Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 07/18/13
AREA FORECAST DISCUSSION
NWS TUCSON AZ
902 AM MST TUE JUL 16 2013
.SYNOPSIS...A WEATHER SYSTEM FROM THE PLAINS STATES WILL MOVE WEST
AND CONTINUE TO BRING PERIODS OF HEAVY RAIN...ESPECIALLY TO AREAS
NEAR AND WEST OF TUCSON TROUGH TONIGHT. THIS SYSTEM WILL THEN
SETTLE OVER NORTHERN MEXICO FOR THE REST OF THE WEEK. THIS WILL KEEP
A MOIST SOUTHEAST FLOW ALOFT...THUS KEEPING THE CHANCES FOR
AFTERNOON AND EVENING THUNDERSTORMS.
&&
.DISCUSSION...LET US BEGIN THIS MORNING WITH A BRIEF RECAP OF THE
PRECIP FROM YESTERDAY THROUGH OVERNIGHT HOURS. Q2 PRECIPITATION
ANALYSIS...WHICH COMBINES RADAR ESTIMATES WITH REAL
OBSERVATIONS...SUGGESTS WIDESPREAD RAINFALL TOTALS OF 0.75 TO 2
INCHES IN THE LAST 48 HOURS BASICALLY FROM AROUND TUCSON EAST. SOME
LOCATIONS HAVE HAD OVER 4 INCHES OF RAIN IN THE LAST 48
HOURS...INCLUDING MT. LEMMON.
GIVEN THE ANTECEDENT CONDITIONS IN PLACE...WE ARE CONCERNED THAT
FLASH FLOODING WILL BE POSSIBLE TODAY BUT IT MAY TAKE LESS RAINFALL
THAN NORMAL TO PRODUCE RUNOFF IN SEVERAL AREAS.
CURRENT RADAR IMAGERY SHOWS A LINE OF WEAK ECHOS STRETCHING FROM
TOMBSTONE TO THE NORTHWEST INTO SOUTHWEST PINAL COUNTY. THE LATEST
HRRR AND THE UOFA WRF NAM BOTH SEEM TO HANDLE THE LIGHT PRECIP WELL.
THE BIG QUESTION IS HOW WILL TODAY EVOLVE. WILL THE HIGH MOISTURE
CONTENT...SATELLITE ESTIMATED PRECIP WATER VALUES OF 1.6 INCHES PLUS
ACROSS ALL OF SE ARIZONA...AND CLOUD COVER BE TOO MOIST AND LIMIT
THE CONVECTIVE POTENTIAL TODAY OR WILL THE APPROACHING UPPER TROUGH
PROVIDE ENOUGH LIFT TO OVERCOME THE LACK OF HEATING. THE UPPER LOW
IS STILL TRACKING ALONG AS EXPECTED AND SHOULD PUSH INTO NEW MEXICO
TODAY. THE HI RES MODELS DO RESPOND TO THE APPROACHING LOW AND SHOW
MORE ACTIVITY THROUGH THE DAY...BUT THERE IS SOME INCONSISTENCY OVER
THE FAVORED AREAS. THE HRRR SHOWS A FAIRLY WIDESPREAD MODERATE
PRECIP EVENT WITH A FEW EMBEDDED HEAVY PRECIP CORES...WILE THE NAM
WRF DATA FOCUSES THE ACTIONS ACROSS PIMA AND PINAL COUNTIES GIVING
THE EASTERN ZONES A BREAK.
GIVEN THE WET PATTERN IN PLACE WITH THE UPPER TROUGH STILL HEADING
THIS DIRECTION...I FAVOR A MORE WIDESPREAD EVENT TODAY. EITHER
WAY...BOTH MODELS SUGGEST THE ACTIVITY WILL DIMINISH AFTER 00Z TO
02Z. THAT ALSO SEEMS REASONABLE.
&&
.CLIMATE...IN CLIMATE NEWS...DOUGLAS AIRPORT HAS RECEIVED 7.85
INCHES OF RAIN SO FAR THIS MONTH. THIS MAKES JULY THE WETTEST MONTH
ON RECORD...DATING BACK TO 1948. THE PREVIOUS WETTEST MONTH WAS
AUGUST 1959. WE ARE ONLY TWO WEEKS INTO JULY SO HITTING 8 INCHES
THIS MONTH IS WELL WITHIN THE REALM OF POSSIBILITY.
&&
.AVIATION...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL
OCCUR INTO THIS EVENING. PRECIP WILL DECREASE IN COVERAGE AFTER
ABOUT 17/03Z WITH ONLY ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS LATE TONIGHT THRU WEDNESDAY MORNING. AT THIS TIME
APPEARS THAT KTUS AND KOLS HAVE THE BEST CHANCE OF TSRA/SHRA INTO
THIS EVENING WITH LESSER CHANCES FOR KDUG. WIND GUSTS TO 50-60 KTS
WILL BE POSSIBLE WITH THE STRONGER TSRA. OTHERWISE...CLOUD DECKS
GENERALLY 8-12K FT AGL AND SURFACE WIND MOSTLY LESS THAN 10 KTS THRU
WEDNESDAY MORNING OR 17/18Z. AVIATION DISCUSSION NOT UPDATED FOR TAF
AMENDMENTS.
&&
.FIRE WEATHER...A LOW PRESSURE SYSTEM OVER THE TEXAS PANHANDLE THIS
MORNING WILL MOVE SOUTHWESTWARD INTO NORTHERN SONORA BY MIDDAY
THURSDAY. THIS SYSTEM IN COMBINATION WITH AMPLE MOISTURE WILL
PROVIDE SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS INTO THIS
EVENING. THE POTENTIAL EXISTS FOR HEAVY RAINFALL INTO THIS EVENING.
THEREAFTER...SOMEWHAT LESS COVERAGE OF RAINFALL IS EXPECTED STARTING
WEDNESDAY. HOWEVER...ADEQUATE MOISTURE WILL BRING SCATTERED SHOWERS
AND THUNDERSTORMS TO THE AREA INTO THIS WEEKEND.
&&
.PREV DISCUSSION...WATER VAPOR IMAGERY DEPICTS THE UPPER LOW TO BE
ON TRACK WITH MODEL RUNS FROM LAST FEW DAYS. LOW IS SPINNING OVER
TEXAS PANHANDLE AND MOVING WEST...WITH THE LATEST BLENDED TOTAL
PRECIPITABLE WATER IMAGERY SHOWING PW`S IN EXCESS OF 1.5 INCHES
ACROSS MUCH OF SOUTHEAST ARIZONA AND VALUES NEAR 1.7 INCHES ACROSS
PORTIONS OF GRAHAM AND COCHISE COUNTIES. LATEST IR SATELLITE IMAGERY
SHOWS EXTENSIVE CLOUDINESS COVERING MUCH OF EASTERN ARIZONA WITH THE
CLOUDS TAPERING OFF FARTHER WEST ACROSS WESTERN ARIZONA.
RECENT RADAR IMAGERY IS DETECTING SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS THAT GENERALLY EXTEND FROM THE NORTHEAST PORTION OF MY
FORECAST AREA...MAINLY FROM EASTERN PINAL COUNTY THROUGH NORTHERN
GREENLEE COUNTY AND SOUTHWARD ACROSS MUCH OF GRAHAM AND COCHISE
COUNTIES...WITH THE ACTIVITY ALSO WESTWARD INTO EXTREME EASTERN
PORTIONS OF PIMA COUNTY. THE HEAVIEST RAIN OF LATE HAS BEEN FOCUSED
OVER THE CATALINA MOUNTAINS OF NORTHEAST PIMA COUNTY WHERE A SMALL
STREAM FLOOD ADVISORY CONTINUES FOR MUCH OF EASTERN PIMA COUNTY...
WHICH INCLUDES THE SANTA CATALINA MOUNTAINS AS WELL AS THE ENTIRE
TUCSON METRO AREA THROUGH 245 AM MST.
MODELS INDICATE THAT THE UPPER LOW WILL CONTINUE TO MOVE SOUTHWEST
TODAY...REACHING SOUTHEAST NEW MEXICO BY LATE THIS EVENING AND
WEAKEN IN THE PROCESS. MODELS SEEM TO SUGGEST THAT AS THIS OCCURS...
THE BAND OF PRECIPITATION ON THE WESTERN FLANK OF THE LOW WILL SHIFT
A TAD WESTWARD TODAY...WHILE AREAS TO THE EAST MAY SEE A SLIGHT
DOWNWARD TREND IN SHOWER AND THUNDERSTORM ACTIVITY...MAINLY LATE IN
THE DAY. INHERITED FLASH FLOOD WATCH AND ITS TIMING SEEMS TO BE ON
TRACK WITH IT ENDING EARLY THIS EVENING. HOWEVER...THIS IS SOMETHING
THE DAY SHIFT WILL HAVE A BETTER HANDLE ON AS THIS SYSTEM EVOLVES
THROUGHOUT THE DAY.
MADE SOME TWEAKS TO THE POP FORECAST BASED ON THE LATEST MODEL
DATA...BUT CHANGES WERE FAIRLY MINOR. STILL LOOKING AT SLIGHT
CHANGES POPS THIS MORNING FOR THE FAR WESTERN PORTIONS OF THE
FORECAST AREA...SPECIFICALLY WESTERN PIMA COUNTY...WITH A STEEP POP
GRADIENT AS YOU GO EAST...WITH POPS IN THE LIKELY TO CATEGORICAL
RANGE FOR THE EASTERN ZONES. SIMILAR CHANCES THIS AFTERNOON...BUT
THE SHOWERS AND STORMS WILL PUSH A BIT FARTHER WEST LATE THIS
AFTERNOON AND INTO THE EARLY EVENING HOURS.
BEYOND TODAY MODELS SHOW THIS LOW TRAVERSING NORTHERN MEXICO WHICH
WILL PROVIDE A SOUTHEAST FLOW ACROSS THE DESERT SOUTHWEST. AS A
RESULT...EXPECT SCATTERED SHOWERS AND THUNDERSTORMS MAINLY EACH
AFTERNOON AND EVENING THROUGH NEXT MONDAY.
HIGH TEMPERATURES GENERALLY 6 TO 8 DEGS BELOW NORMAL TODAY...THEN 3
TO 5 DEGS BELOW NORMAL THEREAFTER. LOW TEMPERATURES THROUGHOUT THE
FORECAST PERIOD WILL BE NEAR NORMAL.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH THIS EVENING FOR AZZ507>514.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
PUBLIC...BROST
AVIATION/FIRE WEATHER...FRANCIS
AREA FORECAST DISCUSSION
NWS NEW YORK NY
450 PM EDT TUE JUL 16 2013
.SYNOPSIS...
HOT AND HUMID WEATHER WILL CONTINUE THROUGH THE END OF THE WEEK
WITH WEAK HIGH PRESSURE REMAINING ACROSS THE REGION THROUGH
WEDNESDAY NIGHT. A WEAK TROUGH OF LOW PRESSURE WILL DEVELOP ACROSS
THE AREA FOR THE REST OF THE WEEK. A COLD FRONT APPROACHES ON
SATURDAY AND MOVES SOUTH OF THE REGION ON SUNDAY AS HIGH PRESSURE
RETURNS FOR EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
WEAK HIGH PRESSURE ACROSS REGION WITH SHORTWAVE MOVING THROUGH NEW
ENGLAND THIS EVENING. UPPER LEVEL RIDGE STAYS ANCHORED TO OUR WEST.
HEAT AND HUMIDITY STILL IN PLACE WITH INCREASING MOISTURE CONTENT
WITHIN BOUNDARY LAYER. SEA BREEZE MORE SUPPRESSED TODAY SIMILAR TO
YESTERDAY. A SHORTWAVE MOVING ACROSS NEW ENGLAND THIS EVENING WILL
ALLOW FOR A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS AHEAD AND
ALONG IT. SOME MESO MODELS SUCH AS THE HRRR AND WRF NMM ARE
INDICATING THIS POSSIBILITY. OTHERWISE...DRY AND HUMID WEATHER
CONTINUES TONIGHT. LOWS WERE PREFERRED WITH WARMER
GUIDANCE...KEEPING TEMPERATURES IN THE 70S FOR MUCH OF THE AREA
TONIGHT AND UPPER 60S FOR INTERIOR AND RURAL SECTIONS.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
UPPER LEVEL RIDGE TO OUR WEST BEGINS TO SLOWLY FLATTEN WITH HIGH
PRESSURE AT THE SURFACE CONTINUING TO WEAKEN. A SURFACE TROUGH
DEVELOPS ACROSS THE AREA WEDNESDAY...WITH A BETTER SOUTHERLY FLOW
DEVELOPING ACROSS COASTAL SECTIONS. SO A BETTER CHANCE FOR SEA
BREEZES DURING THE AFTERNOON FOR AT LEAST IMMEDIATE COASTAL
SECTIONS. FLOW TURNS MORE SOUTHWEST WEDNESDAY NIGHT. POSSIBLE
SHOWER OR THUNDERSTORM ACROSS THE INTERIOR BUT NOT ENOUGH
CONFIDENCE TO INSERT IN FORECAST.
HIGHS WILL BE WELL INTO THE 90S WITH DEWPOINTS HIGHEST ALONG THE
URBAN CORRIDOR AND THE LOWER HUDSON VALLEY AS WELL AS INTERIOR
SOUTHERN CONNECTICUT. UPPER 80S TO LOWER 90S MAX TEMPS TOWARDS THE
COASTLINE IN COMBINATION WITH THE DEWPOINT WILL KEEP HEAT INDICES
AT LEAST A FEW DEGREES BELOW 100 DEGREES...THE CRITERION FOR HEAT
ADVISORY OUTSIDE OF NYC. HOWEVER...URBAN NORTHEAST NEW JERSEY AS
WELL AS NEW YORK CITY...THE LOWER HUDSON VALLEY...AND INTERIOR
SOUTHERN CONNECTICUT WILL BE APPROACHING 100 DEGREES FOR HEAT
INDICES SO HEAT ADVISORIES EXTENDED THROUGH EARLY WEDNESDAY
EVENING FOR THESE LOCATIONS. THERE IS SOME UNCERTAINTY DEPENDING
ON DAYTIME MIXING...WHICH IS FORECAST TO BE UP TO AROUND 850 MB
AGAIN. HOWEVER...MOISTURE IS FORECAST TO INCREASE RELATIVE TO
TODAY AND THIS MAKES SENSE DUE TO A GREATER SOUTHERLY SYNOPTIC
FLOW AND LESS SYNOPTIC NORTHERLY FLOW.
FOR WEDNESDAY NIGHT...SIMILAR TEMPS TO PREVIOUS NIGHT WITH DRY
WEATHER IN PLACE.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
DEEP LAYERED RIDGING WILL REMAIN OVER THE EASTERN CONUS THROUGH
FRIDAY. BY FRIDAY NIGHT...THERE IS EXCELLENT AGREEMENT AMONG THE
OPERATIONAL AND ENSEMBLE GUIDANCE OF THE RIDGE BREAKING DOWN AND
SHIFTING OFFSHORE AS UPPER LEVEL HEIGHTS BEGIN TO FALL AHEAD OF A
TROUGHING BUILDING INTO THE NE US. THIS TROUGH SENDS A COLD FRONT
THROUGH THE AREA SATURDAY/SATURDAY NIGHT.
HOT AND HUMID CONDITIONS WILL CONTINUE INTO SATURDAY. H85 TEMPS ARE
FORECAST TO RANGE FROM 18C TO 20C ON THURSDAY AND FRIDAY HELPING TO
MAKE THESE DAYS THE HOTTEST OF THE EXTENDED PERIOD. HEAT ADVISORY
HAS BEEN EXTENDED UNTIL 8PM THURSDAY FOR NEW YORK CITY. FOR LOWER
HUDSON VALLEY...NE NJ...AND INTERIOR CT...IT IS POSSIBLE HEAT
ADVISORY CRITERIA WILL BE MET THURSDAY BUT CONFIDENCE IS LOW AT THIS
TIME. ONE POSSIBLE CAVEAT IS HOW MUCH DRIER AIR MIXES DOWN. SIMILAR
CONDITIONS/CONCERNS EXIST ON FRIDAY SO WILL NEED TO CONTINUE TO
MONITOR TRENDS. WITH A SURFACE TROUGH AND HIGH AMOUNTS OF
INSTABILITY THURS AND FRI...A SHOWER OR THUNDERSTORM CANNOT BE RULED
OUT. THESE WILL LIKELY BE PULSE IN NATURE AS SHEAR IS MINIMAL.
COLD FRONT THEN APPROACHES SATURDAY BRINGING MUCH BETTER CHANCES FOR
SHOWERS AND STORMS. WITH HEIGHT FALLS OCCURRING ALOFT AND BETTER
SYNOPTIC LIFT...THE CHANCES FOR SHOWERS AND STORMS INCREASE.
INGREDIENTS MAY BE PRESENT TO PROMOTE SEVERE WEATHER SAT WITH THE
FRONT. PRIMARY THREATS AT THIS TIME APPEAR TO BE DAMAGING WINDS. ANY
STORM MAY ALSO PRODUCE HEAVY RAINFALL AS PWATS APPROACH 2 INCHES
SATURDAY.
THE FRONT SHOULD MOVE SOUTH OF THE AREA SUNDAY. HOWEVER...12Z GFS
DOES SLOW ITS PROGRESSION WITH A WAVE DEVELOPING ALONG IT. THE
LATEST 12Z ECMWF AND 12Z CMC DO NOT DEPICT THIS SCENARIO...BUT DO
HINT AT A SLIGHTLY SLOWER PROGRESSION SOUTHWARD.
THEREFORE...LINGERED CHANCE POPS MAINLY ACROSS SOUTHERN ZONES
SUNDAY.
A RETURN TO MORE SEASONABLE CONDITIONS EXPECTED FOR EARLY NEXT WEEK
AS HIGH PRESSURE BUILDS INTO THE AREA.
&&
.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
CONCERN IS WHETHER SEA BREEZE CAN MAKE IT THROUGH KJFK OVER THE
NEXT COUPLE OF HOURS. SEA BREEZE NOTICEABLE ON TJFK RADAR JUST
SOUTH OF THE TERMINAL AND ALONG THE BARRIER ISLANDS. POTENTIAL
EXISTS FOR THE SEA BREEZE TO COME THROUGH BETWEEN 23-24Z AS TEMPS
DECREASE...AND THEN WINDS WOULD SHIFT TO THE SOUTH. BY
02-03Z...WINDS WILL BE VRB AT 5 KT OR LESS.
OTHERWISE...HIGH PRES REMAINS OVER THE AREA.
GENERALLY NNE TO NNW FLOW AT 8-12 KT WITH OCNL GUSTS OF 16-18 KT
OVER THE TERMINALS. WINDS BECOME VRB AT 5 KT OR LESS AFT 02Z...AND
THEN NE TO SE WINDS INCREASE TO 5-7 KT AFT 14Z WEDNESDAY.
VFR THROUGH THE TAF PERIOD.
...NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: LOW CONFIDENCE ON SEA BREEZE THIS EVENING.
BEST TIMING WOULD BE BTWN 23-24Z...IF THE SEA BREEZE DOES MOVE
THROUGH THE TERMINAL. HIGH CONFIDENCE WINDS TO THE RIGHT OF 310
TRUE OTHERWISE.
KLGA FCSTER COMMENTS: HIGH CONFIDENCE WINDS TO THE RIGHT OF 310
TRUE THROUGH THIS EVENING. VERY LOW CHANCE OF SEA BREEZE DURING
THE LATE AFTERNOON/EARLY EVENING HOURS.
KEWR FCSTER COMMENTS: HIGH CONFIDENCE WINDS TO THE RIGHT OF 310
TRUE THROUGH THIS EVENING. VERY LOW CHANCE OF SEA BREEZE DURING
THE LATE AFTERNOON/EARLY EVENING HOURS.
KTEB FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.
KHPN FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.
KISP FCSTER COMMENTS: HIGH CONFIDENCE WINDS TO THE RIGHT OF 310
TRUE THROUGH THIS AFTERNOON. LOW CHANCE SEA BREEZE IMPACTS
KISP...BUT IF IT DOES...IT WOULD OCCUR BETWEEN 20-22Z.
.OUTLOOK FOR 18Z WEDNESDAY THROUGH SUNDAY...
.WEDNESDAY-WEDNESDAY NIGHT...VFR.
.THURSDAY AND FRIDAY NIGHT...VFR. SLIGHT CHANCE SHRA/TSTM MAINLY
N AND W OF NYC DURING THE AFTERNOON/EVENING.
.SATURDAY...MAINLY VFR...BUT THE POTENTIAL LIES FOR WITH MVFR OR
LOWER CONDS IN STRONG TO SEVERE CONVECTION.
.SUNDAY...IMPROVING CONDS.
&&
.MARINE...
SUB SCA CONDITIONS ARE EXPECTED TO PREVAIL THROUGH WEDNESDAY NIGHT WITH
A WEAK PRESSURE GRADIENT IN PLACE.
A 15-20KT SW FLOW DEVELOPS OVER THE WATERS WITH GUSTS LIKELY
APPROACHING SCA LEVELS FRIDAY INTO SATURDAY. SEAS WILL ALSO BUILD TO
SCA LEVELS DURING THIS TIME. SUNDAY INTO MONDAY...WINDS SHOULD
REMAIN BELOW SCA LEVELS WITH MARGINAL SCA SEAS.
&&
.HYDROLOGY...
DRY CONDITIONS ARE EXPECTED THROUGH WEDNESDAY NIGHT.
A MOIST AIRMASS OVER THE AREA THURSDAY INTO FRIDAY BRINGS THE
POTENTIAL FOR HEAVY DOWNPOURS. HOWEVER...THUNDERSTORMS SHOULD REMAIN
ISOLATED LIMITING ANY FLASH FLOODING POTENTIAL. THE CHANCE FOR FLASH
FLOODING INCREASES ON SATURDAY WITH BETTER THUNDERSTORM COVERAGE AND
PRECIPITABLE WATERS INCREASING TO AROUND 2 INCHES.
&&
.CLIMATE...
TUESDAY JULY 16 2013 RECORD MAXIMUM TEMPERATURES
SITE RECORD FORECAST HIGH
BRIDGEPORT 94 (1983, 1952) 95
ISLIP 93 (1999) 95
LAGUARDIA 97 (1980) 97
KENNEDY 100 (1983) 95
CENTRAL PARK 99 (1980) 96
NEWARK 101 (1988) 97
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...HEAT ADVISORY UNTIL 8 PM EDT WEDNESDAY FOR CTZ005>008.
HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR CTZ009>012.
NY...HEAT ADVISORY UNTIL 8 PM EDT WEDNESDAY FOR NYZ067>071.
HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ078-080-177-
179.
HEAT ADVISORY UNTIL 8 PM EDT THURSDAY FOR NYZ072>075-176-178.
NJ...HEAT ADVISORY UNTIL 8 PM EDT WEDNESDAY FOR NJZ006-104-106-108.
HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NJZ004-103-105-
107.
MARINE...NONE.
&&
$$
SYNOPSIS...JM/DS
NEAR TERM...JM
SHORT TERM...JM
LONG TERM...DS
AVIATION...MPS
MARINE...JM/DS
HYDROLOGY...JM/DS
CLIMATE...
AREA FORECAST DISCUSSION
NWS TAUNTON MA
435 PM EDT TUE JUL 16 2013
.SYNOPSIS...
HOT AND HUMID WEATHER WILL CONTINUE THIS WEEK WITH ONLY WIDELY
SCATTERED SHOWERS OR THUNDERSTORMS ON WED. CHANCES FOR SHOWERS
AND THUNDERSTORMS WILL INCREASE THU...FRI AND ESPECIALLY SAT AS A
COLD FRONT APPROACHES FROM THE GREAT LAKES. RELIEF FROM THE HEAT
AND HUMIDITY WILL ARRIVE ON SUNDAY BEHIND A STRONG COLD FRONT AND
LAST THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AS OF LATE THIS AFTERNOON THERE WERE ONLY A FEW SHOWERS ALONG THE
SEACOAST OF NH. SATELLITE SHOWED THE CUMULUS FIELD ALREADY
BEGINNING TO ERODE...SO DO NOT EXPECT ANYTHING MORE THAN AN
ISOLATED SHOWER IN NORTHEAST MA OR SOUTHERN NH BEFORE SUNSET.
DIURNAL DEWPOINT RISE AND WARM TEMPERATURES WILL LEAD TO ANOTHER
WARM HUMID NIGHT TONIGHT WITH MANY LOCATIONS REMAINING IN THE
UPPER 60S TO LOWER 70S. THERE WAS LITTLE IN THE WAY OF FOG
OVERNIGHT LAST NIGHT AND WITHOUT ONSHORE FLOW ACROSS THE AREA...
AM NOT EXPECTING MORE THAN A TOUCH OF FOG OVERNIGHT.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
WED WILL BE SIMILAR TO TODAY...WITH A MOSTLY CLEAR START AND
TEMPERATURES RAPIDLY CLIMBING INTO THE LOWER TO MID 90S.
TEMPERATURES WILL BE A COUPLE OF DEGREES WARMER AND DEWPOINTS WILL
BE A DEGREE OR TWO HIGHER...WHICH WILL LEAD TO HEAT INDICES
REACHING 98-102 OVER MOST OF SOUTHERN NEW ENGLAND...INCLUDING
SOUTHERN NH...WITH THE ONLY EXCEPTIONS BEING CAPE COD AND THE
ISLANDS. THUS HAVE ISSUED A HEAT ADVISORY FOR MOST OF THE REGION
FOR WED AFTERNOON AND EARLY EVENING.
WINDS WILL STILL BE LIGHT...BUT SHOULD TURN TO A SOUTHERLY
DIRECTION. ALTHOUGH HIGHS REACHED 90 ON BLOCK ISLAND TODAY...WITH
LIGHT SOUTHERLY WINDS EXPECTED OFF OF THE COOLER WATERS WED...HAVE
ONLY FORECAST MID 80S THERE...IT COULD POTENTIALLY BE COOLER THAN
THAT.
THERE IS A CHANCE OF AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS
ON WED...MAINLY IN SOUTHERN NH AND NORTHERN MA...AS LOW PRESSURE
MOVES ACROSS SOUTHERN QUEBEC AND A TROUGH OF LOW PRESSURE PASSES
ACROSS NEW ENGLAND. UPPER LEVEL HIGH PRES RIDGE STILL IN CONTROL
THOUGH WITH CAP AROUND H7 AND UNFAVORABLE MID LEVEL LAPSE RATES.
SB CAPE VALUES LOOK TO BE A BIT HIGHER THANKS TO THE INCREASING
MOISTURE WITHIN THE COLUMN...AVERAGING ABOUT 1500-2000 J/KG.
THEREFORE...WENT WITH 25 TO 35 PCT CHANCE IN NORTHEAST MA/SOUTHERN
NH AND 20 PCT FARTHER TO THE SOUTH INTO NORTHERN CT/RI/SOUTHEAST
MA.
WEDNESDAY EVENING...ANY CONVECTION WILL DIMINISH AGAIN BY SUNSET.
ANOTHER WARM AND MUGGY NIGHT WITH CLEAR TO PARTLY CLOUDY SKIES IS
EXPECTED. PERHAPS A LITTLE MORE PATCHY FOG AS THE AIR MASS GETS
EVEN MORE HUMID. LOWS MAINLY UPPER 60S TO MID 70S.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
HEADLINES...
* HOT/HUMID THU INTO SAT WITH SCATTERED T-STORMS
* SEVERE STORMS POSSIBLE AHEAD OF A COLD FRONT SAT
* SEASONABLE AND DRY SUNDAY INTO THE BEGINNING OF NEXT WEEK
DETAILS...
NOT MUCH CHANGE IN OUR FORECAST THINKING FROM PREVIOUS SHIFTS.
MODELS REMAIN IN GOOD OVERALL AGREEMENT SHIFTING H5 HIGH SOUTH
AND WEST TOWARDS THE FOUR-CORNERS REGION ALLOWING FOR FALLING
HEIGHTS ACROSS NEW ENGLAND. THIS RESULTS IN THE RETURN OF THE
NORTHERN STREAM AS DOMINANT INFLUENCE AND SUBSEQUENTLY A MORE
ACTIVE PATTERN.
THURSDAY...
MODELS KEY ON LEE TROUGH BECOMING FOCUS FOR SCATTERED AFTERNOON
CONVECTION. SURFACE-BASED CAPES REACH 1500 J/KG WITH DECENT MID
LEVEL LAPSE RATES AROUND 6C/KM...BUT 0-6KM SHEAR IS MARGINAL AT
BEST. STILL NEED TO OVERCOME RATHER WARM MID LEVEL TEMPERATURES...
SO NOT CONFIDENT THAT STORM COVERAGE WILL BE ALL THAT GREAT. KEPT
CHANCE POPS FOR SCATTERED AFTERNOON THUNDERSTORMS WITH CONTINUED
MENTION OF HEAVY RAIN.
HIGH CAPE ENVIRONMENT FAVORS STRONG TO ISOLATED SEVERE STORMS...
BUT OVERALL SEVERE THREAT APPEARS TO BE LIMITED. PRECIPITABLE
WATER VALUES APPROACHING 2 INCHES...WHICH IS AROUND +2 STANDARD
DEVIATIONS...MEANS POTENTIAL FOR HEAVY RAINFALL AND ISOLATED
FLOODING IN STORMS.
HIGHS IN 90S AWAY FROM S COAST COMBINED WITH DEW POINTS IN LOWER
70S WILL ONCE AGAIN YIELD HEAT INDICES AROUND 100.
FRIDAY...
FLOW ALOFT BECOMES FLATTER WHICH SHOULD ALLOW ANY UPSTREAM
ACTIVITY TO PASS TO OUR N. HOWEVER WE REMAIN IN UNSTABLE AIRMASS
WITH BETTER CONVECTIVE POTENTIAL THAN THU. MODELS SHOW SURFACE
BASED CAPES 2000-3000 J/KG AND MID LEVEL LAPSE RATES OVER 6C/KM.
AXIS OF GREATEST 0-6KM SHEAR REMAINS ACROSS NORTHERN NEW ENGLAND
BUT SW NH AND NORTHERN MA ARE ON PERHIPHERY OF THIS AXIS WITH
VALUES OF 30-35KT. IN ADDITION WE ARE IN FAVORABLE RR QUAD OF
UPPER JET. ONLY LIMITING FACTOR APPEARS TO BE WARM MID LEVEL TEMPS
/+11C AT 700 MB/ BUT COLDER AIR ALOFT SHOULD BE ABLE TO
COMPENSATE.
EXPECT SCATTERED STORMS TO DEVELOP FRI AFTERNOON ACROSS MUCH OF
SOUTHERN NEW ENGLAND...ASIDE FROM IMMEDIATE S COAST WHICH WILL BE
MORE STABLE DUE TO SW FLOW. SEVERE POTENTIAL IS SOMEWHAT BETTER
THAN THU WITH BETTER POSSIBILITY OF DAMAGING WINDS DUE TO BOWING
SEGMENTS OR LINES. ALSO HAVE CONTINUED POTENTIAL FOR HEAVY
RAINFALL AND ISOLATED FLOODING.
INCREASING SW FLOW WILL RESULT IN WARMER DAY THAN THU. HIGHS
SHOULD TOP OUT IN LOW-MID 90S /GIVEN MODEL 2M TEMPERATURES/
COMBINED WITH DEW POINTS IN LOW-MID 70S SHOULD YIELD HEAT INDICES
OF 100-105. NOT CONFIDENT ENOUGH TO ISSUE EXCESSIVE HEAT WATCH BUT
WE MAY NEED TO DO SO IF THIS BECOMES MORE CERTAIN.
SATURDAY...
BEST POTENTIAL FOR ORGANIZED CONVECTION AS STRONG COLD FRONT
APPROACHES FROM GREAT LAKES. SOME QUESTION AS TO WHETHER OR NOT
ANY EARLY MORNING CONVECTION WILL INHIBIT SIGNIFICANT
DESTABILIZATION DURING AFTERNOON. PATTERN SEEMS TO FAVOR AT LEAST
MORNING SHOWERS/STORMS NEAR S COAST...THEN WE SEE A BREAK BEFORE
ADDITIONAL STORMS FIRE DURING AFTERNOON AND EVENING.
NO REAL CHANGE IN THINKING FROM SPC DAY 4 OUTLOOK AND PREVIOUS
DISCUSSION. EXPECTED INSTABILITY COUPLED WITH BULK SOUTHWESTERLY
UNI-DIRECTIONAL SHEAR AROUND 35 KTS FAVORS MULTICELLS AND LINE
ECHO WAVE PATTERNS WITH DAMAGING WINDS MAIN THREAT. ALSO NEED TO
BE AWARE OF CONTINUED FLASH FLOOD POTENTIAL WITH PRECIPITABLE
WATER VALUES NEAR 2 INCHES.
SUNDAY INTO THE EARLY WEEK...
COLD FRONT WILL HEAD OFFSHORE SUN MORNING...PERHAPS NOT UNTIL SUN
AFTERNOON ON CAPE COD. COOLER AND DRIER AIR WILL FOLLOW ON NW
WINDS LATER SUN. FRONT MAY BECOME STATIONARY AS IT RUNS UP INTO
RIDGING OVER WESTERN ATLANTIC. THIS WOULD KEEP US IN NE FLOW
MON/TUE WITH DRY WEATHER ANTICIPATED...ALTHOUGH IT IS POSSIBLE ONE
OR TWO WEAK AREAS OF LOW PRESSURE COULD COME CLOSE ENOUGH TO BRING
AT LEAST SOME CLOUDINESS TO SE NEW ENGLAND.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT-TERM /THROUGH WEDNESDAY NIGHT/...HIGH CONFIDENCE.
VFR THROUGHOUT. SEA-BREEZES ALONG THE SHORES. ISOLATED
SHOWER POSSIBLE THIS EVENING MAINLY NE MA. BETTER CHANCE OF
SHOWERS/TSTMS WED AFTERNOON ESPECIALLY NORTHERN MA/SOUTHERN NH.
LOW PROB OF PATCHY FOG OVERNIGHT TONIGHT AND PERHAPS A LITTLE MORE
COVERAGE ON WED NIGHT.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.
OUTLOOK...THURSDAY THROUGH SUNDAY...
THURSDAY AND FRIDAY...MODERATE CONFIDENCE. IFR IN S COASTAL FOG
EARLY. ISOLATED SHOWERS/TSTMS WITH LOCAL IFR IN AFTERNOON.
SATURDAY...MODERATE CONFIDENCE. IFR IN S COASTAL FOG EARLY.
SCATTERED SHOWERS/TSTMS WITH LOCAL IFR IN AFTERNOON/EVENING.
SUNDAY...MODERATE CONFIDENCE. BECOMING VFR BY AFTERNOON.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
HIGH CONFIDENCE...
WINDS AND SEAS REMAIN BELOW SMALL CRAFT ADVISORY LEVELS THROUGH
WED NIGHT. HIGH PRES REMAINS OVER THE WATERS THROUGH WED. A LOW
PRES APPROACHES THE WATERS AND WEAKENS WED NIGHT. THERE IS A
CHANCE OF SOME REDUCED VSBYS IN FOG IN SOME SPOTS.
OUTLOOK...THURSDAY THROUGH SUNDAY...
THURSDAY AND FRIDAY...HIGH CONFIDENCE.
WEAK GRADIENT WILL RESULT IN SEA BREEZES ALONG E COAST WITH MORE
OF A SW FLOW ALONG S COAST WHERE 20KT GUSTS POSSIBLE. ISOLATED
THUNDERSTORMS POSSIBLE BOTH DAYS NEAR SHORE. EXPECT AREAS OF
NIGHTTIME AND EARLY MORNING FOG AROUND CAPE COD.
SATURDAY...MODERATE CONFIDENCE.
APPROACHING COLD FRONT WILL BRING INCREASING SW FLOW ON ALL WATERS
AS SEAS SLOWLY BUILD ON S COASTAL WATERS. STAYED BELOW WAVE WATCH
MODEL FORECAST OF 6-8 FT AS THIS MODEL IS TYPICALLY OVERDONE IN SW
FLOW DURING SUMMER...SHOULD BE MORE LIKE 4-5 FT AT MOST AND SCA
WILL PROBABLY BE NEEDED OFFSHORE.
AREAS OF NIGHTTIME AND EARLY MORNING FOG SHOULD PERSIST AROUND
CAPE COD.
SCATTERED THUNDERSTORMS POSSIBLE IN TWO ROUNDS...FIRST EARLY SAT
MORNING /PERHAPS NEAR S COAST?/ AND AGAIN TOWARD EVENING INTO SAT
NIGHT AS COLD FRONT PUSHES THROUGH NEW ENGLAND.
SUNDAY...MODERATE CONFIDENCE.
WINDS SHIFT TO NW AND DIMINISH AS COLD FRONT HEADS OFFSHORE BY
AFTERNOON. SEAS SLOWLY DIMINISH AS WELL BUT SHOULD REMAIN AT 5 OR
6 FT SE OF CAPE COD. SHOWERS/THUNDERSTORMS SHOULD LINGER
INITIALLY ON WATERS SE OF NANTUCKET BUT SHOULD BE WELL OFFSHORE BY
EARLY AFTERNOON.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...HEAT ADVISORY FROM 11 AM TO 7 PM EDT WEDNESDAY FOR CTZ002>004.
HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR CTZ002>004.
MA...HEAT ADVISORY FROM 11 AM TO 7 PM EDT WEDNESDAY FOR MAZ002>021-
026.
HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR MAZ010-011-013-
017-018.
NH...HEAT ADVISORY FROM 11 AM TO 7 PM EDT WEDNESDAY FOR NHZ011-012-
015.
RI...HEAT ADVISORY FROM 11 AM TO 7 PM EDT WEDNESDAY FOR RIZ001>007.
HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR RIZ001>004-006.
MARINE...NONE.
&&
$$
SYNOPSIS...JWD/GAF
NEAR TERM...GAF
SHORT TERM...GAF
LONG TERM...JWD
AVIATION...JWD/GAF
MARINE...JWD/GAF
AREA FORECAST DISCUSSION
NWS ALBANY NY
425 PM EDT TUE JUL 16 2013
.SYNOPSIS...
HOT AND HUMID CONDITIONS WILL CONTINUE THROUGH THE REST OF THE WORK
WEEK...AS AN EXPANSIVE AREA OF HIGH PRESSURE ALOFT ENCOMPASSES MUCH
OF THE EASTERN UNITED STATES. IT WILL CONTINUE TO BE MAINLY
DRY...UNTIL THURSDAY WHEN MULTIPLE FRONTAL BOUNDARIES WILL MOVE
ACROSS THE AREA RESULTING IN SCATTERED SHOWERS AND THUNDERSTORMS
INTO THE FIRST HALF OF THE WEEKEND. THE FINAL COLD FRONT LOOKS TO
MOVE THROUGH THE AREA ON SATURDAY BRINGING AND END TO THE HEAT WAVE.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AS OF 415 PM EDT...ANOTHER HOT AFTERNOON ACROSS THE AREA. ALBANY
AND POUGHKEEPSIE HAVE NOW REACHED 90 DEGREES FOR THE THIRD DAY IN
A ROW MAKING IT ANOTHER OFFICIAL HEAT WAVE...THE SECOND OF THIS
YEAR FOR BOTH LOCATIONS. A NORTHERLY AND OCCASIONALLY GUSTY BREEZE
HAS ALLOWED FOR SOME DEEPER MIXING WHICH HAS RESULTED IN DEWPOINTS
LOWER THAN PREVIOUS DAYS IN THE LOWER TO MID 60S ACROSS MUCH OF
THE AREA. THEREFORE WILL CANCEL THE HEAT ADVISORY FOR EASTERN
ULSTER...DUTCHESS AND SOUTHERN LITCHFIELD COUNTIES SINCE HEAT
INDEX VALUES WILL NOT REACH 100.
AN ISOLATED SHOWER OR TWO POPPED UP EARLIER IN THE SARATOGA REGION
BUT HAVE SINCE DISSIPATED. IT CONTINUES TO BE DIFFICULT TO BREAK THE
STRONG CAP AT 700 MB...SO ANY CONVECTION WILL BE BRIEF AND ISOLATED
AT BEST WITH VERY WEAK FORCING AS WELL. SPC MESOSCALE ANALYSIS FROM
THE RAP SHOWING SBCAPES MAINLY IN THE 1000-1500 J/KG RANGE ACROSS
THE AREA...BUT AGAIN THIS INSTABILITY IS NOT BEING REALIZED DUE TO
THE CAP. IF ANY ISOLATED SHOWERS/T-STORMS POP UP...THEY WILL
DIMINISH AFTER DARK WITH LOSS OF DAYTIME HEATING.
SOME PATCHY FOG WILL BE POSSIBLE AGAIN TONIGHT IN FAVORED RIVER
VALLEYS AND LOCATIONS NEAR BODIES OF WATER. MINIMUM TEMPERATURES
WILL BE ON THE WARM SIDE AGAIN TONIGHT...WITH LOWER TO MID 60S IN
THE HIGHER TERRAIN AND 65-70 ELSEWHERE.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
WEDNESDAY WILL BE ANOTHER HOT AND HUMID DAY ACROSS THE AREA...AS WE
WILL STILL REMAIN UNDER THE INFLUENCE OF THE EXPANSIVE UPPER LEVEL
RIDGE CENTERED OVER THE MIDWEST AND GREAT LAKES. TEMPERATURES SHOULD
BE SIMILAR TO TUESDAY...ALTHOUGH POSSIBLY A FEW DEGREES WARMER DUE
TO LOW LEVEL FLOW BECOMING MORE WESTERLY THAN NORTHERLY. SO
EXPECTING WIDESPREAD LOWER TO MID 90S FOR VALLEY LOCATIONS AND EVEN
UPPER 80S IN THE HIGHER TERRAIN. ALSO DEWPOINTS ARE EXPECTED TO BE
HIGHER THAN TUESDAY AS WELL...WITH HEAT INDEX VALUES AROUND OR
SLIGHTLY EXCEEDING 100 FOR EASTERN ULSTER...DUTCHESS AND SOUTHERN
LITCHFIELD COUNTIES. SO WILL ISSUE A HEAT ADVISORIES FOR THESE
AREAS. HEAT INDICES FORECAST TO BE IN THE MID TO UPPER 90S FOR THE
HUDSON...MOHAWK AND CT VALLEYS SO WILL MENTION POSSIBLE EVENTUAL
HEAT ADVISORY ISSUANCE IF VALUES INCREASE.
CHANCES FOR CONVECTION WILL AGAIN BE VERY LIMITED DUE TO LITTLE IN
THE WAY OF FORCING AND AN EXPECTED MID LEVEL CAP...AS OUR AREA WILL
STILL BE UNDER AN ANTI-CYCLONIC FLOW ALOFT ON THE NORTHEASTERN
PERIPHERY OF THE UPPER RIDGE. SBCAPE VALUES ARE FORECAST TO INCREASE
TO AROUND 1000-2000 J/KG WHICH COULD BE ENOUGH TO PRODUCE BRIEF
THUNDERSTORMS BUT AGAIN COVERAGE IS EXPECTED TO BE ISOLATED AT BEST.
IT WILL CONTINUE TO BE WARM AND MUGGY WEDNESDAY NIGHT WITH ANY
ISOLATED CONVECTION DIMINISHING AFTER DARK.
THURSDAY COULD BE THE FIRST DAY WHICH FEATURES A BETTER CHANCE FOR
GREATER COVERAGE OF CONVECTION...AS THE UPPER LEVEL RIDGE GETS
SUPPRESSED SOUTHWARD TO THE TENNESSEE VALLEY/MID ATLANTIC REGION.
THE RESULT FOR OUR AREA WILL BE HEIGHTS FLATTENING OUT ALOFT AS THE
FLOW PATTERNS CHANGES FROM ANTI-CYCLONIC TO ZONAL. THIS COULD ALLOW
FOR A DISTURBANCE OR TWO EMBEDDED IN THE INCREASING FLOW TO MOVE
THROUGH THE AREA AND PRODUCE SCATTERED CONVECTION MAINLY DURING THE
AFTERNOON AND EVENING. MODELS DEPICTING SBCAPE VALUES AROUND
1500-2500 J/KG WITH 0-6 KM BULK SHEAR MAGNITUDE AROUND 25-35 KT.
WITH LESS OF A CAP EXPECTED AND BETTER FORCING...THIS COULD ALLOW
FOR SOME ORGANIZED CLUSTERS OF CONVECTION TO DEVELOP. SOME OF THE
STORMS COULD BE STRONG DEPENDING ON THE EVENTUAL DEGREE OF
INSTABILITY. TEMPERATURES ON THURSDAY WILL ONLY AGAIN BE HOT WITH
LIKELY ADDITIONAL HEAT ADVISORIES LIKELY. WILL CONTINUE TO MENTION
IN HWO. THE ONLY NEGATING FACTOR TO REACHING SIMILAR TEMPS TO
WEDNESDAY WILL BE HOW MUCH CONVECTION/CLOUD COVER DEVELOPS DURING
THE AFTERNOON.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
BY FRIDAY THE PROCESS WILL BE UNDERWAY FOR THE UPPER RIDGE TO BUILD
MORE RAPIDLY WESTWARD WHILE NORTHERN STREAM UPPER TROUGHING BUILDS
SOUTH OUT OF CANADA INTO EASTERN NORTH AMERICA. THE ASSOCIATED COLD
FRONT IS EXPECTED TO DROP SOUTH IN STAGES EACH AFTERNOON AND EVENING
FRIDAY AND SATURDAY. THE LOW LEVEL THERMAL RIDGE SHOULD BE OVER THE
REGION FRIDAY AFTERNOON WITH PERHAPS THE HOTTEST TEMPERATURES OF
THIS PERIOD OF HEAT. HIGHS SHOULD BE SOLIDLY IN THE 90S...WITH SOME
MID TO UPPER 90S FROM THE CAPITAL DISTRICT AND POINTS SOUTH. HEAT
INDICES COULD EASILY EXCEED 100 IN MANY AREAS FRIDAY.
BASED ON THE MOVEMENT OF THE COLD FRONT...GENERALLY THE NORTHERN
HALF OF OUR FORECAST AREA SHOULD SEE THE BEST COVERAGE OF
THUNDERSTORMS THROUGH FRIDAY NIGHT...BUT ISOLATED THUNDERSTORMS ARE
STILL POSSIBLE IN SOUTHERN AREAS. ON SATURDAY...THE BOUNDARY LAYER
THERMAL GRADIENT WILL MAKE ITS MOVE THROUGH THE REGION AND THE COLD
FRONT SHOULD GET SOUTH OF THE FORECAST AREA BY SATURDAY NIGHT.
SO...HIGHS SATURDAY SHOULD BE IN THE 80S TO AROUND 90 AND THE BEST
COVERAGE OF THUNDERSTORMS SHOULD BE IN THE SOUTHERN HALF OF THE
FORECAST AREA...WITH DECREASING COVERAGE IN NORTHERN AREAS. BASED
ON THE UPPER DYNAMICS...UPPER AND LOW LEVEL JET STRUCTURE...
INSTABILITY...MOISTURE AND FRONTOGENESIS...SEVERE THUNDERSTORMS AND
LOCALIZED FLASH FLOODING ARE POSSIBLE FRIDAY AND SATURDAY.
BY SATURDAY NIGHT AND SUNDAY...ALL AREAS SHOULD DRY OUT AND HIGH
TEMPERATURES SUNDAY SHOULD BE AROUND NORMAL...WITH A NOTICEABLY
DRIER AIRMASS. HIGHS SUNDAY IN THE 70S TO LOWER 80S. THE COOLER AND
DRYER WEATHER...AROUND NORMAL TEMPERATURES SHOULD CONTINUE MONDAY
AND TUESDAY...WITH A LITTLE BIT OF WARMING PERHAPS BEGINNING ON
TUESDAY...DEPENDING ON THE TIMING OF ANOTHER UPPER IMPULSE THAT
COULD BEGIN ITS APPROACH TO OUR REGION FROM THE GREAT LAKES.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
VFR CONDITIONS WILL PREVAIL THROUGH THE REMAINDER OF THE AFTERNOON
WITH HIGH PRESSURE CONTINUING TO DOMINATE THE WEATHER ACROSS THE
REGION. WINDS WILL BE NORTHERLY AND LIGHT GENERALLY LESS THAN 10
KNOTS. A WEAK UPPER DISTURBANCE SLIDING OFF TO THE NORTH COMBINED
WITH DAYTIME HEATING MAY PROMOTE AN ISOLATED SHOWER/THUNDERSTORM
ACROSS NORTHERN AREAS SO HAVE INCLUDED VCSH AT KGFL WITH LITTLE
OPERATIONAL IMPACT EXPECTED. ALL OTHER TAF SITES WILL EXPERIENCE
SCATTERED TO BROKEN FAIR WEATHER CUMULUS DURING THE AFTERNOON HOURS
BETWEEN 5-7 KFT.
CLOUD COVER WILL DISSIPATE WITH LOSS OF DAYTIME HEATING TONIGHT WITH
WINDS BECOMING CALM. HAVE ONLY MENTIONED MVFR VISIBILITIES AT
KGFL...KPOU AND KPSF FOR HAZE/FOG WITH MOIST LOW-LEVELS. IFR MAY BE
POSSIBLE AT KGFL AND KPSF BUT CONFIDENCE REMAINS LOW AS WINDS WILL
BE SLOW TO DECOUPLE THROUGH THE OVERNIGHT...ALLOWING ENOUGH MOISTURE
TO MIX OUT DESPITE THE LOW DEWPOINT DEPRESSIONS.
ANY LINGERING PATCHY HAZE/FOG SHOULD QUICKLY DISSIPATE TOWARDS
SUNRISE TUESDAY GIVING WAY TO ANOTHER DAY OF SCATTERED-BROKEN FAIR
WEATHER CUMULUS AND LIGHT NORTHERLY WINDS AROUND 5-10 KNOTS.
WE ARE STARTING A NEW EXPERIMENTAL FORMAT FOR DISPLAYING THE
EXTENDED PORTION OF THE AVIATION DISCUSSION. THIS FORMAT BREAKS THE
EXTENDED PERIODS INTO 12-HOUR INCREMENTS. IT DOES NOT INCLUDE THE
POSSIBILITY OF IFR/VFR BUT THE POTENTIAL SENSIBLE WEATHER AND
"POTENTIAL" IMPACT THE WEATHER MIGHT CAUSE. WE HAVE OMITTED THE WORD
POTENTIAL TO KEEP THE VERBIAGE SHORTER.
TUESDAY NIGHT: LOW OPERATIONAL IMPACT. PATCHY FOG.
WEDNESDAY: MODERATE OPERATIONAL IMPACT. ISOLATED RAIN
SHOWERS...THUNDERSTORMS.
WEDNESDAY NIGHT: LOW OPERATIONAL IMPACT. NO SIGNIFICANT WEATHER.
THURSDAY: MODERATE OPERATIONAL IMPACT. SCATTERED RAIN
SHOWERS...THUNDERSTORMS.
THURSDAY NIGHT: MODERATE OPERATIONAL IMPACT. ISOLATED RAIN
SHOWERS...THUNDERSTORMS.
FRIDAY-SATURDAY: MODERATE OPERATIONAL IMPACT. SCATTERED RAIN
SHOWERS...THUNDERSTORMS.
SATURDAY NIGHT: MODERATE OPERATIONAL IMPACT. ISOLATED RAIN
SHOWERS...THUNDERSTORMS.
SUNDAY: NO OPERATIONAL IMPACT. NO SIGNIFICANT WEATHER.
&&
.FIRE WEATHER...
DUE TO SIGNIFICANT RAINFALL THAT HAS OCCURRED OVER THE PAST SEVERAL
WEEKS...THERE CONTINUES TO BE NO FIRE WEATHER RELATED CONCERNS.
DECENT RECOVERY IN LOW LEVEL MOISTURE IS EXPECTED EACH NIGHT WITH
DEW FORMATION. RELATIVE HUMIDITY VALUES WILL REMAIN ELEVATED DURING
THE AFTERNOON...ONLY DROPPING TO BETWEEN 40 AND 55 PERCENT.
EXPANSIVE HIGH PRESSURE AT THE SURFACE AND ALOFT...WILL CONTINUE TO
DOMINATE OVER THE EASTERN UNITED STATES RESULTING IN HOT AND HUMID
CONDITIONS. CHANCES FOR SHOWERS AND THUNDERSTORMS WILL INCREASE BY
THURSDAY AND CONTINUE THROUGH SATURDAY AS MULTIPLE FRONTAL
BOUNDARIES APPROACH AND EVENTUALLY MOVE THROUGH THE REGION.
&&
.HYDROLOGY...
OUTSIDE OF A STRAY SHOWER OR THUNDERSTORM...IT WILL BE MAINLY DRY
THROUGH WEDNESDAY WITH HOT AND HUMID CONDITIONS PERSISTING. THE
OVERALL TREND FOR MAIN STEM RIVERS WILL BE FOR FLOWS TO CONTINUE TO
DECREASE.
THE NEXT CHANCE OF MEASURABLE RAIN FOR MOST AREAS WILL BE THURSDAY
INTO SATURDAY WITH AT LEAST SCATTERED SHOWERS AND THUNDERSTORMS...AS
MULTIPLE FRONTAL BOUNDARIES APPROACH AND MOVE THROUGH THE REGION.
WITH HIGH MOISTURE CONTENT AND HUMIDITY LEVELS...HEAVY RAINFALL WILL
BE POSSIBLE WITH ANY THUNDERSTORMS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.CLIMATE...
TO ACCESS HEAT RELATED CLIMATE DATA INCLUDING HEAT WAVES...NUMBER
90+ DEGREES DAYS AND 100+ DEGREES DAYS...PLEASE VISIT
WWW.WEATHER.GOV/ALY/CLIMATE (ALL LOWER CASE) AND GO TO THE
RECORDS... EXTREMES... PAGE FOR ALBANY.
NUMBER OF 90+ DEGREE DAYS AND RECORD HIGHS...
ALBANY NY...
2013 MAY: 1 DAY
2013 JUNE: 4 DAYS
2013 JULY: 6 DAYS
2012: 13 DAYS
2011: 8 DAYS
2010: 14 DAYS
NORMAL: 10 DAYS
RECORD HIGHS: (DATE BACK TO 1874)
JULY 16: 97 DEGREES 1900
JULY 17: 99 DEGREES 1900
JULY 18: 100 DEGREES 1953
JULY 19: 97 DEGREES 1904
GLENS FALLS NY...
2013 MAY: 1 DAY
2013 JUNE: 2 DAYS
2013 JULY: 2 DAYS
2012: 8 DAYS
RECORD HIGHS: (DATE BACK TO 1949)
JULY 16: 95 DEGREES 1983
JULY 17: 99 DEGREES 1953
JULY 18: 97 DEGREES 1953
JULY 19: 95 DEGREES 1977
POUGHKEEPSIE NY...
2013 MAY: 3 DAY
2013 JUNE: 4 DAYS
2013 JULY: 7 DAYS
2012: 22 DAYS
RECORD HIGHS: (DATE BACK TO 1949)
JULY 16: 103 DEGREES 1995
JULY 17: 98 DEGREES 2006
JULY 18: 100 DEGREES 1991
JULY 19: 102 DEGREES 1991
BENNINGTON VT...
2013 MAY: NONE
2013 JUNE: NONE
2013 JULY: 1 DAY
2012: 7 DAYS
PITTSFIELD MA...
2013 MAY: NONE
2013 JUNE: NONE
2013 JULY: NONE
2012: 3 DAYS
&&
.EQUIPMENT...
KENX NATIONAL WEATHER SERVICE DOPPLER RADAR WILL BE UNAVAILABLE
THROUGH TUESDAY JULY 16 2013. TECHNICIANS CONTINUE TO TROUBLESHOOT
AT THIS TIME. WE EXPECT A FULL RETURN TO SERVICE LATER THIS
EVENING. WE APOLOGIZE FOR THE INCONVENIENCE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...HEAT ADVISORY FROM NOON TO 8 PM EDT WEDNESDAY FOR CTZ013.
NY...HEAT ADVISORY FROM NOON TO 8 PM EDT WEDNESDAY FOR NYZ064>066.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...JPV
NEAR TERM...JPV
SHORT TERM...JPV
LONG TERM...NAS
AVIATION...IRL
FIRE WEATHER...BGM/JPV
HYDROLOGY...BGM/JPV
CLIMATE...WFO ALY
EQUIPMENT...WFO ALY
AREA FORECAST DISCUSSION
NWS NEW YORK NY
400 PM EDT TUE JUL 16 2013
.SYNOPSIS...
HOT AND HUMID WEATHER WILL CONTINUE THROUGH THE END OF THE WEEK
WITH WEAK HIGH PRESSURE REMAINING ACROSS THE REGION THROUGH
WEDNESDAY NIGHT. A WEAK TROUGH OF LOW PRESSURE WILL DEVELOP ACROSS
THE AREA FOR THE REST OF THE WEEK. A COLD FRONT APPROACHES ON
SATURDAY AND MOVES SOUTH OF THE REGION ON SUNDAY AS HIGH PRESSURE
RETURNS FOR EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
WEAK HIGH PRESSURE ACROSS REGION WITH SHORTWAVE MOVING THROUGH NEW
ENGLAND THIS EVENING. UPPER LEVEL RIDGE STAYS ANCHORED TO OUR WEST.
HEAT AND HUMIDITY STILL IN PLACE WITH INCREASING MOISTURE CONTENT
WITHIN BOUNDARY LAYER. SEA BREEZE MORE SUPPRESSED TODAY SIMILAR TO
YESTERDAY. A SHORTWAVE MOVING ACROSS NEW ENGLAND THIS EVENING WILL
ALLOW FOR A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS AHEAD AND
ALONG IT. SOME MESO MODELS SUCH AS THE HRRR AND WRF NMM ARE
INDICATING THIS POSSIBILITY. OTHERWISE...DRY AND HUMID WEATHER
CONTINUES TONIGHT. LOWS WERE PREFERRED WITH WARMER
GUIDANCE...KEEPING TEMPERATURES IN THE 70S FOR MUCH OF THE AREA
TONIGHT AND UPPER 60S FOR INTERIOR AND RURAL SECTIONS.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
UPPER LEVEL RIDGE TO OUR WEST BEGINS TO SLOWLY FLATTEN WITH HIGH
PRESSURE AT THE SURFACE CONTINUING TO WEAKEN. A SURFACE TROUGH
DEVELOPS ACROSS THE AREA WEDNESDAY...WITH A BETTER SOUTHERLY FLOW
DEVELOPING ACROSS COASTAL SECTIONS. SO A BETTER CHANCE FOR SEA
BREEZES DURING THE AFTERNOON FOR AT LEAST IMMEDIATE COASTAL
SECTIONS. FLOW TURNS MORE SOUTHWEST WEDNESDAY NIGHT. POSSIBLE
SHOWER OR THUNDERSTORM ACROSS THE INTERIOR BUT NOT ENOUGH
CONFIDENCE TO INSERT IN FORECAST.
HIGHS WILL BE WELL INTO THE 90S WITH DEWPOINTS HIGHEST ALONG THE
URBAN CORRIDOR AND THE LOWER HUDSON VALLEY AS WELL AS INTERIOR
SOUTHERN CONNECTICUT. UPPER 80S TO LOWER 90S MAX TEMPS TOWARDS THE
COASTLINE IN COMBINATION WITH THE DEWPOINT WILL KEEP HEAT INDICES
AT LEAST A FEW DEGREES BELOW 100 DEGREES...THE CRITERION FOR HEAT
ADVISORY OUTSIDE OF NYC. HOWEVER...URBAN NORTHEAST NEW JERSEY AS
WELL AS NEW YORK CITY...THE LOWER HUDSON VALLEY...AND INTERIOR
SOUTHERN CONNECTICUT WILL BE APPROACHING 100 DEGREES FOR HEAT
INDICES SO HEAT ADVISORIES EXTENDED THROUGH EARLY WEDNESDAY
EVENING FOR THESE LOCATIONS. THERE IS SOME UNCERTAINTY DEPENDING
ON DAYTIME MIXING...WHICH IS FORECAST TO BE UP TO AROUND 850 MB
AGAIN. HOWEVER...MOISTURE IS FORECAST TO INCREASE RELATIVE TO
TODAY AND THIS MAKES SENSE DUE TO A GREATER SOUTHERLY SYNOPTIC
FLOW AND LESS SYNOPTIC NORTHERLY FLOW.
FOR WEDNESDAY NIGHT...SIMILAR TEMPS TO PREVIOUS NIGHT WITH DRY
WEATHER IN PLACE.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
DEEP LAYERED RIDGING WILL REMAIN OVER THE EASTERN CONUS THROUGH
FRIDAY. BY FRIDAY NIGHT...THERE IS EXCELLENT AGREEMENT AMONG THE
OPERATIONAL AND ENSEMBLE GUIDANCE OF THE RIDGE BREAKING DOWN AND
SHIFTING OFFSHORE AS UPPER LEVEL HEIGHTS BEGIN TO FALL AHEAD OF A
TROUGHING BUILDING INTO THE NE US. THIS TROUGH SENDS A COLD FRONT
THROUGH THE AREA SATURDAY/SATURDAY NIGHT.
HOT AND HUMID CONDITIONS WILL CONTINUE INTO SATURDAY. H85 TEMPS ARE
FORECAST TO RANGE FROM 18C TO 20C ON THURSDAY AND FRIDAY HELPING TO
MAKE THESE DAYS THE HOTTEST OF THE EXTENDED PERIOD. HEAT ADVISORY
HAS BEEN EXTENDED UNTIL 8PM THURSDAY FOR NEW YORK CITY. FOR LOWER
HUDSON VALLEY...NE NJ...AND INTERIOR CT...IT IS POSSIBLE HEAT
ADVISORY CRITERIA WILL BE MET THURSDAY BUT CONFIDENCE IS LOW AT THIS
TIME. ONE POSSIBLE CAVEAT IS HOW MUCH DRIER AIR MIXES DOWN. SIMILAR
CONDITIONS/CONCERNS EXIST ON FRIDAY SO WILL NEED TO CONTINUE TO
MONITOR TRENDS. WITH A SURFACE TROUGH AND HIGH AMOUNTS OF
INSTABILITY THURS AND FRI...A SHOWER OR THUNDERSTORM CANNOT BE RULED
OUT. THESE WILL LIKELY BE PULSE IN NATURE AS SHEAR IS MINIMAL.
COLD FRONT THEN APPROACHES SATURDAY BRINGING MUCH BETTER CHANCES FOR
SHOWERS AND STORMS. WITH HEIGHT FALLS OCCURRING ALOFT AND BETTER
SYNOPTIC LIFT...THE CHANCES FOR SHOWERS AND STORMS INCREASE.
INGREDIENTS MAY BE PRESENT TO PROMOTE SEVERE WEATHER SAT WITH THE
FRONT. PRIMARY THREATS AT THIS TIME APPEAR TO BE DAMAGING WINDS. ANY
STORM MAY ALSO PRODUCE HEAVY RAINFALL AS PWATS APPROACH 2 INCHES
SATURDAY.
THE FRONT SHOULD MOVE SOUTH OF THE AREA SUNDAY. HOWEVER...12Z GFS
DOES SLOW ITS PROGRESSION WITH A WAVE DEVELOPING ALONG IT. THE
LATEST 12Z ECMWF AND 12Z CMC DO NOT DEPICT THIS SCENARIO...BUT DO
HINT AT A SLIGHTLY SLOWER PROGRESSION SOUTHWARD.
THEREFORE...LINGERED CHANCE POPS MAINLY ACROSS SOUTHERN ZONES
SUNDAY.
A RETURN TO MORE SEASONABLE CONDITIONS EXPECTED FOR EARLY NEXT WEEK
AS HIGH PRESSURE BUILDS INTO THE AREA.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
HIGH PRES REMAINS OVER THE AREA.
GENERALLY NNE TO NNW FLOW AT 8-12 KT WITH OCNL GUSTS OF 16-18 KT
OVER THE TERMINALS. SEA BREEZE NOTICEABLE ON TJKF ALONG THE
IMMEDIATE SOUTH SHORE AND BARRIER ISLANDS. THINK THIS SEA BREEZE
WILL MAKE IT TO KJFK EARLY THIS EVENING...AROUND 22Z...AND ANOTHER
SEA BREEZE COULD IMPACT KGON BY 20Z.
WINDS BECOME VRB AT 5 KT OR LESS AFT 02Z...AND THEN NE TO SE WINDS
INCREASE TO 5-7 KT AFT 14Z WEDNESDAY.
VFR THROUGH THE TAF PERIOD.
...NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: LOW CONFIDENCE ON SEA BREEZE THIS AFTERNOON.
BEST TIMING WOULD BE AROUND 22Z...BUT TIMING COULD BE OFF BY AN
HOUR OR SO...IF THE SEA BREEZE DOES MOVE THROUGH THE TERMINAL.
HIGH CONFIDENCE WINDS TO THE RIGHT OF 310 TRUE OTHERWISE.
KLGA FCSTER COMMENTS: HIGH CONFIDENCE WINDS TO THE RIGHT OF 310
TRUE THROUGH THIS EVENING. VERY LOW CHANCE OF SEA BREEZE DURING
THE LATE AFTERNOON/EARLY EVENING HOURS.
KEWR FCSTER COMMENTS: HIGH CONFIDENCE WINDS TO THE RIGHT OF 310
TRUE THROUGH THIS EVENING. VERY LOW CHANCE OF SEA BREEZE DURING
THE LATE AFTERNOON/EARLY EVENING HOURS.
KTEB FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.
KHPN FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.
KISP FCSTER COMMENTS: HIGH CONFIDENCE WINDS TO THE RIGHT OF 310
TRUE THROUGH THIS AFTERNOON. LOW CHANCE SEA BREEZE IMPACTS
KISP...BUT IF IT DOES...IT WOULD OCCUR BETWEEN 20-22Z.
.OUTLOOK FOR 18Z WEDNESDAY THROUGH SUNDAY...
.WEDNESDAY-WEDNESDAY NIGHT...VFR.
.THURSDAY AND FRIDAY NIGHT...VFR. SLIGHT CHANCE SHRA/TSTM MAINLY
N AND W OF NYC DURING THE AFTERNOON/EVENING.
.SATURDAY...MAINLY VFR...BUT THE POTENTIAL LIES FOR WITH MVFR OR
LOWER CONDS IN STRONG TO SEVERE CONVECTION.
.SUNDAY...IMPROVING CONDS.
&&
.MARINE...
SUB SCA CONDITIONS ARE EXPECTED TO PREVAIL THROUGH WEDNESDAY NIGHT WITH
A WEAK PRESSURE GRADIENT IN PLACE.
A 15-20KT SW FLOW DEVELOPS OVER THE WATERS WITH GUSTS LIKELY
APPROACHING SCA LEVELS FRIDAY INTO SATURDAY. SEAS WILL ALSO BUILD TO
SCA LEVELS DURING THIS TIME. SUNDAY INTO MONDAY...WINDS SHOULD
REMAIN BELOW SCA LEVELS WITH MARGINAL SCA SEAS.
&&
.HYDROLOGY...
DRY CONDITIONS ARE EXPECTED THROUGH WEDNESDAY NIGHT.
A MOIST AIRMASS OVER THE AREA THURSDAY INTO FRIDAY BRINGS THE
POTENTIAL FOR HEAVY DOWNPOURS. HOWEVER...THUNDERSTORMS SHOULD REMAIN
ISOLATED LIMITING ANY FLASH FLOODING POTENTIAL. THE CHANCE FOR FLASH
FLOODING INCREASES ON SATURDAY WITH BETTER THUNDERSTORM COVERAGE AND
PRECIPITABLE WATERS INCREASING TO AROUND 2 INCHES.
&&
.CLIMATE...
TUESDAY JULY 16 2013 RECORD MAXIMUM TEMPERATURES
SITE RECORD FORECAST HIGH
BRIDGEPORT 94 (1983, 1952) 95
ISLIP 93 (1999) 95
LAGUARDIA 97 (1980) 97
KENNEDY 100 (1983) 95
CENTRAL PARK 99 (1980) 96
NEWARK 101 (1988) 97
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR CTZ005>012.
NY...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ067>071-078-
080-177-179.
HEAT ADVISORY UNTIL 8 PM EDT WEDNESDAY FOR NYZ072>075-176-178.
NJ...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NJZ004-006-
103>108.
MARINE...NONE.
&&
$$
SYNOPSIS...JM/DS
NEAR TERM...JM
SHORT TERM...JM
LONG TERM...DS
AVIATION...MPS
MARINE...JM/DS
HYDROLOGY...JM/DS
CLIMATE...DH/JM
AREA FORECAST DISCUSSION
NWS TAUNTON MA
357 PM EDT TUE JUL 16 2013
.SYNOPSIS...
HOT AND HUMID WEATHER WILL CONTINUE THIS WEEK WITH ONLY AN
ISOLATED SHOWER OR THUNDERSTORM THROUGH WEDNESDAY. CHANCES FOR
SHOWERS AND THUNDERSTORMS WILL INCREASE THURSDAY...FRIDAY AND
ESPECIALLY SATURDAY AS A COLD FRONT APPROACHES FROM THE GREAT
LAKES. RELIEF FROM THE HEAT AND HUMIDITY WILL ARRIVE ON SUNDAY
BEHIND A STRONG COLD FRONT AND LAST THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
235 PM UPDATE...
UPDATE...HAVE UPPED TEMPERATURES FOR THE ISLANDS FOR THE
REMAINDER OF THE LATE AFTERNOON/EVENING. HAVE NOW REACHED 86 AT
ACK, 89 AT MVY, AND 90 AT BID.
PREVIOUS DISCUSSION...
THE HOT WEATHER IS OCCURRING AGAIN...WITH 1 PM TEMPS ALREADY IN
THE LOW TO MID 90S ACROSS MUCH OF THE REGION. HEAT INDICES HAVE
TOPPED OUT AT 96 SO FAR AT BOSTON AND NEW BEDFORD. SO...NO CHANGE
TO THE HEAT ADVISORIES...ALTHOUGH MARGINAL. A FEW PLACES MAY HIT
100 LOCALLY FOR A COUPLE OF HOURS IN THE ADVISORY AREA.
A FEW SHOWERS HAVE POPPED IN SOUTHEASTERN MAINE...DRIFTING
SOUTHWARD TOWARD THE NEW HAMPSHIRE SEACOAST. THE 12Z NAM MODEL
SHOWS SHOWERS OR TSTM CHANCES BLOSSOMING ACROSS EASTERN MA TOWARD
EVENING. THINK THAT THIS IS OVERDONE. GFS HAS BACKED OFF OF ITS
PREVIOUS K INDEX FORECAST OF 32-34...MORE LIKE 28-30 NOW THIS
EVENING ALONG THE ROUTE 2 CORRIDOR. THUS CANNOT RULE OUT ISOLATED
TO WIDELY SCATTERED SHOWERS/TSTMS ANYWHERE ACROSS NORTHERN MA OR
ALONG THE SEA BREEZE IN EASTERN MA LATE THIS AFTERNOON...BUT ANY
CONVECTION SHOULD DISSIPATE AFTER SUNDOWN.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
TONIGHT...
DIURNAL DWPT RISE AND WARM TEMPERATURES WILL LEAD TO ANOTHER WARM
HUMID NIGHT TONIGHT WITH MANY LOCATIONS REMAINING IN THE 70S AND
UPPER 60S. ANY SHOWER/T-STORMS WILL DIMINISH RAPIDLY WITH THE LOSS
OF DIURNAL HEAT SUPPORT IN THE EVENING...AND ANY DIURNAL CU WILL
DIMINISH THANKS TO THE DRY SUBSIDENCE INVERSION GIVING WAY TO
PARTLY CLOUDY TO MOSTLY SKC BY THE EARLY MORNING HOURS.
WEDNESDAY...
SIMILAR TO TUESDAY IN THAT A WARM START AND PARTLY CLOUDY-MOSTLY
CLEAR CONDITIONS WILL GIVE WAY TO ANOTHER HOT DAY WITH HIGH TEMPS
APPROACHING THE MID 90S ONCE AGAIN THANKS TO A MODIFIED AIRMASS.
DWPTS MAY ONCE AGAIN BE CLOSE ENOUGH TO SUPPORT HEAT INDEX VALUES
NEAR 100F ACROSS THE REGION AS SOUNDINGS SUGGEST A SLIGHT
MOISTENING OF THE AIRMASS. WILL NEED TO MONITOR FOR ANOTHER HEAT
ADVISORY.
SLIGHTLY HIGHER CHANCE FOR AFTERNOON/EVENING SHOWERS AND
THUNDERSTORMS ON WED AS A WAVE OF LOW PRES PASSES THROUGH NRN NEW
ENGLAND PUSHING A RAPIDLY WEAKENING COLD FRONT INTO SRN NEW
ENGLAND BY THE AFTERNOON HOURS. HIGH PRES RIDGE STILL IN CONTROL
THOUGH WITH CAP AROUND H7 AND LOW /ALTHOUGH SLIGHTLY HIGHER THAN
TUE/ MID LVL LAPSE RATES. SB CAPE VALUES LOOK TO BE A BIT HIGHER
THANKS TO THE INCREASING MOISTURE WITHIN THE COLUMN...AVERAGING
ABOUT 1000-1500 J/KG. THEREFORE...WENT WITH MORE WIDESPREAD SLIGHT
CHANCE TO NEAR CHANCE POPS ACROSS THE REGIONS GIVEN THE POTENTIAL
FOR WEAK FORCING. WITH LITTLE TO NO SHEAR THOUGH...ANY STORMS THAT
DO DEVELOP WOULD BE UP AND DOWN RATHER RAPIDLY SINCE THEY WOULD
LIKELY BE UNABLE TO ORGANIZE.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
HEADLINES...
* HOT/HUMID THU INTO SAT WITH SCATTERED T-STORMS
* SEVERE STORMS POSSIBLE AHEAD OF A COLD FRONT SAT
* SEASONABLE AND DRY SUNDAY INTO THE BEGINNING OF NEXT WEEK
DETAILS...
NOT MUCH CHANGE IN OUR FORECAST THINKING FROM PREVIOUS SHIFTS.
MODELS REMAIN IN GOOD OVERALL AGREEMENT SHIFTING H5 HIGH SOUTH
AND WEST TOWARDS THE FOUR-CORNERS REGION ALLOWING FOR FALLING
HEIGHTS ACROSS NEW ENGLAND. THIS RESULTS IN THE RETURN OF THE
NORTHERN STREAM AS DOMINANT INFLUENCE AND SUBSEQUENTLY A MORE
ACTIVE PATTERN.
THURSDAY...
MODELS KEY ON LEE TROUGH BECOMING FOCUS FOR SCATTERED AFTERNOON
CONVECTION. SURFACE-BASED CAPES REACH 1500 J/KG WITH DECENT MID
LEVEL LAPSE RATES AROUND 6C/KM...BUT 0-6KM SHEAR IS MARGINAL AT
BEST. STILL NEED TO OVERCOME RATHER WARM MID LEVEL TEMPERATURES...
SO NOT CONFIDENT THAT STORM COVERAGE WILL BE ALL THAT GREAT. KEPT
CHANCE POPS FOR SCATTERED AFTERNOON THUNDERSTORMS WITH CONTINUED
MENTION OF HEAVY RAIN.
HIGH CAPE ENVIRONMENT FAVORS STRONG TO ISOLATED SEVERE STORMS...
BUT OVERALL SEVERE THREAT APPEARS TO BE LIMITED. PRECIPITABLE
WATER VALUES APPROACHING 2 INCHES...WHICH IS AROUND +2 STANDARD
DEVIATIONS...MEANS POTENTIAL FOR HEAVY RAINFALL AND ISOLATED
FLOODING IN STORMS.
HIGHS IN 90S AWAY FROM S COAST COMBINED WITH DEW POINTS IN LOWER
70S WILL ONCE AGAIN YIELD HEAT INDICES AROUND 100.
FRIDAY...
FLOW ALOFT BECOMES FLATTER WHICH SHOULD ALLOW ANY UPSTREAM
ACTIVITY TO PASS TO OUR N. HOWEVER WE REMAIN IN UNSTABLE AIRMASS
WITH BETTER CONVECTIVE POTENTIAL THAN THU. MODELS SHOW SURFACE
BASED CAPES 2000-3000 J/KG AND MID LEVEL LAPSE RATES OVER 6C/KM.
AXIS OF GREATEST 0-6KM SHEAR REMAINS ACROSS NORTHERN NEW ENGLAND
BUT SW NH AND NORTHERN MA ARE ON PERHIPHERY OF THIS AXIS WITH
VALUES OF 30-35KT. IN ADDITION WE ARE IN FAVORABLE RR QUAD OF
UPPER JET. ONLY LIMITING FACTOR APPEARS TO BE WARM MID LEVEL TEMPS
/+11C AT 700 MB/ BUT COLDER AIR ALOFT SHOULD BE ABLE TO
COMPENSATE.
EXPECT SCATTERED STORMS TO DEVELOP FRI AFTERNOON ACROSS MUCH OF
SOUTHERN NEW ENGLAND...ASIDE FROM IMMEDIATE S COAST WHICH WILL BE
MORE STABLE DUE TO SW FLOW. SEVERE POTENTIAL IS SOMEWHAT BETTER
THAN THU WITH BETTER POSSIBILITY OF DAMAGING WINDS DUE TO BOWING
SEGMENTS OR LINES. ALSO HAVE CONTINUED POTENTIAL FOR HEAVY
RAINFALL AND ISOLATED FLOODING.
INCREASING SW FLOW WILL RESULT IN WARMER DAY THAN THU. HIGHS
SHOULD TOP OUT IN LOW-MID 90S /GIVEN MODEL 2M TEMPERATURES/
COMBINED WITH DEW POINTS IN LOW-MID 70S SHOULD YIELD HEAT INDICES
OF 100-105. NOT CONFIDENT ENOUGH TO ISSUE EXCESSIVE HEAT WATCH BUT
WE MAY NEED TO DO SO IF THIS BECOMES MORE CERTAIN.
SATURDAY...
BEST POTENTIAL FOR ORGANIZED CONVECTION AS STRONG COLD FRONT
APPROACHES FROM GREAT LAKES. SOME QUESTION AS TO WHETHER OR NOT
ANY EARLY MORNING CONVECTION WILL INHIBIT SIGNIFICANT
DESTABILIZATION DURING AFTERNOON. PATTERN SEEMS TO FAVOR AT LEAST
MORNING SHOWERS/STORMS NEAR S COAST...THEN WE SEE A BREAK BEFORE
ADDITIONAL STORMS FIRE DURING AFTERNOON AND EVENING.
NO REAL CHANGE IN THINKING FROM SPC DAY 4 OUTLOOK AND PREVIOUS
DISCUSSION. EXPECTED INSTABILITY COUPLED WITH BULK SOUTHWESTERLY
UNI-DIRECTIONAL SHEAR AROUND 35 KTS FAVORS MULTICELLS AND LINE
ECHO WAVE PATTERNS WITH DAMAGING WINDS MAIN THREAT. ALSO NEED TO
BE AWARE OF CONTINUED FLASH FLOOD POTENTIAL WITH PRECIPITABLE
WATER VALUES NEAR 2 INCHES.
SUNDAY INTO THE EARLY WEEK...
COLD FRONT WILL HEAD OFFSHORE SUN MORNING...PERHAPS NOT UNTIL SUN
AFTERNOON ON CAPE COD. COOLER AND DRIER AIR WILL FOLLOW ON NW
WINDS LATER SUN. FRONT MAY BECOME STATIONARY AS IT RUNS UP INTO
RIDGING OVER WESTERN ATLANTIC. THIS WOULD KEEP US IN NE FLOW
MON/TUE WITH DRY WEATHER ANTICIPATED...ALTHOUGH IT IS POSSIBLE ONE
OR TWO WEAK AREAS OF LOW PRESSURE COULD COME CLOSE ENOUGH TO BRING
AT LEAST SOME CLOUDINESS TO SE NEW ENGLAND.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT-TERM /THROUGH WEDNESDAY/...HIGH CONFIDENCE.
VFR THROUGHOUT. SEA-BREEZES ALONG THE SHORES. ISOLATED
SHOWER/T-STORM POSSIBLE PARTICULARLY SRN NH AND NORTHEAST MA...
AND PERHAPS ALONG THE SEA BREEZE FRONT IN EASTERN MA. VERY LOW
CONFIDENCE IN MORE FOG WITH MVFR VSBYS TONIGHT. OTHERWISE VFR
CONTINUES.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.
OUTLOOK...THURSDAY THROUGH SUNDAY...
THURSDAY AND FRIDAY...MODERATE CONFIDENCE. IFR IN S COASTAL FOG
EARLY. ISOLATED SHOWERS/TSTMS WITH LOCAL IFR IN AFTERNOON.
SATURDAY...MODERATE CONFIDENCE. IFR IN S COASTAL FOG EARLY.
SCATTERED SHOWERS/TSTMS WITH LOCAL IFR IN AFTERNOON/EVENING.
SUNDAY...MODERATE CONFIDENCE. BECOMING VFR BY AFTERNOON.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
HIGH CONFIDENCE...
WINDS AND SEAS REMAIN BELOW SMALL CRAFT ADVISORY LEVELS THROUGH
THE PERIOD AS HIGH PRES REMAINS IN CONTROL. THERE IS THE CHANCE
FOR SOME REDUCED VSBYS IN FOG IN SOME SPOTS.
OUTLOOK...THURSDAY THROUGH SUNDAY...
THURSDAY AND FRIDAY...HIGH CONFIDENCE.
WEAK GRADIENT WILL RESULT IN SEA BREEZES ALONG E COAST WITH MORE
OF A SW FLOW ALONG S COAST WHERE 20KT GUSTS POSSIBLE. ISOLATED
THUNDERSTORMS POSSIBLE BOTH DAYS NEAR SHORE. EXPECT AREAS OF
NIGHTTIME AND EARLY MORNING FOG AROUND CAPE COD.
SATURDAY...MODERATE CONFIDENCE.
APPROACHING COLD FRONT WILL BRING INCREASING SW FLOW ON ALL WATERS
AS SEAS SLOWLY BUILD ON S COASTAL WATERS. STAYED BELOW WAVE WATCH
MODEL FORECAST OF 6-8 FT AS THIS MODEL IS TYPICALLY OVERDONE IN SW
FLOW DURING SUMMER...SHOULD BE MORE LIKE 4-5 FT AT MOST AND SCA
WILL PROBABLY BE NEEDED OFFSHORE.
AREAS OF NIGHTTIME AND EARLY MORNING FOG SHOULD PERSIST AROUND
CAPE COD.
SCATTERED THUNDERSTORMS POSSIBLE IN TWO ROUNDS...FIRST EARLY SAT
MORNING /PERHAPS NEAR S COAST?/ AND AGAIN TOWARD EVENING INTO SAT
NIGHT AS COLD FRONT PUSHES THROUGH NEW ENGLAND.
SUNDAY...MODERATE CONFIDENCE.
WINDS SHIFT TO NW AND DIMINISH AS COLD FRONT HEADS OFFSHORE BY
AFTERNOON. SEAS SLOWLY DIMINISH AS WELL BUT SHOULD REMAIN AT 5 OR
6 FT SE OF CAPE COD. SHOWERS/THUNDERSTORMS SHOULD LINGER
INITIALLY ON WATERS SE OF NANTUCKET BUT SHOULD BE WELL OFFSHORE BY
EARLY AFTERNOON.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR CTZ002>004.
MA...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR MAZ010-011-013-
017-018.
NH...NONE.
RI...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR RIZ001>004-006.
MARINE...NONE.
&&
$$
SYNOPSIS...DOODY/SIPPRELL
NEAR TERM...GAF
SHORT TERM...DOODY
LONG TERM...JWD
AVIATION...JWD/GAF
MARINE...JWD/GAF
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
1000 PM EDT WED JUL 17 2013
.DISCUSSION...
AN EARLY EVENING SURGE OF CONVECTION OVER THE ATLC PUSHED ONSHORE
BTWN MELBOURNE AND STUART...GENERATING LCL RAINFALL ON THE ORDER OF
ONE INCH OVER SE BREVARD/NE INDIAN RIVER COUNTIES. THE BULK OF THAT
PRECIP BAND HAS LARGELY DISSIPATED OR MOVED OUT OF THE CWA.
LATEST RUC ANALYSIS SHOWS DEEP MOISTURE ACRS MUCH OF THE CWA WITH
MEAN RH VALUES AOA 80PCT THRU THE H100-H50 LYR. ANALYSIS ALSO SHOWS
A NOTEWORTHY H85-H50 VORT AXIS EXTENDING FROM FORT MYERS ACRS THE
NRN BAHAMAS. WHILE THIS MID LVL DISTURBANCE IS COLOCATED WITH AN
AREA OF SINKING OMEGA AIR...THE PENINSULA IS ON THE ASCENDING OF AN
H30-H20 LOW CENTERED OVER THE NE GOMEX...RESULTING IN AN AREA OF
ENHANCED UPR LVL DIVERGENCE. THE AXIS OF A WEAK H100-H85 ERLY WAVE
EXTENDING FROM THE YUCATAN PENINSULA TO THE SW FL PENINSULA COULD
ADD SOME LOW LVL INSTABILITY OVERNIGHT AS WELL.
THE INITIAL PRECIP SURGE BURNED OFF SOME OF THE AVAILABLE ENERGY...
BUT THE REMAINING FACTORS DO SUPPORT CARRYING POPS IN THE FCST THRU
THE OVERNIGHT PD. EVENING SOUNDINGS AND LATEST WIND DATA FROM THE
THE USAF 915MHZ PROFILER AND THE KMLB WSR-88D SHOW A SOLID 15-20KT
E/SE FLOW THRU 10KFT...SUGGESTING NOCTURNAL CONVECTION WOULD MAKE IT
WELL INTO THE INTERIOR BEFORE DISSIPATING.
WILL CAP OVERNIGHT POPS AT 40PCT BUT WILL EXPAND PRECIP COVERAGE TO
THE INTERIOR FOR POINTS S OF THE I-4 CORRIDOR. THUNDER CHANCES ALONG
THE COAST S OF MELBOURNE LOOK REASONABLE.
&&
.AVIATION...
THRU 18/14Z...PREVAILING VFR ALL SITES WITH CIGS AOA FL100...
KDAB-KVRB BRIEF IFR VSBYS/MVFR CIGS IN ISOLD COASTAL SHRAS...
KMLB-KSUA CHC IFR TSRAS. BTWN 18/14Z-18/18Z...PREVAILING VFR ALL
SITES...ISOLD MVFR SHRAS/IFR TSRAS. AFT 18/18Z...S OF KMLB-KISM
LIKELY IFR TSRAS...N OF KMLB-KISM SCT IFR TSRAS.
&&
.MARINE...
WEAK PGRAD ACRS THE LCL ATLC WILL MAINTAIN A LIGHT TO GENTLE E/SE
BREEZE OVERNIGHT...SEAS 2-3FT. CHANCE OF MARINE TSRAS OVERNIGHT S OF
CAPE CANAVERAL CAPABLE OF GENERATING WIND GUSTS BTWN 35-40KTS.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
FORECAST....BRAGAW
IMPACT WX...CRISTALDI
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
945 PM EDT WED JUL 17 2013
.UPDATE...
01Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS THAT MUCH OF THE CONUS IS
COVERED BY A LARGE AREA OF UPPER RIDGING. UPPER LOW THAT HAS BEEN
RETROGRADING ACROSS THE SOUTHERN TIER OF THE COUNTY THE PAST SEVERAL
DAYS IS NOW WEAKENING/DECAYING AS IT MOVES SOUTH OF THE 4-CORNERS
REGION. WEAK UPPER LOW/CYCLONIC EDDY HAS BEEN SPINNING NEAR OUR
LOCAL AREA AS WELL. THIS FEATURE WILL CONTINUE WESTWARD AND WEAKEN A
BIT DURING THE NEXT 24 HOURS...HOWEVER STILL LOOKS LIKE AT LEAST
SOME LINGERING ASSOCIATED CYCLONIC FLOW OVER THE PENINSULA WILL ONCE
AGAIN AID THE DIURNAL CONVECTION ON THURSDAY.
AT THE SURFACE...SYNOPTIC EASTERLY FLOW IS IN PLACE BETWEEN A LARGE
AREA OF CONTINENTAL HIGH PRESSURE CENTERED NEAR KANSAS CITY AND A
WEAK INVERTED TROUGH OVER THE SOUTH-CENTRAL/SE GULF OF MEXICO. SOME
INDICATIONS THAT THIS FLOW WILL WEAKEN ON THURSDAY AS THE INVERTED
TROUGH EXPANDS NORTH AND EAST TOWARD THE FLORIDA WEST COAST. THIS
LOWER LEVEL FOCUS MAY FURTHER ENHANCE THE CONVECTIVE POTENTIAL FROM
PASCO/HERNANDO COUNTIES...SOUTHWARD ACROSS THE I-4 CORRIDOR AND DOWN
TO FORT MYERS.
BUSY DAY IN TERMS OF CONVECTION CONTINUES TO SETTLE DOWN WITH THE
LOSS OF DIURNAL HEATING AND WIDESPREAD RELEASE OF INSTABILITY DURING
THE AFTERNOON/EARLY EVENING. SOME OF THE STORMS WERE FAIRLY GUSTY IN
NATURE INCLUDE 2 STORMS IN THE PINELLAS/HILLSBOROUGH COUNTY AREA
WHICH SHOWED 65-70+ KNOT LOW LEVEL WINDS PER DOPPLER RADAR. THOSE
ARE IMPRESSIVE VALUES. FOR THE REST OF THE EVENING/OVERNIGHT. JUST A
FEW SCT SHOWERS EXPECTED AS THE CYCLONIC FLOW ALOFT COULD SUPPORT A
FEW RAINDROPS AT JUST ABOUT ANY TIME...BUT OVERALL CONDITIONS WILL
BE DRY OVER THE LAND MASS WITH MORE IN THE WAY OF SHOWERS OFFSHORE.
ON THURSDAY...GENERALLY QUIET TO START THE MORNING FOR OUR
ZONES...AND THEN THE CONVECTION SHOULD START TO GET ITS ACT TOGETHER
MIDDAY/EARLY AFTERNOON. STORM MOTION ON THURSDAY IS MORE LIKELY TO
BE FROM THE SOUTHEAST OR EVEN SOUTH TO NORTH FOR THE SOUTHERN HALF
OF THE PENINSULA. AS MENTIONED ABOVE...SOME LINGERING CYCLONIC FLOW
ALOFT COMBINED WITH SURFACE FOCUS FROM WEAK SURFACE TROUGH AND
POTENTIAL SEA-BREEZES MAY LEAD TO A RATHER ACTIVE SECOND HALF OF THE
DAY IN TERMS OF THUNDERSTORMS. LOCAL HI-RESOLUTION CONVECTION
ALLOWING MODELS ARE ALL HINTING AT AN ACTIVE DAY...AND SOME CONCERN
WITH THE STRENGTH OF THE CONVECTION BEING SIMULATED. LAST 2 WRF-ARW
RUNS HAVE SHOWN QUITE A FEW UPDRAFTS IN EXCESS OF 20 M/S WITHIN THE
MODEL SIMULATIONS...WHICH HAS BEEN WELL CORRELATED WITH
STRONG/SEVERE POTENTIAL. WILL HAVE TO SEE HOW THAT WORKS OUT. IF
THERE IS A DEFINED SEA-BREEZE WITH INLAND PENETRATION...IT IS LIKELY
TO BE DOWN ALONG THE SUNCOAST...MAINLY SOUTH OF SARASOTA. FOR THESE
AREA...IT IS POSSIBLE THAT THE SYNOPTIC FLOW AND SEA-BREEZE COULD
HELP CLEAR OUT SOME OF THE CONVECTION NEAR THE BEACHES BY LATE
AFTERNOON. HOWEVER...THE PATTERN IS JUST TOO WEAK TO DRAW SHARP
SPATIAL OR TEMPORAL GRADIENTS IN THE RAIN CHANCES JUST YET...AND
WILL BE MORE BROAD WITH A LIKELY POPS FOR STORMS AFTER 16-17Z TO
THE SOUTH OF HERNANDO COUNTY...AND CHANCE POPS FURTHER NORTH UP THE
NATURE COAST. ENJOY THE REST OF YOUR EVENING.
&&
.AVIATION...
AFTERNOON TSRA HAVE PUSHED OFFSHORE AND ARE WINDING DOWN. SOME SHRA
OVER THE INTERIOR NOT EXPECTED TO REACH THE COAST BUT MAY BRUSH LAL
WHICH HAS VCSH THIS EVENING. THERE COULD BE SOME LOW STRATUS TOWARD
MORNING...WILL LIMIT TO JUST A SCT LAYER FOR NOW. ANTICIPATE ANOTHER
ROUND OF SCT-NMRS TSRA WITH MVFR/LCL IFR AFT 18Z.
&&
.MARINE...
WINDS AND SEAS WILL REMAIN BELOW ADVISORY OR CAUTIONARY CRITERIA
THROUGH THE NEXT FEW DAYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 74 88 75 87 / 30 60 40 50
FMY 72 89 73 90 / 20 60 30 40
GIF 73 91 73 90 / 60 60 30 50
SRQ 74 88 74 88 / 30 60 40 50
BKV 70 89 71 90 / 30 50 40 50
SPG 75 88 77 88 / 30 60 40 50
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE...MROCZKA
AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
610 PM EDT TUE JUL 16 2013
.UPDATE (REST OF TONIGHT AND WEDNESDAY)...
22Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS AN UPPER LEVEL PATTERN
DOMINATED BY AN IMMENSE UPPER RIDGE CENTERED OVER THE MIDWEST
STATES. VERY IMPRESSIVE H5 HEIGHTS OF UP TO 600DM CONTINUE TO BE
SEEN UNDER THE CENTER OF THIS RIDGE. UNUSUALLY BEHAVED UPPER LOW FOR
JULY NOW OVER NEW MEXICO HAS BEEN RETROGRADING WESTWARD THE PAST FEW
DAYS AROUND THE SOUTHERN PERIPHERY OF THE RIDGE. OTHER FEATURE OF
NOTE FOR OUR FORECAST IS A WEAK UPPER LOW/DISTURBANCE SPINNING OVER
THE SOUTHERN HALF OF THE FL PENINSULA/FL STRAITS. THIS CYCLONIC EDDY
IS FORECAST TO VERY SLOWLY MOVE WESTWARD INTO THE SOUTHEAST GULF OF
MEXICO ON WEDNESDAY.
AT THE SURFACE...EASTERLY FLOW DOMINATES THE REGION ON THE FAR
SOUTHERN PERIPHERY OF 1025MB HIGH PRESSURE CENTERED NEAR
INDIANAPOLIS THIS EVENING. THIS EASTERLY FLOW WILL LINGER THROUGH AT
LEAST WEDNESDAY BEFORE THE SUBTROPICAL RIDGE AXIS REBUILDS OVER THE
PENINSULA AND WEAKENS THE GRADIENT.
LOCAL WEATHER THE PAST SEVERAL HOURS HAS BEEN INFLUENCED HIGHLY BY
AN IMPULSE...LIKELY GRAVITY WAVE THAT INITIATED FROM CONVECTION DOWN
OVER SE FLORIDA EARLIER TODAY. THIS GRAVITY WAVE HAS BEEN
PROPAGATING NORTHWARD THROUGH THE MID AFTERNOON AND EARLY EVENING
HOURS ENHANCING THE CONVECTION AS IT WENT. THIS FEATURE IS VERY
EVIDENT IF LOOKING AT A FAST PACED AND LONG DURATION RADAR LOOP OVER
THE PAST 6 OR SO HOURS. WHAT IS LEFT OF THIS IMPULSE IS NOW UP OVER
THE NORTHERN NATURE COAST AND SHOULD EXIT NORTH OF LEVY COUNTY SOON.
IN ITS WAKE...CONDITIONS QUIET DOWN QUICKLY AND HAVE SIGNIFICANTLY
DECREASED POPS GOING INTO THE MIDDLE/LATER EVENING HOURS FOR ALL
ZONES SOUTH OF LEVY COUNTY. LEFT A 20% RAIN CHANCE IN FOR MOST AREAS
THROUGH 03Z TO ACCOUNT FOR ANY STRAY SHOWERS THAT CAN DEVELOP AT
JUST ABOUT ANY TIME UNDERNEATH THE CYCLONIC FLOW OF THE MORE BROAD
UPPER LOW. HOWEVER...LOOKS LIKE MUCH OF THE RAINFALL FOR THE DAY HAS
ENDED FOR AREAS SOUTH OF CRYSTAL RIVER...AND WILL BE ENDING FOR
SUMTER/CITRUS/LEVY COUNTY IN THE NEXT COUPLE OF HOURS AS WELL.
THE REMAINDER OF THE OVERNIGHT LOOKS RATHER QUIET...WITH THE BEST
CHANCE OF LAND BASED SHOWERS AFTER 03Z BEING DOWN TOWARD THE
CHARLOTTE/LEE COUNTIES (BUT ONLY 20-30%).
FOR WEDNESDAY...
A GENERAL CYCLONIC FLOW ALOFT WILL STILL BE PRESENT ASSOCIATED WITH
THE WEAK UPPER LOW ALONG/JUST OFF THE SW FL COAST. BEST CHANCES FOR
DEVELOPING DIURNAL SHOWERS/STORMS (50-60%) SHOULD EXIST SOUTH OF
I-4...COINCIDENT WITH THE DEEPER MOISTURE FIELDS ADVERTISED BY THE
GFS/ECMWF. AREAS FURTHER NORTH SHOULD STILL SEE SOME FAST MOVING
SHOWERS PROGRESSING FROM EAST TO WEST...HOWEVER COVERAGE COULD BE
DESCRIBED AS MORE SCT (30-40%) IN NATURE.
&&
.AVIATION...
AFTERNOON SHRA AND TSRA HAVE PUSHED OFFSHORE AND WEAKENED. VFR
CONDITIONS OVERNIGHT THROUGH WED MORNING. SCT-NMRS TSRA IN THE
AFTERNOON WITH MVFR/LCL IFR POSSIBLE. LIGHT NE WINDS
OVERNIGHT...EASTERLY AND SLIGHT STRONGER WED.
&&
.MARINE...
EXPECT EXERCISE CAUTION CRITERIA FOR THE OFFSHORE WATERS
TONIGHT...WITH WINDS OF 15 TO 20 KNOTS EXPECTED. SEAS WILL BE UP
TO 4 FEET. OTHERWISE BOTH WINDS AND SEAS ARE FORECAST TO REMAIN
BELOW ADVISORY AND CAUTIONARY LEVELS.
&&
.FIRE WEATHER...
NO CONCERNS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 75 90 74 88 / 20 50 30 60
FMY 73 88 72 88 / 20 60 30 60
GIF 72 90 73 91 / 20 50 20 50
SRQ 74 91 73 87 / 20 50 30 60
BKV 71 91 70 89 / 20 40 20 50
SPG 78 90 77 87 / 20 40 30 60
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE...MROCZKA
AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
1105 PM EDT WED JUL 17 2013
.SHORT TERM /REMAINDER OF TONIGHT/...
EASTERLY FLOW CONTINUES OVER THE AREA. ENOUGH INSTABILITY REMAIN FOR
CONVECTION TO CONTINUE FIRING OVER THE AREA. THOUGH MUCH OF THE
THUNDERSTORM ACTIVITY OVER NORTH GEORGIA HAS DIMINISHED TO
SHOWERS...A FEW EMBEDDED THUNDERSTORMS CONTINUE TO DEVELOP. THE
SOUTHERN PORTION OF THE FORECAST AREA HAS BECOME MORE ACTIVE WITH
THUNDERSTORM DEVELOPMENT...MAINLY ALONG SOME OF THE BOUNDARIES FROM
PREVIOUS STORMS TO THE NORTH. THE ANTICIPATION IS FOR THESE STORMS
TO ALL WEAKEN AND DIMINISH OVER THE NEXT FEW HOURS...AND MOSTLY
CLOUDY CLOUDY SKIES TO CONTINUE INTO MORNING.
.PREVIOUS DISCUSSION...ISSUED AT 330 PM...
.SHORT TERM/TONIGHT THROUGH THURSDAY NIGHT/...
CURRENT SATELLITE LOOP SHOWS MAIN EASTERN WAVE MOVING INTO NE GA AT
THE MOMENT. THE CURRENT RADAR LOP SHOWS SHOWERS AND ISOLATED
THUNDERSTORMS POPPING UP ACROSS NE GA WHICH IS DEFINITELY BEING
GENERATED BY THIS WAVE. THE MAIN ENERGY FROM THIS WAVE IS EXPECTED
TO STAY ACROSS NORTH GA BUT BOTH OUR LOCAL WRF AND THE HRRR SHOW A
BIT MORE DIURNALLY DRIVEN POP UP SHRA/TSRA ACROSS THE STATE THROUGH
02-04Z TONIGHT. THE SURFACE TO UPPER LEVEL RIDGE KEEPS OUR AREA IN
MOIST EASTERLY FLOW THROUGH THE SHORT TERM. THE MODELS ARE SHOWING
ANOTHER WEAKER WAVE MOVING ACROSS THE AREA THU IN THIS EASTERLY
FLOW. WITH THIS IN MIND SHOULD SEE ANOTHER DIURNALLY DRIVEN
CONVECTIVE DAY THU. THERE IS VERY LITTLE SHEAR IN THIS ATMOSPHERE
BUT THE CAPES AND LIS BOTH PEAK BETWEEN 18Z AND 00Z THIS AFTERNOON
AND THURSDAY. TODAY SHOULD BE THE WARMEST DAY THIS WEEK WITH RISING
THICKNESSES TODAY HOWEVER PRECIP/CLOUDS MAY OFFSET THE WARMING A
LITTLE. H5 HEIGHTS WILL BE DROPPING THURSDAY YIELDING A SLIGHTLY
COOLER TEMPS. STAYING CLOSE TO CURRENT FORECAST TEMPS AS THEY STILL
LOOKS GOOD.
01
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
NO SIG CHANGES TO THE EXTENDED. ONLY CHANGE WERE TO THE POPS ON
SUNDAY WHERE OUR NEIGHBORS AND GUIDANCE SUGGESTS A LIKELY CHANCE
OF POPS. DECIDED TO GO WITH THAT FOR SUNDAY AFTERNOON. OTHERWISE
UPDATED THE DEWPOINTS...WINDS AND TEMPERATURES WITH NEW GUIDANCE.
HAVE ATTACHED PREVIOUS DISCUSSION FOR BREVITY.
ARG
&&
.PREV DISCUSSION... /ISSUED 730 AM EDT WED JUL 17 2013/
LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
/ISSUED AT 355 AM EDT WED JUL 17 2013/
A TRANSITION TAKES PLACE THIS PERIOD FROM EAST FLOW ALOFT TO
WESTERLY FLOW WITH A UPPER TROUGH DEVELOPING OVER THE EASTERN
STATES. GFS AND EUROPEAN ARE SIMILAR WITH THIS CHANGE UNTIL THE
MONDAY TO WEDNESDAY TIME FRAME WHEN THE EUROPEAN MOVES THE TROUGH
TO THE WESTERN ATLANTIC AND THE GFS KEEPS THE UPPER TROUGH OVER THE
OH/TN VALLEYS AS A STRONGER UPPER SHORT WAVE MOVES OVER THE MID U.S.
PLENTY OF MOISTURE AND INSTABILITY THIS PERIOD FOR AT LEAST
SCATTERED SHOWERS AND THUNDERSTORMS FOR MOST AREAS...TENDING TO
MAXIMIZE IN THE AFTERNOON AND EVENING HOURS. DEEPER MOISTURE MOVES
ACROSS THE AREA WITH THE INITIAL ONSET OF THE UPPER TROUGH
SUNDAY/MONDAY AS A FRONT BECOMES STATIONARY JUST N OF GA AND A
SURFACE TROUGH SETS UP FROM THE CAROLINAS INTO GA. TEMPERATURES
GENERALLY CLOSE TO NORMAL EXCEPT HIGH TEMPERATURES WILL RUN
SLIGHTLY BELOW NORMAL FROM SATURDAY ON.
BDL
AVIATION...
00Z UPDATE...
TSTMS CONTINUE TO PUSH TO THE WEST...BUT SHOWING SIGNS OF
WEAKENING...AND PLENTY OF RAINFALL OVER MUCH OF AREA. CIGS MAINLY
VFR...BUT SOME MVFR CIGS IN TSRA/RA UNTIL 02Z. EXPECTING CIGS
TO REMAIN VFR THROUGHOUT PERIOD. VSBYS MAINLY VFR...BUT AGAIN SOME
MVFR VSBYS IN TSRA/RA...AND WEAKENING TSTMS UNTIL 02Z. WITH
WIDESPREAD RAINFALL...UNCERTAIN AS TO WHETHER MVFR CONDS WILL
DEVELOP FROM SUCH A MOIST AIRMASS. MODELS NOT SHOWING ANY CHANGE IN
PATTERN...HENCE WOULD EXPECT SIMILAR OCCURRENCES TOMORROW FOR MORE
SCATTERED AFTERNOON STORM DEVELOPMENT ACROSS AREA.
//ATL CONFIDENCE...00Z UPDATE...
MODERATE TO LOW CONFIDENCE ON CIG AND VSBY. MODERATE ON WINDS.
37
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 71 92 71 90 / 40 30 30 40
ATLANTA 74 91 73 88 / 40 30 30 50
BLAIRSVILLE 69 88 68 84 / 40 50 30 50
CARTERSVILLE 70 91 71 89 / 40 40 30 50
COLUMBUS 73 94 73 90 / 20 30 30 50
GAINESVILLE 73 90 73 88 / 40 40 30 50
MACON 71 92 71 90 / 30 30 20 40
ROME 71 92 71 90 / 40 40 30 50
PEACHTREE CITY 71 91 70 89 / 40 30 30 50
VIDALIA 72 93 72 89 / 20 30 20 40
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...01
LONG TERM....ARG
AVIATION...37
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
815 PM EDT WED JUL 17 2013
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
CURRENT SATELLITE LOOP SHOWS MAIN EASTERN WAVE MOVING INTO NE GA AT
THE MOMENT. THE CURRENT RADAR LOP SHOWS SHOWERS AND ISOLATED
THUNDERSTORMS POPPING UP ACROSS NE GA WHICH IS DEFINITELY BEING
GENERATED BY THIS WAVE. THE MAIN ENERGY FROM THIS WAVE IS EXPECTED
TO STAY ACROSS NORTH GA BUT BOTH OUR LOCAL WRF AND THE HRRR SHOW A
BIT MORE DIURNALLY DRIVEN POP UP SHRA/TSRA ACROSS THE STATE THROUGH
02-04Z TONIGHT. THE SURFACE TO UPPER LEVEL RIDGE KEEPS OUR AREA IN
MOIST EASTERLY FLOW THROUGH THE SHORT TERM. THE MODELS ARE SHOWING
ANOTHER WEAKER WAVE MOVING ACROSS THE AREA THU IN THIS EASTERLY
FLOW. WITH THIS IN MIND SHOULD SEE ANOTHER DIURNALLY DRIVEN
CONVECTIVE DAY THU. THERE IS VERY LITTLE SHEAR IN THIS ATMOSPHERE
BUT THE CAPES AND LIS BOTH PEAK BETWEEN 18Z AND 00Z THIS AFTERNOON
AND THURSDAY. TODAY SHOULD BE THE WARMEST DAY THIS WEEK WITH RISING
THICKNESSES TODAY HOWEVER PRECIP/CLOUDS MAY OFFSET THE WARMING A
LITTLE. H5 HEIGHTS WILL BE DROPPING THURSDAY YIELDING A SLIGHTLY
COOLER TEMPS. STAYING CLOSE TO CURRENT FORECAST TEMPS AS THEY STILL
LOOKS GOOD.
01
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
NO SIG CHANGES TO THE EXTENDED. ONLY CHANGE WERE TO THE POPS ON
SUNDAY WHERE OUR NEIGHBORS AND GUIDANCE SUGGESTS A LIKELY CHANCE
OF POPS. DECIDED TO GO WITH THAT FOR SUNDAY AFTERNOON. OTHERWISE
UPDATED THE DEWPOINTS...WINDS AND TEMPERATURES WITH NEW GUIDANCE.
HAVE ATTACHED PREVIOUS DISCUSSION FOR BREVITY.
ARG
&&
.PREV DISCUSSION... /ISSUED 730 AM EDT WED JUL 17 2013/
LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
/ISSUED AT 355 AM EDT WED JUL 17 2013/
A TRANSITION TAKES PLACE THIS PERIOD FROM EAST FLOW ALOFT TO
WESTERLY FLOW WITH A UPPER TROUGH DEVELOPING OVER THE EASTERN
STATES. GFS AND EUROPEAN ARE SIMILAR WITH THIS CHANGE UNTIL THE
MONDAY TO WEDNESDAY TIME FRAME WHEN THE EUROPEAN MOVES THE TROUGH
TO THE WESTERN ATLANTIC AND THE GFS KEEPS THE UPPER TROUGH OVER THE
OH/TN VALLEYS AS A STRONGER UPPER SHORT WAVE MOVES OVER THE MID U.S.
PLENTY OF MOISTURE AND INSTABILITY THIS PERIOD FOR AT LEAST
SCATTERED SHOWERS AND THUNDERSTORMS FOR MOST AREAS...TENDING TO
MAXIMIZE IN THE AFTERNOON AND EVENING HOURS. DEEPER MOISTURE MOVES
ACROSS THE AREA WITH THE INITIAL ONSET OF THE UPPER TROUGH
SUNDAY/MONDAY AS A FRONT BECOMES STATIONARY JUST N OF GA AND A
SURFACE TROUGH SETS UP FROM THE CAROLINAS INTO GA. TEMPERATURES
GENERALLY CLOSE TO NORMAL EXCEPT HIGH TEMPERATURES WILL RUN
SLIGHTLY BELOW NORMAL FROM SATURDAY ON.
BDL
AVIATION...
00Z UPDATE...
TSTMS CONTINUE TO PUSH TO THE WEST...BUT SHOWING SIGNS OF
WEAKENING...AND PLENTY OF RAINFALL OVER MUCH OF AREA. CIGS MAINLY
VFR...BUT SOME MVFR CIGS IN TSRA/RA UNTIL 02Z. EXPECTING CIGS
TO REMAIN VFR THROUGHOUT PERIOD. VSBYS MAINLY VFR...BUT AGAIN SOME
MVFR VSBYS IN TSRA/RA...AND WEAKENING TSTMS UNTIL 02Z. WITH
WIDESPREAD RAINFALL...UNCERTAIN AS TO WHETHER MVFR CONDS WILL
DEVELOP FROM SUCH A MOIST AIRMASS. MODELS NOT SHOWING ANY CHANGE IN
PATTERN...HENCE WOULD EXPECT SIMILAR OCCURRENCES TOMORROW FOR MORE
SCATTERED AFTERNOON STORM DEVELOPMENT ACROSS AREA.
//ATL CONFIDENCE...00Z UPDATE...
MODERATE TO LOW CONFIDENCE ON CIG AND VSBY. MODERATE ON WINDS.
37
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 71 92 71 90 / 40 30 30 40
ATLANTA 74 91 73 88 / 40 30 30 50
BLAIRSVILLE 69 88 68 84 / 40 50 30 50
CARTERSVILLE 70 91 71 89 / 40 40 30 50
COLUMBUS 73 94 73 90 / 20 30 30 50
GAINESVILLE 73 90 73 88 / 40 40 30 50
MACON 71 92 71 90 / 30 30 20 40
ROME 71 92 71 90 / 40 40 30 50
PEACHTREE CITY 71 91 70 89 / 40 30 30 50
VIDALIA 72 93 72 89 / 20 30 20 40
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...01
LONG TERM....ARG
AVIATION...01
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
130 PM EDT TUE JUL 16 2013
.PREV DISCUSSION...
UPDATE...
/ISSUED 1137 AM EDT TUE JUL 16 2013/
MAIN CHANGE FOR THE UPDATE WAS TO REDUCE POPS INITIALLY. HRRR IS
SUGGESTING EXTENSIVE DEVELOPMENT ACROSS THE MOUNTAINS THIS
AFTERNOON. NAM/SREF/GFS ARE PICKING UP ON SOME ACTIVITY UP THERE
AFTER 18Z. WILL BE WATCHING THIS AREA FOR THE POTENTIAL NEED TO
INCREASE POPS ACROSS THE MOUNTAINS INTO THE AFTERNOON. HAVE CHANCE
POPS ACROSS THE SOUTHERN THIRD OF THE CWA...BUT SHOULD SEE BETTER
COVERAGE REMAIN SOUTH AND EAST OF THE AREA.
11
SHORT TERM /TODAY THROUGH WEDNESDAY/...
UPPER RIDGE REMAINS ANCHORED OVER THE OHIO VALLEY/GREAT LAKES AREA
TODAY INTO WEDNESDAY. EASTERLY FLOW WILL DOMINATE THROUGH MOST
LEVELS OF THE ATMOSPHERE THROUGH THE SHORT TERM. FORECAST SOUNDINGS
SHOWING PRECIPITABLE WATER DECREASING SOME TODAY. POPS IN THE 20 TO
30 PERCENT RANGE LOOK REASONABLE ACROSS THE CWA...FAVORING THE
AFTERNOON AND DIMINISHING AROUND 04Z. FOR WEDNESDAY...BOTH GFS AND
NAM INDICATE A WEAK SHORT WAVE MOVING WESTERLY AROUND THE EDGE OF
THE RIDGE FROM THE CAROLINAS INTO GA. ALSO...PW VALUES ARE ON THE
INCREASE BY THEN. BASED ON THIS HAVE PUSHED POPS UP A BIT ON
WEDNESDAY...STILL MOSTLY DIURNAL. MAX TEMPERATURES SHOULD RANGE IN
THE MID 80S TO LOW 90S NEXT COUPLE OF DAYS.
41
LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
HIGH PRESSURE ALOFT WILL BE OVER THE OH-MID MS VALLEYS TO START THE
LONG TERM AND IS FORECAST TO WEAKEN THURSDAY. A MOIST AIRMASS WILL
STILL BE IN PLACE AND WITH ANY INSTABILITY WILL LEAD TO ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS. MODELS HINTING THAT AN UPPER
LEVEL DISTURBANCE COULD AFFECT THE AREA THURSDAY AND THIS IS MAKING
TIMING OF ANY CONVECTION DIFFICULT AS CONVECTION COULD OCCUR EARLIER
ON THURSDAY THAN THE MORE NORMAL DIURNAL TENDENCY.
UPPER HIGH CONTINUES TO WEAKEN ON FRIDAY WITH PLENTY OF MOISTURE AND
AFTERNOON/EVENING INSTABILITY IN PLACE. A TRANSITION TO WESTERLY FLOW
OCCURS STARTING SATURDAY AND THIS EVENTUALLY DEVELOPS INTO A TROUGH
ALOFT INTO TUESDAY WITH POTENTIAL FOR SHORT WAVE ENHANCEMENT OF ANY
CONVECTION. PLENTY OF MOISTURE WILL CONTINUE TO BE AVAILABLE ALONG
WITH MAINLY DIURNAL INSTABILITY. THIS WILL LEAD TO AT LEAST
SCATTERED SHOWERS AND THUNDERSTORMS THROUGH THE PERIOD INTO TUESDAY.
TEMPERATURES SHOULD GENERALLY BE CLOSE TO NORMAL WITH THE HIGHS
SLIGHTLY BELOW NORMAL FROM ABOUT SATURDAY ON.
BDL
&&
.AVIATION...
18Z UPDATE...
BEST CHANCES FOR CONVECTION THIS AFTERNOON SHOULD BE ACROSS THE
NORTH GEORGIA MOUNTAINS AND ACROSS THE SOUTHERN PORTIONS OF
CENTRAL GEORGIA...THUS NORTH AND SOUTH OF THE TAF SITES. MCN HAS
THE BEST CHANCE OF SEEING A TSRA...BUT CHANCE IS SO LOW AT ALL THE
SITES THAT IT ISNT MENTIONED IN THE TAFS FOR THIS AFTERNOON.
SHOULD SEE SCT-BKN CLOUDS CONTINUE THROUGH THE AFTERNOON...BUT
CLOUD HEIGHTS SHOULD CONTINUE TO INCREASE.
//ATL CONFIDENCE...18Z UPDATE...
HIGH CONFIDENCE ON WIND..EXCEPT LOW CONFIDENCE ON TIMING OF WIND
SHIFT TOMORROW. HIGH CONFIDENCE ON CIGS AND VSBYS.
11
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 91 71 91 71 / 20 20 40 40
ATLANTA 87 73 91 72 / 20 20 40 40
BLAIRSVILLE 89 67 87 67 / 20 20 40 40
CARTERSVILLE 90 70 91 68 / 20 20 40 40
COLUMBUS 91 73 92 73 / 20 20 20 20
GAINESVILLE 89 72 91 72 / 20 20 40 40
MACON 91 70 92 70 / 20 20 30 30
ROME 91 70 92 69 / 20 20 40 40
PEACHTREE CITY 89 70 91 69 / 20 20 40 40
VIDALIA 91 73 91 72 / 30 30 20 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...11
LONG TERM....01
AVIATION...11
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
1137 AM EDT TUE JUL 16 2013
.UPDATE...
MAIN CHANGE FOR THE UPDATE WAS TO REDUCE POPS INITIALLY. HRRR IS
SUGGESTING EXTENSIVE DEVELOPMENT ACROSS THE MOUNTAINS THIS
AFTERNOON. NAM/SREF/GFS ARE PICKING UP ON SOME ACTIVITY UP THERE
AFTER 18Z. WILL BE WATCHING THIS AREA FOR THE POTENTIAL NEED TO
INCREASE POPS ACROSS THE MOUNTAINS INTO THE AFTERNOON. HAVE CHANCE
POPS ACROSS THE SOUTHERN THIRD OF THE CWA...BUT SHOULD SEE BETTER
COVERAGE REMAIN SOUTH AND EAST OF THE AREA.
11
&&
.PREV DISCUSSION...
SHORT TERM /TODAY THROUGH WEDNESDAY/...
UPPER RIDGE REMAINS ANCHORED OVER THE OHIO VALLEY/GREAT LAKES AREA
TODAY INTO WEDNESDAY. EASTERLY FLOW WILL DOMINATE THROUGH MOST
LEVELS OF THE ATMOSPHERE THROUGH THE SHORT TERM. FORECAST SOUNDINGS
SHOWING PRECIPITABLE WATER DECREASING SOME TODAY. POPS IN THE 20 TO
30 PERCENT RANGE LOOK REASONABLE ACROSS THE CWA...FAVORING THE
AFTERNOON AND DIMINISHING AROUND 04Z. FOR WEDNESDAY...BOTH GFS AND
NAM INDICATE A WEAK SHORT WAVE MOVING WESTERLY AROUND THE EDGE OF
THE RIDGE FROM THE CAROLINAS INTO GA. ALSO...PW VALUES ARE ON THE
INCREASE BY THEN. BASED ON THIS HAVE PUSHED POPS UP A BIT ON
WEDNESDAY...STILL MOSTLY DIURNAL. MAX TEMPERATURES SHOULD RANGE IN
THE MID 80S TO LOW 90S NEXT COUPLE OF DAYS.
41
LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
HIGH PRESSURE ALOFT WILL BE OVER THE OH-MID MS VALLEYS TO START THE
LONG TERM AND IS FORECAST TO WEAKEN THURSDAY. A MOIST AIRMASS WILL
STILL BE IN PLACE AND WITH ANY INSTABILITY WILL LEAD TO ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS. MODELS HINTING THAT AN UPPER
LEVEL DISTURBANCE COULD AFFECT THE AREA THURSDAY AND THIS IS MAKING
TIMING OF ANY CONVECTION DIFFICULT AS CONVECTION COULD OCCUR EARLIER
ON THURSDAY THAN THE MORE NORMAL DIURNAL TENDENCY.
UPPER HIGH CONTINUES TO WEAKEN ON FRIDAY WITH PLENTY OF MOISTURE AND
AFTERNOON/EVENING INSTABILITY IN PLACE. A TRANSITION TO WESTERLY FLOW
OCCURS STARTING SATURDAY AND THIS EVENTUALLY DEVELOPS INTO A TROUGH
ALOFT INTO TUESDAY WITH POTENTIAL FOR SHORT WAVE ENHANCEMENT OF ANY
CONVECTION. PLENTY OF MOISTURE WILL CONTINUE TO BE AVAILABLE ALONG
WITH MAINLY DIURNAL INSTABILITY. THIS WILL LEAD TO AT LEAST
SCATTERED SHOWERS AND THUNDERSTORMS THROUGH THE PERIOD INTO TUESDAY.
TEMPERATURES SHOULD GENERALLY BE CLOSE TO NORMAL WITH THE HIGHS
SLIGHTLY BELOW NORMAL FROM ABOUT SATURDAY ON.
BDL
AVIATION...
12Z UPDATE...
/ISSUED 742 AM EDT TUE JUL 16 2013/
EASTERLY WINDS SUPPORTING LIFR/IFR STRATUS AND FOG THIS MORNING OVER
MOST TAF SITES. IMPROVING TO MVFR AROUND 15Z THEN TO VFR BY 17Z.
WIDELY SCATTERED CONVECTION POSSIBLE MAINLY AFTERNOON INTO THE
EVENING BUT HAVE LEFT THUNDER OUT OF TAFS FOR NOW SINCE POPS ARE
ONLY 20 TO 30 PERCENT. EASTERLY WINDS PREVAILING TODAY AT 8 TO 10KT
OCCASIONALLY 15KT AT ATLANTA.
//ATL CONFIDENCE...12Z UPDATE...
MEDIUM CONFIDENCE FOR IMPROVEMENT OF CEILINGS. HIGH CONFIDENCE
REMAINING ELEMENTS.
41
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 91 71 91 71 / 20 20 40 30
ATLANTA 87 73 91 72 / 20 20 40 20
BLAIRSVILLE 89 67 87 67 / 20 20 40 30
CARTERSVILLE 90 70 91 68 / 20 20 40 20
COLUMBUS 91 73 92 73 / 30 20 30 20
GAINESVILLE 89 72 91 72 / 20 20 40 30
MACON 91 70 92 70 / 30 20 30 20
ROME 91 70 92 69 / 20 20 40 20
PEACHTREE CITY 89 70 91 69 / 20 20 40 20
VIDALIA 91 73 91 72 / 30 30 20 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...11
LONG TERM....01
AVIATION...11
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
140 AM EDT TUE JUL 16 2013
.UPDATE...
22Z SURFACE ANALYSIS SHOWS HIGH PRESSURE BUILDING IN FROM THE NE
ACROSS THE CWFA. OVER THE LAST FEW HOURS...MOST OF THE STRONGER
AFTERNOON CONVECTION HAS MOVED OFF TO THE WEST. ADDITIONAL SHOWERS
IN THE EAST ARE MOVING INTO AREAS THAT HAVE BEEN SLIGHTLY
STABILIZED WITH EARLIER ACTIVITY. THE LATEST RUNS OF THE HRRR SHOW
A DIMINISHING TREND IN CONVECTION AFTER 02Z. THIS SEEMS REASONABLE
AND HAVE FOLLOWED CLOSELY. HAVE ALSO REMOVED ALL MENTION OF
ISOLATED POPS AFTER 02AM. HIGH RESOLUTION MODELS ALSO SUPPORT
THIS.
&&
.PREV DISCUSSION... /ISSUED 346 PM EDT MON JUL 15 2013/
SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
A SLUG OF ATLANTIC MOISTURE WILL CONTINUE TO ADVECT WESTWARD ACROSS
THE CWA THIS AFTERNOON INTO EVENING ALONG THE SOUTHERN EXTEND OF AN
UPPER HIGH CENTERED OVER THE OHIO VALLEY. WHILE MLCAPE VALUES ARE
HIGHER TODAY THAN YESTERDAY AT NEAR 2000 J/KG...PWATS ARE NEAR 2.0
INCHES AGAIN AND DEVELOPMENT IS LARGELY TROPICAL IN NATURE. THERE
COULD BE SOME ISOLATED STRONG STORMS BUT NOT EXPECTED ANYTHING
SEVERE.
WHILE THE UPPER RIDGE SLOWLY DAMPENS AND RETROGRADES WEST THROUGH
TUESDAY...CANNOT RULE OUT A CHANCE OF SHOWERS AND THUNDERSTORMS
MAINLY IN THE AFTERNOON WITH CONTINUED EASTERLY FETCH AND DECENT
CAPE. HAVE GONE WITH CHANCE POPS SOUTH AND SLIGHT ELSEWHERE. ANOTHER
LOBE OF ENHANCED DEEPER MOISTURE APPROACHES THE NORTHEAST PART OF
THE AREA TUESDAY NIGHT SO HAVE INCREASED CLOUD COVERAGE...WHILE POPS
SHOULD BE ON THE RISE INTO WEDNESDAY.
FOR TEMPS...USED BLEND OF GUIDANCE AS THIS HAS VERIFIED WELL
RECENTLY. MAX VALUES SHOULD REBOUND TO BACK NEAR NORMAL TUESDAY IN
THE UPPER 80S TO LOW 90S.
BAKER
LONG TERM /WEDNESDAY THROUGH MONDAY/...
NO MAJOR CHANGES IN THE CURRENT EXTENDED FORECAST. HIGH PRESSURE
ALOFT WILL BE OVER THE OH- MID MS VALLEYS TO START THE LONG TERM.
A MOIST AIRMASS WILL STILL BE IN PLACE AS A DEEP EASTERLY FLOW
PATTERN PERSISTS. THIS SHOULD ALLOW A MORE DIURNAL TENDENCY TO ANY
CONVECTION TUESDAY NIGHT AND WEDNESDAY.
THIS PATTERN LOOKS TO CONTINUE ON THURSDAY AND FRIDAY BUT WITH THE
UPPER RIDGE WEAKENING AND THE UPPER FLOW BECOMING MORE WESTERLY FOR
SATURDAY INTO MONDAY. SCATTERED SHOWERS AND THUNDERSTORMS CAN BE
EXPECTED FOR MOST AREAS THROUGH MONDAY WITH THE GREATEST COVERAGE
IN THE AFTERNOON AND EVENING HOURS. THE POTENTIAL FOR SOME
ENHANCEMENT FROM SHORT WAVE ENERGY WILL INCREASE FROM SATURDAY ON
ALONG WITH DEEPER MOISTURE AVAILABLE. ALL IN ALL TEMPERATURES
SHOULD GENERALLY BE CLOSE TO NORMAL WITH THE HIGHS SLIGHTLY BELOW
NORMAL LATER IN THE PERIOD.
BDL/01
&&
.AVIATION...
06Z UPDATE...
SOME MVFR CLOUDS POSSIBLE TOWARD 09Z...AND MAY BE SOME IFR FORMING
ALSO BUT DO NOT EXPECT IT TO BE WIDESPREAD. STRATUS IMPROVING TO VFR
BY 15Z. LIGHT EAST WINDS UNTIL 14Z THEN INCREASING TO 10 TO 15KT.
WIDELY SCATTERED SHOWERS AND THUNDERSTORMS MAINLY THIS AFTERNOON.
WILL LEAVE OUT OF TAFS FOR NOW SINCE POPS ONLY 20 TO 30 PERCENT.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM CONFIDENCE FOR CIGS. HIGH CONFIDENCE REMAINING ELEMENTS.
&&
41
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 70 89 70 91 / 20 20 20 50
ATLANTA 70 88 73 89 / 30 20 20 50
BLAIRSVILLE 65 87 67 86 / 20 20 20 50
CARTERSVILLE 70 90 69 90 / 30 20 20 50
COLUMBUS 72 90 73 91 / 30 30 20 30
GAINESVILLE 70 88 72 88 / 20 20 20 50
MACON 70 89 70 91 / 30 30 20 30
ROME 70 91 69 91 / 30 20 20 50
PEACHTREE CITY 69 87 68 89 / 30 20 20 50
VIDALIA 72 90 72 93 / 30 30 30 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
509 PM CDT TUE JUL 16 2013
.DISCUSSION...
248 PM CDT
PRIMARY FORECAST CHALLENGE REMAINS THE HEAT AND HUMIDITY AND THE
POTENTIAL FOR HEAT HEADLINES LATER THIS WEEK.
STRONG UPPER RIDGE REMAINS SITUATED OVER THE REGION AND DESPITE
CONCERNS EARLIER THIS MORNING TO THE CONTRARY...HAS GENERALLY KEPT A
CHECK ON ISOLATED AFTERNOON THUNDERSTORM DEVELOPMENT. IT REMAINS
UNSTABLE AND LARGELY UNCAPPED...SO CAN`T RULE OUT SOME RENEGADE
STORMS POPPING BUT THINKING COVERAGE WILL BE LESS THAN EARLIER
FEARED THIS AFTERNOON. REALLY LOOKS LIKE THE SAME STORY WEDNESDAY
AND THURSDAY AS WELL WITH STRONG UPPER RIDGE OVERHEAD AND NO SUPPORT
ALOFT DESPITE STRONG INSTABILITY AND MINIMAL CAPPING...SO PLAN TO
KEEP POPS IN THE 10-15% RANGE IN THE GRIDS AND THE MENTION OF
THUNDERSTORMS OUT OF THE TEXT PRODUCTS FOR NOW WITH THE EXPECTATION
OF ANYTHING THAT DOES MANAGE TO DEVELOP REMAINING HIGHLY ISOLATED.
REGARDING TEMPS AND HEAT INDICES...EXPECT TOMORROW TO BE LARGELY A
REPEAT OF TODAY OR MAYBE A SMIDGE HOTTER WITH THURSDAY THE SAME
STORY. HEAT INDICES THIS AFTERNOON HAVE GENERALLY CLIMBED INTO THE
95-100 RANGE EXCEPT AT A COUPLE OF AWOS SITES THAT HAVE THE MOST
PROFUSELY SWEATING CORN AROUND IT (IE. DKB/SQI). ASSUMING DEWPOINTS
HOLD IN THE LOW 70S THE NEXT COUPLE DAYS (WHICH SEEMS
REASONABLE)...THEN HEAT INDICES WOULD LIKELY TOP OUT AROUND 100
WEDNESDAY AND A BIT ABOVE 100 THURSDAY AND FRIDAY. LOW TEMPS IN THE
OUTLYING AREAS LAST NIGHT WERE MOSTLY IN THE LOW 70S...SO UNLESS LOW
TEMPS START HOLDING IN THE MID TO UPPER 70S IN OUTLYING AREAS THE
NEXT COUPLE NIGHTS WE WILL PROBABLY BE ABLE TO HOLD OFF ON THE 4
DAY OF 100F+ HEAT INDEX CRITERIA FOR AN ADVISORY. COOK COUNTY AND
THE CITY OF CHICAGO IS A DIFFERENT STORY ONLY REQUIRING 3 DAYS OF
100-105 HEAT INDICES WITH EITHER 85% SUNSHINE 2 OF THE DAYS OR
NIGHT TIME HEAT INDICES ABOVE 80 FOR AN EXCESSIVE HEAT WARNING AND
WE WILL BE VERY CLOSE TO THIS CRITERIA WED-FRI. WE ARE FLIRTING
WITH 100F HEAT INDICES THIS AFTERNOON...THOUGH LAKE BREEZE HAS
RESULTING IN COOLING CLOSE TO THE LAKE. WEDNESDAY COULD SEE SOME
LAKE COOLING AGAIN BUT THURSDAY AND ESPECIALLY FRIDAY SHOULD BE
VOID OF ANY LAKE BREEZES. PONDERED AN EXCESSIVE HEAT WATCH FOR
COOK COUNTY BUT STILL NOT TERRIBLY CONFIDENT IN SOLIDLY REACHING
100F H.I. CRITERIA TOMORROW WITH LAKE BREEZE POTENTIAL...SO HAVE
OPTED TO HOLD OFF ON ANY HEADLINES FOR NOW.
FAIRLY HEALTHY COLD FRONT STILL SLATED TO MOVE THROUGH FRIDAY NIGHT
POTENTIALLY BRINGING A ROUND OF SHOWERS AND THUNDERSTORMS TO THE
AREA LATE FRIDAY AND ESPECIALLY FRIDAY NIGHT. COOLER AND MUCH LESS
HUMID AIR MASS WILL FILTER INTO THE REGION THIS WEEKEND LIKELY
LEADING TO A PRECIPITATION FREE WEEKEND.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* LAKE BREEZE TO STAY EAST OF AIRPORTS
* VERY SMALL CHANCE OF A THUNDERSTORM NEXT 2-3 HOURS
* SOME HAZE/LIGHT FOG AROUND SUNRISE
ALLSOPP
//DISCUSSION...UPDATED 22Z...
LAKE BREEZE NOT MAKING ANY PROGRESS INLAND. HIGH RES HRRR MODEL
STILL SUGGESTING LAKE BREEZE WILL MAKE IT OUT TO ORD AND MDW BUT
NOT TIL AFTER 00Z...BUT OTHER SHORT RANGE HIGH RES GUIDANCE KEEPS
IT ALONG THE SHORE. BASED ON CURRENT TRENDS HAVE DECIDED TO BACK
OFF AND LEAVE WINDS SOUTHWEST THROUGH EARLY EVENING. ALSO THERE
HAS BEEN NO CONVECTION ALONG THE LAKE BREEZE THIS FAR AND VISIBLE
SATELLITE ACTUALLY SHOWING DECREASING TREND IN CUMULUS FIELD LAST
COUPLE HOURS. STILL CANT COMPLETELY RULE OUT AN ISOLATED SHOWER OR
THUNDERSTORMS POPPING ALONG THE LAKE BREEZE BUT FEEL THE CHANCE
OF IT OCCURRING WITHIN 5 MILES OF EITHER AIRPORT IS 10 PERCENT OR
LESS. THEREFORE HAVE DROPPED THE VCTS FROM TAFS.
ALLSOPP
PREVIOUS DISCUSSION 18Z...
CONCERNS FOR A LAKE BREEZE THIS AFTERNOON AND A WIND SHIFT DUE TO A
LAKE BREEZE CONTINUE THIS AFTERNOON. THE AREA REMAINS UNDER A VERY
UNSTABLE AND WEAKLY CAPPED AIRMASS. WEAK MID LEVEL LAPSE RATES AND
LACK OF ANY UPPER LEVEL SUPPORT HAVE INHIBITED DEEP CONVECTION THUS
FAR...BUT MODIFIED NAM/AMDAR SHOW THAT WITH ONLY A LITTLE MORE
SURFACE HEATING...DEEP CONVECTION/THUNDERSTORM DEVELOPMENT REMAINS A
DISTINCT POSSIBILITY. LACK OF ANY SYNOPTIC FORCING MAY KEEP COVERAGE
ON THE LOW END...BUT THE LAKE BREEZE STILL APPEARS TO BE THE BEST
FOCUS...AND ANY THUNDERSTORMS THAT DO DEVELOP WILL LIKELY BE SLOW
MOVING AND PULSY.
THE LAKE BREEZE HAS BEEN SLOW TO DEVELOP WITH MODEST SOUTHWEST FLOW
IN PLACE...BUT SENSORS IN DOWNTOWN CHICAGO AND AT THE CHICAGO CRIB A
FEW MILES OFF SHORE HAVE SHOWN HINTS OF IT TRYING TO BECOME BETTER
ORGANIZED...INCLUDING THE NORTHERLY ISLAND SENSOR RECENTLY TURNING
E. PUSHED BACK THE TIMING WHICH IS IN LINE WITH LATEST RAP/HRRR RUNS
THOUGH CONFIDENCE ON REACHING THE TERMINALS IS LESS THAN BEFORE.
OVERNIGHT...LIGHT SOUTHWESTERLY WINDS WILL TAKE OVER AGAIN. MUGGY
AIRMASS REMAINS IN PLACE AND COOLING WILL LEAD TO MODEST REDUCTIONS
IN VSBY DUE TO MIST/HAZE.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* LOW CONFIDENCE IN LAKE BREEZE MAKING TO ORD OR MDW.
* LOW CONFIDENCE IN THUNDERSTORM OCCURRING WITHIN 5 MILES OF ORD/MDW.
* MEDIUM CONFIDENCE IN HAZE OR LIGHT FOG AROUND SUNRISE.
ALLSOPP
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...MVFR VISIBILITY OVERNIGHT DUE TO BR HZ.
OTHERWISE...VFR...NO SIG WX.
THURSDAY...POSSIBLE MVFR VISIBILITY EARLY MORNING AND LATE
OVERNIGHT DUE TO BR HZ. OTHERWISE...VFR...NO SIG WX.
FRIDAY...INCREASING CHANCES OF TS AS DAY PROGRESSES...FROM SLIGHT
CHANCE IN THE MORNING TO CHANCE IN AFTERNOON AND LIKELY FRIDAY
NIGHT. ANY TSRA WOULD PRODUCE OF MVFR AND POSSIBLY BRIEF IFR
CONDITIONS.
SATURDAY...SLIGHT CHANCE OF TS. OTHERWISE VFR.
SUNDAY...VFR...NO SIG WX.
MONDAY...CHANCE OF TSRA...OTHERWISE VFR.
&&
.MARINE...
303 PM CDT
LIGHT SOUTH/SOUTHWEST FLOW WILL CONTINUE OVER THE OPEN WATERS
THROUGH THURSDAY. A COLD FRONT WILL LIKELY STALL JUST NORTH OF THE
NORTH TIP OF THE LAKE BY EARLY THURSDAY BEFORE WASHING OUT. THEN
A STRONGER COLD FRONT WILL PUSH DOWN THE LAKE ON FRIDAY...WITH A
TIGHTER PRESSURE GRADIENT AHEAD OF IT RESULTING IN STRONGER
SOUTHWEST WINDS. STABLE CONDITIONS WILL KEEP GUSTINESS DOWN EXCEPT
FOR THE NEAR SHORE WATERS WHERE GUSTS NEAR AROUND 25 KT ARE
POSSIBLE FRIDAY AFTERNOON. BEHIND THE FRONT...MODEST COLD
ADVECTION WILL BRING A PERIOD OF GUSTY NORTHERLY WINDS
SATURDAY...FOLLOWED BY HIGH PRESSURE QUICKLY BUILDING IN AND
LIGHTER WINDS FOR SUNDAY.
THE NEAR SHORE WATERS WILL SEE DIURNAL LAKE BREEZE INFLUENCE SIMILAR
TO TODAY ON WEDNESDAY BUT THEN ON THURSDAY...STRONGER WINDS ABOVE
THE SURFACE SHOULD LARGELY PREVENT THE DEVELOPMENT OF A LAKE BREEZE.
RC
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
132 PM CDT TUE JUL 16 2013
.DISCUSSION...
939 AM CDT
GOING FORECAST LOOKS TO BE IN GOOD SHAPE WITH NO BIG CHANGES
PLANNED AT THIS TIME...JUST A SLIGHT UPWARD ADJUSTMENT TO POPS.
