Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/18/15
AREA FORECAST DISCUSSION
NWS TUCSON AZ
420 AM MST SUN AUG 16 2015
.SYNOPSIS...EXPECT VERY HOT TEMPERATURES AGAIN TODAY THEN DAYTIME
TEMPERATURES WILL MODERATE SEVERAL DEGREES DURING THE MIDDLE AND
LATTER PART OF THIS WEEK. THERE IS ENOUGH MOISTURE FOR A CHANCE OF
THUNDERSTORMS THROUGH TONIGHT. LESS THUNDERSTORM ACTIVITY WILL THEN
OCCUR MONDAY FOLLOWED BY DRY CONDITIONS TUESDAY AND WEDNESDAY. A
SLIGHT CHANCE OF THUNDERSTORMS WILL RETURN BY THE END OF THE WEEK.
&&
.DISCUSSION...KEMX WSR-88D DEPICTED SCATTERED 35-55 DBZ ECHOES
GENERALLY FROM THE TUCSON METRO AREA WWD ACROSS THE TOHONO
O`ODHAM...AND SWD ACROSS ERN SANTA CRUZ/SWRN COCHISE COUNTIES AT
11Z. MOST RAIN AMOUNTS AT LOWER ELEVATIONS SINCE LAST EVENING HAVE
BEEN LESS THAN ONE TENTH OF AN INCH. HOWEVER...A FEW GAUGES ON THE
CATALINA MOUNTAINS NE OF TUCSON HAVE RECORDED BETWEEN ONE HALF OF AN
INCH AND ONE INCH OF RAINFALL.
THE 16/06Z UNIV OF AZ WRF-NAM AND THE 16/10Z HRRR DEPICT THAT THE
BULK OF THESE SHOWERS/TSTMS WILL END AROUND 14Z-16Z. SHOWERS/TSTMS
ARE THEN EXPECTED TO DEVELOP ACROSS THE WHITE MOUNTAINS BY EARLY
THIS AFTERNOON. SHOWERS/TSTMS ARE THEN PROGGED TO MOVE SWWD MAINLY
ACROSS ERN SECTIONS OF THIS FORECAST AREA THIS AFTERNOON AND
EVENING. THUS...HAVE CONTINUED WITH ISOLATED TO SCATTERED SHOWERS/
TSTMS THIS AFTERNOON/EVENING GENERALLY FROM TUCSON EWD TO THE NEW
MEXICO BORDER. HAVE OPTED TO MAINTAIN A SLIGHT CHANCE OF SHOWERS/
TSTMS LATE TONIGHT INTO EARLY MON MORNING ACROSS MUCH OF SE ARIZONA.
IF THE 16/06Z UNIV OF AZ WRF-NAM IS REALITY...AM SOMEWHAT CONCERNED
ABOUT THE PROSPECT FOR POTENTIALLY STRONG THUNDERSTORMS TO OCCUR
BEGINNING AROUND MIDNIGHT TONIGHT ACROSS ERN PIMA COUNTY...INCLUDING
THE TUCSON METRO AREA...AND CONTINUING INTO DAYBREAK MON.
16/00Z NAM/GFS/ECMWF/CMC REMAINED CONSISTENT WITH PREVIOUS SOLUTIONS
IN DEPICTING HIGH PRESSURE ALOFT TO BECOME CENTERED OVER SRN
CALIFORNIA MON AS A SHORTWAVE TROUGH MOVES EWD ACROSS THE
NRN/CENTRAL ROCKIES. A DRYING TREND SHOULD COMMENCE MON AS THE FLOW
ALOFT BECOMES INCREASINGLY NWLY. HAVE MAINTAINED ISOLATED TO
SCATTERED SHOWERS/TSTMS FROM TUCSON EWD/SWD MON AND MON EVENING WITH
DRY CONDITIONS ELSEWHERE. PRECIP-FREE CONDITIONS ARE FORECAST TO
OCCUR AREA-WIDE TUE-WED IN RESPONSE TO NWLY FLOW ALOFT WITH HIGH
PRESSURE REMAINING CENTERED NEAR THE SRN CALIFORNIA COAST.
A SIMILAR SCENARIO EXISTS THUR AS THE UPPER FLOW BECOMES MORE WLY.
HOWEVER...SLIGHTLY INCREASED LOWER-LEVEL MOISTURE JUSTIFIES A SLIGHT
CHANCE OF SHOWERS/TSTMS THUR AFTERNOON/EVENING SOUTH-TO-SOUTHEAST OF
TUCSON. THEREAFTER...THE GFS WAS SOMEWHAT MORE ROBUST VERSUS THE
ECMWF WITH THE PROSPECT FOR SHOWERS/TSTMS FRI-SAT. THERE APPEARS TO
BE ENOUGH MOISTURE TO MAINTAIN A SLIGHT CHANCE OF SHOWERS/TSTMS FROM
TUCSON EAST TO THE NEW MEXICO BORDER FRI-SAT. PRECIP-FREE CONDITIONS
SHOULD CONTINUE FRI-SAT ACROSS WRN PIMA COUNTY.
THE EXCESSIVE HEAT WARNING REMAINS IN EFFECT FROM NOON TODAY TO 8 PM
MST THIS EVENING FOR MUCH OF PIMA COUNTY...INCLUDING THE TUCSON
METRO AREA...AND FOR SOUTH CENTRAL PINAL COUNTY. DAYTIME TEMPS WILL
THEN MODERATE AN AVERAGE OF 3 DEGS F OR SO MON-TUE FOLLOWED BY NO
SIGNIFICANT CHANGE IN HIGH TEMPS WED. THEREAFTER...A DEGREE-OR-TWO
OF ADDITIONAL DAILY COOLING IS ON TAP THUR-SAT.
&&
.AVIATION...VALID THRU 17/12Z.
EXPECT ISOLATED TO SCATTERED -TSRA/-SHRA INTO EARLY MONDAY MORNING.
BRIEF WIND GUSTS OF 35-45 KTS MAY OCCUR WITH THE STRONGER TSRA.
OTHERWISE...CLOUD DECKS WILL GENERALLY BE ABOVE 10K FT AGL AND
SURFACE WIND WILL BE LESS THAN 10 KTS INTO EARLY MONDAY MORNING.
AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...THERE IS A CHANCE OF SHOWERS AND THUNDERSTORMS
THROUGH TONIGHT...WITH THE BULK OF THIS ACTIVITY EXPECTED TO BE EAST
OF TUCSON THIS AFTERNOON AND EVENING. LESS COVERAGE OF THUNDERSTORMS
WILL THEN OCCUR MONDAY FOLLOWED BY DRY CONDITIONS AREA-WIDE TUESDAY
AND WEDNESDAY. A SLIGHT CHANCE OF THUNDERSTORMS WILL RETURN MAINLY
FROM TUCSON EAST AND SOUTH BY FRIDAY AND CONTINUING INTO SATURDAY.
OUTSIDE OF THUNDERSTORM WIND GUSTS...20-FT WINDS WILL GENERALLY BE
LESS THAN 15 MPH DURING THE NEXT SEVERAL DAYS. VERY HOT TEMPERATURES
WILL OCCUR TODAY...THEN A SLOW MODERATION IN DAYTIME TEMPERATURES
WILL PREVAIL MONDAY THROUGH SATURDAY.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
EXCESSIVE HEAT WARNING FROM NOON TODAY TO 8 PM MST THIS EVENING
FOR AZZ501-502-504-505.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
FRANCIS
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND JUNCTION CO
847 PM MDT MON AUG 17 2015
.UPDATE...
ISSUED AT 847 PM MDT MON AUG 17 2015
FRONT IS PASSING THROUGH NORTHWEST COLORADO THIS EVENING. WITH
NEW FIRE STARTS AND GUSTS WITH THE FROPA NEAR 25 MPH WITH THE WIND
SHIFT HAVE EXTENDED THE RED FLAG WARNING. HUMIDITY IS ALSO SLOW TO
RECOVERY WITH THE PUNCH OF DRY AIR MOVING IN WITH THE FRONT.
ISOLATED CONVECTION POSSIBLE NEAR THE FRONT BUT THE MORE ENERGETIC
ARE APPEARS TO BE ASSOCIATED WITH A JET MAX MOVING INTO WEST
CENTRAL COLORADO THIS EVENING. EXPECT THIS AREA SOUTH OF I-70 TO
CONTINUE WILL INTO THE LATE EVENING HOURS BEFORE THE LEFT EXIT
REGION OF THIS JET SLIPS SOUTHEAST.
&&
.SHORT TERM...(TONIGHT THROUGH TUESDAY NIGHT)
ISSUED AT 327 PM MDT MON AUG 17 2015
COMBINATION OF JET MAXIMA ALOFT AND CONDITIONALLY UNSTABLE
ENVIRONMENT HAS GENERATED SCATTERED STORMS THIS AFTERNOON...PRIMARILY
SOUTH OF US HIGHWAY 40. GIVEN THE SHEAR ENVIRONMENT...SOME CELLS
WILL BE STRONG WITH GUSTY WINDS AND SMALL HAIL. STORM PREDICTION
CENTER PLACED THE ERN FRINGE OF OUR FORECAST AREA IN THE MARGINAL
CATEGORY. CURRENT TRENDS OFFERED BY RADAR AND 1 MIN SATELLITE
IMAGES (FORTUNATE THAT IT EXTENDS OVER THE WESTERN SLOPE TODAY)
SHOW STRENGTHENING STORMS NEAR THE I70 CORRIDOR. WEATHER SPOTTER
BETWEEN GLENWOOD SPRINGS AND CARBONDALE REPORTED ONE HALF INCH
SIZED HAIL. WITH UPSTREAM TROUGH OVER THE NRN ROCKIES APPROACHING
THE CENTRAL ROCKIES...NOT UNREASONABLE THAT STRONGER STORMS
(PERHAPS A SEVERE STORM OR TWO) MAY FORM LATE THIS AFTERNOON. BY
NIGHTFALL...STORMS SHOULD BE DIMINISHING. EXCEPT TRAILING ENERGY
OVER SOUTHWEST COLORADO MAY KEEP THINGS ACTIVE OVER LA PLATA AND
ARCHULETA COUNTY UNTIL MIDNIGHT OR SO.
NORTHEAST UTAH/EXTREME NW COLORADO...DEEP MIXED LAYER ASSOCIATED
WITH THE SURFACE TROUGH RESULTS IN RAPID DRYING. STORMS WILL NOT
BE FAVORED IN THIS REGION AS THE MOIST ENVIRONMENT GETS PUSHED
EASTWARD BY UPSTREAM TROUGH.
TUESDAY AND TUESDAY NIGHT...
COOLER AND MUCH DRIER AIR UNDER NW FLOW OVER THE AREA TUESDAY AND
TUESDAY NIGHT SHOULD RESULT IN MAX TEMPERATURES 5-10 DEGREES F
LOWER THAN TODAY...WITH GREATEST COOLING IN NORTHERN AND CENTRAL
ZONES. ALL MODELS SHOW H7 TEMPERATURES DROPPING 4 TO 8 DEGREES C
LOWER THAN TODAY. MIN TEMPERATURES TUESDAY NIGHT COULD DROP INTO
THE UPPER 30S IN SOME OF THE COLDER HIGH ELEVATION VALLEYS SUCH AS
IN THE GUNNISON AREA. MOSTLY CLEAR SKIES EXPECTED OVER THE AREA...
WITH SOME CLOUD BUILDUPS IN THE AFTERNOON AND EARLY EVENING OVER
THE MOUNTAINS AND ONLY ISOLATED THUNDERSTORMS MAINLY NEAR THE
CONTINENTAL DIVIDE AROUND PEAK HEATING TIME.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 327 PM MDT MON AUG 17 2015
WEDNESDAY THROUGH THURSDAY NIGHT...
DRY NORTHWEST FLOW CONTINUING WEDNESDAY THROUGH THURSDAY NIGHT
...WITH MOSTLY CLEAR SKIES EXPECTED TO PERSIST. MODELS DROPPING
H7 TEMPERATURES ANOTHER COUPLE DEGREES C ON WEDNESDAY WITH MAX
TEMPERATURES GENERALLY 3 DEGREES F LOWER THAN TUESDAY. THEN AS
UPPER TROUGH/LOW TRAVERSING NORTHERN STATES SHIFTS EASTWARD ON
THURSDAY...EXPECT SOME AIRMASS WARMING WITH MAX TEMPERATURES
SEVERAL DEGREES WARMER THURSDAY THAN ON WEDNESDAY.
FRIDAY THROUGH MONDAY...
MODELS INDICATE ANOTHER UPPER TROUGH BRUSHING OUR CWA BEGINNING
FRIDAY AND THEN MOVING TO THE EAST OF OUR AREA SATURDAY NIGHT.
EXPECT AN UPTICK OF MOISTURE INTO OUR AREA DURING THIS PERIOD
...THEN DECREASING SOME SUNDAY AND MONDAY UNDER A VERY WEAK
WESTERLY FLOW ALOFT WITH RESIDUAL MOISTURE UNDER THE INFLUENCE OF
DAYTIME HEATING. AFTER ANOTHER UNSEASONABLY WARM DAY ON FRIDAY...
NOTICEABLY COOLER AIR EXPECTED INTO OUR AREA AGAIN SATURDAY
THROUGH SUNDAY...BEFORE WARMER AIR RETURNS ON MONDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 327 PM MDT MON AUG 17 2015
SCATTERED -TSRA CONTINUE OVER THE CENTRAL ZONES SOUTH OF THE
/ROAN/FLAT TOP MOUNTAINS. KRIL KASE KEGE COULD SEE CIGS BLO 070
ALONG WITH SMALL HAIL AND ERRATIC WIND GUSTS OF 25-40KTS. AFT 03Z
STORMS BECOME ISOLATED IN COVERAGE WITH ALL STORMS ENDING BY 08Z.
VFR CONDITIONS CONTINUE THROUGH TUESDAY WITH ISOLATED AFTERNOON
-TSRA NEAR THE CONTINENTAL DIVIDE.
&&
.FIRE WEATHER...
ISSUED AT 1145 AM MDT MON AUG 17 2015
DEEP MIXED LAYER WILL RESULT THIS AFTERNOON AS LOWER SURFACE
PRESSURE OVER NW COLORADO DEEPENS. SUSTAINED WINDS OF 15-20 MPH
IS EXPECTED WITH PEAK GUSTS OF 35 MPH IN ADVANCE OF A COLD FRONT.
HIGHER RESOLUTION MODELS INDICATE THAT DEW POINT VALUES WILL DROP
QUICKLY WHEN THE SURFACE WINDS DEVELOP...THIS TREND MAY BE
VERIFYING AS THE KCAG (CRAIG) ASOS OBSERVED THE DEW POINT FALLING
FROM 48F TO 28F WITHIN TWO HOURS. THE HRRR MODEL SHOW VALUES
FALLING INTO THE 20S ACROSS MOFFAT COUNTY (FIRE WEATHER ZONE
200)...WHICH IS BELOW MOS GUIDANCE VALUES. SPLIT THE DIFFERENCE
BETWEEN THE HRRR AND GUIDANCE...THE NET RESULT IS HUMIDITY VALUES
OF 10-15% AFTER 20Z (2 PM). THE WINDS MAY PERSIST THROUGH THE
EARLY EVENING HOURS GIVEN TIGHTENING PRESSURE GRADIENTS. CRITICAL
FIRE WEATHER CONDITIONS MAY PERSIST UNTIL AFTER SUNSET.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...RED FLAG WARNING UNTIL MIDNIGHT MDT TONIGHT FOR COZ200-202.
UT...NONE.
&&
$$
UPDATE...15
SHORT TERM...PF/JRP
LONG TERM...JRP
AVIATION...JOE
FIRE WEATHER...PF
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
819 PM MDT MON AUG 17 2015
.UPDATE...
ISSUED AT 809 PM MDT MON AUG 17 2015
MOST TSTM ACTIVITY HAS ENDED OVER THE PLAINS EXCEPT FOR THE FAR
NERN CORNER. MEANWHILE ACTIVITY IS BEGINNING TO INCREASE OVER
LARIMER AND JACKSON COUNTIES. QG FIELDS STILL SHOW SOME MID LVL
ASCENT THRU 09Z AND COMBINED WITH ELY LOW LVL FLOW MAY SEE
ADDITONAL DEVELOPMENT OF SHOWERS/TSTMS ACROSS PORTIONS OF THE
PLAINS OVERNIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 227 PM MDT MON AUG 17 2015
MAIN CONCERN STILL REMAINS SEVERE WEATHER POTENTIAL ACROSS EASTERN
COLORADO THROUGH THIS EVENING. LATEST ACARS AIRCRAFT SOUNDINGS
STILL SHOWING SUBSTANTIAL CAP WITH STRONG INVERSION AROUND 700MB.
THE AIRMASS IS EVEN MORE COOLER AND STABLE OVER THE FAR NE CORNER
WITH TEMPERATURES ONLY IN THE 60S. THERE ARE SOME SCATTERED STORMS
MOVING RAPIDLY EAST OVER THE MOUNTAINS BUT MOST OF THIS ACTIVITY
EXPECTED TO DIMINISH AS IT ENTERS THE MORE HOSTILE AIRMASS. STILL
COULD SEE SOME OUTFLOW BOUNDARIES THAT PUSH INTO THE MORE UNSTABLE
ENVIRONMENT ACROSS THE PALMER DIVIDE. THIS AREA HAS HAD THE MOST
HEATING TODAY WITH READINGS IN THE LOWER TO MID 80S AND LOW 60S
DEWPOINTS. SURFACE BASED CAPES FROM 2000-3000J/KG IN THIS AREA.
EXPECT LARGE HAIL AND DAMAGING WINDS AND CAN`T RULE OUT A TORNADO
WITH SOUTHEAST LOW LEVEL FLOW.
AS THE EVENING GOES ON LOOKS LIKE THE BEST ACTIVITY WILL REFOCUS
FURTHER NORTH NEAR THE WYOMING AND NEBRASKA BORDER AREAS WITH
APPROACH OF STRONG UPPER LEVEL TROF. QG FIELDS SHOWING MODERATE QG
ASCENT OVER THE NE CORNER OVERNIGHT BEFORE TROF SWEEPS THROUGH
TUESDAY MORNING. WILL KEEP HIGHEST POPS OVERNIGHT OVER THE FAR NE
CORNER. A DRIER AIRMASS WILL SEEP INTO NORTHERN COLORADO TUESDAY
MORNING WITH SUBSIDENCE AND INCREASING GUSTY NORTHWEST WINDS.
THERE COULD STILL BE SOME LINGERING SHOWERS OVER THE FAR NE CORNER
TUESDAY MORNING. TUESDAY AFTERNOON WILL BE MAINLY DRY BUT SOME
LIGHT SHOWERS WILL DEVELOP OVER HIGHER EAST SLOPES BY LATER
AFTERNOON IN ADVANCE OF UPPER JET DIVING SOUTHWARD INTO COLORADO
BY TUESDAY EVENING.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 227 PM MDT MON AUG 17 2015
A STRONG UPPER LEVEL STORM SYSTEM WILL MOVE ACROSS THE UPPER MIDWEST
TUESDAY NIGHT...WITH AN UPPER LEVEL RIDGE OF HIGH PRESSURE JUST OFF
THE SOUTHERN COAST OF CALIFORNIA. A STRONG UPPER LEVEL JET MAX FOR
THIS TIME OF YEAR (90+KT) WILL BE NOSING INTO NORTH CENTRAL
COLORADO. BOTH THE NAM AND GFS ARE SHOWING SOME QG LIFT...AND
PRECIPITATION ASSOCIATED WITH THE JET. THE MODELS ARE ALSO SHOWING
SOME WEAK UPSLOPE FLOW AS WELL. THEREFORE...HAVE INCREASED POPS
ESPECIALLY FOR AREAS EAST OF THE MOUNTAINS AND NORTH OF I-70
TUESDAY EVENING AND WEDNESDAY MORNING. SOUNDINGS SHOW LITTLE OR NO
CAPE...THEREFORE THUNDERSTORMS ARE NOT EXPECTED. TEMPERATURES WILL
REMAIN ON THE COOL SIDE ON WEDNESDAY WITH HIGH TEMPERATURES IN THE
LOW TO MID 70S ON THE PLAINS.
WARMER AND DRIER WEATHER WILL RETURN TO NORTH CENTRAL AND
NORTHEASTERN COLORADO ON THURSDAY AS A DRIER WESTERLY FLOW ALOFT
SETS UP OVER COLORADO. ON FRIDAY...MODELS SHOW AN UPPER LEVEL TROUGH
OF LOW PRESSURE MOVING INTO THE NORTHERN GREAT BASIN...WITH A
MONSOONAL FLOW TRYING TO REESTABLISH OVER THE SOUTHWESTERN STATES.
THIS PATTERN MAY RESULT IN A FEW THUNDERSTORMS RETURNING TO THE
MOUNTAINS...ESPECIALLY SOUTH OF INTERSTATE 70. ON SATURDAY...THE
MODELS SHOW AN UPPER TROUGH MOVING OVER THE NORTHERN AND CENTRAL
ROCKIES...WITH AN ASSOCIATED 70+KT UPPER LEVEL JET MAX NOSING INTO
NORTHWESTERN COLORADO AND SOME ASSOCIATED QG LIFT.
ALL OF THESE FACTORS POINT TO A POSSIBLE ACTIVE WEATHER
DAY...HOWEVER...THE ONE NEGATIVE IS THAT LOW LEVEL MOISTURE SEEMS
TO LACKING WITH THIS SYSTEM. IF THIS SCENARIO PANS OUT...WE
PROBABLY COULD SEE ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
OVER THE AREA...MORE NUMEROUS OVER NORTHERN SECTIONS OF OUR CWA.
THE LACK OF MOISTURE WOULD LIMIT THE STRENGTH OF THE STORMS...BUT
IF ADDITIONAL MOISTURE WOULD WORK ITS WAY INTO AREA...SOME OF THE
STORMS COULD BE STRONG.
ANOTHER THING TO NOTE IS THAT THERE ARE SOME TIMING ISSUES BETWEEN
THE MODELS...WITH THE ECMWF BEING FASTER WITH THE TROUGH AND
ASSOCIATED FRONTAL PASSAGE. THE RESULT OF THIS IS THAT THE GFS
HAS A 700 MB TEMP AT SUN 00Z OF 16 DEGREES C AT DENVER...WHILE THE
ECMWF IS AROUND 8 DEGREES C.
THE UPPER TROUGH IS EXPECTED TO MOVE INTO THE CENTRAL PLAINS STATES
ON SUNDAY...WHICH SHOULD RESULT IN COOLER AND DRIER WEATHER ACROSS
THE CWA. DRY AND WARMER WEATHER IS EXPECTED EARLY NEXT WEEK AS UPPER
LEVEL HIGH PRESSURE BUILDS OVER THE ROCKY MOUNTAIN REGION.
&&
.AVIATION...(FOR THE TAFS THROUGH 06Z TUESDAY EVENING)
ISSUED AT 809 PM MDT MON AUG 17 2015
WILL HAVE TO WATCH STORMS OVER LARIMER COUNTY THE NEXT FEW HOURS
TO SEE IF THEY TURN MORE SE. HRRR HAS A LINE OF STORMS MOVING SE
ACROSS THE PLAINS BETWEEN 06Z AND 09Z WHICH COULD CLIP DIA. FOR
NOW WILL JUST MENTION VCTS AT DIA UNTIL IT BECOMES MORE OBVIOUS
HOW THINGS MAY EVOLVE. WINDS SHOULD BECOME MORE SLY BY MIDNIGHT
AND THEN SHIFT TO THE NORTH BY 09Z AS CDFNT MOVES ACROSS. WILL
KEEP IN STRATUS FOR THE 11Z-14Z TIMEFRAME.
&&
.HYDROLOGY...
ISSUED AT 227 PM MDT MON AUG 17 2015
CERTAINLY HEAVY RAIN WITH STORMS BUT STORM MOTIONS MOVING RATHER
QUICKLY AT THIS TIME SO OVERALL FLASH FLOOD THREAT IS LOW. FURTHER
SOUTH OVER CWA...FLOW IS WEAKER SO STORMS MAY BE MORE SLOW MOVING
ACROSS ELBERT AND LINCOLN COUNTIES WITH RAINFALL RATES UP TO 1
INCH IN 30 MINUTES OR LESS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...RPK
SHORT TERM...ENTREKIN
LONG TERM...KALINA
AVIATION...RPK
HYDROLOGY...ENTREKIN
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
1010 AM EDT SUN AUG 16 2015
.DISCUSSION...
TODAY...THE MORNING CAPE SOUNDING SHOWS DEEP S/SE FLOW OVER THE
AREA...AND VERY MOIST AIRMASS WITH 2.11 INCHES PRECIP WATER. A LARGE
AREA OF CONVECTION OFFSHORE BREVARD COUNTY HAS PUSHED ONSHORE WITH
SOME LIGHTNING STRIKES EVEN ON LAND. THIS IS UNUSUAL SO EARLY IN THE
MORNING AND INDICATES SOME SUPPORT ALOFT. INDEED...A LITTLE
INVESTIGATION REVEALS VORT ENERGY IN THE 900-700MB LAYER LIFTING
NORTH ACROSS THE AREA THIS MORNING SHOWN BY RAP ANALYSIS. THE FOCUS
FOR SHOWERS/STORMS WILL BE OVER THE COASTAL COUNTIES INITIALLY
SHIFTING TO THE INTERIOR THIS AFTN. THE SEA BREEZE WILL PUSH FAIRLY
RAPIDLY INLAND IN E/SE FLOW PUSHED BY OUTFLOW FROM THE EARLY
CONVECTION. HAVE KEPT LIKELY POPS OVER THE INTERIOR AND AROUND LAKE
OKEECHOBEE BUT LOWERED COASTAL VOLUSIA TO SCATTERED COVERAGE.
LIGHTNING STRIKES AND HEAVY RAINFALL WILL CONTINUE TO BE THE PRIMARY
THREATS. GUSTY WET MICROBURSTS WILL BE POSSIBLE IN THE STRONGER
STORMS.
&&
.AVIATION...VERY MOIST ATMOS REQUIRES PREVAILING VCSH/VCTS AT
COASTAL SITES THIS MORNING SHIFTING TO THE INTERIOR BY AFTN WITH
TEMPO GROUPS IN THE MID TO LATE AFTN.
&&
.MARINE...
NO SIGNIFICANT CHANGE TO CURRENT COASTAL WATERS FORECAST.
TODAY/TONIGHT...THE PRESSURE GRADIENT ONLY STRONG ENOUGH TO YIELD
EAST TO SOUTHEAST WINDS 10 TO 15 KNOTS. SEAS 1 TO 2 FEET NEARSHORE
AND 2 TO 3 FEET OFFSHORE. BECAUSE OF FETCH AND DURATION FACTORS MAY
SEE A SMALL LONG PERIOD SWELL COMPONENT SNEAKING INTO THE COMBINE
SEA HEIGHT MON/TUE. MAJOR IMPACT WOULD BE TO RIP CURRENT STRENGTH.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 87 76 88 75 / 60 30 70 30
MCO 91 75 91 75 / 70 30 60 30
MLB 89 76 89 76 / 60 30 50 20
VRB 89 74 88 74 / 50 30 40 20
LEE 90 76 90 77 / 70 30 70 30
SFB 89 74 90 75 / 70 30 60 30
ORL 90 75 90 76 / 70 30 60 30
FPR 89 75 89 75 / 50 30 40 20
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
KELLY/BRAGAW
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1025 PM CDT MON AUG 17 2015
.UPDATE...
847 PM CDT
THUNDERSTORMS CONTINUE TO FIRE THIS EVENING ALONG VARIOUS
BOUNDARIES. THE MAIN BOUNDARY EXTENDS FROM CENTRAL COOK COUNTY
THROUGH SOUTHERN DUPAGE INTO NORTHERN KENDALL. LATEST RAP
ANALYSIS INDICATES WE HAVE AROUND 500 J/KG OF CAPE TO WORK WITH
ALONG THE BOUNDARY SO ADDITIONAL ISOLATED TO SCATTERED STORMS ARE
POSSIBLE. THIS IS ESPECIALLY TRUE AS THE CURRENT STORMS PRODUCE
THEIR OWN BOUNDARIES. WITH LONG SKINNY CAPE VALUES IN FORECAST AND
00Z SOUNDINGS...EXPECTING ONLY THE STRONGEST STORMS TO PRODUCE
WIND GUSTS UP TO 50-60 MPH AND SMALL HAIL. ALL STORMS HOWEVER WILL
PRODUCE TORRENTIAL RAINFALL. THUS FAR MOST OF THE STORMS HAVE
EITHER BEEN MOVING OR WEAKENING JUST FAST ENOUGH TO AVOID FLOODING
ISSUES...BUT WILL CONTINUE TO MONITOR FOR TRAINING STORMS THAT
COULD PRODUCE FLASH FLOODING AND STANDING WATER.
STILL HAVE LOW CONFIDENCE IN EXACTLY HOW THE REST OF THE EVENING
WILL PROGRESS IN REGARDS TO STORMS. THE HRRR HAS DONE A VERY GOOD
JOB AT CAPTURING MOST OF WHAT HAS HAPPENED THUS FAR SO POP
FORECAST IS MOSTLY BASED OFF OF IT. EXPECTING MORE SCATTERED PULSE
CONVECTION ALONG THE OUTFLOW BOUNDARIES WHILE THE AREA OF
CONVECTION OVER WESTERN IL SPREADS EAST. THINKING THE STORMS OVER
WESTERN IL WILL WEAKEN AS THEY SHIFT EAST...BUT MORE STORMS WILL
PROBABLY FORM ALONG ANY OUTFLOW BOUNDARIES THE ORIGINAL STORMS
PRODUCE. IN ADDITION..A SHORTWAVE TROUGH IS OVER EASTERN IOWA SO
THINKING THAT WILL HELP FORCE WAVES OF CONVECTION THROUGH THE
NIGHT. HAD A VERY DIFFICULT TIME BEING MORE DETERMINISTIC IN MY
FORECAST SIMPLY BECAUSE OF THE MESOSCALE NATURE OF THE STORMS.
THEREFORE HAVE HIGH CONFIDENCE IN SCATTERED STORMS MAINLY
NORTHWEST OF A DE MOTTE THROUGH GIBSON CITY LINE...BUT LOW
CONFIDENCE IN EXACT TIMING AND COVERAGE AT ANY GIVEN TIME.
WITH THE AMPLE MOISTURE FROM THE STORMS...KEPT PATCHY FOG GOING
AFTER MIDNIGHT.
JEE
&&
.SHORT TERM...
340 PM CDT
THROUGH TUESDAY...
SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE THIS AFTERNOON. SEVERAL
OF THE STRONGER STORMS HAVE REPORTED WIND GUSTS AROUND 50 MPH AND
SMALL HAIL...ALONG WITH MODERATE TO HEAVY DOWNPOURS AND LIKELY
LOCALLY 1 INCH PLUS RAINFALL TOTALS.
THIS ACTIVITY IS COURTESY OF SEVERAL FEATURES...THE FIRST AN UPPER
LEVEL DISTURBANCE PUSHING INTO CENTRAL INDIANA WITH A WELL DEFINED
CLOSED CIRCULATION ON WATER VAPOR SATELLITE IMAGERY. THE SECOND IS A
COLD FRONT STRETCHED SOUTHWEST FROM NORTHERN LAKE MICHIGAN...THROUGH
CENTRAL WISCONSIN...THEN ORIENTED WEST-EAST IN MOST OF IOWA. SPC
MESOANALYSIS SHOWS MODERATE INSTABILITY WITH GOOD LOW LEVEL LAPSE
RATES...BUT POOR SHEAR...AND MODEST PW VALUES. THEREFORE LOCALLY
HEAVY RAINFALL AND GUSTY WINDS WILL REMAIN THE PREDOMINANT HAZARDS
THROUGH THE AFTERNOON AND EARLY EVENING HOURS. THESE STORMS ARE
PRODUCING OUTFLOW BOUNDARIES THAT WILL LOCALLY INCREASE
CONVERGENCE SUGGESTING SCATTERED STORMS REMAIN POSSIBLE AREA-WIDE.
WHILE THE CONVECTIVE EVOLUTION IS STILL A BIT UNCERTAIN...EXPECT A
DIURNAL DECREASE IN THE COVERAGE AWAY FROM THE COLD FRONT AS THE
UPPER LEVEL LOW ENTERS INDIANA EXITS TO THE EAST...ESPECIALLY INTO
EASTERN ILLINOIS AND NORTHWEST INDIANA. ADDITIONALLY...MODEL
GUIDANCE STALLS THE FRONT OUT ALONG A DUBUQUE TO ROCKFORD TO
MILWAUKEE LINE. THE NEXT SET OF DISTURBANCES PROPAGATE PARALLEL TO
THE COLD FRONTAL BOUNDARY...THUS HAVE RETAINED HIGHEST POPS IN NORTH
CENTRAL ILLINOIS AND ALONG THE WISCONSIN BORDER. A TRAILING
DISTURBANCE IN WESTERN IOWA WILL MOVE THROUGH THE AREA OVERNIGHT
WHICH MAY ALLOW SOME FURTHER EASTWARD PROGRESSION OVERNIGHT.
HEIGHT RISES AND SUBSIDENCE IN WAKE OF THE DEPARTING DISTURBANCE BUT
BROAD SW MOIST LOWER LEVEL FLOW SUPPORTS LOWER POPS BUT A QUIETER
PERIOD IN GENERAL. A STRONG UPPER LEVEL LOW WILL BE WORKING EASTWARD
THROUGH THE CENTRAL PLAINS ON TUESDAY. WHILE THE STRONGEST STORMS
APPEAR TO BE IN IOWA...SOME MAY SNEAK INTO OUR AREA AS WELL LATER IN
THE DAY...BUT MORE LIKELY IN THE EVENING. WEAK INSTABILITY WILL BE
PRESENT DURING THE DAY COUPLED WITH INCREASING SHEAR AND MAY SUPPORT
SCATTERED DEVELOPMENT AGAIN DURING THE AFTERNOON.
KMD
&&
.LONG TERM...
310 PM CDT
TUESDAY NIGHT THROUGH THURSDAY...
THE PERIOD WILL BEGIN FAIRLY ACTIVE AS A NOW CLOSED UPPER LEVEL
SYSTEM CONTINUES TO SLOWLY PROGRESS EAST THROUGH THE NORTHERN
PLAINS AND UPPER MIDWEST. GUIDANCE IN FAIR AGREEMENT WITH OVERALL
EVOLUTION/PLACEMENT OF THIS SYSTEM AS WELL SEVERAL IMPULSES
LIFTING NORTHEAST ACROSS THE CWA/REGION...WHILE SURFACE LOW AND
BOUNDARY REMAIN WELL TO THE NORTHWEST AND WEST DURING THIS TIME.
ALTHOUGH PLACEMENT OF STRONGER AND MORE WIDESPREAD THUNDERSTORM
DEVELOPMENT WILL INITIALLY BE SITUATED WEST OF THE
CWA...INCREASING MOISTURE AND INSTABILITY OUT AHEAD OF THIS SYSTEM
TUESDAY/TUESDAY NIGHT WHILE PERSISTENT FORCING IS PRESENT COULD
ALLOW FOR SCATTERED DEVELOPMENT ACROSS THE CWA. FOCUS WILL THEN
SHIFT TOWARDS MORE WIDESPREAD DEVELOPMENT APPROACHING OUT AHEAD OF
EASTWARD MOVING FRONTAL BOUNDARY OVER IOWA. THESE
THUNDERSTORMS...DEVELOPING THROUGHOUT THE DAY TUESDAY...WILL BE
APPROACHING THE CWA BY THE MID TO LATE EVENING TIME FRAME. WITH
PERSISTENT FORCING THROUGHOUT THE NIGHT...WOULD EXPECT SHOWERS AND
THUNDERSTORMS TO BE POSSIBLE OVER MUCH OF THE CWA. ALTHOUGH
CONFIDENCE IS HIGHER WITH COVERAGE...CONFIDENCE IS LOWER WITH
REGARD TO INTENSITY OF THESE STORMS. QUESTIONS AS TO HOW MUCH THE
ATMOSPHERE WILL DESTABILIZE ON TUESDAY WILL PLAY A FACTOR WITH
INTENSITY MAINTAINING ITSELF WEDNESDAY EVENING. DO THINK AT LEAST
A FEW/ISOLATED STRONGER STORMS WILL BE POSSIBLE...BUT WILL NEED TO
MONITOR FOR POSSIBLE HIGHER COVERAGE OF THESE STRONGER STORMS.
WHILE FRONTAL BOUNDARY WILL CONTINUE TO PUSH EAST WEDNESDAY
MORNING...THUNDERSTORM CHANCES WILL BE ENDING FROM WEST TO EAST
WITH THE ARRIVAL OF MUCH DRIER AIR ON BACKSIDE OF THIS SYSTEM.
HOWEVER...THERE IS SOME VARIABILITY WITH HOW QUICKLY THIS FRONT
PUSHES THROUGH. WITH THIS SYSTEM CLOSING ITSELF OFF...I AM A
LITTLE CONCERNED THAT A MORE PREFERRED SOLUTION WOULD BE FOR A
SLOWER TIME FRAME. IF THIS WERE TO OCCUR...THEN THERE WOULD BE AN
ADDITIONAL CHANCE FOR STRONG TO SEVERE THUNDERSTORMS ACROSS THE
EASTERN CWA WEDNESDAY AS MOISTURE/INSTABILITY WOULD CONTINUE TO
STREAM NORTHWARD OUT AHEAD OF IT. HOWEVER...WOULD THINK ALREADY
PRESENT CLOUD COVER AND PRECIP WOULD LIMIT HOW UNSTABLE THE CWA
WOULD BE...WITH BETTER INSTABILITY LIKELY STAYING EAST OF THE CWA.
THUNDERSTORM CHANCES WILL LIKELY DIMINISH FROM WEST TO EAST IN THE
AFTERNOON AND ALTHOUGH PRECIP CHANCES MAY LINGER IN THE
EVENING...THUNDER SHOULD STAY TO THE EAST. HIGH TEMPERATURES ON
WEDNESDAY WILL LIKELY OCCUR EARLY IN THE DAY WEDNESDAY AND WHILE
STRONGER WESTERLY WINDS INCREASE INTO THE AFTERNOON. DESPITE SOME
TIMING DIFFERENCE WITH THE EVOLUTION OF THIS LARGE SYSTEM...WITH
DRIER AIR WORKING IN AND BETTER FORCING EXITING...THURSDAY IS
APPEARING TO BE DRY.
RODRIGUEZ
THURSDAY NIGHT THROUGH MONDAY
THE MAIN POINT OF INTEREST FOR THE REST OF THIS WEEK AND INTO THE
WEEKEND IS AN UPPER LEVEL DISTURBANCE AND ASSOCIATED SFC LOW.
WATER VAPOR SATELLITE SHOWS A MID-LEVEL TROUGH DEVELOPING OVER THE
DAKOTAS THAT WILL PROGRESS EAST THROUGH THE UPPER GREAT LAKES
REGION THE NEXT COUPLE OF DAYS. BOTH NAM AND GFS GUIDANCE ARE IN
RATHER GOOD AGREEMENT WITH THE TIMING AND INTENSITY OF THIS
DISTURBANCE. THIS TAKES THE CENTER OF THE LOW NORTH OF THE CWA
THROUGH MN AND WI. POPS ARE PROBABLE WITH THIS SETUP WITH EMBEDDED
WAVES WITHIN THE TROUGH, HOWEVER THERE IS UNCERTAINTY AS TO THE
AMOUNT OF POPS THE AREA WILL SEE WITH THIS DISTURBANCE. SATURDAY
LOOKS TO BE THE FAVORABLE DAY FOR CONVECTION WITH AN ISOLATED
THUNDERSTORM. COVERAGE OF TSRA WILL LIKELY BE SMALL. EXPECT TEMPS
TO DROP WITH FROPA BUT RECOVER BACK INTO THE 80S WITH SWLY FLOW AT
THE SFC. DEWPOINTS LOOK TO STAY PUT IN THE LOWER TO MID 60S. THE
SFC LOW WILL LEAD TO DEVELOPMENT OF STRONG PRESSURE GRADIENT
FAVORING STRONG WIND GUSTS AS THIS DISTURBANCE PROGRESSES ACROSS
THE REGION.
KRULL
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* CHANCE OF TSRA THRU TUESDAY MORNING.
* CHANCE OF TSRA TUESDAY EVENING/TUESDAY NIGHT.
* POSSIBLE MVFR CIGS/VIS OVERNIGHT/TUESDAY MORNING. CMS
//DISCUSSION...UPDATED 03Z...
THUNDERSTORMS DEVELOPED BETWEEN 01Z AND 02Z BETWEEN ORD AND MDW
AND CONTINUE TO SLOWLY DISSIPATE. CONVECTIVE TRENDS FOR THE REST
OF THE NIGHT AND INTO TUESDAY MORNING ARE UNCERTAIN. CURRENT
THUNDERSTORM ACTIVITY FROM DKB SOUTH TO VYS AND PNT CONTINUES TO
MOVE EAST/NORTHEAST WITH OUTFLOW BOUNDARIES AHEAD OF IT...WHICH
ARE ALLOWING ADDITIONAL ISOLATED THUNDERSTORMS TO DEVELOP.
CONTINUED TS MENTION THRU 06Z FOR THIS ACTIVITY WITH DEVELOPMENT
AHEAD OF IT POSSIBLE. STILL APPEARS THUNDERSTORMS WILL FESTER
OVERNIGHT INTO TUESDAY MORNING. CMS
PREVIOUS 00Z DISCUSSION...
PRIMARY FORECAST CONCERN/CHALLENGE THRU THE PERIOD IS THE CHANCE
AND TIMING OF THUNDERSTORMS. OVERALL...FAIRLY LOW CONFIDENCE WITH
CONVECTIVE TRENDS. CURRENT ACTIVITY HAS REMAINED OUTSIDE OF THE
IMMEDIATE CHICAGO METRO AREA BUT ACTIVITY TO THE SOUTH AND WEST
MAY HOLD TOGETHER TO REACH THE CHICAGO AREA BY 02Z. MOVED UP THE
VICINITY TIMING BUT TRENDS WILL NEED TO BE MONITORED. GUSTY/
ERRATIC WINDS CAN BE EXPECTED IF ANY THUNDERSTORMS DO REACH THE
TERMINALS. ACTIVITY THIS EVENING WILL LIKELY HAVE SOME IMPACT ON
ACTIVITY OVERNIGHT INTO TUESDAY MORNING...BUT ANOTHER PERIOD OF
THUNDERSTORMS IS POSSIBLE TOWARD DAYBREAK TUESDAY. BEYOND THIS...
IT APPEARS MUCH OF THE DAYTIME TUESDAY COULD BE RATHER QUIET...AT
LEAST THRU EARLY AFTERNOON. CONVECTION IS LIKELY TO DEVELOP WEST
OF THE TERMINALS DURING THE AFTERNOON AND THEN SPREAD ACROSS THE
AREA LATE IN THE AFTERNOON OR MORE LIKELY DURING THE EVENING.
WITH TODAYS RAIN AND LIGHT WINDS OVERNIGHT...AS TEMPS COOL TOWARD
THE DEWPOINTS...COULD SEE SOME PATCHY FOG ESPECIALLY IN THE
FAVORED/OUTLYING AREAS IN ADDITION TO MVFR CIGS. CONFIDENCE ON HOW
WIDESPREAD FOG AND CIGS MAY BECOME IS LOW. TRENDS WILL NEED TO BE
MONITORED AGAIN OVERNIGHT. ANY CIGS/FOG THAT DO DEVELOP SHOULD
LIFT AND SCATTER MID/LATE TUESDAY MORNING.
LIGHT SOUTHWESTERLY WINDS THIS EVENING WILL LIKELY BECOME VARIABLE
OVERNIGHT AND THEN TURN SOUTHEASTERLY TUESDAY MORNING. SPEEDS MAY
APPROACH 10KTS DURING THE AFTERNOON. CMS
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* MEDIUM FOR TSRA THRU TUESDAY MORNING...LOW FOR COVERAGE/TIMING.
* LOW FOR MVFR CIGS/VIS OVERNIGHT/TUESDAY MORNING. CMS
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
* WEDNESDAY...CHANCE OF TSRA. STRONG/GUSTY SOUTHWEST WINDS.
* THURSDAY...DRY/VFR. STRONG/GUSTY WESTERLY WINDS.
* FRIDAY...DRY/VFR. SOUTH/SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. SOUTH/SOUTHEAST WINDS.
* SUNDAY...CHANCE OF TSRA. SOUTHWEST WINDS.
&&
.MARINE...
344 PM CDT
VARYING WINDS ACROSS THE LAKE THIS AFTERNOON ARE DUE TO LINGERING
BOUNDARY SITUATED OVER THE LAKE WHILE SURFACE LOW/TROUGH REMAINS
TO THE WEST. THESE VARYING WINDS WILL LIKELY PERSIST ON TUESDAY
AND INTO A PORTION OF TUESDAY NIGHT...BEFORE WINDS ACROSS THE
ENTIRE LAKE TURN MORE SOUTHERLY TUESDAY NIGHT INTO WEDNESDAY. THIS
WILL BE IN RESPONSE TO APPROACHING AND STRENGTHENING SURFACE LOW
OVER THE UPPER MIDWEST. EXPECT SPEEDS TO BE INCREASING TUESDAY
NIGHT BUT EXPECT SPEEDS TO REALLY RAMP UP ON WEDNESDAY AND
ESPECIALLY WEDNESDAY NIGHT AS THIS LOW FURTHER
STRENGTHENS/APPROACHES. HAVE MAINTAINED TO 30 KT WINDS ACROSS THE
LAKE...BUT AM A LITTLE CONCERNED THAT A PERIOD OF AT LEAST GALE
FORCE GUSTS WILL BE POSSIBLE...ESPECIALLY WEDNESDAY NIGHT. THESE
STRONGER WINDS WILL LIKELY BE PRESENT ACROSS THE NEARSHORE
WEDNESDAY INTO WEDNESDAY EVENING...BUT THESE HIGHER GUSTS MAY BE
POSSIBLE WELL INTO WEDNESDAY NIGHT. ALTHOUGH THESE STRONGER WINDS
MAY STILL BE OCCURRING THURSDAY MORNING...EXPECT SPEEDS TO BE
LOWERING INTO THE AFTERNOON.
RODRIGUEZ
&&
.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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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
921 PM CDT MON AUG 17 2015
.UPDATE...
847 PM CDT
THUNDERSTORMS CONTINUE TO FIRE THIS EVENING ALONG VARIOUS
BOUNDARIES. THE MAIN BOUNDARY EXTENDS FROM CENTRAL COOK COUNTY
THROUGH SOUTHERN DUPAGE INTO NORTHERN KENDALL. LATEST RAP
ANALYSIS INDICATES WE HAVE AROUND 500 J/KG OF CAPE TO WORK WITH
ALONG THE BOUNDARY SO ADDITIONAL ISOLATED TO SCATTERED STORMS ARE
POSSIBLE. THIS IS ESPECIALLY TRUE AS THE CURRENT STORMS PRODUCE
THEIR OWN BOUNDARIES. WITH LONG SKINNY CAPE VALUES IN FORECAST AND
00Z SOUNDINGS...EXPECTING ONLY THE STRONGEST STORMS TO PRODUCE
WIND GUSTS UP TO 50-60 MPH AND SMALL HAIL. ALL STORMS HOWEVER WILL
PRODUCE TORRENTIAL RAINFALL. THUS FAR MOST OF THE STORMS HAVE
EITHER BEEN MOVING OR WEAKENING JUST FAST ENOUGH TO AVOID FLOODING
ISSUES...BUT WILL CONTINUE TO MONITOR FOR TRAINING STORMS THAT
COULD PRODUCE FLASH FLOODING AND STANDING WATER.
STILL HAVE LOW CONFIDENCE IN EXACTLY HOW THE REST OF THE EVENING
WILL PROGRESS IN REGARDS TO STORMS. THE HRRR HAS DONE A VERY GOOD
JOB AT CAPTURING MOST OF WHAT HAS HAPPENED THUS FAR SO POP
FORECAST IS MOSTLY BASED OFF OF IT. EXPECTING MORE SCATTERED PULSE
CONVECTION ALONG THE OUTFLOW BOUNDARIES WHILE THE AREA OF
CONVECTION OVER WESTERN IL SPREADS EAST. THINKING THE STORMS OVER
WESTERN IL WILL WEAKEN AS THEY SHIFT EAST...BUT MORE STORMS WILL
PROBABLY FORM ALONG ANY OUTFLOW BOUNDARIES THE ORIGINAL STORMS
PRODUCE. IN ADDITION..A SHORTWAVE TROUGH IS OVER EASTERN IOWA SO
THINKING THAT WILL HELP FORCE WAVES OF CONVECTION THROUGH THE
NIGHT. HAD A VERY DIFFICULT TIME BEING MORE DETERMINISTIC IN MY
FORECAST SIMPLY BECAUSE OF THE MESOSCALE NATURE OF THE STORMS.
THEREFORE HAVE HIGH CONFIDENCE IN SCATTERED STORMS MAINLY
NORTHWEST OF A DE MOTTE THROUGH GIBSON CITY LINE...BUT LOW
CONFIDENCE IN EXACT TIMING AND COVERAGE AT ANY GIVEN TIME.
WITH THE AMPLE MOISTURE FROM THE STORMS...KEPT PATCHY FOG GOING
AFTER MIDNIGHT.
JEE
&&
.SHORT TERM...
340 PM CDT
THROUGH TUESDAY...
SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE THIS AFTERNOON. SEVERAL
OF THE STRONGER STORMS HAVE REPORTED WIND GUSTS AROUND 50 MPH AND
SMALL HAIL...ALONG WITH MODERATE TO HEAVY DOWNPOURS AND LIKELY
LOCALLY 1 INCH PLUS RAINFALL TOTALS.
THIS ACTIVITY IS COURTESY OF SEVERAL FEATURES...THE FIRST AN UPPER
LEVEL DISTURBANCE PUSHING INTO CENTRAL INDIANA WITH A WELL DEFINED
CLOSED CIRCULATION ON WATER VAPOR SATELLITE IMAGERY. THE SECOND IS A
COLD FRONT STRETCHED SOUTHWEST FROM NORTHERN LAKE MICHIGAN...THROUGH
CENTRAL WISCONSIN...THEN ORIENTED WEST-EAST IN MOST OF IOWA. SPC
MESOANALYSIS SHOWS MODERATE INSTABILITY WITH GOOD LOW LEVEL LAPSE
RATES...BUT POOR SHEAR...AND MODEST PW VALUES. THEREFORE LOCALLY
HEAVY RAINFALL AND GUSTY WINDS WILL REMAIN THE PREDOMINANT HAZARDS
THROUGH THE AFTERNOON AND EARLY EVENING HOURS. THESE STORMS ARE
PRODUCING OUTFLOW BOUNDARIES THAT WILL LOCALLY INCREASE
CONVERGENCE SUGGESTING SCATTERED STORMS REMAIN POSSIBLE AREA-WIDE.
WHILE THE CONVECTIVE EVOLUTION IS STILL A BIT UNCERTAIN...EXPECT A
DIURNAL DECREASE IN THE COVERAGE AWAY FROM THE COLD FRONT AS THE
UPPER LEVEL LOW ENTERS INDIANA EXITS TO THE EAST...ESPECIALLY INTO
EASTERN ILLINOIS AND NORTHWEST INDIANA. ADDITIONALLY...MODEL
GUIDANCE STALLS THE FRONT OUT ALONG A DUBUQUE TO ROCKFORD TO
MILWAUKEE LINE. THE NEXT SET OF DISTURBANCES PROPAGATE PARALLEL TO
THE COLD FRONTAL BOUNDARY...THUS HAVE RETAINED HIGHEST POPS IN NORTH
CENTRAL ILLINOIS AND ALONG THE WISCONSIN BORDER. A TRAILING
DISTURBANCE IN WESTERN IOWA WILL MOVE THROUGH THE AREA OVERNIGHT
WHICH MAY ALLOW SOME FURTHER EASTWARD PROGRESSION OVERNIGHT.
HEIGHT RISES AND SUBSIDENCE IN WAKE OF THE DEPARTING DISTURBANCE BUT
BROAD SW MOIST LOWER LEVEL FLOW SUPPORTS LOWER POPS BUT A QUIETER
PERIOD IN GENERAL. A STRONG UPPER LEVEL LOW WILL BE WORKING EASTWARD
THROUGH THE CENTRAL PLAINS ON TUESDAY. WHILE THE STRONGEST STORMS
APPEAR TO BE IN IOWA...SOME MAY SNEAK INTO OUR AREA AS WELL LATER IN
THE DAY...BUT MORE LIKELY IN THE EVENING. WEAK INSTABILITY WILL BE
PRESENT DURING THE DAY COUPLED WITH INCREASING SHEAR AND MAY SUPPORT
SCATTERED DEVELOPMENT AGAIN DURING THE AFTERNOON.
KMD
&&
.LONG TERM...
310 PM CDT
TUESDAY NIGHT THROUGH THURSDAY...
THE PERIOD WILL BEGIN FAIRLY ACTIVE AS A NOW CLOSED UPPER LEVEL
SYSTEM CONTINUES TO SLOWLY PROGRESS EAST THROUGH THE NORTHERN
PLAINS AND UPPER MIDWEST. GUIDANCE IN FAIR AGREEMENT WITH OVERALL
EVOLUTION/PLACEMENT OF THIS SYSTEM AS WELL SEVERAL IMPULSES
LIFTING NORTHEAST ACROSS THE CWA/REGION...WHILE SURFACE LOW AND
BOUNDARY REMAIN WELL TO THE NORTHWEST AND WEST DURING THIS TIME.
ALTHOUGH PLACEMENT OF STRONGER AND MORE WIDESPREAD THUNDERSTORM
DEVELOPMENT WILL INITIALLY BE SITUATED WEST OF THE
CWA...INCREASING MOISTURE AND INSTABILITY OUT AHEAD OF THIS SYSTEM
TUESDAY/TUESDAY NIGHT WHILE PERSISTENT FORCING IS PRESENT COULD
ALLOW FOR SCATTERED DEVELOPMENT ACROSS THE CWA. FOCUS WILL THEN
SHIFT TOWARDS MORE WIDESPREAD DEVELOPMENT APPROACHING OUT AHEAD OF
EASTWARD MOVING FRONTAL BOUNDARY OVER IOWA. THESE
THUNDERSTORMS...DEVELOPING THROUGHOUT THE DAY TUESDAY...WILL BE
APPROACHING THE CWA BY THE MID TO LATE EVENING TIME FRAME. WITH
PERSISTENT FORCING THROUGHOUT THE NIGHT...WOULD EXPECT SHOWERS AND
THUNDERSTORMS TO BE POSSIBLE OVER MUCH OF THE CWA. ALTHOUGH
CONFIDENCE IS HIGHER WITH COVERAGE...CONFIDENCE IS LOWER WITH
REGARD TO INTENSITY OF THESE STORMS. QUESTIONS AS TO HOW MUCH THE
ATMOSPHERE WILL DESTABILIZE ON TUESDAY WILL PLAY A FACTOR WITH
INTENSITY MAINTAINING ITSELF WEDNESDAY EVENING. DO THINK AT LEAST
A FEW/ISOLATED STRONGER STORMS WILL BE POSSIBLE...BUT WILL NEED TO
MONITOR FOR POSSIBLE HIGHER COVERAGE OF THESE STRONGER STORMS.
WHILE FRONTAL BOUNDARY WILL CONTINUE TO PUSH EAST WEDNESDAY
MORNING...THUNDERSTORM CHANCES WILL BE ENDING FROM WEST TO EAST
WITH THE ARRIVAL OF MUCH DRIER AIR ON BACKSIDE OF THIS SYSTEM.
HOWEVER...THERE IS SOME VARIABILITY WITH HOW QUICKLY THIS FRONT
PUSHES THROUGH. WITH THIS SYSTEM CLOSING ITSELF OFF...I AM A
LITTLE CONCERNED THAT A MORE PREFERRED SOLUTION WOULD BE FOR A
SLOWER TIME FRAME. IF THIS WERE TO OCCUR...THEN THERE WOULD BE AN
ADDITIONAL CHANCE FOR STRONG TO SEVERE THUNDERSTORMS ACROSS THE
EASTERN CWA WEDNESDAY AS MOISTURE/INSTABILITY WOULD CONTINUE TO
STREAM NORTHWARD OUT AHEAD OF IT. HOWEVER...WOULD THINK ALREADY
PRESENT CLOUD COVER AND PRECIP WOULD LIMIT HOW UNSTABLE THE CWA
WOULD BE...WITH BETTER INSTABILITY LIKELY STAYING EAST OF THE CWA.
THUNDERSTORM CHANCES WILL LIKELY DIMINISH FROM WEST TO EAST IN THE
AFTERNOON AND ALTHOUGH PRECIP CHANCES MAY LINGER IN THE
EVENING...THUNDER SHOULD STAY TO THE EAST. HIGH TEMPERATURES ON
WEDNESDAY WILL LIKELY OCCUR EARLY IN THE DAY WEDNESDAY AND WHILE
STRONGER WESTERLY WINDS INCREASE INTO THE AFTERNOON. DESPITE SOME
TIMING DIFFERENCE WITH THE EVOLUTION OF THIS LARGE SYSTEM...WITH
DRIER AIR WORKING IN AND BETTER FORCING EXITING...THURSDAY IS
APPEARING TO BE DRY.
RODRIGUEZ
THURSDAY NIGHT THROUGH MONDAY
THE MAIN POINT OF INTEREST FOR THE REST OF THIS WEEK AND INTO THE
WEEKEND IS AN UPPER LEVEL DISTURBANCE AND ASSOCIATED SFC LOW.
WATER VAPOR SATELLITE SHOWS A MID-LEVEL TROUGH DEVELOPING OVER THE
DAKOTAS THAT WILL PROGRESS EAST THROUGH THE UPPER GREAT LAKES
REGION THE NEXT COUPLE OF DAYS. BOTH NAM AND GFS GUIDANCE ARE IN
RATHER GOOD AGREEMENT WITH THE TIMING AND INTENSITY OF THIS
DISTURBANCE. THIS TAKES THE CENTER OF THE LOW NORTH OF THE CWA
THROUGH MN AND WI. POPS ARE PROBABLE WITH THIS SETUP WITH EMBEDDED
WAVES WITHIN THE TROUGH, HOWEVER THERE IS UNCERTAINTY AS TO THE
AMOUNT OF POPS THE AREA WILL SEE WITH THIS DISTURBANCE. SATURDAY
LOOKS TO BE THE FAVORABLE DAY FOR CONVECTION WITH AN ISOLATED
THUNDERSTORM. COVERAGE OF TSRA WILL LIKELY BE SMALL. EXPECT TEMPS
TO DROP WITH FROPA BUT RECOVER BACK INTO THE 80S WITH SWLY FLOW AT
THE SFC. DEWPOINTS LOOK TO STAY PUT IN THE LOWER TO MID 60S. THE
SFC LOW WILL LEAD TO DEVELOPMENT OF STRONG PRESSURE GRADIENT
FAVORING STRONG WIND GUSTS AS THIS DISTURBANCE PROGRESSES ACROSS
THE REGION.
KRULL
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* CHANCE OF TSRA MID/LATE THIS EVENING.
* CHANCE OF TSRA OVERNIGHT/TUESDAY MORNING.
* CHANCE OF TSRA TUESDAY EVENING.
* POSSIBLE MVFR CIGS/VIS OVERNIGHT/TUESDAY MORNING. CMS
//DISCUSSION...UPDATED 00Z...
PRIMARY FORECAST CONCERN/CHALLENGE THRU THE PERIOD IS THE CHANCE
AND TIMING OF THUNDERSTORMS. OVERALL...FAIRLY LOW CONFIDENCE WITH
CONVECTIVE TRENDS. CURRENT ACTIVITY HAS REMAINED OUTSIDE OF THE
IMMEDIATE CHICAGO METRO AREA BUT ACTIVITY TO THE SOUTH AND WEST
MAY HOLD TOGETHER TO REACH THE CHICAGO AREA BY 02Z. MOVED UP THE
VICINITY TIMING BUT TRENDS WILL NEED TO BE MONITORED. GUSTY/
ERRATIC WINDS CAN BE EXPECTED IF ANY THUNDERSTORMS DO REACH THE
TERMINALS. ACTIVITY THIS EVENING WILL LIKELY HAVE SOME IMPACT ON
ACTIVITY OVERNIGHT INTO TUESDAY MORNING...BUT ANOTHER PERIOD OF
THUNDERSTORMS IS POSSIBLE TOWARD DAYBREAK TUESDAY. BEYOND THIS...
IT APPEARS MUCH OF THE DAYTIME TUESDAY COULD BE RATHER QUIET...AT
LEAST THRU EARLY AFTERNOON. CONVECTION IS LIKELY TO DEVELOP WEST
OF THE TERMINALS DURING THE AFTERNOON AND THEN SPREAD ACROSS THE
AREA LATE IN THE AFTERNOON OR MORE LIKELY DURING THE EVENING.
WITH TODAYS RAIN AND LIGHT WINDS OVERNIGHT...AS TEMPS COOL TOWARD
THE DEWPOINTS...COULD SEE SOME PATCHY FOG ESPECIALLY IN THE
FAVORED/OUTLYING AREAS IN ADDITION TO MVFR CIGS. CONFIDENCE ON HOW
WIDESPREAD FOG AND CIGS MAY BECOME IS LOW. TRENDS WILL NEED TO BE
MONITORED AGAIN OVERNIGHT. ANY CIGS/FOG THAT DO DEVELOP SHOULD
LIFT AND SCATTER MID/LATE TUESDAY MORNING.
LIGHT SOUTHWESTERLY WINDS THIS EVENING WILL LIKELY BECOME VARIABLE
OVERNIGHT AND THEN TURN SOUTHEASTERLY TUESDAY MORNING. SPEEDS MAY
APPROACH 10KTS DURING THE AFTERNOON. CMS
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* LOW FOR TSRA CHANCES/TIMING THRU THE PERIOD.
* LOW FOR MVFR CIGS/VIS OVERNIGHT/TUESDAY MORNING. CMS
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
* WEDNESDAY...CHANCE OF TSRA. STRONG/GUSTY SOUTHWEST WINDS.
* THURSDAY...DRY/VFR. STRONG/GUSTY WESTERLY WINDS.
* FRIDAY...DRY/VFR. SOUTH/SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. SOUTH/SOUTHEAST WINDS.
* SUNDAY...CHANCE OF TSRA. SOUTHWEST WINDS.
&&
.MARINE...
344 PM CDT
VARYING WINDS ACROSS THE LAKE THIS AFTERNOON ARE DUE TO LINGERING
BOUNDARY SITUATED OVER THE LAKE WHILE SURFACE LOW/TROUGH REMAINS
TO THE WEST. THESE VARYING WINDS WILL LIKELY PERSIST ON TUESDAY
AND INTO A PORTION OF TUESDAY NIGHT...BEFORE WINDS ACROSS THE
ENTIRE LAKE TURN MORE SOUTHERLY TUESDAY NIGHT INTO WEDNESDAY. THIS
WILL BE IN RESPONSE TO APPROACHING AND STRENGTHENING SURFACE LOW
OVER THE UPPER MIDWEST. EXPECT SPEEDS TO BE INCREASING TUESDAY
NIGHT BUT EXPECT SPEEDS TO REALLY RAMP UP ON WEDNESDAY AND
ESPECIALLY WEDNESDAY NIGHT AS THIS LOW FURTHER
STRENGTHENS/APPROACHES. HAVE MAINTAINED TO 30 KT WINDS ACROSS THE
LAKE...BUT AM A LITTLE CONCERNED THAT A PERIOD OF AT LEAST GALE
FORCE GUSTS WILL BE POSSIBLE...ESPECIALLY WEDNESDAY NIGHT. THESE
STRONGER WINDS WILL LIKELY BE PRESENT ACROSS THE NEARSHORE
WEDNESDAY INTO WEDNESDAY EVENING...BUT THESE HIGHER GUSTS MAY BE
POSSIBLE WELL INTO WEDNESDAY NIGHT. ALTHOUGH THESE STRONGER WINDS
MAY STILL BE OCCURRING THURSDAY MORNING...EXPECT SPEEDS TO BE
LOWERING INTO THE AFTERNOON.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS GOODLAND KS
518 PM MDT MON AUG 17 2015
.UPDATE...
ISSUED AT 504 PM MDT MON AUG 17 2015
ADVANCING COLD FRONT/COLD POOL FROM THE NORTHEAST HAS CLEARED ST
FRANCIS AND COLBY AND RAPIDLY HEADING TOWARDS THE GLD AREA. IN
ADDITION TO THE WIND SHIFT AND EVEN MORE INCREASED LOW LEVEL
SHEAR...MESOANALYSIS INDICATES STRONG CINH IN COOLER AIR TO THE
NORTH. THINK THIS WILL FOR AT LEAST A WHILE ACT AS A NORTHERN
LIMIT TO SFC BASED CONVECTION AND HAVE HIGHLIGHTED AND INCREASED
POPS IN AREAS TO THE SOUTH OF AFOREMENTIONED FEATURE. ALTHOUGH
STORMS ARE MOVING...RAINFALL RATES AROUND AN INCH AND A HALF PER
HOUR HAVE BEEN OBSERVED KEEPING HEAVY RAIN SIG THREAT. QUICK
MOTION SHOULD LIMIT FLOOD POTENTIAL AND AT THIS TIME HAVE OPTED
AWAY FROM ANY LARGE SCALE WATCH.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 250 PM MDT MON AUG 17 2015
EARLY AFTERNOON WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW
STRENGTHENING TROUGH ACROSS MONTANA WITH SHARP PV HEIGHT ANOMALY
DIGGING INTO NORTHWESTERN WYOMING. DIFFLUENT FLOW IS IN PLACE
ACROSS NORTHERN COLORADO WITH INCREASING DIVERGENT SIGNATURE
AHEAD OF APPROACHING UPPER LEVEL JET. AT THE SURFACE A STATIONARY
FRONT EXTENDS FROM NORTH CENTRAL KANSAS TO SOUTHEAST
COLORADO...ACROSS THE SOUTHEAST PART OF OUR CWA...WITH A WEAK
SURFACE TROUGH AXIS EXPENDING ACROSS THE NW PART OF OUR FORECAST
AREA.
THUNDERSTORMS SHOULD INITIATE ACROSS EASTERN COLORADO THIS
AFTERNOON WITH ACTIVITY INCREASING IN COVERAGE AND SPREADING EAST
INTO OUR CWA THROUGH THE EVENING/OVERNIGHT. BEST FORCING IS
ADVERTISED 03-06Z OVER OUR CWA AND QUICKLY TRANSITIONS EASTWARD
THROUGH TUESDAY MORNING. AS THE UPPER LOW DEEPENS AND EVENTUALLY
CLOSES OFF OVER NEBRASKA DRY SLOT/SUBSIDENT REGION WILL MOVE OVER
OUR CWA WHICH SHOULD RAPIDLY DECREASE ANY SHOWER/THUNDERSTORM
CHANCES. STRONG COLD FRONT WILL DROP DOWN ACROSS THE REGION
TUESDAY MORNING AND COMBINED WITH INCREASING SUBSIDENCE BRING
MILD/WINDY (VERY FALL-LIKE) CONDITIONS TO OUR CWA. THERE MAY ALSO
BE A REDEVELOPMENT OF DENSE FOG/LOW STRATUS OVER SW NEBRASKA
DEPENDING ON THUNDERSTORM ACTIVITY/MIXING AND FRONTAL TIMING.
REGARDING SEVERE POTENTIAL TONIGHT...RAP ANALYSIS SHOWS SB CAPE
AXIS 2500-3500 J/KG AND DEEP BULK EFFECTIVE SHEER VALUES 40-50KT
ACROSS EASTERN COLORADO. CONSIDERING THE DEEP LAYER SHEER AND
INSTABILITY WE ARE ANTICIPATING ORGANIZED SUPERCELLS DEVELOPING
LATE THIS AFTERNOON AND SLOWLY PROGRESSING EASTWARD (MEAN STORM
MOTIONS 10-20KT). THERE IS A WINDOW WITH LOW LEVEL TURNING ALONG
SURFACE TROUGH AXIS FOR TORNADOES WITH MORE ORGANIZED CELLS...WITH
PRIMARY THREAT VERY LARGE HAIL (2"+) AND DAMAGING WINDS. AS THIS
ACTIVITY ORGANIZES INTO A MCS/THUNDERSTORM CLUSTER TORNADO THREAT
SHOULD DIMINISH. TORNADO WATCH 490 IS CURRENTLY IN EFFECT FOR OUR
EASTERN COLORADO COUNTIES...AND PATTERN IS BEING MONITORED FOR
ANY OTHER POSSIBLE SEVERE WATCHES AS THIS UNFOLDS THIS
AFTERNOON/EVENING.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 156 PM MDT MON AUG 17 2015
JET MAX ROTATING AROUND BACK OF THE UPPER TROUGH WILL BRING
SCATTERED SHOWERS TO THE AREA TUESDAY NIGHT THROUGH WEDNESDAY
MORNING UNDER THE DIVERGENT LEFT EXIT REGION. MODEL QPF IS
LIGHT...GENERALLY BETWEEN A TENTH AND A QUARTER OF AN INCH...BUT
RATHER WIDESPREAD SO POPS MAY NEED TO BE INCREASED IF THOSE TRENDS
CONTINUE. POINT FORECAST SOUNDINGS ACTUALLY SHOW ICE IN THE COLUMN
BUT THE SURFACE BASED WARM LAYER EXTENDS TO AROUND 6KFT AGL WHICH
WILL BE MORE THAN SUFFICIENT TO KEEP ANY KIND OF SNOW FROM
REACHING THE GROUND. LOW TEMPERATURES A BIT TRICKY...WITH CLOUDS
POTENTIALLY KEEPING THEM FROM REACHING THE UPPER 40S BUT IF THE
RAIN IS PROLONGED MIGHT WET BULB DOWN TO NEAR THAT ANYWAY. EITHER
WAY IT WILL BE A RATHER CHILLY MORNING FOR MID AUGUST.
UPPER TROUGH WILL MOVE OUT WEDNESDAY AFTERNOON WITH NORTHWEST
FLOW ALOFT THROUGH THE END OF THE WEEK. PRECIPITATION CHANCES
DURING THAT TIME WILL BE SLIM TO NONE WITH NO UPPER SHORTWAVES IN
THE MODELS AND LIMITED MOISTURE AVAILABLE. TEMPERATURES WILL
REBOUND QUICKLY AFTER THE MIDWEEK COOL DOWN WITH ABOVE NORMAL
HIGHS BY FRIDAY. THE UPPER FLOW WILL TRANSITION TO ZONAL AND THEN
SOUTHWEST OVER THE WEEKEND AS ANOTHER TROUGH DIGS INTO THE
NORTHERN ROCKIES. THE NEXT BEST CHANCE FOR THUNDERSTORMS WILL BE
SATURDAY AFTERNOON/EVENING AS DYNAMICS AND SURFACE COLD FRONT
ASSOCIATED WITH THAT SYSTEM MOVE THROUGH THE CENTRAL PLAINS. A
LITTLE EARLY...BUT RIGHT NOW BEST COMBINATION OF INSTABILITY AND
SHEAR WILL BE CONFINED TO EASTERN PARTS OF THE FORECAST
AREA...NORTON TO GOVE...WHICH WOULD BE THE FAVORED AREAS FOR ANY
SEVERE THREAT. IF THAT TIMING VERIFIES SUNDAY AND MONDAY WILL BE
DRY AND A LITTLE COOLER.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 504 PM MDT MON AUG 17 2015
COMPLICATED AVIATION FORECAST ONGOING ACROSS THE AREA AS ADVANCING
COLD POOL NEAR KGLD BRING A WIND SHIFT AND INCREASED
STABILITY...WHILE STRONG CONVECTIVE COMPLEX BRINGING IFR
CONDITIONSAND STRONG WINDS FROM THE WEST. STORMS WILL BE NEAR
KGLD AROUND 2 UTC...BUT THINK THE HIGH END CONDITIONS APPEAR MORE
LIKELY TO THE SOUTH OF THE TERMINAL. MCK MAY SEE A BRIEF REPRIEVE
FROM IFR CIGS BUT EXPECT STRATUS TO DEVELOP AGAIN OVERNIGHT WITH A
PROLONGED PERIODS OF CIGS LESS THAN 1000 FEET. DETAILS ARE A BIT
MURKY AND WILL REFINE AS POSSIBLE WHEN THINGS CLEAR UP.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JRM
SHORT TERM...DR
LONG TERM...024
AVIATION...JRM
AREA FORECAST DISCUSSION
NWS GOODLAND KS
252 PM MDT SUN AUG 16 2015
.SHORT TERM...(THIS AFTERNOON THROUGH MONDAY)
ISSUED AT 235 PM MDT SUN AUG 16 2015
WV IMAGERY AND RAP ANALYSIS SHOWS RIDGE CENTERED OVER SOUTHERN
CALIFORNIA WITH AXIS EXTENDING ACROSS THE HIGH PLAINS AND INTO THE
GREAT LAKES REGION. PLUMES OF MID LEVEL MOISTURE ORIGINATING IN THE
PACIFIC ARE ROTATING AROUND THE EASTERN AND NORTHERN PERIPHERY OF THE
LARGE SCALE RIDGE INTO THE ROCKIES AND HIGH PLAINS. DIFFLUENT FLOW IS
CURRENTLY IN PLACE ACROSS THE CENTRAL ROCKIES WITH TROUGH DIGGING
INTO THE NORTHERN PLAINS. A FEW WEAKER SHORTWAVE TROUGHS ARE JUST TO
THE WEST/NORTHWEST OF OUR CWA. AT THE SURFACE QUASI-STATIONARY FRONT
CURRENTLY EXTENDS ACROSS CENTRAL NEBRASKA INTO NORTHCENTRAL COLORADO
OVER THE FAR NORTHWEST PART OF OUR CWA. PREFRONTAL TROUGH AXIS IS IN
PLACE FROM SOUTHEAST COLORADO OVER GOODLAND AND NORTON KANSAS.
THIS AFTERNOON-TONIGHT...THUNDERSTORM ACTIVITY SHOULD INITIATE
WITHIN THE NEXT FEW HOURS ALONG FRONT AND SURFACE TROUGH WITH
COVERAGE INCREASING THIS EVENING AS A SERIES OF WEAK SHORTWAVE
TROUGHS ROTATE ACROSS THE REGION. RECENT TRENDS IN ARW/NMM HAVE BEEN
TO SHIFT MOST ORGANIZED THUNDERSTORM CLUSTER TO THE SOUTH ROUGHLY
ALONG AND SOUTH OF INTERSTATE 70. CURRENTLY THE ORIENTATION OF FLOW
ALOFT AND OTHER GUIDANCE STILL SHOWING THUNDERSTORM CLUSTERS
ORIGINATING FROM THE WEST OR NORTHWEST OF THIS. EITHER WAY...DEEP
MOIST AIR MASS AND DECENT INSTABILITY AHEAD OF FRONT WILL SUPPORT
ACTIVITY ACROSS MUCH OF CWA TRANSITIONING EASTWARD. STRONGEST CAPE
AXIS IF FURTHER EAST THAN PREVIOUS GUIDANCE INDICATED...THOUGH THERE
IS ENOUGH ELEVATED CAPE TO AT LEAST CONSIDER POTENTIAL FOR
MARGINALLY SEVERE HAIL. DCAPE 1000-1500 J/KG COINCIDING DRY ADIABATIC
PROFILES BELOW 700MB COULD SUPPORT ISOLATED SEVERE DOWNDRAFT
POTENTIAL DURING THE AFTERNOON...THOUGH AS MIXING RATIOS INCREASE
BELOW 700MB THIS EVENING THIS THREAT WILL LIKELY DIMINISH.
REGARDING FLASH FLOOD WATCH...ANOMALOUSLY HIGH PWAT VALUES 1.2-1.6
WILL ONLY INCREASE THROUGH THE NIGHT APPROACHING 1.7-1.8 WHICH IS
WELL WITHIN 99TH PERCENTILE OR 3 STANDARD DEVIATIONS FROM NORMAL.
WITH VERY SLOW STORM MOTIONS AND POSSIBILITY FOR
TRAINING/BACKBUILDING I AM COMFORTABLE WITH FLASH FLOOD WATCH. IF
ARW/NMM SOLUTION PANS OUT THEN WE MAY NEED TO CONSIDER ADDING
SOUTHERN PART OF FORECAST AREA TO WATCH.
MONDAY...WHILE FRONTAL PASSAGE SHOULD OCCUR FROM NORTH TO SOUTH
MONDAY...GUIDANCE IS SHOWING A LOT OF SPREAD ON TIMING. THIS LOWERS
CONFIDENCE/TIMING OF ADDITIONAL THUNDERSTORM ACTIVITY. ARW/NMM SHOW
A MORE ORGANIZED THUNDERSTORM CLUSTER DEVELOPING ALONG FRONT MONDAY
MORNING...THOUGH OTHER GUIDANCE IS SHOWING PREDOMINANTLY ISOLATED TO
SCATTERED ACTIVITY LINGERING ACROSS THE AREA. DEEP MOIST LAYER
REMAINS IN PLACE...SO WITH POTENTIAL FOR OVERRUNNING ALONG BAROCLINIC
ZONE...IT IS POSSIBLE FOR A MORE ORGANIZED CLUSTER IF WE CONTINUE TO
SEE WEAK HEIGHT FALL...WHICH COULD ALSO RESULT CONTINUING THREAT FOR
FLASH FLOODING. SEVERE THUNDERSTORM THREAT WILL BE HIGHLY DEPENDENT
ON FRONTAL POSITION/TIMING AS BETTER INSTABILITY WILL TEND TO BE
AHEAD OF FRONT. AS WITH TODAY...THREATS WOULD BE LARGE HAIL/DAMAGING
WINDS ALONG/SOUTH OF FRONT.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 252 PM MDT SUN AUG 16 2015
FOR THIS EXTENDED FORECAST PACKAGE...A STRONG COLD FRONT IS EXPECTED
TO MOVE THROUGH ON TUESDAY...BRINGING AN END TO SIGNIFICANT
PRECIPITATION CHANCES AND A TEMPORARY PARDON FROM THE WARMTH AND
HUMIDITY. ZONAL FLOW ALOFT RETURNS BEHIND TUESDAY`S SYSTEM. WITH
SOUTHERLY LOW LEVEL FLOW...A WARMING TREND IS EXPECTED TO BEGIN
THURSDAY. HOWEVER...YET ANOTHER UPPER LEVEL DISTURBANCE IS EXPECTED
TO FORCE A COLD FRONT THROUGH THIS WEEKEND...BRINING ANOTHER CHANCE
FOR BELOW NORMAL TEMPERATURES.
THE MOST IMPACTFUL WEATHER IN THE EXTENDED FORECAST PERIOD IS
ANTICIPATED MONDAY EVENING THROUGH TUESDAY EVENING. ACTIVE WEATHER
IS FORECAST AS A LARGE NEGATIVELY TILTED TROUGH KICKS OUT OVER THE
HIGH PLAINS. STRONG/SEVERE THUNDERSTORMS MAY BE ONGOING ACROSS
PORTIONS OF THE REGION MONDAY EVENING DEPENDING ON THE FRONT
LOCATION AND ENVIRONMENTAL PARAMETERS. ANY POTENTIAL SEVERE WEATHER
THREAT MAY BE HIGHER MONDAY EVENING AS INITIAL DEVELOPMENT IN
COLORADO SHOULD BE MOVING IN. THE PRIMARY THREATS FOR SEVERE WEATHER
WILL BE LARGE HAIL AND DAMAGING WINDS. AS MENTIONED IN THE DAY 2
STORM PREDICTION CENTER OUTLOOK...SURFACE VORTICITY/HELICITY
MAXIMIZED IN THE VICINITY OF THE FRONT MAY PROVIDE AN OPPORTUNITY
FOR A TORNADO TO OCCUR. CONFIDENCE IN THIS ISN`T AS HIGH AS HIGHER
RESOLUTION GUIDANCE INDICATES THE POTENTIAL FOR COLD POOL
DEVELOPMENT...HIGHLIGHTING A HIGHER THREAT OF MCS DEVELOPMENT WITH
DAMAGING WINDS AS THE MAIN THREAT. IN TERMS OF FLASH FLOODING...A
THREAT WILL STILL EXIST ESPECIALLY IF HEAVY RAINS ARE RECEIVED
TONIGHT. PRECIPITABLE WATER VALUES FALL AS THE FRONT DOES FORCE SOME
MOISTURE SOUTH SO WE NO LONGER EXPECT PRECIPITABLE WATER VALUES
NEARING THE 99TH PERCENTILE. STORM MOVEMENT REMAINS QUITE SLOW IN
TERMS OF STEERING WINDS ALOFT SO COLD POOL FORMATION/MOVEMENT SHOULD
BE THE PRIMARY DRIVER. THEREFORE...A FLASH FLOOD THREAT MAY PERSIST
AND ANOTHER FLASH FLOOD WATCH MAY BE NEEDED FOR MONDAY EVENING IN
LATER FORECAST PACKAGES.
ON TUESDAY...THE FRONT SHOULD FINALLY SLIDE ALL THE WAY THROUGH THE
REGION...RESTRICTING HIGHEST INSTABILITY SOUTH OF THE FRONT AND
PRIMARILY SOUTH OF THE REGION. HOWEVER...CONFIDENCE IS LOW ON WHEN
THIS COLD FRONT WILL SURGE SOUTH AND THERE MAY BE ENOUGH TIME FOR
STORM DEVELOPMENT AHEAD OF THE FRONT. THIS WOULD MEAN SEVERE WEATHER
IS POSSIBLE BUT UNLIKELY TUESDAY. HOWEVER...ADDITIONAL PERTURBATIONS
MOVE IN FROM THE NORTHWEST BEHIND THE MAIN FORCING AND WITH SOME
INSTABILITY REMAINING IN THE POST-FRONTAL ENVIRONMENT...THERE SHOULD
BE ADDITIONAL SHOWER/THUNDERSTORM DEVELOPMENT TUESDAY AFTERNOON BUT
COVERAGE AND INTENSITY REMAINS IN DOUBT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1138 AM MDT SUN AUG 16 2015
THUNDERSTORM ACTIVITY IS EXPECTED TO IMPACT BOTH KGLD AND KMCK
TERMINALS LATE THIS AFTERNOON THROUGH MOST OF THE TAF PERIOD. BEST
COVERAGE WILL BE DURING THE EVENING AS A SLOW MOVING CLUSTER OF
THUNDERSTORMS MOVES ACROSS THE REGION. THERE SHOULD BE A LULL IN
COVERAGE BEFORE ADDITIONAL THUNDERSTORMS DEVELOP AND MOVE
SOUTHEAST ALONG A COLD FRONT MONDAY. SOME GUIDANCE IS SHOWING
IFR CIGS AT KMCK 10-14Z...HOWEVER THIS APPEARS TO BE MORE LIKELY
TIED TO FRONTAL PASSAGE WHICH MAY NOT BE UNTIL AFTER THE CURRENT
TAF PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KSZ001>003-013-014.
CO...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR COZ090-091.
NE...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR NEZ079>081.
&&
$$
SHORT TERM...DR
LONG TERM...RRH
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
235 PM MDT SUN AUG 16 2015
.SHORT TERM...(THIS AFTERNOON THROUGH MONDAY)
ISSUED AT 235 PM MDT SUN AUG 16 2015
WV IMAGERY AND RAP ANALYSIS SHOWS RIDGE CENTERED OVER SOUTHERN
CALIFORNIA WITH AXIS EXTENDING ACROSS THE HIGH PLAINS AND INTO THE
GREAT LAKES REGION. PLUMES OF MID LEVEL MOISTURE ORIGINATING IN THE
PACIFIC ARE ROTATING AROUND THE EASTERN AND NORTHERN PERIPHERY OF THE
LARGE SCALE RIDGE INTO THE ROCKIES AND HIGH PLAINS. DIFFLUENT FLOW IS
CURRENTLY IN PLACE ACROSS THE CENTRAL ROCKIES WITH TROUGH DIGGING
INTO THE NORTHERN PLAINS. A FEW WEAKER SHORTWAVE TROUGHS ARE JUST TO
THE WEST/NORTHWEST OF OUR CWA. AT THE SURFACE QUASI-STATIONARY FRONT
CURRENTLY EXTENDS ACROSS CENTRAL NEBRASKA INTO NORTHCENTRAL COLORADO
OVER THE FAR NORTHWEST PART OF OUR CWA. PREFRONTAL TROUGH AXIS IS IN
PLACE FROM SOUTHEAST COLORADO OVER GOODLAND AND NORTON KANSAS.
THIS AFTERNOON-TONIGHT...THUNDERSTORM ACTIVITY SHOULD INITIATE
WITHIN THE NEXT FEW HOURS ALONG FRONT AND SURFACE TROUGH WITH
COVERAGE INCREASING THIS EVENING AS A SERIES OF WEAK SHORTWAVE
TROUGHS ROTATE ACROSS THE REGION. RECENT TRENDS IN ARW/NMM HAVE BEEN
TO SHIFT MOST ORGANIZED THUNDERSTORM CLUSTER TO THE SOUTH ROUGHLY
ALONG AND SOUTH OF INTERSTATE 70. CURRENTLY THE ORIENTATION OF FLOW
ALOFT AND OTHER GUIDANCE STILL SHOWING THUNDERSTORM CLUSTERS
ORIGINATING FROM THE WEST OR NORTHWEST OF THIS. EITHER WAY...DEEP
MOIST AIR MASS AND DECENT INSTABILITY AHEAD OF FRONT WILL SUPPORT
ACTIVITY ACROSS MUCH OF CWA TRANSITIONING EASTWARD. STRONGEST CAPE
AXIS IF FURTHER EAST THAN PREVIOUS GUIDANCE INDICATED...THOUGH THERE
IS ENOUGH ELEVATED CAPE TO AT LEAST CONSIDER POTENTIAL FOR
MARGINALLY SEVERE HAIL. DCAPE 1000-1500 J/KG COINCIDING DRY ADIABATIC
PROFILES BELOW 700MB COULD SUPPORT ISOLATED SEVERE DOWNDRAFT
POTENTIAL DURING THE AFTERNOON...THOUGH AS MIXING RATIOS INCREASE
BELOW 700MB THIS EVENING THIS THREAT WILL LIKELY DIMINISH.
REGARDING FLASH FLOOD WATCH...ANOMALOUSLY HIGH PWAT VALUES 1.2-1.6
WILL ONLY INCREASE THROUGH THE NIGHT APPROACHING 1.7-1.8 WHICH IS
WELL WITHIN 99TH PERCENTILE OR 3 STANDARD DEVIATIONS FROM NORMAL.
WITH VERY SLOW STORM MOTIONS AND POSSIBILITY FOR
TRAINING/BACKBUILDING I AM COMFORTABLE WITH FLASH FLOOD WATCH. IF
ARW/NMM SOLUTION PANS OUT THEN WE MAY NEED TO CONSIDER ADDING
SOUTHERN PART OF FORECAST AREA TO WATCH.
MONDAY...WHILE FRONTAL PASSAGE SHOULD OCCUR FROM NORTH TO SOUTH
MONDAY...GUIDANCE IS SHOWING A LOT OF SPREAD ON TIMING. THIS LOWERS
CONFIDENCE/TIMING OF ADDITIONAL THUNDERSTORM ACTIVITY. ARW/NMM SHOW
A MORE ORGANIZED THUNDERSTORM CLUSTER DEVELOPING ALONG FRONT MONDAY
MORNING...THOUGH OTHER GUIDANCE IS SHOWING PREDOMINANTLY ISOLATED TO
SCATTERED ACTIVITY LINGERING ACROSS THE AREA. DEEP MOIST LAYER
REMAINS IN PLACE...SO WITH POTENTIAL FOR OVERRUNNING ALONG BAROCLINIC
ZONE...IT IS POSSIBLE FOR A MORE ORGANIZED CLUSTER IF WE CONTINUE TO
SEE WEAK HEIGHT FALL...WHICH COULD ALSO RESULT CONTINUING THREAT FOR
FLASH FLOODING. SEVERE THUNDERSTORM THREAT WILL BE HIGHLY DEPENDENT
ON FRONTAL POSITION/TIMING AS BETTER INSTABILITY WILL TEND TO BE
AHEAD OF FRONT. AS WITH TODAY...THREATS WOULD BE LARGE HAIL/DAMAGING
WINDS ALONG/SOUTH OF FRONT.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 138 AM MDT SUN AUG 16 2015
THE EXTENDED FORECAST IS SHOWING TO BE MOSTLY DRY WITH THE EXCEPTION
OF SOME LINGERING SHOWERS AND STORMS WEDNESDAY AT 12Z FROM THE
TROUGH MOVING EAST OUT OF THE CWA. AFTER...THINGS WILL DRY OUT AND
THE UPPER LEVEL FLOW WILL BECOME ZONAL OVER THE MAJORITY OF THE US.
FRIDAY NIGHT IS INDICATING SOME LOW CHANCES FOR PRECIP. THERE IS AN
INFLOW OF MONSOONAL MOISTURE FROM THE DESERT SOUTHWEST...AS WELL AS
SOME DIVERGENCE ALOFT AND WEAK 700MB SHORTWAVES. HIGH PRESSURE IS
ALSO DOMINATING OVER THE MAJORITY OF THE SOUTHERN STATES. HIGH
TEMPERATURES FOR THE PERIOD WILL BE BELOW NORMAL ON
WEDNESDAY...REACHING ONLY INTO THE 70S. HIGH TEMPERATURES WILL THEN
RETURN BACK TO NORMAL BY THE END OF THE PERIOD...INCREASING INTO THE
80S AND 90S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1138 AM MDT SUN AUG 16 2015
THUNDERSTORM ACTIVITY IS EXPECTED TO IMPACT BOTH KGLD AND KMCK
TERMINALS LATE THIS AFTERNOON THROUGH MOST OF THE TAF PERIOD. BEST
COVERAGE WILL BE DURING THE EVENING AS A SLOW MOVING CLUSTER OF
THUNDERSTORMS MOVES ACROSS THE REGION. THERE SHOULD BE A LULL IN
COVERAGE BEFORE ADDITIONAL THUNDERSTORMS DEVELOP AND MOVE
SOUTHEAST ALONG A COLD FRONT MONDAY. SOME GUIDANCE IS SHOWING
IFR CIGS AT KMCK 10-14Z...HOWEVER THIS APPEARS TO BE MORE LIKELY
TIED TO FRONTAL PASSAGE WHICH MAY NOT BE UNTIL AFTER THE CURRENT
TAF PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KSZ001>003-013-014.
CO...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR COZ090-091.
NE...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR NEZ079>081.
&&
$$
SHORT TERM...DR
LONG TERM...CLT
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
139 AM MDT SUN AUG 16 2015
.UPDATE...
ISSUED AT 1046 PM MDT SAT AUG 15 2015
UPDATED FORECAST FOR THE EVENING TO ACCOUNT FOR THE AREA OF STORMS
OVER LINCOLN COUNTY. LIFT FROM AN UPPER LEVEL SHORT WAVE TROUGH
JUST WEST OF THE AREA HAS BEEN SUSTAINING THESE STORMS IN ADDITION
TO THE PRESENCE OF THE LOW LEVEL JET THERE AS WELL. IF STORMS DO
MOVE INTO CHEYENNE AND KIT CARSON COUNTIES...THEY WILL BE MOVING
INTO DRIER AIR. SINCE THESE STORMS ARE CONTINUING TO WEAKEN AM
DOUBTFUL THEY WILL MOVE VERY FAR INTO EITHER OF THOSE COUNTIES.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 244 PM MDT SAT AUG 15 2015
EARLY AFTERNOON WV IMAGERY AND RAP H5 ANALYSIS SHOWS RIDGE EXTENDING
FROM THE SOUTHERN PLAINS TO THE GREAT LAKES WITH A TROUGH ACROSS THE
PACIFIC NORTHWEST. SW FLOW IS IN PLACE ACROSS THE CENTRAL ROCKIES
AND NORTHERN PLAINS. AT THE SURFACE...SURFACE LOW PRESSURE IS IN
PLACE ACROSS EASTERN COLORADO WITH A COLD FRONT EXTENDING FROM THE
GREAT BASIN ACROSS WYOMING AND INTO WESTERN EXTENT OF NORTH DAKOTA.
THIS AFTERNOON-TONIGHT...SHORT RANGE/HI RES GUIDANCE INDICATES
THUNDERSTORM ACTIVITY INITIATING ALONG SURFACE TROUGH AND ACROSS
CHEYENNE RIDGE AND SLOWLY MOVING EASTWARD AS WEAK SHORTWAVE TROUGH
PROPAGATES THROUGH THE SOUTHERLY FLOW ACROSS THE ROCKIES. MOST
GUIDANCE IS SHOWING BETTER COVERAGE ACROSS THE NORTHWEST HALF OF THE
CWA THAT CORRELATES WITH BETTER FORCING. DEEP MOIST AIR MASS IN
PLACE...SLOWER STORM MOTIONS AND MODERATE INSTABILITY WILL SUPPORT
LOCALLY HEAVY RAINFALL WITH ANY ACTIVITY THAT DEVELOPS. CAPE VALUES
1500-3000 J/KG COULD SUPPORT A FEW STRONGER UPDRAFTS DESPITE MINIMAL
SHEER...WITH LARGE HAIL/ISOLATED DOWN DRAFTS MAIN SEVERE
THUNDERSTORM THREATS.
SUNDAY...UPPER LOW OVER THE PACIFIC NORTHWEST SHIFTS EAST WITH
FALLING HEIGHTS THROUGH THE AFTERNOON. COLD FRONT WILL BE AT LEAST
APPROACHING THE REGION BY THE AFTERNOON...WITH FASTER GUIDANCE
SHOWING FROPA BY MIDDAY. INCREASING FORCING AND DEEP MOISTURE WILL
SUPPORT INCREASING SHOWER/THUNDERSTORM COVERAGE. MODERATE
CAPE...INCREASING EFFECTIVE SHEER WILL COINCIDE IN BETTER CHANCE FOR
SEVERE THUNDERSTORMS BY THE LATE AFTERNOON PERIOD.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 138 AM MDT SUN AUG 16 2015
THE EXTENDED FORECAST IS SHOWING TO BE MOSTLY DRY WITH THE EXCEPTION
OF SOME LINGERING SHOWERS AND STORMS WEDNESDAY AT 12Z FROM THE
TROUGH MOVING EAST OUT OF THE CWA. AFTER...THINGS WILL DRY OUT AND
THE UPPER LEVEL FLOW WILL BECOME ZONAL OVER THE MAJORITY OF THE US.
FRIDAY NIGHT IS INDICATING SOME LOW CHANCES FOR PRECIP. THERE IS AN
INFLOW OF MONSOONAL MOISTURE FROM THE DESERT SOUTHWEST...AS WELL AS
SOME DIVERGENCE ALOFT AND WEAK 700MB SHORTWAVES. HIGH PRESSURE IS
ALSO DOMINATING OVER THE MAJORITY OF THE SOUTHERN STATES. HIGH
TEMPERATURES FOR THE PERIOD WILL BE BELOW NORMAL ON
WEDNESDAY...REACHING ONLY INTO THE 70S. HIGH TEMPERATURES WILL THEN
RETURN BACK TO NORMAL BY THE END OF THE PERIOD...INCREASING INTO THE
80S AND 90S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1118 PM MDT SAT AUG 15 2015
VFR CONDITIONS FORECAST FOR THE 6Z TAFS. MAIN FOCUS FOR THE TAFS
WILL BE THE CHANCES FOR STORMS DURING THE AFTERNOON AND EVENING
FOR BOTH SITES. CURRENTLY LOOKS LIKE STORMS WILL BEGIN TO FORM IN
THE EARLY AFTERNOON...WITH COVERAGE PEAKING BY LATE AFTERNOON AND
POSSIBLY LASTING INTO THE OVERNIGHT HOURS. LOOKS LIKE THERE WILL
BE MULTIPLE ROUNDS OF STORMS DURING THIS TIME SO DIFFICULT TO
DETERMINE WHEN ONE WAVE WILL START AND ANOTHER WILL END. DOES LOOK
LIKE THE MAIN THREAT WILL BE HEAVY RAINFALL...ALTHOUGH LARGE HAIL
AND SEVERE WINDS CANNOT BE RULED OUT. IF HEAVY RAINFALL DOES MOVE
OVER A SITE...EXPECT VISIBILITIES TO FALL TO MVFR OR POSSIBLY
LOWER.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JTL
SHORT TERM...DR
LONG TERM...CLT
AVIATION...JTL
AREA FORECAST DISCUSSION
NWS GOODLAND KS
132 AM MDT SUN AUG 16 2015
.UPDATE...
ISSUED AT 1046 PM MDT SAT AUG 15 2015
UPDATED FORECAST FOR THE EVENING TO ACCOUNT FOR THE AREA OF STORMS
OVER LINCOLN COUNTY. LIFT FROM AN UPPER LEVEL SHORT WAVE TROUGH
JUST WEST OF THE AREA HAS BEEN SUSTAINING THESE STORMS IN ADDITION
TO THE PRESENCE OF THE LOW LEVEL JET THERE AS WELL. IF STORMS DO
MOVE INTO CHEYENNE AND KIT CARSON COUNTIES...THEY WILL BE MOVING
INTO DRIER AIR. SINCE THESE STORMS ARE CONTINUING TO WEAKEN AM
DOUBTFUL THEY WILL MOVE VERY FAR INTO EITHER OF THOSE COUNTIES.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 244 PM MDT SAT AUG 15 2015
EARLY AFTERNOON WV IMAGERY AND RAP H5 ANALYSIS SHOWS RIDGE EXTENDING
FROM THE SOUTHERN PLAINS TO THE GREAT LAKES WITH A TROUGH ACROSS THE
PACIFIC NORTHWEST. SW FLOW IS IN PLACE ACROSS THE CENTRAL ROCKIES
AND NORTHERN PLAINS. AT THE SURFACE...SURFACE LOW PRESSURE IS IN
PLACE ACROSS EASTERN COLORADO WITH A COLD FRONT EXTENDING FROM THE
GREAT BASIN ACROSS WYOMING AND INTO WESTERN EXTENT OF NORTH DAKOTA.
THIS AFTERNOON-TONIGHT...SHORT RANGE/HI RES GUIDANCE INDICATES
THUNDERSTORM ACTIVITY INITIATING ALONG SURFACE TROUGH AND ACROSS
CHEYENNE RIDGE AND SLOWLY MOVING EASTWARD AS WEAK SHORTWAVE TROUGH
PROPAGATES THROUGH THE SOUTHERLY FLOW ACROSS THE ROCKIES. MOST
GUIDANCE IS SHOWING BETTER COVERAGE ACROSS THE NORTHWEST HALF OF THE
CWA THAT CORRELATES WITH BETTER FORCING. DEEP MOIST AIR MASS IN
PLACE...SLOWER STORM MOTIONS AND MODERATE INSTABILITY WILL SUPPORT
LOCALLY HEAVY RAINFALL WITH ANY ACTIVITY THAT DEVELOPS. CAPE VALUES
1500-3000 J/KG COULD SUPPORT A FEW STRONGER UPDRAFTS DESPITE MINIMAL
SHEER...WITH LARGE HAIL/ISOLATED DOWN DRAFTS MAIN SEVERE
THUNDERSTORM THREATS.
SUNDAY...UPPER LOW OVER THE PACIFIC NORTHWEST SHIFTS EAST WITH
FALLING HEIGHTS THROUGH THE AFTERNOON. COLD FRONT WILL BE AT LEAST
APPROACHING THE REGION BY THE AFTERNOON...WITH FASTER GUIDANCE
SHOWING FROPA BY MIDDAY. INCREASING FORCING AND DEEP MOISTURE WILL
SUPPORT INCREASING SHOWER/THUNDERSTORM COVERAGE. MODERATE
CAPE...INCREASING EFFECTIVE SHEER WILL COINCIDE IN BETTER CHANCE FOR
SEVERE THUNDERSTORMS BY THE LATE AFTERNOON PERIOD.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 129 AM MDT SUN AUG 16 2015
THE EXTENDED FORECAST IS SHOWING TO BE MOSTLY DRY WITH THE EXCEPTION
OF SOME LINGERING SHOWERS AND STORMS WEDNESDAY AT 12Z FROM THE
TROUGH MOVING EAST OUT OF THE CWA. AFTER...THINGS WILL DRY OUT AND
THE UPPER LEVEL FLOW WILL BECOME ZONAL OVER THE MAJORITY OF THE US.
FRIDAY NIGHT IS INDICATING SOME LOW CHANCES FOR PRECIP. THERE IS AN
INFLOW OF MONSOONAL MOISTURE FROM THE DESERT SOUTHWEST...AS WELL AS
SOME DIVERGENCE ALOFT AND WEAK 700MB SHORTWAVES. HIGH PRESSURE IS
ALSO DOMINATING OVER THE MAJORITY OF THE SOUTHERN STATES. HIGH
TEMPERATURES FOR THE PERIOD WILL BE IN BELOW NORMAL ON WEDNESDAY IN
THE 70S AND THEN RETURN BACK TO NORMAL IN THE 80S TO 90S BY THE END
OF THE PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1118 PM MDT SAT AUG 15 2015
VFR CONDITIONS FORECAST FOR THE 6Z TAFS. MAIN FOCUS FOR THE TAFS
WILL BE THE CHANCES FOR STORMS DURING THE AFTERNOON AND EVENING
FOR BOTH SITES. CURRENTLY LOOKS LIKE STORMS WILL BEGIN TO FORM IN
THE EARLY AFTERNOON...WITH COVERAGE PEAKING BY LATE AFTERNOON AND
POSSIBLY LASTING INTO THE OVERNIGHT HOURS. LOOKS LIKE THERE WILL
BE MULTIPLE ROUNDS OF STORMS DURING THIS TIME SO DIFFICULT TO
DETERMINE WHEN ONE WAVE WILL START AND ANOTHER WILL END. DOES LOOK
LIKE THE MAIN THREAT WILL BE HEAVY RAINFALL...ALTHOUGH LARGE HAIL
AND SEVERE WINDS CANNOT BE RULED OUT. IF HEAVY RAINFALL DOES MOVE
OVER A SITE...EXPECT VISIBILITIES TO FALL TO MVFR OR POSSIBLY
LOWER.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JTL
SHORT TERM...DR
LONG TERM...CLT
AVIATION...JTL
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1124 PM MDT SAT AUG 15 2015
.UPDATE...
ISSUED AT 1046 PM MDT SAT AUG 15 2015
UPDATED FORECAST FOR THE EVENING TO ACCOUNT FOR THE AREA OF STORMS
OVER LINCOLN COUNTY. LIFT FROM AN UPPER LEVEL SHORT WAVE TROUGH
JUST WEST OF THE AREA HAS BEEN SUSTAINING THESE STORMS IN ADDITION
TO THE PRESENCE OF THE LOW LEVEL JET THERE AS WELL. IF STORMS DO
MOVE INTO CHEYENNE AND KIT CARSON COUNTIES...THEY WILL BE MOVING
INTO DRIER AIR. SINCE THESE STORMS ARE CONTINUING TO WEAKEN AM
DOUBTFUL THEY WILL MOVE VERY FAR INTO EITHER OF THOSE COUNTIES.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 244 PM MDT SAT AUG 15 2015
EARLY AFTERNOON WV IMAGERY AND RAP H5 ANALYSIS SHOWS RIDGE EXTENDING
FROM THE SOUTHERN PLAINS TO THE GREAT LAKES WITH A TROUGH ACROSS THE
PACIFIC NORTHWEST. SW FLOW IS IN PLACE ACROSS THE CENTRAL ROCKIES
AND NORTHERN PLAINS. AT THE SURFACE...SURFACE LOW PRESSURE IS IN
PLACE ACROSS EASTERN COLORADO WITH A COLD FRONT EXTENDING FROM THE
GREAT BASIN ACROSS WYOMING AND INTO WESTERN EXTENT OF NORTH DAKOTA.
THIS AFTERNOON-TONIGHT...SHORT RANGE/HI RES GUIDANCE INDICATES
THUNDERSTORM ACTIVITY INITIATING ALONG SURFACE TROUGH AND ACROSS
CHEYENNE RIDGE AND SLOWLY MOVING EASTWARD AS WEAK SHORTWAVE TROUGH
PROPAGATES THROUGH THE SOUTHERLY FLOW ACROSS THE ROCKIES. MOST
GUIDANCE IS SHOWING BETTER COVERAGE ACROSS THE NORTHWEST HALF OF THE
CWA THAT CORRELATES WITH BETTER FORCING. DEEP MOIST AIR MASS IN
PLACE...SLOWER STORM MOTIONS AND MODERATE INSTABILITY WILL SUPPORT
LOCALLY HEAVY RAINFALL WITH ANY ACTIVITY THAT DEVELOPS. CAPE VALUES
1500-3000 J/KG COULD SUPPORT A FEW STRONGER UPDRAFTS DESPITE MINIMAL
SHEER...WITH LARGE HAIL/ISOLATED DOWN DRAFTS MAIN SEVERE
THUNDERSTORM THREATS.
SUNDAY...UPPER LOW OVER THE PACIFIC NORTHWEST SHIFTS EAST WITH
FALLING HEIGHTS THROUGH THE AFTERNOON. COLD FRONT WILL BE AT LEAST
APPROACHING THE REGION BY THE AFTERNOON...WITH FASTER GUIDANCE
SHOWING FROPA BY MIDDAY. INCREASING FORCING AND DEEP MOISTURE WILL
SUPPORT INCREASING SHOWER/THUNDERSTORM COVERAGE. MODERATE
CAPE...INCREASING EFFECTIVE SHEER WILL COINCIDE IN BETTER CHANCE FOR
SEVERE THUNDERSTORMS BY THE LATE AFTERNOON PERIOD.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 342 PM MDT SAT AUG 15 2015
FOR THE EXTENDED FORECAST PERIOD...BIG CHANGES ARE ON THE WAY IN
TERMS OF COOLER TEMPERATURES AND LESS HUMIDITY AFTER A TUESDAY COLD
FRONT PASSAGE. AHEAD OF THE COLD FRONT...A PERIOD OF STORMS APPEARS
LIKELY FROM SUNDAY NIGHT THROUGH TUESDAY AS UPPER LEVEL DISTURBANCES
EJECT ACROSS THE HIGH PLAINS.
BEGINNING WITH SUNDAY NIGHT...WIDESPREAD THUNDERSTORM ACTIVITY IS
EXPECTED. STORMS INITIALLY DEVELOP ALONG A SLOW MOVING FRONTAL
BOUNDARY BEFORE CRAWLING EAST THROUGH SUNDAY EVENING. SLOW STORM
MOTIONS...AT OR BELOW 10 KNOTS...MODERATE INSTABILITY AND
PRECIPITABLE WATER VALUES NEAR 1.80 INCHES INDICATE A FLASH FLOOD
THREAT...ESPECIALLY FOR STORMS THAT TRAIN. SHEAR PARAMETERS ARE NOT
OVERLY IMPRESSIVE BUT SHOULD BE SUFFICIENT FOR ORGANIZED
THUNDERSTORM ACTIVITY. LARGE HAIL AND DAMAGING WINDS APPEAR TO BE
THE PRIMARY SEVERE PARAMETERS BUT FLASH FLOODING MAY BE THE MORE
SIGNIFICANT THREAT TO MONITOR.
ON MONDAY...ANOTHER LEAD SHORTWAVE TROUGH AHEAD OF A MORE
SUBSTANTIAL LONGWAVE TROUGH EJECTS TO CONTINUE THE STORMY PATTERN.
INSTABILITY BUILDS UP ONCE AGAIN BUT WIND SHEAR IS MORE SUBSTANTIAL
MONDAY. HOWEVER...THERE MAY BE STRATUS AND FOG MONDAY MORNING WITH A
STALLED FRONT IN THE REGION. THIS WOULD LEAD TO A MORE STABLE
ATMOSPHERE DEPENDING ON AMOUNT OF SUNLIGHT RECEIVED. A LITTLE UNSURE
ON HOW SUBSTANTIAL A SEVERE THREAT WOULD DEVELOP BECAUSE OF
FOG/STRATUS AND CONVECTIVE OVERTURNING. THE STORM PREDICTION CENTER
HAS ISSUED A SLIGHT RISK FOR SEVERE WEATHER ON MONDAY AND AGREE WITH
THEIR ASSESSMENT. AS FOR HEAVY RAINFALL POTENTIAL...PRECIPITABLE
WATER VALUES ARE LOWER THAN SUNDAY EVENING. HOWEVER...SLOW STORM
MOTIONS SHOULD CONTRIBUTE TO AT LEAST SOME HEAVY RAINFALL THREAT.
DEPENDING ON PRECIPITATION RECEIVED SUNDAY EVENING...FLASH FLOODING
MAY BECOME MORE LIKELY IF SOILS ARE SATURATED.
TUESDAY...THE PRIMARY DISTURBANCE WILL PUSH THROUGH...FORCING THE
FRONT COMPLETELY THROUGH THE REGION. THE QUESTION OF TIMING REMAINS
BUT A LATER EJECTION...AS SHOWN WITH LATEST EUROPEAN AND CANADIAN
GUIDANCE...WOULD FAVOR A MORE SUBSTANTIAL SEVERE WEATHER THREAT ONCE
AGAIN. BEHIND THIS FRONT...ANTICIPATE NOTICEABLY COOLER TEMPERATURES
AND LOWERED RELATIVE HUMIDITY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1118 PM MDT SAT AUG 15 2015
VFR CONDITIONS FORECAST FOR THE 6Z TAFS. MAIN FOCUS FOR THE TAFS
WILL BE THE CHANCES FOR STORMS DURING THE AFTERNOON AND EVENING
FOR BOTH SITES. CURRENTLY LOOKS LIKE STORMS WILL BEGIN TO FORM IN
THE EARLY AFTERNOON...WITH COVERAGE PEAKING BY LATE AFTERNOON AND
POSSIBLY LASTING INTO THE OVERNIGHT HOURS. LOOKS LIKE THERE WILL
BE MULTIPLE ROUNDS OF STORMS DURING THIS TIME SO DIFFICULT TO
DETERMINE WHEN ONE WAVE WILL START AND ANOTHER WILL END. DOES LOOK
LIKE THE MAIN THREAT WILL BE HEAVY RAINFALL...ALTHOUGH LARGE HAIL
AND SEVERE WINDS CANNOT BE RULED OUT. IF HEAVY RAINFALL DOES MOVE
OVER A SITE...EXPECT VISIBILITIES TO FALL TO MVFR OR POSSIBLY
LOWER.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JTL
SHORT TERM...DR
LONG TERM...RRH
AVIATION...JTL
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1051 PM MDT SAT AUG 15 2015
.UPDATE...
ISSUED AT 1046 PM MDT SAT AUG 15 2015
UPDATED FORECAST FOR THE EVENING TO ACCOUNT FOR THE AREA OF STORMS
OVER LINCOLN COUNTY. LIFT FROM AN UPPER LEVEL SHORT WAVE TROUGH
JUST WEST OF THE AREA HAS BEEN SUSTAINING THESE STORMS IN ADDITION
TO THE PRESENCE OF THE LOW LEVEL JET THERE AS WELL. IF STORMS DO
MOVE INTO CHEYENNE AND KIT CARSON COUNTIES...THEY WILL BE MOVING
INTO DRIER AIR. SINCE THESE STORMS ARE CONTINUING TO WEAKEN AM
DOUBTFUL THEY WILL MOVE VERY FAR INTO EITHER OF THOSE COUNTIES.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 244 PM MDT SAT AUG 15 2015
EARLY AFTERNOON WV IMAGERY AND RAP H5 ANALYSIS SHOWS RIDGE EXTENDING
FROM THE SOUTHERN PLAINS TO THE GREAT LAKES WITH A TROUGH ACROSS THE
PACIFIC NORTHWEST. SW FLOW IS IN PLACE ACROSS THE CENTRAL ROCKIES
AND NORTHERN PLAINS. AT THE SURFACE...SURFACE LOW PRESSURE IS IN
PLACE ACROSS EASTERN COLORADO WITH A COLD FRONT EXTENDING FROM THE
GREAT BASIN ACROSS WYOMING AND INTO WESTERN EXTENT OF NORTH DAKOTA.
THIS AFTERNOON-TONIGHT...SHORT RANGE/HI RES GUIDANCE INDICATES
THUNDERSTORM ACTIVITY INITIATING ALONG SURFACE TROUGH AND ACROSS
CHEYENNE RIDGE AND SLOWLY MOVING EASTWARD AS WEAK SHORTWAVE TROUGH
PROPAGATES THROUGH THE SOUTHERLY FLOW ACROSS THE ROCKIES. MOST
GUIDANCE IS SHOWING BETTER COVERAGE ACROSS THE NORTHWEST HALF OF THE
CWA THAT CORRELATES WITH BETTER FORCING. DEEP MOIST AIR MASS IN
PLACE...SLOWER STORM MOTIONS AND MODERATE INSTABILITY WILL SUPPORT
LOCALLY HEAVY RAINFALL WITH ANY ACTIVITY THAT DEVELOPS. CAPE VALUES
1500-3000 J/KG COULD SUPPORT A FEW STRONGER UPDRAFTS DESPITE MINIMAL
SHEER...WITH LARGE HAIL/ISOLATED DOWN DRAFTS MAIN SEVERE
THUNDERSTORM THREATS.
SUNDAY...UPPER LOW OVER THE PACIFIC NORTHWEST SHIFTS EAST WITH
FALLING HEIGHTS THROUGH THE AFTERNOON. COLD FRONT WILL BE AT LEAST
APPROACHING THE REGION BY THE AFTERNOON...WITH FASTER GUIDANCE
SHOWING FROPA BY MIDDAY. INCREASING FORCING AND DEEP MOISTURE WILL
SUPPORT INCREASING SHOWER/THUNDERSTORM COVERAGE. MODERATE
CAPE...INCREASING EFFECTIVE SHEER WILL COINCIDE IN BETTER CHANCE FOR
SEVERE THUNDERSTORMS BY THE LATE AFTERNOON PERIOD.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 342 PM MDT SAT AUG 15 2015
FOR THE EXTENDED FORECAST PERIOD...BIG CHANGES ARE ON THE WAY IN
TERMS OF COOLER TEMPERATURES AND LESS HUMIDITY AFTER A TUESDAY COLD
FRONT PASSAGE. AHEAD OF THE COLD FRONT...A PERIOD OF STORMS APPEARS
LIKELY FROM SUNDAY NIGHT THROUGH TUESDAY AS UPPER LEVEL DISTURBANCES
EJECT ACROSS THE HIGH PLAINS.
BEGINNING WITH SUNDAY NIGHT...WIDESPREAD THUNDERSTORM ACTIVITY IS
EXPECTED. STORMS INITIALLY DEVELOP ALONG A SLOW MOVING FRONTAL
BOUNDARY BEFORE CRAWLING EAST THROUGH SUNDAY EVENING. SLOW STORM
MOTIONS...AT OR BELOW 10 KNOTS...MODERATE INSTABILITY AND
PRECIPITABLE WATER VALUES NEAR 1.80 INCHES INDICATE A FLASH FLOOD
THREAT...ESPECIALLY FOR STORMS THAT TRAIN. SHEAR PARAMETERS ARE NOT
OVERLY IMPRESSIVE BUT SHOULD BE SUFFICIENT FOR ORGANIZED
THUNDERSTORM ACTIVITY. LARGE HAIL AND DAMAGING WINDS APPEAR TO BE
THE PRIMARY SEVERE PARAMETERS BUT FLASH FLOODING MAY BE THE MORE
SIGNIFICANT THREAT TO MONITOR.
ON MONDAY...ANOTHER LEAD SHORTWAVE TROUGH AHEAD OF A MORE
SUBSTANTIAL LONGWAVE TROUGH EJECTS TO CONTINUE THE STORMY PATTERN.
INSTABILITY BUILDS UP ONCE AGAIN BUT WIND SHEAR IS MORE SUBSTANTIAL
MONDAY. HOWEVER...THERE MAY BE STRATUS AND FOG MONDAY MORNING WITH A
STALLED FRONT IN THE REGION. THIS WOULD LEAD TO A MORE STABLE
ATMOSPHERE DEPENDING ON AMOUNT OF SUNLIGHT RECEIVED. A LITTLE UNSURE
ON HOW SUBSTANTIAL A SEVERE THREAT WOULD DEVELOP BECAUSE OF
FOG/STRATUS AND CONVECTIVE OVERTURNING. THE STORM PREDICTION CENTER
HAS ISSUED A SLIGHT RISK FOR SEVERE WEATHER ON MONDAY AND AGREE WITH
THEIR ASSESSMENT. AS FOR HEAVY RAINFALL POTENTIAL...PRECIPITABLE
WATER VALUES ARE LOWER THAN SUNDAY EVENING. HOWEVER...SLOW STORM
MOTIONS SHOULD CONTRIBUTE TO AT LEAST SOME HEAVY RAINFALL THREAT.
DEPENDING ON PRECIPITATION RECEIVED SUNDAY EVENING...FLASH FLOODING
MAY BECOME MORE LIKELY IF SOILS ARE SATURATED.
TUESDAY...THE PRIMARY DISTURBANCE WILL PUSH THROUGH...FORCING THE
FRONT COMPLETELY THROUGH THE REGION. THE QUESTION OF TIMING REMAINS
BUT A LATER EJECTION...AS SHOWN WITH LATEST EUROPEAN AND CANADIAN
GUIDANCE...WOULD FAVOR A MORE SUBSTANTIAL SEVERE WEATHER THREAT ONCE
AGAIN. BEHIND THIS FRONT...ANTICIPATE NOTICEABLY COOLER TEMPERATURES
AND LOWERED RELATIVE HUMIDITY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 528 PM MDT SAT AUG 15 2015
VFR CONDITIONS FORECAST FOR THE 0Z TAFS. BREEZY WINDS FROM THIS
AFTERNOON WILL CONTINUE THROUGH THE MAJORITY OF THE EVENING BEFORE
DECREASING. OVERNIGHT THERE COULD BE A SLIGHT REDUCTION IN
VISIBILITY AT KGLD DUE TO THE MOISTURE ADVECTION AND TEMPERATURES
COOLING TO THE DEW POINT. HOWEVER CLIMATOLOGY DOES NOT FAVOR MUCH
IF ANY FOG DEVELOPING AND THE SOUTH WINDS SHOULD BE STRONG ENOUGH
TO PREVENT MUCH OF A VISIBILITY REDUCTION. WINDS WILL TURN TO THE
SOUTHWEST FOR A FEW HOURS IN THE MORNING THEN TURN BACK TO THE
SOUTH AGAIN.
DURING THE AFTERNOON STORMS WILL DEVELOP OVER THE AREA. THESE
STORMS WILL BE MOVING VERY SLOW AND WILL BE CAPABLE OF PRODUCING
HEAVY RAINFALL...WHICH WILL CAUSE REDUCTIONS IN VISIBILITY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JTL
SHORT TERM...DR
LONG TERM...RRH
AVIATION...JTL
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
950 PM EDT MON AUG 17 2015
.SYNOPSIS...
WARM...HUMID...AND UNSETTLED WEATHER IS EXPECTED THROUGH MUCH OF
THE WEEK UNTIL THE PASSAGE OF A COLD FRONT THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
WITH 945PM UPDATE...MADE ADDITIONAL CHANGES TO HOURLY TEMPERATURE
TRENDS. ALSO MADE CHANGES TO HOURLY PRECIPITATION TRENDS INTO THE
EARLY MORNING HOURS...KEEPING CONDITIONS DRIER IN THE EVENING.
ALTHOUGH WIDESPREAD RAIN HAS STAYED OUT OF THE FORECAST AREA SO
FAR...SHOWERS STILL REMAIN ACROSS CENTRAL OHIO AND WEST VIRGINIA.
LATEST RUNS OF THE RAP/HRRR ARE INDECISIVE WITH WHERE UPPER LEVEL
SHORTWAVE AND ASSOCIATED SHOWERS WILL MOVE OVERNIGHT. RAP MOVES
SHOWERS NORTH INTO OHIO...WHILE THE HRRR SHIFTS SHOWERS INTO THE
NORTHERN WEST VIRGINIA PANHANDLE AND WESTERN PENNSYLVANIA.
CONSIDERING THE UNCERTAINTY AND THE HIGH CHANCE POPS ALREADY IN
THE FORECAST...WILL MAKE LITTLE CHANGE OVERNIGHT. HAVE ALSO
MAINTAINED SLIGHT CHANCE THUNDER MENTION CONSIDERING THIN ELEVATED
CAPE SHOWN OVERNIGHT ON BUFKIT SOUNDINGS.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
DEEPENING UPPER TROUGH AND STRENGTHENING SURFACE LOW OVER THE
NORTHERN PLAINS WILL CONTINUE THE FEED WARMTH AND MOISTURE IN
SOUTHWEST FLOW UNTIL A COLD FRONT APPROACHES ON THURSDAY.
THUS...WHILE THE UPPER SHORTWAVE ON TUESDAY WILL BE DEPARTING TO
THE EAST...WILL KEEP A CHANCE FOR SHOWERS AND THUNDERSTORMS
THROUGH THE AFTERNOON AND ADDITIONAL CHANCES ON WEDNESDAY WITH YET
ANOTHER SHORTWAVE. WARM AIR ALOFT SHOULD HOLD MOST STORMS BELOW
SEVERE LEVELS UNTIL THE COLD FRONT APPROACHES.
LATEST MODEL GUIDANCE DIFFERS WITH THE TIMING OF THE FRONTAL
PASSAGE ON THURSDAY WHICH WOULD HAVE IMPLICATIONS ON THE STRENGTH
OF ANY CONVECTION OUT AHEAD OF IT. REGARDLESS...LATE WEDNESDAY AND
THURSDAY LOOK TO BE THE BETTER DAYS FOR INSTABILITY AND
SHEAR...WHICH PROMPTED A MARGINAL RISK FOR SEVERE OVER OUR OHIO
ZONES...CLOSER TO THE UPPER LEVEL JET. WILL CONTINUE TO MONITOR
THIS RISK AS THE FRONT APPROACHES.
TEMPERATURES SHOULD STAY CLOSE TO SEASONAL AVERAGES THROUGH THE
PERIOD.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
COLD FRONT PASSAGE IS PROGGED FOR LATE THURSDAY AND AFTER THIS
TIME MORE SEASONABLE CONDITIONS ARE ANTICIPATED. LATEST GUIDANCE
THEN KEEPS THE REGION DRY THROUGH THE REMAINDER OF THE LONG TERM.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
A CLOSED UPPER LEVEL LOW ACROSS THE LOWER OHIO VALLEY WILL SHEAR
OUT TO THE NORTHEAST THROUGH THE DAY TUESDAY. WITH WEAKENING
UPPER LEVEL SUPPORT AND SUNSET ISOLATED SHOWERS AND STORMS WILL
DISSIPATE WITH NO MENTION IN PORTS. AREA OF LIGHT RAIN AND
ISOLATED CONVECTION ON RADAR ACROSS SOUTHERN OHIO AND KY IS
WEAKENING AS THE EVENING PROGRESSES. SO ONLY MVFR FOG EXPECT
OVERNIGHT WITH A SPRINKLE OR TWO POSSIBLE.
WHAT IS LEFT OF UPPER LEVEL TROUGH WILL CROSS REGION TUESDAY WITH
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS...MAINLY LATER IN THE
AFTERNOON. BEST COVERAGE FOR NOW EXPECTED LATE DAY BUT STILL NOT
ENOUGH TO WARRANT MENTION IN TAFS. WINDS WILL BE VARIABLE UNDER 5
KTS OVERNIGHT...BECOMING SOUTH AROUND 5 KTS TUESDAY.
OUTLOOK...TUESDAY NIGHT THROUGH SATURDAY...
THE NEXT CHANCE FOR GENERAL RESTRICTIONS IS EXPECTED WITH A LATE
WEDNESDAY/THURSDAY COLD FRONT APPROACH AND PASSAGE.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
733 PM EDT MON AUG 17 2015
.SYNOPSIS...
WARM...HUMID...AND UNSETTLED WEATHER IS EXPECTED THROUGH MUCH OF
THE WEEK UNTIL THE PASSAGE OF A COLD FRONT THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
WITH 615PM UPDATE...ADJUSTED HOURLY TEMPERATURE TRENDS AS TEMPS
HAVE STAYED UP A FEW DEGREES DESPITE DIURNAL CU. ALSO ADJUSTED SKY
COVER AS OVERCAST MID LEVEL CLOUDS ARE GENERALLY WEST OF THE
FORECAST AREA AND DIURNAL CUMULUS IS ALREADY STARTING TO
DISSIPATE. 18Z NAM/GFS HAVE STARTED COMING IN THE DIRECTION OF THE
HRRR...WHICH WAS PREVIOUSLY NOTED AS HAVING GREATER PRECIPITATION
COVERAGE. HAVE NOT MADE ANY ADJUSTMENTS TO THAT PORTION OF THE
FORECAST YET...BUT WILL CONTINUE TO MONITOR UPSTREAM PRECIPITATION
TRENDS. PREVIOUS DISCUSSION FOLLOWS.
VERY SMALL ADJUSTMENTS MADE TO THE FORECAST THROUGH THE AFTERNOON
AS LOW PRESSURE...APPARENT IN VISIBLE AND WV SATELLITE IMAGERY
OVER ILLINOIS...GETS ABSORBED IN THE UPPER LEVEL FLOW. WHILE LOW
LEVEL MOISTURE WILL INCREASE AHEAD OF THIS APPROACHING WAVE...WARM
AIR ALOFT AND LITTLE SUPPORT FOR LIFT SHOULD KEEP MUCH OF THE
FORECAST AREA DRY TODAY...SAVE FOR SOME CONVECTION OVER THE HIGHER
TERRAIN AND WITH THE LAKE BREEZE. WITH THIS IN MIND...LOW CHANCE
POPS WERE MAINTAINED. WEAK SHEAR WILL KEEP ANY STORMS BELOW SEVERE
THRESHOLDS.
THE AFOREMENTIONED SHORTWAVE WILL PIVOT ACROSS THE UPPER OHIO
VALLEY OVERNIGHT. WHILE WE WILL LOSE MOST OF THE
INSTABILITY...THIN ELEVATED CAPE OVERNIGHT ON THE BUFKIT SOUNDINGS
WARRANTED AT LEAST A SLIGHT CHANCE THUNDER MENTION. THE HRRR IS
MOST AGGRESSIVE WITH THE PRECIPITATION COVERAGE VERSUS THE OTHER
HI RES MODELS OVERNIGHT. CONSIDERING THE LACK OF UPPER LEVEL JET
SUPPORT...WILL KEEP POPS IN THE CHANCE CATEGORY BUT ADJUST TIMING
CLOSE TO THE HRRR. LINGERING CLOUD COVER SHOULD KEEP TEMPERATURES
ELEVATED OVERNIGHT.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
DEEPENING UPPER TROUGH AND STRENGTHENING SURFACE LOW OVER THE
NORTHERN PLAINS WILL CONTINUE THE FEED WARMTH AND MOISTURE IN
SOUTHWEST FLOW UNTIL A COLD FRONT APPROACHES ON THURSDAY.
THUS...WHILE THE UPPER SHORTWAVE ON TUESDAY WILL BE DEPARTING TO
THE EAST...WILL KEEP A CHANCE FOR SHOWERS AND THUNDERSTORMS
THROUGH THE AFTERNOON AND ADDITIONAL CHANCES ON WEDNESDAY WITH YET
ANOTHER SHORTWAVE. WARM AIR ALOFT SHOULD HOLD MOST STORMS BELOW
SEVERE LEVELS UNTIL THE COLD FRONT APPROACHES.
LATEST MODEL GUIDANCE DIFFERS WITH THE TIMING OF THE FRONTAL
PASSAGE ON THURSDAY WHICH WOULD HAVE IMPLICATIONS ON THE STRENGTH
OF ANY CONVECTION OUT AHEAD OF IT. REGARDLESS...LATE WEDNESDAY AND
THURSDAY LOOK TO BE THE BETTER DAYS FOR INSTABILITY AND
SHEAR...WHICH PROMPTED A MARGINAL RISK FOR SEVERE OVER OUR OHIO
ZONES...CLOSER TO THE UPPER LEVEL JET. WILL CONTINUE TO MONITOR
THIS RISK AS THE FRONT APPROACHES.
TEMPERATURES SHOULD STAY CLOSE TO SEASONAL AVERAGES THROUGH THE
PERIOD.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
COLD FRONT PASSAGE IS PROGGED FOR LATE THURSDAY AND AFTER THIS
TIME MORE SEASONABLE CONDITIONS ARE ANTICIPATED. LATEST GUIDANCE
THEN KEEPS THE REGION DRY THROUGH THE REMAINDER OF THE LONG TERM.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
A CLOSED UPPER LEVEL LOW ACROSS THE LOWER OHIO VALLEY WILL SHEAR
OUT TO THE NORTHEAST THROUGH THE DAY TUESDAY. WITH WEAKENING
UPPER LEVEL SUPPORT AND SUNSET ISOLATED SHOWERS AND STORMS WILL
DISSIPATE WITH NO MENTION IN PORTS. AREA OF LIGHT RAIN AND
ISOLATED CONVECTION ON RADAR ACROSS SOUTHERN OHIO AND KY IS
WEAKENING AS THE EVENING PROGRESSES. SO ONLY MVFR FOG EXPECT
OVERNIGHT WITH A SPRINKLE OR TWO POSSIBLE.
WHAT IS LEFT OF UPPER LEVEL TROUGH WILL CROSS REGION TUESDAY WITH
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS...MAINLY LATER IN THE
AFTERNOON. BEST COVERAGE FOR NOW EXPECTED LATE DAY BUT STILL NOT
ENOUGH TO WARRANT MENTION IN TAFS. WINDS WILL BE VARIABLE UNDER 5
KTS OVERNIGHT...BECOMING SOUTH AROUND 5 KTS TUESDAY.
OUTLOOK...TUESDAY NIGHT THROUGH SATURDAY...
THE NEXT CHANCE FOR GENERAL RESTRICTIONS IS EXPECTED WITH A LATE
WEDNESDAY/THURSDAY COLD FRONT APPROACH AND PASSAGE.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
948 AM EDT SUN AUG 16 2015
.SYNOPSIS...
HIGH PRESSURE WILL GRADUALLY SLIDE EASTWARD AWAY FROM THE REGION
OVER THE NEXT FEW DAYS BUT WILL RETAIN OVERALL CONTROL THROUGH
MIDWEEK. A COLD FRONT MAY APPROACH THE AREA FROM THE NORTHWEST
LATE IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SFC HIGH PRESSURE REMAINS OVER THE AREA THIS MORNING. ALOFT...A
WEAK TROUGH AXIS EXTENDS ALONG THE EASTERN SEABOARD...ATTACHING TO
A CLOSED LOW OVER THE LOWER OHIO VALLEY.
WEATHER PATTERN REMAINS STAGNANT...SO OVERALL EXPECT SIMILAR
CONDITIONS TO SATURDAY. ANOTHER DAY OF LIGHT RETURN FLOW WILL
RESULT IN DEW POINTS AND TEMPS A DEGREE OR TWO HIGHER. MAY SEE A
FEW MORE 90F READINGS. BASED ON LTST LAMP AND YDA RSLTS...MADE A
CPL MINOR MODIFICATIONS.
