPER SHEAR
AND BETTER FORCING ALOFT. POTENTIAL FOR HEAVY RAINFALL AND LOCALIZED
FLOODING WITH THE HIGH PWATS. WILL CARRY HIGH CHANCE/LIKELY POPS
SATURDAY...WITH PRECIP CHANCES ENDING LATE SATURDAY NIGHT AS THE
FRONT SETTLES NEAR THE OHIO RIVER.
TEMPS...SEVERAL FACTORS SUGGESTIVE THAT FRIDAY COULD BE THE HOTTEST
DAY OF THIS RECENT STRETCH OF HOT DAYS FOR MUCH OF THE FORECAST AREA.
850MB TEMPS RISE TO 20-21C AND COMBINED WITH THE STRONGER W/SW FLOW
WHICH SHOULD ENHANCE BOUNDARY LAYER MIXING AND COMPRESSIONAL HEATING
AHEAD OF THE FRONT...COULD VERY WELL SEE TEMPS MAX OUT AT 94-95 IN
SOME LOCATIONS. MOS GUIDANCE LOOKS FAR TOO COOL AND WILL GENERALLY
BE 2-3 DEGREES WARMER. MOS GUIDANCE WITH HIGHS MAINLY IN THE UPPER
80S LOOKED REASONABLE FOR SATURDAY WITH STORMS AND INCREASED CLOUD
COVERAGE. LOWS WILL REMAIN IN THE 70S TONIGHT AND FRIDAY NIGHT...
FALLING BACK INTO THE 60S SATURDAY NIGHT AS COOLER DRIER AIR EXPANDS
SOUTH BEHIND THE FRONT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 305 AM EDT THU JUL 18 2013
TEMPERATURES WILL NOT BE QUITE AS HOT DURING THE LONG TERM AS THE
UPPER HIGH WILL BE OVER THE WESTERN U.S. AND HEIGHTS LOWER A LITTLE
ACROSS THE GREAT LAKES. A WEAK COLD FRONT WILL STALL ACROSS THE
GREAT LAKES SUNDAY AS HIGH PRESSURE MOVES EAST ACROSS THE GREAT
LAKES. ALL AREAS SHOULD REMAIN DRY UNDER THIS SITUATION SUNDAY.
AFTER SUNDAY WILL MENTION CHANCE POPS FROM LATE SUNDAY NIGHT THROUGH
DAY 7 AS A SERIES OF WEAK DISTURBANCES MOVE EAST ALONG THIS STALLED
FRONT. THERE IS SOME DISCREPANCY ON TIMING OF THESE DISTURBANCES
BETWEEN THE DIFFERENT MODELS. HOWEVER MODEL CONSENSUS SEEMS TO POINT
TOWARDS ONE OF THE MAIN DISTURBANCES MOVING THROUGH AROUND MONDAY
AND ANOTHER ONE EITHER MOVING ACROSS OUR REGION TUESDAY NIGHT OR
WEDNESDAY.
CUT ALL BLEND POPS A LITTLE SUNDAY AND SUNDAY EVENING.
OTHERWISE...I DID NOT MAKE ANY SIGNIFICANT CHANGES TO POPS OR
TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR THE 180600Z TAF ISSUANCE/...
ISSUED AT 1236 AM EDT THU JUL 18 2013
ASIDE FROM SOME OVERNIGHT MVFR VSBYS AT LAF/HUF/BMG...VFR CONDITIONS
ARE EXPECTED DURING THIS TAF CYCLE.
CONVECTION THAT OCCURRED OVER FAR SOUTHERN INDIANA AS WELL AS
NORTHERN/CENTRAL KENTUCKY WEDNESDAY EVENING HAS DISSIPATED AND ITS
ASSOCIATED MID/UPPER CLOUD COVER THAT WAS INITIALLY PRESSING
NORTHWARD IS CONTINUING TO ERODE ON THE NORTHERN EDGE.
PERSISTENCE FORECAST CONTINUES AS CONDITIONS REMAIN SIMILAR TO LAST
NIGHT WITH THE UPPER RIDGE OVERHEAD. THUS...FOG FORMATION CONTINUES
TO BE THE MAIN ISSUE. LIGHT WINDS WILL PERSIST OVERNIGHT AS SURFACE
HIGH PRESSURE REMAINS IN CONTROL. COUPLE THAT WITH DEWPOINT
DEPRESSIONS ALREADY LESS THAN OR EQUAL TO 5 DEGREES AT
LAF/HUF/BMG...CANNOT RULE OUT A REPEAT OF LAST NIGHT OR CLOSE TO IT.
THUS...HAVE KEPT THE MVFR CONDITIONS GOING FOR LAF/HUF/BMG
TONIGHT...UNTIL 12/13Z THURSDAY. NO MENTION CURRENTLY OF ANY BRIEF
IFR VSBYS AT LAF/HUF/BMG...BUT WOULD NOT RULE IT OUT BETWEEN 08Z TO
11Z. EXPECT CU TO DEVELOP OVER THE AREA AGAIN LATE TOMORROW MORNING
WITH BASES AOA 4 KFT. WINDS WILL REMAIN UNDER 10 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....JH
AVIATION...MRD/JH
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS JACKSON KY
221 PM EDT THU JUL 18 2013
.UPDATE...
ISSUED AT 221 PM EDT THU JUL 18 2013
UPDATED FORECAST GRIDS BASED ON LATEST TRENDS. NO APPRECIABLE CHANGE
OCCURRED TO THE OVERALL FORECAST.
UPDATE ISSUED AT 1105 AM EDT THU JUL 18 2013
SHOWERS/THUNDERSTORMS SO FAR HAVE BEEN TO OUR WEST...AND HAVE UPDATED TO
DELAY THEIR DEVELOPMENT A BIT TODAY. WITH BOTH GFS AND NEW 12Z NAM
SHOWING BEST SHOT AT PRECIP OVER THE HIGHER TERRAIN IN OUR SE THIS
AFTERNOON...HAVE LEFT THE INHERITED 12 HOUR POPS IN PLACE WITH THE
HIGHER VALUES IN THE SE. HOWEVER...THE HRRR IS ALSO SHOWING
DEVELOPMENT OVER OUR WESTERN COUNTIES TODAY. DO NOT HAVE A LOT OF
CONFIDENCE IN THE CONVECTIVE EVOLUTION TODAY. HAVE ALSO TOUCHED UP
OTHER GRIDS BASED ON LATEST OBS. ALL IN ALL...MADE LITTLE CHANGE TO
THE OVERALL AFTERNOON FORECAST.
UPDATE ISSUED AT 710 AM EDT THU JUL 18 2013
FRESHENED UP THE HOURLY TEMPERATURES...DEW POINTS...AND SKY COVER
ACCORDING TO THE LATEST TRENDS IN OBSERVATIONS. OTHERWISE...THE
FORECAST REMAINS ON TRACK.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 355 AM EDT THU JUL 18 2013
THE MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM...GRADUALLY
WEAKENING AND SHIFTING THE OHIO VALLEY UPPER LEVEL RIDGE SOUTHEAST
WITH TIME...AS PASSING UPPER LEVEL DISTURBANCES WITHIN THE NORTHERN
STREAM TRAVERSE THE U.S./CANDAIAN BORDER.
ONE MORE DAY OF HEAT INDICES APPROACHING THE 100 DEGREE MARK IS
EXPECTED...AS HIGHS TOP OUT IN THE LOWER 90S...WHILE DEW POINTS HANG IN
THE LOWER TO MID 70S. CONVECTION WILL THREATEN ONCE AGAIN TODAY AS
THE RIDGE GRADUALLY BREAKS DOWN...ALTHOUGH INSTABILITY LOOKS TO BE
SLIGHTLY WEAKER TODAY COMPARED TO YESTERDAY. THE BLENDED MODEL
GUIDANCE YIELDS SCATTERED COVERAGE TODAY...WITH HIGHER POPS IN THE
SOUTHEAST. THIS SEEMED TO WORK WELL YESTERDAY...SO WILL GO WITH A
SIMILAR SCENARIO...ALTHOUGH WITH WEAK STORM MOTIONS...OUTFLOW
BOUNDARIES COULD SURGE FORWARD FROM ANY DIRECTION AND COULD SPARK NEW
CONVECTION. LOCALLY HEAVY RAINFALL...GUSTY WINDS...AND SMALL HAIL
WITH ACCOMPANY THE STRONGER STORMS.
CONVECTION WILL GRADUALLY DIMINISH THIS EVENING WITH THE LOSS OF
HEATING...AS LOWS ONCE AGAIN ONLY DROP DOWN TO AROUND 70. BY
FRIDAY...THE UPPER LEVEL RIDGE WILL HAVE SHIFTED TO OFF THE
SOUTHEAST COAST. THIS WILL ALLOW FOR MORE CLOUD COVER AND BETTER
CONVECTIVE AREAL COVERAGE ACROSS THE AREA DURING THE AFTERNOON.
AGAIN...LOCALLY HEAVY RAINFALL...GUSTY WINDS...AN SMALL HAIL WILL
ACCOMPANY THE STRONGER STORMS. HEAT INDICES SHOULD BE SLIGHTLY LESS
ON FRIDAY...GENERALLY IN THE MID 90S.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 355 AM EDT THU JUL 18 2013
THERE CONTINUES TO BE GOOD MODEL AGREEMENT THAT THE UPPER LEVEL
RIDGE WILL BE IN THE PROCESS OF BREAKING DOWN AT THE BEGINNING OF
THE LONG TERM FORECAST PERIOD. THIS WEEKEND...A STRONG UPPER LEVEL
LOW WILL BE SWINGING THROUGH EASTERN CANADA...SOLIDIFYING A BROAD
TROUGH ACROSS THE GREAT LAKES AND OHIO VALLEY REGIONS...WHICH SHOULD
THEN PERSIST INTO THE MIDDLE OF NEXT WEEK.
FRIDAY NIGHT AND SATURDAY...A WEAK COLD FRONT WILL BE
APPROACHING FROM THE NORTH. IT APPEARS THE FRONT WILL MAKE ITS WAY
INTO EASTERN KY SUNDAY...BUT WILL LIKELY LINGER ACROSS KY OR
NORTHERN TN INTO THE EARLY TO MIDDLE PART OF NEXT WEEK. WITH
APPROACH OF THE FRONT...THE THREAT FOR MORE ORGANIZED CONVECTION
WILL INCREASE LATE SATURDAY INTO SATURDAY EVENING AND NIGHT AND
LINGER INTO SUNDAY. THE STRONG WINDS ALOFT AND BEST DYNAMICS FROM
THIS SYSTEM WILL PASS BY TO OUR NORTH AND NORTHEAST...SO THE RISK OF
SEVERE THUNDERSTORMS SHOULD REMAIN NORTH OF THE OH RIVER...ALTHOUGH
A FEW STRONG STORMS ARE POSSIBLE SAT AFTERNOON AND EVENING ACROSS
EASTERN KY. ANY STORMS THAT DEVELOP WILL BE RATHER SLOW MOVING AND
WITH THE FRONT STALLING OUT OVER OR NEAR KY...SOME LOCALLY HEAVY
RAIN IS POSSIBLE.
WHILE OVERALL RAIN PROBABILITIES SHOULD DECREASE EARLY NEXT WEEK...A
SERIES OF HARD TO TIME SHORT WAVE TROUGHS MOVING ACROSS THE OH
VALLEY IN THE MEAN FLOW WILL CONTINUE THE THREAT FOR ROUNDS OF
SHOWERS AND THUNDERSTORMS. CONFIDENCE IN TIMING OF THESE CHANCES IS
RATHER LOW...AND A DIURNAL FLAVOR WAS USED IN THE POPS FOR MOST OF
THE PERIOD.
TEMPERATURES SHOULD REMAIN AT OR BELOW NORMAL THROUGH THE PERIOD FOR
DAYTIME HIGHS. HOWEVER...A MOIST AIR MASS WILL REMAIN WITH DEW POINTS
IN THE UPPER 60S TO AROUND 70 SO OVERNIGHT LOWS SHOULD AVERAGE A FEW
DEGREES ABOVE NORMAL THROUGH THE PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 133 PM EDT THU JUL 18 2013
SCATTERED SHOWERS/THUNDERSTORMS WILL OCCUR THIS AFTERNOON.
LOCALIZED IFR WILL OCCUR IN THE THUNDERSTORMS AND HEAVIER SHOWERS.
THE EXTENT OF COVERAGE IS UNCERTAIN...AND THIS WILL ALSO PLAY A ROLE
IN WEATHER FOR TONIGHT. FOG IS EXPECTED TONIGHT...ESPECIALLY IN
VALLEYS. AREAS WHICH RECEIVE RAIN LATE IN THE DAY WILL BE
PARTICULARLY SUSCEPTIBLE TO FOG TONIGHT. HOWEVER...WITH COVERAGE OF
PRECIP TODAY IN QUESTION...WILL BE CONSERVATIVE IN FORECASTING FOG AT
TAF SITES FOR TONIGHT. FOG WILL DISSIPATE BY AROUND 13Z ON FRIDAY.
OUTSIDE OF LOCALIZED SHOWERS/THUNDERSTORMS AND NIGHT TIME FOG...VFR
WITH LIGHT WINDS IS FORECAST.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...GEOGERIAN
LONG TERM...SBH/JP
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS JACKSON KY
133 PM EDT THU JUL 18 2013
.UPDATE...
ISSUED AT 1105 AM EDT THU JUL 18 2013
SHOWERS/THUNDERSTORMS SO FAR HAVE BEEN TO OUR WEST...AND HAVE UPDATED TO
DELAY THEIR DEVELOPMENT A BIT TODAY. WITH BOTH GFS AND NEW 12Z NAM
SHOWING BEST SHOT AT PRECIP OVER THE HIGHER TERRAIN IN OUR SE THIS
AFTERNOON...HAVE LEFT THE INHERITED 12 HOUR POPS IN PLACE WITH THE
HIGHER VALUES IN THE SE. HOWEVER...THE HRRR IS ALSO SHOWING
DEVELOPMENT OVER OUR WESTERN COUNTIES TODAY. DO NOT HAVE A LOT OF
CONFIDENCE IN THE CONVECTIVE EVOLUTION TODAY. HAVE ALSO TOUCHED UP
OTHER GRIDS BASED ON LATEST OBS. ALL IN ALL...MADE LITTLE CHANGE TO
THE OVERALL AFTERNOON FORECAST.
UPDATE ISSUED AT 710 AM EDT THU JUL 18 2013
FRESHENED UP THE HOURLY TEMPERATURES...DEW POINTS...AND SKY COVER
ACCORDING TO THE LATEST TRENDS IN OBSERVATIONS. OTHERWISE...THE
FORECAST REMAINS ON TRACK.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 355 AM EDT THU JUL 18 2013
THE MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM...GRADUALLY
WEAKENING AND SHIFTING THE OHIO VALLEY UPPER LEVEL RIDGE SOUTHEAST
WITH TIME...AS PASSING UPPER LEVEL DISTURBANCES WITHIN THE NORTHERN
STREAM TRAVERSE THE U.S./CANDAIAN BORDER.
ONE MORE DAY OF HEAT INDICES APPROACHING THE 100 DEGREE MARK IS
EXPECTED...AS HIGHS TOP OUT IN THE LOWER 90S...WHILE DEW POINTS HANG IN
THE LOWER TO MID 70S. CONVECTION WILL THREATEN ONCE AGAIN TODAY AS
THE RIDGE GRADUALLY BREAKS DOWN...ALTHOUGH INSTABILITY LOOKS TO BE
SLIGHTLY WEAKER TODAY COMPARED TO YESTERDAY. THE BLENDED MODEL
GUIDANCE YIELDS SCATTERED COVERAGE TODAY...WITH HIGHER POPS IN THE
SOUTHEAST. THIS SEEMED TO WORK WELL YESTERDAY...SO WILL GO WITH A
SIMILAR SCENARIO...ALTHOUGH WITH WEAK STORM MOTIONS...OUTFLOW
BOUNDARIES COULD SURGE FORWARD FROM ANY DIRECTION AND COULD SPARK NEW
CONVECTION. LOCALLY HEAVY RAINFALL...GUSTY WINDS...AND SMALL HAIL
WITH ACCOMPANY THE STRONGER STORMS.
CONVECTION WILL GRADUALLY DIMINISH THIS EVENING WITH THE LOSS OF
HEATING...AS LOWS ONCE AGAIN ONLY DROP DOWN TO AROUND 70. BY
FRIDAY...THE UPPER LEVEL RIDGE WILL HAVE SHIFTED TO OFF THE
SOUTHEAST COAST. THIS WILL ALLOW FOR MORE CLOUD COVER AND BETTER
CONVECTIVE AREAL COVERAGE ACROSS THE AREA DURING THE AFTERNOON.
AGAIN...LOCALLY HEAVY RAINFALL...GUSTY WINDS...AN SMALL HAIL WILL
ACCOMPANY THE STRONGER STORMS. HEAT INDICES SHOULD BE SLIGHTLY LESS
ON FRIDAY...GENERALLY IN THE MID 90S.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 355 AM EDT THU JUL 18 2013
THERE CONTINUES TO BE GOOD MODEL AGREEMENT THAT THE UPPER LEVEL
RIDGE WILL BE IN THE PROCESS OF BREAKING DOWN AT THE BEGINNING OF
THE LONG TERM FORECAST PERIOD. THIS WEEKEND...A STRONG UPPER LEVEL
LOW WILL BE SWINGING THROUGH EASTERN CANADA...SOLIDIFYING A BROAD
TROUGH ACROSS THE GREAT LAKES AND OHIO VALLEY REGIONS...WHICH SHOULD
THEN PERSIST INTO THE MIDDLE OF NEXT WEEK.
FRIDAY NIGHT AND SATURDAY...A WEAK COLD FRONT WILL BE
APPROACHING FROM THE NORTH. IT APPEARS THE FRONT WILL MAKE ITS WAY
INTO EASTERN KY SUNDAY...BUT WILL LIKELY LINGER ACROSS KY OR
NORTHERN TN INTO THE EARLY TO MIDDLE PART OF NEXT WEEK. WITH
APPROACH OF THE FRONT...THE THREAT FOR MORE ORGANIZED CONVECTION
WILL INCREASE LATE SATURDAY INTO SATURDAY EVENING AND NIGHT AND
LINGER INTO SUNDAY. THE STRONG WINDS ALOFT AND BEST DYNAMICS FROM
THIS SYSTEM WILL PASS BY TO OUR NORTH AND NORTHEAST...SO THE RISK OF
SEVERE THUNDERSTORMS SHOULD REMAIN NORTH OF THE OH RIVER...ALTHOUGH
A FEW STRONG STORMS ARE POSSIBLE SAT AFTERNOON AND EVENING ACROSS
EASTERN KY. ANY STORMS THAT DEVELOP WILL BE RATHER SLOW MOVING AND
WITH THE FRONT STALLING OUT OVER OR NEAR KY...SOME LOCALLY HEAVY
RAIN IS POSSIBLE.
WHILE OVERALL RAIN PROBABILITIES SHOULD DECREASE EARLY NEXT WEEK...A
SERIES OF HARD TO TIME SHORT WAVE TROUGHS MOVING ACROSS THE OH
VALLEY IN THE MEAN FLOW WILL CONTINUE THE THREAT FOR ROUNDS OF
SHOWERS AND THUNDERSTORMS. CONFIDENCE IN TIMING OF THESE CHANCES IS
RATHER LOW...AND A DIURNAL FLAVOR WAS USED IN THE POPS FOR MOST OF
THE PERIOD.
TEMPERATURES SHOULD REMAIN AT OR BELOW NORMAL THROUGH THE PERIOD FOR
DAYTIME HIGHS. HOWEVER...A MOIST AIR MASS WILL REMAIN WITH DEW POINTS
IN THE UPPER 60S TO AROUND 70 SO OVERNIGHT LOWS SHOULD AVERAGE A FEW
DEGREES ABOVE NORMAL THROUGH THE PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 133 PM EDT THU JUL 18 2013
SCATTERED SHOWERS/THUNDERSTORMS WILL OCCUR THIS AFTERNOON.
LOCALIZED IFR WILL OCCUR IN THE THUNDERSTORMS AND HEAVIER SHOWERS.
THE EXTENT OF COVERAGE IS UNCERTAIN...AND THIS WILL ALSO PLAY A ROLE
IN WEATHER FOR TONIGHT. FOG IS EXPECTED TONIGHT...ESPECIALLY IN
VALLEYS. AREAS WHICH RECEIVE RAIN LATE IN THE DAY WILL BE
PARTICULARLY SUSCEPTIBLE TO FOG TONIGHT. HOWEVER...WITH COVERAGE OF
PRECIP TODAY IN QUESTION...WILL BE CONSERVATIVE IN FORECASTING FOG AT
TAF SITES FOR TONIGHT. FOG WILL DISSIPATE BY AROUND 13Z ON FRIDAY.
OUTSIDE OF LOCALIZED SHOWERS/THUNDERSTORMS AND NIGHT TIME FOG...VFR
WITH LIGHT WINDS IS FORECAST.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...GEOGERIAN
LONG TERM...SBH/JP
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS JACKSON KY
1105 AM EDT THU JUL 18 2013
.UPDATE...
ISSUED AT 1105 AM EDT THU JUL 18 2013
SHOWERS/THUNDERSTORMS SO FAR HAVE BEEN TO OUR WEST...AND HAVE UPDATED TO
DELAY THEIR DEVELOPMENT A BIT TODAY. WITH BOTH GFS AND NEW 12Z NAM
SHOWING BEST SHOT AT PRECIP OVER THE HIGHER TERRAIN IN OUR SE THIS
AFTERNOON...HAVE LEFT THE INHERITED 12 HOUR POPS IN PLACE WITH THE
HIGHER VALUES IN THE SE. HOWEVER...THE HRRR IS ALSO SHOWING
DEVELOPMENT OVER OUR WESTERN COUNTIES TODAY. DO NOT HAVE A LOT OF
CONFIDENCE IN THE CONVECTIVE EVOLUTION TODAY. HAVE ALSO TOUCHED UP
OTHER GRIDS BASED ON LATEST OBS. ALL IN ALL...MADE LITTLE CHANGE TO
THE OVERALL AFTERNOON FORECAST.
UPDATE ISSUED AT 710 AM EDT THU JUL 18 2013
FRESHENED UP THE HOURLY TEMPERATURES...DEW POINTS...AND SKY COVER
ACCORDING TO THE LATEST TRENDS IN OBSERVATIONS. OTHERWISE...THE
FORECAST REMAINS ON TRACK.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 355 AM EDT THU JUL 18 2013
THE MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM...GRADUALLY
WEAKENING AND SHIFTING THE OHIO VALLEY UPPER LEVEL RIDGE SOUTHEAST
WITH TIME...AS PASSING UPPER LEVEL DISTURBANCES WITHIN THE NORTHERN
STREAM TRAVERSE THE U.S./CANDAIAN BORDER.
ONE MORE DAY OF HEAT INDICES APPROACHING THE 100 DEGREE MARK IS
EXPECTED...AS HIGHS TOP OUT IN THE LOWER 90S...WHILE DEW POINTS HANG IN
THE LOWER TO MID 70S. CONVECTION WILL THREATEN ONCE AGAIN TODAY AS
THE RIDGE GRADUALLY BREAKS DOWN...ALTHOUGH INSTABILITY LOOKS TO BE
SLIGHTLY WEAKER TODAY COMPARED TO YESTERDAY. THE BLENDED MODEL
GUIDANCE YIELDS SCATTERED COVERAGE TODAY...WITH HIGHER POPS IN THE
SOUTHEAST. THIS SEEMED TO WORK WELL YESTERDAY...SO WILL GO WITH A
SIMILAR SCENARIO...ALTHOUGH WITH WEAK STORM MOTIONS...OUTFLOW
BOUNDARIES COULD SURGE FORWARD FROM ANY DIRECTION AND COULD SPARK NEW
CONVECTION. LOCALLY HEAVY RAINFALL...GUSTY WINDS...AND SMALL HAIL
WITH ACCOMPANY THE STRONGER STORMS.
CONVECTION WILL GRADUALLY DIMINISH THIS EVENING WITH THE LOSS OF
HEATING...AS LOWS ONCE AGAIN ONLY DROP DOWN TO AROUND 70. BY
FRIDAY...THE UPPER LEVEL RIDGE WILL HAVE SHIFTED TO OFF THE
SOUTHEAST COAST. THIS WILL ALLOW FOR MORE CLOUD COVER AND BETTER
CONVECTIVE AREAL COVERAGE ACROSS THE AREA DURING THE AFTERNOON.
AGAIN...LOCALLY HEAVY RAINFALL...GUSTY WINDS...AN SMALL HAIL WILL
ACCOMPANY THE STRONGER STORMS. HEAT INDICES SHOULD BE SLIGHTLY LESS
ON FRIDAY...GENERALLY IN THE MID 90S.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 355 AM EDT THU JUL 18 2013
THERE CONTINUES TO BE GOOD MODEL AGREEMENT THAT THE UPPER LEVEL
RIDGE WILL BE IN THE PROCESS OF BREAKING DOWN AT THE BEGINNING OF
THE LONG TERM FORECAST PERIOD. THIS WEEKEND...A STRONG UPPER LEVEL
LOW WILL BE SWINGING THROUGH EASTERN CANADA...SOLIDIFYING A BROAD
TROUGH ACROSS THE GREAT LAKES AND OHIO VALLEY REGIONS...WHICH SHOULD
THEN PERSIST INTO THE MIDDLE OF NEXT WEEK.
FRIDAY NIGHT AND SATURDAY...A WEAK COLD FRONT WILL BE
APPROACHING FROM THE NORTH. IT APPEARS THE FRONT WILL MAKE ITS WAY
INTO EASTERN KY SUNDAY...BUT WILL LIKELY LINGER ACROSS KY OR
NORTHERN TN INTO THE EARLY TO MIDDLE PART OF NEXT WEEK. WITH
APPROACH OF THE FRONT...THE THREAT FOR MORE ORGANIZED CONVECTION
WILL INCREASE LATE SATURDAY INTO SATURDAY EVENING AND NIGHT AND
LINGER INTO SUNDAY. THE STRONG WINDS ALOFT AND BEST DYNAMICS FROM
THIS SYSTEM WILL PASS BY TO OUR NORTH AND NORTHEAST...SO THE RISK OF
SEVERE THUNDERSTORMS SHOULD REMAIN NORTH OF THE OH RIVER...ALTHOUGH
A FEW STRONG STORMS ARE POSSIBLE SAT AFTERNOON AND EVENING ACROSS
EASTERN KY. ANY STORMS THAT DEVELOP WILL BE RATHER SLOW MOVING AND
WITH THE FRONT STALLING OUT OVER OR NEAR KY...SOME LOCALLY HEAVY
RAIN IS POSSIBLE.
WHILE OVERALL RAIN PROBABILITIES SHOULD DECREASE EARLY NEXT WEEK...A
SERIES OF HARD TO TIME SHORT WAVE TROUGHS MOVING ACROSS THE OH
VALLEY IN THE MEAN FLOW WILL CONTINUE THE THREAT FOR ROUNDS OF
SHOWERS AND THUNDERSTORMS. CONFIDENCE IN TIMING OF THESE CHANCES IS
RATHER LOW...AND A DIURNAL FLAVOR WAS USED IN THE POPS FOR MOST OF
THE PERIOD.
TEMPERATURES SHOULD REMAIN AT OR BELOW NORMAL THROUGH THE PERIOD FOR
DAYTIME HIGHS. HOWEVER...A MOIST AIR MASS WILL REMAIN WITH DEW POINTS
IN THE UPPER 60S TO AROUND 70 SO OVERNIGHT LOWS SHOULD AVERAGE A FEW
DEGREES ABOVE NORMAL THROUGH THE PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 710 AM EDT THU JUL 18 2013
THE FOG WILL BURN OFF THROUGH 13Z...WITH SCATTERED CONVECTION
THREATENING ONCE AGAIN FROM 15Z ONWARD. WILL CARRY A VCTS AT ALL
SITES THROUGH ABOUT 5Z...BEFORE MVFR OR WORSE FOG SETS UP ONCE AGAIN.
WINDS WILL REMAIN LIGHT AND VARIABLE THROUGH THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...GEOGERIAN
LONG TERM...SBH/JP
AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION
NWS GRAY ME
617 PM EDT THU JUL 18 2013
.SYNOPSIS...
VERY HOT AND HUMID AIR MOVES IN FOR FRIDAY INTO SATURDAY. A COLD
FRONT WILL WILL CROSS THE REGION SATURDAY...SETTING OFF SHOWERS
AND THUNDERSTORMS...AND SOME OF THOSE STORMS COULD BE SEVERE.
COOLER AND LESS HUMID HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT
SUNDAY THOUGH TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
WILL UPDATE TO INPUT LATEST OBSERVED DATA. HAVE INCREASED THE
CHANCE OF SHOWERS AND THUNDERSTORMS THIS EVENING BASED ON THE
LATEST RADAR. WILL MENTION GUSTY WINDS AND HEAVY RAIN POSSIBLE
WITH SOME THUNDERSTORMS THIS EVENING.
PREVIOUS DISCUSSION...
RELIED HEAVILY ON THE HRRR MODEL FOR THE FORECAST TONIGHT AS THIS
MODEL HAS HANDLED THINGS VERY WELL THE PAST FEW DAYS AND SEEMS TO
BE DOING SO ONCE AGAIN TODAY. CONVECTION HAS FIRED ON THE SEA
BREEZE BOUNDARY IN MAINE... WITH ACTIVITY TENDING TO FALL APART
AFTER IT ADVECTS INTO THE COOLER MARINE AIR. ADDITIONAL ISOLATED
STORMS HAVE DEVELOPED OVER THE HIGHER TERRAIN IN NEW HAMPSHIRE. A
LARGER AREA OF STORMS DEVELOPED OVER THE ADIRONDACKS OF UPSTATE
NEW YORK AND WILL CONTINUE TO PUSH EASTWARD THROUGH VERMONT AND
INTO NEW HAMPSHIRE THIS AFTERNOON. WIND SHEAR IS SUFFICIENT FOR
SUPERCELLS... AND ALREADY A FEW HAVE BEEN OBSERVED. DAMAGING WINDS
AND HAIL WOULD BE THE THREATS FROM STORMS TODAY... ALTHOUGH HEAVY
RAIN WILL ALSO OCCUR. MODERATE STORM MOTIONS SHOULD LIMIT THE
FLASH FLOODING THREAT. EXPECT MOST OF THE ACTIVITY THIS EVENING TO
DIE DOWN AND MOVE OFF TO THE EAST BY AROUND MIDNIGHT. TEMPERATURES
TONIGHT WILL BE WARM... WITH LOWS IN THE UPPER 60S AND LOW 70S.
FOG WILL BE POSSIBLE IN THE CONNECTICUT RIVER VALLEY.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
HOT AND HUMID AIR OVER THE MID ATLANTIC STATES TODAY... EVIDENCED
BY A BROAD AREA OF +20 C TEMPERATURES AT 850 MB... WILL BE
ADVECTED NORTHEAST AND INTO NEW ENGLAND ON FRIDAY. GFS AND NAM IN
GOOD AGREEMENT ON 850 MB TEMPERATURES OF +21 C BY FRIDAY AFTERNOON
OVER THE SOUTHERN HALF OF THE FORECAST AREA. IN ADDITION...
SOUTHWEST FLOW WILL TRANSPORT HIGH DEW POINTS INTO THE AREA.
EXPECT THE DAY TO START OFF WITH LOW 70S DEW POINTS OVER MUCH OF
THE REGION. BUT A SURFACE TROUGH WILL PUSH EASTWARD ACROSS THE
AREA... SHIFTING WINDS FROM THE SOUTH TO THE WEST-SOUTHWEST. THIS
WEST TO SOUTHWEST WIND WILL HAVE A SIGNIFICANT DOWNSLOPING
COMPONENT TO IT... ALLOWING FOR GREATER MIXING. THIS MEANS THREE
THINGS... HIGHER TEMPERATURES... LOWER DEW POINTS... AND GREATER
WIND SPEEDS. AFTERNOON SOUNDINGS INDICATE THAT AS PEAK HEATING
OCCURS... DEW POINTS WILL FALL INTO THE MID 60S BEHIND THE SURFACE
TROUGH. WITH DOWNSLOPING CONDITIONS... THE HOTTEST TEMPERATURES
WILL OCCUR AT LOWER ELEVATIONS WHICH IN THIS CASE MEANS THE COAST.
IT DOES NOT LOOK LIKE THE SEA BREEZE WILL BE MUCH HELP OVER NEW
HAMPSHIRE AND SOUTHWEST MAINE ON FRIDAY AS SOUTHWEST WINDS KEEP
THE SEA BREEZE OFFSHORE. TEMPERATURES ARE EXPECTED TO RISE INTO
THE UPPER 90S TO NEAR 100 DEGREES OVER ROCKINGHAM AND YORK
COUNTIES. RECORD HIGH TEMPERATURES IN CONCORD (98) AND PORTLAND
(94) ARE IN DANGER OF BEING BROKEN.
TIME FOR A BRIEF LESSON ON THE HEAT INDEX. THE HEAT INDEX WAS
DEVELOPED AS A WAY TO APPROXIMATE THE "FEELS LIKE" TEMPERATURE. IT
COMBINES THE EFFECTS OF HEAT AND HUMIDITY TO COME UP WITH THE HEAT
INDEX VALUE. THE CALCULATION MAKES SOME ASSUMPTIONS THAT ARE OFTEN
THE CASE IN THE MOST OPPRESSIVELY HOT AND HUMID AIR MASSES...
ESPECIALLY THOSE THAT OCCUR FREQUENTLY IN THE SOUTH. HOWEVER...
THESE ASSUMPTIONS ARE NOT ALWAYS PRESENT. SOME OF THE ASSUMPTIONS
INVOLVED INCLUDE A RELATIVE HUMIDITY OF AT LEAST 40 PERCENT AND
LIGHT WIND SPEEDS. IN A HUMID ENVIRONMENT... THE BODY`S NORMAL WAY
OF COOLING ITSELF THROUGH SWEAT IS HAMPERED AS THE SWEAT DOES NOT
EVAPORATE OFF THE SKIN QUICKLY ENOUGH. HOWEVER... WITH RELATIVE
HUMIDITY BELOW 40 PERCENT... THE HUMIDITY DOES NOT HAVE AS GREAT
OF AN EFFECT ON THE BODY. ALSO... IF WINDS ARE STRONGER THE SWEAT
IS ABLE TO EVAPORATE BETTER DUE TO BETTER AIR FLOW NEAR THE SKIN
SURFACE. FOR FRIDAY IN NORTHERN NEW ENGLAND... ONE OR BOTH OF
THESE ASSUMPTIONS WILL FAIL. FORECAST RELATIVE HUMIDITY FALLS
BELOW 40 PERCENT DURING THE PEAK HEAT OF THE AFTERNOON AND WINDS
WILL BE GUSTING TO 25 MPH. BOTH OF THESE FACTORS WILL ACT TO
LIMIT THE ACTUAL EFFECT OF THE HEAT AND HUMIDITY... THOUGH HEAT
INDEX VALUES WILL BE VERY HIGH. THIS DOES NOT RENDER THE HEAT
INDEX MEANINGLESS... BUT INDICATES THAT THESE FACTORS MAY
PROVIDE SOME SLIGHT RELIEF FROM WHAT CONDITIONS OTHERWISE COULD
BE.
IN SPITE OF ANY LIMITATIONS INVOLVED IN THE HEAT INDEX... THE HEAT
AND HUMIDITY IS GOING TO FEEL OPPRESSIVE ON FRIDAY ESPECIALLY BY
NORTHERN NEW ENGLAND STANDARDS. HEAT INDEX VALUES ARE FORECAST TO
RISE ABOVE 100 DEGREES FOR SOUTHEAST NEW HAMPSHIRE AND SOUTHWEST
MAINE. A HEAT ADVISORY HAS BEEN ISSUED TO DRAW ATTENTION TO THIS
THREAT AND ALERT PEOPLE TO THE THREATS CAUSED BY THE HIGH HEAT AND
HUMIDITY. IT IS POSSIBLE THAT HEAT INDEX VALUES MAY RISE TO 105
DEGREES OR HIGHER OVER ROCKINGHAM... STRAFFORD... AND YORK
COUNTIES. IF IT DOES SO... THIS WILL TECHNICALLY REACH EXCESSIVE
HEAT WARNING CRITERIA FOR NORTHERN NEW ENGLAND. IT WAS DECIDED NOT
TO ISSUE AN EXCESSIVE HEAT WARNING AT THIS TIME DUE TO THE
UNCERTAINTY REGARDING MAXIMUM TEMPERATURES ACTUALLY REACHING THE
EXTREME VALUES FORECAST AND THE POSSIBILITY OF LOWER DEW POINTS
AND GUSTY WINDS IN THE AFTERNOON. LATER FORECAST SHIFTS MAY FEEL
THE NEED TO UPGRADE TO A WARNING FOR PORTIONS OF THE ADVISORY AREA
IF THE CURRENT FORECAST HOLDS TRUE. THOSE WITH OUTDOOR ACTIVITIES
PLANNED... AND THOSE WITHOUT ACCESS TO AIR CONDITIONING WILL BE
PARTICULARLY VULNERABLE TO THE HEAT.
WITH THE HEAT AND HUMIDITY IN PLACE... THERE WILL ALSO BE PLENTY
OF INSTABILITY AVAILABLE FOR AFTERNOON THUNDERSTORMS. THIS APPEARS
MOST LIKELY IN NORTHERN AREAS. MODERATE TO STRONG MID/UPPER LEVEL
WINDS SUGGEST THAT ORGANIZED THUNDERSTORMS ARE POSSIBLE... AND
THUS SEVERE THUNDERSTORMS MAY OCCUR. HEAVY RAINFALL WILL ALSO BE A
THREAT DUE TO THE HUMID AIR IN PLACE.
TEMPERATURES WILL NOT COOL DOWN MUCH FRIDAY NIGHT AS HIGH HUMIDITY
AND SOME CLOUD COVER KEEP TEMPERATURES IN THE 70S AT NIGHT FOR
MOST AREAS. THIS WILL MAKE IT DIFFICULT FOR HOT BUILDINGS WITHOUT
AIR CONDITIONING TO COOL DOWN AT NIGHT.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
MAIN FOCUS OF THE EXTENDED FORECAST WILL BE SATURDAY AS SURFACE COLD
FRONT DROPS SOUTH INTO HOT AND VERY HUMID AIR MASS. DECENT HEIGHT
FALLS WILL BE ACCOMPANIED BY MODERATE TO STRONG MID-LEVEL
WINDS...ABOVE HIGHLY UNSTABLE SURFACE AIR. THIS WILL SET THE STAGE
FOR GOOD POTENTIAL FOR SEVERE WEATHER ON SATURDAY...ESPECIALLY IN
THE FORM OF DAMAGING WINDS. ONE LIMITING FACTOR COULD BE TIMING
OF PASSAGE OF PRE-FRONTAL TROUGH AND SUBSEQUENT COLD FRONT...WHICH
MAY CAUSE BEST CONVECTIVE FORCING TO OCCUR TOO EARLY.
HOWEVER...GIVEN WARM AND HUMID FRIDAY NIGHT...COULD SEE SEVERE
WEATHER AS EARLY AS LATE MORNING. THE SCATTERED THUNDERSTORMS WILL
LIKELY CONTINUE INTO EARLY EVENING...BUT SHOULD END QUICKLY
AFTER THAT...WITH COOLER AND AND LESS HUMID BEGINNING TO SPILL
INTO THE CWA BEFORE DAYBREAK SUNDAY.
THE COOLER AND LESS HUMID HIGH PRESSURE WILL REMAIN OVER THE CWA
INTO TUESDAY. THE NEXT CHANCE OF RAIN WILL BE LATE TUESDAY INTO
WEDNESDAY AS A WARM FRONT PUSHES NE INTO NEW ENGLAND.
&&
.AVIATION /22Z THURSDAY THROUGH TUESDAY/...
SHORT TERM /THROUGH FRIDAY NIGHT/...VFR EXPECTED THROUGH FRIDAY
NIGHT...EXCEPT FOR AFTERNOON/EVENING THUNDERSTORMS POSSIBLE AT
ALL TAF SITES AND LATE NIGHT FOG MAINLY AT LEB AND HIE WHICH COULD
LOWER CIG/VSBY.
LONG TERM...STRONG THUNDERSTORMS WITH HEAVY RAIN AND GUSTY WINDS
ARE LIKELY AT TIMES ON SAT INTO SAT EVENING. OTHERWISE EXPECT MAINLY
VFR THROUGH TUE.
&&
.MARINE...
SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...WILL UPDATE TO INPUT
LATEST OBSERVED DATA RESULTING IN NO MORE THAN A FEW TWEAKS TO THE
PREVIOUS FORECAST. SOUTHWEST WINDS WILL INCREASE ON FRIDAY AND MAY
SEE A FEW GUSTS APPROACH SCA LEVELS. WAVE HEIGHTS WILL INCREASE
AND MAY RISE TO AROUND THE 5 FT THRESHOLD FOR AN SCA FRIDAY
AFTERNOON INTO FRIDAY NIGHT OVER THE OPEN WATERS.
LONG TERM...BORDERLINE SCA ON SATURDAY WITH SEAS TO AROUND 5 FT...
AND SW WINDS APPROACHING 25 KTS. WINDS SHIFT TO NW SATURDAY NIGHT
AND WEAKEN. THE WATERS REMAIN GENERALLY QUIET SUNDAY THRU TUESDAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...HEAT ADVISORY FROM 10 AM TO 7 PM EDT FRIDAY FOR MEZ012-018>021-
023-024.
NH...HEAT ADVISORY FROM 10 AM TO 7 PM EDT FRIDAY FOR NHZ006-008>010-
013-014.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
420 PM EDT THU JUL 18 2013
.SYNOPSIS...
VERY HOT AND HUMID AIR MOVES IN FOR FRIDAY INTO SATURDAY. A COLD
FRONT WILL WILL CROSS THE REGION SATURDAY...SETTING OFF SHOWERS
AND THUNDERSTORMS...AND SOME OF THOSE STORMS COULD BE SEVERE.
COOLER AND LESS HUMID HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT
SUNDAY THOUGH TUESDAY.
&&
.NEAR TERM /TONIGHT/...
RELIED HEAVILY ON THE HRRR MODEL FOR THE FORECAST TONIGHT AS THIS
MODEL HAS HANDLED THINGS VERY WELL THE PAST FEW DAYS AND SEEMS TO
BE DOING SO ONCE AGAIN TODAY. CONVECTION HAS FIRED ON THE SEA
BREEZE BOUNDARY IN MAINE... WITH ACTIVITY TENDING TO FALL APART
AFTER IT ADVECTS INTO THE COOLER MARINE AIR. ADDITIONAL ISOLATED
STORMS HAVE DEVELOPED OVER THE HIGHER TERRAIN IN NEW HAMPSHIRE. A
LARGER AREA OF STORMS DEVELOPED OVER THE ADIRONDACKS OF UPSTATE
NEW YORK AND WILL CONTINUE TO PUSH EASTWARD THROUGH VERMONT AND
INTO NEW HAMPSHIRE THIS AFTERNOON. WIND SHEAR IS SUFFICIENT FOR
SUPERCELLS... AND ALREADY A FEW HAVE BEEN OBSERVED. DAMAGING WINDS
AND HAIL WOULD BE THE THREATS FROM STORMS TODAY... ALTHOUGH HEAVY
RAIN WILL ALSO OCCUR. MODERATE STORM MOTIONS SHOULD LIMIT THE
FLASH FLOODING THREAT. EXPECT MOST OF THE ACTIVITY THIS EVENING TO
DIE DOWN AND MOVE OFF TO THE EAST BY AROUND MIDNIGHT. TEMPERATURES
TONIGHT WILL BE WARM... WITH LOWS IN THE UPPER 60S AND LOW 70S.
FOG WILL BE POSSIBLE IN THE CONNECTICUT RIVER VALLEY.
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
HOT AND HUMID AIR OVER THE MID ATLANTIC STATES TODAY... EVIDENCED
BY A BROAD AREA OF +20 C TEMPERATURES AT 850 MB... WILL BE
ADVECTED NORTHEAST AND INTO NEW ENGLAND ON FRIDAY. GFS AND NAM IN
GOOD AGREEMENT ON 850 MB TEMPERATURES OF +21 C BY FRIDAY AFTERNOON
OVER THE SOUTHERN HALF OF THE FORECAST AREA. IN ADDITION...
SOUTHWEST FLOW WILL TRANSPORT HIGH DEW POINTS INTO THE AREA.
EXPECT THE DAY TO START OFF WITH LOW 70S DEW POINTS OVER MUCH OF
THE REGION. BUT A SURFACE TROUGH WILL PUSH EASTWARD ACROSS THE
AREA... SHIFTING WINDS FROM THE SOUTH TO THE WEST-SOUTHWEST. THIS
WEST TO SOUTHWEST WIND WILL HAVE A SIGNIFICANT DOWNSLOPING
COMPONENT TO IT... ALLOWING FOR GREATER MIXING. THIS MEANS THREE
THINGS... HIGHER TEMPERATURES... LOWER DEW POINTS... AND GREATER
WIND SPEEDS. AFTERNOON SOUNDINGS INDICATE THAT AS PEAK HEATING
OCCURS... DEW POINTS WILL FALL INTO THE MID 60S BEHIND THE SURFACE
TROUGH. WITH DOWNSLOPING CONDITIONS... THE HOTTEST TEMPERATURES
WILL OCCUR AT LOWER ELEVATIONS WHICH IN THIS CASE MEANS THE COAST.
IT DOES NOT LOOK LIKE THE SEA BREEZE WILL BE MUCH HELP OVER NEW
HAMPSHIRE AND SOUTHWEST MAINE ON FRIDAY AS SOUTHWEST WINDS KEEP
THE SEA BREEZE OFFSHORE. TEMPERATURES ARE EXPECTED TO RISE INTO
THE UPPER 90S TO NEAR 100 DEGREES OVER ROCKINGHAM AND YORK
COUNTIES. RECORD HIGH TEMPERATURES IN CONCORD (98) AND PORTLAND
(94) ARE IN DANGER OF BEING BROKEN.
TIME FOR A BRIEF LESSON ON THE HEAT INDEX. THE HEAT INDEX WAS
DEVELOPED AS A WAY TO APPROXIMATE THE "FEELS LIKE" TEMPERATURE. IT
COMBINES THE EFFECTS OF HEAT AND HUMIDITY TO COME UP WITH THE HEAT
INDEX VALUE. THE CALCULATION MAKES SOME ASSUMPTIONS THAT ARE OFTEN
THE CASE IN THE MOST OPPRESSIVELY HOT AND HUMID AIR MASSES...
ESPECIALLY THOSE THAT OCCUR FREQUENTLY IN THE SOUTH. HOWEVER...
THESE ASSUMPTIONS ARE NOT ALWAYS PRESENT. SOME OF THE ASSUMPTIONS
INVOLVED INCLUDE A RELATIVE HUMIDITY OF AT LEAST 40 PERCENT AND
LIGHT WIND SPEEDS. IN A HUMID ENVIRONMENT... THE BODY`S NORMAL WAY
OF COOLING ITSELF THROUGH SWEAT IS HAMPERED AS THE SWEAT DOES NOT
EVAPORATE OFF THE SKIN QUICKLY ENOUGH. HOWEVER... WITH RELATIVE
HUMIDITY BELOW 40 PERCENT... THE HUMIDITY DOES NOT HAVE AS GREAT
OF AN EFFECT ON THE BODY. ALSO... IF WINDS ARE STRONGER THE SWEAT
IS ABLE TO EVAPORATE BETTER DUE TO BETTER AIR FLOW NEAR THE SKIN
SURFACE. FOR FRIDAY IN NORTHERN NEW ENGLAND... ONE OR BOTH OF
THESE ASSUMPTIONS WILL FAIL. FORECAST RELATIVE HUMIDITY FALLS
BELOW 40 PERCENT DURING THE PEAK HEAT OF THE AFTERNOON AND WINDS
WILL BE GUSTING TO 25 MPH. BOTH OF THESE FACTORS WILL ACT TO
LIMIT THE ACTUAL EFFECT OF THE HEAT AND HUMIDITY... THOUGH HEAT
INDEX VALUES WILL BE VERY HIGH. THIS DOES NOT RENDER THE HEAT
INDEX MEANINGLESS... BUT INDICATES THAT THESE FACTORS MAY
PROVIDE SOME SLIGHT RELIEF FROM WHAT CONDITIONS OTHERWISE COULD
BE.
IN SPITE OF ANY LIMITATIONS INVOLVED IN THE HEAT INDEX... THE HEAT
AND HUMIDITY IS GOING TO FEEL OPPRESSIVE ON FRIDAY ESPECIALLY BY
NORTHERN NEW ENGLAND STANDARDS. HEAT INDEX VALUES ARE FORECAST TO
RISE ABOVE 100 DEGREES FOR SOUTHEAST NEW HAMPSHIRE AND SOUTHWEST
MAINE. A HEAT ADVISORY HAS BEEN ISSUED TO DRAW ATTENTION TO THIS
THREAT AND ALERT PEOPLE TO THE THREATS CAUSED BY THE HIGH HEAT AND
HUMIDITY. IT IS POSSIBLE THAT HEAT INDEX VALUES MAY RISE TO 105
DEGREES OR HIGHER OVER ROCKINGHAM... STRAFFORD... AND YORK
COUNTIES. IF IT DOES SO... THIS WILL TECHNICALLY REACH EXCESSIVE
HEAT WARNING CRITERIA FOR NORTHERN NEW ENGLAND. IT WAS DECIDED NOT
TO ISSUE AN EXCESSIVE HEAT WARNING AT THIS TIME DUE TO THE
UNCERTAINTY REGARDING MAXIMUM TEMPERATURES ACTUALLY REACHING THE
EXTREME VALUES FORECAST AND THE POSSIBILITY OF LOWER DEW POINTS
AND GUSTY WINDS IN THE AFTERNOON. LATER FORECAST SHIFTS MAY FEEL
THE NEED TO UPGRADE TO A WARNING FOR PORTIONS OF THE ADVISORY AREA
IF THE CURRENT FORECAST HOLDS TRUE. THOSE WITH OUTDOOR ACTIVITIES
PLANNED... AND THOSE WITHOUT ACCESS TO AIR CONDITIONING WILL BE
PARTICULARLY VULNERABLE TO THE HEAT.
WITH THE HEAT AND HUMIDITY IN PLACE... THERE WILL ALSO BE PLENTY
OF INSTABILITY AVAILABLE FOR AFTERNOON THUNDERSTORMS. THIS APPEARS
MOST LIKELY IN NORTHERN AREAS. MODERATE TO STRONG MID/UPPER LEVEL
WINDS SUGGEST THAT ORGANIZED THUNDERSTORMS ARE POSSIBLE... AND
THUS SEVERE THUNDERSTORMS MAY OCCUR. HEAVY RAINFALL WILL ALSO BE A
THREAT DUE TO THE HUMID AIR IN PLACE.
TEMPERATURES WILL NOT COOL DOWN MUCH FRIDAY NIGHT AS HIGH HUMIDITY
AND SOME CLOUD COVER KEEP TEMPERATURES IN THE 70S AT NIGHT FOR
MOST AREAS. THIS WILL MAKE IT DIFFICULT FOR HOT BUILDINGS WITHOUT
AIR CONDITIONING TO COOL DOWN AT NIGHT.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
MAIN FOCUS OF THE EXTENDED FORECAST WILL BE SATURDAY AS SURFACE COLD
FRONT DROPS SOUTH INTO HOT AND VERY HUMID AIR MASS. DECENT HEIGHT
FALLS WILL BE ACCOMPANIED BY MODERATE TO STRONG MID-LEVEL
WINDS...ABOVE HIGHLY UNSTABLE SURFACE AIR. THIS WILL SET THE STAGE
FOR GOOD POTENTIAL FOR SEVERE WEATHER ON SATURDAY...ESPECIALLY IN
THE FORM OF DAMAGING WINDS. ONE LIMITING FACTOR COULD BE TIMING
OF PASSAGE OF PRE-FRONTAL TROUGH AND SUBSEQUENT COLD FRONT...WHICH
MAY CAUSE BEST CONVECTIVE FORCING TO OCCUR TOO EARLY.
HOWEVER...GIVEN WARM AND HUMID FRIDAY NIGHT...COULD SEE SEVERE
WEATHER AS EARLY AS LATE MORNING. THE SCATTERED THUNDERSTORMS WILL
LIKELY CONTINUE INTO EARLY EVENING...BUT SHOULD END QUICKLY
AFTER THAT...WITH COOLER AND AND LESS HUMID BEGINNING TO SPILL
INTO THE CWA BEFORE DAYBREAK SUNDAY.
THE COOLER AND LESS HUMID HIGH PRESSURE WILL REMAIN OVER THE CWA
INTO TUESDAY. THE NEXT CHANCE OF RAIN WILL BE LATE TUESDAY INTO
WEDNESDAY AS A WARM FRONT PUSHES NE INTO NEW ENGLAND.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
SHORT TERM...VFR EXPECTED THROUGH FRIDAY APART FROM
AFTERNOON/EVENING THUNDERSTORMS AND LATE NIGHT FOG AT LEBANON AND
WHITEFIELD.
LONG TERM...STRONG THUNDERSTORMS WITH HEAVY RAIN AND GUSTY WINDS
ARE LIKELY AT TIMES ON SAT INTO SAT EVENING. OTHERWISE EXPECT MAINLY
VFR THROUGH TUE.
&&
.MARINE...
SHORT TERM...SOUTHWEST WINDS WILL INCREASE ON FRIDAY. WAVE HEIGHTS
MAY RISE TO AROUND 5 FT BY FRIDAY NIGHT.
LONG TERM...BORDERLINE SCA ON SATURDAY WITH SEAS TO AROUND 5 FT...
AND SW WINDS APPROACHING 25 KTS. WINDS SHIFT TO NW SATURDAY NIGHT
AND WEAKEN. THE WATERS REMAIN GENERALLY QUIET SUNDAY THRU TUESDAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...HEAT ADVISORY FROM 10 AM TO 7 PM EDT FRIDAY FOR MEZ012-018>021-
023-024.
NH...HEAT ADVISORY FROM 10 AM TO 7 PM EDT FRIDAY FOR NHZ006-008>010-
013-014.
MARINE...NONE.
&&
$$
SYNOPSIS...CEMPA
NEAR TERM...KIMBLE
SHORT TERM...KIMBLE
LONG TERM...CEMPA
AVIATION...CEMPA/KIMBLE
MARINE...CEMPA/KIMBLE
AREA FORECAST DISCUSSION
NWS GRAY ME
1242 PM EDT THU JUL 18 2013
.SYNOPSIS...
A WEAK FRONTAL BOUNDARY WILL STALL OVER SOUTHERN NEW ENGLAND TODAY
AND WILL LIFT NORTH AS A WARM FRONT THURSDAY NIGHT AND EARLY FRIDAY.
A SECOND COLD FRONT WILL APPROACH FROM THE NORTHWEST FRIDAY NIGHT
AND WILL CROSS THE REGION ON SATURDAY. HIGH PRESSURE WILL BUILD IN
BEHIND THE FRONT SATURDAY NIGHT THROUGH SUNDAY. HIGH PRESSURE WILL
SHIFT OFFSHORE ON MONDAY AND WILL REMAIN ANCHORED OFF THE NORTHEAST
COAST THROUGH WEDNESDAY.
&&
.NEAR TERM /TODAY/...
1245PM UPDATE...
SEA BREEZE HAS MOVED ONSHORE AND IS VISIBLE ON RADAR. ANOTHER NORTH
TO SOUTH ORIENTED BOUNDARY OVER FAR SOUTHWEST MAINE IS ALSO VISIBLE
AND ALREADY GENERATING WEAK CONVECTION. EXPECT SCATTERED SHOWERS AND
STORMS TO FORM ON THESE BOUNDARIES THIS AFTERNOON. MEANWHILE...
ADDITIONAL CONVECTION WILL DEVELOP OVER THE ADIRONDACKS IN UPSTATE
NEW YORK AND MOVE EASTWARD WITH THE UPPER LEVEL FLOW. THIS
CONVECTION MAY BE THE MOST LIKELY TO BECOME SEVERE AS SPEED SHEAR
WILL BE SUFFICIENT FOR SUPERCELLS OR MULTICELL CLUSTERS.
930AM UPDATE...
HAVE UPDATED THE FORECAST WITH SLIGHTLY ADJUSTED FORECAST THINKING
FOR TODAY. MORNING SOUNDING SHOWS A FAIR AMOUNT OF DRY AIR ALOFT
THAT WILL MIX DOWN WITH MODERATE HEATING THIS AFTERNOON. ALTHOUGH
TEMPERATURES WILL LIKELY REACH THE 90S IN SOME AREAS... DEW POINTS
WILL FALL INTO THE 60S EVEN IN SOUTHEAST NEW HAMPSHIRE. AS A
RESULT... THIS WILL KEEP HEAT INDEX VALUES BELOW ADVISORY LEVELS
THIS AFTERNOON ALTHOUGH IT WILL BE CLOSE. SHOULD STAY DRY THROUGH
THE MORNING AND INTO THE EARLY AFTERNOON. BUT A SEA BREEZE
BOUNDARY MAY BE THE FOCUS FOR THUNDERSTORM DEVELOPMENT AROUND 2 TO
4 PM. ALSO... TERRAIN MAY BE THE FOCUS FOR THUNDERSTORMS OVER
WESTERN NEW YORK AND SOUTHERN VERMONT WHICH WILL MOVE WEST AND
IMPACT NEW HAMPSHIRE AND WESTERN MAINE LATER IN THE EVENING. THERE
IS SOME CONCERN FOR HEAVY RAIN FROM THESE STORMS TODAY... BUT ALSO
CANNOT RULE OUT THE POSSIBILITY FOR SEVERE WEATHER. THERE IS NO
SEVERE WEATHER OUTLOOK FOR OUR AREA... AND SEVERE WEATHER IS NOT
EXPECTED TO BE WIDESPREAD AS THERE IS NO OBVIOUS SOURCE OF
SYNOPTIC SCALE LIFT. BUT SPEED SHEAR WILL BE STRONG ENOUGH TO
SUPPORT SUPERCELLS ESPECIALLY FURTHER NORTHEAST INTO MAINE FROM
PORTLAND NORTHWARD. THE CONCERN WITH ANY SUPERCELLS THAT FORM HERE
IS THAT THEY WOULD QUICKLY MOVE INTO THE MODIFIED MARINE
ENVIRONMENT BEHIND THE SEA BREEZE BOUNDARY... POSSIBLY LIMITING
THEIR IMPACT. HOWEVER... IF THEY CAN MAINTAIN THEMSELVES... THE
DIRECTIONAL AND SPEED SHEAR WOULD WARRANT CONCERN FOR ROTATING
STORMS. HRRR MODEL SEEMS TO HAVE A GOOD HANDLE ON CONVECTION THIS
AFTERNOON ONCE AGAIN... AND RELIED HEAVILY ON THIS MODEL FOR THE
FORECAST (ALTHOUGH OTHER MODELS ARE IN DECENT AGREEMENT).
PREVIOUS DISCUSSION...
PRE-FRONTAL TROUGH THAT CAUSED ALL THE CONVECTION OVER THE LAST
FEW HOURS IS MOVING EAST AT THE MOMENT. A COLD FRONT IS SAGGING
SOUTH FROM CANADA AND WILL MOVE INTO MAINE TODAY AND MAY MAKE IT
AS FAR SOUTH AS PORTLAND BY LATE IN THE DAY. WITH THE FRONT SLOWLY
MOVING SOUTH EXPECT A CHANCE OF AFTERNOON SHOWERS AND
THUNDERSTORMS TO BREAK OUT IN THE MOUNTAINS. LESSER CHANCES FARTHER
SOUTH. TEMPERATURES WILL WARM INTO THE LOWER 90S IN SOUTHERN AREAS.
&&
.SHORT TERM /TONIGHT AND FRIDAY/...
THE COLD FRONT WILL MOVE BACK NORTH LATE TONIGHT. EXPECT AN
INCREASED CHANCE OF SHOWERS AND THUNDER ALONG AND TO THE NORTH OF
THE FRONT TONIGHT IN CENTRAL AND NORTHEAST PORTIONS OF THE
FORECAST AREA. FOR FRIDAY THE HOT AIR SURGES IN WITH 850
TEMPERATURES AT OR JUST ABOVE 20C. EXPECT HIGH TEMPERATURES IN MID
AND UPPER 90S IN SW MAINE AND SOUTHERN NEW HAMPSHIRE. FRIDAYS
RECORD HIGH FOR CONCORD IS 98 AND THIS COULD BE ATTAINABLE. IN
PORTLAND THE RECORD HIGH IS 94 AND IF THE WINDS REMAIN SW THAT
RECORD COULD FALL TOO. LATER SHIFTS MAY NEED TO ISSUE A HEAT
ADVISORY FOR FRIDAY AS APPARENT TEMPERATURES MAY RISE TO ABOVE 100
DEGREES. EXPECT SCATTERED SHOWERS AND THUNDERSTORMS ESPECIALLY
IN NORTHERN AREAS FRIDAY AFTERNOON. WITH PWATS RUNNING CLOSE TO 2
INCHES EXPECT SOME HEAVY RAIN IN ANY THUNDERSTORMS FRIDAY AND HAVE
MENTIONED THIS IN THE GRIDS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
A VERY WARM AND MUGGY FRIDAY NIGHT ON TAP WITH TEMPERATURES ONLY
SETTLING INTO THE LOWER TO MID 70S AND DEW POINTS NOT MUCH DIFFERENT
IN SOUTHERN ZONES. WILL NOT SEE MUCH DIFFERENCE IN NORTHERN ZONES WHERE
LOWS WILL DIP INTO THE MID 60S TO NEAR 70. WILL SEE A CHANCE OF
SHOWERS OR THUNDERSTORMS THROUGH THE NIGHT WITH HIGHEST POPS IN THE
NORTH AS A COLD FRONT APPROACHES FROM THE NORTHWEST.
SATURDAY STILL LOOKING TO BE A BUSY SEVERE WEATHER DAY AS A STRONG
COLD FRONT SLICES IN FROM THE NORTHWEST DURING THE AFTERNOON AND
EVENING. VERY STRONG FLOW ALOFT WILL LIKELY PRODUCE NUMEROUS REPORTS
OF WIND DAMAGE FROM BOWING LINE SEGMENTS IN THE HIGHLY SHEARED
ENVIRONMENT. WILL BE ANOTHER DAY OF HOT AND MUGGY CONDITIONS WITH
MOST AREAS REACHING THE MID 80S TO LOWER 90S.
COLD FRONT WILL FINALLY PUSH OFFSHORE SATURDAY EVENING TAKING ANY
LINGERING SHOWERS AND THUNDERSTORMS WITH IT. REFRESHING NORTH WINDS
WILL BRING MUCH COOLER AND DRYER AIR BACK TO THE REGION OVERNIGHT AS
HIGH PRESSURE BUILDS IN FROM THE WEST. WILL SEE LOWS BY SUNDAY
MORNING IN THE LOWER 50S NORTH AND UPPER 50S TO LOWER 60S SOUTH.
HIGH PRESSURE WILL CONTINUE TO BUILD IN FROM THE WEST SUNDAY AND
MONDAY SETTING THE STAGE FOR SOME VERY AGREEABLE SUMMER WEATHER.
EXPECT HIGHS BOTH DAYS IN THE 70S TO NEAR 80.
HIGH PRESSURE WILL SHIFT OFFSHORE BY LATE IN THE DAY MONDAY AND WILL
REMAIN NEARLY STATIONARY OFF THE EAST COAST TUESDAY AND WEDNESDAY.
WILL SEE A GRADUAL MODERATION IN TEMPERATURE AND HUMIDITY AS RETURN
FLOW BRINGS WARMER AIR BACK INTO THE REGION. LOW PRESSURE TRACKING
NORTH THROUGH THE EASTERN GREAT LAKES WILL DRIVE A COLD FRONT TOWARD
THE REGION WEDNESDAY NIGHT AND THURSDAY BRINGING WITH IT A CHANCE OF
SHOWERS FOR LATER IN THE WEEK.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
SHORT TERM...SOME MVFR/IFR POSSIBLE EARLY THIS MORNING IN SOME FOG
OTHERWISE VFR EXCEPT IN ANY SHOWERS AND THUNDERSTORMS.
LONG TERM...VFR FRIDAY NIGHT WITH AREAS IFR/LIFR CEILINGS/VSBY IN
MORNING VALLEY FOG. VFR SATURDAY WITH AREAS OF MVFR/IFR CEILINGS
AND VSBY IN WIDESPREAD SHOWERS AND THUNDERSTORMS. VFR SATURDAY
NIGHT THROUGH MONDAY.
&&
.MARINE...
SHORT TERM...WIND AND SEAS WILL REMAIN BELOW SCA CRITERIA.
LONG TERM...SCA LIKELY FOR FRIDAY NIGHT INTO SATURDAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
NEAR TERM UPDATE... KIMBLE
AREA FORECAST DISCUSSION
NWS GRAY ME
940 AM EDT THU JUL 18 2013
.SYNOPSIS...
A WEAK FRONTAL BOUNDARY WILL STALL OVER SOUTHERN NEW ENGLAND TODAY
AND WILL LIFT NORTH AS A WARM FRONT THURSDAY NIGHT AND EARLY FRIDAY.
A SECOND COLD FRONT WILL APPROACH FROM THE NORTHWEST FRIDAY NIGHT
AND WILL CROSS THE REGION ON SATURDAY. HIGH PRESSURE WILL BUILD IN
BEHIND THE FRONT SATURDAY NIGHT THROUGH SUNDAY. HIGH PRESSURE WILL
SHIFT OFFSHORE ON MONDAY AND WILL REMAIN ANCHORED OFF THE NORTHEAST
COAST THROUGH WEDNESDAY.
&&
.NEAR TERM /TODAY/...
930AM UPDATE...
HAVE UPDATED THE FORECAST WITH SLIGHTLY ADJUSTED FORECAST THINKING
FOR TODAY. MORNING SOUNDING SHOWS A FAIR AMOUNT OF DRY AIR ALOFT
THAT WILL MIX DOWN WITH MODERATE HEATING THIS AFTERNOON. ALTHOUGH
TEMPERATURES WILL LIKELY REACH THE 90S IN SOME AREAS... DEW POINTS
WILL FALL INTO THE 60S EVEN IN SOUTHEAST NEW HAMPSHIRE. AS A
RESULT... THIS WILL KEEP HEAT INDEX VALUES BELOW ADVISORY LEVELS
THIS AFTERNOON ALTHOUGH IT WILL BE CLOSE. SHOULD STAY DRY THROUGH
THE MORNING AND INTO THE EARLY AFTERNOON. BUT A SEA BREEZE
BOUNDARY MAY BE THE FOCUS FOR THUNDERSTORM DEVELOPMENT AROUND 2 TO
4 PM. ALSO... TERRAIN MAY BE THE FOCUS FOR THUNDERSTORMS OVER
WESTERN NEW YORK AND SOUTHERN VERMONT WHICH WILL MOVE WEST AND
IMPACT NEW HAMPSHIRE AND WESTERN MAINE LATER IN THE EVENING. THERE
IS SOME CONCERN FOR HEAVY RAIN FROM THESE STORMS TODAY... BUT ALSO
CANNOT RULE OUT THE POSSIBILITY FOR SEVERE WEATHER. THERE IS NO
SEVERE WEATHER OUTLOOK FOR OUR AREA... AND SEVERE WEATHER IS NOT
EXPECTED TO BE WIDESPREAD AS THERE IS NO OBVIOUS SOURCE OF
SYNOPTIC SCALE LIFT. BUT SPEED SHEAR WILL BE STRONG ENOUGH TO
SUPPORT SUPERCELLS ESPECIALLY FURTHER NORTHEAST INTO MAINE FROM
PORTLAND NORTHWARD. THE CONCERN WITH ANY SUPERCELLS THAT FORM HERE
IS THAT THEY WOULD QUICKLY MOVE INTO THE MODIFIED MARINE
ENVIRONMENT BEHIND THE SEA BREEZE BOUNDARY... POSSIBLY LIMITING
THEIR IMPACT. HOWEVER... IF THEY CAN MAINTAIN THEMSELVES... THE
DIRECTIONAL AND SPEED SHEAR WOULD WARRANT CONCERN FOR ROTATING
STORMS. HRRR MODEL SEEMS TO HAVE A GOOD HANDLE ON CONVECTION THIS
AFTERNOON ONCE AGAIN... AND RELIED HEAVILY ON THIS MODEL FOR THE
FORECAST (ALTHOUGH OTHER MODELS ARE IN DECENT AGREEMENT).
PREVIOUS DISCUSSION...
PRE-FRONTAL TROUGH THAT CAUSED ALL THE CONVECTION OVER THE LAST
FEW HOURS IS MOVING EAST AT THE MOMENT. A COLD FRONT IS SAGGING
SOUTH FROM CANADA AND WILL MOVE INTO MAINE TODAY AND MAY MAKE IT
AS FAR SOUTH AS PORTLAND BY LATE IN THE DAY. WITH THE FRONT SLOWLY
MOVING SOUTH EXPECT A CHANCE OF AFTERNOON SHOWERS AND
THUNDERSTORMS TO BREAK OUT IN THE MOUNTAINS. LESSER CHANCES FARTHER
SOUTH. TEMPERATURES WILL WARM INTO THE LOWER 90S IN SOUTHERN AREAS.
&&
.SHORT TERM /TONIGHT AND FRIDAY/...
THE COLD FRONT WILL MOVE BACK NORTH LATE TONIGHT. EXPECT AN
INCREASED CHANCE OF SHOWERS AND THUNDER ALONG AND TO THE NORTH OF
THE FRONT TONIGHT IN CENTRAL AND NORTHEAST PORTIONS OF THE
FORECAST AREA. FOR FRIDAY THE HOT AIR SURGES IN WITH 850
TEMPERATURES AT OR JUST ABOVE 20C. EXPECT HIGH TEMPERATURES IN MID
AND UPPER 90S IN SW MAINE AND SOUTHERN NEW HAMPSHIRE. FRIDAYS
RECORD HIGH FOR CONCORD IS 98 AND THIS COULD BE ATTAINABLE. IN
PORTLAND THE RECORD HIGH IS 94 AND IF THE WINDS REMAIN SW THAT
RECORD COULD FALL TOO. LATER SHIFTS MAY NEED TO ISSUE A HEAT
ADVISORY FOR FRIDAY AS APPARENT TEMPERATURES MAY RISE TO ABOVE 100
DEGREES. EXPECT SCATTERED SHOWERS AND THUNDERSTORMS ESPECIALLY
IN NORTHERN AREAS FRIDAY AFTERNOON. WITH PWATS RUNNING CLOSE TO 2
INCHES EXPECT SOME HEAVY RAIN IN ANY THUNDERSTORMS FRIDAY AND HAVE
MENTIONED THIS IN THE GRIDS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
A VERY WARM AND MUGGY FRIDAY NIGHT ON TAP WITH TEMPERATURES ONLY
SETTLING INTO THE LOWER TO MID 70S AND DEW POINTS NOT MUCH DIFFERENT
IN SOUTHERN ZONES. WILL NOT SEE MUCH DIFFERENCE IN NORTHERN ZONES WHERE
LOWS WILL DIP INTO THE MID 60S TO NEAR 70. WILL SEE A CHANCE OF
SHOWERS OR THUNDERSTORMS THROUGH THE NIGHT WITH HIGHEST POPS IN THE
NORTH AS A COLD FRONT APPROACHES FROM THE NORTHWEST.
SATURDAY STILL LOOKING TO BE A BUSY SEVERE WEATHER DAY AS A STRONG
COLD FRONT SLICES IN FROM THE NORTHWEST DURING THE AFTERNOON AND
EVENING. VERY STRONG FLOW ALOFT WILL LIKELY PRODUCE NUMEROUS REPORTS
OF WIND DAMAGE FROM BOWING LINE SEGMENTS IN THE HIGHLY SHEARED
ENVIRONMENT. WILL BE ANOTHER DAY OF HOT AND MUGGY CONDITIONS WITH
MOST AREAS REACHING THE MID 80S TO LOWER 90S.
COLD FRONT WILL FINALLY PUSH OFFSHORE SATURDAY EVENING TAKING ANY
LINGERING SHOWERS AND THUNDERSTORMS WITH IT. REFRESHING NORTH WINDS
WILL BRING MUCH COOLER AND DRYER AIR BACK TO THE REGION OVERNIGHT AS
HIGH PRESSURE BUILDS IN FROM THE WEST. WILL SEE LOWS BY SUNDAY
MORNING IN THE LOWER 50S NORTH AND UPPER 50S TO LOWER 60S SOUTH.
HIGH PRESSURE WILL CONTINUE TO BUILD IN FROM THE WEST SUNDAY AND
MONDAY SETTING THE STAGE FOR SOME VERY AGREEABLE SUMMER WEATHER.
EXPECT HIGHS BOTH DAYS IN THE 70S TO NEAR 80.
HIGH PRESSURE WILL SHIFT OFFSHORE BY LATE IN THE DAY MONDAY AND WILL
REMAIN NEARLY STATIONARY OFF THE EAST COAST TUESDAY AND WEDNESDAY.
WILL SEE A GRADUAL MODERATION IN TEMPERATURE AND HUMIDITY AS RETURN
FLOW BRINGS WARMER AIR BACK INTO THE REGION. LOW PRESSURE TRACKING
NORTH THROUGH THE EASTERN GREAT LAKES WILL DRIVE A COLD FRONT TOWARD
THE REGION WEDNESDAY NIGHT AND THURSDAY BRINGING WITH IT A CHANCE OF
SHOWERS FOR LATER IN THE WEEK.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
SHORT TERM...SOME MVFR/IFR POSSIBLE EARLY THIS MORNING IN SOME FOG
OTHERWISE VFR EXCEPT IN ANY SHOWERS AND THUNDERSTORMS.
LONG TERM...VFR FRIDAY NIGHT WITH AREAS IFR/LIFR CEILINGS/VSBY IN
MORNING VALLEY FOG. VFR SATURDAY WITH AREAS OF MVFR/IFR CEILINGS
AND VSBY IN WIDESPREAD SHOWERS AND THUNDERSTORMS. VFR SATURDAY
NIGHT THROUGH MONDAY.
&&
.MARINE...
SHORT TERM...WIND AND SEAS WILL REMAIN BELOW SCA CRITERIA.
LONG TERM...SCA LIKELY FOR FRIDAY NIGHT INTO SATURDAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
NEAR TERM UPDATE... KIMBLE
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
726 PM EDT FRI JUL 19 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 356 PM EDT FRI JUL 19 2013
A COLD FRONT WILL PRESS THROUGH SOUTHWEST LOWER MICHIGAN TONIGHT
WHICH WILL BE PRECEDED BY SHOWERS AND THUNDERSTORMS. SOME OF THE
STORMS THIS EVENING MAY BE SEVERE WITH DAMAGING WINDS AND TORRENTIAL
RAINS. THE SHOWERS AND STORMS WILL MOVE SOUTH INTO INDIANA AND OHIO
SATURDAY MORNING. A REFRESHING COOLER AND DRIER AIR MASS WILL SETTLE
INTO THE STATE FOR THE WEEKEND. HIGHS WILL BE CLOSER TO NORMALS FOR
THIS TIME OF YEAR WITH LOWER 80S ON SATURDAY AND AROUND 80 ON SUNDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 356 PM EDT FRI JUL 19 2013
STILL A COMPLEX CONVECTIVE EVOLUTION IN PLACE...WITH A PRE FRONTAL
CONVERGENCE ZONE RESULTING IN SCATTERED THUNDERSTORM DEVELOPMENT AT
THIS TIME FROM NEAR HOLLAND EAST TO IONIA. THESE STORMS WILL
CONTINUE TO DEVELOP AS MIXED LAYER CAPE VALUES ARE ON THE ORDER OF
2000 J/KG AT THIS TIME. TWO MAIN CORRIDORS OF INSTABILITY ARE IN
PLACE ONE POOLED NEAR THE FRONT OFF TO THE NORTH WHICH STRETCHES
FROM NORTHERN LAKE MICHIGAN INTO CENTRAL WISCONSIN. THE OTHER AREA
OF EVEN HIGHER INSTABILITY IS NOSED INTO SOUTH CENTRAL LOWER
MICHIGAN FROM GRR SOUTH AND EAST. THIS ZONE IS IN PLAY DUE TO THE
FACT THAT THE SOUTHWEST FLOW IS NOT OFF THE LAKE HERE.
DYNAMICS REMAIN A FACTOR AS THE MID LEVEL SHORTWAVE TROUGH EDGES IN
ALONG WITH AN ENTRANCE REGION TO A 250MB JET STREAK. REALLY ALL
INGREDIENTS ARE IN PLACE...MOISTURE...INSTABILITY AND LIFT. ENVISION
THE CURRENT LINE CONTINUING TO DEVELOP WITH SOME SEVERE WIND GUSTS
EMBEDDED. THE FRONT TO THE NORTH WILL BE THE WILD CARD BUT EXPECT TO
SEE A LINEAR LINE OF STORMS FORM ALONG IT AND PROGRESS SOUTH. THESE
STORMS MAY BE MOVING INTO CENTRAL LOWER MICHIGAN IN THE 7-9PM TIME
RANGE. SEVERE WEATHER WITH THESE IS POSSIBLE BUT THERE IS A SOLID
LAKE SHADOW OF WEAKER INSTABILITY THERE.
MAIN THREAT CONTINUES TO BE DAMAGING WINDS AS STRONG SYNOPTIC SCALE
FLOW IS IN PLACE IN THE 850-500MB LAYER.
COOLER AND DRIER AIR WILL BRING QUIET WEATHER SATURDAY INTO SUNDAY.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 356 PM EDT FRI JUL 19 2013
COOLER PATTERN TO PERSIST WITH NEAR NORMAL TO SLIGHTLY BELOW NORMAL
TEMPERATURES LOOKING MORE LIKELY THROUGH NEXT WEEK. THIS MEANS HIGHS
IN THE UPPER 70S TO LOWER 80S WITH LOWS IN THE LOWER 60S. THERE WILL
BE SCATTERED CHANCES FOR SHOWERS AND THUNDERSTORMS ESPECIALLY DURING
THE FIRST HALF OF NEXT WEEK...BUT OVERALL NO ORGANIZED SIGNIFICANT
WEATHER EXPECTED MONDAY THROUGH FRIDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 726 PM EDT FRI JUL 19 2013
THE BIG QUESTION IS DOES A LINE OF STORMS FORM JUST AHEAD OF THE
FRONT OR NOT? CURRENTLY SCATTERED STORMS ARE TRYING TO ORGANIZE
NEAR MBL...WHICH IS JUST AHEAD OF THE COLD FRONT. THE TIMING TOOL
TAKES THAT TO MKG BY 0430Z AND TO THE I-94 TAF SITES BY 11Z. THIS
SEEMS TO SLOW... THE LATEST HRRR REDEVELOPS STORMS OVER SOUTHERN
LAKE MICHIGAN BY 01Z AND HEADS THOSE STORMS OUT OF THE CWA BY 04Z.
SINCE THERE IS A JET SPEED MAX THAT COMES THROUGH THE AREA IN THE
03Z TIME FRAME... IT WOULD SEEM THERE IS A GOOD CHANCE THE STORMS
COULD YET BETTER ORGANIZE. SO NOT HAVING ANYTHING SOLID TO TRACK
INTO THE TAF SITES...I KEPT THE VCTS GOING 09Z AT MOST OF THE TAF
SITES. BEHIND THE FRONT SKIES WILL CLEAR SO MOST OF SATURDAY
SHOULD BE CLEAR WITH A NORTHWEST WIND AROUND 10 KNOTS.
&&
.MARINE...
ISSUED AT 356 PM EDT FRI JUL 19 2013
A COMPLEX MARINE SCENARIO IS IN PLACE WITH AN ONGOING HIGH WAVE
EVENT IN PROGRESS. WAVES OF 4 TO 7 FEET ARE COMMON PLACE IN THE
NEARSHORE AREA AT THIS TIME. THE WIND WILL DIMINISH TONIGHT AND THE
WAVES WILL DAMPEN OUT AS WELL...SUBSIDING BELOW SMALL CRAFT ADVISORY
CRITERIA AFTER MIDNIGHT. A HIGH SWIM HAZARD RISK WILL CONTINUE
THROUGH SUNSET.
THE COMPLICATING FACTOR IS IT APPEARS ANOTHER HIGH WAVE EVENT WILL
FOLLOW QUICKLY ON THE HEELS OF THIS ONE TOMORROW AFTERNOON IN THE
NORTHERLY FLOW BEHIND THE COLD FRONT. WILL HOLD OFF ON ISSUING A
BEACH HAZARDS STATEMENT AND SMALL CRAFT ADVISORY FOR SATURDAY INTO
SATURDAY NIGHT...LETTING THIS ONE END FIRST. A CLOSER LOOK WILL BE
TAKEN AT TOMORROWS EVENT BY THE MID SHIFT.
&&
.HYDROLOGY...
ISSUED AT 356 PM EDT FRI JUL 19 2013
LOCAL FLOODING POTENTIAL WILL CONTINUE UNTIL THE FRONT AND THEREFORE
STORM THREAT IS SOUTH OF THE AREA. BY SATURDAY MORNING THE FRONT
SHOULD BE SOUTH OF SOUTHWEST LOWER MICHIGAN. ANY STORMS THIS EVENING
AND TONIGHT GIVEN A VERY MOIST AIRMASS IN PLACE WILL BE CAPABLE OF
TORRENTIAL DOWNPOURS. LOCALIZED FLOODING IS VERY POSSIBLE IN AN AIR
MASS SUCH AS THIS. WIDESPREAD HEAVY AREAL RAINFALL IS NOT EXPECTED
HOWEVER. SO...A FLASH FLOOD TYPE THREAT WILL EXIST THIS EVENING AND
TONIGHT BUT WIDESPREAD RIVER ISSUES ARE NOT ANTICIPATED GIVEN THE
LOCAL NATURE OF THE HEAVY RAINS. A COOLER AND DRIER AIR MASS WILL
PUSH INTO THE AREA FOR SATURDAY AND SUNDAY.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT UNTIL 11 PM EDT THIS EVENING FOR MIZ037-
043-050-056-064-071.
HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR MIZ037>040-043>046-
050>052-056>059-064>067-071>074.
LM...SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR LMZ844>849.
&&
$$
SYNOPSIS...DUKE
SHORT TERM...DUKE
LONG TERM...MACZKO
AVIATION...WDM
HYDROLOGY...DUKE
MARINE...DUKE
AREA FORECAST DISCUSSION
NWS GAYLORD MI
358 PM EDT THU JUL 18 2013
.SYNOPSIS...
ISSUED AT 358 PM EDT THU JUL 18 2013
ONE MORE DAY OF HOT AND HUMID CONDITIONS ARE EXPECTED ACROSS
NORTHERN MICHIGAN FRIDAY BEFORE A COUPLE OF COLD FRONTS PASSING
THROUGH THE GREAT LAKES WILL COOL THINGS DOWN DRAMATICALLY BY
SATURDAY. PASSAGE OF THESE FRONTS WILL BE ACCOMPANIED BY
THUNDERSTORM ACTIVITY...SOME OF WHICH COULD BE SEVERE OVERNIGHT
AND INTO FRIDAY. THE SEVERE WEATHER THREAT WILL END BY FRIDAY
EVENING...WITH A DRY AND PLEASANT WEEKEND ON TAP.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 358 PM EDT THU JUL 18 2013
HIGH IMPACT WEATHER POTENTIAL: ISOLATED SEVERE THUNDERSTORMS
POSSIBLE THROUGH EARLY EVENING. INCREASING THREAT FOR DAMAGING
WINDS TONIGHT OVER EASTERN UPPER AND THE TIP OF THE MITT...MOVING
SOUTH INTO NORTHERN LOWER MICHIGAN ON FRIDAY.
HOT AND HUMID WEATHER CONTINUES...WITH HEAT ADVISORIES BEING
CONFINED CLOSER TO SAGINAW BAY FOR THE DAY ON FRIDAY AHEAD OF
ARRIVING COLD FRONT.
OVERVIEW: FLAT RIDGING CONTINUES ACROSS THE GREAT LAKES REGION THIS
AFTERNOON WITH STRONGER SHORTWAVE ENERGY NOW BECOMING EVIDENT
DROPPING OUT OF NORTHERN MANITOBA...WITH AN ADDITIONAL WAVE OVER
SOUTHERN SASKATCHEWAN. AT THE SURFACE...LOW PRESSURE HAS TAKEN
SHAPE OVER EASTERN NORTH DAKOTA THIS HOUR WITH QUASI-STATIONARY
WARM FRONT EXTENDING EAST ACROSS NORTHERN MINNESOTA AND UPPER
MICHIGAN. STORMS HAVE PERCOLATED ALONG THIS BOUNDARY ALL DAY GIVEN
SOUPY WARM SECTOR AIRMASS AND SOUTHWESTERLY WINDS RIDING OVER THE
BOUNDARY IN THE PRESENCE OF AMPLE UNCAPPED INSTABILITY AND GRADUALLY
INCREASING DEEP LAYER SHEAR. ON THE MESOSCALE...AND OUTFLOW
BOUNDARY WORKED SOUTH INTO NORTHERN LOWER HELPING TO TRIGGER
CONVECTION SOUTH OF THE FRONT...WITH SOME OF THIS ACTIVITY ONGOING
AS I TYPE. TEMPS IN AREAS NOT SEEING RAINFALL ARE NOT DISAPPOINTING
THE HOT/HUMID TALK OF LATE...WITH TVC 96 AND CAD 97 THIS HOUR.
THROUGH EARLY EVENING: ISOLATED TO SCATTERED TSRA ACTIVITY WILL
CONTINUE OVER NORTHERN LOWER...ALTHOUGH DECREASING IN COVERAGE AS WE
AWAIT FURTHER DEVELOPMENT UPSTREAM.
TONIGHT: BROAD AREA OF HEIGHT FALLS OVERSPREADS THE GREAT LAKES
REGION AHEAD OF STRONG SHORTWAVE WHOSE CORE WILL BE DROPPING THROUGH
NORTHERN MANITOBA. BENEATH THIS FEATURE THE SURFACE LOW WILL TRACK
NORTH AND EAST...TO NEAR THE SOUTHERN SHORE OF JAMES BAY BY DAYBREAK
FRIDAY. HEIGHT FALLS AND TIME OF DAY WILL COAX A STRENGTHENING LLJ
AT H8 FROM NORTHERN WISCONSIN NORTH AND EAST ACROSS LAKE SUPERIOR.
SYNOPTIC SETUP AND SHEAR PARAMETERS CERTAINLY FAVOR PROGRESSIVE MCS
DEVELOPMENT WITH OVER 30KTS OF 0-3KM BULK SHEAR...BUT NO MORE THAN
10KTS ABOVE THIS TO 6KM. THE QUESTION BECOMES...WHERE IS THIS
CONVECTION LIKELY TO FORM/MOVE?
THE SYNOPTICALLY-FAVORED LOCATION WOULD BE NEAR OR JUST NORTH OF LAKE
SUPERIOR GIVEN THE CURRENT FRONTAL BOUNDARY AND EXPECTED LLJ
LOCATION. THIS IS WELL SHOWN BY THE NEW 12Z NAM AND PROBABLY THE
STRONGEST GUIDANCE CONSENSUS WHICH BRINGS TO DISTINCT CONVECTIVE
COMPLEXES OVER OR NORTH OF MY NORTHERN ZONES. AFTERNOON RADAR
TRENDS...HOWEVER...SUGGEST DEVELOPMENT A LITTLE FURTHER SOUTH AND
WEST...OVER THE ARROWHEAD OF MINNESOTA ALONG OUTFLOW BOUNDARY IN
THIS AREA. EARLY AFTERNOON HRRR IS ONTO THIS TREND...AND WITH
FORWARD-PROPAGATING CORFIDI VECTORS SUGGESTING AN ESE STORM
MOTION...LOOKS TO BRING ACTIVITY TOWARDS EASTERN UPPER LATER THIS
EVENING...WITH PERHAPS MORE ACTIVITY DEVELOPING UPSTREAM THROUGH THE
FIRST HALF OF TONIGHT AS THE LLJ STRENGTHENS IMMEDIATELY AHEAD OF
THE SURFACE COLD FRONT. THUS...WILL INCREASE POPS OVER EASTERN
UPPER TO LIKELY DURING THE EVENING HOURS...BUT KEEP LIKELIES
PRIMARILY RESTRICTED TO EASTERN UPPER OVERNIGHT GIVEN EXPECTED STORM
PROPAGATION. SOME ROGUE STORM DEVELOPMENT TO THE SOUTH IS
POSSIBLE...BUT LOWER POPS WARRANTED HERE. SEVERE THREAT IS
THERE...MORE ISOLATED WIND/HAIL IN THE NEAR TERM...WITH A MORE
ORGANIZED WIND THREAT TAKING SHAPE THIS EVENING.
REALLY LIKE INHERITED VERY WARM OVERNIGHT LOWS GIVEN INCREASING
CLOUD COVER AND COUPLED BOUNDARY LAYER FLOW NOT GIVING TEMPERATURES
MUCH ROOM TO FALL. SO...LOOKING LIKE THE LAST UNCOMFORTABLE SLEEPING
NIGHT MAY BE THE WORST /AT LEAST OVER NORTHERN LOWER/ WHERE MID TO
UPPER 70S SHOULD ABOUT DO IT.
FRIDAY: SOMEWHAT UNUSUAL FOR THE APX CWA SO FAR THIS WARM
SEASON...WE HAVE A COLD FRONT PROGGED TO PUSH THROUGH THE FORECAST
AREA IN THE MIDDLE OF PEAK HEATING. CLEARLY...OVERNIGHT CONVECTIVE
ACTIVITY WILL HAVE A HUGE IMPACT ON WHAT HAPPENS THUNDERSTORM-WISE
DURING THE DAY. COULD VERY WELL BE SOME ONGOING ACTIVITY ACROSS THE
CWA EARLY...WITH THE BEST CHANCES AGAIN BEING OVER EASTERN
UPPER...CLOSEST TO THE ARRIVING COLD FRONT. THIS AT LEAST SPELLS
THE POTENTIAL FOR SOME DESTABILIZATION AHEAD OF AFOREMENTIONED COLD
FRONT /ESP OVER NORTHERN LOWER/ WHICH LOOKS TO PUSH THROUGH THE CWA
IN THE 18-00Z TIME FRAME. SHEAR PARAMETERS ARE IMPRESSIVE AS THE
PRIMARY BELT OF THE WESTERLIES SINKS INTO OUR AREA. 0-3KM BULK
SHEAR REACHES 40KTS...WITH 50KTS+ OF 0-6KM SHEAR. SHEAR LOOKS TO
ONLY HAVE A SLIGHT ANGLE TO THE ARRIVING BOUNDARY...SO A LINEAR MODE
WITH EMBEDDED BOWING SEGMENTS COULD CERTAINLY BE SUPPORTED. THIS IS
WELL CAPTURED BY THE DAY 2 SLIGHT RISK AREA FROM SPC.
AS FOR TEMPERATURES AND HEAT ADVISORY CONCERNS...THE EARLIER
EXPANSION OF THE HEAT ADVISORY TO THE SOUTHEASTERN ZONES FOR THE DAY
LOOKS RIGHT ON...GIVEN STRENGTHENING SOUTHWEST WINDS GIVING SOME
DOWNSLOPING ASSISTANCE TO THESE AREAS...WHICH SHOULD PUSH TEMPS INTO
THE LOW/MID 90S BEFORE CONVECTIVE ACTIVITY ARRIVES FROM THE NORTH
AND WEST. ELSEWHERE...LOW TO MID 80S LOOK GOOD GIVEN EXPECTED CLOUD
COVER AND RAINFALL.
&&
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 358 PM EDT THU JUL 18 2013
RECENT TRENDS...TEMPERATURES: HOT...OBVIOUSLY. 1-3C ABOVE NORMAL
LAST 7 DAYS AND PRETTY MUCH FOR THE MONTH OF JULY THUS FAR.
PRECIPITATION/HYDROLOGY: BAND OF HEAVIER PRECIPITATION ACROSS
EASTERN UPPER/STRAITS REGION LAST NIGHT (RADAR ESTIMATES 3+ INCHES
FAR WESTERN MACKINAC/SCHOOLCRAFT COUNTIES) MOST SUBSTANTIAL RAINFALL
OF LAST SEVEN DAYS...OUTSIDE OF SCATTERED DIURNAL ACTIVITY MUCH OF
NORTHERN LOWER MICHIGAN HASN`T SEEN A DROP. 30 DAY STANDARDIZED
PRECIP INDEX CONTINUING TO TREND DRIER...ESPECIALLY ACROSS PORTIONS
OF UPPER MICHIGAN THAT SAW GOOD RAINS OVERNIGHT. STREAMFLOWS ON
AREA RIVERS STILL MOSTLY NEAR NORMAL...HYDROGRAPHS FLAT GIVEN LACK
OF RENEWED RUNOFF. TOPSOIL MOISTURE STILL IN GOOD SHAPE DESPITE
RECENT DRYNESS.
LARGE SCALE PATTERN/FORECAST...CONTINENTAL U.S. DOMINATED BY FLAT
RIDGING...WITH THE SOUTHERN EDGE OF THE MAIN WESTERLIES RUNNING
STRAIGHT WEST-EAST ALONG THE CANADIAN BORDER. PATTERN MORE BLOCKY
UPSTREAM ACROSS THE PACIFIC WITH "OFF THE CHART" -EPO/-WPO INDICES.
BALL OF ENERGY EMERGING FROM ABOVE THE ARCTIC CIRCLE AND ENTERING
FAR NORTHERN SASKATCHEWAN/MANITOBA THIS AFTERNOON WILL BE THE
CATALYST TO THE END OF THE CURRENT HEAT AND HUMIDITY THAT HAS BEEN
LINGERING OVER THE UPPER LAKES THIS WEEK. STRONG HEIGHT FALLS WILL
DROP ACROSS THE REGION FRIDAY AND DRIVE COOLER AIR INTO MICHIGAN FOR
THE WEEKEND. QUASI-ZONAL FLOW THEN FORECAST TO SET UP ACROSS THE
NORTHERN HALF OF THE CONUS FOR THE FIRST PART OF NEXT WEEK...WITH
SOME LOW AMPLITUDE TROUGHING FROM THE GREAT LAKES/OHIO VALLEY
NORTHEAST INTO NEW ENGLAND.
AHEAD OF THE CANADIAN HEIGHT FALLS WILL BE A PAIR OF COLD FRONTS
THAT WILL SWEEP ACROSS NORTHERN MICHIGAN FRIDAY/FRIDAY NIGHT. THIS
WILL PUSH A REFRESHINGLY COOLER/DRIER AIR MASS INTO THE UPPER LAKES
SATURDAY...WHILE HIGH PRESSURE SETTLES INTO THE REGION FOR SUNDAY.
HIGH PRESSURE RETREATS TO THE EAST MONDAY WITH RETURN FLOW OF WARMER
AIR BACK INTO THE UPPER MIDWEST/UPPER LAKES GETTING UNDERWAY. MAIN
FORECAST CONCERN THROUGH THE WEEKEND WILL BE WITH THE TRANSITION
FROM WARM/MUGGY TO COOLER WEATHER FRIDAY NIGHT.
FRIDAY NIGHT THROUGH SUNDAY: WEATHER...LEAD COLD FRONT WILL LIKELY
STILL BE IN THE VICINITY OF THE M-72/US-10 CORRIDOR FRIDAY
EVENING...WITH CONVECTION (POTENTIALLY SEVERE) LIKELY ONGOING AHEAD
OF THIS BOUNDARY WHICH SHOULD SINK INTO SOUTHERN LOWER MICHIGAN BY
MIDNIGHT. SECONDARY BOUNDARY COMES IN HOT ON ITS HEELS...PUSHED
ALONG BY THE MAIN SHORT WAVE TROUGH THAT WILL BE DIGGING SOUTHEAST.
MUCH OF THE FORCING ALOFT LOOKS TO REMAIN NORTH OF THE FORECAST
AREA...SOME QG SUBSIDENCE CROSSES NORTHERN MICHIGAN BEHIND THE LEAD
FRONT. SO WILL RUN WITH THUNDERSTORM CHANCES BASICALLY SOUTH OF A
MBL-APN LINE FRIDAY EVENING...AND DRY THINGS OUT THEREAFTER HEADING
INTO SATURDAY. WEAK SHORT WAVE TROUGH WILL TRACK THROUGH THE
MIDWEST SUNDAY...WHICH COULD PUSH CLOUDS INTO NORTHWEST LOWER DURING
THE AFTERNOON HOURS.
WINDS...SHIFTING TO THE NORTHWEST BEHIND SECONDARY COLD FRONT EARLY
SATURDAY MORNING...WINDS WILL BE A BIT GUSTY SATURDAY GIVEN GOOD
POST-FRONTAL MIXING (LOW LEVEL COLD ADVECTION/DIURNAL HEATING) ON
THE ORDER OF 20+MPH. WINDS FORECAST TO SETTLE DOWN SATURDAY NIGHT
AS HIGH BUILDS IN AND GRADIENT DROPS OFF. SUNDAY WINDS WILL BE
LIGHT AND DOMINATED BY LAKE BREEZE EVOLUTION.
TEMPERATURES...OVERNIGHT LOWS SHOULD FINALLY BREAK INTO THE 50S
ACROSS EASTERN UPPER AND MUCH OF NORTHWEST/NORTH CENTRAL LOWER
SATURDAY MORNING. SHOULD SEE A NICE DROP IN HUMIDITY EXPECTED
SATURDAY WITH DEW POINTS FALLING INTO THE 40S DURING THE AFTERNOON.
SATURDAY AFTERNOON HIGHS 65-70 EASTERN UPPER...UPPER 60S-LOWER 70S
MUCH OF NORTHWEST LOWER WITH MID-UPPER 70S NORTHEAST LOWER.
SEASONABLY COOL LOWS FOR SUNDAY MORNING WITH TEMPERATURES DROPPING
INTO THE 40S AWAY FROM THE IMMEDIATE LAKESHORES. SUNDAY HIGHS
AROUND 70-MID 70S EXPECTED.
EXTENDED FORECAST (MONDAY THROUGH THURSDAY): MIDWEST SHORT WAVE
CURRENTLY LOOKS AS IF IT WILL PASS SOUTH OF LOWER MICHIGAN AND INTO
THE OHIO VALLEY SUNDAY NIGHT/MONDAY. IF THAT IS THE CASE THEN WILL
PROBABLY START THE NEW WORK WEEK WITH A DRY FORECAST. BETTER THREAT
FOR RAIN MAY ARRIVE WITH A COLD FRONT HEADING INTO THE MIDWEEK
PERIOD...THEN WILL START THE NEW THURSDAY FORECAST OUT DRY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 143 PM EDT THU JUL 18 2013
SUMMARY: SCATTERED SHOWER AND THUNDERSTORM ACTIVITY WILL CONTINUE
INTO TONIGHT AS A STATIONARY FRONT BISECTS THE REGION. A POTENT
COLD FRONT WILL ARRIVE ON FRIDAY BRINGING A ROUND OF WIDESPREAD
SHOWERS AND THUNDERSTORMS. IMPROVING CONDITIONS WILL ARRIVE AT THE
VERY END...OR JUST AFTER THE END OF THE UPCOMING TAF PERIOD.
SHOWER AND THUNDERSTORM ACTIVITY LOOK MOST LIKELY TO IMPACT PLN
HEADING INTO THE EVENING HOURS...WITH ACTIVITY CURRENTLY OVER NE
LOWER EXPECTED TO REMAIN SOUTHEAST OF MBL-TVC-APN. A SEVERE STORM
CANNOT BE RULED OUT. OVERNIGHT...EXPECT NUMEROUS SHOWERS AND
THUNDERSTORMS ACROSS EASTERN UPPER...THAT MAY SINK SOUTH TOWARDS
PLN. OTHERWISE...FAR BETTER CHANCES FOR MORE WIDESPREAD
SHOWERS/STORMS COME FRIDAY MORNING WITH THE COLD FRONT. WILL
MENTION A FEW HOUR PERIOD OF TSRA AT THE MOST LIKELY TIME FOR
THESE TO MOVE THROUGH...WITH IMPROVEMENT TOWARDS THE VERY END OF
THE TAF PERIOD AT PLN.
LLWS: SOUTHWESTERLY LOW LEVEL JET WILL STRENGTHEN THIS EVENING
WITH 35KT WINDS EXPECTED AT 2KFT.
WINDS GENERALLY BECOMING WEST SOUTHWEST AROUND 10KTS THIS EVENING
AND OVERNIGHT BEFORE STRENGTHENING TO 14G20KTS FROM THE SOUTHWEST
AHEAD OF THE FRONT ON FRIDAY. EXPECT A WIND SHIFT TO WEST
NORTHWEST BY FRIDAY AFTERNOON.
&&
.MARINE...
ISSUED AT 358 PM EDT THU JUL 18 2013
SUMMARY: A LOW PRESSURE SYSTEM WILL PASS NORTH OF THE GREAT LAKES
TONIGHT AND ON FRIDAY...WITH STRENGTHENING SOUTHWESTERLY WINDS
EXPECTED AHEAD OF AN APPROACHING COLD FRONT. NORTHWEST WINDS WILL
DEVELOP IN THE WAKE OF THIS SYSTEM ON SATURDAY WITH VERY QUIET
CONDITIONS TO END THE WEEKEND AS HIGH PRESSURE SETTLES OVERHEAD.
WILL ISSUE SMALL CRAFTS FOR LATE TONIGHT AND FRIDAY ACROSS MOST OF
NORTHERN LAKE MICHIGAN GIVEN THE STRENGTHENING SOUTHWESTERLY FLOW
THIS EVENING. THESE WILL LIKELY NEED TO BE EXPANDED EAST INTO PARTS
OF LAKE HURON ON FRIDAY. MARGINAL SCA/S MAY AGAIN BE NECESSARY ON
SATURDAY GIVEN STRENGTHENING NORTHWEST FLOW.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...HEAT ADVISORY UNTIL 8 AM EDT FRIDAY FOR MIZ016>034.
HEAT ADVISORY UNTIL 8 PM EDT FRIDAY FOR MIZ035-036-041-042.
LH...NONE.
LM...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 5 PM EDT FRIDAY
FOR LMZ323-342-344>346.
LS...NONE.
&&
$$
SYNOPSIS...JPB
SHORT TERM...ARNOTT
LONG TERM...JPB
AVIATION...ARNOTT
MARINE...ARNOTT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
209 PM EDT THU JUL 18 2013
.UPDATE...
ISSUED AT 1054 AM EDT THU JUL 18 2013
12Z SFC ANALYSIS SHOWS SFC LOW OVER CENTRAL ND WITH WARM FRONT
ARCING FROM FARGO TO JUST SOUTH OF DLH AND NEAR HYR. STATIONARY
FRONT PRETTY MUCH BISECTS UPR MICHIGAN FROM NORTH TO SOUTH. MORE
OF A ONSHORE/MARINE INFLUENCE IS NOTED AT CMX/P59 AND TO MARQUETTE
VCNTY. CLUSTER OF SHOWERS/TSRA WITH HEAVY DOWNPOURS WORKING ACROSS
CNTRL UPR MICHIGAN AS OF 1430Z. NOT MUCH OCCURRING INTO SOUTHWEST
UPR MICHIGAN AND NORTHERN WI/CENTRAL MN. 12Z SOUNDINGS FM MPX AND
GRB SHOWED STEEP LAPSE RATES BUT CAPPING WAS NOT THAT STRONG.
CONVECTIVE TEMPS WERE AROUND 90 DEGREES. MAY SEE ISOLD-SCT SHRA/TSRA
FORM DURING PEAK HEATING BUT THERE MAY BE A BIT OF A LULL BTWN EARLY
AFTN AND LATE AFTN. BASED ON H85 TEMPS PUSHING 20C THIS AFTN AND
SHARP CLEARING OCCURRING BEHIND THIS INITIAL SHRA/TSRA...RAISED
TEMPS BACK TO AROUND 90 DEGREES FOR MUCH OF CWA...EVEN MID 90S
POSSIBLE OVER INTERIOR SCNTRL.
GIVEN DEGREE OF INSTABILITY /SBCAPES OVER 2000 J/KG DCAPES NEAR
1000J/KG/ AND INCREASING SHEAR /0-6KM SHEAR OVER 40 KTS PUSHING IN
FROM NORTHERN MN AHEAD OF STRONG SHORTWAVE MOVING ACROSS SOUTHERN
MANITOBA/ PER SPC MESOANALYSIS PAGE...IF STORMS DEVELOP THIS AFTN
DURING PEAK HEATING THEY WOULD LIKELY BECOME SEVERE. A SITUATION
WITH A CONDITIONAL PROBABILITY THOUGH AS THERE IS NOT MUCH OF A
TRIGGER IN THE LOW-LEVELS. SINCE THE STATIONARY FRONT IS OVERHEAD
AND BASED ON RAP FORECAST SOUNDINGS SHOWING SHARPLY CURVED HODOGRAPHS
AND SINCE 0-1KM SHEAR IS 25-30 KTS...STILL CANNOT RULE OUT ISOLD
TORNADO OCCURRING. LCL HEIGHTS ARE ON THE HIGHER SIDE THOUGH AND
MIGHT MITIGATE THAT RISK.
STILL APPEARS THAT ANOTHER ROUND OR TWO OF SHRA/TSRA ROLL ACROSS UPR
MICHIGAN THIS EVENING INTO TONIGHT ALONG THE SFC FRONT AND JUST AHEAD
OF STRONG COLD FRONT. POTENTIAL STILL THERE FOR STRONG WINDS AND HEAVY
RAIN. NO CHANGES MADE TO TONIGHT AT THIS POINT THOUGH.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 434 AM EDT THU JUL 18 2013
OTHER THAN SHORT TERM UPDATES...DID NOT CHANGE MUCH FROM THE
PREVIOUS FORECAST FOR TONIGHT/TONIGHT. SINCE THE CONVECTION THAT MAY
MOVE ACROSS THE CWA TODAY HAS NOT DEVELOPED...AND SINCE GUIDANCE HAS
NOT CHANGED MUCH IN THE LAST DAY OR SO...THERE WAS NO REASON TO
CHANGE THE FORECAST TOO MUCH. HEAVY RAIN CONTINUES TO BE THE MOST
OBVIOUS THREAT FROM CONVECTION TODAY...BUT LARGE HAIL AND DAMAGING
WINDS ARE ALSO POSSIBLE...AND A SMALL THREAT OF A TORNADO CAN NOT BE
RULED OUT COMPLETELY.
THE SYNOPTIC PATTERN FOR THE PERIOD HAS THE CWA BETWEEN A LOW OVER
HUDSON BAY AND A BROAD HIGH S OF THE GREAT LAKES. THE HIGH WILL
BREAK DOWN AND MOVE S WHILE PART OF THE LOW WILL BREAK OFF AND MOVE
INTO NRN SASK BY 12Z FRI.
STORMS HAVE BEEN FOCUSING ALONG A WEAK STATIONARY
BOUNDARY...COMBINED WITH THE NOCTURNAL LOW LEVEL JET...ACROSS THE
CWA SO FAR TODAY. A FEW OF THESE STORMS HAVE BEEN STRONGER...WITH
PLENTY OF MID LEVEL ROTATION...BUT NO LOW LEVEL ROTATION AND THEY
HAVE BEEN PRETTY PULSE LIKE. THINK THE BOUNDARY WILL STAY NEARLY
STATIONARY TODAY...PUTTING MUCH OF THE CWA IN THE WARM SECTOR AS
SWLY LOW LEVEL FLOW INCREASES AHEAD OF A SFC TROUGH/COLD FRONT THAT
WILL MOVE IN LATE TODAY/TONIGHT. MID/UPPER LEVEL FLOW WILL BE
PARALLEL TO THE FRONT...SO TRAINING PRECIP IS A GOOD BET.
ALSO...PWATS WILL BE 1.75-2.00 INCHES /180-200 PERCENT OF
NORMAL/...SO MOISTURE WILL BE PREVALENT. EXACT LOCATION OF HEAVIER
PRECIP WILL DEPEND ON TRACK OF THUNDERSTORMS AND WHERE THE BOUNDARY
/THAT WILL BE CONVECTIVELY ENHANCED/ WILL BE...SO IT IS IMPOSSIBLE
TO PREDICT WITH ANY GREAT ACCURACY BEFORE THE STORMS HAVE FORMED.
DID ADD HEAVY RAINFALL ATTRIBUTE TO WEATHER GRIDS FOR TODAY/TONIGHT.
WITH HIGH TEMPS OF AROUND 80F TO 90F TODAY...AND PLENTY OF
MOISTURE...INSTABILITY WILL BE PRETTY GOOD. MLCAPES OF 1500J/KG TO
JUST OVER 2000J/KG ARE FORECAST BY MODELS...WITH 0-6KM BULK SHEAR OF
30-40KTS. MOST OF THAT SHEAR WILL BE UNIDIRECTIONAL...BUT SOME
VEERING WITH HEIGHT IS MODELED IN THE LOW LEVELS. MAIN STORM MODE
SHOULD BE SINGLE CELL OR MULTICELL CLUSTERS WITH SOME CHANCE OF SOME
SUPERCELL ACTIVITY. THE CAPE/SHEAR COMBINED WITH DRY VERY LOW LEVELS
/MIXING LAYER/ WILL MAKE FOR A WIND DAMAGE THREAT THIS AFTERNOON AS
DCAPE VALUES APPROACH 1000J/KG. LARGE HAIL WILL ALSO BE A THREAT.
TORNADO THREAT IS MINIMAL...BUT CAN NOT BE COMPLETELY RULED OUT WITH
MORE SIGNIFICANT STORM/BOUNDARY INTERACTIONS.
FOR TONIGHT...MAIN CONCERN...SEVERE WEATHER WISE...IS FOR HIGH WINDS
ASSOCIATED WITH A POSSIBLE MCS MOVING THROUGH OR NEAR THE CWA.
MODELS HAVE BEEN PERSISTENT WITH BRINGING A CONVECTIVE CLUSTER
ACROSS THE CWA...FOLLOWING THE MEAN FLOW...CAPE GRADIENT AND THE
FRONT. EVEN THOUGH A NEAR SFC INVERSION SHOULD FORM...AN EML WILL
STAY OVER THE CWA...SO LOW LEVELS WILL REMAIN DRY...WHICH SHOULD
HELP COLD POOL PROCESSES AND INCREASE THE WIND THREAT. ALSO...THAT
SFC TROUGH/COLD FRONT WILL MOVE INTO THE CWA WITH UPPER LEVEL HEIGHT
FALLS AS THE UPPER LEVEL TROUGH APPROACHES THE CWA. WITH THE UPPER
TROUGH MOVING SOUTH...THE CWA WILL COME UNDER THE RIGHT ENTRANCE
REGION OF AN UPPER LEVEL JET...ALSO PROMOTING PRECIP. HEAVY RAIN
POTENTIAL DEFINITELY CONTINUES INTO TONIGHT...JUST A MATTER OF
EXACTLY WHERE THAT MAY HAPPEN.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 434 AM EDT THU JUL 18 2013
FRI...AS UPR TROF CENTERED OVER HUDSON BAY DEEPENS INTO ONTARIO...
COLD FNT MOVING INTO WRN UPR MI ARND SUNRISE ON FRI WL MOVE TO THE
SE OF THE CWA IN THE AFTN. WITH THE ARRIVAL OF DRIER AIR/VIGOROUS
NEGATIVE H85 THETA E ADVECTION...LINGERING SHRA/TS WL END NW TO
SE...BUT GOING LIKELY POPS OVER THE SE CWA IN THE MRNG SEEM
APPROPRIATE. STEEPENING MID LVL LAPSE RATES MAY MAINTAIN POPS OVER
MAINLY THE SCENTRAL FOR A LONGER TIME...BUT THE SHARP DRYING ALF WL
ACT TO LIMIT THIS POTENTIAL. THE RETURN OF MORE AFTN SUNSHINE...H85
TEMPS AS HI AS 17C AT 00Z SAT...AND DOWNSLOPING WNW FLOW WL HELP
BOOST MAX TEMPS OVER THE SCENTRL WELL INTO THE 80S TO NEAR 90. THE
NW FLOW OFF LK SUP WL BRING COOLER WX TO THE W.
FRI NGT INTO SAT...MODELS INDICATE A REINFORCING SHRTWV/SECONDARY
COLD FNT WL SWEEP THRU THE UPR LKS. IN FACT...THE 00Z NAM SHOWS MORE
SGNFT DPVA/QVECTOR CNVGC AND GENERATES SOME PCPN LATE FRI NGT/EARLY
SAT. THE 00Z GFS/12Z ECMWF SHOW MORE DEEP LYR QVECTOR DVGC/A WEAKER
SFC REFLECTION/FNT WITH DRY AIR DOMINATING. SINCE THE DISTURBANCE/
FNT WL BE ARRIVING AT MIN DIURNAL HEATING TIME WITH AN ABSENCE OF
ANY MOISTENING AT H85...OPTED TO MAINTAIN GOING DRY FCST AND JUST
ADD MORE CLDS TO THE FCST. THESE CLDS WL
LATER SAT INTO SUN...UNDER CONFLUENT NW FLOW ALF...CNDN HI PRES IS
FCST TO BUILD OVER LK SUP SAT EVNG AND DRIFT ONLY SLOWLY SE TO OVER
LK HURON LATE SUN. WITH THE ARRIVAL OF MUCH DRIER AIR /PWAT FCST TO
REACH CLOSE TO 0.50 INCH BY 12Z SUN/...EXPECT MOCLR CONDITIONS. A
STEADY N WIND OFF LK SUP WL LIMIT THE DIURNAL TEMP RECOVERY ON
SAT... ESPECIALLY NEAR THE SHORE. OVERNGT LOWS ON SAT NGT WL FALL
SHARPLY INTO THE 40S OVER THE COOLER INTERIOR LOCATIONS EARLY SUN
MRNG WITH LIGHT WINDS. WITH H85 TEMPS PROGGED NEAR 10C LATER
SUN...EXPECT DAYTIME MAX TEMPS TO RISE INTO THE 70S AWAY THE
MODERATING INFLUENCE OF THE GREAT LKS AS RELATIVELY WEAK PRES
GRADIENT ALLOWS LK BREEZES TO FORM OFF ALL THE LKS.
EXTENDED...AS IS OFTEN THE CASE IN SUMMER...MODELS HAVE SHOWN
CONSIDERABLE INCONSISTENCIES IN THE HANDLING OF SHRTWVS EMBEDDED IN
WNW FLOW ALF EARLY NEXT WEEK. SOME OF THE MOST PROGRESSIVE GUIDANCE
INDICATES SOME PCPN MAY REACH THE WRN CWA AS EARLY AS LATE SUN.
CONSIDERING THE CONSIDERABLE INCONSISTENCY IN A RELATIVELY
UNPREDICTABLE PATTERN...OPTED TO MAINTAIN THE MODEL CONSENSUS FCST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 159 PM EDT THU JUL 18 2013
SCT TSRA DEVELOPING SCNTRL MAY IMPACT SAW THROUGH MID AFTN. ADDITIONAL
TSRA MAY AFFECT IWD THOUGH THEY MAY END UP JUST EAST OF THAT SITE.
VFR CONDITIONS EXPECTED...BUT HEAVY DOWNPOURS AND STRONG WIND GUSTS
MAY OCCUR. ADDITIONAL TSRA POSSIBLE TONIGHT AS COMPLEX OF SHRA/TSRA
FORMING OVER NORTHERN MN ROLL ESE THROUGH THE EVENING AND OVERNIGHT
HOURS. MAIN HAZARD WITH THESE STORMS WILL BE GUSTY WINDS AND HEAVY
RAIN. EXPECT PRECIP TO END AROUND DAYBREAK ON FRIDAY. MAIN ISSUE FOR
MOST OF FRIDAY WILL BE GUSTY WNW WINDS...ESPECIALLY AT MORE EXPOSED
CMX LOCATION WHERE WIND GUSTS COULD REACH OVER 20 KTS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 434 AM EDT THU JUL 18 2013
WITH RELATIVELY WEAK PRES GRADIENT AND HI STABILITY OVER THE
RELATIVELY COOL LAKE WATERS...EXPECT WINDS NO HIGHER THAN 20 KTS
THIS FORECAST PERIOD. THE MAIN WEATHER CONCERN WILL BE FOG WITH A
HUMID AIRMASS DOMINATING. THIS FOG IS LIKELY TO BE MOST WIDESPREAD
TONIGHT FOLLOWING SOME STRONG TO POSSIBLY SEVERE THUNDERSTORMS
THAT WILL FURTHER SATURATE THE MARINE LAYER. THE ARRIVAL OF DRIER
AIR BEHIND A COLD FRONTAL PASSAGE ON FRI SHOULD DISSIPATE THE FOG.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...JLA
SHORT TERM...TITUS
LONG TERM...KC
AVIATION...JLA
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1104 AM EDT THU JUL 18 2013
.UPDATE...
ISSUED AT 1054 AM EDT THU JUL 18 2013
12Z SFC ANALYSIS SHOWS SFC LOW OVER CENTRAL ND WITH WARM FRONT
ARCING FROM FARGO TO JUST SOUTH OF DLH AND NEAR HYR. STATIONARY
FRONT PRETTY MUCH BISECTS UPR MICHIGAN FROM NORTH TO SOUTH. MORE
OF A ONSHORE/MARINE INFLUENCE IS NOTED AT CMX/P59 AND TO MARQUETTE
VCNTY. CLUSTER OF SHOWERS/TSRA WITH HEAVY DOWNPOURS WORKING ACROSS
CNTRL UPR MICHIGAN AS OF 1430Z. NOT MUCH OCCURRING INTO SOUTHWEST
UPR MICHIGAN AND NORTHERN WI/CENTRAL MN. 12Z SOUNDINGS FM MPX AND
GRB SHOWED STEEP LAPSE RATES BUT CAPPING WAS NOT THAT STRONG.
CONVECTIVE TEMPS WERE AROUND 90 DEGREES. MAY SEE ISOLD-SCT SHRA/TSRA
FORM DURING PEAK HEATING BUT THERE MAY BE A BIT OF A LULL BTWN EARLY
AFTN AND LATE AFTN. BASED ON H85 TEMPS PUSHING 20C THIS AFTN AND
SHARP CLEARING OCCURRING BEHIND THIS INITIAL SHRA/TSRA...RAISED
TEMPS BACK TO AROUND 90 DEGREES FOR MUCH OF CWA...EVEN MID 90S
POSSIBLE OVER INTERIOR SCNTRL.
GIVEN DEGREE OF INSTABILITY /SBCAPES OVER 2000 J/KG DCAPES NEAR
1000J/KG/ AND INCREASING SHEAR /0-6KM SHEAR OVER 40 KTS PUSHING IN
FROM NORTHERN MN AHEAD OF STRONG SHORTWAVE MOVING ACROSS SOUTHERN
MANITOBA/ PER SPC MESOANALYSIS PAGE...IF STORMS DEVELOP THIS AFTN
DURING PEAK HEATING THEY WOULD LIKELY BECOME SEVERE. A SITUATION
WITH A CONDITIONAL PROBABILITY THOUGH AS THERE IS NOT MUCH OF A
TRIGGER IN THE LOW-LEVELS. SINCE THE STATIONARY FRONT IS OVERHEAD
AND BASED ON RAP FORECAST SOUNDINGS SHOWING SHARPLY CURVED HODOGRAPHS
AND SINCE 0-1KM SHEAR IS 25-30 KTS...STILL CANNOT RULE OUT ISOLD
TORNADO OCCURRING. LCL HEIGHTS ARE ON THE HIGHER SIDE THOUGH AND
MIGHT MITIGATE THAT RISK.
STILL APPEARS THAT ANOTHER ROUND OR TWO OF SHRA/TSRA ROLL ACROSS UPR
MICHIGAN THIS EVENING INTO TONIGHT ALONG THE SFC FRONT AND JUST AHEAD
OF STRONG COLD FRONT. POTENTIAL STILL THERE FOR STRONG WINDS AND HEAVY
RAIN. NO CHANGES MADE TO TONIGHT AT THIS POINT THOUGH. &&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 434 AM EDT THU JUL 18 2013
OTHER THAN SHORT TERM UPDATES...DID NOT CHANGE MUCH FROM THE
PREVIOUS FORECAST FOR TONIGHT/TONIGHT. SINCE THE CONVECTION THAT MAY
MOVE ACROSS THE CWA TODAY HAS NOT DEVELOPED...AND SINCE GUIDANCE HAS
NOT CHANGED MUCH IN THE LAST DAY OR SO...THERE WAS NO REASON TO
CHANGE THE FORECAST TOO MUCH. HEAVY RAIN CONTINUES TO BE THE MOST
OBVIOUS THREAT FROM CONVECTION TODAY...BUT LARGE HAIL AND DAMAGING
WINDS ARE ALSO POSSIBLE...AND A SMALL THREAT OF A TORNADO CAN NOT BE
RULED OUT COMPLETELY.
THE SYNOPTIC PATTERN FOR THE PERIOD HAS THE CWA BETWEEN A LOW OVER
HUDSON BAY AND A BROAD HIGH S OF THE GREAT LAKES. THE HIGH WILL
BREAK DOWN AND MOVE S WHILE PART OF THE LOW WILL BREAK OFF AND MOVE
INTO NRN SASK BY 12Z FRI.
STORMS HAVE BEEN FOCUSING ALONG A WEAK STATIONARY
BOUNDARY...COMBINED WITH THE NOCTURNAL LOW LEVEL JET...ACROSS THE
CWA SO FAR TODAY. A FEW OF THESE STORMS HAVE BEEN STRONGER...WITH
PLENTY OF MID LEVEL ROTATION...BUT NO LOW LEVEL ROTATION AND THEY
HAVE BEEN PRETTY PULSE LIKE. THINK THE BOUNDARY WILL STAY NEARLY
STATIONARY TODAY...PUTTING MUCH OF THE CWA IN THE WARM SECTOR AS
SWLY LOW LEVEL FLOW INCREASES AHEAD OF A SFC TROUGH/COLD FRONT THAT
WILL MOVE IN LATE TODAY/TONIGHT. MID/UPPER LEVEL FLOW WILL BE
PARALLEL TO THE FRONT...SO TRAINING PRECIP IS A GOOD BET.
ALSO...PWATS WILL BE 1.75-2.00 INCHES /180-200 PERCENT OF
NORMAL/...SO MOISTURE WILL BE PREVALENT. EXACT LOCATION OF HEAVIER
PRECIP WILL DEPEND ON TRACK OF THUNDERSTORMS AND WHERE THE BOUNDARY
/THAT WILL BE CONVECTIVELY ENHANCED/ WILL BE...SO IT IS IMPOSSIBLE
TO PREDICT WITH ANY GREAT ACCURACY BEFORE THE STORMS HAVE FORMED.
DID ADD HEAVY RAINFALL ATTRIBUTE TO WEATHER GRIDS FOR TODAY/TONIGHT.
WITH HIGH TEMPS OF AROUND 80F TO 90F TODAY...AND PLENTY OF
MOISTURE...INSTABILITY WILL BE PRETTY GOOD. MLCAPES OF 1500J/KG TO
JUST OVER 2000J/KG ARE FORECAST BY MODELS...WITH 0-6KM BULK SHEAR OF
30-40KTS. MOST OF THAT SHEAR WILL BE UNIDIRECTIONAL...BUT SOME
VEERING WITH HEIGHT IS MODELED IN THE LOW LEVELS. MAIN STORM MODE
SHOULD BE SINGLE CELL OR MULTICELL CLUSTERS WITH SOME CHANCE OF SOME
SUPERCELL ACTIVITY. THE CAPE/SHEAR COMBINED WITH DRY VERY LOW LEVELS
/MIXING LAYER/ WILL MAKE FOR A WIND DAMAGE THREAT THIS AFTERNOON AS
DCAPE VALUES APPROACH 1000J/KG. LARGE HAIL WILL ALSO BE A THREAT.
TORNADO THREAT IS MINIMAL...BUT CAN NOT BE COMPLETELY RULED OUT WITH
MORE SIGNIFICANT STORM/BOUNDARY INTERACTIONS.
FOR TONIGHT...MAIN CONCERN...SEVERE WEATHER WISE...IS FOR HIGH WINDS
ASSOCIATED WITH A POSSIBLE MCS MOVING THROUGH OR NEAR THE CWA.
