Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 07/21/13
AREA FORECAST DISCUSSION
NWS TUCSON AZ
900 PM MST SAT JUL 20 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...AFTER AN ACTIVE AND WET AFTERNOON...ACTIVITY ACROSS
SOUTHEAST ARIZONA HAS DIMINISHED A BIT. HOWEVER...THE ATMOSPHERE IS
STILL VERY MOIST AND WITH THE REMNANT OUTFLOW BOUNDARIES FLOATING
AROUND...THERE IS STILL SOME POTENTIAL FOR ISOLATED CONVECTION
THROUGH THE OVERNIGHT HOURS. IN FACT...DYING STORMS IN WESTERN NEW
MEXICO PUSHED OUT A BOUNDARY THAT IS HEADING INTO THE
GREENLEE/COCHISE COUNTY AREA AND MAY TRIGGER STORMS IN THE NEXT FEW
HOURS. PLUS...WE STILL HAVE OUR UPPER LOW CHURNING TO THE SW...SO
THE BEST LIFT WILL OCCUR OVER OUR WESTER ZONES.
THE HRRR KEEPS US ON THE QUIET SIDE THROUGH THE REST OF THE EVENING
AND THIS DOES MAKE SENSE GIVE THE POST STORM STABLE ATMOSPHERE IN
PLACE. SO THE BIG QUESTION IS WHETHER OR NOR THE REMNANT BOUNDARIES
CAN OVERCOME THE STABLE ATMOSPHERE TO PRODUCE CONVECTION.
WITH ALL THAT IN MIND...I WILL INCREASE POPS TO THE CHANCE RANGE IN
WESTERN PIMA AND KEEP THE CHANCE POPS ACROSS THE REST OF THE CWA.
THERE IS STILL SOME POTENTIAL FOR HEAVY RAIN OVERNIGHT AND GIVEN THE
WET GROUND IN PLACE...WE WILL NEED TO WATCH THE FLOOD THREAT.
JJB
&&
.AVIATION...SCATTERED TO NUMEROUS SHRA/TSRA WILL CONTINUE INTO THE
EVENING...BECOMING MORE ISOLATED AFT 21/03Z. EXPECT MVFR CIGS AND
VSBYS WITH BRIEF WIND GUSTS UP TO 40 KTS WITH THE STRONGER TSRA.
CONDITIONS SCT-BKN060 SCT-BKN100 BKN250 THEN AFT 21/08Z SCT060
SCT-BKN100. SURFACE WIND DIURNAL IN DIRECTION AND GENERALLY LESS
THAN 10 KTS THRU SUNDAY. AVIATION DISCUSSION NOT UPDATED FOR TAF
AMENDMENTS. CERNIGLIA
&&
.FIRE WEATHER...AN UPPER LOW OVER THE NORTHERN GULF OF CALIFORNIA
WILL CONTINUE TO PUMP MOISTURE OVER SOUTHERN ARIZONA THROUGH SUNDAY
AS IT SLOWLY MOVES WEST. THIS MOISTURE AND THE RESULTANT
INSTABILITY WILL BRING ABOUT PLENTY OF CONVECTION THROUGH SUNDAY
EVENING. THE STRONGER THUNDERSTORMS WILL BE CAPABLE OF PRODUCING
HEAVY DOWNPOURS DUE TO THE ABUNDANT MOISTURE AS WELL AS GUSTY AND
ERRATIC WINDS. NORMAL DIURNAL WIND PATTERNS ARE EXPECTED OVER THE
NEXT SEVERAL DAYS...HOWEVER THEY WILL BE DISRUPTED AT TIMES DUE TO
STORM OUTFLOWS. THE SHOWERS AND THUNDERSTORMS WILL BECOME LESS
NUMEROUS AND MORE LIMITED TO THE AFTERNOON AND EVENING HOURS MONDAY
AND TUESDAY AS THE LOW MOVES FURTHER WEST AND THE AIR MASS BECOMES A
BIT DRIER OVER THE REGION. ANOTHER EASTERLY WAVE WILL ENHANCE THE
CONVECTION ACROSS SOUTHERN ARIZONA WEDNESDAY AND THURSDAY AS IT
PASSES BY TO THE SOUTH. CERNIGLIA
&&
.PREV DISCUSSION...THE UPPER LOW SPINNING OVER THE GULF OF
CALIFORNIA WAS HELPING TRIGGER SCATTERED SHOWERS AND THUNDERSTORMS
EARLY THIS AFTERNOON. THE STEERING FLOW WAS TRACKING THIS ACTIVITY
WESTWARD AT 15 MPH...WITH A FEW OF THE STRONGER THUNDERSTORMS
PRODUCING RAINFALL AMOUNTS OF ONE-HALF OF INCH IN 15 TO 30 MINUTES.
THAT SAID...THESE RAINFALL RATES CAN CAUSE MINOR FLOODING IN POOR
DRAINAGE AREAS AND RAPID RUNOFF INTO NORMALLY DRY WASHES. THE
STRONGEST STORMS COULD PRODUCE HIGH WINDS...BUT FLASH FLOODING WILL
BE THE PRIMARY THREAT FROM THESE STORMS TODAY.
THE UPPER LOW OVER THE GULF OF CALIFORNIA TODAY WILL TRACK THROUGH
SOUTHERN CALIFORNIA AND WEAKEN SUNDAY INTO MONDAY. WILL SEE ANOTHER
ACTIVE THUNDERSTORM DAY TOMORROW BEFORE DRIER AIR SPREADS IN BEHIND
THE UPPER LOW ON MONDAY. THEREAFTER...HIGH PRESSURE ALOFT BECOMES
CENTERED NEAR THE FOUR CORNERS REGION AROUND TUESDAY AND WEDNESDAY.
OVERALL...THE PATTERN APPEARED FAVORABLE FOR DAILY THUNDERSTORM
ACTIVITY THROUGH AT LEAST FRIDAY.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS PUEBLO CO
313 PM MDT FRI JUL 19 2013
.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...
FLASH FLOOD WATCH UNTIL 10 PM MDT THIS EVENING FOR COZ081-082-
084-085.
&&
$$
SHORT TERM...28
LONG TERM...PETERSEN
AVIATION...28
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
309 PM MDT FRI JUL 19 2013
.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. DEWPOINTS 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 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 308 PM MDT FRI JUL 19 2013
SIMILAR TO YESTERDAY...SCATTERED SHOWERS AND THUNDERSTORMS MAINLY
ACROSS THE CENTRAL AND SOUTH LATE TONIGHT WILL BECOME MORE NUMEROUS
BY 00Z BEFORE DECREASING IN COVERAGE BY 06Z. HEAVY RAIN FROM THE
STRONGER STORMS WILL CREATE PERIODS OF MVFR OR EVEN IFR VISIBILITY
AT TIMES...WITH MOUNTAIN OBSCURATIONS. KVEL IS THE TAF SITE LEAST
LIKELY TO BE AFFECTED.
DRIER AIR WORKS IN FROM THE NW LATE TONIGHT AND SATURDAY CONFINING
CONVECTIVE ACTIVITY MAINLY SOUTH OF I-70 AFTER 18Z SATURDAY. VFR SHOULD
BE THE PREVAILING FLIGHT CONDITION AT ALL TAF SITES ON SATURDAY.
&&
.HYDROLOGY...
ISSUED AT 308 PM MDT FRI JUL 19 2013
THE FLASH FLOOD WATCH CONTINUES FOR MUCH OF THE FORECAST AREA. WILL
BE MONITORING STORMS CLOSELY ONCE THEY DEVELOP FOR THE POTENTIAL OF
EXCESSIVE RAINFALL/RUNOFF. SOME AREAS THAT MAY BE MORE PRONE TO
RUNOFF PROBLEMS WILL BE THOSE LOCATIONS THAT HAVE ALREADY RECEIVED
HEAVIER RAIN. BURN SCARS WILL LITTLE OR NO REGROWTH WILL BE
ESPECIALLY SUSCEPTIBLE TO ASH AND DEBRIS/MUD FLOW IN HEAVY RAIN. THE
THREAT OF HEAVY RAIN AND FLASH FLOODING DECREASES THIS WEEKEND.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...FLASH FLOOD WATCH UNTIL MIDNIGHT MDT TONIGHT FOR COZ001>003-
006>014-017>023.
UT...FLASH FLOOD WATCH UNTIL MIDNIGHT MDT TONIGHT FOR UTZ022-025-
027>029.
&&
$$
SHORT TERM...JAD
LONG TERM...JOE
AVIATION...JAD
HYDROLOGY...JAD
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1008 AM MDT FRI JUL 19 2013
.UPDATE...ONLY MINOR ADJUSTMENTS AT THIS TIME. SHOWERS AND TSTMS
OVER THE NORTHEAST PLAINS THIS MORNING WILL PERSIST INTO THE EARLY
AFTERNOON....WITH SHOWERS AND THUNDERSTORMS DEVELOPING OVER THE
MOUNTAINS AND FOOTHILLS AROUND 18Z. HRRR RUNS OFFERING DIFFERING
SOLUTIONS REGARDING THE COVERAGE AND INTENSITY OF THE STORMS OVER
THE FOOTHILLS THIS AFTERNOON SO WILL NOT CHANGE ANY ANYTHING
REGARDING THE FLASH FLOOD WATCH AT THIS TIME. SINCE THE BURN AREAS
ALREADY GOT A GOOD DOSE OF RAINFALL YESTERDAY...THAT REASON ALONE
WILL JUSTIFY THE WATCH. SOME SOLUTIONS SUPPORT THE FLASH FLOOD
WATCH WHILE OTHERS ARE DRIER. HARD TO SAY AT THIS POINT...SO WILL
JUST HAVE TO MONITOR HOW THINGS DEVELOP.
&&
.AVIATION...SFC WINDS BECOMING NNELY AT THIS TIME SO TREND IN THE
WIND FCST STILL LOOKS ON TRACK. NO CHANGE REGARDING THE TIMING OF
TSTMS THIS AFTN AND EVENING AT THIS TIME. IF HEAVY RAIN DEVELOPS
WITH TSTMS THEN BRIEF MVFR CIGS/VSBYS WILL BE POSSIBLE.
&&
.PREV DISCUSSION... /ISSUED 317 AM MDT FRI JUL 19 2013/
SHORT TERM...WATER VAPOR LOOP SHOWS UPPER LEVEL MOISTURE PLUME
SHIFTING VERY SLOWLY SOUTHWARD ACROSS THE FORECAST AREA EARLY THIS
MORNING. MEANWHILE...LAST NIGHTS PERSISTENT CONVECTION HAS LEFT
BEHIND A MESOSCALE CONVECTIVE VORTEX...OR MCV...OVER NORTHERN
WELD COUNTY... CREEPING EASTWARD. MCVS ARE QUITE RARE AROUND
HERE...BUT CAN SERVE TO SPARK CONVECTION ON THE DOWNSHEAR...OR
SOUTH/SOUTHEAST SIDE IN THIS CASE. HARD TO SAY EXACTLY WHERE THIS
FEATURE WILL BE BY THE TIME WE REACH CONVECTIVE TEMPS...BUT SHOULD
BE SOMEWHERE IN NORTHEAST COLORADO.
OTHERWISE...AS THE WATER VAPOR PLUME CONTINUES TO SHIFT SOUTHWARD
THIS WILL BRING A BETTER CHANCE OF STORMS TO THE DENVER METRO
AREA/I-70 CORRIDOR/POINTS SOUTHWARD THIS AFTERNOON. WE COULD SEE A
FEW SHOWERS LINGER THIS MORNING AS WELL...BUT CONVECTIVE STORMS
WILL LIKELY INITIATE IN/NEAR THE FRONT RANGE AND DOWNSHEAR SIDE OF
THE MCV BY LATE MORNING/NOON HOUR AS CONVECTIVE TEMPS ARE
REACHED. POTENTIAL FOR HEAVY RAIN WILL BE THERE ESPECIALLY WITH
THE HIGHEST PRECIPITABLE WATER PLUME SHIFTING SOUTHWARD TODAY.
WHILE THE NORTHERN PORTIONS COULD SEE SOME DRYING AND EVEN
SUBSIDENCE ON THE UPSHEAR SIDE OF THE MCV...ENOUGH FACTORS
MENTIONED IN HYDROLOGY SECTION BELOW TO WARRANT A FLASH FLOOD
WATCH FOR THE FOOTHILLS WITH MAIN THREAT ONCE AGAIN FOR THE BURN
SCARS. COULD SEE RAINFALL RATES OF 1-1.5 INCHES IN 45 MINUTES
FROM THE STRONGEST STORMS. EXPECT THINGS TO WIND DOWN FAIRLY
QUICKLY THIS EVENING WITH SOME DRYING NOTED MOVING IN FROM THE
NORTH/NORTHWEST.
LONG TERM...A SLIGHT INCREASE IN NORTHWESTERLY FLOW ALOFT IS
EXPECTED SATURDAY ALONG WITH A THETA E RIDGE ACROSS EASTERN
COLORADO. CAPE VALUES OF BETWEEN 1000-1500 J/KG WILL BE FOUND OVER
FAR NORTHEASTERN COLORADO. THIS WILL ALL COMBINE TO BRING A SLIGHT
CHANCE OF SEVERE STRENGTH STORMS OVER THIS AREA.
ELSEWHERE...ENOUGH MOISTURE WILL BE AROUND TO ALLOW FOR ISOLATED
TO SCATTERED THUNDERSTORM ACTIVITY. MOISTURE WILL BE ON THE
DECREASE OVER TODAY HOWEVER...SO FLOODING CONCERNS ARE A LOT LESS.
TEMPERATURES WILL BE WARMING A FEW DEGREES AS THE UPPER HIGH OVER
NEVADA CIRCULATES WARMER AIR AROUND INTO THE STATE.
SUNDAY THROUGH THURSDAY WILL FEATURE THE UPPER HIGH OVER NEVADA TO
BEGIN TO MIGRATE BACK EAST. THIS WILL BRING AN OVERALL WARMING
PATTERN. SUNDAY AND MONDAY WILL BE MOSTLY DRY EXCEPT A FEW
POSSIBLE STORMS OVER THE HIGH COUNTRY. THEN A WEAK SHORTWAVE
COMING DOWN OUT OF THE NORTHERN ROCKIES MAY PUSH A COOL FRONT
DOWN THE LEE SIDE OF THE ROCKIES TO BRING A BRIEF RESPITE FROM THE
WARM AND DRY PATTERN. HOWEVER...MODELS DISAGREEING IF THIS FRONT
WILL MAKE IT INTO CO...FOR NOW WILL TREND THE FORECAST TO BRING IT
IN WITH COOLER TEMPS AND SLIGHT CHANCE OF STORMS FOR THE PLAINS
ON TUESDAY AND AREA WIDE WEDNESDAY.
FOR THURSDAY...IT LOOKS LIKE THE UPPER LOW WHICH RETROGRADED FROM
WEST VIRGINIA ALL THE WAY TO ITS CURRENT POSITION OVER SONORA,
MEXICO WILL CONTINUE ITS PATH WEST...THEN GET PULLED NORTH AROUND
THE UPPER HIGH. THEN ITS PROGGED TO MOVE EAST ONSHORE AND BRING
MORE MOISTURE OUR WAY FOR THURSDAY. HAVE POPS ACROSS THE FORECAST
AREA TO ACCOUNT FOR THIS.
AVIATION...STORM THREAT IS A LITTLE HIGHER TODAY GIVEN THE ABOVE
MENTIONED FACTORS SO WILL LIKELY NEED TEMPO TSRA AND GUSTY VRB
WINDS TO 35 KTS FOR A FEW HOURS THIS AFTERNOON. MAIN THREAT SHOULD
BE 20Z-01Z WITH STORMS SHIFTING SOUTH OF THE FRONT RANGE AIRPORTS
01Z-04Z. BRIEF IFR/MVFR CONDITIONS POSSIBLE WITH THE STRONGEST
STORMS. OTHERWISE VFR CONDITIONS WILL PREVAIL THROUGH TONIGHT.
HYDROLOGY...LOWER LIFTING CONDENSATION LEVELS AND RESULTANT
DEEPER WARM CLOUD DEPTH NEAR 1500 METERS MEANS MORE EFFICIENT
RAINERS POSSIBLE TODAY. AS A RESULT...HAVE OPTED FOR A FLASH FLOOD
WATCH FOR THE FRONT RANGE FOOTHILLS WITH MAIN THREAT OF FLASH
FLOODING ONCE AGAIN FOR THE BURN SCARS. COULD SEE RAINFALL RATES
OF 1-1.5 INCHES IN 45 MINUTES FROM THE STRONGEST STORMS. EXPECT
THINGS TO WIND DOWN BY 7-8 PM THIS EVENING WITH SOME DRYING NOTED
MOVING IN FROM THE NORTH/NORTHWEST. THERE IS A CHANCE OF
SUBSIDENCE AND DRYING MOVING IN A LITTLE EARLIER FOR THE NORTHERN
FRONT RANGE BURN SCARS INCLUDING HIGH PARK AND FOURMILE...BUT
STILL ENOUGH THREAT ESPECIALLY CONSIDERING RAINFALL YESTERDAY AND
ANTECEDENT CONDITIONS TO WARRANT A WATCH AT THIS TIME.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 8 PM MDT THIS EVENING FOR COZ035-036.
&&
$$
SHORT TERM...COOPER
LONG TERM....D-L
AVIATION...COOPER
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1121 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 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1120 MDT THU JUL 18 2013
VFR CONDITIONS EXPECTED AT TAF SITES THROUGH THE
REST OF TONIGHT WITH ISOLATED SHRA/TSRA CONTINUING TO DIMINISH
ACROSS THE HIGHER TERRAIN. ALS PICKED UP SOME RAIN THIS
EVENING...THOUGH THERE LOOKS TO BE ENOUGH MID AND HIGH LEVEL
CLOUDS TO KEEP FOG FROM FORMING OVERNIGHT. SHOWERS AND
THUNDERSTORMS WILL BE ON THE UPSWING EARLY FRIDAY MORNING AS A
WEAK DISTURBANCE EMBEDDED WITHIN THE MONSOON MOISTURE PLUME MOVES
SOUTH ACROSS THE STATE. COULD SEE SHOWERS AND THUNDERSTORMS
AFFECTING COS AND PUB BETWEEN 16Z-21Z AND THROUGH THE AFTERNOON
FOR ALS. MVFR AND BRIEF IFR CONDITIONS WILL BE POSSIBLE WITH
LOCALLY HEAVY RAINFALL. HAVE KEPT VCTS IN THROUGH THE LATE
AFTERNOON WITH CONVECTION LIKELY WINDING DOWN THROUGH THE EVENING.
$$
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AVIATION...MW
AREA FORECAST DISCUSSION
NWS MIAMI FL
1027 PM EDT SAT JUL 20 2013
.UPDATE...
ONLY A FEW CHANGES WERE NECESSARY THIS EVENING BASED ON THE LATEST
TRENDS AND OBSERVATIONS AROUND THE LOCAL AREA. OTHERWISE...THE
PREVIOUS FORECAST PACKAGE REMAINS ON TRACK. THE AFTERNOON/EARLY
EVENING CONVECTION THAT MOSTLY IMPACTED THE INTERIOR AREAS AROUND
THE LAKE REGION HAS DIMINISHED. THE LATEST HRRR RUN HAS LINED UP
WELL WITH THE CURRENT CONDITIONS AND GENERALLY INDICATES A QUIET
NIGHT WITH THE EXCEPTION OF SOME SHOWERS DEVELOPING OVER THE
ATLANTIC WATERS THROUGH THE OVERNIGHT HOURS. FOR SUNDAY...DRIER
AIR WILL BEGIN TO SPREAD NORTH INTO THE AREA AS THE RIDGE BEGINS
TO BUILD OVERHEAD AND THE WEAK TROUGH LIFTS AWAY FROM THE AREA.
HOWEVER...LINGERING MOISTURE OVER THE NORTHERN HALF OF THE
CWA...OR AROUND THE LAKE REGION...WITH PWAT VALUES AROUND 2"
COMBINED WITH SW LOW-LEVEL FLOW WILL BE ENOUGH TO THE KEEP THE
AFTERNOON/EVENING SHOWERS/TSTMS IN THE FORECAST.
&&
.PREV DISCUSSION... /ISSUED 723 PM EDT SAT JUL 20 2013/
AVIATION...
OUTFLOW FROM INTERIOR CONVECTION IS MEETING DECAYING SEA BREEZE
BOUNDARY OVER THE EASTERN METROPOLITAN AREAS THIS EVENING...THUS
VCSH/VCTS IN TAFS BROWARD AND PALM BEACH COUNTIES TERMINALS.
OUTFLOW BOUNDARY SHOULD BRING A BRIEF PERIOD OF WNW WINDS TO
MIAMI-DADE TERMINALS...SO HAVE INCLUDED A TEMPO GROUP NOTING THE
WIND SHIFT. OTHERWISE...LIGHT ESE WINDS WILL PREVAIL...AT SPEEDS
OF AROUND 5 KTS TONIGHT AND 10 KTS ON SUNDAY. HAVE REMOVED VCSH
BEYOND MIDNIGHT...AS POPS OVER THE TERMINALS ARE BELOW 30 PERCENT
THROUGH SUNDAY.
PREV DISCUSSION... /ISSUED 213 PM EDT SAT JUL 20 2013/
SHORT TERM (TONIGHT-MONDAY NIGHT)...
A STRONG MID LEVEL RIDGE OVER THE MID ATLANTIC STRETCHES WEST TO
ACROSS CENTRAL/SOUTH FLORIDA WITH MID LATITUDE TROUGHS MOVING ACROSS
THE NORTHERN TIER OF STATES AND CANADA. A TROPICAL WAVE IS CURRENTLY
MOVING THROUGH THE WESTERN CARIBBEAN SOUTHWEST OF JAMAICA AND THE
NORTHERN EXTENT OF THIS WAVE IS LOCATED FROM THE EASTERN FLORIDA
STRAITS AND INTO THE BAHAMAS. THIS HAS INCREASED CONVECTIVE ACTIVITY
IN THAT REGION WITH HIGHER PWAT VALUES MOVING INTO SOUTH FLORIDA
WHICH IN TURN IS HELPING TO ENHANCE CONVECTION. THE 12Z MFL SOUNDING
WAS QUITE IMPRESSIVE AS REGARDS TO THE AVAILABLE CAPE BUT SO FAR THE
STORMS HAVE BEEN SOMEWHAT SUPPRESSED DUE TO THE WEAK MID LEVEL LAPSE
RATES ASSOCIATED WITH THE RIDGE AXIS. THE LOW LEVELS WERE VERY
UNSTABLE HOWEVER AND THIS AIDED IN AN EARLY START TO THE CONVECTION
PROCESS WITH STORM MOTION TO THE NORTHWEST DUE TO THE LOW LEVEL
SOUTHEAST FLOW. THE FLOW BECOMES VERY WEAK TO LIGHT SOUTHWEST IN THE
MID LEVELS IN RESPONSE TO THE RIDGE SO AS THE STORMS CONTINUE TO
GROW, THE INTERIOR COULD GET QUITE ACTIVE LATER THIS AFTERNOON AS
THE STORM MOTION BECOMES LESS THAN 5 MPH.
THE WAVE WILL CONTINUE TO MOVE WEST OF THE AREA ON SUNDAY BUT AS
MOISTURE CONTINUES TO LINGER ACROSS THE REGION WITH A WEAK SURFACE
TROUGH BOUNDARY REMAINING IN PLACE, SCATTERED SHOWERS/THUNDERSTORMS
ARE EXPECTED AGAIN BY LATE SUNDAY MORNING INTO THE AFTERNOON. DUE TO
THE WAVE BEING FARTHER TO THE WEST, THE LOW LEVEL SOUTHEAST FLOW
WILL BECOME SHALLOWER SO STORM MOTION WILL GO EVEN LIGHTER AND SEA
BREEZE BOUNDARIES WILL LIKELY BE THE DOMINANT FOCUSING MECHANISM. AT
THE SAME TIME, A SURFACE RIDGE WILL BUILD BACK ACROSS SOUTH FLORIDA
BY SUNDAY AFTERNOON THROUGH MONDAY AND THIS COULD SUPPRESS
CONVECTIVE ACTIVITY EVEN FURTHER WITH SEA BREEZE BOUNDARIES AGAIN
BEING THE MAIN FOCUS FOR MONDAY AFTERNOON.
LONG TERM (TUESDAY-SATURDAY)...
THIS SAME TREND WILL LIKELY CONTINUE THROUGH THE MIDDLE OF THE WEEK
AS A DEEP LAYER RIDGE BECOMES FIRMLY ESTABLISHED AND FORECAST
SOUNDINGS SHOW STORM MOTION 2 MPH OR LESS. A STRONG MID LEVEL TROUGH
WILL BEGIN TO DEEPEN INTO THE EASTERN STATES BY THURSDAY INTO THE
END OF THE WEEK AND INTO THE FIRST PART OF NEXT WEEKEND FOR A SLOW
RETURN TO STORM MOTION STEERING STORMS BACK TOWARDS THE EAST COAST.
FORECAST SOUNDINGS HOWEVER ARE NOT SHOWING A STRONG MOTION SO THE
ENTIRE WEEK LOOKS AS IF VERY SLOW STORM MOTION WILL CONTINUE A
THREAT FOR LOCALLY HEAVY RAINS WHERE EVER THE CONVECTION CAN SET UP.
MARINE...
GENERAL EAST TO SOUTHEAST WIND IS EXPECTED THROUGH TUESDAY AT
SPEEDS OF LESS THAN 15 KNOTS OUTSIDE OF SCATTERED
SHOWERS/THUNDERSTORMS. THE WIND WILL BEGIN TO VEER TO A SOUTH OR
SOUTHWEST DIRECTION LATER IN THE WEEK AS THE SURFACE RIDGE SHIFTS
TO THE SOUTH.
FIRE WEATHER...
NO PROBLEMS WITH PLENTY OF TROPICAL MOISTURE IN PLACE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 76 89 76 88 / 20 20 20 30
FORT LAUDERDALE 78 89 79 89 / 20 20 20 30
MIAMI 77 90 77 88 / 20 20 20 20
NAPLES 76 91 75 89 / 10 20 10 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...85/AG
AVIATION/RADAR...23/SK
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
402 AM EDT Fri Jul 19 2013
.NEAR TERM [Today and Tonight]...
As has been advertised for the past couple days, we should be seeing
a deep plume of tropical moisture arrive this morning. GOES blended
precipitable water product shows the highest values lurking just
offshore in the northeast Gulf of Mexico - on the order of 2.2 to
2.4 inches. This is actually not entirely unreasonable, as the 00z
TBW sounding last evening sampled a 2.36" PWAT. The HRRR, other
convection-allowing models (CAM), and even the global models show
our PWATs increasing into this range later today. Forecast soundings
also show a very deep warm cloud layer and weak flow in the
mid-upper levels. Such environments can support very efficient rain
production due to warm-rain processes, as well as backbuilding and
quasi-stationary heavy rain bands.
The global models are not really projecting much QPF over the next
24 hours, and our current grids only call for about 1-2" of rain
through Saturday evening. However, CAM guidance and the HRRR do
indicate localized maxima as high as 6-8" through tonight. Given
that the environment can support very heavy rainfall, and the QPF
signatures on the CAM guidance, we have issued a Hydrologic Outlook
for all of our Florida zones. A Flash Flood Watch may become
necessary depending on how things evolve during the daytime hours.
For the forecast: PoPs were nudged up slightly again and "heavy
rainfall" wording was inserted near the Florida Big Bend where
models agree the best chances for heavy rain exist. Highs were kept
similar to the inherited forecast and the HRRR - with low 80s near
the Big Bend coast, to upper 80s in the northern third of our area.
PoPs were kept above MOS overnight with warm temperatures as we may
not see the usual diurnal cycle given the tropical air mass. In
fact, our local WRF-ARW shows a band of heavy rain persisting
through much of the night in parts of our Florida zones.
&&
.SHORT TERM [Saturday Through Sunday]...
It appears as though yet another wet and unsettled weekend is in
store for the Tri-State area once again, as the persistent Synoptic
scale pattern which keeps advecting deep layer tropical moisture
into the region from the Gulf of Mexico (shown well on the blended
TPW satellite product) will continue for much of the period. As
mentioned above, if this level of moisture (with PWATS again over
2") is productive enough to generate heavy rainfall, Flooding could
once again become a primary concern for parts of the CWA (as some
areas in the eastern FL panhandle have recently received between 15
to 20" of rain! On Sunday, there is "some" hope that both Sfc and
Upper level ridging will push far enough northward to at least bring
PoPs back closer to climo, before the seemingly never ending
troughing becomes re-established across the SE U.S by early mid
week. Even after 19 years of forecasting at WFO TAE (where the Sea
Breeze is typically the primary inducer of convection), the last 2
summers have been quite the aberration in my opinion. Therefore, it
remains to be seen if a somewhat more "typical" summertime pattern
can become established across the region before another summer has
gone by the wayside.
&&
.LONG TERM [Sunday Night through Wednesday]...
Deep layer ridging will dominate the first part of the extended
range forecast, with typical sea breeze patterns and rain chances
through Monday. Thereafter, a trough will nose into the Southeast,
nudging the mid/upper layer ridge out over our Gulf waters.
Additionally, some form of surface reflection will slip into the
Tri-State region and assist in the development of more widespread
shower and thunderstorm development through the remainder of the
period.
&&
.AVIATION [through 12 UTC Saturday]...
VFR conditions currently prevail at the TAF sites, and that is the
way that most of the available guidance portrays the next 24 hours.
However, with a very moist, tropical air mass moving into the area
and fairly widespread rain expected - that may be a little too
optimistic. We did insert some periods of MVFR this afternoon at all
of the terminals with +RA possible. This may not be reduced enough,
but confidence on location and timing of the heaviest rain was low.
Therefore, pilots and flight planners can expect increasing MVFR
over the region during the day, with IFR possible in and near the
heavier rain showers and storms.
&&
.MARINE...
Light to moderate southerly winds will continue to impact the
coastal waters, through Saturday, as an area of low pressure
gradually exits the region. By Sunday, and the remainder of the
period, high pressure at the surface should dominate, keeping winds
and seas on the light side, with possible enhancements nearshore
with the Sea Breeze, but this may not occur if conditions become and
remain too disturbed aloft.
&&
.FIRE WEATHER...
Red flag conditions are not expected for the next several days.
&&
.HYDROLOGY...
A plume of deep tropical moisture is shifting toward the northeast
gulf coast early this morning, and will overspread the interstate
10 corridor in Florida by midday. within this plume of tropical
moisture, bands of heavy rain or thunderstorms are expected to
develop and increase in coverage through the day. in environments
such as this, heavier showers and thunderstorms can produce a
considerable amount of rainfall in a short period of time.
Average rainfall totals through Saturday evening across the
Florida panhandle and big bend should be on the order of 1 to 2
inches. That amount of rainfall would generally be insufficient to
produce much flooding across the area. However, localized rain
totals could be quite a bit higher where heavier rain bands or
thunderstorms can persist for more than an hour. Isolated totals
in excess of 4 inches, perhaps as high as 6 to 8 inches, cannot
be ruled out. Rainfall such as that could contribute to localized
flooding, particularly in urban and low lying areas, and on
rivers that are already experiencing high flows such as the St.
Marks Aucilla rivers.
A Flash Flood Watch could become necessary later today if model
guidance becomes more supportive of localized very heavy rain
amounts.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 83 74 88 73 92 / 70 50 60 30 40
Panama City 84 77 86 76 88 / 60 50 60 30 40
Dothan 88 74 88 72 89 / 50 40 60 30 50
Albany 89 73 88 73 90 / 50 40 60 30 50
Valdosta 85 73 90 74 92 / 70 50 60 30 50
Cross City 83 74 87 72 89 / 70 60 60 30 40
Apalachicola 82 77 86 77 86 / 70 60 60 30 40
&&
.TAE WATCHES/WARNINGS/ADVISORIES,
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Lamers
SHORT TERM...Gould
LONG TERM...Harrigan/Navarro
AVIATION...Lamers
MARINE...Gould
FIRE WEATHER...Lamers
HYDROLOGY...Lamers
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
334 PM EDT FRI JUL 19 2013
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
CURRENT SATELLITE LOOP SHOWS CU FIELD CONTINUING TO DEVELOP ACROSS
THE REGION THIS AFTERNOON. SCATTERED SHOWERS ACROSS NORTH AND SOUTH
GA HAVE DEVELOPED OVER THE LAST FEW HOURS AND SHOULD CONTINUE
THROUGH TONIGHT. THE MODELS ARE IN GOOD AGREEMENT IN THE SHORT TERM
WITH THE GFS AND ECMWF SHOWING A NICE SLUG OF TROPICAL MOISTURE
MOVING NORTHWARD OUT OF THE GULF TONIGHT. THIS MOISTURE IS EXPECTED
TO MOVE SLOWLY NORTHWARD AND SHOULD BE ACROSS OUR AREA THOUGH THE
WEEKEND. THE MAIN UPPER LEVEL LOW OVER THE GULF WILL FINALLY OPEN
INTO A SHORT WAVE TROUGH BY SATURDAY AFTERNOON PUTTING GA IN GOOD
SOUTHWEST FLOW. THIS WILL ALSO HELP TO ENHANCE THE SHRA/TSRA
PROBABILITY ACROSS THE STATE. THIS INCREASED MOISTURE IS NOT
EXPECTED TO BRING RAIN ACROSS THE AREA FOR WEEKS ON END LIKE WE
EXPERIENCED IN MID JUNE THROUGH THE BEGINNING OF JULY. THE PATTERN
WE ARE IN IS A MORE SUMMER LIKE PATTERN WITH DIURNALLY DRIVEN
INSTABILITY AND CONVECTION SO ANYTHING THAT DOES DEVELOP THIS
AFTERNOON AND SATURDAY AFTERNOON SHOULD DIMINISH AFTER SUNSET.
01
.LONG TERM /SUNDAY THROUGH FRIDAY/...
MODELS ARE IN GOOD AGREEMENT WITH PEGGING BETTER PRECIP ACROSS
NORTH GEORGIA ON SUNDAY SO WENT AHEAD AND INTRODUCED LIKELY TO
THAT AREA. OTHERWISE ONLY MINOR TWEAKS TO THE EXTENDED AND THE
PREVIOUS DISCUSSION FOLLOWS.
11
LONG TERM /SATURDAY THROUGH THURSDAY/...
/ISSUED AT 349 AM EDT FRI JUL 19 2013/
MEDIUM RANGE MODELS START OUT QUITE SIMILAR TO BEGIN THE EXTENDED
FORECAST PERIOD WITH A BROAD WEAKNESS IN THE UPPER FLOW OVER THE
REGION THROUGH THE WEEKEND AS WEAK UPPER TROUGHING TAKES SHAPE ACROSS
THE EASTERN U.S. THROUGH EARLY NEXT WEEK. THERE IS SOME MODEL
DIVERGENCE IN THE EXACT PLACEMENT AND STRENGTH OF THE EASTERN U.S.
UPPER TROUGH BY THE LATTER HALF OF NEXT WEEK...BUT BOTH THE GFS AND
ECMWF MAINTAIN THIS FEATURE THROUGH THE PERIOD. SURFACE FEATURES SHOW
SIMILAR SLIGHT DEPARTURES BETWEEN THE MODELS...BUT THE GENERAL THEME
AMONG THE MEDIUM RANGE MODELS IS FOR GEORGIA TO BE ON THE NORTHWEST
SIDE OF THE WESTERN ATLANTIC RIDGE WITH PERSISTENT WEAK TROUGHING IN
THE LEE OF THE APPALACHIANS EXTENDING SOUTHWEST INTO THE FORECAST
AREA. THIS SHOULD PROVIDE AMPLE MOISTURE OVER THE REGION FOR AT LEAST
SCATTERED CONVECTION THROUGH THE PERIOD...WITH A NORMAL SUMMERTIME
DIURNAL BIAS. ANY WEAK RIPPLES MOVING THROUGH THE UPPER FLOW WILL
ENHANCE CONVECTIVE CHANCES...BUT TIMING OF ANY SUCH FEATURES ARE
PROBLEMATIC AT BEST IN THE EXTENDED FORECAST PERIOD AND WITH THE LACK
OF ANY CONSENSUS BETWEEN THE MODELS CONCERNING ANY LARGER...MORE
ORGANIZED WAVES I HAVE CHOSEN TO KEEP POPS BELOW LIKELY THROUGH THE
PERIOD.
20
&&
.AVIATION...
8Z UPDATE...
SATELLITE LOOP SHOWS CU FIELD DEVELOPING ACROSS THE REGION THIS
AFTERNOON WITH SOME ISOLATED SHOWERS NORTH AND SOUTH OF THE TAF
SITES. SO FAR THE PRECIP HAS STAYED AWAY FROM THE TAF SITES BUT
THE HRRR SHOWS A CLUSTER OF SHRA/TSRA DEVELOPING JUST WEST OF ATL
BY 00Z. WILL KEEP THE TEMPO GROUP IN FROM 21 TO 01 TO COVER THIS
AND WILL HAVE TO KEEP AN EYE ON THE SITUATION. WINDS ARE MAINLY
6KT OR LESS OUT OF THE SW BUT AM SEEING SOME SE WINDS AT TIMES.
CEILINGS AND VSBYS SHOULD STAY VFR THROUGH THE PERIOD EXCEPT IN
AND AROUND SHRA/TSRA DEVELOPMENT.
//ATL CONFIDENCE...18Z UPDATE...
CONFIDENCE MEDIUM TO HIGH ON ALL ELEMENTS
01
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 71 88 72 87 / 20 50 50 50
ATLANTA 72 87 73 85 / 20 60 60 50
BLAIRSVILLE 68 84 67 81 / 20 50 50 60
CARTERSVILLE 70 89 70 86 / 20 50 50 50
COLUMBUS 73 89 73 89 / 30 60 60 50
GAINESVILLE 72 87 72 84 / 20 50 50 50
MACON 72 89 72 89 / 30 60 60 50
ROME 70 89 70 87 / 20 50 50 50
PEACHTREE CITY 71 87 71 86 / 20 60 60 50
VIDALIA 72 89 73 89 / 40 60 60 50
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...01
LONG TERM....11
AVIATION...01
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
156 PM EDT FRI JUL 19 2013
.PREV DISCUSSION... /ISSUED 727 AM EDT FRI JUL 19 2013/
SHORT TERM /TODAY THROUGH TONIGHT/...
/ISSUED AT 349 AM EDT FRI JUL 19 2013/
FOR THIS MORNING...SCATTERED SHOWERS HAVE MOVED OFF THE ATLANTIC AND
INTO SOUTHEAST GA. SOME OF THESE WILL MOVE INTO THE SOUTHEAST CORNER
OF THE CWA EARLY THIS MORNING AND SPREAD WESTWARD ACROSS THE REST OF
CENTRAL GA THIS MORNING. DAYTIME HEATING WILL AID IN CONVECTION THIS
AFTERNOON WITH THE BEST RISK IN THE MOUNTAINS AND ALSO CENTRAL GA.
LATEST MODELS SHOW THE SURGE OF MOISTURE EXPECTED FOR TODAY IS
COMING IN MUCH SLOWER THAN PREVIOUS RUNS...BRINGING IT INTO THE CWA
SATURDAY AFTERNOON. THE H5 LOW WILL FINALLY OPEN INTO A SHORT WAVE
TROUGH BY SATURDAY AFTERNOON AND THIS WILL PUT THE CWA IN A
SOUTHWEST FLOW. BOTH GFS/NAM INDICATE A SIGNIFICANT SHORT WAVE
MOVING INTO THE CWA SATURDAY AFTERNOON AND THIS SHOULD BRING
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS.
17
LONG TERM /SATURDAY THROUGH THURSDAY/...
/ISSUED AT 349 AM EDT FRI JUL 19 2013/
MEDIUM RANGE MODELS START OUT QUITE SIMILAR TO BEGIN THE EXTENDED
FORECAST PERIOD WITH A BROAD WEAKNESS IN THE UPPER FLOW OVER THE
REGION THROUGH THE WEEKEND AS WEAK UPPER TROUGHING TAKES SHAPE ACROSS
THE EASTERN U.S. THROUGH EARLY NEXT WEEK. THERE IS SOME MODEL
DIVERGENCE IN THE EXACT PLACEMENT AND STRENGTH OF THE EASTERN U.S.
UPPER TROUGH BY THE LATTER HALF OF NEXT WEEK...BUT BOTH THE GFS AND
ECMWF MAINTAIN THIS FEATURE THROUGH THE PERIOD. SURFACE FEATURES SHOW
SIMILAR SLIGHT DEPARTURES BETWEEN THE MODELS...BUT THE GENERAL THEME
AMONG THE MEDIUM RANGE MODELS IS FOR GEORGIA TO BE ON THE NORTHWEST
SIDE OF THE WESTERN ATLANTIC RIDGE WITH PERSISTENT WEAK TROUGHING IN
THE LEE OF THE APPALACHIANS EXTENDING SOUTHWEST INTO THE FORECAST
AREA. THIS SHOULD PROVIDE AMPLE MOISTURE OVER THE REGION FOR AT LEAST
SCATTERED CONVECTION THROUGH THE PERIOD...WITH A NORMAL SUMMERTIME
DIURNAL BIAS. ANY WEAK RIPPLES MOVING THROUGH THE UPPER FLOW WILL
ENHANCE CONVECTIVE CHANCES...BUT TIMING OF ANY SUCH FEATURES ARE
PROBLEMATIC AT BEST IN THE EXTENDED FORECAST PERIOD AND WITH THE LACK
OF ANY CONSENSUS BETWEEN THE MODELS CONCERNING ANY LARGER...MORE
ORGANIZED WAVES I HAVE CHOSEN TO KEEP POPS BELOW LIKELY THROUGH THE
PERIOD.
20
&&
.AVIATION...
18Z UPDATE...
SATELLITE LOOP SHOWS CU FIELD DEVELOPING ACROSS THE REGION THIS
AFTERNOON WITH SOME ISOLATED SHOWERS NORTH AND SOUTH OF THE TAF
SITES. SO FAR THE PRECIP HAS STAYED AWAY FROM THE TAF SITES BUT
THE HRRR SHOWS A CLUSTER OF SHRA/TSRA DEVELOPING JUST WEST OF ATL
BY 00Z. WILL KEEP THE TEMPO GROUP IN FROM 21 TO 01 TO COVER THIS
AND WILL HAVE TO KEEP AN EYE ON THE SITUATION. WINDS ARE MAINLY
6KT OR LESS OUT OF THE SW BUT AM SEEING SOME SE WINDS AT TIMES.
CEILINGS AND VSBYS SHOULD STAY VFR THROUGH THE PERIOD EXCEPT IN AND
AROUND SHRA/TSRA DEVELOPMENT.
//ATL CONFIDENCE...18Z UPDATE...
CONFIDENCE MEDIUM TO HIGH ON ALL ELEMENTS
01
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 90 71 88 72 / 20 20 50 50
ATLANTA 90 72 87 73 / 20 20 60 60
BLAIRSVILLE 87 68 84 67 / 30 20 50 50
CARTERSVILLE 91 70 89 70 / 20 20 50 50
COLUMBUS 94 73 89 73 / 40 30 60 60
GAINESVILLE 88 72 87 72 / 20 20 50 50
MACON 92 72 89 72 / 40 30 60 60
ROME 91 70 89 70 / 20 20 50 50
PEACHTREE CITY 89 71 87 71 / 20 20 60 60
VIDALIA 91 72 89 73 / 50 40 60 60
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...01
LONG TERM....11
AVIATION...01
AREA FORECAST DISCUSSION
NWS LINCOLN IL
859 PM CDT SAT JUL 20 2013
.DISCUSSION...
ISSUED 858 PM CDT SAT JUL 20 2013
SOMEWHAT COMPLICATED SCENARIO FOR THE OVERNIGHT AS OPPOSED TO THE
LAST SEVERAL NIGHTS. CONVECTION ALONG THE I-64 CORRIDOR HAS BEEN
PERSISTENT THE LAST FEW HOURS. ALTHOUGH THE HEAVIEST RAIN IS NOW
WELL SOUTH OF OUR AREA...THE EXTREME SOUTHEAST CWA HAS SEEN LIGHT
TO MODERATE RAIN CONTINUING. THE FRONTAL BOUNDARY HAS BEGUN TO
RETROGRADE WESTWARD...WITH IT APPEARING FAIRLY NICELY ON RADAR
IMAGERY FROM JERSEYVILLE TO DECATUR TO JUST WEST OF CHAMPAIGN.
LATEST RAP AND HRRR GUIDANCE DOES NOT SHOW MUCH IN THE WAY OF
STEERING CURRENTS WHICH WOULD FULLY PUSH IT BACK SOUTHEAST OF THE
AREA...BUT THEY INDICATE THAT IT SHOULD NOT GET TOO MUCH FURTHER
NORTHWEST. WITH LIGHT WINDS...POOLING DEW POINTS NEAR 70 AND THE
MOISTURE FROM THE HEAVIER RAIN POCKETS FROM EARLIER TODAY... HAVE
SOME CONCERNS WITH FOG DEVELOPMENT ACROSS THE SOUTHEAST THIRD OF
THE CWA DESPITE THE AMOUNT OF CLOUDS. HAVE ADDED SOME PATCHY FOG
FOR THIS AREA OVERNIGHT. DID NOT REALLY CHANGE THE LOW
TEMPERATURES...BUT HAD TO MAKE SOME SIGNIFICANT ADJUSTMENTS TO THE
HOURLY TRENDS...ESPECIALLY IN THE SOUTHEAST DUE TO THE RAIN.
UPDATED GRIDS HAVE BEEN SENT. EARLIER ZONE ISSUANCE AT 7 PM
ALREADY TOOK INTO ACCOUNT MOST OF THE UPDATES...BUT WILL FRESHEN
THIS AS WELL TO ADD THE FOG MENTION.
GEELHART
&&
.AVIATION...
ISSUED 614 PM CDT SAT JUL 20 2013
COLD FRONT HAS PASSED THROUGH KDEC/KCMI OVER THE LAST HOUR OR SO.
STILL SEEING SOME EXTENSIVE CLOUD COVER THERE DUE TO CONVECTION
SOUTH OF THE FRONT IN SOUTHERN ILLINOIS...WITH CEILINGS BREAKING
UP OVER THE NEXT COUPLE HOURS. OVERNIGHT CONCERN REMAINS WITH
POTENTIAL FOR SOME MVFR CONDITIONS DUE TO LIGHT FOG...WITH THE
WINDS REMAINING LIGHT OVERNIGHT AND TEMPERATURE/DEW POINT SPREADS
FAIRLY MINIMAL DESPITE SOMEWHAT DRIER AIR FILTERING IN. LATER ON
SUNDAY AFTERNOON...POTENTIAL FOR SCATTERED THUNDERSTORMS INCREASES
FROM THE WEST...AS AN UPPER DISTURBANCE APPROACHES THE MISSISSIPPI
VALLEY. HAVE INTRODUCED SOME VCTS AT KPIA/KSPI FOR THE LAST FEW
HOURS OF THE FORECAST...BUT HELD OFF FURTHER EAST AS IT CURRENTLY
APPEARS TO BE MORE OF AN EVENING THREAT IN THAT AREA.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 248 PM CDT SAT JUL 20 2013
MODELS LOOK IN VERY GOOD AGREEMENT IN THE SHORT TERM PERIOD...AS
MAIN CONCERN IS PCPN CHANCES AND TEMPS. EXTENDED MODELS HAVE SOME
DIFFERENCES BUT THEY ARE MINOR AND DO NOT CHANGE THE OVERALL
FORECAST THAT MUCH...EXCEPT TO BRING IN SOME DRIER PERIODS DURING
MIDDLE OF THE WEEK. SO OVERALL CONFIDENCE IN FORECAST IS GOOD.
SHORT TERM...TONIGHT THROUGH TUESDAY
FRONT HAS BEEN MOVING SOUTH THROUGH THE AREA TODAY AND WILL
CONTINUE TO MOVE SOUTH LATE THIS AFTERNOON AND EVENING.
THUNDERSTORMS HAVE DEVELOPED ALONG THE FRONT AS IT HAS INTERACTED
WITH JUICY AIR WITH LOWER TO MIDDLE 70S DEWPOINTS. WITH
THUNDERSTORMS THAT HAVE NOW DEVELOPED JUST NORTH OF I-70...WILL
HAVE A LATE AFTERNOON PERIOD IN THE WORDED FORECAST ONCE IT IS
ISSUED. OTHERWISE...TONIGHT THUNDERSTORMS WILL JUST BE IN THE
SOUTHEAST JUST FOR THIS EVENING AND THEN DRY FOR AFTER MIDNIGHT.
AS CAN BE SEEN ON VISIBLE SATELLITE AND RADAR IMAGES OUT
WEST...THE FRONT EXTENDS BACK TO THE NORTHWEST WITH MORE SHOWERS
AND THUNDERSTORMS. THIS FRONT WILL BE THE FOCUS FOR MORE
DEVELOPMENT TOMORROW THAT WILL ADVECT TOWARD WESTERN ILLINOIS
TOMORROW MORNING AND CENTRAL ILLINOIS TOMORROW AFTERNOON.
THUNDERSTORM CHANCES WILL CONTINUE INTO TOMORROW NIGHT AS A SHORT
WAVE MOVES ACROSS THE AREA AS WELL. POPS WILL BE HIGHEST TOMORROW
NIGHT DUE TO THIS SHORT WAVE AS WELL. PCPN CHANCES WILL CONTINUE
INTO MONDAY...THOUGH LOWER...AS THE SHORT WAVE MOVES EAST OF THE
AREA.
A SECOND WAVE OR MCS WILL THEN DEVELOP OUT WEST AND MOVE INTO THE
AREA FOR MON NIGHT INTO TUESDAY. THIS WILL BRING CONTINUED
THUNDERSTORM CHANCES FROM WEST TO EAST. CHANCES THEN DIMINISH FROM
THE WEST TUE INTO TUE NIGHT.
TEMP WILL REMAIN WARM AND WITH HIGH DEWPOINTS...MUGGY CONDITIONS
WILL CONTINUE. AFTERNOON HIGHS ARE EXPECTED TO STILL REACH INTO
THE MIDDLE TO UPPER 80S WITH NEAR 90 DEGREES IN THE SOUTHEAST ON
MONDAY.
LONG TERM...TUESDAY NIGHT THROUGH SATURDAY
AS THE SECOND WAVE MOVES THROUGH THE AREA...THUNDERSTORMS WILL
PROBABLY STILL BE POSSIBLE IN THE SOUTHEAST SECTIONS FOR TUE
NIGHT...SO WILL KEEP CHC POPS THERE. THIS SECOND WAVE SHOULD BE
STRONG ENOUGH TO PUSH THE FRONT WELL SOUTH AND BRING A PERIOD OF
DRY WEATHER TO THE AREA. UPPER LEVEL FLOW WILL ALSO BE OUT OF THE
NORTHWEST...SO CONDITIONS SHOULD BE A TAD COOLER DURING THE DAY.
CURRENT EXTENDED MODELS INDICATE THAT DRY WEATHER WILL PREVAIL
THROUGH THURSDAY NIGHT AS MODELS DO NOT SHOW ANY SHORT WAVES
MOVING THROUGH THE AREA DURING THAT PERIOD. HOWEVER...MODELS DO
NOT DO WELL WITH SMALL WEAK FEATURES IN NORTHWEST FLOW SO DON`T BE
SURPRISED IF THIS CHANGES OVER THE NEXT COUPLE OF DAYS. THE NEXT
REAL CHANCE OF SHOWERS AND THUNDERSTORMS APPEARS NOT TO BE UNTIL
FRIDAY THROUGH SATURDAY AS A MID LEVEL TROUGH MOVES TOWARD THE
AREA. CURRENTLY THIS SYSTEM LOOKS TO REMAIN WEST OF THE AREA BUT
STILL BRING PCPN TO ALL OF CENTRAL AND SOUTHEAST ILLINOIS FOR END
OF THE WEEK.
TEMPS WILL REMAIN AROUND NORMAL BUT THEN BECOME COOLER...
POSSIBLY...AT THE END OF THE WEEK AND BEGINNING OF THE WEEKEND.
AUTEN
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
552 PM CDT FRI JUL 19 2013
.MESOSCALE DISCUSSION...540 PM...
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 22Z...
* ISOLD-SCT SHRA/TSRA STILL POSSIBLE BUT HAVE SLOWED TIMING TO
01-04Z.
* GUSTY SW WINDS BETWEEN 20-25KT WITH A FEW GUSTS TO 30 KT THRU
EARLY THIS EVE.
* WIND DIR SHIFTING FROM WEST TO NORTH LATE THIS EVENING. THEN
WINDS STEADILY TURN NORTHEAST BY DAYBREAK SAT. SPEEDS TONIGHT
THRU MIDDAY SAT WILL GENERALLY BE 7-10KT.
MDB
//DISCUSSION...UPDATED 22Z...
CONTINUING TO MONITOR TSRA POTENTIAL INTO THE EVENING. COLD
FRONTAL BOUNDARY FROM ROUGHLY GRB TO DLL TO PDC AT 22Z.
SATELLITE SHOWS SEVERAL NARROW BANDS OF FAIRLY WELL DEVELOPED CU
WITH THE CU RIGHT ALONG THE FRONT STARTING TO CATCH UP TO THE BAND
FURTHER AHEAD OF IT. DEVELOPMENT IS STARTING TO OCCUR AND COVERAGE
MAY INCREASE TO A DEGREE OVER THE NEXT HOUR AS THE TWO BANDS OF CU
MEET. ANY ACTIVITY THAT DOES DEVELOP WILL STILL BE SEVERAL HOURS
OUT FROM THE TERMINALS AND HAVE FURTHER SLOWED MENTION IN THE
TAFS...WITH ADDITIONAL SLOWING POSSIBLE. COVERAGE IS STILL IN
QUESTION...ESPECIALLY WITH EARLIEST ARRIVAL NEAR THE TERMINALS
COMING CLOSER TO SUNSET SO ACTIVITY COULD BE ON A DOWNWARD TREND.
MDB
FROM 18Z...
ATMOSPHERE OVER NORTHERN IL/NORTHWEST IN BEGINNING TO BECOME
UNSTABLE AND PRIMED FOR ISOLATED SHOWERS AND THUNDERSTORMS TO
DEVELOP. FORECAST GUIDANCE CONTINUES TO FAVOR STEADILY INCREASED
COVERAGE/INTENSITY OF THUNDERSTORMS BY 20-21Z. CUMULUS CLOUDS WILL
THICKEN AND BUILD...AS THE CONVECTIVE POTENTIAL INCREASES. ALL OF
THIS ACTIVITY WILL DEVELOP AHEAD OF THE FRONTAL BOUNDARY...WITH
BREEZY CONDITIONS FROM THE SOUTHWEST. WINDS WILL GENERALLY BE THRU
FRONTAL PASSAGE AND WITH PRECIP ARND 20-25KT. THEN BY 00-01Z TSRA
COVERAGE WILL BEGIN TO DIMINISH AND SHIFT TO THE SOUTHEAST OF TAF
SITES. EXPECT BY 02Z TSRA TO HAVE COME TO AN END WITH WINDS
TURNING NORTH/NORTHEAST OVERNIGHT. THE GRADIENT BRIEFLY DIMINISHES
LATE TONIGHT...WITH WINDS POSSIBLY COMING DOWN TO LESS THAN 7KT.
SKIES WILL BECOME PARTLY CLOUDY WITH JUST A CIRRUS SHIELD
OVERNIGHT. JUST AFT DAYBREAK SAT WIND SPEEDS WILL INCREASE TO
12-15KT WITH MOSTLY CLEAR SKIES...THEN EXPECT DIURNAL CUMULUS
CLOUDS TO DEVELOP WITH BASES ARND 4KFT AGL...THIS SHUD HELP TO
TRIM WINDS BACK TO ARND 10KT.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* MEDIUM-HIGH CONFIDENCE IN TIMING OF TSRA POTENTIAL...MEDIUM
CONFIDENCE IN OCCURRENCE.
* HIGH CONFIDENCE IN WIND DIR/SPEED/GUSTS.
* HIGH CONFIDENCE IN WINDS TURNING NORTHEAST BY DAYBREAK SAT.
MDB
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...VFR. WX NIL.
SUNDAY...CHANCE OF TSRA AFTERNOON THROUGH OVERNIGHT.
MONDAY THROUGH WEDNESDAY...PERIODIC CHANCES TSRA.
THURSDAY...VFR. WX NIL.
KREIN
&&
.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 CHICAGO/ROMEOVILLE IL
510 PM CDT FRI JUL 19 2013
.MESOSCALE DISCUSSION...
CONTINUING TO MONITOR CONVECTIVE CHANCES THIS AFTERNOON INTO EARLY
EVENING WITH TRENDS SLOW TO GO THUS FAR AND CONTINUING TO APPEAR
THAT ANY SEVERE THREAT WOULD BE ISOLATED IN COVERAGE.
AS THE UPPER TROUGH CONTINUES TO DIG INTO THE FAR NORTHERN GREAT
LAKES THIS AFTERNOON...A NARROW PLUME OF DEEPER MOISTURE IN
ADVANCE AS SEEN ON WATER VAPOR HAS MOVED EAST INTO NORTHERN IL.
THERE HAS BEEN ACCAS AND AGITATED CU WITHIN THIS STREAM...ALONG
WITH SPORADIC ISOLATED SHOWERS ACROSS SOUTHERN WI AND NOW INTO
NORTHERN BOONE COUNTY IL. SUBTLE PRE-FRONTAL SURFACE CONVERGENCE
IS NOTED IN OBSERVATIONS UNDER THIS...BUT IT HAS BECOME
PROGRESSIVELY LESS CONVERGENT AS THE BOUNDARY LAYER HAS BECOME
WELL-MIXED. GIVEN THAT AN NO NOTICEABLE TRENDS ON SATELLITE OR
RADAR DO NOT FORESEE ANY WIDESPREAD CONVECTIVE GROWTH ON
THIS...ALTHOUGH ISOLATED TO SCATTERED STORMS COULD DEVELOP OR
FESTER...PROBABLY MOST FAVORED ACROSS FAR NORTHEAST IL.
FURTHER TO THE SOUTH A REMNANT ELEVATED OUTFLOW AS SEEN EARLIER
ON SATELLITE AND RADAR HAS STALLED ACROSS FAR NORTHERN IN
SOUTHWEST OVER KANKAKEE AND PONTIAC. THIS HAS TRIGGERED SOME CU
WITH BETTER VERTICAL GROWTH ALONG WITH SHOWERS NOW BEING SEEN
ALONG THE IN/MI BORDER WHERE CONVERGENCE APPEARS MORE DEFINED ON
STREAMLINE ANALYSIS. AN AREA OF 73-75 DEW POINTS ACROSS EAST
CENTRAL IL IS FEEDING INTO THIS AREA LEADING TO MLCAPES OF
3000-3500 J/KG. SIMILAR HERE...ISOLATED TO SCATTERED STORM
DEVELOPMENT COULD BE SEEN...WITH SLOW MOVING CELLS IF ANYTHING CAN
DEVELOP AS THE ACTIVITY IS FURTHER REMOVED FROM THE BETTER
STEERING FLOW TO THE NORTH.
OVERALL IT IS TRENDING THAT STORM CHANCES MAY BE BEST IN THE
FORECAST AREA JUST AHEAD OF THE COOL FRONT WHICH AS OF 230 PM IS
DRAPED FROM NORTHERN LAKE MI TO JUST SOUTH OF LA CROSSE WI. EVEN
THEN THE COVERAGE COULD BE LIMITED. TOWERING CU HAS BEEN SEEN
ALONG THIS AND THIS MAY FURTHER GROW AS THE FRONT UNDERCUTS THE
AFOREMENTIONED DEEPER MOISTURE ALOFT BY LATE THIS AFTERNOON.
SUBTLE SHORT WAVE ENERGY TRACKING EAST ACROSS NORTHERN IA COULD
INTERACT WITH THIS TO HELP SPRING ACTIVITY...BUT IT MAY STRUGGLE
LASTING DEEP INTO THE EVE AT LEAST WITH STRONG POTENTIAL GIVEN THE
DIURNAL HEATING OF THE DAY HAVING WANED. CONVECTIVE ALLOWING
GUIDANCE HAS QUITE A BIT OF RANGE IN SOLUTIONS...WHICH DOES NOT
HELP TO BOLSTER CONFIDENCE ANY.
LAPS AND RAP ANALYSIS AND SOUNDINGS INDICATE LARGE VALUES OF DCAPE
/1100+ J/KG/ WHICH COMBINED WITH PRECIPITATION LOADING CONCERNS
COULD FAVOR ISOLATED WET MICROBURSTS IN ANY STORMS...WHICH REMAINS
THE PRIMARY CONCERN. DEEP LAYER SHEAR IS SLOWLY INCREASING JUST
NOW APPROACHING 30 KT NEAR THE IL/WI BORDER...BUT IN GENERAL
REMAINS WEAK ELSEWHERE. OBVIOUSLY THE HIGH PWATS CONTINUE TO
SUPPORT HEAVY RAIN IN ANY STORM.
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 22Z...
* ISOLD-SCT SHRA/TSRA STILL POSSIBLE BUT HAVE SLOWED TIMING TO
01-04Z.
* GUSTY SW WINDS BETWEEN 20-25KT WITH A FEW GUSTS TO 30 KT THRU
EARLY THIS EVE.
* WIND DIR SHIFTING FROM WEST TO NORTH LATE THIS EVENING. THEN
WINDS STEADILY TURN NORTHEAST BY DAYBREAK SAT. SPEEDS TONIGHT
THRU MIDDAY SAT WILL GENERALLY BE 7-10KT.
MDB
//DISCUSSION...UPDATED 22Z...
CONTINUING TO MONITOR TSRA POTENTIAL INTO THE EVENING. COLD
FRONTAL BOUNDARY FROM ROUGHLY GRB TO DLL TO PDC AT 22Z.
SATELLITE SHOWS SEVERAL NARROW BANDS OF FAIRLY WELL DEVELOPED CU
WITH THE CU RIGHT ALONG THE FRONT STARTING TO CATCH UP TO THE BAND
FURTHER AHEAD OF IT. DEVELOPMENT IS STARTING TO OCCUR AND COVERAGE
MAY INCREASE TO A DEGREE OVER THE NEXT HOUR AS THE TWO BANDS OF CU
MEET. ANY ACTIVITY THAT DOES DEVELOP WILL STILL BE SEVERAL HOURS
OUT FROM THE TERMINALS AND HAVE FURTHER SLOWED MENTION IN THE
TAFS...WITH ADDITIONAL SLOWING POSSIBLE. COVERAGE IS STILL IN
QUESTION...ESPECIALLY WITH EARLIEST ARRIVAL NEAR THE TERMINALS
COMING CLOSER TO SUNSET SO ACTIVITY COULD BE ON A DOWNWARD TREND.
MDB
FROM 18Z...
ATMOSPHERE OVER NORTHERN IL/NORTHWEST IN BEGINNING TO BECOME
UNSTABLE AND PRIMED FOR ISOLATED SHOWERS AND THUNDERSTORMS TO
DEVELOP. FORECAST GUIDANCE CONTINUES TO FAVOR STEADILY INCREASED
COVERAGE/INTENSITY OF THUNDERSTORMS BY 20-21Z. CUMULUS CLOUDS WILL
THICKEN AND BUILD...AS THE CONVECTIVE POTENTIAL INCREASES. ALL OF
THIS ACTIVITY WILL DEVELOP AHEAD OF THE FRONTAL BOUNDARY...WITH
BREEZY CONDITIONS FROM THE SOUTHWEST. WINDS WILL GENERALLY BE THRU
FRONTAL PASSAGE AND WITH PRECIP ARND 20-25KT. THEN BY 00-01Z TSRA
COVERAGE WILL BEGIN TO DIMINISH AND SHIFT TO THE SOUTHEAST OF TAF
SITES. EXPECT BY 02Z TSRA TO HAVE COME TO AN END WITH WINDS
TURNING NORTH/NORTHEAST OVERNIGHT. THE GRADIENT BRIEFLY DIMINISHES
LATE TONIGHT...WITH WINDS POSSIBLY COMING DOWN TO LESS THAN 7KT.
SKIES WILL BECOME PARTLY CLOUDY WITH JUST A CIRRUS SHIELD
OVERNIGHT. JUST AFT DAYBREAK SAT WIND SPEEDS WILL INCREASE TO
12-15KT WITH MOSTLY CLEAR SKIES...THEN EXPECT DIURNAL CUMULUS
CLOUDS TO DEVELOP WITH BASES ARND 4KFT AGL...THIS SHUD HELP TO
TRIM WINDS BACK TO ARND 10KT.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* MEDIUM-HIGH CONFIDENCE IN TIMING OF TSRA POTENTIAL...MEDIUM
CONFIDENCE IN OCCURRENCE.
* HIGH CONFIDENCE IN WIND DIR/SPEED/GUSTS.
* HIGH CONFIDENCE IN WINDS TURNING NORTHEAST BY DAYBREAK SAT.
MDB
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...VFR. WX NIL.
SUNDAY...CHANCE OF TSRA AFTERNOON THROUGH OVERNIGHT.
MONDAY THROUGH WEDNESDAY...PERIODIC CHANCES TSRA.
THURSDAY...VFR. WX NIL.
KREIN
&&
.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.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
329 PM CDT FRI JUL 19 2013
.MESOSCALE DISCUSSION...239 PM CDT
CONTINUING TO MONITOR CONVECTIVE CHANCES THIS AFTERNOON INTO EARLY
EVENING WITH TRENDS SLOW TO GO THUS FAR AND CONTINUING TO APPEAR
THAT ANY SEVERE THREAT WOULD BE ISOLATED IN COVERAGE.
AS THE UPPER TROUGH CONTINUES TO DIG INTO THE FAR NORTHERN GREAT
LAKES THIS AFTERNOON...A NARROW PLUME OF DEEPER MOISTURE IN
ADVANCE AS SEEN ON WATER VAPOR HAS MOVED EAST INTO NORTHERN IL.
THERE HAS BEEN ACCAS AND AGITATED CU WITHIN THIS STREAM...ALONG
WITH SPORADIC ISOLATED SHOWERS ACROSS SOUTHERN WI AND NOW INTO
NORTHERN BOONE COUNTY IL. SUBTLE PRE-FRONTAL SURFACE CONVERGENCE
IS NOTED IN OBSERVATIONS UNDER THIS...BUT IT HAS BECOME
PROGRESSIVELY LESS CONVERGENT AS THE BOUNDARY LAYER HAS BECOME
WELL-MIXED. GIVEN THAT AN NO NOTICEABLE TRENDS ON SATELLITE OR
RADAR DO NOT FORESEE ANY WIDESPREAD CONVECTIVE GROWTH ON
THIS...ALTHOUGH ISOLATED TO SCATTERED STORMS COULD DEVELOP OR
FESTER...PROBABLY MOST FAVORED ACROSS FAR NORTHEAST IL.
FURTHER TO THE SOUTH A REMNANT ELEVATED OUTFLOW AS SEEN EARLIER
ON SATELLITE AND RADAR HAS STALLED ACROSS FAR NORTHERN IN
SOUTHWEST OVER KANKAKEE AND PONTIAC. THIS HAS TRIGGERED SOME CU
WITH BETTER VERTICAL GROWTH ALONG WITH SHOWERS NOW BEING SEEN
ALONG THE IN/MI BORDER WHERE CONVERGENCE APPEARS MORE DEFINED ON
STREAMLINE ANALYSIS. AN AREA OF 73-75 DEW POINTS ACROSS EAST
CENTRAL IL IS FEEDING INTO THIS AREA LEADING TO MLCAPES OF
3000-3500 J/KG. SIMILAR HERE...ISOLATED TO SCATTERED STORM
DEVELOPMENT COULD BE SEEN...WITH SLOW MOVING CELLS IF ANYTHING CAN
DEVELOP AS THE ACTIVITY IS FURTHER REMOVED FROM THE BETTER
STEERING FLOW TO THE NORTH.
OVERALL IT IS TRENDING THAT STORM CHANCES MAY BE BEST IN THE
FORECAST AREA JUST AHEAD OF THE COOL FRONT WHICH AS OF 230 PM IS
DRAPED FROM NORTHERN LAKE MI TO JUST SOUTH OF LA CROSSE WI. EVEN
THEN THE COVERAGE COULD BE LIMITED. TOWERING CU HAS BEEN SEEN
ALONG THIS AND THIS MAY FURTHER GROW AS THE FRONT UNDERCUTS THE
AFOREMENTIONED DEEPER MOISTURE ALOFT BY LATE THIS AFTERNOON.
SUBTLE SHORT WAVE ENERGY TRACKING EAST ACROSS NORTHERN IA COULD
INTERACT WITH THIS TO HELP SPRING ACTIVITY...BUT IT MAY STRUGGLE
LASTING DEEP INTO THE EVE AT LEAST WITH STRONG POTENTIAL GIVEN THE
DIURNAL HEATING OF THE DAY HAVING WANED. CONVECTIVE ALLOWING
GUIDANCE HAS QUITE A BIT OF RANGE IN SOLUTIONS...WHICH DOES NOT
HELP TO BOLSTER CONFIDENCE ANY.
LAPS AND RAP ANALYSIS AND SOUNDINGS INDICATE LARGE VALUES OF DCAPE
/1100+ J/KG/ WHICH COMBINED WITH PRECIPITATION LOADING CONCERNS
COULD FAVOR ISOLATED WET MICROBURSTS IN ANY STORMS...WHICH REMAINS
THE PRIMARY CONCERN. DEEP LAYER SHEAR IS SLOWLY INCREASING JUST
NOW APPROACHING 30 KT NEAR THE IL/WI BORDER...BUT IN GENERAL
REMAINS WEAK ELSEWHERE. OBVIOUSLY THE HIGH PWATS CONTINUE TO
SUPPORT HEAVY RAIN IN ANY STORM.
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 20Z...
* GUSTY SW WINDS BETWEEN 20-25KT WITH A FEW GUSTS TO 30 KT THRU
EARLY THIS EVE.
* ISO SHRA/TSRA DEVELOPING...BEST TIMING FOR STRONGER TSRA WOULD
BE AFT 21Z THRU 01Z.
* WIND DIR SHIFTING FROM WEST TO NORTH THIS EVENING. THEN WINDS
STEADILY TURN NORTHEAST BY DAYBREAK SAT. SPEEDS TONIGHT THRU
MIDDAY SAT WILL GENERALLY BE 7-10KT.
BEACHLER
//DISCUSSION...UPDATED 18Z...
ATMOSPHERE OVER NORTHERN IL/NORTHWEST IN BEGINNING TO BECOME
UNSTBALE AND PRIMED FOR ISOLATED SHOWERS AND THUNDERSTORMS TO
DEVELOP. FORECAST GUIDANCE CONTINUES TO FAVOR STEADILY INCREASED
COVERAGE/INTENSITY OF THUNDERSTORMS BY 20-21Z. CUMULUS CLOUDS WILL
THICKEN AND BUILD...AS THE CONVECTIVE POTENTIAL INCREASES. ALL OF
THIS ACTIVITY WILL DEVELOP AHEAD OF THE FRONTAL BOUNDARY...WITH
BREEZY CONDITIONS FROM THE SOUTHWEST. WINDS WILL GENERALLY BE THRU
FRONTAL PASSAGE AND WITH PRECIP ARND 20-25KT. THEN BY 00-01Z TSRA
COVERAGE WILL BEGIN TO DIMINISH AND SHIFT TO THE SOUTHEAST OF TAF
SITES. EXPECT BY 02Z TSRA TO HAVE COME TO AN END WITH WINDS
TURNING NORTH/NORTHEAST OVERNIGHT. THE GRADIENT BRIEFLY DIMINISHES
LATE TONIGHT...WITH WINDS POSSIBLY COMING DOWN TO LESS THAN 7KT.
SKIES WILL BECOME PARTLY CLOUDY WITH JUST A CIRRUS SHIELD
OVERNIGHT. JUST AFT DAYBREAK SAT WIND SPEEDS WILL INCREASE TO
12-15KT WITH MOSTLY CLEAR SKIES...THEN EXPECT DIURNAL CUMULUS
CLOUDS TO DEVELOP WITH BASES ARND 4KFT AGL...THIS SHUD HELP TO
TRIM WINDS BACK TO ARND 10KT.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM/HIGH CONFIDENCE IN SCT TSRA THIS AFTERNOON THRU EARLY EVENING.
* MEDIUM CONFIDENCE IN TIMING OF ARRIVAL/ENDING AT ORD/MDW.
* HIGH CONFIDENCE IN WIND DIR/SPEED/GUSTS.
* HIGH CONFIDENCE IN WINDS TURNING NORTHEAST BY DAYBREAK SAT.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...VFR. WX NIL.
SUNDAY...CHANCE OF TSRA AFTERNOON THROUGH OVERNIGHT.
MONDAY THROUGH WEDNESDAY...PERIODIC CHANCES TSRA.
THURSDAY...VFR. WX NIL.
KREIN
&&
.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.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
317 PM CDT FRI JUL 19 2013
.MESOSCALE DISCUSSION...
239 PM CDT
CONTINUING TO MONITOR CONVECTIVE CHANCES THIS AFTERNOON INTO EARLY
EVENING WITH TRENDS SLOW TO GO THUS FAR AND CONTINUING TO APPEAR
THAT ANY SEVERE THREAT WOULD BE ISOLATED IN COVERAGE.
AS THE UPPER TROUGH CONTINUES TO DIG INTO THE FAR NORTHERN GREAT
LAKES THIS AFTERNOON...A NARROW PLUME OF DEEPER MOISTURE IN
ADVANCE AS SEEN ON WATER VAPOR HAS MOVED EAST INTO NORTHERN IL.
THERE HAS BEEN ACCAS AND AGITATED CU WITHIN THIS STREAM...ALONG
WITH SPORADIC ISOLATED SHOWERS ACROSS SOUTHERN WI AND NOW INTO
NORTHERN BOONE COUNTY IL. SUBTLE PRE-FRONTAL SURFACE CONVERGENCE
IS NOTED IN OBSERVATIONS UNDER THIS...BUT IT HAS BECOME
PROGRESSIVELY LESS CONVERGENT AS THE BOUNDARY LAYER HAS BECOME
WELL-MIXED. GIVEN THAT AN NO NOTICEABLE TRENDS ON SATELLITE OR
RADAR DO NOT FORESEE ANY WIDESPREAD CONVECTIVE GROWTH ON
THIS...ALTHOUGH ISOLATED TO SCATTERED STORMS COULD DEVELOP OR
FESTER...PROBABLY MOST FAVORED ACROSS FAR NORTHEAST IL.
FURTHER TO THE SOUTH A REMNANT ELEVATED OUTFLOW AS SEEN EARLIER
ON SATELLITE AND RADAR HAS STALLED ACROSS FAR NORTHERN IN
SOUTHWEST OVER KANKAKEE AND PONTIAC. THIS HAS TRIGGERED SOME CU
WITH BETTER VERTICAL GROWTH ALONG WITH SHOWERS NOW BEING SEEN
ALONG THE IN/MI BORDER WHERE CONVERGENCE APPEARS MORE DEFINED ON
STREAMLINE ANALYSIS. AN AREA OF 73-75 DEW POINTS ACROSS EAST
CENTRAL IL IS FEEDING INTO THIS AREA LEADING TO MLCAPES OF
3000-3500 J/KG. SIMILAR HERE...ISOLATED TO SCATTERED STORM
DEVELOPMENT COULD BE SEEN...WITH SLOW MOVING CELLS IF ANYTHING CAN
DEVELOP AS THE ACTIVITY IS FURTHER REMOVED FROM THE BETTER
STEERING FLOW TO THE NORTH.
OVERALL IT IS TRENDING THAT STORM CHANCES MAY BE BEST IN THE
FORECAST AREA JUST AHEAD OF THE COOL FRONT WHICH AS OF 230 PM IS
DRAPED FROM NORTHERN LAKE MI TO JUST SOUTH OF LA CROSSE WI. EVEN
THEN THE COVERAGE COULD BE LIMITED. TOWERING CU HAS BEEN SEEN
ALONG THIS AND THIS MAY FURTHER GROW AS THE FRONT UNDERCUTS THE
AFOREMENTIONED DEEPER MOISTURE ALOFT BY LATE THIS AFTERNOON.
SUBTLE SHORT WAVE ENERGY TRACKING EAST ACROSS NORTHERN IA COULD
INTERACT WITH THIS TO HELP SPRING ACTIVITY...BUT IT MAY STRUGGLE
LASTING DEEP INTO THE EVE AT LEAST WITH STRONG POTENTIAL GIVEN THE
DIURNAL HEATING OF THE DAY HAVING WANED. CONVECTIVE ALLOWING
GUIDANCE HAS QUITE A BIT OF RANGE IN SOLUTIONS...WHICH DOES NOT
HELP TO BOLSTER CONFIDENCE ANY.
LAPS AND RAP ANALYSIS AND SOUNDINGS INDICATE LARGE VALUES OF DCAPE
/1100+ J/KG/ WHICH COMBINED WITH PRECIPITATION LOADING CONCERNS
COULD FAVOR ISOLATED WET MICROBURSTS IN ANY STORMS...WHICH REMAINS
THE PRIMARY CONCERN. DEEP LAYER SHEAR IS SLOWLY INCREASING JUST
NOW APPROACHING 30 KT NEAR THE IL/WI BORDER...BUT IN GENERAL
REMAINS WEAK ELSEWHERE. OBVIOUSLY THE HIGH PWATS CONTINUE TO
SUPPORT HEAVY RAIN IN ANY STORM.
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 20Z...
* GUSTY SW WINDS BETWEEN 20-25KT WITH A FEW GUSTS TO 30 KT THRU
EARLY THIS EVE.
* ISO SHRA/TSRA DEVELOPING...BEST TIMING FOR STRONGER TSRA WOULD
BE AFT 21Z THRU 01Z.
* WIND DIR SHIFTING FROM WEST TO NORTH THIS EVENING. THEN WINDS
STEADILY TURN NORTHEAST BY DAYBREAK SAT. SPEEDS TONIGHT THRU
MIDDAY SAT WILL GENERALLY BE 7-10KT.
BEACHLER
//DISCUSSION...UPDATED 18Z...
ATMOSPHERE OVER NORTHERN IL/NORTHWEST IN BEGINNING TO BECOME
UNSTBALE AND PRIMED FOR ISOLATED SHOWERS AND THUNDERSTORMS TO
DEVELOP. FORECAST GUIDANCE CONTINUES TO FAVOR STEADILY INCREASED
COVERAGE/INTENSITY OF THUNDERSTORMS BY 20-21Z. CUMULUS CLOUDS WILL
THICKEN AND BUILD...AS THE CONVECTIVE POTENTIAL INCREASES. ALL OF
THIS ACTIVITY WILL DEVELOP AHEAD OF THE FRONTAL BOUNDARY...WITH
BREEZY CONDITIONS FROM THE SOUTHWEST. WINDS WILL GENERALLY BE THRU
FRONTAL PASSAGE AND WITH PRECIP ARND 20-25KT. THEN BY 00-01Z TSRA
COVERAGE WILL BEGIN TO DIMINISH AND SHIFT TO THE SOUTHEAST OF TAF
SITES. EXPECT BY 02Z TSRA TO HAVE COME TO AN END WITH WINDS
TURNING NORTH/NORTHEAST OVERNIGHT. THE GRADIENT BRIEFLY DIMINISHES
LATE TONIGHT...WITH WINDS POSSIBLY COMING DOWN TO LESS THAN 7KT.
SKIES WILL BECOME PARTLY CLOUDY WITH JUST A CIRRUS SHIELD
OVERNIGHT. JUST AFT DAYBREAK SAT WIND SPEEDS WILL INCREASE TO
12-15KT WITH MOSTLY CLEAR SKIES...THEN EXPECT DIURNAL CUMULUS
CLOUDS TO DEVELOP WITH BASES ARND 4KFT AGL...THIS SHUD HELP TO
TRIM WINDS BACK TO ARND 10KT.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM/HIGH CONFIDENCE IN SCT TSRA THIS AFTERNOON THRU EARLY EVENING.
* MEDIUM CONFIDENCE IN TIMING OF ARRIVAL/ENDING AT ORD/MDW.
* HIGH CONFIDENCE IN WIND DIR/SPEED/GUSTS.
* HIGH CONFIDENCE IN WINDS TURNING NORTHEAST BY DAYBREAK SAT.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...VFR. WX NIL.
SUNDAY...CHANCE OF TSRA AFTERNOON THROUGH OVERNIGHT.
MONDAY THROUGH WEDNESDAY...PERIODIC CHANCES TSRA.
THURSDAY...VFR. WX NIL.
KREIN
&&
.MARINE...
300 AM CDT
A BROAD RIDGE OF HIGH PRESSURE EXTENDS FROM THE SOUTH HIGH PLAINS
THROUGH THE OHIO VALLEY. THIS RIDGE WILL SAG SOUTHEAST AND STALL
OUT OVER THE GULF COAST REGION LATE FRIDAY. MEANWHILE...LOW
PRESSURE OVER JAMES BAY WILL DEEPEN SLIGHTLY AS IT TRACKS EAST TO
NORTHERN QUEBEC...WHILE DRAGGING A COLD FRONT SOUTH ACROSS THE LAKE
FRIDAY. SOUTHWEST WINDS WILL INCREASE TO AROUND 30KT OVER MUCH OF
THE LAKE TODAY AS THE GRADIENT STRENGTHENS IN ADVACE OF THE COLD
FRONT. WINDS WILL THEN SHIFT TO MORE NORTHERLY BEHIND THE
FRONT...TEMPORARILY WEAKENING FOR A BRIEF PERIOD FRIDAY NIGHT. A
SECONDARY SURGE OF COOLER AIR WILL PUSH DOWN THE LAKE LATE FRIDAY
NIGHT AND SATURDAY STRENGTHENING THE WINDS TO AROUND 25KT WHILE
VEERING THROUGH NORTHERLY TO NORTHEASTERLY. AS HIGH PRESSURE
BUILDS FROM CENTRAL CANADA INTO THE UPPER MISSISSIPPI VALLEY AND
WESTERN GREAT LAKES...WINDS WILL THEN VEER EASTERLY OVER THE
LAKE...WHILE REMAINING RATHER BRISK.
KREIN
&&
.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.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
240 PM CDT FRI JUL 19 2013
.MESOSCALE DISCUSSION...
239 PM CDT
CONTINUING TO MONITOR CONVECTIVE CHANCES THIS AFTERNOON INTO EARLY
EVENING WITH TRENDS SLOW TO GO THUS FAR AND CONTINUING TO APPEAR
THAT ANY SEVERE THREAT WOULD BE ISOLATED IN COVERAGE.
AS THE UPPER TROUGH CONTINUES TO DIG INTO THE FAR NORTHERN GREAT
LAKES THIS AFTERNOON...A NARROW PLUME OF DEEPER MOISTURE IN
ADVANCE AS SEEN ON WATER VAPOR HAS MOVED EAST INTO NORTHERN IL.
THERE HAS BEEN ACCAS AND AGITATED CU WITHIN THIS STREAM...ALONG
WITH SPORADIC ISOLATED SHOWERS ACROSS SOUTHERN WI AND NOW INTO
NORTHERN BOONE COUNTY IL. SUBTLE PRE-FRONTAL SURFACE CONVERGENCE
IS NOTED IN OBSERVATIONS UNDER THIS...BUT IT HAS BECOME
PROGRESSIVELY LESS CONVERGENT AS THE BOUNDARY LAYER HAS BECOME
WELL-MIXED. GIVEN THAT AN NO NOTICEABLE TRENDS ON SATELLITE OR
RADAR DO NOT FORESEE ANY WIDESPREAD CONVECTIVE GROWTH ON
THIS...ALTHOUGH ISOLATED TO SCATTERED STORMS COULD DEVELOP OR
FESTER...PROBABLY MOST FAVORED ACROSS FAR NORTHEAST IL.
FURTHER TO THE SOUTH A REMNANT ELEVATED OUTFLOW AS SEEN EARLIER
ON SATELLITE AND RADAR HAS STALLED ACROSS FAR NORTHERN IN
SOUTHWEST OVER KANKAKEE AND PONTIAC. THIS HAS TRIGGERED SOME CU
WITH BETTER VERTICAL GROWTH ALONG WITH SHOWERS NOW BEING SEEN
ALONG THE IN/MI BORDER WHERE CONVERGENCE APPEARS MORE DEFINED ON
STREAMLINE ANALYSIS. AN AREA OF 73-75 DEW POINTS ACROSS EAST
CENTRAL IL IS FEEDING INTO THIS AREA LEADING TO MLCAPES OF
3000-3500 J/KG. SIMILAR HERE...ISOLATED TO SCATTERED STORM
DEVELOPMENT COULD BE SEEN...WITH SLOW MOVING CELLS IF ANYTHING CAN
DEVELOP AS THE ACTIVITY IS FURTHER REMOVED FROM THE BETTER
STEERING FLOW TO THE NORTH.
OVERALL IT IS TRENDING THAT STORM CHANCES MAY BE BEST IN THE
FORECAST AREA JUST AHEAD OF THE COOL FRONT WHICH AS OF 230 PM IS
DRAPED FROM NORTHERN LAKE MI TO JUST SOUTH OF LA CROSSE WI. EVEN
THEN THE COVERAGE COULD BE LIMITED. TOWERING CU HAS BEEN SEEN
ALONG THIS AND THIS MAY FURTHER GROW AS THE FRONT UNDERCUTS THE
AFOREMENTIONED DEEPER MOISTURE ALOFT BY LATE THIS AFTERNOON.
SUBTLE SHORT WAVE ENERGY TRACKING EAST ACROSS NORTHERN IA COULD
INTERACT WITH THIS TO HELP SPRING ACTIVITY...BUT IT MAY STRUGGLE
LASTING DEEP INTO THE EVE AT LEAST WITH STRONG POTENTIAL GIVEN THE
DIURNAL HEATING OF THE DAY HAVING WANED. CONVECTIVE ALLOWING
GUIDANCE HAS QUITE A BIT OF RANGE IN SOLUTIONS...WHICH DOES NOT
HELP TO BOLSTER CONFIDENCE ANY.
LAPS AND RAP ANALYSIS AND SOUNDINGS INDICATE LARGE VALUES OF DCAPE
/1100+ J/KG/ WHICH COMBINED WITH PRECIPITATION LOADING CONCERNS
COULD FAVOR ISOLATED WET MICROBURSTS IN ANY STORMS...WHICH REMAINS
THE PRIMARY CONCERN. DEEP LAYER SHEAR IS SLOWLY INCREASING JUST
NOW APPROACHING 30 KT NEAR THE IL/WI BORDER...BUT IN GENERAL
REMAINS WEAK ELSEWHERE. OBVIOUSLY THE HIGH PWATS CONTINUE TO
SUPPORT HEAVY RAIN IN ANY STORM.
MTF
&&
.DISCUSSION...
1138 AM CDT
THE MORNING CONVECTION AND THE ASSOCIATED CLOUD COVER HAVE
DISSIPATED OVER THE PAST COUPLE HOURS ACROSS SOUTHERN WISCONSIN. IT
APPEARS AN OUTFLOW BOUNDARY...LIKELY ELEVATED IS PUSHING ACROSS
NORTHERN ILLINOIS AT THIS TIME. WITH SKIES REMAINING CLEAR ACROSS THE
REGION...TEMPERATURES ARE QUICKLY WARMING INTO THE LOW 90S EARLY
THIS MORNING. WITH EVEN WARM 925 MB TEMPERATURES TODAY NEAR 27
DEGREES C...PER 12 UTC DVN RAOB...I SEE NO REASON WHY TEMPERATURES
WILL NOT WARM INTO THE MIDDLE 90S BY EARLY AFTERNOON. THEREFORE...I
WARMED TEMPERATURES A FEW DEGREES. THE INCREASING SOUTHWESTERLY
WINDS SHOULD HELP MIX OUT DEW POINTS SOME...RESULTING IN SOME
SLIGHTLY LOWER DEW POINTS IN THE UPPER 60S TO THE LOW 70S.
THEREFORE...HEAT INDEX VALUES STILL APPEAR TO PEAK NEAR 105 THIS
AFTERNOON.
IT APPEARS CONVECTION WILL FIRE UP ACROSS NORTHERN ILLINOIS AFTER 19
UTC. MODIFYING DVN 12 UTC RAOB FOR CURRENT CONDITIONS INDICATE VERY
LITTLE CAP REMAINING ACROSS THE AREA WITH SB CAPE AROUND 2800 J/KG.
THEREFORE...IT IS NOT SURPRISING THAT THE REGIONAL SATELLITE IMAGERY
SHOWS AN AREA OF CLOUD COVER WITH INCREASING AGITATION ACROSS
PORTIONS OF IOWA. THIS AREA ALSO COINCIDES WITH SOME ENHANCED
BOUNDARY LAYER CONVERGENCE JUST AHEAD OF THE SURFACE COLD FRONT.
THIS ACTIVITY SHOULD CONTINUE TO DEVELOP AND MOVE TOWARDS MY
NORTHERN COUNTIES AFTER 19 OR 20 UTC AS THE SURFACE FRONT CONTINUES
TO DROP SOUTHWARD. ADDITIONAL ISOLATED TO SCATTERED CONVECTION COULD
ALSO DEVELOP FARTHER SOUTH AND EAST ACROSS THE SOUTHERN SUBURBS OF
CHICAGO AND INTO NORTHWESTERN INDIANA THIS AFTERNOON...IN
ASSOCIATION WITH INCREASING BOUNDARY LAYER CONVERGENCE ALONG A
PREFRONTAL TROUGH.
IT APPEARS THE MAIN SEVERE THREAT FROM THIS ACTIVITY WILL BE
DAMAGING WIND GUSTS. DEEP LAYER SHEAR REMAINS RELATIVELY WEAK...20
TO 25 KT...MAINLY DUE TO THE STRONGER MID LEVEL FLOW REMAINING TO
THE NORTH BEHIND THE FRONT. HOWEVER...WET OR EVEN HYBRID
MICROBURSTS ARE LIKELY WITH THIS ACTIVITY WITH LAYER THETA-E
DIFFERENCES IN EXCESS OF 20 DEGREES C.
THE OTHER THREAT WILL BE THAT OF TORRENTIAL DOWNPOURS WITH THIS
ACTIVITY. PWATS ARE PROGGED TO BY AROUND 2 INCHES...THEREFORE THESE
STORMS WILL HAVE PLENTY OF HIGH THETA-E AIR TO WORK WITH. RAINFALL
RATES IN SOME OF THESE STORMS COULD EASILY EXCEED AN INCH OR TWO AN
HOUR...WHICH COULD RESULT IN SOME LOCALIZED HYDRO
ISSUES...ESPECIALLY IF THIS OCCURS OVER THE URBAN AREAS. I DECIDED
TO ADD HEAVY RAINFALL TO THE GRIDS EARLY THIS EVENING...BUT I KEPT
IT SOUTH OF CHICAGO...MAINLY ACROSS EAST CENTRAL ILLINOIS AND
NORTHWESTERN INDIANA WHERE THE CONVECTIVE ACTIVITY COULD LINGER
THIS EVENING. STORM MOTIONS SHOULD BE TO THE EAST AROUND 25
KT...SO THE POTENTIAL FOR SOME TRAINING CELLS COULD RESULT IN
LOCAL HEAVY RAINFALL AMOUNTS.
KJB
//PREV DISCUSSION...
337 AM CDT
FORECAST CHALLENGES THIS MORNING INCLUDE HEAT AND THUNDERSTORMS
CHANCES TODAY...FOLLOWED BY POPS/TSTORM CHANCES NEXT WEEK AS WE GET
INTO A POTENTIALLY MORE UNSETTLED PATTERN AFTER A RETURN TO MORE
SEASONABLE TEMPS THIS WEEKEND.
TRICKY FORECAST FOR HEAT TODAY AS NORTHERN AND NORTHWESTERN PORTIONS
OF THE CWA WILL SEE CONVECTIVE POTENTIAL RAMPING UP BY LATE MORNING
WITH CLOUDINESS INCREASING. IN ADDITION...GOES SOUNDER PWAT IMAGERY
SHOWS A SWATH OF LOWER PWAT AIR UPSTREAM AHEAD OF THE FRONT AND THIS
WAS CONFIRMED IN 00Z SOUNDINGS WITH 925MB DEWPOINTS 5C+ LOWER THAN
ILX/DVN. IN THIS REGION...STRONGER SOUTHWEST WINDS ALLOWED DEWPOINTS
TO MIX OUT IN THE 60S THURS AFTERNOON AND AM CONCERNED WE COULD SEE
SOMETHING SIMILAR HAPPEN HERE TODAY MAKING IT HARD FOR HEAT INDICES
TO REACH 100F. RUC...WHICH DID SEEM TO INITIALIZE THIS DRIER AIR OK
SHOWS IT GETTING PINCHED OFF THIS MORNING WITH NO APPRECIABLE DROP
IN DEWPOINTS TODAY. IN REALITY...WE`RE PROBABLY TALKING ABOUT THE
DIFFERENCE BETWEEN HEAT INDICES IN THE MID-UPPER 90S VS UP TO
100-105 WHICH IS PRETTY TRIVIAL DETAIL AT THIS POINT. NO SIGNIFICANT
CHANGES WERE MADE TO FORECAST TEMPS OR HEAT INDICES...SO NO PLANS TO
ALTER HEADLINES AT THIS TIME.
CONVECTION HAS FINALLY BEGUN TO LIGHT UP DOWN THE FRONT OVER
SOUTHERN MN WHICH GUIDANCE HAS BEEN SUGGESTING WOULD HAVE HAPPENED
HOURS AGO. MANY OF THE CONVECTIVE ALLOWING MODELS (CAMS) HOLD ONTO
THIS CONVECTION OR ITS OUTFLOW THROUGH THE MORNING WITH
RE-INTENSIFICATION TAKING PLACE LATER THIS MORNING OVER SOUTHERN WI
INTO N IL AS THE BOUNDARY LAYER RAPIDLY DESTABILIZES. GLANCING BLOW
OF MID LEVEL HEIGHT FALLS ALONG WITH APPROACHING COLD FRONT AND
STRONG INSTABILITY FAVOR SCATTERED TO POTENTIALLY NUMEROUS
THUNDERSTORMS MOVING ACROSS THE AREA THIS AFTERNOON AND LINGERING
INTO THIS EVENING SOUTH. CERTAINLY INSTABILITY WILL NOT BE
LACKING...BUT GUIDANCE STRONGLY SUGGESTS THAT THE STRONGER FLOW
ALOFT WILL LAG BEHIND THE FRONT AND CONVECTION TODAY WITH 0-6KM
SHEAR MAGNITUDE OF GENERALLY LESS THAN 20KT. GIVEN THE WEAK
SHEAR...VERY WARM TEMPS ALOFT (WET BULB ZERO RISING TO OVER 14KFT)
AND WEAK MID LEVEL LAPSE RATES THE THREAT OF HAIL LOOKS MINIMAL. THE
WEAK SHEAR ALSO SUGGESTS MINIMAL STORM SCALE ORGANIZATION OR
LONGEVITY WITH ANY SEVERE THREAT LIKELY LIMITED TO SPOTTY PULSE TYPE
MICROBURSTS WITH WHAT LIMITED SEVERE THREAT THERE IS LIKELY
DIMINISHING FURTHER WITH SUNSET.
NORTHERLY WINDS BEHIND THE FRONT LATER TONIGHT AND SATURDAY WILL
GRADUALLY ADVECT IN LOWER DEWPOINTS AND COOLER TEMPERATURES...BUT AS
IS TYPICAL WITH SUMMERTIME FRONT THE ARRIVAL OF THE COOLER/DRIER AIR
WILL BE A GRADUAL PROCESS BEHIND THE FRONT. BY SUNDAY AND INTO THE
FIRST HALF OF NEXT WEEK WITH A LOW AMPLITUDE WEST-NORTHWEST FLOW
OVER THE REGION WITH MULTIPLE WEAK SHORTWAVES RIDING THIS FLOW INTO
THE AREA BRINGING AT LEAST PERIODIC CHANCES OF SHOWERS AND
THUNDERSTORMS. UNFORTUNATELY MODELS ARE ALL OVER THE PLACE IN TIMING
AND INTENSITY OF THESE LOW AMPLITUDE FEATURES AND RESULTANT MCS
ACTIVITY LENDING TO A LOW CONFIDENCE FORECAST. GIVEN THE LOW
PREDICTABILITY OF THESE FEATURES WAS LEFT WITH LITTLE CHOICE THAN TO
PAINT PERIOD AFTER PERIOD IN THE FORECAST WITH CHANCES POPS...WHEN
IN REALITY MUCH OF THE PERIOD WILL BE DRY. TEMPERATURES GENERALLY
LOOK TO BE FAIRLY SEASONABLE THROUGH THIS PERIOD...WITH DAYTIME
TEMPS LIKELY AFFECTED TO A LARGE EXTENT BY COVERAGE OF PRECIP AND
CLOUDINESS.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* GUSTY SW WINDS BETWEEN 20-25KT WITH A FEW GUSTS TO 30 KT THRU
EARLY THIS EVE.
* ISO SHRA/TSRA DEVELOPING...BEST TIMING FOR STRONGER TSRA WOULD
BE AFT 21Z THRU 01Z.
* WIND DIR SHIFTING FROM WEST TO NORTH THIS EVENING. THEN WINDS
STEADILY TURN NORTHEAST BY DAYBREAK SAT. SPEEDS TONIGHT THRU
MIDDAY SAT WILL GENERALLY BE 7-10KT.
BEACHLER
//DISCUSSION...UPDATED 18Z...
ATMOSPHERE OVER NORTHERN IL/NORTHWEST IN BEGINNING TO BECOME
UNSTBALE AND PRIMED FOR ISOLATED SHOWERS AND THUNDERSTORMS TO
DEVELOP. FORECAST GUIDANCE CONTINUES TO FAVOR STEADILY INCREASED
COVERAGE/INTENSITY OF THUNDERSTORMS BY 20-21Z. CUMULUS CLOUDS WILL
THICKEN AND BUILD...AS THE CONVECTIVE POTENTIAL INCREASES. ALL OF
THIS ACTIVITY WILL DEVELOP AHEAD OF THE FRONTAL BOUNDARY...WITH
BREEZY CONDITIONS FROM THE SOUTHWEST. WINDS WILL GENERALLY BE THRU
FRONTAL PASSAGE AND WITH PRECIP ARND 20-25KT. THEN BY 00-01Z TSRA
COVERAGE WILL BEGIN TO DIMINISH AND SHIFT TO THE SOUTHEAST OF TAF
SITES. EXPECT BY 02Z TSRA TO HAVE COME TO AN END WITH WINDS
TURNING NORTH/NORTHEAST OVERNIGHT. THE GRADIENT BRIEFLY DIMINISHES
LATE TONIGHT...WITH WINDS POSSIBLY COMING DOWN TO LESS THAN 7KT.
SKIES WILL BECOME PARTLY CLOUDY WITH JUST A CIRRUS SHIELD
OVERNIGHT. JUST AFT DAYBREAK SAT WIND SPEEDS WILL INCREASE TO
12-15KT WITH MOSTLY CLEAR SKIES...THEN EXPECT DIURNAL CUMULUS
CLOUDS TO DEVELOP WITH BASES ARND 4KFT AGL...THIS SHUD HELP TO
TRIM WINDS BACK TO ARND 10KT.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM/HIGH CONFIDENCE IN SCT TSRA THIS AFTERNOON THRU EARLY EVENING.
* MEDIUM CONFIDENCE IN TIMING OF ARRIVAL/ENDING AT ORD/MDW.
* HIGH CONFIDENCE IN WIND DIR/SPEED/GUSTS.
* HIGH CONFIDENCE IN WINDS TURNING NORTHEAST BY DAYBREAK SAT.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...VFR. WX NIL.
SUNDAY...CHANCE OF TSRA AFTERNOON THROUGH OVERNIGHT.
MONDAY THROUGH WEDNESDAY...PERIODIC CHANCES TSRA.
THURSDAY...VFR. WX NIL.
KREIN
&&
.MARINE...
300 AM CDT
A BROAD RIDGE OF HIGH PRESSURE EXTENDS FROM THE SOUTH HIGH PLAINS
THROUGH THE OHIO VALLEY. THIS RIDGE WILL SAG SOUTHEAST AND STALL
OUT OVER THE GULF COAST REGION LATE FRIDAY. MEANWHILE...LOW
PRESSURE OVER JAMES BAY WILL DEEPEN SLIGHTLY AS IT TRACKS EAST TO
NORTHERN QUEBEC...WHILE DRAGGING A COLD FRONT SOUTH ACROSS THE LAKE
FRIDAY. SOUTHWEST WINDS WILL INCREASE TO AROUND 30KT OVER MUCH OF
THE LAKE TODAY AS THE GRADIENT STRENGTHENS IN ADVACE OF THE COLD
FRONT. WINDS WILL THEN SHIFT TO MORE NORTHERLY BEHIND THE
FRONT...TEMPORARILY WEAKENING FOR A BRIEF PERIOD FRIDAY NIGHT. A
SECONDARY SURGE OF COOLER AIR WILL PUSH DOWN THE LAKE LATE FRIDAY
NIGHT AND SATURDAY STRENGTHENING THE WINDS TO AROUND 25KT WHILE
VEERING THROUGH NORTHERLY TO NORTHEASTERLY. AS HIGH PRESSURE
BUILDS FROM CENTRAL CANADA INTO THE UPPER MISSISSIPPI VALLEY AND
WESTERN GREAT LAKES...WINDS WILL THEN VEER EASTERLY OVER THE
LAKE...WHILE REMAINING RATHER BRISK.
KREIN
&&
.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 TOPEKA KS
1237 PM CDT FRI JUL 19 2013
...UPDATE TO AVIATION...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 356 AM CDT FRI JUL 19 2013
EARLY THIS MORNING A BROAD UPPER LEVEL RIDGE AXIS EXTENDED FROM
COAST TO COAST ACROSS THE SOUTHERN CONUS. A CUT OFF UPPER LOW WAS
DRIFTING WEST ACROSS THE NORTHERN GULF OF MEXICO. A SECOND CUT OFF
LOW WAS DRIFTING SOUTHWEST INTO NORTHWEST MEXICO. AN UPPER LEVEL
TROUGH WAS MOVING EAST ACROSS THE NORTHERN PLAINS INTO THE UPPER
MIDWEST.
TODAY AND TONIGHT...THE UPPER RIDGE ACROSS THE WESTERN CONUS WILL
AMPLIFY CAUSING THE FLOW ACROSS THE CENTRAL PLAINS TO BECOME
SLIGHTLY MORE NORTHWESTERLY. THE BEST UPPER LEVEL ASCENT AHEAD OF
THE H5 TROUGH MOVING ACROSS THE NORTHERN PLAINS WILL REMAIN WELL
NORTHEAST OF THE CWA. A WEAK COLD FRONT WILL MOVE SOUTHWARD ACROSS
NE INTO THE NORTHERN COUNTIES OF THE CWA BY 21Z. CONVERGENCE ALONG
THIS FRONT MAY CAUSE ISOLATED SHOWERS AND THUNDERSTORMS TO DEVELOP
ACROSS THE NORTHERN COUNTIES OF THE CWA. THE 00Z GFS AND TWO
MESOSCALE MODELS...THE RAP AND NON-HYDROSTATIC WRF ARE SHOWING A
LINE OF SCATTERED TO NUMEROUS SHOWERS DEVELOPING AHEAD OF THE FRONT
AND PUSHING SOUTHEAST ACROSS THE REMAINDER OF THE CWA THROUGH THE
EVENING HOURS. WHILE THE ECMWF AND 00Z NAM SHOW ONLY ISOLATED
SHOWERS DEVELOPING ACROSS THE NORTHERN HALF OF THE CWA LATE FRIDAY
AFTERNOON AND EVENING. I`M LEANING MORE TOWARDS THE NAM AND ECMWF
SINCE THERE WILL BE LITTLE IN THE WAY OF UPPER LEVEL SUPPORT SINCE
THE MAIN H5 TROUGH WILL BE DIGGING SOUTHEAST ACROSS THE MIDWEST INTO
THE GREAT LAKES STATES. ATTM...I`LL KEEP THE LOW CHANCE POPS OF 25
TO 35 PERCENT ACROSS MUCH OF THE CWA TONIGHT. THE PRECIP SHOULD END
FROM NORTH TO SOUTH DURING THE EARLY MORNING HOURS OF SATURDAY AS
THE COLD FRONT PUSHES SOUTH OF THE CWA BY 12Z SAT.
SKIES WILL START OUT MOSTLY SUNNY ACROSS THE CWA WITH AN INCREASE IN
CU DURING THE AFTERNOON HOURS. HIGHS WILL REACH THE MID TO UPPER 90S
ACROSS THE CWA. SURFACE DEWPOINTS WILL DECREASE SLIGHTLY DURING THE
AFTERNOON HOURS AS THE BOUNDARY LAYER MIXES DEEPER ACROSS THE
PLAINS. I HAVE AFTERNOON DEWPOINTS IN THE LOWER TO MID 60S...WHICH
SHOULD KEEP HEAT INDICES NEAR THE HIGH TEMPERATURES IN THE UPPER
90S. HEAT INDICES MAY REACH AROUND 100 DEGREES ACROSS THE EASTERN
COUNTIES OF THE CWA.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 356 AM CDT FRI JUL 19 2013
THE FRONT OR ITS REMNANTS WILL LIKELY REMAIN IN THE AREA THROUGH
EARLY NEXT WEEK. WITH WEST TO NORTHWEST FLOW ALOFT ALSO
DOMINATING...A SERIES OF SHORTWAVE TROUGHS WILL MOVE THROUGH THE
FLOW AND ACROSS THE COUNTY WARNING AREA THROUGH THE EXTENDED
PERIODS...ALTHOUGH THE MODELS OFFER DIFFERENT SOLUTIONS ON THE
STRENGTH AND TIMING OF THESE SHORTWAVE TROUGHS. ALTHOUGH WILL GO
WITH POPS THROUGH MOST OF THE FORECAST...THE BETTER CHANCES FOR MORE
ORGANIZED/HIGHER COVERAGE CONVECTIVE EVENTS OCCURS DURING TWO
PERIODS. THE FIRST WILL BE WITH A POSSIBLE MCS LATE SATURDAY
NIGHT/EARLY SUNDAY ACROSS MAINLY THE WESTERN CWA AND WITH THE
PASSAGE OF THE SHORTWAVE TROUGH ON THE NOSE OF VEERING LLVL FLOW AND
STRONGER WARM ADVECTION LATE SUNDAY INTO SUNDAY NIGHT. THIS SHOULD
BE FOLLOWED BY A PERIOD OF LOWER POP CHANCES INTO TUESDAY BEFORE
ANOTHER SHORTWAVE TROUGH PASSES AND FRONT MOVES THROUGH THE AREA
WITHIN ANOTHER REGION OF STRONGER WAA ALONG THE EASTERN PERIPHERY OF
A STRONG THERMAL AXIS. WITH BOUNDARY STILL IN THE AREA/OR JUST
SOUTH...WILL KEEP LOW POPS GOING PORTIONS OF THE CWA ON INTO
THURSDAY HOWEVER. TEMPERATURES OVER THE WEEKEND INTO NEXT WEEK WILL
BE CHALLENGING AS THE COUNTY WARNING AREA WILL OFTEN BE ON THE
EASTERN EDGE OF A STRONG LLVL THERMAL AXIS WITH THE LLVL FLOW
FREQUENTLY VEERED. HOWEVER...CLOUDS AND PERIODIC PRECIP CHANCES WILL
BE OFFSETTING FACTORS. FOR NOW...HIGHS WILL GENERALLY BE IN THE LOW
TO MID 90S THROUGH THE FCST. MONDAY AND TUESDAY WILL LIKELY BE THE
WARMEST DAYS WITH SOME UPPER 90S POSSIBLE IN THE WESTERN/SOUTHWEST
CWA. AT THIS POINT HEAT INDICES ON BOTH OF THOSE DAYS SHOULD BE IN
THE 98 TO 102 DEGREE RANGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1215 PM CDT FRI JUL 19 2013
VFR CONDITIONS AT KTOP/KFOE/KMHK FOR THE NEXT FORECAST PERIOD.
A GRADUAL FROPA LATE THIS AFTERNOON MAINLY AFTER 22Z WILL
VEER WINDS TO THE WEST AND THEN NORTHWEST BY 05Z AT KTOP/KFOE AND
KMHK BY 04Z. TIMING IS APPROXIMATE AS MODELS VARY SLIGHTLY ON THE
SPEED OF THE FRONT. WIDELY SCATTERED TSRA MAY BE POSSIBLE NEAR AND
ALONG THE FRONT AS IT PASSES. INSERTED VCTS FOR THIS
AFTERNOON/EARLY EVENING AT KMHK AND AFT 00Z AT KTOP/KFOE AS
COVERAGE OF TSRA IS LOW. EXPECT LIGHT AND VARIABLE WINDS AFT 04Z
AT TERMINALS WITH A BKN LAYER OF CIRRUS LINGERING THROUGH 18Z.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GARGAN
LONG TERM...63
AVIATION...BOWEN
AREA FORECAST DISCUSSION
NWS TOPEKA KS
500 AM CDT FRI JUL 19 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 356 AM CDT FRI JUL 19 2013
EARLY THIS MORNING A BROAD UPPER LEVEL RIDGE AXIS EXTENDED FROM
COAST TO COAST ACROSS THE SOUTHERN CONUS. A CUT OFF UPPER LOW WAS
DRIFTING WEST ACROSS THE NORTHERN GULF OF MEXICO. A SECOND CUT OFF
LOW WAS DRIFTING SOUTHWEST INTO NORTHWEST MEXICO. AN UPPER LEVEL
TROUGH WAS MOVING EAST ACROSS THE NORTHERN PLAINS INTO THE UPPER
MIDWEST.
TODAY AND TONIGHT...THE UPPER RIDGE ACROSS THE WESTERN CONUS WILL
AMPLIFY CAUSING THE FLOW ACROSS THE CENTRAL PLAINS TO BECOME
SLIGHTLY MORE NORTHWESTERLY. THE BEST UPPER LEVEL ASCENT AHEAD OF
THE H5 TROUGH MOVING ACROSS THE NORTHERN PLAINS WILL REMAIN WELL
NORTHEAST OF THE CWA. A WEAK COLD FRONT WILL MOVE SOUTHWARD ACROSS
NE INTO THE NORTHERN COUNTIES OF THE CWA BY 21Z. CONVERGENCE ALONG
THIS FRONT MAY CAUSE ISOLATED SHOWERS AND THUNDERSTORMS TO DEVELOP
ACROSS THE NORTHERN COUNTIES OF THE CWA. THE 00Z GFS AND TWO
MESOSCALE MODELS...THE RAP AND NON-HYDROSTATIC WRF ARE SHOWING A
LINE OF SCATTERED TO NUMEROUS SHOWERS DEVELOPING AHEAD OF THE FRONT
AND PUSHING SOUTHEAST ACROSS THE REMAINDER OF THE CWA THROUGH THE
EVENING HOURS. WHILE THE ECMWF AND 00Z NAM SHOW ONLY ISOLATED
SHOWERS DEVELOPING ACROSS THE NORTHERN HALF OF THE CWA LATE FRIDAY
AFTERNOON AND EVENING. I`M LEANING MORE TOWARDS THE NAM AND ECMWF
SINCE THERE WILL BE LITTLE IN THE WAY OF UPPER LEVEL SUPPORT SINCE
THE MAIN H5 TROUGH WILL BE DIGGING SOUTHEAST ACROSS THE MIDWEST INTO
THE GREAT LAKES STATES. ATTM...I`LL KEEP THE LOW CHANCE POPS OF 25
TO 35 PERCENT ACROSS MUCH OF THE CWA TONIGHT. THE PRECIP SHOULD END
FROM NORTH TO SOUTH DURING THE EARLY MORNING HOURS OF SATURDAY AS
THE COLD FRONT PUSHES SOUTH OF THE CWA BY 12Z SAT.
SKIES WILL START OUT MOSTLY SUNNY ACROSS THE CWA WITH AN INCREASE IN
CU DURING THE AFTERNOON HOURS. HIGHS WILL REACH THE MID TO UPPER 90S
ACROSS THE CWA. SURFACE DEWPOINTS WILL DECREASE SLIGHTLY DURING THE
AFTERNOON HOURS AS THE BOUNDARY LAYER MIXES DEEPER ACROSS THE
PLAINS. I HAVE AFTERNOON DEWPOINTS IN THE LOWER TO MID 60S...WHICH
SHOULD KEEP HEAT INDICES NEAR THE HIGH TEMPERATURES IN THE UPPER
90S. HEAT INDICES MAY REACH AROUND 100 DEGREES ACROSS THE EASTERN
COUNTIES OF THE CWA.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 356 AM CDT FRI JUL 19 2013
THE FRONT OR ITS REMNANTS WILL LIKELY REMAIN IN THE AREA THROUGH
EARLY NEXT WEEK. WITH WEST TO NORTHWEST FLOW ALOFT ALSO
DOMINATING...A SERIES OF SHORTWAVE TROUGHS WILL MOVE THROUGH THE
FLOW AND ACROSS THE COUNTY WARNING AREA THROUGH THE EXTENDED
PERIODS...ALTHOUGH THE MODELS OFFER DIFFERENT SOLUTIONS ON THE
STRENGTH AND TIMING OF THESE SHORTWAVE TROUGHS. ALTHOUGH WILL GO
WITH POPS THROUGH MOST OF THE FORECAST...THE BETTER CHANCES FOR MORE
ORGANIZED/HIGHER COVERAGE CONVECTIVE EVENTS OCCURS DURING TWO
PERIODS. THE FIRST WILL BE WITH A POSSIBLE MCS LATE SATURDAY
NIGHT/EARLY SUNDAY ACROSS MAINLY THE WESTERN CWA AND WITH THE
PASSAGE OF THE SHORTWAVE TROUGH ON THE NOSE OF VEERING LLVL FLOW AND
STRONGER WARM ADVECTION LATE SUNDAY INTO SUNDAY NIGHT. THIS SHOULD
BE FOLLOWED BY A PERIOD OF LOWER POP CHANCES INTO TUESDAY BEFORE
ANOTHER SHORTWAVE TROUGH PASSES AND FRONT MOVES THROUGH THE AREA
WITHIN ANOTHER REGION OF STRONGER WAA ALONG THE EASTERN PERIPHERY OF
A STRONG THERMAL AXIS. WITH BOUNDARY STILL IN THE AREA/OR JUST
SOUTH...WILL KEEP LOW POPS GOING PORTIONS OF THE CWA ON INTO
THURSDAY HOWEVER. TEMPERATURES OVER THE WEEKEND INTO NEXT WEEK WILL
BE CHALLENGING AS THE COUNTY WARNING AREA WILL OFTEN BE ON THE
EASTERN EDGE OF A STRONG LLVL THERMAL AXIS WITH THE LLVL FLOW
FREQUENTLY VEERED. HOWEVER...CLOUDS AND PERIODIC PRECIP CHANCES WILL
BE OFFSETTING FACTORS. FOR NOW...HIGHS WILL GENERALLY BE IN THE LOW
TO MID 90S THROUGH THE FCST. MONDAY AND TUESDAY WILL LIKELY BE THE
WARMEST DAYS WITH SOME UPPER 90S POSSIBLE IN THE WESTERN/SOUTHWEST
CWA. AT THIS POINT HEAT INDICES ON BOTH OF THOSE DAYS SHOULD BE IN
THE 98 TO 102 DEGREE RANGE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 454 AM CDT FRI JUL 19 2013
EXPECT VFR CONDITIONS THROUGH MOST OF THE NEXT 24 HOURS. THERE MAY
BE SOME ISOLATED TO WIDELY SCATTERED THUNDERSTORMS ACROSS THE TAF
SITES. THERE CONTINUES TO BE UNCERTAINTY IN BOTH TIMING AND
COVERAGE OF ANY THUNDERSTORM DEVELOPMENT AT THE TAF SITES THIS
EVENING. THEREFORE...I DID NOT INCLUDE A VCTS IN THE TAFS. ANY
THUNDERSTORMS MAY BRING BRIEF MVFR CEILINGS AND VISIBILITIES TO THE
TAF SITES THIS EVENING.
GARGAN
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GARGAN
LONG TERM...63
AVIATION...GARGAN
AREA FORECAST DISCUSSION
NWS TOPEKA KS
358 AM CDT FRI JUL 19 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 356 AM CDT FRI JUL 19 2013
EARLY THIS MORNING A BROAD UPPER LEVEL RIDGE AXIS EXTENDED FROM
COAST TO COAST ACROSS THE SOUTHERN CONUS. A CUT OFF UPPER LOW WAS
DRIFTING WEST ACROSS THE NORTHERN GULF OF MEXICO. A SECOND CUT OFF
LOW WAS DRIFTING SOUTHWEST INTO NORTHWEST MEXICO. AN UPPER LEVEL
TROUGH WAS MOVING EAST ACROSS THE NORTHERN PLAINS INTO THE UPPER
MIDWEST.
TODAY AND TONIGHT...THE UPPER RIDGE ACROSS THE WESTERN CONUS WILL
AMPLIFY CAUSING THE FLOW ACROSS THE CENTRAL PLAINS TO BECOME
SLIGHTLY MORE NORTHWESTERLY. THE BEST UPPER LEVEL ASCENT AHEAD OF
THE H5 TROUGH MOVING ACROSS THE NORTHERN PLAINS WILL REMAIN WELL
NORTHEAST OF THE CWA. A WEAK COLD FRONT WILL MOVE SOUTHWARD ACROSS
NE INTO THE NORTHERN COUNTIES OF THE CWA BY 21Z. CONVERGENCE ALONG
THIS FRONT MAY CAUSE ISOLATED SHOWERS AND THUNDERSTORMS TO DEVELOP
ACROSS THE NORTHERN COUNTIES OF THE CWA. THE 00Z GFS AND TWO
MESOSCALE MODELS...THE RAP AND NON-HYDROSTATIC WRF ARE SHOWING A
LINE OF SCATTERED TO NUMEROUS SHOWERS DEVELOPING AHEAD OF THE FRONT
AND PUSHING SOUTHEAST ACROSS THE REMAINDER OF THE CWA THROUGH THE
EVENING HOURS. WHILE THE ECMWF AND 00Z NAM SHOW ONLY ISOLATED
SHOWERS DEVELOPING ACROSS THE NORTHERN HALF OF THE CWA LATE FRIDAY
AFTERNOON AND EVENING. I`M LEANING MORE TOWARDS THE NAM AND ECMWF
SINCE THERE WILL BE LITTLE IN THE WAY OF UPPER LEVEL SUPPORT SINCE
THE MAIN H5 TROUGH WILL BE DIGGING SOUTHEAST ACROSS THE MIDWEST INTO
THE GREAT LAKES STATES. ATTM...I`LL KEEP THE LOW CHANCE POPS OF 25
TO 35 PERCENT ACROSS MUCH OF THE CWA TONIGHT. THE PRECIP SHOULD END
FROM NORTH TO SOUTH DURING THE EARLY MORNING HOURS OF SATURDAY AS
THE COLD FRONT PUSHES SOUTH OF THE CWA BY 12Z SAT.
SKIES WILL START OUT MOSTLY SUNNY ACROSS THE CWA WITH AN INCREASE IN
CU DURING THE AFTERNOON HOURS. HIGHS WILL REACH THE MID TO UPPER 90S
ACROSS THE CWA. SURFACE DEWPOINTS WILL DECREASE SLIGHTLY DURING THE
AFTERNOON HOURS AS THE BOUNDARY LAYER MIXES DEEPER ACROSS THE
PLAINS. I HAVE AFTERNOON DEWPOINTS IN THE LOWER TO MID 60S...WHICH
SHOULD KEEP HEAT INDICES NEAR THE HIGH TEMPERATURES IN THE UPPER
90S. HEAT INDICES MAY REACH AROUND 100 DEGREES ACROSS THE EASTERN
COUNTIES OF THE CWA.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 356 AM CDT FRI JUL 19 2013
THE FRONT OR ITS REMNANTS WILL LIKELY REMAIN IN THE AREA THROUGH
EARLY NEXT WEEK. WITH WEST TO NORTHWEST FLOW ALOFT ALSO
DOMINATING...A SERIES OF SHORTWAVE TROUGHS WILL MOVE THROUGH THE
FLOW AND ACROSS THE COUNTY WARNING AREA THROUGH THE EXTENDED
PERIODS...ALTHOUGH THE MODELS OFFER DIFFERENT SOLUTIONS ON THE
STRENGTH AND TIMING OF THESE SHORTWAVE TROUGHS. ALTHOUGH WILL GO
WITH POPS THROUGH MOST OF THE FORECAST...THE BETTER CHANCES FOR MORE
ORGANIZED/HIGHER COVERAGE CONVECTIVE EVENTS OCCURS DURING TWO
PERIODS. THE FIRST WILL BE WITH A POSSIBLE MCS LATE SATURDAY
NIGHT/EARLY SUNDAY ACROSS MAINLY THE WESTERN CWA AND WITH THE
PASSAGE OF THE SHORTWAVE TROUGH ON THE NOSE OF VEERING LLVL FLOW AND
STRONGER WARM ADVECTION LATE SUNDAY INTO SUNDAY NIGHT. THIS SHOULD
BE FOLLOWED BY A PERIOD OF LOWER POP CHANCES INTO TUESDAY BEFORE
ANOTHER SHORTWAVE TROUGH PASSES AND FRONT MOVES THROUGH THE AREA
WITHIN ANOTHER REGION OF STRONGER WAA ALONG THE EASTERN PERIPHERY OF
A STRONG THERMAL AXIS. WITH BOUNDARY STILL IN THE AREA/OR JUST
SOUTH...WILL KEEP LOW POPS GOING PORTIONS OF THE CWA ON INTO
THURSDAY HOWEVER. TEMPERATURES OVER THE WEEKEND INTO NEXT WEEK WILL
BE CHALLENGING AS THE COUNTY WARNING AREA WILL OFTEN BE ON THE
EASTERN EDGE OF A STRONG LLVL THERMAL AXIS WITH THE LLVL FLOW
FREQUENTLY VEERED. HOWEVER...CLOUDS AND PERIODIC PRECIP CHANCES WILL
BE OFFSETTING FACTORS. FOR NOW...HIGHS WILL GENERALLY BE IN THE LOW
TO MID 90S THROUGH THE FCST. MONDAY AND TUESDAY WILL LIKELY BE THE
WARMEST DAYS WITH SOME UPPER 90S POSSIBLE IN THE WESTERN/SOUTHWEST
CWA. AT THIS POINT HEAT INDICES ON BOTH OF THOSE DAYS SHOULD BE IN
THE 98 TO 102 DEGREE RANGE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1156 PM CDT THU JUL 18 2013
EXPECTING VFR CONDITIONS THROUGH THE AVIATION FORECAST PERIOD. A
VERY WEAK BOUNDARY WILL SLIDE SOUTHWARD INTO NORTHERN KANSAS LATE
IN THE TAF PERIOD...HOWEVER IT IS UNLIKELY THAT IT WILL REACH THE
TERMINALS. WINDS MAY BECOME VERY LIGHT AND VARIABLE AS THE
BOUNDARY APPROACHES. EXPECT A FEW THUNDERSTORMS ALONG OR JUST
NORTH OF THE BOUNDARY...HOWEVER THESE STORMS SHOULD REMAIN NORTH
OF THE TERMINALS UNTIL AFTER THIS FORECAST ISSUANCE.
JL
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GARGAN
LONG TERM...63
AVIATION...LEIGHTON
AREA FORECAST DISCUSSION
NWS GOODLAND KS
212 AM MDT FRI JUL 19 2013
.UPDATE...
