Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/28/13
AREA FORECAST DISCUSSION
NWS SAN JOAQUIN VALLEY - HANFORD CA
534 PM PDT TUE AUG 27 2013
.SYNOPSIS...
A MOIST AIRFLOW CONTINUES OVER THE REGION INCREASING THE CHANCES
OF AFTERNOON AND EVENING THUNDERSTORMS PRIMARILY OVER THE KERN
COUNTY DESERT AND MOUNTAIN AREAS AND OVER THE SIERRA NEVADA CREST
AREAS THIS WEEK.
&&
.DISCUSSION...
CANCELLED THE FLASH FLOOD WATCH FOR THE REMAINDER OF THIS EVENING.
THUS FAR TODAY STORMS HAVE REALLY STRUGGLED TO GET GOING. LOOKING
AT SPC MESO PAGE AND OBS EVIDENT THAT INSTABILITY IS JUST NOT
THERE...DESPITE A WEAK SHORT WAVE MOVING NORTH OUT OF SOUTHERN
CALIFORNIA THIS AFTERNOON. STORMS HAVE STRUGGLED TO ATTAIN HEIGHTS
MUCH ABOVE 20KFT AND LITTLE CC/CG LIGHTNING HAS BEEN NOTED. IN
ADDITION...STORM MOTION PER CORFIDI VECTORS ARE A HEALTHY
15-20KTS...A BIT FASTER THAN I/D LIKE TO SEE FOR A SIGNIFICANT
FLASH FLOOD THREAT. ANOTHER NAIL IN THE WATCH COFFIN IS RECENT
RUNS OF THE HRRR HAVE FAILED TO GENERATE MUCH IN THE WAY OF
LOCALIZED HEAVY RAIN. POPS WERE ALSO ADJUSTED DOWNWARD FOR THE
REMAINDER OF THE EVENING.
&&
.PREV DISC... /ISSUED 244 PM PDT TUE AUG 27 2013/
DISCUSSION...
REALLY NO BIG CHANGE IN THE SYNOPTIC PATTERN OVER THE NEXT
SEVERAL DAYS WITH THE TROUGH OF LOW PRESSURE REMAINING OFF THE
WEST COAST AS A LARGE HIGH PRESSURE CELL ANCHORED OVER THE CENTRAL
US. THE MAIN FORECASTING PROBLEM OVER THE NEXT FEW DAYS IS THE
TIMING AND EXTENT OF ANY DISTURBANCES MOVING UNDER THE RIDGE AND
INTO CALIFORNIA FROM THE SOUTHEAST. LATEST NAM12 MODEL BRINGS A
SURGE OF ADDITIONAL MOISTURE INTO KERN COUNTY ON THURSDAY WHILE
OTHER MODELS AREA NOT AT THIS TIME. CURRENT FORECAST HAS SLIGHT
CHANCE POPS OVER KERN COUNTY AND THE SIERRA AND THIS SEEMS OKAY
FOR NOW.
THE FORECAST FOR THE LABOR DAY WEEKEND IS A BIT MORE TRICKY AS
PREVIOUS MODEL CONSENSUS BROUGHT A DEEP TROUGH TO THE WEST OF
CALIFORNIA AND AN ASSOCIATED INCREASE IN DRY SOUTHWEST FLOW. THIS
WOULD HAVE EFFECTIVELY ENDED ANY THUNDERSTORM THREAT OVER CENTRAL
CALIFORNIA. NOW THE ECMWF AND THE LATEST GFS ARE NOT NEARLY AS
DEEP WITH THE TROUGH SOLUTION PROJECT ANOTHER INTRUSION OF
MOISTURE FROM THE SOUTHEAST WITH THE ECMWF BRINGING AN EASTERLY
WAVE AND VORTICITY CENTER INTO CENTRAL CALIFORNIA. EITHER SOLUTION
PUTS THE KIBOSH ON A BIG COOLDOWN. I HAVE RAISED TEMPERATURES SOME
AND HAVE REINTRODUCED THUNDERSTORMS ON SATURDAY WITH SUNDAY YET TO
BE SEEN FOR CHANGES.
&&
.AVIATION...
AREAS OF SMOKE POSSIBLE IN MARIPOSA COUNTY AND YOSEMITE NATIONAL
PARK. SCATTERED THUNDERSTORMS ARE EXPECTED DURING THE AFTERNOON AND
EVENING ACROSS THE KERN COUNTY DESERT AND MOUNTAINS AND THE TULARE
COUNTY MOUNTAINS...WITH ISOLATED MOUNTAIN THUNDERSTORMS FROM FRESNO
COUNTY TO YOSEMITE. OTHERWISE VFR CONDITIONS WILL PREVAIL ELSEWHERE
ACROSS THE CENTRAL CALIFORNIA INTERIOR DURING THE NEXT 24 HOURS.
&&
.AIR QUALITY ISSUES...
ON WEDNESDAY AUGUST 28 2013... UNHEALTHY FOR SENSITIVE GROUPS IN
FRESNO... KERN AND TULARE COUNTIES AND SEQUOIA NATIONAL PARK AND
FOREST.
FURTHER INFORMATION IS AVAILABLE AT VALLEYAIR.ORG
&&
.CERTAINTY...
THE LEVEL OF CERTAINTY FOR DAYS 1 AND 2 IS HIGH.
THE LEVEL OF CERTAINTY FOR DAYS 3 THROUGH 7 IS MEDIUM.
THIS INFORMATION IS PROVIDED AS PART OF A TRIAL PROJECT CONDUCTED
BY THE NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD.
CERTAINTY LEVELS INCLUDE LOW...MEDIUM...AND HIGH. PLEASE VISIT
WWW.WEATHER.GOV/HNX/CERTAINTY.PHP /ALL LOWER CASE/ FOR ADDITIONAL
INFORMATION AND/OR TO PROVIDE FEEDBACK.
&&
.CLIMATE...
RECORDS
SITE DATE HI_MAX:YEAR LO_MAX:YEAR HI_MIN:YEAR LO_MIN:YEAR
KFAT 08-27 109:1924 80:1895 78:1913 51:1895
KFAT 08-28 108:1924 78:1953 77:1894 52:1907
KFAT 08-29 109:1915 79:2010 76:1915 52:1895
KBFL 08-27 111:1931 84:1991 77:1988 45:1903
KBFL 08-28 109:1944 82:1953 78:1972 48:1903
KBFL 08-29 109:1915 79:1953 78:1931 45:1903
&&
.HNX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
PUBLIC...INIGUEZ
AVN/FW...BSO
PREV DISCUSSION...DUDLEY
SYNOPSIS...WP
WEATHER.GOV/HANFORD
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
945 PM PDT SUN AUG 25 2013
.SYNOPSIS...