OTHER THAN THE TROUGH AXIS AND TRRN...THERE WILL NOT BE A FOCUSING
MECHANISM FOR CONVECTION. A MODIFIED 12Z RAOB REVELS NO SHEAR AND
ONLY MINIMAL INSTBY. HRRR ATTEMPTING TO DVLP SHRA/TSRA ALONG THE
BLURDG TAFTN. RAP AND LWX WRF-NMM12G SUGGESTING THE SAME THING BUT
IN A MUCH MORE MUTED VERSION. MEANWHILE...WRF-ARW4 THINKING ITLL
BE DRY. OPTED TO NOT ADJUST CURRENT FCST. BELIEVE THERE WL BE A
FEW SHRA/TSRA IN THE WRN CWFA...BUT DO NOT HV MUCH CONFIDENCE IN
PINPOINTING WHEN OR WHERE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
ANY CONVECTION WILL DIMINISH DURING THE EVENING. WITH LITTLE
CHANGE TO THE AIRMASS...COULD SEE SOME PATCHY FOG. LOWS WILL BE
SIMILAR WITH MOST LOCATIONS IN THE 60S...AND LOWER 70S IN THE
URBAN AREAS.
ON MONDAY...LOW LEVEL RIDGING INCHES A BIT TO THE EAST.
ALOFT...THE MEAN RIDGE CONTINUES TO BUILD OVER EASTERN NOAM...BUT
THE HEIGHT WEAKNESS REMAINS LOCALLY...WITH A POSSIBLE CLOSED LOW
DEVELOPING OFFSHORE. MODEL QPF FIELDS ARE A BIT MORE ROBUST OVER
THE MOUNTAINS THAN TODAY. WHILE THERE IS A LITTLE MORE MOISTURE
RETURN...OVERALL INSTBY LOOKS WEAKER WITH POOR MID-LEVEL LAPSE
RATES...AND THERE COULD BE RIDGING BETWEEN THE TWO CLOSED LOWS.
CONFINED POPS FARTHER WEST THAN TODAY...WITH GENERALLY ISOLATED
COVERAGE. WITH LOW LEVEL THICKNESSES INCHING UP...EXPECT MORE
AREAS INTO THE LOWER 90S. DEW POINTS REMAIN IN THE LOWER TO MID
60S THOUGH...SO HEAT INDICES WILL NOT BE MUCH HIGHER THAN THE AIR
TEMPS.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
GFS...ECMWF AND GGEM ARE IN GENERAL AGREEMENT THROUGH THE LONG
TERM WITH THE MAJOR FEATURES. ALL THREE MODELS DEPICT SURFACE HIGH
PRESSURE TO GRADUALLY SLIDE EASTWARD MONDAY NIGHT THROUGH
WEDNESDAY NIGHT. AN UPPER LEVEL LOW WILL ALSO BE LOCATED JUST TO
THE EAST OF THE DELMARVA MONDAY EVENING...WHICH WILL SLIDE EAST
MONDAY NIGHT AND TUESDAY AS A SHORTWAVE WITH MINIMAL IF ANY
SURFACE REFLECTION SLIDES NORTHEAST ACROSS THE AREA TUESDAY
AFTERNOON AND EVENING. THIS SHORTWAVE MOVES AWAY TO THE NORTHEAST
ON WEDNESDAY WITH A WEAKLY DIFFLUENT FLOW ALOFT AS WE SIT BETWEEN
A RIDGE TO OUR SOUTH AND A DEEP TROUGH TO THE WEST. A COLD FRONT
ASSOCIATED WITH SAID DEEP TROUGH THEN APPROACHES FROM THE
NORTHWEST THURSDAY AND MOVES INTO THE REGION THURSDAY NIGHT AND
FRIDAY BEFORE STALLING JUST SOUTH OF US ON SATURDAY...THOUGH MOST
OF THE ENERGY FROM THE TROUGH BYPASSES US TO THE NORTHWEST ON
FRIDAY.
BASED ON THE GENERAL PATTERN...EXPECT CHANCE OF SHOWERS AND
THUNDERSTORMS TO OCCUR TUESDAY WITH THE TROUGH PASSAGE...PERHAPS
SOME MAINLY TERRAIN CONVECTION WEDNESDAY...AND THEN BETTER CHANCE
LATER THURSDAY INTO FRIDAY AS THE FRONT APPROACHES AND THEN MOVES
INTO THE AREA. WHILE TEMPERATURES ALOFT WILL REMAIN WARM...THEY
DON`T LOOK QUITE AS WARM AS PREVIOUSLY...AND THE INCREASED RISK OF
SHOWERS/T-STORMS TUESDAY COMBINED WITH POTENTIAL OF LINGERING
CLOUDS WEDNESDAY WILL LIKELY PREVENT EXCESSIVE HEAT. DEW POINTS
ALSO DON`T LOOK EXCESSIVE WITH READINGS STARTING IN THE MID 60S
MONDAY EVENING AND THEN SLOWLY RISE TO NEAR 70 BY THURSDAY...WHICH
IS HUMID BUT NOT UNUSUAL FOR AUGUST. LOWS WILL BE CREEPING UP WITH
THE INCREASED CLOUD COVER AND MOISTURE...WITH LOWER 70S BECOMING
COMMON LATER IN THE WEEK.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
VFR TODAY WITH LIGHT SOUTHERLY FLOW. BAY BREEZE WL AFFECT MTN...
AND MAY REACH BWI. ANY SHOWERS/STORMS SHOULD STAY WEST OF THE
TERMINALS. WITH STAGNANT PATTERN...FOG COULD BE A POSSIBILITY
AGAIN TONIGHT. COVERAGE/MAGNITUDE UNCERTAIN THOUGH...BUT LIKELY
NOT IN METROS. FOR MONDAY...VFR AND LIGHT SOUTHERLY WINDS
EXPECTED.
OVERALL VFR MONDAY NIGHT THROUGH THURSDAY. BEST CHANCE OF SUB-VFR
IS IN SHOWER/T-STORMS...WITH BEST CHANCE OF THOSE BEING THURSDAY-
FRIDAY. WINDS GENERALLY SOUTHERLY 5-10 KNOTS...POSSIBLY CLOSER TO
15 KNOTS BY THURSDAY AS COLD FRONT APPROACHES.
&&
.MARINE...
HIGH PRESSURE OVER THE REGION THIS MORNING WILL GRADUALLY SLIDE
OFFSHORE MONDAY. PREVAILING FLOW WILL BE FROM THE S OR
SE...ALTHOUGH WITH WEAK PRESSURE PATTERNS...LOCALIZED LAND
CIRCULATIONS COULD DEVELOP. SPEEDS GENERALLY 5-10 KT...POSSIBLY TO
15 KT AT TIMES OVER THE BAY.
WINDS MAY APPROACH SCA LEVELS AS BERMUDA HIGH SHIFTS EAST THROUGH
THE WEEK. BEST CHANCE IS THURSDAY AS A COLD FRONT APPROACHES.
SHOWERS AND THUNDERSTORMS ALSO A CONCERN...WITH BEST CHANCE OF
THEM BEING THURSDAY.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...RCM
NEAR TERM...ADS/HTS
SHORT TERM...ADS
LONG TERM...RCM
AVIATION...ADS/RCM/HTS
MARINE...ADS/RCM
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1152 PM EDT MON AUG 17 2015
.AVIATION...
VFR CONDITIONS WILL AGAIN BE THE RULE...OUTSIDE OF A PERIOD OF
PATCHY MVFR FOG AROUND DAWN. WHILE THERE WILL LIKELY BE WIDELY
SCATTERED SHRAS OR TSRAS AT TIMES ON TUESDAY...TIMING IS VERY
DIFFICULT TO PIN DOWN AND WILL MAINTAIN DRY FORECAST GIVEN LACK OF
COVERAGE EXPECTED. DO EXPECT LOWER VFR/MVFR BKN CIGS AT TIMES LATE
IN THE DAY.
FOR DTW...SIMILAR DAY EXPECTED AGAIN TUESDAY AFTERNOON WITH CU
AROUND 3500 FEET TRENDING FROM SCT TO BKN DURING THE AFTERNOON.
WHILE A FEW SHRAS WILL BE POSSIBLE...TIMING/COVERAGE QUESTIONS
SUGGEST LEAVING OUT OF THE FORECAST ATTM.
//DTW THRESHOLD PROBABILITIES...
* MEDIUM FOR CEILING AOB 5KFT TUESDAY AFTERNOON.
* LOW FOR THUNDERSTORMS TUESDAY.
&&
.PREV DISCUSSION...ISSUED 350 PM EDT MON AUG 17 2015
SHORT TERM...THROUGH TONIGHT
WELL-DEFINED UPPER WAVE PER WATER VAPOR IMAGERY WILL TRACK FROM THE
ILLINOIS/INDIANA BORDER UP INTO SOUTHERN LOWER MICHIGAN TONIGHT AS
WESTERLY WINDS ALOFT STRENGTHEN IN RESPONSE TO AN UPPER TROUGH
DIGGING INTO THE NORTHERN ROCKIES/PLAINS. THE FRONTAL BOUNDARY OVER
NORTHERN MICHIGAN IS NOT EXPECTED TO MAKE TOO MUCH SOUTHWARD
PROGRESS TONIGHT...ONLY DROPPING A LITTLE FURTHER INTO NORTHERN
LOWER MICHIGAN...WITH ITS SLOWING ALSO A RESULT OF THE DEEPENING
TROUGH.
MOISTURE ADVECTION INTO SOUTHEAST MICHIGAN STILL LOOKS BEST AFTER
21Z. MOISTURE PLUME CAN BE SEEN ON WATER VAPOR LIFTING IN AHEAD OF
THE UPPER WAVE ATTM. PW VALUES WERE ALREADY FAIRLY HIGH ON THE 12Z
DTX RAOB...AND ARE FORECAST BY NAM/GFS TO RISE TO AROUND 1.7 INCHES
BY 00Z. FORCING WILL BE THE STRONGEST AS THE UPPER WAVE NEARS THE
MICHIGAN BORDER THIS EVENING AND THEN TRACKS OVERHEAD OVERNIGHT.
UNTIL THEN...SHOWERS/STORMS HAVE BEEN FIRING OVER THE FAR SOUTHERN
PART OF THE STATE WHERE THETA-E ADVECTION HAS BEEN STRONGER. EXPECT
SCATTERED SHOWERS/TSTORMS TO CONTINUE DEVELOPING THROUGH THE
EVENING...INCREASING IN COVERAGE AS SYNOPTIC FORCING INCREASES AND
TEMPERATURES ALOFT COOL SLIGHTLY AND STEEPEN LAPSE RATES.
THUNDERSTORMS WILL HAVE POTENTIAL TO PRODUCE VERY HEAVY RAINFALL
GIVEN HIGH DEGREE OF MOISTURE...GOOD INSTABILITY (1500-1700 J/KG ML
CAPE) THIS EVENING...AND SLOW STORM MOVEMENT AT ONLY 15 MPH. A FEW
STORMS MAY BECOME A LITTLE STRONG...PRODUCING WIND GUSTS TO 40 MPH.
THIS HAS ALREADY BEEN EVIDENCED BY A STORM THAT FORMED OVER FAR
WESTERN LAKE ERIE EARLIER TODAY...WHEN A 50 DBZ CORE QUICKLY PULSED
UP TO AROUND 21000FT. PAST SEVERAL RUNS OF THE HRRR HAVE HINTED THAT
VERY SMALL INDIVIDUAL CELLS THAT HAVE BEEN DEVELOPING WILL CONGEAL
INTO A LARGER AREA OF LIGHT SHOWERS LATER THIS EVENING AS CLOUD
COVER OVERSPREADS THE AREA AND WE LOSE DAYTIME HEATING.
TEMPERATURES WILL REMAIN FAIRLY WARM TONIGHT AS DEWPOINTS STAY IN
THE 60S AND CLOUD COVER LIMITS RADIATIONAL COOLING. THIS SHOULD KEEP
MIN TEMPS IN THE MID 60S TO NEAR 70.
LONG TERM...
RELATIVELY MOIST AIRMASS /PWAT VALUES 1.5-1.75 IN/ WILL LINGER OVER
THE GREAT LAKES ON TUESDAY. DISORGANIZED PATTERN MAKES IT HARD TO
IDENTIFY A GOOD LIFTING MECHANISM SO CONFIDENCE IS NOT PARTICULARLY
HIGH ON COVERAGE AND LOCATION OF SHOWERS. WEAKENING SHORTWAVE
TRACKING THROUGH THE STATE IN SOUTHWESTERLY FLOW SHOULD PROVIDE SOME
LIFT. MIDLEVEL MOISTURE LOOKS TO BE A BIT HIGHER OVER MID-MICHIGAN
INCLUDING THE TRI-CITIES AREA SO KEPT LIKELY POPS THERE BUT
GENERALLY BACKED OFF A BIT ON POPS. MEAGER LAPSE RATES WILL LIMIT
INSTABILITY THOUGH A FEW STORMS ARE STILL POSSIBLE WITH
WEAKLY NEGATIVE LIFTED INDICES DURING THE AFTERNOON. TEMPS
ARE EXPECTED TO BE SEVERAL DEGREES COOLER THAN MONDAY WITH THE UPPER
RIDGE HAVING DEPARTED ALONG WITH RELATIVELY HIGH CLOUD FRACTION.
A MILD NIGHT TUESDAY NIGHT WITH A FEW LINGERING SHOWERS POSSIBLE
THOUGH LIKELY WITH LESS COVERAGE THAN DURING THE DAY OWING TO LACK
OF DIURNAL INSTABILITY AND SUBTLE SHORTWAVE UPPER RIDGING.
ON WEDNESDAY...SHORTWAVE ENERGY WILL CONTINUE TO WRAP INTO THE DEEP
TROUGH OVER THE CENTRAL PLAINS AS IT DRIFTS NORTHEASTWARD. AT THE
SURFACE...AN UNSEASONABLY STRONG SURFACE LOW WILL OCCLUDE SOMEWHERE
IN THE VICINITY OF DULUTH MN. STILL VARYING SOLUTIONS WITH RESPECT
TO STRENGTH AND LOCATION OF THIS LOW AND RESULTING TIMING OF COLD
FRONT PUSH ACROSS LOWER MICHIGAN. A SLIGHTLY SLOWER TREND WAS NOTED
IN SOME OF THE 12Z GUIDANCE...WHICH LED TO INCREASING POPS FOR
WEDNESDAY NIGHT. CURRENT THINKING IS THAT THE PEAK TIME FOR PRECIP
IS LATE WEDNESDAY/EARLY WEDNESDAY NIGHT ALONG AND AHEAD OF THE
FRONT. HAVE TO HONOR SEVERE WEATHER THREAT DUE TO THE OVERALL
STRENGTH OF THE SYSTEM. HOWEVER...SIGNIFICANT QUESTION MARKS
EXIST. DEEP-LAYER SHEAR LOOKS TO BE LIMITED IN THE WARM SECTOR...AND
INSTABILITY IS A QUESTION MARK OWING TO WEAK MIDLEVEL LAPSE RATES
AND GOOD CLOUD COVERAGE. A LATER TIMING OF THE FRONT ALSO CASTS
DOUBT UPON SEVERE WEATHER POTENTIAL...ESPECIALLY IF SLOWER TREND
CONTINUES. AS FOR TEMPS...STRONGER SOUTHERLY WINDS ON WEDNESDAY WILL
BUMP UP HIGH TEMPS A COUPLE DEGREES RELATIVE TO TUESDAY.
RAIN SHOWERS WILL COME TO AN END EARLY THURSDAY AS STRONG HIGH
PRESSURE BUILDS INTO THE GREAT LAKES. THIS HIGH WILL STICK AROUND
THROUGH SATURDAY...KEEPING CONDITIONS DRY ACROSS SOUTHEAST MICHIGAN
THROUGH THE FIRST HALF OF THE WEEKEND. THERE IS A BIT OF TIMING
DIFFERENCES FOR THE NEXT COLD FRONT ASSOCIATED WITH A LOW PRESSURE
SYSTEM TRACKING OVER CANADA. SOME MODELS HAVE THE FRONT /AND
THEREFORE RAIN AND THUNDERSTORMS/ PUSHING THROUGH ON SUNDAY WITH
OTHERS NOT HAVING THE FRONT ARRIVING UNTIL EARLY MONDAY MORNING.
WILL HAVE TO KEEP AN EYE ON THIS FEATURE OVER THE NEXT COUPLE DAYS
AS TIMING GETS MORE CERTAIN.
MARINE...
INCREASING MOISTURE FROM THE WEST WILL SUPPORT PERIODS OF SHOWERS
AND THUNDERSTORMS TONIGHT THROUGH WEDNESDAY NIGHT...WITH THE MOST
WIDESPREAD ACTIVITY LIKELY WEDNESDAY AND WEDNESDAY NIGHT. A
DISORGANIZED PRESSURE PATTERN WILL RESULT IN GENERALLY LIGHT WINDS
TONIGHT INTO TUESDAY. EASTERLY/SOUTHEASTERLY FLOW WILL INCREASE
MODESTLY ON WEDNESDAY AS A LOW PRESSURE SYSTEM STRENGTHENS NEAR
DULUTH MN. THIS SYSTEM WILL PUSH A STRONG COLD FRONT THROUGH THE
WATERS LATE WEDNESDAY/WEDNESDAY NIGHT WITH BREEZY SOUTHWESTERLY FLOW
DEVELOPING BEHIND THE FRONT ON THURSDAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....DG
SHORT TERM...HLO
LONG TERM....DT/RK
MARINE.......DT
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
851 PM EDT MON AUG 17 2015
.UPDATE...
ISSUED AT 848 PM EDT MON AUG 17 2015
ADDED SOME ISOLD SHOWERS TO THE FCST FOR WRN UPR MI OVERNGT TO
ACCOUNT FOR AREA OF SHOWERS MOVING SLOWLY NE THRU NW WI AHEAD OF
DISTURBANCE IN SW MN AND UNDER COOLING CLD TOPS. POTENT SHRTWV
DIGGING INTO THE NRN PLAINS WL LIKELY CAUSE THE UPR FLOW TO BACK ENUF
TO LIFT THESE SHOWERS INTO THE WRN CWA. ONLY THE LATEST RAPID REFRESH
MODEL HAS A GOOD HANDLE ON THE LOCATION OF THE PCPN AT PRESENT TIME.
THIS MODEL SHOWS THESE SHOWERS SPREADING INTO WRN UPR MI AFTER MIDNGT
DESPITE SOME DRIER LLVL AIR THAT WL RESTRICT THE COVERAGE/INTENSITY.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 443 PM EDT MON AUG 17 2015
WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A BROAD TROF EXTENDING S
INTO THE NRN ROCKIES NRN PLAINS. POTENT LOOKING SHORTWAVE OVER SW MT
WILL GENERATE AN UNUSUALLY STRONG SFC LOW FOR AUG THAT WILL MOVE
ACROSS THE UPPER MISSISSIPPI VALLEY/UPPER GREAT LAKES TUE NIGHT/WED.
SYSTEM ON WATER VAPOR IMAGERY LOOKS STRONGER THAN INDICATED BY
MODELS RIGHT NOW...SO IT WILL BE INTERESTING TO SEE HOW THIS SYSTEM
EVOLVES. TO THE E AND AT THE SFC...COLD FRONT HAS DRIFTED S OF UPPER
MI. WEAKER SHORTWAVES AND RIGHT ENTRANCE OF UPPER JET EXTENDING FROM
NRN MN TO NRN QUEBEC ARE AIDING SHRA/TSTMS FROM IA/SRN MN ENE TO ERN
UPPER MI AND LWR MI. PER LATEST SPC ANALYSIS NRN EDGE OF INSTABILITY
(MLCAPES EXCEEDING 100J/KG) ONLY EXTENDS AS FAR N AS NEAR KMNM AND
THEN E ACROSS NRN LAKE MI. THUS...NO THUNDER HAS BEEN NOTED IN UPPER
MI THIS AFTN.
RIGHT ENTRANCE OF A LESS WELL-DEFINED WITH TIME UPPER JET WILL POSE
SOME RISK FOR GENERATING -SHRA AT TIMES TONIGHT TO THE N OF THE COLD
FRONT WHICH WILL BECOME NEARLY STATIONARY. THERE MAY BE A SUBTLE
SHORTWAVE UPSTREAM AS WELL WHICH COULD AID -SHRA DEVELOPMENT FARTHER
N PER ECWMF...BUT STAYED CLOSE TO THE MULTI-MODEL CONSENSUS IN
CARRYING SCHC POPS FOR AT LEAST SOME PORTION OF THE NIGHT OVER
ROUGHLY THE SE HALF OF THE FCST AREA. CHC POPS WERE CONFINED TO THE
FAR SCNTRL...AND ALSO SE CLOSE TO LAKE MI THIS EVENING. NOT
EXPECTING ANY TSTMS. MAY SEE SOME PATCHY FOG OVERNIGHT.
ON TUE...SFC LOW PRES ORGANIZES OVER THE PLAINS AND REACHES NW IA
LATE IN THE DAY IN RESPONSE TO THE STRONG SHORTWAVE MOVING OUT OVER
THE PLAINS. STRENGTHENING DEEP LAYER FORCING AND STRONG MOISTURE
TRANSPORT AHEAD OF FEATURE WILL SPREAD OVER MN AND THEN TOWARD NW
WI/WRN LAKE SUPERIOR/WRN UPPER MI LATE IN THE AFTN...RESULTING IN AN
INCREASING AREA OF MDT/HVY RAIN AND EMBEDDED THUNDER ORGANIZING TO
THE W AND SW. LOOKS LIKE MUCH OF THIS PCPN WILL HOLD OFF UNTIL TUE
NIGHT. AS FRONT TO THE S BEGINS TO MOVE BACK TO THE N AS A WARM
FRONT...PROBABLY CAN`T RULE OUT A FEW -SHRA DEVELOPING N OF THE
FRONT AS WAA BEGINS...BUT AT LEAST RIGHT NOW...POTENTIAL APPEARS
QUITE LOW. ONLY SCHC WILL BE UTILIZED EXCEPT FOR THE W IN THE AFTN
WHERE POPS WILL INCREASE THRU THE CHC CATEGORY.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 332 PM EDT MON AUG 17 2015
A LOW INTENSIFYING ALONG THE MINNESOTA AND IOWA BORDER AT THE START
OF THE PERIOD WILL BRING UNSETTLED WEATHER FOR THE UPPER GREAT
LAKES REGION THROUGH THE FIRST HALF OF THE LONG TERM FORECAST. THIS
LOW WILL BE AROUND 998MB AND WILL BE LIFTING TO THE NORTH TUESDAY
NIGHT INTO WEDNESDAY (WHILE STRENGTHENING TO 993MB) IN RESPONSE TO
A SHORTWAVE ROUNDING THE BASE OF THE UPPER TROUGH IN THE NORTHERN
PLAINS. THERE ARE SOME DIFFERENCES IN THE MODELS ON HOW FAST THIS
LOW (ANOMALOUS FOR MID-LATE AUGUST) WILL MOVE NORTH THROUGH THE
DULUTH AREA AND ACROSS WESTERN LAKE SUPERIOR ON WEDNESDAY...BUT WITH
THE RECENT TRENDS HEADING TOWARDS A SLOWER DEPARTURE FROM LAKE
SUPERIOR...WILL FOLLOW THAT IDEA IN THE FORECAST.
EXPECT A FEW WAVES OF PRECIPITATION TO MOVE THROUGH THE U.P. WITH
THIS LOW...BUT UNFORTUNATELY THE TRACK WILL NOT PROMOTE A
MUCH NEEDED WIDESPREAD AND SOAKING RAIN FOR MOST OF THE AREA. THE
FIRST WAVE WILL ARRIVE LATE TOMORROW AFTERNOON AND INTO TOMORROW
NIGHT AS BROAD MID LEVEL WARM AIR ADVECTION SWEEPS NORTH ACROSS THE
AREA. THE BEST ASCENT WILL BE TO THE WEST-NORTHWEST OF THE AREA AND
TOWARDS THE MINNESOTA ARROWHEAD...BUT THE WESTERN U.P. COULD BE
BRUSHED BY SOME OF THE STRONGER AREAS OF RAIN. OTHERWISE...EXPECT
RAINFALL AMOUNTS TO SLOWLY DIMINISH FROM AROUND AN INCH OVER THE FAR
WEST TO A HALF AN INCH OR LESS TO THE EAST OF NEWBERRY.
THE NEXT WAVE WILL PUSH NORTH-NORTHEAST THROUGH THE CWA ON
WEDNESDAY MORNING AND PRODUCE AN AREA OF SCATTERED/NUMEROUS SHOWERS
AND MAYBE A FEW THUNDERSTORMS AS IT MOVES THROUGH THE AREA. WILL
SHOW A PERIOD OF THUNDER CHANCES ALONG THAT FRONT AS IT MOVES
THROUGH...TIED TO THE LOWER SHOWALTER VALUES AND MUCAPE VALUES
RISING BETWEEN 500-750 J/KG RIGHT ALONG THE FRONT. EFFECTIVE SHEAR
VALUES LOOK TO BE FAIRLY LOW...SO THAT SHOULD ELIMINATE MUCH OF THE
SEVERE THREAT...EXCEPT FOR AREAS RIGHT ALONG THE COLD FRONT WHICH
WILL TRY TO PUSH EFFECTIVE SHEAR VALUES UP TOWARDS 30KTS. AS THIS
FRONT MOVES NORTH THROUGH THE DAY AND THE DRY SLOT MOVES OVER THE
AREA ALOFT...HAVE TRENDED POPS DOWN OVER THE CENTRAL AND EAST
THROUGH THE DAY...WITH ONLY SLIGHT CHANCES IN THE AFTERNOON
(ALTHOUGH THAT MAY BE TOO HIGH). WRAP AROUND RAIN WILL THEN ARRIVE
OVER THE WEST LATE WEDNESDAY AFTERNOON AND CONTINUE INTO WEDNESDAY
NIGHT. EXPECT THE SCATTERED/NUMEROUS SHOWERS TO STAY MORE OVER THE
WESTERN U.P. BUT DID SPREAD CHANCES EAST OVERNIGHT INTO THURSDAY FOR
MUCH OF THE REST OF THE U.P. WINDS WILL ALSO BE ON THE INCREASE
LATE WEDNESDAY NIGHT INTO THURSDAY MORNING BEHIND THE LOW DUE TO
THE COMBINED PRESSURE RISE AND STEEPENING LOW LEVEL LAPSE RATES
TOWARDS 8-9 C/KM BETWEEN THE SURFACE AND 900MB. THAT WILL LIKELY
PRODUCE GUSTS TO 30KTS OVER WESTERN/CENTRAL LAKE SUPERIOR AND
20-30KTS OVER MOST LAND AREAS.
CONDITIONS WILL IMPROVE THURSDAY NIGHT AS A HIGH PRESSURE RIDGE
BUILDS INTO THE AREA. THIS WILL BRING DECREASING CLOUDS AND WINDS
THROUGH THE NIGHT AND SHOULD LEAD TO A NICE DAY ACROSS THE AREA ON
FRIDAY. THE SUNSHINE WILL BRING HIGHS BACK UP TO NORMAL OR SLIGHTLY
ABOVE NORMAL VALUES ON FRIDAY AND EXPECT TEMPERATURES A TOUCH
WARMER ON SATURDAY (AROUND 80) WITH THE SOUTHERLY FLOW.
ANOTHER STRONG UPPER TROUGH WILL MOVE INTO THE NORTHERN PLAINS ON
SATURDAY AND MOVE THROUGH THE AREA SUNDAY INTO SUNDAY NIGHT. WILL
CONTINUE TO SHOW HIGH CHANCE AND LOW END LIKELY POPS AS THAT MOVES
THROUGH THE AREA BEFORE SLOWLY DEPARTING ON MONDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 722 PM EDT MON AUG 17 2015
ALTHOUGH LLVL DRY AIR WL BRING VFR CONDITIONS TO CMX/IWD TNGT...SAW
MAY SEE SOME MVFR CIGS AT TIMES WITH MOISTER...UPSLOPE NE FLOW
CLOSER TO STALLED FNT JUST TO THE SE OF UPR MI IN THE PRESENCE OF
NOCTURNAL COOLING. DAYTIME HEATING WL BRING AN IMPROVEMENT TO VFR
CIGS AT SAW ON TUE MRNG...BUT LOWER MVFR CIGS WL RETURN TO THAT SITE
ALONG WITH THE CHC FOR SOME -SHRA LATE IN THE DAY AS THE STALLED FNT
BEGINS MOVING TO THE N. SOME -SHRA WL RETURN TO IWD AS WELL...BUT
DOWNSLOPE NATURE OF THE LLVL WIND THERE SHOULD MAINTAIN VFR
CONDITIONS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 443 PM EDT MON AUG 17 2015
HIGH PRES STRETCHING FROM SOUTHERN MANITOBA THROUGH JAMES BAY WILL
EXTEND A RIDGE INTO THE UPPER LAKES THRU TUE MORNING...RESULTING IN
LIGHT WINDS UNDER 15KT ACROSS LAKE SUPERIOR THRU TUE MORNING.
THEN...AS LOW PRES ORGANIZES AND STRENGTHENS OVER THE PLAINS
TUE...NE WINDS WILL BEGIN TO RAMP UP...ESPECIALLY OVER WRN LAKE
SUPERIOR WHERE GUSTS SHOULD REACH 25-30KT LATE AFTN/EARLY EVENING.
THIS LOW WILL BECOME UNSEASONABLY DEEP FOR AUG AS IT LIFTS ACROSS
FAR WRN LAKE SUPERIOR WED AFTN. 20-30KT WINDS ARE EXPECTED OVER MUCH
OF THE LAKE TUE NIGHT INTO WED. MAY SEE GALE FORCE GUSTS OVER FAR
WRN LAKE SUPERIOR IN THE NE WINDS AHEAD OF THE LOW TUE NIGHT AND
THEN IN THE WESTERLY WINDS ACROSS MAINLY CENTRAL LAKE SUPERIOR ON
THU AS THE LOW LIFTS N OF THE AREA. WINDS WILL DIMINISH TO UNDER
20KT FRI...AND THEN BEGIN TO INCREASE AGAIN ON SAT AHEAD OF THE NEXT
COLD FRONT MOVING OUT ACROSS THE PLAINS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...KC
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
723 PM EDT MON AUG 17 2015
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 443 PM EDT MON AUG 17 2015
WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A BROAD TROF EXTENDING S
INTO THE NRN ROCKIES NRN PLAINS. POTENT LOOKING SHORTWAVE OVER SW MT
WILL GENERATE AN UNUSUALLY STRONG SFC LOW FOR AUG THAT WILL MOVE
ACROSS THE UPPER MISSISSIPPI VALLEY/UPPER GREAT LAKES TUE NIGHT/WED.
SYSTEM ON WATER VAPOR IMAGERY LOOKS STRONGER THAN INDICATED BY
MODELS RIGHT NOW...SO IT WILL BE INTERESTING TO SEE HOW THIS SYSTEM
EVOLVES. TO THE E AND AT THE SFC...COLD FRONT HAS DRIFTED S OF UPPER
MI. WEAKER SHORTWAVES AND RIGHT ENTRANCE OF UPPER JET EXTENDING FROM
NRN MN TO NRN QUEBEC ARE AIDING SHRA/TSTMS FROM IA/SRN MN ENE TO ERN
UPPER MI AND LWR MI. PER LATEST SPC ANALYSIS NRN EDGE OF INSTABILITY
(MLCAPES EXCEEDING 100J/KG) ONLY EXTENDS AS FAR N AS NEAR KMNM AND
THEN E ACROSS NRN LAKE MI. THUS...NO THUNDER HAS BEEN NOTED IN UPPER
MI THIS AFTN.
RIGHT ENTRANCE OF A LESS WELL-DEFINED WITH TIME UPPER JET WILL POSE
SOME RISK FOR GENERATING -SHRA AT TIMES TONIGHT TO THE N OF THE COLD
FRONT WHICH WILL BECOME NEARLY STATIONARY. THERE MAY BE A SUBTLE
SHORTWAVE UPSTREAM AS WELL WHICH COULD AID -SHRA DEVELOPMENT FARTHER
N PER ECWMF...BUT STAYED CLOSE TO THE MULTI-MODEL CONSENSUS IN
CARRYING SCHC POPS FOR AT LEAST SOME PORTION OF THE NIGHT OVER
ROUGHLY THE SE HALF OF THE FCST AREA. CHC POPS WERE CONFINED TO THE
FAR SCNTRL...AND ALSO SE CLOSE TO LAKE MI THIS EVENING. NOT
EXPECTING ANY TSTMS. MAY SEE SOME PATCHY FOG OVERNIGHT.
ON TUE...SFC LOW PRES ORGANIZES OVER THE PLAINS AND REACHES NW IA
LATE IN THE DAY IN RESPONSE TO THE STRONG SHORTWAVE MOVING OUT OVER
THE PLAINS. STRENGTHENING DEEP LAYER FORCING AND STRONG MOISTURE
TRANSPORT AHEAD OF FEATURE WILL SPREAD OVER MN AND THEN TOWARD NW
WI/WRN LAKE SUPERIOR/WRN UPPER MI LATE IN THE AFTN...RESULTING IN AN
INCREASING AREA OF MDT/HVY RAIN AND EMBEDDED THUNDER ORGANIZING TO
THE W AND SW. LOOKS LIKE MUCH OF THIS PCPN WILL HOLD OFF UNTIL TUE
NIGHT. AS FRONT TO THE S BEGINS TO MOVE BACK TO THE N AS A WARM
FRONT...PROBABLY CAN`T RULE OUT A FEW -SHRA DEVELOPING N OF THE
FRONT AS WAA BEGINS...BUT AT LEAST RIGHT NOW...POTENTIAL APPEARS
QUITE LOW. ONLY SCHC WILL BE UTILIZED EXCEPT FOR THE W IN THE AFTN
WHERE POPS WILL INCREASE THRU THE CHC CATEGORY.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 332 PM EDT MON AUG 17 2015
A LOW INTENSIFYING ALONG THE MINNESOTA AND IOWA BORDER AT THE START
OF THE PERIOD WILL BRING UNSETTLED WEATHER FOR THE UPPER GREAT
LAKES REGION THROUGH THE FIRST HALF OF THE LONG TERM FORECAST. THIS
LOW WILL BE AROUND 998MB AND WILL BE LIFTING TO THE NORTH TUESDAY
NIGHT INTO WEDNESDAY (WHILE STRENGTHENING TO 993MB) IN RESPONSE TO
A SHORTWAVE ROUNDING THE BASE OF THE UPPER TROUGH IN THE NORTHERN
PLAINS. THERE ARE SOME DIFFERENCES IN THE MODELS ON HOW FAST THIS
LOW (ANOMALOUS FOR MID-LATE AUGUST) WILL MOVE NORTH THROUGH THE
DULUTH AREA AND ACROSS WESTERN LAKE SUPERIOR ON WEDNESDAY...BUT WITH
THE RECENT TRENDS HEADING TOWARDS A SLOWER DEPARTURE FROM LAKE
SUPERIOR...WILL FOLLOW THAT IDEA IN THE FORECAST.
EXPECT A FEW WAVES OF PRECIPITATION TO MOVE THROUGH THE U.P. WITH
THIS LOW...BUT UNFORTUNATELY THE TRACK WILL NOT PROMOTE A
MUCH NEEDED WIDESPREAD AND SOAKING RAIN FOR MOST OF THE AREA. THE
FIRST WAVE WILL ARRIVE LATE TOMORROW AFTERNOON AND INTO TOMORROW
NIGHT AS BROAD MID LEVEL WARM AIR ADVECTION SWEEPS NORTH ACROSS THE
AREA. THE BEST ASCENT WILL BE TO THE WEST-NORTHWEST OF THE AREA AND
TOWARDS THE MINNESOTA ARROWHEAD...BUT THE WESTERN U.P. COULD BE
BRUSHED BY SOME OF THE STRONGER AREAS OF RAIN. OTHERWISE...EXPECT
RAINFALL AMOUNTS TO SLOWLY DIMINISH FROM AROUND AN INCH OVER THE FAR
WEST TO A HALF AN INCH OR LESS TO THE EAST OF NEWBERRY.
THE NEXT WAVE WILL PUSH NORTH-NORTHEAST THROUGH THE CWA ON
WEDNESDAY MORNING AND PRODUCE AN AREA OF SCATTERED/NUMEROUS SHOWERS
AND MAYBE A FEW THUNDERSTORMS AS IT MOVES THROUGH THE AREA. WILL
SHOW A PERIOD OF THUNDER CHANCES ALONG THAT FRONT AS IT MOVES
THROUGH...TIED TO THE LOWER SHOWALTER VALUES AND MUCAPE VALUES
RISING BETWEEN 500-750 J/KG RIGHT ALONG THE FRONT. EFFECTIVE SHEAR
VALUES LOOK TO BE FAIRLY LOW...SO THAT SHOULD ELIMINATE MUCH OF THE
SEVERE THREAT...EXCEPT FOR AREAS RIGHT ALONG THE COLD FRONT WHICH
WILL TRY TO PUSH EFFECTIVE SHEAR VALUES UP TOWARDS 30KTS. AS THIS
FRONT MOVES NORTH THROUGH THE DAY AND THE DRY SLOT MOVES OVER THE
AREA ALOFT...HAVE TRENDED POPS DOWN OVER THE CENTRAL AND EAST
THROUGH THE DAY...WITH ONLY SLIGHT CHANCES IN THE AFTERNOON
(ALTHOUGH THAT MAY BE TOO HIGH). WRAP AROUND RAIN WILL THEN ARRIVE
OVER THE WEST LATE WEDNESDAY AFTERNOON AND CONTINUE INTO WEDNESDAY
NIGHT. EXPECT THE SCATTERED/NUMEROUS SHOWERS TO STAY MORE OVER THE
WESTERN U.P. BUT DID SPREAD CHANCES EAST OVERNIGHT INTO THURSDAY FOR
MUCH OF THE REST OF THE U.P. WINDS WILL ALSO BE ON THE INCREASE
LATE WEDNESDAY NIGHT INTO THURSDAY MORNING BEHIND THE LOW DUE TO
THE COMBINED PRESSURE RISE AND STEEPENING LOW LEVEL LAPSE RATES
TOWARDS 8-9 C/KM BETWEEN THE SURFACE AND 900MB. THAT WILL LIKELY
PRODUCE GUSTS TO 30KTS OVER WESTERN/CENTRAL LAKE SUPERIOR AND
20-30KTS OVER MOST LAND AREAS.
CONDITIONS WILL IMPROVE THURSDAY NIGHT AS A HIGH PRESSURE RIDGE
BUILDS INTO THE AREA. THIS WILL BRING DECREASING CLOUDS AND WINDS
THROUGH THE NIGHT AND SHOULD LEAD TO A NICE DAY ACROSS THE AREA ON
FRIDAY. THE SUNSHINE WILL BRING HIGHS BACK UP TO NORMAL OR SLIGHTLY
ABOVE NORMAL VALUES ON FRIDAY AND EXPECT TEMPERATURES A TOUCH
WARMER ON SATURDAY (AROUND 80) WITH THE SOUTHERLY FLOW.
ANOTHER STRONG UPPER TROUGH WILL MOVE INTO THE NORTHERN PLAINS ON
SATURDAY AND MOVE THROUGH THE AREA SUNDAY INTO SUNDAY NIGHT. WILL
CONTINUE TO SHOW HIGH CHANCE AND LOW END LIKELY POPS AS THAT MOVES
THROUGH THE AREA BEFORE SLOWLY DEPARTING ON MONDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 722 PM EDT MON AUG 17 2015
ALTHOUGH LLVL DRY AIR WL BRING VFR CONDITIONS TO CMX/IWD TNGT...SAW
MAY SEE SOME MVFR CIGS AT TIMES WITH MOISTER...UPSLOPE NE FLOW
CLOSER TO STALLED FNT JUST TO THE SE OF UPR MI IN THE PRESENCE OF
NOCTURNAL COOLING. DAYTIME HEATING WL BRING AN IMPROVEMENT TO VFR
CIGS AT SAW ON TUE MRNG...BUT LOWER MVFR CIGS WL RETURN TO THAT SITE
ALONG WITH THE CHC FOR SOME -SHRA LATE IN THE DAY AS THE STALLED FNT
BEGINS MOVING TO THE N. SOME -SHRA WL RETURN TO IWD AS WELL...BUT
DOWNSLOPE NATURE OF THE LLVL WIND THERE SHOULD MAINTAIN VFR
CONDITIONS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 443 PM EDT MON AUG 17 2015
HIGH PRES STRETCHING FROM SOUTHERN MANITOBA THROUGH JAMES BAY WILL
EXTEND A RIDGE INTO THE UPPER LAKES THRU TUE MORNING...RESULTING IN
LIGHT WINDS UNDER 15KT ACROSS LAKE SUPERIOR THRU TUE MORNING.
THEN...AS LOW PRES ORGANIZES AND STRENGTHENS OVER THE PLAINS
TUE...NE WINDS WILL BEGIN TO RAMP UP...ESPECIALLY OVER WRN LAKE
SUPERIOR WHERE GUSTS SHOULD REACH 25-30KT LATE AFTN/EARLY EVENING.
THIS LOW WILL BECOME UNSEASONABLY DEEP FOR AUG AS IT LIFTS ACROSS
FAR WRN LAKE SUPERIOR WED AFTN. 20-30KT WINDS ARE EXPECTED OVER MUCH
OF THE LAKE TUE NIGHT INTO WED. MAY SEE GALE FORCE GUSTS OVER FAR
WRN LAKE SUPERIOR IN THE NE WINDS AHEAD OF THE LOW TUE NIGHT AND
THEN IN THE WESTERLY WINDS ACROSS MAINLY CENTRAL LAKE SUPERIOR ON
THU AS THE LOW LIFTS N OF THE AREA. WINDS WILL DIMINISH TO UNDER
20KT FRI...AND THEN BEGIN TO INCREASE AGAIN ON SAT AHEAD OF THE NEXT
COLD FRONT MOVING OUT ACROSS THE PLAINS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...KC
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
212 PM EDT SUN AUG 16 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 518 AM EDT SUN AUG 16 2015
WV IMAGERY AND RAP ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE FROM
THE SW CONUS THROUGH THE SRN GREAT LAKES RESULTING IN WSW FLOW FROM
THE THE CNTRL ROCKIES THROUGH THE NRN LAKES. A SHORTWAVE TROUGH WAS
MOVING THROUGH CNTRL MANITOBA. AT THE SFC...SW FLOW WAS INCREASING
FROM THE UPPER MS VALLEY INTO THE NRN LAKES AHEAD OF A COLD FRONT
INTO NW MN EXTENDING FROM LOW PRES OVER NW ONTARIO. A LINE OF
SHRA/TSRA AHEAD OF THE FRONT FROM NEAR KELO INTO SW MN WAS
DIMINISHING AS IT MOVES AWAY FROM THE AXIS OF HIGHER INSTABILITY.
TODAY...EXPECT CONTINUED VERY WARM CONDITIONS AS MIXING TO 850 MB
TEMPS AROUND 20C SUPPORT HIGHS NEAR 90. SW DOWNSLOPE FLOW WILL BE
STRONG ENOUGH TO PREVENT LAKE BREEZE DEVELOPMENT OFF OF LAKE
SUPERIOR AND BRING ADDITIONAL WARMING TO LOCATIONS NEAR THE SHORE.
FORECAST SOUNDINGS SUGGEST THAT 800-700 MB CAPPING WILL BE STRONG
ENOUGH TO PREVENT SHRA/TSRA FROM DEVELOPING EXCEPT POSSIBLY LATE
OVER THE WEST AS THE FRONT AND FALLING HEIGHTS APPROACH.
TONIGHT...SOME SHRA/TSRA MAY BE POSSIBLE ALONG THE FRONT AS IT MOVES
INTO UPPER MICHIGAN DURING THE EVENING. HOWEVER...COVERAGE WILL BE
LIMITED WITH ONLY WEAK MID/UPPER LEVEL FORCING AND LOW LEVEL CONV
ALONG THE FRONT. EXPECT GREATER POTENTIAL FOR POST-FRONTAL PCPN
OVERNIGHT AS THE UPPER LEVEL JET MOVES INTO NW ONTARIO AND RIGHT
ENTRANCE UPPER LEVEL DIV AND ASSOCIATED 800-700 MB FGEN STRENGTHEN
OVER UPPER MI. THERE IS STILL SOME UNCERTAINTY WITH THE LOCATION OF
THE STRONGER FORCING AND WHERE THE HEAVIEST PCPN WILL DEVELOP. WITH
30-40 KNOT 0-6KM SHEAR...THERE WILL BE A LIMITED STRONG/SEVERE TSRA
THREAT...MAINLY DURING THE EVENING BEFORE THE MUCAPE IN THE 1K-2K
J/KG RANGE DIMINISHES. ALTHOUGH SOME STRONGER ELEVATED STORMS MAY
STILL BE POSSIBLE OVERNIGHT THAT COULD PRODUCE SOME HAIL...WITH
WEAKENING INSTABILITY THE SVR THREAT SHOULD ALSO TAPER OFF.
ACCORDINGLY...SPC HAS PUSHED THE MARGINAL RISK FARTHER TO THE SOUTH
OVER WI.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 437 AM EDT SUN AUG 16 2015
MUCH COOLER CONDITIONS ARE EXPECTED THROUGH THE UPCOMING WEEK...WITH
A COUPLE ROUNDS OF WIDESPREAD RAINFALL POSSIBLE.
MONDAY AND MONDAY NIGHT...A SHORTWAVE TROUGH WITHIN BROAD MID-LEVEL
TROUGHING ACROSS THE EAST HALF OF CANADA WILL BE EXITING THE CWA
NEAR THE START OF THE PERIOD. MEANWHILE...THE RIGHT ENTRANCE OF A
130KT UPPER JET STREAK WILL BE SITUATED ACROSS THE CENTRAL AND
EASTERN CWA. THIS WILL BE ENOUGH TO CONTINUE LIKELY POPS THROUGH
MOST OF MONDAY MORNING FOR THE SE HALF. MID-LEVEL DRYING WILL SLOWLY
APPROACH THE WESTERN CWA MON AFTERNOON...BUT THE AFOREMENTIONED
FORCING ALONG WITH TONIGHTS LOW-LEVEL FRONT BEGINNING TO STALL OVER
THE FAR SOUTHERN CWA AND NORTHERN WI WILL LIKELY KEEP SOME LIGHT
RAIN ACROSS A GOOD PORTION OF THE SE CWA THROUGH THE AFTERNOON. HAVE
THUS INCREASED POPS A TOUCH THERE. AFTER A VERY WARM
WEEKEND...MONDAY WILL FEEL RATHER COOL AS TEMPS STRUGGLE TO REACH
THE 70S FOR MANY LOCATIONS UNDER CLOUDY SKIES AND NORTHERLY WINDS.
THE H7 TO H8 FRONT NEVER TRULY CLEARS THE SOUTHERN CWA DURING THE
NIGHT. THIS...AND INFLUENCE FROM THE UPPER JET STILL LINGERING NORTH
OF THE CWA MAY PRODUCE A FEW SHOWERS THROUGH THE NIGHT FOR THE SE
HALF.
TUESDAY THROUGH THURSDAY...MODEL INCONSISTENCIES HAVE PLAGUED THIS
PERIOD FOR SEVERAL DAYS NOW. THE LATEST SUITE OF MODELS DOES PROVIDE
SOME HOPE THOUGH. DEEP TROUGHING DEVELOPING OVER THE NORTHERN AND
CENTRAL HIGH PLAINS WILL INDUCE A SFC LOW OVER THE CENTRAL PLAINS
TUESDAY. THE STALLED LOW-LEVEL FRONT WILL ACT AS A WEAK FORCING
MECHANISM WITH SUBTLE ISENTROPIC LIFT AND MOISTURE RETURN SPREADING
ACROSS THE SOUTHERN CWA. PLENTY OF DRY AIR WILL HAVE INFILTRATED THE
CWA FROM THE NORTH BY THIS TIME...SO NOTHING MORE THAN A LOWERING
CLOUD DECK IS EXPECTED IN THE MORNING FOR MOST OF THE CWA. BY LATE
AFTERNOON...SOME LIGHT SHOWERS MAY BEGIN TO REACH THE SFC.
CONSIDERABLE FORCING UNDER THE LEFT-EXIT OF AN UPPER JET STREAK AND
Q-VECTOR CONV AHEAD OF THE MID-LEVEL TROUGH WILL PRODUCE A PERIOD OF
MODERATE TO POSSIBLY HEAVY RAIN ACROSS MOST OF THE CWA LATE TUESDAY
NIGHT INTO WEDNESDAY MORNING. PLACEMENT OF THE HEAVIEST QPF IS STILL
IN QUESTION...BUT AN INCH OF RAINFALL FOR A GOOD PORTION OF THE CWA
WILL NOT BE OUT OF THE QUESTION. THE MAIN LIMITING FACTOR FOR
KEEPING POPS LIKELY INSTEAD OF CATEGORICAL AT THIS POINT IS THE
POTENTIAL FOR A DRY SLOT TO QUICKLY END PRECIP WED MORNING.
AS THE SYSTEM DEPARTS...MOIST LOW-LEVEL CYCLONIC FLOW WILL KEEP
CLOUDS AND SCATTERED SHOWERS AROUND THE AREA INTO THURSDAY NIGHT.
THE GFS IS ADVERTISING A QUICK EXIT OF THE LOW...SO AN EARLIER END
TO THE PRECIP PRIOR TO THURSDAY NIGHT WILL BE POSSIBLE.
FRIDAY AND SATURDAY...WEAK MID-LEVEL RIDGING ABOVE A DEPARTING SFC
HIGH WILL ALLOW FOR MOSTLY SUNNY SKIES AND DRY CONDITIONS FOR
FRIDAY. ANOTHER STRONG TROUGH WILL DIG INTO THE NORTHERN PLAINS BY
SATURDAY. A COLD FRONT WITH THE ASSOCIATED SFC LOW OVER MANITOBA AND
SASKATCHEWAN WILL BE TRACKING ACROSS THE UPPER MS VALLEY LATE
SATURDAY...BUT SHOULD REMAIN WEST OF THE CWA DURING THE PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 212 PM EDT SUN AUG 16 2015
SINCE THE INCOMING AIRMASS IS VERY WARM AND THUS RELATIVELY
DRY...EXPECT VFR CONDITIONS TO PREDOMINATE THROUGH THIS FORECAST
PERIOD. SOME -SHRA AND PERHAPS A TS ASSOCIATED WITH A COLD FRONT
ARRIVING FROM THE W MAY IMPACT MAINLY IWD AND SAW AS EARLY AS THIS
EVNG...BUT CONFIDENCE IN THE TIMING IS TOO LOW TO GO FOR MORE THAN A
VCSH ATTM. THERE IS A BETTER CHANCE OF SHOWERS OVERNIGHT AND MON
MORNING FOR SAW AND POSSIBLY SOME ISOLD TSRA.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 524 AM EDT SUN AUG 16 2015
SOUTHWEST WINDS TO 20-25 KNOTS TODAY WILL DIMINISH AND VEER NW
TONIGHT AS A COLD FRONT MOVES THROUGH. PATCHY FOG WILL CONTINUE TO BE
POSSIBLE THROUGH TONIGHT AS HUMID AIR MOVES OVER THE COOLER WATERS
OF THE GREAT LAKES. WINDS WILL STAY AT OR BELOW 20 KNOTS THROUGH TUE
NIGHT...THEN INCREASE TO UP TO 30 KNOTS ON WED INTO EARLY THU AS THE
PRESSURE GRADIENT TIGHTENS ACROSS THE AREA WITH A STRONGER LOW
PRESSURE SYSTEM MOVING THROUGH THE REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KLUBER
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
741 AM EDT SUN AUG 16 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 518 AM EDT SUN AUG 16 2015
WV IMAGERY AND RAP ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE FROM
THE SW CONUS THROUGH THE SRN GREAT LAKES RESULTING IN WSW FLOW FROM
THE THE CNTRL ROCKIES THROUGH THE NRN LAKES. A SHORTWAVE TROUGH WAS
MOVING THROUGH CNTRL MANITOBA. AT THE SFC...SW FLOW WAS INCREASING
FROM THE UPPER MS VALLEY INTO THE NRN LAKES AHEAD OF A COLD FRONT
INTO NW MN EXTENDING FROM LOW PRES OVER NW ONTARIO. A LINE OF
SHRA/TSRA AHEAD OF THE FRONT FROM NEAR KELO INTO SW MN WAS
DIMINISHING AS IT MOVES AWAY FROM THE AXIS OF HIGHER INSTABILITY.
TODAY...EXPECT CONTINUED VERY WARM CONDITIONS AS MIXING TO 850 MB
TEMPS AROUND 20C SUPPORT HIGHS NEAR 90. SW DOWNSLOPE FLOW WILL BE
STRONG ENOUGH TO PREVENT LAKE BREEZE DEVELOPMENT OFF OF LAKE
SUPERIOR AND BRING ADDITIONAL WARMING TO LOCATIONS NEAR THE SHORE.
FORECAST SOUNDINGS SUGGEST THAT 800-700 MB CAPPING WILL BE STRONG
ENOUGH TO PREVENT SHRA/TSRA FROM DEVELOPING EXCEPT POSSIBLY LATE
OVER THE WEST AS THE FRONT AND FALLING HEIGHTS APPROACH.
TONIGHT...SOME SHRA/TSRA MAY BE POSSIBLE ALONG THE FRONT AS IT MOVES
INTO UPPER MICHIGAN DURING THE EVENING. HOWEVER...COVERAGE WILL BE
LIMITED WITH ONLY WEAK MID/UPPER LEVEL FORCING AND LOW LEVEL CONV
ALONG THE FRONT. EXPECT GREATER POTENTIAL FOR POST-FRONTAL PCPN
OVERNIGHT AS THE UPPER LEVEL JET MOVES INTO NW ONTARIO AND RIGHT
ENTRANCE UPPER LEVEL DIV AND ASSOCIATED 800-700 MB FGEN STRENGTHEN
OVER UPPER MI. THERE IS STILL SOME UNCERTAINTY WITH THE LOCATION OF
THE STRONGER FORCING AND WHERE THE HEAVIEST PCPN WILL DEVELOP. WITH
30-40 KNOT 0-6KM SHEAR...THERE WILL BE A LIMITED STRONG/SEVERE TSRA
THREAT...MAINLY DURING THE EVENING BEFORE THE MUCAPE IN THE 1K-2K
J/KG RANGE DIMINISHES. ALTHOUGH SOME STRONGER ELEVATED STORMS MAY
STILL BE POSSIBLE OVERNIGHT THAT COULD PRODUCE SOME HAIL...WITH
WEAKENING INSTABILITY THE SVR THREAT SHOULD ALSO TAPER OFF.
ACCORDINGLY...SPC HAS PUSHED THE MARGINAL RISK FARTHER TO THE SOUTH
OVER WI.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 437 AM EDT SUN AUG 16 2015
MUCH COOLER CONDITIONS ARE EXPECTED THROUGH THE UPCOMING WEEK...WITH
A COUPLE ROUNDS OF WIDESPREAD RAINFALL POSSIBLE.
MONDAY AND MONDAY NIGHT...A SHORTWAVE TROUGH WITHIN BROAD MID-LEVEL
TROUGHING ACROSS THE EAST HALF OF CANADA WILL BE EXITING THE CWA
NEAR THE START OF THE PERIOD. MEANWHILE...THE RIGHT ENTRANCE OF A
130KT UPPER JET STREAK WILL BE SITUATED ACROSS THE CENTRAL AND
EASTERN CWA. THIS WILL BE ENOUGH TO CONTINUE LIKELY POPS THROUGH
MOST OF MONDAY MORNING FOR THE SE HALF. MID-LEVEL DRYING WILL SLOWLY
APPROACH THE WESTERN CWA MON AFTERNOON...BUT THE AFOREMENTIONED
FORCING ALONG WITH TONIGHTS LOW-LEVEL FRONT BEGINNING TO STALL OVER
THE FAR SOUTHERN CWA AND NORTHERN WI WILL LIKELY KEEP SOME LIGHT
RAIN ACROSS A GOOD PORTION OF THE SE CWA THROUGH THE AFTERNOON. HAVE
THUS INCREASED POPS A TOUCH THERE. AFTER A VERY WARM
WEEKEND...MONDAY WILL FEEL RATHER COOL AS TEMPS STRUGGLE TO REACH
THE 70S FOR MANY LOCATIONS UNDER CLOUDY SKIES AND NORTHERLY WINDS.
THE H7 TO H8 FRONT NEVER TRULY CLEARS THE SOUTHERN CWA DURING THE
NIGHT. THIS...AND INFLUENCE FROM THE UPPER JET STILL LINGERING NORTH
OF THE CWA MAY PRODUCE A FEW SHOWERS THROUGH THE NIGHT FOR THE SE
HALF.
TUESDAY THROUGH THURSDAY...MODEL INCONSISTENCIES HAVE PLAGUED THIS
PERIOD FOR SEVERAL DAYS NOW. THE LATEST SUITE OF MODELS DOES PROVIDE
SOME HOPE THOUGH. DEEP TROUGHING DEVELOPING OVER THE NORTHERN AND
CENTRAL HIGH PLAINS WILL INDUCE A SFC LOW OVER THE CENTRAL PLAINS
TUESDAY. THE STALLED LOW-LEVEL FRONT WILL ACT AS A WEAK FORCING
MECHANISM WITH SUBTLE ISENTROPIC LIFT AND MOISTURE RETURN SPREADING
ACROSS THE SOUTHERN CWA. PLENTY OF DRY AIR WILL HAVE INFILTRATED THE
CWA FROM THE NORTH BY THIS TIME...SO NOTHING MORE THAN A LOWERING
CLOUD DECK IS EXPECTED IN THE MORNING FOR MOST OF THE CWA. BY LATE
AFTERNOON...SOME LIGHT SHOWERS MAY BEGIN TO REACH THE SFC.
CONSIDERABLE FORCING UNDER THE LEFT-EXIT OF AN UPPER JET STREAK AND
Q-VECTOR CONV AHEAD OF THE MID-LEVEL TROUGH WILL PRODUCE A PERIOD OF
MODERATE TO POSSIBLY HEAVY RAIN ACROSS MOST OF THE CWA LATE TUESDAY
NIGHT INTO WEDNESDAY MORNING. PLACEMENT OF THE HEAVIEST QPF IS STILL
IN QUESTION...BUT AN INCH OF RAINFALL FOR A GOOD PORTION OF THE CWA
WILL NOT BE OUT OF THE QUESTION. THE MAIN LIMITING FACTOR FOR
KEEPING POPS LIKELY INSTEAD OF CATEGORICAL AT THIS POINT IS THE
POTENTIAL FOR A DRY SLOT TO QUICKLY END PRECIP WED MORNING.
AS THE SYSTEM DEPARTS...MOIST LOW-LEVEL CYCLONIC FLOW WILL KEEP
CLOUDS AND SCATTERED SHOWERS AROUND THE AREA INTO THURSDAY NIGHT.
THE GFS IS ADVERTISING A QUICK EXIT OF THE LOW...SO AN EARLIER END
TO THE PRECIP PRIOR TO THURSDAY NIGHT WILL BE POSSIBLE.
FRIDAY AND SATURDAY...WEAK MID-LEVEL RIDGING ABOVE A DEPARTING SFC
HIGH WILL ALLOW FOR MOSTLY SUNNY SKIES AND DRY CONDITIONS FOR
FRIDAY. ANOTHER STRONG TROUGH WILL DIG INTO THE NORTHERN PLAINS BY
SATURDAY. A COLD FRONT WITH THE ASSOCIATED SFC LOW OVER MANITOBA AND
SASKATCHEWAN WILL BE TRACKING ACROSS THE UPPER MS VALLEY LATE
SATURDAY...BUT SHOULD REMAIN WEST OF THE CWA DURING THE PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 740 AM EDT SUN AUG 16 2015
SINCE THE INCOMING AIRMASS IS VERY WARM AND THUS RELATIVELY
DRY...EXPECT VFR CONDITIONS TO PREDOMINATE INTO THIS EVENING. SOME
-SHRA AND PERHAPS A TS ASSOCIATED WITH A COLD FRONT ARRIVING FROM
THE W MAY IMPACT MAINLY IWD AND SAW AS EARLY AS THIS EVNG...BUT
CONFIDENCE IN THE TIMING IS TOO LO TO GO FOR MORE THAN A VCSH ATTM.
THERE IS A BETTER CHANCE OF SHOWERS OVERNIGHT AND POSSIBLY SOME
ISOLD TSRA. CIGS ARE EXPECTED TO DROP TO MVFR AT IWD WITH INCREASING
LOW LEVEL MOISTURE BEHIND THE FRONT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 524 AM EDT SUN AUG 16 2015
SOUTHWEST WINDS TO 20-25 KNOTS TODAY WILL DIMINISH AND VEER NW
TONIGHT AS A COLD FRONT MOVES THROUGH. PATCHY FOG WILL CONTINUE TO BE
POSSIBLE THROUGH TONIGHT AS HUMID AIR MOVES OVER THE COOLER WATERS
OF THE GREAT LAKES. WINDS WILL STAY AT OR BELOW 20 KNOTS THROUGH TUE
NIGHT...THEN INCREASE TO UP TO 30 KNOTS ON WED INTO EARLY THU AS THE
PRESSURE GRADIENT TIGHTENS ACROSS THE AREA WITH A STRONGER LOW
PRESSURE SYSTEM MOVING THROUGH THE REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KLUBER
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
526 AM EDT SUN AUG 16 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 518 AM EDT SUN AUG 16 2015
WV IMAGERY AND RAP ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE FROM
THE SW CONUS THROUGH THE SRN GREAT LAKES RESULTING IN WSW FLOW FROM
THE THE CNTRL ROCKIES THROUGH THE NRN LAKES. A SHORTWAVE TROUGH WAS
MOVING THROUGH CNTRL MANITOBA. AT THE SFC...SW FLOW WAS INCREASING
FROM THE UPPER MS VALLEY INTO THE NRN LAKES AHEAD OF A COLD FRONT
INTO NW MN EXTENDING FROM LOW PRES OVER NW ONTARIO. A LINE OF
SHRA/TSRA AHEAD OF THE FRONT FROM NEAR KELO INTO SW MN WAS
DIMINISHING AS IT MOVES AWAY FROM THE AXIS OF HIGHER INSTABILITY.
TODAY...EXPECT CONTINUED VERY WARM CONDITIONS AS MIXING TO 850 MB
TEMPS AROUND 20C SUPPORT HIGHS NEAR 90. SW DOWNSLOPE FLOW WILL BE
STRONG ENOUGH TO PREVENT LAKE BREEZE DEVELOPMENT OFF OF LAKE
SUPERIOR AND BRING ADDITIONAL WARMING TO LOCATIONS NEAR THE SHORE.
FORECAST SOUNDINGS SUGGEST THAT 800-700 MB CAPPING WILL BE STRONG
ENOUGH TO PREVENT SHRA/TSRA FROM DEVELOPING EXCEPT POSSIBLY LATE
OVER THE WEST AS THE FRONT AND FALLING HEIGHTS APPROACH.
TONIGHT...SOME SHRA/TSRA MAY BE POSSIBLE ALONG THE FRONT AS IT MOVES
INTO UPPER MICHIGAN DURING THE EVENING. HOWEVER...COVERAGE WILL BE
LIMITED WITH ONLY WEAK MID/UPPER LEVEL FORCING AND LOW LEVEL CONV
ALONG THE FRONT. EXPECT GREATER POTENTIAL FOR POST-FRONTAL PCPN
OVERNIGHT AS THE UPPER LEVEL JET MOVES INTO NW ONTARIO AND RIGHT
ENTRANCE UPPER LEVEL DIV AND ASSOCIATED 800-700 MB FGEN STRENGTHEN
OVER UPPER MI. THERE IS STILL SOME UNCERTAINTY WITH THE LOCATION OF
THE STRONGER FORCING AND WHERE THE HEAVIEST PCPN WILL DEVELOP. WITH
30-40 KNOT 0-6KM SHEAR...THERE WILL BE A LIMITED STRONG/SEVERE TSRA
THREAT...MAINLY DURING THE EVENING BEFORE THE MUCAPE IN THE 1K-2K
J/KG RANGE DIMINISHES. ALTHOUGH SOME STRONGER ELEVATED STORMS MAY
STILL BE POSSIBLE OVERNIGHT THAT COULD PRODUCE SOME HAIL...WITH
WEAKENING INSTABILITY THE SVR THREAT SHOULD ALSO TAPER OFF.
ACCORDINGLY...SPC HAS PUSHED THE MARGINAL RISK FARTHER TO THE SOUTH
OVER WI.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 437 AM EDT SUN AUG 16 2015
MUCH COOLER CONDITIONS ARE EXPECTED THROUGH THE UPCOMING WEEK...WITH
A COUPLE ROUNDS OF WIDESPREAD RAINFALL POSSIBLE.
MONDAY AND MONDAY NIGHT...A SHORTWAVE TROUGH WITHIN BROAD MID-LEVEL
TROUGHING ACROSS THE EAST HALF OF CANADA WILL BE EXITING THE CWA
NEAR THE START OF THE PERIOD. MEANWHILE...THE RIGHT ENTRANCE OF A
130KT UPPER JET STREAK WILL BE SITUATED ACROSS THE CENTRAL AND
EASTERN CWA. THIS WILL BE ENOUGH TO CONTINUE LIKELY POPS THROUGH
MOST OF MONDAY MORNING FOR THE SE HALF. MID-LEVEL DRYING WILL SLOWLY
APPROACH THE WESTERN CWA MON AFTERNOON...BUT THE AFOREMENTIONED
FORCING ALONG WITH TONIGHTS LOW-LEVEL FRONT BEGINNING TO STALL OVER
THE FAR SOUTHERN CWA AND NORTHERN WI WILL LIKELY KEEP SOME LIGHT
RAIN ACROSS A GOOD PORTION OF THE SE CWA THROUGH THE AFTERNOON. HAVE
THUS INCREASED POPS A TOUCH THERE. AFTER A VERY WARM
WEEKEND...MONDAY WILL FEEL RATHER COOL AS TEMPS STRUGGLE TO REACH
THE 70S FOR MANY LOCATIONS UNDER CLOUDY SKIES AND NORTHERLY WINDS.
THE H7 TO H8 FRONT NEVER TRULY CLEARS THE SOUTHERN CWA DURING THE
NIGHT. THIS...AND INFLUENCE FROM THE UPPER JET STILL LINGERING NORTH
OF THE CWA MAY PRODUCE A FEW SHOWERS THROUGH THE NIGHT FOR THE SE
HALF.
TUESDAY THROUGH THURSDAY...MODEL INCONSISTENCIES HAVE PLAGUED THIS
PERIOD FOR SEVERAL DAYS NOW. THE LATEST SUITE OF MODELS DOES PROVIDE
SOME HOPE THOUGH. DEEP TROUGHING DEVELOPING OVER THE NORTHERN AND
CENTRAL HIGH PLAINS WILL INDUCE A SFC LOW OVER THE CENTRAL PLAINS
TUESDAY. THE STALLED LOW-LEVEL FRONT WILL ACT AS A WEAK FORCING
MECHANISM WITH SUBTLE ISENTROPIC LIFT AND MOISTURE RETURN SPREADING
ACROSS THE SOUTHERN CWA. PLENTY OF DRY AIR WILL HAVE INFILTRATED THE
CWA FROM THE NORTH BY THIS TIME...SO NOTHING MORE THAN A LOWERING
CLOUD DECK IS EXPECTED IN THE MORNING FOR MOST OF THE CWA. BY LATE
AFTERNOON...SOME LIGHT SHOWERS MAY BEGIN TO REACH THE SFC.
CONSIDERABLE FORCING UNDER THE LEFT-EXIT OF AN UPPER JET STREAK AND
Q-VECTOR CONV AHEAD OF THE MID-LEVEL TROUGH WILL PRODUCE A PERIOD OF
MODERATE TO POSSIBLY HEAVY RAIN ACROSS MOST OF THE CWA LATE TUESDAY
NIGHT INTO WEDNESDAY MORNING. PLACEMENT OF THE HEAVIEST QPF IS STILL
IN QUESTION...BUT AN INCH OF RAINFALL FOR A GOOD PORTION OF THE CWA
WILL NOT BE OUT OF THE QUESTION. THE MAIN LIMITING FACTOR FOR
KEEPING POPS LIKELY INSTEAD OF CATEGORICAL AT THIS POINT IS THE
POTENTIAL FOR A DRY SLOT TO QUICKLY END PRECIP WED MORNING.
AS THE SYSTEM DEPARTS...MOIST LOW-LEVEL CYCLONIC FLOW WILL KEEP
CLOUDS AND SCATTERED SHOWERS AROUND THE AREA INTO THURSDAY NIGHT.
THE GFS IS ADVERTISING A QUICK EXIT OF THE LOW...SO AN EARLIER END
TO THE PRECIP PRIOR TO THURSDAY NIGHT WILL BE POSSIBLE.
FRIDAY AND SATURDAY...WEAK MID-LEVEL RIDGING ABOVE A DEPARTING SFC
HIGH WILL ALLOW FOR MOSTLY SUNNY SKIES AND DRY CONDITIONS FOR
FRIDAY. ANOTHER STRONG TROUGH WILL DIG INTO THE NORTHERN PLAINS BY
SATURDAY. A COLD FRONT WITH THE ASSOCIATED SFC LOW OVER MANITOBA AND
SASKATCHEWAN WILL BE TRACKING ACROSS THE UPPER MS VALLEY LATE
SATURDAY...BUT SHOULD REMAIN WEST OF THE CWA DURING THE PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 123 AM EDT SUN AUG 16 2015
A STRENGTHENING SW FLOW OVER STABLE NEAR SFC LYR WL RESULT IN LLWS
AT ALL 3 TAF SITES EARLY THIS MRNG. DAYTIME HEATING/MIXING WL END
THE LLWS SOON AFT SUNRISE ON SUN MRNG AND RESULT IN GUSTY WINDS BY
THE AFTN. SINCE THE INCOMING AIRMASS IS VERY WARM AND THUS
RELATIVELY DRY...EXPECT VFR CONDITIONS TO PREDOMINATE THRU AT LEAST
THIS AFTN. SOME -SHRA AND PERHAPS A TS ASSOCIATED WITH A COLD FNT
ARRIVING FM THE W MAY IMPACT MAINLY IWD AND SAW AS EARLY AS THIS
EVNG...BUT CONFIDENCE IN THE TIMING IS TOO LO TO GO FOR MORE THAN A
VCSH ATTM.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 524 AM EDT SUN AUG 16 2015
SOUTHWEST WINDS TO 20-25 KNOTS TODAY WILL DIMINISH AND VEER NW
TONIGHT AS A COLD FRONT MOVES THROUGH. PATCHY FOG WILL CONTINUE TO BE
POSSIBLE THROUGH TONIGHT AS HUMID AIR MOVES OVER THE COOLER WATERS
OF THE GREAT LAKES. WINDS WILL STAY AT OR BELOW 20 KNOTS THROUGH TUE
NIGHT...THEN INCREASE TO UP TO 30 KNOTS ON WED INTO EARLY THU AS THE
PRESSURE GRADIENT TIGHTENS ACROSS THE AREA WITH A STRONGER LOW
PRESSURE SYSTEM MOVING THROUGH THE REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KLUBER
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
519 AM EDT SUN AUG 16 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 518 AM EDT SUN AUG 16 2015
WV IMAGERY AND RAP ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE FROM
THE SW CONUS THROUGH THE SRN GREAT LAKES RESULTING IN WSW FLOW FROM
THE THE CNTRL ROCKIES THROUGH THE NRN LAKES. A SHORTWAVE TROUGH WAS
MOVING THROUGH CNTRL MANITOBA. AT THE SFC...SW FLOW WAS INCREASING
FROM THE UPPER MS VALLEY INTO THE NRN LAKES AHEAD OF A COLD FRONT
INTO NW MN EXTENDING FROM LOW PRES OVER NW ONTARIO. A LINE OF
SHRA/TSRA AHEAD OF THE FRONT FROM NEAR KELO INTO SW MN WAS
DIMINISHING AS IT MOVES AWAY FROM THE AXIS OF HIGHER INSTABILITY.
TODAY...EXPECT CONTINUED VERY WARM CONDITIONS AS MIXING TO 850 MB
TEMPS AROUND 20C SUPPORT HIGHS NEAR 90. SW DOWNSLOPE FLOW WILL BE
STRONG ENOUGH TO PREVENT LAKE BREEZE DEVELOPMENT OFF OF LAKE
SUPERIOR AND BRING ADDITIONAL WARMING TO LOCATIONS NEAR THE SHORE.
FORECAST SOUNDINGS SUGGEST THAT 800-700 MB CAPPING WILL BE STRONG
ENOUGH TO PREVENT SHRA/TSRA FROM DEVELOPING EXCEPT POSSIBLY LATE
OVER THE WEST AS THE FRONT AND FALLING HEIGHTS APPROACH.
TONIGHT...SOME SHRA/TSRA MAY BE POSSIBLE ALONG THE FRONT AS IT MOVES
INTO UPPER MICHIGAN DURING THE EVENING. HOWEVER...COVERAGE WILL BE
LIMITED WITH ONLY WEAK MID/UPPER LEVEL FORCING AND LOW LEVEL CONV
ALONG THE FRONT. EXPECT GREATER POTENTIAL FOR POST-FRONTAL PCPN
OVERNIGHT AS THE UPPER LEVEL JET MOVES INTO NW ONTARIO AND RIGHT
ENTRANCE UPPER LEVEL DIV AND ASSOCIATED 800-700 MB FGEN STRENGTHEN
OVER UPPER MI. THERE IS STILL SOME UNCERTAINTY WITH THE LOCATION OF
THE STRONGER FORCING AND WHERE THE HEAVIEST PCPN WILL DEVELOP. WITH
30-40 KNOT 0-6KM SHEAR...THERE WILL BE A LIMITED STRONG/SEVERE TSRA
THREAT...MAINLY DURING THE EVENING BEFORE THE MUCAPE IN THE 1K-2K
J/KG RANGE DIMINISHES. ALTHOUGH SOME STRONGER ELEVATED STORMS MAY
STILL BE POSSIBLE OVERNIGHT THAT COULD PRODUCE SOME HAIL...WITH
WEAKENING INSTABILITY THE SVR THREAT SHOULD ALSO TAPER OFF.
ACCORDINGLY...SPC HAS PUSHED THE MARGINAL RISK FARTHER TO THE SOUTH
OVER WI.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 437 AM EDT SUN AUG 16 2015
MUCH COOLER CONDITIONS ARE EXPECTED THROUGH THE UPCOMING WEEK...WITH
A COUPLE ROUNDS OF WIDESPREAD RAINFALL POSSIBLE.
MONDAY AND MONDAY NIGHT...A SHORTWAVE TROUGH WITHIN BROAD MID-LEVEL
TROUGHING ACROSS THE EAST HALF OF CANADA WILL BE EXITING THE CWA
NEAR THE START OF THE PERIOD. MEANWHILE...THE RIGHT ENTRANCE OF A
130KT UPPER JET STREAK WILL BE SITUATED ACROSS THE CENTRAL AND
EASTERN CWA. THIS WILL BE ENOUGH TO CONTINUE LIKELY POPS THROUGH
MOST OF MONDAY MORNING FOR THE SE HALF. MID-LEVEL DRYING WILL SLOWLY
APPROACH THE WESTERN CWA MON AFTERNOON...BUT THE AFOREMENTIONED
FORCING ALONG WITH TONIGHTS LOW-LEVEL FRONT BEGINNING TO STALL OVER
THE FAR SOUTHERN CWA AND NORTHERN WI WILL LIKELY KEEP SOME LIGHT
RAIN ACROSS A GOOD PORTION OF THE SE CWA THROUGH THE AFTERNOON. HAVE
THUS INCREASED POPS A TOUCH THERE. AFTER A VERY WARM
WEEKEND...MONDAY WILL FEEL RATHER COOL AS TEMPS STRUGGLE TO REACH
THE 70S FOR MANY LOCATIONS UNDER CLOUDY SKIES AND NORTHERLY WINDS.
THE H7 TO H8 FRONT NEVER TRULY CLEARS THE SOUTHERN CWA DURING THE
NIGHT. THIS...AND INFLUENCE FROM THE UPPER JET STILL LINGERING NORTH
OF THE CWA MAY PRODUCE A FEW SHOWERS THROUGH THE NIGHT FOR THE SE
HALF.
TUESDAY THROUGH THURSDAY...MODEL INCONSISTENCIES HAVE PLAGUED THIS
PERIOD FOR SEVERAL DAYS NOW. THE LATEST SUITE OF MODELS DOES PROVIDE
SOME HOPE THOUGH. DEEP TROUGHING DEVELOPING OVER THE NORTHERN AND
CENTRAL HIGH PLAINS WILL INDUCE A SFC LOW OVER THE CENTRAL PLAINS
TUESDAY. THE STALLED LOW-LEVEL FRONT WILL ACT AS A WEAK FORCING
MECHANISM WITH SUBTLE ISENTROPIC LIFT AND MOISTURE RETURN SPREADING
ACROSS THE SOUTHERN CWA. PLENTY OF DRY AIR WILL HAVE INFILTRATED THE
CWA FROM THE NORTH BY THIS TIME...SO NOTHING MORE THAN A LOWERING
CLOUD DECK IS EXPECTED IN THE MORNING FOR MOST OF THE CWA. BY LATE
AFTERNOON...SOME LIGHT SHOWERS MAY BEGIN TO REACH THE SFC.
CONSIDERABLE FORCING UNDER THE LEFT-EXIT OF AN UPPER JET STREAK AND
Q-VECTOR CONV AHEAD OF THE MID-LEVEL TROUGH WILL PRODUCE A PERIOD OF
MODERATE TO POSSIBLY HEAVY RAIN ACROSS MOST OF THE CWA LATE TUESDAY
NIGHT INTO WEDNESDAY MORNING. PLACEMENT OF THE HEAVIEST QPF IS STILL
IN QUESTION...BUT AN INCH OF RAINFALL FOR A GOOD PORTION OF THE CWA
WILL NOT BE OUT OF THE QUESTION. THE MAIN LIMITING FACTOR FOR
KEEPING POPS LIKELY INSTEAD OF CATEGORICAL AT THIS POINT IS THE
POTENTIAL FOR A DRY SLOT TO QUICKLY END PRECIP WED MORNING.
AS THE SYSTEM DEPARTS...MOIST LOW-LEVEL CYCLONIC FLOW WILL KEEP
CLOUDS AND SCATTERED SHOWERS AROUND THE AREA INTO THURSDAY NIGHT.
THE GFS IS ADVERTISING A QUICK EXIT OF THE LOW...SO AN EARLIER END
TO THE PRECIP PRIOR TO THURSDAY NIGHT WILL BE POSSIBLE.
FRIDAY AND SATURDAY...WEAK MID-LEVEL RIDGING ABOVE A DEPARTING SFC
HIGH WILL ALLOW FOR MOSTLY SUNNY SKIES AND DRY CONDITIONS FOR
FRIDAY. ANOTHER STRONG TROUGH WILL DIG INTO THE NORTHERN PLAINS BY
SATURDAY. A COLD FRONT WITH THE ASSOCIATED SFC LOW OVER MANITOBA AND
SASKATCHEWAN WILL BE TRACKING ACROSS THE UPPER MS VALLEY LATE
SATURDAY...BUT SHOULD REMAIN WEST OF THE CWA DURING THE PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 123 AM EDT SUN AUG 16 2015
A STRENGTHENING SW FLOW OVER STABLE NEAR SFC LYR WL RESULT IN LLWS
AT ALL 3 TAF SITES EARLY THIS MRNG. DAYTIME HEATING/MIXING WL END
THE LLWS SOON AFT SUNRISE ON SUN MRNG AND RESULT IN GUSTY WINDS BY
THE AFTN. SINCE THE INCOMING AIRMASS IS VERY WARM AND THUS
RELATIVELY DRY...EXPECT VFR CONDITIONS TO PREDOMINATE THRU AT LEAST
THIS AFTN. SOME -SHRA AND PERHAPS A TS ASSOCIATED WITH A COLD FNT
ARRIVING FM THE W MAY IMPACT MAINLY IWD AND SAW AS EARLY AS THIS
EVNG...BUT CONFIDENCE IN THE TIMING IS TOO LO TO GO FOR MORE THAN A
VCSH ATTM.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 250 PM EDT SAT AUG 15 2015
FOG WILL CONTINUE TO BE POSSIBLE OVER THE WATERS THROUGH SUN NIGHT
AS HUMID AIR MOVES OVER THE COLDER WATERS OF THE GREAT LAKES AND
COULD SEE PATCHY TO AREAS OF FOG THROUGH THEN. WINDS WILL STAY AT OR
BELOW 20 KNOTS THROUGH TUE NIGHT...THEN INCREASE TO UP TO 30 KNOTS
ON WED THROUGH THU AS THE PRESSURE GRADIENT TIGHTENS ACROSS THE AREA
WITH A STRONGER LOW PRESSURE SYSTEM MOVING BY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KLUBER
AVIATION...JLB
MARINE...07
AREA FORECAST DISCUSSION
NWS GAYLORD MI
204 AM EDT SUN AUG 16 2015
.UPDATE...
ISSUED AT 1007 PM EDT SAT AUG 15 2015
...QUIET AND MILD OVERNIGHT...
UPPER LEVEL RIDGING ENCOMPASSES MUCH OF THE CONUS THIS EVENING
WITH AXIS OF >588 DM 500 MB HEIGHTS STRETCHING FROM THE PLAINS
ACROSS THE GREAT LAKES. MAIN UPPER JET HAS BEEN SHUNTED INTO THE
NRN PLAINS INTO SRN CANADA NORTH OF THE "HEAT DOME." AT THE
SFC...BROAD HIGH PRESSURE REMAINS ACROSS MUCH OF THE EASTERN
CONUS. LOW PRESSURE SYSTEM NOTED JUST NORTH OF THE US-CANADIAN
BORDER NORTH OF THE DAKOTAS WITH A WARM FRONT STRETCHING THROUGH
CENTRAL ONTARIO AND COLD FRONT DOWN THROUGH THE PLAINS. SEVERAL
BATCHES OF SHOWERS AND SOME THUNDERSTORMS ARE UNDERWAY ACROSS
ONTARIO ALONG THE WARM FRONT WITH SOME OF THE HIGH LEVEL CIRRUS
SPILLING INTO NRN MICHIGAN. EARLIER BUBBLY CU FIELD ACROSS NRN
LOWER MICHIGAN (AND VERY SPOTTY SHOWER WANNABES) HAS PRETTY MUCH
FADED WITH JUST A FEW CLOUDS REMAINING DOWN AROUND TVC/CAD.
OVERNIGHT...AFOREMENTIONED SFC LOW NORTH OF THE DAKOTAS WILL
TRAVEL NORTHEASTWARD INTO CENTRAL ONTARIO BY MORNING WHILE SFC
COLD FRONT GETS STRETCHED OUT BACK INTO THE NRN PLAINS...WELL
NORTH OF THE STATE AND WHERE THE ACTIVE WEATHER WILL REMAIN. FOR
US...WILL CONTINUE TO SEE SOME THICKER CIRRUS INVADE THE NRN PARTS
OF THE CWA THROUGH THE NIGHT WITH OVERALL PARTLY CLOUDY CONDITIONS
IN THE U.P. MAINLY CLEAR TO THE SOUTH (HOPEFULLY). DON/T THINK
FOG WILL BE MUCH OF AN ISSUE TONIGHT WITH SLIGHTLY LOWER SFC
DEWPOINTS AND GOOD MIXING DURING THE DAY. THAT SAID...AN
INTERESTING NOTE...NAM AND HRRR SOLUTIONS BOTH SUGGEST AN
EXPANDING LOW CLOUD LAYER OFF THE LAKE INTO NW LOWER MICHIGAN
OVERNIGHT AS SW FLOW BEGINS TO INCREASE AND DRAGS HIGHER LOW LEVEL
DEWPOINT AIR OUT OF WISCONSIN UP INTO THE REGION. HAVE CAUTIOUSLY
IGNORED THAT IDEA FOR THE MOMENT...BUT WILL SEE WHAT HAPPENS.
HERES HOPING I DON/T WAKE TOMORROW MORNING TO A SUNRISE SURPRISE
STRATUS DECK.
&&
.NEAR TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 325 PM EDT SAT AUG 15 2015
HIGH IMPACT WEATHER POTENTIAL: A ROGUE EVENING SHOWER OR STORM (OR
TWO) STILL POSSIBLE...WITH ANY STORMS BEING VERY SLOW MOVERS.
ALL REMAINS RATHER QUIET AT THE MOMENT ACROSS NORTHERN MICHIGAN...
WITH PRONOUNCED UPPER RIDGING (590 DM HEIGHTS) FOLDING IN FROM THE
NORTHWEST...WHILE LOW LEVEL RIDGING RESIDES ALL THROUGHOUT THE
OHIO/TENNESSEE VALLEYS. OUR AIRMASS REMAINS A RATHER HOT ONE BY
NORTHERN MICHIGAN STANDARDS...WITH TEMPS A FEW DEGREES EITHER SIDE
OF 90 AS OF 19Z...WHILE DEW POINTS ARE A TOUCH MORE "COMFORTABLE"
DOWN IN THE 60S...THOUGH LOCALLY HIGHER RIGHT NEAR THE LAKE SHORES
WHERE WINDS HAVE TURNED ONSHORE. STRONG INLAND THERMAL TROUGH
DEVELOPMENT IS NOTED PER MESOANALYSIS...WITH A CONVERGENCE BULLSEYE
INCHING TOWARD THE HIGHER TERRAIN...AS IS TYPICAL ON VERY LIGHT WIND
REGIME DAYS. HAVE SEEN A DECENT FLARE UP OF CU WITHIN THE BETTER
HEATING/MOISTURE CONVERGENCE ALONG THIS AXIS...THOUGH WITH NO
NOTABLE RADAR RETURNS AS OF YET...COURTESY OF A CAP JUST UNDER 700MB
PER 12Z APX RAOB.
IN THEORY...WE STILL HAVE A SHOT AT A COUPLE SHOWERS/STORMS FIRING
OFF THROUGH LATE AFTERNOON AND EARLY EVENING...AND INDEED THE
FORECAST WILL CONTINUE TO REFLECT THAT IDEA. AS MENTIONED
EARLIER...WITH BASICALLY NIL STEERING FLOW BELOW 500MB (SOMETHING
LIKE A WHOPPING 8 KNOTS!)...ANY CONVECTION THAT DOES FIRE WILL BOTH
BE SLOW MOVING WITH A LOCAL HEAVY RAIN THREAT (SKINNY CAPE/HIGH
FREEZING LEVELS) AS WELL AS A PROLIFIC OUTFLOW BOUNDARY
PRODUCER...WHICH IN TURN MAY TRY TO SET OFF A FEW ADDITIONAL
CONVECTIVE CELLS. SOMETHING TO CONTINUE WATCHING THE NEXT FEW
HOURS...BUT DON`T FORESEE ANYTHING MORE THAN ISOLATED WORDING.
LOOKING RATHER QUIET FOR TONIGHT AS UPPER RIDGING CONTINUES TO FOLD
OVERHEAD...ALL WHILE THE BOUNDARY LAYER FLOW REGIME GRADUALLY
RESPONDS TO A TIGHTENING GRADIENT. UNLIKE LAST NIGHT...DON`T FORESEE
WIDESPREAD FOG DEVELOPMENT GIVEN BETTER MIXING OF MOISTURE
TODAY...THOUGH WHERE WINDS DECOUPLE AFTER SUNSET...SOME SHALLOW
GROUND FOG IS CERTAINLY POSSIBLE. STRONGER RETURN FLOW DEVELOPING
AFTER 07Z SHOULD PUT THE KIBOSH ON THAT...WHILE ALSO HELPING
TRANSPORT A CURRENT PLUME OF LOWER CLOUDS OVER LAKE MICHIGAN NORTH
AND OUR OF OUR HAIR. LOWS OVERNIGHT MORE MILD THAN LAST...WITH
READINGS MAINLY STUCK IN THE 60S.
&&
.SHORT TERM...(SUNDAY THROUGH TUESDAY)
ISSUED AT 325 PM EDT SAT AUG 15 2015
STRONG SURFACE HIGH CENTER SHIFTS JUST SE OF MICHIGAN ON SUNDAY...AS
THE 500 MB RIDGE AXIS LEANS SOUTHWARD INTO SRN LWR MICHIGAN. LOW
LEVEL FLOW WILL SHIFT TO THE SW AND STRENGTHEN A BIT...PUSHING EVEN
WARMER AIR INTO MICHIGAN AHEAD OF AN APPROACHING COOL FRONT. 850 MB
TEMPS SOAR TO AROUND +22 C BY SUNDAY AFTERNOON...WHICH WILL LIKELY
TRANSLATE TO HIGH TEMPS IN THE LOW TO MID 90S. WE MAY EVEN SEE A FEW
SPOTS REACH THE UPPER 90S IN ERN SECTIONS OF OUR CWA THANKS TO
DOWNSLOPING. FURTHER WARMING ALOFT WILL LIKELY CAP ANY POTENTIAL FOR
CONVECTIVE DEVELOPMENT. WE MAY NOT EVEN SEE MUCH CU DEVELOPMENT ON
SUNDAY...MUCH LESS SHOWER/STORM DEVELOPMENT. SO...FOR THOSE WHO ARE
LOOKING FOR THAT QUINTESSENTIAL HOT AND SUNNY SUMMER DAY...SUNDAY IS
IT!
OUR CWA WILL LIKELY STAY PRECIP-FREE THRU SUNDAY EVENING BEFORE WX
BECOMES ACTIVE AGAIN AS AN UPSTREAM COOL FRONT LEANS INTO NW
SECTIONS OF OUR CWA OVERNIGHT. FRONT ITSELF WILL SLOW LATE SUNDAY
NIGHT AS THE VERTICAL WIND PROFILE BECOME NEARLY UNIDIRECTIONAL...
LIKELY STALLING OVER OUR AREA THRU MID WEEK AS SEVERAL WAVES DEVELOP
ALONG THE BOUNDARY AND RIDE NE THRU MICHIGAN. CURRENTLY TOO FAR OUT
TO PROVIDE SPECIFIC TIMING ON EACH WAVE...AND CERTAINLY CONVECTIVE
POTENTIAL WILL INCREASE WITH DIURNAL HEATING/INSTABILITY. AT THIS
POINT...EXPECT SUFFICIENT MOISTURE AND INSTABILITY WILL POOL ALONG
THE FRONT...PROVIDING MUCH OF OUR CWA WILL INCREASING CHANCES OF
SHOWERS AND STORMS BEGINNING LATE SUNDAY NIGHT AND CONTINUING THRU
MONDAY AND INTO TUESDAY AS THE FRONT STALLS AND WAVES RIPPLE ALONG
IT. LOW/MID LEVEL COOLING ALONG THE FRONT WILL NOT ONLY INCREASE
INSTABILITY ALOFT...BUT WILL PROVIDE SOME PROGRESSIVE MODERATION OF
SURFACE TEMPS DURING THE FIRST PART OF THE WORK WEEK. HIGH TEMPS ON
MONDAY WILL RANGE FROM THE MID 70S IN ERN UPR MICHIGAN TO THE LOW TO
MID 80S FOR MUCH OF NRN LWR MICHIGAN. HIGHS ON TUESDAY WILL BE
MAINLY IN THE 70S THROUGHOUT OUR CWA.
&&
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 325 PM EDT SAT AUG 15 2015
HIGH IMPACT WEATHER POTENTIAL: SHOWER/THUNDERSTORM CHANCES TUESDAY
NIGHT-THURSDAY (PERHAPS STRONG-SEVERE LATE WEDNESDAY-WEDNESDAY
NIGHT).
FAIRLY DECENT MEDIUM-RANGE GUIDANCE AGREEMENT THAT A DEEPENING LOW
PRESSURE SYSTEM WILL IMPACT THE GREAT LAKES REGION BY MIDWEEK.
HOWEVER...THE ENVELOPE OF SMALL SCALE DETAILS BEGINS TO SPREAD AS
EARLY AS TUESDAY NIGHT. 15/12Z GFS IS CLEARLY THE MOST AMPLIFIED
WITH THE 15/12Z ECMWF/GEM LAGGING BEHIND IN TERMS OF OVERALL
STRENGTH AND TIMING. WILL ATTEMPT TO SOMEWHAT TAKE A BLEND OF THE
THREE...KNOWING FULL WELL THE DETAILS WILL LIKELY CHANGE IN THE
COMING DAYS.
A WARM FRONT IS EXPECTED TO BE DRAPED ACROSS EASTERN UPPER/SOUTHERN
ONTARIO BY WEDNESDAY MORNING AS LOW PRESSURE GRADUALLY DEEPENS OVER
THE PLAINS. DURING THE DAY WEDNESDAY...AN AMPLIFIED WAVE ALOFT AND
ASSOCIATED 999 MB SFC LOW BECOME CENTERED OVER EASTERN MN/WESTERN WI
BEFORE NEGATIVELY TILTING ALOFT AND SHIFTING NORTHEASTWARD TOWARD
SOUTHERN ONTARIO WEDNESDAY EVENING. AGAIN...WHILE THE ALL-IMPORTANT
TIMING REMAINS AN UNCERTAINTY...AN ASSOCIATED COLD FRONT IS EXPECTED
TO CROSS NRN MICHIGAN LATE WEDNESDAY AFTERNOON/NIGHT WITH ROUGHLY 50-
60 KTS AT 500 MB...~700-1300 J/KG OF MLCAPE AND 30-40 KTS OF 0-6 KM
BULK SHEAR PRIOR TO FROPA. THIS WOULD SUGGEST THERE`S A POTENTIAL
THAT MICHIGAN COULD ONCE AGAIN GET BACK IN ON THE SEVERE WEATHER
ACTION. NOTE SPC`S DAY 5 OUTLOOK WITH AN AREA FROM THE UPPER
PENINSULA/CANADA BORDER SOUTHWARD INTO ARKANSAS BEING HIGHLIGHTED
FOR THE POTENTIAL FOR AT LEAST SCATTERED SEVERE STORMS. WITH ALL
THIS SAID AND THE OVERALL DYNAMICS OF THE SYSTEM LINING UP WELL ON
PAPER...NORTHERN MICHIGAN`S SENSIBLE WEATHER WILL CERTAINLY DEPEND
ON THE OVERALL STRENGTH OF THE SYSTEM (SEVERAL ENSEMBLE MEMBERS
CONTINUE TO HINT AT A MUCH LESS AMPLIFIED SOLUTION) AND OF COURSE
FROPA TIMING. DEFINITELY WORTH KEEPING AN EYE ON OVER THE NEXT 4-5
DAYS.
BEYOND WEDNESDAY NIGHT...COULD SEE A BIT OF WRAP AROUND
MOISTURE/CLOUDS ACROSS AT LEAST NORTHWEST LOWER THROUGH THE DAY
THURSDAY BEFORE HIGH PRESSURE MOVES IN THE MIDWEST/GREAT LAKES
THURSDAY NIGHT THROUGH SATURDAY MORNING...ULTIMATELY RETURNING THE
REGION TO DRY WEATHER. LATE SATURDAY/SATURDAY NIGHT...ANOTHER SYSTEM
APPROACHES FROM THE WEST PERHAPS BRINGING MORE SHOWERS TO THE AREA.
THROUGHOUT THE PERIOD...LOW TEMPERATURES ARE EXPECTED TO BOTTOM OUT
A COUPLE DEGREES ON EITHER SIDE OF 60 WITH HIGH TEMPERATURES TOPPING
OUT IN THE MID-UPPER 70 (GENERALLY WITHIN A COUPLE DEGREES OF THE 76-
77 DEGREE NORMALS FOR THE THIRD WEEK IN AUGUST).
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1110 PM EDT SAT AUG 15 2015
...VFR CONDITIONS LARGELY ANTICIPATED THROUGH THE NEXT 24
HOURS...
SOME THICKER HIGH CLOUD WILL BE STREAMING ACROSS THE NRN PORTIONS
OF NRN LOWER MICHIGAN OVERNIGHT INTO SUNDAY. ALSO...INCREASING SW
FLOW TOWARD MORNING MIGHT RESULT IN SOME EXPANDING STRATUS INTO
PARTS OF NW LOWER MICHIGAN. CONFIDENCE IN THIS OCCURRING IS NOT
HIGH...BUT HAVE INCLUDED SOME SCT LOWER CLOUDS IN THE TVC/MBL
TAFS.
ON SUNDAY...SW WINDS WILL INCREASE QUICKLY DURING THE MORNING
WITH GUSTS TO AROUND 20 KNOTS DEVELOPING BY EARLY AFTERNOON. VFR
CONDITIONS WILL PERSIST ALONG WITH SCT HEATING OF THE DAY CLOUDS
DEVELOPING. WINDS DIMINISH QUICKLY SUNDAY EVENING.
&&
.MARINE...
ISSUED AT 204 AM EDT SUN AUG 16 2015
A COLD FRONT DRIVES THROUGH THE LAKES LATE TONIGHT INTO MONDAY
BRINGING A CHANCE FOR SHOWERS AND THUNDERSTORMS. OUT AHEAD OF THE
FRONT...ADVISORY LEVEL SW WINDS ARE EXPECTED TO DEVELOP OVER LAKE
MICHIGAN...AND CONTINUE THROUGH THIS EVENING. THE PRESSURE
GRADIENT SLACKENS INTO MONDAY WHILE WINDS SHIFT MORE OUT OF THE
NW THROUGH THE DAY BEHIND THE FRONT. THE FRONT MAY STALL OUT
ACROSS THE SAGINAW BAY REGION THROUGH TUESDAY...RESULTING IN MORE
VARIABLE WIND DIRECTIONS THERE. THIS ALSO MEANS THAT CHANCES FOR
SHOWERS AND STORMS WILL LINGER ACROSS MUCH OF THE REGION.
A STRONGER STORM SYSTEM IS POSSIBLE TUESDAY NIGHT INTO WEDNESDAY
WITH LOW CONFIDENCE ON WIND DIRECTIONS/SPEEDS...BUT CHANCES FOR
SHOWERS AND STORMS ARE REAL GOOD.
A ROUND OF TWO OF SHOWERS
AND THUNDERSTORMS IS POSSIBLE OVER JUST ABOUT ALL THE WATERS LATE
SUNDAY NIGHT INTO MONDAY AS THAT FRONT ARRIVES...WITH ADDITIONAL
CHANCES FOR SHOWERS AND STORMS EXPECTED INTO MID AND LATE WEEK. IN
ADDITION...THERE ARE INCREASING SIGNS THAT A FAIRLY POTENT STORM
SYSTEM MAY IMPACT NORTHERN MICHIGAN TOWARD MIDWEEK...WITH AT LEAST
THE POSSIBILITY FOR SOME GALE FORCE WINDS. STAY TUNED...
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...SMALL CRAFT ADVISORY FROM NOON TODAY TO 2 AM EDT MONDAY FOR
LMZ323-341-342-344>346.
LS...NONE.
&&
$$
UPDATE...ADAM
NEAR TERM...LAWRENCE
SHORT TERM...MLR
LONG TERM...GILLEN
AVIATION...ADAM
MARINE...SMD
AREA FORECAST DISCUSSION
NWS DULUTH MN
105 PM CDT SUN AUG 16 2015
.UPDATE...
ISSUED AT 105 PM CDT SUN AUG 16 2015
REFINED THE PROBABILITY OF SHOWERS AND THUNDERSTORMS FOR THE REST
OF THE AFTERNOON. SOME ACTIVITY IS FORMING OVER THE WESTERN EDGE
OF THE REGION IN AN AREA OF 700-400MB DIFFERENTIAL VORTICITY
ADVECTION AND DECREASING MUCIN. MAINTAINED THE MENTION ALONG THE
SOUTHERN TIER WHERE MUCAPE IS NEAR 1000 J/KG...BUT MUCIN IS STILL
HANGING TOUGH. INCREASED CLOUD COVER OVER MOST OF THE REGION AS
CLOUDS ARE STREAMING IN FROM THE SW. LEFT MAX TEMPS AS IS.
UPDATE ISSUED AT 931 AM CDT SUN AUG 16 2015
A BRIEF BREAK IN THE CLOUD COVER THIS MORNING BEFORE MORE CLOUDS
WILL ROLL BACK IN. THE COLD FRONT EXTENDS FROM NEAR CKC TO HZX AT
14Z. SOUTHERLY FLOW AHEAD OF THE FRONT AND A WEST WIND BEHIND THE
FRONT. PLENTY OF INSTABILITY AROUND...BUT MUCIN IS KEEPING ANY
STORMS FROM FIRING. DID INTRODUCE SOME POPS FOR LATE THIS MORNING
IN NW WI AS RAIN IS ATTEMPTING TO GET GOING. ADDED SOME POPS FOR
THE FAR WESTERN EDGE OF THE AREA WHERE THERE IS NO MUCIN...BUT
NOT MUCH CAPE ATTM EITHER. HIRES MODELS INCLUDING THE HRRR AND NMM
INDICATING SOME DEVELOPMENT POSSIBLE IN THIS AREA.
UPDATE ISSUED AT 738 AM CDT SUN AUG 16 2015
SHOWERS HAVE DISSIPATED. UPDATED TO TAKE OUT MENTION OF
THUNDERSTORMS UNTIL THIS AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 337 AM CDT SUN AUG 16 2015
THIS SHORT TERM PERIOD WILL FOCUS ON A COLD FRONT CURRENTLY OVER
NORTHWESTERN MN. A STRONG LOW LEVEL JET AHEAD OF THE COLD FRONT
WAS MEASURED AT 45 KTS AT 3 K FEET AS DEPICTED ON KDLH VAD WIND
PROFILE. THIS JET WAS PUSHING WARM AND MOIST AIR INTO THE
REGION...AND HELPING FUEL THUNDERSTORMS. THE STORMS HAVE DECREASED
IN INTENSITY AS THEY PUSH FARTHER AHEAD OF THE COLD FRONT AND INTO
MORE STABLE AIR. WITH MORE MOISTURE AND HEAT TRANSPORT AHEAD OF
THE FRONT TODAY...EXPECT MORE STORMS TO DEVELOP ALONG AND AHEAD OF
IT...BUT WITH THE LINGER CLOUD COVER FROM THE OVERNIGHT
MCS...STORMS MAY TAKE A WHILE TO DEVELOP. BY NOON THE FRONT SHOULD
BE FROM ABOUT ELY TO BRAINERD...EXPECT THE BULK OF ANY STORMS EAST
OF THE FRONT...WHERE A COMBINATION OF FRONTAL FORCING AND AN UPPER
LEVEL WAVE WILL HELP FORM MORE STORMS. WITH THE FRONT PASSING INTO
NORTHWESTERN WISCONSIN AT THE PEAK OF DAYTIME HEATING AND
INCREASING AFTERNOON INSTABILITY WILL MEAN SOME STRONG STORMS.
WITH WIND SHEAR LACKING ...NORTHWESTERN WI IS IN MARGINAL SEVERE
CATEGORY. THERE IS A THREAT OF HAIL AS UVM IS AIDED THE IN HIGH
CAPE ATMOSPHERE OF OVER 3000 J/KG BY ANOTHER STRONG UPPER WAVE.THE
FRONT WILL EXIT NORTHWEST WISCONSIN LATE TONIGHT. HIGH PRESSURE
WILL BUILD INTO THE NORTHLAND MONDAY. THE COLDER AIR BROUGHT WITH
THE FRONT WILL MAKE FOR A COOLER AND DRIER DAY. COLD AIR BROUGHT T
IN BEHIND THE FRONT WILL BRING 8H TEMPS DOWN TO 6 ABOVE IN
NORTHERN MN. THIS IS MUCH COOLER COMPARED TO THE THE 20C MEASURED
DURING THE 00Z RADIOSONDE DATA AT INL.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 337 AM CDT SUN AUG 16 2015
BEGINNING OF THE EXTENDED PERIOD WILL BE DRY AND DEFINED BY AN AREA
OF HIGH PRESSURE OVER NRN MN AND WRN LAKE SUPERIOR. HOWEVER...THIS
REGIME WILL BE SHORT-LIVED AND REPLACE BY AN ACTIVE/WET PERIOD LATE
TUESDAY THROUGH LATE WED NIGHT/EARLY THURSDAY. AN UPPER LEVEL S/W
WILL DIG EWD THROUGH THE NRN PLAINS AND UPPER MIDWEST DURING THIS
TIME AND LINK UP WITH A DEEPENING SFC LOW OVER THE CENTRAL PLAINS.
AS THIS SFC LOW DEVELOPS A SURGE OF MOIST AIR WILL BE ADVECTED NWD
AHEAD OF THE SYSTEM AND ALLOW CONDITIONS TO BECOME CONDUCIVE FOR
WIDESPREAD RAIN SHOWERS AND SCATTERED THUNDERSTORMS. THE MAIN
CONCERN WITH THIS BROAD SYSTEM WILL BE THE POTENTIAL FOR HEAVY
RAINFALL. THE AIR MASS WILL BE MUCH COOLER AND MORE STABLE...BUT
MUCH MORE RICH WITH MOISTURE. PWATS OVER AN INCH ARE LIKELY. THERE
IS SOME DIFFERENCES AMONG MODELS WITH THE TRACK OF THE SFC LOW WITH
THE GFS BEING THE MOST NWD...TAKING THE LOW INTO NRN WI...AND THE
MOST AGGRESSIVE WITH THE QPF OVER THE NORTHLAND. THE NAM OUTPUT HAS
THE MOST SLY TRACK OF THE LOW THROUGH THE QUAD CITIES AND INTO LAKE
MICHIGAN. THE ECMWF AND GEM SOLUTIONS ARE IN THE MIDDLE. THE
RESULTING RAINFALL AMTS WILL BE HIGHLY DEPENDENT ON THE TRACK OF THE
LOW...SO WILL KEEP MONITORING THE TRENDS OF MODEL OUTPUT THROUGH THE
NEXT 36 HOURS. WIDESPREAD RAIN AMTS AROUND 1 INCH ARE POSSIBLE WITH
LOCALLY HIGHER TOTALS NOT OUT OF THE QUESTION. AT THIS TIME IN
APPEARS THE HIGHEST AMTS COULD END UP ACROSS NRN WI.
AS THE SYSTEM WRAPS UP ON THURSDAY ACROSS THE NRN GREAT LAKES A PUSH
OF COOL AIR ON THE BACK SIDE OF THE SYSTEM COULD STEEPEN LAPSE RATES
ENOUGH TO TRIGGER POST-FRONTAL SHOWERS AND STORMS OVER THE
NORTHLAND. HOWEVER...THE OVERALL TREND LATE THURSDAY WILL BE DRYING
AS HIGH PRESSURE BUILDS IN FROM THE WEST. WEAK RIDGING ALOFT COMBINE
WITH A SFC RIDGE AXIS SLOWLY MOVING ACROSS THE UPPER MIDWEST WILL
KEEP WEATHER CONDITIONS QUIET GOING INTO THE WEEKEND. TEMPERATURES
WILL WARM LATE IN THE PERIOD WITH INCREASING HUMIDITY AS WELL. THESE
CONDITIONS WILL DESTABILIZE THE ATMOSPHERE AND ALLOW FOR A SLIGHT
CHANCE OF SHOWERS AND STORMS...BUT THE GENERALLY OUTLOOK IS DRY LATE
IN THE EXTENDED PERIOD.
TUESDAY AND WEDNESDAY STILL APPEAR TO BE THE COOLEST DAYS OF THE
WEEK WITH A MODEST E/NE WIND OFF LAKE SUPERIOR AND CAA ON-GOING
BEHIND THE FRONT. HIGHS TUE AND WED WILL ONLY REACH INTO THE 60S AND
LOWER 70S WITH NIGHT TIME LOWS IN THE 40S AND 50S. TEMPERATURES WILL
GRADUALLY WARM INTO THE MID TO UPPER 70S THROUGH THE REST OF THE
WEEK WITH OVERNIGHT LOWS IN THE 50S AND LOWER 60S.&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1227 AM CDT SUN AUG 16 2015
A COLD FRONT PUSHING INTO WESTERN MINNESOTA WILL CONTINUE TO BE
THE FOCUS FOR SHOWERS AND THUNDERSTORMS AS THE NIGHT WEARS ON.
SOME OF THE STORMS MAY BE STRONG...ESPECIALLY IN THE KBRD
AREA...WHERE GUSTY WINDS AND SMALL HAIL WILL BE POSSIBLE. THE
SHOWERS AND STORMS WILL BE IN A FAIRLY NARROW CORRIDOR...AND THE
MAIN THREAT IN ANY OF THE TAF SITES THROUGH THE NIGHT AND INTO
MORNING WILL BE A COUPLE HOURS. CONDITIONS WILL THEN IMPROVE
DURING THE DAY SUNDAY...AS THE COLD FRONT STALLS OUT IN NW WI. THE
STALLED OUT FRONT...ALONG WITH A WEAK SYSTEM MOVING ALONG THE
FRONT...WILL SET THE STAGE FOR MORE SHOWER AND THUNDERSTORM
DEVELOPMENT IN THE SOUTH AND EASTERN TAF SITES LATER IN THE DAY
AND INTO THE EVENING. THE BEST CHANCE OF PRECIPITATION DURING THAT
TIME PERIOD WILL BE IN THE KHYR AREA...WHERE SOME STRONG STORMS
WILL BE POSSIBLE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1227 AM CDT SUN AUG 16 2015
A COLD FRONT PUSHING INTO WESTERN MINNESOTA WILL CONTINUE TO BE
THE FOCUS FOR SHOWERS AND THUNDERSTORMS AS THE NIGHT WEARS ON.
SOME OF THE STORMS MAY BE STRONG...ESPECIALLY IN THE KBRD
AREA...WHERE GUSTY WINDS AND SMALL HAIL WILL BE POSSIBLE. THE
SHOWERS AND STORMS WILL BE IN A FAIRLY NARROW CORRIDOR...AND THE
MAIN THREAT IN ANY OF THE TAF SITES THROUGH THE NIGHT AND INTO
MORNING WILL BE A COUPLE HOURS. CONDITIONS WILL THEN IMPROVE
DURING THE DAY SUNDAY...AS THE COLD FRONT STALLS OUT IN NW WI. THE
STALLED OUT FRONT...ALONG WITH A WEAK SYSTEM MOVING ALONG THE
FRONT...WILL SET THE STAGE FOR MORE SHOWER AND THUNDERSTORM
DEVELOPMENT IN THE SOUTH AND EASTERN TAF SITES LATER IN THE DAY
AND INTO THE EVENING. THE BEST CHANCE OF PRECIPITATION DURING THAT
TIME PERIOD WILL BE IN THE KHYR AREA...WHERE SOME STRONG STORMS
WILL BE POSSIBLE.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 59 73 53 61 / 10 10 10 30
INL 49 68 43 71 / 0 10 0 10
BRD 58 73 52 70 / 10 10 10 40
HYR 60 73 51 70 / 60 20 10 40
ASX 60 72 53 70 / 30 10 10 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...NONE.
&&
$$
UPDATE...GSF
SHORT TERM...CLC
LONG TERM...BJT
AVIATION...MILLER
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
100 PM CDT SUN AUG 16 2015
.UPDATE...
ISSUED AT 100 PM CDT SUN AUG 16 2015
UPDATED AVIATION DISCUSSION BELOW FOR 18Z TAF ISSUANCE.
UPDATE ISSUED AT 931 AM CDT SUN AUG 16 2015
A BRIEF BREAK IN THE CLOUD COVER THIS MORNING BEFORE MORE CLOUDS
WILL ROLL BACK IN. THE COLD FRONT EXTENDS FROM NEAR CKC TO HZX AT
14Z. SOUTHERLY FLOW AHEAD OF THE FRONT AND A WEST WIND BEHIND THE
FRONT. PLENTY OF INSTABILITY AROUND...BUT MUCIN IS KEEPING ANY
STORMS FROM FIRING. DID INTRODUCE SOME POPS FOR LATE THIS MORNING
IN NW WI AS RAIN IS ATTEMPTING TO GET GOING. ADDED SOME POPS FOR
THE FAR WESTERN EDGE OF THE AREA WHERE THERE IS NO MUCIN...BUT
NOT MUCH CAPE ATTM EITHER. HIRES MODELS INCLUDING THE HRRR AND NMM
INDICATING SOME DEVELOPMENT POSSIBLE IN THIS AREA.
UPDATE ISSUED AT 738 AM CDT SUN AUG 16 2015
SHOWERS HAVE DISSIPATED. UPDATED TO TAKE OUT MENTION OF
THUNDERSTORMS UNTIL THIS AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 337 AM CDT SUN AUG 16 2015
THIS SHORT TERM PERIOD WILL FOCUS ON A COLD FRONT CURRENTLY OVER
NORTHWESTERN MN. A STRONG LOW LEVEL JET AHEAD OF THE COLD FRONT
WAS MEASURED AT 45 KTS AT 3 K FEET AS DEPICTED ON KDLH VAD WIND
PROFILE. THIS JET WAS PUSHING WARM AND MOIST AIR INTO THE
REGION...AND HELPING FUEL THUNDERSTORMS. THE STORMS HAVE DECREASED
IN INTENSITY AS THEY PUSH FARTHER AHEAD OF THE COLD FRONT AND INTO
MORE STABLE AIR. WITH MORE MOISTURE AND HEAT TRANSPORT AHEAD OF
THE FRONT TODAY...EXPECT MORE STORMS TO DEVELOP ALONG AND AHEAD OF
IT...BUT WITH THE LINGER CLOUD COVER FROM THE OVERNIGHT
MCS...STORMS MAY TAKE A WHILE TO DEVELOP. BY NOON THE FRONT SHOULD
BE FROM ABOUT ELY TO BRAINERD...EXPECT THE BULK OF ANY STORMS EAST
OF THE FRONT...WHERE A COMBINATION OF FRONTAL FORCING AND AN UPPER
LEVEL WAVE WILL HELP FORM MORE STORMS. WITH THE FRONT PASSING INTO
NORTHWESTERN WISCONSIN AT THE PEAK OF DAYTIME HEATING AND
INCREASING AFTERNOON INSTABILITY WILL MEAN SOME STRONG STORMS.
WITH WIND SHEAR LACKING ...NORTHWESTERN WI IS IN MARGINAL SEVERE
CATEGORY. THERE IS A THREAT OF HAIL AS UVM IS AIDED THE IN HIGH
CAPE ATMOSPHERE OF OVER 3000 J/KG BY ANOTHER STRONG UPPER WAVE.THE
FRONT WILL EXIT NORTHWEST WISCONSIN LATE TONIGHT. HIGH PRESSURE
WILL BUILD INTO THE NORTHLAND MONDAY. THE COLDER AIR BROUGHT WITH
THE FRONT WILL MAKE FOR A COOLER AND DRIER DAY. COLD AIR BROUGHT T
IN BEHIND THE FRONT WILL BRING 8H TEMPS DOWN TO 6 ABOVE IN
NORTHERN MN. THIS IS MUCH COOLER COMPARED TO THE THE 20C MEASURED
DURING THE 00Z RADIOSONDE DATA AT INL.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 337 AM CDT SUN AUG 16 2015
BEGINNING OF THE EXTENDED PERIOD WILL BE DRY AND DEFINED BY AN AREA
OF HIGH PRESSURE OVER NRN MN AND WRN LAKE SUPERIOR. HOWEVER...THIS
REGIME WILL BE SHORT-LIVED AND REPLACE BY AN ACTIVE/WET PERIOD LATE
TUESDAY THROUGH LATE WED NIGHT/EARLY THURSDAY. AN UPPER LEVEL S/W
WILL DIG EWD THROUGH THE NRN PLAINS AND UPPER MIDWEST DURING THIS
TIME AND LINK UP WITH A DEEPENING SFC LOW OVER THE CENTRAL PLAINS.
AS THIS SFC LOW DEVELOPS A SURGE OF MOIST AIR WILL BE ADVECTED NWD
AHEAD OF THE SYSTEM AND ALLOW CONDITIONS TO BECOME CONDUCIVE FOR
WIDESPREAD RAIN SHOWERS AND SCATTERED THUNDERSTORMS. THE MAIN
CONCERN WITH THIS BROAD SYSTEM WILL BE THE POTENTIAL FOR HEAVY
RAINFALL. THE AIR MASS WILL BE MUCH COOLER AND MORE STABLE...BUT
MUCH MORE RICH WITH MOISTURE. PWATS OVER AN INCH ARE LIKELY. THERE
IS SOME DIFFERENCES AMONG MODELS WITH THE TRACK OF THE SFC LOW WITH
THE GFS BEING THE MOST NWD...TAKING THE LOW INTO NRN WI...AND THE
MOST AGGRESSIVE WITH THE QPF OVER THE NORTHLAND. THE NAM OUTPUT HAS
THE MOST SLY TRACK OF THE LOW THROUGH THE QUAD CITIES AND INTO LAKE
MICHIGAN. THE ECMWF AND GEM SOLUTIONS ARE IN THE MIDDLE. THE
RESULTING RAINFALL AMTS WILL BE HIGHLY DEPENDENT ON THE TRACK OF THE
LOW...SO WILL KEEP MONITORING THE TRENDS OF MODEL OUTPUT THROUGH THE
NEXT 36 HOURS. WIDESPREAD RAIN AMTS AROUND 1 INCH ARE POSSIBLE WITH
LOCALLY HIGHER TOTALS NOT OUT OF THE QUESTION. AT THIS TIME IN
APPEARS THE HIGHEST AMTS COULD END UP ACROSS NRN WI.
AS THE SYSTEM WRAPS UP ON THURSDAY ACROSS THE NRN GREAT LAKES A PUSH
OF COOL AIR ON THE BACK SIDE OF THE SYSTEM COULD STEEPEN LAPSE RATES
ENOUGH TO TRIGGER POST-FRONTAL SHOWERS AND STORMS OVER THE
NORTHLAND. HOWEVER...THE OVERALL TREND LATE THURSDAY WILL BE DRYING
AS HIGH PRESSURE BUILDS IN FROM THE WEST. WEAK RIDGING ALOFT COMBINE
WITH A SFC RIDGE AXIS SLOWLY MOVING ACROSS THE UPPER MIDWEST WILL
KEEP WEATHER CONDITIONS QUIET GOING INTO THE WEEKEND. TEMPERATURES
WILL WARM LATE IN THE PERIOD WITH INCREASING HUMIDITY AS WELL. THESE
CONDITIONS WILL DESTABILIZE THE ATMOSPHERE AND ALLOW FOR A SLIGHT
CHANCE OF SHOWERS AND STORMS...BUT THE GENERALLY OUTLOOK IS DRY LATE
IN THE EXTENDED PERIOD.
TUESDAY AND WEDNESDAY STILL APPEAR TO BE THE COOLEST DAYS OF THE
WEEK WITH A MODEST E/NE WIND OFF LAKE SUPERIOR AND CAA ON-GOING
BEHIND THE FRONT. HIGHS TUE AND WED WILL ONLY REACH INTO THE 60S AND
LOWER 70S WITH NIGHT TIME LOWS IN THE 40S AND 50S. TEMPERATURES WILL
GRADUALLY WARM INTO THE MID TO UPPER 70S THROUGH THE REST OF THE
WEEK WITH OVERNIGHT LOWS IN THE 50S AND LOWER 60S.&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1227 AM CDT SUN AUG 16 2015
A COLD FRONT PUSHING INTO WESTERN MINNESOTA WILL CONTINUE TO BE
THE FOCUS FOR SHOWERS AND THUNDERSTORMS AS THE NIGHT WEARS ON.
SOME OF THE STORMS MAY BE STRONG...ESPECIALLY IN THE KBRD
AREA...WHERE GUSTY WINDS AND SMALL HAIL WILL BE POSSIBLE. THE
SHOWERS AND STORMS WILL BE IN A FAIRLY NARROW CORRIDOR...AND THE
MAIN THREAT IN ANY OF THE TAF SITES THROUGH THE NIGHT AND INTO
MORNING WILL BE A COUPLE HOURS. CONDITIONS WILL THEN IMPROVE
DURING THE DAY SUNDAY...AS THE COLD FRONT STALLS OUT IN NW WI. THE
STALLED OUT FRONT...ALONG WITH A WEAK SYSTEM MOVING ALONG THE
FRONT...WILL SET THE STAGE FOR MORE SHOWER AND THUNDERSTORM
DEVELOPMENT IN THE SOUTH AND EASTERN TAF SITES LATER IN THE DAY
AND INTO THE EVENING. THE BEST CHANCE OF PRECIPITATION DURING THAT
TIME PERIOD WILL BE IN THE KHYR AREA...WHERE SOME STRONG STORMS
WILL BE POSSIBLE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 100 PM CDT SUN AUG 16 2015
BROAD LOW LEVEL MASS CONVERGENCE AXIS ASSOCIATED WITH COLD FRONTAL
ZONE BISECTS THE DULUTH CWA FROM SW TO NE AS OF MIDDAY. WHILE
DEVELOPMENT OF SHOWERS/TSTORMS ALONG AND AHEAD OF THE FRONT IS
LIKELY TO TAKE UNTIL LATE AFTERNOON OR EVENING DUE TO THE STRENGTH
OF THE CAP..LOW-MID LEVEL FGEN ALONG THE NWWD SLOPING FRONTAL
SURFACE CONTINUES TO SUPPORT SHOWERS AND A FEW TSTORMS FROM SE ND
TO NEAR KINL. WE HAVE ADJUSTED THE PRECIP FORECAST IN THE TAFS TO
REFLECT AT LEAST A CHANCE OF VICINITY SHOWERS FOR THE WESTERN TAF
LOCATIONS..AND TRIED TO FINE TUNE TIMING A BIT FOR KDLH/KHYR BUT
THERE REMAINS QUITE A BIT OF UNCERTAINTY AS TO HOW LONG RAIN WILL
PERSIST OVERNIGHT ACROSS NW WISCONSIN. LOW LEVEL RIDGING SHOULD
BUILDING INTO THE AREA FROM NW TO SE AFTER 06Z..GRADUALLY BRINGING
AN END TO PRECIP CHANCES.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 83 59 73 53 / 10 10 10 10
INL 76 49 68 43 / 10 0 10 0
BRD 81 58 73 52 / 20 10 10 10
HYR 83 60 73 51 / 20 60 20 10
ASX 86 60 72 53 / 10 30 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...NONE.
&&
$$
UPDATE...MILLER
SHORT TERM...CLC
LONG TERM...BJT
AVIATION...MILLER
AREA FORECAST DISCUSSION...CORRECTED
NWS DULUTH MN
931 AM CDT SUN AUG 16 2015
.UPDATE...
ISSUED AT 931 AM CDT SUN AUG 16 2015
A BRIEF BREAK IN THE CLOUD COVER THIS MORNING BEFORE MORE CLOUDS
WILL ROLL BACK IN. THE COLD FRONT EXTENDS FROM NEAR CKC TO HZX AT
14Z. SOUTHERLY FLOW AHEAD OF THE FRONT AND A WEST WIND BEHIND THE
FRONT. PLENTY OF INSTABILITY AROUND...BUT MUCIN IS KEEPING ANY
STORMS FROM FIRING. DID INTRODUCE SOME POPS FOR LATE THIS MORNING
IN NW WI AS RAIN IS ATTEMPTING TO GET GOING. ADDED SOME POPS FOR
THE FAR WESTERN EDGE OF THE AREA WHERE THERE IS NO MUCIN...BUT
NOT MUCH CAPE ATTM EITHER. HIRES MODELS INCLUDING THE HRRR AND NMM
INDICATING SOME DEVELOPMENT POSSIBLE IN THIS AREA.
UPDATE ISSUED AT 738 AM CDT SUN AUG 16 2015
SHOWERS HAVE DISSIPATED. UPDATED TO TAKE OUT MENTION OF
THUNDERSTORMS UNTIL THIS AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 337 AM CDT SUN AUG 16 2015
THIS SHORT TERM PERIOD WILL FOCUS ON A COLD FRONT CURRENTLY OVER
NORTHWESTERN MN. A STRONG LOW LEVEL JET AHEAD OF THE COLD FRONT
WAS MEASURED AT 45 KTS AT 3 K FEET AS DEPICTED ON KDLH VAD WIND
PROFILE. THIS JET WAS PUSHING WARM AND MOIST AIR INTO THE
REGION...AND HELPING FUEL THUNDERSTORMS. THE STORMS HAVE DECREASED
IN INTENSITY AS THEY PUSH FARTHER AHEAD OF THE COLD FRONT AND INTO
MORE STABLE AIR. WITH MORE MOISTURE AND HEAT TRANSPORT AHEAD OF
THE FRONT TODAY...EXPECT MORE STORMS TO DEVELOP ALONG AND AHEAD OF
IT...BUT WITH THE LINGER CLOUD COVER FROM THE OVERNIGHT
MCS...STORMS MAY TAKE A WHILE TO DEVELOP. BY NOON THE FRONT SHOULD
BE FROM ABOUT ELY TO BRAINERD...EXPECT THE BULK OF ANY STORMS EAST
OF THE FRONT...WHERE A COMBINATION OF FRONTAL FORCING AND AN UPPER
LEVEL WAVE WILL HELP FORM MORE STORMS. WITH THE FRONT PASSING INTO
NORTHWESTERN WISCONSIN AT THE PEAK OF DAYTIME HEATING AND
INCREASING AFTERNOON INSTABILITY WILL MEAN SOME STRONG STORMS.
WITH WIND SHEAR LACKING ...NORTHWESTERN WI IS IN MARGINAL SEVERE
CATEGORY. THERE IS A THREAT OF HAIL AS UVM IS AIDED THE IN HIGH
CAPE ATMOSPHERE OF OVER 3000 J/KG BY ANOTHER STRONG UPPER WAVE.THE
FRONT WILL EXIT NORTHWEST WISCONSIN LATE TONIGHT. HIGH PRESSURE
WILL BUILD INTO THE NORTHLAND MONDAY. THE COLDER AIR BROUGHT WITH
THE FRONT WILL MAKE FOR A COOLER AND DRIER DAY. COLD AIR BROUGHT T
IN BEHIND THE FRONT WILL BRING 8H TEMPS DOWN TO 6 ABOVE IN
NORTHERN MN. THIS IS MUCH COOLER COMPARED TO THE THE 20C MEASURED
DURING THE 00Z RADIOSONDE DATA AT INL.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 337 AM CDT SUN AUG 16 2015
BEGINNING OF THE EXTENDED PERIOD WILL BE DRY AND DEFINED BY AN AREA
OF HIGH PRESSURE OVER NRN MN AND WRN LAKE SUPERIOR. HOWEVER...THIS
REGIME WILL BE SHORT-LIVED AND REPLACE BY AN ACTIVE/WET PERIOD LATE
TUESDAY THROUGH LATE WED NIGHT/EARLY THURSDAY. AN UPPER LEVEL S/W
WILL DIG EWD THROUGH THE NRN PLAINS AND UPPER MIDWEST DURING THIS
TIME AND LINK UP WITH A DEEPENING SFC LOW OVER THE CENTRAL PLAINS.
AS THIS SFC LOW DEVELOPS A SURGE OF MOIST AIR WILL BE ADVECTED NWD
AHEAD OF THE SYSTEM AND ALLOW CONDITIONS TO BECOME CONDUCIVE FOR
WIDESPREAD RAIN SHOWERS AND SCATTERED THUNDERSTORMS. THE MAIN
CONCERN WITH THIS BROAD SYSTEM WILL BE THE POTENTIAL FOR HEAVY
RAINFALL. THE AIR MASS WILL BE MUCH COOLER AND MORE STABLE...BUT
MUCH MORE RICH WITH MOISTURE. PWATS OVER AN INCH ARE LIKELY. THERE
IS SOME DIFFERENCES AMONG MODELS WITH THE TRACK OF THE SFC LOW WITH
THE GFS BEING THE MOST NWD...TAKING THE LOW INTO NRN WI...AND THE
MOST AGGRESSIVE WITH THE QPF OVER THE NORTHLAND. THE NAM OUTPUT HAS
THE MOST SLY TRACK OF THE LOW THROUGH THE QUAD CITIES AND INTO LAKE
MICHIGAN. THE ECMWF AND GEM SOLUTIONS ARE IN THE MIDDLE. THE
RESULTING RAINFALL AMTS WILL BE HIGHLY DEPENDENT ON THE TRACK OF THE
LOW...SO WILL KEEP MONITORING THE TRENDS OF MODEL OUTPUT THROUGH THE
NEXT 36 HOURS. WIDESPREAD RAIN AMTS AROUND 1 INCH ARE POSSIBLE WITH
LOCALLY HIGHER TOTALS NOT OUT OF THE QUESTION. AT THIS TIME IN
APPEARS THE HIGHEST AMTS COULD END UP ACROSS NRN WI.
AS THE SYSTEM WRAPS UP ON THURSDAY ACROSS THE NRN GREAT LAKES A PUSH
OF COOL AIR ON THE BACK SIDE OF THE SYSTEM COULD STEEPEN LAPSE RATES
ENOUGH TO TRIGGER POST-FRONTAL SHOWERS AND STORMS OVER THE
NORTHLAND. HOWEVER...THE OVERALL TREND LATE THURSDAY WILL BE DRYING
AS HIGH PRESSURE BUILDS IN FROM THE WEST. WEAK RIDGING ALOFT COMBINE
WITH A SFC RIDGE AXIS SLOWLY MOVING ACROSS THE UPPER MIDWEST WILL
KEEP WEATHER CONDITIONS QUIET GOING INTO THE WEEKEND. TEMPERATURES
WILL WARM LATE IN THE PERIOD WITH INCREASING HUMIDITY AS WELL. THESE
CONDITIONS WILL DESTABILIZE THE ATMOSPHERE AND ALLOW FOR A SLIGHT
CHANCE OF SHOWERS AND STORMS...BUT THE GENERALLY OUTLOOK IS DRY LATE
IN THE EXTENDED PERIOD.
TUESDAY AND WEDNESDAY STILL APPEAR TO BE THE COOLEST DAYS OF THE
WEEK WITH A MODEST E/NE WIND OFF LAKE SUPERIOR AND CAA ON-GOING
BEHIND THE FRONT. HIGHS TUE AND WED WILL ONLY REACH INTO THE 60S AND
LOWER 70S WITH NIGHT TIME LOWS IN THE 40S AND 50S. TEMPERATURES WILL
GRADUALLY WARM INTO THE MID TO UPPER 70S THROUGH THE REST OF THE
WEEK WITH OVERNIGHT LOWS IN THE 50S AND LOWER 60S.&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1227 AM CDT SUN AUG 16 2015
A COLD FRONT PUSHING INTO WESTERN MINNESOTA WILL CONTINUE TO BE
THE FOCUS FOR SHOWERS AND THUNDERSTORMS AS THE NIGHT WEARS ON.
SOME OF THE STORMS MAY BE STRONG...ESPECIALLY IN THE KBRD
AREA...WHERE GUSTY WINDS AND SMALL HAIL WILL BE POSSIBLE. THE
SHOWERS AND STORMS WILL BE IN A FAIRLY NARROW CORRIDOR...AND THE
MAIN THREAT IN ANY OF THE TAF SITES THROUGH THE NIGHT AND INTO
MORNING WILL BE A COUPLE HOURS. CONDITIONS WILL THEN IMPROVE
DURING THE DAY SUNDAY...AS THE COLD FRONT STALLS OUT IN NW WI. THE
STALLED OUT FRONT...ALONG WITH A WEAK SYSTEM MOVING ALONG THE
FRONT...WILL SET THE STAGE FOR MORE SHOWER AND THUNDERSTORM
DEVELOPMENT IN THE SOUTH AND EASTERN TAF SITES LATER IN THE DAY
AND INTO THE EVENING. THE BEST CHANCE OF PRECIPITATION DURING THAT
TIME PERIOD WILL BE IN THE KHYR AREA...WHERE SOME STRONG STORMS
WILL BE POSSIBLE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1227 AM CDT SUN AUG 16 2015
A COLD FRONT PUSHING INTO WESTERN MINNESOTA WILL CONTINUE TO BE
THE FOCUS FOR SHOWERS AND THUNDERSTORMS AS THE NIGHT WEARS ON.