ISSUED AT 1105 PM MDT THU JUL 18 2013
CONVECTION OVER PHILLIPS AND LOGAN COUNTIES IN COLORADO IS HAVING
A DIFFICULT TIME MOVING INTO YUMA COUNTY. WILL KEEP A MENTION OF
SOME STORMS THROUGH THE NIGHT THERE GIVEN SOME LOW LEVEL MOISTYRE
CONVERGENCE...THOUGH THE HRRR MODEL NEVER BRINGS PRECIPITATION TO
THE COUNTY THROUGH 12Z. SURFACE TROUGH HAS MOVED THROUGH FLAGLER
AND YUMA...AND WILL ADJUST WIND DIRECTIONS OVER THE WESTERN HALF
OF THE FORECAST AREA.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 228 PM MDT THU JUL 18 2013
AS OF 3 PM CDT...2 PM MDT...SKIES ACROSS THE TRI-STATE AREA WERE
CLEAR. TEMPERATURES HAVE RISEN INTO THE MID 80S TO LOW 90S. GUSTY
SOUTH WINDS CONTINUE THIS AFTERNOON DUE TO A LEE TROUGH OVER CENTRAL
COLORADO AND A HIGH PRESSURE LOCATED TO THE SOUTH. SHOWERS AND
THUNDERSTORMS HAVE DEVELOPED OVER THE ROCKIES THIS AFTERNOON. A COLD
FRONT WAS LOCATED TO THE NORTH...IN THE VICINITY OF THE SOUTH DAKOTA
AND NEBRASKA BORDER AND INTO SOUTHWEST WYOMING.
FOR TONIGHT...MODELS INDICATE THAT SOME OF THE SHOWERS AND STORMS
WILL MOVE TO THE EAST OFF THE TERRAIN. UNFORTUNATELY...MODELS SEEM
PRETTY CONSISTENT IN SHOWING THAT ALL OF THE ACTIVITY WILL DIMINISH
BEFORE MOVING INTO THE REGION. THE WEAK COLD FRONT WILL CONTINUE
MOVING TO THE SOUTH TONIGHT...ENTERING THE REGION AROUND MIDNIGHT
WITH A SLOW MOVEMENT TO THE SOUTH THROUGH THE OVERNIGHT HOURS. A FEW
SHOWERS ARE POSSIBLE ALONG THE FRONT TONIGHT...MAINLY IN SOUTHWEST
NEBRASKA AND NORTHEAST COLORADO. LOW TEMPERATURES TONIGHT SHOULD
FALL INTO THE LOW TO UPPER 60S WITH COOLEST TEMPERATURES EXPECTED
OVER EAST COLORADO. GUSTY SOUTH WINDS WILL DIMINISH THIS EVENING AS
THE PRESSURE GRADIENT RELAXES. A PERIOD OF CALM WINDS IS ANTICIPATED
JUST AHEAD OF THE COLD FRONT BEFORE NORTH TO NORTHEAST WINDS OF 5 TO
15 MPH BEGIN IN THE MORNING HOURS.
FOR TOMORROW...THE WEAK COLD FRONT WILL CONTINUE A SLUGGISH
SOUTHWARD PUSH. HIGHER DEWPOINTS THAN PREVIOUS DAYS ARE EXPECTED TO
POOL ALONG AND JUST AHEAD OF THE FRONT. WITH THE INCREASED MOISTURE
AND HIGH TEMPERATURES CLIMBING INTO THE LOW TO MID 90S AHEAD OF THE
FRONT...INSTABILITY AND FRONTAL SURFACE CONVERGENCE SHOULD BE ENOUGH
FOR SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP. EVEN THOUGH
INSTABILITY WOULD BE ENOUGH TO SUPPORT SOME POSSIBLE SEVERE
THUNDERSTORMS...WEAK LAPSE RATES AND LITTLE SHEAR LEAD ONE TO THINK
THAT WIDESPREAD SEVERE WEATHER IS NOT LIKELY. A STRONG STORM OR TWO
IS POSSIBLE BUT THAT SHOULD BE ABOUT IT. WITH PRECIPITABLE WATER
VALUES AROUND 1.5 INCHES AND SLOW STORM MOTIONS...HEAVY DOWNPOURS
SEEM LIKE A GOOD BET FOR THE STRONGER THUNDERSTORMS. WINDS WILL
SHIFT TO THE EAST BEHIND THE WEAK COLD FRONT.
.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 212 AM MDT FRI JUL 19 2013
GFS HAS TRENDED SLIGHTLY MORE AMPLIFIED AND LESS PROGRESSIVE WITH
THE UPPER LEVEL RIDGE IN THE WEST. THIS KEEPS OUR AREA IN
NORTHWESTERLY FLOW ALOFT WITH EMBEDDED WEAK AND DIFFICULT TO RESOLVE
SHORTWAVES RESULTING IN SOME CONVECTION TUESDAY THROUGH THURSDAY. IN
CONTRAST...ECMWF HAS BEEN CONSISTENT WITH EXPANDING THE UPPER RIDGE
FURTHER EAST AND HAS MORE DRAMATIC 500 MB HEIGHT RISES THE MIDDLE
OF NEXT WEEK...LEADING TO SOME UNCERTAINTY. THE MOST PRONOUNCED
SHORTWAVE IN NORTHWESTERLY FLOW ALOFT IS SHOWN BY BOTH GFS AND
ECMWF AND WILL PASS THROUGH LATE TUESDAY. GFS IS STRONGEST WITH
DEPICTING AN ASSOCIATED SURFACE BOUNDARY THAT MOVES INTO THE
FORECAST AREA TUESDAY EVENING. ADDITIONALLY...COLUMN MOISTURE
INCREASES WITH PWAT VALUES REACHING NEAR 1.5 INCHES. THIS IS A
CHANGE FROM THE PREVIOUS FORECAST AND HAS REQUIRED THE
INTRODUCTION OF SLIGHT CHANCE POP FOR TUESDAY EVENING/OVERNIGHT.
ACCEPTED CR INITIAL TEMPERATURE GRIDS WHICH ARE A REASONABLY GOOD
COMPROMISE BETWEEN THE COOLER MEX MOS MID WEEK AND THE HOTTER
PATTERN THAT ECMWF IS SHOWING.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1105 PM MDT THU JUL 18 2013
SURFACE TROUGH WILL MOVE EAST THROUGH EASTERN COLORADO...AND WILL
REACH KGLD AROUND 09Z. THIS WILL SWITCH THE SURFACE WINDS TO THE
WEST. EXPECT WIND SHIFT AT KMCK AROUND 12Z. VFR CONDITIONS WILL
CONTINUE THROUGH THE PERIOD...BUT EXPECT CONVECTION TO DEVELOP
AFTER 18Z. THERE WILL BE CHANCE OF THUNDERSTORMS AT BOTH
KGLD/KMCK...BUT CONFIDENCE IS NOT HIGH ENOUGH TO INDICATE STORMS
IN THE TAFS. IF STORMS DO MOVE OVER THE SITES...VISIBILITIES WILL
DROP TO MVFR OR LOWER IN BRIEF HEAVY RAIN.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...MENTZER
SHORT TERM...RRH
LONG TERM...BRB
AVIATION...MENTZER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1105 PM MDT THU JUL 18 2013
.UPDATE...
ISSUED AT 1105 PM MDT THU JUL 18 2013
CONVECTION OVER PHILLIPS AND LOGAN COUNTIES IN COLORADO IS HAVING
A DIFFICULT TIME MOVING INTO YUMA COUNTY. WILL KEEP A MENTION OF
SOME STORMS THROUGH THE NIGHT THERE GIVEN SOME LOW LEVEL MOISTYRE
CONVERGENCE...THOUGH THE HRRR MODEL NEVER BRINGS PRECIPITATION TO
THE COUNTY THROUGH 12Z. SURFACE TROUGH HAS MOVED THROUGH FLAGLER
AND YUMA...AND WILL ADJUST WIND DIRECTIONS OVER THE WESTERN HALF
OF THE FORECAST AREA.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 228 PM MDT THU JUL 18 2013
AS OF 3 PM CDT...2 PM MDT...SKIES ACROSS THE TRI-STATE AREA WERE
CLEAR. TEMPERATURES HAVE RISEN INTO THE MID 80S TO LOW 90S. GUSTY
SOUTH WINDS CONTINUE THIS AFTERNOON DUE TO A LEE TROUGH OVER CENTRAL
COLORADO AND A HIGH PRESSURE LOCATED TO THE SOUTH. SHOWERS AND
THUNDERSTORMS HAVE DEVELOPED OVER THE ROCKIES THIS AFTERNOON. A COLD
FRONT WAS LOCATED TO THE NORTH...IN THE VICINITY OF THE SOUTH DAKOTA
AND NEBRASKA BORDER AND INTO SOUTHWEST WYOMING.
FOR TONIGHT...MODELS INDICATE THAT SOME OF THE SHOWERS AND STORMS
WILL MOVE TO THE EAST OFF THE TERRAIN. UNFORTUNATELY...MODELS SEEM
PRETTY CONSISTENT IN SHOWING THAT ALL OF THE ACTIVITY WILL DIMINISH
BEFORE MOVING INTO THE REGION. THE WEAK COLD FRONT WILL CONTINUE
MOVING TO THE SOUTH TONIGHT...ENTERING THE REGION AROUND MIDNIGHT
WITH A SLOW MOVEMENT TO THE SOUTH THROUGH THE OVERNIGHT HOURS. A FEW
SHOWERS ARE POSSIBLE ALONG THE FRONT TONIGHT...MAINLY IN SOUTHWEST
NEBRASKA AND NORTHEAST COLORADO. LOW TEMPERATURES TONIGHT SHOULD
FALL INTO THE LOW TO UPPER 60S WITH COOLEST TEMPERATURES EXPECTED
OVER EAST COLORADO. GUSTY SOUTH WINDS WILL DIMINISH THIS EVENING AS
THE PRESSURE GRADIENT RELAXES. A PERIOD OF CALM WINDS IS ANTICIPATED
JUST AHEAD OF THE COLD FRONT BEFORE NORTH TO NORTHEAST WINDS OF 5 TO
15 MPH BEGIN IN THE MORNING HOURS.
FOR TOMORROW...THE WEAK COLD FRONT WILL CONTINUE A SLUGGISH
SOUTHWARD PUSH. HIGHER DEWPOINTS THAN PREVIOUS DAYS ARE EXPECTED TO
POOL ALONG AND JUST AHEAD OF THE FRONT. WITH THE INCREASED MOISTURE
AND HIGH TEMPERATURES CLIMBING INTO THE LOW TO MID 90S AHEAD OF THE
FRONT...INSTABILITY AND FRONTAL SURFACE CONVERGENCE SHOULD BE ENOUGH
FOR SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP. EVEN THOUGH
INSTABILITY WOULD BE ENOUGH TO SUPPORT SOME POSSIBLE SEVERE
THUNDERSTORMS...WEAK LAPSE RATES AND LITTLE SHEAR LEAD ONE TO THINK
THAT WIDESPREAD SEVERE WEATHER IS NOT LIKELY. A STRONG STORM OR TWO
IS POSSIBLE BUT THAT SHOULD BE ABOUT IT. WITH PRECIPITABLE WATER
VALUES AROUND 1.5 INCHES AND SLOW STORM MOTIONS...HEAVY DOWNPOURS
SEEM LIKE A GOOD BET FOR THE STRONGER THUNDERSTORMS. WINDS WILL
SHIFT TO THE EAST BEHIND THE WEAK COLD FRONT.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 228 PM MDT THU JUL 18 2013
FRIDAY NIGHT ELEVATED CAPE WILL EXIST OVER THE AREA UNTIL THE
OVERNIGHT HOURS...WITH THE BEST CAPE DURING THE EVENING. THERE IS
NO CLEAR AREA OF MID/UPPER LEVEL LIFT BUT THERE IS SOME LOW LEVEL
CONVERGENCE ACROSS THE CENTRAL PART OF AREA. THE ELEVATED CAPE AND
LOW LEVEL CONVERGENCE/WEAK COLD FRONT MAY ALLOW FOR SOME STORMS TO
DEVELOP/CONTINUE...BUT CONFIDENCE AT THIS TIME IS FAIRLY LOW.
THOUGHT ABOUT TRENDING PRECIP. CHANCES ACCORDING TO WHERE THE LOW
LEVEL CONVERGENCE DEVELOPS...BUT INSTEAD KEPT THE BROAD PRECIP.
CHANCES GOING THROUGH THE EVENING. DURING THE OVERNIGHT HOURS THE
LOW LEVEL CONVERGENCE DWINDLES FROM EAST TO WEST AS THE MID LEVEL
MOISTURE AND ELEVATED CAPE DECLINE...SO HAVE PRECIP. CHANCES
TRENDING ACCORDINGLY.
SATURDAY THE LOW LEVEL CONVERGENCE RETURNS TO THE AREA AGAIN.
SOUNDINGS INDICATE THE MID LEVELS MOISTENING DURING THE AFTERNOON.
WILL AGAIN KEEP PRECIP. CHANCES KIND OF BROAD BUT KEEP THEM OVER THE
SOUTH HALF OF THE AREA WHERE THE LOW LEVEL CONVERGENCE IS BETTER.
ONE OF THE MODELS BRINGS IN A COLD POOL/COLD FRONT DURING THE
AFTERNOON FROM THE NORTH. DO NOT HAVE MUCH CONFIDENCE IN THIS
SOLUTION SINCE OTHER MODELS ARE NOT SHOWING IT.
SATURDAY EVENING AN UPPER LEVEL TROUGH AND COLD FRONT MOVE INTO THE
AREA FROM THE NORTH. THE BEST CHANCE FOR PRECIP. WILL BE DURING THE
EVENING OVER ROUGHLY THE EASTERN HALF OF THE AREA WHERE THE BEST
UPPER LEVEL LIFT WILL TRACK ACROSS. OVERNIGHT PRECIP. CHANCES COME
TO AN END AS DRIER AIR MOVES IN BEHIND THE UPPER LEVEL TROUGH.
THE MAIN THREAT FROM ANY STORMS WILL BE HEAVY RAINFALL FRIDAY
EVENING DUE TO MEAN STORM MOTIONS OF 5 TO 10 KTS AND 0-6KM SHEAR OF
10 TO 15KTS. SATURDAY THE 0-6KM SHEAR INCREASES TO 30KTS WHICH WILL
BE MORE FAVORABLE FOR SEVERE THUNDERSTORMS.
SUNDAY THROUGH THURSDAY A COUPLE WEAK COLD FRONTS/SURFACE TROUGHS
ACCOMPANIED BY AN UPPER LEVEL SHORT WAVE TROUGH MOVE ACROSS THE AREA
EARLY IN THE WEEK...BRINGING PRECIP CHANCES TO THE AREA. MID WEEK A
SURFACE TROUGH DEVELOPS OVER THE SOUTHWEST PART OF THE AREA AND
PUSHES NORTH THURSDAY BRINGING ANOTHER ROUND OF PRECIP. CHANCES FOR
THE AREA. HIGH TEMPERATURES FOR THE PERIOD WILL WARM TO ABOVE NORMAL
BY THE START OF THE WORK WEEK THEN COOL DOWN TO NEAR NORMAL BY MID
WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1105 PM MDT THU JUL 18 2013
SURFACE TROUGH WILL MOVE EAST THROUGH EASTERN COLORADO...AND WILL
REACH KGLD AROUND 09Z. THIS WILL SWITCH THE SURFACE WINDS TO THE
WEST. EXPECT WIND SHIFT AT KMCK AROUND 12Z. VFR CONDITIONS WILL
CONTINUE THROUGH THE PERIOD...BUT EXPECT CONVECTION TO DEVELOP
AFTER 18Z. THERE WILL BE CHANCE OF THUNDERSTORMS AT BOTH
KGLD/KMCK...BUT CONFIDENCE IS NOT HIGH ENOUGH TO INDICATE STORMS
IN THE TAFS. IF STORMS DO MOVE OVER THE SITES...VISIBILITIES WILL
DROP TO MVFR OR LOWER IN BRIEF HEAVY RAIN.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...MENTZER
SHORT TERM...RRH
LONG TERM...JTL
AVIATION...MENTZER
AREA FORECAST DISCUSSION
NWS JACKSON KY
1028 PM EDT SAT JUL 20 2013
.UPDATE...
ISSUED AT 1025 PM EDT SAT JUL 20 2013
MOST SHOWERS AND THUNDERSTORMS HAVE DIMINISHED TO OUR NORTH AND EAST.
HOWEVER...A LARGE LINE OF WEAK CONVECTION HAS DEVELOPED TO OUR WEST
AND CONTINUES TO SLOWLY MAKE ITS WAY EASTWARD. EXPECT SOME CONTIUED
WEAKENING BY THE TIME IT REACHES EASTERN KY...THOUGH LOW END
CHANCES/SCT COVERAGE IS STILL WARRANTED BASED ON LATEST MODEL RUNS.
UPDATED POPS TO REFLECT THIS LATEST RADAR TREND...WITH SCT CHANCES
MOVING IN ACROSS THE WESTERN CWA IN THE NEXT COUPLE OF HOURS...AND
THEN SPREADING ACROSS THE REMAINING CWA BY LATE TONIGHT.
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 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 744 PM EDT SAT JUL 20 2013
A WEAK COLD FRONT WILL PUSH SOUTHEAST AND STALL OVER NORTHERN KENTUCKY
OVERNIGHT. A COMPLEX OF SHOWERS AND STORMS CONTINUES TO OUR
NORTH AHEAD OF THIS LINE...CURRENTLY OVER SOUTHERN INDIANA AND
OHIO...BUT RADAR TRENDS ARE NOT SHOWING MUCH PROMISE FOR THIS COMPLEX
TO MOVE FAR ENOUGH SOUTH IN WHICH STORMS WILL AFFECT ANY TAF SITES
DURING THE NIGHT. IF ANYTHING DOES DEVELOP IT SHOULD BE ISOLATED...WITH
CONFIDENCE BEING TOO LOW TO INCLUDE IN TAFS AT THIS TIME. BY TOMORROW
MORNING...HOWEVER...FRONT WILL MOVE SLIGHTLY SOUTHWARD. THIS WILL BE
THE PUSH NEEDED TO BRING SCT TO NUMEROUS SHOWERS AND THUNDERSTORMS TO
THE AREA AND TAF SITES...WITH BEST COVERAGE DURING THE LATE
MORNING/MID AFTERNOON HOURS. FRONT WILL THEN BOUNCE BACK
NORTHWARD...BRINGING AN END TO BEST COVERAGE BY LATE AFTERNOON.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JMW
SHORT TERM...KAS
LONG TERM...GREIF
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS JACKSON KY
744 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 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 744 PM EDT SAT JUL 20 2013
A WEAK COLD FRONT WILL PUSH SOUTHEAST AND STALL OVER NORTHERN KENTUCKY
OVERNIGHT. A COMPLEX OF SHOWERS AND STORMS CONTINUES TO OUR
NORTH AHEAD OF THIS LINE...CURRENTLY OVER SOUTHERN INDIANA AND
OHIO...BUT RADAR TRENDS ARE NOT SHOWING MUCH PROMISE FOR THIS COMPLEX
TO MOVE FAR ENOUGH SOUTH IN WHICH STORMS WILL AFFECT ANY TAF SITES
DURING THE NIGHT. IF ANYTHING DOES DEVELOP IT SHOULD BE ISOLATED...WITH
CONFIDENCE BEING TOO LOW TO INCLUDE IN TAFS AT THIS TIME. BY TOMORROW
MORNING...HOWEVER...FRONT WILL MOVE SLIGHTLY SOUTHWARD. THIS WILL BE
THE PUSH NEEDED TO BRING SCT TO NUMEROUS SHOWERS AND THUNDERSTORMS TO
THE AREA AND TAF SITES...WITH BEST COVERAGE DURING THE LATE
MORNING/MID AFTERNOON HOURS. FRONT WILL THEN BOUNCE BACK
NORTHWARD...BRINGING AN END TO BEST COVERAGE BY LATE AFTERNOON.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JMW
SHORT TERM...KAS
LONG TERM...GREIF
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS PADUCAH KY
630 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 630 PM CDT SAT JUL 20 2013
CONVECTIVE COMPLEXES DEVELOPED THIS AFTERNOON ACROSS SOUTHERN IN/SRN
ILLINOIS/SE MISSOURI. THE LEADING EDGE OF THE OUTFLOW WINDS FROM
THIS ACTIVITY PASSED ACROSS KEVV/KCGI TAF SITES...AND WILL BE
CROSSING KOWB/KPAH VERY SOON. SOME BRIEF CIG AND VSBY RESTRICTIONS
ARE LIKELY IN THE STORMS...MAINLY AT KEVV/KOWB EARLY THIS EVENING.
HOWEVER...THE ACTIVITY APPEARS TO BE STARTING TO WEAKEN
ALREADY...AND THIS TREND WILL CONTINUE THIS EVENING.
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
223 PM EDT FRI JUL 19 2013
.UPDATE...
ISSUED AT 223 PM EDT FRI JUL 19 2013
SCATTERED SHOWERS AND THUNDERSTORMS HAVE DEVELOPED...WITH THE
GREATEST CONCENTRATION OVER THE SW PART OF THE AREA...MOVING ENE.
BASED ON RADAR TRENDS...HAVE RAISED AFTERNOON POPS SLIGHTLY...BUT
STILL IN THE CHANCE CATEGORY.
UPDATE ISSUED AT 945 AM EDT FRI JUL 19 2013
FOG PERSISTED IN THE UPPER REACHES OF THE CUMBERLAND VALLEY AT MID
MORNING...BUT HAD DISSIPATED ELSEWHERE...AND SHOULD SOON BE GONE
EVERYWHERE. OUTSIDE OF FOG...SKIES WERE GENERALLY CLEAR AT MID
MORNING. HAVE DELAYED THE INCREASE IN CLOUD COVER AND PRECIP TODAY...
WITH WIDESPREAD CU DEVELOPMENT EXPECTED AROUND MID DAY...AND
SCATTERED SHOWERS AND THUNDERSTORMS TO SOON FOLLOW.
UPDATE ISSUED AT 745 AM EDT FRI JUL 19 2013
FOG CONTINUES TO LIFT UP TO THE RIDGE TOP LEVEL IN SOUTHEASTERN KY.
K22... JKL AND I35 ARE CURRENTLY EXPERIENCING DENSE FOG. THIS SHOULD
LIFT AND DISSIPATE BY AROUND 9 AM. THE HWO...ZFP AND GRIDS ALREADY
HAD A HANDLE ON THIS. HOURLY TEMPS AND DEW POINTS WERE FRESHENED UP
BASED ON RECENT OBS. OVERALL...THE FORECAST REMAINS ON TRACK. THE 6Z
NAM AND MOST RECENT HRRR RUN APPEAR TO DEVELOP CONVECTION TOO QUICKLY
AND BOTH HAVE CONVECTION NEAR THE OH RIVER THAT IS NOT OCCURRING.
HOWEVER...DIURNALLY DRIVEN SCATTERED SHOWERS AND THUNDERSTORMS ARE
STILL ANTICIPATED...AFTER 16Z.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 325 AM EDT FRI JUL 19 2013
EARLY THIS MORNING...A RIDGE OF HIGH PRESSURE WAS LOCATED OVER THE
WESTERN CONUS WITH ANOTHER RIDGE CENTERED OVER VA WITH A BIT OF A
WEAKNESS IN BETWEEN. MEANWHILE A CLOSED UPPER LEVEL LOW WAS OVER THE
HUDSON BAY REGION IN CENTRAL CANADA. A SERIES OF UPPER LEVEL
DISTURBANCES WERE MOVING THROUGH THE WESTERLIES NEAR THE US/CANADIAN
BORDER. ONE SHORTWAVE IN PARTICULAR EXTENDED FROM WESTERN ONTARIO
DOWN INTO THE NORTHERN PLAINS/UPPER MS VALLEY REGION AND WAS
APPROACHING THE WESTERN GREAT LAKES REGION. AT THE SFC...AN AREA OF
LOW PRESSURE WAS OVER NORTHERN ONTARIO WITH A COLD FRONT EXTENDING
SOUTHWEST INTO THE UPPER MS VALLEY AND NORTHERN GREAT LAKES REGION.
LOCALLY...TEMPS ARE RATHER MILD EVEN FOR JULY WITH MOST LOCATIONS
CURRENTLY IN THE LOW TO MID 70S. PATCHY DENSE FOG HAS ALSO FORMED
MAINLY IN THE VALLEYS.
THROUGH AN HOUR OR TWO PAST DAWN...PATCHY DENSE RIVER VALLEY FOG
SHOULD GRADUALLY LIFT AND DISSIPATE. THIS WILL CONTINUE TO BE
INCLUDED IN THE HWO AND A PRE-FIRST PERIOD WILL PROBABLY BE USED TO
COVER THIS AS WELL.
THROUGH THE PERIOD...THE UPPER LEVEL LOW AND LEAD SHORTWAVE WILL
ROTATE THROUGH THE GREAT LAKES REGION AND ONTARIO INTO QUEBEC
RESPECTIVELY AS THE UPPER LEVEL RIDGE NOW OVER VA WEAKENS AND SHIFTS
OFF THE SOUTHEASTERN US COAST AND INTO THE ATLANTIC WITH RIDGING
REMAINING OVER THE WESTERN CONUS. THIS COMBINATION WILL LEAD TO A
BROAD TROUGH BEING CARVED OUT OVER MUCH OF EASTERN CANADA SOUTH INTO
MUCH OF THE EASTERN CONUS. ALTHOUGH THE ASSOCIATED COLD FRONT WILL
BECOME INCREASINGLY SHEARED WITH TIME...IT IS EXPECTED TO MOVE
THROUGH THE GREAT LAKES AND MUCH OF NEW ENGLAND BY THE END OF THE
PERIOD WITH THE TRAILING PORTION OF THE FRONT BECOMINGLY INCREASINGLY
WEST TO EAST ORIENTED AS IT APPROACHES THE OH RIVER VALLEY REGION.
THIS COLD FRONT AS SHORTWAVES MOVING THROUGH THE FLOW WILL BECOME A
FOCUS FOR CONVECTION IN THE OH VALLEY LATE IN THE PERIOD.
UNTIL THEN...THE SOURCES FOR FOCUSING CONVECTION OTHER THAN A GRADUAL
DECREASE IN HEIGHTS AND ANY LEFTOVER BOUNDARIES FROM CONVECTION IN
FRI AS WELL AS DAYTIME HEATING ARE HARD TO DETERMINE. WITH MINIMAL
SHEAR AND MODERATE INSTABILITY EXPECTED TODAY...CONVECTION SHOULD BE
SCATTERED IN NATURE. A DECREASE IN CONVECTION IS EXPECTED TONIGHT
WITH LOSS OF DAYTIME HEATING.
TEMPERATURES TODAY WILL BE LARGELY DETERMINED BY TIMING OF DEVELOPMENT
OF CU AND ANY SHRA OR TSRA. THE MAV MOS IS LIKELY TOO WARM AS IT WAS
YESTERDAY BUT THE COOLER MET NUMBERS ARE PROBABLY DUE TO ITS
CONVECTION EARLIER IN THE DAY WHICH SEEMS A BIT SUSPECT. OVERALL..A
COMPROMISE OF THE INHERITED FORECAST AND A BLEND OF THE MODEL
GUIDANCE WAS USED FOR DAYTIME HEIGHT`S TODAY. DEW POINTS ARE EXPECTED TO
REMAIN IN THE LOWER 70S AND THIS WILL LEAD TO HEAT INDEX VALUES IN
THE MID TO UPPER 90S IN THE LOWER ELEVATIONS BELOW 2000 FEET AND
POSSIBLY TOUCHING 100 IN A FEW SPOTS THIS AFTERNOON. THIS HAS ALREADY
BEEN ADDED TO AN HWO UPDATE OVERNIGHT AND WE WILL CONSIDER AN SPS FOR
THIS AS WELL.
THE APPROACHING FROM AND SHORTWAVE TROUGH SHOULD LEAD TO THE GREATEST
COVERAGE OF CONVECTION ON SATURDAY IN THE NORTH WITH MORE SCATTERED
CONVECTION FURTHER SOUTH. GREATER CLOUD COVER SHOULD LEAD TO TEMPS ON
SAT A BIT BELOW THOSE LATER TODAY.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 310 AM EDT FRI JUL 19 2013
THE EXTENDED WILL FEATURE A LARGE SCALE EASTERN CONUS TROUGH AND A
SLOW MOVING FRONTAL BOUNDARY THAT IS PROGGED TO MEANDER ABOUT THE
AREA JUST SOUTH OF THE OHIO RIVER. THE DAYTIME PERIODS WILL BE THE
MOST ACTIVE...AS PULSES OF ENERGY MOVE FROM WEST TO EAST ALONG THE
NEARLY STATIONARY BOUNDARY DURING THE AFTERNOON AND EVENING PEAK
HEATING HOURS. SHOWERS AND THUNDERSTORMS WILL BE WIDESPREAD AND
COULD BRING LOCALLY HEAVY RAINFALL TO SOME LOCATIONS...PARTICULARLY
SUNDAY THROUGH TUESDAY. THE TROUGH WILL FINALLY PUSH EASTWARD AND
OUT OF THE REGION BY THE END OF THE WEEK...AS THE UPPER PARENT
TROUGH IS DISPLACED BY A LARGE AREA OF CANADIAN HIGH PRESSURE
MIDWEEK ONWARD. TEMPERATURES SUNDAY THROUGH WEDNESDAY WILL LIKELY
RUN A BIT BELOW NORMAL...WITH WIDESPREAD CLOUD COVER AND
PRECIPITATION EXPECTED TO AFFECT THE AREA. THE END OF THE NEW WORK
WEEK WILL SEE A WARM UP TO MORE NORMAL SUMMERTIME TEMPERATURES...AS
A RIDGE OF HIGH PRESSURE BECOMES REESTABLISHED ACROSS THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 141 PM EDT FRI JUL 19 2013
THE CYCLE CONTINUES...WITH SCATTERED SHOWERS AND THUNDERSTORMS
DEVELOPING AGAIN THIS AFTERNOON. LOCALIZED IFR CAN BE EXPECTED IN
THUNDERSTORMS AND THE HEAVIER SHOWERS. MOST OF THE PRECIP SHOULD THEN
DIE OUT THIS EVENING. FOG IS FORECAST OVERNIGHT...MAINLY IN VALLEYS.
THE EXTENT OF THE FOG TONIGHT WILL BE AFFECTED BY THE EXTENT OF RAIN
THIS AFTERNOON...WITH AREAS WHICH RECEIVE RAIN LATE IN THE DAY
EXPECTED TO HAVE MORE FOG. LOCALIZED IFR WILL OCCUR IN THE FOG. FOG
WILL DISSIPATE BY AROUND MID MORNING ON SATURDAY...WITH SCATTERED
SHOWERS AND THUNDERSTORMS THEN STARTING TO POP UP AGAIN TOWARD THE
END OF THE PERIOD. OUTSIDE OF PRECIP AND FOG...MAINLY VFR SHOULD
OCCUR.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...JP
LONG TERM...AR
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS JACKSON KY
141 PM EDT FRI JUL 19 2013
.UPDATE...
ISSUED AT 945 AM EDT FRI JUL 19 2013
FOG PERSISTED IN THE UPPER REACHES OF THE CUMBERLAND VALLEY AT MID
MORNING...BUT HAD DISSIPATED ELSEWHERE...AND SHOULD SOON BE GONE
EVERYWHERE. OUTSIDE OF FOG...SKIES WERE GENERALLY CLEAR AT MID
MORNING. HAVE DELAYED THE INCREASE IN CLOUD COVER AND PRECIP TODAY...
WITH WIDESPREAD CU DEVELOPMENT EXPECTED AROUND MID DAY...AND
SCATTERED SHOWERS AND THUNDERSTORMS TO SOON FOLLOW.
UPDATE ISSUED AT 745 AM EDT FRI JUL 19 2013
FOG CONTINUES TO LIFT UP TO THE RIDGE TOP LEVEL IN SOUTHEASTERN KY.
K22... JKL AND I35 ARE CURRENTLY EXPERIENCING DENSE FOG. THIS SHOULD
LIFT AND DISSIPATE BY AROUND 9 AM. THE HWO...ZFP AND GRIDS ALREADY
HAD A HANDLE ON THIS. HOURLY TEMPS AND DEW POINTS WERE FRESHENED UP
BASED ON RECENT OBS. OVERALL...THE FORECAST REMAINS ON TRACK. THE 6Z
NAM AND MOST RECENT HRRR RUN APPEAR TO DEVELOP CONVECTION TOO QUICKLY
AND BOTH HAVE CONVECTION NEAR THE OH RIVER THAT IS NOT OCCURRING.
HOWEVER...DIURNALLY DRIVEN SCATTERED SHOWERS AND THUNDERSTORMS ARE
STILL ANTICIPATED...AFTER 16Z.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 325 AM EDT FRI JUL 19 2013
EARLY THIS MORNING...A RIDGE OF HIGH PRESSURE WAS LOCATED OVER THE
WESTERN CONUS WITH ANOTHER RIDGE CENTERED OVER VA WITH A BIT OF A
WEAKNESS IN BETWEEN. MEANWHILE A CLOSED UPPER LEVEL LOW WAS OVER THE
HUDSON BAY REGION IN CENTRAL CANADA. A SERIES OF UPPER LEVEL
DISTURBANCES WERE MOVING THROUGH THE WESTERLIES NEAR THE US/CANADIAN
BORDER. ONE SHORTWAVE IN PARTICULAR EXTENDED FROM WESTERN ONTARIO
DOWN INTO THE NORTHERN PLAINS/UPPER MS VALLEY REGION AND WAS
APPROACHING THE WESTERN GREAT LAKES REGION. AT THE SFC...AN AREA OF
LOW PRESSURE WAS OVER NORTHERN ONTARIO WITH A COLD FRONT EXTENDING
SOUTHWEST INTO THE UPPER MS VALLEY AND NORTHERN GREAT LAKES REGION.
LOCALLY...TEMPS ARE RATHER MILD EVEN FOR JULY WITH MOST LOCATIONS
CURRENTLY IN THE LOW TO MID 70S. PATCHY DENSE FOG HAS ALSO FORMED
MAINLY IN THE VALLEYS.
THROUGH AN HOUR OR TWO PAST DAWN...PATCHY DENSE RIVER VALLEY FOG
SHOULD GRADUALLY LIFT AND DISSIPATE. THIS WILL CONTINUE TO BE
INCLUDED IN THE HWO AND A PRE-FIRST PERIOD WILL PROBABLY BE USED TO
COVER THIS AS WELL.
THROUGH THE PERIOD...THE UPPER LEVEL LOW AND LEAD SHORTWAVE WILL
ROTATE THROUGH THE GREAT LAKES REGION AND ONTARIO INTO QUEBEC
RESPECTIVELY AS THE UPPER LEVEL RIDGE NOW OVER VA WEAKENS AND SHIFTS
OFF THE SOUTHEASTERN US COAST AND INTO THE ATLANTIC WITH RIDGING
REMAINING OVER THE WESTERN CONUS. THIS COMBINATION WILL LEAD TO A
BROAD TROUGH BEING CARVED OUT OVER MUCH OF EASTERN CANADA SOUTH INTO
MUCH OF THE EASTERN CONUS. ALTHOUGH THE ASSOCIATED COLD FRONT WILL
BECOME INCREASINGLY SHEARED WITH TIME...IT IS EXPECTED TO MOVE
THROUGH THE GREAT LAKES AND MUCH OF NEW ENGLAND BY THE END OF THE
PERIOD WITH THE TRAILING PORTION OF THE FRONT BECOMINGLY INCREASINGLY
WEST TO EAST ORIENTED AS IT APPROACHES THE OH RIVER VALLEY REGION.
THIS COLD FRONT AS SHORTWAVES MOVING THROUGH THE FLOW WILL BECOME A
FOCUS FOR CONVECTION IN THE OH VALLEY LATE IN THE PERIOD.
UNTIL THEN...THE SOURCES FOR FOCUSING CONVECTION OTHER THAN A GRADUAL
DECREASE IN HEIGHTS AND ANY LEFTOVER BOUNDARIES FROM CONVECTION IN
FRI AS WELL AS DAYTIME HEATING ARE HARD TO DETERMINE. WITH MINIMAL
SHEAR AND MODERATE INSTABILITY EXPECTED TODAY...CONVECTION SHOULD BE
SCATTERED IN NATURE. A DECREASE IN CONVECTION IS EXPECTED TONIGHT
WITH LOSS OF DAYTIME HEATING.
TEMPERATURES TODAY WILL BE LARGELY DETERMINED BY TIMING OF DEVELOPMENT
OF CU AND ANY SHRA OR TSRA. THE MAV MOS IS LIKELY TOO WARM AS IT WAS
YESTERDAY BUT THE COOLER MET NUMBERS ARE PROBABLY DUE TO ITS
CONVECTION EARLIER IN THE DAY WHICH SEEMS A BIT SUSPECT. OVERALL..A
COMPROMISE OF THE INHERITED FORECAST AND A BLEND OF THE MODEL
GUIDANCE WAS USED FOR DAYTIME HEIGHT`S TODAY. DEW POINTS ARE EXPECTED TO
REMAIN IN THE LOWER 70S AND THIS WILL LEAD TO HEAT INDEX VALUES IN
THE MID TO UPPER 90S IN THE LOWER ELEVATIONS BELOW 2000 FEET AND
POSSIBLY TOUCHING 100 IN A FEW SPOTS THIS AFTERNOON. THIS HAS ALREADY
BEEN ADDED TO AN HWO UPDATE OVERNIGHT AND WE WILL CONSIDER AN SPS FOR
THIS AS WELL.
THE APPROACHING FROM AND SHORTWAVE TROUGH SHOULD LEAD TO THE GREATEST
COVERAGE OF CONVECTION ON SATURDAY IN THE NORTH WITH MORE SCATTERED
CONVECTION FURTHER SOUTH. GREATER CLOUD COVER SHOULD LEAD TO TEMPS ON
SAT A BIT BELOW THOSE LATER TODAY.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 310 AM EDT FRI JUL 19 2013
THE EXTENDED WILL FEATURE A LARGE SCALE EASTERN CONUS TROUGH AND A
SLOW MOVING FRONTAL BOUNDARY THAT IS PROGGED TO MEANDER ABOUT THE
AREA JUST SOUTH OF THE OHIO RIVER. THE DAYTIME PERIODS WILL BE THE
MOST ACTIVE...AS PULSES OF ENERGY MOVE FROM WEST TO EAST ALONG THE
NEARLY STATIONARY BOUNDARY DURING THE AFTERNOON AND EVENING PEAK
HEATING HOURS. SHOWERS AND THUNDERSTORMS WILL BE WIDESPREAD AND
COULD BRING LOCALLY HEAVY RAINFALL TO SOME LOCATIONS...PARTICULARLY
SUNDAY THROUGH TUESDAY. THE TROUGH WILL FINALLY PUSH EASTWARD AND
OUT OF THE REGION BY THE END OF THE WEEK...AS THE UPPER PARENT
TROUGH IS DISPLACED BY A LARGE AREA OF CANADIAN HIGH PRESSURE
MIDWEEK ONWARD. TEMPERATURES SUNDAY THROUGH WEDNESDAY WILL LIKELY
RUN A BIT BELOW NORMAL...WITH WIDESPREAD CLOUD COVER AND
PRECIPITATION EXPECTED TO AFFECT THE AREA. THE END OF THE NEW WORK
WEEK WILL SEE A WARM UP TO MORE NORMAL SUMMERTIME TEMPERATURES...AS
A RIDGE OF HIGH PRESSURE BECOMES REESTABLISHED ACROSS THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 141 PM EDT FRI JUL 19 2013
THE CYCLE CONTINUES...WITH SCATTERED SHOWERS AND THUNDERSTORMS
DEVELOPING AGAIN THIS AFTERNOON. LOCALIZED IFR CAN BE EXPECTED IN
THUNDERSTORMS AND THE HEAVIER SHOWERS. MOST OF THE PRECIP SHOULD THEN
DIE OUT THIS EVENING. FOG IS FORECAST OVERNIGHT...MAINLY IN VALLEYS.
THE EXTENT OF THE FOG TONIGHT WILL BE AFFECTED BY THE EXTENT OF RAIN
THIS AFTERNOON...WITH AREAS WHICH RECEIVE RAIN LATE IN THE DAY
EXPECTED TO HAVE MORE FOG. LOCALIZED IFR WILL OCCUR IN THE FOG. FOG
WILL DISSIPATE BY AROUND MID MORNING ON SATURDAY...WITH SCATTERED
SHOWERS AND THUNDERSTORMS THEN STARTING TO POP UP AGAIN TOWARD THE
END OF THE PERIOD. OUTSIDE OF PRECIP AND FOG...MAINLY VFR SHOULD
OCCUR.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...JP
LONG TERM...AR
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS JACKSON KY
945 AM EDT FRI JUL 19 2013
.UPDATE...
ISSUED AT 945 AM EDT FRI JUL 19 2013
FOG PERSISTED IN THE UPPER REACHES OF THE CUMBERLAND VALLEY AT MID
MORNING...BUT HAD DISSIPATED ELSEWHERE...AND SHOULD SOON BE GONE
EVERYWHERE. OUTSIDE OF FOG...SKIES WERE GENERALLY CLEAR AT MID
MORNING. HAVE DELAYED THE INCREASE IN CLOUD COVER AND PRECIP TODAY...
WITH WIDESPREAD CU DEVELOPMENT EXPECTED AROUND MID DAY...AND
SCATTERED SHOWERS AND THUNDERSTORMS TO SOON FOLLOW.
UPDATE ISSUED AT 745 AM EDT FRI JUL 19 2013
FOG CONTINUES TO LIFT UP TO THE RIDGETOP LEVEL IN SOUTHEASTERN KY.
K22... JKL AND I35 ARE CURRENTLY EXPERIENCING DENSE FOG. THIS SHOULD
LIFT AND DISSIPATE BY AROUND 9 AM. THE HWO...ZFP AND GRIDS ALREADY
HAD A HANDLE ON THIS. HOURLY TEMPS AND DEW POINTS WERE FRESHENED UP
BASED ON RECENT OBS. OVERALL...THE FORECAST REMAINS ON TRACK. THE 6Z
NAM AND MOST RECENT HRRR RUN APPEAR TO DEVELOP CONVECTION TOO QUICKLY
AND BOTH HAVE CONVECTION NEAR THE OH RIVER THAT IS NOT OCCURRING.
HOWEVER...DIURNALLY DRIVEN SCATTERED SHOWERS AND THUNDERSTORMS ARE
STILL ANTICIPATED...AFTER 16Z.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 325 AM EDT FRI JUL 19 2013
EARLY THIS MORNING...A RIDGE OF HIGH PRESSURE WAS LOCATED OVER THE
WESTERN CONUS WITH ANOTHER RIDGE CENTERED OVER VA WITH A BIT OF A
WEAKNESS IN BETWEEN. MEANWHILE A CLOSED UPPER LEVEL LOW WAS OVER THE
HUDSON BAY REGION IN CENTRAL CANADA. A SERIES OF UPPER LEVEL
DISTURBANCES WERE MOVING THROUGH THE WESTERLIES NEAR THE US/CANADIAN
BORDER. ONE SHORTWAVE IN PARTICULAR EXTENDED FROM WESTERN ONTARIO
DOWN INTO THE NORTHERN PLAINS/UPPER MS VALLEY REGION AND WAS
APPROACHING THE WESTERN GREAT LAKES REGION. AT THE SFC...AN AREA OF
LOW PRESSURE WAS OVER NORTHERN ONTARIO WITH A COLD FRONT EXTENDING
SOUTHWEST INTO THE UPPER MS VALLEY AND NORTHERN GREAT LAKES REGION.
LOCALLY...TEMPS ARE RATHER MILD EVEN FOR JULY WITH MOST LOCATIONS
CURRENTLY IN THE LOW TO MID 70S. PATCHY DENSE FOG HAS ALSO FORMED
MAINLY IN THE VALLEYS.
THROUGH AN HOUR OR TWO PAST DAWN...PATCHY DENSE RIVER VALLEY FOG
SHOULD GRADUALLY LIFT AND DISSIPATE. THIS WILL CONTINUE TO BE
INCLUDED IN THE HWO AND A PRE-FIRST PERIOD WILL PROBABLY BE USED TO
COVER THIS AS WELL.
THROUGH THE PERIOD...THE UPPER LEVEL LOW AND LEAD SHORTWAVE WILL
ROTATE THROUGH THE GREAT LAKES REGION AND ONTARIO INTO QUEBEC
RESPECTIVELY AS THE UPPER LEVEL RIDGE NOW OVER VA WEAKENS AND SHIFTS
OFF THE SOUTHEASTERN US COAST AND INTO THE ATLANTIC WITH RIDGING
REMAINING OVER THE WESTERN CONUS. THIS COMBINATION WILL LEAD TO A
BROAD TROUGH BEING CARVED OUT OVER MUCH OF EASTERN CANADA SOUTH INTO
MUCH OF THE EASTERN CONUS. ALTHOUGH THE ASSOCIATED COLD FRONT WILL
BECOME INCREASINGLY SHEARED WITH TIME...IT IS EXPECTED TO MOVE
THROUGH THE GREAT LAKES AND MUCH OF NEW ENGLAND BY THE END OF THE
PERIOD WITH THE TRAILING PORTION OF THE FRONT BECOMINGLY INCREASINGLY
WEST TO EAST ORIENTED AS IT APPROACHES THE OH RIVER VALLEY REGION.
THIS COLD FRONT AS SHORTWAVES MOVING THROUGH THE FLOW WILL BECOME A
FOCUS FOR CONVECTION IN THE OH VALLEY LATE IN THE PERIOD.
UNTIL THEN...THE SOURCES FOR FOCUSING CONVECTION OTHER THAN A GRADUAL
DECREASE IN HEIGHTS AND ANY LEFTOVER BOUNDARIES FROM CONVECTION IN
FRI AS WELL AS DAYTIME HEATING ARE HARD TO DETERMINE. WITH MINIMAL
SHEAR AND MODERATE INSTABILITY EXPECTED TODAY...CONVECTION SHOULD BE
SCATTERED IN NATURE. A DECREASE IN CONVECTION IS EXPECTED TONIGHT
WITH LOSS OF DAYTIME HEATING.
TEMPERATURES TODAY WILL BE LARGELY DETERMINED BY TIMING OF DEVELOPMENT
OF CU AND ANY SHRA OR TSRA. THE MAV MOS IS LIKELY TOO WARM AS IT WAS
YESTERDAY BUT THE COOLER MET NUMBERS ARE PROBABLY DUE TO ITS
CONVECTION EARLIER IN THE DAY WHICH SEEMS A BIT SUSPECT. OVERALL..A
COMPROMISE OF THE INHERITED FORECAST AND A BLEND OF THE MODEL
GUIDANCE WAS USED FOR DAYTIME HEIGHT`S TODAY. DEW POINTS ARE EXPECTED TO
REMAIN IN THE LOWER 70S AND THIS WILL LEAD TO HEAT INDEX VALUES IN
THE MID TO UPPER 90S IN THE LOWER ELEVATIONS BELOW 2000 FEET AND
POSSIBLY TOUCHING 100 IN A FEW SPOTS THIS AFTERNOON. THIS HAS ALREADY
BEEN ADDED TO AN HWO UPDATE OVERNIGHT AND WE WILL CONSIDER AN SPS FOR
THIS AS WELL.
THE APPROACHING FROM AND SHORTWAVE TROUGH SHOULD LEAD TO THE GREATEST
COVERAGE OF CONVECTION ON SATURDAY IN THE NORTH WITH MORE SCATTERED
CONVECTION FURTHER SOUTH. GREATER CLOUD COVER SHOULD LEAD TO TEMPS ON
SAT A BIT BELOW THOSE LATER TODAY.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 310 AM EDT FRI JUL 19 2013
THE EXTENDED WILL FEATURE A LARGE SCALE EASTERN CONUS TROUGH AND A
SLOW MOVING FRONTAL BOUNDARY THAT IS PROGGED TO MEANDER ABOUT THE
AREA JUST SOUTH OF THE OHIO RIVER. THE DAYTIME PERIODS WILL BE THE
MOST ACTIVE...AS PULSES OF ENERGY MOVE FROM WEST TO EAST ALONG THE
NEARLY STATIONARY BOUNDARY DURING THE AFTERNOON AND EVENING PEAK
HEATING HOURS. SHOWERS AND THUNDERSTORMS WILL BE WIDESPREAD AND
COULD BRING LOCALLY HEAVY RAINFALL TO SOME LOCATIONS...PARTICULARLY
SUNDAY THROUGH TUESDAY. THE TROUGH WILL FINALLY PUSH EASTWARD AND
OUT OF THE REGION BY THE END OF THE WEEK...AS THE UPPER PARENT
TROUGH IS DISPLACED BY A LARGE AREA OF CANADIAN HIGH PRESSURE
MIDWEEK ONWARD. TEMPERATURES SUNDAY THROUGH WEDNESDAY WILL LIKELY
RUN A BIT BELOW NORMAL...WITH WIDESPREAD CLOUD COVER AND
PRECIPITATION EXPECTED TO AFFECT THE AREA. THE END OF THE NEW WORK
WEEK WILL SEE A WARM UP TO MORE NORMAL SUMMERTIME TEMPERATURES...AS
A RIDGE OF HIGH PRESSURE BECOMES REESTABLISHED ACROSS THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 750 AM EDT FRI JUL 19 2013
FOG WILL CONTINUE TO LIFT AND DISSIPATE THROUGH ABOUT 13Z. INITIALLY
FOG WILL BE BELOW AIRPORT MINS AT JKL AND IN THE IFR RANGE AT
LOZ...WITH THIS IMPROVING BY 13Z. DIURNALLY DRIVEN CONVECTION
SHOULD DEVELOP AFTER 16Z...BUT DECREASE IN COVERAGE BY THE 0Z TO 3Z
PERIOD. SOME MVFR OR LOWER FOG WILL BE POSSIBLE IN ALL AREAS FROM
ABOUT 6Z ON ONCE AGAIN...ESPECIALLY WHERE CONVECTION OCCURS LATER
TODAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...JP
LONG TERM...AR
AVIATION...JP
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
750 AM EDT FRI JUL 19 2013
.UPDATE...
ISSUED AT 745 AM EDT FRI JUL 19 2013
FOG CONTINUES TO LIFT UP TO THE RIDGETOP LEVEL IN SOUTHEASTERN KY.
K22... JKL AND I35 ARE CURRENTLY EXPERIENCING DENSE FOG. THIS SHOULD
LIFT AND DISSIPATE BY AROUND 9 AM. THE HWO...ZFP AND GRIDS ALREADY
HAD A HANDLE ON THIS. HOURLY TEMPS AND DEWPOINTS WERE FRESHENED UP
BASED ON RECENT OBS. OVERALL...THE FORECAST REMAINS ON TRACK. THE 6Z
NAM AND MOST RECENT HRRR RUN APPEAR TO DEVELOP CONVECTION TOO QUICKLY
AND BOTH HAVE CONVECTION NEAR THE OH RIVER THAT IS NOT OCCURRING.
HOWEVER...DIURNALLY DRIVEN SCATTERED SHOWERS AND THUNDERSTORMS ARE
STILL ANTICIPATED...AFTER 16Z.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 325 AM EDT FRI JUL 19 2013
EARLY THIS MORNING...A RIDGE OF HIGH PRESSURE WAS LOCATED OVER THE
WESTERN CONUS WITH ANOTHER RIDGE CENTERED OVER VA WITH A BIT OF A
WEAKNESS IN BETWEEN. MEANWHILE A CLOSED UPPER LEVEL LOW WAS OVER THE
HUDSON BAY REGION IN CENTRAL CANADA. A SERIES OF UPPER LEVEL
DISTURBANCES WERE MOVING THROUGH THE WESTERLIES NEAR THE US/CANADIAN
BORDER. ONE SHORTWAVE IN PARTICULAR EXTENDED FROM WESTERN ONTARIO
DOWN INTO THE NORTHERN PLAINS/UPPER MS VALLEY REGION AND WAS
APPROACHING THE WESTERN GREAT LAKES REGION. AT THE SFC...AN AREA OF
LOW PRESSURE WAS OVER NORTHERN ONTARIO WITH A COLD FRONT EXTENDING
SOUTHWEST INTO THE UPPER MS VALLEY AND NORTHERN GREAT LAKES REGION.
LOCALLY...TEMPS ARE RATHER MILD EVEN FOR JULY WITH MOST LOCATIONS
CURRENTLY IN THE LOW TO MID 70S. PATCHY DENSE FOG HAS ALSO FORMED
MAINLY IN THE VALLEYS.
THROUGH AN HOUR OR TWO PAST DAWN...PATCHY DENSE RIVER VALLEY FOG
SHOULD GRADUALLY LIFT AND DISSIPATE. THIS WILL CONTINUE TO BE
INCLUDED IN THE HWO AND A PREFIRST PERIOD WILL PROBABLY BE USED TO
COVER THIS AS WELL.
THROUGH THE PERIOD...THE UPPER LEVEL LOW AND LEAD SHORTWAVE WILL
ROTATE THROUGH THE GREAT LAKES REGION AND ONTARIO INTO QUEBEC
RESPECTIVELY AS THE UPPER LEVEL RIDGE NOW OVER VA WEAKENS AND SHIFTS
OFF THE SOUTHEASTERN US COAST AND INTO THE ATLANTIC WITH RIDGING
REMAINING OVER THE WESTERN CONUS. THIS COMBINATION WILL LEAD TO A
BROAD TROUGH BEING CARVED OUT OVER MUCH OF EASTERN CANADA SOUTH INTO
MUCH OF THE EASTERN CONUS. ALTHOUGH THE ASSOCIATED COLD FRONT WILL
BECOME INCREASINGLY SHEARED WITH TIME...IT IS EXPECTED TO MOVE
THROUGH THE GREAT LAKES AND MUCH OF NEW ENGLAND BY THE END OF THE
PERIOD WITH THE TRAILING PORTION OF THE FRONT BECOMINGLY INCREASINGLY
WEST TO EAST ORIENTED AS IT APPROACHES THE OH RIVER VALLEY REGION.
THIS COLD FRONT AS SHORTWAVES MOVING THROUGH THE FLOW WILL BECOME A
FOCUS FOR CONVECTION IN THE OH VALLEY LATE IN THE PERIOD.
UNTIL THEN...THE SOURCES FOR FOCUSING CONVECTION OTHER THAN A GRADUAL
DECREASE IN HEIGHTS AND ANY LEFTOVER BOUNDARIES FROM CONVECTION IN
FRI AS WELL AS DAYTIME HEATING ARE HARD TO DETERMINE. WITH MINIMAL
SHEAR AND MODERATE INSTABILITY EXPECTED TODAY...CONVECTION SHOULD BE
SCATTERED IN NATURE. A DECREASE IN CONVECTION IS EXPECTED TONIGHT
WITH LOSS OF DAYTIME HEATING.
TEMPERATURES TODAY WILL BE LARGELY DETERMINED BY TIMING OF DEVELOPMENT
OF CU AND ANY SHRA OR TSRA. THE MAV MOS IS LIKELY TOO WARM AS IT WAS
YESTERDAY BUT THE COOLER MET NUMBERS ARE PROBABLY DUE TO ITS
CONVECTION EARLIER IN THE DAY WHICH SEEMS A BIT SUSPECT. OVERALL..A
COMPROMISE OF THE INHERITED FORECAST AND A BLEND OF THE MODEL
GUIDANCE WAS USED FOR DAYTIME HEIGHT`S TODAY. DEWPOINTS ARE EXPECTED TO
REMAIN IN THE LOWER 70S AND THIS WILL LEAD TO HEAT INDEX VALUES IN
THE MID TO UPPER 90S IN THE LOWER ELEVATIONS BELOW 2000 FEET AND
POSSIBLY TOUCHING 100 IN A FEW SPOTS THIS AFTERNOON. THIS HAS ALREADY
BEEN ADDED TO AN HWO UPDATE OVERNIGHT AND WE WILL CONSIDER AN SPS FOR
THIS AS WELL.
THE APPROACHING FROM AND SHORTWAVE TROUGH SHOULD LEAD TO THE GREATEST
COVERAGE OF CONVECTION ON SATURDAY IN THE NORTH WITH MORE SCATTERED
CONVECTION FURTHER SOUTH. GREATER CLOUD COVER SHOULD LEAD TO TEMPS ON
SAT A BIT BELOW THOSE LATER TODAY.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 310 AM EDT FRI JUL 19 2013
THE EXTENDED WILL FEATURE A LARGE SCALE EASTERN CONUS TROUGH AND A
SLOW MOVING FRONTAL BOUNDARY THAT IS PROGGED TO MEANDER ABOUT THE
AREA JUST SOUTH OF THE OHIO RIVER. THE DAYTIME PERIODS WILL BE THE
MOST ACTIVE...AS PULSES OF ENERGY MOVE FROM WEST TO EAST ALONG THE
NEARLY STATIONARY BOUNDARY DURING THE AFTERNOON AND EVENING PEAK
HEATING HOURS. SHOWERS AND THUNDERSTORMS WILL BE WIDESPREAD AND
COULD BRING LOCALLY HEAVY RAINFALL TO SOME LOCATIONS...PARTICULARLY
SUNDAY THROUGH TUESDAY. THE TROUGH WILL FINALLY PUSH EASTWARD AND
OUT OF THE REGION BY THE END OF THE WEEK...AS THE UPPER PARENT
TROUGH IS DISPLACED BY A LARGE AREA OF CANADIAN HIGH PRESSURE
MIDWEEK ONWARD. TEMPERATURES SUNDAY THROUGH WEDNESDAY WILL LIKELY
RUN A BIT BELOW NORMAL...WITH WIDESPREAD CLOUD COVER AND
PRECIPITATION EXPECTED TO AFFECT THE AREA. THE END OF THE NEW WORK
WEEK WILL SEE A WARM UP TO MORE NORMAL SUMMERTIME TEMPERATURES...AS
A RIDGE OF HIGH PRESSURE BECOMES REESTABLISHED ACROSS THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 750 AM EDT FRI JUL 19 2013
FOG WILL CONTINUE TO LIFT AND DISSIPATE THROUGH ABOUT 13Z. INITIALLY
FOG WILL BE BELOW AIRPORT MINS AT JKL AND IN THE IFR RANGE AT
LOZ...WITH THIS IMPROVING BY 13Z. DIURNALLY DRIVEN CONVECTION
SHOULD DEVELOP AFTER 16Z...BUT DECREASE IN COVERAGE BY THE 0Z TO 3Z
PERIOD. SOME MVFR OR LOWER FOG WILL BE POSSIBLE IN ALL AREAS FROM
ABOUT 6Z ON ONCE AGAIN...ESPECIALLY WHERE CONVECTION OCCURS LATER
TODAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...JP
LONG TERM...AR
AVIATION...JP
AREA FORECAST DISCUSSION
NWS CARIBOU ME
928 PM EDT SAT JUL 20 2013
.SYNOPSIS...
A STRONG COLD FRONT WILL CROSS THE REGION OVERNIGHT. A DRIER AND
COOLER CANADIAN AIR MASS 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/...
928 PM UPDATE...A COLD FRONT ENTERING THE NORTHERN PORTION OF THE
CWA WILL SWEEP ACROSS THE REMAINDER OF THE AREA TONIGHT...USHERING
A MUCH DRIER AND COOLER AIR MASS ACROSS THE REGION. THE THREAT OF
SEVERE WEATHER ENDED EARLIER THIS EVENING WITH NOTHING MORE THAN
ISOLATED SHOWERS EXPECTED DURING THE NEXT FEW HOURS. CLEARING WILL
GRADUALLY WORK INTO THE AREA IN THE WAKE OF THE COLD FRONT.
UPDATED THE WX GRIDS TO REMOVE THUNDERSTORMS FOR THE REMAINDER OF
THE EVENING AND UPLOADED THE PAST FEW HOURS OF OBSERVED DATA AND
INTERPOLATED THROUGH THE OVERNIGHT. OVERNIGHT LOWS WERE DROPPED
SEVERAL DEGREES ACROSS THE WESTERN ZONES WHERE TEMPS AT 01Z WERE
RUNNING SEVERAL DEGREES ABOVE FORECAST VALUES. IT APPEARS THAT
THERE WILL BE SOME MIXING AND WIND OVERNIGHT AND WITH THE LOWERING
DEW POINTS DO NOT ANTICIPATE THAT THE RISK OF FOG IS GREAT AND
REMOVED IT FROM THE GRIDS.
UPDATE 1920 EDT: HAVE ADJUSTED POPS ...WEATHER GRIDS AND
TEMPERATURES BASED ON LATEST OBSERVATIONS.
PREVIOUS DISCUSSION...
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/...
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 /MONDAY 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 /01Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: VFR THROUGH 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 RUNNING AROUND 4 FT AT THE EASTERN MAINE SHELF
THIS EVENING. 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...CB/HEWITT/MIGNONE
SHORT TERM...BLOOMER
LONG TERM...BLOOMER
AVIATION...CB/HEWITT/MIGNONE/BLOOMER
MARINE...CB/HEWITT/MIGNONE/BLOOMER
AREA FORECAST DISCUSSION
NWS CARIBOU ME
723 PM EDT SAT JUL 20 2013
.SYNOPSIS...
A STRONG COLD FRONT WILL CROSS THE REGION OVERNIGHT. 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/...
UPDATE 1920 EDT: HAVE ADJUSTED POPS ...WEATHER GRIDS AND
TEMPERATURES BASED ON LATEST OBSERVATIONS.
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/...
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 /MONDAY 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 /00Z SUNDAY THROUGH THURSDAY/...
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...MIGNONE
AREA FORECAST DISCUSSION
NWS GRAY ME
644 PM EDT FRI JUL 19 2013
.SYNOPSIS...
HOT AND HUMID WEATHER WILL CONTINUE THIS EVENING ALONG WITH THE
POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS...ESPECIALLY ACROSS
NORTHERN AREAS WHERE A SEVERE THUNDERSTORM WATCH IS IN EFFECT
THROUGH 11 PM THIS EVENING. OTHERWISE VERY WARM AND MUGGY WEATHER
AHEAD OF AN APPROACHING COLD FRONT. THE FRONT WILL MOVE OFF THE
COAST SATURDAY NIGHT WITH ANOTHER CHANCE OF STRONG TO SEVERE
THUNDERSTORMS DURING THE DAY SATURDAY. HIGH PRESSURE FOLLOWS THE
FRONT BRINGING COOLER AND LESS HUMID AIR TO THE REGION WHICH WILL
END OUR HEAT WAVE. THE HIGH WILL HOLD ON THROUGH TUESDAY. WEAK
LOW PRESSURE WILL MOVE THROUGH SOUTHERN NEW ENGLAND TUESDAY NIGHT
AND WEDNESDAY...PROVIDING THE NEXT CHANCE OF SHOWERS OR
THUNDERSTORMS.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
WILL UPDATE TO ADJUST CHANCE OF SHOWERS AND THUNDERSTORMS BASED ON
LATEST RADAR. RADAR SHOWING LINE OF STRONG/SEVERE THUNDERSTORMS
MOVING THROUGH OUR NORTHERN MOST ZONES. A FEW SHOWERS JUST SOUTH
OF THE LINE WITH MOST OF THE FORECAST AREA DRY AT THIS TIME. THE
LINE OF STORMS WILL CONTINUE TO MOVE EAST WHILE OTHER SHOWERS AND
ISOLATED TO SCATTERED THUNDERSTORMS MAKE THERE WAY INTO THE REGION
LATER THIS EVENING.
HAVE ADDED PATCHY VALLEY FOG LATER TONIGHT DUE TO ANY RAINFALL
THAT OCCURS AND SATURATES THE BOUNDARY LAYER WHERE WE ALREADY HAVE
VERY HIGH DEW POINTS.
ALREADY UPDATED FORECAST TO ISSUE A SEVERE THUNDERSTORM WATCH FOR
OUR NORTHERN ZONES WHICH INCLUDE COOS COUNTY IN NH AND OXFORD...
FRANKLIN AND SOMERSET COUNTIES IN MAINE. THE WATCH IS IN EFFECT
THROUGH 11 PM THIS EVENING.
PREVIOUS DISCUSSION...
HOT AND HUMID CONDITIONS ACROSS THE COASTAL PLAIN WILL GIVE WAY TO
A WARM AND MUGGY NIGHT. DEW POINTS WILL ONCE AGAIN BE IN THE
70S... AND LOW TEMPERATURES WILL ONLY REACH THE LOW TO MID 70S FOR
MUCH OF THE COASTAL PLAIN. THIS WILL MAKE IT DIFFICULT FOR HOT
BUILDINGS THAT BAKED IN THE HEAT TODAY TO COOL OFF MUCH OVERNIGHT
WITHOUT THE HELP OF AIR CONDITIONING.
SHOWER AND THUNDERSTORM ACTIVITY HAS FAILED TO DEVELOP THIS
AFTERNOON OVER THE FORECAST AREA... BUT EXPECT SOME DEVELOPMENT
OVER THE HIGHER TERRAIN OF NEW YORK STATE AND SOUTHERN VERMONT.
THIS MAY MOVE INTO SOUTHERN NEW HAMPSHIRE AND SOUTHWEST MAINE THIS
EVENING. OTHER MORE WIDESPREAD SHOWERS AND STORMS HAVE FORMED A
LINE IN SOUTHEAST ONTARIO AND SOUTHERN QUEBEC... MOVING TOWARD
MONTREAL. THIS WILL LIKELY HOLD TOGETHER AND BEGIN IMPACTING FAR
NORTHERN MAINE ZONES BY 6 PM. OTHER DEVELOPMENT FURTHER WEST MAY
ALSO MOVE INTO THE NORTHERN PORTIONS OF THE FORECAST AREA AROUND 9
PM. THE HRRR MODEL IS ONCE AGAIN HANDLING THIS ACTIVITY QUITE
WELL. DAMAGING WINDS AND HEAVY RAINFALL WILL BE A THREAT WITH
THESE STORMS ESPECIALLY AS THEY FORM A LINE WITH EMBEDDED BOWING
SEGMENTS.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
EXPECT THE COLD FRONT TO BE PUSHING INTO NORTHERN AREAS BY
SATURDAY MORNING... WITH SHOWERS AND THUNDERSTORMS ALONG AND AHEAD
OF IT. MAY HAVE ACTIVITY ONGOING AT 8 AM... PROGRESSING SOUTHEAST
ACROSS THE FORECAST AREA THROUGH THE AFTERNOON. THUNDERSTORM
CHANCES DIMINISH THROUGH THE LATE AFTERNOON AS THE FRONT PUSHES
OFFSHORE. WIND SHEAR WILL BE SUPPORTIVE FOR STORM ORGANIZATION AND
A DAMAGING WIND THREAT.
HIGH TEMPERATURES WILL REACH THE UPPER 80S AND LOW 90S ALONG THE
COASTAL PLAIN WHERE SOME HEATING WILL OCCUR BEFORE THUNDERSTORMS
ARRIVE. LINGERING HUMIDITY WILL ALLOW HEAT INDEX VALUES TO REACH
THE UPPER 90S BUT SHOULD NOT REACH HEAT ADVISORY LEVELS.
WITH THE COLD FRONT PUSHING OFFSHORE AND DRY HIGH PRESSURE
BUILDING IN BEHIND IT... EXPECT A BREAK FROM THE HUMID WEATHER AND
A RETURN TO MORE SEASONABLE TEMPERATURES. LOWS WILL REACH THE 50S
AND LOW 60S.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
SUNDAY WILL FINALLY BRING AN END TO THE HEAT AND HUMIDITY...WITH
DEW POINTS DROPPING INTO 50S AND HIGHS IN THE 70S TO AROUND 80...
UNDER MAINLY SUNNY SKIES. THE HIGH SHOULD STAY IN PLACE BENEATH
MAINLY ZONAL FLOW ALOFT THROUGH TUESDAY...WITH SEASONABLE TEMPS
AND RH LEVELS.
MODELS SUGGESTING SEVERAL 500MB WAVES TRACKING OUT ACROSS THE GREAT
LAKES TUESDAY INTO THE END OF THE WEEK...CARVING OUT A LARGER SCALE
TROUGH OVER THE EASTERN THIRD OF THE CONUS. THERE WILL BE A COUPLE
CHANCES FOR PRECIP AS THESE WAVES MOVE THROUGH...THE FIRST OF WHICH
LOOKS TO BE TUESDAY NIGHT OR WEDNESDAY. AS THE 500 MB TROUGH DIGS
TO THE WEST...WILL SEE AN INCREASE IN MOISTURE...WITH MORE HUMID
CONDITIONS RETURNING MID-LATE WEEK.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM /THROUGH SATURDAY NIGHT/...SEVERE TSTM WATCH IN EFFECT
THROUGH 03Z THIS EVE FOR OUR NORTHERN ZONES WHICH IMPACTS HIE.
ISOLD TO SCT TSTMS COULD ALSO IMPACT REST OF FORECAST AREA
OVERNIGHT...RESULTING IN GUSTY WINDS AND LOWER CIG/VSBY. PATCHY F
COULD FORM OVERNIGHT ESPECIALLY WHERE RAIN FALLS...LEADING TO
LOCAL IFR/LIFR. TSTMS POSSIBLE SATURDAY WITH SEVERE WX AGAIN A
POSSIBILITY AS A COLD FRONT MOVES THROUGH LATER IN THE DAY. HIGH
PRESSURE BUILDS IN SATURDAY NIGHT BRINGING VFR WX, WITH SOME
PATCHY LATE NIGHT VALLEY F POSSIBLE, AS IT PUSHES TSTMS OUT TO
SEA.
LONG TERM...MAINLY VFR THROUGH WEDNESDAY. SOME VALLEY FOG WILL BE
POSSIBLE SUNDAY AND MONDAY NIGHT WITH RESTRICTIONS POSSIBLE IN FOG
AND COASTAL STRATUS TUESDAY NIGHT.
&&
.MARINE...
SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...WILL UPDATE TO
INCREASE WINDS/GUSTS A BIT AND LOWER SEAS SOME FOR THIS EVENING
BASED ON LATEST BUOY REPORTS. SMALL CRAFT ADVISORY CONTINUES FOR
THE OUTER WATERS. THE PERSISTENT SOUTHWEST FLOW WILL ALLOW SEAS
TO BUILD THROUGH TONIGHT... BUT MODELS TEND TO OVERDO THE WAVE
HEIGHTS ON SOUTHWEST FLOW. STILL MAY SEE SOME 5 FT SEAS IN EASTERN
AREAS BY MORNING. SEAS SHOULD SUBSIDE FROM SOUTHWEST TO NORTHEAST
DURING THE DAY ON SATURDAY. WINDS LET UP LATE SATURDAY THEN SHIFT
TO NW AS THE FRONT MOVES OFFSHORE SATURDAY NIGHT.
LONG TERM...WATERS SHOULD BE QUIET SUNDAY THROUGH WEDNESDAY...WITH
LIGHT WINDS...AND SEAS BELOW 5FT.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR MEZ012-018>021-
023-024.
NH...EXCESSIVE HEAT WARNING UNTIL 7 PM EDT THIS EVENING FOR NHZ010-
013-014.
HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR NHZ006-008-009.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR ANZ150-152.
SMALL CRAFT ADVISORY UNTIL NOON EDT SATURDAY FOR ANZ154.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
418 PM EDT FRI JUL 19 2013
.SYNOPSIS...
HOT AND HUMID WEATHER WILL CONTINUE THIS EVENING ALONG WITH THE
POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS...ESPECIALLY ACROSS
NORTHERN AREAS WHERE A SEVERE THUNDERSTORM WATCH IS IN EFFECT
THROUGH 11 PM THIS EVENING. OTHERWISE VERY WARM AND MUGGY WEATHER
AHEAD OF AN APPROACHING COLD FRONT. THE FRONT WILL MOVE OFF THE
COAST SATURDAY NIGHT WITH ANOTHER CHANCE OF STRONG TO SEVERE
THUNDERSTORMS DURING THE DAY SATURDAY. HIGH PRESSURE FOLLOWS THE
FRONT BRINGING COOLER AND LESS HUMID AIR TO THE REGION WHICH WILL
END OUR HEAT WAVE. THE HIGH WILL HOLD ON THROUGH TUESDAY. WEAK
LOW PRESSURE WILL MOVE THROUGH SOUTHERN NEW ENGLAND TUESDAY NIGHT
AND WEDNESDAY...PROVIDING THE NEXT CHANCE OF SHOWERS OR
THUNDERSTORMS.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
UPDATED FORECAST TO ISSUE A SEVERE THUNDERSTORM WATCH FOR OUR
NORTHERN ZONES WHICH INCLUDE COOS COUNTY IN NH AND OXFORD...
FRANKLIN AND SOMERSET COUNTIES IN MAINE. THE WATCH IS IN EFFECT
THROUGH 11 PM THIS EVENING.
HOT AND HUMID CONDITIONS ACROSS THE COASTAL PLAIN WILL GIVE WAY TO
A WARM AND MUGGY NIGHT. DEW POINTS WILL ONCE AGAIN BE IN THE
70S... AND LOW TEMPERATURES WILL ONLY REACH THE LOW TO MID 70S FOR
MUCH OF THE COASTAL PLAIN. THIS WILL MAKE IT DIFFICULT FOR HOT
BUILDINGS THAT BAKED IN THE HEAT TODAY TO COOL OFF MUCH OVERNIGHT
WITHOUT THE HELP OF AIR CONDITIONING.
SHOWER AND THUNDERSTORM ACTIVITY HAS FAILED TO DEVELOP THIS
AFTERNOON OVER THE FORECAST AREA... BUT EXPECT SOME DEVELOPMENT
OVER THE HIGHER TERRAIN OF NEW YORK STATE AND SOUTHERN VERMONT.
THIS MAY MOVE INTO SOUTHERN NEW HAMPSHIRE AND SOUTHWEST MAINE THIS
EVENING. OTHER MORE WIDESPREAD SHOWERS AND STORMS HAVE FORMED A
LINE IN SOUTHEAST ONTARIO AND SOUTHERN QUEBEC... MOVING TOWARD
MONTREAL. THIS WILL LIKELY HOLD TOGETHER AND BEGIN IMPACTING FAR
NORTHERN MAINE ZONES BY 6 PM. OTHER DEVELOPMENT FURTHER WEST MAY
ALSO MOVE INTO THE NORTHERN PORTIONS OF THE FORECAST AREA AROUND 9
PM. THE HRRR MODEL IS ONCE AGAIN HANDLING THIS ACTIVITY QUITE
WELL. DAMAGING WINDS AND HEAVY RAINFALL WILL BE A THREAT WITH
THESE STORMS ESPECIALLY AS THEY FORM A LINE WITH EMBEDDED BOWING
SEGMENTS.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
EXPECT THE COLD FRONT TO BE PUSHING INTO NORTHERN AREAS BY
SATURDAY MORNING... WITH SHOWERS AND THUNDERSTORMS ALONG AND AHEAD
OF IT. MAY HAVE ACTIVITY ONGOING AT 8 AM... PROGRESSING SOUTHEAST
ACROSS THE FORECAST AREA THROUGH THE AFTERNOON. THUNDERSTORM
CHANCES DIMINISH THROUGH THE LATE AFTERNOON AS THE FRONT PUSHES
OFFSHORE. WIND SHEAR WILL BE SUPPORTIVE FOR STORM ORGANIZATION AND
A DAMAGING WIND THREAT.
HIGH TEMPERATURES WILL REACH THE UPPER 80S AND LOW 90S ALONG THE
COASTAL PLAIN WHERE SOME HEATING WILL OCCUR BEFORE THUNDERSTORMS
ARRIVE. LINGERING HUMIDITY WILL ALLOW HEAT INDEX VALUES TO REACH
THE UPPER 90S BUT SHOULD NOT REACH HEAT ADVISORY LEVELS.
WITH THE COLD FRONT PUSHING OFFSHORE AND DRY HIGH PRESSURE
BUILDING IN BEHIND IT... EXPECT A BREAK FROM THE HUMID WEATHER AND
A RETURN TO MORE SEASONABLE TEMPERATURES. LOWS WILL REACH THE 50S
AND LOW 60S.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
SUNDAY WILL FINALLY BRING AN END TO THE HEAT AND HUMIDITY...WITH
DEW POINTS DROPPING INTO 50S AND HIGHS IN THE 70S TO AROUND 80...
UNDER MAINLY SUNNY SKIES. THE HIGH SHOULD STAY IN PLACE BENEATH
MAINLY ZONAL FLOW ALOFT THROUGH TUESDAY...WITH SEASONABLE TEMPS
AND RH LEVELS.
MODELS SUGGESTING SEVERAL 500MB WAVES TRACKING OUT ACROSS THE GREAT
LAKES TUESDAY INTO THE END OF THE WEEK...CARVING OUT A LARGER SCALE
TROUGH OVER THE EASTERN THIRD OF THE CONUS. THERE WILL BE A COUPLE
CHANCES FOR PRECIP AS THESE WAVES MOVE THROUGH...THE FIRST OF WHICH
LOOKS TO BE TUESDAY NIGHT OR WEDNESDAY. AS THE 500 MB TROUGH DIGS
TO THE WEST...WILL SEE AN INCREASE IN MOISTURE...WITH MORE HUMID
CONDITIONS RETURNING MID-LATE WEEK.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
SHORT TERM...GUSTY SOUTHWEST WINDS WILL SUBSIDE SOMEWHAT LATE THIS
AFTERNOON. THUNDERSTORMS ARE POSSIBLE MAINLY THIS EVENING IN
NORTHERN AREAS... THOUGH THERE COULD BE A THUNDERSTORM OR TWO OVER
SOUTHERN NEW HAMPSHIRE THIS AFTERNOON. DESPITE CONTINUED HUMID
WEATHER... DO NOT EXPECT FOG TONIGHT. FOG LAST NIGHT WAS DUE TO
INCREASING DEW POINTS OVERNIGHT... WHILE THEY SHOULD HOLD STEADY
TONIGHT WITH WINDS STAYING IN THE 5 TO 10 KNOT RANGE.
THUNDERSTORMS ARE LIKELY ON SATURDAY DURING THE DAY AS A COLD
FRONT MOVES THROUGH.
LONG TERM...MAINLY VFR THROUGH WEDNESDAY. SOME VALLEY FOG WILL BE
POSSIBLE SUNDAY AND MONDAY NIGHT WITH RESTRICTIONS POSSIBLE IN FOG
AND COASTAL STRATUS TUESDAY NIGHT.
&&
.MARINE...
SHORT TERM...SMALL CRAFT ADVISORY CONTINUES FOR THE OUTER WATERS.
ALTHOUGH 850 MB WIND SPEEDS ARE 30 TO 35 KNOTS... THE INVERSION
THAT LIKELY EXISTS OVER THE COOLER WATERS IN THIS ENVIRONMENT WILL
PREVENT WIND GUSTS FROM GETTING MUCH ABOVE 20 TO 25 KT. THE
PERSISTENT SOUTHWEST FLOW WILL ALLOW SEAS TO BUILD THROUGH
TONIGHT... BUT MODELS TEND TO OVERDO THE WAVE HEIGHTS ON SOUTHWEST
FLOW. STILL MAY SEE SOME 5 FT SEAS IN EASTERN AREAS BY MORNING.
SEAS SHOULD SUBSIDE FROM SOUTHWEST TO NORTHEAST DURING THE DAY ON
SATURDAY.
LONG TERM...WATERS SHOULD BE QUIET SUNDAY THROUGH WEDNESDAY...WITH
LIGHT WINDS...AND SEAS BELOW 5FT.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR MEZ012-018>021-
023-024.
NH...EXCESSIVE HEAT WARNING UNTIL 7 PM EDT THIS EVENING FOR NHZ010-
013-014.
HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR NHZ006-008-009.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR ANZ150-152.
SMALL CRAFT ADVISORY UNTIL NOON EDT SATURDAY FOR ANZ154.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
415 PM EDT FRI JUL 19 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION ON SATURDAY...PRODUCING
POTENTIALLY SEVERE STORMS. BEHIND THIS FRONT...COOLER AND LESS
HUMID HIGH PRESSURE WILL BUILD IN...BRINGING AN END TO OUR HEAT
WAVE. THIS HIGH HOLD FOR SUNDAY THROUGH TUESDAY...WITH HIGHS IN THE
70S TO LOW 80S...AND OVERNIGHT LOWS IN THE 50S TO AROUND 60. WEAK
LOW PRESSURE WILL MOVE THROUGH SOUTHERN NEW ENGLAND TUESDAY NIGHT
AND WEDNESDAY...PROVIDING THE NEXT CHANCE OF SHOWERS OR
THUNDERSTORMS.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
UPDATED FORECAST TO ISSUE A SEVERE THUNDERSTORM WATCH FOR OUR
NORTHERN ZONES WHICH INCLUDE COOS COUNTY IN NH AND OXFORD...
FRANKLIN AND SOMERSET COUNTIES IN MAINE. THE WATCH IS IN EFFECT
THROUGH 11 PM THIS EVENING.
HOT AND HUMID CONDITIONS ACROSS THE COASTAL PLAIN WILL GIVE WAY TO
A WARM AND MUGGY NIGHT. DEW POINTS WILL ONCE AGAIN BE IN THE
70S... AND LOW TEMPERATURES WILL ONLY REACH THE LOW TO MID 70S FOR
MUCH OF THE COASTAL PLAIN. THIS WILL MAKE IT DIFFICULT FOR HOT
BUILDINGS THAT BAKED IN THE HEAT TODAY TO COOL OFF MUCH OVERNIGHT
WITHOUT THE HELP OF AIR CONDITIONING.
SHOWER AND THUNDERSTORM ACTIVITY HAS FAILED TO DEVELOP THIS
AFTERNOON OVER THE FORECAST AREA... BUT EXPECT SOME DEVELOPMENT
OVER THE HIGHER TERRAIN OF NEW YORK STATE AND SOUTHERN VERMONT.
THIS MAY MOVE INTO SOUTHERN NEW HAMPSHIRE AND SOUTHWEST MAINE THIS
EVENING. OTHER MORE WIDESPREAD SHOWERS AND STORMS HAVE FORMED A
LINE IN SOUTHEAST ONTARIO AND SOUTHERN QUEBEC... MOVING TOWARD
MONTREAL. THIS WILL LIKELY HOLD TOGETHER AND BEGIN IMPACTING FAR
NORTHERN MAINE ZONES BY 6 PM. OTHER DEVELOPMENT FURTHER WEST MAY
ALSO MOVE INTO THE NORTHERN PORTIONS OF THE FORECAST AREA AROUND 9
PM. THE HRRR MODEL IS ONCE AGAIN HANDLING THIS ACTIVITY QUITE
WELL. DAMAGING WINDS AND HEAVY RAINFALL WILL BE A THREAT WITH
THESE STORMS ESPECIALLY AS THEY FORM A LINE WITH EMBEDDED BOWING
SEGMENTS.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
EXPECT THE COLD FRONT TO BE PUSHING INTO NORTHERN AREAS BY
SATURDAY MORNING... WITH SHOWERS AND THUNDERSTORMS ALONG AND AHEAD
OF IT. MAY HAVE ACTIVITY ONGOING AT 8 AM... PROGRESSING SOUTHEAST
ACROSS THE FORECAST AREA THROUGH THE AFTERNOON. THUNDERSTORM
CHANCES DIMINISH THROUGH THE LATE AFTERNOON AS THE FRONT PUSHES
OFFSHORE. WIND SHEAR WILL BE SUPPORTIVE FOR STORM ORGANIZATION AND
A DAMAGING WIND THREAT.
HIGH TEMPERATURES WILL REACH THE UPPER 80S AND LOW 90S ALONG THE
COASTAL PLAIN WHERE SOME HEATING WILL OCCUR BEFORE THUNDERSTORMS
ARRIVE. LINGERING HUMIDITY WILL ALLOW HEAT INDEX VALUES TO REACH
THE UPPER 90S BUT SHOULD NOT REACH HEAT ADVISORY LEVELS.
WITH THE COLD FRONT PUSHING OFFSHORE AND DRY HIGH PRESSURE
BUILDING IN BEHIND IT... EXPECT A BREAK FROM THE HUMID WEATHER AND
A RETURN TO MORE SEASONABLE TEMPERATURES. LOWS WILL REACH THE 50S
AND LOW 60S.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
SUNDAY WILL FINALLY BRING AN END TO THE HEAT AND HUMIDITY...WITH
DEW POINTS DROPPING INTO 50S AND HIGHS IN THE 70S TO AROUND 80...
UNDER MAINLY SUNNY SKIES. THE HIGH SHOULD STAY IN PLACE BENEATH
MAINLY ZONAL FLOW ALOFT THROUGH TUESDAY...WITH SEASONABLE TEMPS
AND RH LEVELS.
MODELS SUGGESTING SEVERAL 500MB WAVES TRACKING OUT ACROSS THE GREAT
LAKES TUESDAY INTO THE END OF THE WEEK...CARVING OUT A LARGER SCALE
TROUGH OVER THE EASTERN THIRD OF THE CONUS. THERE WILL BE A COUPLE
CHANCES FOR PRECIP AS THESE WAVES MOVE THROUGH...THE FIRST OF WHICH
LOOKS TO BE TUESDAY NIGHT OR WEDNESDAY. AS THE 500 MB TROUGH DIGS
TO THE WEST...WILL SEE AN INCREASE IN MOISTURE...WITH MORE HUMID
CONDITIONS RETURNING MID-LATE WEEK.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
SHORT TERM...GUSTY SOUTHWEST WINDS WILL SUBSIDE SOMEWHAT LATE THIS
AFTERNOON. THUNDERSTORMS ARE POSSIBLE MAINLY THIS EVENING IN
NORTHERN AREAS... THOUGH THERE COULD BE A THUNDERSTORM OR TWO OVER
SOUTHERN NEW HAMPSHIRE THIS AFTERNOON. DESPITE CONTINUED HUMID
WEATHER... DO NOT EXPECT FOG TONIGHT. FOG LAST NIGHT WAS DUE TO
INCREASING DEW POINTS OVERNIGHT... WHILE THEY SHOULD HOLD STEADY
TONIGHT WITH WINDS STAYING IN THE 5 TO 10 KNOT RANGE.
THUNDERSTORMS ARE LIKELY ON SATURDAY DURING THE DAY AS A COLD
FRONT MOVES THROUGH.
LONG TERM...MAINLY VFR THROUGH WEDNESDAY. SOME VALLEY FOG WILL BE
POSSIBLE SUNDAY AND MONDAY NIGHT WITH RESTRICTIONS POSSIBLE IN FOG
AND COASTAL STRATUS TUESDAY NIGHT.
&&
.MARINE...
SHORT TERM...SMALL CRAFT ADVISORY CONTINUES FOR THE OUTER WATERS.
ALTHOUGH 850 MB WIND SPEEDS ARE 30 TO 35 KNOTS... THE INVERSION
THAT LIKELY EXISTS OVER THE COOLER WATERS IN THIS ENVIRONMENT WILL
PREVENT WIND GUSTS FROM GETTING MUCH ABOVE 20 TO 25 KT. THE
PERSISTENT SOUTHWEST FLOW WILL ALLOW SEAS TO BUILD THROUGH
TONIGHT... BUT MODELS TEND TO OVERDO THE WAVE HEIGHTS ON SOUTHWEST
FLOW. STILL MAY SEE SOME 5 FT SEAS IN EASTERN AREAS BY MORNING.
SEAS SHOULD SUBSIDE FROM SOUTHWEST TO NORTHEAST DURING THE DAY ON
SATURDAY.
LONG TERM...WATERS SHOULD BE QUIET SUNDAY THROUGH WEDNESDAY...WITH
LIGHT WINDS...AND SEAS BELOW 5FT.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR MEZ012-018>021-
023-024.
NH...EXCESSIVE HEAT WARNING UNTIL 7 PM EDT THIS EVENING FOR NHZ010-
013-014.
HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR NHZ006-008-009.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR ANZ150-152.
SMALL CRAFT ADVISORY UNTIL NOON EDT SATURDAY FOR ANZ154.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
319 PM EDT FRI JUL 19 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION ON SATURDAY...PRODUCING
POTENTIALLY SEVERE STORMS. BEHIND THIS FRONT...COOLER AND LESS
HUMID HIGH PRESSURE WILL BUILD IN...BRINGING AN END TO OUR HEAT
WAVE. THIS HIGH HOLD FOR SUNDAY THROUGH TUESDAY...WITH HIGHS IN THE
70S TO LOW 80S...AND OVERNIGHT LOWS IN THE 50S TO AROUND 60. WEAK
LOW PRESSURE WILL MOVE THROUGH SOUTHERN NEW ENGLAND TUESDAY NIGHT
AND WEDNESDAY...PROVIDING THE NEXT CHANCE OF SHOWERS OR
THUNDERSTORMS.
&&
.NEAR TERM /TONIGHT/...
HOT AND HUMID CONDITIONS ACROSS THE COASTAL PLAIN WILL GIVE WAY TO
A WARM AND MUGGY NIGHT. DEW POINTS WILL ONCE AGAIN BE IN THE
70S... AND LOW TEMPERATURES WILL ONLY REACH THE LOW TO MID 70S FOR
MUCH OF THE COASTAL PLAIN. THIS WILL MAKE IT DIFFICULT FOR HOT
BUILDINGS THAT BAKED IN THE HEAT TODAY TO COOL OFF MUCH OVERNIGHT
WITHOUT THE HELP OF AIR CONDITIONING.
SHOWER AND THUNDERSTORM ACTIVITY HAS FAILED TO DEVELOP THIS
AFTERNOON OVER THE FORECAST AREA... BUT EXPECT SOME DEVELOPMENT
OVER THE HIGHER TERRAIN OF NEW YORK STATE AND SOUTHERN VERMONT.
THIS MAY MOVE INTO SOUTHERN NEW HAMPSHIRE AND SOUTHWEST MAINE THIS
EVENING. OTHER MORE WIDESPREAD SHOWERS AND STORMS HAVE FORMED A
LINE IN SOUTHEAST ONTARIO AND SOUTHERN QUEBEC... MOVING TOWARD
MONTREAL. THIS WILL LIKELY HOLD TOGETHER AND BEGIN IMPACTING FAR
NORTHERN MAINE ZONES BY 6 PM. OTHER DEVELOPMENT FURTHER WEST MAY
ALSO MOVE INTO THE NORTHERN PORTIONS OF THE FORECAST AREA AROUND 9
PM. THE HRRR MODEL IS ONCE AGAIN HANDLING THIS ACTIVITY QUITE
WELL. DAMAGING WINDS AND HEAVY RAINFALL WILL BE A THREAT WITH
THESE STORMS ESPECIALLY AS THEY FORM A LINE WITH EMBEDDED BOWING
SEGMENTS.
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
EXPECT THE COLD FRONT TO BE PUSHING INTO NORTHERN AREAS BY
SATURDAY MORNING... WITH SHOWERS AND THUNDERSTORMS ALONG AND AHEAD
OF IT. MAY HAVE ACTIVITY ONGOING AT 8 AM... PROGRESSING SOUTHEAST
ACROSS THE FORECAST AREA THROUGH THE AFTERNOON. THUNDERSTORM
CHANCES DIMINISH THROUGH THE LATE AFTERNOON AS THE FRONT PUSHES
OFFSHORE. WIND SHEAR WILL BE SUPPORTIVE FOR STORM ORGANIZATION AND
A DAMAGING WIND THREAT.
HIGH TEMPERATURES WILL REACH THE UPPER 80S AND LOW 90S ALONG THE
COASTAL PLAIN WHERE SOME HEATING WILL OCCUR BEFORE THUNDERSTORMS
ARRIVE. LINGERING HUMIDITY WILL ALLOW HEAT INDEX VALUES TO REACH
THE UPPER 90S BUT SHOULD NOT REACH HEAT ADVISORY LEVELS.
WITH THE COLD FRONT PUSHING OFFSHORE AND DRY HIGH PRESSURE
BUILDING IN BEHIND IT... EXPECT A BREAK FROM THE HUMID WEATHER AND
A RETURN TO MORE SEASONABLE TEMPERATURES. LOWS WILL REACH THE 50S
AND LOW 60S.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
SUNDAY WILL FINALLY BRING AN END TO THE HEAT AND HUMIDITY...WITH
DEW POINTS DROPPING INTO 50S AND HIGHS IN THE 70S TO AROUND 80...
UNDER MAINLY SUNNY SKIES. THE HIGH SHOULD STAY IN PLACE BENEATH
MAINLY ZONAL FLOW ALOFT THROUGH TUESDAY...WITH SEASONABLE TEMPS
AND RH LEVELS.
MODELS SUGGESTING SEVERAL 500MB WAVES TRACKING OUT ACROSS THE GREAT
LAKES TUESDAY INTO THE END OF THE WEEK...CARVING OUT A LARGER SCALE
TROUGH OVER THE EASTERN THIRD OF THE CONUS. THERE WILL BE A COUPLE
CHANCES FOR PRECIP AS THESE WAVES MOVE THROUGH...THE FIRST OF WHICH
LOOKS TO BE TUESDAY NIGHT OR WEDNESDAY. AS THE 500 MB TROUGH DIGS
TO THE WEST...WILL SEE AN INCREASE IN MOISTURE...WITH MORE HUMID
CONDITIONS RETURNING MID-LATE WEEK.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
SHORT TERM...GUSTY SOUTHWEST WINDS WILL SUBSIDE SOMEWHAT LATE THIS
AFTERNOON. THUNDERSTORMS ARE POSSIBLE MAINLY THIS EVENING IN
NORTHERN AREAS... THOUGH THERE COULD BE A THUNDERSTORM OR TWO OVER
SOUTHERN NEW HAMPSHIRE THIS AFTERNOON. DESPITE CONTINUED HUMID
WEATHER... DO NOT EXPECT FOG TONIGHT. FOG LAST NIGHT WAS DUE TO
INCREASING DEW POINTS OVERNIGHT... WHILE THEY SHOULD HOLD STEADY
TONIGHT WITH WINDS STAYING IN THE 5 TO 10 KNOT RANGE.
THUNDERSTORMS ARE LIKELY ON SATURDAY DURING THE DAY AS A COLD
FRONT MOVES THROUGH.
LONG TERM...MAINLY VFR THROUGH WEDNESDAY. SOME VALLEY FOG WILL BE
POSSIBLE SUNDAY AND MONDAY NIGHT WITH RESTRICTIONS POSSIBLE IN FOG
AND COASTAL STRATUS TUESDAY NIGHT.
&&
.MARINE...
SHORT TERM...SMALL CRAFT ADVISORY CONTINUES FOR THE OUTER WATERS.
ALTHOUGH 850 MB WIND SPEEDS ARE 30 TO 35 KNOTS... THE INVERSION
THAT LIKELY EXISTS OVER THE COOLER WATERS IN THIS ENVIRONMENT WILL
PREVENT WIND GUSTS FROM GETTING MUCH ABOVE 20 TO 25 KT. THE
PERSISTENT SOUTHWEST FLOW WILL ALLOW SEAS TO BUILD THROUGH
TONIGHT... BUT MODELS TEND TO OVERDO THE WAVE HEIGHTS ON SOUTHWEST
FLOW. STILL MAY SEE SOME 5 FT SEAS IN EASTERN AREAS BY MORNING.
SEAS SHOULD SUBSIDE FROM SOUTHWEST TO NORTHEAST DURING THE DAY ON
SATURDAY.
LONG TERM...WATERS SHOULD BE QUIET SUNDAY THROUGH WEDNESDAY...WITH
LIGHT WINDS...AND SEAS BELOW 5FT.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR MEZ012-018>021-
023-024.
NH...EXCESSIVE HEAT WARNING UNTIL 7 PM EDT THIS EVENING FOR NHZ010-
013-014.
HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR NHZ006-008-009.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT SATURDAY FOR ANZ150-152.
SMALL CRAFT ADVISORY UNTIL NOON EDT SATURDAY FOR ANZ154.
&&
$$
SYNOPSIS...CEMPA
NEAR TERM...KIMBLE
SHORT TERM...KIMBLE
LONG TERM...CEMPA
AVIATION...CEMPA/KIMBLE
MARINE...CEMPA/KIMBLE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
715 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 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 715 PM EDT SAT JUL 20 2013
VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD AS HIGH
PRESSURE REMAINS OVER THE REGION.
&&
.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...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
548 PM EDT FRI JUL 19 2013
LATEST UPDATE...
MESOSCALE DISCUSSION
.MESOSCALE DISCUSSION...
ISSUED AT 545 PM EDT FRI JUL 19 2013
I BELIEVE WE STILL HAVE SOME POTENTIAL FOR A LINE OF STRONG TO
SEVERE STORMS TO DEVELOP JUST AHEAD OF THE COLD FRONT AS IT MOVES
SLOWLY SOUTH THROUGH OUR CWA EARLY TONIGHT. CURRENTLY THERE ARE
SCATTERED STORMS AHEAD OF THE FRONT OVER NORTHERN LOWER. HOWEVER
THERE IS A SPEED MAX (SEEN ON THE WATER VAPOR IMAGE LOOP) OVER
CNTL MN/WI AT 532 PM HEADING TOWARD NORTHERN LOWER MICHIGAN. THAT
WILL BE OVER NORTHERN LOWER MICHIGAN IN THE 8 PM TO MIDNIGHT TIME
FRAME. I EXPECT THE LINE TO FILL IN WITHIN THE NEXT HOUR OR TWO.
THEN CONTINUE TO MOVE SOUTH SIMILAR TO THE 20Z HRRR SHOWS IT
DOING. AS A RESULT I PLAN ON KEEPING OUR SEVERE THUNDERSTORM WATCH
IN PLACE FOR NOW.
&&
.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 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 148 PM EDT FRI JUL 19 2013
GENERALLY VFR CIGS/VSBYS EXPECTED THROUGH THE PERIOD. THERE MAY BE
SHOWERS PERHAPS A TSRA IN THE VICINITY OF THE TAF SITES LATER THIS
AFTERNOON. HOWEVER LATEST VIS LOOP SHOWS WEST WIND HAVE SCOURED
OUT THE CU ACROSS MUCH OF THE AREA. THINK THE BETTER CHANCE OF
STORMS WILL BE AFTER 10 PM WHEN THE MAIN COLD FRONT STARTS TO MOVE
SOUTH ACROSS THE LOWER PENINSULA. NOT CONVINCED WE/LL SEE A SOLID
LINE OF STORMS ALONG THE FRONT SO LEFT THE VCTS COMMENT IN THE TAFS.
&&
.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.
&&
$$
MESOSCALE...WDM
SYNOPSIS...DUKE
SHORT TERM...DUKE
LONG TERM...MACZKO
AVIATION...93
HYDROLOGY...DUKE
MARINE...DUKE
AREA FORECAST DISCUSSION
NWS GAYLORD MI
132 AM EDT FRI JUL 19 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.
&&
.UPDATE...
ISSUED AT 113 AM EDT FRI JUL 19 2013
CHANCES FOR PRECIPITATION NEEDED UPDATING FOR TIMING/COVERAGE OF
BAND OF RAIN SHOWERS AND EMBEDDED ISOLATED THUNDER (INSTABILITY
REALLY LESS THAN DESIRABLE). THIS BAND WAS DROPPING THROUGH
EASTERN UPPER AND WILL MAKE IT TO AND THROUGH THE STRAITS...WHILE
A SECONDARY BAND OF SHOWERS BEGINS TO DROP SOUTHWARD AND BACK INTO
EASTERN UPPER AND NE WISCONSIN. LESS CONFIDENCE IN THIS...AS IT
MAY TAKE UNTIL THE DAYLIGHT HOURS FOR THIS TO ARRIVE. THUS...A
LULL IN THE ACTION OVERNIGHT? SKY NEEDED FIXING AS WELL...WITH
CLEAR SKIES ACROSS MOST OF NRN LOWER...AND THIS WILL LIKELY
CONTINUE THROUGH THE NIGHT UNTIL SAID NEXT BAND OF SHOWERS/STORMS
ARRIVES IN THE DAYLIGHT HOURS.
UPDATE ISSUED AT 1005 PM EDT THU JUL 18 2013
SEVERE THUNDERSTORM WATCH CONTINUES LATE THIS EVENING FOR ERN UPR
MICHIGAN AND THE TIP OF THE MITT. CONVECTIVE LINE (LEWP) HAS
SPREAD ACROSS ALL OF ERN UPR MICHIGAN...WITH THE LEADING EDGE NOW
IN THE STRAITS AREA. A FEW STORMS WITHIN THIS LINE HAVE BECOME
VERY STRONG/LOW END SEVERE...BUT DID SHOW AN OVERALL DOWNWARD
TREND IN INTENSITY AS IT ENTERED OUR NRN ZONES. AT THIS
POINT...WILL KEEP THE WATCH GOING GIVEN THE POTENTIAL FOR A FEW
ADDITIONAL STRONG/SEVERE STORMS IN RESPONSE TO STRENGTHEN WIND
SHEAR AS A 45 TO 50 KT JET MAX LEANS INTO THE AREA LATE TONIGHT.
WILL ALSO KEEP AN EYE ON THE NEXT LINE OF CONVECTION NOW MOVING
E/SE THRU CENTRAL LAKE SUPERIOR AS WE HEAD INTO THE OVERNIGHT
HOURS.
UPDATE ISSUED AT 742 PM EDT THU JUL 18 2013
DIURNAL ENHANCEMENT TO CONVECTION IS QUICKLY DIMINISHING WITH THE
APPROACH OF SUNSET...BRINGING AN END TO THE WIDELY SCATTERED
SHOWERS AND STORMS ACROSS ALL OF NRN LWR MICHIGAN. AFTERNOON
CONVECTION OVER LAKE SUPERIOR HAS FURTHER ORGANIZED INTO A LEWP...
EXTENDING FROM JUST NORTH OF WHITEFISH BAY WESTWARD ALONG THE LAKE
SUPERIOR SHORELINE OF CENTRAL AND ERN UPR MICHIGAN. ADDITIONAL
SCATTERED SHOWERS AND STORMS HAVE DEVELOPED AHEAD OF THIS LINE OF
CONVECTION...WITH THESE CELLS AND THE WHOLE LINE MOVING E/SE. THIS
LINE OF CONVECTION WILL SLIDE THRU ERN UPR MICHIGAN AND THE
STRAITS DURING THE BALANCE OF THE EVENING. VELOCITY DATA HAS SHOWN
SOME EMBEDDED AREAS OF ROTATION WITHIN THE THE LINE...AND WILL
CERTAINLY MONITOR RADAR AS THIS LINE SLIDES THRU OUR NRN CWA.
OVERALL AHEAD WILL STRENGTHEN THRU THE NIGHT AS AS 45 TO 50 KT LOW
LEVEL JET MAX LEANS INTO NRN MICHIGAN. PLENTY OF SURFACE BASED
INSTABILITY WILL REMAIN IN TACT AS WE HEAD THRU THE NIGHT...AS
WILL AMPLE 850 MB THETA E.
&&
.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 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 113 AM EDT FRI JUL 19 2013
OVERALL CONDITIONS WILL REMAIN VFR THRU MOST OF THE 24 HR TAF
FORECAST PERIOD...HOWEVER CHANCES OF SHOWERS AND STORMS WILL
STEADILY INCREASE OVERNIGHT AND INTO FRIDAY AS A COLD FRONT DROPS
SE THRU NRN MICHIGAN. LOW LEVEL SW FLOW WILL CONTINUE TO INCREASE
AHEAD OF THE FRONT...LENDING TO LLWS THRU THIS MORNING. LOW LEVEL
WINDS WILL BE STRONGER IN AND AROUND THUNDERSTORMS. THE COLD FRONT
WILL CLEAR NRN LWR MICHIGAN BY LATE AFTERNOON...WITH MVFR CIGS
DEVELOPING BEHIND THE FRONT FOR THE EVENING HOURS.
&&
.MARINE...
ISSUED AT 130 AM EDT FRI JUL 19 2013
UPDATED THE SMALL CRAFT ADVISORIES TO INCLUDE ALL OF THE NW LOWER
LAKE MICHIGAN NEARSHORES....INCLUDING GRAND TRAVERSE BAY. THIS WAS
ALREADY OUT...BUT TOOK OUT SEUL CHOIX TO THE BRIDGE...AND ADDED
PORTIONS OF LAKE HURON NEARSHORES. GRADIENT WINDS OF 35KTS...EVEN
WITH THE STABILITY...WILL LIKELY RESULT IN LOW END ADVISORY GUSTS
PRIOR TO A COLD FRONTAL PASSAGE FRIDAY.
IN ADDITION...GUSTY OUTFLOW FROM BAND OF SHOWER SAND ISOLATED
THUNDER DROPPING INTO EASTERN UPPER WILL RESULT IN TEMPORARY
ADVISORY LEVEL GUSTS. WILL HANDLE THIS WITH AN MWS. MARGINAL
SCA/S MAY AGAIN BE NECESSARY ON SATURDAY GIVEN STRENGTHENING
NORTHWEST FLOW.
BEHIND THE FRONT FOR FRIDAY NIGHT AND SATURDAY MORNING...THE
STRENGTHENING NW WINDS ARE A RESULT OF A SECONDARY COLD FRONTAL
PASSAGE. HIGH PRESSURE THEN BUILDS IN FOR THE REMAINDER OF THE
WEEKEND.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...HEAT ADVISORY UNTIL 8 AM EDT THIS MORNING FOR MIZ016>034.
HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR MIZ035-036-041-042.
LH...SMALL CRAFT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR LHZ349.
LM...SMALL CRAFT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR LMZ323-342-
344>346.
LS...NONE.
&&
$$
UPDATE...SD
SYNOPSIS...JPB
SHORT TERM...ARNOTT
LONG TERM...JPB
AVIATION...SD
MARINE...ARNOTT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
203 PM CDT FRI JUL 19 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 459 AM CDT FRI JUL 19 2013
OUR MPX WRF AND HOP WRF ARE ON SIMILAR PATHS WITH THE SHOWER AND
THUNDERSTORM ACTIVITY EXITING OUR AREA BY 12Z. FOR TODAY...A BREAK
FROM THE HEAT AND HUMIDITY WILL BE NOTED WITH SOME SCATTERED
CLOUDS...EXCEPT FOR SOUTHWEST MN WHICH MAY BE CLOUD FREE. VERY DRY
AIR ABOVE 6000 FEET WILL CONTINUE WORKING ITS ITS WAY INTO WESTERN
MN. THERE IS SOME LOW LEVEL MOISTURE ACROSS EASTERN MN AND WESTERN
WI. THE RAP KEEPS THIS MOISTURE IN PLACE UNTIL MID AFTERNOON. SHOULD
BE PLENTY OF MIXING SO DO NOT EXPECT MORE THAN SCATTERED
CLOUDS...EXCEPT SW MN WHERE IT MAY BE CLEAR. MAY BE CLEAR AFTER 21Z
IN MOST AREAS AS DRIER AIR FILTERS IN. OVERNIGHT A SECONDARY COLD
FRONT USHERS IN COOLER AIR AND BY SATURDAY MORNING A DISTURBANCE
MOVES TOWARD WESTERN MN WITH AN INCREASE IN MOISTURE. NO
PRECIPITATION EXPECTED THROUGH 12Z SATURDAY.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 459 AM CDT FRI JUL 19 2013
THE LONG TERM PORTION OF THE FORECAST WILL FEATURE RIDGING OVER THE
ROCKIES...WITH EPISODIC IMPULSES PARADING ACROSS THE NORTHERN CONUS.
THE FIRST OF THESE SHORTWAVES HAS BEEN CONSISTENTLY PROGGED TO
ARRIVE ON SATURDAY NIGHT INTO SUNDAY BY DETERMINISTIC AND ENSEMBLE
SOLUTIONS. FAIRLY IMPRESSIVE LIFT FROM 305-310K IS PROGGED TO
BLOSSOM OVER THE AREA BETWEEN 06Z AND 12Z SUNDAY AS 925-850 MOISTURE
TRANSPORT NOSES INTO SOUTHERN MN. HAVE INCLUDED 50-60 POPS FOR THIS
TIME FRAME.
NORTHWEST FLOW PERSISTS THROUGH THE BEGINNING OF NEXT WEEK...WHICH WILL
NECESSITATE THE INCLUSION OF 20-30 POPS FOR A LONG DURATION. THE
TUESDAY INTO WEDNESDAY TIME FRAME IS TRENDING DRIER HOWEVER...AS
DRY SURFACE HIGH PRESSURE BUILDS IN...SO MAY BE ABLE TO SHED
SHOWER AND THUNDERSTORM CHANCES FOR THOSE DAYS.
WEDNESDAY NIGHT INTO FRIDAY LOOK WET AGAIN HOWEVER....AS SHORTWAVE
ENERGY CHANNELS THROUGH THE WESTERN PERIPHERY OF THE ONTARIO LOW.
TEMPERATURES WILL REMAIN RELATIVELY STATIC THROUGH THE EXTENDED
PERIOD...WITH HIGHS GENERALLY IN THE MID 70S TO LOWER 80S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 134 PM CDT FRI JUL 19 2013
NO PROBLEMS IN THE SHORT TERM. WE SHOULD LARGELY REMAIN DRY WITH
VFR CONDITIONS TONIGHT AND MOST OF THE DAY TOMORROW. YOU WILL
NOTICE A SMALL AREA OF THUNDERSTORMS NEAR THE ND/CANADIAN BORDER
THIS AFTERNOON. IT IS POSSIBLE SOME OF THIS ACTIVITY WILL MAKE IT
INTO WESTERN AND CENTRAL MN TONIGHT. INCLUDED A VCSH AT KAXN AND
KRWF...BUT SHOWERS WILL BE WIDELY SCATTERED IF THEY OCCUR AT ALL.
WE MAY END UP SEEING A FEW MORE MID CLOUDS LATE TONIGHT.
KMSP...
AS MENTIONED ABOVE...WE HAVE A GOOD CHANCE OF REMAINING DRY
TONIGHT AND AT WORSE THE AIRPORT WILL SEE A LIGHT SHOWER OR A FEW
SPRINKLES JUST BEFORE SUNRISE. VFR IS EXPECTED.
/OUTLOOK FOR KMSP/
SAT NIGHT...MAINLY VFR. SLGT CHC -SHRA/-TSRA. NW WINDS 5-10 KTS.
SUN...MAINLY VFR. CHC -SHRA/-TSRA. NE WINDS 5-10 KTS.
MON...MAINLY VFR. CHC -SHRA/TSRA. SE-S WINDS 5 TO 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...DRL
LONG TERM...LS
AVIATION...CLF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
655 AM CDT FRI JUL 19 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 459 AM CDT FRI JUL 19 2013
OUR MPX WRF AND HOP WRF ARE ON SIMILAR PATHS WITH THE SHOWER AND
THUNDERSTORM ACTIVITY EXITING OUR AREA BY 12Z. FOR TODAY...A BREAK
FROM THE HEAT AND HUMIDITY WILL BE NOTED WITH SOME SCATTERED
CLOUDS...EXCEPT FOR SOUTHWEST MN WHICH MAY BE CLOUD FREE. VERY DRY
AIR ABOVE 6000 FEET WILL CONTINUE WORKING ITS ITS WAY INTO WESTERN
MN. THERE IS SOME LOW LEVEL MOISTURE ACROSS EASTERN MN AND WESTERN
WI. THE RAP KEEPS THIS MOISTURE IN PLACE UNTIL MID AFTERNOON. SHOULD
BE PLENTY OF MIXING SO DO NOT EXPECT MORE THAN SCATTERED
CLOUDS...EXCEPT SW MN WHERE IT MAY BE CLEAR. MAY BE CLEAR AFTER 21Z
IN MOST AREAS AS DRIER AIR FILTERS IN. OVERNIGHT A SECONDARY COLD
FRONT USHERS IN COOLER AIR AND BY SATURDAY MORNING A DISTURBANCE
MOVES TOWARD WESTERN MN WITH AN INCREASE IN MOISTURE. NO
PRECIPITATION EXPECTED THROUGH 12Z SATURDAY.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 459 AM CDT FRI JUL 19 2013
THE LONG TERM PORTION OF THE FORECAST WILL FEATURE RIDGING OVER THE
ROCKIES...WITH EPISODIC IMPULSES PARADING ACROSS THE NORTHERN CONUS.
THE FIRST OF THESE SHORTWAVES HAS BEEN CONSISTENTLY PROGGED TO
ARRIVE ON SATURDAY NIGHT INTO SUNDAY BY DETERMINISTIC AND ENSEMBLE
SOLUTIONS. FAIRLY IMPRESSIVE LIFT FROM 305-310K IS PROGGED TO
BLOSSOM OVER THE AREA BETWEEN 06Z AND 12Z SUNDAY AS 925-850 MOISTURE
TRANSPORT NOSES INTO SOUTHERN MN. HAVE INCLUDED 50-60 POPS FOR THIS
TIME FRAME.
NORTHWEST FLOW PERSISTS THROUGH THE BEGINNING OF NEXT WEEK...WHICH WILL
NECESSITATE THE INCLUSION OF 20-30 POPS FOR A LONG DURATION. THE
TUESDAY INTO WEDNESDAY TIME FRAME IS TRENDING DRIER HOWEVER...AS
DRY SURFACE HIGH PRESSURE BUILDS IN...SO MAY BE ABLE TO SHED
SHOWER AND THUNDERSTORM CHANCES FOR THOSE DAYS.
WEDNESDAY NIGHT INTO FRIDAY LOOK WET AGAIN HOWEVER....AS SHORTWAVE
ENERGY CHANNELS THROUGH THE WESTERN PERIPHERY OF THE ONTARIO LOW.
TEMPERATURES WILL REMAIN RELATIVELY STATIC THROUGH THE EXTENDED
PERIOD...WITH HIGHS GENERALLY IN THE MID 70S TO LOWER 80S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 643 AM CDT FRI JUL 19 2013
VFR ON TAP FOR THE DAY TODAY AT ALL TAF SITES. LOW LEVEL MOISTURE
TO REMAIN IN PLACE MOST OF THE DAY OVER THE EASTERN AREAS. DRIER
AIR MOVES INTO THE WESTERN AREAS TODAY WITH VERY DRY CONDITIONS
ABOVE 6000 FEET. WITH GOOD MIXING WOULD NOT BE SURPRISED TO SEE
SKC AT AXN/RWF. THE OTHER SITES SHOULD BE SCATTERED BECOMING SKC
BY EVENING. WITH THE MIXING COMES FAIRLY GUSTY WINDS BY MID
MORNING AND LASTING INTO THE EVENING HOURS. AS A DISTURBANCE
APPROACHES THE STATE SATURDAY MORNING WE WILL SEE A RETURN TO
SCATTERED TO BROKEN CLOUDS AND A CHANCE FOR PRECIPITATION ESPECIALLY IN
THE WEST LATER SATURDAY.
KMSP...VFR THROUGH THE PERIOD. BKN MID DECK SHOULD GIVE WAY TO SCT
THEN FEW BY 00Z. GUSTY NORTHWEST WINDS TODAY.
/OUTLOOK FOR KMSP/
SAT...MAINLY VFR. SLGT CHC -SHRA/-TSRA IN THE LATE AFTERNOON. NW
WINDS 5-10 KTS.
SUN...MAINLY VFR. CHC -SHRA/-TSRA. NE WINDS 5-10 KTS.
MON...MAINLY VFR. CHC -SHRA/TSRA. SE-S WINDS 5 TO 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...DRL
LONG TERM...LS
AVIATION...DRL
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
459 AM CDT FRI JUL 19 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 459 AM CDT FRI JUL 19 2013
OUR MPX WRF AND HOP WRF ARE ON SIMILAR PATHS WITH THE SHOWER AND
THUNDERSTORM ACTIVITY EXITING OUR AREA BY 12Z. FOR TODAY...A BREAK
FROM THE HEAT AND HUMIDITY WILL BE NOTED WITH SOME SCATTERED
CLOUDS...EXCEPT FOR SOUTHWEST MN WHICH MAY BE CLOUD FREE. VERY DRY
AIR ABOVE 6000 FEET WILL CONTINUE WORKING ITS ITS WAY INTO WESTERN
MN. THERE IS SOME LOW LEVEL MOISTURE ACROSS EASTERN MN AND WESTERN
WI. THE RAP KEEPS THIS MOISTURE IN PLACE UNTIL MID AFTERNOON. SHOULD
BE PLENTY OF MIXING SO DO NOT EXPECT MORE THAN SCATTERED
CLOUDS...EXCEPT SW MN WHERE IT MAY BE CLEAR. MAY BE CLEAR AFTER 21Z
IN MOST AREAS AS DRIER AIR FILTERS IN. OVERNIGHT A SECONDARY COLD
FRONT USHERS IN COOLER AIR AND BY SATURDAY MORNING A DISTURBANCE
MOVES TOWARD WESTERN MN WITH AN INCREASE IN MOISTURE. NO
PRECIPITATION EXPECTED THROUGH 12Z SATURDAY.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 459 AM CDT FRI JUL 19 2013
THE LONG TERM PORTION OF THE FORECAST WILL FEATURE RIDGING OVER THE
ROCKIES...WITH EPISODIC IMPULSES PARADING ACROSS THE NORTHERN CONUS.
THE FIRST OF THESE SHORTWAVES HAS BEEN CONSISTENTLY PROGGED TO
ARRIVE ON SATURDAY NIGHT INTO SUNDAY BY DETERMINISTIC AND ENSEMBLE
SOLUTIONS. FAIRLY IMPRESSIVE LIFT FROM 305-310K IS PROGGED TO
BLOSSOM OVER THE AREA BETWEEN 06Z AND 12Z SUNDAY AS 925-850 MOISTURE
TRANSPORT NOSES INTO SOUTHERN MN. HAVE INCLUDED 50-60 POPS FOR THIS
TIME FRAME.
NORTHWEST FLOW PERSISTS THROUGH THE BEGINNING OF NEXT WEEK...WHICH WILL
NECESSITATE THE INCLUSION OF 20-30 POPS FOR A LONG DURATION. THE
TUESDAY INTO WEDNESDAY TIMEFRAME IS TRENDING DRIER HOWEVER...AS
DRY SURFACE HIGH PRESSURE BUILDS IN...SO MAY BE ABLE TO SHED
SHOWER AND THUNDERSTORM CHANCES FOR THOSE DAYS.
WEDNESDAY NIGHT INTO FRIDAY LOOK WET AGAIN HOWEVER....AS SHORTWAVE
ENERGY CHANNELS THROUGH THE WESTERN PERIPHERY OF THE ONTARIO LOW.
TEMPERATURES WILL REMAIN RELATIVELY STATIC THROUGH THE EXTENDED
PERIOD...WITH HIGHS GENERALY IN THE MID 70S TO LOWER 80S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1149 PM CDT THU JUL 18 2013
HAVE SCALED BACK PRECIP CHCS IN THE 06Z ISSUANCE AS MIDLVL RIDGING
HAS PREVENTED MUCH IN THE WAY OF CONVECTIVE DEVELOPMENT FROM
DROPPING S FROM NRN MN. THAT SAID...ISOLD ECHOES HAVE BEGUN TO
SHOW UP IN W-CENTRAL MN ON THE KMPX RADAR. HOWEVER...LATEST SHORT-
TERM MODEL RNUS INDICATE VERY LITTLE TO NEARLY NO CONVECTIVE
ACTIVITY WILL IMPACT THE TERMINALS. LATEST POP UPDATE HAS DROPPED
PRECIP CHCS TO NO HIGHER THAN 30 PERCENT SO HAVE OPTED TO RUN WITH
A DRY FCST WITH CONFIDENCE QUITE LOW IN PREDICTING CONVECTION TO
IMPACT ANY TERMINAL. CLOUD COVER WILL INCRS OVERNIGHT...LIKELY TO
RESULT IN MIDLVL CIGS BUT STILL WELL UP IN VFR RANGE. SKIES WILL
THEN STEADILY CLEAR OUT DURG THE DAY. MAINLY SW WINDS AT
INITIALIZATION IN THE 6-10KT RANGE FROM GRADUALLY VEER TO THE W
AND NW DURG THE DAY. SPEEDS WILL ALSO INCRS TO NEAR 15G25KT.
KMSP...RAN WITH VFR THIS FCST PERIOD AS PRECIP CHCS HAVE BEEN
REDUCED FOR THE FIRST 6 HRS OF THIS FCST. CLOUD COVER IS HARD TO
FIND OVER CENTRAL MN AT INITIALIZATION BUT ADDITIONAL OBS HAVE
STARTED TO REPORT SCT/BKN COVERAGE IN NRN AND W-CENTRAL MN. THESE
WILL GRADUALLY GET INTO MSP DURG THE EARLY MRNG HRS...MAKING FOR A
MIDLVL CIG. IF ANY PRECIP WERE TO OCCUR...BEST TIMING LOOKS TO BE
07Z-10Z...BUT WITH POPS LESS THAN 30 PERCENT...HAVE OPTED TO RUN
WITH A DRY FCST. SKIES THEN GRADUALLY CLEAR OUT STARTING AROUND
DAYBREAK THRU THE REST OF THE DAY. SW WINDS SETTLE DOWN TO THE 5-8
KT RANGE THEN VEER THROUGH DAYBREAK AS A CDFNT SLIPS S ACRS THE
AREA. WINDS GRADUALLY BECOME NW BY LATE MRNG AND INCRS TO THE
15G25KT AREA BEFORE SETTLING DOWN FRI EVE.
/OUTLOOK FOR KMSP/
SAT...MAINLY VFR. SLGT CHC -SHRA/-TSRA. NW WINDS 5-10 KTS.
SUN...MAINLY VFR. CHC -SHRA/-TSRA. SE WINDS 5-10 KTS.
MON...MAINLY VFR. CHC -SHRA/TSRA. S WINDS 5 TO 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...DRL
LONG TERM...LS
AVIATION...JPC
AREA FORECAST DISCUSSION
NWS DULUTH MN
1245 AM CDT FRI JUL 19 2013
.AVIATION.../00Z TAF ISSUANCE/
VFR CEILINGS WITH VCTS WILL BE COMMON THROUGH THE REMAINDER OF
THE NIGHT AS A COLD FRONT MARCHES EAST ACROSS THE REGION. THE
LINGERING SHOWERS AND STORMS WILL EXIT FRIDAY MORNING WITH
INCREASING NORTHWEST WINDS THROUGH THE DAY. WIDESPREAD GUSTS
AROUND 25 KT WILL BE FOUND BY FRIDAY AFTERNOON WITH MID LEVEL
SCT/BKN CEILINGS.
&&
PREV DISCUSSION... /ISSUED 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.
&&
.POINT TEMPS/POPS...
DLH 52 70 49 69 / 10 10 20 20
INL 46 69 48 73 / 10 10 10 10
BRD 55 75 52 76 / 10 10 20 30
HYR 53 75 50 74 / 10 10 20 20
ASX 52 69 48 70 / 10 10 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...FLASH FLOOD WATCH UNTIL 10 AM CDT THIS MORNING FOR MNZ011-012-
019>021.
WI...NONE.
LS...NONE.
&&
$$
AVIATION...GRANING
AREA FORECAST DISCUSSION
NWS GLASGOW MT
904 PM MDT SAT JUL 20 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH MONDAY...
9PM UPDATE...VERY ISOLATED THUNDERSTORMS CONTINUE IN THE
SOUTHEASTERN CORNER AND NORTHWESTERN CORNER OF THE FORECAST AREA.
DO EXPECT VERY ISOLATED THUNDERSTORM ACTIVITY TO CONTINUE THROUGH
THE REST OF TONIGHT MAINLY FOR THE NORTHERN AND EASTERN AREAS. PROTON
MADE ANOTHER UPDATE TO POPS AND WX GRIDS BASED ON THE LATEST
MOVEMENT OF THE THUNDERSTORMS. THESE STORMS ARE PRODUCING BRIEF
HEAVY RAIN...GUSTY WIND AND HAIL RANGING IN SIZE FROM DIME TO
QUARTER. THEY ARE EXPECT TO DEPART THE AREA BY MID EVENING. SCT
PREVIOUS UPDATE...
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...UPDATED
NWS BILLINGS MT
819 PM MDT SAT JUL 20 2013
.UPDATE...
KEEPING A CLOSE EYE ON A SEVERE THUNDERSTORM MOVING QUICKLY SE
THROUGH DAWSON COUNTY TO THE NE OF THE FORECAST AREA. HAVE
INCREASED POPS IN PATH OF THIS STORM OVER FALLON...NE CUSTER
COUNTY AND NORTHERN CARTER COUNTY THROUGH THE EVENING. MESO
ANALYSIS INDICATED 50 KT OF SHEAR OVER THE EASTERN PART OF THE
FORECAST AREA AND RAP KBHK SOUNDING HAD CAPES CLOSE TO 1000 J/KG.