MODELS HAVE BEEN PERSISTENT WITH BRINGING A CONVECTIVE CLUSTER
ACROSS THE CWA...FOLLOWING THE MEAN FLOW...CAPE GRADIENT AND THE
FRONT. EVEN THOUGH A NEAR SFC INVERSION SHOULD FORM...AN EML WILL
STAY OVER THE CWA...SO LOW LEVELS WILL REMAIN DRY...WHICH SHOULD
HELP COLD POOL PROCESSES AND INCREASE THE WIND THREAT. ALSO...THAT
SFC TROUGH/COLD FRONT WILL MOVE INTO THE CWA WITH UPPER LEVEL HEIGHT
FALLS AS THE UPPER LEVEL TROUGH APPROACHES THE CWA. WITH THE UPPER
TROUGH MOVING SOUTH...THE CWA WILL COME UNDER THE RIGHT ENTRANCE
REGION OF AN UPPER LEVEL JET...ALSO PROMOTING PRECIP. HEAVY RAIN
POTENTIAL DEFINITELY CONTINUES INTO TONIGHT...JUST A MATTER OF
EXACTLY WHERE THAT MAY HAPPEN.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 434 AM EDT THU JUL 18 2013
FRI...AS UPR TROF CENTERED OVER HUDSON BAY DEEPENS INTO ONTARIO...
COLD FNT MOVING INTO WRN UPR MI ARND SUNRISE ON FRI WL MOVE TO THE
SE OF THE CWA IN THE AFTN. WITH THE ARRIVAL OF DRIER AIR/VIGOROUS
NEGATIVE H85 THETA E ADVECTION...LINGERING SHRA/TS WL END NW TO
SE...BUT GOING LIKELY POPS OVER THE SE CWA IN THE MRNG SEEM
APPROPRIATE. STEEPENING MID LVL LAPSE RATES MAY MAINTAIN POPS OVER
MAINLY THE SCENTRAL FOR A LONGER TIME...BUT THE SHARP DRYING ALF WL
ACT TO LIMIT THIS POTENTIAL. THE RETURN OF MORE AFTN SUNSHINE...H85
TEMPS AS HI AS 17C AT 00Z SAT...AND DOWNSLOPING WNW FLOW WL HELP
BOOST MAX TEMPS OVER THE SCENTRL WELL INTO THE 80S TO NEAR 90. THE
NW FLOW OFF LK SUP WL BRING COOLER WX TO THE W.
FRI NGT INTO SAT...MODELS INDICATE A REINFORCING SHRTWV/SECONDARY
COLD FNT WL SWEEP THRU THE UPR LKS. IN FACT...THE 00Z NAM SHOWS MORE
SGNFT DPVA/QVECTOR CNVGC AND GENERATES SOME PCPN LATE FRI NGT/EARLY
SAT. THE 00Z GFS/12Z ECMWF SHOW MORE DEEP LYR QVECTOR DVGC/A WEAKER
SFC REFLECTION/FNT WITH DRY AIR DOMINATING. SINCE THE DISTURBANCE/
FNT WL BE ARRIVING AT MIN DIURNAL HEATING TIME WITH AN ABSENCE OF
ANY MOISTENING AT H85...OPTED TO MAINTAIN GOING DRY FCST AND JUST
ADD MORE CLDS TO THE FCST. THESE CLDS WL
LATER SAT INTO SUN...UNDER CONFLUENT NW FLOW ALF...CNDN HI PRES IS
FCST TO BUILD OVER LK SUP SAT EVNG AND DRIFT ONLY SLOWLY SE TO OVER
LK HURON LATE SUN. WITH THE ARRIVAL OF MUCH DRIER AIR /PWAT FCST TO
REACH CLOSE TO 0.50 INCH BY 12Z SUN/...EXPECT MOCLR CONDITIONS. A
STEADY N WIND OFF LK SUP WL LIMIT THE DIURNAL TEMP RECOVERY ON
SAT... ESPECIALLY NEAR THE SHORE. OVERNGT LOWS ON SAT NGT WL FALL
SHARPLY INTO THE 40S OVER THE COOLER INTERIOR LOCATIONS EARLY SUN
MRNG WITH LIGHT WINDS. WITH H85 TEMPS PROGGED NEAR 10C LATER
SUN...EXPECT DAYTIME MAX TEMPS TO RISE INTO THE 70S AWAY THE
MODERATING INFLUENCE OF THE GREAT LKS AS RELATIVELY WEAK PRES
GRADIENT ALLOWS LK BREEZES TO FORM OFF ALL THE LKS.
EXTENDED...AS IS OFTEN THE CASE IN SUMMER...MODELS HAVE SHOWN
CONSIDERABLE INCONSISTENCIES IN THE HANDLING OF SHRTWVS EMBEDDED IN
WNW FLOW ALF EARLY NEXT WEEK. SOME OF THE MOST PROGRESSIVE GUIDANCE
INDICATES SOME PCPN MAY REACH THE WRN CWA AS EARLY AS LATE SUN.
CONSIDERING THE CONSIDERABLE INCONSISTENCY IN A RELATIVELY
UNPREDICTABLE PATTERN...OPTED TO MAINTAIN THE MODEL CONSENSUS FCST.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 742 AM EDT THU JUL 18 2013
THE MAIN FOCUS OF CONCERN FOR THIS FORECAST PERIOD WILL BE
THUNDERSTORM DEVELOPMENT ALONG/NEAR THE COLD FRONT ACROSS UPPER
MICHIGAN. EXPECT A DECREASE IN SHOWER AND THUNDERSTORM COVERAGE LATE
THIS MORNING INTO THIS AFTERNOON. TOUGH TO PIN POINT ANY EXACT
TIMING FOR THE STORMS...BUT THE EXPECTATION IS THAT ANY STORM WILL
CREATE TORRENTIAL DOWNPOURS AND BRIEF IFR CONDITIONS. THE NEXT ROUND
OF PRECIP DEVELOPS LATE THIS AFTN INTO TONIGHT. THESE COULD END UP
BEING STRONG TO SEVERE ESPECIALLY IF THEY DEVELOP INTO A ORGANIZED
CONVECTIVE COMPLEX.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 434 AM EDT THU JUL 18 2013
WITH RELATIVELY WEAK PRES GRADIENT AND HI STABILITY OVER THE
RELATIVELY COOL LAKE WATERS...EXPECT WINDS NO HIGHER THAN 20 KTS
THIS FORECAST PERIOD. THE MAIN WEATHER CONCERN WILL BE FOG WITH A
HUMID AIRMASS DOMINATING. THIS FOG IS LIKELY TO BE MOST WIDESPREAD
TONIGHT FOLLOWING SOME STRONG TO POSSIBLY SEVERE THUNDERSTORMS
THAT WILL FURTHER SATURATE THE MARINE LAYER. THE ARRIVAL OF DRIER
AIR BEHIND A COLD FRONTAL PASSAGE ON FRI SHOULD DISSIPATE THE FOG.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...JLA
SHORT TERM...TITUS
LONG TERM...KC
AVIATION...TITUS
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
148 AM EDT THU JUL 18 2013
.UPDATE...
ISSUED AT 1038 PM EDT WED JUL 17 2013
THE FRONTAL BOUNDARY IS BASICALLY RIGHT OVER THE AREA. SCATTERED
SHOWERS AND THUNDERSTORMS DEVELOPED THIS AFTERNOON HELPED BY THE
UNSTABLE AIRMASS AND LAKE BREEZE BOUNDARIES. NOW...SHOWERS AND
THUNDERSTORMS HAVE ONCE AGAIN DEVELOPED AND FOCUSED MORE ON THE MAIN
FRONTAL BOUNDARY. THIS ACTIVITY EXTENDS FROM UPPER MICHIGAN WEST
INTO NRN MN. THE MAIN CONCERN IN THE UPDATE IS THE EVOLUTION OF
CONVECTION OVERNIGHT. SOME OF THE RAPID UPDATE MODELS INCLUDING THE
LOCAL RUNS OF THE WRF BASED ON THE RAP...SUGGEST THAT AS THE 850MB
FLOW BACKS TONIGHT AND STRENGTHENS OVER MN...AN MCS TYPE FEATURE
WILL DEVELOP AND TRACK ALONG THE 850MB THERMAL GRADIENT.
MEANWHILE...THE NAM AND THE HRRR SUGGEST THAT MULTICELL ACTIVITY
WILL CONTINUE ALONG THE FRONT AND TRACK OVER UPPER MICHIGAN
TONIGHT...ESPECIALLY LATE AS THE LOW LEVEL JET NOSES INTO THE AREA.
LOOKING AT THE LATEST RADAR TRENDS AND LACK OF ANY SIGNIFICANT
CONVECTIVE CLOUD DEVELOPMENT SOUTH OF THE FRONT...TEND TO BELIEVE
THE SCENARIO OF MORE MULTICELL DEVELOPMENT WITH SCATTERED-NUMEROUS
SHOWERS AND STORMS CONTINUING ALL NIGHT ESPECIALLY ACROSS THE WEST
HALF NEAR THE FRONTAL BOUNDARY. MOST LIKELY THE MAIN CONCERN TONIGHT
WILL BE THE HEAVY RAINFALL GIVEN THE HIGH FREEZING LEVELS ABOVE
15KFT AND PRECIPITABLE WATER VALUES ABOVE 2 INCHES...ALTHOUGH IF
SOME ORGANIZATION OF CONVECTION CAN OCCUR...UNIDIRECTIONAL EFFECTIVE
SHEAR VALUES OF 30-40KT WOULD SUGGEST A POTENTIAL WIND THREAT IF A
COLD POOL COULD DEVELOP.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 432 PM EDT WED JUL 17 2013
SFC OBS SHOW THAT AFTERNOON INLAND TEMPS HAVE REACHED THE CONVECTIVE
TEMPERATURE AT MANY LOCATIONS (INTO THE UPPER 80S AND LOWER 90S) AND
THUS HAVE STARTED TO SEE ISOLD SHRA/TSRA BEGINNING TO FORM OVER FAR
WRN UPR MI AND ALONG THE LAKE SUPERIOR LAKE BREEZE AND VNCTY OF
STALLED OUT FRONT IN NORTH CENTRAL UPR MI. WITH SBCAPE VALUES OF
2000-2500 J/KG AND ALONG WITH EFFECTIVE BULK SHEAR VALUES 35-40 KT
THERE IS A CHANCE THAT SOME OF THESE STORMS COULD BECOME SVR THIS
AFTERNOON INTO THIS EVENING. AS A RESULT SPC HAS MUCH OF UPR MI IN A
SLIGHT RISK FOR DAY1 CONVECTIVE OUTLOOK AND HAS JUST ISSUED A SWOMCD
FOR POSSIBLE SVR TSTM WATCH ISSUANCE. UNIDIRECTIONAL FLOW PARALLEL
TO THE SURFACE BOUNDARIES COULD SUPPORT STORM DEVELOPMENT FAVORING
FORWARD PROPAGATING LINE SEGMENTS AND SMALL BOW ECHOES WITH THE
POTENTIAL FOR DAMAGING WINDS AND HAIL ALONG WITH HEAVY RAIN.
EXPECT MUCH OF THE CONVECTION FORMING NOW TO GRADUALLY DIMINISH BY
LATE THIS EVENING AS HEATING/INSTABILITY WANES A BIT. STORMS SHOULD
THEN REDEVELOP LATER TONIGHT TO THE WEST OVER NRN MN AS WARM
ADVECTION KICKS IN ALONG STALLED OUT FRONTAL BOUNDARY IN RESPONSE TO
SHORTWAVE ROUNDING BROAD 5H RIDGE. LOOK FOR STORMS TO THEN TRACK ESE
ALONG FRONTAL BOUNDARY AND 850-300 MB THCKNS LINES AND INTO UPPER MI
ON THURSDAY...ESPECIALLY AFFECTING THE NRN AND ERN PORTIONS OF THE
CWA. WITH PWATS EXCEEDING 2.00 INCHES OR 190-195 PCT OF NORMAL...
TORRENTIAL HEAVY RAIN WILL BE POSSIBLE WITH STORMS AND THERE IS A
POTENTIAL FOR SOME FLASH FLOODING IF STORMS CONTINUE TO TRACK OVER
THE NRN AND ERN PORTIONS OF THE CWA DURING THE DAY ON THURSDAY. WITH
MLCAPES VALUES FORECAST TO BE NEAR 1500 J/KG AND DEEP LAYER SHEAR
VALUES OF 35-45 KT THERE IS AGAIN A POTENTIAL FOR SVR STORMS ON THU
AND SPC HAS ALL OF UPR MI HIGHLIGHTED IN SLIGHT RISK. COMBINATION OF
VEERING WIND PROFILE IN THE LOWER LVLS...STRONG
INSTABILITY...MODERATE TO STRONG DEEP LAYER...AND VERY MOIST
DEWPOINTS IN THE LOWER 70S CONTRIBUTING TO LOW LFC HEIGHTS COULD ALL
SUPPORT SUPERCELL DEVELOPMENT. ALTHOUGH THE PRIMARY THREATS WITH
THURSDAYS STORMS WILL LIKELY BE DAMAGING WIND...HEAVY RAIN AND LARGE
HAIL...ISOLD TORNADOES WILL ALSO BE POSSIBLE ESPECIALLY WITH ANY
STORMS THAT INTENSIFY AND MOVE EWD ALONG WARM/QUASISTATIONARY
FRONTAL BOUNDARY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 432 PM EDT WED JUL 17 2013
THURSDAY NIGHT THROUGH FRIDAY...A SLOW MOVING WARM FRONT WILL
CONTINUE TO LIFT FROM LAKE SUPERIOR NORTHWARD INTO ONTARIO DURING
THE EVENING HOURS AS A COLD FRONT IS PUSHED SOUTHEASTWARD OUT OF
SOUTHERN MANITOBA INTO NORTHEASTERN MN DURING THE OVERNIGHT HOURS. AT
THE SAME TIME THE UPPER LEVEL 500MB TROUGH WILL BEGIN DIGGING
SOUTHWARD INTO THE REGION. OUT AHEAD OF THE COLD FRONT A 40KT LLJ IS
EXPECTED TO DEVELOP AND REMAIN IN PLACE THROUGH THE OVERNIGHT HOURS.
THIS WILL CONTINUE TO PUMP MOISTURE INTO THE AREA. WHILE THE FORECAST
SOUNDINGS GAIN A BIT MORE MOISTURE THROUGHOUT...DRY AIR REMAINS IN
PORTIONS OF THE MID AND LOWER LEVELS...IF THIS IS NOT ALTERED BY
EARLIER CONVECTION...THEREFORE A CONTINUED WIND THREAT WILL EXIST
DURING THE EVENING AND OVERNIGHT HOURS. STRONG TO SEVERE
THUNDERSTORMS WILL BE POSSIBLE THURSDAY EVENING INTO THE OVERNIGHT
HOURS AS 0-6KM SHEAR VALUES ARE EXPECTED TO BE AROUND 40 TO 45 KNOTS
ALONG AND AHEAD OF THE COLD FRONT...WITH SHEAR VECTORS BECOMING
PERPENDICULAR TO THE FORCING. PWATS DURING THIS TIME PERIOD WILL BE
150-200 PERCENT OF NORMAL LEADING TO VERY HEAVY RAIN POTENTIAL. LATE
THURSDAY NIGHT THROUGH FRIDAY AFTERNOON THE COLD FRONT TO THE
NORTHWEST OF THE AREA WILL CONTINUE SOUTHEASTWARD PUSHING SOUTHEAST
OF THE AREA BY LATE FRIDAY AFTERNOON. FORCING ALONG AND AHEAD OF THE
COLD FRONT...ALONG WITH CONTINUED MOISTURE FLOWING INTO THE
SYSTEM...WILL KEEP AN INCREASED CHANCE FOR SHOWERS AND THUNDERSTORMS
IN THE FORECAST THROUGH FRIDAY MORNING. THE SEVERE THREAT WILL SHIFT
SOUTHEASTWARD INTO THE LOWER GREAT LAKES BY FRIDAY AFTERNOON AS THE
FRONT SHIFTS OUT OF THE AREA. THE UPPER LEVEL 500MB TROUGH WILL MOVE
DIRECTLY OVERHEAD BY FRIDAY AFTERNOON...WHICH WILL KEEP A CONTINUED
SLIGHT CHANCE OF SHOWERS AND POSSIBLY AN ISOLATED THUNDERSTORM IN THE
FORECAST...HOWEVER THE COVERAGE WILL BE GREATLY REDUCED.
FRIDAY NIGHT THROUGH SUNDAY NIGHT...FRIDAY NIGHT THE UPPER LEVEL
500MB TROUGH AXIS WILL SHIFT TO THE EAST OF THE UPPER GREAT LAKES AS
HIGH PRESSURE OVER SOUTHERN CANADA AND THE NORTHERN PLAINS BEGINS TO
BUILD INTO THE REGION. NORTHERLY FLOW ON THE EAST SIDE OF THE HIGH
WILL PUSH COOLER AND DRIER AIR IN FROM CANADA AS SHOWN BY OVERLAYING
1000-500MB RH...MSLP AND MOISTURE TRANSPORT. THE HIGH PRESSURE
SYSTEM WILL CONTINUE TO SHIFT EASTWARD BECOMING DIRECTLY OVERHEAD
SATURDAY NIGHT INTO THE DAY SUNDAY. WITH THE HIGH DIRECTLY
OVERHEAD...WINDS WILL BE LIGHT AND VARIABLE ALLOWING TEMPERATURES TO
POSSIBLY COOL INTO THE LOW AND MID 40S...ESPECIALLY OVER THE INLAND
WEST AREA. THE HIGH PRESSURE SYSTEM IS PROGGED TO REMAIN OVER THE
CWA INTO SUNDAY NIGHT.
MONDAY THROUGH WEDNESDAY...CONSIDERABLE DIFFERENCES REMAIN IN TIMING
AND STRENGTH OF UPPER LEVEL WAVES MOVING INTO THE AREA ALONG WITH
MOISTURE AND SURFACE PRESSURE FIELDS. THIS DIFFERENCE OCCURS FROM
MODEL TO MODEL AND FROM MODEL RUN TO MODEL RUN FOR THE WEATHER
PATTERN OVER THE FIRST HALF OF NEXT WEEK. WITH SUCH INCONSISTENCIES
HAVE DECIDED TO STICK WITH A CONSENSUS OF THE MODELS FOR THIS TIME
PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 146 AM EDT THU JUL 18 2013
THE MAIN FOCUS OF CONCERN FOR THIS FORECAST PERIOD WILL BE
THUNDERSTORM DEVELOPMENT ALONG/NEAR THE COLD FRONT ACROSS UPPER
MICHIGAN. EXPECT SHOWER AND THUNDERSTORM DEVELOPMENT TO BECOME A
LITTLE MORE ACTIVE OVERNIGHT ALONG THE FRONT...WITH THE BEST CHANCES
FOR SHOWERS/STORMS BEING IN IWD AND CMX. TOUGH TO PIN POINT ANY
EXACT TIMING FOR THE STORMS...BUT THE EXPECTATION IS THAT ANY STORM
WILL CREATE TORRENTIAL DOWNPOURS AND BRIEF IFR CONDTIONS. SHOULD BE
A LITTLE LULL IN PCPN TMRW MORNING INTO EARLY AFTERNOON BEFORE THE
NEXT ROUND DEVELOPS LATE THU AFTN INTO EVENING. THESE COULD END UP
BEING STRONG TO SEVERE ESPECAILLY IF THEY DEVELOP INTO A ORGANIZED
CONVECTIVE COMPLEX.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 432 PM EDT WED JUL 17 2013
WITH RELATIVELY WEAK PRES GRADIENT AND HI STABILITY OVER THE
RELATIVELY COOL LAKE WATERS...EXPECT WINDS NO HIGHER THAN 20 KTS
THIS FORECAST PERIOD. THE MAIN WEATHER CONCERN WILL BE FOG WITH A
HUMID AIRMASS DOMINATING. THIS FOG IS LIKELY TO BE MOST WIDESPREAD
ON THU NIGHT FOLLOWING SOME STRONG TO POSSIBLY SVR THUNDERSTORMS
THAT WILL FURTHER SATURATE THE MARINE LAYER. THE ARRIVAL OF DRIER
AIR ON FRI SHOULD DISSIPATE THE FOG.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...MRD
SHORT TERM...VOSS
LONG TERM...KEC
AVIATION...MRD
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS GAYLORD MI
116 AM EDT THU JUL 18 2013
.SYNOPSIS...
ISSUED AT 429 PM EDT WED JUL 17 2013
A LARGE AREA OF HIGH PRESSURE WILL CONTINUE TO BRING HOT WEATHER TO
NORTHERN MICHIGAN THROUGH THURSDAY...WITH MUGGY CONDITIONS LINGERING
THROUGH THE WORK WEEK. CHANCES FOR SHOWERS AND THUNDERSTORMS WILL
GRADUALLY INCREASE STARTING TONIGHT...AS A COLD FRONT APPROACHES THE
UPPER GREAT LAKES AND MOVES THROUGH THE REGION. A COOLER AND MORE
COMFORTABLE AIR MASS WILL SETTLE INTO MICHIGAN THIS WEEKEND.
&&
.UPDATE...
ISSUED AT 111 AM EDT THU JUL 18 2013
UPDATES THE FORECAST FOR ADDING POPS/INCREASING POPS AROUND THE
THETA-E GRADIENT NEAR THE FRONT THAT DROPPED SOUTH INTO EASTERN
UPPER. WEAKISH LLJ DOES PROVIDE CONVERGENCE OVER FAR NRN LAKE
MICHIGAN...AND THIS LLJ COULD GET A BOOST FROM THE MORE STABLE
DOME OF AIR OVER THE COOLER WATERS. LATEST HRRR SUPPORTS THIS
NOTION. ROUGHLY 08Z-14Z FOR THE PEAK TIMES FOR CONVECTION.
UPDATE ISSUED AT 1029 PM EDT WED JUL 17 2013
SPOTTY CONVECTION UPSTREAM HAS BEEN STRUGGLING TO CROSS FAR NORTHERN
LAKE MI...AND AT THE MOMENT VERY LITTLE PRECIP IS OCCURRING IN
THIS FORECAST AREA. HOWEVER...SPOTTY CONVECTION CONTINUES TO BE
GENERATED UPSTREAM...THOUGH WITH NO SIGNS OF UPSCALE GROWTH TO A
FORWARD-PROPAGATING MCS. A FEW SHRA/TSRA ARE ALSO FIRING JUST OFF
OF ARENAC/IOSCO COUNTIES.
GIVEN RADAR TRENDS IN OUR IMMEDIATE VICINITY...IT IS QUITE
TEMPTING TO START YANKING POPS OUT OF THE FORECAST LEFT AND RIGHT.
HAVE TENDED TO DIMINISH PRECIP...BUT HAVE CHOSEN NOT TO GO
OUTRIGHT DRY. WE HAVE A 25KT WESTERLY 850MB JET...HELPING TO
SUPPORT AN INCREASE IN CONVECTION IN WESTERN UPPER MI. THIS JET
DOES NOT MAKE A TON OF EASTWARD PROGRESS TONIGHT....WITH THE TIP
PUSHING EAST TOWARD MUNISING/ESC. BUT THE ELEVATED CONVECTION IT
SPAWNS SHOULD HAVE EASIER TIME CROSSING THE COOLER LAKE WATERS. SO
HAVE KEPT CHANCY POPS IN FOR A GOOD CHUNK OF NORTHERN
MI...SOUTHERN SECTIONS EXCLUDED.
IN THE MEANTIME...SKIES ARE NOT QUITE AS CLOUDY AS EARLIER
EXPECTED. BETWEEN THAT AND PRECIP...AND TEMPS ARE ALREADY A LITTLE
THAN PROGGED IN SOME (MAINLY NORTHERN) AREAS. WILL BE LOWERING MIN
TEMPS A SMIDGE WHERE APPROPRIATE.
UPDATE ISSUED AT 742 PM EDT WED JUL 17 2013
JUST KEEPING UP WITH PRECIP TRENDS AT THIS POINT...WITH HIGHER
POPS IN THE STRAITS AND OTHER SOUTHERLY SECTIONS OF EASTERN
UPPER...AND LOWER ELSEWHERE. EARLIER ACTIVITY IN WI HAD ABSOLUTELY
NO SUCCESS IN CROSSING COOL LAKE MI. WILL WAIT AND SEE IF ACTIVITY
WELL UPSTREAM IN THE MN ARROWHEAD CAN PRODUCE ENOUGH OF A COLD
POOL TO MAKE A RUN EASTWARD. BUT WITH WESTERLY 850MB AND 950MB
FLOW THRU THE NIGHT...THE SET-UP IS FAR FROM CLASSICAL FOR A
NOCTURNAL MCS TO TAKE A RUN AT US.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 429 PM EDT WED JUL 17 2013
VERY WARM AND HUMID CONDITIONS PERSIST COURTESY OF 599 DM 500 MB
HIGH SITTING ACROSS THE LOWER GREAT LAKES...WITH HEAT INDICES
RUNNING 90 TO 100 DEGREES. AS TALKED ABOUT IN MORNING DISCUSSION...
SFC DEWPOINTS HAVE MIXED OUT/DROPPED OVER PARTS OF NRN LOWER
MICHIGAN THIS AFTERNOON...MAINLY NORTH OF M-32...RESULTING IN A
WEDGE OF REDUCED INSTABILITY ACROSS THE TIP OF THE MITT INTO
EASTERN UPPER MICHIGAN. A BIT MORE INSTABILITY SOUTH OF M-72 WITH
MLCAPE VALUES IN EXCESS OF 2500 J/KG. ANOTHER AXIS OF INSTABILITY
STRETCHES UP THROUGH EASTERN WISCONSIN INTO CENTRAL UPPER
MICHIGAN.
A FEW SMALL AREAS OF STORMS HAVE ONCE AGAIN DEVELOPED NORTH AND
WEST OF THIS CWA...ONE LINE ACROSS CENTRAL AND INTO EASTERN UPPER
MICHIGAN ALONG LAKE SUPERIOR MARINE BOUNDARY. SECOND SMALL BATCH
OF STORMS IN EASTERN WISCONSIN.
TONIGHT...KEEPING AN EYE ON STORMS TO THE NORTH AS SOME STRONGER
MID LEVEL FLOW (AND INCREASED DEEP LAYER SHEAR) IS SAGGING INTO
NRN MICHIGAN...WHICH WILL AID STORM ORGANIZATION. BUT IN THE
MEANTIME...INSTABILITY DOES DWINDLE HEADING EAST AND SOUTH INTO
CHIP/MACK COUNTIES AS WELL AS THE TIP OF THE MITT...SUGGESTING ONGOING
STORMS WILL DIMINISH AS THEY TRY TO SAG INTO THIS CWA (SIMILAR TO
YESTERDAY). WILL SEE...BUT THERE IS CERTAINLY A THREAT FOR A FEW
STRONGER STORMS PRODUCING GUSTY WINDS/SMALL HAIL AND HEAVY RAIN
HEADING INTO THE EVENING FOR EASTERN UPPER MICHIGAN...WITH SOME OF
THAT REMNANT ACTIVITY ULTIMATELY SAGGING DOWN INTO NRN LOWER
MICHIGAN THIS EVENING.
MEANWHILE...THINK STORMS OVER EASTERN WISCONSIN WILL FIZZLE AS
THEY TRY TO WORK ACROSS COOLER LAKE MICHIGAN. BUT STILL THE
POSSIBILITY FOR POP-UP SHOWERS/STORMS OVER THE EASTERN/SRN COUNTIES
HEADING INTO THE EVENING...BUT WITH A LOWER RISK FOR STRONG
STORMS (MORE OF A PULSE TYPE THREAT).
THURSDAY...AFOREMENTIONED FRONT IS EXPECTED TO SAG INTO THE TIP OF
THE MITT REGION AND STALL OVERNIGHT THROUGH THE DAY THURSDAY. WITH
DAYTIME HEATING...THIS SHOULD SERVE AS THE FOCUS FOR ADDITIONAL
SHOWER AND THUNDERSTORM CHANCES ACROSS MUCH OF THE CWA ON THURSDAY
ALONG WITH AN INCREASED RISK FOR STRONGER STORMS AS STRONGER MID
LEVEL FLOW FURTHER INCREASES ACROSS NORTHERN MICHIGAN.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 429 PM EDT WED JUL 17 2013
BIG...AND PERHAPS WELCOMED...CHANGES ON THE WAY AS NOAM LONG-WAVE
PATTERN GOES THROUGH SOME SIGNIFICANT REALIGNMENT...WITH CURRENT
OVERHEAD HEAT DOME YIELDING TO EXTENDED NORTHEAST NOAM/GREAT LAKES
TROUGHING THROUGH THIS WEEKEND. ABOVE WILL SEND A RATHER VIGOROUS
(FOR MID SUMMER ANYWAY) COLD FRONT RAPIDLY SOUTHEAST ACROSS THE
NORTHERN LAKES FRIDAY...USHERING IN A MUCH MORE TOLERABLE AIRMASS
FOR THE WEEKEND. SUCH AN ABRUPT CHANGE LIKELY NOT TO BE A QUIET
ONE...WITH SHOWERS AND STORMS...POSSIBLY SEVERE...THURSDAY NIGHT AND
FRIDAY. MID RANGE GUIDANCE PROGS HAVE FULL SUPPORT FROM EARLY SUMMER
TRENDS...WITH TROUGHING AND NEAR SEASONAL TEMPERATURES DOMINATING
INTO MUCH OF NEXT WEEK. FIRST AND FOREMOST...THURSDAY NIGHT AND
FRIDAY`S STORM CHANCES WILL NEED ADDRESSING...WITH LATTER CONCERNS
CENTERED MORE ON TEMPERATURE TRENDS AND ADDITIONAL SHOWER CHANCES
HEADING INTO NEXT WORK WEEK.
PATTERN RECOGNITION ACTUALLY DECREASING THE CONFIDENCE LEVEL ON
THURSDAY NIGHT AND FRIDAY`S SHOWER AND STORM COVERAGE...LET ALONE
SEVERE POTENTIAL. FROM A CONCEPTUAL MODEL...CONDITIONS LOOK
PRETTY RIPE FOR RATHER WIDESPREAD SHOWERS AND STORMS FOR BOTH
PERIODS...WITH MID AND UPPER JET`S SPREADING SOUTH...HELPING ENTICE
FURTHER LIFT ON AN ALREADY RATHER BUOYANT AND MOIST AIRMASS.
GENERATION OF A RATHER VIGOROUS NORTHERN PLAINS COLD FRONT LATER
THURSDAY...AND ITS EVENTUAL PASSAGE ACROSS OUR AREA FRIDAY
AFTERNOON...ONE WOULD THINK WOULD ONLY HELP THE CAUSE. QUESTION NOT
OF ONE IF THUNDERSTORMS WILL FORM...BUT RATHER WHERE THEY FORM AND
THEIR EVENTUAL PATH. LATE THURSDAY HAS MCS DEVELOPMENT WRITTEN ALL
OVER IT....WITH WEAK AND NORTHWARD RETREATING WARM FRONT
INCREASINGLY BISECTED BY DEVELOPING 40+ KNOT LOW LEVEL JET...ALL THE
WHILE POCKET OF 2K-3K J/KG ML CAPE EXPANDS JUST SOUTH OF THIS FRONT
BY LATER THURSDAY AFTERNOON. RECENT GUIDANCE TRENDS SUGGEST MAX
COLLOCATION OF THE ABOVE EXPECTED ACROSS NORTHERN MINNESOTA/FAR
SOUTHERN ONTARIO/AND INTO WESTERN LAKE SUPERIOR WHERE AFTERNOON
STORMS WILL LIKELY QUICKLY CONGEAL INTO AN MCS THURSDAY EVENING.
WHAT HAPPENS THEREAFTER IS WHEN CONFIDENCE REALLY BEGINS TO WAVER.
FOLLOWING BEST MASS CONVERGENCE ON NOSE OF SLOWLY VEERING LOW LEVEL
JET SUPPORTS THIS WELL ORGANIZED...AND POTENTIALLY DAMAGING WIND
PRODUCING...MCS TRACKING ACROSS LAKE SUPERIOR AND SOUTHERN ONTARIO.
THIS...HOWEVER ...IS DEFINITELY NOT WRITTEN IN STONE JUST YET...WITH
A PROPENSITY FOR THESE SYSTEMS TO PIVOT TOWARDS BETTER INSTABILITY....
WHICH BY OVERNIGHT THURSDAY...STRETCHES RIGHT ACROSS NORTHERN
MICHIGAN. REALLY LIKE INHERITED FORECAST THAT KINDA SPLITS THE
DIFFERENCE BETWEEN THESE TWO IDEAS...WITH HIGHEST LIKELIHOOD OF ANY
IMPACTS ACROSS THE FAR NORTH. THIS PERIOD WILL CONTINUE TO BE
MONITORED CLOSELY AS COUPLING OF DEEP UNIDIRECTIONAL SHEAR (0-6KM
SHEAR MAGNITUDE IN EXCESS OF 45 KNOTS ACROSS THE NORTH) AND RATHER
UNSTABLE OVERNIGHT AIRMASS COULD POSSIBLE LEAD TO A RATHER
SUBSTANTIAL DAMAGING WIND EVENT. PER THE USUAL...FRIDAY`S SEVERE
WEATHER CHANCES TREMENDOUSLY DICTATED BY WHAT HAPPENS THURSDAY
NIGHT. CONCEPTUAL MODEL DEFINITELY SUPPORTS MORE SEVERE STORM
POTENTIAL WITH DEEP LAYER CONVERGENCE TIED TO STRONG COLD FRONT AS
IT PLOWS SOUTHEAST ACROSS OUR AREA. FOR ONCE...FRONTAL TIMING LOOKS
NICELY COUPLED WITH FAVORED DIURNALLY DRIVEN INSTABILITY CYCLE...
WITH MULTI-GUIDANCE PROGS SUGGESTING MAX CONVERGENCE SLIPPING ACROSS
NORTHERN MICHIGAN DURING THE AFTERNOON HOURS. DECENT POCKET OF MID
AND UPPER LEVEL SUPPORT COLLOCATED WITH THIS LOW LEVEL CONVERGENCE
AXIS...WITH RER UPPER JET DYNAMICS...40 TO 50 KNOTS OF MID LEVEL
FLOW...AND SOME UPWARD QG SUPPORT ALONG SHORTWAVE TROUGH. COMBINE
ALL THE ABOVE WITH AMPLE PRE-FRONTAL MOISTURE (PWAT VALUES WELL OVER
1.5 INCHES) AND CONDITIONS APPEAR VERY FAVORABLE FOR ADDITIONAL
THUNDERSTORM ACTIVITY...WITH SEVERE WEATHER A DISTINCT POSSIBILITY.
PLENTY OF RED FLAGS TO CONSIDER...HOWEVER...ALL TIED TO LINGERING
EFFECTS OF THURSDAY NIGHT ACTIVITY. DOES POST MCS AIRMASS HAVE AN
ADEQUATE TIME TO DESTABILIZE? WILL MCS INDUCED SUBSIDENCE OVERCOME
INCREASINGLY FAVORABLE SYNOPTIC SUPPORT? EVEN SOME OF THE NORTHERN
MCS SOLUTIONS FOR THURSDAY NIGHT SUGGEST OUR AREA BECOMING CAPPED AS
PRE-FRONTAL WAA STRENGTHENS FRIDAY...WITH STORMS FIRING VERY LATE
AND JUST TO OUR SOUTH. PLENTY TO PONDER IN THE COMING DAYS...AND
WILL SIMPLY KEEP A RATHER GENERIC FORECAST FOR NOW...WHILE MAINTAINING
HEIGHTENED AWARENESS OF SEVERE WEATHER POTENTIAL THROUGH OUR
HAZARDOUS WEATHER OUTLOOK AND BRIEFING.
GREAT AGREEMENT COLD FRONT WILL EXIT QUICKLY FRIDAY EVENING...
ENDING THE SHOWER AND STORM THREAT. POST-FRONTAL AIRMASS LOOKS
REFRESHING...WITH RATHER VIGOROUS CAA DROPPING HIGH TEMPERATURES
INTO THE UPPER 60S AND 70S FOR THE WEEKEND. DESPITE OVERHEAD MID
LEVEL TROUGHING...SURFACE HIGH PRESSURE AND A RATHER DRY AIRMASS
SHOULD PREVENT ANY AFTERNOON SHOWER DEVELOPMENT. PLENTY OF
UNCERTAINTY HEADING INTO NEXT WORK WEEK...CENTERED ON HARD TO TIME
WAVE (WAVES?). PERIOD WILL FEATURE SOME "CHANCY" WORDING...ALTHOUGH
LIKELY WILL BE OVERDONE COMPARED TO REALITY. PLENTY OF TIME TO
REVISIT THIS...WITH MUCH PRIORITY SET ON EARLIER PERIOD
WEATHER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 115 AM EDT THU JUL 18 2013
SOME FOG AT MBL LATE TONIGHT. TSRA CHANCES INCREASING THURSDAY
EVENING...ESPECIALLY AT PLN. LLWS LATE THU EVENING TVC/MBL.
CONTINUED HOT/HUMID.
SHRA/TSRA GENERATED IN UPPER MI CONTINUE TO WEAKEN AS THEY MOVE
ESE-WARD. AM EXPECTING WEAKISH LLJ IN WESTERLY FLOW...POKING INTO
FAR NRN LAKE MICHIGAN TO IGNITE NEW SHOWERS/STORMS AND RIDE INTO
PLN AND POSSIBLY APN SHORTLY AFTER DAYBREAK. FOR NOW...GIVEN LOW
CONFIDENCE...WILL HAVE VCSH. DO HAVE SOME MVFR FOG FOR A FEW
HOURS AT MBL. SOME CU AGAIN ON THURSDAY... BUT BEST CHANCE FOR
RAIN WILL WAIT FOR THE NIGHTTIME HOURS.
EXPECT AN ORGANIZED AREA OF STRONG TSRA TO DEVELOP TO OUR NW LATE
THURSDAY AFTERNOON. WHERE IT GOES IS UNCERTAIN...BUT THE MOST
LIKELY COURSE IS EASTWARD ACROSS SUPERIOR AND UPPER MI. THUS HAVE
LATE EVENING TSRA ONLY AT PLN FOR NOW.
LIGHT WINDS TONIGHT...A SW BREEZE THURSDAY. MBL/TVC WILL DECOUPLE
JUST ENOUGH THU EVENING TO ALLOW LLWS TO DEVELOP...WHEREAS PLN
WILL JUST STAY GUSTY.
&&
.MARINE...
ISSUED AT 429 PM EDT WED JUL 17 2013
RELATIVELY LIGHTER WINDS WILL PREVAIL ON THE LAKES TONIGHT INTO
THURSDAY WITH NO MARINE HEADLINES ANTICIPATED. STRONGER WEST TO
SOUTHWEST WINDS DEVELOP THURSDAY NIGHT INTO FRIDAY AHEAD OF A
STRONG COLD FRONT THAT WILL PRESS THROUGH THE REGION ON FRIDAY.
SMALL CRAFT ADVISORIES MAY BE NEEDED FOR SOME NEARSHORE AREAS
DURING THAT TIME.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...HEAT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR MIZ016>036-041-042.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...SD
SYNOPSIS...TL
SHORT TERM...BA
LONG TERM...MB
AVIATION...JZ
MARINE...BA
AREA FORECAST DISCUSSION
NWS DULUTH MN
304 PM CDT THU JUL 18 2013
.SHORT TERM.../THROUGH TONIGHT/
THE FOCUS IS ON THE THREAT OF SEVERE THUNDERSTORMS THROUGH THIS
EVENING. THE STORM PREDICTION CENTER HAS POSTED ALL OF THE
NORTHLAND IN AT LEAST A SLIGHT RISK OF SEVERE THUNDERSTORMS...AND
A MODERATE RISK ACROSS THE SOUTHERN HALF OF THE FORECAST AREA.
LARGE HAIL AND HEAVY RAIN MAY BE THE INITIAL MAIN THREATS AND THEN
QUICKLY TRANSITIONING TO A DAMAGING WIND THREAT. THE
MODELS...ESPECIALLY THE HIGH RESOLUTION HRRR AND NCEP WRF
SIMULATED REFLECTIVITY RUNS...HAVE BEEN INDICATING SUPERCELL
THUNDERSTORMS WILL LIKELY DEVELOP IN NW AND NORTH CENTRAL
MINNESOTA LATE THIS AFTERNOON OR EARLY THIS EVENING...AND THEN
CONGEAL INTO A LINE OF STORMS THAT SWEEP THROUGH THE NORTHLAND
THIS EVENING. A SEVERE THUNDERSTORM WATCH WILL LIKELY BE ISSUED
WITHIN THE NEXT HOUR OR SO.
THIS AFTERNOON AND EVENING...MUCH OF THE NORTHLAND HAS HOT AND
MUGGY WEATHER WITH GUSTY SW WINDS AS A FRONT STRETCHES ACROSS
WESTERN ONTARIO TO A LOW IN THE NORTHERN RED RIVER VALLEY. A
STRONG COLD FRONT EXTENDS FROM SW FROM THE LOW THROUGH THE CENTRAL
DAKOTAS. MOST OF THE NORTHLAND...SAVE FOR THE FAR NORTH AND OVER
THE LAKE...HAS DEVELOPED AMPLE SURFACE BASED CAPE UP TO AROUND
3500 J/KG...MAXIMIZED ACROSS THE S AND SW FORECAST AREA. THERE IS
LITTLE IF ANY INHIBITION. DEEP LAYER (0-6KM) WIND SHEAR OF 30 TO
50 KNOTS HAS DEVELOPED...WITH THE HIGHEST SHEAR ACROSS THE
NORTHERN HALF OF THE FORECAST AREA. PRECIPITABLE WATER VALUES ARE
AROUND 1.75 TO 2 INCHES. THERE SHOULD BE INCREASING CHANCES OF
SHOWERS AND STORMS ACROSS THE FORECAST AREA THROUGH THE REST OF
THE AFTERNOON...BUT THE FOCUS WILL BE ON THE WESTERN FORECAST AREA
WHERE THE MODELS HAVE BEEN INDICATING THUNDERSTORMS...LIKELY AT
FIRST SUPERCELLS...WILL DEVELOP IN NW AND NORTH CENTRAL MINNESOTA
LATE THIS AFTERNOON NEAR THE LOW PRESSURE SYSTEM AND APPROACHING
COLD FRONT. CONSIDERING THE AVAILABLE CAPE...CAPE SOUNDING
PROFILES...AND DEEP LAYER WINDS...THE SUPERCELLS COULD EASILY
DEVELOP LARGE HAIL...GUSTY WINDS...AND HEAVY RAIN. A STRAY TORNADO
CANNOT BE RULED OUT. THE STORMS MAY QUICKLY CONGEAL...AS THE
MODELS SUGGEST...INTO A LINE OF STORMS WITH A TRANSITIONING THREAT
TO MAINLY DAMAGING WINDS AND HEAVY RAIN. THIS LINE AND COLD FRONT
COULD SWEEP ESE THROUGH THE REST OF NE MINNESOTA AND THEN NW
WISCONSIN PRETTY QUICKLY THIS EVENING. I ADDED WORDING TO THE
FORECAST TO INCLUDE SEVERE THUNDERSTORMS AND THE LIKELY THREATS
FOR WHEREVER MY PCPN CHANCES ARE LIKELY LATE THIS AFTERNOON
THROUGH AROUND MIDNIGHT...WHICH IS BASICALLY MY BEST GUESS ON THE
HOURLY TIMING OF THE MAIN LINE OF THUNDERSTORMS.
LATE TONIGHT...THE SEVERE WEATHER THREAT SHOULD COME TO AN END
AROUND MIDNIGHT AS THE MAIN LINE OF STORMS MOVES SE OF THE
FORECAST AREA...BUT THERE COULD BE SOME LINGERING SHOWERS AND
STORMS ACROSS THE SE FORECAST AREA NEAR THE FRONT. THERE SHOULD
ALSO BE DECREASING CHANCES OF SHOWERS AND STORMS FROM NW TO
SE...BUT I LEFT LOW CHANCES OF SHOWERS AND STORMS ACROSS MOST OF
THE FORECAST AREA SINCE A SHORTWAVE WILL LIKELY MOVE INTO THE
NORTHERN FORECAST AREA LATE TONIGHT. THIS SHORTWAVE COULD HELP
DEVELOP SOME MORE SHOWERS AND STORMS.
.LONG TERM.../FRIDAY - WEDNESDAY/
THE WEST-NORTHWEST FLOW OF COOLER AND DRIER AIR WILL BE
ESTABLISHED OVER THE FORECAST AREA BY FRIDAY MIDDAY. THERE WILL
BE SOME LINGERING SHOWERS LEFT OVER FRIDAY MORNING BEFORE ENDING
BY MIDDAY. THE WEST TO NORTHWEST FLOW WILL CONTINUE INTO SATURDAY
BUT A WEAK SHORTWAVE WILL CAUSE A POSSIBILITY OF SHOWERS ACROSS
THE REGION. THE RIDGE WILL MOVE EAST AND A RETURN FLOW OF MOISTURE
TO THE FORECAST AREA ON SUNDAY. THIS WILL CONTINUE INTO MIDWEEK
WITH WEAK SHORTWAVES PASSING THROUGH THE FLOW. THIS WILL KEEP A
CHANCE FOR PRECIP ACROSS THE FORECAST AREA FOR THE TIME PERIOD.
TEMPS WILL BE NEAR NORMAL THROUGH MOST OF THE WEEK.
&&
.AVIATION.../18Z TAF ISSUANCE/
VFR CONDITIONS WILL BE COMMON AT ALL TAFS SITES THIS AFTERNOON
EXCEPT FOR MVFR-IFR CIGS IN THUNDERSTORMS AT INL. A LINE OF STRONG
TO SEVERE THUNDERSTORMS WILL DEVELOP ALONG THE INTERNATIONAL
BORDER LATE THIS AFTERNOON AND MOVE SOUTHEAST TONIGHT ACROSS THE
TAF SITES. CIGS/VSBYS MAY DROP TO MVFR-IFR WITH LIFR CIGS POSSIBLE
IN THUNDERSTORMS. CONDITIONS WILL IMPROVE AFTER THE LINE PASSES
LATE TONIGHT AT ALL SITES. ON FRIDAY...VFR CONDITIONS WILL BE
COMMON AT ALL SITES.
&&
.POINT TEMPS/POPS...
DLH 65 78 52 70 / 60 20 10 10
INL 61 75 46 69 / 70 20 10 10
BRD 69 81 55 75 / 60 20 10 10
HYR 71 83 53 75 / 60 30 10 10
ASX 68 78 52 69 / 60 30 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...GROCHOCINSKI
LONG TERM....STEWART
AVIATION...STEWART
AREA FORECAST DISCUSSION
NWS DULUTH MN
104 PM CDT THU JUL 18 2013
.UPDATE...
THE STORM PREDICTION CENTER ISSUED A MODERATE RISK FOR A LARGE
PORTION OF THE FORECAST...MAINLY THE SOUTHERN HALF...FOR TODAY. I
UPDATED THE FORECAST THROUGH TONIGHT TO REFLECT THE BEST GUESS OF
THE TIMING AT WHICH THE EXPECTED LINE OF STORMS WILL FORM IN NW
AND NORTH CENTRAL MINNESOTA LATE THIS AFTERNOON AND THEN SWEEP
ACROSS THE NORTHLAND THROUGH THIS EVENING. THE LATEST 12Z NCEP WRF
AND RECENT HRRR REFLECTIVITY RUNS SEEM PRETTY GOOD WITH LOCATION
AND TIMING. I ALSO RAMPED UP THE WORDING IN THE HOURLY FORECAST
THROUGH THIS EVENING TO ADD WORDING THAT INCLUDED POSSIBLE SEVERE
THUNDERSTORMS...LARGE HAIL...DAMAGING WINDS...AND HEAVY RAIN FOR
WHERE I HAVE LIKELY PCPN CHANCES.
&&
.AVIATION.../18Z TAF ISSUANCE/
VFR CONDITIONS WILL BE COMMON AT ALL TAFS SITES THIS AFTERNOON
EXCEPT FOR MVFR-IFR CIGS IN THUNDERSTORMS AT INL. A LINE OF STRONG
TO SEVERE THUNDERSTORMS WILL DEVELOP ALONG THE INTERNATIONAL
BORDER LATE THIS AFTERNOON AND MOVE SOUTHEAST TONIGHT ACROSS THE
TAF SITES. CIGS/VSBYS MAY DROP TO MVFR-IFR WITH LIFR CIGS POSSIBLE
IN THUNDERSTORMS. CONDITIONS WILL IMPROVE AFTER THE LINE PASSES
LATE TONIGHT AT ALL SITES. ON FRIDAY...VFR CONDITIONS WILL BE
COMMON AT ALL SITES.
&&
.PREV DISCUSSION... /ISSUED 1021 AM CDT THU JUL 18 2013/
UPDATE...
THE FOCUS WITH THIS UPDATE IS CONVEYING THE CURRENT TRENDS OF
SHOWERS AND STORMS LATE THIS MORNING...HOW THE ACTIVITY WILL
EVOLVE THIS AFTERNOON...AND CONVEYING THE THREAT/TIMING OF LIKELY
SEVERE WEATHER ACROSS THE WESTERN AND NORTHERN FORECAST AREA LATE
THIS AFTERNOON AND THIS EVENING. THE STORM PREDICTION CENTER STILL
HAS A SLIGHT RISK OF SEVERE STORMS ACROSS THE NORTHLAND FOR TODAY
AND TONIGHT...WITH AN ENHANCED RISK OF DAMAGING WINDS. THIS
ACTIVITY WILL LIKELY OCCUR IN THE VERY LATE AFTERNOON AND THIS
EVENING WHEN SUPERCELLS FORM IN NW AND FAR NORTH CENTRAL
MINNESOTA...THEN POSSIBLY CONGEAL TO FORM A LINE OF STORMS THAT
WILL SWEEP THROUGH THE NORTHLAND WITH DAMAGING WINDS THIS
EVENING. SURFACE BASED CAPE WILL LIKELY APPROACH...IF NOT
EXCEED...3000 J/KG...DEEP LAYER SHEAR WILL BE AROUND 35 TO 45
KNOTS...AND PRECIPITABLE WATER VALUES WILL BE AROUND 1.75 TO 2
INCHES...SO THE THREAT OF LARGE HAIL AND HEAVY RAIN IS THERE TOO.
SHOWERS AND STORMS HAVE BEEN RIDING EAST ALONG THE INTERNATIONAL
BORDER THIS MORNING. IT APPEARS THIS TREND WILL CONTINUE THROUGH
AT LEAST EARLY THIS AFTERNOON BEFORE PERHAPS SUBSIDING A BIT
DURING THE MID AFTERNOON. I AM LEANING ON THE LATEST HRRR AND 00Z
NCEP WRF SIMULATED REFLECTIVITY...AS WELL AS THE 12Z NAM...FOR MY
FORECAST THROUGH TONIGHT. THESE MODELS CAPTURE THE LULL IN
ACTIVITY DURING THE MID AFTERNOON...THEN SHOWING A LINE OF
THUNDERSTORMS FORMING EITHER LATE THIS AFTERNOON OR EARLY THIS
EVENING NEAR THE WESTERN FORECAST AREA. I AM LIKING THIS IDEA. I
AT LEAST LEFT LOW PCPN CHANCES ACROSS THE ENTIRE FORECAST THROUGH
THIS AFTERNOON DUE TO THE LACK OF INHIBITION...SO I CANNOT RULE
OUT A SHOWER/STORM HERE AND THERE. THE LINE OF STRONG/SEVERE
STORMS LATE THIS AFTERNOON AND EARLY THIS EVENING SHOULD THEN MOVE
EAST AND SOUTH THROUGH THIS EVENING. I ADDED SEVERE WORDING TO THE
FORECAST ACROSS THE NORTHERN AND WESTERN FORECAST AREA. I MIGHT
HAVE TO ADD MORE WORDING WITH A LATER UPDATE...LIKE THE THREAT OF
DAMAGING WINDS...HEAVY RAIN...AND LARGE HAIL.
I ALSO INCREASED WINDS ACROSS THE SOUTHERN HALF OF THE FORECAST
AREA THROUGH THIS AFTERNOON. THE LATEST NAM12 AND SOUNDINGS
INDICATE PRETTY GOOD MIXING...SO I WOULD NOT BE SURPRISED IF SOME
AREAS SEE GUSTS IN THE 25 TO 30 MPH RANGE. I KEPT THE TEMPERATURE
FORECAST IN THE UPPER 80S AND LOW 90S...DESPITE SOME GUIDANCE
WANTING TO LOWER THE TEMPERATURES...BECAUSE THE SUNSHINE AND
MIXING SHOULD WARM UP THE SOUTHERN FORECAST AREA REALLY WELL. I
WOULD NOT BE SURPRISED IF I HAVE TO INCREASE THE TEMPERATURES EVEN
MORE DUE TO HOW QUICKLY THE SOUTH IS ALREADY WARMING THIS MORNING.
DUE TO THE HIGH HUMIDITY...THE HEAT INDICES WILL LIKELY REACH THE
95 TO 100 DEGREE RANGE ACROSS PARTS OF THE SOUTHERN HALF OF THE
FORECAST AREA THIS AFTERNOON. IT DOES NOT APPEAR THAT WE NEED A
HEAT ADVISORY AT THIS TIME...BUT SOME AREAS COULD BRIEFLY APPROACH
CRITERIA...WHICH IS A HEAT INDEX OF 100 DEGREES.
PREV DISCUSSION... /ISSUED 356 AM CDT THU JUL 18 2013/
STRONG/SEVERE STORMS EXPECTED LATER TODAY/TONIGHT...
SHORT TERM...STATIONARY FRONTAL BDRY ACROSS CWA ASSISTING WITH
CONTINUED GENERATION OF CONVECTION ACROSS NRN/CTRL TIER OF MN ZONES
EARLY THIS MORNING. INITIAL AREA OF STORMS MOVING EASTWARD OVER
WRN LAKE SUPERIOR WITH NEW DEVELOPMENT OCCURRING ACROSS NWRN KOOCH
COUNTY. FARTHER SOUTH CONVECTION NOT AS WIDESPREAD ALTHOUGH LATEST
INDICATIONS ON SPC MESOANALYSIS SHOWS DEVELOPING 85H FRONTOGENESIS
FROM ITASCA COUNTY TO SOUTH SHORE OF LAKE SUPERIOR. MAY SEE
INCREASE ALONG THIS CORRIDOR NEXT FEW HRS.
TODAY/TONIGHT...FRONTAL BDRY WILL ADVECT NORTH IN RESPONSE TO APPROACHING
COLD FRONT AND ASSOCIATED DEEPENING MID LVL SHORTWAVE. EXPECT WARM
FRONTOGENESIS TO ENHANCE AREA OF CONVECTION ACROSS THE CWA AS IT
LIFTS NORTH THIS MORNING. WELL ESTABLISHED WARM SECTOR SHOULD
COVER A LARGE PART OF CWA BY MIDDAY. THIS WILL YIELD MAX TEMPS
ABOVE GUIDANCE AGAIN WITH BRISK SWRLY FLOW IN BDRY LYR WITH
CONSIDERABLE GUSTS DURING THE AFTN AHEAD OF FRONT. GENERAL
CONSENSUS AMONG HI RES MDLS...ALBEIT SOME DIFFERENCES IN
TIMING...IS THAT AN INCREASINGLY INTENSE LINE OF CONVECTION WILL
ORGANIZE JUST WEST OF THE CWA MID/LATE AFTERNOON AND PLOW
SOUTHEASTWARD UNDER AMPLIFYING MID LVL TROF. SBCAPES AHEAD OF
FRONT WILL RANGE FROM 4000 TO 4500 J/KG AND EFFECTIVE SHEAR SHOULD
INCREASE TO 40/45KTS. THESE VALUES WILL GENERATE A LINE OF
STRONG/SVR STORMS WITH INCREASING POTENTIAL OF CONSIDERABLE WIND
DAMAGE AND HAIL. MAY SEE LINE EVOLVE INTO AN MCS AS IT RIDES SE
WITH SOME INDICATION IN DIFFLUENT THICKNESS FIELD THAT CORE OF
CONVECTION MAY TREND MORE SOUTH TOWARDS LWR ST CROIX VALLEY BY 12Z.
TOMORROW...INITIAL COLD FRONT WILL MOVE SOUTH OF CWA BY MID
MORNING. A SECONDARY FRONT...INDICATED IN LOW LVL THETAE
FIELDS...WILL MOVE ACROSS MN ZONES IN THE LATE MORNING/AFTN HRS.
GUSTY WINDS AND LOWERING HUMIDITY WILL RESULT HAVE KEPT INHERITED
DRY FCST FOR AFTN WITH IDEA THE SUFFICIENT MOISTURE WILL NOT BE
AVAILABLE BY AFTERNOON. SUSPECT THAT A FEW RW MAY TRY TO POP IN
AFTN INSTABILITY UNDER STEEPENING LAPSE RATES.
FRIDAY NIGHT THROUGH WEDNESDAY.
THIS FRIDAY NIGHT THROUGH WEDNESDAY TIME WILL FEATURE CHANCES FOR
SHOWERS/STORMS FOR MOST PERIODS...WITH A FAST WEST-NORTHWEST FLOW
ALOFT BRINGING PERIODIC SHORTWAVES THROUGH AND WITH A BAROCLINIC
ZONE REMAINING OVER/NEAR THE AREA.
COLD AIR ADVECTION WILL CONTINUE FRIDAY NIGHT AS HIGH PRESSURE
BUILDS INTO THE REGION. WE WENT DRY FRIDAY NIGHT...ALTHOUGH A FEW
MODELS SUGGEST SOME SHOWERS MAY LINGER INTO THE EVENING.
SEVERAL MODELS SHOW SOME LIGHT PRECIP POSSIBLE OVER OUR SOUTHERN CWA
ON SATURDAY DUE TO A WEAK WAVE AND TIGHT THERMAL GRADIENT. WE HAVE
SLIGHT CHANCE POPS ACROSS OUR SOUTHERN CWA BOTH SATURDAY AND
SATURDAY NIGHT.
THE SURFACE HIGH IS EXPECTED TO SLIDE EAST OF THE REGION SATURDAY
NIGHT INTO SUNDAY WITH A RETURN FLOW AND FAST WEST-NORTHWEST FLOW
ALOFT BRINGING FAST MOVING SHORTWAVES OVER/NEAR THE CWA. WE WILL
HAVE SMALL CHANCES FOR SHOWERS/STORMS OVER MUCH OF THE NORTHLAND
SUNDAY/SUNDAY NIGHT...ALTHOUGH THE PRECIP DOES NOT LOOK TO BE
PARTICULARLY WIDESPREAD OR HEAVY.
WE HAVE HIGHER POPS FOR MONDAY-TUESDAY AS A SURFACE LOW/FRONT
AFFECTS THE NORTHLAND.
WE EXPECT HIGHS SATURDAY IN THE UPPER SIXTIES TO MID
SEVENTIES...WITH THEM WARMING TO THE MID SEVENTIES TO LOWER EIGHTIES
BY MONDAY LASTING INTO WEDNESDAY.
&&
.POINT TEMPS/POPS...
DLH 65 78 52 70 / 60 20 10 10
INL 61 75 46 69 / 70 20 10 10
BRD 69 81 55 75 / 60 20 10 20
HYR 71 83 53 75 / 60 30 10 20
ASX 68 78 52 69 / 60 30 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...GROCHOCINSKI
LONG TERM....STEWART
AVIATION...STEWART
AREA FORECAST DISCUSSION
NWS DULUTH MN
1021 AM CDT THU JUL 18 2013
.UPDATE...
THE FOCUS WITH THIS UPDATE IS CONVEYING THE CURRENT TRENDS OF
SHOWERS AND STORMS LATE THIS MORNING...HOW THE ACTIVITY WILL
EVOLVE THIS AFTERNOON...AND CONVEYING THE THREAT/TIMING OF LIKELY
SEVERE WEATHER ACROSS THE WESTERN AND NORTHERN FORECAST AREA LATE
THIS AFTERNOON AND THIS EVENING. THE STORM PREDICTION CENTER STILL
HAS A SLIGHT RISK OF SEVERE STORMS ACROSS THE NORTHLAND FOR TODAY
AND TONIGHT...WITH AN ENHANCED RISK OF DAMAGING WINDS. THIS
ACTIVITY WILL LIKELY OCCUR IN THE VERY LATE AFTERNOON AND THIS
EVENING WHEN SUPERCELLS FORM IN NW AND FAR NORTH CENTRAL
MINNESOTA...THEN POSSIBLY CONGEAL TO FORM A LINE OF STORMS THAT
WILL SWEEP THROUGH THE NORTHLAND WITH DAMAGING WINDS THIS
EVENING. SURFACE BASED CAPE WILL LIKELY APPROACH...IF NOT
EXCEED...3000 J/KG...DEEP LAYER SHEAR WILL BE AROUND 35 TO 45
KNOTS...AND PRECIPITABLE WATER VALUES WILL BE AROUND 1.75 TO 2
INCHES...SO THE THREAT OF LARGE HAIL AND HEAVY RAIN IS THERE TOO.
SHOWERS AND STORMS HAVE BEEN RIDING EAST ALONG THE INTERNATIONAL
BORDER THIS MORNING. IT APPEARS THIS TREND WILL CONTINUE THROUGH
AT LEAST EARLY THIS AFTERNOON BEFORE PERHAPS SUBSIDING A BIT
DURING THE MID AFTERNOON. I AM LEANING ON THE LATEST HRRR AND 00Z
NCEP WRF SIMULATED REFLECTIVITY...AS WELL AS THE 12Z NAM...FOR MY
FORECAST THROUGH TONIGHT. THESE MODELS CAPTURE THE LULL IN
ACTIVITY DURING THE MID AFTERNOON...THEN SHOWING A LINE OF
THUNDERSTORMS FORMING EITHER LATE THIS AFTERNOON OR EARLY THIS
EVENING NEAR THE WESTERN FORECAST AREA. I AM LIKING THIS IDEA. I
AT LEAST LEFT LOW PCPN CHANCES ACROSS THE ENTIRE FORECAST THROUGH
THIS AFTERNOON DUE TO THE LACK OF INHIBITION...SO I CANNOT RULE
OUT A SHOWER/STORM HERE AND THERE. THE LINE OF STRONG/SEVERE
STORMS LATE THIS AFTERNOON AND EARLY THIS EVENING SHOULD THEN MOVE
EAST AND SOUTH THROUGH THIS EVENING. I ADDED SEVERE WORDING TO THE
FORECAST ACROSS THE NORTHERN AND WESTERN FORECAST AREA. I MIGHT
HAVE TO ADD MORE WORDING WITH A LATER UPDATE...LIKE THE THREAT OF
DAMAGING WINDS...HEAVY RAIN...AND LARGE HAIL.
I ALSO INCREASED WINDS ACROSS THE SOUTHERN HALF OF THE FORECAST
AREA THROUGH THIS AFTERNOON. THE LATEST NAM12 AND SOUNDINGS
INDICATE PRETTY GOOD MIXING...SO I WOULD NOT BE SURPRISED IF SOME
AREAS SEE GUSTS IN THE 25 TO 30 MPH RANGE. I KEPT THE TEMPERATURE
FORECAST IN THE UPPER 80S AND LOW 90S...DESPITE SOME GUIDANCE
WANTING TO LOWER THE TEMPERATURES...BECAUSE THE SUNSHINE AND
MIXING SHOULD WARM UP THE SOUTHERN FORECAST AREA REALLY WELL. I
WOULD NOT BE SURPRISED IF I HAVE TO INCREASE THE TEMPERATURES EVEN
MORE DUE TO HOW QUICKLY THE SOUTH IS ALREADY WARMING THIS MORNING.
DUE TO THE HIGH HUMIDITY...THE HEAT INDICES WILL LIKELY REACH THE
95 TO 100 DEGREE RANGE ACROSS PARTS OF THE SOUTHERN HALF OF THE
FORECAST AREA THIS AFTERNOON. IT DOES NOT APPEAR THAT WE NEED A
HEAT ADVISORY AT THIS TIME...BUT SOME AREAS COULD BRIEFLY APPROACH
CRITERIA...WHICH IS A HEAT INDEX OF 100 DEGREES.
&&
.PREV DISCUSSION... /ISSUED 642 AM CDT THU JUL 18 2013/
AVIATION...12Z TAFS
A WARM FRONT DRAPED ACROSS NORTHERN MINNESOTA WAS THE FOCUS FOR
SHOWERS AND STORMS OVERNIGHT...AND WILL CONTINUE TO BE THROUGH
MUCH OF THE MORNING. AREAS OF FOG HAVE FORMED...BUT WAS ALREADY
LIFTING AT KHIB WHICH WAS 1/4SM IN FG EARLIER. FOG WAS OCCURRING
AROUND LAKE SUPERIOR...AND COULD CREEP OVER THE HILL IN DULUTH AND
AFFECT THE KDLH TAF FOR A PERIOD AS WINDS WILL BE ONSHORE FOR A
TIME TODAY. WE EXPECT MVFR OR BRIEF IFR CONDITIONS IN FOG EARLY THIS
MORNING...THEN THROUGH THE DAY IN ANY SHOWERS/STORMS.
A STRONGER SHORTWAVE WILL MOVE IN FROM THE NORTHWEST LATER TODAY
INTO TONIGHT...AND PUSH A COLD FRONT THROUGH THE REGION.
ADDITIONAL THUNDERSTORMS WILL FORM AS THIS FEATURE MOVES
THROUGH...AND SOME OF THE STORMS COULD BE SEVERE PRODUCING LARGE
HAIL AND DAMAGING WINDS. SOME ADDITIONAL STORMS WILL BE POSSIBLE
BEHIND THE FRONT AS WELL...MAINLY AFFECTING FAR NORTHERN AREAS.
GUSTY SOUTH/SOUTHWEST WINDS CAN BE EXPECTED TODAY...ESPECIALLY BY
LATE MORNING/EARLY AFTERNOON ONCE MIXING DEEPENS.
PREV DISCUSSION... /ISSUED 356 AM CDT THU JUL 18 2013/
.STRONG/SEVERE STORMS EXPECTED LATER TODAY/TONIGHT...
SHORT TERM...STATIONARY FRONTAL BDRY ACROSS CWA ASSISTING WITH
CONTINUED GENERATION OF CONVECTION ACROSS NRN/CTRL TIER OF MN ZONES
EARLY THIS MORNING. INITIAL AREA OF STORMS MOVING EASTWARD OVER
WRN LAKE SUPERIOR WITH NEW DEVELOPMENT OCCURRING ACROSS NWRN KOOCH
COUNTY. FARTHER SOUTH CONVECTION NOT AS WIDESPREAD ALTHOUGH LATEST
INDICATIONS ON SPC MESOANALYSIS SHOWS DEVELOPING 85H FRONTOGENESIS
FROM ITASCA COUNTY TO SOUTH SHORE OF LAKE SUPERIOR. MAY SEE
INCREASE ALONG THIS CORRIDOR NEXT FEW HRS.
TODAY/TONIGHT...FRONTAL BDRY WILL ADVECT NORTH IN RESPONSE TO APPROACHING
COLD FRONT AND ASSOCIATED DEEPENING MID LVL SHORTWAVE. EXPECT WARM
FRONTOGENESIS TO ENHANCE AREA OF CONVECTION ACROSS THE CWA AS IT
LIFTS NORTH THIS MORNING. WELL ESTABLISHED WARM SECTOR SHOULD
COVER A LARGE PART OF CWA BY MIDDAY. THIS WILL YIELD MAX TEMPS
ABOVE GUIDANCE AGAIN WITH BRISK SWRLY FLOW IN BDRY LYR WITH
CONSIDERABLE GUSTS DURING THE AFTN AHEAD OF FRONT. GENERAL
CONSENSUS AMONG HI RES MDLS...ALBEIT SOME DIFFERENCES IN
TIMING...IS THAT AN INCREASINGLY INTENSE LINE OF CONVECTION WILL
ORGANIZE JUST WEST OF THE CWA MID/LATE AFTERNOON AND PLOW
SOUTHEASTWARD UNDER AMPLIFYING MID LVL TROF. SBCAPES AHEAD OF
FRONT WILL RANGE FROM 4000 TO 4500 J/KG AND EFFECTIVE SHEAR SHOULD
INCREASE TO 40/45KTS. THESE VALUES WILL GENERATE A LINE OF
STRONG/SVR STORMS WITH INCREASING POTENTIAL OF CONSIDERABLE WIND
DAMAGE AND HAIL. MAY SEE LINE EVOLVE INTO AN MCS AS IT RIDES SE
WITH SOME INDICATION IN DIFFLUENT THICKNESS FIELD THAT CORE OF
CONVECTION MAY TREND MORE SOUTH TOWARDS LWR ST CROIX VALLEY BY 12Z.
TOMORROW...INITIAL COLD FRONT WILL MOVE SOUTH OF CWA BY MID
MORNING. A SECONDARY FRONT...INDICATED IN LOW LVL THETAE
FIELDS...WILL MOVE ACROSS MN ZONES IN THE LATE MORNING/AFTN HRS.
GUSTY WINDS AND LOWERING HUMIDITY WILL RESULT HAVE KEPT INHERITED
DRY FCST FOR AFTN WITH IDEA THE SUFFICIENT MOISTURE WILL NOT BE
AVAILABLE BY AFTERNOON. SUSPECT THAT A FEW RW MAY TRY TO POP IN
AFTN INSTABILITY UNDER STEEPENING LAPSE RATES.
FRIDAY NIGHT THROUGH WEDNESDAY.
THIS FRIDAY NIGHT THROUGH WEDNESDAY TIME WILL FEATURE CHANCES FOR
SHOWERS/STORMS FOR MOST PERIODS...WITH A FAST WEST-NORTHWEST FLOW
ALOFT BRINGING PERIODIC SHORTWAVES THROUGH AND WITH A BAROCLINIC
ZONE REMAINING OVER/NEAR THE AREA.
COLD AIR ADVECTION WILL CONTINUE FRIDAY NIGHT AS HIGH PRESSURE
BUILDS INTO THE REGION. WE WENT DRY FRIDAY NIGHT...ALTHOUGH A FEW
MODELS SUGGEST SOME SHOWERS MAY LINGER INTO THE EVENING.
SEVERAL MODELS SHOW SOME LIGHT PRECIP POSSIBLE OVER OUR SOUTHERN CWA
ON SATURDAY DUE TO A WEAK WAVE AND TIGHT THERMAL GRADIENT. WE HAVE
SLIGHT CHANCE POPS ACROSS OUR SOUTHERN CWA BOTH SATURDAY AND
SATURDAY NIGHT.
THE SURFACE HIGH IS EXPECTED TO SLIDE EAST OF THE REGION SATURDAY
NIGHT INTO SUNDAY WITH A RETURN FLOW AND FAST WEST-NORTHWEST FLOW
ALOFT BRINGING FAST MOVING SHORTWAVES OVER/NEAR THE CWA. WE WILL
HAVE SMALL CHANCES FOR SHOWERS/STORMS OVER MUCH OF THE NORTHLAND
SUNDAY/SUNDAY NIGHT...ALTHOUGH THE PRECIP DOES NOT LOOK TO BE
PARTICULARLY WIDESPREAD OR HEAVY.
WE HAVE HIGHER POPS FOR MONDAY-TUESDAY AS A SURFACE LOW/FRONT
AFFECTS THE NORTHLAND.
WE EXPECT HIGHS SATURDAY IN THE UPPER SIXTIES TO MID
SEVENTIES...WITH THEM WARMING TO THE MID SEVENTIES TO LOWER EIGHTIES
BY MONDAY LASTING INTO WEDNESDAY.
&&
.POINT TEMPS/POPS...
DLH 90 66 78 52 / 40 60 20 10
INL 80 60 75 46 / 80 60 20 10
BRD 92 69 81 55 / 40 60 20 10
HYR 92 71 83 53 / 50 60 30 10
ASX 89 67 78 52 / 50 60 30 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...GROCHOCINSKI
LONG TERM....STEWART
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
1223 PM CDT THU JUL 18 2013
.MESOSCALE UPDATE...SHOWERS AND THUNDERSTORMS INCREASING IN COVERAGE
ACROSS NORTHERN PART OF AREA IN ASSOCIATION WITH WAVE WHICH CONTINUES
TO MOVE WEST INTO FORECAST AREA. HAVE UPDATED (AGAIN) TO INCREASE
POPS TO 50-60 RANGE AND WORD SCATTERED/NUMEROUS ACROSS NORTHERN
THIRD OF FORECAST AREA. STILL CONCERNED ABOUT POTENTIAL FOR STRONG
AND A FEW SEVERE STORMS WEST OF CURRENT ACTIVITY GIVEN SPC
MESOANALYSIS ALREADY SHOWING SBLI OF -9...20-25 OF EFFECTIVE
SHEAR...AND THINNING CLOUDS RESULTING IN INCREASED DIURNAL HEATING
AHEAD OF ACTIVITY. ALSO LOCAL WET MICORBURST COMPOSITE PARAMETER
SHOWN BY LATEST RUC TO BE MAXING OUT OVER ARKLAMISS REGION LATER THIS
AFTERNOON. HENCE EXPECT ACTIVITY TO CONTINUE TO EXPAND IN COVERAGE
AND GRADUALLY INCREASE IN INTENSITY AS IT MOVES/PROPAGATES W/SW NEXT
SEVERAL HOURS.
FARTHER SOUTH...DIVERGENT LOW LEVEL FLOW IN WAKE OF MORNING MCS
RESULTING IN DISSIPATION OF SHOWERS. HOWEVER...SITUATION MAY EVOLVE
INTO MORE FAVORABLE SETUP DEPENDING ON AIRMASS RECOVERY THROUGH THE
AFTERNOON. WILL KEEP CHC POPS/WORDING FOR NOW.
&&
.AVIATION...
SHOWER AND THUNDERSTORM COMPLEX THAT MOVED THROUGH ERN
SITES EARLIER THIS MRNG HAS NOW PUSHED IN SE/CNTRL AND SC AREAS OF
MS IMPACTING KHBG AND KJAN/KHKS. KHBG IS LIFR AS OF 14Z WITH LOW
VISIBILITY DUE TO TSRA. TSRA WILL WEAKEN OVER NEXT HOUR AND RA WILL
END ALL TOGETHER THROUGH 1530Z WITH FLIGHT CATS IMPROVING TO VFR.
EXPECT A RETURN OF SCATTERED SHRA/TSRA NEAR KHBG THIS AFTN AS ATMOS
BECOMES UNSTABLE ONCE AGAIN. VFR -RA NEAR KJAN/KHKS AS OF 14Z WILL
LIGHTEN THROUGH 15-16Z WITH CLOUD DECKS BECMG SCT THROUGH AFTN WITH
MORE TSRA POSSIBLE BY 18-19Z. W MS/NE LA NOT TOUCHED BY COMPLEX WILL
BE MORE FAVORED REGION FOR GREATER COVERAGE OF AFTN TSRA. SOME TSRA
COULD BE STRONG TO SEVERE. ALL SHRA/TSRA ACTIVITY EXPECTED TO
DIMINISH THROUGH MID EVENING HOURS. WILL MONITOR FOG POTENTIAL
OVRNGT GIVEN TODAYS RAINFALL AND HAVE ALREADY PLACED MVFR BASED ON
VIS IN ERN LOCATIONS. /ALLEN/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 90 69 92 70 / 40 24 32 26
MERIDIAN 90 69 92 68 / 40 24 31 26
VICKSBURG 90 68 92 68 / 40 24 31 26
HATTIESBURG 90 70 92 70 / 40 24 40 26
NATCHEZ 90 69 92 69 / 40 24 39 26
GREENVILLE 94 71 93 72 / 44 24 30 26
GREENWOOD 91 70 93 70 / 55 24 30 26
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
AEG/JA
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
827 AM CDT THU JUL 18 2013
.UPDATE...
UPDATED GRIDS TO RAISE POPS IN SOUTH CENTRAL/SE MS AND LOWER THEM
ACROSS THE CENTRAL AND NORTH FOR THE AM.
&&
.SHORT TERM...
MCS CONTINUES TO FORWARD PROPAGATE WSW ACROSS SOUTH CENTRAL AND SE MS
TOWARD THE FLORIDA PARISHES OF LA. OVERALL ACTIVITY HAS SHOWN A
MARKED DECREASE IN INTENSITY OVER THE LAST 6O MINUTES...AND TRENDS AND
HRRR WOULD INDICATE THIS IS SHOULD CONTINUE. HAVE ADJUSTED THE
MORNING POPS TO SHOW CATEGORICAL IN SC/SE WHERE RAIN IS CURRENTLY
ONGOING...AND REDUCED FARTHER TO THE ALONG AND N OF I-20 WHERE
PRECIPITATION AREA HAS SUBSTANTIALLY DIMINISHED.
BIG QUESTION FOR REST OF DAY IS WHAT HAPPENS IN WAKE OF MORNING
ACTIVITY. SATELLITE SHOWS WHAT LOOKS TO BE ANOTHER WAVE CURRENTLY
MOVING ACROSS N AL AND MID TN. A FEW SHRA/TSRA ARE ASSOCIATED WITH THIS
FEATURE. DEPENDING ON HOW MUCH CLOUDS WITH CURRENT MCS THIN...THIS WAVE
COULD REFIRE ACTIVITY ACROSS NORTHERN AREAS THIS AFTERNOON. LZK
SOUNDING WOULD IMPLY ANY ACTIVITY THAT WOULD DEVELOP IN THIS AREA
COULD BE QUITE ROBUST WITH MICROBURST POTENTIAL. FARTHER S ADDITIONAL
DEVELOPMENT COULD TAKE PLACE ACROSS SW MS AND EC LA ALONG RESIDUAL
OUTFLOW. HRRR SHOWS THIS OCCURRING...BUT AGAIN LOW CONFIDENCE
SOLUTION AS IT DEPENDS ON HOW DEBRIS AND OUTFLOW BEHAVE NEXT FEW
HOURS. FOR NOW HAVE KEPT POPS FOR AFTERNOON PRETTY MUCH AS PREVIOUS
FORECAST HAD IT...AND WILL TRY TO ADJUST TOWARD MIDDAY AS TRENDS GET
MORE CLEAR. TEMPS COULD ALSO NEED TWEAKED AT THAT TIME...BUT CURRENT
TREND OF GOING BLO GUIDANCE SEEMS REASONABLE GIVEN OUTFLOW AND DEBRIS
ACROSS AREA ATTM.
&&
.PREV DISCUSSION... /ISSUED 353 AM CDT THU JUL 18 2013/
..STRONG TO SEVERE STORMS POSSIBLE ACROSS THE ENTIRE REGION TODAY...
DISCUSSION...
SHORT TERM (TODAY THROUGH FRIDAY NIGHT)...THE UPPER TROPOSPHERIC
(TUTT) LOW WHICH HAS BEEN HELPING INSTIGATE CONVECTION TO OUR EAST
THE PAST FEW DAYS IS NOW IN A POSITION TO INCREASE OUR SHOWER AND
THUNDERSTORM CHANCES. IN FACT...JUXTAPOSED LIFT AND INSTABILITY
ASSOCIATED WITH THE LOW HAS BEEN GREAT ENOUGH TO ADVECT SHOWERS AND
THUNDERSTORMS INTO EAST-CENTRAL AND NORTHEASTERN PORTIONS OF
MISSISSIPPI OVERNIGHT. SOME OF THIS ACTIVITY HAS BEEN QUITE
VIGOROUS...PRODUCING GUSTY WINDS AT LEAST OVER 40 MPH OVER LARGE
PORTIONS OF THE GOLDEN TRIANGLE. HIGH RESOLUTION MODELS GENERALLY
SUGGEST ACTIVITY BUILDING DOWN THROUGH THE HEART OF THE REGION
THROUGH MIDDAY...AND THEN BECOMING CONCENTRATED IN WESTERN
(ESPECIALLY SOUTHWESTERN) ZONES BY THIS AFTERNOON. RELATIVELY COLD
TEMPERATURES ALOFT WILL CREATE RATHER STEEP LAPSE RATES (26 TO 28
VERT TOTALS) WITH ENOUGH DEEP LAYER SHEAR TO OCCASIONALLY ORGANIZE
GUSTY THUNDERSTORM LINE SEGMENTS. EARLY ONSET OF CONVECTION
(ESPECIALLY IN CENTRAL AND EASTERN ZONES) WILL IN MANY CASES KEEP
INSTABILITY FROM MAXIMIZING...BUT ALL THE INGREDIENTS FOR AT LEAST
ISOLATED SEVERE SUMMER STORMS STILL SEEM TO BE THERE. THIS RISK WILL
BE MENTIONED IN THE HWO (WITH THE FOCUS ON DAMAGING WIND GUSTS). GFS-
BASED MAV GUIDANCE REALLY STRUGGLING TO CATCH UP TO THE SITUATION
THIS MORNING AND ITS POPS WERE INCREASED RATHER
SIGNIFICANTLY...ALTHOUGH NOT BY A HUGE AMOUNT IN PORTIONS OF EAST-
CENTRAL MS WHERE MAIN CONVECTIVE BANDS MAY PASS THROUGH BEFORE THE
TODAY PERIOD STARTS. MAV TEMPS OF COURSE DEEMED AT LEAST 2 TO 4
DEGREES TOO HIGH IN MOST LOCALES DUE TO THE EXPECTED WETTER OUTCOME
TO THE DAY.
QUITE A FEW MODELS BLOW UP SO MUCH CONVECTION ACROSS OUR REGION
THROUGH EARLY TO MID AFTERNOON THAT IT IS CONCEIVABLE THERE MAY NOT
BE MUCH AROUND BY LATE AFTERNOON TO EARLY EVENING. THIS IS CONTRAST
TO USUAL PEAK CONVECTION TIME AROUND HERE IN THE SUMMER.
HOWEVER...VICINITY OF THE UPPER LOW CENTER TO OUR SOUTH WILL
INCREASE OUR CHANCES OF AT LEAST ISOLATED LATE NIGHT CONVECTION
FORMING ACROSS OUR REGION...ALTHOUGH INGREDIENTS FOR TRIGGERING DO
NOT APPEAR NEARLY AS ABUNDANT AS IS THE CASE RIGHT NOW. THE NEXT
SHIFT WILL HAVE TO MONITOR POTENTIAL FOR ANY POTENT LATE NIGHT
STORMS...BUT AS OF RIGHT NOW THE RISK OF ANY SEVERE ACTIVITY DOES
NOT LOOK VERY HIGH.
THE PICTURE FOR FRIDAY GETS A BIT MURKIER. SEEMS AS IF CONVECTION
TODAY IN THE MODELS DISRUPTS LOW LEVEL WIND FIELDS SO MUCH THAT THEY
HAVE A HARD TIME REORGANIZING AGAIN BY FRIDAY. THIS RESULTS IN A
LACK OF TRIGGERING MECHANISMS IN OUR REGION AND THUS A SURPRISING
LACK OF CONVECTION GIVEN STILL FAVORABLE UPPER LEVEL SCENARIO. THERE
IS A POSSIBILITY THESE DRY-LOOKING MODELS MAY BE ON TO SOMETHING BUT
I AM GUESSING THEY ARE TOO DRY AND HAVE BOOSTED POPS TO A 30 TO 40
PERCENT RANGE. THE NEXT SHIFT SHOULD LIKELY HAVE A BETTER HANDLE ON
THE SITUATION FOR TOMORROW. GIVEN UNCERTAINTIES I MAY DOWNPLAY
SEVERE POTENTIAL IN THE HWO A LITTLE...ALTHOUGH STILL MENTIONING
SOME RISK. FOLLOWED TREND OF ENSEMBLE GFS MOS AND CUT MEXMOS HIGHS
FOR FRIDAY BY ONE OR TWO DEGREES. /BB/
LONG TERM (SATURDAY THROUGH NEXT THURSDAY)...THE WEATHER PATTERN
WILL REMAIN SOMEWHAT ACTIVE DURING THE EXTENDED PART OF THE FORECAST
AS MULTIPLE UPPER DISTURBANCES SWING ACROSS THE REGION DURING THE
PERIOD.
ON SATURDAY A TUTT LOW WILL BE SITUATED OVER THE LOWER MS VALLEY.
WITH A RATHER MOIST AIRMASS IN PLACE ACROSS THE REGION...THIS FEATURE
WILL LIKELY AID IN THE DEVELOPMENT OF SCATTERED CONVECTION DURING THE
DAY. MOVING INTO SUNDAY AND MONDAY THE LOW WILL OPEN UP AND BECOME
ABSORBED BY THE LARGER-SCALE UPPER TROUGH BROADENING OVER THE EASTERN
CONUS. THIS WILL PUT THE ARKLAMISS IN WNW/NORTHWESTERLY FLOW ALOFT
THROUGH THE MIDDLE OF NEXT WEEK. A SERIES OF SHORTWAVE IMPULSES WILL
TRAVERSE THIS UPPER FLOW PATTERN BRINGING MULTIPLE OPPORTUNITIES FOR
RAIN FROM THE WEEKEND INTO THE FIRST HALF OF NEXT WEEK. CHANCE POPS
WERE MAINTAINED FOR SEVERAL PERIODS IN THE EXTENDED.
THE 00Z MODEL SUITE SUGGESTS THE UPPER TROUGH MAY NOT DEEPEN QUITE AS
MUCH OVER OUR REGION EARLY NEXT WEEK AS INDICATED IN PREVIOUS RUNS
DUE TO A STRENGTHENING UPPER RIDGE EXTENDING FROM THE SOUTHERN
PLAINS INTO THE NORTHERN GULF. THIS RIDGE WOULD BECOME THE BIGGER
PLAYER IN OUR FORECAST MID TO LATE NEXT WEEK...BRINGING AN END TO
THE STRETCH OF DAYS WITH ABOVE-CLIMO POPS. THIS WOULD ALSO CRANK UP
THE HEAT...WITH HIGH TEMPERATURES IN THE MID 90S BECOMING MORE
PREVALENT.
WITH REGARDS TO FORECAST SPECIFICS...POPS WERE GENERALLY A COMPROMISE
BETWEEN MAV GUIDANCE AND ENSEMBLE MEANS. UNDERCUT MAV/MEX HIGHS
THROUGH MUCH OF THE PERIOD DUE TO THE INCREASED PRESENCE OF CLOUDS
AND PRECIPITATION. /DL/
&&
.AVIATION...
SCATTERED SHOWERS AND THUNDERSTORMS WILL GRADUALLY
SPREAD WEST THROUGH THE AERODROME THROUGHOUT THE DAY...WITH ACTIVITY
AFFECTING GTR/CBM/NMM/MEI/PIB/HBG MAINLY THIS MORNING. MVFR TO
OCCASIONALLY IFR CONDITIONS AND GUSTY WINDS WILL BE FOUND IN THE
MIDST OF THE THUNDERSTORMS...BUT OUTSIDE OF MOST CELLS CONDITIONS
SHOULD BE MAINLY VFR. ACTIVITY SHOULD BE CONCENTRATED AROUND
GWO/JAN/HKS BY LATE MORNING TO MIDDAY...AND THEN AROUND HEZ/TVR/GLH
BY AFTERNOON. /BB/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 91 69 92 70 / 57 24 32 26
MERIDIAN 91 69 92 68 / 54 24 31 26
VICKSBURG 91 68 92 68 / 58 24 31 26
HATTIESBURG 91 70 92 70 / 94 24 40 26
NATCHEZ 91 69 92 69 / 64 24 39 26
GREENVILLE 95 71 93 72 / 41 24 30 26
GREENWOOD 92 70 93 70 / 35 24 30 26
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
AEG
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
1118 PM CDT WED JUL 17 2013
.UPDATE...LOOKING INCREASINGLY LIKELY THAT AT LEAST ISOLATED SHOWERS
AND STORMS WILL START TO MIGRATE WEST INTO THE REGION FROM ALABAMA
BEFORE DAYBREAK. NO SUGGESTION YET THAT ANY VERY ORGANIZED ACTIVITY
WILL COME INTO THE AREA BEFORE THIS TIME. FORECAST UPDATED AGAIN TO
INCREASE POPS A LITTLE MORE OVER THE PREVIOUS UPDATE. /BB/
&&
.PREV DISCUSSION... /ISSUED 855 PM CDT WED JUL 17 2013/
..STRONG TO SEVERE STORMS POSSIBLE TOMORROW AFTN/ERLY EVE...
UPDATE...SMALL DISTURBANCE PRECEDING LARGER DISTURBANCE
UNDERCUTTING RIDGE TO OUR NORTH HAS BEEN RESPONSIBLE FOR KICKING OFF
SCATTERED (AND OCCASIONALLY POTENT) THUNDERSTORMS THIS AFTERNOON
UNTIL JUST RECENTLY OVER SOUTHERN PORTIONS OF THE FORECAST AREA.
THIS SMALL DISTURBANCE IS MOVING OFF TO THE WEST AND GETTING READY
TO CLEAR THE REGION...ALTHOUGH A STRAY SHOWER OR STORM CANNOT BE
RULED OUT OVER THE NEXT FEW HOURS IN SOUTHWESTERN ZONES.
LATER TONIGHT THE WESTERN FRINGES OF THE LARGER DISTURBANCE (TUTT
TYPE LOW) WILL BE MOVING IN FROM THE EAST. PREVIOUS DISCUSSION
TALKED OF HOW MODELS HAD BEEN DOWNPLAYING ANY REDEVELOPMENT OF
CONVECTION IN OUR REGION LATE TONIGHT IN ASSOCIATION WITH THE
APPROACHING LOW ALOFT. HOWEVER...LATEST HRRR RUNS SHOW AT LEAST SOME
ISOLATED CONVECTION IN EASTERN MS LATE TONIGHT...AND THIS SEEMS
FEASIBLE GIVEN MODEL INSTABILITY OUTPUT AND THE FACT THAT SHOWERS
AND STORMS ARE NOW INCREASING IN EASTERN ALABAMA (AND MIGRATING
SLOWLY THIS DIRECTION). THUS...FORECAST FOR LATE TONIGHT THROUGH THE
MORNING HOURS TOMORROW UPDATED TO INCLUDE MENTION OF ISOLATED
SHOWERS/STORMS GRADUALLY SPREADING WEST. GIVEN STABILIZING BOUNDARY
LAYER LATE TONIGHT ANY ELEVATED INSTABILITY DRIVING STORM
DEVELOPMENT (IF SUCH OCCURS) SHOULD IMPART MINIMAL POTENTIAL FOR
HAZARDOUS WEATHER...ALTHOUGH LOCALIZED HEAVY DOWNPOURS ARE CERTAINLY
POSSIBLE. /BB/
PREV DISCUSSION... /ISSUED 412 PM CDT WED JUL 17 2013/
DISCUSSION...SHOWERS AND A FEW THUNDERSTORMS ARE ONGOING ACROSS
SOUTH MS AND PORTIONS OF NE LA AS AFTERNOON CONVECTIVE TEMPERATURES
ARE BEING REACHED IN THE LOW TO MID 90S. SHOWER/STORM COVERAGE IS
NOT GREAT ACROSS THE REGION, AS EXPECTED, WITH SYNOPTIC SUBSIDENCE
PREVAILING AS A RESULT OF H5 RIDGE INFLUENCE CENTERED OVER THE OHIO
VALLEY. ANOTHER NOTABLE FEATURE IS A DEVELOPING TUTT LOW AND
ASSOCIATED S/WV VORTICITY IMPULSES TRAPPED IN THE EASTERLY MID-LVL
FLOW ON THE SOUTHERN PERIPHERY OF THE LARGE H5 RIDGE ACROSS THE WRN
GOM AND SOUTHERN ATLANTIC SEABOARD. THIS TUTT WILL AID IN THE STORMS
TOMORROW.
CURRENT SHOWER AND THUNDERSTORM ACTIVITY WILL SLOWLY DIMINISH
THROUGH THE EARLY EVENING HOURS AS THE ATMOSPHERE DESTABILIZES BUT AN
OUTSIDE STRONG STORM MAY BE POSSIBLE IF MERGERS OCCUR. THE POTENTIAL
FOR STRONG STORMS ACROSS FAR EAST MS TONIGHT HAS BEEN DECREASING WITH
ACTIVITY REMAINING CONFINED IN GA THIS AFTN AND STRUGGLING FARTHER
WEST IN AL WITH A DIMINISHING CU FIELD. LOCAL WRF AND HRRR SUPPORT
THIS THINKING AND HAVE ADJUSTED POPS/WX FOR THE OVRNGT PERIOD
ACCORDINGLY.
AS TUTT LOW INFLUENCE INCREASES TOMORROW, A NOTABLE LOW-LVL
CONVERGENT WIND FIELD LOOKS TO DEVELOP, CREATING AN INITIAL
CONVECTIVE TRIGGERING MECHANISM. A MORE THAN SUPPORTIVE THERMO
ENVIRONMENT LOOKS TO BE IN PLACE WITH >3000 J/KG SBCAPE, 27-28C
VERTICAL TOTALS AND STEEP LOW-LVL LAPSE RATES WITH TOMORROW LIKELY
THE WARMEST OF THE WEEK AS READINGS CLIMB INTO THE MID 90S. IT`S
TOUGH TO PINPOINT WHAT AREA WILL BE MORE FAVORED FOR SCATTERED TO
NUMEROUS STORM DEVELOPMENT AS IT WILL DEPEND ON H5 INVERTED TROUGH
AXIS LOCATION AND SPEED. NAM AND SUBSEQUENT HI-RES OUTPUT BASED ON
ITS INITIAL CONDITIONS ARE A BIT FASTER THAN GFS AND DEPICT BEST
COVERAGE IN CENTRAL AND WEST AREAS WITH GFS A TOUCH SLOWER WITH
POTENTIAL GREATER COVERAGE IN THE EAST. HAVE BLENDED THE TWO (WHICH
IS MUCH HIGHER THAN MAV POPS SUGGEST AND FOLLOWED MUCH CLOSER TO MET
GUIDANCE FOR THURS AFTN PERIOD. GIVEN HIGH LAPSE RATES AND ADEQUATE
INSTABILITY, STRAIGHT LINE WINDS OF 60 MPH, HAIL, AND HEAVY
DOWNPOURS WILL BE LIKELY INVOF STRONGEST STORMS. STORM MOTION WILL
BE SLOW AS ATM COLUMN HAS LITTLE FLOW, FURTHER AIDING IN LOCALIZED
POTENTIAL FOR FLASH FLOODING. ACTIVITY WILL SLOWLY DIMINISH THROUGH
THE MID TO LATE LATE EVE AS THE MID-UPPER LOW TRAVERSES WEST ACROSS
THE SABINE RIVER.
FOR FRIDAY...ANOTHER ROUND OF DECENT COVERAGE OF SHOWERS AND STORMS
AS CONTINUED FAVORABLE LIFT AND INSTABILITY REMAIN IN THE AREA WITH
THE TUTT LOW OVER ERN TX. SOME STORMS DURING FRI AFTN COULD AT LEAST
BE ON THE STRONG SIDE AND WILL HAVE TO MONITOR MESOSCALE EVOLUTION
THURSDAY TO SEE IF SEVERE STORMS COULD BE ATTAINED FRIDAY. HAVE
ADDED WORDING TO THE HWO/GRAPHICS FOR FRIDAY AFTN FOR THIS STRONG
STORM POTENTIAL.
FOR FORECAST ELEMENTS...MET POPS WERE USED AS A STARTING POINT FOR
TOMORROW IN LIEU OF LOW MAV POPS. POPS WERE ALSO BOOSTED FRIDAY WITH
WEAKNESS IN THE RIDGE AND TUTT LOW INFLUENCE. MAV LOW TEMPS WERE
BUMPED UP 1-3F DEGREES WITH HIGHS BUMPED DOWN 2F DEGREES BASED ON
RECENT TRENDS. /ALLEN/
&&
.AVIATION...
MAINLY VFR CONDITIONS ARE ANTICIPATED THROUGH TONIGHT
AND INTO THE MORNING HOURS. HOWEVER...THERE WILL BE THE POTENTIAL
FOR ISOLATED SHOWERS/STORMS LATE TONIGHT IN EASTERN MS AND IN ALL
AREAS TOMORROW MORNING. CHANCES FOR ANY OF THIS ACTIVITY HITTING TAF
SITES RATHER LOW...BUT IF IT OCCURS THEN BRIEF IFR CONDITIONS IN
THIS TIME PERIOD NOT IMPOSSIBLE. OTHERWISE...A MUCH GREATER COVERAGE
OF CONVECTION AREAWIDE TOMORROW AFTERNOON INTO TOMORROW EVENING
ALTHOUGH AWAY FROM STORMS IN THIS PERIOD MOST FLIGHT CATS SHOULD
STILL REMAIN VFR. /BB/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 72 93 72 93 / 15 39 21 39
MERIDIAN 69 93 72 93 / 21 30 21 38
VICKSBURG 69 93 72 93 / 12 46 22 38
HATTIESBURG 72 93 73 93 / 22 42 21 44
NATCHEZ 70 91 72 91 / 14 46 21 48
GREENVILLE 74 95 74 94 / 11 46 20 37
GREENWOOD 72 94 72 94 / 14 30 17 40
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
BB/ALLEN
AREA FORECAST DISCUSSION
NWS GLASGOW MT
247 PM MDT THU JUL 18 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SATURDAY...
A VERY WELL MIXED BOUNDARY LAYER THIS AFTERNOON AND EVENING HAS
BEEN LEADING TO GUSTY NORTHWEST WINDS ACROSS THE CWA. NOTICED THAT
SOME GUSTS HAVE BEEN APPROACHING 40 MPH AT TIMES. THEREFORE THE
GOING LAKE WIND ADVISORY LOOKS GOOD. WINDS ARE EXPECTED TO SUBSIDE
THIS EVENING...ESPECIALLY AROUND OR AFTER SUNSET. AT THAT TIME THE
NEXT SHIFT CAN HAVE A LOOK AT DETERMINING WHETHER OR NOT THE
HEADLINES CAN BE DROPPED A LITTLE EARLY. FOR NOW...WILL LEAVE IT
TO EXPIRE AT MIDNIGHT. DEEP VERTICAL MIXING HAS ALSO LED TO
TEMPERATURES SOARING INTO THE MIDDLE AND UPPER 80S ACROSS THE
FORECAST AREA WITH A FEW LOCATIONS TOPPING 90. SOME LOCATIONS WERE
EVEN A TAD WARMER THAN EXPECTED. CUMULUS FIELD EVIDENT ON THE
VISIBLE SATELLITE IMAGERY PUSHING INTO THE NORTHERN ZONES FROM
SOUTHERN SASKATCHEWAN. DO EXPECT THAT WHILE THE UPPER SHORT WAVE
MAY CLIP THE NORTHEASTERN ZONES THAT MUCH OF THE UPPER LEVEL
ENERGY WILL REMAIN NORTH AND EAST OF THE CWA. FELT THAT IT WAS
OKAY TO LEAVE IN SLIGHT CHANCE POPS FOR THE AFTERNOON AND EVENING
HOWEVER. LATEST HRRR MODEL DOES INDICATE POTENTIAL FOR AN ISOLATED
SHOWER OR THUNDERSTORM ACROSS PERHAPS DANIELS OR SHERIDAN COUNTY
RIGHT AROUND OR JUST AFTER 00Z.
FRIDAY AND SATURDAY...18/12Z MODEL GUIDANCE CONTINUES TO LEAVE
NORTHEAST MONTANA UNDER A REGIME OF NORTHWEST FLOW ALOFT.
SHORTWAVE ENERGY PROPAGATING THROUGH THE FLOW WILL BRING ABOUT
PERIODIC OPPORTUNITIES FOR SHOWERS AND THUNDERSTORMS... AS IT
RIDES OVER THE TOP OF A BACKDOOR COLD FRONT THAT IS EXPECTED TO
STALL OUT ACROSS THE CWA. MOISTURE IS EXPECTED TO BE QUITE
LIMITED. THEREFORE KEPT SLIGHT CHANCE TO LOW END CHANCE POPS GOING
FOR NOW...ESPECIALLY IN THE NORTHERN AND EASTERN PORTIONS OF THE
CWA. TEMPERATURES LOOK TO BE FAIRLY SEASONABLE WITH 850MB
TEMPERATURES EXHIBITING A SHARP GRADIENT WITH WARMER TEMPERATURES
ACROSS THE SOUTHWEST AND COOLER IN THE NORTHEAST. WITH THE
FORECAST REGION REMAINING ON THE NORTHEAST PERIPHERY OF THE UPPER
RIDGE ACROSS THE SOUTHWESTERN U.S. HOWEVER...DO NOT EXPECT ANY
MAJOR TRENDS IN TEMPERATURES THROUGH EARLY IN THE WEEKEND. MINOR
FLUCTUATIONS DAY TO DAY ARE POSSIBLE...BUT PERSISTENCE MAY BE A
NICE BASELINE TO START FROM FOR THE FORECAST FOR AT LEAST THE NEXT
COUPLE OF DAYS. WITH ANTICIPATED 850MB TEMPERATURE PATTERN...FULL
MIXING WOULD PROBABLY ENABLE HIGHS AROUND 90 IN PETROLEUM
COUNTY...RANGING TO CLOSER TO 90 IN SHERIDAN COUNTY FURTHER
NORTHEAST. LOW TEMPERATURES EACH MORNING MAY RANGE IN THE UPPER
50S TO LOW 60S. MALIAWCO
.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY...
MAIN CHANGE WAS ADD MENTION OF THUNDERSTORMS FOR LATE MONDAY. ECMWF
REMAINS CONSISTENT WITH A DECENT VORT MAX MOVING EAST INTO MONTANA
AND DECENT INSTABILITY IN PLACE. CURRENT HWO DOES NOT MENTION
SEVERE THUNDERSTORM POSSIBILITY BUT LATER SHIFTS MAY HAVE TO ADD
THIS MENTION IF MODELS START TO LEAN IN THIS DIRECTION. REST OF
FORECAST MAINLY UNCHANGED. TFJ
PREVIOUS DISCUSSION...
BOTH THE ECMWF AND THE GFS MAINTAIN A WNW FLOW ALOFT IN TONIGHT/S
00Z MODEL RUNS THROUGH THE PERIOD. HOWEVER...THERE HAS BEEN RUN TO
RUN DIFFERENCES AND DIFFERENCES IN TIMING SHORTWAVES WITHIN THE
FLOW ALOFT. GENERALLY...MONTANA WILL BE ON PERIPHERY OF WESTERN
U.S. UPPER RIDGE.
AT THIS POINT...BOTH GFS AND ECMWF POINT TOWARDS SUNDAY AND MONDAY
BEING WARM AND MAINLY DRY WITH A SHORTWAVE RIDGE. MONDAY NIGHT AND
TUESDAY...ECMWF IS STRONGER AND SOMEWHAT FASTER WITH A COLD FRONT.
EITHER WAY...IT LOOKS LIKE LIMITED MOISTURE SO WILL MAINTAIN DRY
FORECAST FOR NOW AND KEEP TEMPERATURES CLOSE TO INHERITED FORECAST.
WEDNESDAY AND THURSDAY...WNW FLOW ALOFT CONTINUES WITH MODELS
TIMING SYSTEMS DIFFERENTLY. THEY GENERALLY KEEP THE AREA DRY WITH
TEMPERATURES AT OR SLIGHTLY ABOVE NORMAL. FORRESTER
&&
.AVIATION...
VFR. NORTHWEST WINDS WILL SIGNIFICANTLY DIMINISH THIS EVENING
ABOUT 03Z TO LIGHT SPEEDS. NW WINDS WILL PICK UP AGAIN FRIDAY
AFTERNOON BUT NOT NEARLY AS STRONG AS TODAY. A BACKDOOR COLD FRONT
WILL KEEP MOST VFR CLOUDS TO THE NORTH AND EAST OF THE TERMINALS
LATER FRIDAY. TFJ
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY UNTIL MIDNIGHT MDT TONIGHT FOR FORT PECK LAKE
FOR CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN
VALLEY...GARFIELD...MCCONE...PETROLEUM.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1149 PM MDT WED JUL 17 2013
.AVIATION...
06Z TAF CYCLE
AN UPPER LEVEL LOW PRESSURE SYSTEM WILL TRACK SLOWLY SWWD FROM SW
NM TONIGHT INTO NW MEXICO BY THURSDAY EVENING. THIS TRACK AND
PERSISTENT...MOIST...SE LOW LEVEL FLOW ON THE BACK SIDE OF THE LOW
SHOULD FAVOR THE S CENTRAL MTS AND SE PLAINS FOR PERIODS OF LIGHT
RAIN AND POSSIBLY A FEW THUNDERSTORMS TONIGHT...THEN THE
MOUNTAINS AND AREAS S OF HIGHWAY 60 ON THURSDAY. THE UPSLOPE FLOW
ON THE PLAINS IS EXPECTED TO PRODUCE WDSPR MVFR AND IFR CONDITIONS
IN LOW CLOUDS AND A LITTLE PATCHY FOG ACROSS THE E TONIGHT INTO
THURSDAY MORNING...WITH A RISK OF AIRPORTS ALONG THE E SLOPES OF
THE CENTRAL MT CHAIN...INCLUDING KLVS AND KROW...DROPPING BELOW
AIRPORT MINIMUMS. FLIGHT CATEGORY RESTRICTIONS MAY LINGER INTO THE
EARLY AFTN THURSDAY ALONG AND E OF THE S CENTRAL MTS. LOW CLOUDS
SHOULD BE PATCHIER THURSDAY NIGHT...WHEN THEY SHOULD FAVOR
LOCATIONS E OF THE S CENTRAL MTS.
44
&&
.PREV DISCUSSION...625 PM MDT WED JUL 17 2013...
DECIDED TO KEEP FFA IN EFFECT FOR ROOSEVELT COUNTY THROUGH TONIGHT
AS RADAR TRENDS SHOW SIGNIFICANT AREA OF LOCALLY HEAVY RAINFALL RE-
DEVELOPING OVER WEST TEXAS LAST COUPLE HOURS. THE 21Z HRRR AND 23Z
RUC SOLUTION ARE IN AGREEMENT ALL CONVECTIVE ACTIVITY WILL BECOME
A MORE WIDESPREAD AREA OF MODERATE TO PERHAPS LOCALLY HEAVY RAIN
OVERNIGHT ALONG AND NEAR THE HIGH TERRAIN OF SOUTH CENTRAL AND
SOUTHEAST NM. FARTHER NORTH AND WEST HAVE LOWERED POPS ACCORDINGLY
AS GUIDANCE AND LATEST SATELLITE TRENDS SHOW LOTS OF CLEARING. SOME
REDEVELOPMENT MAY OCCUR DURING THE PREDAWN HOURS AS IS OFTEN THE
CASE IN MOIST MONSOON FLOW HOWEVER COVERAGE WILL BE VERY LIMITED.
GUYER
.PREV DISCUSSION...257 PM MDT WED JUL 17 2013...
THE LATEST WATER VAPOR SATELLITE IMAGERY SHOWS THE UPPER LOW
PROGRESSING SOUTHWEST ACROSS THE RIO GRANDE NEAR T-OR-C...WITH DRY
AIR WRAPPING INTO THE WEST SIDE OF THE CIRCULATION AND A VERY
MOIST ATMOSPHERE ON THE EAST SIDE. AREA 12Z UPPER AIR SOUNDINGS
CONFIRMED THIS...WITH BOTH KAMA AND KMAF SHOWING PWATS AROUND 1.5
INCHES AND ONLY 0.92 HERE AT KABQ (STILL SLIGHTLY ABOVE NORMAL).
12Z MODEL TIME SERIES FOR KABQ SHOWS PWAT INCREASING TO BETWEEN
1.1 AND 1.3 INCHES OVERNIGHT AND STAYING THERE THROUGH THE
WEEKEND. THIS INCREASE IN MOISTURE COMBINED WITH INCREASING TEMPS
EACH DAY SHOULD BRING BETTER CHANCES FOR RAIN TO THE ABQ METRO
FROM FRIDAY INTO THE WEEKEND.
FURTHER SOUTH...A FLASH FLOOD WATCH REMAINS IN EFFECT FOR MUCH OF
SOUTHEAST AND SOUTH CENTRAL PORTIONS OF THE STATE. WE`RE EXTENDING
OUR FLASH FLOOD WATCH FOR LINCOLN AND CHAVES COUNTY THROUGH
THURSDAY MORNING...BUT DROPPING ROOSEVELT AS THE FOCUS SHIFTS TO
THE FAVORED UPSLOPE AREAS OF THE SOUTH CENTRAL MOUNTAINS...
INCLUDING THE LITTLE BEAR BURN SCAR AND SOUTHWEST CHAVES COUNTY.
THE THREAT ON THURSDAY MAY PERSIST OVER THE SOUTH CENTRAL
MOUNTAINS AND WILL DEFINITELY PICK-UP OVER CATRON COUNTY AND THE
WHITEWATER-BALDY BURN SCAR. HIGH POP...HIGH PWAT SCENARIO WITH
UPSLOPE TO BOOT...BUT NOT THE BEST SURFACE BASED INSTABILITY
GIVEN EXTENSIVE CLOUD COVER FORECAST THURSDAY. STORM MOTION WILL
DECREASE SIGNIFICANTLY ON THURSDAY ACROSS NORTHERN PORTIONS OF THE
FORECAST AREA AS THE LOW PULLS FURTHER AWAY...SO ANY STORMS THAT
FORM OVER THE NORTH WILL BE MOVING SLOWER. HOWEVER...THE WARM-UP
ON THURSDAY WILL NOT BE SIGNIFICANT ENOUGH TO PRODUCE DEEPER
CONVECTION. THIS ALL CHANGES BY FRIDAY AS THE UPPER LOW WILL BE
OVER NORTHERN MEXICO AND STORM MOTION WILL BE EVEN LIGHTER ACROSS
THE NORTHERN MOUNTAINS. MORE WARMING ON FRIDAY WILL INCREASE
SURFACE BASED INSTABILITY WHILE PWATS REMAIN ABOVE TO WELL ABOVE
NORMAL. THIS ADDS-UP TO A LOCALLY HEAVY RAINFALL THREAT FRIDAY...
WITH PARTICULAR CONCERN FOR NORTHERN BURN SCARS. LOOK FOR A REPEAT
ON SATURDAY...WITH STORM MOTION NEAR ZERO FOR THE NORTHERN
MOUNTAINS.
LOOK FOR A CONVECTIVE DOWNTREND EARLY NEXT WEEK AS THE UPPER HIGH
OVER NEVADA MOVES EAST OR SOUTHEAST TO OVER CO/NM BY WEDNESDAY.
THE CONVECTIVE DOWNTREND DUE TO DECREASING MOISTURE AND INCREASING
PRESSURE HEIGHTS UNDER THE INFLUENCE OF A 595DAM 500MB HIGH.
TEMPERATURES ARE FORECAST TO BE BACK ABOVE NORMAL AREA-WIDE BY
TUESDAY AND STAY THERE FOR AWHILE.
11
.FIRE WEATHER...
LATEST IR IMAGERY INDICATES THAT THE UPPER LOW IS POSITIONED NEAR
SOCORRO...AND WILL CONTINUE TO SLIDE TOWARDS FAR SOUTHWEST NEW
MEXICO THIS EVENING. SHOWERS WILL CONTINUE ACROSS SOUTHEAST PORTIONS
OF THE STATE THROUGH THE REST OF THE DAY...AND BECOME MORE
CONVECTIVE WITH DAYTIME HEATING. THE FOCUS FOR THE HEAVIEST RAINS
WILL BE OVER THE SACRAMENTO MOUNTAINS AND COULD IMPACT BURN SCARS IN
THAT AREA. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL
ALSO BE POSSIBLE PRIMARILY OVER THE NORTHERN AND SOUTHWEST
MOUNTAINS. EAST WINDS AT 20 TO 30 MPH WITH GUSTS TO 40 MPH WILL
RETURN LATE THIS EVENING FOR THE ABQ METRO DUE TO A STRENGTHENED
PRESSURE GRADIENT. LITTLE CHANGE IN OVERNIGHT RH RECOVERIES IS
EXPECTED AND ANOTHER ROUND OF LOW CLOUDS AND PATCHY FOG WILL BE
POSSIBLE ACROSS THE EASTERN PLAINS.
THE UPPER LOW WILL CONTINUE TO WEAKEN AS IT MOVES OVER NORTHWEST
MEXICO THURSDAY. THE MAIN MOISTURE PLUME WILL BE FOCUSED OVER THE
SOUTHWEST MOUNTAINS...THOUGH SHOWER AND THUNDERSTORM ACTIVITY WILL
REMAIN POSSIBLE ACROSS MUCH OF THE STATE WITH DIURNAL HEATING.
TEMPERATURES WILL REMAIN BELOW NORMAL FOR MOST OF THE STATE...THOUGH
A 5 TO 10 DEGREE WARM-UP FROM WEDNESDAYS HIGHS IS EXPECTED.
LITTLE CHANGE IN OVERALL PATTERN FRIDAY AND INTO THE WEEKEND AS THE
UPPER LOW CONTINUES ITS SLOW TREK WEST WITH HIGH PRESSURE TO THE
NORTH SLOWLY BUILDING BACK OVER THE STATE. DIURNAL CONVECTION EACH
DAY WILL BE FOCUSED OVER WESTERN AND CENTRAL NEW MEXICO AND FAVOR
THE HIGH TERRAIN. A SLIGHT DRYING TREND THROUGH THIS PERIOD IS
EXPECTED...THOUGH OVERNIGHT RH RECOVERIES WILL REMAIN GOOD ALL AREAS
EXCEPT VALLEY LOCATIONS WHERE RECOVERIES WILL BECOME FAIR.
TEMPERATURES WILL TREND UP...REACHING NEAR NORMAL VALUES FOR THE
NORTHERN AND CENTRAL NEW MEXICO BY MONDAY. POCKETS OF FAIR TO POOR
VENTILATION RATES WILL BE POSSIBLE EACH DAY...MAINLY ACROSS
NORTHWEST NEW MEXICO.
THE GFS AND ECMWF SHOW SOMEWHAT SIMILAR DEPICTIONS FOR EARLY NEXT
WEEK. HIGH PRESSURE WILL BUILD OVER THE GREAT BASIN AND STRETCH OVER
THE STATE...RESULTING SHOWER AND THUNDERSTORM ACTIVITY ALONG THE
NM/AZ BORDER. THE PROGRESSION OF THIS HIGH PRESSURE EAST THROUGH THE
WEEK IS DEPICTED DIFFERENTLY...BUT A DECREASE IN SHOWER AND
THUNDERSTORM COVERAGE WILL BE POSSIBLE.
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 6 AM MDT THURSDAY FOR THE FOLLOWING ZONES...
NMZ526-536-538>540.
&&
$$
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
339 PM EDT THU JUL 18 2013
.SYNOPSIS...
AN ACTIVE WEATHER PATTERN WILL CONTINUE ACROSS THE NORTH COUNTRY
WITH DAILY CHANCES FOR SCATTERED SHOWERS AND THUNDERSTORMS...
ALONG WITH HOT AND HUMID CONDITIONS THROUGH THE END OF THE WEEK.
SOME STORMS COULD BE STRONG TO SEVERE THROUGH THE PERIOD. A COLD
FRONT WILL MOVE THROUGH ON SATURDAY BRINGING MUCH DRIER AND
COOLER AIR FOR SUNDAY AND MONDAY.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
AS OF 107 PM EDT THURSDAY...VISIBLE SATELLITE SHOWS DEVELOPING
CUMULUS/TOWERING CUMULUS CLOUDS ACROSS THE HIGHER TERRAIN...WITH
SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING ACROSS EASTERN
ONTARIO AND IN CENTRAL AND SOUTHERN NEW YORK. AIRMASS ALREADY
QUITE UNSTABLE WITH SBCAPES OF 2500-3500 J/KG PER LATEST RAP AND
LAPS ANALYSIS. BASED ON SATELLITE TRENDS AND THE LACK OF
CONVECTIVE INHIBITION...EXPECT AN INCREASE IN COVERAGE OF SHOWERS
AND THUNDERSTORMS ACROSS NORTHERN NEW YORK THROUGH THE NEXT COUPLE
OF HOURS WITH THIS ACTIVITY DEVELOPING/SPREADING INTO VERMONT BY
LATE AFTERNOON/EVENING. NO CHANGES TO POPS/WEATHER AS THESE ARE
REFLECTED IN THE CURRENT FORECAST...AND STILL BELIEVE ENHANCED
WORDING FOR GUSTY WINDS AND HEAVY RAINFALL IS JUSTIFIED GIVEN
DEGREE OF INSTABILITY AND FAVORABLE DEEP- LAYER SHEAR PROFILES.
PLEASE SEE OUR RECENTLY ISSUED SPECIAL WEATHER STATEMENT TO RAISE
AWARENESS OF POTENTIALLY STRONG THUNDERSTORMS THIS AFTERNOON AND
EVENING.
ENDED UP RAISING TEMPERATURES UP A DEGREE BASED ON CURRENT TRENDS.
STILL EXPECT HIGHS TODAY IN THE UPPER 80S TO LOWER 90S WITH HEAT
INDICES IN THE MID/UPPER 90S.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH SATURDAY NIGHT/...
AS OF 533 AM EDT THURSDAY...LINGERING CONVECTION THIS EVENING
WITH BR/FG DEVELOPING OVERNIGHT...ESP AT LOCATIONS THAT RECEIVE
RAINFALL. TOWARDS EARLY MORNING HOURS ON FRIDAY...NAM AND GFS
SHOW WARM FRONT LIFTING NWD...BEGINNING THREAT FOR SHOWERS AND
TSTMS EARLY. LLJ AROUND 30-45KTS WILL ACCOMPANY THE
FRONT...PROVIDING PLENTY OF SHEAR TO HELP ORGANIZE CONVECTION.
CAPE VALUES WILL BE EVEN HIGHER WITH OVER 2500 J/KG PSBL AND
SHOWALTER INDEX AROUND -3. CLEARLY DEFINE THETA E RIDGING
SUPPORTS INDICATIONS OF LARGE INSTABILITY OVER THE AREA. WARM
HUMID CONDITIONS CONTINUE ON FRIDAY...BUT FRONT WILL ALSO HAVE
SUPPORT FROM VORTICITY WHICH WILL CONTINUE TO MOVE OVER THE
REGION INTO THE OVERNIGHT. THEREFORE EXPECT BEST CHCS FOR
CONVECTION TO OCCUR ON FRIDAY INTO FRIDAY NIGHT AS MID LEVEL HT
FALLS SEE A MORE DRAMATIC CHANGE FRIDAY NIGHT WHILE UPPER LEVEL
TROUGH GAINS MOMENTUM EWD...GRAZING THE CENTRAL GREAT LAKES AND
PUSHING THE LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT AT THE
SFC FORWARD. GOING INTO SATURDAY...COLD FRONT WILL BE FOCUS OF
SHOWERS AND TSTMS...WITH CAPE OVER 1000 J/KG AND LI AROUND -3C.
UPPER LEVEL JET ACCOMPANYING THE FRONT WILL POSITION THE RR QUAD
OVER THE SLV FRIDAY NIGHT AND MOVE EWD THROUGHOUT THE DAY
SATURDAY. THE COLD FRONT DOESN/T LOOK TO EXIT ERN VT UNTIL LATE
SATURDAY INTO SATURDAY EVENING.
TEMPS WILL BE HOT WITH 925MB REACHING MID20S ON FRIDAY...
RESULTING IN SFC MAX TEMPS IN THE U80S-M90S...ESP IN SW DOWNSLOPE
AREAS LIKE PBG. HEAT INDEX VALUES WILL ONCE AGAIN APPROACH 100
DEGREES IN A FEW LOCATIONS MAINLY IN THE CPV AND CT VALLEY. WITH
MORE CLD COVER ON SATURDAY...EXPECT MAX TEMPS TO BE IN THE
M-U80S. OVERNIGHT MIN TEMPS WILL BE WARM...IN THE 60S- L70S.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 330 PM EDT THURSDAY...LARGE SCALE PATTERN CHANGE WL BRING
MUCH COOLER AND DRIER AIR INTO THE NORTH COUNTRY FOR SUNDAY INTO
MONDAY...BEFORE MORE UNCERTAINTY ASSOCIATED WITH NEXT SYSTEM
DEVELOPS BY TUES/WEDS OF NEXT WK. OVERALLL...GFS/ECMWF AND
ENSEMBLE DATA SHOW DEVELOPING TROF ACRS THE NE CONUS WITH SFC HIGH
PRES OVERHEAD ON SUN/MON...RESULTING IN DRY CONDITIONS WITH NEAR
NORMAL TEMPS. THE COMBINATION OF NW FLW...CAA...AND 85H TEMPS BTWN
6-8C WL RESULT IN HIGHS ONLY IN THE 60S MTNS TO 70S VALLEYS ON
SUN/MONDAY. BY TUES/WEDS...FAST WESTERLY FLW ALOFT DEVELOPS WITH
EMBEDDED VORTS AND AREAS OF ENHANCED MID LVL MOISTURE. SOME
UNCERTAINTY WITH REGARDS TO TROF AMPLIFICATION AND POTENTIAL
IMPACTS ACRS OUR CWA. WL MENTION CHC POPS ATTM WITH MORE WEIGHT
TWD THE ECMWF. OTHERWISE...PROGGED 85H TEMPS WARM BTWN
10-12C...SUPPORTING HIGHS BACK INTO THE 70S MTNS TO L/M80S VALLEY
BY THE MID OF NEXT WEEK. LOOK FOR OVERNIGHT LOWS MAINLY IN THE 50S
TO 60S WITH COMFORTABLE RH LVLS.
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
THROUGH 18Z FRIDAY...VFR CONDITIONS WL PREVAIL THIS
AFTN/EVENING...EXCEPT BRIEF PERIODS OF MVFR IN AND AROUND
THUNDERSTORMS. ALSO...ANTICIPATED LIGHTNING AND LOCALIZED GUSTY
WINDS IN THE STRONGER STORMS BTWN 18Z-00Z TODAY. CRNT RADAR TRENDS
SHOW STORMS IMPACTING MSS BY 19Z...WITH OTHER STORMS DEVELOPING
ACRS THE EASTERN DACKS WITH POTENTIAL IMPACTS TO PBG/BTV AND MPV
BTWN 19Z-22Z. HAVE USED TEMPO GROUP TO SHOW 3SM TSRA WITH CIGS BKN
AT 2500 TO 3000 KFT. TONIGHT...AVIATION CHALLENGE WL BE FOG/BR
POTENTIAL...AS LLVL WINDS INCREASE. THINKING MPV/SLK WL HAVE THE
BEST POTENTIAL FOR IFR CONDITIONS AS LLVLS DECOUPLE WITH MVFR
POSSIBLE AT RUT/MSS/BTV...ESPECIALLY IF RAIN OCCURS AT THESE SITES
THIS AFTN.
SOUTH TO SOUTHWEST WINDS WL INCREASE AT 10 TO 15 KNOTS WITH GUSTS
TO 20 TO 25 KNOTS BY FRIDAY MID MORNING.
OUTLOOK 18Z FRIDAY THROUGH MONDAY...SCATTERED AFTN/EVENING
SHOWERS/STORMS AGAIN ON FRIDAY/SATURDAY COULD PRODUCE BRIEF
PERIODS OF MVFR/IFR CONDITIONS. IN ADDITION...GUSTY SOUTHWEST
WINDS AHEAD OF AN APPROACHING COLD FRNT WL CONT ON FRIDAY
AFTN/NIGHT...BEFORE SHIFTING TO THE NORTHWEST ON SAT AFTN.
SUNDAY AND MONDAY...VFR UNDER BUILDING HIGH PRESSURE...EXCEPT
FOG/BR WITH MVFR/IFR AT MPV/SLK EACH MORNING BTWN 06-11Z.
&&
.CLIMATE...
HEAT WAVE HAS BEEN REACHED WITH PAST 3 DAYS MEETING OR EXCEEDING
90F AT KBTV. EXPECT HEAT WAVE TO CONTINUE WITH MAX TEMP OF 90
TODAY AND 94 ON FRIDAY...BEFORE A COLD FRONT APPROACHES ON
SATURDAY.
MAX TEMP RECORDS TODAY THROUGH FRIDAY. BEST SHOT OF REACHING OR
BREAKING RECORD MAX TEMPS ON FRIDAY AT KMPV AND KMSS. SHORTER
PERIOD OF RECORD AT THESE SITES THAN AT K1V4 AND KBTV.
07/18/2013 07/19/2013
KBTV 99/1953 98/1942
KMPV 96/1953 92/1991
K1V4 99/1953 95/1991
KMSS 95/1953 93/1991
&&
.EQUIPMENT...
KTYX IS BACK TO NORMAL OPERATIONS. SLK ASOS IS DOWN DUE TO COMMS
ISSUES...ETS ARE HEADING TO THE SITE AND SHOULD BE FIXED BY MID
AFTERNOON. ALSO...RUTLAND AWOS WILL BE UNAVAIABLE FROM 18 TO 20
UTC TODAY.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...KGM/TABER
NEAR TERM...KGM/LOCONTO
SHORT TERM...KGM
LONG TERM...TABER
AVIATION...TABER
CLIMATE...