TROPICAL MOISTURE WILL SPREAD NORTH AND WESTWARD THROUGH MONDAY
EVENING. THIS WILL BRING PERIODS OF HEAVY RAIN SHOWERS AND
THUNDERSTORMS...PARTICULARLY OVER THE MOUNTAINS AND DESERTS. HOWEVER
THERE WILL ALSO BE A CHANCE OF THUNDERSTORMS WITH SIGNIFICANT
RAINFALL WEST OF THE MOUNTAINS. A FLASH FLOOD WATCH IS IN EFFECT FOR
MOST AREAS UNTIL MIDNIGHT MONDAY NIGHT. SHOWERS SHOULD DECREASE
TUESDAY...BUT THE THREAT OF AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS WILL CONTINUE THROUGH THIS WEEK.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
HEAVY RAINFALL/THUNDERSTORMS THIS AFTERNOON AND EVENING...MORE OR
LESS EAST OF A LINE FROM BIG BEAR TO MOUNT SAN JACINTO TO LAKE
HENSHAW THEN SOUTH TO TECATE. RAINFALL AMOUNTS WERE OVER 2 INCHES
AT MANY MOUNTAIN/DESERT LOCATIONS WITH CLOSE TO 4 INCHES BEING
REPORTED BETWEEN COYOTE CREEK AND TORO PEAK. MANY ROADWAYS
FLOODED/WASHED OUT AND REPORTS OF MOTORISTS TRAPPED IN VEHICLES. SEE
LOCAL STORM REPORT SUMMARY ISSUED AT 841 PM PDT...LSRSGX.
SATELLITE IMAGERY...THE HOURLY HRRR MODEL HAS BEEN CONSISTENTLY
SHOWING...ALONG WITH BOTH THE 18Z AND 26/00Z RUNS OF THE GFS
MODEL...NEXT SLUG OF MOISTURE/PRECIPITATION MOVING INTO EASTERN SAN
DIEGO COUNTY NOW AND BEING TRANSPORTED NORTHWESTWARD ACROSS
MOUNTAINS DURING THE NEXT 6 HOURS...REACHING COASTLINE AND MOVING
OUT TO SEA BETWEEN 0200-0500. THE 26/00Z NAM RUN KEEPS THE MOISTURE
EAST OF THE MOUNTAINS. WITH GFS MODEL BEING MOST CONSISTENT THIS
PAST WEEK...WILL STAY WITH IT.
THE FORECAST WAS BASED ON THIS SO ONLY HAD TO MAKE MINOR TWEAKS TO
SHOW HIGHER POPS...EXPAND THE FLASH FLOOD WATCH TO START 8 AM OVER
SAN DIEGO COUNTY INLAND VALLEYS AND GO UNTIL MIDNIGHT MONDAY
NIGHT...AS WELL AS EXTEND UNTIL MIDNIGHT MONDAY NIGHT FOR THE OTHER
ZONES.
FOR LATE MONDAY NIGHT THROUGH SATURDAY...
EXCERPTS FROM AFTERNOON DISCUSSION...
THE NAM12 CARRIES AN UPPER CIRCULATION FEATURE NORTH...OFF THE COAST
MON NIGHT/TUE MORNING. THERE IS SOME INSTABILITY ASSOCIATED WITH
THIS AND PWS REMAIN IN EXCESS OF 1.5 INCHES...SO THERE IS A CHANCE
OF SOME NOCTURNAL CONVECTION OVER THE ENTIRE CWA...BUT FORCING LOOKS
LIMITED FOR WIDESPREAD DEVELOPMENT. THE MARINE LAYER SHOULD REMAIN
QUITE SHALLOW AND DISORGANIZED...MAINLY OVER THE COASTAL WATERS.
LITTLE CHANGE IN THE UPPER AIR PATTERN THIS WEEK WITH THE LARGE
SUBTROPICAL HIGH CENTERED OVER THE SOUTHERN PLAINS...AND A LONG WAVE
TROUGH PARKED OFF THE WEST COAST OF CANADA AND PACNW. THIS KEEPS
SUFFICIENT MONSOONAL MOISTURE OVER THE AREA TO FEED AFTERNOON AND
EVENING CONVECTION IN THE MTNS/DESERTS. OTHERWISE...SEASONALLY WARM
WITH A SHALLOW MARINE LAYER SUPPORTING CAMEO APPEARANCES OF
NOCTURNAL FOG/LOW CLOUDS ALONG THE COAST AT TIMES.
&&
.HYDROLOGY...
ISSUED AN UNSCHEDULED QPSSGX.
ADDITIONAL STORM TOTALS REMAINDER MONDAY THROUGH TUESDAY...
MOUNTAINS 2-4 INCHES...
DESERTS...1-2 INCHES...
WEST OF A INTERSTATE 215/HIGHWAY 67/HIGHWAY 125TO COASTAL
FOOTHILLS...0.50 TO 1.75 INCHES...
SANTA ANA MOUNTAINS/FOOTHILLS /REMAINDER OF INLAND EMPIRE/AND WEST
TO INTERSTATE 5...0.25 TO 0.50 INCHES...
COASTAL SECTIONS...0.10 TO 0.25 INCHES.
ABOVE NUMBERS REFLECT AVERAGE AREAL RAINFALL COVERAGE AND INDIVIDUAL
LOCATIONS WILL LIKELY HAVE MUCH HEAVIER AMOUNT UNDER SLOW MOVING OR
REPEAT THUNDERSTORM CELLS. EACH THUNDERSTORM COULD EASILY DUMP
OVER TWO INCHES OF RAIN PER HOUR...AND IF SEVERAL THUNDERSTORMS HIT
THE SAME LOCATION DURING A 6 HOUR PERIOD...YOU CAN DO THE MATH. THIS
IS A MOIST MARITIME TROPICAL AIR MASS SO THINK FLORIDA OR ANY OF THE
GULF COAST STATES AND NOT THE NORMAL MODIFIED CONTINENTAL AIR MASS
THAT WE USUALLY DEAL WITH IN MONSOON EVENTS.
&&
.AVIATION...
260300Z...COAST/VALLEYS...FORECAST CONFIDENCE THIS CYCLE...MODERATE.
AREAS OF LOW CLOUDS AND FOG WILL LIKELY RETURN TO THE COASTAL AREAS
THIS EVENING AND MAY INTERMITTENTLY IMPACT THE COASTAL TAF SITES
AFTER 06Z MON WITH BKN-OVC CIGS AROUND 500 TO 700 FT MSL AND VIS
1-3SM LOCALLY BLO 1SM. LOW CLOUDS AND FOG SHOULD CLEAR BY 261800Z
MON. OTHERWISE...SCT CLOUDS AOA 10000 FT WITH UNRESTRICTED VIS
THROUGH THIS EVENING. ISOLD THUNDERSTORMS AND SHOWERS ARE POSSIBLE
TONIGHT THROUGH MON AS THE MOISTURE FR0M THE REMNANTS OF IVO SURGE A
BIT FURTHER WEST.
MTNS/DESERTS...SCT TSTMS WITH SCT-BKN CLOUDS LAYERED FROM 8000 FT TO
35000 FT. VSBY MAY BE LIMITED FOR SHORT PERIODS NEAR THUNDERSTORMS
DUE TO HEAVY RAIN OR BLOWING DUST FROM GUSTY WINDS.
&&
.MARINE...
ISOLATED SHOWERS AND THUNDERSTORMS ARE POSSIBLE OVER THE COASTAL
WATERS TONIGHT AND MONDAY. THESE STORMS COULD PRODUCE LOWER
VISIBILITY DUE TO HEAVY RAIN...CLOUD TO WATER LIGHTNING...SMALL HAIL
AND LOCALLY GUSTY WINDS WITH ROUGH SEAS.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR THE APPLE AND
LUCERNE VALLEYS...COACHELLA VALLEY...RIVERSIDE COUNTY
MOUNTAINS...SAN BERNARDINO COUNTY MOUNTAINS...SAN DIEGO
COUNTY DESERTS...SAN DIEGO COUNTY MOUNTAINS.
FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR THE SAN BERNARDINO
AND RIVERSIDE COUNTY VALLEYS-THE INLAND EMPIRE...SANTA ANA
MOUNTAINS AND FOOTHILLS.
FLASH FLOOD WATCH FROM 8 AM PDT MONDAY THROUGH MONDAY EVENING
FOR THE SAN DIEGO COUNTY VALLEYS.
PZ...NONE.
&&
$$
PUBLIC/FIRE WEATHER...BALFOUR
AVIATION/MARINE...JJT/PIERCE
SHORT TERM WARNINGS...MAXWELL/JJT
GRAPHICS...BA
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
831 PM MDT TUE AUG 27 2013
.UPDATE...
ISSUED AT 820 PM MDT TUE AUG 27 2013
HAVE ALLOWED THE FLOOD WATCH FOR EASTERN UTAH TO EXPIRE AND WILL
BE ADJUSTING POPS TO FIT CURRENT TRENDS. BULK OF THE STRONG
CONVECTION HAS DIMINISHED...BUT STILL EXPECT A FEW SHOWERS TO LIFT
NORTH AND EAST ACROSS OUR EASTERN ZONES THROUGH 0200 WEDNESDAY
MORNING...WHICH IS HANDLED FAIRLY WELL WITH THE LAST HRRR RUNS.
OTHERWISE...NO MAJOR CHANGES ATTM.
&&
.SHORT TERM...(TONIGHT THROUGH WEDNESDAY NIGHT)
ISSUED AT 341 PM MDT TUE AUG 27 2013
DEEP MOISTURE CONTINUED TO STREAM NORTHWARD ACROSS THE AREA THIS
AFTERNOON...THOUGH DRYING AT MID-LEVELS HAD DECREASED PWAT VALUES.
SUNSHINE THROUGHOUT THE EARLY PART OF THE DAY BROUGHT SCATTERED
SHOWERS AND THUNDERSTORMS...MAINLY OVER THE MOUNTAINS OF SOUTHEAST
UTAH AND SOUTHWEST COLORADO. SOME STORMS HAVE PRODUCED HEAVY RAIN
PROMPTING ISSUANCE OF SEVERAL FLASH FLOOD WARNINGS.
DIURNAL HEATING WILL SUSTAIN SCATTERED ACTIVITY INTO THE EVENING
BUT AM UNABLE TO IDENTIFY AN UPPER LEVEL SUPPORT FOR MOIST
CONVECTION DURING THE OVERNIGHT HOURS.
AS HIGH PRESSURE CONTINUES TO SHUNT THE MONSOONAL MOISTURE TAP
WESTWARD...EXPECT DECREASED COVERAGE AND INTENSITY OF DIURNAL STORMS
WEDNESDAY AFTERNOON AND EVENING. IN ADDITION...DEVELOPING STORMS
WILL BE LESS EFFICIENT RAIN PRODUCERS.
TEMPERATURES WILL CONTINUE TO HOVER NEAR NORMAL TONIGHT AND
WEDNESDAY NIGHT WITH HIGHS ON WEDNESDAY NEAR NORMAL.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 341 PM MDT TUE AUG 27 2013
THURSDAY THROUGH FRIDAY...THE UPPER RIDGE OF HIGH PRESSURE WILL
BECOME RECENTERED OVER NORTHERN NM/SOUTHEASTERN CO ON THURSDAY WITH
MUCH OF THE MONSOONAL MOISTURE PLUME BRIEFLY CUTOFF. ADEQUATE
MOISTURE WILL REMAIN UNDER THE HIGH FOR SCATTERED DAILY
THUNDERSTORMS ACROSS THE CWA BOTH DAYS AS PW VALUES WILL RANGE FROM
0.6-0.9 INCHES. IN THE WEAKLY SHEARED ENVIRONMENT...STORMS ARE
EXPECTED TO BE DIURNALLY DRIVEN REMAINING PRIMARILY OVER THE TERRAIN
IN THE WEAK FLOW WITH ONLY A FEW DRIFTING INTO THE LOWER VALLEYS...
ALTHOUGH A GRADUAL INCREASE IN MOISTURE FRIDAY AFTERNOON MAY LEAD TO
A SUBTLE UPTICK IN ACTIVITY.
LABOR DAY WEEKEND THROUGH TUESDAY...MODELS HAVE BEEN FAIRLY
CONSISTENT WITH DEEP MONSOONAL MOISTURE ONCE AGAIN EXPECTED TO
SPREAD NORTHWARD ACROSS THE REGION BEGINNING SATURDAY CONTINUING
THROUGH EARLY NEXT WEEK. 12Z MODEL RUNS DID BACK AWAY SOMEWHAT FROM
EARLIER ROBUST PW FORECASTS OF 1.3-1.4 INCHES...BUT ARE STILL
FORECASTING RESPECTABLE VALUES AROUND 1.0-1.2 INCHES...SO CERTAINLY
VERY MOIST AIR FOR THIS REGION REGARDLESS. WEAK FORCING WILL ALSO BE
AVAILABLE FROM THE REMAINS OF AN INVERTED TROUGH SHEARING APART...ALL
THIS POINTS TO MORE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY.
LOCALLY HEAVY RAIN AND FLASH FLOODING MAY BECOME A CONCERN ONCE
AGAIN. WITH ALL THIS IN MIND CONTINUED TO BUMP UP THE BLENDED POP
GUIDANCE DURING THIS EXTENDED PERIOD. DAYTIME TEMPERATURES WILL
REMAIN NEAR SEASONAL VALUES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY EVENING)
ISSUED AT 820 PM MDT TUE AUG 27 2013
CONVECTION WILL CONTINUE TO DIMINISH ACROSS EASTERN UTAH AND
WESTERN COLORADO...COMING TO AN END AROUND 08Z WEDNESDAY MORNING.
EXPECT ANOTHER ROUND OF THUNDERSTORMS TO DEVELOP AFTER 18Z
WEDNESDAY AND LINGER THROUGH 03Z THURSDAY. HEAVY RAIN AND SMALL
HAIL WILL ACCOMPANY THE STRONGER STORMS...ALONG WITH AN INCREASING
POTENTIAL FOR GUSTY OUTFLOW WINDS TO 40KTS OR BETTER AS THE
ATMOSPHERE UNDERGOES SUBTLE DRYING. BRIEF MVFR CIGS AND VSBYS MAY
BE ENCOUNTERED NEAR SHOWERS AND THUNDERSTORMS...OTHERWISE VFR
CONDITIONS WILL PREVAIL.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
UPDATE...JDC
SHORT TERM...NL
LONG TERM...TB
AVIATION...JDC
AREA FORECAST DISCUSSION
NWS MIAMI FL
827 PM EDT TUE AUG 27 2013
.UPDATE...
SHOWERS AND A FEW EMBEDDED THUNDERSTORMS ASSOCIATED WITH A
PERSISTENT UPPER LEVEL LOW ACROSS SOUTH FLORIDA CONTINUE MAINLY
ACROSS THE ATLANTIC AND GULF WATERS. LATEST HRRR DEPICTS DEEPER
MOISTURE SWINGING WEST ACROSS THE ATLANTIC WATERS AND INTO THE
EAST COAST OVERNIGHT WITH A WEAK SURFACE TROUGH IN PLACE. WILL
KEEP CHANCE POP OVERNIGHT FOR THE EAST COAST METRO AREAS.