JET ENERGY AND SHORTWAVES IN THE AREA WERE FUELING LIFT FOR THE
STORM. STORM WAS ALSO RIDING ALONG AN OUTFLOW BOUNDARY FROM
PREVIOUS STORMS OVER NE MT. OTHER FORECAST PARAMETERS WERE ON
TRACK. ARTHUR
&&
.SHORT TERM...VALID FOR SUN AND MON...
ISOLATED CONVECTION HAS DEVELOPED OVER THE SNOWIES THIS
AFTERNOON. ACTIVITY NOT MAKING IT VERY FAR OFF THE MOUNTAINS...SO
THOUGH ADDED LOW POPS TO AREAS NORTH...DID NOT GO TOO FAR EAST
WITH THEM THE REST OF THE AFTERNOON AND EVENING.
SUNDAY LOOKS TO BE VERY WARM AND DRY. 700MB TEMPERATURES APPROACH
13C WITH PRECIPITABLE WATER VALUES BELOW A HALF INCH FOR THE
WESTERN HALF OF THE AREA. A MID LEVEL FRONT IS PROGGED TO SLIDE
THROUGH DURING THE AFTERNOON AND THIS WILL HELP TO MIX THE
ATMOSPHERE DEEPLY. THIS WILL CAUSE DEWPOINTS TO CRASH IN THE
AFTERNOON WITH HUMIDITIES FALLING WELL INTO THE TEENS. SHORTWAVE
ACTIVITY WILL BE QUITE MINIMAL...SO NOT EXPECTING CONVECTION.
A SHORTWAVE TROUGH MOVES INTO NORTH CENTRAL MONTANA SUNDAY
AFTERNOON. DEWPOINTS WILL REMAIN LOW AND WILL THUS KEEP THE
CENTRAL AND WESTERN ZONES DRY. WILL BRUSH LOW POPS INTO THE
EASTERN ZONES AS A SURFACE LOW MOVES IN THERE FOR SOME LOW LEVEL
CONVERGENCE. LOW LEVEL WINDS WILL TURN EAST THERE TOO AND PROVIDE
ACCESS TO SLIGHTLY HIGHER DEWPOINTS. STORMS WILL HAVE GUSTY WINDS
WITH INVERTED V SOUNDINGS AND ELEVATED CAPE. MONDAY WILL STILL BE
WARM WITH THE MID LEVEL FRONT BEING COUNTERACTED BY MIXING. TWH
.LONG TERM...VALID FOR TUE...WED...THU...FRI...SAT...
MODELS CONTINUE TO BE IN FAIRLY GOOD AGREEMENT THROUGH THE
EXTENDED. CURRENT FORECAST LOOKS TO BE IN GOOD SHAPE SO DID NOT
MAKE ANY SIGNIFICANT CHANGES WITH THIS ISSUANCE. RIDGING BEGINS TO
BUILD ACROSS THE FORECAST AREA TUESDAY AND WEDNESDAY AND BECOMES A
BIT STRONGER BY THE END OF THE WEEK INTO NEXT WEEKEND. A FEW UPPER
LEVEL DISTURBANCES MAY MOVE NORTHEAST OUT OF THE GREAT BASIN AREA
AND POSSIBLY UNDERCUT THE RIDGE WEDNESDAY INTO THURSDAY.
HOWEVER...THE LATEST MODELS SHOW THE BULK OF THESE DISTURBANCES
MAY MOVE TO THE NORTH AND SOUTH OF OUR AREA WITH THE NORTHERN
PORTION MOVING ALONG THE RIDGE PERIPHERY ACROSS NORTHERN AND THEN
EASTERN MONTANA. AS A RESULT...BEST THUNDERSTORM CHANCES LOOK TO
BE ALONG THE MONTANA/WYOMING BORDER AND ACROSS EASTERN MONTANA.
AFTERNOON TEMPERATURES CONTINUE TO LOOK A FEW DEGREES ABOVE AND
BELOW NORMAL WITH READINGS IN THE MIDDLE 80S TO LOWER 90S. HOOLEY
&&
.AVIATION...
VFR WILL PREVAIL OVER THE AREA TONIGHT AND SAT. HOWEVER...AREAS E
AND SE OF KMLS WILL HAVE IFR TO VLIFR CONDITIONS THROUGH 06Z DUE
TO A STRONG TO SEVERE THUNDERSTORM MOVING INTO THE AREA. LARGE
HAIL...WIND GUSTS TO 60 KT AND VERY HEAVY RAINFALL WILL BE
POSSIBLE WITH THIS STORM. ARTHUR
&&
.PRELIMINARY POINT TEMP/POPS...
SUN MON TUE WED THU FRI SAT
-----------------------------------------------------------
BIL 060/093 061/092 061/090 061/091 062/086 060/087 061/088
10/U 01/U 00/U 11/U 12/T 22/T 12/T
LVM 046/092 047/092 049/090 052/091 054/085 052/087 053/088
00/U 00/U 00/U 01/U 12/T 22/T 11/B
HDN 059/094 059/094 059/089 060/091 061/087 058/087 060/090
10/U 01/U 00/U 11/U 22/T 22/T 12/T
MLS 062/094 062/092 063/089 062/090 064/087 062/087 063/090
10/N 02/T 21/U 11/U 22/T 22/T 12/T
4BQ 059/093 058/093 058/088 058/092 060/086 057/084 057/088
10/U 01/U 21/U 11/U 22/T 22/T 22/T
BHK 057/090 057/085 058/082 057/084 058/086 058/081 057/083
50/U 02/T 22/T 21/U 22/T 22/T 12/T
SHR 055/094 053/093 056/088 057/093 056/087 056/086 056/088
10/U 01/U 00/U 01/U 22/T 22/T 22/T
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS GLASGOW MT
654 PM MDT SAT JUL 20 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH MONDAY...
MADE ANOTHER UPDATE TO POPS AND WX GRIDS BASED ON THE LATEST
MOVEMENT OF THE THUNDERSTORMS. THESE STORMS ARE PRODUCING BRIEF
HEAVY RAIN...GUSTY WIND AND HAIL RANGING IN SIZE FROM DIME TO
QUARTER. THEY ARE EXPECT TO DEPART THE AREA BY MID EVENING. SCT
PREVIOUS UPDATE...
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 HASTINGS NE
944 PM CDT SAT JUL 20 2013
.UPDATE...
ISSUED AT 942 PM CDT SAT JUL 20 2013
AS WAS THE CASE DURING THE PRECEDING DAY SHIFT...CONFIDENCE IN
THUNDERSTORM TRENDS/RAIN CHANCES THROUGH THE OVERNIGHT HOURS
CONTINUES TO RUN AT LESS-THAN-IDEAL LEVELS. FOR AT LEAST A SHORT
TIME LONGER...THE ENTIRE CWA CONTINUES IN A MULTI-HOUR LULL IN THE
WAKE OF AFTERNOON CONVECTION THAT HAS SINCE EXITED WELL SOUTHEAST
OF THE CWA. ALTHOUGH AREAS FROM THE TRI-CITIES AND WEST/NORTHWEST
ESSENTIALLY MISSED OUT ON THE EARLIER ROUND...SEVERAL SMALL
POCKETS ACROSS NORTH CENTRAL KS AND FAR SOUTHERN NEB RECEIVED A
QUICK 1-4 INCH DRENCHING PER OUR LOCAL STORM REPORTS. LOOKING
AHEAD...THE ONLY SHOW IN TOWN AT THE 9 PM HOUR IS A SMALL LINEAR
COMPLEX OF STRONG TO MARGINALLY SEVERE STORMS TRACKING SOUTH-
SOUTHEAST THROUGH THE WEST CENTRAL/NORTH CENTRAL NEB
SANDHILLS...BUT GRADUALLY APPROACHING THE FRINGES OF THE CWA.
FARTHER UPSTREAM...ADDITIONAL CLUSTERS OF STRONG-SEVERE STORMS
HAVE TAKEN OFF IN SOUTHERN SD.
ON THE LARGE SCALE ALOFT...SEASONABLY DECENT WEST-NORTHWEST FLOW
WILL PERSIST THROUGH THE NIGHT MAINLY AT/ABOVE 500
MILLIBARS...WHILE FAIRLY CHAOTIC AND LIGHT FLOW PERSISTS A BIT
LOWER AT 700MB...AND LOWER YET EVEN THE FLOW AT 850MB APPEARS
QUITE UNDERWHELMING...WITH THE PRIMARY EXIT REGION OF A FAIRLY
WEAK LOW LEVEL JET AIMED NORTH OF THE LOCAL AREA NEAR THE NEB/SD
BORDER. AS A RESULT...GIVEN THE LACK OF NOTABLE THETA-E
ADVECTION/CONVERGENCE IN AND NEAR THE CWA AT BOTH THE 850/700MB
LEVEL...OUR CURRENTLY-ADVERTISED 50+ PERCENT POPS ACROSS THE
MAJORITY OF THE CWA OVERNIGHT ARE COMING INCREASINGLY UNDER
QUESTION ESPECIALLY IN THE CENTRAL/SOUTHEAST COUNTIES. NOT
SURPRISINGLY...THE LATEST 00Z NAM AND HRRR ARE BOTH PRETTY PALTRY
WITH MEASURABLE RAIN POTENTIAL OVERNIGHT. BASED ON CURRENT RADAR
TRENDS...IT MAY VERY WELL END UP BEING THE CASE THAT THE BEST HOPE
FOR LEGITIMATE RAINFALL WILL HINGE ON HOW SUCCESSFULLY THE
ACTIVITY CURRENTLY DRIFTING TOWARD THE FAR NORTHWEST EDGES OF THE
CWA HOLDS TOGETHER OVER THE NEXT FEW HOURS. PER THE LATEST RAP
INSTABILITY TRENDS...THERE COULD BE AT LEAST A MODEST INCREASE IN
ELEVATED MUCAPE IN THE 850-700MB LAYER INTO THE 500-1000 J/KG
RANGE AS THE NIGHT WEARS ON...BUT MODEL SOUNDINGS SHOW THAT EVEN
MUCH OF THIS INSTABILITY MAY BE RATHER CAPPED. AS FOR ANY
OVERNIGHT SEVERE THREAT...THAT ALSO APPEARS TO BE ON A
DECLINE...UNLESS SOMEHOW THE CONVECTION CURRENTLY IN THE NORTH
PLATTE CWA RE-INTENSIFIES OR DEVELOPS A NEW VIGOROUS COLD POOL
OVER THE NEXT FEW HOURS. HAIL-WISE...IT MAY BE TOUGH TO GET
ANYTHING LARGER THAN DIMES-NICKELS GIVEN LATEST INSTABILITY
TRENDS.
IN SUMMARY...WILL CONTINUE TO EXAMINE THE LATEST TRENDS AND
POTENTIALLY DECREASE POPS ACROSS PARTS OF THE CWA IN A FORTHCOMING
EVENING UPDATE...BUT IN THE CONTINUED PRESENCE OF SUBTLE
NORTHWEST-FLOW FORCING...PROBABLY CANNOT EXCLUDE ANY LOCATION FROM
AT LEAST A TOKEN 20 PERCENT CHANCE OF SHOWERS/STORMS
OVERNIGHT...AS NORTHWEST FLOW IS NOTORIOUS FOR PROVIDING A FEW
SURPRISES. BY AND LARGE THOUGH...ITS STARTING TO LOOK LIKE THE 50+
POPS WE/VE BEEN ADVERTISING THE PAST FEW DAYS MAY PROVE OVERDONE
FOR A DECENT CHUNK OF THE AREA...ESPECIALLY FOR THOSE LOOKING FOR
MORE THAN A FEW TENTHS OF AN INCH. ALSO MAY BE MAKING A FEW
DOWNWARD TWEAKS TO OVERNIGHT LOW TEMPS BASED ON LATEST
OBSERVATIONAL TRENDS AND GUIDANCE. WILL BE DEFER TO ONCOMING
OVERNIGHT SHIFT TO MAKE CHANGES BEYOND 12Z SUNDAY MORNING...BUT IT
APPEARS IT COULD BE ANOTHER DAY/NIGHT OF FICKLE THUNDERSTORM
TRENDS. LOOK FOR NEXT ROUND OF FORECAST UPDATES TO BE OUT BETWEEN
10-1030 PM...
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 353 PM CDT SAT JUL 20 2013
ALOFT: QUASI-ZONAL WNW FLOW WILL CONT THRU 00Z/MON. WV IMAGERY SHOWS
A SUBTLE SHRTWV TROF MOVING INTO THE PANHANDLE FROM WY. THIS TROF IS
FCST TO DEEPEN TNGT...CROSS THE FCST AREA SUN MRNG...AND WILL BE
MOVING INTO NERN KS DURING PEAK HEATING. WHILE THIS TROF MAY AID
TSTM DEVELOPMENT TNGT...HAVE TO WONDER IF SUBSIDENCE IN ITS WAKE
WILL CAP OFF TSTM THREAT SUN AFTN.
SFC: NUMEROUS OUTFLOW BOUNDARIES WILL LINGER THRU SUN. THE LEE/HEAT
LOW WILL STRENGTHEN AND DRIFT INTO WRN KS. THIS SHOULD DROP DWPTS
SUBSTANTIALLY FROM MCK-PHG-RCP AND PROBABLY DID NOT GO LOW ENOUGH.
RAINFALL: PLEASE FOLLOW OUR LOCAL STORM REPORTS /LSR/. WE HAVE
SEEN SOME SUBSTANTIAL 2-3 INCH AMTS BUT IT HAS BEEN FEAST OR
FAMINE.
REST OF THIS AFTN: THE ATMS HAS APPARENTLY STABILIZED OVER MUCH OF
S-CNTRL NEB BASED ON THE LACK OF CU AND A WWD MOVING OUTFLOW
BOUNDARY W OF HWY 283. SCT TSTMS WILL GRADUALLY DIE OFF OVER N-CNTRL
KS.
TNGT: PROBABLY SOMEWHAT OF A BREAK THIS EVNG. WE WERE WATCHING
UPSTREAM TSTMS OVER THE PANHANDLE...WHICH THE MODELS SUGGESTED WOULD
PROPAGATE INTO S-CNTRL NEB. THOSE TSTMS HAVE DIED WHICH LOWERS
CONFIDENCE IN TNGT/S FCST...ESPECIALLY SINCE VIS SATPIX SHOW NO
AGITATED CU FIELDS.
SOME SEMBLANCE OF A COUPLED ULJ DEVELOPS TNGT...WHICH WILL ENHANCE
THE LLJ. SO THE ENVIRONMENT WILL REMAIN FAVORABLE FOR ADDITIONAL
TSTM DEVELOPMENT.
SUN: IT ALL HINGES ON WHAT HAPPENS TNGT. IF SCT TSTMS FORM AND MOVE
THRU THEN WE/LL SEE TSTMS DEPARTING DURING THE MRNG HRS WITH
CLEARING THEREAFTER.
FCST SOUNDINGS INDICATE DAYTIME HEATING SHOULD ERODE THE CAP.
LEFTOVER OUTFLOW BOUNDARIES WILL PROVIDE FOCI FOR TSTM DEVELOPMENT.
HOWEVER...IT APPEARS DOUBTFUL WE SEE ANYTHING MORE THAN AN ISOLATED
TSTM MAYBE TWO? LARGE-SCALE SUBSIDENCE COULD LIMIT OR MITIGATE THE
THREAT ALTOGETHER. IT/S POSSIBLE MODEL SOUNDINGS ARE NOT FULLY
DEPICTING THIS. QPF IS PRETTY MEAGER SO IT MAY BE OF LITTLE
CONSEQUENCE.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 353 PM CDT SAT JUL 20 2013
GUIDANCE SUGGESTS NORTHWESTERLY MID TO UPPER LEVEL FLOW WILL PERSIST
OVER THE CENTRAL PLAINS THROUGH MUCH OF THE EXTENDED FORECAST
PERIOD. THERE WILL BE THE POTENTIAL FOR MULTIPLE SMALL SCALE
PERTURBATIONS TO WORK THEIR WAY ACROSS THE REGION AS A RESULT...WITH
QPF FIELDS FROM THE NAM...OPERATIONAL GFS...EC AND SREF-MEAN
SUGGESTING PRECIPITATION WILL BE REALIZED OVER VARIOUS PORTIONS OF
OUR AREA DURING THE EXTENDED FORECAST PERIOD. AN EVEN AVERAGE OF THE
NAM...OPERATIONAL GFS...EC...AND SREF-MEAN WAS UTILIZED TO DERIVE
QPF FIELDS AND RESULTANT POPS FOR MONDAY AND TUESDAY...WHICH RESULTS
IN LOW POPS BEING PRESENTED TO MOST ALL OF THE CWA BOTH DAYS. THE
SAME PATTERN IS EXPECTED TO PERSIST THROUGH MUCH OF THE REST OF THE
WEEK AS WELL...WITH ALLBLEND PROVIDING 20-60% POPS TO THE CWA AS A
RESULT. THESE POPS WERE LEFT UNCHANGED FOR THE MOST PART.
AS FOR SEVERE WEATHER CHANCES DURING THE EXTENDED FORECAST
PERIOD...PERSISTENT LOW LEVEL MOISTURE SHOULD PRESENT DECENT CAPE
VALUES ACROSS THE AREA...WITH GUIDANCE SUGGESTING SUCH VALUES WILL
AVERAGE FROM 1500 TO 3000J/KG ON MOST DAYS. GIVEN THE UNCERTAINTY OF
PLACEMENT AND TIMING OF SEVERE WEATHER HOWEVER...WILL PROVIDE A
VAGUE SEVERE WEATHER MENTION IN THE HWO FOR MONDAY BUT LEAVE OUT ANY
MENTION OF SEVERE WEATHER THROUGH THE REMAINDER OF THE EXTENDED
FORECAST PERIOD.
LITTLE CHANGE IN THE LOW LEVEL AIRMASS SHOULD PRESENT AFTERNOON HIGH
TEMPERATURES IN THE 90S TO START THE EXTENDED FORECAST PERIOD...WITH
SLIGHTLY COOLER AIR PROVIDING AFTERNOON HIGHS IN THE 80S TO NEAR 90
BY THE END OF THE EXTENDED FORECAST PERIOD. OVERNIGHT LOW
TEMPERATURES IN THE 60S ARE EXPECTED FOR MOST PART DURING THE
EXTENDED FORECAST PERIOD.
&&
.AVIATION...(FOR THE 00Z KGRI TAF THROUGH 00Z SUNDAY EVENING)
ISSUED AT 653 PM CDT SAT JUL 20 2013
AT LEAST FOR THE TIME BEING...WILL MAINTAIN VFR CEILING/VISIBILITY
AND FAIRLY LIGHT BREEZES THROUGHOUT THE NEXT 24 HOURS...BUT PLEASE
NOTE THIS DOES NOT TAKE INTO ACCOUNT THE STILL-TOO-SOON-TO-RESOLVE
EFFECTS THAT THUNDERSTORMS COULD HAVE ON THE TERMINAL. AS FOR
THESE STORM CHANCES...WILL CONTINUE TO CARRY A VICINITY
THUNDERSTORM MENTION DURING A 7-HOUR BLOCK FROM 04Z-11Z
TONIGHT...AS THIS APPEARED TO BE THE MOST FAVORED WINDOW OF
OPPORTUNITY. SHOULD STORMS MOVING GENERALLY TOWARD THE AREA FROM
NORTHWEST NEBRASKA MAINTAIN A CONSISTENT TRACK OVER THE NEXT
SEVERAL HOURS...ITS QUITE POSSIBLE THAT A MORE-REFINED TEMPO GROUP
MAY BE INTRODUCED LATER THIS EVENING. SHOULD STORMS MOVE IN
LATER...AT LEAST A BRIEF PERIOD OF HEAVY RAIN AND GUSTS IN EXCESS
OF 30-40KT CANNOT BE RULED OUT. BEYOND 11Z SUNDAY MORNING...WILL
KEEP THE FORECAST VOID OF THUNDERSTORM MENTION...BUT ITS NOT OUT
OF THE QUESTION THAT ADDITIONAL STORM CHANCES COULD CREEP BACK
INTO THE PICTURE MAINLY LATE SUNDAY AFTERNOON...BUT CONFIDENCE IS
FAR TOO LOW TO INTRODUCE THIS INTO THE FORECAST YET. SHOULD RAIN
HAPPEN TO FALL AT KGRI LATER TONIGHT...THE COMBINATION OF WET
GROUND AND GENERALLY LIGHT/VARIABLE BREEZES COULD RESULT IN AT
LEAST LIGHT FOG/MVFR VISIBILITY RESTRICTIONS...BUT AGAIN WITH SO
MUCH UNCERTAINTY IN STORM TIMING IN THE FIRST PLACE...WILL
ACKNOWLEDGE FOG AS A LOW PROBABILITY CAVEAT FOR NOW...AND NOT
INSERT INTO THE TAF.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...PFANNKUCH
SHORT TERM...HALBLAUB
LONG TERM...BRYANT
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
637 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 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 635 PM CDT SAT JUL 20 2013
THUNDERSTORMS WILL SWEEP THE FORECAST AREA TONIGHT...AND EXIT BY 09Z.
VFR IS EXPECTED THEREAFTER UNTIL 21Z SUNDAY AT WHICH TIME ISOLATED
THUNDERSTORMS COULD REDEVELOP...WEST OF HIGHWAY 83.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CLB
SHORT TERM...SPRINGER
LONG TERM...CLB
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
550 AM CDT FRI JUL 19 2013
.UPDATE...
ISSUED AT 541 AM CDT FRI JUL 19 2013
CONVECTION HAS DEVELOPED ACROSS PLATTE AND NANCE COUNTY AND MAY
CONTINUE TO EXPAND ACROSS OUR NORTHERN CWA OVER THE NEXT FEW HOURS
IF THE HRRR IS ACCURATE. THE HRRR SEEMS TO HAVE THE BEST HANDLE ON
THIS SITUATION AND WILL BE SENDING OUT AN UPDATED FORECAST SHORTLY
TO INCLUDE THUNDERSTORMS THIS MORNING ACROSS NORTHERN ZONES.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 339 AM CDT FRI JUL 19 2013
HOT CONDITIONS WILL PERSIST TODAY...BUT AT LEAST THERE IS FINALLY
A SLIGHT CHANCE OF PRECIPITATION ACROSS PORTIONS OF THE FORECAST
AREA.
A FRONTAL BOUNDARY LOCATED OVER NORTHERN NEBRASKA EARLY THIS
MORNING WILL SLIDE SOUTH AND INTO NORTHERN KANSAS BY LATER THIS
AFTERNOON. THE AIR ALONG AND RIGHT BEHIND THIS FRONT REMAINS HOT
AND THUS DO NOT EXPECT ANY RELIEF FROM THE HEAT TODAY. IN
FACT...THE WIND WILL BECOME RATHER LIGHT IN CLOSE PROXIMITY TO THE
FRONT AND MOISTURE WILL POOL ALONG THE FRONT MAKING FOR A MORE
UNCOMFORTABLE STICKY DAY WITH LESS AIR FLOW TO KEEP YOU COOL.
THERE SHOULD BE A FEW MORE CLOUDS THAN THE PAST SEVERAL DAYS GIVEN
CONVERGENCE ALONG THE FRONT. THE EARLY MORNING RUNS OF THE HRRR
WOULD INDICATE THE POTENTIAL FOR SHOWERS THIS MORNING...BUT MOST
FORECAST MODELS HOLD OFF PRECIPITATION UNTIL AFTERNOON. THE HRRR
HAS BEEN OVERDOING PRECIPITATION THIS MORNING THUS FAR BASED ON
THE LACK OF RADAR ECHOS. HENCE WILL KEEP ACCUMULATING
PRECIPITATION OUT OF THE FORECAST UNTIL AFTERNOON...BUT CAN NOT
COMPLETELY RULE OUT SPRINKLES OR A VERY LIGHT SHOWER THIS
MORNING NEAR THE SFC FRONT.
TONIGHT...THE SFC FRONT WILL BE LOCATED OVER NORTHER KANSAS AND
THIS IS WHERE OUR BEST CHANCE OF RAIN WILL BE...ALTHOUGH IT IS
ONLY A SLIGHT CHANCE OF PRECIPITATION. WILL ALSO NEED TO KEEP AN
EYE OUT TO THE NORTHWEST AS SHOWERS AND THUNDERSTORMS FROM
SOUTHWEST SOUTH DAKOTA AND WESTERN NEBRASKA TRY TO MAKE IT INTO
OUR NORTHERN MOST TIER OF COUNTIES AS WE NEAR DAWN. CURRENT
THINKING BASED ON MOST FORECAST MODELS IS THAT THE NORTHERN
CONVECTION WILL REMAIN NORTH OF OUR FORECAST AREA...BUT WORTH
KEEPING AN EYE ON.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 339 AM CDT FRI JUL 19 2013
MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS AND
TEMPERATURES.
NORTHWEST FLOW IS FORECAST TO REMAIN ACROSS THE PLAINS THROUGH THIS
PERIOD. THERE ARE SEVERAL UPPER LEVEL WAVES THAT MOVE THROUGH THE
NORTHWEST FLOW AND EACH OF THEM BRING ANOTHER CHANCE FOR SHOWERS AND
THUNDERSTORMS TO THE AREA. AS IS TYPICAL OF THIS TYPE OF REGIME THE
TIMING AND STRENGTH OF THESE WAVES PLAYS A LARGE PART IN WHERE
PRECIPITATION WILL FALL. MODELS HAVE SLIGHTLY DIFFERENT TIMING OF
THESE WAVES AS THEY MOVE THROUGH THE AREA. THIS GIVES THE RELATIVELY
SMALL POPS FOR NEARLY EVERY PERIOD FOR AT LEAST A PORTION OF THE
AREA.
AT THIS TIME THE STRONGEST AND MOST LIKELY PERIOD FOR THERE TO BE
SOME PRECIPITATION WILL BE DURING THE SATURDAY NIGHT THROUGH SUNDAY
NIGHT TIME FRAME. AN UPPER LEVEL WAVE MOVES INTO THE AREA SATURDAY
AND STRENGTHENS SATURDAY NIGHT. AS THE UPPER WAVE MOVES INTO THE
AREA SATURDAY MORNING THERE IS A CHANCE FOR SOME THUNDERSTORMS IN
THE NORTH...BUT THE MAIN THUNDERSTORMS ARE EXPECTED TO DEVELOP ON
THE HIGH PLAINS DURING THE AFTERNOON AND MOVE INTO THE AREA DURING
THE AFTERNOON AND EVENING. MUCAPE IS THE BEST DURING THE LATE
AFTERNOON INTO THE EVENING AND EXPECT THERE COULD BE SOME STRONG TO
SEVERE STORMS DURING THIS TIME. THE THUNDERSTORMS ARE EXPECTED TO
CONTINUE INTO SUNDAY AND SUNDAY NIGHT AS ANOTHER WAVE MOVES INTO THE
AREA.
THE SAME STORY CONTINUES TO PLAY OUT MONDAY THROUGH TUESDAY NIGHT AS
A SERIES OF UPPER LEVEL WAVES MOVE THROUGH. THESE ARE A LITTLE
WEAKER AND EXPECT THERE MAY BE SOME MORE SPOTTY PRECIPITATION OUT OF
THESE UPPER WAVES. NOT EVERYONE WILL HAVE PRECIPITATION AS THESE
SYSTEMS MOVE THROUGH. WEDNESDAY APPEARS TO BE DRY BEFORE MORE WEAK
UPPER LEVEL WAVES MOVE INTO THE AREA AND SOME SLIGHT CHANCES FOR
THUNDERSTORMS.
TEMPERATURES WILL BE AROUND NORMAL OR JUST A LITTLE ABOVE DURING
THIS TIME.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 541 AM CDT FRI JUL 19 2013
THERE ARE ESSENTIALLY TWO THINGS TO WATCH FOR. THE FIRST WILL BE A
GRADUALLY SHIFTING WIND AS A FRONT PASSES THROUGH. EXPECT A SHIFT
FROM SOUTHWEST...TO NORTH...TO NORTHEAST OVER THE COURSE OF THE
MORNING. THE SECOND AREA OF CONCERN WILL CENTER AROUND THE SLIGHT
CHANCE OF AN ISOLATED THUNDERSTORM. THE BEST CHANCE OF
THUNDERSTORMS WOULD BE FROM LATE MORNING THROUGH MID AFTERNOON.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...WESELY
SHORT TERM...WESELY
LONG TERM...JCB
AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS BUFFALO NY
348 PM EDT FRI JUL 19 2013
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS WILL DROP ACROSS THE REGION TONIGHT...WHICH
WILL LINGER INTO SATURDAY. A COLD FRONT WILL DROP ACROSS THE
REGION SATURDAY...BRINGING MUCH COOLER CONDITIONS FOR SUNDAY AND
INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
FOR THE REMAINDER OF THIS AFTERNOON HOT AND WINDY CONDITIONS WILL
PERSIST ACROSS THE REGION. AN UPPER LEVEL TROF SOUTH OF HUDSON BAY
WILL DIVE TOWARD THE UPPER LAKES THROUGH TONIGHT...PUSHING AN
ASSOCIATED COLD FRONTAL BOUNDARY TOWARD OUR REGION. WHILE THE
FRONT ITSELF WILL REMAIN WELL UPSTREAM...THIS WILL RESULT IN A
TIGHTENING PRESSURE GRADIENT. THE BUFFALO VAD WIND PROFILE
ALREADY SHOWS 40 KNOT WINDS AT 925 MB...WITH THESE WINDS FORECAST
TO INCREASE SLIGHTLY FROM WEST TO EAST THROUGH THIS EVENING.
THESE SOUTHWEST WINDS SHOULD FAIRLY READILY MIX TO THE
SURFACE...WITH THE LAKE BREEZE ENHANCING THIS FLOW TO THE
NORTHEAST OF THE LAKES. THE WINDIEST CONDITIONS SHOULD BE ACROSS
THE NIAGARA FRONTIER AND IMMEDIATE LAKE ERIE SHORELINE...WHICH
INCLUDES THE BUFFALO METRO AREA. GUSTS SHOULD GENERALLY RUN IN THE
40 TO 45 MPH RANGE IN THIS AREA...WITH PEAK GUSTS LIKELY TO TOP
OUT NEAR 50 MPH. EXPECT THAT WITH THE FULL FOLIAGE...THIS WILL
RESULT IN A FEW DOWNED TREE LIMBS...WITH SOME SPOTTY POWER OUTAGES
POSSIBLE. ELSEWHERE WILL BE BREEZY AS WELL...BUT INTERIOR
LOCATIONS WILL GENERALLY LESS WINDY.
THE OTHER BIG ISSUE WILL SIMPLY BE THE HOT WEATHER. THE SW FLOW
OFF THE LAKE SHOULD HOLD TEMPERATURES 90 IN THE BUFFALO
AREA...BUT ROCHESTER EASTWARD THIS FLOW WILL DOWNSLOPE AND ADD A
FEW MORE DEGREES TO THE ALREADY HOT WEATHER. FOR MANY THIS WILL BE
THE HOTTEST DAY SO FAR...WITH HIGHS IN THE MID 90S. THIS COMBINED
WITH DEW POINTS IN THE LOWER 70S WILL RESULT IN HEAT INDEX VALUES
OVER 100 FOR ROCHESTER AND IN THE NORTHERN GENESEE VALLEY AND
FINGER LAKES REGIONS. OTHERWISE...EXPECT WIDELY SCATTERED SHOWERS
AND THUNDERSTORMS ACROSS WESTERN PORTIONS OF THE SOUTHERN TIER AND
EASTERN LAKE ONTARIO REGION TO DISSIPATE TOWARD SUNSET...AS DAYTIME
HEATING DIMINISHES AND AS WINDS INCREASE MIXING AND EXPAND THE
LAKE SHADOWING.
FOR TONIGHT AND INTO SATURDAY...THE FOCUS WILL SHIFT TO THE
POTENTIAL FOR SEVERE WEATHER AND FOR LOCALLY HEAVY RAINFALL. THIS WILL
LIKELY COME IN TWO WAVES. THE FIRST CAN ALREADY BE SEEN CLEARLY
THROUGH MID-AFTERNOON...WITH THIS AREA ASSOCIATED WITH A LINE OF
THUNDERSTORMS ACROSS LAKE HURON AND EXTENDING EAST INTO SOUTHERN
ONTARIO PROVINCE. THIS INITIAL WAVE WILL TRACK TOWARD OUR REGION...BUT
GIVEN THE STRONG SW FLOW ACROSS THE LAKES WILL PROBABLY CAUSE IT TO
WEAKEN AS IT TRIES TO MOVE INTO OUR REGION. HIGHER RESOLUTION
GUIDANCE IS IN GENERAL AGREEMENT WITH THE NAM/RGEM/HRRR ALL
SHOWING THIS GENERAL TREND. THERE IS STILL A POSSIBILITY THAT THIS
WILL HOLD TOGETHER LONG ENOUGH TO HAVE SOME IMPACT ON OUR
CWA...WITH THE SAINT LAWRENCE RIVER AND NORTH COUNTRY AND POSSIBLY
PORTIONS OF THE NIAGARA FRONTIER THE AREAS TO WATCH. IT WILL BE
TRICKY...SINCE THE LINE WILL PROBABLY BE QUITE IMPRESSIVE JUST
UPSTREAM OF THE LAKE BREEZE...WITH BOWING LINE SEGMENTS CAPABLE OF
PRODUCING DAMAGING WINDS. THIS INITIAL LINE WILL IMPACT OUR
REGION BETWEEN 700 PM AND 1000 PM.
BEHIND THIS...IS A SECONDARY LINE OF THUNDERSTORMS DEVELOPING
ALONG WHAT APPEARS TO BE A PRE-FRONTAL TROF WIND SHIFT BOUNDARY.
00/12Z RUNS OF THE NAM/RGEM AND RECENT RUNS OF THE HRRR CONTINUE
TO SUGGEST THAT THIS AREA WILL EXPAND...AND EVENTUALLY DROP ACROSS
OUR REGION DURING THE OVERNIGHT HOURS. THE LATER TIMING...AND
CLOSER PROXIMITY TO THE SHORTWAVE WILL MAKE THIS FEATURE MORE
LIKELY TO HOLD TOGETHER AS IT DROPS ACROSS THE LAKES AND ACROSS
WESTERN NEW YORK LATE TONIGHT AND INTO SATURDAY MORNING. THIS
TIMING IS CLIMATOLOGICALLY NOT FAVORABLE FOR SEVERE WEATHER...BUT
GIVEN THE SIGNIFICANT AMOUNT OF NIGHTTIME INSTABILITY...AND STILL
A FAIR AMOUNT OF SHEAR...IT WILL BEAR A RADAR WATCH IF IT DOES
INDEED DEVELOP AS FORECAST.
IN ADDITION TO THE SEVERE WEATHER THREAT...THERE WILL ALSO BE A
RISK FOR LOCALLY HEAVY DOWNPOURS. PRECIPITABLE WATER VALUES WILL
BE 1.75 TO 2.00 INCHES...AND WHILE STORMS WILL LIKELY BE
MOVING...LARGE AREAS OF CONVECTION OR BRIEF TRAINING COULD QUICKLY
ADD UP AND LEAD TO LOCALIZED FLOODING.
ON SATURDAY...EXPECT MOST OF THE SHOWERS AND THUNDERSTORM ACTIVITY
TO SLIDE TO THE SOUTH AND EAST OF THE AREA LATE MORNING AND INTO
THE AFTERNOON HOURS. THE ACTUAL FRONTAL BOUNDARY WILL NOT CROSS
UNTIL LATER IN THE DAY...BUT MUCH DRIER AIR WILL MOVE IN BEHIND
THE PRE-FRONTAL TROF WITH ONLY MARGINAL CHANCE FOR ANY SHOWERS OR
THUNDERSTORMS ALONG THE FRONT ITSELF WHICH WILL CROSS LATE IN THE
DAY SATURDAY. WITH COOLER AIR MOVING IN AND LINGERING
PRECIPITATION...TEMPERATURES WILL BE NOTABLY COOLER ON
SATURDAY...WITH HIGHS MAINLY IN THE LOWER 80S.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
BY SATURDAY EVENING...MOST OF THE 12Z GUIDANCE PACKAGES ARE IN GOOD
AGREEMENT THAT THE COLD FRONTAL ZONE AND THE BULK OF ITS ASSOCIATED
PRECIPITATION WILL HAVE SLIPPED TO OUR SOUTH...SAVE FOR THE NAM
WHICH IS A SLOWER OUTLIER. AS THIS PARTICULAR MODEL HAS SHOWN SOME
RUN-TO-RUN INCONSISTENCIES WITH THE TIMING OF THE FRONT OVER THE
PAST DAY OR SO...WILL DISREGARD IT IN FAVOR OF THE FASTER GFS/
GEM/ECMWF CONSENSUS AND OUR EXISTING CONTINUITY...ALL OF WHICH
ADVERTISE A GENERALLY DRY NIGHT. IN THE WAKE OF THE FRONT...A HIGHLY
ANTICIPATED COOLER AND DRIER AIRMASS WILL SPREAD SOUTH ACROSS OUR
AREA THROUGH THE COURSE OF THE NIGHT...FINALLY BRINGING SOME MUCH
WELCOMED RELIEF FROM THE TROPICAL HEAT AND HUMIDITY LEVELS OF THE
PAST WEEK. EXPECT OVERNIGHT LOWS TO DROP TO THE MID 50S TO LOWER
60S...WHILE SURFACE DEWPOINTS FALL BACK TO MUCH MORE COMFORTABLE
LEVELS IN THE 50S.
WITH THE WATERS OF THE LOWER GREAT LAKES NOW IN THE MID TO UPPER 70S
/OR AROUND +25C/...AND THE INCOMING COOLER AIRMASS EVENTUALLY
FEATURING 850 MB TEMPS OF AROUND +10C BY LATER IN THE NIGHT...WE MAY
WELL SEE SOME LAKE EFFECT CLOUDINESS DEVELOP SOUTH OF THE LAKES
OVERNIGHT...THOUGH THE INCOMING AIRMASS WILL LIKELY REMAIN TOO DRY
AND FEATURE TOO LOW OF A SUBSIDENCE INVERSION TO SUPPORT ANY LAKE
EFFECT SHOWERS.
SUNDAY AND SUNDAY NIGHT...SURFACE HIGH PRESSURE WILL SETTLE DIRECTLY
ACROSS THE LOWER LAKES AND NEW YORK STATE IN THE WAKE OF THE COLD
FRONT. COUPLED WITH STRONG MIDSUMMER DIURNAL EFFECTS...THIS SHOULD
RESULT IN ANY LAKE EFFECT CLOUDS FROM SATURDAY NIGHT BREAKING UP
DURING THE COURSE OF SUNDAY MORNING...LEADING TO A DECENT AMOUNT OF
SUNSHINE EVERYWHERE FOR THE AFTERNOON. MEANWHILE...850 MB TEMPS
RANGING FROM +9C NORTH TO +13C SOUTH SHOULD SUPPORT RATHER PLEASANT
HIGHS IN THE MID TO UPPER 70S...WHILE DEWPOINTS CONTINUE TO LOWER TO
THE 50-55 DEGREE RANGE WITH DIURNAL MIXING. THE COOLER AND QUIET
WEATHER WILL THEN CONTINUE INTO SUNDAY NIGHT...WHEN LOWS SHOULD
RANGE THROUGH THE 50S IN MOST LOCATIONS...WITH SOME UPPER 40S EVEN
POSSIBLE ACROSS PORTIONS OF THE NORTH COUNTRY. WITH THE LOW LEVEL
FLOW VEERING MORE EASTERLY...DO NOT EXPECT LAKE EFFECT CLOUDINESS TO
BE A PROBLEM FOR SUNDAY NIGHT...THOUGH THERE WILL PROBABLY BE SOME
INCREASE IN MID/HIGH CLOUDS OVERNIGHT IN ADVANCE OF A MODEST
SHORTWAVE TROUGH THAT WILL BE WORKING INTO THE CENTRAL GREAT LAKES.
MONDAY AND MONDAY NIGHT...THE SURFACE HIGH WILL SLIDE EAST ACROSS
NEW ENGLAND AND OUT TO SEA...WHILE THE AFOREMENTIONED SHORTWAVE
TROUGH TO OUR WEST SETTLES ACROSS THE LOWER LAKES AND NY/PA...WHILE
ALSO SPAWNING SOME SEMBLANCE OF A WEAK SURFACE REFLECTION. WHILE THE
VARIOUS GUIDANCE PACKAGES STILL DIFFER WITH RESPECT TO HOW FAST
THIS SYSTEM ARRIVES AND EXACTLY HOW WELL DEVELOPED IT WILL BE...ALL
HAVE CONTINUED THE RECENT TREND TOWARD A FASTER AND SOMEWHAT MORE
DEVELOPED SYSTEM...WITH A PLUME OF DEEPER MOISTURE AND WEAK TO
MODEST ISENTROPIC LIFT EVENTUALLY ADVECTING INTO OUR AREA BETWEEN
MONDAY AFTERNOON AND MONDAY NIGHT. WITH THIS AND OUR EXISTING
CONTINUITY OF A TOTALLY DRY FORECAST BOTH IN MIND...HAVE ELECTED TO
GRADUALLY INTRODUCE SOME LOWER CHANCE POPS INTO AREAS SOUTH OF LAKE
ONTARIO MONDAY AFTERNOON...BEFORE BRINGING HIGHER CHANCE RANGE POPS
INTO THE ENTIRE AREA MONDAY NIGHT. THE HIGHEST PRECIPITATION CHANCES
WILL BE FOCUSED ACROSS OUR FINGER LAKES AND NORTH COUNTRY ZONES...
WHICH WILL BE CLOSEST TO THE BEST AREA OF DEEPER MOISTURE AND
ISENTROPIC LIFT. TEMPS THROUGH THIS LATTER PORTION OF THE PERIOD
WILL RETURN TO MIDSUMMER NORMS GIVEN THE WEAK WARM AIR ADVECTION
PATTERN...WITH DAYTIME HIGHS OF AROUND 80 EXPECTED ON MONDAY...
FOLLOWED BY LOWS IN THE LOWER TO MID 60S MONDAY NIGHT.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
IN THE LONG TERM PORTION OF THE FORECAST...THE LARGE-SCALE WEATHER
PATTERN ACROSS NORTH AMERICA WILL REVERT TO ONE WE HAVE BEEN MORE
FAMILIAR WITH FOR THE BULK OF THE SPRING AND SUMMER...THAT OF A
BROAD RIDGE OVER THE ROCKIES AND WESTERN PLAINS...WITH A
CORRESPONDING BROAD DOWNSTREAM TROUGH DEVELOPING OVER THE GREAT
LAKES AND NORTHEAST. THIS CHANGE IN THE PATTERN WILL RESULT IN AN
EXTENDED PERIOD OF MORE NORMAL SUMMERTIME TEMPERATURES FOR OUR
REGION...WITH DAILY HIGHS AVERAGING WITHIN A FEW DEGREES OF 80 EACH
DAY...AND NIGHTTIME LOWS GENERALLY RANGING IN THE LOWER TO MID 60S.
WITH RESPECT TO PRECIPITATION CHANCES...THE FORECAST PICTURE REMAINS
CONSIDERABLY MORE MUDDLED. UNDER THE EXPECTED LARGE-SCALE FLOW
REGIME...NUMEROUS PIECES OF SHORTWAVE ENERGY SHOULD ROTATE THROUGH
THE DEVELOPING TROUGH AND LEAD TO PERIODIC CHANCES FOR SHOWERS AND
THUNDERSTORMS...HOWEVER THE MEDIUM RANGE GUIDANCE REMAINS ALL OVER
THE MAP WITH RESPECT TO THE TIMING AND STRENGTH OF THESE FEATURES.
WITH THIS IN MIND...HAVE JUST CONTINUED TO BROADBRUSH SOME LOW
CHANCE POPS ACROSS THE ENTIRE PERIOD FOR NOW...AND WILL WAIT UNTIL
BETTER MODEL AGREEMENT DEVELOPS BEFORE TRYING TO PROVIDE MORE
REFINED/DETAILED PRECIPITATION PROBABILITIES AND TIMING. ALL THIS
SAID...THIS PERIOD LOOKS TO BE FAR FROM A WASHOUT AT THIS TIME...
WITH ANY SHOTS OF SHOWERS/STORMS LIKELY TO ALTERNATE WITH FREQUENT
DRY PERIODS.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
FOR THE 18Z TAF CYCLE...GUSTY SW WINDS TO BE THE MAIN IMPACT FOR
THIS AFTERNOON...WITH BUF/IAG/ROC/ART ALL SEEING PREVAILING GUSTS
IN THE 30 TO 35 KT RANGE. WIDELY SCATTERED THUNDERSTORMS MAY
BRIEFLY IMPACT JHW.
AFTER THIS...A LINE OF THUNDERSTORMS WILL APPROACH FROM THE WEST
23Z. THIS AREA WILL PROBABLY WEAKEN AS IT MOVES INTO OUR
REGION...BUT MAY HOLD TOGETHER LONG ENOUGH TO IMPACT IAG/ART...AND
POSSIBLY BUF/ROC DURING THE EVENING HOURS. STEADIER THUNDERSTORMS
ARE LIKELY LATE TONIGHT AS A LARGER AREA IS FORECAST TO DROP
ACROSS THE REGION. ALL THUNDERSTORMS MAY CONTAIN GUSTY WINDS AND
WIND SHIFTS...WITH HEAVY RAIN LOWERING VSBY TO 1SM.
STORMS WILL DROP FROM N-S LATE TONIGHT AND INTO SATURDAY
MORNING...WITH CONDITIONS IMPROVING TO VFR.
OUTLOOK...
SATURDAY NIGHT THROUGH MONDAY MORNING...VFR.
MONDAY AFTERNOON THROUGH WEDNESDAY...MAINLY VFR WITH A CHANCE OF
SHOWERS/THUNDERSTORMS.
&&
.MARINE...
WINDS HAVE PICKED UP THROUGH THE EARLY AFTERNOON HOURS ACROSS MOST
OF THE WATERS...WITH WINDS STRONGEST NEAR THE LAKE SHORES. THESE
WILL CONTINUE THROUGH THIS EVENING...AS A STRONG LOW LEVEL JET
REMAINS ACROSS THE REGION. WINDS WILL DIMINISH FROM WEST TO EAST
LATER TONIGHT...MORE QUICKLY ACROSS AREAS NEAR LAND WHERE THE LOSS
OF DAYTIME HEATING WILL RESULT IN LESS MIXING. WAVES ON THE
NORTHEAST SHORES WILL TAKE A BIT TO DROP OFF ON BOTH OF THE LAKES.
THE OTHER ISSUE FOR THIS EVENING AND TONIGHT WILL BE THE POTENTIAL
FOR STRONG TO SEVERE THUNDERSTORMS ON THE WATERS.
WINDS WILL DIMINISH SATURDAY AND ONWARD WITH NO HEADLINES ANTICIPATED.
&&
.CLIMATE...
HOT AND HUMID WEATHER WILL CONTINUE THROUGH TODAY AND TEMPERATURES
WILL APPROACH RECORD HIGHS THIS AFTERNOON...THOUGH THE ONLY SITE
THAT IS EXPECTED TO AT LEAST TIE IT/S RECORD HIGH IS ROCHESTER.
HOWEVER...WITH READINGS IN THE UPPER 70S THIS FRIDAY MORNING...RECORD
WARM LOWS SHOULD BE BROKEN AT ALL THREE LOCATIONS BELOW.
HERE ARE THE RECORDS FOR THE REMAINDER OF THE WORK WEEK.
BUFFALO..
DATE RECORD HIGH RECORD WARM LOW
FRI 7/19 92 75
ROCHESTER..
DATE RECORD HIGH RECORD WARM LOW
FRI 7/19 95 75
WATERTOWN..
DATE RECORD HIGH RECORD WARM LOW
FRI 7/19 92 72
HERE ARE THE MONTHLY AND ALL TIME RECORD LOW MINIMUMS...
BUFFALO..
JULY.. 78 1897
ALL TIME.. 79 2006
ROCHESTER..
JULY (ALL TIME)..81 1936 AND 1940
WATERTOWN..
JULY (ALL TIME).. 79 2011
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ001>006-011-
013-014.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ001-002-010-
011-019-085.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR LEZ020.
SMALL CRAFT ADVISORY UNTIL 10 AM EDT SATURDAY FOR LEZ040-
041.
SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR
LOZ030-042-043.
SMALL CRAFT ADVISORY UNTIL 10 AM EDT SATURDAY FOR LOZ044-
045.
SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR
SLZ022-024.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...JJR
LONG TERM...JJR
AVIATION...APFFEL
MARINE...APFFEL
CLIMATE...HITCHCOCK/WOOD/THOMAS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
302 PM EDT FRI JUL 19 2013
.SYNOPSIS...
HOT AND HUMID CONDITIONS WILL PERSIST FOR ONE MORE DAY...WITH PLENTY
OF SUNSHINE AND MAINLY RAIN FREE CONDITIONS TODAY. THERE WILL BE JUST
AN ISOLATED STORM WELL INLAND FROM THE LAKES THIS AFTERNOON. THERE
WILL ALSO BE A GUSTY SOUTHWESTERLY WIND TODAY AHEAD OF A COLD
FRONT...WITH THE COLD FRONT BRINGING SOME SHOWERS AND THUNDERSTORMS
FRIDAY NIGHT INTO SATURDAY ACROSS THE REGION. COMFORTABLE CONDITIONS
WILL FINALLY RETURN BEHIND THE FRONT FOR SUNDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
FOR THE REMAINDER OF THIS AFTERNOON HOT AND WINDY CONDITIONS WILL
PERSIST ACROSS THE REGION. AN UPPER LEVEL TROF SOUTH OF HUDSON BAY
WILL DIVE TOWARD THE UPPER LAKES THROUGH TONIGHT...PUSHING AN
ASSOCIATED COLD FRONTAL BOUNDARY TOWARD OUR REGION. WHILE THE
FRONT ITSELF WILL REMAIN WELL UPSTREAM...THIS WILL RESULT IN A
TIGHTENING PRESSURE GRADIENT. THE VAD WIND PROFILE ALREADY SHOWS
40 KNOT WINDS AT 925 MB...AND THESE ARE FORECAST TO INCREASE A BIT
MORE THROUGH SUNSET FROM WEST TO EAST. THESE SOUTHWEST WINDS
SHOULD FAIRLY READILY MIX TO THE SURFACE...WITH THE LAKE BREEZE
ENHANCING THIS FLOW TO THE NORTHEAST OF THE LAKES. THE WINDIEST
CONDITIONS SHOULD BE ACROSS THE NIAGARA FRONTIER AND IMMEDIATE LAKE
ERIE SHORELINE...WHICH INCLUDES THE BUFFALO METRO AREA. GUSTS
SHOULD GENERALLY RUN IN THE 40 TO 45 MPH RANGE IN THIS AREA...WITH
PEAK GUSTS LIKELY TO TOP OUT NEAR 50 MPH. EXPECT THAT WITH THE
FULL FOLIAGE...THIS WILL RESULT IN A FEW DOWNED TREE LIMBS...WITH
SOME SPOTTY POWER OUTAGES POSSIBLE. ELSEWHERE WILL BE BREEZY AS
WELL...BUT INTERIOR LOCATIONS WILL GENERALLY LESS WINDY.
THE OTHER BIG ISSUE WILL SIMPLY BE THE HOT WEATHER. THE SW FLOW
OFF THE LAKE SHOULD HOLD TEMPERATURES 90 IN THE BUFFALO
AREA...BUT ROCHESTER EASTWARD THIS FLOW WILL DOWNSLOPE AND ADD A
FEW MORE DEGREES TO THE ALREADY HOT WEATHER. FOR MANY THIS WILL BE
THE HOTTEST DAY SO FAR...WITH HIGHS IN THE MID 90S. THIS COMBINED
WITH DEW POINTS IN THE LOWER 70S WILL RESULT IN HEAT INDEX VALUES
OVER 100 FOR ROCHESTER AND IN THE NORTHERN GENESEE VALLEY AND
FINGER LAKES REGIONS. OTHERWISE...EXPECT SCATTERED SHOWERS AND
THUNDERSTORMS ACROSS WESTERN PORTIONS OF THE SOUTHERN TIER AND
EASTERN LAKE ONTARIO REGION TO DISSIPATE TOWARD THIS EVENING...AS
DAYTIME HEATING DIMINISHES AND AS WINDS INCREASE MIXING AND EXPAND
THE LAKE SHADOWING.
FOR TONIGHT AND INTO SATURDAY...THE FOCUS WILL SHIFT TO THE
POTENTIAL FOR SEVERE WEATHER...WITH LOCALLY HEAVY DOWNPOURS. THIS
WILL LIKELY COME IN TWO WAVES. THE FIRST CAN ALREADY BE SEEN
CLEARLY EARLY THIS AFTERNOON...ASSOCIATED WITH A LINE OF
THUNDERSTORMS DEVELOPING ACROSS CENTRAL MICHIGAN TO LAKE HURON.
THIS INITIAL WAVE WILL TRACK TOWARD OUR REGION THROUGH THE
AFTERNOON HOURS...BUT GIVEN THE STRONG SW FLOW ACROSS THE LAKES
EXPECT IT WILL WEAKEN RAPIDLY AS IT APPROACHES OUR REGION. HIGHER
RESOLUTION GUIDANCE IS IN GENERAL AGREEMENT WITH THE NAM/RGEM/HRRR
ALL SHOWING THIS GENERAL TREND. THERE IS STILL A POSSIBILITY THAT
THIS WILL HOLD TOGETHER LONG ENOUGH TO HAVE SOME IMPACT ON OUR
CWA...WITH THE SAINT LAWRENCE RIVER AND NORTH COUNTRY AND POSSIBLY
PORTIONS OF THE NIAGARA FRONTIER THE AREAS TO WATCH. IT WILL BE
TRICKY...SINCE THE LINE WILL PROBABLY BE QUITE IMPRESSIVE JUST
UPSTREAM OF THE LAKE BREEZE...WITH BOWING LINE SEGMENTS CAPABLE OF
PRODUCING STRONG WINDS. THIS INITIAL LINE WILL IMPACT OUR REGION
BETWEEN 700 PM AND 1000 PM.
BEHIND THIS...IS A SECONDARY LINE OF THUNDERSTORMS DEVELOPING
ALONG WHAT APPEARS TO BE A PRE-FRONTAL TROF WIND SHIFT BOUNDARY.
00/12Z RUNS OF THE NAM/RGEM AND RECENT RUNS OF THE HRRR CONTINUE
TO SUGGEST THAT THIS AREA WILL EXPAND...AND EVENTUALLY DROP ACROSS
OUR REGION DURING THE OVERNIGHT HOURS. THE LATER TIMING...AND
CLOSER PROXIMITY TO THE SHORTWAVE WILL MAKE THIS FEATURE MORE
LIKELY TO HOLD TOGETHER AS IT DROPS ACROSS THE LAKES AND ACROSS
WESTERN NEW YORK LATE TONIGHT AND INTO SATURDAY MORNING. THIS
TIMING IS CLIMATOLOGICALLY NOT FAVORABLE FOR SEVERE WEATHER...BUT
GIVEN THE SIGNIFICANT AMOUNT OF NIGHTTIME INSTABILITY...AND STILL
A FAIR AMOUNT OF SHEAR...IT WILL BEAR A RADAR WATCH IF IT DOES
INDEED DEVELOP AS FORECAST.
IN ADDITION TO THE SEVERE WEATHER THREAT...THERE WILL ALSO BE A
RISK FOR LOCALLY HEAVY DOWNPOURS. PRECIPITABLE WATER VALUES WILL
BE 1.75 TO 2.00 INCHES...AND WHILE STORMS WILL LIKELY BE
MOVING...LARGE AREAS OF CONVECTION OR BRIEF TRAINING COULD QUICKLY
ADD UP AND LEAD TO LOCALIZED FLOODING.
ON SATURDAY...EXPECT MOST OF THE SHOWERS AND THUNDERSTORM ACTIVITY
TO SLIDE TO THE SOUTH AND EAST OF THE AREA LATE MORNING AND INTO
THE AFTERNOON HOURS. THE ACTUAL FRONTAL BOUNDARY WILL NOT CROSS
UNTIL LATER IN THE DAY...BUT MUCH DRIER AIR WILL MOVE IN BEHIND
THE PRE-FRONTAL TROF WITH ONLY MARGINAL CHANCE FOR ANY SHOWERS OR
THUNDERSTORMS ALONG THE FRONT ITSELF WHICH WILL CROSS LATE IN THE
DAY SATURDAY. WITH COOLER AIR MOVING IN AND LINGERING
PRECIPITATION...TEMPERATURES WILL BE NOTABLY COOLER ON
SATURDAY...WITH HIGHS MAINLY IN THE LOWER 80S.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
BY SATURDAY EVENING...MOST OF THE 12Z GUIDANCE PACKAGES ARE IN GOOD
AGREEMENT THAT THE COLD FRONTAL ZONE AND THE BULK OF ITS ASSOCIATED
PRECIPITATION WILL HAVE SLIPPED TO OUR SOUTH...SAVE FOR THE NAM
WHICH IS A SLOWER OUTLIER. AS THIS PARTICULAR MODEL HAS SHOWN SOME
RUN-TO-RUN INCONSISTENCIES WITH THE TIMING OF THE FRONT OVER THE
PAST DAY OR SO...WILL DISREGARD IT IN FAVOR OF THE FASTER GFS/
GEM/ECMWF CONSENSUS AND OUR EXISTING CONTINUITY...ALL OF WHICH
ADVERTISE A GENERALLY DRY NIGHT. IN THE WAKE OF THE FRONT...A HIGHLY
ANTICIPATED COOLER AND DRIER AIRMASS WILL SPREAD SOUTH ACROSS OUR
AREA THROUGH THE COURSE OF THE NIGHT...FINALLY BRINGING SOME MUCH
WELCOMED RELIEF FROM THE TROPICAL HEAT AND HUMIDITY LEVELS OF THE
PAST WEEK. EXPECT OVERNIGHT LOWS TO DROP TO THE MID 50S TO LOWER
60S...WHILE SURFACE DEWPOINTS FALL BACK TO MUCH MORE COMFORTABLE
LEVELS IN THE 50S.
WITH THE WATERS OF THE LOWER GREAT LAKES NOW IN THE MID TO UPPER 70S
/OR AROUND +25C/...AND THE INCOMING COOLER AIRMASS EVENTUALLY
FEATURING 850 MB TEMPS OF AROUND +10C BY LATER IN THE NIGHT...WE MAY
WELL SEE SOME LAKE EFFECT CLOUDINESS DEVELOP SOUTH OF THE LAKES
OVERNIGHT...THOUGH THE INCOMING AIRMASS WILL LIKELY REMAIN TOO DRY
AND FEATURE TOO LOW OF A SUBSIDENCE INVERSION TO SUPPORT ANY LAKE
EFFECT SHOWERS.
SUNDAY AND SUNDAY NIGHT...SURFACE HIGH PRESSURE WILL SETTLE DIRECTLY
ACROSS THE LOWER LAKES AND NEW YORK STATE IN THE WAKE OF THE COLD
FRONT. COUPLED WITH STRONG MIDSUMMER DIURNAL EFFECTS...THIS SHOULD
RESULT IN ANY LAKE EFFECT CLOUDS FROM SATURDAY NIGHT BREAKING UP
DURING THE COURSE OF SUNDAY MORNING...LEADING TO A DECENT AMOUNT OF
SUNSHINE EVERYWHERE FOR THE AFTERNOON. MEANWHILE...850 MB TEMPS
RANGING FROM +9C NORTH TO +13C SOUTH SHOULD SUPPORT RATHER PLEASANT
HIGHS IN THE MID TO UPPER 70S...WHILE DEWPOINTS CONTINUE TO LOWER TO
THE 50-55 DEGREE RANGE WITH DIURNAL MIXING. THE COOLER AND QUIET
WEATHER WILL THEN CONTINUE INTO SUNDAY NIGHT...WHEN LOWS SHOULD
RANGE THROUGH THE 50S IN MOST LOCATIONS...WITH SOME UPPER 40S EVEN
POSSIBLE ACROSS PORTIONS OF THE NORTH COUNTRY. WITH THE LOW LEVEL
FLOW VEERING MORE EASTERLY...DO NOT EXPECT LAKE EFFECT CLOUDINESS TO
BE A PROBLEM FOR SUNDAY NIGHT...THOUGH THERE WILL PROBABLY BE SOME
INCREASE IN MID/HIGH CLOUDS OVERNIGHT IN ADVANCE OF A MODEST
SHORTWAVE TROUGH THAT WILL BE WORKING INTO THE CENTRAL GREAT LAKES.
MONDAY AND MONDAY NIGHT...THE SURFACE HIGH WILL SLIDE EAST ACROSS
NEW ENGLAND AND OUT TO SEA...WHILE THE AFOREMENTIONED SHORTWAVE
TROUGH TO OUR WEST SETTLES ACROSS THE LOWER LAKES AND NY/PA...WHILE
ALSO SPAWNING SOME SEMBLANCE OF A WEAK SURFACE REFLECTION. WHILE THE
VARIOUS GUIDANCE PACKAGES STILL DIFFER WITH RESPECT TO HOW FAST
THIS SYSTEM ARRIVES AND EXACTLY HOW WELL DEVELOPED IT WILL BE...ALL
HAVE CONTINUED THE RECENT TREND TOWARD A FASTER AND SOMEWHAT MORE
DEVELOPED SYSTEM...WITH A PLUME OF DEEPER MOISTURE AND WEAK TO
MODEST ISENTROPIC LIFT EVENTUALLY ADVECTING INTO OUR AREA BETWEEN
MONDAY AFTERNOON AND MONDAY NIGHT. WITH THIS AND OUR EXISTING
CONTINUITY OF A TOTALLY DRY FORECAST BOTH IN MIND...HAVE ELECTED TO
GRADUALLY INTRODUCE SOME LOWER CHANCE POPS INTO AREAS SOUTH OF LAKE
ONTARIO MONDAY AFTERNOON...BEFORE BRINGING HIGHER CHANCE RANGE POPS
INTO THE ENTIRE AREA MONDAY NIGHT. THE HIGHEST PRECIPITATION CHANCES
WILL BE FOCUSED ACROSS OUR FINGER LAKES AND NORTH COUNTRY ZONES...
WHICH WILL BE CLOSEST TO THE BEST AREA OF DEEPER MOISTURE AND
ISENTROPIC LIFT. TEMPS THROUGH THIS LATTER PORTION OF THE PERIOD
WILL RETURN TO MIDSUMMER NORMS GIVEN THE WEAK WARM AIR ADVECTION
PATTERN...WITH DAYTIME HIGHS OF AROUND 80 EXPECTED ON MONDAY...
FOLLOWED BY LOWS IN THE LOWER TO MID 60S MONDAY NIGHT.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
IN THE LONG TERM PORTION OF THE FORECAST...THE LARGE-SCALE WEATHER
PATTERN ACROSS NORTH AMERICA WILL REVERT TO ONE WE HAVE BEEN MORE
FAMILIAR WITH FOR THE BULK OF THE SPRING AND SUMMER...THAT OF A
BROAD RIDGE OVER THE ROCKIES AND WESTERN PLAINS...WITH A
CORRESPONDING BROAD DOWNSTREAM TROUGH DEVELOPING OVER THE GREAT
LAKES AND NORTHEAST. THIS CHANGE IN THE PATTERN WILL RESULT IN AN
EXTENDED PERIOD OF MORE NORMAL SUMMERTIME TEMPERATURES FOR OUR
REGION...WITH DAILY HIGHS AVERAGING WITHIN A FEW DEGREES OF 80 EACH
DAY...AND NIGHTTIME LOWS GENERALLY RANGING IN THE LOWER TO MID 60S.
WITH RESPECT TO PRECIPITATION CHANCES...THE FORECAST PICTURE REMAINS
CONSIDERABLY MORE MUDDLED. UNDER THE EXPECTED LARGE-SCALE FLOW
REGIME...NUMEROUS PIECES OF SHORTWAVE ENERGY SHOULD ROTATE THROUGH
THE DEVELOPING TROUGH AND LEAD TO PERIODIC CHANCES FOR SHOWERS AND
THUNDERSTORMS...HOWEVER THE MEDIUM RANGE GUIDANCE REMAINS ALL OVER
THE MAP WITH RESPECT TO THE TIMING AND STRENGTH OF THESE FEATURES.
WITH THIS IN MIND...HAVE JUST CONTINUED TO BROADBRUSH SOME LOW
CHANCE POPS ACROSS THE ENTIRE PERIOD FOR NOW...AND WILL WAIT UNTIL
BETTER MODEL AGREEMENT DEVELOPS BEFORE TRYING TO PROVIDE MORE
REFINED/DETAILED PRECIPITATION PROBABILITIES AND TIMING. ALL THIS
SAID...THIS PERIOD LOOKS TO BE FAR FROM A WASHOUT AT THIS TIME...
WITH ANY SHOTS OF SHOWERS/STORMS LIKELY TO ALTERNATE WITH FREQUENT
DRY PERIODS.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
FOR THE 18Z TAF CYCLE...GUSTY SW WINDS TO BE THE MAIN IMPACT FOR
THIS AFTERNOON...WITH BUF/IAG/ROC/ART ALL SEEING PREVAILING GUSTS
IN THE 30 TO 35 KT RANGE. WIDELY SCATTERED THUNDERSTORMS MAY
BRIEFLY IMPACT JHW.
AFTER THIS...A LINE OF THUNDERSTORMS WILL APPROACH FROM THE WEST
23Z. THIS AREA WILL PROBABLY WEAKEN AS IT MOVES INTO OUR
REGION...BUT MAY HOLD TOGETHER LONG ENOUGH TO IMPACT IAG/ART...AND
POSSIBLY BUF/ROC DURING THE EVENING HOURS. STEADIER THUNDERSTORMS
ARE LIKELY LATE TONIGHT AS A LARGER AREA IS FORECAST TO DROP
ACROSS THE REGION. ALL THUNDERSTORMS MAY CONTAIN GUSTY WINDS AND
WIND SHIFTS...WITH HEAVY RAIN LOWERING VSBY TO 1SM.
STORMS WILL DROP FROM N-S LATE TONIGHT AND INTO SATURDAY
MORNING...WITH CONDITIONS IMPROVING TO VFR.
OUTLOOK...
SATURDAY NIGHT THROUGH MONDAY MORNING...VFR.
MONDAY AFTERNOON THROUGH WEDNESDAY...MAINLY VFR WITH A CHANCE OF
SHOWERS/THUNDERSTORMS.
&&
.MARINE...
AN INCREASING PRESSURE GRADIENT WILL BRING GUSTY SOUTHWEST WINDS
TODAY TO THE LAKES...ESPECIALLY LAKE ERIE AND ACROSS BOTH RIVERS.
WINDS AND WAVES WILL BUILD TO SMALL CRAFT ADVISORY LEVELS THROUGH
THE DAY TODAY...THEN LINGER AT THESE LEVELS THROUGH TONIGHT/EARLY
SATURDAY. WILL CONTINUE WITH SMALL CRAFT ADVISORIES FOR ALL
NEARSHORE WATERS OF LAKES ERIE AND ONTARIO...AS WELL AS THE NIAGARA
RIVER AND SAINT LAWRENCE RIVER.
A GREATER AND MORE WIDESPREAD SHOWER AND THUNDERSTORM CHANCES WILL
ARRIVE FOR TONIGHT AS A COLD FRONT MAKES ITS WAY ACROSS THE LOWER
LAKES...BRINGING THE POTENTIAL FOR STRONGER TO POTENTIALLY SEVERE
STORMS WITH LOCALLY STRONG WINDS AND HIGHER WAVES.
CONDITIONS WILL RETURN TO BELOW SCA LATER ON SATURDAY AND REMAIN
BELOW SCA THROUGH THE REMAINDER OF THE WEEKEND AND INTO THE
BEGINNING OF NEXT WEEK.
&&
.CLIMATE...
HOT AND HUMID WEATHER WILL CONTINUE THROUGH TODAY AND TEMPERATURES
WILL APPROACH RECORD HIGHS THIS AFTERNOON...THOUGH THE ONLY SITE
THAT IS EXPECTED TO AT LEAST TIE IT/S RECORD HIGH IS ROCHESTER.
HOWEVER...WITH READINGS IN THE UPPER 70S THIS FRIDAY MORNING...RECORD
WARM LOWS SHOULD BE BROKEN AT ALL THREE LOCATIONS BELOW.
HERE ARE THE RECORDS FOR THE REMAINDER OF THE WORK WEEK.
BUFFALO..
DATE RECORD HIGH RECORD WARM LOW
FRI 7/19 92 75
ROCHESTER..
DATE RECORD HIGH RECORD WARM LOW
FRI 7/19 95 75
WATERTOWN..
DATE RECORD HIGH RECORD WARM LOW
FRI 7/19 92 72
HERE ARE THE MONTHLY AND ALL TIME RECORD LOW MINIMUMS...
BUFFALO..
JULY.. 78 1897
ALL TIME.. 79 2006
ROCHESTER..
JULY (ALL TIME)..81 1936 AND 1940
WATERTOWN..
JULY (ALL TIME).. 79 2011
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ001>006-011-
013-014.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ001-002-010-
011-019-085.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR LEZ020.
SMALL CRAFT ADVISORY UNTIL 10 AM EDT SATURDAY FOR LEZ040-
041.
SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR
LOZ030-042-043.
SMALL CRAFT ADVISORY UNTIL 10 AM EDT SATURDAY FOR LOZ044-
045.
SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR
SLZ022-024.
&&
$$
SYNOPSIS...THOMAS
NEAR TERM...APFFEL
SHORT TERM...JJR
LONG TERM...JJR
AVIATION...APFFEL
MARINE...APFFEL/THOMAS
CLIMATE...HITCHCOCK/WOOD/THOMAS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
256 PM EDT FRI JUL 19 2013
.SYNOPSIS...
HOT AND HUMID CONDITIONS WILL PERSIST FOR ONE MORE DAY...WITH PLENTY
OF SUNSHINE AND MAINLY RAIN FREE CONDITIONS TODAY. THERE WILL BE JUST
AN ISOLATED STORM WELL INLAND FROM THE LAKES THIS AFTERNOON. THERE
WILL ALSO BE A GUSTY SOUTHWESTERLY WIND TODAY AHEAD OF A COLD
FRONT...WITH THE COLD FRONT BRINGING SOME SHOWERS AND THUNDERSTORMS
FRIDAY NIGHT INTO SATURDAY ACROSS THE REGION. COMFORTABLE CONDITIONS
WILL FINALLY RETURN BEHIND THE FRONT FOR SUNDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
FOR THE REMAINDER OF THIS AFTERNOON HOT AND WINDY CONDITIONS WILL
PERSIST ACROSS THE REGION. AN UPPER LEVEL TROF SOUTH OF HUDSON BAY
WILL DIVE TOWARD THE UPPER LAKES THROUGH TONIGHT...PUSHING AN
ASSOCIATED COLD FRONTAL BOUNDARY TOWARD OUR REGION. WHILE THE
FRONT ITSELF WILL REMAIN WELL UPSTREAM...THIS WILL RESULT IN A
TIGHTENING PRESSURE GRADIENT. THE VAD WIND PROFILE ALREADY SHOWS
40 KNOT WINDS AT 925 MB...AND THESE ARE FORECAST TO INCREASE A BIT
MORE THROUGH SUNSET FROM WEST TO EAST. THESE SOUTHWEST WINDS
SHOULD FAIRLY READILY MIX TO THE SURFACE...WITH THE LAKE BREEZE
ENHANCING THIS FLOW TO THE NORTHEAST OF THE LAKES. THE WINDIEST
CONDITIONS SHOULD BE ACROSS THE NIAGARA FRONTIER AND IMMEDIATE LAKE
ERIE SHORELINE...WHICH INCLUDES THE BUFFALO METRO AREA. GUSTS
SHOULD GENERALLY RUN IN THE 40 TO 45 MPH RANGE IN THIS AREA...WITH
PEAK GUSTS LIKELY TO TOP OUT NEAR 50 MPH. EXPECT THAT WITH THE
FULL FOLIAGE...THIS WILL RESULT IN A FEW DOWNED TREE LIMBS...WITH
SOME SPOTTY POWER OUTAGES POSSIBLE. ELSEWHERE WILL BE BREEZY AS
WELL...BUT INTERIOR LOCATIONS WILL GENERALLY LESS WINDY.
THE OTHER BIG ISSUE WILL SIMPLY BE THE HOT WEATHER. THE SW FLOW
OFF THE LAKE SHOULD HOLD TEMPERATURES 90 IN THE BUFFALO
AREA...BUT ROCHESTER EASTWARD THIS FLOW WILL DOWNSLOPE AND ADD A
FEW MORE DEGREES TO THE ALREADY HOT WEATHER. FOR MANY THIS WILL BE
THE HOTTEST DAY SO FAR...WITH HIGHS IN THE MID 90S. THIS COMBINED
WITH DEW POINTS IN THE LOWER 70S WILL RESULT IN HEAT INDEX VALUES
OVER 100 FOR ROCHESTER AND IN THE NORTHERN GENESEE VALLEY AND
FINGER LAKES REGIONS. OTHERWISE...EXPECT SCATTERED SHOWERS AND
THUNDERSTORMS ACROSS WESTERN PORTIONS OF THE SOUTHERN TIER AND
EASTERN LAKE ONTARIO REGION TO DISSIPATE TOWARD THIS EVENING...AS
DAYTIME HEATING DIMINISHES AND AS WINDS INCREASE MIXING AND EXPAND
THE LAKE SHADOWING.
FOR TONIGHT AND INTO SATURDAY...THE FOCUS WILL SHIFT TO THE
POTENTIAL FOR SEVERE WEATHER...WITH LOCALLY HEAVY DOWNPOURS. THIS
WILL LIKELY COME IN TWO WAVES. THE FIRST CAN ALREADY BE SEEN
CLEARLY EARLY THIS AFTERNOON...ASSOCIATED WITH A LINE OF
THUNDERSTORMS DEVELOPING ACROSS CENTRAL MICHIGAN TO LAKE HURON.
THIS INITIAL WAVE WILL TRACK TOWARD OUR REGION THROUGH THE
AFTERNOON HOURS...BUT GIVEN THE STRONG SW FLOW ACROSS THE LAKES
EXPECT IT WILL WEAKEN RAPIDLY AS IT APPROACHES OUR REGION. HIGHER
RESOLUTION GUIDANCE IS IN GENERAL AGREEMENT WITH THE NAM/RGEM/HRRR
ALL SHOWING THIS GENERAL TREND. THERE IS STILL A POSSIBILITY THAT
THIS WILL HOLD TOGETHER LONG ENOUGH TO HAVE SOME IMPACT ON OUR
CWA...WITH THE SAINT LAWRENCE RIVER AND NORTH COUNTRY AND POSSIBLY
PORTIONS OF THE NIAGARA FRONTIER THE AREAS TO WATCH. IT WILL BE
TRICKY...SINCE THE LINE WILL PROBABLY BE QUITE IMPRESSIVE JUST
UPSTREAM OF THE LAKE BREEZE...WITH BOWING LINE SEGMENTS CAPABLE OF
PRODUCING STRONG WINDS. THIS INITIAL LINE WILL IMPACT OUR REGION
BETWEEN 700 PM AND 1000 PM.
BEHIND THIS...IS A SECONDARY LINE OF THUNDERSTORMS DEVELOPING
ALONG WHAT APPEARS TO BE A PRE-FRONTAL TROF WIND SHIFT BOUNDARY.
00/12Z RUNS OF THE NAM/RGEM AND RECENT RUNS OF THE HRRR CONTINUE
TO SUGGEST THAT THIS AREA WILL EXPAND...AND EVENTUALLY DROP ACROSS
OUR REGION DURING THE OVERNIGHT HOURS. THE LATER TIMING...AND
CLOSER PROXIMITY TO THE SHORTWAVE WILL MAKE THIS FEATURE MORE
LIKELY TO HOLD TOGETHER AS IT DROPS ACROSS THE LAKES AND ACROSS
WESTERN NEW YORK LATE TONIGHT AND INTO SATURDAY MORNING. THIS
TIMING IS CLIMATOLOGICALLY NOT FAVORABLE FOR SEVERE WEATHER...BUT
GIVEN THE SIGNIFICANT AMOUNT OF NIGHTTIME INSTABILITY...AND STILL
A FAIR AMOUNT OF SHEAR...IT WILL BEAR A RADAR WATCH IF IT DOES
INDEED DEVELOP AS FORECAST.
IN ADDITION TO THE SEVERE WEATHER THREAT...THERE WILL ALSO BE A
RISK FOR LOCALLY HEAVY DOWNPOURS. PRECIPITABLE WATER VALUES WILL
BE 1.75 TO 2.00 INCHES...AND WHILE STORMS WILL LIKELY BE
MOVING...LARGE AREAS OF CONVECTION OR BRIEF TRAINING COULD QUICKLY
ADD UP AND LEAD TO LOCALIZED FLOODING.
ON SATURDAY...EXPECT MOST OF THE SHOWERS AND THUNDERSTORM ACTIVITY
TO SLIDE TO THE SOUTH AND EAST OF THE AREA LATE MORNING AND INTO
THE AFTERNOON HOURS. THE ACTUAL FRONTAL BOUNDARY WILL NOT CROSS
UNTIL LATER IN THE DAY...BUT MUCH DRIER AIR WILL MOVE IN BEHIND
THE PRE-FRONTAL TROF WITH ONLY MARGINAL CHANCE FOR ANY SHOWERS OR
THUNDERSTORMS ALONG THE FRONT ITSELF WHICH WILL CROSS LATE IN THE
DAY SATURDAY. WITH COOLER AIR MOVING IN AND LINGERING
PRECIPITATION...TEMPERATURES WILL BE NOTABLY COOLER ON
SATURDAY...WITH HIGHS MAINLY IN THE LOWER 80S.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
THE MAIN STORY THIS WEEKEND WILL BE THE PASSAGE OF A COLD FRONT THAT
WILL BREAK THE HEAT WAVE THE REGION HAS BEEN EXPERIENCING OF LATE
AND USHER IN A RETURN TO MUCH MORE SEASONABLE TEMPERATURES. AS WE
OPEN THE WEEKEND SATURDAY MORNING HOWEVER...SHOWERS AND
THUNDERSTORMS ASSOCIATED WITH THE PRE-FRONTAL TROUGH WILL STILL
LIKELY BE CROSSING THE FORECAST AREA. THIS INITIAL BATCH OF
CONVECTIVE ACTIVITY SHOULD TAPER OFF FROM NORTHWEST TO SOUTHEAST
DURING THE MORNING HOURS WITH THE PASSAGE OF THE TROUGH...HOWEVER A
SECOND ROUND OF SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AGAIN
DURING THE AFTERNOON/EARLY EVENING HOURS ACCOMPANYING THE PASSAGE OF
THE ACTUAL COLD FRONT. WITH THE LOW LEVEL JET WELL TO OUR EAST AND
MODEL CAPES ONLY IN THE 500-1000 J/KG RANGE...ANY SHOWERS AND
THUNDERSTORMS THAT DO OCCUR SHOULD REMAIN RELATIVELY BENIGN. THE
COMBINATION OF CLOUD COVER AND THE GRADUAL FILTERING OF COOLER AIR
INTO THE REGION BEHIND THE PRE-FRONTAL TROUGH MEANS THAT MOST AREAS
SHOULD ONLY TOP OUT IN THE LOWER 80S...THOUGH AREAS SOUTHEAST OF
LAKE ONTARIO COULD STILL SEE HIGHS IN THE MID 80S THANKS TO
DOWNSLOPING SOUTHWESTERLY FLOW AHEAD OF THE COLD FRONT.
THE COLD FRONT WILL CROSS WESTERN/NORTH CENTRAL NEW YORK SATURDAY
EVENING BRINGING AN END TO ANY LINGERING PRECIPITATION AS MUCH
COOLER AND DRIER AIR ADVECTS INTO THE REGION. WITH THE MUCH
ANTICIPATED ARRIVAL OF THIS AIRMASS LOOK FOR TEMPERATURES TO DIP
INTO THE MID 50S ACROSS THE NORTH COUNTRY AND SOUTHERN TIER WHILE
THE LAKE PLAINS AND FINGER LAKES WILL COOL INTO THE LOWER 60S. THE
COOLING TEMPERATURES COMBINED WITH ANY LINGERING MOISTURE FROM
FRIDAY NIGHT/SATURDAY/S RAINFALL COULD LEAD TO PATCHY FOG ACROSS THE
SOUTHERN TIER.
DRY AND MILD WEATHER WILL PREVAIL ON SUNDAY AND SUNDAY NIGHT AS HIGH
PRESSURE SETTLES OVER THE GREAT LAKES IN THE WAKE OF THE COLD FRONT.
HIGHS IN THE MID TO UPPER 70S ON SUNDAY WILL PROVIDE A REFRESHING
BREAK FROM THE RECENT HEAT. WHILE MOST AREAS SHOULD SEE PLENTY OF
SUNSHINE...WITH 850MB TEMPERATURES COOLING TO THE +8 TO +10C RANGE
AND LAKE TEMPERATURES RUNNING A TOASTY +25C...CANNOT RULE OUT THE
POSSIBILITY OF SOME LAKE INDUCED CLOUD COVER CREEPING INTO WESTERN
NEW YORK. ANY LAKE INDUCED CLOUD COVER SHOULD DIMINISH SUNDAY
EVENING AS WINDS VEER TO TO THE EAST...HOWEVER EXPECT MID/HIGH
CLOUDS TO MOVE IN FROM THE WEST LATER SUNDAY NIGHT AHEAD OF A WEAK
SHORTWAVE CROSSING THE CENTRAL GREAT LAKES.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
BY MONDAY HIGH PRESSURE WILL DRIFT OFF THE NEW ENGLAND COAST...
ALLOWING SOUTHERLY RETURN FLOW TO BEGIN. MODELS CONTINUE TO BE A
LITTLE MORE AGGRESSIVE IN BRINGING A PLUME OF DEEPER MOISTURE AND
PERHAPS A FEW SHOWERS INTO EASTERN PA AND NY...BUT IT STILL APPEARS
THIS WILL REMAIN MAINLY TO OUR EAST. HAVE CONTINUED WITH A DRY
FORECAST FOR MONDAY WITH TEMPERATURES MODERATING TO VERY CLOSE TO
AVERAGE.
TUESDAY THROUGH THURSDAY A BROAD TROUGH WILL SLOWLY EVOLVE IN THE
GREAT LAKES. NUMEROUS SHORTWAVE FEATURES WILL ROTATE THROUGH THE
DEVELOPING TROUGH...BUT MODEL GUIDANCE REMAINS OUT OF PHASE WITH
RESPECT TO TIMING AND AMPLITUDE OF THESE FEATURES. AT THIS POINT
HAVE JUST BLANKETED THE PERIOD WITH LOW CHANCE POPS UNTIL BETTER
MODEL AGREEMENT ALLOWS FOR MORE REFINED TIMING. TEMPERATURES WILL
RETURN TO A LITTLE ABOVE AVERAGE AND HUMIDITY WILL INCREASE...BUT
BOTH WILL REMAIN BELOW THE LEVELS OF THIS WEEK.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
FOR THE 18Z TAF CYCLE...GUSTY SW WINDS TO BE THE MAIN IMPACT FOR
THIS AFTERNOON...WITH BUF/IAG/ROC/ART ALL SEEING PREVAILING GUSTS
IN THE 30 TO 35 KT RANGE. WIDELY SCATTERED THUNDERSTORMS MAY
BRIEFLY IMPACT JHW.
AFTER THIS...A LINE OF THUNDERSTORMS WILL APPROACH FROM THE WEST
23Z. THIS AREA WILL PROBABLY WEAKEN AS IT MOVES INTO OUR
REGION...BUT MAY HOLD TOGETHER LONG ENOUGH TO IMPACT IAG/ART...AND
POSSIBLY BUF/ROC DURING THE EVENING HOURS. STEADIER THUNDERSTORMS
ARE LIKELY LATE TONIGHT AS A LARGER AREA IS FORECAST TO DROP
ACROSS THE REGION. ALL THUNDERSTORMS MAY CONTAIN GUSTY WINDS AND
WIND SHIFTS...WITH HEAVY RAIN LOWERING VSBY TO 1SM.
STORMS WILL DROP FROM N-S LATE TONIGHT AND INTO SATURDAY
MORNING...WITH CONDITIONS IMPROVING TO VFR.
OUTLOOK...
SATURDAY NIGHT THROUGH MONDAY MORNING...VFR.
MONDAY AFTERNOON THROUGH WEDNESDAY...MAINLY VFR WITH A CHANCE OF
SHOWERS/THUNDERSTORMS.
&&
.MARINE...
AN INCREASING PRESSURE GRADIENT WILL BRING GUSTY SOUTHWEST WINDS
TODAY TO THE LAKES...ESPECIALLY LAKE ERIE AND ACROSS BOTH RIVERS.
WINDS AND WAVES WILL BUILD TO SMALL CRAFT ADVISORY LEVELS THROUGH
THE DAY TODAY...THEN LINGER AT THESE LEVELS THROUGH TONIGHT/EARLY
SATURDAY. WILL CONTINUE WITH SMALL CRAFT ADVISORIES FOR ALL
NEARSHORE WATERS OF LAKES ERIE AND ONTARIO...AS WELL AS THE NIAGARA
RIVER AND SAINT LAWRENCE RIVER.
A GREATER AND MORE WIDESPREAD SHOWER AND THUNDERSTORM CHANCES WILL
ARRIVE FOR TONIGHT AS A COLD FRONT MAKES ITS WAY ACROSS THE LOWER
LAKES...BRINGING THE POTENTIAL FOR STRONGER TO POTENTIALLY SEVERE
STORMS WITH LOCALLY STRONG WINDS AND HIGHER WAVES.
CONDITIONS WILL RETURN TO BELOW SCA LATER ON SATURDAY AND REMAIN
BELOW SCA THROUGH THE REMAINDER OF THE WEEKEND AND INTO THE
BEGINNING OF NEXT WEEK.
&&
.CLIMATE...
HOT AND HUMID WEATHER WILL CONTINUE THROUGH TODAY AND TEMPERATURES
WILL APPROACH RECORD HIGHS THIS AFTERNOON...THOUGH THE ONLY SITE
THAT IS EXPECTED TO AT LEAST TIE IT/S RECORD HIGH IS ROCHESTER.
HOWEVER...WITH READINGS IN THE UPPER 70S THIS FRIDAY MORNING...RECORD
WARM LOWS SHOULD BE BROKEN AT ALL THREE LOCATIONS BELOW.
HERE ARE THE RECORDS FOR THE REMAINDER OF THE WORK WEEK.
BUFFALO..
DATE RECORD HIGH RECORD WARM LOW
FRI 7/19 92 75
ROCHESTER..
DATE RECORD HIGH RECORD WARM LOW
FRI 7/19 95 75
WATERTOWN..
DATE RECORD HIGH RECORD WARM LOW
FRI 7/19 92 72
HERE ARE THE MONTHLY AND ALL TIME RECORD LOW MINIMUMS...
BUFFALO..
JULY.. 78 1897
ALL TIME.. 79 2006
ROCHESTER..
JULY (ALL TIME)..81 1936 AND 1940
WATERTOWN..
JULY (ALL TIME).. 79 2011
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ001>006-011-
013-014.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ001-002-010-
011-019-085.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR LEZ020.
SMALL CRAFT ADVISORY UNTIL 10 AM EDT SATURDAY FOR LEZ040-
041.
SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR
LOZ030-042-043.
SMALL CRAFT ADVISORY UNTIL 10 AM EDT SATURDAY FOR LOZ044-
045.
SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR
SLZ022-024.
&&
$$
SYNOPSIS...THOMAS
NEAR TERM...APFFEL
SHORT TERM...WOOD
LONG TERM...HITCHCOCK
AVIATION...APFFEL
MARINE...APFFEL/THOMAS
CLIMATE...HITCHCOCK/WOOD/THOMAS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1114 AM EDT FRI JUL 19 2013
.SYNOPSIS...
HOT AND HUMID CONDITIONS WILL PERSIST FOR ONE MORE DAY...WITH PLENTY
OF SUNSHINE AND MAINLY RAIN FREE CONDITIONS TODAY. THERE WILL BE JUST
AN ISOLATED STORM WELL INLAND FROM THE LAKES THIS AFTERNOON. THERE
WILL ALSO BE A GUSTY SOUTHWESTERLY WIND TODAY AHEAD OF A COLD
FRONT...WITH THE COLD FRONT BRINGING SOME SHOWERS AND THUNDERSTORMS
FRIDAY NIGHT INTO SATURDAY ACROSS THE REGION. COMFORTABLE CONDITIONS
WILL FINALLY RETURN BEHIND THE FRONT FOR SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
ANOTHER VERY WARM AND MUGGY START TO THE DAY TODAY WITH A FADING
AREA OF HIGH PRESSURE STILL ANCHORED NEAR THE SOUTHEAST COASTLINE.
AN AREA OF LOW PRESSURE NEAR JAMES BAY THIS MORNING IS PUSHING
EASTWARD...WITH SUPPORT FROM AN UPPER LEVEL SHORTWAVE SEEN ON WATER
VAPOR IMAGERY JUST TO THE SOUTHWEST OF HUDSON BAY. A COLD FRONT FROM
THIS AREA OF LOW PRESSURE IS SLICING ACROSS THE NORTHERN PLAINS AND
UPPER GREAT LAKES THIS EARLY MORNING.
AS OF 1000 AM...RADAR SHOWS A LONE SHOWER HAS DEVELOPED ACROSS
THE NORTHEAST SHORELINE OF LAKE ERIE. WHILE THIS STORM SHOULD
STRUGGLE TO MAKE IT ACROSS THE DEVELOPING LAKE SHADOW...EXPANDING
CUMULUS CLOUDS WITH SOME HINT OF QPF FROM THE HRRR AND 00Z RGEM
SUGGEST THERE MAY BE A FEW SHOWERS OR THUNDERSTORMS DEVELOPING
ACROSS WESTERN PORTIONS OF THE SOUTHERN TIER LATE MORNING/EARLY
AFTERNOON. AS WINDS ALOFT INCREASE...THIS ACTIVITY SHOULD GET
PUSHED FURTHER EAST OF THE LAKES...AS SHADOWING BECOMES MORE PRONOUNCED.
OTHERWISE...THE TWO PRIMARY CONCERNS FOR TODAY WILL BE THE HEAT
AND GUSTY WINDS...FOLLOWED BY THE PROSPECTS FOR STRONG
THUNDERSTORMS THIS EVENING AND OVERNIGHT.
TODAY A TIGHTENING PRESSURE GRADIENT BETWEEN THE AREA OF LOW
PRESSURE OVER ONTARIO CANADA AND THE SURFACE HIGH PRESSURE OVER THE
SOUTHEAST WILL BRING GUSTY SOUTHWEST WINDS ACROSS THE CWA. A LOW
LEVEL JET OF 40 TO 45 KNOTS ABOUT 2 TO 3K FEET ABOVE THE SURFACE
WILL PASS OVER THE REGION. WITH PLENTY OF SUNSHINE TODAY INCREASING
MIXING HEIGHTS...UPWARD INTO THIS LLJ GUSTY WINDS WILL BE BROUGHT
DOWN TO THE SURFACE. THE STRONGEST GUSTS WILL BE FOUND ALONG THE
LAKE ERIE SHORELINE AND INLAND ACROSS THE NIAGARA FRONTIER WHERE
FUNNELING UP LAKE ERIE WILL BRING GUSTS IN THE 40 TO 45 MPH RANGE.
WHILE THERE WILL JUST BE ISOLATED GUSTS ABOVE 45 MPH...HAVE DECIDED
TO ISSUE A WIND ADVISORY MORE SO FOR IMPACT OF THESE SUMMERTIME
WINDS SPEEDS...WITH TREES FULLY FOLIATED.
THE OTHER ISSUE FOR TODAY WILL BE THE HEAT. TEMPERATURES ALOFT WILL
RISE ABOUT A DEGREE FROM YESTERDAY WITH 19 TO 20C AIR ABOVE THE
EASTERN GREAT LAKES...AND A SOUTHWESTERLY DOWNSLOPE FLOW WILL BRING
PERHAPS THE HOTTEST DAY OF THE YEAR FOR LOWER ELEVATIONS.
TEMPERATURES WILL RISE TOWARDS 90 DEGREES THROUGH THE REGION...WITH
MID 90S LIKELY ACROSS THE NORTHERN NIAGARA FRONTIER AND TOWARDS THE
GENESEE VALLEY/FINGER LAKES REGION AND THE BLACK RIVER VALLEY. A
DOWNSLOPE FLOW ACROSS THE LOWER ELEVATIONS MAY BRING SPOTS TO NEAR
RECORD HEAT FOR THE DAY. WITH A MOIST AIRMASS REMAINING...DEWPOINTS
INTO THE LOWER 70S APPARENT TEMPERATURES WILL RISE ABOVE 100F FOR
MUCH OF OUR CWA. HAVE ALSO ISSUED A HEAT ADVISORY FOR NIAGARA
COUNTY...EASTWARD ACROSS ORLEANS/GENESEE AND INTO THE GENESEE VALLEY
AND FINGER LAKES REGION. OUTSIDE THIS AREA IT WILL STILL BE HOT WITH
APPARENT TEMPERATURES INTO THE 90S.
STRONG SOUTHWEST FLOW WILL BRING THE LAKE ERIE BREEZE WELL INLAND
TODAY AND SHADOW AREAS DOWNWIND OF BOTH GREAT LAKES. THE LACK OF
UPPER LEVEL SUPPORT FOR THUNDERSTORMS WILL AGAIN BRING THE PRIMARY
FOCUS FOR LIFT UPON THESE LAKE BREEZE BOUNDARIES...WITH SOME
ADDITIONAL LIFT FROM THE APPROACHING LLJ AND THE CONVERGENCE ALONG
THIS JET. A FEW THUNDERSTORMS ARE POSSIBLE ACROSS WELL INLAND
AREAS...AND ACROSS THE EASTERN LAKE ONTARIO REGION THIS AFTERNOON.
TONIGHT THE CONCERN WILL SHIFT FROM THE HEAT AND WINDS TO THE
THUNDERSTORMS THAT WILL BE FORMING ALONG A PRE FRONTAL TROUGH WELL
AHEAD OF THE MAIN COLD FRONT. THE TIMING OF THIS SURFACE TROUGH AND
SHOWER AND THUNDERSTORM ACTIVITY BRINGS IT INTO OUR REGION AFTER THE
PEAK DAYTIME HEATING. STILL SBCAPES OF 1000 TO 2000 J/KG WILL REMAIN
IN THIS VERY WARM AIRMASS...AND INCREASING MID LEVEL MOISTURE WILL
FUEL SHOWERS AND THUNDERSTORMS DROPPING SOUTHEASTWARD ACROSS THE
CWA.
ALOFT DYNAMICS BECOME A LITTLE MORE FAVORABLE FOR WIDESPREAD SHOWERS
AND THUNDERSTORMS TONIGHT WITH A 120 KNOT 250 HPA JET CENTERED OVER
QUEBEC WITH OUR EASTERN GREAT LAKES REGION WITHIN THE RIGHT ENTRANCE
REGION. THERE WILL ALSO BE FALLING HEIGHTS ALOFT AHEAD OF THE
SHORTWAVE THAT WILL SLIDE SOUTHWARD DOWN THE WEST SIDE OF HUDSON BAY
TODAY AND TOWARDS THE UPPER GREAT LAKES TONIGHT.
A STILL STRONG LLJ OF 35 TO 40 KNOTS WILL REMAIN ACROSS THE
CWA...AND THIS JET COMBINED WITH DOWNDRAFTS FROM THUNDERSTORMS WILL
POSE THE PROSPECTS FOR GUSTY TO DAMAGING WINDS WITH THE OVERNIGHT
CONVECTION. WILL CONTINUE TO MENTION GUSTY WINDS IN THE GRIDS ALONG
WITH THE HEAVY RAINFALL AS PWATS CLIMB TOWARDS 1.75 TO 2.00 INCHES.
WHILE THUNDERSTORMS ARE LIKELY ACROSS MUCH OF THE CWA TONIGHT...WILL
PLACE JUST A HIGH CHANCE ACROSS THE FAR SOUTHERN GENESEE VALLEY
WHICH WILL REMAIN SOUTH OF THE BEST UPPER LEVEL DYNAMICS...AND
EASTWARD OF THE SURFACE TROUGH.
THE COLD FRONT WILL ONLY REACH FROM ABOUT QUEBEC...TO DETROIT TO
CENTRAL ILLINOIS BY 12Z SATURDAY. THIS WILL LEAVE OUR REGION STILL
WITHIN THE WARM SECTOR WITH OVERNIGHT LOWS REMAINING IN THE 70S.
WITH WARM TEMPERATURES THROUGH 1 AM EDT...SOME OF OUR CLIMATE
SITES MAY SET NOT ONLY DAILY...BUT NEAR MONTHLY RECORD HIGH
MINIMUMS.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
THE MAIN STORY THIS WEEKEND WILL BE THE PASSAGE OF A COLD FRONT THAT
WILL BREAK THE HEAT WAVE THE REGION HAS BEEN EXPERIENCING OF LATE
AND USHER IN A RETURN TO MUCH MORE SEASONABLE TEMPERATURES. AS WE
OPEN THE WEEKEND SATURDAY MORNING HOWEVER...SHOWERS AND
THUNDERSTORMS ASSOCIATED WITH THE PRE-FRONTAL TROUGH WILL STILL
LIKELY BE CROSSING THE FORECAST AREA. THIS INITIAL BATCH OF
CONVECTIVE ACTIVITY SHOULD TAPER OFF FROM NORTHWEST TO SOUTHEAST
DURING THE MORNING HOURS WITH THE PASSAGE OF THE TROUGH...HOWEVER A
SECOND ROUND OF SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AGAIN
DURING THE AFTERNOON/EARLY EVENING HOURS ACCOMPANYING THE PASSAGE OF
THE ACTUAL COLD FRONT. WITH THE LOW LEVEL JET WELL TO OUR EAST AND
MODEL CAPES ONLY IN THE 500-1000 J/KG RANGE...ANY SHOWERS AND
THUNDERSTORMS THAT DO OCCUR SHOULD REMAIN RELATIVELY BENIGN. THE
COMBINATION OF CLOUD COVER AND THE GRADUAL FILTERING OF COOLER AIR
INTO THE REGION BEHIND THE PRE-FRONTAL TROUGH MEANS THAT MOST AREAS
SHOULD ONLY TOP OUT IN THE LOWER 80S...THOUGH AREAS SOUTHEAST OF
LAKE ONTARIO COULD STILL SEE HIGHS IN THE MID 80S THANKS TO
DOWNSLOPING SOUTHWESTERLY FLOW AHEAD OF THE COLD FRONT.
THE COLD FRONT WILL CROSS WESTERN/NORTH CENTRAL NEW YORK SATURDAY
EVENING BRINGING AN END TO ANY LINGERING PRECIPITATION AS MUCH
COOLER AND DRIER AIR ADVECTS INTO THE REGION. WITH THE MUCH
ANTICIPATED ARRIVAL OF THIS AIRMASS LOOK FOR TEMPERATURES TO DIP
INTO THE MID 50S ACROSS THE NORTH COUNTRY AND SOUTHERN TIER WHILE
THE LAKE PLAINS AND FINGER LAKES WILL COOL INTO THE LOWER 60S. THE
COOLING TEMPERATURES COMBINED WITH ANY LINGERING MOISTURE FROM
FRIDAY NIGHT/SATURDAY/S RAINFALL COULD LEAD TO PATCHY FOG ACROSS THE
SOUTHERN TIER.
DRY AND MILD WEATHER WILL PREVAIL ON SUNDAY AND SUNDAY NIGHT AS HIGH
PRESSURE SETTLES OVER THE GREAT LAKES IN THE WAKE OF THE COLD FRONT.
HIGHS IN THE MID TO UPPER 70S ON SUNDAY WILL PROVIDE A REFRESHING
BREAK FROM THE RECENT HEAT. WHILE MOST AREAS SHOULD SEE PLENTY OF
SUNSHINE...WITH 850MB TEMPERATURES COOLING TO THE +8 TO +10C RANGE
AND LAKE TEMPERATURES RUNNING A TOASTY +25C...CANNOT RULE OUT THE
POSSIBILITY OF SOME LAKE INDUCED CLOUD COVER CREEPING INTO WESTERN
NEW YORK. ANY LAKE INDUCED CLOUD COVER SHOULD DIMINISH SUNDAY
EVENING AS WINDS VEER TO TO THE EAST...HOWEVER EXPECT MID/HIGH
CLOUDS TO MOVE IN FROM THE WEST LATER SUNDAY NIGHT AHEAD OF A WEAK
SHORTWAVE CROSSING THE CENTRAL GREAT LAKES.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
BY MONDAY HIGH PRESSURE WILL DRIFT OFF THE NEW ENGLAND COAST...
ALLOWING SOUTHERLY RETURN FLOW TO BEGIN. MODELS CONTINUE TO BE A
LITTLE MORE AGGRESSIVE IN BRINGING A PLUME OF DEEPER MOISTURE AND
PERHAPS A FEW SHOWERS INTO EASTERN PA AND NY...BUT IT STILL APPEARS
THIS WILL REMAIN MAINLY TO OUR EAST. HAVE CONTINUED WITH A DRY
FORECAST FOR MONDAY WITH TEMPERATURES MODERATING TO VERY CLOSE TO
AVERAGE.
TUESDAY THROUGH THURSDAY A BROAD TROUGH WILL SLOWLY EVOLVE IN THE
GREAT LAKES. NUMEROUS SHORTWAVE FEATURES WILL ROTATE THROUGH THE
DEVELOPING TROUGH...BUT MODEL GUIDANCE REMAINS OUT OF PHASE WITH
RESPECT TO TIMING AND AMPLITUDE OF THESE FEATURES. AT THIS POINT
HAVE JUST BLANKETED THE PERIOD WITH LOW CHANCE POPS UNTIL BETTER
MODEL AGREEMENT ALLOWS FOR MORE REFINED TIMING. TEMPERATURES WILL
RETURN TO A LITTLE ABOVE AVERAGE AND HUMIDITY WILL INCREASE...BUT
BOTH WILL REMAIN BELOW THE LEVELS OF THIS WEEK.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
VFR FLIGHT CONDITIONS WERE IN PLACE AT 15Z ACROSS THE
REGION...WITH SOME BKN CIGS AROUND 3K FEET ACROSS THE SOUTHERN
TIER NEAR JHW.
THE PRESSURE GRADIENT WILL INCREASE TODAY IN ADVANCE OF AN
APPROACHING COLD FRONT SAGGING SOUTHWARD ACROSS ONTARIO PROVINCE...
WHICH WILL RESULT IN RATHER BREEZY TO WINDY CONDITIONS DEVELOPING
ACROSS THE AREA DURING THE MORNING...THEN CONTINUING THROUGH THE
AFTERNOON. EXPECT SOUTHWESTERLY SURFACE WINDS TO INCREASE TO 15-25
KTS WITH GUSTS TO AS HIGH AS 35-40 KTS BY EARLY AFTERNOON...WITH
THE STRONGEST WINDS MOST LIKELY DOWNWIND OF LAKE ERIE FROM
KBUF/KIAG OVER TO KROC.
WITH THE DEVELOPING STRONGER SOUTHWESTERLY FLOW...LAKE SHADOWS WILL
QUICKLY DEVELOP AND SPREAD ACROSS MUCH OF THE AREA THIS AFTERNOON...
THEREBY LIMITING ANY POTENTIAL FOR CONVECTION TO FAR SOUTHERN
PORTIONS OF THE SOUTHERN TIER/FINGER LAKES AND INTERIOR PORTIONS OF
THE NORTH COUNTRY FOR THE VAST MAJORITY OF THE DAY. THROUGH THE
EVENING HOURS CONVECTION WILL BEGIN TO EDGE INTO WNY AS WELL AS THE
NORTH COUNTRY. EXPECT CONDITIONS TO DROP TO MVFR OVERNIGHT AS
THE RAIN SHOWERS PRESS SOUTHEASTWARD ACROSS THE EASTERN GREAT LAKES
REGION. WITH INSTABILITY REMAINING THERE WILL ALSO LIKELY BE
THUNDERSTORMS ACCOMPANYING THE PRECIPITATION. RAIN SHOWERS WITH
THUNDERSTORMS WILL THEN CONTINUE TO FALL THROUGH THE END OF THE TAF
CYCLE. ANY OF THESE STORMS COULD BEING BRIEF PERIODS OF IFR FLIGHT
CONDITIONS.
OUTLOOK...
SATURDAY...A PERIOD OF SHOWERS AND THUNDERSTORMS IS LIKELY WITH
ASSOCIATED IFR/MVFR...WITH MAINLY VFR CONDITIONS OTHERWISE.
SUNDAY AND MONDAY...VFR.
TUESDAY...MAINLY VFR WITH A CHANCE OF SHOWERS/THUNDERSTORMS.
&&
.MARINE...
AN INCREASING PRESSURE GRADIENT WILL BRING GUSTY SOUTHWEST WINDS
TODAY TO THE LAKES...ESPECIALLY LAKE ERIE AND ACROSS BOTH RIVERS.
WINDS AND WAVES WILL BUILD TO SMALL CRAFT ADVISORY LEVELS THROUGH
THE DAY TODAY...THEN LINGER AT THESE LEVELS THROUGH TONIGHT/EARLY
SATURDAY. WILL CONTINUE WITH SMALL CRAFT ADVISORIES FOR ALL
NEARSHORE WATERS OF LAKES ERIE AND ONTARIO...AS WELL AS THE NIAGARA
RIVER AND SAINT LAWRENCE RIVER.
A GREATER AND MORE WIDESPREAD SHOWER AND THUNDERSTORM CHANCES WILL
ARRIVE FOR TONIGHT AS A COLD FRONT MAKES ITS WAY ACROSS THE LOWER
LAKES...BRINGING THE POTENTIAL FOR STRONGER TO POTENTIALLY SEVERE
STORMS WITH LOCALLY STRONG WINDS AND HIGHER WAVES.
CONDITIONS WILL RETURN TO BELOW SCA LATER ON SATURDAY AND REMAIN
BELOW SCA THROUGH THE REMAINDER OF THE WEEKEND AND INTO THE
BEGINNING OF NEXT WEEK.
&&
.CLIMATE...
HOT AND HUMID WEATHER WILL CONTINUE THROUGH TODAY AND TEMPERATURES
WILL APPROACH RECORD HIGHS THIS AFTERNOON...THOUGH THE ONLY SITE
THAT IS EXPECTED TO AT LEAST TIE IT/S RECORD HIGH IS ROCHESTER.
HOWEVER...WITH READINGS IN THE UPPER 70S THIS FRIDAY MORNING...RECORD
WARM LOWS SHOULD BE BROKEN AT ALL THREE LOCATIONS BELOW.
HERE ARE THE RECORDS FOR THE REMAINDER OF THE WORK WEEK.
BUFFALO..
DATE RECORD HIGH RECORD WARM LOW
FRI 7/19 92 75
ROCHESTER..
DATE RECORD HIGH RECORD WARM LOW
FRI 7/19 95 75
WATERTOWN..
DATE RECORD HIGH RECORD WARM LOW
FRI 7/19 92 72
HERE ARE THE MONTHLY AND ALL TIME RECORD LOW MINIMUMS...
BUFFALO..
JULY.. 78 1897
ALL TIME.. 79 2006
ROCHESTER..
JULY (ALL TIME)..81 1936 AND 1940
WATERTOWN..
JULY (ALL TIME).. 79 2011
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ001>006-011-
013-014.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ001-002-010-
011-019-085.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR LEZ020.
SMALL CRAFT ADVISORY UNTIL 10 AM EDT SATURDAY FOR LEZ040-
041.
SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR
LOZ030.
SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR LOZ042-
043.
SMALL CRAFT ADVISORY UNTIL 10 AM EDT SATURDAY FOR LOZ044-
045.
SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR
SLZ022-024.
&&
$$
SYNOPSIS...THOMAS
NEAR TERM...APFFEL/THOMAS
SHORT TERM...WOOD
LONG TERM...HITCHCOCK
AVIATION...APFFEL/THOMAS
MARINE...APFFEL/THOMAS
CLIMATE...HITCHCOCK/WOOD/THOMAS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1031 AM EDT FRI JUL 19 2013
.SYNOPSIS...
HOT AND HUMID CONDITIONS WILL PERSIST FOR ONE MORE DAY...WITH PLENTY
OF SUNSHINE AND MAINLY RAIN FREE CONDITIONS TODAY. THERE WILL BE JUST
AN ISOLATED STORM WELL INLAND FROM THE LAKES THIS AFTERNOON. THERE
WILL ALSO BE A GUSTY SOUTHWESTERLY WIND TODAY AHEAD OF A COLD
FRONT...WITH THE COLD FRONT BRINGING SOME SHOWERS AND THUNDERSTORMS
FRIDAY NIGHT INTO SATURDAY ACROSS THE REGION. COMFORTABLE CONDITIONS
WILL FINALLY RETURN BEHIND THE FRONT FOR SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
ANOTHER VERY WARM AND MUGGY START TO THE DAY TODAY WITH A FADING
AREA OF HIGH PRESSURE STILL ANCHORED NEAR THE SOUTHEAST COASTLINE.
AN AREA OF LOW PRESSURE NEAR JAMES BAY THIS MORNING IS PUSHING
EASTWARD...WITH SUPPORT FROM AN UPPER LEVEL SHORTWAVE SEEN ON WATER
VAPOR IMAGERY JUST TO THE SOUTHWEST OF HUDSON BAY. A COLD FRONT FROM
THIS AREA OF LOW PRESSURE IS SLICING ACROSS THE NORTHERN PLAINS AND
UPPER GREAT LAKES THIS EARLY MORNING.
AS OF 1000 AM...RADAR SHOWS A LONE SHOWER HAS DEVELOPED ACROSS
THE NORTHEAST SHORELINE OF LAKE ERIE. WHILE THIS STORM SHOULD
STRUGGLE TO MAKE IT ACROSS THE DEVELOPING LAKE SHADOW...EXPANDING
CUMULUS CLOUDS WITH SOME HINT OF QPF FROM THE HRRR AND 00Z RGEM
SUGGEST THERE MAY BE A FEW SHOWERS OR THUNDERSTORMS DEVELOPING
ACROSS WESTERN PORTIONS OF THE SOUTHERN TIER LATE MORNING/EARLY
AFTERNOON. AS WINDS ALOFT INCREASE...THIS ACTIVITY SHOULD GET
PUSHED FURTHER EAST OF THE LAKES...AS SHADOWING BECOMES MORE PRONOUNCED.
OTHERWISE...THE TWO PRIMARY CONCERNS FOR TODAY WILL BE THE HEAT
AND GUSTY WINDS...FOLLOWED BY THE PROSPECTS FOR STRONG
THUNDERSTORMS THIS EVENING AND OVERNIGHT.
TODAY A TIGHTENING PRESSURE GRADIENT BETWEEN THE AREA OF LOW
PRESSURE OVER ONTARIO CANADA AND THE SURFACE HIGH PRESSURE OVER THE
SOUTHEAST WILL BRING GUSTY SOUTHWEST WINDS ACROSS THE CWA. A LOW
LEVEL JET OF 40 TO 45 KNOTS ABOUT 2 TO 3K FEET ABOVE THE SURFACE
WILL PASS OVER THE REGION. WITH PLENTY OF SUNSHINE TODAY INCREASING
MIXING HEIGHTS...UPWARD INTO THIS LLJ GUSTY WINDS WILL BE BROUGHT
DOWN TO THE SURFACE. THE STRONGEST GUSTS WILL BE FOUND ALONG THE
LAKE ERIE SHORELINE AND INLAND ACROSS THE NIAGARA FRONTIER WHERE
FUNNELING UP LAKE ERIE WILL BRING GUSTS IN THE 40 TO 45 MPH RANGE.
WHILE THERE WILL JUST BE ISOLATED GUSTS ABOVE 45 MPH...HAVE DECIDED
TO ISSUE A WIND ADVISORY MORE SO FOR IMPACT OF THESE SUMMERTIME
WINDS SPEEDS...WITH TREES FULLY FOLIATED.
THE OTHER ISSUE FOR TODAY WILL BE THE HEAT. TEMPERATURES ALOFT WILL
RISE ABOUT A DEGREE FROM YESTERDAY WITH 19 TO 20C AIR ABOVE THE
EASTERN GREAT LAKES...AND A SOUTHWESTERLY DOWNSLOPE FLOW WILL BRING
PERHAPS THE HOTTEST DAY OF THE YEAR FOR LOWER ELEVATIONS.
TEMPERATURES WILL RISE TOWARDS 90 DEGREES THROUGH THE REGION...WITH
MID 90S LIKELY ACROSS THE NORTHERN NIAGARA FRONTIER AND TOWARDS THE
GENESEE VALLEY/FINGER LAKES REGION AND THE BLACK RIVER VALLEY. A
DOWNSLOPE FLOW ACROSS THE LOWER ELEVATIONS MAY BRING SPOTS TO NEAR
RECORD HEAT FOR THE DAY. WITH A MOIST AIRMASS REMAINING...DEWPOINTS
INTO THE LOWER 70S APPARENT TEMPERATURES WILL RISE ABOVE 100F FOR
MUCH OF OUR CWA. HAVE ALSO ISSUED A HEAT ADVISORY FOR NIAGARA
COUNTY...EASTWARD ACROSS ORLEANS/GENESEE AND INTO THE GENESEE VALLEY
AND FINGER LAKES REGION. OUTSIDE THIS AREA IT WILL STILL BE HOT WITH
APPARENT TEMPERATURES INTO THE 90S.
STRONG SOUTHWEST FLOW WILL BRING THE LAKE ERIE BREEZE WELL INLAND
TODAY AND SHADOW AREAS DOWNWIND OF BOTH GREAT LAKES. THE LACK OF
UPPER LEVEL SUPPORT FOR THUNDERSTORMS WILL AGAIN BRING THE PRIMARY
FOCUS FOR LIFT UPON THESE LAKE BREEZE BOUNDARIES...WITH SOME
ADDITIONAL LIFT FROM THE APPROACHING LLJ AND THE CONVERGENCE ALONG
THIS JET. A FEW THUNDERSTORMS ARE POSSIBLE ACROSS WELL INLAND
AREAS...AND ACROSS THE EASTERN LAKE ONTARIO REGION THIS AFTERNOON.
TONIGHT THE CONCERN WILL SHIFT FROM THE HEAT AND WINDS TO THE
THUNDERSTORMS THAT WILL BE FORMING ALONG A PRE FRONTAL TROUGH WELL
AHEAD OF THE MAIN COLD FRONT. THE TIMING OF THIS SURFACE TROUGH AND
SHOWER AND THUNDERSTORM ACTIVITY BRINGS IT INTO OUR REGION AFTER THE
PEAK DAYTIME HEATING. STILL SBCAPES OF 1000 TO 2000 J/KG WILL REMAIN
IN THIS VERY WARM AIRMASS...AND INCREASING MID LEVEL MOISTURE WILL
FUEL SHOWERS AND THUNDERSTORMS DROPPING SOUTHEASTWARD ACROSS THE
CWA.
ALOFT DYNAMICS BECOME A LITTLE MORE FAVORABLE FOR WIDESPREAD SHOWERS
AND THUNDERSTORMS TONIGHT WITH A 120 KNOT 250 HPA JET CENTERED OVER
QUEBEC WITH OUR EASTERN GREAT LAKES REGION WITHIN THE RIGHT ENTRANCE
REGION. THERE WILL ALSO BE FALLING HEIGHTS ALOFT AHEAD OF THE
SHORTWAVE THAT WILL SLIDE SOUTHWARD DOWN THE WEST SIDE OF HUDSON BAY
TODAY AND TOWARDS THE UPPER GREAT LAKES TONIGHT.
A STILL STRONG LLJ OF 35 TO 40 KNOTS WILL REMAIN ACROSS THE
CWA...AND THIS JET COMBINED WITH DOWNDRAFTS FROM THUNDERSTORMS WILL
POSE THE PROSPECTS FOR GUSTY TO DAMAGING WINDS WITH THE OVERNIGHT
CONVECTION. WILL CONTINUE TO MENTION GUSTY WINDS IN THE GRIDS ALONG
WITH THE HEAVY RAINFALL AS PWATS CLIMB TOWARDS 1.75 TO 2.00 INCHES.
WHILE THUNDERSTORMS ARE LIKELY ACROSS MUCH OF THE CWA TONIGHT...WILL
PLACE JUST A HIGH CHANCE ACROSS THE FAR SOUTHERN GENESEE VALLEY
WHICH WILL REMAIN SOUTH OF THE BEST UPPER LEVEL DYNAMICS...AND
EASTWARD OF THE SURFACE TROUGH.
THE COLD FRONT WILL ONLY REACH FROM ABOUT QUEBEC...TO DETROIT TO
CENTRAL ILLINOIS BY 12Z SATURDAY. THIS WILL LEAVE OUR REGION STILL
WITHIN THE WARM SECTOR WITH OVERNIGHT LOWS REMAINING IN THE 70S.
WITH WARM TEMPERATURES THROUGH 1 AM EDT...SOME OF OUR CLIMATE
SITES MAY SET NOT ONLY DAILY...BUT NEAR MONTHLY RECORD HIGH
MINIMUMS.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
THE MAIN STORY THIS WEEKEND WILL BE THE PASSAGE OF A COLD FRONT THAT
WILL BREAK THE HEAT WAVE THE REGION HAS BEEN EXPERIENCING OF LATE
AND USHER IN A RETURN TO MUCH MORE SEASONABLE TEMPERATURES. AS WE
OPEN THE WEEKEND SATURDAY MORNING HOWEVER...SHOWERS AND
THUNDERSTORMS ASSOCIATED WITH THE PRE-FRONTAL TROUGH WILL STILL
LIKELY BE CROSSING THE FORECAST AREA. THIS INITIAL BATCH OF
CONVECTIVE ACTIVITY SHOULD TAPER OFF FROM NORTHWEST TO SOUTHEAST
DURING THE MORNING HOURS WITH THE PASSAGE OF THE TROUGH...HOWEVER A
SECOND ROUND OF SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AGAIN
DURING THE AFTERNOON/EARLY EVENING HOURS ACCOMPANYING THE PASSAGE OF
THE ACTUAL COLD FRONT. WITH THE LOW LEVEL JET WELL TO OUR EAST AND
MODEL CAPES ONLY IN THE 500-1000 J/KG RANGE...ANY SHOWERS AND
THUNDERSTORMS THAT DO OCCUR SHOULD REMAIN RELATIVELY BENIGN. THE
COMBINATION OF CLOUD COVER AND THE GRADUAL FILTERING OF COOLER AIR
INTO THE REGION BEHIND THE PRE-FRONTAL TROUGH MEANS THAT MOST AREAS
SHOULD ONLY TOP OUT IN THE LOWER 80S...THOUGH AREAS SOUTHEAST OF
LAKE ONTARIO COULD STILL SEE HIGHS IN THE MID 80S THANKS TO
DOWNSLOPING SOUTHWESTERLY FLOW AHEAD OF THE COLD FRONT.
THE COLD FRONT WILL CROSS WESTERN/NORTH CENTRAL NEW YORK SATURDAY
EVENING BRINGING AN END TO ANY LINGERING PRECIPITATION AS MUCH
COOLER AND DRIER AIR ADVECTS INTO THE REGION. WITH THE MUCH
ANTICIPATED ARRIVAL OF THIS AIRMASS LOOK FOR TEMPERATURES TO DIP
INTO THE MID 50S ACROSS THE NORTH COUNTRY AND SOUTHERN TIER WHILE
THE LAKE PLAINS AND FINGER LAKES WILL COOL INTO THE LOWER 60S. THE
COOLING TEMPERATURES COMBINED WITH ANY LINGERING MOISTURE FROM
FRIDAY NIGHT/SATURDAY/S RAINFALL COULD LEAD TO PATCHY FOG ACROSS THE
SOUTHERN TIER.
DRY AND MILD WEATHER WILL PREVAIL ON SUNDAY AND SUNDAY NIGHT AS HIGH
PRESSURE SETTLES OVER THE GREAT LAKES IN THE WAKE OF THE COLD FRONT.
HIGHS IN THE MID TO UPPER 70S ON SUNDAY WILL PROVIDE A REFRESHING
BREAK FROM THE RECENT HEAT. WHILE MOST AREAS SHOULD SEE PLENTY OF
SUNSHINE...WITH 850MB TEMPERATURES COOLING TO THE +8 TO +10C RANGE
AND LAKE TEMPERATURES RUNNING A TOASTY +25C...CANNOT RULE OUT THE
POSSIBILITY OF SOME LAKE INDUCED CLOUD COVER CREEPING INTO WESTERN
NEW YORK. ANY LAKE INDUCED CLOUD COVER SHOULD DIMINISH SUNDAY
EVENING AS WINDS VEER TO TO THE EAST...HOWEVER EXPECT MID/HIGH
CLOUDS TO MOVE IN FROM THE WEST LATER SUNDAY NIGHT AHEAD OF A WEAK
SHORTWAVE CROSSING THE CENTRAL GREAT LAKES.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
BY MONDAY HIGH PRESSURE WILL DRIFT OFF THE NEW ENGLAND COAST...
ALLOWING SOUTHERLY RETURN FLOW TO BEGIN. MODELS CONTINUE TO BE A
LITTLE MORE AGGRESSIVE IN BRINGING A PLUME OF DEEPER MOISTURE AND
PERHAPS A FEW SHOWERS INTO EASTERN PA AND NY...BUT IT STILL APPEARS
THIS WILL REMAIN MAINLY TO OUR EAST. HAVE CONTINUED WITH A DRY
FORECAST FOR MONDAY WITH TEMPERATURES MODERATING TO VERY CLOSE TO
AVERAGE.
TUESDAY THROUGH THURSDAY A BROAD TROUGH WILL SLOWLY EVOLVE IN THE
GREAT LAKES. NUMEROUS SHORTWAVE FEATURES WILL ROTATE THROUGH THE
DEVELOPING TROUGH...BUT MODEL GUIDANCE REMAINS OUT OF PHASE WITH
RESPECT TO TIMING AND AMPLITUDE OF THESE FEATURES. AT THIS POINT
HAVE JUST BLANKETED THE PERIOD WITH LOW CHANCE POPS UNTIL BETTER
MODEL AGREEMENT ALLOWS FOR MORE REFINED TIMING. TEMPERATURES WILL
RETURN TO A LITTLE ABOVE AVERAGE AND HUMIDITY WILL INCREASE...BUT
BOTH WILL REMAIN BELOW THE LEVELS OF THIS WEEK.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
VFR FLIGHT CONDITIONS WERE FOUND AT 12Z ACROSS THE REGION...AND
THESE CONDITIONS SHOULD PREVAIL THROUGH MUCH OF THE FIRST 12 TO 18
HOURS OF THIS TAF CYCLE.
THE PRESSURE GRADIENT WILL INCREASE TODAY IN ADVANCE OF AN
APPROACHING COLD FRONT SAGGING SOUTHWARD ACROSS ONTARIO PROVINCE...
WHICH WILL RESULT IN RATHER BREEZY TO WINDY CONDITIONS DEVELOPING
ACROSS THE AREA DURING THE MORNING...THEN CONTINUING THROUGH THE
AFTERNOON. EXPECT SOUTHWESTERLY SURFACE WINDS TO INCREASE TO 15-25
KTS WITH GUSTS TO AS HIGH AS 35-40 KTS BY LATE MORNING/EARLY
AFTERNOON...WITH THE STRONGEST WINDS MOST LIKELY DOWNWIND OF LAKE
ERIE FROM KBUF/KIAG OVER TO KROC.