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
140 PM EDT THU JUL 18 2013
.SYNOPSIS...
AN ACTIVE WEATHER PATTERN WILL CONTINUE ACROSS THE NORTH COUNTRY
WITH DAILY CHANCES FOR SCATTERED SHOWERS AND THUNDERSTORMS...
ALONG WITH HOT AND HUMID CONDITIONS THROUGH THE END OF THE WEEK.
SOME STORMS COULD BE STRONG TO SEVERE THROUGH THE PERIOD. A COLD
FRONT WILL MOVE THROUGH ON SATURDAY BRINGING MUCH DRIER AND
COOLER AIR FOR SUNDAY AND MONDAY.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
AS OF 107 PM EDT THURSDAY...VISIBLE SATELLITE SHOWS DEVELOPING
CUMULUS/TOWERING CUMULUS CLOUDS ACROSS THE HIGHER TERRAIN...WITH
SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING ACROSS EASTERN
ONTARIO AND IN CENTRAL AND SOUTHERN NEW YORK. AIRMASS ALREADY
QUITE UNSTABLE WITH SBCAPES OF 2500-3500 J/KG PER LATEST RAP AND
LAPS ANALYSIS. BASED ON SATELLITE TRENDS AND THE LACK OF
CONVECTIVE INHIBITION...EXPECT AN INCREASE IN COVERAGE OF SHOWERS
AND THUNDERSTORMS ACROSS NORTHERN NEW YORK THROUGH THE NEXT COUPLE
OF HOURS WITH THIS ACTIVITY DEVELOPING/SPREADING INTO VERMONT BY
LATE AFTERNOON/EVENING. NO CHANGES TO POPS/WEATHER AS THESE ARE
REFLECTED IN THE CURRENT FORECAST...AND STILL BELIEVE ENHANCED
WORDING FOR GUSTY WINDS AND HEAVY RAINFALL IS JUSTIFIED GIVEN
DEGREE OF INSTABILITY AND FAVORABLE DEEP- LAYER SHEAR PROFILES.
PLEASE SEE OUR RECENTLY ISSUED SPECIAL WEATHER STATEMENT TO RAISE
AWARENESS OF POTENTIALLY STRONG THUNDERSTORMS THIS AFTERNOON AND
EVENING.
ENDED UP RAISING TEMPERATURES UP A DEGREE BASED ON CURRENT TRENDS.
STILL EXPECT HIGHS TODAY IN THE UPPER 80S TO LOWER 90S WITH HEAT
INDICES IN THE MID/UPPER 90S.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH SATURDAY/...
AS OF 533 AM EDT THURSDAY...LINGERING CONVECTION THIS EVENING
WITH BR/FG DEVELOPING OVERNIGHT...ESP AT LOCATIONS THAT RECEIVE
RAINFALL. TOWARDS EARLY MORNING HOURS ON FRIDAY...NAM AND GFS
SHOW WARM FRONT LIFTING NWD...BEGINNING THREAT FOR SHOWERS AND
TSTMS EARLY. LLJ AROUND 30-45KTS WILL ACCOMPANY THE
FRONT...PROVIDING PLENTY OF SHEAR TO HELP ORGANIZE CONVECTION.
CAPE VALUES WILL BE EVEN HIGHER WITH OVER 2500 J/KG PSBL AND
SHOWALTER INDEX AROUND -3. CLEARLY DEFINE THETA E RIDGING
SUPPORTS INDICATIONS OF LARGE INSTABILITY OVER THE AREA. WARM
HUMID CONDITIONS CONTINUE ON FRIDAY...BUT FRONT WILL ALSO HAVE
SUPPORT FROM VORTICITY WHICH WILL CONTINUE TO MOVE OVER THE
REGION INTO THE OVERNIGHT. THEREFORE EXPECT BEST CHCS FOR
CONVECTION TO OCCUR ON FRIDAY INTO FRIDAY NIGHT AS MID LEVEL HT
FALLS SEE A MORE DRAMATIC CHANGE FRIDAY NIGHT WHILE UPPER LEVEL
TROUGH GAINS MOMENTUM EWD...GRAZING THE CENTRAL GREAT LAKES AND
PUSHING THE LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT AT THE
SFC FORWARD. GOING INTO SATURDAY...COLD FRONT WILL BE FOCUS OF
SHOWERS AND TSTMS...WITH CAPE OVER 1000 J/KG AND LI AROUND -3C.
UPPER LEVEL JET ACCOMPANYING THE FRONT WILL POSITION THE RR QUAD
OVER THE SLV FRIDAY NIGHT AND MOVE EWD THROUGHOUT THE DAY
SATURDAY. THE COLD FRONT DOESN/T LOOK TO EXIT ERN VT UNTIL LATE
SATURDAY INTO SATURDAY EVENING.
TEMPS WILL BE HOT WITH 925MB REACHING MID20S ON FRIDAY...
RESULTING IN SFC MAX TEMPS IN THE U80S-M90S...ESP IN SW DOWNSLOPE
AREAS LIKE PBG. HEAT INDEX VALUES WILL ONCE AGAIN APPROACH 100
DEGREES IN A FEW LOCATIONS MAINLY IN THE CPV AND CT VALLEY. WITH
MORE CLD COVER ON SATURDAY...EXPECT MAX TEMPS TO BE IN THE
M-U80S. OVERNIGHT MIN TEMPS WILL BE WARM...IN THE 60S- L70S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 407 AM EDT THURSDAY... IT WILL BE NOTICEABLY COOLER AND
DRIER SUNDAY AND MONDAY BEFORE RETURNING TO NEAR NORMAL TUESDAY
AND WEDNESDAY WITH A CHANCE OF SHOWERS AND THUNDERSTORMS.
A BROAD AREA OF CANADIAN HIGH PRESSURE SETTLES INTO THE REGION
SUNDAY INTO MONDAY. 850 TEMPS DROPS TO AROUND 6C BUT MODIFY BACK
TO 8-11C WITH DAYTIME HEATING SO MAX TEMPERATURES EXPECTED IN THE
70S ON SUNDAY AND NIGHTTIME LOWS IN THE 50S WITH KSLK PERHAPS MID
40S.
A BIT MORE UNCERTAIN BY TUE AND WED WITH TIMING OF SHORT WAVE
TROFS WHICH ARE EXPECTED TO CARVE OUT A MEAN LONGER WAVE AND
PERSISTENT TROF SOMEWHERE OVER FROM WESTERN GREAT LAKES INTO THE
NORTHEAST. WE WILL TEND TO BE ON THE ACTIVE SIDE OF THE TROF SO
HAVE BROUGHT A CHANCE OF SHOWERS AND SLIGHT CHANCE OF THUNDER
INTO THE AREA ON TUE-WED. ECMWF IS FASTER THAN GFS/GEFS SO HAVE
TWEAKED THE POPS UP INTO 30 PERCENT RANGE FOR NOW. TEMPERATURES
WILL CREEP UP TO AROUND NORMAL BUT IF IT`S SHOWERY DURING THE
DAY, IT COULD BE A BIT COOLER. LOWS MAINLY 55 TO 65 AND HIGHS 75
TO 82.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
THROUGH 18Z FRIDAY...VFR CONDITIONS WL PREVAIL THIS
AFTN/EVENING...EXCEPT BRIEF PERIODS OF MVFR IN AND AROUND
THUNDERSTORMS. ALSO...ANTICIPATED LIGHTNING AND LOCALIZED GUSTY
WINDS IN THE STRONGER STORMS BTWN 18Z-00Z TODAY. CRNT RADAR TRENDS
SHOW STORMS IMPACTING MSS BY 19Z...WITH OTHER STORMS DEVELOPING
ACRS THE EASTERN DACKS WITH POTENTIAL IMPACTS TO PBG/BTV AND MPV
BTWN 19Z-22Z. HAVE USED TEMPO GROUP TO SHOW 3SM TSRA WITH CIGS BKN
AT 2500 TO 3000 KFT. TONIGHT...AVIATION CHALLENGE WL BE FOG/BR
POTENTIAL...AS LLVL WINDS INCREASE. THINKING MPV/SLK WL HAVE THE
BEST POTENTIAL FOR IFR CONDITIONS AS LLVLS DECOUPLE WITH MVFR
POSSIBLE AT RUT/MSS/BTV...ESPECIALLY IF RAIN OCCURS AT THESE SITES
THIS AFTN.
SOUTH TO SOUTHWEST WINDS WL INCREASE AT 10 TO 15 KNOTS WITH GUSTS
TO 20 TO 25 KNOTS BY FRIDAY MID MORNING.
OUTLOOK 18Z FRIDAY THROUGH MONDAY...SCATTERED AFTN/EVENING
SHOWERS/STORMS AGAIN ON FRIDAY/SATURDAY COULD PRODUCE BRIEF
PERIODS OF MVFR/IFR CONDITIONS. IN ADDITION...GUSTY SOUTHWEST
WINDS AHEAD OF AN APPROACHING COLD FRNT WL CONT ON FRIDAY
AFTN/NIGHT...BEFORE SHIFTING TO THE NORTHWEST ON SAT AFTN.
SUNDAY AND MONDAY...VFR UNDER BUILDING HIGH PRESSURE...EXCEPT
FOG/BR WITH MVFR/IFR AT MPV/SLK EACH MORNING BTWN 06-11Z.
&&
.CLIMATE...
HEAT WAVE HAS BEEN REACHED WITH PAST 3 DAYS MEETING OR EXCEEDING
90F AT KBTV. EXPECT HEAT WAVE TO CONTINUE WITH MAX TEMP OF 90
TODAY AND 94 ON FRIDAY...BEFORE A COLD FRONT APPROACHES ON
SATURDAY.
MAX TEMP RECORDS TODAY THROUGH FRIDAY. BEST SHOT OF REACHING OR
BREAKING RECORD MAX TEMPS ON FRIDAY AT KMPV AND KMSS. SHORTER
PERIOD OF RECORD AT THESE SITES THAN AT K1V4 AND KBTV.
07/18/2013 07/19/2013
KBTV 99/1953 98/1942
KMPV 96/1953 92/1991
K1V4 99/1953 95/1991
KMSS 95/1953 93/1991
&&
.EQUIPMENT...
KTYX IS BACK TO NORMAL OPERATIONS. SLK ASOS IS DOWN DUE TO COMMS
ISSUES...ETS ARE HEADING TO THE SITE AND SHOULD BE FIXED BY MID
AFTERNOON. ALSO...RUTLAND AWOS WILL BE UNAVAIABLE FROM 18 TO 20
UTC TODAY.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...KGM/TABER
NEAR TERM...KGM/LOCONTO
SHORT TERM...KGM
LONG TERM...SISSON
AVIATION...TABER
CLIMATE...
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
108 PM EDT THU JUL 18 2013
.SYNOPSIS...
AN ACTIVE WEATHER PATTERN WILL CONTINUE ACROSS THE NORTH COUNTRY
WITH DAILY CHANCES FOR SCATTERED SHOWERS AND THUNDERSTORMS...
ALONG WITH HOT AND HUMID CONDITIONS THROUGH THE END OF THE WEEK.
SOME STORMS COULD BE STRONG TO SEVERE THROUGH THE PERIOD. A COLD
FRONT WILL MOVE THROUGH ON SATURDAY BRINGING MUCH DRIER AND
COOLER AIR FOR SUNDAY AND MONDAY.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
AS OF 107 PM EDT THURSDAY...VISIBLE SATELLITE SHOWS DEVELOPING
CUMULUS/TOWERING CUMULUS CLOUDS ACROSS THE HIGHER TERRAIN...WITH
SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING ACROSS EASTERN
ONTARIO AND IN CENTRAL AND SOUTHERN NEW YORK. AIRMASS ALREADY
QUITE UNSTABLE WITH SBCAPES OF 2500-3500 J/KG PER LATEST RAP AND
LAPS ANALYSES. BASED ON SATELLITE TRENDS AND THE LACK OF
CONVECTIVE INHIBITION...EXPECT AN INCREASE IN COVERAGE OF SHOWERS
AND THUNDERSTORMS ACROSS NORTHERN NEW YORK THROUGH THE NEXT COUPLE
OF HOURS WITH THIS ACTIVITY DEVELOPING/SPREADING INTO VERMONT BY
LATE AFTERNOON/EVENING. NO CHANGES TO POPS/WEATHER AS THESE ARE
REFLECTED IN THE CURRENT FORECAST...AND STILL BELIEVE ENHANCED
WORDING FOR GUSTY WINDS AND HEAVY RAINFALL IS JUSTIFIED GIVEN
DEGREE OF INSTABILITY AND FAVORABLE DEEP- LAYER SHEAR PROFILES.
PLEASE SEE OUR RECENTLY ISSUED SPECIAL WEATHER STATEMENT TO RAISE
AWARENESS OF POTENTIALLY STRONG THUNDERSTORMS THIS AFTERNOON AND
EVENING.
ENDED UP RAISING TEMPERATURES UP A DEGREE BASED ON CURRENT TRENDS.
STILL EXPECT HIGHS TODAY IN THE UPPER 80S TO LOWER 90S WITH HEAT
INDICES IN THE MID/UPPER 90S.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH SATURDAY/...
AS OF 533 AM EDT THURSDAY...LINGERING CONVECTION THIS EVENING
WITH BR/FG DEVELOPING OVERNIGHT...ESP AT LOCATIONS THAT RECEIVE
RAINFALL. TOWARDS EARLY MORNING HOURS ON FRIDAY...NAM AND GFS
SHOW WARM FRONT LIFTING NWD...BEGINNING THREAT FOR SHOWERS AND
TSTMS EARLY. LLJ AROUND 30-45KTS WILL ACCOMPANY THE
FRONT...PROVIDING PLENTY OF SHEAR TO HELP ORGANIZE CONVECTION.
CAPE VALUES WILL BE EVEN HIGHER WITH OVER 2500 J/KG PSBL AND
SHOWALTER INDEX AROUND -3. CLEARLY DEFINE THETA E RIDGING
SUPPORTS INDICATIONS OF LARGE INSTABILITY OVER THE AREA. WARM
HUMID CONDITIONS CONTINUE ON FRIDAY...BUT FRONT WILL ALSO HAVE
SUPPORT FROM VORTICITY WHICH WILL CONTINUE TO MOVE OVER THE
REGION INTO THE OVERNIGHT. THEREFORE EXPECT BEST CHCS FOR
CONVECTION TO OCCUR ON FRIDAY INTO FRIDAY NIGHT AS MID LEVEL HT
FALLS SEE A MORE DRAMATIC CHANGE FRIDAY NIGHT WHILE UPPER LEVEL
TROUGH GAINS MOMENTUM EWD...GRAZING THE CENTRAL GREAT LAKES AND
PUSHING THE LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT AT THE
SFC FORWARD. GOING INTO SATURDAY...COLD FRONT WILL BE FOCUS OF
SHOWERS AND TSTMS...WITH CAPE OVER 1000 J/KG AND LI AROUND -3C.
UPPER LEVEL JET ACCOMPANYING THE FRONT WILL POSITION THE RR QUAD
OVER THE SLV FRIDAY NIGHT AND MOVE EWD THROUGHOUT THE DAY
SATURDAY. THE COLD FRONT DOESN/T LOOK TO EXIT ERN VT UNTIL LATE
SATURDAY INTO SATURDAY EVENING.
TEMPS WILL BE HOT WITH 925MB REACHING MID20S ON FRIDAY...
RESULTING IN SFC MAX TEMPS IN THE U80S-M90S...ESP IN SW DOWNSLOPE
AREAS LIKE PBG. HEAT INDEX VALUES WILL ONCE AGAIN APPROACH 100
DEGREES IN A FEW LOCATIONS MAINLY IN THE CPV AND CT VALLEY. WITH
MORE CLD COVER ON SATURDAY...EXPECT MAX TEMPS TO BE IN THE
M-U80S. OVERNIGHT MIN TEMPS WILL BE WARM...IN THE 60S- L70S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 407 AM EDT THURSDAY... IT WILL BE NOTICEABLY COOLER AND
DRIER SUNDAY AND MONDAY BEFORE RETURNING TO NEAR NORMAL TUESDAY
AND WEDNESDAY WITH A CHANCE OF SHOWERS AND THUNDERSTORMS.
A BROAD AREA OF CANADIAN HIGH PRESSURE SETTLES INTO THE REGION
SUNDAY INTO MONDAY. 850 TEMPS DROPS TO AROUND 6C BUT MODIFY BACK
TO 8-11C WITH DAYTIME HEATING SO MAX TEMPERATURES EXPECTED IN THE
70S ON SUNDAY AND NIGHTTIME LOWS IN THE 50S WITH KSLK PERHAPS MID
40S.
A BIT MORE UNCERTAIN BY TUE AND WED WITH TIMING OF SHORT WAVE
TROFS WHICH ARE EXPECTED TO CARVE OUT A MEAN LONGER WAVE AND
PERSISTENT TROF SOMEWHERE OVER FROM WESTERN GREAT LAKES INTO THE
NORTHEAST. WE WILL TEND TO BE ON THE ACTIVE SIDE OF THE TROF SO
HAVE BROUGHT A CHANCE OF SHOWERS AND SLIGHT CHANCE OF THUNDER
INTO THE AREA ON TUE-WED. ECMWF IS FASTER THAN GFS/GEFS SO HAVE
TWEAKED THE POPS UP INTO 30 PERCENT RANGE FOR NOW. TEMPERATURES
WILL CREEP UP TO AROUND NORMAL BUT IF IT`S SHOWERY DURING THE
DAY, IT COULD BE A BIT COOLER. LOWS MAINLY 55 TO 65 AND HIGHS 75
TO 82.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
THROUGH 00Z FRIDAY...MAINLY VFR AT KBTV/KPBG. OTHER SITES WILL
HAVE SOME IFR IN BR AND VLIFR AT TIMES IN FOG THROUGH 12Z AT KSLK
AND KMPV. FOG WILL BURN OFF 12-14Z.
NOT EXPECTING TOO MUCH IN THE WAY OF SHOWERS OR THUNDER UNTIL
SCATTERED THUNDERSTORMS DEVELOP GENERALLY AFTER 17Z AND HAVE
INCLUDED VCTS. IF A THUNDERSTORM WERE TO MOVE OVER A TAF SITE I
WOULD EXPECT BRIEF IFR VSBYS AND MVFR CIGS BUT TOO UNCERTAIN TO
INCLUDE AT THIS TIME OF DAY.
CONVECTION EXPECTED TO GRADUALLY DIE OFF TOMORROW NIGHT WITH SOME
BR EXPECTED AFTER 03Z.
WINDS LGT/VAR..THEN W-SW 5-10KTS FROM 13Z-14Z THURSDAY ONWARD.
OUTLOOK 06Z FRIDAY THROUGH MONDAY... 06Z FRIDAY - SAT LCL IFR
FG/BR OVERNIGHT...MAINLY AT KSLK/KMPV. SCATTERED MAINLY AFTERNOON
SHOWERS/THUNDERSTORMS BUT CANT RULE IT OUT AT ANY TIME THROUGH
SAT WITH BRIEF MVFR/IFR VISIBILITIES.
SUNDAY AND MONDAY...VFR UNDER BUILDING HIGH PRESSURE.
&&
.CLIMATE...
HEAT WAVE HAS BEEN REACHED WITH PAST 3 DAYS MEETING OR EXCEEDING
90F AT KBTV. EXPECT HEAT WAVE TO CONTINUE WITH MAX TEMP OF 90
TODAY AND 94 ON FRIDAY...BEFORE A COLD FRONT APPROACHES ON
SATURDAY.
MAX TEMP RECORDS TODAY THROUGH FRIDAY. BEST SHOT OF REACHING OR
BREAKING RECORD MAX TEMPS ON FRIDAY AT KMPV AND KMSS. SHORTER
PERIOD OF RECORD AT THESE SITES THAN AT K1V4 AND KBTV.
07/18/2013 07/19/2013
KBTV 99/1953 98/1942
KMPV 96/1953 92/1991
K1V4 99/1953 95/1991
KMSS 95/1953 93/1991
&&
.EQUIPMENT...
KTYX RADAR FUNCTIONING BUT WE MUST MAINTAIN VCP21 THROUGH AT LEAST THIS
MORNING OR UNTIL A SOLUTION IS FOUND BY THE TECHNICIANS FROM FORT
DRUM.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...KGM/TABER
NEAR TERM...KGM/LOCONTO
SHORT TERM...KGM
LONG TERM...SISSON
AVIATION...SISSON
CLIMATE...
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1015 AM EDT THU JUL 18 2013
.SYNOPSIS...
AN ACTIVE WEATHER PATTERN WILL CONTINUE ACROSS THE NORTH COUNTRY
WITH DAILY CHANCES FOR SCATTERED SHOWERS AND THUNDERSTORMS...
ALONG WITH HOT AND HUMID CONDITIONS THROUGH THE END OF THE WEEK.
SOME STORMS COULD BE STRONG TO SEVERE THROUGH THE PERIOD. A COLD
FRONT WILL MOVE THROUGH ON SATURDAY BRINGING MUCH DRIER AND
COOLER AIR FOR SUNDAY AND MONDAY.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
AS OF 1015 AM EDT THURSDAY...SOME CHANGES WERE MADE TO POPS THIS
MORNING & AFTERNOON AS WELL AS SOME UPWARD TWEAKS TO HOURLY
TEMPERATURES. SEVERAL HIGHLIGHTS TODAY INCLUDING CONTINUED
HOT/HUMID WEATHER AND POTENTIAL FOR STRONG CONVECTION AGAIN THIS
AFTERNOON.
CURRENT RADAR SHOWS SOME ISOLATED SHOWERS ACROSS SOUTHERN
QUEBEC FORMING ALONG A DIFFUSE THERMAL/MOISTURE BOUNDARY NEAR THE
INTERNATIONAL BORDER. THESE SHOWERS MAY SKIRT OUR NORTHERN VT AND
NORTHERN NY COUNTIES THROUGH THE MORNING HOURS. ASIDE FROM THAT
HOWEVER...WEAK SHORTWAVE RIDGING ACROSS THE SOUTHERN TWO-THIRDS OF
THE NORTH COUNTRY WILL KEEP THE REST OF THE NORTH COUNTRY DRY
THROUGH THE REST OF THE MORNING. FOR THE AFTERNOON...THE
AFOREMENTIONED SHORTWAVE RIDGE SHIFTS EAST AS A SUBTLE SHORTWAVE
TROUGH NOW ACROSS THE NORTHERN GREAT LAKES WILL APPROACH THE
REGION FROM THE WEST. THIS IS ALREADY PRODUCING CONVECTION ACROSS
THE NORTHERN LAKES...AND SEE LITTLE REASON TO THINK ADDITIONAL
CONVECTIVE DEVELOPMENT INTO OUR AREA THIS AFTERNOON WON`T HAPPEN
AS THIS TROUGH APPROACHES GIVEN PROJECTED SBCAPES IN THE
1500-3000 J/KG RANGE /HIGHEST WITH SOUTHERN AND WESTERN EXTENT/.
STILL HAVE 0-6KM SHEAR MAGNITUDES OF 30-40KTS AS WELL SO POTENTIAL
FOR SOME STORMS TO BECOME STRONG DURING THE AFTERNOON HOURS. SPC
HAS PLACED MUCH OF NORTHERN NEW YORK AND THE CHAMPLAIN VALLEY IN
A SLIGHT RISK FOR SEVERE THUNDERSTORMS. THOUGH CONVECTIVE MODE IS
TOUGH TO PIN DOWN...SHORT-RANGE REFLECTIVITY GUIDANCE SUGGESTS MOST
OF THE STORMS THAT DEVELOP INITIALLY IN NORTHERN NEW YORK LIFT INTO
NORTHERN/CENTRAL VT LATE IN THE AFTERNOON/EARLY EVENING. SO HAVE
KEPT SCATTERED THUNDERSTORMS WITH GUSTY WINDS AND HEAVY RAINFALL
WORDING IN THE FORECAST FOR THE AFTERNOON.
REGARDING TEMPERATURES...ALREADY STARTING OFF IN THE 70S TO LOW
80S. THOUGH THIS WOULD SUGGEST UPPING HIGHS A COUPLE DEGREES...FEEL
THAT INCREASING MID CLOUD COVER NOW OVER THE NORTHERN LAKES WILL
SPREAD INTO THE NORTH COUNTRY TOWARDS THE AFTERNOON WILL LIKELY
KEEP TEMPERATURES SLIGHTLY COOLER THAN YESTERDAY. THINK CURRENT
HIGHS LOOK ON TRACK WITH THE PROJECTED INCREASE IN CLOUDS BY THE
AFTERNOON. NONETHELESS...STILL WILL BE HOT AND HUMID WITH APPARENT
TEMPERATURES IN THE MID/UPPER 90S.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH SATURDAY/...
AS OF 533 AM EDT THURSDAY...LINGERING CONVECTION THIS EVENING
WITH BR/FG DEVELOPING OVERNIGHT...ESP AT LOCATIONS THAT RECEIVE
RAINFALL. TOWARDS EARLY MORNING HOURS ON FRIDAY...NAM AND GFS
SHOW WARM FRONT LIFTING NWD...BEGINNING THREAT FOR SHOWERS AND
TSTMS EARLY. LLJ AROUND 30-45KTS WILL ACCOMPANY THE
FRONT...PROVIDING PLENTY OF SHEAR TO HELP ORGANIZE CONVECTION.
CAPE VALUES WILL BE EVEN HIGHER WITH OVER 2500 J/KG PSBL AND
SHOWALTER INDEX AROUND -3. CLEARLY DEFINE THETA E RIDGING
SUPPORTS INDICATIONS OF LARGE INSTABILITY OVER THE AREA. WARM
HUMID CONDITIONS CONTINUE ON FRIDAY...BUT FRONT WILL ALSO HAVE
SUPPORT FROM VORTICITY WHICH WILL CONTINUE TO MOVE OVER THE
REGION INTO THE OVERNIGHT. THEREFORE EXPECT BEST CHCS FOR
CONVECTION TO OCCUR ON FRIDAY INTO FRIDAY NIGHT AS MID LEVEL HT
FALLS SEE A MORE DRAMATIC CHANGE FRIDAY NIGHT WHILE UPPER LEVEL
TROUGH GAINS MOMENTUM EWD...GRAZING THE CENTRAL GREAT LAKES AND
PUSHING THE LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT AT THE
SFC FORWARD. GOING INTO SATURDAY...COLD FRONT WILL BE FOCUS OF
SHOWERS AND TSTMS...WITH CAPE OVER 1000 J/KG AND LI AROUND -3C.
UPPER LEVEL JET ACCOMPANYING THE FRONT WILL POSITION THE RR QUAD
OVER THE SLV FRIDAY NIGHT AND MOVE EWD THROUGHOUT THE DAY
SATURDAY. THE COLD FRONT DOESN/T LOOK TO EXIT ERN VT UNTIL LATE
SATURDAY INTO SATURDAY EVENING.
TEMPS WILL BE HOT WITH 925MB REACHING MID20S ON FRIDAY...
RESULTING IN SFC MAX TEMPS IN THE U80S-M90S...ESP IN SW DOWNSLOPE
AREAS LIKE PBG. HEAT INDEX VALUES WILL ONCE AGAIN APPROACH 100
DEGREES IN A FEW LOCATIONS MAINLY IN THE CPV AND CT VALLEY. WITH
MORE CLD COVER ON SATURDAY...EXPECT MAX TEMPS TO BE IN THE
M-U80S. OVERNIGHT MIN TEMPS WILL BE WARM...IN THE 60S- L70S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 407 AM EDT THURSDAY... IT WILL BE NOTICEABLY COOLER AND
DRIER SUNDAY AND MONDAY BEFORE RETURNING TO NEAR NORMAL TUESDAY
AND WEDNESDAY WITH A CHANCE OF SHOWERS AND THUNDERSTORMS.
A BROAD AREA OF CANADIAN HIGH PRESSURE SETTLES INTO THE REGION
SUNDAY INTO MONDAY. 850 TEMPS DROPS TO AROUND 6C BUT MODIFY BACK
TO 8-11C WITH DAYTIME HEATING SO MAX TEMPERATURES EXPECTED IN THE
70S ON SUNDAY AND NIGHTTIME LOWS IN THE 50S WITH KSLK PERHAPS MID
40S.
A BIT MORE UNCERTAIN BY TUE AND WED WITH TIMING OF SHORT WAVE
TROFS WHICH ARE EXPECTED TO CARVE OUT A MEAN LONGER WAVE AND
PERSISTENT TROF SOMEWHERE OVER FROM WESTERN GREAT LAKES INTO THE
NORTHEAST. WE WILL TEND TO BE ON THE ACTIVE SIDE OF THE TROF SO
HAVE BROUGHT A CHANCE OF SHOWERS AND SLIGHT CHANCE OF THUNDER
INTO THE AREA ON TUE-WED. ECMWF IS FASTER THAN GFS/GEFS SO HAVE
TWEAKED THE POPS UP INTO 30 PERCENT RANGE FOR NOW. TEMPERATURES
WILL CREEP UP TO AROUND NORMAL BUT IF IT`S SHOWERY DURING THE
DAY, IT COULD BE A BIT COOLER. LOWS MAINLY 55 TO 65 AND HIGHS 75
TO 82.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
THROUGH 00Z FRIDAY...MAINLY VFR AT KBTV/KPBG. OTHER SITES WILL
HAVE SOME IFR IN BR AND VLIFR AT TIMES IN FOG THROUGH 12Z AT KSLK
AND KMPV. FOG WILL BURN OFF 12-14Z.
NOT EXPECTING TOO MUCH IN THE WAY OF SHOWERS OR THUNDER UNTIL
SCATTERED THUNDERSTORMS DEVELOP GENERALLY AFTER 17Z AND HAVE
INCLUDED VCTS. IF A THUNDERSTORM WERE TO MOVE OVER A TAF SITE I
WOULD EXPECT BRIEF IFR VSBYS AND MVFR CIGS BUT TOO UNCERTAIN TO
INCLUDE AT THIS TIME OF DAY.
CONVECTION EXPECTED TO GRADUALLY DIE OFF TOMORROW NIGHT WITH SOME
BR EXPECTED AFTER 03Z.
WINDS LGT/VAR..THEN W-SW 5-10KTS FROM 13Z-14Z THURSDAY ONWARD.
OUTLOOK 06Z FRIDAY THROUGH MONDAY... 06Z FRIDAY - SAT LCL IFR
FG/BR OVERNIGHT...MAINLY AT KSLK/KMPV. SCATTERED MAINLY AFTERNOON
SHOWERS/THUNDERSTORMS BUT CANT RULE IT OUT AT ANY TIME THROUGH
SAT WITH BRIEF MVFR/IFR VISIBILITIES.
SUNDAY AND MONDAY...VFR UNDER BUILDING HIGH PRESSURE.
&&
.CLIMATE...
HEAT WAVE HAS BEEN REACHED WITH PAST 3 DAYS MEETING OR EXCEEDING
90F AT KBTV. EXPECT HEAT WAVE TO CONTINUE WITH MAX TEMP OF 90
TODAY AND 94 ON FRIDAY...BEFORE A COLD FRONT APPROACHES ON
SATURDAY.
MAX TEMP RECORDS TODAY THROUGH FRIDAY. BEST SHOT OF REACHING OR
BREAKING RECORD MAX TEMPS ON FRIDAY AT KMPV AND KMSS. SHORTER
PERIOD OF RECORD AT THESE SITES THAN AT K1V4 AND KBTV.
07/18/2013 07/19/2013
KBTV 99/1953 98/1942
KMPV 96/1953 92/1991
K1V4 99/1953 95/1991
KMSS 95/1953 93/1991
&&
.EQUIPMENT...
KTYX RADAR FUNCTIONING BUT WE MUST MAINTAIN VCP21 THROUGH AT LEAST THIS
MORNING OR UNTIL A SOLUTION IS FOUND BY THE TECHNICIANS FROM FORT
DRUM.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...KGM/TABER
NEAR TERM...KGM/LOCONTO
SHORT TERM...KGM
LONG TERM...SISSON
AVIATION...SISSON
CLIMATE...
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
533 AM EDT THU JUL 18 2013
.SYNOPSIS...
AN ACTIVE WEATHER PATTERN WILL CONTINUE ACROSS THE NORTH COUNTRY
WITH DAILY CHANCES FOR SCATTERED SHOWERS AND THUNDERSTORMS...
ALONG WITH HOT AND HUMID CONDITIONS THROUGH THE END OF THE WEEK.
SOME STORMS COULD BE STRONG TO SEVERE THROUGH THE PERIOD. A COLD
FRONT WILL MOVE THROUGH ON SATURDAY BRINGING MUCH DRIER AND
COOLER AIR FOR SUNDAY AND MONDAY.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
AS OF 533 AM EDT THURSDAY...QUIET START TO THE DAY AS HIGH
PRESSURE REMAINS OVER THE MISSISSIPPI AND MISSOURI
VALLEYS...KEEPING THE NORTH COUNTRY IN FAIRLY ZONAL W-NW FLOW
ALOFT. HOT AND HUMID CONDITIONS CONTINUE TODAY...WITH INSTABILITY
AND MOSTLY CLEAR TO PARTLY CLOUDY SKIES ALLOWING FOR LOTS OF
DIURNAL HEATING...COMBINED WITH MIXED LAYER CAPE VALUES OF
1500+J/KG...LI OF -5C TO -7C...0-6KM SHEAR OF 30-40KTS WILL
TRIGGER SHOWERS AND THUNDERSTORMS THIS AFTN...WITH NAM AND GFS
INDICATING A SLGT WAVE/WARM FRONT AT THE SFC WHICH COULD HELP
KEEP CONVECTION LINGER INTO THE OVERNIGHT. THETA E GRADIENT TO
OUR NORTH IN SW QUEBEC...ALONG WITH UPPER LEVEL JET DYNAMICS
BEING TO THE NORTH WILL HAVE CONVECTION RELY ON DIURNAL HEATING.
WITHOUT NOTABLE SYNOPTIC FORCING...EXPECT CONVECTION TO START IN
THE EARLY/MID AFTN...ESP OVER HIGHER TRRN...WITH GUSTY WINDS AND
HEAVY DOWNPOURS AS PWATS WILL BE 1.5-2 INCHES. LIKELY TO BE SOME
LINGERING SHOWERS AND TSTMS THROUGH MIDNIGHT...BUT OVERALL
COVERAGE WILL BEGIN TO WANE AFTER 00Z.
HOT MUGGY DAY ON TAP WITH MAX TEMPS REACHING THE L90S IN THE
VALLEYS AND 70S IN THE HIGH TRRN. DEWPTS EXPECTED TO BE IN THE
M60S TO M70S. HEAT INDEX VALUES WILL APPROACH 100F DURING THE
PEAK DAYTIME HEATING.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH SATURDAY/...
AS OF 533 AM EDT THURSDAY...LINGERING CONVECTION THIS EVENING
WITH BR/FG DEVELOPING OVERNIGHT...ESP AT LOCATIONS THAT RECEIVE
RAINFALL. TOWARDS EARLY MORNING HOURS ON FRIDAY...NAM AND GFS
SHOW WARM FRONT LIFTING NWD...BEGINNING THREAT FOR SHOWERS AND
TSTMS EARLY. LLJ AROUND 30-45KTS WILL ACCOMPANY THE
FRONT...PROVIDING PLENTY OF SHEAR TO HELP ORGANIZE CONVECTION.
CAPE VALUES WILL BE EVEN HIGHER WITH OVER 2500 J/KG PSBL. CLEARLY
DEFINE THETA E RIDGING SUPPORTS INDICATIONS OF LARGE INSTABILITY
OVER THE AREA. WARM HUMID CONDITIONS CONTINUE ON FRIDAY...BUT
FRONT WILL ALSO HAVE SUPPORT FROM VORTICITY WHICH WILL CONTINUE
TO MOVE OVER THE REGION INTO THE OVERNIGHT. THEREFORE EXPECT BEST
CHCS FOR CONVECTION TO OCCUR ON FRIDAY INTO FRIDAY NIGHT AS MID
LEVEL HT FALLS SEE A MORE DRAMATIC CHANGE FRIDAY NIGHT WHILE
UPPER LEVEL TROUGH GAINS MOMENTUM EWD...GRAZING THE CENTRAL GREAT
LAKES AND PUSHING THE LOW PRESSURE SYSTEM AND ASSOCIATED COLD
FRONT AT THE SFC FORWARD. GOING INTO SATURDAY...COLD FRONT WILL
BE FOCUS OF SHOWERS AND TSTMS...WITH CAPE OVER 1000 J/KG AND LI
AROUND -3C. UPPER LEVEL JET ACCOMPANYING THE FRONT WILL POSITION
THE RR QUAD OVER THE SLV FRIDAY NIGHT AND MOVE EWD THROUGHOUT THE
DAY SATURDAY. THE COLD FRONT DOESN/T LOOK TO EXIT ERN VT UNTIL
LATE SATURDAY INTO SATURDAY EVENING.
TEMPS WILL BE HOT WITH 925MB REACHING MID20S ON FRIDAY...
RESULTING IN SFC MAX TEMPS IN THE U80S-M90S...ESP IN SW DOWNSLOPE
AREAS LIKE PBG. HEAT INDEX VALUES WILL ONCE AGAIN APPROACH 100
DEGREES IN A FEW LOCATIONS MAINLY IN THE CPV AND CT VALLEY. WITH
MORE CLD COVER ON SATURDAY...EXPECT MAX TEMPS TO BE IN THE
M-U80S. OVERNIGHT MIN TEMPS WILL BE WARM...IN THE 60S- L70S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 407 AM EDT THURSDAY... IT WILL BE NOTICEABLY COOLER AND
DRIER SUNDAY AND MONDAY BEFORE RETURNING TO NEAR NORMAL TUESDAY
AND WEDNESDAY WITH A CHANCE OF SHOWERS AND THUNDERSTORMS.
A BROAD AREA OF CANADIAN HIGH PRESSURE SETTLES INTO THE REGION
SUNDAY INTO MONDAY. 850 TEMPS DROPS TO AROUND 6C BUT MODIFY BACK
TO 8-11C WITH DAYTIME HEATING SO MAX TEMPERATURES EXPECTED IN THE
70S ON SUNDAY AND NIGHTTIME LOWS IN THE 50S WITH KSLK PERHAPS MID
40S.
A BIT MORE UNCERTAIN BY TUE AND WED WITH TIMING OF SHORT WAVE
TROFS WHICH ARE EXPECTED TO CARVE OUT A MEAN LONGER WAVE AND
PERSISTENT TROF SOMEWHERE OVER FROM WESTERN GREAT LAKES INTO THE
NORTHEAST. WE WILL TEND TO BE ON THE ACTIVE SIDE OF THE TROF SO
HAVE BROUGHT A CHANCE OF SHOWERS AND SLIGHT CHANCE OF THUNDER
INTO THE AREA ON TUE-WED. ECMWF IS FASTER THAN GFS/GEFS SO HAVE
TWEAKED THE POPS UP INTO 30 PERCENT RANGE FOR NOW. TEMPERATURES
WILL CREEP UP TO AROUND NORMAL BUT IF IT`S SHOWERY DURING THE
DAY, IT COULD BE A BIT COOLER. LOWS MAINLY 55 TO 65 AND HIGHS 75
TO 82.
&&
.AVIATION /09Z THURSDAY THROUGH MONDAY/...
THROUGH 00Z FRIDAY...MAINLY VFR AT KBTV/KPBG. OTHER SITES WILL
HAVE SOME IFR IN BR AND VLIFR AT TIMES IN FOG THROUGH 12Z AT KSLK
AND KMPV. FOG WILL BURN OFF 12-14Z.
NOT EXPECTING TOO MUCH IN THE WAY OF SHOWERS OR THUNDER UNTIL
SCATTERED THUNDERSTORMS DEVELOP GENERALLY AFTER 17Z AND HAVE
INCLUDED VCTS. IF A THUNDERSTORM WERE TO MOVE OVER A TAF SITE I
WOULD EXPECT BRIEF IFR VSBYS AND MVFR CIGS BUT TOO UNCERTAIN TO
INCLUDE AT THIS TIME OF DAY.
CONVECTION EXPECTED TO GRADUALLY DIE OFF TOMORROW NIGHT WITH SOME
BR EXPECTED AFTER 03Z.
WINDS LGT/VAR..THEN W-SW 5-10KTS FROM 13Z-14Z THURSDAY ONWARD.
OUTLOOK 06Z FRIDAY THROUGH MONDAY... 06Z FRIDAY - SAT LCL IFR
FG/BR OVERNIGHT...MAINLY AT KSLK/KMPV. SCATTERED MAINLY AFTERNOON
SHOWERS/THUNDERSTORMS BUT CANT RULE IT OUT AT ANY TIME THROUGH
SAT WITH BRIEF MVFR/IFR VISIBILITIES.
SUNDAY AND MONDAY...VFR UNDER BUILDING HIGH PRESSURE.
&&
.CLIMATE...
MAX TEMP RECORDS TODAY THROUGH FRIDAY. BEST SHOT OF REACHING OR
BREAKING RECORD MAX TEMPS ON FRIDAY AT KMPV AND KMSS. SHORTER
PERIOD OF RECORD AT THESE SITES THAN AT K1V4 AND KBTV.
07/18/2013 07/19/2013
KBTV 99/1953 98/1942
KMPV 96/1953 92/1991
K1V4 99/1953 95/1991
KMSS 95/1953 93/1991
&&
.EQUIPMENT...
KTYX RADAR FUNCTIONING BUT WE MUST MAINTAIN VCP21 THROUGH AT LEAST THIS
MORNING OR UNTIL A SOLUTION IS FOUND BY THE TECHNICIANS FROM FORT
DRUM.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...KGM/TABER
NEAR TERM...KGM
SHORT TERM...KGM
LONG TERM...SISSON
AVIATION...SISSON
CLIMATE...WFO STAFF
EQUIPMENT...WFO STAFF
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
100 PM EDT THU JUL 18 2013
.SYNOPSIS...
A WEAK TROUGH OF LOW PRESSURE WILL RESIDE ACROSS THE CAROLINA
INTERIOR INTO THE WEEKEND...WHILE BERMUDA HIGH PRESSURE NUDGES
INTO THE REGION FROM THE WESTERN ATLANTIC. A SLOW MOVING COLD FRONT
WILL STALL ACROSS THE AREA EARLY NEXT WEEK...INCREASING THE CHANCE
OF SHOWERS AND STORMS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 10 AM THURSDAY...CLOCKWISE TURNING OF THE ATMOSPHERE AND
DRIER AIR HAS WORKED INTO THE FORECAST AREA IN THE LAST 12 HOURS
AS AN UPPER RIDGE CONTINUES TO NUDGE EASTWARD. PRECIPITABLE WATER
VALUES HAVE DECREASED OVER A HALF INCH SINCE THIS TIME YESTERDAY
AND SUBSIDENT DOWNWARD MOTION PREVAILS CURRENTLY. THUNDERSTORMS
TO BE CONSIDERABLY MORE HINDERED TODAY...WITH MUCH LESS COVERAGE
AND INTENSITY ANTICIPATED. SEVERAL OF OUR MORE USEFUL NEAR TERM
MODELS SUCH AS THE 3KM HRRR AND 4KM NSSL WRF PAINT SIMILAR OUTCOMES
TODAY...GENERATING ISOLATED TO SCATTERED CONVECTION BETWEEN 2PM AND
3PM INLAND FROM THE COAST...PEAKING IN INTENSITY IN THE LATE AFTN
THEN WEAKENING RAPIDLY WITH DIMINISHED SURFACE HEATING INTO EARLY
EVENING. THIS APPEARS REASONABLE GIVEN THE LACKLUSTER INGREDIENTS
IN PLACE. VAPOR ANALYSIS SHOWS A LOCALLY HIGHER SLUG OF COLUMN
MOISTURE BEING GUIDED INTO COASTAL SOUTH CAROLINA AND THIS MAY
ALLOW MORE ACTIVITY LATER TODAY ACROSS OUR VERY SOUTHERN TIER.
NO MAJOR CHANGES PLANNED TO THE ONGOING FORECAST...AND BECAUSE
OF SLIGHTLY LOWER SFC DEWPOINTS TODAY...HEAT INDICES SHOULD HOLD
MOSTLY BELOW 100...HIGHEST INLAND ASSOCIATED WITH A STRONGER
THERMAL AXIS ALONG THE SANDHILLS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 330 AM THURSDAY...ELONGATED RIDGE IN THE MID TO UPPER
LEVELS EXTENDING FROM THE CAROLINAS ACROSS THE TENNESSEE VALLEY
INTO THE DESERT SOUTHWEST WILL WEAKEN OVER THE EAST THROUGH THE
PERIOD AS TROUGH BEGINS TO DIG DOWN FROM CANADA OVER THE WEEKEND.
BERMUDA RIDGE WILL EXTEND WESTWARD INTO THE CAROLINAS FROM THE
SURFACE UP THROUGH THE LOWER LEVELS OF THE ATMOSPHERE. AT THE SAME
TIME THE PIEDMONT TROUGH REMAINS PRONOUNCED INLAND. THIS WILL
PRODUCE A TIGHTENED GRADIENT FLOW OUT OF THE SOUTH TO SOUTHWEST
FRI INTO SATURDAY. THERE SHOULD BE ENOUGH SUBSIDENCE AND DRY AIR
THROUGH THE MID LEVELS TO HELP SUPPRESS ANY WIDESPREAD CONVECTION
ACROSS THE AREA FRI INTO THE FIRST HALF OF THE WEEKEND. AS THE
RIDGE SHIFTS FARTHER SOUTH THROUGH THE MID TO UPPER LEVELS THE
FLOW ALOFT WILL BEGIN TO SHIFT FROM EASTERLY ON FRI TO NORTH
NORTHWEST FRI NIGHT INTO SATURDAY AND EVENTUALLY WESTERLY BY SAT
NIGHT. THIS WILL ALLOW INCREASING MOISTURE TO ADVECT IN BY THE END
OF THE PERIOD AND WILL ALSO STEER CLOUDS AND SHWRS/TSTMS THAT
DEVELOP INLAND TOWARD THE COAST LATE SATURDAY. THE SOUTHWEST
COMPONENT OF THE FLOW IN THE LOW LEVELS WILL KEEP SEA BREEZE FROM
DRIVING TOO FAR INLAND BY SATURDAY. THIS WILL INCREASE CHC OF
SHOWERS CLOSER TO THE COAST ON SATURDAY BUT OVERALL EXPECT MORE
LIMITED SHWR ACTIVITY THROUGH MUCH OF THE PERIOD. TEMPS WILL
REMAIN VERY WARM TYPICAL OF MID SUMMER WITH READINGS AROUND 90
DURING THE DAY AND LOW TO MID 70S AT NIGHT MOST PLACES.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 330 AM THURSDAY...MORE ACTIVE WEATHER EXPECTED EARLY TO MID
WEEK NEXT WEEK. MID TO UPPER TROUGH WILL CONTINUE TO PUSH A COLD
FRONT TOWARD THE CAROLINAS THROUGH EARLY NEXT WEEK. INCREASING
INSTABILITY AND MOISTURE AHEAD OF THIS FRONT WILL COMBINE WITH
BETTER UPPER LEVEL DYNAMICS TO PRODUCE MORE WIDESPREAD SHWR/TSTMS
ACTIVITY THROUGH THE PERIOD. STILL SOMEWHAT UNCERTAIN AS TO HOW
FAR THE FRONT WILL MAKE IT BUT LATEST GFS SHOWS THIS BOUNDARY
REACHING INTO NORTH CAROLINA BY EARLY MONDAY AND POSSIBLY
REMAINING OVER THE CAROLINAS THROUGH MID WEEK. DECENT MID TO UPPER
LEVEL SHORTWAVE ENERGY WILL RIDE THROUGH LONGER WAVE TROUGH
REACHING DOWN FROM CANADA THROUGH EARLY TO MID WEEK. THIS WILL
ENHANCE SHWR/TSTM ACTIVITY EACH DAY. INCREASED CLOUDINESS AND
CONVECTION WILL LEAD TO FLUCTUATIONS IN TEMPS THROUGH THE DAY BUT
OVERALL EXPECT READINGS RIGHT NEAR OR ABOVE NORMAL...AROUND 90
DURING THE DAY AND HOLDING IN THE LOWER TO MID 70S OVERNIGHT.
&&
.AVIATION /18Z THURSDAY THROUGH MONDAY/...
AS OF 17Z...ISOLATED CONVECTION WILL FIRE OVER PORTIONS OF THE CWA
THIS AFTERNOON. THE COAST WILL LIKELY BE SPARED...WITH ONLY ISOLATED
CONVECTION INLAND. WILL GO WITH A VCSH MENTION ONLY. LIGHT SOUTHERLY
FLOW...A BIT MORE SOUTHEASTERLY ALONG THE COAST. LIGHT WINDS TONIGHT
WITH SOME MVFR FOG EXPECTED BY AFTER 08Z. WINDS ALOFT WILL BE A BIT
STRONGER THAN YESTERDAY...SO DUE NOT EXPECT ANY DENSE FOG. LIGHT
SOUTHWESTERLY FLOW EXPECTED FRIDAY WITH CONVECTION EXPECTED AFTER
THE END OF THE FORECAST PERIOD.
EXTENDED OUTLOOK...EARLY MORNING FOG POSSIBLE DURING THE EXTENDED
PERIOD. INCREASING CHANCES FOR SHOWERS/T-STORMS SATURDAY THROUGH
MONDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 10 AM THURSDAY...WEAK SFC PRESSURE PATTERN AND GRADIENT TODAY
TO EVOLVE INTO MORE OF A SFC BERMUDA HIGH REGIME TONIGHT AND INTO
THE SHORT TERM. THE SFC RIDGING WILL EXTEND WESTWARD FROM THE SFC
HIGH WELL OFFSHORE...TO THE SE U.S. COAST TONIGHT. THE SFC RIDGE
AXIS TO REMAIN SOUTH OF THE ILM CWA. SOMEWHAT VARIABLE WIND
DIRECTIONS TODAY...WITH A LACK OF A SFC PG YIELDING LESS THAN 10 KT
FOR SPEEDS. THE EXCEPTION WILL BE ESPECIALLY NEAR SHORE WHERE THE
SEA BREEZE CIRCULATION WILL BE THE PRIMARY EMPHASIS FOR WIND DIR AND
SPEEDS FROM MIDDAY THROUGH EARLY THIS EVENING. FOR THE OVERNIGHT
PERIOD...SSW-SW WIND WILL BECOME MORE DOMINANT WITH THE SFC PG
YIELDING A RATHER SOLID 10-15 KT WIND SPEED. SIGNIFICANT SEAS WILL
RANGE BETWEEN 2 TO 3 FEET THROUGH THE FORECAST PERIOD...WITH AVERAGE
PERIODS BETWEEN 5 AND 6 SECONDS.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 330 AM THURSDAY...PIEDMONT TROUGH OVER INLAND CAROLINAS WILL
COMBINE WITH BERMUDA HIGH EXTENDING INTO THE WATERS FROM THE EAST
TO PRODUCE SOUTHERLY WINDS THROUGH THE PERIOD. THE WINDS INITIALLY
WILL BE 10 TO 15 KTS ON FRI WITH SEAS HOLDING AROUND 3 FT OR LESS.
GRADIENT WILL TIGHTEN AND WINDS WILL VEER TO THE SOUTHWEST AS COLD
FRONT PUSHES SOUTHWEST TOWARD THE CAROLINAS THROUGH THE WEEKEND.
EXPECT WINDS TO INCREASE UP TO 15 TO 20 KTS INTO SATURDAY. THIS
PERSISTENT SOUTHERLY FLOW WILL PUSH SEAS UP TO 3 TO 5 FT MOST
WATERS. THE STRENGTH OF THE WINDS WILL VARY DEPENDING ON HOW FAR
SOUTH AND EAST THE FRONT MAKES IT. LATEST RUNS HOLDING BACK ON
SOUTHWARD PROGRESSION OF COLD FRONT AND THEREFORE MAY NOT SEE THE
WINDS INCREASE AS MUCH AS PREVIOUSLY FORECAST. THIS WILL KEEP SEAS
SLIGHTLY LOWER HOLDING BELOW SCA THRESHOLDS IF FRONT HOLDS TO THE
NORTHWEST. WNA SHOWS STEADY INCREASE IN SEAS FRI EVENING THROUGH
SAT EVENING WITH SEAS PEAKING AROUND 5 TO 6 FT IN OUTER WATERS BY
SAT EVENING.
LONG TERM /SUNDAY THROUGH MONDAY/...
AS OF 330 AM THURSDAY...COLD FRONT MAY LINGER INLAND AND WEAKEN
THROUGH THE PERIOD. THEREFORE TIGHTENED GRADIENT FLOW BETWEEN
BERMUDA HIGH TO THE EAST AND FRONT TO THE WEST WILL RELAX THROUGH
MONDAY AS FRONT WEAKENS. EXPECT WINDS INITIALLY UP TO 15 TO 20 KTS
DECREASING DOWN CLOSER TO 15 KTS OR LESS BY MONDAY. WINDS MAY VEER
SLIGHTLY MORE WESTERLY SUN NIGHT INTO MON DEPENDING ON HOW CLOSE
THE FRONT MAKES IT. PERSISTENT SOUTHERLY FLOW WILL KEEP SEAS 3 TO
5 FT THROUGH MOST OF THE PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DCH/8
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...DL/8
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1000 AM EDT THU JUL 18 2013
.SYNOPSIS...
A WEAK TROUGH OF LOW PRESSURE WILL RESIDE ACROSS THE CAROLINA
INTERIOR INTO THE WEEKEND...WHILE BERMUDA HIGH PRESSURE NUDGES
INTO THE REGION FROM THE WESTERN ATLANTIC. A SLOW MOVING COLD FRONT
WILL STALL ACROSS THE AREA EARLY NEXT WEEK...INCREASING THE CHANCE
OF SHOWERS AND STORMS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 10 AM THURSDAY...CLOCKWISE TURNING OF THE ATMOSPHERE AND
DRIER AIR HAS WORKED INTO THE FORECAST AREA IN THE LAST 12 HOURS
AS AN UPPER RIDGE CONTINUES TO NUDGE EASTWARD. PRECIPITABLE WATER
VALUES HAVE DECREASED OVER A HALF INCH SINCE THIS TIME YESTERDAY
AND SUBSIDENT DOWNWARD MOTION PREVAILS CURRENTLY. THUNDERSTORMS
TO BE CONSIDERABLY MORE HINDERED TODAY...WITH MUCH LESS COVERAGE
AND INTENSITY ANTICIPATED. SEVERAL OF OUR MORE USEFUL NEAR TERM
MODELS SUCH AS THE 3KM HRRR AND 4KM NSSL WRF PAINT SIMILAR OUTCOMES
TODAY...GENERATING ISOLATED TO SCATTERED CONVECTION BETWEEN 2PM AND
3PM INLAND FROM THE COAST...PEAKING IN INTENSITY IN THE LATE AFTN
THEN WEAKENING RAPIDLY WITH DIMINISHED SURFACE HEATING INTO EARLY
EVENING. THIS APPEARS REASONABLE GIVEN THE LACKLUSTER INGREDIENTS
IN PLACE. VAPOR ANALYSIS SHOWS A LOCALLY HIGHER SLUG OF COLUMN
MOISTURE BEING GUIDED INTO COASTAL SOUTH CAROLINA AND THIS MAY
ALLOW MORE ACTIVITY LATER TODAY ACROSS OUR VERY SOUTHERN TIER.
NO MAJOR CHANGES PLANNED TO THE ONGOING FORECAST...AND BECAUSE
OF SLIGHTLY LOWER SFC DEWPOINTS TODAY...HEAT INDICES SHOULD HOLD
MOSTLY BELOW 100...HIGHEST INLAND ASSOCIATED WITH A STRONGER
THERMAL AXIS ALONG THE SANDHILLS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 330 AM THURSDAY...ELONGATED RIDGE IN THE MID TO UPPER
LEVELS EXTENDING FROM THE CAROLINAS ACROSS THE TENNESSEE VALLEY
INTO THE DESERT SOUTHWEST WILL WEAKEN OVER THE EAST THROUGH THE
PERIOD AS TROUGH BEGINS TO DIG DOWN FROM CANADA OVER THE WEEKEND.
BERMUDA RIDGE WILL EXTEND WESTWARD INTO THE CAROLINAS FROM THE
SURFACE UP THROUGH THE LOWER LEVELS OF THE ATMOSPHERE. AT THE SAME
TIME THE PIEDMONT TROUGH REMAINS PRONOUNCED INLAND. THIS WILL
PRODUCE A TIGHTENED GRADIENT FLOW OUT OF THE SOUTH TO SOUTHWEST
FRI INTO SATURDAY. THERE SHOULD BE ENOUGH SUBSIDENCE AND DRY AIR
THROUGH THE MID LEVELS TO HELP SUPPRESS ANY WIDESPREAD CONVECTION
ACROSS THE AREA FRI INTO THE FIRST HALF OF THE WEEKEND. AS THE
RIDGE SHIFTS FARTHER SOUTH THROUGH THE MID TO UPPER LEVELS THE
FLOW ALOFT WILL BEGIN TO SHIFT FROM EASTERLY ON FRI TO NORTH
NORTHWEST FRI NIGHT INTO SATURDAY AND EVENTUALLY WESTERLY BY SAT
NIGHT. THIS WILL ALLOW INCREASING MOISTURE TO ADVECT IN BY THE END
OF THE PERIOD AND WILL ALSO STEER CLOUDS AND SHWRS/TSTMS THAT
DEVELOP INLAND TOWARD THE COAST LATE SATURDAY. THE SOUTHWEST
COMPONENT OF THE FLOW IN THE LOW LEVELS WILL KEEP SEA BREEZE FROM
DRIVING TOO FAR INLAND BY SATURDAY. THIS WILL INCREASE CHC OF
SHOWERS CLOSER TO THE COAST ON SATURDAY BUT OVERALL EXPECT MORE
LIMITED SHWR ACTIVITY THROUGH MUCH OF THE PERIOD. TEMPS WILL
REMAIN VERY WARM TYPICAL OF MID SUMMER WITH READINGS AROUND 90
DURING THE DAY AND LOW TO MID 70S AT NIGHT MOST PLACES.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 330 AM THURSDAY...MORE ACTIVE WEATHER EXPECTED EARLY TO MID
WEEK NEXT WEEK. MID TO UPPER TROUGH WILL CONTINUE TO PUSH A COLD
FRONT TOWARD THE CAROLINAS THROUGH EARLY NEXT WEEK. INCREASING
INSTABILITY AND MOISTURE AHEAD OF THIS FRONT WILL COMBINE WITH
BETTER UPPER LEVEL DYNAMICS TO PRODUCE MORE WIDESPREAD SHWR/TSTMS
ACTIVITY THROUGH THE PERIOD. STILL SOMEWHAT UNCERTAIN AS TO HOW
FAR THE FRONT WILL MAKE IT BUT LATEST GFS SHOWS THIS BOUNDARY
REACHING INTO NORTH CAROLINA BY EARLY MONDAY AND POSSIBLY
REMAINING OVER THE CAROLINAS THROUGH MID WEEK. DECENT MID TO UPPER
LEVEL SHORTWAVE ENERGY WILL RIDE THROUGH LONGER WAVE TROUGH
REACHING DOWN FROM CANADA THROUGH EARLY TO MID WEEK. THIS WILL
ENHANCE SHWR/TSTM ACTIVITY EACH DAY. INCREASED CLOUDINESS AND
CONVECTION WILL LEAD TO FLUCTUATIONS IN TEMPS THROUGH THE DAY BUT
OVERALL EXPECT READINGS RIGHT NEAR OR ABOVE NORMAL...AROUND 90
DURING THE DAY AND HOLDING IN THE LOWER TO MID 70S OVERNIGHT.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
AS OF 14Z...DENSE FOG IN SPOTS WILL MIX OUT BY 13Z OR SO. LARGE
THUNDERSTORM COMPLEX MOVED OUT OF THE REGION LAST NIGHT. THE
ATMOSPHERE IS PRETTY WORKED OVER...BUT THE SAME BOUNDARY THAT FIRED
THE CONVECTION YESTERDAY IS STILL AROUND...VISIBLE ON WATER VAPOR.
WE SHOULD SEE SOME ISOLATED/SCATTERED ACTIVITY THIS
AFTERNOON...FOCUSED MAINLY AT THE RESULTANT AND ALONG THE PIEDMONT
TROUGH. LIGHT AND VARIABLE WINDS THIS MORNING WILL GIVE WAY TO A
MAINLY SOUTHERLY COMPONENT BY MIDDAY.
EXTENDED OUTLOOK...EARLY MORNING FOG POSSIBLE DURING THE EXTENDED
PERIOD. INCREASING CHANCES FOR SHOWERS/T-STORMS SATURDAY THROUGH
MONDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 10 AM THURSDAY...WEAK SFC PRESSURE PATTERN AND GRADIENT TODAY
TO EVOLVE INTO MORE OF A SFC BERMUDA HIGH REGIME TONIGHT AND INTO
THE SHORT TERM. THE SFC RIDGING WILL EXTEND WESTWARD FROM THE SFC
HIGH WELL OFFSHORE...TO THE SE U.S. COAST TONIGHT. THE SFC RIDGE
AXIS TO REMAIN SOUTH OF THE ILM CWA. SOMEWHAT VARIABLE WIND
DIRECTIONS TODAY...WITH A LACK OF A SFC PG YIELDING LESS THAN 10 KT
FOR SPEEDS. THE EXCEPTION WILL BE ESPECIALLY NEAR SHORE WHERE THE
SEA BREEZE CIRCULATION WILL BE THE PRIMARY EMPHASIS FOR WIND DIR AND
SPEEDS FROM MIDDAY THROUGH EARLY THIS EVENING. FOR THE OVERNIGHT
PERIOD...SSW-SW WIND WILL BECOME MORE DOMINANT WITH THE SFC PG
YIELDING A RATHER SOLID 10-15 KT WIND SPEED. SIGNIFICANT SEAS WILL
RANGE BETWEEN 2 TO 3 FEET THROUGH THE FORECAST PERIOD...WITH AVERAGE
PERIODS BETWEEN 5 AND 6 SECONDS.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 330 AM THURSDAY...PIEDMONT TROUGH OVER INLAND CAROLINAS WILL
COMBINE WITH BERMUDA HIGH EXTENDING INTO THE WATERS FROM THE EAST
TO PRODUCE SOUTHERLY WINDS THROUGH THE PERIOD. THE WINDS INITIALLY
WILL BE 10 TO 15 KTS ON FRI WITH SEAS HOLDING AROUND 3 FT OR LESS.
GRADIENT WILL TIGHTEN AND WINDS WILL VEER TO THE SOUTHWEST AS COLD
FRONT PUSHES SOUTHWEST TOWARD THE CAROLINAS THROUGH THE WEEKEND.
EXPECT WINDS TO INCREASE UP TO 15 TO 20 KTS INTO SATURDAY. THIS
PERSISTENT SOUTHERLY FLOW WILL PUSH SEAS UP TO 3 TO 5 FT MOST
WATERS. THE STRENGTH OF THE WINDS WILL VARY DEPENDING ON HOW FAR
SOUTH AND EAST THE FRONT MAKES IT. LATEST RUNS HOLDING BACK ON
SOUTHWARD PROGRESSION OF COLD FRONT AND THEREFORE MAY NOT SEE THE
WINDS INCREASE AS MUCH AS PREVIOUSLY FORECAST. THIS WILL KEEP SEAS
SLIGHTLY LOWER HOLDING BELOW SCA THRESHOLDS IF FRONT HOLDS TO THE
NORTHWEST. WNA SHOWS STEADY INCREASE IN SEAS FRI EVENING THROUGH
SAT EVENING WITH SEAS PEAKING AROUND 5 TO 6 FT IN OUTER WATERS BY
SAT EVENING.
LONG TERM /SUNDAY THROUGH MONDAY/...
AS OF 330 AM THURSDAY...COLD FRONT MAY LINGER INLAND AND WEAKEN
THROUGH THE PERIOD. THEREFORE TIGHTENED GRADIENT FLOW BETWEEN
BERMUDA HIGH TO THE EAST AND FRONT TO THE WEST WILL RELAX THROUGH
MONDAY AS FRONT WEAKENS. EXPECT WINDS INITIALLY UP TO 15 TO 20 KTS
DECREASING DOWN CLOSER TO 15 KTS OR LESS BY MONDAY. WINDS MAY VEER
SLIGHTLY MORE WESTERLY SUN NIGHT INTO MON DEPENDING ON HOW CLOSE
THE FRONT MAKES IT. PERSISTENT SOUTHERLY FLOW WILL KEEP SEAS 3 TO
5 FT THROUGH MOST OF THE PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DCH/MJC
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...DL
AREA FORECAST DISCUSSION
NWS BISMARCK ND
903 PM CDT FRI JUL 19 2013
.UPDATE...
ISSUED AT 903 PM CDT FRI JUL 19 2013
LATEST RADAR IMAGERY CONTINUES TO SHOW SCATTERED THUNDERSTORMS
STRETCHED FROM NORTHWEST TO SOUTHEAST ALONG AND AHEAD OF A COLD
FRONT. BASED ON THE 3HR PRESSURE CHANGE...THIS FRONT WOULD ROUGHLY
FOLLOW ALONG A WATFORD CITY TO HAZEN...AND INTO STEELE AND
EDGELEY. SEVERAL OUTFLOWS EVIDENT WHICH MAY PRODUCE MORE
CONVECTION ACROSS SOUTH CENTRAL NORTH DAKOTA THROUGH THE EVENING
AND OVERNIGHT...WHICH IS WHAT THE HRRR INDICATES AS WELL. SEVERE
THREAT LOOKS TO REMAIN ISOLATED BUT WILL NEED TO CLOSELY MONITOR.
UPDATE ISSUED AT 659 PM CDT FRI JUL 19 2013
LATEST 3HR PRESSURE CHANGE SHOWS A COLD FRONT NEAR/ALONG OUR
NORTHERN BORDER SLOWLY PUSHING SOUTH. SCATTERED THUNDERSTORMS
CONTINUE TO DEVELOP ALONG AND AHEAD OF THE FRONT AS THEY MOVE
SOUTHEAST WITH TIME. LATEST HRRR/HIGH RESOLUTION RAPID REFRESH MODEL
SHOWS FIRST AREA OF SHOWERS AND THUNDERSTORMS IN NORTH CENTRAL
NORTH DAKOTA MOVING INTO THE JAMES RIVER VALLEY THROUGH 05Z
SATURDAY. THE OTHER ITEM OF INTEREST ARE THE SHOWERS AND
THUNDERSTORMS IN NORTHEAST MONTANA WHICH ARE FORECAST TO REACH
KBIS BY AROUND 07Z. EXPECTING ISOLATED SEVERE THUNDERSTORMS TO
CONTINUE THROUGH THE EVENING.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 306 PM CDT FRI JUL 19 2013
SHORT TERM CONCERNS INVOLVE THUNDERSTORMS NORTH CENTRAL ASSOCIATED
WITH A CANADIAN COLD FRONT SLIDING SOUTH ACROSS THE REGION. CAPE
VALUES SHOW POTENTIAL FOR STRONG THUNDERSTORMS BUT MID LEVEL LAPSE
RATES AROUND 5 TO 6 DEGREES SHOULD LIMIT THE SEVERE POTENTIAL.
HOWEVER THE POTENTIAL FOR SOME HAIL AND GUSTY WINDS EXISTS THIS
EVENING. EXPECT SOME DIURNAL MINIMUM TONIGHT FOR THE STORMS...AND
SCATTERED THUNDERSTORMS ALONG THE FRONTAL ZONE SOUTH CENTRAL AND
WEST SATURDAY.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 306 PM CDT FRI JUL 19 2013
H5 PATTERN PER GFS/ECMWF CONTINUES WITH MOSTLY A NORTHWEST FLOW
ALOFT THROUGH THE PERIOD. PERIODIC UPPER DISTURBANCES IN COMBINATION
WITH INSTABILITY AND DYNAMICAL PARAMETERS IN PLACE WILL ALLOW FOR A
CHANCE OF SHOWERS AND/OR THUNDERSTORMS ALMOST EVERYDAY...WITH THE
EXCEPTION OF MONDAY...WHERE A DRY DAY IS FORECAST.
FOR SATURDAY NIGHT AND SUNDAY...MAIN HIGHLIGHT HERE IS A MORE
SIGNIFICANT SHORTWAVE MOVING THROUGH SOUTHERN SASKATCHEWAN SUNDAY
MORNING AND INTO SOUTHERN MANITOBA BY SUNDAY AFTERNOON. A SURFACE
COLD FRONT WILL BE ASSOCIATED WITH THE SHORTWAVE ALOFT AS IT SLIDES
FROM WEST TO EAST SUNDAY AFTERNOON AND EVENING. BEST FORCING/OMEGA
RESIDES IN THE NORTH CENTRAL SUNDAY AFTERNOON THEN SHIFTS INTO EAST
CENTRAL NORTH DAKOTA SUNDAY EVENING. VERTICAL MOTION IS ENHANCED BY
THE LEFT EXIT REGION OF A 60KT H3 JET STREAK ACROSS THE
AFOREMENTIONED AREA. GFS SHOWS ENOUGH CAPE AND 0-6KM SHEAR OF 45KT
TO 50KT FOR ORGANIZED STORMS WHICH WILL FAVOR SOME SEVERE
THUNDERSTORMS NORTH CENTRAL THROUGH EAST CENTRAL SUNDAY AFTERNOON
THROUGH SUNDAY EVENING. SPC DAY 3 OUTLOOK HAS THE ABOVE AREA IN A
SEE TEXT WITH HAIL AND WIND AS THE PRIMARY THREATS. H85 TEMPS RISE
TO BETWEEN +26C TO +28C IN THE WARM SECTOR SUNDAY AFTERNOON WEST PER
NAM/GFS...HIGHS WILL TOP OUT AROUND 90 OR LOWER 90S. HAVE INCREASED
TEMPS TO REFLECT THIS...HOWEVER DID NOT GO AS WARM AS THE NAM MOS
WANTED DUE TO SOME CLOUD COVER HOLDING TEMPS BACK IN THE MORNING TO
EARLY AFTERNOON. SHOULD BE A QUICK RISE THEREAFTER.
MONDAY...BEHIND THE COLD FRONT...GFS SOUNDINGS SHOW LOW LEVEL COLD
AIR ADVECTION WITH NEUTRAL ADVECTION ALOFT WILL YIELD A COOLER/DRIER
DAY WITH HIGHS IN THE UPPER 70S NORTH TO UPPER 80S SOUTH.
FOR TUESDAY THROUGH FRIDAY...ADDITIONAL SHORTWAVES EMBEDDED IN THE
NORTHWEST FLOW WILL INTERACT WITH THE AFTERNOON/EVENING INSTABILITY
AND SOME JET FORCING AT TIMES TO INITIATE A CHANCE OF
SHOWERS/THUNDERSTORMS.
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 659 PM CDT FRI JUL 19 2013
A COLD FRONT APPROACHING KMOT AND KISN MOVING SOUTH WITH TIME IS
PRODUCING SCATTERED THUNDERSTORMS OVER NORTH CENTRAL NORTH DAKOTA.
WILL BEGIN WITH PREDOMINANT THUNDERSTORMS OVER KMOT AT 00Z SATURDAY
WITH A GRADUAL SOUTHWARD MOVEMENT OVERNIGHT. STILL EXPECTING VFR
CIGS/VSBYS OUTSIDE OF THE THUNDERSTORMS WITH POSSIBLE TEMPO MVFR
CIGS/VSBYS WITH THE STRONGER THUNDERSTORMS.
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
$$
UPDATE...KS
SHORT TERM...WAA
LONG TERM...KS
AVIATION...KS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
250 PM CDT THU JUL 18 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 250 PM CDT THU JUL 18 2013
SEVERE POTENTIAL THIS EVENING WILL BE THE MAIN CONCERN. HEAT
ADVISORY CONDITIONS ACROSS THE SOUTHERN FA WILL CONTINUE INTO THE
EARLY EVENING HOURS. THE MAIN SEVERE RISK AREA WILL BE ALONG THE
WARM FRONT FROM JUST EAST OF GRAND FORKS INTO BEMIDJI...AND
LOCATIONS 50 MILES NORTH AND SOUTH OF THIS LINE. SPC SUPERCELL
COMPOSITE AND SIGNIFICANT TORNADO PARAMETERS INDICATE THIS AREA
WITH THE GREATEST POTENTIAL. 19Z LAPS ANALYSIS STILL INDICATES A
STRONG CAP (MLCIN AOA 40 J/KG)...AND NOT SURE HOW WIDESPREAD
INITIATION WILL BE. HRRR HAS BEEN CONSISTENT WITH DEVELOPING
STORMS...AND WILL CONTINUE TO FOLLOW ITS COVERAGE AND INITIATION
TIMES. ANTICIPATE SUPERCELL STORMS CAPABLE OF ALL MODES OF SEVERE
WEATHER. THERE IS ANOTHER AREA OF CONCERN ACROSS THE NW FA AS THE
UPPER WAVE APPROACHES THIS EVENING. AN AREA OF STORMS HAS
DEVELOPED WELL TO THE NW IN SASKATCHEWAN (JUST AHEAD OF THE UPPER
WAVE)...AND INSTABILITY SHOULD INCREASE JUST AHEAD OF THIS
COMPLEX. THIS COMPLEX MAY STILL BE SEVERE AS IT MOVES INTO THE NW
FA...AND QUICKLY WEAKEN BY MIDNIGHT.
FRIDAY-FRIDAY NIGHT...ANOTHER COLD FRONT WILL MOVE INTO THE REGION
ON FRIDAY. INSTABILITY WILL BE WEAK...BUT SHOULD BE ENOUGH FOR
ISOLD SHOWERS AND POSSIBLY THUNDER FRIDAY AFTERNOON. SFC HIGH
PRESSURE WILL BEGIN WORKING INTO THE REGION FROM THE NE FRIDAY
NIGHT...AND MIN TEMPS BY SATURDAY MORNING SHOULD BE INTO THE 40S
ACROSS NE MN (WARMER TO THE WEST AND SOUTH).
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 250 PM CDT THU JUL 18 2013
SATURDAY-SUNDAY...MODELS AGREE WITH NORTHWEST FLOW ALOFT AND
SURFACE RIDGING ACROSS MUCH OF THE FA. THE SURFACE RIDGE GRADUALLY
SHIFTS BACK TO THE EAST BY SUNDAY. THUNDER CHANCES WILL BE ON THE
WESTERN EDGE OF THE FA ON SATURDAY...AND SHIFT TO THE EAST BY
SUNDAY. FORCING AND INSTABILITY WILL BE WEAK...SO EXPECT ONLY
ISOLD TO SCATTERED ACTIVITY. TEMPERATURES WILL BE BELOW NORMAL
VALUES AS A RELATIVELY COLDER AIRMASS WILL BE ACROSS THE REGION.
SUNDAY NIGHT-THURSDAY...LONG TERM MODELS ARE IN POOR AGREEMENT.
IN GENERAL...ECMWF TRACK OF SFC LOWS TRANSITING SOUTHERN CANADA
NEXT WEEK ARE MUCH FURTHER NORTH THAN THE GFS...WHICH BRINGS THEM
ACROSS NORTHERN TIER OF CONUS. ECMWF ALSO CONTINUES TO PRODUCE A
LOT OF QPF...WHICH SEEMS UNREALISTIC. THEY DO AGREE SOMEWHAT ON A
NW FLOW UPPER AIR PATTERN BUT EVEN THAT DIVERGES BY DAY 6. THUS
LOW POPS IN CONSALL IS A RESULT OF ECMWF BLENDED INTO THE
SOLUTION. CONFIDENCE IS LOW BEYOND DAY 4 (NIGHT). BEST CHANCE
APPEARS TO BE SUN NIGHT INTO MON MORNING...WHEN AN UPPER WAVE
MOVES ACROSS THE AREA. BEST CHANCES WILL BE ACROSS THE NORTHEAST
AND DO HAVE A FAIR DEGREE OF CONFIDENCE FOR 40S POPS ACROSS THE
NORTH. GFS WOULD THEN GIVE US DRY WEATHER MON NIGHT AND I HAVE
REMOVED CHANCE POPS FOR THIS PERIOD. GFS THEN BRINGS ANOTHER SFC
LOW INTO NORTHERN TIER TUE NIGHT...FOR ANOTHER CHANCE OF
SHOWERS/TSTMS ACROSS THE NORTH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1240 PM CDT THU JUL 18 2013
WARM FRONT CURRENTLY OVER NORTH CENTRAL VALLEY WILL BEGIN TO DROP
SOUTHEAST THIS AFTN...AND WILL ADD VCTS TO BJI AND FAR FOR BRIEF
PERIOD THIS AFTN. 4KM WRF SHOWS CONVECTION AS A NARROW BAND AND HAS
BEEN PERFORMING WELL...BUT IF MID LEVELS DESTABILIZE COULD EASILY
SEE SOME TSTMS IN VCNTY OF OTHER TAF SITES. SECONDARY SHOT OF
SHOWERS/TSTMS WILL MOVE ACROSS AREA LATE EVENING INTO THE
OVERNIGHT PERIOD. WILL KEEP MAINLY VCSH AS CONFIDENCE NOT HIGH
ENOUGH YET TO GO PREDOMINANT. DO EXPECT VFR CIGS WITH ANY
ACTIVITY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR NDZ038-039-049-052-
053.
MN...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR MNZ003-027>031-040.
&&
$$
SHORT TERM...TG
LONG TERM...TG/SPEICHER
AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS BISMARCK ND
101 PM CDT THU JUL 18 2013
.UPDATE...
ISSUED AT 101 PM CDT THU JUL 18 2013
HEAT INDICES APPROACHING 100F OVER THE JAMES RIVER BASIN IS STILL
FORECAST FOR THIS AFTERNOON. AS A RESULT...WILL MAINTAIN THE HEAT
ADVISORY FOR THE JAMES RIVER BASIN THIS AFTERNOON.
MSAS ANALYZED A SURFACE CYCLONE CENTERED OVER GRAND FORKS AT 17Z.
LAPS ANALYZED INCREASING SURFACE-BASED CAPE (AROUND 2500 J/KG) IN
THE WARM SECTOR OF THE SURFACE LOW ACROSS SOUTH CENTRAL AND
SOUTHEASTERN NORTH DAKOTA. THE 16Z HRRR-3KM CONTINUES TO DEVELOP
SCATTERED THUNDERSTORMS ACROSS THE JAMES RIVER VALLEY BETWEEN 21Z-
00Z THIS AFTERNOON. HOWEVER...COVERAGE AND INTENSITY IS LESS THAN
PREVIOUS RUNS WOULD SUGGEST DUE TO THE CAP. STILL CANNOT TOTALLY
RULE OUT THE POSSIBILITY OF A SEVERE STORM THIS AFTERNOON. WILL
MAINTAIN MENTION IN THE HWO FOR NOW AS A RESULT.
SHIFTING FOCUS NORTH...A LINE OF CONVECTION IS ALREADY FIRING OVER
SOUTH-CENTRAL SASKATCHEWAN. BASED ON THE CURRENT TRAJECTORY...THIS
ACTIVITY WILL BE NEAR THE ND/CANADIAN BORDER BETWEEN 23Z-00Z.
STILL THINK NORTH CENTRAL NORTH DAKOTA COULD SEE SEVERE STORMS
BETWEEN 00Z-03Z TONIGHT. WILL CONTINUE TO MENTION THIS POSSIBILITY
IN THE HWO.
UPDATE ISSUED AT 1027 AM CDT THU JUL 18 2013
SOUTHWESTERLY FLOW ACROSS SOUTH CENTRAL AND SOUTHEASTERN NORTH
DAKOTA IS STILL FORECAST TO GENERATE HEAT INDICES APPROACHING 100F
OVER THE JAMES RIVER BASIN THIS AFTERNOON. AS A RESULT...WILL
MAINTAIN THE HEAT ADVISORY FOR THE JAMES RIVER BASIN THIS
AFTERNOON.
MSAS ANALYSIS SHOWS A SURFACE COLD FRONT EXTENDING FROM AROUND
MAYVILLE TO STEELE TO FORT YATES. LAPS ANALYSIS INDICATES
INCREASING SURFACE-BASED CAPE AROUND 1500 J/KG AHEAD OF THE COLD
FRONT OVER THE JAMES RIVER VALLEY. AS THE FRONT PUSHES ACROSS
NORTH DAKOTA TODAY...SHORT RANGE HIGH RES MODEL GUIDANCE PROGS
SCATTERED CONVECTION TO BEGIN OVER THE JAMES RIVER BASIN AROUND
20Z AND PUSH INTO THE SOUTHERN RED RIVER VALLEY THROUGH 00Z.
MARGINAL DEEP LAYER SHEAR IS THE ONLY INGREDIENT LIMITING
CONFIDENCE IN STORMS BECOMING SEVERE. AS A RESULT...WILL KEEP
SEVERE MENTION OUT OF THE ZONES...BUT KEEP IT IN THE HWO.
FARTHER NORTH...AN UPPER LEVEL WAVE IS EXPECTED TO TRIGGER
THUNDERSTORMS OVER THE SOUTHERN CANADIAN PRAIRIES LATER THIS
AFTERNOON. THE 3KM HRRR AND 00Z WRF PROG THIS ACTIVITY TO
PROPAGATE INTO NORTH CENTRAL NORTH DAKOTA AFTER 00Z THIS EVENING.
GIVEN THE STRONG UPPER FORCING AND POSSIBLE MCS
MAINTENANCE/PROPAGATION...NORTH CENTRAL NORTH DAKOTA COULD SEE
SEVERE STORMS BETWEEN 00Z-03Z TONIGHT. WILL CONTINUE TO MENTION
THIS POSSIBILITY IN THE HWO.
UPDATE ISSUED AT 648 AM CDT THU JUL 18 2013
ELEVATED CONVECTION THAT DEVELOPED OVERNIGHT IN FAR NORTHWEST
NORTH DAKOTA HAS MOVED EAST OUT OF THE FORECAST AREA. THEREFORE WE
HAVE REMOVED THE POPS ACROSS THE FAR NORTH CENTRAL FOR THIS
MORNING. OTHERWISE MINIMAL UPDATES THIS MORNING. DID REDUCE CLOUD
COVER A BIT ACROSS WITH THE EXITING PRECIPITATION AND RAISED IT A
BIT OVER THE SOUTHWEST AS MID LEVEL CLOUDS MOVE INTO THIS AREA
AHEAD OF A MID LEVEL SHORTWAVE. AS THE SHORTWAVE MOVES ACROSS THE
SOUTHERN PRAIRIE PROVINCES OF CANADA TODAY CONVECTION IS EXPECTED
TO DEVELOP ACROSS THE NORTHERN TIER COUNTIES LATE THIS AFTERNOON
AND POSSIBLY ALONG THE SURFACE TROUGH IN THE SOUTH CENTRAL BY
EARLY TO MID AFTERNOON. CURRENT FORECAST HAS THIS COVERED. NO
CHANGES TO THE CURRENT HEAT ADVISORY OVER THE JAMES RIVER VALLEY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 313 AM CDT THU JUL 18 2013
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE CHANCES FOR
THUNDERSTORMS NORTH AND SOUTH AND VERY WARM AND HUMID CONDITIONS
SOUTH CENTRAL AND SOUTHEAST.
CURRENTLY...ZONAL FLOW ALOFT WITH AN EMBEDDED S/WV MOVING EAST
ALONG THE INTERNATIONAL BORDER. ONGOING EARLY MORNING CONVECTION
FAR NORTH WILL START TO PUSH OFF TO THE NORTH AND EAST NOW THROUGH
12Z AS THE MID LEVEL ENERGY PUSHES EAST AND THE INFLUENCE OF A
NOCTURNAL LOW LEVEL JET DECREASES WITH TIME.
FOR THE REST OF THIS MORNING...AFTER THE EARLY MORNING CONVECTION
NORTH...WE LOOK TO BE MAINLY DRY UNTIL MID TO LATE MORNING WHEN
MODELS SUGGEST PRECIPITATION DEVELOPING OVER SOUTHEASTERN MONTANA
AND PERHAPS AS FAR EAST AS FAR SOUTHWEST NORTH DAKOTA AS AN
UPSLOPE FLOW MATERIALIZES.
SFC TROUGH AXIS THURSDAY AFTERNOON WILL BE ORIENTATED FROM THE
BLACK HILLS OF SOUTH DAKOTA NORTHEAST INTO THE CENTRAL RED RIVER
VALLEY OF EASTERN NORTH DAKOTA. WHILE MID LEVEL FORCING IS
EXPECTED TO BE WEAK OVER NORTH DAKOTA WITH NO REAL WAVE FEATURED
IN MODELS UNTIL LATER IN THE DAY ACROSS THE NORTH...MAY BE ENOUGH
LOW LEVEL FORCING/CONVERGENCE ALONG THE TROUGH AXIS TO GENERATE
DAYTIME THUNDERSTORMS OVER MY SOUTHERN COUNTIES WITH PLENTY OF
INSTABILITY EXPECTED TO BE IN PLACE.
CHANCES FOR THUNDERSTORMS INCREASE ACROSS THE NORTH AND DEVELOP
EAST AND SLIGHTLY SOUTH MID TO LATE AFTERNOON AS A MID LEVEL S/WV
TROUGH MOVES EAST-SOUTHEAST INTO SOUTHERN SASKATCHEWAN 21-00Z AND
INTO NORTHERN NORTH DAKOTA THURSDAY EVENING. COVERAGE AND CHANCES
FOR THUNDERSTORMS DECREASE AFTER 06Z WITH THE WAVE CONTINUING TO
TRACK SOUTHEAST TOWARDS/INTO WESTERN MINNESOTA. WILL CONTINUE TO
MENTION THE POSSIBILITY OF SEVERE THUNDERSTORMS IN THE HWO.
BESIDES THUNDERSTORM CHANCES TODAY...BOUNDARY LAYER TEMPERATURES
APPROACHING 30C ACROSS THE SOUTH WILL RESULT IN AFTERNOON
TEMPERATURES IN THE 90S ALONG AND SOUTH OF INTERSTATE 94...WITH
THE WARMEST TEMPERATURES FAR SOUTH CENTRAL AND SOUTH EAST WHERE
HIGHS ARE FORECAST TO CLIMB TO OVER 95F. COMBINED WITH SFC
DEWPOINTS 65-70F...HEAT INDICES WILL APPROACH 100F OVER THE JAMES
RIVER BASIN AND REACH INTO THE UPPER 90S FAR SOUTH CENTRAL. WILL
THUS MAINTAIN THE HEAT ADVISORY FOR THE JAMES RIVER BASIN FOR THIS
AFTERNOON WHERE THE HIGHEST HEAT INDEX IS EXPECTED...AND LEAVE
THE FAR SOUTH CENTRAL OUT FOR NOW AS THEY ARE...AT THIS FORECAST
ISSUANCE...EXPECTED TO FALL BELOW HEAT ADVISORY CRITERIA. DRY AIR
IS EXPECTED TO FILTER INTO THE SOUTHWEST RESULTING IN THE HEAT
INDICES THERE TO BE AROUND 90...OR NEAR THE ACTUAL TEMPERATURE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 313 AM CDT THU JUL 18 2013
WE BEGIN THE LONG TERM PERIOD WITH A NORTHWEST UPPER FLOW PATTERN
AND ISOLATED TO SCATTERED THUNDERSTORM ACTIVITY ALONG THE
CONVERGENCE ZONE ASSOCIATED WITH A BACKDOOR COLD FRONT THAT PUSHES
SLOWLY WESTWARD FRIDAY AND SATURDAY. DEEP MOISTURE WILL BE LACKING
BUT THERE SHOULD BE ENOUGH MOISTURE/INSTABILITY ALONG THE BOUNDARY
FOR A FEW SHOWERS/THUNDERSTORMS EACH DAY. TEMPERATURES WILL BE
NOTICEABLY COOLER ACROSS THE SOUTH WITH READINGS FALLING INTO THE
80S AFTER A COUPLE DAYS OF 90 DEGREE HEAT.
THE REMAINDER OF THE EXTENDED PERIOD WILL BRING SEASONABLE
TEMPERATURES WITH PERIODIC THUNDERSTORM CHANCES ASSOCIATED WITH A
SERIES OF SHORTWAVES TRAVELING THROUGH A NORTHWEST FLOW ALOFT. THE
BETTER CHANCES AT THIS TIME APPEAR TO BE SUNDAY NIGHT INTO MONDAY
AND AGAIN TUESDAY NIGHT INTO WEDNESDAY. HOWEVER THIS FAR OUT TIMING
AND PLACEMENT OF INDIVIDUAL WAVES IS DIFFICULT AND A MODEL BLEND WAS
UTILIZED WHICH KEEPS AT LEAST A SLIGHT CHANCE OF CONVECTION THROUGH
THE PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 101 PM CDT THU JUL 18 2013
VFR CONDITIONS WILL PREVAIL OVER WESTERN AND CENTRAL NORTH
DAKOTA. THERE WILL BE A NARROW WINDOW WHERE THUNDERSTORMS COULD
IMPACT KJMS BETWEEN 20Z-22Z...AND IMPACT KMOT BETWEEN 01Z-03Z.
HOWEVER...GIVEN THE LOW CONFIDENCE IN OCCURRENCE...ONLY INDICATED
VCTS AND VFR CONDITIONS IN BOTH THE KMOT AND KJMS TAFS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR NDZ037-047-048-050-
051.
&&
$$
UPDATE...TM
SHORT TERM...NH
LONG TERM...TWH
AVIATION...TM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1027 AM CDT THU JUL 18 2013
.UPDATE...
ISSUED AT 1027 AM CDT THU JUL 18 2013
SOUTHWESTERLY FLOW ACROSS SOUTH CENTRAL AND SOUTHEASTERN NORTH
DAKOTA IS STILL FORECAST TO GENERATE HEAT INDICES APPROACHING 100F
OVER THE JAMES RIVER BASIN THIS AFTERNOON. AS A RESULT...WILL
MAINTAIN THE HEAT ADVISORY FOR THE JAMES RIVER BASIN THIS
AFTERNOON.
MSAS ANALYSIS SHOWS A SURFACE COLD FRONT EXTENDING FROM AROUND
MAYVILLE TO STEELE TO FORT YATES. LAPS ANALYSIS INDICATES
INCREASING SURFACE-BASED CAPE AROUND 1500 J/KG AHEAD OF THE COLD
FRONT OVER THE JAMES RIVER VALLEY. AS THE FRONT PUSHES ACROSS
NORTH DAKOTA TODAY...SHORT RANGE HIGH RES MODEL GUIDANCE PROGS
SCATTERED CONVECTION TO BEGIN OVER THE JAMES RIVER BASIN AROUND
20Z AND PUSH INTO THE SOUTHERN RED RIVER VALLEY THROUGH 00Z.
MARGINAL DEEP LAYER SHEAR IS THE ONLY INGREDIENT LIMITING
CONFIDENCE IN STORMS BECOMING SEVERE. AS A RESULT...WILL KEEP
SEVERE MENTION OUT OF THE ZONES...BUT KEEP IT IN THE HWO.
FARTHER NORTH...AN UPPER LEVEL WAVE IS EXPECTED TO TRIGGER
THUNDERSTORMS OVER THE SOUTHERN CANADIAN PRAIRIES LATER THIS
AFTERNOON. THE 3KM HRRR AND 00Z WRF PROG THIS ACTIVITY TO
PROPAGATE INTO NORTH CENTRAL NORTH DAKOTA AFTER 00Z THIS EVENING.
GIVEN THE STRONG UPPER FORCING AND POSSIBLE MCS
MAINTENANCE/PROPAGATION...NORTH CENTRAL NORTH DAKOTA COULD SEE
SEVERE STORMS BETWEEN 00Z-03Z TONIGHT. WILL CONTINUE TO MENTION
THIS POSSIBILITY IN THE HWO.
UPDATE ISSUED AT 648 AM CDT THU JUL 18 2013
ELEVATED CONVECTION THAT DEVELOPED OVERNIGHT IN FAR NORTHWEST
NORTH DAKOTA HAS MOVED EAST OUT OF THE FORECAST AREA. THEREFORE WE
HAVE REMOVED THE POPS ACROSS THE FAR NORTH CENTRAL FOR THIS
MORNING. OTHERWISE MINIMAL UPDATES THIS MORNING. DID REDUCE CLOUD
COVER A BIT ACROSS WITH THE EXITING PRECIPITATION AND RAISED IT A
BIT OVER THE SOUTHWEST AS MID LEVEL CLOUDS MOVE INTO THIS AREA
AHEAD OF A MID LEVEL SHORTWAVE. AS THE SHORTWAVE MOVES ACROSS THE
SOUTHERN PRAIRIE PROVINCES OF CANADA TODAY CONVECTION IS EXPECTED
TO DEVELOP ACROSS THE NORTHERN TIER COUNTIES LATE THIS AFTERNOON
AND POSSIBLY ALONG THE SURFACE TROUGH IN THE SOUTH CENTRAL BY
EARLY TO MID AFTERNOON. CURRENT FORECAST HAS THIS COVERED. NO
CHANGES TO THE CURRENT HEAT ADVISORY OVER THE JAMES RIVER VALLEY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 313 AM CDT THU JUL 18 2013
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE CHANCES FOR
THUNDERSTORMS NORTH AND SOUTH AND VERY WARM AND HUMID CONDITIONS
SOUTH CENTRAL AND SOUTHEAST.
CURRENTLY...ZONAL FLOW ALOFT WITH AN EMBEDDED S/WV MOVING EAST
ALONG THE INTERNATIONAL BORDER. ONGOING EARLY MORNING CONVECTION
FAR NORTH WILL START TO PUSH OFF TO THE NORTH AND EAST NOW THROUGH
12Z AS THE MID LEVEL ENERGY PUSHES EAST AND THE INFLUENCE OF A
NOCTURNAL LOW LEVEL JET DECREASES WITH TIME.
FOR THE REST OF THIS MORNING...AFTER THE EARLY MORNING CONVECTION
NORTH...WE LOOK TO BE MAINLY DRY UNTIL MID TO LATE MORNING WHEN
MODELS SUGGEST PRECIPITATION DEVELOPING OVER SOUTHEASTERN MONTANA
AND PERHAPS AS FAR EAST AS FAR SOUTHWEST NORTH DAKOTA AS AN
UPSLOPE FLOW MATERIALIZES.
SFC TROUGH AXIS THURSDAY AFTERNOON WILL BE ORIENTATED FROM THE
BLACK HILLS OF SOUTH DAKOTA NORTHEAST INTO THE CENTRAL RED RIVER
VALLEY OF EASTERN NORTH DAKOTA. WHILE MID LEVEL FORCING IS
EXPECTED TO BE WEAK OVER NORTH DAKOTA WITH NO REAL WAVE FEATURED
IN MODELS UNTIL LATER IN THE DAY ACROSS THE NORTH...MAY BE ENOUGH
LOW LEVEL FORCING/CONVERGENCE ALONG THE TROUGH AXIS TO GENERATE
DAYTIME THUNDERSTORMS OVER MY SOUTHERN COUNTIES WITH PLENTY OF
INSTABILITY EXPECTED TO BE IN PLACE.
CHANCES FOR THUNDERSTORMS INCREASE ACROSS THE NORTH AND DEVELOP
EAST AND SLIGHTLY SOUTH MID TO LATE AFTERNOON AS A MID LEVEL S/WV
TROUGH MOVES EAST-SOUTHEAST INTO SOUTHERN SASKATCHEWAN 21-00Z AND
INTO NORTHERN NORTH DAKOTA THURSDAY EVENING. COVERAGE AND CHANCES
FOR THUNDERSTORMS DECREASE AFTER 06Z WITH THE WAVE CONTINUING TO
TRACK SOUTHEAST TOWARDS/INTO WESTERN MINNESOTA. WILL CONTINUE TO
MENTION THE POSSIBILITY OF SEVERE THUNDERSTORMS IN THE HWO.
BESIDES THUNDERSTORM CHANCES TODAY...BOUNDARY LAYER TEMPERATURES
APPROACHING 30C ACROSS THE SOUTH WILL RESULT IN AFTERNOON
TEMPERATURES IN THE 90S ALONG AND SOUTH OF INTERSTATE 94...WITH
THE WARMEST TEMPERATURES FAR SOUTH CENTRAL AND SOUTH EAST WHERE
HIGHS ARE FORECAST TO CLIMB TO OVER 95F. COMBINED WITH SFC
DEWPOINTS 65-70F...HEAT INDICES WILL APPROACH 100F OVER THE JAMES
RIVER BASIN AND REACH INTO THE UPPER 90S FAR SOUTH CENTRAL. WILL
THUS MAINTAIN THE HEAT ADVISORY FOR THE JAMES RIVER BASIN FOR THIS
AFTERNOON WHERE THE HIGHEST HEAT INDEX IS EXPECTED...AND LEAVE
THE FAR SOUTH CENTRAL OUT FOR NOW AS THEY ARE...AT THIS FORECAST
ISSUANCE...EXPECTED TO FALL BELOW HEAT ADVISORY CRITERIA. DRY AIR
IS EXPECTED TO FILTER INTO THE SOUTHWEST RESULTING IN THE HEAT
INDICES THERE TO BE AROUND 90...OR NEAR THE ACTUAL TEMPERATURE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 313 AM CDT THU JUL 18 2013
WE BEGIN THE LONG TERM PERIOD WITH A NORTHWEST UPPER FLOW PATTERN
AND ISOLATED TO SCATTERED THUNDERSTORM ACTIVITY ALONG THE
CONVERGENCE ZONE ASSOCIATED WITH A BACKDOOR COLD FRONT THAT PUSHES
SLOWLY WESTWARD FRIDAY AND SATURDAY. DEEP MOISTURE WILL BE LACKING
BUT THERE SHOULD BE ENOUGH MOISTURE/INSTABILITY ALONG THE BOUNDARY
FOR A FEW SHOWERS/THUNDERSTORMS EACH DAY. TEMPERATURES WILL BE
NOTICEABLY COOLER ACROSS THE SOUTH WITH READINGS FALLING INTO THE
80S AFTER A COUPLE DAYS OF 90 DEGREE HEAT.
THE REMAINDER OF THE EXTENDED PERIOD WILL BRING SEASONABLE
TEMPERATURES WITH PERIODIC THUNDERSTORM CHANCES ASSOCIATED WITH A
SERIES OF SHORTWAVES TRAVELING THROUGH A NORTHWEST FLOW ALOFT. THE
BETTER CHANCES AT THIS TIME APPEAR TO BE SUNDAY NIGHT INTO MONDAY
AND AGAIN TUESDAY NIGHT INTO WEDNESDAY. HOWEVER THIS FAR OUT TIMING
AND PLACEMENT OF INDIVIDUAL WAVES IS DIFFICULT AND A MODEL BLEND WAS
UTILIZED WHICH KEEPS AT LEAST A SLIGHT CHANCE OF CONVECTION THROUGH
THE PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 648 AM CDT THU JUL 18 2013
VFR CONDITIONS ARE EXPECTED THROUGH THE 12Z TAF PERIOD. CHANCES
FOR MORNING THUNDERSTORMS WILL DECREASE 12-15Z NORTH AND WILL
LEAVE OUT ANY MENTION FOR KISN-KMOT. ANOTHER ROUND OF
THUNDERSTORMS WILL DEVELOP SOUTH EARLY TO MID AFTERNOON...AND
ACROSS THE NORTH MID TO LATE AFTERNOON INTO THIS EVENING. WILL
INCLUDE A VCTS/VCSH FOR KMOT AND KJMS WHERE THE BETTER CHANCES ARE
EXPECTED.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR NDZ037-047-048-050-
051.
&&
$$
UPDATE...TM
SHORT TERM...NH
LONG TERM...TWH
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
955 AM CDT THU JUL 18 2013
.UPDATE...
ISSUED AT 955 AM CDT THU JUL 18 2013
SHOWERS AND THUNDERSTORMS ASSOCIATED WITHIN STRONGER 850MB WARM
AIR ADVECTION WILL CONTINUE TO PROPAGATE TO THE EAST THIS
MORNING...EXITING THE FA WITHIN THE NEXT COUPLE HOURS. EXPECT A
BREAK IN ACTIVITY UNTIL SOMETIME LATER THIS AFTERNOON. 14Z LAPS
ANALYSIS INDICATES A VERY STRONG CAP AND THIS WILL NEED TO ERODE
BEFORE ANY REDEVELOPMENT. THUS...LOWERED POPS AND REMOVED WEATHER
TO INDICATE THIS POTENTIAL LULL.
FOR THIS AFTERNOON...THE SURFACE BOUNDARY (LOCATED ALONG A VALLEY
CITY TO GRAND FORKS TO BAUDETTE LINE) WILL MAKE LITTLE MOVEMENT
TO THE EAST UNTIL THIS EVENING WHEN THE MAIN UPPER WAVE FINALLY
BEGINS TO APPROACH NE ND. THIS WILL ALLOW AMPLE HEATING AND
MOISTURE RETURN TO THE EAST OF THIS FEATURE. MOST MODEL GUIDANCE
INDICATES MLCAPE AROUND 3000 J/KG ACROSS WEST CENTRAL MINNESOTA
(OR JUST AHEAD OF THE SURFACE BOUNDARY). DEEP LAYER SHEAR WILL BE
INCREASING INTO THE EVENING HOURS...WHICH SHOULD LEAD TO STRONGER
STORMS. THE MAIN QUESTIONS AT THIS POINT ARE WHEN/IF MLCIN WILL
LOWER ENOUGH FOR INITIATION...AND WHERE EXACTLY WILL THE SFC
BOUNDARY BE LOCATED. 12Z HRRR INDICATES INITIATION 21Z-00Z FROM SE
ND INTO THE BJI AREA...WITH MORE WIDESPREAD ACTIVITY EAST OF THE
VALLEY. FOLLOWED THIS IDEA FOR POPS...AND DID INCLUDE T+ FOR THE
BEMIDJI...DETROIT LAKES...PARK RAPIDS...AND WADENA AREAS (WHICH
THE 09Z SREF INDICATES HAVE THE BEST POTENTIAL FOR SEVERE).
THERE SHOULD BE ADDITIONAL ACTIVITY THIS EVENING AS THE MAIN UPPER
WAVE DROPS THROUGH THE FA. NOT SURE HOW MUCH INSTABILITY WILL BE
LEFT OVER FOR SEVERE POTENTIAL AND WILL MONITOR.
THE HEAT ADVISORY STILL LOOKS GOOD.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 330 AM CDT THU JUL 18 2013
THE MAIN CHALLENGE THIS MORNING WILL BE SEVERE POTENTIAL TODAY
INTO TONIGHT. MODELS ARE IN FAIRLY GOOD AGREEMENT...ALTHOUGH
DIFFER IN REGARDS TO TIMING/PLACEMENT OF SFC LOW THIS AFTERNOON.
THIS WILL BE IMPORTANT TO SEVERE WEATHER THREAT TODAY. THE GFS HAS
BEEN THE MOST CONSISTENT THOUGH SO WILL FOLLOW.
FOR TODAY...THERE WILL BE ONGOING ELEVATED THUNDERSTORMS THIS
MORNING MAINLY IN THE NORTHERN 1/3 OF THE REGION. A FEW STORMS
COULD BE STRONG TO LOCALLY SEVERE WITH PERHAPS SOME LARGE HAIL.
HEAVY RAINFALL IS ALSO EXPECTED NEAR ANY STORM WITH PWATS AROUND
1.8 INCHES. THERE SHOULD BE SOMEWHAT OF A BREAK IN CONVECTION FROM
LATE MORNING INTO EARLY AFTERNOON. EXPECT STORMS TO RAPIDLY
DEVELOP THIS AFTERNOON AT LEAST IN NW MN...WHERE MLCAPES WILL BE
AROUND 3000 J/KG WITH 0-6KM BULK SHEAR AROUND 45KT. THE INITIAL
STORM MODE SHOULD BE SUPERCELLS CAPABLE OF VERY LARGE
HAIL...DAMAGING WINDS AND AN ISOLATED TORNADO IS ALSO POSSIBLE.
THE BEST TORNADO POTENTIAL SHOULD OCCUR ALONG A ROS-PKD LINE AND
POINTS NORTH AND EAST FROM 20Z-00Z. FURTHER SOUTH...EXPECT A HOT
DAY WITH TEMPS INTO THE LOW/MID 90S AND HEAT INDICES NEAR OR
SLIGHTLY OVER 100. WILL ISSUE A HEAT ADVISORY HERE AND MOST OF THE
CONVECTION COULD BE CAPPED HERE WITH WARM TEMPS AT 850MB AROUND
+25C.
FOR TONIGHT...STORMS WILL LINGER WITH A STRONGER SHORTWAVE
DROPPING THROUGH DEVELOPING NW FLOW ALOFT. EXPECT A SEVERE THREAT
OF WIND/HAIL UNTIL AROUND 06Z...BEFORE ACTIVITY MOVES EAST OF THE
REGION.
ON FRIDAY...ANOTHER SHORTWAVE DROPS THROUGH THE REGION WITH
LINGERING INSTABILITY AND COLD AIR ALOFT. THERE SHOULD BE AT LEAST
A FEW SHOWERS AND STORMS POSSIBLE BY AFTERNOON IN MOST AREAS WITH
MUCH COOLER TEMPS.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 330 AM CDT THU JUL 18 2013
FOR SATURDAY...TEMPS WILL COOL INTO THE 70S FOR MOST AREAS AND
NEAR 70 IN THE FAR NORTH. THERE WILL BE A LOW CHANCE FOR A SHOWER
OR STORM IN THE FAR SOUTH MAINLY DURING THE AFTERNOON.
FOR SUNDAY TO WEDNESDAY... MODELS IN FAIR AGREEMENT WITH THE
EXTENDED TIME FRAME FOR THE FIRST HALF OF NEXT WEEK. PREDOMINATE
NW 500MB FLOW IS EXPECTED TO GIVE COOLER THAN MID JULY NORMAL
TEMPS FOR THE PERIOD. MONDAY WILL BE THE EXCEPTION AS WARM HUMID
AIR LIFTS INTO THE AREA AHEAD OF SHORT WAVE ENERGY. THIS WILL ALSO
SET THE STAGE FOR A FAIRLY GOOD CHANCE OF CONVECTION ACROSS THE
AREA. OTHERWISE SLIGHT CHC AND CHC POPS EXISTS IN NW FLOW AS TIMING
OF WEAK SW REMAINS POOR.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 645 AM CDT THU JUL 18 2013
HAVE MENTIONED SOME VCTS THIS MORNING AND AFTERNOON IN THE
NORTH...WITH THE SOUTH LIKELY REMAINING MOSTLY DRY. EASTERLY WINDS
SHOULD SHIFT MORE WESTERLY BY THIS EVENING FROM WEST TO EAST
BEHIND A COLD FRONT. MOSTLY VFR CIGS EXPECTED EXCEPT NEAR SHOWERS
AND STORMS WHERE MVFR CONDITIONS ARE POSSIBLE. THERE IS A PATCH OF
IFR CIGS NEAR DVL...AND EXPECT THIS TO DISSIPATE WITHIN THE NEXT
FEW HOURS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM CDT THIS EVENING
FOR NDZ038-039-049-052-053.
MN...HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM CDT THIS EVENING
FOR MNZ003-027>031-040.
&&
$$
UPDATE...TG
SHORT TERM...DK
LONG TERM...JK/DK
AVIATION...DK
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1147 PM CDT WED JUL 17 2013
.UPDATE...
ISSUED AT 1142 PM CDT WED JUL 17 2013
NO CHANGE IN THINKING SINCE UPDATE ISSUED PRIOR. WILL HAVE SCT
TRW- IN NORTHERN AND NORTHEASTERN HALF OF FCST AREA TONIGHT...WITH
DRY JMS-FAR-FFM SOUTHWARD.
UPDATE ISSUED AT 959 PM CDT WED JUL 17 2013
AS EXPECTED MOST OF THE CONVECTION ALONG THE FRONTAL BOUNDARY HAS
WEAKENED SUBSTANTIALLY SINCE 01Z. WINDS INDICATE THE BOUNDARY HAS
SLIPPED SOUTH OF FARGO-MOORHEAD AT 03Z...WITH WINDS INDICATING
BOUNDARY FROM SOUTH OF BEMIDJI TO NORTH OF DETROIT LAKES THEN JUST
SOUTH OF FARGO THEN BACK SOUTH OF VALLEY CITY-JAMESTOWN TO LOW
WEST OF BISMARCK.
WEAK 850 MB WARM ADVECTION ONGOING CURRENTLY WILL LIKELY CONTINUE
ISOLD SHOWERS NEW FEW HOURS. QUESTION IS OVERNIGHT...RAP13
CONTINUE TO SHOW 25 KT LOW LEVEL JET AND PRETTY STRONG BUT NARROW
850 MB WARM ADVECTION ZONE NEAR HIGHWAY TWO REGION OVERNIGHT INTO
THU MORNING AND HRRR DOES BREAK OUT PRECIP NR 07Z BTWN MOT-BIS-JMS
AND MOVES IT EAST-NORTHEAST....SO WILL CERTAINLY MAINTAIN CHANCE
OF STORMS FOR THE OVERNIGHT NORTH OF THE BOUNDARY. THE SHOWERS
ALONG THE INTL BORDER HAVE WEAKENED CONSIDERABLY BUT STILL A FEW
AROUND.
UPDATE ISSUED AT 658 PM CDT WED JUL 17 2013
WARM FRONTAL BOUNDARY LOCATED JUST SOUTH OF BEMIDJI TO ADA THEN TO
NEAR JAMESTOWN. AS EXPECTED WITH DAYTIME HEATING A CU FIELD FORMED
ALONG THE BOUNDARY AND SOME SMALL TSTMS FORMED IN A SCATTERED
FASHION ALONG IT. STRONGEST CELL ATTM NORTHEAST OF BISMARCK. NOT
TOO MUCH TO KEEP THESE GOING PAST DARK SO THESE WILL DIE OFF. A
LARGER AREA OF MORE GENERAL LIGHT RAIN SPREADING THRU SE SASK INTO
SOUTHERN MANITOBA AND SKIRTING THE ND BORDER THIS EVE AND DID
INCREASE POPS TO HIGH CHC OR LIKELY RIGHT ALONG THE BORDER FOR
THIS RAIN. THIS RAIN ASSOC WITH 500 MB SHORT WAVE SHOWN ON WATER
VAPOR NR THE SK/MB/ND BORDER REGION.
BIGGEST QUESTION IS OVERNIGHT. RAP MODEL DOES HAVE A 25 KT 850 MB
JET AND WARM ADVECTION CENTERED FROM CNTRL ND INTO NORTH CENTRAL
MN IN THAT 08Z-12Z PERIOD AND WOULD EXPECT TO SEE AN INCREASE IN
STORM COVERAGE NEAR THIS REGION (OR NEAR HIGHWAY TWO) LATER
TONIGHT WITH MORE GENERAL SHOWERS FARTHER NORTH. SO DID MAINTAIN
AN INCREASE IN POPS OVERNIGHT NORTH AND EAST AREAS OF THE FCST AREA.
DID REMOVE OR DIMINISH POPS IN THE SOUTH TONIGHT AS DOUBT ANY
PRECIP SOUTH OF I-94 THRU 18Z THU AS THAT AREA IN THE WARM AND
CAPPED AIRMASS AND SOUTH OF ANY LOW LEVEL JET INTERACTIONS.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 256 PM CDT WED JUL 17 2013
CURRENT SATELLITE SHOWS CU BEGINNING TO DEVELOP ALONG STAGNANT
WARM FRONTAL BOUNDARY STRETCHED ACROSS MY SOUTH...ROUGHLY ALONG A
BJI TO JMS LINE. POOL OF 70+ DEW POINTS ARE JUST SOUTH OF THE
BOUNDARY WITH DEW POINTS IN THE MID 50S ACROSS THE NORTH. CAPES
AROUND 2500 J/KG ACROSS THE SOUTH LACK THE SHEAR FOR ANY
SIGNIFICANT ACTIVITY THIS EVENING...BUT WILL PUT IN ISOLATED
STORMS ALONG THE FRONTAL BOUNDARY INTO THE MID EVENING HOURS.
40+ KT SHEAR BOUNDARY RUNS ROUGHLY ALONG THE HWY 200 CORRIDOR AND
NORTH...SO AGAIN NO SIGNIFICANT SHEAR IN OUR MOST HEATED OUT
REGION. GENERALLY USING A NAM/WRF BLEND THROUGH 06Z THEN
TRANSITION TO A MODEL BLEND FOR MAIN EVENT ON THURSDAY.
FORECAST CHALLENGE WILL BE SEVERE POTENTIAL ON THURSDAY.
LATE AFTERNOON/EARLY EVENING...COULD SEE SOME ISOLATED STORMS
ALONG BOUNDARY IN THE SOUTH...HOWEVER THERE IS A LACK OF 0 TO 6 KM
SHEAR.
TONIGHT...WARM FRONTAL BOUNDARY WILL BEGIN TO DRIFT NORTH AS LOW
PRESSURE STRENGTHENS AND MOVES INTO THE WRN DAKOTAS. ISENTROPIC
LIFT/WARM ADVECTION WITH A VERY MOIST AIRMASS WILL HELP INITIATE
SHOWERS/TSTMS ACROSS THE NORTH...IN REGION OF STRONGER SHEAR
ALOFT. THEREFORE COULD SEE SOME STRONG STORMS AFT AROUND
09Z...WHEN MODELS MOST AGREE ON PLACEMENT/TIMING OF PRECIP.
THURSDAY...WARM FRONTAL BOUNDARY WILL LIFT NORTHWARD TO ALONG THE
HWY 200 CORRIDOR BY 12Z AND NORTH OF GFK BY 18Z. SOUTHERN HALF OF
THE CWA SHOULD HEAT UP MUCH LIKE TODAY...WITH CAPES NEARING 3K
J/KG BY MID AFTN. FRONTAL BOUNDARY WILL BE FURTHER NORTH AND
MODELS SHOWING SHEAR VALUES OF 50 KT ALONG INTL BORDER. SEVERE
THREAT CONTINUES ALONG THE NORTHERN THIRD OF THE CWA...WITH
SOUTHERN TWO THIRDS MORE QUESTIONABLE DUE TO CONVECTIVE
INHIBITION. ALTHOUGH FREEZING LEVELS WILL BE QUITE HIGH...LARGE
HAIL A GOOD POSSIBILITY. ALSO A THREAT FOR TORNADOES WITH SFC
BOUNDARY ACROSS NORTHERN ZONES. POTENTIAL EXISTS FOR HEAT
ADVISORY CRITERIA ACROSS SOUTHERN HALF OF CWA. CURRENT FCST HOURLY
TEMPS ARE A COUPLE OF DEG TWO LOW TO ISSUE AT THIS POINT...AND
WILL PUNT TO EVENING SHIFT TO ASSESS 00Z MODEL RUNS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 256 PM CDT WED JUL 17 2013
FRIDAY AND SATURDAY...NORTHWEST FLOW PATTERN BEHIND DEPARTING SYSTEM
WILL BRING A CHANCE FOR SOME ISOLATED SHOWERS/TSTMS ON
FRIDAY...MAINLY IN THE EAST...WITH MODELS DIFFERING ON TIMING.
SIGNIFICANT DIFFERENCES BETWEEN MID RANGE MODELS FOR END OF THE WEEK
ON INTO THE WEEKEND...WITH GFS DROPPING HIGH PRESSURE INTO THE
MANITOBA LAKES REGION WITH MUCH COOLER AIR FILTERING INTO NORTH
DAKOTA (UPPER 60S). ECMWF BRINGS HIGH PRESSURE FURTHER
EAST...ALLOWING RETURN FLOW/WARM ADVECTION TO BRING MAX TEMPS INTO
THE MID TO UPPER 70S. WILL KEEP CONSALL BLEND GOING FOR THIS
PERIOD..HOWEVER THINK GFS-LIKE TEMPS WOULD BE WISHFUL THINKING FOR
MID JULY. CONSALL IS ONLY SLIGHTLY COOLER THAN ECMWF...WHICH IS
STILL COOLER THAN SEASONAL NORMS...SO SATURDAY SHOULD BE PLEASANT
EITHER WAY.
SUNDAY-WEDNESDAY...UPPER FLOW WILL BE MORE NORTHWEST DURING THIS
PERIOD ACCORDING TO THE EXTENDED MODELS. SHORTWAVES WITHIN THIS
PATTERN WILL BE HARD TO TIME. ANTICIPATE A MOSTLY DRY PERIOD WITH
ISOLATED TO SCATTERED THUNDERSTORMS. THE BEST THUNDERSTORM CHANCES
APPEAR TO BE WITH A STRONGER FROPA ON MONDAY...ALTHOUGH COVERAGE
SHOULD BE LIMITED. TEMPERATURES WILL BE NEAR NORMAL VALUES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1142 PM CDT WED JUL 17 2013
ISSUE THIS TAF IS THUNDERSTORM TIMING AT EACH OF THE TAF SITES.
VERY HARD TO HAVE ANY GOOD TIMING AT ANY SITE...THUS WENT SOME
PERIODS OF VCTS RIGHT NOW...AND TIMING DOWN A TEMPO OR PREDOMINATE
PERIOD RIGHT NOW IS VERY DIFFICULT AND LET TAFS BE UPDATED AS
TIMING BECOMES MORE CONFIDENT. GENERALLY EXPECT ISOLD-SCT
CONVECTION NR DVL-GFK-TVF-BJI TAF SITES OVERNIGHT INTO
THURSDAY...WITH FARGO LESS CHANCE. WINDS TO STAY GENERALLY EAST
DVL-GFK-TVF INTO THURSDAY MORNING WITH WIND AT FARGO TURNING BACK
SOUTHERLY AS FRONT MOVES BACK NORTH.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...RIDDLE
SHORT TERM...SPEICHER
LONG TERM...TG/SPEICHER
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
139 AM EDT THU JUL 18 2013
.SYNOPSIS...
A LARGE AREA OF HIGH PRESSURE WILL CONTINUE TO DOMINATE THE
WEATHER ACROSS THE OHIO VALLEY THROUGH THURSDAY. THE HIGH WILL
BEGIN TO BREAK DOWN AND DRIFT SOUTH ON FRIDAY. THIS WILL ALLOW A
COLD FRONT TO DROP ACROSS THE AREA ON SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
TEMPS HAVE STARTED TO FALL SO HEAT ADVISORY HAS BEEN ALLOWED TO
EXPIRE FOR NOW. CONVECTION HAS DISSIPATED AGAIN THIS EVENING AS
EXPECTED. HRRR AND RUC DO ALLOW A BRIEF ISOLATED CONVECTIVE CELL TO
DEVELOP HERE AND THERE OVERNIGHT BUT OTHER THAN THE LEFTOVER CELLS
IN CANADA DROPPING SE TOWARD LERI THINK THE AIRMASS IS TOO CAPPED
FOR ANYTHING TO DEVELOP ELSEWHERE.
ANOTHER WARM AND MUGGY NIGHT. SOME PATCHY FOG MAY DEVELOP BUT NOT
EXPECTING A LOT.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY NIGHT/...
NO BIG CHANGES IN STORE FOR THURSDAY. CERTAINLY POSSIBLE TO GET A
ROGUE THUNDERSTORM WITH THE INSTABILITY SIMILAR TO TODAY BUT FOR
NOW WILL HAVE NO MENTION GIVEN LOW PROBABILITY. ISSUED A HEAT
ADVISORY FOR THURSDAY WITH HIGHS A DEGREE OR SO HIGHER DURING THE
AFTERNOON WITH SIMILAR DEWPOINTS. SHOULD AGAIN HAVE HEAT INDEX
CLOSE TO 100. THURSDAY NIGHT INTO FRIDAY WESTERLIES BEGIN TO
DESCEND ACROSS THE AREA AS UPPER HIGH AXIS SHIFTS SOUTH. WILL HAVE
SLIGHT CHANCE POPS FOR FRIDAY AFTERNOON AND THEN INCREASE TO HIGH
CHANCE AND LIKELY POPS IN ADVANCE OF AND WITH THE FRONT FRIDAY
NIGHT AND SATURDAY. TEMPS AROUND 90 OR A BIT HIGHER THURSDAY AND
FRIDAY. LOW TO MID 80S SATURDAY.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
HIGH PRESSURE ACROSS THE CENTRAL GREAT LAKES STAYS NORTH OF OUR
AREA...SLIDING EAST EARLY NEXT WEEK. THEREFORE AREA WILL GET A
REPRIEVE FROM RECENT HEAT AND TEMPERATURES WILL BE SITTING CLOSE TO
NORMALS. SUNDAY/SUNDAY NIGHT WILL BE DRY WITH HIGH PRESSURE
OVERHEAD...BUT LESS CERTAINTY INTO MONDAY AND TUESDAY WITH SOME
RETURNING MOISTURE TO THE AREA. THE BIG PICTURE KEEPS A MODERATE
TROUGH ACROSS THE NORTHERN TWO THIRDS OF THE EAST U.S. ANY TRUE
FRONTAL PASSAGE LOOKS TO HOLD OFF UNTIL MID WEEK.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
THERE WILL BE PATCHY MVFR FOG AGAIN AROUND SUNRISE. OTHERWISE
EXPECT VFR CONDITIONS THROUGH THE DAY WITH AFTERNOON CUMULUS. IF
ANY ISOLATED CONVECTION CAN DEVELOP IT APPEARS IT WILL BE EAST OF
A LINE FROM MENTOR TO YOUNGSTOWN.
.OUTLOOK...NON VFR IN PATCHY EARLY MORNING FOG.
&&
.MARINE...
HIGH PRESSURE ACROSS THE AREA SLOWLY WEAKENS THROUGH FRIDAY. A COLD
FRONT WILL BE CROSSING THE GREAT LAKES BETWEEN FRIDAY AND SATURDAY.
WINDS AHEAD OF THIS FRONT WILL PICK UP SOME...LIKELY GENERATING 3 TO
5 FOOT WAVES IN THE EASTERN OPEN WATERS FRIDAY AFTERNOON. SMALL
CRAFT ADV CONDITIONS FOR THE NEARSHORE WATERS WILL LIKELY BE DELAYED
UNTIL THE FRONTAL PASSAGE...FOR FRIDAY NIGHT AND SATURDAY.
SHOWERS/THUNDERSTORMS WILL ACCOMPANY THIS COLD FRONT. HIGH PRESSURE
FOLLOWS IN ITS WAKE OVER THE REST OF THE WEEKEND...KEEPING A LIGHTER
NORTH FLOW ACROSS LAKE ERIE.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 8 PM EDT THIS
EVENING FOR OHZ003-006>011-013-017>023-027>033-036>038-
047.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TK
NEAR TERM...ADAMS/TK
SHORT TERM...TK
LONG TERM...OUDEMAN
AVIATION...MULLEN
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS TULSA OK
1237 PM CDT THU JUL 18 2013
.DISCUSSION...
ELEVATED HEATING ON THE HIGHER TERRAIN HAS ONCE AGAIN SET OFF SOME
ISOLATED TO WIDELY SCATTERED SHOWERS AS OF 1230 PM. THE LATEST
DATA FROM THE HRRR SUGGESTS THAT THESE AFTERNOON POPCORN SHOWERS
AND STORMS COULD ENCOMPASS MUCH OF EASTERN OKLAHOMA AND NORTHWEST
ARKANSAS BY LATER IN THE AFTERNOON. SLIGHT CHANCE POPS HAVE BEEN
EXPANDED NORTH AND WEST SOME...TO INCLUDE MOST AREAS EAST OF
HIGHWAY 75. UPDATED PRODUCTS HAVE BEEN SENT.
LACY
&&
.PREV DISCUSSION... /ISSUED 1218 PM CDT THU JUL 18 2013/
DISCUSSION...
THE 18Z TAF DISCUSSION IS INCLUDED BELOW.
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
VFR CONDITIONS WILL PREVAIL FOR THE NEXT 24 HOURS. SMALL CHANCES
FOR A TSTM OVR SE OK/W CNTRL AR COULD AFFECT KMLC AND KFSM TAFS.
WILL LEAVE OUT MENTION FOR NOW...AN AMEND MAY BE NEEDED LATER. AFTER
SOME DENSE FOG AT KFYV 2 NIGHTS AGO...THERE WAS NO MORNING FOG
THIS MORNING. THEREFORE...WILL NOT INCLUDE A MENTION OF FOG IN
THIS SET OF TAFS AS THE GUIDANCE WOULD SUGGEST.
LACY
PREV DISCUSSION... /ISSUED 552 AM CDT THU JUL 18 2013/
DISCUSSION...
VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD...THOUGH AT LEAST
BRIEF MVFR VISIBILITY REMAINS POSSIBLE AT KFYV/KBVO EARLY THIS
MORNING. ISOLATED THUNDERSTORMS POSSIBLE OVER FAR SE OKLAHOMA AND
WESTERN WITH IMPACTS BRIEF AND VERY LOCALIZED.