MORNING SOUNDINGS AGAIN TODAY WERE VERY MOIST IN THE LOW LEVELS
THOUGH SLIGHTLY DRIER ABOVE 700MB AS COMPARED WITH YESTERDAY. PWATS
ARE DOWN ABOUT A QUARTER TO A HALF INCH OR FROM YESTERDAY`S LEVELS
BUT REMAIN 150% OR MORE OF AVERAGE. STRONG UPPER RIDGE HAS SHIFTED
WEST A BIT FROM YESTERDAYS POSITION WITH 500MB HEIGHTS 20-30 METERS
HIGHER THAN YESTERDAY. MID LEVEL TEMPS REMAIN VERY WARM WITH WEAK
MID LEVEL LAPSE RATES...HOWEVER ILX/DVN MORNING RAOBS AND ACARS OUT
OF MDW THIS MORNING SHOW NO INVERSION OR POTENTIAL CAPPING LAYER. SO
WHILE WE DONT HAVE ANY SHORTWAVE ALOFT TO PROVIDE FORCING LIKE
YESTERDAY AND WHILE PWATS ARE DOWN A BIT...STILL THINK ISOLATED
CONVECTION IS A DECENT BET TODAY. BOTH THE RUC FORECAST SOUNDINGS
AND MODIFIED OBSERVED SOUNDINGS SUGGEST MLCAPE VALUES REACHING
3000-3500 J/KG WITH LITTLE/NO INHIBITION.
AS MENTIONED THERE IS NO FORCING ALOFT TODAY AS WE SIT PARKED ALMOST
DIRECTLY UNDER THE UPPER RIDGE...HOWEVER VWP SHOWS SOUTHWEST WINDS
OFF THE DECK DIMINISHING FROM THE NOCTURNAL MAXIMA AND THINK WE
SHOULD ONCE AGAIN SEE A LAKE BREEZE FORM THIS AFTERNOON. GIVEN THE
LOW LFC`S THE SHALLOW FORCING ALONG THE LAKE BREEZE WITH NO CAP
SHOULD ONCE AGAIN BE ENOUGH TO KICK OFF ISOLATED TO WIDELY SCATTERED
AFTERNOON THUNDERSTORMS. ALREADY SEEING VERY HEALTHY CUMULUS FIELD
BLOSSOMING NEAR THE CONVERGENCE ZONE DOWNTOWN...SO GIVEN THE SET UP
AM PLANNING TO BUMP UP POPS SOME TODAY OVER LAKE AND COOK COUNTIES
IN ILLINOIS LATE THIS MORNING INTO THE AFTERNOON. THE SLIGHTLY DRIER
AIR ALOFT TODAY ALONG WITH SLIGHTLY STRONGER INSTABILITY ACTUALLY
RAISES THE MICROBURST THREAT SOME OVER YESTERDAY AND THINK THE
THREAT OF A PULSE SEVERE THUNDERSTORM IS A BIT GREATER TODAY.
WILL GET SOME UPDATED GRIDS WITH SLIGHTLY HIGHER POPS OUT ALONG THE
LAKE BREEZE SHORTLY.
IZZI
//PREV DISCUSSION...
337 AM CDT
FORECAST FOCUS REMAINS ON HEAT/HUMIDITY OVER THE NEXT SEVERAL
DAYS...AND POTENTIAL FOR ISOLATED THUNDERSTORMS AGAIN THIS
AFTERNOON. HEAT HEADLINES MAY BE REQUIRED LATER IN THE WEEK FOR
CONSECUTIVE DAYS OF PEAK HEAT INDICES ABOVE 100.
00Z RAOB ANALYSIS DEPICTS 6000 METER 500MB HEIGHTS AT ILN...WITH
UPPER LEVEL RIDGE EXPECTED TO DRIFT ACROSS NORTHERN INDIANA LATER
TODAY AND ACROSS CENTRAL IL ON WEDNESDAY...BEFORE GRADUALLY
WEAKENING AND SHIFTING SOUTH ACROSS THE LOWER OHIO VALLEY LATE IN IN
THE WEEK. 850MB TEMPS OF +18/19C SAMPLED BENEATH THE RIDGE...WITH
MODEL FORECASTS INDICATING THESE SLOWLY WARMING AS THE RIDGE DRIFTS
WEST...REACHING +20/21C BY FRIDAY AS THE RIDGE DRIFTS SOUTH AND
WEST-SOUTHWEST LOW LEVEL FLOW ENHANCES WARM ADVECTION OFF THE
PLAINS. TEMPS MONDAY WERE GENERALLY 89-91 OUTSIDE OF THE LAKE BREEZE
AND THUNDERSTORM EFFECTS...AND DIAGNOSIS OF LOW LEVEL THERMAL FIELDS
FROM MODELS INDICATE WE SHOULD BE PERHAPS A DEGREE OR SO HIGHER
OVERALL TODAY...AND IN THE LOW-MID 90S WED-FRI. COMBINED WITH SFC
DEW POINT TEMPERATURES GENERALLY IN THE LOWER 70S...THE COMBINATION
OF HEAT/HUMIDITY SHOULD YIELD AFTERNOON PEAK HEAT INDEX VALUES
ROUGHLY 98-102 DEGREES FOR THE NEXT FOUR DAYS. MUGGY CONDITIONS WITH
NIGHTTIME TEMPS SLOWLY FALLING THROUGH THE MID/UPPER 70S WILL NOT
PROVIDE MUCH RELIEF AT NIGHT EITHER. THREE TO FOUR CONSECUTIVE DAYS
OF THESE CONDITIONS WOULD REQUIRE HEAT HEADLINES FOR THE CWA. THE
CAVEATS AT THIS TIME HOWEVER REMAINS THE POTENTIAL FOR ISOLATED
AFTERNOON THUNDERSTORMS AGAIN TODAY (AND WED/THU AS WELL) AND A
GREATER THREAT OF THUNDERSTORMS FRIDAY AFTERNOON WHICH COULD DISRUPT
TEMPS/HEAT INDEX VALUES DURING PEAK HEATING...AS WELL AS LOWERING
DEW POINT TEMPERATURES DURING AFTERNOON MIXING. WILL HOLD OFF ON
HOISTING ANY HEADLINES FOR NOW...AND MONITOR HOW THINGS PLAY OUT
THIS AFTERNOON.
SHIFTING TO THUNDERSTORM POTENTIAL...FORECAST SOUNDINGS CONTINUE TO
DEPICT UNSTABLE AND FAIRLY UNCAPPED THERMODYNAMIC PROFILES ACROSS
THE AREA AGAIN THIS AFTERNOON. WHILE NOT MUCH SUPPORT NOTED ON THE
LARGE SCALE...LACK OF SIGNIFICANT CAPPING DOES SUGGEST THE POTENTIAL
FOR AT LEAST A FEW ISOLATED THUNDERSTORMS THIS AFTERNOON
PARTICULARLY ACROSS NORTHERN PARTS OF THE IL CWA...WITH CONVERGENCE
ALONG WEAK LAKE BREEZE A POTENTIAL TRIGGER. CONVECTIVE OUTFLOW
BOUNDARIES FROM ANY ISOLATED STORMS THAT DO FORM WOULD ALSO PROVIDE
FOCUS FOR ADDITIONAL ISOLATED DEVELOPMENT...WHICH SHOULD WANE TOWARD
EVENING WITH LOSS OF DIURNAL COMPONENT OF INSTABILITY. THOUGH SPARSE
IN NUMBER AND COVERAGE...ANY STORMS THAT WOULD FORM WOULD LIKELY BE
SLOW-MOVING AND POTENTIALLY HEAVY RAIN PRODUCERS...WITH 2.03 INCH
PWAT NOTED IN DVN 00Z RAOB AND 1.90 INCHES AT ILX. WHILE AN ISOLATED
THUNDERSTORM MAY ALSO BE POSSIBLE WEDNESDAY AND THURSDAY
AFTERNOON...THE POTENTIAL SHOULD BE DECREASING AS THE RIDGE DRIFTS
CLOSER AND MID-LEVEL TEMPERATURES WARM. ALSO...IT APPEARS AS THOUGH
THERE WILL BE JUST ENOUGH WEST-SOUTHWEST FLOW IN LOW LEVELS AFTER
TODAY TO PREVENT THE LAKE BREEZE FROM MOVING INLAND...PROVIDING LESS
FOCUS FOR CONVECTIVE INITIATION.
AS INDICATED ABOVE...THE UPPER RIDGE IS ANTICIPATED TO WEAKEN AND
MOVE SOUTH THURSDAY AND FRIDAY...WITH MID/UPPER LEVEL WESTERLIES
SETTLING ACROSS THE UPPER MIDWEST. MODEL GUIDANCE REMAINS IN GOOD
AGREEMENT THAT AMPLIFICATION OF AN UPPER TROUGH WILL OCCUR ACROSS
CENTRAL CANADA AND THE UPPER MIDWEST BY FRIDAY NIGHT...WITH A COLD
FRONT SAGGING SOUTH INTO OUR AREA. THUNDERSTORM POTENTIAL LOOKS TO
INCREASE FRIDAY AFTERNOON AHEAD OF THE FRONT...AS LARGE SCALE ASCENT
DEVELOPS IN ADVANCE OF THE DEEPENING UPPER TROUGH AND LOW LEVEL
CONVERGENCE AND MOISTURE POOLING OCCUR ALONG AND SOUTH OF THE COLD
FRONTAL BOUNDARY. SOME LINGERING THREAT OF SHOWERS/THUNDERSTORMS MAY
LINGER INTO SATURDAY AS THE FRONT CONTINUES TO SAG SOUTHWARD...
THOUGH MAINLY ACROSS THE SOUTH/SOUTHEASTERN PARTS OF THE CWA. COOLER
AND LESS HUMID WEATHER CAN BE EXPECTED HOWEVER...AS HIGH PRESSURE
BUILDS SOUTHEAST ACROSS THE GREAT LAKES OVER THE WEEKEND AND SHIFTS
WINDS TO THE NORTH-NORTHEAST. A RETURN TO WARMER AND MORE HUMID
CONDITIONS LOOKS TO TAKE PLACE AGAIN EARLY NEXT WEEK HOWEVER...WITH
THE ECMWF QUICKER WITH THE RETURN MONDAY.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* LAKE BREEZE POTENTIAL AND TIMING MID TO LATE THIS AFTERNOON.
* WIDELY SCATTERED THUNDERSTORMS DEVELOPING EARLY TO MID THIS
AFTERNOON.
BMD
//DISCUSSION...UPDATED 18Z...
CONCERNS FOR A LAKE BREEZE THIS AFTERNOON AND A WIND SHIFT DUE TO A
LAKE BREEZE CONTINUE THIS AFTERNOON. THE AREA REMAINS UNDER A VERY
UNSTABLE AND WEAKLY CAPPED AIRMASS. WEAK MID LEVEL LAPSE RATES AND
LACK OF ANY UPPER LEVEL SUPPORT HAVE INHIBITED DEEP CONVECTION THUS
FAR...BUT MODIFIED NAM/AMDAR SHOW THAT WITH ONLY A LITTLE MORE
SURFACE HEATING...DEEP CONVECTION/THUNDERSTORM DEVELOPMENT REMAINS A
DISTINCT POSSIBILITY. LACK OF ANY SYNOPTIC FORCING MAY KEEP COVERAGE
ON THE LOW END...BUT THE LAKE BREEZE STILL APPEARS TO BE THE BEST
FOCUS...AND ANY THUNDERSTORMS THAT DO DEVELOP WILL LIKELY BE SLOW
MOVING AND PULSY.
THE LAKE BREEZE HAS BEEN SLOW TO DEVELOP WITH MODEST SOUTHWEST FLOW
IN PLACE...BUT SENSORS IN DOWNTOWN CHICAGO AND AT THE CHICAGO CRIB A
FEW MILES OFF SHORE HAVE SHOWN HINTS OF IT TRYING TO BECOME BETTER
ORGANIZED...INCLUDING THE NORTHERLY ISLAND SENSOR RECENTLY TURNING
E. PUSHED BACK THE TIMING WHICH IS IN LINE WITH LATEST RAP/HRRR RUNS
THOUGH CONFIDENCE ON REACHING THE TERMINALS IS LESS THAN BEFORE.
OVERNIGHT...LIGHT SOUTHWESTERLY WINDS WILL TAKE OVER AGAIN. MUGGY
AIRMASS REMAINS IN PLACE AND COOLING WILL LEAD TO MODEST REDUCTIONS
IN VSBY DUE TO MIST/HAZE.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* LOW TO MEDIUM CONFIDENCE IN LAKE BREEZE TIMING/REACHING TERMINALS.
* MEDIUM CONFIDENCE IN THUNDERSTORMS...COVERAGE SHOULD REMAIN
RELATIVELY LOW SO CONFIDENCE IN THUNDERSTORMS HITTING TERMINALS
IS LOW.
BMD
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...MVFR VISIBILITY OVERNIGHT DUE TO BR HZ.
OTHERWISE...VFR...NO SIG WX.
THURSDAY...POSSIBLE MVFR VISIBILITY EARLY MORNING AND LATE
OVERNIGHT DUE TO BR HZ. OTHERWISE...VFR...NO SIG WX.
FRIDAY...INCREASING CHANCES OF TS AS DAY PROGRESSES...FROM SLIGHT
CHANCE IN THE MORNING TO CHANCE IN AFTERNOON AND LIKELY FRIDAY
NIGHT. ANY TSRA WOULD PRODUCE OF MVFR AND POSSIBLY BRIEF IFR
CONDITIONS.
SATURDAY...SLIGHT CHANCE OF TS. OTHERWISE VFR.
SUNDAY...VFR...NO SIG WX.
MONDAY...CHANCE OF TSRA...OTHERWISE VFR.
&&
.MARINE...
339 AM CDT
A LARGE AREA OF HIGH PRESSURE CENTERED OVER THE OH VALLEY EARLY
THIS MORNING WILL CONTINUE TO SLOWLY SHIFT TO THE W AND WILL BE
CENTERED IN THE MID MS VALLEY BY WED NIGHT MAINTAINING LIGHT TO
GENTLE S TO SW BREEZES ON THE LAKE. DURING THU AND THU NIGHT SW
WINDS WILL GRADUALLY FRESHEN AS A COLD FRONT DROPS S ACROSS THE
N WOODS AND LAKE SUPERIOR WHERE IT WILL WEAKEN. A STRONGER COLD
FRONT WILL DROP S OVER NORTHERN LAKE MI DURING FRI AFTERNOON
WITH THE COLD FRONT CONTINUING S DOWN THE LAKE REACHING THE S
END BY DAWN SAT. HIGH PRESSURE BUILDING SE FROM CENTRAL CANADA
TO THE UPPER MIDWEST DURING FRI NIGHT AND SAT WILL MAINTAIN
GENTLE TO MODERATE N TO NE BREEZES THROUGH THAT PERIOD.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1106 AM CDT TUE JUL 16 2013
.DISCUSSION...
939 AM CDT
GOING FORECAST LOOKS TO BE IN GOOD SHAPE WITH NO BIG CHANGES
PLANNED AT THIS TIME...JUST A SLIGHT UPWARD ADJUSTMENT TO POPS.
MORNING SOUNDINGS AGAIN TODAY WERE VERY MOIST IN THE LOW LEVELS
THOUGH SLIGHTLY DRIER ABOVE 700MB AS COMPARED WITH YESTERDAY. PWATS
ARE DOWN ABOUT A QUARTER TO A HALF INCH OR FROM YESTERDAY`S LEVELS
BUT REMAIN 150% OR MORE OF AVERAGE. STRONG UPPER RIDGE HAS SHIFTED
WEST A BIT FROM YESTERDAYS POSITION WITH 500MB HEIGHTS 20-30 METERS
HIGHER THAN YESTERDAY. MID LEVEL TEMPS REMAIN VERY WARM WITH WEAK
MID LEVEL LAPSE RATES...HOWEVER ILX/DVN MORNING RAOBS AND ACARS OUT
OF MDW THIS MORNING SHOW NO INVERSION OR POTENTIAL CAPPING LAYER. SO
WHILE WE DONT HAVE ANY SHORTWAVE ALOFT TO PROVIDE FORCING LIKE
YESTERDAY AND WHILE PWATS ARE DOWN A BIT...STILL THINK ISOLATED
CONVECTION IS A DECENT BET TODAY. BOTH THE RUC FORECAST SOUNDINGS
AND MODIFIED OBSERVED SOUNDINGS SUGGEST MLCAPE VALUES REACHING
3000-3500 J/KG WITH LITTLE/NO INHIBITION.
AS MENTIONED THERE IS NO FORCING ALOFT TODAY AS WE SIT PARKED ALMOST
DIRECTLY UNDER THE UPPER RIDGE...HOWEVER VWP SHOWS SOUTHWEST WINDS
OFF THE DECK DIMINISHING FROM THE NOCTURNAL MAXIMA AND THINK WE
SHOULD ONCE AGAIN SEE A LAKE BREEZE FORM THIS AFTERNOON. GIVEN THE
LOW LFC`S THE SHALLOW FORCING ALONG THE LAKE BREEZE WITH NO CAP
SHOULD ONCE AGAIN BE ENOUGH TO KICK OFF ISOLATED TO WIDELY SCATTERED
AFTERNOON THUNDERSTORMS. ALREADY SEEING VERY HEALTHY CUMULUS FIELD
BLOSSOMING NEAR THE CONVERGENCE ZONE DOWNTOWN...SO GIVEN THE SET UP
AM PLANNING TO BUMP UP POPS SOME TODAY OVER LAKE AND COOK COUNTIES
IN ILLINOIS LATE THIS MORNING INTO THE AFTERNOON. THE SLIGHTLY DRIER
AIR ALOFT TODAY ALONG WITH SLIGHTLY STRONGER INSTABILITY ACTUALLY
RAISES THE MICROBURST THREAT SOME OVER YESTERDAY AND THINK THE
THREAT OF A PULSE SEVERE THUNDERSTORM IS A BIT GREATER TODAY.
WILL GET SOME UPDATED GRIDS WITH SLIGHTLY HIGHER POPS OUT ALONG THE
LAKE BREEZE SHORTLY.
IZZI
//PREV DISCUSSION...
337 AM CDT
FORECAST FOCUS REMAINS ON HEAT/HUMIDITY OVER THE NEXT SEVERAL
DAYS...AND POTENTIAL FOR ISOLATED THUNDERSTORMS AGAIN THIS
AFTERNOON. HEAT HEADLINES MAY BE REQUIRED LATER IN THE WEEK FOR
CONSECUTIVE DAYS OF PEAK HEAT INDICES ABOVE 100.
00Z RAOB ANALYSIS DEPICTS 6000 METER 500MB HEIGHTS AT ILN...WITH
UPPER LEVEL RIDGE EXPECTED TO DRIFT ACROSS NORTHERN INDIANA LATER
TODAY AND ACROSS CENTRAL IL ON WEDNESDAY...BEFORE GRADUALLY
WEAKENING AND SHIFTING SOUTH ACROSS THE LOWER OHIO VALLEY LATE IN IN
THE WEEK. 850MB TEMPS OF +18/19C SAMPLED BENEATH THE RIDGE...WITH
MODEL FORECASTS INDICATING THESE SLOWLY WARMING AS THE RIDGE DRIFTS
WEST...REACHING +20/21C BY FRIDAY AS THE RIDGE DRIFTS SOUTH AND
WEST-SOUTHWEST LOW LEVEL FLOW ENHANCES WARM ADVECTION OFF THE
PLAINS. TEMPS MONDAY WERE GENERALLY 89-91 OUTSIDE OF THE LAKE BREEZE
AND THUNDERSTORM EFFECTS...AND DIAGNOSIS OF LOW LEVEL THERMAL FIELDS
FROM MODELS INDICATE WE SHOULD BE PERHAPS A DEGREE OR SO HIGHER
OVERALL TODAY...AND IN THE LOW-MID 90S WED-FRI. COMBINED WITH SFC
DEW POINT TEMPERATURES GENERALLY IN THE LOWER 70S...THE COMBINATION
OF HEAT/HUMIDITY SHOULD YIELD AFTERNOON PEAK HEAT INDEX VALUES
ROUGHLY 98-102 DEGREES FOR THE NEXT FOUR DAYS. MUGGY CONDITIONS WITH
NIGHTTIME TEMPS SLOWLY FALLING THROUGH THE MID/UPPER 70S WILL NOT
PROVIDE MUCH RELIEF AT NIGHT EITHER. THREE TO FOUR CONSECUTIVE DAYS
OF THESE CONDITIONS WOULD REQUIRE HEAT HEADLINES FOR THE CWA. THE
CAVEATS AT THIS TIME HOWEVER REMAINS THE POTENTIAL FOR ISOLATED
AFTERNOON THUNDERSTORMS AGAIN TODAY (AND WED/THU AS WELL) AND A
GREATER THREAT OF THUNDERSTORMS FRIDAY AFTERNOON WHICH COULD DISRUPT
TEMPS/HEAT INDEX VALUES DURING PEAK HEATING...AS WELL AS LOWERING
DEW POINT TEMPERATURES DURING AFTERNOON MIXING. WILL HOLD OFF ON
HOISTING ANY HEADLINES FOR NOW...AND MONITOR HOW THINGS PLAY OUT
THIS AFTERNOON.
SHIFTING TO THUNDERSTORM POTENTIAL...FORECAST SOUNDINGS CONTINUE TO
DEPICT UNSTABLE AND FAIRLY UNCAPPED THERMODYNAMIC PROFILES ACROSS
THE AREA AGAIN THIS AFTERNOON. WHILE NOT MUCH SUPPORT NOTED ON THE
LARGE SCALE...LACK OF SIGNIFICANT CAPPING DOES SUGGEST THE POTENTIAL
FOR AT LEAST A FEW ISOLATED THUNDERSTORMS THIS AFTERNOON
PARTICULARLY ACROSS NORTHERN PARTS OF THE IL CWA...WITH CONVERGENCE
ALONG WEAK LAKE BREEZE A POTENTIAL TRIGGER. CONVECTIVE OUTFLOW
BOUNDARIES FROM ANY ISOLATED STORMS THAT DO FORM WOULD ALSO PROVIDE
FOCUS FOR ADDITIONAL ISOLATED DEVELOPMENT...WHICH SHOULD WANE TOWARD
EVENING WITH LOSS OF DIURNAL COMPONENT OF INSTABILITY. THOUGH SPARSE
IN NUMBER AND COVERAGE...ANY STORMS THAT WOULD FORM WOULD LIKELY BE
SLOW-MOVING AND POTENTIALLY HEAVY RAIN PRODUCERS...WITH 2.03 INCH
PWAT NOTED IN DVN 00Z RAOB AND 1.90 INCHES AT ILX. WHILE AN ISOLATED
THUNDERSTORM MAY ALSO BE POSSIBLE WEDNESDAY AND THURSDAY
AFTERNOON...THE POTENTIAL SHOULD BE DECREASING AS THE RIDGE DRIFTS
CLOSER AND MID-LEVEL TEMPERATURES WARM. ALSO...IT APPEARS AS THOUGH
THERE WILL BE JUST ENOUGH WEST-SOUTHWEST FLOW IN LOW LEVELS AFTER
TODAY TO PREVENT THE LAKE BREEZE FROM MOVING INLAND...PROVIDING LESS
FOCUS FOR CONVECTIVE INITIATION.
AS INDICATED ABOVE...THE UPPER RIDGE IS ANTICIPATED TO WEAKEN AND
MOVE SOUTH THURSDAY AND FRIDAY...WITH MID/UPPER LEVEL WESTERLIES
SETTLING ACROSS THE UPPER MIDWEST. MODEL GUIDANCE REMAINS IN GOOD
AGREEMENT THAT AMPLIFICATION OF AN UPPER TROUGH WILL OCCUR ACROSS
CENTRAL CANADA AND THE UPPER MIDWEST BY FRIDAY NIGHT...WITH A COLD
FRONT SAGGING SOUTH INTO OUR AREA. THUNDERSTORM POTENTIAL LOOKS TO
INCREASE FRIDAY AFTERNOON AHEAD OF THE FRONT...AS LARGE SCALE ASCENT
DEVELOPS IN ADVANCE OF THE DEEPENING UPPER TROUGH AND LOW LEVEL
CONVERGENCE AND MOISTURE POOLING OCCUR ALONG AND SOUTH OF THE COLD
FRONTAL BOUNDARY. SOME LINGERING THREAT OF SHOWERS/THUNDERSTORMS MAY
LINGER INTO SATURDAY AS THE FRONT CONTINUES TO SAG SOUTHWARD...
THOUGH MAINLY ACROSS THE SOUTH/SOUTHEASTERN PARTS OF THE CWA. COOLER
AND LESS HUMID WEATHER CAN BE EXPECTED HOWEVER...AS HIGH PRESSURE
BUILDS SOUTHEAST ACROSS THE GREAT LAKES OVER THE WEEKEND AND SHIFTS
WINDS TO THE NORTH-NORTHEAST. A RETURN TO WARMER AND MORE HUMID
CONDITIONS LOOKS TO TAKE PLACE AGAIN EARLY NEXT WEEK HOWEVER...WITH
THE ECMWF QUICKER WITH THE RETURN MONDAY.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* TIMING PASSAGE OF LAKE BREEZE AND WIND DIRECTION BEHIND BOUNDARY.
* POTENTIAL FOR SCATTERED TSRA...PARTICULARLY ALONG THE LAKE
BREEZE WHERE THE BEST CONVERGENCE WILL OCCUR...BUT ISOLATED
FARTHER INLAND.
* VSBY REDUCTION DUE TO BR/HZ EARLY WEDNESDAY MORNING.
BMD
//DISCUSSION...UPDATED 12Z...
VERY SLOW WESTWARD RETROGRESSION OF THE UPPER PATTERN ACROSS
THE EASTERN AND CENTRAL U.S WILL CONTINUE TODAY...THEN TO THE
WEST-SOUTHWEST TONIGHT. THE W TO E ELONGATED UPPER ANTICYCLONE
THAT CURRENTLY IS OVER FAR WESTERN LOWER MI IS TO RETREAT TO
AROUND THE CENTRAL PORTION OF THE IL-IN BOARDER BY LATE TONIGHT.
THE ASSOCIATED SURFACE HIGH CENTER IS ALSO DRIFTING WESTWARD
RESULTING IN THE LOW LEVEL FLOW OVER THE AREA BACKING FROM
SOUTHEASTERLY TO SOUTHWESTERLY OVERNIGHT PER WIND PROFILES FROM
WSR-88D NETWORK AS WELL AS TERMINAL DOPPLER INSTALLATIONS.
THIS SW FLOW WILL BE RATHER WEAK WITH PROGGED MIXED LAYER WINDS
OF ONLY UP TO AROUND 10 KT AT MOST DURING THE DAY. WHILE WEAK IT
IS EXPECTED TO LIMIT ANY LAKE BREEZE INLAND PENETRATION TO JUST
ALONG THE IMMEDIATE SHORELINES OF NW IN AND UP TO AROUND DOWNTOWN
CHICAGO...WITH DEEPER PENETRATION INLAND THE FURTHER ONES GOES
FROM THE LOOP N UP TO SE WI. EVEN MODELS THAT ARE MOST AGGRESSIVE
WITH THE LAKE BREEZE ONLY TAKE IT AS FAR W AS THE EASTERN BOARDER
OF THE ORD AIR FIELD SO THE TAFOR MAINTAINS SW SURFACE WINDS
THROUGH THE DAY.
WITH SOMEWHAT STAGNANT CONDITIONS UNDER THE ANTICYCLONE AN
INCREASE IN PARTICULATE MATTER AND COUPLED WITH DEW POINTS
REMAINING IN THE LOWER 70S IS EXPECTED TO RESULT IN VISIBILITY
BEING RESTRICTED BY SMOG FROM LATE OVERNIGHT TIL A COUPLE HOURS
AFTERN SUNRISE WED. DO NOT ANTICIPATE PREVAILING VISIBILITY
CONDITIONS AT ORD OR MDW TO BE BELOW MVFR THOUGH POSSIBLE IT MAY
DIP INTO HIGHER END OF IFR AROUND SUNRISE.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE IN LAKE BREEZE DEVELOPING AND AT LEAST MOVING
INTO THE VICINITY OF THE TERMINALS...MEDIUM CONFIDENCE ON
REACHING TERMINALS AND TURNING WINDS EASTERLY.
* MEDIUM CONFIDENCE IN WIDELY SCATTERED TSRA ESPECIALLY ALONG LAKE
BREEZE. LOW CONFIDENCE IN SPECIFIC IMPACTS TO TERMINALS.
* MEDIUM CONFIDENCE IN VSBY RESTRICTION EARLY WEDNESDAY MORNING.
BMD
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...MVFR VISIBILITY OVERNIGHT DUE TO BR HZ.
OTHERWISE...VFR...NO SIG WX.
THURSDAY...POSSIBLE MVFR VISIBILITY EARLY MORNING AND LATE
OVERNIGHT DUE TO BR HZ. OTHERWISE...VFR...NO SIG WX.
FRIDAY...INCREASING CHANCES OF TS AS DAY PROGRESSES...FROM SLIGHT
CHANCE IN THE MORNING TO CHANCE IN AFTERNOON AND LIKELY FRIDAY
NIGHT. ANY TSRA WOULD PRODUCE OF MVFR AND POSSIBLY BRIEF IFR
CONDITIONS.
SATURDAY...SLIGHT CHANCE OF TS. OTHERWISE VFR.
SUNDAY...VFR...NO SIG WX.
MONDAY...CHANCE OF TSRA...OTHERWISE VFR.
&&
.MARINE...
339 AM CDT
A LARGE AREA OF HIGH PRESSURE CENTERED OVER THE OH VALLEY EARLY
THIS MORNING WILL CONTINUE TO SLOWLY SHIFT TO THE W AND WILL BE
CENTERED IN THE MID MS VALLEY BY WED NIGHT MAINTAINING LIGHT TO
GENTLE S TO SW BREEZES ON THE LAKE. DURING THU AND THU NIGHT SW
WINDS WILL GRADUALLY FRESHEN AS A COLD FRONT DROPS S ACROSS THE
N WOODS AND LAKE SUPERIOR WHERE IT WILL WEAKEN. A STRONGER COLD
FRONT WILL DROP S OVER NORTHERN LAKE MI DURING FRI AFTERNOON
WITH THE COLD FRONT CONTINUING S DOWN THE LAKE REACHING THE S
END BY DAWN SAT. HIGH PRESSURE BUILDING SE FROM CENTRAL CANADA
TO THE UPPER MIDWEST DURING FRI NIGHT AND SAT WILL MAINTAIN
GENTLE TO MODERATE N TO NE BREEZES THROUGH THAT PERIOD.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
939 AM CDT TUE JUL 16 2013
.DISCUSSION...
939 AM CDT
GOING FORECAST LOOKS TO BE IN GOOD SHAPE WITH NO BIG CHANGES
PLANNED AT THIS TIME...JUST A SLIGHT UPWARD ADJUSTMENT TO POPS.
MORNING SOUNDINGS AGAIN TODAY WERE VERY MOIST IN THE LOW LEVELS
THOUGH SLIGHTLY DRIER ABOVE 700MB AS COMPARED WITH YESTERDAY. PWATS
ARE DOWN ABOUT A QUARTER TO A HALF INCH OR FROM YESTERDAY`S LEVELS
BUT REMAIN 150% OR MORE OF AVERAGE. STRONG UPPER RIDGE HAS SHIFTED
WEST A BIT FROM YESTERDAYS POSITION WITH 500MB HEIGHTS 20-30 METERS
HIGHER THAN YESTERDAY. MID LEVEL TEMPS REMAIN VERY WARM WITH WEAK
MID LEVEL LAPSE RATES...HOWEVER ILX/DVN MORNING RAOBS AND ACARS OUT
OF MDW THIS MORNING SHOW NO INVERSION OR POTENTIAL CAPPING LAYER. SO
WHILE WE DONT HAVE ANY SHORTWAVE ALOFT TO PROVIDE FORCING LIKE
YESTERDAY AND WHILE PWATS ARE DOWN A BIT...STILL THINK ISOLATED
CONVECTION IS A DECENT BET TODAY. BOTH THE RUC FORECAST SOUNDINGS
AND MODIFIED OBSERVED SOUNDINGS SUGGEST MLCAPE VALUES REACHING
3000-3500 J/KG WITH LITTLE/NO INHIBITION.
AS MENTIONED THERE IS NO FORCING ALOFT TODAY AS WE SIT PARKED ALMOST
DIRECTLY UNDER THE UPPER RIDGE...HOWEVER VWP SHOWS SOUTHWEST WINDS
OFF THE DECK DIMINISHING FROM THE NOCTURNAL MAXIMA AND THINK WE
SHOULD ONCE AGAIN SEE A LAKE BREEZE FORM THIS AFTERNOON. GIVEN THE
LOW LFC`S THE SHALLOW FORCING ALONG THE LAKE BREEZE WITH NO CAP
SHOULD ONCE AGAIN BE ENOUGH TO KICK OFF ISOLATED TO WIDELY SCATTERED
AFTERNOON THUNDERSTORMS. ALREADY SEEING VERY HEALTHY CUMULUS FIELD
BLOSSOMING NEAR THE CONVERGENCE ZONE DOWNTOWN...SO GIVEN THE SET UP
AM PLANNING TO BUMP UP POPS SOME TODAY OVER LAKE AND COOK COUNTIES
IN ILLINOIS LATE THIS MORNING INTO THE AFTERNOON. THE SLIGHTLY DRIER
AIR ALOFT TODAY ALONG WITH SLIGHTLY STRONGER INSTABILITY ACTUALLY
RAISES THE MICROBURST THREAT SOME OVER YESTERDAY AND THINK THE
THREAT OF A PULSE SEVERE THUNDERSTORM IS A BIT GREATER TODAY.
WILL GET SOME UPDATED GRIDS WITH SLIGHTLY HIGHER POPS OUT ALONG THE
LAKE BREEZE SHORTLY.
IZZI
&&
.PREV DISCUSSION...
337 AM CDT
FORECAST FOCUS REMAINS ON HEAT/HUMIDITY OVER THE NEXT SEVERAL
DAYS...AND POTENTIAL FOR ISOLATED THUNDERSTORMS AGAIN THIS
AFTERNOON. HEAT HEADLINES MAY BE REQUIRED LATER IN THE WEEK FOR
CONSECUTIVE DAYS OF PEAK HEAT INDICES ABOVE 100.
00Z RAOB ANALYSIS DEPICTS 6000 METER 500MB HEIGHTS AT ILN...WITH
UPPER LEVEL RIDGE EXPECTED TO DRIFT ACROSS NORTHERN INDIANA LATER
TODAY AND ACROSS CENTRAL IL ON WEDNESDAY...BEFORE GRADUALLY
WEAKENING AND SHIFTING SOUTH ACROSS THE LOWER OHIO VALLEY LATE IN IN
THE WEEK. 850MB TEMPS OF +18/19C SAMPLED BENEATH THE RIDGE...WITH
MODEL FORECASTS INDICATING THESE SLOWLY WARMING AS THE RIDGE DRIFTS
WEST...REACHING +20/21C BY FRIDAY AS THE RIDGE DRIFTS SOUTH AND
WEST-SOUTHWEST LOW LEVEL FLOW ENHANCES WARM ADVECTION OFF THE
PLAINS. TEMPS MONDAY WERE GENERALLY 89-91 OUTSIDE OF THE LAKE BREEZE
AND THUNDERSTORM EFFECTS...AND DIAGNOSIS OF LOW LEVEL THERMAL FIELDS
FROM MODELS INDICATE WE SHOULD BE PERHAPS A DEGREE OR SO HIGHER
OVERALL TODAY...AND IN THE LOW-MID 90S WED-FRI. COMBINED WITH SFC
DEW POINT TEMPERATURES GENERALLY IN THE LOWER 70S...THE COMBINATION
OF HEAT/HUMIDITY SHOULD YIELD AFTERNOON PEAK HEAT INDEX VALUES
ROUGHLY 98-102 DEGREES FOR THE NEXT FOUR DAYS. MUGGY CONDITIONS WITH
NIGHTTIME TEMPS SLOWLY FALLING THROUGH THE MID/UPPER 70S WILL NOT
PROVIDE MUCH RELIEF AT NIGHT EITHER. THREE TO FOUR CONSECUTIVE DAYS
OF THESE CONDITIONS WOULD REQUIRE HEAT HEADLINES FOR THE CWA. THE
CAVEATS AT THIS TIME HOWEVER REMAINS THE POTENTIAL FOR ISOLATED
AFTERNOON THUNDERSTORMS AGAIN TODAY (AND WED/THU AS WELL) AND A
GREATER THREAT OF THUNDERSTORMS FRIDAY AFTERNOON WHICH COULD DISRUPT
TEMPS/HEAT INDEX VALUES DURING PEAK HEATING...AS WELL AS LOWERING
DEW POINT TEMPERATURES DURING AFTERNOON MIXING. WILL HOLD OFF ON
HOISTING ANY HEADLINES FOR NOW...AND MONITOR HOW THINGS PLAY OUT
THIS AFTERNOON.
SHIFTING TO THUNDERSTORM POTENTIAL...FORECAST SOUNDINGS CONTINUE TO
DEPICT UNSTABLE AND FAIRLY UNCAPPED THERMODYNAMIC PROFILES ACROSS
THE AREA AGAIN THIS AFTERNOON. WHILE NOT MUCH SUPPORT NOTED ON THE
LARGE SCALE...LACK OF SIGNIFICANT CAPPING DOES SUGGEST THE POTENTIAL
FOR AT LEAST A FEW ISOLATED THUNDERSTORMS THIS AFTERNOON
PARTICULARLY ACROSS NORTHERN PARTS OF THE IL CWA...WITH CONVERGENCE
ALONG WEAK LAKE BREEZE A POTENTIAL TRIGGER. CONVECTIVE OUTFLOW
BOUNDARIES FROM ANY ISOLATED STORMS THAT DO FORM WOULD ALSO PROVIDE
FOCUS FOR ADDITIONAL ISOLATED DEVELOPMENT...WHICH SHOULD WANE TOWARD
EVENING WITH LOSS OF DIURNAL COMPONENT OF INSTABILITY. THOUGH SPARSE
IN NUMBER AND COVERAGE...ANY STORMS THAT WOULD FORM WOULD LIKELY BE
SLOW-MOVING AND POTENTIALLY HEAVY RAIN PRODUCERS...WITH 2.03 INCH
PWAT NOTED IN DVN 00Z RAOB AND 1.90 INCHES AT ILX. WHILE AN ISOLATED
THUNDERSTORM MAY ALSO BE POSSIBLE WEDNESDAY AND THURSDAY
AFTERNOON...THE POTENTIAL SHOULD BE DECREASING AS THE RIDGE DRIFTS
CLOSER AND MID-LEVEL TEMPERATURES WARM. ALSO...IT APPEARS AS THOUGH
THERE WILL BE JUST ENOUGH WEST-SOUTHWEST FLOW IN LOW LEVELS AFTER
TODAY TO PREVENT THE LAKE BREEZE FROM MOVING INLAND...PROVIDING LESS
FOCUS FOR CONVECTIVE INITIATION.
AS INDICATED ABOVE...THE UPPER RIDGE IS ANTICIPATED TO WEAKEN AND
MOVE SOUTH THURSDAY AND FRIDAY...WITH MID/UPPER LEVEL WESTERLIES
SETTLING ACROSS THE UPPER MIDWEST. MODEL GUIDANCE REMAINS IN GOOD
AGREEMENT THAT AMPLIFICATION OF AN UPPER TROUGH WILL OCCUR ACROSS
CENTRAL CANADA AND THE UPPER MIDWEST BY FRIDAY NIGHT...WITH A COLD
FRONT SAGGING SOUTH INTO OUR AREA. THUNDERSTORM POTENTIAL LOOKS TO
INCREASE FRIDAY AFTERNOON AHEAD OF THE FRONT...AS LARGE SCALE ASCENT
DEVELOPS IN ADVANCE OF THE DEEPENING UPPER TROUGH AND LOW LEVEL
CONVERGENCE AND MOISTURE POOLING OCCUR ALONG AND SOUTH OF THE COLD
FRONTAL BOUNDARY. SOME LINGERING THREAT OF SHOWERS/THUNDERSTORMS MAY
LINGER INTO SATURDAY AS THE FRONT CONTINUES TO SAG SOUTHWARD...
THOUGH MAINLY ACROSS THE SOUTH/SOUTHEASTERN PARTS OF THE CWA. COOLER
AND LESS HUMID WEATHER CAN BE EXPECTED HOWEVER...AS HIGH PRESSURE
BUILDS SOUTHEAST ACROSS THE GREAT LAKES OVER THE WEEKEND AND SHIFTS
WINDS TO THE NORTH-NORTHEAST. A RETURN TO WARMER AND MORE HUMID
CONDITIONS LOOKS TO TAKE PLACE AGAIN EARLY NEXT WEEK HOWEVER...WITH
THE ECMWF QUICKER WITH THE RETURN MONDAY.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* POSSIBILITY OF LAKE BREEZE REACHING FAR ENOUGH INLAND DURING THE
LATER AFTERNOON TO AFFECT WIND DIRECTION AT ORD/MDW.
* CHANCE OF TSRA THIS AFTERNOON ALONG LAKE BREEZE.
* VISIBILITY REDUCTION DUE TO BR AND HZ LATE TONIGHT THROUGH EARLY
WED MORNING.
TRS/BMD
//DISCUSSION...UPDATED 12Z...
VERY SLOW WESTWARD RETROGRESSION OF THE UPPER PATTERN ACROSS
THE EASTERN AND CENTRAL U.S WILL CONTINUE TODAY...THEN TO THE
WEST-SOUTHWEST TONIGHT. THE W TO E ELONGATED UPPER ANTICYCLONE
THAT CURRENTLY IS OVER FAR WESTERN LOWER MI IS TO RETREAT TO
AROUND THE CENTRAL PORTION OF THE IL-IN BOARDER BY LATE TONIGHT.
THE ASSOCIATED SURFACE HIGH CENTER IS ALSO DRIFTING WESTWARD
RESULTING IN THE LOW LEVEL FLOW OVER THE AREA BACKING FROM
SOUTHEASTERLY TO SOUTHWESTERLY OVERNIGHT PER WIND PROFILES FROM
WSR-88D NETWORK AS WELL AS TERMINAL DOPPLER INSTALLATIONS.
THIS SW FLOW WILL BE RATHER WEAK WITH PROGGED MIXED LAYER WINDS
OF ONLY UP TO AROUND 10 KT AT MOST DURING THE DAY. WHILE WEAK IT
IS EXPECTED TO LIMIT ANY LAKE BREEZE INLAND PENETRATION TO JUST
ALONG THE IMMEDIATE SHORELINES OF NW IN AND UP TO AROUND DOWNTOWN
CHICAGO...WITH DEEPER PENETRATION INLAND THE FURTHER ONES GOES
FROM THE LOOP N UP TO SE WI. EVEN MODELS THAT ARE MOST AGGRESSIVE
WITH THE LAKE BREEZE ONLY TAKE IT AS FAR W AS THE EASTERN BOARDER
OF THE ORD AIR FIELD SO THE TAFOR MAINTAINS SW SURFACE WINDS
THROUGH THE DAY.
WITH SOMEWHAT STAGNANT CONDITIONS UNDER THE ANTICYCLONE AN
INCREASE IN PARTICULATE MATTER AND COUPLED WITH DEW POINTS
REMAINING IN THE LOWER 70S IS EXPECTED TO RESULT IN VISIBILITY
BEING RESTRICTED BY SMOG FROM LATE OVERNIGHT TIL A COUPLE HOURS
AFTERN SUNRISE WED. DO NOT ANTICIPATE PREVAILING VISIBILITY
CONDITIONS AT ORD OR MDW TO BE BELOW MVFR THOUGH POSSIBLE IT MAY
DIP INTO HIGHER END OF IFR AROUND SUNRISE.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH CONFIDENCE IN LAKE BREEZE DEVELOPING AND AT LEAST MOVING
INTO THE VICINITY OF THE TERMINALS...LOW CONFIDENCE ON REACHING
TERMINALS.
* LOW TO MEDIUM CONFIDENCE IN ISOLATED/SCATTERED CONVECTION
DEVELOPING PARTICULARLY ALONG THE LAKE BREEZE.
* MODERATE CONFIDENCE IN VISIBILITY RESTRICTION OVERNIGHT AND
EARLY WED MORNING.
* HIGH CONFIDENCE ALL OTHER FORECAST PARAMETERS.
TRS/BMD
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...MVFR VISIBILITY OVERNIGHT DUE TO BR HZ.
OTHERWISE...VFR...NO SIG WX.
THURSDAY...POSSIBLE MVFR VISIBILITY EARLY MORNING AND LATE
OVERNIGHT DUE TO BR HZ. OTHERWISE...VFR...NO SIG WX.
FRIDAY...INCREASING CHANCES OF TS AS DAY PROGRESSES...FROM SLIGHT
CHANCE IN THE MORNING TO CHANCE IN AFTERNOON AND LIKELY FRIDAY
NIGHT. ANY TSRA WOULD PRODUCE OF MVFR AND POSSIBLY BRIEF IFR
CONDITIONS.
SATURDAY...SLIGHT CHANCE OF TS. OTHERWISE VFR.
SUNDAY...VFR...NO SIG WX.
MONDAY...CHANCE OF TSRA...OTHERWISE VFR.
&&
.MARINE...
339 AM CDT
A LARGE AREA OF HIGH PRESSURE CENTERED OVER THE OH VALLEY EARLY
THIS MORNING WILL CONTINUE TO SLOWLY SHIFT TO THE W AND WILL BE
CENTERED IN THE MID MS VALLEY BY WED NIGHT MAINTAINING LIGHT TO
GENTLE S TO SW BREEZES ON THE LAKE. DURING THU AND THU NIGHT SW
WINDS WILL GRADUALLY FRESHEN AS A COLD FRONT DROPS S ACROSS THE
N WOODS AND LAKE SUPERIOR WHERE IT WILL WEAKEN. A STRONGER COLD
FRONT WILL DROP S OVER NORTHERN LAKE MI DURING FRI AFTERNOON
WITH THE COLD FRONT CONTINUING S DOWN THE LAKE REACHING THE S
END BY DAWN SAT. HIGH PRESSURE BUILDING SE FROM CENTRAL CANADA
TO THE UPPER MIDWEST DURING FRI NIGHT AND SAT WILL MAINTAIN
GENTLE TO MODERATE N TO NE BREEZES THROUGH THAT PERIOD.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS DODGE CITY KS
333 PM CDT TUE JUL 16 2013
...UPDATE TO LONG TERM DISCUSSION...
.SYNOPSIS...
ISSUED AT 1201 PM CDT TUE JUL 16 2013
AT 12Z TUESDAY A 500MB LOW WAS LOCATED OVER EASTERN NEW MEXICO
AND A 500MB HIGH WAS LOCATED OVER THE OHIO VALLEY. ACROSS THE
SOUTHERN AND CENTRAL PLAINS A SOUTHEAST FLOW IN THE 850MB TO 500MB
LEVEL WAS DRAWING HIGHER DEWPOINTS INTO WESTERN KANSAS. ONE UPPER
LEVEL DISTURBANCE ROTATING AROUND THIS UPPER LOW WAS LOCATED
ACROSS THE PANHANDLE OF TEXAS AND WESTERN OKLAHOMA AS OF 12Z
TUESDAY WITH ANOTHER DISTURBANCE LOCATED NEAR THE BASED OF THIS
UPPER LOW ACROSS WESTERN TEXAS. WATER VAPOR LOOP AS OF 15Z
INDICATED THIS UPPER LOW WAS MOVING SLOWLY WESTWARD AS THE
PANHANDLE UPPER LEVEL WAVE APPROACHES SOUTHWEST KANSAS.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 159 PM CDT TUE JUL 16 2013
RAP AND WATER VAPOR LOOP INDICATING AN UPPER LEVEL DISTURBANCE
WAS MOVING NORTHWEST ACROSS THE PANHANDLE OF TEXAS AS OF 19Z WITH
RADAR TRENDS INDICATING PRECIPITATION INCREASING IN AREA COVER
AHEAD OF THIS DISTURBANCE ACROSS PORTIONS OF SOUTHWEST KANSAS. NAM
AND RAP WERE IN DECENT AGREEMENT IN MOVING THIS UPPER WAVE ACROSS
SOUTHWEST KANSAS INTO SOUTHEAST COLORADO EARLY TONIGHT. GIVEN THE
MOISTURE FORECAST ACROSS SOUTHWEST KANSAS IN THE 850MB TO 500MB
AHEAD OF THIS UPPER SYSTEM WILL RETAIN AT LEAST A CHANCE FOR
SHOWERS ACROSS SOUTHWEST KANSAS AT AROUND 03Z AND THEN TAPER
PRECIPITATION OFF FROM NORTHEAST TO SOUTHWEST.
AFTER MIDNIGHT SUBSIDENCE APPEARS TO DEVELOP ACROSS WESTERN KANSAS
AS THE UPPER LEVEL DISTURBANCE MOVES INTO SOUTHERN COLORADO.
CLEARING SKIES MAY BRIEFLY DEVELOP AFTER MIDNIGHT, HOWEVER SOME
EARLY MORNING STATUS AND/OR FOG WILL BE POSSIBLE AROUND DAYBREAK
GIVEN THE SHALLOW LAYER OF LOW LEVEL MOISTURE FORECAST BY THE 12Z
NAM. BASED ONE THE EXPECTED DEWPOINTS OVERNIGHT THE PREVIOUS
FORECAST WITH LOWS RANGING FROM 60 TO NEAR 65 DEGREES STILL LOOKS
ON TRACK.
ON WEDNESDAY A TROUGH OF LOW PRESSURE WILL DEEPEN ALONG THE LEE
OF THE ROCKIES. BASED ON EXPECTED SKY COVER AND 00Z 850MB
TEMPERATURES RANGING FROM AROUND 20 IN SOUTH CENTRAL KANSAS TO THE
MID 20S NEAR THE COLORADO BORDER HAVE DECIDED TO TREND TOWARDS THE
SLIGHTLY COOLER ECMWF GUIDANCE FOR HIGHS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 333 PM CDT TUE JUL 16 2013
WEDNESDAY NIGHT:
LEE TROUGHING WILL CONTINUE WEDNESDAY NIGHT INTO THURSDAY MORNING.
THE UPPER LEVEL DISTURBANCE MENTIONED IN THE SYNOPSIS/SHORT TERM PERIOD
WILL CONTINUE TO DRIFT WELL AWAY FROM THE REGION BY THURSDAY MORNING.
STILL, THERE WILL BE "COOLER" LOW TO MID LEVEL TEMPERATURES ASSOCIATED
WITH THE PRESSURE PERTURBATION LINGERING ACROSS THE REGION. CONSIDERING
THIS AND THE WARM BIAS SHOWN VIA BOISE VERIFICATION...HAVE GONE WITH
COOLER MOS GUIDANCE FOR MINIMUMS INTO THURSDAY MORNING...60S DEG F.
THURSDAY:
ON THURSDAY, THE AFOREMENTIONED LEE SURFACE TROUGH WILL CONTINUE TO
DEEPEN AHEAD OF A TRAVERSING SHORTWAVE TROF ACROSS THE NORTHERN PLAINS.
THIS WILL ALLOW FOR A CONTINUED WARM AIR ADVECTION REGIME THROUGH THE
DAY. HAVE GONE WITH COOLER ECMWF RAW OUTPUT FOR MAXIMUMS - MID 90S DEG
F NORTHEAST TO AROUND 90 DEG F SOUTHWEST. NO PRECIPITATION IS EXPECTED
THROUGH THE DAY WITH PRECIPITATION PROBABILITY PERCENTAGE POINTS AOB
10 PERCENT AS THE AFOREMENTIONED SYNOPTIC SYSTEM IS WELL TO THE NORTH.
FRIDAY AND BEYOND:
A MODERATION OF TEMPERATURES IS EXPECTED WITH MAXIMUMS IN THE 90S DEG
F AND LOWS IN THE 60S AND 70S DEG F AS LEE TROUGHING CONTINUES AHEAD
OF AN APPROACHING COLD FRONT. THIS FRONT SHOULD BE IN THE REGION (PER
ECMWF) SOMETIME LATE FRIDAY NIGHT AND INTO SATURDAY. CONVECTION WILL
BE POSSIBLE ALONG THIS DENSITY GRADIENT THROUGH THE WEEKEND. THE 12Z
ECMWF SOLUTION HAS TRENDED DRIER THAN COMPARED TO THE 00Z ECMWF SOLUTION.
THE GFS, AS PER USUAL, IS WETTER AND COOLER THAN COMPARED TO THE EC.
DUE TO THE UNCERTAINTY, WILL GO WITH THE ALLBLEND SOLUTION FOR NOW.
THIS MODEL - OF COURSE - APPLIES A WEIGHTING FUNCTION TO BOTH SOLUTIONS
PLUS THE PREVIOUS NDFD GRIDS. BEYOND THIS, 500 HPA RIDGING IS INDICATED
BY BOTH MODELS BY EARLY TO MID WEEK OF NEXT WEEK, WHICH FAVORS A DRY
FORECAST AND HOT TEMPERATURES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1201 PM CDT TUE JUL 16 2013
DDC 12Z SOUNDING, UPPER AIR ANALYSIS AND NAM BUFR SOUNDINGS
INDICATING A FAIRLY DEEP LAYER OF MOISTURE WILL BE PRESENT THROUGH
EARLY TONIGHT AT DDC AND GCK. AS A RESULT CLOUD BASES WILL
IMPROVE, HOWEVER MVFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH
AT LEAST 00Z WEDNESDAY. THE EXCEPTION WILL BE HAYS WERE BUFR
SOUNDINGS INDICATED VFR CONDITIONS WILL BE LIKELY THIS AFTERNOON
AND EARLY TONIGHT. THERE WILL ALSO BE A CHANCE FOR SHOWERS THIS
AFTERNOON AND EARLY TONIGHT, MAINLY IN THE GCK AND DDC AREA AS AN
UPPER LEVEL DISTURBANCE ROTATES AROUND AN UPPER LOW THAT WILL BE
LOCATED ACROSS EASTERN NEW MEXICO. SOUTHEAST WINDS AT AROUND 15KTS
WILL DECREASE TO 10KTS OR LESS AFTER SUNSET.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 62 87 65 91 / 40 10 10 0
GCK 60 86 64 90 / 50 10 10 10
EHA 59 82 62 88 / 50 10 10 10
LBL 62 84 64 89 / 60 10 10 10
HYS 63 89 67 94 / 20 10 0 0
P28 65 87 68 91 / 30 20 10 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BURGERT
SHORT TERM...BURGERT
LONG TERM...3.14
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
205 PM CDT TUE JUL 16 2013
...UPDATED SHORT TERM DISCUSSION...
.SYNOPSIS...
ISSUED AT 1201 PM CDT TUE JUL 16 2013
AT 12Z TUESDAY A 500MB LOW WAS LOCATED OVER EASTERN NEW MEXICO
AND A 500MB HIGH WAS LOCATED OVER THE OHIO VALLEY. ACROSS THE
SOUTHERN AND CENTRAL PLAINS A SOUTHEAST FLOW IN THE 850MB TO 500MB
LEVEL WAS DRAWING HIGHER DEWPOINTS INTO WESTERN KANSAS. ONE UPPER
LEVEL DISTURBANCE ROTATING AROUND THIS UPPER LOW WAS LOCATED
ACROSS THE PANHANDLE OF TEXAS AND WESTERN OKLAHOMA AS OF 12Z
TUESDAY WITH ANOTHER DISTURBANCE LOCATED NEAR THE BASED OF THIS
UPPER LOW ACROSS WESTERN TEXAS. WATER VAPOR LOOP AS OF 15Z
INDICATED THIS UPPER LOW WAS MOVING SLOWLY WESTWARD AS THE
PANHANDLE UPPER LEVEL WAVE APPROACHES SOUTHWEST KANSAS.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 159 PM CDT TUE JUL 16 2013
RAP AND WATER VAPOR LOOP INDICATING AN UPPER LEVEL DISTURBANCE
WAS MOVING NORTHWEST ACROSS THE PANHANDLE OF TEXAS AS OF 19Z WITH
RADAR TRENDS INDICATING PRECIPITATION INCREASING IN AREA COVER
AHEAD OF THIS DISTURBANCE ACROSS PORTIONS OF SOUTHWEST KANSAS. NAM
AND RAP WERE IN DECENT AGREEMENT IN MOVING THIS UPPER WAVE ACROSS
SOUTHWEST KANSAS INTO SOUTHEAST COLORADO EARLY TONIGHT. GIVEN THE
MOISTURE FORECAST ACROSS SOUTHWEST KANSAS IN THE 850MB TO 500MB
AHEAD OF THIS UPPER SYSTEM WILL RETAIN AT LEAST A CHANCE FOR
SHOWERS ACROSS SOUTHWEST KANSAS AT AROUND 03Z AND THEN TAPER
PRECIPITATION OFF FROM NORTHEAST TO SOUTHWEST.
AFTER MIDNIGHT SUBSIDENCE APPEARS TO DEVELOP ACROSS WESTERN KANSAS
AS THE UPPER LEVEL DISTURBANCE MOVES INTO SOUTHERN COLORADO.
CLEARING SKIES MAY BRIEFLY DEVELOP AFTER MIDNIGHT, HOWEVER SOME
EARLY MORNING STATUS AND/OR FOG WILL BE POSSIBLE AROUND DAYBREAK
GIVEN THE SHALLOW LAYER OF LOW LEVEL MOISTURE FORECAST BY THE 12Z
NAM. BASED ONE THE EXPECTED DEWPOINTS OVERNIGHT THE PREVIOUS
FORECAST WITH LOWS RANGING FROM 60 TO NEAR 65 DEGREES STILL LOOKS
ON TRACK.
ON WEDNESDAY A TROUGH OF LOW PRESSURE WILL DEEPEN ALONG THE LEE
OF THE ROCKIES. BASED ON EXPECTED SKY COVER AND 00Z 850MB
TEMPERATURES RANGING FROM AROUND 20 IN SOUTH CENTRAL KANSAS TO THE
MID 20S NEAR THE COLORADO BORDER HAVE DECIDED TO TREND TOWARDS THE
SLIGHTLY COOLER ECMWF GUIDANCE FOR HIGHS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 350 AM CDT TUE JUL 16 2013
UPPER LEVEL RIDGING WILL STRENGTHEN OVER THE CENTRAL PLAINS
WEDNESDAY INTO THURSDAY, WITH LITTLE OR NO PRECIPITATION AND HIGH
TEMPERATURES RISING INTO THE 80S TO NEAR 90F WEDNESDAY AND INTO THE
90S BY THURSDAY. A LEFTOVER SHOWER OR TWO CANNOT BE COMPLETELY
RULED OUT WEDNESDAY IN SOUTHERN KANSAS SINCE THE MID LEVEL FLOW
WILL STILL BE SOUTHEASTERLY, WITH CONTINUED LOW TO MID LEVEL
MOISTURE INFLUX. A LEE TROUGH WILL BE IN PLACE ACROSS THE HIGH
PLAINS IN RESPONSE TO ZONAL MID LEVEL FLOW ACROSS THE NORTHERN
ROCKIES, LEADING TO SOUTH WINDS EACH DAY.
UPPER LEVEL TROUGHING WILL PROGRESS SOUTHEASTWARD THROUGH THE GREAT
LAKES BY FRIDAY, ALLOWING A COLD FRONT TO PUSH INTO NORTHWEST KANSAS
FRIDAY AFTERNOON AND THEN STALL OUT OVER KANSAS/OKLAHOMA BY
SATURDAY. THIS WILL SET THE STAGE FOR CHANCES OF SHOWERS AND
THUNDERSTORMS FROM LATE FRIDAY INTO SUNDAY GIVEN THAT THERE SHOULD
BE SUFFICIENT MOISTURE (DEWPOINTS IN THE 60S) FOR THUNDERSTORM
ACTIVITY. HIGH TEMPERATURES WILL BE IN THE MID 90S FRIDAY AHEAD OF
THE FRONT, BUT ONLY NEAR 90 OR THE LOWER 90S SATURDAY AND SUNDAY
DUE TO EXPECTED CLOUD COVER AND POSSIBLE PRECIPITATION.
TEMPERATURES MAY WARM BACK UP EARLY TO MID NEXT WEEK (UPPER 90S TO
NEAR 100F) AS UPPER LEVEL TROUGHING DEVELOPS OVER THE NORTHERN
ROCKIES OR ALONG THE WEST COAST, WITH RIDGING ACROSS THE CENTRAL
PLAINS. ALTHOUGH ISOLATED THUNDERSTORMS CANNOT BE RULED OUT,
PRECIPITATION CHANCES LOOK VERY LOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1201 PM CDT TUE JUL 16 2013
DDC 12Z SOUNDING, UPPER AIR ANALYSIS AND NAM BUFR SOUNDINGS
INDICATING A FAIRLY DEEP LAYER OF MOISTURE WILL BE PRESENT THROUGH
EARLY TONIGHT AT DDC AND GCK. AS A RESULT CLOUD BASES WILL
IMPROVE, HOWEVER MVFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH
AT LEAST 00Z WEDNESDAY. THE EXCEPTION WILL BE HAYS WERE BUFR
SOUNDINGS INDICATED VFR CONDITIONS WILL BE LIKELY THIS AFTERNOON
AND EARLY TONIGHT. THERE WILL ALSO BE A CHANCE FOR SHOWERS THIS
AFTERNOON AND EARLY TONIGHT, MAINLY IN THE GCK AND DDC AREA AS AN
UPPER LEVEL DISTURBANCE ROTATES AROUND AN UPPER LOW THAT WILL BE
LOCATED ACROSS EASTERN NEW MEXICO. SOUTHEAST WINDS AT AROUND 15KTS
WILL DECREASE TO 10KTS OR LESS AFTER SUNSET.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 62 87 65 92 / 20 10 10 0
GCK 60 87 64 92 / 20 10 0 0
EHA 59 84 64 90 / 30 10 10 10
LBL 62 85 64 91 / 20 10 10 0
HYS 63 91 67 94 / 10 10 10 0
P28 65 88 68 92 / 20 20 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BURGERT
SHORT TERM...BURGERT
LONG TERM...FINCH
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1201 AM MDT TUE JUL 16 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 138 PM MDT MON JUL 15 2013
LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOW 581 DM CLOSED LOW
CENTERED OVER SW OKLAHOMA...WITH A 599 DM RIDGE ACROSS THE EASTERN
CONUS EXTENDING WEST ACROSS THE NORTHERN PLAINS. WV IMAGERY SHOWS
MOISTURE CONTINUING TO ROTATE AROUND EASTERN EXTEND OF CLOSED LOW
INTO SOUTHERN KS. RAP/LATEST NAM SHOW A CURVED JET STRUCTURE ACROSS
THE NORTHERN PART OF CLOSED LOW OVER SW KS AND SEVERAL VORT MAXES
ROTATING THROUGH THE NORTHERN EXTENT OF THIS LOW. COMPOSITE RADAR
SHOWS SHOWER ACTIVITY HAVING DEVELOPED WITH THESE FEATURES MOVING TO
ACROSS CENTRAL AND SOUTHWEST KANSAS. VIS SATELLITE SHOWS A
WIDESPREAD CU FIELD IN PLACE ACROSS OUR CWA THAT HAS DEVELOPED WITH
DAYTIME HEATING AND COLD POOL ALOFT.
LATEST SHORT RANGE GUIDANCE SHOWS THE ACTIVITY CURRENTLY SOUTH AND
EAST OF THE CWA FALLING APART BY 00Z AS IT MOVES TOWARDS OUR CWA. AT
THIS POINT I AM NOT SURE WE WILL ACTUALLY SEE ANY SHOWERS DEVELOP
WITH CU FIELD...THOUGH UNTIL WE LOOSE DAYTIME HEATING I COULDNT RULE
OUT SHOWERS SPREADING INTO THE SOUTHERN HALF CONSIDERING RADAR
TRENDS...AND AT LEAST SOME LARGE SCALE FORCING STILL IN PLACE JUST TO
OUR SOUTH. I DO NOT EXPECT THIS TO BE WIDESPREAD AND SHOULD QUICKLY
END AS WE LOOSE FAVORABLE LOW LEVEL LAPSE RATES DUE TO DIURNAL
COOLING.
SOUTHERLY FLOW WILL KEEP BL MOISTURE IN PLACE OVERNIGHT AND
TUESDAY...AND THERE IS SOME INDICATION OF A FEW SHOWERS ACROSS
SOUTHERN KS...POSSIBLY INTO OUR CWA AS UPPER LOW CONTINUES TO SLOWLY
MOVE WEST. WITH LITTLE IN THE WAY OF INSTABILITY AND STRONG
SUBSIDENCE BUILDING IN FROM THE NORTH TONIGHT I DECIDED TO KEEP
FORECAST DRY. WE DO BEGIN TO SEE A SIMILAR SET UP AS THIS AFTERNOON
REGARDING INCREASING LAPSE RATES BELOW COLD POOL...HOWEVER WITH
RIDGE BEGINNING TO HOLD MORE INFLUENCE AND DRIER AIR MOVING INTO THE
REGION ALOFT...I DECIDED TO KEEP POPS SILENT FOR NOW. I DID KEEP
PATCHY FOG MENTION IN THE FORECAST FOR TUESDAY MORNING...AND GOOD BL
MOISTURE ADVECTING IN FROM THE SOUTH. WITH BL WINDS
INCREASING...IF WE SEE SURFACE WINDS AROUND 10KT THE LOW LEVELS
MAY BE TOO MIXED FOR FOG DEVELOPMENT...SO I KEPT COVERAGE PATCHY.
THERE IS LITTLE CHANGE REGARDING THE AIR MASS OVER OUR CWA
TUESDAY...AND THERE ARE SIMILAR TRENDS REGARDING CLOUD COVER. TEMPS
ON TUESDAY SHOULD BE VERY SIMILAR TO TODAY...WITH HIGHS RANGING FROM
THE UPPER 70S WEST TO UPPER 80S EAST.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 244 PM MDT MON JUL 15 2013
DRY CONDITIONS WITH A SLOW WARMING TREND WILL BE THE DOMINANT
WEATHER PATTERN UNTIL THE OF THE WEEK AS THE HIGH PRESSURE OVER THE
EASTERN CONUS MOVES WEST TOWARD THE ROCKIES. WEDNESDAY AND THURSDAY
WILL BE WINDY AS 850MB WINDS NEAR 30KTS ARE ABLE TO MIX DOWN TO
THE GROUND AHEAD OF THE RETROGRADING RIDGE. PRECIPITATION CHANCES
RETURN FRIDAY THROUGH EARLY NEXT WEEK AS A FEW UPPER LEVEL
DISTURBANCES MOVE THROUGH THE NORTHWEST FLOW OVER THE AREA.
FRIDAY A WEAK FRONT/SURFACE TROUGH MOVES OVER THE AREA...COOLING THE
ABOVE NORMAL TEMPERATURES DOWN AND HELPING WITH PRECIP. CHANCES AS
AN UPPER LEVEL TROUGH ALSO MOVES THROUGH.
THE WEAK FRONT LINGERS OVER THE SOUTHERN PART OF THE AREA THROUGH
SATURDAY WHICH MAY AID IN CREATING SOME STORMS FOR THE AREA.
PRECIPITATION CHANCES LINGER THROUGH EARLY NEXT WEAK AS ANOTHER WEAK
UPPER LEVEL TROUGH MOVES ACROSS THE AREA.
TEMPERATURES THROUGH THE PERIOD WILL START OUT NEAR NORMAL THEN WARM
TO NEAR/ABOVE NORMAL BY THE WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1151 PM MDT MON JUL 15 2013
EXPECT MOSTLY VFR CONDITIONS TO PREVAIL AT MCK AND GLD SITES
THROUGH THE TAF PERIOD. BUT WITH LOW 60S DEWPOINT AIR STREAMING
IN AT THE SURFACE AND OVERNIGHT LOW TEMPERATURES EXPECTED TO BE
NEAR CURRENT DEWPOINTS ACROSS THE REGION...EXPECT MVFR CONDITIONS
DUE PRIMARILY TO A LOW CLOUDS DECK THAT BECOME MORE WIDESPREAD
ACROSS THE CENTRAL HIGH PLAINS REGION OVERNIGHT. AS WIND SPEEDS
DECREASE TOWARDS SUNRISE...COULD SEE SOME PATCHY FOG ALSO
DEVELOPING. EXPECT WINDS TO BE SSE...BUT IF THEY TURN TO HAVE A
MORE EASTERLY COMPONENT...COULD SEE IFR CONDITIONS WITH VISIBILITIES
DECREASING TO A MILE OR LESS DUE TO MORE WIDESPREAD FOG. WITH
CURRENT WIND DIRECTION AND SPEED FORECAST...HAVE KEPT CONDITIONS
MVFR BETWEEN 10Z-14Z AT BOTH MCK AND GLD WITH TEMPORARY 3SM
VISIBILITY AND A BROKEN CLOUD LAYER AT 015 AGL. GUSTY SOUTH TO
SOUTHEAST WINDS WILL RETURN BY MID MORNING...DISSIPATING ANY FOG
AND LOWER CLOUDS THROUGH THE DAY WITH A SCATTERED HIGHER CUMULUS
LAYER DEVELOPING DURING THE AFTERNOON.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JTL
AVIATION...LOCKHART
AREA FORECAST DISCUSSION
NWS GRAY ME
934 PM EDT WED JUL 17 2013
.SYNOPSIS...
A WEAK COLD FRONT WILL SLOWLY CROSS NORTHERN MAINE TONIGHT...
PRODUCING A TREAT FOR SHOWERS AND THUNDERSTORMS. THE FRONT WILL
PUSH BACK TO THE NORTH ON THURSDAY...MAKING FOR A RETURN TO HOT
AND HUMID WEATHER ON FRIDAY. A COLD FRONT WILL DROP SOUTH FROM
CANADA FRIDAY NIGHT AND WILL CROSS THE REGION ON
SATURDAY...POSSIBLY SETTING OFF A ROUND OF STRONG TO SEVERE
THUNDERSTORMS. COOLER AND LESS HUMID HIGH PRESSURE BUILDS IN ON
SUNDAY AND LINGERS INTO EARLY NEXT WEEK...BEFORE THINGS START
SHOW SIGNS OF WARMING UP AGAIN.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
WILL UPDATE TO ADJUST THE CHANCE OF SHOWERS AND THUNDERSTORMS
THIS EVENING PER LATEST RADAR MOSAIC LOOP. STILL EXPECTING
CONVECTIVE ACTIVITY TO MOVE THROUGH DURING THE COURSE OF THE
EVENING HOURS. ANY OTHER CHANGES VERY MINIMAL AT THIS TIME.
ZONES UPDATED TO ADD THE SEVERE THUNDERSTORM WATCH THROUGH
MIDNIGHT TONIGHT. ALREADY HAVE POSSIBLE SEVERE THUNDERSTORMS IN
THE FORECAST FOR THIS EVENING.
SHOWERS AND THUNDERSTORMS DEVELOPING OVER ONTARIO WILL MOVE
SOUTHEAST AND INTO NORTHERN NEW ENGLAND TONIGHT. THIS ACTIVITY
WILL BE PRIMARILY DRIVEN BY A SHORTWAVE TROUGH AND SURFACE COLD
FRONT INTERACTING WITH A VERY WARM/MOIST PRE-FRONTAL ENVIRONMENT.
HRRR MODEL SEEMS TO BE HANDLING THE FORECAST VERY WELL TODAY AND
THIS WAS USED EXTENSIVELY IN THE NEAR TERM FORECAST FOR TONIGHT.
AS COORDINATED WITH THE STORM PREDICTION CENTER... IT APPEARS THAT
INITIALLY ISOLATED CONVECTIVE ACTIVITY OVER CANADA AND UPSTATE NEW
YORK WILL LIKELY EVOLVE INTO A SQUALL LINE AND MOVE SOUTHEAST
THROUGH VERMONT AND NEW HAMPSHIRE AND INTO MAINE. HRRR MODEL SEEMS
TO BE SHOWING THE SIGNS OF AN MESOSCALE CONVECTIVE SYSTEM WITH
TRAILING STRATIFORM RAIN REGION BEHIND IT ARRIVING IN NEW
HAMPSHIRE AROUND 7 TO 8 PM AND HOLDING TOGETHER ALL THE WAY TO THE
COAST BY MIDNIGHT. DAMAGING WINDS WILL BE THE BIGGEST THREAT WITH
THIS SCENARIO TONIGHT... ALTHOUGH VERY MOIST ENVIRONMENT WILL
ALLOW FOR EFFICIENT RAINFALL PRODUCTION. WIDESPREAD RAINFALL OF
OVER ONE INCH ARE POSSIBLE WITH THE LEADING CONVECTIVE BAND AND
TRAILING RAIN REGION.
STORMS SHOULD MOVE OFF THE COAST AROUND MIDNIGHT... WITH CLEARING
BEHIND IT. COULD SEE SOME FOG ESPECIALLY IF RAIN IS WIDESPREAD.
HUMIDITY WILL KEEP TEMPERATURES IN THE UPPER 60S AND LOW 70S.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
COLD FRONT / OUTFLOW FROM OVERNIGHT CONVECTION WILL STALL AND WASH
OUT OFFSHORE ON THURSDAY. MAY SEE A RETURN FLOW OF WARM/MOIST AIR
INTO THE AREA WITH TEMPERATURES WARMING INTO THE UPPER 80S AND LOW
90S. DEW POINTS NEAR 70 WILL ALLOW HEAT INDEX VALUES TO RISE INTO
THE UPPER 90S. DO NOT ANTICIPATE NEEDING A HEAT ADVISORY FOR
THURSDAY AS THERE WILL NOT BE A LARGE AREA OF EXTENDED HEAT INDEX
READINGS ABOVE 100. IF HIGHER DEW POINTS OR HIGHER TEMPERATURES
ARE ACHIEVED... THEN THIS CRITERIA COULD BE MET. CONDITIONS WILL
BE CLOSE TO ADVISORY CRITERIA... BUT CONSIDERING THAT THE HOT AND
HUMID WEATHER HAS BEEN AROUND FOR SEVERAL WEEKS THIS SUMMER... DID
NOT THINK A MARGINAL ADVISORY WAS NEEDED AS THE AWARENESS OF THE
HOT AND HUMID WEATHER IS ALREADY HIGH.
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE DURING THE AFTERNOON
TOMORROW... PRIMARILY OVER THE SOUTHWESTERN HALF OF THE AREA WHERE
BETTER INSTABILITY EXISTS. A SHORTWAVE TROUGH WILL ALSO ADD LIFT
IN THIS AREA TO INCREASE THE CHANCE OF CONVECTION. ALTHOUGH WE
CANNOT RULE OUT THE THREAT FOR DAMAGING WINDS WITH ANY STORMS THAT
FORM... THE THREAT DOES NOT APPEAR WIDESPREAD.
EXPECT SHOWERS AND THUNDERSTORMS TO DISSIPATE THURSDAY EVENING.
ANOTHER HUMID NIGHT WILL KEEP TEMPERATURES IN THE UPPER 60S AND
LOW 70S.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
500 MB HEIGHTS RISE ON FRIDAY AS RIDGING BUILDS IN BRIEFLY...AND
850 TEMPS APPROACH 20 C. EXPECTING THIS BE ONE OF THE MORE HOT AND
HUMID DAYS WE HAVE SEEN THIS SUMMER...AND HEAT INDEX VALUES WILL
LIKELY REACH 100 IN PARTS OF THE SOUTHERN ZONES...AND A HEAT
ADVISORY MAY BE NEEDED THERE. CANNOT RULE OUT A FEW AIR MASS
THUNDERSTORMS...BUT BETTER CHANCE WILL BE IN NORTHERN
ZONES...WHERE STRONGER WINDS ALOFT...AND APPROACHING COLD FRONT
WILL CREATE BETTER DYNAMICS...AND COULD PRODUCE SOME STRONGER
STORMS. LOOK FOR A WARM AND UNCOMFORTABLE NIGHT FRIDAY NIGHT AS
HUMIDITIES REMAIN HIGH AND INCREASED SW FLOW PREVENTS MIN FROM
DROPPING OFF MUCH. COLD FRONT WILL APPROACH NORTHERN ZONES LATE
FRIDAY NIGHT...AND THE THREAT FOR THUNDERSTORMS WILL INCREASE
TOWARD DAYBREAK...AND SHIFT SOUTHWARD TOWARD THROUGH THE DAY.
GIVEN THE GREAT SURFACE INSTABILITY AND THE STRONG MID-UPPER LEVEL
WINDS DROPPING SOUTHWARD AHEAD OF THE FRONT SATURDAY...THE THREAT
FOR SEVERE CONVECTION REMAINS A CONCERN ON SATURDAY...AND THIS
COULD LINGER INTO THE EVENING.
THE FRONT IS EXPECTED TO CLEAR THE COAST LATE SATURDAY NIGHT OR
EARLY SUNDAY...WITH CLEARING AND NOTICEABLY COOLER AND LESS
HUMID CONDITIONS. THE HIGH THAT BUILDS IN BEHIND THE FRONT WILL
LINGER INTO TUESDAY...WITH TEMPS CLOSE TO OR A LITTLE BELOW NORMAL
DURING THIS PERIOD. AN INCREASE IN HUMIDITY AND TEMPS IS POSSIBLE
BY MID-WEEK.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
SHORT TERM /THROUGH THURSDAY NIGHT/...SCATTERED WITH POSSIBLY MORE
NUMEROUS SHOWERS AND THUNDERSTORMS MOVE THROUGH OVERNIGHT, MAINLY
THIS EVENING, WITH POSSIBLE IFR CIG/VSBY. SHOWERS AND THUNDERSTORMS
END FROM NW TO SE FROM ROUGHLY 04Z TO 06Z. POSSIBLE SEVERE WX WITH
THUNDERSTORMS WITH A SEVERE THUNDERSTORM WATCH IN EFFECT THROUGH
MIDNIGHT ACROSS THE MOUNTAINS AND FOOTHILLS OF WESTERN MAINE AND
ALL OF NEW HAMPSHIRE EXCEPT SOUTHEAST PORTIONS. VALLEY FOG WITH
POSSIBLE IFR/LIFR CIG/VSBY FORMS OVERNIGHT MAINLY WHERE RAIN HAS
FALLEN AND IN MORE FAVORABLE LOCATIONS. VFR THURSDAY AND THURSDAY
NIGHT...EXCEPT LOWER IN SCATTERED AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS. AGAIN...PATCHY FOG POSSIBLE THURSDAY NIGHT.
LONG TERM...MAINLY VFR FRIDAY AND FRIDAY NIGHT...WITH FLIGHT
RESTRICTIONS IS CONVECTION EXPECTED ON SATURDAY INTO SATURDAY
EVENING. VFR RETURNS SUNDAY AND MONDAY.
&&
.MARINE...
SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...WILL UPDATE AGAIN PER
LATEST BUOY OBSERVATIONS WITH MINIMAL, IF ANY, CHANGES TO THE
PREVIOUS FCST OTHER THAN TO ADD GUSTY WINDS, ABRUPT WIND SHIFTS
AND NEAR ZERO VSBY POSSIBLE WITH TSTMS OVERNIGHT. A FEW GUSTS UP
TO 25 KT AT THIS TIME WILL CONTINUE THROUGH THE EVENING HOURS BUT
WON`T BE FREQUENT ENOUGH TO WARRANT AN SCA. WINDS DROP OFF
OVERNIGHT. WILL HOLD SEAS BELOW 5 FEET OVERNIGHT AS THEY TRY TO
BUILD THIS EVENING BUT SLACKEN OFF OVERNIGHT AS WINDS LET UP.
WINDS AND SEAS STAY BELOW SCA LEVELS THURSDAY AND THURSDAY NIGHT.
LONG TERM...SW FLOW INCREASES AHEAD OF A COLD FRONT FRIDAY NIGHT
INTO SATURDAY WITH SEAS IN EXCESS AROUND 5 FT...AND WINDS APPROACHING
SCA LEVELS. WINDS WILL SHIFT TO NW SATURDAY NIGHT AND DIMINISH.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
622 AM EDT TUE JUL 16 2013
.SYNOPSIS...
HIGH PRESSURE ANCHORED OVER THE MIDWEST AND EXTENDING INTO NEW
ENGLAND WILL PROVIDE CONTINUED WARM SUMMERTIME TEMPERATURES. A
SERIES OF SHORTWAVES RIPPLING ACROSS THE CANADIAN BORDER THROUGH
FRIDAY WILL PROVIDE INCREASING CHANCES FOR SHOWERS AND
THUNDERSTORMS. A VIGOROUS FRONT WILL CROSS THE AREA ON SATURDAY,
BRINGING A RESPITE FROM THE HEAT SUNDAY AND MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
620 AM UPDATE...06 UTC NAM AND 09 UTC RAP SHOWING WEAKER FORCING
THIS AFTERNOON FOR CONVECTION ALONG THE WEAK BOUNDARY TO DRAPE
ACROSS NEW ENGLAND THIS AFTERNOON. HAVE CUT ALL AFTERNOON POPS TO
LESS THAN 30 PERCENT. OTHERWISE JUST A FEW TWEAKS TO MATCH CURRENT
OBSERVATIONS.
402 AM ISSUANCE...CLEAR SKIES THIS MORNING WILL GIVE WAY TO SOME SCATTERED
CUMULUS DEVELOPMENT, ESPECIALLY OVER THE HIGHER TERRAIN. RAP/NAM
SHOWING A BOUNDARY SET TO BE LYING FROM SOUTHERN QUEBEC THROUGH
EASTERN NEW HAMPSHIRE THIS AFTERNOON. FEATURE IS PRETTY SUBTLE AND
MAY NOT BE ENOUGH TO FIRE CONVECTION, BUT HAVE ADDED ISOLATED
THUNDER THIS AFTERNOON AND EVENING ACROSS MOSTLY INTERIOR EASTERN
NEW HAMPSHIRE AND SOUTHWEST MAINE. HOT AGAIN TODAY WITH HIGHS FROM
THE MID 80S TO LOWER 90S AND CONTINUED DEW POINT TEMPERATURES IN
THE MID 60S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
SOME VALLEY FOG IS EXPECTED TONIGHT AS DEW POINTS CLIMB SLIGHTLY.
TEMPERATURES WILL BOTTOM OUT AGAIN IN THE 60S IN MOST LOCATIONS. A
SHORTWAVE WILL THEN APPROACH THE AREA ON WEDNESDAY AFTERNOON.
PRECIPITABLE WATER VALUES ARE FORECAST TO APPROACH 2 STANDARD
DEVIATIONS ABOVE NORMAL, PLUS FORCING TRIGGERED BY THE SHORTWAVE
AND AMPLE BULK SHEAR AND BUOYANCY WILL PROVIDE THE THREAT FOR
SEVERE CONVECTION -- ESPECIALLY ALONG THE CANADIAN BORDER. HIGHS
ARE EXPECTED TO BE 1-3F COOLER ON WEDNESDAY COMPARED TO TODAY`S
FORECAST HIGHS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
SFC BOUNDARY ATTENDANT TO S/WV TROF WILL SLOWLY SAG SWD THRU THE
CWFA WED NIGHT INTO THU. IT WILL REMAIN A FOCUS FOR SHRA AND TSTMS
OVERNIGHT...AND AGAIN WITH DIURNAL HEATING ON THU. STRONG
INSOLATION IN A MOIST ENVIRONMENT WILL PROVIDE PLENTY OF
INSTABILITY FOR STRONGER STORMS. STEADILY INCREASING MID LVL FLOW
WILL ALSO PROVIDE ENOUGH SHEAR FOR SOME STORM ORGANIZATION. THE
STRONGER CONVECTIVE ELEMENTS THU AFTERNOON WILL BE CAPABLE OF
GUSTY WINDS...BUT PWAT VALUES CLIMBING TOWARDS +2 SD ABOVE NORMAL
WILL KEEP HEAVY RNFL AS THE MORE WIDESPREAD THREAT.
ATTENTION THEN TURNS TO FRI AND SAT WHERE A SEASONABLY STRONG UPR
TROF WILL DIG ACROSS THE NRN TIER OF CONUS. THIS WILL DRIVE A
STRONG COLD FNT THRU THE REGION ON SAT. HOT AND HUMID AIR MASS IN
PLACE AHEAD OF THE FNT WILL PROVIDE AMPLE INSTABILITY. 16/00Z GFS
ENSEMBLES THEN INDICATE THAT H8 WIND FIELD WILL STRENGTHEN TO
AROUND 40 KT...NEARLY 2 SD ABOVE NORMAL FOR THIS TIME OF YEAR.
THIS ANOMALOUSLY STRONG FLOW WILL MEAN STORM ORGANIZATION IS
LIKELY...WITH DEEP UNIDIRECTIONAL FLOW FAVORING LINE SEGMENTS AND
CLUSTERS. THE STRONG FLOW ALOFT WILL SUPPORT A WIND DAMAGE
THREAT...AND CONTINUED HIGH PWATS WILL ALSO MEAN HEAVY RNFL. STORM
MOTION WILL BE FASTER THAN PAST WEEKS...BUT THE GRADUAL APPROACH
OF THE COLD FNT COULD MEAN SEVERAL ROUNDS OF TSTMS FOR SOME OF THE
SAME AREAS. REPEATED HEAVY PCPN EVENTS FOR THE NRN MTNS COULD MEAN
FLASH FLOOD REMAINS ELEVATED...DESPITE QUICKLY MOVING STORMS. THE
AREA REMAINS IN THE STORM PREDICTION CENTER/S DAY 4 TROUGH 8
SEVERE WEATHER OUTLOOK.
AFTER COLD FNT PUSHES THRU THE CWFA...COOLER AND MUCH DRIER AIR
WILL REPLACE THE STAGNANT AIR MASS OF THE LAST FEW WEEKS. EXPECT
HIGH TEMPS TO DROP BACK INTO THE 70S TO NEAR 80...WITH OVERNIGHT
LOW DIPPING INTO THE 50S AND CLOSER TO NORMAL.
&&
.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
SHORT TERM...VFR THIS MORNING EXCEPT FOR SOME PATCHY VALLEY FOG.
FOG WILL AGAIN APPEAR IN VALLEYS WEDNESDAY MORNING. ISOLATED MVFR
IN THUNDERSTORMS THIS AFTERNOON THEN MORE NUMEROUS ON WEDNESDAY.
LONG TERM...VFR CONDS EXPECTED TO PREVAIL THRU THE WEEKEND. LOCAL
MVFR/IFR CIGS AND VSBYS ARE POSSIBLE IN VALLEY FOG OVERNIGHT THRU
FRI. SCT SHRA/TSTMS WILL BE INCREASINGLY LIKELY EACH AFTERNOON
THRU SAT.
&&
.MARINE...
SHORT TERM...LIGHT WINDS AND CALM SEAS TODAY, THEN INCREASING
SOUTHERLY WINDS ON WEDNESDAY AFTERNOON SHOULD PUSH SEAS TO 3 TO 4
FEET.
LONG TERM...CONTINUED SWLY FLOW AHEAD OF APPROACHING COLD FNT WILL
BRING SEAS UP TO 5 FT OR HIGHER BY THE LATE WEEK AND EARLY
WEEKEND.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...STJEAN
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
935 AM EDT TUE JUL 16 2013
.SYNOPSIS...
HIGH PRESSURE WILL PROMOTE WARM AND HUMID CONDITIONS THIS WEEK.
THUNDERSTORM CHANCES WILL INCREASE WITH A SATURDAY COLD FRONT.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
ADJUSTMENTS TO HOURLY TRENDS WERE THE ONLY ADJUSTMENTS NEEDED FOR
THE MID MRNG UPDATE.
PREVIOUS...
THE HRRR AND THE LAMP SEEM TO BE HANDLING THE CURRENT TEMPERATURE
TRENDS QUITE WELL EARLY THIS MORNING...SO THEY WERE USED THROUGH
THE DAY TODAY. THIS BRINGS THE DEWPOINTS UP THROUGH THE AFTERNOON
WHICH IN TURN BRINGS APPARENT TEMPERATURES INTO THE MID TO UPPER
90S OVER MY EASTERN OH...SOUTHWESTERN PA...AND NORTHERN WV
PANHANDLE COUNTIES. THUS...AN SPS WILL BE ISSUED WITH THE MORNING
PACKAGE FOR HOT TEMPERATURES AS IT WILL BE JUST UNDER HEAT
ADVISORY CRITERIA.
THE MID LEVEL HIGH WILL CONTINUE TO SHIFT WESTWARD TODAY ALLOWING
FOR THE CAP TO WEAKEN THIS AFTERNOON. THIS COULD ALLOW FOR A BIT
MORE THUNDERSTORM COVERAGE THAN YESTERDAY...MAINLY ALONG THE LAKE
BREEZE BOUNDARY TO THE NORTH AND IN THE HIGHER ELEVATIONS.
HOWEVER...THE HI RES MODELS ARE SUGGESTING THAT A FEW
SHOWERS/THUNDERSTORMS COULD DEVELOP A BIT FURTHER SOUTH AND
WEST...SO A ISOLATED THUNDERSTORM MENTION WAS ADDED TO ALL OF THE
FORECAST AREA BY LATE AFTERNOON. CONFIDENCE IN THIS COVERAGE
REMAINS LOW HOWEVER...ESPECIALLY OVER EASTERN OHIO...SO FELT AN
ISOLATED MENTION WOULD SUFFICE.
HIGH PRES WILL CONTINUE TO SLOWLY MOVE WESTWARD THROUGH THE
PERIOD. CONTINUED A SLIGHT CHANCE MENTION FOR THUNDERSTORMS NORTH
AND ALONG THE RIDGES WEDNESDAY. APPARENT TEMPERATURES WILL ONCE
AGAIN GET VERY CLOSE TO 100 DEGREES WEDNESDAY AFTERNOON. FOR
NOW...WILL CONTINUE TO HIGHLIGHT HOT...HUMID WEATHER IN THE HWO.
BIAS CORRECTED MOS WAS USED FOR TEMPERATURES...WITH ABOVE SEASONAL
VALUES EXPECTED BOTH DAY AND NIGHT.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
VERY HUMID AMS WILL PERSIST THRU THE WK OWING TO STAGNANT FLOW
AMID FLATTENING H5 RDG. BY THU...MID-LVL FLOW WILL INCR SLGTLY AS
JET STREAM ACRS CANADA SINKS EQUATORWARD.
CAP STILL XPCD TO BE PRESENT ON THU...BUT SOMEWHAT WKR THAN PREV
DAYS OWING TO WWD DEPARTURE OF RDG. VERY MODEST CNVGNC ALONG
INVERTED SFC TROF AND TERRAIN CIRCULATIONS WILL PROVIDE ONLY CLR
FOCI FOR ANY CNVCTV DVLPMT THU AFTN. ISOLD-SCT CVRG OF TSTMS WERE
INCLUDED ON THU...SUBSIDING THU EVE WITH LOSS OF HEATING.
BELT OF MDT WSWLY H5 FLOW SPREADS SWD ON FRI AS AGGRESSIVE TROF
DIGS INTO S-CNTRL CANADA AND NRN PLNS. PRIMARY FOCUS FOR TSTM
DVLPMT WILL BE ALONG ASSOCIATED CDFNT MAINLY NW OF FCST AREA. BUT
GIVEN INCRG LIFT AND QUALITY INSOLATION...TSTMS CANNOT BE RULED
OUT ON FRI. MDT-STG INSTBY MAY COMPENSATE FOR MODEST SHEAR AND
COULD PROMOTE A THREAT OF SVR TSTMS WITH DMGG WIND GUSTS ON FRI
AFTN.
MAXIMA XPCD TO BE CAPPED IN THE LWR 90S OWING TO VERY HIGH MSTR
CONTENT OF BNDRY LYR. THE COMBINATION OF LWR 90S TEMPS AND DEWPT
TEMPS IN THE LWR-MID 70S WILL YIELD HEAT INDICES IN THE UPR 90S-NR
100 BOTH WED AND THU. HEAT CONCERNS WILL BE HIGHLIGHTED IN HWO.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
SGFNT SVR EPISODE RMNS PSBL ON SAT AS VERY HUMID AMS WILL RMN IN
THE RGN IN ADVC OF ARRIVING CDFNT. H5 FLOW WILL INCR FRI NGT-SAT
AS SHRTWV TROF CROSSES GRTLKS RGN. CNVCTN XPCD TO DVLP RELATIVELY
EARLY ON SAT ALONG AND AHD OF ADVCG CDFNT.
STG INSTBY AND MDT BULK SHEAR WILL SUPPORT ORGANIZED UPDRAFTS.
SHEAR VECTOR WILL BE RELATIVELY PARALLEL TO ADVCG CDFNT...SO
CNVCTN XPCD TO BCM LINEAR RELATIVELY QUICKLY. OWING TO VERY HIGH
FRZG LVLS AND STEEP LAPSE RATES...DMGG WIND GUSTS WILL BE PRIMARY
SVR THREAT FROM THESE TSTMS.
CDFNT CROSSES RGN BY SAT EVE AND SCOURS OUT MSTR. PCPN WILL SHIFT
SE OF FCST AREA BY SUN AFTN. TEMPS WILL TREND TWD LWR 80S EARLY
NEXT WK IN WAKE OF CDFNT PASSAGE.
NELY UPSLP FLOW ON MON MAY SUPPORT A FEW SHWRS ALONG TERRAIN.
GUIDANCE SUGGESTS A SHRTWV TROF WILL STRENGTHEN SWLY LOW-LVL FLOW
BY TUE AND WILL PROMOTE INCRG CHCS FOR TSTMS AS BNDRY-LYR MSTR
INCRS.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
GENERAL VFR EXPECTED AT ALL SITES TODAY. EXPECT DIURNAL CU TO
DEVELOP ONCE AGAIN...BUT BE MORE WIDESPREAD IN COVERAGE WITH
WESTWARD TRACKING HIGH. THIS COULD ALSO PROMOTE A BIT MORE
SHOWER/THUNDERSTORM DEVELOPMENT IN BOTH THE LAKE BREEZE AND ALONG
THE RIDGES. WITHOUT SOLID CONFIDENCE THAT ANY SITE WILL BE
IMPACTED...LEFT SHRA/TSRA MENTION OUT FOR NOW.
WINDS WILL REMAIN LIGHT AND VARIABLE.
.OUTLOOK.../TUESDAY NIGHT THROUGH SATURDAY/...
RESTRICTIONS IN MRNG FOG WILL BE PSBL EACH DAY. BEST CHC FOR MORE
WDSPRD RESTRICTIONS WILL BE SAT AS CDFNT PASSAGE INVIGORATES BROAD
CVRG OF TSTMS IN THE RGN.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
15
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
639 AM EDT TUE JUL 16 2013
.SYNOPSIS...
HOT AND HUMID CONDITIONS ARE EXPECTED THROUGH THE WEEK AS HIGH
PRESSURE DOMINATES THE WEATHER. THUNDERSTORM CHANCES WILL INCREASE
FRIDAY AND SATURDAY AS A COLD FRONT APPROACHES AND CROSSES THE
REGION.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
THE HRRR AND THE LAMP SEEM TO BE HANDLING THE CURRENT TEMPERATURE
TRENDS QUITE WELL EARLY THIS MORNING...SO THEY WERE USED THROUGH
THE DAY TODAY. THIS BRINGS THE DEWPOINTS UP THROUGH THE AFTERNOON
WHICH IN TURN BRINGS APPARENT TEMPERATURES INTO THE MID TO UPPER
90S OVER MY EASTERN OH...SOUTHWESTERN PA...AND NORTHERN WV
PANHANDLE COUNTIES. THUS...AN SPS WILL BE ISSUED WITH THE MORNING
PACKAGE FOR HOT TEMPERATURES AS IT WILL BE JUST UNDER HEAT
ADVISORY CRITERIA.
THE MID LEVEL HIGH WILL CONTINUE TO SHIFT WESTWARD TODAY ALLOWING
FOR THE CAP TO WEAKEN THIS AFTERNOON. THIS COULD ALLOW FOR A BIT
MORE THUNDERSTORM COVERAGE THAN YESTERDAY...MAINLY ALONG THE LAKE
BREEZE BOUNDARY TO THE NORTH AND IN THE HIGHER ELEVATIONS.
HOWEVER...THE HI RES MODELS ARE SUGGESTING THAT A FEW
SHOWERS/THUNDERSTORMS COULD DEVELOP A BIT FURTHER SOUTH AND
WEST...SO A ISOLATED THUNDERSTORM MENTION WAS ADDED TO ALL OF THE
FORECAST AREA BY LATE AFTERNOON. CONFIDENCE IN THIS COVERAGE
REMAINS LOW HOWEVER...ESPECIALLY OVER EASTERN OHIO...SO FELT AN
ISOLATED MENTION WOULD SUFFICE.
HIGH PRES WILL CONTINUE TO SLOWLY MOVE WESTWARD THROUGH THE
PERIOD. CONTINUED A SLIGHT CHANCE MENTION FOR THUNDERSTORMS NORTH
AND ALONG THE RIDGES WEDNESDAY. APPARENT TEMPERATURES WILL ONCE
AGAIN GET VERY CLOSE TO 100 DEGREES WEDNESDAY AFTERNOON. FOR
NOW...WILL CONTINUE TO HIGHLIGHT HOT...HUMID WEATHER IN THE HWO.
BIAS CORRECTED MOS WAS USED FOR TEMPERATURES...WITH ABOVE SEASONAL
VALUES EXPECTED BOTH DAY AND NIGHT.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
VERY HUMID AMS WILL PERSIST THRU THE WK OWING TO STAGNANT FLOW
AMID FLATTENING H5 RDG. BY THU...MID-LVL FLOW WILL INCR SLGTLY AS
JET STREAM ACRS CANADA SINKS EQUATORWARD.
CAP STILL XPCD TO BE PRESENT ON THU...BUT SOMEWHAT WKR THAN PREV
DAYS OWING TO WWD DEPARTURE OF RDG. VERY MODEST CNVGNC ALONG
INVERTED SFC TROF AND TERRAIN CIRCULATIONS WILL PROVIDE ONLY CLR
FOCI FOR ANY CNVCTV DVLPMT THU AFTN. ISOLD-SCT CVRG OF TSTMS WERE
INCLUDED ON THU...SUBSIDING THU EVE WITH LOSS OF HEATING.
BELT OF MDT WSWLY H5 FLOW SPREADS SWD ON FRI AS AGGRESSIVE TROF
DIGS INTO S-CNTRL CANADA AND NRN PLNS. PRIMARY FOCUS FOR TSTM
DVLPMT WILL BE ALONG ASSOCIATED CDFNT MAINLY NW OF FCST AREA. BUT
GIVEN INCRG LIFT AND QUALITY INSOLATION...TSTMS CANNOT BE RULED
OUT ON FRI. MDT-STG INSTBY MAY COMPENSATE FOR MODEST SHEAR AND
COULD PROMOTE A THREAT OF SVR TSTMS WITH DMGG WIND GUSTS ON FRI
AFTN.
MAXIMA XPCD TO BE CAPPED IN THE LWR 90S OWING TO VERY HIGH MSTR
CONTENT OF BNDRY LYR. THE COMBINATION OF LWR 90S TEMPS AND DEWPT
TEMPS IN THE LWR-MID 70S WILL YIELD HEAT INDICES IN THE UPR 90S-NR
100 BOTH WED AND THU. HEAT CONCERNS WILL BE HIGHLIGHTED IN HWO.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
SGFNT SVR EPISODE RMNS PSBL ON SAT AS VERY HUMID AMS WILL RMN IN
THE RGN IN ADVC OF ARRIVING CDFNT. H5 FLOW WILL INCR FRI NGT-SAT
AS SHRTWV TROF CROSSES GRTLKS RGN. CNVCTN XPCD TO DVLP RELATIVELY
EARLY ON SAT ALONG AND AHD OF ADVCG CDFNT.
STG INSTBY AND MDT BULK SHEAR WILL SUPPORT ORGANIZED UPDRAFTS.
SHEAR VECTOR WILL BE RELATIVELY PARALLEL TO ADVCG CDFNT...SO
CNVCTN XPCD TO BCM LINEAR RELATIVELY QUICKLY. OWING TO VERY HIGH
FRZG LVLS AND STEEP LAPSE RATES...DMGG WIND GUSTS WILL BE PRIMARY
SVR THREAT FROM THESE TSTMS.
CDFNT CROSSES RGN BY SAT EVE AND SCOURS OUT MSTR. PCPN WILL SHIFT
SE OF FCST AREA BY SUN AFTN. TEMPS WILL TREND TWD LWR 80S EARLY
NEXT WK IN WAKE OF CDFNT PASSAGE.
NELY UPSLP FLOW ON MON MAY SUPPORT A FEW SHWRS ALONG TERRAIN.
GUIDANCE SUGGESTS A SHRTWV TROF WILL STRENGTHEN SWLY LOW-LVL FLOW
BY TUE AND WILL PROMOTE INCRG CHCS FOR TSTMS AS BNDRY-LYR MSTR
INCRS.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
GENERAL VFR EXPECTED AT ALL SITES TODAY AFTER MORNING FOG BURNS
OFF. KFKL...KDUJ...KZZV...AND KHLG ARE CURRENTLY EXPERIENCING IFR
VISIBILITIES THAT SHOULD GRADUALLY IMPROVE TO VFR THIS MORNING.
EXPECT DIURNAL CU TO DEVELOP ONCE AGAIN...BUT BE MORE WIDESPREAD IN
COVERAGE WITH WESTWARD TRACKING HIGH. THIS COULD ALSO PROMOTE A
BIT MORE SHOWER/THUNDERSTORM DEVELOPMENT IN BOTH THE LAKE BREEZE
AND ALONG THE RIDGES. WITHOUT SOLID CONFIDENCE THAT ANY SITE WILL
BE IMPACTED...LEFT SHRA/TSRA MENTION OUT FOR NOW.
WINDS WILL REMAIN LIGHT AND VARIABLE.
.OUTLOOK.../TUESDAY NIGHT THROUGH SATURDAY/...
RESTRICTIONS IN MRNG FOG WILL BE PSBL EACH DAY. BEST CHC FOR MORE
WDSPRD RESTRICTIONS WILL BE SAT AS CDFNT PASSAGE INVIGORATES BROAD
CVRG OF TSTMS IN THE RGN.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
442 AM EDT TUE JUL 16 2013
.SYNOPSIS...
HOT AND HUMID CONDITIONS ARE EXPECTED THROUGH THE WEEK AS HIGH
PRESSURE DOMINATES THE WEATHER. THUNDERSTORM CHANCES WILL INCREASE
FRIDAY AND SATURDAY AS A COLD FRONT APPROACHES AND CROSSES THE
REGION.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
TEMPERATURES AND DEWPOINTS ACROSS THE FORECAST AREA ARE STRUGGLING
TO DROP EARLY THIS MORNING. THE HRRR AND THE LAMP SEEM TO BE
HANDLING THIS QUITE WELL...SO THEY WERE USED THROUGH THE DAY
TODAY. THIS BRINGS THE DEWPOINTS UP THROUGH THE AFTERNOON WHICH IN
TURN BRINGS APPARENT TEMPERATURES INTO THE MID TO UPPER 90S OVER
MY EASTERN OH...SOUTHWESTERN PA...AND NORTHERN WV PANHANDLE
COUNTIES. THUS...AN SPS WILL BE ISSUED WITH THE MORNING PACKAGE
FOR HOT TEMPERATURES AS IT WILL BE JUST UNDER HEAT ADVISORY
CRITERIA.
THE MID LEVEL HIGH WILL CONTINUE TO SHIFT WESTWARD TODAY ALLOWING
FOR THE CAP TO WEAKEN THIS AFTERNOON. THIS COULD ALLOW FOR A BIT
MORE THUNDERSTORM COVERAGE THAN YESTERDAY...MAINLY ALONG THE LAKE
BREEZE BOUNDARY TO THE NORTH AND IN THE HIGHER ELEVATIONS.
HOWEVER...THE HI RES MODELS ARE SUGGESTING THAT A FEW
SHOWERS/THUNDERSTORMS COULD DEVELOP A BIT FURTHER SOUTH AND
WEST...SO A ISOLATED THUNDERSTORM MENTION WAS ADDED TO ALL OF THE
FORECAST AREA BY LATE AFTERNOON. CONFIDENCE IN THIS COVERAGE
REMAINS LOW HOWEVER...ESPECIALLY OVER EASTERN OHIO...SO FELT AN
ISOLATED MENTION WOULD SUFFICE.
HIGH PRES WILL CONTINUE TO SLOWLY MOVE WESTWARD THROUGH THE
PERIOD. CONTINUED A SLIGHT CHANCE MENTION FOR THUNDERSTORMS NORTH
AND ALONG THE RIDGES WEDNESDAY. APPARENT TEMPERATURES WILL ONCE
AGAIN GET VERY CLOSE TO 100 DEGREES WEDNESDAY AFTERNOON. FOR
NOW...WILL CONTINUE TO HIGHLIGHT HOT...HUMID WEATHER IN THE HWO.
BIAS CORRECTED MOS WAS USED FOR TEMPERATURES...WITH ABOVE SEASONAL
VALUES EXPECTED BOTH DAY AND NIGHT.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
VERY HUMID AMS WILL PERSIST THRU THE WK OWING TO STAGNANT FLOW
AMID FLATTENING H5 RDG. BY THU...MID-LVL FLOW WILL INCR SLGTLY AS
JET STREAM ACRS CANADA SINKS EQUATORWARD.
CAP STILL XPCD TO BE PRESENT ON THU...BUT SOMEWHAT WKR THAN PREV
DAYS OWING TO WWD DEPARTURE OF RDG. VERY MODEST CNVGNC ALONG
INVERTED SFC TROF AND TERRAIN CIRCULATIONS WILL PROVIDE ONLY CLR
FOCI FOR ANY CNVCTV DVLPMT THU AFTN. ISOLD-SCT CVRG OF TSTMS WERE
INCLUDED ON THU...SUBSIDING THU EVE WITH LOSS OF HEATING.
BELT OF MDT WSWLY H5 FLOW SPREADS SWD ON FRI AS AGGRESSIVE TROF
DIGS INTO S-CNTRL CANADA AND NRN PLNS. PRIMARY FOCUS FOR TSTM
DVLPMT WILL BE ALONG ASSOCIATED CDFNT MAINLY NW OF FCST AREA. BUT
GIVEN INCRG LIFT AND QUALITY INSOLATION...TSTMS CANNOT BE RULED
OUT ON FRI. MDT-STG INSTBY MAY COMPENSATE FOR MODEST SHEAR AND
COULD PROMOTE A THREAT OF SVR TSTMS WITH DMGG WIND GUSTS ON FRI
AFTN.
MAXIMA XPCD TO BE CAPPED IN THE LWR 90S OWING TO VERY HIGH MSTR
CONTENT OF BNDRY LYR. THE COMBINATION OF LWR 90S TEMPS AND DEWPT
TEMPS IN THE LWR-MID 70S WILL YIELD HEAT INDICES IN THE UPR 90S-NR
100 BOTH WED AND THU. HEAT CONCERNS WILL BE HIGHLIGHTED IN HWO.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
SGFNT SVR EPISODE RMNS PSBL ON SAT AS VERY HUMID AMS WILL RMN IN
THE RGN IN ADVC OF ARRIVING CDFNT. H5 FLOW WILL INCR FRI NGT-SAT
AS SHRTWV TROF CROSSES GRTLKS RGN. CNVCTN XPCD TO DVLP RELATIVELY
EARLY ON SAT ALONG AND AHD OF ADVCG CDFNT.
STG INSTBY AND MDT BULK SHEAR WILL SUPPORT ORGANIZED UPDRAFTS.
SHEAR VECTOR WILL BE RELATIVELY PARALLEL TO ADVCG CDFNT...SO
CNVCTN XPCD TO BCM LINEAR RELATIVELY QUICKLY. OWING TO VERY HIGH
FRZG LVLS AND STEEP LAPSE RATES...DMGG WIND GUSTS WILL BE PRIMARY
SVR THREAT FROM THESE TSTMS.
CDFNT CROSSES RGN BY SAT EVE AND SCOURS OUT MSTR. PCPN WILL SHIFT
SE OF FCST AREA BY SUN AFTN. TEMPS WILL TREND TWD LWR 80S EARLY
NEXT WK IN WAKE OF CDFNT PASSAGE.
NELY UPSLP FLOW ON MON MAY SUPPORT A FEW SHWRS ALONG TERRAIN.
GUIDANCE SUGGESTS A SHRTWV TROF WILL STRENGTHEN SWLY LOW-LVL FLOW
BY TUE AND WILL PROMOTE INCRG CHCS FOR TSTMS AS BNDRY-LYR MSTR
INCRS.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
GENERAL VFR EXPECTED AT MOST TAF SITES OVERNIGHT. SHOWERS FROM LAST
EVE IN THE VICINITY OF KFKL AND KDUJ MAY PROVIDE ENOUGH LOW LEVEL
SATURATION FOR FOG TO DEVELOP...AS IS ALREADY THE CASE AT DUJ.
GENERALLY THINK THIS FOG WILL BE MVFR BUT THEY COULD OCCASIONALLY
DROP TO IFR. THINK THIS COULD ALSO BE THE CASE FOR ZZV...WITH
DEWPOINTS EXPECTED TO REMAIN ELEVATED THERE.
EXPECT DIURNAL CU TO DEVELOP ONCE AGAIN TUESDAY...BUT BE WIDER IN
COVERAGE WITH WESTWARD TRACKING HIGH. THIS COULD ALSO PROMOTE A BIT
MORE SHOWER/THUNDERSTORM DEVELOPMENT IN BOTH THE LAKE BREEZE AND
ALONG THE RIDGES. WITHOUT SOLID CONFIDENCE THAT ANY SITE WILL BE
IMPACTED...LEFT SHRA/TSRA MENTION OUT FOR NOW.
WINDS WILL REMAIN LIGHT AND VARIABLE.
.OUTLOOK.../TUESDAY NIGHT THROUGH SATURDAY/...
RESTRICTIONS IN MRNG FOG WILL BE PSBL EACH DAY. BEST CHC FOR MORE
WDSPRD RESTRICTIONS WILL BE SAT AS CDFNT PASSAGE INVIGORATES BROAD
CVRG OF TSTMS IN THE RGN.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
34/KRAMAR
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
332 AM EDT TUE JUL 16 2013
.SYNOPSIS...
HOT AND HUMID CONDITIONS ARE EXPECTED ALL WEEK WITH HIGH PRESSURE
OVERHEAD. A COLD FRONT DROPS SOUTH FROM CANADA INCREASING THE
CHANCE OF SHOWERS AND THUNDERSTORMS FRIDAY AND SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
TEMPERATURES AND DEWPOINTS ACROSS THE FORECAST AREA ARE STRUGGLING
TO DROP EARLY THIS MORNING. THE HRRR AND THE LAMP SEEM TO BE
HANDLING THIS QUITE WELL...SO THEY WERE USED THROUGH THE DAY
TODAY. THIS BRINGS THE DEWPOINTS UP THROUGH THE AFTERNOON WHICH IN
TURN BRINGS APPARENT TEMPERATURES INTO THE MID TO UPPER 90`S OVER
MY EASTERN OH...SOUTHWESTERN PA...AND NORTHERN WV PANHANDLE
COUNTIES. THUS...AN SPS WILL BE ISSUED WITH THE MORNING PACKAGE
FOR HOT TEMPERATURES AS IT WILL BE JUST UNDER HEAT ADVISORY
CRITERIA.
THE MID LEVEL HIGH WILL CONTINUE TO SHIFT WESTWARD TODAY ALLOWING
FOR THE CAP TO WEAKEN THIS AFTERNOON. THIS COULD ALLOW FOR A BIT
MORE THUNDERSTORM COVERAGE THAN YESTERDAY...MAINLY ALONG THE LAKE
BREEZE BOUNDARY TO THE NORTH AND IN THE HIGHER ELEVATIONS.
HOWEVER...THE HI RES MODELS ARE SUGGESTING THAT A FEW
SHOWERS/THUNDERSTORMS COULD DEVELOP A BIT FURTHER SOUTH AND
WEST...SO A ISOLATED THUNDERSTORM MENTION WAS ADDED TO ALL OF THE
FORECAST AREA BY LATE AFTERNOON. CONFIDENCE IN THIS COVERAGE
REMAINS LOW HOWEVER...ESPECIALLY OVER EASTERN OHIO...SO FELT AN
ISOLATED MENTION WOULD SUFFICE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
HIGH PRES WILL CONTINUE TO SLOWLY MOVE WESTWARD THROUGH THE
PERIOD. CONTINUED A SLIGHT CHANCE MENTION FOR THUNDERSTORMS NORTH
AND ALONG THE RIDGES WEDNESDAY. APPARENT TEMPERATURES WILL ONCE
AGAIN GET VERY CLOSE TO 100 DEGREES WEDNESDAY AFTERNOON. FOR
NOW...WILL CONTINUE TO HIGHLIGHT HOT...HUMID WEATHER IN THE HWO.
BIAS CORRECTED MOS WAS USED FOR TEMPERATURES...WITH ABOVE SEASONAL
VALUES EXPECTED BOTH DAY AND NIGHT.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
INCRSG FLOW ALOFT WITH SEWD PROPAGATING HUDSON BAY LOW WL SPPRT INCRSG
TSTM POTENTIAL AS THE ASSOCIATED SFC FRONT...AND WEEKEND APPCH.
WITH THAT INCRSD FLOW WL COME SEVERE POTENTIAL WHICH HAS BEEN
MENTIONED IN THE HAZARDOUS WEATHER OUTLOOK FOR NOW.
THE FRONT IS PROJECTED ACROSS THE AREA BY SUNDAY WITH WANING PCPN
CHCS AND A COOLER/DRIER AIRMASS.
&&
.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
GENERAL VFR EXPECTED AT MOST TAF SITES OVERNIGHT. SHOWERS FROM LAST
EVE IN THE VICINITY OF KFKL AND KDUJ MAY PROVIDE FOR ENOUGH LOW
LEVEL SATURATION FOR FOG TO DEVELOP...AS IS ALREADY THE CASE AT DUJ.
GENERALLY THINK THIS FOG WILL BE MVFR BUT THEY COULD OCCASIONALLY
DROP TO IFR. THINK THIS COULD ALSO BE THE CASE FOR ZZV...WITH
DEWPOINTS EXPECTED TO REMAIN ELEVATED THERE.
EXPECT DIURNAL CU TO DEVELOP ONCE AGAIN TUESDAY...BUT BE WIDER IN
COVERAGE WITH WESTWARD TRACKING HIGH. THIS COULD ALSO PROMOTE A BIT
MORE SHOWER/THUNDERSTORM DEVELOPMENT IN BOTH THE LAKE BREEZE AND
ALONG THE RIDGES. WITHOUT SOLID CONFIDENCE THAT ANY SITE WILL BE
IMPACTED...LEFT SHRA/TSRA MENTION OUT FOR NOW.
WINDS WILL REMAIN LIGHT AND VARIABLE.
.OUTLOOK.../TUESDAY NIGHT THROUGH SATURDAY/...
RESTRICTIONS ARE POSSIBLE EACH MORNING WITH FOG. OTHERWISE...THE
BEST CHANCE FOR WIDESPREAD RESTRICTIONS WILL COME WITH INCREASED
PRECIPITATION CHANCES ON SATURDAY AS A COLD FRONT APPROACHES.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1041 PM EDT WED JUL 17 2013
.UPDATE...
ISSUED AT 1038 PM EDT WED JUL 17 2013
THE FRONTAL BOUNDARY IS BASICALLY RIGHT OVER THE AREA. SCATTERED
SHOWERS AND THUNDERSTORMS DEVELOPED THIS AFTERNOON HELPED BY THE
UNSTABLE AIRMASS AND LAKE BREEZE BOUNDARIES. NOW...SHOWERS AND
THUNDERSTORMS HAVE ONCE AGAIN DEVELOPED AND FOCUSED MORE ON THE MAIN
FRONTAL BOUNDARY. THIS ACTIVITY EXTENDS FROM UPPER MICHIGAN WEST
INTO NRN MN. THE MAIN CONCERN IN THE UPDATE IS THE EVOLUTION OF
CONVECTION OVERNIGHT. SOME OF THE RAPID UPDATE MODELS INCLUDING THE
LOCAL RUNS OF THE WRF BASED ON THE RAP...SUGGEST THAT AS THE 850MB
FLOW BACKS TONIGHT AND STRENGTHENS OVER MN...AN MCS TYPE FEATURE
WILL DEVELOP AND TRACK ALONG THE 850MB THERMAL GRADIENT.
MEANWHILE...THE NAM AND THE HRRR SUGGEST THAT MULTICELL ACTIVITY
WILL CONTINUE ALONG THE FRONT AND TRACK OVER UPPER MICHIGAN
TONIGHT...ESPECIALLY LATE AS THE LOW LEVEL JET NOSES INTO THE AREA.
LOOKING AT THE LATEST RADAR TRENDS AND LACK OF ANY SIGNIFICANT
CONVECTIVE CLOUD DEVELOPMENT SOUTH OF THE FRONT...TEND TO BELIEVE
THE SCENARIO OF MORE MULTICELL DEVELOPMENT WITH SCATTERED-NUMEROUS
SHOWERS AND STORMS CONTINUING ALL NIGHT ESPECIALLY ACROSS THE WEST
HALF NEAR THE FRONTAL BOUNDARY. MOST LIKELY THE MAIN CONCERN TONIGHT
WILL BE THE HEAVY RAINFALL GIVEN THE HIGH FREEZING LEVELS ABOVE
15KFT AND PRECIPITABLE WATER VALUES ABOVE 2 INCHES...ALTHOUGH IF
SOME ORGANIZATION OF CONVECTION CAN OCCUR...UNIDIRECTIONAL EFFECTIVE
SHEAR VALUES OF 30-40KT WOULD SUGGEST A POTENTIAL WIND THREAT IF A
COLD POOL COULD DEVELOP.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 432 PM EDT WED JUL 17 2013
SFC OBS SHOW THAT AFTERNOON INLAND TEMPS HAVE REACHED THE CONVECTIVE
TEMPERATURE AT MANY LOCATIONS (INTO THE UPPER 80S AND LOWER 90S) AND
THUS HAVE STARTED TO SEE ISOLD SHRA/TSRA BEGINNING TO FORM OVER FAR
WRN UPR MI AND ALONG THE LAKE SUPERIOR LAKE BREEZE AND VNCTY OF
STALLED OUT FRONT IN NORTH CENTRAL UPR MI. WITH SBCAPE VALUES OF
2000-2500 J/KG AND ALONG WITH EFFECTIVE BULK SHEAR VALUES 35-40 KT
THERE IS A CHANCE THAT SOME OF THESE STORMS COULD BECOME SVR THIS
AFTERNOON INTO THIS EVENING. AS A RESULT SPC HAS MUCH OF UPR MI IN A
SLIGHT RISK FOR DAY1 CONVECTIVE OUTLOOK AND HAS JUST ISSUED A SWOMCD
FOR POSSIBLE SVR TSTM WATCH ISSUANCE. UNIDIRECTIONAL FLOW PARALLEL
TO THE SURFACE BOUNDARIES COULD SUPPORT STORM DEVELOPMENT FAVORING
FORWARD PROPAGATING LINE SEGMENTS AND SMALL BOW ECHOES WITH THE
POTENTIAL FOR DAMAGING WINDS AND HAIL ALONG WITH HEAVY RAIN.
EXPECT MUCH OF THE CONVECTION FORMING NOW TO GRADUALLY DIMINISH BY
LATE THIS EVENING AS HEATING/INSTABILITY WANES A BIT. STORMS SHOULD
THEN REDEVELOP LATER TONIGHT TO THE WEST OVER NRN MN AS WARM
ADVECTION KICKS IN ALONG STALLED OUT FRONTAL BOUNDARY IN RESPONSE TO
SHORTWAVE ROUNDING BROAD 5H RIDGE. LOOK FOR STORMS TO THEN TRACK ESE
ALONG FRONTAL BOUNDARY AND 850-300 MB THCKNS LINES AND INTO UPPER MI
ON THURSDAY...ESPECIALLY AFFECTING THE NRN AND ERN PORTIONS OF THE
CWA. WITH PWATS EXCEEDING 2.00 INCHES OR 190-195 PCT OF NORMAL...
TORRENTIAL HEAVY RAIN WILL BE POSSIBLE WITH STORMS AND THERE IS A
POTENTIAL FOR SOME FLASH FLOODING IF STORMS CONTINUE TO TRACK OVER
THE NRN AND ERN PORTIONS OF THE CWA DURING THE DAY ON THURSDAY. WITH
MLCAPES VALUES FORECAST TO BE NEAR 1500 J/KG AND DEEP LAYER SHEAR
VALUES OF 35-45 KT THERE IS AGAIN A POTENTIAL FOR SVR STORMS ON THU
AND SPC HAS ALL OF UPR MI HIGHLIGHTED IN SLIGHT RISK. COMBINATION OF
VEERING WIND PROFILE IN THE LOWER LVLS...STRONG
INSTABILITY...MODERATE TO STRONG DEEP LAYER...AND VERY MOIST
DEWPOINTS IN THE LOWER 70S CONTRIBUTING TO LOW LFC HEIGHTS COULD ALL
SUPPORT SUPERCELL DEVELOPMENT. ALTHOUGH THE PRIMARY THREATS WITH
THURSDAYS STORMS WILL LIKELY BE DAMAGING WIND...HEAVY RAIN AND LARGE
HAIL...ISOLD TORNADOES WILL ALSO BE POSSIBLE ESPECIALLY WITH ANY
STORMS THAT INTENSIFY AND MOVE EWD ALONG WARM/QUASISTATIONARY
FRONTAL BOUNDARY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 432 PM EDT WED JUL 17 2013
THURSDAY NIGHT THROUGH FRIDAY...A SLOW MOVING WARM FRONT WILL
CONTINUE TO LIFT FROM LAKE SUPERIOR NORTHWARD INTO ONTARIO DURING
THE EVENING HOURS AS A COLD FRONT IS PUSHED SOUTHEASTWARD OUT OF
SOUTHERN MANITOBA INTO NORTHEASTERN MN DURING THE OVERNIGHT HOURS. AT
THE SAME TIME THE UPPER LEVEL 500MB TROUGH WILL BEGIN DIGGING
SOUTHWARD INTO THE REGION. OUT AHEAD OF THE COLD FRONT A 40KT LLJ IS
EXPECTED TO DEVELOP AND REMAIN IN PLACE THROUGH THE OVERNIGHT HOURS.
THIS WILL CONTINUE TO PUMP MOISTURE INTO THE AREA. WHILE THE FORECAST
SOUNDINGS GAIN A BIT MORE MOISTURE THROUGHOUT...DRY AIR REMAINS IN
PORTIONS OF THE MID AND LOWER LEVELS...IF THIS IS NOT ALTERED BY
EARLIER CONVECTION...THEREFORE A CONTINUED WIND THREAT WILL EXIST
DURING THE EVENING AND OVERNIGHT HOURS. STRONG TO SEVERE
THUNDERSTORMS WILL BE POSSIBLE THURSDAY EVENING INTO THE OVERNIGHT
HOURS AS 0-6KM SHEAR VALUES ARE EXPECTED TO BE AROUND 40 TO 45 KNOTS
ALONG AND AHEAD OF THE COLD FRONT...WITH SHEAR VECTORS BECOMING
PERPENDICULAR TO THE FORCING. PWATS DURING THIS TIME PERIOD WILL BE
150-200 PERCENT OF NORMAL LEADING TO VERY HEAVY RAIN POTENTIAL. LATE
THURSDAY NIGHT THROUGH FRIDAY AFTERNOON THE COLD FRONT TO THE
NORTHWEST OF THE AREA WILL CONTINUE SOUTHEASTWARD PUSHING SOUTHEAST
OF THE AREA BY LATE FRIDAY AFTERNOON. FORCING ALONG AND AHEAD OF THE
COLD FRONT...ALONG WITH CONTINUED MOISTURE FLOWING INTO THE
SYSTEM...WILL KEEP AN INCREASED CHANCE FOR SHOWERS AND THUNDERSTORMS
IN THE FORECAST THROUGH FRIDAY MORNING. THE SEVERE THREAT WILL SHIFT
SOUTHEASTWARD INTO THE LOWER GREAT LAKES BY FRIDAY AFTERNOON AS THE
FRONT SHIFTS OUT OF THE AREA. THE UPPER LEVEL 500MB TROUGH WILL MOVE
DIRECTLY OVERHEAD BY FRIDAY AFTERNOON...WHICH WILL KEEP A CONTINUED
SLIGHT CHANCE OF SHOWERS AND POSSIBLY AN ISOLATED THUNDERSTORM IN THE
FORECAST...HOWEVER THE COVERAGE WILL BE GREATLY REDUCED.
FRIDAY NIGHT THROUGH SUNDAY NIGHT...FRIDAY NIGHT THE UPPER LEVEL
500MB TROUGH AXIS WILL SHIFT TO THE EAST OF THE UPPER GREAT LAKES AS
HIGH PRESSURE OVER SOUTHERN CANADA AND THE NORTHERN PLAINS BEGINS TO
BUILD INTO THE REGION. NORTHERLY FLOW ON THE EAST SIDE OF THE HIGH
WILL PUSH COOLER AND DRIER AIR IN FROM CANADA AS SHOWN BY OVERLAYING
1000-500MB RH...MSLP AND MOISTURE TRANSPORT. THE HIGH PRESSURE
SYSTEM WILL CONTINUE TO SHIFT EASTWARD BECOMING DIRECTLY OVERHEAD
SATURDAY NIGHT INTO THE DAY SUNDAY. WITH THE HIGH DIRECTLY
OVERHEAD...WINDS WILL BE LIGHT AND VARIABLE ALLOWING TEMPERATURES TO
POSSIBLY COOL INTO THE LOW AND MID 40S...ESPECIALLY OVER THE INLAND
WEST AREA. THE HIGH PRESSURE SYSTEM IS PROGGED TO REMAIN OVER THE
CWA INTO SUNDAY NIGHT.
MONDAY THROUGH WEDNESDAY...CONSIDERABLE DIFFERENCES REMAIN IN TIMING
AND STRENGTH OF UPPER LEVEL WAVES MOVING INTO THE AREA ALONG WITH
MOISTURE AND SURFACE PRESSURE FIELDS. THIS DIFFERENCE OCCURS FROM
MODEL TO MODEL AND FROM MODEL RUN TO MODEL RUN FOR THE WEATHER
PATTERN OVER THE FIRST HALF OF NEXT WEEK. WITH SUCH INCONSISTENCIES
HAVE DECIDED TO STICK WITH A CONSENSUS OF THE MODELS FOR THIS TIME
PERIOD.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 759 PM EDT WED JUL 17 2013
WILL CONTINUE WITH GENERAL VFR CONDITIONS THROUGH THE PERIOD.
SCATTEREDSHOWERS/THUNDERSTORMS CONTINUE ACROSS UPPER
MICHIGAN...HOWEVER THEY ARE FOCUSING ALONG THE LAKE BREEZE BOUNDARY
THAT HAS SEEMED TO MOVE SOUTH OF THE TERMINALS. COULD NOT RULE OUT A
SHOWER/STORM AT IWD AND SAW FOR THE NEXT HOUR OR TWO UNTIL THEY
DISSIPATE AFTER SUNSET. ADDITIONAL SHOWERS DEVELOPING OVER MN WILL
MOVE INTO UPPER MICHIGAN LATER TONIGHT AHEAD OF A WARM FRONT. TIMING
IS TRICKY...BUT THE BEST CHANCE FOR STORMS AT IWD WOULD BE AFTER
08Z..AND AT CMX AND SAW AFTER SUNRISE. ADDTIONAL STORMS MAY FIRE
LATE THU AFTN...AND THESE COULD END UP BEING STRONG AS THE COLD
FRONT APPROCHES.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 432 PM EDT WED JUL 17 2013
WITH RELATIVELY WEAK PRES GRADIENT AND HI STABILITY OVER THE
RELATIVELY COOL LAKE WATERS...EXPECT WINDS NO HIGHER THAN 20 KTS
THIS FORECAST PERIOD. THE MAIN WEATHER CONCERN WILL BE FOG WITH A
HUMID AIRMASS DOMINATING. THIS FOG IS LIKELY TO BE MOST WIDESPREAD
ON THU NIGHT FOLLOWING SOME STRONG TO POSSIBLY SVR THUNDERSTORMS
THAT WILL FURTHER SATURATE THE MARINE LAYER. THE ARRIVAL OF DRIER
AIR ON FRI SHOULD DISSIPATE THE FOG.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...MRD
SHORT TERM...VOSS
LONG TERM...KEC
AVIATION...MRD
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
353 PM EDT TUE JUL 16 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 345 PM EDT TUE JUL 16 2013
UPPER AIR PATTERN CONSISTS OF A STRONG 500 MB RIDGE OVER THE LOWER
GREAT LAKES WITH A TROUGH OVER SOUTH CENTRAL CANADA WITH CLOSED LOWS
OFF THE CA COAST AND ONE OVER ERN NM. THE 500 MB RIDGE REMAINS
STATIONARY TODAY WITH THE TROUGH CONTINUING TO MOVE EAST ACROSS
CENTRAL CANADA. THIS TROUGH HELPS TO START PUSHING DOWN THE RIDGE
THIS FORECAST PERIOD WITH THE WESTERLIES ALONG THE CANADIAN/U.S.
BORDER MOVING SLOWLY SOUTH WITH A COLD FRONT MOVING SLOWLY SOUTH AS
WELL.
SPOTTY CONVECTION THAT HAS BEEN KICKED OFF THIS AFTERNOON WAS CAUSED
BY REACHING CONVECTIVE TEMPERATURE WHICH WAS IN THE UPPER 80S. 12Z
GRB SOUNDING HAD A CONVECTIVE TEMPERATURE OF 87 AND THIS SEEMS TO BE
WHAT TEMPERATURES HAVE TO GET TO TO KICK OFF CONVECTION. RUC IS ALSO
SHOWING A 500 MB SPEED MAX JUST TO THE NORTH OF THE AREA AND WITH
MOISTURE ADVECTION...THIS ALSO HELPED TO KICK OFF THE CONVECTION
THIS AFTERNOON. LOOK FOR THIS TO CONTINUE INTO THE EVENING BEFORE
INSTABILITY DIMINISHES WITH LOSS OF HEATING TO STOP THE
THUNDERSTORMS FROM CONTINUING TO DEVELOP. STUFF HAS BEEN FAIRLY
SHORT LIVED AND EXPECT THAT TREND TO CONTINUE THIS AFTERNOON INTO
THIS EVENING.
BUMPED UP SOME LOW TEMPERATURES TONIGHT WITH A SOUTHWEST WIND
ALLOWING DOWNSLOPE TO CONTINUE AND A FEW SW AFFECTED DOWNSLOPE AREAS
COULD HAVE LOWS IN THE MID 70S TONIGHT WHICH IS VERY WARM.
OTHERWISE...DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST FOR
TEMPERATURES FOR HIGHS ON WED. AGREE WITH SPC OUTLOOK FOR SLIGHT
RISK OF SEVERE THUNDERSTORMS TOMORROW WITH UNIDIRECTIONAL WINDS AND
POOLING OF MOISTURE NEAR THE FRONT TO ALLOW STORMS WITH HIGH WINDS
TO DEVELOP WHICH WOULD BE THE MAIN THREAT FOR SEVERE WEATHER. FRONT
STARTS TO SAG DOWN INTO THE AREA AS WELL SO A FOCUSING MECHANISM FOR
CONVECTION IS THERE.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 345 PM EDT TUE JUL 16 2013
WEDNESDAY NIGHT...THE VERY SLOW MOVING COLD FRONT STRETCHING FROM
NORTH DAKOTA EASTWARD INTO SOUTHWESTERN QUEBEC WILL BECOME
STATIONARY OVERNIGHT WEDNESDAY NIGHT. AT THE SAME TIME HEIGHT FALLS
ASSOCIATED WITH THE UPPER LEVEL 500MB LOW OVER JAMES BAY WILL BEGIN
TO SINK SLOWLY SOUTHWARD AS IT SLOWLY WEAKENS THE HIGH PRESSURE
RIDGE THAT REMAINS OVER MUCH OF THE SOUTHEASTERN U.S. WITH THE FRONT
STRETCHING ACROSS MUCH OF LAKE SUPERIOR INTO THE NORTHERN PORTIONS
OF THE U.P. EXPECT THAT FORCING WILL BE GREAT ENOUGH TO ENHANCE THE
CHANCES FOR SHOWERS AND THUNDERSTORMS ACROSS MUCH OF THE AREA.
CONVERGENCE ASSOCIATED WITH A 25 TO 30 KNOT 850MB LLJ OVER CENTRAL
MN INTO NORTHERN WI WILL KEEP SHOWERS AND THUNDERSTORMS IN THE
FORECAST THROUGH THE OVERNIGHT HOURS...EVEN WITH THE LOSS OF DAYTIME
HEATING. DURING THE OVERNIGHT HOURS...THE CWA WILL ALSO BE UNDER
THE INFLUENCE OF THE RIGHT ENTRANCE REGION OF AN UPPER LEVEL 300MB
JET MAX...HELPING TO INCREASE FORCING FOR ASCENT. MU CAPE VALUES
OVERNIGHT ARE STILL EXPECTED TO BE AROUND 1000-1500 J/KG WITH DEEP
LAYER SHEAR VALUES ON THE ORDER OF 30 TO 35 KNOTS ACROSS THE AREA.
THE SHEAR IS UNIDIRECTIONAL...WHICH WOULD ALSO FAVOR MORE OF A WIND
THREAT. IT WOULD DEFINITELY NOT BE OUT OF THE QUESTION FOR SOME OF
THE STORMS TO BE FAIRLY STRONG OR EVEN SEVERE. THE MAIN THREAT FROM
THESE STORMS WOULD BE STRONG GUSTY WINDS AS DRY AIR REMAINS IN THE
MID LEVELS ALONG WITH AN INVERTED V TYPE SOUNDING IN THE LOW LEVELS
THROUGH THE OVERNIGHT HOURS...HELPING TO INCREASE COLD POOL
DEVELOPMENT. IT SHOULD BE KEPT IN MIND THAT MUCH OF THIS DEPENDS ON
CONVECTIVE DEVELOPMENT/TRACK THROUGH THE DAYTIME HOURS WEDNESDAY.
THURSDAY THROUGH FRIDAY...THE STATIONARY FRONT POSITIONED OVER LAKE
SUPERIOR THURSDAY MORNING IS PROGGED BY THE GFS/EC/GEM TO BEGIN
LIFTING NORTHWARD AS A WARM FRONT DURING THE AFTERNOON HOURS
THURSDAY. THIS FRONT WILL CONTINUE TO LIFT NORTHWARD INTO ONTARIO
DURING THE EVENING HOURS AS A COLD FRONT IS PUSHED SOUTHEASTWARD OUT
OF SOUTHERN MANITOBA INTO NORTHEASTERN MN DURING THE OVERNIGHT
HOURS AS THE UPPER LEVEL TROUGH BEGINS TO DIG INTO THE REGION. WITH
THE FRONT LIFTING NORTHWARD DURING THE DAY THURSDAY...IT WOULD NOT
BE OUT OF THE QUESTION TO SEE THE CLOUDS BREAK UP OVER THE
AREA...WHICH WILL HELP TO INCREASE THE CHANCES FOR SEVERE WEATHER
ACROSS THE CWA AS INSTABILITY INCREASES TO AROUND 1500-2500 J/KG.
DEEP LAYER SHEAR VALUES THROUGH THE DAY THURSDAY ARE PROGGED TO BE
AROUND 35 TO 40 KNOTS WHICH WOULD BE FAVORABLE FOR SEVERE WEATHER
DEVELOPMENT. THURSDAY AND THURSDAY EVENING WIND PROFILES INDICATED
THAT BOTH SPEED AND DIRECTIONAL SHEAR ARE AVAILABLE WHICH WOULD
SUPPORT A MORE ORGANIZED SEVERE EVENT. WHILE THE SOUNDING GAINS A
BIT MORE MOISTURE THROUGHOUT...DRY AIR REMAINS IN PORTIONS OF THE
LOWER LEVELS ALLOWING FOR AN INCREASED SEVERE WIND THREAT THROUGH
THE DAY THURSDAY INTO THE EVENING HOURS. A GREAT DEAL OF THE SEVERE
THREAT DURING THE DAY THURSDAY IS DEPENDENT UPON CLOUD COVER.
OVERNIGHT THURSDAY THROUGH FRIDAY MORNING THE COLD FRONT TO THE
NORTHWEST OF THE AREA WILL CONTINUE SOUTHEASTWARD PUSHING SOUTHEAST
OF THE AREA BY LATE FRIDAY AFTERNOON. AHEAD OF THE COLD FRONT
SHOWERS AND THUNDERSTORMS WILL CONTINUE TO BE LIKELY. STRONG TO
SEVERE THUNDERSTORMS WILL BE POSSIBLE THROUGH EARLY FRIDAY MORNING
AS 0-6KM SHEAR VALUES ARE EXPECTED TO BE AROUND 40 TO 45 KNOTS ALONG
AND AHEAD OF THE FRONT...WITH SHEAR VECTORS BECOMING PERPENDICULAR
TO THE FORCING. THE SEVERE THREAT WILL SHIFT SOUTHEASTWARD INTO THE
LOWER GREAT LAKES BY FRIDAY AFTERNOON AS THE FRONT SHIFTS OUT OF THE
AREA. WITH THAT BEING SAID A FEW SHOWERS MAY LINGER INTO THE
AFTERNOON HOURS AS THE UPPER LEVEL 500MB THROUGH MOVES DIRECTLY
OVERHEAD.
FRIDAY NIGHT THROUGH SUNDAY NIGHT...FRIDAY NIGHT THE UPPER LEVEL
500MB TROUGH AXIS LINGERS OVER THE UPPER GREAT LAKES ALONG WITH
REMNANT MOISTURE. THIS WILL KEEP THE CHANCE OF ISOLATED SHOWERS IN
THE FORECAST THROUGH FRIDAY NIGHT. SATURDAY...HIGH PRESSURE BUILDING
OVER SOUTHERN CANADA INTO THE NORTHERN PLAINS WILL BEGIN BUILDING
EASTWARD INTO THE GREAT LAKES REGION. AS THIS HAPPENS FLOW AROUND
THE EASTERN SIDE OF THE HIGH WILL ALLOW DRY AIR FROM CANADA TO SPILL
SOUTHWARD HELPING TO CLEAR THE SKIES FOR THE WEEKEND AND DRY THINGS
OUT A BIT. THIS HIGH IS PROGGED TO REMAIN IN THE AREA THROUGH
SUNDAY NIGHT.