WITH THE DEVELOPING STRONGER SOUTHWESTERLY FLOW...LAKE SHADOWS WILL
QUICKLY DEVELOP AND SPREAD ACROSS MUCH OF THE AREA THIS AFTERNOON...
THEREBY LIMITING ANY POTENTIAL FOR CONVECTION TO FAR SOUTHERN
PORTIONS OF THE SOUTHERN TIER/FINGER LAKES AND INTERIOR PORTIONS OF
THE NORTH COUNTRY FOR THE VAST MAJORITY OF THE DAY. THROUGH THE
EVENING HOURS CONVECTION WILL BEGIN TO EDGE INTO WNY AS WELL AS THE
NORTH COUNTRY. EXPECT CONDITIONS TO DROP TO MVFR OVERNIGHT AS
THE RAIN SHOWERS PRESS SOUTHEASTWARD ACROSS THE EASTERN GREAT LAKES
REGION. WITH INSTABILITY REMAINING THERE WILL ALSO LIKELY BE
THUNDERSTORMS ACCOMPANYING THE PRECIPITATION. RAIN SHOWERS WITH
THUNDERSTORMS WILL THEN CONTINUE TO FALL THROUGH THE END OF THE TAF
CYCLE. ANY OF THESE STORMS COULD BEING BRIEF PERIODS OF IFR FLIGHT
CONDITIONS.
OUTLOOK...
SATURDAY...A PERIOD OF SHOWERS AND THUNDERSTORMS IS LIKELY WITH
ASSOCIATED IFR/MVFR...WITH MAINLY VFR CONDITIONS OTHERWISE.
SUNDAY AND MONDAY...VFR.
TUESDAY...MAINLY VFR WITH A CHANCE OF SHOWERS/THUNDERSTORMS.
&&
.MARINE...
AN INCREASING PRESSURE GRADIENT WILL BRING GUSTY SOUTHWEST WINDS
TODAY TO THE LAKES...ESPECIALLY LAKE ERIE AND ACROSS BOTH RIVERS.
WINDS AND WAVES WILL BUILD TO SMALL CRAFT ADVISORY LEVELS THROUGH
THE DAY TODAY...THEN LINGER AT THESE LEVELS THROUGH TONIGHT/EARLY
SATURDAY. WILL CONTINUE WITH SMALL CRAFT ADVISORIES FOR ALL
NEARSHORE WATERS OF LAKES ERIE AND ONTARIO...AS WELL AS THE NIAGARA
RIVER AND SAINT LAWRENCE RIVER.
A GREATER AND MORE WIDESPREAD SHOWER AND THUNDERSTORM CHANCES WILL
ARRIVE FOR TONIGHT AS A COLD FRONT MAKES ITS WAY ACROSS THE LOWER
LAKES...BRINGING THE POTENTIAL FOR STRONGER TO POTENTIALLY SEVERE
STORMS WITH LOCALLY STRONG WINDS AND HIGHER WAVES.
CONDITIONS WILL RETURN TO BELOW SCA LATER ON SATURDAY AND REMAIN
BELOW SCA THROUGH THE REMAINDER OF THE WEEKEND AND INTO THE
BEGINNING OF NEXT WEEK.
&&
.CLIMATE...
HOT AND HUMID WEATHER WILL CONTINUE THROUGH TODAY AND TEMPERATURES
WILL APPROACH RECORD HIGHS THIS AFTERNOON...THOUGH THE ONLY SITE
THAT IS EXPECTED TO AT LEAST TIE IT/S RECORD HIGH IS ROCHESTER.
HOWEVER...WITH READINGS IN THE UPPER 70S THIS FRIDAY MORNING...RECORD
WARM LOWS SHOULD BE BROKEN AT ALL THREE LOCATIONS BELOW.
HERE ARE THE RECORDS FOR THE REMAINDER OF THE WORK WEEK.
BUFFALO..
DATE RECORD HIGH RECORD WARM LOW
FRI 7/19 92 75
ROCHESTER..
DATE RECORD HIGH RECORD WARM LOW
FRI 7/19 95 75
WATERTOWN..
DATE RECORD HIGH RECORD WARM LOW
FRI 7/19 92 72
HERE ARE THE MONTHLY AND ALL TIME RECORD LOW MINIMUMS...
BUFFALO..
JULY.. 78 1897
ALL TIME.. 79 2006
ROCHESTER..
JULY (ALL TIME)..81 1936 AND 1940
WATERTOWN..
JULY (ALL TIME).. 79 2011
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ001>006-011-
013-014.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ001-002-010-
011-019-085.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR LEZ020.
SMALL CRAFT ADVISORY UNTIL 10 AM EDT SATURDAY FOR LEZ040-
041.
SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR
LOZ030.
SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR LOZ042-
043.
SMALL CRAFT ADVISORY UNTIL 10 AM EDT SATURDAY FOR LOZ044-
045.
SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR
SLZ022-024.
&&
$$
SYNOPSIS...THOMAS
NEAR TERM...APFFEL/THOMAS
SHORT TERM...WOOD
LONG TERM...HITCHCOCK
AVIATION...THOMAS
MARINE...THOMAS
CLIMATE...HITCHCOCK/WOOD/THOMAS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
150 PM EDT FRI JUL 19 2013
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL EXTEND INTO THE AREA THROUGH SATURDAY. A
COLD FRONT WILL APPROACH THE CAROLINAS ON SUNDAY AND THEN STALL
ACROSS THE REGION THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1020 AM FRIDAY...
12Z SOUNDINGS FROM AROUND THE AREA SHOWED A MODEST CAP AROUND 700MB
AT KMHX...WITH THE CAP AT THAT LEVEL MUCH WEAKER TOWARD KGSO GIVEN
TEMPERATURES 2C TO 3C COOLER. THE LATEST RUC INDICATES GENERAL
SUBSIDENCE OVER CENTRAL NORTH CAROLINA THIS AFTERNOON...WITH WEAK
WINDS ALOFT AND THE MOST FAVORABLE ITEMS FOR ANY RELATIVELY DEEP
LIFT BEING THE SURFACE TROUGH LINGERING OVER THE WESTERN PIEDMONT...
COUPLED WITH A WEAK 850MB TROUGH IN THE SAME AREA AND AVAILABLE
LOW-LEVEL MOISTURE. OVERALL MOISTURE SHOULD BE BEST TOWARD THE
NORTHWEST PIEDMONT LATER THIS AFTERNOON WHERE HIGHER 850MB THETA-E
VALUES ARE FORECAST. IT IS ALSO IN THAT LOCATION WHERE THE BETTER
1000-500MB LAPSE RATES ARE FORECAST...NEAR 6.75C/KM...AND WHERE THE
BETTER INSTABILITY LIES...2000-2500J/KG VERSUS A FORECAST OF ONLY
1000-1500J/KG TOWARD THE COASTAL PLAIN. CONVECTION-ALLOWING
MODELS...GIVEN THE GENERAL SUBSIDENCE...ARE MOSTLY RELUCTANT TO
FORECAST MUCH PRECIPITATION IN CENTRAL NORTH CAROLINA...BUT WITHIN
THE SLIGHT CHANCE RANGE...THE BETTER CHANCE SHOULD MAINLY BE ALONG
AND NORTH/WEST OF INTERSTATE 85. AS NOTED PREVIOUSLY...WEAK WINDS
ALOFT WILL ALLOW ANY OF THE ISOLATED STORMS TO MOVE ONLY VERY
SLOWLY. 1000-850MB THICKNESSES AT 12Z AND FORECAST LATE THIS
AFTERNOON ARE BASICALLY PERSISTENCE FROM THURSDAY...AND HAVE
FORECAST HIGHS CLOSE TO THOSE OF THURSDAY AS A RESULT. THIS PLACES
MOST LOCATIONS WITH HEAT INDICES AROUND 100...A COUPLE OF DEGREES
WARMER TOWARD KIXA AND KRZZ. ANY THUNDERSTORMS SHOULD DIMINISH
DIURNALLY...WITH OVERNIGHT LOWS IN THE LOWER TO MID 70S.
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 245 AM FRIDAY...
THE NORTHERN STREAM TROUGH AND ASSOCIATED SFC COLD FRONT WILL REMAIN
NORTH OF THE AREA...SAGGING SOUTH INTO THE SOUTHERN OHIO VALLEY AND
NORTHERN MID-ATLANTIC STATES BY SUNDAY MORNING. NOT MANY DIFFERENCES
BETWEEN TODAY AND SATURDAY WITH THE SAME MESOSCALE FORCING DRIVING
ISOLATED TO SCATTERED DIURNAL CONVECTION SATURDAY AFTERNOON
HIGHS IN THE LOWER 90S. LOWS IN THE LOWER TO MID 70S.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
AS OF 150 PM FRIDAY...
SUNDAY AND MONDAY...
THE BACKDOOR COLD FRONT OVER THE OHIO VALLEY WILL BE SLOW TO EDGE
SOUTH AND IS EXPECTED TO STALL NORTH OF THE AREA SUNDAY AND MONDAY
AS IT ALIGNS PARALLEL TO THE FLOW ALONG THE LOW AMPLITUDE UPPER
TROF. TANGIBLE DISTURBANCES IN THE LARGER FLOW REGIME ARE NOT
READILY EVIDENT AT THIS TIME...BUT MOISTURE AND INSTABILITY WILL BE
MORE THAN ADEQUATE FOR SUPPORT OF MAINLY DIURNAL CONVECTION. WILL
CONTINUE POPS IN THE 50-60 PERCENT RANGE BOTH DAYS. SMALL HEIGHT
FALLS AND REDUCED INSOLATION WILL TAKE THE EDGE OFF OUR HIGH
TEMPERATURES...AND HIGHS BOTH DAYS WILL BE SLIGHTLY COOLER THAN
NORMAL...IN THE 85 TO 90 RANGE.
TUESDAY THROUGH FRIDAY...
VERY SLOW EASTWARD TRANSLATION AND DEEPENING OF THE UPPER TROF TO
OUR WEST WILL KEEP US IN AN UNSETTLED PATTERN THROUGH AT LEAST
THURSDAY. THE STALLED FRONT NORTH OF THE AREA BECOMES MORE DIFFUSE
WITH TIME... MEANWHILE THE PERSISTENT LEE TROF ALONG THE EASTERN
SEABOARD SHARPENS IN STRENGTHENING SOUTHWEST FLOW AHEAD OF THE
DEEPENING UPPER TROF. THE PROBABILITY OF PRECIP WILL REMAIN ABOVE
NORMAL ACROSS THE AREA AS THE NEAR STAGNANT AIRMASS WILL REQUIRE
LITTLE FORCING TO GENERATE CONVECTION...ITS THE DISTRIBUTION AND
TIMING WHICH WILL REMAIN LOW CONFIDENCE. THAT SAID...WILL HAVE 40-50
POPS TUE THROUGH FRI...AGAIN FOCUSING ON MAX DIURNAL HEATING...WITH
PERSISTENCE HIGHS FROM 85-90. THE UPPER TROF MAY MAKE ITS MOVE EAST
ACROSS THE AREA LATE THIS WEEK...WHICH WOULD ENHANCE AS WELL AS
PROVIDE ORGANIZATION FOR CONVECTION IN THE LATE THURSDAY OR FRIDAY
TIME FRAME...AS WELL AS INITIATE A DRYING TREND FOR THE UPCOMING
WEEKEND...WE SHALL SEE.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AS OF 1205 PM FRIDAY...
VFR CONDITIONS ARE CURRENTLY BEING REPORTED ACROSS MOST OF CENTRAL
NC. THIS IS EXPECTED TO REMAIN THE CASE THROUGH THE 24 HOUR TAF
PERIOD...WITH THE EXCEPTION OF A FEW ISOLD TSTMS DURING THE REST OF
THIS AFTERNOON AND EARLY EVENING THAT MAY BRIEFLY REDUCE FLT
CONDITIONS TO MVFR.
BEYOND THE 24 HOUR TAF PERIOD:
OUTSIDE OF SOME EARLY MORNING FOG/STRATUS SATURDAY...VFR CONDITIONS
SHOULD PREVAIL WITH ONLY ISOLATED AFTERNOON STORMS. A SLOW MOVING
COLD FRONT WILL MOVE INTO THE AREA FROM THE NORTHWEST ON SUNDAY AND
WILL STALL ACROSS THE AREA THROUGH EARLY NEXT WEEK. THIS WILL RESULT
IN NUMEROUS SHOWERS AND THUNDERSTORMS...ESPECIALLY DURING THE
AFTERNOON AND EVENING HOURS...WITH SUB VFR CONDITIONS IN HEAVY RAIN.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CBL
NEAR TERM...CBL/DJF
SHORT TERM...CBL
LONG TERM...MLM
AVIATION...NP/CBL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1205 PM EDT FRI JUL 19 2013
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL EXTEND INTO THE AREA THROUGH SATURDAY. A
COLD FRONT WILL APPROACH THE CAROLINAS ON SUNDAY AND THEN STALL
ACROSS THE REGION THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1020 AM FRIDAY...
12Z SOUNDINGS FROM AROUND THE AREA SHOWED A MODEST CAP AROUND 700MB
AT KMHX...WITH THE CAP AT THAT LEVEL MUCH WEAKER TOWARD KGSO GIVEN
TEMPERATURES 2C TO 3C COOLER. THE LATEST RUC INDICATES GENERAL
SUBSIDENCE OVER CENTRAL NORTH CAROLINA THIS AFTERNOON...WITH WEAK
WINDS ALOFT AND THE MOST FAVORABLE ITEMS FOR ANY RELATIVELY DEEP
LIFT BEING THE SURFACE TROUGH LINGERING OVER THE WESTERN PIEDMONT...
COUPLED WITH A WEAK 850MB TROUGH IN THE SAME AREA AND AVAILABLE
LOW-LEVEL MOISTURE. OVERALL MOISTURE SHOULD BE BEST TOWARD THE
NORTHWEST PIEDMONT LATER THIS AFTERNOON WHERE HIGHER 850MB THETA-E
VALUES ARE FORECAST. IT IS ALSO IN THAT LOCATION WHERE THE BETTER
1000-500MB LAPSE RATES ARE FORECAST...NEAR 6.75C/KM...AND WHERE THE
BETTER INSTABILITY LIES...2000-2500J/KG VERSUS A FORECAST OF ONLY
1000-1500J/KG TOWARD THE COASTAL PLAIN. CONVECTION-ALLOWING
MODELS...GIVEN THE GENERAL SUBSIDENCE...ARE MOSTLY RELUCTANT TO
FORECAST MUCH PRECIPITATION IN CENTRAL NORTH CAROLINA...BUT WITHIN
THE SLIGHT CHANCE RANGE...THE BETTER CHANCE SHOULD MAINLY BE ALONG
AND NORTH/WEST OF INTERSTATE 85. AS NOTED PREVIOUSLY...WEAK WINDS
ALOFT WILL ALLOW ANY OF THE ISOLATED STORMS TO MOVE ONLY VERY
SLOWLY. 1000-850MB THICKNESSES AT 12Z AND FORECAST LATE THIS
AFTERNOON ARE BASICALLY PERSISTENCE FROM THURSDAY...AND HAVE
FORECAST HIGHS CLOSE TO THOSE OF THURSDAY AS A RESULT. THIS PLACES
MOST LOCATIONS WITH HEAT INDICES AROUND 100...A COUPLE OF DEGREES
WARMER TOWARD KIXA AND KRZZ. ANY THUNDERSTORMS SHOULD DIMINISH
DIURNALLY...WITH OVERNIGHT LOWS IN THE LOWER TO MID 70S.
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 245 AM FRIDAY...
THE NORTHERN STREAM TROUGH AND ASSOCIATED SFC COLD FRONT WILL REMAIN
NORTH OF THE AREA...SAGGING SOUTH INTO THE SOUTHERN OHIO VALLEY AND
NORTHERN MID-ATLANTIC STATES BY SUNDAY MORNING. NOT MANY DIFFERENCES
BETWEEN TODAY AND SATURDAY WITH THE SAME MESOSCALE FORCING DRIVING
ISOLATED TO SCATTERED DIURNAL CONVECTION SATURDAY AFTERNOON
HIGHS IN THE LOWER 90S. LOWS IN THE LOWER TO MID 70S.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 230 AM FRIDAY...
SUNDAY THROUGH THURSDAY:
THIS PERIOD WILL BE DOMINATED BY A SURFACE TROUGH/FRONTAL BOUNDARY
STALLING OVER THE MID ATLANTIC...WITH THE UPPER LEVEL TROUGH DIGGING
SOUTH INTO CENTRAL NC. GOOD MOISTURE ADVECTION FROM THE GULF IN
SOUTHWEST FLOW ALONG THE TROUGH AXIS WILL MOISTEN THE COLUMN...WITH
PW`S AROUND TWO INCHES FORECAST THROUGH TUESDAY NIGHT. DISTURBANCES
TRACKING OVER THE AREA ALONG THE BASE OF THE MID/UPPER TROUGH WILL
BE SUFFICIENT TO INITIATE CONVECTION...ESPECIALLY DURING THE
AFT/EVE...GIVEN THE MOIST AND UNSTABLE AIRMASS IN PLACE. CONFIDENCE
ON EXACTLY WHERE THE BEST CHANCES/COVERAGE OF SHOWERS AND STORMS
WILL OCCUR IS STILL LOW GIVEN THE UNCERTAINTY OF WHERE THE FRONT
WILL STALL. FOR NOW WILL CONTINUE TO CARRY AT LEAST A CHANCE OF
SHOWERS AND STORMS THROUGH THE PERIOD...WITH HIGHEST CHANCES DURING
THE AFT/EVE. WITH THE CURRENT CHANCES OF CONVECTION AND GIVEN THE
INCREASE IN MOISTURE EXPECTED...CLOUDY CONDITIONS WILL BE LIKELY
OVER CENTRAL NC DURING THIS TIME. TAKING CLOUDS AND PRECIP INTO
ACCOUNT...HIGH TEMPS IN THE MID 80S TO NEAR 90 DEGREES AND OVERNIGHT
LOWS IN THE UPPER 60S TO LOW 70S ARE EXPECTED THROUGH THE PERIOD.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AS OF 1205 PM FRIDAY...
VFR CONDITIONS ARE CURRENTLY BEING REPORTED ACROSS MOST OF CENTRAL
NC. THIS IS EXPECTED TO REMAIN THE CASE THROUGH THE 24 HOUR TAF
PERIOD...WITH THE EXCEPTION OF A FEW ISOLD TSTMS DURING THE REST OF
THIS AFTERNOON AND EARLY EVENING THAT MAY BRIEFLY REDUCE FLT
CONDITIONS TO MVFR.
BEYOND THE 24 HOUR TAF PERIOD:
OUTSIDE OF SOME EARLY MORNING FOG/STRATUS SATURDAY...VFR CONDITIONS
SHOULD PREVAIL WITH ONLY ISOLATED AFTERNOON STORMS. A SLOW MOVING
COLD FRONT WILL MOVE INTO THE AREA FROM THE NORTHWEST ON SUNDAY AND
WILL STALL ACROSS THE AREA THROUGH EARLY NEXT WEEK. THIS WILL RESULT
IN NUMEROUS SHOWERS AND THUNDERSTORMS...ESPECIALLY DURING THE
AFTERNOON AND EVENING HOURS...WITH SUB VFR CONDITIONS IN HEAVY RAIN.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CBL
NEAR TERM...CBL/DJF
SHORT TERM...CBL
LONG TERM...KC
AVIATION...NP/CBL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1020 AM EDT FRI JUL 19 2013
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL EXTEND INTO THE AREA THROUGH SATURDAY. A
COLD FRONT WILL APPROACH THE CAROLINAS ON SUNDAY AND THEN STALL
ACROSS THE REGION THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1020 AM FRIDAY...
12Z SOUNDINGS FROM AROUND THE AREA SHOWED A MODEST CAP AROUND 700MB
AT KMHX...WITH THE CAP AT THAT LEVEL MUCH WEAKER TOWARD KGSO GIVEN
TEMPERATURES 2C TO 3C COOLER. THE LATEST RUC INDICATES GENERAL
SUBSIDENCE OVER CENTRAL NORTH CAROLINA THIS AFTERNOON...WITH WEAK
WINDS ALOFT AND THE MOST FAVORABLE ITEMS FOR ANY RELATIVELY DEEP
LIFT BEING THE SURFACE TROUGH LINGERING OVER THE WESTERN PIEDMONT...
COUPLED WITH A WEAK 850MB TROUGH IN THE SAME AREA AND AVAILABLE
LOW-LEVEL MOISTURE. OVERALL MOISTURE SHOULD BE BEST TOWARD THE
NORTHWEST PIEDMONT LATER THIS AFTERNOON WHERE HIGHER 850MB THETA-E
VALUES ARE FORECAST. IT IS ALSO IN THAT LOCATION WHERE THE BETTER
1000-500MB LAPSE RATES ARE FORECAST...NEAR 6.75C/KM...AND WHERE THE
BETTER INSTABILITY LIES...2000-2500J/KG VERSUS A FORECAST OF ONLY
1000-1500J/KG TOWARD THE COASTAL PLAIN. CONVECTION-ALLOWING
MODELS...GIVEN THE GENERAL SUBSIDENCE...ARE MOSTLY RELUCTANT TO
FORECAST MUCH PRECIPITATION IN CENTRAL NORTH CAROLINA...BUT WITHIN
THE SLIGHT CHANCE RANGE...THE BETTER CHANCE SHOULD MAINLY BE ALONG
AND NORTH/WEST OF INTERSTATE 85. AS NOTED PREVIOUSLY...WEAK WINDS
ALOFT WILL ALLOW ANY OF THE ISOLATED STORMS TO MOVE ONLY VERY
SLOWLY. 1000-850MB THICKNESSES AT 12Z AND FORECAST LATE THIS
AFTERNOON ARE BASICALLY PERSISTENCE FROM THURSDAY...AND HAVE
FORECAST HIGHS CLOSE TO THOSE OF THURSDAY AS A RESULT. THIS PLACES
MOST LOCATIONS WITH HEAT INDICES AROUND 100...A COUPLE OF DEGREES
WARMER TOWARD KIXA AND KRZZ. ANY THUNDERSTORMS SHOULD DIMINISH
DIURNALLY...WITH OVERNIGHT LOWS IN THE LOWER TO MID 70S.
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 245 AM FRIDAY...
THE NORTHERN STREAM TROUGH AND ASSOCIATED SFC COLD FRONT WILL REMAIN
NORTH OF THE AREA...SAGGING SOUTH INTO THE SOUTHERN OHIO VALLEY AND
NORTHERN MID-ATLANTIC STATES BY SUNDAY MORNING. NOT MANY DIFFERENCES
BETWEEN TODAY AND SATURDAY WITH THE SAME MESOSCALE FORCING DRIVING
ISOLATED TO SCATTERED DIURNAL CONVECTION SATURDAY AFTERNOON
HIGHS IN THE LOWER 90S. LOWS IN THE LOWER TO MID 70S.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 230 AM FRIDAY...
SUNDAY THROUGH THURSDAY:
THIS PERIOD WILL BE DOMINATED BY A SURFACE TROUGH/FRONTAL BOUNDARY
STALLING OVER THE MID ATLANTIC...WITH THE UPPER LEVEL TROUGH DIGGING
SOUTH INTO CENTRAL NC. GOOD MOISTURE ADVECTION FROM THE GULF IN
SOUTHWEST FLOW ALONG THE TROUGH AXIS WILL MOISTEN THE COLUMN...WITH
PW`S AROUND TWO INCHES FORECAST THROUGH TUESDAY NIGHT. DISTURBANCES
TRACKING OVER THE AREA ALONG THE BASE OF THE MID/UPPER TROUGH WILL
BE SUFFICIENT TO INITIATE CONVECTION...ESPECIALLY DURING THE
AFT/EVE...GIVEN THE MOIST AND UNSTABLE AIRMASS IN PLACE. CONFIDENCE
ON EXACTLY WHERE THE BEST CHANCES/COVERAGE OF SHOWERS AND STORMS
WILL OCCUR IS STILL LOW GIVEN THE UNCERTAINTY OF WHERE THE FRONT
WILL STALL. FOR NOW WILL CONTINUE TO CARRY AT LEAST A CHANCE OF
SHOWERS AND STORMS THROUGH THE PERIOD...WITH HIGHEST CHANCES DURING
THE AFT/EVE. WITH THE CURRENT CHANCES OF CONVECTION AND GIVEN THE
INCREASE IN MOISTURE EXPECTED...CLOUDY CONDITIONS WILL BE LIKELY
OVER CENTRAL NC DURING THIS TIME. TAKING CLOUDS AND PRECIP INTO
ACCOUNT...HIGH TEMPS IN THE MID 80S TO NEAR 90 DEGREES AND OVERNIGHT
LOWS IN THE UPPER 60S TO LOW 70S ARE EXPECTED THROUGH THE PERIOD.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
AS OF 1020 AM FRIDAY...
VFR CONDITIONS WILL PREVAIL OUTSIDE OF ANY AFTERNOON AND EVENING
SHOWER OR THUNDERSTORM. DEEP CONVECTIVE COVERAGE THIS AFTERNOON AND
EVENING IS EXPECTED TO BE RATHER ISOLATED AND THUS HAVE OMITTED ANY
MENTION OF SHOWERS OR THUNDER FROM ALL TAF SITES.
BEYOND THE 24 HOUR TAF PERIOD:
OUTSIDE OF SOME EARLY MORNING FOG/STRATUS SATURDAY...VFR CONDITIONS
SHOULD PREVAIL WITH ONLY ISOLATED AFTERNOON STORMS. A SLOW MOVING
COLD FRONT WILL MOVE INTO THE AREA FROM THE NORTHWEST ON SUNDAY AND
WILL STALL ACROSS THE AREA THROUGH EARLY NEXT WEEK. THIS WILL RESULT
IN NUMEROUS SHOWERS AND THUNDERSTORMS...ESPECIALLY DURING THE
AFTERNOON AND EVENING HOURS...WITH SUB VFR CONDITIONS IN HEAVY RAIN.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CBL
NEAR TERM...CBL/DJF
SHORT TERM...CBL
LONG TERM...KC
AVIATION...CBL/DJF
AREA FORECAST DISCUSSION
NWS BISMARCK ND
834 PM CDT SAT JUL 20 2013
.UPDATE...
ISSUED AT 834 PM CDT SAT JUL 20 2013
LATEST REGIONAL RADAR SHOWS AN AREA OF SEVERE THUNDERSTORMS IN
EASTERN MONTANA MOVING SOUTHEAST WITH TIME. MONITORING FOR ANY
OUTFLOWS...WITH CURRENT MOVEMENT INDICATING THAT THIS AREA COULD
MOVE INTO OUR FAR SOUTHWESTERN COUNTIES OF GOLDEN VALLEY/SLOPE/BOWMAN
IN THE NEXT COUPLE OF HOURS. OTHERWISE EXPECT ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS OVERNIGHT...WITH INCREASING WARM AIR
ADVECTION ASSOCIATED WITH A WARM FRONT OVER EASTERN MONTANA. STILL
SOME ISOLATED CONVECTION IN NORTHWESTERN SOUTH DAKOTA BUT NOTHING
SEVERE AT THIS TIME. MINOR CHANGES FROM PREVIOUS FORECAST.
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 BISMARCK ND
1150 AM CDT FRI JUL 19 2013
.UPDATE...
ISSUED AT 1138 AM CDT FRI JUL 19 2013
LATE THIS MORNING...THE VISIBLE SATELLITE LOOP SHOWS A CLUSTER OF
SHOWERS NEAR REGINA SASKATCHEWAN...MOVING SOUTHEAST. OTHERWISE
JUST A FEW CLOUDS WERE ALONG THE NORTH DAKOTA - CANADIAN BORDER.
CURRENT THINKING STILL ASSUMES THE SHOWERS ASSOCIATED WITH A COLD
FRONTAL BOUNDARY MOVING THROUGH SOUTHERN CANADA WILL TRACK
INTO/DEVELOP ACROSS THE NORTHWEST LATE THIS AFTERNOON. OTHERWISE
MOSTLY SUNNY SKIES AND COOLER AND DRIER WEATHER FORECAST THROUGH
TODAY. CURRENT FORECAST LOOKING GOOD.
UPDATE ISSUED AT 932 AM CDT FRI JUL 19 2013
FRIDAY MORNING...THE CURRENT WEATHER CONDITIONS WERE DEFINED BY A
POST FRONTAL ENVIRONMENT WITH MOSTLY CLEAR SKIES AND LIGHT
NORTHWEST WINDS. THIS UPDATE WILL BE MAINLY TO PROVIDE CURRENT
TEMPERATURES AND RELATIVE HUMIDITY. THIS AFTERNOON...ANOTHER
FRONTAL SYSTEM WILL APPROACH FROM THE NORTHWEST AND BRING A SLIGHT
CHANCE FOR THUNDERSTORMS. CURRENT FORECAST LOOKS GOOD IN THIS
REGARD.
UPDATE ISSUED AT 627 AM CDT FRI JUL 19 2013
NO SIGNIFICANT CHANGES TO THE CURRENT FORECAST. CLEAR SKIES ACROSS
WESTERN AND CENTRAL NORTH DAKOTA EARLY THIS MORNING SO LOWERED
CLOUD COVER THIS MORNING ACROSS THE NORTH. DO EXPECT INCREASING
CLOUDS NORTH BY MID MORNING WITH SHOWER AND THUNDERSTORM CHANCES
HOLDING OFF UNTIL AFTERNOON.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM CDT FRI JUL 19 2013
THE HIGHLIGHT OF THE SHORT TERM IS THE CONVECTIVE POTENTIAL THIS
AFTERNOON THROUGH TONIGHT.
AS OF 0830 UTC...A COLD FRONT WAS ANALYZED FROM NORTHEAST
MANITOBA...ARCHING SOUTHWEST ACROSS NORTHERN LAKE WINNIPEG AND
INTO CENTRAL SASKATCHEWAN. THIS FRONT IS FORECAST TO CONTINUE TO
PROPAGATE SOUTH TODAY...CROSSING INTO THE NORTHERN PORTIONS OF
NORTH DAKOTA BY 20-22 UTC. THIS FEATURE WILL BE THE FOCUS FOR
CONVECTIVE DEVELOPMENT LATE THIS AFTERNOON AND THROUGH THE
NIGHT. THE 00 UTC 4 KM WRF AND 06 UTC HRRR SUGGEST SURFACE BASED
CONVECTION ENTERING NORTH DAKOTA WITHIN THE 20-22 UTC TIME FRAME
AND PROPAGATING SOUTH THROUGH THE EVENING AND OVERNIGHT WITH THE
FRONT. CANNOT RULE OUT AN ISOLATED LOW END SEVERE STORM GIVEN ML
CAPE VALUES AROUND 1000 J/KG AND DEEP LAYER SHEAR OF 40 KTS.
HOWEVER...GIVEN WEAK UPPER LEVEL FORCING...THE THREAT SEEMS
MARGINAL WITH WESTERN AND CENTRAL NORTH DAKOTA ONLY IN GENERAL
THUNDER IN THE SPC DAY 1 OUTLOOK. THERE IS SOME UNCERTAINTY AS TO
HOW LONG AFTER SUNSET CONVECTION CAN SUSTAIN ITSELF...WITH WEAK
UPPER LEVEL FORCING AND THE LACK OF A LOW LEVEL JET. THE 00 UTC
DETERMINISTIC SUITE SUGGESTS ISOLATED TO SCATTERED CONVECTION
CONTINUING IN THE VICINITY OF THE FRONT THROUGH THE NIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 352 AM CDT FRI JUL 19 2013
THE LONG TERM PERIOD WILL CONSIST OF A NORTHWEST UPPER FLOW PATTERN
WITH IMPULSES TRANSLATING THROUGH THE POLAR JET AND AFFECTING THE
LOCAL AREA ABOUT EVERY 18-24 HOURS THROUGH THE ENTIRE PERIOD. THIS
WILL RESULT IN A SEASONABLE TEMPERATURE REGIME WITH DAYTIME HIGHS
MAINLY IN THE MID 70S NORTHEAST TO THE MID 80S SOUTHWEST...AND
OVERNIGHT LOWS IN THE MID 50S TO LOWER 60S. FOR PRECIPITATION...A
MODEL BLEND WAS UTILIZED DUE TO THE UNCERTAINTY OF TIMING AND
PLACEMENT OF INDIVIDUAL IMPULSES MOVING THROUGH THE MEAN UPPER LEVEL
FLOW.
ON SATURDAY...SURFACE HIGH PRESSURE TO OUR NORTH AND EAST WILL
RESULT IN A COOLER EASTERLY FLOW. 00 UTC FRI 19 JULY NAM/GFS
FORECAST SOUNDINGS FOR SATURDAY INDICATE A STABLE ATMOSPHERE OVER
CENTRAL NORTH DAKOTA WITH MID LEVEL SHORTWAVE ENERGY PRODUCING
SHOWERS. THE WEST APPEARS TO BE THE AREA TO SEE ANY LATE MORNING
OR AFTERNOON CONVECTION. THEREFORE LIMITED CONVECTION TO AREAS WEST
OF BISMARCK AND MINOT ON SATURDAY. WE ALSO CUT BACK ON THE FORECAST
HIGHS ACROSS THE NORTHEAST THIRD OF THE CWA...WITH UPPER 60S
FORECAST FOR AREAS SUCH AS BOTTINEAU AND RUGBY. THE SOUTHWEST IS
STILL FORECAST TO CLIMB INTO THE LOWER TO MIDDLE 80S.
NO SIGNIFICANT CHANGES FROM THE MODEL BLEND SOLUTION WERE MADE TO
THE REMAINDER OF THE EXTENDED FORECAST...RESULTING IN AT LEAST A
SLIGHT CHANCE OF THUNDERSTORMS EACH DAY FOR AT LEAST A PORTION OF
THE CWA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1138 AM CDT FRI JUL 19 2013
AT 11 AM CDT...SKIES WERE MOSTLY CLEAR. VFR CONDITIONS ARE
OBSERVED AND ARE FORECAST THROUGH THE 18Z TAF PERIOD. A WEAK COLD
FRONTAL BOUNDARY ACROSS SOUTHERN CANADA WILL BE THE FOCUS FOR
ISOLATED THUNDERSTORMS ACROSS NORTHERN NORTH DAKOTA AFTER
22Z...AND ACROSS THE SOUTH AFTER 00Z. THUNDERSTORMS SHOULD BE TOO
ISOLATED TO ACCURATELY FORECAST...SO PLAN TO CONTINUE TO EXPRESS
THE THUNDERSTORM HAZARD VIA VCTY (VICINITY).
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...AYD
LONG TERM...TWH
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
944 AM CDT FRI JUL 19 2013
.UPDATE...
ISSUED AT 932 AM CDT FRI JUL 19 2013
FRIDAY MORNING...THE CURRENT WEATHER CONDITIONS WERE DEFINED BY A
POST FRONTAL ENVIRONMENT WITH MOSTLY CLEAR SKIES AND LIGHT
NORTHWEST WINDS. THIS UPDATE WILL BE MAINLY TO PROVIDE CURRENT
TEMPERATURES AND RELATIVE HUMIDITY. THIS AFTERNOON...ANOTHER
FRONTAL SYSTEM WILL APPROACH FROM THE NORTHWEST AND BRING A SLIGHT
CHANCE FOR THUNDERSTORMS. CURRENT FORECAST LOOKS GOOD IN THIS
REGARD.
UPDATE ISSUED AT 627 AM CDT FRI JUL 19 2013
NO SIGNIFICANT CHANGES TO THE CURRENT FORECAST. CLEAR SKIES ACROSS
WESTERN AND CENTRAL NORTH DAKOTA EARLY THIS MORNING SO LOWERED
CLOUD COVER THIS MORNING ACROSS THE NORTH. DO EXPECT INCREASING
CLOUDS NORTH BY MID MORNING WITH SHOWER AND THUNDERSTORM CHANCES
HOLDING OFF UNTIL AFTERNOON.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM CDT FRI JUL 19 2013
THE HIGHLIGHT OF THE SHORT TERM IS THE CONVECTIVE POTENTIAL THIS
AFTERNOON THROUGH TONIGHT.
AS OF 0830 UTC...A COLD FRONT WAS ANALYZED FROM NORTHEAST
MANITOBA...ARCHING SOUTHWEST ACROSS NORTHERN LAKE WINNIPEG AND
INTO CENTRAL SASKATCHEWAN. THIS FRONT IS FORECAST TO CONTINUE TO
PROPAGATE SOUTH TODAY...CROSSING INTO THE NORTHERN PORTIONS OF
NORTH DAKOTA BY 20-22 UTC. THIS FEATURE WILL BE THE FOCUS FOR
CONVECTIVE DEVELOPMENT LATE THIS AFTERNOON AND THROUGH THE
NIGHT. THE 00 UTC 4 KM WRF AND 06 UTC HRRR SUGGEST SURFACE BASED
CONVECTION ENTERING NORTH DAKOTA WITHIN THE 20-22 UTC TIME FRAME
AND PROPAGATING SOUTH THROUGH THE EVENING AND OVERNIGHT WITH THE
FRONT. CANNOT RULE OUT AN ISOLATED LOW END SEVERE STORM GIVEN ML
CAPE VALUES AROUND 1000 J/KG AND DEEP LAYER SHEAR OF 40 KTS.
HOWEVER...GIVEN WEAK UPPER LEVEL FORCING...THE THREAT SEEMS
MARGINAL WITH WESTERN AND CENTRAL NORTH DAKOTA ONLY IN GENERAL
THUNDER IN THE SPC DAY 1 OUTLOOK. THERE IS SOME UNCERTAINTY AS TO
HOW LONG AFTER SUNSET CONVECTION CAN SUSTAIN ITSELF...WITH WEAK
UPPER LEVEL FORCING AND THE LACK OF A LOW LEVEL JET. THE 00 UTC
DETERMINISTIC SUITE SUGGESTS ISOLATED TO SCATTERED CONVECTION
CONTINUING IN THE VICINITY OF THE FRONT THROUGH THE NIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 352 AM CDT FRI JUL 19 2013
THE LONG TERM PERIOD WILL CONSIST OF A NORTHWEST UPPER FLOW PATTERN
WITH IMPULSES TRANSLATING THROUGH THE POLAR JET AND AFFECTING THE
LOCAL AREA ABOUT EVERY 18-24 HOURS THROUGH THE ENTIRE PERIOD. THIS
WILL RESULT IN A SEASONABLE TEMPERATURE REGIME WITH DAYTIME HIGHS
MAINLY IN THE MID 70S NORTHEAST TO THE MID 80S SOUTHWEST...AND
OVERNIGHT LOWS IN THE MID 50S TO LOWER 60S. FOR PRECIPITATION...A
MODEL BLEND WAS UTILIZED DUE TO THE UNCERTAINTY OF TIMING AND
PLACEMENT OF INDIVIDUAL IMPULSES MOVING THROUGH THE MEAN UPPER LEVEL
FLOW.
ON SATURDAY...SURFACE HIGH PRESSURE TO OUR NORTH AND EAST WILL
RESULT IN A COOLER EASTERLY FLOW. 00 UTC FRI 19 JULY NAM/GFS
FORECAST SOUNDINGS FOR SATURDAY INDICATE A STABLE ATMOSPHERE OVER
CENTRAL NORTH DAKOTA WITH MID LEVEL SHORTWAVE ENERGY PRODUCING
SHOWERS. THE WEST APPEARS TO BE THE AREA TO SEE ANY LATE MORNING
OR AFTERNOON CONVECTION. THEREFORE LIMITED CONVECTION TO AREAS WEST
OF BISMARCK AND MINOT ON SATURDAY. WE ALSO CUT BACK ON THE FORECAST
HIGHS ACROSS THE NORTHEAST THIRD OF THE CWA...WITH UPPER 60S
FORECAST FOR AREAS SUCH AS BOTTINEAU AND RUGBY. THE SOUTHWEST IS
STILL FORECAST TO CLIMB INTO THE LOWER TO MIDDLE 80S.
NO SIGNIFICANT CHANGES FROM THE MODEL BLEND SOLUTION WERE MADE TO
THE REMAINDER OF THE EXTENDED FORECAST...RESULTING IN AT LEAST A
SLIGHT CHANCE OF THUNDERSTORMS EACH DAY FOR AT LEAST A PORTION OF
THE CWA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 932 AM CDT FRI JUL 19 2013
AT 9 AM CDT...VFR CONDITIONS WITH CLEAR SKIES COVERED THE REGION.
LATE THIS AFTERNOON ANOTHER WEAK COLD FRONTAL BOUNDARY WILL
APPROACH THE STATE FROM THE NORTHWEST. THE FRONT WILL BE THE
FOCUS FOR WIDELY SCATTERED THUNDERSTORMS. AT THIS TIME...TO MUCH
UNCERTAINTY TO ADD THUNDERSTORMS TO THE TAF. CURRENT 12Z TAFS
EXPRESS THE THUNDERSTORM THREAT AS VCTS (VICINITY) THUNDERSTORMS
AFTER 22Z NORTH AND AFTER 00Z SOUTH. WILL RE EVALUATE THE TIMING
FOR THE 18Z TAF ISSUANCE BUT THREAT WILL PROBABLY BE TO ISOLATED
TO ADD MORE DEFINITION THAN CURRENT TAFS EXPRESS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...AYD
LONG TERM...TWH
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
627 AM CDT FRI JUL 19 2013
.UPDATE...
ISSUED AT 627 AM CDT FRI JUL 19 2013
NO SIGNIFICANT CHANGES TO THE CURRENT FORECAST. CLEAR SKIES ACROSS
WESTERN AND CENTRAL NORTH DAKOTA EARLY THIS MORNING SO LOWERED
CLOUD COVER THIS MORNING ACROSS THE NORTH. DO EXPECT INCREASING
CLOUDS NORTH BY MID MORNING WITH SHOWER AND THUNDERSTORM CHANCES
HOLDING OFF UNTIL AFTERNOON.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM CDT FRI JUL 19 2013
THE HIGHLIGHT OF THE SHORT TERM IS THE CONVECTIVE POTENTIAL THIS
AFTERNOON THROUGH TONIGHT.
AS OF 0830 UTC...A COLD FRONT WAS ANALYZED FROM NORTHEAST
MANITOBA...ARCHING SOUTHWEST ACROSS NORTHERN LAKE WINNIPEG AND
INTO CENTRAL SASKATCHEWAN. THIS FRONT IS FORECAST TO CONTINUE TO
PROPAGATE SOUTH TODAY...CROSSING INTO THE NORTHERN PORTIONS OF
NORTH DAKOTA BY 20-22 UTC. THIS FEATURE WILL BE THE FOCUS FOR
CONVECTIVE DEVELOPMENT LATE THIS AFTERNOON AND THROUGH THE
NIGHT. THE 00 UTC 4 KM WRF AND 06 UTC HRRR SUGGEST SURFACE BASED
CONVECTION ENTERING NORTH DAKOTA WITHIN THE 20-22 UTC TIME FRAME
AND PROPAGATING SOUTH THROUGH THE EVENING AND OVERNIGHT WITH THE
FRONT. CANNOT RULE OUT AN ISOLATED LOW END SEVERE STORM GIVEN ML
CAPE VALUES AROUND 1000 J/KG AND DEEP LAYER SHEAR OF 40 KTS.
HOWEVER...GIVEN WEAK UPPER LEVEL FORCING...THE THREAT SEEMS
MARGINAL WITH WESTERN AND CENTRAL NORTH DAKOTA ONLY IN GENERAL
THUNDER IN THE SPC DAY 1 OUTLOOK. THERE IS SOME UNCERTAINTY AS TO
HOW LONG AFTER SUNSET CONVECTION CAN SUSTAIN ITSELF...WITH WEAK
UPPER LEVEL FORCING AND THE LACK OF A LOW LEVEL JET. THE 00 UTC
DETERMINISTIC SUITE SUGGESTS ISOLATED TO SCATTERED CONVECTION
CONTINUING IN THE VICINITY OF THE FRONT THROUGH THE NIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 352 AM CDT FRI JUL 19 2013
THE LONG TERM PERIOD WILL CONSIST OF A NORTHWEST UPPER FLOW PATTERN
WITH IMPULSES TRANSLATING THROUGH THE POLAR JET AND AFFECTING THE
LOCAL AREA ABOUT EVERY 18-24 HOURS THROUGH THE ENTIRE PERIOD. THIS
WILL RESULT IN A SEASONABLE TEMPERATURE REGIME WITH DAYTIME HIGHS
MAINLY IN THE MID 70S NORTHEAST TO THE MID 80S SOUTHWEST...AND
OVERNIGHT LOWS IN THE MID 50S TO LOWER 60S. FOR PRECIPITATION...A
MODEL BLEND WAS UTILIZED DUE TO THE UNCERTAINTY OF TIMING AND
PLACEMENT OF INDIVIDUAL IMPULSES MOVING THROUGH THE MEAN UPPER LEVEL
FLOW.
ON SATURDAY...SURFACE HIGH PRESSURE TO OUR NORTH AND EAST WILL
RESULT IN A COOLER EASTERLY FLOW. 00 UTC FRI 19 JULY NAM/GFS
FORECAST SOUNDINGS FOR SATURDAY INDICATE A STABLE ATMOSPHERE OVER
CENTRAL NORTH DAKOTA WITH MID LEVEL SHORTWAVE ENERGY PRODUCING
SHOWERS. THE WEST APPEARS TO BE THE AREA TO SEE ANY LATE MORNING
OR AFTERNOON CONVECTION. THEREFORE LIMITED CONVECTION TO AREAS WEST
OF BISMARCK AND MINOT ON SATURDAY. WE ALSO CUT BACK ON THE FORECAST
HIGHS ACROSS THE NORTHEAST THIRD OF THE CWA...WITH UPPER 60S
FORECAST FOR AREAS SUCH AS BOTTINEAU AND RUGBY. THE SOUTHWEST IS
STILL FORECAST TO CLIMB INTO THE LOWER TO MIDDLE 80S.
NO SIGNIFICANT CHANGES FROM THE MODEL BLEND SOLUTION WERE MADE TO
THE REMAINDER OF THE EXTENDED FORECAST...RESULTING IN AT LEAST A
SLIGHT CHANCE OF THUNDERSTORMS EACH DAY FOR AT LEAST A PORTION OF
THE CWA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 627 AM CDT FRI JUL 19 2013
VFR CONDITIONS ARE FORECAST FOR THE 12 UTC TAF CYCLE OUTSIDE OF
THUNDERSTORMS. INCLUDED VCTS FOR KISN AND KMOT BY 22-00 UTC AND KJMS
AND KBIS BY 00-02 UTC AS A COLD FRONT MOVES SOUTH OUT OF CANADA.
LEFT THE MENTION OF THUNDER OUT FOR NOW AT KDIK DUE TO UNCERTAINTY
IN IMPACTS TO THE TERMINAL AS THE GREATER CHANCES FOR THUNDERSTORMS
LOOK TO BE NORTH AND EAST.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...AYD
LONG TERM...TWH
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
352 AM CDT FRI JUL 19 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM CDT FRI JUL 19 2013
THE HIGHLIGHT OF THE SHORT TERM IS THE CONVECTIVE POTENTIAL THIS
AFTERNOON THROUGH TONIGHT.
AS OF 0830 UTC...A COLD FRONT WAS ANALYZED FROM NORTHEAST
MANITOBA...ARCHING SOUTHWEST ACROSS NORTHERN LAKE WINNIPEG AND
INTO CENTRAL SASKATCHEWAN. THIS FRONT IS FORECAST TO CONTINUE TO
PROPAGATE SOUTH TODAY...CROSSING INTO THE NORTHERN PORTIONS OF
NORTH DAKOTA BY 20-22 UTC. THIS FEATURE WILL BE THE FOCUS FOR
CONVECTIVE DEVELOPMENT LATE THIS AFTERNOON AND THROUGH THE
NIGHT. THE 00 UTC 4 KM WRF AND 06 UTC HRRR SUGGEST SURFACE BASED
CONVECTION ENTERING NORTH DAKOTA WITHIN THE 20-22 UTC TIME FRAME
AND PROPAGATING SOUTH THROUGH THE EVENING AND OVERNIGHT WITH THE
FRONT. CANNOT RULE OUT AN ISOLATED LOW END SEVERE STORM GIVEN ML
CAPE VALUES AROUND 1000 J/KG AND DEEP LAYER SHEAR OF 40 KTS.
HOWEVER...GIVEN WEAK UPPER LEVEL FORCING...THE THREAT SEEMS
MARGINAL WITH WESTERN AND CENTRAL NORTH DAKOTA ONLY IN GENERAL
THUNDER IN THE SPC DAY 1 OUTLOOK. THERE IS SOME UNCERTAINTY AS TO
HOW LONG AFTER SUNSET CONVECTION CAN SUSTAIN ITSELF...WITH WEAK
UPPER LEVEL FORCING AND THE LACK OF A LOW LEVEL JET. THE 00 UTC
DETERMINISTIC SUITE SUGGESTS ISOLATED TO SCATTERED CONVECTION
CONTINUING IN THE VICINITY OF THE FRONT THROUGH THE NIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 352 AM CDT FRI JUL 19 2013
THE LONG TERM PERIOD WILL CONSIST OF A NORTHWEST UPPER FLOW PATTERN
WITH IMPULSES TRANSLATING THROUGH THE POLAR JET AND AFFECTING THE
LOCAL AREA ABOUT EVERY 18-24 HOURS THROUGH THE ENTIRE PERIOD. THIS
WILL RESULT IN A SEASONABLE TEMPERATURE REGIME WITH DAYTIME HIGHS
MAINLY IN THE MID 70S NORTHEAST TO THE MID 80S SOUTHWEST...AND
OVERNIGHT LOWS IN THE MID 50S TO LOWER 60S. FOR PRECIPITATION...A
MODEL BLEND WAS UTILIZED DUE TO THE UNCERTAINTY OF TIMING AND
PLACEMENT OF INDIVIDUAL IMPULSES MOVING THROUGH THE MEAN UPPER LEVEL
FLOW.
ON SATURDAY...SURFACE HIGH PRESSURE TO OUR NORTH AND EAST WILL
RESULT IN A COOLER EASTERLY FLOW. 00 UTC FRI 19 JULY NAM/GFS
FORECAST SOUNDINGS FOR SATURDAY INDICATE A STABLE ATMOSPHERE OVER
CENTRAL NORTH DAKOTA WITH MID LEVEL SHORTWAVE ENERGY PRODUCING
SHOWERS. THE WEST APPEARS TO BE THE AREA TO SEE ANY LATE MORNING
OR AFTERNOON CONVECTION. THEREFORE LIMITED CONVECTION TO AREAS WEST
OF BISMARCK AND MINOT ON SATURDAY. WE ALSO CUT BACK ON THE FORECAST
HIGHS ACROSS THE NORTHEAST THIRD OF THE CWA...WITH UPPER 60S
FORECAST FOR AREAS SUCH AS BOTTINEAU AND RUGBY. THE SOUTHWEST IS
STILL FORECAST TO CLIMB INTO THE LOWER TO MIDDLE 80S.
NO SIGNIFICANT CHANGES FROM THE MODEL BLEND SOLUTION WERE MADE TO
THE REMAINDER OF THE EXTENDED FORECAST...RESULTING IN AT LEAST A
SLIGHT CHANCE OF THUNDERSTORMS EACH DAY FOR AT LEAST A PORTION OF
THE CWA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 352 AM CDT FRI JUL 19 2013
VFR CONDITIONS ARE FORECAST FOR THE 06 UTC TAF CYCLE OUTSIDE OF
THUNDERSTORMS. INCLUDED VCTS FOR KISN AND KMOT BY 22-00
UTC...CONTINUING THEREAFTER AS ISOLATED TO SCATTERED THUNDERSTORMS
ARE POSSIBLE ALONG A COLD FRONT MOVING SOUTH FROM CANADA. KEPT
THE MENTION OF THUNDERSTORMS OUT FOR KDIK...KBIS AND KJMS FOR NOW
DUE TO UNCERTAINTY...AND WILL RE-EVALUATE WITH THE 12 UTC CYCLE.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...AYD
LONG TERM...TWH
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1246 AM CDT FRI JUL 19 2013
.UPDATE...
ISSUED AT 1246 AM CDT FRI JUL 19 2013
NO CHANGES REQUIRED WITH THIS UPDATE OTHER THAN TO BLEND TO THE 05
UTC OBSERVED TRENDS IN THE WAKE OF THE COLD FRONT PROPAGATING INTO
NORTHEAST MINNESOTA THROUGH SOUTHWEST SOUTH DAKOTA.
UPDATE ISSUED AT 942 PM CDT THU JUL 18 2013
UPDATE TO REDUCE LATE EVENING POPS AND CONFINE AREA FROM THE
TURTLE MOUNTAINS THROUGH FOSTER COUNTY. STRONG STORMS GLANCED THE
FAR NORTHEAST EARLIER THIS EVENING BUT HAVE SINCE DISSIPATED WHILE
CONVECTION CONTINUES TO THE EAST. CANNOT RULE OUT AN ISOLATED
STORM OVER THE NEXT FEW HOURS...BUT THE PROBABILITY IS LOW.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH FRIDAY)
ISSUED AT 250 PM CDT THU JUL 18 2013
THE MAIN FORECAST CONCERN FOR THE PERIOD WILL BE THUNDERSTORM
CHANCES THIS AFTERNOON AND EVENING AS WELL AS THE SEVERE POTENTIAL.
HEAT INDEX VALUES APPROACHING 100 DEGREES WILL CONTINUE ACROSS THE
SOUTHERN JAMES RIVER BASIN AHEAD OF A COLD FRONT THROUGH THE LATE
AFTERNOON. THEREFORE...WILL MAINTAIN THE CURRENT HEAT ADVISORY IN
EFFECT THROUGH 00Z.
IN ADDITION...THUNDERSTORMS ARE STILL PROGGED TO DEVELOP OVER THE
JAMES RIVER BASIN IN AN AREA OF LARGE INSTABILITY CHARACTERIZED BY
SURFACE-BASED CAPE VALUES OF 2500 J/KG. HOWEVER...MARGINAL TO LOW
DEEP LAYER SHEAR IS EXPECTED TO KEEP THIS CONVECTION BELOW SEVERE
LIMITS. THIS ACTIVITY SHOULD BE OUT OF THE JAMES RIVER BASIN BY 00Z
THIS EVENING AS THE COLD FRONT PUSHES EAST OF THE CWA.
AN UPPER WAVE OVER NORTHWESTERN NORTH DAKOTA WILL PIVOT ACROSS THE
STATE TONIGHT. ONGOING CONVECTION OVER THE SOUTHERN CANADIAN PRAIRIES
IS EXPECTED TO ENTER NORTH CENTRAL NORTH DAKOTA AFTER 23Z AS THE
WAVE PIVOTS ACROSS THE REGION. THE 3KM HRRR AND 12Z WRF KEEP THE
CONVECTION CONFINED TO AREAS NORTHEAST OF HIGHWAY 52 THROUGH 03Z.
SOME STORMS MIGHT ALREADY BE SEVERE AS THEY CROSS THE BORDER.
HOWEVER...THE SEVERE THREAT SHOULD DIMINISH AFTER 03Z WITH THE LOSS
OF DAYTIME HEATING. WILL THEREFORE INTRODUCE SEVERE WORDING IN THE
GRIDS FOR THE 23Z-03Z PERIOD FOR POINTS NORTH OF A LINE FROM MOHALL
TO DEERING TO BALTA. FURTHERMORE...WILL CONTINUE TO HIGHLIGHT THIS
THREAT IN THE HWO. AFTER 03Z...DRY CONDITIONS ARE EXPECTED AREAWIDE
AS HIGH PRESSURE BUILDS INTO THE REGION. MUCH COOLER OVERNIGHT LOWS
ARE EXPECTED WITH READINGS FROM THE MID 50S WEST TO THE LOWER 60S
SOUTHEAST.
FOR FRIDAY...HIGH PRESSURE WILL SLOWLY SINK SOUTHWARD INTO SOUTH
DAKOTA. AS IT DOES...A WEAK BAROCLINIC ZONE IS PROGGED TO SET UP
OVER NORTHERN NORTH DAKOTA. THIS FEATURE SHOULD PROVIDE FOCUS FOR
AFTERNOON CONVECTION. GIVEN THE ELEVATED NATURE OF THE THUNDERSTORM
POTENTIAL...THINK ANY CONVECTION THAT DOES DEVELOP WILL STAY BELOW
SEVERE LIMITS. TEMPERATURES WILL BE MORE SEASONAL FRIDAY WITH HIGHS
FROM THE UPPER 70S NORTH TO THE MID 80S SOUTH.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 250 PM CDT THU JUL 18 2013
THE LONG TERM PERIOD WILL BE CHARACTERIZED BY A NORTHWEST UPPER
LEVEL FLOW PATTERN WITH PERIODIC EMBEDDED SHORTWAVES MOVING THROUGH
THE FLOW. AT THIS TIME THE LONG TERM MODELS ARE DEPICTING SHORTWAVES
MOVING THROUGH THE FORECAST AREA EACH DAY...KEEPING ISOLATED TO
SCATTERED THUNDERSTORM ACTIVITY/CHANCES EACH DAY.
THE LONG TERM BEGINS FRIDAY NIGHT WITH ANOTHER SURFACE COLD FRONT
MOVING SOUTHWARD DURING THE DAYTIME FRIDAY...BECOMING STATIONARY
FRIDAY NIGHT/SATURDAY AS DRY HIGH PRESSURE MOVES INTO NORTHEASTERN
NORTH DAKOTA. EXPECT SCATTERED THUNDERSTORMS ALONG THIS BOUNDARY
FROM NORTHWEST TO SOUTH CENTRAL/SOUTHEASTERN NORTH DAKOTA. PLENTY OF
CAPE BUT LIMITED SHEAR WILL KEEP THE MENTION OF SEVERE STORMS OUT OF
THE FORECAST.
THE NEXT CHANCE OF SCATTERED THUNDERSTORMS APPEARS TO BE SUNDAY
AFTERNOON/NIGHT...THEN AGAIN MONDAY AFTERNOON/NIGHT. AT THIS TIME IT
APPEARS THAT WEDNESDAY MAY SEE A BREAK IN THE ACTION WITH DRY
SURFACE HIGH PRESSURE DEPICTED AND A LULL IN THE SHORTWAVES ACROSS
NORTH DAKOTA...BUT TIMING IS VERY IFFY WITH TIMING OF SHORTWAVES.
ANOTHER SHORTWAVE WITH A SURFACE TROUGH/FRONT TRAVERSES THE FORECAST
AREA THURSDAY.
THUS ISOLATED TO SCATTERED THUNDERSTORMS NEARLY EACH DAY. THE
COOLEST DAY SHOULD BE SATURDAY WITH HIGHS FROM THE 70S ALONG AND
NORTH AND EAST OF THE MISSOURI RIVER WITH LOW TO MID 80S SOUTH AND
WEST OF THE RIVER. OTHERWISE SEASONABLE TEMPERATURES WITH HIGHS
MAINLY IN THE 80S AND LOWS IN THE UPPER 50S TO MID 60S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1246 AM CDT FRI JUL 19 2013
VFR CONDITIONS ARE FORECAST FOR THE 06 UTC TAF CYCLE OUTSIDE OF
THUNDERSTORMS. INCLUDED VCTS FOR KISN AND KMOT BY 22-00
UTC...CONTINUING THEREAFTER AS ISOLATED TO SCATTERED THUNDERSTORMS
ARE POSSIBLE ALONG A COLD FRONT MOVING SOUTH FROM CANADA FRIDAY
EVENING. KEPT THE MENTION OF THUNDERSTORMS OUT FOR KDIK...KBIS AND
KJMS DUE TO UNCERTAINTY...AND WILL RE-EVALUATE WITH THE 12 UTC
CYCLE.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...TM
LONG TERM...JV
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1137 PM CDT THU JUL 18 2013
.UPDATE...
ISSUED AT 1130 PM CDT THU JUL 18 2013
WIDELY SCATTERED/ISOLATED CONVECTION CONTINUES ACROSS NORTHERN MN
ASSOCIATED WITH SHORT WAVE TRACKING ALONG INTERNATIONAL BORDER.
MAINTAINED SOME CHC POPS ACROSS NE THIRD OF FORECAST AREA FOR A
FEW MORE HOURS BEFORE ANY CONVECTION SHOULD BE SHIFTING EAST OF
FA. CELL ACROSS N BELTRAMI HAS STRENGTHENED SLIGHTLY HOWEVER STILL
BELOW SEVERE LIMITS AND WILL ALLOW WATCH TO EXPIRE AT MIDNIGHT.
TRIMMED POPS FARTHER WEST BEHIND BOUNDARIES FOR REMAINDER OF THE
NIGHT. REMAINDER OF THE FORECAST BASICALLY UNCHANGED AS
TEMPERATURES AND CLOUD TRENDS ON TRACK.
UPDATE ISSUED AT 945 PM CDT THU JUL 18 2013
CONVECTION STRUGGLED ALL EVENING TO GET GOING ACROSS EASTERN FA
ALONG PREFRONTAL TROUGH/WARM FRONT. ABOVE BOUNDARY CLOSE TO EXITING FA
TO THE EAST AND NOW CONFINED TO HUBBARD/BELTRAMI COUNTY. TRIMMED
BACK ON POPS THIS AREA. FARTHER NORTHWEST MORE ROBUST BUT WIDELY
SCATTERED CONVECTION CONTINUES ALONG INTERNATIONAL BORDER AREA
ASSOCIATED WITH SECONDARY BOUNDARY AND MID LEVEL WAVE RIDING ALONG
INTERNATIONAL BORDER. HAVE HIGHEST POPS ALONG INTERNATIONAL BORDER
INTO EARLY AM AS FEATURE CONTINUES TO PROPAGATE EAST IN
MODERATELY UNSTABLE AIR MASS. ELSEWHERE ADJUSTED POPS ACCORDINGLY
BASED ON CURRENT RADAR TRENDS. REMAINDER OF FORECAST UNCHANGED FOR
THIS UPDATE.
UPDATE ISSUED AT 645 PM CDT THU JUL 18 2013
DEEP CONVECTION BECOMING A LITTLE BETTER ORGANIZED ALONG FRONTAL
BOUNDARY FROM NEAR FSE NE TO INL. SO FAR CELLS HAVE REMAINED BLO
SVR LIMITS HOWEVER WILL CONTINUE TO MONITOR. FARTHER NW ISOLD
SHRA/TSRA CLOSING IN ON FAR NW FA HOWEVER STRONGER STORMS STILL
WELL NORTH OF INL BORDER AND CONFIDENCE NOT VERY HIGH ON SEVERE
POTENTIAL THIS AREA. FOR NOW WITH STRENGTH OF MID LEVEL IMPULSE
AND DEGREE OF INSTABILITY CANNOT RULE OUT ISLD STRONG STORM SO
WILL MAINTAIN STRONGER STORM WORDING THIS AREA. MADE SOME MINOR
POP ADJUSTMENTS THROUGH MID EVENING TRYING TO FINE TUNE AREAS FOR
BEST STORM POTENTIAL ACROSS N CENTRAL MN. PULLED POPS ACROSS
CENTRAL FA IN BETWEEN BOUNDARIES WHERE CONVECTION NOT ANTICIPATED.
TEMPERATURES STILL WARM/HUMID BUT BLO HEAT ADVISORY CRITERIA SO WILL
ALLOW TO EXPIRE ON TIME. ANY OTHER CHANGES MINIMAL THIS UPDATE.
&&
.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 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1132 PM CDT THU JUL 18 2013
ISOLATED TSRA WILL CONTINUE ALONG AND NORTH OF A LINE FROM TVF TO BJI
FOR A FEW MORE HOURS HOWEVER CIGS/VSBY TO REMAIN VFR. REMAINDER OF
FA WILL REMAIN VFR THROUGH THE FORECAST PERIOD. CONFIDENCE NOT
HIGH ENOUGH TO ADD PCPN MENTION TOMORROW AFTERNOON AHEAD OF NEXT
COLD FRONT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...TG
LONG TERM...TG/SPEICHER
AVIATION...VOELKER
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
143 PM EDT FRI JUL 19 2013
.SYNOPSIS...
HOT AND HUMID AIR MASS OVER THE REGION WILL BREAK DOWN TONIGHT AS A
COLD FRONT MOVES INTO THE REGION. STORMS WILL ACCOMPANY THE FRONT
AS IT MOVES THROUGH THE AREA ON SATURDAY. COOLER AND DRIER WEATHER
ON TAP FOR SUNDAY...BUT THE HUMIDITY WILL RETURN EARLY NEXT WEEK.
TEMPERATURES WILL BE MORE COMFORTABLE WITH HIGHS AT OR SLIGHTLY
BELOW NORMAL THROUGH MOST OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATE...MADE MINOR ADJUSTMENTS FOR THE NEXT SEVERAL DAYS. FOR
TODAY ADDED A SLIGHT CHANCE TO THE NORTHWEST COUNTIES WHERE LIKE
THE PAST FEW DAYS THE HRRR SHOWED AFTERNOON DEVELOPMENT.
TEMPERATURES OVERNIGHT REMAINED HIGH IN THE MID 70S...WHICH WILL
PROVIDE A WARM START FOR HEAT ADVISORY CONDITIONS LATER TODAY.
LOOK FOR SCATTERED CLOUDS DEVELOPING THIS AFTERNOON...BUT NOT
ENOUGH COVERAGE TO KEEP TEMPERATURES FROM RETURNING TO THE
LOWER 90S...AND IN SOME W SITES IN THE MID 90S. EXPECT SOME LOW
LEVEL WIND SHEAR TO STRENGTHEN TODAY WITH STRONGER SOUTHWEST WINDS
ALOFT. MIXING MAY CAUSE A DROP OF DEWPOINTS SLIGHTLY...BUT THE
MOISTURE BEING ADVECTED IN COULD COUNTER THIS AND EASILY SUPPORT
HEAT INDEX VALUES AROUND 100-104F THIS AFTERNOON. SOME WEAK
CONVERGENCE COULD BE ENOUGH TO TRIGGER SOME ISOLATED STORMS MAINLY
ACROSS OUR SOUTHERN TIER OF COUNTIES UP INTO NW PA. THE LAKESHORE
COUNTIES SHOULD REMAIN RAIN FREE FOR THE BETTER PART OF THE DAY.
THE CONVECTION IS EXPECTED TO GET GOING MID DAY NORTH IN MI AND CANADA
WHERE THE DYNAMICS WILL BE THE BEST. MODELS ARE INDICATING SOME
SUBSIDENCE OVER MOST OF OUR AREA THIS AFTERNOON WHICH COULD LEAVE
US WITH MOSTLY SUNNY SKIES EXCEPT THE MORE SOUTHERN COUNTIES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
ALL EYES WILL BE ON THE CONVECTION ANTICIPATED TO OUR NORTH AND
ANY OUTFLOWS THAT COULD SINK ACROSS THE LAKE AND TRIGGER STORMS
THIS EVENING IN OUR NORTHERN COUNTIES. EXCLUDING THAT
SCENARIO...THE BEST CHANCE FOR THUNDERSTORMS WON`T BE UNTIL 03-06Z
AS THE FRONT SINKS SOUTH INTO OUR AREA. THE BOTTLED UP ENERGY IN
PLACE OVER THE REGION WITH CAPES EXCEEDING 3K J/KG WILL BE REDUCED
MARGINALLY OVERNIGHT...BUT NOT ENOUGH TO RULE OUT STRONG TO SEVERE
STORMS. WITH UNIDIRECTIONAL WIND SHEAR...WITH A DECENT AMOUNT OF
SPEED SHEAR...THE HIGHEST THREAT WILL BE STRONG STRAIGHT LINE
WINDS. THE SLOW MOVING FRONT WILL PUSH INTO THE AREA DURING THE
EARLY MORNING HOURS ON SATURDAY. THIS WILL PROVIDE A FOCUS FOR
MORE CONVECTION ON SATURDAY...GRADUALLY CLEARING FROM NW TO SE
DURING THE AFTERNOON. SPC HAS THE REGION OUTLOOKED FOR SLIGHT RISK
OF SEVERE WEATHER FOR SATURDAY. THE STORM MOTIONS WILL BE
SUFFICIENT TO KEEP THE FLOOD RISK LIMITED TO ONLY AREAS WHERE
THERE MAY BE TRAINING. CONCERN HERE WILL BE WHERE THE FRONT OR
OTHER BOUNDARIES HANG UP...OTHERWISE THE HIGHEST QPF LOOKS TO BE
OVER NW PA. OVERALL LOOKING AT A 0.5" WIDESPREAD AVERAGE WITH
LOCALLY HIGHER AMOUNTS.
BEHIND FROPA A COOLER AND DRIER HIGH OUT OF CANADA WILL SLIDE IN
FOR SUNDAY GIVING A NICE BREAK TO THE HOT HUMID WEATHER OF THE
LAST WEEK. BY MONDAY AN UPPER LVL TROF WILL DEVELOP OVER THE OH
VALLEY AND WE`LL SEE A RETURN OF MUGGY CONDITIONS. TEMPERATURES
HOWEVER WILL REMAIN AT OR BELOW SEASONAL NORMALS AS THE
THICKNESSES DROP. THE PRESENCE OF THE TROUGH AND INCREASED
MOISTURE RETURN WILL UNFORTUNATELY PUT US BACK INTO A WETTER
PATTERN...THOUGH NOTHING ORGANIZED AT THIS TIME.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
STILL PLENTY OF UNCERTAINTY IN THE FORECAST FOR TUESDAY THROUGH
THURSDAY AS PIECES OF JET ENERGY MOVE THROUGH A TROUGH THAT WILL BE
OVER THE GREAT LAKES REGION. FOR NOW HAVE SLIGHT CHANCE TO CHANCE
POPS IN THE FORECAST FOR MOST OF THE REGION.
TEMPERATURES TUESDAY THROUGH THURSDAY SHOULD BE VERY CLOSE TO
SEASONAL AVERAGES.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
POP UP THUNDERSTORMS WILL SPREAD ACROSS MUCH OF NE OH/NW PA THIS
AFTERNOON...INLAND FROM THE LAKE ERIE LAKE BREEZE. THE ODDS OF A
DIRECT HIT ON AN AVIATION TERMINAL ARE PROBABLY 30-40 PERCENT AND
WILL FORECAST "VICINITY" IN THE TAF THIS AFTERNOON EXCEPT AT KTOL
AND KERI WHERE THEY SHOULD BE PROTECTED BY THE PROXIMITY TO LAKE
ERIE.
A LINE OF SHOWERS AND THUNDERSTORMS WILL SLIDE ACROSS LAKE
ERIE TONIGHT AHEAD OF THE COLD FRONT. THE STORMS MAY BE WEAKENING
BY THE EARLY MORNING HOURS BUT THERE IS A GOOD CHANCE OF MVFR
CONDITIONS AND A CHANCE FOR IFR VISIBILITIES IN THE HEAVIER
THUNDERSTORMS.
MVFR STRATOCUMULUS CEILINGS WILL LIKELY DEVELOP AFTER THE
SHOWERS/STORMS EARLY SATURDAY OR FIRST THING SATURDAY MORNING.
CEILINGS WILL LIFT TO VFR SATURDAY AFTERNOON. NEW SHOWERS/STORMS
MAY DEVELOP SATURDAY AFTERNOON FROM NEAR KYNG TO KCAK AND KMFD BUT
NOT A LOT OF CONFIDENCE AND WILL LEAVE THEM OUT OF THE FORECAST
FOR NOW.
GUSTY WINDS THIS AFTERNOON WILL SETTLE TONIGHT AND SHIFT
TO THE WEST SATURDAY MORNING AS THE COLD FRONT BEGINS TO SLIDE
ACROSS THE AREA.
.OUTLOOK...NON VFR IN PATCHY EARLY MORNING FOG. SHOWERS AND
THUNDERSTORMS MAY ALSO CAUSE NON VFR CONDITIONS MONDAY THRU
WEDNESDAY.
&&
.MARINE...
A COLD FRONT WILL MOVE INTO THE UPPER GREAT LAKES TODAY AS HIGH
PRESSURE MOVES TO THE SOUTHEASTERN US. THIS WILL ALLOW A STRONGER
PRESSURE GRADIENT TO DEVELOP OVER THE LAKE TODAY. SOUTHWEST WINDS OF
10 TO 20 KNOTS SHOULD BE ENOUGH TO BUILD WAVES TO 3 TO 5 FEET FROM
WILLOWICK TO RIPLEY. THE LARGEST WAVES WILL LIKELY BE IN THE PA
WATERS. SO WITH THAT SAID WE WILL HOIST A SMALL CRAFT ADVISORY THAT
WILL REMAIN IN EFFECT THROUGH TONIGHT.
THE COLD FRONT WILL MOVE SOUTHEAST ACROSS LAKE ERIE ON SATURDAY.
HIGH PRESSURE WILL THEN BUILD ACROSS THE GREAT LAKES ON SUNDAY
BEFORE SHIFTING EAST AND STAYING NORTH OF LAKE ERIE ON MONDAY.
NORTHEAST WINDS WILL DEVELOP BY SUNDAY MORNING WITH CHOPPY
CONDITIONS POSSIBLE FOR THE WESTERN HALF OF THE LAKE. WINDS SHOULD
BECOME SOUTHERLY BY MONDAY AS WARM FRONT LIFTS ACROSS THE LAKE.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR OHZ003-006>011-
013-017>023-027>033-036>038-047.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR LEZ147>149.
&&
$$
SYNOPSIS...JAMISON
NEAR TERM...JAMISON/TK
SHORT TERM...JAMISON
LONG TERM...MULLEN
AVIATION...KOSARIK
MARINE...MULLEN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1002 AM EDT FRI JUL 19 2013
.SYNOPSIS...
HOT AND HUMID AIRMASS OVER THE REGION WILL BREAK DOWN TONIGHT AS A
COLD FRONT MOVES INTO THE REGION. STORMS WILL ACCOMPANY THE FRONT
AS IT MOVES THROUGH THE AREA ON SATURDAY. COOLER AND DRIER WEATHER
ON TAP FOR SUNDAY...BUT THE HUMIDITY WILL RETURN EARLY NEXT WEEK.
TEMPERATURES WILL BE MORE COMFORTABLE WITH HIGHS AT OR SLIGHTLY
BELOW NORMAL THROUGH MOST OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATE...MADE MINOR ADJUSTMENTS FOR THE NEXT SEVERAL DAYS. FOR
TODAY ADDED A SLIGHT CHANCE TO THE NORTHWEST COUNTIES WHERE LIKE
THE PAST FEW DAYS THE HRRR SHOWED AFTERNOON DEVELOPMENT.
TEMPERATURES OVERNIGHT REMAINED HIGH IN THE MID 70S...WHICH WILL
PROVIDE A WARM START FOR HEAT ADVISORY CONDITIONS LATER TODAY.
LOOK FOR SCATTERED CLOUDS DEVELOPING THIS AFTERNOON...BUT NOT
ENOUGH COVERAGE TO KEEP TEMPERATURES FROM RETURNING TO THE
LOWER 90S...AND IN SOME W SITES IN THE MID 90S. EXPECT SOME LOW
LEVEL WIND SHEAR TO STRENGTHEN TODAY WITH STRONGER SOUTHWEST WINDS
ALOFT. MIXING MAY CAUSE A DROP OF DEWPOINTS SLIGHTLY...BUT THE
MOISTURE BEING ADVECTED IN COULD COUNTER THIS AND EASILY SUPPORT
HEAT INDEX VALUES AROUND 100-104F THIS AFTERNOON. SOME WEAK
CONVERGENCE COULD BE ENOUGH TO TRIGGER SOME ISOLATED STORMS MAINLY
ACROSS OUR SOUTHERN TIER OF COUNTIES UP INTO NW PA. THE LAKESHORE
COUNTIES SHOULD REMAIN RAIN FREE FOR THE BETTER PART OF THE DAY.
THE CONVECTION IS EXPECTED TO GET GOING MID DAY NORTH IN MI AND CANADA
WHERE THE DYNAMICS WILL BE THE BEST. MODELS ARE INDICATING SOME
SUBSIDENCE OVER MOST OF OUR AREA THIS AFTERNOON WHICH COULD LEAVE
US WITH MOSTLY SUNNY SKIES EXCEPT THE MORE SOUTHERN COUNTIES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
ALL EYES WILL BE ON THE CONVECTION ANTICIPATED TO OUR NORTH AND
ANY OUTFLOWS THAT COULD SINK ACROSS THE LAKE AND TRIGGER STORMS
THIS EVENING IN OUR NORTHERN COUNTIES. EXCLUDING THAT
SCENARIO...THE BEST CHANCE FOR THUNDERSTORMS WON`T BE UNTIL 03-06Z
AS THE FRONT SINKS SOUTH INTO OUR AREA. THE BOTTLED UP ENERGY IN
PLACE OVER THE REGION WITH CAPES EXCEEDING 3K J/KG WILL BE REDUCED
MARGINALLY OVERNIGHT...BUT NOT ENOUGH TO RULE OUT STRONG TO SEVERE
STORMS. WITH UNIDIRECTIONAL WIND SHEAR...WITH A DECENT AMOUNT OF
SPEED SHEAR...THE HIGHEST THREAT WILL BE STRONG STRAIGHT LINE
WINDS. THE SLOW MOVING FRONT WILL PUSH INTO THE AREA DURING THE
EARLY MORNING HOURS ON SATURDAY. THIS WILL PROVIDE A FOCUS FOR
MORE CONVECTION ON SATURDAY...GRADUALLY CLEARING FROM NW TO SE
DURING THE AFTERNOON. SPC HAS THE REGION OUTLOOKED FOR SLIGHT RISK
OF SEVERE WEATHER FOR SATURDAY. THE STORM MOTIONS WILL BE
SUFFICIENT TO KEEP THE FLOOD RISK LIMITED TO ONLY AREAS WHERE
THERE MAY BE TRAINING. CONCERN HERE WILL BE WHERE THE FRONT OR
OTHER BOUNDARIES HANG UP...OTHERWISE THE HIGHEST QPF LOOKS TO BE
OVER NW PA. OVERALL LOOKING AT A 0.5" WIDESPREAD AVERAGE WITH
LOCALLY HIGHER AMOUNTS.
BEHIND FROPA A COOLER AND DRIER HIGH OUT OF CANADA WILL SLIDE IN
FOR SUNDAY GIVING A NICE BREAK TO THE HOT HUMID WEATHER OF THE
LAST WEEK. BY MONDAY AN UPPER LVL TROF WILL DEVELOP OVER THE OH
VALLEY AND WE`LL SEE A RETURN OF MUGGY CONDITIONS. TEMPERATURES
HOWEVER WILL REMAIN AT OR BELOW SEASONAL NORMALS AS THE
THICKNESSES DROP. THE PRESENCE OF THE TROUGH AND INCREASED
MOISTURE RETURN WILL UNFORTUNATELY PUT US BACK INTO A WETTER
PATTERN...THOUGH NOTHING ORGANIZED AT THIS TIME.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
STILL PLENTY OF UNCERTAINTY IN THE FORECAST FOR TUESDAY THROUGH
THURSDAY AS PIECES OF JET ENERGY MOVE THROUGH A TROUGH THAT WILL BE
OVER THE GREAT LAKES REGION. FOR NOW HAVE SLIGHT CHANCE TO CHANCE
POPS IN THE FORECAST FOR MOST OF THE REGION.
TEMPERATURES TUESDAY THROUGH THURSDAY SHOULD BE VERY CLOSE TO
SEASONAL AVERAGES.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
PATCHY MORNING MVFR FOG HAS OCCURRED ONCE AGAIN FOR INLAND TAF
SITES BUT WILL QUICKLY BURN OFF. OTHERWISE THERE WILL BE VFR
CONDITIONS WITH AFTERNOON CUMULUS. SOUTHWESTERLY WINDS WILL BE
STRONGER TODAY WITH GUSTS AROUND 20 KNOTS LIKELY. THE STRONGEST
WINDS WILL LIKELY BE ACROSS NW OHIO INCLUDING KTOL AND KFDY WITH
GUSTS AROUND 25 KNOTS. CANT COMPLETELY RULE OUT SOME ISOLATED
CONVECTION OVER THE SOUTHERN TIER OF NY THAT MAY BUILD BACK INTO
PORTIONS OF NW PA AND SOUTH OF A LINE FROM KFDY TO KYNG.
WE WILL THEN AWAIT THE ARRIVAL OF THUNDERSTORMS AFTER SUNSET. MOST
OF THEM WILL LIKELY BE AFTER 03Z AND GRADUALLY SAG SOUTH AND EAST
WITH A COLD FRONT. SOME OF THESE STORMS WILL BE CAPABLE OF STRONG
WINDS.
.OUTLOOK...NON VFR IN PATCHY EARLY MORNING FOG. SHOWERS AND
THUNDERSTORMS MAY ALSO CAUSE NON VFR CONDITIONS SATURDAY AND
TUESDAY.
&&
.MARINE...
A COLD FRONT WILL MOVE INTO THE UPPER GREAT LAKES TODAY AS HIGH
PRESSURE MOVES TO THE SOUTHEASTERN US. THIS WILL ALLOW A STRONGER
PRESSURE GRADIENT TO DEVELOP OVER THE LAKE TODAY. SOUTHWEST WINDS OF
10 TO 20 KNOTS SHOULD BE ENOUGH TO BUILD WAVES TO 3 TO 5 FEET FROM
WILLOWICK TO RIPLEY. THE LARGEST WAVES WILL LIKELY BE IN THE PA
WATERS. SO WITH THAT SAID WE WILL HOIST A SMALL CRAFT ADVISORY THAT
WILL REMAIN IN EFFECT THROUGH TONIGHT.
THE COLD FRONT WILL MOVE SOUTHEAST ACROSS LAKE ERIE ON SATURDAY.
HIGH PRESSURE WILL THEN BUILD ACROSS THE GREAT LAKES ON SUNDAY
BEFORE SHIFTING EAST AND STAYING NORTH OF LAKE ERIE ON MONDAY.
NORTHEAST WINDS WILL DEVELOP BY SUNDAY MORNING WITH CHOPPY
CONDITIONS POSSIBLE FOR THE WESTERN HALF OF THE LAKE. WINDS SHOULD
BECOME SOUTHERLY BY MONDAY AS WARM FRONT LIFTS ACROSS THE LAKE.
&&
.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...SMALL CRAFT ADVISORY UNTIL 4 AM EDT SATURDAY FOR LEZ147>149.
&&
$$
SYNOPSIS...JAMISON
NEAR TERM...JAMISON/TK
SHORT TERM...JAMISON
LONG TERM...MULLEN
AVIATION...MULLEN
MARINE...MULLEN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
152 PM EDT FRI JUL 19 2013
.SYNOPSIS...
THE SUBTROPICAL RIDGE OVER THE EASTERN UNITED STATES WILL WEAKEN
AND SHIFT EASTWARD...YIELDING TO A VIGOROUS NORTHERN STREAM
SHORTWAVE TROUGH MOVING THROUGH THE GREAT LAKES INTO THE NEW
ENGLAND. IT WILL BE UNSEASONABLY WARM UNTIL THE ASSOCIATED COLD
FRONTAL PASSAGE LATER SATURDAY. THE COLD FRONT COULD TRIGGER SOME
SEVERE THUNDERSTORMS. A BROAD UPPER LEVEL TROUGH SHOULD BUILD
OVER THE REGION FROM SUNDAY INTO NEXT WEEK. THIS PATTERN WILL
FEATURE A RETURN TO NEAR NORMAL TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
17Z...TSTMS ARE DEVELOPING IN AREAS WHERE THE MESO MDLS HAD
PROJECTED - ON THE ELEVATED TERRAIN FROM NRN WV INTO SW PA AND
DOWNWIND OF LAKE ERIE. A FEW ISOLD CELLS ALSO FIRED OVER THE SE
PIEDMONT FROM NEAR MDT-LNS TO JUST NORTH OF RDG. STORM NEAR LNS
GREW QUICKLY TAPPING ABUNDANT CAPE (90/75 AT 16Z) WITH TOPS OVER
40KFT. THE LATEST RAPID-REFRESH HRRR SUGGEST A LINE OF STORMS MAY
DOWNWIND OF LAKE ERIE FROM NRN OH ACRS NW PA LATE THIS AFTN. AGAIN
MADE VERY MINOR CHANGES TO THE GOING FCST OF ISOLD TO SCT TSTMS.
17-18Z HX VALUES MAY PUSH 105F AT LNS AND MDT BUT WILL CONTINUE
WITH HEAT ADVY.
PREVIOUS DISCUSSION...
14-15Z...VISIBLE SATL LOOPS SHOW CU FIELD GOING UP ALONG ON THE
WRN AND CNTRL RIDGES...PARALLEL TO THE LLVL FLOW INDICATING BLYR
DESTABILIZATION. 14Z RUC ML CAPES ARE RUNNING BTWN 2-2.5K J/KG PER
SPC MESO PAGE. LATEST OBS STILL SHOW SOME 6-7SM HZ WITH SFC
DEWPOINTS IN THE LOW 70S. TEMPS SHOULD REACH THE LOW 90S IN THE
LWR SUSQ VLY BY 15Z WITH HEAT INDEXES APPROACHING 100F.
THE MAIN FCST CHALLENGE FOR TODAY CONTINUES TO BE FOCUSED ON THE
DEVELOPMENT/PLACEMENT OF DIURNAL CONVECTION. WITH AFTN TEMPS IN
THE UPPER 80S TO MID 90S AND SFC DEWPTS BTWN 65-70F...CAPES WILL
BE ROBUST AND EASILY SUPPORT UPDRAFTS. QUESTION REMAINS AS TO THE
EVOLUTION OF STORMS GIVEN NEBULOUS FORCING AND WARM 700MB TEMPS.
RAPID-REFRESH MESO MDL DATA IS STILL SHOWING THE GREATEST CVRG OF
TSTMS IN WRN/SWRN PA INTO WV. THIS MAY BE DUE TO A WK SHORTWAVE
ROTATING FROM KY INTO THE UPPER OH VLY ON THE NW PERIPHERY OF
RETREATING UPPER RIDGE. THE TERRAIN WILL ALSO ACT TO ENHANCE
LIFT. SOME CONVECTION IS ALSO PSBL NEAR THE LAKESHORE BOUNDARY
OVER THE NW MTNS. OVERALL...EXPECT ISOLD TO WDLY SCT TSTMS AS WE
GET LATER IN THE DAY. THE ENVIRONMENT SHOULD FAVOR MAINLY NON-SVR
MULTI-CELL STORMS GIVEN HIGH CAPE AND RELATIVELY WEAK 0-6KM SHEAR.
A HEAT ADVISORY REMAINS IN EFFECT FOR THE S-CENTRAL MTNS AND SUSQ
VLY UNTL 8PM. HEAT INDEXES/APPARENT TEMPERATURES ARE FCST TO REACH
THE 100 TO 104F RANGE...RESULTING IN AN ELEVATED RISK OF HEAT-
RELATED ILLNESS ESPECIALLY THOSE WITHOUT AC OR OUTDOORS FOR AN
EXTENDED PERIOD.
AFTN/EVE STORMS SHOULD WEAKEN INTO TONIGHT WITH THE LOSS OF
HEATING. IT WILL BE A WARM HUMID/MUGGY OVERNIGHT WITH INCREASED
SOUTHERLY FLOW AHEAD OF THE APPROACHING FRONTAL SYSTEM - WHICH
SHOULD REACH THE ST. LAWRENCE VLY AND LWR LKS REGIONS BY DAYBREAK
SATURDAY.
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
BROAD CYCLONIC FLOW ALOFT ASSOCIATED WITH AN UPPER LEVEL TROUGH
WILL SPREAD SEWD FROM THE GREAT LAKES REGION ACRS THE OH VLY INTO
THE NRN APPLCHNS. A 60-75KT MID-LVL JET WILL MOVE THROUGH THE SE-
SIDE OF THE TROUGH ACRS QUEBEC. A COLD FRONT...CURRENTLY CROSSING
CENTRAL WI AND N-CENTRL LWR MI...SHOULD BE ACTIVE AT THE START OF
THE PERIOD WITH SHOWERS AND STORMS INVOF THE ST.LAWRENCE VLY SWWD
INTO THE LWR/ERN LAKES. AS THE COLD FRONT CONTINUES TO PUSH SEWD
INTO PA BY SAT AFTN...EXPECT CONVECTION TO EXPAND IN COVERAGE AND
INTENSITY WHICH WILL COINCIDE WITH SFC HEATING IN THE WARM SECTOR.
THE PRE-FRONTAL ENVIRONMENT WILL BE CHARACTERIZED BY MODERATE
INSTABILITY AND 30+ KTS OF 0-6KM SHEAR...WHICH SHOULD SUPPORT
ORGANIZED STORM STRUCTURES. THE UNIDIRECTIONAL WIND PROFILES
SUGGEST THE PRIMARY SEVERE STORM THREAT WILL BE DMGG WINDS WITH
SOME LARGE HAIL ALSO POSSIBLE WHERE STORMS CAN INGEST THE HIGH
CAPES. SPC HAS MAINTAINED A SLGT RISK OUTLOOK FOR SEVERAL DAYS
NOW AND EXPECT THIS TO PAN-OUT DURING THE DAY TOMORROW. THE WILD
CARD MAY BE THE DEVELOPMENT OF AN MCS WHICH COULD COMPLICATE
THINGS PRIOR TO FROPA.
SREF/GEFS PWAT FCSTS SUGGEST THE COLD FRONT WILL CLEAR THE NRN
ZONES BY 00Z BUT LINGER OVER SRN PA INTO SUNDAY MORNING. THEREFORE
KEPT LOW POPS ACRS THE SRN 1/2 TO 1/3 OF THE CWA LATE TONIGHT. AS
DRIER AIR ARRIVES BEHIND THE FRONT...LOOK FOR A COOLER...MORE
COMFORTABLE OVERNIGHT PERIOD OVER THE N-CNTRL MTNS.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
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 TO SHOWERS SHOULD BE LOW PERHAPS BEST
CHANCE IN 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.
THUS AS ANOTHER WAVE APPROACHES FROM THE WEST IT WILL LIKELY PULL
SOME OF THE MOISTURE BACK INTO THE REGION LATE MONDAY INTO TUESDAY
INCREASING THE CHANCE OF SHOWERS AND THUNDERSTORMS.
THE 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 /18Z FRIDAY THROUGH WEDNESDAY/...
VFR CUMULUS WILL CONTINUE TO BUILD THRU THE AFTN WITH VISBYS IN
THE 6-8SM RANGE IN HZ DUE TO VERY MOIST BLYR /DEWPOINTS IN THE
UPPER 60S TO LOW 70S/. INCREASING INSTABILITY SHOULD COMBINE WITH
THE TERRAIN TO PROMOTE ISOLD TO SCT TSTM ACTIVITY WITH INITIATION
IN THE 17-20Z TIMEFRAME. WILL CONTINUE TO SHOW VCTS AND CB/S IN
THE TAFS GIVEN UNCERTAINTY IN EXACT LOCATION OF STORMS.
W/SW LLVL FLOW AHEAD OF APPROACHING COLD FRONT SHOULD LIMIT FOG/ST
FORMATION LATE TONIGHT...ESPECIALLY OVER THE WRN AREAS. ERN TAFS
HAVE A BETTER SHOT A GOING CLR/CALM SO COULD SEE SOME LCL
RESTRICTIONS BY DAYBREAK SATURDAY. THE COLD FRONT WILL CROSS THE
REGION LATER SATURDAY AND TRIGGER SCT STG TO SVR STORMS. THE WND
SHIFT SHOULD OCCUR FROM NW-SE BY SAT NIGHT.
OUTLOOK...
SAT...VFR. PM TSTM IMPACTS. SOME STORMS MAY BE SVR.
SUN...MVFR TO VFR. SHOWERS/ISOLD TSRA PSBL SOUTH.
MON...VFR.
TUES...VFR WITH PM SHOWERS/THUNDERSTORMS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ019-026>028-
035>037-041-042-045-046-049>053-056>059-063>066.
&&
$$
SYNOPSIS...GRUMM/STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...GRUMM/MARTIN
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1259 PM EDT FRI JUL 19 2013
.SYNOPSIS...
THE SUBTROPICAL RIDGE OVER THE EASTERN UNITED STATES WILL WEAKEN
AND SHIFT EASTWARD...YIELDING TO A VIGOROUS NORTHERN STREAM
SHORTWAVE TROUGH MOVING THROUGH THE GREAT LAKES INTO THE NEW
ENGLAND. IT WILL BE UNSEASONABLY WARM UNTIL THE ASSOCIATED COLD
FRONTAL PASSAGE LATER SATURDAY. THE COLD FRONT COULD TRIGGER SOME
SEVERE THUNDERSTORMS. A BROAD UPPER LEVEL TROUGH SHOULD BUILD
OVER THE REGION FROM SUNDAY INTO NEXT WEEK. THIS PATTERN WILL
FEATURE A RETURN TO NEAR NORMAL TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
17Z...TSTMS ARE DEVELOPING IN AREAS WHERE THE MESO MDLS HAD
PROJECTED - ON THE ELEVATED TERRAIN FROM NRN WV INTO SW PA AND
DOWNWIND OF LAKE ERIE. A FEW ISOLD CELLS ALSO FIRED OVER THE SE
PIEDMONT FROM NEAR MDT-LNS TO JUST NORTH OF RDG. STORM NEAR LNS
GREW QUICKLY TAPPING ABUNDANT CAPE (90/75 AT 16Z) WITH TOPS OVER
40KFT. THE LATEST RAPID-REFRESH HRRR SUGGEST A LINE OF STORMS MAY
DOWNWIND OF LAKE ERIE FROM NRN OH ACRS NW PA LATE THIS AFTN. AGAIN
MADE VERY MINOR CHANGES TO THE GOING FCST OF ISOLD TO SCT TSTMS.
17-18Z HX VALUES MAY PUSH 105F AT LNS AND MDT BUT WILL CONTINUE
WITH HEAT ADVY.
PREVIOUS DISCUSSION...
14-15Z...VISIBLE SATL LOOPS SHOW CU FIELD GOING UP ALONG ON THE
WRN AND CNTRL RIDGES...PARALLEL TO THE LLVL FLOW INDICATING BLYR
DESTABILIZATION. 14Z RUC ML CAPES ARE RUNNING BTWN 2-2.5K J/KG PER
SPC MESO PAGE. LATEST OBS STILL SHOW SOME 6-7SM HZ WITH SFC
DEWPOINTS IN THE LOW 70S. TEMPS SHOULD REACH THE LOW 90S IN THE
LWR SUSQ VLY BY 15Z WITH HEAT INDEXES APPROACHING 100F.
THE MAIN FCST CHALLENGE FOR TODAY CONTINUES TO BE FOCUSED ON THE
DEVELOPMENT/PLACEMENT OF DIURNAL CONVECTION. WITH AFTN TEMPS IN
THE UPPER 80S TO MID 90S AND SFC DEWPTS BTWN 65-70F...CAPES WILL
BE ROBUST AND EASILY SUPPORT UPDRAFTS. QUESTION REMAINS AS TO THE
EVOLUTION OF STORMS GIVEN NEBULOUS FORCING AND WARM 700MB TEMPS.
RAPID-REFRESH MESO MDL DATA IS STILL SHOWING THE GREATEST CVRG OF
TSTMS IN WRN/SWRN PA INTO WV. THIS MAY BE DUE TO A WK SHORTWAVE
ROTATING FROM KY INTO THE UPPER OH VLY ON THE NW PERIPHERY OF
RETREATING UPPER RIDGE. THE TERRAIN WILL ALSO ACT TO ENHANCE
LIFT. SOME CONVECTION IS ALSO PSBL NEAR THE LAKESHORE BOUNDARY
OVER THE NW MTNS. OVERALL...EXPECT ISOLD TO WDLY SCT TSTMS AS WE
GET LATER IN THE DAY. THE ENVIRONMENT SHOULD FAVOR MAINLY NON-SVR
MULTI-CELL STORMS GIVEN HIGH CAPE AND RELATIVELY WEAK 0-6KM SHEAR.
A HEAT ADVISORY REMAINS IN EFFECT FOR THE S-CENTRAL MTNS AND SUSQ
VLY UNTL 8PM. HEAT INDEXES/APPARENT TEMPERATURES ARE FCST TO REACH
THE 100 TO 104F RANGE...RESULTING IN AN ELEVATED RISK OF HEAT-
RELATED ILLNESS ESPECIALLY THOSE WITHOUT AC OR OUTDOORS FOR AN
EXTENDED PERIOD.
AFTN/EVE STORMS SHOULD WEAKEN INTO TONIGHT WITH THE LOSS OF
HEATING. IT WILL BE A WARM HUMID/MUGGY OVERNIGHT WITH INCREASED
SOUTHERLY FLOW AHEAD OF THE APPROACHING FRONTAL SYSTEM - WHICH
SHOULD REACH THE ST. LAWRENCE VLY AND LWR LKS REGIONS BY DAYBREAK
SATURDAY.
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
THE CLOUDS WITH THE FRONT SHOULD KEEP IT A BIT COOLER SATURDAY
ESPECIALLY IN THE NORTHWESTERN AREAS. THE STRONG SOUTHWESTERLY
FLOW...HIGH PRECIPITABLE WATER VALUES AND RELATIVELY HIGH CAPE
IMPLY THAT THERE SHOULD BE THUNDERSTORMS SATURDAY FROM LATE
MORNING IN THE WEST TO LATER AFTERNOON IN THE SOUTHEAST. SOME OF
THESE STORMS COULD BE STRONG TO SEVERE. NEARLY ALL OF OUR AREA IS
IN SLIGHT RISK FOR SEVERE THUNDERSTORMS SATURDAY. THERE IS SOME
MODESTLY STRONG MOISTURE FLUX AT 850 HPA IMPLYING GOOD LIFT MOVING
ACROSS THE STATE FROM ABOUT 15Z TO 00Z.
MOST MODELS IMPLY THE DEEP MOISTURE PLUME IS PUSHED TO OUR EAST
SATURDAY EVENING. DRIER AIR MOVES IN LATE EVENING WITH COOLER AIR
BEHIND IT. SHOULD BECOME QUITE COMFORTABLE OVERNIGHT AND NOTICEABLY
COOLER LOWS ON SUNDAY MORNING.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
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 TO SHOWERS SHOULD BE LOW PERHAPS BEST
CHANCE IN 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.
THUS AS ANOTHER WAVE APPROACHES FROM THE WEST IT WILL LIKELY PULL
SOME OF THE MOISTURE BACK INTO THE REGION LATE MONDAY INTO TUESDAY
INCREASING THE CHANCE OF SHOWERS AND THUNDERSTORMS.
THE 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 /18Z FRIDAY THROUGH WEDNESDAY/...
VFR CUMULUS WILL CONTINUE TO BUILD THRU THE AFTN WITH VISBYS IN
THE 6-8SM RANGE IN HZ DUE TO VERY MOIST BLYR /DEWPOINTS IN THE
UPPER 60S TO LOW 70S/. INCREASING INSTABILITY SHOULD COMBINE WITH
THE TERRAIN TO PROMOTE ISOLD TO SCT TSTM ACTIVITY WITH INITIATION
IN THE 17-20Z TIMEFRAME. WILL CONTINUE TO SHOW VCTS AND CB/S IN
THE TAFS GIVEN UNCERTAINTY IN EXACT LOCATION OF STORMS.
W/SW LLVL FLOW AHEAD OF APPROACHING COLD FRONT SHOULD LIMIT FOG/ST
FORMATION LATE TONIGHT...ESPECIALLY OVER THE WRN AREAS. ERN TAFS
HAVE A BETTER SHOT A GOING CLR/CALM SO COULD SEE SOME LCL
RESTRICTIONS BY DAYBREAK SATURDAY. THE COLD FRONT WILL CROSS THE
REGION LATER SATURDAY AND TRIGGER SCT STG TO SVR STORMS. THE WND
SHIFT SHOULD OCCUR FROM NW-SE BY SAT NIGHT.
OUTLOOK...
SAT...VFR. PM TSTM IMPACTS. SOME STORMS MAY BE SVR.
SUN...MVFR TO VFR. SHOWERS/ISOLD TSRA PSBL SOUTH.
MON...VFR.
TUES...VFR WITH PM SHOWERS/THUNDERSTORMS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ019-026>028-
035>037-041-042-045-046-049>053-056>059-063>066.
&&
$$
SYNOPSIS...GRUMM/STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...GRUMM/MARTIN
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1119 AM EDT FRI JUL 19 2013
.SYNOPSIS...
THE SUBTROPICAL RIDGE OVER THE EASTERN UNITED STATES WILL BEGIN ITS
SLOW EROSION OVER THE NEXT 2 DAYS. A VIGOROUS NORTHERN STREAM WAVE
SHOULD LOWER THE 500 HPA HEIGHTS AND PUSH A COLD FRONT INTO THE
REGION SATURDAY. IT WILL BE UNSEASONABLY WARM UNTIL THE FRONTAL
PASSAGE AND THE FRONT COULD TRIGGER SOME STRONG THUNDERSTORMS. THE
500 HPA TROUGH SHOULD BUILD OVER THE REGION SUNDAY INTO NEXT WEEK.
IT WILL BE SIGNIFICANTLY COOLER AND DRIER SUNDAY AND INTO THE
COMING WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
14-15Z...VISIBLE SATL LOOPS SHOW CU FIELD GOING UP ALONG ON THE
WRN AND CNTRL RIDGES...PARALLEL TO THE LLVL FLOW INDICATING BLYR
DESTABILIZATION. 14Z RUC ML CAPES ARE RUNNING BTWN 2-2.5K J/KG PER
SPC MESO PAGE. LATEST OBS STILL SHOW SOME 6-7SM HZ WITH SFC
DEWPOINTS IN THE LOW 70S. TEMPS SHOULD REACH THE LOW 90S IN THE
LWR SUSQ VLY BY 15Z WITH HEAT INDEXES APPROACHING 100F.
THE MAIN FCST CHALLENGE FOR TODAY CONTINUES TO BE FOCUSED ON THE
DEVELOPMENT/PLACEMENT OF DIURNAL CONVECTION. WITH AFTN TEMPS IN
THE UPPER 80S TO MID 90S AND SFC DEWPTS BTWN 65-70F...CAPES WILL
BE ROBUST AND EASILY SUPPORT UPDRAFTS. QUESTION REMAINS AS TO THE
EVOLUTION OF STORMS GIVEN NEBULOUS FORCING AND WARM 700MB TEMPS.
RAPID-REFRESH MESO MDL DATA IS STILL SHOWING THE GREATEST CVRG OF
TSTMS IN WRN/SWRN PA INTO WV. THIS MAY BE DUE TO A WK SHORTWAVE
ROTATING FROM KY INTO THE UPPER OH VLY ON THE NW PERIPHERY OF
RETREATING UPPER RIDGE. THE TERRAIN WILL ALSO ACT TO ENHANCE
LIFT. SOME CONVECTION IS ALSO PSBL NEAR THE LAKESHORE BOUNDARY
OVER THE NW MTNS. OVERALL...EXPECT ISOLD TO WDLY SCT TSTMS AS WE
GET LATER IN THE DAY. THE ENVIRONMENT SHOULD FAVOR MAINLY NON-SVR
MULTI-CELL STORMS GIVEN HIGH CAPE AND RELATIVELY WEAK 0-6KM SHEAR.
A HEAT ADVISORY REMAINS IN EFFECT FOR THE S-CENTRAL MTNS AND SUSQ
VLY UNTL 8PM. HEAT INDEXES/APPARENT TEMPERATURES ARE FCST TO REACH
THE 100 TO 104F RANGE...RESULTING IN AN ELEVATED RISK OF HEAT-
RELATED ILLNESS ESPECIALLY THOSE WITHOUT AC OR OUTDOORS FOR AN
EXTENDED PERIOD.
AFTN/EVE STORMS SHOULD WEAKEN INTO TONIGHT WITH THE LOSS OF
HEATING. IT WILL BE A WARM HUMID/MUGGY OVERNIGHT WITH INCREASED
SOUTHERLY FLOW AHEAD OF THE APPROACHING FRONTAL SYSTEM - WHICH
SHOULD REACH THE ST. LAWRENCE VLY AND LWR LKS REGIONS BY DAYBREAK
SATURDAY.
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
THE CLOUDS WITH THE FRONT SHOULD KEEP IT A BIT COOLER SATURDAY
ESPECIALLY IN THE NORTHWESTERN AREAS. THE STRONG SOUTHWESTERLY
FLOW...HIGH PRECIPITABLE WATER VALUES AND RELATIVELY HIGH CAPE
IMPLY THAT THERE SHOULD BE THUNDERSTORMS SATURDAY FROM LATE
MORNING IN THE WEST TO LATER AFTERNOON IN THE SOUTHEAST. SOME OF
THESE STORMS COULD BE STRONG TO SEVERE. NEARLY ALL OF OUR AREA IS
IN SLIGHT RISK FOR SEVERE THUNDERSTORMS SATURDAY. THERE IS SOME
MODESTLY STRONG MOISTURE FLUX AT 850 HPA IMPLYING GOOD LIFT MOVING
ACROSS THE STATE FROM ABOUT 15Z TO 00Z.
MOST MODELS IMPLY THE DEEP MOISTURE PLUME IS PUSHED TO OUR EAST
SATURDAY EVENING. DRIER AIR MOVES IN LATE EVENING WITH COOLER AIR
BEHIND IT. SHOULD BECOME QUITE COMFORTABLE OVERNIGHT AND NOTICEABLY
COOLER LOWS ON SUNDAY MORNING.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
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 TO SHOWERS SHOULD BE LOW PERHAPS BEST
CHANCE IN 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.
THUS AS ANOTHER WAVE APPROACHES FROM THE WEST IT WILL LIKELY PULL
SOME OF THE MOISTURE BACK INTO THE REGION LATE MONDAY INTO TUESDAY
INCREASING THE CHANCE OF SHOWERS AND THUNDERSTORMS.
THE 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 /15Z FRIDAY THROUGH TUESDAY/...
VFR CUMULUS WILL CONTINUE TO BUILD THRU THE AFTN WITH VISBYS IN
THE 6-8SM RANGE IN HZ DUE TO VERY MOIST BLYR /DEWPOINTS IN THE
UPPER 60S TO LOW 70S/. INCREASING INSTABILITY SHOULD COMBINE WITH
THE TERRAIN TO PROMOTE ISOLD TO SCT TSTM ACTIVITY WITH INITIATION
IN THE 17-20Z TIMEFRAME. WILL CONTINUE TO SHOW VCTS AND CB/S IN
THE TAFS GIVEN UNCERTAINTY IN EXACT LOCATION OF STORMS.
W/SW LLVL FLOW AHEAD OF APPROACHING COLD FRONT SHOULD LIMIT FOG/ST
FORMATION LATE TONIGHT...ESPECIALLY OVER THE WRN AREAS. ERN TAFS
HAVE A BETTER SHOT A GOING CLR/CALM SO COULD SEE SOME LCL
RESTRICTIONS BY DAYBREAK SATURDAY. THE COLD FRONT WILL CROSS THE
REGION LATER SATURDAY AND TRIGGER SCT STG TO SVR STORMS. THE WND
SHIFT SHOULD OCCUR FROM NW-SE BY SAT NIGHT.
OUTLOOK...
SAT...VFR. PM TSTM IMPACTS. SOME STORMS MAY BE SVR.
SUN...MVFR TO VFR. SHOWERS/ISOLD TSRA PSBL SOUTH.
MON...VFR.
TUES...VFR WITH PM SHOWERS/THUNDERSTORMS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ019-026>028-
035>037-041-042-045-046-049>053-056>059-063>066.
&&
$$
SYNOPSIS...GRUMM/STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...GRUMM/STEINBUGL
LONG TERM...GRUMM/MARTIN
AVIATION...CERU/STEINBUGL
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1039 PM EDT SAT JUL 20 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE SOUTHEAST WILL WEAKEN DURING THE REMAINDER OF
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/...
1015 PM UPDATE...THUNDERSTORMS PERSIST AT THIS HOUR IN THE VICINITY
OF A REMNANT GUST FRONT EXTENDING ACROSS THE LOWER SC PIEDMONT AND
SOUTH SIDE OF THE CHARLOTTE METRO. LATEST SPC MESOANALYSIS SHOWS
NEARLY 2000 J OF SBCAPE STILL UNINHIBITED JUST SOUTH OF THIS
BOUNDARY...AS WELL AS A THERMAL GRADIENT IN THE SAME AREA THAT IS
LIKELY PROVIDING ENOUGH FORCING TO GET PARCELS GOING. LIGHT SLY FLOW
ON THE S SIDE OF THE BDY WILL CONTINUE TO REINFORCE THE GRADIENT AND
IT MAY TAKE SOME TIME FOR THE REMNANT INSTABILITY TO BE CONSUMED.
LATEST HRRR SUPPORTS THIS CONCEPT AS WELL AS THE SCHC POP WHICH HAS
BEEN MAINTAINED OVERNIGHT FOR MOST OF THE CWFA...AS IT FEATURES A
COUPLE OF ISOLATED CELLS HERE AND THERE...ESPECIALLY NEAR THE BLUE
RIDGE.
ON A FINAL NOTE...PATCHY FOG ALREADY DEVELOPING AT SOME
SITES...PRIMARILY SITES WHICH SAW HEAVY RAIN THIS AFTN. FOLLOWING
THAT THINKING THE MAIN AREA OF CONCERN WOULD BE THE FOOTHILLS AND
UPPER PIEDMONT. AT THIS TIME THE REPORTING SITES ARE TOO SCATTERED
TO NEED A DENSE FOG ADVY...AND NAM SOUNDINGS ARE NOT SUPPORTIVE OF
WIDESPREAD DENSE FOG ANYWAY. HOWEVER...IT BEARS MONITORING AND WILL
INFORM INCOMING SHIFT OF THIS CONCERN.
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 /03Z SUNDAY THROUGH THURSDAY/...
AT KCLT...PATTERN LARGELY THE SAME AS LAST NIGHT SO PERSISTENCE WAS
KEY TO FCST. LLVL MOISTURE ONCE AGAIN ABUNDANT AND GUIDANCE
CONSENSUS IS LOW MVFR EARLY SUNDAY. WOULD NOT BE SURPRISED TO SEE
IFR AROUND DAYBREAK THOUGH LACK OF RAINFALL IN THE IMMEDIATE
VICINITY TODAY MAKES THAT A BIT LESS LIKELY. IMPROVEMENT LIKELY TO
BE SOMEWHAT SLOW AFTER SUNRISE...WITH PERSISTENT LOW CIGS DELAYING
THE ONSET OF DIURNAL INSTABILITY /CU AND TS DEVELOPMENT/. DEEPENING
MOISTURE PUTS AFTN THUNDER CHANCES A BIT MORE THAN USUAL...BUT STILL
ONLY WORTHY OF PROB30. WINDS WILL REMAIN LIGHT SOUTHERLY.
ELSEWHERE...VFR DEBRIS FROM AFTN TSTMS WILL LINGER THIS
EVENING...BUT WITH VERY MOIST CONDITIONS CONTINUING...LOW MVFR OR
IFR CIGS WILL BEGIN TO DEVELOP OVER MUCH OF THE REGION BY MIDNIGHT.
GUIDANCE GENERALLY IN AGREEMENT WHICH LENDS CONFIDENCE TO A
RESTRICTIVE FCST MUCH LIKE THE CONDITIONS EARLY SATURDAY MRNG. CIGS
WILL BE THE MAIN FACTOR WITH DENSE FOG LOOKING MOST LIKELY IN THE
MTN VALLEYS /INCLUDING KAVL/. THE LOW CIGS WILL BE SLOW TO IMPROVE
BUT SOUTHERLY WINDS WILL PROVIDE WEAK UPSLOPE FORCING TO ENHANCE
PRECIP COVERAGE FROM MODEST DIURNAL INSTABILITY. PRECIP LIKELY ACRS
THE MTNS AND FOOTHILLS BY LATE MRNG.
OUTLOOK...MOIST SOUTHWESTERLY FLOW CONTINUES INTO THE EARLY WEEK.
THIS WILL HELP DRIVE SHOWERS AND THUNDERSTORMS...MAINLY IN THE
AFTERNOON AND EVENING...AND LIKELY CAUSE RESTRICTIVE CIGS/VSBYS
EARLY EACH MORNING.
CONFIDENCE TABLE...
02-08Z 08-14Z 14-20Z 20-02Z
KCLT MED 78% MED 72% HIGH 86% HIGH 100%
KGSP LOW 56% LOW 56% HIGH 86% HIGH 100%
KAVL MED 75% MED 76% MED 61% MED 64%
KHKY LOW 55% LOW 59% LOW 58% HIGH 100%
KGMU LOW 52% LOW 55% LOW 59% HIGH 100%
KAND MED 79% LOW 52% HIGH 86% 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...PAT
NEAR TERM...JAT/WIMBERLEY
SHORT TERM...LGL
LONG TERM...LGL
AVIATION...WIMBERLEY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1037 PM EDT SAT JUL 20 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE SOUTHEAST WILL WEAKEN DURING THE REMAINDER OF
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/...
1015 PM UPDATE...THUNDERSTORMS PERSIST AT THIS HOUR IN THE VICINITY
OF A REMNANT GUST FRONT EXTENDING ACROSS THE LOWER SC PIEDMONT AND
SOUTH SIDE OF THE CHARLOTTE METRO. LATEST SPC MESOANALYSIS SHOWS
NEARLY 2000 J OF SBCAPE STILL UNINHIBITED JUST SOUTH OF THIS
BOUNDARY...AS WELL AS A THERMAL GRADIENT IN THE SAME AREA THAT IS
LIKELY PROVIDING ENOUGH FORCING TO GET PARCELS GOING. LIGHT SLY FLOW
ON THE S SIDE OF THE BDY WILL CONTINUE TO REINFORCE THE GRADIENT AND
IT MAY TAKE SOME TIME FOR THE REMNANT INSTABILITY TO BE CONSUMED.
LATEST HRRR SUPPORTS THIS CONCEPT AS WELL AS THE SCHC POP WHICH HAS
BEEN MAINTAINED OVERNIGHT FOR MOST OF THE CWFA...AS IT FEATURES A
COUPLE OF ISOLATED CELLS HERE AND THERE...ESPECIALLY NEAR THE BLUE
RIDGE.
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 /03Z SUNDAY THROUGH THURSDAY/...
AT KCLT...PATTERN LARGELY THE SAME AS LAST NIGHT SO PERSISTENCE WAS
KEY TO FCST. LLVL MOISTURE ONCE AGAIN ABUNDANT AND GUIDANCE
CONSENSUS IS LOW MVFR EARLY SUNDAY. WOULD NOT BE SURPRISED TO SEE
IFR AROUND DAYBREAK THOUGH LACK OF RAINFALL IN THE IMMEDIATE
VICINITY TODAY MAKES THAT A BIT LESS LIKELY. IMPROVEMENT LIKELY TO
BE SOMEWHAT SLOW AFTER SUNRISE...WITH PERSISTENT LOW CIGS DELAYING
THE ONSET OF DIURNAL INSTABILITY /CU AND TS DEVELOPMENT/. DEEPENING
MOISTURE PUTS AFTN THUNDER CHANCES A BIT MORE THAN USUAL...BUT STILL
ONLY WORTHY OF PROB30. WINDS WILL REMAIN LIGHT SOUTHERLY.
ELSEWHERE...VFR DEBRIS FROM AFTN TSTMS WILL LINGER THIS
EVENING...BUT WITH VERY MOIST CONDITIONS CONTINUING...LOW MVFR OR
IFR CIGS WILL BEGIN TO DEVELOP OVER MUCH OF THE REGION BY MIDNIGHT.
GUIDANCE GENERALLY IN AGREEMENT WHICH LENDS CONFIDENCE TO A
RESTRICTIVE FCST MUCH LIKE THE CONDITIONS EARLY SATURDAY MRNG. CIGS
WILL BE THE MAIN FACTOR WITH DENSE FOG LOOKING MOST LIKELY IN THE
MTN VALLEYS /INCLUDING KAVL/. THE LOW CIGS WILL BE SLOW TO IMPROVE
BUT SOUTHERLY WINDS WILL PROVIDE WEAK UPSLOPE FORCING TO ENHANCE
PRECIP COVERAGE FROM MODEST DIURNAL INSTABILITY. PRECIP LIKELY ACRS
THE MTNS AND FOOTHILLS BY LATE MRNG.
OUTLOOK...MOIST SOUTHWESTERLY FLOW CONTINUES INTO THE EARLY WEEK.
THIS WILL HELP DRIVE SHOWERS AND THUNDERSTORMS...MAINLY IN THE
AFTERNOON AND EVENING...AND LIKELY CAUSE RESTRICTIVE CIGS/VSBYS
EARLY EACH MORNING.
CONFIDENCE TABLE...
02-08Z 08-14Z 14-20Z 20-02Z
KCLT MED 78% MED 72% HIGH 86% HIGH 100%
KGSP LOW 56% LOW 56% HIGH 86% HIGH 100%
KAVL MED 75% MED 76% MED 61% MED 64%
KHKY LOW 55% LOW 59% LOW 58% HIGH 100%
KGMU LOW 52% LOW 55% LOW 59% HIGH 100%
KAND MED 79% LOW 52% HIGH 86% 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...PAT
NEAR TERM...JAT/WIMBERLEY
SHORT TERM...LGL
LONG TERM...LGL
AVIATION...WIMBERLEY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
441 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/...
415 PM UPDATE...WILL MAINTAIN POPS LARGELY AS-IS. SPC MESOANALYSIS
SHOWS SBCAPE IN 2500-3500 J RANGE ACRS THE AREA. BEST COVERAGE ATTM
IS IN THE MTNS AND CONGESTED CU ARE ALIGNED ALONG RIDGETOPS SO THIS
COVERAGE IS STILL CAPABLE OF INCREASING FURTHER. REVISED PIEDMONT
POPS SUCH THAT BEST CHANCES ARE ALIGNED WITH THE BAND OF BETTER CU
FROM AROUND ELBERTON TO SALISBURY. THERE DOES APPEAR TO BE AN AREA
OF LOCAL SCALE SUBSIDENCE IN THE MIDLANDS SUPPRESSING CU GROWTH.
THIS IS WORKING NORTHWESTWARD...BUT THE CU IN THAT BAND ARE STILL
GROWING SO SOME CHANCE REMAINS IN THE PIEDMONT. 17Z HRRR DEVELOPS
CELLS AROUND SUNSET IN THE MTNS WHICH MARCH ACROSS THE NRN THIRD OF
THE CWFA THRU 03Z APPARENTLY ALONG AN OUTFLOW BOUNDARY. THIS IS
RATHER UNUSUAL BUT LAST NIGHT CELLS DID FIRE ALONG OUTFLOW IN THE
VERY MOIST AIR AT THAT TIME OF DAY. WILL MONITOR TRENDS IN SHORT
TERM GUIDANCE.
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 /21Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT...GUIDANCE IS NOT VERY SUPPORTIVE OF RESTRICTIONS...CARRYING
ONLY LOW VFR VSBY AT DAYBREAK SATURDAY. ROBUST INSTABILITY WILL
SUPPORT ENOUGH LATE AFTERNOON AND EARLY EVENING CONVECTION TO CARRY
A MENTION IN THE TAF...WITH MVFR CIG AND VSBY RESTRICTIONS POSSIBLE.
LIGHT SSW WINDS WILL PERSIST.
ELSEWHERE...A BLEND OF ADJMAV AND ADJMET GUIDANCE FAVORS MVFR VSBY
IN DAYBREAK FOG AT KAVL...WITH LOW VFR VSBY AT FOOTHILLS SITES. THE
BEST BET FOR CIGS WILL BE IN THE MOUNTAINS...WHERE MODEL TIME
HEIGHTS SUGGEST A BORDERLINE MVFR CIG AT KAVL THIS AFTERNOON/ OF
COURSE...ANY SITE THAT HAS A THUNDERSTORM MOVE OVERHEAD THIS
AFTERNOON OR EVENING WILL HAVE A CHANCE OF MVFR CIG AND VSBY
RESTRICTIONS DURING THE STORM...AND AGAIN AT DAYBREAK IN A RAIN
MOISTENED ATMOSPHERE. LIGHT WINDS WILL FAVOR THE SSW...EXCEPT IN THE
MOUNTAINS TONIGHT WHERE THEY WILL VEER TO THE NW 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 100% HIGH 98% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 96% HIGH 100%
KAVL LOW 56% LOW 53% MED 67% MED 61%
KHKY HIGH 100% HIGH 100% HIGH 86% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 96% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 94% 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...JAT
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
931 PM CDT SAT JUL 20 2013
.UPDATE...
UPDATED TO INCREASE POPS IN CENTRAL SOUTH DAKOTA WITH QUITE A FEW
STORMS SHOWN ON RADAR. ALSO...SOME NEW DEVELOPMENT SHOWING UP IN
NORTH CENTRAL SOUTH DAKOTA.
&&
.PREVIOUS DISCUSSION...
.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...
00Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
VFR CONDITIONS ARE EXPECTED AT ALL TAF LOCATIONS THROUGH TONIGHT
AND SUNDAY. A FEW SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS
THE REGION TONIGHT AND SUNDAY AND MAY AFFECT THE TERMINALS AT OR
IN THE VICINITY. WILL WATCH FOR POSSIBLE AMENDMENTS.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...MOHR
SHORT TERM...SD
LONG TERM...WISE
AVIATION...MOHR
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
705 PM CDT SAT JUL 20 2013
.UPDATE...
00Z AVIATION DISCUSSION UPDATED BELOW.
&&
.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...
00Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
VFR CONDITIONS ARE EXPECTED AT ALL TAF LOCATIONS THROUGH TONIGHT
AND SUNDAY. A FEW SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS
THE REGION TONIGHT AND SUNDAY AND MAY AFFECT THE TERMINALS AT OR
IN THE VICINITY. WILL WATCH FOR POSSIBLE AMENDMENTS.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...MOHR
SHORT TERM...SD
LONG TERM...WISE
AVIATION...MOHR
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1049 PM MDT THU JUL 18 2013
.UPDATE...
ISSUED AT 821 PM MDT THU JUL 18 2013
02Z SURFACE ANALYSIS SHOWED COOL FRONT/TROUGH EXITING CWA. DIURNAL
CYCLE TAKING IT/S TOLL ON TSRA WITH ACTIVITY ABOUT DONE SAVE FOR
SOME ANVIL DEBRIS. LOOKS PRETTY QUITE OVERNIGHT PER 00Z RAP AND
00Z KUNR SOUNDING. WILL LEAVE SMALL POPS NEAR THE NE BORDER GIVEN
NUMEROUS BOUNDARIES AND PROXIMITY TO 850-700MB FRONT AND ELEVATED
INSTABILITY.