PREV DISCUSSION... /ISSUED 330 AM CDT THU JUL 18 2013/
DISCUSSION...
FAIRLY TYPICAL SUMMER WEATHER ANTICIPATED FOR MUCH OF THE FORECAST
PERIOD...WITH OUR AREA REMAINING UNDER UPPER RIDGING CONDITIONS.
SHORT RANGE GUIDANCE SUGGESTS SOME WEAKNESS IN THE UPPER RIDGE TODAY
AND FRIDAY...AND WILL CONTINUE WITH AFTERNOON LOW POPS MAINLY FOR
PARTS OF SE OK/NW AR. HIGHS EXPECTED TO BE IN THE 90S AREAWIDE...AND
CURRENT DEWPOINT FORECAST WILL KEEP HEAT INDEX VALUES BELOW ADVISORY
CRITERIA.
A WEAK FRONTAL BOUNDARY IS EXPECTED TO DROP INTO KS AND MO OVER THE
WEEKEND...ALTHOUGH IT LOOKS TO REMAIN JUST TO OUR NORTH. HAVE KEPT
SLIGHTLY HIGHER POPS ACROSS FAR NE OK/NW AR...NEAREST THE
BOUNDARY...FOR BOTH SATURDAY AND SUNDAY.
NWLY FLOW ALOFT WILL DEVELOP ACROSS THE CNTRL PLAINS SUNDAY AND INTO
EARLY NEXT WEEK...WITH OUR AREA REMAINING JUST ALONG THE SRN EDGE OF
THE STRONGER FLOW. THIS PATTERN SUGGESTS THAT THE BULK OF CONVECTION
SHOULD REMAIN TO OUR NORTH...BUT WILL NEED KEEP AN EYE ON MCS
ACTIVITY POTENTIALLY GRAZING SOME OF OUR AREA. STRONGER LOW-LEVEL
SWLY FLOW WILL SUPPORT A SLIGHT WARMUP...WITH AFTERNOON TEMPS
PUSHING THE UPPER 90S TO NEAR 100 ACROSS PARTS OF ERN OK GOING INTO
MID-WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 96 74 96 75 / 10 10 10 10
FSM 96 74 97 74 / 20 10 20 10
MLC 94 71 95 72 / 20 10 10 10
BVO 96 68 96 72 / 10 0 10 10
FYV 93 68 92 70 / 20 10 20 10
BYV 91 69 93 71 / 20 10 20 10
MKO 95 71 96 73 / 20 10 10 10
MIO 97 72 96 74 / 10 10 10 10
F10 94 72 95 73 / 10 10 10 10
HHW 94 73 96 73 / 20 10 20 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...30
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1032 PM EDT FRI JUL 19 2013
.SYNOPSIS...
HIGH PRESSURE WILL WEAKEN AND TRACK EAST THROUGH SATURDAY. A COLD
FRONT WILL APPROACH THE AREA FROM THE NORTHWEST ON SUNDAY...STALLING
AND DISSIPATING IN THE VICINITY THROUGH EARLY NEXT WEEK. AN UPPER
LEVEL TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE EAST TUESDAY AND
MOVE THROUGH THE AREA ON WEDNESDAY...WITH A SECOND WEAK COLD FRONT
ARRIVING FROM THE NORTHWEST FRIDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
1000 PM UPDATE...A CLUSTER OF TSTMS CONTINUES TO PROPAGATE ACRS NE
TENN...BUT ATTM THE CWFA IS FREE OF CONVECTION. SPC MESOANALYSIS
SHOWS SBCAPES STILL NEAR 2000 J IN THE MTNS...STILL WITHOUT CIN IN
THE VICINITY OF THOSE CELLS...SO THEY MAY SURVIVE FOR A TIME THIS
EVENING. MEAN WIND IS WSW WHICH MAY TAKE THEM ACROSS OUR NRN MTN
ZONES...THOUGH I THINK THEY MAY NOT LAST LONG ENOUGH TO DO THAT.
LINE OF CELLS ALSO EVIDENT ACRS N CENTRAL GA ON A NWD TRACK WHICH
SHOULD MISS US. CIN LIKELY TOO STRONG TO ALLOW ANY NEW DEVELOPMENT
IN OUR AREA. HAVE TRIMMED POPS BACK TO UNMENTIONABLY LOW VALUES
OVERNIGHT...BUT KEPT PATCHY FOG WORDING FOR MOST OF THE CWFA.
AT 220 PM EDT FRIDAY...AN UPPER TROUGH WILL SLOWLY AMPLIFY OVER THE
GREAT LAKES TONIGHT AND SATURDAY...WHILE AN ATLANTIC UPPER RIDGE
PROGRESSES FARTHER OUT TO SEA. MEANWHILE...A COLD FRONT WILL MOVE
SOUTHEAST...FROM THE UPPER MS RIVER VALLEY TO THE OH RIVER VALLEY.
LIGHT SSW LOW LEVEL FLOW WILL MAINTAIN RICH MOISTURE OVER OUR AREA
BELOW 700 MB. THE MODELS DISAGREE ON WEATHER THIS AFTERNOON OR
SATURDAY AFTERNOON WILL HAVE BETTER INSTABILITY...BUT ENOUGH SHOULD
BE PRESENT FOR SCATTERED CONVECTION EACH DAY...WITH THE BETTER
COVERAGE IN THE MOUNTAINS DUE TO OROGRAPHIC EFFECTS. WITH WEAK
SHEAR...STORM ORGANIZATION SHOULD BE LIMITED. STEERING FLOW IS
GENERALLY SHOWN TO BE LIGHT IN MODEL SOUNDINGS...SUGGESTING THAT
SLOW TRACKING STORMS COULD PRODUCE HEAVY PRECIPITATION...AND PERHAPS
ISOLATED FLASH FLOODING.
MINIMUM TEMPERATURES TONIGHT WILL BE ABOVE NORMAL TONIGHT IN A
MOIST ATMOSPHERE. MAXIMUM TEMPERATURES SATURDAY WILL BE SLIGHTLY
COOLER THAN TODAY AND NEAR NORMAL AS HEIGHTS FALL ALOFT.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AT 215 PM EDT FRIDAY...AN UNSETTLED PERIOD IS SETTING UP FOR THE
SHORT TERM AS AN UPPER TROUGH AMPLIFIES OVER THE GREAT LAKES THROUGH
THE WEEKEND. A COLD FRONT WILL MOVE SLOWLY SOUTHEAST FROM THE OHIO
VALLEY AND SETTLE OVER NORTH CAROLINA ON SUNDAY AFTERNOON AND THEN
MOVE NORTH AGAIN ON MONDAY. AS THE UPPER TROUGH AMPLIFIES TO THE
NORTH...A LIGHT ZONAL FLOW ALOFT WILL DEVELOP ON SUNDAY AND THEN
BECOME SW ON MONDAY AS A SHORT WAVE APPROACHES.
LOOKS LIKE CONVECTION WILL STILL HAVE MAINLY A DIURNAL
MODE...ESPECIALLY SAT NIGHT WHEN NO APPARENT FORCING WILL BE IN
PLACE TO MAINTAIN UPDRAFTS AFTER THE LOSS OF HEATING. HENCE...RAMPED
POPS DOWN QUICKLY SAT EVENING. ON SUN...SHOWERS/STORMS ARE EXPECTED
TO BECOME NUMEROUS AGAIN BY AFTERNOON OVER THE MOUNTAINS AS THE WEAK
FRONT DROPS INTO THE NORTHERN PORTION OF AREA. SHOULD SEE AT LEAST
SCT SHOWERS/THUNDERSTORMS ELSEWHERE AS SBCAPES APPROACH 1500J DURING
THE AFTERNOON. CONVECTION LOOKS LIKE IT WILL BE SLOWER TO ABATE SUN
NIGHT AS UPPER DIVERGENCE IMPROVES...BUT HAVE BACKED POPS DOWN
TO <15% OUTSIDE OF THE MOUNTAINS AFTER MIDNIGHT.
ON MONDAY...EXPECT ANOTHER DAY WHERE SHOWERS/THUDNERSTORMS WILL
BECOME NUMEROUS DURING THE AFTERNOON HOURS AS A SHORT WAVE
APPROACHES FROM THE WEST AND UPPER DIVERGENCE CONTINUES. USED A
CONSENSUS APPROACH TO GRID FIELDS. MAX TEMPS ARE FORECAST TO BE
ABOUT A CATEGORY SHY OF AVERAGE DUE TO INCREASED CLOUD COVER AND
PRECIP COVERAGE. LOWS WILL BE A LITTLE ABOVE AVERAGE.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AT 200 PM EDT FRIDAY...BOTH THE ECMWF AND GFS INDICATE THAT A H5
TROF WILL START TO AMPLIFY ACROSS THROUGH SOUTHERN APPALACHIAN
REGION ON TUESDAY. A SHORT WAVE EMBEDDED IN THE TROF AXIS IS
EXPECTED TO RIPPLE ACROSS THE FORECAST AREA DURING THE HEAT OF TUES
AFTERNOON. FORECAST SOUNDINGS INDICATE THAT MILD MID LEVEL
TEMPERATURES WILL REMAIN OVER THE REGION...RESULTING CAPE VALUES OF
500-1000 J/KG. THE PASSAGE OF THE S/W COMBINED WITH THE POOL OF
MARGINAL CAPES TO SUPPORT INCREASING COVERAGE THROUGH THE AFTERNOON.
I WILL FORECAST LIKELY POPS ACROSS THE MTNS WITH HIGH CHC EAST. HIGH
TEMPERATURES UNDER DECREASING THICKNESSES AND PARTLY TO MOSTLY
CLOUDY SKY COVER SHOULD REMAIN A COUPLE OF DEGREES BELOW NORMAL.
WEDNESDAY AND THURSDAY...THE LONG WAVE TROUGH WILL REMAIN OVER THE
REGION. GFS FORECAST SOUNDINGS INDICATE THAT MID LEVEL TEMPERATURES
WILL SLOWLY COOL...RESULTING IN AN INCREASE IN CAPES FROM DAY TO
DAY. WEAK DISTURBANCES WILL LIKELY CONTINUE TO TRACK ACROSS THE
REGION...SUPPORTING SCT TO NUM SHRA/TSRA DURING THE EAST OF THE
AFTERNOON. THE GREATEST COVERAGE SHOULD OCCUR OVER THE MTNS.
TEMPERATURES SHOULD CONTINUE TO RANGE 2-3 DEGREES BELOW NORMAL.
FRIDAY...MEDIUM RANGE GUIDANCE INDICATES THAT THE L/W TROUGH AXIS
WILL PIVOT EAST OF THE CWA. DRIER AIR MAY ARRIVE FROM THE WEST...IN
THE WEAK OF A WEAK COLD FRONT. HOWEVER...MOISTURE WILL LIKELY LINGER
ACROSS THE FOOTHILLS AND PIEDMONT. GFS FORECAST SOUNDINGS CONTINUE
TO INDICATE MARGINAL DIURNAL CAPE ACROSS THE REGION. IT APPEARS THAT
AT LEAST SCT SHRA/TSRA WILL DEVELOP ALONG AND AHEAD OF THE SFC
BOUNDARY. I WILL FORECAST 30 TO 40 POPS ACROSS THE REGION.
TEMPERATURES WILL REMAIN COMPARABLE TO THE TUES THROUGH WED PERIOD.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...NC PIEDMONT CONVECTION SHOWING DIMINISHING TREND AT TAF
ISSUANCE TIME BUT THERE IS AN OUTSIDE CHANCE OF SOME REDEVELOPMENT
THRU 01Z...THOUGH THIS IS EVEN LESS LIKELY TO AFFECT THE AIRFIELD.
SOME GUIDANCE INCLUDING LATEST RAP AND 18Z NAM BRING LOW STRATUS UP
FROM THE SOUTH ON LIGHT SLY WINDS AFTER MIDNIGHT. LOW-MID LEVEL
MOISTURE LIKELY TO INCREASE BUT I DON/T ANTICIPATE A CIG FROM THE
CLOUDS. THUS FEW020...WITH LIGHT FOG NEAR MVFR THRESHOLD AS WELL.
ANOTHER CYCLE OF DIURNAL TSRA EXPECTED ACRS THE AREA TOMORROW.
CHANCES IN PROB30 RANGE. GIVEN PLENTIFUL MOISTURE FAIRLY LOW CU WILL
POP OUT BY MID MORNING LIFTING TO VFR LEVEL MIDDAY. S WINDS CONTINUE.
ELSEWHERE...TSRA/SHRA SHOULD CONTINUE OVER THE MTNS FOR A COUPLE HRS
EARLY THIS EVENING BUT KAVL AND OTHER SITES SHOULD REMAIN FREE OF
THE EFFECTS. ANOTHER MOIST NIGHT EXPECTED WITH PATCHY MVFR FOG IN
THE FOOTHILLS/PIEDMONT AND A PRETTY SOLID PERIOD OF IFR TO LIFR FOG
IN MTN VALLEYS...INCLUDING KAVL. LIGHT SLY FLOW EXPECTED TO BRING IN
SOME BETTER LOW-MID LEVEL MOISTURE AND STRATUS AFTER MIDNIGHT THOUGH
NOT FORMING A CIG. ON SATURDAY INITIALLY LOW BASED MORNING CU WILL
FORM...MAKING A VFR CIG BY EARLY AFTN...WITH SIMILAR PRECIP CHANCES
TO THOSE FRI. PROB30 FOR MVFR TSRA AT ALL SITES.
OUTLOOK...A COLD FRONT WILL SAG SEWD INTO THE AREA THIS WEEKEND.
EXPECT ABOVE NORMAL TSRA COVERAGE SUNDAY AND INTO EARLY NEXT
WEEK...WITH BEST CHANCES STILL DURING AFTERNOONS AND EVENINGS.
CONFIDENCE TABLE...
02-08Z 08-14Z 14-20Z 20-02Z
KCLT HIGH 100% HIGH 94% LOW 57% LOW 58%
KGSP HIGH 100% HIGH 93% HIGH 85% HIGH 100%
KAVL HIGH 93% MED 75% HIGH 97% HIGH 100%
KHKY HIGH 94% HIGH 94% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 94% HIGH 85% HIGH 100%
KAND HIGH 88% HIGH 94% MED 78% 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...GOODMAN
NEAR TERM...JAT/WIMBERLEY
SHORT TERM...LG
LONG TERM...GOODMAN/NED
AVIATION...WIMBERLEY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
755 PM EDT FRI JUL 19 2013
.SYNOPSIS...
HIGH PRESSURE WILL WEAKEN AND TRACK EAST THROUGH SATURDAY. A COLD
FRONT WILL APPROACH THE AREA FROM THE NORTHWEST ON SUNDAY...STALLING
AND DISSIPATING IN THE VICINITY THROUGH EARLY NEXT WEEK. AN UPPER
LEVEL TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE EAST TUESDAY AND
MOVE THROUGH THE AREA ON WEDNESDAY...WITH A SECOND WEAK COLD FRONT
ARRIVING FROM THE NORTHWEST FRIDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
700 PM UPDATE...REVISED POP TRENDS PER RADAR...WHICH ONCE AGAIN IS
SHOWING A LATE DAY UPTICK IN COVERAGE POSSIBLY DUE TO LOWER LCLS
CAUSED BY SLIGHT RISES IN DEWPOINTS AS MIXED LAYER BECOMES MORE
SHALLOW. WITH CELLS SHOWING VERY SLOW MOVEMENT GENERALLY KEPT HIGHER
POPS NEAR WHERE THEY ARE CURRENTLY PERSISTING. AN OUTFLOW BDY IS
ALSO ENTERING THE SC PIEDMONT PER KCAE RADAR...AND A CELL DID
BRIEFLY BLOW UP IN MCCORMICK CO WITH THIS FEATURE. CHANCES THUS
SLIGHTLY HIGHER OVER THE NEXT HOUR OR SO IN THE SERN BORDER AREAS.
AT 220 PM EDT FRIDAY...AN UPPER TROUGH WILL SLOWLY AMPLIFY OVER THE
GREAT LAKES TONIGHT AND SATURDAY...WHILE AN ATLANTIC UPPER RIDGE
PROGRESSES FARTHER OUT TO SEA. MEANWHILE...A COLD FRONT WILL MOVE
SOUTHEAST...FROM THE UPPER MS RIVER VALLEY TO THE OH RIVER VALLEY.
LIGHT SSW LOW LEVEL FLOW WILL MAINTAIN RICH MOISTURE OVER OUR AREA
BELOW 700 MB. THE MODELS DISAGREE ON WEATHER THIS AFTERNOON OR
SATURDAY AFTERNOON WILL HAVE BETTER INSTABILITY...BUT ENOUGH SHOULD
BE PRESENT FOR SCATTERED CONVECTION EACH DAY...WITH THE BETTER
COVERAGE IN THE MOUNTAINS DUE TO OROGRAPHIC EFFECTS. WITH WEAK
SHEAR...STORM ORGANIZATION SHOULD BE LIMITED. STEERING FLOW IS
GENERALLY SHOWN TO BE LIGHT IN MODEL SOUNDINGS...SUGGESTING THAT
SLOW TRACKING STORMS COULD PRODUCE HEAVY PRECIPITATION...AND PERHAPS
ISOLATED FLASH FLOODING.
MINIMUM TEMPERATURES TONIGHT WILL BE ABOVE NORMAL TONIGHT IN A
MOIST ATMOSPHERE. MAXIMUM TEMPERATURES SATURDAY WILL BE SLIGHTLY
COOLER THAN TODAY AND NEAR NORMAL AS HEIGHTS FALL ALOFT.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AT 215 PM EDT FRIDAY...AN UNSETTLED PERIOD IS SETTING UP FOR THE
SHORT TERM AS AN UPPER TROUGH AMPLIFIES OVER THE GREAT LAKES THROUGH
THE WEEKEND. A COLD FRONT WILL MOVE SLOWLY SOUTHEAST FROM THE OHIO
VALLEY AND SETTLE OVER NORTH CAROLINA ON SUNDAY AFTERNOON AND THEN
MOVE NORTH AGAIN ON MONDAY. AS THE UPPER TROUGH AMPLIFIES TO THE
NORTH...A LIGHT ZONAL FLOW ALOFT WILL DEVELOP ON SUNDAY AND THEN
BECOME SW ON MONDAY AS A SHORT WAVE APPROACHES.
LOOKS LIKE CONVECTION WILL STILL HAVE MAINLY A DIURNAL
MODE...ESPECIALLY SAT NIGHT WHEN NO APPARENT FORCING WILL BE IN
PLACE TO MAINTAIN UPDRAFTS AFTER THE LOSS OF HEATING. HENCE...RAMPED
POPS DOWN QUICKLY SAT EVENING. ON SUN...SHOWERS/STORMS ARE EXPECTED
TO BECOME NUMEROUS AGAIN BY AFTERNOON OVER THE MOUNTAINS AS THE WEAK
FRONT DROPS INTO THE NORTHERN PORTION OF AREA. SHOULD SEE AT LEAST
SCT SHOWERS/THUNDERSTORMS ELSEWHERE AS SBCAPES APPROACH 1500J DURING
THE AFTERNOON. CONVECTION LOOKS LIKE IT WILL BE SLOWER TO ABATE SUN
NIGHT AS UPPER DIVERGENCE IMPROVES...BUT HAVE BACKED POPS DOWN
TO <15% OUTSIDE OF THE MOUNTAINS AFTER MIDNIGHT.
ON MONDAY...EXPECT ANOTHER DAY WHERE SHOWERS/THUDNERSTORMS WILL
BECOME NUMEROUS DURING THE AFTERNOON HOURS AS A SHORT WAVE
APPROACHES FROM THE WEST AND UPPER DIVERGENCE CONTINUES. USED A
CONSENSUS APPROACH TO GRID FIELDS. MAX TEMPS ARE FORECAST TO BE
ABOUT A CATEGORY SHY OF AVERAGE DUE TO INCREASED CLOUD COVER AND
PRECIP COVERAGE. LOWS WILL BE A LITTLE ABOVE AVERAGE.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AT 200 PM EDT FRIDAY...BOTH THE ECMWF AND GFS INDICATE THAT A H5
TROF WILL START TO AMPLIFY ACROSS THROUGH SOUTHERN APPALACHIAN
REGION ON TUESDAY. A SHORT WAVE EMBEDDED IN THE TROF AXIS IS
EXPECTED TO RIPPLE ACROSS THE FORECAST AREA DURING THE HEAT OF TUES
AFTERNOON. FORECAST SOUNDINGS INDICATE THAT MILD MID LEVEL
TEMPERATURES WILL REMAIN OVER THE REGION...RESULTING CAPE VALUES OF
500-1000 J/KG. THE PASSAGE OF THE S/W COMBINED WITH THE POOL OF
MARGINAL CAPES TO SUPPORT INCREASING COVERAGE THROUGH THE AFTERNOON.
I WILL FORECAST LIKELY POPS ACROSS THE MTNS WITH HIGH CHC EAST. HIGH
TEMPERATURES UNDER DECREASING THICKNESSES AND PARTLY TO MOSTLY
CLOUDY SKY COVER SHOULD REMAIN A COUPLE OF DEGREES BELOW NORMAL.
WEDNESDAY AND THURSDAY...THE LONG WAVE TROUGH WILL REMAIN OVER THE
REGION. GFS FORECAST SOUNDINGS INDICATE THAT MID LEVEL TEMPERATURES
WILL SLOWLY COOL...RESULTING IN AN INCREASE IN CAPES FROM DAY TO
DAY. WEAK DISTURBANCES WILL LIKELY CONTINUE TO TRACK ACROSS THE
REGION...SUPPORTING SCT TO NUM SHRA/TSRA DURING THE EAST OF THE
AFTERNOON. THE GREATEST COVERAGE SHOULD OCCUR OVER THE MTNS.
TEMPERATURES SHOULD CONTINUE TO RANGE 2-3 DEGREES BELOW NORMAL.
FRIDAY...MEDIUM RANGE GUIDANCE INDICATES THAT THE L/W TROUGH AXIS
WILL PIVOT EAST OF THE CWA. DRIER AIR MAY ARRIVE FROM THE WEST...IN
THE WEAK OF A WEAK COLD FRONT. HOWEVER...MOISTURE WILL LIKELY LINGER
ACROSS THE FOOTHILLS AND PIEDMONT. GFS FORECAST SOUNDINGS CONTINUE
TO INDICATE MARGINAL DIURNAL CAPE ACROSS THE REGION. IT APPEARS THAT
AT LEAST SCT SHRA/TSRA WILL DEVELOP ALONG AND AHEAD OF THE SFC
BOUNDARY. I WILL FORECAST 30 TO 40 POPS ACROSS THE REGION.
TEMPERATURES WILL REMAIN COMPARABLE TO THE TUES THROUGH WED PERIOD.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...NC PIEDMONT CONVECTION SHOWING DIMINISHING TREND AT TAF
ISSUANCE TIME BUT THERE IS AN OUTSIDE CHANCE OF SOME REDEVELOPMENT
THRU 01Z...THOUGH THIS IS EVEN LESS LIKELY TO AFFECT THE AIRFIELD.
SOME GUIDANCE INCLUDING LATEST RAP AND 18Z NAM BRING LOW STRATUS UP
FROM THE SOUTH ON LIGHT SLY WINDS AFTER MIDNIGHT. LOW-MID LEVEL
MOISTURE LIKELY TO INCREASE BUT I DON/T ANTICIPATE A CIG FROM THE
CLOUDS. THUS FEW020...WITH LIGHT FOG NEAR MVFR THRESHOLD AS WELL.
ANOTHER CYCLE OF DIURNAL TSRA EXPECTED ACRS THE AREA TOMORROW.
CHANCES IN PROB30 RANGE. GIVEN PLENTIFUL MOISTURE FAIRLY LOW CU WILL
POP OUT BY MID MORNING LIFTING TO VFR LEVEL MIDDAY. S WINDS CONTINUE.
ELSEWHERE...TSRA/SHRA SHOULD CONTINUE OVER THE MTNS FOR A COUPLE HRS
EARLY THIS EVENING BUT KAVL AND OTHER SITES SHOULD REMAIN FREE OF
THE EFFECTS. ANOTHER MOIST NIGHT EXPECTED WITH PATCHY MVFR FOG IN
THE FOOTHILLS/PIEDMONT AND A PRETTY SOLID PERIOD OF IFR TO LIFR FOG
IN MTN VALLEYS...INCLUDING KAVL. LIGHT SLY FLOW EXPECTED TO BRING IN
SOME BETTER LOW-MID LEVEL MOISTURE AND STRATUS AFTER MIDNIGHT THOUGH
NOT FORMING A CIG. ON SATURDAY INITIALLY LOW BASED MORNING CU WILL
FORM...MAKING A VFR CIG BY EARLY AFTN...WITH SIMILAR PRECIP CHANCES
TO THOSE FRI. PROB30 FOR MVFR TSRA AT ALL SITES.
OUTLOOK...A COLD FRONT WILL SAG SEWD INTO THE AREA THIS WEEKEND.
EXPECT ABOVE NORMAL TSRA COVERAGE SUNDAY AND INTO EARLY NEXT
WEEK...WITH BEST CHANCES STILL DURING AFTERNOONS AND EVENINGS.
CONFIDENCE TABLE...
00-06Z 06-12Z 12-18Z 18-24Z
KCLT HIGH 100% HIGH 94% MED 74% LOW 57%
KGSP HIGH 100% HIGH 98% HIGH 81% HIGH 100%
KAVL HIGH 97% MED 76% HIGH 95% HIGH 100%
KHKY HIGH 100% HIGH 91% HIGH 97% HIGH 100%
KGMU HIGH 100% HIGH 97% HIGH 83% HIGH 100%
KAND HIGH 100% HIGH 82% MED 79% 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...GOODMAN
NEAR TERM...JAT/WIMBERLEY
SHORT TERM...LG
LONG TERM...GOODMAN/NED
AVIATION...WIMBERLEY
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1044 PM CDT FRI JUL 19 2013
.UPDATE...
ISSUED AT 1014 PM CDT FRI JUL 19 2013
SHORT WAVE TRACKING SOUTHEAST THROUGH NORTH DAKOTA INTO CENTRAL
MINNESOTA LARGELY ON TRACK TO STAY NORTH AND EAST OF THE FORECAST
AREA TONIGHT. TO THE WEST...SECOND SHORTWAVE NOW TRACKING EAST
SOUTHEAST INTO FAR WESTERN SOUTH DAKOTA IS A BIT SLOWER THAN
EXPECTED. HAVE SLOWED THE ARRIVAL AND EASTWARD PROGRESSION OF
PRECIPITATION INTO OUR WESTERN BORDER...WHICH IS SUPPORTED BY THE
MOST RECENT NAM...HRRR AND RAP MODEL RUNS...UNTIL AROUND 8 TO 9Z.
ACTIVITY WOULD LIKELY BE LIMITED TO AREAS WEST OF I-29 TONIGHT
THROUGH AROUND MID MORNING SATURDAY BEFORE DIMINISHING. WITH VERY DRY
MID LEVELS...ANY THUNDERSTORMS WILL BE HIGH BASED AND RATHER LIGHT.
WILL ALSO LIMIT COVERAGE TO SCATTERED SHOWERS AND THUNDERSTORMS GIVEN
THE WARM AND DRY MID LEVELS.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 245 PM CDT FRI JUL 19 2013
RAPID FLOW CONTINUING TO DEVELOP ALOFT...ALONG WITH CONTINUED SHORT
WAVES APPROACHING AND PASSING IN FLOW...SHOULD BRING AN INCREASE IN
RELATIVELY WEAK SCATTERED SHOWERS AND A FEW THUNDERSTORMS FROM THE
SOUTHWEST AND WEST LATE THIS EVENING INTO SATURDAY.PRECIPITATION
SHOULD HOLD OFF UNTIL SATURDAY MORNING SPREADING INTO MOST OF
SOUTHWEST MN...AND INTO THE EASTERN PART OF NORTHWEST IOWA OR
FURTHER EAST AWAY FROM SUX. THE SLOW INCREASE IN INSTABILITY WILL
LIMIT RAINFALL AMOUNTS ESPECIALLY EAST THROUGH SATURDAY BUT EXPECT
QUITE A FEW OF THESE WEAK SHOWERS TO BE AROUND. IN ANY EVENT MID
LEVEL MOISTURE SHOULD INCREASE QUITE A BIT AND CLOUDS SHOULD BE
PLENTIFUL. ALONG WITH THE FURTHER COOLING EXPECTED...THIS SHOULD
LIMIT SURFACE WARMING SATURDAY AND EXPECT HIGHS TO BE CLOSER TO THE
COOLER MET THAN THE WARMER MAV...THE MET MIGHT BE RIGHT WITH MORE
SOLID CLOUD COVER BUT DO EXPECT BREAKS AND A FEW SUNSHINE PERIODS.
AS SUGGESTED...RAINFALL AMOUNTS SHOULD BE FAIRLY TAME...NOT THE HALF
INCH PLUS THE NAM GIVES NORTH OF INTERSTATE 90 SATURDAY DAYTIME.
TEMPERATURES TONIGHT SHOULD BE A LITTLE COOLER THAN WE HAD GONE FOR
EARLIER...EVEN WITH AN INCREASE IN CLOUDS WEST LATER ON. WINDS WILL
BE LIGHT TONIGHT WITH A WEAK EASTERLY FLOW STARTING FROM THE WEST
LATE...AND ONLY SLOWLY DEVELOPING OVER THE AREA SATURDAY.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 245 PM CDT FRI JUL 19 2013
SATURDAY NIGHT STILL POSES A GOOD CHANCE FOR THUNDERSTORMS AS AN
UPPER LEVEL WAVE MOVES THROUGH THE REGION. WHILE SOME OF THE BETTER
CHANCES WILL BE DURING THE DAY FORCING AND INSTABILITY LINGER
THROUGH THE NIGHT...MAINLY IN THE FORM OF A FAIRLY STRONG LOW LEVEL
JET. INSTABILITY A LITTLE DIFFICULT TO ASCERTAIN AS THE MODELS ARE
POLLUTED BY CONVECTION. OTHERWISE LOWS MAINLY IN THE LOWER TO MIDDLE
60S.
SUNDAY LOOKS TO BE A BIT BETWEEN WAVES BUT WITH A BOUNDARY LINGERING
AND COOLER AIR ALOFT CANNOT COMPLETELY RULE OUT THE THREAT FOR A FEW
THUNDERSTORMS. THAT AND IT IS LATE JULY...A TIME WHEN THE MODELS
REPRESENTATION OF WHERE BOUNDARIES ARE GOING TO BE IS SUSPECT AT
BEST.
MONDAY COULD PROVE TO BE AN INTERESTING DAY AS BOTH THE NAM AND GFS
SUGGEST A WEAK WAVE DROPPING SOUTHEAST INTO THE AREA DURING THE
AFTERNOON. WHILE SHEAR IS NOT OVERLY IMPRESSIVE THERE WILL BE AN
INCOMING BOUNDARY WITH SURFACE BASED CAPE VALUES OF ABOUT 3000 J/KG.
CAPPING SHOULD NOT BE A MAJOR PROBLEM WITH ABOUT +10 TO +11 AT
700MB. WILL WAIT AND SEE BUT FOR NOW LOOKS LIKE THERE MAY BE A
THREAT FOR A FEW SEVERE THUNDERSTORMS ON MONDAY.
IN THE TUESDAY THROUGH FRIDAY TIMEFRAME...NORTHWEST FLOW ALOFT
SHOULD LEAD TOWARDS PLEASANT CONDITIONS LOOKING NOT TOO HOT AND NOT
TOO HUMID. THE CHANCE FOR THUNDERSTORMS WILL BE SPORADIC DURING THIS
TIMEFRAME AS EACH OF THE MODELS SWINGS THROUGH MARGINAL UPPER LEVEL
SUPPORT AT DIFFERENT TIMES...SO EXPECTING POPS TO REMAIN AT 30
PERCENT OR LESS EACH DAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1036 PM CDT FRI JUL 19 2013
VFR CONDITIONS EXPECTED THROUGH MUCH OF THE PERIOD. LIGHT WINDS
OVERNIGHT WILL PICK UP A BIT OUT OF THE SOUTHEAST ON SATURDAY
MORNING. SCATTERED CONVECTION MAY DEVELOP THROUGH CENTRAL SOUTH
OVERNIGHT...POSSIBLY AFFECTING KHON DURING THE MORNING...WITH
POSSIBLE REDEVELOPMENT IN THE AFTERNOON. WHILE CANNOT RULE OUT
ISOLATED CONVECTION AT KFSD AND KSUX DURING THE DAY ON
SATURDAY...CONFIDENCE IS LOW...WITH A BETTER CHANCE SATURDAY
EVENING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...
SHORT TERM...
LONG TERM...08
AVIATION...JM
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1024 PM CDT FRI JUL 19 2013
.UPDATE...
ISSUED AT 1014 PM CDT FRI JUL 19 2013
SHORT WAVE TRACKING SOUTHEAST THROUGH NORTH DAKOTA INTO CENTRAL
MINNESOTA LARGELY ON TRACK TO STAY NORTH AND EAST OF THE FORECAST
AREA TONIGHT. TO THE WEST...SECOND SHORTWAVE NOW TRACKING EAST
SOUTHEAST INTO FAR WESTERN SOUTH DAKOTA IS A BIT SLOWER THAN
EXPECTED. HAVE SLOWED THE ARRIVAL AND EASTWARD PROGRESSION OF
PRECIPITATION INTO OUR WESTERN BORDER...WHICH IS SUPPORTED BY THE
MOST RECENT NAM...HRRR AND RAP MODEL RUNS...UNTIL AROUND 8 TO 9Z.
ACTIVITY WOULD LIKELY BE LIMITED TO AREAS WEST OF I-29 TONIGHT
THROUGH AROUND MID MORNING SATURDAY BEFORE DIMINISHING. WITH VERY DRY
MID LEVELS...ANY THUNDERSTORMS WILL BE HIGH BASED AND RATHER LIGHT.
WILL ALSO LIMIT COVERAGE TO SCATTERED SHOWERS AND THUNDERSTORMS GIVEN
THE WARM AND DRY MID LEVELS.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 245 PM CDT FRI JUL 19 2013
RAPID FLOW CONTINUING TO DEVELOP ALOFT...ALONG WITH CONTINUED SHORT
WAVES APPROACHING AND PASSING IN FLOW...SHOULD BRING AN INCREASE IN
RELATIVELY WEAK SCATTERED SHOWERS AND A FEW THUNDERSTORMS FROM THE
SOUTHWEST AND WEST LATE THIS EVENING INTO SATURDAY.PRECIPITATION
SHOULD HOLD OFF UNTIL SATURDAY MORNING SPREADING INTO MOST OF
SOUTHWEST MN...AND INTO THE EASTERN PART OF NORTHWEST IOWA OR
FURTHER EAST AWAY FROM SUX. THE SLOW INCREASE IN INSTABILITY WILL
LIMIT RAINFALL AMOUNTS ESPECIALLY EAST THROUGH SATURDAY BUT EXPECT
QUITE A FEW OF THESE WEAK SHOWERS TO BE AROUND. IN ANY EVENT MID
LEVEL MOISTURE SHOULD INCREASE QUITE A BIT AND CLOUDS SHOULD BE
PLENTIFUL. ALONG WITH THE FURTHER COOLING EXPECTED...THIS SHOULD
LIMIT SURFACE WARMING SATURDAY AND EXPECT HIGHS TO BE CLOSER TO THE
COOLER MET THAN THE WARMER MAV...THE MET MIGHT BE RIGHT WITH MORE
SOLID CLOUD COVER BUT DO EXPECT BREAKS AND A FEW SUNSHINE PERIODS.
AS SUGGESTED...RAINFALL AMOUNTS SHOULD BE FAIRLY TAME...NOT THE HALF
INCH PLUS THE NAM GIVES NORTH OF INTERSTATE 90 SATURDAY DAYTIME.
TEMPERATURES TONIGHT SHOULD BE A LITTLE COOLER THAN WE HAD GONE FOR
EARLIER...EVEN WITH AN INCREASE IN CLOUDS WEST LATER ON. WINDS WILL
BE LIGHT TONIGHT WITH A WEAK EASTERLY FLOW STARTING FROM THE WEST
LATE...AND ONLY SLOWLY DEVELOPING OVER THE AREA SATURDAY.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 245 PM CDT FRI JUL 19 2013
SATURDAY NIGHT STILL POSES A GOOD CHANCE FOR THUNDERSTORMS AS AN
UPPER LEVEL WAVE MOVES THROUGH THE REGION. WHILE SOME OF THE BETTER
CHANCES WILL BE DURING THE DAY FORCING AND INSTABILITY LINGER
THROUGH THE NIGHT...MAINLY IN THE FORM OF A FAIRLY STRONG LOW LEVEL
JET. INSTABILITY A LITTLE DIFFICULT TO ASCERTAIN AS THE MODELS ARE
POLLUTED BY CONVECTION. OTHERWISE LOWS MAINLY IN THE LOWER TO MIDDLE
60S.
SUNDAY LOOKS TO BE A BIT BETWEEN WAVES BUT WITH A BOUNDARY LINGERING
AND COOLER AIR ALOFT CANNOT COMPLETELY RULE OUT THE THREAT FOR A FEW
THUNDERSTORMS. THAT AND IT IS LATE JULY...A TIME WHEN THE MODELS
REPRESENTATION OF WHERE BOUNDARIES ARE GOING TO BE IS SUSPECT AT
BEST.
MONDAY COULD PROVE TO BE AN INTERESTING DAY AS BOTH THE NAM AND GFS
SUGGEST A WEAK WAVE DROPPING SOUTHEAST INTO THE AREA DURING THE
AFTERNOON. WHILE SHEAR IS NOT OVERLY IMPRESSIVE THERE WILL BE AN
INCOMING BOUNDARY WITH SURFACE BASED CAPE VALUES OF ABOUT 3000 J/KG.
CAPPING SHOULD NOT BE A MAJOR PROBLEM WITH ABOUT +10 TO +11 AT
700MB. WILL WAIT AND SEE BUT FOR NOW LOOKS LIKE THERE MAY BE A
THREAT FOR A FEW SEVERE THUNDERSTORMS ON MONDAY.
IN THE TUESDAY THROUGH FRIDAY TIMEFRAME...NORTHWEST FLOW ALOFT
SHOULD LEAD TOWARDS PLEASANT CONDITIONS LOOKING NOT TOO HOT AND NOT
TOO HUMID. THE CHANCE FOR THUNDERSTORMS WILL BE SPORADIC DURING THIS
TIMEFRAME AS EACH OF THE MODELS SWINGS THROUGH MARGINAL UPPER LEVEL
SUPPORT AT DIFFERENT TIMES...SO EXPECTING POPS TO REMAIN AT 30
PERCENT OR LESS EACH DAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 625 PM CDT FRI JUL 19 2013
HIGH PRESSURE BUILDING INTO AREA AND DOMINATING THE WEATHER PATTERN.
WINDS WILL CONTINUE TO LESSEN THROUGHOUT THE EVENING AND SKIES
WILL BE CLEAR EARLY ON. AS THE NIGHT GOES ON...SHOWERS AND
THUNDERSTORMS THAT DEVELOP WEST OF THE MISSOURI RIVER THIS EVENING
WILL GRADUALLY MOVE EAST. DONT EXPECT MUCH FROM THE LEFTOVER
STORMS AS THEY MOVE EAST OTHER THAN CLOUD COVER. CIGS AND VSBYS
WILL REMAIN VFR. CHANGED TIMING A LITTLE FROM PREVIOUS FORECASTS
AND WENT WITH TWO DIFFERENT TIME PERIODS WHEN SHOWERS WILL BE
POSSIBLE. MAINLY IN THE 10Z TO 14Z MORNING WINDOW AND AFTER 21Z IN
THE AFTERNOON. BASED ON MODEL DATA...FEEL THE BETTER CHANCES FOR
TAF LOCATIONS TO EXPERIENCE -TSRA WILL MAINLY BE LATE IN TAF
PERIOD.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...
SHORT TERM...
LONG TERM...08
AVIATION...HEITKAMP
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1129 PM CDT WED JUL 17 2013
.UPDATE...FOR 06Z AVIATION FORECAST
&&
.AVIATION...
SHOWERS CONTINUE TO WORK WESTWARD INTO MIDDLE TENNESSEE. UPPER TROUGH
AXIS RUNNING UP ALONG PLATEAU AT 04Z WILL SHIFT WESTWARD OVERNIGHT.
ALTHOUGH CURRENT CONVECTION WILL LIKELY DIMINSH OVER THE NEXT
COUPLE OF HOURS DO THINK WE WILL LIKELY HAVE SOME CONVECTION IN
THE MID STATE DURING THE OVERNIGHT. MOISTURE DEEPENS WHILE OMEGA
INCREASES ON THURSDAY SO LOOK FOR SCATTERED SHOWERS AND
THUNDERSTORMS TO BE MORE NUMEROUS.
BOYD
&&
.PREV DISCUSSION... /ISSUED 1003 PM CDT WED JUL 17 2013/
UPDATE...
SCATTERED STORMS CONTINUE TO DEVELOP ALONG AND EAST OF THE CUMBERLAND
PLATEAU...WORKING SLOWLY WEST. UPPER HIGH CONTINUES TO LINGER OVER
THE MID-WEST/OH VALLEY BUT VERY WEAK INVERTED TROUGH/WAVE SHOWING
UP ACROSS THE APPALACHIANS HEADING WEST AS WELL. THIS WAVE MOVING
OVER THE CWA LITTLE LATER WILL DEEPEN MOISTURE SOME AS WELL AS KEEP
LARGE SCALE ACCENT GOING. CANT RULE OUT ISO TO POSSIBLY SCT STORMS
OVERNIGHT...ESPECIALLY EAST OF BNA. HAVE ADDED BACK FOR MOST OF
THE NIGHT. ALSO EXPECT STORMS TO DEVELOP FAIRLY EARLY TOMORROW
AFTER DYING OFF TOWARD MORNING...SO WILL ADJUST THERE AS WELL.
MINOR TEMP TWEAKS ALSO POSSIBLE.
PREV DISCUSSION... /ISSUED 805 PM CDT WED JUL 17 2013/
UPDATE...
AVIATION...
SHOWERS AND STORMS BEGINNING TO DEVELOP ON EAST SIDE OF PLATEAU
NEAR CROSSVILLE SO HAVE UPDATED TERMINAL FORECAST FOR CROSSVILLE
TO INCLUDE A CHANCE OF THUNDERSTORMS FOR THE NEXT SEVERAL HOURS.
LATEST RUC SHOWING UPPER LEVEL TROUGH OVER EASTERN TENNESSEE
APPROACHING PLATEAU.
BOYD
PREV DISCUSSION... /ISSUED 721 PM CDT WED JUL 17 2013/
UPDATE...FOR 00Z AVIATION FORECAST
AVIATION...
ISOLATED TO SCATTERED CONVECTION ON-GOING IN THE MID STATE AT THIS
TIME. THERE IS A PRETTY GOOD SWATH OF SHOWERS AND STORMS OVER
EASTERN TENNESSEE AND WESTERN CAROLINAS THAT MAY WORK WESTWARD
THIS EVENING AND OVERNIGHT INTO THE MID STATE. THIS ACTIVITY IS
ASSOCIATED WITH AN EASTERLY WAVE THATS BEEN PROGRESSING WESTWARD
WITH TIME. IF THIS TREND CONTINUES THIS ACTIVITY WILL REACH THE
PLATEAU AROUND 02Z-03Z AND CONTINUE WESTWARD LATE EVENING AND
OVERNIGHT. H-TRIPLE-R HI RES BRINGS THIS ACTIVITY UP TO INTERSTATE
65 BY 07Z. LOOK FOR SCATTERED CONVECTION DURING THE DAY ON
THURSDAY.
BOYD
PREV DISCUSSION... /ISSUED 541 PM CDT WED JUL 17 2013/
MESOSCALE UPDATE...
THUNDERSTORMS MOVING THROUGH GRUNDY COUNTY DROPPING RAINFALL OF
ONE TO 1.25 INCHES PER HOUR. STORMS SHOULD EXIT SHORTLY BUT WILL
HAVE TO WATCH UPSTREAM STORMS FOR TRAINING.
BOYD
PREV DISCUSSION... /ISSUED 309 PM CDT WED JUL 17 2013/
DISCUSSION...
CURRENT RADAR TRENDS INDICATE VERY ISOLATED SHOWERS ACROSS MIDDLE
TENNESSEE. VISIBLE SATELLITE IMAGERY SHOWS DIURNAL CU FIELD
DEVELOPED JUST AFTER 15Z TODAY...AND FIGURE THIS WILL BE THE TREND
OVER THE NEXT COUPLE OF DAYS BEFORE A FRONTAL BOUNDARY PUSHES DOWN
THIS WEEKEND. MODELS INDICATE A SLIGHT INCREASE IN MOISTURE FOR
THURSDAY AND FRIDAY...SO AM ANTICIPATING A CORRESPONDING SLIGHT
INCREASE IN SHOWER CHANCES THE NEXT TWO DAYS. UPSTREAM RADAR
TRENDS INDICATE A BROADER COVERAGE OF CONVECTION...AND EXPECT THIS
PATTERN TO SHIFT WESTWARD WHILE WEAKENING SOMEWHAT.
BETTER CHANCES FOR RAIN SHOWERS AND CONVECTION WILL BE THIS
WEEKEND AS FLOW SHIFTS AROUND TO THE SOUTHWEST AHEAD OF A WEAK
FRONTAL BOUNDARY THAT WILL PASS THROUGH BY SUNDAY EVENING. BEHIND
THE FRONT...THE FLOW REMAINS WESTERLY...SO EXPECT LITTLE IN THE
WAY OF RELIEF FROM THE WARM TEMPERATURES AND HUMIDITY. THE UPPER
TROUGH THAT IS EXPECTED TO SET UP OVER THE EASTERN HALF OF THE
U.S. WILL REMAIN IN PLACE THROUGH THE END OF THE FORECAST
PERIOD...WITH THE EXTENDED MODELS HINTING AT A RELIEF PERHAPS BY
NEXT WEEKEND.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION...UPDATED
NWS SAN ANGELO TX
938 PM CDT FRI JUL 19 2013
.UPDATE...
ADDED ISOLATED SHOWERS OVER FAR SOUTHERN SECTIONS AND MADE MINOR
TWEAKED TO DEWPOINTS AND SKY COVER FOR THE REST OF TONIGHT.
&&
.DISCUSSION...
LATEST NAM AND HRRR ARE INDICATING SOME LIGHT RAIN SHOWERS
DEVELOPING ACROSS PORTIONS OF THE NORTHWEST HILL COUNTRY AND
NORTH EDWARDS PLATEAU AFTER 03Z. THIS SEEMS TO BE TIED TO SOME
ENHANCED LOW LEVEL MOISTURE ADVECTION AND WEAK CONVERGENCE ACROSS
THIS AREA. ADDED ISOLATED RAIN SHOWERS ACROSS SOUTHERN COUNTIES
FOR THE OVERNIGHT PERIOD AND TWEAKED DEWPOINTS AND SKY COVER TO
ACCOUNT FOR TRENDS. UPDATED PRODUCTS HAVE BEEN SENT.
&&
.PREV DISCUSSION... /ISSUED 620 PM CDT FRI JUL 19 2013/
DISCUSSION...
SEE THE 00Z AVIATION DISCUSSION BELOW.
AVIATION...
A FEW DIURNAL SHOWERS HAVE DEVELOPED TO THE NORTH OF KABI AND
SOUTHEAST OF KJCT BUT I EXPECT MOST OF THIS TO DISSIPATE WITHIN
THE NEXT 1-2 HOURS AS WE LOSE DAYTIME HEATING. THE CU FIELD WILL
HOLD ON FOR A FEW HOURS BUT SHOULD THIN OVERNIGHT. THERE IS SOME
INDICATION IN THE NAM AND HRRR MODELS THAT NOCTURNAL SHOWERS COULD
DEVELOP SOUTH OF A KSJT TO KBBD LINE TONIGHT BUT CONFIDENCE IS
VERY LOW SO THE TAFS MAINTAIN NO MENTION OF PRECIP. HIGH CLOUDS
WILL CONTINUE TO STREAM FROM THE NORTHWEST TO SOUTHEAST OVERNIGHT
BUT LOW CLOUDS WILL BE THE PRIMARY CONCERN...ESPECIALLY SOUTH OF
KSJT AND KBBD.
PATCHY FOG WILL BE POSSIBLE INTIALLY TONIGHT...MAINLY AFTER
06Z...WITH STRATUS DEVELOPING AT BOTH KSOA AND KJCT NEAR OR BEFORE
12Z. FARTHER NORTH...WE COULD SEE AN HOUR OR TWO OF MVFR
CONDITIONS AS STRATO CU DEVELOP AFTER SUNRISE...CLOSER TO 14-15Z.
BY 15-16Z...VFR CONDITIONS ARE ANTICIPATED ACROSS WEST CENTRAL
TEXAS WITH AN AFTERNOON CU FIELD AROUND 6 KFT. GENERALLY SOUTH
WINDS ARE EXPECTED TO REMAIN AROUND 10 KTS OR LESS...FOLLOWING OUR
TYPICAL DIURNAL TREND OF VEERING TO THE SOUTHWEST IN THE MORNING
AND BACKING TO THE SOUTHEAST DURING THE LATE AFTERNOON AND EVENING
HOURS.
JOHNSON
PREV DISCUSSION... /ISSUED 340 PM CDT FRI JUL 19 2013/
SHORT TERM...
.MUCH QUIETER PATTERN ACROSS WEST CENTRAL TEXAS THIS AFTERNOON...
WEST CENTRAL TEXAS IS BETWEEN SYSTEMS THIS AFTERNOON...WITH THE
UPPER LOW THAT BROUGHT MUCH NEEDED RAINFALL TO THE AREA NOW ACROSS
NORTHWEST MEXICO...AND A SECOND UPPER LOW WORKING ITS WAY INTO
LOUISIANA. SUBSTANTIAL CUMULUS FIELD ACROSS THE AREA THIS
AFTERNOON...BUT THIS CLOUD COVER IS NOT LEADING TO ANY SHOWERS OR
STORMS. VERY LITTLE ENHANCEMENT TO THIS CU FIELD...SO CHANCES OF
ANY DEVELOPMENT ARE SMALL...BUT NOT ZERO...THROUGH SUNSET.
THERE IS CONVECTION ACROSS EAST TEXAS FROM THE LOUISIANA SYSTEM
ACROSS EAST TEXAS THIS AFTERNOON...AND EXPECT IT TO MAKE A RUN
TOWARDS THE HEARTLAND BY SATURDAY AFTERNOON. HOWEVER...LATEST
GLOBAL MODELS AND THE TTU WRF SUGGEST IT WONT QUITE MAKE IT.
WILL KEEP POPS OUT OF THE FORECAST FOR NOW. OTHERWISE...WARM AND
MOIST AIR MASS TO REMAIN IN PLACE. A LITTLE MORE SUN IS ALLOWING
TEMPERATURES TO CLIMB THIS AFTERNOON...AND MORE OF THE SAME FOR
SATURDAY.
LONG TERM...
/SUNDAY THROUGH FRIDAY/
THE MAIN QUESTION IN THE LONG TERM IS WHAT EFFECTS THE RECENT
RAINFALL WILL HAVE ON TEMPERATURES. BUT FIRST...THERE IS A VERY
SLIGHT CHANCE FOR RAIN SUNDAY NIGHT AS A WEAKNESS IN THE RIDGE
DEVELOPS. ALL OF THE MODELS ARE IN FAIRLY GOOD AGREEMENT WITH THE
WEAKNESS DEVELOPING OVER WEST TEXAS AND A LOW DEVELOPING OVER
NORTHERN MEXICO. PREVIOUS MODEL RUNS WERE SUGGESTING THE RAIN
WOULD BE ON MONDAY. LOOKING AT THE GFS ENSEMBLES 12 HOUR RAIN
PROBABILITIES...IT HAS SLIGHTLY BETTER CHANCES SUNDAY NIGHT AND
BACKS OFF FOR MONDAY. THE ECMWF DETERMINISTIC MODEL IS SLIGHTLY
WETTER THAN THE GFS. GIVEN THE LACK OF MUCH SUPPORT AT THE SURFACE
TO INITIATE ANYTHING...I AM GOING WITH MORE OF THE GFS...NAM
SOLUTION AND HAVE SOME SLIGHT CHANCES ACROSS THE NORTHERN EDWARDS
PLATEAU AND NORTHWEST HILL COUNTRY SUNDAY NIGHT.
OTHERWISE...THE RIDGE BUILDS BACK IN AND TEMPERATURES WARM THROUGH
THE END OF NEXT WEEK AS WE BEGIN TO DRY OUT. THE AIR SHOULD STAY
FAIRLY MOIST AS IT WILL TAKE A WHILE FOR THE THE SOIL MOISTURE TO
RETURN TO A MORE NORMAL LEVEL FOLLOWING THE RAIN THIS WEEK. WINDS
WILL STAY OUT OF THE SOUTH TO SOUTHEAST...SO I WOULD NOT EXPECT TO
SEE RAPID DRYING. SOME OF THE MODEL GUIDANCE IS TRYING TO TAKE
TEMPERATURES JUST OVER 100 DEGREES...BUT THIS IS OVER THE AREA
THAT HAS RECEIVED THE HIGHER RAIN AMOUNTS. GIVEN THAT THE HIGHER
SOIL MOISTURE SHOULD HELP TO KEEP TEMPERATURES JUST A BIT
COOLER...I HAVE TENDED TEMPERATURES TOWARDS THE RAW GFS SOLUTION
WITH TEMPERATURES IN THE MID TO UPPER 90S.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 90 71 94 72 94 / 10 10 10 5 5
SAN ANGELO 90 69 93 71 94 / 10 10 10 5 10
JUNCTION 89 69 93 70 93 / 10 10 10 10 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
620 PM CDT FRI JUL 19 2013
.DISCUSSION...
SEE THE 00Z AVIATION DISCUSSION BELOW.
&&
.AVIATION...
A FEW DIURNAL SHOWERS HAVE DEVELOPED TO THE NORTH OF KABI AND
SOUTHEAST OF KJCT BUT I EXPECT MOST OF THIS TO DISSIPATE WITHIN
THE NEXT 1-2 HOURS AS WE LOSE DAYTIME HEATING. THE CU FIELD WILL
HOLD ON FOR A FEW HOURS BUT SHOULD THIN OVERNIGHT. THERE IS SOME
INDICATION IN THE NAM AND HRRR MODELS THAT NOCTURNAL SHOWERS COULD
DEVELOP SOUTH OF A KSJT TO KBBD LINE TONIGHT BUT CONFIDENCE IS
VERY LOW SO THE TAFS MAINTAIN NO MENTION OF PRECIP. HIGH CLOUDS
WILL CONTINUE TO STREAM FROM THE NORTHWEST TO SOUTHEAST OVERNIGHT
BUT LOW CLOUDS WILL BE THE PRIMARY CONCERN...ESPECIALLY SOUTH OF
KSJT AND KBBD.
PATCHY FOG WILL BE POSSIBLE INTIALLY TONIGHT...MAINLY AFTER
06Z...WITH STRATUS DEVELOPING AT BOTH KSOA AND KJCT NEAR OR BEFORE
12Z. FARTHER NORTH...WE COULD SEE AN HOUR OR TWO OF MVFR
CONDITIONS AS STRATO CU DEVELOP AFTER SUNRISE...CLOSER TO 14-15Z.
BY 15-16Z...VFR CONDITIONS ARE ANTICIPATED ACROSS WEST CENTRAL
TEXAS WITH AN AFTERNOON CU FIELD AROUND 6 KFT. GENERALLY SOUTH
WINDS ARE EXPECTED TO REMAIN AROUND 10 KTS OR LESS...FOLLOWING OUR
TYPICAL DIURNAL TREND OF VEERING TO THE SOUTHWEST IN THE MORNING
AND BACKING TO THE SOUTHEAST DURING THE LATE AFTERNOON AND EVENING
HOURS.
JOHNSON
&&
.PREV DISCUSSION... /ISSUED 340 PM CDT FRI JUL 19 2013/
SHORT TERM...
..MUCH QUIETER PATTERN ACROSS WEST CENTRAL TEXAS THIS AFTERNOON...
WEST CENTRAL TEXAS IS BETWEEN SYSTEMS THIS AFTERNOON...WITH THE
UPPER LOW THAT BROUGHT MUCH NEEDED RAINFALL TO THE AREA NOW ACROSS
NORTHWEST MEXICO...AND A SECOND UPPER LOW WORKING ITS WAY INTO
LOUISIANA. SUBSTANTIAL CUMULUS FIELD ACROSS THE AREA THIS
AFTERNOON...BUT THIS CLOUD COVER IS NOT LEADING TO ANY SHOWERS OR
STORMS. VERY LITTLE ENHANCEMENT TO THIS CU FIELD...SO CHANCES OF
ANY DEVELOPMENT ARE SMALL...BUT NOT ZERO...THROUGH SUNSET.
THERE IS CONVECTION ACROSS EAST TEXAS FROM THE LOUISIANA SYSTEM
ACROSS EAST TEXAS THIS AFTERNOON...AND EXPECT IT TO MAKE A RUN
TOWARDS THE HEARTLAND BY SATURDAY AFTERNOON. HOWEVER...LATEST
GLOBAL MODELS AND THE TTU WRF SUGGEST IT WONT QUITE MAKE IT.
WILL KEEP POPS OUT OF THE FORECAST FOR NOW. OTHERWISE...WARM AND
MOIST AIR MASS TO REMAIN IN PLACE. A LITTLE MORE SUN IS ALLOWING
TEMPERATURES TO CLIMB THIS AFTERNOON...AND MORE OF THE SAME FOR
SATURDAY.
LONG TERM...
/SUNDAY THROUGH FRIDAY/
THE MAIN QUESTION IN THE LONG TERM IS WHAT EFFECTS THE RECENT
RAINFALL WILL HAVE ON TEMPERATURES. BUT FIRST...THERE IS A VERY
SLIGHT CHANCE FOR RAIN SUNDAY NIGHT AS A WEAKNESS IN THE RIDGE
DEVELOPS. ALL OF THE MODELS ARE IN FAIRLY GOOD AGREEMENT WITH THE
WEAKNESS DEVELOPING OVER WEST TEXAS AND A LOW DEVELOPING OVER
NORTHERN MEXICO. PREVIOUS MODEL RUNS WERE SUGGESTING THE RAIN
WOULD BE ON MONDAY. LOOKING AT THE GFS ENSEMBLES 12 HOUR RAIN
PROBABILITIES...IT HAS SLIGHTLY BETTER CHANCES SUNDAY NIGHT AND
BACKS OFF FOR MONDAY. THE ECMWF DETERMINISTIC MODEL IS SLIGHTLY
WETTER THAN THE GFS. GIVEN THE LACK OF MUCH SUPPORT AT THE SURFACE
TO INITIATE ANYTHING...I AM GOING WITH MORE OF THE GFS...NAM
SOLUTION AND HAVE SOME SLIGHT CHANCES ACROSS THE NORTHERN EDWARDS
PLATEAU AND NORTHWEST HILL COUNTRY SUNDAY NIGHT.
OTHERWISE...THE RIDGE BUILDS BACK IN AND TEMPERATURES WARM THROUGH
THE END OF NEXT WEEK AS WE BEGIN TO DRY OUT. THE AIR SHOULD STAY
FAIRLY MOIST AS IT WILL TAKE A WHILE FOR THE THE SOIL MOISTURE TO
RETURN TO A MORE NORMAL LEVEL FOLLOWING THE RAIN THIS WEEK. WINDS
WILL STAY OUT OF THE SOUTH TO SOUTHEAST...SO I WOULD NOT EXPECT TO
SEE RAPID DRYING. SOME OF THE MODEL GUIDANCE IS TRYING TO TAKE
TEMPERATURES JUST OVER 100 DEGREES...BUT THIS IS OVER THE AREA
THAT HAS RECEIVED THE HIGHER RAIN AMOUNTS. GIVEN THAT THE HIGHER
SOIL MOISTURE SHOULD HELP TO KEEP TEMPERATURES JUST A BIT
COOLER...I HAVE TENDED TEMPERATURES TOWARDS THE RAW GFS SOLUTION
WITH TEMPERATURES IN THE MID TO UPPER 90S.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 71 94 72 94 72 / 10 10 5 5 10
SAN ANGELO 69 93 71 94 71 / 10 10 5 10 10
JUNCTION 69 93 70 93 71 / 10 10 10 10 20
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
25
AREA FORECAST DISCUSSION
NWS SPOKANE WA
420 AM PDT Thu Jul 18 2013
.SYNOPSIS...
A prolonged period of dry weather is expected over the Inland
Northwest. No precipitation is anticipated for at least the next
seven days. Temperatures will be seasonably warm this weekend into
next week.
&&
.DISCUSSION...
Thursday through Friday night: A low amplitude ridge of high
pressure will be over the Inland NW to end the work week promoting
mostly clear skies and above normal warmth. Temperatures in
general will be warming into the 90`s for most valleys with light,
terrain driven winds. A broad upper-level low extending west from
central Canada will prevent the jet stream from migrating much
further north then the WA/BC border. This will keep a pool of
instability over southern BC...and perhaps into the extreme
northern mountains of WA. The threat is low but does exist and NAM
continues to indicate enough surface based instability over the
Pasayten Wilderness with the 00z model suite to support a stray
thunderstorm. Given its bias for placing instability over this
area...we have kept thunder mention out of the forecast but will
do another analysis in the morning to see how models and HRRR are
handling the boundary layer moisture with the idea that we may
need to include an isolated threat. /sb
Saturday through Monday: The biggest change to the forecast for
the weekend was to lower temperatures a few degrees. A couple of
days ago, the medium range models were suggesting a stronger upper
ridge for Saturday and Sunday. They have now trended toward a
flatter 500mb flow pattern. Afternoon temperatures Saturday
through Monday will still be above average, but not as hot as
previously thought. The air mass will be exceedingly dry. Model
cross sections for the weekend into Monday show very little chance
for clouds. The dry westerly flow Saturday and Sunday will likely
cause surface dewpoints to plunge into the 20s and low 30s. Some
of the driest air we have experienced this summer. The warm and
dry conditions will continue to cure the fuels in the higher
elevations bringing our region into the heart of the wildfire
season. /GKoch
Tuesday through Thursday: Models seem to initialize this period
rather well with a low pressure system off of the northern BC
coast and zonal flow coming around the low and into our region.
With the low having a cooler source region for moisture models
are not showing any significant chance of precipitation at this
time. The feature to watch will be the movement of the mentioned
low over the latter part of the week. The Euro and GEM both have
it moving towards land that would allow for increased winds
earlier whereas the GFS holds off on that movement and slowly
moves it down the BC coast which would bring winds to our
region...but at a later time. Depending on the track will also
determine if precip chances need updated with the associated
moisture and cold pool interactions that would likely take place.
This low will be an important feature to keep an eye on as it
could play a large role in the winds and precip chances for our
area. Stronger winds coupled with the forecasted low RH values
could lead to fire weather concerns and potentially highlights.
With this being in the far extended I leaned toward the more
consistent model in the GFS that would promote the zonal flow for
a longer period. Temperatures look to hold steady in the mid 80s
and low 90s for most making for pleasant conditions in the middle
part of next week. /Fliehman
&&
.AVIATION...
12Z TAFS: VFR conditions are expected through 12z Friday. A few
cumulus buildups are possible along the immediate Canadian border
...otherwise skies are expected to remain generally clear with light
terrain driven winds. /sb
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 89 60 92 62 91 59 / 0 0 0 0 0 0
Coeur d`Alene 90 55 91 57 90 56 / 0 0 0 0 0 0
Pullman 88 47 90 49 90 51 / 0 0 0 0 0 0
Lewiston 95 61 98 63 97 63 / 0 0 0 0 0 0
Colville 92 54 93 56 94 55 / 0 0 0 0 0 0
Sandpoint 87 50 88 52 89 51 / 0 0 0 0 0 0
Kellogg 87 55 90 57 89 56 / 0 0 0 0 0 0
Moses Lake 94 57 97 59 97 60 / 0 0 0 0 0 0
Wenatchee 93 65 95 67 95 62 / 0 0 0 0 0 0
Omak 94 55 97 57 96 59 / 0 0 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
230 AM PDT Thu Jul 18 2013
.SYNOPSIS...
A prolonged period of dry weather is expected over the Inland
Northwest. No precipitation is anticipated for at least the next
seven days. Temperatures will be seasonably warm this weekend into
next week.
&&
.DISCUSSION...
Thursday through Friday night: A low amplitude ridge of high
pressure will be over the Inland NW to end the work week promoting
mostly clear skies and above normal warmth. Temperatures in
general will be warming into the 90`s for most valleys with light,
terrain driven winds. A broad upper-level low extending west from
central Canada will prevent the jet stream from migrating much
further north then the WA/BC border. This will keep a pool of
instability over southern BC...and perhaps into the extreme
northern mountains of WA. The threat is low but does exist and NAM
continues to indicate enough surface based instability over the
Pasayten Wilderness with the 00z model suite to support a stray
thunderstorm. Given its bias for placing instability over this
area...we have kept thunder mention out of the forecast but will
do another analysis in the morning to see how models and HRRR are
handling the boundary layer moisture with the idea that we may
need to include an isolated threat. /sb
Saturday through Monday: The biggest change to the forecast for
the weekend was to lower temperatures a few degrees. A couple of
days ago, the medium range models were suggesting a stronger upper
ridge for Saturday and Sunday. They have now trended toward a
flatter 500mb flow pattern. Afternoon temperatures Saturday
through Monday will still be above average, but not as hot as
previously thought. The air mass will be exceedingly dry. Model
cross sections for the weekend into Monday show very little chance
for clouds. The dry westerly flow Saturday and Sunday will likely
cause surface dewpoints to plunge into the 20s and low 30s. Some
of the driest air we have experienced this summer. The warm and
dry conditions will continue to cure the fuels in the higher
elevations bringing our region into the heart of the wildfire
season. /GKoch
Tuesday through Thursday: Models seem to initialize this period
rather well with a low pressure system off of the northern BC
coast and zonal flow coming around the low and into our region.
With the low having a cooler source region for moisture models
are not showing any significant chance of precipitation at this
time. The feature to watch will be the movement of the mentioned
low over the latter part of the week. The Euro and GEM both have
it moving towards land that would allow for increased winds
earlier whereas the GFS holds off on that movement and slowly
moves it down the BC coast which would bring winds to our
region...but at a later time. Depending on the track will also
determine if precip chances need updated with the associated
moisture and cold pool interactions that would likely take place.
This low will be an important feature to keep an eye on as it
could play a large role in the winds and precip chances for our
area. Stronger winds coupled with the forecasted low RH values
could lead to fire weather concerns and potentially highlights.
With this being in the far extended I leaned toward the more
consistent model in the GFS that would promote the zonal flow for
a longer period. Temperatures look to hold steady in the mid 80s
and low 90s for most making for pleasant conditions in the middle
part of next week. /Fliehman
&&
.AVIATION...
06Z TAFS: VFR conditions are expected through 06z Friday. Other
than flat cumulus over the mountains near the Canadian border
Thursday afternoon...skies are expected to remain generally clear
except for a few mid level accus clouds over Northeast Washington
and North Idaho tonight. JW
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 89 60 92 62 91 59 / 0 0 0 0 0 0
Coeur d`Alene 90 55 91 57 90 56 / 0 0 0 0 0 0
Pullman 88 47 90 49 90 51 / 0 0 0 0 0 0
Lewiston 95 61 98 63 97 63 / 0 0 0 0 0 0
Colville 92 54 93 56 94 55 / 0 0 0 0 0 0
Sandpoint 87 50 88 52 89 51 / 0 0 0 0 0 0
Kellogg 87 55 90 57 89 56 / 0 0 0 0 0 0
Moses Lake 94 57 97 59 97 60 / 0 0 0 0 0 0
Wenatchee 93 65 95 67 95 62 / 0 0 0 0 0 0
Omak 94 55 97 57 96 59 / 0 0 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1050 PM CDT FRI JUL 19 2013
.UPDATED...
ISSUED AT 1050 PM CDT FRI JUL 19 2013
SMALL AREA OF SHOWERS/STORMS MAKING ITS WAY SOUTHEAST ACROSS CENTRAL
MN. SEEMS SPARKED BY A PIECE OF UPPER LEVEL ENERGY...MARRIED WITH
SOME 850 MB MOISTURE TRANSPORT AND WEAK INSTABILTY. RAP WOULD HANG
ONTO THIS FORCING AS IT CROSSES THROUGH WESTERN WI...SUGGESTING THE
PCPN WILL PERSIST. LATEST HRRR/NAM12 HAS THIS PCPN...BUT DIE IT OFF
BEFORE IT GETS INTO THE FORECAST AREA. GOING SIDE WITH THE FORCING
FOR NOW AND ADD SOME SMALL POPS FOR PARTS OF THE AREA...MOSTLY IN
THE I-94 CORRIDOR.
.SHORT TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 315 PM CDT FRI JUL 19 2013
SURFACE MAP THIS AFTERNOON SHOWS A COLD FRONT MAKING ITS WAY
SOUTHEAST ACROSS THE AREA...EXTENDING FROM EASTERN UPPER MI THROUGH
SOUTHWEST WI AND NORTHEAST IA. SO FAR...ALL IS WELL AND QUIET ALONG
AND AHEAD OF THE FRONT WITH ONLY A FEW SHRA/TS PUSHING EAST ACROSS
EAST CENTRAL IA AND SOUTHEAST WI. OTHERWISE...TEMPERATURES ACROSS
THE FORECAST AREA THIS AFTERNOON RANGED FROM THE MIDDLE 80S TO THE
LOWER 90S. DEWPOINTS ALSO SHOWING A DOWNWARD TREND AS DRIER AIR
FILTERS IN BEHIND THE DEPARTING FRONT. HEAT INDICES THIS AFTERNOON
RANGED FROM THE MIDDLE 80S ACROSS NORTH CENTRAL WI...TO THE MIDDLE
90S ACROSS FAR SOUTHWEST WI...A LITTLE MORE BEARABLE THAN THE LAST
COUPLE OF DAYS. WILL LET REMAINING HEAT HEADLINES EXPIRE AT 7PM AS A
RESULT.
FOR TONIGHT...DRIER AND COOLER AIR WILL CONTINUE TO FILTER INTO THE
AREA. WILL BE WATCHING A WEAK MID-LEVEL TROUGH IN NORTHWEST FLOW
MOVING THROUGH THE DAKOTAS INTO MN. RADAR MOSAIC WAS SHOWING SOME
SHRA/TS ACTIVITY ASSOCIATED WITH THIS WAVE ACROSS NORTHERN ND.
MODELS DRY THIS WAVE OUT AS IT DAMPENS/MOVES SOUTHEAST TOWARD THE
AREA TONIGHT. THIS MAKES SENSE WITH WEAK FORCING/LOSS OF SURFACE
HEATING. WILL GO DRY FOR NOW AND EXPECTED JUST SOME PERIODIC
SCATTERED MID-CLOUD. OTHERWISE...PLAN ON MUCH MORE COMFORTABLE LOWS
IN THE UPPER 50S TO MIDDLE 60S.
FOR SATURDAY...WILL BE WATCHING ANOTHER MID-LEVEL TROUGH OF LOW
PRESSURE MAKING ITS WAY OUT OF THE PLAINS TOWARD THE UPPER
MISSISSIPPI RIVER VALLEY REGION. PRETTY WEAK FORCING INDICATED BY
THE MODELS WITH THIS WAVE WITH MODEST AMOUNT OF LIFT/MOISTURE
TRANSPORT. FEEL THERE WILL BE AN INCREASE IN CLOUDS AT LEAST AND
THERE IS SOME SUPPORT FROM THE RIGHT ENTRANCE REGION OF THE 300MB
JET WHICH COULD ENHANCE THE LIFT A BIT...LEADING TO
ISOLATED/SCATTERED CONVECTION. NAM DOES INDICATE INCREASING 0-1ML
MUCAPE INT THE 1000-1500J/KG ACROSS PORTIONS OF NORTHEAST IA INTO
SOUTHWEST WI BY LATER IN THE AFTERNOON. BASED ON THE WEAK SIGNAL AND
CAPE VALUES...KEPT SLIGHT CHANCES GOING WITH A MENTION OF THUNDER.
WITH MORE CLOUD AND ISOLATED-SCATTERED CONVECTION...TEMPERATURES
WILL RESPOND ACCORDINGLY ONLY MAKING IT INTO THE 70S/LOWER 80S.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 315 PM CDT FRI JUL 19 2013
NORTHWEST FLOW ALOFT SEND ANOTHER BIT MORE VIGOROUS MID-LEVEL
SHORTWAVE TROUGH INT THE REGION SATURDAY NIGHT/SUNDAY FOR INCREASING
SHOWER/THUNDERSTORM CHANCES. IN FACT...SIGNAL HAS BEEN PRETTY
CONSISTENT FOR SHOWERS/THUNDER ON SUNDAY...SO WENT WITH LIKELY POPS
MAINLY ALONG/SOUTHWEST OF I-94.. HIGHEST CAPE VALUES FOR THUNDER
APPEARS TO BE CONFINED ALONG/WEST OF THE MISSISSIPPI RIVER ON THE
NOSE OF BETTER 850MB MOISTURE TRANSPORT. OTHERWISE...PLAN ON HIGHS
IN THE 70S GIVEN MOSTLY CLOUDY SKIES AND THE LIKELIHOOD OF RAIN. A
GOOD CHANCE OF SHOWERS AND THUNDERSTORMS LOOKS TO LINGER INTO SUNDAY
NIGHT AS THE WAVE WILL BE RELATIVELY SLOW-MOVING.
NORTHWEST FLOW ALOFT SENDS ANOTHER MID-LEVEL TROUGH/SURFACE COLD
FRONT INTO THE REGION MONDAY/MONDAY NIGHT FOR ANOTHER CHANCE OF
SHOWERS AND THUNDERSTORMS. HIGHS ON MONDAY ARE EXPECTED TO WARM INTO
THE 78-83 DEGREE RANGE AHEAD OF THE FRONT WITH INCREASING DEW POINTS
INTO THE 60S/LOWER 70S. WILL HAVE TO WATCH THIS FRONTAL TIMING
CLOSELY AS THE NAM BUILDS 0-1KM ML MUCAPE INTO THE 3500-4500J/KG
RANGE BY AFTERNOON WITH 0-3KM BULK SHEAR IN THE 25-35KT RANGE. COULD
BE LOOKING AT SOME SEVERE WEATHER POTENTIAL BASED ON THIS SIGNAL.
LINGERING SHOWERS AND THUNDERSTORMS ARE POSSIBLE MAINLY ACROSS
SOUTHEAST SECTIONS OF THE FORECAST AREA TUESDAY WITH COOLER CYCLONIC
FLOW ALOFT BEHIND THE FRONT.
LOOKS LIKE A DRY PERIOD FROM TUESDAY NIGHT THROUGH THURSDAY AS THE
GFS/ECMWF SHOW HIGH PRESSURE BUILDING INTO THE AREA. HIGHS WEDNESDAY
AND THURSDAY ARE EXPECTED TO TOP OFF IN THE MIDDLE 70S TO THE LOWER
80S.
SHOWER AND THUNDERSTORM CHANCES RE-ENTER THE PICTURE FOR THURSDAY
NIGHT INTO FRIDAY AS ANOTHER COLD FRONT DROPS INTO THE REGION FROM
THE NORTHERN PLAINS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1050 PM CDT FRI JUL 19 2013
SOME UPPER LEVEL FORCING...COUPLED WITH A BIT OF LOW LEVEL MOISTURE
CONVERGENCE/INSTABILTY...WAS SPARKING A SMALL AREA OF SHRA/TS OVER
CENTRAL MN. IT LOOKS LIKE THIS WILL HOLD TOGETHER FOR THE OVERNIGHT
HOURS...WORKING INTO WESTERN WI. BELIEVE THE PCPN WILL STAY NORTH OF
THE TAF SITES AT THIS MOMENT...SO WILL LEAVE ANY MENTION OUT OF THE
FORECAST.
GENERALLY VFR THOUGH THE DAY...BUT CLOUDS WILL BE ON THE INCREASE
FROM THE WEST THANKS TO ANOTHER UPPER LEVEL FEATURE. SOME SHRA/TS
ARE ALSO POSSIBLE...WHICH COULD IMPACT KRST. COVERAGE COULD BE MORE
SCATTERED THOUGH...AND CONFIDENCE ISN/T HIGH ENOUGH TO ADD SHRA OR
VCSH YET. SOMETHING TO MONITOR. CLOUDS WILL CONTINUE TO INCREASE AND
THICKEN FROM THE WEST SAT NIGHT...BUT LOOKS TO STAY VFR. RAIN
CHANCES WILL INCREASE FOR SUN/MON THANKS TO A FEW DIFFERENT WEATHER
TRIGGERS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1041 PM CDT FRI JUL 19 2013
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND SATURDAY
ISSUED AT 204 PM CDT FRI JUL 19 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A LINE OF
CLOUDS EXTENDING FROM A PRE-FRONTAL TROUGH FROM LOWER MICHIGAN TO
NEBRASKA...WHICH EXITED THE AREA EARLIER THIS MORNING. THE MAIN
FOCUS CENTERS AROUND A COLD FRONT WHICH EXTENDS FROM WAUSAUKEE TO
MINNEAPOLIS. A LINE OF BUBBLY CU CONTINUES TO FIRE ALONG THE
FRONT...THOUGH CONVECTION IS WIDELY SCT AT BEST. DID HAVE ONE
STRONG STORM DEVELOP OVER THE SOUTHERN U.P. EARLIER THIS
AFTERNOON...BUT THE OTHER STORMS HAVE BEEN GARDEN VARIETY. GUSTY
WEST WINDS HAVE HELPED MIX DOWN DRIER AIR ALOFT OVER NORTH-CENTRAL
AND CENTRAL WISCONSIN...WHICH HAS KEPT THE INSTABILITY IN CHECK OVER
THESE AREAS. DEWPOINTS REMAIN IN THE LOW 70S FROM THE SOUTHERN FOX
VALLEY TO THE WEST SHORE OF THE BAY OF GREEN BAY WHERE ML CAPES ARE
UPWARDS OF 1.6K J/KG. DEWPOINTS HAVE BEEN FALLING JUST UPSTREAM OF
THE FOX VALLEY AT SHAWANO AND WAUPACA...SO THINK THIS TREND WILL
MOVE TO LOCATIONS FURTHER EAST. AS RESULT...THINK CHANCES OF SEVERE
STORMS DEVELOPING IS RELATIVELY LOW AND WILL JUST CARRY A SLIGHT
CHANCE OF STORMS FOR THE REST OF THE AFTERNOON. AS FOR THE HEAT
ADVISORY...SOME LOCATIONS FLIRTING WITH CRITERIA...BUT IN
GENERAL...HEAT INDEX READINGS ARE BELOW 95F. WITH DEWPOINTS FALLING
DUE TO MIXING...WILL CANCEL THE ADVISORY WITH THE AFTERNOON FORECAST
PACKAGE.
TONIGHT...ISOLATED SHOWERS AND THUNDERSTORMS WILL CONTINUE FOR THE
FIRST COUPLE HOURS OF THE EVENING. THE THREAT OF PRECIP WILL
DIMINISH QUICKLY BY MID-EVENING...AND DRIER AIR WILL GRADUALLY
FILTER SOUTHEAST ACROSS THE REGION. THE MAIN PUSH OF COOLER AND
DRIER AIR WILL NOT ARRIVE UNTIL LATE TONIGHT WHEN A SECONDARY FRONT
SHIFTS SOUTH ACROSS THE NORTHERN THIRD OF THE STATE. UNTIL THAT
FRONT ARRIVES...THINK WILL SEE MOSTLY CLEAR TO PARTLY CLOUDY
CONDITIONS. LOWS RANGING FROM THE MIDDLE 50S NORTH TO THE MIDDLE
60S SOUTH.
SATURDAY...THE SECONDARY COLD FRONT WILL CONTINUE MOVE SOUTH ACROSS
CENTRAL WISCONSIN EARLY IN THE PERIOD AND THEN SETTLE OVER THE
SOUTHERN GREAT LAKES IN THE AFTERNOON. RIGHT REAR QUAD OF JET STREAK WILL
SWING FROM WEST-CENTRAL WISCONSIN TO SOUTHEAST WISCONSIN BUT THE
DEEPER MOISTURE WILL BE TIED UP ALONG THE COLD FRONT SO CENTRAL
WISCONSIN MAY JUST SEE A LITTLE MORE CU THAT THE REST OF THE
REGION. OTHERWISE...LIGHT NORTH WINDS WILL USHER IN DEWPOINTS IN
THE MID 40S TO MID 50S...WITH HIGHS MAINLY RANGING THROUGH THE 70S.
.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY
ISSUED AT 204 PM CDT FRI JUL 19 2013
UPPER PATTERN THIS PERIOD CHARACTERIZED BY MEAN TROF IN THE EAST
WITH RIDGE OVER THE WEST. RIDGE EXPECTED TO BUILD SOME OVER
ROCKIES LATER IN PERIOD. TIMING ISSUES LATER PERIODS CONTINUE WITH
MODELS...THOUGH TREND IS TOWARD HIGHEST PROBABILITY OF PCPN
MON/MON NIGHT. OP GFS COOLER AT END OF PERIOD THAN THAT SUGGESTED
BY 00Z ECMWF...THOUGH CURRENT ENSEMBLES FROM BOTH GFS AND ECMWF
TREND CLOSER TO GFS SOLUTION. HAVE STAYED WITH BLEND OF MODELS FOR
LATER PERIODS.
IN NEAR TERM...SFC HIGH TO SHIFT EAST WITH WARM FRONT MOVING INTO
SOUTHWEST WI SAT NIGHT. GIVEN LINGERING DRY AIR MASS WILL STAY
WITH INHERITED DRY FORECAST. WAA REGIME CONTINUES SUN INTO MONDAY
AHEAD OF FRONT EXPECTED TO MOVE THROUGH LATER MONDAY. MUCH OF GULF
MOISTURE TIED TO FRONT TO SOUTH OF AREA. MODELS NOT SHOWING MUCH
IN THE WAY OF INSTABILITY...SOME WEAK ELEVATED INSTABILITY
PRESENT. WENT MORE WITH SHOWERS...ISOLATED THUNDER AT BEST.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1041 PM CDT FRI JUL 19 2013
WHILE ONE COLD FRONT DEPARTS FAR SOUTHEAST WISCONSIN
LATE THIS FRIDAY EVENING...A SECONDARY COLD FRONT WILL TRACK OVER
THE STATE ON SATURDAY. AN ISOLATED SHOWER MAY BRUSH OVER PARTS OF
CENTRAL WISCONSIN ALONG THIS FRONT DURING PASSAGE ON SATURDAY.
OTHERWISE MAINLY VFR CONDITIONS EXPECTED THROUGH SATURDAY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......TE
AVIATION.......TDH
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
853 PM CDT FRI JUL 19 2013
.UPDATE...
THE ACTIVITY THIS EVENING ENDED UP FOCUSING OUT AHEAD OF THE
FRONT...IN THE DEEPER MOISTURE DEPICTED BY WATER VAPOR IMAGERY.
THIS ZONE WAS ACROSS NORTHERN ILLINOIS...BACK SOUTHWEST INTO
EASTERN IOWA. THE FRONT JUST NEVER HAD A CHANCE WITH THE STORMS...
AS TOO MUCH DRY AIR ENTRAINMENT LIMITED DEVELOPMENT. THE REMAINDER
OF THE NIGHT WILL BE QUIET WITH MOSTLY CLEAR SKIES.
DRIER AIR IS MOVING IN...BUT MAY STALL A BIT AS WINDS DIMINISH
OVERNIGHT. DEWPOINTS SHOULD DROP INTO THE UPPER 50S TO MID 60S
OVERNIGHT...THEN DROP FURTHER ON SATURDAY.
&&
.AVIATION/06Z TAFS/...VFR THROUGH THE PERIOD. WE COULD SEE SOME
PATCHY MVFR VSBYS DUE TO FOG AS WE APPROACH SUNRISE ON SATURDAY.
BUT THAT WILL MIX OUT QUICKLY AFTER SUNRISE. WINDS WILL BE 10
KNOTS OR LESS.
&&
.PREV DISCUSSION... /ISSUED 330 PM CDT FRI JUL 19 2013/
SHORT TERM...
LATE THIS AFTERNOON...TONIGHT AND SATURDAY...FORECAST CONFIDENCE IS
MEDIUM TO HIGH.
MAIN ISSUE WILL BE AREAL COVERAGE OF SHOWERS AND THUNDERSTORMS AS
COLD FRONT SLIDES SOUTHEAST THROUGH THE AREA THROUGH EARLY THIS
EVENING. CUMULUS LINE FORMING ALONG FRONT TO THE NORTHWEST OF THE
FORECAST AREA. UPWARD VERTICAL MOTION IS WEAK TO MODEST WITH FRONT
AS IT PASSES THROUGH THE AREA...WITH WEAK TO MODEST 500MB VORTICITY
MAXIMUM TRAILING THE FRONT.
CAP ALMOST MIXED OUT IN SOUTHEAST COUNTIES WITH LOWER TO MID 90S
TEMPERATURES...WITH SLIGHTLY COOLER TEMPERATURES ALLOWING FOR A BIT
MORE CAPPING TO THE NORTHWEST. LATEST HRRR/WRF 4KM WITH LAPS AGREE
ON A BROKEN LINE OF SHOWERS AND THUNDERSTORMS MOVING THROUGH THE
AREA WITH THE FRONT. BEST CHANCES PROBABLY WILL BE IN THE FAR EAST
AND OVER LAKE MICHIGAN...AS FRONT INTERACTS WITH COOL LAKE AIRMASS
AND RESULTS IN ENHANCED UPWARD VERTICAL MOTION.
WENT WITH SCATTERED POPS IN FORECAST THROUGH EARLY EVENING FROM
NORTHWEST TO SOUTHEAST ACROSS THE AREA...AS THERE IS SOME
UNCERTAINTY WITH THE AREAL COVERAGE GIVEN THE WEAK TO MODEST UPWARD
VERTICAL MOTION.
SPC HAS MAINLY THE SOUTHEAST HALF OF THE AREA IN SLIGHT RISK FOR
SEVERE STORMS THROUGH EARLY EVENING. RAP AREA FORECAST SOUNDINGS
INDICATE AROUND 2500 J/KG MEAN LAYER CAPE WITH AROUND 30 KNOTS OF 0
TO 6 KM SHEAR AND FAIRLY HIGH PRECIPITABLE WATER VALUES. THIS SHOULD
ALLOW FOR SOME STRONG TO SEVERE STORMS TO DEVELOP. DAMAGING WINDS
AND LARGE HAIL WOULD BE THE MAIN HAZARDS.
KEPT HEAT ADVISORY GOING UNTIL 00Z SATURDAY ACROSS THE
AREA...DESPITE MIXY CONDITIONS KEEPING DEW POINTS IN THE 60S IN
PORTIONS OF THE AREA. HEAT INDEX VALUES WILL STILL BE IN THE 95 TO
102 RANGE.
COLD AIR ADVECTION THEN BRINGS COOLER AND DRIER AIRMASS INTO THE
REGION BEHIND FRONT FROM MID EVENING THROUGH SATURDAY...AS HIGH
PRESSURE BUILDS INTO THE REGION FROM THE NORTHWEST.
BACKDOOR COLD FRONT DOES SLIDE SOUTHWARD THROUGH THE AREA
SATURDAY...FIRST DOWN THE LAKESHORE THEN IN THE WEST LATER IN THE
DAY. NORTHEAST WINDS AFTER THE FRONTAL PASSAGE WILL BRING COOLER
TEMPERATURES...ESPECIALLY NEAR THE LAKE. KEPT DRY FORECAST AS
AIRMASS IS FAIRLY DRY DESPITE WEAK INSTABILITY IN FORECAST
SOUNDINGS.
SATURDAY NIGHT THROUGH TUESDAY...FORECAST CONFIDENCE MEDIUM
WEAK VORTICITY MAXIMUMS WITHIN NW FLOW ALOFT WILL MOVE ACROSS THE
REGION DURING THIS PERIOD. A SLIGHTLY MORE ORGANIZED SHORTWAVE
TROUGH WILL PASS THROUGH IA...IL...AND SRN WI FOR SUNDAY
AFTERNOON THROUGH THE NIGHT BUT LOOKS THE MOST ORGANIZED TO THE
SOUTH. PWS HOWEVER COULD INCREASE TO 1.5 INCHES WITH THIS FEATURE.
MAINTAINING CHANCE POPS FOR THIS BUT IF UPPER WAVE BECOMES
STRONGER WITH GIVEN MOISTURE...THEN RAIN COVERAGE AND INTENSITY
WOULD BE HIGHER. WITH MORE HUMID CONDITIONS RETURNING AND SCT-BKN
CLOUD COVER...KEPT MILD LOW TEMPS FOR THIS PERIOD. ONSHORE FLOW
WILL KEEP FAR ERN WI RELATIVELY COOL FOR SAT BUT INLAND TEMPS MORE
CHALLENGING. DID ACCOUNT FOR SOME SUNSHINE IN HIGHS FOR SAT.
SUBSIDENCE FROM DEPARTING SHORTWAVE TROUGH FOR MON SHOULD RESULT
IN MORE SUNSHINE. IN ADDITION...SSWLY WINDS AND WEAK WARM ADVECTION
AHEAD OF LOW PRESSURE TRACKING ACROSS SRN CANADA SHOULD ALSO HELP
BOOST HIGH TEMPS INTO THE MID 80S AWAY FROM THE LAKE. ONLY A
SLIGHT CHANCE OF TSTORMS IS FORECAST TO ACCOUNT FOR SLOWER
SHORTWAVE TROUGH MOVEMENT OR A FASTER MOVEMENT OF THE COLD FRONT
THAT EXTENDS FROM THE CANADIAN LOW. LOW POPS ARE THEN FORECAST FOR
THE COOL FROPA MON NT AND TUE.
LONG TERM...
WEDNESDAY THROUGH FRIDAY...FORECAST CONFIDENCE MEDIUM
EXTENDED MODELS DUE SHOW A MORE ORGANIZED SFC HIGH PRESSURE AREA
TO COME INTO THE GREAT LAKES REGION FOR WED AND THU AND POSSIBLY
EXTENDING THROUGH FRI. WENT DRY WITH THE EXCEPTION OF THE FAR WRN
CWA FOR FRI. PLEASANT WITH NEAR NORMAL TEMPS AND HUMIDITY EXPECTED.
AVIATION/00Z TAFS/...VFR CONDITIONS ARE EXPECTED ACROSS TAF SITES
TONIGHT AND SATURDAY. GUSTY SOUTHWEST TO WEST WINDS ARE EXPECTED
UNTIL SUNSET...WITH FREQUENT GUSTS IN THE 20 TO 25 KNOT RANGE. SOME
DIURNAL CUMULUS WILL DEVELOP AS MID LEVEL CLOUDS MOVE THROUGH AND
EAST OF THE AREA.
SCATTERED SHOWERS AND STORMS ARE EXPECTED WITH THE COLD FRONTAL
PASSAGE LATER THIS AFTERNOON...ENDING EARLY THIS EVENING AS FRONT
MOVES OUT OF THE AREA. LEFT VICINITY THUNDER WORDING IN TAFS TO
ACCOUNT FOR THIS...WITH BRIEF MVFR VISIBILITIES AND GUSTY WINDS
POSSIBLE IN ANY STORMS. AREAL COVERAGE IS UNCERTAIN...SO COULD END
UP BEING DRY AT TAF SITES.
WINDS WILL SHIFT TO THE NORTHWEST BEHIND THE FRONT BY MID
EVENING...WITH SKIES CLEARING OUT TONIGHT WITH COOLER AND DRIER
AIRMASS MOVING IN. WINDS WILL SHIFT NORTH AND THEN NORTHEAST BY
SATURDAY AFTERNOON...AS BACKDOOR COLD FRONT MOVES SOUTHWARD THROUGH
THE AREA. MOSTLY CLEAR SKIES ARE EXPECTED SATURDAY AT THE EASTERN
SITES...WITH SOME DIURNAL CUMULUS AT MADISON DURING THE AFTERNOON.
MARINE...SMALL CRAFT ADVISORY WILL CONTINUE UNTIL 00Z SATURDAY
ACROSS THE NEARSHORE WATERS OF LAKE MICHIGAN. TIGHT PRESSURE
GRADIENT AND MIXING WITH DAYTIME HEATING WILL CONTINUE TO BRING
GUSTY SOUTHWEST TO WEST WINDS ACROSS THIS AREA THROUGH THE REST OF
THE DAY. GUSTS IN THE MID 20 KNOT RANGE ARE EXPECTED AT TIMES.
OFFSHORE FLOW WILL KEEP ANY HIGH WAVES OVER THE OPEN WATERS. THE
GUSTS WILL SUBSIDE BY EVENING...WITH A WEAKENING PRESSURE GRADIENT
WITH THE PASSING COLD FRONT.
BACKDOOR COLD FRONT WILL PUSH SOUTHWARD ACROSS THE NEARSHORE WATERS
OF LAKE MICHIGAN SATURDAY MORNING...WITH A QUICK WIND SHIFT TO THE
NORTHEAST BEHIND IT. WINDS MAY BE GUSTING UP TO 15 KNOTS OR SO FOR
AN HOUR OR TWO AFTER THE FRONTAL PASSAGE...THEN REMAIN IN THE 10 TO
15 KNOT RANGE THROUGH THE REST OF THE DAY.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...DAVIS
TONIGHT/SATURDAY AND AVIATION/MARINE...WOOD
SATURDAY NIGHT THROUGH FRIDAY...GEHRING
AREA FORECAST DISCUSSION
NWS TUCSON AZ
905 PM MST FRI JUL 19 2013
.SYNOPSIS...LOW PRESSURE OVER THE GULF OF CALIFORNIA WILL PROVIDE A
MOIST EAST TO SOUTHEAST FLOW THIS WEEKEND. THIS FLOW WILL INCREASE
CHANCES FOR SHOWERS AND THUNDERSTORMS WITH POTENTIALLY HEAVY
RAINFALL. THEREAFTER...A MORE NORMAL CYCLE OF SCATTERED AFTERNOON
AND EVENING THUNDERSTORMS WILL RETURN FOR MUCH OF NEXT WEEK.
&&
.DISCUSSION...ISOLATED SHOWERS ONGOING ACROSS ERN SANTA CRUZ AND
SWRN COCHISE COUNTIES SOUTH OF TUCSON AS WELL AS ACROSS NRN GREENLEE/
NRN GRAHAM COUNTIES NE OF TUCSON. DRY CONDITIONS PREVAILED ELSEWHERE
ACROSS SE AZ AT THIS TIME. CLOUD TOPS ASSOCIATED WITH THE MCS ACROSS
NERN SONORA WERE WARMING DURING THE PAST 1-2 HOURS.
THE PAST 3 HOURS OF RUC HRRR SOLUTIONS HAVE YIELDED FAIRLY MARKEDLY
DIFFERENT RESULTS REGARDING PRECIP POTENTIAL THE REST OF TONIGHT. 2
SOLUTIONS YIELDED PRECIP TO REDEVELOP AROUND MIDNIGHT JUST NORTH AND
WEST OF TUCSON AND CONTINUE TO MOVE WEST ACROSS THE TOHONO O`ODHAM
NATION. ONE SOLUTION YIELDED VERY LITTLE PRECIP THE REST OF TONIGHT.
BASED ON THE 20/00Z UPPER PLOTS...AM INCLINED TO BELIEVE THAT
ISOLATED TO PERHAPS SCATTERED SHOWERS AND A FEW THUNDERSTORMS MAY
OCCUR THRU ABOUT 20/09Z DUE TO DIFFLUENCE ALOFT. RAINFALL AMOUNTS
SHOULD BE QUITE LIGHT AS PER EACH RUC HRRR SOLUTION. THUS...NO
CHANGES OF SIGNIFICANCE FOR THE INHERITED GRIDDED DATA POP FIELDS
FOR THE REST OF TONIGHT.
MIN TEMPS LATER TONIGHT ARE FORECAST TO BE WITHIN A DEGREE-OR-TWO OF
NORMAL. PLEASE REFER TO THE PREVIOUS DISCUSSION SECTION BELOW FOR
ADDITIONAL DETAIL.
&&
.PREV DISCUSSION /155 PM MST FRI JUL 19 2013/...WITH THE LOW
PRESSURE OVER SONORA AND ATTENDANT CLOUDS DRIFTING ONLY SLOWLY WEST
THEN UP THE BAJA/GULF AREA THE NEXT FEW DAYS...MORNING CLOUDS COULD
CONTINUE TO HINDER ATMOSPHERIC HEATING...BUT IF THIS HINDRANCE IS
OVERCOME...STORMS THAT DEVELOP COULD PRODUCE HEAVY RAIN. MODEL
DEPICTIONS OF THE LOW TRACK AND THE MOISTURE FIELDS TEND TO FAVOR
MUCH OF THE AREA STILL BEING AFFECTED BY CLOUD COVER AND ONCE AGAIN
LIMITING HEATING...WHEREAS SUNDAY WE MAY WARM UP QUICKER AND BE ABLE
TO GENERATE MORE THUNDERSTORM COVERAGE.
FOR NEXT WEEK...A SECONDARY AREA OF LOW PRESSURE WILL MOVE ACROSS
NRN MEXICO...POSSIBLY INFLUENCING OUR WEATHER ONCE AGAIN AND KEEPING
THE CHANCES FOR THUNDERSTORMS AT OR ABOVE CLIMATOLOGICAL NORMALS...KD
&&
.AVIATION...SCATTERED -SHRA AND ISOLATED -TSRA MOSTLY ENDING AROUND
20/09Z. SCATTERED TO NUMEROUS SHRA/TSRA TO OCCUR SATURDAY AFTERNOON
AND CONTINUE INTO SATURDAY EVENING. MVFR CONDITIONS WITH BRIEF WIND
GUSTS TO AROUND 45 KTS WITH THE STRONGER TSRA. OTHERWISE...CLOUD
DECKS GENERALLY 5-9K FT AGL AND SURFACE WIND MAINLY LESS THAN 10 KTS
THRU SATURDAY EVENING OR 21/06Z. AVIATION DISCUSSION NOT UPDATED FOR
TAF AMENDMENTS.
&&
.FIRE WEATHER...UPPER LOW OVER SONORA MEXICO WILL MAINTAIN A MOIST
EASTERLY FLOW ACROSS SOUTHERN ARIZONA THROUGH THE WEEKEND. THE
COMBINATION OF THE UPPER LOW AND ABUNDANT ATMOSPHERIC MOISTURE WILL
BRING ABOUT PLENTY OF CONVECTION THAT WILL BE ABLE TO OCCUR ANYTIME
WITH A FOCUS DURING THE AFTERNOON AND EVENING HOURS. THE STRONGER
THUNDERSTORMS WILL BE CAPABLE OF PRODUCING HEAVY DOWNPOURS AS WELL
AS GUSTY AND ERRATIC WINDS. RELATIVE HUMIDITIES WILL REMAIN MOIST
WITH THE NORMAL DIURNAL WIND PATTERNS DISRUPTED AT TIMES THIS
WEEKEND BY CONVECTION. THE SHOWERS AND THUNDERSTORMS WILL BECOME
LESS NUMEROUS AND MORE DIURNAL IN NATURE NEXT WEEK AS THE LOW MOVES
FURTHER WEST AND THE AIR MASS BECOMES A BIT DRIER.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
DISCUSSION/AVIATION...FRANCIS
PREVIOUS DISCUSSION...DROZD
FIRE WEATHER...CERNIGLIA
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
255 AM PDT SAT JUL 20 2013
.SYNOPSIS...
A MOIST EAST FLOW PATTERN WILL BRING INCREASING MONSOONAL MOISTURE
WITH PERIODS OF SHOWERS AND ISOLATED THUNDERSTORMS THROUGH
MONDAY...DECREASING ON TUESDAY. FLASH FLOODING IS POSSIBLE IN RECENT
BURN AREAS. WARMER AND DRIER FOR THE LATTER HALF OF NEXT WEEK WITH
SOUTHWEST FLOW ALOFT.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
.SHORT TERM (TODAY THROUGH MONDAY)...
IN THE NEAR TERM...THE MESOSCALE CONVECTIVE SYSTEM OVER SAN
BERNARDINO COUNTY WILL CONTINUE TO MOVE WESTWARD AND SLOWLY WEAKEN
BASED ON SATELLITE AND RADAR TRENDS. MODELS HAVE TYPICALLY BEEN OF
LIMITED VALUE IN HANDLING THIS SYSTEM WITH THE 02Z HRRR THE LEAST
CLUELESS OF THE BUNCH. IT AT LEAST SHOWED A CIRCULATION CENTER AND
MOSTLY ASSOCIATED SHOWERS TRANSLATING WESTWARD ACROSS SOUTHERN
CALIFORNIA THIS MORNING. THE MODELS HAVE ALSO BEEN LESS THAN HELPFUL
WITH REGARD TO THE MORE RECENT CONVECTION IN SOUTHWEST ARIZONA AND
THE FAR EASTERN DESERTS OF SOUTHERN CALIFORNIA. THAT CONVECTION
CONTINUES TO MOVE SLOWLY WESTWARD AND COULD AT LEAST PUSH SOME
OUTFLOW ACROSS THE LOWER DESERTS OF SOUTHERN CALIFORNIA.
HIGH PRESSURE OVER NEVADA WILL DIRECT AN INCREASINGLY MOIST
MONSOONAL AIR MASS INTO SOUTHWEST CALIFORNIA THROUGH SUNDAY.
PRECIPITABLE WATER VALUES A LITTLE OVER ONE INCH FRIDAY AFTERNOON
WILL INCREASE TO 1.4 INCHES THIS AFTERNOON AND 1.7 INCHES SUNDAY
AFTERNOON. A DRYING TREND WILL BEGIN MONDAY. THIS WILL BRING PERIODS
OF SHOWERS AND ISOLATED THUNDERSTORMS INTO MONDAY. SOME
PRECIPITATION COULD MOVE WEST OF THE MOUNTAINS TONIGHT THROUGH
SUNDAY NIGHT. THE ABUNDANT MID AND HIGH LEVEL MOISTURE WILL LIMIT
SURFACE HEATING AND THE POTENTIAL FOR STRONGER AFTERNOON
THUNDERSTORMS SOMEWHAT THROUGH SUNDAY. HOWEVER...GIVEN THE
INCREASING MOISTURE CONTENT...THUNDERSTORMS THAT DO DEVELOP COULD
PRODUCE LOCALLY HEAVY RAINFALL. FLASH FLOOD GUIDANCE THRESHOLDS FOR
NEW BURN AREAS ARE THREE TENTHS OF AN INCH OF RAINFALL IN 30
MINUTES...SOMETHING THAT WOULD BE POSSIBLE WITH ANY OF THE
THUNDERSTORMS. HENCE...A FLASH FLOOD WATCH FOR THE BURN AREAS HAS
BEEN ISSUED THROUGH SUNDAY EVENING.
AS THE HIGHER LEVEL MOISTURE BEGINS TO DECREASE MONDAY WITH THE MID
LEVEL MOISTURE REMAINING IN PLACE...THERE WOULD BE GREATER POTENTIAL
FOR DEVELOPMENT OF STRONGER THUNDERSTORMS MONDAY AFTERNOON WITH
GREATER POTENTIAL FOR FLASH FLOODING IN THE MOUNTAINS AND
DESERTS...NOT JUST IN RECENT BURN AREAS.
THE INCREASING CLOUD COVER WILL BRING COOLING FOR INLAND AREAS INTO
SUNDAY WITH SLOW WARMING FOR MONDAY. THE MARINE LAYER AND ONSHORE
LOWER LEVEL FLOW WILL CONTINUE TO KEEP COASTAL AREAS COOLER WITH
AREAS OF NIGHT AND MORNING LOW CLOUDS AND FOG.
&&
.LONG TERM (TUESDAY THROUGH FRIDAY)...
A WEAK TROUGH OF LOW PRESSURE NEAR THE WEST COAST SHOULD BRING A
DRYING TREND FOR THE MIDDLE TO LATTER PART OF THE WEEK. THERE MAY
STILL BE ENOUGH RESIDUAL MOISTURE FOR AFTERNOON THUNDERSTORMS OVER
THE MOUNTAINS TUESDAY. AS THE MOISTURE DECREASES...INLAND AREAS WILL
WARM.
&&
.AVIATION...
200930Z...COAST/VALLEYS...STRATUS WITH BASES 1200-1500 FT MSL HAS
MOVED 15-20SM. LOW CLOUDS EXPECTED TO CLEAR IN THE VALLEYS 15-17Z
AND ALONG THE COAST 18-20Z...WITH SOME CLOUDS CLINGING TO THE
BEACHES THROUGH THE AFTERNOON. STRATUS RETURNING TO COASTAL AIRPORTS
01-03Z WITH SIMILAR BASES AND TOPS. OTHERWISE...SCT-BKN CLOUDS AOA
8000 FT MSL AND AREAS OF SMOKE FROM THE MOUNTAIN FIRE...ESPECIALLY
IN THE SOUTHERN INLAND EMPIRE. A SLIGHT CHANCE OF LIGHT SHOWERS AND
THUNDERSTORMS BEGINNING SAT AFTERNOON. ANY TSTMS THAT DEVELOP WILL
LIKELY PRODUCE LITTLE RAIN AND GUSTY SFC WINDS.
MTNS/DESERTS...SCT-BKN CLOUDS AOA 8000 FT MSL. EASTERLY WINDS MAY
INCREASE EARLY THIS MORNING FOR A SHORT TIME OVER THE LOW DESERTS AS
OUTFLOW FROM THUNDERSTORMS MOVES THROUGH. OTHERWISE...A CHANCE OF
SHOWERS AND THUNDERSTORMS BEGINNING SAT AFTERNOON...WITH THE BEST
CHANCES OVER THE MTN RIDGES. BASES WILL BE NEAR 8-10K FT WITH TOPS
TO 40K FT.
&&
.MARINE...
LONG PERIOD SOUTH-SOUTHWEST SWELL CURRENTLY PEAKING WITH A
REINFORCING 3-4 FT/16-17 SEC PERIOD SWELL ARRIVING LATER TODAY. THIS
WILL CONTINUE ELEVATED SURF AND STRONG RIP CURRENTS ALONG SOUTH AND
SOUTHWEST FACING BEACHES THROUGH THE WEEKEND WITH LOCAL SURF SETS
AROUND 7 FEET POSSIBLE...MAINLY IN ORANGE COUNTY. HIGH TIDES WILL BE
ABOVE 7 FEET EACH EVENING SAT THROUGH MON. THE COMBINATION OF
ELEVATED SURF AND HIGH TIDES MAY PRODUCE MINOR COASTAL FLOODING
ALONG VULNERABLE LOW-LYING AREAS. A BEACH HAZARDS STATEMENT
CONTINUES THROUGH SUN EVENING. SURF AND SWELL WILL DIMINISH EARLY
NEXT WEEK.
&&
.FIRE WEATHER...
A MOIST EAST FLOW PATTERN WILL BRING INCREASING MONSOONAL MOISTURE
WITH PERIODS OF SHOWERS AND ISOLATED THUNDERSTORMS WITH WETTING
RAINS THROUGH MONDAY...DECREASING ON TUESDAY. THUNDERSTORM WIND
GUSTS TO 40 MPH ARE POSSIBLE WITH FLASH FLOODING POSSIBLE IN RECENT
BURN AREAS. WARMER AND DRIER FOR THE LATTER HALF OF NEXT WEEK WITH
SOUTHWEST FLOW ALOFT.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...FLASH FLOOD WATCH THROUGH SUNDAY EVENING FOR BURN AREAS OF THE
RIVERSIDE COUNTY MOUNTAINS...SAN DIEGO COUNTY DESERTS...SAN
DIEGO COUNTY MOUNTAINS.
BEACH HAZARDS STATEMENT THROUGH SUNDAY EVENING FOR THE BEACHES
IN THE ORANGE COUNTY COASTAL AREAS...SAN DIEGO COUNTY
COASTAL AREAS.
PZ...NONE.
&&
$$
PUBLIC...17
AVIATION/MARINE...TS
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1125 PM MDT FRI JUL 19 2013
.UPDATE...
ISSUED AT 730 PM MDT FRI JUL 19 2013
UPDATED TO CANCEL FLASH FLOOD WATCH FOR EL PASO AND TELLER
COUNTIES. LATEST HIGHER RESOLUTION MODEL RUNS OF THE HRRR AND RAP
ARE NOT INDICATING AS MUCH UPSTREAM DEVELOPMENT AS PREVIOUS RUNS.
THIS IS SUPPORTED BY CURRENT RADARS INDICATING A ONLY FEW STORMS
IN PARK COUNTY WEST OF TARRYALL RESERVOIR...AS WELL AS A FEW MORE
STORMS ACROSS THE NORTHERN MTS OF SUMMIT...GRAND AND LARIMAR
COUNTIES AT THIS TIME. RADAR AND MODEL TRENDS HAVE THIS STORMS
MOVING SOUTH AND WEAKENING THROUGH THE REST OF THE EVENING...WITH
THE THREAT OF FLASH FLOODING DIMINISHING AS WELL.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 238 PM MDT FRI JUL 19 2013
AN UPR RIDGE WL REMAIN CENTERED OVR NV TONIGHT AND SATURDAY. A UPR
DISTURBANCE WL CONTINUE MOVING SOUTH ACRS THE FORECAST AREA
TONIGHT. THERE IS PLENTY OF MOISTURE OVER THE AREA AS WELL. ALL
THE INGREDIENTS SEEM TO BE IN PLACE TO BRING WIDESPREAD PCPN OVR AND
NR THE MTS...WITH SCT ACTIVITY OVR THE SERN PLAINS. THE STEERING
FLOW WL REMAIN FAIRLY LIGHT...RESULTING AND SLOW MOVING STORMS AND
THUS UNDER THE HEAVIER STORMS...LOCALLY HEAVY RAIN COULD FALL. THIS
BECOMES A BIG CONCERN IF IT OCCURS OVR THE BURNS SCARS AS MUD AND
ASH FLOWS COULD OCCUR. WL LEAVE THE FLASH FLOOD WATCH IN EFFECT FOR
EL PASO AND TELLER COUNTIES. AS THE UPR DISTURBANCE MOVES SOUTHWARD
OVR THE AREA...BOTH THE RAP13 AND NAM SHOW THE FOCUS OF PCPN
SHIFTING SOUTHWARD THIS EVENING OVR THE SRN MTS AND SOUTH OF HIGHWAY
50. THE HRRR ALSO SHOWS WIDESPREAD PCPN AND CHANCES FOR RAIN OVR
SRN AREAS...BUT ALSO INCREASES PCPN CHANCES OVR EL PASO...TELLER
COUNTIES AND PUEBLO COUNTIES DURING THE EVENING HOURS.
OVERNIGHT...PCPN CHANCES ARE EXPECTED TO DECREASE OR END FROM NORTH
TO SOUTH...WITH SOME LIGHT PCPN POSSIBLY LINGERING THRU THE NIGHT
OVR FAR SOUTHERN AREAS. IT LOOKS DRIER IN THE UPR LEVELS ON SATURDAY
AS THE MSTR PLUME SHIFTS SOUTH OF THE AREA...BUT THERE WL STILL BE
PLENTY OF LOW LEVEL MSTR TO WORK WITH FOR SCT TO LIKELY POPS OVR THE
MTS AND PROBABLY ISOLD TO SCT POPS OVR THE SERN PLAINS. STORMS
SHOULD BE FAIRLY SLOW MOVING AGAIN AND WE COULD SEE SOME LOCALIZED
HEAVY RAIN.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 238 PM MDT FRI JUL 19 2013
UPPER LEVEL FLOW TURNS SLIGHTLY MORE NORTHWESTERLY SUNDAY...WHICH
WILL TEND TO PUSH THE MOIST PLUME SOUTH OF THE STATE INTO NM AND
AZ BY AFTERNOON. MODELS SHOW WEAK FRONTAL BOUNDARY DISSIPATING
SOMEWHERE OVER THE ERN PLAINS OF CO...WITH DECREASING LOW LEVEL
MOISTURE AS UPSLOPE WINDS WEAKEN. SUSPECT TSRA WILL STAY ISOLATED
AND LIMITED TO MAINLY THE HIGHER TERRAIN SUN AFTERNOON AND
EVENING...AND WILL END QUICKLY BY LATE EVENING WITH LITTLE IN THE
WAY OF UPPER SUPPORT. MAX TEMPS SUN SHOULD CREEP UPWARD A DEGF OR
TWO...THOUGH 700 MB TEMPS SUGGEST RATHER HOT MET GUIDANCE MAXES
MAY BE JUST A TAD TOO WARM. SIMILAR SET-UP MON/TUE...AS WEAK
SURFACE FRONT REFORMS OVER NORTHEAST COLORADO AND AIR MASS OVER
SOUTHERN COLORADO CONTINUES TO DRY. AGAIN EXPECT ISOLATED
MOUNTAIN CONVECTION BOTH DAYS...THOUGH COVERAGE AND RAINFALL
AMOUNTS WILL BE RATHER SPARSE. 700 MB TEMPS CREEP UPWARD INTO THE
18C-20C RANGE...WHICH SHOULD PRODUCE A FEW 100F PLUS READINGS OVER
THE EASTERN PLAINS BOTH DAYS. ON WED...FRONT DROPS SOUTH OVER THE
PLAINS LEADING TO A RENEWED WESTWARD SURGE OF MOISTURE OVER THE
EASTERN MOUNTAINS AND PLAINS BY AFTERNOON. GFS AND ECMWF ARE
SIMILAR WITH SURFACE FEATURES...BUT ONLY GFS BREAKS OUT CONVECTION
THU EVENING...WHILE ECMWF STAYS DRY. WILL LEAN TOWARD THE WETTER
SOLUTION OF THE GFS FOR NOW...GIVEN THE DEEPER MOISTURE AND
INSTABILITY BEHIND THE FRONT. FARTHER WEST...LOW GRADE MONSOON
REDEVELOPS WED AS SLIGHTLY DEEPER MID LEVEL MOISTURE PUSHES BACK
INTO THE STATE...LEADING TO BETTER TSRA COVERAGE THAN MON/TUE.
PAST WED...MOISTURE LOOKS TO SLOSH BACK AND FORTH ACROSS THE
EASTERN PLAINS...WITH PERHAPS A DECREASE IN PRECIP CHANCES THU AND
AN INCREASE FRI. OVER THE MOUNTAINS...UPSWING IN CONVECTION LOOKS
POSSIBLE FRI AS WELL...ESPECIALLY AS LAST FEW MODEL RUNS OF BOTH
THE ECMWF AND GFS TRY TO BUILD THE UPPER RIDGE EASTWARD INTO
TX...ALLOWING A RENEWED INFLUX OF MOISTURE FROM THE SOUTH.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1125 PM MDT FRI JUL 19 2013
VFR CONDITIONS EXPECTED AT TAF SITES THROUGH THE REST OF THE NIGHT
WITH MID AND HIGH LEVEL CONVECTIVE DEBRIS CLOUDS CONTINUE TO
DIMINISH. WITH THIS EVENINGS PRECIPITATION...COULD SEE SOME PATCHY
FOG DEVELOPING ACROSS THE AREA THROUGH THE EARLY MORNING HOURS WITH
BEST CHANCES AT COS AND ALS...THOUGH NOT ENOUGH CONFIDENCE TO PUT
IN TAFS AT THIS TIME. MODELS INDICATING LESS COVERAGE OF STORMS
TOMORROW AS DRIER AIR IN THE WEAK NORTHERLY FLOW ALOFT MOVES INTO
THE AREA. STILL SHOULD SEE SCATTERED STORMS ACROSS THE MTS WITH
BEST CHANCES OF STORMS AFFECTING TERMINAL BEING AT COS...THOUGH
HAVE KEPT VCTS IN PLACE AT THIS TIME.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...MW
SHORT TERM...28
LONG TERM...PETERSEN
AVIATION...MW
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
355 AM EDT Sat Jul 20 2013
.NEAR TERM [Today and Tonight]...
The high-resolution model guidance appears to have been reasonably
accurate in depicting an increase in convective coverage and rain
rates around 06-08 UTC. The showers that have developed so far
appear to be dominated by warm rain processes - low-topped
convection that is very efficient in producing rainfall. The TLH
airport recorded around one half inch of rain in just under a half
hour with one of these showers. The HRRR and preponderance of CAM
guidance shows a general 1-2" of rain on average can be expected
through mid-afternoon over most of our Florida zones (where the
heaviest rain is most likely). However, the vast majority of those
models also show localized amounts in the 7-9" range, which would
likely be sufficient to cause localized flash flooding. Because of
this, we have issued a Flash Flood Watch in effect until 23 UTC for
all of our Florida zones.
PoPs were adjusted to show 60-80% values this morning across our
Florida zones, with "likely" PoPs (60-70%) spreading north into our
Alabama and Georgia zones in the late morning and afternoon. The
abundance of rain and cloud cover will likely once again restrict
the diurnal temperature range, so high temperatures were kept cooler
than normal values, and similar to the inherited forecast.
Indications are that convective coverage will diminish between 21
and 03 UTC, with a lull tomorrow evening.
&&
.SHORT TERM [Sunday Through Monday]...
While at this time yesterday it had appeared that there would be
some legitimate hope that a brief period of Upper level ridging
could push far enough northward in the Gulf of Mexico to at least
give our region a brief break in the unsettled weather, each
consecutive run of the ECMWF continues to squash that little bit of
hope. If the Upper ridge stays weak and in the Central Gulf of
Mexico, the probability of conditions that are wetter and cooler
than climo will increase, and for those looking for a break in the
persistent Upper trough (and accompanying sunnier and drier
conditions) may have to wait until next summer.
&&
.LONG TERM [Monday Night through Friday]...
The GFS and ECMWF forecast a 500mb trough to develop over the
Southeast over the upcoming work week. It`s difficult to forecast
specifics in such patterns as there will undoubtedly be minor short
waves rotating through this broader trough, which can help trigger
periods of active deep moist convection (sometimes even overnight).
The best approach is to "broad brush" above-average rain chances
(generally 50-60% each day, and 20-30% each night) across the
region, which is near the GFS-ECMWF MOS PoP blend. Temperatures will
be near average, with highs in the lower to mid 90s (inland) and
lows in the 70s.
&&
.AVIATION [through 12 UTC Sunday]...
Some IFR-MVFR CIGS could develop at our three northern terminals
(DHN, ABY, VLD) out ahead of the rain showers that are developing
near the Gulf. These will likely diminish as the rain advances north
this morning. Meanwhile, MVFR-VFR should prevail at TLH and ECP,
with tropical rain showers having the potential to reduce visibility
at times to IFR. These tropical rain showers will spread inland
during the day, with the potential to eventually affect the
remaining terminals (ABY, DHN, VLD). Rain will diminish by 21-03 UTC
with VFR through the evening.
&&
.MARINE...
Moderate onshore winds today have created slightly higher seas than
expected, so did bump up seas about 1 foot across the board for
today. Winds and seas will diminish a bit back to more typical
summertime levels on Sunday and Monday, before becoming moderate
again out of the west by mid week, as the surface pressure pattern
increases slightly.
&&
.FIRE WEATHER...
Red flag conditions are not expected for the next several days.
&&
.HYDROLOGY...
Numerous tropical rain showers and rain bands are beginning to
develop early this morning in a very moist environment. The humid
air mass is due to a large plume of tropical moisture. A variety of
model guidance shows a general inch of rainfall averaged across all
of the Florida panhandle and big bend. However, there are also
indications that localized amounts could be well in excess of that.
Small heavy rain bands are not uncommon in a tropical environment
such as this, and they can lead to localized flash flooding. The
rain should begin to decrease in coverage closer to sunset. Impacts
on area rivers are difficult to pinpoint at this time, but certainly
areas near Bruce, Lamont, and Newport in Florida should be on alert
for potential rises back to Flood Stage.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 84 73 90 74 91 / 80 30 60 30 40
Panama City 84 76 88 76 88 / 70 50 60 30 40
Dothan 87 73 90 73 91 / 70 30 60 30 50
Albany 87 73 91 74 91 / 70 30 60 30 50
Valdosta 85 72 92 73 92 / 70 30 60 30 50
Cross City 88 73 90 73 90 / 60 30 60 20 40
Apalachicola 84 76 88 75 88 / 70 50 50 20 40
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...FLASH FLOOD WATCH through this evening for Calhoun-Central
Walton-Coastal Bay-Coastal Dixie-Coastal Franklin-Coastal
Gulf-Coastal Jefferson-Coastal Taylor-Coastal Wakulla-
Gadsden-Holmes-Inland Bay-Inland Dixie-Inland Franklin-
Inland Gulf-Inland Jefferson-Inland Taylor-Inland Wakulla-
Inland Walton-Jackson-Lafayette-Leon-Liberty-Madison-
South Walton-Washington.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Lamers
SHORT TERM...Gould
LONG TERM...Fournier
AVIATION...Lamers
MARINE...Gould
FIRE WEATHER...Lamers
HYDROLOGY...Lamers/Gould
AREA FORECAST DISCUSSION
NWS TOPEKA KS
352 AM CDT SAT JUL 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT SAT JUL 20 2013
TODAY AND TONIGHT...A LONGER WAVE LENGTH UPPER LEVEL TROUGH WILL
CONTINUE TO AMPLIFY ACROSS THE UPPER MIDWEST AND GREAT LAKES STATES.
THIS WILL CAUSE THE UPPER FLOW ACROSS THE PLAINS TO BECOME
NORTHWESTERLY. SHORTER WAVE LENGTH UPPER LEVEL TROUGHS WILL ROUND
THE UPPER RIDGE AXIS ACROSS THE WESTERN CONUS AND DIG SOUTHEAST
ACROSS THE CENTRAL PLAINS THROUGH TONIGHT. A WEAK FRONTAL BOUNDARY
WAS LOCATED FROM SOUTHWEST KS...NORTHEAST TO NEAR TOP...THEN
NORTHEAST ACROSS NORTHERN MO. WEAK ISENTROPIC LIFT NORTH OF THE
BOUNDARY MAY CAUSE A FEW SHOWERS TO DEVELOP THIS MORNING ACROSS EAST
CENTRAL KS.
MOST NUMERICAL MODELS SHOW AN H5 TROUGH DIGGING SOUTHEAST ACROSS
CENTRAL HIGH PLAINS DURING THE AFTERNOON HOURS. THE ASCENT AHEAD OF
THE H5 TROUGH COMBINED WITH UPSLOPE FLOW WILL CAUSE A COMPLEX OF
THUNDERSTORMS TO DEVELOP ACROSS WESTERN NE LATE THIS AFTERNOON AND
EARLY EVENING...THEN MOVE SOUTHEAST ACROSS EASTERN KS LATER TONIGHT.
ISOLATED TO WIDELY SCATTERED THUNDERSTORMS MAY ALSO DEVELOP ALONG
THE NORTHWARD MOVING FRONTAL BOUNDARY ACROSS THE CWA DURING THE LATE
AFTERNOON AND EARLY EVENING HOURS. THE 00Z NAM AND RAP MODELS WERE
SHOWING 1500-2500 J/KG OF MLCAPE. HOWEVER...THE SFC-6KM EFFECTIVE
SHEAR WILL ONLY BE 15 TO 20 KTS DURING THE AFTERNOON AND EARLY
EVENING HOURS. DUE TO THE WEAKER VERTICAL WINDSHEAR UPDRAFTS WILL
PROBABLY NOT BE ABLE TO SUSTAIN THEIR INTENSITY FOR MORE THAN 15 TO
20 MINUTES. THE STRONGER THUNDERSTORMS MAY PRODUCE SMALL HAIL AND 40
TO 50 MPH WINDS GUSTS. A STORM OR TWO MAY BRIEFLY PRODUCE QUARTER
SIZE HAIL AND 58 MPH WINDS GUSTS.
THE INSTABILITY AND VERTICAL WIND SHEAR AND INSTABILITY LOOKS TOO
WEAK FOR THE COMPLEX OF THUNDERSTORMS LATE TONIGHT TO BE
SEVERE...SOME OF THE STRONGER STORMS MAY PRODUCE GUSTY WINDS AND
THERE COULD BE HEAVY RAINFALL ALONG THE TRACK OF THE THUNDERSTORM
COMPLEX. I KEPT LIKELY POPS FOR THE NORTHERN AND EASTERN COUNTIES OF
THE CWA AFTER MIDNIGHT. THIS MAY CHANGE DEPENDING TO WHERE THE MCS
ACROSS NE FORMS AND HOW IT TRACKS THROUGH THE NIGHT. ATTM...MOST
MODELS HAVE THE COMPLEX OF STORMS MOVING SOUTHEAST ACROSS SOUTH
CENTRAL NE AND ACROSS THE EASTERN CWA LATE TONIGHT AND THROUGH THE
MORNING HOURS OF SUNDAY.