MONDAY THROUGH TUESDAY...DIFFERENCES REMAIN IN MODEL SOLUTIONS TO
THE WEATHER PATTERN FOR THE FIRST HALF OF NEXT WEEK. THE GFS KEEPS
ZONAL TO SLIGHTLY RIDGED FLOW AT 500MB ACROSS THE AREA THROUGH THIS
TIME PERIOD WHILE THE EC BRINGS AND UPPER LEVEL TROUGH INTO THE
REGION. AT THE SAME TIME THE GFS PLACES A SURFACE HIGH OVER THE AREA
WHILE THE EC BUILDS A SURFACE LOW INTO THE REGION OUT OF SOUTHERN
CANADA. WITH THIS CONTINUED DISCONTINUITY...WILL STICK WITH A
CONSENSUS OF THE MODELS DURING THIS TIME PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 110 PM EDT TUE JUL 16 2013
VFR CONDITIONS WILL CONTINUE THROUGH THE PERIOD AT ALL SITES. ISOLD
SHRA/TS WL THEN POP UP WITH AFTERNOON HEATING AND PSBLY IMPACT SAW
BEFORE THE ARRIVAL OF DRYING ALF TENDS TO DIMINISH THIS ACTIVITY
LATE IN THE AFTN AND HAVE VCSH TO COVER THIS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 345 PM EDT TUE JUL 16 2013
FOG WILL CONTINUE TO BE PATCHY THROUGH WED MORNING ON LAKE SUPERIOR
AS COLD WATER WITH WARM AND HUMID AIR MOVING OVER THE TOP CAUSES FOG
TO FORM. AS THE FRONT STARTS TO COME DOWN ON WED...THIS SHOULD
DISRUPT THE FOG. A LOW PRESSURE SYSTEM AND FRONTAL BOUNDARY WILL
EFFECT THE REGION WEDNESDAY THROUGH FRIDAY...HOWEVER...WINDS SHOULD
REMAIN LIGHT AND GENERALLY LESS THAN 15 KNOTS. HIGH PRESSURE BUILDS
IN FOR MUCH OF THE WEEKEND ALLOWING WINDS TO REMAIN LIGHT AND
VARIABLE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...07
LONG TERM...KEC
AVIATION...07
MARINE...07
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
111 PM EDT TUE JUL 16 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 419 AM EDT TUE JUL 16 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SPRAWLING UPR RDG
CENTERED OVER THE LOWER GRT LKS. ALTHOUGH THE 00Z GRB RAOB INDICATES
THE TROPOSPHERE OVER THE UPR GRT LKS HAS MOISTENED CONSIDERABLY OVER
THE LAST DAY OR SO WITH 00Z PWAT UP TO 1.82 INCHES /185 PERCENT OF
NORMAL/...MID LVL WARMTH WITH H5 TEMPS ARND -5C HAS MAINTAINED
RATHER UNIMPRESSIVE MID LVL LAPSE RATES IN THE ABSENCE OF ANY
DYNAMIC FORCING UNDER THE RDG. THE CONVECTIVE TEMP ON THE 00Z GRB
SDNG WAS 94. A FEW -SHRA DID POP UP OVER WI YDAY AFTN...BUT THESE
DISSIPATED LAST EVNG WITH THE LOSS OF DAYTIME HEATING. HOWEVER...
MORE ISOLD -SHRA HAVE DVLPD OVER NW WI/ADJOINING MN IN AREA WHERE
RUC ANALYSIS SHOWS KINX NEAR 36. PERSISTENT BAND OF MSTR THAT HAS
PLAGUED NE MN/NW LK SUP WITH CLDS/SOME SHRA THE LAST FEW DAYS HAS
DRIFTED TO THE N INTO ONTARIO. OTRW...SFC TEMPS ARE RUNNING WELL ABV
NORMAL EARLY THIS MRNG DESPITE CLR-PCLDY SKIES. TO THE NW...THERE IS
A STRONGER SHRTWV JUST W OF LK WINNIPEG MOVING ENEWD THRU SRN CANADA.
MAIN FCST CONCERNS IN THE SHORT TERM ARE TEMPS AND SHRA/TS CHCS AS
UPR RDG REMAINS DOMINANT OVER THE GRT LKS.
TODAY...CENTER OF UPR RDG/SFC HI PRES OVER THE LOWER GRT LKS IS FCST
TO DRIFT ONLY SLOWLY TO THE W...SO MID LVL WARM AIR WL REMAIN OVER
THE CWA. STRONGER SHRTWV/ACCOMPANYING DYNAMICS LIFTING ENEWD THRU
SCENTRL CANADA WL RIDE WELL TO THE N OF UPR MI AND NOT IMPACT THE
CWA. BUT WITH DAYTIME HEATING...BULK OF NUMERICAL MODELS GENERATE
SHRA/TS OVER UPR MI TODAY. THERE ARE A NUMBER OF NEGATIVES FOR
PCPN...THE ABSENCE OF ANY DYNAMIC FORCING...FCST ACYC H85 SW FLOW
THAT WL RESULT IN ONLY WEAK LK BREEZE DVLPMENT OFF LK SUP...AND VERY
HI CONVECTIVE TEMP SHOWN ON THE 00Z GRB RAOB. HOWEVER...WITH SOME
ISOLD -SHRA OVER NW WI...SUSPECT SOME SHRA/TS WL IMPACT UPR MI
MAINLY BY LATE MRNG AFTER ONSET OF DAYTIME HEATING. FCST DRYING IN
THE AFTN IN THE WAKE OF AREA OF HIER KINX NOW MOVING TOWARD THE CWA
MAY CAUSE THE SHRA TO DIMINISH DESPITE MOVING TOWARD PEAK HEATING
TIME. THE BEST CHC FOR MORE PERSISTENT SHRA/TS WL BE OVER THE
ECENTRL CWA ON THE EDGE OF THE LK BREEZE BNDRY MOVING ONSHORE FM LK
MI. WITH FCST H85 TEMPS ARND 19C...EXPECT ANOTHER WARM DAY WITH MAX
TEMPS WELL INTO THE 80S TO LO 90S OVER THE INTERIOR. HIER HUMIDITY
WL MAKE THE AIR FEEL QUITE UNCOMFORTABLE...WITH APPARENT TEMPS
RISING TO ARND 95 AT SOME PLACES.
TNGT...COLD FNT ATTENDANT TO DISTURBANCE MOVING THRU CANADA AND INTO
HUDSON BAY IS PROGGED TO DRIFT S INTO NRN LK SUP BY 12Z WED UNDER
MODEST H5 HGT FALLS. CURRENT FCST SHOWS OVERNGT POPS OVER NRN LK SUP
CLOSE TO THIS INCOMING BNDRY AND AREA OF HIER FCST MID LVL RH...SO
WL RESTRICT FCST POPS TO THIS AREA AND KEEP THE REST OF THE CWA DRY
CLOSER TO HI PRES/CORE OF WARMER MID LVL AIR. WITH FCST H925 WINDS
UP TO 25-30 KTS UNDER SHARPENING PRES GRADIENT TO THE S OF THIS
INCOMING FNT...OVERNGT LO TEMPS SHOULD BE FAIRLY WARM...ESPECIALLY
IN THE DOWNSLOPE AREAS NEAR LK SUP.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 419 AM EDT TUE JUL 16 2013
STARTING OUT THE LONG TERM AT 12Z WED...THE CWA WILL BE BETWEEN AN
UPPER HIGH CENTERED OVER IN AND A LOW PRESSURE SYSTEM OVER NRN
HUDSON BAY. STRETCHING FROM THE HUDSON BAY LOW WILL BE A
TROUGH/FRONT OVER QUEBEC SW TO THE NRN CWA. THE FRONT WILL NOT MOVE
MUCH THROUGH THU...WITH SLOW SOUTHERLY MOVEMENT OR NEARLY STATIONARY
BEHAVIOR EXPECTED. WIND FIELDS WILL BE NEAR UNIDIRECTIONAL AND FOR
THE MOST PART PARALLEL TO THE FRONT. WITH INSTABILITY ALONG AND S OF
THE FRONT...EXPECT CONVECTION FOR MUCH OF THE PERIOD. TROUBLE COMES
WITH POSSIBILITIES OF STRONG TO SEVERE STORMS AND FLOODING. WINDS
PARALLEL TO THE SLOW MOVING FRONT AND PWATS OF 1.5-2.0 INCHES
/150-200 PERCENT OF NORMAL/ COMBINED WITH INSTABILITY MAY MAKE FOR
SOME AREAS RECEIVING EXCESSIVE RAINFALL...BUT IT IS TOO DIFFICULT AT
THIS TIME FRAME TO TELL WHERE EXACTLY THAT WILL BE /MORE OF A
NOWCASTING ISSUE/. AS FOR STRONG-SEVERE POTENTIAL WED-THU...THE BEST
CHANCE FOR GOOD INSTABILITY LOOKS TO BE ON WED AS THE FRONT WILL BE
MOVING INTO UPPER MI...WHILE THU LOOKS MORE UNCERTAIN SINCE THE
POSITION OF THE FRONT AND CLOUD COVER ARE MORE IN QUESTION.
FOR THE SPECIFICS FOR WED...CAPE VALUES OF 1500-2500J/KG ARE
POSSIBLE AS SFC TEMPS WARM INTO THE 80S TO AROUND 90. 0-6KM BULK
SHEAR LOOKS TO BE AROUND 30KTS /AS PREVIOUSLY STATED...THAT IS
MOSTLY UNIDIRECTIONAL/. DCAPE VALUES LOOK TO BE AOB 1000J/KG THANKS
TO SOME DRY LAYERS IN THE SOUNDING...WHICH MAY HELP GET SOME STRONG
WINDS OUT OF STORMS. MAY SEE THUNDERSTORMS INITIATE IN THE
AFTERNOON...OR COULD EVEN SEE A CONVECTIVE COMPLEX MOVE ALONG THE
FRONT. WITH WEAK SFC WINDS...MAY SEE CONVECTION FOCUSING ON LAKE
FREEZES THAT FORM. CONVECTION MAY THEN CONTINUE INTO WED NIGHT...BUT
WOULD MORE LIKELY BE ELEVATED WITH STRONG/SEVERE POTENTIAL
CONTINUING DUE TO AN INCREASE IN THE NOCTURNAL LOW LEVEL JET...BUT
IT WOULD LIKELY DEPEND MORE ON THE PATH OF ANY CONVECTIVE COMPLEXES
THAT MAY FORM.
THU...AS SAID BEFORE...MORE UNCERTAINTY WITH CONVECTIVE CHANCES DUE
TO QUESTIONS ABOUT FRONTAL LOCATION AND CLOUD COVER. SHOULD BE LESS
DCAPE AS MORE MOISTURE WILL HAVE MOVED INTO THE AREA...SO OVERALL
THINK THE CHANCE OF STRONGER/SEVERE STORMS IS MORE LIMITED THAN WED.
SHOULD SEE CONVECTION CONTINUE INTO THU NIGHT AS HEIGHT FALLS MOVE
INTO THE REGION AS THE UPPER LOW DROPS TO SRN HUDSON BAY...WHICH
WILL BOOST FORCING ACROSS THE CWA WHILE THE FRONT REMAINS FAIRLY
STATIONARY. THREAT OF HEAVY RAIN/TRAINING STORMS CONTINUES...BUT THE
LOCATION IS AGAIN NEARLY IMPOSSIBLE TO PINPOINT AT THIS TIME. SFC
TEMPS SHOULD BE COOLER IN THE 70S TO MID 80S.
FRI-SAT...THE UPPER LOW WILL WEAKEN WHILE MOVING TO JAMES BAY BY 12Z
SAT...THEN TO NRN QUEBEC BY 00Z SUN. THIS WILL ALLOW A MORE
SIGNIFICANT UPPER TROUGH TO SWING ACROSS THE CWA FRI INTO
SAT...WHICH WILL PUSH THE COLD FRONT WELL S OF THE CWA BY FRI NIGHT.
MAY STILL SEE SOME SHOWERS ON FRI AFTERNOON AS THE TROUGH PUSHES
IN...BUT TEMPS WILL BE COOLER WITH HIGHS IN THE 70S TO LOW 80S IN
MOST LOCATIONS. ALTHOUGH THE UPPER TROUGH IS STILL MOVE THROUGH
SAT...SFC HIGH PRESSURE AND ASSOCIATED DRY AIR OVER THE CWA SHOULD
KEEP THINGS DRY FOR THE MOST PART. HIGHS SAT LOOK TO BE IN THE 60S
AND 70S.
THERE IS THE POSSIBILITY OF ANOTHER TROUGH MOVING THROUGH ON SUN AND
MON /BEST CHANCES ON MON/...WHICH WOULD LEAD TO PRECIP ACROSS MUCH
OF THE CWA. HOWEVER...CONFIDENCE ON THE POSITION/TIMING/EXTENT OF
THE TROUGH IS LOW AT THIS POINT...SO WILL JUST CONTINUE TO LOAD A
CONSENSUS OF MODELS INTO FORECAST FOR THIS TIME PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 110 PM EDT TUE JUL 16 2013
VFR CONDITIONS WILL CONTINUE THROUGH THE PERIOD AT ALL SITES. ISOLD
SHRA/TS WL THEN POP UP WITH AFTERNOON HEATING AND PSBLY IMPACT SAW
BEFORE THE ARRIVAL OF DRYING ALF TENDS TO DIMINISH THIS ACTIVITY
LATE IN THE AFTN AND HAVE VCSH TO COVER THIS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 419 AM EDT TUE JUL 16 2013
WITH WEAK PRES GRADIENT AND HI STABILITY OVER THE RELATIVELY CHILLY
LAKE WATERS...EXPECT LIGHT WINDS UNDER 20 KTS THRU TONIGHT. THE
PERSISTENCE OF A FAIRLY HUMID AIRMASS OVER THE LAKE WILL RESULT IN
PATCHY FOG. A LOW PRESSURE SYSTEM AND FRONTAL BOUNDARY WILL EFFECT
THE REGION WEDNESDAY THROUGH FRIDAY...HOWEVER...WINDS SHOULD REMAIN
LIGHT AND GENERALLY LESS THAN 15 KNOTS. HIGH PRESSURE BUILDS IN FOR
MUCH OF THE WEEKEND ALLOWING WINDS TO REMAIN LIGHT AND VARIABLE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...07
MARINE...KC/TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
723 AM EDT TUE JUL 16 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 419 AM EDT TUE JUL 16 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SPRAWLING UPR RDG
CENTERED OVER THE LOWER GRT LKS. ALTHOUGH THE 00Z GRB RAOB INDICATES
THE TROPOSPHERE OVER THE UPR GRT LKS HAS MOISTENED CONSIDERABLY OVER
THE LAST DAY OR SO WITH 00Z PWAT UP TO 1.82 INCHES /185 PERCENT OF
NORMAL/...MID LVL WARMTH WITH H5 TEMPS ARND -5C HAS MAINTAINED
RATHER UNIMPRESSIVE MID LVL LAPSE RATES IN THE ABSENCE OF ANY
DYNAMIC FORCING UNDER THE RDG. THE CONVECTIVE TEMP ON THE 00Z GRB
SDNG WAS 94. A FEW -SHRA DID POP UP OVER WI YDAY AFTN...BUT THESE
DISSIPATED LAST EVNG WITH THE LOSS OF DAYTIME HEATING. HOWEVER...
MORE ISOLD -SHRA HAVE DVLPD OVER NW WI/ADJOINING MN IN AREA WHERE
RUC ANALYSIS SHOWS KINX NEAR 36. PERSISTENT BAND OF MSTR THAT HAS
PLAGUED NE MN/NW LK SUP WITH CLDS/SOME SHRA THE LAST FEW DAYS HAS
DRIFTED TO THE N INTO ONTARIO. OTRW...SFC TEMPS ARE RUNNING WELL ABV
NORMAL EARLY THIS MRNG DESPITE CLR-PCLDY SKIES. TO THE NW...THERE IS
A STRONGER SHRTWV JUST W OF LK WINNIPEG MOVING ENEWD THRU SRN CANADA.
MAIN FCST CONCERNS IN THE SHORT TERM ARE TEMPS AND SHRA/TS CHCS AS
UPR RDG REMAINS DOMINANT OVER THE GRT LKS.
TODAY...CENTER OF UPR RDG/SFC HI PRES OVER THE LOWER GRT LKS IS FCST
TO DRIFT ONLY SLOWLY TO THE W...SO MID LVL WARM AIR WL REMAIN OVER
THE CWA. STRONGER SHRTWV/ACCOMPANYING DYNAMICS LIFTING ENEWD THRU
SCENTRL CANADA WL RIDE WELL TO THE N OF UPR MI AND NOT IMPACT THE
CWA. BUT WITH DAYTIME HEATING...BULK OF NUMERICAL MODELS GENERATE
SHRA/TS OVER UPR MI TODAY. THERE ARE A NUMBER OF NEGATIVES FOR
PCPN...THE ABSENCE OF ANY DYNAMIC FORCING...FCST ACYC H85 SW FLOW
THAT WL RESULT IN ONLY WEAK LK BREEZE DVLPMENT OFF LK SUP...AND VERY
HI CONVECTIVE TEMP SHOWN ON THE 00Z GRB RAOB. HOWEVER...WITH SOME
ISOLD -SHRA OVER NW WI...SUSPECT SOME SHRA/TS WL IMPACT UPR MI
MAINLY BY LATE MRNG AFTER ONSET OF DAYTIME HEATING. FCST DRYING IN
THE AFTN IN THE WAKE OF AREA OF HIER KINX NOW MOVING TOWARD THE CWA
MAY CAUSE THE SHRA TO DIMINISH DESPITE MOVING TOWARD PEAK HEATING
TIME. THE BEST CHC FOR MORE PERSISTENT SHRA/TS WL BE OVER THE
ECENTRL CWA ON THE EDGE OF THE LK BREEZE BNDRY MOVING ONSHORE FM LK
MI. WITH FCST H85 TEMPS ARND 19C...EXPECT ANOTHER WARM DAY WITH MAX
TEMPS WELL INTO THE 80S TO LO 90S OVER THE INTERIOR. HIER HUMIDITY
WL MAKE THE AIR FEEL QUITE UNCOMFORTABLE...WITH APPARENT TEMPS
RISING TO ARND 95 AT SOME PLACES.
TNGT...COLD FNT ATTENDANT TO DISTURBANCE MOVING THRU CANADA AND INTO
HUDSON BAY IS PROGGED TO DRIFT S INTO NRN LK SUP BY 12Z WED UNDER
MODEST H5 HGT FALLS. CURRENT FCST SHOWS OVERNGT POPS OVER NRN LK SUP
CLOSE TO THIS INCOMING BNDRY AND AREA OF HIER FCST MID LVL RH...SO
WL RESTRICT FCST POPS TO THIS AREA AND KEEP THE REST OF THE CWA DRY
CLOSER TO HI PRES/CORE OF WARMER MID LVL AIR. WITH FCST H925 WINDS
UP TO 25-30 KTS UNDER SHARPENING PRES GRADIENT TO THE S OF THIS
INCOMING FNT...OVERNGT LO TEMPS SHOULD BE FAIRLY WARM...ESPECIALLY
IN THE DOWNSLOPE AREAS NEAR LK SUP.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 419 AM EDT TUE JUL 16 2013
STARTING OUT THE LONG TERM AT 12Z WED...THE CWA WILL BE BETWEEN AN
UPPER HIGH CENTERED OVER IN AND A LOW PRESSURE SYSTEM OVER NRN
HUDSON BAY. STRETCHING FROM THE HUDSON BAY LOW WILL BE A
TROUGH/FRONT OVER QUEBEC SW TO THE NRN CWA. THE FRONT WILL NOT MOVE
MUCH THROUGH THU...WITH SLOW SOUTHERLY MOVEMENT OR NEARLY STATIONARY
BEHAVIOR EXPECTED. WIND FIELDS WILL BE NEAR UNIDIRECTIONAL AND FOR
THE MOST PART PARALLEL TO THE FRONT. WITH INSTABILITY ALONG AND S OF
THE FRONT...EXPECT CONVECTION FOR MUCH OF THE PERIOD. TROUBLE COMES
WITH POSSIBILITIES OF STRONG TO SEVERE STORMS AND FLOODING. WINDS
PARALLEL TO THE SLOW MOVING FRONT AND PWATS OF 1.5-2.0 INCHES
/150-200 PERCENT OF NORMAL/ COMBINED WITH INSTABILITY MAY MAKE FOR
SOME AREAS RECEIVING EXCESSIVE RAINFALL...BUT IT IS TOO DIFFICULT AT
THIS TIME FRAME TO TELL WHERE EXACTLY THAT WILL BE /MORE OF A
NOWCASTING ISSUE/. AS FOR STRONG-SEVERE POTENTIAL WED-THU...THE BEST
CHANCE FOR GOOD INSTABILITY LOOKS TO BE ON WED AS THE FRONT WILL BE
MOVING INTO UPPER MI...WHILE THU LOOKS MORE UNCERTAIN SINCE THE
POSITION OF THE FRONT AND CLOUD COVER ARE MORE IN QUESTION.
FOR THE SPECIFICS FOR WED...CAPE VALUES OF 1500-2500J/KG ARE
POSSIBLE AS SFC TEMPS WARM INTO THE 80S TO AROUND 90. 0-6KM BULK
SHEAR LOOKS TO BE AROUND 30KTS /AS PREVIOUSLY STATED...THAT IS
MOSTLY UNIDIRECTIONAL/. DCAPE VALUES LOOK TO BE AOB 1000J/KG THANKS
TO SOME DRY LAYERS IN THE SOUNDING...WHICH MAY HELP GET SOME STRONG
WINDS OUT OF STORMS. MAY SEE THUNDERSTORMS INITIATE IN THE
AFTERNOON...OR COULD EVEN SEE A CONVECTIVE COMPLEX MOVE ALONG THE
FRONT. WITH WEAK SFC WINDS...MAY SEE CONVECTION FOCUSING ON LAKE
FREEZES THAT FORM. CONVECTION MAY THEN CONTINUE INTO WED NIGHT...BUT
WOULD MORE LIKELY BE ELEVATED WITH STRONG/SEVERE POTENTIAL
CONTINUING DUE TO AN INCREASE IN THE NOCTURNAL LOW LEVEL JET...BUT
IT WOULD LIKELY DEPEND MORE ON THE PATH OF ANY CONVECTIVE COMPLEXES
THAT MAY FORM.
THU...AS SAID BEFORE...MORE UNCERTAINTY WITH CONVECTIVE CHANCES DUE
TO QUESTIONS ABOUT FRONTAL LOCATION AND CLOUD COVER. SHOULD BE LESS
DCAPE AS MORE MOISTURE WILL HAVE MOVED INTO THE AREA...SO OVERALL
THINK THE CHANCE OF STRONGER/SEVERE STORMS IS MORE LIMITED THAN WED.
SHOULD SEE CONVECTION CONTINUE INTO THU NIGHT AS HEIGHT FALLS MOVE
INTO THE REGION AS THE UPPER LOW DROPS TO SRN HUDSON BAY...WHICH
WILL BOOST FORCING ACROSS THE CWA WHILE THE FRONT REMAINS FAIRLY
STATIONARY. THREAT OF HEAVY RAIN/TRAINING STORMS CONTINUES...BUT THE
LOCATION IS AGAIN NEARLY IMPOSSIBLE TO PINPOINT AT THIS TIME. SFC
TEMPS SHOULD BE COOLER IN THE 70S TO MID 80S.
FRI-SAT...THE UPPER LOW WILL WEAKEN WHILE MOVING TO JAMES BAY BY 12Z
SAT...THEN TO NRN QUEBEC BY 00Z SUN. THIS WILL ALLOW A MORE
SIGNIFICANT UPPER TROUGH TO SWING ACROSS THE CWA FRI INTO
SAT...WHICH WILL PUSH THE COLD FRONT WELL S OF THE CWA BY FRI NIGHT.
MAY STILL SEE SOME SHOWERS ON FRI AFTERNOON AS THE TROUGH PUSHES
IN...BUT TEMPS WILL BE COOLER WITH HIGHS IN THE 70S TO LOW 80S IN
MOST LOCATIONS. ALTHOUGH THE UPPER TROUGH IS STILL MOVE THROUGH
SAT...SFC HIGH PRESSURE AND ASSOCIATED DRY AIR OVER THE CWA SHOULD
KEEP THINGS DRY FOR THE MOST PART. HIGHS SAT LOOK TO BE IN THE 60S
AND 70S.
THERE IS THE POSSIBILITY OF ANOTHER TROUGH MOVING THROUGH ON SUN AND
MON /BEST CHANCES ON MON/...WHICH WOULD LEAD TO PRECIP ACROSS MUCH
OF THE CWA. HOWEVER...CONFIDENCE ON THE POSITION/TIMING/EXTENT OF
THE TROUGH IS LOW AT THIS POINT...SO WILL JUST CONTINUE TO LOAD A
CONSENSUS OF MODELS INTO FORECAST FOR THIS TIME PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 722 AM EDT TUE JUL 16 2013
A TS MOVING NEWD ALONG THE W COAST OF UPR MI WL IMPACT CMX EARLY IN
THE FCST PERIOD WITH SOME GUSTY WINDS/BRIEF +SHRA. MORE ISOLD
SHRA/TS WL THEN POPUP WITH DAYTIME HEATING AND PSBLY IMPACT THE TAF
SITES BEFORE THE ARRIVAL OF DRYING ALF TENDS TO DIMINISH THIS
ACTIVITY IN THE AFTN. CONFIDENCE IN TIMING/PLACEMENT OF ANY OF THESE
SHRA/TS IS TOO LO TO INCLUDE IN ANY OF THE TAFS RIGHT NOW. WITH
DAYTIME HEATING/MIXING...A GUSTY SW WIND WL DVLP. EXCEPT FOR UNDER
THE HEAVIER SHRA...VFR CONDITIONS WL PREDOMINATE.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 419 AM EDT TUE JUL 16 2013
WITH WEAK PRES GRADIENT AND HI STABILITY OVER THE RELATIVELY CHILLY
LAKE WATERS...EXPECT LIGHT WINDS UNDER 20 KTS THRU TONIGHT. THE
PERSISTENCE OF A FAIRLY HUMID AIRMASS OVER THE LAKE WILL RESULT IN
PATCHY FOG. A LOW PRESSURE SYSTEM AND FRONTAL BOUNDARY WILL EFFECT
THE REGION WEDNESDAY THROUGH FRIDAY...HOWEVER...WINDS SHOULD REMAIN
LIGHT AND GENERALLY LESS THAN 15 KNOTS. HIGH PRESSURE BUILDS IN FOR
MUCH OF THE WEEKEND ALLOWING WINDS TO REMAIN LIGHT AND VARIABLE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...KC
MARINE...KC/TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
420 AM EDT TUE JUL 16 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 419 AM EDT TUE JUL 16 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SPRAWLING UPR RDG
CENTERED OVER THE LOWER GRT LKS. ALTHOUGH THE 00Z GRB RAOB INDICATES
THE TROPOSPHERE OVER THE UPR GRT LKS HAS MOISTENED CONSIDERABLY OVER
THE LAST DAY OR SO WITH 00Z PWAT UP TO 1.82 INCHES /185 PERCENT OF
NORMAL/...MID LVL WARMTH WITH H5 TEMPS ARND -5C HAS MAINTAINED
RATHER UNIMPRESSIVE MID LVL LAPSE RATES IN THE ABSENCE OF ANY
DYNAMIC FORCING UNDER THE RDG. THE CONVECTIVE TEMP ON THE 00Z GRB
SDNG WAS 94. A FEW -SHRA DID POP UP OVER WI YDAY AFTN...BUT THESE
DISSIPATED LAST EVNG WITH THE LOSS OF DAYTIME HEATING. HOWEVER...
MORE ISOLD -SHRA HAVE DVLPD OVER NW WI/ADJOINING MN IN AREA WHERE
RUC ANALYSIS SHOWS KINX NEAR 36. PERSISTENT BAND OF MSTR THAT HAS
PLAGUED NE MN/NW LK SUP WITH CLDS/SOME SHRA THE LAST FEW DAYS HAS
DRIFTED TO THE N INTO ONTARIO. OTRW...SFC TEMPS ARE RUNNING WELL ABV
NORMAL EARLY THIS MRNG DESPITE CLR-PCLDY SKIES. TO THE NW...THERE IS
A STRONGER SHRTWV JUST W OF LK WINNIPEG MOVING ENEWD THRU SRN CANADA.
MAIN FCST CONCERNS IN THE SHORT TERM ARE TEMPS AND SHRA/TS CHCS AS
UPR RDG REMAINS DOMINANT OVER THE GRT LKS.
TODAY...CENTER OF UPR RDG/SFC HI PRES OVER THE LOWER GRT LKS IS FCST
TO DRIFT ONLY SLOWLY TO THE W...SO MID LVL WARM AIR WL REMAIN OVER
THE CWA. STRONGER SHRTWV/ACCOMPANYING DYNAMICS LIFTING ENEWD THRU
SCENTRL CANADA WL RIDE WELL TO THE N OF UPR MI AND NOT IMPACT THE
CWA. BUT WITH DAYTIME HEATING...BULK OF NUMERICAL MODELS GENERATE
SHRA/TS OVER UPR MI TODAY. THERE ARE A NUMBER OF NEGATIVES FOR
PCPN...THE ABSENCE OF ANY DYNAMIC FORCING...FCST ACYC H85 SW FLOW
THAT WL RESULT IN ONLY WEAK LK BREEZE DVLPMENT OFF LK SUP...AND VERY
HI CONVECTIVE TEMP SHOWN ON THE 00Z GRB RAOB. HOWEVER...WITH SOME
ISOLD -SHRA OVER NW WI...SUSPECT SOME SHRA/TS WL IMPACT UPR MI
MAINLY BY LATE MRNG AFTER ONSET OF DAYTIME HEATING. FCST DRYING IN
THE AFTN IN THE WAKE OF AREA OF HIER KINX NOW MOVING TOWARD THE CWA
MAY CAUSE THE SHRA TO DIMINISH DESPITE MOVING TOWARD PEAK HEATING
TIME. THE BEST CHC FOR MORE PERSISTENT SHRA/TS WL BE OVER THE
ECENTRL CWA ON THE EDGE OF THE LK BREEZE BNDRY MOVING ONSHORE FM LK
MI. WITH FCST H85 TEMPS ARND 19C...EXPECT ANOTHER WARM DAY WITH MAX
TEMPS WELL INTO THE 80S TO LO 90S OVER THE INTERIOR. HIER HUMIDITY
WL MAKE THE AIR FEEL QUITE UNCOMFORTABLE...WITH APPARENT TEMPS
RISING TO ARND 95 AT SOME PLACES.
TNGT...COLD FNT ATTENDANT TO DISTURBANCE MOVING THRU CANADA AND INTO
HUDSON BAY IS PROGGED TO DRIFT S INTO NRN LK SUP BY 12Z WED UNDER
MODEST H5 HGT FALLS. CURRENT FCST SHOWS OVERNGT POPS OVER NRN LK SUP
CLOSE TO THIS INCOMING BNDRY AND AREA OF HIER FCST MID LVL RH...SO
WL RESTRICT FCST POPS TO THIS AREA AND KEEP THE REST OF THE CWA DRY
CLOSER TO HI PRES/CORE OF WARMER MID LVL AIR. WITH FCST H925 WINDS
UP TO 25-30 KTS UNDER SHARPENING PRES GRADIENT TO THE S OF THIS
INCOMING FNT...OVERNGT LO TEMPS SHOULD BE FAIRLY WARM...ESPECIALLY
IN THE DOWNSLOPE AREAS NEAR LK SUP.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 419 AM EDT TUE JUL 16 2013
STARTING OUT THE LONG TERM AT 12Z WED...THE CWA WILL BE BETWEEN AN
UPPER HIGH CENTERED OVER IN AND A LOW PRESSURE SYSTEM OVER NRN
HUDSON BAY. STRETCHING FROM THE HUDSON BAY LOW WILL BE A
TROUGH/FRONT OVER QUEBEC SW TO THE NRN CWA. THE FRONT WILL NOT MOVE
MUCH THROUGH THU...WITH SLOW SOUTHERLY MOVEMENT OR NEARLY STATIONARY
BEHAVIOR EXPECTED. WIND FIELDS WILL BE NEAR UNIDIRECTIONAL AND FOR
THE MOST PART PARALLEL TO THE FRONT. WITH INSTABILITY ALONG AND S OF
THE FRONT...EXPECT CONVECTION FOR MUCH OF THE PERIOD. TROUBLE COMES
WITH POSSIBILITIES OF STRONG TO SEVERE STORMS AND FLOODING. WINDS
PARALLEL TO THE SLOW MOVING FRONT AND PWATS OF 1.5-2.0 INCHES
/150-200 PERCENT OF NORMAL/ COMBINED WITH INSTABILITY MAY MAKE FOR
SOME AREAS RECEIVING EXCESSIVE RAINFALL...BUT IT IS TOO DIFFICULT AT
THIS TIME FRAME TO TELL WHERE EXACTLY THAT WILL BE /MORE OF A
NOWCASTING ISSUE/. AS FOR STRONG-SEVERE POTENTIAL WED-THU...THE BEST
CHANCE FOR GOOD INSTABILITY LOOKS TO BE ON WED AS THE FRONT WILL BE
MOVING INTO UPPER MI...WHILE THU LOOKS MORE UNCERTAIN SINCE THE
POSITION OF THE FRONT AND CLOUD COVER ARE MORE IN QUESTION.
FOR THE SPECIFICS FOR WED...CAPE VALUES OF 1500-2500J/KG ARE
POSSIBLE AS SFC TEMPS WARM INTO THE 80S TO AROUND 90. 0-6KM BULK
SHEAR LOOKS TO BE AROUND 30KTS /AS PREVIOUSLY STATED...THAT IS
MOSTLY UNIDIRECTIONAL/. DCAPE VALUES LOOK TO BE AOB 1000J/KG THANKS
TO SOME DRY LAYERS IN THE SOUNDING...WHICH MAY HELP GET SOME STRONG
WINDS OUT OF STORMS. MAY SEE THUNDERSTORMS INITIATE IN THE
AFTERNOON...OR COULD EVEN SEE A CONVECTIVE COMPLEX MOVE ALONG THE
FRONT. WITH WEAK SFC WINDS...MAY SEE CONVECTION FOCUSING ON LAKE
FREEZES THAT FORM. CONVECTION MAY THEN CONTINUE INTO WED NIGHT...BUT
WOULD MORE LIKELY BE ELEVATED WITH STRONG/SEVERE POTENTIAL
CONTINUING DUE TO AN INCREASE IN THE NOCTURNAL LOW LEVEL JET...BUT
IT WOULD LIKELY DEPEND MORE ON THE PATH OF ANY CONVECTIVE COMPLEXES
THAT MAY FORM.
THU...AS SAID BEFORE...MORE UNCERTAINTY WITH CONVECTIVE CHANCES DUE
TO QUESTIONS ABOUT FRONTAL LOCATION AND CLOUD COVER. SHOULD BE LESS
DCAPE AS MORE MOISTURE WILL HAVE MOVED INTO THE AREA...SO OVERALL
THINK THE CHANCE OF STRONGER/SEVERE STORMS IS MORE LIMITED THAN WED.
SHOULD SEE CONVECTION CONTINUE INTO THU NIGHT AS HEIGHT FALLS MOVE
INTO THE REGION AS THE UPPER LOW DROPS TO SRN HUDSON BAY...WHICH
WILL BOOST FORCING ACROSS THE CWA WHILE THE FRONT REMAINS FAIRLY
STATIONARY. THREAT OF HEAVY RAIN/TRAINING STORMS CONTINUES...BUT THE
LOCATION IS AGAIN NEARLY IMPOSSIBLE TO PINPOINT AT THIS TIME. SFC
TEMPS SHOULD BE COOLER IN THE 70S TO MID 80S.
FRI-SAT...THE UPPER LOW WILL WEAKEN WHILE MOVING TO JAMES BAY BY 12Z
SAT...THEN TO NRN QUEBEC BY 00Z SUN. THIS WILL ALLOW A MORE
SIGNIFICANT UPPER TROUGH TO SWING ACROSS THE CWA FRI INTO
SAT...WHICH WILL PUSH THE COLD FRONT WELL S OF THE CWA BY FRI NIGHT.
MAY STILL SEE SOME SHOWERS ON FRI AFTERNOON AS THE TROUGH PUSHES
IN...BUT TEMPS WILL BE COOLER WITH HIGHS IN THE 70S TO LOW 80S IN
MOST LOCATIONS. ALTHOUGH THE UPPER TROUGH IS STILL MOVE THROUGH
SAT...SFC HIGH PRESSURE AND ASSOCIATED DRY AIR OVER THE CWA SHOULD
KEEP THINGS DRY FOR THE MOST PART. HIGHS SAT LOOK TO BE IN THE 60S
AND 70S.
THERE IS THE POSSIBILITY OF ANOTHER TROUGH MOVING THROUGH ON SUN AND
MON /BEST CHANCES ON MON/...WHICH WOULD LEAD TO PRECIP ACROSS MUCH
OF THE CWA. HOWEVER...CONFIDENCE ON THE POSITION/TIMING/EXTENT OF
THE TROUGH IS LOW AT THIS POINT...SO WILL JUST CONTINUE TO LOAD A
CONSENSUS OF MODELS INTO FORECAST FOR THIS TIME PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 122 AM EDT TUE JUL 16 2013
WITH HIGH PRESSURE IN PLACE OVER UPPER MICHIGAN...EXPECT VFR
CONDITIONS THROUGH MOST OF THE TAF PERIOD. THE ONLY CONCERN WILL BE
THE POTENTIAL FOR FOG DEVELOPMENT EARLY THIS MORNING. THOUGH DEW
POINTS ARE MOIST (IN THE LOWER 60S) AND SKIES CLEAR...FOG MAY BE
LIMITED SOMEWHAT DUE TO DEVELOPING SOUTHERLY BOUNDARY LAYER WINDS TO
15-20 KT. WILL INCLUDE MVFR VSBYS FOR ALL TAF SITES FM 09-12Z BUT
MIXING FM STRONGER BOUNDARY LAYER WINDS SHOULD ALLOW IMPROVEMENT
AROUND SUNRISE.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 419 AM EDT TUE JUL 16 2013
WITH WEAK PRES GRADIENT AND HI STABILITY OVER THE RELATIVELY CHILLY
LAKE WATERS...EXPECT LIGHT WINDS UNDER 20 KTS THRU TONIGHT. THE
PERSISTENCE OF A FAIRLY HUMID AIRMASS OVER THE LAKE WILL RESULT IN
PATCHY FOG. A LOW PRESSURE SYSTEM AND FRONTAL BOUNDARY WILL EFFECT
THE REGION WEDNESDAY THROUGH FRIDAY...HOWEVER...WINDS SHOULD REMAIN
LIGHT AND GENERALLY LESS THAN 15 KNOTS. HIGH PRESSURE BUILDS IN FOR
MUCH OF THE WEEKEND ALLOWING WINDS TO REMAIN LIGHT AND VARIABLE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...VOSS
MARINE...KC/TITUS
AREA FORECAST DISCUSSION...UPDATE
NWS JACKSON MS
855 PM CDT WED JUL 17 2013
...STRONG TO SEVERE STORMS POSSIBLE TOMORROW AFTN/ERLY EVE...
.UPDATE...SMALL DISTURBANCE PRECEDING LARGER DISTURBANCE
UNDERCUTTING RIDGE TO OUR NORTH HAS BEEN RESPONSIBLE FOR KICKING OFF
SCATTERED (AND OCCASIONALLY POTENT) THUNDERSTORMS THIS AFTERNOON
UNTIL JUST RECENTLY OVER SOUTHERN PORTIONS OF THE FORECAST AREA.
THIS SMALL DISTURBANCE IS MOVING OFF TO THE WEST AND GETTING READY
TO CLEAR THE REGION...ALTHOUGH A STRAY SHOWER OR STORM CANNOT BE
RULED OUT OVER THE NEXT FEW HOURS IN SOUTHWESTERN ZONES.
LATER TONIGHT THE WESTERN FRINGES OF THE LARGER DISTURBANCE (TUTT
TYPE LOW) WILL BE MOVING IN FROM THE EAST. PREVIOUS DISCUSSION
TALKED OF HOW MODELS HAD BEEN DOWNPLAYING ANY REDEVELOPMENT OF
CONVECTION IN OUR REGION LATE TONIGHT IN ASSOCIATION WITH THE
APPROACHING LOW ALOFT. HOWEVER...LATEST HRRR RUNS SHOW AT LEAST SOME
ISOLATED CONVECTION IN EASTERN MS LATE TONIGHT...AND THIS SEEMS
FEASIBLE GIVEN MODEL INSTABILITY OUTPUT AND THE FACT THAT SHOWERS
AND STORMS ARE NOW INCREASING IN EASTERN ALABAMA (AND MIGRATING
SLOWLY THIS DIRECTION). THUS...FORECAST FOR LATE TONIGHT THROUGH THE
MORNING HOURS TOMORROW UPDATED TO INCLUDE MENTION OF ISOLATED
SHOWERS/STORMS GRADUALLY SPREADING WEST. GIVEN STABILIZING BOUNDARY
LAYER LATE TONIGHT ANY ELEVATED INSTABILITY DRIVING STORM
DEVELOPMENT (IF SUCH OCCURS) SHOULD IMPART MINIMAL POTENTIAL FOR
HAZARDOUS WEATHER...ALTHOUGH LOCALIZED HEAVY DOWNPOURS ARE CERTAINLY
POSSIBLE. /BB/
&&
.PREV DISCUSSION... /ISSUED 412 PM CDT WED JUL 17 2013/
DISCUSSION...SHOWERS AND A FEW THUNDERSTORMS ARE ONGOING ACROSS
SOUTH MS AND PORTIONS OF NE LA AS AFTERNOON CONVECTIVE TEMPERATURES
ARE BEING REACHED IN THE LOW TO MID 90S. SHOWER/STORM COVERAGE IS
NOT GREAT ACROSS THE REGION, AS EXPECTED, WITH SYNOPTIC SUBSIDENCE
PREVAILING AS A RESULT OF H5 RIDGE INFLUENCE CENTERED OVER THE OHIO
VALLEY. ANOTHER NOTABLE FEATURE IS A DEVELOPING TUTT LOW AND
ASSOCIATED S/WV VORTICITY IMPULSES TRAPPED IN THE EASTERLY MID-LVL
FLOW ON THE SOUTHERN PERIPHERY OF THE LARGE H5 RIDGE ACROSS THE WRN
GOM AND SOUTHERN ATLANTIC SEABOARD. THIS TUTT WILL AID IN THE STORMS
TOMORROW.
CURRENT SHOWER AND THUNDERSTORM ACTIVITY WILL SLOWLY DIMINISH
THROUGH THE EARLY EVENING HOURS AS THE ATMOSPHERE DESTABILIZES BUT AN
OUTSIDE STRONG STORM MAY BE POSSIBLE IF MERGERS OCCUR. THE POTENTIAL
FOR STRONG STORMS ACROSS FAR EAST MS TONIGHT HAS BEEN DECREASING WITH
ACTIVITY REMAINING CONFINED IN GA THIS AFTN AND STRUGGLING FARTHER
WEST IN AL WITH A DIMINISHING CU FIELD. LOCAL WRF AND HRRR SUPPORT
THIS THINKING AND HAVE ADJUSTED POPS/WX FOR THE OVRNGT PERIOD
ACCORDINGLY.
AS TUTT LOW INFLUENCE INCREASES TOMORROW, A NOTABLE LOW-LVL
CONVERGENT WIND FIELD LOOKS TO DEVELOP, CREATING AN INITIAL
CONVECTIVE TRIGGERING MECHANISM. A MORE THAN SUPPORTIVE THERMO
ENVIRONMENT LOOKS TO BE IN PLACE WITH >3000 J/KG SBCAPE, 27-28C
VERTICAL TOTALS AND STEEP LOW-LVL LAPSE RATES WITH TOMORROW LIKELY
THE WARMEST OF THE WEEK AS READINGS CLIMB INTO THE MID 90S. IT`S
TOUGH TO PINPOINT WHAT AREA WILL BE MORE FAVORED FOR SCATTERED TO
NUMEROUS STORM DEVELOPMENT AS IT WILL DEPEND ON H5 INVERTED TROUGH
AXIS LOCATION AND SPEED. NAM AND SUBSEQUENT HI-RES OUTPUT BASED ON
ITS INITIAL CONDITIONS ARE A BIT FASTER THAN GFS AND DEPICT BEST
COVERAGE IN CENTRAL AND WEST AREAS WITH GFS A TOUCH SLOWER WITH
POTENTIAL GREATER COVERAGE IN THE EAST. HAVE BLENDED THE TWO (WHICH
IS MUCH HIGHER THAN MAV POPS SUGGEST AND FOLLOWED MUCH CLOSER TO MET
GUIDANCE FOR THURS AFTN PERIOD. GIVEN HIGH LAPSE RATES AND ADEQUATE
INSTABILITY, STRAIGHT LINE WINDS OF 60 MPH, HAIL, AND HEAVY
DOWNPOURS WILL BE LIKELY INVOF STRONGEST STORMS. STORM MOTION WILL
BE SLOW AS ATM COLUMN HAS LITTLE FLOW, FURTHER AIDING IN LOCALIZED
POTENTIAL FOR FLASH FLOODING. ACTIVITY WILL SLOWLY DIMINISH THROUGH
THE MID TO LATE LATE EVE AS THE MID-UPPER LOW TRAVERSES WEST ACROSS
THE SABINE RIVER.
FOR FRIDAY...ANOTHER ROUND OF DECENT COVERAGE OF SHOWERS AND STORMS
AS CONTINUED FAVORABLE LIFT AND INSTABILITY REMAIN IN THE AREA WITH
THE TUTT LOW OVER ERN TX. SOME STORMS DURING FRI AFTN COULD AT LEAST
BE ON THE STRONG SIDE AND WILL HAVE TO MONITOR MESOSCALE EVOLUTION
THURSDAY TO SEE IF SEVERE STORMS COULD BE ATTAINED FRIDAY. HAVE
ADDED WORDING TO THE HWO/GRAPHICS FOR FRIDAY AFTN FOR THIS STRONG
STORM POTENTIAL.
FOR FORECAST ELEMENTS...MET POPS WERE USED AS A STARTING POINT FOR
TOMORROW IN LIEU OF LOW MAV POPS. POPS WERE ALSO BOOSTED FRIDAY WITH
WEAKNESS IN THE RIDGE AND TUTT LOW INFLUENCE. MAV LOW TEMPS WERE
BUMPED UP 1-3F DEGREES WITH HIGHS BUMPED DOWN 2F DEGREES BASED ON
RECENT TRENDS. /ALLEN/
&&
.AVIATION...MAINLY VFR CONDITIONS ARE ANTICIPATED THROUGH TONIGHT
AND INTO THE MORNING HOURS. HOWEVER...THERE WILL BE THE POTENTIAL
FOR ISOLATED SHOWERS/STORMS LATE TONIGHT IN EASTERN MS AND IN ALL
AREAS TOMORROW MORNING. CHANCES FOR ANY OF THIS ACTIVITY HITTING TAF
SITES RATHER LOW...BUT IF IT OCCURS THEN BRIEF IFR CONDITIONS IN
THIS TIME PERIOD NOT IMPOSSIBLE. OTHERWISE...A MUCH GREATER COVERAGE
OF CONVECTION AREAWIDE TOMORROW AFTERNOON INTO TOMORROW EVENING
ALTHOUGH AWAY FROM STORMS IN THIS PERIOD MOST FLIGHT CATS SHOULD
STILL REMAIN VFR. /BB/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 72 93 72 93 / 12 39 21 39
MERIDIAN 69 93 72 93 / 14 30 21 38
VICKSBURG 69 93 72 93 / 11 46 22 38
HATTIESBURG 72 93 73 93 / 14 42 21 44
NATCHEZ 70 91 72 91 / 14 46 21 48
GREENVILLE 74 95 74 94 / 10 46 20 37
GREENWOOD 72 94 72 94 / 11 30 17 40
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
BB/ALLEN
AREA FORECAST DISCUSSION
NWS GLASGOW MT
923 PM MDT WED JUL 17 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH FRIDAY
EVENING UPDATE...
MAIN CHANGE FOR THIS EVENING WAS TO GO IN AND ADD POPS ACROSS THE
FAR WESTERN PORTION OF THE CWA TO ACCOUNT FOR THE INCOMING RADAR
ECHOS AS OF 9PM. THESE SHOWERS AND THUNDERSTORMS ARE BEING
PARTIALLY DRIVEN BY AN MID LEVEL SHORTWAVE EVIDENT ON WATER VAPOR
IMAGERY AND STRONG DAYTIME CAPE ACROSS CENTRAL PORTIONS OF MONTANA.
THE STORMS HOWEVER ARE EXPECTED TO WANE AS SUN SETS AND AS CAP
BECOMES FAR STRONGER WITH A STABILIZED SURFACE LAYER FROM RAIN
EARLIER IN THE DAY. PETROLEUM COUNTY WILL PROBABLY EXPERIENCE THE
MOST RAIN THIS EVENING LOOKING AT RADAR TRENDS. GAH
PREVIOUS SHORT TERM DISCUSSION...
MAIN CHALLENGE THIS AFTERNOON AND EVENING IS THE HIGH TEMPERATURE
FORECAST ACROSS THE CWA. ACROSS THE NORTHEAST...DECIDED TO LOWER
TEMPERATURES BY SEVERAL DEGREES BELOW 17/12Z GUIDANCE GIVEN THE
PERSISTENT STEADY SHOWERS AND CLOUD COVER THERE. ACROSS CENTRAL
PORTIONS OF THE CWA...AREAS SHOULD START TO SEE BREAKS OF SUNSHINE
WHICH WILL RESULT IN TEMPERATURES RESPONDING. DID LOWER HIGHS IN A
FEW LOCATIONS AS THERE ARE ONLY A FEW HOURS OF DAYTIME HEATING
REMAINING. IN SHORT...EXPECT 80 DEGREES OR BETTER LATE AFTERNOON
OR EVENING ACROSS THE SOUTHERN ZONES. TEMPERATURES SHOULD MAKE IT
TO THE LOWER TO MIDDLE 70S ACROSS CENTRAL PORTIONS OF THE FORECAST
AREA. ONLY EXPECT HIGHS TO REACH UPPER 60S AND NEAR 70 ACROSS THE
INTERNATIONAL BORDER AND IN THE FAR NORTHEAST.
TONIGHT...TRICKY FORECAST REGARDING POTENTIAL SHOWER ACTIVITY
DEVELOPING...PRIMARILY SOUTH OF THE MISSOURI RIVER. WILL INSERT
LOW END CHANCE POPS FOR NOW BUT THE NEXT SHIFT WILL HAVE TO
MONITOR FAIRLY CAREFULLY FOR UPDATES. THE LATEST GFS/ECMWF MODELS
ARE DRY BUT THE NAM AND HRRR SHOWS POTENTIAL FOR PRECIPITATION
TONIGHT ACROSS THE SOUTH. GIVEN MORE SUNSHINE DURING THE DAYTIME
ACROSS THOSE LOCATIONS THERE COULD BE A BIT MORE INSTABILITY TO
TAP AS WEAK SHORTWAVE ENERGY PUSHES THROUGH OVERNIGHT. GIVEN LACK
OF CONFIDENCE HOWEVER...DID NOT GO TOO AGGRESSIVE AT THIS TIME.
THURSDAY...UPPER LEVEL ZONAL FLOW IN THE MORNING WILL TRANSITION
TO NORTHWEST FLOW ALOFT AS A SHORTWAVE TRAVELING ACROSS THE
INTERNATIONAL BORDER CLIPS THE NORTHEASTERN ZONES AND SWEEPS A
SURFACE COLD FRONT THROUGH THE CWA. WILL EXPECT STRONG GUSTY WINDS
TO DEVELOP BEHIND THE FRONTAL PASSAGE. NAM BUFKIT SOUNDINGS
INDICATE 40 KTS IN THE MID LEVELS. GIVEN VERY GOOD LOW AND MID
LEVEL LAPSE RATES...SOME OF THESE GUSTS MAY MIX DOWN TO THE
SURFACE. EXPECT 20-25 MPH SUSTAINED WINDS WITH GUSTS TO 35 MPH TO
BE QUITE POSSIBLE...WITH ISOLATED HIGHER GUSTS. THEREFORE...WILL
HOIST A LAKE WIND ADVISORY BEGINNING AT 15Z AND HAVE IT EXPIRE AT
MIDNIGHT WHEN WINDS ARE EXPECTED TO RELAX. MAINTAINED CHANCE POPS
IN THE NORTHEAST CLOSER TO THE WAVE AND THE AREA OF BEST PVA.
DESPITE THE FRONTAL PASSAGE...HIGHS MAY PROVE TO BE WARMER ACROSS
THE NORTHEAST DUE TO MORE IN THE WAY OF SUNSHINE.
THURSDAY NIGHT AND FRIDAY...NORTHWEST FLOW ALOFT WILL CONTINUE
ACROSS THE FORECAST REGION AND SHORTWAVE ENERGY WILL PROPAGATE
THROUGH ON FRIDAY BRINGING ADDITIONAL CHANCES FOR SHOWERS AND
POSSIBLY THUNDER IN THE NORTHEAST. IT SHOULD REMAIN FAIRLY DRY
THURSDAY NIGHT AND FRIDAY ACROSS A ROBUST PORTION OF THE FORECAST
AREA HOWEVER AS THE CWA IS EXPECTED TO SIT ON THE EXTREME
NORTHEAST PERIPHERY OF A RIDE DOMINATING THE SOUTHWESTERN STATES.
THE ONLY AREA OF CONCERN WILL BE THE NORTHEAST CORNER OF THE
FORECAST AREA WHERE SHORTWAVE ENERGY RIDING AROUND THE RIDGE MAY
LEAD TO ENHANCED VERTICAL ASCENT AND TRIGGER A FEW SHOWERS AND/OR
THUNDERSTORMS. THIS IS STILL A COUPLE OF DAYS OUT AND FUTURE
SHIFTS CAN EVALUATE POTENTIAL FURTHER. MALIAWCO
.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...
GOING FORECAST WAS IN GREAT SHAPE AND ONLY TWEAK MADE WAS TO
INCREASE POPS SLIGHTLY FOR MONDAY. JAMBA
PREVIOUS DISCUSSION...
BOTH THE EC AND THE GFS SHOW NORTHEAST MONTANA REMAINING UNDER A
NORTHWESTERLY FLOW ALOFT...AT LEAST THROUGH SUNDAY NIGHT...DUE TO
A PERSISTENT HEAT DOME OF HIGH PRESSURE CENTERED OVER THE GREAT
BASIN SUPPORTING A RIDGE IN THE WEST.
HOWEVER BEGINNING SUNDAY NIGHT THE 2 MODELS QUIT RESEMBLING EACH
OTHER. THE BIG DIFFERENCE IS THAT THE 12Z EC PICKS UP A COMPACT
CYCLONE OFF THE PACIFIC NORTHWEST COAST AND EJECTS IT ACROSS THE
INTER-MOUNTAIN WEST AND CANADIAN ROCKIES INTO ALBERTA AND
SASKATCHEWAN. THIS ACTION WOULD BACK FLOW ALOFT TO THE SOUTHWEST
AND SEND A COLD FRONT ACROSS THE DIVIDE TO REACH NEMONT AROUND
MONDAY NIGHT. THE GFS SHOWS NO HINT OF THIS WAVE. THEREFORE AFTER
THE WEEKEND THERE IS MORE UNCERTAINTY AS TO WHICH MODEL WILL PLAY
OUT. LATER IN THE SHIFT THE DELAYED 00Z EC STILL HOLDS ONTO THE
SHORTWAVE DISTURBANCE BUT RUNS IT EAST THROUGH MONTANA. WITH MORE
CONSISTENCY...REMAINED MOSTLY WITH THE GFS SOLUTION FOR THE REST
OF THE FORECAST.
FRIDAY NIGHT THROUGH SUNDAY NIGHT...WITH HIGH PRESSURE TO THE
SOUTHWEST AND A STRONG CLOSED UPPER LOW ROTATING AROUND HUDSON
BAY...NORTHEAST MONTANA WILL HAVE THE STATIONARY COLD BOUNDARY TO
THE NORTHEAST AND DESERT AIR TRYING TO PUSH IN FROM THE SOUTH.
THIS PATTERN MIGHT SEE SOME OVERRUNNING MOISTURE NEAR THIS
BOUNDARY FIRING OFF A FEW THUNDERSTORMS. BUT FOR THE MOST
PART...DRY WARM AIR WILL BE THE MAIN FEATURE OF THE WEEKEND.
MONDAY AND BEYOND...WITH BOTH MODELS OUT OF PHASE WITH EACH
OTHER...WILL NOT MOVE MUCH ONE WAY OR THE OTHER FROM THE
INHERITED GRIDS. TEMPERATURE SHOULD BE VERY WARM ON MONDAY...AND
IF THE RIDGE HOLDS THE HIGHS WILL REMAIN VERY WARM. THE EC BRINGS
IN A FRONT AROUND MONDAY NIGHT WHICH WILL TEND TO COOL
TEMPERATURES AND ALSO BRING A BETTER CHANCE FOR STRONG
THUNDERSTORMS. SO FEW CHANGES MADE BEYOND MONDAY. SCT
&&
.AVIATION...
MVFR CONDITIONS WILL CONTINUE TO BE A POSSIBILITY ACROSS THE AREA
TONIGHT IN THE FORM OF LOW CLOUDS. PATCHY FOG MAY FORM IN A FEW
SPOTS AS WELL. CONDITIONS ARE EXPECTED TO QUICKLY IMPROVE THURSDAY
MORNING WITH A COLD FRONTAL PASSAGE. NORTHWEST WINDS BY THURSDAY
AFTERNOON WILL BE STRONG WITH SUSTAINED SPEEDS OF 20 TO 30 KTS
POSSIBLE. JAMBA
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY FROM 9 AM THURSDAY TO MIDNIGHT MDT THURSDAY
NIGHT FOR FORT PECK LAKE FOR CENTRAL AND SOUTHEAST PHILLIPS...
CENTRAL AND SOUTHERN VALLEY...GARFIELD...MCCONE...PETROLEUM.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS BILLINGS MT
847 PM MDT WED JUL 17 2013
.UPDATE...
MONSOONAL MOISTURE ALONG WITH WEAK LIFT ALOFT IS CONTINUING TO
KEEP THUNDERSTORMS GOING OVER THE WESTERN AND CENTRAL ZONES.
THUNDERSTORM INTENSITY HAS DIMINISHED WITH LOSS OF DAYTIME HEATING
AND SEVERE THUNDERSTORM WATCH 419 HAS BEEN CANCELLED FOR ARE FAR
WESTERN ZONES. HRRR AND SSEO KEEP STORMS MOVING EASTWARD OVERNIGHT
AND HAVE EXTENDED POPS TO FAR SOUTHEASTERN MONTANA AFTER 06Z. HAVE
LOWERED POPS OVER THE WESTERN ZONES THIS EVENING AS MAIN FORCING
SHIFTING INTO EASTERN MONTANA. DRIER AIR WILL BEGIN WORKING INTO
THE REGION FROM THE WEST TONIGHT AS AIR FLOW BECOMING ZONAL. ONLY
MADE SOME MINOR TWEAKS TO THE REST OF THE FORECAST FOR TONIGHT.
RICHMOND
&&
.SHORT TERM...VALID FOR THU AND FRI...
SHORT TERM MODELS DIFFER IN THEIR QPF PROGGS...WHICH IS TYPICAL
FOR A MONSOONAL PATTERN AS MODELS HAVE DIFFICULT TIME HANDLING
SUBTLE FEATURES IN FLOW OVER THE ROCKIES. THUS I WILL USE A MENTAL
BLEND OF MODELS FOR POPS...WEIGHTING THE GFS HIGHEST...AND ALSO
USE SIMPLE TRAJECTORY OF MOMENTUM WHICH WORKS WELL IN MONSOON
FLOW.
FOR TONIGHT...CONVECTION IS EXPECTED TO FIRE FROM ACROSS EASTERN
IDAHO THROUGH SOUTHWEST MONTANA AND INTO CENTRAL WYOMING THIS
AFTERNOON AND SPREAD NORTH AND NORTHEAST. PRECIP WATER IS OVER
1.3 INCHES ACCORDING TO MESOANALYSIS. THIS HAS ME THINKING HEAVY
RAIN AND MAYBE SOME ISOLATED WET MICROBURSTS/OUTFLOWS ARE A
THREAT IN OUR WESTERN ZONES...MAINLY AROUND LIVINGSTON. THE THREAT
OF LARGE HAIL SEEMS BETTER TO ME UP IN NW AND FRONT RANGE SECTIONS
OF MONTANA WHERE FORCING AND HEIGHTS FALLS WILL BE STRONGER. THAT
SAID...SOME STORMS OVER OUR AREA MAY VERY WELL PRODUCE SMALL
HAIL...WITH MAYBE AN ISOLATED CELL WITH QUARTER SIZE. THE
MOMENTUM OF THE MONSOON FLOW WILL LIKELY TAKE CONVECTION OVER INTO
THE CENTRAL ZONES INCLUDING BILLINGS AT MID EVENING AND SLOWLY
DISSIPATE AS IT TRACKS EAST OVERNIGHT.
THURSDAY...FLOW ALOFT FLATTENS OUT AS TROUGH MOVING THROUGH CANADA
TOPPLES OVER THE RIDGE ALOFT. THIS SHUNTS THE MONSOON GENERALLY
SOUTH. THEREFORE...POPS ALONG OUR SOUTHERN BORDERS CONTINUE TO
LOOK GOOD ALONG WITH GENERALLY SEASONAL TEMPERATURES. A DRY AND
GENERALLY WARM STABLE AIR MASS WILL BE OVER OUR REGION ON FRIDAY.
BT
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
LITTLE IN THE WAY OF CHANGES AGAIN TO THE EXTENDED PERIOD
FORECAST. PATTERN CONTINUES TO INDICATE A PERIOD OF DRY AND HOT
WEATHER BEGINNING THIS WEEKEND.
A FLAT UPPER LEVEL RIDGE BUILDS OVER THE REGION BY
SATURDAY...SUPPRESSING MONSOONAL MOISTURE FOR SEVERAL DAYS AND
PUSHING PLAINS MOISTURE TO OUR EAST. TEMPERATURES WILL CLIMB TO
NEAR 100 DEGREES IN MANY AREAS FOR SUNDAY AND MONDAY. MODELS
DIVERGE A BIT MONDAY AS TO STRENGTH OF A SHORTWAVE PUSHING THROUGH
THE REGION THROUGH THE DAY...AND WHAT IS TO FOLLOW. MODELS DO
APPEAR TO FAVOR THE WAVE HAVING LITTLE OR NO PRECIP ASSOCIATED
WITH IT FOR THE CWA...AND MAY ACTUAL AID TEMP RISE MONDAY WITH
ADDITION OF COMPRESSIONAL HEATING.
MODELS REMAIN OUT OF PHASE THROUGH THE REMAINDER OF THE
PERIOD...BUT PATTERN STILL POINTS TOWARD WARM AND DRY CONDITIONS
WHETHER CAUSED BY SIGNIFICANT UPPER LEVEL RIDGE AS IN THE GFS...OR
BY DOWNSLOPE FLOW ASSOCIATED WITH ZONAL FLOW ALOFT. THEREFORE HAVE
CONTINUED WITH GOING WARM TEMPS...LOW TO MID 90S...FOR THE
REMAINDER OF THE PERIOD..AS WELL DRY CONDITIONS ACROSS THE
REGION.
A POINT OF INTEREST WOULD BE REGARDING THE ANOMALOUS LOW
CURRENTLY IN NEW MEXICO. CURRENT PROGS OF THIS SYSTEM POINT TO THE
LOW AND ASSOCIATED MONSOONAL MOISTURE TO IMPACT OUR REGION LATE
WEDNESDAY THROUGH NEXT WEEKEND...JUST AFTER THE END OF THE
OFFICIAL EXTENDED PERIOD. THERE IS STILL A LOT OF
UNCERTAINTY...BUT WORTH KEEPING AN EYE ON.AAG
&&
.AVIATION...
A FEW SHOWERS AND THUNDERSTORMS WITH THE POSSIBILITY OF LOCAL SUB-
VFR CONDITIONS MAY LINGER OVERNIGHT...BUT ACTIVITY SHOULD DECREASE
AS DRYING STARTS TAKING HOLD FROM WEST TO EAST. BY THURSDAY...THAT
WILL LEAD TO WIDESPREAD VFR WEATHER. NORTHWEST WINDS MAY ALSO GUST
TO 25 KT IN SOUTHEASTERN MT ON THURSDAY. SCHULTZ
&&
.PRELIMINARY POINT TEMP/POPS...
THU FRI SAT SUN MON TUE WED
-----------------------------------------------------------
BIL 064/091 061/091 061/092 065/097 065/097 064/092 064/092
31/U 00/U 10/U 00/U 00/U 01/U 11/U
LVM 056/089 052/091 052/095 052/097 052/096 054/093 054/093
41/U 11/U 10/U 00/U 00/U 01/U 11/U
HDN 063/091 059/091 060/094 061/099 062/099 060/094 060/093
31/B 11/U 11/U 10/U 00/U 01/U 11/U
MLS 067/092 061/091 062/093 065/097 066/099 064/093 064/094
22/W 01/U 11/U 11/U 11/U 11/U 11/U
4BQ 061/091 057/089 058/091 061/095 062/097 062/091 061/091
22/W 01/U 11/U 11/U 11/U 11/U 11/U
BHK 063/089 058/084 058/088 061/093 063/095 062/090 061/089
22/W 01/U 11/U 11/U 11/U 11/U 11/U
SHR 060/089 056/090 057/091 057/096 058/096 057/092 057/091
22/T 11/B 11/B 10/U 00/U 01/U 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
323 PM MDT TUE JUL 16 2013
.SHORT TERM...VALID FOR WED AND THU...
STUBBORN POST FRONTAL STRATUS DEVELOPED OVER MUCH OF THE FORECAST
AREA TODAY AIDED BY A DEEP UPSLOPE FLOW...AND BY THE TIME IT
BEGAN THINNING OUT MID LEVEL CLOUDS WERE INVADING THE REGION.
THUS...MOSTLY CLOUDY SKIES LIMITED INSOLATION AND LED TO A BUSTED
FORECAST AT MANY LOCATIONS WITH REGARDS TO SKY AND TEMPERATURES.
SHOWERS WERE SPREADING ACROSS OUR WESTERN MOUNTAINS IN A PUSH OF
MONSOONAL TYPE MOISTURE. ALSO...SOME ELEVATED WEAK THUNDERSTORMS
HAVE DEVELOPED IN ROSEBUD COUNTY. THIS LOOKS RELATED TO A THERMAL
TROUGH AT 500MB. I WILL MENTION LOW POPS IN THE EAST THIS EVENING
AS THIS THERMAL TROUGH FEATURE TRACKS ACROSS...AND EXTEND THE POPS
A BIT SOUTH BASED ON MID LEVEL LAPSE RATES ACROSS THE EASTERN
PLAINS. I ALSO PUSHED POPS IN THE WEST FURTHER EAST FOR THIS
EVENING BASED ON CURRENT SATELLITE AND RADAR IMAGERY. HRRR SEEMS
TO BE PICKING UP THESE TRENDS BEST AND USED IT AS A PROXY FOR
PLACEMENT OF POPS.
FOR WEDNESDAY...THIS SHOULD BE OUR BEST CHANCE OF WIDESPREAD AND
HEAVY PRECIPITATION FOR THE REST OF THE WEEK. A BETTER PUSH OF
MONSOONAL FLOW WILL INVADE FROM THE SOUTH OVER OUR MOUNTAIN
LOCATIONS AND ROTATE A BIT NORTHEAST. HIGH CHANCE TO LOW LIKELY
POPS SEEM GOOD FOR NOW. ONCE WE IDENTIFY A BATCH OF MOISTURE IN
THE SOUTHERLY FLOW WE WILL BE ABLE TO INCREASE POPS AS
APPROPRIATE. DESPITE CLOUD COVER TOMORROW...TEMPERATURES SHOULD BE
BACK AROUND NORMAL AS 850-700 MB TEMPS INCREASE UNDER THE RIDGE.
THURSDAY...OUR RIDGE WILL BE SUPPRESSED AS A LARGE UPPER LOW
TRACKS OVER THE HUDSON BAY REGION. LOOK FOR A FEW THUNDERSTORMS TO
LINGER OVERNIGHT WEDNESDAY INTO THURSDAY AS THEY GRADUALLY MAKE
THEIR WAY EASTWARD. HOWEVER...THE MOISTURE TO THE SOUTH WILL BE
BECOME LARGELY CUT OFF FOR THE TIME BEING. I WILL KEEP THE
HIGHEST POPS IN THE SOUTH AND EAST. TEMPERATURES WILL REMAIN
AROUND NORMAL. BT
.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...
LITTLE IN THE WAY OF CHANGES THROUGH THE EXTENDED PERIOD...WITH
MODELS CONTINUING TO BE IN GOOD AGREEMENT. MAINLY DRY AND HOT
CONDITIONS WILL PREVAIL THROUGH THE EXTENDED PERIOD.
THE EXTENDED FORECAST PERIOD BEGINS FRIDAY AND APPEARS TOP BE THE
COOLEST DAY...WITH BEST POTENTIAL FO PRECIP. AS RIDGE BUILDS JUST
TO THE WEST...MODELS ARE HINTING AT A BACKDOOR COLD FRONT
SLIPPING IN FROM THE NORTHEAST. THE DIFFICULTY IS GAUGING JUST
HOW FAR INTO THE AREA THIS COOL AIR WILL PUSH...IF AT ALL.
CURRENTLY THIS APPEARS TO BE VERY LITTLE WITH ANY IMPACTS PUSHED OFF
TO THE EAST AND NORTHEAST..BUT WILL BARE ATTENTION IN LATER
SHIFTS. MEANWHILE MONSOONAL FLOW WILL CONTINUE FROM THE
SOUTHWEST...BUT IS GREATLY SUPPRESSED BY DEVELOPING RIDGE. SO BEST
CHANCES FOR PRECIP WILL BE IN EXTREME SOUTHERN ZONES...PRIMARILY
HIGH TERRAIN...WITH A VERY SLIGHT CHANCE AROUND KBHK.
FLAT RIDGING BEGINS TO PUSH EASTWARD OVERNIGHT FRIDAY AND
DOMINATES THE PATTERN THROUGH THE REMAINDER OF THE FORECAST
PERIOD. MONSOONAL FLOW WILL SUPPRESSED BY THE RIDGE AND PUSHED OFF
TO THE EAST OF THE AREA. THIS WILL RESULT IN INCREASINGLY DRY AND
HOT CONDITIONS THROUGH THR REMAINDER OF THE FORECAST PERIOD.
TEMPERATURES WILL BE AROUND SEASONAL FOR FRIDAY AND SATURDAY...AND
CLIMB TO MID 90S THROUGH THE REMAINDER OF THE PERIOD...WITH SOME
POTENTIAL FOR REACHING THE CENTURY MARK IN SOME AREAS IF STRONGER
DOWNSLOPE FLOW PANS OUT. AAG
&&
.AVIATION...
STRATUS DECK PERSISTS ACROSS MUCH OF THE CWA...WITH SHOWERS AND
THUNDERSTORMS DEVELOPING...ESPECIALLY IN THOSE AREAS THAT RECEIVED
BETTER HEATING TODAY IN EXTREME NORTHERN ROUTES...AND ALONG THE
HIGH TERRAIN. WIDESPREAD MVFR PERSISTS UNDER LOW STRATUS
CIGS...WITH LOCALIZED IFR VIS POTENTIAL IN HEAVIER PRECIP. 10-20
KNOT NORTHEAST TO EAST WINDS ARE COMMON ACROSS THE REGION TODAY...
WITH GUSTS AS HIGH AS 30 KNOTS POSSIBLE AT KLVM. AAG
&&
.PRELIMINARY POINT TEMP/POPS...
WED THU FRI SAT SUN MON TUE
-----------------------------------------------------------
BIL 062/090 065/092 061/089 064/092 065/096 065/096 064/095
32/T 32/T 21/B 10/B 00/U 01/U 11/U
LVM 059/090 058/091 053/091 052/095 052/097 052/094 054/094
35/T 42/T 21/B 10/B 00/U 01/U 11/B
HDN 062/093 065/093 060/091 059/094 061/098 061/097 060/096
22/T 22/T 21/B 11/B 10/U 01/U 11/U
MLS 063/094 068/094 063/090 065/093 066/096 066/097 064/094
22/T 22/T 11/B 11/B 11/U 11/U 11/U
4BQ 060/094 062/092 059/088 060/091 060/094 061/096 060/092
11/B 12/T 11/B 11/B 11/U 11/U 11/U
BHK 058/091 063/090 059/086 061/089 061/092 062/094 061/091
11/B 12/T 21/U 11/U 12/T 21/U 11/U
SHR 058/091 060/092 057/089 057/091 057/095 057/095 057/095
12/T 22/T 32/T 21/B 10/U 01/U 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
625 PM MDT WED JUL 17 2013
.UPDATE...
DECIDED TO KEEP FFA IN EFFECT FOR ROOSEVELT COUNTY THROUGH TONIGHT
AS RADAR TRENDS SHOW SIGNIFICANT AREA OF LOCALLY HEAVY RAINFALL RE-
DEVELOPING OVER WEST TEXAS LAST COUPLE HOURS. THE 21Z HRRR AND 23Z
RUC SOLUTION ARE IN AGREEMENT ALL CONVECTIVE ACTIVITY WILL BECOME
A MORE WIDESPREAD AREA OF MODERATE TO PERHAPS LOCALLY HEAVY RAIN
OVERNIGHT ALONG AND NEAR THE HIGH TERRAIN OF SOUTH CENTRAL AND
SOUTHEAST NM. FARTHER NORTH AND WEST HAVE LOWERED POPS ACCORDINGLY
AS GUIDANCE AND LATEST SATELLITE TRENDS SHOW LOTS OF CLEARING. SOME
REDEVELOPMENT MAY OCCUR DURING THE PREDAWN HOURS AS IS OFTEN THE
CASE IN MOIST MONSOON FLOW HOWEVER COVERAGE WILL BE VERY LIMITED.
GUYER
&&
.PREV DISCUSSION...612 PM MDT WED JUL 17 2013...
.AVIATION...
00Z TAF CYCLE
AN UPPER LEVEL LOW PRESSURE SYSTEM WILL TRACK SLOWLY SWWD FROM THE
LOWER RIO GRANDE VALLEY THIS EVENING TO NW MEXICO BY THURSDAY
EVENING. THIS TRACK AND PERSISTENT...MOIST...SE LOW LEVEL FLOW ON
THE BACK SIDE OF THE LOW SHOULD FAVOR THE S CENTRAL MTS AND SE
PLAINS FOR SHOWERS AND A FEW THUNDERSTORMS TONIGHT...THEN THE
MOUNTAINS AND AREAS S OF HIGHWAY 60 ON THURSDAY. THE UPSLOPE FLOW
ON THE PLAINS IS EXPECTED TO PRODUCE WIDESPREAD MVFR AND IFR
CONDITIONS IN LOW CLOUDS AND PATCHY FOG ACROSS THE E TONIGHT INTO
THURSDAY MORNING...WITH A RISK OF AIRPORTS ALONG THE E SLOPES OF
THE CENTRAL MT CHAIN...INCLUDING KLVS AND KROW...DROPPING BELOW
AIRPORT MINIMUMS. FLIGHT CATEGORY RESTRICTIONS MAY LINGER INTO THE
EARLY AFTN THURSDAY ALONG AND E OF THE S CENTRAL MTS.
44
.PREV DISCUSSION...257 PM MDT WED JUL 17 2013...
THE LATEST WATER VAPOR SATELLITE IMAGERY SHOWS THE UPPER LOW
PROGRESSING SOUTHWEST ACROSS THE RIO GRANDE NEAR T-OR-C...WITH DRY
AIR WRAPPING INTO THE WEST SIDE OF THE CIRCULATION AND A VERY
MOIST ATMOSPHERE ON THE EAST SIDE. AREA 12Z UPPER AIR SOUNDINGS
CONFIRMED THIS...WITH BOTH KAMA AND KMAF SHOWING PWATS AROUND 1.5
INCHES AND ONLY 0.92 HERE AT KABQ (STILL SLIGHTLY ABOVE NORMAL).
12Z MODEL TIME SERIES FOR KABQ SHOWS PWAT INCREASING TO BETWEEN
1.1 AND 1.3 INCHES OVERNIGHT AND STAYING THERE THROUGH THE
WEEKEND. THIS INCREASE IN MOISTURE COMBINED WITH INCREASING TEMPS
EACH DAY SHOULD BRING BETTER CHANCES FOR RAIN TO THE ABQ METRO
FROM FRIDAY INTO THE WEEKEND.
FURTHER SOUTH...A FLASH FLOOD WATCH REMAINS IN EFFECT FOR MUCH OF
SOUTHEAST AND SOUTH CENTRAL PORTIONS OF THE STATE. WE`RE EXTENDING
OUR FLASH FLOOD WATCH FOR LINCOLN AND CHAVES COUNTY THROUGH
THURSDAY MORNING...BUT DROPPING ROOSEVELT AS THE FOCUS SHIFTS TO
THE FAVORED UPSLOPE AREAS OF THE SOUTH CENTRAL MOUNTAINS...
INCLUDING THE LITTLE BEAR BURN SCAR AND SOUTHWEST CHAVES COUNTY.
THE THREAT ON THURSDAY MAY PERSIST OVER THE SOUTH CENTRAL
MOUNTAINS AND WILL DEFINITELY PICK-UP OVER CATRON COUNTY AND THE
WHITEWATER-BALDY BURN SCAR. HIGH POP...HIGH PWAT SCENARIO WITH
UPSLOPE TO BOOT...BUT NOT THE BEST SURFACE BASED INSTABILITY
GIVEN EXTENSIVE CLOUD COVER FORECAST THURSDAY. STORM MOTION WILL
DECREASE SIGNIFICANTLY ON THURSDAY ACROSS NORTHERN PORTIONS OF THE
FORECAST AREA AS THE LOW PULLS FURTHER AWAY...SO ANY STORMS THAT
FORM OVER THE NORTH WILL BE MOVING SLOWER. HOWEVER...THE WARM-UP
ON THURSDAY WILL NOT BE SIGNIFICANT ENOUGH TO PRODUCE DEEPER
CONVECTION. THIS ALL CHANGES BY FRIDAY AS THE UPPER LOW WILL BE
OVER NORTHERN MEXICO AND STORM MOTION WILL BE EVEN LIGHTER ACROSS
THE NORTHERN MOUNTAINS. MORE WARMING ON FRIDAY WILL INCREASE
SURFACE BASED INSTABILITY WHILE PWATS REMAIN ABOVE TO WELL ABOVE
NORMAL. THIS ADDS-UP TO A LOCALLY HEAVY RAINFALL THREAT FRIDAY...
WITH PARTICULAR CONCERN FOR NORTHERN BURN SCARS. LOOK FOR A REPEAT
ON SATURDAY...WITH STORM MOTION NEAR ZERO FOR THE NORTHERN
MOUNTAINS.
LOOK FOR A CONVECTIVE DOWNTREND EARLY NEXT WEEK AS THE UPPER HIGH
OVER NEVADA MOVES EAST OR SOUTHEAST TO OVER CO/NM BY WEDNESDAY.
THE CONVECTIVE DOWNTREND DUE TO DECREASING MOISTURE AND INCREASING
PRESSURE HEIGHTS UNDER THE INFLUENCE OF A 595DAM 500MB HIGH.
TEMPERATURES ARE FORECAST TO BE BACK ABOVE NORMAL AREA-WIDE BY
TUESDAY AND STAY THERE FOR AWHILE.
11
.FIRE WEATHER...
LATEST IR IMAGERY INDICATES THAT THE UPPER LOW IS POSITIONED NEAR
SOCORRO...AND WILL CONTINUE TO SLIDE TOWARDS FAR SOUTHWEST NEW
MEXICO THIS EVENING. SHOWERS WILL CONTINUE ACROSS SOUTHEAST PORTIONS
OF THE STATE THROUGH THE REST OF THE DAY...AND BECOME MORE
CONVECTIVE WITH DAYTIME HEATING. THE FOCUS FOR THE HEAVIEST RAINS
WILL BE OVER THE SACRAMENTO MOUNTAINS AND COULD IMPACT BURN SCARS IN
THAT AREA. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL
ALSO BE POSSIBLE PRIMARILY OVER THE NORTHERN AND SOUTHWEST
MOUNTAINS. EAST WINDS AT 20 TO 30 MPH WITH GUSTS TO 40 MPH WILL
RETURN LATE THIS EVENING FOR THE ABQ METRO DUE TO A STRENGTHENED
PRESSURE GRADIENT. LITTLE CHANGE IN OVERNIGHT RH RECOVERIES IS
EXPECTED AND ANOTHER ROUND OF LOW CLOUDS AND PATCHY FOG WILL BE
POSSIBLE ACROSS THE EASTERN PLAINS.
THE UPPER LOW WILL CONTINUE TO WEAKEN AS IT MOVES OVER NORTHWEST
MEXICO THURSDAY. THE MAIN MOISTURE PLUME WILL BE FOCUSED OVER THE
SOUTHWEST MOUNTAINS...THOUGH SHOWER AND THUNDERSTORM ACTIVITY WILL
REMAIN POSSIBLE ACROSS MUCH OF THE STATE WITH DIURNAL HEATING.
TEMPERATURES WILL REMAIN BELOW NORMAL FOR MOST OF THE STATE...THOUGH
A 5 TO 10 DEGREE WARM-UP FROM WEDNESDAYS HIGHS IS EXPECTED.
LITTLE CHANGE IN OVERALL PATTERN FRIDAY AND INTO THE WEEKEND AS THE
UPPER LOW CONTINUES ITS SLOW TREK WEST WITH HIGH PRESSURE TO THE
NORTH SLOWLY BUILDING BACK OVER THE STATE. DIURNAL CONVECTION EACH
DAY WILL BE FOCUSED OVER WESTERN AND CENTRAL NEW MEXICO AND FAVOR
THE HIGH TERRAIN. A SLIGHT DRYING TREND THROUGH THIS PERIOD IS
EXPECTED...THOUGH OVERNIGHT RH RECOVERIES WILL REMAIN GOOD ALL AREAS
EXCEPT VALLEY LOCATIONS WHERE RECOVERIES WILL BECOME FAIR.
TEMPERATURES WILL TREND UP...REACHING NEAR NORMAL VALUES FOR THE
NORTHERN AND CENTRAL NEW MEXICO BY MONDAY. POCKETS OF FAIR TO POOR
VENTILATION RATES WILL BE POSSIBLE EACH DAY...MAINLY ACROSS
NORTHWEST NEW MEXICO.
THE GFS AND ECMWF SHOW SOMEWHAT SIMILAR DEPICTIONS FOR EARLY NEXT
WEEK. HIGH PRESSURE WILL BUILD OVER THE GREAT BASIN AND STRETCH OVER
THE STATE...RESULTING SHOWER AND THUNDERSTORM ACTIVITY ALONG THE
NM/AZ BORDER. THE PROGRESSION OF THIS HIGH PRESSURE EAST THROUGH THE
WEEK IS DEPICTED DIFFERENTLY...BUT A DECREASE IN SHOWER AND
THUNDERSTORM COVERAGE WILL BE POSSIBLE.
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 6 AM MDT THURSDAY FOR THE FOLLOWING ZONES...
NMZ526-536-538>540.
&&
$$
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
729 PM EDT WED JUL 17 2013
.SYNOPSIS...
AN ACTIVE WEATHER PATTERN WILL CONTINUE ACROSS THE NORTH COUNTRY
WITH DAILY CHANCES FOR SCATTERED SHOWERS AND THUNDERSTORMS THROUGH
SATURDAY. SOME STORMS COULD BE STRONG TO SEVERE THROUGH THE PERIOD.
IN ADDITION...THE HOT AND HUMID WEATHER WILL CONTINUE UNTIL
SATURDAY...BEFORE MUCH DRIER AND COOLER AIR ARRIVES ON SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 729 PM EDT WEDNESDAY...MINOR UPDATES TO FORECAST TO ADJUST
TEMPS/CLDS. FIRST ROUND OF RW/TRW MVG THRU THE CWA ATTM...THE BULK
OF WHICH EXITING THRU THE NC NE VT REGION. THIS WILL PAVE WAY FOR
THE SECOND LINE OF RW/TRW CURRENTLY ACROSS SOUTHERN QUEBEC/SE
ONTARIO AND SHOULD BEGIN TO AFFECT THE CWA OVER THE NEXT COUPLE
HRS. WITH THIS FRNT APPROACHING HAVE LEFT CURRENT POPS/WX AS IS
FOR NOW. SEVERE THUNDERSTORM WATCH #416 REMAINS IN EFFECT.
PREVIOUS DISCUSSION...SVR WATCH #416 CONTINUES UNTIL MIDNIGHT FOR
ENTIRE CWA. EXPECTING SEVERAL ROUNDS OF STORMS...FIRST ACRS THE
SLV/OTTAWA VALLEY AND NORTHERN NY BTWN 4PM AND 6PM...THEN
SECONDARY AND MORE POTENT LINE OF STORMS APPROACHES NORTHERN ZNS
BTWN 22-00Z THIS EVENING. THIS WL HAVE POTENTIAL FOR A WELL
ORGANIZED LINE OF STORMS WITH ENHANCED BOWING SEGMENTS POSSIBLE.
STILL THINKING THE PRIMARY THREAT WL BE STRONG/DAMAGING
WINDS...WITH ISOLATED/SCATTERED POWER OUTAGES/TREES DOWN. THINKING
LINE WL ENTER CPV BTWN 01-02Z...AND DISSIPATE BY 03Z ACRS OUR
EASTERN CWA. THE MAIN CONCENTRATION WL BE ACRS NORTHERN NY INTO
CENTRAL/NORTHERN VT.
FCST CHALLENGE WL BE TIMING OF THE CONVECTION WEAKENING/MOVING EAST
OF OUR CWA LATE THIS EVENING...FOLLOWED BY FOG POTENTIAL OVERNIGHT.
WATER VAPOR SHOWS POTENT S/W ENERGY ENTERING THE OTTAWA VALLEY
ATTM...WHICH WL CONT TO DEVELOP A LINE OF SVR STORMS ACRS OUR
CENTRAL/NORTHERN CWA THIS EVENING. THIS SYSTEM IS PROGGED TO BE EAST
OF CWA BY 06Z TONIGHT...WHICH COMBINED WITH LOSS OF DAYTIME
HEATING/INSTABILITY WL RESULT IN A DECREASE IN SHOWERS/STORMS. WL
MENTION CHC/LIKELY POPS THRU 03Z...ALONG WITH ENHANCED WORDING FOR
WINDS/HEAVY RAINFALL. RAP 13 SHOWS DEEP LAYER SHEAR VALUES BTWN 35
AND 40 KNOTS ACRS OUR NORTHERN CWA...ALONG WITH SFC BASED CAPE
AROUND 2000 J/KG...PERSISTING THRU THE EVENING HRS. THIS WL PROVIDE
ENOUGH INSTABILITY TO KEEP STORMS STRONG/SVR INTO THE EVENING
HOURS...WITH PRIMARY THREAT BEING DAMAGING WINDS. GIVEN...VERY WARM
DWPTS AND SOUTHERLY WINDS...EXPECT LOWS MAINLY IN THE M60S MTNS TO
L70S WARMER VALLEYS WITH PATCHY FOG POSSIBLE.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
AS OF 340 PM EDT WEDNESDAY...THE FCST CHALLENGE WL BE AREAL COVERAGE/
INTENSITY OF STORMS EACH AFTN/EVENING THRU FRI NIGHT.
OVERALL...EXPECTING AN ACTIVE COUPLE DAYS WITH SEVERAL ROUNDS OF
STRONG TO POSSIBLY SEVERE STORMS...ALONG WITH VERY HOT AND HUMID
CONDITIONS...PERSISTING THRU FRIDAY.
THURS INTO THURS NIGHT...A LITTLE MORE UNCERTAINTY ON PLACEMENT OF
ULVL SUPPORT...POSITION OF DEEPEST MOISTURE...AND ASSOCIATED SFC
BOUNDARY...ESPECIALLY GIVEN THIS EVENINGS CONVECTION. LATEST 12Z
GFS SHOWS BETTER DYNAMICS AND RH FIELDS...ALONG WITH THE
ASSOCIATED CONVECTION ACRS OUR SOUTHERN CWA...WHILE NAM12 SHOWS
POTENT 5H ENERGY AND GOOD RH ENTERING THE SLV BY 18Z AND MOVING INTO
THE CPV BY 21Z...AND THRU VT BY 03Z FRIDAY. BOTH NAM/GFS SHOW
FAVORABLE SHEAR/INSTABILITY PARAMETERS FOR ORGANIZED
CONVECTION...ALONG WITH A LEFTOVER SFC BOUNDARY/TRRN FOR LLVL
TRIGGER...BUT ULVL SUPPORT IS WEAKER. SOUNDING PROFILES SHOW CAPE
VALUES BTWN 2000 AND 2500 J/KG AND BEST 0 TO 6KM SHEAR OF 40 NEAR
NEAR THE INTERNATIONAL BORDER...CLOSEST TO THE MID LVL WIND MAX.
ONCE AGAIN...PRIMARY SVR WEATHER THREAT WL BE ISOLATED PULSE STRONG
AND DAMAGING WINDS. IN ADDITION...LOCAL 2KM AND 4KM ARE VERY ROBUST
WITH DEVELOPMENT OF COMPOSITE REFLECTIVITY FIELDS...BUT MAYBE A BIT
OVERDONE ON AREAL COVERAGE...BASED ON PREVIOUS EXPERIENCE. WL CONT
TO MENTION CHC POPS FROM 16Z THRU 03Z...THINKING ACTIVITY WL START
EARLIER ON THURS...BASED ON POSITION OF S/W ENERGY AND DISSIPATE BY
EARLY EVENING. PROGGED 85H AND 925MB TEMPS COOLER SLIGHTLY AND
SUPPORT HIGHS IN THE M80S MTNS TO L90S WARMER VALLEY
LOCATIONS...WITH VERY SIMILAR OVERNIGHT LOWS TO RECENT NIGHTS...M60S
TO L70S.
ON FRIDAY...MID/UPPER LVL TROF ACRS THE GREAT LAKES APPROACHES OUR
WESTERN CWA...ALONG WITH SEVERAL EMBEDDED S/W`S IN THE FAST
WEST/SOUTHWEST FLW ALOFT. THIS ENERGY/HGHT FALLS...COMBINED WITH
BETTER 850 TO 500MB RH PROFILES WL RESULT IN MORE AFTN/EVENING
SHOWERS/STORMS ON FRIDAY. NAM/GFS CONT TO SHOW BEST 0 TO 6 KM SHEAR
VALUES BTWN 40 AND 45 KNOTS ACRS OUR CENTRAL/NORTHERN CWA...ALONG
WITH CAPE VALUES AROUND 2000 J/KG. SO A FEW STRONG/SVR STORMS WL BE
POSSIBLE. SOME UNCERTAINTY ON OVERALL ORGANIZATION AND TIMING OF
INDIVIDUAL S/W`S IN FAST FLW ALOFT...ALONG WITH PLACEMENT OF
PRE-FRONTAL TROFS. SPC DAY 3 HIGHLIGHTS OUR CENTRAL/NORTHERN CWA IN
SLIGHT RISK. PWS BTWN 1.50 AND 2.0" SUPPORTS THE POTENTIAL FOR HEAVY
RAINFALL...BUT WITH STORM MOTION OF 20 TO 30 KNTS...NOT ANTICIPATING
ANY SIGNIFICANT HYDRO PROBLEMS. MAYBE SOME MINOR POOR DRAINAGE/URBAN
TYPE STUFF. PROGGED 85H TEMPS BTWN 16-18C AND 925MB TEMPS BTWN
22-24C...SUPPORT HIGHS ONCE AGAIN WELL INTO THE M/U 80S MTNS TO M90S
WARMER VALLEY LOCATIONS...ESPECIALLY SW DOWNSLOPE AREAS LIKE PBG.
HEAT INDEX VALUES WL ONCE AGAIN APPROACH 100 DEGREES IN A FEW
LOCATIONS.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 310 PM EDT WEDNESDAY...COLD FRONT EXPECTED TO OPEN THE
EXTENDED PORTION OF THE FORECAST NEAR THE SAINT LAWRENCE VALLEY.
DUE TO THE UPPER-LEVEL GEOSTROPHIC FLOW ROUGHLY PARALLEL TO THE
ORIENTATION OF THE SFC FRONT...HAVE OPTED TO SLOW THE APPROACHING
COLD FRONT`S PROGRESSION THROUGH THE NORTH COUNTRY. THUS HAVE
MAINTAINED HIGH CHANCE TO LIKELY POPS ON SATURDAY...GRADUALLY
TAPERING TO SLIGHT CHANCE/CHANCE ON SATURDAY NIGHT. NOT QUITE THE
DEGREE OF INSTABILITY AS EXPECTED ON FRIDAY BUT PWATS STILL IN THE
1.5-2.0" RANGE SUGGEST THAT ANY STORMS COULD PRODUCE SOME LOCALLY
HEAVY RAIN. WENT WITH HIGHS IN THE UPPER 70S TO LOW/MID 80S BASED
ON EXPECTED CLOUD COVER AND PRE-FRONTAL 925 MB TEMPERATURES AROUND
18-21C...WENT WITH HIGHS IN THE UPPER 70S TO MID-80S.
A NOTICEABLY COOLER AND DRIER SUNDAY AND MONDAY IS EXPECTED AS
BROAD CANADIAN HIGH PRESSURE SETTLES INTO THE REGION. TEMPERATURES
RETURN CLOSER TO NORMAL/BELOW NORMAL FOR MID JULY. GIVEN ONGOING
ACTIVE WEATHER I DIDN`T LOOK TOO CLOSELY INTO NEXT WEEK...THOUGH IT
DOES APPEAR TO TURN MORE ACTIVE WEATHER-WISE WITH TEMPERATURES AND
HUMIDITY LEVELS BEGINNING TO REBOUND. THERFORE HAVE KEPT A TOKEN
SLIGHT CHANCE/CHANCE POPS GOING.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
THROUGH 00Z FRIDAY...THRU 06Z-08Z...VFR COND WILL TRANSFER DOWN TO
MVFR/IFR AT TIMES FROM RW/TRW PUSHING THRU AREA. VSBY 3-6SM AND
CEILINGS BKN035-050. FG DEVELOPS FROM W TO E THAT WILL FURHTER
BRING DOWN VSBY FOR SLK/MPV...WHERE 1-3SM DEVLEOPS AND CARRIES
THRU 13Z. VFR AFT 13Z THURSDAY ALL SITES. WINDS SSW 5-15KTS BECM
LGT/VAR IN SPOTS AFT FROPA...THEN BECM WSW 5-10KTS FROM 13Z-14Z
THURSDAY ONWARD.
OUTLOOK 00Z FRIDAY THROUGH MONDAY...
00Z FRIDAY THROUGH SATURDAY...MAINLY VFR CONDITIONS EXPECTED DURING
THE DAY WITH ISOLATED PATCHY FG/BR OVERNIGHT...MAINLY AT
KSLK/KMPV. SCATTERED AFTERNOOON SHOWERS/THUNDERSTORMS EACH DAY
THROUGH THE PERIOD WHICH MAY BRING BRIEF PERIODS OF MVFR/IFR
VISIBILITIES.
SUNDAY AND MONDAY...VFR UNDER BUILDING HIGH PRESSURE.
&&
.MARINE...
AS OF 310 PM EDT WEDNESDAY...STRONG THUNDERSTORMS WILL LIKELY
AFFECT THE LAKE CHAMPLAIN WATERS LATER THIS AFTERNOON AND EVENING.
A LAKE THUNDERSTORM ADVISORY IS IN EFFECT UNTIL FURTHER NOTICE.
WATCHING TWO LINES OF STRONG THUNDERSTORMS NOW OVER NORTHERN AND
EASTERN ONTARIO WHICH WILL SLIDE SOUTHEASTWARD ACROSS LAKE
CHAMPLAIN TONIGHT...WITH ADDITIONAL DEVELOPMENT POSSIBLE AHEAD OF
THE LINES OF ONGOING STORMS. STORMS WILL BE CAPABLE OF GUSTY TO
LOCALLY DAMAGING WINDS...ROUGH WAVES...AND CLOUD TO GROUND
LIGHTNING.
&&
.CLIMATE...
MAX TEMP RECORDS TODAY THROUGH FRIDAY. BEST SHOT TODAY AT
KMSS...THEN ON FRIDAY AT KMPV AND KMSS. SHORTER PERIOD OF RECORD AT
THESE SITES THAN AT K1V4 AND KBTV.
07/17/2013 07/18/2013 07/19/2013
KBTV 97/1999 99/1953 98/1942
KMPV 93/1982 96/1953 92/1991
K1V4 94/1953 99/1953 95/1991
KMSS 92/2012 95/1953 93/1991
&&
.EQUIPMENT...
WE CONTINUE TO EXPERIENCE LOSS OF SIGNAL/POWER WITH THE KTYX
RADAR...ALONG WITH IT GOING IN AND OUT OF SERVICE. TECHS HAVE BEEN
AT THE SITE LOOKING INTO THE PROBLEM AND HAVE OPENED A TICKET WITH
THE RADAR OPERATION CENTER. BOTTOM LINE EXPECT VERY LIMITED DATA
FROM THE KTYX RADAR.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...TABER
NEAR TERM...JN/TABER
SHORT TERM...TABER
LONG TERM...LOCONTO
AVIATION...JN/LOCONTO
MARINE...BTV
CLIMATE...BTV
EQUIPMENT...BTV
AREA FORECAST DISCUSSION...CORRECTED
NWS BINGHAMTON NY
301 PM EDT TUE JUL 16 2013
.SYNOPSIS...
A LARGE AREA OF HIGH PRESSURE OVER THE OHIO VALLEY WITH VERY WARM
AND HUMID AIR WILL INFLUENCE OUR WEATHER THROUGH FRIDAY. A COLD
FRONT WILL DROP SOUTH OF THE REGION SATURDAY WITH A CHANCE FOR
STRONG THUNDERSTORMS. AFTER THIS FRONT PASSES BY...COOLER AND LESS
HUMID AIR WILL COVER THE REGION FOR EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
SCT CUMULUS IN CLOUD STREETS COVER MUCH OF THE CWA AS THE LL FLOW
IS NWRLY. DEWPOINTS WERE A BIT LOWER THIS AFTERNOON THAN YSTA
RUNNING IN THE MID TO UPPER 60S. RAP MODEL SOUNDINGS SHOW A
CAPPING INVERSION NR 800 MB WHICH WAS KEEPING DEEP CONVECTION IN
CHECK HENCE DON/T EXPECT ANY SHRA OR TSRA FOR THE REST OF TODAY OR
THIS EVENING.
FOR OVERNIGHT...EXPECT MORE VALLEY FOG SIMILAR TO THIS MORNING IN
OUR RIVER VALLEYS.
FOR WEDNESDAY...W-NW LL FLOW WILL ADVECT SLIGHTLY HIGHER DEWPOINTS
INTO C NY AND NE PA AS PER MODEL GUIDC. NAM AND GFS BOTH SHOW
HIGHER DEWPOINTS AT 850 MB COMING SOUTHEASTWARD BY WED WHICH SHUD
MIX DOWN WITH BNDRY LAYER GROWTH FROM INSOLATION. MODEL GUIDC
SUGGESTS DEWPOINTS IN THE LOWER 70S ALONG THE LAKE ONTARIO PLAIN
AND UPPER 60S REST OF CWA. HIGH TEMPERATURES ALREADY SHUD BE IN
THE LOW 90S TODAY IN SYR AND WUD EXPECT THE SAME FOR WED. HENCE
HEAT INDICES WED PM WILL BE CLOSE TO 100F IN THE SYR-AUBURN AREAS
WHICH IS OUR HEAT ADVY CRITERIA. SO ISSUED HEAT ADVY FOR A FEW
COUNTIES ALONG THE LAKE ONTARIO PLAIN INCLUDING SYR TO COVER.
ANOTHER CONCERN FOR WED WILL BE MORE INSTABILITY WITH A BIT HIGHER
DEWPOINTS. MODEL SOUNDINGS ALL SHOW CAPES BETWEEN 1500 J/KG AND
2000 J/KG BY WED PM. FORCING WILL BE WEAK BUT WITH A LL NW FLO
SEE SOME ISLD SHRA/TSRA FORMING FROM MTN VALLY CRLCNS AND LAKE
BOUNDARIES. SO WENT WITH SLGHT CHC TSRA IN MUCH OF CNTRL NY.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
FOR THURSDAY...SHORT WAVE TRACKING ACROSS SWRN AND SC CANADA WILL
REACH SERN CANADA BY THURSDAY PM...THIS WILL TURN THE MID TO UPPER
LVL FLOW MORE NWRLY AND PRESS A FRNT DOWN TO NRN NEW ENGLAND AND THE
UPPER LAKES. AT 500 MB THE TEMPERATURES BEGIN TO FALL FROM WEAK
CAA AS WELL FROM THE NW FLOW. AT LL/S THE DEWPOINTS AGAIN WILL BE
WITHIN A FEW DEGREES OF 70F. SO THINK THERE WILL BE SCT TSRA IN
NC NY TO ISLD CONVECTION FARTHER S TO NE PA AS CAPES ARE RUNNING
BETWEEN 1000 AND 1500 J/KG AND LL FLOW AGAIN RUNS UP INTO THE
HILLS OF NY AND NRN PA.
FOR FRIDAY...LONGER WAVELENGTH UPPER LEVEL FEATURE OVER SC CANADA
TO THE UPR MIDWEST WILL TURN THE LL FLOW MORE SWRLY AND ADVECT
SOMEWHAT HIGHER LL MOISTURE INTO NY AND PA AND INCREASE
INSTABILITY. CAPES CUD EXCEED 2000 J/KG. 0-6 KM BULK SHEAR WILL
ALSO BE BETWEEN 30 AND 40 KNOTS BY AFTERNOON. POTENTIAL IS FOR
SOME CONVECTION WELL IN ADVANCE OF THE FRONT. THE REGION WILL FALL
UNDER THE RIGHT ENTRANCE REGION OF A STRG UPPER LEVEL JET IN SERN
CANADA BY FRI PM TO ENHANCE UPPER DVRG. AT LL/S THERE IS A 30-35
KNOT W-SW LLJ RUNNING FROM THE LOWER LAKES TO NRN NY STATE. THIS
IS FAVORABLE TO SUPPORT STRG TO SVR CONVECTION ACRS NC NY WHERE
POPS WILL BE HIGHEST. WILL TAPER DOWN POPS SOME INTO NE PA FRI.
BOTH THURSDAY AND FRIDAY...HEAT INDICES WILL BE CLOSE TO 100F IN
NE PA AND SRN SULLIVAN CO NY AND POSSIBLY SC NY. THE LAKE ONTARIO
PLAIN LIKELY WILL REMAIN CLOSE TO 100F HEAT INDICES BOTH DAYS. FOR
NOW WILL COVER IN HWO...BUT MAY HAVE TO EXTEND HEAT ADVISORIES UP
THERE AND EXPAND HEAT ADVISORIES FARTHER S AND E.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
LTL CHG TO THE MED RNG FCST WHICH FEATURES THE PSSG OF A CANADIAN
CDFNT ON SAT...FOLLOWED BY MUCH MORE COMFORTABLE CONDITIONS. BEST
CHCS FOR TSRA APPEAR TO BE OVER NRN SXNS ON FRI NGT...SPREADING
INTO CNTRL NY AND NE PA ON SAT. POTNL FOR STRONG/SVR TSRA ON SAT GIVEN
THE MDL FCST WIND FIELDS AND INSTABILITY...WITH TIMING OF FNT
LOOKING QUITE FVRBL FOR SRN/CNTRL NY AND NE PA ON SAT. XPCT
LINGERING ACTIVITY TO PUSH OFF TO THE SE ON SAT NGT...WITH FAIR WX
AND MORE SEASONABLE TEMPS RETURNING ON SUNDAY. EARLY NXT WEEK
LOOKING FABULOUS WITH MAXES 75-80 AND LOWS INTO THE 50S...AND MUCH
LOWER HUMIDITY.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
HI PRES SFC AND ALOFT WITH VFR PREVAILING THRU 18Z WED. XPCT SCT
4-5 KFT CU DURING DAY...AND MAINLY SKC TNGT. ONLY EXCEPTION TO VFR
WILL BE VLY FOG/STRATUS LATE TNGT AFFECTING ELM IN THE 07-13Z
TIME FRAME. WINDS THIS AFTN NW TO NRLY 10 KTS...L&V TNGT...THEN
WRLY ON WED 10 KTS.
.OUTLOOK...
WED NGT/THU/FRI...VFR PREVAILS. CHANCE FOR LATE NGT/EARLY MRNG MVFR/IFR
FG/BR/HZ AT KELM. ISOLD OR WDLY SCT AFTN TSRA MAY ALSO PRODUCE
BRIEF RESTRICTIONS.
FRI NGT INTO SAT...MVFR IN TSRA...MOST NUMEROUS OVER NRN SITES FRI
NGT...AND AREA WIDE ON SAT.
SAT NGT...MVFR PSBL AT AVP IN SHRA/TSRA EARLY....IMPRVG TO VFR CNTRL
NY.
SUN...VFR.
&&
.CLIMATE...
BELOW ARE THE RECORD HIGHS FOR THE NEXT FEW DAYS AT OUR MAIN AIRPORTS
AND OUR FORECAST HIGHS. HIGH TEMPERATURES SHOULD FALL SHORT OF THE DAILY
RECORDS...
SYRACUSE HANCOCK FIELD...
TODAY 97 SET IN 1988. FORECAST 92
WEDNESDAY 101 SET IN 2012. FORECAST 92
THURSDAY 97 SET IN 1953. FORECAST 91
GREATER BINGHAMTON AIRPORT...
TODAY 98 SET IN 1988. TODAY`S FORECAST 88
WEDNESDAY 91 SET IN 1991. FORECAST 88
THURSDAY 93 SET IN 1953. FORECAST 88
SCRANTON/WILKES-BARRE INTERNATIONAL AIRPORT...
TODAY 101 SET IN 1988. TODAY`S FORECAST 91
WEDNESDAY 96 SET IN 1999. FORECAST 93
THURSDAY 98 SET IN 1953. FORECAST 93
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...HEAT ADVISORY FROM NOON TO 8 PM EDT WEDNESDAY FOR NYZ016>018.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...DJN
LONG TERM...
AVIATION...
CLIMATE...
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
213 PM EDT TUE JUL 16 2013
.SYNOPSIS...
A LARGE AREA OF HIGH PRESSURE OVER THE OHIO VALLEY WITH VERY WARM
AND HUMID AIR WILL INFLUENCE OUR WEATHER THROUGH FRIDAY. A COLD
FRONT WILL DROP SOUTH OF THE REGION SATURDAY WITH A CHANCE FOR
STRONG THUNDERSTORMS. AFTER THIS FRONT PASSES BY...COOLER AND LESS
HUMID AIR WILL COVER THE REGION FOR EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
SCT CUMULUS IN CLOUD STREETS COVER MUCH OF THE CWA AS THE LL FLOW
IS NWRLY. DEWPOINTS WERE A BIT LOWER THIS AFTERNOON THAN YSTA
RUNNING IN THE MID TO UPPER 60S. RAP MODEL SOUNDINGS SHOW A
CAPPING INVERSION NR 800 MB WHICH WAS KEEPING DEEP CONVECTION IN
CHECK HENCE DON/T EXPECT ANY SHRA OR TSRA FOR THE REST OF TODAY OR
THIS EVENING.
FOR OVERNIGHT...EXPECT MORE VALLEY FOG SIMILAR TO THIS MORNING IN
OUR RIVER VALLEYS.
FOR WEDNESDAY...W-NW LL FLOW WILL ADVECT SLIGHTLY HIGHER DEWPOINTS
INTO C NY AND NE PA AS PER MODEL GUIDC. NAM AND GFS BOTH SHOW
HIGHER DEWPOINTS AT 850 MB COMING SOUTHEASTWARD BY WED WHICH SHUD
MIX DOWN WITH BNDRY LAYER GROWTH FROM INSOLATION. MODEL GUIDC
SUGGESTS DEWPOINTS IN THE LOWER 70S ALONG THE LAKE ONTARIO PLAIN
AND UPPER 60S REST OF CWA. HIGH TEMPERATURES ALREADY SHUD BE IN
THE LOW 90S TODAY IN SYR AND WUD EXPECT THE SAME FOR WED. HENCE
HEAT INDICES WED PM WILL BE CLOSE TO 100F IN THE SYR-AUBURN AREAS
WHICH IS OUR HEAT ADVY CRITERIA. SO ISSUED HEAT ADVY FOR A FEW
COUNTIES ALONG THE LAKE ONTARIO PLAIN INCLUDING SYR TO COVER.
ANOTHER CONCERN FOR WED WILL BE MORE INSTABILITY WITH A BIT HIGHER
DEWPOINTS. MODEL SOUNDINGS ALL SHOW CAPES BETWEEN 1500 J/KG AND
2000 J/KG BY WED PM. FORCING WILL BE WEAK BUT WITH A LL NW FLO
SEE SOME ISLD SHRA/TSRA FORMING FROM MTN VALLY CRLCNS AND LAKE
BOUNDARIES. SO WENT WITH SLGHT CHC TSRA IN MUCH OF CNTRL NY.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
4 AM UPDATE...
CONTINUED HOT PERIOD WILL FEATURE GRADUAL FLATTENING OF LARGE
UPPER HIGH...AS WESTERLIES START TO CREEP ACROSS THE INTERNATIONAL
BORDER. MAIN CONCERN WILL BE FOR HIGH HEAT INDICES ECLIPSING HEAT
ADVISORY CRITERIA /100 DEGREES/ AT LOWER ELEVATIONS
WEDNESDAY...AND PERHAPS AGAIN THURSDAY AT LEAST IN THE SOUTHERN
ZONES. THIS WILL BE A RESULT OF DEWPOINTS EDGING BACK INTO THE
UPPER 60S/LOW 70S WHILE AS HIGHS STILL MANAGE UPPER 80S TO MID
90S. HEAT ADVISORIES WILL LIKELY BE NEEDED FOR AT LEAST LAKE PLAIN
AND WYOMING/DELAWARE VALLEYS IF NOT EVEN A BIGGER CHUNK OF THE
CWA WEDNESDAY...AND PERHAPS AGAIN FOR AT LEAST WYOMING/DELAWARE
VALLEYS THURSDAY. AS MENTIONED IN NEAR TERM DISCUSSION
THOUGH...REGARDLESS OF WHETHER OR NOT TECHNICALLY MEETING
CRITERIA...HEAT-RELATED PRECAUTIONS SHOULD BE EXERCISED.
AS FAR AS CONVECTION GOES...WITH FLATTENING OF THE RIDGE AND THUS
LOWERING OF 500MB HEIGHTS...CAP WILL BE WEAKENED AND THUS THE
CHANCE OF THUNDERSTORMS WILL FINALLY BE REINTRODUCED TO THE
FORECAST. ONLY OUTER PERIPHERY OF WESTERLIES AND TRAILING EDGES OF
EMBEDDED WAVES WILL BE SKIMMING INTO THE AREA...SO ONLY SLIGHT
CHANCE OF THUNDERSTORMS FIGURED FOR NORTHERN ZONES
WEDNESDAY...THEN AT LEAST LOW CHANCE RANGE ACROSS MOST THE AREA
THURSDAY /HIGHEST AGAIN NORTH/. THE BETTER...AND STRONGER...CONVECTION
THREATS WILL BE TOWARDS THE WEEKEND AS DISCUSSED IN THE LONG TERM
PORTION.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
LTL CHG TO THE MED RNG FCST WHICH FEATURES THE PSSG OF A CANADIAN
CDFNT ON SAT...FOLLOWED BY MUCH MORE COMFORTABLE CONDITIONS. BEST
CHCS FOR TSRA APPEAR TO BE OVER NRN SXNS ON FRI NGT...SPREADING
INTO CNTRL NY AND NE PA ON SAT. POTNL FOR STRONG/SVR TSRA ON SAT GIVEN
THE MDL FCST WIND FIELDS AND INSTABILITY...WITH TIMING OF FNT
LOOKING QUITE FVRBL FOR SRN/CNTRL NY AND NE PA ON SAT. XPCT
LINGERING ACTIVITY TO PUSH OFF TO THE SE ON SAT NGT...WITH FAIR WX
AND MORE SEASONABLE TEMPS RETURNING ON SUNDAY. EARLY NXT WEEK
LOOKING FABULOUS WITH MAXES 75-80 AND LOWS INTO THE 50S...AND MUCH
LOWER HUMIDITY.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
HI PRES SFC AND ALOFT WITH VFR PREVAILING THRU 18Z WED. XPCT SCT
4-5 KFT CU DURING DAY...AND MAINLY SKC TNGT. ONLY EXCEPTION TO VFR
WILL BE VLY FOG/STRATUS LATE TNGT AFFECTING ELM IN THE 07-13Z
TIME FRAME. WINDS THIS AFTN NW TO NRLY 10 KTS...L&V TNGT...THEN
WRLY ON WED 10 KTS.
.OUTLOOK...
WED NGT/THU/FRI...VFR PREVAILS. CHANCE FOR LATE NGT/EARLY MRNG MVFR/IFR
FG/BR/HZ AT KELM. ISOLD OR WDLY SCT AFTN TSRA MAY ALSO PRODUCE
BRIEF RESTRICTIONS.
FRI NGT INTO SAT...MVFR IN TSRA...MOST NUMEROUS OVER NRN SITES FRI
NGT...AND AREA WIDE ON SAT.
SAT NGT...MVFR PSBL AT AVP IN SHRA/TSRA EARLY....IMPRVG TO VFR CNTRL
NY.
SUN...VFR.
&&
.CLIMATE...
BELOW ARE THE RECORD HIGHS FOR THE NEXT FEW DAYS AT OUR MAIN AIRPORTS
AND OUR FORECAST HIGHS. HIGH TEMPERATURES SHOULD FALL SHORT OF THE DAILY
RECORDS...
SYRACUSE HANCOCK FIELD...
TODAY 97 SET IN 1988. FORECAST 92
WEDNESDAY 94 SET IN 1999. FORECAST 92
THURSDAY 97 SET IN 1953. FORECAST 91
GREATER BINGHAMTON AIRPORT...
TODAY 98 SET IN 1988. TODAY`S FORECAST 88
WEDNESDAY 91 SET IN 1991. FORECAST 88
THURSDAY 93 SET IN 1953. FORECAST 89
SCRANTON/WILKES-BARRE INTERNATIONAL AIRPORT...
TODAY 101 SET IN 1988. TODAY`S FORECAST 92
WEDNESDAY 96 SET IN 1999. FORECAST 94
THURSDAY 98 SET IN 1953. FORECAST 93
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...HEAT ADVISORY FROM NOON TO 8 PM EDT WEDNESDAY FOR NYZ016>018.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...MDP
LONG TERM...
AVIATION...
CLIMATE...DJN
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1004 PM CDT WED JUL 17 2013
.UPDATE...
ISSUED AT 959 PM CDT WED JUL 17 2013
AS EXPECTED MOST OF THE CONVECTION ALONG THE FRONTAL BOUNDARY HAS
WEAKENED SUBSTANTIALLY SINCE 01Z. WINDS INDICATE THE BOUNDARY HAS
SLIPPED SOUTH OF FARGO-MOORHEAD AT 03Z...WITH WINDS INDICATING
BOUNDARY FROM SOUTH OF BEMIDJI TO NORTH OF DETROIT LAKES THEN JUST
SOUTH OF FARGO THEN BACK SOUTH OF VALLEY CITY-JAMESTOWN TO LOW
WEST OF BISMARCK.
WEAK 850 MB WARM ADVECTION ONGOING CURRENTLY WILL LIKELY CONTINUE
ISOLD SHOWERS NEW FEW HOURS. QUESTION IS OVERNIGHT...RAP13
CONTINUE TO SHOW 25 KT LOW LEVEL JET AND PRETTY STRONG BUT NARROW
850 MB WARM ADVECTION ZONE NEAR HIGHWAY TWO REGION OVERNIGHT INTO
THU MORNING AND HRRR DOES BREAK OUT PRECIP NR 07Z BTWN MOT-BIS-JMS
AND MOVES IT EAST-NORTHEAST....SO WILL CERTAINLY MAINTAIN CHANCE
OF STORMS FOR THE OVERNIGHT NORTH OF THE BOUNDARY. THE SHOWERS
ALONG THE INTL BORDER HAVE WEAKENED CONSIDERABLY BUT STILL A FEW
AROUND.
UPDATE ISSUED AT 658 PM CDT WED JUL 17 2013
WARM FRONTAL BOUNDARY LOCATED JUST SOUTH OF BEMIDJI TO ADA THEN TO
NEAR JAMESTOWN. AS EXPECTED WITH DAYTIME HEATING A CU FIELD FORMED
ALONG THE BOUNDARY AND SOME SMALL TSTMS FORMED IN A SCATTERED
FASHION ALONG IT. STRONGEST CELL ATTM NORTHEAST OF BISMARCK. NOT
TOO MUCH TO KEEP THESE GOING PAST DARK SO THESE WILL DIE OFF. A
LARGER AREA OF MORE GENERAL LIGHT RAIN SPREADING THRU SE SASK INTO
SOUTHERN MANITOBA AND SKIRTING THE ND BORDER THIS EVE AND DID
INCREASE POPS TO HIGH CHC OR LIKELY RIGHT ALONG THE BORDER FOR
THIS RAIN. THIS RAIN ASSOC WITH 500 MB SHORT WAVE SHOWN ON WATER
VAPOR NR THE SK/MB/ND BORDER REGION.
BIGGEST QUESTION IS OVERNIGHT. RAP MODEL DOES HAVE A 25 KT 850 MB
JET AND WARM ADVECTION CENTERED FROM CNTRL ND INTO NORTH CENTRAL
MN IN THAT 08Z-12Z PERIOD AND WOULD EXPECT TO SEE AN INCREASE IN
STORM COVERAGE NEAR THIS REGION (OR NEAR HIGHWAY TWO) LATER
TONIGHT WITH MORE GENERAL SHOWERS FARTHER NORTH. SO DID MAINTAIN
AN INCREASE IN POPS OVERNIGHT NORTH AND EAST AREAS OF THE FCST AREA.
DID REMOVE OR DIMINISH POPS IN THE SOUTH TONIGHT AS DOUBT ANY
PRECIP SOUTH OF I-94 THRU 18Z THU AS THAT AREA IN THE WARM AND
CAPPED AIRMASS AND SOUTH OF ANY LOW LEVEL JET INTERACTIONS.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 256 PM CDT WED JUL 17 2013
CURRENT SATELLITE SHOWS CU BEGINNING TO DEVELOP ALONG STAGNANT
WARM FRONTAL BOUNDARY STRETCHED ACROSS MY SOUTH...ROUGHLY ALONG A
BJI TO JMS LINE. POOL OF 70+ DEW POINTS ARE JUST SOUTH OF THE
BOUNDARY WITH DEW POINTS IN THE MID 50S ACROSS THE NORTH. CAPES
AROUND 2500 J/KG ACROSS THE SOUTH LACK THE SHEAR FOR ANY
SIGNIFICANT ACTIVITY THIS EVENING...BUT WILL PUT IN ISOLATED
STORMS ALONG THE FRONTAL BOUNDARY INTO THE MID EVENING HOURS.
40+ KT SHEAR BOUNDARY RUNS ROUGHLY ALONG THE HWY 200 CORRIDOR AND
NORTH...SO AGAIN NO SIGNIFICANT SHEAR IN OUR MOST HEATED OUT
REGION. GENERALLY USING A NAM/WRF BLEND THROUGH 06Z THEN
TRANSITION TO A MODEL BLEND FOR MAIN EVENT ON THURSDAY.
FORECAST CHALLENGE WILL BE SEVERE POTENTIAL ON THURSDAY.
LATE AFTERNOON/EARLY EVENING...COULD SEE SOME ISOLATED STORMS
ALONG BOUNDARY IN THE SOUTH...HOWEVER THERE IS A LACK OF 0 TO 6 KM
SHEAR.
TONIGHT...WARM FRONTAL BOUNDARY WILL BEGIN TO DRIFT NORTH AS LOW
PRESSURE STRENGTHENS AND MOVES INTO THE WRN DAKOTAS. ISENTROPIC
LIFT/WARM ADVECTION WITH A VERY MOIST AIRMASS WILL HELP INITIATE
SHOWERS/TSTMS ACROSS THE NORTH...IN REGION OF STRONGER SHEAR
ALOFT. THEREFORE COULD SEE SOME STRONG STORMS AFT AROUND
09Z...WHEN MODELS MOST AGREE ON PLACEMENT/TIMING OF PRECIP.
THURSDAY...WARM FRONTAL BOUNDARY WILL LIFT NORTHWARD TO ALONG THE
HWY 200 CORRIDOR BY 12Z AND NORTH OF GFK BY 18Z. SOUTHERN HALF OF
THE CWA SHOULD HEAT UP MUCH LIKE TODAY...WITH CAPES NEARING 3K
J/KG BY MID AFTN. FRONTAL BOUNDARY WILL BE FURTHER NORTH AND
MODELS SHOWING SHEAR VALUES OF 50 KT ALONG INTL BORDER. SEVERE
THREAT CONTINUES ALONG THE NORTHERN THIRD OF THE CWA...WITH
SOUTHERN TWO THIRDS MORE QUESTIONABLE DUE TO CONVECTIVE
INHIBITION. ALTHOUGH FREEZING LEVELS WILL BE QUITE HIGH...LARGE
HAIL A GOOD POSSIBILITY. ALSO A THREAT FOR TORNADOES WITH SFC
BOUNDARY ACROSS NORTHERN ZONES. POTENTIAL EXISTS FOR HEAT
ADVISORY CRITERIA ACROSS SOUTHERN HALF OF CWA. CURRENT FCST HOURLY
TEMPS ARE A COUPLE OF DEG TWO LOW TO ISSUE AT THIS POINT...AND
WILL PUNT TO EVENING SHIFT TO ASSESS 00Z MODEL RUNS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 256 PM CDT WED JUL 17 2013
FRIDAY AND SATURDAY...NORTHWEST FLOW PATTERN BEHIND DEPARTING SYSTEM
WILL BRING A CHANCE FOR SOME ISOLATED SHOWERS/TSTMS ON
FRIDAY...MAINLY IN THE EAST...WITH MODELS DIFFERING ON TIMING.
SIGNIFICANT DIFFERENCES BETWEEN MID RANGE MODELS FOR END OF THE WEEK
ON INTO THE WEEKEND...WITH GFS DROPPING HIGH PRESSURE INTO THE
MANITOBA LAKES REGION WITH MUCH COOLER AIR FILTERING INTO NORTH
DAKOTA (UPPER 60S). ECMWF BRINGS HIGH PRESSURE FURTHER
EAST...ALLOWING RETURN FLOW/WARM ADVECTION TO BRING MAX TEMPS INTO
THE MID TO UPPER 70S. WILL KEEP CONSALL BLEND GOING FOR THIS
PERIOD..HOWEVER THINK GFS-LIKE TEMPS WOULD BE WISHFUL THINKING FOR
MID JULY. CONSALL IS ONLY SLIGHTLY COOLER THAN ECMWF...WHICH IS
STILL COOLER THAN SEASONAL NORMS...SO SATURDAY SHOULD BE PLEASANT
EITHER WAY.
SUNDAY-WEDNESDAY...UPPER FLOW WILL BE MORE NORTHWEST DURING THIS
PERIOD ACCORDING TO THE EXTENDED MODELS. SHORTWAVES WITHIN THIS
PATTERN WILL BE HARD TO TIME. ANTICIPATE A MOSTLY DRY PERIOD WITH
ISOLATED TO SCATTERED THUNDERSTORMS. THE BEST THUNDERSTORM CHANCES
APPEAR TO BE WITH A STRONGER FROPA ON MONDAY...ALTHOUGH COVERAGE
SHOULD BE LIMITED. TEMPERATURES WILL BE NEAR NORMAL VALUES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 658 PM CDT WED JUL 17 2013
ISSUE WITH TAFS WAS CONVECTION. CONFIDENCE IS QUITE LOW AT ANY ONE
SPOT TO HIT WITH TIMING OF TSTMS. DID KEEP IDEA FROM PREV FCST OF
SOME VCTS TOWARD 09Z AT DVL AND 12Z AT GFK/TVF AND 14Z AT BJI FOR
LATE NIGHT/THU AM CONVECTION...BUT CONFIDENCE IS QUITE LOW. EXPECT
TO SEE NORTHEAST TO EAST WIND 10 KS OR LESS DVL-GFK-TVF TIL LATE
TONIGHT OR THU AM THEN WARM FRONT MAY SLIP THRU AND WINDS TURN
SOUTH-SOUTHEAST. BJI VARIABLE WIND WITH FRONT OVERHEAD THIS EVE
TURNING MORE SOUTH BY 12Z THU AND FARGO SEEING A SOUTH WIND THRU
18Z THU NR 10 KTS....WITH SOME GUSTS SOUTH-SOUTHWEST WINDS TO 20
KTS OR A BIT HIGHER THUR MIDDAY-AFTN. EXPECTING TO HAVE VFR CLOUD
CONDITIONS....THOUGH CERTAINLY DURING ANY STORM COULD HAVE BRIEF
MVFR CONDITIONS IN CIGS OR VSBY.
ELBOW LAKE AWOS HAS SOME ISSUES WITH VSBYS/CLOUD AND FAA
MAINTENANCE NOTIFIED.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...RIDDLE
SHORT TERM...SPEICHER
LONG TERM...TG/SPEICHER
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
707 PM CDT WED JUL 17 2013
.UPDATE...
ISSUED AT 658 PM CDT WED JUL 17 2013
WARM FRONTAL BOUNDARY LOCATED JUST SOUTH OF BEMIDJI TO ADA THEN TO
NEAR JAMESTOWN. AS EXPECTED WITH DAYTIME HEATING A CU FIELD FORMED
ALONG THE BOUNDARY AND SOME SMALL TSTMS FORMED IN A SCATTERED
FASHION ALONG IT. STRONGEST CELL ATTM NORTHEAST OF BISMARCK. NOT
TOO MUCH TO KEEP THESE GOING PAST DARK SO THESE WILL DIE OFF. A
LARGER AREA OF MORE GENERAL LIGHT RAIN SPREADING THRU SE SASK INTO
SOUTHERN MANITOBA AND SKIRTING THE ND BORDER THIS EVE AND DID
INCREASE POPS TO HIGH CHC OR LIKELY RIGHT ALONG THE BORDER FOR
THIS RAIN. THIS RAIN ASSOC WITH 500 MB SHORT WAVE SHOWN ON WATER
VAPOR NR THE SK/MB/ND BORDER REGION.
BIGGEST QUESTION IS OVERNIGHT. RAP MODEL DOES HAVE A 25 KT 850 MB
JET AND WARM ADVECTION CENTERED FROM CNTRL ND INTO NORTH CENTRAL
MN IN THAT 08Z-12Z PERIOD AND WOULD EXPECT TO SEE AN INCREASE IN
STORM COVERAGE NEAR THIS REGION (OR NEAR HIGHWAY TWO) LATER
TONIGHT WITH MORE GENERAL SHOWERS FARTHER NORTH. SO DID MAINTAIN
AN INCREASE IN POPS OVERNIGHT NORTH AND EAST AREAS OF THE FCST AREA.
DID REMOVE OR DIMINISH POPS IN THE SOUTH TONIGHT AS DOUBT ANY
PRECIP SOUTH OF I-94 THRU 18Z THU AS THAT AREA IN THE WARM AND
CAPPED AIRMASS AND SOUTH OF ANY LOW LEVEL JET INTERACTIONS.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 256 PM CDT WED JUL 17 2013
CURRENT SATELLITE SHOWS CU BEGINNING TO DEVELOP ALONG STAGNANT
WARM FRONTAL BOUNDARY STRETCHED ACROSS MY SOUTH...ROUGHLY ALONG A
BJI TO JMS LINE. POOL OF 70+ DEW POINTS ARE JUST SOUTH OF THE
BOUNDARY WITH DEW POINTS IN THE MID 50S ACROSS THE NORTH. CAPES
AROUND 2500 J/KG ACROSS THE SOUTH LACK THE SHEAR FOR ANY
SIGNIFICANT ACTIVITY THIS EVENING...BUT WILL PUT IN ISOLATED
STORMS ALONG THE FRONTAL BOUNDARY INTO THE MID EVENING HOURS.
40+ KT SHEAR BOUNDARY RUNS ROUGHLY ALONG THE HWY 200 CORRIDOR AND
NORTH...SO AGAIN NO SIGNIFICANT SHEAR IN OUR MOST HEATED OUT
REGION. GENERALLY USING A NAM/WRF BLEND THROUGH 06Z THEN
TRANSITION TO A MODEL BLEND FOR MAIN EVENT ON THURSDAY.
FORECAST CHALLENGE WILL BE SEVERE POTENTIAL ON THURSDAY.
LATE AFTERNOON/EARLY EVENING...COULD SEE SOME ISOLATED STORMS
ALONG BOUNDARY IN THE SOUTH...HOWEVER THERE IS A LACK OF 0 TO 6 KM
SHEAR.
TONIGHT...WARM FRONTAL BOUNDARY WILL BEGIN TO DRIFT NORTH AS LOW
PRESSURE STRENGTHENS AND MOVES INTO THE WRN DAKOTAS. ISENTROPIC
LIFT/WARM ADVECTION WITH A VERY MOIST AIRMASS WILL HELP INITIATE
SHOWERS/TSTMS ACROSS THE NORTH...IN REGION OF STRONGER SHEAR
ALOFT. THEREFORE COULD SEE SOME STRONG STORMS AFT AROUND
09Z...WHEN MODELS MOST AGREE ON PLACEMENT/TIMING OF PRECIP.
THURSDAY...WARM FRONTAL BOUNDARY WILL LIFT NORTHWARD TO ALONG THE
HWY 200 CORRIDOR BY 12Z AND NORTH OF GFK BY 18Z. SOUTHERN HALF OF
THE CWA SHOULD HEAT UP MUCH LIKE TODAY...WITH CAPES NEARING 3K
J/KG BY MID AFTN. FRONTAL BOUNDARY WILL BE FURTHER NORTH AND
MODELS SHOWING SHEAR VALUES OF 50 KT ALONG INTL BORDER. SEVERE
THREAT CONTINUES ALONG THE NORTHERN THIRD OF THE CWA...WITH
SOUTHERN TWO THIRDS MORE QUESTIONABLE DUE TO CONVECTIVE
INHIBITION. ALTHOUGH FREEZING LEVELS WILL BE QUITE HIGH...LARGE
HAIL A GOOD POSSIBILITY. ALSO A THREAT FOR TORNADOES WITH SFC
BOUNDARY ACROSS NORTHERN ZONES. POTENTIAL EXISTS FOR HEAT
ADVISORY CRITERIA ACROSS SOUTHERN HALF OF CWA. CURRENT FCST HOURLY
TEMPS ARE A COUPLE OF DEG TWO LOW TO ISSUE AT THIS POINT...AND
WILL PUNT TO EVENING SHIFT TO ASSESS 00Z MODEL RUNS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 256 PM CDT WED JUL 17 2013
FRIDAY AND SATURDAY...NORTHWEST FLOW PATTERN BEHIND DEPARTING SYSTEM
WILL BRING A CHANCE FOR SOME ISOLATED SHOWERS/TSTMS ON
FRIDAY...MAINLY IN THE EAST...WITH MODELS DIFFERING ON TIMING.
SIGNIFICANT DIFFERENCES BETWEEN MID RANGE MODELS FOR END OF THE WEEK
ON INTO THE WEEKEND...WITH GFS DROPPING HIGH PRESSURE INTO THE
MANITOBA LAKES REGION WITH MUCH COOLER AIR FILTERING INTO NORTH
DAKOTA (UPPER 60S). ECMWF BRINGS HIGH PRESSURE FURTHER
EAST...ALLOWING RETURN FLOW/WARM ADVECTION TO BRING MAX TEMPS INTO
THE MID TO UPPER 70S. WILL KEEP CONSALL BLEND GOING FOR THIS
PERIOD..HOWEVER THINK GFS-LIKE TEMPS WOULD BE WISHFUL THINKING FOR
MID JULY. CONSALL IS ONLY SLIGHTLY COOLER THAN ECMWF...WHICH IS
STILL COOLER THAN SEASONAL NORMS...SO SATURDAY SHOULD BE PLEASANT
EITHER WAY.
SUNDAY-WEDNESDAY...UPPER FLOW WILL BE MORE NORTHWEST DURING THIS
PERIOD ACCORDING TO THE EXTENDED MODELS. SHORTWAVES WITHIN THIS
PATTERN WILL BE HARD TO TIME. ANTICIPATE A MOSTLY DRY PERIOD WITH
ISOLATED TO SCATTERED THUNDERSTORMS. THE BEST THUNDERSTORM CHANCES
APPEAR TO BE WITH A STRONGER FROPA ON MONDAY...ALTHOUGH COVERAGE
SHOULD BE LIMITED. TEMPERATURES WILL BE NEAR NORMAL VALUES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 658 PM CDT WED JUL 17 2013
ISSUE WITH TAFS WAS CONVECTION. CONFIDENCE IS QUITE LOW AT ANY ONE
SPOT TO HIT WITH TIMING OF TSTMS. DID KEEP IDEA FROM PREV FCST OF
SOME VCTS TOWARD 09Z AT DVL AND 12Z AT GFK/TVF AND 14Z AT BJI FOR
LATE NIGHT/THU AM CONVECTION...BUT CONFIDENCE IS QUITE LOW. EXPECT
TO SEE NORTHEAST TO EAST WIND 10 KS OR LESS DVL-GFK-TVF TIL LATE
TONIGHT OR THU AM THEN WARM FRONT MAY SLIP THRU AND WINDS TURN
SOUTH-SOUTHEAST. BJI VARIABLE WIND WITH FRONT OVERHEAD THIS EVE
TURNING MORE SOUTH BY 12Z THU AND FARGO SEEING A SOUTH WIND THRU
18Z THU NR 10 KTS....WITH SOME GUSTS SOUTH-SOUTHWEST WINDS TO 20
KTS OR A BIT HIGHER THUR MIDDAY-AFTN. EXPECTING TO HAVE VFR CLOUD
CONDITIONS....THOUGH CERTAINLY DURING ANY STORM COULD HAVE BRIEF
MVFR CONDITIONS IN CIGS OR VSBY.
ELBOW LAKE AWOS HAS SOME ISSUES WITH VSBYS/CLOUD AND FAA
MAINTENANCE NOTIFIED.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...RIDDLE
SHORT TERM...SPEICHER
LONG TERM...TG/SPEICHER
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1150 PM CDT MON JUL 15 2013
.UPDATE...
ISSUED AT 1147 PM CDT MON JUL 15 2013
LINE OF WEAKENING COVNECTION MOVING INTO BOTTINEAU AND APPROACHING
TOWNER TO NORTHWEST OF GARRISION. HRRR STILL HAS ACTIVITY MOVING
EAST INTO DVL BASIN 06Z-09Z PERIOD AND WEAKLY INTO NRN VALLEY
PERHAPS AFTER THAT BEFORE DYING OFF. DID TWEEK POPS BASED ON THIS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 304 PM CDT MON JUL 15 2013
CONVECTION CHANCES WILL BE THE MAIN CHALLENGE THROUGHOUT THE
PERIOD.
THE UPPER RIDGE OVER THE EASTERN CONUS CONTINUES TO BUILD INTO THE
CENTRAL PART OF THE CONUS...WITH A SHORTWAVE TROUGH OVER SASK THAT
SHOULD MOVE THROUGH SOUTHERN CANADA TONIGHT. RAIN SHOWERS HAVE
CONTINUED IN A BAND ALONG AN OLD FRONTAL BOUNDARY FROM THE
SOUTHWESTERN CWA TO FARGO AND PARK RAPIDS. SHORT RANGE MODELS ALL
HAVE THIS BAND OF RAIN SLOWLY LIFTING NORTH FOR THE REST OF THE
AFTERNOON BEFORE DISSIPATING THIS EVENING AS THE FRONT WASHES OUT.
WITH INSTABILITY LIMITED BY THE CLOUDS AND RAIN FOR MUCH OF THE
DAY...SHOWERS WITH ONLY AN ISOLATED THUNDER MENTION SEEM
REASONABLE. THE NEXT CHANCE FOR PRECIP WILL ARRIVE IN OUR
NORTHWESTERN CWA LATER TONIGHT AS THE SHORTWAVE OVER CANADA MOVES
EAST AND HELPS PUSH A TROUGH AXIS INTO CENTRAL ND. THINK THAT MOST
ACTIVITY WILL BE OVER THE WESTERN PART OF THE STATE BUT SOME COULD
HOLD TOGETHER LONG ENOUGH TO IMPACT THE DEVILS LAKE BASIN SO KEPT
AROUND 30 POPS THERE.
THE UPPER RIDGE WILL CONTINUE TO BUILD WESTWARD THROUGH
TOMORROW...WITH THE MAIN WESTERLIES LIFTING JUST TO OUR NORTH.
MODELS ARE ALL IN PRETTY DECENT AGREEMENT ON DROPPING A WEAK COLD
FRONT INTO THE CWA AND STALLING IT OUT...ALTHOUGH THERE ARE
DIFFERENCES IN EXACTLY WHERE IT SETS UP. MOST SEEM TO STALL THE
BOUNDARY OVER THE NORTHERN TO CENTRAL CWA...AND WITH MOISTURE AND
INSTABILITY POOLING ON THE NORTH SIDE OF THE BOUNDARY...IT COULD
BE A FOCUS FOR CONVECTION TUESDAY AFTERNOON AND EVENING. DEEP
LAYER SHEAR IS NOT HUGELY IMPRESSIVE SO ANY SEVERE WILL BE
ISOLATED AT BEST. THE FRONT WILL CONTINUE TO WOBBLE OVER THE AREA
THROUGH TUESDAY NIGHT...SO CONTINUED TO KEEP POPS GOING FOR OUR
NORTHERN COUNTIES.