SOME OF THE STORMS MAY BE STRONG...ESPECIALLY IN THE KBRD
AREA...WHERE GUSTY WINDS AND SMALL HAIL WILL BE POSSIBLE. THE
SHOWERS AND STORMS WILL BE IN A FAIRLY NARROW CORRIDOR...AND THE
MAIN THREAT IN ANY OF THE TAF SITES THROUGH THE NIGHT AND INTO
MORNING WILL BE A COUPLE HOURS. CONDITIONS WILL THEN IMPROVE
DURING THE DAY SUNDAY...AS THE COLD FRONT STALLS OUT IN NW WI. THE
STALLED OUT FRONT...ALONG WITH A WEAK SYSTEM MOVING ALONG THE
FRONT...WILL SET THE STAGE FOR MORE SHOWER AND THUNDERSTORM
DEVELOPMENT IN THE SOUTH AND EASTERN TAF SITES LATER IN THE DAY
AND INTO THE EVENING. THE BEST CHANCE OF PRECIPITATION DURING THAT
TIME PERIOD WILL BE IN THE KHYR AREA...WHERE SOME STRONG STORMS
WILL BE POSSIBLE.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 83 59 73 53 / 10 10 10 10
INL 76 49 68 43 / 10 0 10 0
BRD 81 58 73 52 / 10 10 10 10
HYR 83 60 73 51 / 40 60 20 10
ASX 84 60 72 53 / 30 30 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...NONE.
&&
$$
UPDATE...GSF
SHORT TERM...CLC
LONG TERM...BJT
AVIATION...TENTINGER
AREA FORECAST DISCUSSION
NWS DULUTH MN
1232 AM CDT SUN AUG 16 2015
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 336 PM CDT SAT AUG 15 2015
HIGH PRESSURE WAS EXITING THE AREA WHILE A SFC LOW WAS MOVING
THROUGH SOUTH CENTRAL CANADA. THIS RESULTED IN A SOUTHERLY FLOW OF
HOT AND HUMID AIR. TEMPERATURES HAD RISEN INTO THE UPPER 80S AND
LOWER 90S THIS AFTERNOON. HEAT INDICES WERE MAINLY IN THE UPPER 80S
AND LOWER 90S AS WELL...BUT TWM REACHED 100 AT 234 PM. CIRRUS WAS
FLOWING OVER THE TOP OF MOST OF THE FORECAST AREA WITH SOME CU IN NW
WI.
THE LINE OF THUNDERSTORMS IN EASTERN ND HAS SHOWN GLIMPSES THAT IT
IS FALLING APART. JUICY ATMOSPHERE OVER THE REGION TONIGHT...BUT THE
INSTABILITY WANES AS THE EVENING PROGRESSES...PLUS THERE IS NO UPPER
FORCING AS THE FRONT REACHES NW MN BY 06Z. DELAYED THE ONSET OF
THUNDERSTORMS TO CLOSER TO 06Z. LATEST HRRR RUNS HAVE NO RAIN IN THE
AREA THROUGH 06Z. BY 12Z...MODELS AGREE ON THE FRONT REACHING NE MN.
HOWEVER...MOISTURE IS DIMINISHING FOR ANY STORMS TO FIRE ON. HAVE
TRIED TO BLEND THE HIRES WITH THE DETERMINISTIC MODELS AND
SURROUNDING OFFICES FOR POPS/QPF/WEATHER.
ON SUNDAY...THE FRONT CONTINUES EWD INTO NW WI. HOWEVER...MOISTURE
IS STILL LIMITED. GREATEST MOISTURE SOURCE WILL BE FOUND ALONG THE
SOUTHERN EDGE OF THE REGION WHERE POPS ARE HIGHEST. MODELS DIFFER ON
THE TIMING AND QPF AND USED A BLEND WITH NEIGHBORING OFFICES.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 336 PM CDT SAT AUG 15 2015
SUNDAY NIGHT THE FRONT CONTINUES TO SLOWLY SAG SOUTHEAST ACROSS THE
FORECAST AREA...WITH SOME POTENTIAL FOR SHOWERS AND THUNDERSTORMS
ACROSS MAINLY THE SOUTHEASTERN CWA THAT CONTINUES INTO MONDAY DUE TO
THE SLOW FRONT MOVEMENT. WE ENTER A QUIET PERIOD FOR MONDAY NIGHT
AND EARLY TUESDAY WITH A SURFACE RIDGE IN THE VICINITY AND
SEASONABLE TEMPERATURES.
THE NEXT MAJOR WEATHER MAKER WILL AFFECT THE FORECAST AREA MUCH OF
THE UPCOMING WORK WEEK...WITH AN UPPER LEVEL TROUGH AXIS/LOW MOVING
FROM THE ROCKIES ON MONDAY NIGHT...MOVING ACROSS MINNESOTA
WEDNESDAY...AND OFF TO THE EAST THURSDAY. THERE IS STILL QUITE A
BIT OF UNCERTAINTY IN THE TRACK AND TIMING OF THIS STORM...WITH THE
ECMWF FARTHER SOUTH AND MORE PROGRESSIVE THAN THE GFS. IT STILL
LOOKS LIKE THIS STORM SHOULD BRING A PERIOD OF WET WEATHER AND
COOLER TEMPERATURES TO THE NORTHLAND. FOR NOW HAVE KEPT TO THE
CONSENSUS WITH HIGHS TUESDAY-THURSDAY IN THE MID 60S TO MID 70S WITH
CHANCE TO LIKELY POPS BEGINNING TUESDAY NIGHT AND CONTINUING THROUGH
THURSDAY. FRIDAY AND SATURDAY REMAIN ACTIVE WITH CONTINUING CHANCES
FOR SHOWERS AND THUNDERSTORMS AND HIGHS IN THE 70S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1227 AM CDT SUN AUG 16 2015
A COLD FRONT PUSHING INTO WESTERN MINNESOTA WILL CONTINUE TO BE
THE FOCUS FOR SHOWERS AND THUNDERSTORMS AS THE NIGHT WEARS ON.
SOME OF THE STORMS MAY BE STRONG...ESPECIALLY IN THE KBRD
AREA...WHERE GUSTY WINDS AND SMALL HAIL WILL BE POSSIBLE. THE
SHOWERS AND STORMS WILL BE IN A FAIRLY NARROW CORRIDOR...AND THE
MAIN THREAT IN ANY OF THE TAF SITES THROUGH THE NIGHT AND INTO
MORNING WILL BE A COUPLE HOURS. CONDITIONS WILL THEN IMPROVE
DURING THE DAY SUNDAY...AS THE COLD FRONT STALLS OUT IN NW WI. THE
STALLED OUT FRONT...ALONG WITH A WEAK SYSTEM MOVING ALONG THE
FRONT...WILL SET THE STAGE FOR MORE SHOWER AND THUNDERSTORM
DEVELOPMENT IN THE SOUTH AND EASTERN TAF SITES LATER IN THE DAY
AND INTO THE EVENING. THE BEST CHANCE OF PRECIPITATION DURING THAT
TIME PERIOD WILL BE IN THE KHYR AREA...WHERE SOME STRONG STORMS
WILL BE POSSIBLE.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 59 74 53 65 / 10 10 10 30
INL 49 69 45 71 / 0 10 0 10
BRD 58 75 54 70 / 10 10 10 40
HYR 60 74 51 71 / 60 20 10 40
ASX 60 73 52 69 / 30 10 10 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...NONE.
&&
$$
SHORT TERM...GSF
LONG TERM...LE
AVIATION...DAP/WEL
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1134 PM CDT SAT AUG 15 2015
.UPDATE:
ISSUED AT 937 PM CDT SAT AUG 15 2015
SCATTERED THUNDERSTORMS OVER ILLINOIS HAVE DISSIPATED OVER THE
PAST COUPLE OF HOURS WITH THE LOSS OF DAYTIME HEATING. LATEST RUNS
OF THE RAP AND HRRR DO NOT SUGGEST ANY REDEVELOPMENT OF THUNDERSTORMS
OVER THE AREA OVERNIGHT. DEBRIS CLOUDS ARE CURRENTLY DISSIPATING
SO WILL GO WITH MAINLY CLEAR SKIES OVERNIGHT. GOING LOWS STILL
LOOK GOOD.
BRITT
&&
.SHORT TERM: (THROUGH LATE TONIGHT)
ISSUED AT 355 PM CDT SAT AUG 15 2015
KEEPING AN EYE ON STORM OVER S IL BETWEEN K1H2 AND KRSV AS IT DRIFTS
SW, BUT BELIEVE IT WILL DISSIPATE OVER THE NEXT HOUR OR SO...BEFORE
IT REACHES OUR FAR E COUNTIES.
OTHERWISE...SURFACE RIDGE WILL CONTINUE TO EXERT ITS INFLUENCE OVER
THE REGION`S WEATHER TONIGHT, WITH LATEST GUIDANCE SUGGESTING ONLY A
VERY MODEST DECREASE IN ITS STRENGTH. WITH LITTLE CHANGE IN AMS,
HAVE GENERALLY GONE WITH PERSISTENCE FOR MOST ELEMENTS WITH A VERY
SUBTLE UPTICK IN SOUTH/SOUTHEAST WINDS. THIS INCREASE IN MIXING MAY
TEND TO INHIBIT STEAM/RIVER FOG JUST A BIT, SO HAVE KEPT MENTION OUT
OF FORECAST FOR NOW.
TRUETT
.LONG TERM: (SUNDAY THROUGH NEXT SATURDAY)
ISSUED AT 355 PM CDT SAT AUG 15 2015
ADDED SLIGHT CHANCE POPS TO PARTS OF SOUTHEAST MO ON SUNDAY
AFTERNOON AS AN UPPER LEVEL DISTURBANCE CURRENTLY OVER IN WESTERN OH
AND SOUTHEAST INDIANA SLIDES SOUTHWESTWARD INTO THIS AREA 24HRS FROM
NOW.
OTHERWISE...FORECAST RELATIVELY UNCHANGED FROM PREVIOUS ISSUANCE
WITH THE OVERALL UPPER LEVEL RIDGE AXIS SETUP COLLAPSING TO OUR
WEST...THE UPPER LEVEL DISTURBANCE FROM SUNDAY LINGERS INTO MONDAY
TO BE THE MAIN WX-MAKER...AND THEN A SURFACE FRONT APPROACHES LATE
MONDAY AND LINGERS INTO TUESDAY WITH THE RESUMPTION OF THE UPPER
LEVEL WESTERLIES. THE RAIN CHANCES LOOK TO BE FURTHER ENHANCED WITH
A DEEP UPPER LEVEL TROF MOVING THRU ON WEDNESDAY. WHILE THE DETAILS
REMAIN MURKY...THERE IS POTENTIAL THAT IF THE TIMING AND TRACK ARE
RIGHT...THIS WILL HAVE THE DYNAMICS COMBINED WITH THE TYPICAL AUGUST
THERMODYNAMICS FOR ORGANIZED SEVERE STORM POTENTIAL.
LOW CHANCES FOR RAIN REMAIN HEADING INTO LATE NEXT WEEK BUT COULD
END UP BEING LOWER/MORE DRY THAN CURRENTLY FORECAST IF THE MID-WEEK
SYSTEM SCOURS THE MOISTURE OUT ENOUGH.
OTHERWISE...SEASONABLE AUGUST TEMPS TO CONTINUE THRU MID-WEEK WITH A
BRIEF REPRIEVE WITH THE MID-WEEK SYSTEM AND IMMEDIATELY AFTERWARD...
WITH A RECOVERY BACK TO NORMAL BY NEXT WEEKEND.
TES
&&
.AVIATION: (FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1132 PM CDT SAT AUG 15 2015
SOME FOG STILL APPEARS LIKELY LATER ON TONIGHT FOR KSUS AND KCPS
WITH SOME HAZE POSSIBLE AT KCOU AND KSTL. WINDS WILL BECOME
SOUTHEAST BY SUNDAY MORNING ALONG WITH FEW-SCT DIURNAL CU WITH
BASES AOA 4000 FEET AGL. ISOLATED STORMS POSSIBLE ACROSS EASTERN
OZARKS SUNDAY AFTERNOON/EVENING EXPECTED TO STAY SOUTH AND EAST OF
TERMINALS.
SPECIFICS FOR KSTL:
COULD BE SOME HAZE EARLY SUNDAY MORNING. OTHERWISE...EXPECT WINDS
TO BECOME SSE BY LATE SUNDAY MORNING ALONG WITH CU DEVELOPING. ANY
STORMS WHICH FORM SUNDAY AFTERNOON/EVENING ARE EXPECTED TO STAY
SOUTH AND EAST OF TERMINAL.
GOSSELIN
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
924 PM MDT MON AUG 17 2015
.UPDATE...
PRECIPITATION WAS MOVING STEADILY E THROUGH SE MT AND E SHERIDAN
COUNTY AT 03Z. MODELS WERE SLOWER IN MOVING THE PRECIPITATION E
THAN WHAT WAS DEPICTED ON RADAR. ADJUSTED POPS THROUGH THE NIGHT
TO REFLECT A COMBINATION OF RADAR AND MODEL TRENDS. STRONG
SHORTWAVE IN THE UPPER TROUGH ON WATER VAPOR WAS ROTATING E THIS
EVENING AND MODELS BROUGHT THE WAVE INTO W SD AND W NE BY 12Z
TUE. EARLIER STORMS PRODUCED COPIOUS AMOUNTS OF SMALL HAIL AND
HEAVY RAINFALL. THE STRONG SHEAR WAS S OF THE REGION AT 03Z...BUT
WITH THE STRONG WAVE IN THE AREA...MODERATE TO HEAVY RAINFALL WAS
STILL POSSIBLE THROUGH THE EVENING OVER SE MT.
GIVEN THAT TEMPERATURES WERE ALREADY IN THE 40S AND 50S THIS
EVENING...HAVE LOWERED MINS TOWARD THE ADJMAVBC. A FAIR AMOUNT OF
CLOUD COVER WILL REMAIN OVER SE MT THROUGH THE NIGHT BASED ON IR
SATELLITE TRENDS. RAP SOUNDINGS SHOWED A SATURATED LAYER AT THE
SURFACE OVER KMLS AND KBIL BY MORNING. GIVEN THE EXPECTED CLOUD
COVER...WILL NOT FORECAST WIDESPREAD FOG...BUT DID ADD PATCHY FOG
TO THE YELLOWSTONE RIVER VALLEY OVERNIGHT.
MORE VORTICITY MOVES S IN THE UPPER FLOW ON THE BACK SIDE OF THE
TROUGH ON TUE...BRINGING ANOTHER ROUND OF SHOWERS AND STORMS TO
THE AREA. A DRYING UPPER RIDGE WILL BUILD IN FOR WED. ARTHUR
&&
.SHORT TERM...VALID FOR TUE AND WED...
UPPER LEVEL LOW IS CURRENTLY OVER NORTHERN PARK COUNTY...MOVING
EAST SOUTHEAST. OUT AHEAD OF THIS SYSTEM STRONG UPPER LEVEL ENERGY
AND LOW LEVEL ISENTROPIC LIFT IS GENERATING SHOWERS AND
THUNDERSTORMS. TRACK OF THE SYSTEM HAS SHIFTED A BIT NORTH OF THE
MORNING MODEL RUNS WHICH HAS PUT THE BEST FORCING NORTH OF A
LIVINGSTON TO BILLINGS TO ASHLAND LINE THIS AFTERNOON. TO THE
NORTH OF THIS LINE MORE SUSTAINED PRECIPITATION IS OCCURRING AND
TO THE SOUTH PRECIPITATION IS MORE CONVECTIVE AND SCATTERED IN
NATURE. A SURFACE WARM FRONT HAS SHIFTED NORTHWARD OUT OF WYOMING
AND IS LYING FROM SHERIDAN COUNTY NORTHEAST INTO POWDER RIVER
COUNTY AND THEN TOWARD THE BAKER VICINITY. ENHANCED VORTICITY AND
SHEAR ALONG THIS BOUNDARY HAS CREATED JUST ENOUGH DYNAMICS TO
SUPPORT AN ISOLATED STRONG TO SEVERE THUNDERSTORM THIS AFTERNOON
AND A SEVERE THUNDERSTORM WATCH HAS BEEN ISSUED FOR THIS VICINITY
UNTIL 10 PM MDT. WATCH EXTENDS FURTHER WEST INTO CARBON COUNTY TO
ACCOUNT FOR POTENTIAL FOR STORMS WITH STRONG WIND GUSTS MOVING
INTO THE BIG HORN BASIN. SEVERE THREAT LOOKS LIKE IT WILL STAY
SOUTH OF THE I-94 CORRIDOR IN ROSEBUD AND CUSTER COUNTIES.
UPPER STORM SYSTEM WILL CROSS OUT OF THE AREA LATE TONIGHT BUT
ENERGY ON THE BACK SIDE OF THE TROF WILL LINGER OVER EASTERN ZONES
INTO TOMORROW MORNING. THUS PRECIPITATION CHANCES WILL TAPER OFF
WEST OF ROSEBUD COUNTY LATE THIS EVENING...WITH CONTINUING CHANCES
EAST INTO THE EARLY MORNING TUESDAY.
AREA REMAINS UNDER THE UPPER TROF ON TUESDAY AND ANOTHER CHUNK OF
ENERGY DROPS DOWN FROM THE NORTH AND CURVES JUST ENOUGH TO BRING
SOME DECENT DYNAMICS TO THE AREA TUESDAY AFTERNOON. THIS WILL
PRODUCE ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS TOMORROW
AFTERNOON AND EVENING. THIS SYSTEM IS QUICK MOVING AND SHOULD SEE
PRECIPITATION CHANCES DROP QUICKLY BY LATE IN THE EVENING.
RIDGE BUILDS INTO THE AREA ON WEDNESDAY FOR SUNNY WARMER AND DRY
CONDITIONS. AFTER SEVERAL DAYS IN THE LOWER 70S...TEMPERATURES
WILL CLIMB TOWARD 80 DEGREES WEDNESDAY AFTERNOON. CHAMBERS
.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...
MODELS REMAIN IN GOOD AGREEMENT THROUGH FRIDAY AFTERNOON WITH
RIDGING REMAINING DOMINANT THROUGH THURSDAY WHILE AN UPPER LOW
BRINGS HEIGHT FALLS AND UNSETTLED WEATHER LATE THIS WEEK.
WITH THE RETURN OF AN UPPER-LEVEL RIDGE CONDITIONS SHOULD BEGIN
WARMING UP WEDNESDAY AFTERNOON THROUGH FRIDAY. COLD FRONT SWINGS
THROUGH THE AREA SOMETIME FRIDAY EVENING INTO SATURDAY MORNING
BRINGING WITH IT A CHANCE FOR SHOWERS AND THUNDERSTORMS. AFTER
THE COLD FRONT...TEMPERATURES WILL RETURN TO BELOW NORMAL AS
NORTHERLY WINDS AND UPPER LEVEL CLOUDS KEEP CONDITIONS COOL. FOR
NOW...APPEARS OUR AREA WILL RETURN TO RIDGING AND AN INCREASE IN
TEMPERATURES AND DECREASE IN RAIN CHANCES. DOBBS
&&
.AVIATION...
RAIN AND A FEW THUNDERSTORMS WILL MOVE THROUGH SE MT...SE AND E
OF KMLS THROUGH THE NIGHT. CONDITIONS WILL BE MVFR TO IFR IN THE
PRECIPITATION. PATCHY FOG IS POSSIBLE ALONG THE YELLOWSTONE RIVER
VALLEY OVERNIGHT WITH LOCAL REDUCTIONS IN VISIBILITY. SHOWERS AND
A FEW THUNDERSTORMS WILL REDEVELOP OVER THE AREA ON TUE WITH MVFR
CONDITIONS. AREAS OF MOUNTAIN OBSCURATION TUE MORNING WILL BECOME
WIDESPREAD TUE AFTERNOON. ARTHUR
&&
.PRELIMINARY POINT TEMP/POPS...
TUE WED THU FRI SAT SUN MON
-----------------------------------------------------------
BIL 047/069 049/078 055/087 058/089 052/068 050/084 056/088
04/T 30/B 01/U 12/T 33/T 21/U 11/U
LVM 043/070 042/079 049/084 051/082 047/072 045/084 050/086
05/T 20/U 01/U 12/T 33/T 11/U 11/U
HDN 047/071 048/079 052/088 057/092 051/070 049/085 054/090
05/T 31/B 01/U 12/T 33/T 21/U 11/U
MLS 047/071 050/076 054/088 058/091 053/069 048/085 055/089
25/T 31/B 01/U 11/B 44/T 21/U 11/U
4BQ 051/068 051/074 053/086 057/091 053/068 049/083 054/089
85/T 41/B 01/U 11/U 22/T 21/U 11/U
BHK 048/069 048/073 050/085 055/090 052/067 048/081 051/088
55/T 31/B 01/U 11/B 33/T 31/U 11/U
SHR 045/067 045/074 049/083 051/088 050/070 046/084 049/089
25/T 51/B 01/U 11/B 22/T 21/U 11/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
911 PM MDT MON AUG 17 2015
.UPDATE...
STRONG TO SEVERE STORMS HAVE DIMINISHED OR MOVED OUT OF THE CWA.
CONSEQUENTLY REMOVED MENTION FROM WX GRID AND DECREASED POPS FOR
THE EVENING...SHORT TERM MODELS NOT AS BULLISH AS THEY WERE A FEW
HOURS AGO WITH HOLDING ONTO PRECIPITATION IN THE EAST AFTER
MIDNIGHT. UPDATED ZFP ALREADY TRANSMITTED.
&&
.PREV DISCUSSION...541 PM MDT MON AUG 17 2015...
.AVIATION...
00Z TAF CYCLE
NORTHWEST FLOW ALOFT WITH DRIER AIR PUSHING INTO WESTERN AND
CENTRAL NM. ISOLD SHOWERS/STORMS GENLY FROM THE RGV WESTWARD WITH
SCATTERED ACTIVITY...AND ISOLD SVR STORMS WITH LARGE
HAIL...CENTRAL MT CHAIN EASTWARD. MVFR/IFR CIGS/VBSYS IN THE
STRONGER ACTIVITY WITH BRIEF TERRAIN OBSCURATIONS. SHORT TERM
MODELS INDICATE CONVECTION TO PERSIST OVER THE ERN PLAINS AFT
06Z. SURFACE BOUNDARY TO DROP INTO THE ERN PLAINS AFT 18/15Z BUT
DRIER AIR ALOFT WILL CONTINUE TO SPREAD OVER THE REGION ON NW FLOW
ALOFT.
&&
.PREV DISCUSSION...341 PM MDT MON AUG 17 2015...
.SYNOPSIS...
SEVERE THUNDERSTORMS WILL REMAIN POSSIBLE THROUGH THE EVENING
ACROSS MUCH OF NORTHEAST NEW MEXICO. LARGE HAIL AND DAMAGING WINDS
WILL BE THE MAIN THREATS. THEREAFTER...A DRYING TREND WILL
COMMENCE. MUCH FEWER STORMS ARE EXPECTED TUESDAY THROUGH THURSDAY.
A BACK DOOR FRONT ON TUESDAY NIGHT WILL RESULT IN FALL LIKE
TEMPERATURES ON WEDNESDAY ACROSS THE EASTERN PLAINS. LATER IN THE
WEEK...A SLOW INCREASE IN THUNDERSTORM ACTIVITY IS POSSIBLE.
&&
.DISCUSSION...
SEVERE WEATHER REMAINS POSSIBLE THROUGH THIS EVENING ACROSS THE
NORTHEAST QUADRANT OF NM. 35 TO 40KTS OF BULK SHEAR AND CAPE UP TO
2500 J/KG PER LAPS ANALYSIS WILL PROVIDE AN ENVIRONMENT VERY
SUITABLE FOR STORMS TO BECOME SEVERE AS THEY MOVE OFF THE HIGHER
TERRAIN INTO THE NE PLAINS. A JET MAX WILL ALSO AID IN TSTM
DEVELOPMENT AND FOCUS ACTIVITY ACROSS THE NE. LARGE HAIL AND
DAMAGING WIND GUSTS WILL BE THE MAIN THREAT WITH THIS ACTIVITY.
THE LATEST HRRR SHOWS MOST OF THIS INITIAL ROUND OF ACTIVITY
EXITING NM BY MID EVENING...BUT ANOTHER ROUND OF STORMS MAY
DEVELOP LATER THANKS TO OUTFLOW BOUNDARIES MOVING IN FROM SE CO.
THE UPPER LEVEL TROUGH WILL CROSS THE CENTRAL ROCKIES TONIGHT AND
THE ASSOCIATED PACIFIC FRONT WILL SLIDE THROUGH CENTRAL AND
WESTERN NM. MUCH DRIER AIR BEHIND THE TROUGH AND BREEZY WINDS WILL
MIX DOWN TO THE SURFACE...RESULTING IN SOME OF THE LOWEST
DEWPOINTS WE HAVE SEEN ACROSS THE NW SINCE THE SPRING.
MEANWHILE...THE BACK DOOR SEGMENT OF THE FRONT WILL SLIDE DOWN THE
PLAINS. A FEW STORMS MAY DEVELOP ALONG THE FRONT AND ALONG THE
EAST SLOPES OF THE SANGRES...BUT THE DEEP LAYER OF DRIER AIR ALOFT
WILL LIMIT COVERAGE SIGNIFICANTLY. THE FRONT SHOULD PUSH THRU THE
GAPS OF THE CENTRAL MTN CHAIN TUESDAY NIGHT...BUT THE MOISTURE IT
BRINGS WITH IT SHOULD QUICKLY MIX OUT ON WEDNESDAY WITHIN THE RGV.
ON WEDNESDAY...SOME OF THE MOISTURE ACROSS THE PLAINS WILL ALSO
MIX OUT. CONTINUE LOW LEVEL SOUTHEASTERLY FLOW...HOWEVER...MAY
YIELD A STRAY SHOWER OR TSTM ALONG THE CENTRAL MTN CHAIN...BUT
CONFIDENCE IS PRETTY LOW. THE BIGGER STORY WILL BE THE MUCH COOLER
TEMPS ACROSS THE EAST IN THE WAKE OF THE BACK DOOR FRONT. MOST
AREAS WILL STRUGGLE TO REACH 80.
ANOTHER WEAK WAVE LOOKS TO CROSS NM ON THURSDAY...BUT CONTINUED
DRY AIR OVER THE STATE WILL CONTINUE TO LIMIT TSTM ACTIVITY. SE
PORTIONS OF THE CWA MAY BE FAVORED FOR AN ISOLATED STORM WHERE
BETTER LOW LEVEL MOISTURE EXISTS.
CONFIDENCE REMAINS LOW IN THE FORECAST FRIDAY AND BEYOND. MODELS
CONTINUE TO SUGGEST SOME MOISTURE WILL SEEP UP INTO NM AND WE WILL
SEE A GRADUAL INCREASE IN TSTM ACTIVITY. OF MORE CERTAINTY LOOKS
TO BE ANOTHER BACK DOOR COLD FRONT SLIDING DOWN THE PLAINS OVER
THE WEEKEND WHICH WILL HELP TO MOISTEN UP LOW LEVELS...BUT THE
PARENT TROUGH MAY BRING DRIER AIR OVER NORTHERN NM ONCE AGAIN.
STAY TUNED.
34
&&
.FIRE WEATHER...
FAIRLY ACTIVE AND VIGOROUS BATCH OF SHOWERS AND STORMS AS OF MID
AFTN STRETCHING FROM THE SANGRE DE CRISTOS AND NE HIGHLANDS AND
PLAINS SOUTH AND SOUTHWESTWARD TO THE CENTRAL HIGHLANDS AND MID TO
LOWER RIO GRANDE VALLEY. A FEW HAVE ALREADY BECOME SEVERE ACROSS
THE NORTHERN PORTION OF THIS AREA. THIS ACTIVITY WILL EXPAND SOME
ACROSS THE EASTERN PLAINS THROUGH THE EVE. MOST OF THE NW THIRD OF
THE STATE WILL BE DRY THROUGH THE EVENING AND THIS DRYING TREND
WILL EXPAND SOUTH AND EAST OVER THE NEXT 24 TO 48 HOURS IN THE
WAKE OF A SIGNIFICANT AND EARLIER THAN USUAL MID TO UPPER LOW
PRESSURE TROUGH. ACCOMPANYING AND IN THE WAKE OF THE TROUGH WILL
BE A STRENGTHENING NORTHWEST FLOW ALOFT OVER CENTRAL AND NORTHERN
NEW MEXICO THAT WILL USHER THE MUCH DRIER AIR MASS FROM NW TO SE.
WEST AND NW NEAR SFC WINDS WILL BE PERKING UP SIGNIFICANTLY ACROSS
MUCH OF NORTHERN NM TUE IN RESPONSE TO THE INCREASED NW FLOW ALOFT.
SOME SPOTTY AND LOCALIZED CRITICAL FIRE WEATHER CONDITIONS WILL BE
POSSIBLE OVER AREAS MAINLY BETWEEN THE NW PLATEAU AND THE HIGH
TERRAIN OF RIO ARRIBA AND LOS ALAMOS COUNTIES. THESE CONDITIONS ARE
NOT EXPECTED TO BE WIDESPREAD AND GIVEN CURRENT FUEL STATUS AND
LOW/MODERATE FIRE DANGER...FIRE WEATHER HIGHLIGHTS WILL NOT BE
ISSUED. STILL MIN RH WILL REALLY CRATER OCCUR ON TUE. SURFACE DEW
POINTS WILL DROP INTO THE 20S AND 30S ACROSS THE NW THIRD TO
NEARLY HALF OF FCST AREA TUE AFTN.
DAYTIME TEMPS WILL LOWER BY 5 TO 15 DEGREES...THE MOST EAST...WED IN
WAKE OF AN ASSOCIATED PACIFIC FRONT AS WELL AS A BACKDOOR SEGMENT OF
THE FRONTAL SYSTEM. THE LATTER WILL REACH NE AREAS ON TUESDAY...WITH
THE MAIN SOUTHWARD SURGE TUE NIGHT INTO WED. THIS SHOULD BRING AT
LEAST A MODERATE EAST GAP WIND INTO PORTIONS OF THE RIO GRANDE
VALLEY AND THUS DEW POINTS WILL RECOVER EAST OF THE CENTRAL
MOUNTAIN CHAIN AND TO A LESSER DEGREE INTO THE RIO GRANDE VALLEY FOR
WED.
THE WED TO THU PERIOD SHOULD FEATURE LITTLE OR NO THUNDER IN THE
FCST AREA. EXPECT WARMING TEMPERATURES AND SLIGHT MOISTURE INCREASE
FOR LATE WEEK AS HIGH PRESSURE BUILDS AND THE AIR MASS GRADUALLY
RECOVERS. EXCELLENT VENTILATION THE NEXT 3 TO 5 DAYS...EXCEPT THE
EAST HALF ON WED MAY ONLY REACH FAIR TO GOOD LVLS.
43
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
541 PM MDT MON AUG 17 2015
.AVIATION...
00Z TAF CYCLE
NORTHWEST FLOW ALOFT WITH DRIER AIR PUSHING INTO WESTERN AND
CENTRAL NM. ISOLD SHOWERS/STORMS GENLY FROM THE RGV WESTWARD WITH
SCATTERED ACTIVITY...AND ISOLD SVR STORMS WITH LARGE
HAIL...CENTRAL MT CHAIN EASTWARD. MVFR/IFR CIGS/VBSYS IN THE
STRONGER ACTIVITY WITH BRIEF TERRAIN OBSCURATIONS. SHORT TERM
MODELS INDICATE CONVECTION TO PERSIST OVER THE ERN PLAINS AFT
06Z. SURFACE BOUNDARY TO DROP INTO THE ERN PLAINS AFT 18/15Z BUT
DRIER AIR ALOFT WILL CONTINUE TO SPREAD OVER THE REGION ON NW FLOW
ALOFT.
&&
.PREV DISCUSSION...341 PM MDT MON AUG 17 2015...
.SYNOPSIS...
SEVERE THUNDERSTORMS WILL REMAIN POSSIBLE THROUGH THE EVENING
ACROSS MUCH OF NORTHEAST NEW MEXICO. LARGE HAIL AND DAMAGING WINDS
WILL BE THE MAIN THREATS. THEREAFTER...A DRYING TREND WILL
COMMENCE. MUCH FEWER STORMS ARE EXPECTED TUESDAY THROUGH THURSDAY.
A BACK DOOR FRONT ON TUESDAY NIGHT WILL RESULT IN FALL LIKE
TEMPERATURES ON WEDNESDAY ACROSS THE EASTERN PLAINS. LATER IN THE
WEEK...A SLOW INCREASE IN THUNDERSTORM ACTIVITY IS POSSIBLE.
&&
.DISCUSSION...
SEVERE WEATHER REMAINS POSSIBLE THROUGH THIS EVENING ACROSS THE
NORTHEAST QUADRANT OF NM. 35 TO 40KTS OF BULK SHEAR AND CAPE UP TO
2500 J/KG PER LAPS ANALYSIS WILL PROVIDE AN ENVIRONMENT VERY
SUITABLE FOR STORMS TO BECOME SEVERE AS THEY MOVE OFF THE HIGHER
TERRAIN INTO THE NE PLAINS. A JET MAX WILL ALSO AID IN TSTM
DEVELOPMENT AND FOCUS ACTIVITY ACROSS THE NE. LARGE HAIL AND
DAMAGING WIND GUSTS WILL BE THE MAIN THREAT WITH THIS ACTIVITY.
THE LATEST HRRR SHOWS MOST OF THIS INITIAL ROUND OF ACTIVITY
EXITING NM BY MID EVENING...BUT ANOTHER ROUND OF STORMS MAY
DEVELOP LATER THANKS TO OUTFLOW BOUNDARIES MOVING IN FROM SE CO.
THE UPPER LEVEL TROUGH WILL CROSS THE CENTRAL ROCKIES TONIGHT AND
THE ASSOCIATED PACIFIC FRONT WILL SLIDE THROUGH CENTRAL AND
WESTERN NM. MUCH DRIER AIR BEHIND THE TROUGH AND BREEZY WINDS WILL
MIX DOWN TO THE SURFACE...RESULTING IN SOME OF THE LOWEST
DEWPOINTS WE HAVE SEEN ACROSS THE NW SINCE THE SPRING.
MEANWHILE...THE BACK DOOR SEGMENT OF THE FRONT WILL SLIDE DOWN THE
PLAINS. A FEW STORMS MAY DEVELOP ALONG THE FRONT AND ALONG THE
EAST SLOPES OF THE SANGRES...BUT THE DEEP LAYER OF DRIER AIR ALOFT
WILL LIMIT COVERAGE SIGNIFICANTLY. THE FRONT SHOULD PUSH THRU THE
GAPS OF THE CENTRAL MTN CHAIN TUESDAY NIGHT...BUT THE MOISTURE IT
BRINGS WITH IT SHOULD QUICKLY MIX OUT ON WEDNESDAY WITHIN THE RGV.
ON WEDNESDAY...SOME OF THE MOISTURE ACROSS THE PLAINS WILL ALSO
MIX OUT. CONTINUE LOW LEVEL SOUTHEASTERLY FLOW...HOWEVER...MAY
YIELD A STRAY SHOWER OR TSTM ALONG THE CENTRAL MTN CHAIN...BUT
CONFIDENCE IS PRETTY LOW. THE BIGGER STORY WILL BE THE MUCH COOLER
TEMPS ACROSS THE EAST IN THE WAKE OF THE BACK DOOR FRONT. MOST
AREAS WILL STRUGGLE TO REACH 80.
ANOTHER WEAK WAVE LOOKS TO CROSS NM ON THURSDAY...BUT CONTINUED
DRY AIR OVER THE STATE WILL CONTINUE TO LIMIT TSTM ACTIVITY. SE
PORTIONS OF THE CWA MAY BE FAVORED FOR AN ISOLATED STORM WHERE
BETTER LOW LEVEL MOISTURE EXISTS.
CONFIDENCE REMAINS LOW IN THE FORECAST FRIDAY AND BEYOND. MODELS
CONTINUE TO SUGGEST SOME MOISTURE WILL SEEP UP INTO NM AND WE WILL
SEE A GRADUAL INCREASE IN TSTM ACTIVITY. OF MORE CERTAINTY LOOKS
TO BE ANOTHER BACK DOOR COLD FRONT SLIDING DOWN THE PLAINS OVER
THE WEEKEND WHICH WILL HELP TO MOISTEN UP LOW LEVELS...BUT THE
PARENT TROUGH MAY BRING DRIER AIR OVER NORTHERN NM ONCE AGAIN.
STAY TUNED.
34
&&
.FIRE WEATHER...
FAIRLY ACTIVE AND VIGOROUS BATCH OF SHOWERS AND STORMS AS OF MID
AFTN STRETCHING FROM THE SANGRE DE CRISTOS AND NE HIGHLANDS AND
PLAINS SOUTH AND SOUTHWESTWARD TO THE CENTRAL HIGHLANDS AND MID TO
LOWER RIO GRANDE VALLEY. A FEW HAVE ALREADY BECOME SEVERE ACROSS
THE NORTHERN PORTION OF THIS AREA. THIS ACTIVITY WILL EXPAND SOME
ACROSS THE EASTERN PLAINS THROUGH THE EVE. MOST OF THE NW THIRD OF
THE STATE WILL BE DRY THROUGH THE EVENING AND THIS DRYING TREND
WILL EXPAND SOUTH AND EAST OVER THE NEXT 24 TO 48 HOURS IN THE
WAKE OF A SIGNIFICANT AND EARLIER THAN USUAL MID TO UPPER LOW
PRESSURE TROUGH. ACCOMPANYING AND IN THE WAKE OF THE TROUGH WILL
BE A STRENGTHENING NORTHWEST FLOW ALOFT OVER CENTRAL AND NORTHERN
NEW MEXICO THAT WILL USHER THE MUCH DRIER AIR MASS FROM NW TO SE.
WEST AND NW NEAR SFC WINDS WILL BE PERKING UP SIGNIFICANTLY ACROSS
MUCH OF NORTHERN NM TUE IN RESPONSE TO THE INCREASED NW FLOW ALOFT.
SOME SPOTTY AND LOCALIZED CRITICAL FIRE WEATHER CONDITIONS WILL BE
POSSIBLE OVER AREAS MAINLY BETWEEN THE NW PLATEAU AND THE HIGH
TERRAIN OF RIO ARRIBA AND LOS ALAMOS COUNTIES. THESE CONDITIONS ARE
NOT EXPECTED TO BE WIDESPREAD AND GIVEN CURRENT FUEL STATUS AND
LOW/MODERATE FIRE DANGER...FIRE WEATHER HIGHLIGHTS WILL NOT BE
ISSUED. STILL MIN RH WILL REALLY CRATER OCCUR ON TUE. SURFACE DEW
POINTS WILL DROP INTO THE 20S AND 30S ACROSS THE NW THIRD TO
NEARLY HALF OF FCST AREA TUE AFTN.
DAYTIME TEMPS WILL LOWER BY 5 TO 15 DEGREES...THE MOST EAST...WED IN
WAKE OF AN ASSOCIATED PACIFIC FRONT AS WELL AS A BACKDOOR SEGMENT OF
THE FRONTAL SYSTEM. THE LATTER WILL REACH NE AREAS ON TUESDAY...WITH
THE MAIN SOUTHWARD SURGE TUE NIGHT INTO WED. THIS SHOULD BRING AT
LEAST A MODERATE EAST GAP WIND INTO PORTIONS OF THE RIO GRANDE
VALLEY AND THUS DEW POINTS WILL RECOVER EAST OF THE CENTRAL
MOUNTAIN CHAIN AND TO A LESSER DEGREE INTO THE RIO GRANDE VALLEY FOR
WED.
THE WED TO THU PERIOD SHOULD FEATURE LITTLE OR NO THUNDER IN THE
FCST AREA. EXPECT WARMING TEMPERATURES AND SLIGHT MOISTURE INCREASE
FOR LATE WEEK AS HIGH PRESSURE BUILDS AND THE AIR MASS GRADUALLY
RECOVERS. EXCELLENT VENTILATION THE NEXT 3 TO 5 DAYS...EXCEPT THE
EAST HALF ON WED MAY ONLY REACH FAIR TO GOOD LVLS.
43
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
306 PM MDT SUN AUG 16 2015
.SYNOPSIS...
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS IS EXPECTED FOR THE
EASTERN PLAINS TONIGHT AS STORMS THIS AFTERNOON ROLL OFF THE
CENTRAL MOUNTAIN CHAIN. ON MONDAY AND TUESDAY...A BETTER CHANCE OF
SEVERE WEATHER EXISTS ACROSS NORTHEAST NEW MEXICO WHERE LARGE HAIL
AND DAMAGING WINDS WILL BE POSSIBLE. MEANWHILE...DRIER CONDITIONS
WILL PREVAIL ACROSS THE WEST. A COLD FRONT THAT RACES THROUGH THE
PLAINS TUESDAY WILL BE RESPONSIBLE FOR MUCH COOLER TEMPERATURES
ACROSS THE EAST ON WEDNESDAY...WITH MANY LOCALES STRUGGLING TO
REACH 80. DRIER WEATHER IS IN STORE AREA WIDE FOR WEDNESDAY AND
THURSDAY.
&&
.DISCUSSION...
CONVECTION IS NOT QUITE AS ROBUST TODAY AS IT WAS YDAY AT THIS
TIME. THIS MAY BE OWING TO A COOLER START DUE TO REMNANT CLOUD
COVER THIS MORNING...AND PERHAPS MORESO...THERE IS SOME EVIDENCE
ON WV SATELLITE OF DRIER AIR MOVING IN FROM THE WEST. REMNANT
MOISTURE PLUME LOOKS TO BE STRETCHING ACROSS THE EAST...AND
ALONG/EAST OF THE CENTRAL MTN CHAIN WILL BE THE FAVORED AREA FOR
STORMS THROUGH TONIGHT. SIMILAR TO YESTERDAY...THE HRRR SHOWS A
CLUSTER OF STORMS ACROSS THE PLAINS LATE THIS EVENING. A FEW
STORMS MAY BE STRONG OR SEVERE...OR MAY CREATE LOCALIZED FLOODING
ISSUES. HAVE INCREASED POPS ACCORDINGLY ONCE AGAIN.
MONDAY LOOKS TO BE A BIT MORE FAVORED FOR SEVERE WX ACROSS THE
NORTHEAST AS THE NOSE OF AN UPPER LEVEL JET PUSHES INTO COLORADO
AND NORTHERN NM...INCREASING SHEAR. SHOULD STILL BE PLENTY OF LOW
LEVEL MOISTURE AROUND...AND CAPE VALUES SHOULD BE SIMILAR TO THIS
AFTN...BETWEEN 1000-1500 J/KG. THUS...THE ADDED SHEAR WILL BE THE
MAIN FACTOR INCREASING SEVERE CHANCES. LARGE HAIL AND DAMAGING
WIND GUSTS WILL BE THE MAIN THREATS. FURTHER SOUTH ACROSS THE
PLAINS...STORM COVERAGE WILL BE MUCH LESS...BUT COULD STILL SEE A
STRONG STORM OR TWO DEVELOP.
THE UPPER LEVEL TROUGH THAT WE HAVE BEEN ADVERTISING WILL CROSS
THE CENTRAL ROCKIES MONDAY NIGHT AND EARLY TUESDAY...WITH AN
ASSOCIATED PACIFIC FRONT SLIDING FROM NW TO SE ACROSS NM. FOR A
CHANGE..IT WILL ACTUALLY BE BREEZY TO WINDY ACROSS MUCH OF NW NM.
STRUGGLED WITH WHAT TO DO WITH HIGH TEMPS ACROSS THE CENTRAL AND
WEST. THE DRIER AIR WOULD SUGGEST WARMER...BUT LOWER
HEIGHTS/COOLER 700MB TEMPS WOULD SUGGEST COOLER. LATER ON TUESDAY
MORNING THRU TUESDAY AFTN...THE MORE SUBSTANTIAL BACK DOOR FRONT
WILL SLIDE DOWN THE PLAINS AND MODELS ARE NOW ADVERTISING IT WILL
PUSH THRU THE GAPS OF THE CENTRAL MTN CHAIN TUESDAY NIGHT. LOW
LEVEL MOISTURE WILL BE REPLENISHED BEHIND THE BACK DOOR
FRONT...AFTER IT WAS SCOURED OUT BY THE PACIFIC FRONT. UPSLOPE
FLOW AND CONTINUED INSTABILITY SHOULD YIELD SCATTERED STORMS
ACROSS AT LEAST THE NE. ONCE AGAIN...A FEW STORMS MAY BE STRONG OR
SEVERE.
AFTER THE TROUGH PASSAGE...MUCH DRIER MID LEVEL AIR WILL BE IN
PLACE ACROSS THE LAND OF ENCHANTMENT...SIGNIFICANTLY LIMITING
PRECIP CHANCES FOR WEDNESDAY. ANY STORM WILL BE HARD TO COME
BY...DESPITE THE LOW LEVEL MOISTURE NOT ENTIRELY MIXING OUT ACROSS
THE PLAINS. ADDITIONALLY...IT WILL BE SIGNIFICANTLY COOLER ACROSS
THE EAST ON WEDNESDAY BEHIND THE FRONT WITH MANY AREAS STRUGGLING
TO REACH 80F. THE DRY WX WILL CONTINUE ON THURSDAY...THEN MODELS
CONTINUE TO STRUGGLE WITH THE UPPER AIR PATTERN. THE EC SHOWS
ANOTHER STRONG TROUGH ACROSS THE CENTRAL ROCKIES ON
SATURDAY...WITH DRIER AIR CONTINUING TO FILTER INTO NM. THE GFS
HAS THIS TROUGH MUCH FURTHER NORTH WITH THE UPPER HIGH TRYING TO
REBUILD OVER THE SW CONUS...PERHAPS ALLOWING FOR SOME MOISTURE
SEEPAGE. BEHIND THIS AFOREMENTIONED TROUGH...ANOTHER BACK DOOR
FRONT SHOULD REPLENISH LOW LEVEL MOISTURE ACROSS THE PLAINS SAT
NIGHT/SUN. BUT WITHOUT A S OR SWLY FLOW ALOFT...THINK THE GFS IS
OVERDOING THE MOISTURE FLUX/QPF IN THE EXTENDED...AT LEAST THURS
NIGHT-SAT. STAY TUNED.
34
&&
.FIRE WEATHER...
UPPER HIGH CENTER HAS DRIFTED FARTHER WEST INTO ARIZONA AND
CIRCULATION ATTEMPTING TO PUSH SOME DRIER MID LEVEL AIR INTO THE
FOUR CORNERS REGION. THE DRYING TREND OVER WESTERN AND CENTRAL NM
BECOMES MORE PRONOUNCED BY MID TO LATE WEEK AS A DISTURBANCE SWEEPS
OUT OF THE NORTHERN ROCKIES AND NORTHWEST FLOW PREDOMINATES OVER NM.
VERY SPOTTY CRITICAL CONDITIONS POSSIBLE FROM THE NORTHWEST PLATEAU
TO THE CENTRAL HIGHLANDS TUESDAY AFTERNOON.
A SURFACE FRONT TUESDAY NIGHT WILL PUSH HIGHER DEW POINTS INTO THE
RGV BUT THEY SHOULD MIX OUT WEDNESDAY. ANOTHER FRONT LATE IN THE
WEEK OR OVER THE WEEKEND COULD REPLENISH LOW LEVEL MOISTURE CENTRAL
AND EAST...BUT BY THEN...A SPRAWLING RIDGE ALOFT COULD STEER THE
MAJORITY OF MONSOON MOISTURE AWAY FROM NM.
CONVECTION ALREADY GOING BY MIDDAY OVER THE NORTHERN AND WESTERN
HIGH TERRAIN. CELL MOTION TO THE SOUTH AND SOUTHWEST...WITH SHORT
TERM MODELS INDICATING THE EASTERN PLAINS WILL SEE RAIN THIS EVENING
AND OVERNIGHT...AFTER STORMS GET GOING OVER SE CO. POTENTIAL FOR
ISOLD STRONG TO SEVERE STORMS NE. ALSO LOOKING FOR A CONVECTIVELY
DRIVEN EAST WIND INTO THE RGV TONIGHT. MONDAY INTO TUESDAY WILL SEE
POTENTIAL FOR ISOLATED STRONG TO SEVERE STORMS FROM THE CENTRAL MT
CHAIN EASTWARD. THE BATTLE OF THE DRY IN THE WEST AND THE WET IN THE
EAST BECOMES SHARPER TUESDAY...WITH ONLY ISOLATED CONVECTION
FORECAST WEST. HIGH HAINES FORECAST TO BE WIDESPREAD OVER THE
CENTRAL AND WEST TUESDAY...AND OVER NEARLY ALL OF THE FORECAST AREA
THURSDAY AND FRIDAY. OVERALL...OVERNIGHT RH TRENDS WILL BE LESS
GENEROUS WEST AND CENTRAL AS THE WORK WEEK PROGRESSES...AND AFTERNOON
MIN RH VALUES WILL DECREASE AS WELL. HIGHS WILL GENERALLY BE NEAR TO
ABOVE AVERAGE...EXCEPT IN THE EAST WEDNESDAY IN THE WAKE OF
TUESDAY/S FRONT.
CONVECTION TAPERS OFF WEDNESDAY/THURSDAY WITH A FEW MOSTLY DIURNAL
STORMS OVER THE HIGHER TERRAIN...BUT SLOWLY INCREASES IN AREAL
COVERAGE INTO THE WEEKEND.
ECMWF A LITTLE SLOWER THAN GFS DEVELOPING THE MASSIVE RIDGE ALOFT
EARLY NEXT WEEK...BY 240 HRS IT HAS A MUCH STRONGER TROF OVER THE
NRN ROCKIES AND POSSIBLY A BETTER FETCH OF MOISTURE INTO NM FROM OLD
MEXICO. SO INCREASING UNCERTAINTY IN THE FORECAST WITH TIME.
&&
.AVIATION...
18Z TAF CYCLE
UPPER HIGH CENTERED OVR CENTRAL AND ERN AZ WITH NORTH TO
NORTHWEST WINDS ALF OVR NM. DRIER MID LEVEL AIR PUSHING INTO THE
FOUR CORNERS SHOULD LIMIT CONVECTION THERE WHILE CONVECTION
DEVELOPS OVR THE REMAINDER OF THE HIGHER TERRAIN AND SLOWLY SPREADS
INTO THE LOWER ELEVATIONS...INCLUDING THE ERN PLAINS. BRIEF MVFR
CIGS/VSBYS IN STRONGER STORMS WITH HEAVY RAIN...WIND GUSTS TO
AROUND 45KT AND SMALL HAIL WILL OCCASIONALLY OBSCURE TERRAIN.
AFT 06Z PATCHY LOW CLOUDS/FOG POSSIBLE FROM EAST SLOPES OF
CENTRAL MT CHAIN OVER THE PLAINS.
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 62 95 59 93 / 0 5 5 0
DULCE........................... 52 88 50 85 / 10 10 10 5
CUBA............................ 55 86 54 83 / 10 10 10 5
GALLUP.......................... 53 92 56 91 / 5 5 5 0
EL MORRO........................ 54 88 53 87 / 5 10 5 0
GRANTS.......................... 54 90 56 89 / 10 5 5 0
QUEMADO......................... 55 88 55 86 / 20 10 10 5
GLENWOOD........................ 60 94 59 92 / 30 20 20 5
CHAMA........................... 49 81 46 78 / 20 30 20 5
LOS ALAMOS...................... 60 86 61 85 / 20 30 20 10
PECOS........................... 57 83 58 84 / 40 40 30 10
CERRO/QUESTA.................... 55 79 53 78 / 40 40 20 20
RED RIVER....................... 45 73 44 72 / 50 60 40 30
ANGEL FIRE...................... 48 73 48 73 / 50 60 40 30
TAOS............................ 53 82 52 82 / 30 30 10 10
MORA............................ 54 79 54 80 / 60 50 40 20
ESPANOLA........................ 58 90 58 90 / 20 10 10 5
SANTA FE........................ 61 85 61 85 / 30 30 20 10
SANTA FE AIRPORT................ 59 90 60 89 / 20 10 10 0
ALBUQUERQUE FOOTHILLS........... 66 93 65 93 / 20 10 10 0
ALBUQUERQUE HEIGHTS............. 69 95 67 96 / 20 5 5 0
ALBUQUERQUE VALLEY.............. 65 96 64 97 / 20 5 5 0
ALBUQUERQUE WEST MESA........... 66 95 66 95 / 20 5 5 0
LOS LUNAS....................... 65 96 64 97 / 20 5 5 5
RIO RANCHO...................... 66 96 66 95 / 20 5 5 0
SOCORRO......................... 65 98 67 99 / 20 10 10 5
SANDIA PARK/CEDAR CREST......... 59 88 59 86 / 20 20 20 0
TIJERAS......................... 61 90 61 91 / 20 10 20 5
MORIARTY/ESTANCIA............... 55 88 56 90 / 30 20 20 5
CLINES CORNERS.................. 58 86 59 86 / 40 30 30 5
GRAN QUIVIRA.................... 59 88 61 89 / 30 30 20 5
CARRIZOZO....................... 63 91 64 92 / 30 20 20 5
RUIDOSO......................... 59 81 61 84 / 30 40 30 20
CAPULIN......................... 58 83 57 81 / 50 60 50 30
RATON........................... 56 86 55 83 / 60 60 40 30
SPRINGER........................ 57 87 57 85 / 60 60 40 20
LAS VEGAS....................... 55 84 56 85 / 60 50 40 20
CLAYTON......................... 64 87 62 83 / 50 60 60 30
ROY............................. 61 85 60 84 / 60 50 50 20
CONCHAS......................... 68 92 66 92 / 60 40 50 20
SANTA ROSA...................... 65 93 65 93 / 50 30 40 10
TUCUMCARI....................... 68 93 67 93 / 60 20 50 20
CLOVIS.......................... 66 91 65 92 / 50 10 30 10
PORTALES........................ 66 92 65 93 / 50 10 20 10
FORT SUMNER..................... 68 93 68 95 / 50 20 20 10
ROSWELL......................... 69 97 70 100 / 30 10 20 10
PICACHO......................... 64 92 64 94 / 30 30 20 10
ELK............................. 62 84 64 88 / 30 40 20 10
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
34
AREA FORECAST DISCUSSION
NWS RALEIGH NC
255 AM EDT SUN AUG 16 2015
.SYNOPSIS...WEAK SURFACE HIGH PRESSURE WILL HOLD OVER THE REGION
THROUGH THE REST OF THE WEEKEND. AN APPROACHING UPPER LEVEL
DISTURBANCE WILL BRING INCREASING CHANCES FOR SHOWERS AND
THUNDERSTORMS BY TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 935 PM SATURDAY...
ISOLATED SHOWERS REMAIN ONGOING IN TEH FAR SOUTHWESTERN COUNTIES BUT
OTHERWISE ALL OTHER CONVECTION HAS CEASED AT THIS TIME. LOOKING AT
THE SPC MESOANALYSIS FOR THE REGION...A LOT OF CIN HAS DEVELOPED
OVER MUCH OF THE AREA BUT A BULLSEYE OF STILL VERY STRONG LOW LEVEL
LAPSE RATES EXISTS OVER THE EXTREME SOUTHWESTERN COUNTIES AND MOST
LIKELY ACCOUNTS FOR MUCH OF THE SHOWER ACTIVITY STILL REMAINING IN
THE AREA. DESPITE THE RAP MODEL DEPICTION OF CONTINUOUS LIGHT
CONVECTION IN THE WEST THROUGH THE EARLY MORNING HOUS...WOULD EXPECT
MOST IF NOT ALL SHOWER ACTIVITY TO CEASE BEFORE MIDNIGHT. EXPECT
CLOUD COVER TO LINGER IN THE WEST WHILE EASTERN AREAS SHOULD CLEAR
OUT. AS A RESULT...SOME FOG IS POSSIBLE IN EASTERN AREAS BUT LESS SO
IN THE WEST OUTSIDE OF AREAS AFFECTED BY PRIOR RAINFALL. LOWS
OVERNIGHT SHOULD BE IN THE MID TO UPPER 60S ACROSS THE AREA WITH
CALM TO VERY LIGHT WINDS.
&&
.SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
AS OF 245 PM SATURDAY...
DESPITE THEIR TYPICAL DIFFERENCES OVER THE LAST COUPLE OF DAYS OR
SO...WITH THE NAM SHOWING GREATER INSTABILITY AND THE GFS LESS...
BOTH SETS OF GUIDANCE SUPPORT GREATER MOISTURE OVER THE WESTERN
PIEDMONT. PRECIPITABLE WATER VALUES ARE FORECAST NEAR 1.5 INCHES
TOWARD THE YADKIN RIVER...LESS TOWARD KRWI WHERE K INDICES SUNDAY
REMAIN IN THE TEENS AT BEST. MUCAPE IS FORECAST ON THE GFS BETWEEN
1000 AND 1500J/KG OVER THE WESTERN PIEDMONT LATE SUNDAY AFTERNOON...
BARELY REGISTERING ALONG AND EAST OF U.S. 1. THE SURFACE PATTERN
REMAINS SIMILAR TO TODAY..WEAK HIGH PRESSURE WITH A WEAK PIEDMONT
TROUGH. ALOFT...WITH BROAD RIDGING...WINDS ARE NOT VERY STRONG AT
ALL WITH ANY SHORTWAVE WEAK ALONG WITH DIFFLUENCE. PLAN TO FORECAST
BASICALLY PERSISTENCE...DIMINISHED CLOUDS FOR A TIME IN THE MORNING
FOLLOWED BY SOME AFTERNOON CU AND THE POTENTIAL FOR ISOLATED SHOWERS
ALONG AND WEST OF A LINE FROM ABOUT KBUY TO NEAR KFAY...POSSIBLY
JUST A TOUCH FARTHER EAST THAN TODAY BASED ON THE AVAILABLE MOISTURE
CREEPING EAST REDUCING STABILITY. CONTINUE TO ANTICIPATE ANY
ISOLATED SHOWER DIMINISHING DURING THE EVENING ALTHOUGH ANY SHOWER
COULD LINGER A LITTLE LONGER INTO THE OVERNIGHT AS THE CAP AROUND
AND JUST ABOVE 700MB ON GFS BUFR SOUNDINGS BECOMES LESS SHARP IN ITS
ORIENTATION. AFTER DAYTIME HIGHS WITHIN A DEGREE OR THREE OF 90...
OVERNIGHT LOWS SUNDAY NIGHT 65 TO 70.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 255 AM SUNDAY...
A RATHER WEAK MID MISSISSIPPI VALLEY SHORT WAVE WILL BE LIFTING
NORTHEAST THEN EAST ACROSS THE AREA IN THE LATE MONDAY THROUGH
TUESDAY TIME FRAME. STILL SOME LOW CONFIDENCE IN THE WINDOW OF BEST
OPPORTUNITY FOR POPS WITH ABOUT A 12 HOUR TIMING DIFFERENCE IN MODEL
SOLUTIONS. REGARDLESS...POPS DURING THE FAVORABLE DIURNAL WINDOW ON
TUESDAY WILL BE IN THE CHANCE RANGE WITH CONSIDERABLE CLOUDINESS TO
HAMPER INSOLATION. HAVE LOWERED HIGHS A BIT...86 WEST TO 89 EAST...
AND WE MAY WIND UP ADJUSTING THEM DOWN FURTHER IN LATER FORECASTS
CONSIDERING THE HEAVY CLOUDINESS EXPECTED.
TRANSITION TO A CENTRAL CONUS TROF/EAST COAST RIDGE IN THE MID TO
LATE WEEK WILL INCREASE MOISTURE ACROSS THE AREA...WITH PW/S ON THE
ORDER OF 2 INCHES IN DEEP SOUTHWEST FLOW. FORCING MECHANISMS WILL BE
WEAK THROUGH FRIDAY...BUT WOULD EXPECT AT LEAST SCATTERED CONVECTION
DURING MAX HEATING AS HIGHS REACH UPPER 80S TO LOWER 90S WED AND THU.
CONFIDENCE DIMINISHES FURTHER TOWARDS THE WEEKEND AS THE SURFACE
FRONT ASSOCIATED WITH THE DAMPENING CENTRAL CONUS TROF WILL MOVE
INTO THE AREA THURSDAY NIGHT. IT WILL SLOW AND REORIENT WITH THE
SOUTHWEST UPPER FLOW ON FRIDAY AS THE UPPER VORT AXIS SHEARS OUT
WITH THE UPPER TROF LIFTING NORTHEAST INTO THE GREAT LAKES AREA.
THIS WILL INCREASE RAIN CHANCES FRIDAY AND PERHAPS SATURDAY AS WELL
AS WEAK IMPULSES IN THE PREDOMINANT SOUTHWEST FLOW WILL BE ALIGNED
MORE FAVORABLY WITH THE SURFACE FRONT. HIGHS FRI AND SAT AGAIN
MAINLY UPPER 80S TO LOW 90S WITH POPS IN THE 40 PERCENT RANGE.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
AS OF 745 PM SUNDAY...
VFR CONDITIONS ARE LIKELY TO DOMINATE AT ALL CENTRAL NC TERMINAL
FORECAST SITES THROUGH THE NEXT 24 HOURS. VERY WEAK WINDS FROM THE
SURFACE ON UP THROUGH THE MID LEVELS COMBINED WITH LOWER-THAN-USUAL
MOISTURE AND A LACK OF STRONG WEATHER FEATURES WILL LEAD TO
GENERALLY DRY WEATHER. THERE IS HOWEVER A SMALL CHANCE OF A STRAY
STORM PASSING NEAR INT SUN AFTERNOON... AS WAS THE CASE EARLIER THIS
EVENING... AS STORMS FORM OVER THE MOUNTAINS/FOOTHILLS AND DRIFT
TOWARD THE PIEDMONT. BUT THE CHANCES ARE TOO LOW AT THIS TIME TO
INCLUDE IN THE TAF. THERE IS ALSO A RISK OF MVFR FOG AT ANY TAF SITE
LATE TONIGHT... MAINLY BETWEEN 08Z AND 12Z. SURFACE WINDS WILL
REMAIN VARIABLE AT 5 KTS OR LESS.
LOOKING BEYOND 00Z MON (SUN EVENING)... VFR CONDITIONS SHOULD HOLD
INTO MONDAY WITH LITTLE CHANGE IN PATTERN... ALTHOUGH THE RISK OF
SUB-VFR FOG WILL BE A LITTLE GREATER LATE SUN NIGHT INTO EARLY MON
MORNING. INCREASING SOUTHWEST FLOW ALOFT AND AN UPPER LEVEL
DISTURBANCE MOVING IN FROM THE WEST WILL BRING INCREASING CHANCES
FOR SHOWERS AND STORMS ALONG WITH A GROWING RISK OF SUB-VFR
CONDITIONS STARTING MON NIGHT... MAINLY EACH AFTERNOON AND
EVENING... LASTING AT LEAST INTO THU. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...ELLIS
SHORT TERM...DJF
LONG TERM...MLM
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
947 PM CDT MON AUG 17 2015
.UPDATE...
ISSUED AT 947 PM CDT MON AUG 17 2015
SHOWERS WITH ISOLATED THUNDERSTORMS CONTINUE TO MOVE SLOWLY EAST
FROM THE SOUTHWEST PART OF THE STATE. THE MAIN QUESTION TONIGHT IS
HOW FAR NORTH TO GO WITH THE HIGHER POPS. THE LATEST 00Z NAM
SUGGESTS MOST OF THE RAIN WILL BE CONFINED TO THE ND / SD
BORDER...WHILE THE RAP AND HRRR STILL BRING IT NORTH OF I94. HAVE
INCREASED POPS IN THE SOUTH AND WEST TO CATEGORICAL...BUT TAPER
THEM RELATIVELY QUICKLY FARTHER NORTH.
UPDATE ISSUED AT 655 PM CDT MON AUG 17 2015
REGIONAL RADAR MOSAIC SHOWS SHOWERS AND ISOLATED THUNDERSTORMS
MOVING ACROSS SOUTHEAST MONTANA TOWARDS SOUTHWEST NORTH DAKOTA
AND NORTHWEST SOUTH DAKOTA. INSTABILITY ACROSS NORTH DAKOTA
REMAINS LIMITED...SO KEEPING THE MENTION OF THUNDERSTORMS AS
ISOLATED LOOKS REASONABLE. THE LATEST SHORT TERM MODELS STILL
FOCUS THE BEST RAIN CHANCES IN THE SOUTHWEST PART OF THE STATE
THIS EVENING...AND THE CURRENT FORECAST HAS THAT SCENARIO WELL
COVERED.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 342 PM CDT MON AUG 17 2015
CURRENT SURFACE ANALYSIS PLACES COOL HIGH PRESSURE OVER THE
NORTHERN PLAINS. UPPER LEVEL ANALYSIS PLACES BROAD TROUGH OVER THE
NORTH-CENTRAL CONUS WITH POTENT SHORT WAVE DIGGING OVER THE
NORTHERN ROCKIES INTO THE PLAINS. OVER OUR AREA...A FEW SHOWERS
CONTINUE OVER NORTH CENTRAL NORTH DAKOTA WITH A LITTLE JET STREAK
PASSING OVER...WHILE SHOWERS START TO WORK INTO THE WEST WITH THE
AFOREMENTIONED DIGGING SHORT WAVE.
FOR THE REMAINDER OF THIS AFTERNOON INTO TONIGHT...SHORT WAVE WILL
CONTINUE TO DIG TO THE SOUTHEAST WITH A BROAD AREA OF
PRECIPITATION DEVELOPING...PARTICULARLY OVER SOUTHEAST
MONTANA/EASTERN WYOMING INTO SOUTH DAKOTA. OUR AREA WILL BE ON THE
NORTHERN FRINGES WITH THE GREATEST PRECIPITATION CHANCES REMAINING
ALONG THE FAR SOUTHERN TIER OF THE STATE...DECREASING CHANCES
TOWARDS THE NORTH. INSTABILITY REMAINS LOW...THOUGH ENOUGH EXITS
FOR A FEW WEAKER THUNDERSTORMS TO DEVELOP.
ON TUESDAY...SYSTEM WILL CONTINUE ITS EASTERLY TRACK...CLOSING OFF
OVER EASTERN SOUTH DAKOTA. THIS WILL CONTINUE TO KEEP THE HIGHEST
CHANCES ALONG THE SOUTHERN TIER OF THE STATE. TEMPERATURES WILL BE
QUITE COOL FOR THIS TIME OF YEAR...WITH HIGHS SOUTH OF I-94
REMAINING IN THE 60S...WHILE AREAS TO THE NORTH MAY PUSH INTO THE
LOWER 70S.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 342 PM CDT MON AUG 17 2015
CHANCES FOR SHOWERS AND THUNDERSTORMS WILL LINGER INTO TUESDAY
NIGHT...AS A BROAD UPPER LEVEL TROUGH CONTINUES DIGGING EASTWARD
ACROSS THE NORTHERN PLAINS.
A SLOW WARMING TREND AND DRY WEATHER ARE EXPECTED WEDNESDAY INTO
EARLY FRIDAY...AS AN UPPER LEVEL SHORTWAVE RIDGE IS PROJECTED
EAST ACROSS THE AREA.
THE NEXT UPPER LEVEL TROUGH IS EXPECTED TO MOVE INTO THE NORTH
PLAINS BY LATE FRIDAY...BRINGING ANOTHER ROUND OF THUNDERSTORMS TO
THE STATE BY LATE FRIDAY INTO EARLY SUNDAY MORNING...HIGHLIGHTED
WELL WITHIN THE LONG RANGE MODELS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 655 PM CDT MON AUG 17 2015
HAVE KEPT A VFR FORECAST IN PLACE AT THE TERMINALS...BUT THERE IS
SOME CONCERN A FEW SHOWERS COULD CREATE MVFR CONDITIONS AT TIMES.
THIS CONCERN IS MAINLY FOR THE SOUTHERN AERODROMES...ESPECIALLY
AT KDIK THIS EVENING. HAVE INTRODUCED A PERIOD OF LIGHT RAIN AT
KDIK TONIGHT...AND WILL MONITOR IN CASE CIGS / VIS DROP BELOW
CURRENT FORECAST.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CK
SHORT TERM...JJS
LONG TERM...AC
AVIATION...CK
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1110 AM MDT SUN AUG 16 2015
.UPDATE...
ISSUED AT 929 AM MDT SUN AUG 16 2015
WESTERLY FLOW IS ADVECTING SMOKE FROM PACIFIC NORTHWEST FIRES INTO
THE CWA THIS MORNING. VISIBILITIES ARE SLIGHTLY REDUCED TO 9 MI AT
GCC AND 8 MI AT RAP UNDER AREAS OF SMOKE. ADDED PATCHY SMOKE TO
THE FORECAST FOR EARLY THIS AFTERNOON. WEAK UPPER WAVE CONTINUES
TO PRODUCE SHOWERS AND THUNDERSTORMS ACROSS EASTERN SD...WITH THE
NEXT WAVE APPROACHING FROM WY. ADJUSTED SKY AND POP GRIDS TO
REFLECT CURRENT TRENDS. UNDER MOSTLY CLOUDY/SMOKY SKIES...TEMPS
ARE IN THE 60S TO LOWER 70S.
&&
.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 253 AM MDT SUN AUG 16 2015
UPPER LEVEL ANALYSIS HAS RIDGING OVER THE FAR SW CONUS WITH BROAD
TROF ACROSS THE NORTHERN ROCKIES AND FAR NORTHERN PLAINS. SKIES
ARE VARIABLY CLOUDY ACROSS THE NORTHERN PLAINS WITH A COUPLE AREAS
OF SHOWERS AND THUNDERSTORMS...ONE OVER NORTHWEST SD...AND ANOTHER
OVER SOUTH CENTRAL SD. AT THE SURFACE...LOW PRESSURE IS LOCATED
ACROSS EASTERN SOUTH DAKOTA WITH COLD FRONT TRAILING ACROSS FAR
SOUTHWEST SOUTH DAKOTA. TEMPERATURES AT 3AM ARE GENERALLY IN THE
MID 60S TO MID 70S...WITH LIGHT NORTHERLY WINDS.
TODAY...BROAD UPPER LEVEL TROF WILL SLOWLY SHIFT EAST...WITH
SURFACE COLD FRONT SAGGING SOUTH INTO NEBRASKA. LINGERING SHOWERS
AND THUNDERSTORMS ACROSS FAR NORTHWEST AND FAR SOUTH CENTRAL SD
WILL SLOWLY SHIFT EAST WITH PARTLY CLOUDY SKIES EXPECTED MOST
AREAS BY AFTERNOON. WINDS WILL REMAIN LIGHT NORTHERLY THIS MORNING
AND SHIFTING TO THE NORTHEAST THIS AFTERNOON AS SURFACE HIGH
PRESSURE DROPS INTO MONTANA. HIGH TEMPERATURES TODAY WILL BE MUCH
COOLER THAN YESTERDAY...IN THE 70S TO LOWER 80S.
TONIGHT...BROAD UPPER LEVEL TROF WILL REMAIN OVER THE NORTHERN
PLAINS AS SECONDARY SHORTWAVE MOVES INTO THE AREA...BRINGING MORE
CHANCES OF SHOWERS AND STORMS. BEST CHANCES WILL BE ACROSS
NORTHEAST WYOMING AND THE BLACK HILLS AREA. LOW TEMPERATURES WILL
COOL INTO THE 50S.
ON MONDAY...AXIS OF UPPER LEVEL TROF WILL MOVE INTO THE AREA LATE
IN THE DAY...BRINGING BETTER CHANCES FOR WIDESPREAD RAIN SHOWERS
AND ISOLATED THUNDERSTORMS...ALONG WITH COOL TEMPERATURES. HIGH
TEMPERATURES ON MONDAY ARE ONLY EXPECTED TO BE IN THE MID 60S TO
MID 70S UNDER CLOUDY SKIES. PRECIP CHANCES INCREASE ACROSS THE
ENTIRE AREA LATE MONDAY INTO MONDAY NIGHT AS THE UPPER TROF AXIS
SHIFTS EAST. WIDESPREAD PRECIP SHOULD FALL ACROSS THE AREA MONDAY
NIGHT...WITH EARLY ESTIMATES OF 0.25 TO 0.50 INCHES ACROSS
NORTHWEST SOUTH DAKOTA...AND 0.50 TO 1.25 INCHES OF RAIN FROM
NORTHEAST WYOMING...THROUGH THE BLACK HILLS...AND ACROSS SOUTHWEST
TO SOUTH CENTRAL SOUTH DAKOTA. LOW TEMPERATURES MONDAY NIGHT WILL
BE COOL ACROSS THE AREA...MAINLY IN THE 50S...WITH SOME 40S ACROSS
THE BLACK HILLS.
.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 253 AM MDT SUN AUG 16 2015
STRONG TROUGH WILL MOVE INTO EASTERN DAKOTAS TUESDAY...WITH BEST
Q-G FORCING DURING FIRST HALF OF DAY. SHOWERS MAY LINGER INTO
TUESDAY EVENING AS WEAKER WAVE DROPS DOWN BACK SIDE OF TROF. WITH
CLOUDS/PRECIPITATION TEMPERATURES WILL BE WELL BELOW AVERAGE. DRY
NORTHWEST FLOW ACROSS THE AREA FOR WEDNESDAY/THURSDAY...ALONG
WITH WARMER TEMPERATURES. LOW CONFIDENCE IN FORECAST FOR THIS
WEEKEND. 00Z ECMWF HAS COMPACT UPPER LOW TRACKING THROUGH THE
DAKOTAS...WHILE GFS HAS PROGRESSIVE/FLAT TROF THROUGH THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY)
ISSUED AT 1107 AM MDT SUN AUG 16 2015
VFR CONDITIONS ARE EXPECTED UNTIL ABOUT 06Z. AT THAT TIME MVFR
CIGS WILL BE DEVELOPING OVER NERN WY...THE BLKHLS...AND FAR SWRN
SD...AS AN UPPER TROUGH APPROACHES. CLOUDS WILL SLOWLY LOWER TO
AREAS OF IFR CIGS FROM 12-18Z MONDAY OVER THE SAME AREA. SCT SHRA
ALSO EXPECTED TO DEVELOP LATE EARLY THIS EVNG OVER NERN WY AND
SPREAD ACROSS WRN SD OVERNIGHT INTO MONDAY MRNG.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
UPDATE...POJORLIE
SHORT TERM...15
LONG TERM...7
AVIATION...BUNKERS
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
938 AM MDT SUN AUG 16 2015
.UPDATE...
ISSUED AT 929 AM MDT SUN AUG 16 2015
WESTERLY FLOW IS ADVECTING SMOKE FROM PACIFIC NORTHWEST FIRES INTO
THE CWA THIS MORNING. VISIBILITIES ARE SLIGHTLY REDUCED TO 9 MI AT
GCC AND 8 MI AT RAP UNDER AREAS OF SMOKE. ADDED PATCHY SMOKE TO
THE FORECAST FOR EARLY THIS AFTERNOON. WEAK UPPER WAVE CONTINUES
TO PRODUCE SHOWERS AND THUNDERSTORMS ACROSS EASTERN SD...WITH THE
NEXT WAVE APPROACHING FROM WY. ADJUSTED SKY AND POP GRIDS TO
REFLECT CURRENT TRENDS. UNDER MOSTLY CLOUDY/SMOKY SKIES...TEMPS
ARE IN THE 60S TO LOWER 70S.
&&
.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 253 AM MDT SUN AUG 16 2015
UPPER LEVEL ANALYSIS HAS RIDGING OVER THE FAR SW CONUS WITH BROAD
TROF ACROSS THE NORTHERN ROCKIES AND FAR NORTHERN PLAINS. SKIES
ARE VARIABLY CLOUDY ACROSS THE NORTHERN PLAINS WITH A COUPLE AREAS
OF SHOWERS AND THUNDERSTORMS...ONE OVER NORTHWEST SD...AND ANOTHER
OVER SOUTH CENTRAL SD. AT THE SURFACE...LOW PRESSURE IS LOCATED
ACROSS EASTERN SOUTH DAKOTA WITH COLD FRONT TRAILING ACROSS FAR
SOUTHWEST SOUTH DAKOTA. TEMPERATURES AT 3AM ARE GENERALLY IN THE
MID 60S TO MID 70S...WITH LIGHT NORTHERLY WINDS.
TODAY...BROAD UPPER LEVEL TROF WILL SLOWLY SHIFT EAST...WITH
SURFACE COLD FRONT SAGGING SOUTH INTO NEBRASKA. LINGERING SHOWERS
AND THUNDERSTORMS ACROSS FAR NORTHWEST AND FAR SOUTH CENTRAL SD
WILL SLOWLY SHIFT EAST WITH PARTLY CLOUDY SKIES EXPECTED MOST
AREAS BY AFTERNOON. WINDS WILL REMAIN LIGHT NORTHERLY THIS MORNING
AND SHIFTING TO THE NORTHEAST THIS AFTERNOON AS SURFACE HIGH
PRESSURE DROPS INTO MONTANA. HIGH TEMPERATURES TODAY WILL BE MUCH
COOLER THAN YESTERDAY...IN THE 70S TO LOWER 80S.
TONIGHT...BROAD UPPER LEVEL TROF WILL REMAIN OVER THE NORTHERN
PLAINS AS SECONDARY SHORTWAVE MOVES INTO THE AREA...BRINGING MORE
CHANCES OF SHOWERS AND STORMS. BEST CHANCES WILL BE ACROSS
NORTHEAST WYOMING AND THE BLACK HILLS AREA. LOW TEMPERATURES WILL
COOL INTO THE 50S.
ON MONDAY...AXIS OF UPPER LEVEL TROF WILL MOVE INTO THE AREA LATE
IN THE DAY...BRINGING BETTER CHANCES FOR WIDESPREAD RAIN SHOWERS
AND ISOLATED THUNDERSTORMS...ALONG WITH COOL TEMPERATURES. HIGH
TEMPERATURES ON MONDAY ARE ONLY EXPECTED TO BE IN THE MID 60S TO
MID 70S UNDER CLOUDY SKIES. PRECIP CHANCES INCREASE ACROSS THE
ENTIRE AREA LATE MONDAY INTO MONDAY NIGHT AS THE UPPER TROF AXIS
SHIFTS EAST. WIDESPREAD PRECIP SHOULD FALL ACROSS THE AREA MONDAY
NIGHT...WITH EARLY ESTIMATES OF 0.25 TO 0.50 INCHES ACROSS
NORTHWEST SOUTH DAKOTA...AND 0.50 TO 1.25 INCHES OF RAIN FROM
NORTHEAST WYOMING...THROUGH THE BLACK HILLS...AND ACROSS SOUTHWEST
TO SOUTH CENTRAL SOUTH DAKOTA. LOW TEMPERATURES MONDAY NIGHT WILL
BE COOL ACROSS THE AREA...MAINLY IN THE 50S...WITH SOME 40S ACROSS
THE BLACK HILLS.
.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 253 AM MDT SUN AUG 16 2015
STRONG TROUGH WILL MOVE INTO EASTERN DAKOTAS TUESDAY...WITH BEST
Q-G FORCING DURING FIRST HALF OF DAY. SHOWERS MAY LINGER INTO
TUESDAY EVENING AS WEAKER WAVE DROPS DOWN BACK SIDE OF TROF. WITH
CLOUDS/PRECIPITATION TEMPERATURES WILL BE WELL BELOW AVERAGE. DRY
NORTHWEST FLOW ACROSS THE AREA FOR WEDNESDAY/THURSDAY...ALONG
WITH WARMER TEMPERATURES. LOW CONFIDENCE IN FORECAST FOR THIS
WEEKEND. 00Z ECMWF HAS COMPACT UPPER LOW TRACKING THROUGH THE
DAKOTAS...WHILE GFS HAS PROGRESSIVE/FLAT TROF THROUGH THE AREA.
&&
.AVIATION...FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING
ISSUED AT 253 AM MDT SUN AUG 16 2015
ISOLD MVFR CIG/VSBY COULD OCCUR WITH ANY SHRA/TSRA...OTHERWISE
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
UPDATE...POJORLIE
SHORT TERM...15
LONG TERM...7
AVIATION...7
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
351 PM CDT SUN AUG 16 2015
.DISCUSSION...
MAIN FORECAST CONCERNS REVOLVE AROUND POWERFUL MID-LATITUDE
DISTURBANCE FORECAST TO IMPACT MUCH OF THE MID-SOUTH ON WEDNESDAY.
LEADING UP TO WEDNESDAY...AFTERNOON STORMS ARE EXPECTED DAILY...
CURRENTLY...THE PERSISTENT BUT WEAK UPPER LEVEL LOW IS STILL
MEANDERING JUST NORTHEAST OF THE MID-SOUTH THIS AFTERNOON. CURRENT
RADAR MOSAIC IS NEARLY IDENTICAL TO YESTERDAY/S WITH AN OUTFLOW
BOUNDARY APPROACHING THE MEMPHIS METRO FROM THE EAST WITH
SCATTERED THUNDERSTORMS ALONG IT. STORM MOTION IS MORE
NORTHWESTERLY THAN WESTERLY AS COMPARED TO YESTERDAY.
IN THE NEAR-TERM...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
SHOULD PERSIST THROUGH THE DURATION OF THE AFTERNOON DURING PEAK
HEATING. FOR TONIGHT...FORECAST SOUNDINGS INDICATE THAT A BAND OF
STRATUS/STRATIFORM LIGHT PRECIP WITH EMBEDDED THUNDER WILL DEVELOP
AFTER MIDNIGHT MAINLY ALONG THE TENNESSEE RIVER VALLEY. THIS LOOKS
TO BE ASSOCIATED WITH SLOW VERTICAL ASCENT WITHIN THE DIFFUSE WARM
CONVEYOR BELT OF THE UPPER LEVEL LOW. IF THIS SCENARIO UNFOLDS AS
FORECAST...HIGH TEMPERATURES MAY NEED TO BE LOWERED TOMORROW GIVEN
WIDESPREAD CLOUDINESS AND POTENTIAL PRECIP. ALREADY LOWERED
FORECAST HIGHS SOMEWHAT ACROSS THE TENNESSEE RIVER VALLEY...BUT
MAY NOT HAVE BEEN SUFFICIENT.
BY LATE MORNING...AREAS THAT DO SEE INSOLATION WILL BECOME
UNSTABLE QUICKLY AND WEAK LIFT ASSOCIATED WITH THE UPPER LOW WILL
BE SUFFICIENT FOR SCATTERED THUNDERSTORM DEVELOPMENT PRIOR TO 18Z.
IT IS HARD TO PIN DOWN EXACTLY WHERE THE GREATEST COVERAGE OF
PRECIP WILL BE TOMORROW...BUT MOST AREAS SHOULD SEE A SHOWER OR
THUNDERSTORM BY MONDAY/S END.
A SIMILAR SURFACE AND UPPER LEVEL PATTERN TO MONDAY WILL EXIST ON
TUESDAY AS WELL. LATE MORNING AND AFTERNOON STORMS ARE ONCE AGAIN
EXPECTED TO DEVELOP IN THE UNCAPPED AIRMASS WELL AHEAD OF A
DEVELOPING UPPER LEVEL TROUGH. CONTINUED THE TREND OF KEEPING
HIGHS COOLER GIVEN EXPECTED WIDESPREAD PRECIP AND CLOUD COVER
LIMITING HEATING.
FOCUS THEN SHIFTS TO WEDNESDAY AND ASSOCIATED SEVERE WEATHER
POTENTIAL. MODELS ARE IN GENERAL AGREEMENT THAT A LARGE-SCALE MEAN
TROUGH AXIS WILL SWEEP THROUGH THE CENTRAL US ON WEDNESDAY. THAT
BEING SAID...IMPORTANT DIFFERENCES DO EXIST WITH REGARD TO
PLACEMENT OF SURFACE FEATURES AND GENERAL EVOLUTION THE EVENT.
FOCUSING ON THE SYNOPTIC SETUP AND ANOMALOUS DEPTH OF THE
TROUGH FOR MID-AUGUST...ISOLATED SEVERE WEATHER SEEMS PROBABLE
WITH THE POTENTIAL FOR A WIDESPREAD EVENT STILL UNCERTAIN. THE
MOST FAVORABLE KINEMATICS WILL ALMOST CERTAINLY BE NORTH OF THE
MID-SOUTH...BUT THE NAM SUGGESTS THAT A SUBTLE LEAD IMPULSE AND
ASSOCIATED JET MAX AHEAD OF THE MEAN TROUGH WILL ROTATE THROUGH
THE MID-SOUTH. THIS SOLUTION WOULD INCREASE SEVERE WEATHER
POTENTIAL ACROSS THE REGION WITH DEEP LAYER SHEAR MUCH MORE
FAVORABLE FOR ORGANIZED CONVECTION AS COMPARED TO THE OTHER GLOBAL
MODEL SOLUTIONS. AS OF NOW...THE NAM IS THE OUTLIER WITH THIS
SOLUTION BUT IT SHOULD NOT BE DISCOUNTED AS OF YET. THERMODYNAMICS
WILL BE FAVORABLE WITH A BUOYANT WARM SECTOR AIRMASS IN PLACE.
FORECAST SOUNDINGS INDICATED MLCAPE VALUES BETWEEN 1500 - 3000
J/KG...DEPENDING ON LOCATION. DAMAGING WINDS APPEAR TO BE THE MAIN
THREAT AS OF NOW...WITH TORNADIC POTENTIAL LARGELY MITIGATED BY
WEAK/VEERED 0-2KM FLOW. CONTINUED THE TREND OF MAINTAINING LIKELY
PRECIP CHANCES...ESPECIALLY DURING THE AFTERNOON HOURS ON
WEDNESDAY.
FRONTAL PASSAGE LOOKS TO OCCUR SOMETIME WEDNESDAY...BUT IT WILL BE
SLOW TO OCCUR AS UPPER LEVEL FLOW BECOMES MORE AND MORE PARALLEL
TO THE FRONT WITH TIME. THIS WILL LIKELY MAINTAIN PRECIP ALONG AND
SOUTH OF THE I-40 CORRIDOR THROUGH THE END OF THE WEEK.
IN THE LONG-TERM...THINKING REMAINS LARGELY THE SAME. NEAR TO
BELOW NORMAL TEMPERATURES ARE EXPECTED BUT AN ACTIVE NORTHERN
STREAM LOOKS KEEP MUCH OF THE CONUS IN AN ACTIVE WEATHER REGIME
RESEMBLING LATE SPRING MUCH MORE THAN MID-AUGUST.
TVT
&&
.AVIATION...
18Z TAFS
GOES WATER VAPOR SHOWED A COMPACT UPPER LEVEL CIRCULATION CENTERED
NEAR PHT...NEARLY STATIONARY OR PERHAPS DRIVING VERY SLOWLY NORTHWEST.
EXPECT SCT SHRA/TSRA TO REMAIN NORTHEAST OF MKL THROUGH 20Z...
LIKELY EXPANDING TO THE SOUTHWEST THEREAFTER. HRRR APPEARS AT
OVERDONE INITIALLY...W/RESPECT TO TSRA COVERAGE IN THE 18Z TO 19Z
PERIOD.
LIMITED LOW LEVEL CONVERGENCE AND WEAK MIDLEVEL LAPSE RATES SHOULD
KEEP TS CHANCES LOW AT MEM...BUT LIKELY TIED TO CONVECTIVE INITIATION
OVER NORTH MS AND RESULTANT CONVECTIVE OUTFLOW BOUNDARIES.
PWB
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS MEMPHIS TN
1238 PM CDT SUN AUG 16 2015
.UPDATE...
UPDATED FOR 18Z AVIATION DISCUSSION BELOW.
&&
.PREV DISCUSSION... /ISSUED 1028 AM CDT SUN AUG 16 2015/
UPDATE...
SIMILAR TO YESTERDAY...MAIN UPDATE MADE TO THE FORECAST WAS TO
FINE-TUNE/INCREASE PRECIP CHANCES WHERE CURRENT CONVECTION IS
ONGOING...WHICH WILL LIKELY AID IN SUBSEQUENT CONVECTIVE
DEVELOPMENT LATER THIS AFTERNOON ACROSS PORTIONS OF WEST
TENNESSEE. WATER VAPOR IMAGERY DEPICTS AN UPPER LEVEL LOW LOCATED
ACROSS PORTIONS OF WEST TENNESSEE DRIFTING NORTH/NORTHWEST. THIS
MOTION SHOULD CONTINUE TODAY WHICH SHOULD ENHANCE PRECIP ALONG ITS
WESTERN/SOUTHWESTERN CONVERGENT AXIS. PRECIP WILL ONCE AGAIN WANE
AFTER SUNDOWN WITH THE LOSS OF SURFACE HEATING. TEMPERATURES
SHOULD REMAIN BELOW GUIDANCE IN AREAS WHERE PRECIP HAS/IS
OCCURRING THIS MORNING WITH OTHER AREAS REACHING THEIR FORECAST
HIGHS.
TVT
PREV DISCUSSION... /ISSUED 627 AM CDT SUN AUG 16 2015/
DISCUSSION...
THE MIDSOUTH WILL REMAIN IN AN ACTIVE WEATHER PATTERN THROUGH
FORECAST PERIOD WITH SEVERAL CHANCES OF SHOWERS AND STORMS BEFORE
A MORE ORGANIZED DISTURBANCE MOVES THROUGH THE REGION MID-WEEK.
MODELS ARE IN FAIRLY GOOD AGREEMENT THROUGHOUT THE FORECAST
PERIOD.
CURRENTLY...
SATELLITE DATA AND UPPER AIR ANALYSIS PLACE THE CENTER OF A WEAK
UPPER LOW JUST TO THE NORTH AND WEST OF THE MIDSOUTH WITH LIGHT
SOUTHERLY FLOW NEARER TO THE SURFACE. TEMPERATURES ARE 6-8
DEGREES COOLER NEAR THE TENNESSEE RIVER THAN THEY ARE NEAR AND
WEST OF THE MISSISSIPPI RIVER. AS OF 3AM... AREA RADARS HAVE THE
MIDSOUTH CLEAR OF ANY PRECIP.
SHORT TERM...
SHORT TERM MODELS HINT AT THE POSSIBLE DEVELOPMENT OF SOME MORNING
SHOWERS ASSOCIATED WITH THE AFOREMENTIONED WEAK UPPER LOW AS IT
CONTINUES TO RETROGRADE. HOWEVER... THERE IS NOT ENOUGH CONFIDENCE
TO INTRODUCE SIGNIFICANT POPS. MODELS HAVE SOMEWHAT BACKED OFF ON
COVERAGE OF CONVECTIVE STORMS THIS AFTERNOON AND EVENING WITH
BETTER CHANCES IN THE SOUTHERN AND WESTERN COUNTIES OF THE CWA.
POPS WILL INCREASE DURING THE DAY ON MONDAY AS THE WEAK UPPER LOW
MOVES NORTH AND SOUTHERLY FLOW INCREASES TRANSPORTING MORE
MOISTURE INTO THE LOWER LEVELS OF THE ATMOSPHERE. INSTABILITY
PARAMETERS ARE NOT IMPRESSIVE SO WE MAY BE LIMITED TO ONLY STRONG
NON-SEVERE STORMS. CHANCES OF THUNDERSTORMS WILL STICK AROUND INTO
MIDWEEK AS SOUTHERLY FLOW CONTINUES TO INCREASE AHEAD OF A
APPROACHING TROUGH. TEMPERATURES WILL BE NEAR MID-AUGUST NORMALS
THROUGH MID- WEEK.
LONG TERM...
MID RANGE MODELS ARE IN GOOD AGREEMENT THAT AN UPPER TROUGH WILL
DEEPEN OVER THE PLAINS AND CONTINUE TO SWING THROUGH THE
MISSISSIPPI VALLEY REGION WITH AN ASSOCIATED SURFACE LOW FORMING
IN THE CENTRAL PLAINS AND MOVING NORTHEASTWARD TOWARD THE THE
GREAT LAKES AND INTO ONTARIO. SHOWERS AND STORMS ARE LIKELY OVER
THE MIDSOUTH ON WEDNESDAY EVENING AND NIGHT AHEAD OF THE
ASSOCIATED TRAILING COLD FRONT. THE PREFRONTAL AIRMASS WILL BE
WARM AND UNSTABLE AS A LLJ PULLS WARM MOIST AIR INTO THE REGION
FROM THE GULF. THE SPC HAS THE MIDSOUTH OUTLOOKED FOR DAY 4. THE
SURFACE FRONT WILL STALL NEAR THE MIDSOUTH LEAVING US WITH CHANCES
OF SHOWERS AND THUNDERSTORMS THROUGH THE EARLY PARTS OF NEXT
WEEKEND AS UPPER LEVEL FLOW BECOMES SOUTHWESTERLY. TEMPERATURES
WEDNESDAY THROUGH SATURDAY WILL BE BELOW NORMAL VALUES.
JPM3
&&
.AVIATION...
18Z TAFS
GOES WATER VAPOR SHOWED A COMPACT UPPER LEVEL CIRCULATION CENTERED
NEAR PHT...NEARLY STATIONARY OR PERHAPS DRIVING VERY SLOWLY NORTHWEST.
EXPECT SCT SHRA/TSRA TO REMAIN NORTHEAST OF MKL THROUGH 20Z...
LIKELY EXPANDING TO THE SOUTHWEST THEREAFTER. HRRR APPEARS AT
OVERDONE INITIALLY...W/RESPECT TO TSRA COVERAGE IN THE 18Z TO 19Z
PERIOD.
LIMITED LOW LEVEL CONVERGENCE AND WEAK MIDLEVEL LAPSE RATES SHOULD
KEEP TS CHANCES LOW AT MEM...BUT LIKELY TIED TO CONVECTIVE INITIATION
OVER NORTH MS AND RESULTANT CONVECTIVE OUTFLOW BOUNDARIES.
PWB
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
830 PM CDT MON AUG 17 2015
.UPDATE...
CONVECTION HAS ENDED ACROSS THE AREA WITH THE LOSS OF DIURNAL
HEATING. AN UPDATE TO THE TEXT...GRAPHIC...AND GRID FORECAST WAS
JUST SENT TO RE-TREND VARIABLES THROUGH 12Z TUESDAY...BUT NO MAJOR
CHANGES TO THE PREVIOUS FORECAST.
&&
.PREV DISCUSSION... /ISSUED 643 PM CDT MON AUG 17 2015/
UPDATE...00Z AVIATION UPDATE BELOW.
AVIATION...VFR CONDITIONS CONTINUE THROUGH THE EVENING HOURS.
ISOLATED SHRAS WILL END AROUND SUNSET. PATCHES OF MVFR MORNING
STRATUS WERE EVIDENT THIS MORNING...AND COVERAGE SHOULD BE
SLIGHTLY GREATER OVERNIGHT AND TUESDAY MORNING. NAM BUFR SOUNDINGS
COMBINED WITH 950MB MOISTURE PROGS FROM VARIOUS MODELS INDICATE
STRATUS DEVELOPMENT ALONG THE SOUTHERN EDGE OF THE ESCARPMENT
NEAR SAT AROUND 08Z...POSSIBLY SPREADING INTO AUS TERMINAL 09Z-12Z
AS LOW LEVEL FLOW VEERS SLIGHTLY MORE SW. THERE IS A CHANCE THAT
DRT COULD SEE A PERIOD OF MVFR CEILINGS 13Z-16Z PER NAM BUFR
SOUNDINGS AND HRRR SOLUTIONS...ALTHOUGH CONFIDENCE IS LOWER THAN
I-35 SITES. STRATUS WILL SCATTER OUT QUICKLY LATE MORNING WITH VFR
CONDITIONS AGAIN TUE AFTERNOON. ISOLATED SHRAS AGAIN POSSIBLE TUE
DURING THE MID AFTERNOON AND EVENING HOURS EAST OF I-35. THESE ARE
NOT EXPECTED TO IMPACT THE I-35 TAF SITES. S AND SE FLOW LATE TUE
MORNING AND AFTERNOON WILL BE SLIGHTLY STRONGER...WITH SOME GUSTS
NEAR 20 KTS POSSIBLE.
PREV DISCUSSION... /ISSUED 255 PM CDT MON AUG 17 2015/
SHORT TERM (TONIGHT THROUGH TUESDAY)...
NO MAJOR HIGHLIGHTS THROUGH TUESDAY WITH NEAR NORMAL CONDITIONS
AND LOW END RAIN CHANCES FOR THE COASTAL PLAINS.
WATER VAPOR AND RUC ANALYSIS REVEAL A SHEAR AXIS AND MID TO UPPER
LEVEL LOW ACROSS THE MID MISSISSIPPI VALLEY EXTENDING SOUTHWEST
ALONG THE TEXAS COAST. THIS FEATURE ALONG WITH AFTERNOON
INSTABILITY WILL GOVERN THE WEATHER PATTERN THROUGH
TUESDAY BY KEEPING TEMPERATURES NEAR NORMAL AND ONLY 20-30%
TSTORM CHANCES ALONG THE COAST WHERE THE SEA-BREEZE CONVERGENCE
WILL BE MORE ACTIVE. PRECIPITABLE WATER AMOUNTS CURRENTLY RANGE
FROM 1.0" TO 1.6" FROM THE RIO GRANDE VALLEY TOWARDS THE COASTAL
PLAINS. THESE VALUES ARE ABOUT 0.5 TO 1 STANDARD DEVIATION BELOW
NORMAL AND THUS RESULTING IN LIMITED SHOWER/STORM ACTIVITY ACROSS
A MAJORITY OF THE REGION. THIS PATTERN WILL CONTINUE THROUGH
TOMORROW WITH ONLY LIMITED SHOWERS AND A FEW THUNDERSTORMS ALONG
THE COASTAL PLAINS.
LONG TERM (WEDNESDAY THROUGH MONDAY)...
THE LOW-LEVEL PATTERN WILL CHANGE UP MID TO LATE WEEK AS A
BOUNDARY APPROACHES THE REGION FROM THE NORTH WITH HIGHER RAIN
CHANCES AND LOWER MAX HIGH TEMPERATURES LIKELY.
BY MID-WEEK...GLOBAL MODELS AGREE THAT A LARGE LONG WAVE TROUGH
WILL DEVELOP OVER THE CENTRAL CONUS AND WITH ADDITIONAL SHORTWAVE
TROUGH SUPPORT OVER NEW MEXICO AND TEXAS...A PSEUDO COLD FRONT
WILL APPROACH THE REGION FROM THE NORTH LATE WEDNESDAY INTO
THURSDAY MORNING. WEDNESDAY WILL REMAIN NEAR NORMAL TEMPERATURE
WISE WITH HIGHS STILL IN THE MID TO UPPER 90S AREA WIDE AND LOWER
RAIN CHANCES OF 20-40% AREA WIDE. RAIN CHANCES WILL INCREASE GOING
THROUGH THE OVERNIGHT INTO THURSDAY MORNING FOR THE HILL COUNTRY
AS THE BOUNDARY APPROACHES BUT THEN LOOKS TO STALL. WITH THE
SHEAR AXIS OVER TOP OF THE FRONT...THIS SET-UP SHOULD PROVIDE
AREAS WITH MORE CLOUDS AND WITH PWATS INCREASING TO 1.4" TO
1.8"...MORE WIDESPREAD RAIN CHANCES OF AT LEAST 50% APPEAR A
NOMINAL ROUTE TO GO FOR THURSDAY AND CONTINUING INTO FRIDAY. 12Z
GFS APPEARS TO HAVE A MESOSCALE FEEDBACK ISSUE BY PRODUCING A QPF
BULLSEYE JUST SOUTH OF THE REGION AS IT CONSOLIDATES THE UPPER LOW
INTO A TIGHTER CLOSED LOW. SINCE THIS IS THE FIRST ADVERTISEMENT
OF THIS EVOLUTION...WILL SIDE MORE WITH CONSISTENCY AND THE EC
WHICH ALSO LINGERS THE MID LEVEL ENERGY OVER THE REGION. THE EXTRA
CLOUDS SHOULD RESULT IN MAX HIGHS BEING REDUCED TO LOW TO MID 90S
BEING QUITE PLAUSIBLE.
OVER THE WEEKEND...RAIN CHANCES LOOK TO DECREASE AS THE FRONT
WASHES OUT AND SHIFTS NORTH WITH A SUBTROPICAL RIDGE SLOWLY
INCREASING ITS INFLUENCE ACROSS THE NORTH GULF.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 76 98 77 98 76 / 10 10 10 20 50
AUSTIN BERGSTROM INTL AIRPORT 72 97 74 97 74 / 10 10 10 20 50
NEW BRAUNFELS MUNI AIRPORT 75 98 76 99 76 / 10 10 10 20 40
BURNET MUNI AIRPORT 74 97 75 96 74 / 0 - - 20 50
DEL RIO INTL AIRPORT 76 100 77 100 78 / 0 0 - 20 30
GEORGETOWN MUNI AIRPORT 75 98 77 98 75 / 10 10 10 20 50
HONDO MUNI AIRPORT 73 97 74 98 76 / - - - 20 30
SAN MARCOS MUNI AIRPORT 75 97 77 97 76 / 10 10 10 20 40
LA GRANGE - FAYETTE REGIONAL 75 98 78 98 76 / 20 20 20 30 40
SAN ANTONIO INTL AIRPORT 77 97 78 97 78 / 10 - - 20 40
STINSON MUNI AIRPORT 76 99 77 99 78 / 10 10 10 20 30
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...RUNYEN
SYNOPTIC/GRIDS...26
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
643 PM CDT MON AUG 17 2015
.UPDATE...00Z AVIATION UPDATE BELOW.
&&
.AVIATION...VFR CONDITIONS CONTINUE THROUGH THE EVENING HOURS.
ISOLATED SHRAS WILL END AROUND SUNSET. PATCHES OF MVFR MORNING
STRATUS WERE EVIDENT THIS MORNING...AND COVERAGE SHOULD BE
SLIGHTLY GREATER OVERNIGHT AND TUESDAY MORNING. NAM BUFR SOUNDINGS
COMBINED WITH 950MB MOISTURE PROGS FROM VARIOUS MODELS INDICATE
STRATUS DEVELOPMENT ALONG THE SOUTHERN EDGE OF THE ESCAPRMENT
NEAR SAT AROUND 08Z...POSSIBLY SPREADING INTO AUS TERMINAL 09Z-12Z
AS LOW LEVEL FLOW VEERS SLIGHTLY MORE SW. THERE IS A CHANCE THAT
DRT COULD SEE A PERIOD OF MVFR CEILINGS 13Z-16Z PER NAM BUFR
SOUNDINGS AND HRRR SOLUTIONS...ALTHOUGH CONFIDENCE IS LOWER THAN
I-35 SITES. STRATUS WILL SCATTER OUT QUICKLY LATE MORNING WITH VFR
CONDITIONS AGAIN TUE AFTERNOON. ISOLATED SHRAS AGAIN POSSIBLE TUE
DURING THE MID AFTERNOON AND EVENING HOURS EAST OF I-35. THESE ARE
NOT EXPECTED TO IMPACT THE I-35 TAF SITES. S AND SE FLOW LATE TUE
MORNING AND AFTERNOON WILL BE SLIGHTLY STRONGER...WITH SOME GUSTS
NEAR 20 KTS POSSIBLE.
&&
.PREV DISCUSSION... /ISSUED 255 PM CDT MON AUG 17 2015/
SHORT TERM (TONIGHT THROUGH TUESDAY)...
NO MAJOR HIGHLIGHTS THROUGH TUESDAY WITH NEAR NORMAL CONDITIONS
AND LOW END RAIN CHANCES FOR THE COASTAL PLAINS.
WATER VAPOR AND RUC ANALYSIS REVEAL A SHEAR AXIS AND MID TO UPPER
LEVEL LOW ACROSS THE MID MISSISSIPPI VALLEY EXTENDING SOUTHWEST
ALONG THE TEXAS COAST. THIS FEATURE ALONG WITH AFTERNOON
INSTABILITY WILL GOVERN THE WEATHER PATTERN THROUGH
TUESDAY BY KEEPING TEMPERATURES NEAR NORMAL AND ONLY 20-30%
TSTORM CHANCES ALONG THE COAST WHERE THE SEA-BREEZE CONVERGENCE
WILL BE MORE ACTIVE. PRECIPITABLE WATER AMOUNTS CURRENTLY RANGE
FROM 1.0" TO 1.6" FROM THE RIO GRANDE VALLEY TOWARDS THE COASTAL
PLAINS. THESE VALUES ARE ABOUT 0.5 TO 1 STANDARD DEVIATION BELOW
NORMAL AND THUS RESULTING IN LIMITED SHOWER/STORM ACTIVITY ACROSS
A MAJORITY OF THE REGION. THIS PATTERN WILL CONTINUE THROUGH
TOMORROW WITH ONLY LIMITED SHOWERS AND A FEW THUNDERSTORMS ALONG
THE COASTAL PLAINS.
LONG TERM (WEDNESDAY THROUGH MONDAY)...
THE LOW-LEVEL PATTERN WILL CHANGE UP MID TO LATE WEEK AS A
BOUNDARY APPROACHES THE REGION FROM THE NORTH WITH HIGHER RAIN
CHANCES AND LOWER MAX HIGH TEMPERATURES LIKELY.
BY MID-WEEK...GLOBAL MODELS AGREE THAT A LARGE LONG WAVE TROUGH
WILL DEVELOP OVER THE CENTRAL CONUS AND WITH ADDITIONAL SHORTWAVE
TROUGH SUPPORT OVER NEW MEXICO AND TEXAS...A PSEUDO COLD FRONT
WILL APPROACH THE REGION FROM THE NORTH LATE WEDNESDAY INTO
THURSDAY MORNING. WEDNESDAY WILL REMAIN NEAR NORMAL TEMPERATURE
WISE WITH HIGHS STILL IN THE MID TO UPPER 90S AREA WIDE AND LOWER
RAIN CHANCES OF 20-40% AREA WIDE. RAIN CHANCES WILL INCREASE GOING
THROUGH THE OVERNIGHT INTO THURSDAY MORNING FOR THE HILL COUNTRY
AS THE BOUNDARY APPROACHES BUT THEN LOOKS TO STALL. WITH THE
SHEAR AXIS OVER TOP OF THE FRONT...THIS SET-UP SHOULD PROVIDE
AREAS WITH MORE CLOUDS AND WITH PWATS INCREASING TO 1.4" TO
1.8"...MORE WIDESPREAD RAIN CHANCES OF AT LEAST 50% APPEAR A
NOMINAL ROUTE TO GO FOR THURSDAY AND CONTINUING INTO FRIDAY. 12Z
GFS APPEARS TO HAVE A MESOSCALE FEEDBACK ISSUE BY PRODUCING A QPF
BULLSEYE JUST SOUTH OF THE REGION AS IT CONSOLIDATES THE UPPER LOW
INTO A TIGHTER CLOSED LOW. SINCE THIS IS THE FIRST ADVERTISEMENT
OF THIS EVOLUTION...WILL SIDE MORE WITH CONSISTANCY AND THE EC
WHICH ALSO LINGERS THE MID LEVEL ENERGY OVER THE REGION. THE EXTRA
CLOUDS SHOULD RESULT IN MAX HIGHS BEING REDUCED TO LOW TO MID 90S
BEING QUITE PLAUSIBLE.
OVER THE WEEKEND...RAIN CHANCES LOOK TO DECREASE AS THE FRONT
WASHES OUT AND SHIFTS NORTH WITH A SUBTROPICAL RIDGE SLOWLY
INCREASING ITS INFLUENCE ACROSS THE NORTH GULF.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 76 98 77 98 76 / 10 10 10 20 50
AUSTIN BERGSTROM INTL AIRPORT 72 97 74 97 74 / 10 10 10 20 50
NEW BRAUNFELS MUNI AIRPORT 75 98 76 99 76 / 10 10 10 20 40
BURNET MUNI AIRPORT 74 97 75 96 74 / 0 - - 20 50
DEL RIO INTL AIRPORT 76 100 77 100 78 / 0 0 - 20 30
GEORGETOWN MUNI AIRPORT 75 98 77 98 75 / 10 10 10 20 50
HONDO MUNI AIRPORT 73 97 74 98 76 / - - - 20 30
SAN MARCOS MUNI AIRPORT 75 97 77 97 76 / 10 10 10 20 40
LA GRANGE - FAYETTE REGIONAL 75 98 78 98 76 / 20 20 20 30 40
SAN ANTONIO INTL AIRPORT 77 97 78 97 78 / 10 - - 20 40
STINSON MUNI AIRPORT 76 99 77 99 78 / 10 10 10 20 30
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...RUNYEN
SYNOPTIC/GRIDS...26
PUBLIC SERVICE/DATA COLLECTION...LH
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1208 PM CDT SUN AUG 16 2015
.AVIATION...
/18Z TAFS/
Isolated showers and thunderstorms may affect KSJT and KSOA this
afternoon. However, confidence in timing/location preclude any
thunder mention in the TAFs. Near KSJT, a large wildfire was
located 13 SM south of the terminal. Smoke from this may affect
KSJT at times, especially at night and during the morning.
Carrying smoke in present weather with a few clouds at 100 feet
during that time period to account for this. Otherwise, VFR
conditions will prevail.
&&
.PREV DISCUSSION... /ISSUED 941 AM CDT SUN AUG 16 2015/
UPDATE...
Forecast has been updated to include possibility of isolated
showers and thunderstorms this afternoon and evening, across
the area roughly southwest of a line from Anson to Coleman to
San Saba. Water loop shows drier air in the mid/upper levels
impinging on our eastern counties. If this drier air does not
overspread our area and remains confined to our eastern counties,
the possibility of isolated shower/thunderstorm development cannot
be ruled out. The HRRR and NAM12 support this possibility. Have
updated sky condition grids for slightly increased cloud cover.
Will continue to monitor and update the forecast as needed today.
PREV DISCUSSION... /ISSUED 604 AM CDT SUN AUG 16 2015/
AVIATION...
/12Z TAFS/
VFR conditions with light winds will continue at all terminals
through the next 24 hours.
PREV DISCUSSION... /ISSUED 310 AM CDT SUN AUG 16 2015/
SHORT TERM...
(Today and Tonight)
A broad upper level high will be centered over the Desert Southwest
today and will move further west over the northern Baja. Through
tonight, the forecast area will be situated between the upper high
to our west and an inverted upper trough stretching from the Texas
Gulf coast northeast over the lower Mississippi Valley to our east.
The flow aloft will therefore remain north-northeasterly with drier
air advecting into the area. As a result, chances of any
shower/thunderstorm development will be remote. Afternoon highs will
be in the mid to upper 90s with morning lows tomorrow in the lower
70s.
15
LONG TERM...
(Monday-Saturday)
West Central Texas will remain on the eastern side of a ridge of
high pressure, centered over southern California and northern Baja,
through Monday evening. Both the GFS and ECMWF prog a strong shortwave
trough/80-90kt polar jet max to dive southeast into the Central
Plains Tuesday into Wednesday, allowing a cold front to slide
south into the region on Wednesday.
The 00Z ECMWF and GFS were similar. For now, am splitting the
difference between the models. This upper trough and front should
give the eastern sections of WC TX the best chance for rain and
thunderstorms Wednesday afternoon and night. Cooler temperatures
are on tap for Wednesday and Thursday for much of the area. Still
too much uncertainty to pin point exact locations for rain.
Precipitable water values are progged to be in excess of 1.5
inches just ahead of the front with good low level convergence at
850 MB.
After the front moves across the area Wednesday and Wednesday
night, an upper level high pressure system is progged to build
into the area by the latter part of the week, causing temperatures
to rebound into the mid and upper 90s.
26
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 97 73 95 74 / 5 5 0 0
San Angelo 98 72 96 73 / 10 10 0 0
Junction 97 71 94 72 / 10 10 5 0
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Aviation: Doll
AREA FORECAST DISCUSSION...UPDATED
NWS SAN ANGELO TX
941 AM CDT SUN AUG 16 2015
.UPDATE...
Forecast has been updated to include possibility of isolated
showers and thunderstorms this afternoon and evening, across
the area roughly southwest of a line from Anson to Coleman to
San Saba. Water loop shows drier air in the mid/upper levels
impinging on our eastern counties. If this drier air does not
overspread our area and remains confined to our eastern counties,
the possibility of isolated shower/thunderstorm development cannot
be ruled out. The HRRR and NAM12 support this possibility. Have
updated sky condition grids for slightly increased cloud cover.
Will continue to monitor and update the forecast as needed today.
&&
.PREV DISCUSSION... /ISSUED 604 AM CDT SUN AUG 16 2015/
AVIATION...
/12Z TAFS/
VFR conditions with light winds will continue at all terminals
through the next 24 hours.
PREV DISCUSSION... /ISSUED 310 AM CDT SUN AUG 16 2015/
SHORT TERM...
(Today and Tonight)
A broad upper level high will be centered over the Desert Southwest
today and will move further west over the northern Baja. Through
tonight, the forecast area will be situated between the upper high
to our west and an inverted upper trough stretching from the Texas
Gulf coast northeast over the lower Mississippi Valley to our east.
The flow aloft will therefore remain north-northeasterly with drier
air advecting into the area. As a result, chances of any
shower/thunderstorm development will be remote. Afternoon highs will
be in the mid to upper 90s with morning lows tomorrow in the lower
70s.
15
LONG TERM...
(Monday-Saturday)
West Central Texas will remain on the eastern side of a ridge of
high pressure, centered over southern California and northern Baja,
through Monday evening. Both the GFS and ECMWF prog a strong shortwave
trough/80-90kt polar jet max to dive southeast into the Central
Plains Tuesday into Wednesday, allowing a cold front to slide
south into the region on Wednesday.
The 00Z ECMWF and GFS were similar. For now, am splitting the
difference between the models. This upper trough and front should
give the eastern sections of WC TX the best chance for rain and
thunderstorms Wednesday afternoon and night. Cooler temperatures
are on tap for Wednesday and Thursday for much of the area. Still
too much uncertainty to pin point exact locations for rain.
Precipitable water values are progged to be in excess of 1.5
inches just ahead of the front with good low level convergence at
850 MB.
After the front moves across the area Wednesday and Wednesday
night, an upper level high pressure system is progged to build
into the area by the latter part of the week, causing temperatures
to rebound into the mid and upper 90s.
26
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 97 73 95 75 / 5 5 0 0
San Angelo 98 72 96 73 / 10 10 0 0
Junction 97 71 94 72 / 10 10 5 0
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
844 PM EDT MON AUG 17 2015
.SYNOPSIS...
WEAK HIGH PRESSURE ACROSS THE REGION TONIGHT WILL WEAKEN AND
SLIDE EAST TO OFFSHORE THE MID ATLANTIC COAST ON TUESDAY. A COLD
FRONT IS EXPECTED TO DRIFT SOUTHEAST TOWARD THE REGION WEDNESDAY
INTO THURSDAY BEFORE CROSSING INTO THE AREA THURSDAY NIGHT. THIS
WILL RESULT IN MULTIPLE PERIODS OF SHOWERS AND STORMS THROUGH
THURSDAY BEFORE DRIER AIR WORKS IN BEHIND THE PASSING FRONT ON
FRIDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 825 PM EDT MONDAY...
EVENING SOUNDINGS SHOW QUITE A BIT OF MOISTURE AND INSTABILITY
HAVING MADE A RETURN TO THE REGION TONIGHT WITH DEEPER SOUTHERLY
FLOW AND PWATS NEAR 1.5 INCHES. HOWEVER FAINT CAP ALOFT ALONG WITH
MOST LIFT BEING WEST OF THE MOUNTAINS WITH THE UPSTREAM
IMPULSE...HAS KEPT MOST ORGANIZED CONVECTION CONFINED TO THE FAR
WEST ON THE LEADING EDGE OF THE PRECIP SHIELD AND WITH RESIDUAL
OUTFLOW. LATEST ANALYSIS SHOWING A DECENT AMOUNT OF LEFTOVER INSTABILITY
ESPCLY BLUE RIDGE EAST SO TRICKY IN REGARDS TO WHETHER OR NOT COVERAGE
WILL FILL IN OVER THE NEXT FEW HOURS DESPITE LOSS OF HEATING.
LATEST HRRR REMAINS QUITE WET IN DEVELOPING SHRA/TSRA ACROSS MUCH
OF THE WEST OUT TO THE BLUE RIDGE BY MIDNIGHT WITH SOME OF THIS
COVERAGE HEADING EAST INTO THE PIEDMONT BEFORE DAYBREAK. THIS
LOOKS A BIT OVERDONE BUT GIVEN COVERAGE DEVELOPING ACROSS THE SW
AND LESS WORKED OVER NATURE TO THINGS FROM THIS AFTERNOON WILL
SPEED UP LIKELY POPS WEST AND EDGE HIGHER CHANCES EAST OVERNIGHT.
TEMPS TO REMAIN MUCH MORE ON THE WARM/MUGGY SIDE OVERNIGHT GIVEN
THE INCREASE IN MOISTURE...AND EXPECT SOME EASTERN LOCATIONS TO
STAY ABOVE 70 SO BUMPING UP LOWS A FEW DEGREES OVERALL.
PREVIOUS DISCUSSION AS OF 235 PM EDT MONDAY...
STICKING CLOSER TO THE LOCAL WRF/HRRR THIS AFTERNOON INTO THE
EVENING WITH SCATTERED SHOWER AND STORM COVERAGE FROM THE BLUE
RIDGE WEST. COVERAGE AT THE MOMENT IS WIDELY SCATTERED WITH BEST
INSTABILITY SITUATED OVER THE NC/VA FOOTHILLS...WHERE SOME CELLS
HAD DEVELOPED INTO THUNDERSTORMS. MEAN FLOW WILL STAY WEAK SO
HEAVY RAINERS WILL OCCUR.
THIS ACTIVITY DIMINISHES SOMEWHAT THIS EVENING WITH LOSS OF
HEATING...BUT OVERNIGHT THE SHORTWAVE FROM SOUTHERN ILLINOIS TO MID
TENNESSEE WILL WORK NORTHEAST ACROSS THE MOUNTAINS INCREASING LIFT
AND WITH HIGHER PWATS...SHOULD SEE AN AREA OF SHOWERS...MAYBE A
RUMBLE OF THUNDER TRACK INTO THE MOUNTAINS. HAVE LIKELY TO SOME
CATEGORICAL POPS MAINLY WEST OF A COVINGTON VA TO MOUNT AIRY NC
LINE...WITH QUICKLY DIMINISHING POPS TO SLIGHT CHANCE EAST OF
LYNCHBURG/DANVILLE UNDERNEATH THE SFC HIGH.
THE FLOW WILL INCREASE AT 8H SO SHOWERS SHOULD BE MOVING A LITTLE
FASTER THAN THIS AFTERNOON. WITH PLENTY OF CLOUDS LOW TEMPS WILL BE
ELEVATED IN THE MID 60S TO AROUND 70.
TUESDAY...SHORTWAVE LIFTS NORTHEAST...BUT THERE IS SOME WEAK
UPPER SUPPORT AND DIFFLUENCE REMAINING TO KEEP LIKELY POPS GOING
ACROSS MOST OF THE FORECAST AREA. STORM CHANCE WILL BE LIMITED BY
CLOUD COVER BUT THINK THE UPPER SUPPORT IS ENOUGH TO HAVE THUNDER
INTO THE REGION BY AFTERNOON. HIGHS WILL BE TEMPERED BY CLOUD
COVER BUT WILL BE HUMID. TEMPS WILL RUN FROM THE LOWER TO MID 70S
OVER THE HIGHER ELEVATIONS AND ADJACENT VALLEYS IN THE WEST...WITH
UPPER 70S TO LOWER 80S ACROSS THE FOOTHILLS AND PIEDMONT INCLUDING
THE ROANOKE VALLEY.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
AS OF 230 PM EDT MONDAY...
THE CWA WILL BE EXPOSED TO SOUTHERLY FLOW FROM THE COMBINATION OF
HIGH PRESSURE OFFSHORE...AND AN APPROACHING COLD FRONT IN THE PLAINS
DURING TUESDAY NIGHT INTO WEDNESDAY. SOME CONVECTIVE ACTIVITY MAY
NOT FADE OUT SO QUICKLY IN THE NIGHTTIME HOURS DUE TO INCREASING
INSTABILITY AND MOISTURE AHEAD OF THE FRONT. AS A RESULT...MOST OF
THIS FORECAST PERIOD WILL BE EMBEDDED IN CHANCES OF SHOWERS AND
THUNDERSTORMS...WITH SOME DIURNAL VARIATION IN THE THUNDERSTORM
COVERAGE. DURING WEDNESDAY AFTERNOON AND EVENING...POPS WERE KEPT
HIGHEST MAINLY WEST OF THE BLUE RIDGE.
AS THE COLD FRONT DRAWS NEARER ON THURSDAY...LOOK FOR COVERAGE AND
ACTIVITY OF THE SHOWERS AND THUNDERSTORMS TO INCREASE MORE
SIGNIFICANTLY...ESPECIALLY WEST OF THE BLUE RIDGE. BOTH THE 12Z
ECMWF AND GFS MODELS SHOW THE EXPECTED FRONTAL PASSAGE AROUND
THURSDAY EVENING. ALTHOUGH SEVERE WEATHER THREAT PROJECTIONS APPEAR
LOW FROM SPC...THERE WILL BE A THREAT OF HEAVY RAIN HITTING THE SAME
LOCATIONS REPEATEDLY ON WEDNESDAY AND THURSDAY...WHICH COULD INDUCE
LOCALIZED FLOODING. AFTER THE FRONT CLEARS THE CWA BY EARLY FRIDAY
MORNING...CLOUD COVER AND POPS WILL GRADUALLY LESSEN.
TEMPERATURES DO NOT SHOW MUCH APPRECIABLE CHANGE BEFORE THE COLD
FRONT ARRIVES. THE AIR MASS WILL BECOME INCREASINGLY HUMID ON
WEDNESDAY AND THURSDAY...WHERE LOW TEMPERATURES MAY FAIL TO DROP
BELOW THE MID 60S IN THE MOUNTAINS...AND THE UPPER 60S TO THE LOWER
70S IN THE PIEDMONT. HIGHS SHOULD VARY FROM THE UPPER 70S TO THE
UPPER 80S...WHICH IS WELL IN AGREEMENT WITH THE MOS GUIDANCE. LOWS
ON FRIDAY MORNING WILL BE A LITTLE COOLER THANKS TO THE FRONTAL
PASSAGE...AS TEMPERATURES MAY HIT 60 DEGREES OR LOWER IN THE HIGHER
ELEVATIONS.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 218 PM EDT MONDAY...
LOW CONFIDENCE FORECAST DURING THE PERIOD AS MODELS ARE AGGRESSIVELY
PUSHING A COLD FRONT SOUTH INTO THE CAROLINAS ON FRIDAY. THERE ARE
SEVERAL REASONS REGARDING OUR LOW CONFIDENCE. ONE BIG FACTOR IS THE
TIME OF YEAR. MODELS TEND TO PUSH FRONTS TOO FAR SOUTH DURING
AUG-OCT TIME FRAME. ANOTHER DEALS WITH A WEAK SURFACE HIGH
PRESSURE BEHIND THE FRONT AND A STRONG UPPER LEVEL RIDGE ACROSS
THE GULF STATES. THE SURFACE FRONT COULD PUSH SOUTH INTO CENTRAL
NORTH CAROLINA...HOWEVER MID AND UPPER LEVEL MOISTURE WILL KEEP
CLOUDS AND THE CHANCE FOR RAIN IN THE AREA ONGOING INTO THE
WEEKEND. SINCE THIS IS A WEAK SURFACE HIGH/WEDGE...BOUNDARY LIKELY
TO RETREAT NORTH...KEEPING THE CHANCES FOR SHOWERS IN THE AREA
THROUGH THE WEEKEND. THE THREAT FOR SHOWERS AND THUNDERSTORMS
INCREASES MONDAY AS A STRONG COLD FRONT APPROACHES FROM THE WEST.
ALONG WITH THE LOW CONFIDENCE FORECAST...WE WILL KEEP TEMPERATURES
CLOSE TO SEASONAL LEVELS THROUGH THE PERIOD. THE COOLEST OF MAY BE
SATURDAY AND THE WARMEST MONDAY.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 645 PM EDT MONDAY...
CONVECTION REMAINS QUITE ISOLATED THIS EVENING WITH MORE
WIDESPREAD SHOWERS TO THE NORTH AND WEST OF KBLF/KLWB ATTM. THUS
WILL CONTINUE TO COVER ANY POTENTIAL FOR AN ISOLATED SHRA/TSRA TO
AFFECT ANY TAF SITE WITH A VCSH/VCTS OVER THE NEXT FEW HOURS.
MORE SHOWERS AND THUNDERSTORMS WILL MOVE INTO THE REGION OVERNIGHT FROM
THE WEST ASSOCIATED WITH DEEPER MOISTURE ADVECTION AND WEAK ENERGY
SLIDING ACROSS. MODELS REMAIN DIFFERENT WITH TIMING OF THE
ASSOCIATED SHOWERS INTO THE AREA WITH SPREAD FROM LATE THIS
EVENING PER THE LOCAL WRF...TO NOT UNTIL MORNING ALONG THE BLUE
RIDGE. GIVEN CURRENT TRENDS HAVE OPTED TO SPEED UP SHOWERS A BIT
AND BRING MVFR CONDITIONS INTO THE WESTERN SITES JUST AFTER
MIDNIGHT WHILE KEEPING KDAN/KLYH DRY.
PERIODIC ROUNDS OF SHOWERS WITH ISOLATED ELEVATED THUNDER LIKELY
TUESDAY AS RIPPLES OF ENERGY TRAVERSE THE REGION WITHIN AN AXIS OF
TROPICAL TYPE PWATS. HOWEVER GUIDANCE STILL NOT TOTALLY ON BOARD
WITH A PROLONGED PERIOD OF MVFR/IFR CIGS AND MVFR VSBYS ESPCLY
EAST GIVEN DIFFERENCES IN HANDLING OF THE WEAK WAVES TO THE SW.
SINCE SOME UNCERTAINTY IN COVERAGE STILL EXISTS...WILL HOLD OFF ON
LOWERING CIGS AS LOW AS MOST MODELS WHILE KEEPING IN MOSTLY
MVFR/IFR CIGS AND MVFR VSBYS IN BANDS OF SHOWERS INTO TUESDAY
AFTERNOON. BETTER INSTABILITY REMAINS PROGGED TO THE SOUTH AND
WEST SO NOT INCLUDING ANY TSRA MENTION DESPITE PREVAILING LOWER
CONDITIONS FOR MOST SPOTS DURING THE DAY.
EXPECT SHOWERS TO TAPER OFF TUESDAY NIGHT AS UPPER SUPPORT EXITS
AND THE REGION MOVES INTO A LULL BETWEEN THE PASSING IMPULSES AND
THE UPSTREAM COLD FRONT. LINGERING MOISTURE SHOULD MAKE FOR
WIDESPREAD SUB-VFR IN THE WAKE OF THE SHOWERS WITH LOTS OF STRATUS
AND FOG AROUND UNTIL LATE TUESDAY NIGHT.
EXTENDED AVIATION DISCUSSION...
WEDNESDAY THROUGH THURSDAY....SHOWERS AND
THUNDERSTORMS...INCLUDING SUB-VFR CONDITIONS...WILL BE MORE
SCATTERED TO NUMEROUS THANKS TO A SLOW MOVING FRONTAL BOUNDARY
THAT WILL STALL JUST NORTHWEST OF THE REGION. THIS BOUNDARY WILL
ACT AS THE FOCUSING MECHANISM FOR MULTIPLE ROUNDS OF SHOWERS AND
THUNDERSTORMS ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS
FOLLOWED BY PATCHY FOG DURING THE OVERNIGHTS.
WE WILL START TO DRY OUT SOME GOING INTO FRIDAY AS THE FRONT MOVES
SOUTHEAST...BUT SOME LINGERING ACTIVITY POSSIBLE OVER THE KDAN TO
KTNB CORRIDOR. SHOULD RETURN TO OVERALL VFR SATURDAY WITH THE
FRONT OFFSHORE AND WEAK HIGH PRESSURE ABOUT OVERHEAD THE MOUNTAINS
FOR MUCH OF THE DAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...JH/WP
SHORT TERM...PW
LONG TERM...RCS
AVIATION...AMS/JH/WP
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
847 PM CDT MON AUG 17 2015
.UPDATE...SPC MESO ANALYSIS CONTINUES TO SHOW SOME MLCAPE
LINGERING ACROSS THE CWA ESP ACROSS SC/SW SECTIONS OF THE CWA.
SOME LOW LEVEL CONVERGENCE TIED TO SFC TROUGH/FRONTAL BOUNDARY
EXTENDING FROM NEAR KMTW SWWD INTO NE IA. IN ADDITION COMBO OF
UPSTREAM SHORTWAVE AND RIGHT REAR QUAD JET/DIFFLUENT FLOW REGIME
AIDING VERTICAL MOTION FIELD. SO THERE IS SOME SUPPORT FOR
ADDITIONAL DYNAMIC OOMPH FOR THESE CELLS POPPING UP ACROSS THE
AREA...PLUS THERE IS ANOTHER BATCH OF SHRA/ISOLD TSRA UPSTREAM IN
SRN MN/NRN IA. SO WILL KEEP THE POPS GOING FOR THE NIGHT.
PC
&&
.AVIATION/06Z TAFS/...MAIN CONCERN IS IN STRATUS DEVELOPMENT AND
FOG POTENTIAL AS THE NIGHT WEARS ON. WILL CONTINUE WITH SOME LWR
VSBYS/CIGS DUE TO LIGHT WIND REGIME. HOWEVER EXISTING CLOUD COVER
WILL NEGATE THINGS FROM RADIATION OUT AND REALLY GETTING TOO
WIDESPREAD OR DENSE. SREF CIG/VSBY PROGS SHOW BETTER POTENTIAL IN
MW CWA CLOSER TO TROUGH AXIS. SHRA/ISOLD TSRA LIKELY TO PERSIST
THROUGH THE NIGHT DUE TO SOME LINGERING INSTAB AND UPSTREAM
SHORTWAVE ACTIVITY AND JET STREAM DYNAMICS APPCHG. BOUNDARY
COMBINED WITH MORE VIGOROUS DYNAMICS ON TUE AFTN/NGT LIKELY TO
GENERATE MORE SHRA/TSRA
PC
&&
.PREV DISCUSSION... /ISSUED 335 PM CDT MON AUG 17 2015/
SHORT TERM...
LATE THIS AFTERNOON AND EARLY EVENING...FORECAST CONFIDENCE IS
MEDIUM.
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS CURRENTLY ARE
SHIFTING SLOWLY NORTHEASTWARD ACROSS THE AREA...ALONG AND AHEAD OF A
WEAK COLD FRONT. THE PRECIPITATION WAS BEING FED BY UPPER DIVERGENCE
FROM A RIGHT REAR ENTRANCE REGION OF A 250 MB JET STREAK. THERE WAS
ALSO SOME 700 MB MOISTURE AND CYCLONIC VORTICITY ADVECTION IN THIS
AREA.
THE UPPER DIVERGENCE IS EXPECTED TO SHIFT EASTWARD ACROSS THE AREA
LATE THIS AFTERNOON INTO EARLY EVENING...AS THE SURFACE COLD FRONT
SLOWLY STALLS ACROSS OR JUST SOUTH OF THE AREA. BEST MESOSCALE
MODELS HAVE BEEN THE HRRR AND EXPERIMENTAL HRRR MODELS...WHICH HAVE
BEEN SLOW THEMSELVES TO INITIATE THE CURRENT CONVECTION. THEY HAVE
THIS ACTIVITY SLIDING OFF TO THE EAST OF THE AREA BY EARLY THIS
EVENING. FOLLOWED THIS TREND WITH THE HIGH END POPS INTO EARLY
EVENING.