&&
.SHORT TERM...THIS EVENING THROUGH FRIDAY NIGHT
ISSUED AT 221 PM MDT THU JUL 18 2013
NORTHERN STREAM IMPULSE CONTINUES TO ADVECT/PROPAGATE
TO THE EAST ACROSS SOUTHERN SK/MB WITH AN ORPHANING TROUGH AXIS OVER
THE SOUTHERN FA. MOISTURE POOLING JUST BEHIND THE TROUGH COUPLED
WITH DIURNAL HEATING/SOUTHERN BH CONVERGENCE/AND WEAK LSA HAS
SUPPORTED A CLUSTER OF THUNDERSTORMS OVER THE SOUTHERN BH...WITH
ADDITIONAL CELLS EXPECTED TO INITIATE ACROSS THE EASTERN AND
SOUTHERN FA THIS AFTERNOON AND EVENING...AS THE TROUGH PROGRESSES SE
AND INHIBITION WEAKENS PER DIURNAL HEATING. CELLS WILL CONTINUE TO
FIGHT THE CAPPING INVERSION ACROSS THE EASTERN AND SE FA WITH FAIRLY
WARM TEMPS ALOFT HIGHLY LIMITING CAPE. MARGINAL TO WEAK DEEP LAYER
SHEAR SHOULD PREVENT MOST STORMS FROM ORGANIZATION...REMAINING PULSE
DRIVEN. WIDESPREAD MASSIVE CONUS RIDGE WILL EVENTUALLY FLATTEN AS A
STRONGER MORE PRONOUNCED UPPER SHORTWAVE DIGS SE INTO THE GREAT
LAKES THROUGH FRIDAY. MEANWHILE...LOCAL DEEP LAYER FLOW WILL TURN
NW...WITH IMPULSES ORIGINATING FROM THE CLOSED NE PAC UPPER LOW
EXPECTED IN THE FLOW. AFOREMENTIONED TROUGH AND ASSOCIATED LL
MOISTURE BUBBLE WITH THETA-E POOLING WILL RESIDE OVERT THE SW FA
THROUGH FRIDAY NIGHT. FORECAST MODELS ARE IN RATHER STRONG AGREEMENT
THAT A WEAK...BUT SUFFICIENT IMPULSE WILL PASS THROUGH THE FLOW FRI
NIGHT...WITH REFLECTED FRONT SIDE SOUTHERLY FLOW /INDICATED WELL AT
H7/ EXPECTED TO SUPPORT A PERIOD OF POS THETA-E ADV UNDER FAIRLY
STEEP MID LEVEL LAPSE RATES. GIVEN AMPLE LL SLIGHTLY ELEVATED
MOISTURE IN PLACE...SHOWER AND THUNDERSTORMS CHANCES LOOK GOOD OVER
THE REGION...WITH THE POSSIBLY OF A SMALL MCS. THERE IS A SMALL
POTENTIAL FOR A SEVERE STORM OR TWO FRI NIGHT. PROGGED DEEP LAYER
SHEAR UTILIZING AN ELEVATED PARCEL SUGGEST 30 TO 45 KNOTS OF BULK
SHEAR...WITH MU CAPE AOA 1000 J/KG ACROSS THE FAR SW FA PER NAM
DATA. THIS WILL HAVE TO WATCHED.
RETAINED LOW CHANCE POPS ACROSS THE SE FA THROUGH THIS
EVENING...WITH LOW SLIGHTS ACROSS THE FAR SW LATE TONIGHT FOR
POSSIBLE ELEVATED SHOWERS...WHICH MAY END UP AS JUST VIRGA. ALSO
RETAINED LOW SLIGHTS ACROSS THE SW FA FRI GIVEN THE COLLOCATION OF
THE LL THETA-E PLUME. HOWEVER...MODEL DATA SUGGEST THAT THIS PLUME
OF MOISTURE WILL REMAIN ELEVATED. HENCE...ANY MODEL GENERATED QPF IN
THIS PERIOD MAY BE FROM AN ACCAS PLUME. DID TREND POPS UP ACROSS THE
SW HALF FRIDAY NIGHT GIVEN ABOVE CONCERNS.
AS FOR TEMPS...WARM TO HOT CONDITIONS CAN BE EXPECTED MOST PLACES
FRIDAY...ALTHOUGH 5 TO 10 DEGREES COOLER THAN TODAY/S TEMPS AS THE
THERMAL RIDGE SHIFTS EAST. LOWS GENERALLY IN THE 60S CAN BE
EXPECTED BOTH TONIGHT AND FRIDAY NIGHT.
&&
.LONG TERM...SATURDAY THROUGH THURSDAY
ISSUED AT 221 PM MDT THU JUL 18 2013
BROAD...RELATIVELY FLAT LONG WAVE RIDGE HAS
RETROGRESSED TO ABOUT 105W WITH NEXT UPSTREAM TROF NEAR 130W. RIDGE
IS FCST BY BOTH GFS AND ECMWF MODELS TO CONTINUE MOVING W WARD TO
NEAR THE PAC COAST BY 12Z SATURDAY AND TO NEAR 130W BY 12Z SUNDAY.
THE TREND IS THEN FOR IT TO MOVE SLOWLY E WARD AND AMPLIFY A BIT BY
12Z WED. THIS PLACES WEAK WNW FLOW OVER OUR CWA DURING ALL OF THE
LONG TERM PERIOD. SEVERAL WEAK SHORT WAVES WILL MOVE ACROSS THE AREA
IN THIS FLOW. TIMING OF THESE WAVES IS HANDLED VERY DIFFERENTLY BY
EACH OF THE MODELS...SO HAVE NOT TRIED TO PIN THEM DOWN TOO CLOSELY
IN POPS.
STAYED CLOSE TO GUIDANCE IN TEMPS WITH LITTLE REASON TO DEPART.
AS NOTED BY PREVIOUS SHIFT...EXTENDED GRID INITIALIZATION PLACED DEW
POINTS THE LOOK TOO HIGH OVER OUR WY COUNTIES. THE INITIALIZATION IS
NOT HANDLING DIURNAL DEW POINT TRENDS WELL...SO MOST NIGHT TIME DEW
POINTS WERE LOWERED CLOSER TO GFS AND EURO MOS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1045 PM MDT THU JUL 18 2013
ISOLATED TSRA ARE POSSIBLE FOR THE REST OF TONIGHT NEAR THE NE
BORDER. AFTER A QUIET MORNING...ADDITIONAL TSRA WILL DEVELOP OVER
WY FRIDAY AFTERNOON...SPREADING EAST/NORTH ACROSS SD LATER FRIDAY
AFTERNOON/NIGHT. VFR CONDITIONS WILL PREVAIL OUTSIDE OF
TSRA...EXCEPT FOR LOCAL MVFR CIGS/VSBYS IN/NEAR STORMS.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
UPDATE...HELGESON
SHORT TERM...JC
LONG TERM...BARBER
AVIATION...HELGESON
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
953 PM CDT SAT JUL 20 2013
.UPDATE...
DIURNALLY DRIVEN SHOWERS HAVE DISSIPATED ACROSS WEST CENTRAL TX
BUT WE CONTINUE TO SEE ECHOES ROTATING TO THE NORTHWEST AROUND
THE MID/UPPER LEVEL CYCLONE NEAR THE BIG BEND. POPS WERE REMOVED
ACROSS MOST OF THE FORECAST AREA THROUGH THE REMAINDER OF THE
OVERNIGHT PERIOD BUT I DID RETAIN A SLIGHT CHANCE OF SHOWERS IN
THE SOUTH...MAINLY CROCKETT AND SUTTON COUNTIES DUE TO THE
PROXIMITY OF THIS UPPER LOW. BOTH THE 3K TTU WRF AND HRRR DEPICT
WEAK CONVECTION MOVING INTO THIS AREA AFTER MIDNIGHT.
OTHERWISE...ONLY MINOR MODIFICATIONS WERE MADE TO THE INHERITED
FORECAST.
JOHNSON
&&
.PREV DISCUSSION... /ISSUED 633 PM CDT SAT JUL 20 2013/
DISCUSSION...
SEE AVIATION DISCUSSION BELOW/
AVIATION...
CURRENTLY ISOLATED SHOWERS HAVE DEVELOPED ACROSS
MASON...MCCULLOUGH...MENARD...COLEMAN...SHACKELFORD AND SUTTON
COUNTIES. AN ISOLATED SHOWER WAS NOTED JUST NORTH OF SAN ANGELO.
MOST OF THESE SHOWERS ARE EXPECTED TO DISSIPATE AFTER SUNSET.
ON SUNDAY THERE IS POTENTIAL FOR ISOLATED SHOWERS TO REDEVELOP...
CAUSED BY AFTERNOON HEATING THAT WILL CAUSE WARM AIR TO RISE
THROUGH A WEAKLY CAPPED ATMOSPHERE THAT HAS MOIST AIR IN THE
LOWEST 5K FEET. THE MOST LIKELY SHOWER AREAS WILL BE ACROSS
MASON...KIMBLE... SUTTON...MENARD AND SAN SABA COUNTIES.
HOWEVER...MOSTLY VFR CONDITIONS WILL PREVAIL THE NEXT 24 HOURS
ACROSS THE FORECAST AREA.
PREV DISCUSSION... /ISSUED 349 PM CDT SAT JUL 20 2013/
SHORT TERM...
/TONIGHT AND SUNDAY/
.ISOLATED BRIEF SHOWERS AND THUNDERSTORMS INTO SUNDAY...
MOIST LOW LEVEL MOISTURE WILL CONTINUE WITH A WEAKLY OR UNCAPPED
ATMOSPHERE INTO SUNDAY. MOST STORMS EXPECTED TO DEVELOP MID AND
LATE AFTERNOON UNDER MAXIMUM HEATING...THEN DISSIPATE AFTER SUNSET.
HOWEVER...A FEW STORMS MAY LAST LONGER OVER SOUTHERN SECTIONS ALONG
THE I-10 CORRIDOR AT NIGHT WHERE THE THE UPPER RIDGE IS WEAKEST.
BRIEF HEAVY RAIN IS POSSIBLE IN SLOW MOVING STORMS.
LONG TERM...
THERE IS A SLIGHT CHANCE FOR SHOWERS AND THUNDERSTORMS ACROSS
SOUTHERN SECTIONS ON MONDAY WITH DRY AND WARMER WEATHER FOR THE
REMAINDER OF NEXT WEEK.
A WEAK UPPER LEVEL LOW WILL BE SITUATED NEAR THE BIG BEND SUNDAY
EVENING AND WILL DRIFT SOUTHWEST INTO NORTHERN MEXICO BY TUESDAY
AFTERNOON. WE WILL STILL SEE A DECENT AMOUNT OF LOW AND MID LEVEL
MOISTURE AROUND...ESPECIALLY ACROSS SOUTHERN SECTIONS ON MONDAY.
KEPT INHERITED LOW POPS INTACT MAINLY OVER THE NORTHWEST HILL
COUNTRY AND NORTHERN EDWARDS PLATEAU MONDAY AND MONDAY EVENING
WHERE WIDELY SCATTERED SHOWERS AND FEW THUNDERSTORMS WILL BE
POSSIBLE. HIGHS ON MONDAY WILL BE MAINLY IN THE LOW TO MID 90S
WITH A FEW READINGS IN THE UPPER 90S ACROSS THE NORTHERN BIG
COUNTRY.
AN UPPER LEVEL RIDGE WILL BUILD SOUTHEAST ACROSS THE SOUTHERN
ROCKIES AND INTO CENTRAL TEXAS TUESDAY THROUGH THE END OF THE
WEEK. THE ECMWF DOES SHUNT THE RIDGE BACK TO THE WEST FRIDAY
INTO SATURDAY AS A SHORT WAVE DROPS SOUTHEAST FROM THE NORTHERN
ROCKIES...WITH AN ASSOCIATED WEAK COLD FRONT ENTERING THE AREA.
THE GFS MAINTAINS A STRONGER RIDGE WITH THE FRONT REMAINING NORTH
OF THE AREA. KEPT A DRY FORECAST GOING FOR NOW GIVEN THESE MODEL
DISCREPANCIES. HIGH TEMPERATURES WILL WARM FROM THE LOW TO MID 90S
ON TUESDAY...TO THE MID AND UPPER 90S WEDNESDAY THROUGH SATURDAY.
OVERNIGHT LOWS WILL MAINLY BE IN THE LOWER 70S THROUGH THE PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 71 93 72 94 74 / 5 10 10 10 10
SAN ANGELO 70 93 72 94 74 / 10 20 10 20 10
JUNCTION 70 92 72 93 73 / 10 30 20 20 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
25
AREA FORECAST DISCUSSION...UPDATED
NWS AUSTIN/SAN ANTONIO TX
1231 PM CDT FRI JUL 19 2013
.DISCUSSION...
SEE AVIATION FOR THE 18Z TAF DISCUSSION.
&&
.AVIATION...
AT 17Z AN AREA OF SHOWERS AND THUNDERSTORMS WAS LOCATED OVER NORTHEAST
TEXAS MOVING SOUTHWEST AT 15 MPH. THE LATEST RUC13 AND EXTRAPOLATION
OF CURRENT MOVEMENT SUGGESTS CONVECTION WILL IMPACT KAUS AS EARLY AS
23Z. THUS WILL GO WITH A 3 HOUR TEMPO GROUP AT KAUS. ISOLATED CONVECTION
IS ALSO EXPECTED ALONG THE INLAND MOVING SEA-BREEZE BOUNDARY THIS
AFTERNOON. THE ISOLATED NATURE OF THIS ACTIVITY DOES NOT WARRANT
INCLUSION IN THE KSAT OR KSSF TAFS ATTM. OTHERWISE VFR CONDITIONS
WILL PREVAIL THIS AFTERNOON AND EVENING...WITH MVFR IN AND NEAR
TSTMS. MVFR CIGS WILL FORM AT THE I-35 TERMINALS BETWEEN 09Z AND
10Z...REACHING KDRT BY 11Z. CIGS WILL IMPROVE TO VFR BY 17Z WITH
ISOLATED AFTERNOON CONVECTION EAST OF A KBMQ...KSAT...KFTN LINE.
SFC WINDS WILL BE SOUTHERLY AT 5 TO 10 KTS WITH CONVECTIVE OUTFLOW
GUSTS OF 20 TO 30 KTS POSSIBLE THIS AFTERNOON AND EVENING.
&&
.PREV DISCUSSION... /ISSUED 630 AM CDT FRI JUL 19 2013/
AVIATION...
STRATUS DECK ACROSS THE HILL COUNTRY AND ADJACENT AREAS WILL
CONTINUE TO EXPAND THROUGH THE NEAR-DAYBREAK HOURS. CIG BASES WILL
MOSTLY BE LOW MVFR WITH OCCASIONAL DROPS TO IFR BEFORE
LIFTING/SCATTERING OUT TO VFR AROUND 15-16Z AT KAUS/KSAT/KSSF AND
17Z AT KDRT. LIGHT SFC WINDS THIS MORNING WILL BECOME SE-SLY
MOSTLY AOB 10KTS THROUGH THE AFTERNOON. ISOLATED SHRA/TSRA ARE
POSSIBLE ACROSS FAR WESTERN PORTIONS OF THE REGION...AS WELL AS
GENERALLY EAST OF A LINE FROM KBMQ TO KHYI TO KVCT...MAINLY DURING
THE AFTERNOON HOURS. HOWEVER...AREAL COVERAGE IS TOO LOW TO WARRANT
EXPLICIT MENTION OF IMPACTS AT KAUS.
PREV DISCUSSION... /ISSUED 359 AM CDT FRI JUL 19 2013/
SHORT TERM (TODAY THROUGH SATURDAY)...
A THIN SUBTROPICAL RIDGE AXIS IS OVER SOUTH CENTRAL TEXAS BETWEEN
A TUTT LOW OVER THE CENTRAL GULF COAST AND AN UPPER LEVEL LOW OVER
SONORA STATE IN NORTHWESTERN MEXICO. AREA RADARS SHOW SCATTERED
SHOWERS OVER THE SERRANIAS DEL BURRO AND ISOLATED STREAMER SHOWERS
OVER THE COASTAL PLAINS. HAVE SLIGHT CHANCE POPS TODAY INTO THIS
EVENING FOR OUR EASTERN COUNTIES AS THE TUTT LOW APPROACHES WHILE
INTERACTING WITH THE SEABREEZE. ALSO HAVE POPS FOR OUR FAR WESTERN
AREA AS SOME STORMS MAY COME OFF THE SERRANIAS DEL BURROS. ON
SATURDAY...THE TUTT LOW MOVES A LITTLE FURTHER WEST TO THE UPPER
TEXAS COAST/SOUTHEASTERN TEXAS TO ENHANCE THE SEABREEZE. POPS
INCREASE TO LOW END CHANCE ACROSS THE EAST. HIGHS WARM SLIGHTLY
TODAY AND THEN LEVEL OFF MOST AREAS OR EVEN COOL SLIGHTLY IN THE
FAR EAST ON SATURDAY.
LONG TERM (SATURDAY NIGHT THROUGH THURSDAY)...
THE TUTT LOW WEAKENS INTO A SHEAR AXIS OVER EASTERN INTO SOUTHERN
TEXAS BY SUNDAY WHILE A SHORT-WAVE ROTATES AROUND THE SONORAN
UPPER LOW TOWARD THE BIG BEND AND SLOWLY DEVELOPS INTO AN UPPER
LOW ITSELF LATE SUNDAY INTO MONDAY. THE ECMWF/UKMET DEPICT THIS
DEVELOPMENT OVER THE BIG BEND STRONGER WHILE THE GFS/GEM/NAVGEM
ARE MUCH WEAKER OR NON EXISTENT. WILL GO WITH AN IN BETWEEN
SOLUTION AND HAVE GONE WITH SLIGHT CHANCE POPS FOR ALL AREAS
SUNDAY AND AGAIN MONDAY. HOWEVER...POPS MAY HAVE TO BE RAISED WITH
INCREASING QPF OUT WEST IF THE STRONGER ECMWF/UKMET VERIFY. ON
TUESDAY...THE SUBTROPICAL RIDGE REASSERTS ITSELF WITH SLIGHT
CHANCE POPS ONLY IN THE FAR WEST. FOR THE REMAINDER OF NEXT WEEK
INTO NEXT WEEKEND...THE SUBTROPICAL RIDGE DOMINATES WITH NO POPS
AND ABOVE AVERAGE DAYTIME TEMPERATURES.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 73 96 74 96 75 / 20 30 20 20 10
AUSTIN BERGSTROM INTL AIRPORT 71 96 71 96 73 / 20 20 20 20 10
NEW BRAUNFELS MUNI AIRPORT 70 95 71 96 72 / 10 20 10 20 10
BURNET MUNI AIRPORT 72 94 72 94 73 / 10 20 10 20 10
DEL RIO INTL AIRPORT 74 93 74 94 76 / 10 10 10 20 10
GEORGETOWN MUNI AIRPORT 72 95 72 94 73 / 20 30 20 20 10
HONDO MUNI AIRPORT 71 96 73 96 74 / 10 10 10 20 10
SAN MARCOS MUNI AIRPORT 71 95 72 96 74 / 20 20 10 20 10
LA GRANGE - FAYETTE REGIONAL 73 95 73 95 76 / 20 30 20 30 10
SAN ANTONIO INTL AIRPORT 74 95 74 95 76 / 10 20 10 20 10
STINSON MUNI AIRPORT 73 95 73 96 74 / 10 20 10 20 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...13
SYNOPTIC/GRIDS...02
PUBLIC SERVICE/DATA COLLECTION...30
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1155 PM CDT THU JUL 18 2013
.DISCUSSION...
SEE THE 06Z AVIATION DISCUSSION BELOW.
40
&&
.AVIATION...
NOT MUCH CHANGE FROM THE PREVIOUS DISCUSSION AT 00Z. VFR
CONDITIONS EXPECTED FOR MOST LOCATIONS FROM KCXO SOUTH TO THE
COAST...WITH THE EXCEPTION AT KUTS TOWARD SUNRISE. ANY SHOWERS OR
THUNDERSTORMS THAT DO DEVELOP SHOULD DISSIPATE BY EARLY FRIDAY
EVENING.
40
&&
.PREV DISCUSSION... /ISSUED 858 PM CDT THU JUL 18 2013/
UPDATE...
SEE EVENING UPDATE.
DISCUSSION...
A VARIETY OF CONDITIONS ACROSS SE TX THIS EVENING. SFC DEW POINTS
VARY WILDLY ACROSS THE AREA WITH MID 50S OVER THE EXTREME NW
ZONES...MID TO UPPER 60S CENTRAL AND LOWER TO MID 70S ALONG THE
COAST AND OVER THE NORTHEAST. CONVECTION OVER THE CWA HAS WANED
AND THE STORMS TO THE EAST ALSO SHOWS SIGNS OF WEAKENING. THE
LATEST RAP SUPPORTS OTHER SHORT TERM MODELS WITH CONVECTION
GENERALLY ENDING WITH POSSIBLE REDEVELOPMENT ALONG THE COAST PRIOR
TO SUNRISE. 00Z SOUNDINGS SHOW PW VALUES NEAR 1.9 INCHES AND 1.7
INCHES AT CRP. 850 MB MOISTURE WAS HIGHER OVER LOUISIANA AND DRIER
TOWARD THE MIDDLE AND LOWER TEXAS COAST. A WEAK 850 MB LOW WAS
LOCATED OVER EASTERN LOUISIANA WITH A WEAKNESS ALOFT ALSO OVER
EASTERN LA. THIS WEAKNESS IS PROGGED TO SHIFT WEST ON FRIDAY AND
WILL PROBABLY BRING THE EASTERN HALF OF THE AREA SLIGHTLY HIGHER
RAIN CHANCES. WILL ISSUE NEW ZONES TO CLEAN UP EVENING WORDING
ONCE THE THREAT FOR CONVECTION ENDS. 43
PREV DISCUSSION... /ISSUED 647 PM CDT THU JUL 18 2013/
DISCUSSION...
SEE THE 00Z AVIATION DISCUSSION BELOW.
40
AVIATION...
THE MAIN WEATHER FEATURES AFFECTING SE TX AT 2330Z THIS EVENING
WERE THE SURFACE HIGH PRESSURE RIDGE EXTENDING INTO THE AREA FROM
KY AND WHAT LOOKED TO BE A TUTT LOW INLAND OF THE FL AND AL
COASTS. THE DRY MID AND UPPER LEVEL AIRMASS THAT WAS OVER THE AREA
EARLIER TODAY WAS PUSHING OFF TO THE SOUTHWEST. ISOLATED SHOWERS
WILL LIKELY AFFECT AT LEAST KUTS AND KCLL THROUGH ABOUT 02Z OR SO.
THESE MAY DEVELOP A BIT FURTHER TO THE SOUTH AND WILL AMEND IF
NECESSARY. OTHER STORMS OVER WESTERN LA SHOULD DISSIPATE AFTER
SUNSET.
ALTHOUGH THERE MAY BE ANOTHER ISOLATED EPISODE OF A SITE
EXPERIENCING IFR OR LOWER LATE TONIGHT OR EARLY FRIDAY MORNING...
EXPECT MOST LOCATIONS TO REMAIN VFR THROUGH THE NIGHT AND ON
FRIDAY. WENT WITH MVFR FOR KUTS AND KCXO BUT THESE CONDITIONS
COULD ALSO AFFECT KLBX AS WELL. FOR THE MOST PART...FELT THAT AS
THE UPPER LOW MOVES WESTWARD THAT SE TX SHOULD BE IN THE
RELATIVELY DRIER SIDE OF THE SYSTEM THROUGH MIDDAY. THE EXCEPTIONS
SHOULD BE THOSE LOCATIONS NEAR AND ALONG THE COAST IF ISOLATED
SHOWERS DEVELOP OFF THE COAST AND MOVE INLAND DURING THE MORNING.
THE NAM12 WAS MORE AGGRESSIVE TOMORROW AFTERNOON AND FELT THAT
THE CHANCES WERE HIGH ENOUGH GIVEN THAT ANY MOISTURE WRAPPING
AROUND THE UPPER LOW SHOULD HELP ENHANCE THE SEABREEZE OR THE LIFT
PROVIDED BY THE UPPER LEVEL SYSTEM. FOR NOW WILL END THE RAIN
CHANCES NEAR THE COAST AND GO WITH A VCSH DURING THE LATTER HALF
OF THE AFTERNOON FOR MOST INLAND SITES NEAR THE METRO HOUSTON
AIRPORTS.
40
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 74 93 72 94 73 / 20 20 20 30 10
HOUSTON (IAH) 75 93 73 93 73 / 20 30 20 30 20
GALVESTON (GLS) 79 90 79 89 78 / 20 30 20 30 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...43
AVIATION/MARINE...40
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1011 PM CDT SAT JUL 20 2013
UPDATED AVIATION PORTION FOR 06Z 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 06Z TAF ISSUANCE
ISSUED AT 1011 PM CDT SAT JUL 20 2013
MID LEVEL VFR CLOUDS WILL CONTINUE TO PASS OVER THE
AREA TONIGHT INTO SUNDAY ALONG AND NEAR STATIONARY FRONTAL
BOUNDARY. PATCHY MVFR CIGS WITH LIGHT RAIN MAY DEVELOP OVER
CENTRAL WISCONSIN OVERNIGHT AND THEN LATER SUNDAY OVER THE REST OF
THE AREA.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......JKL
AVIATION.......TDH
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
507 PM CDT FRI JUL 19 2013
UPDATED AVIATION PORTION FOR 00Z 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 00Z TAF ISSUANCE
ISSUED AT 507 PM CDT FRI JUL 19 2013
A COLD FRONT WILL CONTINUE TO SLIDE SOUTH OVER THE
SOUTHEAST HALF OF WISCONSIN THIS EVENING. ISOLATED SHOWERS OR
STORMS WILL LINGER THROUGH EARLY EVENING OVER EAST CENTRAL
WISCONSIN. COOLER AND DRIER AIR WILL FILTER INTO THE REGION ON
NORTHWEST WINDS GUSTING TO 20 KNOTS EARLY THIS EVENING. OTHERWISE
VFR CONDITIONS EXPECTED TONIGHT INTO SATURDAY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......TE
AVIATION.......TDH
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
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...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR WIZ046-047-051-052-
056>060-062>072.
LM...SMALL CRAFT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR LMZ643>646.
&&
$$
TONIGHT/SATURDAY AND AVIATION/MARINE...WOOD
SATURDAY NIGHT THROUGH FRIDAY...GEHRING
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST 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 18Z TAF ISSUANCE
ISSUED AT 1233 PM CDT FRI JUL 19 2013
A COLD FRONT WILL DROP SOUTHEAST ACROSS CENTRAL AND
NORTHEAST WISCONSIN THIS AFTERNOON. STORMS HAVE FIRED ALONG THE
FRONT OVER FAR NORTHERN WISCONSIN AND THE UPPER PENINSULA BUT MIXING
OF DRIER AIR TO THE SURFACE HAS LIMITED THE STORMS INTENSITY.
ADDITIONAL STORMS ARE EXPECTED TO FIRE THIS AFTERNOON AND SOME COULD
PRODUCE STRONG GUSTY WINDS. CLEARING IS EXPECTED BEHIND THE COLD
FRONT THIS EVENING WITH GOOD FLYING WEATHER TONIGHT THROUGH SATURDAY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......TE
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1203 PM CDT FRI JUL 19 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 321 AM CDT FRI JUL 19 2013
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED UPPER RIDGING OVER THE WESTERN U.S. AS WELL AS OVER THE
MID-ATLANTIC...WHILE TROUGHING WAS IN-BETWEEN FROM SOUTH CENTRAL
CANADA INTO WESTERN MN. THIS TROUGHING IS COMPOSED OF A POTENT
SHORTWAVE OVER MANITOBA...A SHORTWAVE FROM CENTRAL NORTH DAKOTA INTO
NORTHERN MN...AND A DEEP DRY-SLOT AHEAD OF THE SHORTWAVE FROM SOUTH
DAKOTA INTO WESTERN LAKE SUPERIOR. A COLD FRONT AT THE SURFACE WAS
ANALYZED FROM NEAR SIOUX FALLS TO THUNDER BAY ONTARIO...SLIGHTLY
AHEAD OF THE DRY SLOT. AMAZINGLY...DESPITE 4000 J/KG OF SBCAPE AND
LITTLE CIN ON THE 00Z ABR SOUNDING...THE FRONT WENT THROUGH THERE
WITH LITTLE ACTIVITY. BEST GUESS WAS THE LACK OF CONVERGENCE ON THE
FRONT...WHICH WAS REPRESENTED WELL ON 0-2KM RAP CONVERGENCE PLOTS.
FRONT IS MORE ACTIVE NOW...MORESO THE WARM ADVECTION AHEAD OF
IT...WITH HIGHER BASED SHOWERS AND THUNDERSTORMS FROM FARMINGTON MN
TO PARK FALLS WI. WARM AIR CONTINUES TO HOLD STRONG IN THE WARM
SECTOR WITH READINGS IN THE UPPER 70S / LOW 80S...THANKS IN PART TO
A 30-45 KT 925MB WINDS OVER THE AREA. THERE IS EVEN WARMER AIR
FLOWING IN FROM THE WEST ALONG THE FRONT...OBSERVED ON THE 00Z ABR
SOUNDING WITH AN 800MB TEMP OF 20C AND 925MB TEMP OF 30C...COMPARED
TO 17C AND 27C RESPECTIVELY FROM THE 00Z MPX SOUNDING. BEHIND THE
FRONT...925MB TEMPS ARE NOT THAT MUCH COOLER WITH 28C OBSERVED AT
GGW...BUT DEWPOINTS DROP INTO THE 50S AND LOW 60S.
SYNOPTIC OVERVIEW...
UPPER TROUGHING IS STILL POISED TO FORM OVER THE WESTERN GREAT LAKES
REGION BY 06Z TONIGHT...THOUGH THE MORE POTENT SHORTWAVE COMPOSING
THE TROUGH IS FORECAST TO STAY UP IN CANADA. MEANWHILE...THE
SHORTWAVE SEEN UP IN CENTRAL NORTH DAKOTA IS SLATED TO DROP INTO
CENTRAL MN BY 18Z...THEN PUSH EAST INTO LOWER MI. WITH THE UPPER
TROUGHING FORMING...EXPECT THE COLD FRONT TO CONTINUE MARCHING
SOUTHEAST. MODEL TIMING IS WELL AGREED UPON...AT 18Z STRETCHING FROM
OMAHA NEB TO VOLK FIELD WI AND MARINETTE WI...AND AT 00Z FROM
NORTHWEST MO TO NEAR DUBUQUE IA AND UP TO MANITOWOC WI.
HAZARDS...
ONGOING HEAT ADVISORY...DUE TO FRONTAL TIMING AND DRYING DEWPOINTS
BEHIND THE FRONT...HAVE CANCELLED SOME OF THE ADVISORY. AREAS
INCLUDE SOUTHEAST MN AND PORTIONS OF NORTHEAST IOWA INTO CENTRAL WI.
THERE ALSO IS A CHANCE FOR SEVERE WEATHER THIS AFTERNOON ALONG THE
COLD FRONT COMING THROUGH NORTHEAST IOWA AND SOUTHWEST WI. 0-6KM
SHEAR VALUES ARE HIGHER IN THE 09.00Z NAM...ORDER OF 30-40 KT VERSUS
20-30 KT IN THE 09.06Z RAP. IF SEVERE WEATHER OCCURS...DAMAGING
WINDS WOULD BE THE MAIN HAZARDS.
TODAY...
TWO BIG QUESTIONS...TEMPERATURES AND PRECIPITATION CHANCES. ON THE
PRECIPITATION SIDE OF THINGS...19.00Z GFS/NAM/REGIONAL CANADIAN ALL
WANT TO BRING THE SHOWERS AND SOME THUNDERSTORMS THROUGH THE
FORECAST AREA THIS MORNING PRIOR TO THE FRONTAL PASSAGE. THESE
ORIGINATE FROM ISENTROPIC LIFT ON THE 310 K SURFACE AHEAD OF THE
FRONT. IT APPEARS THESE SHOULD WEAKEN THROUGH THE MORNING TOO WITH
THE NOCTURNAL LOW LEVEL JET WEAKENING. A PERIOD OF CLEARING THEN
TAKES PLACE IN THE WARM SECTOR...WITH SOME HINTS FROM THE 19.00Z
GFS/REGIONAL CANADIAN AND 19.06Z RAP THAT THE FRONT COULD CONVECT IN
SOUTHEASTERN PORTION OF THE FORECAST AREA SAY BETWEEN 19-23Z. NOT
THRILLED ABOUT THE FRONT CONVECTING AS THE 0-2KM CONVERGENCE IS VERY
WEAK. HOWEVER...GIVEN MODELS HAVE BEEN SHOWING IT THE PAST FEW DAYS
AND PLENTY OF INSTABILITY PROGGED TO DEVELOP TODAY...KEPT SOME
CHANCES IN THE FORECAST. HAVE ALSO ADDED SOME LOW CHANCES OF
PRECIPITATION FOR THE AFTERNOON HOURS FROM TAYLOR COUNTY SOUTH TO
JACKSON. HERE ANOTHER FRONT LURKING UP IN NORTHERN MN IS PROGGED BY
THE 09.06Z RAP AND 09.05Z HRRR TO COME THROUGH AND HAVE SOME
CONVECTION ON IT. ON THE TEMPERATURE SIDE OF THINGS...A WARM START
PLUS 925MB TEMPS HOLDING IN THE 24-26C RANGE SHOULD EASILY ALLOWS
HIGHS TO REACH THE UPPER 80S TO POSSIBLY MID 90S AGAIN. THIS IS EVEN
DESPITE THE FRONTAL PASSAGE GIVEN THE WARM AIR STILL HOLDING BACK
AND LIKELY DEEPER MIXING BEHIND THE FRONT. HOWEVER...HEAT INDICES
WILL FALL WITH THE FRONT AS DRIER DEWPOINTS FLOW IN.
TONIGHT...
SUBSIDENCE AND DRYING COMING IN BEHIND THE COLD FRONT WILL ALLOW FOR
A MOSTLY CLEAR NIGHT ACROSS THE FORECAST AREA. DRIER AIR AND
DIMINISHING WINDS SHOULD ALLOW TEMPERATURES TO FALL CLOSE TO
GUIDANCE VALUES...IN THE UPPER 50S TO MID 60S...10-15 DEGREES COLDER
THAN TONIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 321 AM CDT FRI JUL 19 2013
SYNOPTIC OVERVIEW...
MUCH OF THE NEXT 6 DAYS LOOKS TO BE DOMINATED BY NORTHWEST FLOW
ACCORDING TO THE 19.00Z ECMWF/GFS/CANADIAN WITH RIDGING STAYING PUT
OVER THE WESTERN U.S.. THERE ARE SOME SIGNS FROM THE ECMWF THE RIDGE
MAY WANT TO BUILD EAST TOWARDS THE FORECAST AREA ON THURSDAY...BUT
PLENTY OF UNCERTAINTY ON THAT SEEING THE TROUGHING IN THE GFS.
ADDITIONALLY...THIS NORTHWEST FLOW HAS UNCERTAINTY IN TERMS OF
TIMING SHORTWAVES AND THE CHANCES OF PRECIPITATION WITH THEM.
SATURDAY THROUGH SUNDAY NIGHT...
MAIN FEATURE OF INTEREST DURING THIS PERIOD IS A SHORTWAVE ALL
MODELS HAVE TRACKING OUT OF MONTANA ON SATURDAY AND THROUGH THE
FORECAST AREA ON SUNDAY. SURPRISINGLY MODELS ARE IN REALLY GOOD
AGREEMENT WITH THIS SHORTWAVE...ALBEIT PERHAPS THE GFS HAS A BIT OF
CONVECTIVE FEEDBACK TO IT. IN ANY EVENT...INCREASING 310 K
ISENTROPIC LIFT COMBINED WITH INSTABILITY SHOULD INITIATE CONVECTION
OVER EASTERN SOUTH DAKOTA DURING THE AFTERNOON. THIS CONVECTION THEN
SPREADS TOWARDS THE FORECAST AREA SATURDAY NIGHT AS THE ISENTROPIC
LIFT AND 850MB MOISTURE TRANSPORT AHEAD OF THE SHORTWAVE SHIFTS
EAST. PERHAPS THERE IS A SHOT SOME HIGH BASED SHOWERS COULD DEVELOP
DOWNSTREAM OF THE CONVECTION SATURDAY AFTERNOON...BUT THINK THE BULK
OF THE PRECIPITATION WOULD WAIT UNTIL SATURDAY NIGHT. SUNDAY APPEARS
TO HAVE THE HIGHEST CHANCE OF RAIN WHERE DPVA ACCOMPANYING THE
SHORTWAVE INTERSECTS 850MB MOISTURE TRANSPORT CONTINUING TO AIM AT
THE AREA. ITS HARD TO SAY HOW SUNDAY NIGHT WILL EVOLVE. SUBSIDENCE
BEHIND THE SHORTWAVE MOVING THROUGH ON SUNDAY WOULD SEEM TO LIKELY
PROVIDE A DRY PERIOD...LIKE SUGGESTED BY THE 19.00Z NAM. HOWEVER...
THE 19.00Z GFS/ECMWF SHOW A POTENT SHORTWAVE TROUGH CROSSING
SOUTHERN MANITOBA SUNDAY NIGHT...WHICH INCREASES 850MB MOISTURE
TRANSPORT INTO THE AREA. THEREFORE...THESE MODELS WANT TO HANG ONTO
SOME SHOWERS. HAVE MAINTAINED SOME CHANCES OF PRECIPITATION TO
ACCOUNT FOR THE GFS/ECMWF SCENARIO. BIGGEST ISSUE IN THE TEMPERATURE
DEPARTMENT IS HIGHS ON SUNDAY. IF IT RAINS ALL DAY...TEMPERATURES
MAY GET STUCK IN THE UPPER 60S/LOW 70S. FOR NOW TRENDED HIGHS DOWN
SLIGHTLY.
MONDAY THROUGH THURSDAY NIGHT...
THIS PERIOD IS HIGHLY UNCERTAIN. 19.00Z GFS/ECMWF/CANADIAN SHOW
NUMEROUS SHORTWAVES MOVING THROUGH THE NORTHWEST FLOW ALOFT THROUGH
MUCH OF THE WEEK. TIMING AND TRACK OF THESE VARIES FROM RUN TO
RUN...THUS THE LOW CONFIDENCE. THERE DOES APPEAR TO BE SOME SIGNAL
FOR A COLD FRONT COMING THROUGH THE FORECAST AREA MONDAY
NIGHT...ASSOCIATED WITH THAT POTENT TROUGH OVER SOUTHERN MANITOBA
PROGGED TO LIFT EAST-NORTHEAST. IF THIS STAYS CONSISENT...WE MIGHT
BE ABLE TO DRY OUT TUESDAY. OTHERWISE...HAVE MAINTAINED A MODEL
CONSENSUS OF 20-40 PERCENT CHANCES THROUGH THURSDAY NIGHT. LIKELY
THE ENTIRE PERIOD WILL NOT BE WET...BUT HARD TO PIN POINT MUCH FOR
POSSIBLE DRY PERIODS BEYOND TUESDAY. WITH A NORTHWEST FLOW IN
PLACE...EXPECT A COOLER FLOW OF AIR. 850MB TEMPS ARE GENERALLY
PROGGED TO DROP FROM 18-20C ON MONDAY TO 12-15C FOR TUESDAY THROUGH
THURSDAY. THESE SHOULD RESULT IN A DROP IN HIGHS TO SLIGHTLY BELOW
NORMAL AFTER NEAR NORMAL ON MONDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1203 PM CDT FRI JUL 19 2013
COLD FRONT MAKING STEADY SOUTHEASTWARD PROGRESS THROUGH THE AREA.
IT HAS ALREADY PASSED THROUGH KRST AND SHOULD BE THROUGH KLSE BY
OR JUST AFTER 18Z. WILL THUS START BOTH SITES WITH SOME GUSTY
NORTHWEST WINDS. THE WINDS EXPECTED TO DIE DOWN EARLY IN THE
EVENING AS HIGH PRESSURE BUILDS IN FROM THE NORTHWEST RELAXING THE
GRADIENT. NOT EXPECTING ANY FOG TO FORM OVERNIGHT AT KLSE AS THE
NORTHWEST WINDS WILL BRING IN DRIER AIR WITH DEW POINTS EXPECTED
TO DROP INTO THE LOWER 60S MAINTAINING A TEMP/DEW POINT SPREAD OF
AT LEAST 4 DEGREES THROUGH THE NIGHT.
&&
.CLIMATE...
ISSUED AT 321 AM CDT FRI JUL 19 2013
LA CROSSE WI HAS ONLY SEEN 0.27 INCHES FOR THE MONTH OF JULY
THROUGH THE 18TH. THIS IS THE 5TH DRIEST START TO JULY. THE DRIEST
THROUGH JULY 18TH WAS 0.05 INCHES BACK IN 1896...AND THE LAST TIME
IT WAS THIS DRY WAS IN 1967. FOR REFERENCE...LA CROSSE NORMALLY
SHOULD HAVE 2.41 INCHES UP THROUGH THE 18TH.
ROCHESTER MN HAS HAD QUITE A BIT MORE RAIN...THUS THE 1.42 INCHES
OBSERVED THROUGH JULY 18TH IS WELL OUTSIDE THE TOP 20 DRIEST.
STILL ROCHESTER IS 1.25 INCHES BELOW NORMAL.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR WIZ041>044-053>055-
061.
MN...NONE.
IA...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR IAZ011-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...04
CLIMATE...AJ
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1051 AM CDT FRI JUL 19 2013
.UPDATE...THE LINE OF SHOWERS AND THUNDERSTORMS THAT WERE MOVING
THROUGH WEST CENTRAL AND CENTRAL WI...AND SOUTHEAST MN EARLIER
THIS MORNING HAVE ALL BUT DISSIPATED UPON MOVING SOUTHEAST INTO
THE CWA AS OF 10 AM CDT. VIS SAT SHOWS CONVECTIVE DEBRIS AND MID
LEVEL ACCAS ORIENTED SW TO NE MOVING SOUTHEAST THROUGH SOUTH
CENTRAL AND EAST CENTRAL WISCONSIN. UPSTREAM...DIURNAL CU ALREADY
DEVELOPING IN GRB AND MSP FORECAST AREAS.
MAIN CHANGES WERE LIMITED TO CURRENT TRENDS AND UPDATING THE
WX/POPS IN THE TODAY PERIOD. HIGHS LOOK ON TRACK AS IS. REGARDING
POPS/WX THIS AFTERNOON/EVENING...ECMWF AND NAM NOT PRODUCING MUCH
QPF WITH FROPA. HRRR AND LOCAL WRF FLAVOR PRODUCING ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS WITH FROPA...BUT NOT LARGE
IN COVERAGE. ACTIVITY IS MAINLY SHOWN TO DEVELOP AFTER 20
UTC...WITH THE BULK OF THE ACTIVITY THE SOUTHEAST HALF OF THE CWA.
DESTABILIZATION SHOULD BE SUFFICIENT TODAY GIVEN CURRENT
CONDITIONS AND AFTER THESE CLOUDS MOVE THROUGH.
LOOKING AT THE NEAR STORM ENVIRONMENT THIS AFTERNOON AND EVENING
FROM THE RAP...DEEP LAYERED 0-6 KM SHEAR PEAKS AROUND 30-35
KTS...AMPLE ML CAPE INSTABILITY IS PRESENT...AND LOW-LEVEL
MOISTURE WILL BE FAVORABLE WITH SFC DEW POINTS IN THE LOW 70S. AS
SUCH...THE ENVIRONMENT STILL LOOKS SUPPORTIVE FOR MULTICELLS AND A
FEW SUPERCELLS PROVIDED THINGS GET UNDERWAY. SPC SSEO DOESNT
SHOW MUCH POTENTIAL IN REGARD TO SUPERCELLS THOUGH. ESPECIALLY
WHEN LOOKING AT THE UPDRAFT HELICITY IN TERMS OF A SIGNAL THIS
AFTERNOON/EVENING.
ET
&&
.AVIATION/18Z TAFS/...VFR CONDITIONS ARE EXPECTED ACROSS TAF SITES
THIS AFTERNOON...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 THIS AFTERNOON IN
THE WAKE OF THE MID LEVEL CLOUDS NOW MOVING THROUGH 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.
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 SOUTHWEST
THROUGH THE AREA. MOSTLY CLEAR SKIES ARE EXPECTED SATURDAY.
WOOD
&&
.MARINE...SMALL CRAFT ADVISORY CONTINUES UNTIL 00Z SATURDAY FOR
ALL OF THE NEARSHORE WATERS. TIGHT PRESSURE GRADIENT AND DAYTIME
HEATING ALLOWING FOR GUSTY SOUTHWEST TO WEST WINDS ACROSS THE
WATERS. THESE WINDS WILL CONTINUE THROUGH THE REST OF THE
DAY...THUS HAVE EXTENDED SMALL CRAFT ADVISORY NORTH OF NORTH POINT
LIGHTHOUSE UNTIL 00Z SATURDAY. WAVES WILL REMAIN WELL BELOW SMALL
CRAFT ADVISORY CRITERIA WITH OFFSHORE FLOW. WINDS WILL THEN
SUBSIDE EARLY THIS EVENING WITH WEAKENING PRESSURE GRADIENT AND
PASSING COLD FRONT.
WOOD
&&
.PREV DISCUSSION... /ISSUED 338 AM CDT FRI JUL 19 2013/
SHORT TERM...
TODAY AND TONIGHT...FORECAST CONFIDENCE...MEDIUM
CURRENTLY WATCHING A LINE OF PRE-FRONTAL THUNDERSTORMS FROM
NORTHWEST WISCONSIN THROUGH SOUTH-CENTRAL MINNESOTA. SEEMS THESE
STORMS ARE HOLDING UP FAIRLY WELL RIGHT NOW...SO INCREASED MORNING
POPS A BIT IN THE NORTHWEST HALF OF THE FORECAST AREA. KIND OF A
TRICKY ONE THOUGH...BECAUSE MODELS ARE ALL DOING DIFFERENT THINGS
WITH THIS MORNING CONVECTION...FROM WIPING IT OUT BEFORE IT
ARRIVES...TO PUSHING IT ALL THE WAY THROUGH THE FORECAST AREA. THE
AMOUNT OF CLOUDS/PRECIP ACROSS SRN WI THIS MORNING WILL CERTAINLY
IMPACT HIGH TEMPS AND RESULTANT DESTABILIZATION FOR THE NEXT ROUND
OF STORMS AS THE COLD FRONT APPROACHES.
WENT WITH THE SOLUTION SEEN IN THE MOST MODELS...WHICH WOULD BRINGS
THE LINE OF STORMS IN...BUT WIPES IT OUT BY THE TIME IT REACHES THE
SOUTHEAST. THIS WOULD LEAVE A WINDOW OF OPPORTUNITY TO HEAT BACK UP
AHEAD OF THE FRONT. GIVEN SUFFICIENT SUNSHINE...MODELS SUGGEST
SURFACE BASED CAPES REACHING AROUND 3000 J/KG THIS AFTERNOON.
ALSO...0-6 KM BULK SHEAR WILL BE 30-35 KT. THE BEST 850 FLOW WILL BE
SET UP JUST TO THE SOUTH AND INTO MICHIGAN...ALONG WITH THE BETTER
UPPER DIVERGENCE. STILL...SEEMS LIKE A DECENT SETUP FOR STRONG TO
SEVERE STORMS IF THEY CAN GET GOING THIS AFTERNOON. THE NAM DOES
SHOW A BIT OF A CAP THROUGH MUCH OF THE AFTERNOON WHICH COULD BE AN
ISSUE. WENT WITH HIGH CHANCE POPS FOR THROUGH THE DAY DUE TO GENERAL
UNCERTAINTY. MAY NEED TO RAISE MORNING POPS IN AT LEAST THE
NORTHWEST THOUGH IF THE CONVECTION TO THE NORTHWEST CONTINUES TO
HOLD TOGETHER.
LOOKS LIKE ANOTHER HOT AND HUMID ONE TODAY AHEAD OF THE FRONT. GIVEN
MORNING CLOUDS AND CONVECTION AND THEN POSSIBLE REDEVELOPMENT THIS
AFTERNOON...WENT WITH HIGHS A COUPLE DEGREES LOWER THAN THE LAST
COUPLE DAYS. STILL LOOKS LIKE 95-100 DEGREE HEAT INDICIES
THOUGH...POSSIBLY A BIT OVER 100 IN A FEW SPOTS. WILL THUS KEEP HEAT
ADVISORY GOING INTO EARLY EVENING.
SHOULD TURN DRY BY LATE EVENING AS THE FRONT PUSHES THROUGH. SHOULD
SEE LOWS ACTUALLY FALL INTO THE 60S MOST PLACES OVERNIGHT AS COOLER
AND DRIER AIR BEGINS TO MOVE IN BEHIND THE FRONT.
SATURDAY...FORECAST CONFIDENCE HIGH.
A SECONDARY COLD FRONT WILL DROP DOWN THROUGH WI ON SATURDAY...WITH
WINDS BECOMING NORTH. THE MODELS SHOW THE FRONT ACCELERATING DOWN
THE LAKE A LITTLE FASTER THAN ON LAND AND PRODUCE LIGHT QPF ALONG
THE CONVERGENCE LINE IN SOUTHEAST WI. WILL CONTINUE DRY FORECAST FOR
NOW GIVEN THE WEAK FORCING.
WITH MORNING SUNSHINE AND THE COLD FRONT WEAKENING AS IT GETS INTO
SOUTH CENTRAL WI...HIGHS WILL BE IN THE LOWER 80S OVER MUCH OF THE
AREA. THE COOL SPOT IN THE UPPER 70S WILL BE THE SHEBOYGAN AREA
WHERE NORTH WINDS SHOULD PUSH INLAND EARLIER IN THE DAY. THIS WILL
BE A WELCOMED RELIEF TO THE HEAT WAVE.
SATURDAY NIGHT THROUGH SUNDAY...FORECAST CONFIDENCE MEDIUM.
LATER SATURDAY NIGHT...THE LOW LEVEL JET WILL POINT INTO WESTERN WI
ALONG WITH 850MB WARM AIR ADVECTION AND A SHORTWAVE TROUGH MOVING
ACROSS THE UPPER MIDWEST. THE ELEVATED THUNDERSTORM CHANCE WILL BE
HIGHER TOWARD EASTERN MN/WESTERN WI...BUT ADDED A SMALL CHANCE IN
THE WESTERN MKX FORECAST AREA.
THIS FAVORED AREA FOR THUNDERSTORMS IN THE VICINITY OF THE LOW LEVEL
JET AND THE SHORTWAVE TROUGH WILL SHIFT EASTWARD ACROSS WI THROUGH
THE DAY SUNDAY. THE NAM FOCUSES CONVECTION MORE IN NORTHERN WI ON
THE NOSE OF THE LLJ WHILE THE ECMWF DIMINISHES THAT CONVECTION.
THERE WILL BE ANOTHER AREA OF CONVECTION TIED MORE TOWARD THE BASE
OF THE SHORTWAVE TROUGH OVER IL. THERE IS A CHANCE THAT SOUTHERN WI
WILL END UP BETWEEN THE TWO AREAS OF CONVECTION.
THE ECMWF IS SLOWER WITH THE 500MB TROUGH CROSSING WI...SO CHANCE OF
THUNDERSTORMS CONTINUES THROUGH SUNDAY NIGHT.
EITHER WAY...EXPECT PLENTY OF CLOUDS SUNDAY. ALONG WITH 925MB TEMPS
ONLY AROUND 18C...HIGHS WILL BE IN THE UPPER 70S INLAND AND
LOWER/MID 70S NEAR THE LAKE WITH EAST WINDS.
LONG TERM...
MONDAY THROUGH TUESDAY...FORECAST CONFIDENCE MEDIUM.
A 500MB NORTHWEST FLOW PATTERN SETS UP OVER THE UPPER MIDWEST FOR
THE FIRST HALF OF NEXT WEEK. WEAK SHORTWAVES WILL BRING THUNDERSTORM
CHANCES TO SOUTHERN WI ON MONDAY. THERE IS GENERALLY AGREEMENT
BETWEEN THE GFS AND ECMWF THAT A SURFACE LOW PRESSURE TROUGH WILL
SWEEP SOUTHEAST THROUGH WI MONDAY NIGHT INTO TUE MORNING WITH
THUNDERSTORM CHANCES ALONG THAT FRONT.
WEDNESDAY THROUGH THURSDAY...FORECAST CONFIDENCE MEDIUM TO LOW.
SURFACE HIGH PRESSURE IS EXPECTED OVER THE GREAT LAKES REGION ON
WEDNESDAY. THEN THE GFS BRINGS THUNDERSTORMS INTO SOUTHERN WI ONCE
AGAIN ON ANOTHER SHORTWAVE WHILE THE ECMWF KEEPS US HIGH AND DRY. IT
WILL DEPEND ON HOW AMPLIFIED THAT EASTERN UPPER TROUGH WILL BECOME.
AVIATION/12Z TAFS/...
WILL BE A CHANCE FOR SHOWERS AND STORMS TODAY AS A COLD FRONT MOVES
THROUGH THE FORECAST AREA. WILL PROBABLY SEE TWO ROUNDS...THE FIRST
OF WHICH WILL ARRIVE IN THE NORTHWEST THIS MORNING. SOME UNCERTAINTY
AS TO HOW WELL THIS WILL HOLD TOGETHER AS IT PROGRESSES SOUTHEAST.
SECOND ROUND WILL LIKELY FIRE RIGHT AHEAD OF THE FRONT BY LATE
AFTERNOON...WITH THE BEST CHANCE THEN ACROSS THE SOUTHEAST HALF OF
THE FORECAST AREA. SOME OF THE STORMS COULD BE STRONG TO SEVERE THIS
AFTERNOON INTO EARLY EVENING.
WILL THEN TURN DRY BY LATE EVENING...WITH QUIET WEATHER EXPECTED
OVERNIGHT AND INTO SATURDAY.
VFR CONDITIONS WILL PREVAIL THROUGH THE NEXT 24 HOURS...EXCEPT FOR
LOWER VSBYS POSSIBLE IN ANY MODERATE TO HEAVY RAINFALL.
MARINE...
SOUTHWEST WINDS WILL LIKELY REACH SMALL CRAFT ADVISORY LEVELS TODAY
AHEAD OF AN APPROACHING COLD FRONT. THE BEST CHANCE FOR HIGHER GUSTS
WILL BE ALONG SHORE FROM MID MORNING INTO LATE AFTERNOON NORTH AND
EARLY EVENING SOUTH. A SMALL CRAFT ADVISORY WILL THUS BE ISSUED THIS
MORNING.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR WIZ046-047-051-052-
056>060-062>072.
LM...SMALL CRAFT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR LMZ643>646.
&&
$$
UPDATE...ET/WOOD
TODAY/TONIGHT AND AVIATION/MARINE...DDV
SATURDAY THROUGH THURSDAY...MRC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
625 AM CDT FRI JUL 19 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 321 AM CDT FRI JUL 19 2013
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED UPPER RIDGING OVER THE WESTERN U.S. AS WELL AS OVER THE
MID-ATLANTIC...WHILE TROUGHING WAS IN-BETWEEN FROM SOUTH CENTRAL
CANADA INTO WESTERN MN. THIS TROUGHING IS COMPOSED OF A POTENT
SHORTWAVE OVER MANITOBA...A SHORTWAVE FROM CENTRAL NORTH DAKOTA INTO
NORTHERN MN...AND A DEEP DRY-SLOT AHEAD OF THE SHORTWAVE FROM SOUTH
DAKOTA INTO WESTERN LAKE SUPERIOR. A COLD FRONT AT THE SURFACE WAS
ANALYZED FROM NEAR SIOUX FALLS TO THUNDER BAY ONTARIO...SLIGHTLY
AHEAD OF THE DRY SLOT. AMAZINGLY...DESPITE 4000 J/KG OF SBCAPE AND
LITTLE CIN ON THE 00Z ABR SOUNDING...THE FRONT WENT THROUGH THERE
WITH LITTLE ACTIVITY. BEST GUESS WAS THE LACK OF CONVERGENCE ON THE
FRONT...WHICH WAS REPRESENTED WELL ON 0-2KM RAP CONVERGENCE PLOTS.
FRONT IS MORE ACTIVE NOW...MORESO THE WARM ADVECTION AHEAD OF
IT...WITH HIGHER BASED SHOWERS AND THUNDERSTORMS FROM FARMINGTON MN
TO PARK FALLS WI. WARM AIR CONTINUES TO HOLD STRONG IN THE WARM
SECTOR WITH READINGS IN THE UPPER 70S / LOW 80S...THANKS IN PART TO
A 30-45 KT 925MB WINDS OVER THE AREA. THERE IS EVEN WARMER AIR
FLOWING IN FROM THE WEST ALONG THE FRONT...OBSERVED ON THE 00Z ABR
SOUNDING WITH AN 800MB TEMP OF 20C AND 925MB TEMP OF 30C...COMPARED
TO 17C AND 27C RESPECTIVELY FROM THE 00Z MPX SOUNDING. BEHIND THE
FRONT...925MB TEMPS ARE NOT THAT MUCH COOLER WITH 28C OBSERVED AT
GGW...BUT DEWPOINTS DROP INTO THE 50S AND LOW 60S.
SYNOPTIC OVERVIEW...
UPPER TROUGHING IS STILL POISED TO FORM OVER THE WESTERN GREAT LAKES
REGION BY 06Z TONIGHT...THOUGH THE MORE POTENT SHORTWAVE COMPOSING
THE TROUGH IS FORECAST TO STAY UP IN CANADA. MEANWHILE...THE
SHORTWAVE SEEN UP IN CENTRAL NORTH DAKOTA IS SLATED TO DROP INTO
CENTRAL MN BY 18Z...THEN PUSH EAST INTO LOWER MI. WITH THE UPPER
TROUGHING FORMING...EXPECT THE COLD FRONT TO CONTINUE MARCHING
SOUTHEAST. MODEL TIMING IS WELL AGREED UPON...AT 18Z STRETCHING FROM
OMAHA NEB TO VOLK FIELD WI AND MARINETTE WI...AND AT 00Z FROM
NORTHWEST MO TO NEAR DUBUQUE IA AND UP TO MANITOWOC WI.
HAZARDS...
ONGOING HEAT ADVISORY...DUE TO FRONTAL TIMING AND DRYING DEWPOINTS
BEHIND THE FRONT...HAVE CANCELLED SOME OF THE ADVISORY. AREAS
INCLUDE SOUTHEAST MN AND PORTIONS OF NORTHEAST IOWA INTO CENTRAL WI.
THERE ALSO IS A CHANCE FOR SEVERE WEATHER THIS AFTERNOON ALONG THE
COLD FRONT COMING THROUGH NORTHEAST IOWA AND SOUTHWEST WI. 0-6KM
SHEAR VALUES ARE HIGHER IN THE 09.00Z NAM...ORDER OF 30-40 KT VERSUS
20-30 KT IN THE 09.06Z RAP. IF SEVERE WEATHER OCCURS...DAMAGING
WINDS WOULD BE THE MAIN HAZARDS.
TODAY...
TWO BIG QUESTIONS...TEMPERATURES AND PRECIPITATION CHANCES. ON THE
PRECIPITATION SIDE OF THINGS...19.00Z GFS/NAM/REGIONAL CANADIAN ALL
WANT TO BRING THE SHOWERS AND SOME THUNDERSTORMS THROUGH THE
FORECAST AREA THIS MORNING PRIOR TO THE FRONTAL PASSAGE. THESE
ORIGINATE FROM ISENTROPIC LIFT ON THE 310 K SURFACE AHEAD OF THE
FRONT. IT APPEARS THESE SHOULD WEAKEN THROUGH THE MORNING TOO WITH
THE NOCTURNAL LOW LEVEL JET WEAKENING. A PERIOD OF CLEARING THEN
TAKES PLACE IN THE WARM SECTOR...WITH SOME HINTS FROM THE 19.00Z
GFS/REGIONAL CANADIAN AND 19.06Z RAP THAT THE FRONT COULD CONVECT IN
SOUTHEASTERN PORTION OF THE FORECAST AREA SAY BETWEEN 19-23Z. NOT
THRILLED ABOUT THE FRONT CONVECTING AS THE 0-2KM CONVERGENCE IS VERY
WEAK. HOWEVER...GIVEN MODELS HAVE BEEN SHOWING IT THE PAST FEW DAYS
AND PLENTY OF INSTABILITY PROGGED TO DEVELOP TODAY...KEPT SOME
CHANCES IN THE FORECAST. HAVE ALSO ADDED SOME LOW CHANCES OF
PRECIPITATION FOR THE AFTERNOON HOURS FROM TAYLOR COUNTY SOUTH TO
JACKSON. HERE ANOTHER FRONT LURKING UP IN NORTHERN MN IS PROGGED BY
THE 09.06Z RAP AND 09.05Z HRRR TO COME THROUGH AND HAVE SOME
CONVECTION ON IT. ON THE TEMPERATURE SIDE OF THINGS...A WARM START
PLUS 925MB TEMPS HOLDING IN THE 24-26C RANGE SHOULD EASILY ALLOWS
HIGHS TO REACH THE UPPER 80S TO POSSIBLY MID 90S AGAIN. THIS IS EVEN
DESPITE THE FRONTAL PASSAGE GIVEN THE WARM AIR STILL HOLDING BACK
AND LIKELY DEEPER MIXING BEHIND THE FRONT. HOWEVER...HEAT INDICES
WILL FALL WITH THE FRONT AS DRIER DEWPOINTS FLOW IN.
TONIGHT...
SUBSIDENCE AND DRYING COMING IN BEHIND THE COLD FRONT WILL ALLOW FOR
A MOSTLY CLEAR NIGHT ACROSS THE FORECAST AREA. DRIER AIR AND
DIMINISHING WINDS SHOULD ALLOW TEMPERATURES TO FALL CLOSE TO
GUIDANCE VALUES...IN THE UPPER 50S TO MID 60S...10-15 DEGREES COLDER
THAN TONIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 321 AM CDT FRI JUL 19 2013
SYNOPTIC OVERVIEW...
MUCH OF THE NEXT 6 DAYS LOOKS TO BE DOMINATED BY NORTHWEST FLOW
ACCORDING TO THE 19.00Z ECMWF/GFS/CANADIAN WITH RIDGING STAYING PUT
OVER THE WESTERN U.S.. THERE ARE SOME SIGNS FROM THE ECMWF THE RIDGE
MAY WANT TO BUILD EAST TOWARDS THE FORECAST AREA ON THURSDAY...BUT
PLENTY OF UNCERTAINTY ON THAT SEEING THE TROUGHING IN THE GFS.
ADDITIONALLY...THIS NORTHWEST FLOW HAS UNCERTAINTY IN TERMS OF
TIMING SHORTWAVES AND THE CHANCES OF PRECIPITATION WITH THEM.
SATURDAY THROUGH SUNDAY NIGHT...
MAIN FEATURE OF INTEREST DURING THIS PERIOD IS A SHORTWAVE ALL
MODELS HAVE TRACKING OUT OF MONTANA ON SATURDAY AND THROUGH THE
FORECAST AREA ON SUNDAY. SURPRISINGLY MODELS ARE IN REALLY GOOD
AGREEMENT WITH THIS SHORTWAVE...ALBEIT PERHAPS THE GFS HAS A BIT OF
CONVECTIVE FEEDBACK TO IT. IN ANY EVENT...INCREASING 310 K
ISENTROPIC LIFT COMBINED WITH INSTABILITY SHOULD INITIATE CONVECTION
OVER EASTERN SOUTH DAKOTA DURING THE AFTERNOON. THIS CONVECTION THEN
SPREADS TOWARDS THE FORECAST AREA SATURDAY NIGHT AS THE ISENTROPIC
LIFT AND 850MB MOISTURE TRANSPORT AHEAD OF THE SHORTWAVE SHIFTS
EAST. PERHAPS THERE IS A SHOT SOME HIGH BASED SHOWERS COULD DEVELOP
DOWNSTREAM OF THE CONVECTION SATURDAY AFTERNOON...BUT THINK THE BULK
OF THE PRECIPITATION WOULD WAIT UNTIL SATURDAY NIGHT. SUNDAY APPEARS
TO HAVE THE HIGHEST CHANCE OF RAIN WHERE DPVA ACCOMPANYING THE
SHORTWAVE INTERSECTS 850MB MOISTURE TRANSPORT CONTINUING TO AIM AT
THE AREA. ITS HARD TO SAY HOW SUNDAY NIGHT WILL EVOLVE. SUBSIDENCE
BEHIND THE SHORTWAVE MOVING THROUGH ON SUNDAY WOULD SEEM TO LIKELY
PROVIDE A DRY PERIOD...LIKE SUGGESTED BY THE 19.00Z NAM. HOWEVER...
THE 19.00Z GFS/ECMWF SHOW A POTENT SHORTWAVE TROUGH CROSSING
SOUTHERN MANITOBA SUNDAY NIGHT...WHICH INCREASES 850MB MOISTURE
TRANSPORT INTO THE AREA. THEREFORE...THESE MODELS WANT TO HANG ONTO
SOME SHOWERS. HAVE MAINTAINED SOME CHANCES OF PRECIPITATION TO
ACCOUNT FOR THE GFS/ECMWF SCENARIO. BIGGEST ISSUE IN THE TEMPERATURE
DEPARTMENT IS HIGHS ON SUNDAY. IF IT RAINS ALL DAY...TEMPERATURES
MAY GET STUCK IN THE UPPER 60S/LOW 70S. FOR NOW TRENDED HIGHS DOWN
SLIGHTLY.
MONDAY THROUGH THURSDAY NIGHT...
THIS PERIOD IS HIGHLY UNCERTAIN. 19.00Z GFS/ECMWF/CANADIAN SHOW
NUMEROUS SHORTWAVES MOVING THROUGH THE NORTHWEST FLOW ALOFT THROUGH
MUCH OF THE WEEK. TIMING AND TRACK OF THESE VARIES FROM RUN TO
RUN...THUS THE LOW CONFIDENCE. THERE DOES APPEAR TO BE SOME SIGNAL
FOR A COLD FRONT COMING THROUGH THE FORECAST AREA MONDAY
NIGHT...ASSOCIATED WITH THAT POTENT TROUGH OVER SOUTHERN MANITOBA
PROGGED TO LIFT EAST-NORTHEAST. IF THIS STAYS CONSISENT...WE MIGHT
BE ABLE TO DRY OUT TUESDAY. OTHERWISE...HAVE MAINTAINED A MODEL
CONSENSUS OF 20-40 PERCENT CHANCES THROUGH THURSDAY NIGHT. LIKELY
THE ENTIRE PERIOD WILL NOT BE WET...BUT HARD TO PIN POINT MUCH FOR
POSSIBLE DRY PERIODS BEYOND TUESDAY. WITH A NORTHWEST FLOW IN
PLACE...EXPECT A COOLER FLOW OF AIR. 850MB TEMPS ARE GENERALLY
PROGGED TO DROP FROM 18-20C ON MONDAY TO 12-15C FOR TUESDAY THROUGH
THURSDAY. THESE SHOULD RESULT IN A DROP IN HIGHS TO SLIGHTLY BELOW
NORMAL AFTER NEAR NORMAL ON MONDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 625 AM CDT FRI JUL 19 2013
A COLD FRONT WILL DRIFT SOUTHEAST ACROSS THE AREA TODAY BRINGING
SCATTERED SHOWERS AND THUNDERSTORMS TO THE TAF SITES EARLY. THE
FRONT IS EXPECTED TO PUSH SOUTH OF THE TAF SITES BY EARLY THIS
AFTERNOON WITH WINDS SWITCHING TO THE NORTHWEST AND INCREASING TO
15 TO 18 KTS WITH GUSTS TO AROUND 25 KTS POSSIBLE. SOME OF THE
STORMS MAY PRODUCE BRIEF HEAVY DOWNPOURS AND GUSTY WINDS TO 45 KTS
THIS MORNING. WILL HAVE TO KEEP A VERY CLOSE WATCH FOR STORMS
REDEVELOPING ALONG THE FRONT LATE THIS MORNING INTO THIS
AFTERNOON. A FEW OF THESE STORMS COULD BECOME SEVERE WITH DAMAGING
WINDS. HIGH PRESSURE WILL BUILD INTO THE REGION TONIGHT PROVIDING
VFR CONDITIONS. SOME PATCHY FOG IS POSSIBLE TONIGHT...ESPECIALLY IN
VALLEY LOCATIONS.
&&
.CLIMATE...
ISSUED AT 321 AM CDT FRI JUL 19 2013
LA CROSSE WI HAS ONLY SEEN 0.27 INCHES FOR THE MONTH OF JULY
THROUGH THE 18TH. THIS IS THE 5TH DRIEST START TO JULY. THE DRIEST
THROUGH JULY 18TH WAS 0.05 INCHES BACK IN 1896...AND THE LAST TIME
IT WAS THIS DRY WAS IN 1967. FOR REFERENCE...LA CROSSE NORMALLY
SHOULD HAVE 2.41 INCHES UP THROUGH THE 18TH.
ROCHESTER MN HAS HAD QUITE A BIT MORE RAIN...THUS THE 1.42 INCHES
OBSERVED THROUGH JULY 18TH IS WELL OUTSIDE THE TOP 20 DRIEST.
STILL ROCHESTER IS 1.25 INCHES BELOW NORMAL.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR WIZ041>044-053>055-
061.
MN...NONE.
IA...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR IAZ011-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...WETENKAMP
CLIMATE...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
321 AM CDT FRI JUL 19 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 321 AM CDT FRI JUL 19 2013
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED UPPER RIDGING OVER THE WESTERN U.S. AS WELL AS OVER THE
MID-ATLANTIC...WHILE TROUGHING WAS IN-BETWEEN FROM SOUTH CENTRAL
CANADA INTO WESTERN MN. THIS TROUGHING IS COMPOSED OF A POTENT
SHORTWAVE OVER MANITOBA...A SHORTWAVE FROM CENTRAL NORTH DAKOTA INTO
NORTHERN MN...AND A DEEP DRY-SLOT AHEAD OF THE SHORTWAVE FROM SOUTH
DAKOTA INTO WESTERN LAKE SUPERIOR. A COLD FRONT AT THE SURFACE WAS
ANALYZED FROM NEAR SIOUX FALLS TO THUNDER BAY ONTARIO...SLIGHTLY
AHEAD OF THE DRY SLOT. AMAZINGLY...DESPITE 4000 J/KG OF SBCAPE AND
LITTLE CIN ON THE 00Z ABR SOUNDING...THE FRONT WENT THROUGH THERE
WITH LITTLE ACTIVITY. BEST GUESS WAS THE LACK OF CONVERGENCE ON THE
FRONT...WHICH WAS REPRESENTED WELL ON 0-2KM RAP CONVERGENCE PLOTS.
FRONT IS MORE ACTIVE NOW...MORESO THE WARM ADVECTION AHEAD OF
IT...WITH HIGHER BASED SHOWERS AND THUNDERSTORMS FROM FARMINGTON MN
TO PARK FALLS WI. WARM AIR CONTINUES TO HOLD STRONG IN THE WARM
SECTOR WITH READINGS IN THE UPPER 70S / LOW 80S...THANKS IN PART TO
A 30-45 KT 925MB WINDS OVER THE AREA. THERE IS EVEN WARMER AIR
FLOWING IN FROM THE WEST ALONG THE FRONT...OBSERVED ON THE 00Z ABR
SOUNDING WITH AN 800MB TEMP OF 20C AND 925MB TEMP OF 30C...COMPARED
TO 17C AND 27C RESPECTIVELY FROM THE 00Z MPX SOUNDING. BEHIND THE
FRONT...925MB TEMPS ARE NOT THAT MUCH COOLER WITH 28C OBSERVED AT
GGW...BUT DEWPOINTS DROP INTO THE 50S AND LOW 60S.
SYNOPTIC OVERVIEW...
UPPER TROUGHING IS STILL POISED TO FORM OVER THE WESTERN GREAT LAKES
REGION BY 06Z TONIGHT...THOUGH THE MORE POTENT SHORTWAVE COMPOSING
THE TROUGH IS FORECAST TO STAY UP IN CANADA. MEANWHILE...THE
SHORTWAVE SEEN UP IN CENTRAL NORTH DAKOTA IS SLATED TO DROP INTO
CENTRAL MN BY 18Z...THEN PUSH EAST INTO LOWER MI. WITH THE UPPER
TROUGHING FORMING...EXPECT THE COLD FRONT TO CONTINUE MARCHING
SOUTHEAST. MODEL TIMING IS WELL AGREED UPON...AT 18Z STRETCHING FROM
OMAHA NEB TO VOLK FIELD WI AND MARINETTE WI...AND AT 00Z FROM
NORTHWEST MO TO NEAR DUBUQUE IA AND UP TO MANITOWOC WI.
HAZARDS...
ONGOING HEAT ADVISORY...DUE TO FRONTAL TIMING AND DRYING DEWPOINTS
BEHIND THE FRONT...HAVE CANCELLED SOME OF THE ADVISORY. AREAS
INCLUDE SOUTHEAST MN AND PORTIONS OF NORTHEAST IOWA INTO CENTRAL WI.
THERE ALSO IS A CHANCE FOR SEVERE WEATHER THIS AFTERNOON ALONG THE
COLD FRONT COMING THROUGH NORTHEAST IOWA AND SOUTHWEST WI. 0-6KM
SHEAR VALUES ARE HIGHER IN THE 09.00Z NAM...ORDER OF 30-40 KT VERSUS
20-30 KT IN THE 09.06Z RAP. IF SEVERE WEATHER OCCURS...DAMAGING
WINDS WOULD BE THE MAIN HAZARDS.
TODAY...
TWO BIG QUESTIONS...TEMPERATURES AND PRECIPITATION CHANCES. ON THE
PRECIPITATION SIDE OF THINGS...19.00Z GFS/NAM/REGIONAL CANADIAN ALL
WANT TO BRING THE SHOWERS AND SOME THUNDERSTORMS THROUGH THE
FORECAST AREA THIS MORNING PRIOR TO THE FRONTAL PASSAGE. THESE
ORIGINATE FROM ISENTROPIC LIFT ON THE 310 K SURFACE AHEAD OF THE
FRONT. IT APPEARS THESE SHOULD WEAKEN THROUGH THE MORNING TOO WITH
THE NOCTURNAL LOW LEVEL JET WEAKENING. A PERIOD OF CLEARING THEN
TAKES PLACE IN THE WARM SECTOR...WITH SOME HINTS FROM THE 19.00Z
GFS/REGIONAL CANADIAN AND 19.06Z RAP THAT THE FRONT COULD CONVECT IN
SOUTHEASTERN PORTION OF THE FORECAST AREA SAY BETWEEN 19-23Z. NOT
THRILLED ABOUT THE FRONT CONVECTING AS THE 0-2KM CONVERGENCE IS VERY
WEAK. HOWEVER...GIVEN MODELS HAVE BEEN SHOWING IT THE PAST FEW DAYS
AND PLENTY OF INSTABILITY PROGGED TO DEVELOP TODAY...KEPT SOME
CHANCES IN THE FORECAST. HAVE ALSO ADDED SOME LOW CHANCES OF
PRECIPITATION FOR THE AFTERNOON HOURS FROM TAYLOR COUNTY SOUTH TO
JACKSON. HERE ANOTHER FRONT LURKING UP IN NORTHERN MN IS PROGGED BY
THE 09.06Z RAP AND 09.05Z HRRR TO COME THROUGH AND HAVE SOME
CONVECTION ON IT. ON THE TEMPERATURE SIDE OF THINGS...A WARM START
PLUS 925MB TEMPS HOLDING IN THE 24-26C RANGE SHOULD EASILY ALLOWS
HIGHS TO REACH THE UPPER 80S TO POSSIBLY MID 90S AGAIN. THIS IS EVEN
DESPITE THE FRONTAL PASSAGE GIVEN THE WARM AIR STILL HOLDING BACK
AND LIKELY DEEPER MIXING BEHIND THE FRONT. HOWEVER...HEAT INDICES
WILL FALL WITH THE FRONT AS DRIER DEWPOINTS FLOW IN.
TONIGHT...
SUBSIDENCE AND DRYING COMING IN BEHIND THE COLD FRONT WILL ALLOW FOR
A MOSTLY CLEAR NIGHT ACROSS THE FORECAST AREA. DRIER AIR AND
DIMINISHING WINDS SHOULD ALLOW TEMPERATURES TO FALL CLOSE TO
GUIDANCE VALUES...IN THE UPPER 50S TO MID 60S...10-15 DEGREES COLDER
THAN TONIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 321 AM CDT FRI JUL 19 2013
SYNOPTIC OVERVIEW...
MUCH OF THE NEXT 6 DAYS LOOKS TO BE DOMINATED BY NORTHWEST FLOW
ACCORDING TO THE 19.00Z ECMWF/GFS/CANADIAN WITH RIDGING STAYING PUT
OVER THE WESTERN U.S.. THERE ARE SOME SIGNS FROM THE ECMWF THE RIDGE
MAY WANT TO BUILD EAST TOWARDS THE FORECAST AREA ON THURSDAY...BUT
PLENTY OF UNCERTAINTY ON THAT SEEING THE TROUGHING IN THE GFS.
ADDITIONALLY...THIS NORTHWEST FLOW HAS UNCERTAINTY IN TERMS OF
TIMING SHORTWAVES AND THE CHANCES OF PRECIPITATION WITH THEM.
SATURDAY THROUGH SUNDAY NIGHT...
MAIN FEATURE OF INTEREST DURING THIS PERIOD IS A SHORTWAVE ALL
MODELS HAVE TRACKING OUT OF MONTANA ON SATURDAY AND THROUGH THE
FORECAST AREA ON SUNDAY. SURPRISINGLY MODELS ARE IN REALLY GOOD
AGREEMENT WITH THIS SHORTWAVE...ALBEIT PERHAPS THE GFS HAS A BIT OF
CONVECTIVE FEEDBACK TO IT. IN ANY EVENT...INCREASING 310 K
ISENTROPIC LIFT COMBINED WITH INSTABILITY SHOULD INITIATE CONVECTION
OVER EASTERN SOUTH DAKOTA DURING THE AFTERNOON. THIS CONVECTION THEN
SPREADS TOWARDS THE FORECAST AREA SATURDAY NIGHT AS THE ISENTROPIC
LIFT AND 850MB MOISTURE TRANSPORT AHEAD OF THE SHORTWAVE SHIFTS
EAST. PERHAPS THERE IS A SHOT SOME HIGH BASED SHOWERS COULD DEVELOP
DOWNSTREAM OF THE CONVECTION SATURDAY AFTERNOON...BUT THINK THE BULK
OF THE PRECIPITATION WOULD WAIT UNTIL SATURDAY NIGHT. SUNDAY APPEARS
TO HAVE THE HIGHEST CHANCE OF RAIN WHERE DPVA ACCOMPANYING THE
SHORTWAVE INTERSECTS 850MB MOISTURE TRANSPORT CONTINUING TO AIM AT
THE AREA. ITS HARD TO SAY HOW SUNDAY NIGHT WILL EVOLVE. SUBSIDENCE
BEHIND THE SHORTWAVE MOVING THROUGH ON SUNDAY WOULD SEEM TO LIKELY
PROVIDE A DRY PERIOD...LIKE SUGGESTED BY THE 19.00Z NAM. HOWEVER...
THE 19.00Z GFS/ECMWF SHOW A POTENT SHORTWAVE TROUGH CROSSING
SOUTHERN MANITOBA SUNDAY NIGHT...WHICH INCREASES 850MB MOISTURE
TRANSPORT INTO THE AREA. THEREFORE...THESE MODELS WANT TO HANG ONTO
SOME SHOWERS. HAVE MAINTAINED SOME CHANCES OF PRECIPITATION TO
ACCOUNT FOR THE GFS/ECMWF SCENARIO. BIGGEST ISSUE IN THE TEMPERATURE
DEPARTMENT IS HIGHS ON SUNDAY. IF IT RAINS ALL DAY...TEMPERATURES
MAY GET STUCK IN THE UPPER 60S/LOW 70S. FOR NOW TRENDED HIGHS DOWN
SLIGHTLY.
MONDAY THROUGH THURSDAY NIGHT...
THIS PERIOD IS HIGHLY UNCERTAIN. 19.00Z GFS/ECMWF/CANADIAN SHOW
NUMEROUS SHORTWAVES MOVING THROUGH THE NORTHWEST FLOW ALOFT THROUGH
MUCH OF THE WEEK. TIMING AND TRACK OF THESE VARIES FROM RUN TO
RUN...THUS THE LOW CONFIDENCE. THERE DOES APPEAR TO BE SOME SIGNAL
FOR A COLD FRONT COMING THROUGH THE FORECAST AREA MONDAY
NIGHT...ASSOCIATED WITH THAT POTENT TROUGH OVER SOUTHERN MANITOBA
PROGGED TO LIFT EAST-NORTHEAST. IF THIS STAYS CONSISENT...WE MIGHT
BE ABLE TO DRY OUT TUESDAY. OTHERWISE...HAVE MAINTAINED A MODEL
CONSENSUS OF 20-40 PERCENT CHANCES THROUGH THURSDAY NIGHT. LIKELY
THE ENTIRE PERIOD WILL NOT BE WET...BUT HARD TO PIN POINT MUCH FOR
POSSIBLE DRY PERIODS BEYOND TUESDAY. WITH A NORTHWEST FLOW IN
PLACE...EXPECT A COOLER FLOW OF AIR. 850MB TEMPS ARE GENERALLY
PROGGED TO DROP FROM 18-20C ON MONDAY TO 12-15C FOR TUESDAY THROUGH
THURSDAY. THESE SHOULD RESULT IN A DROP IN HIGHS TO SLIGHTLY BELOW
NORMAL AFTER NEAR NORMAL ON MONDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1111 PM CDT THU JUL 18 2013
A COLD FRONT WILL SWEEP SOUTHEAST ACROSS THE REGION EARLY ON FRIDAY
MORNING...LIKELY AROUND THE 15Z TIME FRAME FOR KRST/KLSE...GIVE OR
TAKE AN HOUR. MOISTURE FIELDS AND BUFKIT SOUNDINGS SUGGEST MOSTLY
MID LEVEL/VFR CLOUDS WITH THE FRONT AS IT MOVES THROUGH...SCATTERING
OUT AS IT PASSES. SHOULD BE ENOUGH INSTABILTY AND LIFT IN THE
VICINITY OF THE FRONT FOR SCATTERED SHRA/TS. WHETHER THEY WILL
IMPACT KRST/KLSE IS STILL NOT CLEAR...SOME PCPN SHOULD BE IN THE
AREA. WILL GO WITH A MIX OF -SHRA/VCSH FOR NOW...LEAVING OUT A
MENTION OF TS AND ANY VSBY RESTRICTIONS FOR NOW. THIS WILL BE
ADJUSTED AS NEEDED BASED ON RADAR/MESO MODEL TRENDS.
FOR WINDS...SOUTH-SOUTHWEST WILL SWING TO THE NORTHWEST WITH THE
PASSAGE OF THE FRONT. BUFKIT SOUNDINGS CONTINUE TO SUGGEST LLWS WILL
BE A CONCERN...WITH NEAR 50 KTS OF WIND BY 2 KFT FOR A FEW HOURS AT
KRST AND AROUND 45 KTS AT KLSE OVERNIGHT. WILL CONTINUE LLWS MENTION
IN THE TAFS.
&&
.CLIMATE...
ISSUED AT 321 AM CDT FRI JUL 19 2013
LA CROSSE WI HAS ONLY SEEN 0.27 INCHES FOR THE MONTH OF JULY
THROUGH THE 18TH. THIS IS THE 5TH DRIEST START TO JULY. THE DRIEST
THROUGH JULY 18TH WAS 0.05 INCHES BACK IN 1896...AND THE LAST TIME
IT WAS THIS DRY WAS IN 1967. FOR REFERENCE...LA CROSSE NORMALLY
SHOULD HAVE 2.41 INCHES UP THROUGH THE 18TH.
ROCHESTER MN HAS HAD QUITE A BIT MORE RAIN...THUS THE 1.42 INCHES
OBSERVED THROUGH JULY 18TH IS WELL OUTSIDE THE TOP 20 DRIEST.
STILL ROCHESTER IS 1.25 INCHES BELOW NORMAL.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR WIZ041>044-053>055-
061.
MN...NONE.
IA...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR IAZ011-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION.....RIECK
CLIMATE...AJ
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
250 AM MST SUN JUL 21 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM IN MEXICO WILL CONTINUE TO SUPPLY MOISTURE TO
THE DESERT SOUTHWEST TODAY. HUMID CONDITIONS WILL RESULT IN
WELL-ABOVE NORMAL RAIN CHANCES AND WELL-BELOW NORMAL TEMPERATURES. A
DRYING TREND WILL BEGIN MONDAY...CONTINUING INTO WEDNESDAY AS
HIGH PRESSURE BUILDS BACK OVER THE REGION. MONSOON MOISTURE MOVING
BACK NORTHWARD INTO THE REGION IS LIKELY TO ONCE AGAIN INCREASE RAIN
CHANCES FOR THE END OF THE WEEK AND INTO THE WEEKEND.
&&
.DISCUSSION...
UPPER LOW CONTINUES TO SPIN WESTWARD INTO THE PACIFIC OCEAN JUST OFF
THE BAJA PENINSULA. FURTHER NORTH...THE MID-TROPOSPHERIC ANTICYCLONE
REMAINS POSITIONED ACROSS CA/NV. RESULTING MID-LEVEL EASTERLY FLOW
IS STRONGER THAN NORMAL (STANDARDIZED ANOMALY NEAR 1.0) AND
CONTINUES TO ADVECT DEEP SUB-TROPICAL MOISTURE INTO THE FORECAST
AREA. SURFACE DEWPOINTS ARE CURRENTLY IN THE LOWER 70S ACROSS THE
PHOENIX METRO AREA WHILE THE GPS-IPW REGISTERED AROUND 1.75
INCHES...WELL ABOVE NORMAL. LATEST RAP INDICATES THAT PWATS MAY BE
AS HIGH AS 2.0 TO 2.4 INCHES ACROSS THE SOUTHWEST DESERTS AND
TOWARDS PUERTO PENASCO.
LATEST WV IMAGERY SHOWS TWO MCSS...ONE ACROSS THE MOJAVE DESERT AND
THE OTHER ACROSS SOUTHERN AZ...BEARING DOWN ON SW AZ AND SE CA.
STRONG LOW-LEVEL CONVERGENCE IS EXPECTED EARLY THIS MORNING AND POPS
WERE INCREASED IN THESE AREAS. ACROSS SOUTH-CENTRAL AZ...NMM AND
WRF-BASED GUIDANCE CONTINUES TO SUGGEST THAT SHOWERS WILL REDEVELOP
AS EARLY AS THIS MORNING. THIS SEEMS REASONABLE GIVEN THE AMPLE
MOISTURE AND IT WILL ONLY TAKE A MINIMAL AMOUNT OF HEATING FOR
CONVECTION TO INITIATE. MODELS ALSO SUGGEST THAT VORTICITY-FORCED
ASCENT WILL AID IN THE DEVELOPMENT OF STORMS THIS AFTERNOON ACROSS
SE CA. ANY STORMS THAT DEVELOP WILL HAVE THE POTENTIAL TO PRODUCE
HEAVY RAIN AND LOCALIZED FLOODING. THE COPIOUS AMOUNT OF MOISTURE
WILL ALSO RESULT IN CONSIDERABLE CLOUDINESS ACROSS MUCH OF THE
AREA...WHICH WILL KEEP TEMPERATURES WELL BELOW NORMAL. FORECAST HIGH
FOR PHOENIX IS 95 DEGREES. A MAX TEMP THIS LOW HAS NOT OCCURRED SINCE
MAY 27.
A SIGNIFICANT DRYING TREND WILL TAKE PLACE MONDAY AS THE UPPER LOW
LIFTS STEADILY NORTHWARD. SHOWERS AND THUNDERSTORMS ARE STILL
ANTICIPATED...THOUGH COVERAGE WILL BE NOTICEABLY LESS THAN WHAT HAS
OCCURRED THE PAST FEW DAYS. THE UPPER LOW WILL BE PICKED UP BY THE
WESTERLIES TUESDAY AS THE MONSOON HIGH BECOMES REPOSITIONED ACROSS
THE ROCKIES. GFS/ECMWF DIFFER ON THE AMOUNT OF MOISTURE LEFT OVER
ACROSS THE DESERT SOUTHWEST THOUGH THE CONSENSUS IS THAT IT SHOULD
BE SUFFICIENT FOR ISOLATED THUNDERSTORMS THROUGH THE WEEK. FLOW WILL
BE WEAK AS AN ANTICYCLONE BUILDS BACK ACROSS AZ AND CONVECTION WILL
MAINLY BE RELEGATED TO THE HIGHER TERRAIN. A WARMING TREND IS ALSO
EXPECTED WITH A RETURN TO ABOVE NORMAL TEMPERATURES BY THURSDAY.
MODELS ARE IN GENERALLY GOOD AGREEMENT THAT ANOTHER PVD WILL SLIDE
WESTWARD THROUGH SONORA LATE IN THE WEEK...RESULTING IN AN INFLUX OF
MOISTURE. FORECAST IS FOR BELOW CLIMO POPS THROUGH
MIDWEEK...FOLLOWED BY NEAR CLIMO POPS THURSDAY THROUGH SUNDAY.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL...
VERY LOW CONFIDENCE AVIATION FORECAST FOR CNTRL ARIZONA THROUGH
SUNDAY AFTERNOON WITH THUNDERSTORM COVERAGE AND MOVEMENT COMPLETELY
DICTATING IMPACT TIMING AND DURATION. WHILE MOST TSTMS SHOULD
CONGEAL WEST OF THE TERMINALS...SCT ACTIVITY MOVING WEST FROM HIGHER
TERRAIN TO THE EAST COULD ARRIVE BETWEEN 02Z-06Z.
CONCURRENTLY...NUMEROUS OUTFLOW BOUNDARIES FROM CONVECTION
SURROUNDING THE AREA MAY CAUSE FREQUENTLY SHIFTING SFC WINDS
ORIENTED FROM MANY DIFFERENT DIRECTIONS. ATTEMPTED TO CAPTURE
GENERAL TRENDS IN THIS TAF PACKAGE...WITH THE EXPECTATION OF SEVERAL
AMENDMENTS BASED ON SHORT TERM TRENDS.
SEVERAL MODELS SUGGEST EXTENSIVE CLOUD COVER AND SHOWERS LINGERING
ACROSS CNTRL ARIZONA SUNDAY MORNING. HAVE ADDED A VCSH MENTION WITH
LOWERING CIGS...THOUGH KEPT HEIGHTS ABOVE 6K FT. THERE ARE
INDICATIONS CIGS COULD FALL BLO 6K FT FOR A PERIOD NECESSITATING
REDUCED ACCEPTANCE RATES...THOUGH CONFIDENCE WAS TOO LOW TO INCLUDE
AT THIS TIME.
SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH...
SCATTERED SHOWERS AND THUNDERSTORMS SHOULD BEGIN TO APPROACH SERN
CALIFORNIA TERMINALS LATER THIS EVENING AND OVERNIGHT. OVERALL
FORECAST CONFIDENCE IS RATHER LOW REGARDING THE COVERAGE AND TIMING
OF TSTMS AND AVIATION IMPACTS. HAVE ATTEMPTED TO INDICATE A TRENDS
OF SHIFTING WINDS AND VCTS/VCSH INTO TERMINAL TOWARDS THE LATE
EVENING AND OVERNIGHT HOURS. SHOWERS COULD LINGER INTO SUNDAY
MORNING...BUT DID NOT INCLUDE ANY MENTION IN THIS TAF PACKAGE GIVEN
EXTREMELY LOW CONFIDENCE.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
A SWITCH TO A SOUTHERLY FLOW ALOFT WILL BRING DRYING CONDITIONS AND
ENDING PRECIPITATION CHANCES ACROSS SOUTHEAST CALIFORNIA AND
SOUTHWEST ARIZONA. SLIGHT CHANCES FOR STORMS WILL CONTINUE ACROSS
SOUTH-CENTRAL ARIZONA WITH BETTER CHANCES ACROSS HIGHER TERRAIN
LOCATIONS NORTH AND EAST OF PHOENIX. HUMIDITIES WILL REMAIN ELEVATED
THROUGH THE ENTIRE PERIOD WITH AFTERNOON HUMIDITIES ONLY DROPPING
INTO THE 20-30 PERCENT RANGE WITH GOOD OVERNIGHT RECOVERY.
$$
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...HIRSCH
AVIATION...MO
FIRE WEATHER...KUHLMAN
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1026 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 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1023 PM MDT SAT JUL 20 2013
A LIGHT -TSRA WILL BE POSSIBLE AT KPUB THROUGH 07 UTC TONIGHT. THE
OTHER TWO TAF SITES WILL SEE NO SIGNIFICANT WEATHER.
FOR TOMORROW...VFR CONDITIONS IS EXPECTED. ISOLD -TSRA COULD OCCUR
BUT THE PROBABILITY OF IT OCCURRING IS TOO LOW TO MENTION
EXPLICITLY IN THE TAF. IF TSRA DO OCCUR...THEY WILL BE CAPABLE OF
LOCALLY GUSTY DOWNBURST WINDS.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...28
LONG TERM...PETERSEN
AVIATION...HODANISH
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
352 AM EDT Sun Jul 21 2013
.NEAR TERM [Today and Tonight]...
Rain coverage has diminished greatly between 04 and 06 UTC, with
much of the forecast area dry at the time this discussion was
composed (shortly after 06 UTC). GOES and RAP analyzed PWATs are
still around or just above 2" across much of our area, so we remain
in the midst of a plume of deep tropical moisture. Therefore, it is
unsurprising that the majority of model guidance indicates an early
start to showers today. Indications are that coverage may be higher
today to the north of an Apalachicola to Valdosta line, where
surface dewpoints and boundary layer mixing ratios (as analyzed by
the RAP) appear to be slightly higher. We expect low-topped
convective showers to increase in coverage in the western Florida
Panhandle 11-14 UTC and then gradually overspread the rest of the
area by 18/19 UTC. It appears to be more likely than not that most
people will see measurable rainfall, but the showers today should be
of a more scattered variety, and thus should not last very long at
individual locations. Still, when showers do occur, we should
continue to see heavy rain rates. PoPs were maintained ~60% over
much of the area. High temperatures may be slightly warmer today
with more breaks of sun - in the upper 80s in most locations.
&&
.SHORT TERM [Monday Through Tuesday]...
One item that keeps coming to mind if we are unable to shake this
wet and troughy pattern across the SE US (for the second consecutive
summer nonetheless), is that Tallahassee may soon become known as
the Seattle of the South, only with much more rainfall and higher
temps. Not really much else of value to add, other than that PoPs
will continue above climo and Max temps will continue below, and the
disturbed pattern and strong 1000-700mb Mean Layer Vector Winds will
make the Sea Breeze very difficult to develop.
&&
.LONG TERM [Tuesday Night through Friday]...
The GFS and ECMWF continue to agree that a broad long wave trough
will be the dominant large scale weather feature over the
Southeast. During this time there will likely be multiple minor
short waves rotating through the base of the trough, enhancing our
rain chances at times as both models forecast plenty of deep layer
moisture and CAPE. While the MOS PoP consensus is above
climatology, we will forecast a fairly diurnal cycle, with the
greatest PoP during the afternoon & evening hours (even though
sometimes MCS`s can affect our area overnight in this type of
pattern). Despite the above-climo PoPs, the MOS consensus high
temperatures are in the lower to mid 90s, which is near climo.
It`s interesting to note that the 1000-700mb lapse rates are
forecast to be steeper than normal (6-7 C/km) through much of this
period, with the GFS being the most unstable. While the mid
tropospheric winds are not expected to be very strong, the
thermodynamics may be more supportive of pulse severe storms than
what we have seen in recent days.
&&
.AVIATION [through 12 UTC Sunday]...
IFR or LIFR CIGS are expected at all of the terminals (ABY, DHN,
VLD, and TLH) except for ECP early this morning. Short term ensemble
guidance is in good agreement on that scenario. There may also be
some light fog, but most of the flight category reductions should be
due to low ceilings. The low CIGS should scatter out or lift to VFR
levels within a couple hours of sunrise. Expecting scattered +SHRA
today with a few TS. It should be an early start with morning rain
possible at ECP, DHN, and TLH, spreading to ABY and VLD in the
afternoon hours (with lingering SHRA possible at the other terminals
after 18z as well).
&&
.MARINE...
Light to moderate west to southwesterly winds and corresponding
seas are expected to continue through much of the period, as the
Synoptic scale pressure pattern remains a bit above normal from the
usual summer doldrums.
&&
.FIRE WEATHER...
Red flag conditions are not expected for the next several days.
&&
.HYDROLOGY...
Due to the recent heavy rainfall across the eastern Florida Big
Bend, area rivers are on the rise, and minor flooding could be
possible along parts of the Aucilla and Econfina rivers during the
next couple of days, although widespread additional heavy rainfall
is not expected at this time.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 89 73 89 73 90 / 60 20 60 40 60
Panama City 87 75 87 76 87 / 60 20 60 40 50
Dothan 88 72 89 72 91 / 60 30 70 40 60
Albany 89 73 89 73 91 / 60 30 60 40 60
Valdosta 89 72 90 73 90 / 60 20 60 40 60
Cross City 88 73 90 73 89 / 50 20 50 30 50
Apalachicola 86 75 87 76 86 / 50 20 50 30 50
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
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 MIAMI FL
137 AM EDT SUN JUL 21 2013
.AVIATION...
A CONVERGENT LINE OF SHOWERS AND STORMS REMAINED TO THE EAST OF
KPBI EARLY THIS MORNING. SOME OF THESE SHOWERS MAY GET NEAR KPBI
OVERNIGHT...SO ADDED VCSH. OTHERWISE...HIGH PRESSURE WILL CONTINUE
TO BUILD INTO SOUTH FLORIDA THROUGH THE TAF PERIOD WITH DRIER
CONDITIONS. LIGHT WINDS ARE EXPECTED THROUGH THE OVERNIGHT HOURS
AND AGAIN TONIGHT. SEA BREEZE BOUNDARIES ARE FORECAST TO PUSH
INLAND AT BOTH COASTS THIS AFTERNOON. SHOWER AND THUNDERSTORM
ACTIVITY IS FORECAST TO REMAIN MAINLY ACROSS THE INTERIOR...BUT
SHOWERS OR STORMS COULD GET NEAR KPBI AND KAPF IN THE AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 1027 PM EDT SAT JUL 20 2013/
UPDATE...
ONLY A FEW CHANGES WERE NECESSARY THIS EVENING BASED ON THE LATEST
TRENDS AND OBSERVATIONS AROUND THE LOCAL AREA. OTHERWISE...THE
PREVIOUS FORECAST PACKAGE REMAINS ON TRACK. THE AFTERNOON/EARLY
EVENING CONVECTION THAT MOSTLY IMPACTED THE INTERIOR AREAS AROUND
THE LAKE REGION HAS DIMINISHED. THE LATEST HRRR RUN HAS LINED UP
WELL WITH THE CURRENT CONDITIONS AND GENERALLY INDICATES A QUIET
NIGHT WITH THE EXCEPTION OF SOME SHOWERS DEVELOPING OVER THE
ATLANTIC WATERS THROUGH THE OVERNIGHT HOURS. FOR SUNDAY...DRIER
AIR WILL BEGIN TO SPREAD NORTH INTO THE AREA AS THE RIDGE BEGINS
TO BUILD OVERHEAD AND THE WEAK TROUGH LIFTS AWAY FROM THE AREA.
HOWEVER...LINGERING MOISTURE OVER THE NORTHERN HALF OF THE
CWA...OR AROUND THE LAKE REGION...WITH PWAT VALUES AROUND 2"
COMBINED WITH SW LOW-LEVEL FLOW WILL BE ENOUGH TO THE KEEP THE
AFTERNOON/EVENING SHOWERS/TSTMS IN THE FORECAST.
PREV DISCUSSION... /ISSUED 723 PM EDT SAT JUL 20 2013/
AVIATION...
OUTFLOW FROM INTERIOR CONVECTION IS MEETING DECAYING SEA BREEZE
BOUNDARY OVER THE EASTERN METROPOLITAN AREAS THIS EVENING...THUS
VCSH/VCTS IN TAFS BROWARD AND PALM BEACH COUNTIES TERMINALS.
OUTFLOW BOUNDARY SHOULD BRING A BRIEF PERIOD OF WNW WINDS TO
MIAMI-DADE TERMINALS...SO HAVE INCLUDED A TEMPO GROUP NOTING THE
WIND SHIFT. OTHERWISE...LIGHT ESE WINDS WILL PREVAIL...AT SPEEDS
OF AROUND 5 KTS TONIGHT AND 10 KTS ON SUNDAY. HAVE REMOVED VCSH
BEYOND MIDNIGHT...AS POPS OVER THE TERMINALS ARE BELOW 30 PERCENT
THROUGH SUNDAY.
PREV DISCUSSION... /ISSUED 213 PM EDT SAT JUL 20 2013/
SHORT TERM (TONIGHT-MONDAY NIGHT)...
A STRONG MID LEVEL RIDGE OVER THE MID ATLANTIC STRETCHES WEST TO
ACROSS CENTRAL/SOUTH FLORIDA WITH MID LATITUDE TROUGHS MOVING ACROSS
THE NORTHERN TIER OF STATES AND CANADA. A TROPICAL WAVE IS CURRENTLY
MOVING THROUGH THE WESTERN CARIBBEAN SOUTHWEST OF JAMAICA AND THE
NORTHERN EXTENT OF THIS WAVE IS LOCATED FROM THE EASTERN FLORIDA
STRAITS AND INTO THE BAHAMAS. THIS HAS INCREASED CONVECTIVE ACTIVITY
IN THAT REGION WITH HIGHER PWAT VALUES MOVING INTO SOUTH FLORIDA
WHICH IN TURN IS HELPING TO ENHANCE CONVECTION. THE 12Z MFL SOUNDING
WAS QUITE IMPRESSIVE AS REGARDS TO THE AVAILABLE CAPE BUT SO FAR THE
STORMS HAVE BEEN SOMEWHAT SUPPRESSED DUE TO THE WEAK MID LEVEL LAPSE
RATES ASSOCIATED WITH THE RIDGE AXIS. THE LOW LEVELS WERE VERY
UNSTABLE HOWEVER AND THIS AIDED IN AN EARLY START TO THE CONVECTION
PROCESS WITH STORM MOTION TO THE NORTHWEST DUE TO THE LOW LEVEL
SOUTHEAST FLOW. THE FLOW BECOMES VERY WEAK TO LIGHT SOUTHWEST IN THE
MID LEVELS IN RESPONSE TO THE RIDGE SO AS THE STORMS CONTINUE TO
GROW, THE INTERIOR COULD GET QUITE ACTIVE LATER THIS AFTERNOON AS
THE STORM MOTION BECOMES LESS THAN 5 MPH.
THE WAVE WILL CONTINUE TO MOVE WEST OF THE AREA ON SUNDAY BUT AS
MOISTURE CONTINUES TO LINGER ACROSS THE REGION WITH A WEAK SURFACE
TROUGH BOUNDARY REMAINING IN PLACE, SCATTERED SHOWERS/THUNDERSTORMS
ARE EXPECTED AGAIN BY LATE SUNDAY MORNING INTO THE AFTERNOON. DUE TO
THE WAVE BEING FARTHER TO THE WEST, THE LOW LEVEL SOUTHEAST FLOW
WILL BECOME SHALLOWER SO STORM MOTION WILL GO EVEN LIGHTER AND SEA
BREEZE BOUNDARIES WILL LIKELY BE THE DOMINANT FOCUSING MECHANISM. AT
THE SAME TIME, A SURFACE RIDGE WILL BUILD BACK ACROSS SOUTH FLORIDA
BY SUNDAY AFTERNOON THROUGH MONDAY AND THIS COULD SUPPRESS
CONVECTIVE ACTIVITY EVEN FURTHER WITH SEA BREEZE BOUNDARIES AGAIN
BEING THE MAIN FOCUS FOR MONDAY AFTERNOON.
LONG TERM (TUESDAY-SATURDAY)...
THIS SAME TREND WILL LIKELY CONTINUE THROUGH THE MIDDLE OF THE WEEK
AS A DEEP LAYER RIDGE BECOMES FIRMLY ESTABLISHED AND FORECAST
SOUNDINGS SHOW STORM MOTION 2 MPH OR LESS. A STRONG MID LEVEL TROUGH
WILL BEGIN TO DEEPEN INTO THE EASTERN STATES BY THURSDAY INTO THE
END OF THE WEEK AND INTO THE FIRST PART OF NEXT WEEKEND FOR A SLOW
RETURN TO STORM MOTION STEERING STORMS BACK TOWARDS THE EAST COAST.
FORECAST SOUNDINGS HOWEVER ARE NOT SHOWING A STRONG MOTION SO THE
ENTIRE WEEK LOOKS AS IF VERY SLOW STORM MOTION WILL CONTINUE A
THREAT FOR LOCALLY HEAVY RAINS WHERE EVER THE CONVECTION CAN SET UP.
MARINE...
GENERAL EAST TO SOUTHEAST WIND IS EXPECTED THROUGH TUESDAY AT
SPEEDS OF LESS THAN 15 KNOTS OUTSIDE OF SCATTERED
SHOWERS/THUNDERSTORMS. THE WIND WILL BEGIN TO VEER TO A SOUTH OR
SOUTHWEST DIRECTION LATER IN THE WEEK AS THE SURFACE RIDGE SHIFTS
TO THE SOUTH.
FIRE WEATHER...
NO PROBLEMS WITH PLENTY OF TROPICAL MOISTURE IN PLACE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 89 76 88 77 / 20 20 30 10
FORT LAUDERDALE 89 79 89 79 / 20 20 30 10
MIAMI 90 77 88 79 / 20 20 20 10
NAPLES 91 75 89 75 / 20 10 20 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...71/JE
AVIATION/RADAR...84/AK
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1150 PM CDT SAT JUL 20 2013
.DISCUSSION...
ISSUED 858 PM CDT SAT JUL 20 2013
SOMEWHAT COMPLICATED SCENARIO FOR THE OVERNIGHT AS OPPOSED TO THE
LAST SEVERAL NIGHTS. CONVECTION ALONG THE I-64 CORRIDOR HAS BEEN
PERSISTENT THE LAST FEW HOURS. ALTHOUGH THE HEAVIEST RAIN IS NOW
WELL SOUTH OF OUR AREA...THE EXTREME SOUTHEAST CWA HAS SEEN LIGHT
TO MODERATE RAIN CONTINUING. THE FRONTAL BOUNDARY HAS BEGUN TO
RETROGRADE WESTWARD...WITH IT APPEARING FAIRLY NICELY ON RADAR
IMAGERY FROM JERSEYVILLE TO DECATUR TO JUST WEST OF CHAMPAIGN.
LATEST RAP AND HRRR GUIDANCE DOES NOT SHOW MUCH IN THE WAY OF
STEERING CURRENTS WHICH WOULD FULLY PUSH IT BACK SOUTHEAST OF THE
AREA...BUT THEY INDICATE THAT IT SHOULD NOT GET TOO MUCH FURTHER
NORTHWEST. WITH LIGHT WINDS...POOLING DEW POINTS NEAR 70 AND THE
MOISTURE FROM THE HEAVIER RAIN POCKETS FROM EARLIER TODAY... HAVE
SOME CONCERNS WITH FOG DEVELOPMENT ACROSS THE SOUTHEAST THIRD OF
THE CWA DESPITE THE AMOUNT OF CLOUDS. HAVE ADDED SOME PATCHY FOG
FOR THIS AREA OVERNIGHT. DID NOT REALLY CHANGE THE LOW
TEMPERATURES...BUT HAD TO MAKE SOME SIGNIFICANT ADJUSTMENTS TO THE
HOURLY TRENDS...ESPECIALLY IN THE SOUTHEAST DUE TO THE RAIN.
UPDATED GRIDS HAVE BEEN SENT. EARLIER ZONE ISSUANCE AT 7 PM
ALREADY TOOK INTO ACCOUNT MOST OF THE UPDATES...BUT WILL FRESHEN
THIS AS WELL TO ADD THE FOG MENTION.
GEELHART
&&
.AVIATION...
ISSUED 1150 PM CDT SAT JUL 20 2013
MAIN CONCERN IS WITH FOG POTENTIAL OVERNIGHT...MAINLY IN EASTERN
ILLINOIS. HAVE ALREADY BEEN SEEING SOME CEILINGS BELOW 500 FEET AT
TIMES IN AREAS SOUTH AND SOUTHEAST OF KCMI. THIS IS EAST OF THE
FRONTAL BOUNDARY...WHERE TEMPERATURE/DEW POINT SPREADS ARE
MINIMAL...AND IN LOCATIONS THAT SAW POCKETS OF 1 TO 3 INCHES OF
RAIN ON SATURDAY. LATEST GUIDANCE FROM THE RAP/HRRR/LAMP MODELS
SHOWING AN EXPANDING AREA OF FOG OVER THE NEXT FEW HOURS IN EAST
CENTRAL ILLINOIS. HAVE HIT KCMI THE HARDEST WITH LIFR CONDITIONS
DEVELOPING BY AROUND 08Z AND PERSISTING INTO EARLY MORNING. KDEC
ALSO SHOWING SOME IFR POTENTIAL AND INCLUDED TEMPO PERIODS THERE
AS WELL. FORECAST SOUNDINGS AT KPIA/KBMI/KSPI ARE DRIER...AND HAVE
ONLY MENTIONED SOME 4SM VISIBILITIES AT TIMES.
LATER ON...CONVECTION CONCERNS PREVAIL FROM ABOUT 21Z ONWARD.
LATEST MODEL GUIDANCE IS EASING OFF SOME ON COVERAGE AND TIMING IN
MUCH OF CENTRAL ILLINOIS...WITH MORE OF A FOCUS JUST SOUTH OF THE
TAF SITES. HAVE MAINTAINED SOME VCTS MENTION AT KPIA/KSPI...BUT
LEFT OUT THUNDER MENTION ELSEWHERE FOR NOW DUE TO THE UNCERTAINTY.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 248 PM CDT SAT JUL 20 2013
MODELS LOOK IN VERY GOOD AGREEMENT IN THE SHORT TERM PERIOD...AS
MAIN CONCERN IS PCPN CHANCES AND TEMPS. EXTENDED MODELS HAVE SOME
DIFFERENCES BUT THEY ARE MINOR AND DO NOT CHANGE THE OVERALL
FORECAST THAT MUCH...EXCEPT TO BRING IN SOME DRIER PERIODS DURING
MIDDLE OF THE WEEK. SO OVERALL CONFIDENCE IN FORECAST IS GOOD.
SHORT TERM...TONIGHT THROUGH TUESDAY
FRONT HAS BEEN MOVING SOUTH THROUGH THE AREA TODAY AND WILL
CONTINUE TO MOVE SOUTH LATE THIS AFTERNOON AND EVENING.
THUNDERSTORMS HAVE DEVELOPED ALONG THE FRONT AS IT HAS INTERACTED
WITH JUICY AIR WITH LOWER TO MIDDLE 70S DEWPOINTS. WITH
THUNDERSTORMS THAT HAVE NOW DEVELOPED JUST NORTH OF I-70...WILL
HAVE A LATE AFTERNOON PERIOD IN THE WORDED FORECAST ONCE IT IS
ISSUED. OTHERWISE...TONIGHT THUNDERSTORMS WILL JUST BE IN THE
SOUTHEAST JUST FOR THIS EVENING AND THEN DRY FOR AFTER MIDNIGHT.
AS CAN BE SEEN ON VISIBLE SATELLITE AND RADAR IMAGES OUT
WEST...THE FRONT EXTENDS BACK TO THE NORTHWEST WITH MORE SHOWERS
AND THUNDERSTORMS. THIS FRONT WILL BE THE FOCUS FOR MORE
DEVELOPMENT TOMORROW THAT WILL ADVECT TOWARD WESTERN ILLINOIS
TOMORROW MORNING AND CENTRAL ILLINOIS TOMORROW AFTERNOON.
THUNDERSTORM CHANCES WILL CONTINUE INTO TOMORROW NIGHT AS A SHORT
WAVE MOVES ACROSS THE AREA AS WELL. POPS WILL BE HIGHEST TOMORROW
NIGHT DUE TO THIS SHORT WAVE AS WELL. PCPN CHANCES WILL CONTINUE
INTO MONDAY...THOUGH LOWER...AS THE SHORT WAVE MOVES EAST OF THE
AREA.
A SECOND WAVE OR MCS WILL THEN DEVELOP OUT WEST AND MOVE INTO THE
AREA FOR MON NIGHT INTO TUESDAY. THIS WILL BRING CONTINUED
THUNDERSTORM CHANCES FROM WEST TO EAST. CHANCES THEN DIMINISH FROM
THE WEST TUE INTO TUE NIGHT.
TEMP WILL REMAIN WARM AND WITH HIGH DEWPOINTS...MUGGY CONDITIONS
WILL CONTINUE. AFTERNOON HIGHS ARE EXPECTED TO STILL REACH INTO
THE MIDDLE TO UPPER 80S WITH NEAR 90 DEGREES IN THE SOUTHEAST ON
MONDAY.
LONG TERM...TUESDAY NIGHT THROUGH SATURDAY
AS THE SECOND WAVE MOVES THROUGH THE AREA...THUNDERSTORMS WILL
PROBABLY STILL BE POSSIBLE IN THE SOUTHEAST SECTIONS FOR TUE
NIGHT...SO WILL KEEP CHC POPS THERE. THIS SECOND WAVE SHOULD BE
STRONG ENOUGH TO PUSH THE FRONT WELL SOUTH AND BRING A PERIOD OF
DRY WEATHER TO THE AREA. UPPER LEVEL FLOW WILL ALSO BE OUT OF THE
NORTHWEST...SO CONDITIONS SHOULD BE A TAD COOLER DURING THE DAY.
CURRENT EXTENDED MODELS INDICATE THAT DRY WEATHER WILL PREVAIL
THROUGH THURSDAY NIGHT AS MODELS DO NOT SHOW ANY SHORT WAVES
MOVING THROUGH THE AREA DURING THAT PERIOD. HOWEVER...MODELS DO
NOT DO WELL WITH SMALL WEAK FEATURES IN NORTHWEST FLOW SO DON`T BE
SURPRISED IF THIS CHANGES OVER THE NEXT COUPLE OF DAYS. THE NEXT
REAL CHANCE OF SHOWERS AND THUNDERSTORMS APPEARS NOT TO BE UNTIL
FRIDAY THROUGH SATURDAY AS A MID LEVEL TROUGH MOVES TOWARD THE
AREA. CURRENTLY THIS SYSTEM LOOKS TO REMAIN WEST OF THE AREA BUT
STILL BRING PCPN TO ALL OF CENTRAL AND SOUTHEAST ILLINOIS FOR END
OF THE WEEK.
TEMPS WILL REMAIN AROUND NORMAL BUT THEN BECOME COOLER...
POSSIBLY...AT THE END OF THE WEEK AND BEGINNING OF THE WEEKEND.
AUTEN
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
318 AM CDT SUN JUL 21 2013
.SYNOPSIS...
ISSUED AT 252 AM CDT SUN JUL 21 2013
A QUIET NIGHT ACROSS THE AREA WHILE THUNDERSTORMS RAIN OVER THE
CENTRAL PLAINS. THE SURFACE AND 850 MB FRONTAL BOUNDARIES RESIDE
TO OUR SOUTH IN NORTHERN MISSOURI AND ARE ASSOCIATED WITH
WEAKENING STORMS. ANOTHER BOUNDARY TO OUR NORTH ACROSS MINNESOTA AND
WISCONSIN IS ASSOCIATED WITH ACTIVE STORMS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 252 AM CDT SUN JUL 21 2013
MAIN CONCERN IN THIS TIME FRAME IS THUNDERSTORM CHANCES TODAY AND
THIS EVENING. MODELS OTHER THAN THE RAP AND HRRR HAVE A WEAK
HANDLE ON THE PLAINS CONVECTION. AND THIS SYSTEM WITH ITS ASSOCIATED
SHORT WAVE TROUGH/MCV WILL BE OUR WEATHER MAKER FOR TODAY.
OVERALL CURRENT CONVECTIVE TRENDS IN THE PLAINS ARE WEAKENING
EXCEPT FOR REDEVELOPING STORMS ON THE TAIL OF THE MCS WHICH IS
REACHING THE MISSOURI RIVER. TIMING OF THE SHORT WAVE INTO OUR
AREA IS SUCH THAT THE ATMOSPHERE SHOULD DESTABILIZE THROUGH THE
MORNING...ALBEIT WITH SUNSHINE FILTERED BY MID AND HIGH CLOUDS.
MODELS SEEM TO WEAKEN THE WAVE...AND THE NAM EVEN TAKES IT SOUTH
OF THE CWA. BUT THE ATMOSPHERE SHOULD BE PRIMED FOR CONVECTION...
AND IF THE SURFACE AND 850MB FRONTS ARE PULLED NORTH WITH THE
TROUGH...WE WILL HAVE A FOCAL POINT FOR STORM INITIATION. SINCE
FLOW IS WEAK AND MODEL FORECASTS ARE DIVERGENT ON THIS ISSUE...
HAVE GENERALLY HELD POPS IN THE HIGH CHANCE RANGE. SLOW MOVING
STORMS COULD PRODUCE LOCALLY HEAVY RAIN...AND THE ENVIRONMENT
SUPPORTS AN ISOLATED RISK OF DOWNBURSTS.
MAX TEMPS TODAY RELATIVE TO YESTERDAY WILL BE HINDERED SOME BY
CLOUD COVER. OVERNIGHT LOWS WILL BE MORE REFLECTIVE OF THE WARM
SECTOR IN MISSOURI AS WINDS SHIFT TO THE SOUTH TONIGHT. WOLF
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 252 AM CDT SUN JUL 21 2013
THE DEEP MOIST AIR MASS AHEAD OF AN EARLY TUE FROPA WILL CONTINUE
THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS MONDAY INTO MONDAY
NIGHT. DEVELOPING NW ALOFT AND HIGH PRESSURE TO THEN PROVIDE DRY
WEATHER AND SLIGHTLY COOLER TEMPERATURES FOR MOST OF THE UPCOMING
WORKWEEK. RAIN CHANCES RETURN LATE WEEK INTO THE WEEKEND WITH
TEMPERATURES POSSIBLY TRENDING WELL BELOW NORMAL BY SUNDAY.
MONDAY...WEAK MID LEVEL SUBSIDENCE AND LACK OF SIGNIFICANT SURFACE
BOUNDARIES WILL BE UNFAVORABLE FOR ANYTHING BEYOND ISOLATED
CONVECTION OVER MOST OF THE AREA AND HAVE LOWERED POPS TO SLIGHT
CHANCES FOR MOST OF THE DAY. THE EXCEPTION IS ACROSS THE FAR
NW...WHERE DEVELOPING LIFT AHEAD OF AN APPROACHING SHORTWAVE AND
SURFACE COLD FRONT MAY LEAD TO THUNDERSTORMS DURING LATE DAY PEAK
HEATING AND HAVE CHANCE POPS. PREFRONTAL WARMING AND WEDGE OF WARM
AIR AT 850 MB WILL SUPPORT HIGHS FROM THE MID 80S NORTH TO AROUND 90
SOUTH. DEW POINTS IN THE UPPER 60S TO LOWER 70S MAY DRIVE HEAT
INDEX READINGS INTO THE UPPER 90S ACROSS THE SOUTH.
MONDAY NIGHT INTO EARLY TUESDAY...THERE IS A SIGNIFICANT SPREAD
AMONG THE MODELS WITH THE TIMING OF THE SURFACE COLD FRONT. THE GFS
HAS TRENDED THE SLOWEST...NOT BRINGING THE FRONT THROUGH UNTIL MID
MORNING...WHILE THE ECMWF HAS THE SURFACE WIND SHIFT WELL BEFORE
SUNRISE. WILL STAY CLOSER TO A FASTER CONSENSUS KEEPING CHANCE POPS
FOCUSED ON THE OVERNIGHT PERIOD...FOLLOWED BY SLIGHT CHANCES OVER
MAINLY THE EAST TUESDAY MORNING. WILL CONTINUE TO HAVE A THREAT FOR
LOCALLY HEAVY RAINFALL DUE TO THE HIGH PW VALUES IN PLACE MONDAY
NIGHT. KEPT MINS FROM THE MID 60S NORTH TO THE LOWER 70S SOUTH.
TUESDAY THROUGH THURSDAY...CANADIAN HIGH PRESSURE BUILDS SOUTH INTO
GREAT LAKES UNDER A NW FLOW ALOFT TO PROVIDE A PERIOD OF SEASONABLY
MILD AND LESS HUMID CONDITIONS. WED LOOKS TO BE THE COOLEST AS THE
POSITIONING OF THE PASSING HIGH WILL PROVIDE A LOW LEVEL NORTHEAST
FETCH AND THE COOLEST TEMPERATURES AT 850 MB. THIS MAY RESULT IN
HIGHS LIMITED TO THE 70S ACROSS THE CENTRAL AND NORTH...WHILE BOTH
TUE AND THU WILL LIKELY SEE WIDESPREAD LOWER TO MID 80S. THIS
SEASONABLY DRY AIR MASS WILL SUPPORT LOWS IN THE 60S WITH SOME
POCKETS OF 50S POSSIBLE THU MORNING.
GULF MOISTURE RETURNS TO THE REGION THU NIGHT INTO FRIDAY. THIS AND
A COLD FRONT SHOWN PUSHING THROUGH FRIDAY NIGHT OR SATURDAY WILL
BRING THUNDERSTORM CHANCES BACK TO THE AREA. THE LATEST GFS AND
ECMWF THEN DEVELOP A SIGNIFICANT UPPER TROUGH OVER THE EASTERN U.S.
THAT ALLOWS HIGH PRESSURE TO SPILL INTO THE MID MS VALLEY. THIS
COULD LIMIT HIGHS TO THE 70S OVER THE WEEKEND WITH LOWS IN THE 50S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1142 PM CDT SAT JUL 20 2013
WINDS WILL REMAIN LIGHT EAST OR SOUTHEAST TONIGHT AND SUNDAY WITH
WEAK HIGH PRESSURE REMAINING OVER THE WESTERN GREAT LAKES. WITH
THE RAINS AT KDBQ THIS AFTERNOON AND WITH SCATTERED CLOUDS AND
LIGHT WINDS OVERNIGHT THE MVFR VSBYS IN FOG WERE MAINTAINED FOR KDBQ
LATE TONIGHT. TONIGHT SHOULD BE DRY FOR MOST OF THE THE FORECAST
AREA. THERE IS A LOW CHANCE OF SOME SHRA/TSRA MOVING INTO THE
HIGHWAY 20 CORRIDOR INCLUDING KDBQ EARLY SUNDAY MORNING OTHERWISE
THE REST OF THE AREA SHOULD BE DRY THROUGH MUCH OF THE MORNING.
SHRA/TSRA SHOULD DEVELOP OR SPREAD INTO THE AREA BY LATE MORNING
WITH THE BEST CHANCE OF PRECIPITATION LATE SUNDAY AFTERNOON AND EVENING.
FOR NOW HAVE JUST MENTIONED MVFR CONDITIONS IN TSRA LATE SUNDAY
AFTERNOON.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...WOLF
SHORT TERM...WOLF
LONG TERM...SHEETS
AVIATION...DLF
AREA FORECAST DISCUSSION
NWS TOPEKA KS
353 AM CDT SUN JUL 21 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CDT SUN JUL 21 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...(MONDAY THROUGH SATURDAY)
ISSUED AT 345 AM CDT SUN JUL 21 2013
SHORTWAVE TROUGHS EMBEDDED IN THE WEST TO NORTHWEST FLOW ALOFT
WILL CONTINUE TO MOVE ACROSS THE AREA MAINTAINING A RATHER
UNSETTLED PATTERN FOR PERIODIC CHANCES FOR THUNDERSTORMS. ALTHOUGH
MONDAY MORNING MAY START DRY...MODELS ARE CONSISTENT WITH BACKING
THE LLVL FLOW IN RESPONSE TO THE NEXT UPSTREAM WAVE. AS THIS
OCCURS ISENTROPIC LIFT AND CONVERGENCE BEGIN TO INCREASE ACROSS
MAINLY EAST CENTRAL AND NORTHEAST KS THROUGH THE DAY...SO THE
POTENTIAL IS THERE FOR SOME ISOLATED DEVELOPMENT AS THE DAY
PROGRESSES. INSTABILITY WILL BE VERY HIGH...SO ANY STORM THAT DOES
DEVELOP COULD BE STRONG. LINGERING CLOUDS/ISOLATED CONVECTION MAY
COMPLICATE STRONG WARM AIR ADVECTION AND HIGHS EAST. STILL EXPECT
A WARM AND HUMID DAY WITH HIGHS IN THE MIDDLE TO UPPER 90S AND
HEAT INDICES AROUND 100 DEGREES. BETTER COVERAGE OF THUNDERSTORMS
IS EXPECTED INTO THE EVENING AND OVERNIGHT AS CONVECTION INCREASES
ALONG THE FRONT TO THE NORTH IN RESPONSE TO THE SHORTWAVE TROUGH
APPROACHING FROM THE NORTHWEST. WITH INCREASING FLOW ALOFT...SHEAR
PROFILES WILL BE MORE SUPPORTIVE OF STRONGER CONVECTION WITH HAIL
AND STRONG WINDS AS THE CONVECTION DEVELOPS/SPREADS SOUTHEASTWARD.