&&
.AVIATION...
WEATHER OVER SOUTH FLORIDA WILL CONTINUE TO BE DOMINATED BY MAINLY
MID-LEVEL LOW PRESSURE CENTERED OVER FLORIDA STRAITS...WHICH WILL
DRIFT WESTWARD FOR NEXT 24-36 HOURS. THIS MEANS MOIST EASTERLY FLOW
WILL PREVAIL...AT SPEEDS OF 5 TO 10 KTS AT THE SURFACE. SCATTERED
SHOWERS AND A FEW THUNDERSTORMS ARE EXPECTED ACROSS EASTERN
TERMINALS EVEN DURING THE OVERNIGHT...THUS VCSH TAFS STARTING AT
2-4Z AND CONTINUING THROUGH TAF PERIOD. EXCEPTION IS NAPLES WHERE
POP IS AROUND 30 PERCENT FOR TONIGHT AND WEDNESDAY. TEMPO THUNDER
GROUP PLACED IN PBI TAF DUE TO CLUSTER OF STORMS APPROACHING FROM
ATLANTIC AT 0Z.
&&
.PREV DISCUSSION... /ISSUED 254 PM EDT TUE AUG 27 2013/
DISCUSSION...
THE MODEL TRENDS THE LAST COUPLE OF DAYS HAVE EMPHASIZED A CUT-
OFF MID TO UPPER LEVEL LOW FORECAST TO LINGER ACROSS THE REGION
THROUGH THE EARLY PART OF THE WEEK AND THEN A DRYING TREND DURING
THAT PERIOD. HOWEVER...THE LATEST GUIDANCE CONTINUES TO SUGGEST
THAT THE MID TO UPPER LEVEL LOW WILL LIKELY CONTINUE THROUGH THE
REMAINDER OF THE WEEK AND POSSIBLY INTO THE WEEKEND. IN ADDITION
THE LATEST GUIDANCE SUGGESTS THAT THE DRYING TREND WILL BE DELAYED.
FOR TONIGHT...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE
FORECAST TO CONTINUE MAINLY ACROSS THE SOUTHERN AND EASTERN
PORTIONS OF THE PENINSULA WITH THE MORE NUMEROUS ACTIVITY EXPECTED
ACROSS THE SOUTHERN PORTION OF THE PENINSULA AND ADJACENT GULF
AND ATLANTIC WATERS.
THE LOW LEVEL FLOW AT THE 850 HPA LEVEL IS FORECAST TO BECOME MORE
SOUTHERLY TONIGHT INTO WEDNESDAY AND WILL MAINTAIN DEEPER LAYERED
MOISTURE ACROSS THE REGION. FORECAST SOUNDINGS INDICATE FORECAST
PWAT AROUND 1.9 INCHES ON WEDNESDAY. THE LINGERING UPPER LEVEL LOW
AND COOLER MID LEVELS WILL CONTINUE TO ALLOW FOR A CHANCE OF
AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS ON WEDNESDAY. ON
THURSDAY AND FRIDAY THE UPPER LEVEL LOW IS FORECAST TO LINGER
ACROSS THE REGION AND WILL ALSO ADD TO THE UNCERTAINTY OF THE
FORECAST. ALTHOUGH MAINLY ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS ARE FORECAST THURSDAY AND FRIDAY...THERE WILL BE
SUFFICIENT LINGERING MOISTURE THAT MORE MORE WIDE SPREAD COVERAGE
IS POSSIBLE DEPENDING ON THE POSITION OF THE UPPER LOW. WILL HAVE TO
WAIT AND SEE HOW THE MODELS HANDLE THE EVOLUTION OF THE UPPER LOW
FOR THE LATER PART OF THE WEEK INTO THE WEEKEND.
MARINE...
A WEAK PRESSURE GRADIENT AND LIGHTER AND AT TIMES VARIABLE WINDS
TO 10 KNOTS OR LESS ARE FORECAST ACROSS THE REGIONAL WATERS
THROUGH MOST OF THE FORECAST PERIOD WITH MOSTLY TRANQUIL SEAS
FORECAST THROUGH THE FORECAST PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 78 91 77 91 / 30 30 20 20
FORT LAUDERDALE 77 88 78 90 / 50 30 20 20
MIAMI 75 90 77 91 / 50 30 20 20
NAPLES 75 90 76 89 / 30 30 20 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...10/CD
AVIATION/RADAR...23/SK
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
432 PM EDT MON AUG 26 2013
.SHORT TERM (TONIGHT THROUGH WEDNESDAY)...AS DISCUSSED THIS
MORNING...AN AREA OF Q-VECTOR DIVERGENCE AND SUBSIDENCE HAS NOT
ELIMINATED AFTN CONVECTION...BUT THUS FAR SEEMS TO BE LIMITING
UPDRAFT STRENGTH AND OVERALL STRENGTH/COVERAGE OF THE STORMS. THAT
SAID...THERE ARE SCT SHRA AND TSTMS MVG WSW AT NEAR 20 KTS ACROSS
CEN FL AND GIVEN THIS MOTION IT HAS NOT TAKEN MUCH TO PROVIDE SOME
GUSTS TO 35 KTS IN A FEW. IN ADDITION...A WEST COAST SEA BREEZE HAS
FORMED AND MOVED SLIGHTLY INLAND AND THIS MAY HELP INVIGORATED
STORMS AS THEY MOVE ACROSS THE BOUNDARY AND INTO THE WATERS. WILL
CONTINUE TO SHOW SCT POPS FOR REMAINDER OF THE AFTN AND EVENING
FOCUSING ALONG THE COAST AND THEN OFFSHORE (SRN 2/3RDS) FOR BEST
CHCS. COULD SEE SOME GUSTY WINDS WITH THESE FOR MARINE AREAS...ESP
FROM TAMPA BAY SOUTH WHERE HRRR SHOWS THE BEST FLARE UP IN
CONVECTION LATE.
AREA OF WEAK LARGE SCALE SUBSIDENCE SEEN IN Q-VECTORS TODAY MOVES
SOUTH OUT OF THE REGION FOR TUE LEAVING A MORE NEUTRAL REGIME IN
PLACE. OVERALL MOISTURE/PWS ARE FORECAST TO DECREASE
SLIGHTLY AS MODEST DRYING CONTINUES FROM THE ENE AROUND SFC HIGH
CENTERED TO THE NORTH...BUT WHAT MOISTURE IS PRESENT REMAINS ALL PACKED
IN LOWEST LAYERS. GIVEN THIS...THINK MOS POPS ARE ON LOW SIDE AND
LEANED A BIT MORE TOWARD CLIMO WIND REGIME POPS WHICH SUGGEST
30-40% CHCS FAVORING COASTAL COS ON TUE. IN FACT W/O
SUBSIDENCE...MAY SEE SOME BETTER UPDRAFTS THAN WE HAVE TODAY. BY
WED MOISTURE CONTENT IS AT LOWEST POINT AND POPS ARE CONFINED TO
20-30 PERCENT FOR ALL BE FMY AREA WHERE POPS ARE CLOSER TO 40%. SO
OVERALL WILL SEE NOTICEABLY LOWER COVERAGE OF STORMS THAN LAST WEEK
ALTHOUGH NOT COMPLETELY DRY.
&&
.LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY)...