AS FOR TEMPERATURES...MUCH WILL DEPEND ON EXACTLY HOW CLOUDS AND
PRECIP PLAY OUT. FOR NOW KEPT LOWS MAINLY IN THE 60S AND HIGHS IN
THE UPPER 70S TO 80S...WITH HIGHEST VALUES IN THE SOUTHERN CWA
AND COOLEST IN THE NORTH WHERE THE FRONTAL BOUNDARY AS WELL AS
CLOUDS ARE MOST LIKELY TO BE FOUND.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 304 PM CDT MON JUL 15 2013
WEDNESDAY...THE MODELS SHOW SOME INDICATION OF THE FRONT SAGGING
SOUTH A LITTLE BIT. CONTINUED TO KEEP SCATTERED POPS GOING A BIT
FURTHER SOUTH THAN TUESDAY. THINK A MORE SIGNIFICANT CHANCE FOR
CONVECTION WILL ARRIVE ON THURSDAY AS 500MB HEIGHTS BEGIN TO FALL
ACROSS THE AREA AS A SHORTWAVE TROUGH DIGS INTO SOUTHERN CANADA.
THE SFC FRONT WILL LIFT BACK NORTH A BIT...AND THEN DROP SOUTH AS
A COLD FRONT BY LATE THURSDAY. WITH THE MAIN WESTERLIES BACK OVER
THE AREA...DEEP LAYER SHEAR WILL BE AROUND 40-50 KTS AND MODELS
SHOW SOME STRONG INSTABILITY NEAR THE BOUNDARY. KEPT CHANCES FOR
THUNDERSTORMS HIGH FOR THURSDAY.
FOR THURSDAY NIGHT THROUGH MONDAY THE REGION WILL ESSENTIALLY
REMAIN IN NORTHWEST FLOW ALOFT. LOOKS LIKE THERE COULD BE SUBTLE
WAVES IN THE FLOW WHICH COULD HELP INITIATE SOME LOW END
CONVECTIVE CHANCES THU THROUGH SUN. BETTER CHANCES FOR PCPN MAY
COME WITH A STRONGER WAVE AND FRONT SOMETIME ON MONDAY ALTHOUGH
MODELS ARE NOT IN VERY GOOD AGREEMENT BY THEN. SHOULD BE A
NORTHEAST TO SOUTHWEST TEMP GRADIENT WITH THE NORTHWEST FLOW UNTIL
SUNDAY WHEN TEMPS RISE AHEAD OF THE NEXT WAVE AND FRONT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1147 PM CDT MON JUL 15 2013
BEMIDJI AREA IS IN QUESTION OVERNIGHT INTO TUES AM DUE TO POSSIBLE
AREAS OF FOG AND LOW CLOUDS. OTHERWISE MUCH OF THE STRATOCU DECK
HAS BROKEN UP LEAVING PATCHY CLOUD COVER. DO EXPECT SOME MID LEVEL
CLOUD AND HIGH CLOUD TO MOVE IN FROM THE WEST WITH TSTM AREA
ACROSS THE NE ND/FAR NW MN LATER TONIGHT INTO TUESDAY. KEPT TEMPO
FOR TSRA AT DVL AIRPORT FOR 07Z-09Z PERIOD...BUT NOT IN GFK DUE TO
LESS CHANCE OF IT MAKING IT THIS FAR EAST. FRONTAL WIND SHIFT
SHOULD REACH DVL MIDDAY AND GFK-TVF BY LATE AFTN.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...RIDDLE
SHORT TERM...JR
LONG TERM...JR/GODON
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
926 PM EDT WED JUL 17 2013
.SYNOPSIS...
A LARGE AREA OF HIGH PRESSURE WILL CONTINUE TO DOMINATE THE
WEATHER ACROSS THE OHIO VALLEY THROUGH THURSDAY. THE HIGH WILL
BEGIN TO BREAK DOWN AND DRIFT SOUTH ON FRIDAY. THIS WILL ALLOW A
COLD FRONT TO DROP ACROSS THE AREA ON SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
TEMPS HAVE STARTED TO FALL SO HEAT ADVISORY HAS BEEN ALLOWED TO
EXPIRE FOR NOW. CONVECTION HAS DISSIPATED AGAIN THIS EVENING AS
EXPECTED. HRRR AND RUC DO ALLOW A BRIEF ISOLATED CONVCTIVE CELL TO
DEVELOP HERE AND THERE OVERNIGHT BUT OTHER THAN THE LEFTOVER CELLS
IN CANADA DROPPING SE TOWARD LERI THINK THE AIRMASS IS TOO CAPPED
FOR ANYTHING TO DEVELOP ELSEWHERE.
ANOTHER WARM AND MUGGY NIGHT. SOME PATCHY FOG MAY DEVELOP BUT NOT
EXPECTING A LOT.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY NIGHT/...
NO BIG CHANGES IN STORE FOR THURSDAY. CERTAINLY POSSIBLE TO GET A
ROGUE THUNDERSTORM WITH THE INSTABILITY SIMILAR TO TODAY BUT FOR
NOW WILL HAVE NO MENTION GIVEN LOW PROBABILITY. ISSUED A HEAT
ADVISORY FOR THURSDAY WITH HIGHS A DEGREE OR SO HIGHER DURING THE
AFTERNOON WITH SIMILAR DEWPOINTS. SHOULD AGAIN HAVE HEAT INDEX
CLOSE TO 100. THURSDAY NIGHT INTO FRIDAY WESTERLIES BEGIN TO
DESCEND ACROSS THE AREA AS UPPER HIGH AXIS SHIFTS SOUTH. WILL HAVE
SLIGHT CHANCE POPS FOR FRIDAY AFTERNOON AND THEN INCREASE TO HIGH
CHANCE AND LIKELY POPS IN ADVANCE OF AND WITH THE FRONT FRIDAY
NIGHT AND SATURDAY. TEMPS AROUND 90 OR A BIT HIGHER THURSDAY AND
FRIDAY. LOW TO MID 80S SATURDAY.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
HIGH PRESSURE ACROSS THE CENTRAL GREAT LAKES STAYS NORTH OF OUR
AREA...SLIDING EAST EARLY NEXT WEEK. THEREFORE AREA WILL GET A
REPRIEVE FROM RECENT HEAT AND TEMPERATURES WILL BE SITTING CLOSE TO
NORMALS. SUNDAY/SUNDAY NIGHT WILL BE DRY WITH HIGH PRESSURE
OVERHEAD...BUT LESS CERTAINTY INTO MONDAY AND TUESDAY WITH SOME
RETURNING MOISTURE TO THE AREA. THE BIG PICTURE KEEPS A MODERATE
TROUGH ACROSS THE NORTHERN TWO THIRDS OF THE EAST U.S. ANY TRUE
FRONTAL PASSAGE LOOKS TO HOLD OFF UNTIL MID WEEK.
&&
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
ROGUE STORMS OVER NW OH APPEAR TO BE DIMINISHING. WILL GO WITH A
DRY FORECAST. THERE SHOULD JUST BE JUST SOME HIGH CLOUDS OVERNIGHT
WITH MORE CU TOMORROW. THERE WILL LIKELY MORE ISOLATED STORMS
TOMORROW BUT TOUGH TO PINPOINT AT THIS TIME. THE FLOW WILL LIGHT.
.OUTLOOK...NON VFR IN PATCHY EARLY MORNING FOG.
&&
.MARINE...
HIGH PRESSURE ACROSS THE AREA SLOWLY WEAKENS THROUGH FRIDAY. A COLD
FRONT WILL BE CROSSING THE GREAT LAKES BETWEEN FRIDAY AND SATURDAY.
WINDS AHEAD OF THIS FRONT WILL PICK UP SOME...LIKELY GENERATING 3 TO
5 FOOT WAVES IN THE EASTERN OPEN WATERS FRIDAY AFTERNOON. SMALL
CRAFT ADV CONDITIONS FOR THE NEARSHORE WATERS WILL LIKELY BE DELAYED
UNTIL THE FRONTAL PASSAGE...FOR FRIDAY NIGHT AND SATURDAY.
SHOWERS/THUNDERSTORMS WILL ACCOMPANY THIS COLD FRONT. HIGH PRESSURE
FOLLOWS IN ITS WAKE OVER THE REST OF THE WEEKEND...KEEPING A LIGHTER
NORTH FLOW ACROSS LAKE ERIE.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...HEAT ADVISORY FROM 1 PM TO 8 PM EDT THURSDAY FOR OHZ003-
006>011-013-017>023-027>033-036>038-047.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TK
NEAR TERM...ADAMS/TK
SHORT TERM...TK
LONG TERM...OUDEMAN
AVIATION...KUBINA
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
820 PM EDT WED JUL 17 2013
.SYNOPSIS...
HIGH PRESSURE ATOP THE REGION WILL CONTINUE TO WEAKEN AND GIVE WAY TO A
SOUTHERLY RETURN FLOW THROUGH THE END OF THE WORK WEEK. A WEAK COLD
FRONT WILL THEN APPROACH THE CAROLINAS LATER THIS WEEKEND.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 8 PM...CONVECTION CONTINUES OVER THE SW PORTION OF THE
CWFA...MAKING PROGRESS OUT OF OUR AREA HAVING LEFT FAIRLY STABLE
OUTFLOW IN ITS WAKE. HOWEVER A CLUSTER OF CELLS IS MOVING INTO THE
NRN MTNS...GENERALLY PROPAGATING SOUTHWESTWARD WITH THE MEAN FLOW.
21Z HRRR DID SEEM TO CAPTURE THIS ACTIVITY AND TAKES IT SOUTHWEST TO
AROUND THE FRENCH BROAD VALLEY BEFORE DYING IN 02-03Z TIMEFRAME. IT
WILL BE MOVING INTO AN AREA THAT WAS WORKED OVER BY MID-AFTERNOON
AND IT IS QUESTIONABLE HOW MUCH INSTABILITY REMAINS FOR IT TO WORK
WITH. NONETHELESS HAVE REFLECTED IT IN EVENING POPS SIMILAR TO HRRR.
THINK THE SW ACTIVITY WILL LEAVE BEHIND LIGHT RAIN AND SOME PATCHY
FOG BUT TRENDS SHOULD GENERALLY BE TO DIMINISH OVER THE NEXT COUPLE
HOURS.
AS OF EARLY WED AFTN...THE 12Z OBSERVED SOUNDINGS FROM KGSO AND KFFC
INDICATE THAT PW VALUES HAVE INCREASED TO 1.5 TO 1.9 INCHES. THE WBZ
HAS LIFTED TO 13.8 KFT AT KGSO AND 11.7 KFT AT KFFC. BOTH SOUNDINGS
INDICATED CAPE VALUES NEAR 3500 J/KG WITH SWEAT VALUES FROM 190 TO
300. IN ADDITION...0-3 KM HELICITY INCREASE FROM YESTERDAY TO AROUND
25 M2/S2...WITH STORM MOTIONS SW AROUND 10 KTS. THE LATEST MESOSCALE
ANALYSIS INDICATED THAT CAPE VALUES ACROSS THE REGION RANGED CLOSE
TO 3000 J/KG. DCAPES RANGES FROM 500-1000 J/KG. THIS ENVIRONMENT
SHOULD SUPPORT SEVERAL SEVERE THUNDERSTORMS INTO THIS
EVENING...PRODUCING BOTH LARGE HAIL AND DAMAGING WIND GUSTS.
BASED ON RADAR/SATELLITE TRENDS AND CONVECTION ALLOWING
MODEL...COVERAGE SHOULD CONTINUE TO INCREASE ACROSS THE MTNS AND NC
PIEDMONT THROUGH 330 PM. THE REST OF THE AFTERNOON...SCT TO NUM
STORMS WILL DEVELOP ACROSS THE FORECAST AREA. CONVECTION MAY LINGER
AN HOUR OR TWO BEYOND THE STANDARD DIURNAL CYCLE...SUPPORTED BY
WANING HIGH LEVELS OF AFTERNOON INSTABILITY. I WILL FORECAST SCT MTN
COVERAGE UNTIL 5Z. THE REST OF THE NIGHT WILL SEE CALM TO LIGHT
WINDS AND THINNING DEBRIS CLOUDS. AREAS THAT OBSERVE RAIN THIS
AFTERNOON AND EVENING WILL HAVE A STRONG CHC OF DEVELOPING FOG
AROUND SUNRISE THURS...ESPECIALLY WITHIN THE MTN VALLEYS. LOWS
RANGING VERY CLOSE TO THIS MORNING/S VALUES.
THURSDAY...LARGE MID LEVEL RIDGE CENTERED OVER THE OHIO RIVER VALLEY
WILL CONTINUE TO WEAKEN. HOWEVER...THE AXIS OF THE RIDGE IS EXPECTED
TO DESCEND ACROSS THE MID APPALACHIANS AND ATLANTIC STATES BY THE
AFTERNOON. NAM FORECAST SOUNDINGS INDICATE THAT A SUBSIDENCE
INVERSION WILL DEVELOP AROUND H65. HOWEVER...GIVEN FORECAST SFC
TEMPERATURES AND DEWPOINTS SIMILAR TODAY...CAPE VALUES SHOULD BE
COMPARABLE TO THIS AFTERNOON. THE DEVELOPMENT OF THE INVERSION WILL
LIKELY DELAY CONVECTION TO THE EARLY TO MID AFTERNOON. CONVECTION
ALLOWING MODELS AND NAM/GFS INDICATE THAT CONVECTION COVERAGE WILL
FAVOR THE MTNS THROUGH MID AFTERNOON. DURING THE LATE AFTERNOON AND
EARLY EVENING...ISO TO SCT COVERAGE SHOULD DEVELOP ACROSS THE
FOOTHILLS AND PIEDMONT.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AS OF 155 PM WEDNESDAY...THE UPPER RIDGE IS EXPECTED TO CONTINUE TO
WEAKEN DURING THE SHORT TERM...WHILE BECOMING ESTABLISHED FARTHER
SOUTH WITH TIME. THIS CREATES SOMEWHAT OF A CONUNDRUM IN DIAGNOSING
THE CONVECTIVE POTENTIAL ON FRIDAY...SINCE THE WEAKENING RIDGE WILL
BE MORE OR LESS POSITIONED OVER OUR AREA. WHILE THE MID-LEVELS OF
FORECAST SOUNDINGS ARE WARM...THEY ARE HARDLY CAPPED AND THE
SOUNDINGS ARE ALSO QUITE UNSTABLE. THEREFORE...HAVE OPTED FOR AN
ESSENTIALLY CLIMATOLOGICAL POP DISTRIBUTION...WITH LOW CHANCE ACROSS
THE PIEDMONT...AND SOLID CHANCE TO LIKELY ACROSS THE MTNS.
BY SATURDAY...HEIGHTS BEGIN TO FALL ACCORDING TO MODEL SOLUTIONS...
RESULTING IN A PATTERN SLIGHTLY MORE FAVORABLE FOR CONVECTION.
THEREFORE...POPS WILL BEGIN TO INCREASE ABOVE CLIMO BY SATURDAY
AFTERNOON...WITH GENERALLY MID TO HIGH CHANCES IN MOST AREAS.
TROPOSPHERIC FLOW AND LOW AND DEEP LAYER SHEAR WILL REMAIN WEAK...
SO THE USUAL MID-SUMMER THREATS OF PULSE SEVERE STORMS AND LOCALLY
HEAVY RAINFALL WILL PERSIST. TEMPS SHOULD REMAIN VERY CLOSE TO...OR
SLIGHTLY ABOVE CLIMO THROUGH THE PERIOD.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 210 PM TUESDAY...UNFORTUNATELY...THE GLOBAL MODELS SPELL A
RETURN TO A WETTER PATTERN DURING THE MEDIUM RANGE...AS AN UPPER
TROUGH IS EXPECTED TO BECOME ESTABLISHED ACROSS THE EASTERN CONUS BY
EARLY NEXT WEEK. IN ASSOCIATION WITH THIS PATTERN CHANGE...A FRONTAL
BOUNDARY IS PROGGED TO PUSH INTO THE SOUTHEAST AND MID-ATLANTIC BY
SUNDAY...SUPPORTING LIKELY POPS ACROSS THE ENTIRE FORECAST AREA.
ALTHOUGH THE MODELS DEPICT THIS FRONTAL ZONE AS BECOMING
ESTABLISHED/QUASI-STATIONARY EAST AND SOUTH OF THE FORECAST AREA
TOWARD THE END OF THE PERIOD...IT APPEARS THAT IMPACTS ON OUR
SENSIBLE WEATHER MAY BE MINIMAL...AS THE UPPER TROUGH WILL REMAIN TO
OUR WEST...SUPPORTING PLENTY OF MOISTURE AND INSTABILITY ACROSS THE
AREA THROUGH THE END OF THE PERIOD. THEREFORE...WHILE POPS LOWER
SOMEWHAT MON-WED FROM THEIR SUNDAY NADIR...THEY WILL REMAIN ABOVE
CLIMO THROUGH THE END OF THE PERIOD. SUCH A PATTERN SUGGESTS A
RETURN TO BELOW NORMAL TEMPS NEXT WEEK...AT LEAST DURING THE DAY.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
AT KCLT...CURRENTLY THINK CONVECTION IS OVER AT/NEAR THE FIELD FOR
THE EVENING. LITTLE DEVELOPMENT SEEN BEHIND MAIN LINE OF STORMS
WHICH PROGRESSED FROM THE NC PIEDMONT SOUTHWARD INTO SC THIS AFTN.
THIS SEEMS TO HAVE USED UP THE AVBL INSTABILITY...BUT A FEW LIGHT
SHOWERS REMAIN NEARBY AND MAY BRING SOME LIGHT PRECIP EARLY THIS
EVENING. HEAVY RA NEVER OCCURRED AT THE FIELD TODAY...WHICH MEANS
DRIER SOILS AND LIMITED FOG POSSIBILITIES OVERNIGHT. SOME GUIDANCE
DOES SUGGEST FOG NEAR DAYBREAK BUT THINK THEY MAY HAVE ASSUMED WET
SOILS. DIURNAL VFR CU WILL POP OUT BY MID MRNG WITH NEAR
CLIMATOLOGICAL THUNDER CHANCES IN THE AFTN...HENCE PROB30. LIGHT BUT
SOMEWHAT VARIABLE NE WINDS WILL PREVAIL LATE TONIGHT BECOMING
SOUTHERLY THURSDAY.
ELSEWHERE...VIGOROUS TSRA WILL CONTINUE THROUGH EARLY THIS
EVENING...BRINGING IFR AND WIND GUSTS OF 20-30 KT TO SOME SPOTS
EARLY IN THE PERIOD OVER THE SW NC MTNS AND THE SAVANNAH RIVER
VALLEY. THIS IS REFLECTED AT KAND...BUT OTHER SITES SHOULD REMAIN
VFR EXCEPT PERHAPS FOR SOME LIGHT PATCHY FOG WHERE HEAVY RA FELL
JUST BEFORE SUNSET /MAINLY NEAR KGSP-KGMU/. LIGHT AND GENERALLY NLY
WINDS OVERNIGHT. WET SOILS FROM THE TS TODAY WILL ENHANCE FOG
CHANCES AROUND DAYBREAK. GUIDANCE MOST UNIFORMLY FAVORS FOG AT KAVL
BUT THERE IS A DECENT CHANCE AT ALL THE SITES. DIURNAL CU WILL POP
OUT BY MID MORNING WITH CONTINUED LIGHT WINDS. THOUGH THUNDER
CHANCES ARE LOWER TOMORROW...THEY WILL BE NEAR CLIMATOLOGICAL
NORMALS FOR MID SUMMER...IN PROB30 RANGE FOR THE AFTN.
OUTLOOK...WEAK HIGH PRESSURE WILL LINGER THRU FRIDAY...THEN A COLD
FRONT WILL SAG SEWD INTO THE AREA THIS WEEKEND. NORMAL...IF NOT
ABOVE NORMAL COVERAGE OF MAINLY AFTN/EVE SHRA/TSRA EXPECTED ACRS THE
REGION EACH DAY INTO THIS WEEKEND.
CONFIDENCE TABLE...
00-06Z 06-12Z 12-18Z 18-24Z
KCLT HIGH 100% HIGH 89% HIGH 97% HIGH 100%
KGSP HIGH 100% HIGH 97% HIGH 100% HIGH 100%
KAVL HIGH 94% MED 63% HIGH 81% HIGH 100%
KHKY HIGH 86% MED 72% HIGH 85% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% MED 77% HIGH 91% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...GOODMAN
NEAR TERM...NED/WIMBERLEY
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...WIMBERLEY
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
254 PM MDT TUE JUL 16 2013
.SHORT TERM...THIS EVENING THROUGH WEDNESDAY NIGHT
ISSUED AT 253 PM MDT TUE JUL 16 2013
AT 20Z A MODERATE AMOUNT OF CU DEVELOPMENT WAS TAKING
PLACE ALONG THE COOL FRONT BOUNDAY ACROSS EXTREME NORTHWESTERN SOUTH
DAKOTA THIS AFTERNOON. NO LIGHTNING YET, BUT THE HRRR 17Z UPDATE
SHOWED SOME MINIMAL RW- ACTIVITY BETWEEN 00Z AND 02Z JUST BARELY
ACROSS THE NORTHWEST CORNER OF THE STATE. THE SOUTHEASTERN EDGE OF
THE SOUTHEASTERN MONTANA LOW ST FIELD MENTIONED IN THE MORNING
UPDATE WAS DISSIPATING AND RETREATING NORTHWARD AS THE CYCLONIC
CIRCULATION AROUND THE WEAK SURFACE LOW BECAME MORE EASTERLY IN THIS
REGION.
ON A LARGER SCALE THE RIDGE EXTENDING WESTWARD INTO THE CENTRAL
PLAINS HAS PRETTY MUCH CUT OFF SIGNIFICANT MOIST RETURN FLOW TO THE
DAKOTAS THIS AFTERNOON IN THE MID AND UPPER LEVELS . DEWPOINTS ARE
DOWN 10 TO 12 DEGREES FROM YESTERDAY AFTERNOON AND MODEL SOUNDINGS
SHOW A VERY DRY STABLE AIR MASS.
FOR WEDNESDAY THE WEAK COOL FRONT IS FORECAST TO DRIFT SOUTHWARD
ACROSS NORTHWEST SOUTH DAKOTA. HOWEVER THE WESTERLYS AND ANY UPPER
LEVEL IMPULSES WILL REMAIN WELL NORTH OF THE FORECAST AREA AND
AIRMASS MOISTURE WILL CONTINUE TO BE MINIMAL. TEMPERATURES ARE
FORECAST TO BE A DEGREE OR SO WARMER THAN THIS AFTERNOON.
&&
.LONG TERM...THURSDAY THROUGH TUESDAY
ISSUED AT 253 PM MDT TUE JUL 16 2013
VERY BROAD...FLAT LONG WAVE RIDGE OVER THE GREAT LAKES WILL
RETROGRESS TO THE PACIFIC COAST BY 12Z FRIDAY AND INCREASE SOMEWHAT
IN AMPLITUDE. GFS AND ECMWF BOTH SHOW THIS TREND. RESULT IS THAT
WEAK NORTHWESTERLY FLOW DEVELOPS OVER OUR CWA ON THURSDAY AND
FRIDAY ALLOWING A COLD FRONT TO MOVE ACROSS THE AREA. THIS WILL DROP
TEMPERATURES A BIT AND RESULT IN CHANCES FOR SCATTERED TSTM
DEVELOPMENT. UNCERTAINTY IN THE EXACT LOCATION OF THE RIDGE...THE
STRENGTH OF THE NORTHWESTERLY FLOW EAST OF IT...AND THE POSITION AND
TIMING OF SHORT WAVES EMBEDDED IN THIS FLOW ALL LEAD TO SUBSTANTIAL
UNCERTAINTY IN THE FORECAST FOR THE WEEKEND AND BEYOND. STAYED CLOSE
TO GUIDANCE WITH TEMPS AND PROBS.
&&
.AVIATION...FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON
ISSUED AT 253 PM MDT TUE JUL 16 2013
MAINLY VFR CONDITIONS WILL CONTINUE THROUGH THE PERIOD.
WEAK COLD FRONT AND SFC TROF WILL BRING NORTHERLY WINDS TO NE WY AND
NW SD THIS AFTN. FRONT WILL BECOME STNRY AND BECOME MORE DIFFUSE. AN
ISOLATED TSTM OR TWO POSSIBLE VCNTY OF THE FRONT THIS AFTN OVER
NORTHERN PORTIONS OF NE WY AND NW SD. SOUTHERLY SFC FLOW WILL
ENCOMPASS THE ENTIRE FCST AREA BY WED AFTN WITH VFR CONDS
CONTINUING.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
SHORT TERM...CARPENTER
LONG TERM...BARBER
AVIATION...BARBER
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1003 PM CDT WED JUL 17 2013
.UPDATE...
SCATTERED STORMS CONTINUE TO DEVELOP ALONG AND EAST OF THE CUMBERLAND
PLATEAU...WORKING SLOWLY WEST. UPPER HIGH CONTINUES TO LINGER OVER
THE MID-WEST/OH VALLEY BUT VERY WEAK INVERTED TROUGH/WAVE SHOWING
UP ACROSS THE APPALACHIANS HEADING WEST AS WELL. THIS WAVE MOVING
OVER THE CWA LITTLE LATER WILL DEEPEN MOISTURE SOME AS WELL AS KEEP
LARGE SCALE ACCENT GOING. CANT RULE OUT ISO TO POSSIBLY SCT STORMS
OVERNIGHT...ESPECIALLY EAST OF BNA. HAVE ADDED BACK FOR MOST OF
THE NIGHT. ALSO EXPECT STORMS TO DEVELOP FAIRLY EARLY TOMORROW
AFTER DYING OFF TOWARD MORNING...SO WILL ADJUST THERE AS WELL.
MINOR TEMP TWEAKS ALSO POSSIBLE.
&&
.PREV DISCUSSION... /ISSUED 805 PM CDT WED JUL 17 2013/
UPDATE...
AVIATION...
SHOWERS AND STORMS BEGINNING TO DEVELOP ON EAST SIDE OF PLATEAU
NEAR CROSSVILLE SO HAVE UPDATED TERMINAL FORECAST FOR CROSSVILLE
TO INCLUDE A CHANCE OF THUNDERSTORMS FOR THE NEXT SEVERAL HOURS.
LATEST RUC SHOWING UPPER LEVEL TROUGH OVER EASTERN TENNESSEE
APPROACHING PLATEAU.
BOYD
PREV DISCUSSION... /ISSUED 721 PM CDT WED JUL 17 2013/
UPDATE...FOR 00Z AVIATION FORECAST
AVIATION...
ISOLATED TO SCATTERED CONVECTION ON-GOING IN THE MID STATE AT THIS
TIME. THERE IS A PRETTY GOOD SWATH OF SHOWERS AND STORMS OVER
EASTERN TENNESSEE AND WESTERN CAROLINAS THAT MAY WORK WESTWARD
THIS EVENING AND OVERNIGHT INTO THE MID STATE. THIS ACTIVITY IS
ASSOCIATED WITH AN EASTERLY WAVE THATS BEEN PROGRESSING WESTWARD
WITH TIME. IF THIS TREND CONTINUES THIS ACTIVITY WILL REACH THE
PLATEAU AROUND 02Z-03Z AND CONTINUE WESTWARD LATE EVENING AND
OVERNIGHT. H-TRIPLE-R HI RES BRINGS THIS ACTIVITY UP TO INTERSTATE
65 BY 07Z. LOOK FOR SCATTERED CONVECTION DURING THE DAY ON
THURSDAY.
BOYD
PREV DISCUSSION... /ISSUED 541 PM CDT WED JUL 17 2013/
MESOSCALE UPDATE...
THUNDERSTORMS MOVING THROUGH GRUNDY COUNTY DROPPING RAINFALL OF
ONE TO 1.25 INCHES PER HOUR. STORMS SHOULD EXIT SHORTLY BUT WILL
HAVE TO WATCH UPSTREAM STORMS FOR TRAINING.
BOYD
PREV DISCUSSION... /ISSUED 309 PM CDT WED JUL 17 2013/
DISCUSSION...
CURRENT RADAR TRENDS INDICATE VERY ISOLATED SHOWERS ACROSS MIDDLE
TENNESSEE. VISIBLE SATELLITE IMAGERY SHOWS DIURNAL CU FIELD
DEVELOPED JUST AFTER 15Z TODAY...AND FIGURE THIS WILL BE THE TREND
OVER THE NEXT COUPLE OF DAYS BEFORE A FRONTAL BOUNDARY PUSHES DOWN
THIS WEEKEND. MODELS INDICATE A SLIGHT INCREASE IN MOISTURE FOR
THURSDAY AND FRIDAY...SO AM ANTICIPATING A CORRESPONDING SLIGHT
INCREASE IN SHOWER CHANCES THE NEXT TWO DAYS. UPSTREAM RADAR
TRENDS INDICATE A BROADER COVERAGE OF CONVECTION...AND EXPECT THIS
PATTERN TO SHIFT WESTWARD WHILE WEAKENING SOMEWHAT.
BETTER CHANCES FOR RAIN SHOWERS AND CONVECTION WILL BE THIS
WEEKEND AS FLOW SHIFTS AROUND TO THE SOUTHWEST AHEAD OF A WEAK
FRONTAL BOUNDARY THAT WILL PASS THROUGH BY SUNDAY EVENING. BEHIND
THE FRONT...THE FLOW REMAINS WESTERLY...SO EXPECT LITTLE IN THE
WAY OF RELIEF FROM THE WARM TEMPERATURES AND HUMIDITY. THE UPPER
TROUGH THAT IS EXPECTED TO SET UP OVER THE EASTERN HALF OF THE
U.S. WILL REMAIN IN PLACE THROUGH THE END OF THE FORECAST
PERIOD...WITH THE EXTENDED MODELS HINTING AT A RELIEF PERHAPS BY
NEXT WEEKEND.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
929 PM CDT WED JUL 17 2013
.MESOSCALE UPDATE...
EASTERLY WAVE AXIS NOW NEARING PLATEAU WITH ISOLATED THUNDERSTORMS
CROSSVILLE SOUTH TOWARD CHATTANOOGA AT 0230Z. THERES BEEN A STRONG
STORM OR TWO LAST HOUR ALONG THE PLATEAU IN THE CROSSVILLE AREA. WITH
WAVE WORKING WESTWARD TONIGHT EXPECT ISOLATED CONVECTION TO
CONTINUE IN THE MID STATE OVERNIGHT. OMEGA FIELDS ARE STRONGER
EASTERN AREAS AND PLATEAU.
BOYD
&&
.PREV DISCUSSION... /ISSUED 805 PM CDT WED JUL 17 2013/
UPDATE...
AVIATION...
SHOWERS AND STORMS BEGINNING TO DEVELOP ON EAST SIDE OF PLATEAU
NEAR CROSSVILLE SO HAVE UPDATED TERMINAL FORECAST FOR CROSSVILLE
TO INCLUDE A CHANCE OF THUNDERSTORMS FOR THE NEXT SEVERAL HOURS.
LATEST RUC SHOWING UPPER LEVEL TROUGH OVER EASTERN TENNESSEE
APPROACHING PLATEAU.
BOYD
PREV DISCUSSION... /ISSUED 721 PM CDT WED JUL 17 2013/
UPDATE...FOR 00Z AVIATION FORECAST
AVIATION...
ISOLATED TO SCATTERED CONVECTION ON-GOING IN THE MID STATE AT THIS
TIME. THERE IS A PRETTY GOOD SWATH OF SHOWERS AND STORMS OVER
EASTERN TENNESSEE AND WESTERN CAROLINAS THAT MAY WORK WESTWARD
THIS EVENING AND OVERNIGHT INTO THE MID STATE. THIS ACTIVITY IS
ASSOCIATED WITH AN EASTERLY WAVE THATS BEEN PROGRESSING WESTWARD
WITH TIME. IF THIS TREND CONTINUES THIS ACTIVITY WILL REACH THE
PLATEAU AROUND 02Z-03Z AND CONTINUE WESTWARD LATE EVENING AND
OVERNIGHT. H-TRIPLE-R HI RES BRINGS THIS ACTIVITY UP TO INTERSTATE
65 BY 07Z. LOOK FOR SCATTERED CONVECTION DURING THE DAY ON
THURSDAY.
BOYD
PREV DISCUSSION... /ISSUED 541 PM CDT WED JUL 17 2013/
MESOSCALE UPDATE...
THUNDERSTORMS MOVING THROUGH GRUNDY COUNTY DROPPING RAINFALL OF
ONE TO 1.25 INCHES PER HOUR. STORMS SHOULD EXIT SHORTLY BUT WILL
HAVE TO WATCH UPSTREAM STORMS FOR TRAINING.
BOYD
PREV DISCUSSION... /ISSUED 309 PM CDT WED JUL 17 2013/
DISCUSSION...
CURRENT RADAR TRENDS INDICATE VERY ISOLATED SHOWERS ACROSS MIDDLE
TENNESSEE. VISIBLE SATELLITE IMAGERY SHOWS DIURNAL CU FIELD
DEVELOPED JUST AFTER 15Z TODAY...AND FIGURE THIS WILL BE THE TREND
OVER THE NEXT COUPLE OF DAYS BEFORE A FRONTAL BOUNDARY PUSHES DOWN
THIS WEEKEND. MODELS INDICATE A SLIGHT INCREASE IN MOISTURE FOR
THURSDAY AND FRIDAY...SO AM ANTICIPATING A CORRESPONDING SLIGHT
INCREASE IN SHOWER CHANCES THE NEXT TWO DAYS. UPSTREAM RADAR
TRENDS INDICATE A BROADER COVERAGE OF CONVECTION...AND EXPECT THIS
PATTERN TO SHIFT WESTWARD WHILE WEAKENING SOMEWHAT.
BETTER CHANCES FOR RAIN SHOWERS AND CONVECTION WILL BE THIS
WEEKEND AS FLOW SHIFTS AROUND TO THE SOUTHWEST AHEAD OF A WEAK
FRONTAL BOUNDARY THAT WILL PASS THROUGH BY SUNDAY EVENING. BEHIND
THE FRONT...THE FLOW REMAINS WESTERLY...SO EXPECT LITTLE IN THE
WAY OF RELIEF FROM THE WARM TEMPERATURES AND HUMIDITY. THE UPPER
TROUGH THAT IS EXPECTED TO SET UP OVER THE EASTERN HALF OF THE
U.S. WILL REMAIN IN PLACE THROUGH THE END OF THE FORECAST
PERIOD...WITH THE EXTENDED MODELS HINTING AT A RELIEF PERHAPS BY
NEXT WEEKEND.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
805 PM CDT WED JUL 17 2013
.UPDATE...
&&
.AVIATION...
SHOWERS AND STORMS BEGINNING TO DEVELOP ON EAST SIDE OF PLATEAU
NEAR CROSSVILLE SO HAVE UPDATED TERMINAL FORECAST FOR CROSSVILLE
TO INCLUDE A CHANCE OF THUNDERSTORMS FOR THE NEXT SEVERAL HOURS.
LATEST RUC SHOWING UPPER LEVEL TROUGH OVER EASTERN TENNESSEE
APPROACHING PLATEAU.
BOYD
&&
.PREV DISCUSSION... /ISSUED 721 PM CDT WED JUL 17 2013/
UPDATE...FOR 00Z AVIATION FORECAST
AVIATION...
ISOLATED TO SCATTERED CONVECTION ON-GOING IN THE MID STATE AT THIS
TIME. THERE IS A PRETTY GOOD SWATH OF SHOWERS AND STORMS OVER
EASTERN TENNESSEE AND WESTERN CAROLINAS THAT MAY WORK WESTWARD
THIS EVENING AND OVERNIGHT INTO THE MID STATE. THIS ACTIVITY IS
ASSOCIATED WITH AN EASTERLY WAVE THATS BEEN PROGRESSING WESTWARD
WITH TIME. IF THIS TREND CONTINUES THIS ACTIVITY WILL REACH THE
PLATEAU AROUND 02Z-03Z AND CONTINUE WESTWARD LATE EVENING AND
OVERNIGHT. H-TRIPLE-R HI RES BRINGS THIS ACTIVITY UP TO INTERSTATE
65 BY 07Z. LOOK FOR SCATTERED CONVECTION DURING THE DAY ON
THURSDAY.
BOYD
PREV DISCUSSION... /ISSUED 541 PM CDT WED JUL 17 2013/
MESOSCALE UPDATE...
THUNDERSTORMS MOVING THROUGH GRUNDY COUNTY DROPPING RAINFALL OF
ONE TO 1.25 INCHES PER HOUR. STORMS SHOULD EXIT SHORTLY BUT WILL
HAVE TO WATCH UPSTREAM STORMS FOR TRAINING.
BOYD
PREV DISCUSSION... /ISSUED 309 PM CDT WED JUL 17 2013/
DISCUSSION...
CURRENT RADAR TRENDS INDICATE VERY ISOLATED SHOWERS ACROSS MIDDLE
TENNESSEE. VISIBLE SATELLITE IMAGERY SHOWS DIURNAL CU FIELD
DEVELOPED JUST AFTER 15Z TODAY...AND FIGURE THIS WILL BE THE TREND
OVER THE NEXT COUPLE OF DAYS BEFORE A FRONTAL BOUNDARY PUSHES DOWN
THIS WEEKEND. MODELS INDICATE A SLIGHT INCREASE IN MOISTURE FOR
THURSDAY AND FRIDAY...SO AM ANTICIPATING A CORRESPONDING SLIGHT
INCREASE IN SHOWER CHANCES THE NEXT TWO DAYS. UPSTREAM RADAR
TRENDS INDICATE A BROADER COVERAGE OF CONVECTION...AND EXPECT THIS
PATTERN TO SHIFT WESTWARD WHILE WEAKENING SOMEWHAT.
BETTER CHANCES FOR RAIN SHOWERS AND CONVECTION WILL BE THIS
WEEKEND AS FLOW SHIFTS AROUND TO THE SOUTHWEST AHEAD OF A WEAK
FRONTAL BOUNDARY THAT WILL PASS THROUGH BY SUNDAY EVENING. BEHIND
THE FRONT...THE FLOW REMAINS WESTERLY...SO EXPECT LITTLE IN THE
WAY OF RELIEF FROM THE WARM TEMPERATURES AND HUMIDITY. THE UPPER
TROUGH THAT IS EXPECTED TO SET UP OVER THE EASTERN HALF OF THE
U.S. WILL REMAIN IN PLACE THROUGH THE END OF THE FORECAST
PERIOD...WITH THE EXTENDED MODELS HINTING AT A RELIEF PERHAPS BY
NEXT WEEKEND.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
99
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1052 AM CDT TUE JUL 16 2013
.UPDATE...
MORNING FORECAST UPDATE.
&&
.DISCUSSION...
AREA RADAR ARE SHOWING AT LEAST WIDELY SCATTERED SHOWERS AND A
FEW THUNDERSTORMS PUSHING INTO THE COASTAL COUNTIES THIS MORNING.
VIS SATELLITE NOT SHOWING AS MUCH CLOUD COVER AS YESTERDAY SO
THINK MAX TEMPS IN THE UPPER 80S TO LOW 90S LOOKS ON TRACK. UPPER
LEVEL LOW NOW LOCATED OVER NEW MEX AND UPPER LEVEL RIDGE OVER OHIO
VALLEY WILL SUPPORT DEEP SE FLOW OVER THE AREA WITH DEEP TROPICAL
MOISTURE COMING INTO THE REGION ON GOES SOUNDER DATA. GIVEN
CURRENT COVERAGE HAD TO DECREASE POPS SOME BUT LEFT 60 POPS THIS
MORNING WHERE IT WILL MOST LIKELY RAIN NEXT 3 HRS BASED ON RADAR
TRENDS. LAST COUPLE OF HRRR RUNS AND 00Z/06Z WRF RUNS SHOW MORE
WIDESPREAD SCATTERED ACTIVITY DURING THE AFTERNOON AS BOUNDARY
LAYER HEATS UP. THINK 60 POPS OVER MUCH OF THE AREA WILL COVER THE
RAIN CHANCES FOR THE AFTERNOON. ACTIVITY SHOULD DISSIPATE 00-03Z
SO ADJUSTED POPS DOWN SOME FOR THE OVERNIGHT. DO EXPECT ANOTHER
ROUND OF ACTIVITY TOMORROW SO SHOULD SEE POPS INCREASE AGAIN WED
MORNING/AFTERNOON.
MAIN THREATS FROM ANY OF THE STRONGER STORMS WILL BE LOCALLY
HEAVY RAIN...LIGHTNING AND GUSTY WINDS. MOST OF THE ACTIVITY WILL
BE SHOWERS BUT AGAIN A FEW STRONG STORMS COULD OCCUR AS ATMOSPHERE
BECOMES MORE UNSTABLE WITH DAYTIME HEATING. RAIN RATES IN MOST
SHOWERS WILL BE A HALF INCH TO AN INCH AN HOUR BUT THE STRONGER
STORMS COULD PRODUCE A SOLID 1-2 INCHES VERY QUICKLY.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 91 73 91 73 92 / 60 40 50 20 20
HOUSTON (IAH) 89 74 90 75 92 / 60 40 50 20 20
GALVESTON (GLS) 87 80 90 81 90 / 60 40 60 30 30
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 7 PM CDT THIS EVENING
FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE
MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM
FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS
FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH
ISLAND TO FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...39
AVIATION/MARINE...33
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1130 PM CDT MON JUL 15 2013
.DISCUSSION...
SEE 06Z AVIATION DISCUSSION.
&&
.AVIATION...
HIGH MOISTURE LEVELS WILL PERSIST FOR THE DURATION OF THE TAF
PACKAGE. HRR AND RAP BOTH SHOW SOME DECREASE IN COVERAGE FROM
06-09Z WITH SHRA RAPIDLY INCREASING IN COVERAGE AGAIN AROUND 10Z
NEAR THE COAST DUE TO STRONG SPEED CONVERGENCE. LOW CONVECTIVE
TEMPS IN THE MID 80S SHOULD ALLOW POP-UP SHOWERS THROUGH THE DAY
TUESDAY. CAN`T REALLY PINPOINT WHEN AND WHERE SHRA WILL DEVELOP
SO WILL CARRY VCSH AND TEMPO WHEN PRECIP APPROACHES AREA AIRPORTS.
WINDS WILL BRIEFLY GUST ABOVE 15 KTS AS THE SHOWERS MOVE THROUGH.
WINDS WILL ALSO BACK FROM THE SE TO THE EAST ON TUES MORNING. 43
&&
.PREV DISCUSSION... /ISSUED 850 PM CDT MON JUL 15 2013/
DISCUSSION...
SCT SHOWERS AND ISO TSTMS CONTINUE MOVING W/NW ACROSS SE TX THIS
EVENING IN A MOIST AND AN UNSTABLE ATMOSPHERE. BELIEVE SCT
CONVECTION WILL CONTINUE THROUGH THE NIGHT WITH SE AREAS BECOMING
MORE ACTIVE DURING THE EARLY MORNING HOURS THAN THE FAR INLAND
AREAS. NO BIG CHGS TO THE FORECAST...JUST SOME SMALL ADJUSTMENTS
TO EVE POPS AND CLOUD COVER. 33
MARINE...
WILL BE ADDING A CAUTION STATEMENT TO THE OFFSHORE ZONES FOR 15
TO 20 KTS WINDS.
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 72 90 73 91 73 / 30 60 40 50 20
HOUSTON (IAH) 74 90 74 90 75 / 40 60 40 50 20
GALVESTON (GLS) 81 88 80 88 81 / 50 60 40 50 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 5 AM CDT TUESDAY FOR
THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA
SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM FREEPORT TO THE
MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND
TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH ISLAND TO
FREEPORT OUT 20 NM.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
301 PM CDT TUE JUL 16 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 300 PM CDT TUE JUL 16 2013
CURRENTLY AS OF 20Z...
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED AN UPPER LOW
JUST OFF THE NORTHERN CALIFORNIA COAST...TROUGHING OVER SASKATCHEWAN
AND MANITOBA...AND A 600 DAM SUBTROPICAL HIGH NEAR SOUTH BEND
INDIANA. 500MB HEIGHTS ARE 2-3 STANDARD DEVIATIONS ABOVE NORMAL FROM
THE FORECAST AREA EASTWARD INTO NEW ENGLAND. DESPITE THE HIGH 500MB
HEIGHTS...850MB TEMPS AT 12Z WERE GENERALLY 17-18C PER SOUNDING
DATA. PLENTY OF SUNSHINE HAS ALLOWED FULL MIXING TO 850MB...YIELDING
TEMPERATURES IN THE UPPER 80S TO MID 90S. ACCOMPANYING THE
SUBTROPICAL HIGH IS PLENTY OF DEEP MOISTURE...NOTED BY PRECIPITABLE
WATER VALUES OF 1.75 TO 2 INCHES FROM EASTERN OKLAHOMA INTO THE
FORECAST AREA. ITS WORTH NOTING THAT THE 12Z GRB SOUNDING
PRECIPITABLE WATER VALUES OF 2.07 INCHES IS AT THE 99TH PERCENTILE.
THIS DEEP MOISTURE IS ALSO REFLECTED AT THE SURFACE WITH DEWPOINTS
IN THE UPPER 60S/LOWER 70S...A LITTLE LOWER THAN AT 15Z DUE TO
MIXING AND DRIER SOILS. PLENTY OF CUMULUS HAS DEVELOPED IN THIS
MOIST AIRMASS. DESPITE HIGHER 500MB HEIGHTS TODAY COMPARED TO
YESTERDAY...THE HIGHER PRECIPITABLE WATER VALUES COMPARED TO MODEL
FORECASTS FROM YESTERDAY AND DAYTIME INSTABILITY HAS LED TO SOME
SHOWER DEVELOPMENT. TO THE NORTHWEST...A COLD FRONTAL BOUNDARY
ACCOMPANYING THE SOUTH CENTRAL CANADA TROUGH STRETCHED FROM
NORTHWEST ONTARIO BACK INTO THE BLACK HILLS OF SOUTH DAKOTA.
SYNOPTIC OVERVIEW...
THE SUBTROPICAL HIGH LOOKS TO SLOWLY DRIFT SOUTH DURING THE NEXT 24
HOURS IN RESPONSE TO THE SOUTH CENTRAL CANADA TROUGH PUSHING EAST
AND FLATTENING THE RIDGE. AS THIS OCCURS...THE COLD FRONTAL BOUNDARY
LOOKS TO LAY UP EAST TO WEST FROM NEAR THE NORTH DAKOTA/SOUTH DAKOTA
STATE LINE INTO UPPER MICHIGAN.
TONIGHT...
DIURNAL CUMULUS CLOUDS AS WELL AS ANY SHOWER ACTIVITY WILL DISSIPATE
THIS EVENING WITH LOSS OF HEATING...AND THEN THE REST OF NIGHT
SHOULD BE MOSTLY CLEAR. ANY POTENTIAL FOR ELEVATED CONVECTION LOOKS
TO OCCUR WELL OFF TO OUR NORTH ALONG THE FRONTAL BOUNDARY. A WARM
AND MUGGY NIGHT IS LIKELY AS DEWPOINTS JUMP BACK UP WITH LOSS OF
MIXING.
WEDNESDAY...
WITH A SOUTHWEST SURFACE FLOW AND THE COLD FRONTAL BOUNDARY STILL
OFF TO OUR NORTH...ANTICIPATING ANOTHER DRY DAY. ADDITIONALLY...
16.12Z NAM/GFS PRECIPITABLE WATER FORECASTS SUGGEST SLIGHTLY DRIER
VALUES IN THE 1.5 TO 1.8 INCH RANGE. THESE DRIER PRECIPITABLE WATER
VALUES SUPPORT A DRIER FORECAST...IN AGREEMENT TOO WITH THE 16.12Z
NAM AND HIRES-ARW. SHOULD SEE DEWPOINTS MIX DOWN A LITTLE MORE DUE
TO THOSE LOWER VALUES AND SOILS CONTINUING TO DRY OUT. 850MB TEMPS
ARE PROGGED SLIGHTLY WARMER THAN TODAY...18-19C...SO WE SHOULD BE
ABLE TO TACK ON 1-2F FOR HIGHS COMPARED TO TODAY. WITH THE
DEWPOINTS MIXING OUT...ANTICIPATING HEAT INDICES IN THE 95-102F
RANGE FOR A MAX.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 300 PM CDT TUE JUL 16 2013
SYNOPTIC OVERVIEW...
MODELS REMAIN IN GOOD AGREEMENT SHOWING THE SUBTROPICAL HIGH
CONTINUING TO GET SUPPRESSED TO THE SOUTH...IN RESPONSE TO TROUGHING
EVENTUALLY DEVELOPING OVER THE WESTERN GREAT LAKES BY SATURDAY. THIS
TROUGHING IS A COMBINATION OF TWO FEATURES:
1. THE CURRENT UPPER LOW OFF THE NORTHERN CALIFORNIA COAST DROPPING
THROUGH THE AREA AS A SHORTWAVE TROUGH LATE FRIDAY.
2. A POTENT TROUGH DROPPING THROUGH CENTRAL CANADA ON FRIDAY AND
POSSIBLY PHASING WITH THE AFOREMENTIONED SHORTWAVE TROUGH.
THE FORECAST AREA GENERALLY LOOKS TO STAY IN A NORTHWEST FLOW
HEADING INTO EARLY NEXT WEEK ACCORDING TO THE 16.12Z GFS/ECMWF.
HAZARDS...
EARLIER TODAY ISSUED A HEAT ADVISORY THROUGH FRIDAY. PART OF THE
UPGRADE WAS RELATED TO HOW QUICKLY WE WARMED THIS MORNING...
DEWPOINTS TAKING LONGER TO MIX OUT THAN EXPECTED...SLIGHTLY WARMER
TEMPERATURES THAN PREVIOUSLY FORECAST FOR WEDNESDAY THROUGH
THURSDAY...AND CONCERN FRIDAY WILL BE WARMER TOO. HEAT INDICES
GENERALLY SHOULD RANGE BETWEEN 95-100 EACH DAY ACROSS THE ENTIRE
FORECAST AREA...UNTIL THE FRONTAL PASSAGE FRIDAY...WITH VALLEY
LOCATIONS LIKELY AT OR ABOVE 100. NORMALLY 100 DEGREES IS THE
CRITERIA FOR HEAT ADVISORY...BUT IF A LONG DURATION EVENT OF 4 OR
MORE DAYS OCCUR WITH SLIGHTLY BELOW 100 DEGREE READINGS...AN
ADVISORY CAN BE ISSUED. ONLY TAYLOR COUNTY IS NOT IN A HEAT ADVISORY
BECAUSE OF CONVECTION CONCERNS WED NIGHT THROUGH FRIDAY.
CANNOT RULE OUT SOME SEVERE WEATHER ACROSS TAYLOR COUNTY THURSDAY
NIGHT OR POSSIBLY ON THE FRONT ON FRIDAY...BUT CONFIDENCE OF
PRECIPITATION IS LOWER AS DISCUSSED IN THE DAILY DETAILS BELOW.
DAILY DETAILS...
WEDNESDAY NIGHT THROUGH FRIDAY...
CONFIDENCE CONTINUES TO DECREASE OF PRECIPITATION AFFECTING THE
FORECAST AREA. THERE ARE NUMEROUS ISSUES THAT POINT TO A DRIER
FORECAST MORE LIKELY:
1. LOOKING AT ELEVATED CONVECTION POTENTIAL WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT...THE 16.12Z NAM/ECMWF POINT THE NOSE OF THE 850MB
MOISTURE TRANSPORT NORTH OF THE FORECAST AREA...AND BY THURSDAY
NIGHT EVEN NORTHEAST OF LAKE SUPERIOR.
2. NOT CONNECTED TO A DRIER FORECAST MORE LIKELY...BUT THE GFS IS
PRODUCING WAY TOO MUCH PRECIPITATION IN THIS VERY WARM AND HUMID
ENVIRONMENT. ITS ALMOST LIKE IT CANNOT THE INSTABILITY. THIS
PRECIPITATION FEEDS BACK INTO OTHER FIELDS LIKE 850MB MOISTURE
TRANSPORT...MAKING THAT UNUSABLE.
3. AS THE FRONT AND SHORTWAVE APPROACH FRIDAY...THERE IS A DEFINITE
WARM SURGE AT 800MB COMING ACROSS THE AREA ON TOP OF THE FRONT. THIS
WARM SURGE COULD EFFECTIVELY CAP CONVECTION...BRINGING THE FRONT
THROUGH DRY. THE 16.12Z NAM/ECMWF DEPICT ISOLATED/SCATTERED
DEVELOPMENT AT MOST.
4. FRONTAL TIMING IS A BIG ISSUE...WITH MODELS SUGGESTING THE COLD
FRONT IS INTO LA CROSSE AT 18Z FRIDAY. DRY CONDITIONS ARE LIKELY
ONCE THE FRONT PASSES.
GIVEN ALL OF THE ABOVE ISSUES...HAVE SHIFTED PRECIPITATION CHANCES
FARTHER NORTH WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...AND KNOCKED
PRECIPITATION CHANCES DOWN FOR FRIDAY. PRECIPITATION STILL SEEMS
LIKELY TO IMPACT TAYLOR AND POSSIBLY CLARK COUNTIES DURING THIS TIME
FRAME...THOUGH.
TEMPERATURES ARE TRICKY TOO. GIVEN HOW WARM WE GOT TODAY AND THE
AIRMASS CONTINUING TO MODIFY...THINKING EACH DAY SHOULD BE JUST
SLIGHTLY WARMER THAN THE PREVIOUS. RAISED HIGHS THURSDAY AND
FRIDAY...AND DEPENDING ON FRONTAL TIMING FRIDAY COULD BE THE WARMEST
AS THAT WARM SURGE OF AIR MENTIONED IN POINT 3 ABOVE COMES IN.
FRIDAY NIGHT THROUGH TUESDAY...
HIGH PRESSURE LOOKS TO BUILD INTO THE FORECAST AREA FOR FRIDAY NIGHT
THROUGH SATURDAY NIGHT BEHIND THE FRONT...PROVIDING COOLER AND DRIER
CONDITIONS. STILL MAINTAINED A 20 PERCENT CHANCE IN THE EVENING IN
THE SOUTHEASTERN PORTION OF THE FORECAST AREA IN THE EVENT
CONVECTION/FRONT IS SLOWER. AS WE HEAD INTO SUNDAY AND THROUGH EARLY
NEXT WEEK...FORECAST BECOMES A BIT MORE PROBLEMATIC. MODELS ARE
SHOWING A VARIETY OF SHORTWAVES DROPPING THROUGH THE NORTHWEST
FLOW...WHILE AT THE SAME TIME 500MB HEIGHTS ARE RISING WITH WARM
ADVECTION IN THE LOWER LEVELS. THIS BECOMES A FAVORABLE PATTERN FOR
MULTIPLE ROUNDS OF CONVECTION. HAVE 20 PERCENT CHANCES IN THE
FORECAST FOR SUNDAY OVER WESTERN PORTIONS OF THE FORECAST
AREA...WHICH THEN EXPAND EAST AND BEGIN TO INCREASE ACROSS THE REST
OF THE AREA FOR SUNDAY NIGHT THROUGH TUESDAY. WE MAY HAVE TO WATCH
TEMPERATURES AGAIN AS WE APPROACH TUESDAY AS WELL...WITH THE
16.00Z/16.12Z ECMWF BRINGING 850MB TEMPS UP TO 24C WEST OF THE MS
RIVER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1200 PM CDT TUE JUL 16 2013
OVERALL VFR CONDITIONS EXPECTED THROUGH WEDNESDAY AFTERNOON. WITH
THE VERY HUMID AIRMASS IN PLACE...COULD SEE SOME LIGHT FOG
DEVELOPING OVERNIGHT BUT NOT EXPECTING ANYTHING LESS THAN 5-6SM.
OTHERWISE...DAYTIME HEATING/INSTABILITY WILL LEAD TO EXPANSIVE
CUMULUS FIELD. CANNOT RULE OUT A STRAY SHRA/TS...BUT WITH NO REAL
FORCING MECHANISM...NOT CONFIDENT ENOUGH TO PUT IN THE BODY OF THE
KRST/KLSE TAF RIGHT NOW.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY UNTIL 7 PM CDT FRIDAY FOR WIZ029-032>034-041>044-
053>055-061.
MN...HEAT ADVISORY UNTIL 7 PM CDT FRIDAY FOR MNZ079-086>088-094>096.
IA...HEAT ADVISORY UNTIL 7 PM CDT FRIDAY FOR IAZ008>011-018-019-029-
030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...DAS
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
240 PM CDT TUE JUL 16 2013
.TONIGHT AND WEDNESDAY - CONFIDENCE...MEDIUM TO HIGH
HOISTED HEAT ADVISORY WITH LIKELIHOOD OF DAYTIME HEAT INDICES
REACHING 95 TO 100 THROUGH FRIDAY. WARM AND TROPICAL NIGHT WITH ANY
LINGERING CU/ISOLD SHRA OR TSRA DISSIPATING THIS EVENING. 6000 METER
HEIGHT CONTOUR INTO SE WI PER RUC ANALYSIS. GREATER COVERAGE OF TSRA
ON NW PERIPHERY OF THE RIDGE. STILL THINK THERE IS POTENTIAL FOR
ISOLATED DEVELOPMENT ALONG THE LAKE BREEZE BOUNDARY INTO THE EVENING
HOURS. 925 TEMPS AROUND 25-26C WEDNESDAY SO UPPER 80S/LOWER 90S LOOK
GOOD WITH TROPICAL DEW POINTS IN THE MID 70S. WILL CARRY A VERY
SMALL POP FOR THE AFTERNOON HOURS TO ACKNOWLEDGE A BLEND OF ALL THE
MODEL SOLUTIONS. A TRIGGER MAY BE HARD TO COME BY.
.WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...FORECAST CONFIDENCE IS
MEDIUM TO HIGH.
THE BIG SURFACE HIGH PRESSURE SYSTEM WILL BE DRIFTING TO THE
SOUTH WITH TIME. BY THURSDAY WE/LL START TO GET INTO A BETTER
SOUTHWEST GRADIENT FLOW BETWEEN THE HIGH TO THE SOUTH AND THE
APPROACHING COLD FRONT/TROUGH TO THE NORTHWEST. WILL ONLY CARRY
SOME SMALL POPS ACROSS MY FAR NORTH FOR ANYTHING THAT MAY SNEAK IN
WITH THE RING OF FIRE GETTING CLOSER. LOOK FOR HIGHS ON THURSDAY
AROUND 90 MOST PLACES WITH HEAT INDICES APPROACHING OR REACHING
100 IN SOME SPOTS.
.FRIDAY AND FRIDAY NIGHT...FORECAST CONFIDENCE IS MEDIUM TO HIGH.
THE HEAT WILL REMAIN IN PLACE WITH FRIDAY NOW LOOKING A TOUCH
WARMER. 925MB TEMPS ON FRIDAY WILL BE PUSHING 26C IN A NARROW
WEDGE AHEAD OF THE APPROACHING FRONT...WHICH IS WARMER THAN
PREVIOUS RUNS. CLOUDS WILL BE INCREASING...SO WE WON/T REALIZE
THAT FULL POTENTIAL OF HEAT IF WE HAD GOOD MIXING WITH SUNSHINE.
HEAT INDICES AGAIN 95 TO 98. THE TIMING OF THE FRONT HASN/T CHANGED
MUCH WITH THE NEW RUNS...STILL REACHING THE WI/IL BORDER BY OR
SHORTLY AFTER 00Z SAT.
IT APPEARS THE BEST CHANCE FOR THUNDERSTORMS...AND SOME MAY BE
SEVERE...WITH THE FRONT WILL BE ACROSS THE EASTERN FORECAST AREA.
THE ORIENTATION OF THE ADVANCING FRONT WITH THE LAKE SHORE WILL
RESULT IN A MOVING TRIPLE POINT OF CONVERGENCE WHERE THE COLD
FRONT INTERSECTS THE STATIONARY COOL LAKE BNDRY. THE LAKE WILL
ESSENTIALLY BE ANOTHER LLV COLD FRONT WITH WARM ADVECTION/LIFT
OCCURRING JUST AHEAD OF THE FRONT...OVER THE COOLER DOME OF THE
LAKE. UPWELLING WITH THE INCREASING SOUTHWEST WINDS MAY HELP TO
ENHANCE THE BAROCLINIC ZONE. THE CIPS ANALOGS SHOW THE EAST WITH
THE BIGGEST THREAT FOR SEVERE WEATHER...MAINLY WIND AND HAIL. BACK
TO THE WEST TOWARD MADISON...THERE IS SOME LOW LEVEL CAPPING THAT
MAY BE HARD TO BUST...SO THE SEVERE THREAT DIMINISHES AS YOU GET
TO MADISON AND POINTS WEST.
THE RAIN SHOULD BE EXITING QUICKLY DURING THE EVENING WITH DRY
CONDITIONS RETURNING AFTER MIDNIGHT.
.SATURDAY AND SUNDAY...FORECAST CONFIDENCE IS HIGH.
A MUCH COOLER AND DRIER AIRMASS RETURNS FOR THE WEEKEND BRINGING
VERY PLEASANT TEMPERATURES. LOOK FOR HIGHS IN THE 70S AND NO RAIN.
.MONDAY AND TUESDAY...FORECAST CONFIDENCE IS MEDIUM.
WARM ADVECTION KICKS IN FOR MONDAY NIGHT INTO MONDAY AHEAD OF AN
APPROACHING LOW PRESSURE FROM THE NORTHWEST. THE WAA AND LOW
PRESSURE WILL BRING ANOTHER CHANCE FOR SHOWERS AND STORMS...ALONG
WITH SOME WARMER TEMPS.
&&
.AVIATION/00Z TAFS/...BKN VFR CU FIELD WILL DISSIPATE DIURNALLY ONCE
AGAIN THIS EVENING. VRY ISOLD TSRA THREAT INTO THE EARLY EVENING.
WITH LIGHT WIND REGIME PATCHY FOG DEVELOPMENT LOOKS REASONABLE
TONIGHT AS SUGGESTED BY MOS. LIKELY TO SEE MORE CU WEDNESDAY WITH
POTENTIAL FOR AN ISOLATED TSRA. ALTHOUGH MODEL COVERAGE AND
CONSENSUS NOT TOO CONVINCING.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY UNTIL 7 PM CDT FRIDAY FOR WIZ046-047-056-057-062-
063-067-068.
LM...NONE.
&&
$$
TONIGHT/WEDNESDAY AND AVIATION/MARINE...COLLAR
WEDNESDAY NIGHT THROUGH TUESDAY...DAVIS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1152 PM CDT MON JUL 15 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 249 PM CDT MON JUL 15 2013
CURRENTLY AS OF 19Z...
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED TROUGHING OVER
SOUTHWEST CANADA...AN UPPER LOW OVER THE TEXAS PANHANDLE
RETROGRADING WESTWARD...AND A NEAR 600 DAM HIGH NEAR TOLEDO OHIO
ALSO RETROGRADING WESTWARD. STANDARD DEVIATIONS AGAIN WITH THIS HIGH
ARE RUNNING 2.5 ABOVE NORMAL. BETWEEN THE UPPER LOW AND SUBTROPICAL
HIGH...DEEP LAYER SOUTH TO SOUTHEAST WINDS ARE ADVECTING HIGHER
PRECIPITABLE WATER VALUES TOWARDS THE FORECAST AREA. 12Z DVN AND ILX
REPORTED VALUES OF 1.89 AND 2.04 INCHES RESPECTIVELY. HIGHER SURFACE
DEWPOINTS IN THE LOW 70S HAVE ACCOMPANIED THIS DEEP MOISTURE. WITH
TEMPERATURES THAT HAVE CLIMBED INTO THE UPPER 80S/LOW 90S...
RESULTING IN MLCAPE VALUES OF 500-1000 J/KG...ISOLATED SHOWERS HAVE
FORMED. NO LIGHTNING YET...WHICH MAY BE A RESULT OF THE SHALLOW
NATURE OF THE SHOWERS AND DEEP WARM CLOUD DEPTHS PREVENTING ICE
PRODUCTION. DESPITE THE HIGH 500MB HEIGHTS OVER THE FORECAST
AREA...ON THE ORDER OF 594-597 DAM...850MB TEMPS ARE ONLY 16-17C.
THE REASON THESE ARE COOL COMPARED TO THE 500MB HEIGHT IS A RESULT
OF THE SUBTROPICAL HIGH BEING OF ATLANTIC OCEAN ORIGIN. HAD IT COME
OUT OF THE WESTERN U.S....THE 850MB TEMPS WOULD BE A LOT HIGHER.
SYNOPTIC OVERVIEW...
MODELS CONTINUE TO SHOW THE STRONG SUBTROPICAL HIGH DRIFTING
WESTWARD THROUGH TUESDAY...REACHING NEAR GARY INDIANA BY 00Z
WEDNESDAY. THUS...500MB HEIGHTS WILL CONTINUE TO RISE OVER THE
FORECAST AREA...IMPLYING INCREASING MID-LEVEL SUBSIDENCE.
FOR TONIGHT...
ANY AFTERNOON CONVECTION THAT IS SPREADING NORTHWARD...ACCOMPANYING
THE HIGHER PRECIPITABLE WATER...WILL DIMINISH BY 03Z THIS EVENING
WITH LOSS OF HEATING SINCE IT IS HIGHLY DIURNALLY DRIVEN. THE REST
OF THE NIGHT LOOKS DRY WITH ANY FORCING FOR NOCTURNAL CONVECTION
WELL NORTH OF THE FORECAST AREA.
ON TUESDAY...
THE BATTLE CONTINUES OF WHETHER OR NOT TO NEED A MENTION OF SHOWERS
AND THUNDERSTORMS IN THE AFTERNOON. MODELS WERE A LITTLE HYPERACTIVE
WITH DIURNAL CONVECTION TODAY...ESPECIALLY THE 15.12Z NAM SHOWING
PRECIP ACROSS ALL OF ILLINOIS BY 15Z AND THERE WAS NONE IN REALITY.
ALL MODELS ARE IN AGREEMENT OF MUCH LESS QPF...AND THE 15.12Z NAM
CONTINUES TO SHOW A DRY FORECAST FOR THE FORECAST AREA. THERE ARE
OTHER NEGATIVES TOO FOR CONVECTION...BEING CLOSER TO THE SUBTROPICAL
HIGH...AND 0.25-0.5 INCH DRYING OF PRECIPITABLE WATER VALUES
ORIGINATING FROM EASTERN KY/TN THIS MORNING. SEEING THE DRY FORECAST
FROM THE NAM...THE 15.12Z CANADIAN WHICH DID A GOOD JOB WITH PRECIP
TODAY AND IS DRY FOR TUESDAY...ALONG WITH OTHER MODELS SHOWING VERY
LITTLE IF ANY QPF...WENT BACK TO A DRY FORECAST. 850MB TEMPS ARE 2C
HIGHER TOMORROW...BETWEEN 18-19C...SO WE SHOULD SEE ABOUT A SIMILAR
INCREASE IN HIGH TEMPERATURES INTO UPPER 80S/LOW 90S. DEWPOINTS UP
IN THE UPPER 60S/LOW 70S AND THE FORECAST HIGH TEMPERATURES WILL
LIKELY LEAD TO PLENTY OF CUMULUS...BUT MORE IMPORTANTLY MAKE IT FEEL
MUGGY. HEAT INDICES ARE STILL FORECAST TO TOP OUT IN THE 95-100
RANGE.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 249 PM CDT MON JUL 15 2013
SYNOPTIC OVERVIEW...
MODELS REMAIN CONSISTENT IN THE STRONG SUBTROPICAL HIGH RETROGRADING
ACTUALLY SOUTHWESTWARD THROUGH THE REST OF THE WEEK. THIS IS IN
RESPONSE TO FIRST THE TROUGH IN SOUTHWEST CANADA MARCHING
EAST-NORTHEAST AND FLATTENING THE RIDGE...AND FINALLY AN UPPER LOW
CURRENTLY OFF THE COAST OF SAN FRANSISCO DROPPING SOUTHEAST THROUGH
THE FORECAST AREA AS A SHORTWAVE TROUGH. BY SATURDAY WE SHOULD BE
LOOKING AT TROUGHING OVER THE WESTERN GREAT LAKES VERSUS THE CURRENT
RIDGING. HEADING INTO SUNDAY AND MONDAY...INDICATIONS ARE THAT A
MORE POTENT SHORTWAVE TROUGH WILL BE APPROACHING THE AREA IN THE
NORTHWEST FLOW.
HAZARDS...
HEAT INDICES REMAIN THE BIG CONCERN. TUESDAY THROUGH THURSDAY LOOK
SOLID TO HAVE AFTERNOON HEAT INDICES BETWEEN 95-100...ESPECIALLY IN
THE VALLEYS. HEAT ADVISORY CRITERIA REQUIRES 100 OR GREATER FOR 1
DAY OR GREATER THAN 95 FOR 4 OR MORE DAYS. THE MORE LIKELY OF THE
TWO OPTIONS TO HIT WOULD BE DURATION. HEAT INDICES ONLY TOPPED OUT
IN THE UPPER 80S TO MID 90S TODAY...SO THAT MEANS FRIDAY WOULD NEED
95 OR GREATER. WITH CONCERN OF THE FRONT AND CONVECTION COMING
THROUGH FRIDAY...HAVE REFRAINED AT THIS TIME FROM ISSUING A HEAT
ADVISORY. HOWEVER...WE WILL ISSUE A SPECIAL WEATHER STATEMENT TO
DISCUSS THE HEAT. NOTE THAT THIS TIME PERIOD OF 15TH THROUGH 18TH
OF JULY IS COMMONLY THE TIME TO GET HEAT.
THERE IS A POSSIBILITY OF SEVERE WEATHER TOO IN THE THURSDAY THROUGH
FRIDAY TIME PERIOD. THURSDAY/THURSDAY NIGHT WOULD BE MORE TO THE
NORTH...PERHAPS JUST TAYLOR/CLARK COUNTIES AS ALSO SHOWN IN THE SPC
DAY 4-8 OUTLOOK. FRIDAY IT ALL DEPENDS ON THE FRONTAL TIMING.
ADDITIONALLY...THE BEST 0-6KM SHEAR IS BEHIND THE FRONT...WITH ONLY
30-35 KT ON THE FRONT. SO IT WOULD SEEM THAT OVERALL ANY SEVERE
WEATHER WOULD BE ISOLATED WITH DAMAGING WINDS AND HEAVY RAIN THE
MAIN HAZARDS.
DAILY DETAILS...
TUESDAY NIGHT AND WEDNESDAY...
A COLD FRONT ACCOMPANYING THE SOUTHWEST CANADA TROUGH IS PROGGED TO
DROP INTO NORTHERN MN BY 12Z WED AND THEN LAY UP BETWEEN ST CLOUD MN
AND UPPER MI LATE WEDNESDAY. ENVISIONING CONVECTION ON THIS
BOUNDARY...DUE TO PLENTIFUL MOISTURE AND INSTABILITY AROUND IT...
ALONG WITH LAKE BREEZE ENHANCED CONVERGENCE. GIVEN ITS LOCATION...
ANTICIPATING ANY CONVECTION TO STAY UP TO THE NORTH THROUGH
WEDNESDAY. WILL NEED TO MONITOR TAYLOR COUNTY FOR A NEED FOR SOME
CHANCES OF PRECIPITATION IN LATER FORECASTS SHOULD THE BOUNDARY DROP
FARTHER SOUTH. OTHERWISE...PRECIPITABLE WATER VALUES ARE PROGGED TO
HOLD STEADY OR EVEN FALL A LITTLE MORE COMPARED TO TUESDAY...SO NOT
ANTICIPATING ANY DIURNAL CONVECTION. WITH CONTINUED AIRMASS
MODIFICATION OF THE SUBTROPICAL HIGH...850MB TEMPS CLIMB ABOUT
ANOTHER 1C...WHICH WITH PLENTY OF SUN SHOULD YIELD ANOTHER DAY OF
HIGHS IN THE UPPER 80S/LOW 90S.
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...
THIS PERIOD APPEARS A BIT MORE MUDDLED / LESS CONFIDENCE / THAN
BEFORE. WITH A ZONAL UPPER FLOW PATTERN THROUGH THURSDAY...THE COLD
FRONT SITUATED UP TO OUR NORTH APPEARS LIKELY TO STAY IN PLACE. IN
FACT...ON THURSDAY NIGHT WHEN THE SHORTWAVE TROUGH DROPS INTO THE
DAKOTAS...THE FRONT COULD EVEN GET PROPELLED NORTHWARD. 15.12Z
ECMWF/GFS/NAM/UKMET/CANADIAN ALL DEPICT THE NOSE/GRADIENT OF THE
850MB MOISTURE TRANSPORT STAYING FOCUSED FROM NORTHERN MN INTO
NORTHERN WI/UPPER MI AND LOWER MI FROM WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT. FIGURE CONVECTION WOULD EITHER BE TIED TO THE FRONT
OR NOSE OF THE MOISTURE TRANSPORT...WHICH BOTH SUGGEST NORTH OF THE
FORECAST AREA. CORFIDI VECTORS ARE FAIRLY LIGHT TOO IN TERMS OF
SPEEDS WITH DIRECTIONS MAINLY WEST OR WEST-NORTHWEST...SO IF AN MCS
FORMS IT COULD END UP STAYING NORTH OF THE AREA AS WELL. GIVEN ALL
OF THIS...HAVE DECIDED TO SHIFT ALL OF THE PRECIPITATION CHANCES
NORTHWARD...WHICH MEANS A REDUCTION ACROSS THE BOARD. WOULD NOT BE
SURPRISED IF ALL STORMS DURING THIS PERIOD STAY NORTH OF HIGHWAY 29.
TEMPERATURES THURSDAY LOOK SIMILAR TO TUESDAY AND WEDNESDAY WITH
850MB TEMPS OF 18-20C.
FRIDAY THROUGH MONDAY...
GOOD AGREEMENT REMAINS ABOUT THE COLD FRONT COMING THROUGH THE AREA
ON FRIDAY...AHEAD OF THE SHORTWAVE TROUGH. HAVE SOME CONCERN THAT
THIS FRONT COULD COME THROUGH DRY SEEING THE 15.00Z ECMWF. THREE
NEGATIVES WITH THIS FRONT FOR CONVECTION IS THE POSITIVELY TITLED
NATURE OF THE SHORTWAVE...WEAK CONVERGENCE AND THAT THE TIMING MAY
BE MESSED UP. FOR NOW LEFT A MODEL CONSENSUS 20-40 PERCENT CHANCES
IN THE FORECAST INTO FRIDAY EVENING. HIGH PRESSURE IS STILL
INDICATED TO BUILD INTO THE AREA FOR THE WEEKEND. HOWEVER...BEING
UNDER UPPER TROUGHING YIELDS CONCERNS FOR SHORTWAVES COMING THROUGH
AT PEAK HEATING AND INITIATING CONVECTION. THE 15.00Z ECMWF HINTED
AT THIS FOR SATURDAY...BUT THE 15.12Z RUN IS NOW DRY. WITH A DRY GFS
FORECAST...HAVE KEPT SATURDAY INTO SATURDAY NIGHT DRY. MUCH OF
SUNDAY MAY BE DRY TOO...THOUGH THERE ARE INDICATIONS FROM THE 15.12Z
ECMWF OF A SHORTWAVE MOVING INTO MN BRINGING CONVECTION TO LOCATIONS
MAINLY WEST OF THE MS RIVER. THUS...HAD TO KEEP SOME LOW CHANCES
THERE. ADDITIONAL CHANCES IN THE 20-40 RANGE ARE FORECAST INTO
MONDAY ASSOCIATED WITH THE MORE POTENT SHORTWAVE. TIMING IS STILL
YET TO BE DETERMINED ON THIS SHORTWAVE.
&&
.AVIATION...THROUGH 06Z WEDNESDAY
1152 PM CDT MON JUL 15 2013
AREA DIRECTLY UNDER HIGH PRESSURE WITH WEAK FLOW. EXPECTING A FEW
MID CLOUDS THROUGH THE NIGHT...AND WITH AMPLE LOW LEVEL MOISTURE
AND WEAK FLOW ANTICIPATING SOME LIGHT MIST/FOG FOR A FEW SPOTS.
PERHAPS A LITTLE BETTER CHANCE FOR A VISIBILITY RESTRICTION
TONIGHT AT KRST DUE TO THE QUARTER-INCH OF RAIN THEY PICKED UP
RIGHT AROUND SUNSET. STILL ONLY MVFR ANTICIPATED...WHICH SHOULD
QUICKLY DISSIPATE AFTER SUNRISE. VFR CONDITIONS WILL PREVAIL
THROUGH THE DAY TUESDAY. REALLY NOT MUCH SUPPORT FOR ANYTHING MORE
THAN SOME CUMULUS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...MW
AREA FORECAST DISCUSSION
NWS ALBANY NY
135 AM EDT THU JUL 18 2013
.SYNOPSIS...
HIGH PRESSURE AT ALL LEVELS OF THE ATMOSPHERE...WILL RECEDE FROM
THE MIDWEST TO THE ATLANTIC SEABOARD BY FRIDAY. A WEAK BOUNDARY WILL
DRIFT INTO AND OUT THE SAINT LAWRENCE TONIGHT AND
THURSDAY...TRIGGERING SCATTERED THUNDERSTORMS. OTHERWISE THE HEAT
AND HUMIDITY WILL PERSIST INTO UGH SATURDAY. A STRONG COLD FRONT
WILL PUSH THROUGH THE REGION SATURDAY...TRIGGERING THUNDERSTORMS AND
USHERING IN MORE A MORE SEASONABLE AIR MASS INTO OUR REGION TO START
THE NEW WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 1230 AM EDT...RADARS STILL INDICATING WIDELY SCATTERED SHOWER
ACTIVITY ACROSS THE ADIRONDACKS...EASTWARD INTO SOUTHERN VERMONT.
THESE APPEARED TO BE TIED INTO A WEAK BOUNDARY JUST TO NORTH OF THIS
REGION. INTERESTING THE EXPERIMENTAL HRRR HAS INDICATED A BROKEN
LINE OF SHOWERS AND POSSIBLY THUNDERSTORMS WORKING SOUTH THROUGH THE
CAPITAL REGION AND EVEN POINTS SOUTH OVERNIGHT.
WHILE THIS SCENARIO CANNOT BE RULED OUT...WE LEAN AGAINST IT SINCE
OUR RAOB INDICATED OUR MID LEVELS REMAINED CAPPED (VERY WARM
TEMPERATURES AROUND +10C AROUND 10,000 FEET) WHICH HAS BEEN ABLE TO
SUPPRESS CONVECTION THUS FAR. ALSO...WE HAVE LOST THE HEATING OF THE
DAY AND THE FRONT SHOULD STAY NORTH. THERE WAS ONE INTERESTING
FEATURE ON THE H20 VAPOR LOOP...A DISTINCT DRY PUNCH WELL TO OUR
NORTH WHICH COULD ALSO BE CONTRIBUTING TO THE SHOWER ACTIVITY. THIS
FEATURE SHOULD ALSO STAY TO THE NORTH.
WE DID EXTENT ISOLATED COVERAGE OF SHOWERS (AND SLIGHT CHANCE OF
THUNDERSTORMS) SOUTH TO ABOUT SARATOGA SPRINGS FOR A COUPLE OF
HOURS...WHILE KEEPING AREAS FROM THE CAPITAL DISTRICT SOUTHWARD DRY
(POPS LESS THAN 15 PERCENT).
THIS LEAVES US WITH AN OPPRESSIVE NIGHT. TEMPERATURES WERE STILL
OVER 80S IN THE CAPITAL DISTRICT...AND CLOSE TO 80 ACROSS MOST OTHER
AREAS. DEWPOINTS WERE AROUND 70. AND NOW WE ALSO HAVE SOME HAZE TON
CONTEND WITH.
THERE WAS STILL A LITTLE BREEZE OUT OF THE WEST WHICH COULD KEEP UP
IN SOME AREAS ALL NIGHT LONG.
FOR ALL THE ABOVE REASONS...RAISED TEMPERATURES A COUPLE DEGREES
ACROSS MANY AREAS. THIS WOULD MEAN OVERNIGHT LOWS WOULD ONLY FALL
TO ABOUT THE MID 70S FROM ALBANY SOUTHWARD...CLOSER TO 70 IN
OUTLYING AREAS. THESE VALUES WILL AVERAGE MORE THAN 10 DEGREES ABOVE
NORMAL FOR THE TIME OF YEAR.
THURSDAY...THE CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE ON THE
INCREASE DURING THE AFTERNOON. THE UPPER LEVEL HIGH PRESSURE WILL BE
SUPPRESSED TO THE SOUTH. THIS WILL CHANGE OUR FLOW TO ZONAL FLOW.
THIS COULD ALLOW FOR A DISTURBANCE OR TWO EMBEDDED IN THE INCREASING
FLOW TO MOVE THROUGH AND PRODUCE SCATTERED CONVECTION MAINLY DURING
THE AFTERNOON AND EVENING. MODELS ARE SHOWING DECENT CAPE ACROSS THE
REGION FROM 1000 J/KG TO 2500 J/KG.
TEMPERATURES ON THURSDAY WILL ONLY AGAIN BE HOT WITH TEMPERATURES
ABOVE 90 ACROSS THE GREATER CAPITAL REGION SOUTHWARD. WILL LIKELY
HOIST HEAT ADVISORIES...ESPECIALLY ACROSS THE SOUTH.
THURSDAY NIGHT...ANY SHOWERS AND THUNDERSTORMS SHOULD DIMINISH WITH
THE LOSS OF HEATING. LOWS THURSDAY NIGHT WILL BE IN THE UPPER 60S
TO LOWER 70S.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ONE MORE HOT DAY...THEN THE HEAT BREAKS...
BY FRIDAY THE 500HPA RIDGE CENTER IS ALONG THE MID ATLC COAST
WITH A ZONAL W FLOW ACROSS THE N TIER OF THE USA. EMBEDDED IN THIS
FLOW IS A SHORT WV FM LK HURON TWRD CHI FRI MORNING. AT SFC A
CDFNT IS MOVING INTO UPR GRTLKS AS THE BERMUDA HIGH HAS MOVED
OFFSHORE. DURING THE DAY FRIDAY THE APPROACHING SHORT WV BUILDS
THE RIDGE SLIGHTLY INTO THE RGN AND INCR WSW FLOW. WSW FLOW WILL
RESULT IN ADDITIONAL DIABATIC WARMING EAST OF APPALACHIANS. WITH
PS TO MS SKIES...TEMPS MAY REACH MAX VALUES FOR THIS STRETCH...WITH
90S COMMON AND MID TO UPPER 90S IN VALLEYS. ONLY FACTOR THAT COULD
CUT THEM BACK IS AMOUNT OF CONVECTIVELY INDUCED CLOUD COVER. TD
WILL REMAIN IN THE 70S AND HEAT ADVISORIES OR POSSIBLE WARNINGS
MAY BE NEEDED AGAIN FOR FRI.
NAM MODEL SOUNDINGS REASSERT A CAP ACROSS RGN FRI AT 650 HPA WITH
2600 J/KG OF CAPE IS TRAPPED UNDER IT. GFS HAS SIMILAR CAP AT
740HPA...AND CAPES FM 1000-2200 J/KG. BOTH MODELS 500HPA TEMPS INCR
BACK TO -6C TO -7C FRI.
250HPA JET REMAINS WELL NORTH OF RGN MUCH OF FRI. GFS BRINGS FCA
UNDER THE INFLUENCE OF THE RIGHT ENTRANCE RGN FRI NT...WITH AREAS OF
DIVERGENCE (FORCING) MOVING INTO N TIER LATE FRI. THE NAM IS
SLOWER IN THIS TIMING. BOTH MODELS BRING 40-50KT 850HPA WSW JET INTO
THE ST LAWRENCE VLY BY FRI EVNG.
POPS IN MOST GUIDANCE SUITE ALONG LINES OF 25-35PCT FRI. WHILE CAPES
ARE LARGE...THEY WILL BE LARGELY CAPPED TILL LATE INTO THE AFTN OR
EARLY EVENING. THEN SCT TSTMS DIURNALLY AND ELEVATED TRRN DRIVEN
WILL POKE THROUGH THE CAP. TSTMS WILL BE SUSTAINED OVERNIGHT BY
BOUNDARY INTERACTIONS...INCRG DYNAMIC FORCING AND THE APPROACHING
CDFNT. SPC HAS DAY 3 SLIGHT RISK JUST TOUCHING NW PORTIONS OF
FCA...WITH THESE INCR DYNAMICS FRI NT AND WINDS THE PRIMARY CONCERN.
FRIDAY NIGHT WILL BE ANOTHER SULTRY NIGHT WITH TD AROUND 70 AND LOWS
FALLING ONLY TO THE 70S.
SATURDAY WILL BRING AN END TO THE OPPRESSIVE HEAT IN THE FCA. CDFNT
WILL MOVE INTO THE ST LAWRENCE VLY...THEN SE ACROSS THE FCA SAT. A
PREFRONTAL TROF AHEAD OF THIS CDFNT WILL INITIATE CONVECTION.
THE NAM/GEM BRINGS THESE FEATURES THROUGH DURING THE MORNING...WHILE
THE GFS DOES SO DURING PEAK HEATING OF THE DAY IN THE AFTN.
SPC HAS FCA IN DAY 4 OUTLOOK SVR...HWVR TIMING OF CDFNT WILL DICTATE
LOCATION AND MAGNITUDE OF TSTM RESPONSE. 850 JET OF 25-40 KTS AND
RIGHT ENTIRE REGION OF 250 JET LINE UP0 ACROSS RGN AS CDFNT SHIFTS
S.
ATTM THE THREAT IS GREATEST ACROSS THE S HALF FCA...AS MOST GUIDANCE
BRINGS IT THROUGH THE N AREAS BEFORE BETTER DYNAMICS ALIGN WITH THE
CDFNT AND MAX HEATING. THIS WILL BE REFINED WITH ECMWF IN GRIDS.
IN THE COLD FRONTS WAKE...MORE SEASONABLE AND COMFORTABLE AIR WILL
STREAM INTO FCA LATE SAT AND SAT NT. TD WILL FALL INTO THE 60S...AS
SKIES CLEAR.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
THE LONG TERM PERIOD WILL BE CHARACTERIZED BY A RETURN TO MORE
SEASONABLE TEMPERATURES AND INCREASING CHANCES FOR MAINLY
AFTERNOON/EARLY EVENING SHOWERS AND THUNDERSTORMS FOR NEXT WEEK.
AT THE START OF THE LONG TERM PERIOD...LONG RANGE GUIDANCE FROM THE
12Z GFS/ECMWF/GGEM ARE IN GOOD AGREEMENT WITH THE PASSAGE OF THE
COLD FRONT THROUGH THE FORECAST AREA BY SUNDAY MORNING. THIS COLD
FRONTAL PASSAGE WILL MARK AN END TO THE HEAT WAVE ACROSS THE
FORECAST AREA...WHILE ALSO USHERING IN REFRESHINGLY LOWER HUMIDITY
LEVELS AS DEWPOINTS DROP INTO THE MID TO UPPER 50S. A BROAD AREA OF
CANADIAN HIGH PRESSURE WILL GRADUALLY BUILD IN AT THE SURFACE AND
PERSIST THROUGH THE REMAINDER OF THE WEEKEND AND INTO THE BEGINNING
OF NEXT WEEK.
THE CANADIAN HIGH PRESSURE WILL SLOWLY DRIFT SOUTHWARD BY
MONDAY...ALLOWING FOR SOME WEAK SOUTHERLY/SOUTHWESTERLY RETURN FLOW
AROUND THE HIGH. THIS RETURN FLOW WILL ALLOW DEWPOINTS TO CREEP UP
SLIGHTLY TOWARDS 60 IN SOUTHERN AREAS AND GIVEN NORTHWEST FLOW
ALOFT...CANNOT RULE OUT AN ISOLATED TERRAIN-INFLUENCED
SHOWER/THUNDERSTORM OR TWO POPPING UP DURING THE AFTERNOON HOURS.
THE LONG TERM FORECAST BECOMES A LITTLE MORE UNCERTAIN BEGINNING
TUESDAY AS THE CANADIAN HIGH PRESSURE LOOSENS ITS GRIP ACROSS THE
FORECAST AREA. ALOFT...RIPPLES OF ENERGY WILL BE MOVING THROUGH THE
NORTHWEST FLOW HELPING TO TRIGGER MAINLY AFTERNOON/EARLY EVENING
SHOWERS AND THUNDERSTORMS ACROSS THE FORECAST AREA. WILL ONLY
MENTION SLIGHT CHANCE POPS AT THIS TIME AS FORCING DOES NOT APPEAR
TO BE OVERLY STRONG DURING THIS TIME PERIOD. HOWEVER...BOTH THE 12Z
ECMWF/GFS HINT AT A STRONGER SHORTWAVE MOVING THROUGH THE FLOW
THURSDAY WHICH COULD BRING AN INCREASED THREAT FOR CONVECTION BUT
THE EXACT DETAILS ARE STILL TOO EARLY TO DETERMINE AT THIS TIME.
TEMPERATURES WILL RETURN TO MORE SEASONABLE LEVELS ALONG WITH A
NOTICEABLE DECREASE IN HUMIDITY DURING THE LONG TERM PERIOD. HIGHS
WILL GENERALLY BE FROM AROUND 70 IN NORTHWEST ZONES TO THE LOWER 80S
IN SOUTHERN ZONES. LOWS WILL GENERALLY BE IN THE LOWER 50S TO LOWER
60S. TEMPERATURES AND HUMIDITY WILL SLOWLY INCREASE NEXT WEEK
WARMING INTO THE MID 80S BY THE END OF THE PERIOD WITH A RETURN TO
LOWER 60S DEWPOINTS.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
SOME CONVECTION HAS REDEVELOPED ACROSS KGFL AND KPOU WITH SEVERAL
LIGHTNING STRIKES NEAR KPOU. WE WILL HANDLE THIS WITH TEMPO GROUPS
AND/OR VICINITY AS WE MONITOR TRENDS. REMAINDER OF THE OVERNIGHT
WE WILL LIKELY SEE PATCHY FOG AND/OR HAZE FORMATION AS DEWPOINTS
REMAIN IN THE 70S FOR THE MOST PART. MAINLY SCT CIGS WITH SOME BKN
LEVELS FROM TIME TO TIMES SEEN IN THE IR SATELLITE ENHANCEMENTS.
AFTER SUNRISE...VFR CONDITIONS EXPECTED FOR THE DAY AS WE MONITOR
THE POTENTIAL FOR ADDITIONAL AFTERNOON CONVECTION. AT THIS
TIME...WE WILL PLACE A VCSH AT TAF LOCATIONS THIS AFTERNOON.
WESTERLY WINDS GENERALLY 10KTS OR LESS ARE EXPECTED.
WE ARE STARTING A NEW EXPERIMENTAL FORMAT FOR DISPLAYING THE
EXTENDED PORTION OF THE AVIATION DISCUSSION. THIS FORMAT BREAKS THE
EXTENDED PERIODS INTO 12-HOUR INCREMENTS. IT DOES NOT INCLUDE THE
POSSIBILITY OF IFR/VFR BUT THE POTENTIAL SENSIBLE WEATHER AND
"POTENTIAL" IMPACT THE WEATHER MIGHT CAUSE. WE HAVE OMITTED THE WORD
POTENTIAL TO KEEP THE VERBIAGE SHORTER.
WEDNESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIGNIFICANT WEATHER.
THURSDAY: MODERATE OPERATIONAL IMPACT. SLIGHT CHANCE OF RAIN AND
THUNDER STORMS.
THURSDAY NIGHT: MODERATE OPERATIONAL IMPACT. SLIGHT CHANCE OF
RAIN SHOWERS...THUNDER STORMS.
FRIDAY: MODERATE OPERATIONAL IMPACT. BREEZY SLIGHT CHANCE OF RAIN
SHOWERS...THUNDER STORMS.
FRIDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF RAIN
SHOWERS...THUNDER STORMS.
SATURDAY: HIGH OPERATIONAL IMPACT. LIKELY RAIN SHOWERS...THUNDER
STORMS.
SATURDAY NIGHT: NO OPERATIONAL IMPACT. NO SIGNIFICANT
WEATHER. SUNDAY: NO OPERATIONAL IMPACT. NO SIGNIFICANT WEATHER.
SUNDAY NIGHT: NO OPERATIONAL IMPACT. NO SIGNIFICANT WEATHER.
MONDAY: MODERATE OPERATIONAL IMPACT. SLIGHT CHANCE OF RAIN
SHOWERS...THUNDER STORMS.
&&
.FIRE WEATHER...
HIGH PRESSURE AT ALL LEVELS OF THE ATMOSPHERE...WILL RECEDE FROM
THE MIDWEST TO THE ATLANTIC SEABOARD BY FRIDAY. A WEAK BOUNDARY WILL
DRIFT INTO AND OUT THE SAINT LAWRENCE TONIGHT AND
THURSDAY...TRIGGERING SCATTERED THUNDERSTORMS. OTHERWISE THE HEAT
AND HUMIDITY WILL PERSIST INTO UGH SATURDAY. A STRONG COLD FRONT
WILL PUSH THROUGH THE REGION SATURDAY...TRIGGERING THUNDERSTORMS AND
USHERING IN MORE A MORE SEASONABLE AIR MASS INTO OUR REGION TO START
THE NEW WEEK.
RH VALUES WILL REMAIN ELEVATED FOR THE NEXT SEVERAL DAYS. LOOK FOR
FULL RECOVERIES AT NIGHT AND RH VALUES ONLY DROPPING TO 40 TO 60
PERCENT EACH AFTERNOON (HIGHEST ACROSS THE MOUNTAINS).
SCATTERED MAINLY AFTERNOON AND EVENING THUNDERSTORMS ARE POSSIBLE
INTO FRIDAY NIGHT. MORE NUMEROUS SHOWERS AND THUNDERSTORMS ARE
POSSIBLE SATURDAY. HEAVY RAINFALL WILL BE POSSIBLE WITH ANY
THUNDERSTORMS...ESPECIALLY SATURDAY.
&&
.HYDROLOGY...
SCATTERED MAINLY AFTERNOON AND EVENING THUNDERSTORMS ARE POSSIBLE
INTO FRIDAY NIGHT. MORE NUMEROUS SHOWERS AND THUNDERSTORMS ARE
POSSIBLE SATURDAY. HEAVY RAINFALL WILL BE POSSIBLE WITH ANY
THUNDERSTORMS...ESPECIALLY SATURDAY.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.CLIMATE...
TO ACCESS HEAT RELATED CLIMATE DATA INCLUDING HEAT WAVES...NUMBER
90+ DEGREES DAYS AND 100+ DEGREES DAYS...PLEASE VISIT
WWW.WEATHER.GOV/ALY/CLIMATE (ALL LOWER CASE) AND GO TO THE
RECORDS... EXTREMES... PAGE FOR ALBANY.
NUMBER OF 90+ DEGREE DAYS AND RECORD HIGHS...
ALBANY NY...
2013 MAY: 1 DAY
2013 JUNE: 4 DAYS
2013 JULY: 6 DAYS
2012: 13 DAYS
2011: 8 DAYS
2010: 14 DAYS
NORMAL: 10 DAYS
RECORD HIGHS: (DATE BACK TO 1874)
JULY 17: 99 DEGREES 1900
JULY 18: 100 DEGREES 1953
JULY 19: 97 DEGREES 1904
GLENS FALLS NY...
2013 MAY: 1 DAY
2013 JUNE: 2 DAYS
2013 JULY: 3 DAYS
2012: 8 DAYS
RECORD HIGHS: (DATE BACK TO 1949)
JULY 17: 99 DEGREES 1953
JULY 18: 97 DEGREES 1953
JULY 19: 95 DEGREES 1977
POUGHKEEPSIE NY...
2013 MAY: 3 DAY
2013 JUNE: 4 DAYS
2013 JULY: 7 DAYS
2012: 22 DAYS
RECORD HIGHS: (DATE BACK TO 1949)
JULY 17: 98 DEGREES 2006
JULY 18: 100 DEGREES 1991
JULY 19: 102 DEGREES 1991
BENNINGTON VT...
2013 MAY: NONE
2013 JUNE: NONE
2013 JULY: 1 DAY
2012: 7 DAYS
PITTSFIELD MA...
2013 MAY: NONE
2013 JUNE: NONE
2013 JULY: NONE
2012: 3 DAYS
&&
.EQUIPMENT...
KENX NATIONAL WEATHER SERVICE DOPPLER RADAR WILL BE UNAVAILABLE
THROUGH EARLY AUGUST. A MAJOR HARDWARE FAILURE WITH THE RADAR HAS
BEEN IDENTIFIED. FIXING THIS WILL REQUIRE HEAVY DUTY EQUIPMENT AND
A TEAM OF EMPLOYEES FROM THE RADAR OPERATIONS CENTER. WE APOLOGIZE
FOR THE INCONVENIENCE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM EDT THIS
EVENING FOR NYZ064>066.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...NAS
NEAR TERM...NAS
SHORT TERM...SNYDER
LONG TERM...IRL
AVIATION...BGM
FIRE WEATHER...SNYDER
HYDROLOGY...SNYDER
CLIMATE...WFOALY
EQUIPMENT...WFOALY
AREA FORECAST DISCUSSION
NWS ALBANY NY
1240 AM EDT THU JUL 18 2013
.SYNOPSIS...
HIGH PRESSURE AT ALL LEVELS OF THE ATMOSPHERE...WILL RECEDE FROM
THE MIDWEST TO THE ATLANTIC SEABOARD BY FRIDAY. A WEAK BOUNDARY WILL
DRIFT INTO AND OUT THE SAINT LAWRENCE TONIGHT AND
THURSDAY...TRIGGERING SCATTERED THUNDERSTORMS. OTHERWISE THE HEAT
AND HUMIDITY WILL PERSIST INTO UGH SATURDAY. A STRONG COLD FRONT
WILL PUSH THROUGH THE REGION SATURDAY...TRIGGERING THUNDERSTORMS AND
USHERING IN MORE A MORE SEASONABLE AIR MASS INTO OUR REGION TO START
THE NEW WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 1230 AM EDT...RADARS STILL INDICATING WIDELY SCATTERED SHOWER
ACTIVITY ACROSS THE ADIRONDACKS...EASTWARD INTO SOUTHERN VERMONT.
THESE APPEARED TO BE TIED INTO A WEAK BOUNDARY JUST TO NORTH OF THIS
REGION. INTERESTING THE EXPERIMENTAL HRRR HAS INDICATED A BROKEN
LINE OF SHOWERS AND POSSIBLY THUNDERSTORMS WORKING SOUTH THROUGH THE
CAPITAL REGION AND EVEN POINTS SOUTH OVERNIGHT.
WHILE THIS SCENARIO CANNOT BE RULED OUT...WE LEAN AGAINST IT SINCE
OUR RAOB INDICATED OUR MID LEVELS REMAINED CAPPED (VERY WARM
TEMPERATURES AROUND +10C AROUND 10,000 FEET) WHICH HAS BEEN ABLE TO
SUPPRESS CONVECTION THUS FAR. ALSO...WE HAVE LOST THE HEATING OF THE
DAY AND THE FRONT SHOULD STAY NORTH. THERE WAS ONE INTERESTING
FEATURE ON THE H20 VAPOR LOOP...A DISTINCT DRY PUNCH WELL TO OUR
NORTH WHICH COULD ALSO BE CONTRIBUTING TO THE SHOWER ACTIVITY. THIS
FEATURE SHOULD ALSO STAY TO THE NORTH.
WE DID EXTENT ISOLATED COVERAGE OF SHOWERS (AND SLIGHT CHANCE OF
THUNDERSTORMS) SOUTH TO ABOUT SARATOGA SPRINGS FOR A COUPLE OF
HOURS...WHILE KEEPING AREAS FROM THE CAPITAL DISTRICT SOUTHWARD DRY
(POPS LESS THAN 15 PERCENT).
THIS LEAVES US WITH AN OPPRESSIVE NIGHT. TEMPERATURES WERE STILL
OVER 80S IN THE CAPITAL DISTRICT...AND CLOSE TO 80 ACROSS MOST OTHER
AREAS. DEWPOINTS WERE AROUND 70. AND NOW WE ALSO HAVE SOME HAZE TON
CONTEND WITH.
THERE WAS STILL A LITTLE BREEZE OUT OF THE WEST WHICH COULD KEEP UP
IN SOME AREAS ALL NIGHT LONG.
FOR ALL THE ABOVE REASONS...RAISED TEMPERATURES A COUPLE DEGREES
ACROSS MANY AREAS. THIS WOULD MEAN OVERNIGHT LOWS WOULD ONLY FALL
TO ABOUT THE MID 70S FROM ALBANY SOUTHWARD...CLOSER TO 70 IN
OUTLYING AREAS. THESE VALUES WILL AVERAGE MORE THAN 10 DEGREES ABOVE
NORMAL FOR THE TIME OF YEAR.
THURSDAY...THE CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE ON THE
INCREASE DURING THE AFTERNOON. THE UPPER LEVEL HIGH PRESSURE WILL BE
SUPPRESSED TO THE SOUTH. THIS WILL CHANGE OUR FLOW TO ZONAL FLOW.
THIS COULD ALLOW FOR A DISTURBANCE OR TWO EMBEDDED IN THE INCREASING
FLOW TO MOVE THROUGH AND PRODUCE SCATTERED CONVECTION MAINLY DURING
THE AFTERNOON AND EVENING. MODELS ARE SHOWING DECENT CAPE ACROSS THE
REGION FROM 1000 J/KG TO 2500 J/KG.
TEMPERATURES ON THURSDAY WILL ONLY AGAIN BE HOT WITH TEMPERATURES
ABOVE 90 ACROSS THE GREATER CAPITAL REGION SOUTHWARD. WILL LIKELY
HOIST HEAT ADVISORIES...ESPECIALLY ACROSS THE SOUTH.
THURSDAY NIGHT...ANY SHOWERS AND THUNDERSTORMS SHOULD DIMINISH WITH
THE LOSS OF HEATING. LOWS THURSDAY NIGHT WILL BE IN THE UPPER 60S
TO LOWER 70S.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ONE MORE HOT DAY...THEN THE HEAT BREAKS...
BY FRIDAY THE 500HPA RIDGE CENTER IS ALONG THE MID ATLC COAST
WITH A ZONAL W FLOW ACROSS THE N TIER OF THE USA. EMBEDDED IN THIS
FLOW IS A SHORT WV FM LK HURON TWRD CHI FRI MORNING. AT SFC A
CDFNT IS MOVING INTO UPR GRTLKS AS THE BERMUDA HIGH HAS MOVED
OFFSHORE. DURING THE DAY FRIDAY THE APPROACHING SHORT WV BUILDS
THE RIDGE SLIGHTLY INTO THE RGN AND INCR WSW FLOW. WSW FLOW WILL
RESULT IN ADDITIONAL DIABATIC WARMING EAST OF APPALACHIANS. WITH
PS TO MS SKIES...TEMPS MAY REACH MAX VALUES FOR THIS STRETCH...WITH
90S COMMON AND MID TO UPPER 90S IN VALLEYS. ONLY FACTOR THAT COULD
CUT THEM BACK IS AMOUNT OF CONVECTIVELY INDUCED CLOUD COVER. TD
WILL REMAIN IN THE 70S AND HEAT ADVISORIES OR POSSIBLE WARNINGS
MAY BE NEEDED AGAIN FOR FRI.
NAM MODEL SOUNDINGS REASSERT A CAP ACROSS RGN FRI AT 650 HPA WITH
2600 J/KG OF CAPE IS TRAPPED UNDER IT. GFS HAS SIMILAR CAP AT
740HPA...AND CAPES FM 1000-2200 J/KG. BOTH MODELS 500HPA TEMPS INCR
BACK TO -6C TO -7C FRI.
250HPA JET REMAINS WELL NORTH OF RGN MUCH OF FRI. GFS BRINGS FCA
UNDER THE INFLUENCE OF THE RIGHT ENTRANCE RGN FRI NT...WITH AREAS OF
DIVERGENCE (FORCING) MOVING INTO N TIER LATE FRI. THE NAM IS
SLOWER IN THIS TIMING. BOTH MODELS BRING 40-50KT 850HPA WSW JET INTO
THE ST LAWRENCE VLY BY FRI EVNG.
POPS IN MOST GUIDANCE SUITE ALONG LINES OF 25-35PCT FRI. WHILE CAPES
ARE LARGE...THEY WILL BE LARGELY CAPPED TILL LATE INTO THE AFTN OR
EARLY EVENING. THEN SCT TSTMS DIURNALLY AND ELEVATED TRRN DRIVEN
WILL POKE THROUGH THE CAP. TSTMS WILL BE SUSTAINED OVERNIGHT BY
BOUNDARY INTERACTIONS...INCRG DYNAMIC FORCING AND THE APPROACHING
CDFNT. SPC HAS DAY 3 SLIGHT RISK JUST TOUCHING NW PORTIONS OF
FCA...WITH THESE INCR DYNAMICS FRI NT AND WINDS THE PRIMARY CONCERN.
FRIDAY NIGHT WILL BE ANOTHER SULTRY NIGHT WITH TD AROUND 70 AND LOWS
FALLING ONLY TO THE 70S.
SATURDAY WILL BRING AN END TO THE OPPRESSIVE HEAT IN THE FCA. CDFNT
WILL MOVE INTO THE ST LAWRENCE VLY...THEN SE ACROSS THE FCA SAT. A
PREFRONTAL TROF AHEAD OF THIS CDFNT WILL INITIATE CONVECTION.
THE NAM/GEM BRINGS THESE FEATURES THROUGH DURING THE MORNING...WHILE
THE GFS DOES SO DURING PEAK HEATING OF THE DAY IN THE AFTN.
SPC HAS FCA IN DAY 4 OUTLOOK SVR...HWVR TIMING OF CDFNT WILL DICTATE
LOCATION AND MAGNITUDE OF TSTM RESPONSE. 850 JET OF 25-40 KTS AND
RIGHT ENTIRE REGION OF 250 JET LINE UP0 ACROSS RGN AS CDFNT SHIFTS
S.
ATTM THE THREAT IS GREATEST ACROSS THE S HALF FCA...AS MOST GUIDANCE
BRINGS IT THROUGH THE N AREAS BEFORE BETTER DYNAMICS ALIGN WITH THE
CDFNT AND MAX HEATING. THIS WILL BE REFINED WITH ECMWF IN GRIDS.
IN THE COLD FRONTS WAKE...MORE SEASONABLE AND COMFORTABLE AIR WILL
STREAM INTO FCA LATE SAT AND SAT NT. TD WILL FALL INTO THE 60S...AS
SKIES CLEAR.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
THE LONG TERM PERIOD WILL BE CHARACTERIZED BY A RETURN TO MORE
SEASONABLE TEMPERATURES AND INCREASING CHANCES FOR MAINLY
AFTERNOON/EARLY EVENING SHOWERS AND THUNDERSTORMS FOR NEXT WEEK.
AT THE START OF THE LONG TERM PERIOD...LONG RANGE GUIDANCE FROM THE
12Z GFS/ECMWF/GGEM ARE IN GOOD AGREEMENT WITH THE PASSAGE OF THE
COLD FRONT THROUGH THE FORECAST AREA BY SUNDAY MORNING. THIS COLD
FRONTAL PASSAGE WILL MARK AN END TO THE HEAT WAVE ACROSS THE
FORECAST AREA...WHILE ALSO USHERING IN REFRESHINGLY LOWER HUMIDITY
LEVELS AS DEWPOINTS DROP INTO THE MID TO UPPER 50S. A BROAD AREA OF
CANADIAN HIGH PRESSURE WILL GRADUALLY BUILD IN AT THE SURFACE AND
PERSIST THROUGH THE REMAINDER OF THE WEEKEND AND INTO THE BEGINNING
OF NEXT WEEK.
THE CANADIAN HIGH PRESSURE WILL SLOWLY DRIFT SOUTHWARD BY
MONDAY...ALLOWING FOR SOME WEAK SOUTHERLY/SOUTHWESTERLY RETURN FLOW
AROUND THE HIGH. THIS RETURN FLOW WILL ALLOW DEWPOINTS TO CREEP UP
SLIGHTLY TOWARDS 60 IN SOUTHERN AREAS AND GIVEN NORTHWEST FLOW
ALOFT...CANNOT RULE OUT AN ISOLATED TERRAIN-INFLUENCED
SHOWER/THUNDERSTORM OR TWO POPPING UP DURING THE AFTERNOON HOURS.
THE LONG TERM FORECAST BECOMES A LITTLE MORE UNCERTAIN BEGINNING
TUESDAY AS THE CANADIAN HIGH PRESSURE LOOSENS ITS GRIP ACROSS THE
FORECAST AREA. ALOFT...RIPPLES OF ENERGY WILL BE MOVING THROUGH THE
NORTHWEST FLOW HELPING TO TRIGGER MAINLY AFTERNOON/EARLY EVENING
SHOWERS AND THUNDERSTORMS ACROSS THE FORECAST AREA. WILL ONLY
MENTION SLIGHT CHANCE POPS AT THIS TIME AS FORCING DOES NOT APPEAR
TO BE OVERLY STRONG DURING THIS TIME PERIOD. HOWEVER...BOTH THE 12Z
ECMWF/GFS HINT AT A STRONGER SHORTWAVE MOVING THROUGH THE FLOW
THURSDAY WHICH COULD BRING AN INCREASED THREAT FOR CONVECTION BUT
THE EXACT DETAILS ARE STILL TOO EARLY TO DETERMINE AT THIS TIME.
TEMPERATURES WILL RETURN TO MORE SEASONABLE LEVELS ALONG WITH A
NOTICEABLE DECREASE IN HUMIDITY DURING THE LONG TERM PERIOD. HIGHS
WILL GENERALLY BE FROM AROUND 70 IN NORTHWEST ZONES TO THE LOWER 80S
IN SOUTHERN ZONES. LOWS WILL GENERALLY BE IN THE LOWER 50S TO LOWER
60S. TEMPERATURES AND HUMIDITY WILL SLOWLY INCREASE NEXT WEEK
WARMING INTO THE MID 80S BY THE END OF THE PERIOD WITH A RETURN TO
LOWER 60S DEWPOINTS.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
VFR CONDITIONS AT TAF LOCATIONS THROUGH THIS EVENING...WITH A
POSSIBLE LIGHT SHOWER AROUND KGFL FOR PART OF THIS EVENING. OTHER
ISOLATED CONVECTION UPSTREAM SHOULD NOT REACH THE TAF SITES THIS
EVENING...AND WILL WATCH CONVECTION IN CANADA TO SEE IF IT FLIRTS
WITH KGFL OR KALB BETWEEN 06Z-12Z BUT THAT IS DOUBTFUL AT THIS
TIME. WINDS TONIGHT SHOULD BE NEAR CALM AND SOME FOG IS POSSIBLE
AT ALL SITES AFTER 04Z-06Z THROUGH ABOUT 12Z-13Z. VFR CONDITIONS
SHOULD PREVAIL TOMORROW WITH SOME ISOLATED TO SCATTERED
THUNDERSTORM ACTIVITY POSSIBLE AFTER 20Z-22Z. WINDS TOMORROW
SHOULD BE WEST TO SOUTHWEST AT LESS THAN 10Z
WE ARE STARTING A NEW EXPERIMENTAL FORMAT FOR DISPLAYING THE
EXTENDED PORTION OF THE AVIATION DISCUSSION. THIS FORMAT BREAKS THE
EXTENDED PERIODS INTO 12-HOUR INCREMENTS. IT DOES NOT INCLUDE THE
POSSIBILITY OF IFR/VFR BUT THE POTENTIAL SENSIBLE WEATHER AND
"POTENTIAL" IMPACT THE WEATHER MIGHT CAUSE. WE HAVE OMITTED THE WORD
POTENTIAL TO KEEP THE VERBIAGE SHORTER.
WEDNESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIGNIFICANT WEATHER.
THURSDAY: MODERATE OPERATIONAL IMPACT. SLIGHT CHANCE OF RAIN AND
THUNDER STORMS.
THURSDAY NIGHT: MODERATE OPERATIONAL IMPACT. SLIGHT CHANCE OF
RAIN SHOWERS...THUNDER STORMS.
FRIDAY: MODERATE OPERATIONAL IMPACT. BREEZY SLIGHT CHANCE OF RAIN
SHOWERS...THUNDER STORMS.
FRIDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF RAIN
SHOWERS...THUNDER STORMS.
SATURDAY: HIGH OPERATIONAL IMPACT. LIKELY RAIN SHOWERS...THUNDER
STORMS.
SATURDAY NIGHT: NO OPERATIONAL IMPACT. NO SIGNIFICANT
WEATHER. SUNDAY: NO OPERATIONAL IMPACT. NO SIGNIFICANT WEATHER.
SUNDAY NIGHT: NO OPERATIONAL IMPACT. NO SIGNIFICANT WEATHER.
MONDAY: MODERATE OPERATIONAL IMPACT. SLIGHT CHANCE OF RAIN
SHOWERS...THUNDER STORMS.
&&
.FIRE WEATHER...
HIGH PRESSURE AT ALL LEVELS OF THE ATMOSPHERE...WILL RECEDE FROM
THE MIDWEST TO THE ATLANTIC SEABOARD BY FRIDAY. A WEAK BOUNDARY WILL
DRIFT INTO AND OUT THE SAINT LAWRENCE TONIGHT AND
THURSDAY...TRIGGERING SCATTERED THUNDERSTORMS. OTHERWISE THE HEAT
AND HUMIDITY WILL PERSIST INTO UGH SATURDAY. A STRONG COLD FRONT
WILL PUSH THROUGH THE REGION SATURDAY...TRIGGERING THUNDERSTORMS AND
USHERING IN MORE A MORE SEASONABLE AIR MASS INTO OUR REGION TO START
THE NEW WEEK.
RH VALUES WILL REMAIN ELEVATED FOR THE NEXT SEVERAL DAYS. LOOK FOR
FULL RECOVERIES AT NIGHT AND RH VALUES ONLY DROPPING TO 40 TO 60
PERCENT EACH AFTERNOON (HIGHEST ACROSS THE MOUNTAINS).
SCATTERED MAINLY AFTERNOON AND EVENING THUNDERSTORMS ARE POSSIBLE
INTO FRIDAY NIGHT. MORE NUMEROUS SHOWERS AND THUNDERSTORMS ARE
POSSIBLE SATURDAY. HEAVY RAINFALL WILL BE POSSIBLE WITH ANY
THUNDERSTORMS...ESPECIALLY SATURDAY.
&&
.HYDROLOGY...
SCATTERED MAINLY AFTERNOON AND EVENING THUNDERSTORMS ARE POSSIBLE
INTO FRIDAY NIGHT. MORE NUMEROUS SHOWERS AND THUNDERSTORMS ARE
POSSIBLE SATURDAY. HEAVY RAINFALL WILL BE POSSIBLE WITH ANY
THUNDERSTORMS...ESPECIALLY SATURDAY.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.CLIMATE...
TO ACCESS HEAT RELATED CLIMATE DATA INCLUDING HEAT WAVES...NUMBER
90+ DEGREES DAYS AND 100+ DEGREES DAYS...PLEASE VISIT
WWW.WEATHER.GOV/ALY/CLIMATE (ALL LOWER CASE) AND GO TO THE
RECORDS... EXTREMES... PAGE FOR ALBANY.
NUMBER OF 90+ DEGREE DAYS AND RECORD HIGHS...
ALBANY NY...
2013 MAY: 1 DAY
2013 JUNE: 4 DAYS
2013 JULY: 6 DAYS
2012: 13 DAYS
2011: 8 DAYS
2010: 14 DAYS
NORMAL: 10 DAYS
RECORD HIGHS: (DATE BACK TO 1874)
JULY 17: 99 DEGREES 1900
JULY 18: 100 DEGREES 1953
JULY 19: 97 DEGREES 1904
GLENS FALLS NY...
2013 MAY: 1 DAY
2013 JUNE: 2 DAYS
2013 JULY: 3 DAYS
2012: 8 DAYS
RECORD HIGHS: (DATE BACK TO 1949)
JULY 17: 99 DEGREES 1953
JULY 18: 97 DEGREES 1953
JULY 19: 95 DEGREES 1977
POUGHKEEPSIE NY...
2013 MAY: 3 DAY
2013 JUNE: 4 DAYS
2013 JULY: 7 DAYS
2012: 22 DAYS
RECORD HIGHS: (DATE BACK TO 1949)
JULY 17: 98 DEGREES 2006
JULY 18: 100 DEGREES 1991
JULY 19: 102 DEGREES 1991
BENNINGTON VT...
2013 MAY: NONE
2013 JUNE: NONE
2013 JULY: 1 DAY
2012: 7 DAYS
PITTSFIELD MA...
2013 MAY: NONE
2013 JUNE: NONE
2013 JULY: NONE
2012: 3 DAYS
&&
.EQUIPMENT...
KENX NATIONAL WEATHER SERVICE DOPPLER RADAR WILL BE UNAVAILABLE
THROUGH EARLY AUGUST. A MAJOR HARDWARE FAILURE WITH THE RADAR HAS
BEEN IDENTIFIED. FIXING THIS WILL REQUIRE HEAVY DUTY EQUIPMENT AND
A TEAM OF EMPLOYEES FROM THE RADAR OPERATIONS CENTER. WE APOLOGIZE
FOR THE INCONVENIENCE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM EDT THIS
EVENING FOR NYZ064>066.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...NAS
NEAR TERM...NAS
SHORT TERM...SNYDER
LONG TERM...IRL
AVIATION...NAS
FIRE WEATHER...SNYDER
HYDROLOGY...SNYDER
CLIMATE...WFOALY
EQUIPMENT...WFOALY
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
128 AM EDT THU JUL 18 2013
.SHORT TERM /REMAINDER OF TONIGHT/...
/ISSUED AT 1105 PM EDT WED JUL 17 2013/
EASTERLY FLOW CONTINUES OVER THE AREA. ENOUGH INSTABILITY REMAIN FOR
CONVECTION TO CONTINUE FIRING OVER THE AREA. THOUGH MUCH OF THE
THUNDERSTORM ACTIVITY OVER NORTH GEORGIA HAS DIMINISHED TO
SHOWERS...A FEW EMBEDDED THUNDERSTORMS CONTINUE TO DEVELOP. THE
SOUTHERN PORTION OF THE FORECAST AREA HAS BECOME MORE ACTIVE WITH
THUNDERSTORM DEVELOPMENT...MAINLY ALONG SOME OF THE BOUNDARIES FROM
PREVIOUS STORMS TO THE NORTH. THE ANTICIPATION IS FOR THESE STORMS
TO ALL WEAKEN AND DIMINISH OVER THE NEXT FEW HOURS...AND MOSTLY
CLOUDY CLOUDY SKIES TO CONTINUE INTO MORNING.
&&
.PREVIOUS DISCUSSION...ISSUED AT 330 PM...
SHORT TERM/TONIGHT THROUGH THURSDAY NIGHT/...
CURRENT SATELLITE LOOP SHOWS MAIN EASTERN WAVE MOVING INTO NE GA AT
THE MOMENT. THE CURRENT RADAR LOP SHOWS SHOWERS AND ISOLATED
THUNDERSTORMS POPPING UP ACROSS NE GA WHICH IS DEFINITELY BEING
GENERATED BY THIS WAVE. THE MAIN ENERGY FROM THIS WAVE IS EXPECTED
TO STAY ACROSS NORTH GA BUT BOTH OUR LOCAL WRF AND THE HRRR SHOW A
BIT MORE DIURNALLY DRIVEN POP UP SHRA/TSRA ACROSS THE STATE THROUGH
02-04Z TONIGHT. THE SURFACE TO UPPER LEVEL RIDGE KEEPS OUR AREA IN
MOIST EASTERLY FLOW THROUGH THE SHORT TERM. THE MODELS ARE SHOWING
ANOTHER WEAKER WAVE MOVING ACROSS THE AREA THU IN THIS EASTERLY
FLOW. WITH THIS IN MIND SHOULD SEE ANOTHER DIURNALLY DRIVEN
CONVECTIVE DAY THU. THERE IS VERY LITTLE SHEAR IN THIS ATMOSPHERE
BUT THE CAPES AND LIS BOTH PEAK BETWEEN 18Z AND 00Z THIS AFTERNOON
AND THURSDAY. TODAY SHOULD BE THE WARMEST DAY THIS WEEK WITH RISING
THICKNESSES TODAY HOWEVER PRECIP/CLOUDS MAY OFFSET THE WARMING A
LITTLE. H5 HEIGHTS WILL BE DROPPING THURSDAY YIELDING A SLIGHTLY
COOLER TEMPS. STAYING CLOSE TO CURRENT FORECAST TEMPS AS THEY STILL
LOOKS GOOD.
01
LONG TERM /FRIDAY THROUGH WEDNESDAY/...
NO SIG CHANGES TO THE EXTENDED. ONLY CHANGE WERE TO THE POPS ON
SUNDAY WHERE OUR NEIGHBORS AND GUIDANCE SUGGESTS A LIKELY CHANCE
OF POPS. DECIDED TO GO WITH THAT FOR SUNDAY AFTERNOON. OTHERWISE
UPDATED THE DEWPOINTS...WINDS AND TEMPERATURES WITH NEW GUIDANCE.
HAVE ATTACHED PREVIOUS DISCUSSION FOR BREVITY.
ARG
LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
/ISSUED AT 355 AM EDT WED JUL 17 2013/
A TRANSITION TAKES PLACE THIS PERIOD FROM EAST FLOW ALOFT TO
WESTERLY FLOW WITH A UPPER TROUGH DEVELOPING OVER THE EASTERN
STATES. GFS AND EUROPEAN ARE SIMILAR WITH THIS CHANGE UNTIL THE
MONDAY TO WEDNESDAY TIME FRAME WHEN THE EUROPEAN MOVES THE TROUGH
TO THE WESTERN ATLANTIC AND THE GFS KEEPS THE UPPER TROUGH OVER THE
OH/TN VALLEYS AS A STRONGER UPPER SHORT WAVE MOVES OVER THE MID U.S.
PLENTY OF MOISTURE AND INSTABILITY THIS PERIOD FOR AT LEAST
SCATTERED SHOWERS AND THUNDERSTORMS FOR MOST AREAS...TENDING TO
MAXIMIZE IN THE AFTERNOON AND EVENING HOURS. DEEPER MOISTURE MOVES
ACROSS THE AREA WITH THE INITIAL ONSET OF THE UPPER TROUGH
SUNDAY/MONDAY AS A FRONT BECOMES STATIONARY JUST N OF GA AND A
SURFACE TROUGH SETS UP FROM THE CAROLINAS INTO GA. TEMPERATURES
GENERALLY CLOSE TO NORMAL EXCEPT HIGH TEMPERATURES WILL RUN
SLIGHTLY BELOW NORMAL FROM SATURDAY ON.
BDL
&&
.AVIATION...
06Z UPDATE...
RAINFALL SLOWLY ENDING WITH MOST SITES PRECIP FREE. SKIES ARE
CLEARING AND EXPECT SOME MVFR CLOUDS...MOSTLY FEW TO SCT ALONG WITH
AREAS OF FOG. EXPECT ISOLATED TO SCATTERED CONVECTION TO DEVELOP
AFTER 18Z BUT DO NOT EXPECT IT TO BE AS EXTENSIVE AS WEDNESDAY AND
WILL MAINTAIN A PROB30 TSRA THIS AFTERNOON. WINDS WILL REMAIN A
LIGHT SOUTHEAST TODAY WITH CALM OR NEAR CALM EARLY THIS MORNING AND
AGAIN TONIGHT.
//ATL CONFIDENCE...06Z UPDATE...
MODERATE ON CIG AND VSBY EARLY THIS MORNING.
HIGH ON ALL REMAINING ELEMENTS.
17
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 71 92 71 90 / 40 30 30 40
ATLANTA 74 91 73 88 / 40 30 30 50
BLAIRSVILLE 69 88 68 84 / 40 50 30 50
CARTERSVILLE 70 91 71 89 / 40 40 30 50
COLUMBUS 73 94 73 90 / 20 30 30 50
GAINESVILLE 73 90 73 88 / 40 40 30 50
MACON 71 92 71 90 / 30 30 20 40
ROME 71 92 71 90 / 40 40 30 50
PEACHTREE CITY 71 91 70 89 / 40 30 30 50
VIDALIA 72 93 72 89 / 20 30 20 40
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...01
LONG TERM....ARG
AVIATION...37
AREA FORECAST DISCUSSION
NWS LINCOLN IL
334 AM CDT THU JUL 18 2013
.DISCUSSION...
ISSUED 330 AM CDT THU JUL 18 2013
SHORT TERM...TODAY THROUGH SUNDAY
STRONG 598 DM 500 MB HIGH PRESSURE RIDGE FROM MO AND CENTRAL IL
INTO THE OHIO VALLEY WILL CONTINUE THE HEAT WAVE ACROSS IL
THROUGH FRIDAY WITH HOT AND HUMID CONDITIONS. HEAT INDICES GRADUALLY
GETTING HIGHER EACH DAY DURING THIS WORK WEEK. HEAT INDICES THAT
REACHED 97-102F YESTERDAY AFTERNOON WILL REACH 99-104F THIS
AFTERNOON AND 101-106F FRIDAY AFTERNOON. WILL ISSUE SPECIAL
WEATHER STATEMENT TO ADDRESS THIS HEAT WAVE AND A HEAT ADIVSORY
MAY EVENTUALLY BE NEEDED FRIDAY AFTERNOON WHICH APPEARS TO BE THE
HOTTEST DAY OVER CENTRAL IL WITH HIGHS IN THE 90S. 850 MB TEMPS
ELEVATE TO 19-20C THIS AFTERNOON AND NW AREAS PEAK FROM 20-22C FRI
AFTERNOON AND SUPPORTS EVENT HOTTER CONDITIONS FRIDAY.
SOME SHORT WAVE ENERGY OVER THE TN VALLEY WILL DRIFT WESTWARD
DURING TODAY AND COULD BRING ISOLATED CONVECTION TO FAR SE IL LATE
THIS AFTERNOON/EARLY EVENING AND ADDED 20% POPS FROM ROBINSON TO
LOUSIVILLE SOUTH. LESS THAN 10% CHANCE OF A SHOWER OR THUNDERSTORM
IN TROPICAL AIR MASS FROM 3-7 PM OVER CENTRAL IL SIMILAR TO
YESTERDAY WHEN BLOOMINGTON AIRPORT PICKED UP 1 INCH OF RAIN IN A
HALF HOUR FROM 415-445 PM. SCATTERED CUMULUS CLOUDS DEVELOP LATE
MORNING AND AFTERNOON WITH PARTLY TO MOSTLY SUNNY SKIES. THESE
CUMULUS CLOUDS DISSIPATE AT SUNDOWN LEAVING FAIR SKIES AGAIN
TONIGHT. HIGHS THIS AFTERNOON 90-95F WITH LOWS TONIGHT IN LOW TO
MID 70S. HIGHS FRIDAY AFTERNOON GENERALLY IN THE MID 90S WITH A
FEW UPPER 90S POSSIBLE NW OF THE IL RIVER WHERE 925-850 MB TEMPS
HIGHEST WITH COMPRESSIONAL HEATING AHEAD OF COLD FRONT SINKING
SOUTHWARD TOWARD NORTHERN IL FROM WI.
MODELS HAVE TRENDED SLOWER WITH COLD FRONT MOVING SOUTHWARD
THROUGH CENTRAL IL FRIDAY NIGHT/SAT AND HAVE TRENDED WX/POPS IN
THAT DIRECTION. JUST SLIGHT CHANCE OF CONVECTION FRI AFTERNOON
MAINLY LATE FROM PEORIA NORTH AND NEAR THE WABASH RIVER VALLEY.
BRING BETTER CHANCES OF CONVECTION INTO CENTRAL IL FRI NIGHT AND
BEST CHANCES SHIFT INTO SE IL DURING SAT. SPC HAS SLIGHT RISK OF
SEVERE STORMS NE OF A PEORIA TO DANVILLE LINE FRI NIGHT AND ACROSS
EASTERN IL SAT. LINGERED A 20-30% CHANCE OF CONVECTION SE OF I-70
SAT EVENING THEN DRY CONDITIONS EXPECTED REST OF SAT NIGHT INTO
SUNDAY. HIGHS IN THE MID TO UPPER 80S SAT WITH SE IL AROUND 90F
COOL INTO THE LOW TO MID 80S FOR HIGHS SUNDAY AS DEWPOINTS LOWER.
LONG TERM...SUNDAY NIGHT THROUGH WEDNESDAY
IL ENTRENCHED IN A WNW UPPER LEVEL FLOW DURING FIRST HALF OF NEXT
WEEK WITH A COUPLE DISTURBANCES AND POSSIBLE MCS TO TRACK ESE
THROUGH THE MIDWEST DURING THIS TIME. ONE APPEARS TO MOVE THROUGH
SUNDAY NIGHT/MONDAY AND ANOTHER ONE TUE NIGHT/WED. INCREASING
HUMIDITY DURING THIS TIME AS WELL WITH DEWPOINTS RISING BACK INTO
THE LOW TO MID 70S. ANY OUTFLOW BOUNDARY FROM THESE MCS COULD
DEVELOP ISOLATED/SCATTERED CONVECTION EACH AFTERNOON/EVENING.
HIGHS IN THE LOW TO MID 80S MONDAY AND MID TO UPPER 80S TUE/WED.
LOWS IN THE UPPER 60S AND LOWER 70S EXPECTED DURING THIS TIME FRAME.
07
&&
.AVIATION...
ISSUED 1135 PM CDT WED JUL 17 2013
MAIN CONCERN REMAINS WITH MVFR CONDITIONS WITH LIGHT FOG
OVERNIGHT. HAVE BEEN SEEING VISIBILITIES LOWERING TO AROUND 7SM
ALREADY NEAR THE INDIANA BORDER AND CREEPING NORTHWEST...AND WINDS
ARE BASICALLY CALM. KBMI IS THE ONLY ONE THAT HAS SEEN DECENT
RAINFALL OVER THE LAST COUPLE DAYS WHICH WILL ADD MOISTURE TO THE
AIR...AND STILL THINK THEY WILL BE THE MOST LIKELY TO SEE MVFR
CONDITIONS. LATEST RAP MODEL FOCUSES THE THICKEST FOG JUST SOUTH
OF KCMI/KDEC...AND WILL MAINTAIN THE TEMPO PERIODS OF LIGHT FOG.
DAYTIME HOURS ON THURSDAY WILL BE SIMILAR TO WEDNESDAY...I.E.
SCATTERED DIURNAL CLOUDS AROUND 3500 FEET DEVELOPING MID-MORNING
AND FADING OFF TOWARD SUNSET.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1136 PM CDT WED JUL 17 2013
.DISCUSSION...
ISSUED 830 PM CDT WED JUL 17 2013
LAST OF THE DIURNAL CUMULUS HAS FADED...WITH SOME HIGH CLOUDS
MOVING INTO THE FAR SOUTHEAST CWA FROM SOME CONVECTION ALONG THE
OHIO VALLEY. HIGH PRESSURE SITTING OVER CHAMPAIGN WILL KEEP WINDS
LIGHT TO CALM OVERNIGHT...WITH SKIES MAINLY CLEAR ASIDE FROM THE
CIRRUS PREVIOUSLY MENTIONED. TEMPERATURES A LITTLE SLOW TO DROP
OFF SO FAR...BUT THINK THAT LOWER 70S STILL LOOKS GOOD OVER MOST
OF THE AREA FOR LOWS TONIGHT. HAVE SENT SOME GRID UPDATES TO
REFLECT THE LATEST TRENDS...BUT NO CHANGES NEEDED TO THE WORDED
FORECASTS.
GEELHART
&&
.AVIATION...
ISSUED 1135 PM CDT WED JUL 17 2013
MAIN CONCERN REMAINS WITH MVFR CONDITIONS WITH LIGHT FOG
OVERNIGHT. HAVE BEEN SEEING VISIBILITIES LOWERING TO AROUND 7SM
ALREADY NEAR THE INDIANA BORDER AND CREEPING NORTHWEST...AND WINDS
ARE BASICALLY CALM. KBMI IS THE ONLY ONE THAT HAS SEEN DECENT
RAINFALL OVER THE LAST COUPLE DAYS WHICH WILL ADD MOISTURE TO THE
AIR...AND STILL THINK THEY WILL BE THE MOST LIKELY TO SEE MVFR
CONDITIONS. LATEST RAP MODEL FOCUSES THE THICKEST FOG JUST SOUTH
OF KCMI/KDEC...AND WILL MAINTAIN THE TEMPO PERIODS OF LIGHT FOG.
DAYTIME HOURS ON THURSDAY WILL BE SIMILAR TO WEDNESDAY...I.E.
SCATTERED DIURNAL CLOUDS AROUND 3500 FEET DEVELOPING MID-MORNING
AND FADING OFF TOWARD SUNSET.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 258 PM CDT WED JUL 17 2013
DOME OF HIGH PRESSURE BRINGING STIFLING HEAT TO ILLINOIS SHOULD
BREAK DOWN BY THE END OF THE WEEK ALLOWING A RETURN TO NORTHWEST
FLOW AND COOLER TEMPS.
SHORT TERM...TONIGHT THROUGH FRIDAY
597 DM RIDGE REMAINS ENTRENCHED OVER ILLINOIS TODAY LEADING TO
VERY WARM TEMPERATURES AND LIGHT WINDS. HEAT INDEX VALUES HAVE
TOPPED OFF NEAR 100 DEGREES AT MOST LOCATIONS AND LOOKS LIKE
SIMILAR CONDITIONS ARE LIKELY THROUGH FRIDAY. A FRONT BEGINS TO
APPROACH FROM THE NORTH ON FRIDAY AS SHORT WAVES EAT AWAY AT MID-
LEVEL RIDGE. ENOUGH RESIDUAL WARM DRY AIR ALOFT SHOULD BE IN PLACE
FRIDAY TO KEEP CAP IN PLACE PER NAM WRF. MOISTURE WILL LIKELY POOL
AHEAD OF THE BOUNDARY...BUT GFS HAS OVERESTIMATED DEW POINTS PAST
FEW DAYS AND WITH GULF MOISTURE CUTOFF LIKE DRIER NAM. INCREASE IN
POOLING BOUNDARY LAYER MOISTURE WILL LIKELY LEAD TO INCREASE IN
HEAT INDEX FOR FRIDAY. FORECAST VALUES ARE CURRENTLY BELOW HEAT
ADVISORY CRITERIA...BUT WITH MULTIPLE DAYS NEAR 100 OR ABOVE LATER
SHIFTS MAY NEED TO REVISIT ISSUING.
LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY
TRANSITION TO NORTHWEST FLOW ALOFT CONTINUES OVER THE WEEKEND AS
500 DM HEIGHT FALLS ABOUT 150 METERS BETWEEN NOW AND 00Z SUNDAY.
HEIGHT FALLS SHOULD BE SUFFICIENT TO PUSH FRONT THROUGH FORECAST AREA
LATE FRIDAY NIGHT AND SATURDAY. CONVERGENCE ALONG FRONT MAY BE
SUFFICIENT TO BREAK CAP SO WILL INCLUDE CHC POPS IN THE VICINITY
OF THE BOUNDARY. ECMWF DROPS 850 TEMPS 5-7C/24 HOURS BY SATURDAY
EVENING WHICH SHOULD BRING OUR HIGH TEMPS 10-15 DEGREES COOLER FOR
SATURDAY...PARTICULARLY WITH ANY RESIDUAL CLOUDS FOLLOWING FRONTAL
PASSAGE.
BY LATE SUNDAY NORTHWEST FLOW ALOFT IS FIRMLY ESTABLISHED AND WEAK
SHORTWAVES ARE PASSING THROUGH THE FLOW. THERE ARE INDICATIONS
THAT SEVERAL OF THESE WAVES WILL PROVIDE ENOUGH LIFT FOR POTENTIAL
CONVECTION. HOWEVER...THE MAIN QUESTION IS HOW MUCH MOISTURE WILL
BE AVAILABLE TO TAP WHICH WILL DETERMINE THE COVERAGE AND
INTENSITY OF CONVECTIVE EVENTS. TIMING IS ALSO AN ISSUE AS IT
OFTEN IS WITH WEAK SHORTWAVES MOVING THROUGH NORTHWEST FLOW. BEST
WE CAN DO AT THIS POINT IS TO INTRODUCE LOW CHC POPS SUNDAY NIGHT
AND THEN KEEP THEM GOING THROUGH THE FIRST PART OF THE WEEK.
TEMPS SHOULD REMAIN NEAR TO SLIGHTLY BELOW NORMAL WITH OCCASIONAL
PERIODS OF CLOUDS KEEPING TEMPS DOWN A BIT.
BARKER
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
427 AM EDT THU JUL 18 2013
.UPDATE...
AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 346 AM EDT THU JUL 18 2013
HOT AND HUMID WEATHER WILL CONTINUE THROUGH FRIDAY AS THE RIDGE
ALOFT GRADUALLY SHIFTS TO THE SOUTH. A VIGOROUS UPPER LEVEL LOW WILL
TRACK THROUGH EASTERN CANADA WITH A COLD FRONT TRACKING SOUTH INTO
THE REGION ON SATURDAY. THE ARRIVAL AND PASSAGE OF THE FRONT WILL
BRING NUMEROUS SHOWERS AND THUNDERSTORMS TO CENTRAL INDIANA LATE
FRIDAY NIGHT THROUGH SATURDAY EVENING. COOLER DRIER AIR WILL BRIEFLY
BUILD INTO THE REGION ON SUNDAY AS HIGH PRESSURE PASSES THROUGH THE
GREAT LAKES. CHANCES FOR THUNDERSTORMS WILL RETURN BY LATE SUNDAY
NIGHT AND MONDAY AND CONTINUE THROUGH THE MIDDLE OF NEXT WEEK AS THE
FRONTAL BOUNDARY DRIFTS BACK NORTH INTO THE AREA.
&&
.NEAR TERM /TODAY/...
ISSUED AT 346 AM EDT THU JUL 18 2013
ANOTHER MUGGY START EARLY THIS MORNING AS 07Z TEMPS GENERALLY IN THE
MID AND UPPER 70S. CONVECTIVE DEBRIS CLOUDS CONTINUE TO DRIFT INTO
THE SOUTHERN HALF OF THE FORECAST AREA AS A WEAK UPPER WAVE
CURRENTLY TRACKS ACROSS THE TENNESSEE VALLEY.