BROKEN TO SCATTED CLOUD COVER AND LIGHT SOUTHEAST WINDS WILL KEEP
HIGH TEMPERATURES TODAY IN THE LOWER TO MID 90S ACROSS THE CWA.
HIGHER SURFACE DEWPOINTS IN THE MID TO UPPER 60S WILL CAUSE HEAT
INDICES TO RISE INTO THE UPPER 90S.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 350 AM CDT SAT JUL 20 2013
THE COMBINATION OF PERSISTENT UPPER RIDGING IN THE INTERMOUNTAIN
WEST AND TROUGHING IN THE GREAT LAKES AREA WILL PRIMARILY KEEP THE
COUNTY WARNING AREA IN NORTHWEST FLOW ALOFT THROUGH THE END OF THE
UPCOMING WORK WEEK. IN GENERAL THIS WILL KEEP AN AXIS OF LOW LEVEL
MOISTURE IN PLACE FROM KS WEST AND NORTHWESTWARD INTO THE CENTRAL
HIGH PLAINS THROUGH THE PERIOD. AS A SERIES OF SHORTWAVE TROUGHS
MOVING THROUGH THE FLOW ALOFT...THERE WILL BE (DEPENDING ON THE
TIMING OF EACH SHORTWAVE) THE OPPORTUNITY FOR CONVECTION TO DEVELOP
AND MOVE EAST AND SOUTHEAST WITHIN THIS MOISTURE AXIS...ALTHOUGH THE
LLVL JET WILL NOT BE PARTICULARLY STRONG THIS SETUP ALONG WITH
POSSIBLE OUTFLOW/WEAK FRONTAL BOUNDARIES FROM EARLIER MCS`S SHOULD
PROVIDE SEVERAL OPPORTUNITIES FOR RAIN IN THE WEEK AHEAD. ALTHOUGH
THE MODELS OFFER DIFFERENT SOLUTIONS ON THE STRENGTH AND TIMING OF
THESE SHORTWAVE TROUGHS...THE BETTER CHANCES FOR THUNDERSTORMS
APPEARS TO BE SUNDAY INTO SUNDAY NIGHT WITH THE PASSAGE OF A
SHORTWAVE TROUGH...THEN AGAIN WITH AN STRONGER WAVE TUESDAY NIGHT
INTO WEDNESDAY MORNING. FOCUSED THE HIGHER POPS IN THESE PERIODS
WHERE PERSISTENT AND CONFIDENCE IS HIGHER. MESOSCALE FEATURES WITH
ANY MCS`S WILL LIKELY COMPLICATE THE FORECAST FROM DAY TO DAY.
ANOTHER CHALLENGE THIS WEEK IN THIS PATTERN WILL BE TEMPERATURES
AS THE CWA WILL FREQUENTLY BE LOCATED ON THE EASTERN PERIPHERY OF A
STRONG THERMAL AXIS MUCH OF THE WEEK. AS THE LLVL FLOW VEERS...THERE
WILL BE AN ENHANCED OPPORTUNITY FOR VERY WARM AIR TO BE ADVECTED
EASTWARD INTO THE CWA. THIS OCCURS ON MONDAY INTO TUESDAY...WITH
SOME INDICATIONS OF ANOTHER SURGE OF MUCH WARMER AIR TOWARDS THE END
OF THE WEEK. HOWEVER...PERIODIC CHANCES FOR PRECIP/THICKER CLOUDS
WILL CONTINUE TO BE POSSIBLE OFFSETTING FACTORS. WILL MAINTAIN
HIGHS GENERALLY IN THE 90S THROUGH THE FCST...ALTHOUGH THE EFFECTS
OF CLOUDS/PRECIP ON SUNDAY WILL LIMIT HIGHS TO THE 80S IN MANY AREAS
SUNDAY WITH POST FRONTAL HIGHS ON WEDNESDAY IN THE 80S AS WELL. AT
THIS POINT...THE HIGHEST HEAT INDICES THIS WEEK APPEAR WILL OCCUR ON
MONDAY WITH READINGS COMMONLY IN THE RANGE OF 100 TO 104 DEGREES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1154 PM CDT FRI JUL 19 2013
FOR THE 06Z TAFS...THE SCATTERED SHOWERS AND THUNDERSTORMS FROM THIS
EVENING WILL CONTINUE TO WEAKEN AND DIMINISH INTO THE EARLY
OVERNIGHT HOURS. WINDS OVERNIGHT WILL BE CALM...BECOMING LIGHT OUT
OF THE SOUTHEAST THROUGH THE DAY ON SATURDAY. ADDITIONAL CHANCES
FOR SCATTERED SHOWERS AND THUNDERSTORMS EXISTS ACROSS THE REGION
SATURDAY NIGHT. THERE IS STILL UNCERTAINTY IN THE EXACT TIMING AND
LOCATION OF ANY PRECIPITATION...SO HAVE JUST ADDED THE MENTION OF
VCTS ATTM AND WILL CONTINUE TO ADJUST WITH FUTURE UPDATES.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GARGAN
LONG TERM...63
AVIATION...HENNECKE
AREA FORECAST DISCUSSION
NWS WICHITA KS
350 AM CDT SAT JUL 20 2013
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 344 AM CDT SAT JUL 20 2013
TODAY-TONIGHT:
LOW CONFIDENCE FORECAST WITH SHORT TERM/HIGH RESOLUTION GUIDANCE
SHOWING MANY POSSIBLE SCENARIOS AND MOST HAVE BEEN STRUGGLING OUT
OF THE BOX. HAVE USED A COMBO OF HRRR AND ECMWF AS BOTH NAM/GFS
SEEM QUITE OPTIMISTIC WITH CAPE/PRECIPITATION FOR LATER TODAY.
WEAK FLOW ALOFT MAKES IT HARD TO DETERMINE WHERE THINGS WILL MOVE
AND GIVEN WEAK FORCING...BOUNDARIES WILL LIKELY BE THE KEY TO
CONVECTIVE INITIATION. AT THIS TIME...THINKING WEAK SURFACE
BOUNDARY FROM GBD-RSL-MHK WILL LIKELY NOT MOVE VERY MUCH...SO WILL
DRIBBLE ISOLATED POPS ALONG/NORTH OF BOUNDARY THIS MORNING.
CHANCES SHOULD INCREASE A BIT LATE AFTERNOON BUT MORE LIKELY THIS
EVENING. ECMWF KEEPS THE BULK OF THE PRECIPITATION IN CENTRAL KS
OVERNIGHT AND POPS MAY BE OVERDONE ACROSS THE SOUTHERN HALF OF THE
AREA.
SUN-MON:
BETTER UPPER FORCING IS ANTICIPATED AS DAY WEARS ON SUN BUT
FORECAST IS COMPLICATED BY POSSIBLE OUTFLOW FROM STORMS OVER NE KS
IN THE MORNING. SUSPECT ANOTHER ROUND OF STORMS WILL DEVELOP IN
NORTHWEST FLOW AND MOVE ACROSS FLINT HILLS/SOUTHEAST KS SUN NIGHT.
THIS SHOULD EXIT SOUTHEAST KS AROUND SUNRISE. MAY SEE SOME
INCREASE IN CAPPING ON MON AND GIVEN LESS FORCING...PRECIPITATION
CHANCES SHOULD DIMINISH. SHADED TEMPERATURES DOWN A BIT IN THE
EASTERN HALF AND WARMER IN WEST BASED ON CLOUDS BOTH DAYS.
-HOWERTON
.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 344 AM CDT SAT JUL 20 2013
AGAIN FAIRLY GOOD AGREEMENT BETWEEN 0000 UTC RUNS OF GFS/ECMWF
OVERALL PATTERN UNTIL FRI. HOWEVER DETAILS ON PRECIPITATION CHANCES
ARE STILL IN LESS AGREEMENT AND COMBINED WITH GRID INITIALIZATION
ISSUES...WILL END UP WITH CONSIDERABLE PRECIPITATION MENTIONED THIS
PERIOD. STILL APPEARS TO BE AN INCREASED CHANCE FOR PRECIPITATION
TUE NIGHT AS SHORTWAVE MOVES DOWN NORTHWEST FLOW. SURFACE FRONT
MAY BE MOVING INTO THE AREA ON FRI...BUT UNCERTAINTY IS HIGH ON
TIMING. -HOWERTON
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1139 PM CDT FRI JUL 19 2013
SCATTERED SHOWERS AND THUNDERSTORMS ARE DIMINISHING AS WE APPROACH
06Z. EXPECT ACTIVITY TO WANE THROUGH 12Z AND INTO THE
MORNING/EARLY AFTERNOON HOURS BEFORE ANOTHER ROUND OF SHOWER AND
THUNDERSTORM ACTIVITY IS POSSIBLE IN THE AFTERNOON. CANNOT RULE
OUT SOMETHING IN THE MORNING...BUT DO NOT HAVE IT REPRESENTED IN
THE TAF FORECAST AT THIS TIME. WINDS BEHIND THE CONVECTION ARE
LIGHT AND OUT OF THE EAST. WINDS WILL GRADUALLY BECOME SOUTHERLY
BY MORNING ACROSS THE AREA AND INCREASE SLIGHTLY DURING THE DAY.
VFR CONDITIONS ARE EXPECTED TO PREVAIL.
BILLINGS
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 96 72 93 73 / 20 20 20 20
HUTCHINSON 95 70 94 71 / 20 20 20 20
NEWTON 93 70 92 70 / 20 30 30 20
ELDORADO 94 71 92 70 / 20 20 30 30
WINFIELD-KWLD 96 73 93 74 / 20 20 20 20
RUSSELL 94 67 98 68 / 30 30 20 20
GREAT BEND 94 66 97 68 / 20 20 20 20
SALINA 95 70 94 71 / 30 40 40 30
MCPHERSON 95 70 94 70 / 30 30 30 20
COFFEYVILLE 97 72 94 72 / 20 20 20 40
CHANUTE 94 71 92 71 / 20 30 30 40
IOLA 93 71 91 71 / 30 30 40 40
PARSONS-KPPF 96 72 93 71 / 20 20 30 40
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
330 AM EDT SAT JUL 20 2013
.SYNOPSIS...
ISSUED AT 330 AM EDT SAT JUL 20 2013
FAIR WEATHER WILL RETURN THIS WEEKEND WITH SEASONABLE TEMPERATURES
AND IT WILL BE MUCH LESS HUMID. HIGHS WILL BE CLOSER TO NORMALS FOR
THIS TIME OF YEAR WITH LOWER TO MIDDLE 80S TODAY AND AROUND 80 ON
SUNDAY. THE NEXT CHANCE OF SHOWERS AND STORMS WILL COME LATE SUNDAY
NIGHT AND MONDAY.
&&
.SHORT TERM...(TODAY THROUGH MONDAY AFTERNOON)
ISSUED AT 330 AM EDT SAT JUL 20 2013
HIGH PRESSURE WILL BRING FAIR WEATHER THIS WEEKEND WITH SEASONABLE
TEMPERATURES. HIGH TEMPERATURES TODAY WILL REACH THE LOWER TO MIDDLE
80S AND UPPER 70S TO LOWER 80S ON SUNDAY.
A LOW PRESSURE SYSTEM WILL BRING THE NEXT CHC FOR SHOWERS AND
TSTORMS AS EARLY AS LATE SUNDAY NIGHT WITH A LITTLE BETTER CHC FOR
PCPN ON MONDAY AS AN UPPER LEVEL TROF AXIS MOVES ACROSS THE LOWER
GREAT LAKES REGION.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 330 AM EDT SAT JUL 20 2013
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 726 PM EDT FRI JUL 19 2013
THE BIG QUESTION IS DOES A LINE OF STORMS FORM JUST AHEAD OF THE
FRONT OR NOT? CURRENTLY SCATTERED STORMS ARE TRYING TO ORGANIZE
NEAR MBL...WHICH IS JUST AHEAD OF THE COLD FRONT. THE TIMING TOOL
TAKES THAT TO MKG BY 0430Z AND TO THE I-94 TAF SITES BY 11Z. THIS
SEEMS TO SLOW... THE LATEST HRRR REDEVELOPS STORMS OVER SOUTHERN
LAKE MICHIGAN BY 01Z AND HEADS THOSE STORMS OUT OF THE CWA BY 04Z.
SINCE THERE IS A JET SPEED MAX THAT COMES THROUGH THE AREA IN THE
03Z TIME FRAME... IT WOULD SEEM THERE IS A GOOD CHANCE THE STORMS
COULD YET BETTER ORGANIZE. SO NOT HAVING ANYTHING SOLID TO TRACK
INTO THE TAF SITES...I KEPT THE VCTS GOING 09Z AT MOST OF THE TAF
SITES. BEHIND THE FRONT SKIES WILL CLEAR SO MOST OF SATURDAY
SHOULD BE CLEAR WITH A NORTHWEST WIND AROUND 10 KNOTS.
&&
.MARINE...
ISSUED AT 330 AM EDT SAT JUL 20 2013
WAVE HEIGHTS WILL RAMP BACK UP LATER TODAY AS NNW TO NORTH WINDS
INCREASE LATE THIS MORNING/AFTN. WE WILL HOIST A SMALL CRAFT
ADVISORY TO COVER THIS FROM LATE THIS MORNING THROUGH THE LATE
EVENING HOURS TONIGHT. A BEACH HAZARD STATEMENT HAS ALSO BEEN
ISSUED DETAILING THE HIGH SWIM HAZARD RISK THAT IS IN PLAY AGAIN
TODAY.
&&
.HYDROLOGY...
ISSUED AT 330 AM EDT SAT JUL 20 2013
NO HYDRO ISSUES WITH HIGH PRESSURE BUILDING IN THIS WEEKEND BRINGING
FAIR AND DRY WX.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT 11 AM TODAY THROUGH LATE THIS
EVENING FOR MIZ037-043-050-056-064-071.
LM...SMALL CRAFT ADVISORY 11 AM TODAY THROUGH LATE THIS EVENING
FOR LMZ844>849.
&&
$$
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...MJS
AVIATION...WDM
HYDROLOGY...LAURENS
MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
414 AM CDT SAT JUL 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM CDT SAT JUL 20 2013
WE ARE LOOKING AT ONE OF OUR BETTER CHANCES OF SHOWERS AND
THUNDERSTORMS THIS EVENING INTO TONIGHT.
THIS IS A DIFFICULT FORECAST WHEN IT COMES TO THE CHANCE OF
PRECIPITATION. WE HAVE BEEN DRY ACROSS THE FORECAST AREA EARLY THIS
MORNING. HOWEVER...A FEW FORECAST MODELS LIKE THE HRRR ATTEMPT TO
DEVELOP SHOWERS AND THUNDERSTORMS ALONG OLD OUTFLOW BOUNDARIES A
LITTLE LATER THIS MORNING. OVERALL FORCING IS WEAK THIS MORNING AND
WILL ONLY CALL FOR LOW END SLIGHT POPS THROUGH NOON ACROSS NORTH
CENTRAL KANSAS AND FOR AREAS PRIMARILY ALONG AND WEST OF HIGHWAY
281. THUNDERSTORMS ARE MOST LIKELY TO DEVELOP OVER THE NEBRASKA
SANDHILLS INTO SW SOUTH DAKOTA DURING THE MID TO LATE AFTERNOON
HOURS ALONG A SOUTHEASTWARD MOVING SFC TROUGH OF LOW PRESSURE.
SEVERAL FORECAST MODELS SUCH AS THE 06Z NAM AND 00Z GFS CONGEAL
CONVECTION THIS EVENING INTO A LARGE RAIN MAKING CLUSTER CALLED
AN MCS OR MESOSCALE CONVECTIVE SYSTEM THAT WOULD TRACK ACROSS OUR
FORECAST AREA. CONSEQUENTLY...WILL CONTINUE TO CARRY THE LIKELY
POPS FOR THIS EVENING. DEEP LAYER WIND SHEAR VALUES WILL GENERALLY
RANGE FROM 30 TO 35 KTS AND MLCAPE WILL BE MODEST...REACHING UP
CLOSE TO 2000 J/KG. THEREFORE...THE ENVIRONMENT WILL SUPPORT THE
POSSIBILITY OF SEVERE THUNDERSTORMS WITH THE PRIMARY FOCUS BEING
DURING THE EVENING HOURS. THIS IS PRIMARILY A WIND AND HAIL THREAT
WITH NOT MUCH OF A TORNADO THREAT GIVEN THE SHEAR IS WEAK IN THE
LOWEST ATMOSPHERIC LAYERS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 408 AM CDT SAT JUL 20 2013
MAIN FORECAST CONCERNS WILL BE THE CHANCES FOR THUNDERSTORMS AND
TEMPERATURES.
MODELS ARE SIMILAR IN THE MAIN FEATURES DURING THIS PERIOD WITH
NORTHWEST FLOW ACROSS THE AREA AND SEVERAL UPPER LEVEL WAVES MOVE
THROUGH THE REGION. EACH OF THEM HAVE THE POTENTIAL TO BRING A
CHANCE FOR THUNDERSTORMS TO THE AREA. THE MAIN DIFFERENCES IN THE
MODELS IS THAT THE TIMING OF THE INDIVIDUAL WAVES HAS SOME
DIFFERENCES AND HOW STRONG THEY ARE. IT DEFINITELY WILL NOT RAIN
EVERY DAY OR AT EVERY LOCATION...BUT THERE IS MAINLY SMALL CHANCES
NEARLY EVERY DAY.
THE PRECIPITATION FROM SATURDAY NIGHT WILL MOVE OUT OF THE AREA
SUNDAY MORNING BUT ANOTHER WAVE WILL MOVE INTO THE AREA SUNDAY
AFTERNOON AND EVENING AND BRING ANOTHER CHANCE FOR THUNDERSTORMS.
THE THUNDERSTORMS SHOULD BE NEARLY OUT OF THE AREA DURING THE
OVERNIGHT HOURS SUNDAY NIGHT. MONDAY MORNING WILL ALSO CONTINUE DRY
BEFORE THE NEXT WAVE MOVES INTO THE AREA MONDAY AFTERNOON AND MONDAY
NIGHT. ANOTHER WAVE MOVES IN TUESDAY AND TUESDAY NIGHT. THIS IS A
FAIRLY STRONG WAVE AND CHANCES ARE A LITTLE BETTER FOR SOME
PRECIPITATION...WITH A SURFACE LOW AND WEAK COLD FRONT THAT MOVE
THROUGH THE AREA.
ONCE THE PRECIPITATION MOVES OUT TUESDAY NIGHT...WEDNESDAY AND
WEDNESDAY NIGHT LOOK TO BE DRY WITH A BREAK IN THE SERIES OF UPPER
LEVEL WAVES. BEHIND THE COLD FRONT THERE IS A COOLER SURFACE HIGH
AND TEMPERATURES WILL BE CLOSER TO NORMAL FOR THIS TIME OF YEAR.
THURSDAY THROUGH FRIDAY THERE IS ANOTHER UPPER LEVEL WAVE THAT MOVES
THROUGH THE AREA. THIS ONE IS A LITTLE STRONGER THAN SOME OF THE
OTHERS. THERE IS ANOTHER SURFACE LOW AND COLD FRONT THAT MOVES
THROUGH AND THE CHANCES FOR THUNDERSTORMS RETURN TO THE AREA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1250 AM CDT SAT JUL 20 2013
EXPECT THE WIND WILL REMAIN LIGHT AND OUT OF THE SOUTHEAST THROUGH
THE MORNING...BUT SHOULD INCREASE WITH DIURNAL HEATING AND MAY
EVEN BE A BIT GUSTY AT TIMES THIS AFTERNOON WITH SOME VEERING TO
SOUTH SOUTHEAST. THE WIND WILL AGAIN DIE DOWN BY EARLY EVENING
ONCE WE LOSE THE AFTERNOON HEATING AND SHOULD BACK TO A SOUTHEAST
WIND. WE HAVE AN INCREASING CHANCE OF THUNDERSTORMS AS WE HEAD
THROUGH THE AFTERNOON AND ESPECIALLY BY EVENING. THEREFORE...HAVE
INTRODUCED VICINITY THUNDERSTORMS INTO THE TAF FOR THE EVENING
HOURS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...WESELY
LONG TERM...JCB
AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
256 AM MDT SAT JUL 20 2013
.DISCUSSION...
NOT MUCH CHANGE TO THE GOING FORECAST. AN ACTIVE WEEKEND REMAINS ON
TAP WITH HIGH PWATS...SLOW MOVING STORMS AND THUS...INCREASED FLASH
FLOOD POTENTIAL. PREVIOUS SHIFT ISSUED A FLASH FLOOD WATCH...AND
THIS REMAINS IN GOOD SHAPE. ONE CAVEAT FOR TODAY WILL BE THE AMOUNT
OF DEBRIS CLOUDS FROM LAST NIGHTS/ONGOING CONVECTION ACROSS THE
AREA. IF THE CLOUD COVER LINGERS...THIS WILL LIMIT INSTABILITY THIS
AFTERNOON AND WOULD THEREBY REDUCE RAIN RATES. MODELS MAY BE HINTING
AT THIS A BIT...AS INSTABILITY DOES NOT LOOK TO BE AS STRONG AS
MODELS WERE SUGGESTING 24 HOURS AGO. NONETHELESS...WITH 140-180
PERCENT OF NORMAL PWATS AND NEAR ZERO STORM MOTION...ANY ONE STORM
THAT DEVELOPS COULD POSE FLOODING PROBLEMS. IN ADDITION TO THE HIGH
TERRAIN...REMNANT BOUNDARIES WILL BE THE FOCUS FOR TODAYS
CONVECTION. SIMILAR STORY IN STORE FOR SUNDAY...THOUGH MORE STABLE
AIR STILL LOOKS TO MIGRATE INTO THE EASTERN PLAINS.
MORE DRY AIR WILL WORK INTO NORTHERN AND EASTERN NM ON MONDAY AS THE
UPPER HIGH BEGINS TO MIGRATE EASTWARD FROM NEVADA. THE MOST UNSTABLE
AREA WILL BE ACROSS THE WEST CENTRAL AND SOUTHWEST MOUNTAINS...WHERE
HEAVY RAIN POTENTIAL WILL CONTINUE. BY TUESDAY...THE UPPER HIGH WILL
BE CENTERED OVER WEST CENTRAL COLORADO. WITH THE HIGH EVEN
CLOSER...SUBSIDENCE UNDER THE HIGH WILL LIMIT CONVECTIVE COVERAGE
FURTHER...THOUGH THE FAR WEST WILL HAVE THE BEST POTENTIAL FOR
CONTINUED STORMS.
BY WEDNESDAY...MODELS ARE NOW SUGGESTING THE UPPER HIGH WILL BE
CENTERED OVER FAR NE NM. ISOLD/SCT STORMS WILL REMAIN POSSIBLE
ACROSS THE FAR WEST...BUT GENERALLY QUIET CONDITIONS ARE EXPECTED
ELSEWHERE. BOTH THE ECMWF AND THE GFS TAKE THE UPPER HIGH INTO
TEXAS/OKLAHOMA BY THURSDAY NOW...WHICH OPENS THE DOOR FOR THE
TRADITIONAL MONSOON PLUME. THAT SAID...BY FRIDAY AFTERNOON...THE
HIGH LOOKS TO ELONGATE AND ANY HIGH CENTER BECOMES QUIET MUDDLED.
THEN ON SATURDAY...BOTH MODELS ARE SUGGESTING A BACK DOOR COLD FRONT
WILL ROLL DOWN THE PLAINS AND INCREASE POTENTIAL FOR STORMS ACROSS
THE EAST. STAY TUNED...AS CONFIDENCE REMAINS FAIRLY LOW BEYOND
WEDNESDAY.
34
&&
.FIRE WEATHER...
A VERY ACTIVE FRIDAY WILL BE FOLLOWED BY ANOTHER ACTIVE WEATHER DAY
TODAY. HOWEVER...ONGOING CONVECTION AND CLOUD COVER MAY BE SLOW TO
CLEAR THIS MORNING SO TODAYS ROUND OF SHOWERS AND STORMS COULD GET
A LATER START THAN ON FRIDAY. POTENTIAL FOR HEAVY RAIN AND FLASH
FLOODING PRETTY HIGH TODAY INTO TONIGHT ESPECIALLY OVER RECENT BURN
SCARS AND PLACES THAT HAD HEAVY RAIN AND SOME FLOODING FRIDAY.
HIGH PRESSURE TO OUR NORTHWEST WILL GRADUALLY BUILD TOWARD AND OVER
NEW MEXICO SUNDAY INTO WEDNESDAY. A SLOW TREND DOWNWARD IN SHOWERS
AND STORMS WILL BE THE CASE...WITH THE KEY WORD BEING SLOW...AS LOW
LEVELS TO REMAIN MOIST WHILE MID AND UPPER LEVELS GRADUALLY DRY
OUT.
MODELS TAKE CENTER OF HIGH PRESSURE A LITTLE EAST OF NEW MEXICO FOR
THE END OF NEXT WEEK...WHILE AN EASTERLY WAVE DRIFTING NORTHEAST FROM
MEXICO MAY BEGIN TO IMPACT THE SOUTHWEST PORTIONS OF THE STATE. THIS
WOULD ALLOW FOR A MORE CLASSIC MONSOONAL SURGE OF MOISTURE FOR THE
WEST THURSDAY AND FRIDAY.
MODELS DIVERGE BY NEXT WEEKEND WITH THE GFS KEEPING THE HIGH CENTER
TO OUR EAST WHILE THE EUROPEAN BUILDS THE HIGH BACK OVER AND A
LITTLE WEST OF THE STATE. BOTH MODELS THOUGH BRING COPIOUS AMOUNTS
OF RAIN FOR NEXT WEEKEND AS THE EUROPEAN HAS A BACK DOOR FRONT
BLASTING INTO NEW MEXICO WHILE THE GFS HAS THE EARLIER MENTIONED
EASTERLY WAVE COMING UP THROUGH AZ AND WESTERN NM...WITH A WEAKER
PUSH FROM THE BACK DOOR COLD FRONT.
HIGH TEMPERATURES WILL GRADUALLY WARM THROUGH MIDWEEK WHILE MINIMUM
RH VALUES LOWER. NIGHTTIME RECOVERIES WILL REMAIN MOSTLY GOOD TO
EXCELLENT ASIDE FROM FAIR MOST NIGHTS IN THE NORTHWEST. VENTILATION
WILL BE FAIR OR BETTER FOR THE MOST PART EXCEPT FOR SOME POOR RATES
IN THE NORTHWEST TODAY...RIO GRANDE VALLEY SUNDAY AND WEST TUESDAY.
CHJ
&&
.AVIATION...
06Z TAF CYCLE
A BROAD AREA OF SLOW MOVING SHOWERS AND THUNDERSTORMS OVER NE NM IS
EXPECTED TO DRIFT SLOWLY S AND SSW FOR THE REMAINDER OF THE NIGHT.
MEANWHILE...MODELS DEPICT CONVECTION IN THE W CENTRAL AND SW MTS
GRADUALLY DIMINISHING OR EXITING WESTWARD. HOWEVER...THESE CELLS LOOK
STRONG ENOUGH TO LAST THROUGH AT LEAST 09Z. THE HRRR MODEL...WHICH HAS
BEEN DOING PRETTY GOOD LATELY...ALSO DEPICTS A SMALL CLUSTER OF
CELLS SHIFTING FROM NEAR KSAF SWWD THROUGH THE KABQ/KAEG AREA LATE
TONIGHT. ANOTHER ROUND OF SCT-NMRS STORMS IS EXPECTED SATURDAY
AFTN AND EVENING...WITH THE POTENTIAL FOR MORE HEAVY RAIN...MT
OBSCURATIONS AND HAIL. WITH THE 500 MB HIGH PRESSURE CENTER OVER
NV...THE CONVECTION SHOULD CONTINUE TO TRACK TOWARD THE S...SW AND
W ACROSS NM.
44
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 91 65 93 66 / 30 30 20 30
DULCE........................... 84 52 87 54 / 50 50 40 40
CUBA............................ 83 54 86 54 / 50 50 50 50
GALLUP.......................... 83 59 85 59 / 50 50 40 40
EL MORRO........................ 79 53 79 53 / 60 50 50 50
GRANTS.......................... 82 58 83 58 / 40 50 40 40
QUEMADO......................... 81 56 81 57 / 60 60 50 50
GLENWOOD........................ 82 57 83 58 / 40 40 50 40
CHAMA........................... 79 48 80 50 / 70 60 50 40
LOS ALAMOS...................... 79 60 82 62 / 50 50 50 40
PECOS........................... 73 58 77 60 / 50 60 50 40
CERRO/QUESTA.................... 78 54 80 55 / 60 50 40 40
RED RIVER....................... 71 44 75 44 / 70 60 50 40
ANGEL FIRE...................... 73 43 77 43 / 70 60 50 40
TAOS............................ 81 53 86 54 / 50 50 40 30
MORA............................ 72 54 78 55 / 60 60 50 40
ESPANOLA........................ 83 59 86 60 / 40 40 40 30
SANTA FE........................ 79 59 83 61 / 50 60 50 40
SANTA FE AIRPORT................ 82 60 86 62 / 50 50 40 30
ALBUQUERQUE FOOTHILLS........... 84 65 88 68 / 60 60 40 40
ALBUQUERQUE HEIGHTS............. 85 67 89 70 / 50 50 30 30
ALBUQUERQUE VALLEY.............. 86 65 90 68 / 40 40 30 30
ALBUQUERQUE WEST MESA........... 86 65 90 67 / 40 40 30 40
LOS LUNAS....................... 88 64 89 67 / 40 40 20 30
RIO RANCHO...................... 87 65 91 67 / 40 40 30 30
SOCORRO......................... 92 65 93 66 / 30 30 20 30
SANDIA PARK/CEDAR CREST......... 83 59 86 61 / 60 60 50 40
TIJERAS......................... 81 60 84 63 / 50 60 50 40
MORIARTY/ESTANCIA............... 80 58 83 59 / 50 50 40 40
CLINES CORNERS.................. 79 58 82 60 / 40 50 40 40
GRAN QUIVIRA.................... 80 58 82 60 / 40 40 40 30
CARRIZOZO....................... 82 61 84 64 / 30 30 30 20
RUIDOSO......................... 73 53 74 56 / 50 30 40 30
CAPULIN......................... 79 56 84 58 / 50 50 20 20
RATON........................... 83 57 89 58 / 50 40 30 30
SPRINGER........................ 83 58 88 59 / 40 50 30 20
LAS VEGAS....................... 79 57 83 57 / 50 50 30 30
CLAYTON......................... 87 65 93 66 / 30 30 10 10
ROY............................. 82 63 86 64 / 40 30 10 20
CONCHAS......................... 88 67 92 69 / 20 20 10 10
SANTA ROSA...................... 87 65 91 68 / 20 20 10 10
TUCUMCARI....................... 92 69 95 71 / 20 20 10 10
CLOVIS.......................... 87 64 89 65 / 10 10 5 10
PORTALES........................ 88 65 89 65 / 10 10 5 5
FORT SUMNER..................... 88 67 90 68 / 10 10 10 10
ROSWELL......................... 90 67 92 69 / 10 10 5 10
PICACHO......................... 84 60 86 63 / 20 20 10 10
ELK............................. 77 57 79 59 / 40 30 20 20
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH SUNDAY EVENING FOR THE FOLLOWING ZONES...
NMZ501>529.
&&
$$
34
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1151 PM MDT FRI JUL 19 2013
.AVIATION...
06Z TAF CYCLE
A BROAD AREA OF SLOW MOVING SHOWERS AND THUNDERSTORMS OVER NE NM IS
EXPECTED TO DRIFT SLOWLY S AND SSW FOR THE REMAINDER OF THE NIGHT.
MEANWHILE...MODELS DEPICT CONVECTION IN THE W CENTRAL AND SW MTS
GRADUALLY DIMINISHING OR EXITING WESTWARD. HOWEVER...THESE CELLS LOOK
STRONG ENOUGH TO LAST THROUGH AT LEAST 09Z. THE HRRR MODEL...WHICH HAS
BEEN DOING PRETTY GOOD LATELY...ALSO DEPICTS A SMALL CLUSTER OF
CELLS SHIFTING FROM NEAR KSAF SWWD THROUGH THE KABQ/KAEG AREA LATE
TONIGHT. ANOTHER ROUND OF SCT-NMRS STORMS IS EXPECTED SATURDAY
AFTN AND EVENING...WITH THE POTENTIAL FOR MORE HEAVY RAIN...MT
OBSCURATIONS AND HAIL. WITH THE 500 MB HIGH PRESSURE CENTER OVER
NV...THE CONVECTION SHOULD CONTINUE TO TRACK TOWARD THE S...SW AND
W ACROSS NM.
44
&&
.PREV DISCUSSION...725 PM MDT FRI JUL 19 2013...
BASED ON RADAR TRENDS TODAY AND EXPECTED HEAVY/TORRENTIAL RAIN
POTENTIAL THROUGH THE WEEKEND...DECIDED TO HOIST A FLASH FLOOD
WATCH FOR CENTRAL AND WESTERN NM. PWAT VALUES WILL COME UP EVEN
A LITTLE HIGHER FOR THE REGION AND STEERING FLOW WILL CONTINUE
TO WEAKEN. CONSIDERING IMPACTS FROM STORMS TODAY WE EXPECT VERY
SIMILAR CONDITIONS THROUGH AT LEAST SUNDAY EVENING. FFA ALREADY
ON THE STREET AND PRODUCT UPDATES FOLLOWING SHORTLY.
GUYER
.PREV DISCUSSION...258 PM MDT FRI JUL 19 2013...
ROBUST ROUND OF THUNDERSTORMS ON THE UPTREND AS OF 3PM...MOVING
WSW FROM THE NORTHERN MOUNTAINS AND NE HIGHLANDS/PLAINS. A REPORT
OF 1.54 INCHES IN LESS THAN ONE HOUR CAME IN FROM NEAR 10 MILES
SOUTH OF SANTA FE...SO THESE STORMS ARE CERTAINLY CAPABLE OF
PRODUCING LOCALLY HEAVY RAINFALL. THE 12Z KABQ PWAT WAS 1.27
INCHES...WHICH IS 147 PERCENT OF NORMAL AND CLOSE TO +2 STANDARD
DEVIATIONS ABOVE NORMAL. IN ADDITION TO THE JUICY ATMOSPHERE
OVERHEAD...STORM MOTIONS IS 10 MPH OR LESS WHICH ADDS TO THE
LOCALLY HEAVY RAINFALL THREAT. STORMS APPROACHING THE ABQ METRO
FROM THE NE WILL CERTAINLY HAVE A PRIMED AIRMASS TO WORK OVER...
WITH THE 20Z LAPS ANALYSIS SHOWING SURFACE BASED CAPES AROUND 2000
J/KG AND LIFTED INDICES BETWEEN -4 AND -5C. MAIN IMPACT PERIOD FOR
THE ABQ METRO WILL BE FROM 330 TO 530PM MDT. SHOWERS AND
THUNDERSTORMS WILL PERSIST INTO THE EVENING HOURS...BUT SHOULD
DIMINISH SHORTLY AFTER MIDNIGHT WITH NO SUNRISE SURPRISES SATURDAY
MORNING.
SATURDAY WILL BE SIMILAR OVERALL WITH WELL ABOVE NORMAL PWATS...
BUT SLOWER STORM MOTION TO THE WEST OR SOUTHWEST. LOCALLY HEAVY
RAINFALL AMOUNTS OF 1 TO 2 INCHES WILL BE POSSIBLE AGAIN...
ESPECIALLY OVER THE MOUNTAIN ZONES. SUNDAY WILL BE A TAD
WARMER/DRIER OVERALL AS PRESSURE HEIGHTS INCREASE WITH THE UPPER
HIGH OVER NEVADA RIDGING INTO COLORADO AND NORTHERN NM. SUNDAY`S
CROP OF THUNDERSTORMS WILL LIKELY HUG THE TERRAIN A BIT MORE AS
WELL WITH EVEN LIGHTER STEERING FLOW.
THE FORECAST TRENDS AND CHALLENGES BEYOND MONDAY HAVE NOT CHANGED
THIS FORECAST CYCLE. A GRADUAL TEMPERATURE UPTREND AND CONVECTIVE
DOWNTREND IS FORECAST NEXT WEEK AS THE UPPER HIGH MOVES SLOWLY ESE
ACROSS NM AND INTO TEXAS. SOME DIFFERENCES ARE STILL SHOWING UP IN
THE PLACEMENT OF THE UPPER HIGH CENTROID BY FRIDAY OF NEXT
WEEK...WITH THE ECMWF STILL SHOWING IT EAST OF NM. SO AT SOME
POINT LATE NEXT WEEK...OR POSSIBLY DELAYED UNTIL THE
WEEKEND...TEMPERATURES WILL TREND BACK DOWN AND RAIN CHANCES WILL
TREND BACK UP AS A MORE TRADITIONAL MONSOON PATTERN SETS UP. THAT
SAID...LOW FORECAST CONFIDENCE BEYOND WEDNESDAY AT THIS TIME.
11
.FIRE WEATHER...
ISOLATED SHOWERS AND THUNDERSTORMS EXPECTED TO CONTINUE TONIGHT WITH
A JUICY AIRMASS IN PLACE AND SOME WEAK ATMOSPHERIC LIFT REMAINING
OVER THE AREA. BACK DOOR COLD FRONT OVER NE PLAINS AND HIGHLANDS
WILL KEEP A FEW STRONG STORMS GOING THERE UNTIL AROUND MIDNIGHT
ALONG WITH ISOLATED SHOWERS THROUGH THE EARLY MORNING. PARTIAL
CLEARING MAY INHIBIT OVERNIGHT RELATIVE HUMIDITY RECOVERIES SLIGHTLY
BUT STILL EXPECTING VERY GOOD TO EXCELLENT RECOVERY VALUES MOST
PLACES BY EARLY MORNING SATURDAY WITH WIDESPREAD WETTING RAINS.
ANOTHER ACTIVE TO VERY ACTIVE DAY IN STORE SATURDAY WITH THE UPPER
LEVEL WEATHER PATTERN CHANGING LITTLE AND PLENTY OF MOISTURE IN
PLACE...POSSIBLY INCREASING SOMEWHAT MORE WITH A WEAK TO MODERATE
SOUTHERLY SURFACE FLOW DEVELOPING.
PREVIOUS WEATHER PREDICTION MODEL INDICATIONS WERE THAT A DOWNTREND
IN CONVECTION WOULD BEGIN SUNDAY AS THE DEEPER MOISTURE HEADED
WESTWARD INTO ARIZONA. LATEST DATA...HOWEVER...SUGGESTS THAT THIS
MAY NOT BE THE CASE. WHILE SOME DRIER AIR ALOFT BEGINS TO FILTER IN
FROM THE NORTHEAST...PLENTY OF LOW AND MID LEVEL MOISTURE EXPECTED
TO CONTINUE TO PUSH UP FROM SOUTH FROM DECAYING CONVECTIVE COMPLEXES
OVER NORTHERN OLD MEXICO SUNDAY MORNING.
ANOTHER ACTIVE DAY IN STORE MONDAY AS THE UPPER HIGH MOVES LITTLE
AND PLENTY OF LOW LEVEL MOISTURE LEFT IN PLACE TO RECYCLE. AT THIS
POINT IN TIME...TUESDAY APPEARS TO BE THE FIRST OF SEVERAL DOWN DAYS
AS VERY DRY AIR ALOFT BEGINS TO MOVE IN FROM THE EAST/SE.
GENERAL TREND OF THE MEDIUM RANGE MODELS IS TO SHIFT THE FOUR
CORNERS HIGH SLOWLY EASTWARD WEDNESDAY NIGHT INTO
THURSDAY...ALLOWING FOR A CLASSIC SOUTHERLY MONSOONAL FLOW. BOTH
ECMWF AND GFS INDICATING THAT AN EASTERLY WAVE MAY ALSO GET INTO THE
MIX...MOVING UP INTO SW AZ THURSDAY NIGHT AND FRIDAY...ENHANCING THE
DEEP SOUTHERLY MONSOONAL FLOW OVER NM TOWARD THE END OF THE WORK
WEEK.
33
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH SUNDAY EVENING FOR THE FOLLOWING ZONES...
NMZ501>529.
&&
$$
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
409 AM EDT SAT JUL 20 2013
.SYNOPSIS...
A TYPICAL SUMMER PATTERN OF HIGH PRESSURE OFFSHORE AND A TROUGH
OF LOW PRESSURE INLAND WILL PERSIST THROUGH THE WEEKEND. A COLD
FRONT WILL MOVE INTO THE AREA BY WEDNESDAY OR THURSDAY OF NEXT WEEK.
&&
.NEAR TERM /TODAY/...
AS OF 355 AM SATURDAY...BAND OF SHOWERS MOVING UP THE COAST THIS
MORNING...WHICH WAS WELL DEPICTED BY THE HRRR AND A NUMBER OF
OTHER HIGH RESOLUTION MODELS. THIS ACTIVITY SHOULD LINGER NEAR OR
JUST OFFSHORE THROUGH THE EARLY MORNING HOURS BEFORE TRANSITIONING
INLAND AS SOME ADDITIONAL MID-LEVEL ENERGY MOVES NORTHEAST AROUND
THE PERIPHERY OF BROAD BERMUDA RIDGE TO THE EAST AND SURFACE
TROUGH OVER THE PIEDMONT SHARPENS DURING THE AFTERNOON. ADDITIONAL
SHOWERS/TSTMS WILL DEVELOP DURING THE MID TO LATE AFTERNOON HOURS
WITH THE FAVORED LOCATION BEING THE SOUTHERN COASTAL PLAINS AND
SOUTHERN COASTAL AREAS. IT WILL BE ANOTHER WARM AND HUMID DAY WITH
HIGHS IN THE UPPER 80S TO LOWER 90S IN MOST AREAS.
&&
.SHORT TERM /TONIGHT/...
AS OF 400 AM SATURDAY...NOT ALOT OF CHANGE TO THE FORECAST
TONIGHT. THE COMBINATION OF DEEP MOISTURE AND ADDITIONAL
SHORTWAVE ENERGY EMBEDDED IN SOUTHWEST FLOW WILL LEAD TO A LOW
CHANCE POPS THROUGH THE NIGHT TONIGHT. MINIMUM TEMPERATURES
TONIGHT SHOULD BE IN THE 73 TO 77 DEGREE RANGE.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
AS OF 315 AM SAT...SW FLOW PERSISTS SAT NIGHT INTO SUN WITH
DEWPOINTS/PWATS RISING. SHORT TERM MODELS CONTINUE IN DECENT
AGREEMENT ON POTENTIAL FOR SHOWERS/TSTORMS RIDING UP THE COAST
EARLY SUN AS AREA OF CONVERGENCE EXISTS WITH WEAK SHORTWAVE
ENERGY MOVING NORTHEAST FROM OFF CHS/ILM TOWARDS THE CWA. WILL
MAINTAIN SLIGHT CHANCE POPS FOR COASTAL AREAS WITH CHANCE POPS
JUST OVER THE WATERS. PRECIP CHANCES INCREASE SUN AFTERNOON AS A
WEAK COOL FRONT APPROACHES AND SETTLES OVER EASTERN NC BEFORE
WASHING OUT LATER IN THE WEEK.
UPPER TROUGH OVER THE GREAT LAKES WILL DIG SOUTH MON/TUES AND
PERSIST OVER THE EASTERN CONUS THROUGH LATE WEEK...REINFORCING THE
RAIN CHANCES THROUGH THE PERIOD. WEAK PERTURBATIONS IN THE MID AND
UPPER LEVELS WILL ALSO AID CONVECTION DURING THE EXTENDED PERIOD.
PWATS INCREASE TO 2 INCHES OR GREATER SUN AND REMAIN HIGH THROUGH
MID TO LATE WEEK. HAVE CONTINUED THE TREND OF DIURNAL CONVECTION
EACH DAY WITH NEAR 50 PERCENT POPS INLAND DURING THE AFTERNOON
WITH 25-30 PERCENT POPS OVERNIGHT...WITH THIS PATTERN EXPECTED
THROUGH LATE WEEK. SEVERE WEATHER IS NOT EXPECTED AS SHEAR WILL BE
MINIMAL...THOUGH WITH ANY PULSE STORM AN ISOLATED STRONG TO SEVERE
WIND GUST IS POSSIBLE. WITH OVERALL WEAK STEERING FLOW...ANY
ORGANIZED CONVECTION WILL HAVE HEAVY RAINFALL POTENTIAL ESPECIALLY
IF CELLS TRAIN OVER THE SAME AREA. WILL HAVE TO WATCH OUT FOR
LOCALIZED FLOODING AS THIS UNSETTLED PATTERN LOOKS TO PERSIST.
TEMPS THROUGH THE LONG TERM PERIOD WILL BE CLOSER TO CLIMO...HIGHS
IN THE UPPER 80S TO NEAR 90 WITH LOW/MID 70S FOR OVERNIGHT LOWS.
&&
.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM /TODAY AND TONIGHT/...
AS OF 1245 AM SATURDAY...THERE APPEARS TO BE SUFFICIENT MIXING
OVERNIGHT TO PRECLUDE MUCH IN THE WAY OF FOG OR STRATUS AS WE KEEP
A LIGHT SOUTHWEST WIND OVERNIGHT. SLIGHTLY BETTER CHC OF TSTMS
INLAND SAT AFTN WITH CONTINUED INFLUX OF MSTR AND WEAK SHRT WV
ENERGY FROM S-SW. SW WINDS MAY GUST UP TO 20 KTS AS WELL DURING
AFTN.
LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 4 AM SAT...PREDOMINANT VFR CONDITIONS EXPECTED THROUGH
THE PERIOD. AN UPPER TROUGH AND ASSOCIATED SFC FRONT APPROACH
FROM THE NW SUN BRINGING INCREASING CHANCES OF SCATTERED
SHOWERS/TSTORMS FOR THE TERMINALS THROUGH LATE WEEK. COULD SEE
BRIEF EARLY MORNING MVFR/IFR VSBYS DURING THE LONG TERM AS
FORECAST SOUNDINGS INDICATE GOOD BOUNDARY LAYER MOISTURE TRAPPED
UNDER A WEAK SURFACE BASED INVERSION. HOWEVER...BOUNDARY LAYER
MIXING MAY BE ENOUGH TO INHIBIT FOG FORMATION...THUS LOW
CONFIDENCE IN REDUCED AVIATION CONDITIONS EACH NIGHT.
&&
.MARINE...
SHORT TERM /TODAY AND TONIGHT/...
AS OF 4 AM SATURDAY...HAVE ADDED THE CURRITUCK BEACH LIGHT TO
OREGON INLET LEG TO THE SMALL CRAFT ADVISORY AND HAVE MADE THE
EFFECTIVE TIME NOW AS LATEST OBSERVATIONS SHOWING WIND GUSTS AS
HIGH AS 25 KNOTS AT DUCK AND UP TO 29 KNOTS AT OREGON INLET. EVEN
SEEING WINDS AS HIGH AS 25 KNOTS IN THE PAMLICO SOUND. THE GUSTY
SW WINDS WILL CONTINUE TODAY BEFORE SUBSIDING A BIT TONIGHT. SEAS
WILL REMAIN AS HIGH AS 6 FEET PER LATEST WAVEWATCH BEFORE
SUBSIDING LATE TONIGHT OR EARLY SUNDAY MORNING.
LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 330 AM SAT...HIGH PRESSURE OFF THE SE COAST WITH A THERMAL
TROUGH INLAND WILL BE THE DOMINANT PATTERN THROUGH MUCH OF THE
LONG TERM. PRESSURE GRADIENT REMAINS TIGHT THROUGH EARLY SUNDAY
BEFORE WEAKENING DUE TO APPROACHING COOL FRONT DISSIPATING INLAND.
SCA CONDITIONS SHOULD DIMINISH ACROSS THE COASTAL WATERS BY SUN
AFTERNOON AS SEAS SUBSIDE BELOW 6 FEET. A BREAK IN THE GUSTY SW
WINDS MONDAY BEFORE REINFORCING TROUGH/FRONT APPROACH TUES INTO
MID WEEK. MARGINAL SCA CONDITIONS COULD DEVELOP ONCE AGAIN AS THE
GRADIENT INCREASES TUES NIGHT. NO SIGNIFICANT CHANGES TO THE
MEDIUM TERM...BUT HAVE ADJUSTED SEAS DOWN A FOOT FROM WED NIGHT
THROUGH THURS NIGHT...WHICH IS IN COLLABORATION WITH NEIGHBORING
OFFICES AND OPC.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO NOON EDT SUNDAY FOR
AMZ152-154-156-158.
SMALL CRAFT ADVISORY FROM NOON TODAY TO 10 PM EDT THIS EVENING
FOR AMZ135.
&&
$$
SYNOPSIS...CTC
NEAR TERM...CTC
SHORT TERM...CTC
LONG TERM...DAG
AVIATION...CTC/DAG
MARINE...CTC/DAG
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
1250 AM EDT SAT JUL 20 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN EAST OF THE AREA WITH TROUGHING TO THE
WEST THROUGH THE WEEKEND AND INTO MIDWEEK. A FRONT WILL APPROACH
LATER IN THE WEEK BUT NOT MOVE THROUGH.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1240 AM SATURDAY...DECENT AGREEMENT AMONGST THE 4 KM EMC
WRF...HRR-R AND RAP MODELS SHOWING SOME WIDELY SCATTERED SHOWERS
AND TSTMS DEVELOPING ALONG THE SOUTHERN COAST AFTER 08Z. THE NAM
IS A BIT SLOWER IN THE DEVELOPMENT OF CONVECTION...BUT DOES SHOW T
THE PRECIPITATION AREA SPREADING NORTH AND WEST DURING THE
MORNING AS SOME MID-LEVEL ENERGY MOVES UP THE COAST AROUND THE
PERIPHERY OF LARGE BERMUDA HIGH. HAVE KEPT SLIGHT TO LOW CHC POPS
RIGHT ALONG THE IMMEDIATE COAST THROUGH 12Z. WHILE COVERAGE WILL
NOT BE PARTICULARLY GREAT...THERE IS SUFFICIENT INSTABILITY AND
MOISTURE TO HAVE SOME LOCALIZED DOWNPOURS...PARTICULAR THE
SOUTHERN COAST AND SOUTHERN COASTAL PLAINS. NO CHANGES TO
OVERNIGHT TEMP FORECAST.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SUNDAY/...
AS OF 400 PM FRI...DESPITE GENERAL AGREEMENT IN THE OVERALL
PATTERN THERE ARE SEVERAL DIFFERENCES IN THE MODELS REGARDING
TIMING AND LOCATION OF APPROACHING SHRTWV ENERGY AND
PRECIPITATION. SETTLED ON A COMPROMISE SOLUTION BETWEEN THE 12Z
GFS AND 12Z NAM SIMILAR TO THE 00Z ECMWF. EXPECT A CHANCE OF
PRECIPITATION TO DEVELOP ALONG THE SOUTHEAST COAST LATE TONIGHT
INTO TOMORROW MORNING...THEN SHIFTED THE FOCUS FOR ANY SHOWERS AND
TSTMS INLAND ALONG THE SEA BREEZE FOR SATURDAY AFTERNOON. MOS
GUIDANCE WAS IN CLOSE AGREEMENT AND FOLLOWED A BLEND THROUGH THE
PERIOD.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
AS OF 330 PM FRI...SW FLOW INCREASES SAT NIGHT WITH DEWPOINTS/PWATS
ON THE RISE. MOST SHORT TERM MODELS IN AGREEMENT ON POTENTIAL FOR
SHOWERS/STORMS RIDING UP THE COAST SAT NIGHT AS AREA OF
CONVERGENCE EXISTS WITH WEAK SHORTWAVE ENERGY MOVING NORTHEAST.
HAVE MAINTAINED SLIGHT CHANCE POPS FOR COASTAL AREAS WITH CHANCE
POPS JUST OVER THE WATERS.
PRECIP CHANCES INCREASE SUN AS A WEAK COOL FRONT APPROACHES AND
SETTLES OVER EASTERN NC BEFORE WASHING OUT MIDWEEK. HOWEVER... IT
APPEARS THAT UNSETTLED WEATHER WILL EXIST MID WEEK AND BEYOND AS
LATEST TREND IN MODELS INDICATE PERSISTENT LONG WAVE TROUGHINESS
ACROSS THE EASTERN CONUS REINFORCING THE RAIN CHANCES. HAVE INC
POPS TO HIGH CHANCE MID WEEK DUE TO THESE LATEST TRENDS.
FOR SUNDAY...APPROACHING WEAK COOL FRONT ALONG WITH WEAK
PERTURBATIONS IN THE MID AND UPPER LEVELS WILL SPARK SCT MAINLY
AFTERNOON AND EARLY EVENING CONVECTION...WITH BEST CHANCES ACROSS
INLAND LOCALES. SEVERE WEATHER NOT EXPECTED AS SHEAR IS
MINIMAL...THOUGH WITH ANY PULSE STORM AN ISOLATED STRONG TO SEVERE
WIND GUST IS POSSIBLE. THE SAME HOLDS TRUE FOR THE REST OF THE
UPCOMING WEEK WITH ANY AFTERNOON CONVECTION. UPPER TROUGH OVER
THE GREAT LAKES WILL DIG SOUTH MON/TUES AND PERSIST OVER THE
EASTERN CONUS THROUGH LATE WEEK. PWATS INCREASE TO 2 INCHES OR
GREATER LATE THIS WEEKEND AND REMAIN HIGH THROUGH MID TO LATE WEEK.
WITH OVERALL WEAK STEERING FLOW...ANY ORGANIZED CONVECTION WILL
HAVE HEAVY RAINFALL POTENTIAL ESPECIALLY IF CELLS TRAIN OVER THE
SAME AREA. WILL HAVE TO WATCH OUT FOR LOCALIZED FLOODING AS THIS
UNSETTLED PATTERN LOOKS TO PERSIST. TEMPS THROUGH THE LONG TERM
PERIOD WILL BE CLOSER TO CLIMO...HIGHS IN THE UPPER 80S TO NEAR 90
WITH LOW/MID 70S FOR OVERNIGHT LOWS.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM /THROUGH 00Z SUNDAY/...
AS OF 1245 AM SATURDAY...THERE APPEARS TO BE SUFFICIENT MIXING
OVERNIGHT TO PRECLUDE MUCH IN THE WAY OF FOG OR STRATUS AS WE KEEP
A LIGHT SOUTHWEST WIND OVERNIGHT. SLIGHTLY BETTER CHC OF TSTMS
INLAND SAT AFTN WITH CONTINUED INFLUX OF MSTR AND WEAK SHRT WV
ENERGY FROM S-SW. SW WINDS MAY GUST UP TO 20 KTS AS WELL DURING
AFTN.
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 330 PM FRI...PREDOMINANT VFR CONDITIONS EXPECTED THROUGH
THE PERIOD. COULD SEE MVFR/IFR VSBYS DURING THE EARLY MORNING
HOURS AS FORECAST SOUNDINGS INDICATE GOOD MOISTURE TRAPPED UNDER
THE SURFACE BASED INVERSION WITH LIGHT WINDS...ESPECIALLY FOR AREAS
THAT RECEIVE RAINFALL DURING THE DAY. AN UPPER TROUGH AND ASSOCIATED
SFC FRONT APPROACH FROM THE NW SUN BRINGING INCREASING CHANCES OF
SCATTERED SHOWERS/TSTORMS FOR THE TERMINALS THROUGH MID TO LATE WEEK.
&&
.MARINE...
SHORT TERM /THROUGH SATURDAY/...
AS OF 1245 AM SATURDAY...MODERATE SW WINDS CONTINUE OVER THE
COASTAL WATERS WITH GUSTS INTO THE LOWER 20S IN MANY AREAS. SEAS
CONTINUE AT 1 TO 3 FEET NORTH AND UP TO 4 FEET SOUTHERN WATERS.
WILL MONITOR TRENDS TO SEE IF SCA NEED TO BE STARTED EARLIER.
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 330 PM FRI...HIGH PRESSURE OFF THE SE COAST WITH A THERMAL
TROUGH INLAND WILL BE THE DOMINANT PATTERN THROUGH MUCH OF THE
LONG TERM. PRESSURE GRADIENT REMAINS TIGHT THROUGH EARLY SUNDAY
BEFORE WEAKENING DUE TO APPROACHING COOL FRONT WASHING OUT AND
DISSIPATING. SCA CONDITIONS SHOULD DIMINISH FOR PAMLICO SOUND SAT
NIGHT... WITH COASTAL WATERS SEEING IMPROVING CONDITIONS BY SUN
AFTERNOON AS SEAS SUBSIDE BELOW 6 FEET. A BREAK IN THE GUSTY SW
WINDS MONDAY BEFORE REINFORCING TROUGH/FRONT APPROACH TUE INTO MID
WEEK. MARGINAL SCA CONDITIONS COULD DEVELOP ONCE AGAIN AS THE
GRADIENT INCREASES.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO NOON EDT SUNDAY FOR
AMZ152-154-156-158.
SMALL CRAFT ADVISORY FROM NOON TODAY TO 10 PM EDT THIS EVENING
FOR AMZ135.
&&
$$
SYNOPSIS...CGG
NEAR TERM...CTC
SHORT TERM...CGG
LONG TERM...DAG/TL
AVIATION...CTC/DAG/TL
MARINE...CTC/DAG/TL/BM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
110 AM CDT SAT JUL 20 2013
.UPDATE...
ISSUED AT 109 AM CDT SAT JUL 20 2013
OVERALL THE INHERITED FORECAST IS ON TRACK AND BLENDED TO THE
06 UTC OBSERVATIONS...WITH THE 04 UTC HRRR WEIGHTED HEAVILY FOR
POPS FOR THE REMAINDER OF THE NIGHT GIVEN ITS GOOD HANDLING OF
CONVECTIVE COVERAGE AND EVOLUTION THE PAST FEW HOURS.
UPDATE ISSUED AT 903 PM CDT FRI JUL 19 2013
LATEST RADAR IMAGERY CONTINUES TO SHOW SCATTERED THUNDERSTORMS
STRETCHED FROM NORTHWEST TO SOUTHEAST ALONG AND AHEAD OF A COLD
FRONT. BASED ON THE 3HR PRESSURE CHANGE...THIS FRONT WOULD ROUGHLY
FOLLOW ALONG A WATFORD CITY TO HAZEN...AND INTO STEELE AND
EDGELEY. SEVERAL OUTFLOWS EVIDENT WHICH MAY PRODUCE MORE
CONVECTION ACROSS SOUTH CENTRAL NORTH DAKOTA THROUGH THE EVENING
AND OVERNIGHT...WHICH IS WHAT THE HRRR INDICATES AS WELL. SEVERE
THREAT LOOKS TO REMAIN ISOLATED BUT WILL NEED TO CLOSELY MONITOR.
UPDATE ISSUED AT 659 PM CDT FRI JUL 19 2013
LATEST 3HR PRESSURE CHANGE SHOWS A COLD FRONT NEAR/ALONG OUR
NORTHERN BORDER SLOWLY PUSHING SOUTH. SCATTERED THUNDERSTORMS
CONTINUE TO DEVELOP ALONG AND AHEAD OF THE FRONT AS THEY MOVE
SOUTHEAST WITH TIME. LATEST HRRR/HIGH RESOLUTION RAPID REFRESH MODEL
SHOWS FIRST AREA OF SHOWERS AND THUNDERSTORMS IN NORTH CENTRAL
NORTH DAKOTA MOVING INTO THE JAMES RIVER VALLEY THROUGH 05Z
SATURDAY. THE OTHER ITEM OF INTEREST ARE THE SHOWERS AND
THUNDERSTORMS IN NORTHEAST MONTANA WHICH ARE FORECAST TO REACH
KBIS BY AROUND 07Z. EXPECTING ISOLATED SEVERE THUNDERSTORMS TO
CONTINUE THROUGH THE EVENING.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 306 PM CDT FRI JUL 19 2013
SHORT TERM CONCERNS INVOLVE THUNDERSTORMS NORTH CENTRAL ASSOCIATED
WITH A CANADIAN COLD FRONT SLIDING SOUTH ACROSS THE REGION. CAPE
VALUES SHOW POTENTIAL FOR STRONG THUNDERSTORMS BUT MID LEVEL LAPSE
RATES AROUND 5 TO 6 DEGREES SHOULD LIMIT THE SEVERE POTENTIAL.
HOWEVER THE POTENTIAL FOR SOME HAIL AND GUSTY WINDS EXISTS THIS
EVENING. EXPECT SOME DIURNAL MINIMUM TONIGHT FOR THE STORMS...AND
SCATTERED THUNDERSTORMS ALONG THE FRONTAL ZONE SOUTH CENTRAL AND
WEST SATURDAY.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 306 PM CDT FRI JUL 19 2013
H5 PATTERN PER GFS/ECMWF CONTINUES WITH MOSTLY A NORTHWEST FLOW
ALOFT THROUGH THE PERIOD. PERIODIC UPPER DISTURBANCES IN COMBINATION
WITH INSTABILITY AND DYNAMICAL PARAMETERS IN PLACE WILL ALLOW FOR A
CHANCE OF SHOWERS AND/OR THUNDERSTORMS ALMOST EVERYDAY...WITH THE
EXCEPTION OF MONDAY...WHERE A DRY DAY IS FORECAST.
FOR SATURDAY NIGHT AND SUNDAY...MAIN HIGHLIGHT HERE IS A MORE
SIGNIFICANT SHORTWAVE MOVING THROUGH SOUTHERN SASKATCHEWAN SUNDAY
MORNING AND INTO SOUTHERN MANITOBA BY SUNDAY AFTERNOON. A SURFACE
COLD FRONT WILL BE ASSOCIATED WITH THE SHORTWAVE ALOFT AS IT SLIDES
FROM WEST TO EAST SUNDAY AFTERNOON AND EVENING. BEST FORCING/OMEGA
RESIDES IN THE NORTH CENTRAL SUNDAY AFTERNOON THEN SHIFTS INTO EAST
CENTRAL NORTH DAKOTA SUNDAY EVENING. VERTICAL MOTION IS ENHANCED BY
THE LEFT EXIT REGION OF A 60KT H3 JET STREAK ACROSS THE
AFOREMENTIONED AREA. GFS SHOWS ENOUGH CAPE AND 0-6KM SHEAR OF 45KT
TO 50KT FOR ORGANIZED STORMS WHICH WILL FAVOR SOME SEVERE
THUNDERSTORMS NORTH CENTRAL THROUGH EAST CENTRAL SUNDAY AFTERNOON
THROUGH SUNDAY EVENING. SPC DAY 3 OUTLOOK HAS THE ABOVE AREA IN A
SEE TEXT WITH HAIL AND WIND AS THE PRIMARY THREATS. H85 TEMPS RISE
TO BETWEEN +26C TO +28C IN THE WARM SECTOR SUNDAY AFTERNOON WEST PER
NAM/GFS...HIGHS WILL TOP OUT AROUND 90 OR LOWER 90S. HAVE INCREASED
TEMPS TO REFLECT THIS...HOWEVER DID NOT GO AS WARM AS THE NAM MOS
WANTED DUE TO SOME CLOUD COVER HOLDING TEMPS BACK IN THE MORNING TO
EARLY AFTERNOON. SHOULD BE A QUICK RISE THEREAFTER.
MONDAY...BEHIND THE COLD FRONT...GFS SOUNDINGS SHOW LOW LEVEL COLD
AIR ADVECTION WITH NEUTRAL ADVECTION ALOFT WILL YIELD A COOLER/DRIER
DAY WITH HIGHS IN THE UPPER 70S NORTH TO UPPER 80S SOUTH.
FOR TUESDAY THROUGH FRIDAY...ADDITIONAL SHORTWAVES EMBEDDED IN THE
NORTHWEST FLOW WILL INTERACT WITH THE AFTERNOON/EVENING INSTABILITY
AND SOME JET FORCING AT TIMES TO INITIATE A CHANCE OF
SHOWERS/THUNDERSTORMS.
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 109 AM CDT SAT JUL 20 2013
OUTSIDE OF THUNDERSTORMS TONIGHT...VFR CONDITIONS ARE FORECAST FOR
THE 06 UTC TAF CYCLE. ISOLATED TO SCATTERED THUNDERSTORMS ARE
POSSIBLE AT KISN...KDIK...KMOT AND KBIS THROUGH THE OVERNIGHT AND
CODED AS VCTS FOR NOW AND WILL AMEND BASED ON RADAR TRENDS.
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
$$
UPDATE...AYD
SHORT TERM...WAA
LONG TERM...KS
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
433 AM EDT SAT JUL 20 2013
.SYNOPSIS...
A WEAK SHORTWAVE ALOFT WILL COMBINE WITH DIURNAL HEATING AND
ABUNDANT MOISTURE FOR AFTERNOON AND EVENING CONVECTION. A COLD
FRONT WILL PUSH SOUTHEAST INTO SOUTHERN WEST VIRGINIA SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
CODED CATEGORICAL POPS WITH THE INCOMING H5 VORTICITY MAXIMUM
ASSOCIATED WITH BROAD LOW PRESSURE SYSTEM WAY NORTH IN CANADA.
LOBES OF VORTICITY AT H5 WILL RIDE AROUND THE PERIPHERY TODAY
PROVIDING SOME DYNAMIC LIFT. PWATS WILL INCREASE FROM 1.5 TO 2
INCHES BY THIS EVENING ACROSS THE LOWLANDS. THIS SHORTWAVE SEEMS
TO DIMINISH IN INTENSITY OR SLOWS DOWN ACROSS NORTHERN HALF OF WV.
THIS SCENARIO COULD PRODUCE HEAVY DOWNPOURS CAPABLE TO PRODUCE
FLASH FLOODING. THEREFORE...ISSUED A FLASH FLOOD WATCH FOR THE
NORTHERN HALF OF THE AREA THROUGH SUNDAY AFTERNOON.
THE FOCUS OF THE CONVECTION IS EXPECTED EARLY TONIGHT ACROSS
CENTRAL WV...THEN SLOWLY MOVE SOUTH AND EAST TO AFFECT THE
SOUTHERN PORTIONS. THERE ARE SOME UNCERTAINTY WHERE THE BOUNDARY
WILL STALL ATTM.
THERE IS A SLIGHT RISK OF SEVERE WEATHER AT BOTH SIDES OF THE OH
RIVER...INCLUDING NORTH CENTRAL WEST VIRGINIA.
WENT WITH TEMPERATURES CLOSER TO THE BIAS CORRECTED MET GUIDANCE
THROUGH THE PERIOD.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
MODELS AGREE THE FRONT WILL BE STALLED ACROSS THE CENTRAL OR
NORTHERN PORTIONS OF THE AREA SUNDAY...THEN SLOWLY LIFT BACK NORTH
SUNDAY NIGHT INTO MONDAY...AND FINALLY BE WELL NORTH OF THE AREA BY
MONDAY NIGHT. OUR AREA WILL ALSO BE ON THE SOUTHERN EDGE OF THE
WESTERLIES ALOFT. EMBEDDED SHORT WAVES MOVING OVER THE WARM AND
SOUPY AIRMASS WILL CONTINUE A HIGH THREAT FOR SHOWERS AND
THUNDERSTORMS RIGHT THROUGH TUESDAY. IN THIS PATTERN...TRACKING AND
TIMING OF THESE SHORT WAVES WILL BE DIFFICULT TO EXACTLY DETERMINE
THE CONVECTION SCENARIO. SO...WILL CONCENTRATE CONVECTION SUNDAY AND
SUNDAY NIGHT IN THE CENTRAL AND SOUTH JUST AHEAD OF THE
FRONT...SHIFTING INTO NORTHERN AREAS MONDAY AS THE FRONT LIFTS BACK
NORTH. ON TUESDAY...WILL COAT A HIGH CHANCE EVERYWHERE...EVEN WITH
THE FRONT NORTH OF THE AREA...AS THE MODELS DEPICT A FAIRLY STRONG
AND MORE SYNOPTIC SCALE SHORT WAVE IN THE FLOW. EXCEPT FOR POSSIBLY
THE NORTHERN AREAS SEEING A BRIEF DECREASE IN THE HEAT AND HUMIDITY
SUNDAY...WE LOOK FOR THE WARMTH AND MUGGIES TO DOMINATE RIGHT
THROUGH TUESDAY.
SO THE FLASH FLOOD HAZARD REMAINS WITH US DURING THIS SHORT TERM.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
WITH THE MEAN 500 MB TROF NOT PASSING UNTIL ABOUT THURSDAY...THE
UNSETTLED WEATHER CONTINUES.
NEXT MID LEVEL DISTURBANCE MOVING UP OHIO VALLEY FIGURED FOR AROUND
LATE TUESDAY NIGHT INTO WEDNESDAY....SO HIGHER POPS THEN.
TRIED TO KEEP MAXIMUM TEMPERATURES A BIT LOWER THAN GUIDANCE...WHILE
MINIMUM TEMPERATURES A BIT HIGHER THAN GUIDANCE.
HOPEFULLY SOME DRIER AIR FINALLY REACHING US ABOUT DAY 7.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
STARTING WITH VFR CONDITIONS AT ALL SITES WITH SKIES CLEARING FROM
WEST AND NORTH TOWARDS THE CENTRAL MOUNTAINS. AREAS OF IFR/LIFR
FOG EXPECTED TO DEVELOP QUICKLY AT CRW WITH DEWPOINT DEPRESSION OF
2 AND ASSOCIATED RIVER VALLEY FOG AS THE SKIES CLEARS.
ALTO CIRRUS COVERING EKN AND CKB ATTM. EXPECT CIRRUS TO THIN OUT
AND CLEAR FOR POSSIBLE IFR/LIFR DENSE FOG AT EKN AND OTHER
PROTECTED AREAS. CKB COULD STAY MVFR WHERE CONFIDENCE IS LOWER.
BKW SITE SHOULD CONTINUE TO HAVE A BREEZE PREVENTING FOG FORMATION
AS WELL AS OTHER ELEVATED AREAS. NAM MODEL SHOW BOUNDARY LAYER
WIND ABOUT 15 KNOTS WHILE THE RUC13 SHOWS 5 TO 10 KNOTS. SO A
LITTLE CAUTIONS ON FOG CONDITIONS AT ELEVATED SOURCES.
OVERNIGHT TONIGHT...MODELS SHOW A WEAK ENERGY IN THE MID LEVELS
ARRIVING TO SOUTHEAST OH BY 12Z SATURDAY. UNCERTAIN IF CONVECTION
WILL FORM OVERNIGHT ACROSS SOUTHEAST OH. ALTHOUGH WITH THE WEAK
SHORTWAVE PASSING AND A BUBBLE OF RICH THETA-E IN OVER
OH...UNDER SOUTHWEST FLOW IN BOUNDARY LAYER AND WEAK FLOW ALOFT AT
H5.
ANY IFR/LIFR SHOULD QUICKLY LIFT BY 13Z OR EARLIER AT OTHER SITES
THAN CRW...WHICH SHOULD IMPROVE TO MVFR BY 14Z...AND THEN TO VFR
AFTER WARDS. IFR CONDITIONS EXPECTED UNDER AFTERNOON CONVECTION
SATURDAY. SEEMS LIKE A LINE OF THUNDERSTORMS COULD DEVELOP AND
AFFECT MOST SITES AT THE END OF THE PERIODS..
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SUNDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: DENSITY AND TIMING OF FOG MAY VARY TONIGHT.
SYSTEM COULD MATERIALIZE SOUTHEAST OH BY 12Z SATURDAY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE SAT 07/20/13
UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19
EDT 1HRLY 04 05 06 07 08 09 10 11 12 13 14 15
CRW CONSISTENCY L L L L L H H H H H H H
HTS CONSISTENCY L L L L L L H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY L L L L L L H H H H H H
PKB CONSISTENCY L L L L L L H H H H H H
CKB CONSISTENCY M M M M M M H H H H H H
AFTER 06Z SUNDAY...
IFR POSSIBLE IN ANY CONVECTION. IFR ALSO POSSIBLE IN LOW CEILINGS
EACH MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FLASH FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH SUNDAY
AFTERNOON FOR WVZ007>011-014>020-027>032-037>040-046-047.
OH...FLASH FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH SUNDAY
AFTERNOON FOR OHZ066-067-075-076-083>086.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...FB/JMV/MZ
NEAR TERM...ARJ
SHORT TERM...JMV
LONG TERM...KTB
AVIATION...ARJ/26
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
313 AM EDT SAT JUL 20 2013
.SYNOPSIS...
UPPER HIGH PRESSURE DISSIPATING AS UPPER TROUGH APPROACHES GREAT
LAKES. A COLD FRONT SAGS SLOWLY SOUTHWARD INTO THE AREA THIS
WEEKEND...AND LIFTS BACK NORTH AS A WARM FRONT EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATED SKIES...POPS...AND WEATHER THROUGH SATURDAY PER LATEST
MODEL RUNS...RADAR...AND SATELLITE IMAGES. REST OF FORECAST
REMAINS REPRESENTATIVE.
PREVIOUS DISCUSSION BELOW...
STRATIFORM RAIN LEFT FROM THE CONVECTION TONIGHT. SHOULD DISSOLVE
OUT OVER THE NEXT COUPLE OF HOURS.
FOCUS THEN TURNS TO THE CONVECTION LATER TONIGHT. LOCAL MODELS
BRING THE RENEWED ACTIVITY LATE TONIGHT INTO THE SOUTHEAST OHIO
COUNTIES BY 12Z. THIS IS AHEAD OF THE LINE OF CONVECTION CURRENTLY
WORKING THROUGH THE SOUTHERN GREAT LAKES AREA...ALTHOUGH IT COULD
ALSO DEVELOP FROM THE VORT MAX TO THE WEST OVER SOUTHERN INDIANA.
DIFFICULT TO TELL AT THIS TIME WHAT THE EXACT SOURCE WILL BE.
PREVIOUS DISCUSSION...
SCATTERED CONVECTION ONGOING ACROSS ENTIRE CWA. APPEARS TO BE JUST
AHEAD OF VORT MAX IN EASTERN KY PER WATER VAPOR IMAGERY. EXPECT
VORT MAX TO MOVE ACROSS LATE THIS AFTERNOON AND EVENING...AND
SHOULD SEE DECREASING CONVECTION AS WE HEAD AFTER SUNSET WITH
LOSS OF HEATING AND VORT MAX MOVING OUT TO THE NORTHEAST.
ELONGATED LINEAR VORT MAX...WELL AHEAD OF THE COLD FRONT...WILL
MOVE INTO FORECAST AREA FROM NW TOMORROW. ENTERING NW CWA 12Z-15Z
AND THEN RUNNING FROM ABOUT HTS-EKN BY END OF NEAR TERM AT 00Z
SUN. TIED LIKELY POPS TO THIS TIME/AREA TREND AS WELL. ALSO
INCLUDED HEAVY RAIN MENTION WITH LIKELY POPS. THINK WE WILL BE ON
THE SOUTHERN FRINGE OF ANY ORGANIZED SEVERE THREAT. BEST CHANCE
FOR ANY ORGANIZED SEVERE WEATHER WOULD BE A COMPLEX THAT FORMS
ALONG THE FRONT TO OUR NW AND THEN ARRIVES INTO OUR SE OHIO
COUNTIES IN THE EVENING WITH DAMAGING WINDS THE MOST LIKELY THREAT.
HOWEVER AS HEIGHTS AND FREEZING LEVELS DROP A BIT...LOCAL
DOWNPOURS...GUSTY WINDS AND SMALL HAIL POSSIBLE IN ANY STRONGER
CELLS.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
MODELS AGREE THE FRONT WILL BE STALLED ACROSS THE CENTRAL OR
NORTHERN PORTIONS OF THE AREA SUNDAY...THEN SLOWLY LIFT BACK NORTH
SUNDAY NIGHT INTO MONDAY...AND FINALLY BE WELL NORTH OF THE AREA BY
MONDAY NIGHT. OUR AREA WILL ALSO BE ON THE SOUTHERN EDGE OF THE
WESTERLIES ALOFT. EMBEDDED SHORT WAVES MOVING OVER THE WARM AND
SOUPY AIRMASS WILL CONTINUE A HIGH THREAT FOR SHOWERS AND
THUNDERSTORMS RIGHT THROUGH TUESDAY. IN THIS PATTERN...TRACKING AND
TIMING OF THESE SHORT WAVES WILL BE DIFFICULT TO EXACTLY DETERMINE
THE CONVECTION SCENARIO. SO...WILL CONCENTRATE CONVECTION SUNDAY AND
SUNDAY NIGHT IN THE CENTRAL AND SOUTH JUST AHEAD OF THE
FRONT...SHIFTING INTO NORTHERN AREAS MONDAY AS THE FRONT LIFTS BACK
NORTH. ON TUESDAY...WILL COAT A HIGH CHANCE EVERYWHERE...EVEN WITH
THE FRONT NORTH OF THE AREA...AS THE MODELS DEPICT A FAIRLY STRONG
AND MORE SYNOPTIC SCALE SHORT WAVE IN THE FLOW. EXCEPT FOR POSSIBLY
THE NORTHERN AREAS SEEING A BRIEF DECREASE IN THE HEAT AND HUMIDITY
SUNDAY...WE LOOK FOR THE WARMTH AND MUGGIES TO DOMINATE RIGHT
THROUGH TUESDAY.
SO THE FLASH FLOOD HAZARD REMAINS WITH US DURING THIS SHORT TERM.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
WITH THE MEAN 500 MB TROF NOT PASSING UNTIL ABOUT THURSDAY...THE
UNSETTLED WEATHER CONTINUES.
NEXT MID LEVEL DISTURBANCE MOVING UP OHIO VALLEY FIGURED FOR AROUND
LATE TUESDAY NIGHT INTO WEDNESDAY....SO HIGHER POPS THEN.
TRIED TO KEEP MAXIMUM TEMPERATURES A BIT LOWER THAN GUIDANCE...WHILE
MINIMUM TEMPERATURES A BIT HIGHER THAN GUIDANCE.
HOPEFULLY SOME DRIER AIR FINALLY REACHING US ABOUT DAY 7.
&&
.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
STARTING WITH VFR CONDITIONS AT ALL SITES WITH SKIES CLEARING FROM
WEST AND NORTH TOWARDS THE CENTRAL MOUNTAINS. AREAS OF IFR/LIFR
FOG EXPECTED TO DEVELOP QUICKLY AT CRW WITH DEWPOINT DEPRESSION OF
2 AND ASSOCIATED RIVER VALLEY FOG AS THE SKIES CLEARS.
ALTO CIRRUS COVERING EKN AND CKB ATTM. EXPECT CIRRUS TO THIN OUT
AND CLEAR FOR POSSIBLE IFR/LIFR DENSE FOG AT EKN AND OTHER
PROTECTED AREAS. CKB COULD STAY MVFR WHERE CONFIDENCE IS LOWER.
BKW SITE SHOULD CONTINUE TO HAVE A BREEZE PREVENTING FOG FORMATION
AS WELL AS OTHER ELEVATED AREAS. NAM MODEL SHOW BOUNDARY LAYER
WIND ABOUT 15 KNOTS WHILE THE RUC13 SHOWS 5 TO 10 KNOTS. SO A
LITTLE CAUTIONS ON FOG CONDITIONS AT ELEVATED SOURCES.
OVERNIGHT TONIGHT...MODELS SHOW A WEAK ENERGY IN THE MID LEVELS
ARRIVING TO SOUTHEAST OH BY 12Z SATURDAY. UNCERTAIN IF CONVECTION
WILL FORM OVERNIGHT ACROSS SOUTHEAST OH. ALTHOUGH WITH THE WEAK
SHORTWAVE PASSING AND A BUBBLE OF RICH THETA-E IN OVER
OH...UNDER SOUTHWEST FLOW IN BOUNDARY LAYER AND WEAK FLOW ALOFT AT
H5.
ANY IFR/LIFR SHOULD QUICKLY LIFT BY 13Z OR EARLIER AT OTHER SITES
THAN CRW...WHICH SHOULD IMPROVE TO MVFR BY 14Z...AND THEN TO VFR
AFTER WARDS. IFR CONDITIONS EXPECTED UNDER AFTERNOON CONVECTION
SATURDAY. SEEMS LIKE A LINE OF THUNDERSTORMS COULD DEVELOP AND
AFFECT MOST SITES AT THE END OF THE PERIODS..
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SUNDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: DENSITY AND TIMING OF FOG MAY VARY TONIGHT.
SYSTEM COULD MATERIALIZE SOUTHEAST OH BY 12Z SATURDAY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE SAT 07/20/13
UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19
EDT 1HRLY 04 05 06 07 08 09 10 11 12 13 14 15
CRW CONSISTENCY L L L L L H H H H H H H
HTS CONSISTENCY L L L L L L H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY L L L L L L H H H H H H
PKB CONSISTENCY L L L L L L H H H H H H
CKB CONSISTENCY M M M M M M H H H H H H
AFTER 06Z SUNDAY...
IFR POSSIBLE IN ANY CONVECTION. IFR ALSO POSSIBLE IN LOW CEILINGS
EACH MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...FB/JMV/MZ
NEAR TERM...MZ/26
SHORT TERM...JMV
LONG TERM...KTB
AVIATION...ARJ/26
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
158 AM EDT SAT JUL 20 2013
.SYNOPSIS...
UPPER HIGH PRESSURE DISSIPATING AS UPPER TROUGH APPROACHES GREAT
LAKES. A COLD FRONT SAGS SLOWLY SOUTHWARD INTO THE AREA THIS
WEEKEND...AND LIFTS BACK NORTH AS A WARM FRONT EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
UPDATED SKIES...POPS...AND WEATHER THROUGH SATURDAY PER LATEST
MODEL RUNS...RADAR...AND SATELLITE IMAGES. REST OF FORECAST
REMAINS REPRESENTATIVE.
PREVIOUS DISCUSSION BELOW...
STRATIFORM RAIN LEFT FROM THE CONVECTION TONIGHT. SHOULD DISSOLVE
OUT OVER THE NEXT COUPLE OF HOURS.
FOCUS THEN TURNS TO THE CONVECTION LATER TONIGHT. LOCAL MODELS
BRING THE RENEWED ACTIVITY LATE TONIGHT INTO THE SOUTHEAST OHIO
COUNTIES BY 12Z. THIS IS AHEAD OF THE LINE OF CONVECTION CURRENTLY
WORKING THROUGH THE SOUTHERN GREAT LAKES AREA...ALTHOUGH IT COULD
ALSO DEVELOP FROM THE VORT MAX TO THE WEST OVER SOUTHERN INDIANA.
DIFFICULT TO TELL AT THIS TIME WHAT THE EXACT SOURCE WILL BE.
PREVIOUS DISCUSSION...
SCATTERED CONVECTION ONGOING ACROSS ENTIRE CWA. APPEARS TO BE JUST
AHEAD OF VORT MAX IN EASTERN KY PER WATER VAPOR IMAGERY. EXPECT
VORT MAX TO MOVE ACROSS LATE THIS AFTERNOON AND EVENING...AND
SHOULD SEE DECREASING CONVECTION AS WE HEAD AFTER SUNSET WITH
LOSS OF HEATING AND VORT MAX MOVING OUT TO THE NORTHEAST.
ELONGATED LINEAR VORT MAX...WELL AHEAD OF THE COLD FRONT...WILL
MOVE INTO FORECAST AREA FROM NW TOMORROW. ENTERING NW CWA 12Z-15Z
AND THEN RUNNING FROM ABOUT HTS-EKN BY END OF NEAR TERM AT 00Z
SUN. TIED LIKELY POPS TO THIS TIME/AREA TREND AS WELL. ALSO
INCLUDED HEAVY RAIN MENTION WITH LIKELY POPS. THINK WE WILL BE ON
THE SOUTHERN FRINGE OF ANY ORGANIZED SEVERE THREAT. BEST CHANCE
FOR ANY ORGANIZED SEVERE WEATHER WOULD BE A COMPLEX THAT FORMS
ALONG THE FRONT TO OUR NW AND THEN ARRIVES INTO OUR SE OHIO
COUNTIES IN THE EVENING WITH DAMAGING WINDS THE MOST LIKELY THREAT.
HOWEVER AS HEIGHTS AND FREEZING LEVELS DROP A BIT...LOCAL
DOWNPOURS...GUSTY WINDS AND SMALL HAIL POSSIBLE IN ANY STRONGER
CELLS.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
BASING FORECAST ON SURFACE FRONT REACHING NEAR A MGW-PKB-UNI LINE BY
12Z SUNDAY...THEN STALLING OUT DURING THE DAY ON SUNDAY...BETWEEN
THAT LINE AND THE HTS-CRW-EKN LINE.
STILL SOME QUESTION HOW QUICKLY THE PRE FRONTAL CONVECTION SAGS
SOUTH INTO NORTHEAST KENTUCKY TO SOUTHERN WEST VIRGINIA SATURDAY
EVENING. TRIED TO SLOW THE SOUTHERN PROGRESS OF THE HIGHER POPS
SOUTHWARD.
PLENTY OF LOW CLOUDS SHOULD LINGER NORTH OF THE FRONT SUNDAY
MORNING. THAT IN COMBINATION WITH THE HIGHER PROBABILITIES OF RAIN
ACROSS THE SOUTHERN HALF OF THE CWA...KEPT MAXIMUM TEMPERATURES
LOWER THAN MOS GUIDANCE.
NEXT MID LEVEL DISTURBANCE MOVES UP THE OHIO VALLEY OVERNIGHT SUNDAY
NIGHT...SO HAVE POPS INCREASING AND MOVING BACK NORTHEAST. THE AXIS
OF THAT MID LEVEL TROF AT 700 TO 500 MB PASSES OVERNIGHT MONDAY
NIGHT.
SO THE FLASH FLOOD HAZARD REMAINS WITH US DURING THIS SHORT TERM.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
WITH THE MEAN 500 MB TROF NOT PASSING UNTIL ABOUT THURSDAY...THE
UNSETTLED WEATHER CONTINUES.
NEXT MID LEVEL DISTURBANCE MOVING UP OHIO VALLEY FIGURED FOR AROUND
LATE TUESDAY NIGHT INTO WEDNESDAY....SO HIGHER POPS THEN.
TRIED TO KEEP MAXIMUM TEMPERATURES A BIT LOWER THAN GUIDANCE...WHILE
MINIMUM TEMPERATURES A BIT HIGHER THAN GUIDANCE.
HOPEFULLY SOME DRIER AIR FINALLY REACHING US ABOUT DAY 7.
&&
.AVIATION /05Z SATURDAY THROUGH WEDNESDAY/...
STARTING WITH VFR CONDITIONS AT ALL SITES WITH SKIES CLEARING FROM
WEST AND NORTH TOWARDS THE CENTRAL MOUNTAINS. AREAS OF IFR/LIFR
FOG EXPECTED TO DEVELOP QUICKLY AT CRW WITH DEWPOINT DEPRESSION OF
2 AND ASSOCIATED RIVER VALLEY FOG AS THE SKIES CLEARS.
ALTO CIRRUS COVERING EKN AND CKB ATTM. EXPECT CIRRUS TO THIN OUT
AND CLEAR FOR POSSIBLE IFR/LIFR DENSE FOG AT EKN AND OTHER
PROTECTED AREAS. CKB COULD STAY MVFR WHERE CONFIDENCE IS LOWER.
BKW SITE SHOULD CONTINUE TO HAVE A BREEZE PREVENTING FOG FORMATION
AS WELL AS OTHER ELEVATED AREAS. NAM MODEL SHOW BOUNDARY LAYER
WIND ABOUT 15 KNOTS WHILE THE RUC13 SHOWS 5 TO 10 KNOTS. SO A
LITTLE CAUTIONS ON FOG CONDITIONS AT ELEVATED SOURCES.
OVERNIGHT TONIGHT...MODELS SHOW A WEAK ENERGY IN THE MID LEVELS
ARRIVING TO SOUTHEAST OH BY 12Z SATURDAY. UNCERTAIN IF CONVECTION
WILL FORM OVERNIGHT ACROSS SOUTHEAST OH. ALTHOUGH WITH THE WEAK
SHORTWAVE PASSING AND A BUBBLE OF RICH THETA-E IN OVER
OH...UNDER SOUTHWEST FLOW IN BOUNDARY LAYER AND WEAK FLOW ALOFT AT
H5.
ANY IFR/LIFR SHOULD QUICKLY LIFT BY 13Z OR EARLIER AT OTHER SITES
THAN CRW...WHICH SHOULD IMPROVE TO MVFR BY 14Z...AND THEN TO VFR
AFTER WARDS. IFR CONDITIONS EXPECTED UNDER AFTERNOON CONVECTION
SATURDAY. SEEMS LIKE A LINE OF THUNDERSTORMS COULD DEVELOP AND
AFFECT MOST SITES AT THE END OF THE PERIODS..
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SUNDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: DENSITY AND TIMING OF FOG MAY VARY TONIGHT.
SYSTEM COULD MATERIALIZE SOUTHEAST OH BY 12Z SATURDAY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE SAT 07/20/13
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EDT 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13
CRW CONSISTENCY M L L L L L L M H H H H
HTS CONSISTENCY L L L L L L L L H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY L L L L L L L L H H H H
PKB CONSISTENCY M L L L L L L L H H H H
CKB CONSISTENCY M M M M M M M M H H H H
AFTER 06Z SUNDAY...
IFR POSSIBLE IN ANY CONVECTION. IFR ALSO POSSIBLE IN LOW CEILINGS
EACH MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...FB/MZ
NEAR TERM...MZ/26
SHORT TERM...KTB
LONG TERM...KTB
AVIATION...ARJ/26
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1137 PM CDT FRI JUL 19 2013
.DISCUSSION...
SEE THE 06Z AVIATION DISCUSSION BELOW.
&&
.AVIATION...
A FEW SHOWERS CONTINUE NEAR THE KJCT TERMINAL AND MAY CONTINUE FOR
A FEW MORE HOURS OVERNIGHT IN AN AREA OF MODEST LARGE SCALE ASCENT
AND WEAK LOW LEVEL WARM ADVECTION. THE DEVELOPMENT OF CLOUDS IN
THE 6-10 KFT LAYER MAY PRECLUDE LOW CLOUDS OVERNIGHT BUT I DID NOT
WANT TO REMOVE THEM JUST YET. WILL LET THE NEXT SHIFT MONITOR THE
TRENDS OVERNIGHT. IF LOW CLOUDS DO FORM...THE ARE EXPECTED TO
RANGE BETWEEN 1-2 KFT AT KJCT/KSOA AND COULD BRIEFLY AFFECT
KSJT/KBBD AFTER SUNRISE AS THE STRATO CU BEGINS TO DEVELOP.
OTHERWISE...EXPECT VFR CONDITIONS WITH A GENERALLY SOUTHERLY WIND
AT 10 KTS OR LESS.
JOHNSON
&&
.PREV DISCUSSION... /ISSUED 938 PM CDT FRI JUL 19 2013/
UPDATE...
ADDED ISOLATED SHOWERS OVER FAR SOUTHERN SECTIONS AND MADE MINOR
TWEAKED TO DEWPOINTS AND SKY COVER FOR THE REST OF TONIGHT.
DISCUSSION...
LATEST NAM AND HRRR ARE INDICATING SOME LIGHT RAIN SHOWERS
DEVELOPING ACROSS PORTIONS OF THE NORTHWEST HILL COUNTRY AND
NORTH EDWARDS PLATEAU AFTER 03Z. THIS SEEMS TO BE TIED TO SOME
ENHANCED LOW LEVEL MOISTURE ADVECTION AND WEAK CONVERGENCE ACROSS
THIS AREA. ADDED ISOLATED RAIN SHOWERS ACROSS SOUTHERN COUNTIES
FOR THE OVERNIGHT PERIOD AND TWEAKED DEWPOINTS AND SKY COVER TO
ACCOUNT FOR TRENDS. UPDATED PRODUCTS HAVE BEEN SENT.
PREV DISCUSSION... /ISSUED 620 PM CDT FRI JUL 19 2013/
DISCUSSION...
SEE THE 00Z AVIATION DISCUSSION BELOW.
AVIATION...
A FEW DIURNAL SHOWERS HAVE DEVELOPED TO THE NORTH OF KABI AND
SOUTHEAST OF KJCT BUT I EXPECT MOST OF THIS TO DISSIPATE WITHIN
THE NEXT 1-2 HOURS AS WE LOSE DAYTIME HEATING. THE CU FIELD WILL
HOLD ON FOR A FEW HOURS BUT SHOULD THIN OVERNIGHT. THERE IS SOME
INDICATION IN THE NAM AND HRRR MODELS THAT NOCTURNAL SHOWERS COULD
DEVELOP SOUTH OF A KSJT TO KBBD LINE TONIGHT BUT CONFIDENCE IS
VERY LOW SO THE TAFS MAINTAIN NO MENTION OF PRECIP. HIGH CLOUDS
WILL CONTINUE TO STREAM FROM THE NORTHWEST TO SOUTHEAST OVERNIGHT
BUT LOW CLOUDS WILL BE THE PRIMARY CONCERN...ESPECIALLY SOUTH OF
KSJT AND KBBD.
PATCHY FOG WILL BE POSSIBLE INTI ALLY TONIGHT...MAINLY AFTER
06Z...WITH STRATUS DEVELOPING AT BOTH KSOA AND KJCT NEAR OR BEFORE
12Z. FARTHER NORTH...WE COULD SEE AN HOUR OR TWO OF MVFR
CONDITIONS AS STRATO CU DEVELOP AFTER SUNRISE...CLOSER TO 14-15Z.
BY 15-16Z...VFR CONDITIONS ARE ANTICIPATED ACROSS WEST CENTRAL
TEXAS WITH AN AFTERNOON CU FIELD AROUND 6 KFT. GENERALLY SOUTH
WINDS ARE EXPECTED TO REMAIN AROUND 10 KTS OR LESS...FOLLOWING OUR
TYPICAL DIURNAL TREND OF VEERING TO THE SOUTHWEST IN THE MORNING
AND BACKING TO THE SOUTHEAST DURING THE LATE AFTERNOON AND EVENING
HOURS.
JOHNSON
PREV DISCUSSION... /ISSUED 340 PM CDT FRI JUL 19 2013/
SHORT TERM...
MUCH QUIETER PATTERN ACROSS WEST CENTRAL TEXAS THIS AFTERNOON...
WEST CENTRAL TEXAS IS BETWEEN SYSTEMS THIS AFTERNOON...WITH THE
UPPER LOW THAT BROUGHT MUCH NEEDED RAINFALL TO THE AREA NOW ACROSS
NORTHWEST MEXICO...AND A SECOND UPPER LOW WORKING ITS WAY INTO
LOUISIANA. SUBSTANTIAL CUMULUS FIELD ACROSS THE AREA THIS
AFTERNOON...BUT THIS CLOUD COVER IS NOT LEADING TO ANY SHOWERS OR
STORMS. VERY LITTLE ENHANCEMENT TO THIS CU FIELD...SO CHANCES OF
ANY DEVELOPMENT ARE SMALL...BUT NOT ZERO...THROUGH SUNSET.
THERE IS CONVECTION ACROSS EAST TEXAS FROM THE LOUISIANA SYSTEM
ACROSS EAST TEXAS THIS AFTERNOON...AND EXPECT IT TO MAKE A RUN
TOWARDS THE HEARTLAND BY SATURDAY AFTERNOON. HOWEVER...LATEST
GLOBAL MODELS AND THE TTU WRF SUGGEST IT WONT QUITE MAKE IT.
WILL KEEP POPS OUT OF THE FORECAST FOR NOW. OTHERWISE...WARM AND
MOIST AIR MASS TO REMAIN IN PLACE. A LITTLE MORE SUN IS ALLOWING
TEMPERATURES TO CLIMB THIS AFTERNOON...AND MORE OF THE SAME FOR
SATURDAY.
LONG TERM...
/SUNDAY THROUGH FRIDAY/
THE MAIN QUESTION IN THE LONG TERM IS WHAT EFFECTS THE RECENT
RAINFALL WILL HAVE ON TEMPERATURES. BUT FIRST...THERE IS A VERY
SLIGHT CHANCE FOR RAIN SUNDAY NIGHT AS A WEAKNESS IN THE RIDGE
DEVELOPS. ALL OF THE MODELS ARE IN FAIRLY GOOD AGREEMENT WITH THE
WEAKNESS DEVELOPING OVER WEST TEXAS AND A LOW DEVELOPING OVER
NORTHERN MEXICO. PREVIOUS MODEL RUNS WERE SUGGESTING THE RAIN
WOULD BE ON MONDAY. LOOKING AT THE GFS ENSEMBLES 12 HOUR RAIN
PROBABILITIES...IT HAS SLIGHTLY BETTER CHANCES SUNDAY NIGHT AND
BACKS OFF FOR MONDAY. THE ECMWF DETERMINISTIC MODEL IS SLIGHTLY
WETTER THAN THE GFS. GIVEN THE LACK OF MUCH SUPPORT AT THE SURFACE
TO INITIATE ANYTHING...I AM GOING WITH MORE OF THE GFS...NAM
SOLUTION AND HAVE SOME SLIGHT CHANCES ACROSS THE NORTHERN EDWARDS
PLATEAU AND NORTHWEST HILL COUNTRY SUNDAY NIGHT.
OTHERWISE...THE RIDGE BUILDS BACK IN AND TEMPERATURES WARM THROUGH
THE END OF NEXT WEEK AS WE BEGIN TO DRY OUT. THE AIR SHOULD STAY
FAIRLY MOIST AS IT WILL TAKE A WHILE FOR THE THE SOIL MOISTURE TO
RETURN TO A MORE NORMAL LEVEL FOLLOWING THE RAIN THIS WEEK. WINDS
WILL STAY OUT OF THE SOUTH TO SOUTHEAST...SO I WOULD NOT EXPECT TO
SEE RAPID DRYING. SOME OF THE MODEL GUIDANCE IS TRYING TO TAKE
TEMPERATURES JUST OVER 100 DEGREES...BUT THIS IS OVER THE AREA
THAT HAS RECEIVED THE HIGHER RAIN AMOUNTS. GIVEN THAT THE HIGHER
SOIL MOISTURE SHOULD HELP TO KEEP TEMPERATURES JUST A BIT
COOLER...I HAVE TENDED TEMPERATURES TOWARDS THE RAW GFS SOLUTION
WITH TEMPERATURES IN THE MID TO UPPER 90S.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 71 94 72 94 72 / 10 10 5 5 10
SAN ANGELO 69 93 71 94 71 / 10 10 5 10 10
JUNCTION 69 93 70 93 71 / 10 10 10 10 20
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
25
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
317 AM CDT SAT JUL 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 317 AM CDT SAT JUL 20 2013
CURRENTLY AS OF 08Z...
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED NORTHWEST FLOW
FROM SOUTHWEST CANADA INTO THE GREAT LAKES REGION WITH TROUGHING
CENTERED OVER SOUTHEAST CANADA. NUMEROUS SHORTWAVES WERE PRESENT
WITHIN THE NORTHWEST FLOW...MOST WEAK BUT A FEW WORTH KEYING IN ON.
THE FIRST WAS OVER CENTRAL WISCONSIN WHICH MANAGED TO CARRY SHOWERS
ALMOST INTO TAYLOR AND CLARK COUNTIES BEFORE THEY DISSIPATED. MID
CLOUDS WERE CROSSING TAYLOR/CLARK...THOUGH. A SECOND SHORTWAVE WAS
OVER CENTRAL MN PRODUCING SOME SHOWER ACTIVITY. THIS SHOWER ACTIVITY
TOO WAS DISSIPATING BEING AT THE DAYTIME MINIMUM IN INSTABILITY. THE
THIRD SHORTWAVE OF NOTE...CONVECTIVELY INDUCED AND STILL MAINTAINING
SOME SHOWERS AND THUNDERSTORMS...WAS BACK OVER CENTRAL SOUTH DAKOTA.
DEEP LAYER MOISTURE HAS DEFINITELY DRIED OUT WITH PRECIPITABLE WATER
VALUES FROM 00Z SOUNDINGS RANGING BETWEEN 0.75 AND 1 INCH FROM THE
DAKOTAS INTO THE FORECAST AREA. THIS DRIER AIR HAS KEPT THE FORECAST
AREA OUTSIDE OF THAT CENTRAL WI DRY AND MOSTLY CLEAR OVERNIGHT.
TEMPERATURES WERE MUCH COOLER THIS MORNING THANKS TO THE PASSAGE OF
THE COLD FRONT YESTERDAY...WITH READINGS MAINLY IN THE 60S. 925MB
TEMPS HAVE ALSO COOLED...DOWN TO 22C AT MPX AT 00Z.
SYNOPTIC OVERVIEW...
A NORTHWEST FLOW STAYS IN PLACE ALOFT THROUGH THE SHORT TERM PERIOD.
MUCH OF THE FOCUS IS ON CONVECTIVELY INDUCED SHORTWAVES DEVELOPING
AND RIDING THROUGH THE NORTHWEST FLOW.
TODAY...
ATTENTION IS ON THE SHORTWAVE AND CONVECTION ACROSS CENTRAL SOUTH
DAKOTA. THE 20.00Z NAM REMAINS FAIRLY CONSISTENT IN BRINGING THIS
SHORTWAVE INTO WESTERN PORTIONS OF THE FORECAST AREA THIS AFTERNOON.
CONVECTION CURRENTLY WITH IT MAY EITHER HOLD TOGETHER OR DEVELOP AS
MLCAPE VALUES CLIMB INTO THE 500-1500 J/KG RANGE WITH LITTLE IN THE
WAY OF CIN. ANOTHER POSSIBLE TRIGGER FOR CONVECTION LOOKS TO BE A
LOW PRESSURE TROUGH OVER NORTHERN WI WHICH MODELS DROP DOWN JUST
SOUTH OF I-90 BY 21Z. 0-2KM CONVERGENCE IS VERY WEAK ON THIS
TROUGH...THOUGH. 20.00Z GFS/ECMWF AGREE WITH THE NAM ON THE
POTENTIAL FOR CONVECTIVE ACTIVITY WITH HIGH RESOLUTION MODELS
TENDING TO SUGGEST ISOLATED/SCATTERED CONVECTION. FOLLOWED THE HIGH
RESOLUTION MODELS WITH 20-40 PERCENT CHANCES...HIGHEST WEST OF THE
MS RIVER. IT SHOULD BE NOTED THAT 0-6KM SHEAR IS 40-45 KT...SO IF A
VIGOROUS ENOUGH UPDRAFT CAN FORM...WE COULD SEE A SEVERE STORM.
925MB TEMPS TODAY FROM 20C NORTH TO 23C SOUTH COMBINED WITH SUN
THROUGH ABOUT MID AFTERNOON SUPPORT HIGHS FROM THE MID 70S TO MID
80S.
TONIGHT...
CONVECTION THAT IS AROUND LATE THIS AFTERNOON LOOKS LIKE IT COULD
DIMINISH DURING THE EVENING WITH LOSS OF HEATING. FOCUS THEN TURNS
BACK TO THE WEST WHERE ALL MODELS HAVE BEEN CONSISTENT IN DEVELOPING
A CONVECTIVE SYSTEM AND SHORTWAVE OVER CENTRAL SOUTH DAKOTA INTO
NEBRASKA DURING THE EVENING. AS THIS SHORTWAVE TRACKS SOUTHEAST INTO
IOWA AND KANSAS DURING THE OVERNIGHT HOURS...ALONG WITH THE NORMAL
NOCTURNAL INCREASE IN THE LOW LEVEL JET...850MB MOISTURE TRANSPORT
INCREASES DOWNSTREAM. IT APPEARS THE BIGGER FOCUS FOR PRECIPITATION
WILL END UP BEING ALONG I-70...AROUND THE SAME SPOT WHERE THE COLD
FRONT THAT WENT THROUGH THE AREA YESTERDAY ENDS UP STALLING OUT AT.
HOWEVER...THE 20.00Z NAM/GFS/ECMWF SUGGEST THERE STILL MAY BE ENOUGH
850MB MOISTURE TRANSPORT FORCING FARTHER NORTH TO PRODUCE SOME
SHOWER/STORM ACTIVITY OVER THE FORECAST AREA. ON THE OTHER
HAND...THE 20.00Z REGIONAL CANADIAN KEEPS ANY OF THIS 850MB MOISTURE
TRANSPORT ACTIVITY WELL WEST OF THE AREA BEFORE 12Z SUNDAY. SINCE
THIS REGIONAL CANADIAN SCENARIO IS DEFINITELY PLAUSIBLE...AND HAVING
THE CONCERN FOR CONVECTION TO THE SOUTH...HAVE KEPT CHANCES OF
PRECIPITATION IN THE 20-40 RANGE OVERNIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 317 AM CDT SAT JUL 20 2013
SYNOPTIC OVERVIEW...
20.00Z ECMWF/GFS/CANADIAN CONTINUE TO ADVERTISE THE NORTHWEST FLOW
PATTERN REMAINING IN PLACE THROUGH WEDNESDAY. HEADING INTO THURSDAY
AND FRIDAY...RIDGING STUCK OVER THE WESTERN U.S. MAY TRY TO SHIFT
EAST...BUT AT THE SAME TIME A VIGOROUS TROUGH IS PROGGED TO DROP
INTO NORTHERN ONTARIO AND LAKE SUPERIOR...EFFECTIVELY PREVENTING THE
RIDGE FROM BUILDING UP INTO THE FORECAST AREA.
SUNDAY INTO MONDAY NIGHT...
THE SHORTWAVE TROUGH OVER IOWA AND KS AT 12Z SUNDAY IS PROGGED TO
TRACK EAST THROUGH SOUTHERN SECTIONS OF THE FORECAST AREA LATE
SUNDAY. HARD TO SAY HOW MUCH ACTIVITY THERE MAY BE IN THE MORNING.
HOWEVER...INCREASING DAYTIME INSTABILITY COUPLED WITH THE APPROACH
OF THE SHORTWAVE AND A SURGE OF WARM ADVECTION SHOULD BE ENOUGH TO
PRODUCE SHOWERS AND STORMS OVER MUCH OF THE FORECAST AREA FOR THE
AFTERNOON. 20.00Z GFS/NAM/ECMWF/REGIONAL CANADIAN ALL HAVE PRECIP
FOR THE AFTERNOON...THUS THE 60 PERCENT CHANCES FROM THE PREVIOUS
FORECAST SEEMS REASONABLE. IF MODELS REMAIN CONSISTENT...THESE MAY
NEED TO BE RAISED FURTHER. AS THE SHORTWAVE TROUGH PUSHES EAST
SUNDAY NIGHT AND DIURNAL COOLING HAS ITS INFLUENCE ON THE
CONVECTION...EXPECT THE CONVECTION TO SLIDE EAST AND WEAKEN. DID
LOWER PRECIPITATION CHANCES AFTER MIDNIGHT INTO MONDAY MORNING.
20.00Z ECMWF EVEN SUGGESTS ALL OF SUNDAY NIGHT COULD END UP DRY.
ATTENTION THEN TURNS TO A VIGOROUS SHORTWAVE TROUGH CROSSING FROM
SOUTHERN MANITOBA INTO NORTHERN ONTARIO ON MONDAY. THE ASSOCIATED
COLD FRONT WITH THIS FEATURE LOOKS TO CROSS THE FORECAST AREA LATE
IN THE DAY INTO THE EVENING HOURS. THIS IS VERY GOOD TIMING BECAUSE
IT IS RIGHT AFTER PEAK HEATING. MONDAY SHOULD BE WARM AND HUMID AS
WELL AS SOUTHERLY WINDS AHEAD OF THE FRONT INCREASE TEMPS/DEWPOINTS.
925MB TEMPS CLIMBING TO 22-24C AT 18Z PER 20.00Z ECMWF EASILY BRINGS
HIGHS INTO THE 80S. WOULD NOT BE SURPRISED TO SEE A 90F. THERE ARE
THREE BIG QUESTION MARKS WITH THE FRONT...THOUGH:
1. HOW MUCH FORCING ALOFT WILL THERE BE. MOST MODELS DEPICT ALL THE
MID TO UPPER LEVEL FORCING STAYING TO THE NORTH OF THE AREA.
2. POTENTIAL FOR CAPPING AS A SURGE OF WARMER 800MB AIR FLOWS OUT OF
THE DAKOTAS AND INTO THE FORECAST AREA OVER THE FRONT.
3. 0-2 KM CONVERGENCE ON THE FRONT IS PROGGED TO BE WEAK AT
BEST...PARTIALLY DUE TO THE MID/UPPER FORCING WELL OFF TO THE NORTH.
GIVEN GOOD MODEL SIGNAL FOR PRECIPITATION...HAVE CHANCES IN THE
40-50 RANGE DURING THE FRONTAL PASSAGE. HOWEVER...GIVEN THE
QUESTIONS ABOVE...THE FRONT COULD COME THROUGH DRY OR MAYBE JUST
HAVE ISOLATED STORMS ALONG IT. SHOULD CONVECTION OCCUR...0-3KM SHEAR
VALUES APPROACH 30 KT WHICH COULD SUPPORT ISOLATED DAMAGING WINDS.
CONFIDENCE IS NOT PARTICULARLY HIGH FOR SEVERE...THOUGH.
TUESDAY THROUGH FRIDAY NIGHT...
DESPITE THE NORTHWEST FLOW ALOFT FOR TUESDAY THROUGH THURSDAY...
WHICH LOOKS TO CARRY A VARIETY OF WEAK SHORTWAVES THROUGH THE
FORECAST AREA WITH IT...20.00Z ECMWF/GFS/CANADIAN ARE IN PRETTY GOOD
AGREEMENT ON KEEPING THE FORECAST AREA DRY. THIS IS ALL BECAUSE OF
CANADIAN HIGH PRESSURE BUILDING IN BEHIND THE FRONTAL PASSAGE MONDAY
NIGHT. DRY AIR ASSOCIATED WITH THE HIGH EFFECTIVELY KEEPS THE AREA
DRY. MAY HAVE TO KEEP AN EYE ON THURSDAY FOR POSSIBLE INTRODUCTION
OF PRECIPITATION CHANCES SINCE THE HIGH PRESSURE AREA IS PROGGED TO
SHIFT OFF TO THE EAST. GIVEN THE CANADIAN NATURE OF THE
HIGH...EXPECT COOLER TEMPERATURES...ESPECIALLY COMPARED TO MONDAY.
850MB TEMPS GENERALLY HOVER BETWEEN 10-13C...SUPPORTING HIGHS IN THE
MID 70S TO NEAR 80. THE ECMWF REMAINS VERY CONSISTENT IN SHOWING A
STRONGER SHORTWAVE TRACKING OUT OF NEBRASKA THURSDAY NIGHT AND
HEADING SOUTHEAST INTO IL AND MO FRIDAY NIGHT. THE 20.00Z GFS IS
VERY SIMILAR. IF THESE MODEL SOLUTIONS END UP VERIFYING...AT A
MINIMUM THE SOUTHERN HALF OF THE FORECAST AREA LOOKS FAVORABLE TO
SEE SOME SHOWERS AND STORMS...ESPECIALLY ON FRIDAY. FOLLOWED THE
MODEL CONSENSUS FOR PRECIPITATION CHANCES...IN THE 30-40 RANGE.
ADDITIONALLY...IN THE WAKE OF THIS SHORTWAVE...ANOTHER CANADIAN HIGH
PRESSURE AREA IS AIMED TO DROP SOUTH TOWARDS THE FORECAST AREA FOR
NEXT WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1050 PM CDT FRI JUL 19 2013
SOME UPPER LEVEL FORCING...COUPLED WITH A BIT OF LOW LEVEL MOISTURE
CONVERGENCE/INSTABILTY...WAS SPARKING A SMALL AREA OF SHRA/TS OVER
CENTRAL MN. IT LOOKS LIKE THIS WILL HOLD TOGETHER FOR THE OVERNIGHT
HOURS...WORKING INTO WESTERN WI. BELIEVE THE PCPN WILL STAY NORTH OF
THE TAF SITES AT THIS MOMENT...SO WILL LEAVE ANY MENTION OUT OF THE
FORECAST.
GENERALLY VFR THOUGH THE DAY...BUT CLOUDS WILL BE ON THE INCREASE
FROM THE WEST THANKS TO ANOTHER UPPER LEVEL FEATURE. SOME SHRA/TS
ARE ALSO POSSIBLE...WHICH COULD IMPACT KRST. COVERAGE COULD BE MORE
SCATTERED THOUGH...AND CONFIDENCE ISN/T HIGH ENOUGH TO ADD SHRA OR
VCSH YET. SOMETHING TO MONITOR. CLOUDS WILL CONTINUE TO INCREASE AND
THICKEN FROM THE WEST SAT NIGHT...BUT LOOKS TO STAY VFR. RAIN
CHANCES WILL INCREASE FOR SUN/MON THANKS TO A FEW DIFFERENT WEATHER
TRIGGERS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
252 AM MDT SAT JUL 20 2013
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 230 AM MDT SAT JUL 20 2013
FORECAST CHALLENGES DEAL WITH THUNDERSTORM CHANCES AND SEVERE
POSSIBILITIES THIS AFTERNOON.
CURRENTLY...PRETTY TRANQUIL WEATHER CONDITIONS ACROSS THE CWFA
THIS MORNING SO FAR. HAVE A FRONTAL BOUNDARY ANALYZED FROM KGCC TO
KRWL THIS MORNING ON SURFACE ANALYSIS. SURFACE LOW NEAR RIVERTON.
HAVE ANOTHER COLD FRONT PUSHING SOUTH NEAR BISMARK...EXTENDING
NORTHWEST INTO EASTERN MONTANA. LATEST FORECAST SOUNDINGS SHOWING
A CAPPING INVERSION IN THE LOWER LAYERS NEAR 700MBS. SEEING SOME
LIGHTNING STRIKES OUT NEAR RIVERTON...BUT SO FAR FOR THE CHEYENNE
CWFA...SKIES ARE PRETTY MUCH CLEAR.
SHOULD BEGIN TO SEE AN INCREASE IN SHOWERS AND THUNDERSTORMS LATER
ON TODAY AS THE NORTH DAKOTA COLD FRONT MOVES SOUTH INTO WESTERN
NEBRASKA THIS AFTERNOON. NORTHEAST UPSLOPING WINDS SHOULD HELP US
HERE EAST OF THE LARAMIE RANGE. 700MB CAPPING INVERSION ERODES BY
21Z OR SO WITH CAPES AROUND 1200 J/KG HERE AT CHEYENNE WITH NO
CONVECTIVE INHIBITION. LIFTED INDICES OUT IN THE PANHANDLE DOWN TO
-5C THIS AFTERNOON. CAPES UP TO 2000 J/KG OUT IN THE PANHANDLE. WENT
AHEAD AND INCREASED POPS A LITTLE EAST OF THE LARAMIE RANGE AND IN
THE PANHANDLE FOR THIS AFTERNOON AND ADDED SEVERE THUNDERSTORM
WORDING IN THE FORECAST FOR THE PANHANDLE. A SLIGHT RISK AREA HAS
BEEN ISSUED FOR THE PANHANDLE BY THE STORM PREDICTION CENTER. DAY
SHIFT MAY NEED TO UPDATE THE FORECAST FOR AREAS IN SOUTHEAST
WYOMING EAST OF THE LARAMIE RANGE BASED ON RADAR TRENDS LATER
TODAY. LATEST HRRR COMPOSITE REFLECTIVITY HAS THUNDERSTORMS
FORMING OVER THE LARAMIE RANGE AROUND 18Z...DRIFTING EASTWARD
TOWARDS THE PANHANDLE DURING THE AFTERNOON HOURS. STORMS ARE GOING
TO BE SLOW MOVING WITH STORM MOTION FORECASTS FROM THE NORTHWEST
UNDER 10KTS...SO THOSE FORTUNATE ENOUGH TO BE UNDER ONE OF THESE
STORMS SHOULD SEE QUITE A BIT OF RAINFALL. NAM PRECIPITABLE WATER
FORECASTS AROUND .9 INCHES HERE AT CHEYENNE AND 1.1 INCHES OUT
IN THE PANHANDLE. WITH RECENT RAINS OUT IN THE PANHANDLE...A FLASH
FLOOD THREAT COULD EXIST AS WELL. DAY SHIFT WILL NEED TO WATCH
THIS CLOSELY.
FRONTAL BOUNDARY SHIFTS EAST INTO CENTRAL NEBRASKA THIS EVENING
WITH SHOWERS AND THUNDERSTORMS COMING TO AN END TOWARDS MIDNIGHT.
SUNDAY LOOKS MAINLY DRY WEST OF THE LARAMIE RANGE AS AN UPPER
LEVEL RIDGE BUILDS INTO THE AREA. BEST CHANCES FOR SHOWERS AND
THUNDERSTORMS CONTINUES TO BE THE PANHANDLE AS THEY STAY IN THE
SOUTHEAST LOW LEVEL WIND FLOW THROUGH THE AFTERNOON. GFS AND ECMWF
SIMILAR ON QPF PLACEMENT FOR SUNDAY...SO KEPT CHANCE POPS GOING
EAST OF THE LARAMIE RANGE.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 111 AM MDT SAT JUL 20 2013
MEDIUM RANGE MODELS SHOW DRIER AIR PUSHING ACROSS SOUTHEAST
WYOMING AND INTO PORTIONS OF WESTERN NEBRASKA ON TUESDAY. UPPER
LEVEL HIGH PRESSURE WHICH HAS ESTABLISHED ITSELF ACROSS THE
WESTERN THIRD OF THE UNITED STATES MOST OF THIS SUMMER...WILL
DRIFT EAST OVER THE CENTRAL ROCKIES AND BUILD NORTHWARD. MIDLEVEL
SUBSIDENCE AND DRY NORTHWEST FLOW ALOFT WILL REDUCE CONVECTIVE
DEVELOPMENT ON TUESDAY...ALTHOUGH IT WILL BE RATHER MOIST NEAR THE
SURFACE ACROSS WESTERN NEBRASKA WHERE DEWPOINTS WILL REMAIN IN THE
50 TO 60 DEGREE RANGE WITH UPSLOPE EASTERLY WINDS. HIGH
TEMPERATURES IN THE 90S ARE EXPECTED ACROSS MOST OF THE FORECAST
AREA ON TUESDAY.
FOR THE MIDDLE OF THE WEEK...MODELS SHOW THE UPPER LEVEL FLOW
TRANSITIONING TO A MORE ZONAL PATTERN AS A FEW UPPER LEVEL
SHORTWAVES PUSH ACROSS THE NORTHERN AND CENTRAL ROCKIES. EXPECT
SLIGHTLY COOLER TEMPERATURES EACH DAY AND A HIGHER CHANCE OF
SHOWERS AND THUNDERSTORMS RETURNING TO THE REGION. WEDNESDAY
AFTERNOON IS TRICKY IN TERMS OF TSTORM CHANCES...WITH MODEL
SOUNDINGS SHOWING A CAPPED ENVIRONMENT WITH A WARM LAYER JUST
ABOVE 700MB. SOUNDINGS SHOW PW/S OVER 1 INCH AND CAPE OF 2500 J/KG
WITH BREEZY SOUTHEAST WINDS. NOT COMFORTABLE WITH POP BELOW 15
PERCENT NEAR THE MOUNTAINS...SO INCREASED POP AND ADDED A SLIGHT
CHANCE OF TSTORMS TO THE HIGH PLAINS ADJACENT OF THE LARAMIE
RANGE. CIN VALUES ARE BETWEEN -20 TO -50 J/KG IN THESE LOCATIONS
WHICH IS NOT QUITE ENOUGH TO PREVENT ISOLATED CONVECTION. ACROSS
THE PANHANDLE...CIN VALUES ARE OVER -200 J/KG WHICH SHOULD KEEP
THOSE AREAS DRY...AT LEAST INTO WEDNESDAY NIGHT. SCATTERED SHOWERS
AND TSTORMS WILL LIKELY RETURN TO ALL OF SOUTHEAST WYOMING AND
WESTERN NEBRASKA ON THURSDAY AS A VIGOROUS SHORT WAVE PUSHES
ACROSS THE AREA. FRIDAY WILL CONTINUE THIS TREND WITH COOLER
TEMPERATURES LOWERING INTO THE UPPER 70S TO LOW 80S FOR HIGHS WITH
WIDELY SCATTERED/SCATTERED TSTORMS POSSIBLE IN THE AFTERNOON AND
EVENING HOURS. WITH SUBTROPICAL MOISTURE FLOWING NORTHWARD...WILL
HAVE TO KEEP AN EYE ON FLASH FLOODING BY LATE NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1150 PM MDT FRI JUL 19 2013
VFR CONDITIONS WILL PREVAIL TONIGHT THROUGH 18Z SATURDAY. SURFACE
WINDS WILL BE VARIABLE 10 KT OR LESS WITH CLEAR SKIES. THERE IS A
BETTER CHANCE OF THUNDERSTORMS FOR TERMINALS ACROSS THE HIGH PLAINS
INTO WESTERN NEBRASKA SATURDAY AFTERNOON. ADDED VCTS TO THE FORECAST
FOR NOW SINCE TIMING OF THESE THUNDERSTORMS IS RATHER UNCERTAIN
TONIGHT.
&&
.FIRE WEATHER...
ISSUED AT 230 AM MDT SAT JUL 20 2013
ANOTHER CHANCE FOR WETTING RAINS MAINLY IN THE PANHANDLE AND EAST
OF THE LARAMIE RANGE THIS AFTERNOON. EASTERLY WINDS WILL BE LIGHT
TODAY AND ARE EXPECTED TO REMAIN LIGHT FROM THE EAST THROUGH
SUNDAY. DRIER CONDITIONS RETURN SUNDAY INTO NEXT WEEK AS HIGH
PRESSURE BUILDS INTO COLORADO. WE COULD BE LOOKING AT ELEVATED TO
CRITICAL FIRE WEATHER CONDITIONS TUESDAY AS WINDS INCREASE INTO
THE 25 TO 35 MPH RANGE. THIS IS DUE TO A LOW PRESSURE SYSTEM
MOVING THROUGH NORTHERN WYOMING AND MONTANA TUESDAY AFTERNOON.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...CLAYCOMB
LONG TERM...TJT
AVIATION...TJT
FIRE WEATHER...CLAYCOMB
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
840 AM MST SAT JUL 20 2013
.SYNOPSIS...
A VERY MOIST AIRMASS IS EXPECTED TO REMAIN OVER THE REGION AS A LOW
PRESSURE SYSTEM IN MEXICO MOVES OFF WELL TO SOUTH AND WEST. ABOVE
NORMAL RAIN CHANCES AND BELOW NORMAL TEMPERATURES ARE EXPECTED
THROUGH MONDAY. SOMEWHAT DRIER AND WARMER WEATHER IS EXPECTED FROM
TUESDAY ONWARD THROUGH THE END OF NEXT WEEK AS HIGH PRESSURE BECOMES
REESTABLISHED ACROSS THE ROCKIES.
&&
.DISCUSSION...
AFTER A RATHER ACTIVE NIGHT...WITH WIDESPREAD RAINFALL BEING
REPORTED FROM AN MCS THAT MOVED FROM THE NORTHERN AND WESTERN
PORTION OF THE PHOENIX AREA ACROSS SOUTHWEST ARIZONA...AND INTO THE
LOWER COLORADO RIVER VALLEY...THINGS HAVE QUIETED DOWN CONSIDERABLY
ACROSS THE REGION THIS MORNING. THE MCS THAT BROUGHT ALL THE
RAINFALL EARLIER THIS MORNING HAS WEAKENED TO JUST A FEW SHOWERS
ACROSS WESTERN AZ AND THE LOWER COLORADO RIVER VALLEY. THE MAIN
IMPACT FROM THE RAINFALL AND CLOUDINESS IS TO COOL TEMPERATURES
ACROSS MUCH OF THE REGION...WITH MANY LOCATIONS ACROSS THE LOWER
DESERTS OF WESTERN AZ AND THE LOWER COLORADO RIVER VALLEY NOW SEEING
TEMPERATURES IN THE 70S. THIS RAIN-COOLED AIR AND DEBRIS CLOUDS WILL
LIKE DELAY THE ONSET OF CONVECTIVE ACTIVITY TODAY...WITH THE LATEST
MODEL RUNS SHOWING SHOWER AND THUNDERSTORM DEVELOPMENT HOLDING OFF
UNTIL THIS EVENING AND TONIGHT. OTHER THAN SOME ADJUSTMENTS TO LOWER
TEMPERATURES ACROSS SOUTHWEST AZ AND SOUTHEAST CA...CURRENT GRIDDED
FORECAST ARE HOLING UP QUITE WELL.
&&
.PREVIOUS DISCUSSION...