LONG TERM PERIOD BEGINS WITH A SURFACE RIDGE OF HIGH PRESSURE
SITTING ACROSS NORTH FLORIDA AND THE GULF STATES...A 500 MB HIGH
PRESSURE AREA DOMINATES THE CENTRAL UNITED STATES. A STALLED FRONT
EAST AND SOUTH OF FLORIDA ALIGNS WITH AN AMPLIFYING 500 MB TROUGH
OVER THE EASTERN UNITED STATES HEADING INTO NEXT WEEKEND.
INTERESTINGLY...THE 00Z GFS HAS THE TROUGH BRIEFLY FORMING A
CUTOFF LOW AS BOTH THE SURFACE RIDGE AND THE 500 MB DOME OF HIGH
PRESSURE BEGIN TO ERODE. THIS COULD OPEN THE DOOR TO HIGHER RAIN
CHANCES LATE WEEK INTO THE WEEKEND.
HIGH PRESSURE BEGINS TO BUILD BACK IN BY THE END OF THE LONG
TERM FORECAST PERIOD ON MONDAY...AS THE 500 MB TROUGH BACKS NORTH.
EXPECT TEMPERATURES TO STAY NEAR CLIMATOLOGICAL NORMALS IN THE
EXTENDED PERIOD...THOUGH POPS COULD BE AFFECTED BY THE TROUGH
AMPLIFYING OVER THE EASTERN US. SEA BREEZE CONVECTION WILL BE A
LARGE DRIVER OF POPS...THOUGH THE SYNOPTIC INFLUENCES COULD RAISE
RAIN CHANCES ABOVE NORMAL.
&&
.AVIATION...
PREVAILING VFR WITH VCNTY TSRA DURING A 20Z-03Z WINDOW ALTHOUGH
PGD/FMY/RSW COULD SEE A TSRA AT THE FIELD. EASTERLY WINDS DIMINISH
LATER TONIGHT AND BACK TO NE WITH SOME LOW STRATUS POSSIBLE BUT WILL
KEEP TAFS AT SCT010-020.
&&
.FIRE WEATHER...NO CONCERNS.
&&
,MARINE...MAIN CONCERN IS WITH GUSTY WINDS ASSOC W/ OFFSHORE MOVG
TSTMS NEXT FEW DAYS. MAY SEE SUSTAINED WINDS NEAR SCEC LEVELS WITH
ERLY SURGE TONIGHT...BUT FOR NOW KEPT SPEEDS AROUND 15 KTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 74 89 76 91 / 30 40 20 30
FMY 74 92 74 92 / 20 40 20 40
GIF 72 91 72 92 / 10 30 10 30
SRQ 74 90 73 89 / 30 40 20 30
BKV 69 91 69 92 / 10 40 20 20
SPG 77 89 77 90 / 30 40 20 30
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SHORT TERM/MARINE/FIRE WEATHER...88/GITTINGER
LONG TERM/AVIATION...09/RUDE
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1018 PM CDT TUE AUG 27 2013
.DISCUSSION...
915 PM CDT
SOME SMALL CHANGES MADE TO THE GOING FORECAST THIS EVE. HAVE
CONFINED THE POPS IN IL MORE TO JUST FAR NORTHEAST IL MOVING THEM
EAST OF ROCKFORD. HAVE ALSO BUMPED UP CLOUD COVER WEDNESDAY
MORNING IN NORTHEAST IL AND NORTHWEST IN AND SLOWED THE MORNING
TEMPERATURE CLIMB...NAMELY NEAR THE LAKE MI SHORE INCLUDING
DOWNTOWN CHICAGO.
CONTINUE TO MONITOR CONVECTIVE BEHAVIOR OVER EASTERN AND CENTRAL
WISCONSIN AS WE MOVE THROUGH THE LATE EVE INTO THE OVERNIGHT.
STORMS HAVE BEEN FIRING SINCE MID-AFTERNOON ALONG THE ELONGATED
SURFACE BOUNDARY AND WITHIN THE PERIPHERY OF THE HEAT DOME/UPPER
RIDGE AND PWAT MAX /AROUND TWO AND A QUARTER ON 00Z GRB SOUNDING/.
THESE HAVE SLOWLY EVOLVED SOUTHEASTWARD FEEDING ON INSTABILITY AND
THE EDGE OF THE CAP AND MOVING WITHIN THE MEAN NW MID-LEVEL FLOW.
STORM MODE ACROSS EASTERN WI HAS BEEN MAINLY DISCRETE...INCLUDING
A COUPLE SEVERE SUPERCELLS. OUTFLOWS HAVE GENERALLY MERGED THOUGH
PER THE GRB RADAR AND OBSERVATIONS...AND THE MOST PRONOUNCED AND
FURTHEST SOUTH ONE IS APPROACHING AT AROUND 20 KT. WHILE THERE IS
AMPLE INSTABILITY PRESENT...IT APPEARS A LOW-LEVEL INVERSION IS
DEVELOPING BASED ON AMDAR SOUNDINGS AND THE EXPANDING MKX RADAR
BLOOM. SO POTENTIAL FOR NEW CONVECTION ALONG THIS OUTFLOW MAY BE
WANING...AS MAY BE THE FORWARD PROPAGATION SPEED UNLESS SOME NEW
CONVECTION DEVELOPS. STILL SOME POTENTIAL FOR THE ADJACENT LAKE MI
AREAS TO BE CLIPPED GIVEN RAP FORECAST CORFIDI VECTOR STORM
MOTIONS...AND ESPECIALLY IF STORMS AND ASSOCIATED OUTFLOWS PICK UP
PACE SOUTHWARD OVER THE LAKE. THERE WOULD BE SOME WIND POTENTIAL
WITH THESE...BUT OVERALL RADAR TRENDS IN THE PAST HALF HOUR
UPSTREAM POINT TOWARD ANY STRONG STORM POTENTIAL DROPPING QUICKLY.
GIVEN THE PHASED OUTFLOWS IT DOES LOOK LIKE THE SURFACE WIND
SHIFT TO N/NE MAY OCCUR EARLIER THAN ORIGINALLY THOUGHT IN
NORTHEAST IL...WHICH MEANS ADVECTION OF THE MARINE LAYER OVER
LAND TO OCCUR MORE DURING NIGHT. THE 00Z NAM IS MORE PESSIMISTIC
THAN ITS PREDECEASING RUN WITH A MOISTENING LOW-LEVEL INVERSION AND
CLOUDS...AND THAT AGREES WITH THE RAP. THIS MAKES SENSE NOT
NECESSARILY GIVEN CLIMATOLOGY FOR LATE AUG BUT CLIMATOLOGY GIVEN
THE SYNOPTIC SITUATION AND UPSTREAM OBS OF CIGS BEHIND THE FRONT.
WHILE THERE IS POTENTIAL FOR FOG TOO FROM THE MARINE
LAYER...FORECAST SOUNDINGS WOULD INDICATE MORE FAVORED STRATUS AND
THAT HAS BEEN THE OBSERVATIONAL TREND THUS FAR. SO HAVE SLOWED
THE MORNING TEMPERATURE CLIMB OVER CHICAGO AND FAR NW IN BUT NOT
ADJUSTED HIGHS AT THIS POINT.
MTF
//PREV DISCUSSION...