THE UPPER LEVEL HIGH REMAINS PARKED ACROSS CENTRAL INDIANA WITH MID
LEVEL HEIGHT MAXES STILL AROUND 597DAM. THESE HEIGHTS WILL SLOWLY
FALL THROUGH THE DAY AS THE RIDGE GRADUALLY BUCKLES IN RESPONSE TO A
DEVELOPING STRONG UPPER LOW GETTING ITS ACT TOGETHER ACROSS JAMES
BAY. THE AFOREMENTIONED WEAK WAVE ALOFT OVER THE TENNESSEE VALLEY
WILL DRIFT WEST THROUGH THE DAY AND SHOULD BE LOCATED OVER THE LOWER
OHIO VALLEY BY LATE DAY. SCATTERED CONVECTION ASSOCIATED WITH THIS
FEATURE SHOULD DEVELOP ACROSS KENTUCKY AND TENNESSEE AND MAY EVEN
SEE A FEW STORMS MAKE IT INTO OUR SOUTHERN COUNTIES. THE HRRR LOOKS
TO BE OVERDOING CONVECTIVE DEVELOPMENT IN GENERAL BUT HINTS AT THIS
IDEA AS WELL. CONSIDERING THE NATURE OF THE AIRMASS AND THE
PROXIMITY OF THE UPPER WAVE...ISOLATED POPS ARE WARRANTED ACROSS FAR
SOUTHERN COUNTIES FOR THIS AFTERNOON. FURTHER NORTH DESPITE THE
GRADUALLY LOWERING MID LEVEL HEIGHTS...THE RIDGING ALOFT AND CAP
NEAR 650MB ARE LIKELY TO REMAIN TOO STRONG FOR ANY SUBSTANTIAL
CONVECTIVE DEVELOPMENT. WHILE AN ISOLATED SHOWER CANNOT BE RULED
OUT...COVERAGE LIKELY TO BE SO LOW TO PRECLUDE ANY MENTION IN THE
FORECAST AT THIS TIME.
TEMPS...LOW LEVEL THERMALS WILL BE SIMILAR TO WEDNESDAY WITH 850MB
TEMPS RISING TO AROUND 19-20C. LIKEWISE EXPECT HIGH TEMPS TO BE
SIMILAR TO WEDNESDAY AS WELL...REACHING THE 92-94 DEGREE RANGE FOR
MUCH OF THE FORECAST AREA. GENERALLY GOING A DEGREE OR TWO ABOVE
MOS. MAX HEAT INDICES WILL RISE TO AROUND 100 DEGREES AGAIN THIS
AFTERNOON...AND MAY TOP OUT JUST A TOUCH WARMER THAN WEDNESDAY AS
SLIGHTLY DEEPER MOISTURE IS PULLED NORTH INTO THE REGION. HAVE NO
PLANS TO INTRODUCE A HEAT ADVISORY AS THESE VALUES REMAINS BELOW
CRITERIA. WILL CONTINUE WITH THE SPS.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 346 AM EDT THU JUL 18 2013
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES AND TEMPS AS A COLD
FRONT DROPS SOUTH THROUGH THE REGION SATURDAY. MODELS GENERALLY IN
VERY GOOD AGREEMENT ON MAIN FEATURES THROUGHOUT THE SHORT TERM.
RIDGING ALOFT WILL CONTINUE TO SINK SOUTH AND FLATTEN AS THE DEEP
UPPER LOW DIVES ACROSS NORTHERN ONTARIO...THEN PINWHEELS INTO THE
CANADIAN MARITIMES BY SUNDAY MORNING. ROBUST CONVECTIVE DEVELOPMENT
WILL TAKE PLACE TONIGHT OVER THE UPPER MISSISSIPPI VALLEY AND
NORTHERN GREAT LAKES IN PROXIMITY TO THE COLD FRONT. THIS FRONT WILL
SINK SOUTH AND SHOULD BE LOCATED ACROSS THE WESTERN GREAT LAKES BY
FRIDAY AFTERNOON. THE FLATTENING OF THE RIDGE AND APPROACH OF THE
COLD FRONT WILL ENCOURAGE A W/SW FLOW THROUGH THE LOWER LEVELS ON
FRIDAY...WITH POTENTIAL FOR SOME GUSTS TO NEAR 20-25KTS OVER
NORTHERN COUNTIES BY AFTERNOON AS A LOW LEVEL JET ACCOMPANIES THE
BOUNDARY THROUGH THE GREAT LAKES. WILL MAINTAIN LOW CHANCE POPS FOR
ISOLATED CONVECTIVE DEVELOPMENT FRIDAY AFTERNOON...BUT ANTICIPATE IT
WILL BE MORE FOCUSED OVER THE SOUTHERN HALF OF THE FORECAST AREA
WHERE DEEPER MOISTURE WILL RESIDE. THE W/SW FLOW WILL DRAW A SLUG OF
DRIER AIR ALOFT INTO THE LOWER GREAT LAKES IMMEDIATELY AHEAD OF THE
FRONT THAT WILL GRADUALLY BECOME SQUEEZED BY MOISTURE ADVECTING NORTH
AROUND THE BACK SIDE OF THE BERMUDA HIGH AND MOISTURE POOLING ALONG
THE BOUNDARY. THIS MAY LIMIT CONVECTIVE DEVELOPMENT OVER NORTHERN
COUNTIES FOR MUCH OF THE DAY.
FOCUS WILL SHIFT TO THE N/NW OF THE REGION BY LATE FRIDAY AFTERNOON
AS CONVECTION IS LIKELY TO DEVELOP IN THE VICINITY OF THE BOUNDARY
AND QUICKLY BECOME SEVERE AS BL SHEAR VALUES ARE ENHANCED AND
AIRMASS WILL BE MODERATELY UNSTABLE. STORMS ARE LIKELY TO ORGANIZE
INTO A MESOSCALE CONVECTIVE COMPLEX BY FRIDAY EVENING WITH
THERMODYNAMIC PROFILES SUGGESTING THE POTENTIAL FOR A SIGNIFICANT
DAMAGING WIND THREAT AS THE STORMS MOVE ACROSS THE LOWER GREAT
LAKES. THIS CONVECTION SHOULD LARGELY REMAIN TO THE NORTH OF THE
FORECAST AREA THROUGH THE EVENING...WITH PRECIP CHANCES RISING AFTER
MIDNIGHT AS THE TAIL END OF THE COMPLEX SAGS SOUTH INTO THE REGION
WITH THE COLD FRONT. AT THIS POINT...THERE IS GREATER UNCERTAINTY AS
TO THE POTENTIAL FOR CONVECTION TO MAINTAIN ITS INTENSITY OVER THE
FORECAST AREA LATE FRIDAY NIGHT. THE CORE OF THE COMPLEX IS EXPECTED
TO TRACK ACROSS THE LOWER GREAT LAKES IN CLOSER PROXIMITY TO THE
DEEPER FORCING ALOFT AND THE LOCATION OF THE LOW LEVEL JET. THE
COMPLEX IS LIKELY TO DROP A WELL DEFINED COLD POOL AND THERE IS A
POSSIBILITY THAT THIS COULD WORK INTO NORTHERN PORTIONS OF THE
FORECAST AREA BEFORE WEAKENING. AT THIS POINT...ANTICIPATE A
WEAKENING LINE OF STORMS IMPACTING THE FORECAST AREA LATE FRIDAY
NIGHT WITH THE POTENTIAL FOR STORMS TO PRODUCE DAMAGING WINDS.
THE FRONT WILL SLOW DOWN ITS FORWARD PROGRESS AS IT RUNS INTO THE
SUPPRESSED RIDGE TO OUR SOUTH. BOUNDARY LIKELY TO TAKE ALL DAY
SATURDAY AND LIKELY A PORTION OF SATURDAY NIGHT TO MOVE ACROSS THE
FORECAST AREA. LEFTOVER CONVECTION FROM FRIDAY NIGHT MAY BE ONGOING
IN A WEAKENED STATE SATURDAY MORNING...BUT EXPECT RENEWED
DEVELOPMENT THROUGHOUT THE DAY. PRECIP WATER VALUES NEAR 2
INCHES...LOW LEVEL CONVERGENCE IN VICINITY OF THE FRONT AND MODEST
INSTABILITY WILL BE THE MAIN CATALYSTS FOR CONVECTIVE DEVELOPMENT
AND INTENSITY AS DEEPER FORCING ALOFT WILL BE FOCUSED FURTHER TO THE
NORTHEAST OVER THE EASTERN GREAT LAKES AND INTO NEW ENGLAND. WHILE
STORMS WILL HAVE THE POTENTIAL TO PRODUCE DAMAGING WINDS...NOT
EXPECTING A WIDESPREAD SEVERE THREAT IN THE ABSENCE OF DEEPER SHEAR
AND BETTER FORCING ALOFT. POTENTIAL FOR HEAVY RAINFALL AND LOCALIZED
FLOODING WITH THE HIGH PWATS. WILL CARRY HIGH CHANCE/LIKELY POPS
SATURDAY...WITH PRECIP CHANCES ENDING LATE SATURDAY NIGHT AS THE
FRONT SETTLES NEAR THE OHIO RIVER.
TEMPS...SEVERAL FACTORS SUGGESTIVE THAT FRIDAY COULD BE THE HOTTEST
DAY OF THIS RECENT STRETCH OF HOT DAYS FOR MUCH OF THE FORECAST AREA.
850MB TEMPS RISE TO 20-21C AND COMBINED WITH THE STRONGER W/SW FLOW
WHICH SHOULD ENHANCE BOUNDARY LAYER MIXING AND COMPRESSIONAL HEATING
AHEAD OF THE FRONT...COULD VERY WELL SEE TEMPS MAX OUT AT 94-95 IN
SOME LOCATIONS. MOS GUIDANCE LOOKS FAR TOO COOL AND WILL GENERALLY
BE 2-3 DEGREES WARMER. MOS GUIDANCE WITH HIGHS MAINLY IN THE UPPER
80S LOOKED REASONABLE FOR SATURDAY WITH STORMS AND INCREASED CLOUD
COVERAGE. LOWS WILL REMAIN IN THE 70S TONIGHT AND FRIDAY NIGHT...
FALLING BACK INTO THE 60S SATURDAY NIGHT AS COOLER DRIER AIR EXPANDS
SOUTH BEHIND THE FRONT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 305 AM EDT THU JUL 18 2013
TEMPERATURES WILL NOT BE QUITE AS HOT DURING THE LONG TERM AS THE
UPPER HIGH WILL BE OVER THE WESTERN U.S. AND HEIGHTS LOWER A LITTLE
ACROSS THE GREAT LAKES. A WEAK COLD FRONT WILL STALL ACROSS THE
GREAT LAKES SUNDAY AS HIGH PRESSURE MOVES EAST ACROSS THE GREAT
LAKES. ALL AREAS SHOULD REMAIN DRY UNDER THIS SITUATION SUNDAY.
AFTER SUNDAY WILL MENTION CHANCE POPS FROM LATE SUNDAY NIGHT THROUGH
DAY 7 AS A SERIES OF WEAK DISTURBANCES MOVE EAST ALONG THIS STALLED
FRONT. THERE IS SOME DISCREPANCY ON TIMING OF THESE DISTURBANCES
BETWEEN THE DIFFERENT MODELS. HOWEVER MODEL CONSENSUS SEEMS TO POINT
TOWARDS ONE OF THE MAIN DISTURBANCES MOVING THROUGH AROUND MONDAY
AND ANOTHER ONE EITHER MOVING ACROSS OUR REGION TUESDAY NIGHT OR
WEDNESDAY.
CUT ALL BLEND POPS A LITTLE SUNDAY AND SUNDAY EVENING.
OTHERWISE...I DID NOT MAKE ANY SIGNIFICANT CHANGES TO POPS OR
TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR THE 180900Z KIND TAF UPDATE/...
ISSUED AT 427 AM EDT THU JUL 18 2013
MINOR TWEAKS MADE TO KIND TAF TO BETTER MATCH CURRENT CONDITIONS. NO
OTHER CHANGES NEEDED AT THIS TIME. PREVIOUS AVIATION DISCUSSION
FOLLOWS...
ASIDE FROM SOME OVERNIGHT MVFR VSBYS AT LAF/HUF/BMG...VFR CONDITIONS
ARE EXPECTED DURING THIS TAF CYCLE.
CONVECTION THAT OCCURRED OVER FAR SOUTHERN INDIANA AS WELL AS
NORTHERN/CENTRAL KENTUCKY WEDNESDAY EVENING HAS DISSIPATED AND ITS
ASSOCIATED MID/UPPER CLOUD COVER THAT WAS INITIALLY PRESSING
NORTHWARD IS CONTINUING TO ERODE ON THE NORTHERN EDGE.
PERSISTENCE FORECAST CONTINUES AS CONDITIONS REMAIN SIMILAR TO LAST
NIGHT WITH THE UPPER RIDGE OVERHEAD. THUS...FOG FORMATION CONTINUES
TO BE THE MAIN ISSUE. LIGHT WINDS WILL PERSIST OVERNIGHT AS SURFACE
HIGH PRESSURE REMAINS IN CONTROL. COUPLE THAT WITH DEWPOINT
DEPRESSIONS ALREADY LESS THAN OR EQUAL TO 5 DEGREES AT
LAF/HUF/BMG...CANNOT RULE OUT A REPEAT OF LAST NIGHT OR CLOSE TO IT.
THUS...HAVE KEPT THE MVFR CONDITIONS GOING FOR LAF/HUF/BMG
TONIGHT...UNTIL 12/13Z THURSDAY. NO MENTION CURRENTLY OF ANY BRIEF
IFR VSBYS AT LAF/HUF/BMG...BUT WOULD NOT RULE IT OUT BETWEEN 08Z TO
11Z. EXPECT CU TO DEVELOP OVER THE AREA AGAIN LATE TOMORROW MORNING
WITH BASES AOA 4 KFT. WINDS WILL REMAIN UNDER 10 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....JH
AVIATION...MRD/JH
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
346 AM EDT THU JUL 18 2013
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED
BELOW.
&&
.SYNOPSIS...
ISSUED AT 346 AM EDT THU JUL 18 2013
HOT AND HUMID WEATHER WILL CONTINUE THROUGH FRIDAY AS THE RIDGE
ALOFT GRADUALLY SHIFTS TO THE SOUTH. A VIGOROUS UPPER LEVEL LOW WILL
TRACK THROUGH EASTERN CANADA WITH A COLD FRONT TRACKING SOUTH INTO
THE REGION ON SATURDAY. THE ARRIVAL AND PASSAGE OF THE FRONT WILL
BRING NUMEROUS SHOWERS AND THUNDERSTORMS TO CENTRAL INDIANA LATE
FRIDAY NIGHT THROUGH SATURDAY EVENING. COOLER DRIER AIR WILL BRIEFLY
BUILD INTO THE REGION ON SUNDAY AS HIGH PRESSURE PASSES THROUGH THE
GREAT LAKES. CHANCES FOR THUNDERSTORMS WILL RETURN BY LATE SUNDAY
NIGHT AND MONDAY AND CONTINUE THROUGH THE MIDDLE OF NEXT WEEK AS THE
FRONTAL BOUNDARY DRIFTS BACK NORTH INTO THE AREA.
&&
.NEAR TERM /TODAY/...
ISSUED AT 346 AM EDT THU JUL 18 2013
ANOTHER MUGGY START EARLY THIS MORNING AS 07Z TEMPS GENERALLY IN THE
MID AND UPPER 70S. CONVECTIVE DEBRIS CLOUDS CONTINUE TO DRIFT INTO
THE SOUTHERN HALF OF THE FORECAST AREA AS A WEAK UPPER WAVE
CURRENTLY TRACKS ACROSS THE TENNESSEE VALLEY.
THE UPPER LEVEL HIGH REMAINS PARKED ACROSS CENTRAL INDIANA WITH MID
LEVEL HEIGHT MAXES STILL AROUND 597DAM. THESE HEIGHTS WILL SLOWLY
FALL THROUGH THE DAY AS THE RIDGE GRADUALLY BUCKLES IN RESPONSE TO A
DEVELOPING STRONG UPPER LOW GETTING ITS ACT TOGETHER ACROSS JAMES
BAY. THE AFOREMENTIONED WEAK WAVE ALOFT OVER THE TENNESSEE VALLEY
WILL DRIFT WEST THROUGH THE DAY AND SHOULD BE LOCATED OVER THE LOWER
OHIO VALLEY BY LATE DAY. SCATTERED CONVECTION ASSOCIATED WITH THIS
FEATURE SHOULD DEVELOP ACROSS KENTUCKY AND TENNESSEE AND MAY EVEN
SEE A FEW STORMS MAKE IT INTO OUR SOUTHERN COUNTIES. THE HRRR LOOKS
TO BE OVERDOING CONVECTIVE DEVELOPMENT IN GENERAL BUT HINTS AT THIS
IDEA AS WELL. CONSIDERING THE NATURE OF THE AIRMASS AND THE
PROXIMITY OF THE UPPER WAVE...ISOLATED POPS ARE WARRANTED ACROSS FAR
SOUTHERN COUNTIES FOR THIS AFTERNOON. FURTHER NORTH DESPITE THE
GRADUALLY LOWERING MID LEVEL HEIGHTS...THE RIDGING ALOFT AND CAP
NEAR 650MB ARE LIKELY TO REMAIN TOO STRONG FOR ANY SUBSTANTIAL
CONVECTIVE DEVELOPMENT. WHILE AN ISOLATED SHOWER CANNOT BE RULED
OUT...COVERAGE LIKELY TO BE SO LOW TO PRECLUDE ANY MENTION IN THE
FORECAST AT THIS TIME.
TEMPS...LOW LEVEL THERMALS WILL BE SIMILAR TO WEDNESDAY WITH 850MB
TEMPS RISING TO AROUND 19-20C. LIKEWISE EXPECT HIGH TEMPS TO BE
SIMILAR TO WEDNESDAY AS WELL...REACHING THE 92-94 DEGREE RANGE FOR
MUCH OF THE FORECAST AREA. GENERALLY GOING A DEGREE OR TWO ABOVE
MOS. MAX HEAT INDICES WILL RISE TO AROUND 100 DEGREES AGAIN THIS
AFTERNOON...AND MAY TOP OUT JUST A TOUCH WARMER THAN WEDNESDAY AS
SLIGHTLY DEEPER MOISTURE IS PULLED NORTH INTO THE REGION. HAVE NO
PLANS TO INTRODUCE A HEAT ADVISORY AS THESE VALUES REMAINS BELOW
CRITERIA. WILL CONTINUE WITH THE SPS.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 346 AM EDT THU JUL 18 2013
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES AND TEMPS AS A COLD
FRONT DROPS SOUTH THROUGH THE REGION SATURDAY. MODELS GENERALLY IN
VERY GOOD AGREEMENT ON MAIN FEATURES THROUGHOUT THE SHORT TERM.
RIDGING ALOFT WILL CONTINUE TO SINK SOUTH AND FLATTEN AS THE DEEP
UPPER LOW DIVES ACROSS NORTHERN ONTARIO...THEN PINWHEELS INTO THE
CANADIAN MARITIMES BY SUNDAY MORNING. ROBUST CONVECTIVE DEVELOPMENT
WILL TAKE PLACE TONIGHT OVER THE UPPER MISSISSIPPI VALLEY AND
NORTHERN GREAT LAKES IN PROXIMITY TO THE COLD FRONT. THIS FRONT WILL
SINK SOUTH AND SHOULD BE LOCATED ACROSS THE WESTERN GREAT LAKES BY
FRIDAY AFTERNOON. THE FLATTENING OF THE RIDGE AND APPROACH OF THE
COLD FRONT WILL ENCOURAGE A W/SW FLOW THROUGH THE LOWER LEVELS ON
FRIDAY...WITH POTENTIAL FOR SOME GUSTS TO NEAR 20-25KTS OVER
NORTHERN COUNTIES BY AFTERNOON AS A LOW LEVEL JET ACCOMPANIES THE
BOUNDARY THROUGH THE GREAT LAKES. WILL MAINTAIN LOW CHANCE POPS FOR
ISOLATED CONVECTIVE DEVELOPMENT FRIDAY AFTERNOON...BUT ANTICIPATE IT
WILL BE MORE FOCUSED OVER THE SOUTHERN HALF OF THE FORECAST AREA
WHERE DEEPER MOISTURE WILL RESIDE. THE W/SW FLOW WILL DRAW A SLUG OF
DRIER AIR ALOFT INTO THE LOWER GREAT LAKES IMMEDIATELY AHEAD OF THE
FRONT THAT WILL GRADUALLY BECOME SQUEEZED BY MOISTURE ADVECTING NORTH
AROUND THE BACK SIDE OF THE BERMUDA HIGH AND MOISTURE POOLING ALONG
THE BOUNDARY. THIS MAY LIMIT CONVECTIVE DEVELOPMENT OVER NORTHERN
COUNTIES FOR MUCH OF THE DAY.
FOCUS WILL SHIFT TO THE N/NW OF THE REGION BY LATE FRIDAY AFTERNOON
AS CONVECTION IS LIKELY TO DEVELOP IN THE VICINITY OF THE BOUNDARY
AND QUICKLY BECOME SEVERE AS BL SHEAR VALUES ARE ENHANCED AND
AIRMASS WILL BE MODERATELY UNSTABLE. STORMS ARE LIKELY TO ORGANIZE
INTO A MESOSCALE CONVECTIVE COMPLEX BY FRIDAY EVENING WITH
THERMODYNAMIC PROFILES SUGGESTING THE POTENTIAL FOR A SIGNIFICANT
DAMAGING WIND THREAT AS THE STORMS MOVE ACROSS THE LOWER GREAT
LAKES. THIS CONVECTION SHOULD LARGELY REMAIN TO THE NORTH OF THE
FORECAST AREA THROUGH THE EVENING...WITH PRECIP CHANCES RISING AFTER
MIDNIGHT AS THE TAIL END OF THE COMPLEX SAGS SOUTH INTO THE REGION
WITH THE COLD FRONT. AT THIS POINT...THERE IS GREATER UNCERTAINTY AS
TO THE POTENTIAL FOR CONVECTION TO MAINTAIN ITS INTENSITY OVER THE
FORECAST AREA LATE FRIDAY NIGHT. THE CORE OF THE COMPLEX IS EXPECTED
TO TRACK ACROSS THE LOWER GREAT LAKES IN CLOSER PROXIMITY TO THE
DEEPER FORCING ALOFT AND THE LOCATION OF THE LOW LEVEL JET. THE
COMPLEX IS LIKELY TO DROP A WELL DEFINED COLD POOL AND THERE IS A
POSSIBILITY THAT THIS COULD WORK INTO NORTHERN PORTIONS OF THE
FORECAST AREA BEFORE WEAKENING. AT THIS POINT...ANTICIPATE A
WEAKENING LINE OF STORMS IMPACTING THE FORECAST AREA LATE FRIDAY
NIGHT WITH THE POTENTIAL FOR STORMS TO PRODUCE DAMAGING WINDS.
THE FRONT WILL SLOW DOWN ITS FORWARD PROGRESS AS IT RUNS INTO THE
SUPPRESSED RIDGE TO OUR SOUTH. BOUNDARY LIKELY TO TAKE ALL DAY
SATURDAY AND LIKELY A PORTION OF SATURDAY NIGHT TO MOVE ACROSS THE
FORECAST AREA. LEFTOVER CONVECTION FROM FRIDAY NIGHT MAY BE ONGOING
IN A WEAKENED STATE SATURDAY MORNING...BUT EXPECT RENEWED
DEVELOPMENT THROUGHOUT THE DAY. PRECIP WATER VALUES NEAR 2
INCHES...LOW LEVEL CONVERGENCE IN VICINITY OF THE FRONT AND MODEST
INSTABILITY WILL BE THE MAIN CATALYSTS FOR CONVECTIVE DEVELOPMENT
AND INTENSITY AS DEEPER FORCING ALOFT WILL BE FOCUSED FURTHER TO THE
NORTHEAST OVER THE EASTERN GREAT LAKES AND INTO NEW ENGLAND. WHILE
STORMS WILL HAVE THE POTENTIAL TO PRODUCE DAMAGING WINDS...NOT
EXPECTING A WIDESPREAD SEVERE THREAT IN THE ABSENCE OF DEEPER SHEAR
AND BETTER FORCING ALOFT. POTENTIAL FOR HEAVY RAINFALL AND LOCALIZED
FLOODING WITH THE HIGH PWATS. WILL CARRY HIGH CHANCE/LIKELY POPS
SATURDAY...WITH PRECIP CHANCES ENDING LATE SATURDAY NIGHT AS THE
FRONT SETTLES NEAR THE OHIO RIVER.
TEMPS...SEVERAL FACTORS SUGGESTIVE THAT FRIDAY COULD BE THE HOTTEST
DAY OF THIS RECENT STRETCH OF HOT DAYS FOR MUCH OF THE FORECAST AREA.
850MB TEMPS RISE TO 20-21C AND COMBINED WITH THE STRONGER W/SW FLOW
WHICH SHOULD ENHANCE BOUNDARY LAYER MIXING AND COMPRESSIONAL HEATING
AHEAD OF THE FRONT...COULD VERY WELL SEE TEMPS MAX OUT AT 94-95 IN
SOME LOCATIONS. MOS GUIDANCE LOOKS FAR TOO COOL AND WILL GENERALLY
BE 2-3 DEGREES WARMER. MOS GUIDANCE WITH HIGHS MAINLY IN THE UPPER
80S LOOKED REASONABLE FOR SATURDAY WITH STORMS AND INCREASED CLOUD
COVERAGE. LOWS WILL REMAIN IN THE 70S TONIGHT AND FRIDAY NIGHT...
FALLING BACK INTO THE 60S SATURDAY NIGHT AS COOLER DRIER AIR EXPANDS
SOUTH BEHIND THE FRONT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 305 AM EDT THU JUL 18 2013
TEMPERATURES WILL NOT BE QUITE AS HOT DURING THE LONG TERM AS THE
UPPER HIGH WILL BE OVER THE WESTERN U.S. AND HEIGHTS LOWER A LITTLE
ACROSS THE GREAT LAKES. A WEAK COLD FRONT WILL STALL ACROSS THE
GREAT LAKES SUNDAY AS HIGH PRESSURE MOVES EAST ACROSS THE GREAT
LAKES. ALL AREAS SHOULD REMAIN DRY UNDER THIS SITUATION SUNDAY.
AFTER SUNDAY WILL MENTION CHANCE POPS FROM LATE SUNDAY NIGHT THROUGH
DAY 7 AS A SERIES OF WEAK DISTURBANCES MOVE EAST ALONG THIS STALLED
FRONT. THERE IS SOME DISCREPANCY ON TIMING OF THESE DISTURBANCES
BETWEEN THE DIFFERENT MODELS. HOWEVER MODEL CONSENSUS SEEMS TO POINT
TOWARDS ONE OF THE MAIN DISTURBANCES MOVING THROUGH AROUND MONDAY
AND ANOTHER ONE EITHER MOVING ACROSS OUR REGION TUESDAY NIGHT OR
WEDNESDAY.
CUT ALL BLEND POPS A LITTLE SUNDAY AND SUNDAY EVENING.
OTHERWISE...I DID NOT MAKE ANY SIGNIFICANT CHANGES TO POPS OR
TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR THE 180600Z TAF ISSUANCE/...
ISSUED AT 1236 AM EDT THU JUL 18 2013
ASIDE FROM SOME OVERNIGHT MVFR VSBYS AT LAF/HUF/BMG...VFR CONDITIONS
ARE EXPECTED DURING THIS TAF CYCLE.
CONVECTION THAT OCCURRED OVER FAR SOUTHERN INDIANA AS WELL AS
NORTHERN/CENTRAL KENTUCKY WEDNESDAY EVENING HAS DISSIPATED AND ITS
ASSOCIATED MID/UPPER CLOUD COVER THAT WAS INITIALLY PRESSING
NORTHWARD IS CONTINUING TO ERODE ON THE NORTHERN EDGE.
PERSISTENCE FORECAST CONTINUES AS CONDITIONS REMAIN SIMILAR TO LAST
NIGHT WITH THE UPPER RIDGE OVERHEAD. THUS...FOG FORMATION CONTINUES
TO BE THE MAIN ISSUE. LIGHT WINDS WILL PERSIST OVERNIGHT AS SURFACE
HIGH PRESSURE REMAINS IN CONTROL. COUPLE THAT WITH DEWPOINT
DEPRESSIONS ALREADY LESS THAN OR EQUAL TO 5 DEGREES AT
LAF/HUF/BMG...CANNOT RULE OUT A REPEAT OF LAST NIGHT OR CLOSE TO IT.
THUS...HAVE KEPT THE MVFR CONDITIONS GOING FOR LAF/HUF/BMG
TONIGHT...UNTIL 12/13Z THURSDAY. NO MENTION CURRENTLY OF ANY BRIEF
IFR VSBYS AT LAF/HUF/BMG...BUT WOULD NOT RULE IT OUT BETWEEN 08Z TO
11Z. EXPECT CU TO DEVELOP OVER THE AREA AGAIN LATE TOMORROW MORNING
WITH BASES AOA 4 KFT. WINDS WILL REMAIN UNDER 10 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....JH
AVIATION...MRD/JH
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WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
148 AM EDT THU JUL 18 2013
.UPDATE...
ISSUED AT 1038 PM EDT WED JUL 17 2013
THE FRONTAL BOUNDARY IS BASICALLY RIGHT OVER THE AREA. SCATTERED
SHOWERS AND THUNDERSTORMS DEVELOPED THIS AFTERNOON HELPED BY THE
UNSTABLE AIRMASS AND LAKE BREEZE BOUNDARIES. NOW...SHOWERS AND
THUNDERSTORMS HAVE ONCE AGAIN DEVELOPED AND FOCUSED MORE ON THE MAIN
FRONTAL BOUNDARY. THIS ACTIVITY EXTENDS FROM UPPER MICHIGAN WEST
INTO NRN MN. THE MAIN CONCERN IN THE UPDATE IS THE EVOLUTION OF
CONVECTION OVERNIGHT. SOME OF THE RAPID UPDATE MODELS INCLUDING THE
LOCAL RUNS OF THE WRF BASED ON THE RAP...SUGGEST THAT AS THE 850MB
FLOW BACKS TONIGHT AND STRENGTHENS OVER MN...AN MCS TYPE FEATURE
WILL DEVELOP AND TRACK ALONG THE 850MB THERMAL GRADIENT.
MEANWHILE...THE NAM AND THE HRRR SUGGEST THAT MULTICELL ACTIVITY
WILL CONTINUE ALONG THE FRONT AND TRACK OVER UPPER MICHIGAN
TONIGHT...ESPECIALLY LATE AS THE LOW LEVEL JET NOSES INTO THE AREA.
LOOKING AT THE LATEST RADAR TRENDS AND LACK OF ANY SIGNIFICANT
CONVECTIVE CLOUD DEVELOPMENT SOUTH OF THE FRONT...TEND TO BELIEVE
THE SCENARIO OF MORE MULTICELL DEVELOPMENT WITH SCATTERED-NUMEROUS
SHOWERS AND STORMS CONTINUING ALL NIGHT ESPECIALLY ACROSS THE WEST
HALF NEAR THE FRONTAL BOUNDARY. MOST LIKELY THE MAIN CONCERN TONIGHT
WILL BE THE HEAVY RAINFALL GIVEN THE HIGH FREEZING LEVELS ABOVE
15KFT AND PRECIPITABLE WATER VALUES ABOVE 2 INCHES...ALTHOUGH IF
SOME ORGANIZATION OF CONVECTION CAN OCCUR...UNIDIRECTIONAL EFFECTIVE
SHEAR VALUES OF 30-40KT WOULD SUGGEST A POTENTIAL WIND THREAT IF A
COLD POOL COULD DEVELOP.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 432 PM EDT WED JUL 17 2013
SFC OBS SHOW THAT AFTERNOON INLAND TEMPS HAVE REACHED THE CONVECTIVE
TEMPERATURE AT MANY LOCATIONS (INTO THE UPPER 80S AND LOWER 90S) AND
THUS HAVE STARTED TO SEE ISOLD SHRA/TSRA BEGINNING TO FORM OVER FAR
WRN UPR MI AND ALONG THE LAKE SUPERIOR LAKE BREEZE AND VNCTY OF
STALLED OUT FRONT IN NORTH CENTRAL UPR MI. WITH SBCAPE VALUES OF
2000-2500 J/KG AND ALONG WITH EFFECTIVE BULK SHEAR VALUES 35-40 KT
THERE IS A CHANCE THAT SOME OF THESE STORMS COULD BECOME SVR THIS
AFTERNOON INTO THIS EVENING. AS A RESULT SPC HAS MUCH OF UPR MI IN A
SLIGHT RISK FOR DAY1 CONVECTIVE OUTLOOK AND HAS JUST ISSUED A SWOMCD
FOR POSSIBLE SVR TSTM WATCH ISSUANCE. UNIDIRECTIONAL FLOW PARALLEL
TO THE SURFACE BOUNDARIES COULD SUPPORT STORM DEVELOPMENT FAVORING
FORWARD PROPAGATING LINE SEGMENTS AND SMALL BOW ECHOES WITH THE
POTENTIAL FOR DAMAGING WINDS AND HAIL ALONG WITH HEAVY RAIN.
EXPECT MUCH OF THE CONVECTION FORMING NOW TO GRADUALLY DIMINISH BY
LATE THIS EVENING AS HEATING/INSTABILITY WANES A BIT. STORMS SHOULD
THEN REDEVELOP LATER TONIGHT TO THE WEST OVER NRN MN AS WARM
ADVECTION KICKS IN ALONG STALLED OUT FRONTAL BOUNDARY IN RESPONSE TO
SHORTWAVE ROUNDING BROAD 5H RIDGE. LOOK FOR STORMS TO THEN TRACK ESE
ALONG FRONTAL BOUNDARY AND 850-300 MB THCKNS LINES AND INTO UPPER MI
ON THURSDAY...ESPECIALLY AFFECTING THE NRN AND ERN PORTIONS OF THE
CWA. WITH PWATS EXCEEDING 2.00 INCHES OR 190-195 PCT OF NORMAL...
TORRENTIAL HEAVY RAIN WILL BE POSSIBLE WITH STORMS AND THERE IS A
POTENTIAL FOR SOME FLASH FLOODING IF STORMS CONTINUE TO TRACK OVER
THE NRN AND ERN PORTIONS OF THE CWA DURING THE DAY ON THURSDAY. WITH
MLCAPES VALUES FORECAST TO BE NEAR 1500 J/KG AND DEEP LAYER SHEAR
VALUES OF 35-45 KT THERE IS AGAIN A POTENTIAL FOR SVR STORMS ON THU
AND SPC HAS ALL OF UPR MI HIGHLIGHTED IN SLIGHT RISK. COMBINATION OF
VEERING WIND PROFILE IN THE LOWER LVLS...STRONG
INSTABILITY...MODERATE TO STRONG DEEP LAYER...AND VERY MOIST
DEWPOINTS IN THE LOWER 70S CONTRIBUTING TO LOW LFC HEIGHTS COULD ALL
SUPPORT SUPERCELL DEVELOPMENT. ALTHOUGH THE PRIMARY THREATS WITH
THURSDAYS STORMS WILL LIKELY BE DAMAGING WIND...HEAVY RAIN AND LARGE
HAIL...ISOLD TORNADOES WILL ALSO BE POSSIBLE ESPECIALLY WITH ANY
STORMS THAT INTENSIFY AND MOVE EWD ALONG WARM/QUASISTATIONARY
FRONTAL BOUNDARY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 432 PM EDT WED JUL 17 2013
THURSDAY NIGHT THROUGH FRIDAY...A SLOW MOVING WARM FRONT WILL
CONTINUE TO LIFT FROM LAKE SUPERIOR NORTHWARD INTO ONTARIO DURING
THE EVENING HOURS AS A COLD FRONT IS PUSHED SOUTHEASTWARD OUT OF
SOUTHERN MANITOBA INTO NORTHEASTERN MN DURING THE OVERNIGHT HOURS. AT
THE SAME TIME THE UPPER LEVEL 500MB TROUGH WILL BEGIN DIGGING
SOUTHWARD INTO THE REGION. OUT AHEAD OF THE COLD FRONT A 40KT LLJ IS
EXPECTED TO DEVELOP AND REMAIN IN PLACE THROUGH THE OVERNIGHT HOURS.
THIS WILL CONTINUE TO PUMP MOISTURE INTO THE AREA. WHILE THE FORECAST
SOUNDINGS GAIN A BIT MORE MOISTURE THROUGHOUT...DRY AIR REMAINS IN
PORTIONS OF THE MID AND LOWER LEVELS...IF THIS IS NOT ALTERED BY
EARLIER CONVECTION...THEREFORE A CONTINUED WIND THREAT WILL EXIST
DURING THE EVENING AND OVERNIGHT HOURS. STRONG TO SEVERE
THUNDERSTORMS WILL BE POSSIBLE THURSDAY EVENING INTO THE OVERNIGHT
HOURS AS 0-6KM SHEAR VALUES ARE EXPECTED TO BE AROUND 40 TO 45 KNOTS
ALONG AND AHEAD OF THE COLD FRONT...WITH SHEAR VECTORS BECOMING
PERPENDICULAR TO THE FORCING. PWATS DURING THIS TIME PERIOD WILL BE
150-200 PERCENT OF NORMAL LEADING TO VERY HEAVY RAIN POTENTIAL. LATE
THURSDAY NIGHT THROUGH FRIDAY AFTERNOON THE COLD FRONT TO THE
NORTHWEST OF THE AREA WILL CONTINUE SOUTHEASTWARD PUSHING SOUTHEAST
OF THE AREA BY LATE FRIDAY AFTERNOON. FORCING ALONG AND AHEAD OF THE
COLD FRONT...ALONG WITH CONTINUED MOISTURE FLOWING INTO THE
SYSTEM...WILL KEEP AN INCREASED CHANCE FOR SHOWERS AND THUNDERSTORMS
IN THE FORECAST THROUGH FRIDAY MORNING. THE SEVERE THREAT WILL SHIFT
SOUTHEASTWARD INTO THE LOWER GREAT LAKES BY FRIDAY AFTERNOON AS THE
FRONT SHIFTS OUT OF THE AREA. THE UPPER LEVEL 500MB TROUGH WILL MOVE
DIRECTLY OVERHEAD BY FRIDAY AFTERNOON...WHICH WILL KEEP A CONTINUED
SLIGHT CHANCE OF SHOWERS AND POSSIBLY AN ISOLATED THUNDERSTORM IN THE
FORECAST...HOWEVER THE COVERAGE WILL BE GREATLY REDUCED.
FRIDAY NIGHT THROUGH SUNDAY NIGHT...FRIDAY NIGHT THE UPPER LEVEL
500MB TROUGH AXIS WILL SHIFT TO THE EAST OF THE UPPER GREAT LAKES AS
HIGH PRESSURE OVER SOUTHERN CANADA AND THE NORTHERN PLAINS BEGINS TO
BUILD INTO THE REGION. NORTHERLY FLOW ON THE EAST SIDE OF THE HIGH
WILL PUSH COOLER AND DRIER AIR IN FROM CANADA AS SHOWN BY OVERLAYING
1000-500MB RH...MSLP AND MOISTURE TRANSPORT. THE HIGH PRESSURE
SYSTEM WILL CONTINUE TO SHIFT EASTWARD BECOMING DIRECTLY OVERHEAD
SATURDAY NIGHT INTO THE DAY SUNDAY. WITH THE HIGH DIRECTLY
OVERHEAD...WINDS WILL BE LIGHT AND VARIABLE ALLOWING TEMPERATURES TO
POSSIBLY COOL INTO THE LOW AND MID 40S...ESPECIALLY OVER THE INLAND
WEST AREA. THE HIGH PRESSURE SYSTEM IS PROGGED TO REMAIN OVER THE
CWA INTO SUNDAY NIGHT.
MONDAY THROUGH WEDNESDAY...CONSIDERABLE DIFFERENCES REMAIN IN TIMING
AND STRENGTH OF UPPER LEVEL WAVES MOVING INTO THE AREA ALONG WITH
MOISTURE AND SURFACE PRESSURE FIELDS. THIS DIFFERENCE OCCURS FROM
MODEL TO MODEL AND FROM MODEL RUN TO MODEL RUN FOR THE WEATHER
PATTERN OVER THE FIRST HALF OF NEXT WEEK. WITH SUCH INCONSISTENCIES
HAVE DECIDED TO STICK WITH A CONSENSUS OF THE MODELS FOR THIS TIME
PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 146 AM EDT THU JUL 18 2013
THE MAIN FOCUS OF CONCERN FOR THIS FORECAST PERIOD WILL BE
THUNDERSTORM DEVELOPMENT ALONG/NEAR THE COLD FRONT ACROSS UPPER
MICHIGAN. EXPECT SHOWER AND THUNDERSTORM DEVELOPMENT TO BECOME A
LITTLE MORE ACTIVE OVERNIGHT ALONG THE FRONT...WITH THE BEST CHANCES
FOR SHOWERS/STORMS BEING IN IWD AND CMX. TOUGH TO PIN POINT ANY
EXACT TIMING FOR THE STORMS...BUT THE EXPECTATION IS THAT ANY STORM
WILL CREATE TORRENTIAL DOWNPOURS AND BRIEF IFR CONDTIONS. SHOULD BE
A LITTLE LULL IN PCPN TMRW MORNING INTO EARLY AFTERNOON BEFORE THE
NEXT ROUND DEVELOPS LATE THU AFTN INTO EVENING. THESE COULD END UP
BEING STRONG TO SEVERE ESPECAILLY IF THEY DEVELOP INTO A ORGANIZED
CONVECTIVE COMPLEX.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 432 PM EDT WED JUL 17 2013
WITH RELATIVELY WEAK PRES GRADIENT AND HI STABILITY OVER THE
RELATIVELY COOL LAKE WATERS...EXPECT WINDS NO HIGHER THAN 20 KTS
THIS FORECAST PERIOD. THE MAIN WEATHER CONCERN WILL BE FOG WITH A
HUMID AIRMASS DOMINATING. THIS FOG IS LIKELY TO BE MOST WIDESPREAD
ON THU NIGHT FOLLOWING SOME STRONG TO POSSIBLY SVR THUNDERSTORMS
THAT WILL FURTHER SATURATE THE MARINE LAYER. THE ARRIVAL OF DRIER
AIR ON FRI SHOULD DISSIPATE THE FOG.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...MRD
SHORT TERM...VOSS
LONG TERM...KEC
AVIATION...MRD
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS GAYLORD MI
116 AM EDT THU JUL 18 2013
.SYNOPSIS...
ISSUED AT 429 PM EDT WED JUL 17 2013
A LARGE AREA OF HIGH PRESSURE WILL CONTINUE TO BRING HOT WEATHER TO
NORTHERN MICHIGAN THROUGH THURSDAY...WITH MUGGY CONDITIONS LINGERING
THROUGH THE WORK WEEK. CHANCES FOR SHOWERS AND THUNDERSTORMS WILL
GRADUALLY INCREASE STARTING TONIGHT...AS A COLD FRONT APPROACHES THE
UPPER GREAT LAKES AND MOVES THROUGH THE REGION. A COOLER AND MORE
COMFORTABLE AIR MASS WILL SETTLE INTO MICHIGAN THIS WEEKEND.
&&
.UPDATE...
ISSUED AT 111 AM EDT THU JUL 18 2013
UPDATES THE FORECAST FOR ADDING POPS/INCREASING POPS AROUND THE
THETA-E GRADIENT NEAR THE FRONT THAT DROPPED SOUTH INTO EASTERN
UPPER. WEAKISH LLJ DOES PROVIDE CONVERGENCE OVER FAR NRN LAKE
MICHIGAN...AND THIS LLJ COULD GET A BOOST FROM THE MORE STABLE
DOME OF AIR OVER THE COOLER WATERS. LATEST HRRR SUPPORTS THIS
NOTION. ROUGHLY 08Z-14Z FOR THE PEAK TIMES FOR CONVECTION.
UPDATE ISSUED AT 1029 PM EDT WED JUL 17 2013
SPOTTY CONVECTION UPSTREAM HAS BEEN STRUGGLING TO CROSS FAR NORTHERN
LAKE MI...AND AT THE MOMENT VERY LITTLE PRECIP IS OCCURRING IN
THIS FORECAST AREA. HOWEVER...SPOTTY CONVECTION CONTINUES TO BE
GENERATED UPSTREAM...THOUGH WITH NO SIGNS OF UPSCALE GROWTH TO A
FORWARD-PROPAGATING MCS. A FEW SHRA/TSRA ARE ALSO FIRING JUST OFF
OF ARENAC/IOSCO COUNTIES.
GIVEN RADAR TRENDS IN OUR IMMEDIATE VICINITY...IT IS QUITE
TEMPTING TO START YANKING POPS OUT OF THE FORECAST LEFT AND RIGHT.
HAVE TENDED TO DIMINISH PRECIP...BUT HAVE CHOSEN NOT TO GO
OUTRIGHT DRY. WE HAVE A 25KT WESTERLY 850MB JET...HELPING TO
SUPPORT AN INCREASE IN CONVECTION IN WESTERN UPPER MI. THIS JET
DOES NOT MAKE A TON OF EASTWARD PROGRESS TONIGHT....WITH THE TIP
PUSHING EAST TOWARD MUNISING/ESC. BUT THE ELEVATED CONVECTION IT
SPAWNS SHOULD HAVE EASIER TIME CROSSING THE COOLER LAKE WATERS. SO
HAVE KEPT CHANCY POPS IN FOR A GOOD CHUNK OF NORTHERN
MI...SOUTHERN SECTIONS EXCLUDED.
IN THE MEANTIME...SKIES ARE NOT QUITE AS CLOUDY AS EARLIER
EXPECTED. BETWEEN THAT AND PRECIP...AND TEMPS ARE ALREADY A LITTLE
THAN PROGGED IN SOME (MAINLY NORTHERN) AREAS. WILL BE LOWERING MIN
TEMPS A SMIDGE WHERE APPROPRIATE.
UPDATE ISSUED AT 742 PM EDT WED JUL 17 2013
JUST KEEPING UP WITH PRECIP TRENDS AT THIS POINT...WITH HIGHER
POPS IN THE STRAITS AND OTHER SOUTHERLY SECTIONS OF EASTERN
UPPER...AND LOWER ELSEWHERE. EARLIER ACTIVITY IN WI HAD ABSOLUTELY
NO SUCCESS IN CROSSING COOL LAKE MI. WILL WAIT AND SEE IF ACTIVITY
WELL UPSTREAM IN THE MN ARROWHEAD CAN PRODUCE ENOUGH OF A COLD
POOL TO MAKE A RUN EASTWARD. BUT WITH WESTERLY 850MB AND 950MB
FLOW THRU THE NIGHT...THE SET-UP IS FAR FROM CLASSICAL FOR A
NOCTURNAL MCS TO TAKE A RUN AT US.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 429 PM EDT WED JUL 17 2013
VERY WARM AND HUMID CONDITIONS PERSIST COURTESY OF 599 DM 500 MB
HIGH SITTING ACROSS THE LOWER GREAT LAKES...WITH HEAT INDICES
RUNNING 90 TO 100 DEGREES. AS TALKED ABOUT IN MORNING DISCUSSION...
SFC DEWPOINTS HAVE MIXED OUT/DROPPED OVER PARTS OF NRN LOWER
MICHIGAN THIS AFTERNOON...MAINLY NORTH OF M-32...RESULTING IN A
WEDGE OF REDUCED INSTABILITY ACROSS THE TIP OF THE MITT INTO
EASTERN UPPER MICHIGAN. A BIT MORE INSTABILITY SOUTH OF M-72 WITH
MLCAPE VALUES IN EXCESS OF 2500 J/KG. ANOTHER AXIS OF INSTABILITY
STRETCHES UP THROUGH EASTERN WISCONSIN INTO CENTRAL UPPER
MICHIGAN.
A FEW SMALL AREAS OF STORMS HAVE ONCE AGAIN DEVELOPED NORTH AND
WEST OF THIS CWA...ONE LINE ACROSS CENTRAL AND INTO EASTERN UPPER
MICHIGAN ALONG LAKE SUPERIOR MARINE BOUNDARY. SECOND SMALL BATCH
OF STORMS IN EASTERN WISCONSIN.
TONIGHT...KEEPING AN EYE ON STORMS TO THE NORTH AS SOME STRONGER
MID LEVEL FLOW (AND INCREASED DEEP LAYER SHEAR) IS SAGGING INTO
NRN MICHIGAN...WHICH WILL AID STORM ORGANIZATION. BUT IN THE
MEANTIME...INSTABILITY DOES DWINDLE HEADING EAST AND SOUTH INTO
CHIP/MACK COUNTIES AS WELL AS THE TIP OF THE MITT...SUGGESTING ONGOING
STORMS WILL DIMINISH AS THEY TRY TO SAG INTO THIS CWA (SIMILAR TO
YESTERDAY). WILL SEE...BUT THERE IS CERTAINLY A THREAT FOR A FEW
STRONGER STORMS PRODUCING GUSTY WINDS/SMALL HAIL AND HEAVY RAIN
HEADING INTO THE EVENING FOR EASTERN UPPER MICHIGAN...WITH SOME OF
THAT REMNANT ACTIVITY ULTIMATELY SAGGING DOWN INTO NRN LOWER
MICHIGAN THIS EVENING.
MEANWHILE...THINK STORMS OVER EASTERN WISCONSIN WILL FIZZLE AS
THEY TRY TO WORK ACROSS COOLER LAKE MICHIGAN. BUT STILL THE
POSSIBILITY FOR POP-UP SHOWERS/STORMS OVER THE EASTERN/SRN COUNTIES
HEADING INTO THE EVENING...BUT WITH A LOWER RISK FOR STRONG
STORMS (MORE OF A PULSE TYPE THREAT).
THURSDAY...AFOREMENTIONED FRONT IS EXPECTED TO SAG INTO THE TIP OF
THE MITT REGION AND STALL OVERNIGHT THROUGH THE DAY THURSDAY. WITH
DAYTIME HEATING...THIS SHOULD SERVE AS THE FOCUS FOR ADDITIONAL
SHOWER AND THUNDERSTORM CHANCES ACROSS MUCH OF THE CWA ON THURSDAY
ALONG WITH AN INCREASED RISK FOR STRONGER STORMS AS STRONGER MID
LEVEL FLOW FURTHER INCREASES ACROSS NORTHERN MICHIGAN.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 429 PM EDT WED JUL 17 2013
BIG...AND PERHAPS WELCOMED...CHANGES ON THE WAY AS NOAM LONG-WAVE
PATTERN GOES THROUGH SOME SIGNIFICANT REALIGNMENT...WITH CURRENT
OVERHEAD HEAT DOME YIELDING TO EXTENDED NORTHEAST NOAM/GREAT LAKES
TROUGHING THROUGH THIS WEEKEND. ABOVE WILL SEND A RATHER VIGOROUS
(FOR MID SUMMER ANYWAY) COLD FRONT RAPIDLY SOUTHEAST ACROSS THE
NORTHERN LAKES FRIDAY...USHERING IN A MUCH MORE TOLERABLE AIRMASS
FOR THE WEEKEND. SUCH AN ABRUPT CHANGE LIKELY NOT TO BE A QUIET
ONE...WITH SHOWERS AND STORMS...POSSIBLY SEVERE...THURSDAY NIGHT AND
FRIDAY. MID RANGE GUIDANCE PROGS HAVE FULL SUPPORT FROM EARLY SUMMER
TRENDS...WITH TROUGHING AND NEAR SEASONAL TEMPERATURES DOMINATING
INTO MUCH OF NEXT WEEK. FIRST AND FOREMOST...THURSDAY NIGHT AND
FRIDAY`S STORM CHANCES WILL NEED ADDRESSING...WITH LATTER CONCERNS
CENTERED MORE ON TEMPERATURE TRENDS AND ADDITIONAL SHOWER CHANCES
HEADING INTO NEXT WORK WEEK.
PATTERN RECOGNITION ACTUALLY DECREASING THE CONFIDENCE LEVEL ON
THURSDAY NIGHT AND FRIDAY`S SHOWER AND STORM COVERAGE...LET ALONE
SEVERE POTENTIAL. FROM A CONCEPTUAL MODEL...CONDITIONS LOOK
PRETTY RIPE FOR RATHER WIDESPREAD SHOWERS AND STORMS FOR BOTH
PERIODS...WITH MID AND UPPER JET`S SPREADING SOUTH...HELPING ENTICE
FURTHER LIFT ON AN ALREADY RATHER BUOYANT AND MOIST AIRMASS.
GENERATION OF A RATHER VIGOROUS NORTHERN PLAINS COLD FRONT LATER
THURSDAY...AND ITS EVENTUAL PASSAGE ACROSS OUR AREA FRIDAY
AFTERNOON...ONE WOULD THINK WOULD ONLY HELP THE CAUSE. QUESTION NOT
OF ONE IF THUNDERSTORMS WILL FORM...BUT RATHER WHERE THEY FORM AND
THEIR EVENTUAL PATH. LATE THURSDAY HAS MCS DEVELOPMENT WRITTEN ALL
OVER IT....WITH WEAK AND NORTHWARD RETREATING WARM FRONT
INCREASINGLY BISECTED BY DEVELOPING 40+ KNOT LOW LEVEL JET...ALL THE
WHILE POCKET OF 2K-3K J/KG ML CAPE EXPANDS JUST SOUTH OF THIS FRONT
BY LATER THURSDAY AFTERNOON. RECENT GUIDANCE TRENDS SUGGEST MAX
COLLOCATION OF THE ABOVE EXPECTED ACROSS NORTHERN MINNESOTA/FAR
SOUTHERN ONTARIO/AND INTO WESTERN LAKE SUPERIOR WHERE AFTERNOON
STORMS WILL LIKELY QUICKLY CONGEAL INTO AN MCS THURSDAY EVENING.
WHAT HAPPENS THEREAFTER IS WHEN CONFIDENCE REALLY BEGINS TO WAVER.
FOLLOWING BEST MASS CONVERGENCE ON NOSE OF SLOWLY VEERING LOW LEVEL
JET SUPPORTS THIS WELL ORGANIZED...AND POTENTIALLY DAMAGING WIND
PRODUCING...MCS TRACKING ACROSS LAKE SUPERIOR AND SOUTHERN ONTARIO.
THIS...HOWEVER ...IS DEFINITELY NOT WRITTEN IN STONE JUST YET...WITH
A PROPENSITY FOR THESE SYSTEMS TO PIVOT TOWARDS BETTER INSTABILITY....
WHICH BY OVERNIGHT THURSDAY...STRETCHES RIGHT ACROSS NORTHERN
MICHIGAN. REALLY LIKE INHERITED FORECAST THAT KINDA SPLITS THE
DIFFERENCE BETWEEN THESE TWO IDEAS...WITH HIGHEST LIKELIHOOD OF ANY
IMPACTS ACROSS THE FAR NORTH. THIS PERIOD WILL CONTINUE TO BE
MONITORED CLOSELY AS COUPLING OF DEEP UNIDIRECTIONAL SHEAR (0-6KM
SHEAR MAGNITUDE IN EXCESS OF 45 KNOTS ACROSS THE NORTH) AND RATHER
UNSTABLE OVERNIGHT AIRMASS COULD POSSIBLE LEAD TO A RATHER
SUBSTANTIAL DAMAGING WIND EVENT. PER THE USUAL...FRIDAY`S SEVERE
WEATHER CHANCES TREMENDOUSLY DICTATED BY WHAT HAPPENS THURSDAY
NIGHT. CONCEPTUAL MODEL DEFINITELY SUPPORTS MORE SEVERE STORM
POTENTIAL WITH DEEP LAYER CONVERGENCE TIED TO STRONG COLD FRONT AS
IT PLOWS SOUTHEAST ACROSS OUR AREA. FOR ONCE...FRONTAL TIMING LOOKS
NICELY COUPLED WITH FAVORED DIURNALLY DRIVEN INSTABILITY CYCLE...
WITH MULTI-GUIDANCE PROGS SUGGESTING MAX CONVERGENCE SLIPPING ACROSS
NORTHERN MICHIGAN DURING THE AFTERNOON HOURS. DECENT POCKET OF MID
AND UPPER LEVEL SUPPORT COLLOCATED WITH THIS LOW LEVEL CONVERGENCE
AXIS...WITH RER UPPER JET DYNAMICS...40 TO 50 KNOTS OF MID LEVEL
FLOW...AND SOME UPWARD QG SUPPORT ALONG SHORTWAVE TROUGH. COMBINE
ALL THE ABOVE WITH AMPLE PRE-FRONTAL MOISTURE (PWAT VALUES WELL OVER
1.5 INCHES) AND CONDITIONS APPEAR VERY FAVORABLE FOR ADDITIONAL
THUNDERSTORM ACTIVITY...WITH SEVERE WEATHER A DISTINCT POSSIBILITY.
PLENTY OF RED FLAGS TO CONSIDER...HOWEVER...ALL TIED TO LINGERING
EFFECTS OF THURSDAY NIGHT ACTIVITY. DOES POST MCS AIRMASS HAVE AN
ADEQUATE TIME TO DESTABILIZE? WILL MCS INDUCED SUBSIDENCE OVERCOME
INCREASINGLY FAVORABLE SYNOPTIC SUPPORT? EVEN SOME OF THE NORTHERN
MCS SOLUTIONS FOR THURSDAY NIGHT SUGGEST OUR AREA BECOMING CAPPED AS
PRE-FRONTAL WAA STRENGTHENS FRIDAY...WITH STORMS FIRING VERY LATE
AND JUST TO OUR SOUTH. PLENTY TO PONDER IN THE COMING DAYS...AND
WILL SIMPLY KEEP A RATHER GENERIC FORECAST FOR NOW...WHILE MAINTAINING
HEIGHTENED AWARENESS OF SEVERE WEATHER POTENTIAL THROUGH OUR
HAZARDOUS WEATHER OUTLOOK AND BRIEFING.
GREAT AGREEMENT COLD FRONT WILL EXIT QUICKLY FRIDAY EVENING...
ENDING THE SHOWER AND STORM THREAT. POST-FRONTAL AIRMASS LOOKS
REFRESHING...WITH RATHER VIGOROUS CAA DROPPING HIGH TEMPERATURES
INTO THE UPPER 60S AND 70S FOR THE WEEKEND. DESPITE OVERHEAD MID
LEVEL TROUGHING...SURFACE HIGH PRESSURE AND A RATHER DRY AIRMASS
SHOULD PREVENT ANY AFTERNOON SHOWER DEVELOPMENT. PLENTY OF
UNCERTAINTY HEADING INTO NEXT WORK WEEK...CENTERED ON HARD TO TIME
WAVE (WAVES?). PERIOD WILL FEATURE SOME "CHANCY" WORDING...ALTHOUGH
LIKELY WILL BE OVERDONE COMPARED TO REALITY. PLENTY OF TIME TO
REVISIT THIS...WITH MUCH PRIORITY SET ON EARLIER PERIOD
WEATHER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 115 AM EDT THU JUL 18 2013
SOME FOG AT MBL LATE TONIGHT. TSRA CHANCES INCREASING THURSDAY
EVENING...ESPECIALLY AT PLN. LLWS LATE THU EVENING TVC/MBL.
CONTINUED HOT/HUMID.
SHRA/TSRA GENERATED IN UPPER MI CONTINUE TO WEAKEN AS THEY MOVE
ESE-WARD. AM EXPECTING WEAKISH LLJ IN WESTERLY FLOW...POKING INTO
FAR NRN LAKE MICHIGAN TO IGNITE NEW SHOWERS/STORMS AND RIDE INTO
PLN AND POSSIBLY APN SHORTLY AFTER DAYBREAK. FOR NOW...GIVEN LOW
CONFIDENCE...WILL HAVE VCSH. DO HAVE SOME MVFR FOG FOR A FEW
HOURS AT MBL. SOME CU AGAIN ON THURSDAY... BUT BEST CHANCE FOR
RAIN WILL WAIT FOR THE NIGHTTIME HOURS.
EXPECT AN ORGANIZED AREA OF STRONG TSRA TO DEVELOP TO OUR NW LATE
THURSDAY AFTERNOON. WHERE IT GOES IS UNCERTAIN...BUT THE MOST
LIKELY COURSE IS EASTWARD ACROSS SUPERIOR AND UPPER MI. THUS HAVE
LATE EVENING TSRA ONLY AT PLN FOR NOW.
LIGHT WINDS TONIGHT...A SW BREEZE THURSDAY. MBL/TVC WILL DECOUPLE
JUST ENOUGH THU EVENING TO ALLOW LLWS TO DEVELOP...WHEREAS PLN
WILL JUST STAY GUSTY.
&&
.MARINE...
ISSUED AT 429 PM EDT WED JUL 17 2013
RELATIVELY LIGHTER WINDS WILL PREVAIL ON THE LAKES TONIGHT INTO
THURSDAY WITH NO MARINE HEADLINES ANTICIPATED. STRONGER WEST TO
SOUTHWEST WINDS DEVELOP THURSDAY NIGHT INTO FRIDAY AHEAD OF A
STRONG COLD FRONT THAT WILL PRESS THROUGH THE REGION ON FRIDAY.
SMALL CRAFT ADVISORIES MAY BE NEEDED FOR SOME NEARSHORE AREAS
DURING THAT TIME.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...HEAT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR MIZ016>036-041-042.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...SD
SYNOPSIS...TL
SHORT TERM...BA
LONG TERM...MB
AVIATION...JZ
MARINE...BA
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
1118 PM CDT WED JUL 17 2013
.UPDATE...LOOKING INCREASINGLY LIKELY THAT AT LEAST ISOLATED SHOWERS
AND STORMS WILL START TO MIGRATE WEST INTO THE REGION FROM ALABAMA
BEFORE DAYBREAK. NO SUGGESTION YET THAT ANY VERY ORGANIZED ACTIVITY
WILL COME INTO THE AREA BEFORE THIS TIME. FORECAST UPDATED AGAIN TO
INCREASE POPS A LITTLE MORE OVER THE PREVIOUS UPDATE. /BB/
&&
.PREV DISCUSSION... /ISSUED 855 PM CDT WED JUL 17 2013/
..STRONG TO SEVERE STORMS POSSIBLE TOMORROW AFTN/ERLY EVE...
UPDATE...SMALL DISTURBANCE PRECEDING LARGER DISTURBANCE
UNDERCUTTING RIDGE TO OUR NORTH HAS BEEN RESPONSIBLE FOR KICKING OFF
SCATTERED (AND OCCASIONALLY POTENT) THUNDERSTORMS THIS AFTERNOON
UNTIL JUST RECENTLY OVER SOUTHERN PORTIONS OF THE FORECAST AREA.
THIS SMALL DISTURBANCE IS MOVING OFF TO THE WEST AND GETTING READY
TO CLEAR THE REGION...ALTHOUGH A STRAY SHOWER OR STORM CANNOT BE
RULED OUT OVER THE NEXT FEW HOURS IN SOUTHWESTERN ZONES.
LATER TONIGHT THE WESTERN FRINGES OF THE LARGER DISTURBANCE (TUTT
TYPE LOW) WILL BE MOVING IN FROM THE EAST. PREVIOUS DISCUSSION
TALKED OF HOW MODELS HAD BEEN DOWNPLAYING ANY REDEVELOPMENT OF
CONVECTION IN OUR REGION LATE TONIGHT IN ASSOCIATION WITH THE
APPROACHING LOW ALOFT. HOWEVER...LATEST HRRR RUNS SHOW AT LEAST SOME
ISOLATED CONVECTION IN EASTERN MS LATE TONIGHT...AND THIS SEEMS
FEASIBLE GIVEN MODEL INSTABILITY OUTPUT AND THE FACT THAT SHOWERS
AND STORMS ARE NOW INCREASING IN EASTERN ALABAMA (AND MIGRATING
SLOWLY THIS DIRECTION). THUS...FORECAST FOR LATE TONIGHT THROUGH THE
MORNING HOURS TOMORROW UPDATED TO INCLUDE MENTION OF ISOLATED
SHOWERS/STORMS GRADUALLY SPREADING WEST. GIVEN STABILIZING BOUNDARY
LAYER LATE TONIGHT ANY ELEVATED INSTABILITY DRIVING STORM
DEVELOPMENT (IF SUCH OCCURS) SHOULD IMPART MINIMAL POTENTIAL FOR
HAZARDOUS WEATHER...ALTHOUGH LOCALIZED HEAVY DOWNPOURS ARE CERTAINLY
POSSIBLE. /BB/
PREV DISCUSSION... /ISSUED 412 PM CDT WED JUL 17 2013/
DISCUSSION...SHOWERS AND A FEW THUNDERSTORMS ARE ONGOING ACROSS
SOUTH MS AND PORTIONS OF NE LA AS AFTERNOON CONVECTIVE TEMPERATURES
ARE BEING REACHED IN THE LOW TO MID 90S. SHOWER/STORM COVERAGE IS
NOT GREAT ACROSS THE REGION, AS EXPECTED, WITH SYNOPTIC SUBSIDENCE
PREVAILING AS A RESULT OF H5 RIDGE INFLUENCE CENTERED OVER THE OHIO
VALLEY. ANOTHER NOTABLE FEATURE IS A DEVELOPING TUTT LOW AND
ASSOCIATED S/WV VORTICITY IMPULSES TRAPPED IN THE EASTERLY MID-LVL
FLOW ON THE SOUTHERN PERIPHERY OF THE LARGE H5 RIDGE ACROSS THE WRN
GOM AND SOUTHERN ATLANTIC SEABOARD. THIS TUTT WILL AID IN THE STORMS
TOMORROW.
CURRENT SHOWER AND THUNDERSTORM ACTIVITY WILL SLOWLY DIMINISH
THROUGH THE EARLY EVENING HOURS AS THE ATMOSPHERE DESTABILIZES BUT AN
OUTSIDE STRONG STORM MAY BE POSSIBLE IF MERGERS OCCUR. THE POTENTIAL
FOR STRONG STORMS ACROSS FAR EAST MS TONIGHT HAS BEEN DECREASING WITH
ACTIVITY REMAINING CONFINED IN GA THIS AFTN AND STRUGGLING FARTHER
WEST IN AL WITH A DIMINISHING CU FIELD. LOCAL WRF AND HRRR SUPPORT
THIS THINKING AND HAVE ADJUSTED POPS/WX FOR THE OVRNGT PERIOD
ACCORDINGLY.
AS TUTT LOW INFLUENCE INCREASES TOMORROW, A NOTABLE LOW-LVL
CONVERGENT WIND FIELD LOOKS TO DEVELOP, CREATING AN INITIAL
CONVECTIVE TRIGGERING MECHANISM. A MORE THAN SUPPORTIVE THERMO
ENVIRONMENT LOOKS TO BE IN PLACE WITH >3000 J/KG SBCAPE, 27-28C
VERTICAL TOTALS AND STEEP LOW-LVL LAPSE RATES WITH TOMORROW LIKELY
THE WARMEST OF THE WEEK AS READINGS CLIMB INTO THE MID 90S. IT`S
TOUGH TO PINPOINT WHAT AREA WILL BE MORE FAVORED FOR SCATTERED TO
NUMEROUS STORM DEVELOPMENT AS IT WILL DEPEND ON H5 INVERTED TROUGH
AXIS LOCATION AND SPEED. NAM AND SUBSEQUENT HI-RES OUTPUT BASED ON
ITS INITIAL CONDITIONS ARE A BIT FASTER THAN GFS AND DEPICT BEST
COVERAGE IN CENTRAL AND WEST AREAS WITH GFS A TOUCH SLOWER WITH
POTENTIAL GREATER COVERAGE IN THE EAST. HAVE BLENDED THE TWO (WHICH
IS MUCH HIGHER THAN MAV POPS SUGGEST AND FOLLOWED MUCH CLOSER TO MET
GUIDANCE FOR THURS AFTN PERIOD. GIVEN HIGH LAPSE RATES AND ADEQUATE
INSTABILITY, STRAIGHT LINE WINDS OF 60 MPH, HAIL, AND HEAVY
DOWNPOURS WILL BE LIKELY INVOF STRONGEST STORMS. STORM MOTION WILL
BE SLOW AS ATM COLUMN HAS LITTLE FLOW, FURTHER AIDING IN LOCALIZED
POTENTIAL FOR FLASH FLOODING. ACTIVITY WILL SLOWLY DIMINISH THROUGH
THE MID TO LATE LATE EVE AS THE MID-UPPER LOW TRAVERSES WEST ACROSS
THE SABINE RIVER.
FOR FRIDAY...ANOTHER ROUND OF DECENT COVERAGE OF SHOWERS AND STORMS
AS CONTINUED FAVORABLE LIFT AND INSTABILITY REMAIN IN THE AREA WITH
THE TUTT LOW OVER ERN TX. SOME STORMS DURING FRI AFTN COULD AT LEAST
BE ON THE STRONG SIDE AND WILL HAVE TO MONITOR MESOSCALE EVOLUTION
THURSDAY TO SEE IF SEVERE STORMS COULD BE ATTAINED FRIDAY. HAVE
ADDED WORDING TO THE HWO/GRAPHICS FOR FRIDAY AFTN FOR THIS STRONG
STORM POTENTIAL.
FOR FORECAST ELEMENTS...MET POPS WERE USED AS A STARTING POINT FOR
TOMORROW IN LIEU OF LOW MAV POPS. POPS WERE ALSO BOOSTED FRIDAY WITH
WEAKNESS IN THE RIDGE AND TUTT LOW INFLUENCE. MAV LOW TEMPS WERE
BUMPED UP 1-3F DEGREES WITH HIGHS BUMPED DOWN 2F DEGREES BASED ON
RECENT TRENDS. /ALLEN/
&&
.AVIATION...
MAINLY VFR CONDITIONS ARE ANTICIPATED THROUGH TONIGHT
AND INTO THE MORNING HOURS. HOWEVER...THERE WILL BE THE POTENTIAL
FOR ISOLATED SHOWERS/STORMS LATE TONIGHT IN EASTERN MS AND IN ALL
AREAS TOMORROW MORNING. CHANCES FOR ANY OF THIS ACTIVITY HITTING TAF
SITES RATHER LOW...BUT IF IT OCCURS THEN BRIEF IFR CONDITIONS IN
THIS TIME PERIOD NOT IMPOSSIBLE. OTHERWISE...A MUCH GREATER COVERAGE
OF CONVECTION AREAWIDE TOMORROW AFTERNOON INTO TOMORROW EVENING
ALTHOUGH AWAY FROM STORMS IN THIS PERIOD MOST FLIGHT CATS SHOULD
STILL REMAIN VFR. /BB/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 72 93 72 93 / 15 39 21 39
MERIDIAN 69 93 72 93 / 21 30 21 38
VICKSBURG 69 93 72 93 / 12 46 22 38
HATTIESBURG 72 93 73 93 / 22 42 21 44
NATCHEZ 70 91 72 91 / 14 46 21 48
GREENVILLE 74 95 74 94 / 11 46 20 37
GREENWOOD 72 94 72 94 / 14 30 17 40
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
BB/ALLEN
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1149 PM MDT WED JUL 17 2013
.AVIATION...
06Z TAF CYCLE
AN UPPER LEVEL LOW PRESSURE SYSTEM WILL TRACK SLOWLY SWWD FROM SW
NM TONIGHT INTO NW MEXICO BY THURSDAY EVENING. THIS TRACK AND
PERSISTENT...MOIST...SE LOW LEVEL FLOW ON THE BACK SIDE OF THE LOW
SHOULD FAVOR THE S CENTRAL MTS AND SE PLAINS FOR PERIODS OF LIGHT
RAIN AND POSSIBLY A FEW THUNDERSTORMS TONIGHT...THEN THE
MOUNTAINS AND AREAS S OF HIGHWAY 60 ON THURSDAY. THE UPSLOPE FLOW
ON THE PLAINS IS EXPECTED TO PRODUCE WDSPR MVFR AND IFR CONDITIONS
IN LOW CLOUDS AND A LITTLE PATCHY FOG ACROSS THE E TONIGHT INTO
THURSDAY MORNING...WITH A RISK OF AIRPORTS ALONG THE E SLOPES OF
THE CENTRAL MT CHAIN...INCLUDING KLVS AND KROW...DROPPING BELOW
AIRPORT MINIMUMS. FLIGHT CATEGORY RESTRICTIONS MAY LINGER INTO THE
EARLY AFTN THURSDAY ALONG AND E OF THE S CENTRAL MTS. LOW CLOUDS
SHOULD BE PATCHIER THURSDAY NIGHT...WHEN THEY SHOULD FAVOR
LOCATIONS E OF THE S CENTRAL MTS.
44
&&
.PREV DISCUSSION...625 PM MDT WED JUL 17 2013...
DECIDED TO KEEP FFA IN EFFECT FOR ROOSEVELT COUNTY THROUGH TONIGHT
AS RADAR TRENDS SHOW SIGNIFICANT AREA OF LOCALLY HEAVY RAINFALL RE-
DEVELOPING OVER WEST TEXAS LAST COUPLE HOURS. THE 21Z HRRR AND 23Z
RUC SOLUTION ARE IN AGREEMENT ALL CONVECTIVE ACTIVITY WILL BECOME
A MORE WIDESPREAD AREA OF MODERATE TO PERHAPS LOCALLY HEAVY RAIN
OVERNIGHT ALONG AND NEAR THE HIGH TERRAIN OF SOUTH CENTRAL AND
SOUTHEAST NM. FARTHER NORTH AND WEST HAVE LOWERED POPS ACCORDINGLY
AS GUIDANCE AND LATEST SATELLITE TRENDS SHOW LOTS OF CLEARING. SOME
REDEVELOPMENT MAY OCCUR DURING THE PREDAWN HOURS AS IS OFTEN THE
CASE IN MOIST MONSOON FLOW HOWEVER COVERAGE WILL BE VERY LIMITED.
GUYER
.PREV DISCUSSION...257 PM MDT WED JUL 17 2013...
THE LATEST WATER VAPOR SATELLITE IMAGERY SHOWS THE UPPER LOW
PROGRESSING SOUTHWEST ACROSS THE RIO GRANDE NEAR T-OR-C...WITH DRY
AIR WRAPPING INTO THE WEST SIDE OF THE CIRCULATION AND A VERY
MOIST ATMOSPHERE ON THE EAST SIDE. AREA 12Z UPPER AIR SOUNDINGS
CONFIRMED THIS...WITH BOTH KAMA AND KMAF SHOWING PWATS AROUND 1.5
INCHES AND ONLY 0.92 HERE AT KABQ (STILL SLIGHTLY ABOVE NORMAL).
12Z MODEL TIME SERIES FOR KABQ SHOWS PWAT INCREASING TO BETWEEN
1.1 AND 1.3 INCHES OVERNIGHT AND STAYING THERE THROUGH THE
WEEKEND. THIS INCREASE IN MOISTURE COMBINED WITH INCREASING TEMPS
EACH DAY SHOULD BRING BETTER CHANCES FOR RAIN TO THE ABQ METRO
FROM FRIDAY INTO THE WEEKEND.
FURTHER SOUTH...A FLASH FLOOD WATCH REMAINS IN EFFECT FOR MUCH OF
SOUTHEAST AND SOUTH CENTRAL PORTIONS OF THE STATE. WE`RE EXTENDING
OUR FLASH FLOOD WATCH FOR LINCOLN AND CHAVES COUNTY THROUGH
THURSDAY MORNING...BUT DROPPING ROOSEVELT AS THE FOCUS SHIFTS TO
THE FAVORED UPSLOPE AREAS OF THE SOUTH CENTRAL MOUNTAINS...
INCLUDING THE LITTLE BEAR BURN SCAR AND SOUTHWEST CHAVES COUNTY.
THE THREAT ON THURSDAY MAY PERSIST OVER THE SOUTH CENTRAL
MOUNTAINS AND WILL DEFINITELY PICK-UP OVER CATRON COUNTY AND THE
WHITEWATER-BALDY BURN SCAR. HIGH POP...HIGH PWAT SCENARIO WITH
UPSLOPE TO BOOT...BUT NOT THE BEST SURFACE BASED INSTABILITY
GIVEN EXTENSIVE CLOUD COVER FORECAST THURSDAY. STORM MOTION WILL
DECREASE SIGNIFICANTLY ON THURSDAY ACROSS NORTHERN PORTIONS OF THE
FORECAST AREA AS THE LOW PULLS FURTHER AWAY...SO ANY STORMS THAT
FORM OVER THE NORTH WILL BE MOVING SLOWER. HOWEVER...THE WARM-UP
ON THURSDAY WILL NOT BE SIGNIFICANT ENOUGH TO PRODUCE DEEPER
CONVECTION. THIS ALL CHANGES BY FRIDAY AS THE UPPER LOW WILL BE
OVER NORTHERN MEXICO AND STORM MOTION WILL BE EVEN LIGHTER ACROSS
THE NORTHERN MOUNTAINS. MORE WARMING ON FRIDAY WILL INCREASE
SURFACE BASED INSTABILITY WHILE PWATS REMAIN ABOVE TO WELL ABOVE
NORMAL. THIS ADDS-UP TO A LOCALLY HEAVY RAINFALL THREAT FRIDAY...
WITH PARTICULAR CONCERN FOR NORTHERN BURN SCARS. LOOK FOR A REPEAT
ON SATURDAY...WITH STORM MOTION NEAR ZERO FOR THE NORTHERN
MOUNTAINS.
LOOK FOR A CONVECTIVE DOWNTREND EARLY NEXT WEEK AS THE UPPER HIGH
OVER NEVADA MOVES EAST OR SOUTHEAST TO OVER CO/NM BY WEDNESDAY.
THE CONVECTIVE DOWNTREND DUE TO DECREASING MOISTURE AND INCREASING
PRESSURE HEIGHTS UNDER THE INFLUENCE OF A 595DAM 500MB HIGH.
TEMPERATURES ARE FORECAST TO BE BACK ABOVE NORMAL AREA-WIDE BY
TUESDAY AND STAY THERE FOR AWHILE.
11
.FIRE WEATHER...
LATEST IR IMAGERY INDICATES THAT THE UPPER LOW IS POSITIONED NEAR
SOCORRO...AND WILL CONTINUE TO SLIDE TOWARDS FAR SOUTHWEST NEW
MEXICO THIS EVENING. SHOWERS WILL CONTINUE ACROSS SOUTHEAST PORTIONS
OF THE STATE THROUGH THE REST OF THE DAY...AND BECOME MORE
CONVECTIVE WITH DAYTIME HEATING. THE FOCUS FOR THE HEAVIEST RAINS
WILL BE OVER THE SACRAMENTO MOUNTAINS AND COULD IMPACT BURN SCARS IN
THAT AREA. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL
ALSO BE POSSIBLE PRIMARILY OVER THE NORTHERN AND SOUTHWEST
MOUNTAINS. EAST WINDS AT 20 TO 30 MPH WITH GUSTS TO 40 MPH WILL
RETURN LATE THIS EVENING FOR THE ABQ METRO DUE TO A STRENGTHENED
PRESSURE GRADIENT. LITTLE CHANGE IN OVERNIGHT RH RECOVERIES IS
EXPECTED AND ANOTHER ROUND OF LOW CLOUDS AND PATCHY FOG WILL BE
POSSIBLE ACROSS THE EASTERN PLAINS.
THE UPPER LOW WILL CONTINUE TO WEAKEN AS IT MOVES OVER NORTHWEST
MEXICO THURSDAY. THE MAIN MOISTURE PLUME WILL BE FOCUSED OVER THE
SOUTHWEST MOUNTAINS...THOUGH SHOWER AND THUNDERSTORM ACTIVITY WILL
REMAIN POSSIBLE ACROSS MUCH OF THE STATE WITH DIURNAL HEATING.
TEMPERATURES WILL REMAIN BELOW NORMAL FOR MOST OF THE STATE...THOUGH
A 5 TO 10 DEGREE WARM-UP FROM WEDNESDAYS HIGHS IS EXPECTED.
LITTLE CHANGE IN OVERALL PATTERN FRIDAY AND INTO THE WEEKEND AS THE
UPPER LOW CONTINUES ITS SLOW TREK WEST WITH HIGH PRESSURE TO THE
NORTH SLOWLY BUILDING BACK OVER THE STATE. DIURNAL CONVECTION EACH
DAY WILL BE FOCUSED OVER WESTERN AND CENTRAL NEW MEXICO AND FAVOR
THE HIGH TERRAIN. A SLIGHT DRYING TREND THROUGH THIS PERIOD IS
EXPECTED...THOUGH OVERNIGHT RH RECOVERIES WILL REMAIN GOOD ALL AREAS
EXCEPT VALLEY LOCATIONS WHERE RECOVERIES WILL BECOME FAIR.
TEMPERATURES WILL TREND UP...REACHING NEAR NORMAL VALUES FOR THE
NORTHERN AND CENTRAL NEW MEXICO BY MONDAY. POCKETS OF FAIR TO POOR
VENTILATION RATES WILL BE POSSIBLE EACH DAY...MAINLY ACROSS
NORTHWEST NEW MEXICO.
THE GFS AND ECMWF SHOW SOMEWHAT SIMILAR DEPICTIONS FOR EARLY NEXT
WEEK. HIGH PRESSURE WILL BUILD OVER THE GREAT BASIN AND STRETCH OVER
THE STATE...RESULTING SHOWER AND THUNDERSTORM ACTIVITY ALONG THE
NM/AZ BORDER. THE PROGRESSION OF THIS HIGH PRESSURE EAST THROUGH THE
WEEK IS DEPICTED DIFFERENTLY...BUT A DECREASE IN SHOWER AND
THUNDERSTORM COVERAGE WILL BE POSSIBLE.
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 6 AM MDT THURSDAY FOR THE FOLLOWING ZONES...
NMZ526-536-538>540.
&&
$$
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
533 AM EDT THU JUL 18 2013
.SYNOPSIS...
AN ACTIVE WEATHER PATTERN WILL CONTINUE ACROSS THE NORTH COUNTRY
WITH DAILY CHANCES FOR SCATTERED SHOWERS AND THUNDERSTORMS...
ALONG WITH HOT AND HUMID CONDITIONS THROUGH THE END OF THE WEEK.
SOME STORMS COULD BE STRONG TO SEVERE THROUGH THE PERIOD. A COLD
FRONT WILL MOVE THROUGH ON SATURDAY BRINGING MUCH DRIER AND
COOLER AIR FOR SUNDAY AND MONDAY.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
AS OF 533 AM EDT THURSDAY...QUIET START TO THE DAY AS HIGH
PRESSURE REMAINS OVER THE MISSISSIPPI AND MISSOURI
VALLEYS...KEEPING THE NORTH COUNTRY IN FAIRLY ZONAL W-NW FLOW
ALOFT. HOT AND HUMID CONDITIONS CONTINUE TODAY...WITH INSTABILITY
AND MOSTLY CLEAR TO PARTLY CLOUDY SKIES ALLOWING FOR LOTS OF
DIURNAL HEATING...COMBINED WITH MIXED LAYER CAPE VALUES OF
1500+J/KG...LI OF -5C TO -7C...0-6KM SHEAR OF 30-40KTS WILL
TRIGGER SHOWERS AND THUNDERSTORMS THIS AFTN...WITH NAM AND GFS
INDICATING A SLGT WAVE/WARM FRONT AT THE SFC WHICH COULD HELP
KEEP CONVECTION LINGER INTO THE OVERNIGHT. THETA E GRADIENT TO
OUR NORTH IN SW QUEBEC...ALONG WITH UPPER LEVEL JET DYNAMICS
BEING TO THE NORTH WILL HAVE CONVECTION RELY ON DIURNAL HEATING.
WITHOUT NOTABLE SYNOPTIC FORCING...EXPECT CONVECTION TO START IN
THE EARLY/MID AFTN...ESP OVER HIGHER TRRN...WITH GUSTY WINDS AND
HEAVY DOWNPOURS AS PWATS WILL BE 1.5-2 INCHES. LIKELY TO BE SOME
LINGERING SHOWERS AND TSTMS THROUGH MIDNIGHT...BUT OVERALL
COVERAGE WILL BEGIN TO WANE AFTER 00Z.
HOT MUGGY DAY ON TAP WITH MAX TEMPS REACHING THE L90S IN THE
VALLEYS AND 70S IN THE HIGH TRRN. DEWPTS EXPECTED TO BE IN THE
M60S TO M70S. HEAT INDEX VALUES WILL APPROACH 100F DURING THE
PEAK DAYTIME HEATING.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH SATURDAY/...
AS OF 533 AM EDT THURSDAY...LINGERING CONVECTION THIS EVENING
WITH BR/FG DEVELOPING OVERNIGHT...ESP AT LOCATIONS THAT RECEIVE
RAINFALL. TOWARDS EARLY MORNING HOURS ON FRIDAY...NAM AND GFS
SHOW WARM FRONT LIFTING NWD...BEGINNING THREAT FOR SHOWERS AND
TSTMS EARLY. LLJ AROUND 30-45KTS WILL ACCOMPANY THE
FRONT...PROVIDING PLENTY OF SHEAR TO HELP ORGANIZE CONVECTION.
CAPE VALUES WILL BE EVEN HIGHER WITH OVER 2500 J/KG PSBL. CLEARLY
DEFINE THETA E RIDGING SUPPORTS INDICATIONS OF LARGE INSTABILITY
OVER THE AREA. WARM HUMID CONDITIONS CONTINUE ON FRIDAY...BUT
FRONT WILL ALSO HAVE SUPPORT FROM VORTICITY WHICH WILL CONTINUE
TO MOVE OVER THE REGION INTO THE OVERNIGHT. THEREFORE EXPECT BEST
CHCS FOR CONVECTION TO OCCUR ON FRIDAY INTO FRIDAY NIGHT AS MID
LEVEL HT FALLS SEE A MORE DRAMATIC CHANGE FRIDAY NIGHT WHILE
UPPER LEVEL TROUGH GAINS MOMENTUM EWD...GRAZING THE CENTRAL GREAT
LAKES AND PUSHING THE LOW PRESSURE SYSTEM AND ASSOCIATED COLD
FRONT AT THE SFC FORWARD. GOING INTO SATURDAY...COLD FRONT WILL
BE FOCUS OF SHOWERS AND TSTMS...WITH CAPE OVER 1000 J/KG AND LI
AROUND -3C. UPPER LEVEL JET ACCOMPANYING THE FRONT WILL POSITION
THE RR QUAD OVER THE SLV FRIDAY NIGHT AND MOVE EWD THROUGHOUT THE
DAY SATURDAY. THE COLD FRONT DOESN/T LOOK TO EXIT ERN VT UNTIL
LATE SATURDAY INTO SATURDAY EVENING.
TEMPS WILL BE HOT WITH 925MB REACHING MID20S ON FRIDAY...
RESULTING IN SFC MAX TEMPS IN THE U80S-M90S...ESP IN SW DOWNSLOPE
AREAS LIKE PBG. HEAT INDEX VALUES WILL ONCE AGAIN APPROACH 100
DEGREES IN A FEW LOCATIONS MAINLY IN THE CPV AND CT VALLEY. WITH
MORE CLD COVER ON SATURDAY...EXPECT MAX TEMPS TO BE IN THE
M-U80S. OVERNIGHT MIN TEMPS WILL BE WARM...IN THE 60S- L70S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 407 AM EDT THURSDAY... IT WILL BE NOTICEABLY COOLER AND
DRIER SUNDAY AND MONDAY BEFORE RETURNING TO NEAR NORMAL TUESDAY
AND WEDNESDAY WITH A CHANCE OF SHOWERS AND THUNDERSTORMS.
A BROAD AREA OF CANADIAN HIGH PRESSURE SETTLES INTO THE REGION
SUNDAY INTO MONDAY. 850 TEMPS DROPS TO AROUND 6C BUT MODIFY BACK
TO 8-11C WITH DAYTIME HEATING SO MAX TEMPERATURES EXPECTED IN THE
70S ON SUNDAY AND NIGHTTIME LOWS IN THE 50S WITH KSLK PERHAPS MID
40S.
A BIT MORE UNCERTAIN BY TUE AND WED WITH TIMING OF SHORT WAVE
TROFS WHICH ARE EXPECTED TO CARVE OUT A MEAN LONGER WAVE AND
PERSISTENT TROF SOMEWHERE OVER FROM WESTERN GREAT LAKES INTO THE
NORTHEAST. WE WILL TEND TO BE ON THE ACTIVE SIDE OF THE TROF SO
HAVE BROUGHT A CHANCE OF SHOWERS AND SLIGHT CHANCE OF THUNDER
INTO THE AREA ON TUE-WED. ECMWF IS FASTER THAN GFS/GEFS SO HAVE
TWEAKED THE POPS UP INTO 30 PERCENT RANGE FOR NOW. TEMPERATURES
WILL CREEP UP TO AROUND NORMAL BUT IF IT`S SHOWERY DURING THE
DAY, IT COULD BE A BIT COOLER. LOWS MAINLY 55 TO 65 AND HIGHS 75
TO 82.
&&
.AVIATION /09Z THURSDAY THROUGH MONDAY/...
THROUGH 00Z FRIDAY...MAINLY VFR AT KBTV/KPBG. OTHER SITES WILL
HAVE SOME IFR IN BR AND VLIFR AT TIMES IN FOG THROUGH 12Z AT KSLK
AND KMPV. FOG WILL BURN OFF 12-14Z.
NOT EXPECTING TOO MUCH IN THE WAY OF SHOWERS OR THUNDER UNTIL
SCATTERED THUNDERSTORMS DEVELOP GENERALLY AFTER 17Z AND HAVE
INCLUDED VCTS. IF A THUNDERSTORM WERE TO MOVE OVER A TAF SITE I
WOULD EXPECT BRIEF IFR VSBYS AND MVFR CIGS BUT TOO UNCERTAIN TO
INCLUDE AT THIS TIME OF DAY.
CONVECTION EXPECTED TO GRADUALLY DIE OFF TOMORROW NIGHT WITH SOME
BR EXPECTED AFTER 03Z.
WINDS LGT/VAR..THEN W-SW 5-10KTS FROM 13Z-14Z THURSDAY ONWARD.
OUTLOOK 06Z FRIDAY THROUGH MONDAY... 06Z FRIDAY - SAT LCL IFR
FG/BR OVERNIGHT...MAINLY AT KSLK/KMPV. SCATTERED MAINLY AFTERNOON
SHOWERS/THUNDERSTORMS BUT CANT RULE IT OUT AT ANY TIME THROUGH
SAT WITH BRIEF MVFR/IFR VISIBILITIES.
SUNDAY AND MONDAY...VFR UNDER BUILDING HIGH PRESSURE.
&&
.CLIMATE...
MAX TEMP RECORDS TODAY THROUGH FRIDAY. BEST SHOT OF REACHING OR
BREAKING RECORD MAX TEMPS ON FRIDAY AT KMPV AND KMSS. SHORTER
PERIOD OF RECORD AT THESE SITES THAN AT K1V4 AND KBTV.
07/18/2013 07/19/2013
KBTV 99/1953 98/1942
KMPV 96/1953 92/1991
K1V4 99/1953 95/1991
KMSS 95/1953 93/1991
&&
.EQUIPMENT...
KTYX RADAR FUNCTIONING BUT WE MUST MAINTAIN VCP21 THROUGH AT LEAST THIS
MORNING OR UNTIL A SOLUTION IS FOUND BY THE TECHNICIANS FROM FORT
DRUM.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...KGM/TABER
NEAR TERM...KGM
SHORT TERM...KGM
LONG TERM...SISSON
AVIATION...SISSON
CLIMATE...WFO STAFF
EQUIPMENT...WFO STAFF
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1147 PM CDT WED JUL 17 2013
.UPDATE...
ISSUED AT 1142 PM CDT WED JUL 17 2013
NO CHANGE IN THINKING SINCE UPDATE ISSUED PRIOR. WILL HAVE SCT
TRW- IN NORTHERN AND NORTHEASTERN HALF OF FCST AREA TONIGHT...WITH
DRY JMS-FAR-FFM SOUTHWARD.
UPDATE ISSUED AT 959 PM CDT WED JUL 17 2013
AS EXPECTED MOST OF THE CONVECTION ALONG THE FRONTAL BOUNDARY HAS
WEAKENED SUBSTANTIALLY SINCE 01Z. WINDS INDICATE THE BOUNDARY HAS
SLIPPED SOUTH OF FARGO-MOORHEAD AT 03Z...WITH WINDS INDICATING
BOUNDARY FROM SOUTH OF BEMIDJI TO NORTH OF DETROIT LAKES THEN JUST
SOUTH OF FARGO THEN BACK SOUTH OF VALLEY CITY-JAMESTOWN TO LOW
WEST OF BISMARCK.
WEAK 850 MB WARM ADVECTION ONGOING CURRENTLY WILL LIKELY CONTINUE
ISOLD SHOWERS NEW FEW HOURS. QUESTION IS OVERNIGHT...RAP13
CONTINUE TO SHOW 25 KT LOW LEVEL JET AND PRETTY STRONG BUT NARROW
850 MB WARM ADVECTION ZONE NEAR HIGHWAY TWO REGION OVERNIGHT INTO
THU MORNING AND HRRR DOES BREAK OUT PRECIP NR 07Z BTWN MOT-BIS-JMS
AND MOVES IT EAST-NORTHEAST....SO WILL CERTAINLY MAINTAIN CHANCE
OF STORMS FOR THE OVERNIGHT NORTH OF THE BOUNDARY. THE SHOWERS
ALONG THE INTL BORDER HAVE WEAKENED CONSIDERABLY BUT STILL A FEW
AROUND.
UPDATE ISSUED AT 658 PM CDT WED JUL 17 2013
WARM FRONTAL BOUNDARY LOCATED JUST SOUTH OF BEMIDJI TO ADA THEN TO
NEAR JAMESTOWN. AS EXPECTED WITH DAYTIME HEATING A CU FIELD FORMED
ALONG THE BOUNDARY AND SOME SMALL TSTMS FORMED IN A SCATTERED
FASHION ALONG IT. STRONGEST CELL ATTM NORTHEAST OF BISMARCK. NOT
TOO MUCH TO KEEP THESE GOING PAST DARK SO THESE WILL DIE OFF. A
LARGER AREA OF MORE GENERAL LIGHT RAIN SPREADING THRU SE SASK INTO
SOUTHERN MANITOBA AND SKIRTING THE ND BORDER THIS EVE AND DID
INCREASE POPS TO HIGH CHC OR LIKELY RIGHT ALONG THE BORDER FOR
THIS RAIN. THIS RAIN ASSOC WITH 500 MB SHORT WAVE SHOWN ON WATER
VAPOR NR THE SK/MB/ND BORDER REGION.
BIGGEST QUESTION IS OVERNIGHT. RAP MODEL DOES HAVE A 25 KT 850 MB
JET AND WARM ADVECTION CENTERED FROM CNTRL ND INTO NORTH CENTRAL
MN IN THAT 08Z-12Z PERIOD AND WOULD EXPECT TO SEE AN INCREASE IN
STORM COVERAGE NEAR THIS REGION (OR NEAR HIGHWAY TWO) LATER
TONIGHT WITH MORE GENERAL SHOWERS FARTHER NORTH. SO DID MAINTAIN
AN INCREASE IN POPS OVERNIGHT NORTH AND EAST AREAS OF THE FCST AREA.
DID REMOVE OR DIMINISH POPS IN THE SOUTH TONIGHT AS DOUBT ANY
PRECIP SOUTH OF I-94 THRU 18Z THU AS THAT AREA IN THE WARM AND
CAPPED AIRMASS AND SOUTH OF ANY LOW LEVEL JET INTERACTIONS.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 256 PM CDT WED JUL 17 2013
CURRENT SATELLITE SHOWS CU BEGINNING TO DEVELOP ALONG STAGNANT
WARM FRONTAL BOUNDARY STRETCHED ACROSS MY SOUTH...ROUGHLY ALONG A
BJI TO JMS LINE. POOL OF 70+ DEW POINTS ARE JUST SOUTH OF THE
BOUNDARY WITH DEW POINTS IN THE MID 50S ACROSS THE NORTH. CAPES
AROUND 2500 J/KG ACROSS THE SOUTH LACK THE SHEAR FOR ANY
SIGNIFICANT ACTIVITY THIS EVENING...BUT WILL PUT IN ISOLATED
STORMS ALONG THE FRONTAL BOUNDARY INTO THE MID EVENING HOURS.
40+ KT SHEAR BOUNDARY RUNS ROUGHLY ALONG THE HWY 200 CORRIDOR AND
NORTH...SO AGAIN NO SIGNIFICANT SHEAR IN OUR MOST HEATED OUT
REGION. GENERALLY USING A NAM/WRF BLEND THROUGH 06Z THEN
TRANSITION TO A MODEL BLEND FOR MAIN EVENT ON THURSDAY.
FORECAST CHALLENGE WILL BE SEVERE POTENTIAL ON THURSDAY.
LATE AFTERNOON/EARLY EVENING...COULD SEE SOME ISOLATED STORMS
ALONG BOUNDARY IN THE SOUTH...HOWEVER THERE IS A LACK OF 0 TO 6 KM
SHEAR.
TONIGHT...WARM FRONTAL BOUNDARY WILL BEGIN TO DRIFT NORTH AS LOW
PRESSURE STRENGTHENS AND MOVES INTO THE WRN DAKOTAS. ISENTROPIC
LIFT/WARM ADVECTION WITH A VERY MOIST AIRMASS WILL HELP INITIATE
SHOWERS/TSTMS ACROSS THE NORTH...IN REGION OF STRONGER SHEAR
ALOFT. THEREFORE COULD SEE SOME STRONG STORMS AFT AROUND
09Z...WHEN MODELS MOST AGREE ON PLACEMENT/TIMING OF PRECIP.
THURSDAY...WARM FRONTAL BOUNDARY WILL LIFT NORTHWARD TO ALONG THE
HWY 200 CORRIDOR BY 12Z AND NORTH OF GFK BY 18Z. SOUTHERN HALF OF
THE CWA SHOULD HEAT UP MUCH LIKE TODAY...WITH CAPES NEARING 3K
J/KG BY MID AFTN. FRONTAL BOUNDARY WILL BE FURTHER NORTH AND
MODELS SHOWING SHEAR VALUES OF 50 KT ALONG INTL BORDER. SEVERE
THREAT CONTINUES ALONG THE NORTHERN THIRD OF THE CWA...WITH
SOUTHERN TWO THIRDS MORE QUESTIONABLE DUE TO CONVECTIVE
INHIBITION. ALTHOUGH FREEZING LEVELS WILL BE QUITE HIGH...LARGE
HAIL A GOOD POSSIBILITY. ALSO A THREAT FOR TORNADOES WITH SFC
BOUNDARY ACROSS NORTHERN ZONES. POTENTIAL EXISTS FOR HEAT
ADVISORY CRITERIA ACROSS SOUTHERN HALF OF CWA. CURRENT FCST HOURLY
TEMPS ARE A COUPLE OF DEG TWO LOW TO ISSUE AT THIS POINT...AND
WILL PUNT TO EVENING SHIFT TO ASSESS 00Z MODEL RUNS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 256 PM CDT WED JUL 17 2013
FRIDAY AND SATURDAY...NORTHWEST FLOW PATTERN BEHIND DEPARTING SYSTEM
WILL BRING A CHANCE FOR SOME ISOLATED SHOWERS/TSTMS ON
FRIDAY...MAINLY IN THE EAST...WITH MODELS DIFFERING ON TIMING.
SIGNIFICANT DIFFERENCES BETWEEN MID RANGE MODELS FOR END OF THE WEEK
ON INTO THE WEEKEND...WITH GFS DROPPING HIGH PRESSURE INTO THE
MANITOBA LAKES REGION WITH MUCH COOLER AIR FILTERING INTO NORTH
DAKOTA (UPPER 60S). ECMWF BRINGS HIGH PRESSURE FURTHER
EAST...ALLOWING RETURN FLOW/WARM ADVECTION TO BRING MAX TEMPS INTO
THE MID TO UPPER 70S. WILL KEEP CONSALL BLEND GOING FOR THIS
PERIOD..HOWEVER THINK GFS-LIKE TEMPS WOULD BE WISHFUL THINKING FOR
MID JULY. CONSALL IS ONLY SLIGHTLY COOLER THAN ECMWF...WHICH IS
STILL COOLER THAN SEASONAL NORMS...SO SATURDAY SHOULD BE PLEASANT
EITHER WAY.
SUNDAY-WEDNESDAY...UPPER FLOW WILL BE MORE NORTHWEST DURING THIS
PERIOD ACCORDING TO THE EXTENDED MODELS. SHORTWAVES WITHIN THIS
PATTERN WILL BE HARD TO TIME. ANTICIPATE A MOSTLY DRY PERIOD WITH
ISOLATED TO SCATTERED THUNDERSTORMS. THE BEST THUNDERSTORM CHANCES
APPEAR TO BE WITH A STRONGER FROPA ON MONDAY...ALTHOUGH COVERAGE
SHOULD BE LIMITED. TEMPERATURES WILL BE NEAR NORMAL VALUES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1142 PM CDT WED JUL 17 2013
ISSUE THIS TAF IS THUNDERSTORM TIMING AT EACH OF THE TAF SITES.
VERY HARD TO HAVE ANY GOOD TIMING AT ANY SITE...THUS WENT SOME
PERIODS OF VCTS RIGHT NOW...AND TIMING DOWN A TEMPO OR PREDOMINATE
PERIOD RIGHT NOW IS VERY DIFFICULT AND LET TAFS BE UPDATED AS
TIMING BECOMES MORE CONFIDENT. GENERALLY EXPECT ISOLD-SCT
CONVECTION NR DVL-GFK-TVF-BJI TAF SITES OVERNIGHT INTO
THURSDAY...WITH FARGO LESS CHANCE. WINDS TO STAY GENERALLY EAST
DVL-GFK-TVF INTO THURSDAY MORNING WITH WIND AT FARGO TURNING BACK
SOUTHERLY AS FRONT MOVES BACK NORTH.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...RIDDLE
SHORT TERM...SPEICHER
LONG TERM...TG/SPEICHER
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
139 AM EDT THU JUL 18 2013
.SYNOPSIS...
A LARGE AREA OF HIGH PRESSURE WILL CONTINUE TO DOMINATE THE
WEATHER ACROSS THE OHIO VALLEY THROUGH THURSDAY. THE HIGH WILL
BEGIN TO BREAK DOWN AND DRIFT SOUTH ON FRIDAY. THIS WILL ALLOW A
COLD FRONT TO DROP ACROSS THE AREA ON SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
TEMPS HAVE STARTED TO FALL SO HEAT ADVISORY HAS BEEN ALLOWED TO
EXPIRE FOR NOW. CONVECTION HAS DISSIPATED AGAIN THIS EVENING AS
EXPECTED. HRRR AND RUC DO ALLOW A BRIEF ISOLATED CONVECTIVE CELL TO
DEVELOP HERE AND THERE OVERNIGHT BUT OTHER THAN THE LEFTOVER CELLS
IN CANADA DROPPING SE TOWARD LERI THINK THE AIRMASS IS TOO CAPPED
FOR ANYTHING TO DEVELOP ELSEWHERE.
ANOTHER WARM AND MUGGY NIGHT. SOME PATCHY FOG MAY DEVELOP BUT NOT
EXPECTING A LOT.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY NIGHT/...
NO BIG CHANGES IN STORE FOR THURSDAY. CERTAINLY POSSIBLE TO GET A
ROGUE THUNDERSTORM WITH THE INSTABILITY SIMILAR TO TODAY BUT FOR
NOW WILL HAVE NO MENTION GIVEN LOW PROBABILITY. ISSUED A HEAT
ADVISORY FOR THURSDAY WITH HIGHS A DEGREE OR SO HIGHER DURING THE
AFTERNOON WITH SIMILAR DEWPOINTS. SHOULD AGAIN HAVE HEAT INDEX
CLOSE TO 100. THURSDAY NIGHT INTO FRIDAY WESTERLIES BEGIN TO
DESCEND ACROSS THE AREA AS UPPER HIGH AXIS SHIFTS SOUTH. WILL HAVE
SLIGHT CHANCE POPS FOR FRIDAY AFTERNOON AND THEN INCREASE TO HIGH
CHANCE AND LIKELY POPS IN ADVANCE OF AND WITH THE FRONT FRIDAY
NIGHT AND SATURDAY. TEMPS AROUND 90 OR A BIT HIGHER THURSDAY AND
FRIDAY. LOW TO MID 80S SATURDAY.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
HIGH PRESSURE ACROSS THE CENTRAL GREAT LAKES STAYS NORTH OF OUR
AREA...SLIDING EAST EARLY NEXT WEEK. THEREFORE AREA WILL GET A
REPRIEVE FROM RECENT HEAT AND TEMPERATURES WILL BE SITTING CLOSE TO
NORMALS. SUNDAY/SUNDAY NIGHT WILL BE DRY WITH HIGH PRESSURE
OVERHEAD...BUT LESS CERTAINTY INTO MONDAY AND TUESDAY WITH SOME
RETURNING MOISTURE TO THE AREA. THE BIG PICTURE KEEPS A MODERATE
TROUGH ACROSS THE NORTHERN TWO THIRDS OF THE EAST U.S. ANY TRUE
FRONTAL PASSAGE LOOKS TO HOLD OFF UNTIL MID WEEK.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
THERE WILL BE PATCHY MVFR FOG AGAIN AROUND SUNRISE. OTHERWISE
EXPECT VFR CONDITIONS THROUGH THE DAY WITH AFTERNOON CUMULUS. IF
ANY ISOLATED CONVECTION CAN DEVELOP IT APPEARS IT WILL BE EAST OF
A LINE FROM MENTOR TO YOUNGSTOWN.
.OUTLOOK...NON VFR IN PATCHY EARLY MORNING FOG.
&&
.MARINE...
HIGH PRESSURE ACROSS THE AREA SLOWLY WEAKENS THROUGH FRIDAY. A COLD
FRONT WILL BE CROSSING THE GREAT LAKES BETWEEN FRIDAY AND SATURDAY.
WINDS AHEAD OF THIS FRONT WILL PICK UP SOME...LIKELY GENERATING 3 TO
5 FOOT WAVES IN THE EASTERN OPEN WATERS FRIDAY AFTERNOON. SMALL
CRAFT ADV CONDITIONS FOR THE NEARSHORE WATERS WILL LIKELY BE DELAYED
UNTIL THE FRONTAL PASSAGE...FOR FRIDAY NIGHT AND SATURDAY.
SHOWERS/THUNDERSTORMS WILL ACCOMPANY THIS COLD FRONT. HIGH PRESSURE
FOLLOWS IN ITS WAKE OVER THE REST OF THE WEEKEND...KEEPING A LIGHTER
NORTH FLOW ACROSS LAKE ERIE.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 8 PM EDT THIS
EVENING FOR OHZ003-006>011-013-017>023-027>033-036>038-
047.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TK
NEAR TERM...ADAMS/TK
SHORT TERM...TK
LONG TERM...OUDEMAN
AVIATION...MULLEN
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1129 PM CDT WED JUL 17 2013
.UPDATE...FOR 06Z AVIATION FORECAST
&&
.AVIATION...
SHOWERS CONTINUE TO WORK WESTWARD INTO MIDDLE TENNESSEE. UPPER TROUGH
AXIS RUNNING UP ALONG PLATEAU AT 04Z WILL SHIFT WESTWARD OVERNIGHT.
ALTHOUGH CURRENT CONVECTION WILL LIKELY DIMINSH OVER THE NEXT
COUPLE OF HOURS DO THINK WE WILL LIKELY HAVE SOME CONVECTION IN
THE MID STATE DURING THE OVERNIGHT. MOISTURE DEEPENS WHILE OMEGA
INCREASES ON THURSDAY SO LOOK FOR SCATTERED SHOWERS AND
THUNDERSTORMS TO BE MORE NUMEROUS.
BOYD
&&
.PREV DISCUSSION... /ISSUED 1003 PM CDT WED JUL 17 2013/
UPDATE...
SCATTERED STORMS CONTINUE TO DEVELOP ALONG AND EAST OF THE CUMBERLAND
PLATEAU...WORKING SLOWLY WEST. UPPER HIGH CONTINUES TO LINGER OVER
THE MID-WEST/OH VALLEY BUT VERY WEAK INVERTED TROUGH/WAVE SHOWING
UP ACROSS THE APPALACHIANS HEADING WEST AS WELL. THIS WAVE MOVING
OVER THE CWA LITTLE LATER WILL DEEPEN MOISTURE SOME AS WELL AS KEEP
LARGE SCALE ACCENT GOING. CANT RULE OUT ISO TO POSSIBLY SCT STORMS
OVERNIGHT...ESPECIALLY EAST OF BNA. HAVE ADDED BACK FOR MOST OF
THE NIGHT. ALSO EXPECT STORMS TO DEVELOP FAIRLY EARLY TOMORROW
AFTER DYING OFF TOWARD MORNING...SO WILL ADJUST THERE AS WELL.
MINOR TEMP TWEAKS ALSO POSSIBLE.
PREV DISCUSSION... /ISSUED 805 PM CDT WED JUL 17 2013/
UPDATE...
AVIATION...
SHOWERS AND STORMS BEGINNING TO DEVELOP ON EAST SIDE OF PLATEAU
NEAR CROSSVILLE SO HAVE UPDATED TERMINAL FORECAST FOR CROSSVILLE
TO INCLUDE A CHANCE OF THUNDERSTORMS FOR THE NEXT SEVERAL HOURS.
LATEST RUC SHOWING UPPER LEVEL TROUGH OVER EASTERN TENNESSEE
APPROACHING PLATEAU.
BOYD
PREV DISCUSSION... /ISSUED 721 PM CDT WED JUL 17 2013/
UPDATE...FOR 00Z AVIATION FORECAST
AVIATION...
ISOLATED TO SCATTERED CONVECTION ON-GOING IN THE MID STATE AT THIS
TIME. THERE IS A PRETTY GOOD SWATH OF SHOWERS AND STORMS OVER
EASTERN TENNESSEE AND WESTERN CAROLINAS THAT MAY WORK WESTWARD
THIS EVENING AND OVERNIGHT INTO THE MID STATE. THIS ACTIVITY IS
ASSOCIATED WITH AN EASTERLY WAVE THATS BEEN PROGRESSING WESTWARD
WITH TIME. IF THIS TREND CONTINUES THIS ACTIVITY WILL REACH THE
PLATEAU AROUND 02Z-03Z AND CONTINUE WESTWARD LATE EVENING AND
OVERNIGHT. H-TRIPLE-R HI RES BRINGS THIS ACTIVITY UP TO INTERSTATE
65 BY 07Z. LOOK FOR SCATTERED CONVECTION DURING THE DAY ON
THURSDAY.
BOYD
PREV DISCUSSION... /ISSUED 541 PM CDT WED JUL 17 2013/
MESOSCALE UPDATE...
THUNDERSTORMS MOVING THROUGH GRUNDY COUNTY DROPPING RAINFALL OF
ONE TO 1.25 INCHES PER HOUR. STORMS SHOULD EXIT SHORTLY BUT WILL
HAVE TO WATCH UPSTREAM STORMS FOR TRAINING.
BOYD
PREV DISCUSSION... /ISSUED 309 PM CDT WED JUL 17 2013/
DISCUSSION...
CURRENT RADAR TRENDS INDICATE VERY ISOLATED SHOWERS ACROSS MIDDLE
TENNESSEE. VISIBLE SATELLITE IMAGERY SHOWS DIURNAL CU FIELD
DEVELOPED JUST AFTER 15Z TODAY...AND FIGURE THIS WILL BE THE TREND
OVER THE NEXT COUPLE OF DAYS BEFORE A FRONTAL BOUNDARY PUSHES DOWN
THIS WEEKEND. MODELS INDICATE A SLIGHT INCREASE IN MOISTURE FOR
THURSDAY AND FRIDAY...SO AM ANTICIPATING A CORRESPONDING SLIGHT
INCREASE IN SHOWER CHANCES THE NEXT TWO DAYS. UPSTREAM RADAR
TRENDS INDICATE A BROADER COVERAGE OF CONVECTION...AND EXPECT THIS
PATTERN TO SHIFT WESTWARD WHILE WEAKENING SOMEWHAT.
BETTER CHANCES FOR RAIN SHOWERS AND CONVECTION WILL BE THIS
WEEKEND AS FLOW SHIFTS AROUND TO THE SOUTHWEST AHEAD OF A WEAK
FRONTAL BOUNDARY THAT WILL PASS THROUGH BY SUNDAY EVENING. BEHIND
THE FRONT...THE FLOW REMAINS WESTERLY...SO EXPECT LITTLE IN THE
WAY OF RELIEF FROM THE WARM TEMPERATURES AND HUMIDITY. THE UPPER
TROUGH THAT IS EXPECTED TO SET UP OVER THE EASTERN HALF OF THE
U.S. WILL REMAIN IN PLACE THROUGH THE END OF THE FORECAST
PERIOD...WITH THE EXTENDED MODELS HINTING AT A RELIEF PERHAPS BY
NEXT WEEKEND.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION
NWS SPOKANE WA
230 AM PDT Thu Jul 18 2013
.SYNOPSIS...
A prolonged period of dry weather is expected over the Inland
Northwest. No precipitation is anticipated for at least the next
seven days. Temperatures will be seasonably warm this weekend into
next week.
&&
.DISCUSSION...
Thursday through Friday night: A low amplitude ridge of high
pressure will be over the Inland NW to end the work week promoting
mostly clear skies and above normal warmth. Temperatures in
general will be warming into the 90`s for most valleys with light,
terrain driven winds. A broad upper-level low extending west from
central Canada will prevent the jet stream from migrating much
further north then the WA/BC border. This will keep a pool of
instability over southern BC...and perhaps into the extreme
northern mountains of WA. The threat is low but does exist and NAM
continues to indicate enough surface based instability over the
Pasayten Wilderness with the 00z model suite to support a stray
thunderstorm. Given its bias for placing instability over this
area...we have kept thunder mention out of the forecast but will
do another analysis in the morning to see how models and HRRR are
handling the boundary layer moisture with the idea that we may
need to include an isolated threat. /sb
Saturday through Monday: The biggest change to the forecast for
the weekend was to lower temperatures a few degrees. A couple of
days ago, the medium range models were suggesting a stronger upper
ridge for Saturday and Sunday. They have now trended toward a
flatter 500mb flow pattern. Afternoon temperatures Saturday
through Monday will still be above average, but not as hot as
previously thought. The air mass will be exceedingly dry. Model
cross sections for the weekend into Monday show very little chance
for clouds. The dry westerly flow Saturday and Sunday will likely
cause surface dewpoints to plunge into the 20s and low 30s. Some
of the driest air we have experienced this summer. The warm and
dry conditions will continue to cure the fuels in the higher
elevations bringing our region into the heart of the wildfire
season. /GKoch
Tuesday through Thursday: Models seem to initialize this period
rather well with a low pressure system off of the northern BC
coast and zonal flow coming around the low and into our region.
With the low having a cooler source region for moisture models
are not showing any significant chance of precipitation at this
time. The feature to watch will be the movement of the mentioned
low over the latter part of the week. The Euro and GEM both have
it moving towards land that would allow for increased winds
earlier whereas the GFS holds off on that movement and slowly
moves it down the BC coast which would bring winds to our
region...but at a later time. Depending on the track will also
determine if precip chances need updated with the associated
moisture and cold pool interactions that would likely take place.
This low will be an important feature to keep an eye on as it
could play a large role in the winds and precip chances for our
area. Stronger winds coupled with the forecasted low RH values
could lead to fire weather concerns and potentially highlights.
With this being in the far extended I leaned toward the more
consistent model in the GFS that would promote the zonal flow for
a longer period. Temperatures look to hold steady in the mid 80s
and low 90s for most making for pleasant conditions in the middle
part of next week. /Fliehman
&&
.AVIATION...
06Z TAFS: VFR conditions are expected through 06z Friday. Other
than flat cumulus over the mountains near the Canadian border
Thursday afternoon...skies are expected to remain generally clear
except for a few mid level accus clouds over Northeast Washington
and North Idaho tonight. JW
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 89 60 92 62 91 59 / 0 0 0 0 0 0
Coeur d`Alene 90 55 91 57 90 56 / 0 0 0 0 0 0
Pullman 88 47 90 49 90 51 / 0 0 0 0 0 0
Lewiston 95 61 98 63 97 63 / 0 0 0 0 0 0
Colville 92 54 93 56 94 55 / 0 0 0 0 0 0
Sandpoint 87 50 88 52 89 51 / 0 0 0 0 0 0
Kellogg 87 55 90 57 89 56 / 0 0 0 0 0 0
Moses Lake 94 57 97 59 97 60 / 0 0 0 0 0 0
Wenatchee 93 65 95 67 95 62 / 0 0 0 0 0 0
Omak 94 55 97 57 96 59 / 0 0 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS TUCSON AZ
910 AM MST THU JUL 18 2013
.SYNOPSIS...EXPECT SCATTERED THUNDERSTORMS MAINLY SOUTH AND
NORTHEAST OF TUCSON THROUGH TONIGHT. A LOW PRESSURE SYSTEM MOVING
SOUTH OF THE AREA WILL THEN ENHANCE THUNDERSTORM CHANCES STARTING
FRIDAY AND CONTINUING INTO THIS WEEKEND. THEREAFTER...THE NORMAL
CYCLE OF SCATTERED AFTERNOON AND EVENING THUNDERSTORMS WILL RETURN
BY THE MIDDLE OF NEXT WEEK. DAYTIME TEMPERATURES WILL BE SEVERAL
DEGREES BELOW NORMAL AS WELL.
&&
.DISCUSSION...VISIBLE SATELLITE IMAGERY AND SURFACE OBSERVATIONS
INDICATE A FEW TO SCATTERED MAINLY MID-LEVEL CLOUDS ACROSS SE AZ AT
THIS TIME. DEWPOINTS VALID 16Z RANGED MOSTLY FROM THE MID 50S-LOWER
60S F. THESE TEMPS WERE ABOUT 5 DEGS F LOWER FROM TUCSON WESTWARD
VERSUS 24 HOURS AGO...BUT DEWPOINTS WERE ABOUT 5 DEGS F HIGHER EAST
OF TUCSON. SURFACE TEMPS VALID 16Z WERE NEARLY IDENTICAL TO THIS
TIME WED.
18/12Z KTWC SOUNDING DEPICTED A DRIER REGIME VERSUS 24 HOURS...WITH
TOTAL PRECIP WATER OF 1.35 INCHES. A MARGINALLY UNSTABLE REGIME ALSO
EXISTED WITH LIFTED INDEX OF MINUS 2 AND MINIMAL CAPE. A FAIRLY
PRONOUNCED CAPPING INVERSION WAS NOTED AROUND 500 MB. BLENDED TOTAL
PRECIP WATER IMAGERY PRODUCT YIELDED VALUES RANGING FROM NEAR 1.25
INCHES EAST TO 1.40 INCHES ACROSS THE WESTERN DESERTS. 18/12Z UPPER
AIR PLOTS INDICATED 588 DM LOW PRESSURE CENTERED NEAR THE FAR SE AZ/
FAR SW NEW MEXICO BORDER...AND STRONG RIDGE THAT EXTENDED FROM THE
GREAT BASIN EWD INTO THE MID ATLANTIC/TIDEWATER REGIONS. LIGHT TO
MODERATE NLY/NELY FLOW ALOFT PREVAILED ACROSS MUCH OF SE AZ.
UPPER LOW IS PROGGED TO MOVE SLOWLY SW INTO NRN SONORA BY FRI
MORNING. 18/13Z RUC HRRR DEPICTS THE FAVORED AREAS FOR SCATTERED
SHOWERS/TSTMS TO OCCUR INTO EARLY THIS EVENING TO BE SOUTH OF TUCSON
ACROSS SRN COCHISE/SANTA CRUZ COUNTIES...AND NE OF TUCSON ACROSS NRN
GREENLEE AND GRAHAM COUNTIES. GIVEN THE AFOREMENTIONED CAPPING
INVERSION...BELIEVE CONVECTIVE ACTIVITY ESPECIALLY FOR THE TUCSON
METRO AREA WILL BE LIMITED UNTIL EARLY THIS EVENING. GIVEN THE
GENERALLY DRIER REGIME VERSUS 24 HOURS AGO...THE THREAT FOR HEAVY
RAINFALL SHOULD BE MITIGATED. BRIEF WIND GUSTS TO AROUND 40 MPH MAY
OCCUR WITH THE STRONGER THUNDERSTORMS...SIMILAR TO SPEEDS RECORDED AT
KSAD WED AFTERNOON.
THERE ARE NO UPDATES PLANNED FOR THE OFFICIAL FORECAST AT THIS TIME.
PLEASE REFER TO THE PREVIOUS DISCUSSION SECTION BELOW FOR ADDITIONAL
DETAIL.
&&
.PREV DISCUSSION /207 AM MST THU JUL 18 2013/...MODELS INDICATE THAT
THE LOW WILL CONSOLIDATE OVER THE GENERAL VICINITY OF THE CENTRAL
GULF OF CALIFORNIA BY LATE FRIDAY AFTERNOON. AS THIS OCCURS THE
UPPER HIGH...WHICH IS CURRENTLY OVER UTAH AND COLORADO WILL DRIFT
WEST OVER NEVADA WITH A RIDGE AXIS EXTENDING EAST INTO THE CENTRAL
PLAINS. THIS SETUP WILL RESULT IN AN EASTERLY COMPONENT TO THE WINDS
THROUGH AT LEAST THE WEEKEND. WINDS WILL TAKE ON A MORE SOUTH TO
SOUTHEASTERLY COMPONENT DURING THE EARLY TO MIDDLE OF NEXT WEEK AS
THE UPPER HIGH OVER NEVADA BEGINS MOVING EAST AND SETTLES OVER THE
CENTRAL TO SOUTHERN PLAINS BY THE MIDDLE OF NEXT WEEK.
MODELS ADVERTISE A VERY LARGE SWATH OF HIGH PW AIR MAKING ITS WAY UP
THE GULF OF CALIFORNIA AND INTO SOUTHWEST ARIZONA AS THE UPPER LOW
MOVES ACROSS NORTHERN MEXICO. PW`S ARE ADVERTISED TO BE ABOVE THE 2
INCH MARK OVER THE GULF OF CALIFORNIA AND WILL MAKE IT INTO
SOUTHWEST ARIZONA BY LATE FRIDAY OR EARLY SATURDAY. IN ADDITION...
MODELS SHOW THE BEST FORCING AND MOISTURE TRANSPORT TO BE ALONG THE
INTERNATIONAL BORDER BEGINNING FRIDAY AND CONTINUING THROUGH THE
WEEKEND. THAT SAID...I TWEAKED POPS UP A TAD ALONG THE BORDER AND
OUT WEST OVER THE TOHONO O`ODHAM NATION...SINCE STEERING WINDS WILL
PUSH ANY CONVECTION THAT DEVELOPS IN THAT DIRECTION. SO INSTEAD OF
THE TYPICAL 10-20% POP FOR THE CENTRAL AND WESTERN PORTIONS OF PIMA
COUNTY...WE WILL SEE MORE OF A SOLID CHANCE CATEGORY POP FOR THIS
AREA WITH LIKELY POPS IN A FEW PLACES RIGHT ALONG THE INTERNATIONAL
BORDER...ESPECIALLY ON SATURDAY.
DURING THE EARLY TO MIDDLE OF NEXT WEEK AS THE HIGH SHIFTS EAST OVER
THE PLAINS...THE MOISTURE WILL DECREASE AND WE WILL SEE MOSTLY
ISOLATED SHOWER/THUNDERSTORM ACTIVITY WITH SCATTERED POPS FOR THE
MOUNTAINS.
HIGHS GENERALLY 3 TO 7 DEGS BELOW NORMAL THROUGH TUESDAY...WITH THE
COOLEST DAYS BEING THIS WEEKEND WHEN HIGHS WILL BE ABOUT 5 TO 7 DEGS
BELOW NORMAL. ONLY SLIGHTLY BELOW NORMAL HIGHS FOR NEXT WEDNESDAY.
LOWS NEAR OR SLIGHTLY ABOVE NORMAL THROUGH NEXT TUESDAY...THEN ABOUT
3 TO 5 DEGS ABOVE NORMAL FOR WEDNESDAY MORNING.
&&
.AVIATION...EXPECT SCATTERED TSRA/SHRA ACROSS SE AZ THRU THIS
EVENING. THE FAVORED AREAS FOR PRECIP WILL BE SOUTH OF KTUS...
ESPECIALLY NEAR KDUG AND KOLS AND ACROSS NORTHERN GREENLEE AND
GRAHAM COUNTIES NE OF KTUS. MVFR CONDITIONS AND WIND GUSTS TO ABOUT
40 KTS WILL OCCUR WITH THE STRONGER THUNDERSTORMS. A FEW LINGERING
-SHRA LATE TONIGHT INTO FRIDAY MORNING. OTHERWISE...CLOUD DECKS THIS
MORNING GENERALLY ABOVE 12K FT AGL BECOMING 8-12K FT AGL THIS
AFTERNOON AND CONTINUING INTO FRIDAY MORNING. SURFACE WIND INTO
FRIDAY MORNING OR THRU 19/18Z ELY/SELY 5-15 KTS. SOMEWHAT STRONGER
WINDS ESPECIALLY VICINITY KTUS THRU FRIDAY MORNING. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...AMPLE MOISTURE IN COMBINATION WITH AN EASTERLY FLOW
REGIME WILL PROVIDE SCATTERED SHOWERS AND THUNDERSTORMS INTO THE
MIDDLE OF NEXT WEEK. THE STRONGER THUNDERSTORMS WILL BE CAPABLE OF
PRODUCING HEAVY DOWNPOURS AS WELL AS GUSTY AND ERRATIC WINDS.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
DISCUSSION/AVIATION...FRANCIS
PREVIOUS DISCUSSION...MOLLERE
FIRE WEATHER...MEADOWS/HUMPHREYS
AREA FORECAST DISCUSSION
NWS PUEBLO CO
325 PM MDT THU JUL 18 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 323 PM MDT THU JUL 18 2013
MAIN CONCERN IS THE POTENTIAL FOR HEAVY RAIN MAINLY ON FRIDAY. THIS
AFTERNOON...WATER VAPOR IMAGERY IS SHOWING THE MSTR PLUME MAINLY OVR
FAR WRN CO...BUT PLENTY OF SHOWERS AND TSTMS HAVE POPPED UP ALONG
THE CONTDVD. SOME OF THE STORMS HAVE BRIEFLY BEEN STRONG...LIKELY
PRODUCING SMALL HAIL AND HEAVY RAIN. OVR THE ERN MTS...SO FAR THERE
HAVE ONLY BEEN SOME ISOLD STORMS. STEERING FLOW ALOFT IS EASTERLY
AND THUS THE STORMS ARE MOVING TOWARD THE WEST. NOT EXPECTING
CONVECTION TO DEVELOP OVR THE SERN PLAINS...BUT LOCATIONS ALONG THE
I-25 CORRIDOR WILL PROBABLY SEE SOME ACTIVITY THIS EVENING. THE NAM
HAS BEEN CONSISTENT IS SHOWING SCT PCPN DEVELOPING THIS EVENING OVR
EL PASO AND PUEBLO COUNTIES...WHILE THE HRRR AND RAP13 SHOW ONLY
SOME ISOLD ACTIVITY. THERE IS THE POTENTIAL THIS EVENING FOR
STRONGER STORMS TO PRODUCE HEAVY RAIN...SO WL HAVE TO KEEP AN EYE ON
ANYTHING THE DEVELOPS OR MOVES OVR THE ANY OF THE BURN SCARS. AFTER
MIDNIGHT THERE COULD BE JUST SOME ISOLD SHOWERS/TSTMS LINGERING THRU
THE NIGHT IN A FEW AREAS...BUT THE CENTRAL MTS...TELLER...EL
PASO...FREMONT AND PUEBLO COUNTIES WL HAVE THE BEST CHANCES OF
SEEING SOME LINGERING CONVECTION.
MODELS SHOWING A SFC LOW DEVELOPING OVR THE SE CORNER OF
CO...CAUSING THE SFC WINDS TO BE NORTHEASTERLY UPSLOPE...AND LOW
LEVEL MSTR WL BE IN PLACE AS WELL. MODELS ARE STILL CONSISTENT
ON DEVELOPING PCPN IN THE MORNING HOURS OF FRI ALONG THE I-25
CORRIDOR AND THE HYR TRRN...WITH SOME ACTIVITY OVR THE FAR SERN
PLAINS BY LATE AFTERNOON. PRECIPITABLE WATER VALUES ARE NOT
FORECAST TO BE AS HIGH FOR FRI AS WHAT THEY WERE SHOWING THE LAST
COUPLE DAYS FOR FRI...AND NOT AS HIGH AS THEY WERE WHEN THERE WAS
FLASH FLOODING LAST WEEKEND. HOWEVER...THERE WILL STILL BE THE
POTENTIAL FOR LOCALLY HEAVY RAIN WITH STRONGER STORMS ON FRI AND
THUS FLASH FLOODING IS STILL A CONCERN...ESPECIALLY OVR THE BURN
SCARS. THE FLOW ALOFT ON FRI WL BE NORTH TO NORTHEAST AND THUS
STORMS ARE EXPECTED TO MOVE TOWARD THE SOUTH OR SOUTHWEST.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 323 PM MDT THU JUL 18 2013
LONGER TERM METEOROLOGICAL CHALLENGES INCLUDES POPS AND
TEMPERATURES. FRIDAY NIGHT INTO SATURDAY SATURDAY SHOULD
EXPERIENCE CONTINUED ELEVATED POPS(ESPECIALLY OVER SOUTHERN AND
WESTERN SECTIONS) AS WELL AS NEAR SEASONAL TEMPERATURES BEFORE
SOMEWHAT WARMER AND DRIER CONDITIONS DEVELOP OVER THE FORECAST
DISTRICT FROM LATER IN THE WEEKEND INTO NEXT WEEK.
LATEST LONGER TERM COMPUTER SIMULATIONS AND FORECAST SOUNDINGS
INDICATE THAT ROUNDS OF BASICALLY SCATTERED SHOWERS AND
THUNDERSTORMS CAPABLE OF PRODUCING LOCALLY HEAVY RAIN AND BURN
SCAR ISSUES(ESPECIALLY OVER WESTERN AND SOUTHERN SECTIONS) WILL BE
POSSIBLE FROM FRIDAY NIGHT INTO SATURDAY NIGHT IN WAKE OF
NORTHERLY SURGE ALLOWING INCREASED ATMOSPHERIC MOISTURE/PRECIPITABLE
WATER VALUES. WFO PUEBLO WILL CONTINUE TO MONITOR CLOSELY.
THEN...A DEVELOPING RIDGE OF HIGH PRESSURE INITIALLY CENTERED OVER
WESTERN NEVADA AT 00Z MONDAY IS PROJECTED TO BECOME CENTERED OVER
SOUTHERN COLORADO BY 00Z THURSDAY BEFORE SHIFTING SOUTHEAST INTO
THE TEXAS PANHANDLE BY 00Z FRIDAY.
AS THIS OCCURS...ANTICIPATE THAT POPS WILL BECOME MORE ISOLATED
FROM SUNDAY INTO NEXT WEEK IN COMBINATION WITH WARMER TEMPERATURES.
SPEAKING OF TEMPERATURES...NEAR SEASONAL MAXIMUM TEMPERATURES ARE
ANTICIPATED SATURDAY WITH ABOVE SEASONAL MAXIMUM TEMPERATURES THEN
PROJECTED OVER THE FORECAST DISTRICT FROM SUNDAY INTO THURSDAY.
MAXIMUM TEMPERATURES OVER PORTIONS OF THE SOUTHEASTERN PLAINS MAY
CHALLENGE THE CENTURY MARK AT TIMES...ESPECIALLY FROM MONDAY INTO
THURSDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 323 PM MDT THU JUL 18 2013
EXPECTING VFR CONDITIONS AT KPUB...KCOS AND KALS THROUGH THE
PERIOD. THERE COULD BE SOME SHOWERS/TSTMS IN THE VCNTY OF KCOS AND
KALS AFTER 23Z...AND POSSIBLY NR KPUB AFTER 02Z. SHOWER/TSTM
ACTIVITY SHOULD END AT THE TERMINAL SITE BY 06Z. IT LOOKS LIKE AN
EARLY SHOW IN FRIDAY...WITH THE POTENTIAL FOR SHOWERS/TSTMS AT THE
TAF SITES MAINLY AFTER 15Z. ON FRI THERE COULD BE SOME BRIEF HEAVY
RAIN AT THE TAF SITES WHICH COULD CAUSE MVFR/IFR CONDITIONS.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
319 PM MDT THU JUL 18 2013
.SHORT TERM...SLOW MOVING THUNDERSTORMS AN ISSUE OVER LARIMER
COUNTY THIS AFTN. FLASH FLOODING REPORTED IN THE FERN LAKE BURN
SCAR THIS AFTN WHERE RADAR ESTIMATED 1.5 TO 2.5 INCH STORM TOTALS.
SIMILAR ISSUES WILL CONTINUE THE REST THE AFTERNOON AND EVENING
ESPECIALLY IN THE FOOTHILLS OF LARIMER AND BOULDER COUNTIES. STORM
MOTIONS 10 KTS OR LESS THIS AFTN WITH PW VALUES CLOSE TO ONE INCH.
16Z HRRR KEEPS THE BEST CONVERAGE ALONG AND NORTH OF INTERSTATE
70 AND 76 TONIGHT...SO WILL GO WITH THE HIGHEST COVERAGE THERE. ON
FRIDAY IT WILL BE COOLER FOLLOWING THE PASSAGE OF A COLD FRONT
TONIGHT. SPATIAL CROSS SECTIONS SHOW A DEEPER EASTERLY FLOW WITH
SIMILAR PW VALUES FOR FRIDAY AFTN. AS A RESULT...SLOW MOVING
THUNDERSTORMS WITH HEAVY RAIN AND FLASH FLOODING WILL AGAIN BE AN
ISSUE ESPECIALLY IN THE BURN AREAS...BUT IN OTHER POOR DRAINAGE
AREAS AS WELL. NO FLASH FLOOD WATCH AT THIS TIME...BUT ONE MAY
BE NEEDED FOR FRIDAY AT SOME POINT.
.LONG TERM...ONLY MINOR CHANGES TODAY. UPPER RIDGE REMAINS OVER
MOST OF THE COUNTRY. DRIER AIR WORKS IN FROM THE NORTHWEST ON
SUNDAY FOR WARMER AND NEARLY DRY WEATHER...THEN BY LATE IN THE
WEEK MOISTURE COMES UP FROM THE SOUTH AGAIN. THIS IS ALREADY
COVERED WELL...MINOR CHANGES IN MODEL CONSENSUS LOOK FINE.
&&
.AVIATION...16Z HRRR MDL WANT TO KEEP THE HIGHEST TSTM COVERAGE
TO THE NORTH AND WEST OF DENVER THIS EVENING SO IT MAY BE BEST TO
GO WITH VCTS THIS AFTN SO HOLD OFF ON THE TEMPO GROUP FOR TSTMS
FOR THE 00Z TAFS. WILL WATCH THE NEXT COUPLE OF HRRR RUNS AND SEE
HOW THEY HANDLE OUTFLOW BOUNDARIES AND THE CONSEQUENT CONVECTION
OFF THE FOOTHILLS BEFORE MAKING A DECISION. A COOLER AMS WILL BE
OVER THE AREA ON FRIDAY FOLLOWING THE COLD FRONT TONIGHT. FLOW AT
THE SFC AND ALOFT WILL BE EASTERLY FOR FRIDAY AFTN...WITH A BETTER
CHANCE OF TSTMS WEST OF INTERSTATE 25.
&&
.HYDROLOGY...THREAT FOR FLASH FLOODING WILL BE AN ISSUE IN THROUGH
04Z THIS EVENING...WITH ANOTHER POSSIBILITY FOR FLASH FLOODING IN
THE BURN AREAS FRIDAY AFTN. STORM MOTIONS A LITTLE ERRATIC THIS
AFTN WITH SPEEDS OF 6-10KTS...WITH SLOW MOVEMENT AGAIN EXPECTED
FRIDAY AFTN WITH STORM MOTION EXPECTED TO BE NE TO SW.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...COOPER
LONG TERM....GIMMESTAD
AVIATION...COOPER
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
955 AM MDT THU JUL 18 2013
.UPDATE...I DECIDED TO INCREASE THE POPS ALONG THE URBAN CORRIDOR
LATE THIS AFTN AND EVENING. STILL SCATTERED IN TERMS OF COVERAGE
BUT SLIGHTLY HIGHER POPS.
&&
.PREV DISCUSSION... /ISSUED 905 AM MDT THU JUL 18 2013/
UPDATE...CURRENT FORECAST LOOKS ON TRACK SO NO CHANGES PLANNED AT
THIS TIME.
&&
.AVIATION...LATEST HRRR INDICATE TSTMS DEVELOPING OVER THE DENVER
AREA AROUND 22Z-04Z WINDOW. ALL THE MDLS GENERATE A PERIOD OF QPF
OVER THE DENVER AREA AT THAT TIME. PLENTY OF MOISTURE AND INSTBY
AROUND SO OPTED TO ADD VCTS FOR THIS TIME FRAME WITH A TEMPO GROUP
FOR TSRA AS WELL. PULSE TYPE THUNDERSTORMS WITH MODERATE TO HEAVY
RAIN THE MAIN THREAT...COULD SEE BRIEF PERIOD OF MVFR CIGS/VSBYS
IN THE HEAVIER RAIN SHOWERS. OTHERWISE NO OTHER CHANGES TO THE
REST OF THE TAF AT THIS TIME.
.PREV DISCUSSION... /ISSUED 354 AM MDT THU JUL 18 2013/
SHORT TERM...PRECIPITABLE WATER VALUES HAVE INCREASED 0.10 TO
0.25 INCH FROM 24 HOURS AGO...WITH VALUES AROUND 1.0 INCH ALONG
THE FRONT RANGE. MOISTURE SHOULD CONTINUE TO SLOWLY INCREASE
THROUGH THE AFTERNOON/TONIGHT AS UPPER LEVEL MOISTURE PLUME SHIFTS
EAST/SOUTHEAST FROM WYOMING/NORTHWEST COLORADO. AIRMASS WARMS
ENOUGH IN THE LOW LEVELS TO BREAK INVERSIONS IN THE MOUNTAINS BY
LATE THIS MORNING AND THEN ON THE PLAINS BY MID/LATE AFTERNOON.
MOST SHORT RANGE MODELS SUGGEST A CONVERGENCE ZONE FROM STALLING
SURFACE TROUGH WILL SET UP FROM NEAR THE PALMER DIVIDE NORTHEAST
ACROSS THE PLAINS BY LATE AFTERNOON WHICH WOULD AID LOW LEVEL
MOISTURE CONVERGENCE AND STORM DEVELOPMENT AS WELL. CAPES ARE
LIMITED TO LESS THAN 1000 J/KG AND LITTLE IF ANY SHEAR SO EXPECT
PULSE OUTFLOW DOMINATED STORMS. THEY WILL STILL PRODUCE BRIEF VERY
HEAVY RAIN DUE TO INCREASED PRECIPITABLE WATER.