UPPER LOW CONTINUES TO SPIN ACROSS THE CENTRAL GULF OF CALIFORNIA
THIS MORNING. EXTENDING NORTHWARD FROM THE LOW INTO CENTRAL AZ IS AN
INVERTED TROUGH AND MCV...WHICH HAVE HELPED TO SUSTAIN A NOCTURNAL
MCS ACROSS THE LOWER DESERTS OF AZ. LATEST IR IMAGERY INDICATES THAT
CLOUD TOPS HAVE COOLED TO AS LOW AS -75C...WHICH CORRELATES TO TOPS
AROUND 40-45K FT...THOUGH KIWA RADAR SUGGESTS SOME OVERSHOOTING TOPS
MAY BE AS HIGH AS 55K FT. MUCH OF PHOENIX...NORTH SCOTTSDALE AND THE
WEST VALLEY RECEIVED MEASURABLE RAINFALL OVER THE PAST 6
HOURS...WITH SOME SPOTS MEASURING ALMOST AN INCH. WIDESPREAD SHOWER
AND THUNDERSTORM ACTIVITY CONTINUES AT THIS HOUR FROM MARICOPA
COUNTY WESTWARD...INCLUDING LA PAZ...YUMA AND RIVERSIDE COUNTIES. IT
IS EXPECTED THAT CONVECTION WILL CONTINUE TO DEVELOP EARLY THIS
MORNING ALONG OUTFLOW BOUNDARIES PROPAGATING INTO THE MOISTURE-RICH
ENVIRONMENT OF SW AZ AND SE CA. HEAVY RAINFALL AND MINOR FLOODING
ARE THE MAIN THREATS WITH THESE STORMS.
GLOBAL MODELS NOTORIOUSLY HAVE A DIFFICULT TIME INITIALIZING
PROPERLY WHEN THERE IS CONVECTION OVERNIGHT. FORECAST IS INSTEAD
WEIGHTED MORE TOWARDS THE HI-RES CONVECTIVE ALLOWING MODELS SUCH AS
THE WRF-NMM FOR SPC...WHICH HAS PICKED UP ON THE CURRENT ACTIVITY.
ALTHOUGH THE EASTERLY FLOW BETWEEN THE LOW TO THE SOUTH AND THE
ANTICYCLONE ACROSS NV WILL DIMINISH TODAY...SOUTH-CENTRAL AZ IS
AGAIN FAVORED FOR NOCTURNAL CONVECTION. CONDITIONS REMAIN SO
ANOMALOUSLY MOIST THAT MODELS SUCH AS THE HRRR SUGGEST THAT
CONVECTION MAY INITIATE AS EARLY AS THIS AFTERNOON. TEMPERATURES
WILL ALSO BE CONSIDERABLY LOWER TODAY...WITH HIGH TEMPERATURES
STRUGGLING TO REACH THE 100 DEGREE MARK IN THE LOWER DESERTS.
THE UPPER LOW ACROSS THE GOC IS EXPECTED TO LIFT NORTHWARD TO A
POSITION JUST WEST OF ROCKY POINT SUNDAY. THE THREAT OF SHOWERS AND
THUNDERSTORMS WILL PERSIST JUST ABOUT EVERYWHERE ACROSS THE FORECAST
AREA. POPS IN THE 12Z-18Z PERIOD SUNDAY WERE INCREASED...OWING TO
MUCH HIGHER PROBABILITIES FROM THE NMM-BASED GUIDANCE SUCH AS THE
SREF. WITH THE AMPLE MOISTURE AND SUBSEQUENT CLOUDINESS...AN
ADDITIONAL 3 TO 5 DEGREES OF COOLING IS ALSO ANTICIPATED.
EARLY NEXT WEEK...THE UPPER LOW WILL GET PICKED UP BY THE WESTERLIES
AS THE ANTICYCLONE SLIDES TOWARDS THE FOUR CORNERS. THE RESULTING
SOUTHWESTERLY FLOW WILL ADVECT DRIER AIR INITIALLY INTO SE CA AND SW
AZ...WHICH WILL CONFINE THE HIGHEST POPS TO HIGHER TERRAIN NORTH AND
EAST OF PHOENIX. THE RIDGE WILL BECOME REESTABLISHED ACROSS THE
SOUTHERN PLAINS THURSDAY...WHICH WILL ALLOW ANOTHER MOIST INVERTED
TROUGH TO APPROACH SOUTHERN AZ. CONSEQUENTLY...A RETURN TO NEAR
CLIMO POPS/TEMPS IS FORECAST FOR THE END OF THE WEEK.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL...
NEW STORMS CONTINUE TO DEVELOP OVER HIGHER TERRAIN EAST OF GLOBE.
ALTHOUGH SLOW TO MOVE WEST...MAY SEE EASTERLY OUTFLOW FROM THESE
STORMS AFFECTING KIWA LATER AFTER 11Z. OUTSIDE OF THIS ACTIVITY...
LIGHT WINDS AND SCT-BKN CLOUD DECKS GENERALLY AOA 10KFT ARE EXPECTED
ACROSS THE SOUTH-CENTRAL AZ DESERTS THIS MORNING. BY 20Z...STORMS
WILL AGAIN FORM OVER THE HIGHER TERRAIN NORTH AND EAST OF PHOENIX.
SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH...
SHOWER/THUNDERSTORM ACTIVITY WILL CONTINUE TO FILL IN OVER SOUTHEAST
CALIFORNIA THIS MORNING THROUGH AT LEAST 13Z...WITH GUSTY OUTFLOWS
UP TO 30KT POSSIBLE AT TIMES. SCT-BKN CLOUD DECKS GENERALLY AOA
10KFT WITH LOCAL CIGS DOWN TO 8KFT IN HEAVIER SHOWERS AND
THUNDERSTORMS...SKIES IMPROVING LATER THIS MORNING. WINDS SOUTHERLY
10-15KT THROUGH MUCH OF THE TAF PERIOD ACROSS THE LOWER COLORADO
RIVER VALLEY WITH LIGHTER SOUTHEASTERLY WINDS AT KIPL.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
ABOVE NORMAL PRECIP CHANCES WILL REMAIN A POSSIBILITY ON MONDAY AS A
AN AREA OF LOW PRESSURE EXISTS THE AREA. A SWITCH TO A SOUTHERLY
FLOW ALOFT WILL LIKELY BRING DRYING CONDITIONS AND ENDING
PRECIPITATION CHANCES ACROSS SOUTHEAST CALIFORNIA AND SOUTHWEST
ARIZONA FOR THE MIDDLE OF NEXT WEEK. HUMIDITIES WILL REMAIN ELEVATED
THROUGH THE ENTIRE PERIOD WITH AFTERNOON HUMIDITIES ONLY DROPPING
INTO THE 20-30 PERCENT RANGE WITH GOOD OVERNIGHT RECOVERY. STORM
COVERAGE AND INTENSITY WILL VARY FROM DAY TO DAY WHICH WILL IMPACT
FORECAST WINDS...POTENTIALLY DISRUPTING NORMAL DIURNAL PATTERNS.
$$
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...PERCHA/HIRSCH
AVIATION...MEYERS
FIRE WEATHER...KUHLMAN
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
330 AM MST SAT JUL 20 2013
.SYNOPSIS...
A VERY MOIST AIRMASS IS EXPECTED TO REMAIN OVER THE REGION AS A LOW
PRESSURE SYSTEM IN MEXICO MOVES OFF WELL TO SOUTH AND WEST. ABOVE
NORMAL RAIN CHANCES AND BELOW NORMAL TEMPERATURES ARE EXPECTED
THROUGH MONDAY. SOMEWHAT DRIER AND WARMER WEATHER IS EXPECTED FROM
TUESDAY ONWARD THROUGH THE END OF NEXT WEEK AS HIGH PRESSURE BECOMES
REESTABLISHED ACROSS THE ROCKIES.
&&
.DISCUSSION...
UPPER LOW CONTINUES TO SPIN ACROSS THE CENTRAL GULF OF CALIFORNIA
THIS MORNING. EXTENDING NORTHWARD FROM THE LOW INTO CENTRAL AZ IS AN
INVERTED TROUGH AND MCV...WHICH HAVE HELPED TO SUSTAIN A NOCTURNAL
MCS ACROSS THE LOWER DESERTS OF AZ. LATEST IR IMAGERY INDICATES THAT
CLOUD TOPS HAVE COOLED TO AS LOW AS -75C...WHICH CORRELATES TO TOPS
AROUND 40-45K FT...THOUGH KIWA RADAR SUGGESTS SOME OVERSHOOTING TOPS
MAY BE AS HIGH AS 55K FT. MUCH OF PHOENIX...NORTH SCOTTSDALE AND THE
WEST VALLEY RECEIVED MEASURABLE RAINFALL OVER THE PAST 6
HOURS...WITH SOME SPOTS MEASURING ALMOST AN INCH. WIDESPREAD SHOWER
AND THUNDERSTORM ACTIVITY CONTINUES AT THIS HOUR FROM MARICOPA
COUNTY WESTWARD...INCLUDING LA PAZ...YUMA AND RIVERSIDE COUNTIES. IT
IS EXPECTED THAT CONVECTION WILL CONTINUE TO DEVELOP EARLY THIS
MORNING ALONG OUTFLOW BOUNDARIES PROPAGATING INTO THE MOISTURE-RICH
ENVIRONMENT OF SW AZ AND SE CA. HEAVY RAINFALL AND MINOR FLOODING
ARE THE MAIN THREATS WITH THESE STORMS.
GLOBAL MODELS NOTORIOUSLY HAVE A DIFFICULT TIME INITIALIZING
PROPERLY WHEN THERE IS CONVECTION OVERNIGHT. FORECAST IS INSTEAD
WEIGHTED MORE TOWARDS THE HI-RES CONVECTIVE ALLOWING MODELS SUCH AS
THE WRF-NMM FOR SPC...WHICH HAS PICKED UP ON THE CURRENT ACTIVITY.
ALTHOUGH THE EASTERLY FLOW BETWEEN THE LOW TO THE SOUTH AND THE
ANTICYCLONE ACROSS NV WILL DIMINISH TODAY...SOUTH-CENTRAL AZ IS AGAIN
FAVORED FOR NOCTURNAL CONVECTION. CONDITIONS REMAIN SO ANOMALOUSLY
MOIST THAT MODELS SUCH AS THE HRRR SUGGEST THAT CONVECTION MAY
INITIATE AS EARLY AS THIS AFTERNOON. TEMPERATURES WILL ALSO BE
CONSIDERABLY LOWER TODAY...WITH HIGH TEMPERATURES STRUGGLING TO
REACH THE 100 DEGREE MARK IN THE LOWER DESERTS.
THE UPPER LOW ACROSS THE GOC IS EXPECTED TO LIFT NORTHWARD TO A
POSITION JUST WEST OF ROCKY POINT SUNDAY. THE THREAT OF SHOWERS AND
THUNDERSTORMS WILL PERSIST JUST ABOUT EVERYWHERE ACROSS THE FORECAST
AREA. POPS IN THE 12Z-18Z PERIOD SUNDAY WERE INCREASED...OWING TO
MUCH HIGHER PROBABILITIES FROM THE NMM-BASED GUIDANCE SUCH AS THE
SREF. WITH THE AMPLE MOISTURE AND SUBSEQUENT CLOUDINESS...AN
ADDITIONAL 3 TO 5 DEGREES OF COOLING IS ALSO ANTICIPATED.
EARLY NEXT WEEK...THE UPPER LOW WILL GET PICKED UP BY THE WESTERLIES
AS THE ANTICYCLONE SLIDES TOWARDS THE FOUR CORNERS. THE RESULTING
SOUTHWESTERLY FLOW WILL ADVECT DRIER AIR INITIALLY INTO SE CA AND SW
AZ...WHICH WILL CONFINE THE HIGHEST POPS TO HIGHER TERRAIN NORTH AND
EAST OF PHOENIX. THE RIDGE WILL BECOME REESTABLISHED ACROSS THE
SOUTHERN PLAINS THURSDAY...WHICH WILL ALLOW ANOTHER MOIST INVERTED
TROUGH TO APPROACH SOUTHERN AZ. CONSEQUENTLY...A RETURN TO NEAR CLIMO
POPS/TEMPS IS FORECAST FOR THE END OF THE WEEK.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL...
NEW STORMS CONTINUE TO DEVELOP OVER HIGHER TERRAIN EAST OF GLOBE.
ALTHOUGH SLOW TO MOVE WEST...MAY SEE EASTERLY OUTFLOW FROM THESE
STORMS AFFECTING KIWA LATER AFTER 11Z. OUTSIDE OF THIS ACTIVITY...
LIGHT WINDS AND SCT-BKN CLOUD DECKS GENERALLY AOA 10KFT ARE EXPECTED
ACROSS THE SOUTH-CENTRAL AZ DESERTS THIS MORNING. BY 20Z...STORMS
WILL AGAIN FORM OVER THE HIGHER TERRAIN NORTH AND EAST OF PHOENIX.
SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH...
SHOWER/THUNDERSTORM ACTIVITY WILL CONTINUE TO FILL IN OVER SOUTHEAST
CALIFORNIA THIS MORNING THROUGH AT LEAST 13Z...WITH GUSTY OUTFLOWS
UP TO 30KT POSSIBLE AT TIMES. SCT-BKN CLOUD DECKS GENERALLY AOA
10KFT WITH LOCAL CIGS DOWN TO 8KFT IN HEAVIER SHOWERS AND
THUNDERSTORMS...SKIES IMPROVING LATER THIS MORNING. WINDS SOUTHERLY
10-15KT THROUGH MUCH OF THE TAF PERIOD ACROSS THE LOWER COLORADO
RIVER VALLEY WITH LIGHTER SOUTHEASTERLY WINDS AT KIPL.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
ABOVE NORMAL PRECIP CHANCES WILL REMAIN A POSSIBILITY ON MONDAY AS A
AN AREA OF LOW PRESSURE EXISTS THE AREA. A SWITCH TO A SOUTHERLY
FLOW ALOFT WILL LIKELY BRING DRYING CONDITIONS AND ENDING
PRECIPITATION CHANCES ACROSS SOUTHEAST CALIFORNIA AND SOUTHWEST
ARIZONA FOR THE MIDDLE OF NEXT WEEK. HUMIDITIES WILL REMAIN ELEVATED
THROUGH THE ENTIRE PERIOD WITH AFTERNOON HUMIDITIES ONLY DROPPING
INTO THE 20-30 PERCENT RANGE WITH GOOD OVERNIGHT RECOVERY. STORM
COVERAGE AND INTENSITY WILL VARY FROM DAY TO DAY WHICH WILL IMPACT
FORECAST WINDS...POTENTIALLY DISRUPTING NORMAL DIURNAL PATTERNS.
$$
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...HIRSCH
AVIATION...MEYERS
FIRE WEATHER...KUHLMAN
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1107 AM EDT SAT JUL 20 2013
.SYNOPSIS...
ONE MORE HOT AND HUMID DAY IS EXPECTED TODAY ALONG WITH SCATTERED
STRONG TO SEVERE THUNDERSTORMS THIS AFTERNOON AS A COLD FRONT
APPROACHES FROM THE GREAT LAKES. THIS FRONT WILL BRING RELIEF FROM
THE EXCESSIVE HEAT AND HUMIDITY ON SUNDAY. MORE SEASONABLE BUT
HUMID CONDITIONS ARE EXPECTED FOR MUCH OF NEXT WEEK WITH
SCATTERED SHOWERS AND THUNDERSTORMS FROM TIME TO TIME.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1050 AM UPDATE...
NOTING A LOT OF SUBSIDENCE AND DRY AIR ALOFT WHICH IS TENDING TO
BREAK THE DEBRIS CLOUDS THAT HAVE MOVED ACROSS FROM NY STATE
EARLIER THIS MORNING ACROSS MOST OF THE REGION. ALSO NOTED AN AREA
OF SHOWERS THAT WORKED INTO NW MA/SW NH AROUND 14Z FROM NY STATE
TENDED TO DRY UP AS IT MOVED OUT OF THE BERKSHIRES. STARTING TO
SEE LINE OF SHOWERS/TSTMS STARTING TO DEVELOP ACROSS UPSTATE NY AS
WELL AS OVER S CENTRAL NY AT 1430Z.
HAVE UPDATED GRIDS TO SLOW DOWN THE PRECIP ESPECIALLY OVER EASTERN
AREAS UNTIL AROUND 18Z AND BEYOND. DEWPTS ARE MUCH HIGHER THAN
FORECAST...MAINLY IN THE MID 70S NEAR AND S OF THE MASS PIKE WHERE
THEY APPEAR TO BE POOLING...SO MAY BE A FOCUS OF ANY CONVECTION
THAT MAY DEVELOP PROBABLY AFTER 18Z. USED A BLEND OF OUR PREVIOUS
FORECAST WITH THE HRRR MODEL...WHICH APPEARS TO HAVE THIS SAME
FOCUS. OTHER CONVECTIVE PARAMETERS ARE MARGINAL...WITH MID LEVEL
LAPSE RATES ON ORDER OF 6C/KM...FOR LOW LEVEL LAPSE RATES ARE MUCH
HIGHER OVER CENTRAL AND EASTERN AREAS AS SEEN ON SPC MESO
ANALYSIS. SPC DID UPDATE THEIR CONVECTIVE OUTLOOK TO SHIFT IT A
BIT FURTHER S.
TEMPS ALSO A BIT HIGHER THAN FORECAST...WITH 92 AT 14Z AT KBOS.
HAVE ADJUSTED TEMPS A BIT HIGHER FROM PREVIOUS FORECAST. ALSO
ADJUSTED CLOUD COVER TO BRING CURRENT. REMAINDER OF FORECAST
LOOKED PRETTY GOOD BUT DID UPDATE TO BRING CURRENT.
PREVIOUS DISCUSSION...
THE BEST CHANCE FOR ORGANIZED STORMS AND SEVERE WEATHER WILL BE
IN WESTERN NEW ENGLAND AS 0-6KM SHEAR INCREASES TO 35 KT BY LATE
AFTERNOON...BUT BEST LOW LEVEL CONVERGENCE MAY BE FURTHER E NEAR
THE COASTAL PLAIN. PRIMARY MODE OF CONVECTION SHOULD BE
MULTICELLULAR LINE SEGMENTS WITH DAMAGING WIND THE GREATEST THREAT
FROM ANY SEVERE STORMS...ALONG WITH HEAVY DOWNPOURS IN HIGH PWAT
AIRMASS.
ANOTHER RATHER HOT AND HUMID DAY ACROSS SNE. IF THE CLOUD COVER
REMAIN BROKEN AND THIN...IT WONT TAKE MUCH FOR TEMPS TO SOAR INTO
THE LOW TO MID 90S AS IT IS ALREADY FAIRLY WARM PER THIS MORNING
LOWS. MAIN HEATING WILL BE ACROSS RI AND E MA WHERE MOST SUNSHINE
IS EXPECTED. DEWPOINTS IN THE LOWER-MID 70S WILL RESULT IN HEAT
INDICES OF 100-105 FOR HOTTEST SPOTS IN THE LOWER CT VALLEY AND
MUCH OF E MA AND RI WHERE HEAT ADVISORIES ARE IN EFFECT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
TONIGHT...
SCT SHOWERS AND TSTMS MAY LINGER ACROSS THE COASTAL PLAIN AND S
COAST INTO THE EVENING BEFORE ACTIVITY DISSIPATES AND MOVES
OFFSHORE. COLD FRONT WILL MOVE S ACROSS THE REGION TONIGHT BUT
NOT CLEARING THE S COAST UNTIL CLOSER TO 12Z SUN.
SUNDAY...
WEAK FRONT WILL STALL S OF NEW ENG WITH WEAK HIGH PRES BUILDING
TO THE N. WHILE IT WILL BE NOTICEABLY COOLER...850 MB TEMPS 14-16C
SO IT WILL STILL BE RATHER WARM WITH TEMPS IN THE MID TO UPPER
80S...COOLER HIGHER TERRAIN AS WELL AS IMMEDIATE COAST WHERE
COASTAL SEABREEZES ARE LIKELY. DEWPOINTS MAY DROP INTO THE UPPER
50S ACROSS N ZONES...BUT LIKELY REMAIN IN THE MID 60S CLOSER TO
THE COAST. LOW RISK FOR AN ISOLD SHOWER SUN AFTERNOON...OTHERWISE
DRY WEATHER WITH PT-MOSUNNY SKIES.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
HEADLINES...
* DRY AND SEASONABLE INTO MONDAY.
* SHOWERS AND THUNDERSTORMS RETURN FOR TUESDAY INTO WEDNESDAY.
* AN ACTIVE WEATHER PATTERN SETUP CONTINUES THROUGH THE LATE WEEK.
* NO SIGN OF OPPRESSIVE HEAT AND HUMIDITY RETURNING ANY TIME SOON.
*/OVERVIEW AND MODEL CONSENSUS...
WHILE BETTER CONTINUITY HAS EMERGED INTO THE MIDWEEK...THERE IS
STILL SOME UNCERTAINTY CONCERNING THE ABNORMAL SETUP SET TO EVOLVE
INTO THE LATTER PORTION OF THE FORECAST. LATEST OPERATIONAL RUNS OF
THE ECMWF HAVE COME INTO BETTER AGREEMENT WITH ITS ENSEMBLE MEAN
WHILE THE RUN-TO-RUN CONTINUITY OF THE GFS HAS NOT EXHIBITED THE
SAME.
AM IN FAVOR OF THE MORE AMPLIFIED PATTERN WITH THE BAROCLINIC ZONE
DIPPING INTO THE GULF COASTAL STATES AS EMPHASIZED BY THE ECMWF INTO
THE FOLLOWING WEEKEND. AGREE WITH WPC ASSESSMENT AND ACCOMPANYING
FORECAST GUIDANCE. THUS NOT SEEING A RETURN OF OPPRESSIVE HEAT AND
HUMIDITY ANY TIME SOON RATHER A MORE ACTIVE AND SEASONABLE PATTERN.
SURFACE OUTCOMES REMAIN UNCERTAIN SO FAR OUT IN THE FORECAST BUT IT
IS LIKELY THAT PACIFIC WAVES TRANSLATING AND EVOLVING THROUGH THE
LONG WAVE PATTERN WILL NOT ONLY AMPLIFY THE PATTERN BUT ALSO LEAD
TO SUCCESSIVE ROUNDS OF SHOWERS AND THUNDERSTORMS.
*/DAY-TO-DAY DETAILS...
*/SUNDAY NIGHT INTO MONDAY...
WILL KEEP THE FORECAST PERIOD MOSTLY DRY KEEPING COOLER AND DRIER
HIGH PRESSURE IN CONTROL. POOR MID-LEVEL LAPSE RATES. SUBSTANTIAL MID-
LEVEL DRY AIR IN PLACE WITH ACCOMPANYING RIDGING. LITTLE IN THE
WAY OF DYNAMICS AND ONLY LOW-LEVEL FORCING WILL BE ALONG SEA-
BREEZE FRONTS AS THE EARLY WEEKEND COLD FRONT WILL STALL SOUTH OF
NEW ENGLAND...ORIENTED WEST TO EAST IN PROXIMITY TO SOUTHERN
PA/NJ.
THERE ARE SUBTLE HINTS OF PERHAPS SOME PRECIPITATION...THE 20.0Z NAM
THE MOST PRONOUNCED SOLUTION. EVALUATING FURTHER...THE NORTHEASTERN
CONUS IS WITHIN THE RIGHT-REAR QUADRANT OF THE UPPER-LEVEL JET
COINCIDENT WITH THE MID-LEVEL /H85/ THERMAL GRADIENT. BUT WITH THE
DRY AIR AND POOR LAPSE RATES...JUST DO NOT HAVE THE CONFIDENCE IN
GOING WITH CHANCE POPS.
WILL KEEP CONDITIONS CLOSE TO SEASONABLE. BETTER CHANCE FOR
CLOUDS DURING THE PERIOD WILL BE ALONG THE SOUTH-COAST WITH CLOSER
PROXIMITY TO THE AFOREMENTIONED COLD FRONT.
*/MONDAY NIGHT INTO WEDNESDAY...
THERE IS BETTER AGREEMENT ON THE EVOLUTION OF PACIFIC DISTURBANCE
TRANSLATING THROUGH THE MARITIME FLOW AND INTERACTING WITH A STRONG
AREA OF LOW PRESSURE ACROSS NORTHERN QUEBEC. THE GENERAL THEME AT
THE SURFACE IS FOR AN AREA OF LOW PRESSURE TO DEVELOP NORTH OF THE
GREAT LAKES REGION...UNDERGO MATURATION AND OCCLUSION DURING THE
TIME FRAME INTO NORTHERN QUEBEC. THE SUBSEQUENT INFLUENCE OF RETURN
SOUTHERN FLOW ACROSS THE NORTHEASTERN CONUS LIFTS THE OFFSHORE FRONT
NORTH AS A WARM FRONT EARLY IN THE PERIOD...FOLLOWED BY A TRAILING
ATTENDANT COLD FRONT TO THE AFOREMENTIONED LOW LATE INTO WEDNESDAY.
WHILE SOME DIFFERENCES CONCERNING TIMING AND SUBSEQUENT SURFACE
OUTCOMES...THERE IS A GENERAL THEME OF PERIODS OF SHOWERS AND
THUNDERSTORMS LOCALIZED WHERE LOW-LEVEL CONVERGENCE ALONG FRONTAL
BOUNDARIES COUPLED WITH MID- TO UPPER-LEVEL DYNAMICS ALOFT
RESULTING IN DEEP-LAYER ASCENT. CHANCE POPS
WARRANTED...ESPECIALLY MONDAY NIGHT INTO TUESDAY NIGHT. SHEAR IS
PRONOUNCED...BUT INSTABILITY IS LACKING LIKELY DUE TO POOR MID-
LEVEL LAPSE RATES AND ANTICIPATED CLOUDY MESS. NOTED BY THE PRIOR
FORECASTER...HIGH PWATS UP TO 2 INCHES PRESENTS THE THREAT OF
HEAVY RAINFALL AND LOCALIZED FLOODING.
WILL PREVAIL WITH CONDITIONS AT OR SLIGHTLY ABOVE SEASONABLE WITH
EXPECTED SOUTHERLY FLOW. SHOULD SEE THE RETURN OF MUGGY CONDITIONS.
WINDS BACKING OUT OF THE NORTH-NORTHWEST AND WEAKENING TUESDAY NIGHT
INTO WEDNESDAY.
*/THURSDAY INTO THE WEEK...
GREATER CONFIDENCE TOWARDS THE DETERMINISTIC 19.12Z ECMWF WITH
IMPROVED AGREEMENT WITH ITS ENSEMBLE MEAN...AND BETTER RUN-TO-RUN
CONSISTENCY. STILL THERE IS SOME UNCERTAINTY WITH HOW PACIFIC ENERGY
EVOLVES THROUGH THE BASE OF THE BROADER TROUGHING PATTERN OVER THE
EASTERN TWO-THIRDS OF THE CONUS...THOUGH WPC/HPC HAS NOTED THAT
FORECAST GUIDANCE HAS TRENDED WITH A MORE AMPLIFIED TROUGH PATTERN
WITH A COLD UPPER-LOW DIPPING INTO THE GREAT LAKES REGION.
AS STATED YESTERDAY...CONTINUED CERTAINTY THAT THE NORTHEASTERN
CONUS REMAINS IN THE MARITIME FLOW RESULTING IN AN ACTIVE WEATHER
PATTERN AND SEASONABLE CONDITIONS. CHANCE POPS WARRANTED WITH THE
EXPECTATION FOR SHOWERS AND THUNDERSTORMS AT TIMES...NOT SPECULATING
ON SEVERE WEATHER AT THIS TIME...THOUGH IF THE TROUGH EFFECTIVELY
TAPS INTO TROPICAL MOISTURE...THEN HEAVY RAIN AND POTENTIAL FLOODING
WILL BE A CONCERN. WILL KEEP CONDITIONS AT SEASONABLE LEVELS.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
MODERATE CONFIDENCE THROUGH SUNDAY...
HAZE AND HIGH CLOUDS TO BE AN ISSUE THIS MORNING...GRADUALLY
BURNING OFF THROUGH THE DAY. EXPECTING AN INCREASE IN AREAL
COVERAGE OF SHRA/TSRA INTO THIS AFTERNOON ACROSS WESTERN AND
CENTRAL PORTIONS OF NEW ENGLAND. HAVE PREVAILED -SHRA VCTS
ACCORDINGLY MAINLY FOR THE AFTERNOON PERIOD AROUND THE MASS
TURNPIKE...SULKING SOUTH TO THE COAST TOWARDS SUNDOWN AND OUT TO
SEA INTO THE EVENING.
WITH ANY TSRA...LOW-VFR CIGS WITH MVFR/IFR VSBYS WILL BE
POSSIBLE. UNCERTAINTY ON LOCATION AND EVOLUTION OF TSRA SO DID NOT
PREVAIL IN THE TAF. GUSTY SW WINDS AHEAD OF AN APPROACHING COLD
FRONT ANTICIPATED TO SWEEP THROUGH THE TERMINALS LATE TONIGHT INTO
SUNDAY MORNING...WINDS BACKING OUT OF THE NORTH-NORTHWEST AND
WEAKENING.
COASTAL FOG MAY DEVELOP AHEAD OF THE COLD FRONT. SHOULD SEE
IMPROVEMENT THEREAFTER WITH DRIER AIR FILTERING IN. PREVAILING
VFR FOR SUNDAY WITH LIGHT NORTH-NORTHWEST WINDS...SEA-BREEZES
ALONG THE SHORES.
KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. WILL KEEP STORMS OUT
OF THE TERMINAL FOR NOW. GUSTY SOUTHWEST WINDS DURING THE DAY.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. PREVAILING -SHRA VCTS
WITH EXPECTATION OF AFTERNOON STORMS...BUT UNCERTAIN ON SPECIFIC
IMPACTS.
OUTLOOK...SUNDAY NIGHT INTO THURSDAY...
SUNDAY NIGHT INTO MONDAY...HIGH CONFIDENCE.
VFR. LIGHT AND VARIABLE WINDS. SEA-BREEZES ALONG THE SHORELINES.
MONDAY NIGHT INTO WEDNESDAY...MODERATE CONFIDENCE.
WINDS TURNING SOUTHERLY AND GUSTY AT TIMES. PERIODS OF SHRA/TSRA.
WILL SEE TEMPO MVFR-IFR IMPACTS WITH WET WEATHER. COULD SEE A
RETURN OF SOUTH-COASTAL DENSE FOG. COLD FRONT LATE IN THE PERIOD
WILL FORCE WINDS TO BACK NORTH-NORTHWEST.
THURSDAY...MODERATE CONFIDENCE.
AFOREMENTIONED COLD FRONT MAY LINGER IN PROXIMITY TO SOUTHERN NEW
ENGLAND ACTING AS A FOCUS FOR CONTINUED WET WEATHER AND PERHAPS MVFR-
IFR IMPACTS AT TIMES. COASTAL FOG MAY ALSO BE AN ISSUE ALONG THE
SOUTH-COAST.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
HIGH CONFIDENCE THROUGH SUNDAY.
THROUGH THIS EVENING...A FEW GUSTS TO 25 KT POSSIBLE OVER THE
NEARSHORE WATERS THIS AFTERNOON. SEAS REMAIN AROUND 5-6 FT ON THE
OPEN SOUTHERN WATERS AS WELL AS RI SOUND. SCT AFTN/EVENING TSTMS
POSSIBLE.
TONIGHT...SW WINDS WILL SHIFT TO THE NW LATE TONIGHT AS COLD FRONT
MOVES THROUGH. SCA SEAS CONTINUE OVER SOUTHERN WATERS. TSTMS
POSSIBLE SOUTH WATERS AS FRONTAL DEPARTS SLOWLY.
SUNDAY...E/SE WINDS DEVELOPING MAINLY UNDER 15 KT. SEAS SUBSIDING
BELOW SCA THRESHOLDS.
OUTLOOK...SUNDAY NIGHT INTO THURSDAY...
SUNDAY NIGHT INTO MONDAY...HIGH CONFIDENCE.
HIGH PRESSURE IN CONTROL. LIGHT AND VARIABLE WINDS GRADUALLY
BACKING OUT OF THE SOUTH. SEAS BELOW 5 FEET OVER ALL WATERS.
MONDAY NIGHT INTO WEDNESDAY...MODERATE CONFIDENCE.
INCREASE AREAL COVERAGE OF SHOWERS AND THUNDERSTORMS. WINDS OUT OF
THE SOUTH-SOUTHWEST INCREASING. GUSTS UP TO 20 KTS POSSIBLE. FETCH
RESULTING IN SEAS BUILDING ABOVE 5 FEET OVER THE SOUTH-SOUTHEAST
WATERS. COLD FRONT SLIDES INTO THE WATERS WEDNESDAY ALLOWING WINDS
TO DIMINISH. COASTAL FOG MAY BE AN ISSUE ALONG THE SOUTH-SHORE WITH
VISIBILITIES DOWN TO A QUARTER MILE OR LESS.
THURSDAY...MODERATE CONFIDENCE.
COLD FRONT WAVERS AS IT STALLS IN PROXIMITY TO SOUTHERN NEW ENGLAND.
CONTINUED CHANCES FOR SHOWERS AND THUNDERSTORMS CONTINUE. THE
LIGHTER WIND FLOW ALLOWS SEAS TO SUBSIDE. COASTAL FOG MAY CONTINUE
TO BE AN ISSUE WITH VISIBILITIES DOWN TO A QUARTER MILE OR LESS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR CTZ002>004.
MA...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR MAZ005>007-
011>021.
NH...NONE.
RI...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR RIZ001>005.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT SUNDAY FOR ANZ235-254.
SMALL CRAFT ADVISORY UNTIL 8 AM EDT SUNDAY FOR ANZ255-256.
&&
$$
SYNOPSIS...KJC/SIPPRELL
NEAR TERM...KJC/SIPPRELL/EVT
SHORT TERM...KJC
LONG TERM...SIPPRELL
AVIATION...KJC/SIPPRELL
MARINE...KJC/SIPPRELL/EVT
AREA FORECAST DISCUSSION
NWS TAUNTON MA
749 AM EDT SAT JUL 20 2013
.SYNOPSIS...
ONE MORE HOT AND HUMID DAY IS EXPECTED TODAY ALONG WITH SCATTERED
STRONG TO SEVERE THUNDERSTORMS THIS AFTERNOON AS A COLD FRONT
APPROACHES FROM THE GREAT LAKES. THIS FRONT WILL BRING RELIEF FROM
THE EXCESSIVE HEAT AND HUMIDITY ON SUNDAY. MORE SEASONABLE BUT
HUMID CONDITIONS ARE EXPECTED FOR MUCH OF NEXT WEEK WITH
SCATTERED SHOWERS AND THUNDERSTORMS FROM TIME TO TIME.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
730 AM UPDATE...
CONVECTION OVER THE EASTERN GREAT LAKES IS CERTAINLY GOING TO HAVE
CONSEQUENCES UPON THE REGIONS WEATHER. INCREASING CLOUD COVER IS
LIKELY TO LIMIT BOUNDARY LAYER DESTABILIZATION AND WARMING
TEMPERATURES AT THE SURFACE. ECHO PREVIOUS FORECASTERS THOUGHTS
ABOUT IMPACTS JUST TO HOW UNSTABLE IT GETS THIS AFTERNOON AND
POTENTIAL STRONG TO SEVERE WEATHER OUTCOMES.
FEEL THE LATEST HRRR AND THE WRF-ARW HAVE A GOOD HANDLE ON THE
PRESENT SITUATION. SHOWERS AND AN ISOLATED THUNDERSTORM ARE
POSSIBLE DURING THE MORNING HOURS. THIS ENERGY MAY DISSIPATE INTO
A SLIGHTLY DRIER AIRMASS PER THE 12Z CHATHAM SOUNDING. BUT AS ALSO
DISCERNED FROM THE CHATHAM SOUNDING...THERE IS A LOT OF POTENTIAL
INSTABILITY SHOULD THE BOUNDARY LAYER DESTABILIZE.
DIFFICULT TO PIN DOWN EXACTLY WHERE AND WHEN ANY THUNDERSTORMS
WILL DEVELOP AND EVOLVE FOR TODAY. AS NOTED BY THE PREVIOUS
FORECASTER...MLCAPES FORECAST TO REACH 1000-2000 J/KG BUT THERE
IS SOME UNCERTAINTY WITH THE AMOUNT OF SUNSHINE DUE TO CONVECTIVE
REMNANTS AND CLOUD COVER DRIFTING IN FROM THE WEST. MID-LEVEL
TEMPS ARE FORECAST TO BE ABOUT 3-4 DEGREES COOLER THAN YESTERDAY SO
THERE WILL BE MUCH LESS OF A CAP AND RIGHT ENTRANCE REGION OF
UPPER JET WILL BE APPROACHING FROM THE NORTH LATER TODAY.
FOCUS IS ON THE DEVELOPMENT OF A PRE-FRONTAL TROUGH AHEAD OF THE
MAIN SURFACE COLD FRONT WHICH MAY AID IN FOCUSING LOW LEVEL
CONVERGENCE FOR CONVECTION...THERE IS STILL AN EXPECTATION FOR
SCATTERED THUNDERSTORMS TO DEVELOP THIS AFTERNOON SHOULD CLOUD
COVER CLEAR OUT AS SUGGESTED BY THE HRRR.
AGAIN...THE BEST CHANCE FOR ORGANIZED STORMS AND SEVERE WEATHER
WILL BE IN WESTERN NEW ENGLAND AS 0-6KM SHEAR INCREASES TO 35 KT
BY LATE AFTERNOON...BUT BEST LOW LEVEL CONVERGENCE MAY BE FURTHER
E NEAR THE COASTAL PLAIN. PRIMARY MODE OF CONVECTION SHOULD BE
MULTICELLULAR LINE SEGMENTS WITH DAMAGING WIND THE GREATEST THREAT
FROM ANY SEVERE STORMS...ALONG WITH HEAVY DOWNPOURS IN HIGH PWAT
AIRMASS.
ANOTHER RATHER HOT AND HUMID DAY ACROSS SNE. IF THE CLOUD COVER
REMAIN BROKEN AND THIN...IT WONT TAKE MUCH FOR TEMPS TO SOAR INTO
THE LOW TO MID 90S AS IT IS ALREADY FAIRLY WARM PER THIS MORNING
LOWS. MAIN HEATING WILL BE ACROSS RI AND E MA WHERE MOST SUNSHINE
IS EXPECTED. DEWPOINTS 70-75 WILL RESULT IN HEAT INDICES OF 100-105
FOR HOTTEST SPOTS IN THE LOWER CT VALLEY AND MUCH OF E MA AND RI
WHERE HEAT ADVISORIES ARE IN EFFECT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
TONIGHT...
SCT SHOWERS AND TSTMS MAY LINGER ACROSS THE COASTAL PLAIN AND S
COAST INTO THE EVENING BEFORE ACTIVITY DISSIPATES AND MOVES
OFFSHORE. COLD FRONT WILL MOVE S ACROSS THE REGION TONIGHT BUT
NOT CLEARING THE S COAST UNTIL CLOSER TO 12Z SUN.
SUNDAY...
WEAK FRONT WILL STALL S OF NEW ENG WITH WEAK HIGH PRES BUILDING
TO THE N. WHILE IT WILL BE NOTICEABLY COOLER...850 MB TEMPS 14-16C
SO IT WILL STILL BE RATHER WARM WITH TEMPS IN THE MID TO UPPER
80S...COOLER HIGHER TERRAIN AS WELL AS IMMEDIATE COAST WHERE
COASTAL SEABREEZES ARE LIKELY. DEWPOINTS MAY DROP INTO THE UPPER
50S ACROSS N ZONES...BUT LIKELY REMAIN IN THE MID 60S CLOSER TO
THE COAST. LOW RISK FOR AN ISOLD SHOWER SUN AFTERNOON...OTHERWISE
DRY WEATHER WITH PT-MOSUNNY SKIES.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
HEADLINES...
* DRY AND SEASONABLE INTO MONDAY.
* SHOWERS AND THUNDERSTORMS RETURN FOR TUESDAY INTO WEDNESDAY.
* AN ACTIVE WEATHER PATTERN SETUP CONTINUES THROUGH THE LATE WEEK.
* NO SIGN OF OPPRESSIVE HEAT AND HUMIDITY RETURNING ANY TIME SOON.
*/OVERVIEW AND MODEL CONSENSUS...
WHILE BETTER CONTINUITY HAS EMERGED INTO THE MIDWEEK...THERE IS
STILL SOME UNCERTAINTY CONCERNING THE ABNORMAL SETUP SET TO EVOLVE
INTO THE LATTER PORTION OF THE FORECAST. LATEST OPERATIONAL RUNS OF
THE ECMWF HAVE COME INTO BETTER AGREEMENT WITH ITS ENSEMBLE MEAN
WHILE THE RUN-TO-RUN CONTINUITY OF THE GFS HAS NOT EXHIBITED THE
SAME.
AM IN FAVOR OF THE MORE AMPLIFIED PATTERN WITH THE BAROCLINIC ZONE
DIPPING INTO THE GULF COASTAL STATES AS EMPHASIZED BY THE ECMWF INTO
THE FOLLOWING WEEKEND. AGREE WITH WPC ASSESSMENT AND ACCOMPANYING
FORECAST GUIDANCE. THUS NOT SEEING A RETURN OF OPPRESSIVE HEAT AND
HUMIDITY ANY TIME SOON RATHER A MORE ACTIVE AND SEASONABLE PATTERN.
SURFACE OUTCOMES REMAIN UNCERTAIN SO FAR OUT IN THE FORECAST BUT IT
IS LIKELY THAT PACIFIC WAVES TRANSLATING AND EVOLVING THROUGH THE
LONGWAVE PATTERN WILL NOT ONLY AMPLIFY THE PATTERN BUT ALSO LEAD TO
SUCCESSIVE ROUNDS OF SHOWERS AND THUNDERSTORMS.
*/DAY-TO-DAY DETAILS...
*/SUNDAY NIGHT INTO MONDAY...
WILL KEEP THE FORECAST PERIOD MOSTLY DRY KEEPING COOLER AND DRIER
HIGH PRESSURE IN CONTROL. POOR MID-LEVEL LAPSE RATES. SUBSTANTIAL MID-
LEVEL DRY AIR IN PLACE WITH ACCOMPANYING RIDGING. LITTLE IN THE
WAY OF DYNAMICS AND ONLY LOW-LEVEL FORCING WILL BE ALONG SEA-
BREEZE FRONTS AS THE EARLY WEEKEND COLD FRONT WILL STALL SOUTH OF
NEW ENGLAND...ORIENTED WEST TO EAST IN PROXIMITY TO SOUTHERN
PA/NJ.
THERE ARE SUBTLE HINTS OF PERHAPS SOME PRECIPITATION...THE 20.0Z NAM
THE MOST PRONOUNCED SOLUTION. EVALUATING FURTHER...THE NORTHEASTERN
CONUS IS WITHIN THE RIGHT-REAR QUADRANT OF THE UPPER-LEVEL JET
COINCIDENT WITH THE MID-LEVEL /H85/ THERMAL GRADIENT. BUT WITH THE
DRY AIR AND POOR LAPSE RATES...JUST DO NOT HAVE THE CONFIDENCE IN
GOING WITH CHANCE POPS.
WILL KEEP CONDITIONS CLOSE TO SEASONABLE. BETTER CHANCE FOR
CLOUDS DURING THE PERIOD WILL BE ALONG THE SOUTH-COAST WITH CLOSER
PROXIMITY TO THE AFOREMENTIONED COLD FRONT.
*/MONDAY NIGHT INTO WEDNESDAY...
THERE IS BETTER AGREEMENT ON THE EVOLUTION OF PACIFIC DISTURBANCE
TRANSLATING THROUGH THE MARITIME FLOW AND INTERACTING WITH A STRONG
AREA OF LOW PRESSURE ACROSS NORTHERN QUEBEC. THE GENERAL THEME AT
THE SURFACE IS FOR AN AREA OF LOW PRESSURE TO DEVELOP NORTH OF THE
GREAT LAKES REGION...UNDERGO MATURATION AND OCCLUSION DURING THE
TIME FRAME INTO NORTHERN QUEBEC. THE SUBSEQUENT INFLUENCE OF RETURN
SOUTHERN FLOW ACROSS THE NORTHEASTERN CONUS LIFTS THE OFFSHORE FRONT
NORTH AS A WARM FRONT EARLY IN THE PERIOD...FOLLOWED BY A TRAILING
ATTENDANT COLD FRONT TO THE AFOREMENTIONED LOW LATE INTO WEDNESDAY.
WHILE SOME DIFFERENCES CONCERNING TIMING AND SUBSEQUENT SURFACE
OUTCOMES...THERE IS A GENERAL THEME OF PERIODS OF SHOWERS AND
THUNDERSTORMS LOCALIZED WHERE LOW-LEVEL CONVERGENCE ALONG FRONTAL
BOUNDARIES COUPLED WITH MID- TO UPPER-LEVEL DYNAMICS ALOFT
RESULTING IN DEEP-LAYER ASCENT. CHANCE POPS
WARRANTED...ESPECIALLY MONDAY NIGHT INTO TUESDAY NIGHT. SHEAR IS
PRONOUNCED...BUT INSTABILITY IS LACKING LIKELY DUE TO POOR MID-
LEVEL LAPSE RATES AND ANTICIPATED CLOUDY MESS. NOTED BY THE PRIOR
FORECASTER...HIGH PWATS UP TO 2 INCHES PRESENTS THE THREAT OF
HEAVY RAINFALL AND LOCALIZED FLOODING.
WILL PREVAIL WITH CONDITIONS AT OR SLIGHTLY ABOVE SEASONABLE WITH
EXPECTED SOUTHERLY FLOW. SHOULD SEE THE RETURN OF MUGGY CONDITIONS.
WINDS BACKING OUT OF THE NORTH-NORTHWEST AND WEAKENING TUESDAY NIGHT
INTO WEDNESDAY.
*/THURSDAY INTO THE WEEK...
GREATER CONFIDENCE TOWARDS THE DETERMINISTIC 19.12Z ECMWF WITH
IMPROVED AGREEMENT WITH ITS ENSEMBLE MEAN...AND BETTER RUN-TO-RUN
CONSISTENCY. STILL THERE IS SOME UNCERTAINTY WITH HOW PACIFIC ENERGY
EVOLVES THROUGH THE BASE OF THE BROADER TROUGHING PATTERN OVER THE
EASTERN TWO-THIRDS OF THE CONUS...THOUGH WPC/HPC HAS NOTED THAT
FORECAST GUIDANCE HAS TRENDED WITH A MORE AMPLIFIED TROUGH PATTERN
WITH A COLD UPPER-LOW DIPPING INTO THE GREAT LAKES REGION.
AS STATED YESTERDAY...CONTINUED CERTAINTY THAT THE NORTHEASTERN
CONUS REMAINS IN THE MARITIME FLOW RESULTING IN AN ACTIVE WEATHER
PATTERN AND SEASONABLE CONDITIONS. CHANCE POPS WARRANTED WITH THE
EXPECTATION FOR SHOWERS AND THUNDERSTORMS AT TIMES...NOT SPECULATING
ON SEVERE WEATHER AT THIS TIME...THOUGH IF THE TROUGH EFFECTIVELY
TAPS INTO TROPICAL MOISTURE...THEN HEAVY RAIN AND POTENTIAL FLOODING
WILL BE A CONCERN. WILL KEEP CONDITIONS AT SEASONABLE LEVELS.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
MODERATE CONFIDENCE THROUGH SUNDAY...
HAZE AND HIGH CLOUDS TO BE AN ISSUE THIS MORNING...GRADUALLY
BURNING OFF THROUGH THE DAY. EXPECTING AN INCREASE IN AREAL
COVERAGE OF SHRA/TSRA INTO THIS AFTERNOON ACROSS WESTERN AND
CENTRAL PORTIONS OF NEW ENGLAND. HAVE PREVAILED -SHRA VCTS
ACCORDINGLY MAINLY FOR THE AFTERNOON PERIOD AROUND THE MASS
TURNPIKE...SULKING SOUTH TO THE COAST TOWARDS SUNDOWN AND OUT TO
SEA INTO THE EVENING.
WITH ANY TSRA...LOW-VFR CIGS WITH MVFR/IFR VSBYS WILL BE
POSSIBLE. UNCERTAINTY ON LOCATION AND EVOLUTION OF TSRA SO DID NOT
PREVAIL IN THE TAF. GUSTY SW WINDS AHEAD OF AN APPROACHING COLD
FRONT ANTICIPATED TO SWEEP THROUGH THE TERMINALS LATE TONIGHT INTO
SUNDAY MORNING...WINDS BACKING OUT OF THE NORTH-NORTHWEST AND
WEAKENING.
COASTAL FOG MAY DEVELOP AHEAD OF THE COLD FRONT. SHOULD SEE
IMPROVEMENT THEREAFTER WITH DRIER AIR FILTERING IN. PREVAILING
VFR FOR SUNDAY WITH LIGHT NORTH-NORTHWEST WINDS...SEA-BREEZES
ALONG THE SHORES.
KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. WILL KEEP STORMS OUT
OF THE TERMINAL FOR NOW. GUSTY SOUTHWEST WINDS DURING THE DAY.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. PREVAILING -SHRA VCTS
WITH EXPECTATION OF AFTERNOON STORMS...BUT UNCERTAIN ON SPECIFIC
IMPACTS.
OUTLOOK...SUNDAY NIGHT INTO THURSDAY...
SUNDAY NIGHT INTO MONDAY...HIGH CONFIDENCE.
VFR. LIGHT AND VARIABLE WINDS. SEA-BREEZES ALONG THE SHORELINES.
MONDAY NIGHT INTO WEDNESDAY...MODERATE CONFIDENCE.
WINDS TURNING SOUTHERLY AND GUSTY AT TIMES. PERIODS OF SHRA/TSRA.
WILL SEE TEMPO MVFR-IFR IMPACTS WITH WET WEATHER. COULD SEE A
RETURN OF SOUTH-COASTAL DENSE FOG. COLD FRONT LATE IN THE PERIOD
WILL FORCE WINDS TO BACK NORTH-NORTHWEST.
THURSDAY...MODERATE CONFIDENCE.
AFOREMENTIONED COLD FRONT MAY LINGER IN PROXIMITY TO SOUTHERN NEW
ENGLAND ACTING AS A FOCUS FOR CONTINUED WET WEATHER AND PERHAPS MVFR-
IFR IMPACTS AT TIMES. COASTAL FOG MAY ALSO BE AN ISSUE ALONG THE
SOUTH-COAST.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
HIGH CONFIDENCE THROUGH SUNDAY.
TODAY...A FEW GUSTS TO 25 KT POSSIBLE OVER THE NEARSHORE WATERS
THIS AFTERNOON. SCA SEAS OVER THE OPEN SOUTHERN WATERS. SCT
AFTN/EVENING TSTMS POSSIBLE.
TONIGHT...SW WINDS WILL SHIFT TO THE NW LATE TONIGHT AS COLD FRONT
MOVES THROUGH. SCA SEAS CONTINUE OVER SOUTHERN WATERS. TSTMS
POSSIBLE SOUTH WATERS AS FRONTAL DEPARTS SLOWLY.
SUNDAY...E/SE WINDS DEVELOPING MAINLY UNDER 15 KT. SEAS SUBSIDING
BELOW SCA THRESHOLDS.
OUTLOOK...SUNDAY NIGHT INTO THURSDAY...
SUNDAY NIGHT INTO MONDAY...HIGH CONFIDENCE.
HIGH PRESSURE IN CONTROL. LIGHT AND VARIABLE WINDS GRADUALLY
BACKING OUT OF THE SOUTH. SEAS BELOW 5 FEET OVER ALL WATERS.
MONDAY NIGHT INTO WEDNESDAY...MODERATE CONFIDENCE.
INCREASE AREAL COVERAGE OF SHOWERS AND THUNDERSTORMS. WINDS OUT OF
THE SOUTH-SOUTHWEST INCREASING. GUSTS UP TO 20 KTS POSSIBLE. FETCH
RESULTING IN SEAS BUILDING ABOVE 5 FEET OVER THE SOUTH-SOUTHEAST
WATERS. COLD FRONT SLIDES INTO THE WATERS WEDNESDAY ALLOWING WINDS
TO DIMINISH. COASTAL FOG MAY BE AN ISSUE ALONG THE SOUTH-SHORE WITH
VISIBILITIES DOWN TO A QUARTER MILE OR LESS.
THURSDAY...MODERATE CONFIDENCE.
COLD FRONT WAVERS AS IT STALLS IN PROXIMITY TO SOUTHERN NEW ENGLAND.
CONTINUED CHANCES FOR SHOWERS AND THUNDERSTORMS CONTINUE. THE
LIGHTER WIND FLOW ALLOWS SEAS TO SUBSIDE. COASTAL FOG MAY CONTINUE
TO BE AN ISSUE WITH VISIBILITIES DOWN TO A QUARTER MILE OR LESS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...HEAT ADVISORY FROM NOON TODAY TO 7 PM EDT THIS EVENING FOR
CTZ002>004.
MA...HEAT ADVISORY FROM NOON TODAY TO 7 PM EDT THIS EVENING FOR
MAZ005>007-011>021.
NH...NONE.
RI...HEAT ADVISORY FROM NOON TODAY TO 7 PM EDT THIS EVENING FOR
RIZ001>005.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT SUNDAY FOR ANZ235-254.
SMALL CRAFT ADVISORY UNTIL 8 AM EDT SUNDAY FOR ANZ255-256.
&&
$$
SYNOPSIS...KJC/SIPPRELL
NEAR TERM...KJC/SIPPRELL
SHORT TERM...KJC
LONG TERM...SIPPRELL
AVIATION...KJC/SIPPRELL
MARINE...KJC/SIPPRELL
AREA FORECAST DISCUSSION
NWS WICHITA KS
1008 AM CDT SAT JUL 20 2013
.UPDATE...
ISSUED AT 1001 AM CDT SAT JUL 20 2013
ISOLATED SHRA/TSRA HAVE DISSIPATED FOR THE MOST PART...THOUGH A ANOTHER
POCKET BUMBLING UP ACROSS THE NORTHEAST FRINGES OF FLINT HILLS. TRENDED
POPS DOWN...AND TRIED TO ACCOUNT FOR ADVECTION AS WELL. HOURLY
TEMPERATURE TRENDS ALSO ON TRACK MORE OR LESS...BUT HAD TO ADJUST DEWPOINTS
SLIGHTLY UP IN SOME LOCATIONS AND DOWN IN OTHERS. OTHERWISE MAX
TEMP AND OTHER SENSIBLE WEATHER FORECASTS LOOK ON TRACK.
SF
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 344 AM CDT SAT JUL 20 2013
TODAY-TONIGHT:
LOW CONFIDENCE FORECAST WITH SHORT TERM/HIGH RESOLUTION GUIDANCE
SHOWING MANY POSSIBLE SCENARIOS AND MOST HAVE BEEN STRUGGLING OUT
OF THE BOX. HAVE USED A COMBO OF HRRR AND ECMWF AS BOTH NAM/GFS
SEEM QUITE OPTIMISTIC WITH CAPE/PRECIPITATION FOR LATER TODAY.
WEAK FLOW ALOFT MAKES IT HARD TO DETERMINE WHERE THINGS WILL MOVE
AND GIVEN WEAK FORCING...BOUNDARIES WILL LIKELY BE THE KEY TO
CONVECTIVE INITIATION. AT THIS TIME...THINKING WEAK SURFACE
BOUNDARY FROM GBD-RSL-MHK WILL LIKELY NOT MOVE VERY MUCH...SO WILL
DRIBBLE ISOLATED POPS ALONG/NORTH OF BOUNDARY THIS MORNING.
CHANCES SHOULD INCREASE A BIT LATE AFTERNOON BUT MORE LIKELY THIS
EVENING. ECMWF KEEPS THE BULK OF THE PRECIPITATION IN CENTRAL KS
OVERNIGHT AND POPS MAY BE OVERDONE ACROSS THE SOUTHERN HALF OF THE
AREA.
SUN-MON:
BETTER UPPER FORCING IS ANTICIPATED AS DAY WEARS ON SUN BUT
FORECAST IS COMPLICATED BY POSSIBLE OUTFLOW FROM STORMS OVER NE KS
IN THE MORNING. SUSPECT ANOTHER ROUND OF STORMS WILL DEVELOP IN
NORTHWEST FLOW AND MOVE ACROSS FLINT HILLS/SOUTHEAST KS SUN NIGHT.
THIS SHOULD EXIT SOUTHEAST KS AROUND SUNRISE. MAY SEE SOME
INCREASE IN CAPPING ON MON AND GIVEN LESS FORCING...PRECIPITATION
CHANCES SHOULD DIMINISH. SHADED TEMPERATURES DOWN A BIT IN THE
EASTERN HALF AND WARMER IN WEST BASED ON CLOUDS BOTH DAYS.
-HOWERTON
.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 344 AM CDT SAT JUL 20 2013
AGAIN FAIRLY GOOD AGREEMENT BETWEEN 0000 UTC RUNS OF GFS/ECMWF
OVERALL PATTERN UNTIL FRI. HOWEVER DETAILS ON PRECIPITATION CHANCES
ARE STILL IN LESS AGREEMENT AND COMBINED WITH GRID INITIALIZATION
ISSUES...WILL END UP WITH CONSIDERABLE PRECIPITATION MENTIONED THIS
PERIOD. STILL APPEARS TO BE AN INCREASED CHANCE FOR PRECIPITATION
TUE NIGHT AS SHORTWAVE MOVES DOWN NORTHWEST FLOW. SURFACE FRONT
MAY BE MOVING INTO THE AREA ON FRI...BUT UNCERTAINTY IS HIGH ON
TIMING. -HOWERTON
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 628 AM CDT SAT JUL 20 2013
ISOLATED SHOWERS WERE ONGOING ACROSS MAINLY CENTRAL KANSAS
IMPACTING KRSL AND KSLN. THIS ACTIVTY IS EXPECTED TO DRIFT NORTH
AND DIMINISH BY AROUND 14Z. WIDELY SCATTERED SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO REDEVELOP ACROSS THE AREA THIS
AFTERNOON AND FESTER INTO THE OVERNIGHT HOURS. TRANSIENT MVFR WILL
REMAIN POSSIBLE UNDER THE HEAVIER ACTIVITY WHILE VFR PREVAILS
ACROSS THE FORECAST AREA. LIGHT AND VARIABLE WINDS WILL BECOME
SOUTH TO SOUTHEAST BY MID-MORNING AT SPEEDS AROUND 15 MPH
ANTICIPATED.
MWM
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 96 72 93 73 / 20 20 20 20
HUTCHINSON 95 70 94 71 / 20 20 20 20
NEWTON 93 70 92 70 / 20 30 30 20
ELDORADO 94 71 92 70 / 20 20 30 30
WINFIELD-KWLD 96 73 93 74 / 20 20 20 20
RUSSELL 94 67 98 68 / 30 30 20 20
GREAT BEND 94 66 97 68 / 20 20 20 20
SALINA 95 70 94 71 / 30 40 40 30
MCPHERSON 95 70 94 70 / 30 30 30 20
COFFEYVILLE 97 72 94 72 / 20 20 20 40
CHANUTE 94 71 92 71 / 20 30 30 40
IOLA 93 71 91 71 / 30 30 40 40
PARSONS-KPPF 96 72 93 71 / 20 20 30 40
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
631 AM CDT SAT JUL 20 2013
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 344 AM CDT SAT JUL 20 2013
TODAY-TONIGHT:
LOW CONFIDENCE FORECAST WITH SHORT TERM/HIGH RESOLUTION GUIDANCE
SHOWING MANY POSSIBLE SCENARIOS AND MOST HAVE BEEN STRUGGLING OUT
OF THE BOX. HAVE USED A COMBO OF HRRR AND ECMWF AS BOTH NAM/GFS
SEEM QUITE OPTIMISTIC WITH CAPE/PRECIPITATION FOR LATER TODAY.
WEAK FLOW ALOFT MAKES IT HARD TO DETERMINE WHERE THINGS WILL MOVE
AND GIVEN WEAK FORCING...BOUNDARIES WILL LIKELY BE THE KEY TO
CONVECTIVE INITIATION. AT THIS TIME...THINKING WEAK SURFACE
BOUNDARY FROM GBD-RSL-MHK WILL LIKELY NOT MOVE VERY MUCH...SO WILL
DRIBBLE ISOLATED POPS ALONG/NORTH OF BOUNDARY THIS MORNING.
CHANCES SHOULD INCREASE A BIT LATE AFTERNOON BUT MORE LIKELY THIS
EVENING. ECMWF KEEPS THE BULK OF THE PRECIPITATION IN CENTRAL KS
OVERNIGHT AND POPS MAY BE OVERDONE ACROSS THE SOUTHERN HALF OF THE
AREA.
SUN-MON:
BETTER UPPER FORCING IS ANTICIPATED AS DAY WEARS ON SUN BUT
FORECAST IS COMPLICATED BY POSSIBLE OUTFLOW FROM STORMS OVER NE KS
IN THE MORNING. SUSPECT ANOTHER ROUND OF STORMS WILL DEVELOP IN
NORTHWEST FLOW AND MOVE ACROSS FLINT HILLS/SOUTHEAST KS SUN NIGHT.
THIS SHOULD EXIT SOUTHEAST KS AROUND SUNRISE. MAY SEE SOME
INCREASE IN CAPPING ON MON AND GIVEN LESS FORCING...PRECIPITATION
CHANCES SHOULD DIMINISH. SHADED TEMPERATURES DOWN A BIT IN THE
EASTERN HALF AND WARMER IN WEST BASED ON CLOUDS BOTH DAYS.
-HOWERTON
.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 344 AM CDT SAT JUL 20 2013
AGAIN FAIRLY GOOD AGREEMENT BETWEEN 0000 UTC RUNS OF GFS/ECMWF
OVERALL PATTERN UNTIL FRI. HOWEVER DETAILS ON PRECIPITATION CHANCES
ARE STILL IN LESS AGREEMENT AND COMBINED WITH GRID INITIALIZATION
ISSUES...WILL END UP WITH CONSIDERABLE PRECIPITATION MENTIONED THIS
PERIOD. STILL APPEARS TO BE AN INCREASED CHANCE FOR PRECIPITATION
TUE NIGHT AS SHORTWAVE MOVES DOWN NORTHWEST FLOW. SURFACE FRONT
MAY BE MOVING INTO THE AREA ON FRI...BUT UNCERTAINTY IS HIGH ON
TIMING. -HOWERTON
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 628 AM CDT SAT JUL 20 2013
ISOLATED SHOWERS WERE ONGOING ACROSS MAINLY CENTRAL KANSAS
IMPACTING KRSL AND KSLN. THIS ACTIVTY IS EXPECTED TO DRIFT NORTH
AND DIMINISH BY AROUND 14Z. WIDELY SCATTERED SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO REDEVELOP ACROSS THE AREA THIS
AFTERNOON AND FESTER INTO THE OVERNIGHT HOURS. TRANSIENT MVFR WILL
REMAIN POSSIBLE UNDER THE HEAVIER ACTIVITY WHILE VFR PREVAILS
ACROSS THE FORECAST AREA. LIGHT AND VARIABLE WINDS WILL BECOME
SOUTH TO SOUTHEAST BY MID-MORNING AT SPEEDS AROUND 15 MPH
ANTICIPATED.
MWM
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 96 72 93 73 / 20 20 20 20
HUTCHINSON 95 70 94 71 / 20 20 20 20
NEWTON 93 70 92 70 / 20 30 30 20
ELDORADO 94 71 92 70 / 20 20 30 30
WINFIELD-KWLD 96 73 93 74 / 20 20 20 20
RUSSELL 94 67 98 68 / 30 30 20 20
GREAT BEND 94 66 97 68 / 20 20 20 20
SALINA 95 70 94 71 / 30 40 40 30
MCPHERSON 95 70 94 70 / 30 30 30 20
COFFEYVILLE 97 72 94 72 / 20 20 20 40
CHANUTE 94 71 92 71 / 20 30 30 40
IOLA 93 71 91 71 / 30 30 40 40
PARSONS-KPPF 96 72 93 71 / 20 20 30 40
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
606 AM CDT SAT JUL 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT SAT JUL 20 2013
TODAY AND TONIGHT...A LONGER WAVE LENGTH UPPER LEVEL TROUGH WILL
CONTINUE TO AMPLIFY ACROSS THE UPPER MIDWEST AND GREAT LAKES STATES.
THIS WILL CAUSE THE UPPER FLOW ACROSS THE PLAINS TO BECOME
NORTHWESTERLY. SHORTER WAVE LENGTH UPPER LEVEL TROUGHS WILL ROUND
THE UPPER RIDGE AXIS ACROSS THE WESTERN CONUS AND DIG SOUTHEAST
ACROSS THE CENTRAL PLAINS THROUGH TONIGHT. A WEAK FRONTAL BOUNDARY
WAS LOCATED FROM SOUTHWEST KS...NORTHEAST TO NEAR TOP...THEN
NORTHEAST ACROSS NORTHERN MO. WEAK ISENTROPIC LIFT NORTH OF THE
BOUNDARY MAY CAUSE A FEW SHOWERS TO DEVELOP THIS MORNING ACROSS EAST
CENTRAL KS.
MOST NUMERICAL MODELS SHOW AN H5 TROUGH DIGGING SOUTHEAST ACROSS
CENTRAL HIGH PLAINS DURING THE AFTERNOON HOURS. THE ASCENT AHEAD OF
THE H5 TROUGH COMBINED WITH UPSLOPE FLOW WILL CAUSE A COMPLEX OF
THUNDERSTORMS TO DEVELOP ACROSS WESTERN NE LATE THIS AFTERNOON AND
EARLY EVENING...THEN MOVE SOUTHEAST ACROSS EASTERN KS LATER TONIGHT.
ISOLATED TO WIDELY SCATTERED THUNDERSTORMS MAY ALSO DEVELOP ALONG
THE NORTHWARD MOVING FRONTAL BOUNDARY ACROSS THE CWA DURING THE LATE
AFTERNOON AND EARLY EVENING HOURS. THE 00Z NAM AND RAP MODELS WERE
SHOWING 1500-2500 J/KG OF MLCAPE. HOWEVER...THE SFC-6KM EFFECTIVE
SHEAR WILL ONLY BE 15 TO 20 KTS DURING THE AFTERNOON AND EARLY
EVENING HOURS. DUE TO THE WEAKER VERTICAL WINDSHEAR UPDRAFTS WILL
PROBABLY NOT BE ABLE TO SUSTAIN THEIR INTENSITY FOR MORE THAN 15 TO
20 MINUTES. THE STRONGER THUNDERSTORMS MAY PRODUCE SMALL HAIL AND 40
TO 50 MPH WINDS GUSTS. A STORM OR TWO MAY BRIEFLY PRODUCE QUARTER
SIZE HAIL AND 58 MPH WINDS GUSTS.
THE INSTABILITY AND VERTICAL WIND SHEAR AND INSTABILITY LOOKS TOO
WEAK FOR THE COMPLEX OF THUNDERSTORMS LATE TONIGHT TO BE
SEVERE...SOME OF THE STRONGER STORMS MAY PRODUCE GUSTY WINDS AND
THERE COULD BE HEAVY RAINFALL ALONG THE TRACK OF THE THUNDERSTORM
COMPLEX. I KEPT LIKELY POPS FOR THE NORTHERN AND EASTERN COUNTIES OF
THE CWA AFTER MIDNIGHT. THIS MAY CHANGE DEPENDING TO WHERE THE MCS
ACROSS NE FORMS AND HOW IT TRACKS THROUGH THE NIGHT. ATTM...MOST
MODELS HAVE THE COMPLEX OF STORMS MOVING SOUTHEAST ACROSS SOUTH
CENTRAL NE AND ACROSS THE EASTERN CWA LATE TONIGHT AND THROUGH THE
MORNING HOURS OF SUNDAY.
BROKEN TO SCATTED CLOUD COVER AND LIGHT SOUTHEAST WINDS WILL KEEP
HIGH TEMPERATURES TODAY IN THE LOWER TO MID 90S ACROSS THE CWA.
HIGHER SURFACE DEWPOINTS IN THE MID TO UPPER 60S WILL CAUSE HEAT
INDICES TO RISE INTO THE UPPER 90S.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 350 AM CDT SAT JUL 20 2013
THE COMBINATION OF PERSISTENT UPPER RIDGING IN THE INTERMOUNTAIN
WEST AND TROUGHING IN THE GREAT LAKES AREA WILL PRIMARILY KEEP THE
COUNTY WARNING AREA IN NORTHWEST FLOW ALOFT THROUGH THE END OF THE
UPCOMING WORK WEEK. IN GENERAL THIS WILL KEEP AN AXIS OF LOW LEVEL
MOISTURE IN PLACE FROM KS WEST AND NORTHWESTWARD INTO THE CENTRAL
HIGH PLAINS THROUGH THE PERIOD. AS A SERIES OF SHORTWAVE TROUGHS
MOVING THROUGH THE FLOW ALOFT...THERE WILL BE (DEPENDING ON THE
TIMING OF EACH SHORTWAVE) THE OPPORTUNITY FOR CONVECTION TO DEVELOP
AND MOVE EAST AND SOUTHEAST WITHIN THIS MOISTURE AXIS...ALTHOUGH THE
LLVL JET WILL NOT BE PARTICULARLY STRONG THIS SETUP ALONG WITH
POSSIBLE OUTFLOW/WEAK FRONTAL BOUNDARIES FROM EARLIER MCS`S SHOULD
PROVIDE SEVERAL OPPORTUNITIES FOR RAIN IN THE WEEK AHEAD. ALTHOUGH
THE MODELS OFFER DIFFERENT SOLUTIONS ON THE STRENGTH AND TIMING OF
THESE SHORTWAVE TROUGHS...THE BETTER CHANCES FOR THUNDERSTORMS
APPEARS TO BE SUNDAY INTO SUNDAY NIGHT WITH THE PASSAGE OF A
SHORTWAVE TROUGH...THEN AGAIN WITH AN STRONGER WAVE TUESDAY NIGHT
INTO WEDNESDAY MORNING. FOCUSED THE HIGHER POPS IN THESE PERIODS
WHERE PERSISTENT AND CONFIDENCE IS HIGHER. MESOSCALE FEATURES WITH
ANY MCS`S WILL LIKELY COMPLICATE THE FORECAST FROM DAY TO DAY.
ANOTHER CHALLENGE THIS WEEK IN THIS PATTERN WILL BE TEMPERATURES
AS THE CWA WILL FREQUENTLY BE LOCATED ON THE EASTERN PERIPHERY OF A
STRONG THERMAL AXIS MUCH OF THE WEEK. AS THE LLVL FLOW VEERS...THERE
WILL BE AN ENHANCED OPPORTUNITY FOR VERY WARM AIR TO BE ADVECTED
EASTWARD INTO THE CWA. THIS OCCURS ON MONDAY INTO TUESDAY...WITH
SOME INDICATIONS OF ANOTHER SURGE OF MUCH WARMER AIR TOWARDS THE END
OF THE WEEK. HOWEVER...PERIODIC CHANCES FOR PRECIP/THICKER CLOUDS
WILL CONTINUE TO BE POSSIBLE OFFSETTING FACTORS. WILL MAINTAIN
HIGHS GENERALLY IN THE 90S THROUGH THE FCST...ALTHOUGH THE EFFECTS
OF CLOUDS/PRECIP ON SUNDAY WILL LIMIT HIGHS TO THE 80S IN MANY AREAS
SUNDAY WITH POST FRONTAL HIGHS ON WEDNESDAY IN THE 80S AS WELL. AT
THIS POINT...THE HIGHEST HEAT INDICES THIS WEEK APPEAR WILL OCCUR ON
MONDAY WITH READINGS COMMONLY IN THE RANGE OF 100 TO 104 DEGREES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 602 AM CDT SAT JUL 20 2013
ISOLATED TO WIDELY SCATTERED THUNDERSTORMS WILL CONTINUE ACROSS
THE TAF SITES THROUGH 15Z. OTHERWISE...EXPECT VFR CONDITIONS FOR THE
LATE MORNING AND EARLY AFTERNOON. THERE WILL BE ANOTHER CHANCE FOR
SCATTERED THUNDERSTORMS LATE THIS AFTERNOON THROUGH THE MID
EVENING HOURS. LATE IN THE TAF PERIOD THERE COULD BE ANOTHER
CHANCE OF THUNDERSTORMS BUT DUE TO TIMING ISSUES I HAVE NOT
INCLUDED A VCTS GROUP FOR STORMS THAT MAY ARRIVE AROUND SUNRISE ON
SUNDAY.
GARGAN
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GARGAN
LONG TERM...63
AVIATION...GARGAN
AREA FORECAST DISCUSSION
NWS JACKSON KY
923 AM EDT SAT JUL 20 2013
.UPDATE...
ISSUED AT 923 AM EDT SAT JUL 20 2013
BAND OF ENHANCED CU IS PUSHING SOUTHEAST...EXTENDING FROM NEAR
DANVILLE TO WEST LIBERTY THIS MORNING. BASED ON INITIAL ANALYSIS THIS
MORNING...THIS MAY HELP TO GENERATE SOME ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS HEADING INTO THE AFTERNOON HOURS.
HOWEVER...THIS ACTIVITY WILL LIKELY SHIFT SOUTHEAST AS WE HEAD INTO
THE LATE AFTERNOON HOURS AS SUBSIDENCE AHEAD OF THE APPROACHING COLD
FRONT FROM THE NORTH OVERSPREADS THE AREA. LATEST HRRR TAKES MOST OF
THE DAY TO GET ANY PRECIPITATION AS FAR SOUTH AS FLEMING COUNTY
(LIKELY NOT UNTIL AFTER 22 OR 23Z). THUS...GOING TO BACK OFF ON THE
HIGHER PRECIPITATION CHANCES TODAY...BUT STILL CARRY SOME ISOLATED
COVERAGE ACROSS THE SOUTHEAST ASSOCIATED WITH THE BAND OF ENHANCED
CU AS IT DROPS SOUTHEAST. OTHERWISE...WILL GO WITH HIGHER POPS NORTH
OF I-64 AFTER 22Z. SOME QUESTION AS TO HOW MUCH ACTIVITY LINGERS INTO
TONIGHT AS THE FRONT WASHES OUT OVER THE AREA. WILL DROP POPS BACK
FOR THE OVERNIGHT HOURS AS COVERAGE WILL LIKELY REMAIN MORE ISOLATED
TO SCATTERED ALONG THE BOUNDARY SINCE IT WILL BE HARD TO SEE MUCH
ORGANIZED ACTIVITY ALONG THE STALLED BOUNDARY. UPDATE WILL BE OUR
SHORTLY.
UPDATE ISSUED AT 705 AM EDT SAT JUL 20 2013
INGESTED THE MOST CURRENT OBSERVATION DATA TO ESTABLISH NEW TRENDS IN
THE FORECAST GRIDS. THE FORECAST WAS ON TRACK OVERALL...ALTHOUGH THE
FOG THAT WAS FORECAST TO FORM OVERNIGHT WAS NOT NEARLY AS EXTENSIVE
AS ORIGINAL THINKING INDICATED. WITH THE FORECAST IN PRETTY GOOD
SHAPE OVERALL...NO UPDATE IS PLANNED AT THIS TIME.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 313 AM EDT SAT JUL 20 2013
MODELS IN PRETTY GOOD AGREEMENT WITH THE OVERALL LARGE SCALE
WEATHER PATTERN AND SENSIBLE WEATHER FOR THE NEXT COUPLE OF DAYS. A
WARM AND HUMID AIR MASS WILL REMAIN IN PLACE ACROSS EASTERN KENTUCKY
TODAY AND TOMORROW...AS SOUTHERLY FLOW PERSISTS AHEAD OF A SLOWLY
APPROACHING COLD FRONT. THE WEATHER TODAY SHOULD START OUT QUIET...AS
THE LACK OF A GOOD TRIGGER FOR CONVECTION SHOULD KEEP SHOWER AND
STORM ACTIVITY TO A MINIMUM THROUGH EARLY THIS AFTERNOON. SHOWERS AND
STORMS WILL GRADUALLY INCREASE IN COVERAGE BEGINNING MID AFTERNOON
TODAY...AS THE COLD FRONT FINALLY BEGINS MAKING ITS SOUTHWARD PUSH.
THE BEST CHANCE FOR RAIN WILL BEGIN EARLY THIS EVENING NORTH OF THE
MOUNTAIN PARKWAY. THE FRONT IS THEN PROGGED TO SAG SOUTHWARD OUT OF
THE OHIO VALLEY AND ACROSS CENTRAL AND EASTERN KENTUCKY OVERNIGHT
TONIGHT. ONCE LOSS OF DAYTIME HEATING BEGINS TO OCCUR...ANY SHOWERS
AND STORMS WILL DECREASE IN COVERAGE...WITH ONLY SCATTERED SHOWERS
AND ISOLATED STORMS EXPECTED DURING THE NIGHT TIME HOURS. ONCE THE
SUN HAS A BEEN UP FOR AWHILE ON SUNDAY...THE FRONT WILL BECOME ACTIVE
ONCE AGAIN...WITH NUMEROUS SHOWERS AND STORMS EXPECTED ACROSS THE
AREA FROM LATE SUNDAY MORNING THROUGH THE END OF THE DAY ON SUNDAY.
DUE TO SLUGGISH MIDDLE AND UPPER LEVEL WINDS...ANY SHOWERS AND STORMS
THAT FORM WILL BE VERY SLOW MOVING...WHICH COULD LEAD TO LOCALIZED
HEAVY RAIN AND POSSIBLY MINOR FLOODING ISSUES.
TEMPERATURES WILL BE QUITE HOT ONCE AGAIN TODAY...BUT WITH THE GROUND
STILL BEING SOMEWHAT MOIST FROM RECENT RAINFALL...AND WITH AREA
VEGETATION IN FULL LEAF...90 DEGREE READINGS WILL BE DIFFICULT TO
COME BY. WITH THAT IN MIND...LOWERED TODAYS HIGH TEMPERATURES ACROSS
THE BOARD TO REFLECT THIS. WILL LIKELY SEE READINGS TOP OUT MOSTLY IN
THE UPPER 80S AREA WIDE...WITH ISOLATED OCCURRENCES OF 90 HERE AND
THERE. HIGHS ON SUNDAY WILL LIKELY RUN SLIGHTLY BELOW NORMAL...DUE TO
SHOWER AND STORM ACTIVITY AND THE PASSAGE OF THE COLD FRONT. HIGHS ON
SUNDAY ARE EXPECTED TO TOP OUT IN THE LOWER 80S. OVERNIGHT LOWS WILL
BOTTOM OUT AROUND A BALMY 70 DEGREES. WINDS WILL REMAIN FAIRLY LIGHT
ACROSS THE AREA TODAY AND TOMORROW.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 313 AM EDT SAT JUL 20 2013
THE SYNOPTIC PATTERN OVER THE EASTERN U.S. NEXT WEEK WILL FEATURE
THE DEVELOPMENT OF AN UPPER LEVEL TROUGH EARLY IN THE WEEK WITH A
LEAD SHORTWAVE TRAVERSING THE OHIO VALLEY MONDAY AND MONDAY NIGHT.
OUR FORECAST WILL FEATURE THE HIGHEST RAIN CHANCES WITH THIS LEAD
SHORTWAVE ACTING AS THE FOCUS FOR SHOWERS AND THUNDERSTORMS MONDAY
AND MONDAY NIGHT. THIS FEATURE WILL PASS BY BUT THE UPPER LEVEL
TROUGH IS PROGGED TO HANG OUT WITH IT/S AXIS ALIGNED DOWN THE
APPALACHIAN CHAIN THROUGH AT LEAST FRIDAY...WITH SIGNS IN THE
MODELING THAT IT WILL GET REINFORCED NEXT WEEKEND. THIS SPELLS A
CONTINUATION OF UNSETTLED WEATHER WITH DAILY SHOWER AND THUNDERSTORM
CHANCES. A COLD FRONT WILL SLOWLY DROP THROUGH THE OHIO VALLEY
MIDWEEK RESULTING IN SCATTERED SHOWERS/STORMS...ESPECIALLY DURING
THE AFTERNOON AND EARLY EVENING HOURS. THE FRONT IS PROGGED TO DROP
TO OUR SOUTH FINALLY BY LATE THURSDAY INTO FRIDAY WITH A WEAK AREA
OF HIGH PRESSURE SLIDING DOWN INTO THE REGION. TRENDED RAIN CHANCES
DOWNWARD FROM INHERITED NUMBERS THURSDAY AND FRIDAY...BUT DID NOT
REMOVE THEM TOTALLY JUST YET.
THE GOOD NEWS IS THAT TEMPERATURES AND DEWPOINTS WILL BE ON A
DOWNWARD TREND DURING THE PERIOD. TEMPS WILL SETTLE BACK TO MORE
NORMAL VALUES FOR THIS TIME OF YEAR...WITH HIGHS GENERALLY IN THE
LOW TO MID 80S EACH DAY. DEWPOINTS WILL REMAIN HIGH...AROUND
70...UNTIL THE COLD FRONT DROPS TO OUR SOUTH LATE IN THE WEEK. THIS
SHOULD DROP DEWS BACK INTO THE 60S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 705 AM EDT SAT JUL 20 2013
FOG WAS NOT NEARLY AS WIDESPREAD AS THE EARLIER TAF INDICATED IT
WOULD BE...ESPECIALLY AT JKL AND SME. LOZ EXPERIENCE A FEW HOURS OF
FOG DURING THE PREDAWN HOURS THIS MORNING...WITH LIFR CONDITIONS FOR
A BRIEF PERIOD. AS FOR THE REST OF TODAY...SCATTERED SHOWERS AND
STORMS ARE EXPECTED TO BEGIN AFFECTING JKL AROUND 2Z TONIGHT...AND
LOZ AND SME AROUND 4Z...AS A COLD FRONT BEGINS TO MOVE SLOWLY
SOUTHWARD OUT OF THE OHIO VALLEY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...AR
LONG TERM...ABE
AVIATION...AR
AREA FORECAST DISCUSSION
NWS CARIBOU ME
630 AM EDT SAT JUL 20 2013
.SYNOPSIS...
A STRONG COLD FRONT WILL CROSS THE REGION LATE TODAY AND THIS EVENING.
A DRIER AND COOLER CANADIAN AIRMASS WILL THEN BUILD INTO THE AREA
ON SUNDAY AND HOLD OVER THE REGION THROUGH MONDAY. THE NEXT LOW
PRESSURE FROM THE GREAT LAKES WILL APPROACH THE REGION LATE MONDAY
NIGHT INTO TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
630 AM UPDATE...SATELLITE IMAGERY IS SHOWING MID CLOUDS ACROSS
MAINLY WESTERN PORTIONS OF THE FORECAST AREA THIS MORNING, WITH
SUNSHINE IN EASTERN MAINE. THESE CLOUDS WILL CONTINUE TO PUSH
EASTWARD THROUGH THIS MORNING. THERE`S NOT MUCH ON RADAR ATTM,
JUST SOME ISOLATED SHOWERS OVER THE SAINT JOHN VALLEY AND SOUTHERN
QUEBEC. ADDITIONAL SHOWERS WILL CONTINUE TO DEVELOP, THOUGH THE
BULK OF THE ACTIVITY SHOULD HOLD OFF UNTIL AT LEAST MID MORNING,
ESPECIALLY OVER NORTHERN MAINE. BOTH THE LATEST RUN AND HRRR MODEL
RUNS CONCUR WITH THIS THINKING. HAVE THEREFORE UPDATED THE
FORECAST TO REDUCE SKY COVER AND POPS OVER THE NEXT FEW HOURS.
OTHERWISE, THE PREVIOUS FORECAST LOOKS ON TRACK.
STRONG TO SEVERE STORMS ONCE AGAIN POSSIBLE TODAY, ESPECIALLY
ACROSS CENTRAL AND INTERIOR DOWNEAST MAINE. SPC HAS THESE AREAS IN
A SLIGHT RISK FOR SEVERE WEATHER THIS AFTERNOON AND EVENING.
A STRONG COLD FRONT CURRENTLY LIES ACROSS CENTRAL QUEBEC EARLY THIS
MORNING, STRETCHING SOUTHWESTWARD THROUGH THE GREAT LAKES. THIS
FEATURE WILL SLOWLY MOVE SOUTHWARD TODAY, CROSSING THE FORECAST AREA
THIS AFTERNOON AND EVENING. MOISTURE CONVERGENCE ALONG THIS FRONT
WILL SERVE AS A FOCUS FOR SHOWERS AND THUNDERSTORMS, ESPECIALLY THIS
AFTERNOON. THE BEST MOISTURE AND INSTABILITY WILL LIE SOUTH OF A
HOULTON-MILLINOCKET-GREENVILLE LINE; DEWPOINTS AROUND 70 AND SBCAPES
OF 1000+ J/KG WILL EXIST IN THIS REGION THIS AFTERNOON. THIS
INSTABILITY COMBINED WITH 0-6KM SHEAR AROUND 40 KT WILL ALLOW
THUNDERSTORMS TO BECOME STRONG TO SEVERE OVER CENTRAL AND INTERIOR
DOWNEAST AREAS, WITH DAMAGING WINDS THE MAIN THREAT. PWATS NEARING 2
INCHES AND FREEZING LEVELS AOA 14 KFT INDICATE THAT HEAVY RAIN WILL
BE POSSIBLE AS WELL.
ACROSS THE CROWN OF MAINE, SHOWERS AND THUNDERSTORMS WILL BE MORE
SCATTERED IN NATURE, WITH SOME LOCATIONS EVEN SEEING SOME SUNSHINE
FROM TIME TO TIME. THE EARLIER TIMING OF THE FRONTAL PASSAGE AND
SLIGHTLY LOWER MOISTURE CONTENT WILL LIMIT ANY SEVERE POTENTIAL.
THAT BEING SAID, GUSTY WINDS AND BRIEFLY HEAVY DOWNPOURS ARE STILL A
POSSIBILITY WITH ANY STRONGER STORMS.
RELIEF FROM THE PAST FEW DAYS` MUGGINESS FINALLY ARRIVES TONIGHT AS
COOL, DRY CANADIAN HIGH PRESSURE SETTLES OVER THE REGION BEHIND THE
FRONT. SHOWERS AND THUNDERSTORMS WILL QUICKLY COME TO AN END AS
DEWPOINTS DROP AND SKIES CLEAR OUT. LOWS WILL BE MUCH MORE
COMFORTABLE, ESPECIALLY IN NORTHERN MAINE WHERE TEMPERATURES WILL
DROP TO AROUND 50. CENTRAL AND DOWNEAST MAINE WILL STAY BIT WARMER,
GENERALLY IN THE UPPER 50S TO AROUND 60.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
SUN STILL LOOKS TO BE SIG COOLER AND MUCH DRIER AS CANADIAN AIR
ACCOMPANIED BY SFC DWPTS IN THE 40S MOVES INTO THE FA. THE SFC HI
THEN CRESTS OVR THE FA SUN NGT PROVIDING GOOD RADIATIONAL COOLING
WITH OVRNGT LOWS DROPPING TO ARND 40 DEG F FOR THE COOLEST NRN
VLYS WITH 40S ELSEWHERE AND ARND 50 ALG THE IMMEDIATE DOWNEAST
COAST.
MON SHOULD CONT FAIR WITH MSLY SUNNY SKIES...WITH LGT SW RETURN
FLOW WINDS ARND SFC HI PRES DEPARTING E THRU THE MARITIMES ALLOWING
A RECOVERY OF HI TEMPS AT LEAST 5 DEG WARMER THAN SUN AFTN...XCPT
DOWNEAST AREAS WHICH WILL BE HELD BACK A FEW DEG DUE TO AN AFTN
SEA BREEZE.
MON NGT WILL BEGIN FAIR...THEN INCREASING HI CLDNSS WILL MOVE SW
TO NE ACROSS THE FA LATE MON NGT AHEAD OF SFC LOW PRES SYSTEMS AND
AN ASSOCIATED S/WVS ADVCG ENE FROM THE GREAT LKS AND CNTRL CAN.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
FCSTS OF THE NAO TELECONNECTION PATTERN TRENDING TOWARD NEAR ZERO
AND THE PNA PATTERN TRENDING POSITIVE SHOULD KEEP 500 MB HTS LOWER
THRU THE LONG RANGE AS THE MEAN LW TROF HOLDS OVR E CNTRL CAN AND
THE ERN GREAT LKS. SUBSEQUENTLY HI TEMPS THIS PD WILL MSLY BE AT
TO BLO NORMAL. THE COOLEST DAY POTENTIALLY...WILL BE TUE DUE TO
LOWERING CLD CVR AND SHWRS MOVG INTO THE FA FROM THE WSW AS A SFC
LOW FROM THE GREAT LAKES MOVES TOWARD NW ME TUE NGT. FOR NOW...
WE SPLIT THE DIFFERENCE BETWEEN BLENDED MODEL AND MOS HI TEMPS
WITH MODELS INDICATING MUCH COOLER HI TEMPS TUE AFTN DUE TO RN`
COOLED AIR...JUST IN CASE FASTER MODELS SUCH AS THE GFS ARE TO
FAST IN BRINGING THICKER CLD CVR AND SHWRS INTO THE FA TUE.
USING THE CONSENSUS APCH...WE SHOW THE GREATEST POPS WITH THE
GREAT LKS/E CNTRL CAN S/WV SYSTEMS TO BE TUE NGT WHERE WE SHOW
UP TO LOW LIKELY POPS OVR PTNS OF DOWNEAST AND E CNTRL PTNS
OF THE FA. WITH SRLY WINDS WHICH DIMINISH WITHE THE APCH OF THE
SFC TROF AXIS BY ERLY WED MORN...WE MENTION PATCHY LATE NGT FOG
WITH SHWRS FOR LATE TUE NGT. WITH LITTLE OR NO SBCAPE SHOWN FOR
OUR FA WITH THIS SYSTEM TUE AFTN AND TUE NGT...WE DO NOT INDICATE
ANY THUNDER WITH SHWRS ATTM...BUT THIS CAN BE RE-EVALUATED IN
FUTURE FCST UPDATES IN CASE ELEVATED CNVCTN PLAYS A ROLE.
OTHERWISE...A SLOW MOVG COLD FRONT WILL CROSS THE FA FROM QB
PROV LATER WED INTO WED EVE AS THE UPPER TROF CROSSES THE REGION
BRINGING THE CHC OF ADDITIONAL SHWRS. CANNOT RULE OUT THUNDER...
BUT GIVEN THE RANGE OF TMG OF THE COLD FRONT CROSSING FOR WED...
WE WILL WILL HOLD OFF IN CALLING FOR THUNDER IN THE FCST GRIDS
ATTM FOR THIS PD. OTHERWISE...PRTL CLRG IS XPCTD WED NGT THRU
FRI...ALTHOUGH THE CONSENSUS OF MODEL SOLUTIONS STALL THE COLD
FRONT JUST E OF THE FA DURG THIS TM...RESULTING IN US KEEPING CHC
SHWRS POPS AND CLDNSS BANKED UP ALG THE SE PERIPHERY OF THE FA
DURG THESE PDS. FOR NOW...WE SHOW NEAR NORMAL HI AND LOW TEMPS
ACROSS THE FA TUE NGT THRU FRI...SUBJECT TO CHG OF COURSE DEPENDING
ON FUTURE MODEL TRENDS ON THE WX SYSTEMS XPCTD TO AFFECT THE FA
DURING THE LONG RANGE.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: OUTSIDE OF SOME LINGERING MVFR VISIBILITIES IN FOG AT
KBGR AND KBHB, VFR CONDITIONS WILL PREVAIL THIS MORNING BEFORE
GIVING WAY TO MVFR AS ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS
AFFECTS THE REGION. THE SOUTHERN TERMINALS WILL SEE THE STRONGEST
ACTIVITY, WITH HEAVY RAINFALL AND GUSTY WINDS POSSIBLE. IFR
CONDITIONS ARE POSSIBLE IN ANY THUNDERSTORMS. A COLD FRONT WILL
QUICKLY CROSS THE REGION TONIGHT, FOLLOWED BY MUCH DRIER AIR. AS
SUCH, PRECIPITATION WILL END AND SKIES CLEAR. CONDITIONS WILL
RETURN TO VFR AT ALL TERMINALS BY 06Z.
SHORT TO LONG TERM: VFR ALL SITES THRU MON NGT...THEN LOWERING TO
MVFR IN LOW CLDNSS AND SHWRS FROM SW TO NE BY TUE AFTN AND TO IFR
WITH SHWRS AND PATCHY FOG TUE NGT. CONDITIONS THEN SLOWLY IMPROVE
TO MVFR BY WED AFTN WITH LESSENING CVRG OF SHWRS.
&&
.MARINE...
NEAR TERM: SOUTHWEST WINDS 15-20 KT AND SOUTH SWELL OF 4 TO 6
FEET WILL CONTINUE THROUGH TODAY AHEAD OF A COLD FRONT MOVING
SOUTH OUT OF QUEBEC. THIS FRONT WILL CROSS THE WATERS THIS
EVENING, TURNING WINDS TO THE NW AND ALLOWING SEAS TO SUBSIDE.
THEREFORE, THE SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS REMAINS IN
PLACE THROUGH THIS EVENING.
SHORT TO LONG TERM: NO HDLNS NEEDED UNTIL TUE NGT INTO WED...WHEN
AN SCA FOR HAZ SEAS MAY BE NEEDED FOR OUR OUTER MZS DUE TO A SRLY
WIND FETCH AHEAD OF LOW PRES MOVG NE THRU ERN QB. WENT BLO A BLEND
OF WW3 AND SWAN NAM BY USING THE SMOOTHING FUNCTION ADJACENT TO
LAND...WHICH LOWERED WV HTS MOST OVR THE INNER BAY/HARBOR MZ.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 8 PM EDT THIS
EVENING FOR ANZ050-051.
&&
$$
NEAR TERM...HASTINGS
SHORT TERM...VJN
LONG TERM...VJN
AVIATION...HASTINGS/VJN
MARINE...HASTINGS/VJN
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
932 AM CDT Sat Jul 20 2013
.UPDATE...
Issued at 931 AM CDT SAT JUL 20 2013
Scattered convection has developed this morning along a lingering
frontal boundary surface boundary near US 50, with additional storms
further north near an elevated boundary near 850 hPa. Winds aloft are
quite weak, so this activity will be pulse in nature and slow to
drift eastward. Latest RAP and NAM suggest that this boundary, both
at the surface and aloft, may maintain its definition and nudge
northward slightly through the afternoon. This may keep rain chances
going into the afternoon for areas near and south of the Missouri
River. Trying to pinpoint location and timing of this activity is
quite difficult, so the forecast was adjusted to account for the
current location of showers and storms, blending into broader low-
chance PoPs through the afternoon.
&&
.SHORT TERM...(Today through Sunday)
Issued at 316 AM CDT SAT JUL 20 2013
The main forecast challenge for today will be precipitation chances
along a weak frontal boundary and pre-frontal trough stretching over
the forecast area. Convection-allowing models are hinting at the
possibility for re-development along the pre-frontal trough between
daybreak and mid-morning; however, this could occur on the southern
edge or even further south of the CWA, and should be fairly isolated
in nature. With the main boundary stalling south of I-70 today, the
main question will be whether afternoon storm development will occur
along the front. With only weak low-level convergence and a stout
capping inversion, afternoon convection still looks fairly unlikely.
The further south the surface boundary can sag this afternoon, the
better the chances will be for precipitation, since this would keep
the front a bit further from the midlevel thermal axis and should
result in a weaker cap... so have kept the higher PoPs confined to
areas south of I-70 for the late afternoon and early evening hours.
After this boundary becomes a bit more diffuse and continues to
filter southward out of the CWA, the main chances for precipitation
will come with a shortwave trough dropping southeast out of central
SD. Convection will develop during the afternoon or evening hours in
central SD and into eastern Nebraska, and will push southeast while
continuing to develop across the forecast area late tonight and into
Sunday. The severe weather potential still looks low with weak low-
level shear, moderate instability but lackluster lift, and
unimpressive downdraft CAPE. Although PWATs are fairly high and the
chance for measurable precipitation looks the highest in quite a
while for Sunday, have kept precipitation totals less than an inch
through the period due to a decent southeastward progression of the
wave and disintegration of the surface boundary.
Temperatures today will be held down slightly by scattered cloud
cover and weak mixing, but should still reach the lower 90s on both
sides of the frontal boundary. Widespread cloud cover and scattered
precipitation will keep temperatures cooler on Sunday, and should
hold highs mainly in the 80s across the region.
.LONG TERM...(Monday through Friday)
Issued at 316 AM CDT SAT JUL 20 2013
Previous forecast philosophy remains on track with regards to
extended forecast as operational models continue to show good
agreement with the general upper pattern. Persistent northwest flow
aloft is expected through much of the work week, with a general
flattening of the upper trough by the end of the week. This pattern
will result in continued chances for precipitation and temperatures
near or slightly below seasonal levels. Several upper disturbances
are projected to move through the region, and with a surface frontal
boundary residing in close proximity to the forecast area,
sufficient conditions will help promote the development of scattered
thunderstorms. The exact evolution, coverage, timing, and rainfall
amounts from convective episodes are still somewhat ill-resolved
with this period still several days away and the dependency of
subsequent days of convection and its effect on surface feature
positions. Beyond the inherent uncertainty with this type of setup,
confidence continues to increase that much of the forecast area will
see the potential for multiple rounds of precipitation through the
upcoming workweek. Maximum temperatures will progressively cool,
with highs in the 80s in most locations by midweek.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday Morning)
Issued at 637 AM CDT SAT JUL 20 2013
A few showers and thunderstorms will impact portions of west central
Missouri and eastern Kansas this morning, but should diminish over
the next several hours and remain south of all TAF sites. Otherwise,
mainly VFR conditions are expected today with a possibility for
additional storm development in central KS/MO this afternoon, and a
high probability of widespread storms around 12z Sunday morning. A
frontal boundary will also stall around or south of I-70 today, which
will keep winds generally light but variable in direction.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
UPDATE...Hawblitzel
SHORT TERM...Laflin
LONG TERM...Blair
AVIATION...Laflin
AREA FORECAST DISCUSSION
NWS HASTINGS NE
944 AM CDT SAT JUL 20 2013
.UPDATE...
ISSUED AT 944 AM CDT SAT JUL 20 2013
AS EXPECTED MULTIPLE TSTM CLUSTERS DEVELOPED LAST NGT OVER SD AND
ARE CURRENTLY ON-GOING ALONG THE SD-NEB BORDER. A SWD MOVING
OUTFLOW BOUNDARY AS EMINATED FROM THESE CLUSTERS AND IS
APPROACHING I-80 PER VIS SATELLITE ANIMATION. THIS WILL INCREASE
THE SHEAR AS SFC WINDS ARE NE BEHIND THIS BOUNDARY. AM STILL
EVALUATING TSTM POTENTIAL FOR LATER TODAY BUT THE INITIAL LOOK AT
THE LBF/OAX 12Z SOUNDINGS DOES NOT LOOK GOOD. WILL HAVE MORE LATER
ON THIS.
OTHERWISE...SOME SHORT-TERM ENHANCEMENTS HAVE BEEN MADE TO CLOUDS/
WX/POPS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM CDT SAT JUL 20 2013
WE ARE LOOKING AT ONE OF OUR BETTER CHANCES OF SHOWERS AND
THUNDERSTORMS THIS EVENING INTO TONIGHT.
THIS IS A DIFFICULT FORECAST WHEN IT COMES TO THE CHANCE OF
PRECIPITATION. WE HAVE BEEN DRY ACROSS THE FORECAST AREA EARLY THIS
MORNING. HOWEVER...A FEW FORECAST MODELS LIKE THE HRRR ATTEMPT TO
DEVELOP SHOWERS AND THUNDERSTORMS ALONG OLD OUTFLOW BOUNDARIES A
LITTLE LATER THIS MORNING. OVERALL FORCING IS WEAK THIS MORNING AND
WILL ONLY CALL FOR LOW END SLIGHT POPS THROUGH NOON ACROSS NORTH
CENTRAL KANSAS AND FOR AREAS PRIMARILY ALONG AND WEST OF HIGHWAY
281. THUNDERSTORMS ARE MOST LIKELY TO DEVELOP OVER THE NEBRASKA
SANDHILLS INTO SW SOUTH DAKOTA DURING THE MID TO LATE AFTERNOON
HOURS ALONG A SOUTHEASTWARD MOVING SFC TROUGH OF LOW PRESSURE.
SEVERAL FORECAST MODELS SUCH AS THE 06Z NAM AND 00Z GFS CONGEAL
CONVECTION THIS EVENING INTO A LARGE RAIN MAKING CLUSTER CALLED
AN MCS OR MESOSCALE CONVECTIVE SYSTEM THAT WOULD TRACK ACROSS OUR
FORECAST AREA. CONSEQUENTLY...WILL CONTINUE TO CARRY THE LIKELY
POPS FOR THIS EVENING. DEEP LAYER WIND SHEAR VALUES WILL GENERALLY
RANGE FROM 30 TO 35 KTS AND MLCAPE WILL BE MODEST...REACHING UP
CLOSE TO 2000 J/KG. THEREFORE...THE ENVIRONMENT WILL SUPPORT THE
POSSIBILITY OF SEVERE THUNDERSTORMS WITH THE PRIMARY FOCUS BEING
DURING THE EVENING HOURS. THIS IS PRIMARILY A WIND AND HAIL THREAT
WITH NOT MUCH OF A TORNADO THREAT GIVEN THE SHEAR IS WEAK IN THE
LOWEST ATMOSPHERIC LAYERS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 408 AM CDT SAT JUL 20 2013
MAIN FORECAST CONCERNS WILL BE THE CHANCES FOR THUNDERSTORMS AND
TEMPERATURES.
MODELS ARE SIMILAR IN THE MAIN FEATURES DURING THIS PERIOD WITH
NORTHWEST FLOW ACROSS THE AREA AND SEVERAL UPPER LEVEL WAVES MOVE
THROUGH THE REGION. EACH OF THEM HAVE THE POTENTIAL TO BRING A
CHANCE FOR THUNDERSTORMS TO THE AREA. THE MAIN DIFFERENCES IN THE
MODELS IS THAT THE TIMING OF THE INDIVIDUAL WAVES HAS SOME
DIFFERENCES AND HOW STRONG THEY ARE. IT DEFINITELY WILL NOT RAIN
EVERY DAY OR AT EVERY LOCATION...BUT THERE IS MAINLY SMALL CHANCES
NEARLY EVERY DAY.
THE PRECIPITATION FROM SATURDAY NIGHT WILL MOVE OUT OF THE AREA
SUNDAY MORNING BUT ANOTHER WAVE WILL MOVE INTO THE AREA SUNDAY
AFTERNOON AND EVENING AND BRING ANOTHER CHANCE FOR THUNDERSTORMS.
THE THUNDERSTORMS SHOULD BE NEARLY OUT OF THE AREA DURING THE
OVERNIGHT HOURS SUNDAY NIGHT. MONDAY MORNING WILL ALSO CONTINUE DRY
BEFORE THE NEXT WAVE MOVES INTO THE AREA MONDAY AFTERNOON AND MONDAY
NIGHT. ANOTHER WAVE MOVES IN TUESDAY AND TUESDAY NIGHT. THIS IS A
FAIRLY STRONG WAVE AND CHANCES ARE A LITTLE BETTER FOR SOME
PRECIPITATION...WITH A SURFACE LOW AND WEAK COLD FRONT THAT MOVE
THROUGH THE AREA.
ONCE THE PRECIPITATION MOVES OUT TUESDAY NIGHT...WEDNESDAY AND
WEDNESDAY NIGHT LOOK TO BE DRY WITH A BREAK IN THE SERIES OF UPPER
LEVEL WAVES. BEHIND THE COLD FRONT THERE IS A COOLER SURFACE HIGH
AND TEMPERATURES WILL BE CLOSER TO NORMAL FOR THIS TIME OF YEAR.
THURSDAY THROUGH FRIDAY THERE IS ANOTHER UPPER LEVEL WAVE THAT MOVES
THROUGH THE AREA. THIS ONE IS A LITTLE STRONGER THAN SOME OF THE
OTHERS. THERE IS ANOTHER SURFACE LOW AND COLD FRONT THAT MOVES
THROUGH AND THE CHANCES FOR THUNDERSTORMS RETURN TO THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 529 AM CDT SAT JUL 20 2013
THE WIND WILL REMAIN LIGHT AND AT TIMES VARIABLE THIS MORNING
ALTHOUGH BECOMING MORE SOUTHEASTERLY WITH TIME. THE WIND WILL
THEN INCREASE BY EARLY AFTERNOON THANKS TO DIURNAL HEATING AND
SUBSEQUENTLY DIE DOWN BY EARLY EVENING ONCE WE LOSE THE AFTERNOON
HEATING. WE HAVE AN INCREASING CHANCE OF THUNDERSTORMS AS WE HEAD
THROUGH THE AFTERNOON AND ESPECIALLY BY EVENING. THE WIND
WILL LIKELY BECOME VARIABLE AND RATHER GUSTY IN AND AROUND
ANY THUNDERSTORMS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...WESELY
LONG TERM...JCB
AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
552 AM CDT SAT JUL 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM CDT SAT JUL 20 2013
WE ARE LOOKING AT ONE OF OUR BETTER CHANCES OF SHOWERS AND
THUNDERSTORMS THIS EVENING INTO TONIGHT.
THIS IS A DIFFICULT FORECAST WHEN IT COMES TO THE CHANCE OF
PRECIPITATION. WE HAVE BEEN DRY ACROSS THE FORECAST AREA EARLY THIS
MORNING. HOWEVER...A FEW FORECAST MODELS LIKE THE HRRR ATTEMPT TO
DEVELOP SHOWERS AND THUNDERSTORMS ALONG OLD OUTFLOW BOUNDARIES A
LITTLE LATER THIS MORNING. OVERALL FORCING IS WEAK THIS MORNING AND
WILL ONLY CALL FOR LOW END SLIGHT POPS THROUGH NOON ACROSS NORTH
CENTRAL KANSAS AND FOR AREAS PRIMARILY ALONG AND WEST OF HIGHWAY
281. THUNDERSTORMS ARE MOST LIKELY TO DEVELOP OVER THE NEBRASKA
SANDHILLS INTO SW SOUTH DAKOTA DURING THE MID TO LATE AFTERNOON
HOURS ALONG A SOUTHEASTWARD MOVING SFC TROUGH OF LOW PRESSURE.
SEVERAL FORECAST MODELS SUCH AS THE 06Z NAM AND 00Z GFS CONGEAL
CONVECTION THIS EVENING INTO A LARGE RAIN MAKING CLUSTER CALLED
AN MCS OR MESOSCALE CONVECTIVE SYSTEM THAT WOULD TRACK ACROSS OUR
FORECAST AREA. CONSEQUENTLY...WILL CONTINUE TO CARRY THE LIKELY
POPS FOR THIS EVENING. DEEP LAYER WIND SHEAR VALUES WILL GENERALLY
RANGE FROM 30 TO 35 KTS AND MLCAPE WILL BE MODEST...REACHING UP
CLOSE TO 2000 J/KG. THEREFORE...THE ENVIRONMENT WILL SUPPORT THE
POSSIBILITY OF SEVERE THUNDERSTORMS WITH THE PRIMARY FOCUS BEING
DURING THE EVENING HOURS. THIS IS PRIMARILY A WIND AND HAIL THREAT
WITH NOT MUCH OF A TORNADO THREAT GIVEN THE SHEAR IS WEAK IN THE
LOWEST ATMOSPHERIC LAYERS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 408 AM CDT SAT JUL 20 2013
MAIN FORECAST CONCERNS WILL BE THE CHANCES FOR THUNDERSTORMS AND
TEMPERATURES.
MODELS ARE SIMILAR IN THE MAIN FEATURES DURING THIS PERIOD WITH
NORTHWEST FLOW ACROSS THE AREA AND SEVERAL UPPER LEVEL WAVES MOVE
THROUGH THE REGION. EACH OF THEM HAVE THE POTENTIAL TO BRING A
CHANCE FOR THUNDERSTORMS TO THE AREA. THE MAIN DIFFERENCES IN THE
MODELS IS THAT THE TIMING OF THE INDIVIDUAL WAVES HAS SOME
DIFFERENCES AND HOW STRONG THEY ARE. IT DEFINITELY WILL NOT RAIN
EVERY DAY OR AT EVERY LOCATION...BUT THERE IS MAINLY SMALL CHANCES
NEARLY EVERY DAY.
THE PRECIPITATION FROM SATURDAY NIGHT WILL MOVE OUT OF THE AREA
SUNDAY MORNING BUT ANOTHER WAVE WILL MOVE INTO THE AREA SUNDAY
AFTERNOON AND EVENING AND BRING ANOTHER CHANCE FOR THUNDERSTORMS.
THE THUNDERSTORMS SHOULD BE NEARLY OUT OF THE AREA DURING THE
OVERNIGHT HOURS SUNDAY NIGHT. MONDAY MORNING WILL ALSO CONTINUE DRY
BEFORE THE NEXT WAVE MOVES INTO THE AREA MONDAY AFTERNOON AND MONDAY
NIGHT. ANOTHER WAVE MOVES IN TUESDAY AND TUESDAY NIGHT. THIS IS A
FAIRLY STRONG WAVE AND CHANCES ARE A LITTLE BETTER FOR SOME
PRECIPITATION...WITH A SURFACE LOW AND WEAK COLD FRONT THAT MOVE
THROUGH THE AREA.
ONCE THE PRECIPITATION MOVES OUT TUESDAY NIGHT...WEDNESDAY AND
WEDNESDAY NIGHT LOOK TO BE DRY WITH A BREAK IN THE SERIES OF UPPER
LEVEL WAVES. BEHIND THE COLD FRONT THERE IS A COOLER SURFACE HIGH
AND TEMPERATURES WILL BE CLOSER TO NORMAL FOR THIS TIME OF YEAR.
THURSDAY THROUGH FRIDAY THERE IS ANOTHER UPPER LEVEL WAVE THAT MOVES
THROUGH THE AREA. THIS ONE IS A LITTLE STRONGER THAN SOME OF THE
OTHERS. THERE IS ANOTHER SURFACE LOW AND COLD FRONT THAT MOVES
THROUGH AND THE CHANCES FOR THUNDERSTORMS RETURN TO THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 529 AM CDT SAT JUL 20 2013
THE WIND WILL REMAIN LIGHT AND AT TIMES VARIABLE THIS MORNING
ALTHOUGH BECOMING MORE SOUTHEASTERLY WITH TIME. THE WIND WILL
THEN INCREASE BY EARLY AFTERNOON THANKS TO DIURNAL HEATING AND
SUBSEQUENTLY DIE DOWN BY EARLY EVENING ONCE WE LOSE THE AFTERNOON
HEATING. WE HAVE AN INCREASING CHANCE OF THUNDERSTORMS AS WE HEAD
THROUGH THE AFTERNOON AND ESPECIALLY BY EVENING. THE WIND
WILL LIKELY BECOME VARIABLE AND RATHER GUSTY IN AND AROUND
ANY THUNDERSTORMS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...WESELY
LONG TERM...JCB
AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1055 AM EDT SAT JUL 20 2013
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL EXTEND INTO THE AREA THROUGH TODAY. AN
UPPER LEVEL TROUGH WILL SLOWLY AMPLIFY OVER THE REGION SUNDAY
THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1055 AM SATURDAY...
CLOUDS WERE HANGING IN ACROSS MUCH OF CENTRAL NORTH CAROLINA THIS
MORNING. THESE CLOUDS SHOULD GRADUALLY MIX DURING THE LATE MORNING...
AND ALREADY THERE WERE MORE THIN SPOTS AND BREAKS OVER THE WESTERN
PIEDMONT ON THE VISIBLE SATELLITE IMAGES. BUFR SOUNDINGS AND
LOW-LEVEL MOISTURE FIELDS WOULD SUGGEST MIXING SHOULD TAKE PLACE AS
WELL TO A PARTLY SUNNY SKY ON AVERAGE...LIKELY MORE MOSTLY SUNNY FOR
A WHILE MAINLY OVER PARTS OF THE SOUTHERN COASTAL PLAIN. FOR THE
REST OF THE DAY INTO THIS EVENING...A SURFACE TROUGH WILL REMAIN
NEAR THE EDGE OF THE FOOTHILLS AND THE PIEDMONT...WITH AN 850MB
TROUGH ESSENTIALLY IN THE SAME LOCATION. 0-6KM SHEAR IS WEAK...TO
AROUND 10KT AT BEST...AND WITH A SLIGHTLY STEEPER LAPSE RATE ABOVE
THE INVERSION NOTED ON THE KGSO AND KRNK SOUNDINGS COMPARED TO
KMHX...OVERALL INSTABILITY SHOULD BE GREATER OVER THE NORTHWEST
PIEDMONT DURING THE LATE AFTERNOON. A SMALL CLUSTER OF SHOWERS AND
THUNDERSTORMS WAS LOCATED OVER THE FAR NORTHWEST PART OF THE STATE
EARLY THIS MORNING...AND ANY ASSOCIATED MID-LEVEL VORTICITY WITH
THAT CLUSTER COULD HELP...ALONG WITH THE SURFACE AND 850MB TROUGHS
AND BETTER INSTABILITY...TO GENERATE SCATTERED THUNDERSTORMS
PARTICULARLY IN VICINITY OF THE INTERSTATE 85 CORRIDOR DURING THE
AFTERNOON INTO THE EARLY EVENING. THE LATEST SPC MESOANALYSIS SHOWS
A RELATIVE MAXIMUM OF DOWNDRAFT CAPE OVER CENTRAL NORTH CAROLINA...
TO NEAR 800J/KG...THOUGH SHEAR AND 1000-500MB LAPSE RATES ARE
WEAK...AND WINDS ALOFT SHOULD LIGHTEN SOME...TO VALUES AT 925MB ONLY
NEAR 10 TO 20KT BY 18Z. THE SPC DAY ONE HAS A FIVE PERCENT LINE FOR
SEVERE STORMS FOR WIND MAINLY FROM THE TRIANGLE NORTH...AND IT IS IN
THIS AREA...MAINLY AGAIN ALONG AND NORTH OF INTERSTATE 85...WHERE
HIGHER THETA-E AIR IN COMBINATION WITH SLIGHTLY BETTER LAPSE RATES
COMPARED TO THE REST OF CENTRAL NORTH CAROLINA COULD RESULT IN A
STORM WITH A WIND GUST AROUND 50 MPH. OVER THE FAR EAST AND
SOUTHEAST...SUCH AS EAST OF I-95...THE LATEST RUC SHOWS LIMITED
INSTABILITY AND GREATER MID-LEVEL RIDGING SUCH THAT THE POTENTIAL
FOR SHOWERS AND THUNDERSTORMS SHOULD BE LESSER THERE. ANY SHOWERS
AND THUNDERSTORMS SHOULD TEND TO DIMINISH DIURNALLY. 1000-850MB
THICKNESSES ARE SLIGHTLY REDUCED FROM THOSE FORECAST FRIDAY...AND
WITH THE CLOUDS TO START PULLED BACK A DEGREE OR TWO THE HIGHS IN
THE TRIAD. OVERNIGHT LOWS IN THE LOWER TO MID 70S.
&&
.SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
AS OF 245 AM SATURDAY...
SHORTWAVE ENERGY EMBEDDED IN THE MAIN BELT OF WESTERLIES ALONG THE
US-CANADA BORDER WILL CONTINUE TRACK EAST ACROSS THE NORTHEAST AND
NORTHERN MID-ATLANTIC STATES ON SUNDAY. IT IS BECOMING INCREASINGLY
MORE APPARENT...THAT THE SURFACE FRONTAL ZONE WILL STALL NORTH OF
THE AREA...EXTENDING FROM THE SOUTHERN OHIO VALLEY AND JUST SOUTH OF
THE NATIONS CAPITAL. WITH THE APPRECIABLE FORCING/LIFT REMAINING
NORTH OF THE AREA...LOOKS LIKE CONVECTION WILL STILL HAVE MAINLY A
DIURNAL MODE...INITIALLY FIRING ALONG THE PIEDMONT TROUGH AND
DIFFERENTIAL HEATING OF THE HIGHER TERRAIN ALONG THE MTNS/FTHLS AND
SEABREEZE INTERACTION IN THE EAST. WITH INCREASING PWATS TO OR ABOVE
2.0"...COVERAGE SHOULD BE GREATER THAN THE PAST FEW DAYS...WITH
HIGHEST PROBABILITIES IN THE WEST. AN ISOLATED STRONG TO SEVERE
STORM CANNOT BE RULED OUT GIVEN THE MODERATE TO STRONG
INSTABILITY...BUT WEAK FLOW ALOFT SHOULD LIMIT A MORE ORGANIZED
SEVERE THREAT. ADDITIONALLY...ANY SLOW MOVING OR TRAINING STORMS
COULD RESULT IN LOCALIZED FLOODING.
HIGHS IN THE UPPER 80S TO LOWER 90S. LOWS IN THE LOWER 70S.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 245 AM SATURDAY...
MONDAY AND MONDAY NIGHT:
A BACKDOOR COLD FRONT IS EXPECTED TO STALL OVER VA ON MONDAY WITH
THE H85 TROUGH AXIS EXTENDING EAST THROUGH CENTRAL NC AND THE MAIN
UPPER LEVEL TROUGH OVER THE APPALACHIANS. THE ATMOSPHERE WILL BE
SUFFICIENTLY MOIST AND UNSTABLE TO ALLOW CONVECTION TO DEVELOP
DURING THE AFTERNOON AS WEAK UPPER LEVEL DISTURBANCES MOVE OVER THE
AREA. AHEAD OF THE MAIN TROUGH...THE 00Z GFS SHOWS A H3 SHORTWAVE
DISTURBANCE MOVING NORTHEAST FROM THE LOW OVER LOUISIANA AROUND THE
BASE OF THE TROUGH AND OVER NC MONDAY EVE/NIGHT. DEPENDING ON THE
TIMING...THIS FEATURE COULD ENHANCE CONVECTION LATE MONDAY...OR HELP
SUSTAIN CONVECTION INTO THE OVERNIGHT HOURS. GIVEN THE
UNCERTAINTY...WILL KEEP HIGHEST PRECIP CHANCES DURING THE AFT/EVE
HOURS AND ONLY INCREASE THEM SLIGHTLY DURING THE 03Z-07Z TIMEFRAME.
HIGHS MONDAY STILL EXPECTED TO BE IN THE MID TO UPPER 80S...WITH
OVERNIGHT LOWS MAINLY IN THE LOW TO MID 70S.
TUESDAY THROUGH FRIDAY:
THE UPPER LEVEL TROUGH AXIS SHOULD SHIFT EAST OVER CENTRAL NC ON
TUESDAY WHERE IT WILL LINGER THROUGH FRIDAY. AS THE H85 TROUGH
SLOWLY DRIFTS EAST ON TUESDAY...WINDS OVER THE WESTERN PORTIONS OF
THE AREA MAY SHIFT FROM SOUTHWEST TO MORE WESTERLY. THIS WOULD HELP
DRY OUT THE MID LEVELS A BIT LATE TUESDAY THROUGH WEDNESDAY...THUS
DECREASING PW VALUES SOME. MEANWHILE...THERE IS A DESCENT CHANCE THE
EAST WILL REMAIN UNDER SW FLOW...WITH BETTER MOISTURE ADVECTION AND
GREATER INSTABILITY. MID AND UPPER LEVEL DISTURBANCES MOVING OVER NC
DURING THIS PERIOD WILL LIKELY HELP GENERATE DIURNALLY DRIVEN
CONVECTION. ALTHOUGH GENERALLY CHANCES MAY BE SOMEWHAT BETTER IN THE
EAST...CONFIDENCE WITH REGARD TO LOCATION AND COVERAGE OF THE
CONVECTION REMAINS LOW AT THIS TIME...THUS WILL CARRY CHANCE POPS
DURING THE AFT/EVE ACROSS THE ENTIRE AREA THROUGH THE PERIOD. WILL
CONTINUE THE PERSISTENCE TEMP FORECAST...WITH HIGHS IN THE MID TO
UPPER 80S AND LOWS IN THE LOW TO MID 70S.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
AS OF 1055 AM SATURDAY...
24-HR TAF PERIOD:
MVFR STRATUS WILL SLOWLY LIFT DURING THE REST OF THE MORNING.
ISOLATED-TO-SCATTERED SHOWERS AND THUNDERSTORMS SHOULD OCCUR THIS
AFTERNOON AND EVENING...WITH THE HIGHEST PROBABILITIES IN VICINITY
OF INTERSTATE 85.
LOOKING AHEAD:
AN UPPER LEVEL TROUGH WILL GRADUALLY AMPLIFY OVER THE REGION
SUNDAY THROUGH EARLY NEXT WEEK. THIS WILL RESULT IN AN ABOVE NORMAL
COVERAGE AND CHANCES FOR SHOWERS/THUNDERSTORMS DURING THE AFTERNOON
AND EVENING HOURS SUNDAY THROUGH WEDNESDAY. A POTENTIAL FOR SUB-VFR
FOG/STRATUS WILL ALSO PERSIST DURING THE EARLY MORNING HOURS...
PRIMARILY IN THE 06-11Z TIME FRAME.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CBL/DJF
NEAR TERM...CBL/DJF
SHORT TERM...CBL
LONG TERM...KC
AVIATION...CBL/DJF
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
915 AM EDT SAT JUL 20 2013
.SYNOPSIS...
A HEAT WAVE-ENDING COLD FRONT MOVES THOUGH LATE TODAY...
A MID-TROPOSPHERIC TROUGH WILL PUSH COOLER DRIER AIR INTO THE
REGION OVER THE NEXT 24 HOURS. IT WILL ALSO TRIGGER SOME STRONG
THUNDERSTORMS. A SECOND TROUGH AND ATTENDANT COLD FRONT COULD
TRIGGER SHOWERS TOWARD MID-WEEK. OVERALL...AN UPPER LEVEL TROUGH
WILL DOMINATE OUR AREA. THUS MOST OF NEXT WEEK WILL FEEL
RELATIVELY COOL TO OUR RECENT HEAT WAVE.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
13Z...EARLIER WIDESPREAD RAIN SHIELD TO THE NORTH HAS DISSIPATED.
ONLY REMAINING SHOWERS ARE IN THE SW/SC MTS...BUT TAME AT THIS
TIME. RUC HANDLING THE CURRENT COVERAGE OF THE SHOWERS WELL...AND
OUTPUT HAS BEEN USED AS BASIS FOR REST OF THE POP GRIDS FOR TODAY.
SEVERE STORMS STILL POSSIBLE...BUT WE WILL HAVE TO GET RID OF THE
HIGHER CLOUDS. THIS SHOULD NOT BE A PROBLEM...AND BLYR MOISTURE IS
GOING TO BE HIGH. DEWPOINTS ACTUALLY REMAIN HIGHER IN THE AREAS
WHICH WERE DRY OVERNIGHT.
REST AS FOLLOWS FROM PREV DISCS...
0820Z UPDATE...THE SERIES OF CONVECTIVE LINES
AND THE MCS ACTIVITY TO OUR WEST TRIGGERED SOME SHOWERS IN WARREN
COUNTY. THE LATEST ROUND OF INTENSE CONVECTION IS NOW IN NORTHERN
OHIO. MOST HIGH RESOLUTION MODELS HAVE DIFFICULTY BRINGING THIS
CONVECTION INTO OUR REGION WITH MUCH VIGOR. SHOWERS AND
THUNDERSTORMS ARE LIKELY IN NORTHWESTERN AREAS THIS MORNING.
THESE SEEM HIGH RESOLUTION MODELS IMPLY A BETTER CHANCE OF STRONG
STORMS IN BOTH SOUTHWEST AND CENTRAL AREAS...GENERALLY AFTER ABOUT
2 PM TODAY. THE NCEP MODEL SUITE AND ENSEMBLES IMPLY A STRONG LOW-
LEVEL JET...SOME GOOD CAPE OVER 1500JKG-1 AND STRONG SOUTHWESTERLY
FLOW. THUS SOME MULTI-CELLULAR LINES COULD DEVELOP AND THIS WOULD
LIKELY PRODUCE SOME POTENTIAL SEVERE STORMS LATER THIS AFTERNOON.
MORE MODESTLY...OVERNIGHT TEMPERATURES ARE IN THE 70S NEARLY
EVERYWHERE...EVEN IN THE NORTHWEST DUE TO CLOUDS AND ENHANCED
SOUTHWESTERLY FLOW AHEAD OF THE COLD FRONT TO OUR NORTHWEST. DEW
POINTS ARE IN THE 60S TO NEAR 70 IN THE EXTREME SOUTHEAST. THE
TEMPERATURE AND HUMIDITY VALUES KEEP ALL PUT A FEW ISOLATED POINT
APPARENT TEMPS BELOW 100...NO HEAT PRODUCTS TODAY.
IT WILL STILL BE HOT IN EAST AS THE COLD FRONT WILL BE SLOWER TO
ARRIVE. BEST CHANCE PRECIPITATION WILL BE BEFORE 19Z IN NORTHWEST
AND AFTER ABOUT 20Z IN SOUTHERN AREAS.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM SUNDAY/...