SMALL HAIL AND GUSTY WINDS TO AROUND 40 MPH ARE MAINLY EXPECTED WITH
THE STRONGER STORMS...AS DEEP LAYER SHEAR AND MID LEVEL LAPSE RATES
REMAIN RATHER WEAK. AN ISOLATED SEVERE STORM IS POSSIBLE...GIVEN
DECENT 0 TO 3 KM AND MEAN LAYER CAPES ACROSS THE AREA.
REST OF TONIGHT INTO TUESDAY...FORECAST CONFIDENCE IS MEDIUM.
MORE UNCERTAINTY WITH REGARDS TO POPS FOR LATER THIS EVENING INTO
TUESDAY MORNING. FRONTAL BOUNDARY SHOULD STALL ACROSS OR JUST SOUTH
OF THE AREA. 500 MB VORTICITY MAXIMUM DOES SHIFT THROUGH THE AREA
LATER TONIGHT...WHICH MAY BRING SOME UPWARD MOTION. THE MESOSCALE
MODELS TRY TO BRING IN SOME SHOWERS/STORMS FROM THE SOUTHWEST WITH
THIS FEATURE. KEPT CHANCE POPS FOR COLLABORATION SAKE FOR NOW...BUT
IT MAY END UP DRIER THAN FORECAST.
SHOULD SEE FOG AND SOME LOW STRATUS DEVELOP ACROSS THE AREA LATER
THIS EVENING INTO TUESDAY MORNING...WITH LIGHT WINDS AND MOIST LOW
LEVELS. DENSE FOG IS NOT ANTICIPATED...THOUGH COULD SEE IT IN LOW
LYING AREAS AS WINDS ABOVE THE WEAK INVERSION WEAKEN. THIS WILL HAVE
TO BE WATCHED BY LATER SHIFTS.
BETTER POPS RETURN TUESDAY AFTERNOON...AS FRONT BEGINS TO MOVE
NORTHWARD AS A WARM FRONT. ANOTHER 500 MB VORTICITY MAXIMUM
APPROACHES THE AREA LATER IN THE DAY...ALONG WITH AN INCREASING LOW
LEVEL JET. DEEP LAYER SHEAR REMAINS WEAK IN THE AFTERNOON...WITH
MODEST MEAN LAYER CAPES. SO...THINK SEVERE RISK IS MINIMAL IN THE
AFTERNOON PERIOD.
TUESDAY NIGHT AND WEDNESDAY...FORECAST CONFIDENCE...MEDIUM
THE GFS MOVES THE STRONG MID/UPPER TROUGH INTO THE UPPER
MISSISSIPPI VALLEY WEDNESDAY. THE UPPER FLOW IS DIFFLUENT TUESDAY
NIGHT AHEAD OF THE TROUGH AND APPROACHING JET. AS THE 250 MB
UPPER JET ROUNDS THE BASE OF THE TROUGH AND LIFTS ACROSS WISCONSIN
IT INCREASES TO 115 KNOTS. THE UPPER DIVERGENCE AND 700 MB UPWARD
MOTION IS STRONGEST TUESDAY NIGHT...BUT WEAKER UPWARD MOTION
CONTINUES INTO THE EARLY AFTERNOON OVER SOUTHEAST WISCONSIN. 700
MB LEVELS ARE NEAR SATURATION TUESDAY NIGHT WITH THE MID LEVEL
DRYING WEDNESDAY MORNING. THE FAR SOUTHEAST IS STILL NEAR THE 700
MB MOISTURE INTO THE AFTERNOON. A 40 KNOT 700 MB SPEED MAX PUSHES
INTO THE SOUTHWEST TUESDAY NIGHT...WITH THE 55 KNOT CORE OVER
SOUTHERN WISCONSIN AROUND NOON WEDNESDAY.
THE 850 MB THERMAL RIDGE IS INTO SOUTHERN WISCONSIN LATE TUESDAY
NIGHT AND REMAINS NEAR KENOSHA WEDNESDAY AFTERNOON. COLD AIR
ADVECTION OCCURS OVER SOUTH CENTRAL WISCONSIN WEDNESDAY
MORNING...AND ACROSS THE SOUTHEAST BY NOON. THE RIBBON OF 850 MB
MOISTURE IS ACROSS MOST OF THE FORECAST AREA BY SUNRISE WEDNESDAY
WITH DRYING FROM THE WEST REACHING LAKE MICHIGAN BY NOON.
SHOWERS AND THUNDERSTORMS OCCUR OVER MUCH OF THE AREA TUESDAY
NIGHT AND BECOMES MORE OF A LINE AS THEY STRENGTHEN AGAIN OVER
SOUTHEAST WISCONSIN WEDNESDAY MORNING. BY WEDNESDAY AFTERNOON THE
PRECIPITATION IF ALL TO THE NORTH AND EAST AS THE MID AND THEN LOW
LEVEL DRYING TAKES OVER.
ZERO TO 1 KM CAPE IS AROUND 500 JOULES/KG TUESDAY NIGHT AND NEAR
800 JOULES/KG OVER THE FAR EAST BY MID MORNING. TIMING FOR THE
SEVERE POTENTIAL IS POOR...BUT SOME SEVERE POTENTIAL IS THERE
TUESDAY NIGHT. THE MODELS HAVE TRENDED A LITTLE SLOWER...AND ANY
MORE DELAY WOULD INCREASE THE RISK...OVER THE EAST ON WEDNESDAY.
WEDNESDAY NIGHT AND THURSDAY...FORECAST CONFIDENCE...MEDIUM
THE GFS BRINGS A CLOSED MID/UPPER LOW NEAR DULUTH WEDNESDAY NIGHT
BEFORE LIFTING INTO SOUTHERN CANADA THURSDAY. BOTH THE 12Z NAM AND
00Z ECMWF IS A LITTLE QUICKER...AND NOT AS STRONG WITH THE LOW.
THE 850/700 MB RH INCREASES OVER SOUTH CENTRAL WISCONSIN EARLY
WEDNESDAY EVENING...AND OVER MUCH OF THE SOUTH WEDNESDAY NIGHT
WITH THE EDGE OF THE HIGHER RH NEAR THE ILLINOIS BORDER AREA.
THE WRAP AROUND PRECIPITATION STAYS NORTHWEST OF THE FORECAST
AREA...BUT THE GFS DOES BRUSH NORTHWEST SAUK COUNTY BRIEFLY
WEDNESDAY NIGHT.
THE 850/700 MB RH LIFTS NORTH DURING THE DAY THURSDAY. WEST
WINDS WILL BE BRISK.
LONG TERM...
THURSDAY NIGHT AND FRIDAY...FORECAST CONFIDENCE...MEDIUM
A ZONAL FLOW AGAIN BRIEFLY DEVELOPS IN THE MID/UPPER LEVELS
ACROSS WISCONSIN WITH ANOTHER SHORTWAVE MOVING TOWARD THE NORTHERN
ROCKIES FRIDAY. THE GFS IS A LITTLE SLOWER WITH THIS.
BOTH THE GFS AND ECMWF ARE MAINLY DRY.
FRIDAY NIGHT AND SATURDAY...FORECAST CONFIDENCE...MEDIUM
THE MID/UPPER TROUGH EXITS THE NORTHERN ROCKIES AND MOVES INTO THE
NORTHERN PLAINS WITH A WEAK RIDGE OVER WISCONSIN.
BOTH THE 12Z GFS AND 00Z ECMWF KEEP A LOW OVER THE PLAINS WITH
SOME PRECIPITATION JUST APPROACHING THE FORECAST AREA.
SUNDAY...FORECAST CONFIDENCE...MEDIUM
THE SHORTWAVE REACHES THE UPPER MISSISSIPPI VALLEY SUNDAY. THE
GFS IS JUST A LITTLE FARTHER NORTH AND SLOWER WITH THE SHORTWAVE.
THE SURFACE TROUGH MOVES INTO THE UPPER GREAT LAKES ALONG WITH A
BAND OF MODERATE PRECIPITATION WITH A TRAILING COLD FRONT.
MONDAY...FORECAST CONFIDENCE...MEDIUM
THE SHORTWAVE MOVES ACROSS THE UPPER GREAT LAKES.
THE 00Z ECMWF HAS SOME LIGHT PRECIPITATION WITH THE LINGERING
UPPER LOW...MAINLY NORTH AREAS...WHILE THE GFS IS DRY ON MONDAY AS
HIGH PRESSURE APPROACHES FROM THE PLAINS.
AVIATION/00Z TAFS/...
A WEAK COLD FRONT WILL STALL AROUND OR JUST SOUTH OF THE AREA LATE
THIS AFTERNOON AND TONIGHT. SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS ARE EXPECTED INTO THE EARLY EVENING HOURS...BEFORE
SHIFTING OFF TO THE EAST. SMALL HAIL AND GUSTS TO 40 MPH ARE
EXPECTED WITH THE STRONGER STORMS...WITH MVFR VISIBILITIES.
ENOUGH LOW LEVEL MOISTURE AND LIGHT WINDS LATER TONIGHT INTO TUESDAY
MORNING SHOULD LEAD TO IFR FOG AND SOME LOW STRATUS DEVELOPMENT
ACROSS THE AREA. KEPT THIS MENTION GOING IN TAFS.
FRONT MOVES NORTHWARD THROUGH AREA TUESDAY AS A WARM FRONT...WHICH
WILL BRING MORE CHANCES FOR SHOWERS AND STORMS. BEST CHANCES WILL BE
LATER IN THE DAY. WILL MENTION VICINITY THUNDER IN TAFS...GIVEN SOME
TIMING/AREAL COVERAGE UNCERTAINTY. SOUTHEAST WINDS SHOULD INCREASE
DURING THE DAY TUESDAY.
MARINE...
SCATTERED/NUMEROUS SHOWERS/STORMS ARE EXPECTED TO AFFECT THE
NEARSHORE WATERS OF LAKE MICHIGAN INTO THE EARLY EVENING HOURS...AS
A WEAK COLD FRONT MOVES INTO THE AREA. SMALL HAIL AND GUSTY WINDS TO
33 KNOTS ARE POSSIBLE IN THE STRONGER STORMS.
SHOULD SEE FOG DEVELOP ACROSS THE NEARSHORE WATERS OF LAKE MICHIGAN
LATER TONIGHT INTO TUESDAY MORNING...WITH LIGHT WINDS AND A MOIST
AIRMASS OVER THE REGION. NOT EXPECTING WIDESPREAD DENSE FOG AT THIS
TIME...BUT WILL NEED TO BE MONITORED BY LATER SHIFTS.
MORE SHOWERS AND STORMS ARE FORECAST BY TUESDAY AFTERNOON...WITH THE
BEST CHANCES TUESDAY NIGHT INTO EARLY WEDNESDAY...AS STRONG LOW
PRESSURE MOVES THROUGH THE REGION.
A TIGHT PRESSURE GRADIENT ON WEDNESDAY INTO THURSDAY SHOULD LEAD TO
WINDY CONDITIONS ACROSS THE NEARSHORE WATERS. WINDS SHOULD BE
OFFSHORE DURING THIS TIME. GALE FORCE GUSTS MAY BE POSSIBLE AT
TIMES...WITH A SMALL CRAFT ADVISORY LIKELY NEEDED IN LATER
FORECASTS.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TONIGHT/TUESDAY AND AVIATION/MARINE...WOOD
TUESDAY NIGHT THROUGH MONDAY...HENTZ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
128 PM CDT SUN AUG 16 2015
.UPDATE...
ISSUED AT 124 PM CDT SUN AUG 16 2015
HAVE ASSESSED MANY ITEMS OVER THE PAST HOURS INCLUDING
TEMPERATURES WITH UPSTREAM CONVECTION AND CLOUD DEBRIS...AS
WELL AS THE OVERNIGHT RAIN TRENDS.
HEAT. HAVE DECIDED TO STAY THE COURSE ON MUCH OF THE MAX
TEMPERATURE GRID WITH DEBRIS CLOUD HOLDING FROM NC WI INTO NC
IA...PROVIDING A MORE CLEAR SKY AND WARMTH OVER CTRL/SWRN WI. A
BIT OF RELIEF /1-3F/ IN THE DEWPOINTS HAS HELPED WITH COMFORT...AS
WELL AS THE LIMITED CLOUD.
OVERNIGHT RAINFALL POTENTIAL. CONFIDENCE HAS ACTUALLY LOWERED A
BIT THROUGH THE MORNING ON THE OVERALL TIMING AND POTENTIAL
RAINFALL. MAIN PROBLEM IS THE LACK OF INSTABILITY AND LIMITED
CONVERGENCE WITH THE FRONT TO CAUSE WIDESPREAD RAINFALL AND TSRA.
MUCAPE VALUES SEEM TO NEVER GET HIGHER THAN 500-750 J/KG.
THE AREA OF CONVECTION IN SWRN MN/SERN SD WILL TRY TO SHIFT EAST
INTO THE WRN FORECAST AREA THIS EVENING. HOWEVER...THERE IS SOME
HIRES MODEL SOLUTION CLUSTERS THAT TAKE THE MOST CONVECTIVE AREA
SEWRD AND NOT INTO THE FORECAST AREA. THAT IS ACTUALLY OCCURRING
RIGHT NOW IN SERN SD AS THE HIGHER CAPE POOL IS OVER NEB AND INTO
SERN SD. ANOTHER GROUP OF SOLUTIONS SEEMS TO SAY ROBUST TSRA
CLUSTERS WILL SHIFT IN DURING THE EARLY-MID EVENING IN THE WRN
FORECAST AREA /HI RES WINDOWS AND NAM NEST/...AND SHIFT EAST. THAT
SEEMS TOO EXCITED PER CAPE THAT IS OUT THERE AND AVAILABLE TO THE
SYSTEM UNDER THE CLOUD VEIL. THINKING IS A BLEND OF THEM BOTH WITH
SHRA AND SCT TSRA OVERNIGHT MOVING IN FROM THE WEST...WITH
GREATEST RAINFALL RATES AND TSRA COVERAGE OVER THE WEST...BEFORE
ANY CAPE DIMINISHES FURTHER OVERNIGHT AND FURTHER EAST.
BOTTOM LINE IS THIS ISNT QUITE A SLAM DUNK. ONE FACTOR THAT WILL
INCREASE RAIN CHANCES OVER THE AREA IS THAT ELEMENTS WILL BE
MOVING SLOWLY ALONG THE SLOWLY MOVING FRONT...ALLOWING MORE
RAIN COVERAGE.
MPX HAS ISSUED A FLASH FLOOD WATCH. WITH LIMITED INSTABILITY
OVERNIGHT AND VERY DRY SOILS...HAVE DECIDED TO HOLD OFF ON THAT
FOR NOW. WILL CONTINUE TO ASSESS INSTABILITY AND DURATION OF
INCOMING RAIN.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 334 AM CDT SUN AUG 16 2015
THE SURFACE COLD FRONT EXTENDED FROM NORTHWEST MINNESOTA INTO
CENTRAL SOUTH DAKOTA EARLY THIS MORNING WITH A LINE OF CONVECTION
ALONG AND AHEAD OF IT. THIS LINE OF CONVECTION IS ON THE EASTERN
EDGE OF THE INSTABILITY GRADIENT WITH THE LATEST ANALYSIS SHOWING
THE MU CAPE DROPPING DOWN TO LESS THAN 500 J/KG WELL NORTHWEST OF
THE TWIN CITIES. THE 16.05Z RAP DOES SUGGEST THIS INSTABILITY AXIS
WILL PROGRESS TO THE EAST BUT SHOULD CONTINUE TO WEAKEN AND REMAIN
TO THE NORTHWEST OF THE AREA THROUGH 12Z. THE 16.06Z HRRR SUGGEST
THIS ACTIVITY WILL CONTINUE TO ADVANCE SOUTHEAST BUT WEAKEN IN
CONCERT WITH THE WEAKENING INSTABILITY AND DISSIPATE BEFORE
REACHING THE FORECAST AREA THIS MORNING. BY MID MORNING...THE COLD
FRONT SHOULD EXTEND FROM NORTHEAST MINNESOTA INTO SOUTHEAST
MINNESOTA WITH THE HI-RES MODELS SUGGESTING THE NEXT ROUND OF
CONVECTION WILL DEVELOP ALONG THE FRONT OVER SOUTHWEST MINNESOTA.
THE FRONT WILL THEN SLOW ITS EASTWARD PROGRESS THROUGH THE
REMAINDER OF THE DAY WITH THE MAJORITY OF THE CONVECTION EXPECTED
TO REMAIN ALONG AND BEHIND THE FRONT AS THE POSITIVE TILT SWEEPS
ACROSS THE HIGH PLAINS. THE HI-RES MODELS ALSO SHOW THE CONVECTION
REMAINING ALONG AND BEHIND THE FRONT WITH JUST A SMALL CHANCE OF
SOME SNEAKING INTO THE NORTHWEST SECTIONS OF THE AREA LATE THIS
AFTERNOON.
SOME UNCERTAINTY ON WHAT WILL HAPPEN TO THIS LINE OF CONVECTION
TONIGHT. THE HI-RES MESO MODELS ALL SHOW THIS WEAKENING AS THE
EVENING PROGRESSES WITH A SUGGESTION THAT THE LINE COULD TOTALLY
DISSIPATE. THIS IS NOT OUT OF THE QUESTION GIVEN THE FORCING FROM
THE POSITIVE TILT TROUGH WILL BE DISSIPATING AS THE SHORT WAVE
TROUGH PULLS OUT INTO CENTRAL ONTARIO. THIS WOULD LEAVE THE LINE
TO BE THERMODYNAMICALLY DRIVEN AND WITH WEAKENING CAPE AND
FRONTOGENESIS COULD EASILY SEE THE LINE BREAKING UP. THE LARGER
SCALE MODELS COMPENSATE FOR THE WEAKENING THERMODYNAMICS WITH
SUPPORT FROM THE RIGHT ENTRANCE REGION OF THE UPPER LEVEL JET AND
SOME WEAK MOISTURE TRANSPORT INTO THE FRONT FROM THE LOW LEVEL
JET. THESE MODELS THEN HOLD THE LINE OF CONVECTION TOGETHER
BRINGING THE BAND INTO THE NORTHWEST SECTIONS OF THE FORECAST AREA
OVERNIGHT. TO HONOR THE HI-RES MODELS HAVE LOWERED THE RAIN
CHANCES JUST A LITTLE BIT OVERNIGHT. THE CHANCES FOR SEVERE LOOK
PRETTY SLIM AS THE BEST INSTABILITY WILL REMAIN TO THE NORTHWEST
TODAY AND THEN DIMINISH RAPIDLY THROUGH THE EVENING INTO THE
OVERNIGHT.
THE FRONT WILL CONTINUE TO SAG SOUTH ACROSS THE AREA MONDAY BUT
THERE SHOULD AGAIN BE THE LACK OF FORCING AS THERE DOES NOT LOOK
TO BE ANY SHORT WAVE TROUGHS COMING THROUGH TO INTERACT WITH THE
FRONT. THE THERMODYNAMICS WILL GET STRONGER THROUGH THE DAY AS THE
INSTABILITY SLOWLY BUILDS AND THE FRONTOGENESIS GETS A LITTLE
STRONGER IN THE 1000-850 MB LAYER. HOWEVER...BY THE TIME THE
FRONTOGENESIS STRENGTHENS THE FRONT MAY BE FAR ENOUGH SOUTH TO
KEEP MOST OF THE CONVECTION TO THE SOUTHEAST OF THE AREA. PLAN TO
STAY WITH THE TRENDS OF THE PREVIOUS FORECAST OF A SLOWLY
WEAKENING LINE OF CONVECTION WORKING SOUTH ACROSS THE AREA ALONG
AND BEHIND THE FRONT.
THE 16.00Z MODELS THEN START TO DIVERGE ON THEIR SOLUTIONS FOR
MONDAY NIGHT INTO TUESDAY. THE NAM AND ECMWF STALL THE FRONT OUT
MONDAY NIGHT FROM SOUTHERN WISCONSIN OR NORTHERN ILLINOIS INTO
SOUTHERN NEBRASKA WHILE THE GFS PUSHES THE FRONT FARTHER SOUTH
INTO ILLINOIS. WITH THESE DIFFERENCES IN THE POSITION OF THE FRONT
THERE IS SOME QUESTION ON HOW MUCH RAIN WILL BE OVER THE AREA AND
HAVE STAYED WITH THE TRENDS OF THE PREVIOUS FORECAST OF SHOWING A
30 TO 50 PERCENT CHANCE OVER MUCH OF THE AREA WITH THE BEST
CHANCES ACROSS THE SOUTH. THE NAM AND ECMWF THEN INDICATE THE
FRONT WILL NOT MOVE MUCH TUESDAY WHILE THE GFS PULLS IT BACK INTO
THE AREA AS IT DEVELOPS A SURFACE LOW AND MOVES THIS UP THE
MISSOURI RIVER VALLEY. THESE DIFFERENCES COME ABOUT FROM THE
DIFFERENCES IN HANDLING THE NEXT SHORT WAVE TROUGH THAT COMES IN
FROM THE NORTHWEST. ALL THE MODELS BRING THIS WAVE IN AND SUGGEST
IT WILL BE STRENGTHENING AS IT APPROACHES BUT THE GFS IS THE
STRONGEST WITH IT. FOR NOW...THESE DIFFERENCES DO NOT HAVE TOO
MUCH IMPACT ON THE FORECAST AS ALL SHOW THE FORCING INCREASING AND
WITH THE FRONT STILL IN THE AREA...SHOULD SEE WIDESPREAD SHOWERS
AND STORMS DEVELOP...ESPECIALLY IN THE AFTERNOON ALONG AND
SOUTHWEST OF THE INTERSTATE 94 CORRIDOR. THESE DIFFERENCES DO
IMPACT THE POTENTIAL FOR SEVERE WEATHER. WITH THE NAM AND ECMWF
SCENARIO...THE INSTABILITY WILL REMAIN TO THE SOUTH OF THE AREA
WHILE THE GFS WOULD BRING THIS IN BEHIND THE WARM FRONT. PLAN TO
TREND TOWARD THE NAM AND ECMWF SOLUTIONS WITH THE SEVERE THREAT
REMAINING SOUTH OF THE AREA.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 334 AM CDT SUN AUG 16 2015
TUESDAY NIGHT IS SHAPING UP TO BE A WET ONE AT THIS POINT AS THE
NAM AND ECMWF DO SPIN UP A SURFACE LOW ALONG THE FRONT AS THE
SHORT WAVE TROUGH CONTINUES TO INTENSIFY OVER THE UPPER MIDWEST.
STILL SOME DIFFERENCES ON THE TRACK OF THE SURFACE LOW WITH THE
NAM KEEPING IT EAST OF THE AREA WHILE THE ECMWF BRINGS UP THROUGH
THE FORECAST AREA. EITHER WAY...THERE SHOULD BE AMPLE FORCING FROM
THE SHORT WAVE THROUGH TO PRODUCE WIDESPREAD SHOWERS AND STORMS
ACROSS MUCH OF THE AREA. THE RAIN CHANCES WILL THEN DIMINISH
WEDNESDAY AS THIS SYSTEM PULLS AWAY WITH THE TRENDS IN THE ECMWF
AND GFS OF THIS PULLING AWAY MUCH QUICKER AND HIGH PRESSURE
BUILDING IN FOR A PERIOD OF DRY WEATHER FROM WEDNESDAY NIGHT
THROUGH FRIDAY. IN COLLABORATION WITH SURROUNDING OFFICES...HAVE
LOWERED THE MODEL CONSENSUS RAIN CHANCES WEDNESDAY NIGHT AND
THURSDAY AND WENT DRY FOR THURSDAY NIGHT AND FRIDAY. THE RAIN
CHANCES WILL THEN RETURN FOR NEXT WEEKEND WITH THE POTENTIAL OF
ANOTHER COLD FRONT COMING IN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 124 PM CDT SUN AUG 16 2015
THIS FORECAST WAS A TOUGH ONE TO BUILD DETAILS INTO AS CONFIDENCE
WAS BELOW NORMAL. A SLOW MOVING FRONT WILL MOVE THROUGH THE TAF
SITES TONIGHT. LIMITED OR WANING INSTABILITY PROVIDES A CHALLENGE
AS TO THE INTENSITY OF THE STORMS AND THUS THE CIG/VSBY. ARRIVAL
OF THE FIRST TSRA CHANCES ARE ALSO OF LOW CONFIDENCE AS THE
INSTABILITY IS IN A FAIRLY NARROW CHANNEL RIGHT ALONG THE FRONT.
HI RESOLUTION MODELS ARE SUGGESTING QUITE A SPREAD IN THE OUTCOMES
FOR THE OVERNIGHT. OVERALL...DID NOT FEEL COMFORTABLE WITH MANY
HOURS OF TSRA IN THE TAFS AND HAVE REDUCED THEM VIA A PERIOD OF
TEMPO. UPDATES WILL DEFINITELY FOLLOW AS THE TRENDS BECOME MORE
CLEAR.
FRONT MAY STALL OR SLOW ACROSS THE AREA AS ANOTHER WEATHER SYSTEM
APPROACHES DURING THE DAY MONDAY. HAVE FORECAST A FAIRLY DRY
MONDAY MORNING BUT THERE COULD BE REDEVELOPMENT OF WHAT LOOKS TO
BE AN MVFR SHRA. AGAIN LOWER CONFIDENCE HERE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...BAUMGARDT
SHORT TERM...04
LONG TERM...04
AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
652 AM CDT SUN AUG 16 2015
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 334 AM CDT SUN AUG 16 2015
THE SURFACE COLD FRONT EXTENDED FROM NORTHWEST MINNESOTA INTO
CENTRAL SOUTH DAKOTA EARLY THIS MORNING WITH A LINE OF CONVECTION
ALONG AND AHEAD OF IT. THIS LINE OF CONVECTION IS ON THE EASTERN
EDGE OF THE INSTABILITY GRADIENT WITH THE LATEST ANALYSIS SHOWING
THE MU CAPE DROPPING DOWN TO LESS THAN 500 J/KG WELL NORTHWEST OF
THE TWIN CITIES. THE 16.05Z RAP DOES SUGGEST THIS INSTABILITY AXIS
WILL PROGRESS TO THE EAST BUT SHOULD CONTINUE TO WEAKEN AND REMAIN
TO THE NORTHWEST OF THE AREA THROUGH 12Z. THE 16.06Z HRRR SUGGEST
THIS ACTIVITY WILL CONTINUE TO ADVANCE SOUTHEAST BUT WEAKEN IN
CONCERT WITH THE WEAKENING INSTABILITY AND DISSIPATE BEFORE
REACHING THE FORECAST AREA THIS MORNING. BY MID MORNING...THE COLD
FRONT SHOULD EXTEND FROM NORTHEAST MINNESOTA INTO SOUTHEAST
MINNESOTA WITH THE HI-RES MODELS SUGGESTING THE NEXT ROUND OF
CONVECTION WILL DEVELOP ALONG THE FRONT OVER SOUTHWEST MINNESOTA.
THE FRONT WILL THEN SLOW ITS EASTWARD PROGRESS THROUGH THE
REMAINDER OF THE DAY WITH THE MAJORITY OF THE CONVECTION EXPECTED
TO REMAIN ALONG AND BEHIND THE FRONT AS THE POSITIVE TILT SWEEPS
ACROSS THE HIGH PLAINS. THE HI-RES MODELS ALSO SHOW THE CONVECTION
REMAINING ALONG AND BEHIND THE FRONT WITH JUST A SMALL CHANCE OF
SOME SNEAKING INTO THE NORTHWEST SECTIONS OF THE AREA LATE THIS
AFTERNOON.
SOME UNCERTAINTY ON WHAT WILL HAPPEN TO THIS LINE OF CONVECTION
TONIGHT. THE HI-RES MESO MODELS ALL SHOW THIS WEAKENING AS THE
EVENING PROGRESSES WITH A SUGGESTION THAT THE LINE COULD TOTALLY
DISSIPATE. THIS IS NOT OUT OF THE QUESTION GIVEN THE FORCING FROM
THE POSITIVE TILT TROUGH WILL BE DISSIPATING AS THE SHORT WAVE
TROUGH PULLS OUT INTO CENTRAL ONTARIO. THIS WOULD LEAVE THE LINE
TO BE THERMODYNAMICALLY DRIVEN AND WITH WEAKENING CAPE AND
FRONTOGENESIS COULD EASILY SEE THE LINE BREAKING UP. THE LARGER
SCALE MODELS COMPENSATE FOR THE WEAKENING THERMODYNAMICS WITH
SUPPORT FROM THE RIGHT ENTRANCE REGION OF THE UPPER LEVEL JET AND
SOME WEAK MOISTURE TRANSPORT INTO THE FRONT FROM THE LOW LEVEL
JET. THESE MODELS THEN HOLD THE LINE OF CONVECTION TOGETHER
BRINGING THE BAND INTO THE NORTHWEST SECTIONS OF THE FORECAST AREA
OVERNIGHT. TO HONOR THE HI-RES MODELS HAVE LOWERED THE RAIN
CHANCES JUST A LITTLE BIT OVERNIGHT. THE CHANCES FOR SEVERE LOOK
PRETTY SLIM AS THE BEST INSTABILITY WILL REMAIN TO THE NORTHWEST
TODAY AND THEN DIMINISH RAPIDLY THROUGH THE EVENING INTO THE
OVERNIGHT.
THE FRONT WILL CONTINUE TO SAG SOUTH ACROSS THE AREA MONDAY BUT
THERE SHOULD AGAIN BE THE LACK OF FORCING AS THERE DOES NOT LOOK
TO BE ANY SHORT WAVE TROUGHS COMING THROUGH TO INTERACT WITH THE
FRONT. THE THERMODYNAMICS WILL GET STRONGER THROUGH THE DAY AS THE
INSTABILITY SLOWLY BUILDS AND THE FRONTOGENESIS GETS A LITTLE
STRONGER IN THE 1000-850 MB LAYER. HOWEVER...BY THE TIME THE
FRONTOGENESIS STRENGTHENS THE FRONT MAY BE FAR ENOUGH SOUTH TO
KEEP MOST OF THE CONVECTION TO THE SOUTHEAST OF THE AREA. PLAN TO
STAY WITH THE TRENDS OF THE PREVIOUS FORECAST OF A SLOWLY
WEAKENING LINE OF CONVECTION WORKING SOUTH ACROSS THE AREA ALONG
AND BEHIND THE FRONT.
THE 16.00Z MODELS THEN START TO DIVERGE ON THEIR SOLUTIONS FOR
MONDAY NIGHT INTO TUESDAY. THE NAM AND ECMWF STALL THE FRONT OUT
MONDAY NIGHT FROM SOUTHERN WISCONSIN OR NORTHERN ILLINOIS INTO
SOUTHERN NEBRASKA WHILE THE GFS PUSHES THE FRONT FARTHER SOUTH
INTO ILLINOIS. WITH THESE DIFFERENCES IN THE POSITION OF THE FRONT
THERE IS SOME QUESTION ON HOW MUCH RAIN WILL BE OVER THE AREA AND
HAVE STAYED WITH THE TRENDS OF THE PREVIOUS FORECAST OF SHOWING A
30 TO 50 PERCENT CHANCE OVER MUCH OF THE AREA WITH THE BEST
CHANCES ACROSS THE SOUTH. THE NAM AND ECMWF THEN INDICATE THE
FRONT WILL NOT MOVE MUCH TUESDAY WHILE THE GFS PULLS IT BACK INTO
THE AREA AS IT DEVELOPS A SURFACE LOW AND MOVES THIS UP THE
MISSOURI RIVER VALLEY. THESE DIFFERENCES COME ABOUT FROM THE
DIFFERENCES IN HANDLING THE NEXT SHORT WAVE TROUGH THAT COMES IN
FROM THE NORTHWEST. ALL THE MODELS BRING THIS WAVE IN AND SUGGEST
IT WILL BE STRENGTHENING AS IT APPROACHES BUT THE GFS IS THE
STRONGEST WITH IT. FOR NOW...THESE DIFFERENCES DO NOT HAVE TOO
MUCH IMPACT ON THE FORECAST AS ALL SHOW THE FORCING INCREASING AND
WITH THE FRONT STILL IN THE AREA...SHOULD SEE WIDESPREAD SHOWERS
AND STORMS DEVELOP...ESPECIALLY IN THE AFTERNOON ALONG AND
SOUTHWEST OF THE INTERSTATE 94 CORRIDOR. THESE DIFFERENCES DO
IMPACT THE POTENTIAL FOR SEVERE WEATHER. WITH THE NAM AND ECMWF
SCENARIO...THE INSTABILITY WILL REMAIN TO THE SOUTH OF THE AREA
WHILE THE GFS WOULD BRING THIS IN BEHIND THE WARM FRONT. PLAN TO
TREND TOWARD THE NAM AND ECMWF SOLUTIONS WITH THE SEVERE THREAT
REMAINING SOUTH OF THE AREA.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 334 AM CDT SUN AUG 16 2015
TUESDAY NIGHT IS SHAPING UP TO BE A WET ONE AT THIS POINT AS THE
NAM AND ECMWF DO SPIN UP A SURFACE LOW ALONG THE FRONT AS THE
SHORT WAVE TROUGH CONTINUES TO INTENSIFY OVER THE UPPER MIDWEST.
STILL SOME DIFFERENCES ON THE TRACK OF THE SURFACE LOW WITH THE
NAM KEEPING IT EAST OF THE AREA WHILE THE ECMWF BRINGS UP THROUGH
THE FORECAST AREA. EITHER WAY...THERE SHOULD BE AMPLE FORCING FROM
THE SHORT WAVE THROUGH TO PRODUCE WIDESPREAD SHOWERS AND STORMS
ACROSS MUCH OF THE AREA. THE RAIN CHANCES WILL THEN DIMINISH
WEDNESDAY AS THIS SYSTEM PULLS AWAY WITH THE TRENDS IN THE ECMWF
AND GFS OF THIS PULLING AWAY MUCH QUICKER AND HIGH PRESSURE
BUILDING IN FOR A PERIOD OF DRY WEATHER FROM WEDNESDAY NIGHT
THROUGH FRIDAY. IN COLLABORATION WITH SURROUNDING OFFICES...HAVE
LOWERED THE MODEL CONSENSUS RAIN CHANCES WEDNESDAY NIGHT AND
THURSDAY AND WENT DRY FOR THURSDAY NIGHT AND FRIDAY. THE RAIN
CHANCES WILL THEN RETURN FOR NEXT WEEKEND WITH THE POTENTIAL OF
ANOTHER COLD FRONT COMING IN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 652 AM CDT SUN AUG 16 2015
VFR CONDITIONS ARE EXPECTED THROUGH EARLY THIS EVENING THEN
SHOWERS AND THUNDERSTORMS ARE EXPECTED DURING THE OVERNIGHT HOURS
WITH IFR CONDITIONS POSSIBLE AT TIMES. A COLD FRONT WILL TRACK
SOUTHEAST ACROSS MINNESOTA AND NORTHWEST WISCONSIN...APPROACHING
THE TAF SITES LATE THIS EVENING INTO THE OVERNIGHT HOURS. SHOWERS
AND THUNDERSTORMS ARE EXPECTED ALONG THE FRONT. THIS ACTIVITY LOOKS
TO PUSH INTO SOUTHEAST MINNESOTA AROUND 03Z...IMPACTING KRST. THE
SHOWERS AND STORMS LOOK TO IMPACT KLSE ALSO...STARTING AROUND 07Z.
PERIODS OF SHOWERS AND STORMS ARE THEN POSSIBLE THROUGH 12Z.
CONDITIONS COULD LOWER TO IFR WITH VISIBILITIES REDUCED TO 2SM AT
TIMES IN BR AND BRIEF HEAVY RAIN.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...04
LONG TERM...04
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
334 AM CDT SUN AUG 16 2015
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 334 AM CDT SUN AUG 16 2015
THE SURFACE COLD FRONT EXTENDED FROM NORTHWEST MINNESOTA INTO
CENTRAL SOUTH DAKOTA EARLY THIS MORNING WITH A LINE OF CONVECTION
ALONG AND AHEAD OF IT. THIS LINE OF CONVECTION IS ON THE EASTERN
EDGE OF THE INSTABILITY GRADIENT WITH THE LATEST ANALYSIS SHOWING
THE MU CAPE DROPPING DOWN TO LESS THAN 500 J/KG WELL NORTHWEST OF
THE TWIN CITIES. THE 16.05Z RAP DOES SUGGEST THIS INSTABILITY AXIS
WILL PROGRESS TO THE EAST BUT SHOULD CONTINUE TO WEAKEN AND REMAIN
TO THE NORTHWEST OF THE AREA THROUGH 12Z. THE 16.06Z HRRR SUGGEST
THIS ACTIVITY WILL CONTINUE TO ADVANCE SOUTHEAST BUT WEAKEN IN
CONCERT WITH THE WEAKENING INSTABILITY AND DISSIPATE BEFORE
REACHING THE FORECAST AREA THIS MORNING. BY MID MORNING...THE COLD
FRONT SHOULD EXTEND FROM NORTHEAST MINNESOTA INTO SOUTHEAST
MINNESOTA WITH THE HI-RES MODELS SUGGESTING THE NEXT ROUND OF
CONVECTION WILL DEVELOP ALONG THE FRONT OVER SOUTHWEST MINNESOTA.
THE FRONT WILL THEN SLOW ITS EASTWARD PROGRESS THROUGH THE
REMAINDER OF THE DAY WITH THE MAJORITY OF THE CONVECTION EXPECTED
TO REMAIN ALONG AND BEHIND THE FRONT AS THE POSITIVE TILT SWEEPS
ACROSS THE HIGH PLAINS. THE HI-RES MODELS ALSO SHOW THE CONVECTION
REMAINING ALONG AND BEHIND THE FRONT WITH JUST A SMALL CHANCE OF
SOME SNEAKING INTO THE NORTHWEST SECTIONS OF THE AREA LATE THIS
AFTERNOON.
SOME UNCERTAINTY ON WHAT WILL HAPPEN TO THIS LINE OF CONVECTION
TONIGHT. THE HI-RES MESO MODELS ALL SHOW THIS WEAKENING AS THE
EVENING PROGRESSES WITH A SUGGESTION THAT THE LINE COULD TOTALLY
DISSIPATE. THIS IS NOT OUT OF THE QUESTION GIVEN THE FORCING FROM
THE POSITIVE TILT TROUGH WILL BE DISSIPATING AS THE SHORT WAVE
TROUGH PULLS OUT INTO CENTRAL ONTARIO. THIS WOULD LEAVE THE LINE
TO BE THERMODYNAMICALLY DRIVEN AND WITH WEAKENING CAPE AND
FRONTOGENESIS COULD EASILY SEE THE LINE BREAKING UP. THE LARGER
SCALE MODELS COMPENSATE FOR THE WEAKENING THERMODYNAMICS WITH
SUPPORT FROM THE RIGHT ENTRANCE REGION OF THE UPPER LEVEL JET AND
SOME WEAK MOISTURE TRANSPORT INTO THE FRONT FROM THE LOW LEVEL
JET. THESE MODELS THEN HOLD THE LINE OF CONVECTION TOGETHER
BRINGING THE BAND INTO THE NORTHWEST SECTIONS OF THE FORECAST AREA
OVERNIGHT. TO HONOR THE HI-RES MODELS HAVE LOWERED THE RAIN
CHANCES JUST A LITTLE BIT OVERNIGHT. THE CHANCES FOR SEVERE LOOK
PRETTY SLIM AS THE BEST INSTABILITY WILL REMAIN TO THE NORTHWEST
TODAY AND THEN DIMINISH RAPIDLY THROUGH THE EVENING INTO THE
OVERNIGHT.
THE FRONT WILL CONTINUE TO SAG SOUTH ACROSS THE AREA MONDAY BUT
THERE SHOULD AGAIN BE THE LACK OF FORCING AS THERE DOES NOT LOOK
TO BE ANY SHORT WAVE TROUGHS COMING THROUGH TO INTERACT WITH THE
FRONT. THE THERMODYNAMICS WILL GET STRONGER THROUGH THE DAY AS THE
INSTABILITY SLOWLY BUILDS AND THE FRONTOGENESIS GETS A LITTLE
STRONGER IN THE 1000-850 MB LAYER. HOWEVER...BY THE TIME THE
FRONTOGENESIS STRENGTHENS THE FRONT MAY BE FAR ENOUGH SOUTH TO
KEEP MOST OF THE CONVECTION TO THE SOUTHEAST OF THE AREA. PLAN TO
STAY WITH THE TRENDS OF THE PREVIOUS FORECAST OF A SLOWLY
WEAKENING LINE OF CONVECTION WORKING SOUTH ACROSS THE AREA ALONG
AND BEHIND THE FRONT.
THE 16.00Z MODELS THEN START TO DIVERGE ON THEIR SOLUTIONS FOR
MONDAY NIGHT INTO TUESDAY. THE NAM AND ECMWF STALL THE FRONT OUT
MONDAY NIGHT FROM SOUTHERN WISCONSIN OR NORTHERN ILLINOIS INTO
SOUTHERN NEBRASKA WHILE THE GFS PUSHES THE FRONT FARTHER SOUTH
INTO ILLINOIS. WITH THESE DIFFERENCES IN THE POSITION OF THE FRONT
THERE IS SOME QUESTION ON HOW MUCH RAIN WILL BE OVER THE AREA AND
HAVE STAYED WITH THE TRENDS OF THE PREVIOUS FORECAST OF SHOWING A
30 TO 50 PERCENT CHANCE OVER MUCH OF THE AREA WITH THE BEST
CHANCES ACROSS THE SOUTH. THE NAM AND ECMWF THEN INDICATE THE
FRONT WILL NOT MOVE MUCH TUESDAY WHILE THE GFS PULLS IT BACK INTO
THE AREA AS IT DEVELOPS A SURFACE LOW AND MOVES THIS UP THE
MISSOURI RIVER VALLEY. THESE DIFFERENCES COME ABOUT FROM THE
DIFFERENCES IN HANDLING THE NEXT SHORT WAVE TROUGH THAT COMES IN
FROM THE NORTHWEST. ALL THE MODELS BRING THIS WAVE IN AND SUGGEST
IT WILL BE STRENGTHENING AS IT APPROACHES BUT THE GFS IS THE
STRONGEST WITH IT. FOR NOW...THESE DIFFERENCES DO NOT HAVE TOO
MUCH IMPACT ON THE FORECAST AS ALL SHOW THE FORCING INCREASING AND
WITH THE FRONT STILL IN THE AREA...SHOULD SEE WIDESPREAD SHOWERS
AND STORMS DEVELOP...ESPECIALLY IN THE AFTERNOON ALONG AND
SOUTHWEST OF THE INTERSTATE 94 CORRIDOR. THESE DIFFERENCES DO
IMPACT THE POTENTIAL FOR SEVERE WEATHER. WITH THE NAM AND ECMWF
SCENARIO...THE INSTABILITY WILL REMAIN TO THE SOUTH OF THE AREA
WHILE THE GFS WOULD BRING THIS IN BEHIND THE WARM FRONT. PLAN TO
TREND TOWARD THE NAM AND ECMWF SOLUTIONS WITH THE SEVERE THREAT
REMAINING SOUTH OF THE AREA.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 334 AM CDT SUN AUG 16 2015
TUESDAY NIGHT IS SHAPING UP TO BE A WET ONE AT THIS POINT AS THE
NAM AND ECMWF DO SPIN UP A SURFACE LOW ALONG THE FRONT AS THE
SHORT WAVE TROUGH CONTINUES TO INTENSIFY OVER THE UPPER MIDWEST.
STILL SOME DIFFERENCES ON THE TRACK OF THE SURFACE LOW WITH THE
NAM KEEPING IT EAST OF THE AREA WHILE THE ECMWF BRINGS UP THROUGH
THE FORECAST AREA. EITHER WAY...THERE SHOULD BE AMPLE FORCING FROM
THE SHORT WAVE THROUGH TO PRODUCE WIDESPREAD SHOWERS AND STORMS
ACROSS MUCH OF THE AREA. THE RAIN CHANCES WILL THEN DIMINISH
WEDNESDAY AS THIS SYSTEM PULLS AWAY WITH THE TRENDS IN THE ECMWF
AND GFS OF THIS PULLING AWAY MUCH QUICKER AND HIGH PRESSURE
BUILDING IN FOR A PERIOD OF DRY WEATHER FROM WEDNESDAY NIGHT
THROUGH FRIDAY. IN COLLABORATION WITH SURROUNDING OFFICES...HAVE
LOWERED THE MODEL CONSENSUS RAIN CHANCES WEDNESDAY NIGHT AND
THURSDAY AND WENT DRY FOR THURSDAY NIGHT AND FRIDAY. THE RAIN
CHANCES WILL THEN RETURN FOR NEXT WEEKEND WITH THE POTENTIAL OF
ANOTHER COLD FRONT COMING IN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1151 PM CDT SAT AUG 15 2015
MOSTLY CLEAR SKIES WILL PERSIST AT KLSE/KRST OVERNIGHT WITH LIGHT
SOUTHERLY WINDS. EXPECT A GRADUAL INCREASE OF MID-HIGH LEVEL
CLOUDS LATE SUNDAY AFTERNOON INTO THE EVENING WITH APPROACHING
SURFACE TROUGH...BUT ANY CEILINGS EXPECTED TO REMAIN ABOVE 3000 FT
AGL. INTRODUCED VCTS/CB AT KRST AT 17.03Z...BUT TIMING OF SUNDAY
NIGHT CONVECTION WILL NEED TO BE FINE-TUNED WITH LATER FORECASTS.
SOME SOUTHERLY-SOUTHWESTERLY WIND GUSTS TO AROUND 20 KTS POSSIBLE
AT BOTH TAF SITES LATE SUNDAY MORNING/AFTERNOON. OTHERWISE...WINDS
WILL BE LIGHT GENERALLY FROM THE SOUTH-SOUTHWEST THROUGH THE
PERIOD.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...04
LONG TERM...04
AVIATION...ROGERS
AREA FORECAST DISCUSSION...UPDATED
NWS CHEYENNE WY
923 PM MDT MON AUG 17 2015
.UPDATE...
ISSUED AT 923 PM MDT MON AUG 17 2015
DROPPED THE SEVERE THUNDERSTORM WATCH FOR ALBANY AND LARAMIE
COUNTIES GIVEN 13 DEGREE 700 MB CAP THAT WILL PRECLUDE MOST OF ANY
SEVERE STORMS THOSE AREAS OVERNIGHT. COOLER MIDLEVEL TEMPS FARTHER
NORTH INTO EAST CENTRAL WY COULD RESULT IN A FEW STRONG TO
MARGINALLY SEVERE STORMS THROUGH LATE EVENING ON THE SOUTH SIDE OF
THE NORTHERN COMPLEX OF STORMS...HOWEVER SEVERE WEATHER THREAT
BEYOND 10 PM NOT SUFFICIENT AND THINKING IS WE WILL NOT BE
REISSUING A WATCH WHEN THE CURRENT WATCH EXPIRES. LEFT NUMEROUS
SHOWERS WITH SCATTERED STORMS IN THE NORTHEASTERN ZONES THROUGH
LATE TONIGHT AND SCATTERED SHOWERS/ISOLATED STORMS IN THE
SOUTHEASTERN ZONES GIVEN CAP...AND THE STORMS WE DO GET DOWN SOUTH
WILL MOSTLY BE ELEVATED.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 235 PM MDT MON AUG 17 2015
FORECAST CHALLENGES DEAL WITH A VARIETY OF TOPICS THIS AFTERNOON.
WE HAVE CHANCES FOR SEVERE THUNDERSTORMS EAST OF THE LARAMIE
RANGE...RED FLAG CONCERNS OUT WEST AND THEN THE RETURN OF FOG AND
STRATUS TONIGHT.
CURRENTLY...LATEST VISIBLE IMAGERY SHOWING STRATUS LAYER HANGING
TOUGH GENERALLY ALONG AND SOUTH OF A LINE FROM GLENDO TO ALLIANCE
THIS AFTERNOON. LATEST SPC MESOANALYST PAGE SHOWING A SOLIDLY
CAPPED ENVIRONMENT UNDER THIS STRATUS WITH CONVECTIVE INHIBITION
ANYWHERE FROM -50 J/KG UP BY WHEATLAND TO -300 J/KG OUT BY SIDNEY.
CONVERSE...NIOBRARA COUNTIES IN EAST CENTRAL WYOMING AND THE
NORTHERN PANHANDLE HAS BEGUN TO BREAK OUT WITH TEMPERATURES
CLIMBING INTO THE LOW 70S AS OF 1 PM. IR IMAGERY SHOWING AN UPPER
SHORTWAVE TRACKING INTO SOUTH CENTRAL MONTANA AND NORTH CENTRAL
WYOMING THIS AFTERNOON. NEED TO BE WATCHING OUR NORTHERN COUNTIES
TODAY FOR POSSIBLE SEVERE THUNDERSTORM DEVELOPMENT. LATEST SPC DAY
1 OUTLOOK WAS EXPANDED NORTH TO INCLUDE THIS AREA AS WELL AS
WESTERN SOUTH DAKOTA AND NORTHEASTERN WYOMING. DID REMOVE SEVERE
THUNDERSTORM WORDING FROM OUR SOUTHERN ZONES AS THEY WILL MOST
LIKELY STAY IN STRATUS THROUGH THE AFTERNOON.
DID INTRODUCE SEVERE THUNDERSTORMS ACROSS OUR NORTHERN ZONES FOR
EARLY THIS EVENING. THAT SHORTWAVE MOVES INTO NORTHWESTERN SOUTH
DAKOTA. LATEST HRRR SIMULATED RADAR SHOWING SOME PRETTY STRONG
STORMS DEVELOPING ALONG A SQUALL LINE THAT DEVELOPS AFTER 00Z THAT
COULD PERSIST INTO THE LATE EVENING HOURS. STILL VERY CONDITIONAL
THOUGH AS LATEST MESOANALYSIS PAGE CAPS OFF LOW LEVELS AFTER
SUNSET. WOULD THINK THE ASSOCIATED SURFACE TROUGH/FRONT WITH THE
UPPER SHORTWAVE WOULD BREAK THAT CAP THOUGH.
TO THE WEST...KEPT CURRENT FIRE HEADLINES GOING AS THEY ARE FOR
FWZ 304 AND 306. THEY ARE VERY CLOSE TO VERIFYING RIGHT NOW...SO
RED FLAG WARNINGS ARE ON TRACK. NO CHANGES PLANNED.
THERE IS A BRIEF PERIOD THIS EVENING BEFORE THE SURFACE
FRONT/TROUGH MOVES THROUGH THE SOUTHERN CWFA WHERE WE SEE
SOUTHEASTERLY WINDS. WITH CURRENT STRATUS ALREADY IN PLACE...THINK
THERE IS A PERIOD BETWEEN ABOUT 9 PM AND 3 AM WHERE WE COULD SEE
FOG ONCE AGAIN. ONCE THE SURFACE TROUGH MOVES THROUGH...FAIRLY
STRONG NORTHWEST DOWNSLOPING WINDS SHOULD SCOUR OUT FOG/STRATUS
SHORTLY AFTER 06Z OR SO FROM NORTH TO SOUTH.
KEPT POPS GOING FOR OUR EASTERN ZONES WEDNESDAY AS WRAP-AROUND
ENERGY FROM THE DEPARTING LOW IMPACTS THE PANHANDLE AND MAYBE OUR
EXTREME EASTERN COUNTIES.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 235 PM MDT MON AUG 17 2015
A GENERALLY DRY AND MILD/WARM PATTERN EXPECTED TO PREVAIL AVER THE
CWA DURING THE PERIOD. TEMPERATURES WILL TURN WARMER THURSDAY AS
DOWNSLOPE FLOW DEVELOPS IN RESPONSE TO LEE TROFFING SETTING UP
OVER THE HIGH PLAINS. THIS WILL CONTINUE THROUGH FRIDAY AHEAD OF A
DIGGING UPPER TROF THAT WILL MOVE INTO THE NRN ROCKYS FRIDAY
NIGHT. THIS WILL PUSH THE NEXT COOL FRONT ACROSS THE CWA SATURDAY
WITH A BIT OF CONVECTION POSSIBLE WITH IT. EC QUICKER THAN THE GFS
WITH THIS SYSTEM BY ABOUT 12 HOURS WITH COULD IMPACT MAX TEMPS FOR
SATURDAY. SUNDAY AND MONDAY DRY AND SEASONAL WITH A BUILDING
UPPER RIDGE OVER THE ROCKY MTNS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 548 PM MDT MON AUG 17 2015
LIFR CONDITIONS IN STRATUS/FOG WILL REMAIN IN PLACE AT KSNY THIS
EVENING WITH MVFR/IFR AT KAIA AND KBFF IN PERSISTENT MOIST UPSLOPE
FLOW AT THE SFC. LOOKING AT VFR CONDITIONS ELSEWHERE...AT
LEAST UNTIL THE SFC COLD FRONT MOVES SOUTHEAST ACROSS THE AREA
AFTER 03Z. WITH THE COLD FRONT WILL COME WIDESPREAD MAINLY
MVFR/IFR CIGS ACROSS THE AREA ALONG WITH SHOWERS/TSTORMS AND
GUSTY NORTHWEST WINDS. STORM CHANCES SHOULD END FROM NW-SE BY
SUNRISE WITH RAIN SHOWERS POSSIBLE THROUGH TUESDAY MORNING.
CONDITIONS SHOULD IMPROVE THROUGH THIS TIME. WIND GUSTS ARE
EXPECTED TO BE 20 TO 30 KTS FOR MOST SITES THRU MUCH OF TUESDAY.
&&
.FIRE WEATHER...
ISSUED AT 923 PM MDT MON AUG 17 2015
EXTENDED THE RED FLAG WARNING FOR PORTIONS OF CARBON COUNTY UNTIL
10 PM GIVEN RH VALUES AROUND 10 PERCENT AND WINDS 30G40 MPH. WINDS
STILL BLOWING TO AROUND 25 MPH BUT RH VALUES STARTING TO GO ABOVE
15 PERCENT SO THINKING IS BY 10 PM WE SHOULD BE OKAY TO DROP THE
RED FLAG WARNING.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING UNTIL 10 PM MDT THIS EVENING FOR WYZ304-306.
NE...NONE.
&&
$$
UPDATE...JG
SHORT TERM...GCC
LONG TERM...RE
AVIATION...RJM
FIRE WEATHER...JG
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
548 PM MDT MON AUG 17 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 235 PM MDT MON AUG 17 2015
FORECAST CHALLENGES DEAL WITH A VARIETY OF TOPICS THIS AFTERNOON.
WE HAVE CHANCES FOR SEVERE THUNDERSTORMS EAST OF THE LARAMIE
RANGE...RED FLAG CONCERNS OUT WEST AND THEN THE RETURN OF FOG AND
STRATUS TONIGHT.
CURRENTLY...LATEST VISIBLE IMAGERY SHOWING STRATUS LAYER HANGING
TOUGH GENERALLY ALONG AND SOUTH OF A LINE FROM GLENDO TO ALLIANCE
THIS AFTERNOON. LATEST SPC MESOANALYST PAGE SHOWING A SOLIDLY
CAPPED ENVIRONMENT UNDER THIS STRATUS WITH CONVECTIVE INHIBITION
ANYWHERE FROM -50 J/KG UP BY WHEATLAND TO -300 J/KG OUT BY SIDNEY.
CONVERSE...NIOBRARA COUNTIES IN EAST CENTRAL WYOMING AND THE
NORTHERN PANHANDLE HAS BEGUN TO BREAK OUT WITH TEMPERATURES
CLIMBING INTO THE LOW 70S AS OF 1 PM. IR IMAGERY SHOWING AN UPPER
SHORTWAVE TRACKING INTO SOUTH CENTRAL MONTANA AND NORTH CENTRAL
WYOMING THIS AFTERNOON. NEED TO BE WATCHING OUR NORTHERN COUNTIES
TODAY FOR POSSIBLE SEVERE THUNDERSTORM DEVELOPMENT. LATEST SPC DAY
1 OUTLOOK WAS EXPANDED NORTH TO INCLUDE THIS AREA AS WELL AS
WESTERN SOUTH DAKOTA AND NORTHEASTERN WYOMING. DID REMOVE SEVERE
THUNDERSTORM WORDING FROM OUR SOUTHERN ZONES AS THEY WILL MOST
LIKELY STAY IN STRATUS THROUGH THE AFTERNOON.
DID INTRODUCE SEVERE THUNDERSTORMS ACROSS OUR NORTHERN ZONES FOR
EARLY THIS EVENING. THAT SHORTWAVE MOVES INTO NORTHWESTERN SOUTH
DAKOTA. LATEST HRRR SIMULATED RADAR SHOWING SOME PRETTY STRONG
STORMS DEVELOPING ALONG A SQUALL LINE THAT DEVELOPS AFTER 00Z THAT
COULD PERSIST INTO THE LATE EVENING HOURS. STILL VERY CONDITIONAL
THOUGH AS LATEST MESOANALYSIS PAGE CAPS OFF LOW LEVELS AFTER
SUNSET. WOULD THINK THE ASSOCIATED SURFACE TROUGH/FRONT WITH THE
UPPER SHORTWAVE WOULD BREAK THAT CAP THOUGH.
TO THE WEST...KEPT CURRENT FIRE HEADLINES GOING AS THEY ARE FOR
FWZ 304 AND 306. THEY ARE VERY CLOSE TO VERIFYING RIGHT NOW...SO
RED FLAG WARNINGS ARE ON TRACK. NO CHANGES PLANNED.
THERE IS A BRIEF PERIOD THIS EVENING BEFORE THE SURFACE
FRONT/TROUGH MOVES THROUGH THE SOUTHERN CWFA WHERE WE SEE
SOUTHEASTERLY WINDS. WITH CURRENT STRATUS ALREADY IN PLACE...THINK
THERE IS A PERIOD BETWEEN ABOUT 9 PM AND 3 AM WHERE WE COULD SEE
FOG ONCE AGAIN. ONCE THE SURFACE TROUGH MOVES THROUGH...FAIRLY
STRONG NORTHWEST DOWNSLOPING WINDS SHOULD SCOUR OUT FOG/STRATUS
SHORTLY AFTER 06Z OR SO FROM NORTH TO SOUTH.
KEPT POPS GOING FOR OUR EASTERN ZONES WEDNESDAY AS WRAP-AROUND
ENERGY FROM THE DEPARTING LOW IMPACTS THE PANHANDLE AND MAYBE OUR
EXTREME EASTERN COUNTIES.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 235 PM MDT MON AUG 17 2015
A GENERALLY DRY AND MILD/WARM PATTERN EXPECTED TO PREVAIL AVER THE
CWA DURING THE PERIOD. TEMPERATURES WILL TURN WARMER THURSDAY AS
DOWNSLOPE FLOW DEVELOPS IN RESPONSE TO LEE TROFFING SETTING UP
OVER THE HIGH PLAINS. THIS WILL CONTINUE THROUGH FRIDAY AHEAD OF A
DIGGING UPPER TROF THAT WILL MOVE INTO THE NRN ROCKYS FRIDAY
NIGHT. THIS WILL PUSH THE NEXT COOL FRONT ACROSS THE CWA SATURDAY
WITH A BIT OF CONVECTION POSSIBLE WITH IT. EC QUICKER THAN THE GFS
WITH THIS SYSTEM BY ABOUT 12 HOURS WITH COULD IMPACT MAX TEMPS FOR
SATURDAY. SUNDAY AND MONDAY DRY AND SEASONAL WITH A BUILDING
UPPER RIDGE OVER THE ROCKY MTNS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 548 PM MDT MON AUG 17 2015
LIFR CONDITIONS IN STRATUS/FOG WILL REMAIN IN PLACE AT KSNY THIS
EVENING WITH MVFR/IFR AT KAIA AND KBFF IN PERSISTENT MOIST UPSLOPE
FLOW AT THE SFC. LOOKING AT VFR CONDITIONS ELSEWHERE...AT
LEAST UNTIL THE SFC COLD FRONT MOVES SOUTHEAST ACROSS THE AREA
AFTER 03Z. WITH THE COLD FRONT WILL COME WIDESPREAD MAINLY
MVFR/IFR CIGS ACROSS THE AREA ALONG WITH SHOWERS/TSTORMS AND
GUSTY NORTHWEST WINDS. STORM CHANCES SHOULD END FROM NW-SE BY
SUNRISE WITH RAIN SHOWERS POSSIBLE THROUGH TUESDAY MORNING.
CONDITIONS SHOULD IMPROVE THROUGH THIS TIME. WIND GUSTS ARE
EXPECTED TO BE 20 TO 30 KTS FOR MOST SITES THRU MUCH OF TUESDAY.
&&
.FIRE WEATHER...
ISSUED AT 235 PM MDT MON AUG 17 2015
WINDS HAVE BEGUN TO INCREASE OUT ACROSS CARBON COUNTY AND WESTERN
ALBANY COUNTY THIS AFTERNOON. LATEST OBSERVATIONS SHOWING
HUMIDITIES FALLING INTO LOW TEENS AND UPPER SINGLE DIGITS AT 1 PM.
WINDS ARE ON THE INCREASE AS WELL...SO CURRENT FIRE WEATHER
HEADLINES LOOK TO BE ON TRACK. WILL CONTINUE CURRENT RED FLAG
WARNINGS AS THEY ARE AS HEADLINES ARE IN GOOD SHAPE. LOOKING AT
LOW AFTERNOON HUMIDITIES ON A DAILY BASIS WEST OF THE LARAMIE
RANGE THROUGH THE WEEK. FORTUNATELY...WINDS LOOK TO BE WEAK AT
LEAST THROUGH THURSDAY BEFORE ANOTHER LOW PRESSURE SYSTEM
APPROACHES FROM THE WEST. COULD BE LOOKING AT CRITICAL FIRE
WEATHER CONDITIONS FRIDAY INTO SATURDAY AS THIS LOW SLOWLY TRACKS
INTO MONTANA.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR WYZ304-306.
NE...NONE.
&&
$$
SHORT TERM...GCC
LONG TERM...RE
AVIATION...RJM
FIRE WEATHER...GCC
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
319 PM MDT SUN AUG 16 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 254 PM MDT SUN AUG 16 2015
THE LINE OF TSTMS THAT WAS MOVING ACROSS SOUTHERN ALBANY COUNTY HAS
WEAKENED AFTER MOVING INTO LARAMIE COUNTY. SPC MESOANALYSIS SHOWS
QUITE A BIT OF INHIBITION OVER THE PLAINS...AND THIS MAKES SENSE
SINCE IT THE FIRST DAY BEHIND THE FRONTAL PASSAGE. NOT CONFIDENT WE
WILL SEE MUCH MORE STRONG TO SVR STORMS THROUGH THE EARLY EVENING
ESPECIALLY WITH THE LATEST WEAKENING. BOTH THE GFS AND NAM DO SHOW
500-1000 J/KG OF MUCAPE (ELEVATED CAPE) ACROSS THE PLAINS THROUGH
THE NIGHT ALONG WITH GOOD ISENTROPIC LIFT BY LATE TONIGHT SO WILL
KEEP THE MENTION OF TSTMS GOING. THE HIGHEST POPS WILL BE OVER THE
NORTHERN NEBRASKA PANHANDLE. LOW LEVEL RH PROGS AND SOUNDINGS SHOW
QUITE A BIT OF LOW CLOUD COVER ACROSS THE PLAINS BY LATE TONIGHT.
SHORTWAVE TROUGH IS STILL PROGGED TO DROP SOUTHEASTWARD INTO WYOMING
ON MONDAY. A SFC LOW WILL DEVELOP DURING THE AFTN OVER CENTRAL WY
WITH SOUTHEAST WINDS ACROSS THE PLAINS AND BREEZY WEST WINDS TO THE
WEST OF THE LARAMIE RANGE. IT WILL BE QUITE DRY OVER CARBON COUNTY
WITH MIN RH VALUES FALLING TO AROUND 15 PERCENT. THUS ISSUED A FIRE
WEATHER WATCH FOR ZONE 304 (SEE FIRE WEATHER DISCUSSION BELOW). THE
THREAT OF SVR STORMS ACROSS THE PLAINS IS BECOMING MORE OF A
QUESTION MARK. LOW CLOUDS WILL BE QUITE PERSISTENT THROUGH THE
AFTERNOON BUT THE GFS STILL SHOWS SBCAPE VALUES RISING TO AROUND
1500 J/KG IN AREAS NEAR THE COLORADO BORDER. WESTERLY MIDLVL FLOW
ALOFT WILL BE STRONG WITH BULK SHEAR OF 45-50 KTS. SPC MODIFIED THE
DAY 2 OUTLOOK BY DROPPING THE SLIGHT RISK QUITE A BIT FURTHER SOUTH.
LOWERED HIGHS A FEW DEGREES WITH GUIDANCE NOW COMING IN COOLER.
UPPER TROUGH PASSAGE WILL OCCUR ON MON NIGHT WITH THE SFC FROPA BY
TUES MORNING. HAVE HIGH POPS (50-70 PERCENT) OVER THE NORTHEASTERN
PART OF THE CWA ON MON NIGHT WITH LARGE SCALE ASCENT VERY GOOD IN
THE LEFT EXIT REGION OF THE UPPER JET.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 330 PM MDT SUN AUG 16 2015
FRONTAL BOUNDARY GETS PULLED EAST TUESDAY AS UPPER LEVEL LOW
TRACKS INTO CENTRAL SOUTH DAKOTA. COULD BE SEEING SOME FAIRLY
STRONG WINDS TUESDAY AFTERNOON FROM THE NORTHWEST FOR AREAS EAST
OF THE LARAMIE RANGE AS 850MB WINDS ARE FORECAST AT 30-35KTS. SOME
SHOWERS AND THUNDERSTORMS STILL POSSIBLE ACROSS OUR NORTHERN ZONES
TUESDAY AFTERNOON. GFS A LITTLE FASTER BY MAYBE 12 HOURS OR SO
MOVING THE LOW EAST WHILE ECMWF SLOWER...KEEPING POPS OVER THE
AREA THROUGH TUESDAY NIGHT.
AFTER TUESDAY NIGHT/WEDNESDAY MORNING...LOOKS LIKE THE AREA
RETURNS TO DRY WEATHER. NEXT CHANCES FOR SHOWERS APPEARS TO BE
SATURDAY WHEN ANOTHER LOW PRESSURE SYSTEM TRACKS INTO THE NORTHERN
ROCKIES. GOING TO BE FAIRLY COLD TUESDAY WITH HIGHS IN THE 60S
UNDER NORTHEAST UPSLOPING FLOW. AS WINDS TURN MORE WESTERLY...WE
WILL BEGIN TO SEE WARMING TEMPERATURES EACH DAY THROUGH THE WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 254 PM MDT SUN AUG 16 2015
USED LATEST HRRR SYNTHETIC RADAR FOR EARLY TRENDS IN THE FORECAST
FOR OUR AIRPORT FORECASTS. LINE OF THUNDERSTORMS MOVES OVER
CHEYENNE AND INTO THE SOUTHERN PANHANDLE AROUND 00Z. EASTERLY LOW
LEVEL WINDS TO SET UP A FAIRLY WIDESPREAD UPSLOPE EVENT FOR
AIRPORTS EAST OF THE LARAMIE RANGE. CONFIDENCE GROWING THAT THESE
AIRPORTS WILL SEE IFR/LIFR CONDITIONS IN FOG/STRATUS AFTER
08-09Z...PERSISTING INTO LATE MONDAY MORNING.
&&
.FIRE WEATHER...
ISSUED AT 254 PM MDT SUN AUG 16 2015
THE PRESSURE GRADIENT WILL INCREASE ACROSS AREAS TO THE WEST OF THE
LARAMIE RANGE ON MONDAY AFTERNOON CAUSING BREEZY WEST WINDS TO
DEVELOP ESPECIALLY OVER CARBON COUNTY. MINIMUM AFTERNOON HUMIDITY
VALUES WILL DROP TO AROUND 15 PERCENT. THUS CRITICAL FIRE WEATHER
CONDITIONS ARE POSSIBLE AND A FIRE WEATHER WATCH HAS BEEN ISSUED FOR
SOUTHWEST CARBON COUNTY (FIRE WEATHER ZONE 304). MUCH COOLER
TEMPERATURES ARE EXPECTED ON TUESDAY BEHIND A COLD FRONT.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...FIRE WEATHER WATCH FROM MONDAY AFTERNOON THROUGH MONDAY EVENING
FOR WYZ304.
NE...NONE.
&&
$$
SHORT TERM...ZF
LONG TERM...GCC
AVIATION...GCC
FIRE WEATHER...ZF
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1109 AM MDT SUN AUG 16 2015
.UPDATE...
ISSUED AT 1018 AM MDT SUN AUG 16 2015
UPDATED THE FCST TO INCREASE POPS ACROSS SOUTHEAST WY THROUGH THE
AFTERNOON. AN AREA OF SHOWERS AND THUNDERSTORMS IS CURRENTLY
MOVING INTO WESTERN CARBON COUNTY AND WILL CONTINUE MOVING
EASTWARD. THE MODELS SHOW THE BEST INSTABILITY (CAPE VALUES AROUND
1000-1250 J/KG) DEVELOPING FROM THE SOUTHERN LARAMIE RANGE
FOOTHILLS EASTWARD INTO LARAMIE COUNTY BY AROUND 21Z. BULK SHEAR
OF 35-40 KTS WILL SUPPORT A FEW STORMS POTENTIALLY BECOMING SEVERE
THROUGH THE AFTN...MAINLY IN AREAS NEAR INTERSTATE 80.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 315 AM MDT SUN AUG 16 2015
MAIN CONCERNS TODAY AND MONDAY WILL BE FOR SOME SEVERE STORM
POTENTIAL OVER PARTS OF THE CWA IN THE AFTERNOONS AND EARLY
EVENINGS.
CURRENT OBS SEEM TO INDICATE A MODEST COOL FRONT SAGGING SOUTHWARD
ACROSS CENTRAL WY ATTM. EXPECT THIS TO CONTINUE THIS MORNING WITH
THE FRONT BANKING UP AGAINST THE HIGHER TERRAIN BY THIS AFTERNOON.
THIS WILL SET UP AN EASTERLY TO NORTHEASTERLY UPSLOPE FLOW AT THE
SURFACE TOPPED BY WESTERLY UPPER FLOW CREATING A DECENT SHEAR
PATTERN. CAPES THIS AFTERNOON FCST TO BE IN THE 1500-2500 J/KG
RANGE ACROSS THE SRN PANHANDLE INTO FAR SE WY WITH MUCH LESS TO
THE NORTH OF THAT AREA. THIS SHOULD CREATE A DECENT SETUP FOR A
FEW STRONG TO SEVERE STORMS TODAY WITH HAIL AND STRONG WINDS THE
MAIN THREATS. FARTHER TO THE NORTH...CAPPING CREATED BY THE LOW
LEVEL COOLER AIR MASS MAY HINDER ACTIVITY UNTIL LATER THIS EVENING
WHEN AN IMPULSE APPROACHES THE AREA. HIGH TEMPS AROUND 20 DEGREES
COOLER OVER THE PLAINS TODAY. SCTD SHOWERS AND A FEW STORMS MAY
PERSIST OVERNIGHT MAINLY OVER THE PANHANDLE. A SIMILAR PATTERN
SEEN FOR MONDAY WITH DECENT CAPES RETURNING BACK TO MAINLY FAR
SOUTHEAST WY AHEAD OF NEXT UPPER IMPULSE. HIGHER CAPES PROGGED TO
BE MORE OVER EASTERN COLORADO MONDAY AND PRESENCE OF STRATUS AND A
LOW LEVEL INVERSION MAY ACT TO HINDER ACTIVITY OVER THE PLAINS. A
SECONDARY PUSH OF COOLER AIR SHOULD ARRIVE MONDAY NIGHT WITH
RATHER COOL AND SHOWERY CONDITIONS MONDAY NIGHT AND TUESDAY. MAX
TEMPS TUESDAY LIKELY HOLDING IN THE 60S OVER MUCH OF THE PLAINS.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 330 AM MDT SUN AUG 16 2015
THERE IS LITTLE CHANGE IN THE MEDIUM RANGE MODEL CONSENSUS SHOWING
THE NORTH CENTRAL CONUS UPPER TROUGH PROGRESSING EAST ACROSS THE
MS VALLEY THROUGH MIDWEEK. SCATTERED SHOWERS WILL BE ENDING TUESDAY
EVENING AS A DRIER AIR MASS INFILTRATES THE REGION FROM THE NORTHWEST.
THE FLOW ALOFT BACKS TO THE WEST THURSDAY AND SOUTHWEST FRIDAY WITH
THE INFLUENCE OF ANOTHER UPPER TROUGH ENTERING THE PACIFIC NORTHWEST.
THE ECMWF TRACK IS FURTHER SOUTH THAN THE GFS/CANADIAN WITH A CLOSED
LOW MOVING ACROSS MT AND NORTHERN WY FRIDAY NIGHT/SATURDAY. IF THE
ECMWF VERIFIES...MOST OF THE PRECIPITATION WILL OCCUR ACROSS THE
NORTHERN HALF OF WY. MONSOON FLOW WILL BE DIVERTED WELL SOUTH OF
THE CWA UNTIL THE WEEKEND WHEN ISOLATED DIURNAL CONVECTION MAY
RETURN TO THE MOUNTAINS AND SOUTHEAST PLAINS. 700MB TEMPERATURES
WILL BE INCREASING EACH DAY THROUGH FRIDAY...REACHING THE MID TEENS
CELSIUS FRIDAY. HIGHS IN THE 70S WEDNESDAY WILL WARM INTO THE 80S
THURSDAY AND FRIDAY. IT WILL BE BREEZY ALONG AND WEST OF THE
LARAMIE RANGE EACH AFTERNOON WITH GUSTS APPROACHING 25 KT. A COOL
FRONT IS PROGGED TO MOVE THROUGH THE CWA SATURDAY LOWERING HIGH
TEMPERATURES 5 DEGREES OR SO.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1104 AM MDT SUN AUG 16 2015
USED LATEST HRRR SYNTHETIC RADAR FOR EARLY TRENDS IN THE FORECAST
FOR OUR AIRPORT FORECASTS. LINE OF THUNDERSTORMS CURRENTLY OVER
KRWL WILL BEGIN IMPACTING KLAR AROUND 19Z OR SO AND THEN KCYS
AROUND 21Z. COULD BE SEEING SOME LARGE HAIL WITH STORMS BY THE
TIME THEY REACH KCYS. SOUTHERN PANHANDLE AIRPORTS TOWARDS 00Z
AFFECTING KBFF AND KSNY. EASTERLY LOW LEVEL WINDS TO SET UP A
FAIRLY WIDESPREAD UPSLOPE EVENT FOR AIRPORTS EAST OF THE LARAMIE
RANGE. CONFIDENCE GROWING THAT THESE AIRPORTS WILL SEE IFR/LIFR
CONDITIONS IN FOG/STRATUS AFTER 08-09Z...PERSISTING INTO LATE
MONDAY MORNING.
&&
.FIRE WEATHER...
ISSUED AT 315 AM MDT SUN AUG 16 2015
NO CONCERNS SEEN FOR TODAY WITH NON-CRITICAL WEATHER CONDITIONS
EXPECTED...THOUGH THERE WILL BE A LITTLE BREEZINESS OUT WEST THIS
AFTERNOON. SOME CONCERNS ENTER THE PICTURE MONDAY AFTERNOON OVER
FAR WESTERN DISTRICTS AS DRIER AIR MOVES IN ON GUSTY WESTERLY WINDS
WITH MIN RH`S FALLING TO AROUND 15 PERCENT FOR A SHORT TIME MONDAY
AFTERNOON. RIGHT NOW...THE THREAT LOOKS RATHER MARGINAL AND LOCALIZED.
EARLY THIS WEEK SHOULD SEE CONCERNS QUITE LOW WITH COOLER TEMPERATURES
RETURNING ALONG WITH DECENT CHANCES FOR RAINS OVER MOST DISTRICTS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...ZF
SHORT TERM...RE
LONG TERM...MAJ
AVIATION...GCC
FIRE WEATHER...RE
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
549 AM EDT TUE AUG 18 2015
.SYNOPSIS...
AN AREA OF LOW PRESSURE WILL TRACK ACROSS THE CENTRAL PLAINS TODAY
INTO TONIGHT, THEN ACROSS THE UPPER GREAT LAKES REGION WEDNESDAY. AS
THIS LOW MOVES INTO CANADA THURSDAY, ITS ASSOCIATED COLD FRONT IS
FORECAST TO SLOWLY MOVE THROUGH OUR AREA THURSDAY NIGHT AND FRIDAY.
HIGH PRESSURE THEN BUILDS INTO OUR AREA DURING THE WEEKEND, WITH THE
NEXT COLD FRONT ARRIVING LATE MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE GFS INITIALIZATION AT 500MB LOOKED CLOSER THAN THE WRF-NMMB.
AT 850MB, THE INITIALIZATION ERRORS BY BOTH MODELS WERE GENERALLY
1C TOO COLD, WHILE AT 925MB IT WAS A SMATTERING OF 1C ERRORS IN
BOTH DIRECTIONS. ANOTHER NIGHT, A DP/DT IN THE OPPOSITE DIRECTION
AGAIN AS THE MODEL PROGRESSIVE TREND IS SLOWER.
IN THE NEAR TERM ITS A RACE BETWEEN INSTABILITY BEING TAPPED AND
DRIER AIR ARRIVING FROM THE DELMARVA PENINSULA WATERS. COMPLICATING
THE PICTURE FURTHER IS THE SHORT WAVE OVER WEST VIRGINIA AND THE
NEVER SAY DIE TRULY ISOLATED SHOWERS CURRENTLY IN OUR CWA. WHEN ALL
OF THE MEASURABLE VOTES ARE TALLIED THE PAST TWO DAYS, WE WERE VERY
CLOSE TO OUR 15 PCT POP MENTION THRESHOLD ACROSS OUR CWA BOTH DAYS.
BUT OVERALL THERE WAS MORE THAN WHAT WE EXPECTED EVEN IN TERMS OF
ISOLATED PCPN AND THIS SWAYED OUR DECISION FOR TODAY GIVEN WE ARE
IN THE SAME REGIME.
THUS WE ARE BANKING ON A HAT TRICK OF OVERPERFORMANCE VS THE
CONVECTING MESOSCALE MODELS WHICH ONCE AGAIN HAVE NEXT TO NOTHING.
THE SHORT WAVE BANKING AGAINST THE NJ SHORE THAT CAUSED THE
ENHANCED SHOWERS IN PARTS OF THE LOWER RARITAN AND PASSAIC BASINS
IS PREDICTED TO WEAKEN. HRRR HAD A COUPLE OF GOOD RUNS INITIATING
THE PCPN AND IT HAS IT THRU OR DISSIPATED BY 12Z.
THEN IT WOULD APPEAR THE NEXT POTENTIAL ROUND OF ISOLATED
PRECIPITATION SHOULD COMMENCE AROUND NOON TIME. IF PCPN WERE TO
OCCUR IN THE SERN PART OF OUR CWA, HIEST CHANCE WOULD BE THIS
MORNING WHEN MIXED LAYER CAPES ABOVE THE CIN ARE MAXIMIZED. AFTER
THAT ITS ROUGHLY NORTH OF THE PA TURNPIKE AND NORTHWEST OF I287 IN
NJ AS OUR DIVIDING LINE BETWEEN POPS AND NONE AS DRIER AIR ALOFT
ARRIVES.
LATE IN THE DAY, THE ADDED ELEMENT OF THE WESTVA SHORT WAVE BRINGS
POPS INTO DELMARVA. LIKE THE PAST TWO DAYS, PREDICTED BULK SHEAR
VALUES ARE LESS THAN 15 KNOTS. MID LEVEL LAPSE RATES ARE SLIGHTLY
BETTER, AROUND 5.5C/KM, BUT THAT BAR WAS SET VERY LOW ALSO. A REPEAT
OF THE PAST TWO DAYS WITH SLOW MOVING SHOWERS AND TSTMS, ONE OR TWO
OF WHICH MIGHT REQUIRE A FLOOD ADVISORY. STRONG WIND GUSTS AND
SEVERE POTENTIAL ARE MUCH LOWER THAN AVERAGE FOR AN AUGUST AFTERNOON
WITH TSTMS AROUND.
TEMPERATURES, ANOTHER DAY OF 90S FOR A CHUNK OF OUR CWA. BUT, THE
AIR MASS IS SLIGHTLY COOLER AND IN QUOTES COOLER AIR IS WRAPPING
AROUND THE OFFSHORE HIGH INTO OUR AREA. IN ADDITION, THE SKY WILL
NOT BE AS CLEAN WITH UPSTREAM CIRRUS HEADING OUR WAY AND ALTOCU
AROUND EARLY THIS MORNING. THE GFS PREDICTED 850MB TEMP DROP THIS
AFTERNOON HAS NO UPSTREAM HISTORY. IN GENERAL MAX TEMPS HAVE BEEN
AVERAGING AROUND 2F HIGHER THAN STAT GUIDANCE THE PAST COUPLE OF
DAYS AND WE USED THIS FORMULA AGAIN TODAY.
MAX TEMPS ABOUT A DEGREE OR TWO COOLER THAN YESTERDAY COUPLED WITH
SIMILAR TO SLIGHTLY HIGHER DEW POINTS SHOULD RESULT IN HEAT INDEX
VALUES VERY SIMILAR TO YESTERDAY, PEAKING IN THE MID 90S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
THE SHORT WAVES HAVE TO RUN THEIR COURSE OVERNIGHT. WITH THE RIDGE
AXIS GONE, THERE IS NOTHING TO IMPEDE THEIR MOTION INTO OUR CWA.
THE WEAKENING TREND LOOKS REASONABLE GIVEN THAT INSTABILITY IS NOT
PREDICTED TO INCREASE OVERNIGHT. STILL A PAIR OF SHORT WAVES, THE
ONE IN WEST VIRGINIA AND A SECOND FARTHER WEST IN THE OHIO VALLEY
SHOULD KEEP SOME LOW CHANCE OF SHOWERS AND TSTMS GOING FOR MOST OF
THE NIGHT.
THE MOISTENING TREND CONTINUING WITH THE SOUTHEAST TO SOUTH FLOW AND
MODEL SOUNDINGS ARE SUGGESTING LOW CLOUDS MAY FORM OVERNIGHT. THIS
SHOULD KEEP MIN TEMPS RELATIVELY HIGHER. THE INCREASING DEW POINTS
WILL LIKELY ACCOMPLISH THAT WHETHER THE CLOUDS FORM OR NOT. MINS NOT
THAT FAR FROM STAT GUIDANCE.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
THE SYNOPTIC SETUP IS COMPRISED OF AN UPPER-LEVEL RIDGE THAT HANGS
ON FOR AWHILE IN THE WESTERN ATLANTIC TOWARD THE CANADIAN MARITIMES,
MEANWHILE A STRONG UPPER-LEVEL TROUGH/CLOSED LOW MOVES ACROSS THE
NORTHERN PLAINS TO THE GREAT LAKES WEDNESDAY. THIS FEATURE LOOKS TO
BE DEFLECTED INTO CANADA AS THE UPPER-LEVEL RIDGE HOLDS INTO THE
CANADIAN MARITIMES. THE RIDGE IS FORECAST TO GRADUALLY WEAKEN WITH A
BROAD TROUGH FROM THE PLAINS TO THE GREAT LAKES. THIS MAY THEN
AMPLIFY FROM THE MIDWEST AND GREAT LAKES OVER THE WEEKEND, WHICH
DRIVES A COLD FRONT INTO OUR AREA LATE MONDAY. A SLOW MOVING COLD
FRONT HOWEVER LATE THURSDAY AND FRIDAY MAY RESULT IN LOCALLY HEAVY
RAIN GIVEN PW VALUES SURGING TO AROUND 2 INCHES. WE USED A MODEL
BLEND FOR WEDNESDAY INTO FRIDAY, THEN BLENDED IN THE 00Z WPC GUIDANCE
WITH CONTINUITY.
FOR WEDNESDAY...HIGH PRESSURE TO OUR EAST WILL MAINTAIN A SOUTHERLY
FLOW OF WARM AND MOIST AIR ACROSS THE AREA. AN UPPER-LEVEL TROUGH
CLOSING OFF IN THE MIDWEST TO THE UPPER GREAT LAKES WILL DRIVE A
COLD FRONT EASTWARD. A WEAK WARM FRONT COMBINED WITH SOME LIFT MAY
RESULT IN SOME CONVECTION ESPECIALLY FOR THE INLAND AREAS. THE
COVERAGE DOES NOT APPEAR TO BE MUCH WITH MOST OF THE BETTER LIFT
REMAINING TO OUR WEST. THEREFORE, WE KEPT SLIGHT CHC TO LOW CHC POPS
IN FOR THE IDEA OF ISOLATED TO SCATTERED CONVECTION DEVELOPING. MORE
CLOUDINESS AND A SOUTHEASTERLY LOW-LEVEL FLOW SHOULD RESULT IN SOME
COOLING, HOWEVER IT WILL BE HUMID.
FOR THURSDAY AND FRIDAY...A CLOSED LOW IS FORECAST TO MOVE INTO
CANADA AS RIDGING HOLDS INTO THE CANADIAN MARITIMES. THIS WILL TAKE
THE SURFACE LOW WELL TO OUR NORTHWEST WITH ITS ASSOCIATED COLD FRONT
SLOWLY MOVING THROUGH THURSDAY NIGHT AND FRIDAY. THERE IS PLENTY OF
MOISTURE IN PLACE WITH PW VALUES SURGING TO AROUND 2 INCHES, HOWEVER
THE BULK OF THE LARGE SCALE LIFT IS FORECAST TO BE REMOVED FROM OUR
AREA DUE TO THE UPPER-LEVEL SYSTEM TRACKING SO FAR TO OUR WEST AND
NORTH.
A CYCLONICALLY CURVED 500 MB JET IS FORECAST TO LIFT UP THE OHIO
VALLEY AND ACROSS WESTERN/CENTRAL NEW YORK AND PENNSYLVANIA. THIS
PLACES OUR WESTERN ZONES CLOSE TO THE ENTRANCE REGION FOR A TIME
LATE THURSDAY INTO FRIDAY MORNING. THIS TIMING MAY CHANGE THOUGH
DEPENDING ON THE ACTUAL SPEED OF THE ENTIRE SYSTEM. AS A RESULT,
SOME ENHANCED LIFT MAY GLANCE OUR AREA INTO FRIDAY WITH A LINE OR
BROKEN LINE OF HEAVY RAIN PRODUCING CONVECTION POTENTIALLY AIDED BY
A FRONTAL CONVERGENCE ZONE. THE LOW-LEVEL FLOW IS FROM THE SOUTHEAST
BUT GENERALLY ON THE LIGHTER SIDE, WHICH COULD FAVOR SOME
BACKBUILDING/TRAINING CONVECTION WITHIN AN ENVIRONMENT CHARACTERIZED
BY A TALL AND THIN CAPE PROFILE. THE DETAILS ARE NOT ALL THAT CLEAR
THOUGH AS WE HAVE SOME CONCERN THE CONVECTION COULD BE MORE LIMITED
GIVEN THE MAIN DYNAMICS PASSING WELL TO OUR WEST AND NORTH. HOWEVER,
THERE STILL REMAINS THE POTENTIAL FOR INCREASING CONVECTIVE COVERAGE
WITH LOCALLY VERY HEAVY RAINFALL. A MENTION WILL REMAIN IN THE
HAZARDOUS WEATHER OUTLOOK.
FOR SATURDAY AND SUNDAY...A COLD FRONT SHOULD BE JUST OFFSHORE TO
START SATURDAY WITH THE FRONT POSSIBLY STALLING AS THE PARENT UPPER-
LEVEL TROUGH LIFTS WELL UP INTO CANADA. THIS ALLOWS SURFACE HIGH
PRESSURE TO BUILD INTO THE AREA, ALTHOUGH IT SHOULD WEAKEN SOME
DURING SUNDAY AS IT STARTS TO SHIFT OFFSHORE. SINCE WE ARE REMOVED
FROM THE AFOREMENTIONED MAIN UPPER-LEVEL TROUGH BUT THE SURFACE
FRONT EASES OFFSHORE, WE HAVE SOME SLIGHT CHC TO LOW CHC POPS ACROSS
THE EAST SATURDAY, THEN SLIGHT CHC EVERYWHERE ON SUNDAY. OVERALL,
THE WEEKEND FOR MOST ATTM LOOKS TO BE DRY. A COOLER AIRMASS IS
EXPECTED TO SETTLE IN FOLLOWING THE FRONTAL PASSAGE, WITH SOME
LOWERING OF THE DEW POINTS ESPECIALLY THE FARTHER INLAND ONE GOES.
FOR MONDAY...ANOTHER AMPLIFYING UPPER-LEVEL TROUGH IS FORECAST TO
CRUISE ACROSS THE NORTHERN PLAINS TO THE GREAT LAKES. THIS WILL
DRIVE LOW PRESSURE MAINLY NORTH OF THE GREAT LAKES, AND ITS
ASSOCIATED COLD FRONT ARRIVES IN OUR AREA LATE. SOME CONVECTION
SHOULD ACCOMPANY THE FRONT, HOWEVER ONCE AGAIN THE MAIN FORCING WITH
THE PARENT UPPER-LEVEL TROUGH MAY END UP BEING REMOVED FROM OUR
AREA. THIS MAY LIMIT THE CONVECTIVE CHCS FOR OUR AREA AS A RESULT.
&&
.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
OTHER THAN SOME MVFR CONDITIONS AT MORE RURAL AIRPORTS AND
TERMINALS AROUND SUNRISE, 06Z TAFS ARE VFR.
THROUGH 12Z TODAY...A FEW LEFTOVER MID LEVEL CLOUDS (MAINLY
BEFORE SUNRISE) AND CIRRUS ABOVE THEM. WINDS WILL BE LIGHT
FROM THE SOUTH TO SOUTHEAST. SOME MVFR FOG POSSIBLE AT MORE
RURAL TERMINALS AND AIRPORTS WHERE PCPN OCCURRED ON MONDAY. WE
MADE SLIGHT ADJUSTMENTS TO FOG IN THE TAFS BASED ON HOW WIDE THE
CURRENT TEMPERATURE AND DEW POINT SPREADS ARE.
THIS MORNING...ANY FOG SHOULD BE GONE. VFR WITH A SOUTH WIND
INCREASING TO 5 TO 10 KNOTS. FEW TO SCATTERED CUMULUS AT 5K TO 6K
SHOULD START FORMING.
THIS AFTERNOON INTO EARLY EVENING...FEW TO SCATTERED CUMULUS
CONTINUING WITH CIRRUS ABOVE. SOUTH TO SOUTHEAST WINDS AVERAGING
CLOSER TO 10 KNOTS. LIKE THE PAST TWO DAYS, WIDELY SCATTERED
SHWRS AND TSTMS ARE EXPECTED TO DEVELOP, BUT CONFIDENCE ABOUT THEM
AFFECTING ANY OF THE TERMINALS IS LOW AND NOT INCLUDED. GREATEST
COVERAGE SHOULD BE AT NORTHWEST AIRPORTS.
OVERNIGHT...ONE OF OUR GUIDANCE MODELS IS PREDICTING IFR CIGS TO
FORM AT THE TERMINALS. MOST OTHER GUIDANCE INCLUDING SOME OF THE
NEWER EXPERIMENTAL MODELS WE ARE VIEWING STILL DO NOT. IFR CIGS
ARE PREDICTED NORTH OF KABE AND KTTN.
INITIAL THOUGHT FOR 12Z TAFS IS TO FOLLOW IDEA OF LOWEST (MVFR) CIGS
AT THE TERMINALS WITH THE MOST UPSLOPE/SOUTH FLOW (KABE, KRDG AND
KTTN). OTHER TERMINALS, WE KEPT CIGS MAINLY AT VFR LEVELS.
FARTHER UPSLOPE AIRPORTS IN THE POCONOS AND NORTHWEST NEW JERSEY
MIGHT HAVE IFR CIGS. CONFIDENCE ABOUT IFR CIG OCCURRING AT THE
TERMINALS AND KPHL IS LOW. WE WILL ALSO BRING IN SOME LIGHT FOG
(MVFR RESTRICTIONS) TO MOST NON URBAN TERMINALS BY WEDNESDAY
MORNING. SOUTHEAST WINDS SHOULD AVERAGE 5 KNOTS OR LESS.
OUTLOOK...
WEDNESDAY...VFR OVERALL. THERE COULD BE SOME MVFR/IFR CONDITIONS TO
START DUE TO LOW CLOUDS OR FOG, THEN POSSIBLY LOCALLY AGAIN THROUGH
THE DAY AND EVENING WITH A FEW SHOWERS OR THUNDERSTORMS.
THURSDAY AND FRIDAY...SHOWERS AND THUNDERSTORMS MAY BECOME NUMEROUS
FOR A TIME WITH A SLOW MOVING COLD FRONT. THIS WILL RESULT IN TIMES
OF MVFR/IFR CONDITIONS. A WIND SHIFT TO THE NORTHWEST SHOULD OCCUR
WITH THE PASSAGE OF A COLD FRONT THURSDAY NIGHT AND FRIDAY.
SATURDAY...VFR OVERALL AS HIGH PRESSURE BUILDS IN.
&&
.MARINE...
SUB SMALL CRAFT ADVISORY CONDITIONS ARE PREDICTED TO CONTINUE TODAY
AND TONIGHT. HOWEVER, A STRONGER SOUTHERLY GRADIENT (BECOMING SE
IN DELAWARE BAY) WILL BRING WIND GUSTS TO AROUND 20 KNOTS LATER THIS
AFTERNOON INTO EVENING BEFORE DECREASING AGAIN. WAVE WATCH GUIDANCE
WHICH NORMALLY IS QUITE BULLISH WITH SOUTHERLY FLOW SEAS REMAINS
SUBDUED WITH SUB SMALL CRAFT ADVISORY SEAS.
OUTLOOK...
WEDNESDAY THROUGH FRIDAY...THE WINDS AND SEAS ARE ANTICIPATED TO
REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA AS A COLD FRONT SLOWLY
CROSSES THE AREA. A FEW THUNDERSTORMS COULD PRODUCE A LOCALLY STRONG
WIND GUST MAINLY LATE THURSDAY AND FRIDAY. THE PASSAGE OF THE COLD
FRONT FRIDAY SHOULD RESULT IN THE WINDS SHIFTING TO NORTHERLY.
SATURDAY...THE WINDS AND SEAS SHOULD REMAIN BELOW SMALL CRAFT
ADVISORY CRITERIA AS HIGH PRESSURE BUILDS IN FROM THE NORTHWEST.
&&
.RIP CURRENTS...
THE IN HOUSE OFFICE REGRESSION EQUATION FOR RIP CURRENT RISKS
CAME UP WITH MODERATE FOR TODAY ALONG THE NJ COAST AND LOW FOR
THE DELAWARE COAST. GIVEN THAT WINDS TODAY ARE EXPECTED TO BE
SLIGHTLY STRONGER AND MORE FROM THE SOUTHEAST, WE WILL USE THIS
RESULT VS THE GFE OUTPUT WHICH WAS LOW ACROSS THE BOARD.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GORSE
NEAR TERM...GIGI
SHORT TERM...GIGI
LONG TERM...GORSE
AVIATION...GIGI/GORSE
MARINE...GIGI/GORSE
RIP CURRENTS...
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
247 AM CDT TUE AUG 18 2015
.UPDATE...
THUNDERSTORMS CONTINUE TO FIRE THIS EVENING ALONG VARIOUS
BOUNDARIES. THE MAIN BOUNDARY EXTENDS FROM CENTRAL COOK COUNTY
THROUGH SOUTHERN DUPAGE INTO NORTHERN KENDALL. LATEST RAP
ANALYSIS INDICATES WE HAVE AROUND 500 J/KG OF CAPE TO WORK WITH
ALONG THE BOUNDARY SO ADDITIONAL ISOLATED TO SCATTERED STORMS ARE
POSSIBLE. THIS IS ESPECIALLY TRUE AS THE CURRENT STORMS PRODUCE
THEIR OWN BOUNDARIES. WITH LONG SKINNY CAPE VALUES IN FORECAST AND
00Z SOUNDINGS...EXPECTING ONLY THE STRONGEST STORMS TO PRODUCE
WIND GUSTS UP TO 50-60 MPH AND SMALL HAIL. ALL STORMS HOWEVER WILL
PRODUCE TORRENTIAL RAINFALL. THUS FAR MOST OF THE STORMS HAVE
EITHER BEEN MOVING OR WEAKENING JUST FAST ENOUGH TO AVOID FLOODING
ISSUES...BUT WILL CONTINUE TO MONITOR FOR TRAINING STORMS THAT
COULD PRODUCE FLASH FLOODING AND STANDING WATER.
STILL HAVE LOW CONFIDENCE IN EXACTLY HOW THE REST OF THE EVENING
WILL PROGRESS IN REGARDS TO STORMS. THE HRRR HAS DONE A VERY GOOD
JOB AT CAPTURING MOST OF WHAT HAS HAPPENED THUS FAR SO POP
FORECAST IS MOSTLY BASED OFF OF IT. EXPECTING MORE SCATTERED PULSE
CONVECTION ALONG THE OUTFLOW BOUNDARIES WHILE THE AREA OF
CONVECTION OVER WESTERN IL SPREADS EAST. THINKING THE STORMS OVER
WESTERN IL WILL WEAKEN AS THEY SHIFT EAST...BUT MORE STORMS WILL
PROBABLY FORM ALONG ANY OUTFLOW BOUNDARIES THE ORIGINAL STORMS
PRODUCE. IN ADDITION..A SHORTWAVE TROUGH IS OVER EASTERN IOWA SO
THINKING THAT WILL HELP FORCE WAVES OF CONVECTION THROUGH THE
NIGHT. HAD A VERY DIFFICULT TIME BEING MORE DETERMINISTIC IN MY
FORECAST SIMPLY BECAUSE OF THE MESOSCALE NATURE OF THE STORMS.
THEREFORE HAVE HIGH CONFIDENCE IN SCATTERED STORMS MAINLY
NORTHWEST OF A DE MOTTE THROUGH GIBSON CITY LINE...BUT LOW
CONFIDENCE IN EXACT TIMING AND COVERAGE AT ANY GIVEN TIME.
WITH THE AMPLE MOISTURE FROM THE STORMS...KEPT PATCHY FOG GOING
AFTER MIDNIGHT.
JEE
&&
.SHORT TERM...
340 PM CDT
THROUGH TUESDAY...
SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE THIS AFTERNOON. SEVERAL
OF THE STRONGER STORMS HAVE REPORTED WIND GUSTS AROUND 50 MPH AND
SMALL HAIL...ALONG WITH MODERATE TO HEAVY DOWNPOURS AND LIKELY
LOCALLY 1 INCH PLUS RAINFALL TOTALS.
THIS ACTIVITY IS COURTESY OF SEVERAL FEATURES...THE FIRST AN UPPER
LEVEL DISTURBANCE PUSHING INTO CENTRAL INDIANA WITH A WELL DEFINED
CLOSED CIRCULATION ON WATER VAPOR SATELLITE IMAGERY. THE SECOND IS A
COLD FRONT STRETCHED SOUTHWEST FROM NORTHERN LAKE MICHIGAN...THROUGH
CENTRAL WISCONSIN...THEN ORIENTED WEST-EAST IN MOST OF IOWA. SPC
MESOANALYSIS SHOWS MODERATE INSTABILITY WITH GOOD LOW LEVEL LAPSE
RATES...BUT POOR SHEAR...AND MODEST PW VALUES. THEREFORE LOCALLY
HEAVY RAINFALL AND GUSTY WINDS WILL REMAIN THE PREDOMINANT HAZARDS
THROUGH THE AFTERNOON AND EARLY EVENING HOURS. THESE STORMS ARE
PRODUCING OUTFLOW BOUNDARIES THAT WILL LOCALLY INCREASE
CONVERGENCE SUGGESTING SCATTERED STORMS REMAIN POSSIBLE AREA-WIDE.
WHILE THE CONVECTIVE EVOLUTION IS STILL A BIT UNCERTAIN...EXPECT A
DIURNAL DECREASE IN THE COVERAGE AWAY FROM THE COLD FRONT AS THE
UPPER LEVEL LOW ENTERS INDIANA EXITS TO THE EAST...ESPECIALLY INTO
EASTERN ILLINOIS AND NORTHWEST INDIANA. ADDITIONALLY...MODEL
GUIDANCE STALLS THE FRONT OUT ALONG A DUBUQUE TO ROCKFORD TO
MILWAUKEE LINE. THE NEXT SET OF DISTURBANCES PROPAGATE PARALLEL TO
THE COLD FRONTAL BOUNDARY...THUS HAVE RETAINED HIGHEST POPS IN NORTH
CENTRAL ILLINOIS AND ALONG THE WISCONSIN BORDER. A TRAILING
DISTURBANCE IN WESTERN IOWA WILL MOVE THROUGH THE AREA OVERNIGHT
WHICH MAY ALLOW SOME FURTHER EASTWARD PROGRESSION OVERNIGHT.
HEIGHT RISES AND SUBSIDENCE IN WAKE OF THE DEPARTING DISTURBANCE BUT
BROAD SW MOIST LOWER LEVEL FLOW SUPPORTS LOWER POPS BUT A QUIETER
PERIOD IN GENERAL. A STRONG UPPER LEVEL LOW WILL BE WORKING EASTWARD
THROUGH THE CENTRAL PLAINS ON TUESDAY. WHILE THE STRONGEST STORMS
APPEAR TO BE IN IOWA...SOME MAY SNEAK INTO OUR AREA AS WELL LATER IN
THE DAY...BUT MORE LIKELY IN THE EVENING. WEAK INSTABILITY WILL BE
PRESENT DURING THE DAY COUPLED WITH INCREASING SHEAR AND MAY SUPPORT
SCATTERED DEVELOPMENT AGAIN DURING THE AFTERNOON.
KMD
&&
.LONG TERM...
310 PM CDT
TUESDAY NIGHT THROUGH THURSDAY...
THE PERIOD WILL BEGIN FAIRLY ACTIVE AS A NOW CLOSED UPPER LEVEL
SYSTEM CONTINUES TO SLOWLY PROGRESS EAST THROUGH THE NORTHERN
PLAINS AND UPPER MIDWEST. GUIDANCE IN FAIR AGREEMENT WITH OVERALL
EVOLUTION/PLACEMENT OF THIS SYSTEM AS WELL SEVERAL IMPULSES
LIFTING NORTHEAST ACROSS THE CWA/REGION...WHILE SURFACE LOW AND
BOUNDARY REMAIN WELL TO THE NORTHWEST AND WEST DURING THIS TIME.
ALTHOUGH PLACEMENT OF STRONGER AND MORE WIDESPREAD THUNDERSTORM
DEVELOPMENT WILL INITIALLY BE SITUATED WEST OF THE
CWA...INCREASING MOISTURE AND INSTABILITY OUT AHEAD OF THIS SYSTEM
TUESDAY/TUESDAY NIGHT WHILE PERSISTENT FORCING IS PRESENT COULD
ALLOW FOR SCATTERED DEVELOPMENT ACROSS THE CWA. FOCUS WILL THEN
SHIFT TOWARDS MORE WIDESPREAD DEVELOPMENT APPROACHING OUT AHEAD OF
EASTWARD MOVING FRONTAL BOUNDARY OVER IOWA. THESE
THUNDERSTORMS...DEVELOPING THROUGHOUT THE DAY TUESDAY...WILL BE
APPROACHING THE CWA BY THE MID TO LATE EVENING TIME FRAME. WITH
PERSISTENT FORCING THROUGHOUT THE NIGHT...WOULD EXPECT SHOWERS AND
THUNDERSTORMS TO BE POSSIBLE OVER MUCH OF THE CWA. ALTHOUGH
CONFIDENCE IS HIGHER WITH COVERAGE...CONFIDENCE IS LOWER WITH
REGARD TO INTENSITY OF THESE STORMS. QUESTIONS AS TO HOW MUCH THE
ATMOSPHERE WILL DESTABILIZE ON TUESDAY WILL PLAY A FACTOR WITH
INTENSITY MAINTAINING ITSELF WEDNESDAY EVENING. DO THINK AT LEAST
A FEW/ISOLATED STRONGER STORMS WILL BE POSSIBLE...BUT WILL NEED TO
MONITOR FOR POSSIBLE HIGHER COVERAGE OF THESE STRONGER STORMS.
WHILE FRONTAL BOUNDARY WILL CONTINUE TO PUSH EAST WEDNESDAY
MORNING...THUNDERSTORM CHANCES WILL BE ENDING FROM WEST TO EAST
WITH THE ARRIVAL OF MUCH DRIER AIR ON BACKSIDE OF THIS SYSTEM.
HOWEVER...THERE IS SOME VARIABILITY WITH HOW QUICKLY THIS FRONT
PUSHES THROUGH. WITH THIS SYSTEM CLOSING ITSELF OFF...I AM A
LITTLE CONCERNED THAT A MORE PREFERRED SOLUTION WOULD BE FOR A
SLOWER TIME FRAME. IF THIS WERE TO OCCUR...THEN THERE WOULD BE AN
ADDITIONAL CHANCE FOR STRONG TO SEVERE THUNDERSTORMS ACROSS THE
EASTERN CWA WEDNESDAY AS MOISTURE/INSTABILITY WOULD CONTINUE TO
STREAM NORTHWARD OUT AHEAD OF IT. HOWEVER...WOULD THINK ALREADY
PRESENT CLOUD COVER AND PRECIP WOULD LIMIT HOW UNSTABLE THE CWA
WOULD BE...WITH BETTER INSTABILITY LIKELY STAYING EAST OF THE CWA.
THUNDERSTORM CHANCES WILL LIKELY DIMINISH FROM WEST TO EAST IN THE
AFTERNOON AND ALTHOUGH PRECIP CHANCES MAY LINGER IN THE
EVENING...THUNDER SHOULD STAY TO THE EAST. HIGH TEMPERATURES ON
WEDNESDAY WILL LIKELY OCCUR EARLY IN THE DAY WEDNESDAY AND WHILE
STRONGER WESTERLY WINDS INCREASE INTO THE AFTERNOON. DESPITE SOME
TIMING DIFFERENCE WITH THE EVOLUTION OF THIS LARGE SYSTEM...WITH
DRIER AIR WORKING IN AND BETTER FORCING EXITING...THURSDAY IS
APPEARING TO BE DRY.
RODRIGUEZ
THURSDAY NIGHT THROUGH MONDAY
THE MAIN POINT OF INTEREST FOR THE REST OF THIS WEEK AND INTO THE
WEEKEND IS AN UPPER LEVEL DISTURBANCE AND ASSOCIATED SFC LOW.
WATER VAPOR SATELLITE SHOWS A MID-LEVEL TROUGH DEVELOPING OVER THE
DAKOTAS THAT WILL PROGRESS EAST THROUGH THE UPPER GREAT LAKES
REGION THE NEXT COUPLE OF DAYS. BOTH NAM AND GFS GUIDANCE ARE IN
RATHER GOOD AGREEMENT WITH THE TIMING AND INTENSITY OF THIS
DISTURBANCE. THIS TAKES THE CENTER OF THE LOW NORTH OF THE CWA
THROUGH MN AND WI. POPS ARE PROBABLE WITH THIS SETUP WITH EMBEDDED
WAVES WITHIN THE TROUGH, HOWEVER THERE IS UNCERTAINTY AS TO THE
AMOUNT OF POPS THE AREA WILL SEE WITH THIS DISTURBANCE. SATURDAY
LOOKS TO BE THE FAVORABLE DAY FOR CONVECTION WITH AN ISOLATED
THUNDERSTORM. COVERAGE OF TSRA WILL LIKELY BE SMALL. EXPECT TEMPS
TO DROP WITH FROPA BUT RECOVER BACK INTO THE 80S WITH SWLY FLOW AT
THE SFC. DEWPOINTS LOOK TO STAY PUT IN THE LOWER TO MID 60S. THE
SFC LOW WILL LEAD TO DEVELOPMENT OF STRONG PRESSURE GRADIENT
FAVORING STRONG WIND GUSTS AS THIS DISTURBANCE PROGRESSES ACROSS
THE REGION.
KRULL
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* PERIODIC CHANCES FOR THUNDERSTORMS.
* CHANCE FOR FOG OR LOW CIGS TUESDAY MORNING.
BMD
//DISCUSSION...UPDATED 06Z...
SCATTERED SHOWERS AND THUNDERSTORMS ARE IN PLACE ACROSS NORTHERN
ILLINOIS LATE THIS EVENING AND WILL CONTINUE THOUGH SOME OF THE
OVERNIGHT HOURS...THOUGH DO EXPECT A GENERAL DIMINISHING TREND IN
THE INTENSITY AND COVERAGE AS FORCING BEGINS TO EXIT EAST AND
INSTABILITY CONTINUES TO WANE NOCTURNALLY. WILL HAVE TO MONITOR
THE THREAT FOR LOW CIGS OR FOG DEVELOPING OVERNIGHT...ESPECIALLY
IF THERE IS PARTIAL CLEARING WHICH WILL ALLOW RADIATIVE COOLING
GIVEN LIGHT WINDS.
DURING THE DAY TUESDAY...INSTABILITY QUICKLY BUILDS THROUGH THE
MORNING WITH FORECAST SOUNDINGS SHOWING UNCAPPED PARCELS BY LATE
MORNING AND EARLY AFTERNOON. WOULDNT BE SURPRISED TO SEE A FEW
POP UPS HOWEVER TRANSIENT UPPER LEVEL RIDGING SHOULD SUPPRESS ANY
MORE WIDESPREAD CONVECTION EARLY IN THE DAY. BY MID AFTERNOON
HOWEVER... MID LEVEL HEIGHT FALLS BEGIN TO OVERSPREAD THE REGION
AHEAD OF A POTENT SYSTEM LIFTING ACROSS THE PLAINS. THE FOCUS
TOMORROW AFTERNOON AND EVENING SHOULD BE ALONG AND WEST OF THE
MISSISSIPPI RIVER HOWEVER GIVEN THE INSTABILITY AND BROAD SCALE
ASCENT CANNOT RULE OUT ISOLATED ACTIVITY NEAR THE
TERMINALS...ESPECIALLY RFD. EXPECT THUNDERSTORMS TO MOVE INTO
NORTHERN ILLINOIS LATE EVENING INTO THE EARLY OVERNIGHT HOURS.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE IN WIND TRENDS.
* LOW-MEDIUM CONFIDENCE IN TSRA/SHRA TIMING.
* LOW CONFIDENCE IN CIG/VSBY TRENDS EARLY TUESDAY MORNING.
BMD
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
* WEDNESDAY...CHANCE OF TSRA. STRONG/GUSTY SOUTHWEST WINDS.
* THURSDAY...DRY/VFR. STRONG/GUSTY WESTERLY WINDS.
* FRIDAY...DRY/VFR. SOUTH/SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. SOUTH/SOUTHEAST WINDS.
* SUNDAY...CHANCE OF TSRA. SOUTHWEST WINDS.
&&
.MARINE...
247 AM CDT
A QUASI STATIONARY FRONTAL BOUNDARY IS DRAPED ACROSS CENTRAL LAKE
MICHIGAN EARLY THIS MORNING BUT IS EXPECTED TO BEGIN LIFTING
NORTH TODAY AS AN UNSEASONABLY STRONG SYSTEM DEVELOPS OVER THE
CENTRAL PLAINS AND DEEPENS AS IT LIFTS ACROSS WISCONSIN LATE THIS
EVENING AND INTO ONTARIO ON WEDNESDAY. SOUTH WINDS RAMP UP ACROSS
THE LAKE TONIGHT INCREASING INTO THE 20 TO 30 KT RANGE AND
CONTINUE THROUGH THE DAY WEDNESDAY VEERING TO THE SOUTHWEST.
WEDNESDAY NIGHT THE COLD FRONT WILL SWEEP ACROSS THE LAKE WITH
WINDS TURNING WESTERLY AND STAYING PROPPED UP AROUND 30 KT. CANNOT
RULE OUT A WINDOW OF GALES AT THIS TIME. WINDS SHOULD TAPER SOME
THROUGH THE DAY THURSDAY. ANOTHER STRONG LOW IS POSSIBLE OVER THE
WEEKEND DRAGGING A COLD FRONT ACROSS LAKE MICHIGAN ON SUNDAY.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1246 AM CDT TUE AUG 18 2015
.UPDATE...847 PM CDT
THUNDERSTORMS CONTINUE TO FIRE THIS EVENING ALONG VARIOUS
BOUNDARIES. THE MAIN BOUNDARY EXTENDS FROM CENTRAL COOK COUNTY
THROUGH SOUTHERN DUPAGE INTO NORTHERN KENDALL. LATEST RAP
ANALYSIS INDICATES WE HAVE AROUND 500 J/KG OF CAPE TO WORK WITH
ALONG THE BOUNDARY SO ADDITIONAL ISOLATED TO SCATTERED STORMS ARE
POSSIBLE. THIS IS ESPECIALLY TRUE AS THE CURRENT STORMS PRODUCE
THEIR OWN BOUNDARIES. WITH LONG SKINNY CAPE VALUES IN FORECAST AND
00Z SOUNDINGS...EXPECTING ONLY THE STRONGEST STORMS TO PRODUCE
WIND GUSTS UP TO 50-60 MPH AND SMALL HAIL. ALL STORMS HOWEVER WILL
PRODUCE TORRENTIAL RAINFALL. THUS FAR MOST OF THE STORMS HAVE
EITHER BEEN MOVING OR WEAKENING JUST FAST ENOUGH TO AVOID FLOODING
ISSUES...BUT WILL CONTINUE TO MONITOR FOR TRAINING STORMS THAT
COULD PRODUCE FLASH FLOODING AND STANDING WATER.
STILL HAVE LOW CONFIDENCE IN EXACTLY HOW THE REST OF THE EVENING
WILL PROGRESS IN REGARDS TO STORMS. THE HRRR HAS DONE A VERY GOOD
JOB AT CAPTURING MOST OF WHAT HAS HAPPENED THUS FAR SO POP
FORECAST IS MOSTLY BASED OFF OF IT. EXPECTING MORE SCATTERED PULSE
CONVECTION ALONG THE OUTFLOW BOUNDARIES WHILE THE AREA OF
CONVECTION OVER WESTERN IL SPREADS EAST. THINKING THE STORMS OVER
WESTERN IL WILL WEAKEN AS THEY SHIFT EAST...BUT MORE STORMS WILL
PROBABLY FORM ALONG ANY OUTFLOW BOUNDARIES THE ORIGINAL STORMS
PRODUCE. IN ADDITION..A SHORTWAVE TROUGH IS OVER EASTERN IOWA SO
THINKING THAT WILL HELP FORCE WAVES OF CONVECTION THROUGH THE
NIGHT. HAD A VERY DIFFICULT TIME BEING MORE DETERMINISTIC IN MY
FORECAST SIMPLY BECAUSE OF THE MESOSCALE NATURE OF THE STORMS.
THEREFORE HAVE HIGH CONFIDENCE IN SCATTERED STORMS MAINLY
NORTHWEST OF A DE MOTTE THROUGH GIBSON CITY LINE...BUT LOW
CONFIDENCE IN EXACT TIMING AND COVERAGE AT ANY GIVEN TIME.
WITH THE AMPLE MOISTURE FROM THE STORMS...KEPT PATCHY FOG GOING
AFTER MIDNIGHT.
JEE
&&
.SHORT TERM...
340 PM CDT
THROUGH TUESDAY...
SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE THIS AFTERNOON. SEVERAL
OF THE STRONGER STORMS HAVE REPORTED WIND GUSTS AROUND 50 MPH AND
SMALL HAIL...ALONG WITH MODERATE TO HEAVY DOWNPOURS AND LIKELY
LOCALLY 1 INCH PLUS RAINFALL TOTALS.
THIS ACTIVITY IS COURTESY OF SEVERAL FEATURES...THE FIRST AN UPPER
LEVEL DISTURBANCE PUSHING INTO CENTRAL INDIANA WITH A WELL DEFINED
CLOSED CIRCULATION ON WATER VAPOR SATELLITE IMAGERY. THE SECOND IS A
COLD FRONT STRETCHED SOUTHWEST FROM NORTHERN LAKE MICHIGAN...THROUGH
CENTRAL WISCONSIN...THEN ORIENTED WEST-EAST IN MOST OF IOWA. SPC
MESOANALYSIS SHOWS MODERATE INSTABILITY WITH GOOD LOW LEVEL LAPSE
RATES...BUT POOR SHEAR...AND MODEST PW VALUES. THEREFORE LOCALLY
HEAVY RAINFALL AND GUSTY WINDS WILL REMAIN THE PREDOMINANT HAZARDS
THROUGH THE AFTERNOON AND EARLY EVENING HOURS. THESE STORMS ARE
PRODUCING OUTFLOW BOUNDARIES THAT WILL LOCALLY INCREASE
CONVERGENCE SUGGESTING SCATTERED STORMS REMAIN POSSIBLE AREA-WIDE.
WHILE THE CONVECTIVE EVOLUTION IS STILL A BIT UNCERTAIN...EXPECT A
DIURNAL DECREASE IN THE COVERAGE AWAY FROM THE COLD FRONT AS THE
UPPER LEVEL LOW ENTERS INDIANA EXITS TO THE EAST...ESPECIALLY INTO
EASTERN ILLINOIS AND NORTHWEST INDIANA. ADDITIONALLY...MODEL
GUIDANCE STALLS THE FRONT OUT ALONG A DUBUQUE TO ROCKFORD TO
MILWAUKEE LINE. THE NEXT SET OF DISTURBANCES PROPAGATE PARALLEL TO
THE COLD FRONTAL BOUNDARY...THUS HAVE RETAINED HIGHEST POPS IN NORTH
CENTRAL ILLINOIS AND ALONG THE WISCONSIN BORDER. A TRAILING
DISTURBANCE IN WESTERN IOWA WILL MOVE THROUGH THE AREA OVERNIGHT
WHICH MAY ALLOW SOME FURTHER EASTWARD PROGRESSION OVERNIGHT.
HEIGHT RISES AND SUBSIDENCE IN WAKE OF THE DEPARTING DISTURBANCE BUT
BROAD SW MOIST LOWER LEVEL FLOW SUPPORTS LOWER POPS BUT A QUIETER
PERIOD IN GENERAL. A STRONG UPPER LEVEL LOW WILL BE WORKING EASTWARD
THROUGH THE CENTRAL PLAINS ON TUESDAY. WHILE THE STRONGEST STORMS
APPEAR TO BE IN IOWA...SOME MAY SNEAK INTO OUR AREA AS WELL LATER IN
THE DAY...BUT MORE LIKELY IN THE EVENING. WEAK INSTABILITY WILL BE
PRESENT DURING THE DAY COUPLED WITH INCREASING SHEAR AND MAY SUPPORT
SCATTERED DEVELOPMENT AGAIN DURING THE AFTERNOON.
KMD
&&
.LONG TERM...
310 PM CDT
TUESDAY NIGHT THROUGH THURSDAY...
THE PERIOD WILL BEGIN FAIRLY ACTIVE AS A NOW CLOSED UPPER LEVEL
SYSTEM CONTINUES TO SLOWLY PROGRESS EAST THROUGH THE NORTHERN
PLAINS AND UPPER MIDWEST. GUIDANCE IN FAIR AGREEMENT WITH OVERALL
EVOLUTION/PLACEMENT OF THIS SYSTEM AS WELL SEVERAL IMPULSES
LIFTING NORTHEAST ACROSS THE CWA/REGION...WHILE SURFACE LOW AND
BOUNDARY REMAIN WELL TO THE NORTHWEST AND WEST DURING THIS TIME.
ALTHOUGH PLACEMENT OF STRONGER AND MORE WIDESPREAD THUNDERSTORM
DEVELOPMENT WILL INITIALLY BE SITUATED WEST OF THE
CWA...INCREASING MOISTURE AND INSTABILITY OUT AHEAD OF THIS SYSTEM
TUESDAY/TUESDAY NIGHT WHILE PERSISTENT FORCING IS PRESENT COULD
ALLOW FOR SCATTERED DEVELOPMENT ACROSS THE CWA. FOCUS WILL THEN
SHIFT TOWARDS MORE WIDESPREAD DEVELOPMENT APPROACHING OUT AHEAD OF
EASTWARD MOVING FRONTAL BOUNDARY OVER IOWA. THESE
THUNDERSTORMS...DEVELOPING THROUGHOUT THE DAY TUESDAY...WILL BE
APPROACHING THE CWA BY THE MID TO LATE EVENING TIME FRAME. WITH
PERSISTENT FORCING THROUGHOUT THE NIGHT...WOULD EXPECT SHOWERS AND
THUNDERSTORMS TO BE POSSIBLE OVER MUCH OF THE CWA. ALTHOUGH
CONFIDENCE IS HIGHER WITH COVERAGE...CONFIDENCE IS LOWER WITH
REGARD TO INTENSITY OF THESE STORMS. QUESTIONS AS TO HOW MUCH THE
ATMOSPHERE WILL DESTABILIZE ON TUESDAY WILL PLAY A FACTOR WITH
INTENSITY MAINTAINING ITSELF WEDNESDAY EVENING. DO THINK AT LEAST
A FEW/ISOLATED STRONGER STORMS WILL BE POSSIBLE...BUT WILL NEED TO
MONITOR FOR POSSIBLE HIGHER COVERAGE OF THESE STRONGER STORMS.
WHILE FRONTAL BOUNDARY WILL CONTINUE TO PUSH EAST WEDNESDAY
MORNING...THUNDERSTORM CHANCES WILL BE ENDING FROM WEST TO EAST
WITH THE ARRIVAL OF MUCH DRIER AIR ON BACKSIDE OF THIS SYSTEM.
HOWEVER...THERE IS SOME VARIABILITY WITH HOW QUICKLY THIS FRONT
PUSHES THROUGH. WITH THIS SYSTEM CLOSING ITSELF OFF...I AM A
LITTLE CONCERNED THAT A MORE PREFERRED SOLUTION WOULD BE FOR A
SLOWER TIME FRAME. IF THIS WERE TO OCCUR...THEN THERE WOULD BE AN
ADDITIONAL CHANCE FOR STRONG TO SEVERE THUNDERSTORMS ACROSS THE
EASTERN CWA WEDNESDAY AS MOISTURE/INSTABILITY WOULD CONTINUE TO
STREAM NORTHWARD OUT AHEAD OF IT. HOWEVER...WOULD THINK ALREADY
PRESENT CLOUD COVER AND PRECIP WOULD LIMIT HOW UNSTABLE THE CWA
WOULD BE...WITH BETTER INSTABILITY LIKELY STAYING EAST OF THE CWA.
THUNDERSTORM CHANCES WILL LIKELY DIMINISH FROM WEST TO EAST IN THE
AFTERNOON AND ALTHOUGH PRECIP CHANCES MAY LINGER IN THE
EVENING...THUNDER SHOULD STAY TO THE EAST. HIGH TEMPERATURES ON
WEDNESDAY WILL LIKELY OCCUR EARLY IN THE DAY WEDNESDAY AND WHILE
STRONGER WESTERLY WINDS INCREASE INTO THE AFTERNOON. DESPITE SOME
TIMING DIFFERENCE WITH THE EVOLUTION OF THIS LARGE SYSTEM...WITH
DRIER AIR WORKING IN AND BETTER FORCING EXITING...THURSDAY IS
APPEARING TO BE DRY.
RODRIGUEZ
THURSDAY NIGHT THROUGH MONDAY
THE MAIN POINT OF INTEREST FOR THE REST OF THIS WEEK AND INTO THE
WEEKEND IS AN UPPER LEVEL DISTURBANCE AND ASSOCIATED SFC LOW.
WATER VAPOR SATELLITE SHOWS A MID-LEVEL TROUGH DEVELOPING OVER THE
DAKOTAS THAT WILL PROGRESS EAST THROUGH THE UPPER GREAT LAKES
REGION THE NEXT COUPLE OF DAYS. BOTH NAM AND GFS GUIDANCE ARE IN
RATHER GOOD AGREEMENT WITH THE TIMING AND INTENSITY OF THIS
DISTURBANCE. THIS TAKES THE CENTER OF THE LOW NORTH OF THE CWA
THROUGH MN AND WI. POPS ARE PROBABLE WITH THIS SETUP WITH EMBEDDED
WAVES WITHIN THE TROUGH, HOWEVER THERE IS UNCERTAINTY AS TO THE
AMOUNT OF POPS THE AREA WILL SEE WITH THIS DISTURBANCE. SATURDAY
LOOKS TO BE THE FAVORABLE DAY FOR CONVECTION WITH AN ISOLATED
THUNDERSTORM. COVERAGE OF TSRA WILL LIKELY BE SMALL. EXPECT TEMPS
TO DROP WITH FROPA BUT RECOVER BACK INTO THE 80S WITH SWLY FLOW AT
THE SFC. DEWPOINTS LOOK TO STAY PUT IN THE LOWER TO MID 60S. THE
SFC LOW WILL LEAD TO DEVELOPMENT OF STRONG PRESSURE GRADIENT
FAVORING STRONG WIND GUSTS AS THIS DISTURBANCE PROGRESSES ACROSS
THE REGION.
KRULL
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* PERIODIC CHANCES FOR THUNDERSTORMS.
* CHANCE FOR FOG OR LOW CIGS TUESDAY MORNING.
BMD
//DISCUSSION...UPDATED 06Z...
SCATTERED SHOWERS AND THUNDERSTORMS ARE IN PLACE ACROSS NORTHERN
ILLINOIS LATE THIS EVENING AND WILL CONTINUE THOUGH SOME OF THE
OVERNIGHT HOURS...THOUGH DO EXPECT A GENERAL DIMINISHING TREND IN
THE INTENSITY AND COVERAGE AS FORCING BEGINS TO EXIT EAST AND
INSTABILITY CONTINUES TO WANE NOCTURNALLY. WILL HAVE TO MONITOR
THE THREAT FOR LOW CIGS OR FOG DEVELOPING OVERNIGHT...ESPECIALLY
IF THERE IS PARTIAL CLEARING WHICH WILL ALLOW RADIATIVE COOLING
GIVEN LIGHT WINDS.
DURING THE DAY TUESDAY...INSTABILITY QUICKLY BUILDS THROUGH THE
MORNING WITH FORECAST SOUNDINGS SHOWING UNCAPPED PARCELS BY LATE
MORNING AND EARLY AFTERNOON. WOULDNT BE SURPRISED TO SEE A FEW
POP UPS HOWEVER TRANSIENT UPPER LEVEL RIDGING SHOULD SUPPRESS ANY
MORE WIDESPREAD CONVECTION EARLY IN THE DAY. BY MID AFTERNOON
HOWEVER... MID LEVEL HEIGHT FALLS BEGIN TO OVERSPREAD THE REGION
AHEAD OF A POTENT SYSTEM LIFTING ACROSS THE PLAINS. THE FOCUS
TOMORROW AFTERNOON AND EVENING SHOULD BE ALONG AND WEST OF THE
MISSISSIPPI RIVER HOWEVER GIVEN THE INSTABILITY AND BROAD SCALE
ASCENT CANNOT RULE OUT ISOLATED ACTIVITY NEAR THE
TERMINALS...ESPECIALLY RFD. EXPECT THUNDERSTORMS TO MOVE INTO
NORTHERN ILLINOIS LATE EVENING INTO THE EARLY OVERNIGHT HOURS.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE IN WIND TRENDS.
* LOW-MEDIUM CONFIDENCE IN TSRA/SHRA TIMING.
* LOW CONFIDENCE IN CIG/VSBY TRENDS EARLY TUESDAY MORNING.
BMD
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
* WEDNESDAY...CHANCE OF TSRA. STRONG/GUSTY SOUTHWEST WINDS.
* THURSDAY...DRY/VFR. STRONG/GUSTY WESTERLY WINDS.
* FRIDAY...DRY/VFR. SOUTH/SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. SOUTH/SOUTHEAST WINDS.
* SUNDAY...CHANCE OF TSRA. SOUTHWEST WINDS.
&&
.MARINE...
344 PM CDT
VARYING WINDS ACROSS THE LAKE THIS AFTERNOON ARE DUE TO LINGERING
BOUNDARY SITUATED OVER THE LAKE WHILE SURFACE LOW/TROUGH REMAINS
TO THE WEST. THESE VARYING WINDS WILL LIKELY PERSIST ON TUESDAY
AND INTO A PORTION OF TUESDAY NIGHT...BEFORE WINDS ACROSS THE
ENTIRE LAKE TURN MORE SOUTHERLY TUESDAY NIGHT INTO WEDNESDAY. THIS
WILL BE IN RESPONSE TO APPROACHING AND STRENGTHENING SURFACE LOW
OVER THE UPPER MIDWEST. EXPECT SPEEDS TO BE INCREASING TUESDAY
NIGHT BUT EXPECT SPEEDS TO REALLY RAMP UP ON WEDNESDAY AND
ESPECIALLY WEDNESDAY NIGHT AS THIS LOW FURTHER
STRENGTHENS/APPROACHES. HAVE MAINTAINED TO 30 KT WINDS ACROSS THE
LAKE...BUT AM A LITTLE CONCERNED THAT A PERIOD OF AT LEAST GALE
FORCE GUSTS WILL BE POSSIBLE...ESPECIALLY WEDNESDAY NIGHT. THESE
STRONGER WINDS WILL LIKELY BE PRESENT ACROSS THE NEARSHORE
WEDNESDAY INTO WEDNESDAY EVENING...BUT THESE HIGHER GUSTS MAY BE
POSSIBLE WELL INTO WEDNESDAY NIGHT. ALTHOUGH THESE STRONGER WINDS
MAY STILL BE OCCURRING THURSDAY MORNING...EXPECT SPEEDS TO BE
LOWERING INTO THE AFTERNOON.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS DES MOINES IA
417 AM CDT TUE AUG 18 2015
.SHORT TERM /TODAY/...
ISSUED AT 411 AM CDT TUE AUG 18 2015
SHOULD BE A FAIRLY ACTIVE DAY TODAY AS AN UPPER TROUGH OVER THE
NORTHERN PLAINS DEEPENS AND DEVELOPS A CLOSED LOW AS IT MOVES INTO
MN WEDNESDAY MORNING. THERE APPEARS TO BE SEVERAL VORT MAXES OVER
THE PLAINS ASSOCIATED WITH THIS TROUGH WHICH WILL LIKELY SWEEP INTO
NORTHWEST AND NORTH CENTRAL IOWA TODAY. AT THE SURFACE...LOW
PRESSURE OVER NORTH CENTRAL KANSAS IS FORECAST TO LIFT NORTHEAST
INTO WESTERN THEN NORTHWEST IOWA BY LATE AFTERNOON BEFORE MOVING
INTO SOUTH CENTRAL MINNESOTA TONIGHT. A WARM FRONT WILL SHIFT
ACROSS CENTRAL IOWA LATER THIS MORNING INTO THE AFTERNOON BRINGING
THE FIRST ROUND OF PRECIPITATION TO CENTRAL IOWA. SHEAR THIS
MORNING IS NOT OVERLY IMPRESSIVE BUT WILL INCREASE AND DEEPEN WITH
TIME. CAPE VALUES INCREASE THIS MORNING THEN MODELS DIMINISH CAPE
THIS AFTERNOON BEFORE BRIEFLY INCREASING IT AGAIN LATE AFTERNOON
INTO THE EVENING ACROSS THE SOUTHWEST WITH THE PASSAGE OF A COLD
FRONT AS THE SURFACE LOW SHIFTS INTO MN. QC FORCING IS PARTICULARLY
IMPRESSIVE THIS MORNING ESPECIALLY OVER THE NORTH.
PWATS ACROSS THE NORTHWEST INTO NORTH CENTRAL APPROACH 2 INCHES AND
THIS IS OVER LOCATIONS THAT GOT QUITE A BIT OF RAINFALL IN THE
RECENT PAST. THE POTENTIAL FOR HEAVY RAINFALL COMBINED WITH ONE
HOUR FLASH FLOOD GUIDANCE OF 1.6 INCHES OR SO HAS PROMPTED THE
ISSUANCE OF A FLASH FLOOD WATCH ACROSS MUCH OF NORTHWEST INTO NORTH
CENTRAL IOWA FOR TODAY THOUGH I DO EXPECT THE HEAVIEST RAINFALL
FROM MID TO LATE MORNING INTO THE EARLY AFTERNOON.