HIGHS IN THE WAKE OF THE CONVECTION FOR TUESDAY WILL BE SIMILAR OR
ONLY SLIGHTLY COOLER THAN MONDAY WITH READINGS IN THE LOW TO
MIDDLE 90S AND LINGERING SLIGHT CHANCE FOR THUNDERSTORMS.
A STRONGER SHORTWAVE WILL THEN MOVE THROUGH THE AREA TUESDAY
NIGHT/EARLY WEDNESDAY WITH A BETTER CHANCE FOR MORE WIDESPREAD
SHOWERS AND THUNDERSTORMS. IT WILL ALSO PROVIDE A STRONGER PUSH
TO THE FRONT SOUTHWARD THROUGH THE CWA...SO COOLER HIGHS IN THE
MIDDLE TO UPPER 80S ON TRACK FOR WEDNESDAY. CONVECTION SHOULD MOVE
SOUTH AND EAST OF THE CWA BY WEDNESDAY AFTERNOON AND NIGHT BEFORE
ANOTHER WAVE MOVES OUT OF THE ROCKIES AND INTO THE PLAINS IN THE
THURSDAY NIGHT/FRIDAY TIMEFRAME WITH THE NEXT SIGNIFICANT CHANCE
FOR THUNDERSTORMS. WILL KEEP A LINGERING LOW CHANCE FOR
THUNDERSTORMS INTO SATURDAY...BUT BETTER CHANCES FOR PRECIP AT
THAT TIME MAY OCCUR FURTHER TO THE WEST IN UPSLOPE FLOW OVER THE
HIGH PLAINS. HIGHS WILL REMAIN GENERALLY IN THE 80S THROUGH THE
END OF THE WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1156 PM CDT SAT JUL 20 2013
FOR THE 06Z TAFS...MAIN FOCUS IS ON THE POTENTIAL FOR ADDITIONAL
SHOWERS AND THUNDERSTORMS TO DEVELOP NEAR THE TAF SITES. A COMPLEX
OF THUNDERSTORMS WAS TRACKING SOUTHEAST ACROSS CENTRAL
NEBRASKA...AND IF THIS ACTIVITY HOLDS TOGETHER IT IS EXPECTED TO
PROGRESS INTO THE REGION DURING THE OVERNIGHT HOURS WITH SCATTERED
PRECIPITATION PERSISTING THROUGH THE MORNING HOURS. HOWEVER...THERE
IS STILL A UNCERTAINTY WITH REGARDS TO THE TIMING AND LOCATION OF
ANY PRECIPITATION THAT DEVELOPS OVERNIGHT AND THROUGH THE DAY ON
SUNDAY. CURRENTLY HAVE DRY CONDITIONS FOR THE AFTERNOON AND EVENING
HOURS...BUT SOME MODELS SUGGEST SCATTERED ACTIVITY WILL PERSIST SO
WILL CONTINUE TO MONITOR THIS POTENTIAL WITH FURTHER UPDATES. IN
GENERAL...WINDS THROUGH THE PERIOD WILL BE OUT OF THE SOUTH AND
SOUTHEAST...HOWEVER VARIABLE WINDS CAN BE EXPECTED IN AREAS OF
THUNDERSTORM DEVELOPMENT.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GARGAN
LONG TERM...63
AVIATION...HENNECKE
AREA FORECAST DISCUSSION
NWS JACKSON KY
142 AM EDT SUN JUL 21 2013
.UPDATE...
ISSUED AT 142 AM EDT SUN JUL 21 2013
MADE A FEW TWEAKS TO THE FORECAST FOR THE 24 HOUR PERIOD BEGINNING
WITH 12Z TODAY. TRIED TO CAPTURE THE EVOLUTION OF ONGOING SHOWER AND
STORM ACTIVITY THAT IS MOVING ACROSS CENTRAL KENTUCKY. THE MODELS
HAVE ALL PRODUCED VERY DIFFERENT SOLUTIONS REGRADING TIMING OF SHOWER
AND STORM ACTIVITY AND OVERALL AREAL COVERAGE. IN THE END...DECIDED
TO GO WITH A MODIFIED VERSION OF THE LATEST NAM12 AND SREF MODEL
RUNS. OVERALL IT WILL BE QUITE CHALLENGING TO DETERMINE WHEN AND
WHERE SHOWERS AND STORMS WILL FORM ACROSS THE AREA AND HOW THEY WILL
PROGRESS ONCE THEY HAVE FORMED. MADE TWEAKS TO THE SKY
COVER...QPF...AND WEATHER GRIDS FROM 12Z ONWARD. WILL TAKE A LOOK AT
THE OTHER FORECAST ELEMENTS ONCE THE TAF DISCUSSION HAS BEEN ISSUED.
OVERALL IT APPEARS THAT SCATTERED TO NUMEROUS SHOWERS AND STORMS WILL
MOVE ACROSS EASTERN KENTUCKY DURING THE DAY TIME HOURS...WITH LOCALLY
HEAVY RAINFALL AND GUSTY WINDS POSSIBLE WITH SOME OF THE STORMS. THE
CULPRIT FOR ALL THIS WEATHER WILL BE A COLD FRONT THAT IS EXPECTED TO
MOVE SLOWLY SOUTHWARD ACROSS THE AREA TODAY.
UPDATE ISSUED AT 1025 PM EDT SAT JUL 20 2013
MOST SHOWERS AND THUNDERSTORMS HAVE DIMINISHED TO OUR NORTH AND EAST.
HOWEVER...A LARGE LINE OF WEAK CONVECTION HAS DEVELOPED TO OUR WEST
AND CONTINUES TO SLOWLY MAKE ITS WAY EASTWARD. EXPECT SOME CONTINUED
WEAKENING BY THE TIME IT REACHES EASTERN KY...THOUGH LOW END
CHANCES/SCT COVERAGE IS STILL WARRANTED BASED ON LATEST MODEL RUNS.
UPDATED POPS TO REFLECT THIS LATEST RADAR TREND...WITH SCT CHANCES
MOVING IN ACROSS THE WESTERN CWA IN THE NEXT COUPLE OF HOURS...AND
THEN SPREADING ACROSS THE REMAINING CWA BY LATE TONIGHT.
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 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 142 AM EDT SUN JUL 21 2013
A WEAK COLD FRONT WILL PUSH SOUTHEAST AND STALL OVER NORTHERN
KENTUCKY THROUGH THE REMAINDER OF THE OVERNIGHT. SCATTERED SHOWERS
AND STORMS CONTINUE TO FIRE IN WESTERN AND CENTRAL TENNESSEE AND
CENTRAL KENTUCKY. THESE SHOWERS AND STORMS WILL GRADUALLY MAKE THERE
WAY INTO THE FORECAST AREA OVERNIGHT...AND SHOULD INCREASE IN
COVERAGE ONCE THE SUN COMES UP AND A COLD FRONT SITUATED TO OUR NORTH
BEGINS TO MOVE SOUTHWARD OUT OF THE OHIO VALLEY. SHOWERS AND STORMS
ARE EXPECTED TO PERSIST THROUGH THE AFTERNOON AND EVENING HOURS
TODAY...AS THE AFOREMENTIONED COLD FRONT EVOLVES INTO A WARM FRONT
AND BEGINS TO DRIFT NORTHWARD ACROSS THE AREA. IN GENERAL...VFR
CONDITIONS WILL PREVAIL AT THE TAF SITES FOR THE REST OF THE NIGHT.
CONDITIONS WILL BEGIN TO DETERIORATE A BIT AS SHOWERS AND STORMS
BECOME MORE NUMEROUS DURING THE DAY...WITH MVFR CONDITIONS POSSIBLE
AT TIMES.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR
SHORT TERM...KAS
LONG TERM...GREIF
AVIATION...AR
AREA FORECAST DISCUSSION...UPDATED
NWS PADUCAH KY
1200 AM CDT SUN JUL 21 2013
.UPDATE...
ISSUED AT 1155 PM CDT SAT JUL 20 2013
UPDATED THE AVIATION SECTION FOR THE 06Z TAF ISSUANCE.
&&
.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 1155 PM CDT SAT JUL 20 2013
POSSIBLE MVFR FOG BETWEEN 08-12Z...OTHERWISE VFR CONDITIONS
SHOULD PREVAIL THROUGH MOST OF THE PERIOD. VCSH/VCTS POSSIBLE AFT
13Z. POSSIBLE MVFR CIGS/VSBYS IN TSRA AFT 00Z. LIGHT AND VARIABLE
WINDS WILL BECOME SOUTHWEST AOB 10 KTS AFT 13Z.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
PUBLIC...DB
AVIATION...JP
AREA FORECAST DISCUSSION
NWS CARIBOU ME
108 AM EDT SUN JUL 21 2013
.SYNOPSIS...
A STRONG COLD FRONT WILL CROSS THE REGION OVERNIGHT. A DRIER AND
COOLER CANADIAN AIR MASS 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/...
105 AM UPDATE...NO SIGNIFICANT CHANGES WERE NEEDED FOR THIS
UPDATE. DRIER AIR CONTINUES TO SPILL INTO THE FORECAST AREA, WITH
DEWPOINTS DROPPING INTO THE 40S AND 50S. AS SUCH, TONIGHT WILL BE
A MUCH COOLER AND MORE COMFORTABLE NIGHT. SKIES HAVE BECOME CLEAR
OVER ALL BUT THE FAR DOWNEASTERN AREAS, AND THESE CLOUDS SHOULD
PUSH OFFSHORE BY DAWN. THE GOING FORECAST HAS THIS ALL COVERED, SO
ONLY MADE SLIGHT ADJUSTMENTS TO MIN TEMPS TO MATCH CURRENT OBS.
PREVIOUS DISCUSSION...
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 /TONIGHT THROUGH 6 PM MONDAY/...
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 /MONDAY 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 /05Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: VFR THROUGH 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 RUNNING AROUND 4 FT AT THE EASTERN MAINE SHELF
THIS EVENING. 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...HASTINGS/HEWITT
SHORT TERM...BLOOMER
LONG TERM...BLOOMER
AVIATION...HASTINGS/HEWITT/BLOOMER
MARINE...HASTINGS/HEWITT/BLOOMER
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
451 AM EDT SUN JUL 21 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 450 AM EDT SUN JUL 21 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A ZONAL FLOW OVER THE UPPER
GREAT LAKES. AT THE SFC...HIGH PRESSURE DOMINATES THE UPPER GREAT
LAKES. THE CLEAR SKIES AND LIGHT WINDS HAVE ALLOWED TEMPS EARLY THIS
MORNING TO FALL INTO THE 40S WITH EVEN A FEW LOCATIONS REACHING THE
MID TO UPPER 30S.
TODAY...AS THE SFC HIGH SHIFTS EAST OF THE AREA...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 INDICATE SOME INCREASE IN 305K ISENTROPIC ASCENT OVER FAR WRN
UPR MI LATE IN THE DAY ALTHOUGH BEST MOISTURE LIFT SHOULD STAY SOUTH
AND WEST. WILL MAINTAIN GOING FCST OF SLIGHT CHANCE POPS OVER THE
FAR WEST.
TONIGHT...INCREASING 925-700 MB THETA-E ADVECTION AND 305K
ISENTROPIC ASCENT SHOULD LEAD TO INCREASED CHCS FOR SHRA AND TSRA
ESPECIALLY AFT MIDNIGHT AS SHORTWAVE APPROACHED FM THE WEST.
LIMITING FACTOR FOR TSRA WILL BE LACK OF ELEVATED INSTABILITY AS
MUCAPES ONLY A FEW HUNDRED J/KG. WILL KEEP HIGHER CHC POPS OVER FAR
WEST AND TAPER TO LOW CHC 20-30 PCT POPS OVER CENTRAL COUNTIES.
EXPECT LOWS GENERALLY IN THE 50S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 450 AM EDT SUN JUL 21 2013
MOST TIME SPENT ON LONG TERM WAS WITH PRECIP CHANCES MON/MON NIGHT
AND ASSESSING SEVERE STORM THREAT FOR MON AFTERNOON/EVENING.
LOOKING FIRST AT THE LARGE SCALE...AN UPPER TROUGH OVER THE ERN HALF
OF THE CONUS WILL BE STEMMING FROM A CLOSED LOW OVER NRN QUEBEC AND
AN UPPER RIDGE WILL BE OVER THE WRN CONUS AT 12Z MON. A PIECE OF
UPPER ENERGY WILL MOVE ACROSS THE REGION MON INTO EARLY MON
NIGHT...FOLLOWED BY OTHER SMALLER SCALE ENERGY THU NIGHT THROUGH
SAT...BUT THE OVERALL PATTERN REMAINS SIMILAR THROUGH THE EXTENDED.
THIS MEANS...FOR THE MOST PART...THAT COOLER WEATHER IS HERE TO STAY
FOR MUCH OF THE NEXT WEEK AT LEAST.
FOR THE SPECIFICS...
MON/MON NIGHT...THERE WILL BE PRECIP MOVING INTO THE WRN CWA EARLY
MON AS THE UPPER TROUGH AND SFC TROUGH/COLD FRONT MOVE IN. THINK THE
BEST PRECIP CHANCES WILL BE DURING THE AFTERNOON/EARLY EVENING AS
THE COLD FRONT MOVES THROUGH A POTENTIALLY UNSTABLE AIRMASS.
QUESTIONS IS HOW MUCH CLEARING WILL RESULT AFTER MORNING
RAIN...WHICH WILL EFFECT HOW MUCH INSTABILITY EXISTS IN THE
AFTERNOON. IF WE CAN GET GOOD CLEARING...SBCAPE VALUES MAY BE
800-1200J/KG /HIGHEST OVER SCENTRAL UPPER MI/...AND STRONGLY VEERING
WINDS THROUGH THE ATMOSPHERE WILL LEAD TO AROUND 40KTS OF 0-6KM BULK
SHEAR. IF OPTIMAL CONDITIONS FOR CONVECTION DO MATERIALIZE...THEN
SEVERE THUNDERSTORMS WITH LARGE HAIL AND DAMAGING WINDS WOULD BE
POSSIBLE...WITH THE BEST CHANCES OVER SCENTRAL UPPER MI.
HOWEVER...AT THIS TIME...THINK THE COVERAGE OF ANY SEVERE WEATHER
WILL BE MORE LIMITED DUE TO DRY AIR. FOR NOW WILL CONTINUE MENTION
OF SEVERE CHANCES IN HWO/EHWO BUT STILL TOO UNCERTAIN TO PUT IN
GRIDS. MON LOOKS LIKE THE WARMEST DAY IN THE NEXT WEEK AHEAD OF THE
COLD FRONT...WITH HIGHS IN THE 70S TO MID 80S.
POSTFRONTAL TUESDAY SHOULD BE COOLER AND SIMILAR TO YESTERDAY...WITH
HIGHS AROUND 60 NEAR LAKE SUPERIOR TO THE LOW 70S SOUTH CENTRAL.
SKIES SHOULD BE CLEARING BY THE AFTERNOON.
WED WILL BE SLIGHTLY WARMER THAN TUESDAY AS TEMPS RECOVER SOME FROM
THE COLD FRONT. SHOULD SEE SOME INCREASE IN CLOUDS FROM W TO E
DURING THE AFTERNOON/EVENING AS A MORE MILD PIECE OF UPPER ENERGY
SLIDES ACROSS THE CWA...BUT NO PRECIP IS EXPECTED.
THERE IS MORE UNCERTAINTY LATER IN THE WEEK WHEN LOOKING AT MORE
SIGNIFICANT UPPER ENERGY SLIDING INTO THE REGION...BUT PRECIP WILL
CERTAINLY BE POSSIBLE LATER INTO THE WEEK. TEMPERATURES WILL CLIMB
ANOTHER COUPLE OF DEGREES ON THURSDAY...BUT SHOULD AGAIN FALL INTO
THE WEEKEND AS THE UPPER TROUGH MOVES OVERHEAD. USED A GENERAL
CONSENSUS OF MODEL GUIDANCE FOR THIS PART OF THE FORECAST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 141 AM EDT SUN JUL 21 2013
VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD AS HIGH
PRESSURE REMAINS OVER THE REGION.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 450 AM EDT SUN JUL 21 2013
HIGH PRESSURE WILL KEEP WINDS GENERALLY LIGHT TODAY OVER THE
NORTHERN GREAT LAKES. SRLY WINDS WILL INCREASE TO AROUND 20 KNOTS
LATE TONIGHT AND MONDAY AHEAD OF A LOW PRESSURE TROUGH MOVING
THROUGH THE AREA. NORTH TO NORTHWEST WINDS WILL THEN INCREASE TO 20
KNOTS BY LATE MONDAY NIGHT INTO TUESDAY BEHIND THE TROUGH/COLD FRONT
MOVING THROUGH THE REGION. WINDS ARE THEN EXPECTED TO REMAIN BELOW
20 KNOTS TUE NIGHT THROUGH THURSDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...TITUS
AVIATION...07
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
141 AM EDT SUN JUL 21 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 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 141 AM EDT SUN JUL 21 2013
VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD AS HIGH
PRESSURE REMAINS OVER THE REGION.
&&
.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...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
400 AM CDT SUN JUL 21 2013
.SHORT TERM...(THROUGH LATE TONIGHT)
ISSUED AT 342 AM CDT SUN JUL 21 2013
EARLY THIS MORNING...A STALLED OUT AND WEAKLY-DEFINED SFC FRONTAL
BOUNDARY EXISTED JUST N OF THE INTERSTATE 70 CORRIDOR. PCPN THAT
HAD DEVELOPED EARLIER IN THE NIGHT IN THE AIRMASS NEAR IT OR TO THE
S OF IT HAS SINCE DISSIPATED. A NEARLY STATIONARY MCS EXISTED NEAR
THE INTERSECTION OF KS-MO-OK AND IF ANY MOVEMENT IS EXPECTED OF
IT...IT SHOULD BE A SLOW ONE TO THE SE. FURTHER TO THE NW...A
WEAKENING COMPLEX OF TSRA WAS OVER THE MID MO VALLEY IN ERN NEBRASKA
MOVING E-SE WITH ANOTHER BATCH OF TSRA FURTHER TO THE W OVER THE HI
PLAINS OF WRN SD AND WRN NEBRASKA. THIS SEWD MOVEMENT OF SYSTEMS IS
COURTESY OF WEAK NW UPPER LEVEL FLOW THANKS TO THE UPPER LEVEL RIDGE
RETREATING TO THE SWRN CONUS. TEMPS AROUND THE AREA ARE IN THE LO
70S FOR MOST AREAS...WITH 60S IN THE FAR NRN FA.
THE MODELS TAKE THE FRONTAL BOUNDARY AND CONTINUE TO STALL IT IN ITS
CURRENT POSITION JUST N OF THE INTERSTATE 70 CORRIDOR THIS
MORNING...AND THEN RETREAT IT BACK TO THE N THIS AFTERNOON. IF THE
AIRMASS IS ANYTHING LIKE THE PAST COUPLE OF DAYS...IT WILL BE
EASIEST TO GENERATE TSRA ALG-S OF THE FRONT WHERE CINH WILL BE CLOSE
TO NIL AND ENOUGH LOCALLY GENERATED LO LEVEL CONVERGENCE AND/OR
SMALL UPPER LEVEL DISTURBANCES WILL PROVIDE ALL THE FOCUS NEEDED TO
GET TSRA GOING. TIMING-WISE...LOOK FOR NEW DEVELOPMENT FROM MIDDAY
ON WITH THE HEATING OF THE DAY AND REDUCTION OF CINH TO NEAR ZERO.
THE MORE ORGANIZED SYSTEM TO OUR SW IS NOT EXPECTED TO GET HERE
WHILE THE OTHER ORGANIZED SYSTEM TO OUR NW OVER NEBRASKA IS EXPECTED
TO WEAKEN AS IT MOVES INTO MORE STABLE AIR BEHIND THE SFC FRONT
ACROSS NE MO AND SE IA. HOWEVER...SOME MEASURE OF REORGANIZATION IS
EXPECTED FROM THE REMNANT MCV OF THIS SYSTEM AS IT SLIDES THRU SRN
IA TODAY BUT TIMING-WISE...PROBABLY WON/T HAVE MUCH OF A SAY IN THE
FCST FOR OUR AREA UNTIL LATE IN THE DAY IN NE MO. AND SO...HAVE
SLID POPS TODAY BACK TO HI-END CHC CATEGORY FROM LIKELYS EARLIER AS
THIS UPPER LEVEL SYSTEM FROM THE NW IS EXPECTED TO AFFECT OUR AREA
MORE SLOWLY THAN ORIGINALLY ANTICIPATED...WITH THE LIKELYS COMMUTED
FOR MOST AREAS TO TONIGHT WHEN THE UPPER LEVEL SYSTEM MOVES THRU.
VERY LITTLE CHANGE IN MAX TEMPS TODAY AND MIN TEMPS TONIGHT FROM
PREVIOUS FCST...WITH MOST LOCATIONS REMAINING IN THE 80S TODAY WITH
STL METRO AREA POSSIBLY REACHING 90F...AND MINS TONIGHT AROUND 70.
TES
.LONG TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 400 AM CDT SUN JUL 21 2013
NW UPPER LEVEL FLOW WILL PERSIST THRU THE PERIOD INTO NEXT WEEKEND.
THIS WILL ENSURE THE EXTREME HEAT WILL REMAIN AT BAY...OR IF IT DOES
INTRUDE IT WILL NOT LAST FOR LONG. AND UNTIL SFC FRONTAL BOUNDARIES
CAN MAKE A DECENT PUSH THRU...THIS SETUP ALSO STRONGLY ALLUDES TO A
CONTINUATION OF THE ACTIVE WX PATTERN THAT WE HAVE SEEN IN RECENT
DAYS WITH A THREAT FOR TSRA.
WE WILL EITHER BE IN A WARM SECTOR SETUP OR HAVE THE PRESENCE OF A
FRONT OVER OUR AREA THRU TUESDAY NIGHT...AND THUS WILL HAVE THE
LINGERING CHC FOR TSRA DURING THAT TIME. A CDFNT FINALLY LOOKS TO
PUSH THRU BY WEDNESDAY THEN SHUNTING THE BETTER RAIN CHCS TO THE S
AND SW AND PROVIDING A COUPLE OF MAINLY DRY DAYS WED AND THURS.
MODELS CONTINUE TO ZERO IN ON WHAT COULD BE A SIGNIFICANT WIDESPREAD
RAIN EVENT FOR LATE WEEK WITH APPROACH OF ANOTHER CDFNT AND WAVE OF
LO PRES ALONG THIS FRONT THANKS TO A STRONG MID LEVEL SHORTWAVE
TROF. TIMING RIGHT NOW LOOKS TO BE FROM LATE FRIDAY THRU EARLY
SATURDAY AND HAS BEEN FAIRLY CONSISTENT RUN-TO-RUN THE PAST COUPLE
OF DAYS.
A BRIEF RETURN OF THE HEAT AND HUMIDITY IS ANTICIPATED FOR MUCH OF
OUR AREA MONDAY AND TUESDAY AS THE FRONT RIDES TO THE N MONDAY THEN
DROPS S AGAIN LATE TUESDAY. AMBIENT TEMPS IN THE 90-95 RANGE SHOULD
YIELD HEAT INDEX VALUES AROUND 100 IN SPOTS...MAINLY STL METRO.
IF THE FRONT DOES MAKE A GOOD PUSH THRU ON WEDNESDAY...TEMPS WILL
STRUGGLE TO GET ABOVE 85 FOR THE REMAINDER OF THE PERIOD WITH A
REINFORCING SHOT OF COOLER AIR DUE ON EITHER FRIDAY OR SATURDAY.
TES
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1142 PM CDT SAT JUL 20 2013
LATEST CONVECTIVE TRENDS SHOW THAT CONVECTIVE CLUSTER EXTENDING
FROM SOUTH OF JEFFERSON CITY IS DEVELOPING NORTHWEST TOWARDS
SEDELIA MISSOURI AND WILL GRADUALLY MEET WITH DEVELOPING
CONVECTION OVER NORTHWEST MISSOURI. THE LATEST HRRR MESOSCALE
MODEL RUN SHOWS THE CONVECTIVE CLUSTER SOUTHWEST OF JEFFERSON CITY
HOWEVER THE LATEST RUN DOES NOT SHOW THE DEVELOPING CONVECTION
OVER NORTHWEST MISSOURI ATTM. THE AREA OF CONVECTION IS WTIHIN THE
AXIS OF HIGHEST MLCAPE WHICH EXTENDS NORTHWEST - SOUTHEAST ACROSS
NORTHWEST INTO SOUTH CENTRAL MISSOURI. CLUSTER OF THUNDERSTORMS
FROM SOUTHEAST SOUTH DAKOTA THROUGH CENTRAL NEBRASKA ASSOCIATED
WITH UPPER LEVEL DISTURBANCE OVER THE NORTHERN PLAINS. THIS
DISTURBANCE WILL MOVE EAST-SOUTHEAST ALONG THE MEAN NORTHWEST FLOW
AND BRING INCREASING THREAT TO SHOWERS AND THUNDERSTORMS OVER
CENTRAL MISSOURI BY ;ATE MORNING TO MID DAY AND MOVE INTO EASTERN
SECTIONS OF MISSOURI AND SOUTHWEST ILLINOIS BY NID TO LATE
AFTERNOON.
SPECIFICS FOR KSTL...WINDS WILL BE LIGHT AND VARIABLE THROUGH
DAYBREAK ON SUNDAY. THEN WINDS WILL BECOME SOUTHEAST AT 5 TO 8
KTS. ISOLATED SHOWERS ANDT HUNDERSTORMS ARE POSSIBLE BY LATE
MORNING FOR STL BUT HIGHER CHANCES INCREASE BY MID AFTERNOON.
CEILING WILL REMAIN AOA 10000 FT BUT LOWER CEILNGS ARE EXPECTED BY
EARLY TO MID AFTERNOON AS THUNDERSTORMS THREAT WILL INCREASE
DURING THE MID TO LATE AFTERNOON HOURS OVER STL. GUSTING SURFACE
WINDS UP TO 30 TO 35 KTS ARE POSSIBLE WITH THE STRONGER STORMS.
PRZYBYLINSKI
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
342 AM CDT SUN JUL 21 2013
.SHORT TERM...(THROUGH LATE TONIGHT)
ISSUED AT 342 AM CDT SUN JUL 21 2013
EARLY THIS MORNING...A STALLED OUT AND WEAKLY-DEFINED SFC FRONTAL
BOUNDARY EXISTED JUST N OF THE INTERSTATE 70 CORRIDOR. PCPN THAT
HAD DEVELOPED EARLIER IN THE NIGHT IN THE AIRMASS NEAR IT OR TO THE
S OF IT HAS SINCE DISSIPATED. A NEARLY STATIONARY MCS EXISTED NEAR
THE INTERSECTION OF KS-MO-OK AND IF ANY MOVEMENT IS EXPECTED OF
IT...IT SHOULD BE A SLOW ONE TO THE SE. FURTHER TO THE NW...A
WEAKENING COMPLEX OF TSRA WAS OVER THE MID MO VALLEY IN ERN NEBRASKA
MOVING E-SE WITH ANOTHER BATCH OF TSRA FURTHER TO THE W OVER THE HI
PLAINS OF WRN SD AND WRN NEBRASKA. THIS SEWD MOVEMENT OF SYSTEMS IS
COURTESY OF WEAK NW UPPER LEVEL FLOW THANKS TO THE UPPER LEVEL RIDGE
RETREATING TO THE SWRN CONUS. TEMPS AROUND THE AREA ARE IN THE LO
70S FOR MOST AREAS...WITH 60S IN THE FAR NRN FA.
THE MODELS TAKE THE FRONTAL BOUNDARY AND CONTINUE TO STALL IT IN ITS
CURRENT POSITION JUST N OF THE INTERSTATE 70 CORRIDOR THIS
MORNING...AND THEN RETREAT IT BACK TO THE N THIS AFTERNOON. IF THE
AIRMASS IS ANYTHING LIKE THE PAST COUPLE OF DAYS...IT WILL BE
EASIEST TO GENERATE TSRA ALG-S OF THE FRONT WHERE CINH WILL BE CLOSE
TO NIL AND ENOUGH LOCALLY GENERATED LO LEVEL CONVERGENCE AND/OR
SMALL UPPER LEVEL DISTURBANCES WILL PROVIDE ALL THE FOCUS NEEDED TO
GET TSRA GOING. TIMING-WISE...LOOK FOR NEW DEVELOPMENT FROM MIDDAY
ON WITH THE HEATING OF THE DAY AND REDUCTION OF CINH TO NEAR ZERO.
THE MORE ORGANIZED SYSTEM TO OUR SW IS NOT EXPECTED TO GET HERE
WHILE THE OTHER ORGANIZED SYSTEM TO OUR NW OVER NEBRASKA IS EXPECTED
TO WEAKEN AS IT MOVES INTO MORE STABLE AIR BEHIND THE SFC FRONT
ACROSS NE MO AND SE IA. HOWEVER...SOME MEASURE OF REORGANIZATION IS
EXPECTED FROM THE REMNANT MCV OF THIS SYSTEM AS IT SLIDES THRU SRN
IA TODAY BUT TIMING-WISE...PROBABLY WON/T HAVE MUCH OF A SAY IN THE
FCST FOR OUR AREA UNTIL LATE IN THE DAY IN NE MO. AND SO...HAVE
SLID POPS TODAY BACK TO HI-END CHC CATEGORY FROM LIKELYS EARLIER AS
THIS UPPER LEVEL SYSTEM FROM THE NW IS EXPECTED TO AFFECT OUR AREA
MORE SLOWLY THAN ORIGINALLY ANTICIPATED...WITH THE LIKELYS COMMUTED
FOR MOST AREAS TO TONIGHT WHEN THE UPPER LEVEL SYSTEM MOVES THRU.
VERY LITTLE CHANGE IN MAX TEMPS TODAY AND MIN TEMPS TONIGHT FROM
PREVIOUS FCST...WITH MOST LOCATIONS REMAINING IN THE 80S TODAY WITH
STL METRO AREA POSSIBLY REACHING 90F...AND MINS TONIGHT AROUND 70.
TES
.LONG TERM...(SUNDAY THROUGH NEXT SATURDAY)
ISSUED AT 252 PM CDT SAT JUL 20 2013
(SUNDAY THROUGH TUESDAY)
FOCUS THRU THE PERIOD CONTINUES TO BE PRECIP CHANCES.
MDLS ARE IN RELATIVELY GOOD AGREEMENT WITH RESPECT TO MASS FIELDS
AND IN GENERAL...HAVE A GENERAL CONSENSUS ON HOW THINGS WILL PAN
OUT THRU THIS PERIOD. THERE ARE SOME DIFFERENCES IN TIMING AS WELL
AS WHAT FEATURES WILL PRODUCE PRECIP AND WHICH MAY NOT.
OVERALL...HAVE TRENDED TWD A GFS/LOCAL WRF SOLN WHICH ARE IN BETTER
AGREEMENT THAN THE OTHER OPERATIONAL GUIDANCE.
NOT MUCH IN THE WAY OF CHANGES TO THE PREV FORECAST WRT POPS OR
TEMPS. LOWERED POPS ACROSS NRN PORTIONS OF THE CWA ON MON. THE S/W
IS NOW PROGD TO BE E OF THOSE AREAS BY MON MORNING...BUT WILL KEEP
LOW POPS FOR UNCERTAINTY IN TIMING.
(WEDNESDAY THROUGH SATURDAY)
NOT MUCH IN THE WAY OF CHANGES FROM THE PREV FORECAST THRU THIS
PERIOD. MDLS ARE IN GENERALLY GOOD AGREEMENT REGARDING MASS FIELDS.
EXPECT THIS PERIOD TO OVERALL BE COOLER WITH PRECIP CHANCES
CONTINUING THRU WED. THURS REMAINS DRY WITH THE SFC RIDGE SETTLED
OVER THE AREA. HOWEVER...MDLS TIMING THE NEXT S/W AND ASSOCIATED
PRECIP INTO THE AREA BY FRI AND REMAINING OVER PORTIONS OF THE CWA
INTO SAT. KEPT POPS ON THE LOWER SIDE DUE TO UNCERTAINTY IN TIMING
AND WILL INCREASE AS CONFIDENCE BUILDS AND TIME APPROACHES.
TILLY
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1142 PM CDT SAT JUL 20 2013
LATEST CONVECTIVE TRENDS SHOW THAT CONVECTIVE CLUSTER EXTENDING
FROM SOUTH OF JEFFERSON CITY IS DEVELOPING NORTHWEST TOWARDS
SEDELIA MISSOURI AND WILL GRADUALLY MEET WITH DEVELOPING
CONVECTION OVER NORTHWEST MISSOURI. THE LATEST HRRR MESOSCALE
MODEL RUN SHOWS THE CONVECTIVE CLUSTER SOUTHWEST OF JEFFERSON CITY
HOWEVER THE LATEST RUN DOES NOT SHOW THE DEVELOPING CONVECTION
OVER NORTHWEST MISSOURI ATTM. THE AREA OF CONVECTION IS WTIHIN THE
AXIS OF HIGHEST MLCAPE WHICH EXTENDS NORTHWEST - SOUTHEAST ACROSS
NORTHWEST INTO SOUTH CENTRAL MISSOURI. CLUSTER OF THUNDERSTORMS
FROM SOUTHEAST SOUTH DAKOTA THROUGH CENTRAL NEBRASKA ASSOCIATED
WITH UPPER LEVEL DISTURBANCE OVER THE NORTHERN PLAINS. THIS
DISTURBANCE WILL MOVE EAST-SOUTHEAST ALONG THE MEAN NORTHWEST FLOW
AND BRING INCREASING THREAT TO SHOWERS AND THUNDERSTORMS OVER
CENTRAL MISSOURI BY ;ATE MORNING TO MID DAY AND MOVE INTO EASTERN
SECTIONS OF MISSOURI AND SOUTHWEST ILLINOIS BY NID TO LATE
AFTERNOON.
SPECIFICS FOR KSTL...WINDS WILL BE LIGHT AND VARIABLE THROUGH
DAYBREAK ON SUNDAY. THEN WINDS WILL BECOME SOUTHEAST AT 5 TO 8
KTS. ISOLATED SHOWERS ANDT HUNDERSTORMS ARE POSSIBLE BY LATE
MORNING FOR STL BUT HIGHER CHANCES INCREASE BY MID AFTERNOON.
CEILING WILL REMAIN AOA 10000 FT BUT LOWER CEILNGS ARE EXPECTED BY
EARLY TO MID AFTERNOON AS THUNDERSTORMS THREAT WILL INCREASE
DURING THE MID TO LATE AFTERNOON HOURS OVER STL. GUSTING SURFACE
WINDS UP TO 30 TO 35 KTS ARE POSSIBLE WITH THE STRONGER STORMS.
PRZYBYLINSKI
&&
.PRELIMINARY POINT TEMPS/POPS...
SAINT LOUIS 88 73 93 75 / 50 60 40 40
QUINCY 86 70 90 72 / 50 60 20 30
COLUMBIA 85 70 92 72 / 60 60 30 50
JEFFERSON CITY 86 71 92 72 / 60 60 30 50
SALEM 87 72 88 71 / 50 50 40 30
FARMINGTON 85 70 91 72 / 50 50 50 50
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1202 AM CDT SUN JUL 21 2013
.UPDATE...
ISSUED AT 937 PM CDT SAT JUL 20 2013
ISSUED AT 926 PM CDT SAT JUL 20 2013
DIURNAL CONVECTION AIDED BY A PLETHORA OF OUTFLOW BOUNDARIES AND A
WEAK COLD FRONT HAS REALLY BECOME LIMITED TO JUST A FEW STORMS
FROM THE LAKE OF THE OZARKS TO SULLIVAN MISSOURI. SHOULD SEE THIS
CONVECTION CONTINUE TO SLOWLY DISSIPATE AS IT SQUEEZES OUT THE
LAST OF THE SURFACE INSTABILITY. NEXT ROUND OF CONVECTION IS
LIKELY TO DEVELOP FURTHER NORTHWEST...AS NORTHWEST MISSOURI
REMAINS QUITE UNSTABLE WITH SPC MESOSCALE ANALYSIS SHOWING UPWARDS
OF 4000 J/KG OF MUCAPE. APPROACHING SHORTWAVE FROM THE UPPER
PLAINS SHOULD CAUSE THE LOW LEVEL JET TO INCREASE AND ACT UPON
THIS INSTABILITY WITH THUNDERSTORMS INCREASING AFTER
MIDNIGHT/SUNDAY MORNING.
CVKING
&&
.SHORT TERM...(THROUGH LATE TONIGHT)
ISSUED AT 319 PM CDT SAT JUL 20 2013
THE WEST-EAST ORIENTED SURFACE COLD FRONT IS MEANDERING SOUTHWARD
AND EXTENDED FROM JUST SOUTH OF KANSAS CITY TO JUST NORTH OF
COLUMBIA AND ST LOUIS TO LITCHFIELD AT 20Z. SCATTERED THUNDERSTORMS
HAVE DEVELOPED WITHIN THE LAST HOUR OR SO FROM JUST NORTH OF ST
LOUIS INTO CENTRAL IL ALONG THE FRONT...BUT THE GREATEST COVERAGE OF
STORMS IS ACROSS SOUTHEAST AND SOUTH CENTRAL MISSOURI ALONG AND
AHEAD OF A WEAK SURFACE TROF/CONVERGENCE ZONE WHERE THE ATMOSPHERE
IS VERY UNSTABLE. THESE SHOULD GENERALLY REMAIN THE FAVORED AREAS
THRU SUNSET...AHEAD OF THE VERY SLOW MOVING FRONT AND CONVERGENCE
ZONE. ALL OF THIS ACTIVITY WILL BE SLOW MOVING GIVEN WEAK FLOW AND
SHEAR ALOFT BUT THE GENERAL TENDENCY SHOULD BE FOR AN OVERALL SEWD
MOTION...ESPECIALLY WHERE MERGERS CAN LEAD TO GREATER ORGANIZATION.
THE DECREASE IN INSTABILITY WITH SUNSET SHOULD RESULT IN LARGE
DECREASE IN COVERAGE. THEN THE MAIN THREAT OF SHOWERS/STORMS FOR THE
REMAINDER OF THE NIGHT WILL BE ALONG AND SOUTH OF THE FRONT WHICH
WILL BECOME STATIONARY FROM SOUTHWEST ILLINOIS THRU MID MO INTO NRN
KS.
GLASS
.LONG TERM...(SUNDAY THROUGH NEXT SATURDAY)
ISSUED AT 252 PM CDT SAT JUL 20 2013
(SUNDAY THROUGH TUESDAY)
FOCUS THRU THE PERIOD CONTINUES TO BE PRECIP CHANCES.
MDLS ARE IN RELATIVELY GOOD AGREEMENT WITH RESPECT TO MASS FIELDS
AND IN GENERAL...HAVE A GENERAL CONSENSUS ON HOW THINGS WILL PAN
OUT THRU THIS PERIOD. THERE ARE SOME DIFFERENCES IN TIMING AS WELL
AS WHAT FEATURES WILL PRODUCE PRECIP AND WHICH MAY NOT.
OVERALL...HAVE TRENDED TWD A GFS/LOCAL WRF SOLN WHICH ARE IN BETTER
AGREEMENT THAN THE OTHER OPERATIONAL GUIDANCE.
NOT MUCH IN THE WAY OF CHANGES TO THE PREV FORECAST WRT POPS OR
TEMPS. LOWERED POPS ACROSS NRN PORTIONS OF THE CWA ON MON. THE S/W
IS NOW PROGD TO BE E OF THOSE AREAS BY MON MORNING...BUT WILL KEEP
LOW POPS FOR UNCERTAINTY IN TIMING.
(WEDNESDAY THROUGH SATURDAY)
NOT MUCH IN THE WAY OF CHANGES FROM THE PREV FORECAST THRU THIS
PERIOD. MDLS ARE IN GENERALLY GOOD AGREEMENT REGARDING MASS FIELDS.
EXPECT THIS PERIOD TO OVERALL BE COOLER WITH PRECIP CHANCES
CONTINUING THRU WED. THURS REMAINS DRY WITH THE SFC RIDGE SETTLED
OVER THE AREA. HOWEVER...MDLS TIMING THE NEXT S/W AND ASSOCIATED
PRECIP INTO THE AREA BY FRI AND REMAINING OVER PORTIONS OF THE CWA
INTO SAT. KEPT POPS ON THE LOWER SIDE DUE TO UNCERTAINTY IN TIMING
AND WILL INCREASE AS CONFIDENCE BUILDS AND TIME APPROACHES.
TILLY
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1142 PM CDT SAT JUL 20 2013
LATEST CONVECTIVE TRENDS SHOW THAT CONVECTIVE CLUSTER EXTENDING
FROM SOUTH OF JEFFERSON CITY IS DEVELOPING NORTHWEST TOWARDS
SEDELIA MISSOURI AND WILL GRADUALLY MEET WITH DEVELOPING
CONVECTION OVER NORTHWEST MISSOURI. THE LATEST HRRR MESOSCALE
MODEL RUN SHOWS THE CONVECTIVE CLUSTER SOUTHWEST OF JEFFERSON CITY
HOWEVER THE LATEST RUN DOES NOT SHOW THE DEVELOPING CONVECTION
OVER NORTHWEST MISSOURI ATTM. THE AREA OF CONVECTION IS WTIHIN THE
AXIS OF HIGHEST MLCAPE WHICH EXTENDS NORTHWEST - SOUTHEAST ACROSS
NORTHWEST INTO SOUTH CENTRAL MISSOURI. CLUSTER OF THUNDERSTORMS
FROM SOUTHEAST SOUTH DAKOTA THROUGH CENTRAL NEBRASKA ASSOCIATED
WITH UPPER LEVEL DISTURBANCE OVER THE NORTHERN PLAINS. THIS
DISTURBANCE WILL MOVE EAST-SOUTHEAST ALONG THE MEAN NORTHWEST FLOW
AND BRING INCREASING THREAT TO SHOWERS AND THUNDERSTORMS OVER
CENTRAL MISSOURI BY ;ATE MORNING TO MID DAY AND MOVE INTO EASTERN
SECTIONS OF MISSOURI AND SOUTHWEST ILLINOIS BY NID TO LATE
AFTERNOON.
SPECIFICS FOR KSTL...WINDS WILL BE LIGHT AND VARIABLE THROUGH
DAYBREAK ON SUNDAY. THEN WINDS WILL BECOME SOUTHEAST AT 5 TO 8
KTS. ISOLATED SHOWERS ANDT HUNDERSTORMS ARE POSSIBLE BY LATE
MORNING FOR STL BUT HIGHER CHANCES INCREASE BY MID AFTERNOON.
CEILING WILL REMAIN AOA 10000 FT BUT LOWER CEILNGS ARE EXPECTED BY
EARLY TO MID AFTERNOON AS THUNDERSTORMS THREAT WILL INCREASE
DURING THE MID TO LATE AFTERNOON HOURS OVER STL. GUSTING SURFACE
WINDS UP TO 30 TO 35 KTS ARE POSSIBLE WITH THE STRONGER STORMS.
PRZYBYLINSKI
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
301 AM CDT SUN JUL 21 2013
.DISCUSSION...
FORECASTING AREAL EXTENT OF CONVECTION THROUGH THE FORECAST WILL
BE A SIGNIFICANT CHALLENGE AS THE REGION REMAINS IN NORTHWEST FLOW
THIS WEEK.
FIRST ROUND OF CONVECTION IS MOVING INTO EASTERN NEBRASKA EARLY
THIS MORNING...BUT WILL ALSO HAVE TO OVERCOME A POCKET OF DRY AIR
AT H85. CONTINUED THETAE ADVECTION SHOULD HELP TO ERODE THIS DRY
POCKET AND CONTINUE TRIGGER STORMS THIS MORNING THAT WILL
CONTINUE TO MOVE EASTWARD THROUGH THE AREA INTO WESTERN IOWA
BEFORE DISSIPATING THROUGH MID TO LATE MORNING. WHILE HEAVY RAINS
ARE NOT WIDESPREAD...SOME VERY SPOTTY LOCATIONS WHERE LIGHTNING IS
OCCURRING ARE LIKELY PICKING UP SOME DECENT MEANINGFUL RAINFALL.
MEANWHILE...WATER VAPOR IMAGERY INDICATES ANOTHER SUBTLE WAVE IS
LIKELY MOVING THROUGH WESTERN SOUTH DAKOTA. ANOTHER CLUSTER OF
STORMS HAS REFIRED ACROSS THAT AREA...MOVING INTO NORTH CENTRAL
NEBRASKA. BOTH THE NAM AND RAP SEEM TO HAVE PICKED UP ON THIS
FEATURE AND MOVE IT THROUGH THE FORECAST AREA THIS AFTERNOON...WHICH
COULD BE THE TRIGGER FOR ADDITIONAL STORMS AS WE HEAD THROUGH PEAK
HEATING. FORWARD SPEED SUGGESTS THAT THIS MAY MOSTLY BE OUT OF THE
AREA BY EARLY THIS EVENING.
THE REMAINDER OF SUNDAY NIGHT AND MONDAY MORNING SHOULD BE DRY. A
FRONTAL BOUNDARY MOVING INTO THE REGION COULD TRIGGER ISOLATED
AFTERNOON STORMS IN NORTHEAST NEBRASKA. TEMPS AHEAD OF THE FRONT
WILL PROBABLY REACH THE LOWER 90S ONCE AGAIN. SHOULD ALSO SEE A
CHANCE OF THUNDERSTORMS MONDAY NIGHT AS THE FRONT MOVES THROUGH
THE AREA.
THE NEXT WAVE APPEARS ON THE HORIZON BY TUESDAY AFTERNOON THEN
MOVES THROUGH THE REGION TUESDAY NIGHT. WEDNESDAY AND WEDNESDAY
NIGHT SHOULD BE DRY...BUT ANOTHER WAVE MOVES INTO THE AREA ON
THURSDAY AND LINGERS THROUGH FRIDAY. THE GFS SUGGESTS THAT WE
MIGHT REMAIN DRY ON SATURDAY...BUT THE ECMWF HAS YET ANOTHER SURGE
OF MOISTURE MOVING THROUGH. NEVERTHELESS...CONFIDENCE DECREASES IN
SPECIFICS TOWARD THE END OF THE WEEK.
DEWALD
&&
.AVIATION...06Z TAFS FOR KOMA...KLNK...AND KOFK. FORECAST
CONCERNS THROUGH THE PERIOD WILL BE CONVECTIVE CHANCES AND WHEN TO
INCLUDE IN THE TAF. CONVECTION IS ONGOING ACROSS PARTS OF SOUTH
DAKOTA AND WESTERN NEBRASKA AND IS ASSOCIATED WITH A SHORTWAVE
TROF MOVING SOUTHEAST ACROSS THE DAKOTAS AND NEBRASKA THROUGH
SUNDAY. THE LOW LEVEL JET WILL ALSO INCREASE OVER MISSOURI AND THE
SHOULD AID IN NEW DEVELOPMENT FARTHER SOUTH AND WITH DEEPER
MOISTURE RETURNING COULD SEE RE-DEVELOPMENT DURING THE DAY. SHOULD
SEE SOME SHOWERS...HOWEVER DUE TO TSRA BEING ISOLD WILL ONLY
MENTION SPARINGLY. COULD SEE SOME GUSTY WINDS NEAR SHOWERS/STORMS...
OTHERWISE WINDS WILL GENERALLY BE FROM THE SOUTHEAST
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
113 AM CDT SUN JUL 21 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.
&&
.UPDATE...
ISSUED AT 111 AM CDT SUN JUL 21 2013
REDUCED CLOUD COVER WITH CLEARING SKIES SUBSIDENCE OVER WESTERN
NEBRASKA. THUNDERSTORM CHANCES DROPPED INTO ISOLATED CATEGORIES
AND QPF FIELDS DRASTICALLY REDUCED.
&&
.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 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 111 AM CDT SUN JUL 21 2013
THUNDERSTORMS OVER SOUTH CENTRAL SOUTH DAKOTA HAVE PUT TEMPO GROUP
IN KVTN TAF EARLY THIS MORNING. WITH UNCERTAINTY IN FORECAST HAVE
LEFT THUNDERSTORMS OUT OF TAF FOR SUNDAY AFTERNOON. VFR CONDITIONS
OVER WESTERN NEBRASKA EARLY THIS MORNING WITH CLEARING SKIES
BEHIND THUNDERSTORMS MOVING INTO CENTRAL NEBRASKA.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...POWER
SYNOPSIS...CLB
SHORT TERM...SPRINGER
LONG TERM...CLB
AVIATION...POWER
AREA FORECAST DISCUSSION
NWS HASTINGS NE
111 AM CDT SUN JUL 21 2013
.UPDATE...
ISSUED AT 942 PM CDT SAT JUL 20 2013
AS WAS THE CASE DURING THE PRECEDING DAY SHIFT...CONFIDENCE IN
THUNDERSTORM TRENDS/RAIN CHANCES THROUGH THE OVERNIGHT HOURS
CONTINUES TO RUN AT LESS-THAN-IDEAL LEVELS. FOR AT LEAST A SHORT
TIME LONGER...THE ENTIRE CWA CONTINUES IN A MULTI-HOUR LULL IN THE
WAKE OF AFTERNOON CONVECTION THAT HAS SINCE EXITED WELL SOUTHEAST
OF THE CWA. ALTHOUGH AREAS FROM THE TRI-CITIES AND WEST/NORTHWEST
ESSENTIALLY MISSED OUT ON THE EARLIER ROUND...SEVERAL SMALL
POCKETS ACROSS NORTH CENTRAL KS AND FAR SOUTHERN NEB RECEIVED A
QUICK 1-4 INCH DRENCHING PER OUR LOCAL STORM REPORTS. LOOKING
AHEAD...THE ONLY SHOW IN TOWN AT THE 9 PM HOUR IS A SMALL LINEAR
COMPLEX OF STRONG TO MARGINALLY SEVERE STORMS TRACKING SOUTH-
SOUTHEAST THROUGH THE WEST CENTRAL/NORTH CENTRAL NEB
SANDHILLS...BUT GRADUALLY APPROACHING THE FRINGES OF THE CWA.
FARTHER UPSTREAM...ADDITIONAL CLUSTERS OF STRONG-SEVERE STORMS
HAVE TAKEN OFF IN SOUTHERN SD.
ON THE LARGE SCALE ALOFT...SEASONABLY DECENT WEST-NORTHWEST FLOW
WILL PERSIST THROUGH THE NIGHT MAINLY AT/ABOVE 500
MILLIBARS...WHILE FAIRLY CHAOTIC AND LIGHT FLOW PERSISTS A BIT
LOWER AT 700MB...AND LOWER YET EVEN THE FLOW AT 850MB APPEARS
QUITE UNDERWHELMING...WITH THE PRIMARY EXIT REGION OF A FAIRLY
WEAK LOW LEVEL JET AIMED NORTH OF THE LOCAL AREA NEAR THE NEB/SD
BORDER. AS A RESULT...GIVEN THE LACK OF NOTABLE THETA-E
ADVECTION/CONVERGENCE IN AND NEAR THE CWA AT BOTH THE 850/700MB
LEVEL...OUR CURRENTLY-ADVERTISED 50+ PERCENT POPS ACROSS THE
MAJORITY OF THE CWA OVERNIGHT ARE COMING INCREASINGLY UNDER
QUESTION ESPECIALLY IN THE CENTRAL/SOUTHEAST COUNTIES. NOT
SURPRISINGLY...THE LATEST 00Z NAM AND HRRR ARE BOTH PRETTY PALTRY
WITH MEASURABLE RAIN POTENTIAL OVERNIGHT. BASED ON CURRENT RADAR
TRENDS...IT MAY VERY WELL END UP BEING THE CASE THAT THE BEST HOPE
FOR LEGITIMATE RAINFALL WILL HINGE ON HOW SUCCESSFULLY THE
ACTIVITY CURRENTLY DRIFTING TOWARD THE FAR NORTHWEST EDGES OF THE
CWA HOLDS TOGETHER OVER THE NEXT FEW HOURS. PER THE LATEST RAP
INSTABILITY TRENDS...THERE COULD BE AT LEAST A MODEST INCREASE IN
ELEVATED MUCAPE IN THE 850-700MB LAYER INTO THE 500-1000 J/KG
RANGE AS THE NIGHT WEARS ON...BUT MODEL SOUNDINGS SHOW THAT EVEN
MUCH OF THIS INSTABILITY MAY BE RATHER CAPPED. AS FOR ANY
OVERNIGHT SEVERE THREAT...THAT ALSO APPEARS TO BE ON A
DECLINE...UNLESS SOMEHOW THE CONVECTION CURRENTLY IN THE NORTH
PLATTE CWA RE-INTENSIFIES OR DEVELOPS A NEW VIGOROUS COLD POOL
OVER THE NEXT FEW HOURS. HAIL-WISE...IT MAY BE TOUGH TO GET
ANYTHING LARGER THAN DIMES-NICKELS GIVEN LATEST INSTABILITY
TRENDS.
IN SUMMARY...WILL CONTINUE TO EXAMINE THE LATEST TRENDS AND
POTENTIALLY DECREASE POPS ACROSS PARTS OF THE CWA IN A FORTHCOMING
EVENING UPDATE...BUT IN THE CONTINUED PRESENCE OF SUBTLE
NORTHWEST-FLOW FORCING...PROBABLY CANNOT EXCLUDE ANY LOCATION FROM
AT LEAST A TOKEN 20 PERCENT CHANCE OF SHOWERS/STORMS
OVERNIGHT...AS NORTHWEST FLOW IS NOTORIOUS FOR PROVIDING A FEW
SURPRISES. BY AND LARGE THOUGH...ITS STARTING TO LOOK LIKE THE 50+
POPS WE/VE BEEN ADVERTISING THE PAST FEW DAYS MAY PROVE OVERDONE
FOR A DECENT CHUNK OF THE AREA...ESPECIALLY FOR THOSE LOOKING FOR
MORE THAN A FEW TENTHS OF AN INCH. ALSO MAY BE MAKING A FEW
DOWNWARD TWEAKS TO OVERNIGHT LOW TEMPS BASED ON LATEST
OBSERVATIONAL TRENDS AND GUIDANCE. WILL BE DEFER TO ONCOMING
OVERNIGHT SHIFT TO MAKE CHANGES BEYOND 12Z SUNDAY MORNING...BUT IT
APPEARS IT COULD BE ANOTHER DAY/NIGHT OF FICKLE THUNDERSTORM
TRENDS. LOOK FOR NEXT ROUND OF FORECAST UPDATES TO BE OUT BETWEEN
10-1030 PM...
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 353 PM CDT SAT JUL 20 2013
ALOFT: QUASI-ZONAL WNW FLOW WILL CONT THRU 00Z/MON. WV IMAGERY SHOWS
A SUBTLE SHRTWV TROF MOVING INTO THE PANHANDLE FROM WY. THIS TROF IS
FCST TO DEEPEN TNGT...CROSS THE FCST AREA SUN MRNG...AND WILL BE
MOVING INTO NERN KS DURING PEAK HEATING. WHILE THIS TROF MAY AID
TSTM DEVELOPMENT TNGT...HAVE TO WONDER IF SUBSIDENCE IN ITS WAKE
WILL CAP OFF TSTM THREAT SUN AFTN.
SFC: NUMEROUS OUTFLOW BOUNDARIES WILL LINGER THRU SUN. THE LEE/HEAT
LOW WILL STRENGTHEN AND DRIFT INTO WRN KS. THIS SHOULD DROP DWPTS
SUBSTANTIALLY FROM MCK-PHG-RCP AND PROBABLY DID NOT GO LOW ENOUGH.
RAINFALL: PLEASE FOLLOW OUR LOCAL STORM REPORTS /LSR/. WE HAVE
SEEN SOME SUBSTANTIAL 2-3 INCH AMTS BUT IT HAS BEEN FEAST OR
FAMINE.
REST OF THIS AFTN: THE ATMS HAS APPARENTLY STABILIZED OVER MUCH OF
S-CNTRL NEB BASED ON THE LACK OF CU AND A WWD MOVING OUTFLOW
BOUNDARY W OF HWY 283. SCT TSTMS WILL GRADUALLY DIE OFF OVER N-CNTRL
KS.
TNGT: PROBABLY SOMEWHAT OF A BREAK THIS EVNG. WE WERE WATCHING
UPSTREAM TSTMS OVER THE PANHANDLE...WHICH THE MODELS SUGGESTED WOULD
PROPAGATE INTO S-CNTRL NEB. THOSE TSTMS HAVE DIED WHICH LOWERS
CONFIDENCE IN TNGT/S FCST...ESPECIALLY SINCE VIS SATPIX SHOW NO
AGITATED CU FIELDS.
SOME SEMBLANCE OF A COUPLED ULJ DEVELOPS TNGT...WHICH WILL ENHANCE
THE LLJ. SO THE ENVIRONMENT WILL REMAIN FAVORABLE FOR ADDITIONAL
TSTM DEVELOPMENT.
SUN: IT ALL HINGES ON WHAT HAPPENS TNGT. IF SCT TSTMS FORM AND MOVE
THRU THEN WE/LL SEE TSTMS DEPARTING DURING THE MRNG HRS WITH
CLEARING THEREAFTER.
FCST SOUNDINGS INDICATE DAYTIME HEATING SHOULD ERODE THE CAP.
LEFTOVER OUTFLOW BOUNDARIES WILL PROVIDE FOCI FOR TSTM DEVELOPMENT.
HOWEVER...IT APPEARS DOUBTFUL WE SEE ANYTHING MORE THAN AN ISOLATED
TSTM MAYBE TWO? LARGE-SCALE SUBSIDENCE COULD LIMIT OR MITIGATE THE
THREAT ALTOGETHER. IT/S POSSIBLE MODEL SOUNDINGS ARE NOT FULLY
DEPICTING THIS. QPF IS PRETTY MEAGER SO IT MAY BE OF LITTLE
CONSEQUENCE.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 353 PM CDT SAT JUL 20 2013
GUIDANCE SUGGESTS NORTHWESTERLY MID TO UPPER LEVEL FLOW WILL PERSIST
OVER THE CENTRAL PLAINS THROUGH MUCH OF THE EXTENDED FORECAST
PERIOD. THERE WILL BE THE POTENTIAL FOR MULTIPLE SMALL SCALE
PERTURBATIONS TO WORK THEIR WAY ACROSS THE REGION AS A RESULT...WITH
QPF FIELDS FROM THE NAM...OPERATIONAL GFS...EC AND SREF-MEAN
SUGGESTING PRECIPITATION WILL BE REALIZED OVER VARIOUS PORTIONS OF
OUR AREA DURING THE EXTENDED FORECAST PERIOD. AN EVEN AVERAGE OF THE
NAM...OPERATIONAL GFS...EC...AND SREF-MEAN WAS UTILIZED TO DERIVE
QPF FIELDS AND RESULTANT POPS FOR MONDAY AND TUESDAY...WHICH RESULTS
IN LOW POPS BEING PRESENTED TO MOST ALL OF THE CWA BOTH DAYS. THE
SAME PATTERN IS EXPECTED TO PERSIST THROUGH MUCH OF THE REST OF THE
WEEK AS WELL...WITH ALLBLEND PROVIDING 20-60% POPS TO THE CWA AS A
RESULT. THESE POPS WERE LEFT UNCHANGED FOR THE MOST PART.
AS FOR SEVERE WEATHER CHANCES DURING THE EXTENDED FORECAST
PERIOD...PERSISTENT LOW LEVEL MOISTURE SHOULD PRESENT DECENT CAPE
VALUES ACROSS THE AREA...WITH GUIDANCE SUGGESTING SUCH VALUES WILL
AVERAGE FROM 1500 TO 3000J/KG ON MOST DAYS. GIVEN THE UNCERTAINTY OF
PLACEMENT AND TIMING OF SEVERE WEATHER HOWEVER...WILL PROVIDE A
VAGUE SEVERE WEATHER MENTION IN THE HWO FOR MONDAY BUT LEAVE OUT ANY
MENTION OF SEVERE WEATHER THROUGH THE REMAINDER OF THE EXTENDED
FORECAST PERIOD.
LITTLE CHANGE IN THE LOW LEVEL AIRMASS SHOULD PRESENT AFTERNOON HIGH
TEMPERATURES IN THE 90S TO START THE EXTENDED FORECAST PERIOD...WITH
SLIGHTLY COOLER AIR PROVIDING AFTERNOON HIGHS IN THE 80S TO NEAR 90
BY THE END OF THE EXTENDED FORECAST PERIOD. OVERNIGHT LOW
TEMPERATURES IN THE 60S ARE EXPECTED FOR MOST PART DURING THE
EXTENDED FORECAST PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 102 AM CDT SUN JUL 21 2013
A LINE OF SHOWERS AND THUNDERSTORMS NORTH AND WEST OF GRAND ISLAND
WILL SLIDE SOUTHEAST THROUGH KGRI OVER THE NEXT SEVERAL HOURS.
THESE THUNDERSTORMS HAVE WEAKENED SOME OVER THE LAST HOUR AND ARE
NON SEVERE. ODDS ARE GOOD THAT ANY PRECIPITATION WILL HAVE EXITED
KGRI PRIOR TO DAWN. THE WIND WILL GENERALLY BE LIGHT AND VARIABLE
TONIGHT...BUT COULD GUST TO AROUND 30 MPH IN AND AROUND
THUNDERSTORMS. A SLIGHT CHANCE OF THUNDERSTORMS WILL CONTINUE INTO
THE DAY ON SUNDAY...BUT THE CHANCE IS TOO LOW TO WARRANT INCLUSION
IN THE TAF. THE PREDOMINATE WIND DIRECTION ON SUNDAY SHOULD BE
SOUTHEAST.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...PFANNKUCH
SHORT TERM...HALBLAUB
LONG TERM...BRYANT
AVIATION...WESELY
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1133 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 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1129 PM CDT SAT JUL 20 2013
THE SCATTERED/NUMEROUS THUNDERSTORM ACTIVITY ACROSS SCNTL AND
NCNTL NEB SHOULD EXIT THE FCST AREA AROUND 06Z. OTHER ISOLATED
TSTM ACTIVITY ACROSS NRN NEB COULD CONTINUE OVERNIGHT. THE MODELS
SUGGEST THIS ACTIVITY WILL MOVE EAST.
OTHERWISE VFR IS EXPECTED THROUGH 20Z. THEREAFTER...SCATTERED
TSTMS SHOULD REDEVELOP ACROSS WRN AND NCNTL NEB. STORM MOTION WILL
BE EAST AND SOUTHEAST.
THE RISK TO THE FCST IS THAT THE MODELS ARE TOO FAST SUNDAY. THUS
ITS POSSIBLE THAT STORM DEVELOPMENT SUNDAY AFTN COULD HOLD OFF
UNTIL 22Z-23Z.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CLB
SHORT TERM...SPRINGER
LONG TERM...CLB
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
351 AM EDT SUN JUL 21 2013
.SYNOPSIS...
A TYPICAL SUMMER PATTERN OF HIGH PRESSURE OFFSHORE AND A TROUGH
OF LOW PRESSURE INLAND WILL PERSIST THROUGH TUESDAY. A COLD
FRONT WILL APPROACH FROM THE NORTHWEST WEDNESDAY THEN STALL OVER
THE REGION THURSDAY AND FRIDAY BEFORE MOVING OFFSHORE SATURDAY.
&&
.NEAR TERM /TODAY/...
AS OF 335 AM SUNDAY...A FEW PATCHY SHOWERS ARE AFFECTING THE
CENTRAL PAMLICO SOUND AND CENTRAL OUTER BANKS REGION AND A COUPLE
OF STRAY SHOWERS ARE MOVING OFF OF CORE BANKS EARLY THIS MORNING.
THE 3 KM HRRR MODEL HAS HAD THE BEST DEPICTION OF THE
PRECIPITATION PLACEMENT THIS MORNING AND WILL FOLLOW ITS TREND
THROUGH THE MIDDAY HOURS. THERE WILL BE A LULL IN THE ACTIVITY
THROUGH ABOUT MID-MORNING WHEN SOME ADDITIONAL SHOWERS MAY SCRAPE
THE SOUTHERN COAST. MORE WIDESPREAD PRECIPITATION MOVES INTO THE
SOUTHERN COASTAL PLAINS BY 18Z OR SO WITH HIGH CHANCE POPS OVER
THE COASTAL PLAINS...TAPERING BACK TO CHC NEAR THE COAST. WITH
PRECIPITABLE WATER VALUES BACK NEAR 2 INCHES...ANY SHOWERS THAT
DEVELOP COULD PRODUCE A QUICK DOWNPOUR OF UP TO AN INCH OR SO.
GIVEN MORE CLOUD COVER THAN RECENT DAYS...MAXIMUM TEMPERATURES
SHOULD REMAIN IN THE UPPER 80S FAIRLY UNIFORM IN THE MIDDLE TO
UPPER 80S AREA-WIDE.
&&
.SHORT TERM /TONIGHT/...
AS OF 345 AM SUNDAY...BOTH THE GFS AND NAM SHOW SOME STRONG MID-
LEVEL VORTICITY RIDING UP THE COAST TONIGHT...COUPLED WITH A WEAK
UPPER LEVEL TROUGH SLIDING ACROSS THE REGION. THIS ALONG WITH A
VERY MOIST ATMOSPHERE WILL LEAD TO A CHANCE OF SHOWERS/TSTMS
LINGERING THROUGH THE NIGHT. GIVEN THE TREND FROM THE LAST FEW
NIGHTS...HAVE TRENDED THE BEST PRECIPITATION CHANCES NEAR THE
COAST...WITH LITTLE ACTIVITY INLAND AFTER MIDNIGHT. OVERNIGHT LOWS
TONIGHT SHOULD BE IN THE 73 TO 77 DEGREE RANGE.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
AS OF 315 AM SUN...AN UPPER TROUGH OVER THE GREAT LAKES WILL DIG
SOUTH MON/TUES AND PERSIST OVER THE EASTERN CONUS THROUGH THE LONG
TERM...REINFORCING THE RAIN CHANCES THROUGH THE PERIOD. WEAK
PERTURBATIONS IN THE MID AND UPPER LEVELS WILL ALSO AID IN
DEVELOPING SHOWERS/TSTORMS DURING THE EXTENDED PERIOD...ESPECIALLY
DURING PEAK HEATING HOURS OF THE DAY. AT THE SURFACE...LONG FETCH SW
FLOW WILL TAP TROPICAL MOISTURE FROM THE GULF OF MEXICO AND WESTERN
ATLANTIC MON AND TUES...INCREASING PWATS TO AROUND 2 INCHES. A
WEAK COLD FRONT WILL APPROACH FROM THE NW MON INTO TUES...WHICH
WILL DISSIPATE WEST OF THE REGION PRIOR TO ANOTHER COLD FRONT
APPROACHING FROM THE NW WED INTO THURS. WITH DECENT MODEL
AGREEMENT THROUGH THE EXTENDED...HAVE INDICATED A WEAK FRONTAL
PASSAGE THURS NIGHT WITH BRIEF NORTHERLY FLOW/CAA ON FRI BEFORE
OFFSHORE RIDGE KICKS IN A SW FLOW AGAIN TAKES OVER.
HAVE CONTINUED THE TREND OF DIURNAL CONVECTION EACH DAY THROUGH
THURS WITH 40 TO 50 PERCENT POPS INLAND DURING THE AFTERNOON AND
25-30 PERCENT POPS OVERNIGHT. TRIED TO ADJUST TIMING OF POPS MON
AFTERNOON THROUGH TUES NIGHT TO ALSO COINCIDE WITH THE LOCATION OF
SEVERAL SHORTWAVE VORTMAX ALOFT THAT ROTATE AROUND THE BASE OF
THE BROAD UPPER TROUGH. 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. POPS THURS NIGHT
THROUGH FRI NIGHT REMAIN PINNED NEAR THE COAST WITH SCATTERED
CONVECTION POSSIBLE AGAIN SAT AFTERNOON AS LIGHT SE/S FLOW RETURNS
TO THE AREA. TEMPS THROUGH THE LONG TERM PERIOD WILL BE NEAR CLIMO
WITH HIGHS IN THE UPPER 80S TO NEAR 90 WITH LOW/MID 70S FOR
OVERNIGHT LOWS.
&&
.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
SHORT TERM /THROUGH 00Z MONDAY/...
AS OF 1250 AM SUN...SHOWERS HAVE MOVED EAST OF THE TAF SITES AND
WITH A LIGHT SW BREEZE AND A 4 TO 6 DEGREE TEMPERATURE/DEWPOINT
SPREAD...NO ISSUES WITH LOW CEILINGS OR VSBYS THUS FAR. THERE
COULD BE SOME MVFR SCU CIGS PRIOR TO 12Z BUT THESE SHOULD BE
SHORT-LIVED. SCT TSTMS DURING THE DAY ALONG AND INLAND OF SEA
BREEZE.
LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 315 AM SUN...SCT THUNDERSHOWERS POSSIBLE EACH DAY FOR THE
TERMINALS WITH MAINLY DRY CONDITIONS AT NIGHT AS PERSISTENT TROUGH
OF LOW PRESSURE REMAINS OVER THE REGION. GENERALLY VFR EXCEPT FOR
TEMPO RESTRICTIONS IN VSBY WITH THE SHOWERS/TSTORMS. 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...ESPECIALLY FOR AREAS THAT
RECEIVE RAINFALL.
&&
.MARINE...
SHORT TERM /TODAY AND TONIGHT/...
AS OF 350 AM SUNDAY...WILL CONTINUE SMALL CRAFT ADVISORY THROUGH 5
AM FOR THE PAMLICO SOUND AND FAR NORTHERN WATERS AND WILL MONITOR
FOR THE NEED TO EXTEND IT INTO MID-MORNING. GUSTY SW WINDS PERSIST
BETWEEN DEEPENING SURFACE TROUGH OVER THE PIEDMONT AND BERMUDA
HIGH PRESSURE TO THE EAST. THESE SW WINDS CONTINUE TO GUST INTO
THE MID 20S...BUT ANY 6 FOOT SEAS ARE ON THE OUTER PERIPHERY OF
THE MARINE ZONES. WINDS AND SEAS SUBSIDE LATER TONIGHT BEFORE
INCREASING AGAIN LATE MONDAY...THUS ANOTHER SCA WILL LIKELY NEED
TO BE ISSUED ONCE CURRENT ADVISORIES EXPIRE.
LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 320 AM SUN...HIGH PRESSURE OFF THE SE COAST WITH A THERMAL
TROUGH INLAND WILL BE THE DOMINANT PATTERN THROUGH MUCH OF THE LONG
TERM. EXPECT A BREAK IN THE GUSTY SW WINDS MON BEFORE REINFORCING
TROUGH/FRONT APPROACH TUES INTO LATE WEEK. MARGINAL SCA CONDITIONS
ARE EXPECTED ONCE AGAIN FROM OREGON INLET SOUTH TUES THROUGH TUES
NIGHT AS THE GRADIENT INCREASES A BIT. NO SIGNIFICANT CHANGES TO
THE MEDIUM AND LONG TERM. WINDS SHOULD BECOME LIGHT LATE IN THE
WEEK AS GRADIENT RELAXES WITH TROUGH AXIS OVER OR JUST EAST OF THE
WATERS.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EDT EARLY THIS MORNING FOR
AMZ135-150.
SMALL CRAFT ADVISORY UNTIL 1 AM EDT MONDAY FOR AMZ152-154-156-
158.
&&
$$
SYNOPSIS...CTC
NEAR TERM...CTC
SHORT TERM...CTC
LONG TERM...DAG
AVIATION...CTC/DAG
MARINE...CTC/DAG
AREA FORECAST DISCUSSION...CORRECTED
NWS BISMARCK ND
1237 AM CDT SUN JUL 21 2013
.UPDATE...
ISSUED AT 1221 AM CDT SUN JUL 21 2013
THE INHERITED FORECAST FOR THE REMAINDER OF TONIGHT IS ON TRACK
AND BLENDED TO THE 05 UTC OBSERVED TRENDS. THE FOCUS IS ON THE
SEVERE THUNDERSTORM THREAT FOR SUNDAY...WHICH NOW INCLUDES A
GREATER PORTION OF THE AREA COMPARED TO THE DAY 2 OUTLOOK FOR
SUNDAY. AREAS EAST OF HIGHWAY 85 HAVE THE GREATEST POTENTIAL FOR
SEVERE CONVECTION SUNDAY AFTERNOON AND EVENING. SEE THE NEW SPC
DAY 1 OUTLOOK FOR DETAILS.
UPDATE ISSUED AT 834 PM CDT SAT JUL 20 2013
LATEST REGIONAL RADAR SHOWS AN AREA OF SEVERE THUNDERSTORMS IN
EASTERN MONTANA MOVING SOUTHEAST WITH TIME. MONITORING FOR ANY
OUTFLOWS...WITH CURRENT MOVEMENT INDICATING THAT THIS AREA COULD
MOVE INTO OUR FAR SOUTHWESTERN COUNTIES OF GOLDEN VALLEY/SLOPE/BOWMAN
IN THE NEXT COUPLE OF HOURS. OTHERWISE EXPECT ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS OVERNIGHT...WITH INCREASING WARM AIR
ADVECTION ASSOCIATED WITH A WARM FRONT OVER EASTERN MONTANA. STILL
SOME ISOLATED CONVECTION IN NORTHWESTERN SOUTH DAKOTA BUT NOTHING
SEVERE AT THIS TIME. MINOR CHANGES FROM PREVIOUS FORECAST.
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 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1221 AM CDT SUN JUL 21 2013
THE MAIN AVIATION HAZARD WITH THE 06 UTC TAF CYCLE WILL BE A
POSSIBLE ROUND OF SEVERE THUNDERSTORMS TO POTENTIALLY IMPACT
KBIS...KMOT AND KJMS POST 21 UTC. OTHERWISE...MVFR STRATUS IS
POSSIBLE ACROSS THE AREA TONIGHT WITH WEAK EASTERLY UPSLOPE FLOW
WITH SOME STATUS ALREADY FORMING ON SATELLITE.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...WAA
LONG TERM...JPM
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1221 AM CDT SUN JUL 21 2013
.UPDATE...
ISSUED AT 1221 AM CDT SUN JUL 21 2013
THE INHERITED FORECAST FOR THE REMAINDER OF TONIGHT IS ON TRACK
AND BLENDED TO THE 05 UTC OBSERVED TRENDS. THE FOCUS IS ON THE
SEVERE THUNDERSTORM THREAT FOR SUNDAY...WHICH NOW INCLUDES A
GREATER PORTION OF THE AREA COMPARED TO THE DAY 2 OUTLOOK FOR
SUNDAY. AREAS EAST OF HIGHWAY 85 HAVE THE GREATEST POTENTIAL FOR
SEVERE CONVECTION SUNDAY AFTERNOON AND EVENING. SEE THE NEW SPC
DAY 1 OUTLOOK FOR DETAILS.
UPDATE ISSUED AT 834 PM CDT SAT JUL 20 2013
LATEST REGIONAL RADAR SHOWS AN AREA OF SEVERE THUNDERSTORMS IN
EASTERN MONTANA MOVING SOUTHEAST WITH TIME. MONITORING FOR ANY
OUTFLOWS...WITH CURRENT MOVEMENT INDICATING THAT THIS AREA COULD
MOVE INTO OUR FAR SOUTHWESTERN COUNTIES OF GOLDEN VALLEY/SLOPE/BOWMAN
IN THE NEXT COUPLE OF HOURS. OTHERWISE EXPECT ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS OVERNIGHT...WITH INCREASING WARM AIR
ADVECTION ASSOCIATED WITH A WARM FRONT OVER EASTERN MONTANA. STILL
SOME ISOLATED CONVECTION IN NORTHWESTERN SOUTH DAKOTA BUT NOTHING
SEVERE AT THIS TIME. MINOR CHANGES FROM PREVIOUS FORECAST.
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 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1221 AM CDT SUN JUL 21 2013
THE MAIN AVIATION HAZARD WITH THE 06 UTC TAF CYCLE WILL BE A
POSSIBLE ROUND OF SEVERE THUNDERSTORMS TO POTENTIALLY IMPACT
KBIS...KMOT AND KJMS POST 21 UTC. OUTSIDE OF THIS THREAT...VFR
CONDITIONS ARE EXPECTED.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...WAA
LONG TERM...JPM
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
156 AM EDT SUN JUL 21 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE SOUTHEAST WILL WEAKEN DURING THE REMAINDER OF
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 TODAY/...
AS OF 200 AM...CONDITIONS REMAIN RATHER CALM ACROSS THE REGION AS
EARLIER CONVECTION HAS CEASED. LOW CLOUDS CONTINUE TO PREVAIL
ACROSS MOST LOCATIONS WITH PATCHY FOG REMAINING LIKELY THROUGH
MORNING. ADJUSTED TEMPERATURES AND DEWPOINTS TO REFLECT LATEST
OBSERVATIONS AND LEFT THE REMAINDER OF FORECAST AS IS.
PREVIOUS DISCUSSION...
1015 PM UPDATE...THUNDERSTORMS PERSIST AT THIS HOUR IN THE VICINITY
OF A REMNANT GUST FRONT EXTENDING ACROSS THE LOWER SC PIEDMONT AND
SOUTH SIDE OF THE CHARLOTTE METRO. LATEST SPC MESOANALYSIS SHOWS
NEARLY 2000 J OF SBCAPE STILL UNINHIBITED JUST SOUTH OF THIS
BOUNDARY...AS WELL AS A THERMAL GRADIENT IN THE SAME AREA THAT IS
LIKELY PROVIDING ENOUGH FORCING TO GET PARCELS GOING. LIGHT SLY FLOW
ON THE S SIDE OF THE BDY WILL CONTINUE TO REINFORCE THE GRADIENT AND
IT MAY TAKE SOME TIME FOR THE REMNANT INSTABILITY TO BE CONSUMED.
LATEST HRRR SUPPORTS THIS CONCEPT AS WELL AS THE SCHC POP WHICH HAS
BEEN MAINTAINED OVERNIGHT FOR MOST OF THE CWFA...AS IT FEATURES A
COUPLE OF ISOLATED CELLS HERE AND THERE...ESPECIALLY NEAR THE BLUE
RIDGE.
ON A FINAL NOTE...PATCHY FOG ALREADY DEVELOPING AT SOME
SITES...PRIMARILY SITES WHICH SAW HEAVY RAIN THIS AFTN. FOLLOWING
THAT THINKING THE MAIN AREA OF CONCERN WOULD BE THE FOOTHILLS AND
UPPER PIEDMONT. AT THIS TIME THE REPORTING SITES ARE TOO SCATTERED
TO NEED A DENSE FOG ADVY...AND NAM SOUNDINGS ARE NOT SUPPORTIVE OF
WIDESPREAD DENSE FOG ANYWAY. HOWEVER...IT BEARS MONITORING AND WILL
INFORM INCOMING SHIFT OF THIS CONCERN.
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 /TONIGHT 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 /06Z SUNDAY THROUGH THURSDAY/...
AT KCLT...CONTINUED WITH MOSTLY PERSISTENCE FORECAST FROM LAST
NIGHT. EXPECTING MVFR FOG CONDITIONS TO DEVELOP IN THE NEXT HOUR OR
SO ACROSS THE NC PIEDMONT WITH CIGS LESS THAT 1K FT.
OTHERWISE...MVFR CONDITIONS WILL PREVAIL THROUGH MID MORNING THEN
FINALLY GIVE WAY TO LOW END VFR CIGS BY AROUND NOON. AT THAT
TIME...INTRODUCED MVFR PROB30 IN THE TAF FOR POSSIBLE AFTERNOON
CONVECTION. EXPECTING AS MUCH...IF NOT MORE COVERAGE ACROSS THE
REGION TODAY AS THE ATMOSPHERE CONTINUES TO MOISTEN. AFTER
SUNSET EXPECTING CIGS TO LIFT ACROSS THE PIEDMONT TO SOLID VFR
LEVELS AND REMAIN THAT WAY THROUGH THE REMAINDER OF THE TAF CYCLE.
EXPECTING WINDS DURING THE PERIOD TO REMAIN LIGHT AND
SOUTHWESTERLY.
ELSEWHERE...RESTRICTIONS WILL CONTINUE...IF NOT WORSEN ACROSS
THE REGION IN THE NEXT FEW HOURS AS VERY MOIST BOUNDARY LAYER
SETTLES. LIKELY A REPEAT OF LAST NIGHT WITH REGARDS TO MVFR/IFR
CIGS AT MOST SITES. IN ADDITION...ADDED TEMPO GROUPS FOR VISB
RESTRICTIVE FOG AT ALL SITES WITH KAVL DROPPING DOWN TO AN IFR
VISB. OTHERWISE...MUCH OF THE SAME AS KCLT ABOVE AS FAR AS MID
MORNING LOW END VFR CIGS OVERSPREADING MOST OF THE AREA. BEYOND
THAT...ADDED PROB30 GROUPS AT ALL SITES FOR MVFR TSRA RESTRICTIONS
DURING THE LATE MORNING/AFTERNOON HOURS. EXPECTING CONVECTION TO
INITIATE ACROSS THE HIGH TERRAIN FIRST...THEN SPREAD EASTWARD
THROUGH THE PIEDMONT. CONDITIONS WILL IMPROVE THIS EVENING AS
DAYTIME HEATING IS LOST AFTER SUNSET...WHERE SOLID VFR CIGS WILL
RETURN. WINDS THROUGH THE PERIOD WILL BE LIGHT AND SOUTHWESTERLY.
OUTLOOK...MOIST SOUTHWESTERLY FLOW CONTINUES INTO THE EARLY WEEK.
THIS WILL HELP DRIVE SHOWERS AND THUNDERSTORMS...MAINLY IN THE
AFTERNOON AND EVENING...AND LIKELY CAUSE RESTRICTIVE CIGS/VSBYS
EARLY EACH MORNING.
CONFIDENCE TABLE...
06-12Z 12-18Z 18-24Z 00-06Z
KCLT LOW 57% MED 79% HIGH 100% HIGH 100%
KGSP MED 69% MED 77% HIGH 100% HIGH 100%
KAVL MED 64% LOW 58% LOW 58% HIGH 100%
KHKY MED 67% LOW 51% HIGH 85% MED 75%
KGMU MED 71% LOW 59% HIGH 86% HIGH 100%
KAND LOW 56% MED 77% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...PAT
NEAR TERM...CDG/JAT/WIMBERLEY
SHORT TERM...LGL
LONG TERM...LGL
AVIATION...CDG
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1227 AM CDT SUN JUL 21 2013
.UPDATE...
SEE UPDATED AVIATION DISCUSSION BELOW.
&&
.PREVIOUS DISCUSSION...
.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...
06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
VFR CONDITIONS ARE EXPECTED AT ALL TAF LOCATIONS THROUGH TONIGHT
AND SUNDAY. A FEW SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS
THE REGION TONIGHT AND SUNDAY AND MAY AFFECT THE TERMINALS AT OR
IN THE VICINITY. WILL WATCH FOR POSSIBLE AMENDMENTS.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
SHORT TERM...SD
LONG TERM...WISE
AVIATION...PARKIN
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1147 PM CDT SAT JUL 20 2013
.DISCUSSION...
SEE AVIATION DISCUSSION BELOW/
&&
.AVIATION...
MOSTLY VFR CONDITIONS ARE EXPECTED ACROSS THE FORECAST AREA THE
NEXT 24 HOURS.
SHOWERS EARLIER THIS EVENING HAVE DISSIPATED AS NIGHTTIME LAND
SURFACE COOLING HAS STABILIZED THE AIR MASS AND IS HELPING PREVENT
SHOWERS FROM DEVELOPING.
A MODEST SURGE OF SOUTH AND SOUTHEAST WINDS FROM THE GULF OF
MEXICO WILL ADVANCE INTO THE AREA LATE SUNDAY. SOUTH AND SOUTHEAST
WINDS ARE EXPECTED TO INCREASE TO 10 TO 15 MPH WITH A FEW HIGHER
GUSTS BY LATE AFTERNOON SUNDAY. THIS WIND AND MOISTURE SURGE MAY
INITIATE ISOLATED TO POSSIBLY SCATTERED SHOWERS...SPECIALLY
ACROSS AREAS SOUTH OF SAN ANGELO...INCLUDING CROCKETT...SUTTON...
KIMBLE...MASON...MENARD AND SCHLEICHER COUNTIES. THE PRIMARY
AVIATION HAZARD WILL BE THE POSSIBILITY OF LIGHTNING.
&&
.PREV DISCUSSION... /ISSUED 953 PM CDT SAT JUL 20 2013/
UPDATE...
DIURNALLY DRIVEN SHOWERS HAVE DISSIPATED ACROSS WEST CENTRAL TX
BUT WE CONTINUE TO SEE ECHOES ROTATING TO THE NORTHWEST AROUND
THE MID/UPPER LEVEL CYCLONE NEAR THE BIG BEND. POPS WERE REMOVED
ACROSS MOST OF THE FORECAST AREA THROUGH THE REMAINDER OF THE
OVERNIGHT PERIOD BUT I DID RETAIN A SLIGHT CHANCE OF SHOWERS IN
THE SOUTH...MAINLY CROCKETT AND SUTTON COUNTIES DUE TO THE
PROXIMITY OF THIS UPPER LOW. BOTH THE 3K TTU WRF AND HRRR DEPICT
WEAK CONVECTION MOVING INTO THIS AREA AFTER MIDNIGHT.
OTHERWISE...ONLY MINOR MODIFICATIONS WERE MADE TO THE INHERITED
FORECAST.
JOHNSON
PREV DISCUSSION... /ISSUED 633 PM CDT SAT JUL 20 2013/
DISCUSSION...
SEE AVIATION DISCUSSION BELOW/
AVIATION...
CURRENTLY ISOLATED SHOWERS HAVE DEVELOPED ACROSS
MASON...MCCULLOUGH...MENARD...COLEMAN...SHACKELFORD AND SUTTON
COUNTIES. AN ISOLATED SHOWER WAS NOTED JUST NORTH OF SAN ANGELO.
MOST OF THESE SHOWERS ARE EXPECTED TO DISSIPATE AFTER SUNSET.
ON SUNDAY THERE IS POTENTIAL FOR ISOLATED SHOWERS TO REDEVELOP...
CAUSED BY AFTERNOON HEATING THAT WILL CAUSE WARM AIR TO RISE
THROUGH A WEAKLY CAPPED ATMOSPHERE THAT HAS MOIST AIR IN THE
LOWEST 5K FEET. THE MOST LIKELY SHOWER AREAS WILL BE ACROSS
MASON...KIMBLE... SUTTON...MENARD AND SAN SABA COUNTIES.
HOWEVER...MOSTLY VFR CONDITIONS WILL PREVAIL THE NEXT 24 HOURS
ACROSS THE FORECAST AREA.
PREV DISCUSSION... /ISSUED 349 PM CDT SAT JUL 20 2013/
SHORT TERM...
/TONIGHT AND SUNDAY/
ISOLATED BRIEF SHOWERS AND THUNDERSTORMS INTO SUNDAY...
MOIST LOW LEVEL MOISTURE WILL CONTINUE WITH A WEAKLY OR UNCAPPED
ATMOSPHERE INTO SUNDAY. MOST STORMS EXPECTED TO DEVELOP MID AND
LATE AFTERNOON UNDER MAXIMUM HEATING...THEN DISSIPATE AFTER SUNSET.
HOWEVER...A FEW STORMS MAY LAST LONGER OVER SOUTHERN SECTIONS ALONG
THE I-10 CORRIDOR AT NIGHT WHERE THE THE UPPER RIDGE IS WEAKEST.
BRIEF HEAVY RAIN IS POSSIBLE IN SLOW MOVING STORMS.
LONG TERM...
THERE IS A SLIGHT CHANCE FOR SHOWERS AND THUNDERSTORMS ACROSS
SOUTHERN SECTIONS ON MONDAY WITH DRY AND WARMER WEATHER FOR THE
REMAINDER OF NEXT WEEK.
A WEAK UPPER LEVEL LOW WILL BE SITUATED NEAR THE BIG BEND SUNDAY
EVENING AND WILL DRIFT SOUTHWEST INTO NORTHERN MEXICO BY TUESDAY
AFTERNOON. WE WILL STILL SEE A DECENT AMOUNT OF LOW AND MID LEVEL
MOISTURE AROUND...ESPECIALLY ACROSS SOUTHERN SECTIONS ON MONDAY.
KEPT INHERITED LOW POPS INTACT MAINLY OVER THE NORTHWEST HILL
COUNTRY AND NORTHERN EDWARDS PLATEAU MONDAY AND MONDAY EVENING
WHERE WIDELY SCATTERED SHOWERS AND FEW THUNDERSTORMS WILL BE
POSSIBLE. HIGHS ON MONDAY WILL BE MAINLY IN THE LOW TO MID 90S
WITH A FEW READINGS IN THE UPPER 90S ACROSS THE NORTHERN BIG
COUNTRY.
AN UPPER LEVEL RIDGE WILL BUILD SOUTHEAST ACROSS THE SOUTHERN
ROCKIES AND INTO CENTRAL TEXAS TUESDAY THROUGH THE END OF THE
WEEK. THE ECMWF DOES SHUNT THE RIDGE BACK TO THE WEST FRIDAY
INTO SATURDAY AS A SHORT WAVE DROPS SOUTHEAST FROM THE NORTHERN
ROCKIES...WITH AN ASSOCIATED WEAK COLD FRONT ENTERING THE AREA.
THE GFS MAINTAINS A STRONGER RIDGE WITH THE FRONT REMAINING NORTH
OF THE AREA. KEPT A DRY FORECAST GOING FOR NOW GIVEN THESE MODEL
DISCREPANCIES. HIGH TEMPERATURES WILL WARM FROM THE LOW TO MID 90S
ON TUESDAY...TO THE MID AND UPPER 90S WEDNESDAY THROUGH SATURDAY.
OVERNIGHT LOWS WILL MAINLY BE IN THE LOWER 70S THROUGH THE PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 71 93 72 94 74 / 5 10 10 10 10
SAN ANGELO 70 93 72 94 74 / 10 20 10 20 10
JUNCTION 70 92 72 93 73 / 10 30 20 20 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
99/99/99
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
300 AM CDT SUN JUL 21 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 300 AM CDT SUN JUL 21 2013
CURRENTLY AS OF 08Z...
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS LOOKED VERY SIMILAR
TO THIS TIME YESTERDAY...CONSISTING OF NORTHWEST FLOW FROM BRITISH
COLUMBIA INTO THE GREAT LAKES REGION...NUMEROUS SHORTWAVES RIDING
THROUGH THE FLOW...AND TROUGHING OVER SOUTHEAST CANADA. MOST OF THE
SHORTWAVES ARE WEAK EXCEPT FOR A MORE IMPRESSIVE ONE OVER CENTRAL
ALBERTA. THE MAIN SHORTWAVE OF INTEREST IN THE SHORT TERM IS
ORIGINATING OUT OF CONVECTION OVER SOUTHEAST SD AND EASTERN
NEBRASKA. AIRMASS OVER THE FORECAST AREA VARIES GREATLY FROM SOUTH
TO NORTH WITH I-94 BEING A GREAT DIVIDING LINE. TO THE NORTH...DRIER
AIR CHARACTERIZED BY SURFACE DEWPOINTS IN THE 40S AND LOW 50S WAS
PRESENT. FARTHER UP TO THE NORTH...THE 00Z INL SOUNDING REPORTED A
PRECIPITABLE WATER VALUE OF 0.49 INCHES. NOW...SOUTH AND WEST OF
I-94...DEWPOINTS ARE IN THE 60S. THE 00Z SOUNDINGS FROM MPX AND DVN
HAD PRECIPITABLE WATER VALUES AROUND 1.15 INCHES. SEPARATING THESE
TWO AIRMASSES IS A STATIONARY FRONTAL BOUNDARY. ISOLATED
SHOWERS/STORMS HAVE BEEN POPPING UP ALONG/NORTH OF THE BOUNDARY ALL
NIGHT.
SYNOPTIC OVERVIEW...
NORTHWEST FLOW CONTINUES THROUGH THE SHORT TERM PERIOD. THE
CONVECTIVELY INDUCED SHORTWAVE TROUGH APPROACHING SIOUX CITY IA AT
08Z MODELS ARE STRUGGLING WITH GREATLY. MOST MODELS...INCLUDING HI
RESOLUTION RUNS SUCH AS THE HRRR AND HIRES-ARW ARE TOO SLOW.
EXTRAPOLATION HAS THE MCV CROSSING MUCH OF IOWA THIS MORNING.
POTENTIAL THEN EXISTS FOR SOME VERY WEAK RIDGING IN ITS WAKE FOR
THIS AFTERNOON AND TONIGHT...AHEAD OF THE CURRENT ALBERTA SHORTWAVE
WHICH DIGS INTO NORTHERN MN AND WESTERN ONTARIO BY 12Z MONDAY.
TODAY...
DESPITE THIS PERIOD BEING THE BEGINNING OF THE FORECAST...THE
UNCERTAINTY IS QUITE HIGH. MUCH OF THIS UNCERTAINTY STEMS FROM THE
TOO SLOW HANDLING FROM ALL MODELS REGARDING THE MCV APPROACHING
SIOUX CITY IA AS OF 08Z. GENERALLY FOLLOWED AN EXTRAPOLATION
APPROACH COMBINED WITH A SOMEWHAT SPED UP 21.05Z HRRR FORECAST TO
COME UP WITH THE FORECAST TODAY. THE PLAN IS THAT THE MCV SHOULD
TRACK ACROSS DES MOINES AND DAVENPORT THIS MORNING...WITH THE
FORECAST AREA ON THE NORTH SIDE. SHOWERS AND A FEW EMBEDDED
THUNDERSTORMS APPEAR LIKELY...PRIMARILY WEST OF THE MISSISSIPPI
RIVER DURING THE MORNING HOURS. CONCERNED THAT THE DIURNAL EFFECTS
ON LOW LEVEL MOISTURE TRANSPORT MAY CAUSE THE SHOWERS TO WEAKEN SOME
AS WE APPROACH MID-DAY...THUS THE HIGHER CHANCES TO THE WEST. DURING
THE AFTERNOON...IT IS HARD TO SAY WHATS GOING TO OCCUR. WE COULD
EASILY BE IN SUBSIDENCE IN THE WAKE OF THE MCV...PREVENTING MUCH IN
THE WAY OF ADDITIONAL PRECIPITATION. ON THE OTHER HAND...THE
AFTERNOON IS PEAK HEATING AND WITH HIGHER DEWPOINTS TODAY...WE
SHOULD BE ABLE TO BUILD 500-1500 J/KG OF CAPE AS SUGGESTED BY THE
RAP. ANY SHORTWAVE COMING THROUGH THE NORTHWEST FLOW THATS HARD TO
DISCERN AT THIS TIME COULD KICK OFF SHOWERS AND STORMS. ADDITIONALLY
WE SHOULD STILL HAVE THAT STATIONARY FRONTAL BOUNDARY IN THE
FORECAST AREA TO PROVIDE WEAK LOW LEVEL CONVERGENCE. THEREFORE...
HAVE MAINTAINED AT LEAST 40-50 PERCENT CHANCES FOR THE AFTERNOON.
REGARDING TEMPERATURES...ASSUMING SOME SUN TODAY WHICH SHOULD
OCCUR...925MB TEMPS IN THE 18-20C RANGE SUPPORTS HIGHS IN THE 70S TO
NEAR 80.
TONIGHT...
ANY CONVECTION THAT OCCURS THIS AFTERNOON WILL LIKELY HAVE A STRONG
DIURNAL COMPONENT TO IT. THEREFORE...HAVE PRECIPITATION CHANCES
DIMINISHING THROUGH THE EVENING HOURS. HOWEVER...850MB MOISTURE
TRANSPORT DOES INCREASE THROUGH THE NIGHT AHEAD OF THE STRONGER
SHORTWAVE DROPPING INTO NORTHERN MN. CONVECTION WILL LIKELY FORM ON
THE NOSE OF THIS MOISTURE TRANSPORT...WHICH IS FORECAST FROM
NORTHERN MN INTO NORTHERN WI. KEPT SOME 20 PERCENT CHANCES OVERNIGHT
BOTH OVER TAYLOR/CLARK COUNTIES FOR THE NOSE OF THIS MOISTURE
TRANSPORT. ALSO KEPT THE 20 PERCENT CHANCES OVERNIGHT FOR THE
EASTERN HALF OF THE FORECAST AREA...IN THE EVENT ANY DIURNAL
CONVECTION CAN SURVIVE...THOUGH AS THE CHANCE STATES THE CONFIDENCE
IS LOW.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 300 AM CDT SUN JUL 21 2013
SYNOPTIC OVERVIEW...
20.00Z ECMWF/GFS/CANADIAN ALL CONTINUE THE NORTHWEST FLOW PATTERN
THROUGH THE ENTIRE LONG TERM PERIOD. WHAT LOOKED TO BE A POSSIBILITY
OF RIDGING BUILDING TOWARDS THE AREA BRIEFLY THURSDAY INTO FRIDAY IS
NOW COMPLETELY GONE. PART OF THE REASON WE STAY IN NORTHWEST FLOW IS
THE DEVELOPMENT OF AN OMEGA BLOCK OVER WESTERN CANADA BETWEEN
TUESDAY AND WEDNESDAY...WHICH DOES NOT SHOW ANY SIGNS OF BREAKING
DOWN FOR AWHILE. ADDITIONALLY...THERE APPEARS TO BE SOME MODEL
STRUGGLES HANDLING SHORTWAVE TROUGHING COMING DOWN THE EAST SIDE OF
THE OMEGA BLOCK...WHICH PUTS MORE UNCERTAINTY FOR THE FORECAST
THURSDAY AND BEYOND. ONE THING THAT IS STARTING TO BECOME A LITTLE
MORE EVIDENT IS FOR DEEPER TROUGHING OVER THE GREAT LAKES REGION AT
THE END OF NEXT WEEKEND. 500MB STANDARDIZED ANOMALIES FOR 12Z SUNDAY
FROM THE ECMWF/GFS ARE 1.5-2 BELOW NORMAL.
HAZARDS...
THERE COULD BE SOME ISOLATED SEVERE WEATHER LATE MONDAY AFTERNOON
INTO THE EVENING HOURS...ASSOCIATED WITH A COLD FRONT COMING
THROUGH...BUT CONFIDENCE IS LOW AS DESCRIBED BELOW.
MONDAY THROUGH TUESDAY NIGHT...
MUCH OF THE FOCUS HERE IS ON THE MONDAY/MONDAY NIGHT PERIOD.
SHORTWAVE TROUGH OVER NORTHERN MN AND WESTERN ONTARIO AT 12Z MONDAY
MODELS ALL AGREE ON SLIDING IT ACROSS NORTHERN ONTARIO. AS THIS
OCCURS...A COLD FRONT ASSOCIATED WITH IT APPROACHES THE FORECAST
AREA. TIMING ON THIS FRONT VARIES GREATLY. AT 00Z TUESDAY...TIMING
VARIES FROM THE 21.00Z HIRES-ARW HAVING IT WEST OF MINNEAPOLIS TO
THE 21.00Z ECMWF/GFS OVER MINNEAPOLIS AND THE 21.00Z
CANADIAN/NAM/UKMET WHICH ARE OVER LA CROSSE. TRENDS AT LEAST FROM
THE ECMWF/GFS SUGGEST A SLOWER APPROACH MAY BE THE WAY TO GO. THERE
STILL REMAINS UNCERTAINTY ON CONVECTIVE CHANCES WITH THIS
FRONT...
1. A WARM SURGE OF AIR AT 800MB IS STILL INDICATED TO COME OVER THE
FRONT TO PROVIDING POTENTIAL CAPPING
2. THE SHORTWAVE TROUGH SLIDING ACROSS NORTHERN ONTARIO COULD END UP
PUTTING RIDGING OVER THE FRONT FOR THE AFTERNOON AS SUGGESTED BY THE
21.00Z HIRES-ARW.
3. LOW LEVEL CONVERGENCE ON THE FRONT REMAINS IN QUESTION.
4. NOW THE FRONT BEING SLOWER...NOT COMING ACROSS THE FORECAST AREA
AT PEAK HEATING...COULD BE A NEGATIVE FOR PRECIP.
TO ACCOUNT FOR THE SLOWER TREND HAVE LOWERED PRECIPITATION CHANCES
SOME MONDAY AFTERNOON. LEFT THE 40-60 PERCENT CHANCES FOR MONDAY
EVENING AS THAT IS STILL FAIRLY WELL AGREED UPON BY GUIDANCE...THEN
CHANCES DIMINISHING AFTER MIDNIGHT WITH LOSS OF HEATING AND THE
FRONT PROGRESSING THROUGH THE AREA. DRY WEATHER FOLLOWS IN THE WAKE
OF THE FRONT FOR TUESDAY AND TUESDAY NIGHT WHILE HIGH PRESSURE
BUILDS IN AT THE SURFACE. 925MB TEMPS CLIMBING TO 21-24C AHEAD OF
THE FRONT ON MONDAY PLUS SUNSHINE WILL ALLOW HIGHS TO CLIMB INTO THE
80S. MAY EVEN SEE 90 IN A FEW SPOTS IF MORE SUN OCCURS. MONDAY LOOKS
HUMID AS WELL AS NEAR 70 DEGREE DEWPOINTS ADVECT IN AT THE SURFACE.
COOLER HIGHS ON THE WAY FOR TUESDAY AS 925MB TEMPS TUMBLE TO 17-20C.
TUESDAY NIGHT LOWS HAVE POTENTIAL TO GET INTO THE 40S AT THE TYPICAL
COLDER SPOTS...DUE TO LIGHT WINDS AND PRECIPITABLE WATER VALUES
FALLING TO 0.5-0.75 INCHES.
WEDNESDAY THROUGH SATURDAY NIGHT...
20.00Z ECMWF/GFS/CANADIAN ARE SUGGESTING NUMEROUS WEAK SHORTWAVES
DROP SOUTHEAST ACROSS THE FORECAST AREA WEDNESDAY THROUGH THURSDAY
IN THE NORTHWEST FLOW ALOFT. HARD TO SAY IF ANY OF THESE ARE GOING
TO DO ANYTHING PRECIP WISE. 20.00Z CANADIAN AND 19.12Z ECMWF WANT TO
BRING SOME SHOWERS ACROSS WEDNESDAY NIGHT AND THURSDAY...THOUGH THE
20.00Z ECMWF BACKED OFF. WOULD THINK A DRIER SCENARIO IS MORE LIKELY
GIVEN THE DRY AIRMASS COMING IN TUESDAY NIGHT/WEDNESDAY WITH
CANADIAN HIGH PRESSURE IN PLACE. NEVERTHELESS...DID HONOR A 20
PERCENT CHANCE MAINLY ON THURSDAY JUST IN CASE. CHANCES INCREASE A
LITTLE FOR THURSDAY NIGHT AND FRIDAY WHERE IT APPEARS A COLD FRONT
WILL CROSS THE AREA...ASSOCIATED WITH A POTENT UPPER TROUGH DROPPING
OVER MANITOBA AND NORTHERN ONTARIO. SOME OF THIS UPPER TROUGH LOOKS
TO SWING ACROSS THE FORECAST AREA FRIDAY NIGHT AND SATURDAY...THUS
STILL NEED TO CONTINUE AT LEAST 20 PERCENT CHANCES. BEING IN THIS
NORTHWEST FLOW PATTERN COMBINED WITH EVEN DEEPER TROUGHING FORMING
OVER THE WEEKEND SUGGESTS BELOW NORMAL TEMPERATURES. BY 12Z
SUNDAY...BOTH THE 20.00Z ECMWF AND GFS DEPICT 850MB TEMPS FALLING TO
6-9C...CHILLY RELATIVELY SPEAKING FOR THE END OF JULY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1030 PM CDT SAT JUL 20 2013
MUDDLED WEATHER PICTURE WITH AN UNSTABLE AIRMASS INTERACTING WITH
VARIOUS MESOSCALE SFC BOUNDARIES AND A FEW PERTURBATIONS IN THE
UPPER LEVEL FLOW. THERE WILL BE PERIODS OF SHRA/TS ACROSS THE REGION
THROUGH SUNDAY NIGHT...BUT TRYING TO HIGHLIGHT WHEN THE TAF SITES
WOULD BE IMPACTED IS PROBLEMATIC AT BEST. CONFIDENCE IS LOW IN
REFINING THE PCPN FORECAST AND MIGHT HAVE TO WAIT UNTIL PCPN IS
ACTUALLY DEVELOPING TO FINE TUNE THE TAFS. THE MOST WIDESPREAD PCPN
SHOULD BE TIED WITH THE UPPER LEVEL SHORTWAVES. WILL CONTINUE TO
PAINT WITH A BROAD BRUSH AS A RESULT. OVERALL...EXPECT VFR
CONDITIONS TO DOMINATE...ALTHOUGH A BRIEF PERIOD OF MVFR COULD
ARISE WITH ANY THUNDERSTORM.
FOR MONDAY...A SFC FRONT IS EXPECTED TO DROP SOUTHWARD INTO THE
AREA. WITH UNSTABLE AIR TO WORK WITH...BELIEVE A LINE OF CONVECTION
WILL DEVELOP IN RESPONSE...AND THERE COULD BE SOME STRONGER STORMS
IN THE AFTERNOON/EARLY EVENING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
540 AM MST SUN JUL 21 2013
.UPDATE...UPDATED AVIATION DISCUSSION.
&&
.SYNOPSIS...
A LOW PRESSURE SYSTEM IN MEXICO WILL CONTINUE TO SUPPLY MOISTURE TO
THE DESERT SOUTHWEST TODAY. HUMID CONDITIONS WILL RESULT IN
WELL-ABOVE NORMAL RAIN CHANCES AND WELL-BELOW NORMAL TEMPERATURES. A
DRYING TREND WILL BEGIN MONDAY...CONTINUING INTO WEDNESDAY AS
HIGH PRESSURE BUILDS BACK OVER THE REGION. MONSOON MOISTURE MOVING
BACK NORTHWARD INTO THE REGION IS LIKELY TO ONCE AGAIN INCREASE RAIN
CHANCES FOR THE END OF THE WEEK AND INTO THE WEEKEND.
&&
.DISCUSSION...
UPPER LOW CONTINUES TO SPIN WESTWARD INTO THE PACIFIC OCEAN JUST OFF
THE BAJA PENINSULA. FURTHER NORTH...THE MID-TROPOSPHERIC ANTICYCLONE
REMAINS POSITIONED ACROSS CA/NV. RESULTING MID-LEVEL EASTERLY FLOW
IS STRONGER THAN NORMAL (STANDARDIZED ANOMALY NEAR 1.0) AND
CONTINUES TO ADVECT DEEP SUB-TROPICAL MOISTURE INTO THE FORECAST
AREA. SURFACE DEWPOINTS ARE CURRENTLY IN THE LOWER 70S ACROSS THE
PHOENIX METRO AREA WHILE THE GPS-IPW REGISTERED AROUND 1.75
INCHES...WELL ABOVE NORMAL. LATEST RAP INDICATES THAT PWATS MAY BE
AS HIGH AS 2.0 TO 2.4 INCHES ACROSS THE SOUTHWEST DESERTS AND
TOWARDS PUERTO PENASCO.
LATEST WV IMAGERY SHOWS TWO MCS...ONE ACROSS THE MOJAVE DESERT AND
THE OTHER ACROSS SOUTHERN AZ...BEARING DOWN ON SW AZ AND SE CA.
STRONG LOW-LEVEL CONVERGENCE IS EXPECTED EARLY THIS MORNING AND POPS
WERE INCREASED IN THESE AREAS. ACROSS SOUTH-CENTRAL AZ...NMM AND
WRF-BASED GUIDANCE CONTINUES TO SUGGEST THAT SHOWERS WILL REDEVELOP
AS EARLY AS THIS MORNING. THIS SEEMS REASONABLE GIVEN THE AMPLE
MOISTURE AND IT WILL ONLY TAKE A MINIMAL AMOUNT OF HEATING FOR
CONVECTION TO INITIATE. MODELS ALSO SUGGEST THAT VORTICITY-FORCED
ASCENT WILL AID IN THE DEVELOPMENT OF STORMS THIS AFTERNOON ACROSS
SE CA. ANY STORMS THAT DEVELOP WILL HAVE THE POTENTIAL TO PRODUCE
HEAVY RAIN AND LOCALIZED FLOODING. THE COPIOUS AMOUNT OF MOISTURE
WILL ALSO RESULT IN CONSIDERABLE CLOUDINESS ACROSS MUCH OF THE
AREA...WHICH WILL KEEP TEMPERATURES WELL BELOW NORMAL. FORECAST HIGH
FOR PHOENIX IS 95 DEGREES. A MAX TEMP THIS LOW HAS NOT OCCURRED
SINCE MAY 27.
A SIGNIFICANT DRYING TREND WILL TAKE PLACE MONDAY AS THE UPPER LOW
LIFTS STEADILY NORTHWARD. SHOWERS AND THUNDERSTORMS ARE STILL
ANTICIPATED...THOUGH COVERAGE WILL BE NOTICEABLY LESS THAN WHAT HAS
OCCURRED THE PAST FEW DAYS. THE UPPER LOW WILL BE PICKED UP BY THE
WESTERLIES TUESDAY AS THE MONSOON HIGH BECOMES REPOSITIONED ACROSS
THE ROCKIES. GFS/ECMWF DIFFER ON THE AMOUNT OF MOISTURE LEFT OVER
ACROSS THE DESERT SOUTHWEST THOUGH THE CONSENSUS IS THAT IT SHOULD
BE SUFFICIENT FOR ISOLATED THUNDERSTORMS THROUGH THE WEEK. FLOW WILL
BE WEAK AS AN ANTICYCLONE BUILDS BACK ACROSS AZ AND CONVECTION WILL
MAINLY BE RELEGATED TO THE HIGHER TERRAIN. A WARMING TREND IS ALSO
EXPECTED WITH A RETURN TO ABOVE NORMAL TEMPERATURES BY THURSDAY.
MODELS ARE IN GENERALLY GOOD AGREEMENT THAT ANOTHER PVD WILL SLIDE
WESTWARD THROUGH SONORA LATE IN THE WEEK...RESULTING IN AN INFLUX OF
MOISTURE. FORECAST IS FOR BELOW CLIMO POPS THROUGH
MIDWEEK...FOLLOWED BY NEAR CLIMO POPS THURSDAY THROUGH SUNDAY.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL...
NEW STORMS WILL CONTINUE TO DEVELOP TO THE SOUTH AND WEST OF THE
PHOENIX AREA...WITH ACTIVITY SLOWLY BUILDING AROUND AND ENCROACHING
ON THE TERMINALS LATER THIS MORNING AFTER 15Z...PERSISTING INTO THE
AFTERNOON/EARLY EVENING. GENERALLY LIGHT WINDS AND SCT-BKN CLOUD
DECKS AOA 6-8KFT ARE EXPECTED WITH PERIODS OF CIGS LOWERING TO
3-4KFT/VISIBILITIES REDUCED DOWN TO 4SM IN HEAVIER SHOWERS AND
THUNDERSTORMS. STORMS DIMINISH AND SKIES EXPECTED TO IMPROVE AFTER
02Z MONDAY WITH SCT-BKN CLOUD DECKS SETTLING IN AOA 10KFT.
SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH...
ISOLATED SHOWER/THUNDERSTORM ACTIVITY WILL CONTINUE TO FILL IN OVER
SOUTHEAST CALIFORNIA THIS MORNING THROUGH AT LEAST 17Z...WITH GUSTY
OUTFLOWS TO 30KT POSSIBLE AT TIMES...ESPECIALLY NEAR KNYL. SCT-BKN
CLOUD DECKS WITH CIGS DOWN TO AROUND 6-8KFT IN HEAVIER SHOWERS AND
THUNDERSTORMS WITH SKIES/CIGS IMPROVING LATER THIS AFTERNOON. WINDS
S-SELY AROUND 10-15KT THROUGH MUCH OF THE TAF PERIOD ACROSS THE
LOWER COLORADO RIVER VALLEY/KBLH WITH LIGHTER SELY WINDS AT KIPL.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
A SWITCH TO A SOUTHERLY FLOW ALOFT WILL BRING DRYING CONDITIONS AND
ENDING PRECIPITATION CHANCES ACROSS SOUTHEAST CALIFORNIA AND
SOUTHWEST ARIZONA. SLIGHT CHANCES FOR STORMS WILL CONTINUE ACROSS
SOUTH-CENTRAL ARIZONA WITH BETTER CHANCES ACROSS HIGHER TERRAIN
LOCATIONS NORTH AND EAST OF PHOENIX. HUMIDITIES WILL REMAIN ELEVATED
THROUGH THE ENTIRE PERIOD WITH AFTERNOON HUMIDITIES ONLY DROPPING
INTO THE 20-30 PERCENT RANGE WITH GOOD OVERNIGHT RECOVERY.
$$
&&
.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 MIAMI FL
956 AM EDT SUN JUL 21 2013
.UPDATE...
LATEST ANALYSIS SHOWS A LARGE DEEP LAYER RIDGE CENTERED ACROSS
SOUTH CENTRAL FLORIDA NEAR LAKE OKEECHOBEE. WITHIN THIS BOUNDARY,
A WEAKNESS EXISTS AS A WEAK MID LEVEL TROUGH IS LOCATED JUST EAST
OF THE MELBOURNE COAST. STREAMLINE ANALYSIS INDICATES STRONG UPPER
LEVEL DIFFLUENCE IS OCCURRING WHICH IS THE REAL CULPRIT IN
GENERATING STRONG CONVECTION ALONG THIS BOUNDARY. ORIGINAL
THINKING WAS THAT MOST AFTERNOON DEVELOPMENT WOULD BE OVER THE
INTERIOR PORTIONS OF SOUTH FLORIDA BENEATH THE RIDGE AND VERY
LITTLE STORM MOTION. THE TRICKY PART OF THE FORECAST FOR THIS
AFTERNOON IS GOING TO BE WHAT INFLUENCE THE TROUGH AND DIFFLUENCE
MIGHT HAVE ON THE CONVECTION. THERE IS ALSO ABUNDANT CLOUD COVER THAT
COULD LIMIT THE AMOUNT OF DIURNAL HEATING THAT TAKES PLACE.
EARLIER RUNS OF THE HRRR HAD SHOWN VERY LITTLE DEVELOPMENT THIS
AFTERNOON BUT THE 10Z AND 11Z RUNS HAVE TAKEN A BIT OF A DIFFERENT
TURN AND SHOW WIDESPREAD DEVELOPMENT WITH A SLOW DRIFT TOWARDS THE
EAST COAST BY LATE AFTERNOON BUT THEN THE 12Z RUN IS SHOWING
MAINLY SEA BREEZE DEVELOPMENT. SO LATER UPDATES WILL BASICALLY
TAKE ON THE PATTERN OF SUBTLE CHANGES THAT MAY CHANGE THE LOCATION
AND MOVEMENT OF ANY CONVECTIVE DEVELOPMENT THAT MAY TAKE PLACE.
KOB
&&
.PREV DISCUSSION... /ISSUED 708 AM EDT SUN JUL 21 2013/
AVIATION...
VFR CONDITIONS WILL PREVAIL. HIGH PRESSURE WILL CONTINUE TO BUILD
INTO SOUTH FLORIDA THROUGH THE END OF THE TAF PERIOD...BRINGING IN
DRIER LOW/MID LEVEL AIR TO THE REGION. LIGHT WINDS THIS MORNING WILL
BECOME SOUTHEAST AROUND 10 KNOTS FOR THE EAST COAST TAF SITES BY THE
AFTERNOON AS THE SEA BREEZE PUSHES INLAND. FOR KAPF...WINDS WILL
SHIFT TO THE SOUTHWEST AROUND 8-10 KNOTS AS THE SEA BREEZE PUSHES
INLAND. WITH THE DRIER AIR...EXPECT SHOWER AND THUNDERSTORM ACTIVITY
TO BE LIMITED AND REMAIN ACROSS THE INTERIOR. LIGHT WINDS ARE
EXPECTED AGAIN OVERNIGHT.
PREV DISCUSSION... /ISSUED 337 AM EDT SUN JUL 21 2013/
DISCUSSION...
THE WEAK TROPICAL WAVE THAT AFFECTED THE WEATHER ON SATURDAY WILL
CONTINUE TO PUSH WESTWARD ACROSS SOUTH FLORIDA THIS MORNING AND MOVE
INTO THE WESTERN GULF ON SUNDAY AFTERNOON. FOR SUNDAY...DRIER AIR
WILL BEGIN TO SPREAD NORTH INTO THE AREA AS THE RIDGE BEGINS TO
BUILD OVER FLORIDA AND THE WEAK TROUGH LIFTS AWAY FROM THE AREA.
HOWEVER...LINGERING MOISTURE OVER THE NORTHERN HALF OF THE CWA...OR
AROUND THE LAKE REGION...WITH PWAT VALUES AROUND 2" COMBINED WITH SW
LOW-LEVEL FLOW WILL BE ENOUGH TO THE KEEP THE AFTERNOON/EVENING
SHOWERS/TSTMS IN THE FORECAST. BETWEEN NOW AND SUNRISE SHOWERS AND
THUNDERSTORMS ARE FORECAST FOR PORTIONS OF THE ATLANTIC AND GULF
WATERS.
THE LARGE SCALE WEATHER PATTERN INDICATES THAT AN AREA OF HIGH
PRESSURE DEVELOPS OVER FLORIDA AS THE BERMUDA HIGH EXTENDS WESTWARD
FROM SUNDAY THROUGH TUESDAY. THIS IS FORECAST TO BRING A MORE
TYPICAL SUMMER PATTERN OF AFTERNOON AND EVENING CONVECTION DRIVEN BY
SEA BREEZE BOUNDARIES. FOR MONDAY AND TUESDAY IT CAN BE SEEN IN THE
SOUNDING FORECASTS AND NEMS GFS AND NRL AEROSOL MODELS THE PRESENCE
OF SOME SAHARAN DUST. FOR WEDNESDAY, THE SUBTROPICAL HIGH PRESSURE
STRENGHTENS IN THE MIDDLE PORTIONS OF THE ATLANTIC OCEAN CAUSING THE
TROUGH OVER THE EASTERN PORTIONS OF THE US TO AMPLIFY. THIS IS
EXPECTED TO COOL SOMEWHAT THE MID LEVEL TEMPERATURES WHICH COULD
POTENTIALLY INCREASE THE CONVECTION BY MID WEEK. THE COMBINATION OF
WEAK SOUTHWESTERLY FLOW AND A LITTLE BIT MORE MOISTURE IS EXPECTED TO
INCREASE THE SHOWERS AND THUNDERSTORMS OVER THE NORTHERN AND EASTERN
SECTIONS OF SOUTH FLORIDA, THE LAKE REGION AND IN GENERAL PALM BEACH
AND BROWARD COUNTIES.
BETWEEN WEDNESDAY AND FRIDAY THE EAST COAST TROUGH WEAKENS GRADUALLY
BUT IT STILL SHOWS A GENERAL WEAKNESS OVER FLORIDA. FOR FRIDAY, THE
RIDGE OVER NORTHERN MEXICO EXPANDS EASTWARD INCREASING THE 500 MB
TEMPERATURES OVER NORTH FLORIDA AND SOUTH GEORGIA TO -4C. FOR SOUTH
FLORIDA WE STAY IN THE -6 RANGE WHICH IS VERY UNFAVORABLE FOR ANY
WIDESPREAD CONVECTION TO OCCUR.
THE RISK OF RIP CURRENTS WILL BE SLIGHT FOR THE ATLANTIC BEACHES FOR
SUNDAY.
MARINE...
GENERAL EAST TO SOUTHEAST WIND IS EXPECTED THROUGH TUESDAY AT SPEEDS
OF LESS THAN 10 TO 12 KNOTS OUTSIDE OF SCATTERED SHOWERS
/THUNDERSTORMS. THE WIND WILL BEGIN TO VEER TO A SOUTH OR SOUTHWEST
DIRECTION LATER IN THE WEEK AS THE SURFACE RIDGE SHIFTS TO THE SOUTH
AND THE EAST COAST AMPLIFIES DUE TO A BLOCKING HIGH IN THE
ATLANTIC.
FIRE WEATHER...
NO FIRE WEATHER CONCERNS OR FOG IS ANTICIPATED THROUGHOUT THE
FORECAST PERIOD. THE TYPICAL AREA WITH LOWER RELATIVE HUMIDITIES,
GLADES AND HENDRY, WILL MAINTAIN VALUES ABOVE 50 PERCENT THIS
WEEKEND AND COMING WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 89 76 88 76 / 20 20 30 10
FORT LAUDERDALE 89 79 89 78 / 20 20 30 10
MIAMI 90 77 88 77 / 20 20 20 10
NAPLES 90 75 89 75 / 20 10 20 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
743 AM EDT SUN JUL 21 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 450 AM EDT SUN JUL 21 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A ZONAL FLOW OVER THE UPPER
GREAT LAKES. AT THE SFC...HIGH PRESSURE DOMINATES THE UPPER GREAT
LAKES. THE CLEAR SKIES AND LIGHT WINDS HAVE ALLOWED TEMPS EARLY THIS
MORNING TO FALL INTO THE 40S WITH EVEN A FEW LOCATIONS REACHING THE
MID TO UPPER 30S.
TODAY...AS THE SFC HIGH SHIFTS EAST OF THE AREA...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 INDICATE SOME INCREASE IN 305K ISENTROPIC ASCENT OVER FAR WRN
UPR MI LATE IN THE DAY ALTHOUGH BEST MOISTURE LIFT SHOULD STAY SOUTH
AND WEST. WILL MAINTAIN GOING FCST OF SLIGHT CHANCE POPS OVER THE
FAR WEST.
TONIGHT...INCREASING 925-700 MB THETA-E ADVECTION AND 305K
ISENTROPIC ASCENT SHOULD LEAD TO INCREASED CHCS FOR SHRA AND TSRA
ESPECIALLY AFT MIDNIGHT AS SHORTWAVE APPROACHED FM THE WEST.
LIMITING FACTOR FOR TSRA WILL BE LACK OF ELEVATED INSTABILITY AS
MUCAPES ONLY A FEW HUNDRED J/KG. WILL KEEP HIGHER CHC POPS OVER FAR
WEST AND TAPER TO LOW CHC 20-30 PCT POPS OVER CENTRAL COUNTIES.
EXPECT LOWS GENERALLY IN THE 50S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 450 AM EDT SUN JUL 21 2013
MOST TIME SPENT ON LONG TERM WAS WITH PRECIP CHANCES MON/MON NIGHT
AND ASSESSING SEVERE STORM THREAT FOR MON AFTERNOON/EVENING.
LOOKING FIRST AT THE LARGE SCALE...AN UPPER TROUGH OVER THE ERN HALF
OF THE CONUS WILL BE STEMMING FROM A CLOSED LOW OVER NRN QUEBEC AND
AN UPPER RIDGE WILL BE OVER THE WRN CONUS AT 12Z MON. A PIECE OF
UPPER ENERGY WILL MOVE ACROSS THE REGION MON INTO EARLY MON
NIGHT...FOLLOWED BY OTHER SMALLER SCALE ENERGY THU NIGHT THROUGH
SAT...BUT THE OVERALL PATTERN REMAINS SIMILAR THROUGH THE EXTENDED.
THIS MEANS...FOR THE MOST PART...THAT COOLER WEATHER IS HERE TO STAY
FOR MUCH OF THE NEXT WEEK AT LEAST.
FOR THE SPECIFICS...
MON/MON NIGHT...THERE WILL BE PRECIP MOVING INTO THE WRN CWA EARLY
MON AS THE UPPER TROUGH AND SFC TROUGH/COLD FRONT MOVE IN. THINK THE
BEST PRECIP CHANCES WILL BE DURING THE AFTERNOON/EARLY EVENING AS
THE COLD FRONT MOVES THROUGH A POTENTIALLY UNSTABLE AIRMASS.