THE COOLER AND DRIER AIR SHOULD TAKE HOLD OF THE NORTHERN TIER BY
EARLY EVENING AND THE CHANCE OF PRECIPITATION WILL BE LOW. MOST
CENTRAL AREAS TOO SHOULD BE NORTH OF THE MAIN AREA OF RAIN THREAT
WITHIN A FEW HOURS OF 6 PM. THE SREF AND OTHER MODELS IMPLY
LINGERING THREAT OF SHOWERS AND THUNDERSTORMS IN SOUTHERN AREAS
AND ESPECIALLY SOUTHEAST LINGERS TO ABOUT 8-10 PM.
THE WINDS BECOME WEST TO NORTHWEST OVER MOST OF THE REGION DURING
THE EVENING HOURS...THE HIGH PW AIR IS GENERALLY CONFINED TO THE
SOUTHEAST AFTER ABOUT 7 PM THIS EVENING AND BY ABOUT 8 AM SUNDAY
THE PW VALUES ARE NORMAL ACROSS OUR ENTIRE REGION. THE FRONT WILL
BE SLOW TO CLEAR THE SOUTH EASTERN MOST AREAS UNTIL EARLY SUNDAY
MORNING. HAD TO HOLD SOME POPS IN ALONG SOUTHERN AREAS INTO EARLY
SUNDAY.
BEST NEWS IS THE 20C ISOTHERM AT 850 HPA IS GONE BEFORE 5 PM
THIS EVENING AND WE KICK THE 18C ISOTHERM OUT BY ABOUT 7 PM. BETTER
YET...WE WELCOME THE 12C ISOTHERM INTO THE STATE ABOUT 7 AM SUNDAY
AND LET IT SAG SOUTH DURING THE DAY SUNDAY. IT SHOULD BE A
SPECTACULARLY COMFORTABLE DAY SUNDAY. WITH LOW PW VALUES AND
COOLER TEMPERATURES. HOPEFULLY ANY CONVECTION WILL BE CLOSE TO THE
FRONT SOUTH OF THE MASON-DIXON LINE.
WE CAN SAY GOOD BY TO THE HEAT WAVE OF MID JULY 2013.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
SUNDAY SHOULD BE A POST FRONTAL DAY WITH PW VALUES NEAR TO
SLIGHTLY BELOW NORMAL. THE LOWER TROPOSPHERIC TEMPERATURES WILL BE
NEAR NORMAL TOO. THE CHANCE FOR SHOWERS SHOULD BE LOW...WITH PERHAPS
THE HIGHEST CHANCE IN THE SOUTHERNMOST AREAS...CLOSE TO THE FRONTAL
BOUNDARY. OVERALL...SUNDAY IS LOOKING LIKE A VERY PLEASANT DAY FOR
MOST AREAS AS A WEAK AREA OF HIGH PRESSURE WILL BE OVER THE
REGION. THE LOWER HUMIDITY AND LOWER TEMPERATURES SHOULD BE
WELCOME RELIEF.
THE LOW-LEVEL FRONTAL BOUNDARY DOES NOT PUSH TOO FAR TO OUR
SOUTH. ANOTHER WAVE APPROACHES FROM THE WEST AND WILL LIKELY PULL
SOME OF THE MOISTURE BACK INTO THE REGION LATE MONDAY INTO
TUESDAY. THIS WILL INCREASE THE CHANCE OF SHOWERS AND
THUNDERSTORMS MONDAY NIGHT...WHICH MAY LINGER INTO TUESDAY.
NORTHWESTERLY FLOW WILL LIKELY PUSH A FRONT THROUGH THE REGION
AROUND MID-WEEK. THIS COULD INCREASE THE CHANCE OF SHOWERS AND
THUNDERSTORMS...MOST LIKELY ON WEDNESDAY. BEHIND THIS SECOND FRONT
THE PW VALUES DROP TO BELOW NORMAL...SHOULD BE VERY COMFORTABLE
THURSDAY AND FRIDAY BEHIND THIS FRONT SHOULD THESE FORECAST PROVE
CLOSE TO CORRECT.
OVERALL...THE MODELS AND ENSEMBLES ALL SHOW A TROUGH OVER THE
EASTERN USA MOST OF THE COMING WEEK IMPLYING COOLER AND RELATIVELY
DRIER WEATHER. BY MID-WEEK THE HEAT WAVE OF MID-JULY 2013 SHOULD
BE A FAINT MEMORY.
&&
.AVIATION /13Z SATURDAY THROUGH WEDNESDAY/...
A LINE OF CONVECTION CONTINUES TO MAKE ITS WAY THROUGH CENTRAL
PA. IFR CIGS AND VSBYS HAVE REACHED BFD...JST AND AOO. SHOWERS AND
THUNDERSTORMS WILL CONTINUE ALONG THE SOUTHERN HALF OF THE STATE
THROUGH MID MORNING. ANY SHOWERS AND THUNDERSTORMS SHOULD FALL
APART BY THEY REACH THE CENTRAL PART OF THE STATE AND SHOULD NOT
AFFECT MDT AND LNS. ANY STORMS SHOULD CONTINUE TILL 14Z...BEFORE
THEY FALL APART. EXPECT SHOWERS AND THUNDERSTORMS TO BE POSSIBLE THIS
AFTERNOON OUT AHEAD OF THE INCOMING COLD FRONT.
AS THE COLD FRONT CROSSES THE REGION LATE TODAY IT SHOULD TRIGGER
SCT STRONG TO POSSIBLY SEVERE STORMS. THE WIND SHIFT SHOULD OCCUR FROM
NW- SE BY SAT NIGHT. CLEARING SKIES WITH DRIER AIR SHOULD BUILD IN
BEHIND THE FRONT...LATE TONIGHT INTO SUNDAY MORNING.
OUTLOOK...
SUN...MVFR TO VFR. SHOWERS/ISOLD TSRA PSBL SOUTH.
MON...VFR.
TUE-WED...VFR WITH PM SHOWERS/THUNDERSTORMS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT/STEINBUGL
NEAR TERM...GRUMM/DANGELO
SHORT TERM...GRUMM
LONG TERM...GRUMM/CERU
AVIATION...LA CORTE/CERU
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
650 AM CDT SAT JUL 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 317 AM CDT SAT JUL 20 2013
CURRENTLY AS OF 08Z...
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED NORTHWEST FLOW
FROM SOUTHWEST CANADA INTO THE GREAT LAKES REGION WITH TROUGHING
CENTERED OVER SOUTHEAST CANADA. NUMEROUS SHORTWAVES WERE PRESENT
WITHIN THE NORTHWEST FLOW...MOST WEAK BUT A FEW WORTH KEYING IN ON.
THE FIRST WAS OVER CENTRAL WISCONSIN WHICH MANAGED TO CARRY SHOWERS
ALMOST INTO TAYLOR AND CLARK COUNTIES BEFORE THEY DISSIPATED. MID
CLOUDS WERE CROSSING TAYLOR/CLARK...THOUGH. A SECOND SHORTWAVE WAS
OVER CENTRAL MN PRODUCING SOME SHOWER ACTIVITY. THIS SHOWER ACTIVITY
TOO WAS DISSIPATING BEING AT THE DAYTIME MINIMUM IN INSTABILITY. THE
THIRD SHORTWAVE OF NOTE...CONVECTIVELY INDUCED AND STILL MAINTAINING
SOME SHOWERS AND THUNDERSTORMS...WAS BACK OVER CENTRAL SOUTH DAKOTA.
DEEP LAYER MOISTURE HAS DEFINITELY DRIED OUT WITH PRECIPITABLE WATER
VALUES FROM 00Z SOUNDINGS RANGING BETWEEN 0.75 AND 1 INCH FROM THE
DAKOTAS INTO THE FORECAST AREA. THIS DRIER AIR HAS KEPT THE FORECAST
AREA OUTSIDE OF THAT CENTRAL WI DRY AND MOSTLY CLEAR OVERNIGHT.
TEMPERATURES WERE MUCH COOLER THIS MORNING THANKS TO THE PASSAGE OF
THE COLD FRONT YESTERDAY...WITH READINGS MAINLY IN THE 60S. 925MB
TEMPS HAVE ALSO COOLED...DOWN TO 22C AT MPX AT 00Z.
SYNOPTIC OVERVIEW...
A NORTHWEST FLOW STAYS IN PLACE ALOFT THROUGH THE SHORT TERM PERIOD.
MUCH OF THE FOCUS IS ON CONVECTIVELY INDUCED SHORTWAVES DEVELOPING
AND RIDING THROUGH THE NORTHWEST FLOW.
TODAY...
ATTENTION IS ON THE SHORTWAVE AND CONVECTION ACROSS CENTRAL SOUTH
DAKOTA. THE 20.00Z NAM REMAINS FAIRLY CONSISTENT IN BRINGING THIS
SHORTWAVE INTO WESTERN PORTIONS OF THE FORECAST AREA THIS AFTERNOON.
CONVECTION CURRENTLY WITH IT MAY EITHER HOLD TOGETHER OR DEVELOP AS
MLCAPE VALUES CLIMB INTO THE 500-1500 J/KG RANGE WITH LITTLE IN THE
WAY OF CIN. ANOTHER POSSIBLE TRIGGER FOR CONVECTION LOOKS TO BE A
LOW PRESSURE TROUGH OVER NORTHERN WI WHICH MODELS DROP DOWN JUST
SOUTH OF I-90 BY 21Z. 0-2KM CONVERGENCE IS VERY WEAK ON THIS
TROUGH...THOUGH. 20.00Z GFS/ECMWF AGREE WITH THE NAM ON THE
POTENTIAL FOR CONVECTIVE ACTIVITY WITH HIGH RESOLUTION MODELS
TENDING TO SUGGEST ISOLATED/SCATTERED CONVECTION. FOLLOWED THE HIGH
RESOLUTION MODELS WITH 20-40 PERCENT CHANCES...HIGHEST WEST OF THE
MS RIVER. IT SHOULD BE NOTED THAT 0-6KM SHEAR IS 40-45 KT...SO IF A
VIGOROUS ENOUGH UPDRAFT CAN FORM...WE COULD SEE A SEVERE STORM.
925MB TEMPS TODAY FROM 20C NORTH TO 23C SOUTH COMBINED WITH SUN
THROUGH ABOUT MID AFTERNOON SUPPORT HIGHS FROM THE MID 70S TO MID
80S.
TONIGHT...
CONVECTION THAT IS AROUND LATE THIS AFTERNOON LOOKS LIKE IT COULD
DIMINISH DURING THE EVENING WITH LOSS OF HEATING. FOCUS THEN TURNS
BACK TO THE WEST WHERE ALL MODELS HAVE BEEN CONSISTENT IN DEVELOPING
A CONVECTIVE SYSTEM AND SHORTWAVE OVER CENTRAL SOUTH DAKOTA INTO
NEBRASKA DURING THE EVENING. AS THIS SHORTWAVE TRACKS SOUTHEAST INTO
IOWA AND KANSAS DURING THE OVERNIGHT HOURS...ALONG WITH THE NORMAL
NOCTURNAL INCREASE IN THE LOW LEVEL JET...850MB MOISTURE TRANSPORT
INCREASES DOWNSTREAM. IT APPEARS THE BIGGER FOCUS FOR PRECIPITATION
WILL END UP BEING ALONG I-70...AROUND THE SAME SPOT WHERE THE COLD
FRONT THAT WENT THROUGH THE AREA YESTERDAY ENDS UP STALLING OUT AT.
HOWEVER...THE 20.00Z NAM/GFS/ECMWF SUGGEST THERE STILL MAY BE ENOUGH
850MB MOISTURE TRANSPORT FORCING FARTHER NORTH TO PRODUCE SOME
SHOWER/STORM ACTIVITY OVER THE FORECAST AREA. ON THE OTHER
HAND...THE 20.00Z REGIONAL CANADIAN KEEPS ANY OF THIS 850MB MOISTURE
TRANSPORT ACTIVITY WELL WEST OF THE AREA BEFORE 12Z SUNDAY. SINCE
THIS REGIONAL CANADIAN SCENARIO IS DEFINITELY PLAUSIBLE...AND HAVING
THE CONCERN FOR CONVECTION TO THE SOUTH...HAVE KEPT CHANCES OF
PRECIPITATION IN THE 20-40 RANGE OVERNIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 317 AM CDT SAT JUL 20 2013
SYNOPTIC OVERVIEW...
20.00Z ECMWF/GFS/CANADIAN CONTINUE TO ADVERTISE THE NORTHWEST FLOW
PATTERN REMAINING IN PLACE THROUGH WEDNESDAY. HEADING INTO THURSDAY
AND FRIDAY...RIDGING STUCK OVER THE WESTERN U.S. MAY TRY TO SHIFT
EAST...BUT AT THE SAME TIME A VIGOROUS TROUGH IS PROGGED TO DROP
INTO NORTHERN ONTARIO AND LAKE SUPERIOR...EFFECTIVELY PREVENTING THE
RIDGE FROM BUILDING UP INTO THE FORECAST AREA.
SUNDAY INTO MONDAY NIGHT...
THE SHORTWAVE TROUGH OVER IOWA AND KS AT 12Z SUNDAY IS PROGGED TO
TRACK EAST THROUGH SOUTHERN SECTIONS OF THE FORECAST AREA LATE
SUNDAY. HARD TO SAY HOW MUCH ACTIVITY THERE MAY BE IN THE MORNING.
HOWEVER...INCREASING DAYTIME INSTABILITY COUPLED WITH THE APPROACH
OF THE SHORTWAVE AND A SURGE OF WARM ADVECTION SHOULD BE ENOUGH TO
PRODUCE SHOWERS AND STORMS OVER MUCH OF THE FORECAST AREA FOR THE
AFTERNOON. 20.00Z GFS/NAM/ECMWF/REGIONAL CANADIAN ALL HAVE PRECIP
FOR THE AFTERNOON...THUS THE 60 PERCENT CHANCES FROM THE PREVIOUS
FORECAST SEEMS REASONABLE. IF MODELS REMAIN CONSISTENT...THESE MAY
NEED TO BE RAISED FURTHER. AS THE SHORTWAVE TROUGH PUSHES EAST
SUNDAY NIGHT AND DIURNAL COOLING HAS ITS INFLUENCE ON THE
CONVECTION...EXPECT THE CONVECTION TO SLIDE EAST AND WEAKEN. DID
LOWER PRECIPITATION CHANCES AFTER MIDNIGHT INTO MONDAY MORNING.
20.00Z ECMWF EVEN SUGGESTS ALL OF SUNDAY NIGHT COULD END UP DRY.
ATTENTION THEN TURNS TO A VIGOROUS SHORTWAVE TROUGH CROSSING FROM
SOUTHERN MANITOBA INTO NORTHERN ONTARIO ON MONDAY. THE ASSOCIATED
COLD FRONT WITH THIS FEATURE LOOKS TO CROSS THE FORECAST AREA LATE
IN THE DAY INTO THE EVENING HOURS. THIS IS VERY GOOD TIMING BECAUSE
IT IS RIGHT AFTER PEAK HEATING. MONDAY SHOULD BE WARM AND HUMID AS
WELL AS SOUTHERLY WINDS AHEAD OF THE FRONT INCREASE TEMPS/DEWPOINTS.
925MB TEMPS CLIMBING TO 22-24C AT 18Z PER 20.00Z ECMWF EASILY BRINGS
HIGHS INTO THE 80S. WOULD NOT BE SURPRISED TO SEE A 90F. THERE ARE
THREE BIG QUESTION MARKS WITH THE FRONT...THOUGH:
1. HOW MUCH FORCING ALOFT WILL THERE BE. MOST MODELS DEPICT ALL THE
MID TO UPPER LEVEL FORCING STAYING TO THE NORTH OF THE AREA.
2. POTENTIAL FOR CAPPING AS A SURGE OF WARMER 800MB AIR FLOWS OUT OF
THE DAKOTAS AND INTO THE FORECAST AREA OVER THE FRONT.
3. 0-2 KM CONVERGENCE ON THE FRONT IS PROGGED TO BE WEAK AT
BEST...PARTIALLY DUE TO THE MID/UPPER FORCING WELL OFF TO THE NORTH.
GIVEN GOOD MODEL SIGNAL FOR PRECIPITATION...HAVE CHANCES IN THE
40-50 RANGE DURING THE FRONTAL PASSAGE. HOWEVER...GIVEN THE
QUESTIONS ABOVE...THE FRONT COULD COME THROUGH DRY OR MAYBE JUST
HAVE ISOLATED STORMS ALONG IT. SHOULD CONVECTION OCCUR...0-3KM SHEAR
VALUES APPROACH 30 KT WHICH COULD SUPPORT ISOLATED DAMAGING WINDS.
CONFIDENCE IS NOT PARTICULARLY HIGH FOR SEVERE...THOUGH.
TUESDAY THROUGH FRIDAY NIGHT...
DESPITE THE NORTHWEST FLOW ALOFT FOR TUESDAY THROUGH THURSDAY...
WHICH LOOKS TO CARRY A VARIETY OF WEAK SHORTWAVES THROUGH THE
FORECAST AREA WITH IT...20.00Z ECMWF/GFS/CANADIAN ARE IN PRETTY GOOD
AGREEMENT ON KEEPING THE FORECAST AREA DRY. THIS IS ALL BECAUSE OF
CANADIAN HIGH PRESSURE BUILDING IN BEHIND THE FRONTAL PASSAGE MONDAY
NIGHT. DRY AIR ASSOCIATED WITH THE HIGH EFFECTIVELY KEEPS THE AREA
DRY. MAY HAVE TO KEEP AN EYE ON THURSDAY FOR POSSIBLE INTRODUCTION
OF PRECIPITATION CHANCES SINCE THE HIGH PRESSURE AREA IS PROGGED TO
SHIFT OFF TO THE EAST. GIVEN THE CANADIAN NATURE OF THE
HIGH...EXPECT COOLER TEMPERATURES...ESPECIALLY COMPARED TO MONDAY.
850MB TEMPS GENERALLY HOVER BETWEEN 10-13C...SUPPORTING HIGHS IN THE
MID 70S TO NEAR 80. THE ECMWF REMAINS VERY CONSISTENT IN SHOWING A
STRONGER SHORTWAVE TRACKING OUT OF NEBRASKA THURSDAY NIGHT AND
HEADING SOUTHEAST INTO IL AND MO FRIDAY NIGHT. THE 20.00Z GFS IS
VERY SIMILAR. IF THESE MODEL SOLUTIONS END UP VERIFYING...AT A
MINIMUM THE SOUTHERN HALF OF THE FORECAST AREA LOOKS FAVORABLE TO
SEE SOME SHOWERS AND STORMS...ESPECIALLY ON FRIDAY. FOLLOWED THE
MODEL CONSENSUS FOR PRECIPITATION CHANCES...IN THE 30-40 RANGE.
ADDITIONALLY...IN THE WAKE OF THIS SHORTWAVE...ANOTHER CANADIAN HIGH
PRESSURE AREA IS AIMED TO DROP SOUTH TOWARDS THE FORECAST AREA FOR
NEXT WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 650 AM CDT SAT JUL 20 2013
VFR CONDITIONS EXPECTED AT THE TAF SITES TODAY ALONG WITH THE
POSSIBILITY OF SCATTERED THUNDERSTORMS DURING THE AFTERNOON AND
EARLY EVENING HOURS. A WEAK TROUGH WILL SAG SOUTH OUT OF NORTHERN
WISCONSIN TODAY AND POSSIBLY GENERATE SCATTERED THUNDERSTORMS THIS
AFTERNOON AS IT DRIFTS SOUTH THROUGH SOUTHEAST MINNESOTA AND
SOUTHWEST WISCONSIN. IF STORMS DEVELOP...THEY MAY PRODUCE GUSTY
WINDS AND SMALL HAIL. OTHERWISE PLAN ON A SCATTERED TO BROKEN
CEILINGS AT THE TAF SITES TODAY...WITH CLOUDS INCREASING DURING
THE AFTERNOON HOURS WITH CLOUD BASES IN THE 5 TO 8 KFT RANGE. SHOWERS
AND THUNDERSTORMS ARE POSSIBLE AGAIN LATE TONIGHT INTO SUNDAY
MORNING AS AN UPPER LEVEL TROUGH MOVES THROUGH THE AREA. THE BULK
OF THE ACTIVITY SHOULD OCCUR AFTER 12Z...WITH THE HIGHEST CHANCES
FOR SHOWERS AND STORMS SUNDAY AFTERNOON.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
552 AM MDT SAT JUL 20 2013
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 230 AM MDT SAT JUL 20 2013
FORECAST CHALLENGES DEAL WITH THUNDERSTORM CHANCES AND SEVERE
POSSIBILITIES THIS AFTERNOON.
CURRENTLY...PRETTY TRANQUIL WEATHER CONDITIONS ACROSS THE CWFA
THIS MORNING SO FAR. HAVE A FRONTAL BOUNDARY ANALYZED FROM KGCC TO
KRWL THIS MORNING ON SURFACE ANALYSIS. SURFACE LOW NEAR RIVERTON.
HAVE ANOTHER COLD FRONT PUSHING SOUTH NEAR BISMARK...EXTENDING
NORTHWEST INTO EASTERN MONTANA. LATEST FORECAST SOUNDINGS SHOWING
A CAPPING INVERSION IN THE LOWER LAYERS NEAR 700MBS. SEEING SOME
LIGHTNING STRIKES OUT NEAR RIVERTON...BUT SO FAR FOR THE CHEYENNE
CWFA...SKIES ARE PRETTY MUCH CLEAR.
SHOULD BEGIN TO SEE AN INCREASE IN SHOWERS AND THUNDERSTORMS LATER
ON TODAY AS THE NORTH DAKOTA COLD FRONT MOVES SOUTH INTO WESTERN
NEBRASKA THIS AFTERNOON. NORTHEAST UPSLOPING WINDS SHOULD HELP US
HERE EAST OF THE LARAMIE RANGE. 700MB CAPPING INVERSION ERODES BY
21Z OR SO WITH CAPES AROUND 1200 J/KG HERE AT CHEYENNE WITH NO
CONVECTIVE INHIBITION. LIFTED INDICES OUT IN THE PANHANDLE DOWN TO
-5C THIS AFTERNOON. CAPES UP TO 2000 J/KG OUT IN THE PANHANDLE. WENT
AHEAD AND INCREASED POPS A LITTLE EAST OF THE LARAMIE RANGE AND IN
THE PANHANDLE FOR THIS AFTERNOON AND ADDED SEVERE THUNDERSTORM
WORDING IN THE FORECAST FOR THE PANHANDLE. A SLIGHT RISK AREA HAS
BEEN ISSUED FOR THE PANHANDLE BY THE STORM PREDICTION CENTER. DAY
SHIFT MAY NEED TO UPDATE THE FORECAST FOR AREAS IN SOUTHEAST
WYOMING EAST OF THE LARAMIE RANGE BASED ON RADAR TRENDS LATER
TODAY. LATEST HRRR COMPOSITE REFLECTIVITY HAS THUNDERSTORMS
FORMING OVER THE LARAMIE RANGE AROUND 18Z...DRIFTING EASTWARD
TOWARDS THE PANHANDLE DURING THE AFTERNOON HOURS. STORMS ARE GOING
TO BE SLOW MOVING WITH STORM MOTION FORECASTS FROM THE NORTHWEST
UNDER 10KTS...SO THOSE FORTUNATE ENOUGH TO BE UNDER ONE OF THESE
STORMS SHOULD SEE QUITE A BIT OF RAINFALL. NAM PRECIPITABLE WATER
FORECASTS AROUND .9 INCHES HERE AT CHEYENNE AND 1.1 INCHES OUT
IN THE PANHANDLE. WITH RECENT RAINS OUT IN THE PANHANDLE...A FLASH
FLOOD THREAT COULD EXIST AS WELL. DAY SHIFT WILL NEED TO WATCH
THIS CLOSELY.
FRONTAL BOUNDARY SHIFTS EAST INTO CENTRAL NEBRASKA THIS EVENING
WITH SHOWERS AND THUNDERSTORMS COMING TO AN END TOWARDS MIDNIGHT.
SUNDAY LOOKS MAINLY DRY WEST OF THE LARAMIE RANGE AS AN UPPER
LEVEL RIDGE BUILDS INTO THE AREA. BEST CHANCES FOR SHOWERS AND
THUNDERSTORMS CONTINUES TO BE THE PANHANDLE AS THEY STAY IN THE
SOUTHEAST LOW LEVEL WIND FLOW THROUGH THE AFTERNOON. GFS AND ECMWF
SIMILAR ON QPF PLACEMENT FOR SUNDAY...SO KEPT CHANCE POPS GOING
EAST OF THE LARAMIE RANGE.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 111 AM MDT SAT JUL 20 2013
MEDIUM RANGE MODELS SHOW DRIER AIR PUSHING ACROSS SOUTHEAST
WYOMING AND INTO PORTIONS OF WESTERN NEBRASKA ON TUESDAY. UPPER
LEVEL HIGH PRESSURE WHICH HAS ESTABLISHED ITSELF ACROSS THE
WESTERN THIRD OF THE UNITED STATES MOST OF THIS SUMMER...WILL
DRIFT EAST OVER THE CENTRAL ROCKIES AND BUILD NORTHWARD. MIDLEVEL
SUBSIDENCE AND DRY NORTHWEST FLOW ALOFT WILL REDUCE CONVECTIVE
DEVELOPMENT ON TUESDAY...ALTHOUGH IT WILL BE RATHER MOIST NEAR THE
SURFACE ACROSS WESTERN NEBRASKA WHERE DEWPOINTS WILL REMAIN IN THE
50 TO 60 DEGREE RANGE WITH UPSLOPE EASTERLY WINDS. HIGH
TEMPERATURES IN THE 90S ARE EXPECTED ACROSS MOST OF THE FORECAST
AREA ON TUESDAY.
FOR THE MIDDLE OF THE WEEK...MODELS SHOW THE UPPER LEVEL FLOW
TRANSITIONING TO A MORE ZONAL PATTERN AS A FEW UPPER LEVEL
SHORTWAVES PUSH ACROSS THE NORTHERN AND CENTRAL ROCKIES. EXPECT
SLIGHTLY COOLER TEMPERATURES EACH DAY AND A HIGHER CHANCE OF
SHOWERS AND THUNDERSTORMS RETURNING TO THE REGION. WEDNESDAY
AFTERNOON IS TRICKY IN TERMS OF TSTORM CHANCES...WITH MODEL
SOUNDINGS SHOWING A CAPPED ENVIRONMENT WITH A WARM LAYER JUST
ABOVE 700MB. SOUNDINGS SHOW PW/S OVER 1 INCH AND CAPE OF 2500 J/KG
WITH BREEZY SOUTHEAST WINDS. NOT COMFORTABLE WITH POP BELOW 15
PERCENT NEAR THE MOUNTAINS...SO INCREASED POP AND ADDED A SLIGHT
CHANCE OF TSTORMS TO THE HIGH PLAINS ADJACENT OF THE LARAMIE
RANGE. CIN VALUES ARE BETWEEN -20 TO -50 J/KG IN THESE LOCATIONS
WHICH IS NOT QUITE ENOUGH TO PREVENT ISOLATED CONVECTION. ACROSS
THE PANHANDLE...CIN VALUES ARE OVER -200 J/KG WHICH SHOULD KEEP
THOSE AREAS DRY...AT LEAST INTO WEDNESDAY NIGHT. SCATTERED SHOWERS
AND TSTORMS WILL LIKELY RETURN TO ALL OF SOUTHEAST WYOMING AND
WESTERN NEBRASKA ON THURSDAY AS A VIGOROUS SHORT WAVE PUSHES
ACROSS THE AREA. FRIDAY WILL CONTINUE THIS TREND WITH COOLER
TEMPERATURES LOWERING INTO THE UPPER 70S TO LOW 80S FOR HIGHS WITH
WIDELY SCATTERED/SCATTERED TSTORMS POSSIBLE IN THE AFTERNOON AND
EVENING HOURS. WITH SUBTROPICAL MOISTURE FLOWING NORTHWARD...WILL
HAVE TO KEEP AN EYE ON FLASH FLOODING BY LATE NEXT WEEK.
&&
.AVIATION...(FOR THE 12Z TAF ISSUANCE)
VFR CONDITIONS WILL PREVAIL THIS MORNING THROUGH 18Z. SURFACE WINDS
WILL BE VARIABLE AT 10 KT OR LESS WITH CLEAR SKIES. THERE IS A
BETTER CHANCE OF THUNDERSTORMS FOR TERMINALS ACROSS THE HIGH PLAINS
INTO WESTERN NEBRASKA THIS AFTERNOON...MAINLY EAST OF THE LARAMIE
RANGE. STRONG GUSTY WINDS...FREQUENT LIGHTNING...AND SMALL HAIL WILL
BE THE MAIN CONCERNS WITH THESE THUNDERSTORMS THROUGH THIS EVENING.
&&
.FIRE WEATHER...
ISSUED AT 230 AM MDT SAT JUL 20 2013
ANOTHER CHANCE FOR WETTING RAINS MAINLY IN THE PANHANDLE AND EAST
OF THE LARAMIE RANGE THIS AFTERNOON. EASTERLY WINDS WILL BE LIGHT
TODAY AND ARE EXPECTED TO REMAIN LIGHT FROM THE EAST THROUGH
SUNDAY. DRIER CONDITIONS RETURN SUNDAY INTO NEXT WEEK AS HIGH
PRESSURE BUILDS INTO COLORADO. WE COULD BE LOOKING AT ELEVATED TO
CRITICAL FIRE WEATHER CONDITIONS TUESDAY AS WINDS INCREASE INTO
THE 25 TO 35 MPH RANGE. THIS IS DUE TO A LOW PRESSURE SYSTEM
MOVING THROUGH NORTHERN WYOMING AND MONTANA TUESDAY AFTERNOON.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...CLAYCOMB
LONG TERM...TJT
AVIATION...TJT
FIRE WEATHER...CLAYCOMB
AREA FORECAST DISCUSSION
NWS PUEBLO CO
307 PM MDT SAT JUL 20 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 230 PM MDT SAT JUL 20 2013
THE HIGHER LEVEL MSTR PLUME HAS SHIFTED SOUTH OF THE AREA
TODAY...BUT LOW LEVEL MSTR REMAINS IN PLACE WITH DEW POINTS MOSTLY
IN THE 50S OVR THE SERN PLAINS AND AROUND 50 IN THE SAN LUIS
VALLEY. EXPECTING MOST OF THE CONVECTIVE ACTIVITY THIS EVENING TO
BE OVR AND NR THE MTS. SO FAR TODAY...THE SHOWERS THAT HAVE
DEVELOPED WERE MOVING AROUND 10-12 MPH TO THE SE OR SSE. THIS SLOW
MOVEMENT WL AGAIN LEAD TO THE CONCERN FOR LOCALLY HEAVY RAIN ON THE
BURN SCARS AND THE POTENTIAL FOR FLASH FLOODING IF A HEAVIER STORM
MOVES OVR OR DEVELOPS ON A BURN SCAR. THE NAM AND HRRR MOVE SOME
STORMS OFF THE MTS AND ACRS THE I-25 CORRIDOR...MAINLY OVR EL PASO
AND NRN PUEBLO COUNTIES THIS EVENING. A SHORTWAVE TROF MOVING ACRS
NERN AND EAST CENTRAL CO TONIGHT IS EXPECTED TO BRING SOME
CONVECTIVE ACTIVITY TO THOSE AREAS...BUT AT THIS TIME THE HI RES
MODELS ARE KEEPING THAT MAINLY NORTH OF THE CWA...BUT COULD SEE SOME
SHOWERS/TSTMS IN KIOWA COUNTY ASSOC WITH THE DISTURBANCE. WE COULD
SEE A FEW LINGERING SHOWERS OVR THE MTS UNTIL MIDNIGHT OR A LITTLE
LATER...BUT THEN BY MORNING ALL AREAS SHOULD BE DRY.
ON SUN IT LOOKS LIKE SOME ISOLD TO SCT SHOWER/TSTMS COULD DEVELOP
OVR THE HYR TRRN AROUND NOON...WITH THE BEST CHANCES BEING OVR THE
SW MTS AND THE SRN SANGRES. A WEAK DISTURBANCE IS EXPECTED TO MOVE
ACRS NERN CO IN THE AFTERNOON...AND THE NAM HAS SOME CONVECTIVE
ACTIVITY FIRING UP IN NORTHEAST AND EAST CENTRAL CO...INCLUDING
KIOWA AND CROWLEY COUNTIES BY EVENING. THE GFS KEEPS THE CONVECTION
OVR NERN CO. FOR NOW WL GO WITH A DRY FORECAST FOR THE FAR SERN
PLAINS SUN AFTERNOON. HIGH TEMPS ON SUN LOOK A COUPLE OR FEW DEGREES
WARMER THAN TODAY.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 230 PM MDT SAT JUL 20 2013
HOT AND MAINLY DRY CONDITIONS EXPECTED MON AND TUESDAY AS UPPER
RIDGE RE-AMPLIFIES OVER THE WESTERN US. MOISTURE PLUME WILL REMAIN
SUPPRESSED TO THE SOUTH BOTH DAYS...THOUGH PERHAPS JUST ENOUGH
RESIDUAL LOW LEVEL MOISTURE WILL LINGER TO PRODUCE AN ISOLATED
HIGH BASED TSRA OVER THE MOUNTAINS...ESPECIALLY MON. WITH HEIGHTS
RISING AND 700 MB TEMPS CLIMBING TOWARD 20C...EXPECT MAX TEMPS
MON/TUE WILL REACH 100F PLUS OVER THE LOWER ARKANSAS VALLEY...WITH
80S/90S ELSEWHERE. FRONT DROPS THROUGH THE EASTERN PLAINS LATE TUE
NIGHT/EARLY WED...LEADING TO A RENEWED WESTWARD PUSH OF MOISTURE
BY WED AFTERNOON. ECMWF HAS TRENDED TOWARD THE GFS ON WED...AND
BOTH MODELS NOW SUGGEST INCREASED CHANCES FOR TSRA OVER THE
EASTERN MOUNTAINS AND PLAINS WED AFTERNOON/EVENING. WESTERN
MOUNTAINS AND VALLEYS SHOULD ALSO SEE AN UPSWING IN TSRA WED...AS
WEAK PUSH OF MID LEVEL MOISTURE WORKS NORTHWARD UNDERNEATH THE
UPPER RIDGE AXIS. FOR LATE WEEK INTO THE WEEKEND...STILL APPEARS
AN INCREASE IN CONVECTION IS POSSIBLE MANY AREAS THU-SAT...THOUGH
DIFFERENCES BETWEEN THE EUROPEAN AND GFS ARISE BEGINNING THU...AS
EURO BRINGS A STRONG TROUGH THROUGH THE AREA...WHILE GFS IS
WEAKER/SLOWER. GFS IS THUS RATHER DRY THU...THEN MOISTENS THE AREA
FRI/SAT...WHILE FASTER ECMWF IS WETTER THU/FRI BEFORE DRYING
SLIGHTLY ON SAT. HAVE FOLLOWED THE MORE CONSISTENT GFS AT THIS
POINT...BUT MAIN MESSAGE OF BOTH MODELS IS A RETURN OF FAIRLY
WIDESPREAD CONVECTION BY WEEK`S END.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 230 PM MDT SAT JUL 20 2013
SHOWERS AND THUNDERSTORMS COULD OCCUR AT OR IN THE VCNTY OF
KCOS...KALS AND KPUB MAINLY BEFORE 02Z-03Z. IT IS POSSIBLE THAT SOME
HEAVY RAIN COULD AFFECT THE TERMINAL SITES WITH BRIEF MVFR OR IFR
CONDITIONS. OTHERWISE VFR CONDITIONS ARE EXPECTED.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...28
LONG TERM...PETERSEN
AVIATION...28
AREA FORECAST DISCUSSION
NWS WICHITA KS
113 PM CDT SAT JUL 20 2013
.UPDATE...
ISSUED AT 1253 PM CDT SAT JUL 20 2013
OUTFLOW BOUNDARY FROM CONVECTION ACROSS NORTHEAST KANSAS HAS MOVED
INTO AND ACROSS EASTERN SECTION OF CWA...AND IS SPARKING TSRA ACROSS
PORTIONS OF THE EASTERN FLINT HILLS...AS BOUNDARY ENCOUNTERS GREATER
THETAE. FLOW ALOFT IS VERY WEAK...THUS HEALTHY CAPE WILL BE THE ONLY
DRIVER FOR STORM INTENSITY. RUC/HRRR BOTH INDICATE AN INCREASE IN
ISOLD-WDLY SCT CONVECTION THIS AFTERNOON INTO EARLY EVENING...THUS WILL
UPDATE HOURLY POPS TO ACCOUNT. ALSO WILL ADJUST HOURLY
TEMPERATURES AND MAX TEMPERATURES IN EXTREME SOUTHEAST CWA...WHERE
THINGS ARE WARMING MORE THAN ANTICIPATED. NO OTHER CHANGES ATTM.
SF
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 344 AM CDT SAT JUL 20 2013
TODAY-TONIGHT:
LOW CONFIDENCE FORECAST WITH SHORT TERM/HIGH RESOLUTION GUIDANCE
SHOWING MANY POSSIBLE SCENARIOS AND MOST HAVE BEEN STRUGGLING OUT
OF THE BOX. HAVE USED A COMBO OF HRRR AND ECMWF AS BOTH NAM/GFS
SEEM QUITE OPTIMISTIC WITH CAPE/PRECIPITATION FOR LATER TODAY.
WEAK FLOW ALOFT MAKES IT HARD TO DETERMINE WHERE THINGS WILL MOVE
AND GIVEN WEAK FORCING...BOUNDARIES WILL LIKELY BE THE KEY TO
CONVECTIVE INITIATION. AT THIS TIME...THINKING WEAK SURFACE
BOUNDARY FROM GBD-RSL-MHK WILL LIKELY NOT MOVE VERY MUCH...SO WILL
DRIBBLE ISOLATED POPS ALONG/NORTH OF BOUNDARY THIS MORNING.
CHANCES SHOULD INCREASE A BIT LATE AFTERNOON BUT MORE LIKELY THIS
EVENING. ECMWF KEEPS THE BULK OF THE PRECIPITATION IN CENTRAL KS
OVERNIGHT AND POPS MAY BE OVERDONE ACROSS THE SOUTHERN HALF OF THE
AREA.
SUN-MON:
BETTER UPPER FORCING IS ANTICIPATED AS DAY WEARS ON SUN BUT
FORECAST IS COMPLICATED BY POSSIBLE OUTFLOW FROM STORMS OVER NE KS
IN THE MORNING. SUSPECT ANOTHER ROUND OF STORMS WILL DEVELOP IN
NORTHWEST FLOW AND MOVE ACROSS FLINT HILLS/SOUTHEAST KS SUN NIGHT.
THIS SHOULD EXIT SOUTHEAST KS AROUND SUNRISE. MAY SEE SOME
INCREASE IN CAPPING ON MON AND GIVEN LESS FORCING...PRECIPITATION
CHANCES SHOULD DIMINISH. SHADED TEMPERATURES DOWN A BIT IN THE
EASTERN HALF AND WARMER IN WEST BASED ON CLOUDS BOTH DAYS.
-HOWERTON
.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 344 AM CDT SAT JUL 20 2013
AGAIN FAIRLY GOOD AGREEMENT BETWEEN 0000 UTC RUNS OF GFS/ECMWF
OVERALL PATTERN UNTIL FRI. HOWEVER DETAILS ON PRECIPITATION CHANCES
ARE STILL IN LESS AGREEMENT AND COMBINED WITH GRID INITIALIZATION
ISSUES...WILL END UP WITH CONSIDERABLE PRECIPITATION MENTIONED THIS
PERIOD. STILL APPEARS TO BE AN INCREASED CHANCE FOR PRECIPITATION
TUE NIGHT AS SHORTWAVE MOVES DOWN NORTHWEST FLOW. SURFACE FRONT
MAY BE MOVING INTO THE AREA ON FRI...BUT UNCERTAINTY IS HIGH ON
TIMING. -HOWERTON
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1253 PM CDT SAT JUL 20 2013
MAIN CONCERN FOR THE TAF PERIOD WILL BE PERIODS OF ISOLD-SCATTERED CONVECTION.
FORECAST SOUNDINGS INDICATE CONVECTIVE TEMPERATURES WILL BE
REACHED IN THE NEXT HOUR OR TWO...AND WITH SUFFICIENT MID-LEVEL
MOISTURE...ALL TAF SITES SHOULD BEGIN TO SEE TCU/CB DEVELOPMENT
BY 20 UTC. COVERAGE WILL BE LOCALLY DEPENDENT...BUT STARTED WITH
SCT COVERAGE AND INCREASED TO BKN BY 22-23 UTC. CONFIDENCE OF TSRA
OCCURRING AT ANY PARTICULAR TAF SITE IS LOW...THOUGH GREATEST
CHANCES LIKELY AT KICT...KSLN...KCNU AND KHUT DUE TO THEIR PROXIMITY
TO OUTFLOW BOUNDARY THAT HAS MOVED INTO CWA AND IS STALLING. GIVEN CONVECTION
MAINLY WILL BE DIURNALLY DRIVEN...EXPECTED ANY STORMS THAT FIRE
THIS AFTERNOON TO DISSIPATE IN THE 03-04 UTC TIMEFRAME. ANOTHER
ROUND OF CONVECTION WILL BE POSSIBLE AFT 06 UTC...WITH
ENHANCED/FOCUSED ISENTROPIC LIFT THAT WILL BE ENHANCED BY RRQ OF
UPPER JET. REINTRODUCED CONVECTION IN 07-09 UTC TIMEFRAME AS A RESULT.
ISENTROPIC FIELDS LINGER CONVECTION AND CONVECTIVE DEBRIS INTO
SUNDAY MORNING. FORECAST SOUNDINGS PLACING TSRA BASES IN THE 6-8K
AGL RANGE.
SF
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 96 72 93 73 / 20 20 20 20
HUTCHINSON 95 70 94 71 / 20 20 20 20
NEWTON 93 70 92 70 / 20 30 30 20
ELDORADO 94 71 92 70 / 20 20 30 30
WINFIELD-KWLD 96 73 93 74 / 20 20 20 20
RUSSELL 94 67 98 68 / 30 30 20 20
GREAT BEND 94 66 97 68 / 20 20 20 20
SALINA 95 70 94 71 / 30 40 40 30
MCPHERSON 95 70 94 70 / 30 30 30 20
COFFEYVILLE 97 72 94 72 / 20 20 20 40
CHANUTE 94 71 92 71 / 20 30 30 40
IOLA 93 71 91 71 / 30 30 40 40
PARSONS-KPPF 96 72 93 71 / 20 20 30 40
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1250 PM CDT SAT JUL 20 2013
...UPDATE TO AVIATION...
.UPDATE...
ISSUED AT 1144 AM CDT SAT JUL 20 2013
WEAK ISENTROPIC LIFT CONTINUES JUST NORTH OF THE FRONTAL BOUNDARY
STRETCHED FROM SALINA TO MANHATTAN...TO OSKALOOSA IN JEFFERSON
COUNTY. ALSO OBSERVING TWO OUTFLOW BOUNDARIES MOVING THROUGH
SOUTHEAST NEBRASKA INTO MARSHALL AND WASHINGTON COUNTIES WHERE
THE ONGOING SHOWERS AND THUNDERSTORMS ARE BEING ABLE TO REDEVELOP
AND MAINTAIN THEMSELVES. CHANGES MADE TO THE CURRENT FORECAST
INCLUDED ADDING PRECIPITATION CHANCES OVER MUCH OF NORTH CENTRAL
AND NORTHEAST KANSAS THROUGH THE AFTERNOON. ALSO ADJUST TEMPERATURES
DOWN SLIGHTLY OVER NORTH CENTRAL/NORTH EAST AREAS WHERE CLOUD
COVER AND RAIN PERSISTS. WILL CONTINUE TO MONITOR FORECAST AS
AREAS OF ADDITIONAL THUNDERSTORM DEVELOPMENT LATE THIS AFTERNOON
ARE DEPENDENT ON LOCATION OF THE FRONT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT SAT JUL 20 2013
TODAY AND TONIGHT...A LONGER WAVE LENGTH UPPER LEVEL TROUGH WILL
CONTINUE TO AMPLIFY ACROSS THE UPPER MIDWEST AND GREAT LAKES STATES.
THIS WILL CAUSE THE UPPER FLOW ACROSS THE PLAINS TO BECOME
NORTHWESTERLY. SHORTER WAVE LENGTH UPPER LEVEL TROUGHS WILL ROUND
THE UPPER RIDGE AXIS ACROSS THE WESTERN CONUS AND DIG SOUTHEAST
ACROSS THE CENTRAL PLAINS THROUGH TONIGHT. A WEAK FRONTAL BOUNDARY
WAS LOCATED FROM SOUTHWEST KS...NORTHEAST TO NEAR TOP...THEN
NORTHEAST ACROSS NORTHERN MO. WEAK ISENTROPIC LIFT NORTH OF THE
BOUNDARY MAY CAUSE A FEW SHOWERS TO DEVELOP THIS MORNING ACROSS EAST
CENTRAL KS.
MOST NUMERICAL MODELS SHOW AN H5 TROUGH DIGGING SOUTHEAST ACROSS
CENTRAL HIGH PLAINS DURING THE AFTERNOON HOURS. THE ASCENT AHEAD OF
THE H5 TROUGH COMBINED WITH UPSLOPE FLOW WILL CAUSE A COMPLEX OF
THUNDERSTORMS TO DEVELOP ACROSS WESTERN NE LATE THIS AFTERNOON AND
EARLY EVENING...THEN MOVE SOUTHEAST ACROSS EASTERN KS LATER TONIGHT.
ISOLATED TO WIDELY SCATTERED THUNDERSTORMS MAY ALSO DEVELOP ALONG
THE NORTHWARD MOVING FRONTAL BOUNDARY ACROSS THE CWA DURING THE LATE
AFTERNOON AND EARLY EVENING HOURS. THE 00Z NAM AND RAP MODELS WERE
SHOWING 1500-2500 J/KG OF MLCAPE. HOWEVER...THE SFC-6KM EFFECTIVE
SHEAR WILL ONLY BE 15 TO 20 KTS DURING THE AFTERNOON AND EARLY
EVENING HOURS. DUE TO THE WEAKER VERTICAL WINDSHEAR UPDRAFTS WILL
PROBABLY NOT BE ABLE TO SUSTAIN THEIR INTENSITY FOR MORE THAN 15 TO
20 MINUTES. THE STRONGER THUNDERSTORMS MAY PRODUCE SMALL HAIL AND 40
TO 50 MPH WINDS GUSTS. A STORM OR TWO MAY BRIEFLY PRODUCE QUARTER
SIZE HAIL AND 58 MPH WINDS GUSTS.
THE INSTABILITY AND VERTICAL WIND SHEAR AND INSTABILITY LOOKS TOO
WEAK FOR THE COMPLEX OF THUNDERSTORMS LATE TONIGHT TO BE
SEVERE...SOME OF THE STRONGER STORMS MAY PRODUCE GUSTY WINDS AND
THERE COULD BE HEAVY RAINFALL ALONG THE TRACK OF THE THUNDERSTORM
COMPLEX. I KEPT LIKELY POPS FOR THE NORTHERN AND EASTERN COUNTIES OF
THE CWA AFTER MIDNIGHT. THIS MAY CHANGE DEPENDING TO WHERE THE MCS
ACROSS NE FORMS AND HOW IT TRACKS THROUGH THE NIGHT. ATTM...MOST
MODELS HAVE THE COMPLEX OF STORMS MOVING SOUTHEAST ACROSS SOUTH
CENTRAL NE AND ACROSS THE EASTERN CWA LATE TONIGHT AND THROUGH THE
MORNING HOURS OF SUNDAY.
BROKEN TO SCATTED CLOUD COVER AND LIGHT SOUTHEAST WINDS WILL KEEP
HIGH TEMPERATURES TODAY IN THE LOWER TO MID 90S ACROSS THE CWA.
HIGHER SURFACE DEWPOINTS IN THE MID TO UPPER 60S WILL CAUSE HEAT
INDICES TO RISE INTO THE UPPER 90S.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 350 AM CDT SAT JUL 20 2013
THE COMBINATION OF PERSISTENT UPPER RIDGING IN THE INTERMOUNTAIN
WEST AND TROUGHING IN THE GREAT LAKES AREA WILL PRIMARILY KEEP THE
COUNTY WARNING AREA IN NORTHWEST FLOW ALOFT THROUGH THE END OF THE
UPCOMING WORK WEEK. IN GENERAL THIS WILL KEEP AN AXIS OF LOW LEVEL
MOISTURE IN PLACE FROM KS WEST AND NORTHWESTWARD INTO THE CENTRAL
HIGH PLAINS THROUGH THE PERIOD. AS A SERIES OF SHORTWAVE TROUGHS
MOVING THROUGH THE FLOW ALOFT...THERE WILL BE (DEPENDING ON THE
TIMING OF EACH SHORTWAVE) THE OPPORTUNITY FOR CONVECTION TO DEVELOP
AND MOVE EAST AND SOUTHEAST WITHIN THIS MOISTURE AXIS...ALTHOUGH THE
LLVL JET WILL NOT BE PARTICULARLY STRONG THIS SETUP ALONG WITH
POSSIBLE OUTFLOW/WEAK FRONTAL BOUNDARIES FROM EARLIER MCS`S SHOULD
PROVIDE SEVERAL OPPORTUNITIES FOR RAIN IN THE WEEK AHEAD. ALTHOUGH
THE MODELS OFFER DIFFERENT SOLUTIONS ON THE STRENGTH AND TIMING OF
THESE SHORTWAVE TROUGHS...THE BETTER CHANCES FOR THUNDERSTORMS
APPEARS TO BE SUNDAY INTO SUNDAY NIGHT WITH THE PASSAGE OF A
SHORTWAVE TROUGH...THEN AGAIN WITH AN STRONGER WAVE TUESDAY NIGHT
INTO WEDNESDAY MORNING. FOCUSED THE HIGHER POPS IN THESE PERIODS
WHERE PERSISTENT AND CONFIDENCE IS HIGHER. MESOSCALE FEATURES WITH
ANY MCS`S WILL LIKELY COMPLICATE THE FORECAST FROM DAY TO DAY.
ANOTHER CHALLENGE THIS WEEK IN THIS PATTERN WILL BE TEMPERATURES
AS THE CWA WILL FREQUENTLY BE LOCATED ON THE EASTERN PERIPHERY OF A
STRONG THERMAL AXIS MUCH OF THE WEEK. AS THE LLVL FLOW VEERS...THERE
WILL BE AN ENHANCED OPPORTUNITY FOR VERY WARM AIR TO BE ADVECTED
EASTWARD INTO THE CWA. THIS OCCURS ON MONDAY INTO TUESDAY...WITH
SOME INDICATIONS OF ANOTHER SURGE OF MUCH WARMER AIR TOWARDS THE END
OF THE WEEK. HOWEVER...PERIODIC CHANCES FOR PRECIP/THICKER CLOUDS
WILL CONTINUE TO BE POSSIBLE OFFSETTING FACTORS. WILL MAINTAIN
HIGHS GENERALLY IN THE 90S THROUGH THE FCST...ALTHOUGH THE EFFECTS
OF CLOUDS/PRECIP ON SUNDAY WILL LIMIT HIGHS TO THE 80S IN MANY AREAS
SUNDAY WITH POST FRONTAL HIGHS ON WEDNESDAY IN THE 80S AS WELL. AT
THIS POINT...THE HIGHEST HEAT INDICES THIS WEEK APPEAR WILL OCCUR ON
MONDAY WITH READINGS COMMONLY IN THE RANGE OF 100 TO 104 DEGREES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1238 PM CDT SAT JUL 20 2013
VFR CONDITIONS WILL BE THE PREVAILING CATEGORY AT KTOP/KFOE/KMHK.
CURRENTLY TRACKING A STATIONARY FRONT POSITIONED JUST NORTH OF THE
TERMINALS AT 18Z. SCATTERED TSRA IS POSSIBLE ALONG THIS BOUNDARY
AND WITH SOME UNCERTAINTY AS TO WHERE BOUNDARY WILL INITIATE
STORMS DECIDED TO INSERT VCTS AT SITES AFT 21Z. CONFIDENCE
DECREASES IN PRECIPITATION IMPACTING TERMINALS OVERNIGHT AS ANOTHER
WAVE SHIFTS SOUTHEAST INTO NORTHEAST KANSAS. SHOULD SEE MOSTLY
RAIN SHOWERS WITH THUNDERSTORMS EMBEDDED AFT 07Z AT KMHK AND 08Z
AT KTOP/KFOE. EXACT TIMING OF THESE STORMS MAY NEED TO BE REFINED
AS THEY EVOLVE OVER SOUTHERN NEBRASKA. STORMS WILL BE ELEVATED WITH
PERHAPS A BRIEF PERIOD OF MVFR UNDERNEATH ANY HEAVIER THUNDERSTORM.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...BOWEN
SHORT TERM...GARGAN
LONG TERM...63
AVIATION...BOWEN
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1158 AM CDT SAT JUL 20 2013
.UPDATE...
ISSUED AT 1144 AM CDT SAT JUL 20 2013
WEAK ISENTROPIC LIFT CONTINUES JUST NORTH OF THE FRONTAL BOUNDARY
STRETCHED FROM SALINA TO MANHATTAN...TO OSKALOOSA IN JEFFERSON
COUNTY. ALSO OBSERVING TWO OUTFLOW BOUNDARIES MOVING THROUGH
SOUTHEAST NEBRASKA INTO MARSHALL AND WASHINGTON COUNTIES WHERE
THE ONGOING SHOWERS AND THUNDERSTORMS ARE BEING ABLE TO REDEVELOP
AND MAINTAIN THEMSELVES. CHANGES MADE TO THE CURRENT FORECAST
INCLUDED ADDING PRECIPITATION CHANCES OVER MUCH OF NORTH CENTRAL
AND NORTHEAST KANSAS THROUGH THE AFTERNOON. ALSO ADJUST TEMPERATURES
DOWN SLIGHTLY OVER NORTH CENTRAL/NORTH EAST AREAS WHERE CLOUD
COVER AND RAIN PERSISTS. WILL CONTINUE TO MONITOR FORECAST AS
AREAS OF ADDITIONAL THUNDERSTORM DEVELOPMENT LATE THIS AFTERNOON
ARE DEPENDENT ON LOCATION OF THE FRONT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT SAT JUL 20 2013
TODAY AND TONIGHT...A LONGER WAVE LENGTH UPPER LEVEL TROUGH WILL
CONTINUE TO AMPLIFY ACROSS THE UPPER MIDWEST AND GREAT LAKES STATES.
THIS WILL CAUSE THE UPPER FLOW ACROSS THE PLAINS TO BECOME
NORTHWESTERLY. SHORTER WAVE LENGTH UPPER LEVEL TROUGHS WILL ROUND
THE UPPER RIDGE AXIS ACROSS THE WESTERN CONUS AND DIG SOUTHEAST
ACROSS THE CENTRAL PLAINS THROUGH TONIGHT. A WEAK FRONTAL BOUNDARY
WAS LOCATED FROM SOUTHWEST KS...NORTHEAST TO NEAR TOP...THEN
NORTHEAST ACROSS NORTHERN MO. WEAK ISENTROPIC LIFT NORTH OF THE
BOUNDARY MAY CAUSE A FEW SHOWERS TO DEVELOP THIS MORNING ACROSS EAST
CENTRAL KS.
MOST NUMERICAL MODELS SHOW AN H5 TROUGH DIGGING SOUTHEAST ACROSS
CENTRAL HIGH PLAINS DURING THE AFTERNOON HOURS. THE ASCENT AHEAD OF
THE H5 TROUGH COMBINED WITH UPSLOPE FLOW WILL CAUSE A COMPLEX OF
THUNDERSTORMS TO DEVELOP ACROSS WESTERN NE LATE THIS AFTERNOON AND
EARLY EVENING...THEN MOVE SOUTHEAST ACROSS EASTERN KS LATER TONIGHT.
ISOLATED TO WIDELY SCATTERED THUNDERSTORMS MAY ALSO DEVELOP ALONG
THE NORTHWARD MOVING FRONTAL BOUNDARY ACROSS THE CWA DURING THE LATE
AFTERNOON AND EARLY EVENING HOURS. THE 00Z NAM AND RAP MODELS WERE
SHOWING 1500-2500 J/KG OF MLCAPE. HOWEVER...THE SFC-6KM EFFECTIVE
SHEAR WILL ONLY BE 15 TO 20 KTS DURING THE AFTERNOON AND EARLY
EVENING HOURS. DUE TO THE WEAKER VERTICAL WINDSHEAR UPDRAFTS WILL
PROBABLY NOT BE ABLE TO SUSTAIN THEIR INTENSITY FOR MORE THAN 15 TO
20 MINUTES. THE STRONGER THUNDERSTORMS MAY PRODUCE SMALL HAIL AND 40
TO 50 MPH WINDS GUSTS. A STORM OR TWO MAY BRIEFLY PRODUCE QUARTER
SIZE HAIL AND 58 MPH WINDS GUSTS.
THE INSTABILITY AND VERTICAL WIND SHEAR AND INSTABILITY LOOKS TOO
WEAK FOR THE COMPLEX OF THUNDERSTORMS LATE TONIGHT TO BE
SEVERE...SOME OF THE STRONGER STORMS MAY PRODUCE GUSTY WINDS AND
THERE COULD BE HEAVY RAINFALL ALONG THE TRACK OF THE THUNDERSTORM
COMPLEX. I KEPT LIKELY POPS FOR THE NORTHERN AND EASTERN COUNTIES OF
THE CWA AFTER MIDNIGHT. THIS MAY CHANGE DEPENDING TO WHERE THE MCS
ACROSS NE FORMS AND HOW IT TRACKS THROUGH THE NIGHT. ATTM...MOST
MODELS HAVE THE COMPLEX OF STORMS MOVING SOUTHEAST ACROSS SOUTH
CENTRAL NE AND ACROSS THE EASTERN CWA LATE TONIGHT AND THROUGH THE
MORNING HOURS OF SUNDAY.
BROKEN TO SCATTED CLOUD COVER AND LIGHT SOUTHEAST WINDS WILL KEEP
HIGH TEMPERATURES TODAY IN THE LOWER TO MID 90S ACROSS THE CWA.
HIGHER SURFACE DEWPOINTS IN THE MID TO UPPER 60S WILL CAUSE HEAT
INDICES TO RISE INTO THE UPPER 90S.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 350 AM CDT SAT JUL 20 2013
THE COMBINATION OF PERSISTENT UPPER RIDGING IN THE INTERMOUNTAIN
WEST AND TROUGHING IN THE GREAT LAKES AREA WILL PRIMARILY KEEP THE
COUNTY WARNING AREA IN NORTHWEST FLOW ALOFT THROUGH THE END OF THE
UPCOMING WORK WEEK. IN GENERAL THIS WILL KEEP AN AXIS OF LOW LEVEL
MOISTURE IN PLACE FROM KS WEST AND NORTHWESTWARD INTO THE CENTRAL
HIGH PLAINS THROUGH THE PERIOD. AS A SERIES OF SHORTWAVE TROUGHS
MOVING THROUGH THE FLOW ALOFT...THERE WILL BE (DEPENDING ON THE
TIMING OF EACH SHORTWAVE) THE OPPORTUNITY FOR CONVECTION TO DEVELOP
AND MOVE EAST AND SOUTHEAST WITHIN THIS MOISTURE AXIS...ALTHOUGH THE
LLVL JET WILL NOT BE PARTICULARLY STRONG THIS SETUP ALONG WITH
POSSIBLE OUTFLOW/WEAK FRONTAL BOUNDARIES FROM EARLIER MCS`S SHOULD
PROVIDE SEVERAL OPPORTUNITIES FOR RAIN IN THE WEEK AHEAD. ALTHOUGH
THE MODELS OFFER DIFFERENT SOLUTIONS ON THE STRENGTH AND TIMING OF
THESE SHORTWAVE TROUGHS...THE BETTER CHANCES FOR THUNDERSTORMS
APPEARS TO BE SUNDAY INTO SUNDAY NIGHT WITH THE PASSAGE OF A
SHORTWAVE TROUGH...THEN AGAIN WITH AN STRONGER WAVE TUESDAY NIGHT
INTO WEDNESDAY MORNING. FOCUSED THE HIGHER POPS IN THESE PERIODS
WHERE PERSISTENT AND CONFIDENCE IS HIGHER. MESOSCALE FEATURES WITH
ANY MCS`S WILL LIKELY COMPLICATE THE FORECAST FROM DAY TO DAY.
ANOTHER CHALLENGE THIS WEEK IN THIS PATTERN WILL BE TEMPERATURES
AS THE CWA WILL FREQUENTLY BE LOCATED ON THE EASTERN PERIPHERY OF A
STRONG THERMAL AXIS MUCH OF THE WEEK. AS THE LLVL FLOW VEERS...THERE
WILL BE AN ENHANCED OPPORTUNITY FOR VERY WARM AIR TO BE ADVECTED
EASTWARD INTO THE CWA. THIS OCCURS ON MONDAY INTO TUESDAY...WITH
SOME INDICATIONS OF ANOTHER SURGE OF MUCH WARMER AIR TOWARDS THE END
OF THE WEEK. HOWEVER...PERIODIC CHANCES FOR PRECIP/THICKER CLOUDS
WILL CONTINUE TO BE POSSIBLE OFFSETTING FACTORS. WILL MAINTAIN
HIGHS GENERALLY IN THE 90S THROUGH THE FCST...ALTHOUGH THE EFFECTS
OF CLOUDS/PRECIP ON SUNDAY WILL LIMIT HIGHS TO THE 80S IN MANY AREAS
SUNDAY WITH POST FRONTAL HIGHS ON WEDNESDAY IN THE 80S AS WELL. AT
THIS POINT...THE HIGHEST HEAT INDICES THIS WEEK APPEAR WILL OCCUR ON
MONDAY WITH READINGS COMMONLY IN THE RANGE OF 100 TO 104 DEGREES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 602 AM CDT SAT JUL 20 2013
ISOLATED TO WIDELY SCATTERED THUNDERSTORMS WILL CONTINUE ACROSS
THE TAF SITES THROUGH 15Z. OTHERWISE...EXPECT VFR CONDITIONS FOR THE
LATE MORNING AND EARLY AFTERNOON. THERE WILL BE ANOTHER CHANCE FOR
SCATTERED THUNDERSTORMS LATE THIS AFTERNOON THROUGH THE MID
EVENING HOURS. LATE IN THE TAF PERIOD THERE COULD BE ANOTHER
CHANCE OF THUNDERSTORMS BUT DUE TO TIMING ISSUES I HAVE NOT
INCLUDED A VCTS GROUP FOR STORMS THAT MAY ARRIVE AROUND SUNRISE ON
SUNDAY.
GARGAN
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...BOWEN
SHORT TERM...GARGAN
LONG TERM...63
AVIATION...GARGAN
AREA FORECAST DISCUSSION
NWS JACKSON KY
528 PM EDT SAT JUL 20 2013
.UPDATE...
ISSUED AT 527 PM EDT SAT JUL 20 2013
BASED ON CURRENT RADAR TRENDS...DIDN/T FEEL CONFIDENT IN NO POPS
ACROSS THE AREA THIS AFTERNOON/EVENING. WENT AHEAD AND ADDED IN SOME
SLIGHT CHANCES ALONG THE NORTHERN AND SOUTHEASTERN SECTIONS OF THE
CWA THROUGH THIS AFTERNOON IN CASE SOME SHORT LIVED CONVECTION
DEVELOPS. THEN HAVE ISOLATED CHANCES TAPERING OFF ACROSS THE
SOUTHEAST THIS EVENING AS BEST INSTABILITY BECOMES FOCUSED OVER THE
NORTHERN CWA WITH AN IMPOSING COLD FRONT AND AREA OF CONVECTION
MOVING INTO THE REGION.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 325 PM EDT SAT JUL 20 2013
CONTINUING TO WATCH SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS
DROPPING SOUTHWARD ACROSS THE OHIO RIVER VALLEY. A GAP IN THE LINE
HAS OPENED UP JUST TO OUR NORTH. WHILE SHOWERS AND STORMS ARE STILL
POSSIBLE THIS EVENING INTO TONIGHT...EVERY HRRR RUN OVER THE PAST
SEVERAL HOURS CONTINUES TO BACK OFF ON OVERALL COVERAGE ACROSS
EASTERN KENTUCKY THIS EVENING...WITH EVERYTHING FADING AWAY AROUND
SUNSET. THUS...HAVE DECREASED POPS INTO THIS EVENING AND THE
OVERNIGHT HOURS. THIS TREND MAY HAVE TO BE CONTINUED ON THE EVENING
SHIFT IF THE TRENDS CONTINUE THE WAY THEY ARE HEADING.
REGARDLESS...THE PROSPECTS FOR WIDESPREAD SHOWERS AND THUNDERSTORMS
IS DRASTICALLY LESS NOW. WILL MAINTAIN LOW 20-30 POPS THROUGH THE
OVERNIGHT HOURS. WITH THE BOUNDARY WASHED OUT OVER THE AREA
TOMORROW...DAYTIME HEATING SHOULD ALLOW FOR QUICK REDEVELOPMENT AFTER
SUNRISE. COVERAGE SHOULD BE DECENT TOMORROW...SO OPTED TO STAY WITH
OUR 60-70 POPS. THERE IS SOME QUESTION AS TO HOW MUCH ACTIVITY WILL
THEN LINGER INTO TOMORROW NIGHT AS THE QUASI BOUNDARY MAY SHIFT BACK
TO THE NORTH. LACK OF OVERNIGHT INSTABILITY MAY KEEP THINGS FAIRLY
LOW KEY FOR MUCH OF THE NIGHT. THERE IS A SHORTWAVE TROUGH PUSHING
ACROSS THE AREA LATE IN THE NIGHT THAT COULD ACT TO FIRE OFF SOME
SHOWERS AND THUNDERSTORMS...SO WILL INCREASE POPS THROUGH THE NIGHT.
TEMPERATURES ON SUNDAY SHOULD BE SLIGHTLY LOWER WITH THE INCREASED
CLOUD COVER AND PRECIPITATION.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 325 PM EDT SAT JUL 20 2013
THE MODELS BASICALLY AGREE ON THE GENERAL MID LEVEL PATTERN THROUGH
THE BULK OF THE EXTENDED FORECAST. A TROUGH WILL DEVELOP THROUGH THE
OHIO VALLEY INITIALLY AS ENERGY FROM THE NORTHERN PLAINS POOLS OVER
THE REGION. THIS TROUGH EVOLVES GRADUALLY AS A COUPLE OF CYCLES
OF WAVES MOVE THROUGH THE OHIO VALLEY...EACH DEPICTED SLIGHTLY
DIFFERENT BY THE MODELS. THIS SEMI-STATIONARY TROUGH BOTTOMS OUT ON
THURSDAY PER A CONSENSUS OF SOLUTIONS. EACH MODEL HAS ENOUGH OF A
DIFFERENT HANDLING OF THE INDIVIDUAL WAVES THAT A BLENDED APPROACH
IS PREFERRED FOR EXTENDED FORECASTING PURPOSES. IT DOES LOOK LIKE
HEIGHTS WILL RISE A BIT ON FRIDAY AS THE CORE OF THE TROUGH SHIFTS
TEMPORARILY EAST BUT THE ECMWF IS MOST AGGRESSIVE IN TAKING ANOTHER
DECENT WAVE FROM THE PLAINS EAST INTO THE OHIO VALLEY FOR THE
WEEKEND LIKELY RESTORING THE TROUGH FOR THE OHIO VALLEY. THE GFS HAS
A VERSION OF THIS THAT ALSO LOWERS HEIGHTS OVER THE OHIO VALLEY ON
SATURDAY...BUT DOES SO BY RELYING ON WAVES FURTHER NORTH THAN THE
ECMWF...MAINLY MOVING THEM THROUGH THE GREAT LAKES. AGAIN HERE...
WILL FAVOR A CONSENSUS SOLUTION FOR WEATHER DETAILS.
SENSIBLE WEATHER WILL FEATURE A VERY UNSETTLED SITUATION TO START
THE EXTENDED AS MID LEVEL WAVES ACTIVATE SHOWERS AND THUNDERSTORMS
ALONG AND SOUTH OF A FRONTAL BOUNDARY RUNNING JUST NORTH OF THE OHIO
RIVER. THERE WILL BE PLENTY OF HIGH PW AIR IN PLACE TO SUPPORT THE
STORMS AND THUS A HEAVY RAIN POTENTIAL WILL EXIST THROUGH THE
DAY...MONDAY. THE NEXT SFC BOUNDARY WILL APPROACH THE AREA ON
TUESDAY CONTINUING OUR CHANCES OF SHOWERS AND THUNDERSTORMS. THIS
CONVECTION IS EXPECTED TO LINGER INTO THE NIGHT WHEN THE BOUNDARY
DROPS THROUGH THE CWA IN THE FORM OF A COLD FRONT. FOR THURSDAY AND
FRIDAY...ANY CONVECTION SHOULD BE AT A MINIMUM IN THE WAKE OF THE
SFC FRONT AND SLIGHTLY HIGHER HEIGHTS ALOFT. HOWEVER...THE NEXT SFC
SYSTEM LOOKS TO BRING A RENEWED CHANCE OF CONVECTION TO THE AREA ON
SATURDAY...SPURRED ON BY FALLING HEIGHTS AND MORE INBOUND MID-LEVEL
ENERGY.
THE CR GRID LOAD CAME IN PRETTY GOOD CONSIDERING THE SMALLER SCALE
DIFFERENCES AMONG THE MODELS WITH RESPECT TO WEATHER DETAILS THROUGH
THE EXTENDED. DID NUDGE DOWN POPS A BIT LATE IN THE FORECAST...MORE
TOWARD THE OPERATIONAL ECMWF. ALSO...ADJUSTED OVERNIGHT LOWS A TAD
FOR WEDNESDAY AND THURSDAY NIGHT TO BETTER EMPHASIZE RIDGE AND
VALLEY TEMPERATURE DIFFERENCES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 123 PM EDT SAT JUL 20 2013
A WEAK COLD FRONT WILL PUSH SOUTHEAST AND STALL OVER EASTERN KENTUCKY
THIS EVENING AND TONIGHT. A COMPLEX OF SHOWERS AND STORMS WILL PUSH
SOUTH THIS EVENING REACHING EASTERN KENTUCKY BETWEEN 23Z AND 02Z. AT
THIS TIME...SOME QUESTION AS TO IF IT WILL HOLD TOGETHER TO IMPACT
THE TAF SITES. THUS...GOING TO GO WITH A VCTS FOR NOW TO COVER THIS
THREAT. WITH THE FRONTAL BOUNDARY STALLED OVER THE AREA...SHOWERS
WILL REMAIN POSSIBLE THROUGH TONIGHT AND TOMORROW. COVERAGE SHOULD
INCREASE AS WE HEAD THROUGH THE DAY TOMORROW...BUT STILL LOW
CONFIDENCE ON IF AND WHEN TAF SITES ARE IMPACTED. THUS...GOING TO
MAINTAIN THE VCSH/VCTS. OTHERWISE...LIGHT SOUTHWEST WINDS WILL
CONTINUE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JMW
SHORT TERM...KAS
LONG TERM...GREIF
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
325 PM EDT SAT JUL 20 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 325 PM EDT SAT JUL 20 2013
CONTINUING TO WATCH SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS
DROPPING SOUTHWARD ACROSS THE OHIO RIVER VALLEY. A GAP IN THE LINE
HAS OPENED UP JUST TO OUR NORTH. WHILE SHOWERS AND STORMS ARE STILL
POSSIBLE THIS EVENING INTO TONIGHT...EVERY HRRR RUN OVER THE PAST
SEVERAL HOURS CONTINUES TO BACK OFF ON OVERALL COVERAGE ACROSS
EASTERN KENTUCKY THIS EVENING...WITH EVERYTHING FADING AWAY AROUND
SUNSET. THUS...HAVE DECREASED POPS INTO THIS EVENING AND THE
OVERNIGHT HOURS. THIS TREND MAY HAVE TO BE CONTINUED ON THE EVENING
SHIFT IF THE TRENDS CONTINUE THE WAY THEY ARE HEADING.
REGARDLESS...THE PROSPECTS FOR WIDESPREAD SHOWERS AND THUNDERSTORMS
IS DRASTICALLY LESS NOW. WILL MAINTAIN LOW 20-30 POPS THROUGH THE
OVERNIGHT HOURS. WITH THE BOUNDARY WASHED OUT OVER THE AREA
TOMORROW...DAYTIME HEATING SHOULD ALLOW FOR QUICK REDEVELOPMENT AFTER
SUNRISE. COVERAGE SHOULD BE DECENT TOMORROW...SO OPTED TO STAY WITH
OUR 60-70 POPS. THERE IS SOME QUESTION AS TO HOW MUCH ACTIVITY WILL
THEN LINGER INTO TOMORROW NIGHT AS THE QUASI BOUNDARY MAY SHIFT BACK
TO THE NORTH. LACK OF OVERNIGHT INSTABILITY MAY KEEP THINGS FAIRLY
LOW KEY FOR MUCH OF THE NIGHT. THERE IS A SHORTWAVE TROUGH PUSHING
ACROSS THE AREA LATE IN THE NIGHT THAT COULD ACT TO FIRE OFF SOME
SHOWERS AND THUNDERSTORMS...SO WILL INCREASE POPS THROUGH THE NIGHT.
TEMPERATURES ON SUNDAY SHOULD BE SLIGHTLY LOWER WITH THE INCREASED
CLOUD COVER AND PRECIPITATION.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 325 PM EDT SAT JUL 20 2013
THE MODELS BASICALLY AGREE ON THE GENERAL MID LEVEL PATTERN THROUGH
THE BULK OF THE EXTENDED FORECAST. A TROUGH WILL DEVELOP THROUGH THE
OHIO VALLEY INITIALLY AS ENERGY FROM THE NORTHERN PLAINS POOLS OVER
THE REGION. THIS TROUGH EVOLVES GRADUALLY AS A COUPLE OF CYCLES
OF WAVES MOVE THROUGH THE OHIO VALLEY...EACH DEPICTED SLIGHTLY
DIFFERENT BY THE MODELS. THIS SEMI-STATIONARY TROUGH BOTTOMS OUT ON
THURSDAY PER A CONSENSUS OF SOLUTIONS. EACH MODEL HAS ENOUGH OF A
DIFFERENT HANDLING OF THE INDIVIDUAL WAVES THAT A BLENDED APPROACH
IS PREFERRED FOR EXTENDED FORECASTING PURPOSES. IT DOES LOOK LIKE
HEIGHTS WILL RISE A BIT ON FRIDAY AS THE CORE OF THE TROUGH SHIFTS
TEMPORARILY EAST BUT THE ECMWF IS MOST AGGRESSIVE IN TAKING ANOTHER
DECENT WAVE FROM THE PLAINS EAST INTO THE OHIO VALLEY FOR THE
WEEKEND LIKELY RESTORING THE TROUGH FOR THE OHIO VALLEY. THE GFS HAS
A VERSION OF THIS THAT ALSO LOWERS HEIGHTS OVER THE OHIO VALLEY ON
SATURDAY...BUT DOES SO BY RELYING ON WAVES FURTHER NORTH THAN THE
ECMWF...MAINLY MOVING THEM THROUGH THE GREAT LAKES. AGAIN HERE...
WILL FAVOR A CONSENSUS SOLUTION FOR WEATHER DETAILS.
SENSIBLE WEATHER WILL FEATURE A VERY UNSETTLED SITUATION TO START
THE EXTENDED AS MID LEVEL WAVES ACTIVATE SHOWERS AND THUNDERSTORMS
ALONG AND SOUTH OF A FRONTAL BOUNDARY RUNNING JUST NORTH OF THE OHIO
RIVER. THERE WILL BE PLENTY OF HIGH PW AIR IN PLACE TO SUPPORT THE
STORMS AND THUS A HEAVY RAIN POTENTIAL WILL EXIST THROUGH THE
DAY...MONDAY. THE NEXT SFC BOUNDARY WILL APPROACH THE AREA ON
TUESDAY CONTINUING OUR CHANCES OF SHOWERS AND THUNDERSTORMS. THIS
CONVECTION IS EXPECTED TO LINGER INTO THE NIGHT WHEN THE BOUNDARY
DROPS THROUGH THE CWA IN THE FORM OF A COLD FRONT. FOR THURSDAY AND
FRIDAY...ANY CONVECTION SHOULD BE AT A MINIMUM IN THE WAKE OF THE
SFC FRONT AND SLIGHTLY HIGHER HEIGHTS ALOFT. HOWEVER...THE NEXT SFC
SYSTEM LOOKS TO BRING A RENEWED CHANCE OF CONVECTION TO THE AREA ON
SATURDAY...SPURRED ON BY FALLING HEIGHTS AND MORE INBOUND MID-LEVEL
ENERGY.
THE CR GRID LOAD CAME IN PRETTY GOOD CONSIDERING THE SMALLER SCALE
DIFFERENCES AMONG THE MODELS WITH RESPECT TO WEATHER DETAILS THROUGH
THE EXTENDED. DID NUDGE DOWN POPS A BIT LATE IN THE FORECAST...MORE
TOWARD THE OPERATIONAL ECMWF. ALSO...ADJUSTED OVERNIGHT LOWS A TAD
FOR WEDNESDAY AND THURSDAY NIGHT TO BETTER EMPHASIZE RIDGE AND
VALLEY TEMPERATURE DIFFERENCES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 123 PM EDT SAT JUL 20 2013
A WEAK COLD FRONT WILL PUSH SOUTHEAST AND STALL OVER EASTERN KENTUCKY
THIS EVENING AND TONIGHT. A COMPLEX OF SHOWERS AND STORMS WILL PUSH
SOUTH THIS EVENING REACHING EASTERN KENTUCKY BETWEEN 23Z AND 02Z. AT
THIS TIME...SOME QUESTION AS TO IF IT WILL HOLD TOGETHER TO IMPACT
THE TAF SITES. THUS...GOING TO GO WITH A VCTS FOR NOW TO COVER THIS
THREAT. WITH THE FRONTAL BOUNDARY STALLED OVER THE AREA...SHOWERS
WILL REMAIN POSSIBLE THROUGH TONIGHT AND TOMORROW. COVERAGE SHOULD
INCREASE AS WE HEAD THROUGH THE DAY TOMORROW...BUT STILL LOW
CONFIDENCE ON IF AND WHEN TAF SITES ARE IMPACTED. THUS...GOING TO
MAINTAIN THE VCSH/VCTS. OTHERWISE...LIGHT SOUTHWEST WINDS WILL
CONTINUE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...KAS
LONG TERM...GREIF
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS PADUCAH KY
200 PM CDT SAT JUL 20 2013
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
ISSUED AT 200 PM CDT SAT JUL 20 2013
18Z MESOANALYSIS SHOWS A COLD FRONT EXTENDING WESTWARD ACROSS
CENTRAL INDIANA TO A WEAK SURFACE LOW OVER CENTRAL ILLINOIS. A
SURFACE TROUGH EXTENDS SOUTHWEST FROM THE LOW CENTER TO NEAR KFAM
AND THEN BETWEEN KUNO/KPOF. DEW POINTS POOLING INTO THE LOWER AND
MID 70S ALONG THE TROUGH AND COLD FRONT HAVE CONTRIBUTED TO VERY
UNSTABLE CAPES LOCALLY OVER 3000 J/KG. ISOLATED STORMS HAVE POPPED
UP ALONG THE SURFACE TROUGH OVER MISSOURI...WHILE LARGER CLUSTERS OF
STORMS ARE EAST OF THE SURFACE LOW CENTER IN INDIANA/EAST CENTRAL IL.
THROUGH THE EVENING HOURS...THE COLD FRONT IS FORECAST TO DRIFT
SOUTH TO THE INTERSTATE 64 CORRIDOR WHILE THE SURFACE TROUGH REMAINS
STATIONARY OVER THE MISSOURI OZARKS. THE LATEST HRRR MODEL
REFLECTIVITY INDICATES THAT CLUSTERS OF STORMS /POSSIBLE MCS/ WILL
PROPAGATE SOUTH ALONG THE WABASH VALLEY...REACHING THE PENNYRILE
REGION OF WESTERN KY THIS EVENING. THIS SCENARIO IS SUPPORTED BY THE
12Z HIGH RES NMM. OTHER ISOLATED STORMS MAY DEVELOP EASTWARD FROM
THE SURFACE TROUGH OVER MISSOURI. VERY LIMITED SHEAR MAGNITUDE WILL
LIMIT SEVERE POTENTIAL TO ISOLATED PULSE EVENTS...THOUGH AN
ORGANIZED COLD POOL COULD DEVELOP WITH THE WABASH VALLEY MCS.
ACTIVITY WILL WEAKEN SIGNIFICANTLY BY 06Z AS THE BOUNDARY LAYER
COOLS AND STABILIZES.
ON SUNDAY...THE SURFACE FRONT IS FORECAST TO SLOWLY LIFT BACK NORTH
AS A WARM FRONT. A MINOR 500 MB SHORTWAVE WILL MOVE EAST/SOUTHEAST
ACROSS THE MISSISSIPPI VALLEY. THIS SHORTWAVE WILL HELP REJUVENATE
CONVECTION ALONG AND SOUTH OF THE FRONT...ESPECIALLY DURING THE
WARMER AND MORE UNSTABLE AFTERNOON HOURS. HIGH TEMPS WILL STRUGGLE
TO REACH THE UPPER 80S DUE TO ABUNDANT CLOUDINESS AND CONVECTION.
ON SUNDAY NIGHT...A RATHER WELL DEVELOPED 500 MB SHORTWAVE FOR MID
SUMMER WILL APPROACH FROM THE CENTRAL PLAINS. THIS SHORTWAVE WILL
TAP A VERY MOIST AND UNSTABLE SOUTHWEST WIND FLOW. SHOWERS AND
STORMS ARE LIKELY OVERNIGHT INTO MONDAY MORNING...UNTIL THE PASSAGE
OF THE SHORTWAVE. ONCE AGAIN...SEASONABLY WEAK SHEAR PROFILES WILL
LIMIT THE POTENTIAL HAZARDS TO MAINLY HEAVY RAIN AND FREQUENT
LIGHTNING.
ON MONDAY AFTERNOON AND MONDAY NIGHT...PRECIP COVERAGE WILL
GRADUALLY DECREASE WITH THE PASSAGE OF THE SHORTWAVE. 850 MB WARM
ADVECTION WILL BE COUNTERED BY EXTENSIVE CLOUD COVER AND PRECIP...
SO DAYTIME HIGHS ON MONDAY WILL ONLY BE NEAR SEASONAL NORMS.
OVERNIGHT LOWS WILL BE NEAR SURFACE DEW POINTS IN THE LOWER 70S.
.LONG TERM /TUESDAY THROUGH SATURDAY/...
ISSUED AT 200 PM CDT SAT JUL 20 2013
THE MODELS ARE IN A LITTLE BETTER AGREEMENT WITH THE TIMING OF THE
MID WEEK FRONT. THIS FRONT WILL PROVIDE THE FOCUS FOR THUNDERSTORMS
TUESDAY THEN TAPERING OFF INTO WEDNESDAY. WEAK HIGH PRESSURE WILL
DRY US OUT FOR AT LEAST THURSDAY AND FRIDAY WITH AT LEAST A CHANCE
RETURNING FRIDAY NIGHT INTO SATURDAY AS YET ANOTHER COLD FRONT
ENTERS THE PICTURE AT THE SAME TIME A WARM FRONT TRIES TO LIFT OUT
OF THE PLAINS INTO THE REGION. THE LATEST RUNS WOULD HAVE THE COLD
FRONT WINNING OUT AND SUPPRESSING THE WARM FRONT TO THE SOUTHWEST.
HOWEVER...THE SIGNALS ARE VERY WEAK AND MAY FLIP FLOP WITH LATER
RUNS. THIS WOULD ALSO RESULT IN A SIGNIFICANT CHANGE FOR TEMPS THIS
WEEKEND. EITHER WAY ONE SYSTEM OR THE OTHER WILL PROVIDE A CHANCE
FOR THUNDERSTORMS.
AS FOR TEMPS FOLLOWED THE ONGOING TREND WITH THE WARMEST DAY TUESDAY
THEN COOLING AND A BIT DRIER LATE IN THE WEEK. TEMPS BEGIN TO SOAR
BACK TO AROUND 90 LATE IN THE WEEK AHEAD OF THE APPROACHING COLD
FRONT. IF THE WEEKEND COLD FRONT MAKES IT THROUGH THE AREA WE WILL
COOL BACK INTO THE 80S AGAIN HOWEVER SHOULD THE WARM FRONT OVERTAKE
THE REGION WILL HAVE TO ADJUST TEMPS UP FROM CURRENT FORECAST.
&&
.AVIATION...
ISSUED AT 1226 PM CDT SAT JUL 20 2013
A WEAK COLD FRONT WAS IN THE VICINITY OF KSTL/KIND LINE AT 17Z. THIS
FRONT WILL SINK SLOWLY SOUTH...POSSIBLY BRINGING ISOLATED TO
SCATTERED THUNDERSTORMS TO THE TAF SITES THIS EVENING. CONVECTION
SHOULD WEAKEN OR DISSIPATE WITH LOSS OF DAYTIME HEATING BY 06Z.
WINDS WILL BECOME LIGHT AND VARIABLE OVERNIGHT...ALLOWING SOME LIGHT
FOG OR HAZE TO FORM AS SKIES BECOME MOSTLY CLEAR. MID LEVEL CLOUDS
WILL INCREASE AHEAD OF AN UPPER LEVEL DISTURBANCE EARLY SUNDAY.
SCATTERED SHOWERS MAY DEVELOP AFTER SUNRISE AS THE FRONT BEGINS TO
MOVE BACK NORTH AS A WARM FRONT.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
SHORT TERM...MY
LONG TERM...KH
AVIATION...MY
AREA FORECAST DISCUSSION
NWS JACKSON KY
123 PM EDT SAT JUL 20 2013
.UPDATE...
ISSUED AT 123 PM EDT SAT JUL 20 2013
WATCHING A COUPLE COMPLEXES OF SHOWERS AND THUNDERSTORMS OFF TO THE
NORTH. THE FIRST ONE JUST WENT THROUGH THE INDIANAPOLIS AREA...WITH
THE SECOND ONE JUST THROUGH DAYTON. THE ONE THAT CONCERNS EASTERN
KENTUCKY IS THE COMPLEX IN INDIANA. BASED ON TRENDS...THIS COMPLEX
SHOULD REACH NORTHERN FLEMING COUNTY AROUND 23Z. THERE WAS A WIND
GUST AT THE INDIANAPOLIS AIRPORT TO 36 KNOTS...SO THERE IS SOME LOW
END POTENTIAL FOR SOME STRONG WIND GUSTS AS THIS STUFF PUSHES
SOUTHEAST THIS EVENING. SPC HAS ISSUED A WATCH JUST TO OUR NORTH.
FORTUNATELY THE SHEAR IS VERY WEAK AND GETTING MORE WIDESPREAD
DAMAGING WINDS SEEMS VERY LOW AT THIS TIME. OTHER ISOLATED SHOWERS
AND EVEN A THUNDERSTORM HAVE DEVELOPED ACROSS EASTERN KENTUCKY. MOST
OF THESE SHOWERS HAVE BEEN SHORT LIVED AND FEW AND FAR BETWEEN.
OUTSIDE OF A SOME SPORADIC LIGHTNING OR A BRIEF PERIOD OF HEAVY
RAIN...THESE SHOWERS SHOULD POSE VERY LITTLE THREAT TO THE AREA THIS
AFTERNOON.
UPDATE ISSUED AT 923 AM EDT SAT JUL 20 2013
BAND OF ENHANCED CU IS PUSHING SOUTHEAST...EXTENDING FROM NEAR
DANVILLE TO WEST LIBERTY THIS MORNING. BASED ON INITIAL ANALYSIS THIS
MORNING...THIS MAY HELP TO GENERATE SOME ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS HEADING INTO THE AFTERNOON HOURS.
HOWEVER...THIS ACTIVITY WILL LIKELY SHIFT SOUTHEAST AS WE HEAD INTO
THE LATE AFTERNOON HOURS AS SUBSIDENCE AHEAD OF THE APPROACHING COLD
FRONT FROM THE NORTH OVERSPREADS THE AREA. LATEST HRRR TAKES MOST OF
THE DAY TO GET ANY PRECIPITATION AS FAR SOUTH AS FLEMING COUNTY
(LIKELY NOT UNTIL AFTER 22 OR 23Z). THUS...GOING TO BACK OFF ON THE
HIGHER PRECIPITATION CHANCES TODAY...BUT STILL CARRY SOME ISOLATED
COVERAGE ACROSS THE SOUTHEAST ASSOCIATED WITH THE BAND OF ENHANCED
CU AS IT DROPS SOUTHEAST. OTHERWISE...WILL GO WITH HIGHER POPS NORTH
OF I-64 AFTER 22Z. SOME QUESTION AS TO HOW MUCH ACTIVITY LINGERS INTO
TONIGHT AS THE FRONT WASHES OUT OVER THE AREA. WILL DROP POPS BACK
FOR THE OVERNIGHT HOURS AS COVERAGE WILL LIKELY REMAIN MORE ISOLATED
TO SCATTERED ALONG THE BOUNDARY SINCE IT WILL BE HARD TO SEE MUCH
ORGANIZED ACTIVITY ALONG THE STALLED BOUNDARY. UPDATE WILL BE OUR
SHORTLY.
UPDATE ISSUED AT 705 AM EDT SAT JUL 20 2013
INGESTED THE MOST CURRENT OBSERVATION DATA TO ESTABLISH NEW TRENDS IN
THE FORECAST GRIDS. THE FORECAST WAS ON TRACK OVERALL...ALTHOUGH THE
FOG THAT WAS FORECAST TO FORM OVERNIGHT WAS NOT NEARLY AS EXTENSIVE
AS ORIGINAL THINKING INDICATED. WITH THE FORECAST IN PRETTY GOOD
SHAPE OVERALL...NO UPDATE IS PLANNED AT THIS TIME.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 313 AM EDT SAT JUL 20 2013
MODELS IN PRETTY GOOD AGREEMENT WITH THE OVERALL LARGE SCALE
WEATHER PATTERN AND SENSIBLE WEATHER FOR THE NEXT COUPLE OF DAYS. A
WARM AND HUMID AIR MASS WILL REMAIN IN PLACE ACROSS EASTERN KENTUCKY
TODAY AND TOMORROW...AS SOUTHERLY FLOW PERSISTS AHEAD OF A SLOWLY
APPROACHING COLD FRONT. THE WEATHER TODAY SHOULD START OUT QUIET...AS
THE LACK OF A GOOD TRIGGER FOR CONVECTION SHOULD KEEP SHOWER AND
STORM ACTIVITY TO A MINIMUM THROUGH EARLY THIS AFTERNOON. SHOWERS AND
STORMS WILL GRADUALLY INCREASE IN COVERAGE BEGINNING MID AFTERNOON
TODAY...AS THE COLD FRONT FINALLY BEGINS MAKING ITS SOUTHWARD PUSH.
THE BEST CHANCE FOR RAIN WILL BEGIN EARLY THIS EVENING NORTH OF THE
MOUNTAIN PARKWAY. THE FRONT IS THEN PROGGED TO SAG SOUTHWARD OUT OF
THE OHIO VALLEY AND ACROSS CENTRAL AND EASTERN KENTUCKY OVERNIGHT
TONIGHT. ONCE LOSS OF DAYTIME HEATING BEGINS TO OCCUR...ANY SHOWERS
AND STORMS WILL DECREASE IN COVERAGE...WITH ONLY SCATTERED SHOWERS
AND ISOLATED STORMS EXPECTED DURING THE NIGHT TIME HOURS. ONCE THE
SUN HAS A BEEN UP FOR AWHILE ON SUNDAY...THE FRONT WILL BECOME ACTIVE
ONCE AGAIN...WITH NUMEROUS SHOWERS AND STORMS EXPECTED ACROSS THE
AREA FROM LATE SUNDAY MORNING THROUGH THE END OF THE DAY ON SUNDAY.
DUE TO SLUGGISH MIDDLE AND UPPER LEVEL WINDS...ANY SHOWERS AND STORMS
THAT FORM WILL BE VERY SLOW MOVING...WHICH COULD LEAD TO LOCALIZED
HEAVY RAIN AND POSSIBLY MINOR FLOODING ISSUES.
TEMPERATURES WILL BE QUITE HOT ONCE AGAIN TODAY...BUT WITH THE GROUND
STILL BEING SOMEWHAT MOIST FROM RECENT RAINFALL...AND WITH AREA
VEGETATION IN FULL LEAF...90 DEGREE READINGS WILL BE DIFFICULT TO
COME BY. WITH THAT IN MIND...LOWERED TODAYS HIGH TEMPERATURES ACROSS
THE BOARD TO REFLECT THIS. WILL LIKELY SEE READINGS TOP OUT MOSTLY IN
THE UPPER 80S AREA WIDE...WITH ISOLATED OCCURRENCES OF 90 HERE AND
THERE. HIGHS ON SUNDAY WILL LIKELY RUN SLIGHTLY BELOW NORMAL...DUE TO
SHOWER AND STORM ACTIVITY AND THE PASSAGE OF THE COLD FRONT. HIGHS ON
SUNDAY ARE EXPECTED TO TOP OUT IN THE LOWER 80S. OVERNIGHT LOWS WILL
BOTTOM OUT AROUND A BALMY 70 DEGREES. WINDS WILL REMAIN FAIRLY LIGHT
ACROSS THE AREA TODAY AND TOMORROW.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 313 AM EDT SAT JUL 20 2013
THE SYNOPTIC PATTERN OVER THE EASTERN U.S. NEXT WEEK WILL FEATURE
THE DEVELOPMENT OF AN UPPER LEVEL TROUGH EARLY IN THE WEEK WITH A
LEAD SHORTWAVE TRAVERSING THE OHIO VALLEY MONDAY AND MONDAY NIGHT.
OUR FORECAST WILL FEATURE THE HIGHEST RAIN CHANCES WITH THIS LEAD
SHORTWAVE ACTING AS THE FOCUS FOR SHOWERS AND THUNDERSTORMS MONDAY
AND MONDAY NIGHT. THIS FEATURE WILL PASS BY BUT THE UPPER LEVEL
TROUGH IS PROGGED TO HANG OUT WITH IT/S AXIS ALIGNED DOWN THE
APPALACHIAN CHAIN THROUGH AT LEAST FRIDAY...WITH SIGNS IN THE
MODELING THAT IT WILL GET REINFORCED NEXT WEEKEND. THIS SPELLS A
CONTINUATION OF UNSETTLED WEATHER WITH DAILY SHOWER AND THUNDERSTORM
CHANCES. A COLD FRONT WILL SLOWLY DROP THROUGH THE OHIO VALLEY
MIDWEEK RESULTING IN SCATTERED SHOWERS/STORMS...ESPECIALLY DURING
THE AFTERNOON AND EARLY EVENING HOURS. THE FRONT IS PROGGED TO DROP
TO OUR SOUTH FINALLY BY LATE THURSDAY INTO FRIDAY WITH A WEAK AREA
OF HIGH PRESSURE SLIDING DOWN INTO THE REGION. TRENDED RAIN CHANCES
DOWNWARD FROM INHERITED NUMBERS THURSDAY AND FRIDAY...BUT DID NOT
REMOVE THEM TOTALLY JUST YET.
THE GOOD NEWS IS THAT TEMPERATURES AND DEWPOINTS WILL BE ON A
DOWNWARD TREND DURING THE PERIOD. TEMPS WILL SETTLE BACK TO MORE
NORMAL VALUES FOR THIS TIME OF YEAR...WITH HIGHS GENERALLY IN THE
LOW TO MID 80S EACH DAY. DEWPOINTS WILL REMAIN HIGH...AROUND
70...UNTIL THE COLD FRONT DROPS TO OUR SOUTH LATE IN THE WEEK. THIS
SHOULD DROP DEWS BACK INTO THE 60S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 123 PM EDT SAT JUL 20 2013
A WEAK COLD FRONT WILL PUSH SOUTHEAST AND STALL OVER EASTERN KENTUCKY
THIS EVENING AND TONIGHT. A COMPLEX OF SHOWERS AND STORMS WILL PUSH
SOUTH THIS EVENING REACHING EASTERN KENTUCKY BETWEEN 23Z AND 02Z. AT
THIS TIME...SOME QUESTION AS TO IF IT WILL HOLD TOGETHER TO IMPACT
THE TAF SITES. THUS...GOING TO GO WITH A VCTS FOR NOW TO COVER THIS
THREAT. WITH THE FRONTAL BOUNDARY STALLED OVER THE AREA...SHOWERS
WILL REMAIN POSSIBLE THROUGH TONIGHT AND TOMORROW. COVERAGE SHOULD
INCREASE AS WE HEAD THROUGH THE DAY TOMORROW...BUT STILL LOW
CONFIDENCE ON IF AND WHEN TAF SITES ARE IMPACTED. THUS...GOING TO
MAINTAIN THE VCSH/VCTS. OTHERWISE...LIGHT SOUTHWEST WINDS WILL
CONTINUE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...AR
LONG TERM...ABE
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS CARIBOU ME
310 PM EDT SAT JUL 20 2013
.SYNOPSIS...
A STRONG COLD FRONT WILL CROSS THE REGION TONIGHT. A DRIER AND
COOLER CANADIAN AIRMASS WILL THEN BUILD INTO THE AREA ON SUNDAY
AND HOLD OVER THE REGION THROUGH MONDAY. THE NEXT LOW PRESSURE
FROM THE GREAT LAKES WILL APPROACH THE REGION LATE MONDAY NIGHT
INTO TUESDAY.
&&
.NEAR TERM /THROUGH SUNDAY/...
A COLD FRONT WILL MOVE THROUGH THE REGION OVERNIGHT FOLLOWED BY
CANADIAN HIGH PRES FOR SUNDAY. THIS HIGH WILL REMAIN IN CONTROL
THROUGH EARLY NEXT WEEK.
SOME CONVECTION HAS FIRED UP MAINLY ACROSS NORTHERN AND WESTERN
AREAS(SUB-SEVERE) AS SOME UPPER LEVEL DIVERGENCE SEEN ON THE SATL
WV IMAGERY AND 12Z UA. THE BEST SHOT FOR ANY STRONGER STORMS WILL
BE ACROSS THE DOWNEAST AND COAST INTO THE EVENING AND THEN
ACTIVITY WILL WEAKEN. THE BEST FORCING AND INSTABILITY WILL SHIFT
TO THE EAST. ADDED SOME FOG TO THE GRIDS FOR TONIGHT INTO EARLY
SUNDAY MORNING BASED ON ANTICIPATED CLEARING AND COOLER TEMPERATURES
W/A WET GROUND. ADJUSTED THE OVERNIGHT LOW USING A BLEND OF THE NAM12
AND ECMWF. POPS ARE A BLEND OF THE RUC AND DOWNSCALED NAM WHICH
SHOW PRECIP CHANCES WINDING DOWN AFTER 00Z.
SUNDAY LOOKS TO BE SUNNY AND PLEASANT W/HIGH PRES BUILDING IN FROM
CANADA. THINKING ATTM IS TO TAKE W/CONSISTENCY AND KEEP THE
MIDNIGHT CREW`S MAXES OF LOWER 70S NORTHERN CWA AND MID TO UPPER
70S CENTRAL AND DOWNEAST.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
HIGH PRESSURE WILL SETTLE OVER THE AREA SUNDAY NIGHT. WITH LIGHT
WINDS...CLEAR SKIES AND RELATIVELY DRY AIR THE NIGHT WILL BE COOL
WITH LOWS DROPPING INTO THE 40S NORTH TO NEAR 50 DOWNEAST. THIS
WILL BE FOLLOWED BY A MOSTLY SUNNY AND SEASONABLE DAY ON MONDAY.
CLOUDS WILL BEGIN TO INCREASE FROM THE SOUTHWEST LATE IN THE DAY
AS MOISTURE LIFTS NORTH FROM LOW PRESSURE TRACKING INTO SOUTHERN
NEW ENGLAND. CLOUDS WILL CONTINUE TO INCREASE MONDAY NIGHT AND
SOME RAIN MAY SPREAD INTO THE AREA LATE. THE BEST CHANCE FOR RAIN
WILL BE ALONG THE FRONTAL BOUNDARY WHICH WILL BE NEAR THE COAST.
THE LOW WILL TRACK JUST OFFSHORE ON TUESDAY BRINGING A CHANCE OF
RAIN TO THE AREA. THE BEST CHANCE FOR RAIN WILL BE ALONG COASTAL
AREAS. A COLD FRONT WILL APPROACH THE WEST LATE IN THE DAY. WARM
AND HUMID AIR MOVING NORTH AHEAD OF THE FRONT BENEATH RELATIVELY
COOLER AIR ALOFT MAY PRODUCE SOME THUNDERSTORMS IN WESTERN AREAS
LATE IN THE DAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
A WEAK LOW WILL BE TRACKING OFF THE COAST TUESDAY NIGHT AS A COLD
FRONT APPROACHES FROM THE WEST. THE LOW MAY BRING SOME RAIN TO
COASTAL AREAS EARLY TUESDAY NIGHT WHILE THE APPROACHING FRONT
BRINGS SOME SHOWERS AND POSSIBLY THUNDERSTORMS TO FAR WESTERN
AREAS. THE FRONT IS EXPECTED TO CROSS THE AREA EARLY WEDNESDAY
BRINGING SOME SHOWERS AND ISOLATED THUNDERSTORMS MAINLY TO THE
DOWNEAST REGION. HIGH PRESSURE SHOULD THEN BRING DRIER AIR WITH
CLEARING LATER WEDNESDAY INTO THURSDAY. ANOTHER FRONT MAY APPROACH
LATER FRIDAY INTO SATURDAY WITH INCREASED HUMIDITY FRIDAY INTO
SATURDAY.
&&
.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: UNSETTLED CONDITIONS THROUGH AT THE START OF THE
PERIOD. MVFR NORTH...BECMG VFR EARLY EVENING. A BRIEF PERIOD OF
MVFR AND PERHAPS IFR FOR KBHB/KBGR THROUGH TONIGHT IN SHRA/TSRA
AND SOME FOG. VFR ALL SITES ON SUNDAY.
SHORT TERM: VFR CONDITIONS ARE EXPECTED SUNDAY NIGHT INTO MONDAY
WITH HIGH PRESSURE AND MOSTLY CLEAR SKIES. CONDITIONS WILL LIKELY
BEGIN VFR MONDAY NIGHT BUT MAY LOWER TO MVFR OR IFR LATE AS LOW
CLOUDS AND SHOWERS MOVE IN. MVFR CONDITIONS ARE EXPECTED TUESDAY
NIGHT INTO EARLY WEDNESDAY. HIGH PRESSURE MAY THEN BRING AN
IMPROVEMENT TO VFR WEDNESDAY INTO EARLY FRIDAY. LOWERING CLOUDS
AND SHOWERS MAY LOWER CONDITIONS TO MVFR FRIDAY NIGHT INTO
SATURDAY AS THE NEXT FRONT MOVES IN.
&&
.MARINE...
NEAR TERM: SEAS 3-5 FT ATTM. WAVE GUIDANCE INCLUDING THE SWAN
RUNNING TOO HIGH AS THE LATEST OBS SHOWED NO MORE THAN 4 FT(44027).
WINDS ARE EXPECTED TO BECOME GUSTY W/THE COLD FRONT TONIGHT W/SPEEDS
OF 25 KT BRIEFLY. THE WINDS WILL SUBSIDE ON SUNDAY DOWN TO 10 KT AS
HIGH PRES PUSHES E.
SHORT TERM: WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW SCA THIS
WEEKEND INTO EARLY NEXT WEEK. HIGH PRESSURE SHOULD BRING CLEAR AND
PLEASANT CONDITIONS SUNDAY INTO MONDAY. LOWER CLOUDS...FOG AND
SOME RAIN MAY MOVE OVER THE WATERS ON TUESDAY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...NORTON/HEWITT
SHORT TERM...BLOOMER
LONG TERM...BLOOMER
AVIATION...NORTON/HEWITT/BLOOMER
MARINE...NORTON/BLOOMER
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
422 PM EDT SAT JUL 20 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 419 PM EDT SAT JUL 20 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL LOW OVER NE
CANADA AND A WEAK RIDGE INTO MANITOBA RESULTING IN CONFLUENT WNW
FLOW THROUGH THE NRN GREAT LAKES. AT THE SFC...A RIDGE EXTENDED FROM
SRN MANTIOBA INTO NW ONTARIO TO NW LAKE SUPERIOR. ABUNDANT DIRUNAL
CU HAD DEVELOPED IN THE COOL AIR TO THE NORTH OF LAKE SUPERIOR WHERE
850 MB TEMPS WERE DOWN TO 2C-3C. FARTHER SOUTH...VIS LOOP SHOWED
ONLY SCT CU OVER THE W HALF OF UPPER MI.
TONIGHT...WITH CLEAR SKIES AND LIGHT WINDS TONIGHT...FAVORABLE
RADIATIONAL COOLING CONDITIONS IN THE DRY AIRMASS OVER THE REGION
(PWAT BELOW 0.50 INCH)WILL ALLOW TEMPS TO DROP TO NEAR THE LOW END
OF GUIDANCE...NEAR 40 OVER THE COLDER INLAND LOCATIONS.
SUN...AS THE SFC HIGH SHIFTS EAST OF THE AREA AND THE MID LEVEL
FLOW BECOMES MORE ZONAL...SRLY FLOW AND WAA WILL INCREASE AHEAD OF
APPROACHING SHORTWAVE AND FRONTAL SYSTEM OVER THE NRN PLAINS. TEMPS
SHOULD CLIMB INTO THE LOWER TO MID 70S INLAND WITH LOWER READINGS IN
THE MID TO UPPER 60S ALONG THE GREAT LAKES. MODELS SUGGEST THAT THE
GREATEST INCREASE IN MOISTURE AND STRONGER 300-310K ISENTROPIC LIFT
WILL REMAIN TO THE SOUTH AND WEST OF UPPER MI FROM SRN MN INTO
CNTRL WI LATE SUN AFTERNOON. SO...THE FCST MAINTAINS ONLY SLIGHT
CHANCE POPS INTO THE FAR WEST
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 419 PM EDT SAT JUL 20 2013
UPPER AIR PATTERN THROUGH NEXT WEEK DRIVEN BY TWO AREAS OF LOWER
HEIGHTS...ONE OVER GULF OF ALASKA/BRITISH COLUMBIA AND THE OTHER
VCNTY OF HUDSON BAY ACROSS QUEBEC. IN BTWN THESE TWO...WNW FLOW
HOLDS IN PLACE FROM WESTERN CANADA ACROSS GREAT LAKES. MOST
PERSISTENT RIDGING WILL BE LIMITED TO SOUTHWEST PART OF CONUS.
PATTERN DOES NOT LOOK APPRECIABLY WARM...ESPECIALLY COMPARED TO
THE RECENT HEAT WAVE THAT AFFECTED GREAT LAKES REGION. OVERALL
TEMPS THROUGH THE PERIOD WILL BE AT OR SLIGHTLY BLO NORMAL /NORMAL
HIGH TEMPS ON AVERAGE THIS TIME OF YEAR ARE IN THE UPR 70S NORTH TO
LOWER 80S SOUTH/. WARMEST DAY MOST LIKELY ON MONDAY AS WARM FRONT
LIFTS ACROSS UPPER LAKES RESULTING IN SW SFC WINDS. COLD FRONT
MOVES IN MONDAY NIGHT THOUGH...MAKING THIS STAY IN THE WARM SECTOR
VERY BRIEF. SHRA/TSRA POSSIBLE AS THESE FRONTAL BOUNDARIES AFFECT
THE AREA. ONLY OTHER CHANCE OF RAIN ARRIVES LATER THURSDAY INTO
FRIDAY AS ANOTHER SFC TROUGH CROSSES THE REGION. WEAK HIGH PRESSURE
AND DRY WEATHER WILL DOMINATE THE WEATHER PATTERN REST OF THE LONG
TERM.
FIRST FOCUS IN LONGER TERM IS SHORTWAVE PRESSING INTO SCNTRL CANADA
ON SUNDAY NIGHT AND SFC LOW/TROUGH MOVING ACROSS NORTHERN PLAINS.
SLIGHT H85 TEMP/MOISTURE ADVECTION OVER UPR MICHIGAN AHEAD OF THE
WAVE AND SFC TROUGH...BUT INSTABILITY IS PRETTY MINIMAL WITH MUCAPES
1-6KM A FEW HUNDRED J/KG AT BEST...MAINLY OVER FAR WEST LK SUPERIOR
CLOSER TO STRONGEST H85-H7 MOISTURE TRANSPORT. FCST SOUNDINGS SHOW
INCREASE OF H8-H7 MOISTURE BUT HINT AT DRY AIR BLO AND ABOVE THIS
LAYER. WITH LACK OF INSTABILITY AND DEEP MOISTURE AND LARGER SCALE
FORCING...THINK COVERAGE TO ANY SHRA/TSRA WILL BE LIMITED SUN NIGHT
BUT CANNOT COMPLETELY RULE IT OUT.
SEEMS THAT BETTER CHANCES FOR SHRA/TSRA OCCUR ON MONDAY IN THE
MORNING DUE TO CLOSER PROXIMITY OF SHORTWAVE/H85 TROUGH AND
RESULTING SHARPER WARM AIR ADVECTION AND INCREASING H85 MOISTURE
TRANSPORT. EXPECT THIS WARM AIR ADVECTION SHRA/ISOLD TSRA TO SHIFT
NORTH BY AFTN ALONG SFC WARM FRONT AND THEN...PROVIDED THERE IS
ENOUGH CLEARING OF MORNING CLOUDS/SHRA/TSRA...THERE SHOULD BE PERIOD
OF BUILDING INSTABILITY DURING PEAK HEATING AS TEMPS WARM INTO THE
UPR 70S/LWR 80S. MLCAPES TOP OUT AROUND 800-1200J/KG...HIGHEST
ALONG WI BORDER. DEEP LAYER SHEAR INCREASES IN WARM SECTOR OUT
AHEAD OF COLD FRONT TO 30-40 KTS AS SHORTWAVE CROSSES NORTHERN
ONTARIO AND ADJACENT LK SUPERIOR. SOUNDINGS SHOW A BIT OF CAPPING
AROUND H8 AND THIS ADDS UNCERTAINTY TO INITIATION. BASED ON CAPE AND
SHEAR BALANCE...THERE SEEMS TO BE AT LEAST SMALL POTENTIAL FOR ISOLD
SVR STORMS. SUPERCELLS POSSIBLE AS WINDS SHOW SUFFICIENT VEERING WITH
HEIGHT. HAIL/WIND PRIMARY HAZARDS WITH LOWER WBZERO HEIGHTS AROUND
11KFT AND DCAPE UP TO 1000J/KG. ALL THIS IS CONDITIONAL ON HOW MUCH
INSTABILITY CAN MATERIALIZE. SINCE SPC DAY 3 DID INDICATE SEE TEXT
OVER THE AREA...THINK IT IS WORTH AN HWO MENTION.
COLD FRONT BLOWS THROUGH CWA PRETTY QUICKLY MONDAY EVENING/EARLY
OVERNIGHT. TRENDED TOWARD LOWER POPS 6Z-12Z ON TUESDAY WITH DRYING
NOTED IN SOUNDINGS AND GFS/ECMWF SHOWING LITTLE IF ANY QPF IN THAT
TIME FRAME THE LAST FEW MODEL RUNS. IN WAKE OF THE COLD FRONT ON
TUESDAY...COULD END UP WITH NEARLY CARBON COPY OF TODAY...COOL TEMPS
ALONG LK SUPERIOR/HIGHER SWIM RISK AND READINGS INTO LOWER 70S TOWARD
WI BORDER. CUT GUIDANCE TEMPS FOR TUESDAY NIGHT WITH HIGH CENTER
OVERHEAD. FAVORED COLD SPOTS OVER MAINLY WEST COULD REACH TO AROUND
40 DEGREES. STAYS QUIET THROUGH WEDNESDAY NIGHT AS HIGH PRESSURE
SLOWLY RETREATS.
NEXT CHANCE OF RAIN RETURNS THURSDAY INTO FRIDAY. MODELS HAVING
TOUGH TIME HANDLING SHORTWAVE TROUGH PUSHING THROUGH IN WNW FLOW
ALOFT. LATEST GFS AND ECMWF WOULD INDICATE SHORTWAVE PASSAGE
THURSDAY OR THURSDAY NIGHT. BLEND OF CONSENSUS SHOWS SLIGHT
CHANCE/LOW CHANCE POPS AS ANOTHER COLD FRONT CROSSES THE AREA
TIED TO THE WAVE. SATURDAY LOOKING PRETTY COOL YET AGAIN BEHIND
THIS COLD FRONT. PROBABLY WILL END UP SIMILAR TO WHAT IS OCCURRING
TODAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 139 PM EDT SAT JUL 20 2013
VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD AS HIGH
PRESSURE GRADUALLY BUILDS INTO THE REGION. NRLY WINDS WILL DIMINISH
THIS EVENING WITH THE LOSS OF DAYTIME HEATING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 419 PM EDT SAT JUL 20 2013
AS HIGH PRESSURE BUILDS INTO THE NORTHERN GREAT LAKES...WINDS WILL
DIMINISH THIS EVENING TO LESS THAN 20 KNOTS. SRLY WINDS WILL
INCREASE TO AROUND 20 KNOTS AHEAD OF A LOW PRESSURE TROUGH MOVING
THROUGH THE AREA ON MONDAY. NORTH TO NORTHWEST WINDS WILL THEN INCREASE
TO 20 TO 30 KNOTS BY LATE MONDAY NIGHT INTO TUESDAY BEHIND A COLD
FRONT MOVING THROUGH THE REGION. WINDS ARE THEN EXPECTED TO REMAIN
BELOW 20 KNOTS THROUGH THURSDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION...UPDATED
NWS GLASGOW MT
422 PM MDT SAT JUL 20 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH MONDAY...
MADE A QUICK UPDATE TO CHANGE AFTERNOON WX TO COVERAGE AND
INCREASE POPS. A COUPLE OF STRONG STORMS HAVE POPPED UP WITH
REPORTS OF HEAVY RAIN...SMALL HAIL...AND GUSTY WIND. SCT
PREVIOUS DISCUSSION...
CONVECTIVE ACTIVITY THIS AFTERNOON WILL CONTINUE TO DEVELOP OVER
THE NEXT COUPLE OF HOURS BUT SHOULD DIMINISH PRETTY QUICK WITHOUT
THE SHEAR IN PLACE. HRRR MODEL SHOWING JUST SCATTERED ACTIVITY AT
BEST OVER THE NORTHEASTERN HALF OF THE CWA THIS EVENING.
WITH AN UPPER TROUGH OVER THE EASTERN STATES AND A RIDGE TO OUR
WEST...THE AREA IS UNDER A WEST-NORTHWEST FLOW. A DISTURBANCE...BOTH
AT THE SURFACE AND ALOFT MOVES INTO SOUTHERN SASK LATER
TONIGHT...KEEPING SHOWERS/THUNDERSTORMS GOING OVERNIGHT MAINLY TO
THE NORTHEAST ZONES.
SUNDAY...DISTURBANCE MOVES SOUTHEAST AND THROUGH THE CWA BRINGING AN
INCREASE IN WEST WINDS DURING THE AFTERNOON. THEY SHOULD BE STRONG
ENOUGH TO CAUSE PROBLEMS FOR FORT PECK LAKE FROM NOON UNTIL 9
PM...SO ISSUED A LAKE WIND ADVISORY.
ON MONDAY...BACKDOOR FRONT THAT LIES NW TO SE ACROSS MONTANA SUNDAY
NIGHT HELPS TO FIRE UP THUNDERSTORMS AS A VORT MAX MOVES IN FROM THE
WEST. ACTIVITY MOVES IN FROM THE WEST WITH MORE ACTIVITY EXPECTED
DURING THE EVENING. TFJ
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...
AN UPPER LEVEL RIDGE IN THE WEST AND A PERSISTENT UPPER TROUGH
CENTERED OVER NORTHERN QUEBEC WILL MAINTAIN A NORTHWEST FLOW OVER
NORTHEAST MONTANA THROUGH MOST OF THE PERIOD. WEAK EMBEDDED
DISTURBANCES IN THE UPPER FLOW WILL BRING ISOLATED TO SCATTERED
THUNDERSTORMS TO THE REGION THROUGHOUT THE PERIOD.
MONDAY EVENING AND OVERNIGHT GFS SENDS A DISTURBANCE FLOWING
ALONG THE STATIONARY BOUNDARY THAT WILL INITIATE THUNDERSTORMS
ACROSS NEMONT. WITH SOME AGREEMENT FROM THE 00Z EC...WENT AHEAD
AND ADJUSTED POPS TO CHANCE.
TUESDAY THROUGH SATURDAY THE FLUCTUATING STATIONARY BOUNDARY AND
WEAK DISTURBANCES WILL GENERATE A FEW STORMS EACH DAY. THIS IS
REFLECTED IN THE INHERITED GRIDS AND NO CHANGES ARE PLANNED HERE.
SCT
SYNOPTIC SET UP... A LARGE HIGH PRESSURE HEAT DOME IS CENTERED
OVER THE LOWER INTER-MOUNTAIN WEST. A RIDGE SPUR RUNS NORTH OF THIS
DOME INTO BRITISH COLUMBIA. A LARGE TROUGH EXTENDS FROM THE
NORTHERN US PLAINS INTO MANITOBA AND UP THROUGH NUNAVUT. NORTHEAST
MONTANA LIES BETWEEN THESE TWO FEATURES IN A ZONAL TO NORTHWEST
FLOW PATTERN. ANOTHER LARGE TROUGH LIES OFF THE COAST OF BRITISH
COLUMBIA.
MONDAY NIGHT THROUGH THURSDAY NIGHT... NORTHWEST FLOW WILL END UP
ALLOWING HIGH POP CHANCE ACROSS THE NORTHEAST DRYING TOWARD THE
SOUTHWEST. THIS GRADIENT WILL BEGIN A BIT MORE SHARP MONDAY NIGHT
BUT WILL SLOWLY DIFFUSE OUT TOWARD THURSDAY NIGHT AS JETS AND
SHORTWAVES BECOME MORE FUZZY IN TIME. ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS DO EXIST ALMOST EVERY PERIOD.
FRIDAY ONWARD... THE PATTERN WILL BECOME A LITTLE MORE PROGRESSIVE
AS THE RIDGE TO THE WEST SETTLES OVER THE MONTANA HIGH PLAINS.
THIS SHOULD EDGE TEMPERATURES UP BUT POPS WILL PROBABLY REMAIN AS
THE ATMOSPHERE BECOMES MORE DESTABILIZED. HOWEVER... QPF IS
EXPECTED TO LOWER AS PLANTS BEGIN TO STRESS FROM PROGRESSIVELY
DRIER HOTTER DAYS AND SOILS FOLLOWED BY THE SURFACE LAYER OF THE
ATMOSPHERE DRY OUT. GAH
&&
.AVIATION...
GENERALLY VFR. HOWEVER A WEAK UPPER LEVEL DISTURBANCE FLOWING
OVER A STATIONARY SURFACE BOUNDARY WILL INITIATE ISOLATED TO
SCATTERED AFTERNOON/EVENING THUNDERSTORMS THAT COULD AFFECT ANY OF
THE TAF SITES. SCT
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY FROM NOON TO 9 PM MDT SUNDAY FOR FORT PECK
LAKE FOR CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN
VALLEY...GARFIELD...MCCONE...PETROLEUM.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
238 PM MDT SAT JUL 20 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH MONDAY...
CONVECTIVE ACTIVITY THIS AFTERNOON WILL CONTINUE TO DEVELOP OVER THE
NEXT COUPLE OF HOURS BUT SHOULD DIMINISH PRETTY QUICK WITHOUT THE
SHEAR IN PLACE. HRRR MODEL SHOWING JUST SCATTERED ACTIVITY AT BEST
OVER THE NORTHEASTERN HALF OF THE CWA THIS EVENING.
WITH AN UPPER TROUGH OVER THE EASTERN STATES AND A RIDGE TO OUR
WEST...THE AREA IS UNDER A WEST-NORTHWEST FLOW. A DISTURBANCE...BOTH
AT THE SURFACE AND ALOFT MOVES INTO SOUTHERN SASK LATER
TONIGHT...KEEPING SHOWERS/THUNDERSTORMS GOING OVERNIGHT MAINLY TO
THE NORTHEAST ZONES.
SUNDAY...DISTURBANCE MOVES SOUTHEAST AND THROUGH THE CWA BRINGING AN
INCREASE IN WEST WINDS DURING THE AFTERNOON. THEY SHOULD BE STRONG
ENOUGH TO CAUSE PROBLEMS FOR FORT PECK LAKE FROM NOON UNTIL 9
PM...SO ISSUED A LAKE WIND ADVISORY.
ON MONDAY...BACKDOOR FRONT THAT LIES NW TO SE ACROSS MONTANA SUNDAY
NIGHT HELPS TO FIRE UP THUNDERSTORMS AS A VORT MAX MOVES IN FROM THE
WEST. ACTIVITY MOVES IN FROM THE WEST WITH MORE ACTIVITY EXPECTED
DURING THE EVENING. TFJ
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...
AN UPPER LEVEL RIDGE IN THE WEST AND A PERSISTENT UPPER TROUGH
CENTERED OVER NORTHERN QUEBEC WILL MAINTAIN A NORTHWEST FLOW OVER
NORTHEAST MONTANA THROUGH MOST OF THE PERIOD. WEAK EMBEDDED
DISTURBANCES IN THE UPPER FLOW WILL BRING ISOLATED TO SCATTERED
THUNDERSTORMS TO THE REGION THROUGHOUT THE PERIOD.
MONDAY EVENING AND OVERNIGHT GFS SENDS A DISTURBANCE FLOWING
ALONG THE STATIONARY BOUNDARY THAT WILL INITIATE THUNDERSTORMS
ACROSS NEMONT. WITH SOME AGREEMENT FROM THE 00Z EC...WENT AHEAD
AND ADJUSTED POPS TO CHANCE.
TUESDAY THROUGH SATURDAY THE FLUCTUATING STATIONARY BOUNDARY AND
WEAK DISTURBANCES WILL GENERATE A FEW STORMS EACH DAY. THIS IS
REFLECTED IN THE INHERITED GRIDS AND NO CHANGES ARE PLANNED HERE.
SCT
SYNOPTIC SET UP... A LARGE HIGH PRESSURE HEAT DOME IS CENTERED
OVER THE LOWER INTER-MOUNTAIN WEST. A RIDGE SPUR RUNS NORTH OF THIS
DOME INTO BRITISH COLUMBIA. A LARGE TROUGH EXTENDS FROM THE
NORTHERN US PLAINS INTO MANITOBA AND UP THROUGH NUNAVUT. NORTHEAST
MONTANA LIES BETWEEN THESE TWO FEATURES IN A ZONAL TO NORTHWEST
FLOW PATTERN. ANOTHER LARGE TROUGH LIES OFF THE COAST OF BRITISH
COLUMBIA.
MONDAY NIGHT THROUGH THURSDAY NIGHT... NORTHWEST FLOW WILL END UP
ALLOWING HIGH POP CHANCE ACROSS THE NORTHEAST DRYING TOWARD THE
SOUTHWEST. THIS GRADIENT WILL BEGIN A BIT MORE SHARP MONDAY NIGHT
BUT WILL SLOWLY DIFFUSE OUT TOWARD THURSDAY NIGHT AS JETS AND
SHORTWAVES BECOME MORE FUZZY IN TIME. ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS DO EXIST ALMOST EVERY PERIOD.
FRIDAY ONWARD... THE PATTERN WILL BECOME A LITTLE MORE PROGRESSIVE
AS THE RIDGE TO THE WEST SETTLES OVER THE MONTANA HIGH PLAINS.
THIS SHOULD EDGE TEMPERATURES UP BUT POPS WILL PROBABLY REMAIN AS
THE ATMOSPHERE BECOMES MORE DESTABILIZED. HOWEVER... QPF IS
EXPECTED TO LOWER AS PLANTS BEGIN TO STRESS FROM PROGRESSIVELY
DRIER HOTTER DAYS AND SOILS FOLLOWED BY THE SURFACE LAYER OF THE
ATMOSPHERE DRY OUT. GAH
&&
.AVIATION...