FURTHER SOUTH WHERE THE BETTER INSTABILITY WILL RESIDE WILL BE A
CONDITIONAL POTENTIAL FOR SEVERE WEATHER FROM MID AFTERNOON INTO
EARLY EVENING WITH THE FRONTAL PASSAGE. THERE IS A FAIR AMOUNT OF
UNCERTAINTY AS TO WHAT THE EXTENT OF THE MORNING CONVECTION WILL BE
AND HOW MUCH WE WILL DESTABILIZE LATER TODAY AS MANY OF THE HI-RES
MODELS DRIBBLE CONVECTION ACROSS US FOR MUCH OF THE DAY BUT THEY DO
IN FACT ALL SUGGEST A SECOND ROUND OF CONVECTION IN THE MID
AFTERNOON THROUGH EARLY TO MID EVENING. AT PRESENT THE HRRR SEEMS
TO HAVE A DECENT HANDLE ON THE PRECIP THOUGH ITS A LITTLE TOO HEAVY
ON THE NORTHWARD EXTENT. THE WRF IS CAPTURING THE SOUTHERN PRECIP
AREA A LITTLE BETTER SO I TRIED TO GO WITH A BLEND OF THOSE TWO
MODELS. THE 00Z NAMDNG ALSO HAD A DECENT HANDLE ON PRECIP BUT THE
06Z RUN IS MISSING THE EXPANDING PRECIP ACROSS THE SOUTHWEST. I
HELD TEMPS DOWN A DEGREE OR TWO WITH ESPECIALLY SOUTH WITH THE
EXPECTED CLOUD COVER AND PRECIP. AS FOR POPS...I WENT FAIRLY HIGH
POPS FOR TODAY. IT SHOULD NOT BE RAINING ALL DAY BUT THERE WILL BE
A FEW ROUNDS OF PRECIP AND THE SCATTERED NATURE OF THE STORMS WILL
MAKE IT VERY DIFFICULT TO PIN DOWN TIME AND LOCATION.
.LONG TERM /TONIGHT THROUGH MONDAY/...
ISSUED AT 411 AM CDT TUE AUG 18 2015
FORECAST CHALLENGE EARLY ON IS WHERE OUR LOW WILL BE AT THE START OF
THE LONG TERM FCST PERIOD. MODELS SOMEWHAT SCATTERED WITH PLACEMENT
OF THE LOW AT 00Z WED. THE 00Z TUE EURO/GEM/UKMET ESSENTIALLY THE
MIDDLE PATH. THE 00Z TUE GFS IS NOW A FAST OUTLIER...AND THE 00Z
TUE NAM IS A SLIGHTLY SLOW OUTLIER THAN THE MIDDLE PATH MODELS.
AVAILABLE BAROCLINICITY AND RUN-TO-RUN INCREASINGLY ANOMALOUS
UPSTREAM 500MB SHORTWAVE AND -4 STD DEV SFC LOW SUGGEST THE
SLOWER...MORE ROBUST PATH MAY BE MORE REASONABLE TO FOLLOW. THUS
HAVE GONE WITH A BLEND OF THE NAM/EURO/GEM/UKMET. THIS BLEND
PLACES THE LOW IN NW IOWA AT 00Z WED. AT 00Z WED...THE BEST SLUG
OF FORCING WILL LIKELY BE EXITING OUR CWA AND THERE WILL BE THE
ATTENDANT COLD FRONT DROPPING DOWN ALONG OUR WESTERN COUNTIES INTO
MISSOURI.
SVR THREAT...0-6 KM MUCAPE VALUES MARGINAL AT 1000-1200 J/KG. 0-1 KM
HELICITY DECENT AS IT APPROACHES 200 M2/S2. LCL HEIGHTS ARE
SUFFICIENTLY LOW. GIVEN CLIMATOLOGY...STORM MODE MAY EVOLVE TO
LINEAR/BOWING OVERNIGHT. DCAPE VALUES EXCEED 1000 J/KG. NAM PICKING
UP ON PWATS UPWARDS OF 2 INCHES WITH THIS BOUNDARY PASSAGE...SO A
BRIEF HEAVY DOWNPOUR POSSIBLE. ADDITIONALLY...NAM PLACES RIGHT
ENTRANCE REGION OF 100KT JET STREAK IN TARGETED AREA.
HOWEVER...CONFIDENCE NOT THE GREATEST DUE TO LACK OF MODEL
CONSISTENCY AND THE FACT RAIN/CLOUDS THROUGHOUT THE DAY WILL
HINDER DESTABILIZATION. IF STORMS DO GO WITH THE COLD
FRONT...TORNADOES/DAMAGING WINDS LIKELY THE PRIMARY THREATS.
BY 09-12Z WED...BOUNDARY SHOULD BE WELL EAST OF DMX CWA. STRONG
W/NW CAA WILL BE IMMEDIATELY USHERED INTO IOWA AS 850MB TEMPS
SHOULD BE NEAR 8C ON OUR WESTERN CWA EDGE AND 11C ON OUR EASTERN
EDGE. WEDNESDAY AFTERNOON...LOW PROGGD TO DEEPEN TO MID 990MB
RANGE OVER NW WI...WHICH IS VERY ATYPICAL FOR THIS TIME OF YEAR.
GEFS ENSEMBLES SHOW THIS IS NEARING -4 TO -5 STD DEV. PRESSURE
GRADIENT NOT AS TIGHT IN IA AS IT WILL BE IN MN/WESTERN WI.
NONETHELESS...AROUND 3MB/100 KM...DEPENDING ON MODEL PREFERENCE.
FCST SOUNDINGS STILL SHOW AROUND 40 KTS TO THE TOP OF THE MIXED
LAYER. SO AM EXPECTING SFC WINDS IN THE 15 TO 25 MPH RANGE WITH
GUSTS NEARING 35 MPH...ESPECIALLY IN OUR NORTH. PAST SEVERAL MODEL
RUNS HAVE BEEN SUGGESTING ST/SC DECK WITH THE DEFORMATION ZONE
LINGERING ACROSS NORTHERN IA. THUS HAVE KEPT SLIGHT POPS WITH
MINIMAL QPF GOING THROUGH WED EVE. AT THE VERY LEAST...MAX TEMPS
WILL BE HELD DOWN DUE TO THE CLOUD COVER. WENT LOW 60S NORTH...BUT
THIS MAY NEED TO BE KNOCKED DOWN A FEW DEGREES IF ST DECK HOLDS.
THURSDAY INTO SATURDAY...SFC HIGH PRESSURE WILL PASS FROM THE OZARKS
INTO THE OHIO VALLEY REGION. THIS HIGH WILL BE STRONG ENOUGH TO KEEP
DMX CWA DRY THU AND FRI. TEMPS HAVE CERTAINLY TRENDING UPWARDS FOR
FRIDAY AND SATURDAY. THUS HAVE GONE A FEW DEGREES ABOVE GUIDANCE TO
ADD VALUE TO TEMPERATURE FCST.
SINCE LAST FRI...MODELS HAVE BEEN PLACING IA IN RETURN FLOW BY THE
WEEKEND. 00Z TUE LONG RANGE MODELS CONTINUE THIS...KEEPING THE GULF
WIDE OPEN WITH A 35 KT LLJ PRIMED TO TRANSPORT GULF MOISTURE INTO
IOWA. THIS SETUP WILL INCREASE TEMPS BACK INTO THE 80S AND BRING A
RETURN OF POPS FOR THE WEEKEND.
SUNDAY INTO EARLY NEXT WEEK...MODELS IN SURPRISINGLY GREAT
AGREEMENT...PLUS SHOWING RUN-TO-RUN CONSISTENCY GOOD WITH BRINGING A
STRONG SFC HIGH TOWARDS IOWA. AS CONFIDENCE/CONSISTENCY
INCREASING...TEMPS HAVE BEEN TRENDING DOWNWARD WITH CAA EXPECTED
AHEAD OF THIS HIGH. MAY NEED TO LOWER TEMPERATURES EVEN FURTHER IF
THIS SETUP HOLDS.
&&
.AVIATION...18/06Z
ISSUED AT 1147 PM CDT MON AUG 17 2015
SHOWERS AND THUNDERSTORMS WILL CONTINUE TO DEVELOP OVER WEST-
CENTRAL IOWA DURING THE OVERNIGHT HOURS AND SPREAD EAST-NORTHEAST
LIKELY AFFECTING FOD/MCW/DSM PRIOR TO NEXT TAF UPDATE. CIGS WILL
CONTINUE TO BOUNCE FROM IFR TO MVFR TO VFR DEPENDING ON IF SITE
RECEIVES RAIN...BUT HIGHER CONFIDENCE IN EXTENDED TIME FRAME OF
MVFR CIGS/VIS AND KEPT MENTION AS RAIN LOOKS TO SPREAD OVER MUCH
OF CENTRAL IOWA TOWARDS 12Z-14Z TUESDAY. THE MORE WIDESPREAD AND
HEAVIER RAIN BY MIDDAY INTO THE AFTERNOON WILL BRING THE BEST
POTENTIAL FOR IFR VIS AND CIGS. WINDS INCREASE AND SHIFT WEST-
NORTHWEST TUESDAY EVENING BEHIND THE COLD FRONT.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH THIS EVENING FOR CALHOUN-CARROLL-
CRAWFORD-EMMET-HANCOCK-HUMBOLDT-KOSSUTH-PALO ALTO-POCAHONTAS-SAC-
WEBSTER-WINNEBAGO-WRIGHT.
&&
$$
SHORT TERM...FAB
LONG TERM...KOTENBERG
AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1116 PM MDT MON AUG 17 2015
.UPDATE...
ISSUED AT 504 PM MDT MON AUG 17 2015
ADVANCING COLD FRONT/COLD POOL FROM THE NORTHEAST HAS CLEARED ST
FRANCIS AND COLBY AND RAPIDLY HEADING TOWARDS THE GLD AREA. IN
ADDITION TO THE WIND SHIFT AND EVEN MORE INCREASED LOW LEVEL
SHEAR...MESOANALYSIS INDICATES STRONG CINH IN COOLER AIR TO THE
NORTH. THINK THIS WILL FOR AT LEAST A WHILE ACT AS A NORTHERN
LIMIT TO SFC BASED CONVECTION AND HAVE HIGHLIGHTED AND INCREASED
POPS IN AREAS TO THE SOUTH OF AFOREMENTIONED FEATURE. ALTHOUGH
STORMS ARE MOVING...RAINFALL RATES AROUND AN INCH AND A HALF PER
HOUR HAVE BEEN OBSERVED KEEPING HEAVY RAIN SIG THREAT. QUICK
MOTION SHOULD LIMIT FLOOD POTENTIAL AND AT THIS TIME HAVE OPTED
AWAY FROM ANY LARGE SCALE WATCH.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 250 PM MDT MON AUG 17 2015
EARLY AFTERNOON WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW
STRENGTHENING TROUGH ACROSS MONTANA WITH SHARP PV HEIGHT ANOMALY
DIGGING INTO NORTHWESTERN WYOMING. DIFFLUENT FLOW IS IN PLACE
ACROSS NORTHERN COLORADO WITH INCREASING DIVERGENT SIGNATURE
AHEAD OF APPROACHING UPPER LEVEL JET. AT THE SURFACE A STATIONARY
FRONT EXTENDS FROM NORTH CENTRAL KANSAS TO SOUTHEAST
COLORADO...ACROSS THE SOUTHEAST PART OF OUR CWA...WITH A WEAK
SURFACE TROUGH AXIS EXPENDING ACROSS THE NW PART OF OUR FORECAST
AREA.
THUNDERSTORMS SHOULD INITIATE ACROSS EASTERN COLORADO THIS
AFTERNOON WITH ACTIVITY INCREASING IN COVERAGE AND SPREADING EAST
INTO OUR CWA THROUGH THE EVENING/OVERNIGHT. BEST FORCING IS
ADVERTISED 03-06Z OVER OUR CWA AND QUICKLY TRANSITIONS EASTWARD
THROUGH TUESDAY MORNING. AS THE UPPER LOW DEEPENS AND EVENTUALLY
CLOSES OFF OVER NEBRASKA DRY SLOT/SUBSIDENT REGION WILL MOVE OVER
OUR CWA WHICH SHOULD RAPIDLY DECREASE ANY SHOWER/THUNDERSTORM
CHANCES. STRONG COLD FRONT WILL DROP DOWN ACROSS THE REGION
TUESDAY MORNING AND COMBINED WITH INCREASING SUBSIDENCE BRING
MILD/WINDY (VERY FALL-LIKE) CONDITIONS TO OUR CWA. THERE MAY ALSO
BE A REDEVELOPMENT OF DENSE FOG/LOW STRATUS OVER SW NEBRASKA
DEPENDING ON THUNDERSTORM ACTIVITY/MIXING AND FRONTAL TIMING.
REGARDING SEVERE POTENTIAL TONIGHT...RAP ANALYSIS SHOWS SB CAPE
AXIS 2500-3500 J/KG AND DEEP BULK EFFECTIVE SHEER VALUES 40-50KT
ACROSS EASTERN COLORADO. CONSIDERING THE DEEP LAYER SHEER AND
INSTABILITY WE ARE ANTICIPATING ORGANIZED SUPERCELLS DEVELOPING
LATE THIS AFTERNOON AND SLOWLY PROGRESSING EASTWARD (MEAN STORM
MOTIONS 10-20KT). THERE IS A WINDOW WITH LOW LEVEL TURNING ALONG
SURFACE TROUGH AXIS FOR TORNADOES WITH MORE ORGANIZED CELLS...WITH
PRIMARY THREAT VERY LARGE HAIL (2"+) AND DAMAGING WINDS. AS THIS
ACTIVITY ORGANIZES INTO A MCS/THUNDERSTORM CLUSTER TORNADO THREAT
SHOULD DIMINISH. TORNADO WATCH 490 IS CURRENTLY IN EFFECT FOR OUR
EASTERN COLORADO COUNTIES...AND PATTERN IS BEING MONITORED FOR
ANY OTHER POSSIBLE SEVERE WATCHES AS THIS UNFOLDS THIS
AFTERNOON/EVENING.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 156 PM MDT MON AUG 17 2015
JET MAX ROTATING AROUND BACK OF THE UPPER TROUGH WILL BRING
SCATTERED SHOWERS TO THE AREA TUESDAY NIGHT THROUGH WEDNESDAY
MORNING UNDER THE DIVERGENT LEFT EXIT REGION. MODEL QPF IS
LIGHT...GENERALLY BETWEEN A TENTH AND A QUARTER OF AN INCH...BUT
RATHER WIDESPREAD SO POPS MAY NEED TO BE INCREASED IF THOSE TRENDS
CONTINUE. POINT FORECAST SOUNDINGS ACTUALLY SHOW ICE IN THE COLUMN
BUT THE SURFACE BASED WARM LAYER EXTENDS TO AROUND 6KFT AGL WHICH
WILL BE MORE THAN SUFFICIENT TO KEEP ANY KIND OF SNOW FROM
REACHING THE GROUND. LOW TEMPERATURES A BIT TRICKY...WITH CLOUDS
POTENTIALLY KEEPING THEM FROM REACHING THE UPPER 40S BUT IF THE
RAIN IS PROLONGED MIGHT WET BULB DOWN TO NEAR THAT ANYWAY. EITHER
WAY IT WILL BE A RATHER CHILLY MORNING FOR MID AUGUST.
UPPER TROUGH WILL MOVE OUT WEDNESDAY AFTERNOON WITH NORTHWEST
FLOW ALOFT THROUGH THE END OF THE WEEK. PRECIPITATION CHANCES
DURING THAT TIME WILL BE SLIM TO NONE WITH NO UPPER SHORTWAVES IN
THE MODELS AND LIMITED MOISTURE AVAILABLE. TEMPERATURES WILL
REBOUND QUICKLY AFTER THE MIDWEEK COOL DOWN WITH ABOVE NORMAL
HIGHS BY FRIDAY. THE UPPER FLOW WILL TRANSITION TO ZONAL AND THEN
SOUTHWEST OVER THE WEEKEND AS ANOTHER TROUGH DIGS INTO THE
NORTHERN ROCKIES. THE NEXT BEST CHANCE FOR THUNDERSTORMS WILL BE
SATURDAY AFTERNOON/EVENING AS DYNAMICS AND SURFACE COLD FRONT
ASSOCIATED WITH THAT SYSTEM MOVE THROUGH THE CENTRAL PLAINS. A
LITTLE EARLY...BUT RIGHT NOW BEST COMBINATION OF INSTABILITY AND
SHEAR WILL BE CONFINED TO EASTERN PARTS OF THE FORECAST
AREA...NORTON TO GOVE...WHICH WOULD BE THE FAVORED AREAS FOR ANY
SEVERE THREAT. IF THAT TIMING VERIFIES SUNDAY AND MONDAY WILL BE
DRY AND A LITTLE COOLER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1111 PM MDT MON AUG 17 2015
DIFFICULT...POTENTIAL LONG DURATION IFR TO LIFR CONDITIONS
EXPECTED OVERNIGHT PRIOR TO ARRIVAL OF STRONG COLD FRONT SHORTLY
AFTER SUNRISE. ONCE THE FRONT PASSES...WINDS WILL SHIFT TO THE
NORTH WITH VISBY AND CIGS RISING QUICKLY BEHIND GUSTY NORTHERLY
WINDS. BEFORE THE FROPA...MCK WILL LIKELY REMAIN AT OR NEAR LIFR
CONDITIONS THROUGH THE NIGHT AS LARGE AREA OF STRATUS DEVELOPED
OVER THE AREA. MAY SEE SOME IMPROVEMENT BTWN 08-12Z WITH SHOWERS
MOVING THROUGH...BUT SHOULD NOT BE LONG LIVED. GLD IN A MUCH MORE
DIFFICULT POSITION AS COLD FRONT AS DRIFTED BACK AND FORTH ACROSS
THE AREA ALTHOUGH IT IS NOW ADVANCING SOUTH AGAIN. NOT ONLY DOES
THIS MAKE WIND FORECAST HIGHLY UNCERTAIN...BUT MOIST FOG
PRECONDITIONED AIR EXISTS TO THE NORTH OF THE FRONT...WITH MUCH
DRIER AIR TO THE SOUTH. HAVE ALREADY SEEN CONDITIONS VARY BTWN
LIFR AND VFR IN THE PAST FEW HOURS...BUT TEND TO THINK CURRENT VFR
CONDITIONS WILL FALL FOR A FEW HOURS BEFORE SFC WINDS BECOME
WESTERLY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JRM
SHORT TERM...DR
LONG TERM...024
AVIATION...JRM
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
514 AM EDT TUE AUG 18 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM EDT TUE AUG 18 2015
WV IMAGERY AND RAP ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
FROM NRN HUDSON BAY INTO THE NRN PLAINS RESULTING IN WNW FLOW
THROUGH THE NRN GREAT LAKES. A WEAK SHORTWAVE TROUGH AND AREA OF 850-
700 MB FGEN SUPPORTED A BAND OF SHOWERS OVER WRN UPPER MI. UPSTREAM
A VIGOROUS SHRTWV WAS MOVING THROUGH SD/NE. AT THE SFC...A WEAK
FRONTAL BOUNDARY EXTENDED FROM CNTRL LOWER MI THROUGH SE WI AND SW
IA TO LOW PRES OVER NRN KS. WITH HIGH PRES OVER NRN ONTARIO...LIGHT
NE WINDS PREVAILED ACROSS THE NRN LAKES.
EXPECT THE PCPN OVER THE WEST TO DIMINISH EARLY AS THE SHRTWV AND
FGEN LIFT MOVE OFF TO THE NORTHEAST. HOWEVER...SOME SCT -SHRA MAY
LINGER OVER THE SOUTH AS ANOTHER WEAK SHRTWV BRUSHES THE AREA TO THE
SE.
ATTENTION...WILL THEN TURN TO THE DEVELOPING AND UNSEASONABLY STRONG
LOW PRES SYSTEM MOVING OUT OF THE PLAINS. THE SD/NE SHRTWV WILL
SUPPORT A DEEPENING LOW MOVING INTO THE NW CORNER OF IA BY 00Z/WED
AND ERN MN BY 12Z/WED. THE MODELS HAVE TRENDED TOWARD A SLIGHTLY
SLOWER PROGRESSION OF THE LOW AS THE STRONG JET MOVING OUT OF THE
PLAINS HELPS CUT OFF THE MID LEVEL LOW. AN AREA OF STRONG MOISTURE
TRANSPORT AND 305K-310K ISENTROPIC ASCENT WILL BRING AN AREA OF RAIN
THROUGH UPPER MI TONIGHT...MAINLY AFTER MIDNIGHT. HOWEVER...THIS
TRANSIENT BAND IS EXPECTED TO BRING QPF AMOUNTS ONLY IN THE 0.25-
0.50 INCH RANGE OVER THE CNTRL AND ERN CWA. HIGHER AMOUNTS TO AROUND
AN INCH WILL BE POSSIBLE OVER THE FAR WEST CLOSER TO THE STRONGEST
DEEP LAYER QVECTOR CONV AND LIFT WHICH WILL REMAIN TO THE WEST OVER
NRN MN AND WRN LAKE SUPERIOR. WITH MODEST MUCAPE VALUES INTO THE 200-
400 J/KG RANGE ONLY ISOLD TSRA ARE EXPECTED.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 339 AM EDT TUE AUG 18 2015
BY 12Z WED AN INTENSIFYING LOW WILL BE APPROACHING OR OVER THE WRN
CWA. THE 00Z/18 GFS HAS COME INTO GOOD AGREEMENT WITH THE 12Z/17
ECMWF IN DEEPENING THE SFC LOW TO 993-995MB AS THE SYSTEM CLOSES OFF
OVER WRN LAKE SUPERIOR WED. THE NAM . BY 12Z THU THE LOW WILL BE
OCCLUDED N OF LAKE SUPERIOR AND WILL QUICKLY SHUNT N TO HUDSON BAY
BY 00Z FRI.
OVERALL EXPECTATIONS HAVE NOT CHANGED MUCH FROM THE DAY SHIFT MON. A
SURGE OF PRECIP WILL BE EXITING N WED MORNING AHEAD OF THE COLD
FRONT AND THEN DRY SLOT THAT WILL MOVE IN FROM THE SW WED LATE
MORNING/AFTERNOON. COULD SEE SOME STRONG TO POSSIBLY SEVERE STORMS
ALONG THE COLD FRONT AS EFFECTIVE SHEAR IS ENHANCED...BUT OTHERWISE
NOT EXPECTING SEVERE STORMS. AFTER THE DRY SLOT MOVES INTO MAINLY
THE CENTRAL AND ERN CWA...WRAP AROUND PRECIP/MOISTURE WILL MOVE INTO
WRN UPPER MI. THE WRAP AROUND PRECIP WILL SPREAD TO NRN AND WRN
UPPER MI WED NIGHT AND CONTINUE THROUGH MOST OF THU. WED LOOKS WINDY
WITH S-SW WINDS GUSTING TO 25-35 MPH. WINDS THU WILL BE SIMILAR
STRENGTH OF WED...BUT OUT OF THE W.
FRI AND SAT LOOK DRY WITH SW FLOW ALONG AND A SFC HIGH OVER MUCH OF
THE ERN CONUS. HOWEVER...MODELS CONTINUE TO INDICATE THAT ANOTHER
STORM SYSTEM COULD BRING PRECIP SUN INTO MON...BUT DETAILS REMAIN
UNCLEAR AT THIS TIME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 125 AM EDT TUE AUG 18 2015
ALTHOUGH SOME -SHRA MAY IMPACT IWD AND PERHAPS CMX LATER...THERE
SHOULD BE ENUF LLVL DRY AIR TO MAINTAIN VFR CONDITIONS. AT SAW...AN
UPSLOPE NE FLOW CLOSER TO STALLED FNT JUST TO THE SE OF UPR MI IN
THE PRESENCE OF NOCTURNAL COOLING WL RESULT IN A DEVELOPMENT OF MVFR
CONDITIONS FOR A TIME THIS MRNG BEFORE DAYTIME HEATING BRINGS A
RETURN OF VFR WX FOR A SHORT TIME. LOWER MVFR CIGS WL RETURN TO THAT
SITE ALONG WITH THE CHC FOR SOME -SHRA LATE IN THE DAY AS THE
STALLED FNT BEGINS MOVING TO THE N. SOME -SHRA WL RETURN TO IWD AS
WELL...BUT DOWNSLOPE NATURE OF THE LLVL WIND THERE SHOULD MAINTAIN
VFR CONDITIONS AT THE ONSET OF ANY PCPN. A STRENGTHENING ESE FLOW
AHEAD OF DEEPENING LO PRES IN THE PLAINS WL BRING A RETURN OF MORE
WDSPRD -RA/MVFR CONDITIONS IN THE EVNG. IFR CONDITIONS WL BE LIKELY
AFTER THE END OF THIS CURRENT TAF PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 514 AM EDT TUE AUG 18 2015
HIGH PRES STRETCHING FROM SOUTHERN MANITOBA THROUGH JAMES BAY WILL
EXTEND A RIDGE INTO THE UPPER LAKES THROUGH THIS MORNING...RESULTING
IN LIGHT WINDS UNDER 15KT ACROSS LAKE SUPERIOR. THEN...AS LOW PRES
ORGANIZES AND STRENGTHENS OVER THE PLAINS TUE...NE WINDS WILL BEGIN
TO INCREASE...ESPECIALLY OVER WRN LAKE SUPERIOR WHERE GUSTS SHOULD
REACH 25-30KT LATE AFTN/EARLY EVENING. THIS LOW WILL BECOME
UNSEASONABLY DEEP FOR AUG AS IT LIFTS ACROSS FAR WRN LAKE SUPERIOR
WED AFTERNOON. 20-30KT WINDS ARE EXPECTED OVER MUCH OF THE LAKE
TONIGHT INTO WED. MAY SEE GALE FORCE GUSTS OVER FAR WRN LAKE SUPERIOR
IN THE NE WINDS AHEAD OF THE LOW TONIGHT AND THEN IN THE WESTERLY
WINDS ACROSS MAINLY CENTRAL LAKE SUPERIOR ON THU AS THE LOW LIFTS N
OF THE AREA. WINDS WILL DIMINISH TO UNDER 20KT FRI...AND THEN BEGIN
TO INCREASE AGAIN ON SAT AHEAD OF THE NEXT COLD FRONT MOVING OUT
ACROSS THE PLAINS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...KC
MARINE...JLB
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
503 AM EDT TUE AUG 18 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM EDT TUE AUG 18 2015
WV IMAGERY AND RAP ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
FROM NRN HUDSON BAY INTO THE NRN PLAINS RESULTING IN WNW FLOW
THROUGH THE NRN GREAT LAKES. A WEAK SHORTWAVE TROUGH AND AREA OF 850-
700 MB FGEN SUPPORTED A BAND OF SHOWERS OVER WRN UPPER MI. UPSTREAM
A VIGOROUS SHRTWV WAS MOVING THROUGH SD/NE. AT THE SFC...A WEAK
FRONTAL BOUNDARY EXTENDED FROM CNTRL LOWER MI THROUGH SE WI AND SW
IA TO LOW PRES OVER NRN KS. WITH HIGH PRES OVER NRN ONTARIO...LIGHT
NE WINDS PREVAILED ACROSS THE NRN LAKES.
EXPECT THE PCPN OVER THE WEST TO DIMINISH EARLY AS THE SHRTWV AND
FGEN LIFT MOVE OFF TO THE NORTHEAST. HOWEVER...SOME SCT -SHRA MAY
LINGER OVER THE SOUTH AS ANOTHER WEAK SHRTWV BRUSHES THE AREA TO THE
SE.
ATTENTION...WILL THEN TURN TO THE DEVELOPING AND UNSEASONABLY STRONG
LOW PRES SYSTEM MOVING OUT OF THE PLAINS. THE SD/NE SHRTWV WILL
SUPPORT A DEEPENING LOW MOVING INTO THE NW CORNER OF IA BY 00Z/WED
AND ERN MN BY 12Z/WED. THE MODELS HAVE TRENDED TOWARD A SLIGHTLY
SLOWER PROGRESSION OF THE LOW AS THE STRONG JET MOVING OUT OF THE
PLAINS HELPS CUT OFF THE MID LEVEL LOW. AN AREA OF STRONG MOISTURE
TRANSPORT AND 305K-310K ISENTROPIC ASCENT WILL BRING AN AREA OF RAIN
THROUGH UPPER MI TONIGHT...MAINLY AFTER MIDNIGHT. HOWEVER...THIS
TRANSIENT BAND IS EXPECTED TO BRING QPF AMOUNTS ONLY IN THE 0.25-
0.50 INCH RANGE OVER THE CNTRL AND ERN CWA. HIGHER AMOUNTS TO AROUND
AN INCH WILL BE POSSIBLE OVER THE FAR WEST CLOSER TO THE STRONGEST
DEEP LAYER QVECTOR CONV AND LIFT WHICH WILL REMAIN TO THE WEST OVER
NRN MN AND WRN LAKE SUPERIOR. WITH MODEST MUCAPE VALUES INTO THE 200-
400 J/KG RANGE ONLY ISOLD TSRA ARE EXPECTED.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 339 AM EDT TUE AUG 18 2015
BY 12Z WED AN INTENSIFYING LOW WILL BE APPROACHING OR OVER THE WRN
CWA. THE 00Z/18 GFS HAS COME INTO GOOD AGREEMENT WITH THE 12Z/17
ECMWF IN DEEPENING THE SFC LOW TO 993-995MB AS THE SYSTEM CLOSES OFF
OVER WRN LAKE SUPERIOR WED. THE NAM . BY 12Z THU THE LOW WILL BE
OCCLUDED N OF LAKE SUPERIOR AND WILL QUICKLY SHUNT N TO HUDSON BAY
BY 00Z FRI.
OVERALL EXPECTATIONS HAVE NOT CHANGED MUCH FROM THE DAY SHIFT MON. A
SURGE OF PRECIP WILL BE EXITING N WED MORNING AHEAD OF THE COLD
FRONT AND THEN DRY SLOT THAT WILL MOVE IN FROM THE SW WED LATE
MORNING/AFTERNOON. COULD SEE SOME STRONG TO POSSIBLY SEVERE STORMS
ALONG THE COLD FRONT AS EFFECTIVE SHEAR IS ENHANCED...BUT OTHERWISE
NOT EXPECTING SEVERE STORMS. AFTER THE DRY SLOT MOVES INTO MAINLY
THE CENTRAL AND ERN CWA...WRAP AROUND PRECIP/MOISTURE WILL MOVE INTO
WRN UPPER MI. THE WRAP AROUND PRECIP WILL SPREAD TO NRN AND WRN
UPPER MI WED NIGHT AND CONTINUE THROUGH MOST OF THU. WED LOOKS WINDY
WITH S-SW WINDS GUSTING TO 25-35 MPH. WINDS THU WILL BE SIMILAR
STRENGTH OF WED...BUT OUT OF THE W.
FRI AND SAT LOOK DRY WITH SW FLOW ALONG AND A SFC HIGH OVER MUCH OF
THE ERN CONUS. HOWEVER...MODELS CONTINUE TO INDICATE THAT ANOTHER
STORM SYSTEM COULD BRING PRECIP SUN INTO MON...BUT DETAILS REMAIN
UNCLEAR AT THIS TIME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 125 AM EDT TUE AUG 18 2015
ALTHOUGH SOME -SHRA MAY IMPACT IWD AND PERHAPS CMX LATER...THERE
SHOULD BE ENUF LLVL DRY AIR TO MAINTAIN VFR CONDITIONS. AT SAW...AN
UPSLOPE NE FLOW CLOSER TO STALLED FNT JUST TO THE SE OF UPR MI IN
THE PRESENCE OF NOCTURNAL COOLING WL RESULT IN A DEVELOPMENT OF MVFR
CONDITIONS FOR A TIME THIS MRNG BEFORE DAYTIME HEATING BRINGS A
RETURN OF VFR WX FOR A SHORT TIME. LOWER MVFR CIGS WL RETURN TO THAT
SITE ALONG WITH THE CHC FOR SOME -SHRA LATE IN THE DAY AS THE
STALLED FNT BEGINS MOVING TO THE N. SOME -SHRA WL RETURN TO IWD AS
WELL...BUT DOWNSLOPE NATURE OF THE LLVL WIND THERE SHOULD MAINTAIN
VFR CONDITIONS AT THE ONSET OF ANY PCPN. A STRENGTHENING ESE FLOW
AHEAD OF DEEPENING LO PRES IN THE PLAINS WL BRING A RETURN OF MORE
WDSPRD -RA/MVFR CONDITIONS IN THE EVNG. IFR CONDITIONS WL BE LIKELY
AFTER THE END OF THIS CURRENT TAF PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 443 PM EDT MON AUG 17 2015
HIGH PRES STRETCHING FROM SOUTHERN MANITOBA THROUGH JAMES BAY WILL
EXTEND A RIDGE INTO THE UPPER LAKES THRU TUE MORNING...RESULTING IN
LIGHT WINDS UNDER 15KT ACROSS LAKE SUPERIOR THRU TUE MORNING.
THEN...AS LOW PRES ORGANIZES AND STRENGTHENS OVER THE PLAINS
TUE...NE WINDS WILL BEGIN TO RAMP UP...ESPECIALLY OVER WRN LAKE
SUPERIOR WHERE GUSTS SHOULD REACH 25-30KT LATE AFTN/EARLY EVENING.
THIS LOW WILL BECOME UNSEASONABLY DEEP FOR AUG AS IT LIFTS ACROSS
FAR WRN LAKE SUPERIOR WED AFTN. 20-30KT WINDS ARE EXPECTED OVER MUCH
OF THE LAKE TUE NIGHT INTO WED. MAY SEE GALE FORCE GUSTS OVER FAR
WRN LAKE SUPERIOR IN THE NE WINDS AHEAD OF THE LOW TUE NIGHT AND
THEN IN THE WESTERLY WINDS ACROSS MAINLY CENTRAL LAKE SUPERIOR ON
THU AS THE LOW LIFTS N OF THE AREA. WINDS WILL DIMINISH TO UNDER
20KT FRI...AND THEN BEGIN TO INCREASE AGAIN ON SAT AHEAD OF THE NEXT
COLD FRONT MOVING OUT ACROSS THE PLAINS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...KC
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
340 AM EDT TUE AUG 18 2015
.UPDATE...
ISSUED AT 848 PM EDT MON AUG 17 2015
ADDED SOME ISOLD SHOWERS TO THE FCST FOR WRN UPR MI OVERNGT TO
ACCOUNT FOR AREA OF SHOWERS MOVING SLOWLY NE THRU NW WI AHEAD OF
DISTURBANCE IN SW MN AND UNDER COOLING CLD TOPS. POTENT SHRTWV
DIGGING INTO THE NRN PLAINS WL LIKELY CAUSE THE UPR FLOW TO BACK ENUF
TO LIFT THESE SHOWERS INTO THE WRN CWA. ONLY THE LATEST RAPID REFRESH
MODEL HAS A GOOD HANDLE ON THE LOCATION OF THE PCPN AT PRESENT TIME.
THIS MODEL SHOWS THESE SHOWERS SPREADING INTO WRN UPR MI AFTER MIDNGT
DESPITE SOME DRIER LLVL AIR THAT WL RESTRICT THE COVERAGE/INTENSITY.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 443 PM EDT MON AUG 17 2015
WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A BROAD TROF EXTENDING S
INTO THE NRN ROCKIES NRN PLAINS. POTENT LOOKING SHORTWAVE OVER SW MT
WILL GENERATE AN UNUSUALLY STRONG SFC LOW FOR AUG THAT WILL MOVE
ACROSS THE UPPER MISSISSIPPI VALLEY/UPPER GREAT LAKES TUE NIGHT/WED.
SYSTEM ON WATER VAPOR IMAGERY LOOKS STRONGER THAN INDICATED BY
MODELS RIGHT NOW...SO IT WILL BE INTERESTING TO SEE HOW THIS SYSTEM
EVOLVES. TO THE E AND AT THE SFC...COLD FRONT HAS DRIFTED S OF UPPER
MI. WEAKER SHORTWAVES AND RIGHT ENTRANCE OF UPPER JET EXTENDING FROM
NRN MN TO NRN QUEBEC ARE AIDING SHRA/TSTMS FROM IA/SRN MN ENE TO ERN
UPPER MI AND LWR MI. PER LATEST SPC ANALYSIS NRN EDGE OF INSTABILITY
(MLCAPES EXCEEDING 100J/KG) ONLY EXTENDS AS FAR N AS NEAR KMNM AND
THEN E ACROSS NRN LAKE MI. THUS...NO THUNDER HAS BEEN NOTED IN UPPER
MI THIS AFTN.
RIGHT ENTRANCE OF A LESS WELL-DEFINED WITH TIME UPPER JET WILL POSE
SOME RISK FOR GENERATING -SHRA AT TIMES TONIGHT TO THE N OF THE COLD
FRONT WHICH WILL BECOME NEARLY STATIONARY. THERE MAY BE A SUBTLE
SHORTWAVE UPSTREAM AS WELL WHICH COULD AID -SHRA DEVELOPMENT FARTHER
N PER ECWMF...BUT STAYED CLOSE TO THE MULTI-MODEL CONSENSUS IN
CARRYING SCHC POPS FOR AT LEAST SOME PORTION OF THE NIGHT OVER
ROUGHLY THE SE HALF OF THE FCST AREA. CHC POPS WERE CONFINED TO THE
FAR SCNTRL...AND ALSO SE CLOSE TO LAKE MI THIS EVENING. NOT
EXPECTING ANY TSTMS. MAY SEE SOME PATCHY FOG OVERNIGHT.
ON TUE...SFC LOW PRES ORGANIZES OVER THE PLAINS AND REACHES NW IA
LATE IN THE DAY IN RESPONSE TO THE STRONG SHORTWAVE MOVING OUT OVER
THE PLAINS. STRENGTHENING DEEP LAYER FORCING AND STRONG MOISTURE
TRANSPORT AHEAD OF FEATURE WILL SPREAD OVER MN AND THEN TOWARD NW
WI/WRN LAKE SUPERIOR/WRN UPPER MI LATE IN THE AFTN...RESULTING IN AN
INCREASING AREA OF MDT/HVY RAIN AND EMBEDDED THUNDER ORGANIZING TO
THE W AND SW. LOOKS LIKE MUCH OF THIS PCPN WILL HOLD OFF UNTIL TUE
NIGHT. AS FRONT TO THE S BEGINS TO MOVE BACK TO THE N AS A WARM
FRONT...PROBABLY CAN`T RULE OUT A FEW -SHRA DEVELOPING N OF THE
FRONT AS WAA BEGINS...BUT AT LEAST RIGHT NOW...POTENTIAL APPEARS
QUITE LOW. ONLY SCHC WILL BE UTILIZED EXCEPT FOR THE W IN THE AFTN
WHERE POPS WILL INCREASE THRU THE CHC CATEGORY.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 339 AM EDT TUE AUG 18 2015
BY 12Z WED AN INTENSIFYING LOW WILL BE APPROACHING OR OVER THE WRN
CWA. THE 00Z/18 GFS HAS COME INTO GOOD AGREEMENT WITH THE 12Z/17
ECMWF IN DEEPENING THE SFC LOW TO 993-995MB AS THE SYSTEM CLOSES OFF
OVER WRN LAKE SUPERIOR WED. THE NAM . BY 12Z THU THE LOW WILL BE
OCCLUDED N OF LAKE SUPERIOR AND WILL QUICKLY SHUNT N TO HUDSON BAY
BY 00Z FRI.
OVERALL EXPECTATIONS HAVE NOT CHANGED MUCH FROM THE DAY SHIFT MON. A
SURGE OF PRECIP WILL BE EXITING N WED MORNING AHEAD OF THE COLD
FRONT AND THEN DRY SLOT THAT WILL MOVE IN FROM THE SW WED LATE
MORNING/AFTERNOON. COULD SEE SOME STRONG TO POSSIBLY SEVERE STORMS
ALONG THE COLD FRONT AS EFFECTIVE SHEAR IS ENHANCED...BUT OTHERWISE
NOT EXPECTING SEVERE STORMS. AFTER THE DRY SLOT MOVES INTO MAINLY
THE CENTRAL AND ERN CWA...WRAP AROUND PRECIP/MOISTURE WILL MOVE INTO
WRN UPPER MI. THE WRAP AROUND PRECIP WILL SPREAD TO NRN AND WRN
UPPER MI WED NIGHT AND CONTINUE THROUGH MOST OF THU. WED LOOKS WINDY
WITH S-SW WINDS GUSTING TO 25-35 MPH. WINDS THU WILL BE SIMILAR
STRENGTH OF WED...BUT OUT OF THE W.
FRI AND SAT LOOK DRY WITH SW FLOW ALONG AND A SFC HIGH OVER MUCH OF
THE ERN CONUS. HOWEVER...MODELS CONTINUE TO INDICATE THAT ANOTHER
STORM SYSTEM COULD BRING PRECIP SUN INTO MON...BUT DETAILS REMAIN
UNCLEAR AT THIS TIME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 125 AM EDT TUE AUG 18 2015
ALTHOUGH SOME -SHRA MAY IMPACT IWD AND PERHAPS CMX LATER...THERE
SHOULD BE ENUF LLVL DRY AIR TO MAINTAIN VFR CONDITIONS. AT SAW...AN
UPSLOPE NE FLOW CLOSER TO STALLED FNT JUST TO THE SE OF UPR MI IN
THE PRESENCE OF NOCTURNAL COOLING WL RESULT IN A DEVELOPMENT OF MVFR
CONDITIONS FOR A TIME THIS MRNG BEFORE DAYTIME HEATING BRINGS A
RETURN OF VFR WX FOR A SHORT TIME. LOWER MVFR CIGS WL RETURN TO THAT
SITE ALONG WITH THE CHC FOR SOME -SHRA LATE IN THE DAY AS THE
STALLED FNT BEGINS MOVING TO THE N. SOME -SHRA WL RETURN TO IWD AS
WELL...BUT DOWNSLOPE NATURE OF THE LLVL WIND THERE SHOULD MAINTAIN
VFR CONDITIONS AT THE ONSET OF ANY PCPN. A STRENGTHENING ESE FLOW
AHEAD OF DEEPENING LO PRES IN THE PLAINS WL BRING A RETURN OF MORE
WDSPRD -RA/MVFR CONDITIONS IN THE EVNG. IFR CONDITIONS WL BE LIKELY
AFTER THE END OF THIS CURRENT TAF PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 443 PM EDT MON AUG 17 2015
HIGH PRES STRETCHING FROM SOUTHERN MANITOBA THROUGH JAMES BAY WILL
EXTEND A RIDGE INTO THE UPPER LAKES THRU TUE MORNING...RESULTING IN
LIGHT WINDS UNDER 15KT ACROSS LAKE SUPERIOR THRU TUE MORNING.
THEN...AS LOW PRES ORGANIZES AND STRENGTHENS OVER THE PLAINS
TUE...NE WINDS WILL BEGIN TO RAMP UP...ESPECIALLY OVER WRN LAKE
SUPERIOR WHERE GUSTS SHOULD REACH 25-30KT LATE AFTN/EARLY EVENING.
THIS LOW WILL BECOME UNSEASONABLY DEEP FOR AUG AS IT LIFTS ACROSS
FAR WRN LAKE SUPERIOR WED AFTN. 20-30KT WINDS ARE EXPECTED OVER MUCH
OF THE LAKE TUE NIGHT INTO WED. MAY SEE GALE FORCE GUSTS OVER FAR
WRN LAKE SUPERIOR IN THE NE WINDS AHEAD OF THE LOW TUE NIGHT AND
THEN IN THE WESTERLY WINDS ACROSS MAINLY CENTRAL LAKE SUPERIOR ON
THU AS THE LOW LIFTS N OF THE AREA. WINDS WILL DIMINISH TO UNDER
20KT FRI...AND THEN BEGIN TO INCREASE AGAIN ON SAT AHEAD OF THE NEXT
COLD FRONT MOVING OUT ACROSS THE PLAINS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...ROLFSON
LONG TERM...TITUS
AVIATION...KC
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS GAYLORD MI
328 AM EDT TUE AUG 18 2015
.NEAR TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 328 AM EDT TUE AUG 18 2015
HIGH IMPACT WEATHER POTENTIAL...NON-SEVERE THUNDERSTORMS TODAY AND
TONIGHT.
DIFFUSE COLD FRONT RESTS ROUGHLY FROM OSC TO MBL. THIS FRONT IS
STALLING OUT...AS LEE CYCLOGENESIS GETS UNDERWAY IN THE CENTRAL
HIGH PLAINS. SOME SHRA ARE SEEN OVER CENTRAL/NORTHERN LAKE MI AND
SURROUNDING AREAS. A FEW SHRA HAVE ALSO RECENTLY DEVELOPED JUST SW
OF LAN. NO THUNDER LEFT IN OUR NECK OF THE WOODS. THE FRONT WILL
WOBBLE ACROSS CENTRAL/NORTHERN LOWER MI OVER THE NEXT 24
HOURS...AS HEATING/CONVECTION/SOUTHERLY FLOW WAXES AND WANES.
PRECIP TRENDS ARE THE MAIN CONCERN.
TODAY...A POTENT SHORTWAVE WILL DIG FROM THE NORTHERN TO CENTRAL
HIGH PLAINS TODAY. IN RESPONSE...PRESSURES WILL RAPIDLY FALL IN THE
CENTRAL PLAINS. BY MID-EVENING...A SUB-1000MB LOW WILL BE MOVING
INTO NW IOWA. SOUTHERLY 1000-850MB FLOW INTO LOWER MI WILL INCREASE
TO SOME DEGREE...THOUGH THE TIGHTEST PRESSURE GRADIENT WILL REMAIN
TO OUR WEST THRU 00Z. STILL...THAT AND DIURNAL HEATING/MIXING WILL
TEND TO PUSH THE FRONT NORTH. HOWEVER...PRECIP AND SUBSEQUENT COLD-
POOL GENERATION NORTH OF THE FRONT WILL WORK TO SUPPRESS ANY
NORTHWARD MOVEMENT. THE NAM WANTS TO PUSH THE FRONT QUICKLY NORTH IN
THE 1ST HALF OF THE DAY...AN INTERNALLY INCONSISTENT APPROACH SINCE
IT IS ALSO AMONG THE WETTEST SOLUTIONS NORTH OF THE FRONT THIS
MORNING. THE RAP OFFERS A BETTER ALTERNATIVE IN THE NEAR-TERM...WITH
THE FRONT REACHING A MANTON-HARRISVILLE LINE BY MIDDAY...BEFORE
GETTING ABRUPTLY SHOVED SOUTHWARD AGAIN AS PRECIP BECOMES MORE
EXPANSIVE.
SPEAKING OF WHICH...THERE ARE A PAIR OF SHORTWAVES MOVING EAST
TOWARD THE LAKES REGION EARLY THIS MORNING...ONE IN W CENTRAL WI AND
THE 2ND IN NW IL. THESE WILL BOTH ACT TO PROVIDE FORCING FOR ASCENT
JUST AFTER SUNRISE IN WESTERN SECTIONS. HOWEVER...AT THIS TIME OF
DAY NEITHER HAS MUCH IN THE WAY OF INSTABILITY TO WORK WITH. NOTE
THAT ACTIVITY MOVING ENE OUT OF CHICAGO IS FIZZLING RAPIDLY OVER
SOUTHERN LAKE MI. GENERALLY THINK THAT...THRU 10AM...THE MAIN PRECIP
CHANCES WILL BE WEST OF TVC/CAD...IN EASTERN UPPER MI...AND IN
PARTS OF NE LOWER (IF DOWNSTATE ACTIVITY DEVELOPS NE-WARD AS
AGGRESSIVELY AS RECENT RAP RUNS SUGGEST).
HOWEVER...WE HAVE PLENTY OF MOISTURE (PWATS 1.5-1.7) AND SOME
FORCING FOR ASCENT AVAILABLE. SO IT WILL TAKE VERY LITTLE HEATING
(EVEN WITH CONSIDERABLE CLOUD COVER) TO PRIME THE AIRMASS FOR
CONVECTION. THIS IS ESPECIALLY THE CASE GIVEN THAT (AS OPPOSED TO
YESTERDAY) WE ACTUALLY HAVE CROSS-FRONTAL 1000-850MB FLOW.
ANTICIPATE SHRA WILL RAPIDLY EXPAND IN COVERAGE OVER NW LOWER MI
BETWEEN 10AM AND NOON. FURTHER EXPANSION ACROSS THE BULK OF NORTHERN
LOWER WILL OCCUR AS ACTIVITY CONTINUES TO PERCOLATE THRU THE
AFTERNOON. SOME OF THIS ACTIVITY WILL LEAK INTO EASTERN UPPER...BUT
THAT FAR NORTH OF THE WARM FRONT SUSPECT COVERAGE THERE WILL BE LESS
THAN THE NAM/GFS ARGUE. CONVECTION WILL BE QUICK TO TRIGGER...SO WE
WON/T REALLY GET THE CHANCE TO BUILD UP MUCH IN THE WAY OF CAPE.
MLCAPES SHOULD STAY LESS THAN 500J/KG. THIS WILL KEEP PRECIP MAINLY
AS SHRA...WITH A FEW EMBEDDED TSRA...AND NO SVR THREAT. LOCALIZED
RAINFALL AMOUNTS OF A QUARTER TO HALF AN INCH WILL BE SEEN.
WILL BE A MUGGY DAY...BUT TEMPS WILL BE SHARPLY LIMITED BY
CLOUDS/PRECIP. HIGHS WILL BE MAINLY IN THE 70S...PEAKING UP CLOSE TO
80F IN A FEW SPOTS.
TONIGHT...PRIMARY 500MB CIRCULATION CLOSES OFF AND DEEPENS AS IT
MOVES FROM EASTERN SD TO SOUTHERN MN. THE CORRESPONDING SURFACE LOW
WILL DEEPEN TO 994MB AS IT MOVES TO THE MN/WI BORDER. IN ADVANCE OF
THIS DEVELOPING CYCLONE...SOUTHERLY 850MB WINDS WILL INCREASE TO 20-
30KT. THIS WILL PUSH THE SURFACE WARM FRONT MORE EMPHATICALLY
NORTHWARD TOWARD FAR NORTHERN LOWER OR THE STRAITS REGION. CHANCES
FOR PRECIP WILL DECREASE BEHIND THE FRONT. SHRA COVERAGE WILL BE
CONSIDERABLE ACROSS THE FORECAST AREA IN THE EVENING...BUT POPS WILL
DECREASE (THOUGH NOT DISAPPEAR) SOUTH OF M-32 OVERNIGHT. IN
ADDITION...IT IS LIKELY OVERNIGHT THAT ONE OR MORE MCS/S WILL BE
MOVING EAST IN THE WARM SECTOR INTO THE SW LAKES REGION. DON/T THINK
THAT THESE WILL HOLD TOGETHER AND REACH SW SECTIONS TOWARD
DAYBREAK...BUT IT/S NOT IMPOSSIBLE. THAT/S OUR VERY LOW-END SHOT AT
ANYTHING SVR...OTHERWISE MLCAPE IS TOO LIMITED.
STILL MUGGY AND A VERY WARM NIGHT...WITH LOWS IN THE MID 60S TO
AROUND 70F.
&&
.SHORT TERM...(WEDNESDAY THROUGH THURSDAY NIGHT)
ISSUED AT 328 AM EDT TUE AUG 18 2015
LOW PRESSURE EMERGES OUT OF THE CENTRAL PLAINS TODAY THEN HEADS
NORTHEAST INTO THE NORTHERN MISSISSIPPI VALLEY WHILE DEEPENING. THE
IMPACTS FROM THIS SYSTEM WILL BE THE FOCUS OF THE FORECAST WITH THE
MAIN CHALLENGE BEING THE POTENTIAL FOR SEVERE STORMS WEDNESDAY.
WEDNESDAY...THE TRACK OF A NEGATIVELY TILTED TROUGH AND ASSOCIATED
AREA OF DEEPENING LOW PRESSURE TO OUR NORTHWEST IS EXPECTED TO LEAD
TO A SOLID AREA OF SHOWERS ACROSS EASTERN UPPER AND FAR NORTHWEST
LOWER WEDNESDAY WITH SLIGHTLY LESSER BUT MORE CONVECTIVE
SHOWER/STORM COVERAGE ACROSS SOUTHEAST ZONES. THERE IS A THREAT FOR
SEVERE STORMS...MAINLY BECAUSE OF STRONGER WINDS ALOFT (NAM 0-6KM
BULK SHEAR 30 TO 40 KNOTS WITH THE MORE BULLISH GFS A ROBUST 50 TO
55 KNOTS!). IN ADDITION TO THE STRONG WINDS ALOFT NORTHEAST LOWER
MAY ALSO GET INTO HEALTHY AMOUNTS OF INSTABILITY IF THE SUN IS ABLE
TO BREAK OUT IN THE DRY SLOT. SO NOT SURPRISINGLY...SPC HAS JUST
PLACED ALL OF NORTHERN LOWER IN A SLIGHT RISK FOR WIND AND/OR HAIL.
MODELS CONTINUE TO DIFFER ON THE FINER DETAILS OF THIS SYSTEM
INCLUDING TIMING AND STRENGTH (THOUGH BOTH THE ECMWF AND GFS ARE
TRENDING STRONGER) SO STAY TUNED FOR FURTHER UPDATES AS THIS
POSSIBLE EVENT GETS A LITTLE CLOSER. A SYSTEM THIS DEEP THIS TIME OF
THE YEAR IS A BIT UNUSUAL SO THINGS HAVE THE POTENTIAL TO GET
INTERESTING. HIGHS RANGING FROM THE MUGGY UPPER 70S NORTH TO PERHAPS
THE TOASTY UPPER 80S SOUTHEAST ZONES.
WEDNESDAY NIGHT...A FEW MORE SHOWERS (AND THUNDERSTORMS EAST) ARE
LIKELY AS THE COLD FRONT ASSOCIATED WITH THE LOW PRESSURE SYSTEM
MOVES ACROSS THE REGION (ACTUALLY IT MAY BE MORE OF AN OCCLUDED
FRONT AT THAT POINT). LOWS RANGING FROM THE UPPER 50S TO MIDDLE 60S.
THURSDAY...WRAP AROUND SHOWERS ARE POSSIBLE ACROSS EASTERN UPPER AND
FAR NORTHERN LOWER...ESPECIALLY IN THE MORNING. COOLER WITH HIGHS
ONLY IN THE UPPER 60S AND LOWER 70S.
&&
.LONG TERM...(FRIDAY THROUGH MONDAY)
ISSUED AT 328 AM EDT TUE AUG 18 2015
HIGH PRESSURE BUILDS IN FRIDAY WHICH SHOULD HOLD ON THROUGH SATURDAY
NIGHT YIELDING WARMER AND DRIER CONDITIONS. ANOTHER AREA OF LOW
PRESSURE TRACKING BY TO OUR NORTHWEST WILL THEN BRING MORE CHANCES
FOR SHOWERS AND THUNDERSTORMS SUNDAY...WITH WRAP AROUND DRIVEN
SHOWERS POSSIBLY LINGERING INTO MONDAY (MODELS ARE NOT IN AGREEMENT
HERE BUT PLENTY OF TIME TO MAKE ADJUSTMENTS). HIGHS BACK IN THE
UPPER 70S AND LOWER 80S FRIDAY THROUGH SUNDAY. COOLER AGAIN FOR
MONDAY WITH HIGHS IN THE UPPER 60S AND LOWER 70S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 143 AM EDT TUE AUG 18 2015
VARIABLE CONDITIONS THRU THE TAF PERIOD.
STALLED COLD FRONT IS LAID OUT ALONG THE M-55 CORRIDOR. THIS FRONT
WILL WOBBLE ACROSS CENTRAL AND NORTHERN LOWER MI TODAY AND
TONIGHT. CONSIDERABLE SHRA AND A FEW TSRA WILL BE SEEN NORTH OF
THE FRONT...ESPECIALLY FROM LATE MORNING TODAY THRU TONIGHT. THESE
AREAS WILL ALSO BE PRONE TO LOWERED CIGS/VSBYS...ESPECIALLY DURING
THE NIGHTS/MORNINGS. PRESENTLY APN IS LIFR WHILE OTHER SITES ARE
VFR. EXPECTED ALL SITES TO HAVE SOME RESTRICTIONS BY
DAYBREAK...SEE SOME DEGREE OF IMPROVEMENT DURING THE DAY...AND
THEN WORSEN A BIT AGAIN TOWARD MIDNIGHT TONIGHT.
WINDS WILL BE LIGHT SOUTHERLY TO EASTERLY.
&&
.MARINE...
ISSUED AT 328 AM EDT TUE AUG 18 2015
A STALLED FRONT WILL WOBBLE ACROSS CENTRAL LOWER MI TODAY...BEFORE
MOVING NORTH TONIGHT AS A WARM FRONT. SE-ERLY WINDS WILL BE LIGHT
THRU THIS EVENING...BUT INCREASE OVERNIGHT. SMALL CRAFT
ADVISORIES WILL LIKELY BE NEEDED ON SOME WATERS BY WEDNESDAY
AFTERNOON. A STRONG COLD FRONT WILL CROSS THE REGION LATE
WEDNESDAY...WITH STRONG TO POTENTIALLY SVR THUNDERSTORMS.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
NEAR TERM...JAZ
SHORT TERM...SULLIVAN
LONG TERM...SULLIVAN
AVIATION...JAZ
MARINE...JAZ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
126 AM EDT TUE AUG 18 2015
.UPDATE...
ISSUED AT 848 PM EDT MON AUG 17 2015
ADDED SOME ISOLD SHOWERS TO THE FCST FOR WRN UPR MI OVERNGT TO
ACCOUNT FOR AREA OF SHOWERS MOVING SLOWLY NE THRU NW WI AHEAD OF
DISTURBANCE IN SW MN AND UNDER COOLING CLD TOPS. POTENT SHRTWV
DIGGING INTO THE NRN PLAINS WL LIKELY CAUSE THE UPR FLOW TO BACK ENUF
TO LIFT THESE SHOWERS INTO THE WRN CWA. ONLY THE LATEST RAPID REFRESH
MODEL HAS A GOOD HANDLE ON THE LOCATION OF THE PCPN AT PRESENT TIME.
THIS MODEL SHOWS THESE SHOWERS SPREADING INTO WRN UPR MI AFTER MIDNGT
DESPITE SOME DRIER LLVL AIR THAT WL RESTRICT THE COVERAGE/INTENSITY.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 443 PM EDT MON AUG 17 2015
WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A BROAD TROF EXTENDING S
INTO THE NRN ROCKIES NRN PLAINS. POTENT LOOKING SHORTWAVE OVER SW MT
WILL GENERATE AN UNUSUALLY STRONG SFC LOW FOR AUG THAT WILL MOVE
ACROSS THE UPPER MISSISSIPPI VALLEY/UPPER GREAT LAKES TUE NIGHT/WED.
SYSTEM ON WATER VAPOR IMAGERY LOOKS STRONGER THAN INDICATED BY
MODELS RIGHT NOW...SO IT WILL BE INTERESTING TO SEE HOW THIS SYSTEM
EVOLVES. TO THE E AND AT THE SFC...COLD FRONT HAS DRIFTED S OF UPPER
MI. WEAKER SHORTWAVES AND RIGHT ENTRANCE OF UPPER JET EXTENDING FROM
NRN MN TO NRN QUEBEC ARE AIDING SHRA/TSTMS FROM IA/SRN MN ENE TO ERN
UPPER MI AND LWR MI. PER LATEST SPC ANALYSIS NRN EDGE OF INSTABILITY
(MLCAPES EXCEEDING 100J/KG) ONLY EXTENDS AS FAR N AS NEAR KMNM AND
THEN E ACROSS NRN LAKE MI. THUS...NO THUNDER HAS BEEN NOTED IN UPPER
MI THIS AFTN.
RIGHT ENTRANCE OF A LESS WELL-DEFINED WITH TIME UPPER JET WILL POSE
SOME RISK FOR GENERATING -SHRA AT TIMES TONIGHT TO THE N OF THE COLD
FRONT WHICH WILL BECOME NEARLY STATIONARY. THERE MAY BE A SUBTLE
SHORTWAVE UPSTREAM AS WELL WHICH COULD AID -SHRA DEVELOPMENT FARTHER
N PER ECWMF...BUT STAYED CLOSE TO THE MULTI-MODEL CONSENSUS IN
CARRYING SCHC POPS FOR AT LEAST SOME PORTION OF THE NIGHT OVER
ROUGHLY THE SE HALF OF THE FCST AREA. CHC POPS WERE CONFINED TO THE
FAR SCNTRL...AND ALSO SE CLOSE TO LAKE MI THIS EVENING. NOT
EXPECTING ANY TSTMS. MAY SEE SOME PATCHY FOG OVERNIGHT.
ON TUE...SFC LOW PRES ORGANIZES OVER THE PLAINS AND REACHES NW IA
LATE IN THE DAY IN RESPONSE TO THE STRONG SHORTWAVE MOVING OUT OVER
THE PLAINS. STRENGTHENING DEEP LAYER FORCING AND STRONG MOISTURE
TRANSPORT AHEAD OF FEATURE WILL SPREAD OVER MN AND THEN TOWARD NW
WI/WRN LAKE SUPERIOR/WRN UPPER MI LATE IN THE AFTN...RESULTING IN AN
INCREASING AREA OF MDT/HVY RAIN AND EMBEDDED THUNDER ORGANIZING TO
THE W AND SW. LOOKS LIKE MUCH OF THIS PCPN WILL HOLD OFF UNTIL TUE
NIGHT. AS FRONT TO THE S BEGINS TO MOVE BACK TO THE N AS A WARM
FRONT...PROBABLY CAN`T RULE OUT A FEW -SHRA DEVELOPING N OF THE
FRONT AS WAA BEGINS...BUT AT LEAST RIGHT NOW...POTENTIAL APPEARS
QUITE LOW. ONLY SCHC WILL BE UTILIZED EXCEPT FOR THE W IN THE AFTN
WHERE POPS WILL INCREASE THRU THE CHC CATEGORY.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 332 PM EDT MON AUG 17 2015
A LOW INTENSIFYING ALONG THE MINNESOTA AND IOWA BORDER AT THE START
OF THE PERIOD WILL BRING UNSETTLED WEATHER FOR THE UPPER GREAT
LAKES REGION THROUGH THE FIRST HALF OF THE LONG TERM FORECAST. THIS
LOW WILL BE AROUND 998MB AND WILL BE LIFTING TO THE NORTH TUESDAY
NIGHT INTO WEDNESDAY (WHILE STRENGTHENING TO 993MB) IN RESPONSE TO
A SHORTWAVE ROUNDING THE BASE OF THE UPPER TROUGH IN THE NORTHERN
PLAINS. THERE ARE SOME DIFFERENCES IN THE MODELS ON HOW FAST THIS
LOW (ANOMALOUS FOR MID-LATE AUGUST) WILL MOVE NORTH THROUGH THE
DULUTH AREA AND ACROSS WESTERN LAKE SUPERIOR ON WEDNESDAY...BUT WITH
THE RECENT TRENDS HEADING TOWARDS A SLOWER DEPARTURE FROM LAKE
SUPERIOR...WILL FOLLOW THAT IDEA IN THE FORECAST.
EXPECT A FEW WAVES OF PRECIPITATION TO MOVE THROUGH THE U.P. WITH
THIS LOW...BUT UNFORTUNATELY THE TRACK WILL NOT PROMOTE A
MUCH NEEDED WIDESPREAD AND SOAKING RAIN FOR MOST OF THE AREA. THE
FIRST WAVE WILL ARRIVE LATE TOMORROW AFTERNOON AND INTO TOMORROW
NIGHT AS BROAD MID LEVEL WARM AIR ADVECTION SWEEPS NORTH ACROSS THE
AREA. THE BEST ASCENT WILL BE TO THE WEST-NORTHWEST OF THE AREA AND
TOWARDS THE MINNESOTA ARROWHEAD...BUT THE WESTERN U.P. COULD BE
BRUSHED BY SOME OF THE STRONGER AREAS OF RAIN. OTHERWISE...EXPECT
RAINFALL AMOUNTS TO SLOWLY DIMINISH FROM AROUND AN INCH OVER THE FAR
WEST TO A HALF AN INCH OR LESS TO THE EAST OF NEWBERRY.
THE NEXT WAVE WILL PUSH NORTH-NORTHEAST THROUGH THE CWA ON
WEDNESDAY MORNING AND PRODUCE AN AREA OF SCATTERED/NUMEROUS SHOWERS
AND MAYBE A FEW THUNDERSTORMS AS IT MOVES THROUGH THE AREA. WILL
SHOW A PERIOD OF THUNDER CHANCES ALONG THAT FRONT AS IT MOVES
THROUGH...TIED TO THE LOWER SHOWALTER VALUES AND MUCAPE VALUES
RISING BETWEEN 500-750 J/KG RIGHT ALONG THE FRONT. EFFECTIVE SHEAR
VALUES LOOK TO BE FAIRLY LOW...SO THAT SHOULD ELIMINATE MUCH OF THE
SEVERE THREAT...EXCEPT FOR AREAS RIGHT ALONG THE COLD FRONT WHICH
WILL TRY TO PUSH EFFECTIVE SHEAR VALUES UP TOWARDS 30KTS. AS THIS
FRONT MOVES NORTH THROUGH THE DAY AND THE DRY SLOT MOVES OVER THE
AREA ALOFT...HAVE TRENDED POPS DOWN OVER THE CENTRAL AND EAST
THROUGH THE DAY...WITH ONLY SLIGHT CHANCES IN THE AFTERNOON
(ALTHOUGH THAT MAY BE TOO HIGH). WRAP AROUND RAIN WILL THEN ARRIVE
OVER THE WEST LATE WEDNESDAY AFTERNOON AND CONTINUE INTO WEDNESDAY
NIGHT. EXPECT THE SCATTERED/NUMEROUS SHOWERS TO STAY MORE OVER THE
WESTERN U.P. BUT DID SPREAD CHANCES EAST OVERNIGHT INTO THURSDAY FOR
MUCH OF THE REST OF THE U.P. WINDS WILL ALSO BE ON THE INCREASE
LATE WEDNESDAY NIGHT INTO THURSDAY MORNING BEHIND THE LOW DUE TO
THE COMBINED PRESSURE RISE AND STEEPENING LOW LEVEL LAPSE RATES
TOWARDS 8-9 C/KM BETWEEN THE SURFACE AND 900MB. THAT WILL LIKELY
PRODUCE GUSTS TO 30KTS OVER WESTERN/CENTRAL LAKE SUPERIOR AND
20-30KTS OVER MOST LAND AREAS.
CONDITIONS WILL IMPROVE THURSDAY NIGHT AS A HIGH PRESSURE RIDGE
BUILDS INTO THE AREA. THIS WILL BRING DECREASING CLOUDS AND WINDS
THROUGH THE NIGHT AND SHOULD LEAD TO A NICE DAY ACROSS THE AREA ON
FRIDAY. THE SUNSHINE WILL BRING HIGHS BACK UP TO NORMAL OR SLIGHTLY
ABOVE NORMAL VALUES ON FRIDAY AND EXPECT TEMPERATURES A TOUCH
WARMER ON SATURDAY (AROUND 80) WITH THE SOUTHERLY FLOW.
ANOTHER STRONG UPPER TROUGH WILL MOVE INTO THE NORTHERN PLAINS ON
SATURDAY AND MOVE THROUGH THE AREA SUNDAY INTO SUNDAY NIGHT. WILL
CONTINUE TO SHOW HIGH CHANCE AND LOW END LIKELY POPS AS THAT MOVES
THROUGH THE AREA BEFORE SLOWLY DEPARTING ON MONDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 125 AM EDT TUE AUG 18 2015
ALTHOUGH SOME -SHRA MAY IMPACT IWD AND PERHAPS CMX LATER...THERE
SHOULD BE ENUF LLVL DRY AIR TO MAINTAIN VFR CONDITIONS. AT SAW...AN
UPSLOPE NE FLOW CLOSER TO STALLED FNT JUST TO THE SE OF UPR MI IN
THE PRESENCE OF NOCTURNAL COOLING WL RESULT IN A DEVELOPMENT OF MVFR
CONDITIONS FOR A TIME THIS MRNG BEFORE DAYTIME HEATING BRINGS A
RETURN OF VFR WX FOR A SHORT TIME. LOWER MVFR CIGS WL RETURN TO THAT
SITE ALONG WITH THE CHC FOR SOME -SHRA LATE IN THE DAY AS THE
STALLED FNT BEGINS MOVING TO THE N. SOME -SHRA WL RETURN TO IWD AS
WELL...BUT DOWNSLOPE NATURE OF THE LLVL WIND THERE SHOULD MAINTAIN
VFR CONDITIONS AT THE ONSET OF ANY PCPN. A STRENGTHENING ESE FLOW
AHEAD OF DEEPENING LO PRES IN THE PLAINS WL BRING A RETURN OF MORE
WDSPRD -RA/MVFR CONDITIONS IN THE EVNG. IFR CONDITIONS WL BE LIKELY
AFTER THE END OF THIS CURRENT TAF PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 443 PM EDT MON AUG 17 2015
HIGH PRES STRETCHING FROM SOUTHERN MANITOBA THROUGH JAMES BAY WILL
EXTEND A RIDGE INTO THE UPPER LAKES THRU TUE MORNING...RESULTING IN
LIGHT WINDS UNDER 15KT ACROSS LAKE SUPERIOR THRU TUE MORNING.
THEN...AS LOW PRES ORGANIZES AND STRENGTHENS OVER THE PLAINS
TUE...NE WINDS WILL BEGIN TO RAMP UP...ESPECIALLY OVER WRN LAKE
SUPERIOR WHERE GUSTS SHOULD REACH 25-30KT LATE AFTN/EARLY EVENING.
THIS LOW WILL BECOME UNSEASONABLY DEEP FOR AUG AS IT LIFTS ACROSS
FAR WRN LAKE SUPERIOR WED AFTN. 20-30KT WINDS ARE EXPECTED OVER MUCH
OF THE LAKE TUE NIGHT INTO WED. MAY SEE GALE FORCE GUSTS OVER FAR
WRN LAKE SUPERIOR IN THE NE WINDS AHEAD OF THE LOW TUE NIGHT AND
THEN IN THE WESTERLY WINDS ACROSS MAINLY CENTRAL LAKE SUPERIOR ON
THU AS THE LOW LIFTS N OF THE AREA. WINDS WILL DIMINISH TO UNDER
20KT FRI...AND THEN BEGIN TO INCREASE AGAIN ON SAT AHEAD OF THE NEXT
COLD FRONT MOVING OUT ACROSS THE PLAINS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...KC
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
1136 PM MDT MON AUG 17 2015
.AVIATION...
06Z TAF CYCLE
A DISTURBANCE ALOFT AND ASSOCIATED JET STREAK OF HIGHER WIND
SPEEDS ALOFT ARE PUSHING INTO COLORADO AND NORTHERN NEW MEXICO
LATE THIS EVENING. THIS WILL CONTINUE TO PRODUCE SOME ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS...MOSTLY ACROSS NORTH CENTRAL
TO EASTERN SECTIONS OF NEW MEXICO. THIS ACTIVITY WILL MOVE FAIRLY
QUICKLY AT 20 TO 30 KT WITH BRIEF DOWNPOURS AND SOME ERRATIC
GUSTY WINDS TO 35 KT POSSIBLE. MOST OF THE ACTIVITY SHOULD SUBSIDE
BEFORE 18/1200UTC. ANY STORM ACTIVITY DURING THE DAYTIME TUESDAY
WILL BE FROM A COLD FRONT ENTERING NORTHEASTERN NEW MEXICO. WINDS
WILL SHIFT AND BECOME GUSTY FROM THE NORTHEAST TO EAST BEHIND THIS
FRONT WHILE REMAINING AREAS GENERALLY OBSERVE GUSTY NORTHWEST
WINDS OF 15 TO 30KT.
52
&&
.PREV DISCUSSION...911 PM MDT MON AUG 17 2015...
.UPDATE...
STRONG TO SEVERE STORMS HAVE DIMINISHED OR MOVED OUT OF THE CWA.
CONSEQUENTLY REMOVED MENTION FROM WX GRID AND DECREASED POPS FOR
THE EVENING...SHORT TERM MODELS NOT AS BULLISH AS THEY WERE A FEW
HOURS AGO WITH HOLDING ONTO PRECIPITATION IN THE EAST AFTER
MIDNIGHT. UPDATED ZFP ALREADY TRANSMITTED.
&&
.PREV DISCUSSION...341 PM MDT MON AUG 17 2015...
.SYNOPSIS...
SEVERE THUNDERSTORMS WILL REMAIN POSSIBLE THROUGH THE EVENING
ACROSS MUCH OF NORTHEAST NEW MEXICO. LARGE HAIL AND DAMAGING WINDS
WILL BE THE MAIN THREATS. THEREAFTER...A DRYING TREND WILL
COMMENCE. MUCH FEWER STORMS ARE EXPECTED TUESDAY THROUGH THURSDAY.
A BACK DOOR FRONT ON TUESDAY NIGHT WILL RESULT IN FALL LIKE
TEMPERATURES ON WEDNESDAY ACROSS THE EASTERN PLAINS. LATER IN THE
WEEK...A SLOW INCREASE IN THUNDERSTORM ACTIVITY IS POSSIBLE.
&&
.DISCUSSION...
SEVERE WEATHER REMAINS POSSIBLE THROUGH THIS EVENING ACROSS THE
NORTHEAST QUADRANT OF NM. 35 TO 40KTS OF BULK SHEAR AND CAPE UP TO
2500 J/KG PER LAPS ANALYSIS WILL PROVIDE AN ENVIRONMENT VERY
SUITABLE FOR STORMS TO BECOME SEVERE AS THEY MOVE OFF THE HIGHER
TERRAIN INTO THE NE PLAINS. A JET MAX WILL ALSO AID IN TSTM
DEVELOPMENT AND FOCUS ACTIVITY ACROSS THE NE. LARGE HAIL AND
DAMAGING WIND GUSTS WILL BE THE MAIN THREAT WITH THIS ACTIVITY.
THE LATEST HRRR SHOWS MOST OF THIS INITIAL ROUND OF ACTIVITY
EXITING NM BY MID EVENING...BUT ANOTHER ROUND OF STORMS MAY
DEVELOP LATER THANKS TO OUTFLOW BOUNDARIES MOVING IN FROM SE CO.
THE UPPER LEVEL TROUGH WILL CROSS THE CENTRAL ROCKIES TONIGHT AND
THE ASSOCIATED PACIFIC FRONT WILL SLIDE THROUGH CENTRAL AND
WESTERN NM. MUCH DRIER AIR BEHIND THE TROUGH AND BREEZY WINDS WILL
MIX DOWN TO THE SURFACE...RESULTING IN SOME OF THE LOWEST
DEWPOINTS WE HAVE SEEN ACROSS THE NW SINCE THE SPRING.
MEANWHILE...THE BACK DOOR SEGMENT OF THE FRONT WILL SLIDE DOWN THE
PLAINS. A FEW STORMS MAY DEVELOP ALONG THE FRONT AND ALONG THE
EAST SLOPES OF THE SANGRES...BUT THE DEEP LAYER OF DRIER AIR ALOFT
WILL LIMIT COVERAGE SIGNIFICANTLY. THE FRONT SHOULD PUSH THRU THE
GAPS OF THE CENTRAL MTN CHAIN TUESDAY NIGHT...BUT THE MOISTURE IT
BRINGS WITH IT SHOULD QUICKLY MIX OUT ON WEDNESDAY WITHIN THE RGV.
ON WEDNESDAY...SOME OF THE MOISTURE ACROSS THE PLAINS WILL ALSO
MIX OUT. CONTINUE LOW LEVEL SOUTHEASTERLY FLOW...HOWEVER...MAY
YIELD A STRAY SHOWER OR TSTM ALONG THE CENTRAL MTN CHAIN...BUT
CONFIDENCE IS PRETTY LOW. THE BIGGER STORY WILL BE THE MUCH COOLER
TEMPS ACROSS THE EAST IN THE WAKE OF THE BACK DOOR FRONT. MOST
AREAS WILL STRUGGLE TO REACH 80.
ANOTHER WEAK WAVE LOOKS TO CROSS NM ON THURSDAY...BUT CONTINUED
DRY AIR OVER THE STATE WILL CONTINUE TO LIMIT TSTM ACTIVITY. SE
PORTIONS OF THE CWA MAY BE FAVORED FOR AN ISOLATED STORM WHERE
BETTER LOW LEVEL MOISTURE EXISTS.
CONFIDENCE REMAINS LOW IN THE FORECAST FRIDAY AND BEYOND. MODELS
CONTINUE TO SUGGEST SOME MOISTURE WILL SEEP UP INTO NM AND WE WILL
SEE A GRADUAL INCREASE IN TSTM ACTIVITY. OF MORE CERTAINTY LOOKS
TO BE ANOTHER BACK DOOR COLD FRONT SLIDING DOWN THE PLAINS OVER
THE WEEKEND WHICH WILL HELP TO MOISTEN UP LOW LEVELS...BUT THE
PARENT TROUGH MAY BRING DRIER AIR OVER NORTHERN NM ONCE AGAIN.
STAY TUNED.
34
&&
.FIRE WEATHER...
FAIRLY ACTIVE AND VIGOROUS BATCH OF SHOWERS AND STORMS AS OF MID
AFTN STRETCHING FROM THE SANGRE DE CRISTOS AND NE HIGHLANDS AND
PLAINS SOUTH AND SOUTHWESTWARD TO THE CENTRAL HIGHLANDS AND MID TO
LOWER RIO GRANDE VALLEY. A FEW HAVE ALREADY BECOME SEVERE ACROSS
THE NORTHERN PORTION OF THIS AREA. THIS ACTIVITY WILL EXPAND SOME
ACROSS THE EASTERN PLAINS THROUGH THE EVE. MOST OF THE NW THIRD OF
THE STATE WILL BE DRY THROUGH THE EVENING AND THIS DRYING TREND
WILL EXPAND SOUTH AND EAST OVER THE NEXT 24 TO 48 HOURS IN THE
WAKE OF A SIGNIFICANT AND EARLIER THAN USUAL MID TO UPPER LOW
PRESSURE TROUGH. ACCOMPANYING AND IN THE WAKE OF THE TROUGH WILL
BE A STRENGTHENING NORTHWEST FLOW ALOFT OVER CENTRAL AND NORTHERN
NEW MEXICO THAT WILL USHER THE MUCH DRIER AIR MASS FROM NW TO SE.
WEST AND NW NEAR SFC WINDS WILL BE PERKING UP SIGNIFICANTLY ACROSS
MUCH OF NORTHERN NM TUE IN RESPONSE TO THE INCREASED NW FLOW ALOFT.
SOME SPOTTY AND LOCALIZED CRITICAL FIRE WEATHER CONDITIONS WILL BE
POSSIBLE OVER AREAS MAINLY BETWEEN THE NW PLATEAU AND THE HIGH
TERRAIN OF RIO ARRIBA AND LOS ALAMOS COUNTIES. THESE CONDITIONS ARE
NOT EXPECTED TO BE WIDESPREAD AND GIVEN CURRENT FUEL STATUS AND
LOW/MODERATE FIRE DANGER...FIRE WEATHER HIGHLIGHTS WILL NOT BE
ISSUED. STILL MIN RH WILL REALLY CRATER OCCUR ON TUE. SURFACE DEW
POINTS WILL DROP INTO THE 20S AND 30S ACROSS THE NW THIRD TO
NEARLY HALF OF FCST AREA TUE AFTN.
DAYTIME TEMPS WILL LOWER BY 5 TO 15 DEGREES...THE MOST EAST...WED IN
WAKE OF AN ASSOCIATED PACIFIC FRONT AS WELL AS A BACKDOOR SEGMENT OF
THE FRONTAL SYSTEM. THE LATTER WILL REACH NE AREAS ON TUESDAY...WITH
THE MAIN SOUTHWARD SURGE TUE NIGHT INTO WED. THIS SHOULD BRING AT
LEAST A MODERATE EAST GAP WIND INTO PORTIONS OF THE RIO GRANDE
VALLEY AND THUS DEW POINTS WILL RECOVER EAST OF THE CENTRAL
MOUNTAIN CHAIN AND TO A LESSER DEGREE INTO THE RIO GRANDE VALLEY FOR
WED.
THE WED TO THU PERIOD SHOULD FEATURE LITTLE OR NO THUNDER IN THE
FCST AREA. EXPECT WARMING TEMPERATURES AND SLIGHT MOISTURE INCREASE
FOR LATE WEEK AS HIGH PRESSURE BUILDS AND THE AIR MASS GRADUALLY
RECOVERS. EXCELLENT VENTILATION THE NEXT 3 TO 5 DAYS...EXCEPT THE
EAST HALF ON WED MAY ONLY REACH FAIR TO GOOD LVLS.
43
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS RALEIGH NC
235 AM EDT TUE AUG 18 2015
.SYNOPSIS...SOUTHWEST FLOW WILL TRANSPORT MOISTURE-RICH AIR INTO
CENTRAL NORTH CAROLINA. MEANWHILE A SERIES OF UPPER LEVEL
DISTURBANCES EMBEDDED IN THIS FLOW WILL MOVE ACROSS THE AREA. THE
COMBINATION OF THESE FEATURES WILL RESULT IN ENHANCED RAIN CHANCES
THROUGH MUCH OF THE WEEK.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 235 AM TUESDAY...
LATEST MESOANALYSIS SHOWS THAT MOISTURE IS INCREASING FROM THE SOUTH
AS EXPECTED...AS THE PATTERN CONTINUES TO EVOLVE AND FLOW BECOMES
MORE UNIFORM FROM THE SOUTH AND SOUTHWEST. LATEST WATER VAPOR SHOWS
THE OLD CLOSED LOW OVER THE LOWER OH VALLEY HAS OPENED UP AND LIFTED
NORTH UP OVER INDIANA...AND HAS BECOME EMBEDDED WITHIN THE LONGWAVE
TROUGH DEEPENING OVER THE MIDDLE OF THE COUNTRY. EXTENDING SOUTH
FROM THIS WAVE IS A SHEAR AXIS THAT EXTENDS ACROSS THE APPALACHIANS
AND INTO UPSTATE SC. THIS FEATURE...COUPLED WITH THE NORTHWARD SURGE
OF MOISTURE...HAS PROVIDED THE MECHANISM AND FORCING FOR THE CURRENT
AREA OF LIGHT RAIN NOW MOVING ACROSS THE TRIAD REGION SOUTH TO THE
CHARLOTTE AREA. THE AREA OF RAIN ACROSS UPSTATE SC IS ALONG AND
AHEAD OF THE SHORTWAVE AT THE TAIL END OF THE AFOREMENTIONED SHEAR
AXIS. THESE FEATURES ARE PROGGED TO LIFT TO THE ENE TODAY...AND
LATEST CAMS INCLUDING THE HRRR WELL-DEPICT THESE FEATURES AND
SUGGESTS THAT THE TWO AREAS OF LIGHT RAIN WILL SPREAD EAST ACROSS
CENTRAL NC THIS MORNING INTO THE EARLY AFTERNOON. GIVEN THE
EXTENSIVE CLOUD COVER AND LIMITED INSTABILITY...WE EXPECT THE PRECIP
TO REMAIN STRATIFORM AND MAINLY LIGHT THROUGH THE MORNING HOURS.
THEN AS THE SHEAR AXIS BEGINS TO LIFT TO OUR NORTH...WE MAY BEGIN TO
SEE BREAKS IN THE CLOUDS AND SOME SUNSHINE LATE THIS MORNING AND
DURING THE AFTERNOON...WHICH WILL ALLOW FOR THE REMAINING PRECIP TO
TRANSITION TO MORE CONVECTIVE AND SCATTERED IN NATURE...WITH PERHAPS
SOME THUNDER AND LOCALIZED HEAVY DOWNPOURS. GIVEN THE HIGH PWAT
ENVIRONMENT AND SLOW MOVEMENT...LOCALIZED POOR DRAINAGE FLOODING
WILL BE THE PRIMARY IMPACT CONCERN WITH THE HEAVIER CELLS THIS
AFTERNOON. AS FOR TEMPS...MAV AND MET CONTINUE TO EXHIBIT A WIDE
SPREAD IN FORECAST VALUES FOR TODAY...WITH THE COOLER MAV SUGGESTING
READINGS RANGING FROM THE UPPER 70S NW TO MID 80S S/SE...WHILE THE
NAM IS SEVERAL DEGREES WARMER ACROSS THE TRIAD AND TRIANGLE REGIONS.
WITH THE CLOUD AND PRECIP COVERAGE THE PRIMARY FACTORS...WE FEEL
THAT A BLEND OF THE TWO IS WARRANTED BECAUSE SOME SUNSHINE IS
EXPECTED THIS AFTERNOON...ESP SOUTH OF HWY 64. THUS...HIGHS AROUND
80 ACROSS THE TRIAD...LOW-MID 80S TRIANGLE...MID 80S S OF HWY 64.
THE CHANCE FOR SCATTERED SHOWERS AND ISOLD TSTMS WILL CONTINUE
TONIGHT AS SEVERAL WEAK DISTURBANCES EMBEDDED IN THE SW FLOW
TRAVERSE THE AREA. LOWS WITHIN A COUPLE DEGREES OF 70.
&&
.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
AS OF 235 AM TUESDAY...
LITTLE CHANGE IN THE PATTERN...WHICH WILL FEATURE A LONGWAVE TROUGH
OVER THE MIDDLE OF THE COUNTRY AND A RIDGE EXTENDING ACROSS FL INTO
THE GOMEX. SW FLOW BETWEEN THESE FEATURES ACROSS THE SOUTHEAST
STATES WILL KEEP THE FLOW OF MOISTURE-RICH AIR INTO OUR AREA GOING.
THAT COUPLED WITH A SERIES OF DISTURBANCES EMBEDDED WITHIN THE SW
FLOW WILL MEAN THE RISK FOR SCATTERED SHOWERS AND TSTMS WILL
CONTINUE ACROSS OUR AREA THROUGH THE PERIOD. THE SCATTERED NATURE OF
THE SHOWERS AND TSTMS MEANS IT WON`T BE RAINING DURING THE ENTIRE
TIME...BUT IT WORTH POINTING OUT THAT ANY OF THE HEAVIER CELLS WILL
BE CAPABLE OF PRODUCING HEAVY DOWNPOURS AND LOCALIZED POOR DRAINING
FLOODING. WITH ENHANCED CLOUDINESS AND RAIN CHANCES...TEMPS SHOULD
REMAIN A DEGREE OR TWO BELOW NORMAL. HIGHS FROM THE MID 80S NORTH
TO UPPER 80S SOUTH. LOWS WEDNESDAY NIGHT 70-73.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 235 AM TUESDAY...
FOR THE PERIOD THURSDAY AND THURSDAY NIGHT...500MB HEIGHTS ARE
FORECAST BY BOTH THE NAM AND THE GFS TO RISE THURSDAY INTO THURSDAY
NIGHT. THIS SHOULD SERVE TO BOTH SLOW AND WEAKEN THE SURFACE FRONT
MOVING INTO CENTRAL NORTH CAROLINA. WIND SPEEDS GENERALLY LIGHTEN
THROUGH THE COLUMN WHICH SHOULD LIMIT LOW-LEVEL CONVERGENCE AS WELL
AS ANY DIFFLUENCE ALOFT. 850MB LIFT IS WEAK...BEST THURSDAY NIGHT
COMPARED TO DURING THE DAY THURSDAY...WHEN THE GFS IS ACTUALLY DRY
OVER MUCH OF CENTRAL NORTH CAROLINA. PRECIPITABLE WATER VALUES...
THOUGH...ARE STILL FORECAST IN VICINITY OF TWO INCHES WITH HIGH K
INDICES AND DECENT 850MB THETA-E VALUES. THE GFS ALSO FORECASTS A
MODEST 700MB SHORTWAVE MOVING THROUGH CENTRAL NORTH CAROLINA DURING
THE DAY AND EVENING...WITH PRONOUNCED 700MB NVA LATE THURSDAY NIGHT.
CONSIDERING THE AVAILABLE MOISTURE...MODEST INSTABILITY EVEN ON THE
GFS WITH MUCAPE OF 500-1000J/KG...AND THE NAM FORECAST OF GREATER
LOW-LEVEL CONVERGENCE WITH MORE OF A SOUTHERLY SURFACE WIND AS
OPPOSED TO THE MORE WESTERLY GFS FORECAST...PRUDENT TO CONTINUE AT
LEAST A CHANCE OF SHOWERS AND A THUNDERSTORM OR TWO FOR THIS PART OF
THE FORECAST. THIS DESPITE THE SINGLE-DIGIT MAV MOS POPS AT KRDU AND
KFAY FOR THE DAY THURSDAY. HIGHS FOR THURSDAY ARE A LITTLE TOUGH TO
GAUGE ANTICIPATING CONSIDERABLE CLOUD COVER THAT COULD BE OFFSET BY
EVEN SLIGHT PERIODS OF SUN GIVEN THE HIGH 1000-850MB THICKNESSES.
GUIDANCE HIGHS ARE 90 TO 95 AND WILL PLAN TO GO BELOW THOSE ROUGHLY
A COUPLE OF DEGREES. OVERNIGHT LOWS THURSDAY NIGHT WITHIN A DEGREE
OR THREE OF 70.
FRIDAY THROUGH MONDAY...THE SLOW-MOVING SURFACE FRONT SHOULD BE
LOCATED OVER THE EASTERN CAROLINAS...GRADUALLY MOVING SOUTH WHILE
LIKELY WASHING OUT INTO THE EARLY PART OF THE WEEKEND. AS SURFACE
HIGH PRESSURE IS FORECAST TO NUDGE SOUTH BEHIND THE FRONT...COARSE
MODEL SOUNDINGS FROM BOTH THE GFS AND THE ECMWF SUGGEST
PRECIPITATION CHANCES MAY BE MORE LIMITED FRIDAY...RELATIVELY HIGHER
TOWARD INTERSTATE 95 CLOSER TO THE FRONT. CONTINUED WITH A SLIGHT
CHANCE FOR SHOWERS FRIDAY OVER THE WESTERN PIEDMONT WITH CHANCES
MAINLY ALONG AND EAST OF U.S. 1...ALTHOUGH IF THE MODEL SOUNDINGS
VERIFY THESE CHANCES MAY END UP BEING TOO HIGH. EVEN IF SHOWER
CHANCES ARE LESS BOTH THE GFS AND ECMWF PROVIDE FOR DECENT MEAN
MOISTURE AND PARTICULARLY UPPER-LEVEL MOISTURE LINGERING WHICH WOULD
MAKE THE DAY PARTLY SUNNY AT BEST.
OVER THE WEEKEND...THE SURFACE FRONT SHOULD DIMINISH JUST SOUTH OF
CENTRAL NORTH CAROLINA SATURDAY AS WEAK HIGH PRESSURE BUILDS IN.
UNDER RIDGING ALOFT SATURDAY...ANY SHOWERS SHOULD BE DIFFICULT TO
COME BY. WILL RETAIN A SLIGHT CHANCE OF A SHOWER TOWARD INTERSTATE
95 WHERE MOISTURE OVERALL SHOULD BE A LITTLE HIGHER AND SURFACE
PRESSURES A LITTLE LOWER...WITH LIFT POSSIBLY AIDED BY A SEA BREEZE.
HEIGHTS ALOFT START TO FALL SUNDAY INTO MONDAY AHEAD OF ANOTHER
SURFACE FRONT THAT SHOULD BE MOVING TOWARD CENTRAL NORTH CAROLINA
FROM THE NORTHWEST. COARSE ECMWF MODEL SOUNDINGS ARE FAIRLY CAPPED
SUNDAY WHILE GFS COARSE MODEL SOUNDINGS SHOW COOLER TEMPERATURES
ALOFT AND GREATER INSTABILITY...ENOUGH FOR AT LEAST ISOLATED/SLIGHT
CHANCES FOR SHOWERS SUNDAY WITH THE RELATIVELY HIGHER CHANCES THAT
DAY OVER THE WESTERN PIEDMONT WHERE ANY INSTABILITY SHOULD BE
GREATER.
BY MONDAY...TIMING DIFFERENCES WITH THE APPROACH OF THE SURFACE
FRONT ENSURE CONTINUATION OF CHANCES FOR SHOWERS AND STORMS THEN...
HIGHEST EARLIER MONDAY OVER THE WESTERN PIEDMONT THEN CHANCES
THROUGHOUT CENTRAL NORTH CAROLINA BY MONDAY AFTERNOON THROUGH MONDAY
NIGHT. BOTH THE ECMWF AND GFS COARSE MODEL SOUNDINGS SHOW SUFFICIENT
INSTABILITY AND LAYER LAPSE RATES FOR AT LEAST SCATTERED SHOWERS AND
THUNDERSTORMS ACROSS THE AREA BY MONDAY AFTERNOON. FOR HIGH
TEMPERATURES...LEANED TOWARD THE MEE MOS GUIDANCE WHICH SEEMED TO BE
A GOOD BLEND BETWEEN THE COOLER MEX MOS AND WARM 1000-850MB
THICKNESSES. HIGHS 85 TO 90 FRIDAY AND 87 TO 92 BY MONDAY. OVERNIGHT
LOWS MOSTLY 65 TO 70... ABOUT A CATEGORY COOLER SATURDAY NIGHT WHEN
IT WOULD SEEM THERE WOULD BE THE GREATER CHANCE OF A COMBINATION OF
SOMEWHAT DRIER LOW-LEVEL AIR AND AREAS OF CLEARING.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 235 AM TUESDAY......
THROUGH 06Z WED: RADAR SHOWS A SHIELD OF LIGHT RAIN BEGINNING TO
OVERSPREAD CENTRAL NC FROM W TO E...WITH CIGS AND VSBY LOWERING TO
MVFR CRITERIA ACROSS THE WESTERN PIEDMONT AND TRIAD REGIONS. SITES
FARTHER EAST WILL ALSO SEE FLT CONDITIONS GRADUALLY WORSEN BETWEEN
09Z-14Z. LOOK FOR MVFR FLT CONDITIONS TO PERSIST THROUGH 16-
18Z...THEN PRECIP IS EXPECTED TO COME MORE SCATTERED AND CONVECTIVE
IN NATURE THIS AFTERNOON AS BREAKS IN THE CLOUDS ALLOWS FOR SOME
SUNSHINE. SCATTERED SHOWERS/TSTMS THIS AFTERNOON AND EVENING WILL BE
CAPABLE OF BRIEFLY LOWERING FLT CONDITIONS TO IFR...ALONG WITH
LOCALIZED WIND GUSTS OF 20-30KTS.
AFTER 06Z WED: WITH LITTLE CHANGE IN THE PATTERN THROUGH THE REST OF
THE WEEK...LOOK FOR SCATTERED SHOWERS AND TSTMS WHICH WILL RESULT IN
LOCALIZED MVFR OR IFR CONDITIONS. VFR CONDITIONS OUTSIDE OF SHOWER
AND TSTM ACTIVITY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RAH
NEAR TERM...RAH
SHORT TERM...RAH
LONG TERM...DJF
AVIATION...RAH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1224 AM CDT TUE AUG 18 2015
.UPDATE...
ISSUED AT 1216 AM CDT TUE AUG 18 2015
QUICK UPDATE TO PRECIPITATION CHANCES AND TEMPERATURES. LATEST
MODEL GUIDANCE AND RADAR TRENDS INDICATE A SLOWER AND FURTHER
SOUTH PROGRESSION OF SHOWERS TONIGHT. TRIMMED POPS SOUTH AND
DELAYED THE EXPANSION EASTWARD BY A FEW HOURS. ALSO REMOVED THE
MENTION OF THUNDER NORTHER OF I-94. INSTABILITY IS NEARLY
NON-EXISTENT AND ONLY HEAVIER CONVECTIVE SHOWERS ALONG THE ND/SD
BORDER HAVE CONTAINED ANY LIGHTNING. SKIES WERE MOSTLY CLEAR NORTH
AND THIS WAS ALLOWING TEMPERATURES TO COOL FASTER THAN FORECAST.
THEREFORE...LOWERED TEMPERATURES A FEW DEGREES.
UPDATE ISSUED AT 947 PM CDT MON AUG 17 2015
SHOWERS WITH ISOLATED THUNDERSTORMS CONTINUE TO MOVE SLOWLY EAST
FROM THE SOUTHWEST PART OF THE STATE. THE MAIN QUESTION TONIGHT IS
HOW FAR NORTH TO GO WITH THE HIGHER POPS. THE LATEST 00Z NAM
SUGGESTS MOST OF THE RAIN WILL BE CONFINED TO THE ND / SD
BORDER...WHILE THE RAP AND HRRR STILL BRING IT NORTH OF I94. HAVE
INCREASED POPS IN THE SOUTH AND WEST TO CATEGORICAL...BUT TAPER
THEM RELATIVELY QUICKLY FARTHER NORTH.
UPDATE ISSUED AT 655 PM CDT MON AUG 17 2015
REGIONAL RADAR MOSAIC SHOWS SHOWERS AND ISOLATED THUNDERSTORMS
MOVING ACROSS SOUTHEAST MONTANA TOWARDS SOUTHWEST NORTH DAKOTA
AND NORTHWEST SOUTH DAKOTA. INSTABILITY ACROSS NORTH DAKOTA
REMAINS LIMITED...SO KEEPING THE MENTION OF THUNDERSTORMS AS
ISOLATED LOOKS REASONABLE. THE LATEST SHORT TERM MODELS STILL
FOCUS THE BEST RAIN CHANCES IN THE SOUTHWEST PART OF THE STATE
THIS EVENING...AND THE CURRENT FORECAST HAS THAT SCENARIO WELL
COVERED.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 342 PM CDT MON AUG 17 2015
CURRENT SURFACE ANALYSIS PLACES COOL HIGH PRESSURE OVER THE
NORTHERN PLAINS. UPPER LEVEL ANALYSIS PLACES BROAD TROUGH OVER THE
NORTH-CENTRAL CONUS WITH POTENT SHORT WAVE DIGGING OVER THE
NORTHERN ROCKIES INTO THE PLAINS. OVER OUR AREA...A FEW SHOWERS
CONTINUE OVER NORTH CENTRAL NORTH DAKOTA WITH A LITTLE JET STREAK
PASSING OVER...WHILE SHOWERS START TO WORK INTO THE WEST WITH THE
AFOREMENTIONED DIGGING SHORT WAVE.
FOR THE REMAINDER OF THIS AFTERNOON INTO TONIGHT...SHORT WAVE WILL
CONTINUE TO DIG TO THE SOUTHEAST WITH A BROAD AREA OF
PRECIPITATION DEVELOPING...PARTICULARLY OVER SOUTHEAST
MONTANA/EASTERN WYOMING INTO SOUTH DAKOTA. OUR AREA WILL BE ON THE
NORTHERN FRINGES WITH THE GREATEST PRECIPITATION CHANCES REMAINING
ALONG THE FAR SOUTHERN TIER OF THE STATE...DECREASING CHANCES
TOWARDS THE NORTH. INSTABILITY REMAINS LOW...THOUGH ENOUGH EXITS
FOR A FEW WEAKER THUNDERSTORMS TO DEVELOP.
ON TUESDAY...SYSTEM WILL CONTINUE ITS EASTERLY TRACK...CLOSING OFF
OVER EASTERN SOUTH DAKOTA. THIS WILL CONTINUE TO KEEP THE HIGHEST
CHANCES ALONG THE SOUTHERN TIER OF THE STATE. TEMPERATURES WILL BE
QUITE COOL FOR THIS TIME OF YEAR...WITH HIGHS SOUTH OF I-94
REMAINING IN THE 60S...WHILE AREAS TO THE NORTH MAY PUSH INTO THE
LOWER 70S.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 342 PM CDT MON AUG 17 2015
CHANCES FOR SHOWERS AND THUNDERSTORMS WILL LINGER INTO TUESDAY
NIGHT...AS A BROAD UPPER LEVEL TROUGH CONTINUES DIGGING EASTWARD
ACROSS THE NORTHERN PLAINS.
A SLOW WARMING TREND AND DRY WEATHER ARE EXPECTED WEDNESDAY INTO
EARLY FRIDAY...AS AN UPPER LEVEL SHORTWAVE RIDGE IS PROJECTED
EAST ACROSS THE AREA.
THE NEXT UPPER LEVEL TROUGH IS EXPECTED TO MOVE INTO THE NORTH
PLAINS BY LATE FRIDAY...BRINGING ANOTHER ROUND OF THUNDERSTORMS TO
THE STATE BY LATE FRIDAY INTO EARLY SUNDAY MORNING...HIGHLIGHTED
WELL WITHIN THE LONG RANGE MODELS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1216 AM CDT TUE AUG 18 2015
VFR CONDITIONS ARE EXPECTED AT ALL TAF SITES THROUGH THE TAF
PERIOD. RAIN IS LIKELY AT KDIK/KBIS THIS MORNING AND POSSIBLE AT
KJMS/KISN LATER IN THE DAY. BRIEF REDUCTIONS OF VIS AND CIGS ARE
POSSIBLE IN ANY HEAVIER SHOWERS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AJ
SHORT TERM...JJS
LONG TERM...AC
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
544 AM EDT TUE AUG 18 2015
.SYNOPSIS...
A WEAKENING UPPER AIR DISTURBANCE WILL SLIDE THROUGH THE AREA
TODAY. A STRONGER DISTURBANCE WILL MOVE INTO AND THROUGH THE
REGION LATER WEDNESDAY AND THURSDAY. DRIER CONDITIONS WILL RETURN
FOR THE END OF THE WEEK AND WEEKEND AS TEMPERATURES FALL BACK TO
NEAR NORMAL.
&&
.NEAR TERM /THROUGH TONIGHT/...
RADAR SHOWS AN MCS MOVING SLOWLY NORTH INTO FAR SWRN PA...WITH
THE EASTERN EXTENT OF THE RAIN EXTENDING FROM THE SOUTHERN LAURELS
DOWN INTO WEST VA. THIS IS ASSOCIATED WITH A SHEARING OUT
SHORTWAVE AND AN AREA OF WARM ADVECTION AND LOW LEVEL CONVERGENCE.
THE HRRR AND RAP CONFINE THE SHOWERS TO MY FAR WESTERN ZONES
THROUGH LATE MORNING BEFORE GENERATING MORE SPOTTY SCATTERED
SHOWERS AND STORMS FOR THE AFTERNOON.
WHAT`S LEFT OF THE WEAKENING SHORTWAVE WILL TRAVERSE THE REGION
TODAY WITH THE BEST CHANCE FOR RAIN BEING OVER THE WEST...AND
CHANCES DIMINISHING OVER CENTRAL AND EASTERN AREAS. WOULD NOT BE
SURPRISED IF THE LOWER SUSQ SEES MUCH OF ANY RAIN AT ALL.
IT WILL BE ANOTHER WARM-HUMID DAY...BUT THE CLOUDS AND SCATTERED
SHOWERS WILL LIKELY SHAVE A FEW DEG OFF YESTERDAYS READINGS.
TIMING THE SHORTWAVE IN THE MODEL GUIDANCE SUGGESTS WE WILL
EXPERIENCE A BIT OF A LULL IN THE SHOWERY CONDITIONS
OVERNIGHT...ESPECIALLY THE SECOND HALF OF THE OVERNIGHT. ANOTHER
MUGGY NIGHT IS IN STORE WITH LOWS GENERALLY IN THE MID 60S TO
LOWER 70S...SOME 10-15 DEF ABOVE NORMAL.
&&
.SHORT TERM /WEDNESDAY/...
AFTER A SHORT PERIOD OF WEAK RIDGING ALOFT TONIGHT IN THE WAKE OF
THE DEPARTING SHORTWAVE...WEDNESDAY WILL FEATURE HEIGHTS ALOFT
BEGINNING TO FALL ONCE AGAIN...ESPECIALLY THE LAST PART OF THE
DAY AS THE LARGE ANOMALOUSLY DEEP TROUGH OVER THE UPPER MIDWEST
BEGINS TO MOVE INTO THE WESTERN GR LAKES AND SOUTHERN CANADA. THE
CHANCES FOR SHOWERS WILL ONCE AGAIN BE ON THE RISE AS ANOTHER SHOT
OF DEEP MOISTURE ADVECTS INTO THE AREA ON A STRENGTHENING DEEP
SOUTHWESTERLY FLOW. THE GEFS SHOWS THE PWATS INCREASING TO 2-3 STD
DEV ABOVE NORMAL DURING THE DAY WED. THOUGH I PRETTY MUCH
BROADBRUSHED THE CHANCE FOR SCATTERED SHOWERS AND
STORMS...THINKING IS THE AFTERNOON WILL SEE THE BEST CHANCE OF
RAIN OVER MOST OF MY AREA.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
THERE IS PRETTY GOOD AGREEMENT THAT THE ANOMALOUSLY DEEP SYSTEM
TO OUR WEST WILL QUICKLY SHEAR OUT AND BRING THE MAIN SURGE OF
PRECIP/FORCING INTO THE LOCAL AREA THURSDAY.
I HAVE SOME CONCERN FOR LOCALIZED HEAVY RAINS DEVELOPING AS THE
SHORT RANGE MODELS SUGGEST THE FRONT WILL SLOW DOWN AS THE UPPER
JET SURGES INTO SOUTHERN CANADA. STRONG LOW LEVEL FRONTOGENETIC
FORCING IS INDICATED AS THE WAVY FRONT MOVES SLOWLY THROUGH
CENTRAL AND EASTERN AREAS. LATEST ENSEMBLES SHOW A SMALL PROB OF
1" OR MORE AMOUNTS OVER CENTRAL AND EASTERN AREAS THURSDAY
AFTERNOON AND EVENING...WITH THE ECMWF EVEN HINTING THAT AN AREA
OF HEAVY RAIN COULD LINGER INTO THURSDAY NIGHT OVER MOST OF MY
EASTERN ZONES.
GUIDANCE SUGGESTS THE FRONT IS BASICALLY EAST OF THE FORECAST AREA
BY FRIDAY...WITH PERHAPS FAR EASTERN AREAS STILL SEEING A
LINGERING SHOWER THREAT. BUT DRIER AIR MOVING IN BEHIND THE FRONT
LOOKS LIKE A HIGH CONFIDENCE FORECAST FOR FRIDAY AND
SATURDAY...BEFORE THINGS GET POTENTIALLY MUDDY ONCE AGAIN FOR THE
END OF THE WEEKEND.
WEAK TROUGHING ALOFT AND THE SURFACE HIGH SLIDING OFF THE NEW
ENGLAND COAST COULD CONSPIRE TO BRING THE CHANCES FOR SOME
SHOWERS...OR MAYBE EVEN LOW CLOUDS AND LIGHT RAIN OR DRIZZLE AS
DEPICTED IN THE OPERATIONAL GFS BACK INTO THE AREA FOR SUNDAY. I
KEPT THE CHANCES LOW...BUT HAVE LITTLE CONFIDENCE IN THE FORECAST
THAT FAR OUT.
IT WILL REMAIN WARM WITH DAILY HIGHS AVERAGING ABOVE NORMAL
THROUGHOUT THE PERIOD.
&&
.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
09Z TAFS SENT.
SOME MINOR ADJUSTMENTS MADE TO THE 09Z TAFS.
SOME SHOWERS AND THUNDERSTORMS TODAY...AS A WEAK SYSTEM LIFTS
NORTHWARD. FAR SE AREAS SUCH AS LNS...MAY SE LITTLE IF ANY RAIN
BEFORE LATE AFT.
MORE IN THE WAY OF SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE
ON WED INTO THU...AS A RATHER DEEP SYSTEM LIFTS NE TOWARD THE
LAKES.
HOWEVER...TREND WILL BE FOR SYSTEMS TO LIFT NW OF OUR AREA.
THIS WILL TREND TO TAPER THE AMT OF COLD AIR BEHIND THE
FRONTS AND ANY STORMS THAT FORM ALONG THE FRONT.
OUTLOOK...
WED...ISOLD PM TSRA IMPACTS POSS W MTNS.
THU...AM LOW CIGS/FOG POSS. SCT/NUMEROUS PM TSRA IMPACTS
POSSIBLE.
FRI-SAT...NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LA CORTE
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
513 AM EDT TUE AUG 18 2015
.SYNOPSIS...
A WEAKENING UPPER AIR DISTURBANCE WILL SLIDE THROUGH THE AREA
TODAY. A STRONGER DISTURBANCE WILL MOVE INTO AND THROUGH THE
REGION LATER WEDNESDAY AND THURSDAY. DRIER CONDITIONS WILL RETURN
FOR THE END OF THE WEEK AND WEEKEND AS TEMPERATURES FALL BACK TO
NEAR NORMAL.
&&
.NEAR TERM /THROUGH TONIGHT/...
RADAR SHOWS AN MCS MOVING SLOWLY NORTH INTO FAR SWRN PA...WITH
THE EASTERN EXTENT OF THE RAIN EXTENDING FROM THE SOUTHERN LAURELS
DOWN INTO WEST VA. THIS IS ASSOCIATED WITH A SHEARING OUT
SHORTWAVE AND AN AREA OF WARM ADVECTION AND LOW LEVEL CONVERGENCE.
THE HRRR AND RAP CONFINE THE SHOWERS TO MY FAR WESTERN ZONES
THROUGH LATE MORNING BEFORE GENERATING MORE SPOTTY SCATTERED
SHOWERS AND STORMS FOR THE AFTERNOON.
WHAT`S LEFT OF THE WEAKENING SHORTWAVE WILL TRAVERSE THE REGION
TODAY WITH THE BEST CHANCE FOR RAIN BEING OVER THE WEST...AND
CHANCES DIMINISHING OVER CENTRAL AND EASTERN AREAS. WOULD NOT BE
SURPRISED IF THE LOWER SUSQ SEES MUCH OF ANY RAIN AT ALL.
IT WILL BE ANOTHER WARM-HUMID DAY...BUT THE CLOUDS AND SCATTERED
SHOWERS WILL LIKELY SHAVE A FEW DEG OFF YESTERDAYS READINGS.
TIMING THE SHORTWAVE IN THE MODEL GUIDANCE SUGGESTS WE WILL
EXPERIENCE A BIT OF A LULL IN THE SHOWERY CONDITIONS
OVERNIGHT...ESPECIALLY THE SECOND HALF OF THE OVERNIGHT. ANOTHER
MUGGY NIGHT IS IN STORE WITH LOWS GENERALLY IN THE MID 60S TO
LOWER 70S...SOME 10-15 DEF ABOVE NORMAL.
&&
.SHORT TERM /WEDNESDAY/...
AFTER A SHORT PERIOD OF WEAK RIDGING ALOFT TONIGHT IN THE WAKE OF
THE DEPARTING SHORTWAVE...WEDNESDAY WILL FEATURE HEIGHTS ALOFT
BEGINNING TO FALL ONCE AGAIN...ESPECIALLY THE LAST PART OF THE
DAY AS THE LARGE ANOMALOUSLY DEEP TROUGH OVER THE UPPER MIDWEST
BEGINS TO MOVE INTO THE WESTERN GR LAKES AND SOUTHERN CANADA. THE
CHANCES FOR SHOWERS WILL ONCE AGAIN BE ON THE RISE AS ANOTHER SHOT
OF DEEP MOISTURE ADVECTS INTO THE AREA ON A STRENGTHENING DEEP
SOUTHWESTERLY FLOW. THE GEFS SHOWS THE PWATS INCREASING TO 2-3 STD
DEV ABOVE NORMAL DURING THE DAY WED. THOUGH I PRETTY MUCH
BROADBRUSHED THE CHANCE FOR SCATTERED SHOWERS AND
STORMS...THINKING IS THE AFTERNOON WILL SEE THE BEST CHANCE OF
RAIN OVER MOST OF MY AREA.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
THERE IS PRETTY GOOD AGREEMENT THAT THE ANOMALOUSLY DEEP SYSTEM
TO OUR WEST WILL QUICKLY SHEAR OUT AND BRING THE MAIN SURGE OF
PRECIP/FORCING INTO THE LOCAL AREA THURSDAY.
I HAVE SOME CONCERN FOR LOCALIZED HEAVY RAINS DEVELOPING AS THE
SHORT RANGE MODELS SUGGEST THE FRONT WILL SLOW DOWN AS THE UPPER
JET SURGES INTO SOUTHERN CANADA. STRONG LOW LEVEL FRONTOGENETIC
FORCING IS INDICATED AS THE WAVY FRONT MOVES SLOWLY THROUGH
CENTRAL AND EASTERN AREAS. LATEST ENSEMBLES SHOW A SMALL PROB OF
1" OR MORE AMOUNTS OVER CENTRAL AND EASTERN AREAS THURSDAY
AFTERNOON AND EVENING...WITH THE ECMWF EVEN HINTING THAT AN AREA
OF HEAVY RAIN COULD LINGER INTO THURSDAY NIGHT OVER MOST OF MY
EASTERN ZONES.
GUIDANCE SUGGESTS THE FRONT IS BASICALLY EAST OF THE FORECAST AREA
BY FRIDAY...WITH PERHAPS FAR EASTERN AREAS STILL SEEING A
LINGERING SHOWER THREAT. BUT DRIER AIR MOVING IN BEHIND THE FRONT
LOOKS LIKE A HIGH CONFIDENCE FORECAST FOR FRIDAY AND
SATURDAY...BEFORE THINGS GET POTENTIALLY MUDDY ONCE AGAIN FOR THE
END OF THE WEEKEND.
WEAK TROUGHING ALOFT AND THE SURFACE HIGH SLIDING OFF THE NEW
ENGLAND COAST COULD CONSPIRE TO BRING THE CHANCES FOR SOME
SHOWERS...OR MAYBE EVEN LOW CLOUDS AND LIGHT RAIN OR DRIZZLE AS
DEPICTED IN THE OPERATIONAL GFS BACK INTO THE AREA FOR SUNDAY. I
KEPT THE CHANCES LOW...BUT HAVE LITTLE CONFIDENCE IN THE FORECAST
THAT FAR OUT.
IT WILL REMAIN WARM WITH DAILY HIGHS AVERAGING ABOVE NORMAL THROUGHOUT
THE PERIOD.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
SOME SHOWERS TODAY...AS A WEAK SYSTEM LIFT NORTHWARD. FAR SE
AREAS SUCH AS LNS...MAY SE LITTLE IF ANY RAIN.
MORE IN THE WAY OF SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE
ON WED INTO THU...AS A RATHER DEEP SYSTEM LIFTS NE TOWARD THE
LAKES.
HOWEVER...TREND WILL BE FOR SYSTEMS TO LIFT NW OF OUR AREA.
THIS WILL TREND TO TAPER THE AMT OF COLD AIR BEHIND THE
FRONTS AND ANY STORMS THAT FORM ALONG THE FRONT.
PREVIOUS DISCUSSION BELOW.
A MCLEAR SKY AND NEARLY CALM WIND SHOULD PROMOTE PATCHY VALLEY
FOG TOWARDS DAWN ACROSS CENTRAL PA. CLIMATOLOGY SUGGESTS A PERIOD
OF IFR CONDS ARE POSSIBLE LATE TONIGHT AT KBFD/KIPT...BUT
INCREASING CLOUDS AT KBFD COULD LIMIT RAD COOLING AND FOG
POTENTIAL. ELSEWHERE...LATEST LAMP/NAM GUIDANCE...COMBINED WITH A
COMPARISON OF DWPT DEPRESSIONS FROM LAST EVENING...SUGGEST A BRIEF
MVFR VIS REDUCTION IS LIKELY ARND DAWN AT KUNV/KAOO/KLNS...SIMILAR
TO WHAT OCCURRED THIS AM.
A TROUGH OF LOW OF PRES LIFTING OUT OF THE OHIO VALLEY WILL SPREAD
SHOWERS AND POSS TSRA INTO THE AREA ON TUESDAY. ALTHOUGH VFR CONDS
WILL PREDOMINATE...BRIEF VIS REDUCTIONS ARE POSSIBLE IN ANY
SHOWERS OR TSRA. LATEST MDL TIMING SUGGEST THE SHOWERS WILL
OVERSPREAD THE W MTNS DURING LATE AM...AND REACH THE EASTERN HALF
OF PA DURING THE PM HOURS.
OUTLOOK...
WED...ISOLD PM TSRA IMPACTS POSS W MTNS.
THU...AM LOW CIGS/FOG POSS. SCT/NUMEROUS PM TSRA IMPACTS
POSSIBLE.
FRI-SAT...NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LA CORTE
AVIATION...FITZGERALD/MARTIN
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
402 AM CDT TUE AUG 18 2015
.SHORT TERM...
WATER VAPOR IMAGERY SHOWS A SHARP SHORTWAVE TROUGH CROSSING THE
ROCKIES AND EMERGING OVER THE CENTRAL AND NRN PLAINS THIS MORNING.
THIS IS PRODUCING SCATTERED CONVECTIVE ACTIVITY FROM
NEBRASKA...ARCING EAST INTO CENTRAL KS...THEN BACK SW ACROSS NW OKLA
AND ERN TX PANHANDLE...AND INTO ERN AND SRN NEW MEXICO. THIS
ACTIVITY IS MOSTLY SPLITTING OUR FORECAST AREA AT 3 AM...WITH THE
EASTERN BATCH JUST NICKING OUR NE COUNTIES AND THE WESTERN BATCH
STAYING WEST OF THE STATE LINE. HOWEVER...RADAR IS SHOWING A SLIGHT
UPTICK IN COVERAGE AND INTENSITY AT THIS TIME...AND THE HRRR AND RAP
SUGGEST THAT ISOLATED TO SCATTERED COVERAGE OF SHOWERS AND STORMS
WILL WORK THEIR WAY SEWD ACROSS MOST OF OUR FORECAST AREA THIS
MORNING. THE ACTIVITY WILL TEND TO WANE TOWARD SUNRISE...AND AT
THIS TIME IT LOOKS LIKE AN ISOLATED MENTION IN THE FORECAST AFTER
12 UTC WILL BE SUFFICIENT.
IT NOW APPEARS THAT MOST OF THE DAY WILL BE PRETTY QUIET AS MODEST
SUBSIDENCE REPLACES THE MODEST LIFT MOVING THROUGH THIS MORNING.
THIS SHOULD ALLOW TEMPS TO WARM A FEW DEGREES FROM YESTERDAY/S
READINGS WITH HIGHS EXPECTED TO TOP OUT IN THE LOWER 90S NORTHWEST
TO NEAR 100 IN THE SOUTHEAST. MEANWHILE...THE MUCH ANTICIPATED COLD
FRONT....CURRENTLY MOVING THROUGH ERN COLO AND WRN KS...WILL BE
MAKING IT/S WAY SOUTH THROUGH THE PANHANDLES. THE LATEST HIGH-RES
GUIDANCE IS IN GOOD AGREEMENT THAT AN INITIAL WIND SHIFT WILL WORK
INTO THE FAR SW TX PANHANDLE AND NW SPLNS BY EARLY AFTERNOON...BUT
THEN NOT MAKE MUCH ADDITIONAL PROGRESS THROUGH EARLY EVENING. THIS
WILL SET UP A SURFACE TROUGH RUNNING FROM THE WRN SOUTH PLAINS
INTO THE SRN TX PANHANDLE. DESPITE A NICE BUILDUP OF CAPE TO NEAR
3000 J/KG IN THIS AREA...THE CAP IS EXPECTED TO HOLD THROUGH MOST
OF THE AFTERNOON. LARGE-SCALE ASCENT SHOULD BEGIN TO INCREASE
EARLY THIS EVENING AS THE NEXT VORT MAX SWINGS ACROSS THE SRN
ROCKIES. ALTHOUGH THE BULK OF THIS LIFT WILL BE OFF TO OUR
NORTH...IT SHOULD TRIGGER SOME T-STORM DEVELOPMENT AS IT SPREADS
OVER THE FRONT AND SURFACE TROUGH. UNFORTUNATELY...MODEL GUIDANCE
REMAINS HIGHLY VARIABLE AND INCONSISTENT IN THE PLACEMENT AND
COVERAGE OF QPF AND MODEL REFLECTIVITY FIELDS...INCLUDING A FEW
SOLUTIONS...SUCH AS THE 00 UTC TTU-WRF...WHICH KEEPS THE FORECAST
AREA MOSTLY PRECIP FREE. AS SUCH...OUR CONFIDENCE REMAINS LOW
REGARDS THE EXTENT OF THUNDERSTORMS THIS EVENING AND THUS POPS ARE
ONLY IN THE 20 TO 40 PERCENT RANGE....MAXIMIZED ACROSS THE FAR SE
TX PANHANDLE. THE AVAILABLE INSTABILITY AND DEEP-LAYER SHEAR
SUPPORT THE IDEA OF SOME STORM ORGANIZATION AND A SEVERE WEATHER
THREAT...FOCUSED ON THE FAR SRN TX PANHANDLE AND NW
SPLNS...ALTHOUGH THE COVERAGE MAY BE JUST TOO LIMITED TO BE OF
SIGNIFICANT IMPACT.
THE COLD FRONT WILL SURGE THROUGH THE FORECAST AREA OVERNIGHT...WITH
BREEZY NE WINDS EXPECTED WITH THE FROPA EVEN OUTSIDE OF ANY T-STORM
ACTIVITY. LOW STRATUS WILL ALSO EXPAND IN COVERAGE BEHIND THE FRONT.
THE BEST RAIN CHANCES WILL GRADUALLY SHIFT EWD INTO THE ROLLING
PLAINS EARLY WEDNESDAY MORNING.
.LONG TERM...
MUCH COOLER AIR WILL BE ADVECTING INTO THE SOUTH PLAINS ON GUSTY
NORTHEASTERLY WINDS WEDNESDAY BEHIND THE EARLY DAY FROPA. SUSTAINED
WINDS NEAR 20 KNOTS COUPLED WITH HIGHS ONLY CLIMBING INTO THE 70S
FOR MOST SPOTS WILL MAKE FOR A FALL-LIKE FEEL IN THE AIR. IN
ADDITION...MOIST UPGLIDE ABOVE THE FRONTAL ZONE WILL YIELD A STRATUS
DECK WITH ENOUGH ELEVATED INSTABILITY PERHAPS SUPPORTING A RISK OF A
FEW SHOWERS/STORMS ACROSS THE EASTERN AND SOUTHEASTERN ZONES. OF
NOTE...THE RECORD MINIMUM HIGH FOR AUGUST 19TH IN LUBBOCK IS 74
DEGREES /SET IN 1956/ AND THIS COULD BE THREATENED IF CLOUDS HANG
TOUGH ALL DAY. SURFACE RIDGING WILL THEN SETTLE OVER THE REGION WITH
LIGHT WINDS AND THE COOLEST AIR SINCE LATE MAY. DEPENDING ON WHETHER
SKIES COMPLETELY CLEAR AND EXACTLY HOW LOW DEWPOINTS CAN DROP WITHIN
THE RIDGE...WE COULD ALSO THREATEN THE RECORD LOW THURSDAY MORNING
/THE CURRENT RECORD IS 54 DEGREES SET IN 1915/.
THE SURFACE RIDGE WILL SLIDE EASTWARD ON THURSDAY ALLOWING SOUTHERLY
WINDS TO GRADUALLY RETURN AND COUPLED WITH INCREASED INSOLATION
HIGHS WILL REBOUND BACK INTO THE 80S. WE WILL THEN SEE SLIM STORM
CHANCES CREEP BACK INTO THE FORECAST THURSDAY NIGHT INTO FRIDAY AS
ONE OR MORE SUBTLE DISTURBANCES MOVE THROUGH THE QUASI-ZONAL FLOW
AND GRAZE THE AREA FROM THE NORTH. THE SUPPRESSED SOUTHWESTERN UPPER
RIDGE IS THEN FORECAST TO EXPAND NORTHWARD AND BRIDGE TO AN UPPER
HIGH CENTERED OVER FLORIDA THIS WEEKEND WHILE AT THE SAME TIME A
SHARP TROUGH MOVES STEADILY ACROSS THE NORTHERN TIER OF THE NATION.
THE BUILDING HEIGHTS AND PROLONGED SOUTHERLY FLOW WILL ALLOW
TEMPERATURES TO MODERATE BACK UP TO NEAR AVERAGE BY FRIDAY AND
SATURDAY. EVEN WITH THE RIDGE BUILDING MORE SQUARELY OVERHEAD...A
SUBTROPICAL MOISTURE FETCH ALONG WITH CONVERGENCE ALONG A SURFACE
TROUGH WILL KEEP LOW THUNDER CHANCES GOING ACROSS THE WESTERN
ZONES ON SATURDAY. THE NORTHERN STREAM SYSTEM WILL THEN SEND A
COLD FRONT SOUTHWARD INTO THE SOUTHERN PLAINS ON SUNDAY BEFORE
STALLING OUT SOMEWHERE NEARBY AND THEN WASHING OUT EARLY NEXT
WEEK. THIS FRONT WILL PROVIDE AT LEAST A SLIM SHOT OF ADDITIONAL
CONVECTION ON SUNDAY...THOUGH WITHOUT ANY UPPER SUPPORT COVERAGE
WOULD LIKELY BE NO BETTER THAN SCATTERED.
AFTER ANOTHER BRIEF AND LESS DRAMATIC COOL DOWN /THAN ON
WEDNESDAY/ WITH THE FRONT LATE THIS WEEKEND...HOTTER AND DRY
WEATHER SHOULD FOLLOW. THIS WILL OCCUR AS UPPER RIDGING IS
PROGGED TO AMPLIFY OVER THE SOUTHERN ROCKIES INTO THE SOUTHERN
HIGH PLAINS DURING THE EARLY AND MIDDLE PARTS OF NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 92 58 75 53 / 20 30 10 0
TULIA 91 60 74 54 / 20 40 20 0
PLAINVIEW 92 61 74 53 / 20 30 20 0
LEVELLAND 93 63 77 56 / 20 30 20 0
LUBBOCK 94 65 77 57 / 20 30 20 10
DENVER CITY 96 65 79 56 / 20 20 20 10
BROWNFIELD 94 65 79 56 / 20 30 20 10
CHILDRESS 96 67 78 58 / 20 40 30 10
SPUR 95 67 78 58 / 20 30 30 20
ASPERMONT 99 70 83 61 / 20 30 30 30
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
33/23
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1242 AM CDT TUE AUG 18 2015
.AVIATION...
ISOLD SHRA/TSRA ARE POSSIBLE ALONG THE SEABREEZE WELL SOUTHEAST
OF I-35 TUESDAY AFTERNOON WITH NO IMPACT TO TAF SITES. VFR SKIES
START THE FORECAST. STRATUS WITH IFR/MVFR CIGS WILL DEVELOP
OVERNIGHT..18/07Z-10Z..ALONG THE ESCARPMENT INTO THE HILL COUNTRY
AND THEN SPREAD TO THE MOST OF THE REMAINDER OF SOUTH CENTRAL
TEXAS BY MORNING. CLOUDS LIFT AND BECOME FEW-SCT VFR CUMULUS LATE
MORNING THROUGH EVENING. STRATUS WITH IFR/MVFR CIGS REDEVELOPS
TUESDAY NIGHT AFTER 19/06Z. S TO SE WINDS LESS THAN 10 KTS
INCREASE TO 10 TO 15 KTS ON TUESDAY...BACK WITH PASSAGE OF THE
SEABREEZE MID AFTERNOON INTO EVENING...AND THEN DECREASE TUESDAY
NIGHT.
&&
.PREV DISCUSSION... /ISSUED 830 PM CDT MON AUG 17 2015/
UPDATE...
CONVECTION HAS ENDED ACROSS THE AREA WITH THE LOSS OF DIURNAL
HEATING. AN UPDATE TO THE TEXT...GRAPHIC...AND GRID FORECAST WAS
JUST SENT TO RE-TREND VARIABLES THROUGH 12Z TUESDAY...BUT NO MAJOR
CHANGES TO THE PREVIOUS FORECAST.
PREV DISCUSSION... /ISSUED 643 PM CDT MON AUG 17 2015/
UPDATE...00Z AVIATION UPDATE BELOW.
AVIATION...VFR CONDITIONS CONTINUE THROUGH THE EVENING HOURS.
ISOLATED SHRAS WILL END AROUND SUNSET. PATCHES OF MVFR MORNING
STRATUS WERE EVIDENT THIS MORNING...AND COVERAGE SHOULD BE
SLIGHTLY GREATER OVERNIGHT AND TUESDAY MORNING. NAM BUFR SOUNDINGS
COMBINED WITH 950MB MOISTURE PROGS FROM VARIOUS MODELS INDICATE
STRATUS DEVELOPMENT ALONG THE SOUTHERN EDGE OF THE ESCARPMENT
NEAR SAT AROUND 08Z...POSSIBLY SPREADING INTO AUS TERMINAL 09Z-12Z
AS LOW LEVEL FLOW VEERS SLIGHTLY MORE SW. THERE IS A CHANCE THAT
DRT COULD SEE A PERIOD OF MVFR CEILINGS 13Z-16Z PER NAM BUFR
SOUNDINGS AND HRRR SOLUTIONS...ALTHOUGH CONFIDENCE IS LOWER THAN
I-35 SITES. STRATUS WILL SCATTER OUT QUICKLY LATE MORNING WITH VFR
CONDITIONS AGAIN TUE AFTERNOON. ISOLATED SHRAS AGAIN POSSIBLE TUE
DURING THE MID AFTERNOON AND EVENING HOURS EAST OF I-35. THESE ARE
NOT EXPECTED TO IMPACT THE I-35 TAF SITES. S AND SE FLOW LATE TUE
MORNING AND AFTERNOON WILL BE SLIGHTLY STRONGER...WITH SOME GUSTS
NEAR 20 KTS POSSIBLE.
PREV DISCUSSION... /ISSUED 255 PM CDT MON AUG 17 2015/
SHORT TERM (TONIGHT THROUGH TUESDAY)...
NO MAJOR HIGHLIGHTS THROUGH TUESDAY WITH NEAR NORMAL CONDITIONS
AND LOW END RAIN CHANCES FOR THE COASTAL PLAINS.
WATER VAPOR AND RUC ANALYSIS REVEAL A SHEAR AXIS AND MID TO UPPER
LEVEL LOW ACROSS THE MID MISSISSIPPI VALLEY EXTENDING SOUTHWEST
ALONG THE TEXAS COAST. THIS FEATURE ALONG WITH AFTERNOON
INSTABILITY WILL GOVERN THE WEATHER PATTERN THROUGH
TUESDAY BY KEEPING TEMPERATURES NEAR NORMAL AND ONLY 20-30%
TSTORM CHANCES ALONG THE COAST WHERE THE SEA-BREEZE CONVERGENCE
WILL BE MORE ACTIVE. PRECIPITABLE WATER AMOUNTS CURRENTLY RANGE
FROM 1.0" TO 1.6" FROM THE RIO GRANDE VALLEY TOWARDS THE COASTAL
PLAINS. THESE VALUES ARE ABOUT 0.5 TO 1 STANDARD DEVIATION BELOW
NORMAL AND THUS RESULTING IN LIMITED SHOWER/STORM ACTIVITY ACROSS
A MAJORITY OF THE REGION. THIS PATTERN WILL CONTINUE THROUGH
TOMORROW WITH ONLY LIMITED SHOWERS AND A FEW THUNDERSTORMS ALONG
THE COASTAL PLAINS.
LONG TERM (WEDNESDAY THROUGH MONDAY)...
THE LOW-LEVEL PATTERN WILL CHANGE UP MID TO LATE WEEK AS A
BOUNDARY APPROACHES THE REGION FROM THE NORTH WITH HIGHER RAIN
CHANCES AND LOWER MAX HIGH TEMPERATURES LIKELY.