TEMPERATURES ON THE PLAINS WILL STILL BE A FEW DEGREES WARMER
THAN YESTERDAY DESPITE THE INCREASE IN CLOUD COVER BY THIS
AFTERNOON.
FOR LATER TONIGHT...STORM THREAT WILL GRADUALLY DIMINISH AS
AIRMASS STABILIZES. THERE IS STILL WEAK Q-G LIFT NOTED SO CANT
TOTALLY RULE OUT A STORM OR TWO LINGERING PAST MIDNIGHT.
LONG TERM...THE SURFACE LOW WILL CONTINUE MOVING SOUTH INTO
SOUTHEASTERN COLORADO FRIDAY ALLOWING SURFACE WINDS TO BECOME
NORTHEASTERLY UPSLOPE. WITH PRECIPITABLE WATER VALUES OF 1-1.25
INCHES ACROSS THE PLAINS AND 0.7-1 INCH OVER THE HIGHER
TERRAIN...EXPECTING NUMEROUS SHOWERS AND THUNDERSTORMS OVER THE
EASTERN FRONT RANGE MOUNTAINS AND FOOTHILLS AND AT LEAST SCATTERED
COVERAGE OVER THE PLAINS. THESE STORMS WILL BE ABLE TO PRODUCE
BRIEF HEAVY RAIN...SO WILL HAVE TO KEEP AN EYE ON THE FOOTHILLS
AND OLD BURN SCARS. TEMPERATURES FRIDAY WILL BE ABOUT 5-10 DEGREES
COOLER THAN TODAYS READINGS.
ON SATURDAY...A LITTLE EXTRA PUSH OF MOISTURE FROM THE EAST WILL
ALLOW A THETA E RIDGE TO MOVE OVER THE PLAINS AND PRODUCE ANOTHER
DAY OF SCATTERED THUNDERSTORMS. HOWEVER THESE WILL BE SLIGHTLY
DRIER AND SHOULD DIE OFF LATER IN THE EVENING AS DRIER AIR MOVES
IN FROM THE NORTH. TEMPERATURES SATURDAY WILL WARM A COUPLE
DEGREES...HOWEVER IT MAY BE VERY SIMILAR TO FRIDAY DEPENDING ON
CLOUD COVER.
SUNDAY AND MONDAY WILL FEATURE WARMER AND MOSTLY DRY WEATHER AS
THE UPPER RIDGE WHICH HAD BEEN PUSHED WEST OVER CALIFORNIA BUILDS
BACK EAST. THIS WILL BRING TEMPERATURES BACK TO AND ABOVE NORMALS
FOR MID TO LATE JULY. MODELS THEN SHOW A WEAK SHORTWAVE TROUGH TO
DROP OUT OF THE PACIFIC NORTHWEST FOR TUESDAY AND WEDNESDAY. THIS
WILL BRING COOLER AND WETTER WEATHER FOR THESE DAYS...WITH SHOWERS
MAINLY OVER THE HIGH TERRAIN TUESDAY THEN SPREADING OVER THE
PLAINS WEDNESDAY.
AVIATION...VFR CONDITIONS WILL PERSIST THROUGH TONIGHT. WINDS
WILL TURN LIGHT WEST/NORTHWEST BY 15Z-17Z THIS MORNING AND THEN
MORE NORTHERLY BY AFTERNOON. SOME GUSTS TO 20 KTS POSSIBLE AFTER
18Z. STORM CHANCES WILL BE HIGHER TODAY...PROBABLY ENOUGH TO
WARRANT AT LEAST A TEMPO GROUP FOR GUSTY OUTFLOW WINDS TO 30-40
KTS. MAIN THREAT WOULD BE 21Z-04Z. SLIGHT CHANCE OF A STRONG
ENOUGH STORM MOVING DIRECTLY OVER THE AIRPORT TO REDUCE VSBYS
TO 3-4SM.
HYDROLOGY...PRECIPITABLE WATER VALUES HAVE ALREADY INCREASED TO
AROUND 1.0 INCH ALONG THE FRONT RANGE. SEE THESE VALUES INCREASING
SLIGHTLY THROUGH THE DAY. AS A RESULT...LOCALLY HEAVY RAIN
POSSIBLE WITH ALL STORMS ESPECIALLY SINCE THEY WILL BE SLOW
MOVING. HOWEVER...WARM CLOUD DEPTH IS LIMITED TO JUST A COUPLE
THOUSAND FEET GIVEN HIGH FREEZING LEVELS...AND RELATIVELY DEEP
SUBCLOUD LAYER WILL LIKELY RESULT IN OUTFLOW DOMINATED STORMS.
MAIN THREAT FOR ANY FLOODING CONCERNS WILL BE IN THE FRONT RANGE
BURN SCARS...SO WILL HAVE TO MONITOR THOSE CLOSELY THIS
AFTERNOON/EVENING. THREAT LOW ENOUGH TO PRECLUDE A FLASH FLOOD
WATCH AT THIS TIME...BUT WILL HIGHLIGHT LOCALLY HEAVY RAINFALL IN
HAZARDOUS WEATHER OUTLOOK.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...COOPER
LONG TERM....KRIEDERMAN
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
905 AM MDT THU JUL 18 2013
.UPDATE...CURRENT FORECAST LOOKS ON TRACK SO NO CHANGES PLANNED AT
THIS TIME.
&&
.AVIATION...LATEST HRRR INDICATE TSTMS DEVELOPING OVER THE DENVER
AREA AROUND 22Z-04Z WINDOW. ALL THE MDLS GENERATE A PERIOD OF QPF
OVER THE DENVER AREA AT THAT TIME. PLENTY OF MOISTURE AND INSTBY
AROUND SO OPTED TO ADD VCTS FOR THIS TIME FRAME WITH A TEMPO GROUP
FOR TSRA AS WELL. PULSE TYPE THUNDERSTORMS WITH MODERATE TO HEAVY
RAIN THE MAIN THREAT...COULD SEE BRIEF PERIOD OF MVFR CIGS/VSBYS
IN THE HEAVIER RAIN SHOWERS. OTHERWISE NO OTHER CHANGES TO THE
REST OF THE TAF AT THIS TIME.
&&
.PREV DISCUSSION... /ISSUED 354 AM MDT THU JUL 18 2013/
SHORT TERM...PRECIPITABLE WATER VALUES HAVE INCREASED 0.10 TO
0.25 INCH FROM 24 HOURS AGO...WITH VALUES AROUND 1.0 INCH ALONG
THE FRONT RANGE. MOISTURE SHOULD CONTINUE TO SLOWLY INCREASE
THROUGH THE AFTERNOON/TONIGHT AS UPPER LEVEL MOISTURE PLUME SHIFTS
EAST/SOUTHEAST FROM WYOMING/NORTHWEST COLORADO. AIRMASS WARMS
ENOUGH IN THE LOW LEVELS TO BREAK INVERSIONS IN THE MOUNTAINS BY
LATE THIS MORNING AND THEN ON THE PLAINS BY MID/LATE AFTERNOON.
MOST SHORT RANGE MODELS SUGGEST A CONVERGENCE ZONE FROM STALLING
SURFACE TROUGH WILL SET UP FROM NEAR THE PALMER DIVIDE NORTHEAST
ACROSS THE PLAINS BY LATE AFTERNOON WHICH WOULD AID LOW LEVEL
MOISTURE CONVERGENCE AND STORM DEVELOPMENT AS WELL. CAPES ARE
LIMITED TO LESS THAN 1000 J/KG AND LITTLE IF ANY SHEAR SO EXPECT
PULSE OUTFLOW DOMINATED STORMS. THEY WILL STILL PRODUCE BRIEF VERY
HEAVY RAIN DUE TO INCREASED PRECIPITABLE WATER.
TEMPERATURES ON THE PLAINS WILL STILL BE A FEW DEGREES WARMER
THAN YESTERDAY DESPITE THE INCREASE IN CLOUD COVER BY THIS
AFTERNOON.
FOR LATER TONIGHT...STORM THREAT WILL GRADUALLY DIMINISH AS
AIRMASS STABILIZES. THERE IS STILL WEAK Q-G LIFT NOTED SO CANT
TOTALLY RULE OUT A STORM OR TWO LINGERING PAST MIDNIGHT.
LONG TERM...THE SURFACE LOW WILL CONTINUE MOVING SOUTH INTO
SOUTHEASTERN COLORADO FRIDAY ALLOWING SURFACE WINDS TO BECOME
NORTHEASTERLY UPSLOPE. WITH PRECIPITABLE WATER VALUES OF 1-1.25
INCHES ACROSS THE PLAINS AND 0.7-1 INCH OVER THE HIGHER
TERRAIN...EXPECTING NUMEROUS SHOWERS AND THUNDERSTORMS OVER THE
EASTERN FRONT RANGE MOUNTAINS AND FOOTHILLS AND AT LEAST SCATTERED
COVERAGE OVER THE PLAINS. THESE STORMS WILL BE ABLE TO PRODUCE
BRIEF HEAVY RAIN...SO WILL HAVE TO KEEP AN EYE ON THE FOOTHILLS
AND OLD BURN SCARS. TEMPERATURES FRIDAY WILL BE ABOUT 5-10 DEGREES
COOLER THAN TODAYS READINGS.
ON SATURDAY...A LITTLE EXTRA PUSH OF MOISTURE FROM THE EAST WILL
ALLOW A THETA E RIDGE TO MOVE OVER THE PLAINS AND PRODUCE ANOTHER
DAY OF SCATTERED THUNDERSTORMS. HOWEVER THESE WILL BE SLIGHTLY
DRIER AND SHOULD DIE OFF LATER IN THE EVENING AS DRIER AIR MOVES
IN FROM THE NORTH. TEMPERATURES SATURDAY WILL WARM A COUPLE
DEGREES...HOWEVER IT MAY BE VERY SIMILAR TO FRIDAY DEPENDING ON
CLOUD COVER.
SUNDAY AND MONDAY WILL FEATURE WARMER AND MOSTLY DRY WEATHER AS
THE UPPER RIDGE WHICH HAD BEEN PUSHED WEST OVER CALIFORNIA BUILDS
BACK EAST. THIS WILL BRING TEMPERATURES BACK TO AND ABOVE NORMALS
FOR MID TO LATE JULY. MODELS THEN SHOW A WEAK SHORTWAVE TROUGH TO
DROP OUT OF THE PACIFIC NORTHWEST FOR TUESDAY AND WEDNESDAY. THIS
WILL BRING COOLER AND WETTER WEATHER FOR THESE DAYS...WITH SHOWERS
MAINLY OVER THE HIGH TERRAIN TUESDAY THEN SPREADING OVER THE
PLAINS WEDNESDAY.
AVIATION...VFR CONDITIONS WILL PERSIST THROUGH TONIGHT. WINDS
WILL TURN LIGHT WEST/NORTHWEST BY 15Z-17Z THIS MORNING AND THEN
MORE NORTHERLY BY AFTERNOON. SOME GUSTS TO 20 KTS POSSIBLE AFTER
18Z. STORM CHANCES WILL BE HIGHER TODAY...PROBABLY ENOUGH TO
WARRANT AT LEAST A TEMPO GROUP FOR GUSTY OUTFLOW WINDS TO 30-40
KTS. MAIN THREAT WOULD BE 21Z-04Z. SLIGHT CHANCE OF A STRONG
ENOUGH STORM MOVING DIRECTLY OVER THE AIRPORT TO REDUCE VSBYS
TO 3-4SM.
HYDROLOGY...PRECIPITABLE WATER VALUES HAVE ALREADY INCREASED TO
AROUND 1.0 INCH ALONG THE FRONT RANGE. SEE THESE VALUES INCREASING
SLIGHTLY THROUGH THE DAY. AS A RESULT...LOCALLY HEAVY RAIN
POSSIBLE WITH ALL STORMS ESPECIALLY SINCE THEY WILL BE SLOW
MOVING. HOWEVER...WARM CLOUD DEPTH IS LIMITED TO JUST A COUPLE
THOUSAND FEET GIVEN HIGH FREEZING LEVELS...AND RELATIVELY DEEP
SUBCLOUD LAYER WILL LIKELY RESULT IN OUTFLOW DOMINATED STORMS.
MAIN THREAT FOR ANY FLOODING CONCERNS WILL BE IN THE FRONT RANGE
BURN SCARS...SO WILL HAVE TO MONITOR THOSE CLOSELY THIS
AFTERNOON/EVENING. THREAT LOW ENOUGH TO PRECLUDE A FLASH FLOOD
WATCH AT THIS TIME...BUT WILL HIGHLIGHT LOCALLY HEAVY RAINFALL IN
HAZARDOUS WEATHER OUTLOOK.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...COOPER
LONG TERM....KRIEDERMAN
AVIATION...COOPER
AREA FORECAST DISCUSSION
NWS TAUNTON MA
721 AM EDT THU JUL 18 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE MIDWEST AND ATLANTIC COAST WILL BRING
CONTINUED HOT AND HUMID WEATHER TO SOUTHERN NEW ENGLAND THROUGH
SATURDAY. ISOLATED TO WIDELY SCATTERED SHOWERS AND THUNDERSTORMS
ARE POSSIBLE TODAY AND FRIDAY. ON SATURDAY AS A STRONG COLD FRONT
APPROACHES FROM THE GREAT LAKES...THERE IS THE GREATER THREAT FOR
STORMS. RELIEF FROM THE HEAT AND HUMIDITY WILL ARRIVE ON SUNDAY
AND LAST THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
730 AM UPDATE...
FEEL THE LATEST RUNS OF THE HRRR AND WRF-ARW ARE PROVIDING SUBTLE
CLUES AS TO THE OUTCOMES LATER TODAY. COUPLING WITH RAP MODEL
OUTPUT...FEEL THE CAP WILL REMAIN STRETCHED ACROSS THE WESTERN AND
SOUTHERN PORTIONS OF THE LOWER NEW ENGLAND STATES INITIALLY...
WEAKENING SLIGHTLY AS A LOW- TO MID-LEVEL WEAK COLD FRONT SWEEPS
THROUGH NORTHERN NEW ENGLAND.
CONSIDERING THIS POINT AND THE ATTENDANT LONGWAVE FLOW PATTERN...
COULD SEE A REPEAT OF LAST NIGHTS THUNDERSTORM OUTCOMES...BUT
SLIGHTLY SOUTH AND WEST. WILL NEED TO WATCH ANY ACTIVITY AND THE
LONGEVITY OF THAT ACTIVITY AS IT PROGRESSES...WHETHER IT TURNS
MORE RIGHT AWAY FROM THE MEAN FLOW AND MORE WITH CORFIDI VECTOR
FLOW TOWARDS THE AXIS OF GREATER THERMAL-MOIST INSTABILITY AXIS.
HAVE UPDATED CHANCE POPS ACCORDINGLY KEEPING THE BULK OF ACTIVITY
NORTH AND EAST OF A LINE FROM ORANGE MASSACHUSETTS TO PROVIDENCE
RHODE ISLAND WHERE BETTER SHEAR RESIDES. ECHO PREVIOUS FORECASTERS
REMARKS BELOW THAT ANY ADDITIONAL ACTIVITY WILL BE ISOLATED TO
WIDELY SCATTERED. MAIN THREAT CONTINUES TO BE HEAVY RAIN...BUT CAN
NOT RULE OUT A POTENTIAL DAMAGING WIND THREAT WITH STORMS.
PREVIOUS DISCUSSION...
WITH THIS WARM START AND AT LEAST SOME SUNSHINE INITIALLY...TEMPS
ARE LIKELY TO BE A COUPLE OF DEGREES WARMER STILL ACROSS THE
REGION. A WEAK WESTERLY COMPONENT TO THE WIND COULD SUPPLY ENOUGH
DOWNSLOPE FOR THE LOWER CT VALLEY TO REACH THE UPPER 90S TO
POSSIBLY EVEN NEAR THE CENTURY MARK. EXPECTING MIXED DWPTS TO
REMAIN IN THE UPPER 60S TO LOW 70S. GIVEN ALL OF THIS...STILL
SEEING 105+ HEAT INDICES ALONG THE NRN CT/RI AND SRN MA...SO NO
CHANGES TO THE CURRENT HEAT HEADLINES. A VERY HOT AND VERY HUMID
DAY IS EXPECTED IN SPITE OF THE REMNANT CLOUD COVER. SEA BREEZES
MAY MOVE IN LATE AS UPPER LVL FLOW WEAKENS SOMEWHAT...SO WARMER
NEAR THE CLOSE UNTIL THE RELIEF ARRIVES.
THE OTHER ISSUE TODAY IS THE POTENTIAL FOR CONVECTION. WITH WARMER
LOW LVL TEMPS AND AND A COLD FRONT JUST UPSTREAM...AM NOTING A BIT
COOLER MID LVL TEMPS AND SLIGHTLY LESS OF A CAP TODAY THAN
PREVIOUS DAYS. ALSO...WITH THE RIDGE BEGINNING TO BREAK DOWN AND
SLIDE E...LOWERING HEIGHTS MAY COMBINE WITH A WEAK REMNANT PRE
FRONTAL TROF AS A TRIGGER FOR DIURNAL CONVECTION. ML CAPE VALUES
SHOULD APPROACH THE 1500-2000J/KG MARK. VERY LITTLE SHEAR SUGGESTS
THAT ANY STORMS THAT FORM WOULD HAVE DIFFICULTY ORGANIZING LEADING
TO THE BIGGEST THREAT BEING HEAVY RAIN...ALTHOUGH THE LATEST
SWODY1 PROBABILISTIC VALUES HAVE MUCH OF THE BOX CWA IN THE 5
PERCENT WIND/HAIL THREATS GIVEN THE AMOUNT OF AVAILABLE CAPE. FEEL
THAT ANY CONVECTION WOULD BE ISOLATED TO WIDELY SCATTERED GIVEN H7
TEMPS ARE STILL NEAR +10C...AND THE BEST FORCING/SHEAR IS
UPSTREAM. IT APPEARS THE HIGHEST LIKELIHOOD FOR A STORM WOULD BE
IF ONE FORMS UPSTREAM THEN RIDES THE HIGHER INSTABILITY GRADIENT
INTO SRN NEW ENGLAND.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
UPPER LVL RIDGE BEINGS MAKING ITS SLIDE TO THE S AND E ALLOWING
RETURN FLOW TO BEGIN TO DOMINATE OVERNIGHT. THIS ALLOWS THE
STALLED FRONT TO THE N TO LIFT AS A WARM FRONT ALLOWING STILL
WARMER AIR INTO THE LOW MID LVLS. THIS PROVIDES YET A BETTER CAP
OVERNIGHT...AND COMBINING THIS WITH THE LOSS OF DIURNAL HEAT...AND
ANY STORMS OR SHOWERS SHOULD DISSIPATE THROUGH ABOUT MIDNIGHT.
WARMER RETURN FLOW AND LEFTOVER CONVECTIVE DEBRIS MAY KEEP MIN
TEMPS WELL INTO THE 70S OVER MUCH OF THE REGION. SOME LATE NIGHT
FOG/STRATUS IS POSSIBLE ALONG THE SOUTH COAST/CAPE/ISLANDS.
FRI...
SW RETURN FLOW THROUGH THE DAY THANKS TO WARM ADVECTION BEHIND A
WARM FRONT LIFTING INTO CANADA. THIS RAISES MID LVL TEMPS FURTHER
STILL WITH THE POSSIBILITY OF H7 TEMPS WARMER THAN +10C BY THE
HEAT OF THE AFTERNOON. COLUMN MOISTURE DOES INCREASE THROUGH THE
DAY THANKS TO THIS FLOW WITH PWAT VALUES AROUND 2.0 INCHES BY THE
LATTER HALF OF THE DAY. THIS ALLOWS CAPE VALUES TO RISE...BUT WITH
A VERY WARM CAPPING INVERSION IN PLACE...IT MAY BE DIFFICULT TO
GET ANY THUNDERSTORMS OR SHOWERS TO FORM WITH LITTLE FORCING
/TOUGHER SETUP FOR SEA BREEZES WITH STRONG RETURN FLOW/. NOT OUT
OF THE QUESTION ANOTHER LEE/WARM AIR TROF FORMS...BUT HAVE LOWER
CONFIDENCE IN STORM DEVELOPMENT UNLESS A STRONGER SOURCE FOR LIFT
IS APPARENT. POPS ARE A BIT LOWER THAN THU BECAUSE OF THIS FACT.
THE THREAT IS NON-ZERO HOWEVER...GIVEN THE HIGH CAPE VALUES AND
STRENGTHENING SW FLOW ALOFT.
ANOTHER ROUND OF HOT AND HUMID CONDITIONS FRI IN SPITE OF THE
POSSIBILITY OF EARLY DAY SCT-BKN CLOUD COVER. WARMING MID LVL
TEMPS MAY BE ENOUGH TO OVERCOME ANY CLOUD COVER AS MIXING STILL
REACHES NEAR H8. THEREFORE...ANOTHER ROUND OF TEMPS IN THE LOW-
UPPER 90S POSSIBLE WITH DWPTS HOLDING IN THE LOW TO MID 70S.
ANOTHER ROUND OF HEAT ADVISORIES AND EXCESSIVE HEAT WARNINGS ARE
POSSIBLE...POSSIBLY EXPANDING TO THE I-495 CORRIDOR AND E AS THE W
COMPONENT TO THE FLOW SHOULD FORCE SEA BREEZES TO REMAIN OFFSHORE.
WILL NEED TO MONITOR FOR FURTHER HEAT HEADLINES.
WINDS PICK UP DURING THE AFTERNOON POSSIBLY REACHING 20-30 MPH IN
SPOTS BY LATE IN THE DAY. THIS MAY HELP THE S COAST GIVEN THE SW
DIRECTION...BUT GIVEN THE WARM ADVECTION ASSOCIATED WITH THIS
FLOW...IT WILL LIKELY PROVIDE LITTLE RELIEF FURTHER INLAND.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
HEADLINES...
* SEVERE WEATHER ANTICIPATED FOR SATURDAY INTO SATURDAY NIGHT
* SHOWERS LINGERING SUNDAY...OTHERWISE TURNING COOL/DRY INTO TUESDAY
* WARMER WITH THUNDERSTORMS WEDNESDAY INTO THE END OF THE WEEK
*/OVERVIEW AND MODEL CONSENSUS...
WILL FOLLOW WITH A NON-NAM COMPROMISE BETWEEN THE GFS AND ECMWF AS
IT IS EASILY DISCERNIBLE AND HPC/WPC HAS EMPHASIZED THAT THE NAM
IS AN OUTLIER AND LAGS OTHER MODELS/ENSEMBLE MEANS CONCERNING THE
COLD FRONT FOR SATURDAY. WILL CONTINUE WITH CONTINUITY CONSIDERING
A BLEND OF ENSEMBLE MEANS WITH DETERMINISTIC FORECAST OUTCOMES
FROM THE GFS/ECMWF THROUGH TUESDAY...FOLLOWING THE ECMWF
THEREAFTER FEELING THERE ARE CONVECTIVE FAILURES WITH THE 18.0Z
GFS.
*/DAY-TO-DAY DETAILS...
*/SATURDAY...
HIGH PRESSURE SHIFTING TOWARDS THE FOUR-CORNERS AS AN AREA OF LOW
PRESSURE AMPLIFIES ACROSS NORTHERN ONTARIO ALLOWS FOR HEIGHT FALLS
OVER THE NORTHEASTERN CONUS. AN ATTENDANT COLD FRONT TO THE LOW IS
THE FOCUS OF LOW- TO MID-LEVEL FRONTOGENESIS COUPLED WITH THE MAIN
MID- TO UPPER-LEVEL IMPULSE AND RIGHT-REAR QUADRANT OF THE UPPER-
LEVEL JET WILL GENERATE AN ENVIRONMENT OF FAVORABLE DEEP-LAYER
ASCENT. CONSIDERING A DESTABILIZING VERY WARM AND MOIST AIRMASS
ALONG AND AHEAD OF THE COLD FRONT...THERE IS THE EXPECTATION FOR A
SUSTAINING LINE OF STRONG TO SEVERE THUNDERSTORMS /ECHOED BY THE SPC
DAY 3 OUTLOOK/.
UNI-DIRECTIONAL WEST-SOUTHWEST SHEAR SUPPORTS AN ENVIRONMENT OF
CONVECTIVE LINE SEGMENTS AND MULTI-CELLULAR THUNDERSTORM CLUSTERS
PRESENTING THE THREAT OF STRONG TO DAMAGING WINDS. IN ADDITION...
WITH THE DEEP-MOIST RICH ATMOSPHERE /PWATS UP TO 2 INCHES/ HEAVY
RAIN IS ANTICIPATED ALONG WITH LOCALIZED FLASH FLOODING. NOT SO
CERTAIN ON THE NEED OF FLOOD WATCH HEADLINES AS BOTH FLOW AND COLD
FRONTAL PASSAGED ARE PROGRESSIVELY MODELED.
CONCERNING INSTABILITY...MID-LEVEL LAPSE RATES ARE MARGINAL. THERE
IS SOME QUESTION AS TO WHETHER THE BOUNDARY LAYER WILL EFFECTIVELY
DESTABILIZE. THERE ARE SUBTLE HINTS OF LIMITATIONS DUE TO CLOUD
DEBRIS...INITIAL ACTIVITY ALONG A PRE-FRONTAL TROUGH...AND/OR A
CAPPING INVERSION AT H85 NEAR +20C. FEEL CONFIDENT THAT THE REGION
WILL REMAIN CAPPED INTO THE AFTERNOON ALLOWING THE WARM-SECTOR TO
DEVELOP AND DESTABILIZE. SHOWERS AND THUNDERSTORMS ALONG WITH
ATTENDANT THREATS WILL INCREASE IN COVERAGE AND REMAIN FOCUSED ALONG
THE COLD FRONT WITH DEEP-LAYER LIFT. HIGH FREEZING LEVELS AND THIN
CAPES SUPPORT THE THREAT FOR SMALL HAIL BELOW SEVERE THUNDERSTORM
THRESHOLDS OF 1 INCH.
GREATEST CONFIDENCE OF AFOREMENTIONED THREATS ACROSS INTERIOR NEW
ENGLAND /ESPECIALLY TO THE WESTERN HALF OF NEW ENGLAND/...WEAKENING
SOUTH AND EAST DURING THE NOCTURNAL PASSAGE GRADUALLY OFFSHORE.
HIGHS INTO THE LOW-90S WITH LOW-70 DEWPOINTS. SOUTHWEST WINDS AHEAD
OF THE FRONT GUSTING AROUND 25 MPH...BACKING OUT OF THE NORTH-
NORTHWEST AND WEAKENING WITH COLD FRONTAL PASSAGE. GFS AND ECMWF
DETERMINISTIC AND ENSEMBLE GUIDANCE SUCCINCT ON THE SURFACE COLD
FRONT OFFSHORE OF NEW ENGLAND BY SUNDAY MORNING.
*/SUNDAY INTO TUESDAY...
COLD FRONT CONTINUES TO DRIFT OUT TO SEA. WILL NEED TO MONITOR WEAK
WAVE DISTURBANCES INVOKING AREAS OF LOW PRESSURE ALONG THE FRONTAL
BOUNDARY WHICH COULD POTENTIALLY SWING WET WEATHER BACK WEST. WILL
KEEP CHANCE TO SLIGHT CHANCE POPS FOR SOUTH-SOUTHEAST NEW ENGLAND ON
SUNDAY.
OTHERWISE...CANADIAN HIGH PRESSURE WILL BUILD ACROSS THE REGION
USHERING COOLER AND SEASONABLE CONDITIONS FOR SOUTHERN NEW ENGLAND
PUTTING AN END TO THE OPPRESSIVE HEAT AND HUMIDITY. WILL KEEP DRY
CONDITIONS THROUGH TUESDAY FEELING THAT RIDGING OF HIGH PRESSURE AS
IT MOVES EAST TOWARDS NEWFOUNDLAND WILL KEEP ANY THUNDERSTORM
ACTIVITY WITH RETURN SOUTHERLY FLOW WEST OF THE FORECAST REGION
ACROSS NEW YORK AND PENNSYLVANIA.
*/WEDNESDAY INTO THE WEEK...
WITH GREATER WEIGHT TOWARDS THE ECMWF...RETURN SOUTHERLY FLOW
COUPLED WITH BROAD TROUGHING BUILDING ACROSS THE REGION WITH
TRAVERSING WEAK WAVE DISTURBANCES SHOULD INVOKE A WEAK AREA OF LOW
PRESSURE ACROSS THE NORTHEASTERN CONUS WITH SUBSEQUENT PERIODS OF
SHOWERS AND THUNDERSTORMS...LIKELY DURING THE DAY WITH BOUNDARY
LAYER DESTABILIZATION.
WILL KEEP CONDITIONS CLOSE TO SEASONABLE LEVELS WITH PREVAILING
SOUTHERLY FLOW AS THE LOW- TO MID-LEVEL LOW PRESSURE TRACKS
NORTHEASTWARD TO THE WEST OF SOUTHERN NEW ENGLAND. CONTINUED LOW
CONFIDENCE OF SEVERE WEATHER THREATS...HEAVY RAIN CERTAINLY PLAUSIBLE.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
MODERATE CONFIDENCE THROUGH FRIDAY...
VFR. HAVE GROWING CONFIDENCE OF SHRA/TSRA NORTH AND EAST OF A LINE
FROM ORE-PVD. VCTS PREVAILED ACCORDINGLY FOR THE LATE AFTERNOON
INTO EARLY EVENING PERIOD. ACTIVITY ELSEWHERE WILL BE ISOLATED TO
WIDELY SCATTERED. LOW-VFR/MVFR CIGS WITH TSRA...WHILE ANY +RA
WILL LIKELY BE ASSOCIATED WITH MVFR/IFR VSBYS. OTHERWISE...SEA-
BREEZES ALONG THE EAST AND SOUTH SHORES AROUND MIDDAY.
PATCHY FOG LATER TONIGHT AND AGAIN FRIDAY NIGHT ESPECIALLY ALONG
THE SOUTH COAST AND ISLANDS WITH AREAS OF IFR-VLIFR CIGS/VSBYS
POSSIBLE.
KBOS TERMINAL...MODERATE CONFIDENCE IN TAF TRENDS. SEA-BREEZE
AROUND MIDDAY. VCTS POSSIBLE IN THE LATE AFTERNOON INTO EARLY
EVENING HOURS.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF. DID NOT PREVAIL VCTS DUE
TO LESSER CONFIDENCE.
OUTLOOK...SATURDAY INTO TUESDAY...
SATURDAY...MODERATE CONFIDENCE.
SHRA/TSRA AHEAD OF A COLD FRONT SWEEPING THROUGH THE TERMINALS LATE
IN THE DAY...OFFSHORE BY SUNDAY MORNING. TSRA MAY BE STRONG TO
SEVERE WITH GUSTY WINDS AND SMALL HAIL...AWW/S POSSIBLE WITH THE
ADDITIONAL THREAT OF LIGHTNING. LOW-VFR/MVFR CIGS WITH TSRA...
MVFR/IFR VSBYS WITH +RA. SOUTHWEST WINDS GUSTING AROUND 25 MPH
BACKING OUT OF THE NORTH-NORTHWEST AND WEAKENING WITH COLD FRONTAL
PASSAGE.
SUNDAY INTO TUESDAY...MODERATE CONFIDENCE.
VFR. LIGHT AND VARIABLE FLOW. SEA-BREEZES POSSIBLE DURING THE MIDDAY
INTO AFTERNOON HOURS SUNDAY AND MONDAY. MAY SEE A RETURN OF
SHRA/TSRA FOR TUESDAY.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
HIGH CONFIDENCE THROUGH TONIGHT...MODERATE CONFIDENCE ON FRIDAY
REGARDING THREAT FOR SMALL CRAFT ADVISORY CONDITIONS...
WINDS AND SEAS REMAIN BELOW SMALL CRAFT ADVISORY LEVEL THRESHOLDS
THROUGH THE OVERNIGHT HOURS TONIGHT ALTHOUGH WINDS WILL GRADUALLY
SHIFT FROM W TO SW DURING THE OVERNIGHT HOURS. SOME MARINE
FOG/STRATUS IS POSSIBLE LATE TONIGHT/EARLY FRI MORNING
PARTICULARLY ON SRN WATERS.
INCREASING SW FLOW MAY ALLOW WINDS TO REACH NEAR 25 KT
PARTICULARLY ALONG THE NEAR SHORE WATERS NEAR THE SOUTH COAST
CAPE/ISLANDS. THE INCREASING FLOW MAY ALSO ALLOW SEAS TO REACH 5+
FT BY THE LATE DAY EARLY FRI NIGHT TIMEFRAME ON PARTICULARLY ON
THE SRN AND SERN OCEAN WATERS. SMALL CRAFT ADVISORIES MAY BE
NECESSARY.
OUTLOOK...SATURDAY INTO TUESDAY...
SATURDAY INTO SUNDAY...MODERATE CONFIDENCE.
SHOWERS AND THUNDERSTORMS AHEAD OF A COLD FRONT SWEEPING INTO THE
WATERS AROUND MIDNIGHT SUNDAY...EXITING WELL OUT TO SEA LATE SUNDAY.
THUNDERSTORMS MAY BE STRONG TO SEVERE WITH FREQUENT LIGHTNING...GALE
FORCE WINDS...AND HEAVY RAIN /RESULTING IN VISIBILITY RESTRICTIONS/.
WILL SEE SOUTHWEST GUSTS AROUND 25 KTS PRIOR TO FRONTAL PASSAGE
/SEAS BUILDING TO AROUND 6 FEET OVER THE SOUTH-SOUTHEAST WATERS/...
BACKING OUT OF THE NORTH-NORTHEAST AND WEAKENING /ALLOWING SEAS TO
RELAX/. SMALL CRAFT ADVISORIES LIKELY.
MONDAY INTO TUESDAY...MODERATE CONFIDENCE.
HIGH PRESSURE IN CONTROL ALLOWING FOR LIGHT AND VARIABLE FLOW. WINDS
WILL BEGIN TO TURN MORE SOUTHERLY INTO TUESDAY AS THE HIGH SHIFTS
EAST. LOW CONFIDENCE CONCERNING SHOWERS AND THUNDERSTORMS ALONG THE
NEAR-SHORE WATERS FOR LATE TUESDAY.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...EXCESSIVE HEAT WARNING FROM 11 AM THIS MORNING TO 7 PM EDT
THIS EVENING FOR CTZ002>004.
MA...AIR QUALITY ALERT FROM 11 AM THIS MORNING TO 11 PM EDT THIS
EVENING FOR MAZ020>024.
HEAT ADVISORY FROM 11 AM THIS MORNING TO 7 PM EDT THIS EVENING
FOR MAZ003>007-010>012-014>016-019-026.
EXCESSIVE HEAT WARNING FROM 11 AM THIS MORNING TO 7 PM EDT
THIS EVENING FOR MAZ013-017-018-020-021.
NH...HEAT ADVISORY FROM 11 AM THIS MORNING TO 7 PM EDT THIS EVENING
FOR NHZ012.
RI...AIR QUALITY ALERT FROM 11 AM THIS MORNING TO 11 PM EDT THIS
EVENING FOR RIZ003>008.
HEAT ADVISORY FROM 11 AM THIS MORNING TO 7 PM EDT THIS EVENING
FOR RIZ005-007.
EXCESSIVE HEAT WARNING FROM 11 AM THIS MORNING TO 7 PM EDT
THIS EVENING FOR RIZ001>004-006.
MARINE...NONE.
&&
$$
SYNOPSIS...DOODY/SIPPRELL
NEAR TERM...DOODY/SIPPRELL
SHORT TERM...DOODY
LONG TERM...SIPPRELL
AVIATION...DOODY/SIPPRELL
MARINE...DOODY/SIPPRELL
AREA FORECAST DISCUSSION
NWS MIAMI FL
210 PM EDT THU JUL 18 2013
.AVIATION...
MAIN CONVECTION OVER EASTERN PORTIONS OF PENINSULA HAS NOW
DIMINISHED AS ATMOSPHERE HAS AT LEAST TEMPORARILY STABILIZED AS
LOW LEVELS HAVE BECOME RAIN COOLED. FOR WESTERN
AREAS...THUNDERSTORM COMPLEX FROM THE GULF HAS INTRUDED INTO
COASTAL AREAS AND APPEARS ON TRACK TO IMPACT MOST OF WESTERN HALF
OF SOUTH FLORIDA THROUGH LATE THIS AFTERNOON. TAFS REFLECT THE
ABOVE THINKING...WITH VCSH FOR ALL EASTERN TERMINALS...AND VCTS
WITH TEMPO TSRA FOR KAPF...ALL THROUGH 0Z.
THEREAFTER...PRECIPITATION SHOULD DIURNALLY WANE. FOR
FRIDAY...RIBBON OF DRIER AIR/SUBSIDENCE SHOULD CROSS SOUTH
FLORIDA...THUS SHWR CHANCES ARE AROUND 30 PERCENT OR SO...AND DONT
WARRANT MENTION IN TAFS. VFR CONDITIONS SHOULD BE MOST
PREVALENT...BUT PERIODS OF SIGNIFICANT RESTRICTIONS WILL ACCOMPANY
THUNDERSTORMS. WHERE COVERAGE IS MOST WIDESPREAD...KAPF...TEMPO
MVFR CONDITIONS HAVE BEEN INTRODUCED.
WINDS WILL BE SOUTHEAST AROUND 10-15 KTS TODAY AND FRIDAY...BUT
AROUND 5 KTS OVERNIGHT. MUCH GUSTIER WINDS OUT OF VARIABLE
DIRECTIONS CAN BE EXPECTED AROUND STRONGER CONVECTION.
&&
.PREV DISCUSSION... /ISSUED 1058 AM EDT THU JUL 18 2013/
UPDATE...
LARGE SCALE CONVECTION CONVECTION CONTINUES ACROSS THE EASTERN
GULF...ACROSS THE FLORIDA STRAITS AND EASTWARD INTO THE BAHAMAS.
LOCALLY...HEAVY SHOWERS AND THUNDERSTORMS CONTINUE ACROSS THE
LOCAL GULF WATERS...BISCAYNE BAY AND PORTIONS OF THE EAST COAST
METRO AREAS AND THE ADJACENT ATLANTIC WATERS. THE 12Z SOUNDING INDICATED
DEEP TROPICAL MOISTURE CONTINUING ACROSS THE REGION WITH A PWAT
NEAR 2.2 INCHES.
THE SHORT TERM FORECAST FOR THE LATE MORNING AND AFTERNOON WAS
UPDATED TO REFLECT THE INCREASED COVERAGE OF SHOWERS AND
THUNDERSTORMS ACROSS THE REGION...BOTH INDICATED BY LOCAL
OBSERVATIONS AND RECENT MESO-SCALE MODEL GUIDANCE. RECENT RADAR
RETURNS AND SATELLITE IMAGERY INDICATE ON-GOING CONVECTION ACROSS
THE FLORIDA STRAITS LIFTING NORTHWARD. THIS IS REFLECTED IN THE
MESO-SCALE GUIDANCE AS WELL. IN ADDITION THE MESO-SCALE GUIDANCE
INDICATES WIDESPREAD SHOWERS ACROSS THE PENINSULA STARTING AROUND
16Z WITH STORMS FORECAST TO LIFT NORTHWARD. TO SUM UP...THE
FORECAST FOR THE LATE MORNING THROUGH THE AFTERNOON IS FOR INCREASING
COVERAGE OF SHOWERS AND THUNDERSTORMS WITH A GENERAL NORTHWARD
MOTION OF THE STORMS. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE IN
ISOLATED AREAS.
60
PREV DISCUSSION... /ISSUED 728 AM EDT THU JUL 18 2013/
AVIATION...
CHALLENGING TAF FORECAST. GLOBAL MODELS SHOW AN ACTIVE DAY AREA
WIDE, WHILE THE HRRR ONLY SHOWS IT BECOMING ACTIVE TOWARDS THE GULF
COAST...SO LESS CONFIDENCE ON TSTORMS EAST COAST SITES. HAVE A MORNING
TEMPO OF MVFR SHRA/VCTS EAST COAST SITES. FOR KAPF, HAVE AN AFTERNOON
TEMPO OF TSRA/MVFR. HOWEVER, IFR COULD OCCUR AT ANY GIVEN TERMINAL
SHOULD HEAVY SHOWERS OR TSTORMS IMPACT THOSE AREA, BUT CONFIDENCE
IS TOO LOW TO INCLUDE IN THE TAFS AT THIS TIME. LIGHT-CALM WINDS
EARLY THIS MORNING WILL BECOME SE AT 5-10 KT EAST COAST AND S-SE
5-10 KT AT KAPF.
GREGORIA
PREV DISCUSSION... /ISSUED 330 AM EDT THU JUL 18 2013/
DISCUSSION...
AN UPPER LEVEL LOW REMAINS ACROSS THE EASTERN GULF...AND A LOW
LEVEL/SURFACE TROUGH BISECTS THE REGION EARLY THIS MORNING. THE
UPPER LEVEL LOW WILL BEGIN TO SHIFT TO THE NORTHWEST...AND THE LOW
LEVEL TROUGH WILL ALSO LIFT NORTHWESTWARD INTO CENTRAL FLORIDA
DURING THE DAY TODAY. THE FOCUS FOR SHOWERS THIS MORNING SHOULD BE
ACROSS EXTREME NORTHEAST BROWARD AND ACROSS EASTERN PALM BEACH
COUNTY ALONG AND AHEAD OF THE TROUGH AXIS. OTHER SCATTERED LIGHT
SHOWERS WERE MOVING NORTHWARD OVER THE FLORIDA STRAITS AND FLORIDA
KEYS AND INTO DEEP SOUTH FLORIDA.
PWATS WILL REMAIN ABOVE 2 INCHES TODAY. THE STEERING FLOW IS
FORECAST TO BECOME WEAK OUT OF THE SOUTHWEST BY THIS AFTERNOON. SO
OVERALL STORM MOTION WILL BE VERY SLOW. GLOBAL AND HIGH RES MODEL
GUIDANCE IS NOT TOO BULLISH ON HEAVY RAINFALL FOR THE EAST COAST
METRO AREAS PAST EARLY THIS MORNING AS THE FOCUSING MECHANISM
SHIFTS OUT OF THE REGION. HOWEVER...WITH SO MUCH RAIN FALLING OVER
THE PAST SEVERAL DAYS...IT WILL NOT TAKE MUCH TO CREATE MORE
FLOODING. SO A SLIGHT FLOOD RISK WILL REMAIN IN THE HWO FOR THE
ENTIRE REGION. WITH A LITTLE MORE DAYTIME HEATING EXPECTED THIS
AFTERNOON...WEAK SEA BREEZE BOUNDARIES MAY DEVELOP. SHOWERS AND
STORMS WOULD THEN LIKELY FOCUS ACROSS THE NORTHERN INTERIOR AND
TOWARDS THE GULF COAST...WHERE THE DEEPER MOISTURE WILL RESIDE.
THE SUBTROPICAL RIDGE WILL BEGIN TO BUILD IN FROM THE WEST TONIGHT
AND INTO FRIDAY. SOMEWHAT DRIER AIR WILL PUSH NORTHWEST ACROSS
THE REGION BEHIND THE LOW LEVEL TROUGH AND AHEAD OF A TROPICAL
WAVE. SO RAIN CHANCES WILL BE MUCH LOWER...ESPECIALLY SOUTHEAST.
A TROPICAL WAVE CURRENTLY NEAR PUERTO RICO WILL MOVE WEST AND ACROSS
SOUTH FLORIDA ON SATURDAY...WITH PWATS PROJECTED TO INCREASE TO
2.1-2.3 INCHES. SO NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS ARE
FORECAST FOR SOUTH FLORIDA AS THE WAVE MOVES THROUGH. THE
SUBTROPICAL RIDGE WILL THEN CONTINUE TO BUILD INTO THE REGION SUNDAY
THROUGH THE MIDDLE OF NEXT WEEK. DRIER AIR IS ALSO FORECAST TO PUSH
INTO THE REGION...AND RAINFALL CHANCES ARE FORECAST TO BE BELOW
NORMAL THROUGH THE MIDDLE OF THE WEEK. TEMPERATURES WILL SLOWLY WARM
INTO THE LOW 90S FOR THE COASTAL AREAS AND LOW/MID 90S INTERIOR.
WITH DEWPOINTS IN THE MID 70S...HEAT INDICES ARE FORECAST TO BE IN
THE UPPER 90S TO AROUND 100 FOR THE COASTAL AREAS AND 100-105
DEGREES ACROSS THE INTERIOR.
AVIATION...06Z TAFS.
AN AREA OF SHOWERS AND A FEW THUNDERSTORMS WILL
CONTINUE JUST NE OF KFXE NEXT HOUR OR SO BEFORE MOVING NORTH
TOWARDS KPBI, SO ADDED VCTS FOR KFXE NEXT 2 HR WITH THEN A TEMPO
OF TSRA/MVFR FOR KPBI FROM 08-10Z. OTHERWISE, VFR WILL PREVAIL
ACROSS THE AREA. HOWEVER, ADDITIONAL ACTIVITY IS EXPECTED TO
DEVELOP ESPECIALLY AFTER SUNRISE SO KEPT WITH VCTS. LIGHT WINDS
THIS MORNING WILL BECOME SE 5-10 KT THIS AFTERNOON, EXCEPT S AT
KAPF. /GREGORIA
MARINE...
A WEAK SURFACE TROUGH WILL CONTINUE TO LIFT NORTHWESTWARD ACROSS
THE REGION THIS MORNING...AND THE PRESSURE GRADIENT AND REGIONAL
WINDS ARE FORECAST TO SLOWLY SUBSIDE WITH THE GULF AND ATLANTIC
SEAS FORECAST TO SLOWLY SUBSIDE TODAY. OTHERWISE...WINDS AND SEAS
ARE EXPECTED TO REMAIN WELL BELOW ADVISORY LEVELS THROUGH THE
FORECAST PERIOD.
FIRE WEATHER...
LIGHT EAST TO SOUTHEAST FLOW AND MOIST CONDITIONS THROUGH THE
PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 75 87 78 87 / 40 30 30 50
FORT LAUDERDALE 77 88 78 88 / 40 30 40 50
MIAMI 76 88 78 88 / 50 30 40 50
NAPLES 74 91 76 89 / 50 40 30 50
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...60/BD
AVIATION/RADAR...59/RM
AREA FORECAST DISCUSSION
NWS MIAMI FL
1058 AM EDT THU JUL 18 2013
.UPDATE...
LARGE SCALE CONVECTION CONVECTION CONTINUES ACROSS THE EASTERN
GULF...ACROSS THE FLORIDA STRAITS AND EASTWARD INTO THE BAHAMAS.
LOCALLY...HEAVY SHOWERS AND THUNDERSTORMS CONTINUE ACROSS THE
LOCAL GULF WATERS...BISCAYNE BAY AND PORTIONS OF THE EAST COAST
METRO AREAS AND THE ADJACENT ATLANTIC WATERS. THE 12Z SOUNDING INDICATED
DEEP TROPICAL MOISTURE CONTINUING ACROSS THE REGION WITH A PWAT
NEAR 2.2 INCHES.
THE SHORT TERM FORECAST FOR THE LATE MORNING AND AFTERNOON WAS
UPDATED TO REFLECT THE INCREASED COVERAGE OF SHOWERS AND
THUNDERSTORMS ACROSS THE REGION...BOTH INDICATED BY LOCAL
OBSERVATIONS AND RECENT MESO-SCALE MODEL GUIDANCE. RECENT RADAR
RETURNS AND SATELLITE IMAGERY INDICATE ON-GOING CONVECTION ACROSS
THE FLORIDA STRAITS LIFTING NORTHWARD. THIS IS REFLECTED IN THE
MESO-SCALE GUIDANCE AS WELL. IN ADDITION THE MESO-SCALE GUIDANCE
INDICATES WIDESPREAD SHOWERS ACROSS THE PENINSULA STARTING AROUND
16Z WITH STORMS FORECAST TO LIFT NORTHWARD. TO SUM UP...THE
FORECAST FOR THE LATE MORNING THROUGH THE AFTERNOON IS FOR INCREASING
COVERAGE OF SHOWERS AND THUNDERSTORMS WITH A GENERAL NORTHWARD
MOTION OF THE STORMS. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE IN
ISOLATED AREAS.
60
&&
.PREV DISCUSSION... /ISSUED 728 AM EDT THU JUL 18 2013/
AVIATION...
CHALLENGING TAF FORECAST. GLOBAL MODELS SHOW AN ACTIVE DAY AREA
WIDE, WHILE THE HRRR ONLY SHOWS IT BECOMING ACTIVE TOWARDS THE GULF
COAST...SO LESS CONFIDENCE ON TSTORMS EAST COAST SITES. HAVE A MORNING
TEMPO OF MVFR SHRA/VCTS EAST COAST SITES. FOR KAPF, HAVE AN AFTERNOON
TEMPO OF TSRA/MVFR. HOWEVER, IFR COULD OCCUR AT ANY GIVEN TERMINAL
SHOULD HEAVY SHOWERS OR TSTORMS IMPACT THOSE AREA, BUT CONFIDENCE
IS TOO LOW TO INCLUDE IN THE TAFS AT THIS TIME. LIGHT-CALM WINDS
EARLY THIS MORNING WILL BECOME SE AT 5-10 KT EAST COAST AND S-SE
5-10 KT AT KAPF.
GREGORIA
PREV DISCUSSION... /ISSUED 330 AM EDT THU JUL 18 2013/
DISCUSSION...
AN UPPER LEVEL LOW REMAINS ACROSS THE EASTERN GULF...AND A LOW
LEVEL/SURFACE TROUGH BISECTS THE REGION EARLY THIS MORNING. THE
UPPER LEVEL LOW WILL BEGIN TO SHIFT TO THE NORTHWEST...AND THE LOW
LEVEL TROUGH WILL ALSO LIFT NORTHWESTWARD INTO CENTRAL FLORIDA
DURING THE DAY TODAY. THE FOCUS FOR SHOWERS THIS MORNING SHOULD BE
ACROSS EXTREME NORTHEAST BROWARD AND ACROSS EASTERN PALM BEACH
COUNTY ALONG AND AHEAD OF THE TROUGH AXIS. OTHER SCATTERED LIGHT
SHOWERS WERE MOVING NORTHWARD OVER THE FLORIDA STRAITS AND FLORIDA
KEYS AND INTO DEEP SOUTH FLORIDA.
PWATS WILL REMAIN ABOVE 2 INCHES TODAY. THE STEERING FLOW IS
FORECAST TO BECOME WEAK OUT OF THE SOUTHWEST BY THIS AFTERNOON. SO
OVERALL STORM MOTION WILL BE VERY SLOW. GLOBAL AND HIGH RES MODEL
GUIDANCE IS NOT TOO BULLISH ON HEAVY RAINFALL FOR THE EAST COAST
METRO AREAS PAST EARLY THIS MORNING AS THE FOCUSING MECHANISM
SHIFTS OUT OF THE REGION. HOWEVER...WITH SO MUCH RAIN FALLING OVER
THE PAST SEVERAL DAYS...IT WILL NOT TAKE MUCH TO CREATE MORE
FLOODING. SO A SLIGHT FLOOD RISK WILL REMAIN IN THE HWO FOR THE
ENTIRE REGION. WITH A LITTLE MORE DAYTIME HEATING EXPECTED THIS
AFTERNOON...WEAK SEA BREEZE BOUNDARIES MAY DEVELOP. SHOWERS AND
STORMS WOULD THEN LIKELY FOCUS ACROSS THE NORTHERN INTERIOR AND
TOWARDS THE GULF COAST...WHERE THE DEEPER MOISTURE WILL RESIDE.
THE SUBTROPICAL RIDGE WILL BEGIN TO BUILD IN FROM THE WEST TONIGHT
AND INTO FRIDAY. SOMEWHAT DRIER AIR WILL PUSH NORTHWEST ACROSS
THE REGION BEHIND THE LOW LEVEL TROUGH AND AHEAD OF A TROPICAL
WAVE. SO RAIN CHANCES WILL BE MUCH LOWER...ESPECIALLY SOUTHEAST.
A TROPICAL WAVE CURRENTLY NEAR PUERTO RICO WILL MOVE WEST AND ACROSS
SOUTH FLORIDA ON SATURDAY...WITH PWATS PROJECTED TO INCREASE TO
2.1-2.3 INCHES. SO NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS ARE
FORECAST FOR SOUTH FLORIDA AS THE WAVE MOVES THROUGH. THE
SUBTROPICAL RIDGE WILL THEN CONTINUE TO BUILD INTO THE REGION SUNDAY
THROUGH THE MIDDLE OF NEXT WEEK. DRIER AIR IS ALSO FORECAST TO PUSH
INTO THE REGION...AND RAINFALL CHANCES ARE FORECAST TO BE BELOW
NORMAL THROUGH THE MIDDLE OF THE WEEK. TEMPERATURES WILL SLOWLY WARM
INTO THE LOW 90S FOR THE COASTAL AREAS AND LOW/MID 90S INTERIOR.
WITH DEWPOINTS IN THE MID 70S...HEAT INDICES ARE FORECAST TO BE IN
THE UPPER 90S TO AROUND 100 FOR THE COASTAL AREAS AND 100-105
DEGREES ACROSS THE INTERIOR.
AVIATION...06Z TAFS.
AN AREA OF SHOWERS AND A FEW THUNDERSTORMS WILL
CONTINUE JUST NE OF KFXE NEXT HOUR OR SO BEFORE MOVING NORTH
TOWARDS KPBI, SO ADDED VCTS FOR KFXE NEXT 2 HR WITH THEN A TEMPO
OF TSRA/MVFR FOR KPBI FROM 08-10Z. OTHERWISE, VFR WILL PREVAIL
ACROSS THE AREA. HOWEVER, ADDITIONAL ACTIVITY IS EXPECTED TO
DEVELOP ESPECIALLY AFTER SUNRISE SO KEPT WITH VCTS. LIGHT WINDS
THIS MORNING WILL BECOME SE 5-10 KT THIS AFTERNOON, EXCEPT S AT
KAPF. /GREGORIA
MARINE...
A WEAK SURFACE TROUGH WILL CONTINUE TO LIFT NORTHWESTWARD ACROSS
THE REGION THIS MORNING...AND THE PRESSURE GRADIENT AND REGIONAL
WINDS ARE FORECAST TO SLOWLY SUBSIDE WITH THE GULF AND ATLANTIC
SEAS FORECAST TO SLOWLY SUBSIDE TODAY. OTHERWISE...WINDS AND SEAS
ARE EXPECTED TO REMAIN WELL BELOW ADVISORY LEVELS THROUGH THE
FORECAST PERIOD.
FIRE WEATHER...
LIGHT EAST TO SOUTHEAST FLOW AND MOIST CONDITIONS THROUGH THE
PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 85 75 87 78 / 60 30 30 30
FORT LAUDERDALE 86 77 88 78 / 70 30 20 40
MIAMI 87 76 88 78 / 70 30 20 40
NAPLES 88 74 91 76 / 60 40 30 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...60/BD
AVIATION/RADAR...59/RM
AREA FORECAST DISCUSSION
NWS MIAMI FL
728 AM EDT THU JUL 18 2013
.AVIATION...
CHALLENGING TAF FORECAST. GLOBAL MODELS SHOW AN ACTIVE DAY AREA
WIDE, WHILE THE HRRR ONLY SHOWS IT BECOMING ACTIVE TOWARDS THE GULF
COAST...SO LESS CONFIDENCE ON TSTORMS EAST COAST SITES. HAVE A MORNING
TEMPO OF MVFR SHRA/VCTS EAST COAST SITES. FOR KAPF, HAVE AN AFTERNOON
TEMPO OF TSRA/MVFR. HOWEVER, IFR COULD OCCUR AT ANY GIVEN TERMINAL
SHOULD HEAVY SHOWERS OR TSTORMS IMPACT THOSE AREA, BUT CONFIDENCE
IS TOO LOW TO INCLUDE IN THE TAFS AT THIS TIME. LIGHT-CALM WINDS
EARLY THIS MORNING WILL BECOME SE AT 5-10 KT EAST COAST AND S-SE
5-10 KT AT KAPF.
GREGORIA
&&
.PREV DISCUSSION... /ISSUED 330 AM EDT THU JUL 18 2013/
DISCUSSION...
AN UPPER LEVEL LOW REMAINS ACROSS THE EASTERN GULF...AND A LOW
LEVEL/SURFACE TROUGH BISECTS THE REGION EARLY THIS MORNING. THE
UPPER LEVEL LOW WILL BEGIN TO SHIFT TO THE NORTHWEST...AND THE LOW
LEVEL TROUGH WILL ALSO LIFT NORTHWESTWARD INTO CENTRAL FLORIDA
DURING THE DAY TODAY. THE FOCUS FOR SHOWERS THIS MORNING SHOULD BE
ACROSS EXTREME NORTHEAST BROWARD AND ACROSS EASTERN PALM BEACH
COUNTY ALONG AND AHEAD OF THE TROUGH AXIS. OTHER SCATTERED LIGHT
SHOWERS WERE MOVING NORTHWARD OVER THE FLORIDA STRAITS AND FLORIDA
KEYS AND INTO DEEP SOUTH FLORIDA.
PWATS WILL REMAIN ABOVE 2 INCHES TODAY. THE STEERING FLOW IS
FORECAST TO BECOME WEAK OUT OF THE SOUTHWEST BY THIS AFTERNOON. SO
OVERALL STORM MOTION WILL BE VERY SLOW. GLOBAL AND HIGH RES MODEL
GUIDANCE IS NOT TOO BULLISH ON HEAVY RAINFALL FOR THE EAST COAST
METRO AREAS PAST EARLY THIS MORNING AS THE FOCUSING MECHANISM
SHIFTS OUT OF THE REGION. HOWEVER...WITH SO MUCH RAIN FALLING OVER
THE PAST SEVERAL DAYS...IT WILL NOT TAKE MUCH TO CREATE MORE
FLOODING. SO A SLIGHT FLOOD RISK WILL REMAIN IN THE HWO FOR THE
ENTIRE REGION. WITH A LITTLE MORE DAYTIME HEATING EXPECTED THIS
AFTERNOON...WEAK SEA BREEZE BOUNDARIES MAY DEVELOP. SHOWERS AND
STORMS WOULD THEN LIKELY FOCUS ACROSS THE NORTHERN INTERIOR AND
TOWARDS THE GULF COAST...WHERE THE DEEPER MOISTURE WILL RESIDE.
THE SUBTROPICAL RIDGE WILL BEGIN TO BUILD IN FROM THE WEST TONIGHT
AND INTO FRIDAY. SOMEWHAT DRIER AIR WILL PUSH NORTHWEST ACROSS
THE REGION BEHIND THE LOW LEVEL TROUGH AND AHEAD OF A TROPICAL
WAVE. SO RAIN CHANCES WILL BE MUCH LOWER...ESPECIALLY SOUTHEAST.
A TROPICAL WAVE CURRENTLY NEAR PUERTO RICO WILL MOVE WEST AND ACROSS
SOUTH FLORIDA ON SATURDAY...WITH PWATS PROJECTED TO INCREASE TO
2.1-2.3 INCHES. SO NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS ARE
FORECAST FOR SOUTH FLORIDA AS THE WAVE MOVES THROUGH. THE
SUBTROPICAL RIDGE WILL THEN CONTINUE TO BUILD INTO THE REGION SUNDAY
THROUGH THE MIDDLE OF NEXT WEEK. DRIER AIR IS ALSO FORECAST TO PUSH
INTO THE REGION...AND RAINFALL CHANCES ARE FORECAST TO BE BELOW
NORMAL THROUGH THE MIDDLE OF THE WEEK. TEMPERATURES WILL SLOWLY WARM
INTO THE LOW 90S FOR THE COASTAL AREAS AND LOW/MID 90S INTERIOR.
WITH DEWPOINTS IN THE MID 70S...HEAT INDICES ARE FORECAST TO BE IN
THE UPPER 90S TO AROUND 100 FOR THE COASTAL AREAS AND 100-105
DEGREES ACROSS THE INTERIOR.
AVIATION...06Z TAFS.
AN AREA OF SHOWERS AND A FEW THUNDERSTORMS WILL
CONTINUE JUST NE OF KFXE NEXT HOUR OR SO BEFORE MOVING NORTH
TOWARDS KPBI, SO ADDED VCTS FOR KFXE NEXT 2 HR WITH THEN A TEMPO
OF TSRA/MVFR FOR KPBI FROM 08-10Z. OTHERWISE, VFR WILL PREVAIL
ACROSS THE AREA. HOWEVER, ADDITIONAL ACTIVITY IS EXPECTED TO
DEVELOP ESPECIALLY AFTER SUNRISE SO KEPT WITH VCTS. LIGHT WINDS
THIS MORNING WILL BECOME SE 5-10 KT THIS AFTERNOON, EXCEPT S AT
KAPF. /GREGORIA
MARINE...
A WEAK SURFACE TROUGH WILL CONTINUE TO LIFT NORTHWESTWARD ACROSS
THE REGION THIS MORNING...AND THE PRESSURE GRADIENT AND REGIONAL
WINDS ARE FORECAST TO SLOWLY SUBSIDE WITH THE GULF AND ATLANTIC
SEAS FORECAST TO SLOWLY SUBSIDE TODAY. OTHERWISE...WINDS AND SEAS
ARE EXPECTED TO REMAIN WELL BELOW ADVISORY LEVELS THROUGH THE
FORECAST PERIOD.
FIRE WEATHER...
LIGHT EAST TO SOUTHEAST FLOW AND MOIST CONDITIONS THROUGH THE
PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 85 75 87 78 / 70 30 30 30
FORT LAUDERDALE 86 77 88 78 / 60 30 20 40
MIAMI 87 76 88 78 / 50 30 20 40
NAPLES 88 74 91 76 / 60 40 30 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
239 PM EDT THU JUL 18 2013
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 346 AM EDT THU JUL 18 2013
HOT AND HUMID WEATHER WILL CONTINUE THROUGH FRIDAY AS THE RIDGE
ALOFT GRADUALLY SHIFTS TO THE SOUTH. A VIGOROUS UPPER LEVEL LOW WILL
TRACK THROUGH EASTERN CANADA WITH A COLD FRONT TRACKING SOUTH INTO
THE REGION ON SATURDAY. THE ARRIVAL AND PASSAGE OF THE FRONT WILL
BRING NUMEROUS SHOWERS AND THUNDERSTORMS TO CENTRAL INDIANA LATE
FRIDAY NIGHT THROUGH SATURDAY EVENING. COOLER DRIER AIR WILL BRIEFLY
BUILD INTO THE REGION ON SUNDAY AS HIGH PRESSURE PASSES THROUGH THE
GREAT LAKES. CHANCES FOR THUNDERSTORMS WILL RETURN BY LATE SUNDAY
NIGHT AND MONDAY AND CONTINUE THROUGH THE MIDDLE OF NEXT WEEK AS THE
FRONTAL BOUNDARY DRIFTS BACK NORTH INTO THE AREA.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1042 AM EDT THU JUL 18 2013
FEW IF ANY CHANGES NEEDED AT THIS TIME. FORECAST APPEARS TO BE IN
GOOD SHAPE. PREVIOUS DISCUSSION FOLLOWS...
ANOTHER MUGGY START EARLY THIS MORNING AS 07Z TEMPS GENERALLY IN THE
MID AND UPPER 70S. CONVECTIVE DEBRIS CLOUDS CONTINUE TO DRIFT INTO
THE SOUTHERN HALF OF THE FORECAST AREA AS A WEAK UPPER WAVE
CURRENTLY TRACKS ACROSS THE TENNESSEE VALLEY.
THE UPPER LEVEL HIGH REMAINS PARKED ACROSS CENTRAL INDIANA WITH MID
LEVEL HEIGHT MAXES STILL AROUND 597DAM. THESE HEIGHTS WILL SLOWLY
FALL THROUGH THE DAY AS THE RIDGE GRADUALLY BUCKLES IN RESPONSE TO A
DEVELOPING STRONG UPPER LOW GETTING ITS ACT TOGETHER ACROSS JAMES
BAY. THE AFOREMENTIONED WEAK WAVE ALOFT OVER THE TENNESSEE VALLEY
WILL DRIFT WEST THROUGH THE DAY AND SHOULD BE LOCATED OVER THE LOWER
OHIO VALLEY BY LATE DAY. SCATTERED CONVECTION ASSOCIATED WITH THIS
FEATURE SHOULD DEVELOP ACROSS KENTUCKY AND TENNESSEE AND MAY EVEN
SEE A FEW STORMS MAKE IT INTO OUR SOUTHERN COUNTIES. THE HRRR LOOKS
TO BE OVERDOING CONVECTIVE DEVELOPMENT IN GENERAL BUT HINTS AT THIS
IDEA AS WELL. CONSIDERING THE NATURE OF THE AIRMASS AND THE
PROXIMITY OF THE UPPER WAVE...ISOLATED POPS ARE WARRANTED ACROSS FAR
SOUTHERN COUNTIES FOR THIS AFTERNOON. FURTHER NORTH DESPITE THE
GRADUALLY LOWERING MID LEVEL HEIGHTS...THE RIDGING ALOFT AND CAP
NEAR 650MB ARE LIKELY TO REMAIN TOO STRONG FOR ANY SUBSTANTIAL
CONVECTIVE DEVELOPMENT. WHILE AN ISOLATED SHOWER CANNOT BE RULED
OUT...COVERAGE LIKELY TO BE SO LOW TO PRECLUDE ANY MENTION IN THE
FORECAST AT THIS TIME.
TEMPS...LOW LEVEL THERMALS WILL BE SIMILAR TO WEDNESDAY WITH 850MB
TEMPS RISING TO AROUND 19-20C. LIKEWISE EXPECT HIGH TEMPS TO BE
SIMILAR TO WEDNESDAY AS WELL...REACHING THE 92-94 DEGREE RANGE FOR
MUCH OF THE FORECAST AREA. GENERALLY GOING A DEGREE OR TWO ABOVE
MOS. MAX HEAT INDICES WILL RISE TO AROUND 100 DEGREES AGAIN THIS
AFTERNOON...AND MAY TOP OUT JUST A TOUCH WARMER THAN WEDNESDAY AS
SLIGHTLY DEEPER MOISTURE IS PULLED NORTH INTO THE REGION. HAVE NO
PLANS TO INTRODUCE A HEAT ADVISORY AS THESE VALUES REMAINS BELOW
CRITERIA. WILL CONTINUE WITH THE SPS.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 346 AM EDT THU JUL 18 2013
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES AND TEMPS AS A COLD
FRONT DROPS SOUTH THROUGH THE REGION SATURDAY. MODELS GENERALLY IN
VERY GOOD AGREEMENT ON MAIN FEATURES THROUGHOUT THE SHORT TERM.
RIDGING ALOFT WILL CONTINUE TO SINK SOUTH AND FLATTEN AS THE DEEP
UPPER LOW DIVES ACROSS NORTHERN ONTARIO...THEN PINWHEELS INTO THE
CANADIAN MARITIMES BY SUNDAY MORNING. ROBUST CONVECTIVE DEVELOPMENT
WILL TAKE PLACE TONIGHT OVER THE UPPER MISSISSIPPI VALLEY AND
NORTHERN GREAT LAKES IN PROXIMITY TO THE COLD FRONT. THIS FRONT WILL
SINK SOUTH AND SHOULD BE LOCATED ACROSS THE WESTERN GREAT LAKES BY
FRIDAY AFTERNOON. THE FLATTENING OF THE RIDGE AND APPROACH OF THE
COLD FRONT WILL ENCOURAGE A W/SW FLOW THROUGH THE LOWER LEVELS ON
FRIDAY...WITH POTENTIAL FOR SOME GUSTS TO NEAR 20-25KTS OVER
NORTHERN COUNTIES BY AFTERNOON AS A LOW LEVEL JET ACCOMPANIES THE
BOUNDARY THROUGH THE GREAT LAKES. WILL MAINTAIN LOW CHANCE POPS FOR
ISOLATED CONVECTIVE DEVELOPMENT FRIDAY AFTERNOON...BUT ANTICIPATE IT
WILL BE MORE FOCUSED OVER THE SOUTHERN HALF OF THE FORECAST AREA
WHERE DEEPER MOISTURE WILL RESIDE. THE W/SW FLOW WILL DRAW A SLUG OF
DRIER AIR ALOFT INTO THE LOWER GREAT LAKES IMMEDIATELY AHEAD OF THE
FRONT THAT WILL GRADUALLY BECOME SQUEEZED BY MOISTURE ADVECTING
NORTH AROUND THE BACK SIDE OF THE BERMUDA HIGH AND MOISTURE POOLING
ALONG THE BOUNDARY. THIS MAY LIMIT CONVECTIVE DEVELOPMENT OVER
NORTHERN COUNTIES FOR MUCH OF THE DAY.
FOCUS WILL SHIFT TO THE N/NW OF THE REGION BY LATE FRIDAY AFTERNOON
AS CONVECTION IS LIKELY TO DEVELOP IN THE VICINITY OF THE BOUNDARY
AND QUICKLY BECOME SEVERE AS BL SHEAR VALUES ARE ENHANCED AND
AIRMASS WILL BE MODERATELY UNSTABLE. STORMS ARE LIKELY TO ORGANIZE
INTO A MESOSCALE CONVECTIVE COMPLEX BY FRIDAY EVENING WITH
THERMODYNAMIC PROFILES SUGGESTING THE POTENTIAL FOR A SIGNIFICANT
DAMAGING WIND THREAT AS THE STORMS MOVE ACROSS THE LOWER GREAT
LAKES. THIS CONVECTION SHOULD LARGELY REMAIN TO THE NORTH OF THE
FORECAST AREA THROUGH THE EVENING...WITH PRECIP CHANCES RISING AFTER
MIDNIGHT AS THE TAIL END OF THE COMPLEX SAGS SOUTH INTO THE REGION
WITH THE COLD FRONT. AT THIS POINT...THERE IS GREATER UNCERTAINTY AS
TO THE POTENTIAL FOR CONVECTION TO MAINTAIN ITS INTENSITY OVER THE
FORECAST AREA LATE FRIDAY NIGHT. THE CORE OF THE COMPLEX IS EXPECTED
TO TRACK ACROSS THE LOWER GREAT LAKES IN CLOSER PROXIMITY TO THE
DEEPER FORCING ALOFT AND THE LOCATION OF THE LOW LEVEL JET. THE
COMPLEX IS LIKELY TO DROP A WELL DEFINED COLD POOL AND THERE IS A
POSSIBILITY THAT THIS COULD WORK INTO NORTHERN PORTIONS OF THE
FORECAST AREA BEFORE WEAKENING. AT THIS POINT...ANTICIPATE A
WEAKENING LINE OF STORMS IMPACTING THE FORECAST AREA LATE FRIDAY
NIGHT WITH THE POTENTIAL FOR STORMS TO PRODUCE DAMAGING WINDS.
THE FRONT WILL SLOW DOWN ITS FORWARD PROGRESS AS IT RUNS INTO THE
SUPPRESSED RIDGE TO OUR SOUTH. BOUNDARY LIKELY TO TAKE ALL DAY
SATURDAY AND LIKELY A PORTION OF SATURDAY NIGHT TO MOVE ACROSS THE
FORECAST AREA. LEFTOVER CONVECTION FROM FRIDAY NIGHT MAY BE ONGOING
IN A WEAKENED STATE SATURDAY MORNING...BUT EXPECT RENEWED
DEVELOPMENT THROUGHOUT THE DAY. PRECIP WATER VALUES NEAR 2
INCHES...LOW LEVEL CONVERGENCE IN VICINITY OF THE FRONT AND MODEST
INSTABILITY WILL BE THE MAIN CATALYSTS FOR CONVECTIVE DEVELOPMENT
AND INTENSITY AS DEEPER FORCING ALOFT WILL BE FOCUSED FURTHER TO THE
NORTHEAST OVER THE EASTERN GREAT LAKES AND INTO NEW ENGLAND. WHILE
STORMS WILL HAVE THE POTENTIAL TO PRODUCE DAMAGING WINDS...NOT
EXPECTING A WIDESPREAD SEVERE THREAT IN THE ABSENCE OF DEEPER SHEAR
AND BETTER FORCING ALOFT. POTENTIAL FOR HEAVY RAINFALL AND LOCALIZED
FLOODING WITH THE HIGH PWATS. WILL CARRY HIGH CHANCE/LIKELY POPS
SATURDAY...WITH PRECIP CHANCES ENDING LATE SATURDAY NIGHT AS THE
FRONT SETTLES NEAR THE OHIO RIVER.
TEMPS...SEVERAL FACTORS SUGGESTIVE THAT FRIDAY COULD BE THE HOTTEST
DAY OF THIS RECENT STRETCH OF HOT DAYS FOR MUCH OF THE FORECAST AREA.
850MB TEMPS RISE TO 20-21C AND COMBINED WITH THE STRONGER W/SW FLOW
WHICH SHOULD ENHANCE BOUNDARY LAYER MIXING AND COMPRESSIONAL HEATING
AHEAD OF THE FRONT...COULD VERY WELL SEE TEMPS MAX OUT AT 94-95 IN
SOME LOCATIONS. MOS GUIDANCE LOOKS FAR TOO COOL AND WILL GENERALLY
BE 2-3 DEGREES WARMER. MOS GUIDANCE WITH HIGHS MAINLY IN THE UPPER
80S LOOKED REASONABLE FOR SATURDAY WITH STORMS AND INCREASED CLOUD
COVERAGE. LOWS WILL REMAIN IN THE 70S TONIGHT AND FRIDAY NIGHT...
FALLING BACK INTO THE 60S SATURDAY NIGHT AS COOLER DRIER AIR EXPANDS
SOUTH BEHIND THE FRONT.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 237 PM EDT THU JUL 18 2013
THE LONG TERM FORECAST IS CHARACTERIZED BY NORTHWEST FLOW ALOFT AND
A SERIES OF UPPER DISTURBANCES MOVING THROUGH THIS FLOW AND
PROMPTING THUNDERSTORM CHANCES. GENERALLY ACCEPTED ALLBLEND AS
TIMING OUT INDIVIDUAL WAVES OF THUNDERSTORMS IN THIS TYPE OF PATTERN
IS DIFFICULT ESPECIALLY WITH MODEL DISAGREEMENTS ON TIMING. HIGH
TEMPERATURES LOOK LIKE THEY WILL BE A COUPLE DEGREES BELOW NORMAL
FOR THE PERIOD WITH THICKNESSES LOWER IN THE NORTHWEST FLOW.
&&
.AVIATION /DISCUSSION FOR 181800Z TAF ISSUANCE/...
ISSUED AT 1250 PM EDT THU JUL 18 2013
BROAD HIGH PRESSURE CONTINUES OVER THE SITES. VFR CU SHOULD BE
AROUND FOR THE AFTERNOON BUT DISSIPATE WITH SUNSET. LIGHT AND
VARIABLE TO CALM WINDS OVERNIGHT WITH MOIST AIR AT LOW LEVELS UNDER
SUBSIDENCE WILL PRODUCE CONDITIONS VERY SIMILAR TO THIS MORNING SO
USED PERSISTENCE FOR OVERNIGHT FOG FORECAST. WILL BRING IN MVFR
FOG AT OUTLYING SITES SOMETIME AFTER 7Z. WILL ALSO INCLUDE SOME
IFR AT KLAF SIMILAR TO THIS MORNING. FRIDAY AFTERNOON CU WILL FORM
ONCE AGAIN AND COULD SEE A CHANCE FOR THUNDER BUT IS LOW ENOUGH TO
KEEP OUT OF THE FORECAST FOR NOW.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...SMF/RYAN
SHORT TERM...RYAN
LONG TERM....CP
AVIATION...CP
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
102 PM EDT THU JUL 18 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 346 AM EDT THU JUL 18 2013
HOT AND HUMID WEATHER WILL CONTINUE THROUGH FRIDAY AS THE RIDGE
ALOFT GRADUALLY SHIFTS TO THE SOUTH. A VIGOROUS UPPER LEVEL LOW WILL
TRACK THROUGH EASTERN CANADA WITH A COLD FRONT TRACKING SOUTH INTO
THE REGION ON SATURDAY. THE ARRIVAL AND PASSAGE OF THE FRONT WILL
BRING NUMEROUS SHOWERS AND THUNDERSTORMS TO CENTRAL INDIANA LATE
FRIDAY NIGHT THROUGH SATURDAY EVENING. COOLER DRIER AIR WILL BRIEFLY
BUILD INTO THE REGION ON SUNDAY AS HIGH PRESSURE PASSES THROUGH THE
GREAT LAKES. CHANCES FOR THUNDERSTORMS WILL RETURN BY LATE SUNDAY
NIGHT AND MONDAY AND CONTINUE THROUGH THE MIDDLE OF NEXT WEEK AS THE
FRONTAL BOUNDARY DRIFTS BACK NORTH INTO THE AREA.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1042 AM EDT THU JUL 18 2013
FEW IF ANY CHANGES NEEDED AT THIS TIME. FORECAST APPEARS TO BE IN
GOOD SHAPE. PREVIOUS DISCUSSION FOLLOWS...
ANOTHER MUGGY START EARLY THIS MORNING AS 07Z TEMPS GENERALLY IN THE
MID AND UPPER 70S. CONVECTIVE DEBRIS CLOUDS CONTINUE TO DRIFT INTO
THE SOUTHERN HALF OF THE FORECAST AREA AS A WEAK UPPER WAVE
CURRENTLY TRACKS ACROSS THE TENNESSEE VALLEY.
THE UPPER LEVEL HIGH REMAINS PARKED ACROSS CENTRAL INDIANA WITH MID
LEVEL HEIGHT MAXES STILL AROUND 597DAM. THESE HEIGHTS WILL SLOWLY
FALL THROUGH THE DAY AS THE RIDGE GRADUALLY BUCKLES IN RESPONSE TO A
DEVELOPING STRONG UPPER LOW GETTING ITS ACT TOGETHER ACROSS JAMES
BAY. THE AFOREMENTIONED WEAK WAVE ALOFT OVER THE TENNESSEE VALLEY
WILL DRIFT WEST THROUGH THE DAY AND SHOULD BE LOCATED OVER THE LOWER
OHIO VALLEY BY LATE DAY. SCATTERED CONVECTION ASSOCIATED WITH THIS
FEATURE SHOULD DEVELOP ACROSS KENTUCKY AND TENNESSEE AND MAY EVEN
SEE A FEW STORMS MAKE IT INTO OUR SOUTHERN COUNTIES. THE HRRR LOOKS
TO BE OVERDOING CONVECTIVE DEVELOPMENT IN GENERAL BUT HINTS AT THIS
IDEA AS WELL. CONSIDERING THE NATURE OF THE AIRMASS AND THE
PROXIMITY OF THE UPPER WAVE...ISOLATED POPS ARE WARRANTED ACROSS FAR
SOUTHERN COUNTIES FOR THIS AFTERNOON. FURTHER NORTH DESPITE THE
GRADUALLY LOWERING MID LEVEL HEIGHTS...THE RIDGING ALOFT AND CAP
NEAR 650MB ARE LIKELY TO REMAIN TOO STRONG FOR ANY SUBSTANTIAL
CONVECTIVE DEVELOPMENT. WHILE AN ISOLATED SHOWER CANNOT BE RULED
OUT...COVERAGE LIKELY TO BE SO LOW TO PRECLUDE ANY MENTION IN THE
FORECAST AT THIS TIME.
TEMPS...LOW LEVEL THERMALS WILL BE SIMILAR TO WEDNESDAY WITH 850MB
TEMPS RISING TO AROUND 19-20C. LIKEWISE EXPECT HIGH TEMPS TO BE
SIMILAR TO WEDNESDAY AS WELL...REACHING THE 92-94 DEGREE RANGE FOR
MUCH OF THE FORECAST AREA. GENERALLY GOING A DEGREE OR TWO ABOVE
MOS. MAX HEAT INDICES WILL RISE TO AROUND 100 DEGREES AGAIN THIS
AFTERNOON...AND MAY TOP OUT JUST A TOUCH WARMER THAN WEDNESDAY AS
SLIGHTLY DEEPER MOISTURE IS PULLED NORTH INTO THE REGION. HAVE NO
PLANS TO INTRODUCE A HEAT ADVISORY AS THESE VALUES REMAINS BELOW
CRITERIA. WILL CONTINUE WITH THE SPS.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 346 AM EDT THU JUL 18 2013
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES AND TEMPS AS A COLD
FRONT DROPS SOUTH THROUGH THE REGION SATURDAY. MODELS GENERALLY IN
VERY GOOD AGREEMENT ON MAIN FEATURES THROUGHOUT THE SHORT TERM.
RIDGING ALOFT WILL CONTINUE TO SINK SOUTH AND FLATTEN AS THE DEEP
UPPER LOW DIVES ACROSS NORTHERN ONTARIO...THEN PINWHEELS INTO THE
CANADIAN MARITIMES BY SUNDAY MORNING. ROBUST CONVECTIVE DEVELOPMENT
WILL TAKE PLACE TONIGHT OVER THE UPPER MISSISSIPPI VALLEY AND
NORTHERN GREAT LAKES IN PROXIMITY TO THE COLD FRONT. THIS FRONT WILL
SINK SOUTH AND SHOULD BE LOCATED ACROSS THE WESTERN GREAT LAKES BY
FRIDAY AFTERNOON. THE FLATTENING OF THE RIDGE AND APPROACH OF THE
COLD FRONT WILL ENCOURAGE A W/SW FLOW THROUGH THE LOWER LEVELS ON
FRIDAY...WITH POTENTIAL FOR SOME GUSTS TO NEAR 20-25KTS OVER
NORTHERN COUNTIES BY AFTERNOON AS A LOW LEVEL JET ACCOMPANIES THE
BOUNDARY THROUGH THE GREAT LAKES. WILL MAINTAIN LOW CHANCE POPS FOR
ISOLATED CONVECTIVE DEVELOPMENT FRIDAY AFTERNOON...BUT ANTICIPATE IT
WILL BE MORE FOCUSED OVER THE SOUTHERN HALF OF THE FORECAST AREA
WHERE DEEPER MOISTURE WILL RESIDE. THE W/SW FLOW WILL DRAW A SLUG OF
DRIER AIR ALOFT INTO THE LOWER GREAT LAKES IMMEDIATELY AHEAD OF THE
FRONT THAT WILL GRADUALLY BECOME SQUEEZED BY MOISTURE ADVECTING
NORTH AROUND THE BACK SIDE OF THE BERMUDA HIGH AND MOISTURE POOLING
ALONG THE BOUNDARY. THIS MAY LIMIT CONVECTIVE DEVELOPMENT OVER
NORTHERN COUNTIES FOR MUCH OF THE DAY.
FOCUS WILL SHIFT TO THE N/NW OF THE REGION BY LATE FRIDAY AFTERNOON
AS CONVECTION IS LIKELY TO DEVELOP IN THE VICINITY OF THE BOUNDARY
AND QUICKLY BECOME SEVERE AS BL SHEAR VALUES ARE ENHANCED AND
AIRMASS WILL BE MODERATELY UNSTABLE. STORMS ARE LIKELY TO ORGANIZE
INTO A MESOSCALE CONVECTIVE COMPLEX BY FRIDAY EVENING WITH
THERMODYNAMIC PROFILES SUGGESTING THE POTENTIAL FOR A SIGNIFICANT
DAMAGING WIND THREAT AS THE STORMS MOVE ACROSS THE LOWER GREAT
LAKES. THIS CONVECTION SHOULD LARGELY REMAIN TO THE NORTH OF THE
FORECAST AREA THROUGH THE EVENING...WITH PRECIP CHANCES RISING AFTER
MIDNIGHT AS THE TAIL END OF THE COMPLEX SAGS SOUTH INTO THE REGION
WITH THE COLD FRONT. AT THIS POINT...THERE IS GREATER UNCERTAINTY AS
TO THE POTENTIAL FOR CONVECTION TO MAINTAIN ITS INTENSITY OVER THE
FORECAST AREA LATE FRIDAY NIGHT. THE CORE OF THE COMPLEX IS EXPECTED
TO TRACK ACROSS THE LOWER GREAT LAKES IN CLOSER PROXIMITY TO THE
DEEPER FORCING ALOFT AND THE LOCATION OF THE LOW LEVEL JET. THE
COMPLEX IS LIKELY TO DROP A WELL DEFINED COLD POOL AND THERE IS A
POSSIBILITY THAT THIS COULD WORK INTO NORTHERN PORTIONS OF THE
FORECAST AREA BEFORE WEAKENING. AT THIS POINT...ANTICIPATE A
WEAKENING LINE OF STORMS IMPACTING THE FORECAST AREA LATE FRIDAY
NIGHT WITH THE POTENTIAL FOR STORMS TO PRODUCE DAMAGING WINDS.
THE FRONT WILL SLOW DOWN ITS FORWARD PROGRESS AS IT RUNS INTO THE
SUPPRESSED RIDGE TO OUR SOUTH. BOUNDARY LIKELY TO TAKE ALL DAY
SATURDAY AND LIKELY A PORTION OF SATURDAY NIGHT TO MOVE ACROSS THE
FORECAST AREA. LEFTOVER CONVECTION FROM FRIDAY NIGHT MAY BE ONGOING
IN A WEAKENED STATE SATURDAY MORNING...BUT EXPECT RENEWED
DEVELOPMENT THROUGHOUT THE DAY. PRECIP WATER VALUES NEAR 2
INCHES...LOW LEVEL CONVERGENCE IN VICINITY OF THE FRONT AND MODEST
INSTABILITY WILL BE THE MAIN CATALYSTS FOR CONVECTIVE DEVELOPMENT
AND INTENSITY AS DEEPER FORCING ALOFT WILL BE FOCUSED FURTHER TO THE
NORTHEAST OVER THE EASTERN GREAT LAKES AND INTO NEW ENGLAND. WHILE
STORMS WILL HAVE THE POTENTIAL TO PRODUCE DAMAGING WINDS...NOT
EXPECTING A WIDESPREAD SEVERE THREAT IN THE ABSENCE OF DEEPER SHEAR
AND BETTER FORCING ALOFT. POTENTIAL FOR HEAVY RAINFALL AND LOCALIZED
FLOODING WITH THE HIGH PWATS. WILL CARRY HIGH CHANCE/LIKELY POPS
SATURDAY...WITH PRECIP CHANCES ENDING LATE SATURDAY NIGHT AS THE
FRONT SETTLES NEAR THE OHIO RIVER.
TEMPS...SEVERAL FACTORS SUGGESTIVE THAT FRIDAY COULD BE THE HOTTEST
DAY OF THIS RECENT STRETCH OF HOT DAYS FOR MUCH OF THE FORECAST AREA.
850MB TEMPS RISE TO 20-21C AND COMBINED WITH THE STRONGER W/SW FLOW
WHICH SHOULD ENHANCE BOUNDARY LAYER MIXING AND COMPRESSIONAL HEATING
AHEAD OF THE FRONT...COULD VERY WELL SEE TEMPS MAX OUT AT 94-95 IN
SOME LOCATIONS. MOS GUIDANCE LOOKS FAR TOO COOL AND WILL GENERALLY
BE 2-3 DEGREES WARMER. MOS GUIDANCE WITH HIGHS MAINLY IN THE UPPER
80S LOOKED REASONABLE FOR SATURDAY WITH STORMS AND INCREASED CLOUD
COVERAGE. LOWS WILL REMAIN IN THE 70S TONIGHT AND FRIDAY NIGHT...
FALLING BACK INTO THE 60S SATURDAY NIGHT AS COOLER DRIER AIR EXPANDS
SOUTH BEHIND THE FRONT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 305 AM EDT THU JUL 18 2013
TEMPERATURES WILL NOT BE QUITE AS HOT DURING THE LONG TERM AS THE
UPPER HIGH WILL BE OVER THE WESTERN U.S. AND HEIGHTS LOWER A LITTLE
ACROSS THE GREAT LAKES. A WEAK COLD FRONT WILL STALL ACROSS THE
GREAT LAKES SUNDAY AS HIGH PRESSURE MOVES EAST ACROSS THE GREAT
LAKES. ALL AREAS SHOULD REMAIN DRY UNDER THIS SITUATION SUNDAY.
AFTER SUNDAY WILL MENTION CHANCE POPS FROM LATE SUNDAY NIGHT THROUGH
DAY 7 AS A SERIES OF WEAK DISTURBANCES MOVE EAST ALONG THIS STALLED
FRONT. THERE IS SOME DISCREPANCY ON TIMING OF THESE DISTURBANCES
BETWEEN THE DIFFERENT MODELS. HOWEVER MODEL CONSENSUS SEEMS TO POINT
TOWARDS ONE OF THE MAIN DISTURBANCES MOVING THROUGH AROUND MONDAY
AND ANOTHER ONE EITHER MOVING ACROSS OUR REGION TUESDAY NIGHT OR
WEDNESDAY.
CUT ALL BLEND POPS A LITTLE SUNDAY AND SUNDAY EVENING.
OTHERWISE...I DID NOT MAKE ANY SIGNIFICANT CHANGES TO POPS OR
TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR 181800Z TAF ISSUANCE/...
ISSUED AT 1250 PM EDT THU JUL 18 2013
BROAD HIGH PRESSURE CONTINUES OVER THE SITES. VFR CU SHOULD BE
AROUND FOR THE AFTERNOON BUT DISSIPATE WITH SUNSET. LIGHT AND
VARIABLE TO CALM WINDS OVERNIGHT WITH MOIST AIR AT LOW LEVELS UNDER
SUBSIDENCE WILL PRODUCE CONDITIONS VERY SIMILAR TO THIS MORNING SO
USED PERSISTENCE FOR OVERNIGHT FOG FORECAST. WILL BRING IN MVFR
FOG AT OUTLYING SITES SOMETIME AFTER 7Z. WILL ALSO INCLUDE SOME
IFR AT KLAF SIMILAR TO THIS MORNING. FRIDAY AFTERNOON CU WILL FORM
ONCE AGAIN AND COULD SEE A CHANCE FOR THUNDER BUT IS LOW ENOUGH TO
KEEP OUT OF THE FORECAST FOR NOW.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...SMF/RYAN
SHORT TERM...RYAN
LONG TERM....JH
AVIATION...CP
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1043 AM EDT THU JUL 18 2013
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 346 AM EDT THU JUL 18 2013
HOT AND HUMID WEATHER WILL CONTINUE THROUGH FRIDAY AS THE RIDGE
ALOFT GRADUALLY SHIFTS TO THE SOUTH. A VIGOROUS UPPER LEVEL LOW WILL
TRACK THROUGH EASTERN CANADA WITH A COLD FRONT TRACKING SOUTH INTO
THE REGION ON SATURDAY. THE ARRIVAL AND PASSAGE OF THE FRONT WILL
BRING NUMEROUS SHOWERS AND THUNDERSTORMS TO CENTRAL INDIANA LATE
FRIDAY NIGHT THROUGH SATURDAY EVENING. COOLER DRIER AIR WILL BRIEFLY
BUILD INTO THE REGION ON SUNDAY AS HIGH PRESSURE PASSES THROUGH THE
GREAT LAKES. CHANCES FOR THUNDERSTORMS WILL RETURN BY LATE SUNDAY
NIGHT AND MONDAY AND CONTINUE THROUGH THE MIDDLE OF NEXT WEEK AS THE
FRONTAL BOUNDARY DRIFTS BACK NORTH INTO THE AREA.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1042 AM EDT THU JUL 18 2013
FEW IF ANY CHANGES NEEDED AT THIS TIME. FORECAST APPEARS TO BE IN
GOOD SHAPE. PREVIOUS DISCUSSION FOLLOWS...
ANOTHER MUGGY START EARLY THIS MORNING AS 07Z TEMPS GENERALLY IN THE
MID AND UPPER 70S. CONVECTIVE DEBRIS CLOUDS CONTINUE TO DRIFT INTO
THE SOUTHERN HALF OF THE FORECAST AREA AS A WEAK UPPER WAVE
CURRENTLY TRACKS ACROSS THE TENNESSEE VALLEY.
THE UPPER LEVEL HIGH REMAINS PARKED ACROSS CENTRAL INDIANA WITH MID
LEVEL HEIGHT MAXES STILL AROUND 597DAM. THESE HEIGHTS WILL SLOWLY
FALL THROUGH THE DAY AS THE RIDGE GRADUALLY BUCKLES IN RESPONSE TO A
DEVELOPING STRONG UPPER LOW GETTING ITS ACT TOGETHER ACROSS JAMES
BAY. THE AFOREMENTIONED WEAK WAVE ALOFT OVER THE TENNESSEE VALLEY
WILL DRIFT WEST THROUGH THE DAY AND SHOULD BE LOCATED OVER THE LOWER
OHIO VALLEY BY LATE DAY. SCATTERED CONVECTION ASSOCIATED WITH THIS
FEATURE SHOULD DEVELOP ACROSS KENTUCKY AND TENNESSEE AND MAY EVEN
SEE A FEW STORMS MAKE IT INTO OUR SOUTHERN COUNTIES. THE HRRR LOOKS
TO BE OVERDOING CONVECTIVE DEVELOPMENT IN GENERAL BUT HINTS AT THIS
IDEA AS WELL. CONSIDERING THE NATURE OF THE AIRMASS AND THE
PROXIMITY OF THE UPPER WAVE...ISOLATED POPS ARE WARRANTED ACROSS FAR
SOUTHERN COUNTIES FOR THIS AFTERNOON. FURTHER NORTH DESPITE THE
GRADUALLY LOWERING MID LEVEL HEIGHTS...THE RIDGING ALOFT AND CAP
NEAR 650MB ARE LIKELY TO REMAIN TOO STRONG FOR ANY SUBSTANTIAL
CONVECTIVE DEVELOPMENT. WHILE AN ISOLATED SHOWER CANNOT BE RULED
OUT...COVERAGE LIKELY TO BE SO LOW TO PRECLUDE ANY MENTION IN THE
FORECAST AT THIS TIME.
TEMPS...LOW LEVEL THERMALS WILL BE SIMILAR TO WEDNESDAY WITH 850MB
TEMPS RISING TO AROUND 19-20C. LIKEWISE EXPECT HIGH TEMPS TO BE
SIMILAR TO WEDNESDAY AS WELL...REACHING THE 92-94 DEGREE RANGE FOR
MUCH OF THE FORECAST AREA. GENERALLY GOING A DEGREE OR TWO ABOVE
MOS. MAX HEAT INDICES WILL RISE TO AROUND 100 DEGREES AGAIN THIS
AFTERNOON...AND MAY TOP OUT JUST A TOUCH WARMER THAN WEDNESDAY AS
SLIGHTLY DEEPER MOISTURE IS PULLED NORTH INTO THE REGION. HAVE NO
PLANS TO INTRODUCE A HEAT ADVISORY AS THESE VALUES REMAINS BELOW
CRITERIA. WILL CONTINUE WITH THE SPS.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 346 AM EDT THU JUL 18 2013
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES AND TEMPS AS A COLD
FRONT DROPS SOUTH THROUGH THE REGION SATURDAY. MODELS GENERALLY IN
VERY GOOD AGREEMENT ON MAIN FEATURES THROUGHOUT THE SHORT TERM.
RIDGING ALOFT WILL CONTINUE TO SINK SOUTH AND FLATTEN AS THE DEEP
UPPER LOW DIVES ACROSS NORTHERN ONTARIO...THEN PINWHEELS INTO THE
CANADIAN MARITIMES BY SUNDAY MORNING. ROBUST CONVECTIVE DEVELOPMENT
WILL TAKE PLACE TONIGHT OVER THE UPPER MISSISSIPPI VALLEY AND
NORTHERN GREAT LAKES IN PROXIMITY TO THE COLD FRONT. THIS FRONT WILL
SINK SOUTH AND SHOULD BE LOCATED ACROSS THE WESTERN GREAT LAKES BY
FRIDAY AFTERNOON. THE FLATTENING OF THE RIDGE AND APPROACH OF THE
COLD FRONT WILL ENCOURAGE A W/SW FLOW THROUGH THE LOWER LEVELS ON
FRIDAY...WITH POTENTIAL FOR SOME GUSTS TO NEAR 20-25KTS OVER
NORTHERN COUNTIES BY AFTERNOON AS A LOW LEVEL JET ACCOMPANIES THE
BOUNDARY THROUGH THE GREAT LAKES. WILL MAINTAIN LOW CHANCE POPS FOR
ISOLATED CONVECTIVE DEVELOPMENT FRIDAY AFTERNOON...BUT ANTICIPATE IT
WILL BE MORE FOCUSED OVER THE SOUTHERN HALF OF THE FORECAST AREA
WHERE DEEPER MOISTURE WILL RESIDE. THE W/SW FLOW WILL DRAW A SLUG OF
DRIER AIR ALOFT INTO THE LOWER GREAT LAKES IMMEDIATELY AHEAD OF THE
FRONT THAT WILL GRADUALLY BECOME SQUEEZED BY MOISTURE ADVECTING
NORTH AROUND THE BACK SIDE OF THE BERMUDA HIGH AND MOISTURE POOLING
ALONG THE BOUNDARY. THIS MAY LIMIT CONVECTIVE DEVELOPMENT OVER
NORTHERN COUNTIES FOR MUCH OF THE DAY.
FOCUS WILL SHIFT TO THE N/NW OF THE REGION BY LATE FRIDAY AFTERNOON
AS CONVECTION IS LIKELY TO DEVELOP IN THE VICINITY OF THE BOUNDARY
AND QUICKLY BECOME SEVERE AS BL SHEAR VALUES ARE ENHANCED AND
AIRMASS WILL BE MODERATELY UNSTABLE. STORMS ARE LIKELY TO ORGANIZE
INTO A MESOSCALE CONVECTIVE COMPLEX BY FRIDAY EVENING WITH
THERMODYNAMIC PROFILES SUGGESTING THE POTENTIAL FOR A SIGNIFICANT
DAMAGING WIND THREAT AS THE STORMS MOVE ACROSS THE LOWER GREAT
LAKES. THIS CONVECTION SHOULD LARGELY REMAIN TO THE NORTH OF THE
FORECAST AREA THROUGH THE EVENING...WITH PRECIP CHANCES RISING AFTER
MIDNIGHT AS THE TAIL END OF THE COMPLEX SAGS SOUTH INTO THE REGION
WITH THE COLD FRONT. AT THIS POINT...THERE IS GREATER UNCERTAINTY AS
TO THE POTENTIAL FOR CONVECTION TO MAINTAIN ITS INTENSITY OVER THE
FORECAST AREA LATE FRIDAY NIGHT. THE CORE OF THE COMPLEX IS EXPECTED
TO TRACK ACROSS THE LOWER GREAT LAKES IN CLOSER PROXIMITY TO THE
DEEPER FORCING ALOFT AND THE LOCATION OF THE LOW LEVEL JET. THE
COMPLEX IS LIKELY TO DROP A WELL DEFINED COLD POOL AND THERE IS A
POSSIBILITY THAT THIS COULD WORK INTO NORTHERN PORTIONS OF THE
FORECAST AREA BEFORE WEAKENING. AT THIS POINT...ANTICIPATE A
WEAKENING LINE OF STORMS IMPACTING THE FORECAST AREA LATE FRIDAY
NIGHT WITH THE POTENTIAL FOR STORMS TO PRODUCE DAMAGING WINDS.
THE FRONT WILL SLOW DOWN ITS FORWARD PROGRESS AS IT RUNS INTO THE
SUPPRESSED RIDGE TO OUR SOUTH. BOUNDARY LIKELY TO TAKE ALL DAY
SATURDAY AND LIKELY A PORTION OF SATURDAY NIGHT TO MOVE ACROSS THE
FORECAST AREA. LEFTOVER CONVECTION FROM FRIDAY NIGHT MAY BE ONGOING
IN A WEAKENED STATE SATURDAY MORNING...BUT EXPECT RENEWED
DEVELOPMENT THROUGHOUT THE DAY. PRECIP WATER VALUES NEAR 2
INCHES...LOW LEVEL CONVERGENCE IN VICINITY OF THE FRONT AND MODEST
INSTABILITY WILL BE THE MAIN CATALYSTS FOR CONVECTIVE DEVELOPMENT
AND INTENSITY AS DEEPER FORCING ALOFT WILL BE FOCUSED FURTHER TO THE
NORTHEAST OVER THE EASTERN GREAT LAKES AND INTO NEW ENGLAND. WHILE
STORMS WILL HAVE THE POTENTIAL TO PRODUCE DAMAGING WINDS...NOT
EXPECTING A WIDESPREAD SEVERE THREAT IN THE ABSENCE OF DEEPER SHEAR
AND BETTER FORCING ALOFT. POTENTIAL FOR HEAVY RAINFALL AND LOCALIZED
FLOODING WITH THE HIGH PWATS. WILL CARRY HIGH CHANCE/LIKELY POPS
SATURDAY...WITH PRECIP CHANCES ENDING LATE SATURDAY NIGHT AS THE
FRONT SETTLES NEAR THE OHIO RIVER.
TEMPS...SEVERAL FACTORS SUGGESTIVE THAT FRIDAY COULD BE THE HOTTEST
DAY OF THIS RECENT STRETCH OF HOT DAYS FOR MUCH OF THE FORECAST AREA.
850MB TEMPS RISE TO 20-21C AND COMBINED WITH THE STRONGER W/SW FLOW
WHICH SHOULD ENHANCE BOUNDARY LAYER MIXING AND COMPRESSIONAL HEATING
AHEAD OF THE FRONT...COULD VERY WELL SEE TEMPS MAX OUT AT 94-95 IN
SOME LOCATIONS. MOS GUIDANCE LOOKS FAR TOO COOL AND WILL GENERALLY
BE 2-3 DEGREES WARMER. MOS GUIDANCE WITH HIGHS MAINLY IN THE UPPER
80S LOOKED REASONABLE FOR SATURDAY WITH STORMS AND INCREASED CLOUD
COVERAGE. LOWS WILL REMAIN IN THE 70S TONIGHT AND FRIDAY NIGHT...
FALLING BACK INTO THE 60S SATURDAY NIGHT AS COOLER DRIER AIR EXPANDS
SOUTH BEHIND THE FRONT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 305 AM EDT THU JUL 18 2013
TEMPERATURES WILL NOT BE QUITE AS HOT DURING THE LONG TERM AS THE
UPPER HIGH WILL BE OVER THE WESTERN U.S. AND HEIGHTS LOWER A LITTLE
ACROSS THE GREAT LAKES. A WEAK COLD FRONT WILL STALL ACROSS THE
GREAT LAKES SUNDAY AS HIGH PRESSURE MOVES EAST ACROSS THE GREAT
LAKES. ALL AREAS SHOULD REMAIN DRY UNDER THIS SITUATION SUNDAY.
AFTER SUNDAY WILL MENTION CHANCE POPS FROM LATE SUNDAY NIGHT THROUGH
DAY 7 AS A SERIES OF WEAK DISTURBANCES MOVE EAST ALONG THIS STALLED
FRONT. THERE IS SOME DISCREPANCY ON TIMING OF THESE DISTURBANCES
BETWEEN THE DIFFERENT MODELS. HOWEVER MODEL CONSENSUS SEEMS TO POINT
TOWARDS ONE OF THE MAIN DISTURBANCES MOVING THROUGH AROUND MONDAY
AND ANOTHER ONE EITHER MOVING ACROSS OUR REGION TUESDAY NIGHT OR
WEDNESDAY.
CUT ALL BLEND POPS A LITTLE SUNDAY AND SUNDAY EVENING.
OTHERWISE...I DID NOT MAKE ANY SIGNIFICANT CHANGES TO POPS OR
TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR THE 181500Z TAF ISSUANCE/...
ISSUED AT 1026 AM EDT THU JUL 18 2013
TAF UPDATED TO TWEAK CURRENT CONDITIONS. PREVIOUS DISCUSSION
FOLLOWS...
VISIBILITY RESTRICTIONS POSSIBLE AT KBMG/KHUF/KLAF AFTER 06Z
TONIGHT. OTHERWISE...TAFS WILL BE VFR.
HIGH PRESSURE BOTH SURFACE AND ALOFT WILL CONTINUE ACROSS THE REGION.
EXPECT SCATTERED CU AROUND 4 THOUSAND MOST OF TODAY. PATTERN IS
VERY STAGNANT AND WILL LEAN HEAVILY TOWARDS PERSISTENCE. CU SHOULD
DISSIPATE SHORTLY AFTER SUNSET AND FOG WILL REDEVELOP AGAIN LATE
TONIGHT SIMILAR TO LAST NIGHT. WINDS WILL BE FROM THE WEST AT 5
KNOTS OR LESS TODAY AND LIGHT TONIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...SMF/RYAN
SHORT TERM...RYAN
LONG TERM....JH
AVIATION...JH/CP
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1026 AM EDT THU JUL 18 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 346 AM EDT THU JUL 18 2013
HOT AND HUMID WEATHER WILL CONTINUE THROUGH FRIDAY AS THE RIDGE
ALOFT GRADUALLY SHIFTS TO THE SOUTH. A VIGOROUS UPPER LEVEL LOW WILL
TRACK THROUGH EASTERN CANADA WITH A COLD FRONT TRACKING SOUTH INTO
THE REGION ON SATURDAY. THE ARRIVAL AND PASSAGE OF THE FRONT WILL
BRING NUMEROUS SHOWERS AND THUNDERSTORMS TO CENTRAL INDIANA LATE
FRIDAY NIGHT THROUGH SATURDAY EVENING. COOLER DRIER AIR WILL BRIEFLY
BUILD INTO THE REGION ON SUNDAY AS HIGH PRESSURE PASSES THROUGH THE
GREAT LAKES. CHANCES FOR THUNDERSTORMS WILL RETURN BY LATE SUNDAY
NIGHT AND MONDAY AND CONTINUE THROUGH THE MIDDLE OF NEXT WEEK AS THE
FRONTAL BOUNDARY DRIFTS BACK NORTH INTO THE AREA.
&&
.NEAR TERM /TODAY/...
ISSUED AT 346 AM EDT THU JUL 18 2013
ANOTHER MUGGY START EARLY THIS MORNING AS 07Z TEMPS GENERALLY IN THE
MID AND UPPER 70S. CONVECTIVE DEBRIS CLOUDS CONTINUE TO DRIFT INTO
THE SOUTHERN HALF OF THE FORECAST AREA AS A WEAK UPPER WAVE
CURRENTLY TRACKS ACROSS THE TENNESSEE VALLEY.
THE UPPER LEVEL HIGH REMAINS PARKED ACROSS CENTRAL INDIANA WITH MID
LEVEL HEIGHT MAXES STILL AROUND 597DAM. THESE HEIGHTS WILL SLOWLY
FALL THROUGH THE DAY AS THE RIDGE GRADUALLY BUCKLES IN RESPONSE TO A
DEVELOPING STRONG UPPER LOW GETTING ITS ACT TOGETHER ACROSS JAMES
BAY. THE AFOREMENTIONED WEAK WAVE ALOFT OVER THE TENNESSEE VALLEY
WILL DRIFT WEST THROUGH THE DAY AND SHOULD BE LOCATED OVER THE LOWER
OHIO VALLEY BY LATE DAY. SCATTERED CONVECTION ASSOCIATED WITH THIS
FEATURE SHOULD DEVELOP ACROSS KENTUCKY AND TENNESSEE AND MAY EVEN
SEE A FEW STORMS MAKE IT INTO OUR SOUTHERN COUNTIES. THE HRRR LOOKS
TO BE OVERDOING CONVECTIVE DEVELOPMENT IN GENERAL BUT HINTS AT THIS
IDEA AS WELL. CONSIDERING THE NATURE OF THE AIRMASS AND THE
PROXIMITY OF THE UPPER WAVE...ISOLATED POPS ARE WARRANTED ACROSS FAR
SOUTHERN COUNTIES FOR THIS AFTERNOON. FURTHER NORTH DESPITE THE
GRADUALLY LOWERING MID LEVEL HEIGHTS...THE RIDGING ALOFT AND CAP
NEAR 650MB ARE LIKELY TO REMAIN TOO STRONG FOR ANY SUBSTANTIAL
CONVECTIVE DEVELOPMENT. WHILE AN ISOLATED SHOWER CANNOT BE RULED
OUT...COVERAGE LIKELY TO BE SO LOW TO PRECLUDE ANY MENTION IN THE
FORECAST AT THIS TIME.
TEMPS...LOW LEVEL THERMALS WILL BE SIMILAR TO WEDNESDAY WITH 850MB
TEMPS RISING TO AROUND 19-20C. LIKEWISE EXPECT HIGH TEMPS TO BE
SIMILAR TO WEDNESDAY AS WELL...REACHING THE 92-94 DEGREE RANGE FOR
MUCH OF THE FORECAST AREA. GENERALLY GOING A DEGREE OR TWO ABOVE
MOS. MAX HEAT INDICES WILL RISE TO AROUND 100 DEGREES AGAIN THIS
AFTERNOON...AND MAY TOP OUT JUST A TOUCH WARMER THAN WEDNESDAY AS
SLIGHTLY DEEPER MOISTURE IS PULLED NORTH INTO THE REGION. HAVE NO
PLANS TO INTRODUCE A HEAT ADVISORY AS THESE VALUES REMAINS BELOW
CRITERIA. WILL CONTINUE WITH THE SPS.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 346 AM EDT THU JUL 18 2013
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES AND TEMPS AS A COLD
FRONT DROPS SOUTH THROUGH THE REGION SATURDAY. MODELS GENERALLY IN
VERY GOOD AGREEMENT ON MAIN FEATURES THROUGHOUT THE SHORT TERM.
RIDGING ALOFT WILL CONTINUE TO SINK SOUTH AND FLATTEN AS THE DEEP
UPPER LOW DIVES ACROSS NORTHERN ONTARIO...THEN PINWHEELS INTO THE
CANADIAN MARITIMES BY SUNDAY MORNING. ROBUST CONVECTIVE DEVELOPMENT
WILL TAKE PLACE TONIGHT OVER THE UPPER MISSISSIPPI VALLEY AND
NORTHERN GREAT LAKES IN PROXIMITY TO THE COLD FRONT. THIS FRONT WILL
SINK SOUTH AND SHOULD BE LOCATED ACROSS THE WESTERN GREAT LAKES BY
FRIDAY AFTERNOON. THE FLATTENING OF THE RIDGE AND APPROACH OF THE
COLD FRONT WILL ENCOURAGE A W/SW FLOW THROUGH THE LOWER LEVELS ON
FRIDAY...WITH POTENTIAL FOR SOME GUSTS TO NEAR 20-25KTS OVER
NORTHERN COUNTIES BY AFTERNOON AS A LOW LEVEL JET ACCOMPANIES THE
BOUNDARY THROUGH THE GREAT LAKES. WILL MAINTAIN LOW CHANCE POPS FOR
ISOLATED CONVECTIVE DEVELOPMENT FRIDAY AFTERNOON...BUT ANTICIPATE IT
WILL BE MORE FOCUSED OVER THE SOUTHERN HALF OF THE FORECAST AREA
WHERE DEEPER MOISTURE WILL RESIDE. THE W/SW FLOW WILL DRAW A SLUG OF
DRIER AIR ALOFT INTO THE LOWER GREAT LAKES IMMEDIATELY AHEAD OF THE
FRONT THAT WILL GRADUALLY BECOME SQUEEZED BY MOISTURE ADVECTING
NORTH AROUND THE BACK SIDE OF THE BERMUDA HIGH AND MOISTURE POOLING
ALONG THE BOUNDARY. THIS MAY LIMIT CONVECTIVE DEVELOPMENT OVER
NORTHERN COUNTIES FOR MUCH OF THE DAY.
FOCUS WILL SHIFT TO THE N/NW OF THE REGION BY LATE FRIDAY AFTERNOON
AS CONVECTION IS LIKELY TO DEVELOP IN THE VICINITY OF THE BOUNDARY
AND QUICKLY BECOME SEVERE AS BL SHEAR VALUES ARE ENHANCED AND
AIRMASS WILL BE MODERATELY UNSTABLE. STORMS ARE LIKELY TO ORGANIZE
INTO A MESOSCALE CONVECTIVE COMPLEX BY FRIDAY EVENING WITH
THERMODYNAMIC PROFILES SUGGESTING THE POTENTIAL FOR A SIGNIFICANT
DAMAGING WIND THREAT AS THE STORMS MOVE ACROSS THE LOWER GREAT
LAKES. THIS CONVECTION SHOULD LARGELY REMAIN TO THE NORTH OF THE
FORECAST AREA THROUGH THE EVENING...WITH PRECIP CHANCES RISING AFTER
MIDNIGHT AS THE TAIL END OF THE COMPLEX SAGS SOUTH INTO THE REGION
WITH THE COLD FRONT. AT THIS POINT...THERE IS GREATER UNCERTAINTY AS
TO THE POTENTIAL FOR CONVECTION TO MAINTAIN ITS INTENSITY OVER THE
FORECAST AREA LATE FRIDAY NIGHT. THE CORE OF THE COMPLEX IS EXPECTED
TO TRACK ACROSS THE LOWER GREAT LAKES IN CLOSER PROXIMITY TO THE
DEEPER FORCING ALOFT AND THE LOCATION OF THE LOW LEVEL JET. THE
COMPLEX IS LIKELY TO DROP A WELL DEFINED COLD POOL AND THERE IS A
POSSIBILITY THAT THIS COULD WORK INTO NORTHERN PORTIONS OF THE
FORECAST AREA BEFORE WEAKENING. AT THIS POINT...ANTICIPATE A
WEAKENING LINE OF STORMS IMPACTING THE FORECAST AREA LATE FRIDAY
NIGHT WITH THE POTENTIAL FOR STORMS TO PRODUCE DAMAGING WINDS.
THE FRONT WILL SLOW DOWN ITS FORWARD PROGRESS AS IT RUNS INTO THE
SUPPRESSED RIDGE TO OUR SOUTH. BOUNDARY LIKELY TO TAKE ALL DAY
SATURDAY AND LIKELY A PORTION OF SATURDAY NIGHT TO MOVE ACROSS THE
FORECAST AREA. LEFTOVER CONVECTION FROM FRIDAY NIGHT MAY BE ONGOING
IN A WEAKENED STATE SATURDAY MORNING...BUT EXPECT RENEWED
DEVELOPMENT THROUGHOUT THE DAY. PRECIP WATER VALUES NEAR 2
INCHES...LOW LEVEL CONVERGENCE IN VICINITY OF THE FRONT AND MODEST
INSTABILITY WILL BE THE MAIN CATALYSTS FOR CONVECTIVE DEVELOPMENT
AND INTENSITY AS DEEPER FORCING ALOFT WILL BE FOCUSED FURTHER TO THE
NORTHEAST OVER THE EASTERN GREAT LAKES AND INTO NEW ENGLAND. WHILE
STORMS WILL HAVE THE POTENTIAL TO PRODUCE DAMAGING WINDS...NOT
EXPECTING A WIDESPREAD SEVERE THREAT IN THE ABSENCE OF DEEPER SHEAR
AND BETTER FORCING ALOFT. POTENTIAL FOR HEAVY RAINFALL AND LOCALIZED
FLOODING WITH THE HIGH PWATS. WILL CARRY HIGH CHANCE/LIKELY POPS
SATURDAY...WITH PRECIP CHANCES ENDING LATE SATURDAY NIGHT AS THE
FRONT SETTLES NEAR THE OHIO RIVER.
TEMPS...SEVERAL FACTORS SUGGESTIVE THAT FRIDAY COULD BE THE HOTTEST
DAY OF THIS RECENT STRETCH OF HOT DAYS FOR MUCH OF THE FORECAST AREA.
850MB TEMPS RISE TO 20-21C AND COMBINED WITH THE STRONGER W/SW FLOW
WHICH SHOULD ENHANCE BOUNDARY LAYER MIXING AND COMPRESSIONAL HEATING
AHEAD OF THE FRONT...COULD VERY WELL SEE TEMPS MAX OUT AT 94-95 IN
SOME LOCATIONS. MOS GUIDANCE LOOKS FAR TOO COOL AND WILL GENERALLY
BE 2-3 DEGREES WARMER. MOS GUIDANCE WITH HIGHS MAINLY IN THE UPPER
80S LOOKED REASONABLE FOR SATURDAY WITH STORMS AND INCREASED CLOUD
COVERAGE. LOWS WILL REMAIN IN THE 70S TONIGHT AND FRIDAY NIGHT...
FALLING BACK INTO THE 60S SATURDAY NIGHT AS COOLER DRIER AIR EXPANDS
SOUTH BEHIND THE FRONT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 305 AM EDT THU JUL 18 2013
TEMPERATURES WILL NOT BE QUITE AS HOT DURING THE LONG TERM AS THE
UPPER HIGH WILL BE OVER THE WESTERN U.S. AND HEIGHTS LOWER A LITTLE
ACROSS THE GREAT LAKES. A WEAK COLD FRONT WILL STALL ACROSS THE
GREAT LAKES SUNDAY AS HIGH PRESSURE MOVES EAST ACROSS THE GREAT
LAKES. ALL AREAS SHOULD REMAIN DRY UNDER THIS SITUATION SUNDAY.
AFTER SUNDAY WILL MENTION CHANCE POPS FROM LATE SUNDAY NIGHT THROUGH
DAY 7 AS A SERIES OF WEAK DISTURBANCES MOVE EAST ALONG THIS STALLED
FRONT. THERE IS SOME DISCREPANCY ON TIMING OF THESE DISTURBANCES
BETWEEN THE DIFFERENT MODELS. HOWEVER MODEL CONSENSUS SEEMS TO POINT
TOWARDS ONE OF THE MAIN DISTURBANCES MOVING THROUGH AROUND MONDAY
AND ANOTHER ONE EITHER MOVING ACROSS OUR REGION TUESDAY NIGHT OR
WEDNESDAY.
CUT ALL BLEND POPS A LITTLE SUNDAY AND SUNDAY EVENING.
OTHERWISE...I DID NOT MAKE ANY SIGNIFICANT CHANGES TO POPS OR
TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR THE 181500Z TAF ISSUANCE/...
ISSUED AT 1026 AM EDT THU JUL 18 2013
TAF UPDATED TO TWEAK CURRENT CONDITIONS. PREVIOUS DISCUSSION
FOLLOWS...
VISIBILITY RESTRICTIONS POSSIBLE AT KBMG/KHUF/KLAF AFTER 06Z
TONIGHT. OTHERWISE...TAFS WILL BE VFR.
HIGH PRESSURE BOTH SURFACE AND ALOFT WILL CONTINUE ACROSS THE REGION.
EXPECT SCATTERED CU AROUND 4 THOUSAND MOST OF TODAY. PATTERN IS
VERY STAGNANT AND WILL LEAN HEAVILY TOWARDS PERSISTENCE. CU SHOULD
DISSIPATE SHORTLY AFTER SUNSET AND FOG WILL REDEVELOP AGAIN LATE
TONIGHT SIMILAR TO LAST NIGHT. WINDS WILL BE FROM THE WEST AT 5
KNOTS OR LESS TODAY AND LIGHT TONIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....JH
AVIATION...JH/CP
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
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WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
650 AM EDT THU JUL 18 2013
.UPDATE...
AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 346 AM EDT THU JUL 18 2013
HOT AND HUMID WEATHER WILL CONTINUE THROUGH FRIDAY AS THE RIDGE
ALOFT GRADUALLY SHIFTS TO THE SOUTH. A VIGOROUS UPPER LEVEL LOW WILL
TRACK THROUGH EASTERN CANADA WITH A COLD FRONT TRACKING SOUTH INTO
THE REGION ON SATURDAY. THE ARRIVAL AND PASSAGE OF THE FRONT WILL
BRING NUMEROUS SHOWERS AND THUNDERSTORMS TO CENTRAL INDIANA LATE
FRIDAY NIGHT THROUGH SATURDAY EVENING. COOLER DRIER AIR WILL BRIEFLY
BUILD INTO THE REGION ON SUNDAY AS HIGH PRESSURE PASSES THROUGH THE
GREAT LAKES. CHANCES FOR THUNDERSTORMS WILL RETURN BY LATE SUNDAY
NIGHT AND MONDAY AND CONTINUE THROUGH THE MIDDLE OF NEXT WEEK AS THE
FRONTAL BOUNDARY DRIFTS BACK NORTH INTO THE AREA.
&&
.NEAR TERM /TODAY/...
ISSUED AT 346 AM EDT THU JUL 18 2013
ANOTHER MUGGY START EARLY THIS MORNING AS 07Z TEMPS GENERALLY IN THE
MID AND UPPER 70S. CONVECTIVE DEBRIS CLOUDS CONTINUE TO DRIFT INTO
THE SOUTHERN HALF OF THE FORECAST AREA AS A WEAK UPPER WAVE
CURRENTLY TRACKS ACROSS THE TENNESSEE VALLEY.
THE UPPER LEVEL HIGH REMAINS PARKED ACROSS CENTRAL INDIANA WITH MID
LEVEL HEIGHT MAXES STILL AROUND 597DAM. THESE HEIGHTS WILL SLOWLY
FALL THROUGH THE DAY AS THE RIDGE GRADUALLY BUCKLES IN RESPONSE TO A
DEVELOPING STRONG UPPER LOW GETTING ITS ACT TOGETHER ACROSS JAMES
BAY. THE AFOREMENTIONED WEAK WAVE ALOFT OVER THE TENNESSEE VALLEY
WILL DRIFT WEST THROUGH THE DAY AND SHOULD BE LOCATED OVER THE LOWER
OHIO VALLEY BY LATE DAY. SCATTERED CONVECTION ASSOCIATED WITH THIS
FEATURE SHOULD DEVELOP ACROSS KENTUCKY AND TENNESSEE AND MAY EVEN
SEE A FEW STORMS MAKE IT INTO OUR SOUTHERN COUNTIES. THE HRRR LOOKS
TO BE OVERDOING CONVECTIVE DEVELOPMENT IN GENERAL BUT HINTS AT THIS
IDEA AS WELL. CONSIDERING THE NATURE OF THE AIRMASS AND THE
PROXIMITY OF THE UPPER WAVE...ISOLATED POPS ARE WARRANTED ACROSS FAR
SOUTHERN COUNTIES FOR THIS AFTERNOON. FURTHER NORTH DESPITE THE
GRADUALLY LOWERING MID LEVEL HEIGHTS...THE RIDGING ALOFT AND CAP
NEAR 650MB ARE LIKELY TO REMAIN TOO STRONG FOR ANY SUBSTANTIAL
CONVECTIVE DEVELOPMENT. WHILE AN ISOLATED SHOWER CANNOT BE RULED
OUT...COVERAGE LIKELY TO BE SO LOW TO PRECLUDE ANY MENTION IN THE
FORECAST AT THIS TIME.
TEMPS...LOW LEVEL THERMALS WILL BE SIMILAR TO WEDNESDAY WITH 850MB
TEMPS RISING TO AROUND 19-20C. LIKEWISE EXPECT HIGH TEMPS TO BE
SIMILAR TO WEDNESDAY AS WELL...REACHING THE 92-94 DEGREE RANGE FOR
MUCH OF THE FORECAST AREA. GENERALLY GOING A DEGREE OR TWO ABOVE
MOS. MAX HEAT INDICES WILL RISE TO AROUND 100 DEGREES AGAIN THIS
AFTERNOON...AND MAY TOP OUT JUST A TOUCH WARMER THAN WEDNESDAY AS
SLIGHTLY DEEPER MOISTURE IS PULLED NORTH INTO THE REGION. HAVE NO
PLANS TO INTRODUCE A HEAT ADVISORY AS THESE VALUES REMAINS BELOW
CRITERIA. WILL CONTINUE WITH THE SPS.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 346 AM EDT THU JUL 18 2013
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES AND TEMPS AS A COLD
FRONT DROPS SOUTH THROUGH THE REGION SATURDAY. MODELS GENERALLY IN
VERY GOOD AGREEMENT ON MAIN FEATURES THROUGHOUT THE SHORT TERM.
RIDGING ALOFT WILL CONTINUE TO SINK SOUTH AND FLATTEN AS THE DEEP
UPPER LOW DIVES ACROSS NORTHERN ONTARIO...THEN PINWHEELS INTO THE
CANADIAN MARITIMES BY SUNDAY MORNING. ROBUST CONVECTIVE DEVELOPMENT
WILL TAKE PLACE TONIGHT OVER THE UPPER MISSISSIPPI VALLEY AND
NORTHERN GREAT LAKES IN PROXIMITY TO THE COLD FRONT. THIS FRONT WILL
SINK SOUTH AND SHOULD BE LOCATED ACROSS THE WESTERN GREAT LAKES BY
FRIDAY AFTERNOON. THE FLATTENING OF THE RIDGE AND APPROACH OF THE
COLD FRONT WILL ENCOURAGE A W/SW FLOW THROUGH THE LOWER LEVELS ON
FRIDAY...WITH POTENTIAL FOR SOME GUSTS TO NEAR 20-25KTS OVER
NORTHERN COUNTIES BY AFTERNOON AS A LOW LEVEL JET ACCOMPANIES THE
BOUNDARY THROUGH THE GREAT LAKES. WILL MAINTAIN LOW CHANCE POPS FOR
ISOLATED CONVECTIVE DEVELOPMENT FRIDAY AFTERNOON...BUT ANTICIPATE IT
WILL BE MORE FOCUSED OVER THE SOUTHERN HALF OF THE FORECAST AREA
WHERE DEEPER MOISTURE WILL RESIDE. THE W/SW FLOW WILL DRAW A SLUG OF
DRIER AIR ALOFT INTO THE LOWER GREAT LAKES IMMEDIATELY AHEAD OF THE
FRONT THAT WILL GRADUALLY BECOME SQUEEZED BY MOISTURE ADVECTING NORTH
AROUND THE BACK SIDE OF THE BERMUDA HIGH AND MOISTURE POOLING ALONG
THE BOUNDARY. THIS MAY LIMIT CONVECTIVE DEVELOPMENT OVER NORTHERN
COUNTIES FOR MUCH OF THE DAY.
FOCUS WILL SHIFT TO THE N/NW OF THE REGION BY LATE FRIDAY AFTERNOON
AS CONVECTION IS LIKELY TO DEVELOP IN THE VICINITY OF THE BOUNDARY
AND QUICKLY BECOME SEVERE AS BL SHEAR VALUES ARE ENHANCED AND
AIRMASS WILL BE MODERATELY UNSTABLE. STORMS ARE LIKELY TO ORGANIZE
INTO A MESOSCALE CONVECTIVE COMPLEX BY FRIDAY EVENING WITH
THERMODYNAMIC PROFILES SUGGESTING THE POTENTIAL FOR A SIGNIFICANT
DAMAGING WIND THREAT AS THE STORMS MOVE ACROSS THE LOWER GREAT
LAKES. THIS CONVECTION SHOULD LARGELY REMAIN TO THE NORTH OF THE
FORECAST AREA THROUGH THE EVENING...WITH PRECIP CHANCES RISING AFTER
MIDNIGHT AS THE TAIL END OF THE COMPLEX SAGS SOUTH INTO THE REGION
WITH THE COLD FRONT. AT THIS POINT...THERE IS GREATER UNCERTAINTY AS
TO THE POTENTIAL FOR CONVECTION TO MAINTAIN ITS INTENSITY OVER THE
FORECAST AREA LATE FRIDAY NIGHT. THE CORE OF THE COMPLEX IS EXPECTED
TO TRACK ACROSS THE LOWER GREAT LAKES IN CLOSER PROXIMITY TO THE
DEEPER FORCING ALOFT AND THE LOCATION OF THE LOW LEVEL JET. THE
COMPLEX IS LIKELY TO DROP A WELL DEFINED COLD POOL AND THERE IS A
POSSIBILITY THAT THIS COULD WORK INTO NORTHERN PORTIONS OF THE
FORECAST AREA BEFORE WEAKENING. AT THIS POINT...ANTICIPATE A
WEAKENING LINE OF STORMS IMPACTING THE FORECAST AREA LATE FRIDAY
NIGHT WITH THE POTENTIAL FOR STORMS TO PRODUCE DAMAGING WINDS.
THE FRONT WILL SLOW DOWN ITS FORWARD PROGRESS AS IT RUNS INTO THE
SUPPRESSED RIDGE TO OUR SOUTH. BOUNDARY LIKELY TO TAKE ALL DAY
SATURDAY AND LIKELY A PORTION OF SATURDAY NIGHT TO MOVE ACROSS THE
FORECAST AREA. LEFTOVER CONVECTION FROM FRIDAY NIGHT MAY BE ONGOING
IN A WEAKENED STATE SATURDAY MORNING...BUT EXPECT RENEWED
DEVELOPMENT THROUGHOUT THE DAY. PRECIP WATER VALUES NEAR 2
INCHES...LOW LEVEL CONVERGENCE IN VICINITY OF THE FRONT AND MODEST
INSTABILITY WILL BE THE MAIN CATALYSTS FOR CONVECTIVE DEVELOPMENT
AND INTENSITY AS DEEPER FORCING ALOFT WILL BE FOCUSED FURTHER TO THE
NORTHEAST OVER THE EASTERN GREAT LAKES AND INTO NEW ENGLAND. WHILE
STORMS WILL HAVE THE POTENTIAL TO PRODUCE DAMAGING WINDS...NOT
EXPECTING A WIDESPREAD SEVERE THREAT IN THE ABSENCE OF DEEPER SHEAR
AND BETTER FORCING ALOFT. POTENTIAL FOR HEAVY RAINFALL AND LOCALIZED
FLOODING WITH THE HIGH PWATS. WILL CARRY HIGH CHANCE/LIKELY POPS
SATURDAY...WITH PRECIP CHANCES ENDING LATE SATURDAY NIGHT AS THE
FRONT SETTLES NEAR THE OHIO RIVER.
TEMPS...SEVERAL FACTORS SUGGESTIVE THAT FRIDAY COULD BE THE HOTTEST
DAY OF THIS RECENT STRETCH OF HOT DAYS FOR MUCH OF THE FORECAST AREA.
850MB TEMPS RISE TO 20-21C AND COMBINED WITH THE STRONGER W/SW FLOW
WHICH SHOULD ENHANCE BOUNDARY LAYER MIXING AND COMPRESSIONAL HEATING
AHEAD OF THE FRONT...COULD VERY WELL SEE TEMPS MAX OUT AT 94-95 IN
SOME LOCATIONS. MOS GUIDANCE LOOKS FAR TOO COOL AND WILL GENERALLY
BE 2-3 DEGREES WARMER. MOS GUIDANCE WITH HIGHS MAINLY IN THE UPPER
80S LOOKED REASONABLE FOR SATURDAY WITH STORMS AND INCREASED CLOUD
COVERAGE. LOWS WILL REMAIN IN THE 70S TONIGHT AND FRIDAY NIGHT...
FALLING BACK INTO THE 60S SATURDAY NIGHT AS COOLER DRIER AIR EXPANDS
SOUTH BEHIND THE FRONT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 305 AM EDT THU JUL 18 2013
TEMPERATURES WILL NOT BE QUITE AS HOT DURING THE LONG TERM AS THE
UPPER HIGH WILL BE OVER THE WESTERN U.S. AND HEIGHTS LOWER A LITTLE
ACROSS THE GREAT LAKES. A WEAK COLD FRONT WILL STALL ACROSS THE
GREAT LAKES SUNDAY AS HIGH PRESSURE MOVES EAST ACROSS THE GREAT
LAKES. ALL AREAS SHOULD REMAIN DRY UNDER THIS SITUATION SUNDAY.
AFTER SUNDAY WILL MENTION CHANCE POPS FROM LATE SUNDAY NIGHT THROUGH
DAY 7 AS A SERIES OF WEAK DISTURBANCES MOVE EAST ALONG THIS STALLED
FRONT. THERE IS SOME DISCREPANCY ON TIMING OF THESE DISTURBANCES
BETWEEN THE DIFFERENT MODELS. HOWEVER MODEL CONSENSUS SEEMS TO POINT
TOWARDS ONE OF THE MAIN DISTURBANCES MOVING THROUGH AROUND MONDAY
AND ANOTHER ONE EITHER MOVING ACROSS OUR REGION TUESDAY NIGHT OR
WEDNESDAY.
CUT ALL BLEND POPS A LITTLE SUNDAY AND SUNDAY EVENING.
OTHERWISE...I DID NOT MAKE ANY SIGNIFICANT CHANGES TO POPS OR
TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR THE 181200Z TAF ISSUANCE/...
ISSUED AT 650 AM EDT THU JUL 18 2013
VISIBILITY RESTRICTIONS POSSIBLE AT KBMG/KHUF/KLAF FOR THE 1ST HOUR
AND AGAIN AFTER 06Z TONIGHT. OTHERWISE...TAFS WILL BE VFR.
HIGH PRESSURE BOTH SURFACE AND ALOFT WILL CONTINUE ACROSS THE REGION.
DAYTIME HEATING SHOULD CLEAR OUT ANY FOG NEXT HOUR OR TWO. AFTER THAT
EXPECT SCATTERED CU AROUND 4 THOUSAND MOST OF TODAY. PATTERN IS VERY
STAGNANT AND WILL LEAN HEAVILY TOWARDS PERSISTENCE. CU SHOULD DISSIPATE
SHORTLY AFTER SUNSET AND FOG WILL REDEVELOP AGAIN LATE TONIGHT SIMILAR
TO LAST NIGHT. WINDS WILL BE FROM THE WEST AT 5 KNOTS OR LESS TODAY AND
LIGHT TONIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....JH
AVIATION...JH
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS JACKSON KY
221 PM EDT THU JUL 18 2013
.UPDATE...
ISSUED AT 221 PM EDT THU JUL 18 2013
UPDATED FORECAST GRIDS BASED ON LATEST TRENDS. NO APPRECIABLE CHANGE
OCCURRED TO THE OVERALL FORECAST.
UPDATE ISSUED AT 1105 AM EDT THU JUL 18 2013
SHOWERS/THUNDERSTORMS SO FAR HAVE BEEN TO OUR WEST...AND HAVE UPDATED TO
DELAY THEIR DEVELOPMENT A BIT TODAY. WITH BOTH GFS AND NEW 12Z NAM
SHOWING BEST SHOT AT PRECIP OVER THE HIGHER TERRAIN IN OUR SE THIS
AFTERNOON...HAVE LEFT THE INHERITED 12 HOUR POPS IN PLACE WITH THE
HIGHER VALUES IN THE SE. HOWEVER...THE HRRR IS ALSO SHOWING
DEVELOPMENT OVER OUR WESTERN COUNTIES TODAY. DO NOT HAVE A LOT OF
CONFIDENCE IN THE CONVECTIVE EVOLUTION TODAY. HAVE ALSO TOUCHED UP
OTHER GRIDS BASED ON LATEST OBS. ALL IN ALL...MADE LITTLE CHANGE TO
THE OVERALL AFTERNOON FORECAST.
UPDATE ISSUED AT 710 AM EDT THU JUL 18 2013
FRESHENED UP THE HOURLY TEMPERATURES...DEW POINTS...AND SKY COVER
ACCORDING TO THE LATEST TRENDS IN OBSERVATIONS. OTHERWISE...THE
FORECAST REMAINS ON TRACK.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 355 AM EDT THU JUL 18 2013
THE MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM...GRADUALLY
WEAKENING AND SHIFTING THE OHIO VALLEY UPPER LEVEL RIDGE SOUTHEAST
WITH TIME...AS PASSING UPPER LEVEL DISTURBANCES WITHIN THE NORTHERN
STREAM TRAVERSE THE U.S./CANDAIAN BORDER.
ONE MORE DAY OF HEAT INDICES APPROACHING THE 100 DEGREE MARK IS
EXPECTED...AS HIGHS TOP OUT IN THE LOWER 90S...WHILE DEW POINTS HANG IN
THE LOWER TO MID 70S. CONVECTION WILL THREATEN ONCE AGAIN TODAY AS
THE RIDGE GRADUALLY BREAKS DOWN...ALTHOUGH INSTABILITY LOOKS TO BE
SLIGHTLY WEAKER TODAY COMPARED TO YESTERDAY. THE BLENDED MODEL
GUIDANCE YIELDS SCATTERED COVERAGE TODAY...WITH HIGHER POPS IN THE
SOUTHEAST. THIS SEEMED TO WORK WELL YESTERDAY...SO WILL GO WITH A
SIMILAR SCENARIO...ALTHOUGH WITH WEAK STORM MOTIONS...OUTFLOW
BOUNDARIES COULD SURGE FORWARD FROM ANY DIRECTION AND COULD SPARK NEW
CONVECTION. LOCALLY HEAVY RAINFALL...GUSTY WINDS...AND SMALL HAIL
WITH ACCOMPANY THE STRONGER STORMS.
CONVECTION WILL GRADUALLY DIMINISH THIS EVENING WITH THE LOSS OF
HEATING...AS LOWS ONCE AGAIN ONLY DROP DOWN TO AROUND 70. BY
FRIDAY...THE UPPER LEVEL RIDGE WILL HAVE SHIFTED TO OFF THE
SOUTHEAST COAST. THIS WILL ALLOW FOR MORE CLOUD COVER AND BETTER
CONVECTIVE AREAL COVERAGE ACROSS THE AREA DURING THE AFTERNOON.
AGAIN...LOCALLY HEAVY RAINFALL...GUSTY WINDS...AN SMALL HAIL WILL
ACCOMPANY THE STRONGER STORMS. HEAT INDICES SHOULD BE SLIGHTLY LESS
ON FRIDAY...GENERALLY IN THE MID 90S.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 355 AM EDT THU JUL 18 2013
THERE CONTINUES TO BE GOOD MODEL AGREEMENT THAT THE UPPER LEVEL
RIDGE WILL BE IN THE PROCESS OF BREAKING DOWN AT THE BEGINNING OF
THE LONG TERM FORECAST PERIOD. THIS WEEKEND...A STRONG UPPER LEVEL
LOW WILL BE SWINGING THROUGH EASTERN CANADA...SOLIDIFYING A BROAD
TROUGH ACROSS THE GREAT LAKES AND OHIO VALLEY REGIONS...WHICH SHOULD
THEN PERSIST INTO THE MIDDLE OF NEXT WEEK.
FRIDAY NIGHT AND SATURDAY...A WEAK COLD FRONT WILL BE
APPROACHING FROM THE NORTH. IT APPEARS THE FRONT WILL MAKE ITS WAY
INTO EASTERN KY SUNDAY...BUT WILL LIKELY LINGER ACROSS KY OR
NORTHERN TN INTO THE EARLY TO MIDDLE PART OF NEXT WEEK. WITH
APPROACH OF THE FRONT...THE THREAT FOR MORE ORGANIZED CONVECTION
WILL INCREASE LATE SATURDAY INTO SATURDAY EVENING AND NIGHT AND
LINGER INTO SUNDAY. THE STRONG WINDS ALOFT AND BEST DYNAMICS FROM
THIS SYSTEM WILL PASS BY TO OUR NORTH AND NORTHEAST...SO THE RISK OF
SEVERE THUNDERSTORMS SHOULD REMAIN NORTH OF THE OH RIVER...ALTHOUGH
A FEW STRONG STORMS ARE POSSIBLE SAT AFTERNOON AND EVENING ACROSS
EASTERN KY. ANY STORMS THAT DEVELOP WILL BE RATHER SLOW MOVING AND
WITH THE FRONT STALLING OUT OVER OR NEAR KY...SOME LOCALLY HEAVY
RAIN IS POSSIBLE.