252 PM CDT
LATE SEASON HEAT HAS DEVELOPED THIS AFTERNOON ACROSS NORTHERN
IL/NORTHWEST IN WITH TEMPS PUSHING INTO THE MID 90S...WITH A FEW
AREAS TOUCHING THE UPR 90S. THIS COUPLED WITH DEW POINTS HOLDING
AROUND 70 DEGREES HAS RESULTED IN HEAT INDEX VALUES BETWEEN 98-105
IN SEVERAL LOCATIONS. THE HEAT ADVISORY HAS REMAINED IN PLACE
ACROSS LEE/OGLE/DEKALB/BOONE/WINNEBAGO COUNTIES.
THE MAIN CHALLENGE FOR THIS EVENING THROUGH THE OVERNIGHT WILL BE ON
POSSIBLE CONVECTION WITH A FEW STRONG STORMS DEVELOPING ALONG A
BOUNDARY...WHICH IS PROGGED TO BE SLIDING SOUTHEAST ACROSS WISCONSIN
INTO NORTHEAST IL/NORTHWEST IN. THE CHANNEL OF BETTER ATMOSPHERIC
MOISTURE WAS ORIENTED FROM THE HIGH PLAINS STRETCHING EAST THROUGH
THE UPPER MIDWEST THEN BENDING SOUTHEAST THROUGH THE GREAT LAKES
REGION THIS AFTERNOON. THIS APPEARS TO FIT WELL ALONG THE PROGGED
586-590 HEIGHT CONTOUR...WHICH APPEARS TO REMAIN NEARLY STATIONARY
THROUGH THE NEXT 24 HOURS. THIS AFTERNOON THE BOUNDARY WAS
POSITIONED ACROSS THE UPPER MIDWEST THROUGH THE UPPER PENINSULA OF
MICHIGAN...WHICH IS EXPECTED TO BE THE FOCAL POINT FOR CONVECTIVE
GENERATION LATER THIS AFTERNOON. CURRENT TIMING OF ARRIVAL INTO
NORTHERN IL CONTINUES TO BE JUST AFT 00Z...WITH THE PEAK BETWEEN
03-06Z. WITH THE VERY WARM SFC CONDITIONS THIS AFTN...POTENTIAL
ENERGY WILL LIKELY REMAIN ELEVATED UPON ARRIVAL OF
CLOUDS/CONVECTION...WHICH COULD FURTHER ENHANCE THUNDERSTORMS TO
POSSIBLY REACHING SEVERE LIMITS.
THE LOCATION OF GREATEST CONCERN WILL LIKELY BE ALONG AND NORTHEAST
OF A ROCKFORD TO KANKAKEE LINE...WITH THE MAIN HAZARDS FROM
THUNDERSTORMS BEING BRIEF HEAVY DOWNPOURS/WIND GUSTS TO 60MPH/HAIL
UP TO 1".
AS THE BOUNDARY SLIDES SOUTH ACROSS THE CWFA AFTER MIDNIGHT...WINDS
WILL TURN NORTH/NORTHEAST. LLVL MOISTURE APPEARS TO LINGER THRU
DAYBREAK WED. OVERNIGHT LOWS WILL REMAIN MILD ONE MORE NIGHT IN THE
LOW 70S...TO MID 70S CLOSER TO DOWNTOWN CHICAGO.
WEDNESDAY...
MID-LVL RIDGE CENTER WILL DRIFT SOUTHWEST...ALLOWING HEIGHTS TO
WEAKEN MARGINALLY OVER THE WESTERN GREAT LAKES REGION. GUIDANCE
CONTINUES TO PROG A WEAK WAVE SLIDING ACROSS THE NORTHERN CWFA WED
MORNING...WHICH ALONG WITH THE LINGERING LLVL MOISTURE COULD
TRANSLATE INTO POSSIBLE SHRA/TSRA WED MORNING FOR THE
CENTRAL/SOUTHERN CWFA. AT THIS TIME HAVE MAINTAINED A DRY FORECAST
FOR WED AS ANTI-CYCLONIC FLOW SHOULD SLOWLY SLIDE SOUTH ACROSS THE
LAKES AND STEADILY DRY THE SFC. NORTHEAST LLVL FLOW WILL CONTINUE TO
USHER IN DRIER AIR...WITH SLIGHTLY COOLER TEMPS ALONG THE LAKESHORE
COMMUNITIES. TEMPS FOR FAR NORTHEAST IL/NORTHWEST IN WILL HOVER IN
THE LOW/MID 80S...MEANWHILE FURTHER INLAND TEMPS WILL WARM INTO THE
UPR 80S TO POSSIBLY LOWER 90S ALONG AND SOUTH OF A LASALLE TO
KANKAKEE LINE.
CONFIDENCE...HIGH.
THURSDAY THROUGH LABOR DAY...
CONSIDERABLE CHANGES HAVE TAKEN PLACE IN THE FINAL PERIODS OF THE
EXTENDED...HOWEVER MODEL SPREAD DOES APPEAR TO HAVE DIMINISHED
MARGINALLY WITH RESPECT TO HIGH TEMPS FOR THE HOLIDAY WEEKEND.
ENSEMBLES CONTINUE TO DEMONSTRATE NOISE WITH A WIDE RANGE OF
SOLUTIONS BEYOND FRI. GUIDANCE DOES CONTINUE TO SHOW MID-LVL RIDGE
INFLUENCING THE WEATHER FOR THE WESTERN GREAT LAKES
THUR/FRI...HOWEVER WITH THE CWFA REMAINING ALONG THE NORTHEAST
PERIPHERY OF THE RIDGE...THE PROBABILITY OF ANY WAVES GENERATING
CLOUDS/CONVECTION IS INCREASED FOR THE AREA. CURRENT THINKING IS
THAT SFC RIDGE FROM WED WILL REMAIN IN PLACE THRU THUR THEN BEGIN TO
DRIFT SOUTHEAST THUR NIGHT. THIS WILL BRING THE NEXT CHC FOR
SHRA/TSRA TO THE CWFA THUR NIGHT INTO FRI...LINGERING THRU SAT
BEFORE BEGINNING TO DRY BACK OUT FOR SUN AND LABOR DAY.
ECMWF/GFS HAVE CONTINUED TO PROG A TROUGH DEVELOPING OVER THE
CANADIAN ROCKIES FRI AND PUSHING OVER THE GREAT LAKES REGION SUN.
WITH THE NOW EXPECTED TROUGHING EXPECTED ACROSS THE REGION FOR THE
SECOND HALF OF THE WEEKEND...TEMPS WILL LIKELY SWING IN THE COOLER
DIRECTION WITH HIGHS IN THE UPR 70S TO POSSIBLY MID 80S FOR LABOR
DAY.
CONFIDENCE...MEDIUM.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* LIMITED CHANCE FOR SHRA/TSRA THROUGH EARLY OVERNIGHT.
* FROPA LATE TONIGHT WITH WINDS TURNING TO THE NORTH-
NORTHWEST...AND THEN TO NORTHEAST WEDNESDAY AM. ITS POSSIBLE
SHIFT TO NORTHEAST COULD OCCUR A BIT EARLIER THAN INDICATED IN
TAF.
* POTENTIAL FOR MVFR/IFR CIGS FROM EARLY WEDS AM TO MID WEDS AM.
RC
//DISCUSSION...UPDATED 00Z...