BY MID-WEEK...GLOBAL MODELS AGREE THAT A LARGE LONG WAVE TROUGH
WILL DEVELOP OVER THE CENTRAL CONUS AND WITH ADDITIONAL SHORTWAVE
TROUGH SUPPORT OVER NEW MEXICO AND TEXAS...A PSEUDO COLD FRONT
WILL APPROACH THE REGION FROM THE NORTH LATE WEDNESDAY INTO
THURSDAY MORNING. WEDNESDAY WILL REMAIN NEAR NORMAL TEMPERATURE
WISE WITH HIGHS STILL IN THE MID TO UPPER 90S AREA WIDE AND LOWER
RAIN CHANCES OF 20-40% AREA WIDE. RAIN CHANCES WILL INCREASE GOING
THROUGH THE OVERNIGHT INTO THURSDAY MORNING FOR THE HILL COUNTRY
AS THE BOUNDARY APPROACHES BUT THEN LOOKS TO STALL. WITH THE
SHEAR AXIS OVER TOP OF THE FRONT...THIS SET-UP SHOULD PROVIDE
AREAS WITH MORE CLOUDS AND WITH PWATS INCREASING TO 1.4" TO
1.8"...MORE WIDESPREAD RAIN CHANCES OF AT LEAST 50% APPEAR A
NOMINAL ROUTE TO GO FOR THURSDAY AND CONTINUING INTO FRIDAY. 12Z
GFS APPEARS TO HAVE A MESOSCALE FEEDBACK ISSUE BY PRODUCING A QPF
BULLSEYE JUST SOUTH OF THE REGION AS IT CONSOLIDATES THE UPPER LOW
INTO A TIGHTER CLOSED LOW. SINCE THIS IS THE FIRST ADVERTISEMENT
OF THIS EVOLUTION...WILL SIDE MORE WITH CONSISTENCY AND THE EC
WHICH ALSO LINGERS THE MID LEVEL ENERGY OVER THE REGION. THE EXTRA
CLOUDS SHOULD RESULT IN MAX HIGHS BEING REDUCED TO LOW TO MID 90S
BEING QUITE PLAUSIBLE.
OVER THE WEEKEND...RAIN CHANCES LOOK TO DECREASE AS THE FRONT
WASHES OUT AND SHIFTS NORTH WITH A SUBTROPICAL RIDGE SLOWLY
INCREASING ITS INFLUENCE ACROSS THE NORTH GULF.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 77 98 76 94 76 / 10 20 50 40 20
AUSTIN BERGSTROM INTL AIRPORT 74 97 74 94 74 / 10 20 50 50 20
NEW BRAUNFELS MUNI AIRPORT 76 99 76 93 75 / 10 20 40 50 30
BURNET MUNI AIRPORT 75 96 74 92 74 / - 20 50 30 10
DEL RIO INTL AIRPORT 77 100 78 95 75 / - 20 30 40 20
GEORGETOWN MUNI AIRPORT 77 98 75 93 75 / 10 20 50 40 20
HONDO MUNI AIRPORT 74 98 76 94 74 / - 20 30 50 20
SAN MARCOS MUNI AIRPORT 77 97 76 93 75 / 10 20 40 50 20
LA GRANGE - FAYETTE REGIONAL 78 98 76 93 76 / 20 30 40 50 30
SAN ANTONIO INTL AIRPORT 78 97 78 94 77 / - 20 40 50 30
STINSON MUNI AIRPORT 77 99 78 95 76 / 10 20 30 50 30
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...04
SYNOPTIC/GRIDS...HAMPSHIRE
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
142 AM EDT TUE AUG 18 2015
.SYNOPSIS...
WEAK HIGH PRESSURE ACROSS THE REGION TONIGHT WILL WEAKEN AND
SLIDE EAST TO OFFSHORE THE MID ATLANTIC COAST ON TUESDAY. A COLD
FRONT IS EXPECTED TO DRIFT SOUTHEAST TOWARD THE REGION WEDNESDAY
INTO THURSDAY BEFORE CROSSING INTO THE AREA THURSDAY NIGHT. THIS
WILL RESULT IN MULTIPLE PERIODS OF SHOWERS AND STORMS THROUGH
THURSDAY BEFORE DRIER AIR WORKS IN BEHIND THE PASSING FRONT ON
FRIDAY.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 825 PM EDT MONDAY...
EVENING SOUNDINGS SHOW QUITE A BIT OF MOISTURE AND INSTABILITY
HAVING MADE A RETURN TO THE REGION TONIGHT WITH DEEPER SOUTHERLY
FLOW AND PWATS NEAR 1.5 INCHES. HOWEVER FAINT CAP ALOFT ALONG WITH
MOST LIFT BEING WEST OF THE MOUNTAINS WITH THE UPSTREAM
IMPULSE...HAS KEPT MOST ORGANIZED CONVECTION CONFINED TO THE FAR
WEST ON THE LEADING EDGE OF THE PCPN SHIELD AND WITH RESIDUAL
OUTFLOW. LATEST ANALYSIS SHOWING A DECENT AMOUNT OF LEFTOVER
INSTABILITY SPCLY BLUE RIDGE EAST SO TRICKY IN REGARDS TO WHETHER
OR NOT COVERAGE WILL FILL IN OVER THE NEXT FEW HOURS DESPITE LOSS
OF HEATING. LATEST HRRR REMAINS QUITE WET IN DEVELOPING SHRA/TSRA
ACROSS MUCH OF THE WEST OUT TO THE BLUE RIDGE BY MIDNIGHT WITH
SOME OF THIS COVERAGE HEADING EAST INTO THE PIEDMONT BEFORE
DAYBREAK. THIS LOOKS A BIT OVERDONE BUT GIVEN COVERAGE DEVELOPING
ACROSS THE SW AND LESS WORKED OVER NATURE TO THINGS FROM THIS
AFTERNOON WILL SPEED UP LIKELY POPS WEST AND EDGE HIGHER CHANCES
EAST OVERNIGHT. TEMPS TO REMAIN MUCH MORE ON THE WARM/MUGGY SIDE
OVERNIGHT GIVEN THE INCREASE IN MOISTURE...AND EXPECT SOME EASTERN
LOCATIONS TO STAY ABOVE 70 SO BUMPING UP LOWS A FEW DEGREES
OVERALL.
PREVIOUS DISCUSSION AS OF 235 PM EDT MONDAY...
STICKING CLOSER TO THE LOCAL WRF/HRRR THIS AFTERNOON INTO THE
EVENING WITH SCATTERED SHOWER AND STORM COVERAGE FROM THE BLUE
RIDGE WEST. COVERAGE AT THE MOMENT IS WIDELY SCATTERED WITH BEST
INSTABILITY SITUATED OVER THE NC/VA FOOTHILLS...WHERE SOME CELLS
HAD DEVELOPED INTO THUNDERSTORMS. MEAN FLOW WILL STAY WEAK SO
HEAVY RAINERS WILL OCCUR.
THIS ACTIVITY DIMINISHES SOMEWHAT THIS EVENING WITH LOSS OF
HEATING...BUT OVERNIGHT THE SHORTWAVE FROM SOUTHERN ILLINOIS TO MID
TENNESSEE WILL WORK NORTHEAST ACROSS THE MOUNTAINS INCREASING LIFT
AND WITH HIGHER PWATS...SHOULD SEE AN AREA OF SHOWERS...MAYBE A
RUMBLE OF THUNDER TRACK INTO THE MOUNTAINS. HAVE LIKELY TO SOME
CATEGORICAL POPS MAINLY WEST OF A COVINGTON VA TO MOUNT AIRY NC
LINE...WITH QUICKLY DIMINISHING POPS TO SLIGHT CHANCE EAST OF
LYNCHBURG/DANVILLE UNDERNEATH THE SFC HIGH.
THE FLOW WILL INCREASE AT 8H SO SHOWERS SHOULD BE MOVING A LITTLE
FASTER THAN THIS AFTERNOON. WITH PLENTY OF CLOUDS LOW TEMPS WILL BE
ELEVATED IN THE MID 60S TO AROUND 70.
TUESDAY...SHORTWAVE LIFTS NORTHEAST...BUT THERE IS SOME WEAK
UPPER SUPPORT AND DIFFLUENCE REMAINING TO KEEP LIKELY POPS GOING
ACROSS MOST OF THE FORECAST AREA. STORM CHANCE WILL BE LIMITED BY
CLOUD COVER BUT THINK THE UPPER SUPPORT IS ENOUGH TO HAVE THUNDER
INTO THE REGION BY AFTERNOON. HIGHS WILL BE TEMPERED BY CLOUD
COVER BUT WILL BE HUMID. TEMPS WILL RUN FROM THE LOWER TO MID 70S
OVER THE HIGHER ELEVATIONS AND ADJACENT VALLEYS IN THE WEST...WITH
UPPER 70S TO LOWER 80S ACROSS THE FOOTHILLS AND PIEDMONT INCLUDING
THE ROANOKE VALLEY.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
AS OF 230 PM EDT MONDAY...
THE CWA WILL BE EXPOSED TO SOUTHERLY FLOW FROM THE COMBINATION OF
HIGH PRESSURE OFFSHORE...AND AN APPROACHING COLD FRONT IN THE PLAINS
DURING TUESDAY NIGHT INTO WEDNESDAY. SOME CONVECTIVE ACTIVITY MAY
NOT FADE OUT SO QUICKLY IN THE NIGHTTIME HOURS DUE TO INCREASING
INSTABILITY AND MOISTURE AHEAD OF THE FRONT. AS A RESULT...MOST OF
THIS FORECAST PERIOD WILL BE EMBEDDED IN CHANCES OF SHOWERS AND
THUNDERSTORMS...WITH SOME DIURNAL VARIATION IN THE THUNDERSTORM
COVERAGE. DURING WEDNESDAY AFTERNOON AND EVENING...POPS WERE KEPT
HIGHEST MAINLY WEST OF THE BLUE RIDGE.
AS THE COLD FRONT DRAWS NEARER ON THURSDAY...LOOK FOR COVERAGE AND
ACTIVITY OF THE SHOWERS AND THUNDERSTORMS TO INCREASE MORE
SIGNIFICANTLY...ESPECIALLY WEST OF THE BLUE RIDGE. BOTH THE 12Z
ECMWF AND GFS MODELS SHOW THE EXPECTED FRONTAL PASSAGE AROUND
THURSDAY EVENING. ALTHOUGH SEVERE WEATHER THREAT PROJECTIONS APPEAR
LOW FROM SPC...THERE WILL BE A THREAT OF HEAVY RAIN HITTING THE SAME
LOCATIONS REPEATEDLY ON WEDNESDAY AND THURSDAY...WHICH COULD INDUCE
LOCALIZED FLOODING. AFTER THE FRONT CLEARS THE CWA BY EARLY FRIDAY
MORNING...CLOUD COVER AND POPS WILL GRADUALLY LESSEN.
TEMPERATURES DO NOT SHOW MUCH APPRECIABLE CHANGE BEFORE THE COLD
FRONT ARRIVES. THE AIR MASS WILL BECOME INCREASINGLY HUMID ON
WEDNESDAY AND THURSDAY...WHERE LOW TEMPERATURES MAY FAIL TO DROP
BELOW THE MID 60S IN THE MOUNTAINS...AND THE UPPER 60S TO THE LOWER
70S IN THE PIEDMONT. HIGHS SHOULD VARY FROM THE UPPER 70S TO THE
UPPER 80S...WHICH IS WELL IN AGREEMENT WITH THE MOS GUIDANCE. LOWS
ON FRIDAY MORNING WILL BE A LITTLE COOLER THANKS TO THE FRONTAL
PASSAGE...AS TEMPERATURES MAY HIT 60 DEGREES OR LOWER IN THE HIGHER
ELEVATIONS.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 218 PM EDT MONDAY...
LOW CONFIDENCE FORECAST DURING THE PERIOD AS MODELS ARE AGGRESSIVELY
PUSHING A COLD FRONT SOUTH INTO THE CAROLINAS ON FRIDAY. THERE ARE
SEVERAL REASONS REGARDING OUR LOW CONFIDENCE. ONE BIG FACTOR IS THE
TIME OF YEAR. MODELS TEND TO PUSH FRONTS TOO FAR SOUTH DURING
AUG-OCT TIME FRAME. ANOTHER DEALS WITH A WEAK SURFACE HIGH
PRESSURE BEHIND THE FRONT AND A STRONG UPPER LEVEL RIDGE ACROSS
THE GULF STATES. THE SURFACE FRONT COULD PUSH SOUTH INTO CENTRAL
NORTH CAROLINA...HOWEVER MID AND UPPER LEVEL MOISTURE WILL KEEP
CLOUDS AND THE CHANCE FOR RAIN IN THE AREA ONGOING INTO THE
WEEKEND. SINCE THIS IS A WEAK SURFACE HIGH/WEDGE...BOUNDARY LIKELY
TO RETREAT NORTH...KEEPING THE CHANCES FOR SHOWERS IN THE AREA
THROUGH THE WEEKEND. THE THREAT FOR SHOWERS AND THUNDERSTORMS
INCREASES MONDAY AS A STRONG COLD FRONT APPROACHES FROM THE WEST.
ALONG WITH THE LOW CONFIDENCE FORECAST...WE WILL KEEP TEMPERATURES
CLOSE TO SEASONAL LEVELS THROUGH THE PERIOD. THE COOLEST OF MAY BE
SATURDAY AND THE WARMEST MONDAY.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 140 AM EDT TUESDAY...
AS OF 140 AM EDT...AREAS OF RAIN WITH EMBEDDED HEAVIER SHOWERS
AND ISOLATED THUNDERSTORMS HAVE LIFTED NORTH AND EAST AND HAVE
OVERSPREAD MOST OF THE MOUNTAINS AND FOOTHILLS. THIS AREA
ASSOCIATED WITH INCREASING MOISTURE ADVECTION AND FORCING WITH
APPROACH OF WEAK UPSTREAM SHORT WAVE TROF. SHOWERS LIKELY TO
CONTINUE TO IMPACT OR MOVE INTO ALL TERMINAL FORECAST SITES
OVERNIGHT.
AS LOWER TROPOSPHERE GRADUALLY SATURATES...EXPECT TO SEE GRADUAL
REDUCTION OF CEILINGS AND VISIBILITIES IN MOST MOUNTAIN LOCATIONS
INTO MVFR RANGE...PERHAPS INTO IFR RANGE ALONG/NEAR HIGHER MOUNTAIN
RIDGES AND ACROSS THE IMMEDIATE EAST FLANKS OF THE BLUE RIDGE.
OUT ACROSS THE PIEDMONT...MOST NOTABLY AT KLYH AND KDAN...DIP INTO
MVFR RANGE POSSIBLE LATER TONIGHT...BUT PROBABILITY OF SUCH AN
OCCURRENCE NOT AS HIGH AS POINTS FURTHER WEST.
PERIODIC ROUNDS OF SHOWERS WITH ISOLATED ELEVATED THUNDER LIKELY
TO CONTINUE ON TUESDAY AS RIPPLES OF ENERGY CONTINUE TO TRAVERSE
THE REGION WITHIN AN AXIS OF TROPICAL MOISTURE. CONTINUED THREAT
OF PRECIPITATION AND GOOD LOW LEVEL MOISTURE ON WEAK UPSLOPING
WINDS MAY DELAY GRADUAL IMPROVEMENT BACK TO VFR CONDITIONS AT MOST
TERMINAL FORECAST UNTIL LATE MORNING/EARLY AFTERNOON...WITH
IMMEDIATE EAST FLANKS OF THE APPALACHIANS/BLUE RIDGE PERHAPS NOT
MIXING UP/BACK TO VFR UNTIL MID-LATE AFTERNOON DUE TO PERSISTENT
WEAK UPSLOPING WIND. HOWEVER...PLENTY OF CLOUDS IN 3000-5000 RANGE
SHOULD OFFSET EXTENT OF DAYTIME HEATING SUCH THAT MOST INSTABILITY
REMAINS PROGGED TO THE SOUTH AND WEST...SO NOT INCLUDING ANY
MENTION OF THUNDER THREAT AT ANY TERMINAL FORECAST POINT AT THE
PRESENT TIME.
EXPECT SHOWERS TO TAPER OFF TUESDAY NIGHT AS UPPER SUPPORT EXITS
AND THE REGION MOVES INTO A LULL BETWEEN THE PASSING IMPULSES AND
THE UPSTREAM COLD FRONT. LINGERING MOISTURE SHOULD MAKE FOR
WIDESPREAD SUB-VFR IN THE WAKE OF THE SHOWERS WITH LOTS OF STRATUS
AND FOG AROUND UNTIL LATE TUESDAY NIGHT.
EXTENDED AVIATION DISCUSSION...
WEDNESDAY THROUGH THURSDAY....SHOWERS AND THUNDERSTORMS...
INCLUDING SUB-VFR CONDITIONS...WILL BE MORE SCATTERED TO NUMEROUS
THANKS TO A SLOW MOVING FRONTAL BOUNDARY THAT WILL STALL JUST
NORTHWEST OF THE REGION. THIS BOUNDARY WILL ACT AS THE FOCUSING
MECHANISM FOR MULTIPLE ROUNDS OF SHOWERS AND THUNDERSTORMS
ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS FOLLOWED BY
PATCHY FOG DURING THE OVERNIGHTS.
WE WILL START TO DRY OUT SOME GOING INTO FRIDAY AS THE FRONT MOVES
SOUTHEAST...BUT SOME LINGERING ACTIVITY POSSIBLE OVER THE KDAN TO
KTNB CORRIDOR. SHOULD RETURN TO OVERALL VFR SATURDAY WITH THE
FRONT OFFSHORE AND WEAK HIGH PRESSURE ABOUT OVERHEAD FOR MUCH OF
THE DAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...JH/WP
SHORT TERM...PW
LONG TERM...RCS
AVIATION...AMS/JH/WERT/WP
FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE
.SHORT TERM...TODAY...TONIGHT...AND WEDNESDAY
ISSUED AT 316 AM CDT TUE AUG 18 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A COLD
FRONT STRETCHING ACROSS SOUTHWEST TO EAST-CENTRAL WISCONSIN EARLY
THIS MORNING. A SECONDARY FRONT RUNS ACROSS SOUTHERN MINNESOTA TO
EASTERN LAKE SUPERIOR. WEAK FGEN COMBINED WITH LINGERING ELEVATED
INSTABILITY CONTINUE TO GENERATE SCATTERED SHOWERS ALONG BOTH
FRONTS. BETTER MOISTURE AND INSTABILITY RESIDES OVER IOWA AND THE
PLAINS WHERE THUNDERSTORMS ARE OCCURRING. LOOKING FURTHER
UPSTREAM...LOW PRESSURE IS DEVELOPING OVER NORTHEAST COLORADO AHEAD
OF A DIGGING SHORTWAVE TROUGH. PRECIP TRENDS ALONG THE FRONT AND
ASSOCIATED WITH THE SURFACE LOW ARE THE MAIN FORECAST CONCERNS.
MODELS HAVE SLOWED DOWN THE PROGRESSION OF SURFACE FEATURES
SOMEWHAT. THE GFS IS A CLEAR OUTLIER...PROBABLY DUE TO ITS RATHER
POOR INITIALIZATION. PREFER A BLEND OF THE NAM/ECMWF/GEM.
TODAY...AS LOW PRESSURE CONSOLIDATES OVER THE CENTRAL PLAINS...THE
PRIMARY COLD FRONT IS PROJECTED TO STALL OVER CENTRAL AND EAST-
CENTRAL WISCONSIN...NEAR OR JUST SOUTH OF THE SOUTHERN FORECAST AREA
BORDER. WILL PROBABLY SEE AN UPTICK OF SHOWER ACTIVITY THIS MORNING
WITH WEAK SHORTWAVES MOVING OVERHEAD. ONCE THESE SHORTWAVES PASS TO
THE EAST BY LATE MORNING...NORTHERN WISCONSIN MAY SEE A DRY PERIOD
SO REDUCED PRECIP CHANCES THERE. SCATTERED SHOWERS WILL STILL IMPACT
THE SOUTH...CLOSER TO THE STALLED FRONT. WILL LIKELY SEE SHOWERS AND
A FEW STORMS BECOME MORE WIDESPREAD OVER CENTRAL WISCONSIN LATE IN
THE AFTERNOON AS MID-LEVEL FLOW STRENGTHENS OVER THE BOUNDARY.
HIGHS RANGING FROM THE MID 60S NORTH TO MID 70S SOUTH.
TONIGHT...A STRONG AREA OF LOW PRESSURE WILL LIFT NORTHEAST TOWARDS
MINNEAPOLIS WHILE PUSHING A COLD FRONT INTO SOUTHWEST OR CENTRAL
WISCONSIN BY 12Z WED. AS LARGE-SCALE ASCENT INCREASES...SHOULD SEE
AREAS OF SHOWERS AND THUNDERSTORMS LIFT NORTHEAST ACROSS THE
FORECAST AREA. THE MOST POTENT SWATH OF STORMS SHOULD ARRIVE LATE
IN THE NIGHT AHEAD OF THE COLD FRONT AND CLOSED MID-LEVEL
CIRCULATION. THOUGH INSTABILITY WILL BE QUITE LOW...PWATS WILL BE
GREATER THAN 1.5 INCHES AND FORCING WILL BE EXCELLENT. WIND FIELDS
ALOFT WILL ALSO BE STRENGTHENING AS 850MB WINDS APPROACH 40-45 KTS.
THOUGH CONVECTION WILL LIKELY BE LOW TOPPED...ANY CONVECTION WILL BE
CAPABLE OF BRINGING DOWN THESE STRONGER WINDS. THEREFORE...A
MARGINAL RISK LOOKS REASONABLE FOR THE SOUTHWEST FORECAST AREA.
TEMPS WILL NOT FALL MUCH TONIGHT. LOWS AROUND 60 NORTH TO THE MID
60S SOUTH.
WEDNESDAY...LOW PRESSURE WILL SLOWLY MOVE NORTHEAST OVER FAR
NORTHWEST WISCONSIN AS THE COLD FRONT SWEEPS ACROSS NORTH-CENTRAL
AND NORTHEAST WISCONSIN. SHOWERS AND STORMS ARE A DECENT BET AHEAD
OF THE FRONT DURING THE MORNING...AND THE THREAT OF STRONG GUSTY
WINDS WILL ACCOMPANY ANY STORMS. THE FRONT WILL EXIT NORTHEAST
WISCONSIN BY MID TO LATE AFTERNOON ENDING ANY STORM THREAT. WRAP
AROUND LIGHT SHOWERS MAY SPREAD INTO NORTH-CENTRAL WISCONSIN BY
EARLY EVENING. HIGHS RANGING FROM THE MID 60S WEST TO MID 70S EAST.
.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY
ISSUED AT 316 AM CDT TUE AUG 18 2015
THE STRONG COLD FRONT AND UPPER LEVEL CYCLONE...THAT WILL IMPACT
THE AREA IN THE SHORT TERM...WILL DEPART THE REGION ON THEIR WAY
TOWARD HUDSON BAY DURING THE LATTER HALF OF THE WEEK. THE CHANCE
FOR RAIN WILL DECREASE AS THESE FEATURES DEPART...ENDING BY 00Z
FRIDAY. UPPER FLOW ACROSS THE REGION BRIEFLY BECOMES ZONAL...THEN
SOUTHWEST AS A WEST COAST TROUGH TRAVERSES THE CONUS. ANOTHER
COLD FRONT IS FORECAST TO MOVE ACROSS THE REGION OVER THE WEEKEND
ALONG WITH THE TROUGH. THIS WILL BRING CHANCES FOR THUNDERSTORMS
BACK TO THE AREA FROM SATURDAY NIGHT THROUGH SUNDAY NIGHT.
COLDER THAN NORMAL TEMPERATURES CAN BE EXPECTED THURSDAY BEFORE
FLOW ALOFT FLATTENS AND WARMER THAN NORMAL CONDITIONS RETURN FOR
FRIDAY AND SATURDAY. CLOUDS AND RAIN WILL KEEP HIGHS CLOSER TO
NORMAL ON SUNDAY. EXPECT COLDER THAN NORMAL TEMPERATURES ON MONDAY
BEHIND THE COLD FRONT.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1037 PM CDT MON AUG 17 2015
LIGHT RAIN SHOWERS AND DRIZZLE WITH MVFR CONDITIONS ARE EXPECTED
OVERNIGHT AS A MID LEVEL SHORTWAVE TRACKS THROUGH THE WESTERN
GREAT LAKES. SOME IFR CONDITIONS ARE ALSO POSSIBLE AT TIMES WITH
HEAVIER SHOWERS. GIVEN THE EXPANSIVE CLOUD COVER WIDESPREAD FOG IS
NOT ANCITIPATED WITH THIS SET OF TAFS OVERNIGHT. A WARM FRONT
WILL LIFT NORTH ON TUESDAY...BRINGING MORE SHOWERS AND
THUNDERSTORMS TO THE AREA. A BETTER CHANCE FOR SHOWERS AND
THUNDERSTORMS WILL OCCUR TUESDAY EVENING WHEN A LOW PRESSURE
SYSTEM APPROACHES THE UPPER MISSISSIPPI VALLEY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......MG
AVIATION.......KURIMSKI
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1157 AM EDT TUE AUG 18 2015
.SYNOPSIS...
THE REGION REMAINS IN BETWEEN HIGH PRESSURE OVER THE CANADIAN
MARITIMES AND A COLD FRONT SLOWLY ADVANCING TO THE EAST FROM THE
MIDWEST THROUGH THURSDAY NIGHT. THIS FRONT THEN SLOWLY CROSSES
THE TRI- STATE FRIDAY AND FRIDAY NIGHT. THE FRONT STALLS OUT JUST
TO THE EAST AND SOUTH OF THE AREA...AND WEAKENS... AS HIGH
PRESSURE SLOWLY BUILDS IN FROM THE NORTHEAST THROUGH THE WEEKEND.
ANOTHER COLD FRONT APPROACHES FROM THE WEST ON MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
VERY WARM AND HUMID AIRMASS REMAINS OVER THE REGION WITH SFC TEMPS
IN THE UPPER 80S TO LOW 90S AND SFC DEWPOINTS GENERALLY IN THE 60S
TO NEAR 70. AS A RESULT...MU CAPE VALUES FROM 0-10 KM RANGE FROM
1500-2000 J/KG.
12Z NAM HAS BACKED OFF ON SHRA/TSRA OVER THE AREA THIS
AFTERNOON...BUT THE LATEST HRRR KEEPS SCT SHRA/TSRA ACROSS
INTERIOR PORTIONS OF SOUTHERN CT. WITH AFTERNOON SEA BREEZES
DEVELOPING AND POSSIBLE OUTFLOW BOUNDARIES FROM ANY DEVELOPING
STORMS UPSTREAM...WILL KEEP CHANCE POPS IN THOSE AREAS.
THE HEAT INDEX THIS AFTERNOON WILL TOP OFF IN THE LOW 90S ACROSS
MUCH OF THE CWA...AND INTO THE MID 90S FOR NE NJ AND POSSIBLY FOR
PARTS OF NYC.
THERE IS A MODERATE RISK OF RIP CURRENTS FORECAST FOR THE OCEAN
BEACHES TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
ANY LINGERING SHOWERS...MOST LIKELY CONFINED TO NORTH OF THE
CITY...SHOULD END BY MIDNIGHT AS THE ATMOSPHERE STABILIZES. WINDS
BACK A LITTLE MORE TOWARDS SSE...MAINTAINING PLENTY OF LOW LEVEL
MOISTURE. NOT SO SURE WE SEE STRATUS WITH WATER TEMPS SO
WARM...AND WOULD HAVE LIKE TO SEEN THE LOW LEVEL MOISTURE PROGGED
DEEPER TO PUT IT INTO THE GRIDS...BUT WILL AT LEAST KEEP IN PATCHY
FOG FOR THE SUBURBS LATE AT NIGHT. THAT SAID...SOME STRATUS IS NOT
OUT OF THE QUESTION.
WITH WINDS CONTINUING TO BACK A LITTLE MORE ACROSS THE CWA AND
MOISTURE WELL AHEAD OF A COLD FRONT OVER THE GREAT LAKES SHIFTING
CLOSER...THE BEST MOISTURE CONVERGENCE AND CHANCE OF SHOWERS/TSTMS
ENDS UP BEING MOSTLY WEST OF THE HUDSON DURING WEDNESDAY. STORM
MOTION WILL BE SLOW ONCE AGAIN...SO LOCALLY HEAVY DOWNPOURS WILL BE
POSSIBLE. HIGHS TEMP FORECAST IS SLIGHTLY WARMER THAN A MAV/NAM
MOS BLEND.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
NORTHERN STREAM RIDGING SLOWLY EXITS TO THE NORTHEAST WEDNESDAY
NIGHT AND THURSDAY. SUBSIDENCE FROM THE RIDGE WILL HELP TO LIMIT
POPS TO SLIGHT CHANCE WEDNESDAY NIGHT...AND AT MOST CHANCE ON
THURSDAY. INSTABILITY IN THE WEDNESDAY NIGHT-THURSDAY TIME FRAME IS
VERY WEAK...IF NOT NONE-EXISTENT BASED ON MODEL (AT MOST A FEW
HUNDRED J/KG OF CAPE AND SHOWALTERS GENERALLY ABOVE 3)...SO HAVE
LIMITED MENTION OF THUNDER TO ONLY THOSE AREAS WITH CHANCE POPS (FAR
NW ZONES THURSDAY)...AND THEN CAPPED THE PROBABILITY OF THUNDER TO
SLIGHT CHANCE. GENERALLY EXPECT ANY CONVECTION TO BE OF THE MORE
MISS THAN HIT VARIETY WEDNESDAY NIGHT AND THURSDAY...WITH MOST AREAS
TO THE EAST OF NYC SEEING LITTLE IF ANY PRECIPITATION DURING THIS
TIME FRAME.
FOR LOWS WEDNESDAY NIGHT A BLEND OF ECS/MET/MAV GUIDANCE AND NAM 2-
METER TEMPERATURES WAS USED...WITH VALUES FORECAST TO BE AROUND 5
DEGREES ABOVE NORMAL. A BLEND OF MAV/MET GUIDANCE...MIXING DOWN FROM
975-875 HPA PER BUFKIT SOUNDINGS...AND NAM 2-METER TEMPERATURES WAS
USED FOR HIGHS ON THURSDAY...WITH READINGS EXPECTED TO BE WITHIN A
FEW DEGREES OF EITHER SIDE OF NORMAL.
A NORTHERN STREAM TROUGH LIFTS TO THE N THEN NE THURSDAY NIGHT INTO
FRIDAY EVENING...WITH ITS ASSOCIATED SURFACE COLD FRONT PASSING
THROUGH JUST AHEAD OF IT. SHOULD HAVE SUFFICIENT FORCING MAINLY OVER
WESTERN ZONES TO WARRANT LIKELY POPS THURSDAY NIGHT THERE...WITH
CHANCE POPS OR LESS FARTHER EAST...THEN LIKELY POPS THROUGHOUT ON
FRIDAY...EXCEPT OVER FAR SE ZONES WHERE LIMITED TO CHANCE DUE TO THE
SLOW EASTWARD PROGRESSION OF THE SYSTEM AND THAT THE BEST FORCING IS
LIFTING AWAY FROM THIS AREA.
THE FACT THAT THE BEST FORCING IS LIFTING AWAY FROM THE AREA THE
ENTIRE TIME IS OF SOME CONCERN...AND IS THE REASON WHY POPS WERE NOT
RAISED TO CATEGORICAL. DEPENDING ON EXACTLY HOW THINGS PLAY
OUT...THERE IS SOME POTENTIAL THAT EVEN LIKELY POPS COULD BE
OVERDONE. PROBABILITY OF THUNDER WAS CAPPED AGAIN AT CHANCE DUE TO
CONTINUED LIMITED INSTABILITY IN THE LOW LEVELS. GIVEN THE
OVERALL TREND...HAVE CONTINUED TO MENTION LOCALLY HEAVY RAIN
THURSDAY NIGHT/FRIDAY IN AREAS WITH LIKELY POPS. REFER TO THE
HYDROLOGY SECTION OF THE AFD FOR POTENTIAL QPF AND ANY IMPACTS.
THE WEATHER COULD THEN REMAIN UNSETTLED FROM FRIDAY NIGHT-MONDAY
WITH THE FRONT STALLING OUT NEARBY AND MULTIPLE SHORTWAVES PASSING
OVER THE AREA IN SW FLOW ALOFT. FOR NOW HAVE CHANCE POPS FRIDAY
NIGHT AND SATURDAY WHEN THE COLD FRONT IS AT ITS CLOSEST...THEN
SLIGHT CHANCE POPS SATURDAY NIGHT-MONDAY WITH TWO EXCEPTIONS. THE
FIRST IS SUNDAY WHERE THERE ARE CHANCE POPS OVER THE NW 1/2 OF THE
CWA AS CONVECTION COULD BE DIURNALLY ENHANCED...THEN OVER THE NW 1/3
OF THE AREA ON MONDAY AHEAD OF AN ADVANCING CUTOFF LOW AND
ASSOCIATED TROUGH FORECAST TO MOVE INTO THE GREAT LAKES ON MONDAY.
FOR TEMPERATURES THURSDAY NIGHT-MONDAY A BLEND OF
MEX/MEN/EKD/ECE/ECM/WPC GUIDANCE WAS USED...WITH NAM 2-METER
TEMPERATURES MIXED IN AS WELL FOR THURSDAY NIGHT. LOWS ARE FORECAST
TO REMAIN ABOVE NORMAL IN THIS TIME FRAME WITH HIGHS NEAR TO
SLIGHTLY ABOVE NORMAL.
&&
.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
OFFSHORE HIGH PRESSURE THROUGH THE TAF PERIOD. MAINLY VFR WITH
ANY LOWER CATEGORIES RESULTING FROM NIGHTTIME COASTAL PATCHY
FOG/LOW STRATUS OR ISOLATED SHOWER/THUNDERSTORM ACTIVITY. S FLOW
UNDER 10 KT INCREASES TO 10-15 KT THIS AFTERNOON BEFORE
DIMINISHING AGAIN TONIGHT.
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: MODERATE CONFIDENCE IN FORECAST. WINDS
COULD GUST OCCASIONALLY UP TO 20 KT LATE THIS AFTERNOON AND EARLY
THIS EVENING.
KLGA FCSTER COMMENTS: MODERATE CONFIDENCE IN FORECAST. WINDS
COULD GUST OCCASIONALLY UP TO 20 KT THIS AFTERNOON.
KEWR FCSTER COMMENTS: MODERATE CONFIDENCE IN FORECAST. WINDS
COULD GUST OCCASIONALLY UP TO 20 KT THIS AFTERNOON.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH
IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.
KTEB FCSTER COMMENTS: MODERATE CONFIDENCE IN FORECAST. WINDS
COULD GUST OCCASIONALLY UP TO 15 KT THIS AFTERNOON.
KHPN FCSTER COMMENTS: MODERATE CONFIDENCE IN FORECAST. WINDS
COULD GUST OCCASIONALLY UP TO 15 KT THIS AFTERNOON.
KISP FCSTER COMMENTS: MODERATE CONFIDENCE IN FORECAST. WINDS
COULD GUST OCCASIONALLY UP TO 20 KT THIS AFTERNOON.
.OUTLOOK FOR 12Z WEDNESDAY THROUGH SATURDAY...
.WED...ISOLD-SCT AFTN SHRA/TSTM POSSIBLE MAINLY FROM CITY
TERMINALS ON N/W. S-SW WINDS G15-20KT. MVFR OR LOWER POSSIBLE.
.WED NIGHT-THU...MVFR OR LOWER POSSIBLE WITH A LOW CHC OF SHRA.
RELATIVELY HIGHER CHC THU NEAR CITY TERMINALS AND N/W.
.THU NIGHT-FRI NIGHT...MVFR OR LOWER POSSIBLE IN SHRA/TSTMS.
.SATURDAY...MVFR POSSIBLE WITH A CHANCE OF SHRA/TSTMS.
&&
.MARINE...
PREVAILING WINDS AND SEAS SHOULD REMAIN BELOW SCA CRITERIA
THROUGH WEDNESDAY...BUT A FEW GUSTS TO 25 KT WILL BE POSSIBLE NEAR
THE NY HARBOR ENTRANCE LATE THIS AFTERNOON/EARLY EVENING.
A RELAXED PRESSURE GRADIENT OVER THE REGION WILL KEEP WINDS AT 10 KT
OR LESS WEDNESDAY NIGHT THROUGH SATURDAY. SEAS ON THE COASTAL OCEAN
WATERS SHOULD BE 3 FT OR LESS AND ON THE NON-OCEAN WATERS 1 FT OR
LESS IN THIS TIME FRAME AS A RESULT.
&&
.HYDROLOGY...
ALTHOUGH SHOWER/THUNDERSTORM COVERAGE IS EXPECTED TO BE
RELATIVELY SPARSE TODAY...ANYTHING THAT FORMS WILL LIKELY REMAIN
NEARLY STATIONARY OR MOVE VERY SLOWLY...WITH POTENTIAL TO DUMP A
QUICK ISOLATED 1-2 INCHES OF RAIN. LOCALIZED FLASH FLOODING MAINLY
FOR URBAN AREAS IS POSSIBLE...BUT AGAIN...COVERAGE AND OVERALL
CHANCES OF RAINFALL ARE TOO LOW FOR CONSIDERATION OF A WATCH.
FOR WEDNESDAY...SCATTERED HEAVY SHOWERS AND THUNDERSTORMS MAY
CAUSE MAINLY MINOR URBAN FLOODING.
NO SIGNIFICANT WIDESPREAD PRECIPITATION IS EXPECTED
WEDNESDAY NIGHT AND THURSDAY.
FOR NOW FORECASTING 2/10 TO AROUND 1 INCH OF RAIN THURSDAY NIGHT
AND FRIDAY...WITH HIGHEST AMOUNTS OVER NW ZONES AND LOWEST AMOUNTS
OVER FAR E ZONES. WITH STORM MOTION FORECAST TO BE 5 KT OR
LESS...AND PRECIPITABLE WATERS FORECAST ON AVERAGE TO BE BETWEEN
1.5-2 INCHES THURSDAY NIGHT AND FRIDAY (WITH QUITE A BIT OF
DISCREPANCY BETWEEN INDIVIDUAL MODELS WITH THE NAM GOING BELOW 1.5
INCHES AND THE GFS ABOVE 2 INCHES)...THERE IS THE POTENTIAL FOR
ANY STRONGER STORM TO PRODUCE LOCALLY HEAVY RAINFALL. SINCE STORMS
ARE FORECAST TO BE SLOW MOVING...THERE IS THE POTENTIAL FOR
LOCALIZED MINOR URBAN/POOR DRAINAGE FLOODING.
IF PRECIPITABLE WATERS END UP BEING TOWARDS THE HIGHER END OF THE
RANGE...ESPECIALLY IF THE GFS ENDS UP BEING CORRECT...THEN THERE
WOULD BE THE POTENTIAL FOR LOCALIZED FLASH FLOODING AS
WELL...ESPECIALLY IN URBAN AREAS. CONFIDENCE IN WIDESPREAD FLASH
FLOODING CURRENTLY NOT HIGH ENOUGH TO MENTION IN THE HWO...WITH
LARGE DIFFERENCES IN FORECAST PRECIPITABLE WATERS BEING THE
LIMITING FACTOR.
WHILE THE MAIN THREAT FOR LOCALLY HEAVY RAINFALL IS THURSDAY NIGHT
AND FRIDAY...IT IS POSSIBLE THE THREAT COULD LINGER INTO FRIDAY
NIGHT DEPENDING ON EXACTLY HOW FAST THE COLD FRONT SLIDES TO THE
EAST.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JC/MALOIT
NEAR TERM...MPS
SHORT TERM...JC
LONG TERM...MALOIT
AVIATION...IRD
MARINE...JC/MALOIT
HYDROLOGY...JC/MALOIT
AREA FORECAST DISCUSSION
NWS NEW YORK NY
742 AM EDT TUE AUG 18 2015
.SYNOPSIS...
THE REGION REMAINS IN BETWEEN HIGH PRESSURE OVER THE CANADIAN
MARITIMES AND A COLD FRONT SLOWLY ADVANCING TO THE EAST FROM THE
MIDWEST THROUGH THURSDAY NIGHT. THIS FRONT THEN SLOWLY CROSSES
THE TRI- STATE FRIDAY AND FRIDAY NIGHT. THE FRONT STALLS OUT JUST
TO THE EAST AND SOUTH OF THE AREA...AND WEAKENS... AS HIGH
PRESSURE SLOWLY BUILDS IN FROM THE NORTHEAST THROUGH THE WEEKEND.
ANOTHER COLD FRONT APPROACHES FROM THE WEST ON MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MADE MINOR CHANGES THIS UPDATE TO REFLECT THE LATEST TRENDS IN
OBSERVATIONS AND GUIDANCE. THE FORECAST APPEARS ON TRACK FOR NOW.
DO NOTE THAT LATEST HRRR NOW FAVORS PRECIPITATION FOR THE
REMAINDER OF THE DAY OVER NW ZONES. ALL GUIDANCE AND CURRENT RADAR
TRENDS SUGGEST CURRENT SHRA OVER NE NJ/LOWER HUDSON VALLEY WILL
DISSIPATE WITHIN THE NEXT HOUR OR SO.
UPPER RIDGE AXIS WILL BE TO OUR EAST TODAY. SURFACE BASED CAPES
WILL ONCE AGAIN INCREASE WITH ENOUGH MOISTURE FOR ISO/SCT
SHOWERS/THUNDERSTORMS ALONG SEA BREEZE AND OUTFLOW BOUNDARIES AS
WELL AS DIFFERENTIAL HEATING OVER THE FAR NW ZONES. STEERING FLOW
IS VERY WEAK...SO CELL MOVEMENT WILL BE SLOW WITH THE POTENTIAL OF
LOCALIZED FLOODING. COVERAGE AND PROBABILITY TOO LOW FOR ANY WATCH
CONSIDERATION.
AS FOR HIGH TEMPS...THE AFTERNOON 850MB TEMP IS PROGGED TO BE NEARLY
THE SAME OR ONLY UP TO A DEGREE COOLER THAN IT WAS YESTERDAY
AFTERNOON. EVEN SO...MAV/MET GUIDANCE WOULD SEEM TO BE TOO COOL WITH
HIGH TEMPS AT A FIRST GLANCE. BEST GUESS FOR THIS IS THAT AN
EARLIER/MORE WIDESPREAD FLOW OFF THE WATERS VERSUS YESTERDAY
CONTRIBUTES TO A SHALLOWER MIXING DEPTH AND LOWER 1000-850MB
THICKNESSES THIS AFTERNOON. WENT WITH MAV MOS GUIDANCE FOR MOST
SPOTS...WHICH WAS WARMER THAN NAM MOS IN MOST CASES AND BETTER
REFLECTS CURRENT THINKING.
SURFACE DEWPOINTS AND RESULTANT HEAT INDEX VALUES WILL BE TRICKY. S
TO LOCALLY SE WINDS WOULD HELP KEEP DEWPOINTS UP...BUT ODDLY ENOUGH
MODELS SHOW DRY AIR ADVECTING IN FROM THE SOUTH IN THE UPPER
PORTIONS OF THE BOUNDARY LAYER. THIS COULD HELP DROP THE DEWPOINTS A
COUPLE OF DEGREES IN THE MID TO LATE AFTERNOON HOURS. HAVE LOWERED
DEWPOINT FORECAST BY A DEGREE OR TWO FROM A GUIDANCE BLEND DURING
THESE HOURS. NO CONCERNS THEREFORE FOR ANY HEAT
ADVISORIES...ESPECIALLY WITH HIGH TEMPS AROUND 90 FOR THE WARMEST
SPOTS.
THERE IS A MODERATE RISK OF RIP CURRENTS FORECAST FOR THE OCEAN
BEACHES TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
ANY LINGERING SHOWERS...MOST LIKELY CONFINED TO NORTH OF THE CITY...
SHOULD END BY MIDNIGHT AS THE ATMOSPHERE STABILIZES. WINDS BACK A
LITTLE MORE TOWARDS SSE...MAINTAINING PLENTY OF LOW LEVEL MOISTURE.
NOT SO SURE WE SEE STRATUS WITH WATER TEMPS SO WARM...AND WOULD HAVE
LIKE TO SEEN THE LOW LEVEL MOISTURE PROGGED DEEPER TO PUT IT INTO
THE GRIDS...BUT WILL AT LEAST KEEP IN PATCHY FOG FOR THE SUBURBS
LATE AT NIGHT. THAT SAID...SOME STRATUS IS NOT OUT OF THE QUESTION.
WITH WINDS CONTINUING TO BACK A LITTLE MORE ACROSS THE CWA AND
MOISTURE WELL AHEAD OF A COLD FRONT OVER THE GREAT LAKES SHIFTING
CLOSER...THE BEST MOISTURE CONVERGENCE AND CHANCE OF SHOWERS/TSTMS
ENDS UP BEING MOSTLY WEST OF THE HUDSON DURING WEDNESDAY. STORM
MOTION WILL BE SLOW ONCE AGAIN...SO LOCALLY HEAVY DOWNPOURS WILL BE
POSSIBLE. HIGHS TEMP FORECAST IS SLIGHTLY WARMER THAN A MAV/NAM
MOS BLEND.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
NORTHERN STREAM RIDGING SLOWLY EXITS TO THE NORTHEAST WEDNESDAY
NIGHT AND THURSDAY. SUBSIDENCE FROM THE RIDGE WILL HELP TO LIMIT
POPS TO SLIGHT CHANCE WEDNESDAY NIGHT...AND AT MOST CHANCE ON
THURSDAY. INSTABILITY IN THE WEDNESDAY NIGHT-THURSDAY TIME FRAME IS
VERY WEAK...IF NOT NONE-EXISTENT BASED ON MODEL (AT MOST A FEW
HUNDRED J/KG OF CAPE AND SHOWALTERS GENERALLY ABOVE 3)...SO HAVE
LIMITED MENTION OF THUNDER TO ONLY THOSE AREAS WITH CHANCE POPS (FAR
NW ZONES THURSDAY)...AND THEN CAPPED THE PROBABILITY OF THUNDER TO
SLIGHT CHANCE. GENERALLY EXPECT ANY CONVECTION TO BE OF THE MORE
MISS THAN HIT VARIETY WEDNESDAY NIGHT AND THURSDAY...WITH MOST AREAS
TO THE EAST OF NYC SEEING LITTLE IF ANY PRECIPITATION DURING THIS
TIME FRAME.
FOR LOWS WEDNESDAY NIGHT A BLEND OF ECS/MET/MAV GUIDANCE AND NAM 2-
METER TEMPERATURES WAS USED...WITH VALUES FORECAST TO BE AROUND 5
DEGREES ABOVE NORMAL. A BLEND OF MAV/MET GUIDANCE...MIXING DOWN FROM
975-875 HPA PER BUFKIT SOUNDINGS...AND NAM 2-METER TEMPERATURES WAS
USED FOR HIGHS ON THURSDAY...WITH READINGS EXPECTED TO BE WITHIN A
FEW DEGREES OF EITHER SIDE OF NORMAL.
A NORTHERN STREAM TROUGH LIFTS TO THE N THEN NE THURSDAY NIGHT INTO
FRIDAY EVENING...WITH ITS ASSOCIATED SURFACE COLD FRONT PASSING
THROUGH JUST AHEAD OF IT. SHOULD HAVE SUFFICIENT FORCING MAINLY OVER
WESTERN ZONES TO WARRANT LIKELY POPS THURSDAY NIGHT THERE...WITH
CHANCE POPS OR LESS FARTHER EAST...THEN LIKELY POPS THROUGHOUT ON
FRIDAY...EXCEPT OVER FAR SE ZONES WHERE LIMITED TO CHANCE DUE TO THE
SLOW EASTWARD PROGRESSION OF THE SYSTEM AND THAT THE BEST FORCING IS
LIFTING AWAY FROM THIS AREA.
THE FACT THAT THE BEST FORCING IS LIFTING AWAY FROM THE AREA THE
ENTIRE TIME IS OF SOME CONCERN...AND IS THE REASON WHY POPS WERE NOT
RAISED TO CATEGORICAL. DEPENDING ON EXACTLY HOW THINGS PLAY
OUT...THERE IS SOME POTENTIAL THAT EVEN LIKELY POPS COULD BE
OVERDONE. PROBABILITY OF THUNDER WAS CAPPED AGAIN AT CHANCE DUE TO
CONTINUED LIMITED INSTABILITY IN THE LOW LEVELS. GIVEN THE
OVERALL TREND...HAVE CONTINUED TO MENTION LOCALLY HEAVY RAIN
THURSDAY NIGHT/FRIDAY IN AREAS WITH LIKELY POPS. REFER TO THE
HYDROLOGY SECTION OF THE AFD FOR POTENTIAL QPF AND ANY IMPACTS.
THE WEATHER COULD THEN REMAIN UNSETTLED FROM FRIDAY NIGHT-MONDAY
WITH THE FRONT STALLING OUT NEARBY AND MULTIPLE SHORTWAVES PASSING
OVER THE AREA IN SW FLOW ALOFT. FOR NOW HAVE CHANCE POPS FRIDAY
NIGHT AND SATURDAY WHEN THE COLD FRONT IS AT ITS CLOSEST...THEN
SLIGHT CHANCE POPS SATURDAY NIGHT-MONDAY WITH TWO EXCEPTIONS. THE
FIRST IS SUNDAY WHERE THERE ARE CHANCE POPS OVER THE NW 1/2 OF THE
CWA AS CONVECTION COULD BE DIURNALLY ENHANCED...THEN OVER THE NW 1/3
OF THE AREA ON MONDAY AHEAD OF AN ADVANCING CUTOFF LOW AND
ASSOCIATED TROUGH FORECAST TO MOVE INTO THE GREAT LAKES ON MONDAY.
FOR TEMPERATURES THURSDAY NIGHT-MONDAY A BLEND OF
MEX/MEN/EKD/ECE/ECM/WPC GUIDANCE WAS USED...WITH NAM 2-METER
TEMPERATURES MIXED IN AS WELL FOR THURSDAY NIGHT. LOWS ARE FORECAST
TO REMAIN ABOVE NORMAL IN THIS TIME FRAME WITH HIGHS NEAR TO
SLIGHTLY ABOVE NORMAL.
&&
.AVIATION /11Z TUESDAY THROUGH SATURDAY/...
OFFSHORE BROAD HIGH PRESSURE PERSISTS THROUGH THE TAF PERIOD.
MAINLY VFR WITH ANY LOWER CATEGORIES BEING DUE TO PATCHY FOG/LOW
STRATUS OR SHOWER/THUNDERSTORM ACTIVITY. THE SHOWER/THUNDERSTORM
ACTIVITY WILL BE LOW COVERAGE PRIMARILY N/W OF CITY TERMINALS.
THE PATCHY FOG/LOW STRATUS WILL BE PRIMARILY LATE TONIGHT INTO
WEDNESDAY MORNING. S FLOW UNDER 10 KT INCREASES TO 10-15 KT THIS
AFTERNOON BEFORE DIMINISHING AGAIN TONIGHT.
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: MODERATE CONFIDENCE IN FORECAST. WINDS
COULD GUST OCCASIONALLY UP TO 20 KT LATE THIS AFTERNOON AND EARLY
THIS EVENING.
KLGA FCSTER COMMENTS: MODERATE CONFIDENCE IN FORECAST. WINDS
COULD GUST OCCASIONALLY UP TO 20 KT THIS AFTERNOON.
KEWR FCSTER COMMENTS: MODERATE CONFIDENCE IN FORECAST. WINDS
COULD GUST OCCASIONALLY UP TO 20 KT THIS AFTERNOON.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH
IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.
KTEB FCSTER COMMENTS: MODERATE CONFIDENCE IN FORECAST. WINDS
COULD GUST OCCASIONALLY UP TO 15 KT THIS AFTERNOON.
KHPN FCSTER COMMENTS: MODERATE CONFIDENCE IN FORECAST. WINDS
COULD GUST OCCASIONALLY UP TO 15 KT THIS AFTERNOON.
KISP FCSTER COMMENTS: MODERATE CONFIDENCE IN FORECAST. WINDS
COULD GUST OCCASIONALLY UP TO 20 KT THIS AFTERNOON.
.OUTLOOK FOR 12Z WEDNESDAY THROUGH SATURDAY...
.WED...ISOLD-SCT AFTN SHRA/TSTM POSSIBLE MAINLY FROM CITY
TERMINALS ON N/W. S-SW WINDS G15-20KT. MVFR OR LOWER POSSIBLE.
.WED NIGHT-THU...MVFR OR LOWER POSSIBLE WITH A LOW CHC OF SHRA.
RELATIVELY HIGHER CHC THU NEAR CITY TERMINALS AND N/W.
.THU NIGHT-FRI NIGHT...MVFR OR LOWER POSSIBLE IN SHRA/TSTMS.
.SATURDAY...MVFR POSSIBLE WITH A CHANCE OF SHRA/TSTMS.
&&
.MARINE...
MADE MINOR CHANGES THIS UPDATE TO REFLECT THE LATEST TRENDS IN
OBSERVATIONS AND GUIDANCE. THE FORECAST APPEARS ON TRACK.
PREVAILING WINDS AND SEAS SHOULD REMAIN BELOW SCA CRITERIA THROUGH
WEDNESDAY...BUT A FEW GUSTS TO 25 KT WILL BE POSSIBLE NEAR THE NY
HARBOR ENTRANCE LATE THIS AFTERNOON/EARLY EVENING.
A RELAXED PRESSURE GRADIENT OVER THE REGION WILL KEEP WINDS AT 10 KT
OR LESS WEDNESDAY NIGHT THROUGH SATURDAY. SEAS ON THE COASTAL OCEAN
WATERS SHOULD BE 3 FT OR LESS AND ON THE NON-OCEAN WATERS 1 FT OR
LESS IN THIS TIME FRAME AS A RESULT.
&&
.HYDROLOGY...
ALTHOUGH SHOWER/THUNDERSTORM COVERAGE IS EXPECTED TO BE
RELATIVELY SPARSE TODAY...ANYTHING THAT FORMS WILL LIKELY REMAIN
NEARLY STATIONARY OR MOVE VERY SLOWLY...WITH POTENTIAL TO DUMP A
QUICK ISOLATED 1-2 INCHES OF RAIN. LOCALIZED FLASH FLOODING MAINLY
FOR URBAN AREAS IS POSSIBLE...BUT AGAIN...COVERAGE AND OVERALL
CHANCES OF RAINFALL ARE TOO LOW FOR CONSIDERATION OF A WATCH.
FOR WEDNESDAY...SCATTERED HEAVY SHOWERS AND THUNDERSTORMS MAY
CAUSE MAINLY MINOR URBAN FLOODING.
NO SIGNIFICANT WIDESPREAD PRECIPITATION IS EXPECTED
WEDNESDAY NIGHT AND THURSDAY.
FOR NOW FORECASTING 2/10 TO AROUND 1 INCH OF RAIN THURSDAY NIGHT
AND FRIDAY...WITH HIGHEST AMOUNTS OVER NW ZONES AND LOWEST AMOUNTS
OVER FAR E ZONES. WITH STORM MOTION FORECAST TO BE 5 KT OR
LESS...AND PRECIPITABLE WATERS FORECAST ON AVERAGE TO BE BETWEEN
1.5-2 INCHES THURSDAY NIGHT AND FRIDAY (WITH QUITE A BIT OF
DISCREPANCY BETWEEN INDIVIDUAL MODELS WITH THE NAM GOING BELOW 1.5
INCHES AND THE GFS ABOVE 2 INCHES)...THERE IS THE POTENTIAL FOR
ANY STRONGER STORM TO PRODUCE LOCALLY HEAVY RAINFALL. SINCE STORMS
ARE FORECAST TO BE SLOW MOVING...THERE IS THE POTENTIAL FOR
LOCALIZED MINOR URBAN/POOR DRAINAGE FLOODING.
IF PRECIPITABLE WATERS END UP BEING TOWARDS THE HIGHER END OF THE
RANGE...ESPECIALLY IF THE GFS ENDS UP BEING CORRECT...THEN THERE
WOULD BE THE POTENTIAL FOR LOCALIZED FLASH FLOODING AS
WELL...ESPECIALLY IN URBAN AREAS. CONFIDENCE IN WIDESPREAD FLASH
FLOODING CURRENTLY NOT HIGH ENOUGH TO MENTION IN THE HWO...WITH
LARGE DIFFERENCES IN FORECAST PRECIPITABLE WATERS BEING THE
LIMITING FACTOR.
WHILE THE MAIN THREAT FOR LOCALLY HEAVY RAINFALL IS THURSDAY NIGHT
AND FRIDAY...IT IS POSSIBLE THE THREAT COULD LINGER INTO FRIDAY
NIGHT DEPENDING ON EXACTLY HOW FAST THE COLD FRONT SLIDES TO THE
EAST.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JC/MALOIT
NEAR TERM...MALOIT/JC
SHORT TERM...JC
LONG TERM...MALOIT
AVIATION...JM
MARINE...JC/MALOIT
HYDROLOGY...JC/MALOIT
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
623 AM EDT TUE AUG 18 2015
.SYNOPSIS...
AN AREA OF LOW PRESSURE WILL TRACK ACROSS THE CENTRAL PLAINS TODAY
INTO TONIGHT, THEN ACROSS THE UPPER GREAT LAKES REGION WEDNESDAY. AS
THIS LOW MOVES INTO CANADA THURSDAY, ITS ASSOCIATED COLD FRONT IS
FORECAST TO SLOWLY MOVE THROUGH OUR AREA THURSDAY NIGHT AND FRIDAY.
HIGH PRESSURE THEN BUILDS INTO OUR AREA DURING THE WEEKEND, WITH THE
NEXT COLD FRONT ARRIVING LATE MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE GFS INITIALIZATION AT 500MB LOOKED CLOSER THAN THE WRF-NMMB.
AT 850MB, THE INITIALIZATION ERRORS BY BOTH MODELS WERE GENERALLY
1C TOO COLD, WHILE AT 925MB IT WAS A SMATTERING OF 1C ERRORS IN
BOTH DIRECTIONS. ANOTHER NIGHT, A DP/DT IN THE OPPOSITE DIRECTION
AGAIN AS THE MODEL PROGRESSIVE TREND IS SLOWER.
IN THE NEAR TERM ITS A RACE BETWEEN INSTABILITY BEING TAPPED AND
DRIER AIR ARRIVING FROM THE DELMARVA PENINSULA WATERS. COMPLICATING
THE PICTURE FURTHER IS THE SHORT WAVE OVER WEST VIRGINIA AND THE
NEVER SAY DIE TRULY ISOLATED SHOWERS CURRENTLY IN OUR CWA. WHEN ALL
OF THE MEASURABLE VOTES ARE TALLIED THE PAST TWO DAYS, WE WERE VERY
CLOSE TO OUR 15 PCT POP MENTION THRESHOLD ACROSS OUR CWA BOTH DAYS.
BUT OVERALL THERE WAS MORE THAN WHAT WE EXPECTED EVEN IN TERMS OF
ISOLATED PCPN AND THIS SWAYED OUR DECISION FOR TODAY GIVEN WE ARE
IN THE SAME REGIME.
THUS WE ARE BANKING ON A HAT TRICK OF OVERPERFORMANCE VS THE
CONVECTING MESOSCALE MODELS WHICH ONCE AGAIN HAVE NEXT TO NOTHING.
THE SHORT WAVE BANKING AGAINST THE NJ SHORE THAT CAUSED THE
ENHANCED SHOWERS IN PARTS OF THE LOWER RARITAN AND PASSAIC BASINS
IS PREDICTED TO WEAKEN. HRRR HAD A COUPLE OF GOOD RUNS INITIATING
THE PCPN AND IT HAS IT THRU OR DISSIPATED BY 12Z.
THEN IT WOULD APPEAR THE NEXT POTENTIAL ROUND OF ISOLATED
PRECIPITATION SHOULD COMMENCE AROUND NOON TIME. IF PCPN WERE TO
OCCUR IN THE SERN PART OF OUR CWA, HIEST CHANCE WOULD BE THIS
MORNING WHEN MIXED LAYER CAPES ABOVE THE CIN ARE MAXIMIZED. AFTER
THAT ITS ROUGHLY NORTH OF THE PA TURNPIKE AND NORTHWEST OF I287 IN
NJ AS OUR DIVIDING LINE BETWEEN POPS AND NONE AS DRIER AIR ALOFT
ARRIVES.
LATE IN THE DAY, THE ADDED ELEMENT OF THE WESTVA SHORT WAVE BRINGS
POPS INTO DELMARVA. LIKE THE PAST TWO DAYS, PREDICTED BULK SHEAR
VALUES ARE LESS THAN 15 KNOTS. MID LEVEL LAPSE RATES ARE SLIGHTLY
BETTER, AROUND 5.5C/KM, BUT THAT BAR WAS SET VERY LOW ALSO. A REPEAT
OF THE PAST TWO DAYS WITH SLOW MOVING SHOWERS AND TSTMS, ONE OR TWO
OF WHICH MIGHT REQUIRE A FLOOD ADVISORY. STRONG WIND GUSTS AND
SEVERE POTENTIAL ARE MUCH LOWER THAN AVERAGE FOR AN AUGUST AFTERNOON
WITH TSTMS AROUND.
TEMPERATURES, ANOTHER DAY OF 90S FOR A CHUNK OF OUR CWA. BUT, THE
AIR MASS IS SLIGHTLY COOLER AND IN QUOTES COOLER AIR IS WRAPPING
AROUND THE OFFSHORE HIGH INTO OUR AREA. IN ADDITION, THE SKY WILL
NOT BE AS CLEAN WITH UPSTREAM CIRRUS HEADING OUR WAY AND ALTOCU
AROUND EARLY THIS MORNING. THE GFS PREDICTED 850MB TEMP DROP THIS
AFTERNOON HAS NO UPSTREAM HISTORY. IN GENERAL MAX TEMPS HAVE BEEN
AVERAGING AROUND 2F HIGHER THAN STAT GUIDANCE THE PAST COUPLE OF
DAYS AND WE USED THIS FORMULA AGAIN TODAY.
MAX TEMPS ABOUT A DEGREE OR TWO COOLER THAN YESTERDAY COUPLED WITH
SIMILAR TO SLIGHTLY HIGHER DEW POINTS SHOULD RESULT IN HEAT INDEX
VALUES VERY SIMILAR TO YESTERDAY, PEAKING IN THE MID 90S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
THE SHORT WAVES HAVE TO RUN THEIR COURSE OVERNIGHT. WITH THE RIDGE
AXIS GONE, THERE IS NOTHING TO IMPEDE THEIR MOTION INTO OUR CWA.
THE WEAKENING TREND LOOKS REASONABLE GIVEN THAT INSTABILITY IS NOT
PREDICTED TO INCREASE OVERNIGHT. STILL A PAIR OF SHORT WAVES, THE
ONE IN WEST VIRGINIA AND A SECOND FARTHER WEST IN THE OHIO VALLEY
SHOULD KEEP SOME LOW CHANCE OF SHOWERS AND TSTMS GOING FOR MOST OF
THE NIGHT.
THE MOISTENING TREND CONTINUING WITH THE SOUTHEAST TO SOUTH FLOW AND
MODEL SOUNDINGS ARE SUGGESTING LOW CLOUDS MAY FORM OVERNIGHT. THIS
SHOULD KEEP MIN TEMPS RELATIVELY HIGHER. THE INCREASING DEW POINTS
WILL LIKELY ACCOMPLISH THAT WHETHER THE CLOUDS FORM OR NOT. MINS NOT
THAT FAR FROM STAT GUIDANCE.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
THE SYNOPTIC SETUP IS COMPRISED OF AN UPPER-LEVEL RIDGE THAT HANGS
ON FOR AWHILE IN THE WESTERN ATLANTIC TOWARD THE CANADIAN MARITIMES,
MEANWHILE A STRONG UPPER-LEVEL TROUGH/CLOSED LOW MOVES ACROSS THE
NORTHERN PLAINS TO THE GREAT LAKES WEDNESDAY. THIS FEATURE LOOKS TO
BE DEFLECTED INTO CANADA AS THE UPPER-LEVEL RIDGE HOLDS INTO THE
CANADIAN MARITIMES. THE RIDGE IS FORECAST TO GRADUALLY WEAKEN WITH A
BROAD TROUGH FROM THE PLAINS TO THE GREAT LAKES. THIS MAY THEN
AMPLIFY FROM THE MIDWEST AND GREAT LAKES OVER THE WEEKEND, WHICH
DRIVES A COLD FRONT INTO OUR AREA LATE MONDAY. A SLOW MOVING COLD
FRONT HOWEVER LATE THURSDAY AND FRIDAY MAY RESULT IN LOCALLY HEAVY
RAIN GIVEN PW VALUES SURGING TO AROUND 2 INCHES. WE USED A MODEL
BLEND FOR WEDNESDAY INTO FRIDAY, THEN BLENDED IN THE 00Z WPC GUIDANCE
WITH CONTINUITY.
FOR WEDNESDAY...HIGH PRESSURE TO OUR EAST WILL MAINTAIN A SOUTHERLY
FLOW OF WARM AND MOIST AIR ACROSS THE AREA. AN UPPER-LEVEL TROUGH
CLOSING OFF IN THE MIDWEST TO THE UPPER GREAT LAKES WILL DRIVE A
COLD FRONT EASTWARD. A WEAK WARM FRONT COMBINED WITH SOME LIFT MAY
RESULT IN SOME CONVECTION ESPECIALLY FOR THE INLAND AREAS. THE
COVERAGE DOES NOT APPEAR TO BE MUCH WITH MOST OF THE BETTER LIFT
REMAINING TO OUR WEST. THEREFORE, WE KEPT SLIGHT CHC TO LOW CHC POPS
IN FOR THE IDEA OF ISOLATED TO SCATTERED CONVECTION DEVELOPING. MORE
CLOUDINESS AND A SOUTHEASTERLY LOW-LEVEL FLOW SHOULD RESULT IN SOME
COOLING, HOWEVER IT WILL BE HUMID.
FOR THURSDAY AND FRIDAY...A CLOSED LOW IS FORECAST TO MOVE INTO
CANADA AS RIDGING HOLDS INTO THE CANADIAN MARITIMES. THIS WILL TAKE
THE SURFACE LOW WELL TO OUR NORTHWEST WITH ITS ASSOCIATED COLD FRONT
SLOWLY MOVING THROUGH THURSDAY NIGHT AND FRIDAY. THERE IS PLENTY OF
MOISTURE IN PLACE WITH PW VALUES SURGING TO AROUND 2 INCHES, HOWEVER
THE BULK OF THE LARGE SCALE LIFT IS FORECAST TO BE REMOVED FROM OUR
AREA DUE TO THE UPPER-LEVEL SYSTEM TRACKING SO FAR TO OUR WEST AND
NORTH.
A CYCLONICALLY CURVED 500 MB JET IS FORECAST TO LIFT UP THE OHIO
VALLEY AND ACROSS WESTERN/CENTRAL NEW YORK AND PENNSYLVANIA. THIS
PLACES OUR WESTERN ZONES CLOSE TO THE ENTRANCE REGION FOR A TIME
LATE THURSDAY INTO FRIDAY MORNING. THIS TIMING MAY CHANGE THOUGH
DEPENDING ON THE ACTUAL SPEED OF THE ENTIRE SYSTEM. AS A RESULT,
SOME ENHANCED LIFT MAY GLANCE OUR AREA INTO FRIDAY WITH A LINE OR
BROKEN LINE OF HEAVY RAIN PRODUCING CONVECTION POTENTIALLY AIDED BY
A FRONTAL CONVERGENCE ZONE. THE LOW-LEVEL FLOW IS FROM THE SOUTHEAST
BUT GENERALLY ON THE LIGHTER SIDE, WHICH COULD FAVOR SOME
BACKBUILDING/TRAINING CONVECTION WITHIN AN ENVIRONMENT CHARACTERIZED
BY A TALL AND THIN CAPE PROFILE. THE DETAILS ARE NOT ALL THAT CLEAR
THOUGH AS WE HAVE SOME CONCERN THE CONVECTION COULD BE MORE LIMITED
GIVEN THE MAIN DYNAMICS PASSING WELL TO OUR WEST AND NORTH. HOWEVER,
THERE STILL REMAINS THE POTENTIAL FOR INCREASING CONVECTIVE COVERAGE
WITH LOCALLY VERY HEAVY RAINFALL. A MENTION WILL REMAIN IN THE
HAZARDOUS WEATHER OUTLOOK.
FOR SATURDAY AND SUNDAY...A COLD FRONT SHOULD BE JUST OFFSHORE TO
START SATURDAY WITH THE FRONT POSSIBLY STALLING AS THE PARENT UPPER-
LEVEL TROUGH LIFTS WELL UP INTO CANADA. THIS ALLOWS SURFACE HIGH
PRESSURE TO BUILD INTO THE AREA, ALTHOUGH IT SHOULD WEAKEN SOME
DURING SUNDAY AS IT STARTS TO SHIFT OFFSHORE. SINCE WE ARE REMOVED
FROM THE AFOREMENTIONED MAIN UPPER-LEVEL TROUGH BUT THE SURFACE
FRONT EASES OFFSHORE, WE HAVE SOME SLIGHT CHC TO LOW CHC POPS ACROSS
THE EAST SATURDAY, THEN SLIGHT CHC EVERYWHERE ON SUNDAY. OVERALL,
THE WEEKEND FOR MOST ATTM LOOKS TO BE DRY. A COOLER AIRMASS IS
EXPECTED TO SETTLE IN FOLLOWING THE FRONTAL PASSAGE, WITH SOME
LOWERING OF THE DEW POINTS ESPECIALLY THE FARTHER INLAND ONE GOES.
FOR MONDAY...ANOTHER AMPLIFYING UPPER-LEVEL TROUGH IS FORECAST TO
CRUISE ACROSS THE NORTHERN PLAINS TO THE GREAT LAKES. THIS WILL
DRIVE LOW PRESSURE MAINLY NORTH OF THE GREAT LAKES, AND ITS
ASSOCIATED COLD FRONT ARRIVES IN OUR AREA LATE. SOME CONVECTION
SHOULD ACCOMPANY THE FRONT, HOWEVER ONCE AGAIN THE MAIN FORCING WITH
THE PARENT UPPER-LEVEL TROUGH MAY END UP BEING REMOVED FROM OUR
AREA. THIS MAY LIMIT THE CONVECTIVE CHCS FOR OUR AREA AS A RESULT.
&&
.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
THROUGH 14Z TODAY...A STRATUS DECK NEAR THE MVFR/IFR THRESHOLD
THAT FORMED WEST AND SOUTHWEST OF KPHL HAS EXPANDED AND IS
SPREADING INTO THE KPHL METRO AIRPORTS. EXPECTATIONS ARE THAT THIS
DECK SHOULD DISSIPATE BY 13Z OR 14Z. ANY MVFR TO LOCALLY IFR FOG
SHOULD BE GONE BY 12Z. ABOVE THESE CLOUDS AND RESTRICTIONS
GENERALLY JUST A FEW MID AND HIGH LEVEL CLOUDS WILL BE AROUND.
WINDS WILL BE SOUTH OR LIGHT AND VARIABLE.
AFTER 14Z THIS MORNING...VFR WITH A SOUTH WIND INCREASING TO 5 TO
10 KNOTS. FEW TO SCATTERED CUMULUS AT 5K TO 6K SHOULD START
FORMING.
THIS AFTERNOON INTO EARLY EVENING...FEW TO SCATTERED CUMULUS
CONTINUING WITH CIRRUS ABOVE. SOUTH TO SOUTHEAST WINDS AVERAGING
CLOSER TO 10 KNOTS. LIKE THE PAST TWO DAYS, WIDELY SCATTERED
SHWRS AND TSTMS ARE EXPECTED TO DEVELOP, BUT CONFIDENCE ABOUT THEM
AFFECTING ANY OF THE TERMINALS IS LOW AND NOT INCLUDED. GREATEST
COVERAGE SHOULD BE AT NORTHWEST AIRPORTS.
OVERNIGHT...ONE OF OUR GUIDANCE MODELS IS PREDICTING IFR CIGS TO
FORM AT THE TERMINALS. MOST OTHER GUIDANCE INCLUDING SOME OF THE
NEWER EXPERIMENTAL MODELS WE ARE VIEWING STILL DO NOT. IFR CIGS
ARE PREDICTED NORTH OF KABE AND KTTN.
INITIAL THOUGHT FOR 12Z TAFS IS TO FOLLOW IDEA OF LOWEST (MVFR) CIGS
AT THE TERMINALS WITH THE MOST UPSLOPE/SOUTH FLOW (KABE, KRDG AND
KTTN). OTHER TERMINALS, WE KEPT CIGS MAINLY AT VFR LEVELS.
FARTHER UPSLOPE AIRPORTS IN THE POCONOS AND NORTHWEST NEW JERSEY
MIGHT HAVE IFR CIGS. CONFIDENCE ABOUT IFR CIG OCCURRING AT THE
TERMINALS AND KPHL IS LOW. WE WILL ALSO BRING IN SOME LIGHT FOG
(MVFR RESTRICTIONS) TO MOST NON URBAN TERMINALS BY WEDNESDAY
MORNING. SOUTHEAST WINDS SHOULD AVERAGE 5 KNOTS OR LESS.
OUTLOOK...
WEDNESDAY...VFR OVERALL. THERE COULD BE SOME MVFR/IFR CONDITIONS TO
START DUE TO LOW CLOUDS OR FOG, THEN POSSIBLY LOCALLY AGAIN THROUGH
THE DAY AND EVENING WITH A FEW SHOWERS OR THUNDERSTORMS.
THURSDAY AND FRIDAY...SHOWERS AND THUNDERSTORMS MAY BECOME NUMEROUS
FOR A TIME WITH A SLOW MOVING COLD FRONT. THIS WILL RESULT IN TIMES
OF MVFR/IFR CONDITIONS. A WIND SHIFT TO THE NORTHWEST SHOULD OCCUR
WITH THE PASSAGE OF A COLD FRONT THURSDAY NIGHT AND FRIDAY.
SATURDAY...VFR OVERALL AS HIGH PRESSURE BUILDS IN.
&&
.MARINE...
SUB SMALL CRAFT ADVISORY CONDITIONS ARE PREDICTED TO CONTINUE TODAY
AND TONIGHT. HOWEVER, A STRONGER SOUTHERLY GRADIENT (BECOMING SE
IN DELAWARE BAY) WILL BRING WIND GUSTS TO AROUND 20 KNOTS LATER THIS
AFTERNOON INTO EVENING BEFORE DECREASING AGAIN. WAVE WATCH GUIDANCE
WHICH NORMALLY IS QUITE BULLISH WITH SOUTHERLY FLOW SEAS REMAINS
SUBDUED WITH SUB SMALL CRAFT ADVISORY SEAS.
OUTLOOK...
WEDNESDAY THROUGH FRIDAY...THE WINDS AND SEAS ARE ANTICIPATED TO
REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA AS A COLD FRONT SLOWLY
CROSSES THE AREA. A FEW THUNDERSTORMS COULD PRODUCE A LOCALLY STRONG
WIND GUST MAINLY LATE THURSDAY AND FRIDAY. THE PASSAGE OF THE COLD
FRONT FRIDAY SHOULD RESULT IN THE WINDS SHIFTING TO NORTHERLY.
SATURDAY...THE WINDS AND SEAS SHOULD REMAIN BELOW SMALL CRAFT
ADVISORY CRITERIA AS HIGH PRESSURE BUILDS IN FROM THE NORTHWEST.
&&
.RIP CURRENTS...
THE IN HOUSE OFFICE REGRESSION EQUATION FOR RIP CURRENT RISKS
CAME UP WITH MODERATE FOR TODAY ALONG THE NJ COAST AND LOW FOR
THE DELAWARE COAST. GIVEN THAT WINDS TODAY ARE EXPECTED TO BE
SLIGHTLY STRONGER AND MORE FROM THE SOUTHEAST, WE WILL USE THIS
RESULT VS THE GFE OUTPUT WHICH WAS LOW ACROSS THE BOARD.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GORSE
NEAR TERM...GIGI
SHORT TERM...GIGI
LONG TERM...GORSE
AVIATION...GIGI/GORSE
MARINE...GIGI/GORSE
RIP CURRENTS...
AREA FORECAST DISCUSSION
NWS DES MOINES IA
700 AM CDT TUE AUG 18 2015
.SHORT TERM /TODAY/...
ISSUED AT 411 AM CDT TUE AUG 18 2015
SHOULD BE A FAIRLY ACTIVE DAY TODAY AS AN UPPER TROUGH OVER THE
NORTHERN PLAINS DEEPENS AND DEVELOPS A CLOSED LOW AS IT MOVES INTO
MN WEDNESDAY MORNING. THERE APPEARS TO BE SEVERAL VORT MAXES OVER
THE PLAINS ASSOCIATED WITH THIS TROUGH WHICH WILL LIKELY SWEEP INTO
NORTHWEST AND NORTH CENTRAL IOWA TODAY. AT THE SURFACE...LOW
PRESSURE OVER NORTH CENTRAL KANSAS IS FORECAST TO LIFT NORTHEAST
INTO WESTERN THEN NORTHWEST IOWA BY LATE AFTERNOON BEFORE MOVING
INTO SOUTH CENTRAL MINNESOTA TONIGHT. A WARM FRONT WILL SHIFT
ACROSS CENTRAL IOWA LATER THIS MORNING INTO THE AFTERNOON BRINGING
THE FIRST ROUND OF PRECIPITATION TO CENTRAL IOWA. SHEAR THIS
MORNING IS NOT OVERLY IMPRESSIVE BUT WILL INCREASE AND DEEPEN WITH
TIME. CAPE VALUES INCREASE THIS MORNING THEN MODELS DIMINISH CAPE
THIS AFTERNOON BEFORE BRIEFLY INCREASING IT AGAIN LATE AFTERNOON
INTO THE EVENING ACROSS THE SOUTHWEST WITH THE PASSAGE OF A COLD
FRONT AS THE SURFACE LOW SHIFTS INTO MN. QC FORCING IS PARTICULARLY
IMPRESSIVE THIS MORNING ESPECIALLY OVER THE NORTH.
PWATS ACROSS THE NORTHWEST INTO NORTH CENTRAL APPROACH 2 INCHES AND
THIS IS OVER LOCATIONS THAT GOT QUITE A BIT OF RAINFALL IN THE
RECENT PAST. THE POTENTIAL FOR HEAVY RAINFALL COMBINED WITH ONE
HOUR FLASH FLOOD GUIDANCE OF 1.6 INCHES OR SO HAS PROMPTED THE
ISSUANCE OF A FLASH FLOOD WATCH ACROSS MUCH OF NORTHWEST INTO NORTH
CENTRAL IOWA FOR TODAY THOUGH I DO EXPECT THE HEAVIEST RAINFALL
FROM MID TO LATE MORNING INTO THE EARLY AFTERNOON.
FURTHER SOUTH WHERE THE BETTER INSTABILITY WILL RESIDE WILL BE A
CONDITIONAL POTENTIAL FOR SEVERE WEATHER FROM MID AFTERNOON INTO
EARLY EVENING WITH THE FRONTAL PASSAGE. THERE IS A FAIR AMOUNT OF
UNCERTAINTY AS TO WHAT THE EXTENT OF THE MORNING CONVECTION WILL BE
AND HOW MUCH WE WILL DESTABILIZE LATER TODAY AS MANY OF THE HI-RES
MODELS DRIBBLE CONVECTION ACROSS US FOR MUCH OF THE DAY BUT THEY DO
IN FACT ALL SUGGEST A SECOND ROUND OF CONVECTION IN THE MID
AFTERNOON THROUGH EARLY TO MID EVENING. AT PRESENT THE HRRR SEEMS
TO HAVE A DECENT HANDLE ON THE PRECIP THOUGH ITS A LITTLE TOO HEAVY
ON THE NORTHWARD EXTENT. THE WRF IS CAPTURING THE SOUTHERN PRECIP
AREA A LITTLE BETTER SO I TRIED TO GO WITH A BLEND OF THOSE TWO
MODELS. THE 00Z NAMDNG ALSO HAD A DECENT HANDLE ON PRECIP BUT THE
06Z RUN IS MISSING THE EXPANDING PRECIP ACROSS THE SOUTHWEST. I
HELD TEMPS DOWN A DEGREE OR TWO WITH ESPECIALLY SOUTH WITH THE
EXPECTED CLOUD COVER AND PRECIP. AS FOR POPS...I WENT FAIRLY HIGH
POPS FOR TODAY. IT SHOULD NOT BE RAINING ALL DAY BUT THERE WILL BE
A FEW ROUNDS OF PRECIP AND THE SCATTERED NATURE OF THE STORMS WILL
MAKE IT VERY DIFFICULT TO PIN DOWN TIME AND LOCATION.
.LONG TERM /TONIGHT THROUGH MONDAY/...
ISSUED AT 411 AM CDT TUE AUG 18 2015
FORECAST CHALLENGE EARLY ON IS WHERE OUR LOW WILL BE AT THE START OF
THE LONG TERM FCST PERIOD. MODELS SOMEWHAT SCATTERED WITH PLACEMENT
OF THE LOW AT 00Z WED. THE 00Z TUE EURO/GEM/UKMET ESSENTIALLY THE
MIDDLE PATH. THE 00Z TUE GFS IS NOW A FAST OUTLIER...AND THE 00Z
TUE NAM IS A SLIGHTLY SLOW OUTLIER THAN THE MIDDLE PATH MODELS.
AVAILABLE BAROCLINICITY AND RUN-TO-RUN INCREASINGLY ANOMALOUS
UPSTREAM 500MB SHORTWAVE AND -4 STD DEV SFC LOW SUGGEST THE
SLOWER...MORE ROBUST PATH MAY BE MORE REASONABLE TO FOLLOW. THUS
HAVE GONE WITH A BLEND OF THE NAM/EURO/GEM/UKMET. THIS BLEND
PLACES THE LOW IN NW IOWA AT 00Z WED. AT 00Z WED...THE BEST SLUG
OF FORCING WILL LIKELY BE EXITING OUR CWA AND THERE WILL BE THE
ATTENDANT COLD FRONT DROPPING DOWN ALONG OUR WESTERN COUNTIES INTO
MISSOURI.
SVR THREAT...0-6 KM MUCAPE VALUES MARGINAL AT 1000-1200 J/KG. 0-1 KM
HELICITY DECENT AS IT APPROACHES 200 M2/S2. LCL HEIGHTS ARE
SUFFICIENTLY LOW. GIVEN CLIMATOLOGY...STORM MODE MAY EVOLVE TO
LINEAR/BOWING OVERNIGHT. DCAPE VALUES EXCEED 1000 J/KG. NAM PICKING
UP ON PWATS UPWARDS OF 2 INCHES WITH THIS BOUNDARY PASSAGE...SO A
BRIEF HEAVY DOWNPOUR POSSIBLE. ADDITIONALLY...NAM PLACES RIGHT
ENTRANCE REGION OF 100KT JET STREAK IN TARGETED AREA.
HOWEVER...CONFIDENCE NOT THE GREATEST DUE TO LACK OF MODEL
CONSISTENCY AND THE FACT RAIN/CLOUDS THROUGHOUT THE DAY WILL
HINDER DESTABILIZATION. IF STORMS DO GO WITH THE COLD
FRONT...TORNADOES/DAMAGING WINDS LIKELY THE PRIMARY THREATS.
BY 09-12Z WED...BOUNDARY SHOULD BE WELL EAST OF DMX CWA. STRONG
W/NW CAA WILL BE IMMEDIATELY USHERED INTO IOWA AS 850MB TEMPS
SHOULD BE NEAR 8C ON OUR WESTERN CWA EDGE AND 11C ON OUR EASTERN
EDGE. WEDNESDAY AFTERNOON...LOW PROGGD TO DEEPEN TO MID 990MB
RANGE OVER NW WI...WHICH IS VERY ATYPICAL FOR THIS TIME OF YEAR.
GEFS ENSEMBLES SHOW THIS IS NEARING -4 TO -5 STD DEV. PRESSURE
GRADIENT NOT AS TIGHT IN IA AS IT WILL BE IN MN/WESTERN WI.
NONETHELESS...AROUND 3MB/100 KM...DEPENDING ON MODEL PREFERENCE.
FCST SOUNDINGS STILL SHOW AROUND 40 KTS TO THE TOP OF THE MIXED
LAYER. SO AM EXPECTING SFC WINDS IN THE 15 TO 25 MPH RANGE WITH
GUSTS NEARING 35 MPH...ESPECIALLY IN OUR NORTH. PAST SEVERAL MODEL
RUNS HAVE BEEN SUGGESTING ST/SC DECK WITH THE DEFORMATION ZONE
LINGERING ACROSS NORTHERN IA. THUS HAVE KEPT SLIGHT POPS WITH
MINIMAL QPF GOING THROUGH WED EVE. AT THE VERY LEAST...MAX TEMPS
WILL BE HELD DOWN DUE TO THE CLOUD COVER. WENT LOW 60S NORTH...BUT
THIS MAY NEED TO BE KNOCKED DOWN A FEW DEGREES IF ST DECK HOLDS.
THURSDAY INTO SATURDAY...SFC HIGH PRESSURE WILL PASS FROM THE OZARKS
INTO THE OHIO VALLEY REGION. THIS HIGH WILL BE STRONG ENOUGH TO KEEP
DMX CWA DRY THU AND FRI. TEMPS HAVE CERTAINLY TRENDING UPWARDS FOR
FRIDAY AND SATURDAY. THUS HAVE GONE A FEW DEGREES ABOVE GUIDANCE TO
ADD VALUE TO TEMPERATURE FCST.
SINCE LAST FRI...MODELS HAVE BEEN PLACING IA IN RETURN FLOW BY THE
WEEKEND. 00Z TUE LONG RANGE MODELS CONTINUE THIS...KEEPING THE GULF
WIDE OPEN WITH A 35 KT LLJ PRIMED TO TRANSPORT GULF MOISTURE INTO
IOWA. THIS SETUP WILL INCREASE TEMPS BACK INTO THE 80S AND BRING A
RETURN OF POPS FOR THE WEEKEND.
SUNDAY INTO EARLY NEXT WEEK...MODELS IN SURPRISINGLY GREAT
AGREEMENT...PLUS SHOWING RUN-TO-RUN CONSISTENCY GOOD WITH BRINGING A
STRONG SFC HIGH TOWARDS IOWA. AS CONFIDENCE/CONSISTENCY
INCREASING...TEMPS HAVE BEEN TRENDING DOWNWARD WITH CAA EXPECTED
AHEAD OF THIS HIGH. MAY NEED TO LOWER TEMPERATURES EVEN FURTHER IF
THIS SETUP HOLDS.
&&
.AVIATION...18/12Z
ISSUED AT 700 AM CDT MON AUG 17 2015
SHOWERS AND THUNDERSTORMS WILL CONTINUE TO EXPAND ACROSS THE WEST
HALF OF CENTRAL IOWA. LOCALLY HEAVY RAINFALL AND LOW CIGS/VSBYS
WILL BE THE MAIN THREAT THIS MORNING. MID TO LATE AFTN THROUGH MID
EVENING AS A SURFACE LOW SHIFTS INTO MN ADDITIONAL STORMS WILL
DEVELOP ALONG A COLD FRONT. IFR CONDITIONS WILL PERSIST THROUGH 06Z
BEFORE IMPROVING AS THE FRONT PUSHES OUT OF THE TAF LOCATIONS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH THIS EVENING FOR CALHOUN-CARROLL-
CRAWFORD-EMMET-HANCOCK-HUMBOLDT-KOSSUTH-PALO ALTO-POCAHONTAS-SAC-
WEBSTER-WINNEBAGO-WRIGHT.
&&
$$
SHORT TERM...FAB
LONG TERM...KOTENBERG
AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS JACKSON KY
ISSUED BY NATIONAL WEATHER SERVICE WILMINGTON OH
912 AM EDT TUE AUG 18 2015
.UPDATE...
ISSUED AT 905 AM EDT TUE AUG 18 2015
MINOR TWEAKS TO ONGOING FORECAST. SCT-BKN BANDS OF SHOWERS WILL
CONTINUE TO SPREAD NORTHEAST ACROSS ERN KY THROUGH THIS MORNING
INTO EARLY AFTERNOON BEFORE DECREASING SOMEWHAT AS THE AFTN WEARS
ON. STILL A VERY MOIST AIRMASS IN PLACE BUT RAP ANALYSIS AND WATER
VAPOR LOOPS INDICATE THE STRONGEST OF THE SHORTWAVE ENERGY
SHIFTING THROUGH ERN KY AND ERN OHIO MOVING OUT OF THE AREA...SO
WOULD EXPECT ANYTHING THIS AFTERNOON WILL BE LOOSELY FOCUSED AND
TIED MORE DIRECTLY TO POCKETS OF DIABATIC HEATING AND LOCALIZED
CONVERGENCE. THUS HAVE 50-65% RAIN CHANCES THIS MORNING DWINDLING
BACK TO 15-25% BY MID-LATE AFTN. WE MAY BE A BIT OPTIMISTIC THAT
TEMPS WILL MAKE THE LOWER 80S IN THE LOWLANDS THIS AFTN...CURRENT
VIS LOOPS INDICATE QUITE A BIT OF CLOUDS OVER THE AREA AND
UPSTREAM...SO WILL WATCH THIS FOR THE POTENTIAL NEED OF DROPPING
BACK A COUPLE OF DEGREES FOR THESE HIGHS. PULLED FOG OUT OF THE
FORECAST AS VSBYS HAVE IMPROVED SOMEWHAT OVER EARLIER VALUES.
UPDATE ISSUED AT 655 AM EDT TUE AUG 18 2015
JUST SENT OUT AN UPDATED VERSION OF THE ZONE FORECAST TEXT
PRODUCT THAT THE WILMINGTON WEATHER OFFICE HAD TO ISSUE FOR US
EARLIER THIS MORNING. A MAJOR COMMS OUTAGE OVERNIGHT KEPT US FROM
BEING ABLE TO ISSUE ANY OF OUR OWN PRODUCTS BETWEEN 1 AND 6 AM.
THE NEW FORECAST UPDATE WILL REFLECT INCREASING COVERAGE OF
SHOWERS AND STORMS THIS MORNING AS SOME ENERGY AND MOISTURE FROM
THE GULF OF MEXICO MAKE THEIR WAY INTO THE FORECAST AREA. THE NEW
FORECAST WILL CONTINUE TO MENTION EARLY MORNING FOG AND WILL NEED
TO BE UPDATED AGAIN AROUND 9 AM.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 508 AM EDT TUE AUG 18 2015
FAIRLY WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS ARE
PERSISTING THIS MORNING ACROSS FAR EASTERN KENTUCKY WITH ISOLATED
TO SCATTERED LIGHT SHOWERS ELSEWHERE ACROSS THE AREA. THIS IS ALL
ASSOCIATED WITH A WEAKENING MID LEVEL SHORT WAVE THAT IS FORECAST
TO CONTINUE TO SHIFT OFF TO THE EAST THROUGH THE MORNING HOURS.
THIS SHOULD LEAD TO A DECREASING TREND IN COVERAGE THROUGH THE
FIRST PART OF THE DAY. HOWEVER...IN A CONTINUED SOUTHWESTERLY
MID/UPPER LEVEL FLOW PATTERN...SEVERAL WEAK VORTS WILL LIFT EAST
NORTHEAST ACROSS THE TENNESSEE VALLEY LATER TODAY AND INTO
TONIGHT. THIS WILL RESULT IN SOME LINGERING CHANCES FOR
PRECIPITATION INTO TONIGHT...ESPECIALLY ACROSS FAR SOUTHEAST
PORTIONS OF KENTUCKY. HIGHS TODAY WILL RANGE FROM THE UPPER 70S
ALONG THE VIRGINIA/KENTUCKY BORDER TO THE LOWER 80S ELSEWHERE
ACROSS THE AREA. LOWS TONIGHT WILL GENERALLY BE IN THE UPPER 60S.
A STRENGTHENING LOW PRESSURE SYSTEM WILL MOVE INTO THE WESTERN
GREAT LAKES WEDNESDAY INTO THURSDAY ALLOWING FOR THE UPPER LEVEL
TROUGH OVER THE MISSISSIPPI VALLEY TO PIVOT EASTWARD INTO THE
UPPER OHIO VALLEY. THIS WILL HELP DRIVE A COLD FRONT THROUGH THE
REGION LATE WEDNESDAY NIGHT AND INTO THURSDAY. AHEAD OF
THIS...EXPECT AN INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS
WEDNESDAY AFTERNOON INTO WEDNESDAY NIGHT. PCPN SHOULD THEN BEGIN
TO TAPER OFF FROM THE WEST THROUGH THE DAY ON THURSDAY AS SOME
DRIER AIR WORKS IN BEHIND THE FRONT. EXPECT HIGHS ON WEDNESDAY IN
THE LOW TO MID 80S...COOLING OFF TO THE UPPER 70S TO LOWER 80S
FOR THURSDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 508 AM EDT TUE AUG 18 2015
SURFACE HIGH PRESSURE WILL BUILD INTO THE REGION FRIDAY INTO
SATURDAY. THIS WILL RESULT IN DRY CONDITIONS WITH HIGHS IN THE
UPPER 70S TO LOWER 80S FOR FRIDAY...WARMING INTO THE LOW TO MID
80S FOR SATURDAY.
MID LEVEL SHORT WAVE ENERGY WILL MOVE ACROSS THE NORTHERN PLAINS
AND INTO THE GREAT LAKES REGION SUNDAY INTO MONDAY. THIS WILL
HELP DRIVE AN ASSOCIATED COLD FRONT ACROSS THE APPALACHIANS LATE
SUNDAY NIGHT. INCREASING MOISTURE AHEAD OF THE FRONT WILL LEAD TO
A CHANCE OF SHOWERS AND THUNDERSTORMS PRIMARILY LATER SUNDAY
AFTERNOON AND INTO SUNDAY NIGHT. DRIER AIR WILL THEN FILTER IN
BEHIND THE FRONT FOR MONDAY. EXPECT HIGHS IN THE MID TO POSSIBLY
UPPER 80S ON SUNDAY AND THEN MAINLY THE LOWER 80S FOR MONDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 655 AM EDT TUE AUG 18 2015
THE 12Z TAFS WILL BEGIN BY ADDRESSING FOG AT JKL...LOZ...AND SYM
EARLY THIS MORNING. ANY REMAINING FOG SHOULD BE PRETTY MUCH GONE
BY 9 AM. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL BE
MOVING INTO THE AREA EARLY THIS MORNING...AND WILL BE INCREASING
IN COVERAGE THROUGH OUT THE MORNING. THE TAF SITES COULD
EXPERIENCE MVFR CONDITIONS AS A SHOWER OR STORM MOVES PAST. THE
RAIN IS EXPECTED TO TAPER OFF QUICKLY AFTER 2 OR 3Z TONIGHT.
EXTENSIVE CLOUD COVER AND PERSISTENT LIGHT WINDS SHOULD KEEP FOG
FORMATION AT A MINIMUM OVERNIGHT INTO EARLY WEDNESDAY MORNING.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...BINAU /WFO ILN/
SHORT TERM...AR
LONG TERM...HAL
AVIATION...AR
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1033 AM EDT TUE AUG 18 2015
.UPDATE...
ISSUED AT 1033 AM EDT TUE AUG 18 2015
SCT/NMRS SHOWERS CONTINUE TO DEVELOP ACROSS MUCH OF THE WRN GREAT
LAKES LATE THIS MORNING...INCLUDING OUR CWA WHERE SOME BRIEF ISOLD
THUNDER HAS ALSO DEVELOPED PER RECENT LIGHTNING DATA. FORCING
REMAINS WEAK...WITH LITTLE IN THE WAY TO ORGANIZE ANY OF THE
CONVECTION. WARM FRONT IS TRYING TO PUSH NORTHWARD INTO SRN
SECTIONS OF OUR CWA...BUT IS MAKING LITTLE PROGRESS GIVEN THICK
CLOUD COVER AND PRECIP ACROSS OUR AREA. CLOUDS AND PRECIP ARE ALSO
GREATLY LIMITING THE POTENTIAL FOR INCREASED INSTABILITY AS THE
DAY SLOWLY HEATS UP. ALL OF THE ABOVE WILL REMAIN IN PLACE THRU
THE AFTERNOON...WHICH WILL CONTINUE TO LIMIT OUR THUNDER CHANCES.
HOWEVER...DO STILL EXPECT PRECIP ITSELF WILL GRADUALLY EXPAND
THANKS TO SOME DIURNALLY-ENHANCED INSTABILITY AND AMPLE MOISTURE
POOLING ALONG AND NORTH OF THE WARM FRONT. HAVE MADE ONLY MINOR
ADJUSTMENTS TO WX/POP FORECAST FOR THE AFTERNOON. OVERALL...EXPECT
A MAINLY CLOUDY AFTERNOON WITH WAVES OF SHOWERS AND POSSIBLY A FEW
THUNDERSTORMS...WITH THE HIGHEST POPS ACROSS NRN LWR MICHIGAN.
&&
.NEAR TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 328 AM EDT TUE AUG 18 2015
HIGH IMPACT WEATHER POTENTIAL...NON-SEVERE THUNDERSTORMS TODAY AND
TONIGHT.
DIFFUSE COLD FRONT RESTS ROUGHLY FROM OSC TO MBL. THIS FRONT IS
STALLING OUT...AS LEE CYCLOGENESIS GETS UNDERWAY IN THE CENTRAL
HIGH PLAINS. SOME SHRA ARE SEEN OVER CENTRAL/NORTHERN LAKE MI AND
SURROUNDING AREAS. A FEW SHRA HAVE ALSO RECENTLY DEVELOPED JUST SW
OF LAN. NO THUNDER LEFT IN OUR NECK OF THE WOODS. THE FRONT WILL
WOBBLE ACROSS CENTRAL/NORTHERN LOWER MI OVER THE NEXT 24
HOURS...AS HEATING/CONVECTION/SOUTHERLY FLOW WAXES AND WANES.
PRECIP TRENDS ARE THE MAIN CONCERN.
TODAY...A POTENT SHORTWAVE WILL DIG FROM THE NORTHERN TO CENTRAL
HIGH PLAINS TODAY. IN RESPONSE...PRESSURES WILL RAPIDLY FALL IN THE
CENTRAL PLAINS. BY MID-EVENING...A SUB-1000MB LOW WILL BE MOVING
INTO NW IOWA. SOUTHERLY 1000-850MB FLOW INTO LOWER MI WILL INCREASE
TO SOME DEGREE...THOUGH THE TIGHTEST PRESSURE GRADIENT WILL REMAIN
TO OUR WEST THRU 00Z. STILL...THAT AND DIURNAL HEATING/MIXING WILL
TEND TO PUSH THE FRONT NORTH. HOWEVER...PRECIP AND SUBSEQUENT COLD-
POOL GENERATION NORTH OF THE FRONT WILL WORK TO SUPPRESS ANY
NORTHWARD MOVEMENT. THE NAM WANTS TO PUSH THE FRONT QUICKLY NORTH IN
THE 1ST HALF OF THE DAY...AN INTERNALLY INCONSISTENT APPROACH SINCE
IT IS ALSO AMONG THE WETTEST SOLUTIONS NORTH OF THE FRONT THIS
MORNING. THE RAP OFFERS A BETTER ALTERNATIVE IN THE NEAR-TERM...WITH
THE FRONT REACHING A MANTON-HARRISVILLE LINE BY MIDDAY...BEFORE
GETTING ABRUPTLY SHOVED SOUTHWARD AGAIN AS PRECIP BECOMES MORE
EXPANSIVE.
SPEAKING OF WHICH...THERE ARE A PAIR OF SHORTWAVES MOVING EAST
TOWARD THE LAKES REGION EARLY THIS MORNING...ONE IN W CENTRAL WI AND
THE 2ND IN NW IL. THESE WILL BOTH ACT TO PROVIDE FORCING FOR ASCENT
JUST AFTER SUNRISE IN WESTERN SECTIONS. HOWEVER...AT THIS TIME OF
DAY NEITHER HAS MUCH IN THE WAY OF INSTABILITY TO WORK WITH. NOTE
THAT ACTIVITY MOVING ENE OUT OF CHICAGO IS FIZZLING RAPIDLY OVER
SOUTHERN LAKE MI. GENERALLY THINK THAT...THRU 10AM...THE MAIN PRECIP
CHANCES WILL BE WEST OF TVC/CAD...IN EASTERN UPPER MI...AND IN
PARTS OF NE LOWER (IF DOWNSTATE ACTIVITY DEVELOPS NE-WARD AS
AGGRESSIVELY AS RECENT RAP RUNS SUGGEST).
HOWEVER...WE HAVE PLENTY OF MOISTURE (PWATS 1.5-1.7) AND SOME
FORCING FOR ASCENT AVAILABLE. SO IT WILL TAKE VERY LITTLE HEATING
(EVEN WITH CONSIDERABLE CLOUD COVER) TO PRIME THE AIRMASS FOR
CONVECTION. THIS IS ESPECIALLY THE CASE GIVEN THAT (AS OPPOSED TO
YESTERDAY) WE ACTUALLY HAVE CROSS-FRONTAL 1000-850MB FLOW.
ANTICIPATE SHRA WILL RAPIDLY EXPAND IN COVERAGE OVER NW LOWER MI
BETWEEN 10AM AND NOON. FURTHER EXPANSION ACROSS THE BULK OF NORTHERN
LOWER WILL OCCUR AS ACTIVITY CONTINUES TO PERCOLATE THRU THE
AFTERNOON. SOME OF THIS ACTIVITY WILL LEAK INTO EASTERN UPPER...BUT
THAT FAR NORTH OF THE WARM FRONT SUSPECT COVERAGE THERE WILL BE LESS
THAN THE NAM/GFS ARGUE. CONVECTION WILL BE QUICK TO TRIGGER...SO WE
WON/T REALLY GET THE CHANCE TO BUILD UP MUCH IN THE WAY OF CAPE.
MLCAPES SHOULD STAY LESS THAN 500J/KG. THIS WILL KEEP PRECIP MAINLY
AS SHRA...WITH A FEW EMBEDDED TSRA...AND NO SVR THREAT. LOCALIZED
RAINFALL AMOUNTS OF A QUARTER TO HALF AN INCH WILL BE SEEN.
WILL BE A MUGGY DAY...BUT TEMPS WILL BE SHARPLY LIMITED BY
CLOUDS/PRECIP. HIGHS WILL BE MAINLY IN THE 70S...PEAKING UP CLOSE TO
80F IN A FEW SPOTS.
TONIGHT...PRIMARY 500MB CIRCULATION CLOSES OFF AND DEEPENS AS IT
MOVES FROM EASTERN SD TO SOUTHERN MN. THE CORRESPONDING SURFACE LOW
WILL DEEPEN TO 994MB AS IT MOVES TO THE MN/WI BORDER. IN ADVANCE OF
THIS DEVELOPING CYCLONE...SOUTHERLY 850MB WINDS WILL INCREASE TO 20-
30KT. THIS WILL PUSH THE SURFACE WARM FRONT MORE EMPHATICALLY
NORTHWARD TOWARD FAR NORTHERN LOWER OR THE STRAITS REGION. CHANCES
FOR PRECIP WILL DECREASE BEHIND THE FRONT. SHRA COVERAGE WILL BE
CONSIDERABLE ACROSS THE FORECAST AREA IN THE EVENING...BUT POPS WILL
DECREASE (THOUGH NOT DISAPPEAR) SOUTH OF M-32 OVERNIGHT. IN
ADDITION...IT IS LIKELY OVERNIGHT THAT ONE OR MORE MCS/S WILL BE
MOVING EAST IN THE WARM SECTOR INTO THE SW LAKES REGION. DON/T THINK
THAT THESE WILL HOLD TOGETHER AND REACH SW SECTIONS TOWARD
DAYBREAK...BUT IT/S NOT IMPOSSIBLE. THAT/S OUR VERY LOW-END SHOT AT
ANYTHING SVR...OTHERWISE MLCAPE IS TOO LIMITED.
STILL MUGGY AND A VERY WARM NIGHT...WITH LOWS IN THE MID 60S TO
AROUND 70F.
&&
.SHORT TERM...(WEDNESDAY THROUGH THURSDAY NIGHT)
ISSUED AT 328 AM EDT TUE AUG 18 2015
LOW PRESSURE EMERGES OUT OF THE CENTRAL PLAINS TODAY THEN HEADS
NORTHEAST INTO THE NORTHERN MISSISSIPPI VALLEY WHILE DEEPENING. THE
IMPACTS FROM THIS SYSTEM WILL BE THE FOCUS OF THE FORECAST WITH THE
MAIN CHALLENGE BEING THE POTENTIAL FOR SEVERE STORMS WEDNESDAY.
WEDNESDAY...THE TRACK OF A NEGATIVELY TILTED TROUGH AND ASSOCIATED
AREA OF DEEPENING LOW PRESSURE TO OUR NORTHWEST IS EXPECTED TO LEAD
TO A SOLID AREA OF SHOWERS ACROSS EASTERN UPPER AND FAR NORTHWEST
LOWER WEDNESDAY WITH SLIGHTLY LESSER BUT MORE CONVECTIVE
SHOWER/STORM COVERAGE ACROSS SOUTHEAST ZONES. THERE IS A THREAT FOR
SEVERE STORMS...MAINLY BECAUSE OF STRONGER WINDS ALOFT (NAM 0-6KM
BULK SHEAR 30 TO 40 KNOTS WITH THE MORE BULLISH GFS A ROBUST 50 TO
55 KNOTS!). IN ADDITION TO THE STRONG WINDS ALOFT NORTHEAST LOWER
MAY ALSO GET INTO HEALTHY AMOUNTS OF INSTABILITY IF THE SUN IS ABLE
TO BREAK OUT IN THE DRY SLOT. SO NOT SURPRISINGLY...SPC HAS JUST
PLACED ALL OF NORTHERN LOWER IN A SLIGHT RISK FOR WIND AND/OR HAIL.
MODELS CONTINUE TO DIFFER ON THE FINER DETAILS OF THIS SYSTEM
INCLUDING TIMING AND STRENGTH (THOUGH BOTH THE ECMWF AND GFS ARE
TRENDING STRONGER) SO STAY TUNED FOR FURTHER UPDATES AS THIS
POSSIBLE EVENT GETS A LITTLE CLOSER. A SYSTEM THIS DEEP THIS TIME OF
THE YEAR IS A BIT UNUSUAL SO THINGS HAVE THE POTENTIAL TO GET
INTERESTING. HIGHS RANGING FROM THE MUGGY UPPER 70S NORTH TO PERHAPS
THE TOASTY UPPER 80S SOUTHEAST ZONES.
WEDNESDAY NIGHT...A FEW MORE SHOWERS (AND THUNDERSTORMS EAST) ARE
LIKELY AS THE COLD FRONT ASSOCIATED WITH THE LOW PRESSURE SYSTEM
MOVES ACROSS THE REGION (ACTUALLY IT MAY BE MORE OF AN OCCLUDED
FRONT AT THAT POINT). LOWS RANGING FROM THE UPPER 50S TO MIDDLE 60S.
THURSDAY...WRAP AROUND SHOWERS ARE POSSIBLE ACROSS EASTERN UPPER AND
FAR NORTHERN LOWER...ESPECIALLY IN THE MORNING. COOLER WITH HIGHS
ONLY IN THE UPPER 60S AND LOWER 70S.
&&
.LONG TERM...(FRIDAY THROUGH MONDAY)
ISSUED AT 328 AM EDT TUE AUG 18 2015
HIGH PRESSURE BUILDS IN FRIDAY WHICH SHOULD HOLD ON THROUGH SATURDAY
NIGHT YIELDING WARMER AND DRIER CONDITIONS. ANOTHER AREA OF LOW
PRESSURE TRACKING BY TO OUR NORTHWEST WILL THEN BRING MORE CHANCES
FOR SHOWERS AND THUNDERSTORMS SUNDAY...WITH WRAP AROUND DRIVEN
SHOWERS POSSIBLY LINGERING INTO MONDAY (MODELS ARE NOT IN AGREEMENT
HERE BUT PLENTY OF TIME TO MAKE ADJUSTMENTS). HIGHS BACK IN THE
UPPER 70S AND LOWER 80S FRIDAY THROUGH SUNDAY. COOLER AGAIN FOR
MONDAY WITH HIGHS IN THE UPPER 60S AND LOWER 70S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 655 AM EDT TUE AUG 18 2015
SOME IMPROVEMENT IN FLYING CONDITIONS TODAY. BRIEF VSBY POSSIBLE
AT JUST ABOUT ANY TIME IN SHRA.
STALLED COLD FRONT IS LAID OUT ACROSS CENTRAL LOWER MI. THIS
FRONT WILL WOBBLE ACROSS CENTRAL AND NORTHERN LOWER MI TODAY AND
TONIGHT. CONSIDERABLE SHRA AND A FEW TSRA WILL BE SEEN NORTH OF
THE FRONT...ESPECIALLY FROM LATE MORNING TODAY THRU TONIGHT. BRIEF
VSBY RESTRICTIONS WILL BE POSSIBLE. APN IS CURRENTLY IFR...OTHER
SITES VFR. APN WILL SEE IMPROVEMENT AS THE DAY PROCEEDS.
WINDS WILL BE LIGHT SOUTHERLY TO EASTERLY.
&&
.MARINE...
ISSUED AT 328 AM EDT TUE AUG 18 2015
A STALLED FRONT WILL WOBBLE ACROSS CENTRAL LOWER MI TODAY...BEFORE
MOVING NORTH TONIGHT AS A WARM FRONT. SE-ERLY WINDS WILL BE LIGHT
THRU THIS EVENING...BUT INCREASE OVERNIGHT. SMALL CRAFT
ADVISORIES WILL LIKELY BE NEEDED ON SOME WATERS BY WEDNESDAY
AFTERNOON. A STRONG COLD FRONT WILL CROSS THE REGION LATE
WEDNESDAY...WITH STRONG TO POTENTIALLY SVR THUNDERSTORMS.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...MLR
NEAR TERM...JAZ
SHORT TERM...SULLIVAN
LONG TERM...SULLIVAN
AVIATION...JAZ
MARINE...JAZ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
745 AM EDT TUE AUG 18 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM EDT TUE AUG 18 2015
WV IMAGERY AND RAP ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
FROM NRN HUDSON BAY INTO THE NRN PLAINS RESULTING IN WNW FLOW
THROUGH THE NRN GREAT LAKES. A WEAK SHORTWAVE TROUGH AND AREA OF 850-
700 MB FGEN SUPPORTED A BAND OF SHOWERS OVER WRN UPPER MI. UPSTREAM
A VIGOROUS SHRTWV WAS MOVING THROUGH SD/NE. AT THE SFC...A WEAK
FRONTAL BOUNDARY EXTENDED FROM CNTRL LOWER MI THROUGH SE WI AND SW
IA TO LOW PRES OVER NRN KS. WITH HIGH PRES OVER NRN ONTARIO...LIGHT
NE WINDS PREVAILED ACROSS THE NRN LAKES.
EXPECT THE PCPN OVER THE WEST TO DIMINISH EARLY AS THE SHRTWV AND
FGEN LIFT MOVE OFF TO THE NORTHEAST. HOWEVER...SOME SCT -SHRA MAY
LINGER OVER THE SOUTH AS ANOTHER WEAK SHRTWV BRUSHES THE AREA TO THE
SE.
ATTENTION...WILL THEN TURN TO THE DEVELOPING AND UNSEASONABLY STRONG
LOW PRES SYSTEM MOVING OUT OF THE PLAINS. THE SD/NE SHRTWV WILL
SUPPORT A DEEPENING LOW MOVING INTO THE NW CORNER OF IA BY 00Z/WED
AND ERN MN BY 12Z/WED. THE MODELS HAVE TRENDED TOWARD A SLIGHTLY
SLOWER PROGRESSION OF THE LOW AS THE STRONG JET MOVING OUT OF THE
PLAINS HELPS CUT OFF THE MID LEVEL LOW. AN AREA OF STRONG MOISTURE
TRANSPORT AND 305K-310K ISENTROPIC ASCENT WILL BRING AN AREA OF RAIN
THROUGH UPPER MI TONIGHT...MAINLY AFTER MIDNIGHT. HOWEVER...THIS
TRANSIENT BAND IS EXPECTED TO BRING QPF AMOUNTS ONLY IN THE 0.25-
0.50 INCH RANGE OVER THE CNTRL AND ERN CWA. HIGHER AMOUNTS TO AROUND
AN INCH WILL BE POSSIBLE OVER THE FAR WEST CLOSER TO THE STRONGEST
DEEP LAYER QVECTOR CONV AND LIFT WHICH WILL REMAIN TO THE WEST OVER
NRN MN AND WRN LAKE SUPERIOR. WITH MODEST MUCAPE VALUES INTO THE 200-
400 J/KG RANGE ONLY ISOLD TSRA ARE EXPECTED.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 339 AM EDT TUE AUG 18 2015
BY 12Z WED AN INTENSIFYING LOW WILL BE APPROACHING OR OVER THE WRN
CWA. THE 00Z/18 GFS HAS COME INTO GOOD AGREEMENT WITH THE 12Z/17
ECMWF IN DEEPENING THE SFC LOW TO 993-995MB AS THE SYSTEM CLOSES OFF
OVER WRN LAKE SUPERIOR WED. THE NAM . BY 12Z THU THE LOW WILL BE
OCCLUDED N OF LAKE SUPERIOR AND WILL QUICKLY SHUNT N TO HUDSON BAY
BY 00Z FRI.
OVERALL EXPECTATIONS HAVE NOT CHANGED MUCH FROM THE DAY SHIFT MON. A
SURGE OF PRECIP WILL BE EXITING N WED MORNING AHEAD OF THE COLD
FRONT AND THEN DRY SLOT THAT WILL MOVE IN FROM THE SW WED LATE
MORNING/AFTERNOON. COULD SEE SOME STRONG TO POSSIBLY SEVERE STORMS
ALONG THE COLD FRONT AS EFFECTIVE SHEAR IS ENHANCED...BUT OTHERWISE
NOT EXPECTING SEVERE STORMS. AFTER THE DRY SLOT MOVES INTO MAINLY
THE CENTRAL AND ERN CWA...WRAP AROUND PRECIP/MOISTURE WILL MOVE INTO
WRN UPPER MI. THE WRAP AROUND PRECIP WILL SPREAD TO NRN AND WRN
UPPER MI WED NIGHT AND CONTINUE THROUGH MOST OF THU. WED LOOKS WINDY
WITH S-SW WINDS GUSTING TO 25-35 MPH. WINDS THU WILL BE SIMILAR
STRENGTH OF WED...BUT OUT OF THE W.
FRI AND SAT LOOK DRY WITH SW FLOW ALONG AND A SFC HIGH OVER MUCH OF
THE ERN CONUS. HOWEVER...MODELS CONTINUE TO INDICATE THAT ANOTHER
STORM SYSTEM COULD BRING PRECIP SUN INTO MON...BUT DETAILS REMAIN
UNCLEAR AT THIS TIME.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 742 AM EDT TUE AUG 18 2015
MAINLY MVFR CIGS ARE EXPECTED AT SAW WITH CONTINUED MOIST UPSLOPE NE
FLOW TODAY. CIGS SHOULD ALSO LOWER AT IWD AND CMX BUT WITH DRIER AIR
IN PLACE...EXPECT CONDITIONS TO REMAIN VFR UNTIL LATER THIS
AFTERNOON. A STRENGTHENING ESE FLOW AHEAD OF DEEPENING LO PRES IN
THE PLAINS WL BRING A RETURN OF MORE WDSPRD -RA/MVFR CONDITIONS IN
THE EVENING DROPPING TO IFR OVERNIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 514 AM EDT TUE AUG 18 2015
HIGH PRES STRETCHING FROM SOUTHERN MANITOBA THROUGH JAMES BAY WILL
EXTEND A RIDGE INTO THE UPPER LAKES THROUGH THIS MORNING...RESULTING
IN LIGHT WINDS UNDER 15KT ACROSS LAKE SUPERIOR. THEN...AS LOW PRES
ORGANIZES AND STRENGTHENS OVER THE PLAINS TUE...NE WINDS WILL BEGIN
TO INCREASE...ESPECIALLY OVER WRN LAKE SUPERIOR WHERE GUSTS SHOULD
REACH 25-30KT LATE AFTN/EARLY EVENING. THIS LOW WILL BECOME
UNSEASONABLY DEEP FOR AUG AS IT LIFTS ACROSS FAR WRN LAKE SUPERIOR
WED AFTERNOON. 20-30KT WINDS ARE EXPECTED OVER MUCH OF THE LAKE
TONIGHT INTO WED. MAY SEE GALE FORCE GUSTS OVER FAR WRN LAKE SUPERIOR
IN THE NE WINDS AHEAD OF THE LOW TONIGHT AND THEN IN THE WESTERLY
WINDS ACROSS MAINLY CENTRAL LAKE SUPERIOR ON THU AS THE LOW LIFTS N
OF THE AREA. WINDS WILL DIMINISH TO UNDER 20KT FRI...AND THEN BEGIN
TO INCREASE AGAIN ON SAT AHEAD OF THE NEXT COLD FRONT MOVING OUT
ACROSS THE PLAINS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GAYLORD MI
654 AM EDT TUE AUG 18 2015
.NEAR TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 328 AM EDT TUE AUG 18 2015
HIGH IMPACT WEATHER POTENTIAL...NON-SEVERE THUNDERSTORMS TODAY AND
TONIGHT.
DIFFUSE COLD FRONT RESTS ROUGHLY FROM OSC TO MBL. THIS FRONT IS
STALLING OUT...AS LEE CYCLOGENESIS GETS UNDERWAY IN THE CENTRAL
HIGH PLAINS. SOME SHRA ARE SEEN OVER CENTRAL/NORTHERN LAKE MI AND
SURROUNDING AREAS. A FEW SHRA HAVE ALSO RECENTLY DEVELOPED JUST SW
OF LAN. NO THUNDER LEFT IN OUR NECK OF THE WOODS. THE FRONT WILL
WOBBLE ACROSS CENTRAL/NORTHERN LOWER MI OVER THE NEXT 24
HOURS...AS HEATING/CONVECTION/SOUTHERLY FLOW WAXES AND WANES.
PRECIP TRENDS ARE THE MAIN CONCERN.
TODAY...A POTENT SHORTWAVE WILL DIG FROM THE NORTHERN TO CENTRAL
HIGH PLAINS TODAY. IN RESPONSE...PRESSURES WILL RAPIDLY FALL IN THE
CENTRAL PLAINS. BY MID-EVENING...A SUB-1000MB LOW WILL BE MOVING
INTO NW IOWA. SOUTHERLY 1000-850MB FLOW INTO LOWER MI WILL INCREASE
TO SOME DEGREE...THOUGH THE TIGHTEST PRESSURE GRADIENT WILL REMAIN
TO OUR WEST THRU 00Z. STILL...THAT AND DIURNAL HEATING/MIXING WILL
TEND TO PUSH THE FRONT NORTH. HOWEVER...PRECIP AND SUBSEQUENT COLD-
POOL GENERATION NORTH OF THE FRONT WILL WORK TO SUPPRESS ANY
NORTHWARD MOVEMENT. THE NAM WANTS TO PUSH THE FRONT QUICKLY NORTH IN
THE 1ST HALF OF THE DAY...AN INTERNALLY INCONSISTENT APPROACH SINCE
IT IS ALSO AMONG THE WETTEST SOLUTIONS NORTH OF THE FRONT THIS
MORNING. THE RAP OFFERS A BETTER ALTERNATIVE IN THE NEAR-TERM...WITH
THE FRONT REACHING A MANTON-HARRISVILLE LINE BY MIDDAY...BEFORE
GETTING ABRUPTLY SHOVED SOUTHWARD AGAIN AS PRECIP BECOMES MORE
EXPANSIVE.
SPEAKING OF WHICH...THERE ARE A PAIR OF SHORTWAVES MOVING EAST
TOWARD THE LAKES REGION EARLY THIS MORNING...ONE IN W CENTRAL WI AND
THE 2ND IN NW IL. THESE WILL BOTH ACT TO PROVIDE FORCING FOR ASCENT
JUST AFTER SUNRISE IN WESTERN SECTIONS. HOWEVER...AT THIS TIME OF
DAY NEITHER HAS MUCH IN THE WAY OF INSTABILITY TO WORK WITH. NOTE
THAT ACTIVITY MOVING ENE OUT OF CHICAGO IS FIZZLING RAPIDLY OVER
SOUTHERN LAKE MI. GENERALLY THINK THAT...THRU 10AM...THE MAIN PRECIP
CHANCES WILL BE WEST OF TVC/CAD...IN EASTERN UPPER MI...AND IN
PARTS OF NE LOWER (IF DOWNSTATE ACTIVITY DEVELOPS NE-WARD AS
AGGRESSIVELY AS RECENT RAP RUNS SUGGEST).
HOWEVER...WE HAVE PLENTY OF MOISTURE (PWATS 1.5-1.7) AND SOME
FORCING FOR ASCENT AVAILABLE. SO IT WILL TAKE VERY LITTLE HEATING
(EVEN WITH CONSIDERABLE CLOUD COVER) TO PRIME THE AIRMASS FOR
CONVECTION. THIS IS ESPECIALLY THE CASE GIVEN THAT (AS OPPOSED TO
YESTERDAY) WE ACTUALLY HAVE CROSS-FRONTAL 1000-850MB FLOW.
ANTICIPATE SHRA WILL RAPIDLY EXPAND IN COVERAGE OVER NW LOWER MI
BETWEEN 10AM AND NOON. FURTHER EXPANSION ACROSS THE BULK OF NORTHERN
LOWER WILL OCCUR AS ACTIVITY CONTINUES TO PERCOLATE THRU THE
AFTERNOON. SOME OF THIS ACTIVITY WILL LEAK INTO EASTERN UPPER...BUT
THAT FAR NORTH OF THE WARM FRONT SUSPECT COVERAGE THERE WILL BE LESS
THAN THE NAM/GFS ARGUE. CONVECTION WILL BE QUICK TO TRIGGER...SO WE
WON/T REALLY GET THE CHANCE TO BUILD UP MUCH IN THE WAY OF CAPE.
MLCAPES SHOULD STAY LESS THAN 500J/KG. THIS WILL KEEP PRECIP MAINLY
AS SHRA...WITH A FEW EMBEDDED TSRA...AND NO SVR THREAT. LOCALIZED
RAINFALL AMOUNTS OF A QUARTER TO HALF AN INCH WILL BE SEEN.
WILL BE A MUGGY DAY...BUT TEMPS WILL BE SHARPLY LIMITED BY
CLOUDS/PRECIP. HIGHS WILL BE MAINLY IN THE 70S...PEAKING UP CLOSE TO
80F IN A FEW SPOTS.
TONIGHT...PRIMARY 500MB CIRCULATION CLOSES OFF AND DEEPENS AS IT
MOVES FROM EASTERN SD TO SOUTHERN MN. THE CORRESPONDING SURFACE LOW
WILL DEEPEN TO 994MB AS IT MOVES TO THE MN/WI BORDER. IN ADVANCE OF
THIS DEVELOPING CYCLONE...SOUTHERLY 850MB WINDS WILL INCREASE TO 20-
30KT. THIS WILL PUSH THE SURFACE WARM FRONT MORE EMPHATICALLY
NORTHWARD TOWARD FAR NORTHERN LOWER OR THE STRAITS REGION. CHANCES
FOR PRECIP WILL DECREASE BEHIND THE FRONT. SHRA COVERAGE WILL BE
CONSIDERABLE ACROSS THE FORECAST AREA IN THE EVENING...BUT POPS WILL
DECREASE (THOUGH NOT DISAPPEAR) SOUTH OF M-32 OVERNIGHT. IN
ADDITION...IT IS LIKELY OVERNIGHT THAT ONE OR MORE MCS/S WILL BE
MOVING EAST IN THE WARM SECTOR INTO THE SW LAKES REGION. DON/T THINK
THAT THESE WILL HOLD TOGETHER AND REACH SW SECTIONS TOWARD
DAYBREAK...BUT IT/S NOT IMPOSSIBLE. THAT/S OUR VERY LOW-END SHOT AT
ANYTHING SVR...OTHERWISE MLCAPE IS TOO LIMITED.
STILL MUGGY AND A VERY WARM NIGHT...WITH LOWS IN THE MID 60S TO
AROUND 70F.
&&
.SHORT TERM...(WEDNESDAY THROUGH THURSDAY NIGHT)
ISSUED AT 328 AM EDT TUE AUG 18 2015
LOW PRESSURE EMERGES OUT OF THE CENTRAL PLAINS TODAY THEN HEADS
NORTHEAST INTO THE NORTHERN MISSISSIPPI VALLEY WHILE DEEPENING. THE
IMPACTS FROM THIS SYSTEM WILL BE THE FOCUS OF THE FORECAST WITH THE
MAIN CHALLENGE BEING THE POTENTIAL FOR SEVERE STORMS WEDNESDAY.
WEDNESDAY...THE TRACK OF A NEGATIVELY TILTED TROUGH AND ASSOCIATED
AREA OF DEEPENING LOW PRESSURE TO OUR NORTHWEST IS EXPECTED TO LEAD
TO A SOLID AREA OF SHOWERS ACROSS EASTERN UPPER AND FAR NORTHWEST
LOWER WEDNESDAY WITH SLIGHTLY LESSER BUT MORE CONVECTIVE
SHOWER/STORM COVERAGE ACROSS SOUTHEAST ZONES. THERE IS A THREAT FOR
SEVERE STORMS...MAINLY BECAUSE OF STRONGER WINDS ALOFT (NAM 0-6KM
BULK SHEAR 30 TO 40 KNOTS WITH THE MORE BULLISH GFS A ROBUST 50 TO
55 KNOTS!). IN ADDITION TO THE STRONG WINDS ALOFT NORTHEAST LOWER
MAY ALSO GET INTO HEALTHY AMOUNTS OF INSTABILITY IF THE SUN IS ABLE
TO BREAK OUT IN THE DRY SLOT. SO NOT SURPRISINGLY...SPC HAS JUST
PLACED ALL OF NORTHERN LOWER IN A SLIGHT RISK FOR WIND AND/OR HAIL.
MODELS CONTINUE TO DIFFER ON THE FINER DETAILS OF THIS SYSTEM
INCLUDING TIMING AND STRENGTH (THOUGH BOTH THE ECMWF AND GFS ARE
TRENDING STRONGER) SO STAY TUNED FOR FURTHER UPDATES AS THIS
POSSIBLE EVENT GETS A LITTLE CLOSER. A SYSTEM THIS DEEP THIS TIME OF
THE YEAR IS A BIT UNUSUAL SO THINGS HAVE THE POTENTIAL TO GET
INTERESTING. HIGHS RANGING FROM THE MUGGY UPPER 70S NORTH TO PERHAPS
THE TOASTY UPPER 80S SOUTHEAST ZONES.
WEDNESDAY NIGHT...A FEW MORE SHOWERS (AND THUNDERSTORMS EAST) ARE
LIKELY AS THE COLD FRONT ASSOCIATED WITH THE LOW PRESSURE SYSTEM
MOVES ACROSS THE REGION (ACTUALLY IT MAY BE MORE OF AN OCCLUDED
FRONT AT THAT POINT). LOWS RANGING FROM THE UPPER 50S TO MIDDLE 60S.
THURSDAY...WRAP AROUND SHOWERS ARE POSSIBLE ACROSS EASTERN UPPER AND
FAR NORTHERN LOWER...ESPECIALLY IN THE MORNING. COOLER WITH HIGHS
ONLY IN THE UPPER 60S AND LOWER 70S.
&&
.LONG TERM...(FRIDAY THROUGH MONDAY)
ISSUED AT 328 AM EDT TUE AUG 18 2015
HIGH PRESSURE BUILDS IN FRIDAY WHICH SHOULD HOLD ON THROUGH SATURDAY
NIGHT YIELDING WARMER AND DRIER CONDITIONS. ANOTHER AREA OF LOW
PRESSURE TRACKING BY TO OUR NORTHWEST WILL THEN BRING MORE CHANCES
FOR SHOWERS AND THUNDERSTORMS SUNDAY...WITH WRAP AROUND DRIVEN
SHOWERS POSSIBLY LINGERING INTO MONDAY (MODELS ARE NOT IN AGREEMENT
HERE BUT PLENTY OF TIME TO MAKE ADJUSTMENTS). HIGHS BACK IN THE
UPPER 70S AND LOWER 80S FRIDAY THROUGH SUNDAY. COOLER AGAIN FOR
MONDAY WITH HIGHS IN THE UPPER 60S AND LOWER 70S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 655 AM EDT TUE AUG 18 2015
SOME IMPROVEMENT IN FLYING CONDITIONS TODAY. BRIEF VSBY POSSIBLE
AT JUST ABOUT ANY TIME IN SHRA.
STALLED COLD FRONT IS LAID OUT ACROSS CENTRAL LOWER MI. THIS
FRONT WILL WOBBLE ACROSS CENTRAL AND NORTHERN LOWER MI TODAY AND
TONIGHT. CONSIDERABLE SHRA AND A FEW TSRA WILL BE SEEN NORTH OF
THE FRONT...ESPECIALLY FROM LATE MORNING TODAY THRU TONIGHT. BRIEF
VSBY RESTRICTIONS WILL BE POSSIBLE. APN IS CURRENTLY IFR...OTHER
SITES VFR. APN WILL SEE IMPROVEMENT AS THE DAY PROCEEDS.
WINDS WILL BE LIGHT SOUTHERLY TO EASTERLY.
&&
.MARINE...
ISSUED AT 328 AM EDT TUE AUG 18 2015
A STALLED FRONT WILL WOBBLE ACROSS CENTRAL LOWER MI TODAY...BEFORE
MOVING NORTH TONIGHT AS A WARM FRONT. SE-ERLY WINDS WILL BE LIGHT
THRU THIS EVENING...BUT INCREASE OVERNIGHT. SMALL CRAFT
ADVISORIES WILL LIKELY BE NEEDED ON SOME WATERS BY WEDNESDAY
AFTERNOON. A STRONG COLD FRONT WILL CROSS THE REGION LATE
WEDNESDAY...WITH STRONG TO POTENTIALLY SVR THUNDERSTORMS.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
NEAR TERM...JAZ
SHORT TERM...SULLIVAN
LONG TERM...SULLIVAN
AVIATION...JAZ
MARINE...JAZ
AREA FORECAST DISCUSSION
NWS RALEIGH NC
700 AM EDT TUE AUG 18 2015
.SYNOPSIS...SOUTHWEST FLOW WILL TRANSPORT MOISTURE-RICH AIR INTO
CENTRAL NORTH CAROLINA. MEANWHILE A SERIES OF UPPER LEVEL
DISTURBANCES EMBEDDED IN THIS FLOW WILL MOVE ACROSS THE AREA. THE
COMBINATION OF THESE FEATURES WILL RESULT IN ENHANCED RAIN CHANCES
THROUGH MUCH OF THE WEEK.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 700 AM TUESDAY...
CURRENT FORECAST ON TRACK WITH RADAR SHOWING A SHIELD OF LIGHT RAIN
MOVING W TO E ACROSS NORTH-CENTRAL NC ATTM...ALONG AND AHEAD OF AN
MID/UPPER VORT MOVING ACROSS THE NC FOOTHILLS ATTM. MADE SOME TWEAKS
TO THE GRIDS FOR THE NEXT FEW HOURS TO SHOW CATEGORICAL POPS ACROSS
OUR NORTHERN ZONES...AND CHANCE POPS SOUTH. AS THIS FEATURE MOVES
NE LATER THIS MORNING...WE`RE STILL LOOKING FOR THE PRECIP TO
TRANSITION TO MORE SCATTERED/SHOWER IN NATURE...WITH SHOWERS AND
PERHAPS A FEW ISOLD TSTMS DEVELOPING/EXPANDING IN COVERAGE FROM W TO
E ACROSS THE REST OF CENTRAL NC DURING THE LATE MORNING AND
AFTERNOON HOURS.