WHILE OVERALL RAIN PROBABILITIES SHOULD DECREASE EARLY NEXT WEEK...A
SERIES OF HARD TO TIME SHORT WAVE TROUGHS MOVING ACROSS THE OH
VALLEY IN THE MEAN FLOW WILL CONTINUE THE THREAT FOR ROUNDS OF
SHOWERS AND THUNDERSTORMS. CONFIDENCE IN TIMING OF THESE CHANCES IS
RATHER LOW...AND A DIURNAL FLAVOR WAS USED IN THE POPS FOR MOST OF
THE PERIOD.
TEMPERATURES SHOULD REMAIN AT OR BELOW NORMAL THROUGH THE PERIOD FOR
DAYTIME HIGHS. HOWEVER...A MOIST AIR MASS WILL REMAIN WITH DEW POINTS
IN THE UPPER 60S TO AROUND 70 SO OVERNIGHT LOWS SHOULD AVERAGE A FEW
DEGREES ABOVE NORMAL THROUGH THE PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 133 PM EDT THU JUL 18 2013
SCATTERED SHOWERS/THUNDERSTORMS WILL OCCUR THIS AFTERNOON.
LOCALIZED IFR WILL OCCUR IN THE THUNDERSTORMS AND HEAVIER SHOWERS.
THE EXTENT OF COVERAGE IS UNCERTAIN...AND THIS WILL ALSO PLAY A ROLE
IN WEATHER FOR TONIGHT. FOG IS EXPECTED TONIGHT...ESPECIALLY IN
VALLEYS. AREAS WHICH RECEIVE RAIN LATE IN THE DAY WILL BE
PARTICULARLY SUSCEPTIBLE TO FOG TONIGHT. HOWEVER...WITH COVERAGE OF
PRECIP TODAY IN QUESTION...WILL BE CONSERVATIVE IN FORECASTING FOG AT
TAF SITES FOR TONIGHT. FOG WILL DISSIPATE BY AROUND 13Z ON FRIDAY.
OUTSIDE OF LOCALIZED SHOWERS/THUNDERSTORMS AND NIGHT TIME FOG...VFR
WITH LIGHT WINDS IS FORECAST.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...GEOGERIAN
LONG TERM...SBH/JP
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS JACKSON KY
133 PM EDT THU JUL 18 2013
.UPDATE...
ISSUED AT 1105 AM EDT THU JUL 18 2013
SHOWERS/THUNDERSTORMS SO FAR HAVE BEEN TO OUR WEST...AND HAVE UPDATED TO
DELAY THEIR DEVELOPMENT A BIT TODAY. WITH BOTH GFS AND NEW 12Z NAM
SHOWING BEST SHOT AT PRECIP OVER THE HIGHER TERRAIN IN OUR SE THIS
AFTERNOON...HAVE LEFT THE INHERITED 12 HOUR POPS IN PLACE WITH THE
HIGHER VALUES IN THE SE. HOWEVER...THE HRRR IS ALSO SHOWING
DEVELOPMENT OVER OUR WESTERN COUNTIES TODAY. DO NOT HAVE A LOT OF
CONFIDENCE IN THE CONVECTIVE EVOLUTION TODAY. HAVE ALSO TOUCHED UP
OTHER GRIDS BASED ON LATEST OBS. ALL IN ALL...MADE LITTLE CHANGE TO
THE OVERALL AFTERNOON FORECAST.
UPDATE ISSUED AT 710 AM EDT THU JUL 18 2013
FRESHENED UP THE HOURLY TEMPERATURES...DEW POINTS...AND SKY COVER
ACCORDING TO THE LATEST TRENDS IN OBSERVATIONS. OTHERWISE...THE
FORECAST REMAINS ON TRACK.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 355 AM EDT THU JUL 18 2013
THE MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM...GRADUALLY
WEAKENING AND SHIFTING THE OHIO VALLEY UPPER LEVEL RIDGE SOUTHEAST
WITH TIME...AS PASSING UPPER LEVEL DISTURBANCES WITHIN THE NORTHERN
STREAM TRAVERSE THE U.S./CANDAIAN BORDER.
ONE MORE DAY OF HEAT INDICES APPROACHING THE 100 DEGREE MARK IS
EXPECTED...AS HIGHS TOP OUT IN THE LOWER 90S...WHILE DEW POINTS HANG IN
THE LOWER TO MID 70S. CONVECTION WILL THREATEN ONCE AGAIN TODAY AS
THE RIDGE GRADUALLY BREAKS DOWN...ALTHOUGH INSTABILITY LOOKS TO BE
SLIGHTLY WEAKER TODAY COMPARED TO YESTERDAY. THE BLENDED MODEL
GUIDANCE YIELDS SCATTERED COVERAGE TODAY...WITH HIGHER POPS IN THE
SOUTHEAST. THIS SEEMED TO WORK WELL YESTERDAY...SO WILL GO WITH A
SIMILAR SCENARIO...ALTHOUGH WITH WEAK STORM MOTIONS...OUTFLOW
BOUNDARIES COULD SURGE FORWARD FROM ANY DIRECTION AND COULD SPARK NEW
CONVECTION. LOCALLY HEAVY RAINFALL...GUSTY WINDS...AND SMALL HAIL
WITH ACCOMPANY THE STRONGER STORMS.
CONVECTION WILL GRADUALLY DIMINISH THIS EVENING WITH THE LOSS OF
HEATING...AS LOWS ONCE AGAIN ONLY DROP DOWN TO AROUND 70. BY
FRIDAY...THE UPPER LEVEL RIDGE WILL HAVE SHIFTED TO OFF THE
SOUTHEAST COAST. THIS WILL ALLOW FOR MORE CLOUD COVER AND BETTER
CONVECTIVE AREAL COVERAGE ACROSS THE AREA DURING THE AFTERNOON.
AGAIN...LOCALLY HEAVY RAINFALL...GUSTY WINDS...AN SMALL HAIL WILL
ACCOMPANY THE STRONGER STORMS. HEAT INDICES SHOULD BE SLIGHTLY LESS
ON FRIDAY...GENERALLY IN THE MID 90S.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 355 AM EDT THU JUL 18 2013
THERE CONTINUES TO BE GOOD MODEL AGREEMENT THAT THE UPPER LEVEL
RIDGE WILL BE IN THE PROCESS OF BREAKING DOWN AT THE BEGINNING OF
THE LONG TERM FORECAST PERIOD. THIS WEEKEND...A STRONG UPPER LEVEL
LOW WILL BE SWINGING THROUGH EASTERN CANADA...SOLIDIFYING A BROAD
TROUGH ACROSS THE GREAT LAKES AND OHIO VALLEY REGIONS...WHICH SHOULD
THEN PERSIST INTO THE MIDDLE OF NEXT WEEK.
FRIDAY NIGHT AND SATURDAY...A WEAK COLD FRONT WILL BE
APPROACHING FROM THE NORTH. IT APPEARS THE FRONT WILL MAKE ITS WAY
INTO EASTERN KY SUNDAY...BUT WILL LIKELY LINGER ACROSS KY OR
NORTHERN TN INTO THE EARLY TO MIDDLE PART OF NEXT WEEK. WITH
APPROACH OF THE FRONT...THE THREAT FOR MORE ORGANIZED CONVECTION
WILL INCREASE LATE SATURDAY INTO SATURDAY EVENING AND NIGHT AND
LINGER INTO SUNDAY. THE STRONG WINDS ALOFT AND BEST DYNAMICS FROM
THIS SYSTEM WILL PASS BY TO OUR NORTH AND NORTHEAST...SO THE RISK OF
SEVERE THUNDERSTORMS SHOULD REMAIN NORTH OF THE OH RIVER...ALTHOUGH
A FEW STRONG STORMS ARE POSSIBLE SAT AFTERNOON AND EVENING ACROSS
EASTERN KY. ANY STORMS THAT DEVELOP WILL BE RATHER SLOW MOVING AND
WITH THE FRONT STALLING OUT OVER OR NEAR KY...SOME LOCALLY HEAVY
RAIN IS POSSIBLE.
WHILE OVERALL RAIN PROBABILITIES SHOULD DECREASE EARLY NEXT WEEK...A
SERIES OF HARD TO TIME SHORT WAVE TROUGHS MOVING ACROSS THE OH
VALLEY IN THE MEAN FLOW WILL CONTINUE THE THREAT FOR ROUNDS OF
SHOWERS AND THUNDERSTORMS. CONFIDENCE IN TIMING OF THESE CHANCES IS
RATHER LOW...AND A DIURNAL FLAVOR WAS USED IN THE POPS FOR MOST OF
THE PERIOD.
TEMPERATURES SHOULD REMAIN AT OR BELOW NORMAL THROUGH THE PERIOD FOR
DAYTIME HIGHS. HOWEVER...A MOIST AIR MASS WILL REMAIN WITH DEW POINTS
IN THE UPPER 60S TO AROUND 70 SO OVERNIGHT LOWS SHOULD AVERAGE A FEW
DEGREES ABOVE NORMAL THROUGH THE PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 133 PM EDT THU JUL 18 2013
SCATTERED SHOWERS/THUNDERSTORMS WILL OCCUR THIS AFTERNOON.
LOCALIZED IFR WILL OCCUR IN THE THUNDERSTORMS AND HEAVIER SHOWERS.
THE EXTENT OF COVERAGE IS UNCERTAIN...AND THIS WILL ALSO PLAY A ROLE
IN WEATHER FOR TONIGHT. FOG IS EXPECTED TONIGHT...ESPECIALLY IN
VALLEYS. AREAS WHICH RECEIVE RAIN LATE IN THE DAY WILL BE
PARTICULARLY SUSCEPTIBLE TO FOG TONIGHT. HOWEVER...WITH COVERAGE OF
PRECIP TODAY IN QUESTION...WILL BE CONSERVATIVE IN FORECASTING FOG AT
TAF SITES FOR TONIGHT. FOG WILL DISSIPATE BY AROUND 13Z ON FRIDAY.
OUTSIDE OF LOCALIZED SHOWERS/THUNDERSTORMS AND NIGHT TIME FOG...VFR
WITH LIGHT WINDS IS FORECAST.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...GEOGERIAN
LONG TERM...SBH/JP
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS JACKSON KY
1105 AM EDT THU JUL 18 2013
.UPDATE...
ISSUED AT 1105 AM EDT THU JUL 18 2013
SHOWERS/THUNDERSTORMS SO FAR HAVE BEEN TO OUR WEST...AND HAVE UPDATED TO
DELAY THEIR DEVELOPMENT A BIT TODAY. WITH BOTH GFS AND NEW 12Z NAM
SHOWING BEST SHOT AT PRECIP OVER THE HIGHER TERRAIN IN OUR SE THIS
AFTERNOON...HAVE LEFT THE INHERITED 12 HOUR POPS IN PLACE WITH THE
HIGHER VALUES IN THE SE. HOWEVER...THE HRRR IS ALSO SHOWING
DEVELOPMENT OVER OUR WESTERN COUNTIES TODAY. DO NOT HAVE A LOT OF
CONFIDENCE IN THE CONVECTIVE EVOLUTION TODAY. HAVE ALSO TOUCHED UP
OTHER GRIDS BASED ON LATEST OBS. ALL IN ALL...MADE LITTLE CHANGE TO
THE OVERALL AFTERNOON FORECAST.
UPDATE ISSUED AT 710 AM EDT THU JUL 18 2013
FRESHENED UP THE HOURLY TEMPERATURES...DEW POINTS...AND SKY COVER
ACCORDING TO THE LATEST TRENDS IN OBSERVATIONS. OTHERWISE...THE
FORECAST REMAINS ON TRACK.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 355 AM EDT THU JUL 18 2013
THE MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM...GRADUALLY
WEAKENING AND SHIFTING THE OHIO VALLEY UPPER LEVEL RIDGE SOUTHEAST
WITH TIME...AS PASSING UPPER LEVEL DISTURBANCES WITHIN THE NORTHERN
STREAM TRAVERSE THE U.S./CANDAIAN BORDER.
ONE MORE DAY OF HEAT INDICES APPROACHING THE 100 DEGREE MARK IS
EXPECTED...AS HIGHS TOP OUT IN THE LOWER 90S...WHILE DEW POINTS HANG IN
THE LOWER TO MID 70S. CONVECTION WILL THREATEN ONCE AGAIN TODAY AS
THE RIDGE GRADUALLY BREAKS DOWN...ALTHOUGH INSTABILITY LOOKS TO BE
SLIGHTLY WEAKER TODAY COMPARED TO YESTERDAY. THE BLENDED MODEL
GUIDANCE YIELDS SCATTERED COVERAGE TODAY...WITH HIGHER POPS IN THE
SOUTHEAST. THIS SEEMED TO WORK WELL YESTERDAY...SO WILL GO WITH A
SIMILAR SCENARIO...ALTHOUGH WITH WEAK STORM MOTIONS...OUTFLOW
BOUNDARIES COULD SURGE FORWARD FROM ANY DIRECTION AND COULD SPARK NEW
CONVECTION. LOCALLY HEAVY RAINFALL...GUSTY WINDS...AND SMALL HAIL
WITH ACCOMPANY THE STRONGER STORMS.
CONVECTION WILL GRADUALLY DIMINISH THIS EVENING WITH THE LOSS OF
HEATING...AS LOWS ONCE AGAIN ONLY DROP DOWN TO AROUND 70. BY
FRIDAY...THE UPPER LEVEL RIDGE WILL HAVE SHIFTED TO OFF THE
SOUTHEAST COAST. THIS WILL ALLOW FOR MORE CLOUD COVER AND BETTER
CONVECTIVE AREAL COVERAGE ACROSS THE AREA DURING THE AFTERNOON.
AGAIN...LOCALLY HEAVY RAINFALL...GUSTY WINDS...AN SMALL HAIL WILL
ACCOMPANY THE STRONGER STORMS. HEAT INDICES SHOULD BE SLIGHTLY LESS
ON FRIDAY...GENERALLY IN THE MID 90S.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 355 AM EDT THU JUL 18 2013
THERE CONTINUES TO BE GOOD MODEL AGREEMENT THAT THE UPPER LEVEL
RIDGE WILL BE IN THE PROCESS OF BREAKING DOWN AT THE BEGINNING OF
THE LONG TERM FORECAST PERIOD. THIS WEEKEND...A STRONG UPPER LEVEL
LOW WILL BE SWINGING THROUGH EASTERN CANADA...SOLIDIFYING A BROAD
TROUGH ACROSS THE GREAT LAKES AND OHIO VALLEY REGIONS...WHICH SHOULD
THEN PERSIST INTO THE MIDDLE OF NEXT WEEK.
FRIDAY NIGHT AND SATURDAY...A WEAK COLD FRONT WILL BE
APPROACHING FROM THE NORTH. IT APPEARS THE FRONT WILL MAKE ITS WAY
INTO EASTERN KY SUNDAY...BUT WILL LIKELY LINGER ACROSS KY OR
NORTHERN TN INTO THE EARLY TO MIDDLE PART OF NEXT WEEK. WITH
APPROACH OF THE FRONT...THE THREAT FOR MORE ORGANIZED CONVECTION
WILL INCREASE LATE SATURDAY INTO SATURDAY EVENING AND NIGHT AND
LINGER INTO SUNDAY. THE STRONG WINDS ALOFT AND BEST DYNAMICS FROM
THIS SYSTEM WILL PASS BY TO OUR NORTH AND NORTHEAST...SO THE RISK OF
SEVERE THUNDERSTORMS SHOULD REMAIN NORTH OF THE OH RIVER...ALTHOUGH
A FEW STRONG STORMS ARE POSSIBLE SAT AFTERNOON AND EVENING ACROSS
EASTERN KY. ANY STORMS THAT DEVELOP WILL BE RATHER SLOW MOVING AND
WITH THE FRONT STALLING OUT OVER OR NEAR KY...SOME LOCALLY HEAVY
RAIN IS POSSIBLE.
WHILE OVERALL RAIN PROBABILITIES SHOULD DECREASE EARLY NEXT WEEK...A
SERIES OF HARD TO TIME SHORT WAVE TROUGHS MOVING ACROSS THE OH
VALLEY IN THE MEAN FLOW WILL CONTINUE THE THREAT FOR ROUNDS OF
SHOWERS AND THUNDERSTORMS. CONFIDENCE IN TIMING OF THESE CHANCES IS
RATHER LOW...AND A DIURNAL FLAVOR WAS USED IN THE POPS FOR MOST OF
THE PERIOD.
TEMPERATURES SHOULD REMAIN AT OR BELOW NORMAL THROUGH THE PERIOD FOR
DAYTIME HIGHS. HOWEVER...A MOIST AIR MASS WILL REMAIN WITH DEW POINTS
IN THE UPPER 60S TO AROUND 70 SO OVERNIGHT LOWS SHOULD AVERAGE A FEW
DEGREES ABOVE NORMAL THROUGH THE PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 710 AM EDT THU JUL 18 2013
THE FOG WILL BURN OFF THROUGH 13Z...WITH SCATTERED CONVECTION
THREATENING ONCE AGAIN FROM 15Z ONWARD. WILL CARRY A VCTS AT ALL
SITES THROUGH ABOUT 5Z...BEFORE MVFR OR WORSE FOG SETS UP ONCE AGAIN.
WINDS WILL REMAIN LIGHT AND VARIABLE THROUGH THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...GEOGERIAN
LONG TERM...SBH/JP
AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION
NWS GRAY ME
617 PM EDT THU JUL 18 2013
.SYNOPSIS...
VERY HOT AND HUMID AIR MOVES IN FOR FRIDAY INTO SATURDAY. A COLD
FRONT WILL WILL CROSS THE REGION SATURDAY...SETTING OFF SHOWERS
AND THUNDERSTORMS...AND SOME OF THOSE STORMS COULD BE SEVERE.
COOLER AND LESS HUMID HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT
SUNDAY THOUGH TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
WILL UPDATE TO INPUT LATEST OBSERVED DATA. HAVE INCREASED THE
CHANCE OF SHOWERS AND THUNDERSTORMS THIS EVENING BASED ON THE
LATEST RADAR. WILL MENTION GUSTY WINDS AND HEAVY RAIN POSSIBLE
WITH SOME THUNDERSTORMS THIS EVENING.
PREVIOUS DISCUSSION...
RELIED HEAVILY ON THE HRRR MODEL FOR THE FORECAST TONIGHT AS THIS
MODEL HAS HANDLED THINGS VERY WELL THE PAST FEW DAYS AND SEEMS TO
BE DOING SO ONCE AGAIN TODAY. CONVECTION HAS FIRED ON THE SEA
BREEZE BOUNDARY IN MAINE... WITH ACTIVITY TENDING TO FALL APART
AFTER IT ADVECTS INTO THE COOLER MARINE AIR. ADDITIONAL ISOLATED
STORMS HAVE DEVELOPED OVER THE HIGHER TERRAIN IN NEW HAMPSHIRE. A
LARGER AREA OF STORMS DEVELOPED OVER THE ADIRONDACKS OF UPSTATE
NEW YORK AND WILL CONTINUE TO PUSH EASTWARD THROUGH VERMONT AND
INTO NEW HAMPSHIRE THIS AFTERNOON. WIND SHEAR IS SUFFICIENT FOR
SUPERCELLS... AND ALREADY A FEW HAVE BEEN OBSERVED. DAMAGING WINDS
AND HAIL WOULD BE THE THREATS FROM STORMS TODAY... ALTHOUGH HEAVY
RAIN WILL ALSO OCCUR. MODERATE STORM MOTIONS SHOULD LIMIT THE
FLASH FLOODING THREAT. EXPECT MOST OF THE ACTIVITY THIS EVENING TO
DIE DOWN AND MOVE OFF TO THE EAST BY AROUND MIDNIGHT. TEMPERATURES
TONIGHT WILL BE WARM... WITH LOWS IN THE UPPER 60S AND LOW 70S.
FOG WILL BE POSSIBLE IN THE CONNECTICUT RIVER VALLEY.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
HOT AND HUMID AIR OVER THE MID ATLANTIC STATES TODAY... EVIDENCED
BY A BROAD AREA OF +20 C TEMPERATURES AT 850 MB... WILL BE
ADVECTED NORTHEAST AND INTO NEW ENGLAND ON FRIDAY. GFS AND NAM IN
GOOD AGREEMENT ON 850 MB TEMPERATURES OF +21 C BY FRIDAY AFTERNOON
OVER THE SOUTHERN HALF OF THE FORECAST AREA. IN ADDITION...
SOUTHWEST FLOW WILL TRANSPORT HIGH DEW POINTS INTO THE AREA.
EXPECT THE DAY TO START OFF WITH LOW 70S DEW POINTS OVER MUCH OF
THE REGION. BUT A SURFACE TROUGH WILL PUSH EASTWARD ACROSS THE
AREA... SHIFTING WINDS FROM THE SOUTH TO THE WEST-SOUTHWEST. THIS
WEST TO SOUTHWEST WIND WILL HAVE A SIGNIFICANT DOWNSLOPING
COMPONENT TO IT... ALLOWING FOR GREATER MIXING. THIS MEANS THREE
THINGS... HIGHER TEMPERATURES... LOWER DEW POINTS... AND GREATER
WIND SPEEDS. AFTERNOON SOUNDINGS INDICATE THAT AS PEAK HEATING
OCCURS... DEW POINTS WILL FALL INTO THE MID 60S BEHIND THE SURFACE
TROUGH. WITH DOWNSLOPING CONDITIONS... THE HOTTEST TEMPERATURES
WILL OCCUR AT LOWER ELEVATIONS WHICH IN THIS CASE MEANS THE COAST.
IT DOES NOT LOOK LIKE THE SEA BREEZE WILL BE MUCH HELP OVER NEW
HAMPSHIRE AND SOUTHWEST MAINE ON FRIDAY AS SOUTHWEST WINDS KEEP
THE SEA BREEZE OFFSHORE. TEMPERATURES ARE EXPECTED TO RISE INTO
THE UPPER 90S TO NEAR 100 DEGREES OVER ROCKINGHAM AND YORK
COUNTIES. RECORD HIGH TEMPERATURES IN CONCORD (98) AND PORTLAND
(94) ARE IN DANGER OF BEING BROKEN.
TIME FOR A BRIEF LESSON ON THE HEAT INDEX. THE HEAT INDEX WAS
DEVELOPED AS A WAY TO APPROXIMATE THE "FEELS LIKE" TEMPERATURE. IT
COMBINES THE EFFECTS OF HEAT AND HUMIDITY TO COME UP WITH THE HEAT
INDEX VALUE. THE CALCULATION MAKES SOME ASSUMPTIONS THAT ARE OFTEN
THE CASE IN THE MOST OPPRESSIVELY HOT AND HUMID AIR MASSES...
ESPECIALLY THOSE THAT OCCUR FREQUENTLY IN THE SOUTH. HOWEVER...
THESE ASSUMPTIONS ARE NOT ALWAYS PRESENT. SOME OF THE ASSUMPTIONS
INVOLVED INCLUDE A RELATIVE HUMIDITY OF AT LEAST 40 PERCENT AND
LIGHT WIND SPEEDS. IN A HUMID ENVIRONMENT... THE BODY`S NORMAL WAY
OF COOLING ITSELF THROUGH SWEAT IS HAMPERED AS THE SWEAT DOES NOT
EVAPORATE OFF THE SKIN QUICKLY ENOUGH. HOWEVER... WITH RELATIVE
HUMIDITY BELOW 40 PERCENT... THE HUMIDITY DOES NOT HAVE AS GREAT
OF AN EFFECT ON THE BODY. ALSO... IF WINDS ARE STRONGER THE SWEAT
IS ABLE TO EVAPORATE BETTER DUE TO BETTER AIR FLOW NEAR THE SKIN
SURFACE. FOR FRIDAY IN NORTHERN NEW ENGLAND... ONE OR BOTH OF
THESE ASSUMPTIONS WILL FAIL. FORECAST RELATIVE HUMIDITY FALLS
BELOW 40 PERCENT DURING THE PEAK HEAT OF THE AFTERNOON AND WINDS
WILL BE GUSTING TO 25 MPH. BOTH OF THESE FACTORS WILL ACT TO
LIMIT THE ACTUAL EFFECT OF THE HEAT AND HUMIDITY... THOUGH HEAT
INDEX VALUES WILL BE VERY HIGH. THIS DOES NOT RENDER THE HEAT
INDEX MEANINGLESS... BUT INDICATES THAT THESE FACTORS MAY
PROVIDE SOME SLIGHT RELIEF FROM WHAT CONDITIONS OTHERWISE COULD
BE.
IN SPITE OF ANY LIMITATIONS INVOLVED IN THE HEAT INDEX... THE HEAT
AND HUMIDITY IS GOING TO FEEL OPPRESSIVE ON FRIDAY ESPECIALLY BY
NORTHERN NEW ENGLAND STANDARDS. HEAT INDEX VALUES ARE FORECAST TO
RISE ABOVE 100 DEGREES FOR SOUTHEAST NEW HAMPSHIRE AND SOUTHWEST
MAINE. A HEAT ADVISORY HAS BEEN ISSUED TO DRAW ATTENTION TO THIS
THREAT AND ALERT PEOPLE TO THE THREATS CAUSED BY THE HIGH HEAT AND
HUMIDITY. IT IS POSSIBLE THAT HEAT INDEX VALUES MAY RISE TO 105
DEGREES OR HIGHER OVER ROCKINGHAM... STRAFFORD... AND YORK
COUNTIES. IF IT DOES SO... THIS WILL TECHNICALLY REACH EXCESSIVE
HEAT WARNING CRITERIA FOR NORTHERN NEW ENGLAND. IT WAS DECIDED NOT
TO ISSUE AN EXCESSIVE HEAT WARNING AT THIS TIME DUE TO THE
UNCERTAINTY REGARDING MAXIMUM TEMPERATURES ACTUALLY REACHING THE
EXTREME VALUES FORECAST AND THE POSSIBILITY OF LOWER DEW POINTS
AND GUSTY WINDS IN THE AFTERNOON. LATER FORECAST SHIFTS MAY FEEL
THE NEED TO UPGRADE TO A WARNING FOR PORTIONS OF THE ADVISORY AREA
IF THE CURRENT FORECAST HOLDS TRUE. THOSE WITH OUTDOOR ACTIVITIES
PLANNED... AND THOSE WITHOUT ACCESS TO AIR CONDITIONING WILL BE
PARTICULARLY VULNERABLE TO THE HEAT.
WITH THE HEAT AND HUMIDITY IN PLACE... THERE WILL ALSO BE PLENTY
OF INSTABILITY AVAILABLE FOR AFTERNOON THUNDERSTORMS. THIS APPEARS
MOST LIKELY IN NORTHERN AREAS. MODERATE TO STRONG MID/UPPER LEVEL
WINDS SUGGEST THAT ORGANIZED THUNDERSTORMS ARE POSSIBLE... AND
THUS SEVERE THUNDERSTORMS MAY OCCUR. HEAVY RAINFALL WILL ALSO BE A
THREAT DUE TO THE HUMID AIR IN PLACE.
TEMPERATURES WILL NOT COOL DOWN MUCH FRIDAY NIGHT AS HIGH HUMIDITY
AND SOME CLOUD COVER KEEP TEMPERATURES IN THE 70S AT NIGHT FOR
MOST AREAS. THIS WILL MAKE IT DIFFICULT FOR HOT BUILDINGS WITHOUT
AIR CONDITIONING TO COOL DOWN AT NIGHT.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
MAIN FOCUS OF THE EXTENDED FORECAST WILL BE SATURDAY AS SURFACE COLD
FRONT DROPS SOUTH INTO HOT AND VERY HUMID AIR MASS. DECENT HEIGHT
FALLS WILL BE ACCOMPANIED BY MODERATE TO STRONG MID-LEVEL
WINDS...ABOVE HIGHLY UNSTABLE SURFACE AIR. THIS WILL SET THE STAGE
FOR GOOD POTENTIAL FOR SEVERE WEATHER ON SATURDAY...ESPECIALLY IN
THE FORM OF DAMAGING WINDS. ONE LIMITING FACTOR COULD BE TIMING
OF PASSAGE OF PRE-FRONTAL TROUGH AND SUBSEQUENT COLD FRONT...WHICH
MAY CAUSE BEST CONVECTIVE FORCING TO OCCUR TOO EARLY.
HOWEVER...GIVEN WARM AND HUMID FRIDAY NIGHT...COULD SEE SEVERE
WEATHER AS EARLY AS LATE MORNING. THE SCATTERED THUNDERSTORMS WILL
LIKELY CONTINUE INTO EARLY EVENING...BUT SHOULD END QUICKLY
AFTER THAT...WITH COOLER AND AND LESS HUMID BEGINNING TO SPILL
INTO THE CWA BEFORE DAYBREAK SUNDAY.
THE COOLER AND LESS HUMID HIGH PRESSURE WILL REMAIN OVER THE CWA
INTO TUESDAY. THE NEXT CHANCE OF RAIN WILL BE LATE TUESDAY INTO
WEDNESDAY AS A WARM FRONT PUSHES NE INTO NEW ENGLAND.
&&
.AVIATION /22Z THURSDAY THROUGH TUESDAY/...
SHORT TERM /THROUGH FRIDAY NIGHT/...VFR EXPECTED THROUGH FRIDAY
NIGHT...EXCEPT FOR AFTERNOON/EVENING THUNDERSTORMS POSSIBLE AT
ALL TAF SITES AND LATE NIGHT FOG MAINLY AT LEB AND HIE WHICH COULD
LOWER CIG/VSBY.
LONG TERM...STRONG THUNDERSTORMS WITH HEAVY RAIN AND GUSTY WINDS
ARE LIKELY AT TIMES ON SAT INTO SAT EVENING. OTHERWISE EXPECT MAINLY
VFR THROUGH TUE.
&&
.MARINE...
SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...WILL UPDATE TO INPUT
LATEST OBSERVED DATA RESULTING IN NO MORE THAN A FEW TWEAKS TO THE
PREVIOUS FORECAST. SOUTHWEST WINDS WILL INCREASE ON FRIDAY AND MAY
SEE A FEW GUSTS APPROACH SCA LEVELS. WAVE HEIGHTS WILL INCREASE
AND MAY RISE TO AROUND THE 5 FT THRESHOLD FOR AN SCA FRIDAY
AFTERNOON INTO FRIDAY NIGHT OVER THE OPEN WATERS.
LONG TERM...BORDERLINE SCA ON SATURDAY WITH SEAS TO AROUND 5 FT...
AND SW WINDS APPROACHING 25 KTS. WINDS SHIFT TO NW SATURDAY NIGHT
AND WEAKEN. THE WATERS REMAIN GENERALLY QUIET SUNDAY THRU TUESDAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...HEAT ADVISORY FROM 10 AM TO 7 PM EDT FRIDAY FOR MEZ012-018>021-
023-024.
NH...HEAT ADVISORY FROM 10 AM TO 7 PM EDT FRIDAY FOR NHZ006-008>010-
013-014.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
420 PM EDT THU JUL 18 2013
.SYNOPSIS...
VERY HOT AND HUMID AIR MOVES IN FOR FRIDAY INTO SATURDAY. A COLD
FRONT WILL WILL CROSS THE REGION SATURDAY...SETTING OFF SHOWERS
AND THUNDERSTORMS...AND SOME OF THOSE STORMS COULD BE SEVERE.
COOLER AND LESS HUMID HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT
SUNDAY THOUGH TUESDAY.
&&
.NEAR TERM /TONIGHT/...
RELIED HEAVILY ON THE HRRR MODEL FOR THE FORECAST TONIGHT AS THIS
MODEL HAS HANDLED THINGS VERY WELL THE PAST FEW DAYS AND SEEMS TO
BE DOING SO ONCE AGAIN TODAY. CONVECTION HAS FIRED ON THE SEA
BREEZE BOUNDARY IN MAINE... WITH ACTIVITY TENDING TO FALL APART
AFTER IT ADVECTS INTO THE COOLER MARINE AIR. ADDITIONAL ISOLATED
STORMS HAVE DEVELOPED OVER THE HIGHER TERRAIN IN NEW HAMPSHIRE. A
LARGER AREA OF STORMS DEVELOPED OVER THE ADIRONDACKS OF UPSTATE
NEW YORK AND WILL CONTINUE TO PUSH EASTWARD THROUGH VERMONT AND
INTO NEW HAMPSHIRE THIS AFTERNOON. WIND SHEAR IS SUFFICIENT FOR
SUPERCELLS... AND ALREADY A FEW HAVE BEEN OBSERVED. DAMAGING WINDS
AND HAIL WOULD BE THE THREATS FROM STORMS TODAY... ALTHOUGH HEAVY
RAIN WILL ALSO OCCUR. MODERATE STORM MOTIONS SHOULD LIMIT THE
FLASH FLOODING THREAT. EXPECT MOST OF THE ACTIVITY THIS EVENING TO
DIE DOWN AND MOVE OFF TO THE EAST BY AROUND MIDNIGHT. TEMPERATURES
TONIGHT WILL BE WARM... WITH LOWS IN THE UPPER 60S AND LOW 70S.
FOG WILL BE POSSIBLE IN THE CONNECTICUT RIVER VALLEY.
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
HOT AND HUMID AIR OVER THE MID ATLANTIC STATES TODAY... EVIDENCED
BY A BROAD AREA OF +20 C TEMPERATURES AT 850 MB... WILL BE
ADVECTED NORTHEAST AND INTO NEW ENGLAND ON FRIDAY. GFS AND NAM IN
GOOD AGREEMENT ON 850 MB TEMPERATURES OF +21 C BY FRIDAY AFTERNOON
OVER THE SOUTHERN HALF OF THE FORECAST AREA. IN ADDITION...
SOUTHWEST FLOW WILL TRANSPORT HIGH DEW POINTS INTO THE AREA.
EXPECT THE DAY TO START OFF WITH LOW 70S DEW POINTS OVER MUCH OF
THE REGION. BUT A SURFACE TROUGH WILL PUSH EASTWARD ACROSS THE
AREA... SHIFTING WINDS FROM THE SOUTH TO THE WEST-SOUTHWEST. THIS
WEST TO SOUTHWEST WIND WILL HAVE A SIGNIFICANT DOWNSLOPING
COMPONENT TO IT... ALLOWING FOR GREATER MIXING. THIS MEANS THREE
THINGS... HIGHER TEMPERATURES... LOWER DEW POINTS... AND GREATER
WIND SPEEDS. AFTERNOON SOUNDINGS INDICATE THAT AS PEAK HEATING
OCCURS... DEW POINTS WILL FALL INTO THE MID 60S BEHIND THE SURFACE
TROUGH. WITH DOWNSLOPING CONDITIONS... THE HOTTEST TEMPERATURES
WILL OCCUR AT LOWER ELEVATIONS WHICH IN THIS CASE MEANS THE COAST.
IT DOES NOT LOOK LIKE THE SEA BREEZE WILL BE MUCH HELP OVER NEW
HAMPSHIRE AND SOUTHWEST MAINE ON FRIDAY AS SOUTHWEST WINDS KEEP
THE SEA BREEZE OFFSHORE. TEMPERATURES ARE EXPECTED TO RISE INTO
THE UPPER 90S TO NEAR 100 DEGREES OVER ROCKINGHAM AND YORK
COUNTIES. RECORD HIGH TEMPERATURES IN CONCORD (98) AND PORTLAND
(94) ARE IN DANGER OF BEING BROKEN.
TIME FOR A BRIEF LESSON ON THE HEAT INDEX. THE HEAT INDEX WAS
DEVELOPED AS A WAY TO APPROXIMATE THE "FEELS LIKE" TEMPERATURE. IT
COMBINES THE EFFECTS OF HEAT AND HUMIDITY TO COME UP WITH THE HEAT
INDEX VALUE. THE CALCULATION MAKES SOME ASSUMPTIONS THAT ARE OFTEN
THE CASE IN THE MOST OPPRESSIVELY HOT AND HUMID AIR MASSES...
ESPECIALLY THOSE THAT OCCUR FREQUENTLY IN THE SOUTH. HOWEVER...
THESE ASSUMPTIONS ARE NOT ALWAYS PRESENT. SOME OF THE ASSUMPTIONS
INVOLVED INCLUDE A RELATIVE HUMIDITY OF AT LEAST 40 PERCENT AND
LIGHT WIND SPEEDS. IN A HUMID ENVIRONMENT... THE BODY`S NORMAL WAY
OF COOLING ITSELF THROUGH SWEAT IS HAMPERED AS THE SWEAT DOES NOT
EVAPORATE OFF THE SKIN QUICKLY ENOUGH. HOWEVER... WITH RELATIVE
HUMIDITY BELOW 40 PERCENT... THE HUMIDITY DOES NOT HAVE AS GREAT
OF AN EFFECT ON THE BODY. ALSO... IF WINDS ARE STRONGER THE SWEAT
IS ABLE TO EVAPORATE BETTER DUE TO BETTER AIR FLOW NEAR THE SKIN
SURFACE. FOR FRIDAY IN NORTHERN NEW ENGLAND... ONE OR BOTH OF
THESE ASSUMPTIONS WILL FAIL. FORECAST RELATIVE HUMIDITY FALLS
BELOW 40 PERCENT DURING THE PEAK HEAT OF THE AFTERNOON AND WINDS
WILL BE GUSTING TO 25 MPH. BOTH OF THESE FACTORS WILL ACT TO
LIMIT THE ACTUAL EFFECT OF THE HEAT AND HUMIDITY... THOUGH HEAT
INDEX VALUES WILL BE VERY HIGH. THIS DOES NOT RENDER THE HEAT
INDEX MEANINGLESS... BUT INDICATES THAT THESE FACTORS MAY
PROVIDE SOME SLIGHT RELIEF FROM WHAT CONDITIONS OTHERWISE COULD
BE.
IN SPITE OF ANY LIMITATIONS INVOLVED IN THE HEAT INDEX... THE HEAT
AND HUMIDITY IS GOING TO FEEL OPPRESSIVE ON FRIDAY ESPECIALLY BY
NORTHERN NEW ENGLAND STANDARDS. HEAT INDEX VALUES ARE FORECAST TO
RISE ABOVE 100 DEGREES FOR SOUTHEAST NEW HAMPSHIRE AND SOUTHWEST
MAINE. A HEAT ADVISORY HAS BEEN ISSUED TO DRAW ATTENTION TO THIS
THREAT AND ALERT PEOPLE TO THE THREATS CAUSED BY THE HIGH HEAT AND
HUMIDITY. IT IS POSSIBLE THAT HEAT INDEX VALUES MAY RISE TO 105
DEGREES OR HIGHER OVER ROCKINGHAM... STRAFFORD... AND YORK
COUNTIES. IF IT DOES SO... THIS WILL TECHNICALLY REACH EXCESSIVE
HEAT WARNING CRITERIA FOR NORTHERN NEW ENGLAND. IT WAS DECIDED NOT
TO ISSUE AN EXCESSIVE HEAT WARNING AT THIS TIME DUE TO THE
UNCERTAINTY REGARDING MAXIMUM TEMPERATURES ACTUALLY REACHING THE
EXTREME VALUES FORECAST AND THE POSSIBILITY OF LOWER DEW POINTS
AND GUSTY WINDS IN THE AFTERNOON. LATER FORECAST SHIFTS MAY FEEL
THE NEED TO UPGRADE TO A WARNING FOR PORTIONS OF THE ADVISORY AREA
IF THE CURRENT FORECAST HOLDS TRUE. THOSE WITH OUTDOOR ACTIVITIES
PLANNED... AND THOSE WITHOUT ACCESS TO AIR CONDITIONING WILL BE
PARTICULARLY VULNERABLE TO THE HEAT.
WITH THE HEAT AND HUMIDITY IN PLACE... THERE WILL ALSO BE PLENTY
OF INSTABILITY AVAILABLE FOR AFTERNOON THUNDERSTORMS. THIS APPEARS
MOST LIKELY IN NORTHERN AREAS. MODERATE TO STRONG MID/UPPER LEVEL
WINDS SUGGEST THAT ORGANIZED THUNDERSTORMS ARE POSSIBLE... AND
THUS SEVERE THUNDERSTORMS MAY OCCUR. HEAVY RAINFALL WILL ALSO BE A
THREAT DUE TO THE HUMID AIR IN PLACE.
TEMPERATURES WILL NOT COOL DOWN MUCH FRIDAY NIGHT AS HIGH HUMIDITY
AND SOME CLOUD COVER KEEP TEMPERATURES IN THE 70S AT NIGHT FOR
MOST AREAS. THIS WILL MAKE IT DIFFICULT FOR HOT BUILDINGS WITHOUT
AIR CONDITIONING TO COOL DOWN AT NIGHT.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
MAIN FOCUS OF THE EXTENDED FORECAST WILL BE SATURDAY AS SURFACE COLD
FRONT DROPS SOUTH INTO HOT AND VERY HUMID AIR MASS. DECENT HEIGHT
FALLS WILL BE ACCOMPANIED BY MODERATE TO STRONG MID-LEVEL
WINDS...ABOVE HIGHLY UNSTABLE SURFACE AIR. THIS WILL SET THE STAGE
FOR GOOD POTENTIAL FOR SEVERE WEATHER ON SATURDAY...ESPECIALLY IN
THE FORM OF DAMAGING WINDS. ONE LIMITING FACTOR COULD BE TIMING
OF PASSAGE OF PRE-FRONTAL TROUGH AND SUBSEQUENT COLD FRONT...WHICH
MAY CAUSE BEST CONVECTIVE FORCING TO OCCUR TOO EARLY.
HOWEVER...GIVEN WARM AND HUMID FRIDAY NIGHT...COULD SEE SEVERE
WEATHER AS EARLY AS LATE MORNING. THE SCATTERED THUNDERSTORMS WILL
LIKELY CONTINUE INTO EARLY EVENING...BUT SHOULD END QUICKLY
AFTER THAT...WITH COOLER AND AND LESS HUMID BEGINNING TO SPILL
INTO THE CWA BEFORE DAYBREAK SUNDAY.
THE COOLER AND LESS HUMID HIGH PRESSURE WILL REMAIN OVER THE CWA
INTO TUESDAY. THE NEXT CHANCE OF RAIN WILL BE LATE TUESDAY INTO
WEDNESDAY AS A WARM FRONT PUSHES NE INTO NEW ENGLAND.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
SHORT TERM...VFR EXPECTED THROUGH FRIDAY APART FROM
AFTERNOON/EVENING THUNDERSTORMS AND LATE NIGHT FOG AT LEBANON AND
WHITEFIELD.
LONG TERM...STRONG THUNDERSTORMS WITH HEAVY RAIN AND GUSTY WINDS
ARE LIKELY AT TIMES ON SAT INTO SAT EVENING. OTHERWISE EXPECT MAINLY
VFR THROUGH TUE.
&&
.MARINE...
SHORT TERM...SOUTHWEST WINDS WILL INCREASE ON FRIDAY. WAVE HEIGHTS
MAY RISE TO AROUND 5 FT BY FRIDAY NIGHT.
LONG TERM...BORDERLINE SCA ON SATURDAY WITH SEAS TO AROUND 5 FT...
AND SW WINDS APPROACHING 25 KTS. WINDS SHIFT TO NW SATURDAY NIGHT
AND WEAKEN. THE WATERS REMAIN GENERALLY QUIET SUNDAY THRU TUESDAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...HEAT ADVISORY FROM 10 AM TO 7 PM EDT FRIDAY FOR MEZ012-018>021-
023-024.
NH...HEAT ADVISORY FROM 10 AM TO 7 PM EDT FRIDAY FOR NHZ006-008>010-
013-014.
MARINE...NONE.
&&
$$
SYNOPSIS...CEMPA
NEAR TERM...KIMBLE
SHORT TERM...KIMBLE
LONG TERM...CEMPA
AVIATION...CEMPA/KIMBLE
MARINE...CEMPA/KIMBLE
AREA FORECAST DISCUSSION
NWS GRAY ME
1242 PM EDT THU JUL 18 2013
.SYNOPSIS...
A WEAK FRONTAL BOUNDARY WILL STALL OVER SOUTHERN NEW ENGLAND TODAY
AND WILL LIFT NORTH AS A WARM FRONT THURSDAY NIGHT AND EARLY FRIDAY.
A SECOND COLD FRONT WILL APPROACH FROM THE NORTHWEST FRIDAY NIGHT
AND WILL CROSS THE REGION ON SATURDAY. HIGH PRESSURE WILL BUILD IN
BEHIND THE FRONT SATURDAY NIGHT THROUGH SUNDAY. HIGH PRESSURE WILL
SHIFT OFFSHORE ON MONDAY AND WILL REMAIN ANCHORED OFF THE NORTHEAST
COAST THROUGH WEDNESDAY.
&&
.NEAR TERM /TODAY/...
1245PM UPDATE...
SEA BREEZE HAS MOVED ONSHORE AND IS VISIBLE ON RADAR. ANOTHER NORTH
TO SOUTH ORIENTED BOUNDARY OVER FAR SOUTHWEST MAINE IS ALSO VISIBLE
AND ALREADY GENERATING WEAK CONVECTION. EXPECT SCATTERED SHOWERS AND
STORMS TO FORM ON THESE BOUNDARIES THIS AFTERNOON. MEANWHILE...
ADDITIONAL CONVECTION WILL DEVELOP OVER THE ADIRONDACKS IN UPSTATE
NEW YORK AND MOVE EASTWARD WITH THE UPPER LEVEL FLOW. THIS
CONVECTION MAY BE THE MOST LIKELY TO BECOME SEVERE AS SPEED SHEAR
WILL BE SUFFICIENT FOR SUPERCELLS OR MULTICELL CLUSTERS.
930AM UPDATE...
HAVE UPDATED THE FORECAST WITH SLIGHTLY ADJUSTED FORECAST THINKING
FOR TODAY. MORNING SOUNDING SHOWS A FAIR AMOUNT OF DRY AIR ALOFT
THAT WILL MIX DOWN WITH MODERATE HEATING THIS AFTERNOON. ALTHOUGH
TEMPERATURES WILL LIKELY REACH THE 90S IN SOME AREAS... DEW POINTS
WILL FALL INTO THE 60S EVEN IN SOUTHEAST NEW HAMPSHIRE. AS A
RESULT... THIS WILL KEEP HEAT INDEX VALUES BELOW ADVISORY LEVELS
THIS AFTERNOON ALTHOUGH IT WILL BE CLOSE. SHOULD STAY DRY THROUGH
THE MORNING AND INTO THE EARLY AFTERNOON. BUT A SEA BREEZE
BOUNDARY MAY BE THE FOCUS FOR THUNDERSTORM DEVELOPMENT AROUND 2 TO
4 PM. ALSO... TERRAIN MAY BE THE FOCUS FOR THUNDERSTORMS OVER
WESTERN NEW YORK AND SOUTHERN VERMONT WHICH WILL MOVE WEST AND
IMPACT NEW HAMPSHIRE AND WESTERN MAINE LATER IN THE EVENING. THERE
IS SOME CONCERN FOR HEAVY RAIN FROM THESE STORMS TODAY... BUT ALSO
CANNOT RULE OUT THE POSSIBILITY FOR SEVERE WEATHER. THERE IS NO
SEVERE WEATHER OUTLOOK FOR OUR AREA... AND SEVERE WEATHER IS NOT
EXPECTED TO BE WIDESPREAD AS THERE IS NO OBVIOUS SOURCE OF
SYNOPTIC SCALE LIFT. BUT SPEED SHEAR WILL BE STRONG ENOUGH TO
SUPPORT SUPERCELLS ESPECIALLY FURTHER NORTHEAST INTO MAINE FROM
PORTLAND NORTHWARD. THE CONCERN WITH ANY SUPERCELLS THAT FORM HERE
IS THAT THEY WOULD QUICKLY MOVE INTO THE MODIFIED MARINE
ENVIRONMENT BEHIND THE SEA BREEZE BOUNDARY... POSSIBLY LIMITING
THEIR IMPACT. HOWEVER... IF THEY CAN MAINTAIN THEMSELVES... THE
DIRECTIONAL AND SPEED SHEAR WOULD WARRANT CONCERN FOR ROTATING
STORMS. HRRR MODEL SEEMS TO HAVE A GOOD HANDLE ON CONVECTION THIS
AFTERNOON ONCE AGAIN... AND RELIED HEAVILY ON THIS MODEL FOR THE
FORECAST (ALTHOUGH OTHER MODELS ARE IN DECENT AGREEMENT).
PREVIOUS DISCUSSION...
PRE-FRONTAL TROUGH THAT CAUSED ALL THE CONVECTION OVER THE LAST
FEW HOURS IS MOVING EAST AT THE MOMENT. A COLD FRONT IS SAGGING
SOUTH FROM CANADA AND WILL MOVE INTO MAINE TODAY AND MAY MAKE IT
AS FAR SOUTH AS PORTLAND BY LATE IN THE DAY. WITH THE FRONT SLOWLY
MOVING SOUTH EXPECT A CHANCE OF AFTERNOON SHOWERS AND
THUNDERSTORMS TO BREAK OUT IN THE MOUNTAINS. LESSER CHANCES FARTHER
SOUTH. TEMPERATURES WILL WARM INTO THE LOWER 90S IN SOUTHERN AREAS.
&&
.SHORT TERM /TONIGHT AND FRIDAY/...
THE COLD FRONT WILL MOVE BACK NORTH LATE TONIGHT. EXPECT AN
INCREASED CHANCE OF SHOWERS AND THUNDER ALONG AND TO THE NORTH OF
THE FRONT TONIGHT IN CENTRAL AND NORTHEAST PORTIONS OF THE
FORECAST AREA. FOR FRIDAY THE HOT AIR SURGES IN WITH 850
TEMPERATURES AT OR JUST ABOVE 20C. EXPECT HIGH TEMPERATURES IN MID
AND UPPER 90S IN SW MAINE AND SOUTHERN NEW HAMPSHIRE. FRIDAYS
RECORD HIGH FOR CONCORD IS 98 AND THIS COULD BE ATTAINABLE. IN
PORTLAND THE RECORD HIGH IS 94 AND IF THE WINDS REMAIN SW THAT
RECORD COULD FALL TOO. LATER SHIFTS MAY NEED TO ISSUE A HEAT
ADVISORY FOR FRIDAY AS APPARENT TEMPERATURES MAY RISE TO ABOVE 100
DEGREES. EXPECT SCATTERED SHOWERS AND THUNDERSTORMS ESPECIALLY
IN NORTHERN AREAS FRIDAY AFTERNOON. WITH PWATS RUNNING CLOSE TO 2
INCHES EXPECT SOME HEAVY RAIN IN ANY THUNDERSTORMS FRIDAY AND HAVE
MENTIONED THIS IN THE GRIDS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
A VERY WARM AND MUGGY FRIDAY NIGHT ON TAP WITH TEMPERATURES ONLY
SETTLING INTO THE LOWER TO MID 70S AND DEW POINTS NOT MUCH DIFFERENT
IN SOUTHERN ZONES. WILL NOT SEE MUCH DIFFERENCE IN NORTHERN ZONES WHERE
LOWS WILL DIP INTO THE MID 60S TO NEAR 70. WILL SEE A CHANCE OF
SHOWERS OR THUNDERSTORMS THROUGH THE NIGHT WITH HIGHEST POPS IN THE
NORTH AS A COLD FRONT APPROACHES FROM THE NORTHWEST.
SATURDAY STILL LOOKING TO BE A BUSY SEVERE WEATHER DAY AS A STRONG
COLD FRONT SLICES IN FROM THE NORTHWEST DURING THE AFTERNOON AND
EVENING. VERY STRONG FLOW ALOFT WILL LIKELY PRODUCE NUMEROUS REPORTS
OF WIND DAMAGE FROM BOWING LINE SEGMENTS IN THE HIGHLY SHEARED
ENVIRONMENT. WILL BE ANOTHER DAY OF HOT AND MUGGY CONDITIONS WITH
MOST AREAS REACHING THE MID 80S TO LOWER 90S.
COLD FRONT WILL FINALLY PUSH OFFSHORE SATURDAY EVENING TAKING ANY
LINGERING SHOWERS AND THUNDERSTORMS WITH IT. REFRESHING NORTH WINDS
WILL BRING MUCH COOLER AND DRYER AIR BACK TO THE REGION OVERNIGHT AS
HIGH PRESSURE BUILDS IN FROM THE WEST. WILL SEE LOWS BY SUNDAY
MORNING IN THE LOWER 50S NORTH AND UPPER 50S TO LOWER 60S SOUTH.
HIGH PRESSURE WILL CONTINUE TO BUILD IN FROM THE WEST SUNDAY AND
MONDAY SETTING THE STAGE FOR SOME VERY AGREEABLE SUMMER WEATHER.
EXPECT HIGHS BOTH DAYS IN THE 70S TO NEAR 80.
HIGH PRESSURE WILL SHIFT OFFSHORE BY LATE IN THE DAY MONDAY AND WILL
REMAIN NEARLY STATIONARY OFF THE EAST COAST TUESDAY AND WEDNESDAY.
WILL SEE A GRADUAL MODERATION IN TEMPERATURE AND HUMIDITY AS RETURN
FLOW BRINGS WARMER AIR BACK INTO THE REGION. LOW PRESSURE TRACKING
NORTH THROUGH THE EASTERN GREAT LAKES WILL DRIVE A COLD FRONT TOWARD
THE REGION WEDNESDAY NIGHT AND THURSDAY BRINGING WITH IT A CHANCE OF
SHOWERS FOR LATER IN THE WEEK.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
SHORT TERM...SOME MVFR/IFR POSSIBLE EARLY THIS MORNING IN SOME FOG
OTHERWISE VFR EXCEPT IN ANY SHOWERS AND THUNDERSTORMS.
LONG TERM...VFR FRIDAY NIGHT WITH AREAS IFR/LIFR CEILINGS/VSBY IN
MORNING VALLEY FOG. VFR SATURDAY WITH AREAS OF MVFR/IFR CEILINGS
AND VSBY IN WIDESPREAD SHOWERS AND THUNDERSTORMS. VFR SATURDAY
NIGHT THROUGH MONDAY.
&&
.MARINE...
SHORT TERM...WIND AND SEAS WILL REMAIN BELOW SCA CRITERIA.
LONG TERM...SCA LIKELY FOR FRIDAY NIGHT INTO SATURDAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
NEAR TERM UPDATE... KIMBLE
AREA FORECAST DISCUSSION
NWS GRAY ME
940 AM EDT THU JUL 18 2013
.SYNOPSIS...
A WEAK FRONTAL BOUNDARY WILL STALL OVER SOUTHERN NEW ENGLAND TODAY
AND WILL LIFT NORTH AS A WARM FRONT THURSDAY NIGHT AND EARLY FRIDAY.
A SECOND COLD FRONT WILL APPROACH FROM THE NORTHWEST FRIDAY NIGHT
AND WILL CROSS THE REGION ON SATURDAY. HIGH PRESSURE WILL BUILD IN
BEHIND THE FRONT SATURDAY NIGHT THROUGH SUNDAY. HIGH PRESSURE WILL
SHIFT OFFSHORE ON MONDAY AND WILL REMAIN ANCHORED OFF THE NORTHEAST
COAST THROUGH WEDNESDAY.
&&
.NEAR TERM /TODAY/...
930AM UPDATE...
HAVE UPDATED THE FORECAST WITH SLIGHTLY ADJUSTED FORECAST THINKING
FOR TODAY. MORNING SOUNDING SHOWS A FAIR AMOUNT OF DRY AIR ALOFT
THAT WILL MIX DOWN WITH MODERATE HEATING THIS AFTERNOON. ALTHOUGH
TEMPERATURES WILL LIKELY REACH THE 90S IN SOME AREAS... DEW POINTS
WILL FALL INTO THE 60S EVEN IN SOUTHEAST NEW HAMPSHIRE. AS A
RESULT... THIS WILL KEEP HEAT INDEX VALUES BELOW ADVISORY LEVELS
THIS AFTERNOON ALTHOUGH IT WILL BE CLOSE. SHOULD STAY DRY THROUGH
THE MORNING AND INTO THE EARLY AFTERNOON. BUT A SEA BREEZE
BOUNDARY MAY BE THE FOCUS FOR THUNDERSTORM DEVELOPMENT AROUND 2 TO
4 PM. ALSO... TERRAIN MAY BE THE FOCUS FOR THUNDERSTORMS OVER
WESTERN NEW YORK AND SOUTHERN VERMONT WHICH WILL MOVE WEST AND
IMPACT NEW HAMPSHIRE AND WESTERN MAINE LATER IN THE EVENING. THERE
IS SOME CONCERN FOR HEAVY RAIN FROM THESE STORMS TODAY... BUT ALSO
CANNOT RULE OUT THE POSSIBILITY FOR SEVERE WEATHER. THERE IS NO
SEVERE WEATHER OUTLOOK FOR OUR AREA... AND SEVERE WEATHER IS NOT
EXPECTED TO BE WIDESPREAD AS THERE IS NO OBVIOUS SOURCE OF
SYNOPTIC SCALE LIFT. BUT SPEED SHEAR WILL BE STRONG ENOUGH TO
SUPPORT SUPERCELLS ESPECIALLY FURTHER NORTHEAST INTO MAINE FROM
PORTLAND NORTHWARD. THE CONCERN WITH ANY SUPERCELLS THAT FORM HERE
IS THAT THEY WOULD QUICKLY MOVE INTO THE MODIFIED MARINE
ENVIRONMENT BEHIND THE SEA BREEZE BOUNDARY... POSSIBLY LIMITING
THEIR IMPACT. HOWEVER... IF THEY CAN MAINTAIN THEMSELVES... THE
DIRECTIONAL AND SPEED SHEAR WOULD WARRANT CONCERN FOR ROTATING
STORMS. HRRR MODEL SEEMS TO HAVE A GOOD HANDLE ON CONVECTION THIS
AFTERNOON ONCE AGAIN... AND RELIED HEAVILY ON THIS MODEL FOR THE
FORECAST (ALTHOUGH OTHER MODELS ARE IN DECENT AGREEMENT).
PREVIOUS DISCUSSION...
PRE-FRONTAL TROUGH THAT CAUSED ALL THE CONVECTION OVER THE LAST
FEW HOURS IS MOVING EAST AT THE MOMENT. A COLD FRONT IS SAGGING
SOUTH FROM CANADA AND WILL MOVE INTO MAINE TODAY AND MAY MAKE IT
AS FAR SOUTH AS PORTLAND BY LATE IN THE DAY. WITH THE FRONT SLOWLY
MOVING SOUTH EXPECT A CHANCE OF AFTERNOON SHOWERS AND
THUNDERSTORMS TO BREAK OUT IN THE MOUNTAINS. LESSER CHANCES FARTHER
SOUTH. TEMPERATURES WILL WARM INTO THE LOWER 90S IN SOUTHERN AREAS.
&&
.SHORT TERM /TONIGHT AND FRIDAY/...
THE COLD FRONT WILL MOVE BACK NORTH LATE TONIGHT. EXPECT AN
INCREASED CHANCE OF SHOWERS AND THUNDER ALONG AND TO THE NORTH OF
THE FRONT TONIGHT IN CENTRAL AND NORTHEAST PORTIONS OF THE
FORECAST AREA. FOR FRIDAY THE HOT AIR SURGES IN WITH 850
TEMPERATURES AT OR JUST ABOVE 20C. EXPECT HIGH TEMPERATURES IN MID
AND UPPER 90S IN SW MAINE AND SOUTHERN NEW HAMPSHIRE. FRIDAYS
RECORD HIGH FOR CONCORD IS 98 AND THIS COULD BE ATTAINABLE. IN
PORTLAND THE RECORD HIGH IS 94 AND IF THE WINDS REMAIN SW THAT
RECORD COULD FALL TOO. LATER SHIFTS MAY NEED TO ISSUE A HEAT
ADVISORY FOR FRIDAY AS APPARENT TEMPERATURES MAY RISE TO ABOVE 100
DEGREES. EXPECT SCATTERED SHOWERS AND THUNDERSTORMS ESPECIALLY
IN NORTHERN AREAS FRIDAY AFTERNOON. WITH PWATS RUNNING CLOSE TO 2
INCHES EXPECT SOME HEAVY RAIN IN ANY THUNDERSTORMS FRIDAY AND HAVE
MENTIONED THIS IN THE GRIDS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
A VERY WARM AND MUGGY FRIDAY NIGHT ON TAP WITH TEMPERATURES ONLY
SETTLING INTO THE LOWER TO MID 70S AND DEW POINTS NOT MUCH DIFFERENT
IN SOUTHERN ZONES. WILL NOT SEE MUCH DIFFERENCE IN NORTHERN ZONES WHERE
LOWS WILL DIP INTO THE MID 60S TO NEAR 70. WILL SEE A CHANCE OF
SHOWERS OR THUNDERSTORMS THROUGH THE NIGHT WITH HIGHEST POPS IN THE
NORTH AS A COLD FRONT APPROACHES FROM THE NORTHWEST.
SATURDAY STILL LOOKING TO BE A BUSY SEVERE WEATHER DAY AS A STRONG
COLD FRONT SLICES IN FROM THE NORTHWEST DURING THE AFTERNOON AND
EVENING. VERY STRONG FLOW ALOFT WILL LIKELY PRODUCE NUMEROUS REPORTS
OF WIND DAMAGE FROM BOWING LINE SEGMENTS IN THE HIGHLY SHEARED
ENVIRONMENT. WILL BE ANOTHER DAY OF HOT AND MUGGY CONDITIONS WITH
MOST AREAS REACHING THE MID 80S TO LOWER 90S.
COLD FRONT WILL FINALLY PUSH OFFSHORE SATURDAY EVENING TAKING ANY
LINGERING SHOWERS AND THUNDERSTORMS WITH IT. REFRESHING NORTH WINDS
WILL BRING MUCH COOLER AND DRYER AIR BACK TO THE REGION OVERNIGHT AS
HIGH PRESSURE BUILDS IN FROM THE WEST. WILL SEE LOWS BY SUNDAY
MORNING IN THE LOWER 50S NORTH AND UPPER 50S TO LOWER 60S SOUTH.
HIGH PRESSURE WILL CONTINUE TO BUILD IN FROM THE WEST SUNDAY AND
MONDAY SETTING THE STAGE FOR SOME VERY AGREEABLE SUMMER WEATHER.
EXPECT HIGHS BOTH DAYS IN THE 70S TO NEAR 80.
HIGH PRESSURE WILL SHIFT OFFSHORE BY LATE IN THE DAY MONDAY AND WILL
REMAIN NEARLY STATIONARY OFF THE EAST COAST TUESDAY AND WEDNESDAY.
WILL SEE A GRADUAL MODERATION IN TEMPERATURE AND HUMIDITY AS RETURN
FLOW BRINGS WARMER AIR BACK INTO THE REGION. LOW PRESSURE TRACKING
NORTH THROUGH THE EASTERN GREAT LAKES WILL DRIVE A COLD FRONT TOWARD
THE REGION WEDNESDAY NIGHT AND THURSDAY BRINGING WITH IT A CHANCE OF
SHOWERS FOR LATER IN THE WEEK.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
SHORT TERM...SOME MVFR/IFR POSSIBLE EARLY THIS MORNING IN SOME FOG
OTHERWISE VFR EXCEPT IN ANY SHOWERS AND THUNDERSTORMS.
LONG TERM...VFR FRIDAY NIGHT WITH AREAS IFR/LIFR CEILINGS/VSBY IN
MORNING VALLEY FOG. VFR SATURDAY WITH AREAS OF MVFR/IFR CEILINGS
AND VSBY IN WIDESPREAD SHOWERS AND THUNDERSTORMS. VFR SATURDAY
NIGHT THROUGH MONDAY.
&&
.MARINE...
SHORT TERM...WIND AND SEAS WILL REMAIN BELOW SCA CRITERIA.
LONG TERM...SCA LIKELY FOR FRIDAY NIGHT INTO SATURDAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
NEAR TERM UPDATE... KIMBLE
AREA FORECAST DISCUSSION
NWS GAYLORD MI
358 PM EDT THU JUL 18 2013
.SYNOPSIS...
ISSUED AT 358 PM EDT THU JUL 18 2013
ONE MORE DAY OF HOT AND HUMID CONDITIONS ARE EXPECTED ACROSS
NORTHERN MICHIGAN FRIDAY BEFORE A COUPLE OF COLD FRONTS PASSING
THROUGH THE GREAT LAKES WILL COOL THINGS DOWN DRAMATICALLY BY
SATURDAY. PASSAGE OF THESE FRONTS WILL BE ACCOMPANIED BY
THUNDERSTORM ACTIVITY...SOME OF WHICH COULD BE SEVERE OVERNIGHT
AND INTO FRIDAY. THE SEVERE WEATHER THREAT WILL END BY FRIDAY
EVENING...WITH A DRY AND PLEASANT WEEKEND ON TAP.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 358 PM EDT THU JUL 18 2013
HIGH IMPACT WEATHER POTENTIAL: ISOLATED SEVERE THUNDERSTORMS
POSSIBLE THROUGH EARLY EVENING. INCREASING THREAT FOR DAMAGING
WINDS TONIGHT OVER EASTERN UPPER AND THE TIP OF THE MITT...MOVING
SOUTH INTO NORTHERN LOWER MICHIGAN ON FRIDAY.
HOT AND HUMID WEATHER CONTINUES...WITH HEAT ADVISORIES BEING
CONFINED CLOSER TO SAGINAW BAY FOR THE DAY ON FRIDAY AHEAD OF
ARRIVING COLD FRONT.
OVERVIEW: FLAT RIDGING CONTINUES ACROSS THE GREAT LAKES REGION THIS
AFTERNOON WITH STRONGER SHORTWAVE ENERGY NOW BECOMING EVIDENT
DROPPING OUT OF NORTHERN MANITOBA...WITH AN ADDITIONAL WAVE OVER
SOUTHERN SASKATCHEWAN. AT THE SURFACE...LOW PRESSURE HAS TAKEN
SHAPE OVER EASTERN NORTH DAKOTA THIS HOUR WITH QUASI-STATIONARY
WARM FRONT EXTENDING EAST ACROSS NORTHERN MINNESOTA AND UPPER
MICHIGAN. STORMS HAVE PERCOLATED ALONG THIS BOUNDARY ALL DAY GIVEN
SOUPY WARM SECTOR AIRMASS AND SOUTHWESTERLY WINDS RIDING OVER THE
BOUNDARY IN THE PRESENCE OF AMPLE UNCAPPED INSTABILITY AND GRADUALLY
INCREASING DEEP LAYER SHEAR. ON THE MESOSCALE...AND OUTFLOW
BOUNDARY WORKED SOUTH INTO NORTHERN LOWER HELPING TO TRIGGER
CONVECTION SOUTH OF THE FRONT...WITH SOME OF THIS ACTIVITY ONGOING
AS I TYPE. TEMPS IN AREAS NOT SEEING RAINFALL ARE NOT DISAPPOINTING
THE HOT/HUMID TALK OF LATE...WITH TVC 96 AND CAD 97 THIS HOUR.
THROUGH EARLY EVENING: ISOLATED TO SCATTERED TSRA ACTIVITY WILL
CONTINUE OVER NORTHERN LOWER...ALTHOUGH DECREASING IN COVERAGE AS WE
AWAIT FURTHER DEVELOPMENT UPSTREAM.
TONIGHT: BROAD AREA OF HEIGHT FALLS OVERSPREADS THE GREAT LAKES
REGION AHEAD OF STRONG SHORTWAVE WHOSE CORE WILL BE DROPPING THROUGH
NORTHERN MANITOBA. BENEATH THIS FEATURE THE SURFACE LOW WILL TRACK
NORTH AND EAST...TO NEAR THE SOUTHERN SHORE OF JAMES BAY BY DAYBREAK
FRIDAY. HEIGHT FALLS AND TIME OF DAY WILL COAX A STRENGTHENING LLJ
AT H8 FROM NORTHERN WISCONSIN NORTH AND EAST ACROSS LAKE SUPERIOR.
SYNOPTIC SETUP AND SHEAR PARAMETERS CERTAINLY FAVOR PROGRESSIVE MCS
DEVELOPMENT WITH OVER 30KTS OF 0-3KM BULK SHEAR...BUT NO MORE THAN
10KTS ABOVE THIS TO 6KM. THE QUESTION BECOMES...WHERE IS THIS
CONVECTION LIKELY TO FORM/MOVE?
THE SYNOPTICALLY-FAVORED LOCATION WOULD BE NEAR OR JUST NORTH OF LAKE
SUPERIOR GIVEN THE CURRENT FRONTAL BOUNDARY AND EXPECTED LLJ
LOCATION. THIS IS WELL SHOWN BY THE NEW 12Z NAM AND PROBABLY THE
STRONGEST GUIDANCE CONSENSUS WHICH BRINGS TO DISTINCT CONVECTIVE
COMPLEXES OVER OR NORTH OF MY NORTHERN ZONES. AFTERNOON RADAR
TRENDS...HOWEVER...SUGGEST DEVELOPMENT A LITTLE FURTHER SOUTH AND
WEST...OVER THE ARROWHEAD OF MINNESOTA ALONG OUTFLOW BOUNDARY IN
THIS AREA. EARLY AFTERNOON HRRR IS ONTO THIS TREND...AND WITH
FORWARD-PROPAGATING CORFIDI VECTORS SUGGESTING AN ESE STORM
MOTION...LOOKS TO BRING ACTIVITY TOWARDS EASTERN UPPER LATER THIS
EVENING...WITH PERHAPS MORE ACTIVITY DEVELOPING UPSTREAM THROUGH THE
FIRST HALF OF TONIGHT AS THE LLJ STRENGTHENS IMMEDIATELY AHEAD OF
THE SURFACE COLD FRONT. THUS...WILL INCREASE POPS OVER EASTERN
UPPER TO LIKELY DURING THE EVENING HOURS...BUT KEEP LIKELIES
PRIMARILY RESTRICTED TO EASTERN UPPER OVERNIGHT GIVEN EXPECTED STORM
PROPAGATION. SOME ROGUE STORM DEVELOPMENT TO THE SOUTH IS
POSSIBLE...BUT LOWER POPS WARRANTED HERE. SEVERE THREAT IS
THERE...MORE ISOLATED WIND/HAIL IN THE NEAR TERM...WITH A MORE
ORGANIZED WIND THREAT TAKING SHAPE THIS EVENING.
REALLY LIKE INHERITED VERY WARM OVERNIGHT LOWS GIVEN INCREASING
CLOUD COVER AND COUPLED BOUNDARY LAYER FLOW NOT GIVING TEMPERATURES
MUCH ROOM TO FALL. SO...LOOKING LIKE THE LAST UNCOMFORTABLE SLEEPING
NIGHT MAY BE THE WORST /AT LEAST OVER NORTHERN LOWER/ WHERE MID TO
UPPER 70S SHOULD ABOUT DO IT.
FRIDAY: SOMEWHAT UNUSUAL FOR THE APX CWA SO FAR THIS WARM
SEASON...WE HAVE A COLD FRONT PROGGED TO PUSH THROUGH THE FORECAST
AREA IN THE MIDDLE OF PEAK HEATING. CLEARLY...OVERNIGHT CONVECTIVE
ACTIVITY WILL HAVE A HUGE IMPACT ON WHAT HAPPENS THUNDERSTORM-WISE
DURING THE DAY. COULD VERY WELL BE SOME ONGOING ACTIVITY ACROSS THE
CWA EARLY...WITH THE BEST CHANCES AGAIN BEING OVER EASTERN
UPPER...CLOSEST TO THE ARRIVING COLD FRONT. THIS AT LEAST SPELLS
THE POTENTIAL FOR SOME DESTABILIZATION AHEAD OF AFOREMENTIONED COLD
FRONT /ESP OVER NORTHERN LOWER/ WHICH LOOKS TO PUSH THROUGH THE CWA
IN THE 18-00Z TIME FRAME. SHEAR PARAMETERS ARE IMPRESSIVE AS THE
PRIMARY BELT OF THE WESTERLIES SINKS INTO OUR AREA. 0-3KM BULK
SHEAR REACHES 40KTS...WITH 50KTS+ OF 0-6KM SHEAR. SHEAR LOOKS TO
ONLY HAVE A SLIGHT ANGLE TO THE ARRIVING BOUNDARY...SO A LINEAR MODE
WITH EMBEDDED BOWING SEGMENTS COULD CERTAINLY BE SUPPORTED. THIS IS
WELL CAPTURED BY THE DAY 2 SLIGHT RISK AREA FROM SPC.
AS FOR TEMPERATURES AND HEAT ADVISORY CONCERNS...THE EARLIER
EXPANSION OF THE HEAT ADVISORY TO THE SOUTHEASTERN ZONES FOR THE DAY
LOOKS RIGHT ON...GIVEN STRENGTHENING SOUTHWEST WINDS GIVING SOME
DOWNSLOPING ASSISTANCE TO THESE AREAS...WHICH SHOULD PUSH TEMPS INTO
THE LOW/MID 90S BEFORE CONVECTIVE ACTIVITY ARRIVES FROM THE NORTH
AND WEST. ELSEWHERE...LOW TO MID 80S LOOK GOOD GIVEN EXPECTED CLOUD
COVER AND RAINFALL.
&&
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 358 PM EDT THU JUL 18 2013
RECENT TRENDS...TEMPERATURES: HOT...OBVIOUSLY. 1-3C ABOVE NORMAL
LAST 7 DAYS AND PRETTY MUCH FOR THE MONTH OF JULY THUS FAR.
PRECIPITATION/HYDROLOGY: BAND OF HEAVIER PRECIPITATION ACROSS
EASTERN UPPER/STRAITS REGION LAST NIGHT (RADAR ESTIMATES 3+ INCHES
FAR WESTERN MACKINAC/SCHOOLCRAFT COUNTIES) MOST SUBSTANTIAL RAINFALL
OF LAST SEVEN DAYS...OUTSIDE OF SCATTERED DIURNAL ACTIVITY MUCH OF
NORTHERN LOWER MICHIGAN HASN`T SEEN A DROP. 30 DAY STANDARDIZED
PRECIP INDEX CONTINUING TO TREND DRIER...ESPECIALLY ACROSS PORTIONS
OF UPPER MICHIGAN THAT SAW GOOD RAINS OVERNIGHT. STREAMFLOWS ON
AREA RIVERS STILL MOSTLY NEAR NORMAL...HYDROGRAPHS FLAT GIVEN LACK
OF RENEWED RUNOFF. TOPSOIL MOISTURE STILL IN GOOD SHAPE DESPITE
RECENT DRYNESS.
LARGE SCALE PATTERN/FORECAST...CONTINENTAL U.S. DOMINATED BY FLAT
RIDGING...WITH THE SOUTHERN EDGE OF THE MAIN WESTERLIES RUNNING
STRAIGHT WEST-EAST ALONG THE CANADIAN BORDER. PATTERN MORE BLOCKY
UPSTREAM ACROSS THE PACIFIC WITH "OFF THE CHART" -EPO/-WPO INDICES.
BALL OF ENERGY EMERGING FROM ABOVE THE ARCTIC CIRCLE AND ENTERING
FAR NORTHERN SASKATCHEWAN/MANITOBA THIS AFTERNOON WILL BE THE
CATALYST TO THE END OF THE CURRENT HEAT AND HUMIDITY THAT HAS BEEN
LINGERING OVER THE UPPER LAKES THIS WEEK. STRONG HEIGHT FALLS WILL
DROP ACROSS THE REGION FRIDAY AND DRIVE COOLER AIR INTO MICHIGAN FOR
THE WEEKEND. QUASI-ZONAL FLOW THEN FORECAST TO SET UP ACROSS THE
NORTHERN HALF OF THE CONUS FOR THE FIRST PART OF NEXT WEEK...WITH
SOME LOW AMPLITUDE TROUGHING FROM THE GREAT LAKES/OHIO VALLEY
NORTHEAST INTO NEW ENGLAND.
AHEAD OF THE CANADIAN HEIGHT FALLS WILL BE A PAIR OF COLD FRONTS
THAT WILL SWEEP ACROSS NORTHERN MICHIGAN FRIDAY/FRIDAY NIGHT. THIS
WILL PUSH A REFRESHINGLY COOLER/DRIER AIR MASS INTO THE UPPER LAKES
SATURDAY...WHILE HIGH PRESSURE SETTLES INTO THE REGION FOR SUNDAY.
HIGH PRESSURE RETREATS TO THE EAST MONDAY WITH RETURN FLOW OF WARMER
AIR BACK INTO THE UPPER MIDWEST/UPPER LAKES GETTING UNDERWAY. MAIN
FORECAST CONCERN THROUGH THE WEEKEND WILL BE WITH THE TRANSITION
FROM WARM/MUGGY TO COOLER WEATHER FRIDAY NIGHT.
FRIDAY NIGHT THROUGH SUNDAY: WEATHER...LEAD COLD FRONT WILL LIKELY
STILL BE IN THE VICINITY OF THE M-72/US-10 CORRIDOR FRIDAY
EVENING...WITH CONVECTION (POTENTIALLY SEVERE) LIKELY ONGOING AHEAD
OF THIS BOUNDARY WHICH SHOULD SINK INTO SOUTHERN LOWER MICHIGAN BY
MIDNIGHT. SECONDARY BOUNDARY COMES IN HOT ON ITS HEELS...PUSHED
ALONG BY THE MAIN SHORT WAVE TROUGH THAT WILL BE DIGGING SOUTHEAST.
MUCH OF THE FORCING ALOFT LOOKS TO REMAIN NORTH OF THE FORECAST
AREA...SOME QG SUBSIDENCE CROSSES NORTHERN MICHIGAN BEHIND THE LEAD
FRONT. SO WILL RUN WITH THUNDERSTORM CHANCES BASICALLY SOUTH OF A
MBL-APN LINE FRIDAY EVENING...AND DRY THINGS OUT THEREAFTER HEADING
INTO SATURDAY. WEAK SHORT WAVE TROUGH WILL TRACK THROUGH THE
MIDWEST SUNDAY...WHICH COULD PUSH CLOUDS INTO NORTHWEST LOWER DURING
THE AFTERNOON HOURS.
WINDS...SHIFTING TO THE NORTHWEST BEHIND SECONDARY COLD FRONT EARLY
SATURDAY MORNING...WINDS WILL BE A BIT GUSTY SATURDAY GIVEN GOOD
POST-FRONTAL MIXING (LOW LEVEL COLD ADVECTION/DIURNAL HEATING) ON
THE ORDER OF 20+MPH. WINDS FORECAST TO SETTLE DOWN SATURDAY NIGHT
AS HIGH BUILDS IN AND GRADIENT DROPS OFF. SUNDAY WINDS WILL BE
LIGHT AND DOMINATED BY LAKE BREEZE EVOLUTION.
TEMPERATURES...OVERNIGHT LOWS SHOULD FINALLY BREAK INTO THE 50S
ACROSS EASTERN UPPER AND MUCH OF NORTHWEST/NORTH CENTRAL LOWER
SATURDAY MORNING. SHOULD SEE A NICE DROP IN HUMIDITY EXPECTED
SATURDAY WITH DEW POINTS FALLING INTO THE 40S DURING THE AFTERNOON.
SATURDAY AFTERNOON HIGHS 65-70 EASTERN UPPER...UPPER 60S-LOWER 70S
MUCH OF NORTHWEST LOWER WITH MID-UPPER 70S NORTHEAST LOWER.
SEASONABLY COOL LOWS FOR SUNDAY MORNING WITH TEMPERATURES DROPPING
INTO THE 40S AWAY FROM THE IMMEDIATE LAKESHORES. SUNDAY HIGHS
AROUND 70-MID 70S EXPECTED.
EXTENDED FORECAST (MONDAY THROUGH THURSDAY): MIDWEST SHORT WAVE
CURRENTLY LOOKS AS IF IT WILL PASS SOUTH OF LOWER MICHIGAN AND INTO
THE OHIO VALLEY SUNDAY NIGHT/MONDAY. IF THAT IS THE CASE THEN WILL
PROBABLY START THE NEW WORK WEEK WITH A DRY FORECAST. BETTER THREAT
FOR RAIN MAY ARRIVE WITH A COLD FRONT HEADING INTO THE MIDWEEK
PERIOD...THEN WILL START THE NEW THURSDAY FORECAST OUT DRY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 143 PM EDT THU JUL 18 2013
SUMMARY: SCATTERED SHOWER AND THUNDERSTORM ACTIVITY WILL CONTINUE
INTO TONIGHT AS A STATIONARY FRONT BISECTS THE REGION. A POTENT
COLD FRONT WILL ARRIVE ON FRIDAY BRINGING A ROUND OF WIDESPREAD
SHOWERS AND THUNDERSTORMS. IMPROVING CONDITIONS WILL ARRIVE AT THE
VERY END...OR JUST AFTER THE END OF THE UPCOMING TAF PERIOD.
SHOWER AND THUNDERSTORM ACTIVITY LOOK MOST LIKELY TO IMPACT PLN
HEADING INTO THE EVENING HOURS...WITH ACTIVITY CURRENTLY OVER NE
LOWER EXPECTED TO REMAIN SOUTHEAST OF MBL-TVC-APN. A SEVERE STORM
CANNOT BE RULED OUT. OVERNIGHT...EXPECT NUMEROUS SHOWERS AND
THUNDERSTORMS ACROSS EASTERN UPPER...THAT MAY SINK SOUTH TOWARDS
PLN. OTHERWISE...FAR BETTER CHANCES FOR MORE WIDESPREAD
SHOWERS/STORMS COME FRIDAY MORNING WITH THE COLD FRONT. WILL
MENTION A FEW HOUR PERIOD OF TSRA AT THE MOST LIKELY TIME FOR
THESE TO MOVE THROUGH...WITH IMPROVEMENT TOWARDS THE VERY END OF
THE TAF PERIOD AT PLN.
LLWS: SOUTHWESTERLY LOW LEVEL JET WILL STRENGTHEN THIS EVENING
WITH 35KT WINDS EXPECTED AT 2KFT.
WINDS GENERALLY BECOMING WEST SOUTHWEST AROUND 10KTS THIS EVENING
AND OVERNIGHT BEFORE STRENGTHENING TO 14G20KTS FROM THE SOUTHWEST
AHEAD OF THE FRONT ON FRIDAY. EXPECT A WIND SHIFT TO WEST
NORTHWEST BY FRIDAY AFTERNOON.
&&
.MARINE...
ISSUED AT 358 PM EDT THU JUL 18 2013
SUMMARY: A LOW PRESSURE SYSTEM WILL PASS NORTH OF THE GREAT LAKES
TONIGHT AND ON FRIDAY...WITH STRENGTHENING SOUTHWESTERLY WINDS
EXPECTED AHEAD OF AN APPROACHING COLD FRONT. NORTHWEST WINDS WILL
DEVELOP IN THE WAKE OF THIS SYSTEM ON SATURDAY WITH VERY QUIET
CONDITIONS TO END THE WEEKEND AS HIGH PRESSURE SETTLES OVERHEAD.
WILL ISSUE SMALL CRAFTS FOR LATE TONIGHT AND FRIDAY ACROSS MOST OF
NORTHERN LAKE MICHIGAN GIVEN THE STRENGTHENING SOUTHWESTERLY FLOW
THIS EVENING. THESE WILL LIKELY NEED TO BE EXPANDED EAST INTO PARTS
OF LAKE HURON ON FRIDAY. MARGINAL SCA/S MAY AGAIN BE NECESSARY ON
SATURDAY GIVEN STRENGTHENING NORTHWEST FLOW.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...HEAT ADVISORY UNTIL 8 AM EDT FRIDAY FOR MIZ016>034.
HEAT ADVISORY UNTIL 8 PM EDT FRIDAY FOR MIZ035-036-041-042.
LH...NONE.
LM...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 5 PM EDT FRIDAY
FOR LMZ323-342-344>346.
LS...NONE.
&&
$$
SYNOPSIS...JPB
SHORT TERM...ARNOTT
LONG TERM...JPB
AVIATION...ARNOTT
MARINE...ARNOTT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
209 PM EDT THU JUL 18 2013
.UPDATE...
ISSUED AT 1054 AM EDT THU JUL 18 2013
12Z SFC ANALYSIS SHOWS SFC LOW OVER CENTRAL ND WITH WARM FRONT
ARCING FROM FARGO TO JUST SOUTH OF DLH AND NEAR HYR. STATIONARY
FRONT PRETTY MUCH BISECTS UPR MICHIGAN FROM NORTH TO SOUTH. MORE
OF A ONSHORE/MARINE INFLUENCE IS NOTED AT CMX/P59 AND TO MARQUETTE
VCNTY. CLUSTER OF SHOWERS/TSRA WITH HEAVY DOWNPOURS WORKING ACROSS
CNTRL UPR MICHIGAN AS OF 1430Z. NOT MUCH OCCURRING INTO SOUTHWEST
UPR MICHIGAN AND NORTHERN WI/CENTRAL MN. 12Z SOUNDINGS FM MPX AND
GRB SHOWED STEEP LAPSE RATES BUT CAPPING WAS NOT THAT STRONG.
CONVECTIVE TEMPS WERE AROUND 90 DEGREES. MAY SEE ISOLD-SCT SHRA/TSRA
FORM DURING PEAK HEATING BUT THERE MAY BE A BIT OF A LULL BTWN EARLY
AFTN AND LATE AFTN. BASED ON H85 TEMPS PUSHING 20C THIS AFTN AND
SHARP CLEARING OCCURRING BEHIND THIS INITIAL SHRA/TSRA...RAISED
TEMPS BACK TO AROUND 90 DEGREES FOR MUCH OF CWA...EVEN MID 90S
POSSIBLE OVER INTERIOR SCNTRL.
GIVEN DEGREE OF INSTABILITY /SBCAPES OVER 2000 J/KG DCAPES NEAR
1000J/KG/ AND INCREASING SHEAR /0-6KM SHEAR OVER 40 KTS PUSHING IN
FROM NORTHERN MN AHEAD OF STRONG SHORTWAVE MOVING ACROSS SOUTHERN
MANITOBA/ PER SPC MESOANALYSIS PAGE...IF STORMS DEVELOP THIS AFTN
DURING PEAK HEATING THEY WOULD LIKELY BECOME SEVERE. A SITUATION
WITH A CONDITIONAL PROBABILITY THOUGH AS THERE IS NOT MUCH OF A
TRIGGER IN THE LOW-LEVELS. SINCE THE STATIONARY FRONT IS OVERHEAD
AND BASED ON RAP FORECAST SOUNDINGS SHOWING SHARPLY CURVED HODOGRAPHS
AND SINCE 0-1KM SHEAR IS 25-30 KTS...STILL CANNOT RULE OUT ISOLD
TORNADO OCCURRING. LCL HEIGHTS ARE ON THE HIGHER SIDE THOUGH AND
MIGHT MITIGATE THAT RISK.
STILL APPEARS THAT ANOTHER ROUND OR TWO OF SHRA/TSRA ROLL ACROSS UPR
MICHIGAN THIS EVENING INTO TONIGHT ALONG THE SFC FRONT AND JUST AHEAD
OF STRONG COLD FRONT. POTENTIAL STILL THERE FOR STRONG WINDS AND HEAVY
RAIN. NO CHANGES MADE TO TONIGHT AT THIS POINT THOUGH.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 434 AM EDT THU JUL 18 2013
OTHER THAN SHORT TERM UPDATES...DID NOT CHANGE MUCH FROM THE
PREVIOUS FORECAST FOR TONIGHT/TONIGHT. SINCE THE CONVECTION THAT MAY
MOVE ACROSS THE CWA TODAY HAS NOT DEVELOPED...AND SINCE GUIDANCE HAS
NOT CHANGED MUCH IN THE LAST DAY OR SO...THERE WAS NO REASON TO
CHANGE THE FORECAST TOO MUCH. HEAVY RAIN CONTINUES TO BE THE MOST
OBVIOUS THREAT FROM CONVECTION TODAY...BUT LARGE HAIL AND DAMAGING
WINDS ARE ALSO POSSIBLE...AND A SMALL THREAT OF A TORNADO CAN NOT BE
RULED OUT COMPLETELY.
THE SYNOPTIC PATTERN FOR THE PERIOD HAS THE CWA BETWEEN A LOW OVER
HUDSON BAY AND A BROAD HIGH S OF THE GREAT LAKES. THE HIGH WILL
BREAK DOWN AND MOVE S WHILE PART OF THE LOW WILL BREAK OFF AND MOVE
INTO NRN SASK BY 12Z FRI.
STORMS HAVE BEEN FOCUSING ALONG A WEAK STATIONARY
BOUNDARY...COMBINED WITH THE NOCTURNAL LOW LEVEL JET...ACROSS THE
CWA SO FAR TODAY. A FEW OF THESE STORMS HAVE BEEN STRONGER...WITH
PLENTY OF MID LEVEL ROTATION...BUT NO LOW LEVEL ROTATION AND THEY
HAVE BEEN PRETTY PULSE LIKE. THINK THE BOUNDARY WILL STAY NEARLY
STATIONARY TODAY...PUTTING MUCH OF THE CWA IN THE WARM SECTOR AS
SWLY LOW LEVEL FLOW INCREASES AHEAD OF A SFC TROUGH/COLD FRONT THAT
WILL MOVE IN LATE TODAY/TONIGHT. MID/UPPER LEVEL FLOW WILL BE
PARALLEL TO THE FRONT...SO TRAINING PRECIP IS A GOOD BET.
ALSO...PWATS WILL BE 1.75-2.00 INCHES /180-200 PERCENT OF
NORMAL/...SO MOISTURE WILL BE PREVALENT. EXACT LOCATION OF HEAVIER
PRECIP WILL DEPEND ON TRACK OF THUNDERSTORMS AND WHERE THE BOUNDARY
/THAT WILL BE CONVECTIVELY ENHANCED/ WILL BE...SO IT IS IMPOSSIBLE
TO PREDICT WITH ANY GREAT ACCURACY BEFORE THE STORMS HAVE FORMED.
DID ADD HEAVY RAINFALL ATTRIBUTE TO WEATHER GRIDS FOR TODAY/TONIGHT.
WITH HIGH TEMPS OF AROUND 80F TO 90F TODAY...AND PLENTY OF
MOISTURE...INSTABILITY WILL BE PRETTY GOOD. MLCAPES OF 1500J/KG TO
JUST OVER 2000J/KG ARE FORECAST BY MODELS...WITH 0-6KM BULK SHEAR OF
30-40KTS. MOST OF THAT SHEAR WILL BE UNIDIRECTIONAL...BUT SOME
VEERING WITH HEIGHT IS MODELED IN THE LOW LEVELS. MAIN STORM MODE
SHOULD BE SINGLE CELL OR MULTICELL CLUSTERS WITH SOME CHANCE OF SOME
SUPERCELL ACTIVITY. THE CAPE/SHEAR COMBINED WITH DRY VERY LOW LEVELS
/MIXING LAYER/ WILL MAKE FOR A WIND DAMAGE THREAT THIS AFTERNOON AS
DCAPE VALUES APPROACH 1000J/KG. LARGE HAIL WILL ALSO BE A THREAT.
TORNADO THREAT IS MINIMAL...BUT CAN NOT BE COMPLETELY RULED OUT WITH
MORE SIGNIFICANT STORM/BOUNDARY INTERACTIONS.
FOR TONIGHT...MAIN CONCERN...SEVERE WEATHER WISE...IS FOR HIGH WINDS
ASSOCIATED WITH A POSSIBLE MCS MOVING THROUGH OR NEAR THE CWA.
MODELS HAVE BEEN PERSISTENT WITH BRINGING A CONVECTIVE CLUSTER
ACROSS THE CWA...FOLLOWING THE MEAN FLOW...CAPE GRADIENT AND THE
FRONT. EVEN THOUGH A NEAR SFC INVERSION SHOULD FORM...AN EML WILL
STAY OVER THE CWA...SO LOW LEVELS WILL REMAIN DRY...WHICH SHOULD
HELP COLD POOL PROCESSES AND INCREASE THE WIND THREAT. ALSO...THAT
SFC TROUGH/COLD FRONT WILL MOVE INTO THE CWA WITH UPPER LEVEL HEIGHT
FALLS AS THE UPPER LEVEL TROUGH APPROACHES THE CWA. WITH THE UPPER
TROUGH MOVING SOUTH...THE CWA WILL COME UNDER THE RIGHT ENTRANCE
REGION OF AN UPPER LEVEL JET...ALSO PROMOTING PRECIP. HEAVY RAIN
POTENTIAL DEFINITELY CONTINUES INTO TONIGHT...JUST A MATTER OF
EXACTLY WHERE THAT MAY HAPPEN.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 434 AM EDT THU JUL 18 2013
FRI...AS UPR TROF CENTERED OVER HUDSON BAY DEEPENS INTO ONTARIO...
COLD FNT MOVING INTO WRN UPR MI ARND SUNRISE ON FRI WL MOVE TO THE
SE OF THE CWA IN THE AFTN. WITH THE ARRIVAL OF DRIER AIR/VIGOROUS
NEGATIVE H85 THETA E ADVECTION...LINGERING SHRA/TS WL END NW TO
SE...BUT GOING LIKELY POPS OVER THE SE CWA IN THE MRNG SEEM
APPROPRIATE. STEEPENING MID LVL LAPSE RATES MAY MAINTAIN POPS OVER
MAINLY THE SCENTRAL FOR A LONGER TIME...BUT THE SHARP DRYING ALF WL
ACT TO LIMIT THIS POTENTIAL. THE RETURN OF MORE AFTN SUNSHINE...H85
TEMPS AS HI AS 17C AT 00Z SAT...AND DOWNSLOPING WNW FLOW WL HELP
BOOST MAX TEMPS OVER THE SCENTRL WELL INTO THE 80S TO NEAR 90. THE
NW FLOW OFF LK SUP WL BRING COOLER WX TO THE W.
FRI NGT INTO SAT...MODELS INDICATE A REINFORCING SHRTWV/SECONDARY
COLD FNT WL SWEEP THRU THE UPR LKS. IN FACT...THE 00Z NAM SHOWS MORE
SGNFT DPVA/QVECTOR CNVGC AND GENERATES SOME PCPN LATE FRI NGT/EARLY
SAT. THE 00Z GFS/12Z ECMWF SHOW MORE DEEP LYR QVECTOR DVGC/A WEAKER
SFC REFLECTION/FNT WITH DRY AIR DOMINATING. SINCE THE DISTURBANCE/
FNT WL BE ARRIVING AT MIN DIURNAL HEATING TIME WITH AN ABSENCE OF
ANY MOISTENING AT H85...OPTED TO MAINTAIN GOING DRY FCST AND JUST
ADD MORE CLDS TO THE FCST. THESE CLDS WL
LATER SAT INTO SUN...UNDER CONFLUENT NW FLOW ALF...CNDN HI PRES IS
FCST TO BUILD OVER LK SUP SAT EVNG AND DRIFT ONLY SLOWLY SE TO OVER
LK HURON LATE SUN. WITH THE ARRIVAL OF MUCH DRIER AIR /PWAT FCST TO
REACH CLOSE TO 0.50 INCH BY 12Z SUN/...EXPECT MOCLR CONDITIONS. A
STEADY N WIND OFF LK SUP WL LIMIT THE DIURNAL TEMP RECOVERY ON
SAT... ESPECIALLY NEAR THE SHORE. OVERNGT LOWS ON SAT NGT WL FALL
SHARPLY INTO THE 40S OVER THE COOLER INTERIOR LOCATIONS EARLY SUN
MRNG WITH LIGHT WINDS. WITH H85 TEMPS PROGGED NEAR 10C LATER
SUN...EXPECT DAYTIME MAX TEMPS TO RISE INTO THE 70S AWAY THE
MODERATING INFLUENCE OF THE GREAT LKS AS RELATIVELY WEAK PRES
GRADIENT ALLOWS LK BREEZES TO FORM OFF ALL THE LKS.
EXTENDED...AS IS OFTEN THE CASE IN SUMMER...MODELS HAVE SHOWN
CONSIDERABLE INCONSISTENCIES IN THE HANDLING OF SHRTWVS EMBEDDED IN
WNW FLOW ALF EARLY NEXT WEEK. SOME OF THE MOST PROGRESSIVE GUIDANCE
INDICATES SOME PCPN MAY REACH THE WRN CWA AS EARLY AS LATE SUN.
CONSIDERING THE CONSIDERABLE INCONSISTENCY IN A RELATIVELY
UNPREDICTABLE PATTERN...OPTED TO MAINTAIN THE MODEL CONSENSUS FCST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 159 PM EDT THU JUL 18 2013
SCT TSRA DEVELOPING SCNTRL MAY IMPACT SAW THROUGH MID AFTN. ADDITIONAL
TSRA MAY AFFECT IWD THOUGH THEY MAY END UP JUST EAST OF THAT SITE.
VFR CONDITIONS EXPECTED...BUT HEAVY DOWNPOURS AND STRONG WIND GUSTS
MAY OCCUR. ADDITIONAL TSRA POSSIBLE TONIGHT AS COMPLEX OF SHRA/TSRA
FORMING OVER NORTHERN MN ROLL ESE THROUGH THE EVENING AND OVERNIGHT
HOURS. MAIN HAZARD WITH THESE STORMS WILL BE GUSTY WINDS AND HEAVY
RAIN. EXPECT PRECIP TO END AROUND DAYBREAK ON FRIDAY. MAIN ISSUE FOR
MOST OF FRIDAY WILL BE GUSTY WNW WINDS...ESPECIALLY AT MORE EXPOSED
CMX LOCATION WHERE WIND GUSTS COULD REACH OVER 20 KTS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 434 AM EDT THU JUL 18 2013
WITH RELATIVELY WEAK PRES GRADIENT AND HI STABILITY OVER THE
RELATIVELY COOL LAKE WATERS...EXPECT WINDS NO HIGHER THAN 20 KTS
THIS FORECAST PERIOD. THE MAIN WEATHER CONCERN WILL BE FOG WITH A
HUMID AIRMASS DOMINATING. THIS FOG IS LIKELY TO BE MOST WIDESPREAD
TONIGHT FOLLOWING SOME STRONG TO POSSIBLY SEVERE THUNDERSTORMS
THAT WILL FURTHER SATURATE THE MARINE LAYER. THE ARRIVAL OF DRIER
AIR BEHIND A COLD FRONTAL PASSAGE ON FRI SHOULD DISSIPATE THE FOG.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...JLA
SHORT TERM...TITUS
LONG TERM...KC
AVIATION...JLA
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1104 AM EDT THU JUL 18 2013
.UPDATE...
ISSUED AT 1054 AM EDT THU JUL 18 2013
12Z SFC ANALYSIS SHOWS SFC LOW OVER CENTRAL ND WITH WARM FRONT
ARCING FROM FARGO TO JUST SOUTH OF DLH AND NEAR HYR. STATIONARY
FRONT PRETTY MUCH BISECTS UPR MICHIGAN FROM NORTH TO SOUTH. MORE
OF A ONSHORE/MARINE INFLUENCE IS NOTED AT CMX/P59 AND TO MARQUETTE
VCNTY. CLUSTER OF SHOWERS/TSRA WITH HEAVY DOWNPOURS WORKING ACROSS
CNTRL UPR MICHIGAN AS OF 1430Z. NOT MUCH OCCURRING INTO SOUTHWEST
UPR MICHIGAN AND NORTHERN WI/CENTRAL MN. 12Z SOUNDINGS FM MPX AND
GRB SHOWED STEEP LAPSE RATES BUT CAPPING WAS NOT THAT STRONG.
CONVECTIVE TEMPS WERE AROUND 90 DEGREES. MAY SEE ISOLD-SCT SHRA/TSRA
FORM DURING PEAK HEATING BUT THERE MAY BE A BIT OF A LULL BTWN EARLY
AFTN AND LATE AFTN. BASED ON H85 TEMPS PUSHING 20C THIS AFTN AND
SHARP CLEARING OCCURRING BEHIND THIS INITIAL SHRA/TSRA...RAISED
TEMPS BACK TO AROUND 90 DEGREES FOR MUCH OF CWA...EVEN MID 90S
POSSIBLE OVER INTERIOR SCNTRL.
GIVEN DEGREE OF INSTABILITY /SBCAPES OVER 2000 J/KG DCAPES NEAR
1000J/KG/ AND INCREASING SHEAR /0-6KM SHEAR OVER 40 KTS PUSHING IN
FROM NORTHERN MN AHEAD OF STRONG SHORTWAVE MOVING ACROSS SOUTHERN
MANITOBA/ PER SPC MESOANALYSIS PAGE...IF STORMS DEVELOP THIS AFTN
DURING PEAK HEATING THEY WOULD LIKELY BECOME SEVERE. A SITUATION
WITH A CONDITIONAL PROBABILITY THOUGH AS THERE IS NOT MUCH OF A
TRIGGER IN THE LOW-LEVELS. SINCE THE STATIONARY FRONT IS OVERHEAD
AND BASED ON RAP FORECAST SOUNDINGS SHOWING SHARPLY CURVED HODOGRAPHS
AND SINCE 0-1KM SHEAR IS 25-30 KTS...STILL CANNOT RULE OUT ISOLD
TORNADO OCCURRING. LCL HEIGHTS ARE ON THE HIGHER SIDE THOUGH AND
MIGHT MITIGATE THAT RISK.
STILL APPEARS THAT ANOTHER ROUND OR TWO OF SHRA/TSRA ROLL ACROSS UPR
MICHIGAN THIS EVENING INTO TONIGHT ALONG THE SFC FRONT AND JUST AHEAD
OF STRONG COLD FRONT. POTENTIAL STILL THERE FOR STRONG WINDS AND HEAVY
RAIN. NO CHANGES MADE TO TONIGHT AT THIS POINT THOUGH. &&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 434 AM EDT THU JUL 18 2013
OTHER THAN SHORT TERM UPDATES...DID NOT CHANGE MUCH FROM THE
PREVIOUS FORECAST FOR TONIGHT/TONIGHT. SINCE THE CONVECTION THAT MAY
MOVE ACROSS THE CWA TODAY HAS NOT DEVELOPED...AND SINCE GUIDANCE HAS
NOT CHANGED MUCH IN THE LAST DAY OR SO...THERE WAS NO REASON TO
CHANGE THE FORECAST TOO MUCH. HEAVY RAIN CONTINUES TO BE THE MOST
OBVIOUS THREAT FROM CONVECTION TODAY...BUT LARGE HAIL AND DAMAGING
WINDS ARE ALSO POSSIBLE...AND A SMALL THREAT OF A TORNADO CAN NOT BE
RULED OUT COMPLETELY.
THE SYNOPTIC PATTERN FOR THE PERIOD HAS THE CWA BETWEEN A LOW OVER
HUDSON BAY AND A BROAD HIGH S OF THE GREAT LAKES. THE HIGH WILL
BREAK DOWN AND MOVE S WHILE PART OF THE LOW WILL BREAK OFF AND MOVE
INTO NRN SASK BY 12Z FRI.
STORMS HAVE BEEN FOCUSING ALONG A WEAK STATIONARY
BOUNDARY...COMBINED WITH THE NOCTURNAL LOW LEVEL JET...ACROSS THE
CWA SO FAR TODAY. A FEW OF THESE STORMS HAVE BEEN STRONGER...WITH
PLENTY OF MID LEVEL ROTATION...BUT NO LOW LEVEL ROTATION AND THEY
HAVE BEEN PRETTY PULSE LIKE. THINK THE BOUNDARY WILL STAY NEARLY
STATIONARY TODAY...PUTTING MUCH OF THE CWA IN THE WARM SECTOR AS
SWLY LOW LEVEL FLOW INCREASES AHEAD OF A SFC TROUGH/COLD FRONT THAT
WILL MOVE IN LATE TODAY/TONIGHT. MID/UPPER LEVEL FLOW WILL BE
PARALLEL TO THE FRONT...SO TRAINING PRECIP IS A GOOD BET.
ALSO...PWATS WILL BE 1.75-2.00 INCHES /180-200 PERCENT OF
NORMAL/...SO MOISTURE WILL BE PREVALENT. EXACT LOCATION OF HEAVIER
PRECIP WILL DEPEND ON TRACK OF THUNDERSTORMS AND WHERE THE BOUNDARY
/THAT WILL BE CONVECTIVELY ENHANCED/ WILL BE...SO IT IS IMPOSSIBLE
TO PREDICT WITH ANY GREAT ACCURACY BEFORE THE STORMS HAVE FORMED.
DID ADD HEAVY RAINFALL ATTRIBUTE TO WEATHER GRIDS FOR TODAY/TONIGHT.
WITH HIGH TEMPS OF AROUND 80F TO 90F TODAY...AND PLENTY OF
MOISTURE...INSTABILITY WILL BE PRETTY GOOD. MLCAPES OF 1500J/KG TO
JUST OVER 2000J/KG ARE FORECAST BY MODELS...WITH 0-6KM BULK SHEAR OF
30-40KTS. MOST OF THAT SHEAR WILL BE UNIDIRECTIONAL...BUT SOME
VEERING WITH HEIGHT IS MODELED IN THE LOW LEVELS. MAIN STORM MODE
SHOULD BE SINGLE CELL OR MULTICELL CLUSTERS WITH SOME CHANCE OF SOME
SUPERCELL ACTIVITY. THE CAPE/SHEAR COMBINED WITH DRY VERY LOW LEVELS
/MIXING LAYER/ WILL MAKE FOR A WIND DAMAGE THREAT THIS AFTERNOON AS
DCAPE VALUES APPROACH 1000J/KG. LARGE HAIL WILL ALSO BE A THREAT.
TORNADO THREAT IS MINIMAL...BUT CAN NOT BE COMPLETELY RULED OUT WITH
MORE SIGNIFICANT STORM/BOUNDARY INTERACTIONS.
FOR TONIGHT...MAIN CONCERN...SEVERE WEATHER WISE...IS FOR HIGH WINDS
ASSOCIATED WITH A POSSIBLE MCS MOVING THROUGH OR NEAR THE CWA.
MODELS HAVE BEEN PERSISTENT WITH BRINGING A CONVECTIVE CLUSTER
ACROSS THE CWA...FOLLOWING THE MEAN FLOW...CAPE GRADIENT AND THE
FRONT. EVEN THOUGH A NEAR SFC INVERSION SHOULD FORM...AN EML WILL
STAY OVER THE CWA...SO LOW LEVELS WILL REMAIN DRY...WHICH SHOULD
HELP COLD POOL PROCESSES AND INCREASE THE WIND THREAT. ALSO...THAT
SFC TROUGH/COLD FRONT WILL MOVE INTO THE CWA WITH UPPER LEVEL HEIGHT
FALLS AS THE UPPER LEVEL TROUGH APPROACHES THE CWA. WITH THE UPPER
TROUGH MOVING SOUTH...THE CWA WILL COME UNDER THE RIGHT ENTRANCE
REGION OF AN UPPER LEVEL JET...ALSO PROMOTING PRECIP. HEAVY RAIN
POTENTIAL DEFINITELY CONTINUES INTO TONIGHT...JUST A MATTER OF
EXACTLY WHERE THAT MAY HAPPEN.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 434 AM EDT THU JUL 18 2013
FRI...AS UPR TROF CENTERED OVER HUDSON BAY DEEPENS INTO ONTARIO...
COLD FNT MOVING INTO WRN UPR MI ARND SUNRISE ON FRI WL MOVE TO THE
SE OF THE CWA IN THE AFTN. WITH THE ARRIVAL OF DRIER AIR/VIGOROUS
NEGATIVE H85 THETA E ADVECTION...LINGERING SHRA/TS WL END NW TO
SE...BUT GOING LIKELY POPS OVER THE SE CWA IN THE MRNG SEEM
APPROPRIATE. STEEPENING MID LVL LAPSE RATES MAY MAINTAIN POPS OVER
MAINLY THE SCENTRAL FOR A LONGER TIME...BUT THE SHARP DRYING ALF WL
ACT TO LIMIT THIS POTENTIAL. THE RETURN OF MORE AFTN SUNSHINE...H85
TEMPS AS HI AS 17C AT 00Z SAT...AND DOWNSLOPING WNW FLOW WL HELP
BOOST MAX TEMPS OVER THE SCENTRL WELL INTO THE 80S TO NEAR 90. THE
NW FLOW OFF LK SUP WL BRING COOLER WX TO THE W.
FRI NGT INTO SAT...MODELS INDICATE A REINFORCING SHRTWV/SECONDARY
COLD FNT WL SWEEP THRU THE UPR LKS. IN FACT...THE 00Z NAM SHOWS MORE
SGNFT DPVA/QVECTOR CNVGC AND GENERATES SOME PCPN LATE FRI NGT/EARLY
SAT. THE 00Z GFS/12Z ECMWF SHOW MORE DEEP LYR QVECTOR DVGC/A WEAKER
SFC REFLECTION/FNT WITH DRY AIR DOMINATING. SINCE THE DISTURBANCE/
FNT WL BE ARRIVING AT MIN DIURNAL HEATING TIME WITH AN ABSENCE OF
ANY MOISTENING AT H85...OPTED TO MAINTAIN GOING DRY FCST AND JUST
ADD MORE CLDS TO THE FCST. THESE CLDS WL
LATER SAT INTO SUN...UNDER CONFLUENT NW FLOW ALF...CNDN HI PRES IS
FCST TO BUILD OVER LK SUP SAT EVNG AND DRIFT ONLY SLOWLY SE TO OVER
LK HURON LATE SUN. WITH THE ARRIVAL OF MUCH DRIER AIR /PWAT FCST TO
REACH CLOSE TO 0.50 INCH BY 12Z SUN/...EXPECT MOCLR CONDITIONS. A
STEADY N WIND OFF LK SUP WL LIMIT THE DIURNAL TEMP RECOVERY ON
SAT... ESPECIALLY NEAR THE SHORE. OVERNGT LOWS ON SAT NGT WL FALL
SHARPLY INTO THE 40S OVER THE COOLER INTERIOR LOCATIONS EARLY SUN
MRNG WITH LIGHT WINDS. WITH H85 TEMPS PROGGED NEAR 10C LATER
SUN...EXPECT DAYTIME MAX TEMPS TO RISE INTO THE 70S AWAY THE
MODERATING INFLUENCE OF THE GREAT LKS AS RELATIVELY WEAK PRES
GRADIENT ALLOWS LK BREEZES TO FORM OFF ALL THE LKS.
EXTENDED...AS IS OFTEN THE CASE IN SUMMER...MODELS HAVE SHOWN
CONSIDERABLE INCONSISTENCIES IN THE HANDLING OF SHRTWVS EMBEDDED IN
WNW FLOW ALF EARLY NEXT WEEK. SOME OF THE MOST PROGRESSIVE GUIDANCE
INDICATES SOME PCPN MAY REACH THE WRN CWA AS EARLY AS LATE SUN.
CONSIDERING THE CONSIDERABLE INCONSISTENCY IN A RELATIVELY
UNPREDICTABLE PATTERN...OPTED TO MAINTAIN THE MODEL CONSENSUS FCST.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 742 AM EDT THU JUL 18 2013
THE MAIN FOCUS OF CONCERN FOR THIS FORECAST PERIOD WILL BE
THUNDERSTORM DEVELOPMENT ALONG/NEAR THE COLD FRONT ACROSS UPPER
MICHIGAN. EXPECT A DECREASE IN SHOWER AND THUNDERSTORM COVERAGE LATE
THIS MORNING INTO THIS AFTERNOON. TOUGH TO PIN POINT ANY EXACT
TIMING FOR THE STORMS...BUT THE EXPECTATION IS THAT ANY STORM WILL
CREATE TORRENTIAL DOWNPOURS AND BRIEF IFR CONDITIONS. THE NEXT ROUND
OF PRECIP DEVELOPS LATE THIS AFTN INTO TONIGHT. THESE COULD END UP
BEING STRONG TO SEVERE ESPECIALLY IF THEY DEVELOP INTO A ORGANIZED
CONVECTIVE COMPLEX.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 434 AM EDT THU JUL 18 2013
WITH RELATIVELY WEAK PRES GRADIENT AND HI STABILITY OVER THE
RELATIVELY COOL LAKE WATERS...EXPECT WINDS NO HIGHER THAN 20 KTS
THIS FORECAST PERIOD. THE MAIN WEATHER CONCERN WILL BE FOG WITH A
HUMID AIRMASS DOMINATING. THIS FOG IS LIKELY TO BE MOST WIDESPREAD
TONIGHT FOLLOWING SOME STRONG TO POSSIBLY SEVERE THUNDERSTORMS
THAT WILL FURTHER SATURATE THE MARINE LAYER. THE ARRIVAL OF DRIER
AIR BEHIND A COLD FRONTAL PASSAGE ON FRI SHOULD DISSIPATE THE FOG.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...JLA
SHORT TERM...TITUS
LONG TERM...KC
AVIATION...TITUS
MARINE...KC
AREA FORECAST DISCUSSION
NWS DULUTH MN
304 PM CDT THU JUL 18 2013
.SHORT TERM.../THROUGH TONIGHT/
THE FOCUS IS ON THE THREAT OF SEVERE THUNDERSTORMS THROUGH THIS
EVENING. THE STORM PREDICTION CENTER HAS POSTED ALL OF THE
NORTHLAND IN AT LEAST A SLIGHT RISK OF SEVERE THUNDERSTORMS...AND
A MODERATE RISK ACROSS THE SOUTHERN HALF OF THE FORECAST AREA.
LARGE HAIL AND HEAVY RAIN MAY BE THE INITIAL MAIN THREATS AND THEN
QUICKLY TRANSITIONING TO A DAMAGING WIND THREAT. THE
MODELS...ESPECIALLY THE HIGH RESOLUTION HRRR AND NCEP WRF
SIMULATED REFLECTIVITY RUNS...HAVE BEEN INDICATING SUPERCELL
THUNDERSTORMS WILL LIKELY DEVELOP IN NW AND NORTH CENTRAL
MINNESOTA LATE THIS AFTERNOON OR EARLY THIS EVENING...AND THEN
CONGEAL INTO A LINE OF STORMS THAT SWEEP THROUGH THE NORTHLAND
THIS EVENING. A SEVERE THUNDERSTORM WATCH WILL LIKELY BE ISSUED
WITHIN THE NEXT HOUR OR SO.
THIS AFTERNOON AND EVENING...MUCH OF THE NORTHLAND HAS HOT AND
MUGGY WEATHER WITH GUSTY SW WINDS AS A FRONT STRETCHES ACROSS
WESTERN ONTARIO TO A LOW IN THE NORTHERN RED RIVER VALLEY. A
STRONG COLD FRONT EXTENDS FROM SW FROM THE LOW THROUGH THE CENTRAL
DAKOTAS. MOST OF THE NORTHLAND...SAVE FOR THE FAR NORTH AND OVER
THE LAKE...HAS DEVELOPED AMPLE SURFACE BASED CAPE UP TO AROUND
3500 J/KG...MAXIMIZED ACROSS THE S AND SW FORECAST AREA. THERE IS
LITTLE IF ANY INHIBITION. DEEP LAYER (0-6KM) WIND SHEAR OF 30 TO
50 KNOTS HAS DEVELOPED...WITH THE HIGHEST SHEAR ACROSS THE
NORTHERN HALF OF THE FORECAST AREA. PRECIPITABLE WATER VALUES ARE
AROUND 1.75 TO 2 INCHES. THERE SHOULD BE INCREASING CHANCES OF
SHOWERS AND STORMS ACROSS THE FORECAST AREA THROUGH THE REST OF
THE AFTERNOON...BUT THE FOCUS WILL BE ON THE WESTERN FORECAST AREA
WHERE THE MODELS HAVE BEEN INDICATING THUNDERSTORMS...LIKELY AT
FIRST SUPERCELLS...WILL DEVELOP IN NW AND NORTH CENTRAL MINNESOTA
LATE THIS AFTERNOON NEAR THE LOW PRESSURE SYSTEM AND APPROACHING
COLD FRONT. CONSIDERING THE AVAILABLE CAPE...CAPE SOUNDING
PROFILES...AND DEEP LAYER WINDS...THE SUPERCELLS COULD EASILY
DEVELOP LARGE HAIL...GUSTY WINDS...AND HEAVY RAIN. A STRAY TORNADO
CANNOT BE RULED OUT. THE STORMS MAY QUICKLY CONGEAL...AS THE
MODELS SUGGEST...INTO A LINE OF STORMS WITH A TRANSITIONING THREAT
TO MAINLY DAMAGING WINDS AND HEAVY RAIN. THIS LINE AND COLD FRONT
COULD SWEEP ESE THROUGH THE REST OF NE MINNESOTA AND THEN NW
WISCONSIN PRETTY QUICKLY THIS EVENING. I ADDED WORDING TO THE
FORECAST TO INCLUDE SEVERE THUNDERSTORMS AND THE LIKELY THREATS
FOR WHEREVER MY PCPN CHANCES ARE LIKELY LATE THIS AFTERNOON
THROUGH AROUND MIDNIGHT...WHICH IS BASICALLY MY BEST GUESS ON THE
HOURLY TIMING OF THE MAIN LINE OF THUNDERSTORMS.
LATE TONIGHT...THE SEVERE WEATHER THREAT SHOULD COME TO AN END
AROUND MIDNIGHT AS THE MAIN LINE OF STORMS MOVES SE OF THE
FORECAST AREA...BUT THERE COULD BE SOME LINGERING SHOWERS AND
STORMS ACROSS THE SE FORECAST AREA NEAR THE FRONT. THERE SHOULD
ALSO BE DECREASING CHANCES OF SHOWERS AND STORMS FROM NW TO
SE...BUT I LEFT LOW CHANCES OF SHOWERS AND STORMS ACROSS MOST OF
THE FORECAST AREA SINCE A SHORTWAVE WILL LIKELY MOVE INTO THE
NORTHERN FORECAST AREA LATE TONIGHT. THIS SHORTWAVE COULD HELP
DEVELOP SOME MORE SHOWERS AND STORMS.
.LONG TERM.../FRIDAY - WEDNESDAY/
THE WEST-NORTHWEST FLOW OF COOLER AND DRIER AIR WILL BE
ESTABLISHED OVER THE FORECAST AREA BY FRIDAY MIDDAY. THERE WILL
BE SOME LINGERING SHOWERS LEFT OVER FRIDAY MORNING BEFORE ENDING
BY MIDDAY. THE WEST TO NORTHWEST FLOW WILL CONTINUE INTO SATURDAY
BUT A WEAK SHORTWAVE WILL CAUSE A POSSIBILITY OF SHOWERS ACROSS
THE REGION. THE RIDGE WILL MOVE EAST AND A RETURN FLOW OF MOISTURE
TO THE FORECAST AREA ON SUNDAY. THIS WILL CONTINUE INTO MIDWEEK
WITH WEAK SHORTWAVES PASSING THROUGH THE FLOW. THIS WILL KEEP A
CHANCE FOR PRECIP ACROSS THE FORECAST AREA FOR THE TIME PERIOD.
TEMPS WILL BE NEAR NORMAL THROUGH MOST OF THE WEEK.
&&
.AVIATION.../18Z TAF ISSUANCE/
VFR CONDITIONS WILL BE COMMON AT ALL TAFS SITES THIS AFTERNOON
EXCEPT FOR MVFR-IFR CIGS IN THUNDERSTORMS AT INL. A LINE OF STRONG
TO SEVERE THUNDERSTORMS WILL DEVELOP ALONG THE INTERNATIONAL
BORDER LATE THIS AFTERNOON AND MOVE SOUTHEAST TONIGHT ACROSS THE
TAF SITES. CIGS/VSBYS MAY DROP TO MVFR-IFR WITH LIFR CIGS POSSIBLE
IN THUNDERSTORMS. CONDITIONS WILL IMPROVE AFTER THE LINE PASSES
LATE TONIGHT AT ALL SITES. ON FRIDAY...VFR CONDITIONS WILL BE
COMMON AT ALL SITES.
&&
.POINT TEMPS/POPS...
DLH 65 78 52 70 / 60 20 10 10
INL 61 75 46 69 / 70 20 10 10
BRD 69 81 55 75 / 60 20 10 10
HYR 71 83 53 75 / 60 30 10 10
ASX 68 78 52 69 / 60 30 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...GROCHOCINSKI
LONG TERM....STEWART
AVIATION...STEWART
AREA FORECAST DISCUSSION
NWS DULUTH MN
104 PM CDT THU JUL 18 2013
.UPDATE...
THE STORM PREDICTION CENTER ISSUED A MODERATE RISK FOR A LARGE
PORTION OF THE FORECAST...MAINLY THE SOUTHERN HALF...FOR TODAY. I
UPDATED THE FORECAST THROUGH TONIGHT TO REFLECT THE BEST GUESS OF
THE TIMING AT WHICH THE EXPECTED LINE OF STORMS WILL FORM IN NW
AND NORTH CENTRAL MINNESOTA LATE THIS AFTERNOON AND THEN SWEEP
ACROSS THE NORTHLAND THROUGH THIS EVENING. THE LATEST 12Z NCEP WRF
AND RECENT HRRR REFLECTIVITY RUNS SEEM PRETTY GOOD WITH LOCATION
AND TIMING. I ALSO RAMPED UP THE WORDING IN THE HOURLY FORECAST
THROUGH THIS EVENING TO ADD WORDING THAT INCLUDED POSSIBLE SEVERE
THUNDERSTORMS...LARGE HAIL...DAMAGING WINDS...AND HEAVY RAIN FOR
WHERE I HAVE LIKELY PCPN CHANCES.
&&
.AVIATION.../18Z TAF ISSUANCE/
VFR CONDITIONS WILL BE COMMON AT ALL TAFS SITES THIS AFTERNOON
EXCEPT FOR MVFR-IFR CIGS IN THUNDERSTORMS AT INL. A LINE OF STRONG
TO SEVERE THUNDERSTORMS WILL DEVELOP ALONG THE INTERNATIONAL
BORDER LATE THIS AFTERNOON AND MOVE SOUTHEAST TONIGHT ACROSS THE
TAF SITES. CIGS/VSBYS MAY DROP TO MVFR-IFR WITH LIFR CIGS POSSIBLE
IN THUNDERSTORMS. CONDITIONS WILL IMPROVE AFTER THE LINE PASSES
LATE TONIGHT AT ALL SITES. ON FRIDAY...VFR CONDITIONS WILL BE
COMMON AT ALL SITES.
&&
.PREV DISCUSSION... /ISSUED 1021 AM CDT THU JUL 18 2013/
UPDATE...
THE FOCUS WITH THIS UPDATE IS CONVEYING THE CURRENT TRENDS OF
SHOWERS AND STORMS LATE THIS MORNING...HOW THE ACTIVITY WILL
EVOLVE THIS AFTERNOON...AND CONVEYING THE THREAT/TIMING OF LIKELY
SEVERE WEATHER ACROSS THE WESTERN AND NORTHERN FORECAST AREA LATE
THIS AFTERNOON AND THIS EVENING. THE STORM PREDICTION CENTER STILL
HAS A SLIGHT RISK OF SEVERE STORMS ACROSS THE NORTHLAND FOR TODAY
AND TONIGHT...WITH AN ENHANCED RISK OF DAMAGING WINDS. THIS
ACTIVITY WILL LIKELY OCCUR IN THE VERY LATE AFTERNOON AND THIS
EVENING WHEN SUPERCELLS FORM IN NW AND FAR NORTH CENTRAL
MINNESOTA...THEN POSSIBLY CONGEAL TO FORM A LINE OF STORMS THAT
WILL SWEEP THROUGH THE NORTHLAND WITH DAMAGING WINDS THIS
EVENING. SURFACE BASED CAPE WILL LIKELY APPROACH...IF NOT
EXCEED...3000 J/KG...DEEP LAYER SHEAR WILL BE AROUND 35 TO 45
KNOTS...AND PRECIPITABLE WATER VALUES WILL BE AROUND 1.75 TO 2
INCHES...SO THE THREAT OF LARGE HAIL AND HEAVY RAIN IS THERE TOO.
SHOWERS AND STORMS HAVE BEEN RIDING EAST ALONG THE INTERNATIONAL
BORDER THIS MORNING. IT APPEARS THIS TREND WILL CONTINUE THROUGH
AT LEAST EARLY THIS AFTERNOON BEFORE PERHAPS SUBSIDING A BIT
DURING THE MID AFTERNOON. I AM LEANING ON THE LATEST HRRR AND 00Z
NCEP WRF SIMULATED REFLECTIVITY...AS WELL AS THE 12Z NAM...FOR MY
FORECAST THROUGH TONIGHT. THESE MODELS CAPTURE THE LULL IN
ACTIVITY DURING THE MID AFTERNOON...THEN SHOWING A LINE OF
THUNDERSTORMS FORMING EITHER LATE THIS AFTERNOON OR EARLY THIS
EVENING NEAR THE WESTERN FORECAST AREA. I AM LIKING THIS IDEA. I
AT LEAST LEFT LOW PCPN CHANCES ACROSS THE ENTIRE FORECAST THROUGH
THIS AFTERNOON DUE TO THE LACK OF INHIBITION...SO I CANNOT RULE
OUT A SHOWER/STORM HERE AND THERE. THE LINE OF STRONG/SEVERE
STORMS LATE THIS AFTERNOON AND EARLY THIS EVENING SHOULD THEN MOVE
EAST AND SOUTH THROUGH THIS EVENING. I ADDED SEVERE WORDING TO THE
FORECAST ACROSS THE NORTHERN AND WESTERN FORECAST AREA. I MIGHT
HAVE TO ADD MORE WORDING WITH A LATER UPDATE...LIKE THE THREAT OF
DAMAGING WINDS...HEAVY RAIN...AND LARGE HAIL.
I ALSO INCREASED WINDS ACROSS THE SOUTHERN HALF OF THE FORECAST
AREA THROUGH THIS AFTERNOON. THE LATEST NAM12 AND SOUNDINGS
INDICATE PRETTY GOOD MIXING...SO I WOULD NOT BE SURPRISED IF SOME
AREAS SEE GUSTS IN THE 25 TO 30 MPH RANGE. I KEPT THE TEMPERATURE
FORECAST IN THE UPPER 80S AND LOW 90S...DESPITE SOME GUIDANCE
WANTING TO LOWER THE TEMPERATURES...BECAUSE THE SUNSHINE AND
MIXING SHOULD WARM UP THE SOUTHERN FORECAST AREA REALLY WELL. I
WOULD NOT BE SURPRISED IF I HAVE TO INCREASE THE TEMPERATURES EVEN
MORE DUE TO HOW QUICKLY THE SOUTH IS ALREADY WARMING THIS MORNING.
DUE TO THE HIGH HUMIDITY...THE HEAT INDICES WILL LIKELY REACH THE
95 TO 100 DEGREE RANGE ACROSS PARTS OF THE SOUTHERN HALF OF THE
FORECAST AREA THIS AFTERNOON. IT DOES NOT APPEAR THAT WE NEED A
HEAT ADVISORY AT THIS TIME...BUT SOME AREAS COULD BRIEFLY APPROACH
CRITERIA...WHICH IS A HEAT INDEX OF 100 DEGREES.
PREV DISCUSSION... /ISSUED 356 AM CDT THU JUL 18 2013/
STRONG/SEVERE STORMS EXPECTED LATER TODAY/TONIGHT...
SHORT TERM...STATIONARY FRONTAL BDRY ACROSS CWA ASSISTING WITH
CONTINUED GENERATION OF CONVECTION ACROSS NRN/CTRL TIER OF MN ZONES
EARLY THIS MORNING. INITIAL AREA OF STORMS MOVING EASTWARD OVER
WRN LAKE SUPERIOR WITH NEW DEVELOPMENT OCCURRING ACROSS NWRN KOOCH
COUNTY. FARTHER SOUTH CONVECTION NOT AS WIDESPREAD ALTHOUGH LATEST
INDICATIONS ON SPC MESOANALYSIS SHOWS DEVELOPING 85H FRONTOGENESIS
FROM ITASCA COUNTY TO SOUTH SHORE OF LAKE SUPERIOR. MAY SEE
INCREASE ALONG THIS CORRIDOR NEXT FEW HRS.
TODAY/TONIGHT...FRONTAL BDRY WILL ADVECT NORTH IN RESPONSE TO APPROACHING
COLD FRONT AND ASSOCIATED DEEPENING MID LVL SHORTWAVE. EXPECT WARM
FRONTOGENESIS TO ENHANCE AREA OF CONVECTION ACROSS THE CWA AS IT
LIFTS NORTH THIS MORNING. WELL ESTABLISHED WARM SECTOR SHOULD
COVER A LARGE PART OF CWA BY MIDDAY. THIS WILL YIELD MAX TEMPS
ABOVE GUIDANCE AGAIN WITH BRISK SWRLY FLOW IN BDRY LYR WITH
CONSIDERABLE GUSTS DURING THE AFTN AHEAD OF FRONT. GENERAL
CONSENSUS AMONG HI RES MDLS...ALBEIT SOME DIFFERENCES IN
TIMING...IS THAT AN INCREASINGLY INTENSE LINE OF CONVECTION WILL
ORGANIZE JUST WEST OF THE CWA MID/LATE AFTERNOON AND PLOW
SOUTHEASTWARD UNDER AMPLIFYING MID LVL TROF. SBCAPES AHEAD OF
FRONT WILL RANGE FROM 4000 TO 4500 J/KG AND EFFECTIVE SHEAR SHOULD
INCREASE TO 40/45KTS. THESE VALUES WILL GENERATE A LINE OF
STRONG/SVR STORMS WITH INCREASING POTENTIAL OF CONSIDERABLE WIND
DAMAGE AND HAIL. MAY SEE LINE EVOLVE INTO AN MCS AS IT RIDES SE
WITH SOME INDICATION IN DIFFLUENT THICKNESS FIELD THAT CORE OF
CONVECTION MAY TREND MORE SOUTH TOWARDS LWR ST CROIX VALLEY BY 12Z.
TOMORROW...INITIAL COLD FRONT WILL MOVE SOUTH OF CWA BY MID
MORNING. A SECONDARY FRONT...INDICATED IN LOW LVL THETAE
FIELDS...WILL MOVE ACROSS MN ZONES IN THE LATE MORNING/AFTN HRS.
GUSTY WINDS AND LOWERING HUMIDITY WILL RESULT HAVE KEPT INHERITED
DRY FCST FOR AFTN WITH IDEA THE SUFFICIENT MOISTURE WILL NOT BE
AVAILABLE BY AFTERNOON. SUSPECT THAT A FEW RW MAY TRY TO POP IN
AFTN INSTABILITY UNDER STEEPENING LAPSE RATES.
FRIDAY NIGHT THROUGH WEDNESDAY.
THIS FRIDAY NIGHT THROUGH WEDNESDAY TIME WILL FEATURE CHANCES FOR
SHOWERS/STORMS FOR MOST PERIODS...WITH A FAST WEST-NORTHWEST FLOW
ALOFT BRINGING PERIODIC SHORTWAVES THROUGH AND WITH A BAROCLINIC
ZONE REMAINING OVER/NEAR THE AREA.
COLD AIR ADVECTION WILL CONTINUE FRIDAY NIGHT AS HIGH PRESSURE
BUILDS INTO THE REGION. WE WENT DRY FRIDAY NIGHT...ALTHOUGH A FEW
MODELS SUGGEST SOME SHOWERS MAY LINGER INTO THE EVENING.
SEVERAL MODELS SHOW SOME LIGHT PRECIP POSSIBLE OVER OUR SOUTHERN CWA
ON SATURDAY DUE TO A WEAK WAVE AND TIGHT THERMAL GRADIENT. WE HAVE
SLIGHT CHANCE POPS ACROSS OUR SOUTHERN CWA BOTH SATURDAY AND
SATURDAY NIGHT.
THE SURFACE HIGH IS EXPECTED TO SLIDE EAST OF THE REGION SATURDAY
NIGHT INTO SUNDAY WITH A RETURN FLOW AND FAST WEST-NORTHWEST FLOW
ALOFT BRINGING FAST MOVING SHORTWAVES OVER/NEAR THE CWA. WE WILL
HAVE SMALL CHANCES FOR SHOWERS/STORMS OVER MUCH OF THE NORTHLAND
SUNDAY/SUNDAY NIGHT...ALTHOUGH THE PRECIP DOES NOT LOOK TO BE
PARTICULARLY WIDESPREAD OR HEAVY.
WE HAVE HIGHER POPS FOR MONDAY-TUESDAY AS A SURFACE LOW/FRONT
AFFECTS THE NORTHLAND.
WE EXPECT HIGHS SATURDAY IN THE UPPER SIXTIES TO MID
SEVENTIES...WITH THEM WARMING TO THE MID SEVENTIES TO LOWER EIGHTIES
BY MONDAY LASTING INTO WEDNESDAY.
&&
.POINT TEMPS/POPS...
DLH 65 78 52 70 / 60 20 10 10
INL 61 75 46 69 / 70 20 10 10
BRD 69 81 55 75 / 60 20 10 20
HYR 71 83 53 75 / 60 30 10 20
ASX 68 78 52 69 / 60 30 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...GROCHOCINSKI
LONG TERM....STEWART
AVIATION...STEWART
AREA FORECAST DISCUSSION
NWS DULUTH MN
1021 AM CDT THU JUL 18 2013
.UPDATE...
THE FOCUS WITH THIS UPDATE IS CONVEYING THE CURRENT TRENDS OF
SHOWERS AND STORMS LATE THIS MORNING...HOW THE ACTIVITY WILL
EVOLVE THIS AFTERNOON...AND CONVEYING THE THREAT/TIMING OF LIKELY
SEVERE WEATHER ACROSS THE WESTERN AND NORTHERN FORECAST AREA LATE
THIS AFTERNOON AND THIS EVENING. THE STORM PREDICTION CENTER STILL
HAS A SLIGHT RISK OF SEVERE STORMS ACROSS THE NORTHLAND FOR TODAY
AND TONIGHT...WITH AN ENHANCED RISK OF DAMAGING WINDS. THIS
ACTIVITY WILL LIKELY OCCUR IN THE VERY LATE AFTERNOON AND THIS
EVENING WHEN SUPERCELLS FORM IN NW AND FAR NORTH CENTRAL
MINNESOTA...THEN POSSIBLY CONGEAL TO FORM A LINE OF STORMS THAT
WILL SWEEP THROUGH THE NORTHLAND WITH DAMAGING WINDS THIS
EVENING. SURFACE BASED CAPE WILL LIKELY APPROACH...IF NOT
EXCEED...3000 J/KG...DEEP LAYER SHEAR WILL BE AROUND 35 TO 45
KNOTS...AND PRECIPITABLE WATER VALUES WILL BE AROUND 1.75 TO 2
INCHES...SO THE THREAT OF LARGE HAIL AND HEAVY RAIN IS THERE TOO.
SHOWERS AND STORMS HAVE BEEN RIDING EAST ALONG THE INTERNATIONAL
BORDER THIS MORNING. IT APPEARS THIS TREND WILL CONTINUE THROUGH
AT LEAST EARLY THIS AFTERNOON BEFORE PERHAPS SUBSIDING A BIT
DURING THE MID AFTERNOON. I AM LEANING ON THE LATEST HRRR AND 00Z
NCEP WRF SIMULATED REFLECTIVITY...AS WELL AS THE 12Z NAM...FOR MY
FORECAST THROUGH TONIGHT. THESE MODELS CAPTURE THE LULL IN
ACTIVITY DURING THE MID AFTERNOON...THEN SHOWING A LINE OF
THUNDERSTORMS FORMING EITHER LATE THIS AFTERNOON OR EARLY THIS
EVENING NEAR THE WESTERN FORECAST AREA. I AM LIKING THIS IDEA. I
AT LEAST LEFT LOW PCPN CHANCES ACROSS THE ENTIRE FORECAST THROUGH
THIS AFTERNOON DUE TO THE LACK OF INHIBITION...SO I CANNOT RULE
OUT A SHOWER/STORM HERE AND THERE. THE LINE OF STRONG/SEVERE
STORMS LATE THIS AFTERNOON AND EARLY THIS EVENING SHOULD THEN MOVE
EAST AND SOUTH THROUGH THIS EVENING. I ADDED SEVERE WORDING TO THE
FORECAST ACROSS THE NORTHERN AND WESTERN FORECAST AREA. I MIGHT
HAVE TO ADD MORE WORDING WITH A LATER UPDATE...LIKE THE THREAT OF
DAMAGING WINDS...HEAVY RAIN...AND LARGE HAIL.
I ALSO INCREASED WINDS ACROSS THE SOUTHERN HALF OF THE FORECAST
AREA THROUGH THIS AFTERNOON. THE LATEST NAM12 AND SOUNDINGS
INDICATE PRETTY GOOD MIXING...SO I WOULD NOT BE SURPRISED IF SOME
AREAS SEE GUSTS IN THE 25 TO 30 MPH RANGE. I KEPT THE TEMPERATURE
FORECAST IN THE UPPER 80S AND LOW 90S...DESPITE SOME GUIDANCE
WANTING TO LOWER THE TEMPERATURES...BECAUSE THE SUNSHINE AND
MIXING SHOULD WARM UP THE SOUTHERN FORECAST AREA REALLY WELL. I
WOULD NOT BE SURPRISED IF I HAVE TO INCREASE THE TEMPERATURES EVEN
MORE DUE TO HOW QUICKLY THE SOUTH IS ALREADY WARMING THIS MORNING.
DUE TO THE HIGH HUMIDITY...THE HEAT INDICES WILL LIKELY REACH THE
95 TO 100 DEGREE RANGE ACROSS PARTS OF THE SOUTHERN HALF OF THE
FORECAST AREA THIS AFTERNOON. IT DOES NOT APPEAR THAT WE NEED A
HEAT ADVISORY AT THIS TIME...BUT SOME AREAS COULD BRIEFLY APPROACH
CRITERIA...WHICH IS A HEAT INDEX OF 100 DEGREES.
&&
.PREV DISCUSSION... /ISSUED 642 AM CDT THU JUL 18 2013/
AVIATION...12Z TAFS
A WARM FRONT DRAPED ACROSS NORTHERN MINNESOTA WAS THE FOCUS FOR
SHOWERS AND STORMS OVERNIGHT...AND WILL CONTINUE TO BE THROUGH
MUCH OF THE MORNING. AREAS OF FOG HAVE FORMED...BUT WAS ALREADY
LIFTING AT KHIB WHICH WAS 1/4SM IN FG EARLIER. FOG WAS OCCURRING
AROUND LAKE SUPERIOR...AND COULD CREEP OVER THE HILL IN DULUTH AND
AFFECT THE KDLH TAF FOR A PERIOD AS WINDS WILL BE ONSHORE FOR A
TIME TODAY. WE EXPECT MVFR OR BRIEF IFR CONDITIONS IN FOG EARLY THIS
MORNING...THEN THROUGH THE DAY IN ANY SHOWERS/STORMS.