WITH A WARM WELL MIXED BOUNDARY LAYER...WIND GUSTS OUT OF THE
SOUTHWEST FROM 220-250 DEGREES WILL ONLY SLOWLY DIMINISH THROUGH
THE MID-LATE EVENING. NEXT CONCERN IS POTENTIAL FOR CONVECTION
LATE THIS EVENING AHEAD OF A COLD FRONT. STEERING FLOW ALOFT MAY
TRY TO BRING THE NORTHEAST WISCONSIN TSRA SOUTH-SOUTHEAST TOWARD
AREA BUT IT APPEARS BEST POTENTIAL IS PRIMARILY EAST AND GYY WOULD
HAVE BETTER CHANCE THAN IL AIRPORTS. THUS HAVE PULLED VCSH FROM
REMAINING SITES BUT WILL CONTINUE TO MONITOR. IF CONVECTION WERE
TO APPROACH...ROUGH TIMING WOULD BE AROUND 03-07Z.
ONCE COLD FRONT PUSHES THROUGH TERMINALS LATE TONIGHT...WINDS WILL
TURN TO NORTHWEST AND THEN NORTH A FEW HOURS LATER. CONCERNED FOR
LOW CIGS ESPECIALLY AT THE EASTERN SITES NEAR LAKE MICHIGAN.
THOUGH THERE ARE CURRENTLY SOME SITES WITH LOW MVFR AND IFR CIGS
BEHIND THE FRONT IN NORTHERN MI AND WI...THESE ARE NOT ALL THAT
WIDESPREAD...THUS DID NOT INDICATE LOW CIGS IN TAF YET. IF THEY DO
MATERIALIZE...MORNING OPERATIONS COULD BE AFFECTED UNTIL AS LATE
AS ~14-15Z. SOUNDINGS SUGGEST THAT ANY LOW MVFR OR LOWER CIGS WILL
THEN LIFT TO HIGH MVFR BY LATE MORNING AND SCATTER DURING THE
AFTERNOON. WINDS WILL SHIFT FROM NORTH TO NORTHEAST AT OR SLIGHTLY
ABOVE 10 KT WITH SPORADIC HIGHER GUSTS POSSIBLE UNTIL SOME EASING
LATE WEDNESDAY AFTERNOON. TIMING OF THIS WIND SHIFT IS A BIT
UNCERTAIN AND MAY NEED SOME REFINING.
RC
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* MEDIUM-HIGH CONFIDENCE IN NOT SEEING SHRA/TSRA THE REMAINDER OF
THE NIGHT AT THE TERMINALS.
* HIGH CONFIDENCE IN WINDS SHIFTING FROM SOUTHWEST LATE THIS
EVENING TO NORTH-NORTHWEST LATE TONIGHT/EARLY WEDS AND THEN
NORTHEAST WEDS AM. MEDIUM CONFIDENCE IN TIMING THESE SHIFTS.
* LOW-MEDIUM CONFIDENCE IN MVFR/IFR CEILINGS EARLY-MID WEDS AM.
RC
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THURSDAY...VFR.
FRIDAY...CHANCE TSRA...MAINLY FRIDAY EVENING.
SATURDAY...CHANCE TSRA.
SUNDAY...SLIGHT CHANCE TSRA.
MONDAY...VFR.
RC
&&
.MARINE...
242 PM CDT
A BROAD TROUGH STRETCHES ACROSS LAKE MICHIGAN THIS AFTERNOON WITH
GENERALLY SOUTHERLY WINDS ACROSS THE LAKE. AS THE TROUGH SAGS
SOUTHEAST OVER THE NEXT 24 HOURS...WINDS WILL TURN NORTHERLY AS HIGH
PRESSURE BUILDS OVER MINNESOTA AND WISCONSIN WITH WINDS PICKING BACK
UP INTO THE 15 TO 20 KT RANGE. WINDS THEN DIMINISH WEDNESDAY NIGHT
AND THURSDAY AS THE HIGH MOVES OVER LAKE MICHIGAN. ANOTHER FRONT
WILL PASS OVER LAKE MICHIGAN ON SUNDAY...WITH THE GRADIENT
TIGHTENING SUNDAY NIGHT AND MONDAY AS HIGH PRESSURE BUILDS OVER
ONTARIO. WINDS MAY INCREASE FOR A PERIOD INTO THE 30 KT RANGE
MONDAY...THEN DIMINISH MONDAY NIGHT INTO TUESDAY AS THE HIGH
BUILDS SOUTH OVER THE GREAT LAKES.
BMD
&&
.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:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
918 PM CDT TUE AUG 27 2013
.DISCUSSION...
915 PM CDT
SOME SMALL CHANGES MADE TO THE GOING FORECAST THIS EVE. HAVE
CONFINED THE POPS IN IL MORE TO JUST FAR NORTHEAST IL MOVING THEM
EAST OF ROCKFORD. HAVE ALSO BUMPED UP CLOUD COVER WEDNESDAY
MORNING IN NORTHEAST IL AND NORTHWEST IN AND SLOWED THE MORNING
TEMPERATURE CLIMB...NAMELY NEAR THE LAKE MI SHORE INCLUDING
DOWNTOWN CHICAGO.
CONTINUE TO MONITOR CONVECTIVE BEHAVIOR OVER EASTERN AND CENTRAL
WISCONSIN AS WE MOVE THROUGH THE LATE EVE INTO THE OVERNIGHT.
STORMS HAVE BEEN FIRING SINCE MID-AFTERNOON ALONG THE ELONGATED
SURFACE BOUNDARY AND WITHIN THE PERIPHERY OF THE HEAT DOME/UPPER
RIDGE AND PWAT MAX /AROUND TWO AND A QUARTER ON 00Z GRB SOUNDING/.
THESE HAVE SLOWLY EVOLVED SOUTHEASTWARD FEEDING ON INSTABILITY AND
THE EDGE OF THE CAP AND MOVING WITHIN THE MEAN NW MID-LEVEL FLOW.
STORM MODE ACROSS EASTERN WI HAS BEEN MAINLY DISCRETE...INCLUDING
A COUPLE SEVERE SUPERCELLS. OUTFLOWS HAVE GENERALLY MERGED THOUGH
PER THE GRB RADAR AND OBSERVATIONS...AND THE MOST PRONOUNCED AND
FURTHEST SOUTH ONE IS APPROACHING AT AROUND 20 KT. WHILE THERE IS
AMPLE INSTABILITY PRESENT...IT APPEARS A LOW-LEVEL INVERSION IS
DEVELOPING BASED ON AMDAR SOUNDINGS AND THE EXPANDING MKX RADAR
BLOOM. SO POTENTIAL FOR NEW CONVECTION ALONG THIS OUTFLOW MAY BE
WANING...AS MAY BE THE FORWARD PROPAGATION SPEED UNLESS SOME NEW
CONVECTION DEVELOPS. STILL SOME POTENTIAL FOR THE ADJACENT LAKE MI
AREAS TO BE CLIPPED GIVEN RAP FORECAST CORFIDI VECTOR STORM
MOTIONS...AND ESPECIALLY IF STORMS AND ASSOCIATED OUTFLOWS PICK UP
PACE SOUTHWARD OVER THE LAKE. THERE WOULD BE SOME WIND POTENTIAL
WITH THESE...BUT OVERALL RADAR TRENDS IN THE PAST HALF HOUR
UPSTREAM POINT TOWARD ANY STRONG STORM POTENTIAL DROPPING QUICKLY.