QUESTIONS IS HOW MUCH CLEARING WILL RESULT AFTER MORNING
RAIN...WHICH WILL EFFECT HOW MUCH INSTABILITY EXISTS IN THE
AFTERNOON. IF WE CAN GET GOOD CLEARING...SBCAPE VALUES MAY BE
800-1200J/KG /HIGHEST OVER SCENTRAL UPPER MI/...AND STRONGLY VEERING
WINDS THROUGH THE ATMOSPHERE WILL LEAD TO AROUND 40KTS OF 0-6KM BULK
SHEAR. IF OPTIMAL CONDITIONS FOR CONVECTION DO MATERIALIZE...THEN
SEVERE THUNDERSTORMS WITH LARGE HAIL AND DAMAGING WINDS WOULD BE
POSSIBLE...WITH THE BEST CHANCES OVER SCENTRAL UPPER MI.
HOWEVER...AT THIS TIME...THINK THE COVERAGE OF ANY SEVERE WEATHER
WILL BE MORE LIMITED DUE TO DRY AIR. FOR NOW WILL CONTINUE MENTION
OF SEVERE CHANCES IN HWO/EHWO BUT STILL TOO UNCERTAIN TO PUT IN
GRIDS. MON LOOKS LIKE THE WARMEST DAY IN THE NEXT WEEK AHEAD OF THE
COLD FRONT...WITH HIGHS IN THE 70S TO MID 80S.
POSTFRONTAL TUESDAY SHOULD BE COOLER AND SIMILAR TO YESTERDAY...WITH
HIGHS AROUND 60 NEAR LAKE SUPERIOR TO THE LOW 70S SOUTH CENTRAL.
SKIES SHOULD BE CLEARING BY THE AFTERNOON.
WED WILL BE SLIGHTLY WARMER THAN TUESDAY AS TEMPS RECOVER SOME FROM
THE COLD FRONT. SHOULD SEE SOME INCREASE IN CLOUDS FROM W TO E
DURING THE AFTERNOON/EVENING AS A MORE MILD PIECE OF UPPER ENERGY
SLIDES ACROSS THE CWA...BUT NO PRECIP IS EXPECTED.
THERE IS MORE UNCERTAINTY LATER IN THE WEEK WHEN LOOKING AT MORE
SIGNIFICANT UPPER ENERGY SLIDING INTO THE REGION...BUT PRECIP WILL
CERTAINLY BE POSSIBLE LATER INTO THE WEEK. TEMPERATURES WILL CLIMB
ANOTHER COUPLE OF DEGREES ON THURSDAY...BUT SHOULD AGAIN FALL INTO
THE WEEKEND AS THE UPPER TROUGH MOVES OVERHEAD. USED A GENERAL
CONSENSUS OF MODEL GUIDANCE FOR THIS PART OF THE FORECAST.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 729 AM EDT SUN JUL 21 2013
VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD. EXPECT INCREASING
MID CLOUDS LATE IN THE DAY AND TONIGHT AHEAD OF AN APPROACHING LOW
PRESSURE SYSTEM. SOME SHRA ARE POSSIBLE AT KIWD AND KCMX LATE
TONIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 450 AM EDT SUN JUL 21 2013
HIGH PRESSURE WILL KEEP WINDS GENERALLY LIGHT TODAY OVER THE
NORTHERN GREAT LAKES. SRLY WINDS WILL INCREASE TO AROUND 20 KNOTS
LATE TONIGHT AND MONDAY AHEAD OF A LOW PRESSURE TROUGH MOVING
THROUGH THE AREA. NORTH TO NORTHWEST WINDS WILL THEN INCREASE TO 20
KNOTS BY LATE MONDAY NIGHT INTO TUESDAY BEHIND THE TROUGH/COLD FRONT
MOVING THROUGH THE REGION. WINDS ARE THEN EXPECTED TO REMAIN BELOW
20 KNOTS TUE NIGHT THROUGH THURSDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...TITUS
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
1028 AM CDT SUN JUL 21 2013
.UPDATE...
MAKING SOME ADJUSTMENTS TO THE FORECAST FOR THE FIRST COUPLE OF
PERIODS...INCLUDING ADJUSTING POPS A LITTLE FOR TODAY...CUTTING POPS
FOR TONIGHT...AND TWEAKING TEMPS UP A HAIR FOR THIS AFTERNOON.
&&
.SHORT TERM...
WATER VAPOR AND RUC STREAMLINE ANALYSIS SHOW REMNANT UPPER LEVEL LOW
CURRENTLY OVER THE LOWER DELTA REGION. SHORT TERM MODELS SHOW THIS
LOW OPENING UP AND DRIFTING EAST TODAY. BLENDED TOTAL PW PRODUCT
SHOWS BEST DEEP MOISTURE OVER S/E AREAS AHEAD OF UPPER LOW...BUT EVEN
RIGHT UNDER THE UPPER LOW WHERE A MIN IN MOISTURE EXISTS...PW VALUES
STILL AROUND 1.8 INCHES. CU IS BEGINNING TO FORM ACROSS THE
AREA...AND WITH CONTINUED HEATING AND SUPPORT FROM UPPER SYSTEM
EXPECT CONVECTIVE COVERAGE TO INCREASE THROUGH THE AFTERNOON. SHORT
TERM MESOSCALE MODELS AGREE ON BEST COVERAGE OVER S/E AREAS...AND
THIS GENERALLY SEEMS SUPPORTED BY LATEST TRENDS IN OBSERVATIONAL
DATA. DID TWEAK POPS UP A HAIR TO GET ALL AREAS TO AT LEAST 30 PCT
BUT OVERALL TREND OF GOING FORECAST LOOKS OK. MORNING SOUNDING
ANALYSIS AND LOCAL RUC MICROBURST PARAMETER SUGGEST THAT CURRENT
WORDING IN HWO AND GRAPHICAST OF SOME STRONG STORMS SEEMS REASONABLE.
RUC SHOWS 500 MB TEMPS COOLING A DEG OR TWO MOST OF AREA AS MID LEVEL
COLD POOL WITH UPPER LOW MOVES ACROSS...AND THIS SHOULD HELP ENHANCE
INSTABILITY AND LAPSE RATES A BIT. THUS WOULD CERTAINLY NOT RULE OUT
A COUPLE OF SEVERE STORMS THIS AFTERNOON...PARTICULARLY WITH ANY
CELL/BOUNDARY MERGERS. WITH PRETTY COMPLETE LACK OF CLOUDINESS BEFORE
BUILDING CU...TEMPS HAVE WARMED QUITE QUICKLY THIS MORNING. ADJUSTED
DIURNAL CURVE FOR MORE RAPID WARMUP AND TWEAKED MAXES UP A DEG OR
TWO.
WITH REGARD TO TONIGHT...THINKING THAT 00Z GFS MAY HAVE BEEN A WET
ANOMALY BASED ON GEFS GUIDANCE...LATEST 06Z GFS...AND 00Z ECMWF. MAIN
CONCERN FOR CONVECTION TONIGHT IS LIKELY WAVE THAT HAS BEEN PRODUCING
SOME CONVECTION OVER NE OK THIS MORNING...AND IT IS CERTAINLY
PLAUSIBLE THAT THIS SYSTEM COULD INCITE SOME OVERNIGHT CONVECTION
ESPECIALLY OVER NORTHERN AREAS. HOWEVER...HIGH CHANCE TO CATEGORICAL
POPS IN CURRENT FORECAST AS PROVIDED BY 00Z GFS SEEM A BIT
BULLISH...AND WILL REDUCE POPS BY 15-30 PCT AREA WIDE FOR TONIGHT.
&&
.AVIATION...
VFR CONDITIONS WERE BEING OBSERVED AT 14Z AND WILL PREVAIL AT ALL
SITES THROUGH 18Z. MODELS INDICATE GREATEST COVERAGE OF TSTMS THIS
AFTN/EVNG WL BE ACROSS THE SRN HALF OF THE AREA. BRIEF IFR CONDITIONS
CAN BE EXPECTED AROUND THE STORMS FROM 18Z-04Z. VFR CONDITIONS WL
RESUME AREAWIDE THIS EVNG AND CONTINUE THROUGH 09Z MON. AFTER
09Z...MVFR VSBYS WL BE PSBL MAINLY ACROSS THE SRN HALF OF THE AREA.
CONVECTION MAY GET AN EARLY START ACROSS THE NORTH MONDAY MORNING DUE
TO A DISTURBANCE IN THE NW FLOW ALOFT. /22/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 93 72 90 75 / 31 43 55 36
MERIDIAN 92 72 91 72 / 40 47 62 45
VICKSBURG 94 74 92 73 / 32 44 49 29
HATTIESBURG 92 73 92 74 / 45 27 64 42
NATCHEZ 93 74 90 75 / 44 27 53 27
GREENVILLE 95 74 92 76 / 31 58 52 39
GREENWOOD 94 72 91 75 / 30 57 56 44
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
AEG/MME
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1019 AM CDT SUN JUL 21 2013
.UPDATE...
UPDATED TO ADJUST MORNING AND AFTERNOON POPS
&&
.DISCUSSION...
12Z UPPER AIR ANALYSIS INDICATED THAT A SEASONABLY STRONG
SHORTWAVE TROUGH EXTNDD FM WRN MN INTO CNTRL NEB. THIS WAS
SPREADING LARGE-SCALE ASCENT ACROSS THE FA THIS MORNING. THE 12Z
KOAX RAOB INDCD AROUND 1400 J/KG OF MUCAPE WITH LITTLE CAPPING.
THUS THE COMBINATION OF THE FORCING AND WEAKLY CAPPED ATMOSPHERE
WAS LEADING TO SCT TSRA OVER FAR SE NEB AND SW IA. THIS SHOULD
CONT TO SHIFT EWD THIS MORNING ASSOCIATED WITH THE SHORTWAVE
TROUGH. WHAT HAPPENS IN THE WAKE OF THIS MORNING ACTIVITY IS A BIT
UNCLEAR. MODIFYING THE 12Z SOUNDING YIELDS LITTLE CAPPING AS
TEMPERATURES CLIMB INTO THE MID 80S WITH AROUND 2000 J/KG OF
MLCAPE. THE NEGATIVE THOUGH IS THE SUBSIDENCE THAT WILL BE SPREADING
INTO THE AREA LATER THIS MORNING IN THE WAKE OF THE MORNING
SHORTWAVE TROUGH. THIS IS LIKELY TO COMBINE WITH A LACK OF A SFC
BOUNDARY TO FOCUS CONVERGENCE TO MAKE REDEVELOPMENT THIS AFTERNOON
PRETTY UNLIKELY. WILL MAINTAIN A SCHC OF AFTERNOON STORMS OVER
THE ERN FA OTHERWISE WE FEEL IT WILL BE A PRETTY DRY AFTERNOON.
THE OTHER ELEMENTS OF THE FORECAST APPEAR ON TRACK ATTM.
&&
.PREV DISCUSSION... /ISSUED 611 AM CDT SUN JUL 21 2013/
AVIATION...
12Z TAFS FOR KOFK...KLNK AND KOMA.
FOR THE MAJORITY OF THE TAF PERIOD WE EXPECT VFR FLIGHT CONDITIONS
AND RELATIVELY QUIET WEATHER. THE FORECAST CHALLENGE IS PREDICTING
WHEN AND WHERE SHOWERS AND THUNDERSTORMS MIGHT DEVELOP AND
CONSEQUENTLY EFFECT THE TAF SITES. THIS TIME OF YEAR...IN THESE
WEATHER PATTERNS...THE PREDICTABILITY OF CONVECTION IS LOW AND THE
UNCERTAINTY IS HIGH. GIVEN THAT...WILL KEEP SPECIFIC MENTION OF
TSRA OUT OF THE TAFS FOR NOW AND REFINE AS THE PATTERN BECOMES MORE
SUPPORTIVE OF THUNDERSTORM DEVELOPMENT.
THERE IS ONE CLUSTER OF SHOWERS AND THUNDERSTORMS CURRENTLY MOVING
THROUGH WESTERN NEBRASKA AND INTO CENTRAL NEBRASKA...BUT AT THIS
TIME THAT AREA APPEARS TO BE MOVING INTO SOUTH CENTRAL NEBRASKA AND
WILL NOT MOVE FAR ENOUGH EAST TO EFFECT THE TAF SITES. ADDITIONAL
STORM DEVELOPMENT COULD OCCUR IN EASTERN NEBRASKA THIS AFTERNOON.
NIETFELD
PREV DISCUSSION... /ISSUED 301 AM CDT SUN JUL 21 2013/
DISCUSSION...
FORECASTING AREAL EXTENT OF CONVECTION THROUGH THE
FORECAST WILL BE A SIGNIFICANT CHALLENGE AS THE REGION REMAINS IN
NORTHWEST FLOW THIS WEEK.
FIRST ROUND OF CONVECTION IS MOVING INTO EASTERN NEBRASKA EARLY
THIS MORNING...BUT WILL ALSO HAVE TO OVERCOME A POCKET OF DRY AIR
AT H85. CONTINUED THETAE ADVECTION SHOULD HELP TO ERODE THIS DRY
POCKET AND CONTINUE TRIGGER STORMS THIS MORNING THAT WILL
CONTINUE TO MOVE EASTWARD THROUGH THE AREA INTO WESTERN IOWA
BEFORE DISSIPATING THROUGH MID TO LATE MORNING. WHILE HEAVY RAINS
ARE NOT WIDESPREAD...SOME VERY SPOTTY LOCATIONS WHERE LIGHTNING IS
OCCURRING ARE LIKELY PICKING UP SOME DECENT MEANINGFUL RAINFALL.
MEANWHILE...WATER VAPOR IMAGERY INDICATES ANOTHER SUBTLE WAVE IS
LIKELY MOVING THROUGH WESTERN SOUTH DAKOTA. ANOTHER CLUSTER OF
STORMS HAS REFIRED ACROSS THAT AREA...MOVING INTO NORTH CENTRAL
NEBRASKA. BOTH THE NAM AND RAP SEEM TO HAVE PICKED UP ON THIS
FEATURE AND MOVE IT THROUGH THE FORECAST AREA THIS AFTERNOON...WHICH
COULD BE THE TRIGGER FOR ADDITIONAL STORMS AS WE HEAD THROUGH PEAK
HEATING. FORWARD SPEED SUGGESTS THAT THIS MAY MOSTLY BE OUT OF THE
AREA BY EARLY THIS EVENING.
THE REMAINDER OF SUNDAY NIGHT AND MONDAY MORNING SHOULD BE DRY. A
FRONTAL BOUNDARY MOVING INTO THE REGION COULD TRIGGER ISOLATED
AFTERNOON STORMS IN NORTHEAST NEBRASKA. TEMPS AHEAD OF THE FRONT
WILL PROBABLY REACH THE LOWER 90S ONCE AGAIN. SHOULD ALSO SEE A
CHANCE OF THUNDERSTORMS MONDAY NIGHT AS THE FRONT MOVES THROUGH
THE AREA.
THE NEXT WAVE APPEARS ON THE HORIZON BY TUESDAY AFTERNOON THEN
MOVES THROUGH THE REGION TUESDAY NIGHT. WEDNESDAY AND WEDNESDAY
NIGHT SHOULD BE DRY...BUT ANOTHER WAVE MOVES INTO THE AREA ON
THURSDAY AND LINGERS THROUGH FRIDAY. THE GFS SUGGESTS THAT WE
MIGHT REMAIN DRY ON SATURDAY...BUT THE ECMWF HAS YET ANOTHER SURGE
OF MOISTURE MOVING THROUGH. NEVERTHELESS...CONFIDENCE DECREASES IN
SPECIFICS TOWARD THE END OF THE WEEK.
DEWALD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
611 AM CDT SUN JUL 21 2013
.AVIATION...
12Z TAFS FOR KOFK...KLNK AND KOMA.
FOR THE MAJORITY OF THE TAF PERIOD WE EXPECT VFR FLIGHT CONDITIONS
AND RELATIVELY QUIET WEATHER. THE FORECAST CHALLENGE IS PREDICTING
WHEN AND WHERE SHOWERS AND THUNDERSTORMS MIGHT DEVELOP AND
CONSEQUENTLY EFFECT THE TAF SITES. THIS TIME OF YEAR...IN THESE
WEATHER PATTERNS...THE PREDICTABILITY OF CONVECTION IS LOW AND THE
UNCERTAINTY IS HIGH. GIVEN THAT...WILL KEEP SPECIFIC MENTION OF
TSRA OUT OF THE TAFS FOR NOW AND REFINE AS THE PATTERN BECOMES MORE
SUPPORTIVE OF THUNDERSTORM DEVELOPMENT.
THERE IS ONE CLUSTER OF SHOWERS AND THUNDERSTORMS CURRENTLY MOVING
THROUGH WESTERN NEBRASKA AND INTO CENTRAL NEBRASKA...BUT AT THIS
TIME THAT AREA APPEARS TO BE MOVING INTO SOUTH CENTRAL NEBRASKA AND
WILL NOT MOVE FAR ENOUGH EAST TO EFFECT THE TAF SITES. ADDITIONAL
STORM DEVELOPMENT COULD OCCUR IN EASTERN NEBRASKA THIS AFTERNOON.
NIETFELD
&&
.PREV DISCUSSION... /ISSUED 301 AM CDT SUN JUL 21 2013/
.DISCUSSION...
FORECASTING AREAL EXTENT OF CONVECTION THROUGH THE
FORECAST WILL BE A SIGNIFICANT CHALLENGE AS THE REGION REMAINS IN
NORTHWEST FLOW THIS WEEK.
FIRST ROUND OF CONVECTION IS MOVING INTO EASTERN NEBRASKA EARLY
THIS MORNING...BUT WILL ALSO HAVE TO OVERCOME A POCKET OF DRY AIR
AT H85. CONTINUED THETAE ADVECTION SHOULD HELP TO ERODE THIS DRY
POCKET AND CONTINUE TRIGGER STORMS THIS MORNING THAT WILL
CONTINUE TO MOVE EASTWARD THROUGH THE AREA INTO WESTERN IOWA
BEFORE DISSIPATING THROUGH MID TO LATE MORNING. WHILE HEAVY RAINS
ARE NOT WIDESPREAD...SOME VERY SPOTTY LOCATIONS WHERE LIGHTNING IS
OCCURRING ARE LIKELY PICKING UP SOME DECENT MEANINGFUL RAINFALL.
MEANWHILE...WATER VAPOR IMAGERY INDICATES ANOTHER SUBTLE WAVE IS
LIKELY MOVING THROUGH WESTERN SOUTH DAKOTA. ANOTHER CLUSTER OF
STORMS HAS REFIRED ACROSS THAT AREA...MOVING INTO NORTH CENTRAL
NEBRASKA. BOTH THE NAM AND RAP SEEM TO HAVE PICKED UP ON THIS
FEATURE AND MOVE IT THROUGH THE FORECAST AREA THIS AFTERNOON...WHICH
COULD BE THE TRIGGER FOR ADDITIONAL STORMS AS WE HEAD THROUGH PEAK
HEATING. FORWARD SPEED SUGGESTS THAT THIS MAY MOSTLY BE OUT OF THE
AREA BY EARLY THIS EVENING.
THE REMAINDER OF SUNDAY NIGHT AND MONDAY MORNING SHOULD BE DRY. A
FRONTAL BOUNDARY MOVING INTO THE REGION COULD TRIGGER ISOLATED
AFTERNOON STORMS IN NORTHEAST NEBRASKA. TEMPS AHEAD OF THE FRONT
WILL PROBABLY REACH THE LOWER 90S ONCE AGAIN. SHOULD ALSO SEE A
CHANCE OF THUNDERSTORMS MONDAY NIGHT AS THE FRONT MOVES THROUGH
THE AREA.
THE NEXT WAVE APPEARS ON THE HORIZON BY TUESDAY AFTERNOON THEN
MOVES THROUGH THE REGION TUESDAY NIGHT. WEDNESDAY AND WEDNESDAY
NIGHT SHOULD BE DRY...BUT ANOTHER WAVE MOVES INTO THE AREA ON
THURSDAY AND LINGERS THROUGH FRIDAY. THE GFS SUGGESTS THAT WE
MIGHT REMAIN DRY ON SATURDAY...BUT THE ECMWF HAS YET ANOTHER SURGE
OF MOISTURE MOVING THROUGH. NEVERTHELESS...CONFIDENCE DECREASES IN
SPECIFICS TOWARD THE END OF THE WEEK.
DEWALD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1035 AM EDT SUN JUL 21 2013
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL SLOWLY AMPLIFY OVER THE REGION THROUGH
EARLY IN THE WEEK. MEANWHILE...A SURFACE TROUGH OF LOW PRESSURE
WILL REMAIN OVER THE AREA THROUGH MID TO LATE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1035 AM SUNDAY...
THE LATEST SURFACE ANALYSIS CONTINUED TO SHOW A WEAK GRADIENT OVER
CENTRAL NORTH CAROLINA...WITH A PERSISTENT SURFACE TROUGH WEST OF
THE YADKIN RIVER. THE MORNING UPPER-LEVEL ANALYSES SHOWED A FAIRLY
PRONOUNCED 850MB TROUGH OVER CENTRAL NORTH CAROLINA...CAPTURED BY
THE RUC AND FORECAST TO LINGER OVER THE AREA WHILE WEAKENING THROUGH
THE AFTERNOON. ON WATER VAPOR...IT SEEMED AS IF CENTRAL NORTH
CAROLINA WAS IN ALMOST SUBTLE RIDGING BETWEEN A WEAK UPPER LOW OVER
THE SOUTHERN MISSISSIPPI RIVER AND A WEAK WAVE MOVING EAST ACROSS
THE STATE.
IT WAS INTERESTING TO NOTE THAT THE PRECIPITABLE WATER VALUE ON THE
KRNK SOUNDING WAS BELOW 1.4 INCHES THIS MORNING. IT WAS HIGHER AT
KGSO COMPARED TO 12Z SATURDAY. DOWNDRAFT CAPE ON THE SPC
MESOANALYSIS WAS WEAKER THAN SATURDAY...AND OTHER PARAMETERS SUCH AS
THE MID-LEVEL LAPSE RATES AND THETA-E DIFFERENCE ALOFT WERE SLIGHTLY
LESS AS WELL. THE LATEST RUC FORECASTS NOTICEABLE 850MB SUBSIDENCE
OVER CENTRAL NORTH CAROLINA FOR THE AFTERNOON...WITH SOMEWHAT BETTER
LIFT MOVING IN OVER THE NORTHWEST PIEDMONT AND THE SANDHILLS LATE
TODAY AND THIS EVENING.
MOST OF THE CONVECTIVE-ALLOWING MODELS DEVELOP SCATTERED SHOWERS AND
THUNDERSTORMS OVER CENTRAL NORTH CAROLINA THIS AFTERNOON...AND FOR
THE MID-MORNING UPDATE OPTED TO CONCENTRATE THE BETTER CHANCES OVER
THE NORTHWEST PIEDMONT...NEAR WHAT MAY END UP BEING SOME
DIFFERENTIAL HEATING BASED ON THE LATEST VISIBLE IMAGES. A STORM OR
TWO COULD BECOME STRONG...BUT THE PREPONDERANCE OF THE CURRENT
EVIDENCE SUGGESTS THE POTENTIAL FOR A SEVERE STORM IS LIMITED. WILL
REVIEW LATER DATA TO TRY TO FOCUS BETTER CHANCES FOR THIS EVENING...
AS BASED ON THE LATEST RUC THIS WOULD BE MAINLY NORTH OF U.S. 64 AND
OVER THE SANDHILLS WHERE THE GREATER 850MB LIFT IS CONCENTRATED.
KEPT HIGH TEMPERATURES AS IS GIVEN AT LEAST SOME EXPECTED SUN...
THOUGH HIGHS ARE FORECAST BELOW FULL SUN 1000-850MB THICKNESS VALUES
WHICH WOULD SUGGEST HIGHS A CATEGORY WARMER. LOWS TONIGHT IN THE
LOWER 70S.
&&
.SHORT TERM /MONDAY AND MONDAY NIGHT/...
AS OF 300 AM SUNDAY...
WEAK SHORT-WAVE ENERGY CURRENTLY OVER THE NORTHERN PLAINS WILL
UNDERGO SLIGHT AMPLIFICATION(ALONG WITH AMPLIFICATION OF THE LONG
WAVE TROUGH AS WELL)AS IT PROGRESSES EAST-SOUTHEASTWARD INTO THE
OHIO AND TN VALLEY ON MONDAY...REACHING THE CENTRAL-SOUTHERN BY
DAYBREAK TUESDAY. IN RESPONSE TO THE ATTENDANT UPSTREAM HEIGHT FALLS
ON THE ORDER OF 20 TO 30 METERS...A WEAK WAVE OF LOW PRESSURE IS
FORECAST TO DEVELOP ALONG THE SURFACE TROUGH OF LOW PRESSURE
BISECTING THE VIRGINIAS AND CAROLINAS...WHICH WILL SERVE TO
STRENGTHEN THE LOW-LEVEL MOISTURE CONVERGENCE AS A POOL OF +2.0
PWATS RESIDES OVER THE SOUTHEASTERN STATES. ADDITIONALLY...THERE IS
ALSO THE POTENTIAL THAT REMNANT CENTER ASSOCIATED WITH THE WEAK
UPPER LOW CURRENTLY OVER LOUISIANA COULD MOVE NORTHEASTWARD OVER THE
AREA LATE MONDAY AND INTO MONDAY NIGHT...FURTHER AUGMENTING ASCENT
OVER THE AREA. AS SUCH...CONVECTION MONDAY AFTERNOON IS EXPECTED TO
BE MORE ROBUST THAN IN PREVIOUS DAYS...WITH THE THREAT OF CONVECTION
PERSISTING THROUGH THE OVERNIGHT HOURS.
CONFIDENCE IN THE TIMING/IMPACTS OF THIS DISTURBANCE IS LOW AT THIS
POINT...ESPECIALLY WITH THE 00Z/21 GFS COMPLETELY SHEARING THE
DISTURBANCE COMPLETING APART OVER GEORGIA/SC. HOW THIS FEATURES
EVOLVES WILL LIKELY BE THE DIFFERENCE BETWEEN LIKELY OR CHANCE POPS
ACROSS CENTRAL NC MONDAY AFTERNOON/EVENING.
HIGH +2.0 PWATS COULD RESULT IN ONE OR TWO WET MICROBURSTS...MAINLY
DURING PEAK AFTERNOON HEATING/DESTABILIZATION...WITH A MORE
ORGANIZED SEVERE THREAT BEING IMPEDED BY WEAK SHEAR AND WEAK
MID-LEVEL LAPSE RATES. ALSO...WITH LOCAL RIVER....STREAMS AND CREEKS
STILL RUNNING HIGH...FLASH FLOODING WILL ALSO BE POSSIBLE.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 245 AM SUNDAY...
TUESDAY AND TUESDAY NIGHT:
WITH THE PERSISTENT SOUTHWEST FLOW...THE ATMOSPHERE WILL REMAIN
SUFFICIENTLY MOIST AND UNSTABLE. THE SURFACE TROUGH IS EXPECTED TO
STALL OVER THE MID ATLANTIC...WITH THE UPPER LEVEL TROUGH SLOWLY
DRIFTING EAST OVER THE AREA. THE 00Z RUN OF THE GFS PICKS UP ON A H3
DISTURBANCE MOVING THROUGH NC TUESDAY AFT/EVE...WHICH SHOULD HELP
ENHANCE THE DIURNALLY DRIVEN CONVECTION. BEST LIFT WILL TRANSLATE
FROM NW TO SE THROUGH CENTRAL NC AHEAD OF THE BACKDOOR COLD
FRONT...WHICH WPC PREDICTS WILL MOVE TROUGH THE AREA TUESDAY NIGHT
AND INTO WEDNESDAY...POTENTIALLY STALLING ALONG THE COAST. AS
SUCH...WILL SHOW BEST CHANCES FOR CONVECTION FROM THE TRIANGLE SE
BETWEEN 18Z TUESDAY AND 06Z WEDNESDAY. HIGH TEMPS IN THE UPPER 80S
TO LOW 90S AND OVERNIGHT LOWS IN THE LOW TO MID 70S EXPECTED.
WEDNESDAY THROUGH SATURDAY:
LOW LEVEL WINDS MAY TEMPORARILY BECOME MORE WNW BEHIND THE BACKDOOR
FRONT SHOULD IT INDEED MOVE THROUGH THE AREA AND STALL ALONG THE
COAST BY WEDNESDAY...WHICH WOULD YIELD A SUBSEQUENT DRYING OF THE
MID LEVELS. CURRENT MODEL AGREEMENT WITH REGARD TO THE TROUGH...AT
BOTH THE SURFACE AND ALOFT...LINGERING OVER THE AREA THROUGH THE END
OF THE WEEK IS GOOD. THE LOCATION OF THE TROUGH AXIS WILL PLAY A
ROLE IN WHERE THE BEST MOISTURE IS AVAILABLE...WHICH CURRENTLY IS
EXPECTED ALONG THE COAST. DEPENDING ON THEIR TIMING...A SERIES OF
UPPER LEVEL DISTURBANCES MOVING OVER THE AREA COULD ENHANCE DIURNAL
CONVECTIVE ACTIVITY THROUGH THE PERIOD. OF LESSER CERTAINTY IS THE
COVERAGE AND LOCATION OF THE ANTICIPATED AFT/EVE SHOWERS AND STORMS.
FOR NOW WILL CONTINUE TO INDICATE BEST PRECIP CHANCES DURING THE
AFT/EVE HOURS ACROSS THE AREA...WITH SLIGHTLY HIGHER CHANCES ACROSS
THE EAST WHERE THE BEST MOISTURE IS EXPECTED. ONLY SMALL CHANGES IN
TEMPS FROM DAY TO DAY THROUGH THE PERIOD...HIGHS MAINLY IN THE MID
80S TO AROUND 90 DEGREES WITH OVERNIGHT LOWS MAINLY IN THE UPPER 60S
TO LOW 70S.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
AS OF 1035 AM SUNDAY...
24-HR TAF PERIOD:
MVFR CEILINGS WILL LIFT SLOWLY...EVENTUALLY BECOMING MOSTLY VFR BY
AFTERNOON. DIURNAL SCATTERED SHOWERS AND STORMS WILL BE POSSIBLE AT
ALL TAF SITES THIS AFTERNOON MAINLY FROM 20Z-02Z. -CBL/DJF
LOOKING AHEAD:
EXPECT AN ABOVE NORMAL CHANCE FOR SHOWERS AND THUNDERSTORMS MONDAY
THROUGH THURSDAY AS A SLOW MOVING UPPER LEVEL TROUGH DEVELOPS OVER
THE EASTERN UNITED STATES. THOUGH CONVECTION WILL BE POSSIBLE DURING
THE DAY AND AT NIGHT...THE BEST CHANCE EACH DAY WILL BE IN THE
TYPICAL 18-03Z TIME FRAME. SUB-VFR CONDITIONS ASSOCIATED WITH FOG OR
STRATUS WILL BE POSSIBLE EACH MORNING...PRIMARILY IN THE 08-14Z TIME
FRAME. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CBL
NEAR TERM...CBL/DJF
SHORT TERM...CBL
LONG TERM...KMC
AVIATION...CBL/VINCENT/DJF
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
646 AM EDT SUN JUL 21 2013
.SYNOPSIS...
A TYPICAL SUMMER PATTERN OF HIGH PRESSURE OFFSHORE AND A TROUGH
OF LOW PRESSURE INLAND WILL PERSIST THROUGH TUESDAY. A COLD
FRONT WILL APPROACH FROM THE NORTHWEST WEDNESDAY THEN STALL OVER
THE REGION THURSDAY AND FRIDAY BEFORE MOVING OFFSHORE SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 635 AM SUNDAY...BAND OF SHOWERS PASSING SOUTH OF THE CRYSTAL
COAST AND THE BULK OF THE ACTIVITY LOOKS TO REMAIN NEAR THE COAST
OR OFFSHORE THROUGH MIDDAY AS MID-LEVEL ENERGY HAS PASSED TO OUR
NORTHEAST. THE 3 KM HRRR MODEL HAS DONE QUITE WELL WITH THE
PLACEMENT OF THE PRECIPITATION THUS FAR THIS MORNING AND PER THE
LATEST HRRR WITH AGREEMENT FROM THE RAP...EXPECT SCATTERED SHOWERS
AND THUNDERSTORMS TO REDEVELOP INLAND BY AROUND 18Z AND INCREASE
IN COVERAGE THROUGH THE AFTERNOON AND EVENING. POPS RAMP BACK UP
TO 30 TO 50 PCT AT THAT TIME WITH THE HIGHEST VALUES OVER AREAS
WEST OF HIGHWAY 17. WITH PRECIPITABLE WATER VALUES BACK NEAR 2
INCHES...ANY SHOWERS THAT DEVELOP COULD PRODUCE A QUICK DOWNPOUR
OF UP TO AN INCH OR SO. GIVEN MORE CLOUD COVER THAN RECENT
DAYS...MAXIMUM TEMPERATURES SHOULD REMAIN IN THE UPPER 80S FAIRLY
UNIFORM IN THE MIDDLE TO UPPER 80S AREA-WIDE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
AS OF 345 AM SUNDAY...BOTH THE GFS AND NAM SHOW SOME STRONG MID-
LEVEL VORTICITY RIDING UP THE COAST TONIGHT...COUPLED WITH A WEAK
UPPER LEVEL TROUGH SLIDING ACROSS THE REGION. THIS ALONG WITH A
VERY MOIST ATMOSPHERE WILL LEAD TO A CHANCE OF SHOWERS/TSTMS
LINGERING THROUGH THE NIGHT. GIVEN THE TREND FROM THE LAST FEW
NIGHTS...HAVE TRENDED THE BEST PRECIPITATION CHANCES NEAR THE
COAST...WITH LITTLE ACTIVITY INLAND AFTER MIDNIGHT. OVERNIGHT LOWS
TONIGHT SHOULD BE IN THE 73 TO 77 DEGREE RANGE.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
AS OF 315 AM SUN...AN UPPER TROUGH OVER THE GREAT LAKES WILL DIG
SOUTH MON/TUES AND PERSIST OVER THE EASTERN CONUS THROUGH THE LONG
TERM...REINFORCING THE RAIN CHANCES THROUGH THE PERIOD. WEAK
PERTURBATIONS IN THE MID AND UPPER LEVELS WILL ALSO AID IN
DEVELOPING SHOWERS/TSTORMS DURING THE EXTENDED PERIOD...ESPECIALLY
DURING PEAK HEATING HOURS OF THE DAY. AT THE SURFACE...LONG FETCH SW
FLOW WILL TAP TROPICAL MOISTURE FROM THE GULF OF MEXICO AND WESTERN
ATLANTIC MON AND TUES...INCREASING PWATS TO AROUND 2 INCHES. A
WEAK COLD FRONT WILL APPROACH FROM THE NW MON INTO TUES...WHICH
WILL DISSIPATE WEST OF THE REGION PRIOR TO ANOTHER COLD FRONT
APPROACHING FROM THE NW WED INTO THURS. WITH DECENT MODEL
AGREEMENT THROUGH THE EXTENDED...HAVE INDICATED A WEAK FRONTAL
PASSAGE THURS NIGHT WITH BRIEF NORTHERLY FLOW/CAA ON FRI BEFORE
OFFSHORE RIDGE KICKS IN A SW FLOW AGAIN TAKES OVER.
HAVE CONTINUED THE TREND OF DIURNAL CONVECTION EACH DAY THROUGH
THURS WITH 40 TO 50 PERCENT POPS INLAND DURING THE AFTERNOON AND
25-30 PERCENT POPS OVERNIGHT. TRIED TO ADJUST TIMING OF POPS MON
AFTERNOON THROUGH TUES NIGHT TO ALSO COINCIDE WITH THE LOCATION OF
SEVERAL SHORTWAVE VORTMAX ALOFT THAT ROTATE AROUND THE BASE OF
THE BROAD UPPER TROUGH. 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. POPS THURS NIGHT
THROUGH FRI NIGHT REMAIN PINNED NEAR THE COAST WITH SCATTERED
CONVECTION POSSIBLE AGAIN SAT AFTERNOON AS LIGHT SE/S FLOW RETURNS
TO THE AREA. TEMPS THROUGH THE LONG TERM PERIOD WILL BE NEAR CLIMO
WITH HIGHS IN THE UPPER 80S TO NEAR 90 WITH LOW/MID 70S FOR
OVERNIGHT LOWS.
&&
.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
SHORT TERM /TODAY AND TONIGHT/...
AS OF 1250 AM SUN...PER LATEST 11-3.9 MICRON SATELLITE IMAGERY
AND SURFACE OBSERVATIONS...THERE HAVE BEEN SOME MVFR CEILINGS WELL
INLAND AROUND KPGV AND KISO. WITH IMPROVED MIXING...WOULD EXPECT
THESE CEILINGS TO DISSIPATE BY 13Z OR 14Z. EXPECT SCATTERED
SHOWERS AND TSTMS TO DEVELOP BY AROUND 18Z AND CONTINUE INTO EARLY
EVENING WITH A FEW BRIEF REDUCTIONS IN CEILINGS AND VSBY. TONIGHT
WILL MOSTLY BE VFR BECAUSE OF SUFFICIENT WIND...BUT SCATTERED
SHOWERS AND TSTMS COULD AGAIN BRIEFLY LOWER CEILINGS AND VSBYS.
LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 315 AM SUN...SCT THUNDERSHOWERS POSSIBLE EACH DAY FOR THE
TERMINALS WITH MAINLY DRY CONDITIONS AT NIGHT AS PERSISTENT TROUGH
OF LOW PRESSURE REMAINS OVER THE REGION. GENERALLY VFR EXCEPT FOR
TEMPO RESTRICTIONS IN VSBY WITH THE SHOWERS/TSTORMS. 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...ESPECIALLY FOR AREAS THAT
RECEIVE RAINFALL.
&&
.MARINE...
SHORT TERM /TODAY AND TONIGHT/...
AS OF 645 AM SUNDAY...HAVE ALLOWED THE SMALL CRAFT ADVISORY FOR
THE PAMLICO SOUND AND FOR THE COASTAL WATERS NORTH OF OREGON INLET
TO EXPIRE. WINDS ARE AT OR BELOW 20 KNOTS IN THESE LOCATIONS.
THE REMAINDER OF THE SMALL CRAFT ADVISORY REMAINS IN EFFECT INTO
TONIGHT. WINDS ARE CURRENTLY GENERALLY 15 TO 20 KNOTS AND NO BUOY
IS REPORTING MORE THAN 5 FEET NEAR SHORE...ALTHOUGH SOME AREAS ON
THE OUTER WATERS MAY BE AROUND 6 FEET...THUS THE SCA IS MARGINAL
CURRENTLY. HOWEVER...THE GUSTY SW WINDS WILL PERSIST BETWEEN
DEEPENING SURFACE TROUGH OVER THE PIEDMONT AND BERMUDA HIGH
PRESSURE TO THE EAST AND COULD BECOME GUSTY NEAR ANY CONVECTION
DURING THIS AFTERNOON. WINDS AND SEAS SUBSIDE LATER TONIGHT
BEFORE INCREASING AGAIN LATE MONDAY...THUS ANOTHER SCA WILL LIKELY
NEED TO BE ISSUED ONCE CURRENT ADVISORIES EXPIRE.
LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 320 AM SUN...HIGH PRESSURE OFF THE SE COAST WITH A THERMAL
TROUGH INLAND WILL BE THE DOMINANT PATTERN THROUGH MUCH OF THE LONG
TERM. EXPECT A BREAK IN THE GUSTY SW WINDS MON BEFORE REINFORCING
TROUGH/FRONT APPROACH TUES INTO LATE WEEK. MARGINAL SCA CONDITIONS
ARE EXPECTED ONCE AGAIN FROM OREGON INLET SOUTH TUES THROUGH TUES
NIGHT AS THE GRADIENT INCREASES A BIT. NO SIGNIFICANT CHANGES TO
THE MEDIUM AND LONG TERM. WINDS SHOULD BECOME LIGHT LATE IN THE
WEEK AS GRADIENT RELAXES WITH TROUGH AXIS OVER OR JUST EAST OF THE
WATERS.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 AM EDT MONDAY FOR AMZ152-154-156-
158.
&&
$$
SYNOPSIS...CTC
NEAR TERM...CTC
SHORT TERM...CTC
LONG TERM...DAG
AVIATION...CTC/DAG
MARINE...CTC/DAG
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
739 AM CDT SUN JUL 21 2013
.UPDATE...
ISSUED AT 735 AM CDT SUN JUL 21 2013
NO CHANGES NEEDED. LATEST HRRR SHOWS STORM THREAT INTO DVL 23-00Z
THEN SPREADING EAST.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 329 AM CDT SUN JUL 21 2013
HIGH PRESSURE OVER NORTHWESTERN ONTARIO EARLY THIS MORNING WITH A
A CLEAR TO PARTLY CLOUDY SKY OVER MOST OF THE FCST AREA.
EXCEPTIONS ARE AN AREA OF STRATOCU AROUND RUGBY-CANDO NORTHWEST
INTO MANITOBA AND EASTERN SASK AND AN AREA OF MID LEVEL CLOUDS
OVER NE SD INTO CNTRL-SRN MN. A WEAK SHORT WAVE IS MOVING THRU
ECNTRL SD ATTM...CAUSING A FEW SHOWERS IN NE SD MOVING INTO
WCNTRL/SW MN JUST SOUTH OF THE FCST AREA. ALL MODELS INDICATE
THESE SHOWERS TO CONTINUE GENERALLY SOUTH OF OUR FCST AREA THRU
MID MORNING IN A WEAK 850 MB WARM ZONE.
MEANWHILE...NO TSTMS OUT IN WRN ND/ERN MT AT 08Z...SO STAGE IS SET
FOR A GENERALLY DRY DAY UNTIL A SIGNIFICANT SHORT WAVE MOVES FROM
SOUTHERN ALBERTA INTO NRN ND BY 00Z. THIS SHORT WAVE WILL SWING
THRU ERN ND TONIGHT INTO NRN MN AFTER 06Z.
QUESTION IS TSTM COVERAGE AND INTENSITY WITH SYSTEM. DID LIKE THE
SPC 4 KM WRF AND THE NSSL WRF AS THEY BOTH SHOWED REASONABLE
SCNERIOS IN THEIR REFLECTIVITY/PRECIP PATTERNS. STORMS IN ALBERTA
WILL MOVE INTO SRN SASK AND NW ND MIDDAY AND THEN LOOK FOR
INTENSIFICATION AS STORMS MOVE INTO SE SASK/SW MANITOBA AND CNTRL
ND MID TO LATE AFTN...WITH AREA OF STORMS MOVING THRU ERN ND 00Z-
03Z REACHING NW MN 03Z-06Z PERIOD. LOOKING AT VARIOUS SEVERE
WEATHER FIELDS IT WOULD INDICATE BEST CHC OF SFC BASED SEVERE
CONVECTION IN THE MOT-DVL REGION 22Z-00Z PERIOD...THEN MOVING EAST
AND INCREASINGLY INSTABILITY BECOMING MORE ELEVATED IN NATURE AND
AREA GROWING IN SIZE AS IT MOVE INTO THE NRN/CNTRL RRV TONIGHT. 40
KT LOW LEVEL JET PREDICTED WITH BEST COVERGENCE IN SRN MANITOBA
AND THUS MOST WIDESPREAD RAINS LIKELY ALONG OR NORTH OF THE
BORDER...BUT MODELS DO TAKE SFC LOW THRU NRN ND SO MORE DISCRETE
CELLS PSBL WITH THIS. SRN FCST AREA WHILE NOT CAPPED PER SE HAS A
BIT MORE CIN AND LESS COVERAGE OF STORMS.
ANY STORMS WILL EXIT MN FCST AREA BY 15Z MON AS HIGH PRESSURE
BUILDS IN WITH SOME CLEARING.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 329 AM CDT SUN JUL 21 2013
HIGH PRESSURE WILL GIVE DRY CONDITIONS MON NIGHT INTO
TUESDAY...WITH NEXT SHORT WAVE DUE TO ARRIVE LATER TUES NIGHT. GEM
APPEARS OVERDONE WITH PRECIP THOUGH.
WDNESDAY THROUGH SATURDAY NIGHT...00 UTC GFS/ECMWF BOTH SHOW
NORTHWEST FLOW ALOFT...AMPLIFYING BY LATE IN THE WEEK WITH A
BUILDING RIDGE ACROSS THE INTERMOUNTAIN WEST AND A LOBE OF THE POLAR
VORTEX DIGGING INTO ONTARIO. THIS LATTER FEATURE WILL BE THE PRIMARY
FOCUS FOR ANY PRECIPITATION...BUT MODELS DIFFER ON THE TIMING AND
LOCATION OF INDIVIDUAL BITS OF ENERGY. THE GFS IS MOST BULLISH WITH
PRECIPITATION WEDNESDAY NIGHT THROUGH THURSDAY...WHEREAS THE ECMWF
PAINTS THE MOST QPF ACROSS THE REGION FRIDAY NIGHT INTO SATURDAY.
POP FORECAST CONFIDENCE IS LOW...SO WILL STICK WITH ALL BLEND 20 TO
30 POPS FOR MUCH OF THE PERIOD. AT THIS TIME...FRIDAY LOOKS TO BE
THE DRIEST DAY. FORECAST AREA SHOULD REMAIN ON THE COOL SIDE OF
THE MID-LEVEL THERMAL GRADIENT...SO EXPECT TEMPERATURES SLIGHTLY
BELOW SEASONAL NORMALS WITH HIGHS IN THE 70S AND LOWS IN THE 50S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 735 AM CDT SUN JUL 21 2013
MAIN ISSUE AVIATION WISE WILL BE TIMING ANY THUNDERSTORM THREATS.
GOT SOME VFR STRATOCU ADVANCING NORTHEAST THRU BJI-PKD REGION WITH
SCATTERED VFR STRAOCU ELSEWHERE. HIGH CLOUDS SPREADING SOUTHEAST
FROM CANADA WILL OVERSPREAD THE AREA THIS MORNING-MIDDAY. LATEST
MODEL GUIDANCE INDICATES LOW TO MOVE TOWARD MINOT AROUND 23Z THEN
EASTWARD FROM THERE WITH CHC OF TSTMS IN DVL 23Z-03Z...GFK 02-06Z
AND THEN AFTER 06Z IN BEMIDJI. THREAT FOR STORMS IN FARGO LOWER
AND THUS NOT INCLUDED IN TEMPO GROUP YET. WINDS WILL TURN SOUTH-
SOUTHEAST AT 15 KTS IN DVL WITH 5-15 KTS ELSEWHERE.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...RIDDLE
SHORT TERM...RIDDLE
LONG TERM...RIDDLE/ROGERS
AVIATION...RIDDLE
AREA FORECAST DISCUSSION...UPDATED
NWS MEMPHIS TN
646 AM CDT SUN JUL 21 2013
.UPDATE...
UPDATED FOR AVIATION.
&&
.PREV DISCUSSION... /ISSUED 424 AM CDT SUN JUL 21 2013/
DISCUSSION...
A WET WEATHER PATTERN WAS BEGINNING TO TAKE SHAPE ACROSS THE
MIDSOUTH THAT WILL LEAD TO SEVERAL DAYS WITH SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS. BY THURSDAY...MANY LOCATIONS ARE EXPECTED
TO HAVE RECEIVED TWO OR THREE OF RAIN...LOCALLY MORE.
EARLY THIS MORNING...A NEARLY STATIONARY FRONT STRETCHED TO THE
NORTH OF THE MIDSOUTH FROM CENTRAL MO TO SOUTHERN IN. OUTFLOW
BOUNDARIES FORMED IN ASSOCIATION WITH THUNDERSTORMS THAT DEVELOPED
SOUTH OF THIS FRONT WITH THESE BOUNDARIES PUSHING INTO EAST AR AND
NORTHWEST TN LAST EVENING. THIS SPARKED SCATTERED THUNDERSTORMS IN
PORTIONS OF THIS REGION DURING THE NIGHT BUT MOST HAVE NOW
DISSIPATED. A FEW SHOWERS AND THUNDERSTORMS DEVELOPED EARLY THIS
MORNING ACROSS PORTIONS OF NORTHEAST MS DUE TO A WEAK BUT LARGE LOW
PRESSURE SYSTEM ALOFT CENTERED ALONG THE NORTHEAST LA / CENTRAL MS
BORDER.
SEVERAL FACTORS WILL LEAD TO SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS ACROSS THE MIDSOUTH TODAY AND TONIGHT.
AN UPPER LEVEL SHORT WAVE WILL PUSH TOWARD THE MIDSOUTH FROM THE
NORTHWEST WITH UPPER LEVEL HEIGHTS CONTINUING TO DECREASE TO
UNSEASONABLY LOW VALUES ACROSS THE MIDSOUTH. THE UPPER LEVEL LOW TO
OUR SOUTH WILL PUSH EAST NORTHEASTWARD TO JUST SOUTH OF NORTHEAST
MS. A MOIST AND UNSTABLE ATMOSPHERE WILL EXIST ACROSS THE MIDSOUTH.
A FEW STRONG THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON AND TONIGHT
WITH WEAK MID LEVEL LAPSE RATES LIMITING THE THREAT FOR SEVERE
THUNDERSTORMS. WINDS GUSTS TO NEAR 50 MPH...SMALL HAIL...AND HEAVY
RAINFALL WITH LOCALIZED FLASH FLOODING MAY OCCUR. PRECIPITABLE
WATER VALUES WILL INCREASE TO BETWEEN 2 AND 2.25 INCHES ALONG AND
WEST OF THE MS RIVER. UPPER LEVEL HEIGHTS WILL CONTINUE TO LOWER
ACROSS THE MIDSOUTH TONIGHT AS THE SHORT WAVE EMBEDDED IN A BROAD
UPPER LEVEL TROUGH MOVES INTO THE MIDSOUTH RESULTING IN NUMEROUS
SHOWERS AND THUNDERSTORMS.
ON MONDAY...AN LARGE UPPER LEVEL TROUGH WILL DEEPEN OVER THE EASTERN
UNITED STATES. MID LEVEL LAPSE RATES WILL DECREASE ACROSS THE
MIDSOUTH LEADING TO INCREASED INSTABILITY. NUMEROUS SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS THE REGION. THIS WILL
PLAY HAVOC WITH HIGH TEMPERATURES SINCE IT IS DIFFICULT TO DETERMINE
HOW HOT IT WILL GET BEFORE THE SHOWERS AND STORMS DEVELOP.
A GOOD CHANCE OF SHOWERS AND THUNDERSTORMS WILL CONTINUE MONDAY
NIGHT AND TUESDAY AS UPPER LEVEL SHORT WAVES EMBEDDED IN NORTHWEST
FLOW ALOFT CONTINUE TO INTERACT WITH A MOIST AND UNSTABLE
ATMOSPHERE.
FOR TUESDAY NIGHT AND WEDNESDAY...THE STORMY WEATHER PATTERN WILL
CONTINUE ALTHOUGH THE MODELS ARE NOT IN SYNC WITH THE DETAILS. THE
GFS PUSHES A COLD FRONT INTO THE REGION FROM THE NORTH QUICKER THAN
THE ECMWF DOES. HOWEVER...THE MODELS DO AGREE THAT A VERY UNSTABLE
AND MOIST ATMOSPHERE WILL BE LOCATED OVER THE MIDSOUTH INTO
WEDNESDAY.
KEPT THURSDAY RAINFREE AS DRIER AIR PUSHES INTO THE REGION FOLLOWING
THE PASSAGE OF A WEAK COLD FRONT. FRIDAY LOOKS RAINFREE ALSO WITH A
MILD START TO THE DAY BEFORE AFTERNOON TEMPERATURES WARM TO AROUND
THE NORMAL VALUES FOR THIS TIME OF THE YEAR.
LOOKING AT MODEL FORECAST CHARTS FOR FRIDAY NIGHT AND SATURDAY...YOU
WOULD NOT THINK IT WAS JULY. THE MODELS ARE IN FAIRLY GOOD AGREEMENT
FOR THAT FAR OUT. ANOTHER BROAD UNSEASONABLY DEEP UPPER LEVEL TROUGH
WILL DIG ALONG THE EASTERN UNITED STATES. THE GFS INDICATES A 1010
MB LOW NEAR THE MO BOOTHEEL 7 AM SATURDAY WITH A COLD FRONT
TRAILING TO THE SOUTHWEST WHILE THE ECMWF IS A LITTLE SLOWER AND
STRONGER INDICATING A 1006 MB LOW OVER SOUTH CENTRAL MO WITH A
TRAILING COLD FRONT TO THE SOUTHWEST. A CHANCE OF SHOWERS AND
THUNDERSTORMS WILL OCCUR AHEAD OF THIS SYSTEM FRIDAY NIGHT AND
SATURDAY. COOLER AND DRY HIGH PRESSURE IS FORECAST TO BEHIND INTO
THE REGION FROM THE NORTH WITH PASSAGE OF THE LOW PRESSURE SYSTEM
AND COLD FRONT.
JCL
&&
.AVIATION...
12Z TAFS
PRIMARY FORECAST CONCERN REMAINS TIMING AND LOCATION OF TSRA
ONSET. TSRA CHANCES WILL INCREASE AT ALL LOCATIONS AFTER 15Z.
PRESENCE OF ISOLATED SHRA/TSRA EARLY THIS MORNING INDICATES SOME
ELEVATED INSTABILITY...BUT THIS ACTIVITY HAS FAILED TO ORGANIZE
FOR ANY APPRECIABLE LENGTH OF TIME.
FOR THE 12Z TAFS...HAVE NARROWED TEMPOS DOWN TO NEAR PEAK HEATING
WITH RESPECT TO TSRA TIMING. OF CONCERN IS UPPER LEVEL LOW OVER
NORTHEAST LA...WHICH COULD HELP INITIATE TSRA BY LATE MORNING. GFS
LAMP GUIDANCE AND HRRR MODELS SHOWED LITTLE EFFECT OF THIS UPPER
LEVEL FEATURE FOR THE MORNING HOURS. BUT WILL SKIES TO START THE
DAY... AMPLE SURFACE HEATING OVER THE ARKLAMISS MAY TOUCH OFF
MID/LATE MORNING TSRA POSSIBLY EXTENDING UP TOWARD MEM.
PWB
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 93 74 91 75 / 50 60 60 50
MKL 90 71 89 72 / 50 60 60 50
JBR 92 72 91 73 / 60 60 60 50
TUP 92 73 90 73 / 50 60 60 50
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
622 AM CDT SUN JUL 21 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 300 AM CDT SUN JUL 21 2013
CURRENTLY AS OF 08Z...
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS LOOKED VERY SIMILAR
TO THIS TIME YESTERDAY...CONSISTING OF NORTHWEST FLOW FROM BRITISH
COLUMBIA INTO THE GREAT LAKES REGION...NUMEROUS SHORTWAVES RIDING
THROUGH THE FLOW...AND TROUGHING OVER SOUTHEAST CANADA. MOST OF THE
SHORTWAVES ARE WEAK EXCEPT FOR A MORE IMPRESSIVE ONE OVER CENTRAL
ALBERTA. THE MAIN SHORTWAVE OF INTEREST IN THE SHORT TERM IS
ORIGINATING OUT OF CONVECTION OVER SOUTHEAST SD AND EASTERN
NEBRASKA. AIRMASS OVER THE FORECAST AREA VARIES GREATLY FROM SOUTH
TO NORTH WITH I-94 BEING A GREAT DIVIDING LINE. TO THE NORTH...DRIER
AIR CHARACTERIZED BY SURFACE DEWPOINTS IN THE 40S AND LOW 50S WAS
PRESENT. FARTHER UP TO THE NORTH...THE 00Z INL SOUNDING REPORTED A
PRECIPITABLE WATER VALUE OF 0.49 INCHES. NOW...SOUTH AND WEST OF
I-94...DEWPOINTS ARE IN THE 60S. THE 00Z SOUNDINGS FROM MPX AND DVN
HAD PRECIPITABLE WATER VALUES AROUND 1.15 INCHES. SEPARATING THESE
TWO AIRMASSES IS A STATIONARY FRONTAL BOUNDARY. ISOLATED
SHOWERS/STORMS HAVE BEEN POPPING UP ALONG/NORTH OF THE BOUNDARY ALL
NIGHT.
SYNOPTIC OVERVIEW...
NORTHWEST FLOW CONTINUES THROUGH THE SHORT TERM PERIOD. THE
CONVECTIVELY INDUCED SHORTWAVE TROUGH APPROACHING SIOUX CITY IA AT
08Z MODELS ARE STRUGGLING WITH GREATLY. MOST MODELS...INCLUDING HI
RESOLUTION RUNS SUCH AS THE HRRR AND HIRES-ARW ARE TOO SLOW.
EXTRAPOLATION HAS THE MCV CROSSING MUCH OF IOWA THIS MORNING.
POTENTIAL THEN EXISTS FOR SOME VERY WEAK RIDGING IN ITS WAKE FOR
THIS AFTERNOON AND TONIGHT...AHEAD OF THE CURRENT ALBERTA SHORTWAVE
WHICH DIGS INTO NORTHERN MN AND WESTERN ONTARIO BY 12Z MONDAY.
TODAY...
DESPITE THIS PERIOD BEING THE BEGINNING OF THE FORECAST...THE
UNCERTAINTY IS QUITE HIGH. MUCH OF THIS UNCERTAINTY STEMS FROM THE
TOO SLOW HANDLING FROM ALL MODELS REGARDING THE MCV APPROACHING
SIOUX CITY IA AS OF 08Z. GENERALLY FOLLOWED AN EXTRAPOLATION
APPROACH COMBINED WITH A SOMEWHAT SPED UP 21.05Z HRRR FORECAST TO
COME UP WITH THE FORECAST TODAY. THE PLAN IS THAT THE MCV SHOULD
TRACK ACROSS DES MOINES AND DAVENPORT THIS MORNING...WITH THE
FORECAST AREA ON THE NORTH SIDE. SHOWERS AND A FEW EMBEDDED
THUNDERSTORMS APPEAR LIKELY...PRIMARILY WEST OF THE MISSISSIPPI
RIVER DURING THE MORNING HOURS. CONCERNED THAT THE DIURNAL EFFECTS
ON LOW LEVEL MOISTURE TRANSPORT MAY CAUSE THE SHOWERS TO WEAKEN SOME
AS WE APPROACH MID-DAY...THUS THE HIGHER CHANCES TO THE WEST. DURING
THE AFTERNOON...IT IS HARD TO SAY WHATS GOING TO OCCUR. WE COULD
EASILY BE IN SUBSIDENCE IN THE WAKE OF THE MCV...PREVENTING MUCH IN
THE WAY OF ADDITIONAL PRECIPITATION. ON THE OTHER HAND...THE
AFTERNOON IS PEAK HEATING AND WITH HIGHER DEWPOINTS TODAY...WE
SHOULD BE ABLE TO BUILD 500-1500 J/KG OF CAPE AS SUGGESTED BY THE
RAP. ANY SHORTWAVE COMING THROUGH THE NORTHWEST FLOW THATS HARD TO
DISCERN AT THIS TIME COULD KICK OFF SHOWERS AND STORMS. ADDITIONALLY
WE SHOULD STILL HAVE THAT STATIONARY FRONTAL BOUNDARY IN THE
FORECAST AREA TO PROVIDE WEAK LOW LEVEL CONVERGENCE. THEREFORE...
HAVE MAINTAINED AT LEAST 40-50 PERCENT CHANCES FOR THE AFTERNOON.
REGARDING TEMPERATURES...ASSUMING SOME SUN TODAY WHICH SHOULD
OCCUR...925MB TEMPS IN THE 18-20C RANGE SUPPORTS HIGHS IN THE 70S TO
NEAR 80.
TONIGHT...
ANY CONVECTION THAT OCCURS THIS AFTERNOON WILL LIKELY HAVE A STRONG
DIURNAL COMPONENT TO IT. THEREFORE...HAVE PRECIPITATION CHANCES
DIMINISHING THROUGH THE EVENING HOURS. HOWEVER...850MB MOISTURE
TRANSPORT DOES INCREASE THROUGH THE NIGHT AHEAD OF THE STRONGER
SHORTWAVE DROPPING INTO NORTHERN MN. CONVECTION WILL LIKELY FORM ON
THE NOSE OF THIS MOISTURE TRANSPORT...WHICH IS FORECAST FROM
NORTHERN MN INTO NORTHERN WI. KEPT SOME 20 PERCENT CHANCES OVERNIGHT
BOTH OVER TAYLOR/CLARK COUNTIES FOR THE NOSE OF THIS MOISTURE
TRANSPORT. ALSO KEPT THE 20 PERCENT CHANCES OVERNIGHT FOR THE
EASTERN HALF OF THE FORECAST AREA...IN THE EVENT ANY DIURNAL
CONVECTION CAN SURVIVE...THOUGH AS THE CHANCE STATES THE CONFIDENCE
IS LOW.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 300 AM CDT SUN JUL 21 2013
SYNOPTIC OVERVIEW...
20.00Z ECMWF/GFS/CANADIAN ALL CONTINUE THE NORTHWEST FLOW PATTERN
THROUGH THE ENTIRE LONG TERM PERIOD. WHAT LOOKED TO BE A POSSIBILITY
OF RIDGING BUILDING TOWARDS THE AREA BRIEFLY THURSDAY INTO FRIDAY IS
NOW COMPLETELY GONE. PART OF THE REASON WE STAY IN NORTHWEST FLOW IS
THE DEVELOPMENT OF AN OMEGA BLOCK OVER WESTERN CANADA BETWEEN
TUESDAY AND WEDNESDAY...WHICH DOES NOT SHOW ANY SIGNS OF BREAKING
DOWN FOR AWHILE. ADDITIONALLY...THERE APPEARS TO BE SOME MODEL
STRUGGLES HANDLING SHORTWAVE TROUGHING COMING DOWN THE EAST SIDE OF
THE OMEGA BLOCK...WHICH PUTS MORE UNCERTAINTY FOR THE FORECAST
THURSDAY AND BEYOND. ONE THING THAT IS STARTING TO BECOME A LITTLE
MORE EVIDENT IS FOR DEEPER TROUGHING OVER THE GREAT LAKES REGION AT
THE END OF NEXT WEEKEND. 500MB STANDARDIZED ANOMALIES FOR 12Z SUNDAY
FROM THE ECMWF/GFS ARE 1.5-2 BELOW NORMAL.
HAZARDS...
THERE COULD BE SOME ISOLATED SEVERE WEATHER LATE MONDAY AFTERNOON
INTO THE EVENING HOURS...ASSOCIATED WITH A COLD FRONT COMING
THROUGH...BUT CONFIDENCE IS LOW AS DESCRIBED BELOW.
MONDAY THROUGH TUESDAY NIGHT...
MUCH OF THE FOCUS HERE IS ON THE MONDAY/MONDAY NIGHT PERIOD.
SHORTWAVE TROUGH OVER NORTHERN MN AND WESTERN ONTARIO AT 12Z MONDAY
MODELS ALL AGREE ON SLIDING IT ACROSS NORTHERN ONTARIO. AS THIS
OCCURS...A COLD FRONT ASSOCIATED WITH IT APPROACHES THE FORECAST
AREA. TIMING ON THIS FRONT VARIES GREATLY. AT 00Z TUESDAY...TIMING
VARIES FROM THE 21.00Z HIRES-ARW HAVING IT WEST OF MINNEAPOLIS TO
THE 21.00Z ECMWF/GFS OVER MINNEAPOLIS AND THE 21.00Z
CANADIAN/NAM/UKMET WHICH ARE OVER LA CROSSE. TRENDS AT LEAST FROM
THE ECMWF/GFS SUGGEST A SLOWER APPROACH MAY BE THE WAY TO GO. THERE
STILL REMAINS UNCERTAINTY ON CONVECTIVE CHANCES WITH THIS
FRONT...
1. A WARM SURGE OF AIR AT 800MB IS STILL INDICATED TO COME OVER THE
FRONT TO PROVIDING POTENTIAL CAPPING
2. THE SHORTWAVE TROUGH SLIDING ACROSS NORTHERN ONTARIO COULD END UP
PUTTING RIDGING OVER THE FRONT FOR THE AFTERNOON AS SUGGESTED BY THE
21.00Z HIRES-ARW.
3. LOW LEVEL CONVERGENCE ON THE FRONT REMAINS IN QUESTION.
4. NOW THE FRONT BEING SLOWER...NOT COMING ACROSS THE FORECAST AREA
AT PEAK HEATING...COULD BE A NEGATIVE FOR PRECIP.
TO ACCOUNT FOR THE SLOWER TREND HAVE LOWERED PRECIPITATION CHANCES
SOME MONDAY AFTERNOON. LEFT THE 40-60 PERCENT CHANCES FOR MONDAY
EVENING AS THAT IS STILL FAIRLY WELL AGREED UPON BY GUIDANCE...THEN
CHANCES DIMINISHING AFTER MIDNIGHT WITH LOSS OF HEATING AND THE
FRONT PROGRESSING THROUGH THE AREA. DRY WEATHER FOLLOWS IN THE WAKE
OF THE FRONT FOR TUESDAY AND TUESDAY NIGHT WHILE HIGH PRESSURE
BUILDS IN AT THE SURFACE. 925MB TEMPS CLIMBING TO 21-24C AHEAD OF
THE FRONT ON MONDAY PLUS SUNSHINE WILL ALLOW HIGHS TO CLIMB INTO THE
80S. MAY EVEN SEE 90 IN A FEW SPOTS IF MORE SUN OCCURS. MONDAY LOOKS
HUMID AS WELL AS NEAR 70 DEGREE DEWPOINTS ADVECT IN AT THE SURFACE.
COOLER HIGHS ON THE WAY FOR TUESDAY AS 925MB TEMPS TUMBLE TO 17-20C.
TUESDAY NIGHT LOWS HAVE POTENTIAL TO GET INTO THE 40S AT THE TYPICAL
COLDER SPOTS...DUE TO LIGHT WINDS AND PRECIPITABLE WATER VALUES
FALLING TO 0.5-0.75 INCHES.
WEDNESDAY THROUGH SATURDAY NIGHT...
20.00Z ECMWF/GFS/CANADIAN ARE SUGGESTING NUMEROUS WEAK SHORTWAVES
DROP SOUTHEAST ACROSS THE FORECAST AREA WEDNESDAY THROUGH THURSDAY
IN THE NORTHWEST FLOW ALOFT. HARD TO SAY IF ANY OF THESE ARE GOING
TO DO ANYTHING PRECIP WISE. 20.00Z CANADIAN AND 19.12Z ECMWF WANT TO
BRING SOME SHOWERS ACROSS WEDNESDAY NIGHT AND THURSDAY...THOUGH THE
20.00Z ECMWF BACKED OFF. WOULD THINK A DRIER SCENARIO IS MORE LIKELY
GIVEN THE DRY AIRMASS COMING IN TUESDAY NIGHT/WEDNESDAY WITH
CANADIAN HIGH PRESSURE IN PLACE. NEVERTHELESS...DID HONOR A 20
PERCENT CHANCE MAINLY ON THURSDAY JUST IN CASE. CHANCES INCREASE A
LITTLE FOR THURSDAY NIGHT AND FRIDAY WHERE IT APPEARS A COLD FRONT
WILL CROSS THE AREA...ASSOCIATED WITH A POTENT UPPER TROUGH DROPPING
OVER MANITOBA AND NORTHERN ONTARIO. SOME OF THIS UPPER TROUGH LOOKS
TO SWING ACROSS THE FORECAST AREA FRIDAY NIGHT AND SATURDAY...THUS
STILL NEED TO CONTINUE AT LEAST 20 PERCENT CHANCES. BEING IN THIS
NORTHWEST FLOW PATTERN COMBINED WITH EVEN DEEPER TROUGHING FORMING
OVER THE WEEKEND SUGGESTS BELOW NORMAL TEMPERATURES. BY 12Z
SUNDAY...BOTH THE 20.00Z ECMWF AND GFS DEPICT 850MB TEMPS FALLING TO
6-9C...CHILLY RELATIVELY SPEAKING FOR THE END OF JULY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 622 AM CDT SUN JUL 21 2013
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL IMPACT THE TAF
SITES FROM LATE THIS MORNING THROUGH THIS AFTERNOON. MVFR STRATUS
HAS DEVELOPED ACROSS PORTIONS OF SOUTHWEST WISCONSIN...NEAR THE
MISSISSIPPI RIVER...AND IS JUST EDGING INTO KLSE. PLAN ON THE
MVFR STRATUS TO LINGER THROUGH 14Z THIS MORNING WITH CLOUD BASES
AROUND 1500 FT. A WARM FRONT SITUATED NEAR THE INTERSTATE 90
CORRIDOR WILL GRADUALLY LIFT NORTH THIS AFTERNOON INTO THIS
EVENING WITH MOIST SOUTHERLY FLOW SETTING UP OVER THE REGION IN
THE WAKE OF THE FRONT. WILL HAVE TO KEEP A CLOSE WATCH ON THE
POTENTIAL FOR SOME IFR/MVFR STRATUS TONIGHT AND AREAS OF BR.
CURRENT THINKING IS THAT THERE WILL BE ENOUGH MIXING TONIGHT TO
INHIBIT THE DEVELOPMENT OF THE LOW STRATUS. THERE SHOULD BE A
BREAK IN THE SHOWER AND THUNDERSTORM ACTIVITY LATE THIS EVENING
INTO EARLY MONDAY MORNING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
935 AM MST SUN JUL 21 2013
.UPDATE...UPDATED AVIATION DISCUSSION...
...POTENTIAL FOR HEAVY RAINFALL TODAY...
.SYNOPSIS...
A LOW PRESSURE SYSTEM IN MEXICO WILL CONTINUE TO SUPPLY MOISTURE TO
THE DESERT SOUTHWEST TODAY. HUMID CONDITIONS WILL RESULT IN
WELL-ABOVE NORMAL RAIN CHANCES AND WELL-BELOW NORMAL TEMPERATURES. A
DRYING TREND WILL BEGIN MONDAY...CONTINUING INTO WEDNESDAY AS
HIGH PRESSURE BUILDS BACK OVER THE REGION. MONSOON MOISTURE MOVING
BACK NORTHWARD INTO THE REGION IS LIKELY TO ONCE AGAIN INCREASE RAIN
CHANCES FOR THE END OF THE WEEK AND INTO THE WEEKEND.
&&
.DISCUSSION...
A VERY MOIST AIRMASS IN PLACE IN COMBINATION WITH BROAD UPPER
DIFLUENCE ALOFT CENTERED OVER WESTERN ARIZONA IS CREATING A WET
MORNING ACROSS MUCH OF SOUTHWEST AZ AND AREAS ELSEWHERE. A
UNSEASONABLY STRONG UPPER LOW CENTERED JUST OFF THE WEST COAST OF
BAJA AND A FLATTENED UPPER RIDGE STRETCHING FROM NORTHERN CA INTO CO
HAS RESULTED IN MODEST DIFLUENCE ALOFT. AN OVERNIGHT MCS THAT
DEVELOPED ACROSS SOUTHERN AZ ON THE NORTHERN PERIPHERY OF THE UPPER
LOW CONTINUES TO TRACK NORTHWESTWARD ACROSS WESTERN MARICOPA AND
YUMA COUNTIES. WITH PWATS OF AROUND 2 INCHES...RAINFALL RATES HAVE
BEEN VERY IMPRESSIVE WITH THE STRONGEST THUNDERSTORMS. THE AUTOMATED
RAIN GAGE AT THE BENDER WASH JUST EAST OF GILA BEND REPORTED 2.24
INCHES OF RAIN IN AROUND 45 MINUTES. OTHER GAGES HAVE REPORTED LESS
THAN AN INCH OF RAINFALL...BUT RADAR ESTIMATES INDICATE SOME RURAL
AREAS OF EASTERN YUMA AND WESTERN MARICOPA COUNTIES HAVE RECEIVED 1
TO 2 INCHES OF RAINFALL SINCE 5 AM THIS MORNING.
HEAVY RAINFALL AND THE FLASH FLOOD POTENTIAL WILL BE THE MAIN AND
NEARLY THE ONLY THREAT TODAY. THE 12Z SOUNDING AT KPHX AND FORECAST
SOUNDINGS SHOW AN EXTREMELY MOIST PROFILE WITH NO SIGNIFICANT DRY
LAYERS ALOFT. CAN/T RULE OUT SOME STRONG WIND GUSTS ASSOCIATED
WITH A WET MICROBURST WITH THE STRONGEST STORMS TODAY...BUT GUSTS
WILL MOST DEFINITELY BE SUB-SEVERE. LATEST HRRR AND LOCAL WRF RUNS
SHOW A MIXED PICTURE FOR STORM ACTIVITY FOR THE REST OF TODAY. THE
MCS SHOULD CONTINUE IT/S TRACK NORTHWESTWARD LATE THIS MORNING INTO
THE EARLY AFTERNOON BEFORE EITHER DISSIPATING OR MOVING OUT OF THE
CWA. ADDITIONAL ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS HAVE
DEVELOPED ALONG AND JUST TO THE EAST OF THE MCS OVER CENTRAL
MARICOPA COUNTY SINCE 8 AM MST. CURRENT SATELLITE IMAGERY AND
OBJECTIVE ANALYSIS SHOWS MORE UNSTABLE AIR WITH MIXED LAYER CAPES OF
AROUND 1000 J/KG OVER SOUTH-CENTRAL AND SOUTHEAST AZ. GIVEN THE
SURFACE DEW POINTS IN THE LOWER 70S ACROSS THIS AREA...SHOULD SEE
REDEVELOPMENT OF STORMS EVEN BEFORE NOON TODAY AND MORE LIKELY
THROUGHOUT THE AFTERNOON HOURS. THESE STORMS WILL LIKELY CONTINUE TO
TRACK WESTWARD INTO PORTIONS OF SOUTHWEST AZ AND SOUTHEAST CA THIS
EVENING AND POSSIBLY DURING THE OVERNIGHT HOURS TONIGHT. THE FLASH
FLOOD THREAT SHOULD BE ISOLATED DUE TO THE FAIRLY WORKED OVER
ATMOSPHERE FROM THE PAST 24 HOURS...SO NO FLASH FLOOD WATCHES ARE
EXPECTED AT THIS TIME.
&&
.PREVIOUS DISCUSSION...
UPPER LOW CONTINUES TO SPIN WESTWARD INTO THE PACIFIC OCEAN JUST OFF
THE BAJA PENINSULA. FURTHER NORTH...THE MID-TROPOSPHERIC ANTICYCLONE
REMAINS POSITIONED ACROSS CA/NV. RESULTING MID-LEVEL EASTERLY FLOW
IS STRONGER THAN NORMAL (STANDARDIZED ANOMALY NEAR 1.0) AND
CONTINUES TO ADVECT DEEP SUB-TROPICAL MOISTURE INTO THE FORECAST
AREA. SURFACE DEWPOINTS ARE CURRENTLY IN THE LOWER 70S ACROSS THE
PHOENIX METRO AREA WHILE THE GPS-IPW REGISTERED AROUND 1.75
INCHES...WELL ABOVE NORMAL. LATEST RAP INDICATES THAT PWATS MAY BE
AS HIGH AS 2.0 TO 2.4 INCHES ACROSS THE SOUTHWEST DESERTS AND
TOWARDS PUERTO PENASCO.
LATEST WV IMAGERY SHOWS TWO MCS...ONE ACROSS THE MOJAVE DESERT AND
THE OTHER ACROSS SOUTHERN AZ...BEARING DOWN ON SW AZ AND SE CA.
STRONG LOW-LEVEL CONVERGENCE IS EXPECTED EARLY THIS MORNING AND POPS
WERE INCREASED IN THESE AREAS. ACROSS SOUTH-CENTRAL AZ...NMM AND
WRF-BASED GUIDANCE CONTINUES TO SUGGEST THAT SHOWERS WILL REDEVELOP
AS EARLY AS THIS MORNING. THIS SEEMS REASONABLE GIVEN THE AMPLE
MOISTURE AND IT WILL ONLY TAKE A MINIMAL AMOUNT OF HEATING FOR
CONVECTION TO INITIATE. MODELS ALSO SUGGEST THAT VORTICITY-FORCED
ASCENT WILL AID IN THE DEVELOPMENT OF STORMS THIS AFTERNOON ACROSS
SE CA. ANY STORMS THAT DEVELOP WILL HAVE THE POTENTIAL TO PRODUCE
HEAVY RAIN AND LOCALIZED FLOODING. THE COPIOUS AMOUNT OF MOISTURE
WILL ALSO RESULT IN CONSIDERABLE CLOUDINESS ACROSS MUCH OF THE
AREA...WHICH WILL KEEP TEMPERATURES WELL BELOW NORMAL. FORECAST HIGH
FOR PHOENIX IS 95 DEGREES. A MAX TEMP THIS LOW HAS NOT OCCURRED
SINCE MAY 27.
A SIGNIFICANT DRYING TREND WILL TAKE PLACE MONDAY AS THE UPPER LOW
LIFTS STEADILY NORTHWARD. SHOWERS AND THUNDERSTORMS ARE STILL
ANTICIPATED...THOUGH COVERAGE WILL BE NOTICEABLY LESS THAN WHAT HAS
OCCURRED THE PAST FEW DAYS. THE UPPER LOW WILL BE PICKED UP BY THE
WESTERLIES TUESDAY AS THE MONSOON HIGH BECOMES REPOSITIONED ACROSS
THE ROCKIES. GFS/ECMWF DIFFER ON THE AMOUNT OF MOISTURE LEFT OVER
ACROSS THE DESERT SOUTHWEST THOUGH THE CONSENSUS IS THAT IT SHOULD
BE SUFFICIENT FOR ISOLATED THUNDERSTORMS THROUGH THE WEEK. FLOW WILL
BE WEAK AS AN ANTICYCLONE BUILDS BACK ACROSS AZ AND CONVECTION WILL
MAINLY BE RELEGATED TO THE HIGHER TERRAIN. A WARMING TREND IS ALSO
EXPECTED WITH A RETURN TO ABOVE NORMAL TEMPERATURES BY THURSDAY.
MODELS ARE IN GENERALLY GOOD AGREEMENT THAT ANOTHER PVD WILL SLIDE
WESTWARD THROUGH SONORA LATE IN THE WEEK...RESULTING IN AN INFLUX OF
MOISTURE. FORECAST IS FOR BELOW CLIMO POPS THROUGH
MIDWEEK...FOLLOWED BY NEAR CLIMO POPS THURSDAY THROUGH SUNDAY.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL...
THUNDERSTORMS ARE NOW DEVELOPING...AND MOVING NORTHWARD ACROSS THE
GREATER PHOENIX AREA. THESE STORMS ARE EXPECTED TO AFFECT THE
TERMINALS OVER THE NEXT COUPLE OF HOURS BEFORE SOMEWHAT DRIER AIR
MOVING IN FROM THE SOUTH REDUCES ACTIVITY THIS AFTERNOON AND
EVENING. GENERALLY LIGHT WINDS AND SCT-BKN CLOUD DECKS AOA 6-8KFT
ARE EXPECTED WITH PERIODS OF CIGS LOWERING TO 3-4KFT/VISIBILITIES
REDUCED DOWN TO 4SM IN HEAVIER SHOWERS AND THUNDERSTORMS.
SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH...
ISOLATED SHOWER/THUNDERSTORM ACTIVITY WILL CONTINUE TO FILL IN OVER
SOUTHEAST CALIFORNIA THIS MORNING THROUGH AT LEAST 17Z...WITH GUSTY
OUTFLOWS TO 30KT POSSIBLE AT TIMES...ESPECIALLY NEAR KNYL. SCT-BKN
CLOUD DECKS WITH CIGS DOWN TO AROUND 6-8KFT IN HEAVIER SHOWERS AND
THUNDERSTORMS WITH SKIES/CIGS IMPROVING LATER THIS AFTERNOON. WINDS
S-SELY AROUND 10-15KT THROUGH MUCH OF THE TAF PERIOD ACROSS THE
LOWER COLORADO RIVER VALLEY/KBLH WITH LIGHTER SELY WINDS AT KIPL.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
A SWITCH TO A SOUTHERLY FLOW ALOFT WILL BRING DRYING CONDITIONS AND
ENDING PRECIPITATION CHANCES ACROSS SOUTHEAST CALIFORNIA AND
SOUTHWEST ARIZONA. SLIGHT CHANCES FOR STORMS WILL CONTINUE ACROSS
SOUTH-CENTRAL ARIZONA WITH BETTER CHANCES ACROSS HIGHER TERRAIN
LOCATIONS NORTH AND EAST OF PHOENIX. HUMIDITIES WILL REMAIN ELEVATED
THROUGH THE ENTIRE PERIOD WITH AFTERNOON HUMIDITIES ONLY DROPPING
INTO THE 20-30 PERCENT RANGE WITH GOOD OVERNIGHT RECOVERY.
$$
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...KUHLMAN
PREVIOUS DISCUSSION...HIRSCH
AVIATION...PERCHA/MEYERS
FIRE WEATHER...KUHLMAN
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
923 AM MST SUN JUL 21 2013
...POTENTIAL FOR HEAVY RAINFALL TODAY...
.SYNOPSIS...
A LOW PRESSURE SYSTEM IN MEXICO WILL CONTINUE TO SUPPLY MOISTURE TO
THE DESERT SOUTHWEST TODAY. HUMID CONDITIONS WILL RESULT IN
WELL-ABOVE NORMAL RAIN CHANCES AND WELL-BELOW NORMAL TEMPERATURES. A
DRYING TREND WILL BEGIN MONDAY...CONTINUING INTO WEDNESDAY AS
HIGH PRESSURE BUILDS BACK OVER THE REGION. MONSOON MOISTURE MOVING
BACK NORTHWARD INTO THE REGION IS LIKELY TO ONCE AGAIN INCREASE RAIN
CHANCES FOR THE END OF THE WEEK AND INTO THE WEEKEND.
&&
.DISCUSSION...
A VERY MOIST AIRMASS IN PLACE IN COMBINATION WITH BROAD UPPER
DIFLUENCE ALOFT CENTERED OVER WESTERN ARIZONA IS CREATING A WET
MORNING ACROSS MUCH OF SOUTHWEST AZ AND AREAS ELSEWHERE. A
UNSEASONABLY STRONG UPPER LOW CENTERED JUST OFF THE WEST COAST OF
BAJA AND A FLATTENED UPPER RIDGE STRETCHING FROM NORTHERN CA INTO CO
HAS RESULTED IN MODEST DIFLUENCE ALOFT. AN OVERNIGHT MCS THAT
DEVELOPED ACROSS SOUTHERN AZ ON THE NORTHERN PERIPHERY OF THE UPPER
LOW CONTINUES TO TRACK NORTHWESTWARD ACROSS WESTERN MARICOPA AND
YUMA COUNTIES. WITH PWATS OF AROUND 2 INCHES...RAINFALL RATES HAVE
BEEN VERY IMPRESSIVE WITH THE STRONGEST THUNDERSTORMS. THE AUTOMATED
RAIN GAGE AT THE BENDER WASH JUST EAST OF GILA BEND REPORTED 2.24
INCHES OF RAIN IN AROUND 45 MINUTES. OTHER GAGES HAVE REPORTED LESS
THAN AN INCH OF RAINFALL...BUT RADAR ESTIMATES INDICATE SOME RURAL
AREAS OF EASTERN YUMA AND WESTERN MARICOPA COUNTIES HAVE RECEIVED 1
TO 2 INCHES OF RAINFALL SINCE 5 AM THIS MORNING.
HEAVY RAINFALL AND THE FLASH FLOOD POTENTIAL WILL BE THE MAIN AND
NEARLY THE ONLY THREAT TODAY. THE 12Z SOUNDING AT KPHX AND FORECAST
SOUNDINGS SHOW AN EXTREMELY MOIST PROFILE WITH NO SIGNIFICANT DRY
LAYERS ALOFT. CAN/T RULE OUT SOME STRONG WIND GUSTS ASSOCIATED
WITH A WET MICROBURST WITH THE STRONGEST STORMS TODAY...BUT GUSTS
WILL MOST DEFINITELY BE SUB-SEVERE. LATEST HRRR AND LOCAL WRF RUNS
SHOW A MIXED PICTURE FOR STORM ACTIVITY FOR THE REST OF TODAY. THE
MCS SHOULD CONTINUE IT/S TRACK NORTHWESTWARD LATE THIS MORNING INTO
THE EARLY AFTERNOON BEFORE EITHER DISSIPATING OR MOVING OUT OF THE
CWA. ADDITIONAL ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS HAVE
DEVELOPED ALONG AND JUST TO THE EAST OF THE MCS OVER CENTRAL
MARICOPA COUNTY SINCE 8 AM MST. CURRENT SATELLITE IMAGERY AND
OBJECTIVE ANALYSIS SHOWS MORE UNSTABLE AIR WITH MIXED LAYER CAPES OF
AROUND 1000 J/KG OVER SOUTH-CENTRAL AND SOUTHEAST AZ. GIVEN THE
SURFACE DEW POINTS IN THE LOWER 70S ACROSS THIS AREA...SHOULD SEE
REDEVELOPMENT OF STORMS EVEN BEFORE NOON TODAY AND MORE LIKELY
THROUGHOUT THE AFTERNOON HOURS. THESE STORMS WILL LIKELY CONTINUE TO
TRACK WESTWARD INTO PORTIONS OF SOUTHWEST AZ AND SOUTHEAST CA THIS
EVENING AND POSSIBLY DURING THE OVERNIGHT HOURS TONIGHT. THE FLASH
FLOOD THREAT SHOULD BE ISOLATED DUE TO THE FAIRLY WORKED OVER
ATMOSPHERE FROM THE PAST 24 HOURS...SO NO FLASH FLOOD WATCHES ARE
EXPECTED AT THIS TIME.
&&
.PREVIOUS DISCUSSION...
UPPER LOW CONTINUES TO SPIN WESTWARD INTO THE PACIFIC OCEAN JUST OFF
THE BAJA PENINSULA. FURTHER NORTH...THE MID-TROPOSPHERIC ANTICYCLONE
REMAINS POSITIONED ACROSS CA/NV. RESULTING MID-LEVEL EASTERLY FLOW
IS STRONGER THAN NORMAL (STANDARDIZED ANOMALY NEAR 1.0) AND
CONTINUES TO ADVECT DEEP SUB-TROPICAL MOISTURE INTO THE FORECAST
AREA. SURFACE DEWPOINTS ARE CURRENTLY IN THE LOWER 70S ACROSS THE
PHOENIX METRO AREA WHILE THE GPS-IPW REGISTERED AROUND 1.75
INCHES...WELL ABOVE NORMAL. LATEST RAP INDICATES THAT PWATS MAY BE
AS HIGH AS 2.0 TO 2.4 INCHES ACROSS THE SOUTHWEST DESERTS AND
TOWARDS PUERTO PENASCO.
LATEST WV IMAGERY SHOWS TWO MCS...ONE ACROSS THE MOJAVE DESERT AND
THE OTHER ACROSS SOUTHERN AZ...BEARING DOWN ON SW AZ AND SE CA.
STRONG LOW-LEVEL CONVERGENCE IS EXPECTED EARLY THIS MORNING AND POPS
WERE INCREASED IN THESE AREAS. ACROSS SOUTH-CENTRAL AZ...NMM AND
WRF-BASED GUIDANCE CONTINUES TO SUGGEST THAT SHOWERS WILL REDEVELOP
AS EARLY AS THIS MORNING. THIS SEEMS REASONABLE GIVEN THE AMPLE
MOISTURE AND IT WILL ONLY TAKE A MINIMAL AMOUNT OF HEATING FOR
CONVECTION TO INITIATE. MODELS ALSO SUGGEST THAT VORTICITY-FORCED
ASCENT WILL AID IN THE DEVELOPMENT OF STORMS THIS AFTERNOON ACROSS
SE CA. ANY STORMS THAT DEVELOP WILL HAVE THE POTENTIAL TO PRODUCE
HEAVY RAIN AND LOCALIZED FLOODING. THE COPIOUS AMOUNT OF MOISTURE
WILL ALSO RESULT IN CONSIDERABLE CLOUDINESS ACROSS MUCH OF THE
AREA...WHICH WILL KEEP TEMPERATURES WELL BELOW NORMAL. FORECAST HIGH
FOR PHOENIX IS 95 DEGREES. A MAX TEMP THIS LOW HAS NOT OCCURRED
SINCE MAY 27.
A SIGNIFICANT DRYING TREND WILL TAKE PLACE MONDAY AS THE UPPER LOW
LIFTS STEADILY NORTHWARD. SHOWERS AND THUNDERSTORMS ARE STILL
ANTICIPATED...THOUGH COVERAGE WILL BE NOTICEABLY LESS THAN WHAT HAS
OCCURRED THE PAST FEW DAYS. THE UPPER LOW WILL BE PICKED UP BY THE
WESTERLIES TUESDAY AS THE MONSOON HIGH BECOMES REPOSITIONED ACROSS
THE ROCKIES. GFS/ECMWF DIFFER ON THE AMOUNT OF MOISTURE LEFT OVER
ACROSS THE DESERT SOUTHWEST THOUGH THE CONSENSUS IS THAT IT SHOULD
BE SUFFICIENT FOR ISOLATED THUNDERSTORMS THROUGH THE WEEK. FLOW WILL
BE WEAK AS AN ANTICYCLONE BUILDS BACK ACROSS AZ AND CONVECTION WILL
MAINLY BE RELEGATED TO THE HIGHER TERRAIN. A WARMING TREND IS ALSO
EXPECTED WITH A RETURN TO ABOVE NORMAL TEMPERATURES BY THURSDAY.
MODELS ARE IN GENERALLY GOOD AGREEMENT THAT ANOTHER PVD WILL SLIDE
WESTWARD THROUGH SONORA LATE IN THE WEEK...RESULTING IN AN INFLUX OF
MOISTURE. FORECAST IS FOR BELOW CLIMO POPS THROUGH
MIDWEEK...FOLLOWED BY NEAR CLIMO POPS THURSDAY THROUGH SUNDAY.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL...
NEW STORMS WILL CONTINUE TO DEVELOP TO THE SOUTH AND WEST OF THE
PHOENIX AREA...WITH ACTIVITY SLOWLY BUILDING AROUND AND ENCROACHING
ON THE TERMINALS LATER THIS MORNING AFTER 15Z...PERSISTING INTO THE
AFTERNOON/EARLY EVENING. GENERALLY LIGHT WINDS AND SCT-BKN CLOUD
DECKS AOA 6-8KFT ARE EXPECTED WITH PERIODS OF CIGS LOWERING TO
3-4KFT/VISIBILITIES REDUCED DOWN TO 4SM IN HEAVIER SHOWERS AND
THUNDERSTORMS. STORMS DIMINISH AND SKIES EXPECTED TO IMPROVE AFTER
02Z MONDAY WITH SCT-BKN CLOUD DECKS SETTLING IN AOA 10KFT.
SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH...
ISOLATED SHOWER/THUNDERSTORM ACTIVITY WILL CONTINUE TO FILL IN OVER
SOUTHEAST CALIFORNIA THIS MORNING THROUGH AT LEAST 17Z...WITH GUSTY
OUTFLOWS TO 30KT POSSIBLE AT TIMES...ESPECIALLY NEAR KNYL. SCT-BKN
CLOUD DECKS WITH CIGS DOWN TO AROUND 6-8KFT IN HEAVIER SHOWERS AND
THUNDERSTORMS WITH SKIES/CIGS IMPROVING LATER THIS AFTERNOON. WINDS
S-SELY AROUND 10-15KT THROUGH MUCH OF THE TAF PERIOD ACROSS THE
LOWER COLORADO RIVER VALLEY/KBLH WITH LIGHTER SELY WINDS AT KIPL.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
A SWITCH TO A SOUTHERLY FLOW ALOFT WILL BRING DRYING CONDITIONS AND
ENDING PRECIPITATION CHANCES ACROSS SOUTHEAST CALIFORNIA AND
SOUTHWEST ARIZONA. SLIGHT CHANCES FOR STORMS WILL CONTINUE ACROSS
SOUTH-CENTRAL ARIZONA WITH BETTER CHANCES ACROSS HIGHER TERRAIN
LOCATIONS NORTH AND EAST OF PHOENIX. HUMIDITIES WILL REMAIN ELEVATED
THROUGH THE ENTIRE PERIOD WITH AFTERNOON HUMIDITIES ONLY DROPPING
INTO THE 20-30 PERCENT RANGE WITH GOOD OVERNIGHT RECOVERY.
$$
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...KUHLMAN
PREVIOUS DISCUSSION...HIRSCH
AVIATION...MEYERS
FIRE WEATHER...KUHLMAN
AREA FORECAST DISCUSSION
NWS PUEBLO CO
305 PM MDT SUN JUL 21 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 304 PM MDT SUN JUL 21 2013
DRIER AIR MASS HAS SPREAD OVER THE NORTHERN AND WESTERN PORTIONS OF
THE AREA THIS AFTERNOON...DROPPING DEW POINTS INTO THE 20S OVER THE
CENTRAL MOUNTAINS AND ACROSS TELLER COUNTY. LOW LEVEL MOISTURE STILL
LURKS ON THE PLAINS...WHERE DEWPOINTS IN THE 50S HAVE LED TO CAPES
IN EXCESS OF 2K J/KG EAST OF I-25. VERY LITTLE IN THE WAY OF
FORCING/UPWARD MOTION THIS AFTERNOON...WITH ONLY VERY SPARSE
MOUNTAIN CONVECTION MAINLY SOUTH OF HIGHWAY 50. HAVE ALSO SEEN A
COUPLE CELLS DEVELOP THEN DISSIPATE QUICKLY OVER EASTERN EL PASO
COUNTY...WHERE MOISTURE GRADIENT IS FAIRLY TIGHT AND RESIDUAL
BOUNDARY FROM LAST NIGHT`S CONVECTION REMAINS. LATEST HRRR HINTS AT
TSRA DEVELOPING EAST OF I-25 THIS EVENING....AND WHILE FORCING IS
WEAK...LARGE CAPES ARE HARD TO IGNORE...AND WILL THROW IN SOME LOW
POPS FOR THE PLAINS EARLY THIS EVENING. STILL EXPECT ANY STORMS TO
DISSIPATE QUICKLY AFTER SUNSET. ON MONDAY...AIR MASS CONTINUES TO
DRY...AND EVEN THE MOUNTAINS WILL BE HARD PRESSED TO SEE MORE THAN
SOME MODERATE CUMULUS BUILD-UP IN THE AFTERNOON. KEPT SOME VERY LOW
POPS IN PLACE OVER THE HIGHER PEAKS...BUT EVEN THESE MAY BE
OVERDONE. RISING HEIGHTS AND MID-LEVEL TEMPS SUGGEST A HOT DAY IS IN
STORE...AS READINGS ON THE PLAINS REACH 100F...WITH 80/90S
ELSEWHERE.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 304 PM MDT SUN JUL 21 2013
THE ENTIRE EXTENDED FORECAST PERIOD CAN BE SUMMED UP IN TWO
SENTENCES. AN UPPER RIDGE OF HIGH PRESSURE WILL REMAIN LOCKED INTO
PLACE ACROSS THE REGION. MINOR DISTURBANCES IN THE FLOW ALOFT
ROTATING AROUND THE RIDGE WILL KICK OFF ENHANCED CONVECTION TOWARDS
THE LATTER HALF OF THE WEEK. NOW FOR THE SPECIFICS...
MONDAY NIGHT THROUGH TUESDAY...EC...GFS AND EVEN THE NAM MODEL ARE
NOW INDICATING THAT IT SHOULD REMAIN FAIRLY DRY THROUGH MUCH OF
TUE...WITH ISOLATED TO LOW END SCATTERED POPS OVER THE HIGHER
TERRAIN. A COLD FRONT DROPS DOWN TO THE PALMER DVD ON TUE...BUT THE
LATEST RUNS INDICATE IT DOES NOT DROP SOUTH UNTIL LATE TUE...SETTING
THE STAGE FOR WED. LOOK FOR MAX TEMPS ACROSS THE E PLAINS TO BE
AROUND 100 DEG F ON TUE...AND IN THE MID TO UPPER 80S FOR THE HIGH
VALLEYS.
WEDNESDAY THROUGH FRIDAY...THE COLD FRONT WILL DROP SOUTH ACROSS THE
CWA LATE TUE...WITH WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY
EXPECTED FOR A MAJORITY OF THE FORECAST AREA BOTH WED AND THU. MAX
TEMPS ARE EXPECTED TO BE ABOUT 10 DEGREES COOLER WITH SCATTERED POPS
ALL AREAS BORDERING ON LIKELY. WED AFTN THROUGH THU AFTN LOOKS LIKE
IT WILL BE THE MOST PROBABLY TIME FRAME FOR FLASH FLOOD POTENTIAL
ACROSS AREA BURN SCARS. BY FRIDAY THE UPPER RIDGE AXIS STARTS TO
SHIFT SLIGHTLY TO THE EAST AS THE RIDGE AMPLIFIES...AND THOUGH THERE
IS STILL A GOOD CHANCE FOR CONVECTION FOR ALL AREAS...IT WILL BE DUE
TO A REINFORCED MONSOON PLUME AS OPPOSED TO FRONTAL/LLVL FORCING.
TEMPS ON FRI WILL BE AS COOL OR PERHAPS EVEN A COUPLE OF DEGREES
COOLER.
SATURDAY AND SUNDAY...EXTENDED MODELS ARE POINTING TO ANOTHER
STRONGER DISTURBANCE MOVING ACROSS THE DAKOTAS AND MIDWEST ON
SAT...PUSHING ANOTHER COOLD SURGE INTO EASTERN CO LATE SAT INTO SUN.
WHEREAS SAT IS FORECAST TO HAVE DIURNAL CONVECTIVE ACTIVITY TIED
MAINLY TO THE HIGHER TERRAIN...SUNDAY COULD BE ANOTHER ACTIVE DAY
WITH WIDESPREAD CONVECTION AND SLIGHTLY COOLER TEMPS. MOORE
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 304 PM MDT SUN JUL 21 2013
ISOLATED TSRA HAVE BEEN DEVELOPING JUST EAST OF KCOS ALONG A WEAK
BOUNDARY...AND WHILE CURRENT STORM MOTION SUGGESTS ACTIVITY WILL
STAY EAST OF THE TERMINAL...GUSTY AND ERRATIC OUTFLOW WINDS MAY
DEVELOP FOR A FEW HOURS AFTER 21Z. MAY ALSO SEE TSRA GET CLOSE
ENOUGH TO PRODUCE SOME GUSTY WINDS AT KPUB...ESPECIALLY AFTER 22Z.
AT KALS...MAY SEE SOME TSRA OVER THE SAN JUANS DRIFT INTO THE AREA
AFTER 22Z...THOUGH AGAIN STORMS MAY DISSIPATE BEFORE THEY REACH THE
TERMINAL. CONVECTION WILL DIMINISH AFTER SUNSET...AND VFR CONDITIONS
EXPECTED ALL TAF SITES AFTER 03Z THIS EVENING. ON MONDAY...TAF SITES
WILL STAY VFR WITH ONLY VERY SPARSE HIGH BASED CONVECTION EXPECTED
OVER THE MOUNTAINS.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...PETERSEN
LONG TERM...MOORE
AVIATION...PETERSEN
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
257 PM MDT SUN JUL 21 2013
.SHORT TERM...STRONG OUTFLOW FROM T-STORMS UP IN NEBRASKA LAST
NIGHT...BACKED ACROSS NORTHEAST COLORADO EARLIER TODAY. THIS
SHALLOW MOIST AIRMASS SIGNIFICANTLY INFLUENCED TEMPERATURES EAST
OF THE MOUNTAINS TODAY. CURRENT TEMPERATURES ARE RUNNING SEVERAL
DEGS BEHIND THOSE YESTERDAY AT THIS TIME...THEREBY CREATING A
STRONG CAP UP AROUND 750 MBS NEAR THE FOOTHILLS...AND UP AROUND
700 MBS FARTHER OUT OVER THE PLAINS ACCORDING RUC SOUNDINGS AND
CROSS SECTIONS. BENEATH THIS PSUEDO-FRONTAL INVERSION...BNDRY
LAYER CAPE VALUES ARE NOW NEAR 700 J/KG UP AGAINST THE FOOTHILLS
AND CLOSE TO 1500 J/KG IN THE FAR NORTHEAST. DO SEE THIS ENERGY
BEING TAPPED NEAR THE FOOTHILLS EVEN WITH ISOLATED LOW TOP
CONVECTION DRIFTING OFF THE FOOTHILLS WITH ALL OF THE CIN IN THIS
AREA. FARTHER OUT ON THE PLAINS...COULD SEE THE WEAK SHORTWAVE
DISTURBANCE NOW SWINGING OVER SERN WYOMING TAPPING INTO SOME OF
THIS PENNED UP ENERGY RESULTING IN A FEW T-STORMS IN THE FAR
NORTHEAST COUNTIES AFTER 5 PM MDT TODAY. MORE LIKELY WE/LL SEE
THIS CONVECTION DURING THE EVENING HOURS WITH THE LAST OF THE
CIN ERRODING AS THE SHORTWAVE PASSES BY. NOT LOOKING FOR ANY
SEVERE WX OUT OF THEM...JUST PERHAPS SOME SMALL HAIL...BRIEF HEAVY
RAIN AND GUSTY OUTFLOW WINDS TO AROUND 50 MPH. STORMS SHOULD END
EARLIER TONIGHT WITH ARRIVAL OF DRIER AND MORE STABLE AIR BEHIND
THIS SHORTWAVE. HOWEVER...LINGERING LOW LEVEL MOISTURE MAY AGAIN
RESULT IN AREAS OF LOW CLOUDS AND/OR PATCHY FOG IN THE FAR
NORTHEAST TOWARDS MORNING.
ON MONDAY...AIRMASS APPEARS MUCH DRIER AND WARMER. WITH THE UPPER
RIDGE STRENGTHENING TO OUR WEST..AND BARRING ANY UNFORESEEN MOIST
OUTFLOW FROM DOWNSTREAM STORMS...SHOULD SEE TEMPERATURES EASILY
CLIMBING INTO THE 90S ON THE PLAINS TOMORROW...WITH 70S AND 80S IN
THE MTNS. IT/S NOT OUT THE QUESTION WE COULD SEE LOW 90S POPPING
UP IN A FEW SPOTS ALONG THE UPPER COLORADO IN GRAND COUNTY.
DO NOT ANTICIPATE ANY PRECIPITATION/T-STORMS ON MONDAY.
.LONG TERM...OVERALL NO BIG CHANGES TO THE ONGOING TRENDS IN THE
FORECAST. THE UPPER LEVEL RIDGE WILL BE CENTERED NEAR THE GREAT
BASIN FOR MONDAY NIGHT INTO TUESDAY. AS A RESULT...A DRY AND
STABLE NORTHWESTERLY FLOW ALOFT WILL BE OVER THE CWFA. PLENTY OF
LOW LEVEL MOISTURE OVER THE NORTHEAST PLAINS...BUT TOO SUBSIDENT
IN THE MID LEVELS TO ALLOW THE INITIATION OF DEEP CONVECTION FOR
MOST OF THE FORECAST AREA. A WEAK SYSTEM PASSING ACROSS THE NRN
GREAT PLAINS AND INTO THE MID WEST COULD BE ENOUGH TO INITIATE
TSTMS OVER THE FAR NERN CORNER OF CO LATE TUESDAY. FOR THE REST OF
THE WEEK...THE CENTER OF RIDGE SHIFTS EASTWARD WHICH OPENS UP
WESTERN CO TO SUBTROPICAL MID MOISTURE FM THE SOUTH. BETTER TSTM
COVERAGE SHOULD HELP TO SHAVE A FEW DEGREES OF THE AFTN
TEMPERATURES AS WELL. THE ECMWF AND GFS BOTH SHOW BOTH DEVELOP
DECENT QPF OVER THE AREA LATE WEDNESDAY AND THURSDAY...WITH A BIT
OF DRYING ON FRIDAY. MDLS DIFFER AS TO HOW MUCH MOISTURE WILL BE
AVAILABLE OVER THE WEEKEND SO SLGT CHC SHOULD SUFFICE FOR NOW.
&&
.AVIATION...VFR CONDITIONS ANTICIPATED FOR THE NEXT 24 HOURS
UNDER NORTHWEST FLOW ALOFT. NORTH-NORTHEAST SURFACE WINDS UNDER
12 KTS AT MOST DENVER AREA AIRPORTS SHOULD GRADUALLY BECOME
EASTERLY AT SIMILAR SPEEDS AFTER 23Z AND LINGER THROUGH EARLY
EVENING...THEN GO TO A DRAINAGE WIND OVERNIGHT. DIA AND APA COULD
SEE GUSTY SOUTHERLY WINDS OF 10-20 KTS DEVELOPING IN THE EVENING
WITH THE FORMATION A TIGHT PRES GRADIENT JUST EAST OF THE METRO
AREA. AFTER SAY 08Z...SHOULD SEE WIND SPEEDS RELAX AND RESUME
MORE TYPICAL SPEEDS UNDER 12KS. ON MONDAY SOUTHERLY WINDS UNDER
12KS ARE FORECAST TO GO WEST-NORTHWEST BY LATE MORNING AT SIMILAR
SPEEDS. WITH FEW CLOUDS AROUND...SHOULD SEE DAYTIME TEMPERATURES
RETURNING TO THE 90S.
&&
.HYDROLOGY...NO CONCERNS AT THIS TIME.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BAKER
LONG TERM....COOPER
AVIATION...BAKER
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
316 PM EDT SUN JUL 21 2013
.DISCUSSION...
CURRENTLY-TONIGHT...DEBRIS CLOUDINESS HAS JUST ABOUT EXITED THE
AREA BUT CONVECTION HAS BEEN DELAYED A BIT. EXPECT SCATTERED
SHOWERS/STORMS FORMING ALONG THE WEST COAST BOUNDARY TO MARCH
ACROSS THE PENINSULA AS THE LATEST RAP WAS SHOWING STEERING LEVEL
WINDS NEAR 15 KNOTS. WITH THE LIMITED SOLAR INSOLATION...THE EAST
COAST SEA BREEZE WILL ONLY HAVE LIMITED INLAND MOVEMENT...MAINLY
FROM THE CAPE SOUTHWARD. STILL THIS MAY CAUSE A FEW STRONGER
STORMS THERE THROUGH EARLY EVENING. SOME POCKETS OF INSTABILITY
MAY LINGER THROUGH EVENING SO WILL GO WITH CHANCE POPS IN ALL ZONES.
MON-TUE...MID LEVEL RIDGE WITH AXIS JUST SOUTH OF THE AREA WILL
BREAK DOWN AS A TROUGH BECOMES ESTABLISHED OVER THE EASTERN CONUS.
THE LATEST GFS INDICATES SOME DRIER MID LEVEL AIR BEING ADVECTED
IN FROM THE GULF SO POPS ARE EXPECTED TO DECREASE A LITTLE. HOWEVER
THE WESTERLY STEERING LEVEL FLOW SHOULD FAVOR POPS CLOSE TO CLIMO
(40 PERCENT) EXCEPT 50 PERCENT IN THE NORTH WHERE MOISTURE
CONVERGENCE WILL BE HIGHER (NORTH OF LOW LEVEL RIDGE AXIS).
WITH SURFACE RIDGE AXIS OVER THE SOUTHERN PENINSULA...THE
WESTERLY FLOW SHOULD INCREASE A LITTLE EACH DAY AND BY TUE THE
EAST COAST SEA BREEZE MAY BE INHIBITED ALL BUT THE FAR SOUTH. THIS
SHOULD BOOST MAX TEMPS...THOUGH WILL NOT GO AS HIGH AS THE LATEST
GFS WHICH HAS SOME 93-94 DEGREE HIGHS. THIS WOULD BE ESPECIALLY
TRUE IF SOME UPPER LEVEL DEBRIS CLOUDS PERSIST LIKE THE PAST FEW
DAYS.
PREVIOUS DISCUSSION...
WED-SAT...THE CENTER OF SURFACE HIGH PRESSURE OVER THE WESTERN
ATLANTIC RETREATS SEAWARD AS ITS WESTWARD EMANATING AXIS FULLY
ADJUSTS TO SOUTH FLORIDA AND PERHAPS EVEN AS FAR AS THE STRAITS.
THIS WILL KEEP CENTRAL FLORIDA IN THE LOW-LEVEL WESTERLIES THRU
THE PERIOD. TROUGHING HANGS UP OVER THE ATLANTIC SEABOARD BOTH
SURFACE AND ALOFT TO KEEP WEATHER MORE DISTURBED JUST NORTH OF THE
FORECAST AREA...WITH MINOR WAVES AND VORT MAXES MOVING AROUND THE
BASE OF THE UPPER TROUGH. LOOKS LIKE SOME DRYING WORKS ITS WAY IN
FROM THE GULF FOR SOUTH FLORIDA TO PROMPT POPS GREATER NORTH AND
SOMEWHAT LOWER SOUTH LATER IN THE PERIOD. POPS AROUND 40 PERCENT
NORTH AREA EACH DAY. FOR SOUTH AREA...40 PERCENT DROPPING BACK TO
30-35 PERCENT BY FRI.
&&
.AVIATION...
LATER DEVELOPING CONVECTION DUE TO DEBRIS CLOUDS BUT EXPECT
ACTIVITY ALONG WEST COAST BOUNDARY TO MARCH STEADILY ACROSS THE
PENINSULA...SO CHANCE POPS ARE IN ORDER THROUGH ABOUT 00Z. SOME
STRONG STORMS ARE STILL POSSIBLE ESPECIALLY KMLB-KSUA WHERE
BOUNDARY INTERACTIONS BECOME MORE NUMEROUS.
SURFACE TO MID LEVEL WESTERLY FLOW WILL FAVOR STORMS MARCHING
ACROSS THE PENINSULA FROM WEST TO EAST ON MON AFTERNOON AGAIN.
&&
.MARINE...
TONIGHT-MON...NEAR 15 KNOT SOUTHWEST WINDS EXPECTED CANAVERAL
NORTHWARD THIS EVENING THEN DIMINISHING TO 10 KNOTS OR LESS LATE
AND INTO MON MORNING. THE MAIN MARINER CONCERN WILL BE OFFSHORE
MOVING STORMS THROUGH THIS EVENING AND AGAIN MON AFTERNOON.
TUE-FRI...HIGH PRESSURE RIDGE AXIS WILL EXTEND SOUTH OF THE WATERS
AND RESULT IN SOUTH/SOUTHWEST FLOW THROUGH THE PERIOD. SPEEDS
SHOULD GENERALLY BE 10-15 KNOTS. EXPECT SCATTERED STORMS OVER THE
MAINLAND TO SWEEP OFFSHORE EACH AFTERNOON. THE RIDGE AND STEERING
LEVEL WINDS ARE FORECAST TO WEAKEN BY FRI WHICH MAY KEEP AFTERNOON
STORMS MAINLY OVER THE PENINSULA.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 73 89 75 90 / 30 50 30 50
MCO 74 92 74 91 / 20 40 20 40
MLB 74 89 72 90 / 30 40 20 40
VRB 72 90 73 90 / 20 40 20 40
LEE 75 91 75 91 / 20 40 30 50
SFB 76 92 75 91 / 20 40 30 40
ORL 75 92 76 91 / 20 40 30 40
FPR 73 89 72 90 / 20 40 20 40
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
FORECASTS...RL
IMPACT WEATHER/RADAR...TES
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1252 PM CDT SUN JUL 21 2013
.SYNOPSIS...
ISSUED AT 252 AM CDT SUN JUL 21 2013
A QUIET NIGHT ACROSS THE AREA WHILE THUNDERSTORMS RAIN OVER THE
CENTRAL PLAINS. THE SURFACE AND 850 MB FRONTAL BOUNDARIES RESIDE
TO OUR SOUTH IN NORTHERN MISSOURI AND ARE ASSOCIATED WITH
WEAKENING STORMS. ANOTHER BOUNDARY TO OUR NORTH ACROSS MINNESOTA AND
WISCONSIN IS ASSOCIATED WITH ACTIVE STORMS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 252 AM CDT SUN JUL 21 2013
MAIN CONCERN IN THIS TIME FRAME IS THUNDERSTORM CHANCES TODAY AND
THIS EVENING. MODELS OTHER THAN THE RAP AND HRRR HAVE A WEAK
HANDLE ON THE PLAINS CONVECTION. AND THIS SYSTEM WITH ITS ASSOCIATED
SHORT WAVE TROUGH/MCV WILL BE OUR WEATHER MAKER FOR TODAY.
OVERALL CURRENT CONVECTIVE TRENDS IN THE PLAINS ARE WEAKENING
EXCEPT FOR REDEVELOPING STORMS ON THE TAIL OF THE MCS WHICH IS
REACHING THE MISSOURI RIVER. TIMING OF THE SHORT WAVE INTO OUR
AREA IS SUCH THAT THE ATMOSPHERE SHOULD DESTABILIZE THROUGH THE
MORNING...ALBEIT WITH SUNSHINE FILTERED BY MID AND HIGH CLOUDS.
MODELS SEEM TO WEAKEN THE WAVE...AND THE NAM EVEN TAKES IT SOUTH
OF THE CWA. BUT THE ATMOSPHERE SHOULD BE PRIMED FOR CONVECTION...
AND IF THE SURFACE AND 850MB FRONTS ARE PULLED NORTH WITH THE
TROUGH...WE WILL HAVE A FOCAL POINT FOR STORM INITIATION. SINCE
FLOW IS WEAK AND MODEL FORECASTS ARE DIVERGENT ON THIS ISSUE...
HAVE GENERALLY HELD POPS IN THE HIGH CHANCE RANGE. SLOW MOVING
STORMS COULD PRODUCE LOCALLY HEAVY RAIN...AND THE ENVIRONMENT
SUPPORTS AN ISOLATED RISK OF DOWNBURSTS.
MAX TEMPS TODAY RELATIVE TO YESTERDAY WILL BE HINDERED SOME BY
CLOUD COVER. OVERNIGHT LOWS WILL BE MORE REFLECTIVE OF THE WARM
SECTOR IN MISSOURI AS WINDS SHIFT TO THE SOUTH TONIGHT. WOLF
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 252 AM CDT SUN JUL 21 2013
THE DEEP MOIST AIR MASS AHEAD OF AN EARLY TUE FROPA WILL CONTINUE
THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS MONDAY INTO MONDAY
NIGHT. DEVELOPING NW ALOFT AND HIGH PRESSURE TO THEN PROVIDE DRY
WEATHER AND SLIGHTLY COOLER TEMPERATURES FOR MOST OF THE UPCOMING
WORKWEEK. RAIN CHANCES RETURN LATE WEEK INTO THE WEEKEND WITH
TEMPERATURES POSSIBLY TRENDING WELL BELOW NORMAL BY SUNDAY.
MONDAY...WEAK MID LEVEL SUBSIDENCE AND LACK OF SIGNIFICANT SURFACE
BOUNDARIES WILL BE UNFAVORABLE FOR ANYTHING BEYOND ISOLATED
CONVECTION OVER MOST OF THE AREA AND HAVE LOWERED POPS TO SLIGHT
CHANCES FOR MOST OF THE DAY. THE EXCEPTION IS ACROSS THE FAR
NW...WHERE DEVELOPING LIFT AHEAD OF AN APPROACHING SHORTWAVE AND
SURFACE COLD FRONT MAY LEAD TO THUNDERSTORMS DURING LATE DAY PEAK
HEATING AND HAVE CHANCE POPS. PREFRONTAL WARMING AND WEDGE OF WARM
AIR AT 850 MB WILL SUPPORT HIGHS FROM THE MID 80S NORTH TO AROUND 90
SOUTH. DEW POINTS IN THE UPPER 60S TO LOWER 70S MAY DRIVE HEAT
INDEX READINGS INTO THE UPPER 90S ACROSS THE SOUTH.
MONDAY NIGHT INTO EARLY TUESDAY...THERE IS A SIGNIFICANT SPREAD
AMONG THE MODELS WITH THE TIMING OF THE SURFACE COLD FRONT. THE GFS
HAS TRENDED THE SLOWEST...NOT BRINGING THE FRONT THROUGH UNTIL MID
MORNING...WHILE THE ECMWF HAS THE SURFACE WIND SHIFT WELL BEFORE
SUNRISE. WILL STAY CLOSER TO A FASTER CONSENSUS KEEPING CHANCE POPS
FOCUSED ON THE OVERNIGHT PERIOD...FOLLOWED BY SLIGHT CHANCES OVER
MAINLY THE EAST TUESDAY MORNING. WILL CONTINUE TO HAVE A THREAT FOR
LOCALLY HEAVY RAINFALL DUE TO THE HIGH PW VALUES IN PLACE MONDAY
NIGHT. KEPT MINS FROM THE MID 60S NORTH TO THE LOWER 70S SOUTH.
TUESDAY THROUGH THURSDAY...CANADIAN HIGH PRESSURE BUILDS SOUTH INTO
GREAT LAKES UNDER A NW FLOW ALOFT TO PROVIDE A PERIOD OF SEASONABLY
MILD AND LESS HUMID CONDITIONS. WED LOOKS TO BE THE COOLEST AS THE
POSITIONING OF THE PASSING HIGH WILL PROVIDE A LOW LEVEL NORTHEAST
FETCH AND THE COOLEST TEMPERATURES AT 850 MB. THIS MAY RESULT IN
HIGHS LIMITED TO THE 70S ACROSS THE CENTRAL AND NORTH...WHILE BOTH
TUE AND THU WILL LIKELY SEE WIDESPREAD LOWER TO MID 80S. THIS
SEASONABLY DRY AIR MASS WILL SUPPORT LOWS IN THE 60S WITH SOME
POCKETS OF 50S POSSIBLE THU MORNING.
GULF MOISTURE RETURNS TO THE REGION THU NIGHT INTO FRIDAY. THIS AND
A COLD FRONT SHOWN PUSHING THROUGH FRIDAY NIGHT OR SATURDAY WILL
BRING THUNDERSTORM CHANCES BACK TO THE AREA. THE LATEST GFS AND
ECMWF THEN DEVELOP A SIGNIFICANT UPPER TROUGH OVER THE EASTERN U.S.
THAT ALLOWS HIGH PRESSURE TO SPILL INTO THE MID MS VALLEY. THIS
COULD LIMIT HIGHS TO THE 70S OVER THE WEEKEND WITH LOWS IN THE 50S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1232 PM CDT SUN JUL 21 2013
UPPER LEVEL WAVE ROLLING EASTWARD ACRS WEST CENTRAL INTO NORTH
CENTRAL IA ATTM...KICKING UP SHOWERS ON IT/S EASTWARD FLANK AND
THUNDERSTORMS ON IT/S SOUTHERN FLANK ACRS SOUTH CENTRAL IA INTO SW
IA. AHEAD OF IT FOR THE TERMINALS JUST VFR LEVEL DEBRIS CLOUDS AND
SOUTHEAST BREEZE OF 5-10 KTS. THE SCTRD SHOWERS TO GET INTO THE
VCNTY OF CID AND DBQ BY MID AFTERNOON AND LAST THROUGH EARLY
EVENING. SOME EMBEDDED THUNDER EXPECTED IN THAT ACTIVITY AS WELL
AS THE AFTERNOON PROGRESSES. THUS SOME POCKETS OF MVFR AND
VARIABLE WIND GUSTS POSSIBLE THROUGH 7-8 PM THIS EVENING. HEAVIER
RAIN MAY PRODUCE BOUTS OF IFR VSBYS AFTER 3 PM CDT. THESE
CONDITIONS POSSIBLE FOR MLI AS WELL FROM LATE AFTERNOON THROUGH MID
EVENING...BUT A CHANCE MLI COULD REMAIN IN BETWEEN THE ACTION
ZONES TO THE NORTH AND SOUTH. THE SOUTHERN ACTION ZONE...THE
ACTIVITY NOW ACRS SOUTH CENTRAL IA COULD BE A IMPACT AT BRL BY LATE
AFTERNOON WITH BOUTS OF HEAVY RAIN/IFR VSBYS...LOWERED CIGS DOWN TO
MVFR AND POSSIBLE VARIABLE GUSTY WINDS UP TO 45 KTS PRODUCED BY
THE THUNDERSTORMS. CURRENT EXTRAPOLATION HAS THE BRL UNDER THE GUN
OF THE SOUTH CENTRAL IA STORMS FROM 3 PM THROUGH 6 PM...WITH
ADDITIONAL DEVELOPMENT LINGERING IN THAT AREA THROUGH MID EVENING.
AFTER PRECIP CLEARS LATER THIS EVENING AND INTO THE OVERNIGHT...SOME
MVFR AND POSSIBLE IFR FOG AT ALL TERMINALS TOWARD SUNRISE
ESPECIALLY AT THE TERMINALS THAT DO MANAGE TO GET IN ON SOME RAIN
THIS AFTERNOON/EVENING. WINDS BECOMING LIGHT AND VARIABLE OVERNIGHT
OR LIGHT EAST-SOUTHEAST. ..12..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...WOLF
SHORT TERM...WOLF
LONG TERM...SHEETS
AVIATION...12
AREA FORECAST DISCUSSION
NWS PADUCAH KY
456 PM CDT SUN JUL 21 2013
.UPDATE...
ISSUED AT 456 PM CDT SUN JUL 21 2013
AFTER LOOKING AT NEW HRRR MODEL REFLECTIVITY DATA AND 18Z NAM...IT
APPEARS HEAVY RAIN IS MORE LIKELY IN SW INDIANA...SE ILLINOIS...AND
NW KENTUCKY LATE TONIGHT INTO EARLY MONDAY. 850 MB LOW LEVEL FLOW IS
FORECAST TO STRENGTHEN TO AROUND 20 KNOTS...WITH STRONG INDICATIONS
OF A BACKBUILDING MCS. RAISED POPS FOR THE OVERNIGHT HOURS TO
CATEGORICAL OR LIKELY IN NE COUNTIES. THE ENSEMBLE MEANS OF THE SREF
AND GFS ALSO SHOW QPF BULLSEYES IN THAT AREA OVERNIGHT. SURFACE TO
850 MB CONVERGENCE AXIS IS FORECAST TO BE IN THAT AREA WITH A 500 MB
SHORTWAVE TROUGH JUST UPSTREAM.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
ISSUED AT 215 PM CDT SUN JUL 21 2013
MAIN FORECAST CONCERN TONIGHT IS HEAVY RAIN POTENTIAL. LOTS OF
MOISTURE AND INSTABILITY IS IN PLACE...ALONG WITH A BROAD AREA OF
WEAK LIFT. THE PRIMARY LIFTING MECHANISM IS A 500 MB SHORTWAVE
ADVANCING EAST/SOUTHEAST ACROSS CENTRAL MISSOURI. CONVECTION HAS
BEEN SLOWLY INCREASING THIS AFTERNOON ALONG AND SOUTH OF A WEAK WARM
FRONT THAT EXTENDS FROM THE LOWER OHIO VALLEY TO NORTHWEST
ARKANSAS.
THE STORMS WILL CONTINUE TO INCREASE THROUGH THE EARLY EVENING
HOURS...AIDED BY THE APPROACHING SHORTWAVE AND WARM FRONTAL
CONVERGENCE. WILL MENTION HEAVY RAIN IN GRIDS AND ZONES. LOW LEVEL
WIND SPEEDS ARE CURRENTLY A LITTLE LOWER THAN OPTIMUM FOR AN
ORGANIZED FLOODING THREAT. HOWEVER...RAP MODEL RUNS INDICATE SOME
INCREASE AND BACKING OF LOW LEVEL WINDS LATE TODAY AND THIS EVENING.
POTENTIAL FOR EXCESSIVE RAINFALL AND LOCAL FLOODING WILL NEED TO BE
MONITORED THROUGH EVENING.
LATER TONIGHT AND MONDAY MORNING...WEAKENING INSTABILITY AND
DECREASING UPPER SUPPORT SHOULD BRING A GRADUAL DECREASE IN COVERAGE
AND INTENSITY OF THE PRECIP. TEMPS ON MONDAY WILL DEPEND ON TIMING
OF PARTIAL CLEARING...WHICH SHOULD TAKE PLACE FROM WEST TO EAST AS
THE DAY GOES ON. WILL CONTINUE WITH PREVIOUS FORECASTS THAT ARE
CLOSER TO GFS MOS THAN THE COOLER NAM MOS. A RELATIVE LULL IN PRECIP
CHANCES IS EXPECTED MONDAY NIGHT.