PREV NEAR TERM DISC AS OF 235 AM TUESDAY...
LATEST MESOANALYSIS SHOWS THAT MOISTURE IS INCREASING FROM THE SOUTH
AS EXPECTED...AS THE PATTERN CONTINUES TO EVOLVE AND FLOW BECOMES
MORE UNIFORM FROM THE SOUTH AND SOUTHWEST. LATEST WATER VAPOR SHOWS
THE OLD CLOSED LOW OVER THE LOWER OH VALLEY HAS OPENED UP AND LIFTED
NORTH UP OVER INDIANA...AND HAS BECOME EMBEDDED WITHIN THE LONGWAVE
TROUGH DEEPENING OVER THE MIDDLE OF THE COUNTRY. EXTENDING SOUTH
FROM THIS WAVE IS A SHEAR AXIS THAT EXTENDS ACROSS THE APPALACHIANS
AND INTO UPSTATE SC. THIS FEATURE...COUPLED WITH THE NORTHWARD SURGE
OF MOISTURE...HAS PROVIDED THE MECHANISM AND FORCING FOR THE CURRENT
AREA OF LIGHT RAIN NOW MOVING ACROSS THE TRIAD REGION SOUTH TO THE
CHARLOTTE AREA. THE AREA OF RAIN ACROSS UPSTATE SC IS ALONG AND
AHEAD OF THE SHORTWAVE AT THE TAIL END OF THE AFOREMENTIONED SHEAR
AXIS. THESE FEATURES ARE PROGGED TO LIFT TO THE ENE TODAY...AND
LATEST CAMS INCLUDING THE HRRR WELL-DEPICT THESE FEATURES AND
SUGGESTS THAT THE TWO AREAS OF LIGHT RAIN WILL SPREAD EAST ACROSS
CENTRAL NC THIS MORNING INTO THE EARLY AFTERNOON. GIVEN THE
EXTENSIVE CLOUD COVER AND LIMITED INSTABILITY...WE EXPECT THE PRECIP
TO REMAIN STRATIFORM AND MAINLY LIGHT THROUGH THE MORNING HOURS.
THEN AS THE SHEAR AXIS BEGINS TO LIFT TO OUR NORTH...WE MAY BEGIN TO
SEE BREAKS IN THE CLOUDS AND SOME SUNSHINE LATE THIS MORNING AND
DURING THE AFTERNOON...WHICH WILL ALLOW FOR THE REMAINING PRECIP TO
TRANSITION TO MORE CONVECTIVE AND SCATTERED IN NATURE...WITH PERHAPS
SOME THUNDER AND LOCALIZED HEAVY DOWNPOURS. GIVEN THE HIGH PWAT
ENVIRONMENT AND SLOW MOVEMENT...LOCALIZED POOR DRAINAGE FLOODING
WILL BE THE PRIMARY IMPACT CONCERN WITH THE HEAVIER CELLS THIS
AFTERNOON. AS FOR TEMPS...MAV AND MET CONTINUE TO EXHIBIT A WIDE
SPREAD IN FORECAST VALUES FOR TODAY...WITH THE COOLER MAV SUGGESTING
READINGS RANGING FROM THE UPPER 70S NW TO MID 80S S/SE...WHILE THE
NAM IS SEVERAL DEGREES WARMER ACROSS THE TRIAD AND TRIANGLE REGIONS.
WITH THE CLOUD AND PRECIP COVERAGE THE PRIMARY FACTORS...WE FEEL
THAT A BLEND OF THE TWO IS WARRANTED BECAUSE SOME SUNSHINE IS
EXPECTED THIS AFTERNOON...ESP SOUTH OF HWY 64. THUS...HIGHS AROUND
80 ACROSS THE TRIAD...LOW-MID 80S TRIANGLE...MID 80S S OF HWY 64.
THE CHANCE FOR SCATTERED SHOWERS AND ISOLD TSTMS WILL CONTINUE
TONIGHT AS SEVERAL WEAK DISTURBANCES EMBEDDED IN THE SW FLOW
TRAVERSE THE AREA. LOWS WITHIN A COUPLE DEGREES OF 70.
&&
.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
AS OF 235 AM TUESDAY...
LITTLE CHANGE IN THE PATTERN...WHICH WILL FEATURE A LONGWAVE TROUGH
OVER THE MIDDLE OF THE COUNTRY AND A RIDGE EXTENDING ACROSS FL INTO
THE GOMEX. SW FLOW BETWEEN THESE FEATURES ACROSS THE SOUTHEAST
STATES WILL KEEP THE FLOW OF MOISTURE-RICH AIR INTO OUR AREA GOING.
THAT COUPLED WITH A SERIES OF DISTURBANCES EMBEDDED WITHIN THE SW
FLOW WILL MEAN THE RISK FOR SCATTERED SHOWERS AND TSTMS WILL
CONTINUE ACROSS OUR AREA THROUGH THE PERIOD. THE SCATTERED NATURE OF
THE SHOWERS AND TSTMS MEANS IT WON`T BE RAINING DURING THE ENTIRE
TIME...BUT IT WORTH POINTING OUT THAT ANY OF THE HEAVIER CELLS WILL
BE CAPABLE OF PRODUCING HEAVY DOWNPOURS AND LOCALIZED POOR DRAINING
FLOODING. WITH ENHANCED CLOUDINESS AND RAIN CHANCES...TEMPS SHOULD
REMAIN A DEGREE OR TWO BELOW NORMAL. HIGHS FROM THE MID 80S NORTH
TO UPPER 80S SOUTH. LOWS WEDNESDAY NIGHT 70-73.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 235 AM TUESDAY...
FOR THE PERIOD THURSDAY AND THURSDAY NIGHT...500MB HEIGHTS ARE
FORECAST BY BOTH THE NAM AND THE GFS TO RISE THURSDAY INTO THURSDAY
NIGHT. THIS SHOULD SERVE TO BOTH SLOW AND WEAKEN THE SURFACE FRONT
MOVING INTO CENTRAL NORTH CAROLINA. WIND SPEEDS GENERALLY LIGHTEN
THROUGH THE COLUMN WHICH SHOULD LIMIT LOW-LEVEL CONVERGENCE AS WELL
AS ANY DIFFLUENCE ALOFT. 850MB LIFT IS WEAK...BEST THURSDAY NIGHT
COMPARED TO DURING THE DAY THURSDAY...WHEN THE GFS IS ACTUALLY DRY
OVER MUCH OF CENTRAL NORTH CAROLINA. PRECIPITABLE WATER VALUES...
THOUGH...ARE STILL FORECAST IN VICINITY OF TWO INCHES WITH HIGH K
INDICES AND DECENT 850MB THETA-E VALUES. THE GFS ALSO FORECASTS A
MODEST 700MB SHORTWAVE MOVING THROUGH CENTRAL NORTH CAROLINA DURING
THE DAY AND EVENING...WITH PRONOUNCED 700MB NVA LATE THURSDAY NIGHT.
CONSIDERING THE AVAILABLE MOISTURE...MODEST INSTABILITY EVEN ON THE
GFS WITH MUCAPE OF 500-1000J/KG...AND THE NAM FORECAST OF GREATER
LOW-LEVEL CONVERGENCE WITH MORE OF A SOUTHERLY SURFACE WIND AS
OPPOSED TO THE MORE WESTERLY GFS FORECAST...PRUDENT TO CONTINUE AT
LEAST A CHANCE OF SHOWERS AND A THUNDERSTORM OR TWO FOR THIS PART OF
THE FORECAST. THIS DESPITE THE SINGLE-DIGIT MAV MOS POPS AT KRDU AND
KFAY FOR THE DAY THURSDAY. HIGHS FOR THURSDAY ARE A LITTLE TOUGH TO
GAUGE ANTICIPATING CONSIDERABLE CLOUD COVER THAT COULD BE OFFSET BY
EVEN SLIGHT PERIODS OF SUN GIVEN THE HIGH 1000-850MB THICKNESSES.
GUIDANCE HIGHS ARE 90 TO 95 AND WILL PLAN TO GO BELOW THOSE ROUGHLY
A COUPLE OF DEGREES. OVERNIGHT LOWS THURSDAY NIGHT WITHIN A DEGREE
OR THREE OF 70.
FRIDAY THROUGH MONDAY...THE SLOW-MOVING SURFACE FRONT SHOULD BE
LOCATED OVER THE EASTERN CAROLINAS...GRADUALLY MOVING SOUTH WHILE
LIKELY WASHING OUT INTO THE EARLY PART OF THE WEEKEND. AS SURFACE
HIGH PRESSURE IS FORECAST TO NUDGE SOUTH BEHIND THE FRONT...COARSE
MODEL SOUNDINGS FROM BOTH THE GFS AND THE ECMWF SUGGEST
PRECIPITATION CHANCES MAY BE MORE LIMITED FRIDAY...RELATIVELY HIGHER
TOWARD INTERSTATE 95 CLOSER TO THE FRONT. CONTINUED WITH A SLIGHT
CHANCE FOR SHOWERS FRIDAY OVER THE WESTERN PIEDMONT WITH CHANCES
MAINLY ALONG AND EAST OF U.S. 1...ALTHOUGH IF THE MODEL SOUNDINGS
VERIFY THESE CHANCES MAY END UP BEING TOO HIGH. EVEN IF SHOWER
CHANCES ARE LESS BOTH THE GFS AND ECMWF PROVIDE FOR DECENT MEAN
MOISTURE AND PARTICULARLY UPPER-LEVEL MOISTURE LINGERING WHICH WOULD
MAKE THE DAY PARTLY SUNNY AT BEST.
OVER THE WEEKEND...THE SURFACE FRONT SHOULD DIMINISH JUST SOUTH OF
CENTRAL NORTH CAROLINA SATURDAY AS WEAK HIGH PRESSURE BUILDS IN.
UNDER RIDGING ALOFT SATURDAY...ANY SHOWERS SHOULD BE DIFFICULT TO
COME BY. WILL RETAIN A SLIGHT CHANCE OF A SHOWER TOWARD INTERSTATE
95 WHERE MOISTURE OVERALL SHOULD BE A LITTLE HIGHER AND SURFACE
PRESSURES A LITTLE LOWER...WITH LIFT POSSIBLY AIDED BY A SEA BREEZE.
HEIGHTS ALOFT START TO FALL SUNDAY INTO MONDAY AHEAD OF ANOTHER
SURFACE FRONT THAT SHOULD BE MOVING TOWARD CENTRAL NORTH CAROLINA
FROM THE NORTHWEST. COARSE ECMWF MODEL SOUNDINGS ARE FAIRLY CAPPED
SUNDAY WHILE GFS COARSE MODEL SOUNDINGS SHOW COOLER TEMPERATURES
ALOFT AND GREATER INSTABILITY...ENOUGH FOR AT LEAST ISOLATED/SLIGHT
CHANCES FOR SHOWERS SUNDAY WITH THE RELATIVELY HIGHER CHANCES THAT
DAY OVER THE WESTERN PIEDMONT WHERE ANY INSTABILITY SHOULD BE
GREATER.
BY MONDAY...TIMING DIFFERENCES WITH THE APPROACH OF THE SURFACE
FRONT ENSURE CONTINUATION OF CHANCES FOR SHOWERS AND STORMS THEN...
HIGHEST EARLIER MONDAY OVER THE WESTERN PIEDMONT THEN CHANCES
THROUGHOUT CENTRAL NORTH CAROLINA BY MONDAY AFTERNOON THROUGH MONDAY
NIGHT. BOTH THE ECMWF AND GFS COARSE MODEL SOUNDINGS SHOW SUFFICIENT
INSTABILITY AND LAYER LAPSE RATES FOR AT LEAST SCATTERED SHOWERS AND
THUNDERSTORMS ACROSS THE AREA BY MONDAY AFTERNOON. FOR HIGH
TEMPERATURES...LEANED TOWARD THE MEE MOS GUIDANCE WHICH SEEMED TO BE
A GOOD BLEND BETWEEN THE COOLER MEX MOS AND WARM 1000-850MB
THICKNESSES. HIGHS 85 TO 90 FRIDAY AND 87 TO 92 BY MONDAY. OVERNIGHT
LOWS MOSTLY 65 TO 70... ABOUT A CATEGORY COOLER SATURDAY NIGHT WHEN
IT WOULD SEEM THERE WOULD BE THE GREATER CHANCE OF A COMBINATION OF
SOMEWHAT DRIER LOW-LEVEL AIR AND AREAS OF CLEARING.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 700 AM TUESDAY......
THROUGH 12Z WED: RADAR CONTINUES TO SHOW A SHIELD OF LIGHT RAIN
MOVING W TO E ACROSS NORTH CENTRAL NC. FLT CONDITIONS UNDER THIS
RAIN ARE MOSTLY LOW-VFR OR MVFR...WITH LOCAL IFR BEING REPORTED
INVOF OF THE STRONGER RAIN ECHOES. AS THE MORNING PROGRESSES...WE
EXPECT THE RAIN TO TRANSITION TO MORE SHOWER (CONVECTIVE) IN
NATURE...WITH ADDITIONAL SCATTERED SHOWERS DEVELOP ACROSS THE
REMAINDER OF CENTRAL NC. WHILE IT WON`T BE RAINING EVERYWHERE AND
ALL DAY...WHERE IT IS RAINING EXPECT MVFR OR UPPER-IFR CONDITIONS.
ISOLD TSTMS ARE ALSO POSSIBLE THIS AFTERNOON...WHICH WILL RESULT IN
LOCAL DOWNPOURS AND IFR CONDITIONS...AND VARIABLE WINDS BRIEFLY
GUSTING UP TO 30KT. AFT 19/01Z...EXPECT LOW-VFR CONDITIONS WITH CIGS
AROUND 5K FT. PATCHY FOG IS POSSIBLE LATE OVERNIGHT...PARTICULARLY
INVOF SITES THAT RECEIVED HEAVIER RAIN DURING THE DAY.
AFTER 12Z WED: WITH LITTLE CHANGE IN THE PATTERN THROUGH THE REST OF
THE WEEK...LOOK FOR SCATTERED SHOWERS AND TSTMS WHICH WILL RESULT IN
LOCALIZED MVFR OR IFR CONDITIONS. VFR CONDITIONS OUTSIDE OF SHOWER
AND TSTM ACTIVITY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RAH
NEAR TERM...RAH
SHORT TERM...RAH
LONG TERM...DJF
AVIATION...RAH
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
750 AM EDT TUE AUG 18 2015
.SYNOPSIS...
A WEAKENING UPPER AIR DISTURBANCE WILL SLIDE THROUGH THE AREA
TODAY. A STRONGER DISTURBANCE WILL MOVE INTO AND THROUGH THE
REGION LATER WEDNESDAY AND THURSDAY. DRIER CONDITIONS WILL RETURN
FOR THE END OF THE WEEK AND WEEKEND AS TEMPERATURES FALL BACK TO
NEAR NORMAL.
&&
.NEAR TERM /THROUGH TONIGHT/...
RADAR SHOWS AN MCS MOVING SLOWLY NORTH INTO FAR SWRN PA...WITH
THE EASTERN EXTENT OF THE RAIN EXTENDING FROM THE SOUTHERN LAURELS
DOWN INTO WEST VA. THIS IS ASSOCIATED WITH A SHEARING OUT
SHORTWAVE AND AN AREA OF WARM ADVECTION AND LOW LEVEL CONVERGENCE.
THE HRRR AND RAP CONFINE THE SHOWERS TO MY FAR WESTERN ZONES
THROUGH LATE MORNING BEFORE GENERATING MORE SPOTTY SCATTERED
SHOWERS AND STORMS FOR THE AFTERNOON.
WHAT`S LEFT OF THE WEAKENING SHORTWAVE WILL TRAVERSE THE REGION
TODAY WITH THE BEST CHANCE FOR RAIN BEING OVER THE WEST...AND
CHANCES DIMINISHING OVER CENTRAL AND EASTERN AREAS. WOULD NOT BE
SURPRISED IF THE LOWER SUSQ SEES MUCH OF ANY RAIN AT ALL.
IT WILL BE ANOTHER WARM-HUMID DAY...BUT THE CLOUDS AND SCATTERED
SHOWERS WILL LIKELY SHAVE A FEW DEG OFF YESTERDAYS READINGS.
TIMING THE SHORTWAVE IN THE MODEL GUIDANCE SUGGESTS WE WILL
EXPERIENCE A BIT OF A LULL IN THE SHOWERY CONDITIONS
OVERNIGHT...ESPECIALLY THE SECOND HALF OF THE OVERNIGHT. ANOTHER
MUGGY NIGHT IS IN STORE WITH LOWS GENERALLY IN THE MID 60S TO
LOWER 70S...SOME 10-15 DEF ABOVE NORMAL.
&&
.SHORT TERM /WEDNESDAY/...
AFTER A SHORT PERIOD OF WEAK RIDGING ALOFT TONIGHT IN THE WAKE OF
THE DEPARTING SHORTWAVE...WEDNESDAY WILL FEATURE HEIGHTS ALOFT
BEGINNING TO FALL ONCE AGAIN...ESPECIALLY THE LAST PART OF THE
DAY AS THE LARGE ANOMALOUSLY DEEP TROUGH OVER THE UPPER MIDWEST
BEGINS TO MOVE INTO THE WESTERN GR LAKES AND SOUTHERN CANADA. THE
CHANCES FOR SHOWERS WILL ONCE AGAIN BE ON THE RISE AS ANOTHER SHOT
OF DEEP MOISTURE ADVECTS INTO THE AREA ON A STRENGTHENING DEEP
SOUTHWESTERLY FLOW. THE GEFS SHOWS THE PWATS INCREASING TO 2-3 STD
DEV ABOVE NORMAL DURING THE DAY WED. THOUGH I PRETTY MUCH
BROADBRUSHED THE CHANCE FOR SCATTERED SHOWERS AND
STORMS...THINKING IS THE AFTERNOON WILL SEE THE BEST CHANCE OF
RAIN OVER MOST OF MY AREA.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
THERE IS PRETTY GOOD AGREEMENT THAT THE ANOMALOUSLY DEEP SYSTEM
TO OUR WEST WILL QUICKLY SHEAR OUT AND BRING THE MAIN SURGE OF
PRECIP/FORCING INTO THE LOCAL AREA THURSDAY.
I HAVE SOME CONCERN FOR LOCALIZED HEAVY RAINS DEVELOPING AS THE
SHORT RANGE MODELS SUGGEST THE FRONT WILL SLOW DOWN AS THE UPPER
JET SURGES INTO SOUTHERN CANADA. STRONG LOW LEVEL FRONTOGENETIC
FORCING IS INDICATED AS THE WAVY FRONT MOVES SLOWLY THROUGH
CENTRAL AND EASTERN AREAS. LATEST ENSEMBLES SHOW A SMALL PROB OF
1" OR MORE AMOUNTS OVER CENTRAL AND EASTERN AREAS THURSDAY
AFTERNOON AND EVENING...WITH THE ECMWF EVEN HINTING THAT AN AREA
OF HEAVY RAIN COULD LINGER INTO THURSDAY NIGHT OVER MOST OF MY
EASTERN ZONES.
GUIDANCE SUGGESTS THE FRONT IS BASICALLY EAST OF THE FORECAST AREA
BY FRIDAY...WITH PERHAPS FAR EASTERN AREAS STILL SEEING A
LINGERING SHOWER THREAT. BUT DRIER AIR MOVING IN BEHIND THE FRONT
LOOKS LIKE A HIGH CONFIDENCE FORECAST FOR FRIDAY AND
SATURDAY...BEFORE THINGS GET POTENTIALLY MUDDY ONCE AGAIN FOR THE
END OF THE WEEKEND.
WEAK TROUGHING ALOFT AND THE SURFACE HIGH SLIDING OFF THE NEW
ENGLAND COAST COULD CONSPIRE TO BRING THE CHANCES FOR SOME
SHOWERS...OR MAYBE EVEN LOW CLOUDS AND LIGHT RAIN OR DRIZZLE AS
DEPICTED IN THE OPERATIONAL GFS BACK INTO THE AREA FOR SUNDAY. I
KEPT THE CHANCES LOW...BUT HAVE LITTLE CONFIDENCE IN THE FORECAST
THAT FAR OUT.
IT WILL REMAIN WARM WITH DAILY HIGHS AVERAGING ABOVE NORMAL
THROUGHOUT THE PERIOD.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
12Z TAFS SENT.
DID ADJUST SOME...BULK OF SHOWERS AND STORMS LOOKS
TO BE LIFTING NW OF OUR AREA.
EXPECT MORE IN THE WAY OF FOG TONIGHT...AS DEWPOINTS
COME UP SOME.
EARLIER DISCUSSION BELOW.
SOME SHOWERS AND THUNDERSTORMS TODAY...AS A WEAK SYSTEM LIFTS
NORTHWARD. FAR SE AREAS SUCH AS LNS...MAY SE LITTLE IF ANY RAIN
BEFORE LATE AFT.
MORE IN THE WAY OF SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE
ON WED INTO THU...AS A RATHER DEEP SYSTEM LIFTS NE TOWARD THE
LAKES.
HOWEVER...TREND WILL BE FOR SYSTEMS TO LIFT NW OF OUR AREA.
THIS WILL TREND TO TAPER THE AMT OF COLD AIR BEHIND THE
FRONTS AND ANY STORMS THAT FORM ALONG THE FRONT.
OUTLOOK...
WED...ISOLD PM TSRA IMPACTS POSS W MTNS.
THU...AM LOW CIGS/FOG POSS. SCT/NUMEROUS PM TSRA IMPACTS
POSSIBLE.
FRI-SAT...NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LA CORTE
AVIATION...MARTIN
AREA FORECAST DISCUSSION...UPDATED
NWS LUBBOCK TX
653 AM CDT TUE AUG 18 2015
.UPDATE...
SHOWER AND T-STORM ACTIVITY ALONG THE TX-NM STATE LINE HAS
GRADUALLY CONGEALED INTO A BROAD BLOB OF MAINLY LIGHT RAIN...BUT
WITH A FEW EMBEDDED T-STORMS...MAINLY OVER COCHRAN AND YOAKUM
COUNTIES. WE HAVE UPPED POPS CONSIDERABLY IN THIS AREA FOR THE
MORNING HOURS. ELSEWHERE...SOME ADDITIONAL DEVELOPMENT IS NOTED
ACROSS FLOYD AND BRISCOE COUNTIES...BUT WE HAVE KEPT THE ISOLATED
MENTION IN PLACE FOR NOW.
&&
.AVIATION...
SCATTERED -SHRA AND MORE ISOLATED -TSRA COULD AFFECT ANY OF THE
TERMINALS THROUGH 15 OR 16 UTC. WE HAVE GONE AHEAD AND ADDED TEMPO
GROUPS AT KLBB AND KPVW TO COVER THIS POTENTIAL. TSRA WILL THEN RETURN
TO THE FORECAST THIS EVENING AS A COLD FRONT MOVES IN FROM THE
NORTH. AT THIS TIME...CONFIDENCE IS TOO LOW IN THE TIMING AND
COVERAGE OF TSRA TO INCLUDE IN THE FORECASTS. ALSO...THE EXACT
TIME OF THE FROPA THROUGH THE TERMINALS REMAINS UNCERTAIN DUE TO
POSSIBLE INTERACTION WITH T-STORM OUTFLOWS.
&&
.PREV DISCUSSION... /ISSUED 402 AM CDT TUE AUG 18 2015/
SHORT TERM...
WATER VAPOR IMAGERY SHOWS A SHARP SHORTWAVE TROUGH CROSSING THE
ROCKIES AND EMERGING OVER THE CENTRAL AND NRN PLAINS THIS MORNING.
THIS IS PRODUCING SCATTERED CONVECTIVE ACTIVITY FROM
NEBRASKA...ARCING EAST INTO CENTRAL KS...THEN BACK SW ACROSS NW OKLA
AND ERN TX PANHANDLE...AND INTO ERN AND SRN NEW MEXICO. THIS
ACTIVITY IS MOSTLY SPLITTING OUR FORECAST AREA AT 3 AM...WITH THE
EASTERN BATCH JUST NICKING OUR NE COUNTIES AND THE WESTERN BATCH
STAYING WEST OF THE STATE LINE. HOWEVER...RADAR IS SHOWING A SLIGHT
UPTICK IN COVERAGE AND INTENSITY AT THIS TIME...AND THE HRRR AND RAP
SUGGEST THAT ISOLATED TO SCATTERED COVERAGE OF SHOWERS AND STORMS
WILL WORK THEIR WAY SEWD ACROSS MOST OF OUR FORECAST AREA THIS
MORNING. THE ACTIVITY WILL TEND TO WANE TOWARD SUNRISE...AND AT
THIS TIME IT LOOKS LIKE AN ISOLATED MENTION IN THE FORECAST AFTER
12 UTC WILL BE SUFFICIENT.
IT NOW APPEARS THAT MOST OF THE DAY WILL BE PRETTY QUIET AS MODEST
SUBSIDENCE REPLACES THE MODEST LIFT MOVING THROUGH THIS MORNING.
THIS SHOULD ALLOW TEMPS TO WARM A FEW DEGREES FROM YESTERDAY/S
READINGS WITH HIGHS EXPECTED TO TOP OUT IN THE LOWER 90S NORTHWEST
TO NEAR 100 IN THE SOUTHEAST. MEANWHILE...THE MUCH ANTICIPATED COLD
FRONT....CURRENTLY MOVING THROUGH ERN COLO AND WRN KS...WILL BE
MAKING IT/S WAY SOUTH THROUGH THE PANHANDLES. THE LATEST HIGH-RES
GUIDANCE IS IN GOOD AGREEMENT THAT AN INITIAL WIND SHIFT WILL WORK
INTO THE FAR SW TX PANHANDLE AND NW SPLNS BY EARLY AFTERNOON...BUT
THEN NOT MAKE MUCH ADDITIONAL PROGRESS THROUGH EARLY EVENING. THIS
WILL SET UP A SURFACE TROUGH RUNNING FROM THE WRN SOUTH PLAINS
INTO THE SRN TX PANHANDLE. DESPITE A NICE BUILDUP OF CAPE TO NEAR
3000 J/KG IN THIS AREA...THE CAP IS EXPECTED TO HOLD THROUGH MOST
OF THE AFTERNOON. LARGE-SCALE ASCENT SHOULD BEGIN TO INCREASE
EARLY THIS EVENING AS THE NEXT VORT MAX SWINGS ACROSS THE SRN
ROCKIES. ALTHOUGH THE BULK OF THIS LIFT WILL BE OFF TO OUR
NORTH...IT SHOULD TRIGGER SOME T-STORM DEVELOPMENT AS IT SPREADS
OVER THE FRONT AND SURFACE TROUGH. UNFORTUNATELY...MODEL GUIDANCE
REMAINS HIGHLY VARIABLE AND INCONSISTENT IN THE PLACEMENT AND
COVERAGE OF QPF AND MODEL REFLECTIVITY FIELDS...INCLUDING A FEW
SOLUTIONS...SUCH AS THE 00 UTC TTU-WRF...WHICH KEEPS THE FORECAST
AREA MOSTLY PRECIP FREE. AS SUCH...OUR CONFIDENCE REMAINS LOW
REGARDS THE EXTENT OF THUNDERSTORMS THIS EVENING AND THUS POPS ARE
ONLY IN THE 20 TO 40 PERCENT RANGE....MAXIMIZED ACROSS THE FAR SE
TX PANHANDLE. THE AVAILABLE INSTABILITY AND DEEP-LAYER SHEAR
SUPPORT THE IDEA OF SOME STORM ORGANIZATION AND A SEVERE WEATHER
THREAT...FOCUSED ON THE FAR SRN TX PANHANDLE AND NW
SPLNS...ALTHOUGH THE COVERAGE MAY BE JUST TOO LIMITED TO BE OF
SIGNIFICANT IMPACT.
THE COLD FRONT WILL SURGE THROUGH THE FORECAST AREA OVERNIGHT...WITH
BREEZY NE WINDS EXPECTED WITH THE FROPA EVEN OUTSIDE OF ANY T-STORM
ACTIVITY. LOW STRATUS WILL ALSO EXPAND IN COVERAGE BEHIND THE FRONT.
THE BEST RAIN CHANCES WILL GRADUALLY SHIFT EWD INTO THE ROLLING
PLAINS EARLY WEDNESDAY MORNING.
LONG TERM...
MUCH COOLER AIR WILL BE ADVECTING INTO THE SOUTH PLAINS ON GUSTY
NORTHEASTERLY WINDS WEDNESDAY BEHIND THE EARLY DAY FROPA. SUSTAINED
WINDS NEAR 20 KNOTS COUPLED WITH HIGHS ONLY CLIMBING INTO THE 70S
FOR MOST SPOTS WILL MAKE FOR A FALL-LIKE FEEL IN THE AIR. IN
ADDITION...MOIST UPGLIDE ABOVE THE FRONTAL ZONE WILL YIELD A STRATUS
DECK WITH ENOUGH ELEVATED INSTABILITY PERHAPS SUPPORTING A RISK OF A
FEW SHOWERS/STORMS ACROSS THE EASTERN AND SOUTHEASTERN ZONES. OF
NOTE...THE RECORD MINIMUM HIGH FOR AUGUST 19TH IN LUBBOCK IS 74
DEGREES /SET IN 1956/ AND THIS COULD BE THREATENED IF CLOUDS HANG
TOUGH ALL DAY. SURFACE RIDGING WILL THEN SETTLE OVER THE REGION WITH
LIGHT WINDS AND THE COOLEST AIR SINCE LATE MAY. DEPENDING ON WHETHER
SKIES COMPLETELY CLEAR AND EXACTLY HOW LOW DEWPOINTS CAN DROP WITHIN
THE RIDGE...WE COULD ALSO THREATEN THE RECORD LOW THURSDAY MORNING
/THE CURRENT RECORD IS 54 DEGREES SET IN 1915/.
THE SURFACE RIDGE WILL SLIDE EASTWARD ON THURSDAY ALLOWING SOUTHERLY
WINDS TO GRADUALLY RETURN AND COUPLED WITH INCREASED INSOLATION
HIGHS WILL REBOUND BACK INTO THE 80S. WE WILL THEN SEE SLIM STORM
CHANCES CREEP BACK INTO THE FORECAST THURSDAY NIGHT INTO FRIDAY AS
ONE OR MORE SUBTLE DISTURBANCES MOVE THROUGH THE QUASI-ZONAL FLOW
AND GRAZE THE AREA FROM THE NORTH. THE SUPPRESSED SOUTHWESTERN UPPER
RIDGE IS THEN FORECAST TO EXPAND NORTHWARD AND BRIDGE TO AN UPPER
HIGH CENTERED OVER FLORID THIS WEEKEND WHILE AT THE SAME TIME A
SHARP TROUGH MOVES STEADILY ACROSS THE NORTHERN TIER OF THE
NATION. THE BUILDING HEIGHTS AND PROLONGED SOUTHERLY FLOW WILL
ALLOW TEMPERATURES TO MODERATE BACK UP TO NEAR AVERAGE BY FRIDAY
AND SATURDAY. EVEN WITH THE RIDGE BUILDING MORE SQUARELY
OVERHEAD...A SUBTROPICAL MOISTURE FETCH ALONG WITH CONVERGENCE
ALONG A SURFACE TROUGH WILL KEEP LOW THUNDER CHANCES GOING ACROSS
THE WESTERN ZONES ON SATURDAY. THE NORTHERN STREAM SYSTEM WILL
THEN SEND A COLD FRONT SOUTHWARD INTO THE SOUTHERN PLAINS ON
SUNDAY BEFORE STALLING OUT SOMEWHERE NEARBY AND THEN WASHING OUT
EARLY NEXT WEEK. THIS FRONT WILL PROVIDE AT LEAST A SLIM SHOT OF
ADDITIONAL CONVECTION ON SUNDAY...THOUGH WITHOUT ANY UPPER SUPPORT
COVERAGE WOULD LIKELY BE NO BETTER THAN SCATTERED.
AFTER ANOTHER BRIEF AND LESS DRAMATIC COOL DOWN /THAN ON
WEDNESDAY/ WITH THE FRONT LATE THIS WEEKEND...HOTTER AND DRY
WEATHER SHOULD FOLLOW. THIS WILL OCCUR AS UPPER RIDGING IS
PROGGED TO AMPLIFY OVER THE SOUTHERN ROCKIES INTO THE SOUTHERN
HIGH PLAINS DURING THE EARLY AND MIDDLE PARTS OF NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 92 58 75 53 / 20 30 10 0
TULIA 91 60 74 54 / 20 40 20 0
PLAINVIEW 92 61 74 53 / 20 30 20 0
LEVELLAND 93 63 77 56 / 20 30 20 0
LUBBOCK 94 65 77 57 / 20 30 20 10
DENVER CITY 96 65 79 56 / 50 20 20 10
BROWNFIELD 94 65 79 56 / 20 30 20 10
CHILDRESS 96 67 78 58 / 20 40 30 10
SPUR 95 67 78 58 / 20 30 30 20
ASPERMONT 99 70 83 61 / 20 30 30 30
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
33/23/
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
625 AM CDT TUE AUG 18 2015
UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE
.SHORT TERM...TODAY...TONIGHT...AND WEDNESDAY
ISSUED AT 316 AM CDT TUE AUG 18 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A COLD
FRONT STRETCHING ACROSS SOUTHWEST TO EAST-CENTRAL WISCONSIN EARLY
THIS MORNING. A SECONDARY FRONT RUNS ACROSS SOUTHERN MINNESOTA TO
EASTERN LAKE SUPERIOR. WEAK FGEN COMBINED WITH LINGERING ELEVATED
INSTABILITY CONTINUE TO GENERATE SCATTERED SHOWERS ALONG BOTH
FRONTS. BETTER MOISTURE AND INSTABILITY RESIDES OVER IOWA AND THE
PLAINS WHERE THUNDERSTORMS ARE OCCURRING. LOOKING FURTHER
UPSTREAM...LOW PRESSURE IS DEVELOPING OVER NORTHEAST COLORADO AHEAD
OF A DIGGING SHORTWAVE TROUGH. PRECIP TRENDS ALONG THE FRONT AND
ASSOCIATED WITH THE SURFACE LOW ARE THE MAIN FORECAST CONCERNS.
MODELS HAVE SLOWED DOWN THE PROGRESSION OF SURFACE FEATURES
SOMEWHAT. THE GFS IS A CLEAR OUTLIER...PROBABLY DUE TO ITS RATHER
POOR INITIALIZATION. PREFER A BLEND OF THE NAM/ECMWF/GEM.
TODAY...AS LOW PRESSURE CONSOLIDATES OVER THE CENTRAL PLAINS...THE
PRIMARY COLD FRONT IS PROJECTED TO STALL OVER CENTRAL AND EAST-
CENTRAL WISCONSIN...NEAR OR JUST SOUTH OF THE SOUTHERN FORECAST AREA
BORDER. WILL PROBABLY SEE AN UPTICK OF SHOWER ACTIVITY THIS MORNING
WITH WEAK SHORTWAVES MOVING OVERHEAD. ONCE THESE SHORTWAVES PASS TO
THE EAST BY LATE MORNING...NORTHERN WISCONSIN MAY SEE A DRY PERIOD
SO REDUCED PRECIP CHANCES THERE. SCATTERED SHOWERS WILL STILL IMPACT
THE SOUTH...CLOSER TO THE STALLED FRONT. WILL LIKELY SEE SHOWERS AND
A FEW STORMS BECOME MORE WIDESPREAD OVER CENTRAL WISCONSIN LATE IN
THE AFTERNOON AS MID-LEVEL FLOW STRENGTHENS OVER THE BOUNDARY.
HIGHS RANGING FROM THE MID 60S NORTH TO MID 70S SOUTH.
TONIGHT...A STRONG AREA OF LOW PRESSURE WILL LIFT NORTHEAST TOWARDS
MINNEAPOLIS WHILE PUSHING A COLD FRONT INTO SOUTHWEST OR CENTRAL
WISCONSIN BY 12Z WED. AS LARGE-SCALE ASCENT INCREASES...SHOULD SEE
AREAS OF SHOWERS AND THUNDERSTORMS LIFT NORTHEAST ACROSS THE
FORECAST AREA. THE MOST POTENT SWATH OF STORMS SHOULD ARRIVE LATE
IN THE NIGHT AHEAD OF THE COLD FRONT AND CLOSED MID-LEVEL
CIRCULATION. THOUGH INSTABILITY WILL BE QUITE LOW...PWATS WILL BE
GREATER THAN 1.5 INCHES AND FORCING WILL BE EXCELLENT. WIND FIELDS
ALOFT WILL ALSO BE STRENGTHENING AS 850MB WINDS APPROACH 40-45 KTS.
THOUGH CONVECTION WILL LIKELY BE LOW TOPPED...ANY CONVECTION WILL BE
CAPABLE OF BRINGING DOWN THESE STRONGER WINDS. THEREFORE...A
MARGINAL RISK LOOKS REASONABLE FOR THE SOUTHWEST FORECAST AREA.
TEMPS WILL NOT FALL MUCH TONIGHT. LOWS AROUND 60 NORTH TO THE MID
60S SOUTH.
WEDNESDAY...LOW PRESSURE WILL SLOWLY MOVE NORTHEAST OVER FAR
NORTHWEST WISCONSIN AS THE COLD FRONT SWEEPS ACROSS NORTH-CENTRAL
AND NORTHEAST WISCONSIN. SHOWERS AND STORMS ARE A DECENT BET AHEAD
OF THE FRONT DURING THE MORNING...AND THE THREAT OF STRONG GUSTY
WINDS WILL ACCOMPANY ANY STORMS. THE FRONT WILL EXIT NORTHEAST
WISCONSIN BY MID TO LATE AFTERNOON ENDING ANY STORM THREAT. WRAP
AROUND LIGHT SHOWERS MAY SPREAD INTO NORTH-CENTRAL WISCONSIN BY
EARLY EVENING. HIGHS RANGING FROM THE MID 60S WEST TO MID 70S EAST.
.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY
ISSUED AT 316 AM CDT TUE AUG 18 2015
THE STRONG COLD FRONT AND UPPER LEVEL CYCLONE...THAT WILL IMPACT
THE AREA IN THE SHORT TERM...WILL DEPART THE REGION ON THEIR WAY
TOWARD HUDSON BAY DURING THE LATTER HALF OF THE WEEK. THE CHANCE
FOR RAIN WILL DECREASE AS THESE FEATURES DEPART...ENDING BY 00Z
FRIDAY. UPPER FLOW ACROSS THE REGION BRIEFLY BECOMES ZONAL...THEN
SOUTHWEST AS A WEST COAST TROUGH TRAVERSES THE CONUS. ANOTHER
COLD FRONT IS FORECAST TO MOVE ACROSS THE REGION OVER THE WEEKEND
ALONG WITH THE TROUGH. THIS WILL BRING CHANCES FOR THUNDERSTORMS
BACK TO THE AREA FROM SATURDAY NIGHT THROUGH SUNDAY NIGHT.
COLDER THAN NORMAL TEMPERATURES CAN BE EXPECTED THURSDAY BEFORE
FLOW ALOFT FLATTENS AND WARMER THAN NORMAL CONDITIONS RETURN FOR
FRIDAY AND SATURDAY. CLOUDS AND RAIN WILL KEEP HIGHS CLOSER TO
NORMAL ON SUNDAY. EXPECT COLDER THAN NORMAL TEMPERATURES ON MONDAY
BEHIND THE COLD FRONT.
&&
.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 625 AM CDT TUE AUG 18 2015
SCATTERED SHOWERS AND WIDESPREAD IFR CIGS WILL CONTINUE
NORTH OF A COLD FRONT OVER CENTRAL AND NORTHEAST WISCONSIN THROUGH
THE MORNING BEFORE CIGS RISE TO MVFR THIS AFTERNOON. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS WILL BE POSSIBLE THIS
AFTERNOON...AND CONDITIONS COULD FALL TO IFR IN THE HEAVIER
SHOWERS/STORMS. WIDESPREAD SHOWERS AND THUNDERSTORMS AND LOWERING
CIGS/VSBYS WILL OCCUR TONIGHT WHEN A LOW PRESSURE SYSTEM APPROACHES
THE UPPER MISSISSIPPI VALLEY. LIFR CIGS WILL BE LIKELY OVER N-C
WISCONSIN LATE TONIGHT.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......MG
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
608 AM CDT TUE AUG 18 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 401 AM CDT TUE AUG 18 2015
MAIN FORECAST CONCERNS TODAY ARE ON THE POTENTIAL FOR A FEW
STRONG STORMS THIS AFTERNOON AND EVENING ALONG WITH WIDESPREAD
RAINFALL.
LATEST WATER VAPOR SHOWED A VIGOROUS SHORTWAVE MOVING INTO
WESTERN SOUTH DAKOTA/NEBRASKA. MEANWHILE...SURFACE LOW PRESSURE
WAS STARTING TO DEEPEN ACROSS SOUTHERN NEBRASKA/NORTHERN KANSAS.
THE WAVE WILL CONTINUE TO DIG SOUTHEAST TODAY AND INTENSIFY AS IT
MAKES EASTWARD PROGRESS. THE SURFACE LOW IS EXPECTED TO LIFT
NORTHEAST AND CONTINUE TO DEEPEN AS IT PUSHES INTO NORTHWEST
IOWA/SOUTHWEST MINNESOTA THIS AFTERNOON AND EVENING AS IT FEEDS
ON A BAROCLINIC ZONE SITUATED SOUTHWEST TO NORTHEAST ACROSS THE
UPPER MISSISSIPPI RIVER VALLEY. A WARM FRONT WILL BE LIFTED
NORTHWARD ACROSS THE FORECAST AREA THIS AFTERNOON INTO THIS
EVENING AS THE LOW CONTINUES TO TRACK NORTHEAST. WIDESPREAD
SHOWERS AND THUNDERSTORMS WILL OVERSPREAD SOUTHEAST MINNESOTA AND
NORTHEAST IOWA THIS AFTERNOON AND ARE EXPECTED TO TRACK NORTHEAST
THROUGH AFTERNOON INTO THE EVENING HOURS THROUGH WESTERN INTO
CENTRAL WISCONSIN. RATHER IMPRESSIVE SHEAR PROFILES NOTED FOR THIS
AFTERNOON AND EVENING WITH 0-3 KM BULK SHEAR VALUES OF OF 25 TO 40
KTS. LOOKING AT FORECAST SOUNDINGS/HODOGRAPHS...SUFFICIENT SHEAR
NOTED IN THE 0-1 KM LAYER TO WARRANT A POSSIBLE ISOLATED TORNADO
THREAT WITH THE POSSIBILITY OF SEEING A FEW MINI
SUPERCELLS....ESPECIALLY CLOSER TO THE TRIPLE POINT THIS AFTERNOON
INTO EARLY THIS EVENING. THE MAJOR LIMITING FACTOR FOR THIS IS THE
LACK OF SURFACE BASED CAPE. NAM FORECAST SOUNDINGS SHOW ONLY
AROUND 300 J/KG WHICH IS ON THE LOWER END FOR A MINI SUPERCELL
ENVIRONMENT. WITH STRONG 0-1 KM AGL HELICITY OF 350 TO 400...WILL
HAVE TO KEEP A VERY CLOSE EYE ON ANY OF THE STRONGER CELLS TODAY.
THE ONGOING SHOWERS AND STORMS THIS MORNING INTO THIS AFTERNOON IN
AND AHEAD OF THE WARM SECTOR SHOULD LIMIT SURFACE BASED CAPE AND
THE OVERALL SEVERE WEATHER THREAT. THE MAIN THREAT FROM THE STORMS
LOOKS TO BE BRIEF HEAVY RAINFALL AND POSSIBLY SOME GUSTY WINDS OUT
OF ANY STRONGER CELLS.
THE LOW IS EXPECTED TO LIFT ACROSS EAST CENTRAL MINNESOTA AND INTO
NORTHWEST WISCONSIN LATE TONIGHT INTO EARLY WEDNESDAY MORNING
WITH A DRY SLOT PUSHING ACROSS THE FORECAST AREA. THE BULK OF THE
SHOWERS AND STORMS WILL LIFT NORTH OF THE FORECAST AREA.
DEFORMATION RAIN WILL PERSIST ACROSS NORTHERN AND WESTERN
MINNESOTA WEDNESDAY MORNING....THEN LOOKS TO WRAP INTO LATE
WEDNESDAY MORNING INTO WEDNESDAY AFTERNOON. THIS WILL BRING RAIN
SHOWERS TO AREAS MAINLY ALONG AND NORTH OF INTERSTATE 90.
WRAPAROUND RAIN SHOWERS WILL GRADUALLY TAPER OFF AND LIFT NORTH OF
THE FORECAST AREA WEDNESDAY NIGHT. THE BIG STORY FOR WEDNESDAY WILL
BE MUCH COOLER AIR MOVING INTO THE REGION WITH HIGH TEMPERATURES
STRUGGLING TO REACH THE LOWER TO MIDDLE 60S. WEDNESDAY WILL FEEL
MORE LIKE EARLY FALL WITH BREEZY WEST WINDS AND WELL BELOW NORMAL
HIGH TEMPERATURES.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 401 AM CDT TUE AUG 18 2015
DRY AND BREEZY CONDITIONS ARE EXPECTED ACROSS THE UPPER MISSISSIPPI
RIVER VALLEY ON THURSDAY AS FLOW ALOFT SWITCHES BACK TO ZONAL. IT
WILL BE A RATHER COMFORTABLE DAY WITH HIGHS IN THE LOWER TO
MIDDLE 70S. TEMPERATURES RETURN TO NORMAL LATE AUGUST VALUES ON
FRIDAY WHEN HIGHS REBOUND INTO THE UPPER 70S TO LOWER 80S. BREEZY
SOUTH WINDS ARE EXPECTED ACROSS THE REGION ON FRIDAY WITH A TIGHT
PRESSURE GRADIENT SETTING UP AS LOW PRESSURE DEVELOPS OVER THE
NORTHERN PLAINS. A TROUGH AND COLD FRONT PUSH EAST ACROSS THE
DAKOTAS LATE FRIDAY INTO SATURDAY. SATURDAY LOOKS TO BE ANOTHER
BREEZY DAY AHEAD OF THE APPROACHING COLD FRONT WITH SOUTH WINDS OF
15 TO 20 MPH. THE COLD FRONT IS EXPECTED TO MOVE THROUGH LATE
SATURDAY AFTERNOON INTO SATURDAY NIGHT BRINGING A GOOD CHANCE OF
SHOWERS AND STORMS TO THE REGION. ITS A LITTLE TOO EARLY TO
DETERMINE IF THERE WOULD BE A SEVERE WEATHER THREAT FOR SATURDAY
EVENING. THE FRONT AND TROUGH SHOULD PUSH EAST OF THE FORECAST
AREA BY LATE SUNDAY MORNING BUT CYCLONIC FLOW ACROSS THE REGION
COULD PRODUCE A FEW RAIN SHOWERS ACROSS THE FORECAST
AREA...ESPECIALLY ACROSS NORTHERN WISCONSIN. HIGH TEMPERATURES ARE
EXPECTED TO COOL BACK INTO THE UPPER 60S TO LOWER 70S IN THE
WAKE OF THE FRONT SUNDAY. HIGH PRESSURE LOOKS TO RETURN BY
MONDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 608 AM CDT TUE AUG 18 2015
LEADING AREA OF SHOWERS ADVANCING EAST ACROSS THE REGION THIS
MORNING. FOR THE MOST PART...THESE ARE OCCURRING WITH VFR
CONDITIONS...BUT UNDER THE HEAVIER ACTIVITY IT QUICKLY GOES DOWN
TO IFR. THE 18.09Z HRRR SEEMS TO HAVE A GOOD HANDLE ON THESE
LEADING SHOWERS AND EXPECT THEM TO REMAIN OVER THE AREA THROUGH
THE MIDDLE OF THE MORNING BEFORE WEAKENING AS THE MAIN FORCING
SHIFTS BACK TO THE WEST AHEAD OF THE MAIN SHORT WAVE TROUGH. THE
MAJORITY OF THE HI-RES MODELS SUGGEST THE MAIN LINE OF CONVECTION
WILL COME IN DURING THE MIDDLE OF THE AFTERNOON BUT THE 18.00Z HI-
RES ARW IS A TOUCH FASTER SO WILL HONOR THIS FASTER TIMING WITH A
VCTS FOR BOTH SITES AND THEN GO CATEGORICAL THUNDERSTORMS FOR THE
LATE AFTERNOON INTO THE EARLY EVENING WITH MVFR/IFR CONDITIONS.
THE DRY SLOT SHOULD THEN WORK OVER THE AREA AND PUSH MOST OF THE
RAIN TO THE NORTH BY THE MIDDLE/LATE EVENING HOURS. NOT SURE WHAT
THE CEILINGS WILL DO IN THE DRY SLOT BUT PLAN TO STAY PESSIMISTIC
AND KEEP THEM DOWN IN THE IFR RANGE. WILL ALSO HOLD ONTO A VCSH AS
SOME OF THE MESO MODELS SHOW SOME SHOWERS OCCASIONALLY COMING
THROUGH UNTIL WELL INTO THE OVERNIGHT HOURS.
&&
.HYDROLOGY...THROUGH WEDNESDAY
ISSUED AT 401 AM CDT TUE AUG 18 2015
WIDESPREAD RAINFALL AMOUNTS OF 1 TO 1.3 INCHES ARE EXPECTED FROM
TODAY THROUGH TONIGHT. BRIEF HEAVY RAINFALL IS POSSIBLE AT TIMES
BUT GIVEN 1 HOUR FLASH FLOOD GUIDANCE RANGING FROM 1.5 TO 2.7
INCHES ALONG WITH ANTECEDENT CONDITIONS...NOT ANTICIPATING THE
NEED FOR ANY HYDROLOGIC HEADLINES.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...04
HYDROLOGY...WETENKAMP
AREA FORECAST DISCUSSION
NWS NEW YORK NY
210 PM EDT TUE AUG 18 2015
.SYNOPSIS...
THE REGION REMAINS IN BETWEEN HIGH PRESSURE OVER THE CANADIAN
MARITIMES AND A COLD FRONT SLOWLY ADVANCING TO THE EAST FROM THE
MIDWEST THROUGH THURSDAY NIGHT. THIS FRONT THEN SLOWLY CROSSES
THE TRI- STATE FRIDAY AND FRIDAY NIGHT. THE FRONT STALLS OUT JUST
TO THE EAST AND SOUTH OF THE AREA...AND WEAKENS... AS HIGH
PRESSURE SLOWLY BUILDS IN FROM THE NORTHEAST THROUGH THE WEEKEND.
ANOTHER COLD FRONT APPROACHES FROM THE WEST ON MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
VERY WARM AND HUMID AIRMASS REMAINS OVER THE REGION WITH SFC TEMPS
IN THE UPPER 80S TO LOW 90S AND SFC DEWPOINTS GENERALLY IN THE 60S
TO NEAR 70. AS A RESULT...MU CAPE VALUES FROM 0-10 KM RANGE FROM
1500-2000 J/KG.
12Z NAM HAS BACKED OFF ON SHRA/TSRA OVER THE AREA THIS
AFTERNOON...BUT THE LATEST HRRR KEEPS SCT SHRA/TSRA ACROSS
INTERIOR PORTIONS OF SOUTHERN CT. WITH AFTERNOON SEA BREEZES
DEVELOPING AND POSSIBLE OUTFLOW BOUNDARIES FROM ANY DEVELOPING
STORMS UPSTREAM...WILL KEEP CHANCE POPS IN THOSE AREAS.
THE HEAT INDEX THIS AFTERNOON WILL TOP OFF IN THE LOW 90S ACROSS
MUCH OF THE CWA...AND INTO THE MID 90S FOR NE NJ AND POSSIBLY FOR
PARTS OF NYC.
THERE IS A MODERATE RISK OF RIP CURRENTS FORECAST FOR THE OCEAN
BEACHES TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
ANY LINGERING SHOWERS...MOST LIKELY CONFINED TO NORTH OF THE
CITY...SHOULD END BY MIDNIGHT AS THE ATMOSPHERE STABILIZES. WINDS
BACK A LITTLE MORE TOWARDS SSE...MAINTAINING PLENTY OF LOW LEVEL
MOISTURE. NOT SO SURE WE SEE STRATUS WITH WATER TEMPS SO
WARM...AND WOULD HAVE LIKE TO SEEN THE LOW LEVEL MOISTURE PROGGED
DEEPER TO PUT IT INTO THE GRIDS...BUT WILL AT LEAST KEEP IN PATCHY
FOG FOR THE SUBURBS LATE AT NIGHT. THAT SAID...SOME STRATUS IS NOT
OUT OF THE QUESTION.
WITH WINDS CONTINUING TO BACK A LITTLE MORE ACROSS THE CWA AND
MOISTURE WELL AHEAD OF A COLD FRONT OVER THE GREAT LAKES SHIFTING
CLOSER...THE BEST MOISTURE CONVERGENCE AND CHANCE OF SHOWERS/TSTMS
ENDS UP BEING MOSTLY WEST OF THE HUDSON DURING WEDNESDAY. STORM
MOTION WILL BE SLOW ONCE AGAIN...SO LOCALLY HEAVY DOWNPOURS WILL BE
POSSIBLE. HIGHS TEMP FORECAST IS SLIGHTLY WARMER THAN A MAV/NAM
MOS BLEND.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
NORTHERN STREAM RIDGING SLOWLY EXITS TO THE NORTHEAST WEDNESDAY
NIGHT AND THURSDAY. SUBSIDENCE FROM THE RIDGE WILL HELP TO LIMIT
POPS TO SLIGHT CHANCE WEDNESDAY NIGHT...AND AT MOST CHANCE ON
THURSDAY. INSTABILITY IN THE WEDNESDAY NIGHT-THURSDAY TIME FRAME IS
VERY WEAK...IF NOT NONE-EXISTENT BASED ON MODEL (AT MOST A FEW
HUNDRED J/KG OF CAPE AND SHOWALTERS GENERALLY ABOVE 3)...SO HAVE
LIMITED MENTION OF THUNDER TO ONLY THOSE AREAS WITH CHANCE POPS (FAR
NW ZONES THURSDAY)...AND THEN CAPPED THE PROBABILITY OF THUNDER TO
SLIGHT CHANCE. GENERALLY EXPECT ANY CONVECTION TO BE OF THE MORE
MISS THAN HIT VARIETY WEDNESDAY NIGHT AND THURSDAY...WITH MOST AREAS
TO THE EAST OF NYC SEEING LITTLE IF ANY PRECIPITATION DURING THIS
TIME FRAME.
FOR LOWS WEDNESDAY NIGHT A BLEND OF ECS/MET/MAV GUIDANCE AND NAM 2-
METER TEMPERATURES WAS USED...WITH VALUES FORECAST TO BE AROUND 5
DEGREES ABOVE NORMAL. A BLEND OF MAV/MET GUIDANCE...MIXING DOWN FROM
975-875 HPA PER BUFKIT SOUNDINGS...AND NAM 2-METER TEMPERATURES WAS
USED FOR HIGHS ON THURSDAY...WITH READINGS EXPECTED TO BE WITHIN A
FEW DEGREES OF EITHER SIDE OF NORMAL.
A NORTHERN STREAM TROUGH LIFTS TO THE N THEN NE THURSDAY NIGHT INTO
FRIDAY EVENING...WITH ITS ASSOCIATED SURFACE COLD FRONT PASSING
THROUGH JUST AHEAD OF IT. SHOULD HAVE SUFFICIENT FORCING MAINLY OVER
WESTERN ZONES TO WARRANT LIKELY POPS THURSDAY NIGHT THERE...WITH
CHANCE POPS OR LESS FARTHER EAST...THEN LIKELY POPS THROUGHOUT ON
FRIDAY...EXCEPT OVER FAR SE ZONES WHERE LIMITED TO CHANCE DUE TO THE
SLOW EASTWARD PROGRESSION OF THE SYSTEM AND THAT THE BEST FORCING IS
LIFTING AWAY FROM THIS AREA.
THE FACT THAT THE BEST FORCING IS LIFTING AWAY FROM THE AREA THE
ENTIRE TIME IS OF SOME CONCERN...AND IS THE REASON WHY POPS WERE NOT
RAISED TO CATEGORICAL. DEPENDING ON EXACTLY HOW THINGS PLAY
OUT...THERE IS SOME POTENTIAL THAT EVEN LIKELY POPS COULD BE
OVERDONE. PROBABILITY OF THUNDER WAS CAPPED AGAIN AT CHANCE DUE TO
CONTINUED LIMITED INSTABILITY IN THE LOW LEVELS. GIVEN THE
OVERALL TREND...HAVE CONTINUED TO MENTION LOCALLY HEAVY RAIN
THURSDAY NIGHT/FRIDAY IN AREAS WITH LIKELY POPS. REFER TO THE
HYDROLOGY SECTION OF THE AFD FOR POTENTIAL QPF AND ANY IMPACTS.
THE WEATHER COULD THEN REMAIN UNSETTLED FROM FRIDAY NIGHT-MONDAY
WITH THE FRONT STALLING OUT NEARBY AND MULTIPLE SHORTWAVES PASSING
OVER THE AREA IN SW FLOW ALOFT. FOR NOW HAVE CHANCE POPS FRIDAY
NIGHT AND SATURDAY WHEN THE COLD FRONT IS AT ITS CLOSEST...THEN
SLIGHT CHANCE POPS SATURDAY NIGHT-MONDAY WITH TWO EXCEPTIONS. THE
FIRST IS SUNDAY WHERE THERE ARE CHANCE POPS OVER THE NW 1/2 OF THE
CWA AS CONVECTION COULD BE DIURNALLY ENHANCED...THEN OVER THE NW 1/3
OF THE AREA ON MONDAY AHEAD OF AN ADVANCING CUTOFF LOW AND
ASSOCIATED TROUGH FORECAST TO MOVE INTO THE GREAT LAKES ON MONDAY.
FOR TEMPERATURES THURSDAY NIGHT-MONDAY A BLEND OF
MEX/MEN/EKD/ECE/ECM/WPC GUIDANCE WAS USED...WITH NAM 2-METER
TEMPERATURES MIXED IN AS WELL FOR THURSDAY NIGHT. LOWS ARE FORECAST
TO REMAIN ABOVE NORMAL IN THIS TIME FRAME WITH HIGHS NEAR TO
SLIGHTLY ABOVE NORMAL.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
ISOLATED SHOWERS AND A POSSIBLE THUNDERSTORM WELL NORTH AND WEST
OF NYC TERMINALS THIS AFTERNOON...PARTICULARLY NEAR KSWF.
OTHERWISE MAINLY VFR IS POSSIBLE WITH ANY LOWER CATEGORIES
RESULTING FROM NIGHTTIME COASTAL PATCHY FOG/LOW STRATUS TONIGHT.
BOTH NAM/GFS GUIDANCE SUGGEST IFR POSSIBLE IN CIGS AND VSBY FOR 6
HOUR PERIOD AFTER 07Z. WILL TREND FORECAST DOWNWARD AS A RESULT. S
FLOW 10-15KT THIS AFTERNOON. G20KT POSSIBLE KLGA. WINDS
DIMINISHING TONIGHT.
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: MODERATE CONFIDENCE IN FORECAST. TIMING
AMENDMENTS POSSIBLE OVERNIGHT IN CIGS/VSBY.
KLGA FCSTER COMMENTS: MODERATE CONFIDENCE IN FORECAST. TIMING
AMENDMENTS POSSIBLE OVERNIGHT IN CIGS/VSBY.
KEWR FCSTER COMMENTS: MODERATE CONFIDENCE IN FORECAST. TIMING
AMENDMENTS POSSIBLE OVERNIGHT IN CIGS/VSBY.
KTEB FCSTER COMMENTS: MODERATE CONFIDENCE IN FORECAST. TIMING
AMENDMENTS POSSIBLE OVERNIGHT IN CIGS/VSBY.
KHPN FCSTER COMMENTS: MODERATE CONFIDENCE IN FORECAST. TIMING
AMENDMENTS POSSIBLE OVERNIGHT IN CIGS/VSBY.
KISP FCSTER COMMENTS: MODERATE CONFIDENCE IN FORECAST. TIMING
AMENDMENTS POSSIBLE OVERNIGHT IN CIGS/VSBY.
.OUTLOOK FOR 18Z WEDNESDAY THROUGH SATURDAY...
.18Z WED...ISOLD-SCT AFTN SHRA/TSTM POSSIBLE MAINLY FROM CITY
TERMINALS ON N/W. S-SW WINDS G15-20KT. MVFR OR LOWER POSSIBLE.
.WED NIGHT-THU...MVFR OR LOWER POSSIBLE WITH A LOW CHC OF SHRA.
RELATIVELY HIGHER CHC THU NEAR CITY TERMINALS AND N/W.
.THU NIGHT-FRI NIGHT...MVFR OR LOWER POSSIBLE IN SHRA/TSTMS.
.SAT AND SUN...MVFR POSSIBLE WITH A CHANCE OF SHRA/TSTMS.
&&
.MARINE...
PREVAILING WINDS AND SEAS SHOULD REMAIN BELOW SCA CRITERIA
THROUGH WEDNESDAY...BUT A FEW GUSTS TO 25 KT WILL BE POSSIBLE NEAR
THE NY HARBOR ENTRANCE LATE THIS AFTERNOON/EARLY EVENING.
A RELAXED PRESSURE GRADIENT OVER THE REGION WILL KEEP WINDS AT 10 KT
OR LESS WEDNESDAY NIGHT THROUGH SATURDAY. SEAS ON THE COASTAL OCEAN
WATERS SHOULD BE 3 FT OR LESS AND ON THE NON-OCEAN WATERS 1 FT OR
LESS IN THIS TIME FRAME AS A RESULT.
&&
.HYDROLOGY...
ALTHOUGH SHOWER/THUNDERSTORM COVERAGE IS EXPECTED TO BE
RELATIVELY SPARSE TODAY...ANYTHING THAT FORMS WILL LIKELY REMAIN
NEARLY STATIONARY OR MOVE VERY SLOWLY...WITH POTENTIAL TO DUMP A
QUICK ISOLATED 1-2 INCHES OF RAIN. LOCALIZED FLASH FLOODING MAINLY
FOR URBAN AREAS IS POSSIBLE...BUT AGAIN...COVERAGE AND OVERALL
CHANCES OF RAINFALL ARE TOO LOW FOR CONSIDERATION OF A WATCH.
FOR WEDNESDAY...SCATTERED HEAVY SHOWERS AND THUNDERSTORMS MAY
CAUSE MAINLY MINOR URBAN FLOODING.
NO SIGNIFICANT WIDESPREAD PRECIPITATION IS EXPECTED
WEDNESDAY NIGHT AND THURSDAY.
FOR NOW FORECASTING 2/10 TO AROUND 1 INCH OF RAIN THURSDAY NIGHT
AND FRIDAY...WITH HIGHEST AMOUNTS OVER NW ZONES AND LOWEST AMOUNTS
OVER FAR E ZONES. WITH STORM MOTION FORECAST TO BE 5 KT OR
LESS...AND PRECIPITABLE WATERS FORECAST ON AVERAGE TO BE BETWEEN
1.5-2 INCHES THURSDAY NIGHT AND FRIDAY (WITH QUITE A BIT OF
DISCREPANCY BETWEEN INDIVIDUAL MODELS WITH THE NAM GOING BELOW 1.5
INCHES AND THE GFS ABOVE 2 INCHES)...THERE IS THE POTENTIAL FOR
ANY STRONGER STORM TO PRODUCE LOCALLY HEAVY RAINFALL. SINCE STORMS
ARE FORECAST TO BE SLOW MOVING...THERE IS THE POTENTIAL FOR
LOCALIZED MINOR URBAN/POOR DRAINAGE FLOODING.
IF PRECIPITABLE WATERS END UP BEING TOWARDS THE HIGHER END OF THE
RANGE...ESPECIALLY IF THE GFS ENDS UP BEING CORRECT...THEN THERE
WOULD BE THE POTENTIAL FOR LOCALIZED FLASH FLOODING AS
WELL...ESPECIALLY IN URBAN AREAS. CONFIDENCE IN WIDESPREAD FLASH
FLOODING CURRENTLY NOT HIGH ENOUGH TO MENTION IN THE HWO...WITH
LARGE DIFFERENCES IN FORECAST PRECIPITABLE WATERS BEING THE
LIMITING FACTOR.
WHILE THE MAIN THREAT FOR LOCALLY HEAVY RAINFALL IS THURSDAY NIGHT
AND FRIDAY...IT IS POSSIBLE THE THREAT COULD LINGER INTO FRIDAY
NIGHT DEPENDING ON EXACTLY HOW FAST THE COLD FRONT SLIDES TO THE
EAST.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JC/MALOIT
NEAR TERM...MPS
SHORT TERM...JC
LONG TERM...MALOIT
AVIATION...IRD
MARINE...JC/MALOIT
HYDROLOGY...JC/MALOIT
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
707 PM EDT TUE AUG 18 2015
.SYNOPSIS...
A MOIST FLOW CIRCULATING AROUND OFFSHORE HIGH PRESSURE WILL
PERSIST THROUGH MUCH OF THE WEEK. SCATTERED TO NUMEROUS SHOWERS
AND THUNDERSTORMS WILL OCCUR.
&&
.NEAR TERM /UNTIL 7 AM WEDNESDAY MORNING/...
THE SOUTHERLY FLOW CIRCULATING AROUND OFFSHORE HIGH PRESSURE HAS
RESULTED IN HIGH MOISTURE IN THE FORECAST AREA. PRECIPITABLE
WATER HAS INCREASED TO JUST OVER 2 INCHES. THE MOISTURE AND
HEATING HAS HELPED CAUSE SCATTERED SHOWERS AND THUNDERSTORMS. WEAK
LIFT AHEAD OF A WEAK MID-LEVEL SHORTWAVE TROUGH MAY RESULT IN MORE
WIDESPREAD COVERAGE LATER THIS EVENING. THE HRRR SHOWED
CONSIDERABLE COVERAGE ESPECIALLY IN THE CSRA AND SOUTH MIDLANDS
DURING THE 800 PM TO 1000 PM TIME FRAME. BELIEVE CLOUDINESS AND
SHOWERS WILL CONTINUE TO LIMIT INSTABILITY. THE SEVERE
THUNDERSTORM CHANCE IS LOW. SOME OF THE THUNDERSTORMS WILL HAVE
HEAVY DOWNPOURS BECAUSE OF THE HIGH PRECIPITABLE WATER. A STORM
MOTION NEAR 15 KNOTS SHOULD HELP KEEP RAIN FROM BECOMING EXCESSIVE
UNLESS TRAINING HAPPENS TO DEVELOP. CLOUDINESS FAVORS THE WARMER
TEMPERATURE GUIDANCE TONIGHT. FORECASTED LOWS MAINLY IN THE MIDDLE
70S.
&&
.SHORT TERM /7 AM WEDNESDAY MORNING THROUGH THURSDAY/...
A MOIST LOW-LEVEL SOUTHERLY FLOW CIRCULATING AROUND OFFSHORE
HIGH PRESSURE AND A SERIES OF MID-LEVEL SHORTWAVE TROUGHS IN A
FLAT FLOW WILL KEEP A THREAT OF SHOWERS AND THUNDERSTORMS ACROSS
THE REGION. PRECIPITABLE WATER WILL REMAIN HIGH WITH VALUES MAINLY
JUST ABOVE 2 INCHES. HEAVY DOWNPOURS MAY OCCUR WITH SOME OF THE
THUNDERSTORMS. USED THE GUIDANCE CONSENSUS FOR THE HIGH
TEMPERATURE FORECAST. USED THE WARMER LOW TEMPERATURE GUIDANCE
BECAUSE OF THE HIGH MOISTURE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
THE GFS AND ECMWF DISPLAY A DIFFUSE FRONT STALLED NEAR THE
FORECAST AREA EARLY IN THE MEDIUM-RANGE PERIOD. THE MODELS DISPLAY
ANOTHER FRONT LATE IN THE PERIOD. THE MODELS HAVE UPPER RIDGING
FRIDAY AND SATURDAY...WITH TROUGHING DURING THE REST OF THE
PERIOD. THE PATTERN SUPPORTS A CONTINUED CHANCE OF SHOWERS AND
THUNDERSTORMS. THE GFS ENSEMBLE MEAN PLUS GFS...ECMWF...AND EKD
MOS SUPPORT POPS OF MAINLY 20 TO 30 PERCENT. ABOVE NORMAL HIGH
TEMPERATURES SHOULD BE ASSOCIATED WITH THE UPPER RIDGING EARLY IN
THE PERIOD. THE REST OF THE PERIOD WILL LIKELY HAVE NEAR NORMAL
TEMPERATURES.
&&
.AVIATION /23Z TUESDAY THROUGH SUNDAY/...
SCATTERED SHOWERS HAVE DEVELOPED EARLY THIS AFTERNOON WITH DEEP
MOISTURE ACROSS THE AREA AND WEAK TO MODERATE INSTABILITY. THE
THREAT OF SHOWERS AND STORMS WILL CONTINUE THROUGH THIS EVENING
AND INTO TONIGHT WITH RESTRICTIONS POSSIBLE IN CONVECTION. HAVE
ADDED A TEMPO GROUP FROM 18Z-23Z TO ACCOUNT FOR SHOWERS AND
STORMS THAT AFFECT THE TERMINALS. WINDS WILL CONTINUE OUT OF THE
SOUTH THROUGH THIS EVENING AT 5 TO 10 KNOTS. MODELS SHOW POTENTIAL
FOR RESTRICTIONS EARLY WEDNESDAY MORNING ALTHOUGH A 25 TO 30 KNOT
LOW LEVEL JET SHOULD HELP LIMIT FOG DEVELOPMENT. CONFIDENCE IS TOO
LOW TO INCLUDE AT THIS TIME.
EXTENDED AVIATION OUTLOOK...A MOIST SOUTHERLY FLOW WILL CONTINUE
THROUGH THURSDAY. THERE WILL BE SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS. STRATUS AND FOG MAY OCCUR DURING THE EARLY MORNING
HOURS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
153 PM EDT TUE AUG 18 2015
.SYNOPSIS...
A MOIST FLOW CIRCULATING AROUND OFFSHORE HIGH PRESSURE WILL
PERSIST THROUGH MUCH OF THE WEEK. SCATTERED TO NUMEROUS SHOWERS
AND THUNDERSTORMS WILL OCCUR.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE SOUTHERLY FLOW CIRCULATING AROUND OFFSHORE HIGH PRESSURE HAS
RESULTED IN HIGH MOISTURE IN THE FORECAST AREA. PRECIPITABLE
WATER HAS INCREASED TO JUST OVER 2 INCHES. THE MOISTURE AND
HEATING HAS HELPED CAUSE SCATTERED SHOWERS AND THUNDERSTORMS EARLY
THIS AFTERNOON. WEAK LIFT AHEAD OF A WEAK MID-LEVEL SHORTWAVE
TROUGH MAY RESULT IN MORE WIDESPREAD COVERAGE LATE THIS AFTERNOON
INTO THE EVENING. THE HRRR SHOWED CONSIDERABLE COVERAGE ESPECIALLY
IN THE CSRA AND SOUTH MIDLANDS DURING THE 600 PM TO 1000 PM TIME
FRAME. BELIEVE CLOUDINESS AND SHOWERS WILL CONTINUE TO LIMIT
INSTABILITY. EARLY AFTERNOON SURFACE-BASED LI/S WERE -4 TO -5 WITH
A NEAR MOIST ADIABATIC LAPSE RATE. THE SEVERE THUNDERSTORM CHANCE
IS LOW. SOME OF THE THUNDERSTORMS WILL HAVE HEAVY DOWNPOURS
BECAUSE OF THE HIGH PRECIPITABLE WATER. A STORM MOTION NEAR 15
KNOTS SHOULD HELP KEEP RAIN FROM BECOMING EXCESSIVE UNLESS
TRAINING HAPPENS TO DEVELOP. CLOUDINESS FAVORS THE WARMER
TEMPERATURE GUIDANCE TONIGHT. FORECASTED LOWS MAINLY IN THE MIDDLE
70S.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
A MOIST LOW-LEVEL SOUTHERLY FLOW CIRCULATING AROUND OFFSHORE
HIGH PRESSURE AND A SERIES OF MID-LEVEL SHORTWAVE TROUGHS IN A
FLAT FLOW WILL KEEP A THREAT OF SHOWERS AND THUNDERSTORMS ACROSS
THE REGION. PRECIPITABLE WATER WILL REMAIN HIGH WITH VALUES MAINLY
JUST ABOVE 2 INCHES. HEAVY DOWNPOURS MAY OCCUR WITH SOME OF THE
THUNDERSTORMS. USED THE GUIDANCE CONSENSUS FOR THE HIGH
TEMPERATURE FORECAST. USED THE WARMER LOW TEMPERATURE GUIDANCE
BECAUSE OF THE HIGH MOISTURE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE GFS AND ECMWF DISPLAY A DIFFUSE FRONT STALLED NEAR THE
FORECAST AREA EARLY IN THE MEDIUM-RANGE PERIOD. THE MODELS DISPLAY
ANOTHER FRONT LATE IN THE PERIOD. THE MODELS HAVE UPPER RIDGING
FRIDAY AND SATURDAY...WITH TROUGHING DURING THE REST OF THE
PERIOD. THE PATTERN SUPPORTS A CONTINUED CHANCE OF SHOWERS AND
THUNDERSTORMS. THE GFS ENSEMBLE MEAN PLUS GFS...ECMWF...AND EKD
MOS SUPPORT POPS OF MAINLY 20 TO 30 PERCENT. ABOVE NORMAL HIGH
TEMPERATURES SHOULD BE ASSOCIATED WITH THE UPPER RIDGING EARLY IN
THE PERIOD. THE REST OF THE PERIOD WILL LIKELY HAVE NEAR NORMAL
TEMPERATURES.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
SCATTERED SHOWERS HAVE DEVELOPED EARLY THIS AFTERNOON WITH DEEP
MOISTURE ACROSS THE AREA AND WEAK TO MODERATE INSTABILITY. THE
THREAT OF SHOWERS AND STORMS WILL CONTINUE THROUGH THIS EVENING
AND INTO TONIGHT WITH RESTRICTIONS POSSIBLE IN CONVECTION. HAVE
ADDED A TEMPO GROUP FROM 18Z-23Z TO ACCOUNT FOR SHOWERS AND
STORMS THAT AFFECT THE TERMINALS. WINDS WILL CONTINUE OUT OF THE
SOUTH THROUGH THIS EVENING AT 5 TO 10 KNOTS. MODELS SHOW POTENTIAL
FOR RESTRICTIONS EARLY WEDNESDAY MORNING ALTHOUGH A 25 TO 30 KNOT
LOW LEVEL JET SHOULD HELP LIMIT FOG DEVELOPMENT. CONFIDENCE IS TOO
LOW TO INCLUDE AT THIS TIME.
EXTENDED AVIATION OUTLOOK...A MOIST SOUTHERLY FLOW WILL CONTINUE
THROUGH THURSDAY. THERE WILL BE SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS. STRATUS AND FOG MAY OCCUR DURING THE EARLY MORNING
HOURS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
104 PM CDT TUE AUG 18 2015
.UPDATE...
ISSUED AT 100 PM CDT TUE AUG 18 2015
HAVE CANCELED THE FLASH FLOOD WATCH AS THE THREAT HAS ENDED. WILL
CONTINUE TO MONITOR THE SEVERE WEATHER THREAT THROUGH THE
AFTERNOON. DRY SLOT CONTINUES TO PROGRESS EAST INTO THE AREA AND
SHOULD BE THROUGH THE FORECAST AREA BY 4-5 PM. GREATEST
INSTABILITIES ARE SET UP TO THE EAST AND LIKELY WILL HAVE STRONGER
STORMS DEVELOP EAST OF THE AREA SOON. STILL CAN NOT DISCOUNT A
TRAILING LINE DEVELOPING BY MID AFTERNOON THAT WOULD PROGRESS
QUICKLY EAST ALONG THE LEADING EDGE OF THE DRY SLOT.
PREVIOUSLY UPDATED AT 1136 AM
EXPECT THE THREAT FOR HEAVY RAINFALL TO CONTINUE TO DIMINISH INTO
THIS AFTERNOON AS THE MID LEVEL DRY SLOT OVERSPREADS THE AREA.
PLAN IS TO DROP THE FLASH FLOOD WATCH SOMETIME EARLY AFTERNOON IF
TRENDS PERSIST. ANY STORM REDEVELOPMENT THIS AFTERNOON WILL HAVE
MUCH MORE PROGRESSIVE STORM MOTIONS THAT WILL LIMIT THE HEAVY RAIN
THREAT. GIVEN THE GOOD DYNAMICS ASSOCIATED WITH THIS UPPER SYSTEM
AND ATTENDANT SHEAR...THE SEVERE WEATHER THREAT SHOULD INCREASE
INTO THIS AFTERNOON AND CONTINUE THROUGH EARLY EVENING. SFC
INSTABILITY STILL IN QUESTION DUE TO LINGERING CLOUD COVER THROUGH
SYSTEM CLIMATOLOGY WOULD SUGGEST AN HOUR OF SUN WILL BE SUFFICIENT
AND THIS IS LIKELY IN SOME AREAS. A TORNADO THREAT WOULD INCREASE SHOULD
SFC INSTABILITY BECOME REALIZED.
.SHORT TERM /TODAY/...
ISSUED AT 411 AM CDT TUE AUG 18 2015
SHOULD BE A FAIRLY ACTIVE DAY TODAY AS AN UPPER TROUGH OVER THE
NORTHERN PLAINS DEEPENS AND DEVELOPS A CLOSED LOW AS IT MOVES INTO
MN WEDNESDAY MORNING. THERE APPEARS TO BE SEVERAL VORT MAXES OVER
THE PLAINS ASSOCIATED WITH THIS TROUGH WHICH WILL LIKELY SWEEP INTO
NORTHWEST AND NORTH CENTRAL IOWA TODAY. AT THE SURFACE...LOW
PRESSURE OVER NORTH CENTRAL KANSAS IS FORECAST TO LIFT NORTHEAST
INTO WESTERN THEN NORTHWEST IOWA BY LATE AFTERNOON BEFORE MOVING
INTO SOUTH CENTRAL MINNESOTA TONIGHT. A WARM FRONT WILL SHIFT
ACROSS CENTRAL IOWA LATER THIS MORNING INTO THE AFTERNOON BRINGING
THE FIRST ROUND OF PRECIPITATION TO CENTRAL IOWA. SHEAR THIS
MORNING IS NOT OVERLY IMPRESSIVE BUT WILL INCREASE AND DEEPEN WITH
TIME. CAPE VALUES INCREASE THIS MORNING THEN MODELS DIMINISH CAPE
THIS AFTERNOON BEFORE BRIEFLY INCREASING IT AGAIN LATE AFTERNOON
INTO THE EVENING ACROSS THE SOUTHWEST WITH THE PASSAGE OF A COLD
FRONT AS THE SURFACE LOW SHIFTS INTO MN. QC FORCING IS PARTICULARLY
IMPRESSIVE THIS MORNING ESPECIALLY OVER THE NORTH.
PWATS ACROSS THE NORTHWEST INTO NORTH CENTRAL APPROACH 2 INCHES AND
THIS IS OVER LOCATIONS THAT GOT QUITE A BIT OF RAINFALL IN THE
RECENT PAST. THE POTENTIAL FOR HEAVY RAINFALL COMBINED WITH ONE
HOUR FLASH FLOOD GUIDANCE OF 1.6 INCHES OR SO HAS PROMPTED THE
ISSUANCE OF A FLASH FLOOD WATCH ACROSS MUCH OF NORTHWEST INTO NORTH
CENTRAL IOWA FOR TODAY THOUGH I DO EXPECT THE HEAVIEST RAINFALL
FROM MID TO LATE MORNING INTO THE EARLY AFTERNOON.
FURTHER SOUTH WHERE THE BETTER INSTABILITY WILL RESIDE WILL BE A
CONDITIONAL POTENTIAL FOR SEVERE WEATHER FROM MID AFTERNOON INTO
EARLY EVENING WITH THE FRONTAL PASSAGE. THERE IS A FAIR AMOUNT OF
UNCERTAINTY AS TO WHAT THE EXTENT OF THE MORNING CONVECTION WILL BE
AND HOW MUCH WE WILL DESTABILIZE LATER TODAY AS MANY OF THE HI-RES
MODELS DRIBBLE CONVECTION ACROSS US FOR MUCH OF THE DAY BUT THEY DO
IN FACT ALL SUGGEST A SECOND ROUND OF CONVECTION IN THE MID
AFTERNOON THROUGH EARLY TO MID EVENING. AT PRESENT THE HRRR SEEMS
TO HAVE A DECENT HANDLE ON THE PRECIP THOUGH ITS A LITTLE TOO HEAVY
ON THE NORTHWARD EXTENT. THE WRF IS CAPTURING THE SOUTHERN PRECIP
AREA A LITTLE BETTER SO I TRIED TO GO WITH A BLEND OF THOSE TWO
MODELS. THE 00Z NAMDNG ALSO HAD A DECENT HANDLE ON PRECIP BUT THE
06Z RUN IS MISSING THE EXPANDING PRECIP ACROSS THE SOUTHWEST. I
HELD TEMPS DOWN A DEGREE OR TWO WITH ESPECIALLY SOUTH WITH THE
EXPECTED CLOUD COVER AND PRECIP. AS FOR POPS...I WENT FAIRLY HIGH
POPS FOR TODAY. IT SHOULD NOT BE RAINING ALL DAY BUT THERE WILL BE
A FEW ROUNDS OF PRECIP AND THE SCATTERED NATURE OF THE STORMS WILL
MAKE IT VERY DIFFICULT TO PIN DOWN TIME AND LOCATION.
.LONG TERM /TONIGHT THROUGH MONDAY/...
ISSUED AT 411 AM CDT TUE AUG 18 2015
FORECAST CHALLENGE EARLY ON IS WHERE OUR LOW WILL BE AT THE START OF
THE LONG TERM FCST PERIOD. MODELS SOMEWHAT SCATTERED WITH PLACEMENT
OF THE LOW AT 00Z WED. THE 00Z TUE EURO/GEM/UKMET ESSENTIALLY THE
MIDDLE PATH. THE 00Z TUE GFS IS NOW A FAST OUTLIER...AND THE 00Z
TUE NAM IS A SLIGHTLY SLOW OUTLIER THAN THE MIDDLE PATH MODELS.
AVAILABLE BAROCLINICITY AND RUN-TO-RUN INCREASINGLY ANOMALOUS
UPSTREAM 500MB SHORTWAVE AND -4 STD DEV SFC LOW SUGGEST THE
SLOWER...MORE ROBUST PATH MAY BE MORE REASONABLE TO FOLLOW. THUS
HAVE GONE WITH A BLEND OF THE NAM/EURO/GEM/UKMET. THIS BLEND
PLACES THE LOW IN NW IOWA AT 00Z WED. AT 00Z WED...THE BEST SLUG
OF FORCING WILL LIKELY BE EXITING OUR CWA AND THERE WILL BE THE
ATTENDANT COLD FRONT DROPPING DOWN ALONG OUR WESTERN COUNTIES INTO
MISSOURI.
SVR THREAT...0-6 KM MUCAPE VALUES MARGINAL AT 1000-1200 J/KG. 0-1 KM
HELICITY DECENT AS IT APPROACHES 200 M2/S2. LCL HEIGHTS ARE
SUFFICIENTLY LOW. GIVEN CLIMATOLOGY...STORM MODE MAY EVOLVE TO
LINEAR/BOWING OVERNIGHT. DCAPE VALUES EXCEED 1000 J/KG. NAM PICKING
UP ON PWATS UPWARDS OF 2 INCHES WITH THIS BOUNDARY PASSAGE...SO A
BRIEF HEAVY DOWNPOUR POSSIBLE. ADDITIONALLY...NAM PLACES RIGHT
ENTRANCE REGION OF 100KT JET STREAK IN TARGETED AREA.
HOWEVER...CONFIDENCE NOT THE GREATEST DUE TO LACK OF MODEL
CONSISTENCY AND THE FACT RAIN/CLOUDS THROUGHOUT THE DAY WILL
HINDER DESTABILIZATION. IF STORMS DO GO WITH THE COLD
FRONT...TORNADOES/DAMAGING WINDS LIKELY THE PRIMARY THREATS.
BY 09-12Z WED...BOUNDARY SHOULD BE WELL EAST OF DMX CWA. STRONG
W/NW CAA WILL BE IMMEDIATELY USHERED INTO IOWA AS 850MB TEMPS
SHOULD BE NEAR 8C ON OUR WESTERN CWA EDGE AND 11C ON OUR EASTERN
EDGE. WEDNESDAY AFTERNOON...LOW PROGGD TO DEEPEN TO MID 990MB
RANGE OVER NW WI...WHICH IS VERY ATYPICAL FOR THIS TIME OF YEAR.
GEFS ENSEMBLES SHOW THIS IS NEARING -4 TO -5 STD DEV. PRESSURE
GRADIENT NOT AS TIGHT IN IA AS IT WILL BE IN MN/WESTERN WI.
NONETHELESS...AROUND 3MB/100 KM...DEPENDING ON MODEL PREFERENCE.
FCST SOUNDINGS STILL SHOW AROUND 40 KTS TO THE TOP OF THE MIXED
LAYER. SO AM EXPECTING SFC WINDS IN THE 15 TO 25 MPH RANGE WITH
GUSTS NEARING 35 MPH...ESPECIALLY IN OUR NORTH. PAST SEVERAL MODEL
RUNS HAVE BEEN SUGGESTING ST/SC DECK WITH THE DEFORMATION ZONE
LINGERING ACROSS NORTHERN IA. THUS HAVE KEPT SLIGHT POPS WITH
MINIMAL QPF GOING THROUGH WED EVE. AT THE VERY LEAST...MAX TEMPS
WILL BE HELD DOWN DUE TO THE CLOUD COVER. WENT LOW 60S NORTH...BUT
THIS MAY NEED TO BE KNOCKED DOWN A FEW DEGREES IF ST DECK HOLDS.
THURSDAY INTO SATURDAY...SFC HIGH PRESSURE WILL PASS FROM THE OZARKS
INTO THE OHIO VALLEY REGION. THIS HIGH WILL BE STRONG ENOUGH TO KEEP
DMX CWA DRY THU AND FRI. TEMPS HAVE CERTAINLY TRENDING UPWARDS FOR
FRIDAY AND SATURDAY. THUS HAVE GONE A FEW DEGREES ABOVE GUIDANCE TO
ADD VALUE TO TEMPERATURE FCST.
SINCE LAST FRI...MODELS HAVE BEEN PLACING IA IN RETURN FLOW BY THE
WEEKEND. 00Z TUE LONG RANGE MODELS CONTINUE THIS...KEEPING THE GULF
WIDE OPEN WITH A 35 KT LLJ PRIMED TO TRANSPORT GULF MOISTURE INTO
IOWA. THIS SETUP WILL INCREASE TEMPS BACK INTO THE 80S AND BRING A
RETURN OF POPS FOR THE WEEKEND.
SUNDAY INTO EARLY NEXT WEEK...MODELS IN SURPRISINGLY GREAT
AGREEMENT...PLUS SHOWING RUN-TO-RUN CONSISTENCY GOOD WITH BRINGING A
STRONG SFC HIGH TOWARDS IOWA. AS CONFIDENCE/CONSISTENCY
INCREASING...TEMPS HAVE BEEN TRENDING DOWNWARD WITH CAA EXPECTED
AHEAD OF THIS HIGH. MAY NEED TO LOWER TEMPERATURES EVEN FURTHER IF
THIS SETUP HOLDS.
&&
.AVIATION...18/18Z
ISSUED AT 1251 PM CDT TUE AUG 18 2015
SCATTERED SHOWERS AND THUNDERSTORMS WILL MOVE THROUGH THIS
AFTERNOON AND WILL HAVE ATTENDANT CIG LOWERINGS TO MVFR TO
POSSIBLY LIFR AT TIMES. A PERIOD OF VFR IS POSSIBLE MOST LOCATIONS
FOLLOWING BEFORE IFR CIGS MOVE INTO NORTHERN IOWA OVERNIGHT. ALL
AREAS MAY LOWER TO MVFR TO IFR OVERNIGHT THEN CIGS GRADUALLY RISE
ON WEDNESDAY. WINDS BECOME SOUTHWEST TO WEST LATE AFTERNOON AND
EVENING THEN BECOMING GUSTY LATE.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...FAB
LONG TERM...KOTENBERG
AVIATION...DONAVON
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1251 PM CDT TUE AUG 18 2015
.UPDATE...
ISSUED AT 1136 AM CDT TUE AUG 18 2015
EXPECT THE THREAT FOR HEAVY RAINFALL TO CONTINUE TO DIMINISH INTO
THIS AFTERNOON AS THE MID LEVEL DRY SLOT OVERSPREADS THE AREA.
PLAN IS TO DROP THE FLASH FLOOD WATCH SOMETIME EARLY AFTERNOON IF
TRENDS PERSIST. ANY STORM REDEVELOPMENT THIS AFTERNOON WILL HAVE
MUCH MORE PROGRESSIVE STORM MOTIONS THAT WILL LIMIT THE HEAVY RAIN
THREAT. GIVEN THE GOOD DYNAMICS ASSOCIATED WITH THIS UPPER SYSTEM
AND ATTENDANT SHEAR...THE SEVERE WEATHER THREAT SHOULD INCREASE
INTO THIS AFTERNOON AND CONTINUE THROUGH EARLY EVENING. SFC
INSTABILITY STILL IN QUESTION DUE TO LINGERING CLOUD COVER THROUGH
SYSTEM CLIMATOLOGY WOULD SUGGEST AN HOUR OF SUN WILL BE SUFFICIENT
AND THIS IS LIKELY IN SOME AREAS. A TORNADO THREAT WOULD INCREASE SHOULD
SFC INSTABILITY BECOME REALIZED.
&&
.SHORT TERM /TODAY/...
ISSUED AT 411 AM CDT TUE AUG 18 2015
SHOULD BE A FAIRLY ACTIVE DAY TODAY AS AN UPPER TROUGH OVER THE
NORTHERN PLAINS DEEPENS AND DEVELOPS A CLOSED LOW AS IT MOVES INTO
MN WEDNESDAY MORNING. THERE APPEARS TO BE SEVERAL VORT MAXES OVER
THE PLAINS ASSOCIATED WITH THIS TROUGH WHICH WILL LIKELY SWEEP INTO
NORTHWEST AND NORTH CENTRAL IOWA TODAY. AT THE SURFACE...LOW
PRESSURE OVER NORTH CENTRAL KANSAS IS FORECAST TO LIFT NORTHEAST
INTO WESTERN THEN NORTHWEST IOWA BY LATE AFTERNOON BEFORE MOVING
INTO SOUTH CENTRAL MINNESOTA TONIGHT. A WARM FRONT WILL SHIFT
ACROSS CENTRAL IOWA LATER THIS MORNING INTO THE AFTERNOON BRINGING
THE FIRST ROUND OF PRECIPITATION TO CENTRAL IOWA. SHEAR THIS
MORNING IS NOT OVERLY IMPRESSIVE BUT WILL INCREASE AND DEEPEN WITH
TIME. CAPE VALUES INCREASE THIS MORNING THEN MODELS DIMINISH CAPE
THIS AFTERNOON BEFORE BRIEFLY INCREASING IT AGAIN LATE AFTERNOON
INTO THE EVENING ACROSS THE SOUTHWEST WITH THE PASSAGE OF A COLD
FRONT AS THE SURFACE LOW SHIFTS INTO MN. QC FORCING IS PARTICULARLY
IMPRESSIVE THIS MORNING ESPECIALLY OVER THE NORTH.
PWATS ACROSS THE NORTHWEST INTO NORTH CENTRAL APPROACH 2 INCHES AND
THIS IS OVER LOCATIONS THAT GOT QUITE A BIT OF RAINFALL IN THE
RECENT PAST. THE POTENTIAL FOR HEAVY RAINFALL COMBINED WITH ONE
HOUR FLASH FLOOD GUIDANCE OF 1.6 INCHES OR SO HAS PROMPTED THE
ISSUANCE OF A FLASH FLOOD WATCH ACROSS MUCH OF NORTHWEST INTO NORTH
CENTRAL IOWA FOR TODAY THOUGH I DO EXPECT THE HEAVIEST RAINFALL
FROM MID TO LATE MORNING INTO THE EARLY AFTERNOON.
FURTHER SOUTH WHERE THE BETTER INSTABILITY WILL RESIDE WILL BE A
CONDITIONAL POTENTIAL FOR SEVERE WEATHER FROM MID AFTERNOON INTO
EARLY EVENING WITH THE FRONTAL PASSAGE. THERE IS A FAIR AMOUNT OF
UNCERTAINTY AS TO WHAT THE EXTENT OF THE MORNING CONVECTION WILL BE
AND HOW MUCH WE WILL DESTABILIZE LATER TODAY AS MANY OF THE HI-RES
MODELS DRIBBLE CONVECTION ACROSS US FOR MUCH OF THE DAY BUT THEY DO
IN FACT ALL SUGGEST A SECOND ROUND OF CONVECTION IN THE MID
AFTERNOON THROUGH EARLY TO MID EVENING. AT PRESENT THE HRRR SEEMS
TO HAVE A DECENT HANDLE ON THE PRECIP THOUGH ITS A LITTLE TOO HEAVY
ON THE NORTHWARD EXTENT. THE WRF IS CAPTURING THE SOUTHERN PRECIP
AREA A LITTLE BETTER SO I TRIED TO GO WITH A BLEND OF THOSE TWO
MODELS. THE 00Z NAMDNG ALSO HAD A DECENT HANDLE ON PRECIP BUT THE
06Z RUN IS MISSING THE EXPANDING PRECIP ACROSS THE SOUTHWEST. I
HELD TEMPS DOWN A DEGREE OR TWO WITH ESPECIALLY SOUTH WITH THE
EXPECTED CLOUD COVER AND PRECIP. AS FOR POPS...I WENT FAIRLY HIGH
POPS FOR TODAY. IT SHOULD NOT BE RAINING ALL DAY BUT THERE WILL BE
A FEW ROUNDS OF PRECIP AND THE SCATTERED NATURE OF THE STORMS WILL
MAKE IT VERY DIFFICULT TO PIN DOWN TIME AND LOCATION.
.LONG TERM /TONIGHT THROUGH MONDAY/...
ISSUED AT 411 AM CDT TUE AUG 18 2015
FORECAST CHALLENGE EARLY ON IS WHERE OUR LOW WILL BE AT THE START OF
THE LONG TERM FCST PERIOD. MODELS SOMEWHAT SCATTERED WITH PLACEMENT
OF THE LOW AT 00Z WED. THE 00Z TUE EURO/GEM/UKMET ESSENTIALLY THE
MIDDLE PATH. THE 00Z TUE GFS IS NOW A FAST OUTLIER...AND THE 00Z
TUE NAM IS A SLIGHTLY SLOW OUTLIER THAN THE MIDDLE PATH MODELS.
AVAILABLE BAROCLINICITY AND RUN-TO-RUN INCREASINGLY ANOMALOUS
UPSTREAM 500MB SHORTWAVE AND -4 STD DEV SFC LOW SUGGEST THE
SLOWER...MORE ROBUST PATH MAY BE MORE REASONABLE TO FOLLOW. THUS
HAVE GONE WITH A BLEND OF THE NAM/EURO/GEM/UKMET. THIS BLEND
PLACES THE LOW IN NW IOWA AT 00Z WED. AT 00Z WED...THE BEST SLUG
OF FORCING WILL LIKELY BE EXITING OUR CWA AND THERE WILL BE THE
ATTENDANT COLD FRONT DROPPING DOWN ALONG OUR WESTERN COUNTIES INTO
MISSOURI.
SVR THREAT...0-6 KM MUCAPE VALUES MARGINAL AT 1000-1200 J/KG. 0-1 KM
HELICITY DECENT AS IT APPROACHES 200 M2/S2. LCL HEIGHTS ARE
SUFFICIENTLY LOW. GIVEN CLIMATOLOGY...STORM MODE MAY EVOLVE TO
LINEAR/BOWING OVERNIGHT. DCAPE VALUES EXCEED 1000 J/KG. NAM PICKING
UP ON PWATS UPWARDS OF 2 INCHES WITH THIS BOUNDARY PASSAGE...SO A
BRIEF HEAVY DOWNPOUR POSSIBLE. ADDITIONALLY...NAM PLACES RIGHT
ENTRANCE REGION OF 100KT JET STREAK IN TARGETED AREA.
HOWEVER...CONFIDENCE NOT THE GREATEST DUE TO LACK OF MODEL
CONSISTENCY AND THE FACT RAIN/CLOUDS THROUGHOUT THE DAY WILL
HINDER DESTABILIZATION. IF STORMS DO GO WITH THE COLD
FRONT...TORNADOES/DAMAGING WINDS LIKELY THE PRIMARY THREATS.
BY 09-12Z WED...BOUNDARY SHOULD BE WELL EAST OF DMX CWA. STRONG
W/NW CAA WILL BE IMMEDIATELY USHERED INTO IOWA AS 850MB TEMPS
SHOULD BE NEAR 8C ON OUR WESTERN CWA EDGE AND 11C ON OUR EASTERN
EDGE. WEDNESDAY AFTERNOON...LOW PROGGD TO DEEPEN TO MID 990MB
RANGE OVER NW WI...WHICH IS VERY ATYPICAL FOR THIS TIME OF YEAR.
GEFS ENSEMBLES SHOW THIS IS NEARING -4 TO -5 STD DEV. PRESSURE
GRADIENT NOT AS TIGHT IN IA AS IT WILL BE IN MN/WESTERN WI.
NONETHELESS...AROUND 3MB/100 KM...DEPENDING ON MODEL PREFERENCE.
FCST SOUNDINGS STILL SHOW AROUND 40 KTS TO THE TOP OF THE MIXED
LAYER. SO AM EXPECTING SFC WINDS IN THE 15 TO 25 MPH RANGE WITH
GUSTS NEARING 35 MPH...ESPECIALLY IN OUR NORTH. PAST SEVERAL MODEL
RUNS HAVE BEEN SUGGESTING ST/SC DECK WITH THE DEFORMATION ZONE
LINGERING ACROSS NORTHERN IA. THUS HAVE KEPT SLIGHT POPS WITH
MINIMAL QPF GOING THROUGH WED EVE. AT THE VERY LEAST...MAX TEMPS
WILL BE HELD DOWN DUE TO THE CLOUD COVER. WENT LOW 60S NORTH...BUT
THIS MAY NEED TO BE KNOCKED DOWN A FEW DEGREES IF ST DECK HOLDS.
THURSDAY INTO SATURDAY...SFC HIGH PRESSURE WILL PASS FROM THE OZARKS
INTO THE OHIO VALLEY REGION. THIS HIGH WILL BE STRONG ENOUGH TO KEEP
DMX CWA DRY THU AND FRI. TEMPS HAVE CERTAINLY TRENDING UPWARDS FOR
FRIDAY AND SATURDAY. THUS HAVE GONE A FEW DEGREES ABOVE GUIDANCE TO
ADD VALUE TO TEMPERATURE FCST.
SINCE LAST FRI...MODELS HAVE BEEN PLACING IA IN RETURN FLOW BY THE
WEEKEND. 00Z TUE LONG RANGE MODELS CONTINUE THIS...KEEPING THE GULF
WIDE OPEN WITH A 35 KT LLJ PRIMED TO TRANSPORT GULF MOISTURE INTO
IOWA. THIS SETUP WILL INCREASE TEMPS BACK INTO THE 80S AND BRING A
RETURN OF POPS FOR THE WEEKEND.
SUNDAY INTO EARLY NEXT WEEK...MODELS IN SURPRISINGLY GREAT
AGREEMENT...PLUS SHOWING RUN-TO-RUN CONSISTENCY GOOD WITH BRINGING A
STRONG SFC HIGH TOWARDS IOWA. AS CONFIDENCE/CONSISTENCY
INCREASING...TEMPS HAVE BEEN TRENDING DOWNWARD WITH CAA EXPECTED
AHEAD OF THIS HIGH. MAY NEED TO LOWER TEMPERATURES EVEN FURTHER IF
THIS SETUP HOLDS.
&&
.AVIATION...18/18Z
ISSUED AT 1251 PM CDT TUE AUG 18 2015
SCATTERED SHOWERS AND THUNDERSTORMS WILL MOVE THROUGH THIS
AFTERNOON AND WILL HAVE ATTENDANT CIG LOWERINGS TO MVFR TO
POSSIBLY LIFR AT TIMES. A PERIOD OF VFR IS POSSIBLE MOST LOCATIONS
FOLLOWING BEFORE IFR CIGS MOVE INTO NORTHERN IOWA OVERNIGHT. ALL
AREAS MAY LOWER TO MVFR TO IFR OVERNIGHT THEN CIGS GRADUALLY RISE
ON WEDNESDAY. WINDS BECOME SOUTHWEST TO WEST LATE AFTERNOON AND
EVENING THEN BECOMING GUSTY LATE.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR CALHOUN-
CARROLL-CRAWFORD-EMMET-HANCOCK-HUMBOLDT-KOSSUTH-PALO ALTO-
POCAHONTAS-SAC-WEBSTER-WINNEBAGO-WRIGHT.
&&
$$
UPDATE...DONAVON
SHORT TERM...FAB
LONG TERM...KOTENBERG
AVIATION...DONAVON
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1136 AM CDT TUE AUG 18 2015
.UPDATE...
ISSUED AT 1136 AM CDT TUE AUG 18 2015
EXPECT THE THREAT FOR HEAVY RAINFALL TO CONTINUE TO DIMINISH INTO
THIS AFTERNOON AS THE MID LEVEL DRY SLOT OVERSPREADS THE AREA.
PLAN IS TO DROP THE FLASH FLOOD WATCH SOMETIME EARLY AFTERNOON IF
TRENDS PERSIST. ANY STORM REDEVELOPMENT THIS AFTERNOON WILL HAVE
MUCH MORE PROGRESSIVE STORM MOTIONS THAT WILL LIMIT THE HEAVY RAIN
THREAT. GIVEN THE GOOD DYNAMICS ASSOCIATED WITH THIS UPPER SYSTEM
AND ATTENDANT SHEAR...THE SEVERE WEATHER THREAT SHOULD INCREASE
INTO THIS AFTERNOON AND CONTINUE THROUGH EARLY EVENING. SFC
INSTABILITY STILL IN QUESTION DUE TO LINGERING CLOUD COVER THROUGH
SYSTEM CLIMATOLOGY WOULD SUGGEST AN HOUR OF SUN WILL BE SUFFICIENT
AND THIS IS LIKELY IN SOME AREAS. A TORNADO THREAT WOULD INCREASE SHOULD
SFC INSTABILITY BECOME REALIZED.
&&
.SHORT TERM /TODAY/...
ISSUED AT 411 AM CDT TUE AUG 18 2015
SHOULD BE A FAIRLY ACTIVE DAY TODAY AS AN UPPER TROUGH OVER THE
NORTHERN PLAINS DEEPENS AND DEVELOPS A CLOSED LOW AS IT MOVES INTO
MN WEDNESDAY MORNING. THERE APPEARS TO BE SEVERAL VORT MAXES OVER
THE PLAINS ASSOCIATED WITH THIS TROUGH WHICH WILL LIKELY SWEEP INTO
NORTHWEST AND NORTH CENTRAL IOWA TODAY. AT THE SURFACE...LOW
PRESSURE OVER NORTH CENTRAL KANSAS IS FORECAST TO LIFT NORTHEAST
INTO WESTERN THEN NORTHWEST IOWA BY LATE AFTERNOON BEFORE MOVING
INTO SOUTH CENTRAL MINNESOTA TONIGHT. A WARM FRONT WILL SHIFT
ACROSS CENTRAL IOWA LATER THIS MORNING INTO THE AFTERNOON BRINGING
THE FIRST ROUND OF PRECIPITATION TO CENTRAL IOWA. SHEAR THIS
MORNING IS NOT OVERLY IMPRESSIVE BUT WILL INCREASE AND DEEPEN WITH
TIME. CAPE VALUES INCREASE THIS MORNING THEN MODELS DIMINISH CAPE
THIS AFTERNOON BEFORE BRIEFLY INCREASING IT AGAIN LATE AFTERNOON
INTO THE EVENING ACROSS THE SOUTHWEST WITH THE PASSAGE OF A COLD
FRONT AS THE SURFACE LOW SHIFTS INTO MN. QC FORCING IS PARTICULARLY
IMPRESSIVE THIS MORNING ESPECIALLY OVER THE NORTH.
PWATS ACROSS THE NORTHWEST INTO NORTH CENTRAL APPROACH 2 INCHES AND
THIS IS OVER LOCATIONS THAT GOT QUITE A BIT OF RAINFALL IN THE
RECENT PAST. THE POTENTIAL FOR HEAVY RAINFALL COMBINED WITH ONE
HOUR FLASH FLOOD GUIDANCE OF 1.6 INCHES OR SO HAS PROMPTED THE
ISSUANCE OF A FLASH FLOOD WATCH ACROSS MUCH OF NORTHWEST INTO NORTH
CENTRAL IOWA FOR TODAY THOUGH I DO EXPECT THE HEAVIEST RAINFALL
FROM MID TO LATE MORNING INTO THE EARLY AFTERNOON.
FURTHER SOUTH WHERE THE BETTER INSTABILITY WILL RESIDE WILL BE A
CONDITIONAL POTENTIAL FOR SEVERE WEATHER FROM MID AFTERNOON INTO
EARLY EVENING WITH THE FRONTAL PASSAGE. THERE IS A FAIR AMOUNT OF
UNCERTAINTY AS TO WHAT THE EXTENT OF THE MORNING CONVECTION WILL BE
AND HOW MUCH WE WILL DESTABILIZE LATER TODAY AS MANY OF THE HI-RES
MODELS DRIBBLE CONVECTION ACROSS US FOR MUCH OF THE DAY BUT THEY DO
IN FACT ALL SUGGEST A SECOND ROUND OF CONVECTION IN THE MID
AFTERNOON THROUGH EARLY TO MID EVENING. AT PRESENT THE HRRR SEEMS
TO HAVE A DECENT HANDLE ON THE PRECIP THOUGH ITS A LITTLE TOO HEAVY
ON THE NORTHWARD EXTENT. THE WRF IS CAPTURING THE SOUTHERN PRECIP
AREA A LITTLE BETTER SO I TRIED TO GO WITH A BLEND OF THOSE TWO
MODELS. THE 00Z NAMDNG ALSO HAD A DECENT HANDLE ON PRECIP BUT THE
06Z RUN IS MISSING THE EXPANDING PRECIP ACROSS THE SOUTHWEST. I
HELD TEMPS DOWN A DEGREE OR TWO WITH ESPECIALLY SOUTH WITH THE
EXPECTED CLOUD COVER AND PRECIP. AS FOR POPS...I WENT FAIRLY HIGH
POPS FOR TODAY. IT SHOULD NOT BE RAINING ALL DAY BUT THERE WILL BE
A FEW ROUNDS OF PRECIP AND THE SCATTERED NATURE OF THE STORMS WILL
MAKE IT VERY DIFFICULT TO PIN DOWN TIME AND LOCATION.
.LONG TERM /TONIGHT THROUGH MONDAY/...
ISSUED AT 411 AM CDT TUE AUG 18 2015
FORECAST CHALLENGE EARLY ON IS WHERE OUR LOW WILL BE AT THE START OF
THE LONG TERM FCST PERIOD. MODELS SOMEWHAT SCATTERED WITH PLACEMENT
OF THE LOW AT 00Z WED. THE 00Z TUE EURO/GEM/UKMET ESSENTIALLY THE
MIDDLE PATH. THE 00Z TUE GFS IS NOW A FAST OUTLIER...AND THE 00Z
TUE NAM IS A SLIGHTLY SLOW OUTLIER THAN THE MIDDLE PATH MODELS.
AVAILABLE BAROCLINICITY AND RUN-TO-RUN INCREASINGLY ANOMALOUS
UPSTREAM 500MB SHORTWAVE AND -4 STD DEV SFC LOW SUGGEST THE
SLOWER...MORE ROBUST PATH MAY BE MORE REASONABLE TO FOLLOW. THUS
HAVE GONE WITH A BLEND OF THE NAM/EURO/GEM/UKMET. THIS BLEND
PLACES THE LOW IN NW IOWA AT 00Z WED. AT 00Z WED...THE BEST SLUG
OF FORCING WILL LIKELY BE EXITING OUR CWA AND THERE WILL BE THE
ATTENDANT COLD FRONT DROPPING DOWN ALONG OUR WESTERN COUNTIES INTO
MISSOURI.
SVR THREAT...0-6 KM MUCAPE VALUES MARGINAL AT 1000-1200 J/KG. 0-1 KM
HELICITY DECENT AS IT APPROACHES 200 M2/S2. LCL HEIGHTS ARE
SUFFICIENTLY LOW. GIVEN CLIMATOLOGY...STORM MODE MAY EVOLVE TO
LINEAR/BOWING OVERNIGHT. DCAPE VALUES EXCEED 1000 J/KG. NAM PICKING
UP ON PWATS UPWARDS OF 2 INCHES WITH THIS BOUNDARY PASSAGE...SO A
BRIEF HEAVY DOWNPOUR POSSIBLE. ADDITIONALLY...NAM PLACES RIGHT
ENTRANCE REGION OF 100KT JET STREAK IN TARGETED AREA.
HOWEVER...CONFIDENCE NOT THE GREATEST DUE TO LACK OF MODEL
CONSISTENCY AND THE FACT RAIN/CLOUDS THROUGHOUT THE DAY WILL
HINDER DESTABILIZATION. IF STORMS DO GO WITH THE COLD
FRONT...TORNADOES/DAMAGING WINDS LIKELY THE PRIMARY THREATS.
BY 09-12Z WED...BOUNDARY SHOULD BE WELL EAST OF DMX CWA. STRONG
W/NW CAA WILL BE IMMEDIATELY USHERED INTO IOWA AS 850MB TEMPS
SHOULD BE NEAR 8C ON OUR WESTERN CWA EDGE AND 11C ON OUR EASTERN
EDGE. WEDNESDAY AFTERNOON...LOW PROGGD TO DEEPEN TO MID 990MB
RANGE OVER NW WI...WHICH IS VERY ATYPICAL FOR THIS TIME OF YEAR.
GEFS ENSEMBLES SHOW THIS IS NEARING -4 TO -5 STD DEV. PRESSURE
GRADIENT NOT AS TIGHT IN IA AS IT WILL BE IN MN/WESTERN WI.
NONETHELESS...AROUND 3MB/100 KM...DEPENDING ON MODEL PREFERENCE.
FCST SOUNDINGS STILL SHOW AROUND 40 KTS TO THE TOP OF THE MIXED
LAYER. SO AM EXPECTING SFC WINDS IN THE 15 TO 25 MPH RANGE WITH
GUSTS NEARING 35 MPH...ESPECIALLY IN OUR NORTH. PAST SEVERAL MODEL
RUNS HAVE BEEN SUGGESTING ST/SC DECK WITH THE DEFORMATION ZONE
LINGERING ACROSS NORTHERN IA. THUS HAVE KEPT SLIGHT POPS WITH
MINIMAL QPF GOING THROUGH WED EVE. AT THE VERY LEAST...MAX TEMPS
WILL BE HELD DOWN DUE TO THE CLOUD COVER. WENT LOW 60S NORTH...BUT
THIS MAY NEED TO BE KNOCKED DOWN A FEW DEGREES IF ST DECK HOLDS.
THURSDAY INTO SATURDAY...SFC HIGH PRESSURE WILL PASS FROM THE OZARKS
INTO THE OHIO VALLEY REGION. THIS HIGH WILL BE STRONG ENOUGH TO KEEP
DMX CWA DRY THU AND FRI. TEMPS HAVE CERTAINLY TRENDING UPWARDS FOR
FRIDAY AND SATURDAY. THUS HAVE GONE A FEW DEGREES ABOVE GUIDANCE TO
ADD VALUE TO TEMPERATURE FCST.
SINCE LAST FRI...MODELS HAVE BEEN PLACING IA IN RETURN FLOW BY THE
WEEKEND. 00Z TUE LONG RANGE MODELS CONTINUE THIS...KEEPING THE GULF
WIDE OPEN WITH A 35 KT LLJ PRIMED TO TRANSPORT GULF MOISTURE INTO
IOWA. THIS SETUP WILL INCREASE TEMPS BACK INTO THE 80S AND BRING A
RETURN OF POPS FOR THE WEEKEND.
SUNDAY INTO EARLY NEXT WEEK...MODELS IN SURPRISINGLY GREAT
AGREEMENT...PLUS SHOWING RUN-TO-RUN CONSISTENCY GOOD WITH BRINGING A
STRONG SFC HIGH TOWARDS IOWA. AS CONFIDENCE/CONSISTENCY
INCREASING...TEMPS HAVE BEEN TRENDING DOWNWARD WITH CAA EXPECTED
AHEAD OF THIS HIGH. MAY NEED TO LOWER TEMPERATURES EVEN FURTHER IF
THIS SETUP HOLDS.
&&
.AVIATION...18/12Z
ISSUED AT 700 AM CDT MON AUG 17 2015
SHOWERS AND THUNDERSTORMS WILL CONTINUE TO EXPAND ACROSS THE WEST
HALF OF CENTRAL IOWA. LOCALLY HEAVY RAINFALL AND LOW CIGS/VSBYS
WILL BE THE MAIN THREAT THIS MORNING. MID TO LATE AFTN THROUGH MID
EVENING AS A SURFACE LOW SHIFTS INTO MN ADDITIONAL STORMS WILL
DEVELOP ALONG A COLD FRONT. IFR CONDITIONS WILL PERSIST THROUGH 06Z
BEFORE IMPROVING AS THE FRONT PUSHES OUT OF THE TAF LOCATIONS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR CALHOUN-
CARROLL-CRAWFORD-EMMET-HANCOCK-HUMBOLDT-KOSSUTH-PALO ALTO-
POCAHONTAS-SAC-WEBSTER-WINNEBAGO-WRIGHT.
&&
$$
UPDATE...DONAVON
SHORT TERM...FAB
LONG TERM...KOTENBERG
AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS TOPEKA KS
335 PM CDT TUE AUG 18 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 335 PM CDT TUE AUG 18 2015
19Z WATER VAPOR SHOWS A CLOSED UPPER LOW OVER SD WHILE SURFACE OBS
PLACE THE LOW OVER NORTHWEST IA/SOUTHWEST MN BORDER. A STRONG COLD
FRONT EXTENDED SOUTH FROM THE SURFACE LOW THROUGH SOUTHEAST NEB TO
JUST WEST OF SLN. VISIBLE SATELLITE HAS SHOWN SOME BREAKS IN THE
CLOUDS AHEAD OF THE FRONT WHICH HAS ALLOWED TEMPS TO WARM INTO THE
LOWER 80S. THIS WOULD SUPPORT SURFACE BASED CAPE VALUES AROUND
1000J/KG WHILE 0-6 KM SHEAR INCREASES TO AROUND 45 KTS. SO THE
POTENTIAL FOR SEVERE STORMS REMAINS IN PLACE. MODELS SHOW AREA ALONG
AND SOUTH OF I-70 AS THE PLACES THAT SHOULD SEE THE BETTER
INSTABILITY. THEREFORE THINK THIS MAY BE WHERE STRONG TO SEVERE
STORMS DEVELOP THIS AFTERNOON, IF THEY STRENGTHEN. SINCE SURFACE
WINDS HAVE VEERED TO THE SOUTHWEST AHEAD OF THE FRONT, THE POTENTIAL
FOR TORNADOES APPEARS TO REMAIN FAIRLY SMALL. THE RAP AND HRRR,
WHICH HAVE SHOWN A BETTER TIMING FOR THE FRONT, TAKE THE BOUNDARY
EAST OF THE FORECAST AREA BETWEEN 8 AND 9 PM. THE RISK FOR SEVERE
WEATHER SHOULD DIMINISH QUICKLY BEHIND THE FRONT AS COOLER MORE
STABLE AIR COMES IN.
ONCE THE FRONT PASSES EAST, THINK THE REST OF TONIGHT WILL BE FAIRLY
UNEVENTFUL. THERE HAVE BEEN SOME LOWER CLOUDS ACROSS WESTERN NEB
MIST OF THE DAY BUT THE MODELS TEND TO KEEP THE LOWER CLOUDS TO THE
NORTH OVERNIGHT. THEREFORE WITH COLD AIR ADVECTION AND MOST LIKELY
PARTLY CLOUDY SKIES, LOWS IN THE MID AND UPPER 50S LOOKS ON TARGET.
BY LATE TONIGHT AND THROUGH THE MORNING WEDNESDAY, MODELS SWING A
DECENT VORT MAX THROUGH THE BASE OF THE UPPER TROUGH PASSING THROUGH
EASTERN KS. THERE IS NO SIGN OF LOW LEVEL MOISTURE ADVECTION OVER
THE COLD FRONT, BUT THERE IS AN INDICATION OF A SATURATED AIRMASS
ACROSS EAST CENTRAL KS WITH GOOD FRONTOGENESIS AS THE WAVE PASSES
OVERHEAD. BECAUSE OF THIS HAVE CONTINUED WITH SOME CHANCE POPS FOR
RAIN MAINLY OVER EAST CENTRAL KS. THERE SHOULD BE MORE DRY AIR OVER
NORTH CENTRAL AND NORTHEAST KS THAT WILL LIMIT PRECIP CHANCES. THE
COLD AIR ADVECTION WEAKENS THROUGH THE DAY WEDNESDAY, BUT THERE MAY
BE SOME CLOUDS LINGER. THEREFORE HIGHS ARE FORECAST TO TOP OUT IN
THE LOWER AND MID 70S. THIS IS ABOUT 15 DEGREES BELOW NORMAL FOR
THIS TIME OF YEAR.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 335 PM CDT TUE AUG 18 2015
LOWER LEVEL WINDS BACK TO THE WEST WEDNESDAY NIGHT AND THEN
SOUTHWEST INTO THURSDAY NIGHT BRINGING SOME WARMING BACK AND SURFACE
TEMPS SHOULD MODIFY CONSIDERABLY. HAVE KEPT VALUES NEAR TO BELOW
MOS FOR WEDNESDAY NIGHT IN LIGHT WINDS AND CLEAR SKIES. MODELS
TRENDING A BIT COOLER FOR FRIDAY WITH CONTINUED BACKED TO NEAR
SOUTHEAST WITH HIGHS STILL LIKELY CLOSE TO THOSE OF THURSDAY. PRECIP
CHANCES CONTINUE TO LOOK QUITE LOW THROUGH THURSDAY NIGHT. AT LEAST
SOME MOISTURE RETURNS AHEAD OF A WEAK UPPER WAVE FRIDAY...THOUGH
THERE REMAINS TO BE A WIDE DEGREE OF VARIANCE IN BOTH OF THESE
ELEMENTS...WITH A TREND TOWARD LOWER AVAILABLE MOISTURE NOTED. AT
THIS POINT CHANCES FOR ANYTHING MORE THAN ISOLATED PRECIP LOOK LOW.
FOR THE BEGINNING OF THE WEEKEND, RETURN FLOW WILL BE IN PLACE OVER
THE SOUTHERN AND CENTRAL PLAINS AHEAD OF A DEEPENING TROUGH OVER THE
NORTHERN ROCKIES. THIS SYSTEM WILL CONTINUE EASTWARD PROGRESSION
INTO THE DAY SATURDAY AND OVERNIGHT INTO SUNDAY BEFORE IT BECOMES
MORE NEGATIVELY TILTED AND LIFTS THROUGH THE UPPER MISSISSIPPI
VALLEY INTO THE GREAT LAKES REGION BY MONDAY. THIS LARGER SCALE
FEATURE SHOULD BRING ABOUT THE CHANCE OF ELEVATED STORMS FOR
SATURDAY MORNING AS A LLJ SHOULD HELP ENHANCE AN AREA OF ISENTROPIC
LIFT OVER EASTERN KS. INTO THE DAY, SOUNDINGS DO SUGGEST THAT STORM
POTENTIAL MAY BE LIMITED WITH A PRETTY STRONG CAP DEVELOPING OVER
THE REGION. THE BETTER CHANCE FOR THUNDERSTORM REDEVELOPMENT WILL
BE IN THE LATE AFTERNOON INTO THE EARLY EVENING AS SHEAR PROFILES
BECOME A LITTLE MORE ORGANIZED AND WAA INCREASES LOW LEVEL MOISTURE
ALONG WITH INSTABILITY OVER THE REGION. SOME POTENTIAL FOR STRONG
TO SEVERE STORMS COULD EXIST, BUT STILL TOO FAR OUT TO PINPOINT
OVERALL LIKELIHOOD. MODELS SEEM TO BE IN FAIRLY GOOD AGREEMENT FOR
THE MOST PART WITH EASTWARD PROGRESSION OF THE TROUGH. THE GFS
SOLUTION DOES SEEM TO BE THE MORE AGGRESSIVE OF THE SOLUTIONS THOUGH
WITH A DEEPER UPPER LOW AND MORE NORTHERLY PROGRESSION AFTER THE
MONDAY MORNING TIME FRAME. IN THE WAKE OF THIS FALL-LIKE LOOKING
SYSTEM, WILL BE ANOTHER NICE FEW DAYS AS HEIGHTS RISE AND SUBSIDENCE
SETS IN WITH SIGNIFICANT MOISTURE BEING PUSHED SOUTH.
HIGH TEMPS COOL BEHIND THE SYSTEM INTO THE UPPER 70S
AND ONLY CLIMB INTO THE MID 80S BY TUESDAY. LOWS MEANWHILE COULD
FLIRT WITH LOW 50S IN PARTS OF THE AREA BY TUESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1227 PM CDT TUE AUG 18 2015
ANY NEW TS DEVELOPMENT THIS AFTERNOON APPEARS TO BE MORE SCATTED
IN NATURE. SO ONLY HAVE CONFIDENCE TO KEEP A VCTS IN THE
TERMINALS. THINK THE TS CHANCES WILL DIMINISH QUICKLY ONCE THE
FRONT PASSES THROUGH, WHICH IS TIMED BASED ON THE RAP AND HRRR
PROGS. NOTICED THE MVFR COGS UPSTREAM ACROSS WESTERN NEB. FOR NOW
THE MODEL PROGS KEEP ANY CIGS ABOVE 3KFT, BUT WILL NEED TO MONITOR
THIS THROUGH THE EVENING.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...WOLTERS
LONG TERM...65/DRAKE
AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1227 PM CDT TUE AUG 18 2015
.UPDATE...
ISSUED AT 1227 PM CDT TUE AUG 18 2015
OVERALL THE FORECAST SEEMS TO BE UNFOLDING AS EXPECTED. IF
ANYTHING THE COLD FRONT IS A LITTLE MORE PROGRESSIVE THAN EARLIER
PROGGED, BUT THE HRRR AND RAP SEEM TO HAVE A GOOD REPRESENTATION
OF THE FRONT NOW. BECAUSE OF THIS THINK THE NAM IS AN OUTLIER WITH
THE ISOLATED CONVECTION IT TRIES TO DEVELOP AROUND 00Z. CURRENT
CONDITIONS AHEAD OF THE FRONT SHOW SOME WARMING WITH TEMPS NEAR
80 FROM SLN TO MHK. WITH THE INCREASING 0-6KM SHEAR AND SURFACE
BASED CAPE NOW AROUND 1000 J/KG, IT APPEARS AS THOUGH THERE IS A
RISK FOR SEVERE STORMS THROUGH THE AFTERNOON WITH THE COLD FRONT.
LOW LEVEL WINDS VEERED TO THE SOUTHWEST ARE NOT VERY CONDUCIVE FOR
MUCH OR A TORNADO RISK, BUT THERE COULD BE SOME DAMAGING WINDS OR
HAIL WITH THE MORE ORGANIZED STORMS.
UPDATE ISSUED AT 452 AM CDT TUE AUG 18 2015
RECENT OBSERVATIONS (ASOS AND RADAR), AS WELL AS RECENT MODEL HIGH
RES MODEL GUIDANCE HAVE PROMPTED A FORECAST UPDATE EARLY THIS
MORNING. CENTRAL KANSAS HAS SEEN THE DEVELOPMENT OF A STRONG
PRESSURE GRADIENT ON THE NORTH AND NORTHEAST SIDES OF THE INCOMING
CONVECTIVE CLUSTER. THE LOW LEVEL JET HAS STRENGTHENED IN THESE
AREAS AS WELL WITH 40 KTS AT ICT AND INDICATIONS BY MODEL AND
RADAR DATA OF STRONGER WINDS YET JUST NORTH AND NORTHEAST OF THE
CIRCULATION CENTER. IT APPEARS THAT THIS SYSTEM IS UNDERGOING A
DEEPENING OF THE LOW AND IS FORECAST TO CONTINUE DEEPENING AS IT
MOVES NORTHEAST THROUGH THIS MORNING. THIS HAS PROMOTED ENHANCED
WINDS VIA THE STRENGTHENING PRESSURE GRADIENT ALONG WITH SOME
INCREASED MIXING ON THE EDGE OF STRATIFORM PRECIP AND WITH
STRONGER CONVECTIVE AREAS. ONE CONCERN IS THAT AS THIS SYSTEM
MOVES OVER THE FORECAST AREA, LOW LEVEL MIXING MAY INCREASE A BIT
AFTER SUNRISE AND PROVIDE A PERIOD OF ENHANCED SURFACE WIND
SPEEDS DURING THE MORNING HOURS. CONFIDENCE IS NOT HIGH BUT IT
SEEMS PLAUSIBLE. FOR NOW FEEL THAT AN AREA OF 30+ MPH WINDS ARE
LIKELY BUT WOULD NOT BE SURPRISED TO SEE SOME AREAS OF 50+ AND
WILL BE WATCHING IT CLOSELY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 353 AM CDT TUE AUG 18 2015
A VERY COMPLEX AND POTENT STORM SYSTEM...ESPECIALLY FOR MID AUGUST
IN THIS PART OF THE COUNTRY...IS ORGANIZING AND MOVING INTO THE
PLAINS THIS MORNING. NOTABLE FEATURES INCLUDE LEAD SHORT WAVE
TROUGHS APPROACHING LAKE MICHIGAN, SOUTHWEST IOWA, AND ONE OF
PARTICULARLY INTEREST CROSSING OUT OF SOUTHWEST KANSAS EARLY THIS
MORNING. THE MAIN UPPER LEVEL TROUGH ENERGY WAS FOCUSED OVER WESTERN
SOUTH DAKOTA WITH ADDITIONAL ENERGY WELL UPSTREAM IN SOUTHERN
CANADA. EACH OF THESE PIECES OF ENERGY WAS DRIVING CONVECTIVE
CLUSTERS. THE CONVECTIVE COMPLEX OVER SOUTH CENTRAL KANSAS AT 3 AM
HAD A PARTICULARLY TIGHT SPIN TO IT WITH STRONG FOCUSED ASCENT IN
ADVANCE OF THE CIRCULATION AND RATHER STRONG SUBSIDENCE IN ITS WAKE.
ANOTHER WELL-ORGANIZED CONVECTIVE SYSTEM WAS MOVING ACROSS NORTHERN
NEBRASKA WITH SOME OF THE ENERGY APPARENTLY DRIVING MORE ISOLATED
CONVECTION AS FAR SOUTH AS NORTHWEST KANSAS. THIS ALSO SEEMED TO BE
TIED TO THE MAIN UPPER TROUGH AND SURGING COLD FRONT.
IN THE NEAR TERM, EXPECT THE CONVECTIVE COMPLEX OVER SOUTH CENTRAL
KANSAS TO BUILD TOWARD THE EAST AND NORTHEAST THIS MORNING AND
PROVIDE RAIN AND EMBEDDED THUNDERSTORMS TO MUCH OF THE FORECAST AREA
BEFORE NOON. AND INTERESTING FEATURE WITH THIS IS A VERY STRONG
PRESSURE GRADIENT WITH A STRONG MESO LOW CENTERED NORTH OF ELLSWORTH
AND A MESO HIGH UNDER THE CENTER OF THE PRECIPITATION SHIELD. THIS
FEATURE...POTENTIALLY WITH SOME ASSISTANCE FROM ENHANCED DOWNWARD
MOTION ON THE EDGE OF PRECIPITATION...WAS RESULTING IN SOME STRONG
WIND GUSTS OF 30 TO 45 KTS. THESE WINDS WOULD SEEM LIKELY TO
CONTINUE INTO THE ABILENE AND PERHAPS MANHATTAN AREAS WITH
TIME...ALTHOUGH HOW LONG THEY PERSIST AT THIS STRENGTH IS A BIT OF A
QUESTION MARK. OTHER THAN THESE STRONGER WINDS, THIS RAIN AND
EMBEDDED STORMS ARE EXPECTED TO BE RATHER BENIGN, ALTHOUGH WILL WANT
TO KEEP AN EYE ON ANY BOWING SEGMENTS IN THE SOUTHEAST QUADRANT OF
THE SYSTEM AS IT SHIFTS EAST. THIS PRECIPITATION IS LIKELY TO SHIFT
EAST OF THE FORECAST AREA BY EARLY AFTERNOON.
THE AFTERNOON FORECAST REMAINS INTERESTING. EXPECT SUBSIDENCE IN THE
WAKE OF THE MORNING PRECIP AND THIS SHOULD RESULT IN A BREAK IN RAIN
FOR MOST OF THE AREA. QUESTIONS ARISE WHETHER THIS SUBSIDENCE WILL
BE STRONG ENOUGH TO CREATE BREAKS IN THE CLOUDS, AND AT THIS POINT
FEEL THAT CLOUDS WILL LIKELY DOMINATE THE DAY. THERE IS ALSO SOME
CHANCE FOR SCATTERED CONVECTION TO START UP SHORTLY IN THE WAKE OF
THE MORNING ACTIVITY GIVEN ADDITIONAL WEAKER SHORT WAVE ENERGY
INCOMING. THE MAIN SHOW WILL BE ALONG A PRE-FRONTAL TROUGH OR
POSSIBLY THE ACTUAL COLD FRONT THIS AFTERNOON, WITH STORMS LIKELY TO
DEVELOP BY 3 PM. THERE ARE TWO MAIN QUESTIONS AT THIS TIME...1 IS
WHETHER THE STORMS WILL DEVELOP ON THE COLD FRONT OR ON THE PRE-
FRONTAL TROUGH/WIND SHIFT FROM SSE TO SW THAT MOST MODEL GUIDANCE IS
SUGGESTING WILL EXIST...AND THE SECOND QUESTION IS HOW MUCH
INSTABILITY WILL EXIST FOR STORMS TO WORK WITH. WOULD LIKE TO SEE
TEMPERATURES CLIMB INTO THE LOWER 80S FOR SEVERE POTENTIAL TO EXIST,
ALTHOUGH 80 IS NOT A HARD CUTOFF. THIS SEEMS POSSIBLE EVEN WITH
CLOUD COVER GIVEN PERSISTENT SOUTH WIND AND LOW LEVEL MIXING.