A STRONGER SHORTWAVE WILL MOVE IN FROM THE NORTHWEST LATER TODAY
INTO TONIGHT...AND PUSH A COLD FRONT THROUGH THE REGION.
ADDITIONAL THUNDERSTORMS WILL FORM AS THIS FEATURE MOVES
THROUGH...AND SOME OF THE STORMS COULD BE SEVERE PRODUCING LARGE
HAIL AND DAMAGING WINDS. SOME ADDITIONAL STORMS WILL BE POSSIBLE
BEHIND THE FRONT AS WELL...MAINLY AFFECTING FAR NORTHERN AREAS.
GUSTY SOUTH/SOUTHWEST WINDS CAN BE EXPECTED TODAY...ESPECIALLY BY
LATE MORNING/EARLY AFTERNOON ONCE MIXING DEEPENS.
PREV DISCUSSION... /ISSUED 356 AM CDT THU JUL 18 2013/
.STRONG/SEVERE STORMS EXPECTED LATER TODAY/TONIGHT...
SHORT TERM...STATIONARY FRONTAL BDRY ACROSS CWA ASSISTING WITH
CONTINUED GENERATION OF CONVECTION ACROSS NRN/CTRL TIER OF MN ZONES
EARLY THIS MORNING. INITIAL AREA OF STORMS MOVING EASTWARD OVER
WRN LAKE SUPERIOR WITH NEW DEVELOPMENT OCCURRING ACROSS NWRN KOOCH
COUNTY. FARTHER SOUTH CONVECTION NOT AS WIDESPREAD ALTHOUGH LATEST
INDICATIONS ON SPC MESOANALYSIS SHOWS DEVELOPING 85H FRONTOGENESIS
FROM ITASCA COUNTY TO SOUTH SHORE OF LAKE SUPERIOR. MAY SEE
INCREASE ALONG THIS CORRIDOR NEXT FEW HRS.
TODAY/TONIGHT...FRONTAL BDRY WILL ADVECT NORTH IN RESPONSE TO APPROACHING
COLD FRONT AND ASSOCIATED DEEPENING MID LVL SHORTWAVE. EXPECT WARM
FRONTOGENESIS TO ENHANCE AREA OF CONVECTION ACROSS THE CWA AS IT
LIFTS NORTH THIS MORNING. WELL ESTABLISHED WARM SECTOR SHOULD
COVER A LARGE PART OF CWA BY MIDDAY. THIS WILL YIELD MAX TEMPS
ABOVE GUIDANCE AGAIN WITH BRISK SWRLY FLOW IN BDRY LYR WITH
CONSIDERABLE GUSTS DURING THE AFTN AHEAD OF FRONT. GENERAL
CONSENSUS AMONG HI RES MDLS...ALBEIT SOME DIFFERENCES IN
TIMING...IS THAT AN INCREASINGLY INTENSE LINE OF CONVECTION WILL
ORGANIZE JUST WEST OF THE CWA MID/LATE AFTERNOON AND PLOW
SOUTHEASTWARD UNDER AMPLIFYING MID LVL TROF. SBCAPES AHEAD OF
FRONT WILL RANGE FROM 4000 TO 4500 J/KG AND EFFECTIVE SHEAR SHOULD
INCREASE TO 40/45KTS. THESE VALUES WILL GENERATE A LINE OF
STRONG/SVR STORMS WITH INCREASING POTENTIAL OF CONSIDERABLE WIND
DAMAGE AND HAIL. MAY SEE LINE EVOLVE INTO AN MCS AS IT RIDES SE
WITH SOME INDICATION IN DIFFLUENT THICKNESS FIELD THAT CORE OF
CONVECTION MAY TREND MORE SOUTH TOWARDS LWR ST CROIX VALLEY BY 12Z.
TOMORROW...INITIAL COLD FRONT WILL MOVE SOUTH OF CWA BY MID
MORNING. A SECONDARY FRONT...INDICATED IN LOW LVL THETAE
FIELDS...WILL MOVE ACROSS MN ZONES IN THE LATE MORNING/AFTN HRS.
GUSTY WINDS AND LOWERING HUMIDITY WILL RESULT HAVE KEPT INHERITED
DRY FCST FOR AFTN WITH IDEA THE SUFFICIENT MOISTURE WILL NOT BE
AVAILABLE BY AFTERNOON. SUSPECT THAT A FEW RW MAY TRY TO POP IN
AFTN INSTABILITY UNDER STEEPENING LAPSE RATES.
FRIDAY NIGHT THROUGH WEDNESDAY.
THIS FRIDAY NIGHT THROUGH WEDNESDAY TIME WILL FEATURE CHANCES FOR
SHOWERS/STORMS FOR MOST PERIODS...WITH A FAST WEST-NORTHWEST FLOW
ALOFT BRINGING PERIODIC SHORTWAVES THROUGH AND WITH A BAROCLINIC
ZONE REMAINING OVER/NEAR THE AREA.
COLD AIR ADVECTION WILL CONTINUE FRIDAY NIGHT AS HIGH PRESSURE
BUILDS INTO THE REGION. WE WENT DRY FRIDAY NIGHT...ALTHOUGH A FEW
MODELS SUGGEST SOME SHOWERS MAY LINGER INTO THE EVENING.
SEVERAL MODELS SHOW SOME LIGHT PRECIP POSSIBLE OVER OUR SOUTHERN CWA
ON SATURDAY DUE TO A WEAK WAVE AND TIGHT THERMAL GRADIENT. WE HAVE
SLIGHT CHANCE POPS ACROSS OUR SOUTHERN CWA BOTH SATURDAY AND
SATURDAY NIGHT.
THE SURFACE HIGH IS EXPECTED TO SLIDE EAST OF THE REGION SATURDAY
NIGHT INTO SUNDAY WITH A RETURN FLOW AND FAST WEST-NORTHWEST FLOW
ALOFT BRINGING FAST MOVING SHORTWAVES OVER/NEAR THE CWA. WE WILL
HAVE SMALL CHANCES FOR SHOWERS/STORMS OVER MUCH OF THE NORTHLAND
SUNDAY/SUNDAY NIGHT...ALTHOUGH THE PRECIP DOES NOT LOOK TO BE
PARTICULARLY WIDESPREAD OR HEAVY.
WE HAVE HIGHER POPS FOR MONDAY-TUESDAY AS A SURFACE LOW/FRONT
AFFECTS THE NORTHLAND.
WE EXPECT HIGHS SATURDAY IN THE UPPER SIXTIES TO MID
SEVENTIES...WITH THEM WARMING TO THE MID SEVENTIES TO LOWER EIGHTIES
BY MONDAY LASTING INTO WEDNESDAY.
&&
.POINT TEMPS/POPS...
DLH 90 66 78 52 / 40 60 20 10
INL 80 60 75 46 / 80 60 20 10
BRD 92 69 81 55 / 40 60 20 10
HYR 92 71 83 53 / 50 60 30 10
ASX 89 67 78 52 / 50 60 30 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...GROCHOCINSKI
LONG TERM....STEWART
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
1223 PM CDT THU JUL 18 2013
.MESOSCALE UPDATE...SHOWERS AND THUNDERSTORMS INCREASING IN COVERAGE
ACROSS NORTHERN PART OF AREA IN ASSOCIATION WITH WAVE WHICH CONTINUES
TO MOVE WEST INTO FORECAST AREA. HAVE UPDATED (AGAIN) TO INCREASE
POPS TO 50-60 RANGE AND WORD SCATTERED/NUMEROUS ACROSS NORTHERN
THIRD OF FORECAST AREA. STILL CONCERNED ABOUT POTENTIAL FOR STRONG
AND A FEW SEVERE STORMS WEST OF CURRENT ACTIVITY GIVEN SPC
MESOANALYSIS ALREADY SHOWING SBLI OF -9...20-25 OF EFFECTIVE
SHEAR...AND THINNING CLOUDS RESULTING IN INCREASED DIURNAL HEATING
AHEAD OF ACTIVITY. ALSO LOCAL WET MICORBURST COMPOSITE PARAMETER
SHOWN BY LATEST RUC TO BE MAXING OUT OVER ARKLAMISS REGION LATER THIS
AFTERNOON. HENCE EXPECT ACTIVITY TO CONTINUE TO EXPAND IN COVERAGE
AND GRADUALLY INCREASE IN INTENSITY AS IT MOVES/PROPAGATES W/SW NEXT
SEVERAL HOURS.
FARTHER SOUTH...DIVERGENT LOW LEVEL FLOW IN WAKE OF MORNING MCS
RESULTING IN DISSIPATION OF SHOWERS. HOWEVER...SITUATION MAY EVOLVE
INTO MORE FAVORABLE SETUP DEPENDING ON AIRMASS RECOVERY THROUGH THE
AFTERNOON. WILL KEEP CHC POPS/WORDING FOR NOW.
&&
.AVIATION...
SHOWER AND THUNDERSTORM COMPLEX THAT MOVED THROUGH ERN
SITES EARLIER THIS MRNG HAS NOW PUSHED IN SE/CNTRL AND SC AREAS OF
MS IMPACTING KHBG AND KJAN/KHKS. KHBG IS LIFR AS OF 14Z WITH LOW
VISIBILITY DUE TO TSRA. TSRA WILL WEAKEN OVER NEXT HOUR AND RA WILL
END ALL TOGETHER THROUGH 1530Z WITH FLIGHT CATS IMPROVING TO VFR.
EXPECT A RETURN OF SCATTERED SHRA/TSRA NEAR KHBG THIS AFTN AS ATMOS
BECOMES UNSTABLE ONCE AGAIN. VFR -RA NEAR KJAN/KHKS AS OF 14Z WILL
LIGHTEN THROUGH 15-16Z WITH CLOUD DECKS BECMG SCT THROUGH AFTN WITH
MORE TSRA POSSIBLE BY 18-19Z. W MS/NE LA NOT TOUCHED BY COMPLEX WILL
BE MORE FAVORED REGION FOR GREATER COVERAGE OF AFTN TSRA. SOME TSRA
COULD BE STRONG TO SEVERE. ALL SHRA/TSRA ACTIVITY EXPECTED TO
DIMINISH THROUGH MID EVENING HOURS. WILL MONITOR FOG POTENTIAL
OVRNGT GIVEN TODAYS RAINFALL AND HAVE ALREADY PLACED MVFR BASED ON
VIS IN ERN LOCATIONS. /ALLEN/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 90 69 92 70 / 40 24 32 26
MERIDIAN 90 69 92 68 / 40 24 31 26
VICKSBURG 90 68 92 68 / 40 24 31 26
HATTIESBURG 90 70 92 70 / 40 24 40 26
NATCHEZ 90 69 92 69 / 40 24 39 26
GREENVILLE 94 71 93 72 / 44 24 30 26
GREENWOOD 91 70 93 70 / 55 24 30 26
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
AEG/JA
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
827 AM CDT THU JUL 18 2013
.UPDATE...
UPDATED GRIDS TO RAISE POPS IN SOUTH CENTRAL/SE MS AND LOWER THEM
ACROSS THE CENTRAL AND NORTH FOR THE AM.
&&
.SHORT TERM...
MCS CONTINUES TO FORWARD PROPAGATE WSW ACROSS SOUTH CENTRAL AND SE MS
TOWARD THE FLORIDA PARISHES OF LA. OVERALL ACTIVITY HAS SHOWN A
MARKED DECREASE IN INTENSITY OVER THE LAST 6O MINUTES...AND TRENDS AND
HRRR WOULD INDICATE THIS IS SHOULD CONTINUE. HAVE ADJUSTED THE
MORNING POPS TO SHOW CATEGORICAL IN SC/SE WHERE RAIN IS CURRENTLY
ONGOING...AND REDUCED FARTHER TO THE ALONG AND N OF I-20 WHERE
PRECIPITATION AREA HAS SUBSTANTIALLY DIMINISHED.
BIG QUESTION FOR REST OF DAY IS WHAT HAPPENS IN WAKE OF MORNING
ACTIVITY. SATELLITE SHOWS WHAT LOOKS TO BE ANOTHER WAVE CURRENTLY
MOVING ACROSS N AL AND MID TN. A FEW SHRA/TSRA ARE ASSOCIATED WITH THIS
FEATURE. DEPENDING ON HOW MUCH CLOUDS WITH CURRENT MCS THIN...THIS WAVE
COULD REFIRE ACTIVITY ACROSS NORTHERN AREAS THIS AFTERNOON. LZK
SOUNDING WOULD IMPLY ANY ACTIVITY THAT WOULD DEVELOP IN THIS AREA
COULD BE QUITE ROBUST WITH MICROBURST POTENTIAL. FARTHER S ADDITIONAL
DEVELOPMENT COULD TAKE PLACE ACROSS SW MS AND EC LA ALONG RESIDUAL
OUTFLOW. HRRR SHOWS THIS OCCURRING...BUT AGAIN LOW CONFIDENCE
SOLUTION AS IT DEPENDS ON HOW DEBRIS AND OUTFLOW BEHAVE NEXT FEW
HOURS. FOR NOW HAVE KEPT POPS FOR AFTERNOON PRETTY MUCH AS PREVIOUS
FORECAST HAD IT...AND WILL TRY TO ADJUST TOWARD MIDDAY AS TRENDS GET
MORE CLEAR. TEMPS COULD ALSO NEED TWEAKED AT THAT TIME...BUT CURRENT
TREND OF GOING BLO GUIDANCE SEEMS REASONABLE GIVEN OUTFLOW AND DEBRIS
ACROSS AREA ATTM.
&&
.PREV DISCUSSION... /ISSUED 353 AM CDT THU JUL 18 2013/
..STRONG TO SEVERE STORMS POSSIBLE ACROSS THE ENTIRE REGION TODAY...
DISCUSSION...
SHORT TERM (TODAY THROUGH FRIDAY NIGHT)...THE UPPER TROPOSPHERIC
(TUTT) LOW WHICH HAS BEEN HELPING INSTIGATE CONVECTION TO OUR EAST
THE PAST FEW DAYS IS NOW IN A POSITION TO INCREASE OUR SHOWER AND
THUNDERSTORM CHANCES. IN FACT...JUXTAPOSED LIFT AND INSTABILITY
ASSOCIATED WITH THE LOW HAS BEEN GREAT ENOUGH TO ADVECT SHOWERS AND
THUNDERSTORMS INTO EAST-CENTRAL AND NORTHEASTERN PORTIONS OF
MISSISSIPPI OVERNIGHT. SOME OF THIS ACTIVITY HAS BEEN QUITE
VIGOROUS...PRODUCING GUSTY WINDS AT LEAST OVER 40 MPH OVER LARGE
PORTIONS OF THE GOLDEN TRIANGLE. HIGH RESOLUTION MODELS GENERALLY
SUGGEST ACTIVITY BUILDING DOWN THROUGH THE HEART OF THE REGION
THROUGH MIDDAY...AND THEN BECOMING CONCENTRATED IN WESTERN
(ESPECIALLY SOUTHWESTERN) ZONES BY THIS AFTERNOON. RELATIVELY COLD
TEMPERATURES ALOFT WILL CREATE RATHER STEEP LAPSE RATES (26 TO 28
VERT TOTALS) WITH ENOUGH DEEP LAYER SHEAR TO OCCASIONALLY ORGANIZE
GUSTY THUNDERSTORM LINE SEGMENTS. EARLY ONSET OF CONVECTION
(ESPECIALLY IN CENTRAL AND EASTERN ZONES) WILL IN MANY CASES KEEP
INSTABILITY FROM MAXIMIZING...BUT ALL THE INGREDIENTS FOR AT LEAST
ISOLATED SEVERE SUMMER STORMS STILL SEEM TO BE THERE. THIS RISK WILL
BE MENTIONED IN THE HWO (WITH THE FOCUS ON DAMAGING WIND GUSTS). GFS-
BASED MAV GUIDANCE REALLY STRUGGLING TO CATCH UP TO THE SITUATION
THIS MORNING AND ITS POPS WERE INCREASED RATHER
SIGNIFICANTLY...ALTHOUGH NOT BY A HUGE AMOUNT IN PORTIONS OF EAST-
CENTRAL MS WHERE MAIN CONVECTIVE BANDS MAY PASS THROUGH BEFORE THE
TODAY PERIOD STARTS. MAV TEMPS OF COURSE DEEMED AT LEAST 2 TO 4
DEGREES TOO HIGH IN MOST LOCALES DUE TO THE EXPECTED WETTER OUTCOME
TO THE DAY.
QUITE A FEW MODELS BLOW UP SO MUCH CONVECTION ACROSS OUR REGION
THROUGH EARLY TO MID AFTERNOON THAT IT IS CONCEIVABLE THERE MAY NOT
BE MUCH AROUND BY LATE AFTERNOON TO EARLY EVENING. THIS IS CONTRAST
TO USUAL PEAK CONVECTION TIME AROUND HERE IN THE SUMMER.
HOWEVER...VICINITY OF THE UPPER LOW CENTER TO OUR SOUTH WILL
INCREASE OUR CHANCES OF AT LEAST ISOLATED LATE NIGHT CONVECTION
FORMING ACROSS OUR REGION...ALTHOUGH INGREDIENTS FOR TRIGGERING DO
NOT APPEAR NEARLY AS ABUNDANT AS IS THE CASE RIGHT NOW. THE NEXT
SHIFT WILL HAVE TO MONITOR POTENTIAL FOR ANY POTENT LATE NIGHT
STORMS...BUT AS OF RIGHT NOW THE RISK OF ANY SEVERE ACTIVITY DOES
NOT LOOK VERY HIGH.
THE PICTURE FOR FRIDAY GETS A BIT MURKIER. SEEMS AS IF CONVECTION
TODAY IN THE MODELS DISRUPTS LOW LEVEL WIND FIELDS SO MUCH THAT THEY
HAVE A HARD TIME REORGANIZING AGAIN BY FRIDAY. THIS RESULTS IN A
LACK OF TRIGGERING MECHANISMS IN OUR REGION AND THUS A SURPRISING
LACK OF CONVECTION GIVEN STILL FAVORABLE UPPER LEVEL SCENARIO. THERE
IS A POSSIBILITY THESE DRY-LOOKING MODELS MAY BE ON TO SOMETHING BUT
I AM GUESSING THEY ARE TOO DRY AND HAVE BOOSTED POPS TO A 30 TO 40
PERCENT RANGE. THE NEXT SHIFT SHOULD LIKELY HAVE A BETTER HANDLE ON
THE SITUATION FOR TOMORROW. GIVEN UNCERTAINTIES I MAY DOWNPLAY
SEVERE POTENTIAL IN THE HWO A LITTLE...ALTHOUGH STILL MENTIONING
SOME RISK. FOLLOWED TREND OF ENSEMBLE GFS MOS AND CUT MEXMOS HIGHS
FOR FRIDAY BY ONE OR TWO DEGREES. /BB/
LONG TERM (SATURDAY THROUGH NEXT THURSDAY)...THE WEATHER PATTERN
WILL REMAIN SOMEWHAT ACTIVE DURING THE EXTENDED PART OF THE FORECAST
AS MULTIPLE UPPER DISTURBANCES SWING ACROSS THE REGION DURING THE
PERIOD.
ON SATURDAY A TUTT LOW WILL BE SITUATED OVER THE LOWER MS VALLEY.
WITH A RATHER MOIST AIRMASS IN PLACE ACROSS THE REGION...THIS FEATURE
WILL LIKELY AID IN THE DEVELOPMENT OF SCATTERED CONVECTION DURING THE
DAY. MOVING INTO SUNDAY AND MONDAY THE LOW WILL OPEN UP AND BECOME
ABSORBED BY THE LARGER-SCALE UPPER TROUGH BROADENING OVER THE EASTERN
CONUS. THIS WILL PUT THE ARKLAMISS IN WNW/NORTHWESTERLY FLOW ALOFT
THROUGH THE MIDDLE OF NEXT WEEK. A SERIES OF SHORTWAVE IMPULSES WILL
TRAVERSE THIS UPPER FLOW PATTERN BRINGING MULTIPLE OPPORTUNITIES FOR
RAIN FROM THE WEEKEND INTO THE FIRST HALF OF NEXT WEEK. CHANCE POPS
WERE MAINTAINED FOR SEVERAL PERIODS IN THE EXTENDED.
THE 00Z MODEL SUITE SUGGESTS THE UPPER TROUGH MAY NOT DEEPEN QUITE AS
MUCH OVER OUR REGION EARLY NEXT WEEK AS INDICATED IN PREVIOUS RUNS
DUE TO A STRENGTHENING UPPER RIDGE EXTENDING FROM THE SOUTHERN
PLAINS INTO THE NORTHERN GULF. THIS RIDGE WOULD BECOME THE BIGGER
PLAYER IN OUR FORECAST MID TO LATE NEXT WEEK...BRINGING AN END TO
THE STRETCH OF DAYS WITH ABOVE-CLIMO POPS. THIS WOULD ALSO CRANK UP
THE HEAT...WITH HIGH TEMPERATURES IN THE MID 90S BECOMING MORE
PREVALENT.
WITH REGARDS TO FORECAST SPECIFICS...POPS WERE GENERALLY A COMPROMISE
BETWEEN MAV GUIDANCE AND ENSEMBLE MEANS. UNDERCUT MAV/MEX HIGHS
THROUGH MUCH OF THE PERIOD DUE TO THE INCREASED PRESENCE OF CLOUDS
AND PRECIPITATION. /DL/
&&
.AVIATION...
SCATTERED SHOWERS AND THUNDERSTORMS WILL GRADUALLY
SPREAD WEST THROUGH THE AERODROME THROUGHOUT THE DAY...WITH ACTIVITY
AFFECTING GTR/CBM/NMM/MEI/PIB/HBG MAINLY THIS MORNING. MVFR TO
OCCASIONALLY IFR CONDITIONS AND GUSTY WINDS WILL BE FOUND IN THE
MIDST OF THE THUNDERSTORMS...BUT OUTSIDE OF MOST CELLS CONDITIONS
SHOULD BE MAINLY VFR. ACTIVITY SHOULD BE CONCENTRATED AROUND
GWO/JAN/HKS BY LATE MORNING TO MIDDAY...AND THEN AROUND HEZ/TVR/GLH
BY AFTERNOON. /BB/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 91 69 92 70 / 57 24 32 26
MERIDIAN 91 69 92 68 / 54 24 31 26
VICKSBURG 91 68 92 68 / 58 24 31 26
HATTIESBURG 91 70 92 70 / 94 24 40 26
NATCHEZ 91 69 92 69 / 64 24 39 26
GREENVILLE 95 71 93 72 / 41 24 30 26
GREENWOOD 92 70 93 70 / 35 24 30 26
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
AEG
AREA FORECAST DISCUSSION
NWS GLASGOW MT
247 PM MDT THU JUL 18 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SATURDAY...
A VERY WELL MIXED BOUNDARY LAYER THIS AFTERNOON AND EVENING HAS
BEEN LEADING TO GUSTY NORTHWEST WINDS ACROSS THE CWA. NOTICED THAT
SOME GUSTS HAVE BEEN APPROACHING 40 MPH AT TIMES. THEREFORE THE
GOING LAKE WIND ADVISORY LOOKS GOOD. WINDS ARE EXPECTED TO SUBSIDE
THIS EVENING...ESPECIALLY AROUND OR AFTER SUNSET. AT THAT TIME THE
NEXT SHIFT CAN HAVE A LOOK AT DETERMINING WHETHER OR NOT THE
HEADLINES CAN BE DROPPED A LITTLE EARLY. FOR NOW...WILL LEAVE IT
TO EXPIRE AT MIDNIGHT. DEEP VERTICAL MIXING HAS ALSO LED TO
TEMPERATURES SOARING INTO THE MIDDLE AND UPPER 80S ACROSS THE
FORECAST AREA WITH A FEW LOCATIONS TOPPING 90. SOME LOCATIONS WERE
EVEN A TAD WARMER THAN EXPECTED. CUMULUS FIELD EVIDENT ON THE
VISIBLE SATELLITE IMAGERY PUSHING INTO THE NORTHERN ZONES FROM
SOUTHERN SASKATCHEWAN. DO EXPECT THAT WHILE THE UPPER SHORT WAVE
MAY CLIP THE NORTHEASTERN ZONES THAT MUCH OF THE UPPER LEVEL
ENERGY WILL REMAIN NORTH AND EAST OF THE CWA. FELT THAT IT WAS
OKAY TO LEAVE IN SLIGHT CHANCE POPS FOR THE AFTERNOON AND EVENING
HOWEVER. LATEST HRRR MODEL DOES INDICATE POTENTIAL FOR AN ISOLATED
SHOWER OR THUNDERSTORM ACROSS PERHAPS DANIELS OR SHERIDAN COUNTY
RIGHT AROUND OR JUST AFTER 00Z.
FRIDAY AND SATURDAY...18/12Z MODEL GUIDANCE CONTINUES TO LEAVE
NORTHEAST MONTANA UNDER A REGIME OF NORTHWEST FLOW ALOFT.
SHORTWAVE ENERGY PROPAGATING THROUGH THE FLOW WILL BRING ABOUT
PERIODIC OPPORTUNITIES FOR SHOWERS AND THUNDERSTORMS... AS IT
RIDES OVER THE TOP OF A BACKDOOR COLD FRONT THAT IS EXPECTED TO
STALL OUT ACROSS THE CWA. MOISTURE IS EXPECTED TO BE QUITE
LIMITED. THEREFORE KEPT SLIGHT CHANCE TO LOW END CHANCE POPS GOING
FOR NOW...ESPECIALLY IN THE NORTHERN AND EASTERN PORTIONS OF THE
CWA. TEMPERATURES LOOK TO BE FAIRLY SEASONABLE WITH 850MB
TEMPERATURES EXHIBITING A SHARP GRADIENT WITH WARMER TEMPERATURES
ACROSS THE SOUTHWEST AND COOLER IN THE NORTHEAST. WITH THE
FORECAST REGION REMAINING ON THE NORTHEAST PERIPHERY OF THE UPPER
RIDGE ACROSS THE SOUTHWESTERN U.S. HOWEVER...DO NOT EXPECT ANY
MAJOR TRENDS IN TEMPERATURES THROUGH EARLY IN THE WEEKEND. MINOR
FLUCTUATIONS DAY TO DAY ARE POSSIBLE...BUT PERSISTENCE MAY BE A
NICE BASELINE TO START FROM FOR THE FORECAST FOR AT LEAST THE NEXT
COUPLE OF DAYS. WITH ANTICIPATED 850MB TEMPERATURE PATTERN...FULL
MIXING WOULD PROBABLY ENABLE HIGHS AROUND 90 IN PETROLEUM
COUNTY...RANGING TO CLOSER TO 90 IN SHERIDAN COUNTY FURTHER
NORTHEAST. LOW TEMPERATURES EACH MORNING MAY RANGE IN THE UPPER
50S TO LOW 60S. MALIAWCO
.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY...
MAIN CHANGE WAS ADD MENTION OF THUNDERSTORMS FOR LATE MONDAY. ECMWF
REMAINS CONSISTENT WITH A DECENT VORT MAX MOVING EAST INTO MONTANA
AND DECENT INSTABILITY IN PLACE. CURRENT HWO DOES NOT MENTION
SEVERE THUNDERSTORM POSSIBILITY BUT LATER SHIFTS MAY HAVE TO ADD
THIS MENTION IF MODELS START TO LEAN IN THIS DIRECTION. REST OF
FORECAST MAINLY UNCHANGED. TFJ
PREVIOUS DISCUSSION...
BOTH THE ECMWF AND THE GFS MAINTAIN A WNW FLOW ALOFT IN TONIGHT/S
00Z MODEL RUNS THROUGH THE PERIOD. HOWEVER...THERE HAS BEEN RUN TO
RUN DIFFERENCES AND DIFFERENCES IN TIMING SHORTWAVES WITHIN THE
FLOW ALOFT. GENERALLY...MONTANA WILL BE ON PERIPHERY OF WESTERN
U.S. UPPER RIDGE.
AT THIS POINT...BOTH GFS AND ECMWF POINT TOWARDS SUNDAY AND MONDAY
BEING WARM AND MAINLY DRY WITH A SHORTWAVE RIDGE. MONDAY NIGHT AND
TUESDAY...ECMWF IS STRONGER AND SOMEWHAT FASTER WITH A COLD FRONT.
EITHER WAY...IT LOOKS LIKE LIMITED MOISTURE SO WILL MAINTAIN DRY
FORECAST FOR NOW AND KEEP TEMPERATURES CLOSE TO INHERITED FORECAST.
WEDNESDAY AND THURSDAY...WNW FLOW ALOFT CONTINUES WITH MODELS
TIMING SYSTEMS DIFFERENTLY. THEY GENERALLY KEEP THE AREA DRY WITH
TEMPERATURES AT OR SLIGHTLY ABOVE NORMAL. FORRESTER
&&
.AVIATION...
VFR. NORTHWEST WINDS WILL SIGNIFICANTLY DIMINISH THIS EVENING
ABOUT 03Z TO LIGHT SPEEDS. NW WINDS WILL PICK UP AGAIN FRIDAY
AFTERNOON BUT NOT NEARLY AS STRONG AS TODAY. A BACKDOOR COLD FRONT
WILL KEEP MOST VFR CLOUDS TO THE NORTH AND EAST OF THE TERMINALS
LATER FRIDAY. TFJ
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY UNTIL MIDNIGHT MDT TONIGHT FOR FORT PECK LAKE
FOR CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN
VALLEY...GARFIELD...MCCONE...PETROLEUM.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
339 PM EDT THU JUL 18 2013
.SYNOPSIS...
AN ACTIVE WEATHER PATTERN WILL CONTINUE ACROSS THE NORTH COUNTRY
WITH DAILY CHANCES FOR SCATTERED SHOWERS AND THUNDERSTORMS...
ALONG WITH HOT AND HUMID CONDITIONS THROUGH THE END OF THE WEEK.
SOME STORMS COULD BE STRONG TO SEVERE THROUGH THE PERIOD. A COLD
FRONT WILL MOVE THROUGH ON SATURDAY BRINGING MUCH DRIER AND
COOLER AIR FOR SUNDAY AND MONDAY.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
AS OF 107 PM EDT THURSDAY...VISIBLE SATELLITE SHOWS DEVELOPING
CUMULUS/TOWERING CUMULUS CLOUDS ACROSS THE HIGHER TERRAIN...WITH
SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING ACROSS EASTERN
ONTARIO AND IN CENTRAL AND SOUTHERN NEW YORK. AIRMASS ALREADY
QUITE UNSTABLE WITH SBCAPES OF 2500-3500 J/KG PER LATEST RAP AND
LAPS ANALYSIS. BASED ON SATELLITE TRENDS AND THE LACK OF
CONVECTIVE INHIBITION...EXPECT AN INCREASE IN COVERAGE OF SHOWERS
AND THUNDERSTORMS ACROSS NORTHERN NEW YORK THROUGH THE NEXT COUPLE
OF HOURS WITH THIS ACTIVITY DEVELOPING/SPREADING INTO VERMONT BY
LATE AFTERNOON/EVENING. NO CHANGES TO POPS/WEATHER AS THESE ARE
REFLECTED IN THE CURRENT FORECAST...AND STILL BELIEVE ENHANCED
WORDING FOR GUSTY WINDS AND HEAVY RAINFALL IS JUSTIFIED GIVEN
DEGREE OF INSTABILITY AND FAVORABLE DEEP- LAYER SHEAR PROFILES.
PLEASE SEE OUR RECENTLY ISSUED SPECIAL WEATHER STATEMENT TO RAISE
AWARENESS OF POTENTIALLY STRONG THUNDERSTORMS THIS AFTERNOON AND
EVENING.
ENDED UP RAISING TEMPERATURES UP A DEGREE BASED ON CURRENT TRENDS.
STILL EXPECT HIGHS TODAY IN THE UPPER 80S TO LOWER 90S WITH HEAT
INDICES IN THE MID/UPPER 90S.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH SATURDAY NIGHT/...
AS OF 533 AM EDT THURSDAY...LINGERING CONVECTION THIS EVENING
WITH BR/FG DEVELOPING OVERNIGHT...ESP AT LOCATIONS THAT RECEIVE
RAINFALL. TOWARDS EARLY MORNING HOURS ON FRIDAY...NAM AND GFS
SHOW WARM FRONT LIFTING NWD...BEGINNING THREAT FOR SHOWERS AND
TSTMS EARLY. LLJ AROUND 30-45KTS WILL ACCOMPANY THE
FRONT...PROVIDING PLENTY OF SHEAR TO HELP ORGANIZE CONVECTION.
CAPE VALUES WILL BE EVEN HIGHER WITH OVER 2500 J/KG PSBL AND
SHOWALTER INDEX AROUND -3. CLEARLY DEFINE THETA E RIDGING
SUPPORTS INDICATIONS OF LARGE INSTABILITY OVER THE AREA. WARM
HUMID CONDITIONS CONTINUE ON FRIDAY...BUT FRONT WILL ALSO HAVE
SUPPORT FROM VORTICITY WHICH WILL CONTINUE TO MOVE OVER THE
REGION INTO THE OVERNIGHT. THEREFORE EXPECT BEST CHCS FOR
CONVECTION TO OCCUR ON FRIDAY INTO FRIDAY NIGHT AS MID LEVEL HT
FALLS SEE A MORE DRAMATIC CHANGE FRIDAY NIGHT WHILE UPPER LEVEL
TROUGH GAINS MOMENTUM EWD...GRAZING THE CENTRAL GREAT LAKES AND
PUSHING THE LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT AT THE
SFC FORWARD. GOING INTO SATURDAY...COLD FRONT WILL BE FOCUS OF
SHOWERS AND TSTMS...WITH CAPE OVER 1000 J/KG AND LI AROUND -3C.
UPPER LEVEL JET ACCOMPANYING THE FRONT WILL POSITION THE RR QUAD
OVER THE SLV FRIDAY NIGHT AND MOVE EWD THROUGHOUT THE DAY
SATURDAY. THE COLD FRONT DOESN/T LOOK TO EXIT ERN VT UNTIL LATE
SATURDAY INTO SATURDAY EVENING.
TEMPS WILL BE HOT WITH 925MB REACHING MID20S ON FRIDAY...
RESULTING IN SFC MAX TEMPS IN THE U80S-M90S...ESP IN SW DOWNSLOPE
AREAS LIKE PBG. HEAT INDEX VALUES WILL ONCE AGAIN APPROACH 100
DEGREES IN A FEW LOCATIONS MAINLY IN THE CPV AND CT VALLEY. WITH
MORE CLD COVER ON SATURDAY...EXPECT MAX TEMPS TO BE IN THE
M-U80S. OVERNIGHT MIN TEMPS WILL BE WARM...IN THE 60S- L70S.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 330 PM EDT THURSDAY...LARGE SCALE PATTERN CHANGE WL BRING
MUCH COOLER AND DRIER AIR INTO THE NORTH COUNTRY FOR SUNDAY INTO
MONDAY...BEFORE MORE UNCERTAINTY ASSOCIATED WITH NEXT SYSTEM
DEVELOPS BY TUES/WEDS OF NEXT WK. OVERALLL...GFS/ECMWF AND
ENSEMBLE DATA SHOW DEVELOPING TROF ACRS THE NE CONUS WITH SFC HIGH
PRES OVERHEAD ON SUN/MON...RESULTING IN DRY CONDITIONS WITH NEAR
NORMAL TEMPS. THE COMBINATION OF NW FLW...CAA...AND 85H TEMPS BTWN
6-8C WL RESULT IN HIGHS ONLY IN THE 60S MTNS TO 70S VALLEYS ON
SUN/MONDAY. BY TUES/WEDS...FAST WESTERLY FLW ALOFT DEVELOPS WITH
EMBEDDED VORTS AND AREAS OF ENHANCED MID LVL MOISTURE. SOME
UNCERTAINTY WITH REGARDS TO TROF AMPLIFICATION AND POTENTIAL
IMPACTS ACRS OUR CWA. WL MENTION CHC POPS ATTM WITH MORE WEIGHT
TWD THE ECMWF. OTHERWISE...PROGGED 85H TEMPS WARM BTWN
10-12C...SUPPORTING HIGHS BACK INTO THE 70S MTNS TO L/M80S VALLEY
BY THE MID OF NEXT WEEK. LOOK FOR OVERNIGHT LOWS MAINLY IN THE 50S
TO 60S WITH COMFORTABLE RH LVLS.
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
THROUGH 18Z FRIDAY...VFR CONDITIONS WL PREVAIL THIS
AFTN/EVENING...EXCEPT BRIEF PERIODS OF MVFR IN AND AROUND
THUNDERSTORMS. ALSO...ANTICIPATED LIGHTNING AND LOCALIZED GUSTY
WINDS IN THE STRONGER STORMS BTWN 18Z-00Z TODAY. CRNT RADAR TRENDS
SHOW STORMS IMPACTING MSS BY 19Z...WITH OTHER STORMS DEVELOPING
ACRS THE EASTERN DACKS WITH POTENTIAL IMPACTS TO PBG/BTV AND MPV
BTWN 19Z-22Z. HAVE USED TEMPO GROUP TO SHOW 3SM TSRA WITH CIGS BKN
AT 2500 TO 3000 KFT. TONIGHT...AVIATION CHALLENGE WL BE FOG/BR
POTENTIAL...AS LLVL WINDS INCREASE. THINKING MPV/SLK WL HAVE THE
BEST POTENTIAL FOR IFR CONDITIONS AS LLVLS DECOUPLE WITH MVFR
POSSIBLE AT RUT/MSS/BTV...ESPECIALLY IF RAIN OCCURS AT THESE SITES
THIS AFTN.
SOUTH TO SOUTHWEST WINDS WL INCREASE AT 10 TO 15 KNOTS WITH GUSTS
TO 20 TO 25 KNOTS BY FRIDAY MID MORNING.
OUTLOOK 18Z FRIDAY THROUGH MONDAY...SCATTERED AFTN/EVENING
SHOWERS/STORMS AGAIN ON FRIDAY/SATURDAY COULD PRODUCE BRIEF
PERIODS OF MVFR/IFR CONDITIONS. IN ADDITION...GUSTY SOUTHWEST
WINDS AHEAD OF AN APPROACHING COLD FRNT WL CONT ON FRIDAY
AFTN/NIGHT...BEFORE SHIFTING TO THE NORTHWEST ON SAT AFTN.
SUNDAY AND MONDAY...VFR UNDER BUILDING HIGH PRESSURE...EXCEPT
FOG/BR WITH MVFR/IFR AT MPV/SLK EACH MORNING BTWN 06-11Z.
&&
.CLIMATE...
HEAT WAVE HAS BEEN REACHED WITH PAST 3 DAYS MEETING OR EXCEEDING
90F AT KBTV. EXPECT HEAT WAVE TO CONTINUE WITH MAX TEMP OF 90
TODAY AND 94 ON FRIDAY...BEFORE A COLD FRONT APPROACHES ON
SATURDAY.
MAX TEMP RECORDS TODAY THROUGH FRIDAY. BEST SHOT OF REACHING OR
BREAKING RECORD MAX TEMPS ON FRIDAY AT KMPV AND KMSS. SHORTER
PERIOD OF RECORD AT THESE SITES THAN AT K1V4 AND KBTV.
07/18/2013 07/19/2013
KBTV 99/1953 98/1942
KMPV 96/1953 92/1991
K1V4 99/1953 95/1991
KMSS 95/1953 93/1991
&&
.EQUIPMENT...
KTYX IS BACK TO NORMAL OPERATIONS. SLK ASOS IS DOWN DUE TO COMMS
ISSUES...ETS ARE HEADING TO THE SITE AND SHOULD BE FIXED BY MID
AFTERNOON. ALSO...RUTLAND AWOS WILL BE UNAVAIABLE FROM 18 TO 20
UTC TODAY.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...KGM/TABER
NEAR TERM...KGM/LOCONTO
SHORT TERM...KGM
LONG TERM...TABER
AVIATION...TABER
CLIMATE...
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
140 PM EDT THU JUL 18 2013
.SYNOPSIS...
AN ACTIVE WEATHER PATTERN WILL CONTINUE ACROSS THE NORTH COUNTRY
WITH DAILY CHANCES FOR SCATTERED SHOWERS AND THUNDERSTORMS...
ALONG WITH HOT AND HUMID CONDITIONS THROUGH THE END OF THE WEEK.
SOME STORMS COULD BE STRONG TO SEVERE THROUGH THE PERIOD. A COLD
FRONT WILL MOVE THROUGH ON SATURDAY BRINGING MUCH DRIER AND
COOLER AIR FOR SUNDAY AND MONDAY.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
AS OF 107 PM EDT THURSDAY...VISIBLE SATELLITE SHOWS DEVELOPING
CUMULUS/TOWERING CUMULUS CLOUDS ACROSS THE HIGHER TERRAIN...WITH
SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING ACROSS EASTERN
ONTARIO AND IN CENTRAL AND SOUTHERN NEW YORK. AIRMASS ALREADY
QUITE UNSTABLE WITH SBCAPES OF 2500-3500 J/KG PER LATEST RAP AND
LAPS ANALYSIS. BASED ON SATELLITE TRENDS AND THE LACK OF
CONVECTIVE INHIBITION...EXPECT AN INCREASE IN COVERAGE OF SHOWERS
AND THUNDERSTORMS ACROSS NORTHERN NEW YORK THROUGH THE NEXT COUPLE
OF HOURS WITH THIS ACTIVITY DEVELOPING/SPREADING INTO VERMONT BY
LATE AFTERNOON/EVENING. NO CHANGES TO POPS/WEATHER AS THESE ARE
REFLECTED IN THE CURRENT FORECAST...AND STILL BELIEVE ENHANCED
WORDING FOR GUSTY WINDS AND HEAVY RAINFALL IS JUSTIFIED GIVEN
DEGREE OF INSTABILITY AND FAVORABLE DEEP- LAYER SHEAR PROFILES.
PLEASE SEE OUR RECENTLY ISSUED SPECIAL WEATHER STATEMENT TO RAISE
AWARENESS OF POTENTIALLY STRONG THUNDERSTORMS THIS AFTERNOON AND
EVENING.
ENDED UP RAISING TEMPERATURES UP A DEGREE BASED ON CURRENT TRENDS.
STILL EXPECT HIGHS TODAY IN THE UPPER 80S TO LOWER 90S WITH HEAT
INDICES IN THE MID/UPPER 90S.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH SATURDAY/...
AS OF 533 AM EDT THURSDAY...LINGERING CONVECTION THIS EVENING
WITH BR/FG DEVELOPING OVERNIGHT...ESP AT LOCATIONS THAT RECEIVE
RAINFALL. TOWARDS EARLY MORNING HOURS ON FRIDAY...NAM AND GFS
SHOW WARM FRONT LIFTING NWD...BEGINNING THREAT FOR SHOWERS AND
TSTMS EARLY. LLJ AROUND 30-45KTS WILL ACCOMPANY THE
FRONT...PROVIDING PLENTY OF SHEAR TO HELP ORGANIZE CONVECTION.
CAPE VALUES WILL BE EVEN HIGHER WITH OVER 2500 J/KG PSBL AND
SHOWALTER INDEX AROUND -3. CLEARLY DEFINE THETA E RIDGING
SUPPORTS INDICATIONS OF LARGE INSTABILITY OVER THE AREA. WARM
HUMID CONDITIONS CONTINUE ON FRIDAY...BUT FRONT WILL ALSO HAVE
SUPPORT FROM VORTICITY WHICH WILL CONTINUE TO MOVE OVER THE
REGION INTO THE OVERNIGHT. THEREFORE EXPECT BEST CHCS FOR
CONVECTION TO OCCUR ON FRIDAY INTO FRIDAY NIGHT AS MID LEVEL HT
FALLS SEE A MORE DRAMATIC CHANGE FRIDAY NIGHT WHILE UPPER LEVEL
TROUGH GAINS MOMENTUM EWD...GRAZING THE CENTRAL GREAT LAKES AND
PUSHING THE LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT AT THE
SFC FORWARD. GOING INTO SATURDAY...COLD FRONT WILL BE FOCUS OF
SHOWERS AND TSTMS...WITH CAPE OVER 1000 J/KG AND LI AROUND -3C.
UPPER LEVEL JET ACCOMPANYING THE FRONT WILL POSITION THE RR QUAD
OVER THE SLV FRIDAY NIGHT AND MOVE EWD THROUGHOUT THE DAY
SATURDAY. THE COLD FRONT DOESN/T LOOK TO EXIT ERN VT UNTIL LATE
SATURDAY INTO SATURDAY EVENING.
TEMPS WILL BE HOT WITH 925MB REACHING MID20S ON FRIDAY...
RESULTING IN SFC MAX TEMPS IN THE U80S-M90S...ESP IN SW DOWNSLOPE
AREAS LIKE PBG. HEAT INDEX VALUES WILL ONCE AGAIN APPROACH 100
DEGREES IN A FEW LOCATIONS MAINLY IN THE CPV AND CT VALLEY. WITH
MORE CLD COVER ON SATURDAY...EXPECT MAX TEMPS TO BE IN THE
M-U80S. OVERNIGHT MIN TEMPS WILL BE WARM...IN THE 60S- L70S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 407 AM EDT THURSDAY... IT WILL BE NOTICEABLY COOLER AND
DRIER SUNDAY AND MONDAY BEFORE RETURNING TO NEAR NORMAL TUESDAY
AND WEDNESDAY WITH A CHANCE OF SHOWERS AND THUNDERSTORMS.
A BROAD AREA OF CANADIAN HIGH PRESSURE SETTLES INTO THE REGION
SUNDAY INTO MONDAY. 850 TEMPS DROPS TO AROUND 6C BUT MODIFY BACK
TO 8-11C WITH DAYTIME HEATING SO MAX TEMPERATURES EXPECTED IN THE
70S ON SUNDAY AND NIGHTTIME LOWS IN THE 50S WITH KSLK PERHAPS MID
40S.
A BIT MORE UNCERTAIN BY TUE AND WED WITH TIMING OF SHORT WAVE
TROFS WHICH ARE EXPECTED TO CARVE OUT A MEAN LONGER WAVE AND
PERSISTENT TROF SOMEWHERE OVER FROM WESTERN GREAT LAKES INTO THE
NORTHEAST. WE WILL TEND TO BE ON THE ACTIVE SIDE OF THE TROF SO
HAVE BROUGHT A CHANCE OF SHOWERS AND SLIGHT CHANCE OF THUNDER
INTO THE AREA ON TUE-WED. ECMWF IS FASTER THAN GFS/GEFS SO HAVE
TWEAKED THE POPS UP INTO 30 PERCENT RANGE FOR NOW. TEMPERATURES
WILL CREEP UP TO AROUND NORMAL BUT IF IT`S SHOWERY DURING THE
DAY, IT COULD BE A BIT COOLER. LOWS MAINLY 55 TO 65 AND HIGHS 75
TO 82.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
THROUGH 18Z FRIDAY...VFR CONDITIONS WL PREVAIL THIS
AFTN/EVENING...EXCEPT BRIEF PERIODS OF MVFR IN AND AROUND
THUNDERSTORMS. ALSO...ANTICIPATED LIGHTNING AND LOCALIZED GUSTY
WINDS IN THE STRONGER STORMS BTWN 18Z-00Z TODAY. CRNT RADAR TRENDS
SHOW STORMS IMPACTING MSS BY 19Z...WITH OTHER STORMS DEVELOPING
ACRS THE EASTERN DACKS WITH POTENTIAL IMPACTS TO PBG/BTV AND MPV
BTWN 19Z-22Z. HAVE USED TEMPO GROUP TO SHOW 3SM TSRA WITH CIGS BKN
AT 2500 TO 3000 KFT. TONIGHT...AVIATION CHALLENGE WL BE FOG/BR
POTENTIAL...AS LLVL WINDS INCREASE. THINKING MPV/SLK WL HAVE THE
BEST POTENTIAL FOR IFR CONDITIONS AS LLVLS DECOUPLE WITH MVFR
POSSIBLE AT RUT/MSS/BTV...ESPECIALLY IF RAIN OCCURS AT THESE SITES
THIS AFTN.
SOUTH TO SOUTHWEST WINDS WL INCREASE AT 10 TO 15 KNOTS WITH GUSTS
TO 20 TO 25 KNOTS BY FRIDAY MID MORNING.
OUTLOOK 18Z FRIDAY THROUGH MONDAY...SCATTERED AFTN/EVENING
SHOWERS/STORMS AGAIN ON FRIDAY/SATURDAY COULD PRODUCE BRIEF
PERIODS OF MVFR/IFR CONDITIONS. IN ADDITION...GUSTY SOUTHWEST
WINDS AHEAD OF AN APPROACHING COLD FRNT WL CONT ON FRIDAY
AFTN/NIGHT...BEFORE SHIFTING TO THE NORTHWEST ON SAT AFTN.
SUNDAY AND MONDAY...VFR UNDER BUILDING HIGH PRESSURE...EXCEPT
FOG/BR WITH MVFR/IFR AT MPV/SLK EACH MORNING BTWN 06-11Z.
&&
.CLIMATE...
HEAT WAVE HAS BEEN REACHED WITH PAST 3 DAYS MEETING OR EXCEEDING
90F AT KBTV. EXPECT HEAT WAVE TO CONTINUE WITH MAX TEMP OF 90
TODAY AND 94 ON FRIDAY...BEFORE A COLD FRONT APPROACHES ON
SATURDAY.
MAX TEMP RECORDS TODAY THROUGH FRIDAY. BEST SHOT OF REACHING OR
BREAKING RECORD MAX TEMPS ON FRIDAY AT KMPV AND KMSS. SHORTER
PERIOD OF RECORD AT THESE SITES THAN AT K1V4 AND KBTV.
07/18/2013 07/19/2013
KBTV 99/1953 98/1942
KMPV 96/1953 92/1991
K1V4 99/1953 95/1991
KMSS 95/1953 93/1991
&&
.EQUIPMENT...
KTYX IS BACK TO NORMAL OPERATIONS. SLK ASOS IS DOWN DUE TO COMMS
ISSUES...ETS ARE HEADING TO THE SITE AND SHOULD BE FIXED BY MID
AFTERNOON. ALSO...RUTLAND AWOS WILL BE UNAVAIABLE FROM 18 TO 20
UTC TODAY.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...KGM/TABER
NEAR TERM...KGM/LOCONTO
SHORT TERM...KGM
LONG TERM...SISSON
AVIATION...TABER
CLIMATE...
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
108 PM EDT THU JUL 18 2013
.SYNOPSIS...
AN ACTIVE WEATHER PATTERN WILL CONTINUE ACROSS THE NORTH COUNTRY
WITH DAILY CHANCES FOR SCATTERED SHOWERS AND THUNDERSTORMS...
ALONG WITH HOT AND HUMID CONDITIONS THROUGH THE END OF THE WEEK.
SOME STORMS COULD BE STRONG TO SEVERE THROUGH THE PERIOD. A COLD
FRONT WILL MOVE THROUGH ON SATURDAY BRINGING MUCH DRIER AND
COOLER AIR FOR SUNDAY AND MONDAY.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
AS OF 107 PM EDT THURSDAY...VISIBLE SATELLITE SHOWS DEVELOPING
CUMULUS/TOWERING CUMULUS CLOUDS ACROSS THE HIGHER TERRAIN...WITH
SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING ACROSS EASTERN
ONTARIO AND IN CENTRAL AND SOUTHERN NEW YORK. AIRMASS ALREADY
QUITE UNSTABLE WITH SBCAPES OF 2500-3500 J/KG PER LATEST RAP AND
LAPS ANALYSES. BASED ON SATELLITE TRENDS AND THE LACK OF
CONVECTIVE INHIBITION...EXPECT AN INCREASE IN COVERAGE OF SHOWERS
AND THUNDERSTORMS ACROSS NORTHERN NEW YORK THROUGH THE NEXT COUPLE
OF HOURS WITH THIS ACTIVITY DEVELOPING/SPREADING INTO VERMONT BY
LATE AFTERNOON/EVENING. NO CHANGES TO POPS/WEATHER AS THESE ARE
REFLECTED IN THE CURRENT FORECAST...AND STILL BELIEVE ENHANCED
WORDING FOR GUSTY WINDS AND HEAVY RAINFALL IS JUSTIFIED GIVEN
DEGREE OF INSTABILITY AND FAVORABLE DEEP- LAYER SHEAR PROFILES.
PLEASE SEE OUR RECENTLY ISSUED SPECIAL WEATHER STATEMENT TO RAISE
AWARENESS OF POTENTIALLY STRONG THUNDERSTORMS THIS AFTERNOON AND
EVENING.
ENDED UP RAISING TEMPERATURES UP A DEGREE BASED ON CURRENT TRENDS.
STILL EXPECT HIGHS TODAY IN THE UPPER 80S TO LOWER 90S WITH HEAT
INDICES IN THE MID/UPPER 90S.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH SATURDAY/...
AS OF 533 AM EDT THURSDAY...LINGERING CONVECTION THIS EVENING
WITH BR/FG DEVELOPING OVERNIGHT...ESP AT LOCATIONS THAT RECEIVE
RAINFALL. TOWARDS EARLY MORNING HOURS ON FRIDAY...NAM AND GFS
SHOW WARM FRONT LIFTING NWD...BEGINNING THREAT FOR SHOWERS AND
TSTMS EARLY. LLJ AROUND 30-45KTS WILL ACCOMPANY THE
FRONT...PROVIDING PLENTY OF SHEAR TO HELP ORGANIZE CONVECTION.
CAPE VALUES WILL BE EVEN HIGHER WITH OVER 2500 J/KG PSBL AND
SHOWALTER INDEX AROUND -3. CLEARLY DEFINE THETA E RIDGING
SUPPORTS INDICATIONS OF LARGE INSTABILITY OVER THE AREA. WARM
HUMID CONDITIONS CONTINUE ON FRIDAY...BUT FRONT WILL ALSO HAVE
SUPPORT FROM VORTICITY WHICH WILL CONTINUE TO MOVE OVER THE
REGION INTO THE OVERNIGHT. THEREFORE EXPECT BEST CHCS FOR
CONVECTION TO OCCUR ON FRIDAY INTO FRIDAY NIGHT AS MID LEVEL HT
FALLS SEE A MORE DRAMATIC CHANGE FRIDAY NIGHT WHILE UPPER LEVEL
TROUGH GAINS MOMENTUM EWD...GRAZING THE CENTRAL GREAT LAKES AND
PUSHING THE LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT AT THE
SFC FORWARD. GOING INTO SATURDAY...COLD FRONT WILL BE FOCUS OF
SHOWERS AND TSTMS...WITH CAPE OVER 1000 J/KG AND LI AROUND -3C.
UPPER LEVEL JET ACCOMPANYING THE FRONT WILL POSITION THE RR QUAD
OVER THE SLV FRIDAY NIGHT AND MOVE EWD THROUGHOUT THE DAY
SATURDAY. THE COLD FRONT DOESN/T LOOK TO EXIT ERN VT UNTIL LATE
SATURDAY INTO SATURDAY EVENING.
TEMPS WILL BE HOT WITH 925MB REACHING MID20S ON FRIDAY...
RESULTING IN SFC MAX TEMPS IN THE U80S-M90S...ESP IN SW DOWNSLOPE
AREAS LIKE PBG. HEAT INDEX VALUES WILL ONCE AGAIN APPROACH 100
DEGREES IN A FEW LOCATIONS MAINLY IN THE CPV AND CT VALLEY. WITH
MORE CLD COVER ON SATURDAY...EXPECT MAX TEMPS TO BE IN THE
M-U80S. OVERNIGHT MIN TEMPS WILL BE WARM...IN THE 60S- L70S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 407 AM EDT THURSDAY... IT WILL BE NOTICEABLY COOLER AND
DRIER SUNDAY AND MONDAY BEFORE RETURNING TO NEAR NORMAL TUESDAY
AND WEDNESDAY WITH A CHANCE OF SHOWERS AND THUNDERSTORMS.
A BROAD AREA OF CANADIAN HIGH PRESSURE SETTLES INTO THE REGION
SUNDAY INTO MONDAY. 850 TEMPS DROPS TO AROUND 6C BUT MODIFY BACK
TO 8-11C WITH DAYTIME HEATING SO MAX TEMPERATURES EXPECTED IN THE
70S ON SUNDAY AND NIGHTTIME LOWS IN THE 50S WITH KSLK PERHAPS MID
40S.
A BIT MORE UNCERTAIN BY TUE AND WED WITH TIMING OF SHORT WAVE
TROFS WHICH ARE EXPECTED TO CARVE OUT A MEAN LONGER WAVE AND
PERSISTENT TROF SOMEWHERE OVER FROM WESTERN GREAT LAKES INTO THE
NORTHEAST. WE WILL TEND TO BE ON THE ACTIVE SIDE OF THE TROF SO
HAVE BROUGHT A CHANCE OF SHOWERS AND SLIGHT CHANCE OF THUNDER
INTO THE AREA ON TUE-WED. ECMWF IS FASTER THAN GFS/GEFS SO HAVE
TWEAKED THE POPS UP INTO 30 PERCENT RANGE FOR NOW. TEMPERATURES
WILL CREEP UP TO AROUND NORMAL BUT IF IT`S SHOWERY DURING THE
DAY, IT COULD BE A BIT COOLER. LOWS MAINLY 55 TO 65 AND HIGHS 75
TO 82.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
THROUGH 00Z FRIDAY...MAINLY VFR AT KBTV/KPBG. OTHER SITES WILL
HAVE SOME IFR IN BR AND VLIFR AT TIMES IN FOG THROUGH 12Z AT KSLK
AND KMPV. FOG WILL BURN OFF 12-14Z.
NOT EXPECTING TOO MUCH IN THE WAY OF SHOWERS OR THUNDER UNTIL
SCATTERED THUNDERSTORMS DEVELOP GENERALLY AFTER 17Z AND HAVE
INCLUDED VCTS. IF A THUNDERSTORM WERE TO MOVE OVER A TAF SITE I
WOULD EXPECT BRIEF IFR VSBYS AND MVFR CIGS BUT TOO UNCERTAIN TO
INCLUDE AT THIS TIME OF DAY.
CONVECTION EXPECTED TO GRADUALLY DIE OFF TOMORROW NIGHT WITH SOME
BR EXPECTED AFTER 03Z.
WINDS LGT/VAR..THEN W-SW 5-10KTS FROM 13Z-14Z THURSDAY ONWARD.
OUTLOOK 06Z FRIDAY THROUGH MONDAY... 06Z FRIDAY - SAT LCL IFR
FG/BR OVERNIGHT...MAINLY AT KSLK/KMPV. SCATTERED MAINLY AFTERNOON
SHOWERS/THUNDERSTORMS BUT CANT RULE IT OUT AT ANY TIME THROUGH
SAT WITH BRIEF MVFR/IFR VISIBILITIES.
SUNDAY AND MONDAY...VFR UNDER BUILDING HIGH PRESSURE.
&&
.CLIMATE...
HEAT WAVE HAS BEEN REACHED WITH PAST 3 DAYS MEETING OR EXCEEDING
90F AT KBTV. EXPECT HEAT WAVE TO CONTINUE WITH MAX TEMP OF 90
TODAY AND 94 ON FRIDAY...BEFORE A COLD FRONT APPROACHES ON
SATURDAY.
MAX TEMP RECORDS TODAY THROUGH FRIDAY. BEST SHOT OF REACHING OR
BREAKING RECORD MAX TEMPS ON FRIDAY AT KMPV AND KMSS. SHORTER
PERIOD OF RECORD AT THESE SITES THAN AT K1V4 AND KBTV.
07/18/2013 07/19/2013
KBTV 99/1953 98/1942
KMPV 96/1953 92/1991
K1V4 99/1953 95/1991
KMSS 95/1953 93/1991
&&
.EQUIPMENT...
KTYX RADAR FUNCTIONING BUT WE MUST MAINTAIN VCP21 THROUGH AT LEAST THIS
MORNING OR UNTIL A SOLUTION IS FOUND BY THE TECHNICIANS FROM FORT
DRUM.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...KGM/TABER
NEAR TERM...KGM/LOCONTO
SHORT TERM...KGM
LONG TERM...SISSON
AVIATION...SISSON
CLIMATE...
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1015 AM EDT THU JUL 18 2013
.SYNOPSIS...
AN ACTIVE WEATHER PATTERN WILL CONTINUE ACROSS THE NORTH COUNTRY
WITH DAILY CHANCES FOR SCATTERED SHOWERS AND THUNDERSTORMS...
ALONG WITH HOT AND HUMID CONDITIONS THROUGH THE END OF THE WEEK.
SOME STORMS COULD BE STRONG TO SEVERE THROUGH THE PERIOD. A COLD
FRONT WILL MOVE THROUGH ON SATURDAY BRINGING MUCH DRIER AND
COOLER AIR FOR SUNDAY AND MONDAY.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
AS OF 1015 AM EDT THURSDAY...SOME CHANGES WERE MADE TO POPS THIS
MORNING & AFTERNOON AS WELL AS SOME UPWARD TWEAKS TO HOURLY
TEMPERATURES. SEVERAL HIGHLIGHTS TODAY INCLUDING CONTINUED
HOT/HUMID WEATHER AND POTENTIAL FOR STRONG CONVECTION AGAIN THIS
AFTERNOON.
CURRENT RADAR SHOWS SOME ISOLATED SHOWERS ACROSS SOUTHERN
QUEBEC FORMING ALONG A DIFFUSE THERMAL/MOISTURE BOUNDARY NEAR THE
INTERNATIONAL BORDER. THESE SHOWERS MAY SKIRT OUR NORTHERN VT AND
NORTHERN NY COUNTIES THROUGH THE MORNING HOURS. ASIDE FROM THAT
HOWEVER...WEAK SHORTWAVE RIDGING ACROSS THE SOUTHERN TWO-THIRDS OF
THE NORTH COUNTRY WILL KEEP THE REST OF THE NORTH COUNTRY DRY
THROUGH THE REST OF THE MORNING. FOR THE AFTERNOON...THE
AFOREMENTIONED SHORTWAVE RIDGE SHIFTS EAST AS A SUBTLE SHORTWAVE
TROUGH NOW ACROSS THE NORTHERN GREAT LAKES WILL APPROACH THE
REGION FROM THE WEST. THIS IS ALREADY PRODUCING CONVECTION ACROSS
THE NORTHERN LAKES...AND SEE LITTLE REASON TO THINK ADDITIONAL
CONVECTIVE DEVELOPMENT INTO OUR AREA THIS AFTERNOON WON`T HAPPEN
AS THIS TROUGH APPROACHES GIVEN PROJECTED SBCAPES IN THE
1500-3000 J/KG RANGE /HIGHEST WITH SOUTHERN AND WESTERN EXTENT/.
STILL HAVE 0-6KM SHEAR MAGNITUDES OF 30-40KTS AS WELL SO POTENTIAL
FOR SOME STORMS TO BECOME STRONG DURING THE AFTERNOON HOURS. SPC
HAS PLACED MUCH OF NORTHERN NEW YORK AND THE CHAMPLAIN VALLEY IN
A SLIGHT RISK FOR SEVERE THUNDERSTORMS. THOUGH CONVECTIVE MODE IS
TOUGH TO PIN DOWN...SHORT-RANGE REFLECTIVITY GUIDANCE SUGGESTS MOST
OF THE STORMS THAT DEVELOP INITIALLY IN NORTHERN NEW YORK LIFT INTO
NORTHERN/CENTRAL VT LATE IN THE AFTERNOON/EARLY EVENING. SO HAVE
KEPT SCATTERED THUNDERSTORMS WITH GUSTY WINDS AND HEAVY RAINFALL
WORDING IN THE FORECAST FOR THE AFTERNOON.
REGARDING TEMPERATURES...ALREADY STARTING OFF IN THE 70S TO LOW
80S. THOUGH THIS WOULD SUGGEST UPPING HIGHS A COUPLE DEGREES...FEEL
THAT INCREASING MID CLOUD COVER NOW OVER THE NORTHERN LAKES WILL
SPREAD INTO THE NORTH COUNTRY TOWARDS THE AFTERNOON WILL LIKELY
KEEP TEMPERATURES SLIGHTLY COOLER THAN YESTERDAY. THINK CURRENT
HIGHS LOOK ON TRACK WITH THE PROJECTED INCREASE IN CLOUDS BY THE
AFTERNOON. NONETHELESS...STILL WILL BE HOT AND HUMID WITH APPARENT
TEMPERATURES IN THE MID/UPPER 90S.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH SATURDAY/...
AS OF 533 AM EDT THURSDAY...LINGERING CONVECTION THIS EVENING
WITH BR/FG DEVELOPING OVERNIGHT...ESP AT LOCATIONS THAT RECEIVE
RAINFALL. TOWARDS EARLY MORNING HOURS ON FRIDAY...NAM AND GFS
SHOW WARM FRONT LIFTING NWD...BEGINNING THREAT FOR SHOWERS AND
TSTMS EARLY. LLJ AROUND 30-45KTS WILL ACCOMPANY THE
FRONT...PROVIDING PLENTY OF SHEAR TO HELP ORGANIZE CONVECTION.
CAPE VALUES WILL BE EVEN HIGHER WITH OVER 2500 J/KG PSBL AND
SHOWALTER INDEX AROUND -3. CLEARLY DEFINE THETA E RIDGING
SUPPORTS INDICATIONS OF LARGE INSTABILITY OVER THE AREA. WARM
HUMID CONDITIONS CONTINUE ON FRIDAY...BUT FRONT WILL ALSO HAVE
SUPPORT FROM VORTICITY WHICH WILL CONTINUE TO MOVE OVER THE
REGION INTO THE OVERNIGHT. THEREFORE EXPECT BEST CHCS FOR
CONVECTION TO OCCUR ON FRIDAY INTO FRIDAY NIGHT AS MID LEVEL HT
FALLS SEE A MORE DRAMATIC CHANGE FRIDAY NIGHT WHILE UPPER LEVEL
TROUGH GAINS MOMENTUM EWD...GRAZING THE CENTRAL GREAT LAKES AND
PUSHING THE LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT AT THE
SFC FORWARD. GOING INTO SATURDAY...COLD FRONT WILL BE FOCUS OF
SHOWERS AND TSTMS...WITH CAPE OVER 1000 J/KG AND LI AROUND -3C.
UPPER LEVEL JET ACCOMPANYING THE FRONT WILL POSITION THE RR QUAD
OVER THE SLV FRIDAY NIGHT AND MOVE EWD THROUGHOUT THE DAY
SATURDAY. THE COLD FRONT DOESN/T LOOK TO EXIT ERN VT UNTIL LATE
SATURDAY INTO SATURDAY EVENING.
TEMPS WILL BE HOT WITH 925MB REACHING MID20S ON FRIDAY...
RESULTING IN SFC MAX TEMPS IN THE U80S-M90S...ESP IN SW DOWNSLOPE
AREAS LIKE PBG. HEAT INDEX VALUES WILL ONCE AGAIN APPROACH 100
DEGREES IN A FEW LOCATIONS MAINLY IN THE CPV AND CT VALLEY. WITH
MORE CLD COVER ON SATURDAY...EXPECT MAX TEMPS TO BE IN THE
M-U80S. OVERNIGHT MIN TEMPS WILL BE WARM...IN THE 60S- L70S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 407 AM EDT THURSDAY... IT WILL BE NOTICEABLY COOLER AND
DRIER SUNDAY AND MONDAY BEFORE RETURNING TO NEAR NORMAL TUESDAY
AND WEDNESDAY WITH A CHANCE OF SHOWERS AND THUNDERSTORMS.
A BROAD AREA OF CANADIAN HIGH PRESSURE SETTLES INTO THE REGION
SUNDAY INTO MONDAY. 850 TEMPS DROPS TO AROUND 6C BUT MODIFY BACK
TO 8-11C WITH DAYTIME HEATING SO MAX TEMPERATURES EXPECTED IN THE
70S ON SUNDAY AND NIGHTTIME LOWS IN THE 50S WITH KSLK PERHAPS MID
40S.
A BIT MORE UNCERTAIN BY TUE AND WED WITH TIMING OF SHORT WAVE
TROFS WHICH ARE EXPECTED TO CARVE OUT A MEAN LONGER WAVE AND
PERSISTENT TROF SOMEWHERE OVER FROM WESTERN GREAT LAKES INTO THE
NORTHEAST. WE WILL TEND TO BE ON THE ACTIVE SIDE OF THE TROF SO
HAVE BROUGHT A CHANCE OF SHOWERS AND SLIGHT CHANCE OF THUNDER
INTO THE AREA ON TUE-WED. ECMWF IS FASTER THAN GFS/GEFS SO HAVE
TWEAKED THE POPS UP INTO 30 PERCENT RANGE FOR NOW. TEMPERATURES
WILL CREEP UP TO AROUND NORMAL BUT IF IT`S SHOWERY DURING THE
DAY, IT COULD BE A BIT COOLER. LOWS MAINLY 55 TO 65 AND HIGHS 75
TO 82.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
THROUGH 00Z FRIDAY...MAINLY VFR AT KBTV/KPBG. OTHER SITES WILL
HAVE SOME IFR IN BR AND VLIFR AT TIMES IN FOG THROUGH 12Z AT KSLK
AND KMPV. FOG WILL BURN OFF 12-14Z.
NOT EXPECTING TOO MUCH IN THE WAY OF SHOWERS OR THUNDER UNTIL
SCATTERED THUNDERSTORMS DEVELOP GENERALLY AFTER 17Z AND HAVE
INCLUDED VCTS. IF A THUNDERSTORM WERE TO MOVE OVER A TAF SITE I
WOULD EXPECT BRIEF IFR VSBYS AND MVFR CIGS BUT TOO UNCERTAIN TO
INCLUDE AT THIS TIME OF DAY.
CONVECTION EXPECTED TO GRADUALLY DIE OFF TOMORROW NIGHT WITH SOME
BR EXPECTED AFTER 03Z.
WINDS LGT/VAR..THEN W-SW 5-10KTS FROM 13Z-14Z THURSDAY ONWARD.
OUTLOOK 06Z FRIDAY THROUGH MONDAY... 06Z FRIDAY - SAT LCL IFR
FG/BR OVERNIGHT...MAINLY AT KSLK/KMPV. SCATTERED MAINLY AFTERNOON
SHOWERS/THUNDERSTORMS BUT CANT RULE IT OUT AT ANY TIME THROUGH
SAT WITH BRIEF MVFR/IFR VISIBILITIES.
SUNDAY AND MONDAY...VFR UNDER BUILDING HIGH PRESSURE.
&&
.CLIMATE...
HEAT WAVE HAS BEEN REACHED WITH PAST 3 DAYS MEETING OR EXCEEDING
90F AT KBTV. EXPECT HEAT WAVE TO CONTINUE WITH MAX TEMP OF 90
TODAY AND 94 ON FRIDAY...BEFORE A COLD FRONT APPROACHES ON
SATURDAY.
MAX TEMP RECORDS TODAY THROUGH FRIDAY. BEST SHOT OF REACHING OR
BREAKING RECORD MAX TEMPS ON FRIDAY AT KMPV AND KMSS. SHORTER
PERIOD OF RECORD AT THESE SITES THAN AT K1V4 AND KBTV.
07/18/2013 07/19/2013
KBTV 99/1953 98/1942
KMPV 96/1953 92/1991
K1V4 99/1953 95/1991
KMSS 95/1953 93/1991
&&
.EQUIPMENT...
KTYX RADAR FUNCTIONING BUT WE MUST MAINTAIN VCP21 THROUGH AT LEAST THIS
MORNING OR UNTIL A SOLUTION IS FOUND BY THE TECHNICIANS FROM FORT
DRUM.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...KGM/TABER
NEAR TERM...KGM/LOCONTO
SHORT TERM...KGM
LONG TERM...SISSON
AVIATION...SISSON
CLIMATE...
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
100 PM EDT THU JUL 18 2013
.SYNOPSIS...
A WEAK TROUGH OF LOW PRESSURE WILL RESIDE ACROSS THE CAROLINA
INTERIOR INTO THE WEEKEND...WHILE BERMUDA HIGH PRESSURE NUDGES
INTO THE REGION FROM THE WESTERN ATLANTIC. A SLOW MOVING COLD FRONT
WILL STALL ACROSS THE AREA EARLY NEXT WEEK...INCREASING THE CHANCE
OF SHOWERS AND STORMS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 10 AM THURSDAY...CLOCKWISE TURNING OF THE ATMOSPHERE AND
DRIER AIR HAS WORKED INTO THE FORECAST AREA IN THE LAST 12 HOURS
AS AN UPPER RIDGE CONTINUES TO NUDGE EASTWARD. PRECIPITABLE WATER
VALUES HAVE DECREASED OVER A HALF INCH SINCE THIS TIME YESTERDAY
AND SUBSIDENT DOWNWARD MOTION PREVAILS CURRENTLY. THUNDERSTORMS
TO BE CONSIDERABLY MORE HINDERED TODAY...WITH MUCH LESS COVERAGE
AND INTENSITY ANTICIPATED. SEVERAL OF OUR MORE USEFUL NEAR TERM
MODELS SUCH AS THE 3KM HRRR AND 4KM NSSL WRF PAINT SIMILAR OUTCOMES
TODAY...GENERATING ISOLATED TO SCATTERED CONVECTION BETWEEN 2PM AND
3PM INLAND FROM THE COAST...PEAKING IN INTENSITY IN THE LATE AFTN
THEN WEAKENING RAPIDLY WITH DIMINISHED SURFACE HEATING INTO EARLY
EVENING. THIS APPEARS REASONABLE GIVEN THE LACKLUSTER INGREDIENTS
IN PLACE. VAPOR ANALYSIS SHOWS A LOCALLY HIGHER SLUG OF COLUMN
MOISTURE BEING GUIDED INTO COASTAL SOUTH CAROLINA AND THIS MAY
ALLOW MORE ACTIVITY LATER TODAY ACROSS OUR VERY SOUTHERN TIER.
NO MAJOR CHANGES PLANNED TO THE ONGOING FORECAST...AND BECAUSE
OF SLIGHTLY LOWER SFC DEWPOINTS TODAY...HEAT INDICES SHOULD HOLD
MOSTLY BELOW 100...HIGHEST INLAND ASSOCIATED WITH A STRONGER
THERMAL AXIS ALONG THE SANDHILLS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 330 AM THURSDAY...ELONGATED RIDGE IN THE MID TO UPPER
LEVELS EXTENDING FROM THE CAROLINAS ACROSS THE TENNESSEE VALLEY
INTO THE DESERT SOUTHWEST WILL WEAKEN OVER THE EAST THROUGH THE
PERIOD AS TROUGH BEGINS TO DIG DOWN FROM CANADA OVER THE WEEKEND.
BERMUDA RIDGE WILL EXTEND WESTWARD INTO THE CAROLINAS FROM THE
SURFACE UP THROUGH THE LOWER LEVELS OF THE ATMOSPHERE. AT THE SAME
TIME THE PIEDMONT TROUGH REMAINS PRONOUNCED INLAND. THIS WILL
PRODUCE A TIGHTENED GRADIENT FLOW OUT OF THE SOUTH TO SOUTHWEST
FRI INTO SATURDAY. THERE SHOULD BE ENOUGH SUBSIDENCE AND DRY AIR
THROUGH THE MID LEVELS TO HELP SUPPRESS ANY WIDESPREAD CONVECTION
ACROSS THE AREA FRI INTO THE FIRST HALF OF THE WEEKEND. AS THE
RIDGE SHIFTS FARTHER SOUTH THROUGH THE MID TO UPPER LEVELS THE
FLOW ALOFT WILL BEGIN TO SHIFT FROM EASTERLY ON FRI TO NORTH
NORTHWEST FRI NIGHT INTO SATURDAY AND EVENTUALLY WESTERLY BY SAT
NIGHT. THIS WILL ALLOW INCREASING MOISTURE TO ADVECT IN BY THE END
OF THE PERIOD AND WILL ALSO STEER CLOUDS AND SHWRS/TSTMS THAT
DEVELOP INLAND TOWARD THE COAST LATE SATURDAY. THE SOUTHWEST
COMPONENT OF THE FLOW IN THE LOW LEVELS WILL KEEP SEA BREEZE FROM
DRIVING TOO FAR INLAND BY SATURDAY. THIS WILL INCREASE CHC OF
SHOWERS CLOSER TO THE COAST ON SATURDAY BUT OVERALL EXPECT MORE
LIMITED SHWR ACTIVITY THROUGH MUCH OF THE PERIOD. TEMPS WILL
REMAIN VERY WARM TYPICAL OF MID SUMMER WITH READINGS AROUND 90
DURING THE DAY AND LOW TO MID 70S AT NIGHT MOST PLACES.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 330 AM THURSDAY...MORE ACTIVE WEATHER EXPECTED EARLY TO MID
WEEK NEXT WEEK. MID TO UPPER TROUGH WILL CONTINUE TO PUSH A COLD
FRONT TOWARD THE CAROLINAS THROUGH EARLY NEXT WEEK. INCREASING
INSTABILITY AND MOISTURE AHEAD OF THIS FRONT WILL COMBINE WITH
BETTER UPPER LEVEL DYNAMICS TO PRODUCE MORE WIDESPREAD SHWR/TSTMS
ACTIVITY THROUGH THE PERIOD. STILL SOMEWHAT UNCERTAIN AS TO HOW
FAR THE FRONT WILL MAKE IT BUT LATEST GFS SHOWS THIS BOUNDARY
REACHING INTO NORTH CAROLINA BY EARLY MONDAY AND POSSIBLY
REMAINING OVER THE CAROLINAS THROUGH MID WEEK. DECENT MID TO UPPER
LEVEL SHORTWAVE ENERGY WILL RIDE THROUGH LONGER WAVE TROUGH
REACHING DOWN FROM CANADA THROUGH EARLY TO MID WEEK. THIS WILL
ENHANCE SHWR/TSTM ACTIVITY EACH DAY. INCREASED CLOUDINESS AND
CONVECTION WILL LEAD TO FLUCTUATIONS IN TEMPS THROUGH THE DAY BUT
OVERALL EXPECT READINGS RIGHT NEAR OR ABOVE NORMAL...AROUND 90
DURING THE DAY AND HOLDING IN THE LOWER TO MID 70S OVERNIGHT.
&&
.AVIATION /18Z THURSDAY THROUGH MONDAY/...
AS OF 17Z...ISOLATED CONVECTION WILL FIRE OVER PORTIONS OF THE CWA
THIS AFTERNOON. THE COAST WILL LIKELY BE SPARED...WITH ONLY ISOLATED
CONVECTION INLAND. WILL GO WITH A VCSH MENTION ONLY. LIGHT SOUTHERLY
FLOW...A BIT MORE SOUTHEASTERLY ALONG THE COAST. LIGHT WINDS TONIGHT
WITH SOME MVFR FOG EXPECTED BY AFTER 08Z. WINDS ALOFT WILL BE A BIT
STRONGER THAN YESTERDAY...SO DUE NOT EXPECT ANY DENSE FOG. LIGHT
SOUTHWESTERLY FLOW EXPECTED FRIDAY WITH CONVECTION EXPECTED AFTER
THE END OF THE FORECAST PERIOD.
EXTENDED OUTLOOK...EARLY MORNING FOG POSSIBLE DURING THE EXTENDED
PERIOD. INCREASING CHANCES FOR SHOWERS/T-STORMS SATURDAY THROUGH
MONDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 10 AM THURSDAY...WEAK SFC PRESSURE PATTERN AND GRADIENT TODAY
TO EVOLVE INTO MORE OF A SFC BERMUDA HIGH REGIME TONIGHT AND INTO
THE SHORT TERM. THE SFC RIDGING WILL EXTEND WESTWARD FROM THE SFC
HIGH WELL OFFSHORE...TO THE SE U.S. COAST TONIGHT. THE SFC RIDGE
AXIS TO REMAIN SOUTH OF THE ILM CWA. SOMEWHAT VARIABLE WIND
DIRECTIONS TODAY...WITH A LACK OF A SFC PG YIELDING LESS THAN 10 KT
FOR SPEEDS. THE EXCEPTION WILL BE ESPECIALLY NEAR SHORE WHERE THE
SEA BREEZE CIRCULATION WILL BE THE PRIMARY EMPHASIS FOR WIND DIR AND
SPEEDS FROM MIDDAY THROUGH EARLY THIS EVENING. FOR THE OVERNIGHT
PERIOD...SSW-SW WIND WILL BECOME MORE DOMINANT WITH THE SFC PG
YIELDING A RATHER SOLID 10-15 KT WIND SPEED. SIGNIFICANT SEAS WILL
RANGE BETWEEN 2 TO 3 FEET THROUGH THE FORECAST PERIOD...WITH AVERAGE
PERIODS BETWEEN 5 AND 6 SECONDS.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 330 AM THURSDAY...PIEDMONT TROUGH OVER INLAND CAROLINAS WILL
COMBINE WITH BERMUDA HIGH EXTENDING INTO THE WATERS FROM THE EAST
TO PRODUCE SOUTHERLY WINDS THROUGH THE PERIOD. THE WINDS INITIALLY
WILL BE 10 TO 15 KTS ON FRI WITH SEAS HOLDING AROUND 3 FT OR LESS.
GRADIENT WILL TIGHTEN AND WINDS WILL VEER TO THE SOUTHWEST AS COLD
FRONT PUSHES SOUTHWEST TOWARD THE CAROLINAS THROUGH THE WEEKEND.
EXPECT WINDS TO INCREASE UP TO 15 TO 20 KTS INTO SATURDAY. THIS
PERSISTENT SOUTHERLY FLOW WILL PUSH SEAS UP TO 3 TO 5 FT MOST
WATERS. THE STRENGTH OF THE WINDS WILL VARY DEPENDING ON HOW FAR
SOUTH AND EAST THE FRONT MAKES IT. LATEST RUNS HOLDING BACK ON
SOUTHWARD PROGRESSION OF COLD FRONT AND THEREFORE MAY NOT SEE THE
WINDS INCREASE AS MUCH AS PREVIOUSLY FORECAST. THIS WILL KEEP SEAS
SLIGHTLY LOWER HOLDING BELOW SCA THRESHOLDS IF FRONT HOLDS TO THE
NORTHWEST. WNA SHOWS STEADY INCREASE IN SEAS FRI EVENING THROUGH
SAT EVENING WITH SEAS PEAKING AROUND 5 TO 6 FT IN OUTER WATERS BY
SAT EVENING.
LONG TERM /SUNDAY THROUGH MONDAY/...
AS OF 330 AM THURSDAY...COLD FRONT MAY LINGER INLAND AND WEAKEN
THROUGH THE PERIOD. THEREFORE TIGHTENED GRADIENT FLOW BETWEEN
BERMUDA HIGH TO THE EAST AND FRONT TO THE WEST WILL RELAX THROUGH
MONDAY AS FRONT WEAKENS. EXPECT WINDS INITIALLY UP TO 15 TO 20 KTS
DECREASING DOWN CLOSER TO 15 KTS OR LESS BY MONDAY. WINDS MAY VEER
SLIGHTLY MORE WESTERLY SUN NIGHT INTO MON DEPENDING ON HOW CLOSE
THE FRONT MAKES IT. PERSISTENT SOUTHERLY FLOW WILL KEEP SEAS 3 TO
5 FT THROUGH MOST OF THE PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DCH/8
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...DL/8
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1000 AM EDT THU JUL 18 2013
.SYNOPSIS...
A WEAK TROUGH OF LOW PRESSURE WILL RESIDE ACROSS THE CAROLINA
INTERIOR INTO THE WEEKEND...WHILE BERMUDA HIGH PRESSURE NUDGES
INTO THE REGION FROM THE WESTERN ATLANTIC. A SLOW MOVING COLD FRONT
WILL STALL ACROSS THE AREA EARLY NEXT WEEK...INCREASING THE CHANCE
OF SHOWERS AND STORMS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 10 AM THURSDAY...CLOCKWISE TURNING OF THE ATMOSPHERE AND
DRIER AIR HAS WORKED INTO THE FORECAST AREA IN THE LAST 12 HOURS
AS AN UPPER RIDGE CONTINUES TO NUDGE EASTWARD. PRECIPITABLE WATER
VALUES HAVE DECREASED OVER A HALF INCH SINCE THIS TIME YESTERDAY
AND SUBSIDENT DOWNWARD MOTION PREVAILS CURRENTLY. THUNDERSTORMS
TO BE CONSIDERABLY MORE HINDERED TODAY...WITH MUCH LESS COVERAGE
AND INTENSITY ANTICIPATED. SEVERAL OF OUR MORE USEFUL NEAR TERM
MODELS SUCH AS THE 3KM HRRR AND 4KM NSSL WRF PAINT SIMILAR OUTCOMES
TODAY...GENERATING ISOLATED TO SCATTERED CONVECTION BETWEEN 2PM AND
3PM INLAND FROM THE COAST...PEAKING IN INTENSITY IN THE LATE AFTN
THEN WEAKENING RAPIDLY WITH DIMINISHED SURFACE HEATING INTO EARLY
EVENING. THIS APPEARS REASONABLE GIVEN THE LACKLUSTER INGREDIENTS
IN PLACE. VAPOR ANALYSIS SHOWS A LOCALLY HIGHER SLUG OF COLUMN
MOISTURE BEING GUIDED INTO COASTAL SOUTH CAROLINA AND THIS MAY
ALLOW MORE ACTIVITY LATER TODAY ACROSS OUR VERY SOUTHERN TIER.
NO MAJOR CHANGES PLANNED TO THE ONGOING FORECAST...AND BECAUSE
OF SLIGHTLY LOWER SFC DEWPOINTS TODAY...HEAT INDICES SHOULD HOLD
MOSTLY BELOW 100...HIGHEST INLAND ASSOCIATED WITH A STRONGER
THERMAL AXIS ALONG THE SANDHILLS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 330 AM THURSDAY...ELONGATED RIDGE IN THE MID TO UPPER
LEVELS EXTENDING FROM THE CAROLINAS ACROSS THE TENNESSEE VALLEY
INTO THE DESERT SOUTHWEST WILL WEAKEN OVER THE EAST THROUGH THE
PERIOD AS TROUGH BEGINS TO DIG DOWN FROM CANADA OVER THE WEEKEND.
BERMUDA RIDGE WILL EXTEND WESTWARD INTO THE CAROLINAS FROM THE
SURFACE UP THROUGH THE LOWER LEVELS OF THE ATMOSPHERE. AT THE SAME
TIME THE PIEDMONT TROUGH REMAINS PRONOUNCED INLAND. THIS WILL
PRODUCE A TIGHTENED GRADIENT FLOW OUT OF THE SOUTH TO SOUTHWEST
FRI INTO SATURDAY. THERE SHOULD BE ENOUGH SUBSIDENCE AND DRY AIR
THROUGH THE MID LEVELS TO HELP SUPPRESS ANY WIDESPREAD CONVECTION
ACROSS THE AREA FRI INTO THE FIRST HALF OF THE WEEKEND. AS THE
RIDGE SHIFTS FARTHER SOUTH THROUGH THE MID TO UPPER LEVELS THE
FLOW ALOFT WILL BEGIN TO SHIFT FROM EASTERLY ON FRI TO NORTH
NORTHWEST FRI NIGHT INTO SATURDAY AND EVENTUALLY WESTERLY BY SAT
NIGHT. THIS WILL ALLOW INCREASING MOISTURE TO ADVECT IN BY THE END
OF THE PERIOD AND WILL ALSO STEER CLOUDS AND SHWRS/TSTMS THAT
DEVELOP INLAND TOWARD THE COAST LATE SATURDAY. THE SOUTHWEST
COMPONENT OF THE FLOW IN THE LOW LEVELS WILL KEEP SEA BREEZE FROM
DRIVING TOO FAR INLAND BY SATURDAY. THIS WILL INCREASE CHC OF
SHOWERS CLOSER TO THE COAST ON SATURDAY BUT OVERALL EXPECT MORE
LIMITED SHWR ACTIVITY THROUGH MUCH OF THE PERIOD. TEMPS WILL
REMAIN VERY WARM TYPICAL OF MID SUMMER WITH READINGS AROUND 90
DURING THE DAY AND LOW TO MID 70S AT NIGHT MOST PLACES.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 330 AM THURSDAY...MORE ACTIVE WEATHER EXPECTED EARLY TO MID
WEEK NEXT WEEK. MID TO UPPER TROUGH WILL CONTINUE TO PUSH A COLD
FRONT TOWARD THE CAROLINAS THROUGH EARLY NEXT WEEK. INCREASING
INSTABILITY AND MOISTURE AHEAD OF THIS FRONT WILL COMBINE WITH
BETTER UPPER LEVEL DYNAMICS TO PRODUCE MORE WIDESPREAD SHWR/TSTMS
ACTIVITY THROUGH THE PERIOD. STILL SOMEWHAT UNCERTAIN AS TO HOW
FAR THE FRONT WILL MAKE IT BUT LATEST GFS SHOWS THIS BOUNDARY
REACHING INTO NORTH CAROLINA BY EARLY MONDAY AND POSSIBLY
REMAINING OVER THE CAROLINAS THROUGH MID WEEK. DECENT MID TO UPPER
LEVEL SHORTWAVE ENERGY WILL RIDE THROUGH LONGER WAVE TROUGH
REACHING DOWN FROM CANADA THROUGH EARLY TO MID WEEK. THIS WILL
ENHANCE SHWR/TSTM ACTIVITY EACH DAY. INCREASED CLOUDINESS AND
CONVECTION WILL LEAD TO FLUCTUATIONS IN TEMPS THROUGH THE DAY BUT
OVERALL EXPECT READINGS RIGHT NEAR OR ABOVE NORMAL...AROUND 90
DURING THE DAY AND HOLDING IN THE LOWER TO MID 70S OVERNIGHT.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
AS OF 14Z...DENSE FOG IN SPOTS WILL MIX OUT BY 13Z OR SO. LARGE
THUNDERSTORM COMPLEX MOVED OUT OF THE REGION LAST NIGHT. THE
ATMOSPHERE IS PRETTY WORKED OVER...BUT THE SAME BOUNDARY THAT FIRED
THE CONVECTION YESTERDAY IS STILL AROUND...VISIBLE ON WATER VAPOR.
WE SHOULD SEE SOME ISOLATED/SCATTERED ACTIVITY THIS
AFTERNOON...FOCUSED MAINLY AT THE RESULTANT AND ALONG THE PIEDMONT
TROUGH. LIGHT AND VARIABLE WINDS THIS MORNING WILL GIVE WAY TO A
MAINLY SOUTHERLY COMPONENT BY MIDDAY.
EXTENDED OUTLOOK...EARLY MORNING FOG POSSIBLE DURING THE EXTENDED
PERIOD. INCREASING CHANCES FOR SHOWERS/T-STORMS SATURDAY THROUGH
MONDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 10 AM THURSDAY...WEAK SFC PRESSURE PATTERN AND GRADIENT TODAY
TO EVOLVE INTO MORE OF A SFC BERMUDA HIGH REGIME TONIGHT AND INTO
THE SHORT TERM. THE SFC RIDGING WILL EXTEND WESTWARD FROM THE SFC
HIGH WELL OFFSHORE...TO THE SE U.S. COAST TONIGHT. THE SFC RIDGE
AXIS TO REMAIN SOUTH OF THE ILM CWA. SOMEWHAT VARIABLE WIND
DIRECTIONS TODAY...WITH A LACK OF A SFC PG YIELDING LESS THAN 10 KT
FOR SPEEDS. THE EXCEPTION WILL BE ESPECIALLY NEAR SHORE WHERE THE
SEA BREEZE CIRCULATION WILL BE THE PRIMARY EMPHASIS FOR WIND DIR AND
SPEEDS FROM MIDDAY THROUGH EARLY THIS EVENING. FOR THE OVERNIGHT
PERIOD...SSW-SW WIND WILL BECOME MORE DOMINANT WITH THE SFC PG
YIELDING A RATHER SOLID 10-15 KT WIND SPEED. SIGNIFICANT SEAS WILL
RANGE BETWEEN 2 TO 3 FEET THROUGH THE FORECAST PERIOD...WITH AVERAGE
PERIODS BETWEEN 5 AND 6 SECONDS.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 330 AM THURSDAY...PIEDMONT TROUGH OVER INLAND CAROLINAS WILL
COMBINE WITH BERMUDA HIGH EXTENDING INTO THE WATERS FROM THE EAST
TO PRODUCE SOUTHERLY WINDS THROUGH THE PERIOD. THE WINDS INITIALLY
WILL BE 10 TO 15 KTS ON FRI WITH SEAS HOLDING AROUND 3 FT OR LESS.
GRADIENT WILL TIGHTEN AND WINDS WILL VEER TO THE SOUTHWEST AS COLD
FRONT PUSHES SOUTHWEST TOWARD THE CAROLINAS THROUGH THE WEEKEND.
EXPECT WINDS TO INCREASE UP TO 15 TO 20 KTS INTO SATURDAY. THIS
PERSISTENT SOUTHERLY FLOW WILL PUSH SEAS UP TO 3 TO 5 FT MOST
WATERS. THE STRENGTH OF THE WINDS WILL VARY DEPENDING ON HOW FAR
SOUTH AND EAST THE FRONT MAKES IT. LATEST RUNS HOLDING BACK ON
SOUTHWARD PROGRESSION OF COLD FRONT AND THEREFORE MAY NOT SEE THE
WINDS INCREASE AS MUCH AS PREVIOUSLY FORECAST. THIS WILL KEEP SEAS
SLIGHTLY LOWER HOLDING BELOW SCA THRESHOLDS IF FRONT HOLDS TO THE
NORTHWEST. WNA SHOWS STEADY INCREASE IN SEAS FRI EVENING THROUGH
SAT EVENING WITH SEAS PEAKING AROUND 5 TO 6 FT IN OUTER WATERS BY
SAT EVENING.
LONG TERM /SUNDAY THROUGH MONDAY/...
AS OF 330 AM THURSDAY...COLD FRONT MAY LINGER INLAND AND WEAKEN
THROUGH THE PERIOD. THEREFORE TIGHTENED GRADIENT FLOW BETWEEN
BERMUDA HIGH TO THE EAST AND FRONT TO THE WEST WILL RELAX THROUGH
MONDAY AS FRONT WEAKENS. EXPECT WINDS INITIALLY UP TO 15 TO 20 KTS
DECREASING DOWN CLOSER TO 15 KTS OR LESS BY MONDAY. WINDS MAY VEER
SLIGHTLY MORE WESTERLY SUN NIGHT INTO MON DEPENDING ON HOW CLOSE
THE FRONT MAKES IT. PERSISTENT SOUTHERLY FLOW WILL KEEP SEAS 3 TO
5 FT THROUGH MOST OF THE PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DCH/MJC
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...DL
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
250 PM CDT THU JUL 18 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 250 PM CDT THU JUL 18 2013
SEVERE POTENTIAL THIS EVENING WILL BE THE MAIN CONCERN. HEAT
ADVISORY CONDITIONS ACROSS THE SOUTHERN FA WILL CONTINUE INTO THE
EARLY EVENING HOURS. THE MAIN SEVERE RISK AREA WILL BE ALONG THE
WARM FRONT FROM JUST EAST OF GRAND FORKS INTO BEMIDJI...AND
LOCATIONS 50 MILES NORTH AND SOUTH OF THIS LINE. SPC SUPERCELL
COMPOSITE AND SIGNIFICANT TORNADO PARAMETERS INDICATE THIS AREA
WITH THE GREATEST POTENTIAL. 19Z LAPS ANALYSIS STILL INDICATES A
STRONG CAP (MLCIN AOA 40 J/KG)...AND NOT SURE HOW WIDESPREAD
INITIATION WILL BE. HRRR HAS BEEN CONSISTENT WITH DEVELOPING
STORMS...AND WILL CONTINUE TO FOLLOW ITS COVERAGE AND INITIATION
TIMES. ANTICIPATE SUPERCELL STORMS CAPABLE OF ALL MODES OF SEVERE
WEATHER. THERE IS ANOTHER AREA OF CONCERN ACROSS THE NW FA AS THE
UPPER WAVE APPROACHES THIS EVENING. AN AREA OF STORMS HAS
DEVELOPED WELL TO THE NW IN SASKATCHEWAN (JUST AHEAD OF THE UPPER
WAVE)...AND INSTABILITY SHOULD INCREASE JUST AHEAD OF THIS
COMPLEX. THIS COMPLEX MAY STILL BE SEVERE AS IT MOVES INTO THE NW
FA...AND QUICKLY WEAKEN BY MIDNIGHT.
FRIDAY-FRIDAY NIGHT...ANOTHER COLD FRONT WILL MOVE INTO THE REGION
ON FRIDAY. INSTABILITY WILL BE WEAK...BUT SHOULD BE ENOUGH FOR
ISOLD SHOWERS AND POSSIBLY THUNDER FRIDAY AFTERNOON. SFC HIGH
PRESSURE WILL BEGIN WORKING INTO THE REGION FROM THE NE FRIDAY
NIGHT...AND MIN TEMPS BY SATURDAY MORNING SHOULD BE INTO THE 40S
ACROSS NE MN (WARMER TO THE WEST AND SOUTH).
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 250 PM CDT THU JUL 18 2013
SATURDAY-SUNDAY...MODELS AGREE WITH NORTHWEST FLOW ALOFT AND
SURFACE RIDGING ACROSS MUCH OF THE FA. THE SURFACE RIDGE GRADUALLY
SHIFTS BACK TO THE EAST BY SUNDAY. THUNDER CHANCES WILL BE ON THE
WESTERN EDGE OF THE FA ON SATURDAY...AND SHIFT TO THE EAST BY
SUNDAY. FORCING AND INSTABILITY WILL BE WEAK...SO EXPECT ONLY
ISOLD TO SCATTERED ACTIVITY. TEMPERATURES WILL BE BELOW NORMAL
VALUES AS A RELATIVELY COLDER AIRMASS WILL BE ACROSS THE REGION.
SUNDAY NIGHT-THURSDAY...LONG TERM MODELS ARE IN POOR AGREEMENT.
IN GENERAL...ECMWF TRACK OF SFC LOWS TRANSITING SOUTHERN CANADA
NEXT WEEK ARE MUCH FURTHER NORTH THAN THE GFS...WHICH BRINGS THEM
ACROSS NORTHERN TIER OF CONUS. ECMWF ALSO CONTINUES TO PRODUCE A
LOT OF QPF...WHICH SEEMS UNREALISTIC. THEY DO AGREE SOMEWHAT ON A
NW FLOW UPPER AIR PATTERN BUT EVEN THAT DIVERGES BY DAY 6. THUS
LOW POPS IN CONSALL IS A RESULT OF ECMWF BLENDED INTO THE
SOLUTION. CONFIDENCE IS LOW BEYOND DAY 4 (NIGHT). BEST CHANCE
APPEARS TO BE SUN NIGHT INTO MON MORNING...WHEN AN UPPER WAVE
MOVES ACROSS THE AREA. BEST CHANCES WILL BE ACROSS THE NORTHEAST
AND DO HAVE A FAIR DEGREE OF CONFIDENCE FOR 40S POPS ACROSS THE
NORTH. GFS WOULD THEN GIVE US DRY WEATHER MON NIGHT AND I HAVE
REMOVED CHANCE POPS FOR THIS PERIOD. GFS THEN BRINGS ANOTHER SFC
LOW INTO NORTHERN TIER TUE NIGHT...FOR ANOTHER CHANCE OF
SHOWERS/TSTMS ACROSS THE NORTH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1240 PM CDT THU JUL 18 2013
WARM FRONT CURRENTLY OVER NORTH CENTRAL VALLEY WILL BEGIN TO DROP
SOUTHEAST THIS AFTN...AND WILL ADD VCTS TO BJI AND FAR FOR BRIEF
PERIOD THIS AFTN. 4KM WRF SHOWS CONVECTION AS A NARROW BAND AND HAS
BEEN PERFORMING WELL...BUT IF MID LEVELS DESTABILIZE COULD EASILY
SEE SOME TSTMS IN VCNTY OF OTHER TAF SITES. SECONDARY SHOT OF
SHOWERS/TSTMS WILL MOVE ACROSS AREA LATE EVENING INTO THE
OVERNIGHT PERIOD. WILL KEEP MAINLY VCSH AS CONFIDENCE NOT HIGH
ENOUGH YET TO GO PREDOMINANT. DO EXPECT VFR CIGS WITH ANY
ACTIVITY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR NDZ038-039-049-052-
053.
MN...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR MNZ003-027>031-040.
&&
$$
SHORT TERM...TG
LONG TERM...TG/SPEICHER
AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS BISMARCK ND
101 PM CDT THU JUL 18 2013
.UPDATE...
ISSUED AT 101 PM CDT THU JUL 18 2013
HEAT INDICES APPROACHING 100F OVER THE JAMES RIVER BASIN IS STILL
FORECAST FOR THIS AFTERNOON. AS A RESULT...WILL MAINTAIN THE HEAT
ADVISORY FOR THE JAMES RIVER BASIN THIS AFTERNOON.
MSAS ANALYZED A SURFACE CYCLONE CENTERED OVER GRAND FORKS AT 17Z.
LAPS ANALYZED INCREASING SURFACE-BASED CAPE (AROUND 2500 J/KG) IN
THE WARM SECTOR OF THE SURFACE LOW ACROSS SOUTH CENTRAL AND
SOUTHEASTERN NORTH DAKOTA. THE 16Z HRRR-3KM CONTINUES TO DEVELOP
SCATTERED THUNDERSTORMS ACROSS THE JAMES RIVER VALLEY BETWEEN 21Z-
00Z THIS AFTERNOON. HOWEVER...COVERAGE AND INTENSITY IS LESS THAN
PREVIOUS RUNS WOULD SUGGEST DUE TO THE CAP. STILL CANNOT TOTALLY
RULE OUT THE POSSIBILITY OF A SEVERE STORM THIS AFTERNOON. WILL
MAINTAIN MENTION IN THE HWO FOR NOW AS A RESULT.
SHIFTING FOCUS NORTH...A LINE OF CONVECTION IS ALREADY FIRING OVER
SOUTH-CENTRAL SASKATCHEWAN. BASED ON THE CURRENT TRAJECTORY...THIS
ACTIVITY WILL BE NEAR THE ND/CANADIAN BORDER BETWEEN 23Z-00Z.
STILL THINK NORTH CENTRAL NORTH DAKOTA COULD SEE SEVERE STORMS
BETWEEN 00Z-03Z TONIGHT. WILL CONTINUE TO MENTION THIS POSSIBILITY
IN THE HWO.
UPDATE ISSUED AT 1027 AM CDT THU JUL 18 2013
SOUTHWESTERLY FLOW ACROSS SOUTH CENTRAL AND SOUTHEASTERN NORTH
DAKOTA IS STILL FORECAST TO GENERATE HEAT INDICES APPROACHING 100F
OVER THE JAMES RIVER BASIN THIS AFTERNOON. AS A RESULT...WILL
MAINTAIN THE HEAT ADVISORY FOR THE JAMES RIVER BASIN THIS
AFTERNOON.
MSAS ANALYSIS SHOWS A SURFACE COLD FRONT EXTENDING FROM AROUND
MAYVILLE TO STEELE TO FORT YATES. LAPS ANALYSIS INDICATES
INCREASING SURFACE-BASED CAPE AROUND 1500 J/KG AHEAD OF THE COLD
FRONT OVER THE JAMES RIVER VALLEY. AS THE FRONT PUSHES ACROSS
NORTH DAKOTA TODAY...SHORT RANGE HIGH RES MODEL GUIDANCE PROGS
SCATTERED CONVECTION TO BEGIN OVER THE JAMES RIVER BASIN AROUND
20Z AND PUSH INTO THE SOUTHERN RED RIVER VALLEY THROUGH 00Z.
MARGINAL DEEP LAYER SHEAR IS THE ONLY INGREDIENT LIMITING
CONFIDENCE IN STORMS BECOMING SEVERE. AS A RESULT...WILL KEEP
SEVERE MENTION OUT OF THE ZONES...BUT KEEP IT IN THE HWO.
FARTHER NORTH...AN UPPER LEVEL WAVE IS EXPECTED TO TRIGGER
THUNDERSTORMS OVER THE SOUTHERN CANADIAN PRAIRIES LATER THIS
AFTERNOON. THE 3KM HRRR AND 00Z WRF PROG THIS ACTIVITY TO
PROPAGATE INTO NORTH CENTRAL NORTH DAKOTA AFTER 00Z THIS EVENING.
GIVEN THE STRONG UPPER FORCING AND POSSIBLE MCS
MAINTENANCE/PROPAGATION...NORTH CENTRAL NORTH DAKOTA COULD SEE
SEVERE STORMS BETWEEN 00Z-03Z TONIGHT. WILL CONTINUE TO MENTION
THIS POSSIBILITY IN THE HWO.
UPDATE ISSUED AT 648 AM CDT THU JUL 18 2013
ELEVATED CONVECTION THAT DEVELOPED OVERNIGHT IN FAR NORTHWEST
NORTH DAKOTA HAS MOVED EAST OUT OF THE FORECAST AREA. THEREFORE WE
HAVE REMOVED THE POPS ACROSS THE FAR NORTH CENTRAL FOR THIS
MORNING. OTHERWISE MINIMAL UPDATES THIS MORNING. DID REDUCE CLOUD
COVER A BIT ACROSS WITH THE EXITING PRECIPITATION AND RAISED IT A
BIT OVER THE SOUTHWEST AS MID LEVEL CLOUDS MOVE INTO THIS AREA
AHEAD OF A MID LEVEL SHORTWAVE. AS THE SHORTWAVE MOVES ACROSS THE
SOUTHERN PRAIRIE PROVINCES OF CANADA TODAY CONVECTION IS EXPECTED
TO DEVELOP ACROSS THE NORTHERN TIER COUNTIES LATE THIS AFTERNOON
AND POSSIBLY ALONG THE SURFACE TROUGH IN THE SOUTH CENTRAL BY
EARLY TO MID AFTERNOON. CURRENT FORECAST HAS THIS COVERED. NO
CHANGES TO THE CURRENT HEAT ADVISORY OVER THE JAMES RIVER VALLEY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 313 AM CDT THU JUL 18 2013
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE CHANCES FOR
THUNDERSTORMS NORTH AND SOUTH AND VERY WARM AND HUMID CONDITIONS
SOUTH CENTRAL AND SOUTHEAST.
CURRENTLY...ZONAL FLOW ALOFT WITH AN EMBEDDED S/WV MOVING EAST
ALONG THE INTERNATIONAL BORDER. ONGOING EARLY MORNING CONVECTION
FAR NORTH WILL START TO PUSH OFF TO THE NORTH AND EAST NOW THROUGH
12Z AS THE MID LEVEL ENERGY PUSHES EAST AND THE INFLUENCE OF A
NOCTURNAL LOW LEVEL JET DECREASES WITH TIME.
FOR THE REST OF THIS MORNING...AFTER THE EARLY MORNING CONVECTION
NORTH...WE LOOK TO BE MAINLY DRY UNTIL MID TO LATE MORNING WHEN
MODELS SUGGEST PRECIPITATION DEVELOPING OVER SOUTHEASTERN MONTANA
AND PERHAPS AS FAR EAST AS FAR SOUTHWEST NORTH DAKOTA AS AN
UPSLOPE FLOW MATERIALIZES.
SFC TROUGH AXIS THURSDAY AFTERNOON WILL BE ORIENTATED FROM THE
BLACK HILLS OF SOUTH DAKOTA NORTHEAST INTO THE CENTRAL RED RIVER
VALLEY OF EASTERN NORTH DAKOTA. WHILE MID LEVEL FORCING IS
EXPECTED TO BE WEAK OVER NORTH DAKOTA WITH NO REAL WAVE FEATURED
IN MODELS UNTIL LATER IN THE DAY ACROSS THE NORTH...MAY BE ENOUGH
LOW LEVEL FORCING/CONVERGENCE ALONG THE TROUGH AXIS TO GENERATE
DAYTIME THUNDERSTORMS OVER MY SOUTHERN COUNTIES WITH PLENTY OF
INSTABILITY EXPECTED TO BE IN PLACE.
CHANCES FOR THUNDERSTORMS INCREASE ACROSS THE NORTH AND DEVELOP
EAST AND SLIGHTLY SOUTH MID TO LATE AFTERNOON AS A MID LEVEL S/WV
TROUGH MOVES EAST-SOUTHEAST INTO SOUTHERN SASKATCHEWAN 21-00Z AND
INTO NORTHERN NORTH DAKOTA THURSDAY EVENING. COVERAGE AND CHANCES
FOR THUNDERSTORMS DECREASE AFTER 06Z WITH THE WAVE CONTINUING TO
TRACK SOUTHEAST TOWARDS/INTO WESTERN MINNESOTA. WILL CONTINUE TO
MENTION THE POSSIBILITY OF SEVERE THUNDERSTORMS IN THE HWO.
BESIDES THUNDERSTORM CHANCES TODAY...BOUNDARY LAYER TEMPERATURES
APPROACHING 30C ACROSS THE SOUTH WILL RESULT IN AFTERNOON
TEMPERATURES IN THE 90S ALONG AND SOUTH OF INTERSTATE 94...WITH
THE WARMEST TEMPERATURES FAR SOUTH CENTRAL AND SOUTH EAST WHERE
HIGHS ARE FORECAST TO CLIMB TO OVER 95F. COMBINED WITH SFC
DEWPOINTS 65-70F...HEAT INDICES WILL APPROACH 100F OVER THE JAMES
RIVER BASIN AND REACH INTO THE UPPER 90S FAR SOUTH CENTRAL. WILL
THUS MAINTAIN THE HEAT ADVISORY FOR THE JAMES RIVER BASIN FOR THIS
AFTERNOON WHERE THE HIGHEST HEAT INDEX IS EXPECTED...AND LEAVE
THE FAR SOUTH CENTRAL OUT FOR NOW AS THEY ARE...AT THIS FORECAST
ISSUANCE...EXPECTED TO FALL BELOW HEAT ADVISORY CRITERIA. DRY AIR
IS EXPECTED TO FILTER INTO THE SOUTHWEST RESULTING IN THE HEAT
INDICES THERE TO BE AROUND 90...OR NEAR THE ACTUAL TEMPERATURE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 313 AM CDT THU JUL 18 2013
WE BEGIN THE LONG TERM PERIOD WITH A NORTHWEST UPPER FLOW PATTERN
AND ISOLATED TO SCATTERED THUNDERSTORM ACTIVITY ALONG THE
CONVERGENCE ZONE ASSOCIATED WITH A BACKDOOR COLD FRONT THAT PUSHES
SLOWLY WESTWARD FRIDAY AND SATURDAY. DEEP MOISTURE WILL BE LACKING
BUT THERE SHOULD BE ENOUGH MOISTURE/INSTABILITY ALONG THE BOUNDARY
FOR A FEW SHOWERS/THUNDERSTORMS EACH DAY. TEMPERATURES WILL BE
NOTICEABLY COOLER ACROSS THE SOUTH WITH READINGS FALLING INTO THE
80S AFTER A COUPLE DAYS OF 90 DEGREE HEAT.
THE REMAINDER OF THE EXTENDED PERIOD WILL BRING SEASONABLE
TEMPERATURES WITH PERIODIC THUNDERSTORM CHANCES ASSOCIATED WITH A
SERIES OF SHORTWAVES TRAVELING THROUGH A NORTHWEST FLOW ALOFT. THE
BETTER CHANCES AT THIS TIME APPEAR TO BE SUNDAY NIGHT INTO MONDAY
AND AGAIN TUESDAY NIGHT INTO WEDNESDAY. HOWEVER THIS FAR OUT TIMING
AND PLACEMENT OF INDIVIDUAL WAVES IS DIFFICULT AND A MODEL BLEND WAS
UTILIZED WHICH KEEPS AT LEAST A SLIGHT CHANCE OF CONVECTION THROUGH
THE PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 101 PM CDT THU JUL 18 2013
VFR CONDITIONS WILL PREVAIL OVER WESTERN AND CENTRAL NORTH
DAKOTA. THERE WILL BE A NARROW WINDOW WHERE THUNDERSTORMS COULD
IMPACT KJMS BETWEEN 20Z-22Z...AND IMPACT KMOT BETWEEN 01Z-03Z.
HOWEVER...GIVEN THE LOW CONFIDENCE IN OCCURRENCE...ONLY INDICATED
VCTS AND VFR CONDITIONS IN BOTH THE KMOT AND KJMS TAFS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR NDZ037-047-048-050-
051.
&&
$$
UPDATE...TM
SHORT TERM...NH
LONG TERM...TWH
AVIATION...TM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1027 AM CDT THU JUL 18 2013
.UPDATE...
ISSUED AT 1027 AM CDT THU JUL 18 2013
SOUTHWESTERLY FLOW ACROSS SOUTH CENTRAL AND SOUTHEASTERN NORTH
DAKOTA IS STILL FORECAST TO GENERATE HEAT INDICES APPROACHING 100F
OVER THE JAMES RIVER BASIN THIS AFTERNOON. AS A RESULT...WILL
MAINTAIN THE HEAT ADVISORY FOR THE JAMES RIVER BASIN THIS
AFTERNOON.
MSAS ANALYSIS SHOWS A SURFACE COLD FRONT EXTENDING FROM AROUND
MAYVILLE TO STEELE TO FORT YATES. LAPS ANALYSIS INDICATES
INCREASING SURFACE-BASED CAPE AROUND 1500 J/KG AHEAD OF THE COLD
FRONT OVER THE JAMES RIVER VALLEY. AS THE FRONT PUSHES ACROSS
NORTH DAKOTA TODAY...SHORT RANGE HIGH RES MODEL GUIDANCE PROGS
SCATTERED CONVECTION TO BEGIN OVER THE JAMES RIVER BASIN AROUND
20Z AND PUSH INTO THE SOUTHERN RED RIVER VALLEY THROUGH 00Z.
MARGINAL DEEP LAYER SHEAR IS THE ONLY INGREDIENT LIMITING
CONFIDENCE IN STORMS BECOMING SEVERE. AS A RESULT...WILL KEEP
SEVERE MENTION OUT OF THE ZONES...BUT KEEP IT IN THE HWO.
FARTHER NORTH...AN UPPER LEVEL WAVE IS EXPECTED TO TRIGGER
THUNDERSTORMS OVER THE SOUTHERN CANADIAN PRAIRIES LATER THIS
AFTERNOON. THE 3KM HRRR AND 00Z WRF PROG THIS ACTIVITY TO
PROPAGATE INTO NORTH CENTRAL NORTH DAKOTA AFTER 00Z THIS EVENING.
GIVEN THE STRONG UPPER FORCING AND POSSIBLE MCS
MAINTENANCE/PROPAGATION...NORTH CENTRAL NORTH DAKOTA COULD SEE
SEVERE STORMS BETWEEN 00Z-03Z TONIGHT. WILL CONTINUE TO MENTION
THIS POSSIBILITY IN THE HWO.
UPDATE ISSUED AT 648 AM CDT THU JUL 18 2013
ELEVATED CONVECTION THAT DEVELOPED OVERNIGHT IN FAR NORTHWEST
NORTH DAKOTA HAS MOVED EAST OUT OF THE FORECAST AREA. THEREFORE WE
HAVE REMOVED THE POPS ACROSS THE FAR NORTH CENTRAL FOR THIS
MORNING. OTHERWISE MINIMAL UPDATES THIS MORNING. DID REDUCE CLOUD
COVER A BIT ACROSS WITH THE EXITING PRECIPITATION AND RAISED IT A
BIT OVER THE SOUTHWEST AS MID LEVEL CLOUDS MOVE INTO THIS AREA
AHEAD OF A MID LEVEL SHORTWAVE. AS THE SHORTWAVE MOVES ACROSS THE
SOUTHERN PRAIRIE PROVINCES OF CANADA TODAY CONVECTION IS EXPECTED
TO DEVELOP ACROSS THE NORTHERN TIER COUNTIES LATE THIS AFTERNOON
AND POSSIBLY ALONG THE SURFACE TROUGH IN THE SOUTH CENTRAL BY
EARLY TO MID AFTERNOON. CURRENT FORECAST HAS THIS COVERED. NO
CHANGES TO THE CURRENT HEAT ADVISORY OVER THE JAMES RIVER VALLEY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 313 AM CDT THU JUL 18 2013
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE CHANCES FOR
THUNDERSTORMS NORTH AND SOUTH AND VERY WARM AND HUMID CONDITIONS
SOUTH CENTRAL AND SOUTHEAST.
CURRENTLY...ZONAL FLOW ALOFT WITH AN EMBEDDED S/WV MOVING EAST
ALONG THE INTERNATIONAL BORDER. ONGOING EARLY MORNING CONVECTION
FAR NORTH WILL START TO PUSH OFF TO THE NORTH AND EAST NOW THROUGH
12Z AS THE MID LEVEL ENERGY PUSHES EAST AND THE INFLUENCE OF A
NOCTURNAL LOW LEVEL JET DECREASES WITH TIME.
FOR THE REST OF THIS MORNING...AFTER THE EARLY MORNING CONVECTION
NORTH...WE LOOK TO BE MAINLY DRY UNTIL MID TO LATE MORNING WHEN
MODELS SUGGEST PRECIPITATION DEVELOPING OVER SOUTHEASTERN MONTANA
AND PERHAPS AS FAR EAST AS FAR SOUTHWEST NORTH DAKOTA AS AN
UPSLOPE FLOW MATERIALIZES.
SFC TROUGH AXIS THURSDAY AFTERNOON WILL BE ORIENTATED FROM THE
BLACK HILLS OF SOUTH DAKOTA NORTHEAST INTO THE CENTRAL RED RIVER
VALLEY OF EASTERN NORTH DAKOTA. WHILE MID LEVEL FORCING IS
EXPECTED TO BE WEAK OVER NORTH DAKOTA WITH NO REAL WAVE FEATURED
IN MODELS UNTIL LATER IN THE DAY ACROSS THE NORTH...MAY BE ENOUGH
LOW LEVEL FORCING/CONVERGENCE ALONG THE TROUGH AXIS TO GENERATE
DAYTIME THUNDERSTORMS OVER MY SOUTHERN COUNTIES WITH PLENTY OF
INSTABILITY EXPECTED TO BE IN PLACE.
CHANCES FOR THUNDERSTORMS INCREASE ACROSS THE NORTH AND DEVELOP
EAST AND SLIGHTLY SOUTH MID TO LATE AFTERNOON AS A MID LEVEL S/WV
TROUGH MOVES EAST-SOUTHEAST INTO SOUTHERN SASKATCHEWAN 21-00Z AND
INTO NORTHERN NORTH DAKOTA THURSDAY EVENING. COVERAGE AND CHANCES
FOR THUNDERSTORMS DECREASE AFTER 06Z WITH THE WAVE CONTINUING TO
TRACK SOUTHEAST TOWARDS/INTO WESTERN MINNESOTA. WILL CONTINUE TO
MENTION THE POSSIBILITY OF SEVERE THUNDERSTORMS IN THE HWO.
BESIDES THUNDERSTORM CHANCES TODAY...BOUNDARY LAYER TEMPERATURES
APPROACHING 30C ACROSS THE SOUTH WILL RESULT IN AFTERNOON
TEMPERATURES IN THE 90S ALONG AND SOUTH OF INTERSTATE 94...WITH
THE WARMEST TEMPERATURES FAR SOUTH CENTRAL AND SOUTH EAST WHERE
HIGHS ARE FORECAST TO CLIMB TO OVER 95F. COMBINED WITH SFC
DEWPOINTS 65-70F...HEAT INDICES WILL APPROACH 100F OVER THE JAMES
RIVER BASIN AND REACH INTO THE UPPER 90S FAR SOUTH CENTRAL. WILL
THUS MAINTAIN THE HEAT ADVISORY FOR THE JAMES RIVER BASIN FOR THIS
AFTERNOON WHERE THE HIGHEST HEAT INDEX IS EXPECTED...AND LEAVE
THE FAR SOUTH CENTRAL OUT FOR NOW AS THEY ARE...AT THIS FORECAST
ISSUANCE...EXPECTED TO FALL BELOW HEAT ADVISORY CRITERIA. DRY AIR
IS EXPECTED TO FILTER INTO THE SOUTHWEST RESULTING IN THE HEAT
INDICES THERE TO BE AROUND 90...OR NEAR THE ACTUAL TEMPERATURE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 313 AM CDT THU JUL 18 2013
WE BEGIN THE LONG TERM PERIOD WITH A NORTHWEST UPPER FLOW PATTERN
AND ISOLATED TO SCATTERED THUNDERSTORM ACTIVITY ALONG THE
CONVERGENCE ZONE ASSOCIATED WITH A BACKDOOR COLD FRONT THAT PUSHES
SLOWLY WESTWARD FRIDAY AND SATURDAY. DEEP MOISTURE WILL BE LACKING
BUT THERE SHOULD BE ENOUGH MOISTURE/INSTABILITY ALONG THE BOUNDARY
FOR A FEW SHOWERS/THUNDERSTORMS EACH DAY. TEMPERATURES WILL BE
NOTICEABLY COOLER ACROSS THE SOUTH WITH READINGS FALLING INTO THE
80S AFTER A COUPLE DAYS OF 90 DEGREE HEAT.
THE REMAINDER OF THE EXTENDED PERIOD WILL BRING SEASONABLE
TEMPERATURES WITH PERIODIC THUNDERSTORM CHANCES ASSOCIATED WITH A
SERIES OF SHORTWAVES TRAVELING THROUGH A NORTHWEST FLOW ALOFT. THE
BETTER CHANCES AT THIS TIME APPEAR TO BE SUNDAY NIGHT INTO MONDAY
AND AGAIN TUESDAY NIGHT INTO WEDNESDAY. HOWEVER THIS FAR OUT TIMING
AND PLACEMENT OF INDIVIDUAL WAVES IS DIFFICULT AND A MODEL BLEND WAS
UTILIZED WHICH KEEPS AT LEAST A SLIGHT CHANCE OF CONVECTION THROUGH
THE PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 648 AM CDT THU JUL 18 2013
VFR CONDITIONS ARE EXPECTED THROUGH THE 12Z TAF PERIOD. CHANCES
FOR MORNING THUNDERSTORMS WILL DECREASE 12-15Z NORTH AND WILL
LEAVE OUT ANY MENTION FOR KISN-KMOT. ANOTHER ROUND OF
THUNDERSTORMS WILL DEVELOP SOUTH EARLY TO MID AFTERNOON...AND
ACROSS THE NORTH MID TO LATE AFTERNOON INTO THIS EVENING. WILL
INCLUDE A VCTS/VCSH FOR KMOT AND KJMS WHERE THE BETTER CHANCES ARE
EXPECTED.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR NDZ037-047-048-050-
051.
&&
$$
UPDATE...TM
SHORT TERM...NH
LONG TERM...TWH
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
955 AM CDT THU JUL 18 2013
.UPDATE...
ISSUED AT 955 AM CDT THU JUL 18 2013
SHOWERS AND THUNDERSTORMS ASSOCIATED WITHIN STRONGER 850MB WARM
AIR ADVECTION WILL CONTINUE TO PROPAGATE TO THE EAST THIS
MORNING...EXITING THE FA WITHIN THE NEXT COUPLE HOURS. EXPECT A
BREAK IN ACTIVITY UNTIL SOMETIME LATER THIS AFTERNOON. 14Z LAPS
ANALYSIS INDICATES A VERY STRONG CAP AND THIS WILL NEED TO ERODE
BEFORE ANY REDEVELOPMENT. THUS...LOWERED POPS AND REMOVED WEATHER
TO INDICATE THIS POTENTIAL LULL.
FOR THIS AFTERNOON...THE SURFACE BOUNDARY (LOCATED ALONG A VALLEY
CITY TO GRAND FORKS TO BAUDETTE LINE) WILL MAKE LITTLE MOVEMENT
TO THE EAST UNTIL THIS EVENING WHEN THE MAIN UPPER WAVE FINALLY
BEGINS TO APPROACH NE ND. THIS WILL ALLOW AMPLE HEATING AND
MOISTURE RETURN TO THE EAST OF THIS FEATURE. MOST MODEL GUIDANCE
INDICATES MLCAPE AROUND 3000 J/KG ACROSS WEST CENTRAL MINNESOTA
(OR JUST AHEAD OF THE SURFACE BOUNDARY). DEEP LAYER SHEAR WILL BE
INCREASING INTO THE EVENING HOURS...WHICH SHOULD LEAD TO STRONGER
STORMS. THE MAIN QUESTIONS AT THIS POINT ARE WHEN/IF MLCIN WILL
LOWER ENOUGH FOR INITIATION...AND WHERE EXACTLY WILL THE SFC
BOUNDARY BE LOCATED. 12Z HRRR INDICATES INITIATION 21Z-00Z FROM SE
ND INTO THE BJI AREA...WITH MORE WIDESPREAD ACTIVITY EAST OF THE
VALLEY. FOLLOWED THIS IDEA FOR POPS...AND DID INCLUDE T+ FOR THE
BEMIDJI...DETROIT LAKES...PARK RAPIDS...AND WADENA AREAS (WHICH
THE 09Z SREF INDICATES HAVE THE BEST POTENTIAL FOR SEVERE).
THERE SHOULD BE ADDITIONAL ACTIVITY THIS EVENING AS THE MAIN UPPER
WAVE DROPS THROUGH THE FA. NOT SURE HOW MUCH INSTABILITY WILL BE
LEFT OVER FOR SEVERE POTENTIAL AND WILL MONITOR.
THE HEAT ADVISORY STILL LOOKS GOOD.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 330 AM CDT THU JUL 18 2013
THE MAIN CHALLENGE THIS MORNING WILL BE SEVERE POTENTIAL TODAY
INTO TONIGHT. MODELS ARE IN FAIRLY GOOD AGREEMENT...ALTHOUGH
DIFFER IN REGARDS TO TIMING/PLACEMENT OF SFC LOW THIS AFTERNOON.
THIS WILL BE IMPORTANT TO SEVERE WEATHER THREAT TODAY. THE GFS HAS
BEEN THE MOST CONSISTENT THOUGH SO WILL FOLLOW.
FOR TODAY...THERE WILL BE ONGOING ELEVATED THUNDERSTORMS THIS
MORNING MAINLY IN THE NORTHERN 1/3 OF THE REGION. A FEW STORMS
COULD BE STRONG TO LOCALLY SEVERE WITH PERHAPS SOME LARGE HAIL.
HEAVY RAINFALL IS ALSO EXPECTED NEAR ANY STORM WITH PWATS AROUND
1.8 INCHES. THERE SHOULD BE SOMEWHAT OF A BREAK IN CONVECTION FROM
LATE MORNING INTO EARLY AFTERNOON. EXPECT STORMS TO RAPIDLY
DEVELOP THIS AFTERNOON AT LEAST IN NW MN...WHERE MLCAPES WILL BE
AROUND 3000 J/KG WITH 0-6KM BULK SHEAR AROUND 45KT. THE INITIAL
STORM MODE SHOULD BE SUPERCELLS CAPABLE OF VERY LARGE
HAIL...DAMAGING WINDS AND AN ISOLATED TORNADO IS ALSO POSSIBLE.
THE BEST TORNADO POTENTIAL SHOULD OCCUR ALONG A ROS-PKD LINE AND
POINTS NORTH AND EAST FROM 20Z-00Z. FURTHER SOUTH...EXPECT A HOT
DAY WITH TEMPS INTO THE LOW/MID 90S AND HEAT INDICES NEAR OR
SLIGHTLY OVER 100. WILL ISSUE A HEAT ADVISORY HERE AND MOST OF THE
CONVECTION COULD BE CAPPED HERE WITH WARM TEMPS AT 850MB AROUND
+25C.
FOR TONIGHT...STORMS WILL LINGER WITH A STRONGER SHORTWAVE
DROPPING THROUGH DEVELOPING NW FLOW ALOFT. EXPECT A SEVERE THREAT
OF WIND/HAIL UNTIL AROUND 06Z...BEFORE ACTIVITY MOVES EAST OF THE
REGION.
ON FRIDAY...ANOTHER SHORTWAVE DROPS THROUGH THE REGION WITH
LINGERING INSTABILITY AND COLD AIR ALOFT. THERE SHOULD BE AT LEAST
A FEW SHOWERS AND STORMS POSSIBLE BY AFTERNOON IN MOST AREAS WITH
MUCH COOLER TEMPS.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 330 AM CDT THU JUL 18 2013
FOR SATURDAY...TEMPS WILL COOL INTO THE 70S FOR MOST AREAS AND
NEAR 70 IN THE FAR NORTH. THERE WILL BE A LOW CHANCE FOR A SHOWER
OR STORM IN THE FAR SOUTH MAINLY DURING THE AFTERNOON.
FOR SUNDAY TO WEDNESDAY... MODELS IN FAIR AGREEMENT WITH THE
EXTENDED TIME FRAME FOR THE FIRST HALF OF NEXT WEEK. PREDOMINATE
NW 500MB FLOW IS EXPECTED TO GIVE COOLER THAN MID JULY NORMAL
TEMPS FOR THE PERIOD. MONDAY WILL BE THE EXCEPTION AS WARM HUMID
AIR LIFTS INTO THE AREA AHEAD OF SHORT WAVE ENERGY. THIS WILL ALSO
SET THE STAGE FOR A FAIRLY GOOD CHANCE OF CONVECTION ACROSS THE
AREA. OTHERWISE SLIGHT CHC AND CHC POPS EXISTS IN NW FLOW AS TIMING
OF WEAK SW REMAINS POOR.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 645 AM CDT THU JUL 18 2013
HAVE MENTIONED SOME VCTS THIS MORNING AND AFTERNOON IN THE
NORTH...WITH THE SOUTH LIKELY REMAINING MOSTLY DRY. EASTERLY WINDS
SHOULD SHIFT MORE WESTERLY BY THIS EVENING FROM WEST TO EAST
BEHIND A COLD FRONT. MOSTLY VFR CIGS EXPECTED EXCEPT NEAR SHOWERS
AND STORMS WHERE MVFR CONDITIONS ARE POSSIBLE. THERE IS A PATCH OF
IFR CIGS NEAR DVL...AND EXPECT THIS TO DISSIPATE WITHIN THE NEXT
FEW HOURS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM CDT THIS EVENING
FOR NDZ038-039-049-052-053.
MN...HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM CDT THIS EVENING
FOR MNZ003-027>031-040.
&&
$$
UPDATE...TG
SHORT TERM...DK
LONG TERM...JK/DK
AVIATION...DK
AREA FORECAST DISCUSSION
NWS TULSA OK
1237 PM CDT THU JUL 18 2013
.DISCUSSION...
ELEVATED HEATING ON THE HIGHER TERRAIN HAS ONCE AGAIN SET OFF SOME
ISOLATED TO WIDELY SCATTERED SHOWERS AS OF 1230 PM. THE LATEST
DATA FROM THE HRRR SUGGESTS THAT THESE AFTERNOON POPCORN SHOWERS
AND STORMS COULD ENCOMPASS MUCH OF EASTERN OKLAHOMA AND NORTHWEST
ARKANSAS BY LATER IN THE AFTERNOON. SLIGHT CHANCE POPS HAVE BEEN
EXPANDED NORTH AND WEST SOME...TO INCLUDE MOST AREAS EAST OF
HIGHWAY 75. UPDATED PRODUCTS HAVE BEEN SENT.
LACY
&&
.PREV DISCUSSION... /ISSUED 1218 PM CDT THU JUL 18 2013/
DISCUSSION...
THE 18Z TAF DISCUSSION IS INCLUDED BELOW.
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
VFR CONDITIONS WILL PREVAIL FOR THE NEXT 24 HOURS. SMALL CHANCES
FOR A TSTM OVR SE OK/W CNTRL AR COULD AFFECT KMLC AND KFSM TAFS.
WILL LEAVE OUT MENTION FOR NOW...AN AMEND MAY BE NEEDED LATER. AFTER
SOME DENSE FOG AT KFYV 2 NIGHTS AGO...THERE WAS NO MORNING FOG
THIS MORNING. THEREFORE...WILL NOT INCLUDE A MENTION OF FOG IN
THIS SET OF TAFS AS THE GUIDANCE WOULD SUGGEST.
LACY
PREV DISCUSSION... /ISSUED 552 AM CDT THU JUL 18 2013/
DISCUSSION...
VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD...THOUGH AT LEAST
BRIEF MVFR VISIBILITY REMAINS POSSIBLE AT KFYV/KBVO EARLY THIS
MORNING. ISOLATED THUNDERSTORMS POSSIBLE OVER FAR SE OKLAHOMA AND
WESTERN WITH IMPACTS BRIEF AND VERY LOCALIZED.
PREV DISCUSSION... /ISSUED 330 AM CDT THU JUL 18 2013/
DISCUSSION...
FAIRLY TYPICAL SUMMER WEATHER ANTICIPATED FOR MUCH OF THE FORECAST
PERIOD...WITH OUR AREA REMAINING UNDER UPPER RIDGING CONDITIONS.
SHORT RANGE GUIDANCE SUGGESTS SOME WEAKNESS IN THE UPPER RIDGE TODAY
AND FRIDAY...AND WILL CONTINUE WITH AFTERNOON LOW POPS MAINLY FOR
PARTS OF SE OK/NW AR. HIGHS EXPECTED TO BE IN THE 90S AREAWIDE...AND
CURRENT DEWPOINT FORECAST WILL KEEP HEAT INDEX VALUES BELOW ADVISORY
CRITERIA.
A WEAK FRONTAL BOUNDARY IS EXPECTED TO DROP INTO KS AND MO OVER THE
WEEKEND...ALTHOUGH IT LOOKS TO REMAIN JUST TO OUR NORTH. HAVE KEPT
SLIGHTLY HIGHER POPS ACROSS FAR NE OK/NW AR...NEAREST THE
BOUNDARY...FOR BOTH SATURDAY AND SUNDAY.
NWLY FLOW ALOFT WILL DEVELOP ACROSS THE CNTRL PLAINS SUNDAY AND INTO
EARLY NEXT WEEK...WITH OUR AREA REMAINING JUST ALONG THE SRN EDGE OF
THE STRONGER FLOW. THIS PATTERN SUGGESTS THAT THE BULK OF CONVECTION
SHOULD REMAIN TO OUR NORTH...BUT WILL NEED KEEP AN EYE ON MCS
ACTIVITY POTENTIALLY GRAZING SOME OF OUR AREA. STRONGER LOW-LEVEL
SWLY FLOW WILL SUPPORT A SLIGHT WARMUP...WITH AFTERNOON TEMPS
PUSHING THE UPPER 90S TO NEAR 100 ACROSS PARTS OF ERN OK GOING INTO
MID-WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 96 74 96 75 / 10 10 10 10
FSM 96 74 97 74 / 20 10 20 10
MLC 94 71 95 72 / 20 10 10 10
BVO 96 68 96 72 / 10 0 10 10
FYV 93 68 92 70 / 20 10 20 10
BYV 91 69 93 71 / 20 10 20 10
MKO 95 71 96 73 / 20 10 10 10
MIO 97 72 96 74 / 10 10 10 10
F10 94 72 95 73 / 10 10 10 10
HHW 94 73 96 73 / 20 10 20 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...30
AREA FORECAST DISCUSSION
NWS SPOKANE WA
420 AM PDT Thu Jul 18 2013
.SYNOPSIS...
A prolonged period of dry weather is expected over the Inland
Northwest. No precipitation is anticipated for at least the next
seven days. Temperatures will be seasonably warm this weekend into
next week.
&&
.DISCUSSION...
Thursday through Friday night: A low amplitude ridge of high
pressure will be over the Inland NW to end the work week promoting
mostly clear skies and above normal warmth. Temperatures in
general will be warming into the 90`s for most valleys with light,
terrain driven winds. A broad upper-level low extending west from
central Canada will prevent the jet stream from migrating much
further north then the WA/BC border. This will keep a pool of
instability over southern BC...and perhaps into the extreme
northern mountains of WA. The threat is low but does exist and NAM
continues to indicate enough surface based instability over the
Pasayten Wilderness with the 00z model suite to support a stray
thunderstorm. Given its bias for placing instability over this
area...we have kept thunder mention out of the forecast but will
do another analysis in the morning to see how models and HRRR are
handling the boundary layer moisture with the idea that we may
need to include an isolated threat. /sb
Saturday through Monday: The biggest change to the forecast for
the weekend was to lower temperatures a few degrees. A couple of
days ago, the medium range models were suggesting a stronger upper
ridge for Saturday and Sunday. They have now trended toward a
flatter 500mb flow pattern. Afternoon temperatures Saturday
through Monday will still be above average, but not as hot as
previously thought. The air mass will be exceedingly dry. Model
cross sections for the weekend into Monday show very little chance
for clouds. The dry westerly flow Saturday and Sunday will likely
cause surface dewpoints to plunge into the 20s and low 30s. Some
of the driest air we have experienced this summer. The warm and
dry conditions will continue to cure the fuels in the higher
elevations bringing our region into the heart of the wildfire
season. /GKoch
Tuesday through Thursday: Models seem to initialize this period
rather well with a low pressure system off of the northern BC
coast and zonal flow coming around the low and into our region.
With the low having a cooler source region for moisture models
are not showing any significant chance of precipitation at this
time. The feature to watch will be the movement of the mentioned
low over the latter part of the week. The Euro and GEM both have
it moving towards land that would allow for increased winds
earlier whereas the GFS holds off on that movement and slowly
moves it down the BC coast which would bring winds to our
region...but at a later time. Depending on the track will also
determine if precip chances need updated with the associated
moisture and cold pool interactions that would likely take place.
This low will be an important feature to keep an eye on as it
could play a large role in the winds and precip chances for our
area. Stronger winds coupled with the forecasted low RH values
could lead to fire weather concerns and potentially highlights.
With this being in the far extended I leaned toward the more
consistent model in the GFS that would promote the zonal flow for
a longer period. Temperatures look to hold steady in the mid 80s
and low 90s for most making for pleasant conditions in the middle
part of next week. /Fliehman
&&
.AVIATION...
12Z TAFS: VFR conditions are expected through 12z Friday. A few
cumulus buildups are possible along the immediate Canadian border
...otherwise skies are expected to remain generally clear with light
terrain driven winds. /sb
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 89 60 92 62 91 59 / 0 0 0 0 0 0
Coeur d`Alene 90 55 91 57 90 56 / 0 0 0 0 0 0
Pullman 88 47 90 49 90 51 / 0 0 0 0 0 0
Lewiston 95 61 98 63 97 63 / 0 0 0 0 0 0
Colville 92 54 93 56 94 55 / 0 0 0 0 0 0
Sandpoint 87 50 88 52 89 51 / 0 0 0 0 0 0
Kellogg 87 55 90 57 89 56 / 0 0 0 0 0 0
Moses Lake 94 57 97 59 97 60 / 0 0 0 0 0 0
Wenatchee 93 65 95 67 95 62 / 0 0 0 0 0 0
Omak 94 55 97 57 96 59 / 0 0 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$