ON TUESDAY...A COLD FRONT WILL MOVE SOUTHEAST INTO SOUTHERN ILLINOIS
AND SE MISSOURI BY LATE IN THE DAY. THE FRONT SHOULD ARRIVE DURING
PEAK HEATING AND INSTABILITY...SO WILL CONTINUE WITH POPS ABOVE MOS
GUIDANCE. PRECIP WATER VALUES WILL BE SOMEWHAT LOWER DUE TO A MORE
VEERED /WEST TO NORTHWEST/ DEEP LAYER FLOW...WHICH IS WHY POPS WILL
BE KEPT BELOW THE LIKELY CATEGORY. FLOW FIELDS WILL BE SOMEWHAT
STRONGER WITH THIS SYSTEM...SO THE POTENTIAL FOR ISOLATED SEVERE
STORMS EXISTS. CONVECTION SHOULD DIMINISH WITH THE PASSAGE OF THE
COLD FRONT ACROSS THE LOWER OHIO VALLEY LATE TUESDAY NIGHT.
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
ISSUED AT 215 PM CDT SUN JUL 21 2013
THE MODELS ARE IN GENERAL AGREEMENT WITH FRONT ALONG OUR SOUTHERN
BORDER BY 12Z WED. HOWEVER THE GFS AND THE NAM PUSH IT ON THROUGH
LIMITING ANY PRECIP CHC AFTER 12Z WED. THE 00Z SUNDAY ECMWF LINGERS
PRECIP OVER THE AREA ALL DAY WED. CURRENT GRIDS REFLECT HIGHEST PROB
WOULD BE OVER SEMO AND LATEST RUNS SUPPORT THAT. HOWEVER WILL TRY TO
LOWER POPS NORTH AND EAST AS PREVIOUS SHIFT DID AND CONTINUE THE
TREND TOWARD A DRIER WED. IF THE 12Z ECMWF FOLLOWS THAT TREND THE
MID SHIFT WILL BE ABLE TO BETTER DEFINE THE CHC. SO THIS TIME FRAME
REMAINS A LITTLE SUSPECT FOR NOW WITH EITHER NORTH WINDS VIA NAM GFS
OR STALLED FRONT ECMWF. THE 12Z UKMET SHOWS THE FRONT ALONG THE
SOUTHERN BORDER AS WELL BUT THE RUN ENDS AT 12Z BUT APPEARS TO FAVOR
THE WETTER ECMWF.
FOR THE LATE WEEK CHC THE THE GFS BRINGS A FRONT THROUGH BUT THE
ECMWF AND DGEX BRING AN MCS OUT OF THE CENTRAL PLAINS FRIDAY WITH A
COLD FRONT IN ITS WAKE SATURDAY. THE GFS IS A LITTLE VOID OF THE MCS
FEATURE AND WILL LEAN TOWARD THE ECMWF AND DGEX SOLUTION...BUT USE
THE SLOWER TIMING OF THE ECMWF FOR THIS FEATURE. WILL MAINTAIN A
SLGT CHC SAT NGT IN THE EAST. WILL KEEP SUNDAY DRY WITH MUCH COOLER
AND DRIER AIR COMING INTO THE REGION.
AS FOR TEMPS IF THE EXTENDED INIT COMES TO FRUITION IT WILL BE A
MUCH COOLER AND WE COULD SEE SOME RECORD OR NEAR RECORD COOL TEMPS
EARLY NEXT WEEK. THE OPPOSITE OF LAST SUMMER RECORD SETTING HEAT.
&&
.AVIATION...
ISSUED AT 1230 PM CDT SUN JUL 21 2013
AREAS OF LOW CLOUDS WILL CONTINUE TO LIFT THIS AFTERNOON...WITH
LINGERING POCKETS OF MVFR CIGS BECOMING VFR EARLY. WITH DIURNAL
HEATING AND DESTABILIZATION...SHOWERS AND STORMS WILL SLOWLY
INCREASE IN COVERAGE AND INTENSITY THIS AFTERNOON. EXPECT PEAK
COVERAGE TO OCCUR EARLY THIS EVENING...ENHANCED BY AN UPPER LEVEL
DISTURBANCE APPROACHING FROM THE WEST. IT IS TOO EARLY TO PINPOINT
THE TIMING OF STORMS...BUT IT APPEARS LIKELY EACH TAF SITE WILL
RECEIVE AT LEAST SOME RAIN THIS AFTERNOON OR EVENING. BRIEF IFR
CONDITIONS ARE POSSIBLE IN ANY STORMS.
CONVECTION SHOULD FADE WITH LOSS OF HEATING...AND MAINLY DRY
CONDITIONS ARE EXPECTED OVERNIGHT. SOME LIGHT FOG OR PATCHY LOW
CLOUDS ARE POSSIBLE LATE AT NIGHT AND MONDAY MORNING. DIURNAL CU
WILL FORM AGAIN BY MIDDAY MONDAY.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...MY
SHORT TERM...MY
LONG TERM...KH
AVIATION...MY
AREA FORECAST DISCUSSION
NWS JACKSON KY
546 PM EDT SUN JUL 21 2013
.UPDATE...
ISSUED AT 544 PM EDT SUN JUL 21 2013
A CONTINUED LINE OF SCT TRAINING STORMS EXTENDS ACROSS THE NORTHERN
HALF OF THE CWA ALONG SOME WEAK HORIZONTAL BOUNDARY. PREVIOUS
FORECAST HAD SHOWERS ENDING OVER THE NW...BUT SO LONG AS THIS
BOUNDARY REMAINS IN PLACE...EXPECT ISOLATED TO SCT SHOWERS AND
THUNDERSTORMS TO CONTINUE OVER THIS AREA FOR THE NEXT COUPLE HOURS.
ALSO ADDED IN SOME ISOLATED POPS FOR SOME AREAS OVERNIGHT...MAINLY
BEFORE MIDNIGHT...BASED ON LATEST HI RES MODEL RUNS AND CURRENT
FORECAST TRENDS. ADDED CURRENT OBSERVATIONS INTO ONGOING FORECAST AS
WELL.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 325 PM EDT SUN JUL 21 2013
MORNING SHOWERS AND THUNDERSTORMS HAVE SHIFTED OFF TO THE SOUTH...BUT
THANKS TO SOME HEATING ACROSS THE EAST...ADDITIONAL SHOWERS AND
THUNDERSTORMS HAVE DEVELOPED TO THE EAST OF JACKSON...TOWARDS
PRESTONSBURG AND INEZ. THIS ACTIVITY WILL SLOWLY PUSH EAST THROUGH
THE REST OF THE AFTERNOON AND EVENING BEFORE EXITING EASTERN
KENTUCKY. IN THE WAKE OF THIS ACTIVITY IT LOOKS LIKE A FAIRLY QUIET
MID TO LATE EVENING IS ANTICIPATED AS SUBSIDENCE AHEAD OF THE
APPROACHING TROUGH AXIS ACROSS THE CENTRAL PLAINS TAKES HOLD. HRRR IS
IN LINE WITH CONDITIONS QUIETING DOWN THIS EVENING. WITH THE SYNOPTIC
FORCING OVERSPREADING THE AREA LATE TONIGHT INTO TOMORROW
MORNING...WILL BRING A PERIOD OF HIGH POPS BACK INTO THE FORECAST.
GIVEN THE RAIN THIS AFTERNOON...AND POTENTIAL HEAVY RAIN WITH THE
SYNOPTIC FEATURE LATE TONIGHT...GOING TO CONTINUE ON WITH THE FLASH
FLOOD WATCH. IN FACT...THE NAM SPITS OUT MORE THAN AN INCH OF RAIN
ACROSS A GOOD CHUNK OF THE AREA LATE TONIGHT AND TOMORROW...SO THE
POTENTIAL FOR HEAVY RAIN CONTINUES. THIS IS ESPECIALLY TRUE WITH
PWATS SITTING UP AROUND 1.8-2.0 INCHES. GOOD SHOWER AND THUNDERSTORM
COVERAGE SHOULD CONTINUE TOMORROW AS THE MID LEVEL WAVE PUSHES EAST
ACROSS THE AREA. COVERAGE SHOULD DIMINISH TOMORROW EVENING INTO THE
NIGHTTIME HOURS...ALTHOUGH SHOWERS AND THUNDERSTORMS COULD CONTINUE
THROUGH TOMORROW NIGHT AS WELL. CERTAINLY AN ACTIVE PERIOD SETTING
UP.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 325 PM EDT SUN JUL 21 2013
THE MODELS ESSENTIALLY AGREE ON THE GENERAL EVOLUTION OF MID LEVEL
TROUGHING OVER THE OHIO VALLEY AND GREAT LAKES THROUGH THE EXTENDED.
HOWEVER...THERE REMAINS MUCH DISAGREEMENT WITH RESPECT TO TIMING AND
TRACKS OF THE VARIOUS SHORTWAVES THAT WILL MOVE THROUGH THE AREA
LATER THIS WEEK AND INTO NEXT WEEKEND. THE ECMWF TAKES A KEY ONE OF
THESE INTO THE OHIO VALLEY ON WEDNESDAY HELPING TO BOTTOM OUT THIS
FIRST ITERATION OF A TROUGH. ANOTHER FOLLOWS...THOUGH...RIGHT ON THE
HEELS OF THE FIRST...THAT NIGHT WHICH WILL SERVE TO SHIFT THE TROUGH
EAST OF KENTUCKY ALLOWING SOME BRIEF HEIGHT RISES INTO THE CWA TO
CLOSE OUT THE WORK WEEK. HEIGHTS WILL START TO FALL AGAIN ON
SATURDAY WHEN A RATHER STRONG WAVE WILL MOVE DUE EAST OUT OF THE
CENTRAL PLAINS AND TOWARD THE OHIO VALLEY. UNLIKE YESTERDAY...THIS
FEATURE HAS GAINED SOME SUPPORT FROM THE GFS...JUST NOT AS STRONG.
IN CONJUNCTION WITH THIS SATURDAY WAVE...ANOTHER SWEEPS DOWN FROM
SOUTH CENTRAL CANADA LATER THAT NIGHT INTO EARLY SUNDAY RESTORING A
DEEP TROUGH OVER THE REGION. GIVEN THE SIMILARITIES IN THE OVERALL
PATTERN...WILL FAVOR A CONSENSUS OF THE OPERATIONAL GFS AND ECMWF
SOLUTIONS AS A STARTING POINT FOR THE EXTENDED GRIDS.
SENSIBLE WEATHER WILL FEATURE A CONTINUATION OF THE SOUPY AND
UNSETTLED CONDITIONS FROM THE SHORT TERM INTO THE DAY TUESDAY. THIS
WILL MEAN A THREAT OF CONVECTION AND POSSIBLY EXCESSIVE RAIN FALL.
A FRONTAL BOUNDARY WILL START TO MOVE SOUTH THROUGH THE AREA LATER
THAT NIGHT AND ON WEDNESDAY AS LOW PRESSURE CONSOLIDATES OVER THE
MID ATLANTIC COASTAL STATES. HIGH PRESSURE AND SOMEWHAT DRIER AIR
WILL MOVE INTO KENTUCKY ON THURSDAY AND PROVIDE A WELCOMED CHANGE OF
AIR MASS AND BREAK FROM THE SHOWER AND THUNDERSTORM THREATS. THIS
HIGH WILL MOVE EAST ON FRIDAY AND FRIDAY NIGHT AS A NEW AREA OF LOW
PRESSURE TAKES SHAPE OVER THE CENTRAL PLAINS LOOKING TO SLIP INTO
KENTUCKY ON SATURDAY. THIS WILL BRING RENEWED CHANCES OF SHOWERS AND
THUNDERSTORMS TO EAST KENTUCKY FOR THE WEEKEND...ALONG WITH SOMEWHAT
COOLER TEMPS. THE SFC LOW ASSOCIATED WITH THIS LOOKS TO PASS THROUGH
ON SUNDAY WITH THE BEST PCPN EXITING LATER IN THE DAY...WHILE THE
COOLER AIR REMAINS TO START THE NEW WORK WEEK.
THE CR GRID LOAD CAME IN REASONABLE CONSIDERING THE DIFFERENCES IN
THE SPECIFICS FROM THE MODELS. DID NUDGE DOWN POPS A BIT FROM
THURSDAY INTO FRIDAY NIGHT...MORE TOWARD THE 00Z OPERATIONAL ECMWF.
ALSO...ADJUSTED OVERNIGHT LOWS A TAD FOR WEDNESDAY AND THURSDAY
NIGHTS TO HIGHLIGHT RIDGE AND VALLEY TEMPERATURE DIFFERENCES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 135 PM EDT SUN JUL 21 2013
A FRONTAL BOUNDARY DRAPED ACROSS THE AREA WILL CONTINUE TO PRODUCE
OCCASIONAL SHOWERS AND THUNDERSTORMS THROUGH THE REST OF TODAY. WHILE
A BREAK MAY OCCUR THIS EVENING...A SHORT WAVE TROUGH WILL PUSH ACROSS
THE AREA LATE TONIGHT INTO MONDAY BRINGING MORE WIDESPREAD RAIN TO
THE AREA. AS FOR THE REST OF THE DAY...BASED ON CURRENT RADAR
TRENDS...WOULD NOT ANTICIPATE MANY RESTRICTIONS AT THE TAF SITES AS
KLOZ AND SME ARE STUCK IN LIGHT RAIN AT THE MOMENT. BETTER
VISIBILITY/CEILING RESTRICTIONS WILL ARRIVE WITH THE SHORTWAVE LATE
TONIGHT AND DROPPED VISIBILITIES TO BETWEEN 1 AND 3 MILES WITH SOME
LOWER CIGS. WE WILL PROBABLY SEE A PERIOD OF LOWER VISIBILITIES AND
CEILINGS BUT WILL LET FUTURE TAF FORECAST HANDLE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR KYZ044-050>052-
058>060-068-069-079-080-083>088-104-106>120.
&&
$$
UPDATE...JMW
SHORT TERM...KAS
LONG TERM...GREIF
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
325 PM EDT SUN JUL 21 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 325 PM EDT SUN JUL 21 2013
MORNING SHOWERS AND THUNDERSTORMS HAVE SHIFTED OFF TO THE SOUTH...BUT
THANKS TO SOME HEATING ACROSS THE EAST...ADDITIONAL SHOWERS AND
THUNDERSTORMS HAVE DEVELOPED TO THE EAST OF JACKSON...TOWARDS
PRESTONSBURG AND INEZ. THIS ACTIVITY WILL SLOWLY PUSH EAST THROUGH
THE REST OF THE AFTERNOON AND EVENING BEFORE EXITING EASTERN
KENTUCKY. IN THE WAKE OF THIS ACTIVITY IT LOOKS LIKE A FAIRLY QUIET
MID TO LATE EVENING IS ANTICIPATED AS SUBSIDENCE AHEAD OF THE
APPROACHING TROUGH AXIS ACROSS THE CENTRAL PLAINS TAKES HOLD. HRRR IS
IN LINE WITH CONDITIONS QUIETING DOWN THIS EVENING. WITH THE SYNOPTIC
FORCING OVERSPREADING THE AREA LATE TONIGHT INTO TOMORROW
MORNING...WILL BRING A PERIOD OF HIGH POPS BACK INTO THE FORECAST.
GIVEN THE RAIN THIS AFTERNOON...AND POTENTIAL HEAVY RAIN WITH THE
SYNOPTIC FEATURE LATE TONIGHT...GOING TO CONTINUE ON WITH THE FLASH
FLOOD WATCH. IN FACT...THE NAM SPITS OUT MORE THAN AN INCH OF RAIN
ACROSS A GOOD CHUNK OF THE AREA LATE TONIGHT AND TOMORROW...SO THE
POTENTIAL FOR HEAVY RAIN CONTINUES. THIS IS ESPECIALLY TRUE WITH
PWATS SITTING UP AROUND 1.8-2.0 INCHES. GOOD SHOWER AND THUNDERSTORM
COVERAGE SHOULD CONTINUE TOMORROW AS THE MID LEVEL WAVE PUSHES EAST
ACROSS THE AREA. COVERAGE SHOULD DIMINISH TOMORROW EVENING INTO THE
NIGHTTIME HOURS...ALTHOUGH SHOWERS AND THUNDERSTORMS COULD CONTINUE
THROUGH TOMORROW NIGHT AS WELL. CERTAINLY AN ACTIVE PERIOD SETTING
UP.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 325 PM EDT SUN JUL 21 2013
THE MODELS ESSENTIALLY AGREE ON THE GENERAL EVOLUTION OF MID LEVEL
TROUGHING OVER THE OHIO VALLEY AND GREAT LAKES THROUGH THE EXTENDED.
HOWEVER...THERE REMAINS MUCH DISAGREEMENT WITH RESPECT TO TIMING AND
TRACKS OF THE VARIOUS SHORTWAVES THAT WILL MOVE THROUGH THE AREA
LATER THIS WEEK AND INTO NEXT WEEKEND. THE ECMWF TAKES A KEY ONE OF
THESE INTO THE OHIO VALLEY ON WEDNESDAY HELPING TO BOTTOM OUT THIS
FIRST ITERATION OF A TROUGH. ANOTHER FOLLOWS...THOUGH...RIGHT ON THE
HEELS OF THE FIRST...THAT NIGHT WHICH WILL SERVE TO SHIFT THE TROUGH
EAST OF KENTUCKY ALLOWING SOME BRIEF HEIGHT RISES INTO THE CWA TO
CLOSE OUT THE WORK WEEK. HEIGHTS WILL START TO FALL AGAIN ON
SATURDAY WHEN A RATHER STRONG WAVE WILL MOVE DUE EAST OUT OF THE
CENTRAL PLAINS AND TOWARD THE OHIO VALLEY. UNLIKE YESTERDAY...THIS
FEATURE HAS GAINED SOME SUPPORT FROM THE GFS...JUST NOT AS STRONG.
IN CONJUNCTION WITH THIS SATURDAY WAVE...ANOTHER SWEEPS DOWN FROM
SOUTH CENTRAL CANADA LATER THAT NIGHT INTO EARLY SUNDAY RESTORING A
DEEP TROUGH OVER THE REGION. GIVEN THE SIMILARITIES IN THE OVERALL
PATTERN...WILL FAVOR A CONSENSUS OF THE OPERATIONAL GFS AND ECMWF
SOLUTIONS AS A STARTING POINT FOR THE EXTENDED GRIDS.
SENSIBLE WEATHER WILL FEATURE A CONTINUATION OF THE SOUPY AND
UNSETTLED CONDITIONS FROM THE SHORT TERM INTO THE DAY TUESDAY. THIS
WILL MEAN A THREAT OF CONVECTION AND POSSIBLY EXCESSIVE RAIN FALL.
A FRONTAL BOUNDARY WILL START TO MOVE SOUTH THROUGH THE AREA LATER
THAT NIGHT AND ON WEDNESDAY AS LOW PRESSURE CONSOLIDATES OVER THE
MID ATLANTIC COASTAL STATES. HIGH PRESSURE AND SOMEWHAT DRIER AIR
WILL MOVE INTO KENTUCKY ON THURSDAY AND PROVIDE A WELCOMED CHANGE OF
AIR MASS AND BREAK FROM THE SHOWER AND THUNDERSTORM THREATS. THIS
HIGH WILL MOVE EAST ON FRIDAY AND FRIDAY NIGHT AS A NEW AREA OF LOW
PRESSURE TAKES SHAPE OVER THE CENTRAL PLAINS LOOKING TO SLIP INTO
KENTUCKY ON SATURDAY. THIS WILL BRING RENEWED CHANCES OF SHOWERS AND
THUNDERSTORMS TO EAST KENTUCKY FOR THE WEEKEND...ALONG WITH SOMEWHAT
COOLER TEMPS. THE SFC LOW ASSOCIATED WITH THIS LOOKS TO PASS THROUGH
ON SUNDAY WITH THE BEST PCPN EXITING LATER IN THE DAY...WHILE THE
COOLER AIR REMAINS TO START THE NEW WORK WEEK.
THE CR GRID LOAD CAME IN REASONABLE CONSIDERING THE DIFFERENCES IN
THE SPECIFICS FROM THE MODELS. DID NUDGE DOWN POPS A BIT FROM
THURSDAY INTO FRIDAY NIGHT...MORE TOWARD THE 00Z OPERATIONAL ECMWF.
ALSO...ADJUSTED OVERNIGHT LOWS A TAD FOR WEDNESDAY AND THURSDAY
NIGHTS TO HIGHLIGHT RIDGE AND VALLEY TEMPERATURE DIFFERENCES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 135 PM EDT SUN JUL 21 2013
A FRONTAL BOUNDARY DRAPED ACROSS THE AREA WILL CONTINUE TO PRODUCE
OCCASIONAL SHOWERS AND THUNDERSTORMS THROUGH THE REST OF TODAY. WHILE
A BREAK MAY OCCUR THIS EVENING...A SHORT WAVE TROUGH WILL PUSH ACROSS
THE AREA LATE TONIGHT INTO MONDAY BRINGING MORE WIDESPREAD RAIN TO
THE AREA. AS FOR THE REST OF THE DAY...BASED ON CURRENT RADAR
TRENDS...WOULD NOT ANTICIPATE MANY RESTRICTIONS AT THE TAF SITES AS
KLOZ AND SME ARE STUCK IN LIGHT RAIN AT THE MOMENT. BETTER
VISIBILITY/CEILING RESTRICTIONS WILL ARRIVE WITH THE SHORTWAVE LATE
TONIGHT AND DROPPED VISIBILITIES TO BETWEEN 1 AND 3 MILES WITH SOME
LOWER CIGS. WE WILL PROBABLY SEE A PERIOD OF LOWER VISIBILITIES AND
CEILINGS BUT WILL LET FUTURE TAF FORECAST HANDLE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR KYZ044-050>052-
058>060-068-069-079-080-083>088-104-106>120.
&&
$$
SHORT TERM...KAS
LONG TERM...GREIF
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
401 PM EDT SUN JUL 21 2013
.SYNOPSIS...
HIGH PRESSURE REMAINS ANCHORED OFF THE SOUTHEAST COAST DURING THE
EARLY PORTION OF THIS WEEK...AS A COLD FRONT BECOMES NEARLY
STATIONARY FROM THE OHIO VALLEY TO THE NORTHERN MID ATLANTIC STATES.
MEANWHILE...AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL PERSIST
ACROSS THE REGION.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
CURRENT SATELLITE IMAGERY AND REGIONAL RADAR MOSAIC INDICATE AN
ORGANIZED LINE OF THUNDERSTORMS EXTENDING FROM NORTHERN VA SW ALONG
THE PIEDMONT AND MOVING EAST. THIS LINE OF STORMS IS BEGIN DRIVEN BY
THE TAIL END OF A SHORTWAVE TROUGH MOVING ACROSS THE NORTHERN MID
ATLANTIC...INTERACTING WITH A SURFACE TROUGH OVER THE AREA...AND
FEEDING OFF AN AXIS OF >2500 J/KG OF MLCAPE PER SPC HRRR BASED
MESOANALYSIS. ADDITIONAL SEA/BAY BREEZE CONVECTION IS DEVELOPING
ACROSS THE LOWER BAY AND MD ATLANTIC COAST.
THE PRIMARY LINE SHOULD PROGRESS EAST ACROSS CENTRAL/S-CENTRAL VA
THROUGH THE LATE AFTERNOON AND EARLY EVENING. INITIALLY...0-6KM BULK
SHEAR VALUES ARE PROGGED TO BE ~25KT BEFORE DECAYING BY EARLY
EVENING. THEREFORE...THE BEST CHANCE OF AN ISOLATED SEVERE STORM
(MAINLY WIND GUST) WOULD BE ACROSS THE NORTHERN PORTION OF THE AREA
THROUGH THE REMAINDER OF THE AFTERNOON. THE SOUTHERN END OF THE LINE
SHOULD EVENTUALLY DISSIPATE THIS EVENING DUE TO THE LOSS OF SURFACE
HEATING AND A LACK OF LARGE SCALE FORCING AS THE SHORTWAVE ENERGY
PULLS TOWARD NEW ENGLAND. FARTHER NE IN THE LOCAL AREA...SCT POPS
WILL BE MAINTAINED THROUGH THE EVENING/EARLY OVERNIGHT IN CLOSER
PROXIMITY TO THE SHORTWAVE. WARM AND HUMID CONDITIONS WILL PERSIST
OVERNIGHT WITH LOWS IN THE LOW/MID 70S.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
THE OVERALL PATTERN REMAINS UNSETTLED MONDAY AS A SURFACE
BOUNDARY/WEAK LOW STALL OVER THE AREA. ADDITIONALLY...A VIGOROUS
TROUGH CARVES OVER THE GREAT LAKES. A LEADING SHORTWAVE EJECTS OUT
OF THE TROUGH ACROSS THE OHIO VALLEY TOWARD THE APPALACHIANS MONDAY
AFTERNOON/EVENING. HENCE...HIGH CHANCE/LOW-END LIKELY POPS ARE
FORECAST MONDAY AFTN/EVENING. AFTERNOON HIGHS WILL TREND DOWN
SLIGHTLY DUE TO INCREASED CLOUD COVER AND A HIGHER PROBABILITY OF
SHOWERS/TSTMS (AND SHIFTING WIND DIRECTION MAINLY N)...ALTHOUGH
DEWPOINTS WILL REMAIN IN THE LOW/MID 70S. HIGHS SHOULD RANGE FROM
THE MID/UPPER 80S TO AROUND 90 MONDAY. ANY SEVERE THREAT LOOKS
RATHER LIMITED MONDAY...WITH THE MAIN CONCERN AGAIN BEING HEAVY RAIN
FROM SLOW MOVING STORMS.
THE PARENT TROUGH PIVOTS N OF THE GREAT LAKES TUESDAY AS A SECONDARY
WAVE LIFTS ACROSS THE MID ATLANTIC. THE LATEST DATA BRINGS THE WAVE
THROUGH EARLIER IN THE DAY...FOLLOWED BY WESTERLY MID-LEVEL FLOW BY
LATER AFTERNOON. GIVEN THIS...POPS HAVE BEEN LOWERED...ESPECIALLY W.
HOWEVER..A WELL-DEFINED LEE SIDE TROUGH REMAINS OVER THE AREA...SO
WILL MAINTAIN 30 POPS W...TO 40 E. HIGHS SHOULD AVERAGE IN THE UPPER
80S TO LOW 90S.
THE 21/12Z GFS/NAM BRING YET ANOTHER SHORTWAVE TROUGH THROUGH THE
REGION WEDNESDAY. THE MAIN MOISTURE FEED MAY BE WELL OFF THE COAST
BY THIS TIME...SO WILL GO NO HIGHER THAN CHANCE POPS AT THIS TIME.
HIGHS SHOULD AGAIN RANGE FROM THE UPPER 80S TO LOW 90S. LOWS THROUGH
THE PERIOD SHOULD RANGE FROM 70-75.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
UPR TROF OVR THE ERN THIRD OF THE U.S. WED NGT THRU THU...WILL SHIFT
EWRD AND OFFSHR THU NGT THRU FRI. THIS WILL PUSH FRNTL BNDRY ALNG OR
JUST OFFSHR AT THE BEGINNING OF THE PERIOD...FARTHER OUT TO SEA.
WEAK HI PRES WILL BLD INTO AND OVR THE AREA FOR FRI NGT INTO SAT.
THEN...ANOTHER SHRTWV TROF AND ASSOCIATED COLD FRONT WILL APPROACH
AND MOVE INTO THE REGION LATE SAT NGT THRU SUN. AT THIS TIME...WILL
NOT BE GOING ANY HIGHER THAN 20% OR 30% THRU THE PERIOD...DUE TO LOW
CONFIDENCE OF COVERAGE. MIN TEMPS WILL BE IN THE UPR 60S TO MID 70S
THU MORNG...AND MAINLY IN THE MID 60S TO LWR 70S FRI...SAT AND SUN
MORNGS. MAX TEMPS WILL GENERALLY BE IN THE MID TO UPR 80S THRU THE
PERIOD.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
AFTER SEVERAL HOURS OF OCNL MVFR CIGS AT EACH OF THE TAF SITES...VFR
IS EXPECTED TO PREVAIL DURING THE AFTN. THE FOCUS WILL TURN TO
SCATTERED CONVECTION ACROSS MUCH OF THE AREA. THIS IS MOST LIKELY TO
OCCUR AT RIC AND SBY WHERE TEMPO GROUPS FOR TSTMS ARE IN PLACE
TOWARD EARLY EVENING. CONFIDENCE IN THE TIMING FOR THE OTHER THREE
SITES IS NOT HIGH ENOUGH TO INCLUDE TSTMS AT THIS TIME. SOME MVFR IS
EXPECTED TO DEVELOP AGAIN MONDAY MORNING SIMILAR TO THE LAST SEVERAL
MORNINGS.
LOW PRESSURE ASSOCIATED WITH AN APPROACHING COLD FRONT HAS WEAKENED
RESULTING IN DIMINISHING WINDS OVER THE AREA. WINDS WILL BE LIGHT
AND VARIABLE DURING MUCH OF THE TAF PERIOD.
OUTLOOK...SCATTERED MAINLY AFTN AND EARLY EVENING TSTMS CAN BE
EXPECTED MON THROUGH FRI WITH THE HIGHEST CHANCES MON AND WED.
AVIATION CONDS MAY LWR BRIEFLY IN HEAVIER PCPN. PATCHY IFR FOG NEAR
SUNRISE CANNOT BE RULED BUT NO WIDESPREAD IFR IS INDICATED THROUGH
MID WEEK.
&&
.MARINE...
SUB-SCA CONDS WILL PREVAIL OVER THE NEXT SEVERAL DAYS OVER AREA
WATERS. SWELLS WILL IMPACT THE COASTAL WATERS DUE TO STRONGER WINDS
ASSOCIATED WITH THE BERMUDA HIGH WELL OFF THE COAST. ADDED SOME
HEIGHT TO THE SEAS DUE TO THE SWELL...ESPECIALLY MONDAY NIGHT AND
EARLY TUESDAY...BUT KEPT THEM BELOW 5 FT FOR OUR COASTAL ZONES.
EXPECT LOCALLY STRONGER WNDS IN SHOWERS AND TSTMS THRU THE PERIOD.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...AJZ/LKB
NEAR TERM...AJZ
SHORT TERM...AJZ/LKB
LONG TERM...TMG
AVIATION...LSA
MARINE...LSA
SHORT TERM FORECAST DISCUSSION FOR DETAILS ON CONVECTIVE INITIATION
AND SUPPORTING SEVERE WX PARAMETERS/INDICES ON MONDAY AFTERNOON. A
LOT OF WHAT HAPPENS MONDAY EVENING WILL BE DEPENDENT ON CONVECTIVE
EVOLUTION MONDAY AFTERNOON. THE BEST INSTABILITY APPEARS TO BE ALONG
A THETA-E AXIS JUST AHEAD OF THE SFC COLD FRONT OVER THE WESTERN
SHORE OF UPPER MI AT THE START OF THE PERIOD...SO DO NOT EXPECT
CONVECTION TO CLEAR OUT UNTIL THE FRONTAL PASSAGE. THE MAIN QUESTION
IS IF THE ENVIRONMENT ON MONDAY AFTERNOON REMAINS CAPPED ENOUGH TO
MAKE THE FIRST SUBTLE MID-LEVEL WAVE INERT AS IT PASSES OVERHEAD
EARLY MONDAY AFTERNOON. IF THIS IS THE CASE...EARLY MONDAY EVENING
COULD BE QUITE ACTIVE ALONG THE FRONT...ESPECIALLY NEAR THE WI
BORDER ONCE FRONTAL FORCING INITIATES MORE WIDESPREAD CONVECTION.
THE LACK OF MINIMAL AFTERNOON CONVECTION COULD ALLOW MLCAPE VALUES
TO REACH 1000 TO 1500 J/KG ACROSS THE WEST. WHILE THE BEST SHEAR
WILL HAVE DIMINISHED SOMEWHAT BY THIS POINT AS THE SFC FLOW VEERS TO
THE SW...40KTS OF 0-6KM SHEAR WILL BE MORE THAN ENOUGH TO SUPPORT
SUPERCELLS ALONG THE COLD FRONT. ALSO...WITH THE SHORTWAVE TROUGH
MOVING ESE...MID-LEVEL WESTERLY WINDS WILL CREATE ABOUT 60 DEGREES
OF SEPARATION BETWEEN THE SFC FRONT AND SHEAR VECTORS. SO...WOULD
NOT BE SURPRISED TO SEE A WINDOW OF DISCRETE SUPERCELLS ALONG THE WI
BORDER IN THE EARLY EVENING. AS FOR THE MAIN SEVERE THREAT...THINGS
GET A LITTLE TRICKY GIVEN VEERING SFC FLOW AND FREEZING LEVELS AOA
14KFT. WITH DOWNDRAFT CAPE APPROACHING 1000 J/KG ALONG THE BORDER
AMIDST DECENT MID-LEVEL DRY AIR...THINKING IS THAT STRONG WINDS WILL
BE THE MAIN THREAT. SMALL MICROBURSTS FROM RFD/S ON ANY SUPERCELLS
THAT FORM...AND SMALL BOWING SEGMENTS WILL BE OF MOST CONCERN.
OVERALL...STILL THINK SEVERE CONVECTION THREAT IS MARGINAL AND QUITE
CONDITIONAL...BUT PARAMETERS ARE LINING UP WELL ENOUGH TO AT LEAST
DISCUSS THE POTENTIAL.
THE 12Z NAM FORECAST HAS COMPLETE FRONTAL PASSAGE THROUGH THE CWA
AND COASTAL WATERS OF LAKE MI BY 09Z TUESDAY. THOUGH...A BIT OF
ELEVATED INSTABILITY COMBINED WITH A SECONDARY MID-LEVEL TROUGH
CROSSING THE CWA BEHIND THE FRONT SUGGEST KEEPING AT LEAST
SLIGHT CHANCE POPS ACROSS THE WEST AND CENTRAL UNTIL SUNRISE
TUESDAY. ANY OF THIS PRECIP WILL BE ENTIRELY SHORTWAVE-DRIVEN.
TUESDAY THROUGH WEDNESDAY...WEAK MID-LEVEL RIDGING ON NORTHWEST FLOW
WILL BRING QUIET AND DRY CONDITIONS BY MID-WEEK. TUESDAY AND
TUESDAY NIGHT LOOK TO BE A CARBON COPY OF YESTERDAY AND LAST NIGHT.
HAVE LOWERED TEMPS IN BOTH PERIODS GIVEN LIGHT WINDS AND DRY AIR.
PWAT VALUES UNDER 0.5 INCHES TUESDAY NIGHT WILL ALLOW FOR GOOD
RADIATIONAL COOLING. THE MODELS THAT HANDLED LAST NIGHTS COOL TEMPS
THE BEST ARE SHOWING LOW 40S ACROSS THE INTERIOR WEST.
THEREFORE...DROPPED TEMPS SEVERAL DEGREES. BRISK NNW FLOW BEHIND THE
COLD FRONT WILL ALSO BRING AN ELEVATED SWIM RISK EAST OF MARQUETTE
THROUGHOUT THE DAY. BY WEDNESDAY...A WEAK SHORTWAVE TROUGH WILL
BEGIN TRACKING SOUTHEAST ACROSS NORTH MANITOBA ON THE BACKSIDE OF
THE DEEP EASTERN CANADIAN TROUGH. THE GEM AND GFS ARE DEPICTING A
CONVECTIVELY-INDUCED SHORTWAVE DIGGING SOUTHEAST INTO WI WEDNESDAY
AFTERNOON...BUT FALLING APART AS IT RUNS INTO THE RIDGE. THIS
FOLLOWS THE TRACK OF WEAKLY COUPLED UPPER JETS OVER THE UPPER TO MID
MS VALLEY. KEPT ANY MENTION OF PRECIP OUT OF THE DAY ON
WEDNESDAY...BUT THE TREND OF THIS FORECAST WILL NEED TO BE MONITORED
OVER THE NEXT COUPLE DAYS.
THURSDAY AND FRIDAY...A FEW DIURNAL SHOWERS AND STORMS ARE POSSIBLE
THURSDAY AFTERNOON ACROSS THE INTERIOR WEST WITH RETURN SFC MOISTURE
ON THE BACKSIDE OF THE SFC HIGH. THE REST OF THE LAYER WILL REMAIN
SOMEWHAT DRY...SO WILL KEEP THE CHANCE POPS FOR NOW. USED CONSENSUS
POPS FOR FRIDAY AS THE MODELS BECOME DIFFERENT ON HOW THEY HANDLE
THE INCOMING TROUGH FROM MANITOBA. THE GFS HAS THE TROUGH BECOMING
QUITE AMPLIFIED AND BRINGS A SFC COLD FRONT THROUGH THE CWA THURSDAY
NIGHT. MEANWHILE...THE ECMWF IS FAR LESS-AMPLIFIED WITH THE TROUGH
AND DOES NOT PASS THE FRONT UNTIL FRIDAY MORNING. THE GEM IS EVEN
SLOWER...BRINGING THE FRONT THROUGH FRIDAY AFTERNOON.
SATURDAY AND SUNDAY...SHARP MID-LEVEL RIDGING DEVELOPING ACROSS THE
NORTHERN PLAINS WILL BEGIN TO WORK INTO THE UPPER GREAT LAKES BEHIND
THE DEPARTING TROUGH. BEING LESS AMPLIFIED...THE ECMWF TAKES LONGER
TO PASS THE TROUGH ACROSS THE REGION...AND ACTUALLY STALLS IT OVER
LAKE HURON AT THE VERY END OF THE PERIOD. GIVEN THE
UNCERTAINTIES...WILL MAINTAIN CONSENSUS POPS FOR NEXT WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 154 PM EDT SUN JUL 21 2013
VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH THE FCST PERIOD.
EXPECT INCREASING MID CLOUDS LATE IN THE DAY AND TONIGHT AHEAD OF AN
APPROACHING DISTURBANCE. SOME SHRA ARE POSSIBLE AT KIWD AND KCMX LATE
TONIGHT. SOME LOWER CIGS NEAR MVFR MAY BE POSSIBLE LATE TONIGHT AND
MON MORNING AS LOW LEVEL MOISTURE ADVECTION INCREASES.
HOWEVER...CONFIDENCE WAS TOO LOW MENTION IN THE TAF AT THIS TIME.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 410 PM EDT SUN JUL 21 2013
SRLY WINDS WILL INCREASE TO AROUND 20 KNOTS LATE TONIGHT AND MONDAY
AHEAD OF A LOW PRESSURE TROUGH MOVING THROUGH THE AREA. NORTH TO
NORTHWEST WINDS WILL THEN INCREASE TO 20-25 KNOTS BY LATE MONDAY NIGHT
INTO TUESDAY BEHIND THE TROUGH/COLD FRONT MOVING THROUGH THE REGION.
WINDS ARE THEN EXPECTED TO REMAIN BELOW 20 KNOTS TUE NIGHT THROUGH
THURSDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KLUBER
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
155 PM EDT SUN JUL 21 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 450 AM EDT SUN JUL 21 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A ZONAL FLOW OVER THE UPPER
GREAT LAKES. AT THE SFC...HIGH PRESSURE DOMINATES THE UPPER GREAT
LAKES. THE CLEAR SKIES AND LIGHT WINDS HAVE ALLOWED TEMPS EARLY THIS
MORNING TO FALL INTO THE 40S WITH EVEN A FEW LOCATIONS REACHING THE
MID TO UPPER 30S.
TODAY...AS THE SFC HIGH SHIFTS EAST OF THE AREA...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 INDICATE SOME INCREASE IN 305K ISENTROPIC ASCENT OVER FAR WRN
UPR MI LATE IN THE DAY ALTHOUGH BEST MOISTURE LIFT SHOULD STAY SOUTH
AND WEST. WILL MAINTAIN GOING FCST OF SLIGHT CHANCE POPS OVER THE
FAR WEST.
TONIGHT...INCREASING 925-700 MB THETA-E ADVECTION AND 305K
ISENTROPIC ASCENT SHOULD LEAD TO INCREASED CHCS FOR SHRA AND TSRA
ESPECIALLY AFT MIDNIGHT AS SHORTWAVE APPROACHED FM THE WEST.
LIMITING FACTOR FOR TSRA WILL BE LACK OF ELEVATED INSTABILITY AS
MUCAPES ONLY A FEW HUNDRED J/KG. WILL KEEP HIGHER CHC POPS OVER FAR
WEST AND TAPER TO LOW CHC 20-30 PCT POPS OVER CENTRAL COUNTIES.
EXPECT LOWS GENERALLY IN THE 50S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 450 AM EDT SUN JUL 21 2013
MOST TIME SPENT ON LONG TERM WAS WITH PRECIP CHANCES MON/MON NIGHT
AND ASSESSING SEVERE STORM THREAT FOR MON AFTERNOON/EVENING.
LOOKING FIRST AT THE LARGE SCALE...AN UPPER TROUGH OVER THE ERN HALF
OF THE CONUS WILL BE STEMMING FROM A CLOSED LOW OVER NRN QUEBEC AND
AN UPPER RIDGE WILL BE OVER THE WRN CONUS AT 12Z MON. A PIECE OF
UPPER ENERGY WILL MOVE ACROSS THE REGION MON INTO EARLY MON
NIGHT...FOLLOWED BY OTHER SMALLER SCALE ENERGY THU NIGHT THROUGH
SAT...BUT THE OVERALL PATTERN REMAINS SIMILAR THROUGH THE EXTENDED.
THIS MEANS...FOR THE MOST PART...THAT COOLER WEATHER IS HERE TO STAY
FOR MUCH OF THE NEXT WEEK AT LEAST.
FOR THE SPECIFICS...
MON/MON NIGHT...THERE WILL BE PRECIP MOVING INTO THE WRN CWA EARLY
MON AS THE UPPER TROUGH AND SFC TROUGH/COLD FRONT MOVE IN. THINK THE
BEST PRECIP CHANCES WILL BE DURING THE AFTERNOON/EARLY EVENING AS
THE COLD FRONT MOVES THROUGH A POTENTIALLY UNSTABLE AIRMASS.
QUESTIONS IS HOW MUCH CLEARING WILL RESULT AFTER MORNING
RAIN...WHICH WILL EFFECT HOW MUCH INSTABILITY EXISTS IN THE
AFTERNOON. IF WE CAN GET GOOD CLEARING...SBCAPE VALUES MAY BE
800-1200J/KG /HIGHEST OVER SCENTRAL UPPER MI/...AND STRONGLY VEERING
WINDS THROUGH THE ATMOSPHERE WILL LEAD TO AROUND 40KTS OF 0-6KM BULK
SHEAR. IF OPTIMAL CONDITIONS FOR CONVECTION DO MATERIALIZE...THEN
SEVERE THUNDERSTORMS WITH LARGE HAIL AND DAMAGING WINDS WOULD BE
POSSIBLE...WITH THE BEST CHANCES OVER SCENTRAL UPPER MI.
HOWEVER...AT THIS TIME...THINK THE COVERAGE OF ANY SEVERE WEATHER
WILL BE MORE LIMITED DUE TO DRY AIR. FOR NOW WILL CONTINUE MENTION
OF SEVERE CHANCES IN HWO/EHWO BUT STILL TOO UNCERTAIN TO PUT IN
GRIDS. MON LOOKS LIKE THE WARMEST DAY IN THE NEXT WEEK AHEAD OF THE
COLD FRONT...WITH HIGHS IN THE 70S TO MID 80S.
POSTFRONTAL TUESDAY SHOULD BE COOLER AND SIMILAR TO YESTERDAY...WITH
HIGHS AROUND 60 NEAR LAKE SUPERIOR TO THE LOW 70S SOUTH CENTRAL.
SKIES SHOULD BE CLEARING BY THE AFTERNOON.
WED WILL BE SLIGHTLY WARMER THAN TUESDAY AS TEMPS RECOVER SOME FROM
THE COLD FRONT. SHOULD SEE SOME INCREASE IN CLOUDS FROM W TO E
DURING THE AFTERNOON/EVENING AS A MORE MILD PIECE OF UPPER ENERGY
SLIDES ACROSS THE CWA...BUT NO PRECIP IS EXPECTED.
THERE IS MORE UNCERTAINTY LATER IN THE WEEK WHEN LOOKING AT MORE
SIGNIFICANT UPPER ENERGY SLIDING INTO THE REGION...BUT PRECIP WILL
CERTAINLY BE POSSIBLE LATER INTO THE WEEK. TEMPERATURES WILL CLIMB
ANOTHER COUPLE OF DEGREES ON THURSDAY...BUT SHOULD AGAIN FALL INTO
THE WEEKEND AS THE UPPER TROUGH MOVES OVERHEAD. USED A GENERAL
CONSENSUS OF MODEL GUIDANCE FOR THIS PART OF THE FORECAST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 154 PM EDT SUN JUL 21 2013
VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH THE FCST PERIOD.
EXPECT INCREASING MID CLOUDS LATE IN THE DAY AND TONIGHT AHEAD OF AN
APPROACHING DISTURBANCE. SOME SHRA ARE POSSIBLE AT KIWD AND KCMX LATE
TONIGHT. SOME LOWER CIGS NEAR MVFR MAY BE POSSIBLE LATE TONIGHT AND
MON MORNING AS LOW LEVEL MOISTURE ADVECTION INCREASES.
HOWEVER...CONFIDENCE WAS TOO LOW MENTION IN THE TAF AT THIS TIME. &&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 450 AM EDT SUN JUL 21 2013
HIGH PRESSURE WILL KEEP WINDS GENERALLY LIGHT TODAY OVER THE
NORTHERN GREAT LAKES. SRLY WINDS WILL INCREASE TO AROUND 20 KNOTS
LATE TONIGHT AND MONDAY AHEAD OF A LOW PRESSURE TROUGH MOVING
THROUGH THE AREA. NORTH TO NORTHWEST WINDS WILL THEN INCREASE TO 20
KNOTS BY LATE MONDAY NIGHT INTO TUESDAY BEHIND THE TROUGH/COLD FRONT
MOVING THROUGH THE REGION. WINDS ARE THEN EXPECTED TO REMAIN BELOW
20 KNOTS TUE NIGHT THROUGH THURSDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...TITUS
AVIATION...JLB
MARINE...VOSS
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
123 PM CDT SUN JUL 21 2013
.UPDATE...
QUICK UPDATE TO ADJUST POPS FOR LATEST TRENDS...PRIMARILY TO RAISE TO
LIKELY CATEGORY S AND E AS CONVECTION CONTINUE TO BUILD/PROPAGATE N ALONG
N EDGE OF CONVECTIVE MASS TO OUR S. PER LAPS AND RUC ACTIVITY SHOULD
BE BUILDING INTO A MORE UNSTABLE AIRMASS WITH MAX OF SBLI NEAR -8
OVER EC MS. HENCE EXPECT ACTIVITY TO BECOME A BIT MORE ROBUST WITH
CONTINUED POTENTIAL FOR SOME STRONGER STORMS.
&&
.PREV DISCUSSION... /ISSUED 1028 AM CDT SUN JUL 21 2013/
UPDATE...
MAKING SOME ADJUSTMENTS TO THE FORECAST FOR THE FIRST COUPLE OF
PERIODS...INCLUDING ADJUSTING POPS A LITTLE FOR TODAY...CUTTING POPS
FOR TONIGHT...AND TWEAKING TEMPS UP A HAIR FOR THIS AFTERNOON.
SHORT TERM...
WATER VAPOR AND RUC STREAMLINE ANALYSIS SHOW REMNANT UPPER LEVEL LOW
CURRENTLY OVER THE LOWER DELTA REGION. SHORT TERM MODELS SHOW THIS
LOW OPENING UP AND DRIFTING EAST TODAY. BLENDED TOTAL PW PRODUCT
SHOWS BEST DEEP MOISTURE OVER S/E AREAS AHEAD OF UPPER LOW...BUT EVEN
RIGHT UNDER THE UPPER LOW WHERE A MIN IN MOISTURE EXISTS...PW VALUES
STILL AROUND 1.8 INCHES. CU IS BEGINNING TO FORM ACROSS THE
AREA...AND WITH CONTINUED HEATING AND SUPPORT FROM UPPER SYSTEM
EXPECT CONVECTIVE COVERAGE TO INCREASE THROUGH THE AFTERNOON. SHORT
TERM MESOSCALE MODELS AGREE ON BEST COVERAGE OVER S/E AREAS...AND
THIS GENERALLY SEEMS SUPPORTED BY LATEST TRENDS IN OBSERVATIONAL
DATA. DID TWEAK POPS UP A HAIR TO GET ALL AREAS TO AT LEAST 30 PCT
BUT OVERALL TREND OF GOING FORECAST LOOKS OK. MORNING SOUNDING
ANALYSIS AND LOCAL RUC MICROBURST PARAMETER SUGGEST THAT CURRENT
WORDING IN HWO AND GRAPHICAST OF SOME STRONG STORMS SEEMS REASONABLE.
RUC SHOWS 500 MB TEMPS COOLING A DEG OR TWO MOST OF AREA AS MID LEVEL
COLD POOL WITH UPPER LOW MOVES ACROSS...AND THIS SHOULD HELP ENHANCE
INSTABILITY AND LAPSE RATES A BIT. THUS WOULD CERTAINLY NOT RULE OUT
A COUPLE OF SEVERE STORMS THIS AFTERNOON...PARTICULARLY WITH ANY
CELL/BOUNDARY MERGERS. WITH PRETTY COMPLETE LACK OF CLOUDINESS BEFORE
BUILDING CU...TEMPS HAVE WARMED QUITE QUICKLY THIS MORNING. ADJUSTED
DIURNAL CURVE FOR MORE RAPID WARMUP AND TWEAKED MAXES UP A DEG OR
TWO.
WITH REGARD TO TONIGHT...THINKING THAT 00Z GFS MAY HAVE BEEN A WET
ANOMALY BASED ON GEFS GUIDANCE...LATEST 06Z GFS...AND 00Z ECMWF. MAIN
CONCERN FOR CONVECTION TONIGHT IS LIKELY WAVE THAT HAS BEEN PRODUCING
SOME CONVECTION OVER NE OK THIS MORNING...AND IT IS CERTAINLY
PLAUSIBLE THAT THIS SYSTEM COULD INCITE SOME OVERNIGHT CONVECTION
ESPECIALLY OVER NORTHERN AREAS. HOWEVER...HIGH CHANCE TO CATEGORICAL
POPS IN CURRENT FORECAST AS PROVIDED BY 00Z GFS SEEM A BIT
BULLISH...AND WILL REDUCE POPS BY 15-30 PCT AREA WIDE FOR TONIGHT.
&&
.AVIATION...
VFR CONDITIONS WERE BEING OBSERVED AT 14Z AND WILL PREVAIL AT ALL
SITES THROUGH 18Z. MODELS INDICATE GREATEST COVERAGE OF TSTMS THIS
AFTN/EVNG WL BE ACROSS THE SRN HALF OF THE AREA. BRIEF IFR CONDITIONS
CAN BE EXPECTED AROUND THE STORMS FROM 18Z-04Z. VFR CONDITIONS WL
RESUME AREAWIDE THIS EVNG AND CONTINUE THROUGH 09Z MON. AFTER
09Z...MVFR VSBYS WL BE PSBL MAINLY ACROSS THE SRN HALF OF THE AREA.
CONVECTION MAY GET AN EARLY START ACROSS THE NORTH MONDAY MORNING DUE
TO A DISTURBANCE IN THE NW FLOW ALOFT. /22/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 73 92 76 94 / 33 48 27 29
MERIDIAN 72 91 72 96 / 35 61 38 41
VICKSBURG 73 93 75 94 / 30 41 21 21
HATTIESBURG 72 92 74 95 / 29 60 34 31
NATCHEZ 73 91 75 92 / 31 41 21 17
GREENVILLE 73 94 75 95 / 34 41 31 24
GREENWOOD 72 93 75 95 / 40 48 40 32
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
AEG
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1154 AM CDT SUN JUL 21 2013
.AVIATION...
18Z TAFS FOR KOMA...KOFK...KLNK
A SCT TO BKN CU FIELD IS EXPECTED AT OMA/LNK THIS AFTERNOON WITH A
FEW CU AT OFK. THESE WILL LIKELY DISSIPATE QUICKLY THIS EVENING
WITH JUST SOME SCT MID AND HIGH LEVEL CLOUDS EXPECTED OVERNIGHT.
GIVEN THE INCREASE IN LOW-LEVEL MOISTURE WE MAY SEE SOME MVFR CIGS
WITH HZ/BR AT OMA AROUND SUNRISE ON MONDAY BUT IF THIS OCCURS IT
WILL BE SHORT LIVED. SFC CDFNT WILL BE MOVG TOWARD THE TAF SITES
ON MONDAY BUT WON`T MAKE IT PRIOR TO 18Z WITH JUST A GENERAL
SRLY/SWRLY SFC WIND EXPECTED THRU THE PERIOD.
&&
.PREV DISCUSSION... /ISSUED 1019 AM CDT SUN JUL 21 2013/
UPDATE...
UPDATED TO ADJUST MORNING AND AFTERNOON POPS
DISCUSSION...
12Z UPPER AIR ANALYSIS INDICATED THAT A SEASONABLY STRONG
SHORTWAVE TROUGH EXTNDD FM WRN MN INTO CNTRL NEB. THIS WAS
SPREADING LARGE-SCALE ASCENT ACROSS THE FA THIS MORNING. THE 12Z
KOAX RAOB INDCD AROUND 1400 J/KG OF MUCAPE WITH LITTLE CAPPING.
THUS THE COMBINATION OF THE FORCING AND WEAKLY CAPPED ATMOSPHERE
WAS LEADING TO SCT TSRA OVER FAR SE NEB AND SW IA. THIS SHOULD
CONT TO SHIFT EWD THIS MORNING ASSOCIATED WITH THE SHORTWAVE
TROUGH. WHAT HAPPENS IN THE WAKE OF THIS MORNING ACTIVITY IS A BIT
UNCLEAR. MODIFYING THE 12Z SOUNDING YIELDS LITTLE CAPPING AS
TEMPERATURES CLIMB INTO THE MID 80S WITH AROUND 2000 J/KG OF
MLCAPE. THE NEGATIVE THOUGH IS THE SUBSIDENCE THAT WILL BE SPREADING
INTO THE AREA LATER THIS MORNING IN THE WAKE OF THE MORNING
SHORTWAVE TROUGH. THIS IS LIKELY TO COMBINE WITH A LACK OF A SFC
BOUNDARY TO FOCUS CONVERGENCE TO MAKE REDEVELOPMENT THIS AFTERNOON
PRETTY UNLIKELY. WILL MAINTAIN A SCHC OF AFTERNOON STORMS OVER
THE ERN FA OTHERWISE WE FEEL IT WILL BE A PRETTY DRY AFTERNOON.
THE OTHER ELEMENTS OF THE FORECAST APPEAR ON TRACK ATTM.
PREV DISCUSSION... /ISSUED 301 AM CDT SUN JUL 21 2013/
DISCUSSION...
FORECASTING AREAL EXTENT OF CONVECTION THROUGH THE
FORECAST WILL BE A SIGNIFICANT CHALLENGE AS THE REGION REMAINS IN
NORTHWEST FLOW THIS WEEK.
FIRST ROUND OF CONVECTION IS MOVING INTO EASTERN NEBRASKA EARLY
THIS MORNING...BUT WILL ALSO HAVE TO OVERCOME A POCKET OF DRY AIR
AT H85. CONTINUED THETAE ADVECTION SHOULD HELP TO ERODE THIS DRY
POCKET AND CONTINUE TRIGGER STORMS THIS MORNING THAT WILL
CONTINUE TO MOVE EASTWARD THROUGH THE AREA INTO WESTERN IOWA
BEFORE DISSIPATING THROUGH MID TO LATE MORNING. WHILE HEAVY RAINS
ARE NOT WIDESPREAD...SOME VERY SPOTTY LOCATIONS WHERE LIGHTNING IS
OCCURRING ARE LIKELY PICKING UP SOME DECENT MEANINGFUL RAINFALL.
MEANWHILE...WATER VAPOR IMAGERY INDICATES ANOTHER SUBTLE WAVE IS
LIKELY MOVING THROUGH WESTERN SOUTH DAKOTA. ANOTHER CLUSTER OF
STORMS HAS REFIRED ACROSS THAT AREA...MOVING INTO NORTH CENTRAL
NEBRASKA. BOTH THE NAM AND RAP SEEM TO HAVE PICKED UP ON THIS
FEATURE AND MOVE IT THROUGH THE FORECAST AREA THIS AFTERNOON...WHICH
COULD BE THE TRIGGER FOR ADDITIONAL STORMS AS WE HEAD THROUGH PEAK
HEATING. FORWARD SPEED SUGGESTS THAT THIS MAY MOSTLY BE OUT OF THE
AREA BY EARLY THIS EVENING.
THE REMAINDER OF SUNDAY NIGHT AND MONDAY MORNING SHOULD BE DRY. A
FRONTAL BOUNDARY MOVING INTO THE REGION COULD TRIGGER ISOLATED
AFTERNOON STORMS IN NORTHEAST NEBRASKA. TEMPS AHEAD OF THE FRONT
WILL PROBABLY REACH THE LOWER 90S ONCE AGAIN. SHOULD ALSO SEE A
CHANCE OF THUNDERSTORMS MONDAY NIGHT AS THE FRONT MOVES THROUGH
THE AREA.
THE NEXT WAVE APPEARS ON THE HORIZON BY TUESDAY AFTERNOON THEN
MOVES THROUGH THE REGION TUESDAY NIGHT. WEDNESDAY AND WEDNESDAY
NIGHT SHOULD BE DRY...BUT ANOTHER WAVE MOVES INTO THE AREA ON
THURSDAY AND LINGERS THROUGH FRIDAY. THE GFS SUGGESTS THAT WE
MIGHT REMAIN DRY ON SATURDAY...BUT THE ECMWF HAS YET ANOTHER SURGE
OF MOISTURE MOVING THROUGH. NEVERTHELESS...CONFIDENCE DECREASES IN
SPECIFICS TOWARD THE END OF THE WEEK.
DEWALD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS RALEIGH NC
310 PM EDT SUN JUL 21 2013
.SYNOPSIS...
A SURFACE TROUGH WILL PERSIST OVER THE REGION...IN A MOIST AIR
MASS...AT LEAST THROUGH THE MIDDLE OF THE WEEK...AS A TROUGH IN THE
UPPER LEVELS OF THE ATMOSPHERE MOVES INTO THE MID ATLANTIC AND THE
CAROLINAS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 310 PM SUNDAY...
THE LATEST SURFACE ANALYSIS CONTINUED TO SHOW THE SURFACE TROUGH
OVER THE NORTHWEST PIEDMONT TOWARD THE UPSTATE OF SOUTH CAROLINA...
AND ALONG THIS TROUGH WHERE BETTER SURFACE CONVERGENCE
EXISTED...SCATTERED SHOWERS AND THUNDERSTORMS WERE OCCURRING OR
DEVELOPING. DOWNDRAFT CAPE AND LOW-LEVEL SHEAR REMAINED LIMITED...
BUT THE LATEST SPC MESOANALYSIS SHOWED MIXED-LAYER CAPE AROUND
2000J/KG NEAR THE SURFACE TROUGH. SCATTERED SHOWERS AND
THUNDERSTORMS SHOULD CONTINUE TO MOVE INTO THE WESTERN PIEDMONT
DURING THE LATE AFTERNOON...AND THE HRRR WRF HAS BEEN CONSISTENT
SHOWING SCATTERED SHOWERS AND THUNDERSTORMS SPREADING EAST TO ABOUT
U.S. 1 THROUGH 01Z BEFORE GENERALLY DIMINISHING. THROUGHOUT THE
DAY...THE RUC HAS BEEN PERSISTENT MAINTAINING SOME CHANCES FOR
SHOWERS ACROSS THE SANDHILLS AND CENTRAL AND SOUTHERN COASTAL
PLAIN...WHERE THE GFS HAS SLIGHTLY GREATER 850MB LIFT OVERNIGHT AND
WHERE THAT MODEL ALSO FORECASTS A RELATIVE MAXIMUM OF POTENTIAL
VORTICITY MOVING ACROSS THE AREA. GIVEN THIS...IT IS POSSIBLE THAT
SOME OF THE SHOWERS OVER WESTERN NORTH CAROLINA OR THE UPSTATE OF
SOUTH CAROLINA WILL PERSIST AS THEY DRIFT EAST NEAR AND JUST NORTH
OF THE SOUTH CAROLINA BORDER OVERNIGHT. WILL KEEP A SLIGHT CHANCE OF
SHOWERS FOR THE OVERNIGHT HOURS AFTER MIDNIGHT MAINLY EAST OF A LINE
FROM ABOUT KRWI TO KFAY. UNDER A PARTLY-TO-MOSTLY CLOUDY SKY...WITH
AREAS OF CLOUDS COURTESY OF DEEP CONVECTION AND THEN SOME HIGH
CLOUDS MOVING IN FROM THE WEST LATE...OVERNIGHT LOWS WILL AGAIN BE
70 TO 75 DEGREES. THE SREF SHOWS THE POTENTIAL FOR LOW CLOUDS TO BE
LESS THAN THE LAST COUPLE OF MORNINGS...HOWEVER...SOME OF THE
GUIDANCE MAINTAINS THE CHANCES FOR LOW CLOUDS PARTICULARLY TOWARD
KRDU...KFAY...AND KRWI...LESS TOWARD THE TRIAD. IF LOW CLOUDS INDEED
OCCUR...IT IS CURRENTLY THOUGHT THEY SHOULD BE LESS WIDESPREAD THAN
WHAT HAS OCCURRED THIS WEEKEND.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
AS OF 310 PM SUNDAY...
MONDAY AND MONDAY NIGHT...
BOTH THE NAM AND THE GFS GRADUALLY MOVE THE WEAK UPPER LOW OVER THE
SOUTHERN MISSISSIPPI RIVER SLOWLY NORTHEAST...AND INDEED THE LATEST
WATER VAPOR IMAGERY SHOWS THIS WEAK LOW MOVING MORE INTO
MISSISSIPPI. BY THE TIME THE UPPER LOW GETS TO CENTRAL NORTH
CAROLINA...IT IS FORECAST TO WEAKEN FURTHER...AND FORECAST
PARAMETERS OF INSTABILITY...SHEAR...AND MOISTURE ARE SIMILAR TO WHAT
HAS RECENTLY OCCURRED. 850MB THETA-E IS PERSISTENT AROUND 340K AS
WELL...CURRENTLY SUGGESTIVE OF LITTLE OVERALL CHANGE IN ANTICIPATED
CONDITIONS. WITH THE WEAK UPPER LOW THE GFS DOES FORECAST A VERY
MODEST 35KT JETLET INTO CENTRAL NORTH CAROLINA AT 300MB MONDAY
AFTERNOON...BUT WITH MIXED-LAYER CAPE FROM ABOUT 1000J/KG TO
2000J/KG AND DOWNDRAFT CAPE REMAINING 500J/KG OR LESS...THINK
CONDITIONS WILL BE SIMILAR TO THE LAST COUPLE OF DAYS...MOSTLY
SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS...HIGHER
CHANCES RELATIVE TO THE REST OF CENTRAL NORTH CAROLINA TOWARD THE
WESTERN PIEDMONT AS THE WEAK LOW OR ITS REMNANTS APPROACHES...AND A
PARTLY SUNNY DAY ON AVERAGE WITH HIGHS AROUND 90. MONDAY
NIGHT...BOTH THE NAM AND THE GFS FORECAST ALMOST A WEAK PSEUDO FRONT
OR STRONG TROUGH MOVING INTO THE WESTERN PART OF CENTRAL NORTH
CAROLINA WITH DIMINISHING PRECIPITABLE WATER VALUES BEHIND IT TO
NEAR 1.5 INCHES LATE TOWARD THE YADKIN RIVER AND DEW POINTS FALLING
INTO THE UPPER 60S. BUFR SOUNDINGS BECOME SOMEWHAT MORE STABLE
OVERNIGHT IN CENTRAL NORTH CAROLINA...AND QPF IS CERTAINLY
LIMITED...BUT WITH THE APPROACH OF THIS TROUGH WILL MAINTAIN A
SLIGHT CHANCE OF A SHOWER THROUGH THE OVERNIGHT HOURS. OVERNIGHT
LOWS ABOUT A DEGREE OR TWO COOLER THAN WHAT SHOULD OCCUR
TONIGHT...BUT STILL 70 TO 75...MAYBE AN UPPER 60S LOW OR TWO TOWARD
THE FAR WESTERN PIEDMONT. -DJF
TUESDAY THROUGH WEDNESDAY NIGHT...
HEIGHTS WILL CONTINUE TO SLOWLY FALL ALOFT TUESDAY AND WEDNESDAY AS
A BROAD TROUGH BECOMES ESTABLISHED OVER THE EASTERN US.
MEANWHILE...A COLD FRONT TO OUR NORTH WILL SLOWLY SINK SOUTHEAST AND
EVENTUALLY MERGE WITH RELATIVELY STRONG LARGE SCALE LOW LEVEL TROUGH
EAST OF THE MOUNTAINS. ENERGY CURRENTLY MOVING OUT OF
MONTANA/WYOMING IS FORECAST MOVE THROUGH THE BASE OF THE UPPER
TROUGH TUESDAY...FOLLOWED BY ANOTHER SHORTWAVE ON WEDNESDAY.
HOWEVER...THE TIMING AND STRENGTH OF THESE WEAK WAVES AND OTHER
DISTURBANCES WITHIN THE FLOW ARE STILL NEBULOUS. FORECAST SOUNDINGS
DO INDICATE A BIT MORE WESTERLY FLOW ON TUESDAY...WITH PW
TEMPORARILY DROPPING TO 1.5" OR LESS OVER THE WESTERN CWA AND THE
INTRUSION OF DRIER MID LEVEL AIR. HOWEVER...WITH THE MEAN TROUGH
AXIS STILL WEST OF OUR AREA... PROFILES MOISTEN BACK UP ON WEDNESDAY
WITH MORE ENERGY APPROACHING FROM THE WEST. UNDER CYCLONIC FLOW
ALOFT AND MODERATE INSTABILITY...WE SHOULD SEE SCATTERED STORMS
BOTH DAYS BUT BETTER COVERAGE OVER THE EAST IN THE VICINITY OF
BETTER LOW LEVEL CONVERGENCE AND DEEP MOISTURE. HIGHS 88-92. LOWS IN
UPPER 60S AND LOWER 70S. -BLS
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 310 PM SUNDAY...
THE LAST IN A SERIES OF UPPER DISTURBANCES IS FORECAST TO PASS
THROUGH THE UPPER TROUGH ON THURSDAY...WITH MODELS HAVING TRENDED
DRIER FRIDAY AND SATURDAY AS THE REMNANT FRONTAL ZONE OVER THE EAST
COAST STATES SLIDES LITTLE FURTHER EAST TOWARD THE COAST. THERE
SHOULD BE LESS COVERAGE IF STORMS THURSDAY AS THE MID LEVELS BEGIN
TO DRY OUT...BUT THE PASSAGE OF THE MEAN TROUGH AXIS AND SLIGHTLY
STRONGER MID-LEVEL FLOW MAY STILL SUPPORT SOME STRONG TO SEVERE
STORMS. LOWER DEWPOINTS BEHIND THE FRONT/TROUGH SHOULD LIMIT
CONVECTION FRIDAY AND SATURDAY...PARTICULARLY IN THE WEST.
THICKNESSES FALL AS WELL...WITH HIGHS LIKELY TO BE MORE IN THE MID
AND UPPER 80S.
THE BROAD EASTERN US TROUGH IS EXPECTED TO RELOAD BY THE END OF THE
WEEKEND AS ENERGY CONTINUES TO ROTATE AROUND AN UPPER LOW NORTH OF
THE HUDSON BAY. BOTH THE ECMWF AND GFS SHOW A MODEST LOW PRESSURE
SYSTEM MOVING OFF THE FRONT RANGE SATURDAY AND MOVING TOWARD THE
MID-ATLANTIC STATES BY SUNDAY/MONDAY...THOUGH WPC/S EXTENDED
DISCUSSION RAISES SOME DOUBT IN THE STRENGTH OF SUCH A FEATURE.
NONETHELESS...THERE IS ENOUGH AGREEMENT IN THE MODELS TO HAVE MEDIUM
CONFIDENCE IN TEMPS SLIGHTLY BELOW NORMAL OVER THE WEEKEND AND
ANOTHER CHANCE OF STORMS BY THE END OF THE WEEKEND.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 145 PM SUNDAY...
PERSISTENCE CONTINUES OVERALL THROUGH THE 18Z VALID TAF PERIOD.
SHOWERS AND THUNDERSTORMS MOSTLY IN A SCATTERED NATURE WILL OCCUR
WITH THE BETTER CHANCES EARLY IN THE TAF PERIOD TOWARD KGSO AND
KINT. OVERNIGHT...MODELS SHOW LIFT IS BETTER TOWARD THE SANDHILLS
AND SOUTHERN COASTAL PLAIN WHICH MAY KEEP A FEW SHOWERS GOING
PRIMARILY TOWARD KFAY AND JUST SOUTH OF KRWI. GUIDANCE OVERALL SHOWS
THE PROBABILITY OF LATE NIGHT AND EARLY MONDAY MORNING LOW CLOUDS TO
BE LESS THAN SATURDAY AND THIS SUNDAY MORNING. HOWEVER...INCLUDED
LOW CLOUDS FROM ABOUT 10Z TO 14Z AT KRDU...KFAY...AND KRWI WHERE THE
CHANCES RELATIVE TO THE TRIAD TAFS ARE GREATER. IT IS POSSIBLE THAT
ANY LOW CLOUDS THAT DEVELOP LATE TONIGHT ARE MORE SPOTTY IN COVERAGE
AS OPPOSED TO THE MORE WIDESPREAD COVERAGE THAT HAS OCCURRED OVER
THE WEEKEND.
BEYOND THE 18Z VALID TAF PERIOD...AVIATION INTERESTS SHOULD CONTINUE
TO BE PREPARED FOR GENERALLY SCATTERED AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS...AND THEIR ASSOCIATED SUB-VFR CONDITIONS. CHANCES
OF THESE SHOWERS AND THUNDERSTORMS MAY SHIFT FROM BEING GREATER
TOWARD THE TRIAD TAFS MONDAY TO BEING GREATER EAST FOR THE MIDDLE
AND END OF THE WEEK. BASED ON THE LATEST FORECAST GUIDANCE...THE
NEXT DAY WITH THE POTENTIAL FOR MORE WIDESPREAD LOW CLOUDS IN THE
EARLY MORNING HOURS IS THURSDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...DJF
SHORT TERM...DJF/BLS
LONG TERM...BLS
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
146 PM EDT SUN JUL 21 2013
.SYNOPSIS...
A SURFACE TROUGH WILL PERSIST OVER THE REGION...IN A MOIST AIR
MASS...AT LEAST THROUGH THE MIDDLE OF THE WEEK...AS A TROUGH IN THE
UPPER LEVELS OF THE ATMOSPHERE MOVES INTO THE MID ATLANTIC AND THE
CAROLINAS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1035 AM SUNDAY...
THE LATEST SURFACE ANALYSIS CONTINUED TO SHOW A WEAK GRADIENT OVER
CENTRAL NORTH CAROLINA...WITH A PERSISTENT SURFACE TROUGH WEST OF
THE YADKIN RIVER. THE MORNING UPPER-LEVEL ANALYSES SHOWED A FAIRLY
PRONOUNCED 850MB TROUGH OVER CENTRAL NORTH CAROLINA...CAPTURED BY
THE RUC AND FORECAST TO LINGER OVER THE AREA WHILE WEAKENING THROUGH
THE AFTERNOON. ON WATER VAPOR...IT SEEMED AS IF CENTRAL NORTH
CAROLINA WAS IN ALMOST SUBTLE RIDGING BETWEEN A WEAK UPPER LOW OVER
THE SOUTHERN MISSISSIPPI RIVER AND A WEAK WAVE MOVING EAST ACROSS
THE STATE.
IT WAS INTERESTING TO NOTE THAT THE PRECIPITABLE WATER VALUE ON THE
KRNK SOUNDING WAS BELOW 1.4 INCHES THIS MORNING. IT WAS HIGHER AT
KGSO COMPARED TO 12Z SATURDAY. DOWNDRAFT CAPE ON THE SPC
MESOANALYSIS WAS WEAKER THAN SATURDAY...AND OTHER PARAMETERS SUCH AS
THE MID-LEVEL LAPSE RATES AND THETA-E DIFFERENCE ALOFT WERE SLIGHTLY
LESS AS WELL. THE LATEST RUC FORECASTS NOTICEABLE 850MB SUBSIDENCE
OVER CENTRAL NORTH CAROLINA FOR THE AFTERNOON...WITH SOMEWHAT BETTER
LIFT MOVING IN OVER THE NORTHWEST PIEDMONT AND THE SANDHILLS LATE
TODAY AND THIS EVENING.
MOST OF THE CONVECTIVE-ALLOWING MODELS DEVELOP SCATTERED SHOWERS AND
THUNDERSTORMS OVER CENTRAL NORTH CAROLINA THIS AFTERNOON...AND FOR
THE MID-MORNING UPDATE OPTED TO CONCENTRATE THE BETTER CHANCES OVER
THE NORTHWEST PIEDMONT...NEAR WHAT MAY END UP BEING SOME
DIFFERENTIAL HEATING BASED ON THE LATEST VISIBLE IMAGES. A STORM OR
TWO COULD BECOME STRONG...BUT THE PREPONDERANCE OF THE CURRENT
EVIDENCE SUGGESTS THE POTENTIAL FOR A SEVERE STORM IS LIMITED. WILL
REVIEW LATER DATA TO TRY TO FOCUS BETTER CHANCES FOR THIS EVENING...
AS BASED ON THE LATEST RUC THIS WOULD BE MAINLY NORTH OF U.S. 64 AND
OVER THE SANDHILLS WHERE THE GREATER 850MB LIFT IS CONCENTRATED.
KEPT HIGH TEMPERATURES AS IS GIVEN AT LEAST SOME EXPECTED SUN...
THOUGH HIGHS ARE FORECAST BELOW FULL SUN 1000-850MB THICKNESS VALUES
WHICH WOULD SUGGEST HIGHS A CATEGORY WARMER. LOWS TONIGHT IN THE
LOWER 70S.
&&
.SHORT TERM /MONDAY AND MONDAY NIGHT/...
AS OF 300 AM SUNDAY...
WEAK SHORT-WAVE ENERGY CURRENTLY OVER THE NORTHERN PLAINS WILL
UNDERGO SLIGHT AMPLIFICATION(ALONG WITH AMPLIFICATION OF THE LONG
WAVE TROUGH AS WELL)AS IT PROGRESSES EAST-SOUTHEASTWARD INTO THE
OHIO AND TN VALLEY ON MONDAY...REACHING THE CENTRAL-SOUTHERN BY
DAYBREAK TUESDAY. IN RESPONSE TO THE ATTENDANT UPSTREAM HEIGHT FALLS
ON THE ORDER OF 20 TO 30 METERS...A WEAK WAVE OF LOW PRESSURE IS
FORECAST TO DEVELOP ALONG THE SURFACE TROUGH OF LOW PRESSURE
BISECTING THE VIRGINIAS AND CAROLINAS...WHICH WILL SERVE TO
STRENGTHEN THE LOW-LEVEL MOISTURE CONVERGENCE AS A POOL OF +2.0
PWATS RESIDES OVER THE SOUTHEASTERN STATES. ADDITIONALLY...THERE IS
ALSO THE POTENTIAL THAT REMNANT CENTER ASSOCIATED WITH THE WEAK
UPPER LOW CURRENTLY OVER LOUISIANA COULD MOVE NORTHEASTWARD OVER THE
AREA LATE MONDAY AND INTO MONDAY NIGHT...FURTHER AUGMENTING ASCENT
OVER THE AREA. AS SUCH...CONVECTION MONDAY AFTERNOON IS EXPECTED TO
BE MORE ROBUST THAN IN PREVIOUS DAYS...WITH THE THREAT OF CONVECTION
PERSISTING THROUGH THE OVERNIGHT HOURS.
CONFIDENCE IN THE TIMING/IMPACTS OF THIS DISTURBANCE IS LOW AT THIS
POINT...ESPECIALLY WITH THE 00Z/21 GFS COMPLETELY SHEARING THE
DISTURBANCE COMPLETING APART OVER GEORGIA/SC. HOW THIS FEATURES
EVOLVES WILL LIKELY BE THE DIFFERENCE BETWEEN LIKELY OR CHANCE POPS
ACROSS CENTRAL NC MONDAY AFTERNOON/EVENING.
HIGH +2.0 PWATS COULD RESULT IN ONE OR TWO WET MICROBURSTS...MAINLY
DURING PEAK AFTERNOON HEATING/DESTABILIZATION...WITH A MORE
ORGANIZED SEVERE THREAT BEING IMPEDED BY WEAK SHEAR AND WEAK
MID-LEVEL LAPSE RATES. ALSO...WITH LOCAL RIVER....STREAMS AND CREEKS
STILL RUNNING HIGH...FLASH FLOODING WILL ALSO BE POSSIBLE.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 245 AM SUNDAY...
TUESDAY AND TUESDAY NIGHT:
WITH THE PERSISTENT SOUTHWEST FLOW...THE ATMOSPHERE WILL REMAIN
SUFFICIENTLY MOIST AND UNSTABLE. THE SURFACE TROUGH IS EXPECTED TO
STALL OVER THE MID ATLANTIC...WITH THE UPPER LEVEL TROUGH SLOWLY
DRIFTING EAST OVER THE AREA. THE 00Z RUN OF THE GFS PICKS UP ON A H3
DISTURBANCE MOVING THROUGH NC TUESDAY AFT/EVE...WHICH SHOULD HELP
ENHANCE THE DIURNALLY DRIVEN CONVECTION. BEST LIFT WILL TRANSLATE
FROM NW TO SE THROUGH CENTRAL NC AHEAD OF THE BACKDOOR COLD
FRONT...WHICH WPC PREDICTS WILL MOVE TROUGH THE AREA TUESDAY NIGHT
AND INTO WEDNESDAY...POTENTIALLY STALLING ALONG THE COAST. AS
SUCH...WILL SHOW BEST CHANCES FOR CONVECTION FROM THE TRIANGLE SE
BETWEEN 18Z TUESDAY AND 06Z WEDNESDAY. HIGH TEMPS IN THE UPPER 80S
TO LOW 90S AND OVERNIGHT LOWS IN THE LOW TO MID 70S EXPECTED.
WEDNESDAY THROUGH SATURDAY:
LOW LEVEL WINDS MAY TEMPORARILY BECOME MORE WNW BEHIND THE BACKDOOR
FRONT SHOULD IT INDEED MOVE THROUGH THE AREA AND STALL ALONG THE
COAST BY WEDNESDAY...WHICH WOULD YIELD A SUBSEQUENT DRYING OF THE
MID LEVELS. CURRENT MODEL AGREEMENT WITH REGARD TO THE TROUGH...AT
BOTH THE SURFACE AND ALOFT...LINGERING OVER THE AREA THROUGH THE END
OF THE WEEK IS GOOD. THE LOCATION OF THE TROUGH AXIS WILL PLAY A
ROLE IN WHERE THE BEST MOISTURE IS AVAILABLE...WHICH CURRENTLY IS
EXPECTED ALONG THE COAST. DEPENDING ON THEIR TIMING...A SERIES OF
UPPER LEVEL DISTURBANCES MOVING OVER THE AREA COULD ENHANCE DIURNAL
CONVECTIVE ACTIVITY THROUGH THE PERIOD. OF LESSER CERTAINTY IS THE
COVERAGE AND LOCATION OF THE ANTICIPATED AFT/EVE SHOWERS AND STORMS.
FOR NOW WILL CONTINUE TO INDICATE BEST PRECIP CHANCES DURING THE
AFT/EVE HOURS ACROSS THE AREA...WITH SLIGHTLY HIGHER CHANCES ACROSS
THE EAST WHERE THE BEST MOISTURE IS EXPECTED. ONLY SMALL CHANGES IN
TEMPS FROM DAY TO DAY THROUGH THE PERIOD...HIGHS MAINLY IN THE MID
80S TO AROUND 90 DEGREES WITH OVERNIGHT LOWS MAINLY IN THE UPPER 60S
TO LOW 70S.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 145 PM SUNDAY...
PERSISTENCE CONTINUES OVERALL THROUGH THE 18Z VALID TAF PERIOD.
SHOWERS AND THUNDERSTORMS MOSTLY IN A SCATTERED NATURE WILL OCCUR
WITH THE BETTER CHANCES EARLY IN THE TAF PERIOD TOWARD KGSO AND
KINT. OVERNIGHT...MODELS SHOW LIFT IS BETTER TOWARD THE SANDHILLS
AND SOUTHERN COASTAL PLAIN WHICH MAY KEEP A FEW SHOWERS GOING
PRIMARILY TOWARD KFAY AND JUST SOUTH OF KRWI. GUIDANCE OVERALL SHOWS
THE PROBABILITY OF LATE NIGHT AND EARLY MONDAY MORNING LOW CLOUDS TO
BE LESS THAN SATURDAY AND THIS SUNDAY MORNING. HOWEVER...INCLUDED
LOW CLOUDS FROM ABOUT 10Z TO 14Z AT KRDU...KFAY...AND KRWI WHERE THE
CHANCES RELATIVE TO THE TRIAD TAFS ARE GREATER. IT IS POSSIBLE THAT
ANY LOW CLOUDS THAT DEVELOP LATE TONIGHT ARE MORE SPOTTY IN COVERAGE
AS OPPOSED TO THE MORE WIDESPREAD COVERAGE THAT HAS OCCURRED OVER
THE WEEKEND.
BEYOND THE 18Z VALID TAF PERIOD...AVIATION INTERESTS SHOULD CONTINUE
TO BE PREPARED FOR GENERALLY SCATTERED AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS...AND THEIR ASSOCIATED SUB-VFR CONDITIONS. CHANCES
OF THESE SHOWERS AND THUNDERSTORMS MAY SHIFT FROM BEING GREATER
TOWARD THE TRIAD TAFS MONDAY TO BEING GREATER EAST FOR THE MIDDLE
AND END OF THE WEEK. BASED ON THE LATEST FORECAST GUIDANCE...THE
NEXT DAY WITH THE POTENTIAL FOR MORE WIDESPREAD LOW CLOUDS IN THE
EARLY MORNING HOURS IS THURSDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...CBL/DJF
SHORT TERM...CBL
LONG TERM...KMC
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
303 PM CDT SUN JUL 21 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 303 PM CDT SUN JUL 21 2013
MAIN CHALLENGE CONTINUES TO BE TSTM CHANCES AND SEVERITY FOR
TONIGHT. LATEST MODEL GUIDANCE CONTINUES TO SUPPORT A THREAT FOR
PORTIONS OF THE FA BUT EARLY ON MAINLY FOR THE KDVL REGION AS IT
SHOULD TAKE A WHILE TO REACH THE RED RIVER VALLEY.
CURRENTLY HAVE A COLD FRONT WORKING INTO FAR NORTHWEST ND WITH AN
AREA OF LOW PRESSURE THERE AS WELL. A WARM FRONT EXTENDS SE FROM
THIS LOW DOWN TO NEAR KBIS AND KABR. IN THIS WARM SECTOR DEW
POINTS ARE GENERALLY IN THE LOW TO MID 60S WITH TEMPS IN THE 80S.
EAST OF THE WARM FRONT DEW POINTS HAVE BEEN SLOW TO RECOVER FROM
MORNING LOWS WITH 50S STILL COMMON. THERE HAS BEEN A WEAK TSTM
COMPLEX OVER SOUTHWEST MANITOBA RIDING AHEAD OF THE MAIN SHORT
WAVE. THIS SHOULD GET INTO THE FAR NW FA IN THE NEXT HOUR OR SO.
INSTABILITY IS WEAK OUT AHEAD OF THIS INITIAL COMPLEX BUT IT MAY
CONTINUE TO MOVE EAST ALONG THE BORDER WITH THE UPPER JET DYNAMICS
IN PLACE. THE SEVERE THREAT SHOULD BE BEHIND THIS COMPLEX CLOSER
TO THE COLD FRONT AND SFC LOW OVER WESTERN ND. INSTABILITY IS
BETTER HERE WITH THE ABOVE MENTIONED WARMER AND MOIST AIR. THE
MAIN SHORT WAVE ENERGY APPEARS TO BE LOCATED OVER SOUTHERN ALBERTA
WHICH IS NEARING THE SFC BOUNDARY. WITH THE WAVE AND THE UPPER JET
ENERGY A MORE ORGANIZED TSTM COMPLEX IS EXPECTED TO GET UNDERWAY
OUT WEST. SPC HAS ISSUED MCD 1456 AND A NEW TORNADO WATCH FOR
PORTIONS OF WESTERN AND CENTRAL ND. THERE HAVE BEEN A COUPLE OF
CELLS THAT HAVE POPPED UP NEAR KISN THAT MAY BE THE START OF SOME
STRONGER CELLS. NOT EXPECTING ANY STRONG STORMS TO APPROACH OUR
WESTERN FA FOR A FEW MORE HOURS YET SO WE WILL HAVE TIME TO WATCH
AND SEE HOW THINGS DEVELOP. LATEST RAP BRINGS SOME STORMS INTO
OUR WESTERN FA IN THE 01-02Z MON TIME FRAME. NSSL WRF IS A LITTLE
FASTER AND AS MENTIONED IN AN EARLIER AFD UPDATE IT DID BRING
TSTMS A LOT FURTHER SOUTH THAN WHAT IS ANTICIPATED. FOLLOWED MORE
CONTINUITY AND KEPT HIGHER PCPN CHANCES ACROSS THE NORTHERN HALF
OF THE FA TONIGHT WITH LOWER CHANCES ACROSS THE SOUTH. THE
COMBINATION OF THE LOW LEVEL JET UPPER JET AND THE WAVE SHOULD
KEEP SHOWERS AND TSTMS GOING AFTER DARK JUST NOT SURE HOW LONG THE
SEVERE POTENTIAL WILL GO.
LEFT SOME LINGERING LOW PCPN CHANCES ACROSS THE EAST ON MONDAY
MORNING WITH DRYING ACROSS THE WEST. SHOULD BE A FAIRLY NICE DAY
WITH DRIER AIR MOVING BACK IN WITH NORTHWEST WINDS. MON NIGHT WILL
BE A LITTLE COOL AGAIN ESPECIALLY ACROSS THE NORTH.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 303 PM CDT SUN JUL 21 2013
SHOULD REMAIN DRY TUE WITH FAIRLY LIGHT WINDS DUE TO THE PROXIMITY
OF THE SFC HIGH. CHANCES FOR PCPN RETURN BY TUE NIGHT AND WED
ALTHOUGH MODELS NOT IN VERY GOOD AGREEMENT ON THE DETAILS.
WEDNESDAY NIGHT-SUNDAY...12Z MODELS MAINTAIN SIMILAR IDEA AS
PREVIOUS RUNS. NORTHWEST FLOW ALOFT INTO FRIDAY WITH UPPER RIDGING
BUILDING INTO THE REGION FOR THE WEEKEND. THERE WILL BE SLIGHT
THUNDERSTORM CHANCES WITH ANY UPPER WAVE WITHIN THE NORTHWEST FLOW
ALOFT...WITH THESE CHANCES ENDING ONCE THE RIDGING BUILDS INTO THE
REGION. TEMPERATURES NEAR OR SLIGHTLY BELOW NORMAL VALUES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1249 PM CDT SUN JUL 21 2013
THE MAIN CONCERN WILL BE TIMING OF THUNDERSTORMS. LATEST MODEL
GUIDANCE IN LINE WITH PREVIOUS THINKING AND NOT MUCH CHANGE NEEDED
TO PREVIOUS TAFS. ANTICIPATE A LINE OF STORMS TO MOVE INTO NORTHEAST
NORTH DAKOTA AROUND 00Z...AND INTO THE NORTHERN VALLEY AROUND
02Z...CONTINUING TO THE EAST. STILL NOT A LOT OF CONFIDENCE WITH HOW
FAR SOUTH THUNDER CHANCES WILL BE AND LEFT OUT OF THE KFAR FORECAST
(COVERAGE WILL BE SIGNIFICANTLY LESS TO THE SOUTH). SOUTHERLY WINDS
WILL SHIFT TO THE WEST/NORTHWEST TONIGHT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...GODON
LONG TERM...GODON/TG
AVIATION...TG
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1113 AM CDT SUN JUL 21 2013
.UPDATE...
AN UPPER TROF IS BEGINNING TO PUSH INTO THE MIDSOUTH THIS MORNING.
LATEST MODELS INDICATE CHANCES FOR CONVECTION WILL MAINLY COME
FROM DIURNAL BASED STORMS THIS AFTERNOON. ALTHOUGH...A MINOR
SHORTWAVE WILL PUSH INTO NORTHEAST ARKANSAS LATE THIS AFTERNOON
WHICH COULD INCREASE COVERAGE. THE SHORTWAVE PRODUCED CONVECTION
ACROSS SE KANSAS AND NE OKLAHOMA OVERNIGHT. THE COMPLEX HAS SINCE
DIED OVER NW ARKANSAS. THIS IS A LOT QUICKER THAN WHAT THE LATEST HRRR
HAS SHOWN. THERE MAY BE SOME REDEVELOPMENT THIS AFTERNOON THUS
WILL KEEP 50-60 POPS ACROSS NE ARKANSAS OTHERWISE WILL REDUCE
CHANCES ACROSS THE REST OF THE CWA TO 30S.
KRM
&&
.DISCUSSION... /ISSUED 424 AM CDT SUN JUL 21 2013/
A WET WEATHER PATTERN WAS BEGINNING TO TAKE SHAPE ACROSS THE
MIDSOUTH THAT WILL LEAD TO SEVERAL DAYS WITH SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS. BY THURSDAY...MANY LOCATIONS ARE
EXPECTED TO HAVE RECEIVED TWO OR THREE OF RAIN...LOCALLY MORE.
EARLY THIS MORNING...A NEARLY STATIONARY FRONT STRETCHED TO THE
NORTH OF THE MIDSOUTH FROM CENTRAL MO TO SOUTHERN IN. OUTFLOW
BOUNDARIES FORMED IN ASSOCIATION WITH THUNDERSTORMS THAT DEVELOPED
SOUTH OF THIS FRONT WITH THESE BOUNDARIES PUSHING INTO EAST AR AND
NORTHWEST TN LAST EVENING. THIS SPARKED SCATTERED THUNDERSTORMS IN
PORTIONS OF THIS REGION DURING THE NIGHT BUT MOST HAVE NOW
DISSIPATED. A FEW SHOWERS AND THUNDERSTORMS DEVELOPED EARLY THIS
MORNING ACROSS PORTIONS OF NORTHEAST MS DUE TO A WEAK BUT LARGE LOW
PRESSURE SYSTEM ALOFT CENTERED ALONG THE NORTHEAST LA / CENTRAL MS
BORDER.
SEVERAL FACTORS WILL LEAD TO SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS ACROSS THE MIDSOUTH TODAY AND TONIGHT.
AN UPPER LEVEL SHORT WAVE WILL PUSH TOWARD THE MIDSOUTH FROM THE
NORTHWEST WITH UPPER LEVEL HEIGHTS CONTINUING TO DECREASE TO
UNSEASONABLY LOW VALUES ACROSS THE MIDSOUTH. THE UPPER LEVEL LOW TO
OUR SOUTH WILL PUSH EAST NORTHEASTWARD TO JUST SOUTH OF NORTHEAST
MS. A MOIST AND UNSTABLE ATMOSPHERE WILL EXIST ACROSS THE MIDSOUTH.
A FEW STRONG THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON AND TONIGHT
WITH WEAK MID LEVEL LAPSE RATES LIMITING THE THREAT FOR SEVERE
THUNDERSTORMS. WINDS GUSTS TO NEAR 50 MPH...SMALL HAIL...AND HEAVY
RAINFALL WITH LOCALIZED FLASH FLOODING MAY OCCUR. PRECIPITABLE
WATER VALUES WILL INCREASE TO BETWEEN 2 AND 2.25 INCHES ALONG AND
WEST OF THE MS RIVER. UPPER LEVEL HEIGHTS WILL CONTINUE TO LOWER
ACROSS THE MIDSOUTH TONIGHT AS THE SHORT WAVE EMBEDDED IN A BROAD
UPPER LEVEL TROUGH MOVES INTO THE MIDSOUTH RESULTING IN NUMEROUS
SHOWERS AND THUNDERSTORMS.
ON MONDAY...AN LARGE UPPER LEVEL TROUGH WILL DEEPEN OVER THE EASTERN
UNITED STATES. MID LEVEL LAPSE RATES WILL DECREASE ACROSS THE
MIDSOUTH LEADING TO INCREASED INSTABILITY. NUMEROUS SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS THE REGION. THIS WILL
PLAY HAVOC WITH HIGH TEMPERATURES SINCE IT IS DIFFICULT TO DETERMINE
HOW HOT IT WILL GET BEFORE THE SHOWERS AND STORMS DEVELOP.
A GOOD CHANCE OF SHOWERS AND THUNDERSTORMS WILL CONTINUE MONDAY
NIGHT AND TUESDAY AS UPPER LEVEL SHORT WAVES EMBEDDED IN NORTHWEST
FLOW ALOFT CONTINUE TO INTERACT WITH A MOIST AND UNSTABLE
ATMOSPHERE.
FOR TUESDAY NIGHT AND WEDNESDAY...THE STORMY WEATHER PATTERN WILL
CONTINUE ALTHOUGH THE MODELS ARE NOT IN SYNC WITH THE DETAILS. THE
GFS PUSHES A COLD FRONT INTO THE REGION FROM THE NORTH QUICKER THAN
THE ECMWF DOES. HOWEVER...THE MODELS DO AGREE THAT A VERY UNSTABLE
AND MOIST ATMOSPHERE WILL BE LOCATED OVER THE MIDSOUTH INTO
WEDNESDAY.
KEPT THURSDAY RAINFREE AS DRIER AIR PUSHES INTO THE REGION FOLLOWING
THE PASSAGE OF A WEAK COLD FRONT. FRIDAY LOOKS RAINFREE ALSO WITH A
MILD START TO THE DAY BEFORE AFTERNOON TEMPERATURES WARM TO AROUND
THE NORMAL VALUES FOR THIS TIME OF THE YEAR.
LOOKING AT MODEL FORECAST CHARTS FOR FRIDAY NIGHT AND SATURDAY...YOU
WOULD NOT THINK IT WAS JULY. THE MODELS ARE IN FAIRLY GOOD AGREEMENT
FOR THAT FAR OUT. ANOTHER BROAD UNSEASONABLY DEEP UPPER LEVEL TROUGH
WILL DIG ALONG THE EASTERN UNITED STATES. THE GFS INDICATES A 1010
MB LOW NEAR THE MO BOOTHEEL 7 AM SATURDAY WITH A COLD FRONT
TRAILING TO THE SOUTHWEST WHILE THE ECMWF IS A LITTLE SLOWER AND
STRONGER INDICATING A 1006 MB LOW OVER SOUTH CENTRAL MO WITH A
TRAILING COLD FRONT TO THE SOUTHWEST. A CHANCE OF SHOWERS AND
THUNDERSTORMS WILL OCCUR AHEAD OF THIS SYSTEM FRIDAY NIGHT AND
SATURDAY. COOLER AND DRY HIGH PRESSURE IS FORECAST TO BEHIND INTO
THE REGION FROM THE NORTH WITH PASSAGE OF THE LOW PRESSURE SYSTEM
AND COLD FRONT.
JCL
&&
.AVIATION...
12Z TAFS
PRIMARY FORECAST CONCERN REMAINS TIMING AND LOCATION OF TSRA
ONSET. TSRA CHANCES WILL INCREASE AT ALL LOCATIONS AFTER 15Z.
PRESENCE OF ISOLATED SHRA/TSRA EARLY THIS MORNING INDICATES SOME
ELEVATED INSTABILITY...BUT THIS ACTIVITY HAS FAILED TO ORGANIZE
FOR ANY APPRECIABLE LENGTH OF TIME.
FOR THE 12Z TAFS...HAVE NARROWED TEMPOS DOWN TO NEAR PEAK HEATING
WITH RESPECT TO TSRA TIMING. OF CONCERN IS UPPER LEVEL LOW OVER
NORTHEAST LA...WHICH COULD HELP INITIATE TSRA BY LATE MORNING. GFS
LAMP GUIDANCE AND HRRR MODELS SHOWED LITTLE EFFECT OF THIS UPPER
LEVEL FEATURE FOR THE MORNING HOURS. BUT WILL SKIES TO START THE
DAY... AMPLE SURFACE HEATING OVER THE ARKLAMISS MAY TOUCH OFF
MID/LATE MORNING TSRA POSSIBLY EXTENDING UP TOWARD MEM.
PWB
&&
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 93 74 91 75 / 30 60 60 50
MKL 89 71 89 72 / 30 60 60 50
JBR 91 72 91 73 / 50 60 60 50
TUP 92 73 90 73 / 30 60 60 50
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
532 PM CDT SUN JUL 21 2013
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 330 PM CDT SUN JUL 21 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A COUPLE
SHORTWAVES UPSTREAM...ONE OVER WESTERN WISCONSIN WHICH IS
RESPONSIBLE FOR THE CLUSTER OF SHOWERS AND STORMS MOVING OVER
CENTRAL WISCONSIN...AND ANOTHER OVER IOWA. MAINLY THE SOUTHERN
PORTION OF THE FORECAST AREA WILL BE IMPACTED WITH THESE STORMS FOR
THE REST OF THE AFTERNOON...BUT NO SEVERE WEATHER IS EXPECTED.
FURTHER UPSTREAM...THE NEXT SHORTWAVE IS PRODUCING STORMS OVER FAR
SOUTH-CENTRAL CANADA AND NORTHERN NORTH DAKOTA WHICH WILL ARRIVE
TOMORROW. PRECIP CHANCES FOR THE REST OF TODAY AND SEVERE WEATHER
CHANCES TOMORROW ARE THE MAIN FORECAST CONCERNS.
TONIGHT...SHORTWAVE IMPULSES MOVING EAST ACROSS THE REGION WILL TAKE UNTIL
MID TO LATE EVENING TO EXIT. AS A RESULT...POTENTIAL WILL BE THERE
FOR ISOLATED TO SCATTERED THUNDERSTORMS UNTIL THEN OVER THE SOUTHERN
FORECAST AREA...EVEN THOUGH THE MAIN CLUSTER WILL HAVE PROBABLY
EXITED BY THE START OF THE EVENING. PLENTY OF CLEARING OCCURRING
UPSTREAM OF THE SHORTWAVES...THOUGH MODELS DEPICT WEAK ISENTROPIC
ASCENT CONTINUING THROUGH THE NIGHT. AM THINKING WILL SEE A PERIOD
OF SUBSIDENCE BEHIND THE WAVE...WHICH COULD LEAD TO A SEVERAL HOURS
OF MOSTLY CLEAR TO PARTLY CLOUDY CONDITIONS. NOT SURE HOW LONG THIS
WILL LAST...BUT 850MB THETAE ADVECTION DOES RAMP UP LATE AHEAD OF
THE SHORTWAVE CURRENTLY MOVING INTO NORTHERN NORTH DAKOTA. NOT OUT
OF THE QUESTION THAT CONVECTION COULD APPROACH N-C WISCONSIN LATE
TONIGHT. SO WILL SHOW INCREASING CLOUDS AFTER MIDNIGHT ALONG WITH
SLIGHT CHANCE TO CHANCE POPS OVER CENTRAL AND NORTH-CENTRAL
WISCONSIN. LOWS MAINLY IN THE MID 50S TO LOW 60S.
MONDAY...THE NORTH DAKOTA SHORTWAVE WILL MOVE ACROSS NORTHERN
WISCONSIN DURING THE MORNING. BOTH THE NAM AND GFS SHOW A DECENT
WIND SHIFT OCCURRING AT 700MB SO WOULD NOT BE SURPRISED TO SEE SOME
CONVECTION MOVE ACROSS THE NORTH. THEN A STRONG SHORTWAVE OVER
WESTERN ONTARIO WILL DRIVE A COLD FRONT ACROSS NORTHWEST WISCONSIN
DURING THE AFTERNOON. DEPENDING UPON IF PRECIP OCCURS OVER NORTHERN
WISCONSIN AND HOW MUCH DESTABILIZATION CAN OCCUR WITH AMPLE CLOUD
COVER...MODIFYING PROGGED SOUNDINGS NEAR RHINELANDER FOR AN 80F/64F
PARCEL YIELDS 1700 J/KG OF ML CAPE AT 21Z. WITH 0-6KM BULK SHEAR
VALUES OF 30-35KTS...POTENTIAL WILL BE THERE FOR SEVERE STORMS
TOMORROW AFTERNOON OVER N-C AND POSSIBLY CENTRAL WISCONSIN TOO. WARM
ADVECTION AHEAD OF THE FRONT WILL PUSH HIGHS TO THE UPPER 70S AND MID
80S.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 330 PM CDT SUN JUL 21 2013
NOT MUCH CHANGE IN THE OVERALL FORECAST FOR THIS PERIOD AS
SHORTWAVE TROFS MOVE THROUGH MEAN TROF POSITION ACROSS GREAT
LAKES. LATEST GFS AND ECMWF IN GENERAL AGREEMENT THROUGH MOST OF
PERIOD ON STRENGTH AND TIMING OF SYSTEMS.
TEMPS WILL BE AOB NORMAL FOR MUCH OF WEEK...AFTER MONDAY. IN
FACT...HIGHS NEXT WEEKEND MAY STRUGGLE TO REACH 70 ACROSS PARTS OF
THE NORTH AS NW FLOW IS REINFORCED BEHIND LATE WEEK SYSTEM.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 516 PM CDT SUN JUL 21 2013
AREAS OF MVFR CIGS WILL SPREAD INTO CENTRAL AND NORTH CENTRAL
WISCONSIN THROUGH THIS EVENING AND POSSIBLY OVER EAST CENTRAL
WISCONSIN OVERNIGHT AS A SHORT WAVE TRACKS SOUTHEAST OF SOUTHEAST
WISCONSIN. RETURN FLOW DEVELOPS OVERNIGHT WHICH COULD LEAD TO MORE
MVFR CIGS OVER THE REGION. IF THESE MVFR CIGS BECOME MORE WIDESPREAD
OVERNIGHT...MAY LINGER INTO MONDAY MORNING UNTIL MIXING LIFTS
CIGS TO VFR LEVELS AHEAD OF AN APPROACHING COLD FRONT. SCATTERED MVFR
CIGS AND VSBYS DUE TO SHOWERS AND STORMS LIKELY ALONG THIS FRONT
STARTING MONDAY AFTERNOON OVER NORTHWEST WISCONSIN BEFORE REACHING
SOUTHEAST WISCONSIN MONDAY NIGHT.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......JKL
AVIATION.......TDH
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 330 PM CDT SUN JUL 21 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A COUPLE
SHORTWAVES UPSTREAM...ONE OVER WESTERN WISCONSIN WHICH IS
RESPONSIBLE FOR THE CLUSTER OF SHOWERS AND STORMS MOVING OVER
CENTRAL WISCONSIN...AND ANOTHER OVER IOWA. MAINLY THE SOUTHERN
PORTION OF THE FORECAST AREA WILL BE IMPACTED WITH THESE STORMS FOR
THE REST OF THE AFTERNOON...BUT NO SEVERE WEATHER IS EXPECTED.
FURTHER UPSTREAM...THE NEXT SHORTWAVE IS PRODUCING STORMS OVER FAR
SOUTH-CENTRAL CANADA AND NORTHERN NORTH DAKOTA WHICH WILL ARRIVE
TOMORROW. PRECIP CHANCES FOR THE REST OF TODAY AND SEVERE WEATHER
CHANCES TOMORROW ARE THE MAIN FORECAST CONCERNS.
TONIGHT...SHORTWAVE IMPULSES MOVING EAST ACROSS THE REGION WILL TAKE UNTIL
MID TO LATE EVENING TO EXIT. AS A RESULT...POTENTIAL WILL BE THERE
FOR ISOLATED TO SCATTERED THUNDERSTORMS UNTIL THEN OVER THE SOUTHERN
FORECAST AREA...EVEN THOUGH THE MAIN CLUSTER WILL HAVE PROBABLY
EXITED BY THE START OF THE EVENING. PLENTY OF CLEARING OCCURRING
UPSTREAM OF THE SHORTWAVES...THOUGH MODELS DEPICT WEAK ISENTROPIC
ASCENT CONTINUING THROUGH THE NIGHT. AM THINKING WILL SEE A PERIOD
OF SUBSIDENCE BEHIND THE WAVE...WHICH COULD LEAD TO A SEVERAL HOURS
OF MOSTLY CLEAR TO PARTLY CLOUDY CONDITIONS. NOT SURE HOW LONG THIS
WILL LAST...BUT 850MB THETAE ADVECTION DOES RAMP UP LATE AHEAD OF
THE SHORTWAVE CURRENTLY MOVING INTO NORTHERN NORTH DAKOTA. NOT OUT
OF THE QUESTION THAT CONVECTION COULD APPROACH N-C WISCONSIN LATE
TONIGHT. SO WILL SHOW INCREASING CLOUDS AFTER MIDNIGHT ALONG WITH
SLIGHT CHANCE TO CHANCE POPS OVER CENTRAL AND NORTH-CENTRAL
WISCONSIN. LOWS MAINLY IN THE MID 50S TO LOW 60S.
MONDAY...THE NORTH DAKOTA SHORTWAVE WILL MOVE ACROSS NORTHERN
WISCONSIN DURING THE MORNING. BOTH THE NAM AND GFS SHOW A DECENT
WIND SHIFT OCCURRING AT 700MB SO WOULD NOT BE SURPRISED TO SEE SOME
CONVECTION MOVE ACROSS THE NORTH. THEN A STRONG SHORTWAVE OVER
WESTERN ONTARIO WILL DRIVE A COLD FRONT ACROSS NORTHWEST WISCONSIN
DURING THE AFTERNOON. DEPENDING UPON IF PRECIP OCCURS OVER NORTHERN
WISCONSIN AND HOW MUCH DESTABILIZATION CAN OCCUR WITH AMPLE CLOUD
COVER...MODIFYING PROGGED SOUNDINGS NEAR RHINELANDER FOR AN 80F/64F
PARCEL YIELDS 1700 J/KG OF ML CAPE AT 21Z. WITH 0-6KM BULK SHEAR
VALUES OF 30-35KTS...POTENTIAL WILL BE THERE FOR SEVERE STORMS
TOMORROW AFTERNOON OVER N-C AND POSSIBLY CENTRAL WISCONSIN TOO. WARM
ADVECTION AHEAD OF THE FRONT WILL PUSH HIGHS TO THE UPPER 70S AND MID
80S.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 330 PM CDT SUN JUL 21 2013
NOT MUCH CHANGE IN THE OVERALL FORECAST FOR THIS PERIOD AS
SHORTWAVE TROFS MOVE THROUGH MEAN TROF POSITION ACROSS GREAT
LAKES. LATEST GFS AND ECMWF IN GENERAL AGREEMENT THROUGH MOST OF
PERIOD ON STRENGTH AND TIMING OF SYSTEMS.
TEMPS WILL BE AOB NORMAL FOR MUCH OF WEEK...AFTER MONDAY. IN
FACT...HIGHS NEXT WEEKEND MAY STRUGGLE TO REACH 70 ACROSS PARTS OF
THE NORTH AS NW FLOW IS REINFORCED BEHIND LATE WEEK SYSTEM.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1223 PM CDT SUN JUL 21 2013
A SHOWER AND THUNDERSTORM COMPLEX WILL MARCH EAST ACROSS
CENTRAL AND EAST-CENTRAL WISCONSIN THIS AFTERNOON. VSBYS AND CIGS
TO FALL TO MVFR LEVELS WITHIN THE THUNDERSTORMS...BUT STRONG GUSTY
WINDS OR LARGE HAIL WILL NOT OCCUR. BEHIND THE THUNDERSTORM
COMPLEX...SATELLITE IMAGES SHOW MOSTLY CLEAR CONDITIONS UNTIL YOU
REACH NORTH DAKOTA. AS A RESULT...THINK WILL SEE A PERIOD OF MOSTLY
CLEAR TO SCT SKY CONDITIONS AFTER THE THUNDERSTORMS DEPART...UNTIL
CLOUDS INCREASE LATE TONIGHT. THE DISTURBANCE JUST NORTH OF NORTH
DAKOTA COULD BRING THUNDER TO NORTH-CENTRAL WISCONSIN TOMORROW
MORNING...BUT CONFIDENCE IS NOT THERE TO INCLUDE IN THE TAFS AT THIS
TIME.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......JKL
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
105 PM CDT SUN JUL 21 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 300 AM CDT SUN JUL 21 2013
CURRENTLY AS OF 08Z...
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS LOOKED VERY SIMILAR
TO THIS TIME YESTERDAY...CONSISTING OF NORTHWEST FLOW FROM BRITISH
COLUMBIA INTO THE GREAT LAKES REGION...NUMEROUS SHORTWAVES RIDING
THROUGH THE FLOW...AND TROUGHING OVER SOUTHEAST CANADA. MOST OF THE
SHORTWAVES ARE WEAK EXCEPT FOR A MORE IMPRESSIVE ONE OVER CENTRAL
ALBERTA. THE MAIN SHORTWAVE OF INTEREST IN THE SHORT TERM IS
ORIGINATING OUT OF CONVECTION OVER SOUTHEAST SD AND EASTERN
NEBRASKA. AIRMASS OVER THE FORECAST AREA VARIES GREATLY FROM SOUTH
TO NORTH WITH I-94 BEING A GREAT DIVIDING LINE. TO THE NORTH...DRIER
AIR CHARACTERIZED BY SURFACE DEWPOINTS IN THE 40S AND LOW 50S WAS
PRESENT. FARTHER UP TO THE NORTH...THE 00Z INL SOUNDING REPORTED A
PRECIPITABLE WATER VALUE OF 0.49 INCHES. NOW...SOUTH AND WEST OF
I-94...DEWPOINTS ARE IN THE 60S. THE 00Z SOUNDINGS FROM MPX AND DVN
HAD PRECIPITABLE WATER VALUES AROUND 1.15 INCHES. SEPARATING THESE
TWO AIRMASSES IS A STATIONARY FRONTAL BOUNDARY. ISOLATED
SHOWERS/STORMS HAVE BEEN POPPING UP ALONG/NORTH OF THE BOUNDARY ALL
NIGHT.
SYNOPTIC OVERVIEW...
NORTHWEST FLOW CONTINUES THROUGH THE SHORT TERM PERIOD. THE
CONVECTIVELY INDUCED SHORTWAVE TROUGH APPROACHING SIOUX CITY IA AT
08Z MODELS ARE STRUGGLING WITH GREATLY. MOST MODELS...INCLUDING HI
RESOLUTION RUNS SUCH AS THE HRRR AND HIRES-ARW ARE TOO SLOW.
EXTRAPOLATION HAS THE MCV CROSSING MUCH OF IOWA THIS MORNING.
POTENTIAL THEN EXISTS FOR SOME VERY WEAK RIDGING IN ITS WAKE FOR
THIS AFTERNOON AND TONIGHT...AHEAD OF THE CURRENT ALBERTA SHORTWAVE
WHICH DIGS INTO NORTHERN MN AND WESTERN ONTARIO BY 12Z MONDAY.
TODAY...
DESPITE THIS PERIOD BEING THE BEGINNING OF THE FORECAST...THE
UNCERTAINTY IS QUITE HIGH. MUCH OF THIS UNCERTAINTY STEMS FROM THE
TOO SLOW HANDLING FROM ALL MODELS REGARDING THE MCV APPROACHING
SIOUX CITY IA AS OF 08Z. GENERALLY FOLLOWED AN EXTRAPOLATION
APPROACH COMBINED WITH A SOMEWHAT SPED UP 21.05Z HRRR FORECAST TO
COME UP WITH THE FORECAST TODAY. THE PLAN IS THAT THE MCV SHOULD
TRACK ACROSS DES MOINES AND DAVENPORT THIS MORNING...WITH THE
FORECAST AREA ON THE NORTH SIDE. SHOWERS AND A FEW EMBEDDED
THUNDERSTORMS APPEAR LIKELY...PRIMARILY WEST OF THE MISSISSIPPI
RIVER DURING THE MORNING HOURS. CONCERNED THAT THE DIURNAL EFFECTS
ON LOW LEVEL MOISTURE TRANSPORT MAY CAUSE THE SHOWERS TO WEAKEN SOME
AS WE APPROACH MID-DAY...THUS THE HIGHER CHANCES TO THE WEST. DURING
THE AFTERNOON...IT IS HARD TO SAY WHATS GOING TO OCCUR. WE COULD
EASILY BE IN SUBSIDENCE IN THE WAKE OF THE MCV...PREVENTING MUCH IN
THE WAY OF ADDITIONAL PRECIPITATION. ON THE OTHER HAND...THE
AFTERNOON IS PEAK HEATING AND WITH HIGHER DEWPOINTS TODAY...WE
SHOULD BE ABLE TO BUILD 500-1500 J/KG OF CAPE AS SUGGESTED BY THE
RAP. ANY SHORTWAVE COMING THROUGH THE NORTHWEST FLOW THATS HARD TO
DISCERN AT THIS TIME COULD KICK OFF SHOWERS AND STORMS. ADDITIONALLY
WE SHOULD STILL HAVE THAT STATIONARY FRONTAL BOUNDARY IN THE
FORECAST AREA TO PROVIDE WEAK LOW LEVEL CONVERGENCE. THEREFORE...
HAVE MAINTAINED AT LEAST 40-50 PERCENT CHANCES FOR THE AFTERNOON.
REGARDING TEMPERATURES...ASSUMING SOME SUN TODAY WHICH SHOULD
OCCUR...925MB TEMPS IN THE 18-20C RANGE SUPPORTS HIGHS IN THE 70S TO
NEAR 80.
TONIGHT...
ANY CONVECTION THAT OCCURS THIS AFTERNOON WILL LIKELY HAVE A STRONG
DIURNAL COMPONENT TO IT. THEREFORE...HAVE PRECIPITATION CHANCES
DIMINISHING THROUGH THE EVENING HOURS. HOWEVER...850MB MOISTURE
TRANSPORT DOES INCREASE THROUGH THE NIGHT AHEAD OF THE STRONGER
SHORTWAVE DROPPING INTO NORTHERN MN. CONVECTION WILL LIKELY FORM ON
THE NOSE OF THIS MOISTURE TRANSPORT...WHICH IS FORECAST FROM
NORTHERN MN INTO NORTHERN WI. KEPT SOME 20 PERCENT CHANCES OVERNIGHT
BOTH OVER TAYLOR/CLARK COUNTIES FOR THE NOSE OF THIS MOISTURE
TRANSPORT. ALSO KEPT THE 20 PERCENT CHANCES OVERNIGHT FOR THE
EASTERN HALF OF THE FORECAST AREA...IN THE EVENT ANY DIURNAL
CONVECTION CAN SURVIVE...THOUGH AS THE CHANCE STATES THE CONFIDENCE
IS LOW.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 300 AM CDT SUN JUL 21 2013
SYNOPTIC OVERVIEW...
20.00Z ECMWF/GFS/CANADIAN ALL CONTINUE THE NORTHWEST FLOW PATTERN
THROUGH THE ENTIRE LONG TERM PERIOD. WHAT LOOKED TO BE A POSSIBILITY
OF RIDGING BUILDING TOWARDS THE AREA BRIEFLY THURSDAY INTO FRIDAY IS
NOW COMPLETELY GONE. PART OF THE REASON WE STAY IN NORTHWEST FLOW IS
THE DEVELOPMENT OF AN OMEGA BLOCK OVER WESTERN CANADA BETWEEN
TUESDAY AND WEDNESDAY...WHICH DOES NOT SHOW ANY SIGNS OF BREAKING
DOWN FOR AWHILE. ADDITIONALLY...THERE APPEARS TO BE SOME MODEL
STRUGGLES HANDLING SHORTWAVE TROUGHING COMING DOWN THE EAST SIDE OF
THE OMEGA BLOCK...WHICH PUTS MORE UNCERTAINTY FOR THE FORECAST
THURSDAY AND BEYOND. ONE THING THAT IS STARTING TO BECOME A LITTLE
MORE EVIDENT IS FOR DEEPER TROUGHING OVER THE GREAT LAKES REGION AT
THE END OF NEXT WEEKEND. 500MB STANDARDIZED ANOMALIES FOR 12Z SUNDAY
FROM THE ECMWF/GFS ARE 1.5-2 BELOW NORMAL.
HAZARDS...
THERE COULD BE SOME ISOLATED SEVERE WEATHER LATE MONDAY AFTERNOON
INTO THE EVENING HOURS...ASSOCIATED WITH A COLD FRONT COMING
THROUGH...BUT CONFIDENCE IS LOW AS DESCRIBED BELOW.
MONDAY THROUGH TUESDAY NIGHT...
MUCH OF THE FOCUS HERE IS ON THE MONDAY/MONDAY NIGHT PERIOD.
SHORTWAVE TROUGH OVER NORTHERN MN AND WESTERN ONTARIO AT 12Z MONDAY
MODELS ALL AGREE ON SLIDING IT ACROSS NORTHERN ONTARIO. AS THIS
OCCURS...A COLD FRONT ASSOCIATED WITH IT APPROACHES THE FORECAST
AREA. TIMING ON THIS FRONT VARIES GREATLY. AT 00Z TUESDAY...TIMING
VARIES FROM THE 21.00Z HIRES-ARW HAVING IT WEST OF MINNEAPOLIS TO
THE 21.00Z ECMWF/GFS OVER MINNEAPOLIS AND THE 21.00Z
CANADIAN/NAM/UKMET WHICH ARE OVER LA CROSSE. TRENDS AT LEAST FROM
THE ECMWF/GFS SUGGEST A SLOWER APPROACH MAY BE THE WAY TO GO. THERE
STILL REMAINS UNCERTAINTY ON CONVECTIVE CHANCES WITH THIS
FRONT...
1. A WARM SURGE OF AIR AT 800MB IS STILL INDICATED TO COME OVER THE
FRONT TO PROVIDING POTENTIAL CAPPING
2. THE SHORTWAVE TROUGH SLIDING ACROSS NORTHERN ONTARIO COULD END UP
PUTTING RIDGING OVER THE FRONT FOR THE AFTERNOON AS SUGGESTED BY THE
21.00Z HIRES-ARW.
3. LOW LEVEL CONVERGENCE ON THE FRONT REMAINS IN QUESTION.
4. NOW THE FRONT BEING SLOWER...NOT COMING ACROSS THE FORECAST AREA
AT PEAK HEATING...COULD BE A NEGATIVE FOR PRECIP.
TO ACCOUNT FOR THE SLOWER TREND HAVE LOWERED PRECIPITATION CHANCES
SOME MONDAY AFTERNOON. LEFT THE 40-60 PERCENT CHANCES FOR MONDAY
EVENING AS THAT IS STILL FAIRLY WELL AGREED UPON BY GUIDANCE...THEN
CHANCES DIMINISHING AFTER MIDNIGHT WITH LOSS OF HEATING AND THE
FRONT PROGRESSING THROUGH THE AREA. DRY WEATHER FOLLOWS IN THE WAKE
OF THE FRONT FOR TUESDAY AND TUESDAY NIGHT WHILE HIGH PRESSURE
BUILDS IN AT THE SURFACE. 925MB TEMPS CLIMBING TO 21-24C AHEAD OF
THE FRONT ON MONDAY PLUS SUNSHINE WILL ALLOW HIGHS TO CLIMB INTO THE
80S. MAY EVEN SEE 90 IN A FEW SPOTS IF MORE SUN OCCURS. MONDAY LOOKS
HUMID AS WELL AS NEAR 70 DEGREE DEWPOINTS ADVECT IN AT THE SURFACE.
COOLER HIGHS ON THE WAY FOR TUESDAY AS 925MB TEMPS TUMBLE TO 17-20C.
TUESDAY NIGHT LOWS HAVE POTENTIAL TO GET INTO THE 40S AT THE TYPICAL
COLDER SPOTS...DUE TO LIGHT WINDS AND PRECIPITABLE WATER VALUES
FALLING TO 0.5-0.75 INCHES.
WEDNESDAY THROUGH SATURDAY NIGHT...
20.00Z ECMWF/GFS/CANADIAN ARE SUGGESTING NUMEROUS WEAK SHORTWAVES
DROP SOUTHEAST ACROSS THE FORECAST AREA WEDNESDAY THROUGH THURSDAY
IN THE NORTHWEST FLOW ALOFT. HARD TO SAY IF ANY OF THESE ARE GOING
TO DO ANYTHING PRECIP WISE. 20.00Z CANADIAN AND 19.12Z ECMWF WANT TO
BRING SOME SHOWERS ACROSS WEDNESDAY NIGHT AND THURSDAY...THOUGH THE
20.00Z ECMWF BACKED OFF. WOULD THINK A DRIER SCENARIO IS MORE LIKELY
GIVEN THE DRY AIRMASS COMING IN TUESDAY NIGHT/WEDNESDAY WITH
CANADIAN HIGH PRESSURE IN PLACE. NEVERTHELESS...DID HONOR A 20
PERCENT CHANCE MAINLY ON THURSDAY JUST IN CASE. CHANCES INCREASE A
LITTLE FOR THURSDAY NIGHT AND FRIDAY WHERE IT APPEARS A COLD FRONT
WILL CROSS THE AREA...ASSOCIATED WITH A POTENT UPPER TROUGH DROPPING
OVER MANITOBA AND NORTHERN ONTARIO. SOME OF THIS UPPER TROUGH LOOKS
TO SWING ACROSS THE FORECAST AREA FRIDAY NIGHT AND SATURDAY...THUS
STILL NEED TO CONTINUE AT LEAST 20 PERCENT CHANCES. BEING IN THIS
NORTHWEST FLOW PATTERN COMBINED WITH EVEN DEEPER TROUGHING FORMING
OVER THE WEEKEND SUGGESTS BELOW NORMAL TEMPERATURES. BY 12Z
SUNDAY...BOTH THE 20.00Z ECMWF AND GFS DEPICT 850MB TEMPS FALLING TO
6-9C...CHILLY RELATIVELY SPEAKING FOR THE END OF JULY.
&&
.AVIATION...THROUGH 18Z MONDAY
105 PM CDT SUN JUL 21 2013
MESOSCALE VORTICITY MAX SPINNING INTO NORTHEAST IA EARLY THIS
AFTERNOON AND HELPING TO ENHANCE SHOWERS AND THUNDERSTORMS ACROSS
THE LOCAL AREA. LOOKS LIKE THUNDER WILL REMAIN NORTH OF BOTH TAF
LOCATIONS FOR THE MOST PART. CANNOT COMPLETELY RULE OUT A RUMBLE
OF THUNDER...BUT CHANCE IS SO SMALL THAT IT WAS NOT INCLUDED IN
THE TAFS. ONCE THE MCV MOVES PAST...ANTICIPATE THAT THE SHOWER
ACTIVITY WILL DISSIPATE. SOME MODELS DO INDICATE THAT ADDITIONAL
DEVELOPMENT WILL OCCUR...BUT DO NOT FEEL THIS WILL IMPACT EITHER
TAF LOCATION.
WITH RAIN TODAY...AND GENERALLY WEAK FLOW OVERNIGHT...ANTICIPATE
SOME LIGHT FOG/MIST TO FORM. MAINTAINED MENTION IN THE FORECASTS.
NEXT DISTURBANCE AND ASSOCIATED COLD FRONT WILL MOVE THROUGH
DURING THE AFTERNOON HOURS ON MONDAY. LATER TAF ISSUANCES WILL
HAVE TO ACCOUNT FOR CONVECTIVE POTENTIAL NEAR AND AHEAD OF THE
FRONT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...MW