ASSUMING THAT TEMPERATURES WARM AND 1000-2000 J/KG OF MLCAPE ARE
PRESENT, THEN SEE POTENTIAL FOR SOME SUPERCELL STRUCTURES AS WELL AS
BOWING SEGMENTS TO DEVELOP GIVEN INCREASING DEEP WIND SHEAR AND
LARGELY UNIDIRECTIONAL SHEAR PROFILES. DAMAGING WINDS WOULD SEEM TO
BE THE PRIMARY HAZARD GIVEN THE WIND PROFILES ALTHOUGH ANY SUPERCELL
STRUCTURES WOULD POINT TO ENHANCED LARGE HAIL POTENTIAL. CAN NOT
COMPLETELY RULE OUT A TORNADO GIVEN MODERATE 0-1 KM WIND SHEAR BUT
THE LOW LEVEL FLOW IS QUITE VEERED AND FAIRLY UNIDIRECTIONAL SO THE
POTENTIAL APPEARS MINIMAL AND PROBABLY CONTINGENT ON A WELL
DEVELOPED SUPERCELL. KEEP IN MIND THAT IT IS ENTIRELY POSSIBLE THAT
THESE AFTERNOON STORMS LACK INSTABILITY AND REMAIN DISORGANIZED AND
SUB-SEVERE...BUT FOR NOW WOULD AT LEAST PLAN ON A FEW STRONG TO
SEVERE STORMS.
STORMS WILL PUSH EAST OF THE FORECAST AREA BY MID EVENING WITH
LINGERING SHOWERS POSSIBLE ESPECIALLY IN EAST CENTRAL KANSAS. THE
COLD FRONT WILL MOVE THROUGH WITH MUCH COOLER TEMPERATURES MOVING IN
ALONG WITH NORTHWEST WINDS. LOWS SHOULD BE IN THE 50S BY SUNRISE ON
WEDNESDAY.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 353 AM CDT TUE AUG 18 2015
BY WEDNESDAY MORNING, POST FRONTAL SHOWERS AND THUNDERSTORMS MAY BE
LINGERING ACROSS FAR EAST CENTRAL KANSAS, QUICKLY EXITING SOUTHEAST
BY LATE MORNING. WHILE THE GFS IS ADVERTISING THIS FEATURE FURTHER
SOUTH COMPARED TO PREVIOUS RUNS, THE NAM, GEM, AND ECMWF ARE STILL
INDICATING AN ADDITIONAL VORT LOBE TO ROTATE THROUGH THE UPPER
TROUGH AXIS DURING THE LATE AFTERNOON PERIOD. SUBSIDENCE WILL ALSO
BE INCREASING FROM THE NORTH SO AREAS ALONG AND SOUTH OF I70 MAY SEE
A MIX OF RAIN SHOWERS OR DRIZZLE AS RIDGING BUILDS IN WEDNESDAY
EVENING. MUCH COOLER HIGHS ARE IN STORE AS THE STEADY COLD ADVECTION
INCREASES FROM THE NORTHWEST WITH GUSTS UP TO 20 MPH AT TIMES. HIGHS
IN THE LOWER TO MIDDLE 70S ARE LIKELY. HIGH PRESSURE INFLUENCE
WEDNESDAY EVENING HELP TO CLEAR SKIES AND QUICKLY COOL OVERNIGHT
LOWS INTO THE MID 50S. THERE IS POTENTIAL FOR PATCHY FOG DEPENDING
ON HOW QUICKLY SKIES CLEAR AND WHERE PRECIP FALLS DURING THE DAY.
SKIES CLEAR AND DRY CONDITIONS RETURN TEMPORARILY AS BROAD TROUGHING
STRETCHES THROUGH MUCH OF THE CONUS. A WEAK EMBEDDED WAVE FROM THE
SOUTHWEST INTERACTS WITH A PLUME OF GULF MOISTURE OVER SOUTHERN
TEXAS, LIFTING NORTHEAST TOWARDS THE CWA ON FRIDAY AFTERNOON AND
EVENING. THE GFS HAS CONTINUED TO BE THE AMPLIFIED SOLUTION WHILE
THE ECMWF AND GEM DEPICT WEAKER FORCING WITH MORE SCATTERED
CONVECTION, FOCUSED FROM EAST CENTRAL KS INTO MO. THERE APPEARS TO
BE A BRIEF BREAK IN PRECIP ON SATURDAY AS SOUTHERLY WINDS BECOME
GUSTY IN RESPONSE TO A DEEPENING SFC LOW OVER THE WESTERN HIGH
PLAINS. ANOTHER STOUT NEGATIVELY TROUGH IS PROGGED TO DIVE SOUTHEAST
TOWARDS THE AREA SATURDAY AFTERNOON INTO EARLY SUNDAY. A FEW STRONG
STORMS MAY BE POSSIBLE WITH ELEVATED INSTABILITY INCREASING THROUGH
THE DAY AND A DECENT WIND PROFILE IN FORECAST SOUNDINGS. AFTER
READINGS NEAR 90 ON SATURDAY, HIGHS STEADILY FALL BACK AGAIN TO NEAR
80 DEGREES ON SUNDAY INTO EARLY NEXT WEEK. STRONG RIDGING CEASES
PRECIP CHANCES THROUGH THE FIRST HALF OF NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1227 PM CDT TUE AUG 18 2015
ANY NEW TS DEVELOPMENT THIS AFTERNOON APPEARS TO BE MORE SCATTED
IN NATURE. SO ONLY HAVE CONFIDENCE TO KEEP A VCTS IN THE
TERMINALS. THINK THE TS CHANCES WILL DIMINISH QUICKLY ONCE THE
FRONT PASSES THROUGH, WHICH IS TIMED BASED ON THE RAP AND HRRR
PROGS. NOTICED THE MVFR COGS UPSTREAM ACROSS WESTERN NEB. FOR NOW
THE MODEL PROGS KEEP ANY CIGS ABOVE 3KFT, BUT WILL NEED TO MONITOR
THIS THROUGH THE EVENING.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
UPDATE...WOLTERS
SHORT TERM...BARJENBRUCH
LONG TERM...BOWEN
AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
317 PM CDT TUE AUG 18 2015
. DISCUSSION... A REPEAT OF TEMPERATURES STRUGGLING TO REACH 90
DEGREES HAS OCCURRED AS THE RESULT OF ANOTHER DAY FILLED WITH
PLENTIFUL CLOUDCOVER AND CONVECTION. A SHORTWAVE IMPULSE...
ORIGINATING IN THE SOUTHWEST GULF OF MEXICO...HAS BEEN AND IS
STILL PASSING OVER THE REGION FROM SW TO NE. THE HRRR HAS DONE AN
OUTSTANDING JOB ON CONVECTIVE INITIATION THIS MORNING AND
CONTINUED GENERAL PRECIP OUTPUT. SO BASED ON THIS MODEL AND
AGREEMENT FROM MEDIUM RANGE MODELS...SHOWERS AND THUNDERSTORMS
SHOULD BEGIN TO TAPER OFF SOMETIME AROUND 00Z TO 02Z. ISOLATED
COASTAL SHOWERS COULD PERSIST OVERNIGHT WITH SOME INLAND INTRUSION
AFTER 09Z.
MODELS INDICATE THAT AN UPPER LEVEL TROUGH WILL DIP DOWN INTO THE
UPPER MISSISSIPPI VALLEY TONIGHT AND SWING ACROSS THE GREAT LAKES
THROUGH THURSDAY. A COLD FRONT ASSOCIATED WITH THIS TROUGH WILL MOVE
SOUTH ACROSS THE COUNTRY WED AND THURS BUT STALL WELL NORTH OF THE
AREA. DESPITE THIS...ABUNDANT MOISTURE WILL CONTINUE TO FLOW IN
TOWARDS THAT BOUNDARY AND ANY UPPER LEVEL HEIGHTS WILL CONTINUE TO
LOWER. THAT COMBINATION WILL BE CONDUCIVE FOR NUMEROUS SHOWERS AND
STORMS THROUGHOUT THE REST OF THIS WEEK. THUS WILL KEEP LIKELY POPS
THROUGH AT LEAST FRIDAY.
A GRADUALLY DRYING OUT WILL TAKE PLACE GOING INTO THE WEEKEND AS THE
UPPER TROUGH TO THE NORTH SHIFTS EAST AND WEAK HIGH PRESSURE TRIES
TO BUILD IN.
MEFFER
&&
.AVIATION...
SCATTERED SHOWERS AND THUNDERSTORMS WILL ONCE AGAIN BE POSSIBLE
ACROSS ALL OF SOUTHEAST LOUISIANA AND SOUTHERN MISSISSIPPI TODAY AND
TOMORROW. HAVE VCTS WORDING IN PLACE THROUGH 00Z FOR ALL OF THE
TERMINALS TO REFLECT THE RISK OF CONVECTION. IF A THUNDERSTORM
THREATENS A TERMINAL...AN HOUR OR LESS OF IFR VISIBILITY
RESTRICTIONS DUE TO HEAVY RAINFALL CAN BE EXPECTED. OUTSIDE OF THE
CONVECTIVE ACTIVITY...A BROKEN CU FIELD RANGING FROM 3500 TO 5000
FEET CAN BE EXPECTED THROUGH THE DAY. AFTER 00Z...THE CONVECTION
SHOULD DISSIPATE AND EXPECT VFR CONDITIONS TO PREVAIL THROUGH AROUND
10Z. AFTER 10Z...SOME LOW STRATOCU RANGING FROM 1500 TO 2500 FEET
SHOULD DEVELOP AROUND THE BASE OF A WEAK ELEVATED INVERSION. EXPECT
THESE MVFR CEILINGS TO PERSIST THROUGH AROUND 15Z BEFORE LIFTING
ABOVE 3000 FEET. SCATTERED SHOWERS WILL ALSO BE POSSIBLE AFTER
12Z...AND HAVE VCSH WORDING IN PLACE TO REFLECT THIS RISK OF DEEP
TROPICAL MOISTURE AND A WEAK TROUGH OF LOWER PRESSURE LINGERS OVER
THE REGION. 32
&&
.MARINE...
MAIN ISSUE FOR MARINERS THROUGH AT LEAST THURSDAY WILL BE
THE DEVELOPMENT OF SCATTERED TO NUMEROUS THUNDERSTORMS...WITH THE
POTENTIAL FOR WINDS GUSTING ABOVE 30 KNOTS. OUTSIDE OF THE
THUNDERSTORM THREAT...GENERAL ONSHORE FLOW FROM THE SOUTH WILL
CONTINUE THROUGH THE END OF THE WORK WEEK. SHOULD BE ENOUGH OF A
GRADIENT TODAY AND WEDNESDAY TO PRODUCE 10-15 KNOT WINDS OVER THE
OPEN WATERS BEFORE RELAXING BELOW 10 KNOTS IN MOST AREAS FOR
THURSDAY THROUGH SATURDAY. AS EAST COAST TROF DEEPENS OVER THE
WEEKEND...OFFSHORE FLOW SHOULD DEVELOP ON SUNDAY. 35
&&
.DECISION SUPPORT...
DSS CODE....GREEN.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...NONE.
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED WATCH/WARNING/ADVISORY
ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE RISK SVR AND/OR DIRECT
TROPICAL THREATS; EVENTS OF NATIONAL SIGNIFICANCE
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 73 86 74 87 / 20 60 40 60
BTR 75 87 75 88 / 20 70 40 60
ASD 78 88 77 88 / 20 70 30 60
MSY 80 89 79 88 / 20 70 30 60
GPT 78 88 79 88 / 20 70 30 60
PQL 78 88 79 88 / 20 60 30 50
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
336 PM EDT TUE AUG 18 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 335 PM EDT TUE AUG 18 2015
WV IMAGERY AND RAP ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
FROM NRN HUDSON BAY INTO THE NRN PLAINS RESULTING IN A WSW FLOW INTO
THE NRN GREAT LAKES. A LINGERNIG AREA OF 700 MB FGEN AND WEAK
WAA/ISENTROPIC LIFT CONTINUES TO SUPPORT A PERSISTENT CLUSTER OF
SHOWERS OVER SCNTRL UPPER MI INTO EARLY AFTERNOON. UPSTREAM A
VIGOROUS SHRTWV ROTATING OVER SD/NE WILL LIFT TOWARD THE UPPER GREAT
LAKES TONIGHT BRINGING SHRA TO UPPER MI MAINLY TONIGHT INTO EARLY
WED. AT THE SFC...A WEAK FRONTAL BOUNDARY EXTENDED FROM CNTRL IA
THROUGH CNTRAL WI INTO CNTRL LWR MI. WITH HIGH PRES OVER NRN
ONTARIO...LIGHT NE WINDS PREVAILED ACROSS THE NRN LAKES TODAY.
TONIGHT...ATTENTION TURNS TO THE DEVELOPING UNSEASONABLY STRONG LOW
PRES SYSTEM MOVING OUT OF THE PLAINS. THE SD/NE SHRTWV WILL SUPPORT
A DEEPENING LOW MOVING INTO SRN MN BY 00Z/WED AND THEN INTO NRN
WI/SW U.P. BY 12Z/WED AS THE CENTRAL PRESSURE LOWERS NEAR 995 MB
APPROACHING RECORD LEVELS FOR THIS TIME OF YEAR. STRONG MOISTURE
TRANSPORT AND 305K-310K ISENTROPIC ASCENT WILL BRING AN AREA OF RAIN
THROUGH UPPER MI TONIGHT...MAINLY AFTER MIDNIGHT. HOWEVER...THIS
TRANSIENT BAND IS EXPECTED TO BRING QPF AMOUNTS OF ONLY 0.25-0.40
INCHES OVER THE CNTRL AND ERN CWA. THE FAR WEST HAS THE POTENTIAL TO
GET HIGHER AMOUNTS (0.5 TO ONE INCH) CLOSER TO THE STRONGEST DEEP
LAYER QVECTOR CONV AND LIFT WHICH WILL REMAIN TO THE WEST OVER NRN MN
AND WRN LAKE SUPERIOR. WITH MODEST MUCAPE VALUES INTO THE 200- 500
J/KG RANGE ONLY ISOLD TSRA ARE EXPECTED.
WEDNESDAY...SHOWERS WILL BE EXITING N AND E WED MORNING AHEAD OF THE
COLD FRONT AND THEN THE DRY SLOT WITH THE SYSTEM WILL MOVE IN FROM
THE SW WED LATE MORNING/AFTERNOON. ALTHOUGH THERE WILL BE STRONG 0-6
KM SHEAR ALONG THE FRONTAL BOUNDARY...AMOUNT OF INSTABILITY (MODELS
PROJECT 300-600 J/KG) REMAINS IN QUESTION AS THERE COULD BE
CONSIDERABLE CLOUD COVER LINGERING OVER THE AREA. BUT IF SUFFICIENT
INSTABILITY DEVELOPS AHEAD/ALONG THE FRONT...THERE COULD BE SOME
STRONG TO POSSIBLY SEVERE STORMS FORMING OVER MAINLY THE CENTRAL AND
ERN CWA IN THE MORNING. AFTER THE DRY SLOT MOVES INTO MAINLY THE
CENTRAL AND ERN CWA EXPECT SHRA TO GENERALLY DISSIPATE IN THE
AFTERNOON. WRAP AROUND PRECIP/MOISTURE WITH SYSTEM COULD MOVE INTO
WRN UPPER MI LATE IN THE DAY. WED LOOKS WINDY OVER CENTRAL AND ERN
UPPER MI WITH S-SW WINDS GUSTING TO 25-30 MPH.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 251 PM EDT TUE AUG 18 2015
THE ANOMALOUS UPPER TROUGH AND SURFACE LOW (AROUND 3-4 SIGMA) WILL
BE CENTERED BETWEEN DULUTH AND ISLE ROYALE AT THE START OF THE LONG
TERM FORECAST. THESE FEATURES WILL BE SLOWLY LIFTING TO THE
NORTHEAST THROUGH THURSDAY...BRINGING THE POTENTIAL FOR RAIN
SHOWERS AND BREEZY CONDITIONS TO THE AREA DURING THAT PERIOD.
STARTING OFF THE PERIOD...THE MID LEVEL DRY SLOT WILL BE OVER THE
CENTRAL AND EASTERN U.P. AND DON/T EXPECT MUCH MORE THAN LOW CLOUDS
FOR THE EVENING. BUT OVER THE WEST...WRAP AROUND MOISTURE WILL LEAD
TO SCATTERED/NUMEROUS SHOWERS WILL BE OCCURRING AND WILL LIKELY SEE
SOME ASSISTANCE FROM TERRAIN ENHANCEMENT WITH THE WEST-NORTHWEST
WINDS BEHIND THE SURFACE TROUGH THAT WILL BE LOCATED OVER THE
CENTRAL U.P. AT 06Z THURSDAY. AS THAT LOW LIFTS TO THE NORTHEAST
OVERNIGHT WEDNESDAY INTO THURSDAY...EXPECT THE SHOWERS TO SHIFT
EASTWARD BEHIND THE TROUGH AND MOVE OVER THE CENTRAL/EASTERN U.P.
ACCUMULATIONS WILL BE LIGHTER THAN OVER THE WEST WITH LESS TERRAIN
INFLUENCE...BUT SHOULD STILL SEE A FEW HUNDREDTHS BY LATE THURSDAY
AFTERNOON. WITH THE UPPER LOW QUICKLY MOVING TO THE NORTH THURSDAY
AFTERNOON INTO THURSDAY NIGHT...SHOULD SEE THE SHOWER COVERAGE
QUICKLY DIMINISH AS DRIER AIR ASSOCIATED WITH A SURFACE RIDGE MOVING
NORTHEAST INTO THE AREA. HAVE FOLLOWED THAT IDEA BOTH WITH THE POPS
AND CLOUD COVER THURSDAY AFTERNOON AND EVENING. IN FACT...SOME OF
THE AREAS NEAR THE WISCONSIN BORDER MAY HAVE THE LOW CLOUDS SCATTER
OUT BY EARLY AFTERNOON. IN ADDITION TO THE RAIN...EXPECT WINDS TO
INCREASE OVER AT LEAST THE WESTERN HALF OF THE CWA ON WEDNESDAY
NIGHT. THE DIFFERENCES IN THE MODELS LEADS TO SOME UNCERTAINTY IN
THE STRENGTH...BUT IT STILL APPEARS THAT GUSTS UP TO 30KTS ARE
POSSIBLE OVER THE KEWEENAW. FOR THE REST OF THE AREA...EXPECT GUSTS
IN THE 20-25KT RANGE ON THURSDAY.
THE HIGH PRESSURE RIDGE WILL BE NEAR THE AREA (FROM A HIGH IN THE
OHIO RIVER VALLEY) THROUGH FRIDAY NIGHT...BUT EXPECT THE GRADIENT
TO TIGHTEN THROUGH THAT PERIOD AS ANOTHER LOW DEVELOPS IN THE
NORTHERN PLAINS. THAT GRADIENT AND PLENTY OF SUNSHINE SHOULD LEAD TO
DECENT MIXING ON FRIDAY (AROUND 800MB)...RAISING TEMPERATURES TO
NORMAL OR SLIGHTLY ABOVE NORMAL VALUES UNDER OCCASIONALLY GUSTY
SOUTHWESTERLY WINDS (17-23KTS). WITH THE UPPER TROUGH AND SURFACE
LOW STILL NEAR THE NORTHERN PLAINS AND MOVING INTO THE UPPER
MISSISSIPPI VALLEY...EXPECT A SIMILAR DAY ON SATURDAY. HAVE REMOVED
THE POPS OVER THE WEST FOR SATURDAY AND WILL KEEP SKIES MOSTLY
SUNNY. SINCE THE TIGHTENING GRADIENT WILL REMAIN IN PLACE AHEAD OF
THE LOW...EXPECT WINDS TO BE A LITTLE GUSTIER THAN FRIDAY (UP TO
25KTS) AND TEMPERATURES TO BE A FEW DEGREES WARMER.
THE UPPER TROUGH FOR THE SECOND HALF OF THE WEEKEND
WILL MOVE THROUGH THE UPPER GREAT LAKES REGION OVERNIGHT SATURDAY
THROUGH SUNDAY EVENING. MEANWHILE...THE SURFACE LOW WILL LIFT
NORTH-NORTHEAST FROM NORTHWEST MINNESOTA TO FAR NORTHERN ONTARIO.
THIS WILL LEAD TO A SHARP COLD FRONT MOVING EAST ACROSS THE AREA ON
SUNDAY. MODELS SEEM TO BE FOCUSING ON LATE SATURDAY NIGHT AND
SUNDAY MORNING FOR THE FRONT TO MOVE THROUGH AND WILL FOCUS THE
HIGHEST POPS DURING THAT PERIOD (LOW LIKELY) AND QUICKLY RAMP
UP/DOWN ON BOTH SIDES. MODELS NOT SHOWING A WHOLE LOT OF INSTABILITY
AHEAD OF THE FRONT (MUCAPE VALUES ONLY UP TO 500 J/KG)...SO THINK
THAT THE THUNDER THREAT WILL BE LIMITED AND WILL CAP AT CHANCES.
THE COLD FRONT WILL USHER IN ANOTHER PERIOD OF BELOW NORMAL
TEMPERATURES FOR THE START OF NEXT WEEK AS HIGH PRESSURE BUILDS
OVER THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 253 PM EDT TUE AUG 18 2015
MAINLY MVFR CIGS ARE EXPECTED AT KSAW AND KCMX WITH CONTINUED MOIST
UPSLOPE E-NE FLOW THIS AFTERNOON. CIGS SHOULD ALSO LOWER AT IWD
TOWARD EVENING AS A STRENGTHENING ESE FLOW AHEAD OF DEEPENING LOW
PRES IN THE PLAINS WL BRING A RETURN OF MORE WDSPRD -RA/MVFR
CONDITIONS IN THE EVENING DROPPING TO IFR/LIFR OVERNIGHT. EXPECT
SLOWLY IMPROVING CONDITIONS BY LATE WED MORNING IN THE WAKE OF THE
FRONT ALONG WITH GUSTY SW WINDS NEAR 25 KTS AT KSAW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 327 PM EDT TUE AUG 18 2015
AS LOW PRES ORGANIZES AND STRENGTHENS OVER THE PLAINS THIS EVENING
...NE WINDS WILL BEGIN TO INCREASE...ESPECIALLY OVER WRN LAKE
SUPERIOR WHERE GUSTS SHOULD REACH 30KT LATE AFTN/EARLY EVENING. MAY
EVEN BE A FEW GALE GUSTS NEAR APOSTLE ISLANDS EARLY EVENING. THIS
LOW WILL BECOME UNSEASONABLY DEEP FOR AUG AS IT LIFTS ACROSS WRN
LAKE SUPERIOR WED AFTERNOON. 20-30KT WINDS ARE EXPECTED OVER MUCH OF
THE LAKE TONIGHT INTO WED. MAY SEE GALE FORCE GUSTS OVER FAR WRN
LAKE SUPERIOR IN THE NE WINDS AHEAD OF THE LOW TONIGHT AND THEN IN
THE WESTERLY WINDS ACROSS WRN AND CENTRAL LAKE SUPERIOR ON THU AS
THE LOW LIFTS N OF THE AREA. WINDS WILL DIMINISH TO UNDER 20KT BY
FRI...AND THEN BEGIN TO INCREASE SOME AGAIN ON SAT AHEAD OF THE NEXT
COLD FRONT MOVING OUT ACROSS THE PLAINS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
328 PM EDT TUE AUG 18 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 327 PM EDT TUE AUG 18 2015
WV IMAGERY AND RAP ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
FROM NRN HUDSON BAY INTO THE NRN PLAINS RESULTING IN A WSW FLOW INTO
THE NRN GREAT LAKES. A LINGERNIG AREA OF 700 MB FGEN AND WEAK
WAA/ISENTROPIC LIFT CONTINUES TO SUPPORT A PERSISTENT CLUSTER OF
SHOWERS OVER SCNTRL UPPER MI INTO EARLY AFTERNOON. UPSTREAM A
VIGOROUS SHRTWV ROTATING OVER SD/NE WILL LIFT TOWARD THE UPPER GREAT
LAKES TONIGHT BRINGING SHRA TO UPPER MI MAINLY TONIGHT INTO EARLY
WED. AT THE SFC...A WEAK FRONTAL BOUNDARY EXTENDED FROM CNTRL IA
THROUGH CNTRAL WI INTO CNTRL LWR MI. WITH HIGH PRES OVER NRN
ONTARIO...LIGHT NE WINDS PREVAILED ACROSS THE NRN LAKES TODAY.
TONIGHT...ATTENTION TURNS TO THE DEVELOPING UNSEASONABLY STRONG LOW
PRES SYSTEM MOVING OUT OF THE PLAINS. THE SD/NE SHRTWV WILL SUPPORT
A DEEPENING LOW MOVING INTO SRN MN BY 00Z/WED AND THEN INTO NRN
WI/SW U.P. BY 12Z/WED AS THE CENTRAL PRESSURE LOWERS NEAR 995/996 MB
APPROACHING RECORD LEVELS FOR THIS TIME OF YEAR. STRONG MOISTURE
TRANSPORT AND 305K-310K ISENTROPIC ASCENT WILL BRING AN AREA OF RAIN
THROUGH UPPER MI TONIGHT...MAINLY AFTER MIDNIGHT. HOWEVER...THIS
TRANSIENT BAND IS EXPECTED TO BRING QPF AMOUNTS OF ONLY 0.25-0.40
INCHES OVER THE CNTRL AND ERN CWA. THE FAR WEST HAS THE POTENTIAL TO
GET HIGHER AMOUNTS (0.5 TO ONE INCH) CLOSER TO THE STRONGEST DEEP
LAYER QVECTOR CONV AND LIFT WHICH WILL REMAIN TO THE WEST OVER NRN
MN AND WRN LAKE SUPERIOR. WITH MODEST MUCAPE VALUES INTO THE 200-
500 J/KG RANGE ONLY ISOLD TSRA ARE EXPECTED.
WEDNESDAY...SHOWERS WILL BE EXITING N AND E WED MORNING AHEAD OF THE
COLD FRONT AND THEN THE DRY SLOT WITH THE SYSTEM WILL MOVE IN FROM
THE SW WED LATE MORNING/AFTERNOON. ALTHOUGH THERE WILL BE STRONG 0-6
KM SHEAR ALONG THE FRONTAL BOUNDARY...HOWEVER AMOUNT OF INSTABILITY
(MODELS PROJECT 300-600 J/KG) REMAINS IN QUESTION AS THERE COULD BE
CONSIDERABLE CLOUD COVER LINGERING OVER THE AREA. BUT IF SUFFICIENT
INSTABILITY DEVELOPS AHEAD/ALONG THE FRONT...THERE COULD BE SOME
STRONG TO POSSIBLY SEVERE STORMS FORMING OVER MAINLY THE CENTRAL AND
ERN CWA IN THE MORNING. AFTER THE DRY SLOT MOVES INTO MAINLY THE
CENTRAL AND ERN CWA EXPECT SHRA TO GENERALLY DISSIPATE IN THE
AFTERNOON. WRAP AROUND PRECIP/MOISTURE WITH SYSTEM COULD MOVE INTO
WRN UPPER MI LATE IN THE DAY. WED LOOKS WINDY OVER CENTRAL AND ERN
UPPER MI WITH S-SW WINDS GUSTING TO 25-30 MPH.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 251 PM EDT TUE AUG 18 2015
THE ANOMALOUS UPPER TROUGH AND SURFACE LOW (AROUND 3-4 SIGMA) WILL
BE CENTERED BETWEEN DULUTH AND ISLE ROYALE AT THE START OF THE LONG
TERM FORECAST. THESE FEATURES WILL BE SLOWLY LIFTING TO THE
NORTHEAST THROUGH THURSDAY...BRINGING THE POTENTIAL FOR RAIN
SHOWERS AND BREEZY CONDITIONS TO THE AREA DURING THAT PERIOD.
STARTING OFF THE PERIOD...THE MID LEVEL DRY SLOT WILL BE OVER THE
CENTRAL AND EASTERN U.P. AND DON/T EXPECT MUCH MORE THAN LOW CLOUDS
FOR THE EVENING. BUT OVER THE WEST...WRAP AROUND MOISTURE WILL LEAD
TO SCATTERED/NUMEROUS SHOWERS WILL BE OCCURRING AND WILL LIKELY SEE
SOME ASSISTANCE FROM TERRAIN ENHANCEMENT WITH THE WEST-NORTHWEST
WINDS BEHIND THE SURFACE TROUGH THAT WILL BE LOCATED OVER THE
CENTRAL U.P. AT 06Z THURSDAY. AS THAT LOW LIFTS TO THE NORTHEAST
OVERNIGHT WEDNESDAY INTO THURSDAY...EXPECT THE SHOWERS TO SHIFT
EASTWARD BEHIND THE TROUGH AND MOVE OVER THE CENTRAL/EASTERN U.P.
ACCUMULATIONS WILL BE LIGHTER THAN OVER THE WEST WITH LESS TERRAIN
INFLUENCE...BUT SHOULD STILL SEE A FEW HUNDREDTHS BY LATE THURSDAY
AFTERNOON. WITH THE UPPER LOW QUICKLY MOVING TO THE NORTH THURSDAY
AFTERNOON INTO THURSDAY NIGHT...SHOULD SEE THE SHOWER COVERAGE
QUICKLY DIMINISH AS DRIER AIR ASSOCIATED WITH A SURFACE RIDGE MOVING
NORTHEAST INTO THE AREA. HAVE FOLLOWED THAT IDEA BOTH WITH THE POPS
AND CLOUD COVER THURSDAY AFTERNOON AND EVENING. IN FACT...SOME OF
THE AREAS NEAR THE WISCONSIN BORDER MAY HAVE THE LOW CLOUDS SCATTER
OUT BY EARLY AFTERNOON. IN ADDITION TO THE RAIN...EXPECT WINDS TO
INCREASE OVER AT LEAST THE WESTERN HALF OF THE CWA ON WEDNESDAY
NIGHT. THE DIFFERENCES IN THE MODELS LEADS TO SOME UNCERTAINTY IN
THE STRENGTH...BUT IT STILL APPEARS THAT GUSTS UP TO 30KTS ARE
POSSIBLE OVER THE KEWEENAW. FOR THE REST OF THE AREA...EXPECT GUSTS
IN THE 20-25KT RANGE ON THURSDAY.
THE HIGH PRESSURE RIDGE WILL BE NEAR THE AREA (FROM A HIGH IN THE
OHIO RIVER VALLEY) THROUGH FRIDAY NIGHT...BUT EXPECT THE GRADIENT
TO TIGHTEN THROUGH THAT PERIOD AS ANOTHER LOW DEVELOPS IN THE
NORTHERN PLAINS. THAT GRADIENT AND PLENTY OF SUNSHINE SHOULD LEAD TO
DECENT MIXING ON FRIDAY (AROUND 800MB)...RAISING TEMPERATURES TO
NORMAL OR SLIGHTLY ABOVE NORMAL VALUES UNDER OCCASIONALLY GUSTY
SOUTHWESTERLY WINDS (17-23KTS). WITH THE UPPER TROUGH AND SURFACE
LOW STILL NEAR THE NORTHERN PLAINS AND MOVING INTO THE UPPER
MISSISSIPPI VALLEY...EXPECT A SIMILAR DAY ON SATURDAY. HAVE REMOVED
THE POPS OVER THE WEST FOR SATURDAY AND WILL KEEP SKIES MOSTLY
SUNNY. SINCE THE TIGHTENING GRADIENT WILL REMAIN IN PLACE AHEAD OF
THE LOW...EXPECT WINDS TO BE A LITTLE GUSTIER THAN FRIDAY (UP TO
25KTS) AND TEMPERATURES TO BE A FEW DEGREES WARMER.
THE UPPER TROUGH FOR THE SECOND HALF OF THE WEEKEND
WILL MOVE THROUGH THE UPPER GREAT LAKES REGION OVERNIGHT SATURDAY
THROUGH SUNDAY EVENING. MEANWHILE...THE SURFACE LOW WILL LIFT
NORTH-NORTHEAST FROM NORTHWEST MINNESOTA TO FAR NORTHERN ONTARIO.
THIS WILL LEAD TO A SHARP COLD FRONT MOVING EAST ACROSS THE AREA ON
SUNDAY. MODELS SEEM TO BE FOCUSING ON LATE SATURDAY NIGHT AND
SUNDAY MORNING FOR THE FRONT TO MOVE THROUGH AND WILL FOCUS THE
HIGHEST POPS DURING THAT PERIOD (LOW LIKELY) AND QUICKLY RAMP
UP/DOWN ON BOTH SIDES. MODELS NOT SHOWING A WHOLE LOT OF INSTABILITY
AHEAD OF THE FRONT (MUCAPE VALUES ONLY UP TO 500 J/KG)...SO THINK
THAT THE THUNDER THREAT WILL BE LIMITED AND WILL CAP AT CHANCES.
THE COLD FRONT WILL USHER IN ANOTHER PERIOD OF BELOW NORMAL
TEMPERATURES FOR THE START OF NEXT WEEK AS HIGH PRESSURE BUILDS
OVER THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 253 PM EDT TUE AUG 18 2015
MAINLY MVFR CIGS ARE EXPECTED AT KSAW AND KCMX WITH CONTINUED MOIST
UPSLOPE E-NE FLOW THIS AFTERNOON. CIGS SHOULD ALSO LOWER AT IWD
TOWARD EVENING AS A STRENGTHENING ESE FLOW AHEAD OF DEEPENING LOW
PRES IN THE PLAINS WL BRING A RETURN OF MORE WDSPRD -RA/MVFR
CONDITIONS IN THE EVENING DROPPING TO IFR/LIFR OVERNIGHT. EXPECT
SLOWLY IMPROVING CONDITIONS BY LATE WED MORNING IN THE WAKE OF THE
FRONT ALONG WITH GUSTY SW WINDS NEAR 25 KTS AT KSAW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 327 PM EDT TUE AUG 18 2015
AS LOW PRES ORGANIZES AND STRENGTHENS OVER THE PLAINS THIS EVENING
...NE WINDS WILL BEGIN TO INCREASE...ESPECIALLY OVER WRN LAKE
SUPERIOR WHERE GUSTS SHOULD REACH 30KT LATE AFTN/EARLY EVENING. MAY
EVEN BE A FEW GALE GUSTS NEAR APOSTLE ISLANDS EARLY EVENING. THIS
LOW WILL BECOME UNSEASONABLY DEEP FOR AUG AS IT LIFTS ACROSS WRN
LAKE SUPERIOR WED AFTERNOON. 20-30KT WINDS ARE EXPECTED OVER MUCH OF
THE LAKE TONIGHT INTO WED. MAY SEE GALE FORCE GUSTS OVER FAR WRN
LAKE SUPERIOR IN THE NE WINDS AHEAD OF THE LOW TONIGHT AND THEN IN
THE WESTERLY WINDS ACROSS WRN AND CENTRAL LAKE SUPERIOR ON THU AS
THE LOW LIFTS N OF THE AREA. WINDS WILL DIMINISH TO UNDER 20KT BY
FRI...AND THEN BEGIN TO INCREASE SOME AGAIN ON SAT AHEAD OF THE NEXT
COLD FRONT MOVING OUT ACROSS THE PLAINS. &&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
257 PM EDT TUE AUG 18 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM EDT TUE AUG 18 2015
WV IMAGERY AND RAP ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
FROM NRN HUDSON BAY INTO THE NRN PLAINS RESULTING IN WNW FLOW
THROUGH THE NRN GREAT LAKES. A WEAK SHORTWAVE TROUGH AND AREA OF 850-
700 MB FGEN SUPPORTED A BAND OF SHOWERS OVER WRN UPPER MI. UPSTREAM
A VIGOROUS SHRTWV WAS MOVING THROUGH SD/NE. AT THE SFC...A WEAK
FRONTAL BOUNDARY EXTENDED FROM CNTRL LOWER MI THROUGH SE WI AND SW
IA TO LOW PRES OVER NRN KS. WITH HIGH PRES OVER NRN ONTARIO...LIGHT
NE WINDS PREVAILED ACROSS THE NRN LAKES.
EXPECT THE PCPN OVER THE WEST TO DIMINISH EARLY AS THE SHRTWV AND
FGEN LIFT MOVE OFF TO THE NORTHEAST. HOWEVER...SOME SCT -SHRA MAY
LINGER OVER THE SOUTH AS ANOTHER WEAK SHRTWV BRUSHES THE AREA TO THE
SE.
ATTENTION...WILL THEN TURN TO THE DEVELOPING AND UNSEASONABLY STRONG
LOW PRES SYSTEM MOVING OUT OF THE PLAINS. THE SD/NE SHRTWV WILL
SUPPORT A DEEPENING LOW MOVING INTO THE NW CORNER OF IA BY 00Z/WED
AND ERN MN BY 12Z/WED. THE MODELS HAVE TRENDED TOWARD A SLIGHTLY
SLOWER PROGRESSION OF THE LOW AS THE STRONG JET MOVING OUT OF THE
PLAINS HELPS CUT OFF THE MID LEVEL LOW. AN AREA OF STRONG MOISTURE
TRANSPORT AND 305K-310K ISENTROPIC ASCENT WILL BRING AN AREA OF RAIN
THROUGH UPPER MI TONIGHT...MAINLY AFTER MIDNIGHT. HOWEVER...THIS
TRANSIENT BAND IS EXPECTED TO BRING QPF AMOUNTS ONLY IN THE 0.25-
0.50 INCH RANGE OVER THE CNTRL AND ERN CWA. HIGHER AMOUNTS TO AROUND
AN INCH WILL BE POSSIBLE OVER THE FAR WEST CLOSER TO THE STRONGEST
DEEP LAYER QVECTOR CONV AND LIFT WHICH WILL REMAIN TO THE WEST OVER
NRN MN AND WRN LAKE SUPERIOR. WITH MODEST MUCAPE VALUES INTO THE 200-
400 J/KG RANGE ONLY ISOLD TSRA ARE EXPECTED.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 251 PM EDT TUE AUG 18 2015
THE ANOMALOUS UPPER TROUGH AND SURFACE LOW (AROUND 3-4 SIGMA) WILL
BE CENTERED BETWEEN DULUTH AND ISLE ROYALE AT THE START OF THE LONG
TERM FORECAST. THESE FEATURES WILL BE SLOWLY LIFTING TO THE
NORTHEAST THROUGH THURSDAY...BRINGING THE POTENTIAL FOR RAIN
SHOWERS AND BREEZY CONDITIONS TO THE AREA DURING THAT PERIOD.
STARTING OFF THE PERIOD...THE MID LEVEL DRY SLOT WILL BE OVER THE
CENTRAL AND EASTERN U.P. AND DON/T EXPECT MUCH MORE THAN LOW CLOUDS
FOR THE EVENING. BUT OVER THE WEST...WRAP AROUND MOISTURE WILL LEAD
TO SCATTERED/NUMEROUS SHOWERS WILL BE OCCURRING AND WILL LIKELY SEE
SOME ASSISTANCE FROM TERRAIN ENHANCEMENT WITH THE WEST-NORTHWEST
WINDS BEHIND THE SURFACE TROUGH THAT WILL BE LOCATED OVER THE
CENTRAL U.P. AT 06Z THURSDAY. AS THAT LOW LIFTS TO THE NORTHEAST
OVERNIGHT WEDNESDAY INTO THURSDAY...EXPECT THE SHOWERS TO SHIFT
EASTWARD BEHIND THE TROUGH AND MOVE OVER THE CENTRAL/EASTERN U.P.
ACCUMULATIONS WILL BE LIGHTER THAN OVER THE WEST WITH LESS TERRAIN
INFLUENCE...BUT SHOULD STILL SEE A FEW HUNDREDTHS BY LATE THURSDAY
AFTERNOON. WITH THE UPPER LOW QUICKLY MOVING TO THE NORTH THURSDAY
AFTERNOON INTO THURSDAY NIGHT...SHOULD SEE THE SHOWER COVERAGE
QUICKLY DIMINISH AS DRIER AIR ASSOCIATED WITH A SURFACE RIDGE MOVING
NORTHEAST INTO THE AREA. HAVE FOLLOWED THAT IDEA BOTH WITH THE POPS
AND CLOUD COVER THURSDAY AFTERNOON AND EVENING. IN FACT...SOME OF
THE AREAS NEAR THE WISCONSIN BORDER MAY HAVE THE LOW CLOUDS SCATTER
OUT BY EARLY AFTERNOON. IN ADDITION TO THE RAIN...EXPECT WINDS TO
INCREASE OVER AT LEAST THE WESTERN HALF OF THE CWA ON WEDNESDAY
NIGHT. THE DIFFERENCES IN THE MODELS LEADS TO SOME UNCERTAINTY IN
THE STRENGTH...BUT IT STILL APPEARS THAT GUSTS UP TO 30KTS ARE
POSSIBLE OVER THE KEWEENAW. FOR THE REST OF THE AREA...EXPECT GUSTS
IN THE 20-25KT RANGE ON THURSDAY.
THE HIGH PRESSURE RIDGE WILL BE NEAR THE AREA (FROM A HIGH IN THE
OHIO RIVER VALLEY) THROUGH FRIDAY NIGHT...BUT EXPECT THE GRADIENT
TO TIGHTEN THROUGH THAT PERIOD AS ANOTHER LOW DEVELOPS IN THE
NORTHERN PLAINS. THAT GRADIENT AND PLENTY OF SUNSHINE SHOULD LEAD TO
DECENT MIXING ON FRIDAY (AROUND 800MB)...RAISING TEMPERATURES TO
NORMAL OR SLIGHTLY ABOVE NORMAL VALUES UNDER OCCASIONALLY GUSTY
SOUTHWESTERLY WINDS (17-23KTS). WITH THE UPPER TROUGH AND SURFACE
LOW STILL NEAR THE NORTHERN PLAINS AND MOVING INTO THE UPPER
MISSISSIPPI VALLEY...EXPECT A SIMILAR DAY ON SATURDAY. HAVE REMOVED
THE POPS OVER THE WEST FOR SATURDAY AND WILL KEEP SKIES MOSTLY
SUNNY. SINCE THE TIGHTENING GRADIENT WILL REMAIN IN PLACE AHEAD OF
THE LOW...EXPECT WINDS TO BE A LITTLE GUSTIER THAN FRIDAY (UP TO
25KTS) AND TEMPERATURES TO BE A FEW DEGREES WARMER.
THE UPPER TROUGH FOR THE SECOND HALF OF THE WEEKEND
WILL MOVE THROUGH THE UPPER GREAT LAKES REGION OVERNIGHT SATURDAY
THROUGH SUNDAY EVENING. MEANWHILE...THE SURFACE LOW WILL LIFT
NORTH-NORTHEAST FROM NORTHWEST MINNESOTA TO FAR NORTHERN ONTARIO.
THIS WILL LEAD TO A SHARP COLD FRONT MOVING EAST ACROSS THE AREA ON
SUNDAY. MODELS SEEM TO BE FOCUSING ON LATE SATURDAY NIGHT AND
SUNDAY MORNING FOR THE FRONT TO MOVE THROUGH AND WILL FOCUS THE
HIGHEST POPS DURING THAT PERIOD (LOW LIKELY) AND QUICKLY RAMP
UP/DOWN ON BOTH SIDES. MODELS NOT SHOWING A WHOLE LOT OF INSTABILITY
AHEAD OF THE FRONT (MUCAPE VALUES ONLY UP TO 500 J/KG)...SO THINK
THAT THE THUNDER THREAT WILL BE LIMITED AND WILL CAP AT CHANCES.
THE COLD FRONT WILL USHER IN ANOTHER PERIOD OF BELOW NORMAL
TEMPERATURES FOR THE START OF NEXT WEEK AS HIGH PRESSURE BUILDS
OVER THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 253 PM EDT TUE AUG 18 2015
MAINLY MVFR CIGS ARE EXPECTED AT KSAW AND KCMX WITH CONTINUED MOIST
UPSLOPE E-NE FLOW THIS AFTERNOON. CIGS SHOULD ALSO LOWER AT IWD
TOWARD EVENING AS A STRENGTHENING ESE FLOW AHEAD OF DEEPENING LOW
PRES IN THE PLAINS WL BRING A RETURN OF MORE WDSPRD -RA/MVFR
CONDITIONS IN THE EVENING DROPPING TO IFR/LIFR OVERNIGHT. EXPECT
SLOWLY IMPROVING CONDITIONS BY LATE WED MORNING IN THE WAKE OF THE
FRONT ALONG WITH GUSTY SW WINDS NEAR 25 KTS AT KSAW. &&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 514 AM EDT TUE AUG 18 2015
HIGH PRES STRETCHING FROM SOUTHERN MANITOBA THROUGH JAMES BAY WILL
EXTEND A RIDGE INTO THE UPPER LAKES THROUGH THIS MORNING...RESULTING
IN LIGHT WINDS UNDER 15KT ACROSS LAKE SUPERIOR. THEN...AS LOW PRES
ORGANIZES AND STRENGTHENS OVER THE PLAINS TUE...NE WINDS WILL BEGIN
TO INCREASE...ESPECIALLY OVER WRN LAKE SUPERIOR WHERE GUSTS SHOULD
REACH 25-30KT LATE AFTN/EARLY EVENING. THIS LOW WILL BECOME
UNSEASONABLY DEEP FOR AUG AS IT LIFTS ACROSS FAR WRN LAKE SUPERIOR
WED AFTERNOON. 20-30KT WINDS ARE EXPECTED OVER MUCH OF THE LAKE
TONIGHT INTO WED. MAY SEE GALE FORCE GUSTS OVER FAR WRN LAKE SUPERIOR
IN THE NE WINDS AHEAD OF THE LOW TONIGHT AND THEN IN THE WESTERLY
WINDS ACROSS MAINLY CENTRAL LAKE SUPERIOR ON THU AS THE LOW LIFTS N
OF THE AREA. WINDS WILL DIMINISH TO UNDER 20KT FRI...AND THEN BEGIN
TO INCREASE AGAIN ON SAT AHEAD OF THE NEXT COLD FRONT MOVING OUT
ACROSS THE PLAINS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...VOSS
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
253 PM EDT TUE AUG 18 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM EDT TUE AUG 18 2015
WV IMAGERY AND RAP ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
FROM NRN HUDSON BAY INTO THE NRN PLAINS RESULTING IN WNW FLOW
THROUGH THE NRN GREAT LAKES. A WEAK SHORTWAVE TROUGH AND AREA OF 850-
700 MB FGEN SUPPORTED A BAND OF SHOWERS OVER WRN UPPER MI. UPSTREAM
A VIGOROUS SHRTWV WAS MOVING THROUGH SD/NE. AT THE SFC...A WEAK
FRONTAL BOUNDARY EXTENDED FROM CNTRL LOWER MI THROUGH SE WI AND SW
IA TO LOW PRES OVER NRN KS. WITH HIGH PRES OVER NRN ONTARIO...LIGHT
NE WINDS PREVAILED ACROSS THE NRN LAKES.
EXPECT THE PCPN OVER THE WEST TO DIMINISH EARLY AS THE SHRTWV AND
FGEN LIFT MOVE OFF TO THE NORTHEAST. HOWEVER...SOME SCT -SHRA MAY
LINGER OVER THE SOUTH AS ANOTHER WEAK SHRTWV BRUSHES THE AREA TO THE
SE.
ATTENTION...WILL THEN TURN TO THE DEVELOPING AND UNSEASONABLY STRONG
LOW PRES SYSTEM MOVING OUT OF THE PLAINS. THE SD/NE SHRTWV WILL
SUPPORT A DEEPENING LOW MOVING INTO THE NW CORNER OF IA BY 00Z/WED
AND ERN MN BY 12Z/WED. THE MODELS HAVE TRENDED TOWARD A SLIGHTLY
SLOWER PROGRESSION OF THE LOW AS THE STRONG JET MOVING OUT OF THE
PLAINS HELPS CUT OFF THE MID LEVEL LOW. AN AREA OF STRONG MOISTURE
TRANSPORT AND 305K-310K ISENTROPIC ASCENT WILL BRING AN AREA OF RAIN
THROUGH UPPER MI TONIGHT...MAINLY AFTER MIDNIGHT. HOWEVER...THIS
TRANSIENT BAND IS EXPECTED TO BRING QPF AMOUNTS ONLY IN THE 0.25-
0.50 INCH RANGE OVER THE CNTRL AND ERN CWA. HIGHER AMOUNTS TO AROUND
AN INCH WILL BE POSSIBLE OVER THE FAR WEST CLOSER TO THE STRONGEST
DEEP LAYER QVECTOR CONV AND LIFT WHICH WILL REMAIN TO THE WEST OVER
NRN MN AND WRN LAKE SUPERIOR. WITH MODEST MUCAPE VALUES INTO THE 200-
400 J/KG RANGE ONLY ISOLD TSRA ARE EXPECTED.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 251 PM EDT TUE AUG 18 2015
THE ANOMALOUS UPPER TROUGH AND SURFACE LOW (AROUND 3-4 SIGMA) WILL
BE CENTERED BETWEEN DULUTH AND ISLE ROYALE AT THE START OF THE LONG
TERM FORECAST. THESE FEATURES WILL BE SLOWLY LIFTING TO THE
NORTHEAST THROUGH THURSDAY...BRINGING THE POTENTIAL FOR RAIN
SHOWERS AND BREEZY CONDITIONS TO THE AREA DURING THAT PERIOD.
STARTING OFF THE PERIOD...THE MID LEVEL DRY SLOT WILL BE OVER THE
CENTRAL AND EASTERN U.P. AND DON/T EXPECT MUCH MORE THAN LOW CLOUDS
FOR THE EVENING. BUT OVER THE WEST...WRAP AROUND MOISTURE WILL LEAD
TO SCATTERED/NUMEROUS SHOWERS WILL BE OCCURRING AND WILL LIKELY SEE
SOME ASSISTANCE FROM TERRAIN ENHANCEMENT WITH THE WEST-NORTHWEST
WINDS BEHIND THE SURFACE TROUGH THAT WILL BE LOCATED OVER THE
CENTRAL U.P. AT 06Z THURSDAY. AS THAT LOW LIFTS TO THE NORTHEAST
OVERNIGHT WEDNESDAY INTO THURSDAY...EXPECT THE SHOWERS TO SHIFT
EASTWARD BEHIND THE TROUGH AND MOVE OVER THE CENTRAL/EASTERN U.P.
ACCUMULATIONS WILL BE LIGHTER THAN OVER THE WEST WITH LESS TERRAIN
INFLUENCE...BUT SHOULD STILL SEE A FEW HUNDREDTHS BY LATE THURSDAY
AFTERNOON. WITH THE UPPER LOW QUICKLY MOVING TO THE NORTH THURSDAY
AFTERNOON INTO THURSDAY NIGHT...SHOULD SEE THE SHOWER COVERAGE
QUICKLY DIMINISH AS DRIER AIR ASSOCIATED WITH A SURFACE RIDGE MOVING
NORTHEAST INTO THE AREA. HAVE FOLLOWED THAT IDEA BOTH WITH THE POPS
AND CLOUD COVER THURSDAY AFTERNOON AND EVENING. IN FACT...SOME OF
THE AREAS NEAR THE WISCONSIN BORDER MAY HAVE THE LOW CLOUDS SCATTER
OUT BY EARLY AFTERNOON. IN ADDITION TO THE RAIN...EXPECT WINDS TO
INCREASE OVER AT LEAST THE WESTERN HALF OF THE CWA ON WEDNESDAY
NIGHT. THE DIFFERENCES IN THE MODELS LEADS TO SOME UNCERTAINTY IN
THE STRENGTH...BUT IT STILL APPEARS THAT GUSTS UP TO 30KTS ARE
POSSIBLE OVER THE KEWEENAW. FOR THE REST OF THE AREA...EXPECT GUSTS
IN THE 20-25KT RANGE ON THURSDAY.
THE HIGH PRESSURE RIDGE WILL BE NEAR THE AREA (FROM A HIGH IN THE
OHIO RIVER VALLEY) THROUGH FRIDAY NIGHT...BUT EXPECT THE GRADIENT
TO TIGHTEN THROUGH THAT PERIOD AS ANOTHER LOW DEVELOPS IN THE
NORTHERN PLAINS. THAT GRADIENT AND PLENTY OF SUNSHINE SHOULD LEAD TO
DECENT MIXING ON FRIDAY (AROUND 800MB)...RAISING TEMPERATURES TO
NORMAL OR SLIGHTLY ABOVE NORMAL VALUES UNDER OCCASIONALLY GUSTY
SOUTHWESTERLY WINDS (17-23KTS). WITH THE UPPER TROUGH AND SURFACE
LOW STILL NEAR THE NORTHERN PLAINS AND MOVING INTO THE UPPER
MISSISSIPPI VALLEY...EXPECT A SIMILAR DAY ON SATURDAY. HAVE REMOVED
THE POPS OVER THE WEST FOR SATURDAY AND WILL KEEP SKIES MOSTLY
SUNNY. SINCE THE TIGHTENING GRADIENT WILL REMAIN IN PLACE AHEAD OF
THE LOW...EXPECT WINDS TO BE A LITTLE GUSTIER THAN FRIDAY (UP TO
25KTS) AND TEMPERATURES TO BE A FEW DEGREES WARMER.
THE UPPER TROUGH FOR THE SECOND HALF OF THE WEEKEND
WILL MOVE THROUGH THE UPPER GREAT LAKES REGION OVERNIGHT SATURDAY
THROUGH SUNDAY EVENING. MEANWHILE...THE SURFACE LOW WILL LIFT
NORTH-NORTHEAST FROM NORTHWEST MINNESOTA TO FAR NORTHERN ONTARIO.
THIS WILL LEAD TO A SHARP COLD FRONT MOVING EAST ACROSS THE AREA ON
SUNDAY. MODELS SEEM TO BE FOCUSING ON LATE SATURDAY NIGHT AND
SUNDAY MORNING FOR THE FRONT TO MOVE THROUGH AND WILL FOCUS THE
HIGHEST POPS DURING THAT PERIOD (LOW LIKELY) AND QUICKLY RAMP
UP/DOWN ON BOTH SIDES. MODELS NOT SHOWING A WHOLE LOT OF INSTABILITY
AHEAD OF THE FRONT (MUCAPE VALUES ONLY UP TO 500 J/KG)...SO THINK
THAT THE THUNDER THREAT WILL BE LIMITED AND WILL CAP AT CHANCES.
THE COLD FRONT WILL USHER IN ANOTHER PERIOD OF BELOW NORMAL
TEMPERATURES FOR THE START OF NEXT WEEK AS HIGH PRESSURE BUILDS
OVER THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 742 AM EDT TUE AUG 18 2015
MAINLY MVFR CIGS ARE EXPECTED AT SAW WITH CONTINUED MOIST UPSLOPE NE
FLOW TODAY. CIGS SHOULD ALSO LOWER AT IWD AND CMX BUT WITH DRIER AIR
IN PLACE...EXPECT CONDITIONS TO REMAIN VFR UNTIL LATER THIS
AFTERNOON. A STRENGTHENING ESE FLOW AHEAD OF DEEPENING LO PRES IN
THE PLAINS WL BRING A RETURN OF MORE WDSPRD -RA/MVFR CONDITIONS IN
THE EVENING DROPPING TO IFR OVERNIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 514 AM EDT TUE AUG 18 2015
HIGH PRES STRETCHING FROM SOUTHERN MANITOBA THROUGH JAMES BAY WILL
EXTEND A RIDGE INTO THE UPPER LAKES THROUGH THIS MORNING...RESULTING
IN LIGHT WINDS UNDER 15KT ACROSS LAKE SUPERIOR. THEN...AS LOW PRES
ORGANIZES AND STRENGTHENS OVER THE PLAINS TUE...NE WINDS WILL BEGIN
TO INCREASE...ESPECIALLY OVER WRN LAKE SUPERIOR WHERE GUSTS SHOULD
REACH 25-30KT LATE AFTN/EARLY EVENING. THIS LOW WILL BECOME
UNSEASONABLY DEEP FOR AUG AS IT LIFTS ACROSS FAR WRN LAKE SUPERIOR
WED AFTERNOON. 20-30KT WINDS ARE EXPECTED OVER MUCH OF THE LAKE
TONIGHT INTO WED. MAY SEE GALE FORCE GUSTS OVER FAR WRN LAKE SUPERIOR
IN THE NE WINDS AHEAD OF THE LOW TONIGHT AND THEN IN THE WESTERLY
WINDS ACROSS MAINLY CENTRAL LAKE SUPERIOR ON THU AS THE LOW LIFTS N
OF THE AREA. WINDS WILL DIMINISH TO UNDER 20KT FRI...AND THEN BEGIN
TO INCREASE AGAIN ON SAT AHEAD OF THE NEXT COLD FRONT MOVING OUT
ACROSS THE PLAINS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GAYLORD MI
113 PM EDT TUE AUG 18 2015
.UPDATE...
ISSUED AT 1033 AM EDT TUE AUG 18 2015
SCT/NMRS SHOWERS CONTINUE TO DEVELOP ACROSS MUCH OF THE WRN GREAT
LAKES LATE THIS MORNING...INCLUDING OUR CWA WHERE SOME BRIEF ISOLD
THUNDER HAS ALSO DEVELOPED PER RECENT LIGHTNING DATA. FORCING
REMAINS WEAK...WITH LITTLE IN THE WAY TO ORGANIZE ANY OF THE
CONVECTION. WARM FRONT IS TRYING TO PUSH NORTHWARD INTO SRN
SECTIONS OF OUR CWA...BUT IS MAKING LITTLE PROGRESS GIVEN THICK
CLOUD COVER AND PRECIP ACROSS OUR AREA. CLOUDS AND PRECIP ARE ALSO
GREATLY LIMITING THE POTENTIAL FOR INCREASED INSTABILITY AS THE
DAY SLOWLY HEATS UP. ALL OF THE ABOVE WILL REMAIN IN PLACE THRU
THE AFTERNOON...WHICH WILL CONTINUE TO LIMIT OUR THUNDER CHANCES.
HOWEVER...DO STILL EXPECT PRECIP ITSELF WILL GRADUALLY EXPAND
THANKS TO SOME DIURNALLY-ENHANCED INSTABILITY AND AMPLE MOISTURE
POOLING ALONG AND NORTH OF THE WARM FRONT. HAVE MADE ONLY MINOR
ADJUSTMENTS TO WX/POP FORECAST FOR THE AFTERNOON. OVERALL...EXPECT
A MAINLY CLOUDY AFTERNOON WITH WAVES OF SHOWERS AND POSSIBLY A FEW
THUNDERSTORMS...WITH THE HIGHEST POPS ACROSS NRN LWR MICHIGAN.
&&
.NEAR TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 328 AM EDT TUE AUG 18 2015
HIGH IMPACT WEATHER POTENTIAL...NON-SEVERE THUNDERSTORMS TODAY AND
TONIGHT.
DIFFUSE COLD FRONT RESTS ROUGHLY FROM OSC TO MBL. THIS FRONT IS
STALLING OUT...AS LEE CYCLOGENESIS GETS UNDERWAY IN THE CENTRAL
HIGH PLAINS. SOME SHRA ARE SEEN OVER CENTRAL/NORTHERN LAKE MI AND
SURROUNDING AREAS. A FEW SHRA HAVE ALSO RECENTLY DEVELOPED JUST SW
OF LAN. NO THUNDER LEFT IN OUR NECK OF THE WOODS. THE FRONT WILL
WOBBLE ACROSS CENTRAL/NORTHERN LOWER MI OVER THE NEXT 24
HOURS...AS HEATING/CONVECTION/SOUTHERLY FLOW WAXES AND WANES.
PRECIP TRENDS ARE THE MAIN CONCERN.
TODAY...A POTENT SHORTWAVE WILL DIG FROM THE NORTHERN TO CENTRAL
HIGH PLAINS TODAY. IN RESPONSE...PRESSURES WILL RAPIDLY FALL IN THE
CENTRAL PLAINS. BY MID-EVENING...A SUB-1000MB LOW WILL BE MOVING
INTO NW IOWA. SOUTHERLY 1000-850MB FLOW INTO LOWER MI WILL INCREASE
TO SOME DEGREE...THOUGH THE TIGHTEST PRESSURE GRADIENT WILL REMAIN
TO OUR WEST THRU 00Z. STILL...THAT AND DIURNAL HEATING/MIXING WILL
TEND TO PUSH THE FRONT NORTH. HOWEVER...PRECIP AND SUBSEQUENT COLD-
POOL GENERATION NORTH OF THE FRONT WILL WORK TO SUPPRESS ANY
NORTHWARD MOVEMENT. THE NAM WANTS TO PUSH THE FRONT QUICKLY NORTH IN
THE 1ST HALF OF THE DAY...AN INTERNALLY INCONSISTENT APPROACH SINCE
IT IS ALSO AMONG THE WETTEST SOLUTIONS NORTH OF THE FRONT THIS
MORNING. THE RAP OFFERS A BETTER ALTERNATIVE IN THE NEAR-TERM...WITH
THE FRONT REACHING A MANTON-HARRISVILLE LINE BY MIDDAY...BEFORE
GETTING ABRUPTLY SHOVED SOUTHWARD AGAIN AS PRECIP BECOMES MORE
EXPANSIVE.
SPEAKING OF WHICH...THERE ARE A PAIR OF SHORTWAVES MOVING EAST
TOWARD THE LAKES REGION EARLY THIS MORNING...ONE IN W CENTRAL WI AND
THE 2ND IN NW IL. THESE WILL BOTH ACT TO PROVIDE FORCING FOR ASCENT
JUST AFTER SUNRISE IN WESTERN SECTIONS. HOWEVER...AT THIS TIME OF
DAY NEITHER HAS MUCH IN THE WAY OF INSTABILITY TO WORK WITH. NOTE
THAT ACTIVITY MOVING ENE OUT OF CHICAGO IS FIZZLING RAPIDLY OVER
SOUTHERN LAKE MI. GENERALLY THINK THAT...THRU 10AM...THE MAIN PRECIP
CHANCES WILL BE WEST OF TVC/CAD...IN EASTERN UPPER MI...AND IN
PARTS OF NE LOWER (IF DOWNSTATE ACTIVITY DEVELOPS NE-WARD AS
AGGRESSIVELY AS RECENT RAP RUNS SUGGEST).
HOWEVER...WE HAVE PLENTY OF MOISTURE (PWATS 1.5-1.7) AND SOME
FORCING FOR ASCENT AVAILABLE. SO IT WILL TAKE VERY LITTLE HEATING
(EVEN WITH CONSIDERABLE CLOUD COVER) TO PRIME THE AIRMASS FOR
CONVECTION. THIS IS ESPECIALLY THE CASE GIVEN THAT (AS OPPOSED TO
YESTERDAY) WE ACTUALLY HAVE CROSS-FRONTAL 1000-850MB FLOW.
ANTICIPATE SHRA WILL RAPIDLY EXPAND IN COVERAGE OVER NW LOWER MI
BETWEEN 10AM AND NOON. FURTHER EXPANSION ACROSS THE BULK OF NORTHERN
LOWER WILL OCCUR AS ACTIVITY CONTINUES TO PERCOLATE THRU THE
AFTERNOON. SOME OF THIS ACTIVITY WILL LEAK INTO EASTERN UPPER...BUT
THAT FAR NORTH OF THE WARM FRONT SUSPECT COVERAGE THERE WILL BE LESS
THAN THE NAM/GFS ARGUE. CONVECTION WILL BE QUICK TO TRIGGER...SO WE
WON/T REALLY GET THE CHANCE TO BUILD UP MUCH IN THE WAY OF CAPE.
MLCAPES SHOULD STAY LESS THAN 500J/KG. THIS WILL KEEP PRECIP MAINLY
AS SHRA...WITH A FEW EMBEDDED TSRA...AND NO SVR THREAT. LOCALIZED
RAINFALL AMOUNTS OF A QUARTER TO HALF AN INCH WILL BE SEEN.
WILL BE A MUGGY DAY...BUT TEMPS WILL BE SHARPLY LIMITED BY
CLOUDS/PRECIP. HIGHS WILL BE MAINLY IN THE 70S...PEAKING UP CLOSE TO
80F IN A FEW SPOTS.
TONIGHT...PRIMARY 500MB CIRCULATION CLOSES OFF AND DEEPENS AS IT
MOVES FROM EASTERN SD TO SOUTHERN MN. THE CORRESPONDING SURFACE LOW
WILL DEEPEN TO 994MB AS IT MOVES TO THE MN/WI BORDER. IN ADVANCE OF
THIS DEVELOPING CYCLONE...SOUTHERLY 850MB WINDS WILL INCREASE TO 20-
30KT. THIS WILL PUSH THE SURFACE WARM FRONT MORE EMPHATICALLY
NORTHWARD TOWARD FAR NORTHERN LOWER OR THE STRAITS REGION. CHANCES
FOR PRECIP WILL DECREASE BEHIND THE FRONT. SHRA COVERAGE WILL BE
CONSIDERABLE ACROSS THE FORECAST AREA IN THE EVENING...BUT POPS WILL
DECREASE (THOUGH NOT DISAPPEAR) SOUTH OF M-32 OVERNIGHT. IN
ADDITION...IT IS LIKELY OVERNIGHT THAT ONE OR MORE MCS/S WILL BE
MOVING EAST IN THE WARM SECTOR INTO THE SW LAKES REGION. DON/T THINK
THAT THESE WILL HOLD TOGETHER AND REACH SW SECTIONS TOWARD
DAYBREAK...BUT IT/S NOT IMPOSSIBLE. THAT/S OUR VERY LOW-END SHOT AT
ANYTHING SVR...OTHERWISE MLCAPE IS TOO LIMITED.
STILL MUGGY AND A VERY WARM NIGHT...WITH LOWS IN THE MID 60S TO
AROUND 70F.
&&
.SHORT TERM...(WEDNESDAY THROUGH THURSDAY NIGHT)
ISSUED AT 328 AM EDT TUE AUG 18 2015
LOW PRESSURE EMERGES OUT OF THE CENTRAL PLAINS TODAY THEN HEADS
NORTHEAST INTO THE NORTHERN MISSISSIPPI VALLEY WHILE DEEPENING. THE
IMPACTS FROM THIS SYSTEM WILL BE THE FOCUS OF THE FORECAST WITH THE
MAIN CHALLENGE BEING THE POTENTIAL FOR SEVERE STORMS WEDNESDAY.
WEDNESDAY...THE TRACK OF A NEGATIVELY TILTED TROUGH AND ASSOCIATED
AREA OF DEEPENING LOW PRESSURE TO OUR NORTHWEST IS EXPECTED TO LEAD
TO A SOLID AREA OF SHOWERS ACROSS EASTERN UPPER AND FAR NORTHWEST
LOWER WEDNESDAY WITH SLIGHTLY LESSER BUT MORE CONVECTIVE
SHOWER/STORM COVERAGE ACROSS SOUTHEAST ZONES. THERE IS A THREAT FOR
SEVERE STORMS...MAINLY BECAUSE OF STRONGER WINDS ALOFT (NAM 0-6KM
BULK SHEAR 30 TO 40 KNOTS WITH THE MORE BULLISH GFS A ROBUST 50 TO
55 KNOTS!). IN ADDITION TO THE STRONG WINDS ALOFT NORTHEAST LOWER
MAY ALSO GET INTO HEALTHY AMOUNTS OF INSTABILITY IF THE SUN IS ABLE
TO BREAK OUT IN THE DRY SLOT. SO NOT SURPRISINGLY...SPC HAS JUST
PLACED ALL OF NORTHERN LOWER IN A SLIGHT RISK FOR WIND AND/OR HAIL.
MODELS CONTINUE TO DIFFER ON THE FINER DETAILS OF THIS SYSTEM
INCLUDING TIMING AND STRENGTH (THOUGH BOTH THE ECMWF AND GFS ARE
TRENDING STRONGER) SO STAY TUNED FOR FURTHER UPDATES AS THIS
POSSIBLE EVENT GETS A LITTLE CLOSER. A SYSTEM THIS DEEP THIS TIME OF
THE YEAR IS A BIT UNUSUAL SO THINGS HAVE THE POTENTIAL TO GET
INTERESTING. HIGHS RANGING FROM THE MUGGY UPPER 70S NORTH TO PERHAPS
THE TOASTY UPPER 80S SOUTHEAST ZONES.
WEDNESDAY NIGHT...A FEW MORE SHOWERS (AND THUNDERSTORMS EAST) ARE
LIKELY AS THE COLD FRONT ASSOCIATED WITH THE LOW PRESSURE SYSTEM
MOVES ACROSS THE REGION (ACTUALLY IT MAY BE MORE OF AN OCCLUDED
FRONT AT THAT POINT). LOWS RANGING FROM THE UPPER 50S TO MIDDLE 60S.
THURSDAY...WRAP AROUND SHOWERS ARE POSSIBLE ACROSS EASTERN UPPER AND
FAR NORTHERN LOWER...ESPECIALLY IN THE MORNING. COOLER WITH HIGHS
ONLY IN THE UPPER 60S AND LOWER 70S.
&&
.LONG TERM...(FRIDAY THROUGH MONDAY)
ISSUED AT 328 AM EDT TUE AUG 18 2015
HIGH PRESSURE BUILDS IN FRIDAY WHICH SHOULD HOLD ON THROUGH SATURDAY
NIGHT YIELDING WARMER AND DRIER CONDITIONS. ANOTHER AREA OF LOW
PRESSURE TRACKING BY TO OUR NORTHWEST WILL THEN BRING MORE CHANCES
FOR SHOWERS AND THUNDERSTORMS SUNDAY...WITH WRAP AROUND DRIVEN
SHOWERS POSSIBLY LINGERING INTO MONDAY (MODELS ARE NOT IN AGREEMENT
HERE BUT PLENTY OF TIME TO MAKE ADJUSTMENTS). HIGHS BACK IN THE
UPPER 70S AND LOWER 80S FRIDAY THROUGH SUNDAY. COOLER AGAIN FOR
MONDAY WITH HIGHS IN THE UPPER 60S AND LOWER 70S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 113 PM EDT TUE AUG 18 2015
MVFR/LOW VFR CIGS WILL HOLD OVER ALL NRN LWR MICHIGAN TAF SITES
THRU TONIGHT AS A STALLED WARM FRONT TRIES TO LIFT THRU THE
REGION. SCT/NMRS SHOWERS AND AN ISOLD THUNDERSTORM WILL CONTINUE
TO DRIFT THRU THE REGION THIS AFTERNOON AND TONIGHT ALONG AND
NORTH OF THE WARM FRONT. WINDS WILL REMAIN FROM THE E/SE UNDER 10
KTS THRU TONIGHT...BUT WILL STRENGTHEN AND SWITCH TO THE S/SW ON
WEDNESDAY AS DEEP LOW PRESSURE LIFTS INTO WRN UPR MICHIGAN AND A
COLD FRONT SWEEPS THRU ERN UPR AND LWR MICHIGAN. THIS SYSTEM WILL
INCREASE OUR CHANCES OF SHOWERS AND STORMS...AND MAY PRODUCE SOME
STRONG/SVR STORMS ON WEDNESDAY. OVERALL CONDITIONS WILL REMAIN
MVFR/LOW VFR AS THIS SYSTEM IMPACT THE REGION ON WEDNESDAY. CIGS
AND VSBYS WILL BE LOWER WITHIN ANY THUNDERSTORMS.
&&
.MARINE...
ISSUED AT 328 AM EDT TUE AUG 18 2015
A STALLED FRONT WILL WOBBLE ACROSS CENTRAL LOWER MI TODAY...BEFORE
MOVING NORTH TONIGHT AS A WARM FRONT. SE-ERLY WINDS WILL BE LIGHT
THRU THIS EVENING...BUT INCREASE OVERNIGHT. SMALL CRAFT
ADVISORIES WILL LIKELY BE NEEDED ON SOME WATERS BY WEDNESDAY
AFTERNOON. A STRONG COLD FRONT WILL CROSS THE REGION LATE
WEDNESDAY...WITH STRONG TO POTENTIALLY SVR THUNDERSTORMS.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...MLR
NEAR TERM...JAZ
SHORT TERM...SULLIVAN
LONG TERM...SULLIVAN
AVIATION...MLR
MARINE...JAZ
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
258 PM CDT TUE AUG 18 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 258 PM CDT TUE AUG 18 2015
VERY POWERFUL LOW PRESSURE MOVING FROM SOUTHWEST MN TO THE ARROWHEAD
REGION BY WEDNESDAY EVENING. IT IS VERY RARE TO SEE SUCH A STRONG
LOW PRESSURE SYSTEM IN THE SUMMER. IN FACT IT MAY WELL RIVAL THE LOW
PRESSURE RECORD FOR MSP. THE HRRR AND HOPWRF ARE IN GOOD AGREEMENT
AND HAVE DONE WELL THE LAST FEW HOURS. RADAR AND OBS SUPPORT THE
IDEA OF LESS PRECIPITATION IN TERMS OF AMOUNTS AND LESS CHANCES FOR
THUNDER AFTER 02Z THIS EVENING ACROSS THE AREA. DRY SLOT REALLY TOOK
OVER FOR THIS EVENT IN SRN MN. EXPECT THE COMMA HEAD WRAP-AROUND
PRECIPITATION TO AFFECT WESTERN MN LATE THIS AFTERNOON AND SLOWLY
LIFT EAST AND NORTH THROUGH THE EVENING AND OVERNIGHT HOURS. MAIN
PRECIPITATION WILL BE OVER WRN MN AND EXTENDING TO THE ARROWHEAD. WE
CAN EXPECT SCATTERED RAIN AND AN ISOLATED SHOWER OVER CENTRAL MN
INTO WRN WI THROUGH THE OVERNIGHT HOURS...MAYBE DRIZZLE. RAIN SHOULD
DIMINSH TOWARD MORNING AND THEN SEE AN INCREASE BY MID DAY. STRONG
WINDS WILL MOVE IN OVERNIGHT WITH GUSTS INTO THE MID 30 MPH RANGE
WEDNESDAY AFTERNOON WITH MOSTLY CLOUDY SKIES AND COOL TEMPERATURES.
VERY MUCH LIKE OCTOBER.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 258 PM CDT TUE AUG 18 2015
PICKING UP THE FORECAST WEDNESDAY NIGHT...THE FOCUS REMAINS GETTING
THIS INCREDIBLY STRONG MID AUGUST SYNOPTIC SCALE STORM SYSTEM OUT OF
HERE. BY THIS POINT...THE SURFACE LOW SHOULD BE POSITIONED OVER
WESTERN LAKE SUPERIOR AND SLIDING NORTHEAST. IT WILL BE ESSENTIALLY
VERTICALLY STACKED AND BEGIN WEAKENING OVERNIGHT. THE HIGHLY
AMPLIFIED 500MB TROUGH WILL INTRODUCE DRY NORTHWESTERLY FLOW INTO
WESTERN MN WHICH WILL EXPAND EASTWARD BY THURSDAY MORNING. DRY AIR
WILL ACCOMPANY THE NORTHWESTERLY FLOW...SO WE`LL SEE THE CLOUDS
BEGIN TO CLEAR FROM WEST TO EAST OVERNIGHT IN WESTERN MN...THROUGH
WESTERN WI BY MIDDAY THURSDAY. WITH CLEARING SKIES...AND THE LOW
MOVING OFF...WE`LL SEE TEMPERATURES REBOUND INTO THE MID 70S FOR
HIGHS. WESTERLY WINDS AT THE SURFACE OF 10-15 MPH ARE EXPECTED
THURSDAY...SO MUCH LESS WINDY THAN WEDNESDAY.
BY FRIDAY...A LOW PRESSURE SYSTEM WILL BE DEVELOPING NEAR
MONTANA...AND WE WILL BE ON THE BACK SIDE OF THE SURFACE RIDGE AXIS
ASSOCIATED WITH A SURFACE HIGH SLIDING EAST FROM THE CENTRAL PLAINS
TOWARD THE OHIO RIVER VALLEY....WHICH MEANS AN INCREASE IN SOUTHERLY
WINDS IS EXPECTED. WIND SPEEDS ARE FORECAST TO BE AROUND 15-20 MPH
WITH GUSTS OVER 20...AND TEMEPRATURES WILL WARM INTO THE LOW 80S
ONCE AGAIN. MAYBE MORE NOTICEABLY...WILL BE THE DEW POINTS RISING
INTO THE MID 60S BY FRIDAY AFTERNOON.
FOR THE WEEKEND...THE AFOREMENTIONED SYSTEM IN MONTANA WILL BE THE
FEATURE OF CONCERN. THE SURFACE LOW IS EXPECTED TO PROGRESS
EASTWARD ALONG THE INTERNATIONAL BORDER SATURDAY THROUGH
SUNDAY...BUT A NORTH-SOUTH ORIENTED COLD FRONT WILL BE THE FOCUS FOR
SHOWER AND THUNDERSTORM ACTIVITY TO DEVELOP IN OUR AREA...MOST
LIKELY SATURDAY AFTERNOON THROUGH THE OVERNIGHT HOURS. THIS SHOULD
BE A PROGRESSIVE LINE OF THUNDERSTORMS ALONG THE BOUNDARY...SO BY
SUNDAY MORNING WE SHOULD BE BACK IN DRIER NORTHWESTERLY FLOW AND
COOLER TEMEPRATURES. WILL HAVE TO SEE HOW THIS SYSTEM DEVELOPS IN
THE FUTURE MODEL GUIDANCE AS TIMING ISSUES ARE QUITE COMMON THIS FAR
OUT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1259 PM CDT TUE AUG 18 2015
A VERY MESSY TAF PERIOD AS DRY SLOT IS REALLY OVER TAKING AREA
AND LIMITING PRECIPITATION CHANCES FOR THE AFTERNOON AS WELL AS THE
POTENTIAL FOR ANY SEVERE WEATHER LATER. ON TOP OF THAT VERY STRONG
EASTERLY WINDS IN THE 40KT RANGE ACROSS SOUTH CENTRAL MN NOTED EARLY
THIS AFTERNOON AND ARE REFLECTED IN THE KRWF FOR A SHORT PERIOD.
WILL KEEP MENTION OF TSRA IN TAFS FOR THE EARLY AFTERNOON HOURS IN
THE EASTERN PART OF MN AND WESTERN WI BUT CONFIDENCE IS WANING. DO
EXPECT CEILINGS TO REMAIN LOW AND BE AROUND THE 007 TO 012 FOOT
LEVEL DEPENDING ON TIME OF NIGHT AND ANY SUBSEQUENT SHOWER
ACTIVITY. FOR SURE WE CAN EXPECT WEDNESDAY TO BE VERY BREEZY WITH
LOW CLOUDS AND ISOLATED SHOWERS...VERY UNLIKE MID AUGUST AND MORE
LIKE OCTOBER.
KMSP...THE LATEST MODEL TRENDS ARE DECREASING ANY TSRA POTENTIAL
FOR THE LATER AFTERNOON AND EARLY EVENING HOURS AND RADAR IS
SUPPORTING THAT AT THIS POINT IN TIME. WILL KEEP THUNDER IN THE
TEMPO GROUP FOR NOW BUT DO NOT HAVE VERY GOOD CONFIDENCE ON THAT
ACTUALLY HAPPENING. COULD EASILY SEE A TAF AMD. DO EXPECT CEILINGS
TO REMAIN LOW BUT IT MAY SCATTER OUT FROM TIME TO TIME. A WINDY
DAY ON TAP AT MSP TOMORROW WITH A FEW ISOLATED SHOWERS. WIND WILL
BE THE ISSUE WITH AIRFIELD OPS...NOT SHRA.
/OUTLOOK FOR KMSP/
THU...VFR. WINDS W 10-15 KTS.
FRI...VFR. WINDS S 10-15 KTS.
SAT...VFR WITH MVFR/TSRA POSSIBLE LATE. WIND S AT 15G20 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...DRL
LONG TERM...SPD
AVIATION...DRL
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
355 PM CDT TUE AUG 18 2015
.SHORT TERM: (THROUGH LATE TONIGHT)
ISSUED AT 355 PM CDT TUE AUG 18 2015
PREFRONTAL CONVECTION HAS BLOWN UP ABOUT AS EXPECTED THIS AFTERNOON.
SEVERE THUNDERSTORM WATCH IS IN EFFECT UNTIL 900 PM THIS EVENING AND
WE`VE HAD SOME SPORADIC REPORTS OF TREE LIMBS DOWN WITH THE
STRONGEST STORMS. SBCAPE IN EXCESS OF 3000 J/KG INDICATED ON SPC
MESOANALYSIS PAGE AHEAD OF THE CONVECTION WITH A VIGOROUS SHORTWAVE
MOVING INTO WESTERN MISSOURI AT THIS TIME. MASS FIELDS ON SHORT-
RANGE GUIDANCE CONTINUE TO STREAM INSTABILITY UP INTO THE REGION
THROUGH THE EVENING...AND THIS LOOKS REASONABLE GIVEN THE POSITION
OF THE SHORTWAVE AND SURFACE FRONT. HAVE TO SAY, THE HRRR DID A
PRETTY GOOD JOB WITH THE CONVECTION THIS AFTERNOON, SO THE SHORT
RANGE FORECAST FOR TONIGHT IS BIASED HEAVILY TOWARD THE HRRR.
EXPECT STORMS CURRENTLY OVER EASTERN KANSAS TO CONTINUE TO DEVELOP
AND MOVE EASTWARD TONIGHT AHEAD OF THE SHORTWAVE. THERE WILL LIKELY
BE A LUL IN THE THUNDERSTORM ACTIVITY OVER OUR CWFA AFTER 00-02Z,
BUT THE STORMS CURRENTLY IN KANSAS WILL EVENTUALLY MOVE IN AFTER 04-
05Z. ADDITIONAL DEVELOPMENT IS ALSO POSSIBLE AHEAD OF THE KANSAS
STORMS. THE COLD FRONT WILL SWEEP INTO MISSOURI OVERNIGHT AND SHOULD
BE THROUGH CENTRAL AND INTO EASTERN MISSOURI BY 12Z.
CARNEY
.LONG TERM: (WEDNESDAY THROUGH NEXT TUESDAY)
ISSUED AT 355 PM CDT TUE AUG 18 2015
MODELS CONTINUE TO SUPPORT A FAST SURFACE FRONTAL SOLUTION WHILE
MAINTAINING A SIMILAR TIMING WITH THE UPPER LEVEL PROFILE. WHILE
THERE SHOULD STILL BE A NICE SLUG OF WIDESPREAD LIFT BUILDING IN
FROM LATE WEDNESDAY MORNING THRU EARLY EVENING...THE COLUMN WILL
BE VERY LIMITED THERMODYNAMICALLY...MEANING LIKE MOSTLY SHOWERS WITH
DIMINISHING CHANCES FOR THUNDER AS THE DAY GOES ALONG. DECENT RAIN
CHANCES ARE NOW EXPECTED TO LINGER INTO EARLY EVENING BEFORE THEN
MAKING A RAPID EXIT FROM SOUTHWEST TO NORTHEAST FOLLOWED QUICKLY BY
CLEARING SKIES.
WHAT WILL REMAIN IN ITS WAKE WILL BE A RARE COOL AND DRY PERIOD
BEGINNING LATE WEDNESDAY NIGHT THRU FRIDAY AFTERNOON WITH MIN TEMPS
DIPPING INTO THE 50S AND MAX TEMPS ONLY REACHING TO AROUND 80
DEGREES.
THE FRONTAL COMPLEX THAT HAD PUSHED TO OUR SOUTH ON WEDNESDAY
WILL THEN MOVE BACK TO THE NORTH BY SATURDAY TO ALLOW CHANCES FOR
THUNDERSTORMS TO RETURN AND PERSIST THRU THE WEEKEND WITH
TEMPERATURES BACK TO SEASONABLE AVERAGES.
IN YET ANOTHER SIGN THAT AUTUMN IS NOT TOO FAR OFF ANYMORE...ANOTHER
DECENTLY STRONG COLD FRONT PUSHES THRU LATE SUNDAY AND IS
EXPECTED TO BRING AN ENCORE OF THE COOL AND DRY PERIOD FOR MONDAY
AND TUESDAY OF NEXT WEEK.
SOME MODEL DISCREPANCIES THEN EXIST HEADING DEEPER INTO NEXT WEEK
BUT THE GENERAL THEME IS SUMMER THEN REMINDING US THAT IT IS NOT YET
DONE...WITH AN UPPER LEVEL RIDGE ATTEMPTING TO BUILD IN TO POSSIBLY
DELIVER ONE FINAL ROUND OF DANGEROUS HEAT AND HUMIDITY TO CLOSE OUT
AUGUST.
TES
&&
.AVIATION: (FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 641 AM CDT TUE AUG 18 2015
RADIATIONAL FOG WILL REMAIN POSSIBLE AT KSUS AND KCPS THROUGH 14Z,
OTHERWISE VFR FLIGHT CONDITIONS ARE EXPECTED THROUGH MIDDAY.
SCATTERED TO NUMEROUS THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS
AFTERNOON WITH GOOD POTENTIAL FOR IMPACTS AT ALL OF THE TERMINALS.
I HAVE CONSERVATIVELY INTRODUCED TEMPO GROUPS AT ALL OF THE TERMINALS
FOR MVFR FLIGHT CONDITIONS, HOWEVER THE CONDITIONS COULD CERTAINLY
DROP TO IFR WITH GUSTY WINDS. ANOTHER ROUND OF THUNDERSTORMS IS
EXPECTED TO IMPACT THE TERMINALS THIS EVENING AS A COLD FRONT
PUSHES INTO THE AREA.
SPECIFICS FOR KSTL:
VFR FLIGHT CONDITIONS ARE EXPECTED THROUGH MIDDAY. SCATTERED TO
NUMEROUS THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS AFTERNOON
ACROSS EASTERN MO WITH GOOD POTENTIAL FOR IMPACTS AT KSTL. I HAVE
CONSERVATIVELY INTRODUCED A TEMPO GROUP FOR MVFR FLIGHT CONDITIONS,
HOWEVER THE CONDITIONS COULD CERTAINLY DROP TO IFR WITH GUSTY
WINDS. ANOTHER ROUND OF THUNDERSTORMS IS EXPECTED TO IMPACT THE
TERMINAL THIS EVENING AS A COLD FRONT PUSHES INTO THE AREA.
GLASS
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
1246 PM CDT TUE AUG 18 2015
...Updated Aviation Section...
.UPDATE...
Issued at 1246 PM CDT TUE AUG 18 2015
First batch of rain with embedded thunder has made its way into
the western portions of the outlook area. Earlier scattered
activity firing east of Highway 65 has had difficulty sustaining
itself so far, counter to what the HRRR has suggested. Modest
instability ahead of the incoming batch of rain should be more
than enough to sustain the current activity, if not result in an
increase embedded thunderstorm activity. Stronger cells will flirt
with severe limits, with hail to the size of quarters and wind
gusts to 60mph possible. Behind this line of showers/storms, a
brief break in the action is possible late this afternoon into
early this evening, but this should be short lived.
Heading into this evening, the incoming cold front should begin to
light up across Kansas and this will likely pose our best shot at
organized storms given the increase in shear. Still some questions
as to the potential severity of storms given the first batch of
rain moving through could tamper with potential instability. That
said, modest recovery later this afternoon warrants a continued
mention of marginally severe hail/wind.
Cold front comes through tonight and tomorrow will feature a stiff
change in weather conditions. Cloudy, showery and temperatures in
the 60s. An early taste of autumn!
&&
.SHORT TERM...(Today and Tonight)
Issued at 0220 AM CDT TUE AUG 18 2015
More active weather pattern will unfold today into tonight as
upper patten undergoes amplification. A lead impulse will track
eastward from Kansas today as a seasonably deep upper trough digs
into the northern Plains. Expect convection coming out of Kansas
to be on diminishing trend as it spreads eastward into western
Missouri this morning. However expect an increase in coverage of
showers and thunderstorms this afternoon across the Missouri
Ozarks where the lower troposphere can destabilize ahead of the
advancing cloud shield. A few robust updrafts could develop but
the severe risk during the day will be limited due to relatively
weak deep layer shear.
Additional convection will ignite across Kansas into northern
Oklahoma later this afternoon in the wake of the lead impulse and
ahead of the cold front within region of substantial 500 MB height
falls. This activity will spread east southeast into the region
this evening into the overnight hours. This activity will present
at least a marginal risk for severe storms particularly from
southeastern Kansas into central Missouri where the airmass may
recover in the wake of earlier convection. In addition deep layer
shear will increase as the mid level flow increases in response to
the approaching upper level trough.
Overall confidence in this forecast is high.
.LONG TERM...(Wednesday through Monday)
Issued at 0220 AM CDT TUE AUG 18 2015
The cold front will push to the south of the area Wednesday
morning as the upper level trough continues to evolve. The trough
axis will remain to the west much of the day Wednesday with
another shortwave swinging around the base of the trough and into
the region later in the day. This resulting synoptic scale lift
will generate post frontal showers and thunderstorms through much
of the day Wednesday.
The clouds and precipitation along with cool air advection will
result in a much cooler day Wednesday with highs generally in the
60s to lower 70s.
Clearing will take place from west to east Wednesday night as the
upper trough axis swings to the east. A cooler and comfortable
airmass will settle into the area Thursday as surface pressure
builds into the Ozarks.
The upper pattern will become more zonal late week into the
weekend. The chance of convection could return as early as Friday
but more so Friday night and Saturday as a minor shortwave
traverses east across the region.
A northern stream shortwave will push across the northern tier of
the U.S. late in the weekend. This system will drag a cold front
across the region Sunday brining another chance of showers and
thunderstorms.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday Afternoon)
Issued at 1246 PM CDT TUE AUG 18 2015
Challenging forecast over the next 24 hours as there will be
several opportunities for rain/thunder, a cold front passage and
increasing risk of MVFR to IFR ceilings. Line of showers and
embedded thunderstorms will move across the region this afternoon,
with somewhat of a break in the action from later this afternoon
into early this evening. A cold front will then begin to approach
from the northwest this evening, with showers/storms refiring on
this boundary as it moves into the region. Overall, ceilings
should behave with the afternoon/evening activity, with the
potential for MVFR visibility. Cold front passage will be
overnight tonight with rain and perhaps some embedded thunder
spreading into the region heading into Wednesday morning. There is
an increasing risk of IFR ceilings at all sites. MVFR visibility
is possible at SGF/BBG.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
UPDATE...gagan
SHORT TERM...Foster
LONG TERM...Foster
AVIATION...Gagan
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
240 PM CDT TUE AUG 18 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 242 PM CDT TUE AUG 18 2015
FORECAST CHALLENGE FOR TONIGHT IS WHICH HI RES MODEL TO FOLLOW FOR
EVOLUTION OF LOW PRESSURE SYSTEM OVER FAR SERN SD AS IT MOVES
EAST AND THEN NORTH...CLIPPING SOUTHERN AND EASTERN PORTIONS OF
THE CWA. HRRR HAS CONSISTENTLY VERIFIED WITH PLACEMENT OF PRECIP
BEST EACH HOUR...ALTHOUGH EARLIER RUNS THAT SPREAD RAIN AS FAR
NORTH AS FARGO WERE THOUGHT TO BE OVERLY BULLISH AND I HAD FAVORED
THE NMM/ARW...WHICH KEPT PRECIP FURTHER SOUTH WITH THE NE FLOW IN
SFC-H850 LAYER. HOWEVER...15Z HRRR RUN DID A VERY GOOD JOB WITH
PLACEMENT OF PRECIP VERIFIED BY 19Z RADAR IMAGERY. THEREFORE WILL
CONTINUE HRRR TRENDS THROUGH THE EVENING THROUGH 06Z...THEN A FCST
BLEND THROUGH END OF EVENT FOR OUR CWA.
TONIGHT AND TOMORROW...PRECIP OVER SOUTHWEST MN WILL CONTINUE TO
LIFT FROM SW MN INTO W CNTRL MN...HOWEVER WITH SFC LOW MOVING
NE...DO NOT EXPECT RAIN TO LIFT MUCH FURTHER NORTH THAN HILLSBORO
WITHIN THE RRV. LOW BEGINS TO LIFT MORE NORTHWARD AFTER
MIDNIGHT...EVENTUALLY MOVING OVER LAKE SUPERIOR WED AFTN. QUESTION
IS HOW MUCH PRECIP WILL BACK INTO NW MN...AND CURRENT TRENDS ARE
KEEPING MOST OF THE NORTHERN VALLEY AND KITTSON/MARSHALL/NW POLK
COUNTIES DRY. 00Z ECMWF WAS THE FURTHEST WEST AND HAVE DISCOUNTED
IT...PREFERRING A GFS/GEM/NAM BLEND FOR WEDNESDAY POPS. HIGHEST
RAINFALL RATES WITHIN DEFORMATION ZONE SHOULD BE OVER CNTRL
MN...WHERE HPC QPF IS SHOWING UP TO TWO AND A QUARTER INCHES OF
PRECIP WITH A SHARP...DECLINING GRADIENT WESTWARD INTO THE
SOUTHERN VALLEY. CURRENT PRECIP TOTAL THOUGHTS ARE AROUND HALF AN
INCH IN FARGO...LITTLE IF ANY IN GRAND FORKS...RISING TO AROUND 2
INCHES AS FAR EAST AS PARK RAPIDS.
WED NIGHT...SYSTEM PULLS OUT OF LAKE SUPERIOR REGION INTO CNTRL
ONTARIO...SLOWLY PULLING PRECIP OUR OF FAR EAST AND NORTHEASTERN
ZONES BY 12Z THU. CLEARING IN THE WEST...IN ADDITION TO RELAXING
PRESSURE GRADIENT WINDS...WILL ALLOW OVERNIGHT LOWS TO FALL INTO
THE UPPER TO MID 40S ACROSS MOST OF THE REGION...WARMEST IN THE
FAR EAST WHERE CLOUD COVER WILL LINGER OVERNIGHT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 242 PM CDT TUE AUG 18 2015
THURSDAY AND FRIDAY...HIGH PRESSURE MOVES INTO REGION BRINGING
INCREASED SOLAR AND REBOUNDING TEMPERATURES TO NEAR SEASONAL NORMS
ON THURSDAY. RETURN FLOW SETS UP THU NIGHT INTO FRIDAY AND WEAK
SOUTHERLY FLOW THROUGH THE DAY FRIDAY WILL RESULT IN TEMPS
CLIMBING BACK INTO THE MID 80S.
THU NIGHT INTO FRIDAY...PASSING MID LEVEL TROUGH SATURDAY WILL DRAG
ANOTHER COLD FRONT ACROSS THE REGION. TIMING OF FRONT WOULD BRING
BEST T CHANCES ACROSS EASTERN HALF OF THE FA. SUNDAY WILL BE
COOLER FOLLOWED BY MODERATING TEMPERATURES INTO EARLY NEXT WEEK
WITH DRY CONDITIONS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 154 PM CDT TUE AUG 18 2015
MAIN CHALLENGE WILL BE TIMING OF PCPN INTO FAR AND BJI. FAR COULD
SEE SOME SHRA MOVING IN LATE THIS AFTERNOON WITH BEST CHANCES AFT
00Z. OVERALL CIGS HERE SHOULD REMAIN VFR. BJI IN SAME BOAT WITH
HIGHER CONFIDENCE IN STEADIER RAIN AND LOWER CIGS AFT 00Z AND
CONTINUING THROUGH MOST OF THE PERIOD. REMAINDER OF TAF SITES LIKELY
TO MISS OUT ON RAIN WITH VFR MID/UPPER LEVEL CIGS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...SPEICHER
LONG TERM...SPEICHER/VOELKER
AVIATION...VOELKER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
155 PM CDT TUE AUG 18 2015
.UPDATE...
ISSUED AT 154 PM| CDT TUE AUG 18 2015
MORNING UPDATE FOCUS ON POPS FOR THIS AFTERNOON AND TONIGHT AS
LOW PRESSURE SYSTEM EVOLVES IN SD. OVERALL...12Z HRRR VERIFIED
BEST WITH PLACEMENT OF CURRENT PRECIP AND A FINGER OF PRECIP
EXTENDING FROM S CNTRL ND INTO THE JAMESTOWN AREA. HRRR DOES
SPREAD THIS PRECIP NORTH AND EAST...TAKING PRECIP FURTHER NORTH
THAN INHERITED GRIDS. WITH THE NE FLOW I AM AGAINST THIS THINKING
AND WILL MAKE ADJUSTMENTS TO CAPTURE THE PRECIP EXTENDING INTO
THE SW...BUT KEEP LIKELIES SOUTH OF FARGO AND BEMIDJI UNTIL MORE
12Z MODEL DATA HAS CAME IN. FOR AFTN HOURS...PREFER NMM AND ARW
WHICH KEEP PRECIP FURTHER SOUTH (AGAINST BORDERS WITH NEIGHBORING
OFFICES TO THE SOUTH)...BUT WILL SEE HOW 12Z GFS AND CANADIAN
INITIALIZE BEFORE MAKING TOO MANY CHANGES.
UPDATE ISSUED AT 651 AM CDT TUE AUG 18 2015
KJMS NOW REPORTING A SPRINKLE FROM A MID LEVEL CEILING. REGIONAL
RADARS SHOW A THIN BAND OF ECHOES FROM KJMS BACK INTO NORTH
CENTRAL SD. OTHER ECHOES MOVING INTO NORTHEAST SD WHICH MAY TAKE A
WHILE LONGER TO MOVE UP INTO THE SOUTHERN FA. BASICALLY THE
FORECAST REMAINS ON TRACK.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 327 AM CDT TUE AUG 18 2015
MAIN FORECAST CHALLENGE WILL BE THE INTENSE LOW PRESSURE SYSTEM
THAT WILL AFFECT THE AREA TODAY THRU WED/WED NIGHT. AS FOR RIGHT
NOW...SEEING MID AND HIGH LEVEL CLOUDS CONTINUING TO STREAM INTO
THE FA. WINDS STILL ON THE LIGHTER SIDE BUT THEY ARE TRYING TO
TURN MORE NORTHEAST AS THE SFC LOW TAKES SHAPE OVER THE CENTRAL
PLAINS. REGIONAL RADARS SHOW MAIN SWATH OF RAIN MOVING INTO THE
MISSOURI VALLEY OF WEST CENTRAL SD WITH WEAKER ECHOES FINGERING
NORTH INTO SOUTHERN ND. KBIS DID PICK UP A FEW SPRINKLES AND THIS
SAME BAND IS TRYING TO POKE UP TOWARD KJMS. SOME OF THIS MAY
EXTEND INTO THE FAR SW FA BY MORNING BUT IT WOULD ONLY BE VERY
LIGHT. THE SYSTEM SHOULD GET GOING DURING THE DAY TODAY AND
CONTINUE INTO WED/WED NIGHT.
THIS IS AN INTERESTING SYSTEM NO DOUBT BRINGING A WIDER SWATH OF
RAIN TO THE SOUTH AND EAST...GUSTIER WINDS AND COOL TEMPS. WPC
TRACKS THE LOW FROM SOUTH CENTRAL NEBRASKA AT 12Z TUE TO NEAR KMSP
BY 00Z WED...THEN TO NEAR LAKE SUPERIOR BY 12Z WED. THIS MIMICS
THE TRACK OF THE 00Z GFS BEST. HOWEVER OTHER MODELS ARE NOT IN
GOOD AGREEMENT WITH THIS TRACK AND NOT SHOWING THE CONSISTENCY
HOPED FOR AS THE EVENT IS GETTING CLOSER. GLAD THIS IS NOT A
WINTER STORM SYSTEM...AS NAILING DOWN SNOWFALL AMOUNTS WITH SUCH
WIDE MODEL VARIATIONS WOULD BE TOUGH. SINCE THIS WILL BE RAIN THE
MAIN THING IS WHERE THE HEAVIER AMOUNTS FALL. FOR THIS FA...WILL
BE ON THE COOL/NW SIDE OF THE LOW TRACK SO NOT EXPECTING ANY
CONVECTIVE/HEAVIER RAIN AMOUNTS. MOST MODELS GIVING A LONG
DURATION STEADY RAIN IN THE 1 TO 2 INCH RANGE...AND THIS WOULD
MAINLY BE ACROSS THE FAR SOUTHERN RED RIVER VALLEY INTO PORTIONS
OF WEST CENTRAL MN.
00Z ECMWF CAME IN WITH A FURTHER WEST SFC LOW TRACK...FROM SOUTH
CENTRAL NE AT 12Z TUE TO NW IA BY 00Z WED...NEAR KMSP BY 12Z WED
AND THEN UP TO KDLH BY 00Z THU. THIS IS A SLOWER EVOLUTION TOO
WHICH WOULD KEEP THE RAIN/WIND IN LONGER THAN THE WPC SOLUTION.
WILL HAVE TO SEE IF FUTURE RUNS COME INTO BETTER AGREEMENT. EITHER
WAY SINCE IT HAS BEEN DRY HAVE NO HEAVY RAINFALL TYPE HEADLINES.
WINDS WILL BE GUSTY TONIGHT INTO WED ESPECIALLY ACROSS THE MN FA
BUT COULD EXTEND BACK INTO THE RED RIVER VALLEY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 327 AM CDT TUE AUG 18 2015
WRAPAROUND PCPN SHOULD TAPER OFF ACROSS THE EASTERN FA ON WED
NIGHT...ALTHOUGH 00Z ECMWF WOULD HOLD IT THROUGH THU MORNING. THU
HIGHS SHOULD FINALLY REBOUND A LITTLE CLOSER TO MID AUG NORMALS.
FRIDAY TO MONDAY...MODELS IN FAIR AGREEMENT WITH THE BASIC IDEA OF A
WARM START TO THE WEEKEND WITH A SHORT WAVE AND FROPA BRINGING
THUNDER ACTIVITY TO THE ENTIRE CWFA THEN COOLING TEMPS DOWN IN ITS
WAKE. TIMING UNCERTAINTY REMAINS...CURRENT THINKING IS THAT SATURDAY
DAYTIME FROPA IS EXPECTED...WITH THE GFS A BIT FASTER IN THE SYSTEMS
PROGRESSION THAN THE ECMWF. SUNDAY MAY SEE AM SHOWERS IF THE SYSTEM
IS AS SLOW AS THE EC THEN DRY ON MONDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 154 PM CDT TUE AUG 18 2015
MAIN CHALLENGE WILL BE TIMING OF PCPN INTO FAR AND BJI. FAR COULD
SEE SOME SHRA MOVING IN LATE THIS AFTERNOON WITH BEST CHANCES AFT
00Z. OVERALL CIGS HERE SHOULD REMAIN VFR. BJI IN SAME BOAT WITH
HIGHER CONFIDENCE IN STEADIER RAIN AND LOWER CIGS AFT 00Z AND
CONTINUING THROUGH MOST OF THE PERIOD. REMAINDER OF TAF SITES LIKELY
TO MISS OUT ON RAIN WITH VFR MID/UPPER LEVEL CIGS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...SPEICHER
SHORT TERM...GODON
LONG TERM...GODON/JK
AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1235 PM CDT TUE AUG 18 2015
.AVIATION...
INITIAL COLD FRONT ALREADY INTO THE NWRN TX PANHANDLE WITH A
STRONGER NORTHERLY PUSH BACK OVER NERN COLO...NWRN KS...AND SWRN
NEBR. THIS FRONT IS EXPECTED TO BE THE FOCUS FOR TS DEVELOPMENT
LATER THIS AFTN ACROSS THE PANHANDLES THEN SHIFTING EWD INTO WRN
OKLA. KCDS WILL SEE THE BEST CHANCE FOR SOME OF THIS ACTIVITY WITH
KPVW SECOND AND KLBB A DISTANT THIRD. PEAK CHANCE COMES BTWN 00Z
AND 06Z. WILL THUS LEAVE TEMPO OUT ATTM AND LET NEXT SHIFT
REEVALUATE WITH THE 00Z TAF SET. ONLY OTHER ISSUES ARE GOOD
POTENTIAL FOR NORTH TO NE WINDS TO BECOME A BIT GUSTY BEHIND THE
FRONT NEAR SUNRISE WEDNESDAY AND A VERY SMALL CHANCE OF MVFR CIGS
DEVELOPING BEHIND THE FRONT WEDNESDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 653 AM CDT TUE AUG 18 2015/
UPDATE...
SHOWER AND T-STORM ACTIVITY ALONG THE TX-NM STATE LINE HAS
GRADUALLY CONGEALED INTO A BROAD BLOB OF MAINLY LIGHT RAIN...BUT
WITH A FEW EMBEDDED T-STORMS...MAINLY OVER COCHRAN AND YOAKUM
COUNTIES. WE HAVE UPPED POPS CONSIDERABLY IN THIS AREA FOR THE
MORNING HOURS. ELSEWHERE...SOME ADDITIONAL DEVELOPMENT IS NOTED
ACROSS FLOYD AND BRISCOE COUNTIES...BUT WE HAVE KEPT THE ISOLATED
MENTION IN PLACE FOR NOW.
AVIATION...
SCATTERED -SHRA AND MORE ISOLATED -TSRA COULD AFFECT ANY OF THE
TERMINALS THROUGH 15 OR 16 UTC. WE HAVE GONE AHEAD AND ADDED TEMPO
GROUPS AT KLBB AND KPVW TO COVER THIS POTENTIAL. TSRA WILL THEN RETURN
TO THE FORECAST THIS EVENING AS A COLD FRONT MOVES IN FROM THE
NORTH. AT THIS TIME...CONFIDENCE IS TOO LOW IN THE TIMING AND
COVERAGE OF TSRA TO INCLUDE IN THE FORECASTS. ALSO...THE EXACT
TIME OF THE FROPA THROUGH THE TERMINALS REMAINS UNCERTAIN DUE TO
POSSIBLE INTERACTION WITH T-STORM OUTFLOWS.
PREV DISCUSSION... /ISSUED 402 AM CDT TUE AUG 18 2015/
SHORT TERM...
WATER VAPOR IMAGERY SHOWS A SHARP SHORTWAVE TROUGH CROSSING THE
ROCKIES AND EMERGING OVER THE CENTRAL AND NRN PLAINS THIS MORNING.
THIS IS PRODUCING SCATTERED CONVECTIVE ACTIVITY FROM
NEBRASKA...ARCING EAST INTO CENTRAL KS...THEN BACK SW ACROSS NW OKLA
AND ERN TX PANHANDLE...AND INTO ERN AND SRN NEW MEXICO. THIS
ACTIVITY IS MOSTLY SPLITTING OUR FORECAST AREA AT 3 AM...WITH THE
EASTERN BATCH JUST NICKING OUR NE COUNTIES AND THE WESTERN BATCH
STAYING WEST OF THE STATE LINE. HOWEVER...RADAR IS SHOWING A SLIGHT
UPTICK IN COVERAGE AND INTENSITY AT THIS TIME...AND THE HRRR AND RAP
SUGGEST THAT ISOLATED TO SCATTERED COVERAGE OF SHOWERS AND STORMS
WILL WORK THEIR WAY SEWD ACROSS MOST OF OUR FORECAST AREA THIS
MORNING. THE ACTIVITY WILL TEND TO WANE TOWARD SUNRISE...AND AT
THIS TIME IT LOOKS LIKE AN ISOLATED MENTION IN THE FORECAST AFTER
12 UTC WILL BE SUFFICIENT.
IT NOW APPEARS THAT MOST OF THE DAY WILL BE PRETTY QUIET AS MODEST
SUBSIDENCE REPLACES THE MODEST LIFT MOVING THROUGH THIS MORNING.
THIS SHOULD ALLOW TEMPS TO WARM A FEW DEGREES FROM YESTERDAY/S
READINGS WITH HIGHS EXPECTED TO TOP OUT IN THE LOWER 90S NORTHWEST
TO NEAR 100 IN THE SOUTHEAST. MEANWHILE...THE MUCH ANTICIPATED COLD
FRONT....CURRENTLY MOVING THROUGH ERN COLO AND WRN KS...WILL BE
MAKING IT/S WAY SOUTH THROUGH THE PANHANDLES. THE LATEST HIGH-RES
GUIDANCE IS IN GOOD AGREEMENT THAT AN INITIAL WIND SHIFT WILL WORK
INTO THE FAR SW TX PANHANDLE AND NW SPLNS BY EARLY AFTERNOON...BUT
THEN NOT MAKE MUCH ADDITIONAL PROGRESS THROUGH EARLY EVENING. THIS
WILL SET UP A SURFACE TROUGH RUNNING FROM THE WRN SOUTH PLAINS
INTO THE SRN TX PANHANDLE. DESPITE A NICE BUILDUP OF CAPE TO NEAR
3000 J/KG IN THIS AREA...THE CAP IS EXPECTED TO HOLD THROUGH MOST
OF THE AFTERNOON. LARGE-SCALE ASCENT SHOULD BEGIN TO INCREASE
EARLY THIS EVENING AS THE NEXT VORT MAX SWINGS ACROSS THE SRN
ROCKIES. ALTHOUGH THE BULK OF THIS LIFT WILL BE OFF TO OUR
NORTH...IT SHOULD TRIGGER SOME T-STORM DEVELOPMENT AS IT SPREADS
OVER THE FRONT AND SURFACE TROUGH. UNFORTUNATELY...MODEL GUIDANCE
REMAINS HIGHLY VARIABLE AND INCONSISTENT IN THE PLACEMENT AND
COVERAGE OF QPF AND MODEL REFLECTIVITY FIELDS...INCLUDING A FEW
SOLUTIONS...SUCH AS THE 00 UTC TTU-WRF...WHICH KEEPS THE FORECAST
AREA MOSTLY PRECIP FREE. AS SUCH...OUR CONFIDENCE REMAINS LOW
REGARDS THE EXTENT OF THUNDERSTORMS THIS EVENING AND THUS POPS ARE
ONLY IN THE 20 TO 40 PERCENT RANGE....MAXIMIZED ACROSS THE FAR SE
TX PANHANDLE. THE AVAILABLE INSTABILITY AND DEEP-LAYER SHEAR
SUPPORT THE IDEA OF SOME STORM ORGANIZATION AND A SEVERE WEATHER
THREAT...FOCUSED ON THE FAR SRN TX PANHANDLE AND NW
SPLNS...ALTHOUGH THE COVERAGE MAY BE JUST TOO LIMITED TO BE OF
SIGNIFICANT IMPACT.
THE COLD FRONT WILL SURGE THROUGH THE FORECAST AREA OVERNIGHT...WITH
BREEZY NE WINDS EXPECTED WITH THE FROPA EVEN OUTSIDE OF ANY T-STORM
ACTIVITY. LOW STRATUS WILL ALSO EXPAND IN COVERAGE BEHIND THE FRONT.
THE BEST RAIN CHANCES WILL GRADUALLY SHIFT EWD INTO THE ROLLING
PLAINS EARLY WEDNESDAY MORNING.
LONG TERM...
MUCH COOLER AIR WILL BE ADVECTING INTO THE SOUTH PLAINS ON GUSTY
NORTHEASTERLY WINDS WEDNESDAY BEHIND THE EARLY DAY FROPA. SUSTAINED
WINDS NEAR 20 KNOTS COUPLED WITH HIGHS ONLY CLIMBING INTO THE 70S
FOR MOST SPOTS WILL MAKE FOR A FALL-LIKE FEEL IN THE AIR. IN
ADDITION...MOIST UPGLIDE ABOVE THE FRONTAL ZONE WILL YIELD A STRATUS
DECK WITH ENOUGH ELEVATED INSTABILITY PERHAPS SUPPORTING A RISK OF A
FEW SHOWERS/STORMS ACROSS THE EASTERN AND SOUTHEASTERN ZONES. OF
NOTE...THE RECORD MINIMUM HIGH FOR AUGUST 19TH IN LUBBOCK IS 74
DEGREES /SET IN 1956/ AND THIS COULD BE THREATENED IF CLOUDS HANG
TOUGH ALL DAY. SURFACE RIDGING WILL THEN SETTLE OVER THE REGION WITH
LIGHT WINDS AND THE COOLEST AIR SINCE LATE MAY. DEPENDING ON WHETHER
SKIES COMPLETELY CLEAR AND EXACTLY HOW LOW DEWPOINTS CAN DROP WITHIN
THE RIDGE...WE COULD ALSO THREATEN THE RECORD LOW THURSDAY MORNING
/THE CURRENT RECORD IS 54 DEGREES SET IN 1915/.
THE SURFACE RIDGE WILL SLIDE EASTWARD ON THURSDAY ALLOWING SOUTHERLY
WINDS TO GRADUALLY RETURN AND COUPLED WITH INCREASED INSOLATION
HIGHS WILL REBOUND BACK INTO THE 80S. WE WILL THEN SEE SLIM STORM
CHANCES CREEP BACK INTO THE FORECAST THURSDAY NIGHT INTO FRIDAY AS
ONE OR MORE SUBTLE DISTURBANCES MOVE THROUGH THE QUASI-ZONAL FLOW
AND GRAZE THE AREA FROM THE NORTH. THE SUPPRESSED SOUTHWESTERN UPPER
RIDGE IS THEN FORECAST TO EXPAND NORTHWARD AND BRIDGE TO AN UPPER
HIGH CENTERED OVER FLORID THIS WEEKEND WHILE AT THE SAME TIME A
SHARP TROUGH MOVES STEADILY ACROSS THE NORTHERN TIER OF THE
NATION. THE BUILDING HEIGHTS AND PROLONGED SOUTHERLY FLOW WILL
ALLOW TEMPERATURES TO MODERATE BACK UP TO NEAR AVERAGE BY FRIDAY
AND SATURDAY. EVEN WITH THE RIDGE BUILDING MORE SQUARELY
OVERHEAD...A SUBTROPICAL MOISTURE FETCH ALONG WITH CONVERGENCE
ALONG A SURFACE TROUGH WILL KEEP LOW THUNDER CHANCES GOING ACROSS
THE WESTERN ZONES ON SATURDAY. THE NORTHERN STREAM SYSTEM WILL
THEN SEND A COLD FRONT SOUTHWARD INTO THE SOUTHERN PLAINS ON
SUNDAY BEFORE STALLING OUT SOMEWHERE NEARBY AND THEN WASHING OUT
EARLY NEXT WEEK. THIS FRONT WILL PROVIDE AT LEAST A SLIM SHOT OF
ADDITIONAL CONVECTION ON SUNDAY...THOUGH WITHOUT ANY UPPER SUPPORT
COVERAGE WOULD LIKELY BE NO BETTER THAN SCATTERED.
AFTER ANOTHER BRIEF AND LESS DRAMATIC COOL DOWN /THAN ON
WEDNESDAY/ WITH THE FRONT LATE THIS WEEKEND...HOTTER AND DRY
WEATHER SHOULD FOLLOW. THIS WILL OCCUR AS UPPER RIDGING IS
PROGGED TO AMPLIFY OVER THE SOUTHERN ROCKIES INTO THE SOUTHERN
HIGH PLAINS DURING THE EARLY AND MIDDLE PARTS OF NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 92 58 75 53 / 20 30 10 0
TULIA 91 60 74 54 / 10 40 20 0
PLAINVIEW 92 61 74 53 / 10 30 20 0
LEVELLAND 93 63 77 56 / 10 30 20 0
LUBBOCK 94 65 77 57 / 10 30 20 10
DENVER CITY 96 65 79 56 / 10 20 20 10
BROWNFIELD 94 65 79 56 / 10 30 20 10
CHILDRESS 96 67 78 58 / 20 40 30 10
SPUR 95 67 78 58 / 10 30 30 20
ASPERMONT 99 70 83 61 / 10 30 30 30
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
339 PM CDT TUE AUG 18 2015
.SHORT TERM...
.THIS EVENING...FORECAST CONFIDENCE HIGH.
A STRENGTHENING UPPER LOW OVER THE NORTHERN PLAINS IS PRODUCING
ONGOING SHOWERS AND THUNDERSTORMS OVER MN AND IA TODAY. THERE ARE A
LOT OF CLOUDS ASSOCIATED WITH THAT AND AN 850MB WARM FRONT OVER
NORTHERN WISCONSIN. SOUTHEAST WI IS SEEING A FEW BREAKS IN THE
CLOUDS TODAY WHICH IS HELPING TO INCREASE TEMPS TO AROUND 80 AND
BUILD CAPE TO AROUND 1000 J/KG.
A STRONG SHORTWAVE TROUGH CURRENTLY OVER NORTHEAST MO WILL MOVE UP
THROUGH IA AND WI LATE THIS AFTERNOON/EVENING. THE NOSE OF THE LOW
LEVEL JET /LLJ/ WILL LIFT UP TO THE WI/IL BORDER THIS AFTERNOON AND
LIKELY INTO SOUTH CENTRAL WI BEFORE SHIFTING EAST THIS EVENING. THE
CONVECTION OVER FAR WESTERN WI AND FAR EASTERN IOWA IS TRACKING NNE.
THE 19Z HRRR MODEL PICKED UP ON IT AND BRINGS A WEAKER VERSION OF IT
INTO MADISON AFTER 5 PM. IT STILL HAS THE MAIN CONVECTIVE LINE WITH
THE STRONG SHORTWAVE REACHING MADISON AROUND 01Z /8 PM. WE CANNOT
DISCOUNT THIS LATEST RUN AS IT MAY BE ON TO SOMETHING FOR HOW THIS
EVENING/S CONVECTION WILL EVOLVE.
A NW TO SE ORIENTED LINE OF THUNDERSTORMS IS PORTRAYED BY THE OTHER
CONVECTIVE ALLOWING MODELS /CAMS/. THEY LIFT IT NORTHEAST THROUGH
SOUTHERN AND EAST CENTRAL WI THIS EVENING. IT SHOULD REACH MADISON
BY 7 PM AND MILWAUKEE BY 9 PM. THE THUNDERSTORMS SHOULD BE OUT OF
SOUTHERN WI BY MIDNIGHT.
THE SHEAR WILL BE STRONG OVER SOUTH CENTRAL WI AS THE SHORTWAVE
ARRIVES. THE CAPE IS MODERATE NOW... BUT WILL BE LOWER THIS EVENING
DUE TO WARM AIR ADVECTION ALOFT AND SUBSEQUENT VERY WEAK MID LEVEL
LAPSE RATES. STILL... THERE MAY BE ENOUGH SHEAR TO DEVELOP A FEW
SUSTAINED UPDRAFTS THAT COULD PRODUCE LOW LEVEL MESOCYCLONES AND A
POSSIBLE TORNADO. THE TORNADO WATCH WAS ISSUED ALREADY THIS
AFTERNOON AND IT IS IN EFFECT UNTIL 10 PM FOR ALL BUT THE EASTERN
FORECAST AREA. THE MAIN THREAT FOR SEVERE STORMS IN SOUTH CENTRAL WI
IS NOT UNTIL AFTER 5 PM.
.OVERNIGHT AND WEDNESDAY...FORECAST CONFIDENCE HIGH.
THE SURFACE LOW WILL TRACK NORTH FROM WEST CENTRAL WI TO WESTERN
LAKE SUPERIOR ON WEDNESDAY. THIS WILL RESULT IN A STRONG PRESSURE
GRADIENT OVER SOUTHERN WISCONSIN AND GUSTY SOUTHWEST WINDS BEGINNING
EARLY WEDNESDAY MORNING. STEEP LOW LEVEL LAPSE RATES WILL LEAD TO
EXTENSIVE DIURNAL CUMULUS CLOUDS SO KEPT MAX TEMPS ON THE LOWER END
OF GUIDANCE.
&&
.WEDNESDAY NIGHT AND THURSDAY...FORECAST CONFIDENCE...HIGH
THE GFS BRINGS A CLOSED MID/UPPER LOW ACROSS LAKE SUPERIOR
WEDNESDAY NIGHT AS THE TROUGH AXIS EXITS FAR EASTERN WISCONSIN
TOWARDS SUNRISE. THE CLOSED LOW LIFTS INTO SOUTHERN CANADA
THURSDAY.
THE 850/700 MB RH INCREASES OVER SOUTH CENTRAL WISCONSIN EARLY
WEDNESDAY EVENING...AND OVER MUCH OF THE SOUTH WEDNESDAY NIGHT
WITH THE EDGE OF THE HIGHER RH NEAR THE ILLINOIS BORDER AREA. THIS
SHOULD BRING AN AREA OF CUMULUS/STRATOCUMULUS ACROSS MUCH OF THE
FORECAST AREA WEDNESDAY NIGHT THAT LIFTS NORTHEAST LASTER
THURSDAY.
THE WRAP AROUND PRECIPITATION MAINLY STAYS NORTHWEST OF THE
FORECAST AREA. HOWEVER LOW LEVEL LAPSE RATES ARE FAIRLY STEEP SO
AN ISLOATED SHOWER COULD FORM THURSDAY.
WEST WINDS WILL BE BRISK AND WITH THE STEEP LAPSE RATES...GUSTS
TO 30 MPH IS POSSIBLE.
.THURSDAY NIGHT AND FRIDAY...FORECAST CONFIDENCE...HIGH
A ZONAL FLOW AGAIN BRIEFLY DEVELOPS IN THE MID/UPPER LEVELS
ACROSS WISCONSIN WITH THE MAIN JET ACROSS SOUTHERN CANADA. ANOTHER
SHORTWAVE DROPS INTO THE NORTHERN ROCKIES LATE FRIDAY.
THE NAM...GFS AND ECMWF ARE DRY.
.LONG TERM...
.FRIDAY NIGHT AND SATURDAY...FORECAST CONFIDENCE...HIGH
THE MID/UPPER TROUGH EXITS THE NORTHERN ROCKIES AND MOVES INTO THE
NORTHERN PLAINS WITH A WEAK RIDGE OVER SOUTHERN WISCONSIN.
BOTH THE 12Z GFS AND 00Z ECMWF KEEP A LOW OVER THE PLAINS WITH
PRECIPITATION STILL WELL OFF TO THE WEST.
.SUNDAY...FORECAST CONFIDENCE...MEDIUM
THE SHORTWAVE REACHES THE UPPER MISSISSIPPI VALLEY SUNDAY. THE
GFS IS JUST A LITTLE FARTHER NORTH AND SLIGHTLY SLOWER WITH THE
SHORTWAVE.
THE SURFACE LOW MOVES TO JUST NORTH OF LAKE SUPERIOR WITH A BAND
OF MODERATE PRECIPITATION WITH A TRAILING COLD FRONT.
.MONDAY...FORECAST CONFIDENCE...MEDIUM
THE SHORTWAVE MOVES ACROSS THE UPPER GREAT LAKES SUNDAY NIGHT AND
PUSHES IT NORTHEAST. THE 00Z ECMWF CUTS OFF THE LOW NEAR LAKE
SUPERIOR AND LAGS THE TROUGH INTO THE GREAT LAKES INTO MONDAY.
THE 00Z ECMWF HAS LOW PRESSURE REMAINING OVER THE UPPER GREAT
LAKES INTO MONDAY WITH THE HIGH OVER THE EASTERN PLAINS AND
WESTERN MISSISSIPPI VALLEY AREA...WHILE THE GFS BRINGS THE HIGH
ACROSS WISCONSIN.
&&
.AVIATION/00Z TAFS/...
EXPECT A NW TO SE ORIENTED LINE OF THUNDERSTORMS TO LIFT NORTHEAST
THROUGH SOUTHERN WI THIS EVENING. IT SHOULD ARRIVE IN MSN BY 6 PM
AND MKE BY 8 PM. THUNDERSTORMS COULD CONTAIN STRONG WIND GUSTS AND
SMALL HAIL. THERE IS ALSO A RISK FOR A TORNADO IN SOUTH CENTRAL WI.
ALL CONVECTION SHOULD BE OUT OF SOUTHERN WI BY MIDNIGHT. LOW CIGS
ARE POSSIBLE OVERNIGHT. EXPECT GUSTY SOUTHWEST WINDS ON WEDNESDAY AS
STRONG LOW PRESSURE TRACKS ACROSS NORTHWEST WI.
&&
.MARINE...
LOW PRESSURE WILL TRACK FROM WEST CENTRAL WISCONSIN TO WESTERN LAKE
SUPERIOR ON WEDNESDAY. EXPECT GUSTY SOUTHWEST WINDS BEGINNING EARLY
WEDNESDAY MORNING THAT CONTINUE THROUGH THURSDAY AFTERNOON. A SMALL
CRAFT ADVISORY IS IN EFFECT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TONIGHT/WEDNESDAY AND AVIATION/MARINE...MRC
WEDNESDAY NIGHT THROUGH TUESDAY...HENTZ
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1229 PM CDT TUE AUG 18 2015
UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE
.SHORT TERM...TODAY...TONIGHT...AND WEDNESDAY
ISSUED AT 316 AM CDT TUE AUG 18 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A COLD
FRONT STRETCHING ACROSS SOUTHWEST TO EAST-CENTRAL WISCONSIN EARLY
THIS MORNING. A SECONDARY FRONT RUNS ACROSS SOUTHERN MINNESOTA TO
EASTERN LAKE SUPERIOR. WEAK FGEN COMBINED WITH LINGERING ELEVATED
INSTABILITY CONTINUE TO GENERATE SCATTERED SHOWERS ALONG BOTH
FRONTS. BETTER MOISTURE AND INSTABILITY RESIDES OVER IOWA AND THE
PLAINS WHERE THUNDERSTORMS ARE OCCURRING. LOOKING FURTHER
UPSTREAM...LOW PRESSURE IS DEVELOPING OVER NORTHEAST COLORADO AHEAD
OF A DIGGING SHORTWAVE TROUGH. PRECIP TRENDS ALONG THE FRONT AND
ASSOCIATED WITH THE SURFACE LOW ARE THE MAIN FORECAST CONCERNS.
MODELS HAVE SLOWED DOWN THE PROGRESSION OF SURFACE FEATURES
SOMEWHAT. THE GFS IS A CLEAR OUTLIER...PROBABLY DUE TO ITS RATHER
POOR INITIALIZATION. PREFER A BLEND OF THE NAM/ECMWF/GEM.
TODAY...AS LOW PRESSURE CONSOLIDATES OVER THE CENTRAL PLAINS...THE
PRIMARY COLD FRONT IS PROJECTED TO STALL OVER CENTRAL AND EAST-
CENTRAL WISCONSIN...NEAR OR JUST SOUTH OF THE SOUTHERN FORECAST AREA
BORDER. WILL PROBABLY SEE AN UPTICK OF SHOWER ACTIVITY THIS MORNING
WITH WEAK SHORTWAVES MOVING OVERHEAD. ONCE THESE SHORTWAVES PASS TO
THE EAST BY LATE MORNING...NORTHERN WISCONSIN MAY SEE A DRY PERIOD
SO REDUCED PRECIP CHANCES THERE. SCATTERED SHOWERS WILL STILL IMPACT
THE SOUTH...CLOSER TO THE STALLED FRONT. WILL LIKELY SEE SHOWERS AND
A FEW STORMS BECOME MORE WIDESPREAD OVER CENTRAL WISCONSIN LATE IN
THE AFTERNOON AS MID-LEVEL FLOW STRENGTHENS OVER THE BOUNDARY.
HIGHS RANGING FROM THE MID 60S NORTH TO MID 70S SOUTH.
TONIGHT...A STRONG AREA OF LOW PRESSURE WILL LIFT NORTHEAST TOWARDS
MINNEAPOLIS WHILE PUSHING A COLD FRONT INTO SOUTHWEST OR CENTRAL
WISCONSIN BY 12Z WED. AS LARGE-SCALE ASCENT INCREASES...SHOULD SEE
AREAS OF SHOWERS AND THUNDERSTORMS LIFT NORTHEAST ACROSS THE
FORECAST AREA. THE MOST POTENT SWATH OF STORMS SHOULD ARRIVE LATE
IN THE NIGHT AHEAD OF THE COLD FRONT AND CLOSED MID-LEVEL
CIRCULATION. THOUGH INSTABILITY WILL BE QUITE LOW...PWATS WILL BE
GREATER THAN 1.5 INCHES AND FORCING WILL BE EXCELLENT. WIND FIELDS
ALOFT WILL ALSO BE STRENGTHENING AS 850MB WINDS APPROACH 40-45 KTS.
THOUGH CONVECTION WILL LIKELY BE LOW TOPPED...ANY CONVECTION WILL BE
CAPABLE OF BRINGING DOWN THESE STRONGER WINDS. THEREFORE...A
MARGINAL RISK LOOKS REASONABLE FOR THE SOUTHWEST FORECAST AREA.
TEMPS WILL NOT FALL MUCH TONIGHT. LOWS AROUND 60 NORTH TO THE MID
60S SOUTH.
WEDNESDAY...LOW PRESSURE WILL SLOWLY MOVE NORTHEAST OVER FAR
NORTHWEST WISCONSIN AS THE COLD FRONT SWEEPS ACROSS NORTH-CENTRAL
AND NORTHEAST WISCONSIN. SHOWERS AND STORMS ARE A DECENT BET AHEAD
OF THE FRONT DURING THE MORNING...AND THE THREAT OF STRONG GUSTY
WINDS WILL ACCOMPANY ANY STORMS. THE FRONT WILL EXIT NORTHEAST
WISCONSIN BY MID TO LATE AFTERNOON ENDING ANY STORM THREAT. WRAP
AROUND LIGHT SHOWERS MAY SPREAD INTO NORTH-CENTRAL WISCONSIN BY
EARLY EVENING. HIGHS RANGING FROM THE MID 60S WEST TO MID 70S EAST.
.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY
ISSUED AT 316 AM CDT TUE AUG 18 2015
THE STRONG COLD FRONT AND UPPER LEVEL CYCLONE...THAT WILL IMPACT
THE AREA IN THE SHORT TERM...WILL DEPART THE REGION ON THEIR WAY
TOWARD HUDSON BAY DURING THE LATTER HALF OF THE WEEK. THE CHANCE
FOR RAIN WILL DECREASE AS THESE FEATURES DEPART...ENDING BY 00Z
FRIDAY. UPPER FLOW ACROSS THE REGION BRIEFLY BECOMES ZONAL...THEN
SOUTHWEST AS A WEST COAST TROUGH TRAVERSES THE CONUS. ANOTHER
COLD FRONT IS FORECAST TO MOVE ACROSS THE REGION OVER THE WEEKEND
ALONG WITH THE TROUGH. THIS WILL BRING CHANCES FOR THUNDERSTORMS
BACK TO THE AREA FROM SATURDAY NIGHT THROUGH SUNDAY NIGHT.
COLDER THAN NORMAL TEMPERATURES CAN BE EXPECTED THURSDAY BEFORE
FLOW ALOFT FLATTENS AND WARMER THAN NORMAL CONDITIONS RETURN FOR
FRIDAY AND SATURDAY. CLOUDS AND RAIN WILL KEEP HIGHS CLOSER TO
NORMAL ON SUNDAY. EXPECT COLDER THAN NORMAL TEMPERATURES ON MONDAY
BEHIND THE COLD FRONT.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1217 PM CDT TUE AUG 18 2015
FRONT CONTINUES TO LINGER SOUTH OF A WAUTOMA TO OSHKOSH TO
MANITOWOC LINE. THIS AREA WILL BE THE FOCUS FOR SCATTERED
THUNDERSTORM ACTIVITY THIS AFTERNOON AS TEMPERATURES WERE
NOW WARMING INTO THE MIDDLE TO UPPER 70S ALONG AND JUST SOUTH
OF THE FRONT. HAVE ADDED THUNDERSTORMS IN THE 18Z TAFS AT
KGRB/KATW. WILL MAKE A LAST MINUTE DECISION ON ADDING THEM TO
KMTW. OTHERWISE...IFR/MVFR CIGS CONTINUE ACROSS MUCH OF CENTRAL
INTO PORTIONS OF NORTH-CENTRAL AND FAR NORTHEAST WISCONSIN EARLY
THIS AFTERNOON. VFR CONDITIONS ALSO NOTED FROM KRHI NORTH INTO
VILAS COUNTY. SOME IMPROVEMENT SHOULD BE SEEN THIS AFTERNOON WHERE
THE IFR/MVFR CONDITIONS EXIST. FOR TONIGHT...A SIGNIFICANT ROUND
OF RAIN AND THUNDERSTORMS IS EXPECTED WITH UNUSUALLY STRONG SYSTEM
MOVES INTO THE UPPER MIDWEST/WESTERN GREAT LAKES REGION ON WEDNESDAY.
ONE THE MAIN ROUND OF RAIN MOVES OUT LATER TONIGHT...THERE IS SOME
POTENTIAL FOR A LINE OF SHOWERS TO REDEVELOP...MAINLY FROM 13Z TO
17Z AS THE LINE OF SHOWERS WILL RACE NORTHEAST. THIS LINE OF
SHOWERS COULD POSSIBLY PRODUCE STRONG GUSTY WINDS TO AROUND 40
KNOTS.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......MG
AVIATION.......ECKBERG