GENERALLY VFR. HOWEVER A WEAK UPPER LEVEL DISTURBANCE FLOWING
OVER A STATIONARY SURFACE BOUNDARY WILL INITIATE ISOLATED TO
SCATTERED AFTERNOON/EVENING THUNDERSTORMS THAT COULD AFFECT ANY OF
THE TAF SITES. SCT
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY FROM NOON TO 9 PM MDT SUNDAY FOR FORT PECK
LAKE FOR CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN
VALLEY...GARFIELD...MCCONE...PETROLEUM.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
256 PM CDT SAT JUL 20 2013
.SYNOPSIS...
ISSUED AT 253 PM CDT SAT JUL 20 2013
THE H5 ANALYSIS THIS MORNING...HAS AN ACTIVE NW FLOW
PATTERN ACROSS THE NRN CONUS. HIGH PRESSURE WAS ANCHORED ACROSS THE
CENTRAL VALLEY OF CA...WITH A PERSISTENT BERMUDA HIGH PRESENT ACROSS
THE WESTERN ATLANTIC. A BROAD TROUGH OF LOW PRESSURE EXTENDED FROM
NRN QUEBEC INTO THE MID ATLANTIC STATES. ACROSS THE NRN ROCKIES AND
CENTRAL PLAINS...NUMEROUS SHORTWAVES WERE EMBEDDED IN THE NWRLY
FLOW. ONE OVER NWRN WYOMING...AND A SECOND OVER THE IDAHO PANHANDLE.
ANOTHER DISTURBANCE WAS NOTED OVER NWRN IA AS WELL. AT THE
SURFACE...SHOWERS AND THUNDERSTORMS HAVE CONTINUED ACROSS NORTHERN
NEBRASKA THIS MORNING AND EARLY THIS AFTERNOON...ALONG A WEAK
SURFACE BOUNDARY. TEMPERATURES AS OF 2 PM CDT RANGED FROM 68 IN RAIN
COOLED AIR AT ONEILL...TO 87 AT OGALLALA...IMPERIAL AND NORTH PLATTE.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 253 PM CDT SAT JUL 20 2013
SCATTERED THUNDERSTORMS THIS AFTERNOON ARE EXPECTED TO DEVELOP OVER
THE NEBRASKA PANHANDLE AND NORTHWEST NEBRASKA AND COALESCE INTO A
CONVECTIVE SYSTEM BY EARLY THIS EVENING. WITH THE DEEP SHEAR VECTORS
DIAGONAL TO THE LOW LEVEL BOUNDARY...IT APPEARS TO FAVOR THE
DEVELOPMENT OF A LINEAR CONVECTIVE SYSTEM. ACCORDING TO THE SHORT
RANGE HRRR AND RAP13...THE SYSTEM WILL AFFECT A LARGE PART OF THE
SANDHILLS AND SOUTHWEST NEBRASKA BY 01Z AND FINALLY CLEARING CENTRAL
NEBRASKA BY 09Z. THEY DO INDICATE SOME LINGERING SHOWERS AND
THUNDERSTORMS EVEN INTO EARLY SUNDAY.
INSTABILITY CONTINUES OVER WESTERN NEBRASKA SUNDAY AND THERE IS A
CHANCE OF ANOTHER CONVECTIVE SYSTEM DEVELOPING IN SOUTH DAKOTA AND
NORTHWEST NEBRASKA LATE SUNDAY MORNING OR EARLY AFTERNOON...THEN
CROSSING WESTERN NEBRASKA THROUGH THE AFTERNOON.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 253 PM CDT SAT JUL 20 2013
MID RANGE...SUNDAY NIGHT THROUGH TUESDAY...A FAIRLY ACTIVE PATTERN
WILL CONTINUE INTO TUESDAY...THANKS TO NWLY FLOW AND THE PRESENCE OF
EMBEDDED SHORTWAVES WITHIN THAT FLOW. BEGINNING SUNDAY
NIGHT...ANOTHER UPPER LEVEL DISTURBANCE WILL TRACK FROM THE CENTRAL
AND NORTHERN ROCKIES...ACROSS WESTERN AND NORTH CENTRAL NEBRASKA.
CONVECTION WILL BE ONGOING BY SUNDAY AFTERNOON AND IS EXPECTED TO
IMPACT MOST OF THE FORECAST AREA DURING THE EVENING AND OVERNIGHT
HOURS. ATTM...WILL PAINT THE HIGHEST POPS IN THE CENTRAL AND
SOUTHWESTERN CWA...AS THESE LOCATIONS WILL SEE THE BEST DEEP LAYER
SHEAR OF 30 TO 40 KTS. SHEAR IN THE NERN ZONES WILL RUN 10 TO 20 KTS
SUNDAY EVENING...SO ANY TSRAS IN THESE AREAS WILL BE FEW AND FAR
BETWEEN. WILL CONTINUE MENTION OF THUNDERSTORMS IN THE FORECAST
OVERNIGHT IN THE SOUTHWESTERN ZONES AS THERE ARE INDICATIONS OF THE
DEVELOPMENT OF A LOW LEVEL JET...WHICH BECOMES FOCUSED ACROSS SWRN
AND CENTRAL NEBRASKA OVERNIGHT SUNDAY NIGHT. CONVECTION ALONG WITH
THE EXITING DISTURBANCE...WILL FORCE A FRONTAL BOUNDARY THROUGH THE
FORECAST AREA ON MONDAY...STALLING THIS FEATURE ACROSS CENTRAL AND
EASTERN NEBRASKA MONDAY EVENING. ONCE AGAIN...UPPER LEVEL ENERGY
WILL ENTER THE CENTRAL PLAINS FROM THE ROCKIES LATE IN THE DAY
MONDAY...LEADING TO THE DEVELOPMENT OF THUNDERSTORMS. THERE IS SOME
DISAGREEMENT AS TO WHERE THE UPPER LEVEL ENERGY WILL TRACK DURING
THIS PERIOD SO CONFIDENCE IN LOCATION OF POPS IS LACKING ATTM.
DECIDED TO CONFINE POPS INVOF OF THE FRONTAL BOUNDARY...IE...EASTERN
CWA FOR MONDAY NIGHT. ON TUESDAY...EASTERLY WINDS WILL BECOME
SOUTHERLY BY AFTERNOON AS HIGH PRESSURE DRIFTS EAST INTO THE UPPER
MIDWEST. THE FRONTAL BOUNDARY WILL WASH OUT WHILE NORTHWESTERLY FLOW
ALOFT CONTINUES. ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS WILL
TRACK ACROSS THE REGION TUESDAY AFTERNOON AND TUESDAY NIGHT AS
ANOTHER UPPER LEVEL DISTURBANCE TRACKS FROM THE CENTRAL AND NORTHERN
ROCKIES ONTO THE CENTRAL PLAINS.
LONG RANGE...TUESDAY NIGHT THROUGH SATURDAY...A FAIRLY ACTIVE
PATTERN WILL CONTINUE INTO THE EXTENDED PERIODS WITH ABUNDANT LOW
LEVEL MOISTURE AND PERSISTENT WESTERLY AND NORTHWESTERLY FLOW ALOFT.
NUMEROUS SHORTWAVES WILL TRACK ACROSS THE CENTRAL ROCKIES ACROSS THE
CENTRAL PLAINS THROUGH THE PERIOD...LEADING TO A GOOD CHANCE FOR
PRECIPITATION DURING THE PERIOD. TEMPERATURES WILL BE SEASONAL WITH
HIGHS IN THE 80S AND LOWS IN THE UPPER 50S AND LOWER 60S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 253 PM CDT SAT JUL 20 2013
SCATTERED THUNDERSTORMS ARE EXPECTED THIS EVENING OVER A LARGE PART
OF CENTRAL AND WESTERN NEBRASKA. WITH STORMS FORMING INTO A LINE
LATE THIS AFTERNOON...THE PROBABILITY OF THUNDERSTORMS AT ANY ONE
SITE IS LIKELY TO BE 50 PERCENT OR HIGHER. AS A RESULT THUNDER IS IN
THE TERMINAL FORECASTS FOR VTN AND LBF THIS EVENING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CLB
SHORT TERM...SPRINGER
LONG TERM...CLB
AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1248 PM CDT SAT JUL 20 2013
.UPDATE...
ISSUED AT 1247 PM CDT SAT JUL 20 2013
UPDATED HWO IS OUT AND HAS OUR THOUGHTS THIS AFTN. ADDITIONAL
TSTMS COULD DEVELOP AT ANY TIME. WE/VE BEEN WATCHING A DECENT
STORM LEAVE WEBSTER FOR THAYER COUNTY WITH SOME TORRENTIAL
RAINFALL. THE TSTM CLUSTERS OVER THE PANHANDLE AND SANDHILLS ARE
EXPECTED TO INCREASE IN COVERAGE/INTENSITY AND THAT ACTIVITY
SHOULD ARRIVE HERE TNGT.
UPDATE ISSUED AT 1107 AM CDT SAT JUL 20 2013
THE INITIAL COMPOSITE OUTFLOW BOUNDARY CONTS DROPPING STEADILY S
AT 22 KTS AND WILL ARRIVE AT THE KS BORDER AROUND 1215 PM. SCT
SHWRS WERE DEVELOPING ATOP THIS OUTFLOW AND THIS POTENTIAL IS
EXPECTED TO CONT DESPITE THE SEEMINGLY UNFAVORABLE ENVIRONMENT.
VIS SATPIX SHOWED ANOTHER OUTFLOW BOUNDARY /FROM THE TSTMS HEADING
INTO NE NEB/ THAT WILL MOVE INTO THE NRN FRINGE OF THE FCST AREA
SHORTLY /ORD-GREELEY/.
THE OAX SOUNDING WAS VERY DRY BELOW 700 MB FROM OVERNGT
SUBSIDENCE. HOWEVER...THE OUTFLOW IS CLEARLY ENOUGH TO INITIATE
SHWRS WITH EMBEDDED THUNDER. SO THIS REALLY COMPLICATES THE
SITUATION TODAY...AND LOWERS CONFIDENCE IN HOW THINGS WILL
DEVELOP/EVOLVE. REGIONAL 88D WIND PROFILES SHOW DEEP E-NE FLOW UP
TO 9K FT...WHICH WOULD BE ENUF TO INITIATE SHWRS/THUNDER BASED ON
THE OAX SOUNDING. GLD AND TOP HAVE MORE SHALLOW S FLOW...WHERE
MSTR IS HIGHER. SO WOULD EXPECT HIGHER MSTR TO ADVECT N AND BE
INTERCEPTED BY THE OUTFLOW. HOWEVER...ANOTHER NEGATIVE FACTOR IS
THE EXTENSIVE CLOUD COVER BEHIND THE BOUNDARY. THE INHIBITED
HEATING MAKES MODELED CAPE QUESTIONABLE. EVEN THE NE LOW-MID LVL
FLOW OVER NEB IS NOT BEING CAPTURED BY THE MODELS /THEY CURRENTLY
HAVE SE WINDS AND MAINTAIN THEM/. SO FCST VALUES OF DEEP LAYER
SHEAR ARE LESS CERTAIN.
SO FOR NOW BELIEVE THE HIGHEST FOCUS FOR SVR TSTM POTENTIAL SHOULD
BE IN SUNNIEST AREAS /CURRENTLY S AND W OF THE TRI-CITIES/.
THE FCST AREA WILL BE IN THE RRQ OF A 60 KT ULJ. THIS SHOULD
PROVIDE SUFFICIENT SHEAR FOR THE STRONGEST/TALLEST STORMS AND
WOULD ESTIMATE MLCAPE OF 1500-2000 J/KG OF MLCAPE IN THE SUNNIEST
AREAS.
STORM MOVEMENT FOR INDIVIDUAL/NON-MULTICELL STORMS WILL BE EAST
AROUND 10 KTS OVER NRN KS AND AROUND 20 KTS OVER S-CNTRL NEB.
UPDATE ISSUED AT 944 AM CDT SAT JUL 20 2013
AS EXPECTED MULTIPLE TSTM CLUSTERS DEVELOPED LAST NGT OVER SD AND
ARE CURRENTLY ON-GOING ALONG THE SD-NEB BORDER. A SWD MOVING
OUTFLOW BOUNDARY AS EMANATED FROM THESE CLUSTERS AND IS
APPROACHING I-80 PER VIS SATELLITE ANIMATION. THIS WILL INCREASE
THE SHEAR AS SFC WINDS ARE NE BEHIND THIS BOUNDARY. AM STILL
EVALUATING TSTM POTENTIAL FOR LATER TODAY BUT THE INITIAL LOOK AT
THE LBF/OAX 12Z SOUNDINGS DOES NOT LOOK GOOD...VERY DRY. WILL
HAVE MORE LATER ON THIS.
OTHERWISE...SOME SHORT-TERM ENHANCEMENTS HAVE BEEN MADE TO CLOUDS/
WX/POPS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM CDT SAT JUL 20 2013
WE ARE LOOKING AT ONE OF OUR BETTER CHANCES OF SHOWERS AND
THUNDERSTORMS THIS EVENING INTO TONIGHT.
THIS IS A DIFFICULT FORECAST WHEN IT COMES TO THE CHANCE OF
PRECIPITATION. WE HAVE BEEN DRY ACROSS THE FORECAST AREA EARLY THIS
MORNING. HOWEVER...A FEW FORECAST MODELS LIKE THE HRRR ATTEMPT TO
DEVELOP SHOWERS AND THUNDERSTORMS ALONG OLD OUTFLOW BOUNDARIES A
LITTLE LATER THIS MORNING. OVERALL FORCING IS WEAK THIS MORNING AND
WILL ONLY CALL FOR LOW END SLIGHT POPS THROUGH NOON ACROSS NORTH
CENTRAL KANSAS AND FOR AREAS PRIMARILY ALONG AND WEST OF HIGHWAY
281. THUNDERSTORMS ARE MOST LIKELY TO DEVELOP OVER THE NEBRASKA
SANDHILLS INTO SW SOUTH DAKOTA DURING THE MID TO LATE AFTERNOON
HOURS ALONG A SOUTHEASTWARD MOVING SFC TROUGH OF LOW PRESSURE.
SEVERAL FORECAST MODELS SUCH AS THE 06Z NAM AND 00Z GFS CONGEAL
CONVECTION THIS EVENING INTO A LARGE RAIN MAKING CLUSTER CALLED
AN MCS OR MESOSCALE CONVECTIVE SYSTEM THAT WOULD TRACK ACROSS OUR
FORECAST AREA. CONSEQUENTLY...WILL CONTINUE TO CARRY THE LIKELY
POPS FOR THIS EVENING. DEEP LAYER WIND SHEAR VALUES WILL GENERALLY
RANGE FROM 30 TO 35 KTS AND MLCAPE WILL BE MODEST...REACHING UP
CLOSE TO 2000 J/KG. THEREFORE...THE ENVIRONMENT WILL SUPPORT THE
POSSIBILITY OF SEVERE THUNDERSTORMS WITH THE PRIMARY FOCUS BEING
DURING THE EVENING HOURS. THIS IS PRIMARILY A WIND AND HAIL THREAT
WITH NOT MUCH OF A TORNADO THREAT GIVEN THE SHEAR IS WEAK IN THE
LOWEST ATMOSPHERIC LAYERS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 408 AM CDT SAT JUL 20 2013
MAIN FORECAST CONCERNS WILL BE THE CHANCES FOR THUNDERSTORMS AND
TEMPERATURES.
MODELS ARE SIMILAR IN THE MAIN FEATURES DURING THIS PERIOD WITH
NORTHWEST FLOW ACROSS THE AREA AND SEVERAL UPPER LEVEL WAVES MOVE
THROUGH THE REGION. EACH OF THEM HAVE THE POTENTIAL TO BRING A
CHANCE FOR THUNDERSTORMS TO THE AREA. THE MAIN DIFFERENCES IN THE
MODELS IS THAT THE TIMING OF THE INDIVIDUAL WAVES HAS SOME
DIFFERENCES AND HOW STRONG THEY ARE. IT DEFINITELY WILL NOT RAIN
EVERY DAY OR AT EVERY LOCATION...BUT THERE IS MAINLY SMALL CHANCES
NEARLY EVERY DAY.
THE PRECIPITATION FROM SATURDAY NIGHT WILL MOVE OUT OF THE AREA
SUNDAY MORNING BUT ANOTHER WAVE WILL MOVE INTO THE AREA SUNDAY
AFTERNOON AND EVENING AND BRING ANOTHER CHANCE FOR THUNDERSTORMS.
THE THUNDERSTORMS SHOULD BE NEARLY OUT OF THE AREA DURING THE
OVERNIGHT HOURS SUNDAY NIGHT. MONDAY MORNING WILL ALSO CONTINUE DRY
BEFORE THE NEXT WAVE MOVES INTO THE AREA MONDAY AFTERNOON AND MONDAY
NIGHT. ANOTHER WAVE MOVES IN TUESDAY AND TUESDAY NIGHT. THIS IS A
FAIRLY STRONG WAVE AND CHANCES ARE A LITTLE BETTER FOR SOME
PRECIPITATION...WITH A SURFACE LOW AND WEAK COLD FRONT THAT MOVE
THROUGH THE AREA.
ONCE THE PRECIPITATION MOVES OUT TUESDAY NIGHT...WEDNESDAY AND
WEDNESDAY NIGHT LOOK TO BE DRY WITH A BREAK IN THE SERIES OF UPPER
LEVEL WAVES. BEHIND THE COLD FRONT THERE IS A COOLER SURFACE HIGH
AND TEMPERATURES WILL BE CLOSER TO NORMAL FOR THIS TIME OF YEAR.
THURSDAY THROUGH FRIDAY THERE IS ANOTHER UPPER LEVEL WAVE THAT MOVES
THROUGH THE AREA. THIS ONE IS A LITTLE STRONGER THAN SOME OF THE
OTHERS. THERE IS ANOTHER SURFACE LOW AND COLD FRONT THAT MOVES
THROUGH AND THE CHANCES FOR THUNDERSTORMS RETURN TO THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1247 PM CDT SAT JUL 20 2013
THIS AFTN: VFR BUT ISOLATED SHWRS/TSTMS WILL BE NEARBY WITH
POCKETS OF MVFR/IFR VSBYS IN +RA. WATCH FOR SHORT-TERM AMENDMENTS
AS WE WILL PROVIDE ADDITIONAL DETAILS IF THE TERMINAL IS
THREATENED. NE WINDS WILL CONT 10-20 KTS BUT THIS IS DUE TO TSTM
OUTFLOW AND NOT PART OF THE BROADER FLOW. SO IT REMAINS UNCERTAIN
WHEN THE WIND RETURNS TO E OR SE.
TNGT: VFR BUT A 1-2 HR PERIOD OF TSTMS IS POSSIBLE. JUST NOT SURE
ON EXACT TIMING OR OCCURRENCE. FUTURE TAFS MAY NEED TO INCLUDE
MORE DEFINITIVE TIME FRAME. WIND SHOULD BECOME SE BELOW 10 KTS.
THERE IS A SLGT CHANCE OF IFR FOG IS SKIES CLEAR AND WINDS TURN
LGT BEHIND TSTMS.
SUN THRU 18Z: IFR FOG POSSIBLE TO START...BUT IT/S NOT IN THE TAF
UNTIL WE SEE IF TSTMS DEVELOP. WINDS WILL BE LGT AND VARIABLE.
CIG CONFIDENCE: MEDIUM
VSBY CONFIDENCE: MEDIUM
WIND CONFIDENCE: LOW
WX CONFIDENCE: LOW
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...WESELY
LONG TERM...JCB
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1107 AM CDT SAT JUL 20 2013
.UPDATE...
ISSUED AT 1107 AM CDT SAT JUL 20 2013
THE INITIAL COMPOSITE OUTFLOW BOUNDARY CONTS DROPPING STEADILY S
AT 22 KTS AND WILL ARRIVE AT THE KS BORDER AROUND 1215 PM. SCT
SHWRS WERE DEVELOPING ATOP THIS OUTFLOW AND THIS POTENTIAL IS
EXPECTED TO CONT DESPITE THE SEEMINGLY UNFAVORABLE ENVIRONMENT.
VIS SATPIX SHOWED ANOTHER OUTFLOW BOUNDARY /FROM THE TSTMS HEADING
INTO NE NEB/ THAT WILL MOVE INTO THE NRN FRINGE OF THE FCST AREA
SHORTLY /ORD-GREELEY/.
THE OAX SOUNDING WAS VERY DRY BELOW 700 MB FROM OVERNGT
SUBSIDENCE. HOWEVER...THE OUTFLOW IS CLEARLY ENOUGH TO INITIATE
SHWRS WITH EMBEDDED THUNDER. SO THIS REALLY COMPLICATES THE
SITUATION TODAY...AND LOWERS CONFIDENCE IN HOW THINGS WILL
DEVELOP/EVOLVE. REGIONAL 88D WIND PROFILES SHOW DEEP E-NE FLOW UP
TO 9K FT...WHICH WOULD BE ENUF TO INITIATE SHWRS/THUNDER BASED ON
THE OAX SOUNDING. GLD AND TOP HAVE MORE SHALLOW S FLOW...WHERE
MSTR IS HIGHER. SO WOULD EXPECT HIGHER MSTR TO ADVECT N AND BE
INTERCEPTED BY THE OUTFLOW. HOWEVER...ANOTHER NEGATIVE FACTOR IS
THE EXTENSIVE CLOUD COVER BEHIND THE BOUNDARY. THE INHIBITED
HEATING MAKES MODELED CAPE QUESTIONABLE. EVEN THE NE LOW-MID LVL
FLOW OVER NEB IS NOT BEING CAPTURED BY THE MODELS /THEY CURRENTLY
HAVE SE WINDS AND MAINTAIN THEM/. SO FCST VALUES OF DEEP LAYER
SHEAR ARE LESS CERTAIN.
SO FOR NOW BELIEVE THE HIGHEST FOCUS FOR SVR TSTM POTENTIAL SHOULD
BE IN SUNNIEST AREAS /CURRENTLY S AND W OF THE TRI-CITIES/.
THE FCST AREA WILL BE IN THE RRQ OF A 60 KT ULJ. THIS SHOULD
PROVIDE SUFFICIENT SHEAR FOR THE STRONGEST/TALLEST STORMS AND
WOULD ESTIMATE MLCAPE OF 1500-2000 J/KG OF MLCAPE IN THE SUNNIEST
AREAS.
STORM MOVEMENT FOR INDIVIDUAL/NON-MULTICELL STORMS WILL BE EAST
AROUND 10 KTS OVER NRN KS AND AROUND 20 KTS OVER S-CNTRL NEB.
UPDATE ISSUED AT 944 AM CDT SAT JUL 20 2013
AS EXPECTED MULTIPLE TSTM CLUSTERS DEVELOPED LAST NGT OVER SD AND
ARE CURRENTLY ON-GOING ALONG THE SD-NEB BORDER. A SWD MOVING
OUTFLOW BOUNDARY AS EMANATED FROM THESE CLUSTERS AND IS
APPROACHING I-80 PER VIS SATELLITE ANIMATION. THIS WILL INCREASE
THE SHEAR AS SFC WINDS ARE NE BEHIND THIS BOUNDARY. AM STILL
EVALUATING TSTM POTENTIAL FOR LATER TODAY BUT THE INITIAL LOOK AT
THE LBF/OAX 12Z SOUNDINGS DOES NOT LOOK GOOD...VERY DRY. WILL
HAVE MORE LATER ON THIS.
OTHERWISE...SOME SHORT-TERM ENHANCEMENTS HAVE BEEN MADE TO CLOUDS/
WX/POPS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM CDT SAT JUL 20 2013
WE ARE LOOKING AT ONE OF OUR BETTER CHANCES OF SHOWERS AND
THUNDERSTORMS THIS EVENING INTO TONIGHT.
THIS IS A DIFFICULT FORECAST WHEN IT COMES TO THE CHANCE OF
PRECIPITATION. WE HAVE BEEN DRY ACROSS THE FORECAST AREA EARLY THIS
MORNING. HOWEVER...A FEW FORECAST MODELS LIKE THE HRRR ATTEMPT TO
DEVELOP SHOWERS AND THUNDERSTORMS ALONG OLD OUTFLOW BOUNDARIES A
LITTLE LATER THIS MORNING. OVERALL FORCING IS WEAK THIS MORNING AND
WILL ONLY CALL FOR LOW END SLIGHT POPS THROUGH NOON ACROSS NORTH
CENTRAL KANSAS AND FOR AREAS PRIMARILY ALONG AND WEST OF HIGHWAY
281. THUNDERSTORMS ARE MOST LIKELY TO DEVELOP OVER THE NEBRASKA
SANDHILLS INTO SW SOUTH DAKOTA DURING THE MID TO LATE AFTERNOON
HOURS ALONG A SOUTHEASTWARD MOVING SFC TROUGH OF LOW PRESSURE.
SEVERAL FORECAST MODELS SUCH AS THE 06Z NAM AND 00Z GFS CONGEAL
CONVECTION THIS EVENING INTO A LARGE RAIN MAKING CLUSTER CALLED
AN MCS OR MESOSCALE CONVECTIVE SYSTEM THAT WOULD TRACK ACROSS OUR
FORECAST AREA. CONSEQUENTLY...WILL CONTINUE TO CARRY THE LIKELY
POPS FOR THIS EVENING. DEEP LAYER WIND SHEAR VALUES WILL GENERALLY
RANGE FROM 30 TO 35 KTS AND MLCAPE WILL BE MODEST...REACHING UP
CLOSE TO 2000 J/KG. THEREFORE...THE ENVIRONMENT WILL SUPPORT THE
POSSIBILITY OF SEVERE THUNDERSTORMS WITH THE PRIMARY FOCUS BEING
DURING THE EVENING HOURS. THIS IS PRIMARILY A WIND AND HAIL THREAT
WITH NOT MUCH OF A TORNADO THREAT GIVEN THE SHEAR IS WEAK IN THE
LOWEST ATMOSPHERIC LAYERS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 408 AM CDT SAT JUL 20 2013
MAIN FORECAST CONCERNS WILL BE THE CHANCES FOR THUNDERSTORMS AND
TEMPERATURES.
MODELS ARE SIMILAR IN THE MAIN FEATURES DURING THIS PERIOD WITH
NORTHWEST FLOW ACROSS THE AREA AND SEVERAL UPPER LEVEL WAVES MOVE
THROUGH THE REGION. EACH OF THEM HAVE THE POTENTIAL TO BRING A
CHANCE FOR THUNDERSTORMS TO THE AREA. THE MAIN DIFFERENCES IN THE
MODELS IS THAT THE TIMING OF THE INDIVIDUAL WAVES HAS SOME
DIFFERENCES AND HOW STRONG THEY ARE. IT DEFINITELY WILL NOT RAIN
EVERY DAY OR AT EVERY LOCATION...BUT THERE IS MAINLY SMALL CHANCES
NEARLY EVERY DAY.
THE PRECIPITATION FROM SATURDAY NIGHT WILL MOVE OUT OF THE AREA
SUNDAY MORNING BUT ANOTHER WAVE WILL MOVE INTO THE AREA SUNDAY
AFTERNOON AND EVENING AND BRING ANOTHER CHANCE FOR THUNDERSTORMS.
THE THUNDERSTORMS SHOULD BE NEARLY OUT OF THE AREA DURING THE
OVERNIGHT HOURS SUNDAY NIGHT. MONDAY MORNING WILL ALSO CONTINUE DRY
BEFORE THE NEXT WAVE MOVES INTO THE AREA MONDAY AFTERNOON AND MONDAY
NIGHT. ANOTHER WAVE MOVES IN TUESDAY AND TUESDAY NIGHT. THIS IS A
FAIRLY STRONG WAVE AND CHANCES ARE A LITTLE BETTER FOR SOME
PRECIPITATION...WITH A SURFACE LOW AND WEAK COLD FRONT THAT MOVE
THROUGH THE AREA.
ONCE THE PRECIPITATION MOVES OUT TUESDAY NIGHT...WEDNESDAY AND
WEDNESDAY NIGHT LOOK TO BE DRY WITH A BREAK IN THE SERIES OF UPPER
LEVEL WAVES. BEHIND THE COLD FRONT THERE IS A COOLER SURFACE HIGH
AND TEMPERATURES WILL BE CLOSER TO NORMAL FOR THIS TIME OF YEAR.
THURSDAY THROUGH FRIDAY THERE IS ANOTHER UPPER LEVEL WAVE THAT MOVES
THROUGH THE AREA. THIS ONE IS A LITTLE STRONGER THAN SOME OF THE
OTHERS. THERE IS ANOTHER SURFACE LOW AND COLD FRONT THAT MOVES
THROUGH AND THE CHANCES FOR THUNDERSTORMS RETURN TO THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 529 AM CDT SAT JUL 20 2013
THE WIND WILL REMAIN LIGHT AND AT TIMES VARIABLE THIS MORNING
ALTHOUGH BECOMING MORE SOUTHEASTERLY WITH TIME. THE WIND WILL
THEN INCREASE BY EARLY AFTERNOON THANKS TO DIURNAL HEATING AND
SUBSEQUENTLY DIE DOWN BY EARLY EVENING ONCE WE LOSE THE AFTERNOON
HEATING. WE HAVE AN INCREASING CHANCE OF THUNDERSTORMS AS WE HEAD
THROUGH THE AFTERNOON AND ESPECIALLY BY EVENING. THE WIND
WILL LIKELY BECOME VARIABLE AND RATHER GUSTY IN AND AROUND
ANY THUNDERSTORMS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...WESELY
LONG TERM...JCB
AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS RALEIGH NC
230 PM EDT SAT JUL 20 2013
.SYNOPSIS...
A SURFACE TROUGH OF LOW PRESSURE...IN A MOIST AIR MASS...WILL REMAIN
OVER THE REGION AT LEAST THROUGH THE MIDDLE OF THE UPCOMING WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1055 AM SATURDAY...
CLOUDS WERE HANGING IN ACROSS MUCH OF CENTRAL NORTH CAROLINA THIS
MORNING. THESE CLOUDS SHOULD GRADUALLY MIX DURING THE LATE MORNING...
AND ALREADY THERE WERE MORE THIN SPOTS AND BREAKS OVER THE WESTERN
PIEDMONT ON THE VISIBLE SATELLITE IMAGES. BUFR SOUNDINGS AND
LOW-LEVEL MOISTURE FIELDS WOULD SUGGEST MIXING SHOULD TAKE PLACE AS
WELL TO A PARTLY SUNNY SKY ON AVERAGE...LIKELY MORE MOSTLY SUNNY FOR
A WHILE MAINLY OVER PARTS OF THE SOUTHERN COASTAL PLAIN. FOR THE
REST OF THE DAY INTO THIS EVENING...A SURFACE TROUGH WILL REMAIN
NEAR THE EDGE OF THE FOOTHILLS AND THE PIEDMONT...WITH AN 850MB
TROUGH ESSENTIALLY IN THE SAME LOCATION. 0-6KM SHEAR IS WEAK...TO
AROUND 10KT AT BEST...AND WITH A SLIGHTLY STEEPER LAPSE RATE ABOVE
THE INVERSION NOTED ON THE KGSO AND KRNK SOUNDINGS COMPARED TO
KMHX...OVERALL INSTABILITY SHOULD BE GREATER OVER THE NORTHWEST
PIEDMONT DURING THE LATE AFTERNOON. A SMALL CLUSTER OF SHOWERS AND
THUNDERSTORMS WAS LOCATED OVER THE FAR NORTHWEST PART OF THE STATE
EARLY THIS MORNING...AND ANY ASSOCIATED MID-LEVEL VORTICITY WITH
THAT CLUSTER COULD HELP...ALONG WITH THE SURFACE AND 850MB TROUGHS
AND BETTER INSTABILITY...TO GENERATE SCATTERED THUNDERSTORMS
PARTICULARLY IN VICINITY OF THE INTERSTATE 85 CORRIDOR DURING THE
AFTERNOON INTO THE EARLY EVENING. THE LATEST SPC MESOANALYSIS SHOWS
A RELATIVE MAXIMUM OF DOWNDRAFT CAPE OVER CENTRAL NORTH CAROLINA...
TO NEAR 800J/KG...THOUGH SHEAR AND 1000-500MB LAPSE RATES ARE
WEAK...AND WINDS ALOFT SHOULD LIGHTEN SOME...TO VALUES AT 925MB ONLY
NEAR 10 TO 20KT BY 18Z. THE SPC DAY ONE HAS A FIVE PERCENT LINE FOR
SEVERE STORMS FOR WIND MAINLY FROM THE TRIANGLE NORTH...AND IT IS IN
THIS AREA...MAINLY AGAIN ALONG AND NORTH OF INTERSTATE 85...WHERE
HIGHER THETA-E AIR IN COMBINATION WITH SLIGHTLY BETTER LAPSE RATES
COMPARED TO THE REST OF CENTRAL NORTH CAROLINA COULD RESULT IN A
STORM WITH A WIND GUST AROUND 50 MPH. OVER THE FAR EAST AND
SOUTHEAST...SUCH AS EAST OF I-95...THE LATEST RUC SHOWS LIMITED
INSTABILITY AND GREATER MID-LEVEL RIDGING SUCH THAT THE POTENTIAL
FOR SHOWERS AND THUNDERSTORMS SHOULD BE LESSER THERE. ANY SHOWERS
AND THUNDERSTORMS SHOULD TEND TO DIMINISH DIURNALLY. 1000-850MB
THICKNESSES ARE SLIGHTLY REDUCED FROM THOSE FORECAST FRIDAY...AND
WITH THE CLOUDS TO START PULLED BACK A DEGREE OR TWO THE HIGHS IN
THE TRIAD. OVERNIGHT LOWS IN THE LOWER TO MID 70S.
&&
.SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
AS OF 245 AM SATURDAY...
SHORTWAVE ENERGY EMBEDDED IN THE MAIN BELT OF WESTERLIES ALONG THE
US-CANADA BORDER WILL CONTINUE TRACK EAST ACROSS THE NORTHEAST AND
NORTHERN MID-ATLANTIC STATES ON SUNDAY. IT IS BECOMING INCREASINGLY
MORE APPARENT...THAT THE SURFACE FRONTAL ZONE WILL STALL NORTH OF
THE AREA...EXTENDING FROM THE SOUTHERN OHIO VALLEY AND JUST SOUTH OF
THE NATIONS CAPITAL. WITH THE APPRECIABLE FORCING/LIFT REMAINING
NORTH OF THE AREA...LOOKS LIKE CONVECTION WILL STILL HAVE MAINLY A
DIURNAL MODE...INITIALLY FIRING ALONG THE PIEDMONT TROUGH AND
DIFFERENTIAL HEATING OF THE HIGHER TERRAIN ALONG THE MTNS/FTHLS AND
SEABREEZE INTERACTION IN THE EAST. WITH INCREASING PWATS TO OR ABOVE
2.0"...COVERAGE SHOULD BE GREATER THAN THE PAST FEW DAYS...WITH
HIGHEST PROBABILITIES IN THE WEST. AN ISOLATED STRONG TO SEVERE
STORM CANNOT BE RULED OUT GIVEN THE MODERATE TO STRONG
INSTABILITY...BUT WEAK FLOW ALOFT SHOULD LIMIT A MORE ORGANIZED
SEVERE THREAT. ADDITIONALLY...ANY SLOW MOVING OR TRAINING STORMS
COULD RESULT IN LOCALIZED FLOODING.
HIGHS IN THE UPPER 80S TO LOWER 90S. LOWS IN THE LOWER 70S.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 230 PM SATURDAY...
MONDAY THROUGH TUESDAY NIGHT...
EARLY THIS WEEK...BROAD TROUGHING WILL CONTINUE TO EVOLVE OVER THE
EASTERN US... WHILE A QUASI-STATIONARY FRONTAL ZONE NEAR THE
MASON-DIXON LINE REMAINS TO OUR NORTH. A PAIR OF WEAK UPPER
DISTURBANCES SHOULD IMPACT THE AREA AS MONDAY AND TUESDAY AS THE
UPPER TROUGH BEGINS A SLOW AMPLIFICATION. THE FIRST DISTURBANCE
WILL BE THE REMNANTS OF A WEAK UPPER LOW CURRENTLY OVER
LOUISIANA...WHICH DYNAMIC TROPOPAUSE MAPS SHOW LIFTING ACROSS
CENTRAL AND WESTERN NC MONDAY AFTERNOON. THE SECOND AND LIKELY
STRONGER DISTURBANCE IS ASSOCIATED WITH ENERGY MAKING ITS WAY
ACROSS INTO THE NORTHERN PLAINS. CONFIDENCE IN THE TIMING/IMPACTS
OF EITHER OF THESE DISTURBANCES IS ONLY MEDIUM AT DAYS 3 AND 4...BUT
THEY WOULD LIKELY ENHANCE CONVECTION IN WHAT WILL BE A MODERATELY
UNSTABLE AIRMASS WITH DEWPOINTS IN THE LOWER 70S AND PW BACK UP TO
NEAR 2 INCHES. WILL INDICATE THE HIGHEST POPS OVER THE WESTERN
PIEDMONT MONDAY AND OVER THE COASTAL PLAIN ON TUESDAY. WHILE STRONG
STORMS WILL BE POSSIBLE...WEAK FLOW ALOFT DOESN`T SUPPORT A
SIGNIFICANT SEVERE THREAT. HIGHS IN THE UPPER 80S AND AROUND 90
EACH DAY...WITH A SLIGHT CHANCE OF A LINGERING STORM OVERNIGHT.
WEDNESDAY THROUGH SATURDAY...
MODELS ARE IN GOOD AGREEMENT ON THE MEAN TROUGH PERSISTING OVER THE
EASTERN US THROUGH THE END OF THE WEEK...THOUGH WITH A FAIR AMOUNT
OF UNCERTAINTY REGARDING THE DETAILS OF NUMEROUS DISTURBANCES MOVING
FROM THE MIDWEST TO THE SOUTHEASTERN AND MID-ATLANTIC STATES. A
WEAK FRONTAL ZONE TO OUR NORTH IS PROJECTED TO SLIP SOUTH AND
POTENTIALLY MERGE WITH PIEDMONT TROUGH AS THE UPPER TROUGH BECOMES
SLIGHTLY MORE AMPLIFIED. NO SIGNIFICANT AIRMASS CHANGE IS EXPECTED
WITH THE FRONT...AND WHILE SCATTERED CONVECTION SHOULD BE PRIMARILY
DIURNAL EACH DAY...CYCLONIC FLOW ALOFT AND THE PRESENCE OF THE
BETTER LOW LEVEL CONVERGENCE MAY SUPPORT BETTER POTENTIAL FOR
CONVECTION CONTINUING OVERNIGHT. TEMPS WILL CONTINUE
TO NEAR NORMAL...UPPER 80S FOR HIGHS AND LOWER 70S FOR LOWS.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 155 PM SATURDAY...
MOSTLY VFR CONDITIONS WILL PREVAIL THROUGH THE EARLY PART OF THE 18Z
VALID TAF PERIOD...AS LINGERING MVFR CEILINGS CONTINUE TO RISE AND
SCATTER EARLY THIS SATURDAY AFTERNOON. IN VICINITY OF THE TRIAD...AND
ALONG THE INTERSTATE 85 CORRIDOR...THERE IS A BETTER CHANCE COMPARED
TO THE REST OF CENTRAL NORTH CAROLINA OF SHOWERS AND THUNDERSTORMS
THIS AFTERNOON INTO THIS EVENING. OVERNIGHT...THE PRIMARY AVIATION
ISSUE WILL BE THE DEVELOPMENT OF LOW CEILINGS. SOME FORECAST
GUIDANCE SUGGESTS THE PROBABILITY OF LOW CLOUDS EARLY SUNDAY TO BE
AT LEAST AS HIGH AS THIS SATURDAY MORNING...AND AS A RESULT
ANTICIPATE FAIRLY WIDESPREAD IFR CONDITIONS AROUND SUNRISE SUNDAY.
CEILINGS SHOULD GRADUALLY RISE INTO MVFR AND LIKELY VFR THROUGH THE
MORNING SUNDAY...BEGINNING AFTER 13Z TO 14Z.
BEYOND THE 18Z VALID TAF PERIOD...A MOIST AIR MASS CONTINUES OVER
CENTRAL NORTH CAROLINA. GIVEN LITTLE AIR MASS CHANGE...AVIATION
INTERESTS SHOULD PREPARE FOR AT LEAST SCATTERED...MAINLY AFTERNOON
AND EVENING SHOWERS AND THUNDERSTORMS EACH DAY...WITH A FEW SHOWERS
AND STORMS POSSIBLY LINGERING THROUGH THE OVERNIGHT HOURS. LATE
NIGHT AND EARLY MORNING FOG WILL HAMPER VISIBILITIES ESPECIALLY
WHERE RAIN TENDS TO CONCENTRATE AND OVERNIGHT WINDS TURN LIGHT.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...CBL/DJF
SHORT TERM...BLS
LONG TERM...BLS
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
155 PM EDT SAT JUL 20 2013
.SYNOPSIS...
A SURFACE TROUGH OF LOW PRESSURE...IN A MOIST AIR MASS...WILL REMAIN
OVER THE REGION AT LEAST THROUGH THE MIDDLE OF THE UPCOMING WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1055 AM SATURDAY...
CLOUDS WERE HANGING IN ACROSS MUCH OF CENTRAL NORTH CAROLINA THIS
MORNING. THESE CLOUDS SHOULD GRADUALLY MIX DURING THE LATE MORNING...
AND ALREADY THERE WERE MORE THIN SPOTS AND BREAKS OVER THE WESTERN
PIEDMONT ON THE VISIBLE SATELLITE IMAGES. BUFR SOUNDINGS AND
LOW-LEVEL MOISTURE FIELDS WOULD SUGGEST MIXING SHOULD TAKE PLACE AS
WELL TO A PARTLY SUNNY SKY ON AVERAGE...LIKELY MORE MOSTLY SUNNY FOR
A WHILE MAINLY OVER PARTS OF THE SOUTHERN COASTAL PLAIN. FOR THE
REST OF THE DAY INTO THIS EVENING...A SURFACE TROUGH WILL REMAIN
NEAR THE EDGE OF THE FOOTHILLS AND THE PIEDMONT...WITH AN 850MB
TROUGH ESSENTIALLY IN THE SAME LOCATION. 0-6KM SHEAR IS WEAK...TO
AROUND 10KT AT BEST...AND WITH A SLIGHTLY STEEPER LAPSE RATE ABOVE
THE INVERSION NOTED ON THE KGSO AND KRNK SOUNDINGS COMPARED TO
KMHX...OVERALL INSTABILITY SHOULD BE GREATER OVER THE NORTHWEST
PIEDMONT DURING THE LATE AFTERNOON. A SMALL CLUSTER OF SHOWERS AND
THUNDERSTORMS WAS LOCATED OVER THE FAR NORTHWEST PART OF THE STATE
EARLY THIS MORNING...AND ANY ASSOCIATED MID-LEVEL VORTICITY WITH
THAT CLUSTER COULD HELP...ALONG WITH THE SURFACE AND 850MB TROUGHS
AND BETTER INSTABILITY...TO GENERATE SCATTERED THUNDERSTORMS
PARTICULARLY IN VICINITY OF THE INTERSTATE 85 CORRIDOR DURING THE
AFTERNOON INTO THE EARLY EVENING. THE LATEST SPC MESOANALYSIS SHOWS
A RELATIVE MAXIMUM OF DOWNDRAFT CAPE OVER CENTRAL NORTH CAROLINA...
TO NEAR 800J/KG...THOUGH SHEAR AND 1000-500MB LAPSE RATES ARE
WEAK...AND WINDS ALOFT SHOULD LIGHTEN SOME...TO VALUES AT 925MB ONLY
NEAR 10 TO 20KT BY 18Z. THE SPC DAY ONE HAS A FIVE PERCENT LINE FOR
SEVERE STORMS FOR WIND MAINLY FROM THE TRIANGLE NORTH...AND IT IS IN
THIS AREA...MAINLY AGAIN ALONG AND NORTH OF INTERSTATE 85...WHERE
HIGHER THETA-E AIR IN COMBINATION WITH SLIGHTLY BETTER LAPSE RATES
COMPARED TO THE REST OF CENTRAL NORTH CAROLINA COULD RESULT IN A
STORM WITH A WIND GUST AROUND 50 MPH. OVER THE FAR EAST AND
SOUTHEAST...SUCH AS EAST OF I-95...THE LATEST RUC SHOWS LIMITED
INSTABILITY AND GREATER MID-LEVEL RIDGING SUCH THAT THE POTENTIAL
FOR SHOWERS AND THUNDERSTORMS SHOULD BE LESSER THERE. ANY SHOWERS
AND THUNDERSTORMS SHOULD TEND TO DIMINISH DIURNALLY. 1000-850MB
THICKNESSES ARE SLIGHTLY REDUCED FROM THOSE FORECAST FRIDAY...AND
WITH THE CLOUDS TO START PULLED BACK A DEGREE OR TWO THE HIGHS IN
THE TRIAD. OVERNIGHT LOWS IN THE LOWER TO MID 70S.
&&
.SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
AS OF 245 AM SATURDAY...
SHORTWAVE ENERGY EMBEDDED IN THE MAIN BELT OF WESTERLIES ALONG THE
US-CANADA BORDER WILL CONTINUE TRACK EAST ACROSS THE NORTHEAST AND
NORTHERN MID-ATLANTIC STATES ON SUNDAY. IT IS BECOMING INCREASINGLY
MORE APPARENT...THAT THE SURFACE FRONTAL ZONE WILL STALL NORTH OF
THE AREA...EXTENDING FROM THE SOUTHERN OHIO VALLEY AND JUST SOUTH OF
THE NATIONS CAPITAL. WITH THE APPRECIABLE FORCING/LIFT REMAINING
NORTH OF THE AREA...LOOKS LIKE CONVECTION WILL STILL HAVE MAINLY A
DIURNAL MODE...INITIALLY FIRING ALONG THE PIEDMONT TROUGH AND
DIFFERENTIAL HEATING OF THE HIGHER TERRAIN ALONG THE MTNS/FTHLS AND
SEABREEZE INTERACTION IN THE EAST. WITH INCREASING PWATS TO OR ABOVE
2.0"...COVERAGE SHOULD BE GREATER THAN THE PAST FEW DAYS...WITH
HIGHEST PROBABILITIES IN THE WEST. AN ISOLATED STRONG TO SEVERE
STORM CANNOT BE RULED OUT GIVEN THE MODERATE TO STRONG
INSTABILITY...BUT WEAK FLOW ALOFT SHOULD LIMIT A MORE ORGANIZED
SEVERE THREAT. ADDITIONALLY...ANY SLOW MOVING OR TRAINING STORMS
COULD RESULT IN LOCALIZED FLOODING.
HIGHS IN THE UPPER 80S TO LOWER 90S. LOWS IN THE LOWER 70S.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 245 AM SATURDAY...
MONDAY AND MONDAY NIGHT:
A BACKDOOR COLD FRONT IS EXPECTED TO STALL OVER VA ON MONDAY WITH
THE H85 TROUGH AXIS EXTENDING EAST THROUGH CENTRAL NC AND THE MAIN
UPPER LEVEL TROUGH OVER THE APPALACHIANS. THE ATMOSPHERE WILL BE
SUFFICIENTLY MOIST AND UNSTABLE TO ALLOW CONVECTION TO DEVELOP
DURING THE AFTERNOON AS WEAK UPPER LEVEL DISTURBANCES MOVE OVER THE
AREA. AHEAD OF THE MAIN TROUGH...THE 00Z GFS SHOWS A H3 SHORTWAVE
DISTURBANCE MOVING NORTHEAST FROM THE LOW OVER LOUISIANA AROUND THE
BASE OF THE TROUGH AND OVER NC MONDAY EVE/NIGHT. DEPENDING ON THE
TIMING...THIS FEATURE COULD ENHANCE CONVECTION LATE MONDAY...OR HELP
SUSTAIN CONVECTION INTO THE OVERNIGHT HOURS. GIVEN THE
UNCERTAINTY...WILL KEEP HIGHEST PRECIP CHANCES DURING THE AFT/EVE
HOURS AND ONLY INCREASE THEM SLIGHTLY DURING THE 03Z-07Z TIMEFRAME.
HIGHS MONDAY STILL EXPECTED TO BE IN THE MID TO UPPER 80S...WITH
OVERNIGHT LOWS MAINLY IN THE LOW TO MID 70S.
TUESDAY THROUGH FRIDAY:
THE UPPER LEVEL TROUGH AXIS SHOULD SHIFT EAST OVER CENTRAL NC ON
TUESDAY WHERE IT WILL LINGER THROUGH FRIDAY. AS THE H85 TROUGH
SLOWLY DRIFTS EAST ON TUESDAY...WINDS OVER THE WESTERN PORTIONS OF
THE AREA MAY SHIFT FROM SOUTHWEST TO MORE WESTERLY. THIS WOULD HELP
DRY OUT THE MID LEVELS A BIT LATE TUESDAY THROUGH WEDNESDAY...THUS
DECREASING PW VALUES SOME. MEANWHILE...THERE IS A DESCENT CHANCE THE
EAST WILL REMAIN UNDER SW FLOW...WITH BETTER MOISTURE ADVECTION AND
GREATER INSTABILITY. MID AND UPPER LEVEL DISTURBANCES MOVING OVER NC
DURING THIS PERIOD WILL LIKELY HELP GENERATE DIURNALLY DRIVEN
CONVECTION. ALTHOUGH GENERALLY CHANCES MAY BE SOMEWHAT BETTER IN THE
EAST...CONFIDENCE WITH REGARD TO LOCATION AND COVERAGE OF THE
CONVECTION REMAINS LOW AT THIS TIME...THUS WILL CARRY CHANCE POPS
DURING THE AFT/EVE ACROSS THE ENTIRE AREA THROUGH THE PERIOD. WILL
CONTINUE THE PERSISTENCE TEMP FORECAST...WITH HIGHS IN THE MID TO
UPPER 80S AND LOWS IN THE LOW TO MID 70S.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 155 PM SATURDAY...
MOSTLY VFR CONDITIONS WILL PREVAIL THROUGH THE EARLY PART OF THE 18Z
VALID TAF PERIOD...AS LINGERING MVFR CEILINGS CONTINUE TO RISE AND
SCATTER EARLY THIS SATURDAY AFTERNOON. IN VICINITY OF THE TRIAD...AND
ALONG THE INTERSTATE 85 CORRIDOR...THERE IS A BETTER CHANCE COMPARED
TO THE REST OF CENTRAL NORTH CAROLINA OF SHOWERS AND THUNDERSTORMS
THIS AFTERNOON INTO THIS EVENING. OVERNIGHT...THE PRIMARY AVIATION
ISSUE WILL BE THE DEVELOPMENT OF LOW CEILINGS. SOME FORECAST
GUIDANCE SUGGESTS THE PROBABILITY OF LOW CLOUDS EARLY SUNDAY TO BE
AT LEAST AS HIGH AS THIS SATURDAY MORNING...AND AS A RESULT
ANTICIPATE FAIRLY WIDESPREAD IFR CONDITIONS AROUND SUNRISE SUNDAY.
CEILINGS SHOULD GRADUALLY RISE INTO MVFR AND LIKELY VFR THROUGH THE
MORNING SUNDAY...BEGINNING AFTER 13Z TO 14Z.
BEYOND THE 18Z VALID TAF PERIOD...A MOIST AIR MASS CONTINUES OVER
CENTRAL NORTH CAROLINA. GIVEN LITTLE AIR MASS CHANGE...AVIATION
INTERESTS SHOULD PREPARE FOR AT LEAST SCATTERED...MAINLY AFTERNOON
AND EVENING SHOWERS AND THUNDERSTORMS EACH DAY...WITH A FEW SHOWERS
AND STORMS POSSIBLY LINGERING THROUGH THE OVERNIGHT HOURS. LATE
NIGHT AND EARLY MORNING FOG WILL HAMPER VISIBILITIES ESPECIALLY
WHERE RAIN TENDS TO CONCENTRATE AND OVERNIGHT WINDS TURN LIGHT.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...CBL/DJF
SHORT TERM...CBL
LONG TERM...KC
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS BISMARCK ND
559 PM CDT SAT JUL 20 2013
.UPDATE...
ISSUED AT 559 PM CDT SAT JUL 20 2013
REGIONAL RADAR IMAGERY SHOWS A COUPLE OF AREAS TO WATCH THIS
EVENING. FIRST IS IN OUR SOUTHWEST...WITH A SEVERE THUNDERSTORM
WATCH BOX UP TO OUR SOUTHWEST BORDER FROM SOUTH DAKOTA.
THUNDERSTORMS CONTINUE TO REMAIN SOUTH OF THE BORDER...BUT COULD
DEVELOP A BIT FURTHER NORTH WITH AN AGITATED CUMULUS FIELD EVIDENT
NEAR BAKER AND ALONG OUR FAR SOUTHWESTERN ZONES. THE OTHER AREA
WAS SEEN OVER NORTHEASTERN MONTANA WITH SEVERE THUNDERSTORMS
ROLLING OUT OF SOUTHERN SASKATCHEWAN AND INTO NORTHERN MONTANA.
WILL CONTINUE TO MONITOR DEVELOPMENT OF THESE THUNDERSTORMS FURTHER
EAST THIS EVENING AND OVERNIGHT...AS WHAT IS BEING INDICATED BY
THE HRRR (HIGH RESOLUTION RAPID REFRESH MODEL)...AS WELL AS THE
OTHER SHORT TERM MODELS.
WARM AIR ADVECTION INCREASES OVERNIGHT AS NAM/GFS SOUNDINGS SHOW
MODERATE VEERING WIND PROFILES FROM THE SFC TO 750MB. EXPECTING AN
INCREASE IN THE AREAL COVERAGE OF SHOWERS/ELEVATED THUNDERSTORMS
THROUGH EARLY SUNDAY MORNING...AS THEY CONTINUE TO DEVELOP ALONG A
WARM FRONT IN EASTERN MONTANA. NAM/GFS SOUNDINGS SHOW DECENT
INSTABILITY/CAPE ABOVE 750MB OVERNIGHT...WITH SHOWALTER INDICES
SHOWING AN INCREASED POTENTIAL FOR ELEVATED THUNDERSTORMS WEST OF
MINOT THROUGH 12Z SUNDAY. THUS WILL CONTINUE TO MENTION ISOLATED
TO SCATTERED THUNDERSTORMS WEST...AND JUST INTO PORTIONS OF
CENTRAL NORTH DAKOTA OVERNIGHT. WILL MONITOR FOR ANY SEVERE
POTENTIAL DURING THE EVENING/OVERNIGHT. MOST OF WESTERN AND
CENTRAL NORTH DAKOTA GET INTO THE WARM SECTOR BY LATE MORNING AND
EARLY AFTERNOON SUNDAY...SETTING THE STAGE FOR SEVERE THUNDERSTORMS
ALONG AND AHEAD OF AN ADVANCING COLD FRONT. SEE PREVIOUS DISCUSSION
BELOW FOR MORE DETAILS.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 310 PM CDT SAT JUL 20 2013
MAIN CONCERNS THIS PERIOD WILL BE THUNDERSTORMS ASSOCIATED WITH A
WARM FRONT EXTENDED ACROSS EASTERN MONTANA THAT IS FORECAST TO
TRACK EAST ACROSS THE STATE LATE TONIGHT AND SUNDAY. SATELLITE
LOOPS SHOW CLOUD COVER ACROSS WESTERN NORTH DAKOTA IN LOW LEVEL
MOIST UP SLOPE FLOW. A BAND OF MID LEVEL SHOWERS AND ISOLATED
THUNDERSTORMS IS MOVING THROUGH SOUTH CENTRAL NORTH DAKOTA. THIS IS
EXPECTED TO DIMINISH AS IT MOVES EAST.
THE FOCUS FOR TONIGHT AND SUNDAY WILL BE THE WARM FRONT IN
EASTERN MONTANA THIS WILL BE PROVIDE LIFT AND WITH A SHORT WAVE
TROUGH SUPPORT THUNDERSTORMS ACROSS THE NORTHWEST...AND THEN THE
NORTH CENTRAL ON SUNDAY. ADDED THE MENTION OF SEVERE WHERE SPC HAS
DEFINED THE SLIGHT RISK SUNDAY AFTERNOON.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 315 PM CDT SAT JUL 20 2013
THE RISK OF SEVERE WEATHER CONTINUES FROM SUNDAY AFTERNOON INTO
THE NIGHT...MAINLY OVER THE CENTRAL AND EASTERN PARTS OF THE
FORECAST AREA.
LONG TERM MODELS ARE IN AGREEMENT THROUGH THE PERIOD ON THE BIG
PICTURE...NAMELY THAT THE H5 RIDGE OFF THE SOUTHWEST COAST BUILDS
EAST INTO THE DESERT SOUTHWEST AND EXPENDS NORTH INTO THE NORTHERN
ROCKIES AND AMPLIFIES. THIS KEEPS A WEAK NORTHWEST FLOW OVER NORTH
DAKOTA WITH CHANCES FOR THUNDERSTORMS COMING AS RIDGE RIDER SHORT
WAVES CREST THE RIDGE AND PASS THROUGH EVERY OTHER DAY. THIS
PATTERN IS ENHANCED AS AN H5 LOW CUTS OFF OVER ONTARIO AND SENDS A
TROUGH AXIS THROUGH DURING THE THURSDAY-FRIDAY TIME FRAME.
THAT...AS INDICATED IN THE PREVIOUS LONG TERM DISCUSSION...WILL BE
THE GREATEST CHANCES FOR STORMS IN THE LONG TERM...AFTER SUNDAY
NIGHT. BUT AGAIN...THERE ARE CHANCES ABOUT EVERY DAY AS TIMING OF
THE WAVES WILL LIKELY CHANGE FROM FORECAST TO FORECAST.
TEMPERATURES SHOULD BE FAIRLY STEADY IN THE PATTERN...AND NOT TOO
FAR FROM NORMAL...GENERALLY IN THE MID 70S NORTHEAST TO MID 80S
SOUTHWEST AND LOWS IN THE 50S TO LOWER 60S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 559 PM CDT SAT JUL 20 2013
LATEST SATELLITE AND RADAR IMAGERY SHOWS SCT/BKN VFR CIGS WITH DRY
CONDITIONS AT THE AERODROMES. AN AREA OF SHOWERS AND THUNDERSTORMS
IN NORTHEASTERN MONTANA WILL BEGIN TO SHIFT EAST OVERNIGHT...PRODUCING
A MENTION FOR PREDOMINANT SHOWERS AND A VCTS AT KMOT/KBIS BY 09Z
SUNDAY. ALTHOUGH VFR CIGS/VSBYS ARE ANTICIPATED NEXT 24HR...ANY OF
THE STRONGER SHOWERS OR THUNDERSTORMS MAY RESULT IN BRIEF PERIODS
OF MVFR/LOW VFR CIGS/VSBYS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...WAA
LONG TERM...JPM
AVIATION...KS
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
449 PM EDT SAT JUL 20 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE SOUTHEAST WILL WEAKEN OVER THE WEEKEND AS
A COLD FRONT MOVES SOUTHWARD FROM THE GREAT LAKES. THE FRONT WILL
STALL NORTH OF THE AREA ON SUNDAY AND THEN DISSIPATE OR RETURN
NORTHWARD INTO MONDAY. AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL
DEVELOP OVER THE EAST ON TUESDAY AND LINGER THROUGH LATE WEEK. A
SECOND WEAK COLD FRONT WILL ARRIVE FROM THE NORTHWEST ON THURSDAY
AND SETTLE JUST SOUTHEAST OF THE REGION THROUGH FRIDAY.
&&
.NEAR TERM /THROUGH SUNDAY/...
400 PM UPDATE...STORMS EXTEND ACRS THE PIEDMONT ATTM...ALIGNED ALONG
MERGED GUST FRONT. SEEMS THERE IS JUST ENOUGH WLY UNIDIRECTIONAL
FLOW TO ALLOW THE STORMS TO ORGANIZE IN THIS WAY. WHILE THE LINE IS
ADVANCING SLOWLY INTO 3000 J/KG SBCAPE IT APPEARS THE GUST FRONT IS
OUTRUNNING IT. DOWNWARD TREND NOTED IN LIGHTNING FREQUENCY WITH
STORMS NEAR NC/SC BORDER. SO THE LINE MAY NOT PERSIST TOO MUCH
LONGER. THIS WOULD AGREE WITH LATEST HRRR ALSO. HOWEVER ISOLATED
CELLS ARE FORMING OVER CHARLOTTE METRO AND THE GUST FRONT MAY KICK
OFF SOME NEW ACTION OVER THE SC PIEDMONT. THUS AMPED UP POPS AHEAD
OF THE LINE DESPITE ITS WEAKENING...MAINTAINING CHANCE POPS N AND W
WHERE REDEVELOPMENT QUITE POSSIBLE. TRIED TO ADJUST TEMP TRENDS
WHICH HAVE BEEN AFFECTED BY THE COOL OUTFLOW...BUT THIS IS DIFFICULT
SO HAVE LOW CONFIDENCE IN TEMP FCST THRU EARLY EVENING.
AT 230 PM EDT SATURDAY...AN UPPER LEVEL TROUGH WILL SLOWLY AMPLIFY
OVER THE EASTERN USA TONIGHT AND SUNDAY. A SHORTWAVE WILL MOVE INTO
THE BASE OF THIS TROUGH OVER THE TN RIVER VALLEY LATE SUNDAY. DEEP
GULF MOISTURE WILL BE TRANSPORTED NORTH INTO OUR AREA BY A GENTLE SW
LOW LEVEL FLOW ON THE WEST SIDE OF A BERMUDA HIGH...WHILE A COLD
FRONT DROPS SOUTH INTO VA. WITH LOW LEVEL FLOW NEARLY PARALLEL THE
TO THE BLUE RIDGE...UPSLOPE FLOW WILL BE LIMITED...THOUGH STILL
PRESENT. WITH THE LOWE LEVELS STABILIZING LATE THIS EVENING...
CONVECTIVE COVER SHOULD DIMINISH. MODEL SOUNDINGS SHOW CAPE
SURPASSING 1000 J/KG AGAIN ON SUNDAY...AND CONVECTIVE TRENDS ARE
EXPECTED TO MIMIC TODAY...WITH THE GREATEST COVERAGE IN THE
MOUNTAINS...WITH ACTIVITY SPREADING EAST INTO THE FOOTHILLS AND
PIEDMONT WITH TIME. SHEAR WILL REMAIN WEAK HOWEVER...LIMITING STORM
ORGANIZATION. MINIMUM TEMPERATURES WILL BE SEVERAL DEGREES ABOVE
NORMAL TONIGHT IN A MOIST AIR MASS. MAXIMUM TEMPERATURES SUNDAY WILL
BE SLIGHTLY BELOW NORMAL...WITH CLOUDS...MOISTURE A FALLING HEIGHTS
ALOFT LIMITING WARMING.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
AT 230 PM SATURDAY... 500 MB HEIGHTS GRADUALLY LOWER OVER THE
SOUTHEAST MONDAY AND TUESDAY BUT SURFACE PATTERN CHANGES WILL BE
RATHER SUBTLE. DIURNAL CONVECTION WILL CONTINUE INTO THE FORECAST
PERIOD BEGINNING 00Z MONDAY THEN GRADUALLY DIMINISH DURING THE
NIGHT. MOIST AND MODERATELY UNSTABLE AIR MASS WILL CONTINUE OVER THE
REGION AND GFS DEPICTS SHORT WAVE TROUGH APPROACHING CWA BY 12Z
MONDAY... SO AT LEAST SLIGHT CHANCE POPS WILL CONTINUE WELL INTO THE
NIGHT. DURING DAYTIME MONDAY... CWA REMAINS IN AIRMASS CONDUCIVE TO
CONVECTIVE STORM DEVELOPMENT SO POPS WILL INCREASE WITH DAYTIME
HEATING INTO CHANCE CATEGORY WITH LIKELY POPS OVER HIGHER TERRAIN.
GFS HAS ANOTHER SHORT WAVE TROUGH DROPPING INTO LONG WAVE TROUGH
POSITION EARLY TUESDAY... SO CHANCE POPS WILL CONTINUE THROUGH THE
NIGHT AND INTO TUESDAY WHEN DIURNAL HEATING CYCLE ONCE AGAIN LEADS
TO HIGHER PROBABILITIES DURING AFTERNOON. NO SIGNIFICANT TEMPERATURE
CHANGES WILL OCCUR DURING MONDAY TUESDAY. HIGHS OUTSIDE THE
MOUNTAINS WILL BE IN THE UPPER 80S AND LOWER 90S WHILE MOUNTAIN
VALLEY TEMPERATURES WILL BE IN THE LOWER TO MIDDLE 80S. VERY WARM
LOW TEMPERATURES IN THE 60S AND LOWER 70S ARE EXPECTED TO CONTINUE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 230 PM SATURDAY... FLOW PATTERN ACROSS U.S. DURING THE PERIOD
WILL CONSIST OF RIDGE IN THE WEST AND TROUGH OVER THE EASTERN
STATES. BOUNDARY LAYER WILL REMAIN WARM AND MOIST SO COOL
TEMPERATURES ALOFT ON WEDNESDAY WILL SUPPORT LAPSE RATES
SUFFICIENTLY STEEP TO PROMOTE CONVECTION WITH APPROACH AND PASSAGE
EARLY THURSDAY OF COLD FRONT. THEREAFTER DETAILS BECOME DIFFICULT TO
RESOLVE AS FRONT DRIFTS SLOWLY SOUTHEAST AND APPEARS IN CURRENT
GUIDANCE TO BECOME NEARLY STATIONARY JUST AFTER CROSSING CWA.
THUS... AIR MASS CHANGE WILL NOT BE SUFFICIENTLY SIGNIFICANT TO
ELIMINATE POPS BUT NUMBERS WILL BE IN THE LOWER END OF THE CHANCE
SPECTRUM AND WILL DISPLAY A DIURNAL TREND. NO SIGNIFICANT CHANGES IN
TEMPERATURE EXPECTED.
&&
.AVIATION /21Z SATURDAY THROUGH THURSDAY/...
AT KCLT /21Z UPDATE/...A BLEND OF MAV AND MET GUIDANCE SUPPORTS MVFR
FOG AT DAYBREAK SUNDAY. GUIDANCE WAS ALL OVER THE PLACE ON CIGS...SO
A NEARLY PERSISTENCE FORECAST WAS USED...TAKING THE CIG DOWN TO THE
LOW END OF MVFR BY DAYBREAK. THUNDERSTORM COVERAGE WARRANTS A
MENTION IN THE TAF THIS AFTERNOON...WITH POSSIBLE MVFR VSBY AND CIG
RESTRICTIONS. DIFFICULT TO TELL AT THIS POINT IF BEST TSTM CHANCES
COME WITH THE LINE SLOWLY PROGRESSING INTO THE PIEDMONT OR FROM
ISOLATED CELLS AHEAD OF IT. WILL EXTEND TEMPO A BIT LATER GIVEN
CURRENT TRENDS. WINDS WILL REMAIN LIGHT FROM THE SW EXCEPT DURING TS
OUTFLOW EFFECTS THIS AFTN...WHICH WILL MOST LIKELY CAUSE A BRIEF
PERIOD OF NW GUSTS UP TO 20-25 KT.
ELSEWHERE...MODEL GUIDANCE IS SUPPORTIVE OF DAYBREAK MVFR FOG SUNDAY
MORNING AT ALL FOOTHILLS SITES EXCEPT KGMU...AND SUPPORTS IFR FOG AT
KAVL. GUIDANCE VARIED WILDLY ON CIGS...SO A NEAR PERSISTENCE
FORECAST WAS USED...TAKING FOOTHILL SITES DOWN TO LOW END MVFR..AND
KAVL BACK DOWN TO LIFR. CONVECTIVE CHANCES SUPPORT CARRYING THUNDER
IN THE TAFS THIS AFTERNOON. LIGHT WINDS WILL PERSIST FROM THE
SW...EXCEPT AT KAVL WHERE THEY WILL VEER TO NW LATE TONIGHT.
OUTLOOK...A COLD FRONT WILL SAG SEWD INTO THE AREA THIS WEEKEND.
EXPECT ABOVE NORMAL TSRA COVERAGE SUNDAY AND INTO EARLY NEXT
WEEK...WITH BEST CHANCES STILL DURING AFTERNOONS AND EVENINGS.
CONFIDENCE TABLE...
20-02Z 02-08Z 08-14Z 14-20Z
KCLT HIGH 100% HIGH 89% MED 69% HIGH 83%
KGSP HIGH 100% HIGH 89% MED 66% HIGH 83%
KAVL HIGH 100% HIGH 89% MED 64% MED 65%
KHKY HIGH 100% HIGH 88% LOW 50% MED 67%
KGMU HIGH 100% HIGH 89% MED 70% MED 67%
KAND HIGH 98% HIGH 88% MED 70% HIGH 83%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...PAT
NEAR TERM...JAT/WIMBERLEY
SHORT TERM...LGL
LONG TERM...LGL
AVIATION...JAT/WIMBERLEY
=
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
319 PM CDT SAT JUL 20 2013
.SHORT TERM...TONIGHT THROUGH MONDAY NIGHT
SEVERAL WEAK SHORT WAVES EMBEDDED WITHIN THE NORTHWEST FLOW ALOFT
WILL BRING ISOLATED TO SCATTERED THUNDERSTORMS ACROSS THE REGION
THIS EVENING THOUGH SUNDAY. WITH HI-RES MODELS STRUGGLING TO
DEPICT THE AREAS OF CONVECTION...WITH MAINTAIN AT LEAST A LOW POP
THROUGH 18Z SUNDAY.
AS OF 19Z...A NARROW LINE OF SHOWERS ARE MOVING SE ACROSS
HYDE/HAND COUNTY. THESE STORMS SHOULD CONTINUE TO DISSIPATE AS THEY
EXIT THIS CWA. FARTHER WEST...A MORE PRONOUNCED SHORT WAVE HAS
CAUSED CONVECTION A DEVELOP OVER THE BLACK HILLS. THIS AREA IS
BASICALLY UNCAPPED WITH SB-CAPE VALUES AROUND 2000 J/KG. THESE
STORMS SHOULD CONTINUE TO GROW AS SOUTH TO EASTERLY LOW LEVEL FLOW
WILL FILTER MOISTURE INTO SW SOUTH DAKOTA. WOULD EXPECT THESE
STORM WILL REMAIN JUST SOUTH OF THE CWA AS THE LAYER STORM MOTION
OFF THE RUC SUGGEST A SE MOTION. THAT SAID...SEVERAL OUTFLOW
BOUNDARIES FROM EARLIER CONVECTION COULD RESULT IN A NORTHWARD
JOG.
CHANCES FOR THUNDERSTORMS IN THE EASTERN CWA TONIGHT/SUNDAY IS A
LITTLE UNCLEAR AT THIS TIME. HALF THE MODEL SUGGEST LLJ INDUCED
THUNDERSTORMS MOVING ACROSS THE EASTERN DAKOTAS BY 12Z. OTHERS
SUGGEST CONVECTION COULD BE SOUTH/EAST/OR NORTH OF THIS CWA. WITH
VERY LOW CONFIDENCE...WILL BROAD BRUSH MOST OF THE CWA WITH LOW
POPS FOR NOW ON SUNDAY.
AN AREA OF LOW PRESSURE AND SURFACE COLD FRONT WILL MOVE ACROSS
THE REGION ON SUNDAY NIGHT/MONDAY MORNING. WITH THE MAJORITY OF
THE PCPN FALLING POST FRONTAL...SEVERE STORMS DO NOT APPEAR
POSSIBLE. COOLER TEMPERATURES ARE EXPECTED ON MONDAY WITH HIGHS IN
THE UPPER 70S..IN THE NE...TO AROUND 90 IN THE SOUTHWEST CWA. A
BLEND OF CONSALL/ALLBLEND SHOWS HIGHS COULD BE SLIGHTLY COOLER
THAN CURRENTLY ADVERTISED.
.LONG TERM...TUESDAY THROUGH SATURDAY
NORTHWEST FLOW ALOFT WILL DOMINATE THROUGH THE EXTENDED. MAIN
FORECAST CHALLENGE WILL BE TIMING SHORTWAVE ACTIVITY. THE PATTERN
WILL REMAIN VERY ACTIVE THROUGH THURSDAY WITH A SERIES OF
SHORTWAVES. TIMING AND INTENSITY ARE VERY DIFFICULT TO DETERMINE
AT THIS TIME RANGE SO CONFIDENCE IN POPS IN ANY GIVEN PERIOD IS
LOW. THAT SAID TUESDAY NIGHT DOES SEEM TO HAVE MODEL AGREEMENT ON
BEING DRY WHILE THURSDAY HAS BEEN CONSISTENTLY STORMY. STUCK CLOSE
TO ALLBLEND POPS BECAUSE OF UNCERTAINTY. BY FRIDAY SFC HIGH
PRESSURE BEGINS TO DROP OUT OF CANADA AND NOSE INTO EASTERN SD.
THE START OF THE WEEKEND APPEARS DRY FOR NOW AS A RESULT.
TEMPERATURES WILL BE MUCH COOLER THROUGH THE PERIOD WITH HIGHS
RANGING FROM THE UPPER 70S IN THE EAST TO THE MID 80S IN THE
SOUTHWEST.
&&
.AVIATION...
18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
VFR CONDITIONS WILL PREVAIL. ISOALTED SHOWERS AND TSTORMS ARE
CONTINUING THIS AFTERNOON BUT HAVE MANAGED TO AVOID THE TAF SITES.
STORMS MAY BECOME MORE WIDESPREAD IN THE WEST THIS EVENING SO LEFT
IN THE VCTS MENTION AT KMBG/KPIR FOR AFTER 00Z. HI-RES MODELS
INDICATE THE EAST MAY SEE AN ISOLATE STORM OR TWO THIS EVENING AS
WELL BUT LOCATION AND TIMING ARE TOO DIFFICULT TO PINPOINT. MAY
NEED TO ADD VCTS AT SOME POINT TO KATY/KABR BUT LEFT OUT FOR NOW.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
SHORT TERM...SD
LONG TERM...WISE
AVIATION...WISE
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
601 PM CDT SAT JUL 20 2013
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND SUNDAY
ISSUED AT 247 PM CDT SAT JUL 20 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A SECONDARY
COLD FRONT STRETCHING FROM CENTRAL NORTH DAKOTA TO PORT WASHINGTON
TO SOUTHERN LOWER MICHIGAN. SEVERAL SHORTWAVES NOTED ON WV IMAGERY
FROM WESTERN WISCONSIN TO NORTH DAKOTA. THE SHORTWAVE OVER WESTERN
WISCONSIN MAY BE HELPING A FEW SHOWERS POP JUST WEST OF THE FOX
VALLEY THIS AFTERNOON EVEN WITHOUT MUCH INSTABILITY AND NORTH OF THE
FRONTAL BOUNDARY. WILL KEEP AN ISOLATED POP MENTION OVER NORTHEAST
WISCONSIN FOR THE REST OF THE AFTERNOON. PRETTY QUIET UPSTREAM UNTIL
YOU REACH THE DAKOTAS. WITH SEVERAL SHORTWAVES TO PASS OVER THE
REGION...SMALL PRECIP CHANCES ARE THE MAIN FORECAST CONCERN.
TONIGHT...LAST NIGHTS COLD FRONT WILL SETTLE FROM THE NORTHERN
PLAINS TO FAR NORTHEAST ILLINOIS. THE 850MB FRONT WILL STALL
FARTHER NORTH OVER CENTRAL WISCONSIN WHERE SEVERAL WEAK RIPPLES
UPSTREAM WILL PASS OVER WITHIN WNW FLOW ALOFT. WEAK FGEN ALSO NOTED
ALONG THE FRONT IN THE MODELS...BUT MODELS ARE ALSO VERY GENEROUS IN
CREATING QPF ALONG THE FRONT TODAY...WHICH HAS NOT VERIFIED WELL.
GIVEN VERY WEAK FORCING AND LITTLE TO NO INSTABILITY TONIGHT...AM
NOT ENTHUSIASTIC ABOUT PRECIP CHANCES AND WILL LEAVE THE FORECAST
AREA DRY TONIGHT EXCEPT FOR VERY LATE WHEN A FEW SPRINKLES OR LIGHT
SHOWERS ARE POSSIBLE OVER CENTRAL WISCONSIN WHERE MOISTURE GETS A
LITTLE MORE DEEPER THAN THE REST OF THE AREA. PLENTY OF MID CLOUDS
UPSTREAM SO INCREASED SKY COVER...AND THEREFORE MIN TEMPS AS WELL.
LOWS FROM THE MID 40S NORTH TO UPPER 50S SOUTH.
SUNDAY...A LITTLE STRONGER SHORTWAVE WILL SWING ACROSS THE NORTHERN
MISSISSIPPI VALLEY AND INTO SOUTHWEST WISCONSIN IN THE AFTERNOON.
FORCING WILL REMAIN ON THE WEAKER SIDE...BUT WILL IMPROVE MARGINALLY
THROUGH THE DAY WITH THE APPROACH OF THE SHORTWAVE. WILL KEEP POPS
WEST OF THE FOX VALLEY AND INCREASE THEM A BIT OVER CENTRAL
WISCONSIN FOR THE AFTERNOON. IF SUFFICIENT BREAKS IN THE CLOUDS
OCCUR SO TEMPS CAN REACH INTO THE MID 70S...CAPES MAY REACH INTO
THE 500-700 J/KG RANGE OVER CENTRAL. SO CANNOT RULE OUT THUNDER
CONSIDERING THUNDERSTORMS ARE OCCURRING UPSTREAM OVER THE PLAINS.
HIGHS IN THE LOW TO MID 70S UNDER PARTLY TO MOSTLY CLOUDY CONDITIONS.
.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY
ISSUED AT 247 PM CDT SAT JUL 20 2013
AREA REMAINS UNDER NW UPPER FLOW DURING THE PERIOD AS SHORTWAVE
TROFS MOVE THROUGH MEAN LONGWAVE TROF OVER E NOAM. STRONGEST OF
THE SHORTWAVES MOVES THROUGH LATE MONDAY. SUFFICIENT INSTABILITY
AND SHEAR FOR THUNDERSTORMS WITH GUSTY WINDS AHEAD OF ASSOCIATED
COLD FRONT LATE MONDAY INTO MONDAY EVENING.
BIGGEST QUESTION IS AMOUNT OF PRECIP IN WAA AHEAD OF THAT SYSTEM.
GFS A BIT MORE AGRESSIVE WITH ELEVATED INSTABILITY AND APPEARS TO
SUFFER FROM SOME CONVECTIVE FEEDBACK OVER S WISC LATE SUNDAY.
REGARDLESS... SCATTERED SHOWERS OR STORMS EXPECTED LATE SUNDAY
ASSOCIATED WITH LIFT IN WAA ZONE.
COOL AIR MOVES INTO REGION BEHIND THE LATE MONDAY COLD FRONT...WITH
LOW TEMPS BY TUE NIGHT FALLING WELL INTO THE 40S ACROSS THE FAR
NORTH. WENT BELOW GUIDANCE MINS FOR THE PERIOD.
TEMP FORECAST FOR THE REMAINDER OF THE PERIOD A BLEND OF BEST
PERFORMING MODEL GUIDANCE. OUTSIDE OF TUE MAX TEMPS...MUCH OF
PERIOD WILL HAVE TEMPS AOB NORMS.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 601 PM CDT SAT JUL 20 2013
MID LEVEL VFR CLOUDS WILL CONTINUE TO PASS OVER THE
AREA TONIGHT INTO SUNDAY. PATCHY MVFR CIGS MAY DEVELOP LATER
SUNDAY AFTERNOON OVER CENTRAL WISCONSIN WITH AREAS OF LIGHT RAIN.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......JKL
AVIATION.......TDH
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND SUNDAY
ISSUED AT 247 PM CDT SAT JUL 20 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A SECONDARY
COLD FRONT STRETCHING FROM CENTRAL NORTH DAKOTA TO PORT WASHINGTON
TO SOUTHERN LOWER MICHIGAN. SEVERAL SHORTWAVES NOTED ON WV IMAGERY
FROM WESTERN WISCONSIN TO NORTH DAKOTA. THE SHORTWAVE OVER WESTERN
WISCONSIN MAY BE HELPING A FEW SHOWERS POP JUST WEST OF THE FOX
VALLEY THIS AFTERNOON EVEN WITHOUT MUCH INSTABILITY AND NORTH OF THE
FRONTAL BOUNDARY. WILL KEEP AN ISOLATED POP MENTION OVER NORTHEAST
WISCONSIN FOR THE REST OF THE AFTERNOON. PRETTY QUIET UPSTREAM UNTIL
YOU REACH THE DAKOTAS. WITH SEVERAL SHORTWAVES TO PASS OVER THE
REGION...SMALL PRECIP CHANCES ARE THE MAIN FORECAST CONCERN.
TONIGHT...LAST NIGHTS COLD FRONT WILL SETTLE FROM THE NORTHERN
PLAINS TO FAR NORTHEAST ILLINOIS. THE 850MB FRONT WILL STALL
FARTHER NORTH OVER CENTRAL WISCONSIN WHERE SEVERAL WEAK RIPPLES
UPSTREAM WILL PASS OVER WITHIN WNW FLOW ALOFT. WEAK FGEN ALSO NOTED
ALONG THE FRONT IN THE MODELS...BUT MODELS ARE ALSO VERY GENEROUS IN
CREATING QPF ALONG THE FRONT TODAY...WHICH HAS NOT VERIFIED WELL.
GIVEN VERY WEAK FORCING AND LITTLE TO NO INSTABILITY TONIGHT...AM
NOT ENTHUSIASTIC ABOUT PRECIP CHANCES AND WILL LEAVE THE FORECAST
AREA DRY TONIGHT EXCEPT FOR VERY LATE WHEN A FEW SPRINKLES OR LIGHT
SHOWERS ARE POSSIBLE OVER CENTRAL WISCONSIN WHERE MOISTURE GETS A
LITTLE MORE DEEPER THAN THE REST OF THE AREA. PLENTY OF MID CLOUDS
UPSTREAM SO INCREASED SKY COVER...AND THEREFORE MIN TEMPS AS WELL.
LOWS FROM THE MID 40S NORTH TO UPPER 50S SOUTH.
SUNDAY...A LITTLE STRONGER SHORTWAVE WILL SWING ACROSS THE NORTHERN
MISSISSIPPI VALLEY AND INTO SOUTHWEST WISCONSIN IN THE AFTERNOON.
FORCING WILL REMAIN ON THE WEAKER SIDE...BUT WILL IMPROVE MARGINALLY
THROUGH THE DAY WITH THE APPROACH OF THE SHORTWAVE. WILL KEEP POPS
WEST OF THE FOX VALLEY AND INCREASE THEM A BIT OVER CENTRAL
WISCONSIN FOR THE AFTERNOON. IF SUFFICIENT BREAKS IN THE CLOUDS
OCCUR SO TEMPS CAN REACH INTO THE MID 70S...CAPES MAY REACH INTO
THE 500-700 J/KG RANGE OVER CENTRAL. SO CANNOT RULE OUT THUNDER
CONSIDERING THUNDERSTORMS ARE OCCURRING UPSTREAM OVER THE PLAINS.
HIGHS IN THE LOW TO MID 70S UNDER PARTLY TO MOSTLY CLOUDY CONDITIONS.
.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY
ISSUED AT 247 PM CDT SAT JUL 20 2013
AREA REMAINS UNDER NW UPPER FLOW DURING THE PERIOD AS SHORTWAVE
TROFS MOVE THROUGH MEAN LONGWAVE TROF OVER E NOAM. STRONGEST OF
THE SHORTWAVES MOVES THROUGH LATE MONDAY. SUFFICIENT INSTABILITY
AND SHEAR FOR THUNDERSTORMS WITH GUSTY WINDS AHEAD OF ASSOCIATED
COLD FRONT LATE MONDAY INTO MONDAY EVENING.
BIGGEST QUESTION IS AMOUNT OF PRECIP IN WAA AHEAD OF THAT SYSTEM.
GFS A BIT MORE AGRESSIVE WITH ELEVATED INSTABILITY AND APPEARS TO
SUFFER FROM SOME CONVECTIVE FEEDBACK OVER S WISC LATE SUNDAY.
REGARDLESS... SCATTERED SHOWERS OR STORMS EXPECTED LATE SUNDAY
ASSOCIATED WITH LIFT IN WAA ZONE.
COOL AIR MOVES INTO REGION BEHIND THE LATE MONDAY COLD FRONT...WITH
LOW TEMPS BY TUE NIGHT FALLING WELL INTO THE 40S ACROSS THE FAR
NORTH. WENT BELOW GUIDANCE MINS FOR THE PERIOD.
TEMP FORECAST FOR THE REMAINDER OF THE PERIOD A BLEND OF BEST
PERFORMING MODEL GUIDANCE. OUTSIDE OF TUE MAX TEMPS...MUCH OF
PERIOD WILL HAVE TEMPS AOB NORMS.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1231 PM CDT SAT JUL 20 2013
MID-LEVEL CLOUDS ALONG A STALLED COLD FRONT WILL GRADUALLY LOWER
OVER THE NEXT 24 HOURS. THINK VFR CONDITIONS WILL HOLD OUT
THOUGH...EVEN IF LIGHT SHOWERS MOVE INTO CENTRAL WISCONSIN
TOMORROW MORNING.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......JKL
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1240 PM CDT SAT JUL 20 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 317 AM CDT SAT JUL 20 2013
CURRENTLY AS OF 08Z...
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED NORTHWEST FLOW
FROM SOUTHWEST CANADA INTO THE GREAT LAKES REGION WITH TROUGHING
CENTERED OVER SOUTHEAST CANADA. NUMEROUS SHORTWAVES WERE PRESENT
WITHIN THE NORTHWEST FLOW...MOST WEAK BUT A FEW WORTH KEYING IN ON.
THE FIRST WAS OVER CENTRAL WISCONSIN WHICH MANAGED TO CARRY SHOWERS
ALMOST INTO TAYLOR AND CLARK COUNTIES BEFORE THEY DISSIPATED. MID
CLOUDS WERE CROSSING TAYLOR/CLARK...THOUGH. A SECOND SHORTWAVE WAS
OVER CENTRAL MN PRODUCING SOME SHOWER ACTIVITY. THIS SHOWER ACTIVITY
TOO WAS DISSIPATING BEING AT THE DAYTIME MINIMUM IN INSTABILITY. THE
THIRD SHORTWAVE OF NOTE...CONVECTIVELY INDUCED AND STILL MAINTAINING
SOME SHOWERS AND THUNDERSTORMS...WAS BACK OVER CENTRAL SOUTH DAKOTA.
DEEP LAYER MOISTURE HAS DEFINITELY DRIED OUT WITH PRECIPITABLE WATER
VALUES FROM 00Z SOUNDINGS RANGING BETWEEN 0.75 AND 1 INCH FROM THE
DAKOTAS INTO THE FORECAST AREA. THIS DRIER AIR HAS KEPT THE FORECAST
AREA OUTSIDE OF THAT CENTRAL WI DRY AND MOSTLY CLEAR OVERNIGHT.
TEMPERATURES WERE MUCH COOLER THIS MORNING THANKS TO THE PASSAGE OF
THE COLD FRONT YESTERDAY...WITH READINGS MAINLY IN THE 60S. 925MB
TEMPS HAVE ALSO COOLED...DOWN TO 22C AT MPX AT 00Z.
SYNOPTIC OVERVIEW...
A NORTHWEST FLOW STAYS IN PLACE ALOFT THROUGH THE SHORT TERM PERIOD.
MUCH OF THE FOCUS IS ON CONVECTIVELY INDUCED SHORTWAVES DEVELOPING
AND RIDING THROUGH THE NORTHWEST FLOW.
TODAY...
ATTENTION IS ON THE SHORTWAVE AND CONVECTION ACROSS CENTRAL SOUTH
DAKOTA. THE 20.00Z NAM REMAINS FAIRLY CONSISTENT IN BRINGING THIS
SHORTWAVE INTO WESTERN PORTIONS OF THE FORECAST AREA THIS AFTERNOON.
CONVECTION CURRENTLY WITH IT MAY EITHER HOLD TOGETHER OR DEVELOP AS
MLCAPE VALUES CLIMB INTO THE 500-1500 J/KG RANGE WITH LITTLE IN THE
WAY OF CIN. ANOTHER POSSIBLE TRIGGER FOR CONVECTION LOOKS TO BE A
LOW PRESSURE TROUGH OVER NORTHERN WI WHICH MODELS DROP DOWN JUST
SOUTH OF I-90 BY 21Z. 0-2KM CONVERGENCE IS VERY WEAK ON THIS
TROUGH...THOUGH. 20.00Z GFS/ECMWF AGREE WITH THE NAM ON THE
POTENTIAL FOR CONVECTIVE ACTIVITY WITH HIGH RESOLUTION MODELS
TENDING TO SUGGEST ISOLATED/SCATTERED CONVECTION. FOLLOWED THE HIGH
RESOLUTION MODELS WITH 20-40 PERCENT CHANCES...HIGHEST WEST OF THE
MS RIVER. IT SHOULD BE NOTED THAT 0-6KM SHEAR IS 40-45 KT...SO IF A
VIGOROUS ENOUGH UPDRAFT CAN FORM...WE COULD SEE A SEVERE STORM.
925MB TEMPS TODAY FROM 20C NORTH TO 23C SOUTH COMBINED WITH SUN
THROUGH ABOUT MID AFTERNOON SUPPORT HIGHS FROM THE MID 70S TO MID
80S.
TONIGHT...
CONVECTION THAT IS AROUND LATE THIS AFTERNOON LOOKS LIKE IT COULD
DIMINISH DURING THE EVENING WITH LOSS OF HEATING. FOCUS THEN TURNS
BACK TO THE WEST WHERE ALL MODELS HAVE BEEN CONSISTENT IN DEVELOPING
A CONVECTIVE SYSTEM AND SHORTWAVE OVER CENTRAL SOUTH DAKOTA INTO
NEBRASKA DURING THE EVENING. AS THIS SHORTWAVE TRACKS SOUTHEAST INTO
IOWA AND KANSAS DURING THE OVERNIGHT HOURS...ALONG WITH THE NORMAL
NOCTURNAL INCREASE IN THE LOW LEVEL JET...850MB MOISTURE TRANSPORT
INCREASES DOWNSTREAM. IT APPEARS THE BIGGER FOCUS FOR PRECIPITATION
WILL END UP BEING ALONG I-70...AROUND THE SAME SPOT WHERE THE COLD
FRONT THAT WENT THROUGH THE AREA YESTERDAY ENDS UP STALLING OUT AT.
HOWEVER...THE 20.00Z NAM/GFS/ECMWF SUGGEST THERE STILL MAY BE ENOUGH
850MB MOISTURE TRANSPORT FORCING FARTHER NORTH TO PRODUCE SOME
SHOWER/STORM ACTIVITY OVER THE FORECAST AREA. ON THE OTHER
HAND...THE 20.00Z REGIONAL CANADIAN KEEPS ANY OF THIS 850MB MOISTURE
TRANSPORT ACTIVITY WELL WEST OF THE AREA BEFORE 12Z SUNDAY. SINCE
THIS REGIONAL CANADIAN SCENARIO IS DEFINITELY PLAUSIBLE...AND HAVING
THE CONCERN FOR CONVECTION TO THE SOUTH...HAVE KEPT CHANCES OF
PRECIPITATION IN THE 20-40 RANGE OVERNIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 317 AM CDT SAT JUL 20 2013
SYNOPTIC OVERVIEW...
20.00Z ECMWF/GFS/CANADIAN CONTINUE TO ADVERTISE THE NORTHWEST FLOW
PATTERN REMAINING IN PLACE THROUGH WEDNESDAY. HEADING INTO THURSDAY
AND FRIDAY...RIDGING STUCK OVER THE WESTERN U.S. MAY TRY TO SHIFT
EAST...BUT AT THE SAME TIME A VIGOROUS TROUGH IS PROGGED TO DROP
INTO NORTHERN ONTARIO AND LAKE SUPERIOR...EFFECTIVELY PREVENTING THE
RIDGE FROM BUILDING UP INTO THE FORECAST AREA.
SUNDAY INTO MONDAY NIGHT...
THE SHORTWAVE TROUGH OVER IOWA AND KS AT 12Z SUNDAY IS PROGGED TO
TRACK EAST THROUGH SOUTHERN SECTIONS OF THE FORECAST AREA LATE
SUNDAY. HARD TO SAY HOW MUCH ACTIVITY THERE MAY BE IN THE MORNING.
HOWEVER...INCREASING DAYTIME INSTABILITY COUPLED WITH THE APPROACH
OF THE SHORTWAVE AND A SURGE OF WARM ADVECTION SHOULD BE ENOUGH TO
PRODUCE SHOWERS AND STORMS OVER MUCH OF THE FORECAST AREA FOR THE
AFTERNOON. 20.00Z GFS/NAM/ECMWF/REGIONAL CANADIAN ALL HAVE PRECIP
FOR THE AFTERNOON...THUS THE 60 PERCENT CHANCES FROM THE PREVIOUS
FORECAST SEEMS REASONABLE. IF MODELS REMAIN CONSISTENT...THESE MAY
NEED TO BE RAISED FURTHER. AS THE SHORTWAVE TROUGH PUSHES EAST
SUNDAY NIGHT AND DIURNAL COOLING HAS ITS INFLUENCE ON THE
CONVECTION...EXPECT THE CONVECTION TO SLIDE EAST AND WEAKEN. DID
LOWER PRECIPITATION CHANCES AFTER MIDNIGHT INTO MONDAY MORNING.
20.00Z ECMWF EVEN SUGGESTS ALL OF SUNDAY NIGHT COULD END UP DRY.
ATTENTION THEN TURNS TO A VIGOROUS SHORTWAVE TROUGH CROSSING FROM
SOUTHERN MANITOBA INTO NORTHERN ONTARIO ON MONDAY. THE ASSOCIATED
COLD FRONT WITH THIS FEATURE LOOKS TO CROSS THE FORECAST AREA LATE
IN THE DAY INTO THE EVENING HOURS. THIS IS VERY GOOD TIMING BECAUSE
IT IS RIGHT AFTER PEAK HEATING. MONDAY SHOULD BE WARM AND HUMID AS
WELL AS SOUTHERLY WINDS AHEAD OF THE FRONT INCREASE TEMPS/DEWPOINTS.
925MB TEMPS CLIMBING TO 22-24C AT 18Z PER 20.00Z ECMWF EASILY BRINGS
HIGHS INTO THE 80S. WOULD NOT BE SURPRISED TO SEE A 90F. THERE ARE
THREE BIG QUESTION MARKS WITH THE FRONT...THOUGH:
1. HOW MUCH FORCING ALOFT WILL THERE BE. MOST MODELS DEPICT ALL THE
MID TO UPPER LEVEL FORCING STAYING TO THE NORTH OF THE AREA.
2. POTENTIAL FOR CAPPING AS A SURGE OF WARMER 800MB AIR FLOWS OUT OF
THE DAKOTAS AND INTO THE FORECAST AREA OVER THE FRONT.
3. 0-2 KM CONVERGENCE ON THE FRONT IS PROGGED TO BE WEAK AT
BEST...PARTIALLY DUE TO THE MID/UPPER FORCING WELL OFF TO THE NORTH.
GIVEN GOOD MODEL SIGNAL FOR PRECIPITATION...HAVE CHANCES IN THE
40-50 RANGE DURING THE FRONTAL PASSAGE. HOWEVER...GIVEN THE
QUESTIONS ABOVE...THE FRONT COULD COME THROUGH DRY OR MAYBE JUST
HAVE ISOLATED STORMS ALONG IT. SHOULD CONVECTION OCCUR...0-3KM SHEAR
VALUES APPROACH 30 KT WHICH COULD SUPPORT ISOLATED DAMAGING WINDS.
CONFIDENCE IS NOT PARTICULARLY HIGH FOR SEVERE...THOUGH.
TUESDAY THROUGH FRIDAY NIGHT...
DESPITE THE NORTHWEST FLOW ALOFT FOR TUESDAY THROUGH THURSDAY...
WHICH LOOKS TO CARRY A VARIETY OF WEAK SHORTWAVES THROUGH THE
FORECAST AREA WITH IT...20.00Z ECMWF/GFS/CANADIAN ARE IN PRETTY GOOD
AGREEMENT ON KEEPING THE FORECAST AREA DRY. THIS IS ALL BECAUSE OF
CANADIAN HIGH PRESSURE BUILDING IN BEHIND THE FRONTAL PASSAGE MONDAY
NIGHT. DRY AIR ASSOCIATED WITH THE HIGH EFFECTIVELY KEEPS THE AREA
DRY. MAY HAVE TO KEEP AN EYE ON THURSDAY FOR POSSIBLE INTRODUCTION
OF PRECIPITATION CHANCES SINCE THE HIGH PRESSURE AREA IS PROGGED TO
SHIFT OFF TO THE EAST. GIVEN THE CANADIAN NATURE OF THE
HIGH...EXPECT COOLER TEMPERATURES...ESPECIALLY COMPARED TO MONDAY.
850MB TEMPS GENERALLY HOVER BETWEEN 10-13C...SUPPORTING HIGHS IN THE
MID 70S TO NEAR 80. THE ECMWF REMAINS VERY CONSISTENT IN SHOWING A
STRONGER SHORTWAVE TRACKING OUT OF NEBRASKA THURSDAY NIGHT AND
HEADING SOUTHEAST INTO IL AND MO FRIDAY NIGHT. THE 20.00Z GFS IS
VERY SIMILAR. IF THESE MODEL SOLUTIONS END UP VERIFYING...AT A
MINIMUM THE SOUTHERN HALF OF THE FORECAST AREA LOOKS FAVORABLE TO
SEE SOME SHOWERS AND STORMS...ESPECIALLY ON FRIDAY. FOLLOWED THE
MODEL CONSENSUS FOR PRECIPITATION CHANCES...IN THE 30-40 RANGE.
ADDITIONALLY...IN THE WAKE OF THIS SHORTWAVE...ANOTHER CANADIAN HIGH
PRESSURE AREA IS AIMED TO DROP SOUTH TOWARDS THE FORECAST AREA FOR
NEXT WEEKEND.
&&
.AVIATION...THROUGH 18Z SUNDAY
1240 PM CDT SAT JUL 20 2013
SOME REMNANT MID-HIGH CLOUD ACROSS THE TAF LOCATIONS AT MID-DAY...
LEFTOVER FROM STORMS THAT FIRED OVER SD. THIS SHOULD CLEAR BY MID-
AFTERNOON. MEANWHILE...ANOTHER BAND OF SHOWERS OVER WESTERN MN ARE
TRACKING THIS WAY. WEAK SHORT WAVE TROUGH ENERGY SEEN IN WATER
VAPOR IMAGERY EXPECTED TO CROSS THE AREA BY EVENING...AND ANOTHER
DISTURBANCE ANTICIPATED OVERNIGHT. SEVERAL WEAK BOUNDARIES LYING
AROUND THE REGION TO ASSIST ON FOCUSING CONVECTIVE POTENTIAL. THE
STRONGEST OF WHICH IS A COOL FRONT ADVANCING SOUTH-SOUTHWEST
ACROSS NORTHERN WI AND CENTRAL MN. EXPECT THE DISTURBANCE THIS
AFTERNOON WILL MAXIMIZE POTENTIAL DURING PEAK HEATING AND COULD
RESULT IN SHOWERS AND ISOLATED THUNDERSTORMS. BETTER CHANCES EXIST
OVER SOUTHEAST MN...BUT EVEN THAT IS REMOTE. THE SECOND WAVE
TONIGHT WILL BRING A BETTER AND MORE WIDESPREAD RISK OF SHRA/TSRA.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...MW
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1144 AM MDT SAT JUL 20 2013
.UPDATE...
ISSUED AT 1041 AM MDT SAT JUL 20 2013
SOME SHOWERS AND THUNDERSTORMS CONTINUE AS OF 16Z OVER THE
NORTHERN PANHANDLE. THE ACTIVITY HAS BEEN MOVING SOUTHEAST AND
SLOWLY DECREASING IN COVERAGE AND INTENSITY. FORECAST FOR THE
AFTERNOON AND EVENING LOOKS TO BE ON TRACK WITH STRONG STORMS
MAINLY EAST OF THE LARAMIE RANGE AND WARMER TEMPERATURES. A
SURFACE BOUNDARY HAS MOVED ACROSS THE CWA TO THE EAST OF THE
LARAMIE RANGE AND WAS POSSIBLY PUSHED SOUTH FROM OUTFLOW FROM
THE ACTIVITY OVER THE NORTH PART OF THE CWA. THE BOUNDARY LOOKS
TO END UP ALONG THE LARAMIE RANGE AND SHOULD PROVIDE THE FOCUS
FOR STORM DEVELOPMENT BY EARLY IN THE AFTERNOON. AS THE STORMS
MOVE OFF THE LARAMIE RANGE...THE ENVIRONMENT WILL BE MOIST AND
UNSTABLE. PRECIPITABLE WATER VALUES WILL BE AROUND AN INCH AND
THE 250MB JET JUST TO THE NORTH OF THE CWA WILL BE PRESENT.
THIS SITUATION IS DIFFERENT THAN IN RECENT WEEKS AND PERHAPS
MORE SIMILAR TO EARLY SUMMER WITH BETTER 0-6KM SHEAR ALLOWING
FOR SUPERCELL DEVELOPMENT. THE STORMS WILL PRODUCE HEAVY RAIN...
HAIL...STRONG WIND GUSTS AND FREQUENT LIGHTNING. SEVERE WEATHER
WILL BE POSSIBLE OVER THE PANHANDLE WITH LARGER HAIL AND WIND
GUST TO 60 MPH. THE HEAVY RAIN WILL CREATE LOCAL AREAS OF
FLOODING. CONSIDERED A FLASH FLOOD WATCH...BUT WILL WAIT UNTIL
AT LEAST STORMS START DEVELOPING. THE STORMS SHOULD BE MOVING
OVER THE SOUTHEAST WYOMING PLAINS EARLY IN THE AFTERNOON AND
BE EAST OF THAT AREA BY LATE AFTERNOON OR EARLY EVENING. THE
ACTIVITY WILL CONTINUE THROUGH AT LEAST THE L;ATE EVENING OVER
THE PANHANDLE.
IN A RECENT UPDATE...BUMPED UP POPS SOME OVER THE EASTERN CWA
AND ADDED THE MENTION OF HEAVY RAIN AND SMALL HAIL OVER THE
SOUTHEAST WYOMING PLAINS.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 230 AM MDT SAT JUL 20 2013
FORECAST CHALLENGES DEAL WITH THUNDERSTORM CHANCES AND SEVERE
POSSIBILITIES THIS AFTERNOON.
CURRENTLY...PRETTY TRANQUIL WEATHER CONDITIONS ACROSS THE CWFA
THIS MORNING SO FAR. HAVE A FRONTAL BOUNDARY ANALYZED FROM KGCC TO
KRWL THIS MORNING ON SURFACE ANALYSIS. SURFACE LOW NEAR RIVERTON.
HAVE ANOTHER COLD FRONT PUSHING SOUTH NEAR BISMARK...EXTENDING
NORTHWEST INTO EASTERN MONTANA. LATEST FORECAST SOUNDINGS SHOWING
A CAPPING INVERSION IN THE LOWER LAYERS NEAR 700MBS. SEEING SOME
LIGHTNING STRIKES OUT NEAR RIVERTON...BUT SO FAR FOR THE CHEYENNE
CWFA...SKIES ARE PRETTY MUCH CLEAR.
SHOULD BEGIN TO SEE AN INCREASE IN SHOWERS AND THUNDERSTORMS LATER
ON TODAY AS THE NORTH DAKOTA COLD FRONT MOVES SOUTH INTO WESTERN
NEBRASKA THIS AFTERNOON. NORTHEAST UPSLOPING WINDS SHOULD HELP US
HERE EAST OF THE LARAMIE RANGE. 700MB CAPPING INVERSION ERODES BY
21Z OR SO WITH CAPES AROUND 1200 J/KG HERE AT CHEYENNE WITH NO
CONVECTIVE INHIBITION. LIFTED INDICES OUT IN THE PANHANDLE DOWN TO
-5C THIS AFTERNOON. CAPES UP TO 2000 J/KG OUT IN THE PANHANDLE. WENT
AHEAD AND INCREASED POPS A LITTLE EAST OF THE LARAMIE RANGE AND IN
THE PANHANDLE FOR THIS AFTERNOON AND ADDED SEVERE THUNDERSTORM
WORDING IN THE FORECAST FOR THE PANHANDLE. A SLIGHT RISK AREA HAS
BEEN ISSUED FOR THE PANHANDLE BY THE STORM PREDICTION CENTER. DAY
SHIFT MAY NEED TO UPDATE THE FORECAST FOR AREAS IN SOUTHEAST
WYOMING EAST OF THE LARAMIE RANGE BASED ON RADAR TRENDS LATER
TODAY. LATEST HRRR COMPOSITE REFLECTIVITY HAS THUNDERSTORMS
FORMING OVER THE LARAMIE RANGE AROUND 18Z...DRIFTING EASTWARD
TOWARDS THE PANHANDLE DURING THE AFTERNOON HOURS. STORMS ARE GOING
TO BE SLOW MOVING WITH STORM MOTION FORECASTS FROM THE NORTHWEST
UNDER 10KTS...SO THOSE FORTUNATE ENOUGH TO BE UNDER ONE OF THESE
STORMS SHOULD SEE QUITE A BIT OF RAINFALL. NAM PRECIPITABLE WATER
FORECASTS AROUND .9 INCHES HERE AT CHEYENNE AND 1.1 INCHES OUT
IN THE PANHANDLE. WITH RECENT RAINS OUT IN THE PANHANDLE...A FLASH
FLOOD THREAT COULD EXIST AS WELL. DAY SHIFT WILL NEED TO WATCH
THIS CLOSELY.
FRONTAL BOUNDARY SHIFTS EAST INTO CENTRAL NEBRASKA THIS EVENING
WITH SHOWERS AND THUNDERSTORMS COMING TO AN END TOWARDS MIDNIGHT.
SUNDAY LOOKS MAINLY DRY WEST OF THE LARAMIE RANGE AS AN UPPER
LEVEL RIDGE BUILDS INTO THE AREA. BEST CHANCES FOR SHOWERS AND
THUNDERSTORMS CONTINUES TO BE THE PANHANDLE AS THEY STAY IN THE
SOUTHEAST LOW LEVEL WIND FLOW THROUGH THE AFTERNOON. GFS AND ECMWF
SIMILAR ON QPF PLACEMENT FOR SUNDAY...SO KEPT CHANCE POPS GOING
EAST OF THE LARAMIE RANGE.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 111 AM MDT SAT JUL 20 2013
MEDIUM RANGE MODELS SHOW DRIER AIR PUSHING ACROSS SOUTHEAST
WYOMING AND INTO PORTIONS OF WESTERN NEBRASKA ON TUESDAY. UPPER
LEVEL HIGH PRESSURE WHICH HAS ESTABLISHED ITSELF ACROSS THE
WESTERN THIRD OF THE UNITED STATES MOST OF THIS SUMMER...WILL
DRIFT EAST OVER THE CENTRAL ROCKIES AND BUILD NORTHWARD. MIDLEVEL
SUBSIDENCE AND DRY NORTHWEST FLOW ALOFT WILL REDUCE CONVECTIVE
DEVELOPMENT ON TUESDAY...ALTHOUGH IT WILL BE RATHER MOIST NEAR THE
SURFACE ACROSS WESTERN NEBRASKA WHERE DEWPOINTS WILL REMAIN IN THE
50 TO 60 DEGREE RANGE WITH UPSLOPE EASTERLY WINDS. HIGH
TEMPERATURES IN THE 90S ARE EXPECTED ACROSS MOST OF THE FORECAST
AREA ON TUESDAY.
FOR THE MIDDLE OF THE WEEK...MODELS SHOW THE UPPER LEVEL FLOW
TRANSITIONING TO A MORE ZONAL PATTERN AS A FEW UPPER LEVEL
SHORTWAVES PUSH ACROSS THE NORTHERN AND CENTRAL ROCKIES. EXPECT
SLIGHTLY COOLER TEMPERATURES EACH DAY AND A HIGHER CHANCE OF
SHOWERS AND THUNDERSTORMS RETURNING TO THE REGION. WEDNESDAY
AFTERNOON IS TRICKY IN TERMS OF TSTORM CHANCES...WITH MODEL
SOUNDINGS SHOWING A CAPPED ENVIRONMENT WITH A WARM LAYER JUST
ABOVE 700MB. SOUNDINGS SHOW PW/S OVER 1 INCH AND CAPE OF 2500 J/KG
WITH BREEZY SOUTHEAST WINDS. NOT COMFORTABLE WITH POP BELOW 15
PERCENT NEAR THE MOUNTAINS...SO INCREASED POP AND ADDED A SLIGHT
CHANCE OF TSTORMS TO THE HIGH PLAINS ADJACENT OF THE LARAMIE
RANGE. CIN VALUES ARE BETWEEN -20 TO -50 J/KG IN THESE LOCATIONS
WHICH IS NOT QUITE ENOUGH TO PREVENT ISOLATED CONVECTION. ACROSS
THE PANHANDLE...CIN VALUES ARE OVER -200 J/KG WHICH SHOULD KEEP
THOSE AREAS DRY...AT LEAST INTO WEDNESDAY NIGHT. SCATTERED SHOWERS
AND TSTORMS WILL LIKELY RETURN TO ALL OF SOUTHEAST WYOMING AND
WESTERN NEBRASKA ON THURSDAY AS A VIGOROUS SHORT WAVE PUSHES
ACROSS THE AREA. FRIDAY WILL CONTINUE THIS TREND WITH COOLER
TEMPERATURES LOWERING INTO THE UPPER 70S TO LOW 80S FOR HIGHS WITH
WIDELY SCATTERED/SCATTERED TSTORMS POSSIBLE IN THE AFTERNOON AND
EVENING HOURS. WITH SUBTROPICAL MOISTURE FLOWING NORTHWARD...WILL
HAVE TO KEEP AN EYE ON FLASH FLOODING BY LATE NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY MORNING)
ISSUED AT 1144 AM MDT SAT JUL 20 2013
MAIN AVIATION IMPACT WILL BE THE THREAT FOR SHOWERS AND
THUNDERSTORMS AND RESULTANT MVFR VSBYS THIS AFTERNOON AND
EVENING. THIS WILL ESPECIALLY BE THE CASE FOR TERMINALS TO THE
EAST OF THE LARAMIE RANGE WHERE THE ATMOSPHERE WILL BE MOST
FAVORABLE. AS OF 1745Z...CONVECTION HAS JUST BEGAN TO DEVELOP OFF
THE SOUTHEAST WYOMING MOUNTAINS. THIS TREND WILL CONTINUE AS
THUNDERSTORMS BECOME MORE NUMEROUS THIS AFTERNOON. THESE
THUNDERSTORMS ARE NOT ANTICIPATED TO AFFECT AIRFIELDS UNTIL AFTER
20Z OR 21Z. COVERAGE WILL BE SUFFICIENT ENOUGH TO INCLUDE A TEMPO
GROUP AT MOST SITES. SHOWERS AND THUNDERSTORMS WILL LIKELY PUSH
SOUTH AND EAST OF THE AIRFIELDS BY 02Z OR 03Z...WITH GRADUAL
IMPROVEMENT ANTICIPATED THEREAFTER. A FEW OF THE STRONGEST
THUNDERSTORMS MAY CONTAIN LARGE HAIL AND DAMAGING WINDS...
ESPECIALLY AT WESTERN NEBRASKA PANHANDLE SITES.
&&
.FIRE WEATHER...
ISSUED AT 230 AM MDT SAT JUL 20 2013
ANOTHER CHANCE FOR WETTING RAINS MAINLY IN THE PANHANDLE AND EAST
OF THE LARAMIE RANGE THIS AFTERNOON. EASTERLY WINDS WILL BE LIGHT
TODAY AND ARE EXPECTED TO REMAIN LIGHT FROM THE EAST THROUGH
SUNDAY. DRIER CONDITIONS RETURN SUNDAY INTO NEXT WEEK AS HIGH
PRESSURE BUILDS INTO COLORADO. WE COULD BE LOOKING AT ELEVATED TO
CRITICAL FIRE WEATHER CONDITIONS TUESDAY AS WINDS INCREASE INTO
THE 25 TO 35 MPH RANGE. THIS IS DUE TO A LOW PRESSURE SYSTEM
MOVING THROUGH NORTHERN WYOMING AND MONTANA TUESDAY AFTERNOON.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...WEILAND
SHORT TERM...CLAYCOMB
LONG TERM...TJT
AVIATION...HAHN
FIRE WEATHER...CLAYCOMB
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1041 AM MDT SAT JUL 20 2013
.UPDATE...
ISSUED AT 1041 AM MDT SAT JUL 20 2013
SOME SHOWERS AND THUNDERSTORMS CONRINUE AS OF 16Z OVER THE
NORTHERN PANHANDLE. THE ACTIVITY HAS BEEN MOVING SOUTHEAST AND
SLOWLY DECREASING IN COVERAGE AND INTENSITY. FORECAST FOR THE
AFTERNOON AND EVENING LOOKS TO BE ON TRACK WITH STRONG STORMS
MAINLY EAST OF THE LARAMIE RANGE AND WARMER TEMPERATURES. A
SURFACE BOUNDARY HAS MOVED ACROSS THE CWA TO THE EAST OF THE
LARAMIE RANGE AND WAS POSSIBLY PUSHED SOUTH FROM OUTFLOW FROM
THE ACTIVITY OVER THE NORTH PART OF THE CWA. THE BOUNDARY LOOKS
TO END UP ALONG THE LARAMIE RANGE AND SHOULD PROVIDE THE FOCUS
FOR STORM DEVELOPMENT BY EARLY IN THE AFTERNOON. AS THE STORMS
MOVE OFF THE LARAMIE RANGE...THE ENVIRONMENT WILL BE MOIST AND
UNSTABLE. PRECIPITABLE WATER VALUES WILL BE AROUND AN INCH AND
THE 250MB JET JUST TO THE NORTH OF THE CWA WILL BE PRESENT.
THIS SITUATION IS DIFFERENT THAN IN RECENT WEEKS AND PERHAPS
MORE SIMILAR TO EARLY SUMMER WITH BETTER 0-6KM SHEAR ALLOWING
FOR SUPERCELL DEVELOPMENT. THE STORMS WILL PRODUCE HEAVY RAIN...
HAIL...STRONG WIND GUSTS AND FREQUENT LIGHTNING. SEVERE WEATHER
WILL BE POSSIBLE OVER THE PANHANDLE WITH LARGER HAIL AND WIND
GUST TO 60 MPH. THE HEAVY RAIN WILL CREATE LOCAL AREAS OF
FLOODING. CONSIDERED A FLASH FLOOD WATCH...BUT WILL WAIT UNTIL
AT LEAST STORMS START DEVELOPING. THE STORMS SHOULD BE MOVING
OVER THE SOUTHEAST WYOMING PLAINS EARLY IN THE AFTERNOON AND
BE EAST OF THAT AREA BY LATE AFTERNOON OR EARLY EVENING. THE
ACTIVITY WILL CONTINUE THROUGH AT LEAST THE L;ATE EVENING OVER
THE PANHANDLE.
IN A RECENT UPDATE...BUMPED UP POPS SOME OVER THE EASTERN CWA
AND ADDED THE MENTION OF HEAVY RAIN AND SMALL HAIL OVER THE
SOUTHEAST WYOMING PLAINS.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 230 AM MDT SAT JUL 20 2013
FORECAST CHALLENGES DEAL WITH THUNDERSTORM CHANCES AND SEVERE
POSSIBILITIES THIS AFTERNOON.
CURRENTLY...PRETTY TRANQUIL WEATHER CONDITIONS ACROSS THE CWFA
THIS MORNING SO FAR. HAVE A FRONTAL BOUNDARY ANALYZED FROM KGCC TO
KRWL THIS MORNING ON SURFACE ANALYSIS. SURFACE LOW NEAR RIVERTON.
HAVE ANOTHER COLD FRONT PUSHING SOUTH NEAR BISMARK...EXTENDING
NORTHWEST INTO EASTERN MONTANA. LATEST FORECAST SOUNDINGS SHOWING
A CAPPING INVERSION IN THE LOWER LAYERS NEAR 700MBS. SEEING SOME
LIGHTNING STRIKES OUT NEAR RIVERTON...BUT SO FAR FOR THE CHEYENNE
CWFA...SKIES ARE PRETTY MUCH CLEAR.
SHOULD BEGIN TO SEE AN INCREASE IN SHOWERS AND THUNDERSTORMS LATER
ON TODAY AS THE NORTH DAKOTA COLD FRONT MOVES SOUTH INTO WESTERN
NEBRASKA THIS AFTERNOON. NORTHEAST UPSLOPING WINDS SHOULD HELP US
HERE EAST OF THE LARAMIE RANGE. 700MB CAPPING INVERSION ERODES BY
21Z OR SO WITH CAPES AROUND 1200 J/KG HERE AT CHEYENNE WITH NO
CONVECTIVE INHIBITION. LIFTED INDICES OUT IN THE PANHANDLE DOWN TO
-5C THIS AFTERNOON. CAPES UP TO 2000 J/KG OUT IN THE PANHANDLE. WENT
AHEAD AND INCREASED POPS A LITTLE EAST OF THE LARAMIE RANGE AND IN
THE PANHANDLE FOR THIS AFTERNOON AND ADDED SEVERE THUNDERSTORM
WORDING IN THE FORECAST FOR THE PANHANDLE. A SLIGHT RISK AREA HAS
BEEN ISSUED FOR THE PANHANDLE BY THE STORM PREDICTION CENTER. DAY
SHIFT MAY NEED TO UPDATE THE FORECAST FOR AREAS IN SOUTHEAST
WYOMING EAST OF THE LARAMIE RANGE BASED ON RADAR TRENDS LATER
TODAY. LATEST HRRR COMPOSITE REFLECTIVITY HAS THUNDERSTORMS
FORMING OVER THE LARAMIE RANGE AROUND 18Z...DRIFTING EASTWARD
TOWARDS THE PANHANDLE DURING THE AFTERNOON HOURS. STORMS ARE GOING
TO BE SLOW MOVING WITH STORM MOTION FORECASTS FROM THE NORTHWEST
UNDER 10KTS...SO THOSE FORTUNATE ENOUGH TO BE UNDER ONE OF THESE
STORMS SHOULD SEE QUITE A BIT OF RAINFALL. NAM PRECIPITABLE WATER
FORECASTS AROUND .9 INCHES HERE AT CHEYENNE AND 1.1 INCHES OUT
IN THE PANHANDLE. WITH RECENT RAINS OUT IN THE PANHANDLE...A FLASH
FLOOD THREAT COULD EXIST AS WELL. DAY SHIFT WILL NEED TO WATCH
THIS CLOSELY.
FRONTAL BOUNDARY SHIFTS EAST INTO CENTRAL NEBRASKA THIS EVENING
WITH SHOWERS AND THUNDERSTORMS COMING TO AN END TOWARDS MIDNIGHT.
SUNDAY LOOKS MAINLY DRY WEST OF THE LARAMIE RANGE AS AN UPPER
LEVEL RIDGE BUILDS INTO THE AREA. BEST CHANCES FOR SHOWERS AND
THUNDERSTORMS CONTINUES TO BE THE PANHANDLE AS THEY STAY IN THE
SOUTHEAST LOW LEVEL WIND FLOW THROUGH THE AFTERNOON. GFS AND ECMWF
SIMILAR ON QPF PLACEMENT FOR SUNDAY...SO KEPT CHANCE POPS GOING
EAST OF THE LARAMIE RANGE.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 111 AM MDT SAT JUL 20 2013
MEDIUM RANGE MODELS SHOW DRIER AIR PUSHING ACROSS SOUTHEAST
WYOMING AND INTO PORTIONS OF WESTERN NEBRASKA ON TUESDAY. UPPER
LEVEL HIGH PRESSURE WHICH HAS ESTABLISHED ITSELF ACROSS THE
WESTERN THIRD OF THE UNITED STATES MOST OF THIS SUMMER...WILL
DRIFT EAST OVER THE CENTRAL ROCKIES AND BUILD NORTHWARD. MIDLEVEL
SUBSIDENCE AND DRY NORTHWEST FLOW ALOFT WILL REDUCE CONVECTIVE
DEVELOPMENT ON TUESDAY...ALTHOUGH IT WILL BE RATHER MOIST NEAR THE
SURFACE ACROSS WESTERN NEBRASKA WHERE DEWPOINTS WILL REMAIN IN THE
50 TO 60 DEGREE RANGE WITH UPSLOPE EASTERLY WINDS. HIGH
TEMPERATURES IN THE 90S ARE EXPECTED ACROSS MOST OF THE FORECAST
AREA ON TUESDAY.
FOR THE MIDDLE OF THE WEEK...MODELS SHOW THE UPPER LEVEL FLOW
TRANSITIONING TO A MORE ZONAL PATTERN AS A FEW UPPER LEVEL
SHORTWAVES PUSH ACROSS THE NORTHERN AND CENTRAL ROCKIES. EXPECT
SLIGHTLY COOLER TEMPERATURES EACH DAY AND A HIGHER CHANCE OF
SHOWERS AND THUNDERSTORMS RETURNING TO THE REGION. WEDNESDAY
AFTERNOON IS TRICKY IN TERMS OF TSTORM CHANCES...WITH MODEL
SOUNDINGS SHOWING A CAPPED ENVIRONMENT WITH A WARM LAYER JUST
ABOVE 700MB. SOUNDINGS SHOW PW/S OVER 1 INCH AND CAPE OF 2500 J/KG
WITH BREEZY SOUTHEAST WINDS. NOT COMFORTABLE WITH POP BELOW 15
PERCENT NEAR THE MOUNTAINS...SO INCREASED POP AND ADDED A SLIGHT
CHANCE OF TSTORMS TO THE HIGH PLAINS ADJACENT OF THE LARAMIE
RANGE. CIN VALUES ARE BETWEEN -20 TO -50 J/KG IN THESE LOCATIONS
WHICH IS NOT QUITE ENOUGH TO PREVENT ISOLATED CONVECTION. ACROSS
THE PANHANDLE...CIN VALUES ARE OVER -200 J/KG WHICH SHOULD KEEP
THOSE AREAS DRY...AT LEAST INTO WEDNESDAY NIGHT. SCATTERED SHOWERS
AND TSTORMS WILL LIKELY RETURN TO ALL OF SOUTHEAST WYOMING AND
WESTERN NEBRASKA ON THURSDAY AS A VIGOROUS SHORT WAVE PUSHES
ACROSS THE AREA. FRIDAY WILL CONTINUE THIS TREND WITH COOLER
TEMPERATURES LOWERING INTO THE UPPER 70S TO LOW 80S FOR HIGHS WITH
WIDELY SCATTERED/SCATTERED TSTORMS POSSIBLE IN THE AFTERNOON AND
EVENING HOURS. WITH SUBTROPICAL MOISTURE FLOWING NORTHWARD...WILL
HAVE TO KEEP AN EYE ON FLASH FLOODING BY LATE NEXT WEEK.
&&
.AVIATION...(FOR THE 12Z TAF ISSUANCE)
VFR CONDITIONS WILL PREVAIL THIS MORNING THROUGH 18Z. SURFACE WINDS
WILL BE VARIABLE AT 10 KT OR LESS WITH CLEAR SKIES. THERE IS A
BETTER CHANCE OF THUNDERSTORMS FOR TERMINALS ACROSS THE HIGH PLAINS
INTO WESTERN NEBRASKA THIS AFTERNOON...MAINLY EAST OF THE LARAMIE
RANGE. STRONG GUSTY WINDS...FREQUENT LIGHTNING...AND SMALL HAIL WILL
BE THE MAIN CONCERNS WITH THESE THUNDERSTORMS THROUGH THIS EVENING.
&&
.FIRE WEATHER...
ISSUED AT 230 AM MDT SAT JUL 20 2013
ANOTHER CHANCE FOR WETTING RAINS MAINLY IN THE PANHANDLE AND EAST
OF THE LARAMIE RANGE THIS AFTERNOON. EASTERLY WINDS WILL BE LIGHT
TODAY AND ARE EXPECTED TO REMAIN LIGHT FROM THE EAST THROUGH
SUNDAY. DRIER CONDITIONS RETURN SUNDAY INTO NEXT WEEK AS HIGH
PRESSURE BUILDS INTO COLORADO. WE COULD BE LOOKING AT ELEVATED TO
CRITICAL FIRE WEATHER CONDITIONS TUESDAY AS WINDS INCREASE INTO
THE 25 TO 35 MPH RANGE. THIS IS DUE TO A LOW PRESSURE SYSTEM
MOVING THROUGH NORTHERN WYOMING AND MONTANA TUESDAY AFTERNOON.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...WEILAND
SHORT TERM...CLAYCOMB
LONG TERM...TJT
AVIATION...TJT
FIRE WEATHER...CLAYCOMB