GIVEN THE PHASED OUTFLOWS IT DOES LOOK LIKE THE SURFACE WIND
SHIFT TO N/NE MAY OCCUR EARLIER THAN ORIGINALLY THOUGHT IN
NORTHEAST IL...WHICH MEANS ADVECTION OF THE MARINE LAYER OVER
LAND TO OCCUR MORE DURING NIGHT. THE 00Z NAM IS MORE PESSIMISTIC
THAN ITS PREDECEASING RUN WITH A MOISTENING LOW-LEVEL INVERSION AND
CLOUDS...AND THAT AGREES WITH THE RAP. THIS MAKES SENSE NOT
NECESSARILY GIVEN CLIMATOLOGY FOR LATE AUG BUT CLIMATOLOGY GIVEN
THE SYNOPTIC SITUATION AND UPSTREAM OBS OF CIGS BEHIND THE FRONT.
WHILE THERE IS POTENTIAL FOR FOG TOO FROM THE MARINE
LAYER...FORECAST SOUNDINGS WOULD INDICATE MORE FAVORED STRATUS AND
THAT HAS BEEN THE OBSERVATIONAL TREND THUS FAR. SO HAVE SLOWED
THE MORNING TEMPERATURE CLIMB OVER CHICAGO AND FAR NW IN BUT NOT
ADJUSTED HIGHS AT THIS POINT.
MTF
&&
.PREV DISCUSSION...
252 PM CDT
LATE SEASON HEAT HAS DEVELOPED THIS AFTERNOON ACROSS NORTHERN
IL/NORTHWEST IN WITH TEMPS PUSHING INTO THE MID 90S...WITH A FEW
AREAS TOUCHING THE UPR 90S. THIS COUPLED WITH DEW POINTS HOLDING
AROUND 70 DEGREES HAS RESULTED IN HEAT INDEX VALUES BETWEEN 98-105
IN SEVERAL LOCATIONS. THE HEAT ADVISORY HAS REMAINED IN PLACE
ACROSS LEE/OGLE/DEKALB/BOONE/WINNEBAGO COUNTIES.
THE MAIN CHALLENGE FOR THIS EVENING THROUGH THE OVERNIGHT WILL BE ON
POSSIBLE CONVECTION WITH A FEW STRONG STORMS DEVELOPING ALONG A
BOUNDARY...WHICH IS PROGGED TO BE SLIDING SOUTHEAST ACROSS WISCONSIN
INTO NORTHEAST IL/NORTHWEST IN. THE CHANNEL OF BETTER ATMOSPHERIC
MOISTURE WAS ORIENTED FROM THE HIGH PLAINS STRETCHING EAST THROUGH
THE UPPER MIDWEST THEN BENDING SOUTHEAST THROUGH THE GREAT LAKES
REGION THIS AFTERNOON. THIS APPEARS TO FIT WELL ALONG THE PROGGED
586-590 HEIGHT CONTOUR...WHICH APPEARS TO REMAIN NEARLY STATIONARY
THROUGH THE NEXT 24 HOURS. THIS AFTERNOON THE BOUNDARY WAS
POSITIONED ACROSS THE UPPER MIDWEST THROUGH THE UPPER PENINSULA OF
MICHIGAN...WHICH IS EXPECTED TO BE THE FOCAL POINT FOR CONVECTIVE
GENERATION LATER THIS AFTERNOON. CURRENT TIMING OF ARRIVAL INTO
NORTHERN IL CONTINUES TO BE JUST AFT 00Z...WITH THE PEAK BETWEEN
03-06Z. WITH THE VERY WARM SFC CONDITIONS THIS AFTN...POTENTIAL
ENERGY WILL LIKELY REMAIN ELEVATED UPON ARRIVAL OF
CLOUDS/CONVECTION...WHICH COULD FURTHER ENHANCE THUNDERSTORMS TO
POSSIBLY REACHING SEVERE LIMITS.
THE LOCATION OF GREATEST CONCERN WILL LIKELY BE ALONG AND NORTHEAST
OF A ROCKFORD TO KANKAKEE LINE...WITH THE MAIN HAZARDS FROM
THUNDERSTORMS BEING BRIEF HEAVY DOWNPOURS/WIND GUSTS TO 60MPH/HAIL
UP TO 1".
AS THE BOUNDARY SLIDES SOUTH ACROSS THE CWFA AFTER MIDNIGHT...WINDS
WILL TURN NORTH/NORTHEAST. LLVL MOISTURE APPEARS TO LINGER THRU
DAYBREAK WED. OVERNIGHT LOWS WILL REMAIN MILD ONE MORE NIGHT IN THE
LOW 70S...TO MID 70S CLOSER TO DOWNTOWN CHICAGO.
WEDNESDAY...
MID-LVL RIDGE CENTER WILL DRIFT SOUTHWEST...ALLOWING HEIGHTS TO
WEAKEN MARGINALLY OVER THE WESTERN GREAT LAKES REGION. GUIDANCE
CONTINUES TO PROG A WEAK WAVE SLIDING ACROSS THE NORTHERN CWFA WED
MORNING...WHICH ALONG WITH THE LINGERING LLVL MOISTURE COULD
TRANSLATE INTO POSSIBLE SHRA/TSRA WED MORNING FOR THE
CENTRAL/SOUTHERN CWFA. AT THIS TIME HAVE MAINTAINED A DRY FORECAST
FOR WED AS ANTI-CYCLONIC FLOW SHOULD SLOWLY SLIDE SOUTH ACROSS THE
LAKES AND STEADILY DRY THE SFC. NORTHEAST LLVL FLOW WILL CONTINUE TO
USHER IN DRIER AIR...WITH SLIGHTLY COOLER TEMPS ALONG THE LAKESHORE
COMMUNITIES. TEMPS FOR FAR NORTHEAST IL/NORTHWEST IN WILL HOVER IN
THE LOW/MID 80S...MEANWHILE FURTHER INLAND TEMPS WILL WARM INTO THE
UPR 80S TO POSSIBLY LOWER 90S ALONG AND SOUTH OF A LASALLE TO
KANKAKEE LINE.
CONFIDENCE...HIGH.
THURSDAY THROUGH LABOR DAY...
CONSIDERABLE CHANGES HAVE TAKEN PLACE IN THE FINAL PERIODS OF THE
EXTENDED...HOWEVER MODEL SPREAD DOES APPEAR TO HAVE DIMINISHED
MARGINALLY WITH RESPECT TO HIGH TEMPS FOR THE HOLIDAY WEEKEND.
ENSEMBLES CONTINUE TO DEMONSTRATE NOISE WITH A WIDE RANGE OF
SOLUTIONS BEYOND FRI. GUIDANCE DOES CONTINUE TO SHOW MID-LVL RIDGE
INFLUENCING THE WEATHER FOR THE WESTERN GREAT LAKES
THUR/FRI...HOWEVER WITH THE CWFA REMAINING ALONG THE NORTHEAST
PERIPHERY OF THE RIDGE...THE PROBABILITY OF ANY WAVES GENERATING
CLOUDS/CONVECTION IS INCREASED FOR THE AREA. CURRENT THINKING IS
THAT SFC RIDGE FROM WED WILL REMAIN IN PLACE THRU THUR THEN BEGIN TO
DRIFT SOUTHEAST THUR NIGHT. THIS WILL BRING THE NEXT CHC FOR
SHRA/TSRA TO THE CWFA THUR NIGHT INTO FRI...LINGERING THRU SAT
BEFORE BEGINNING TO DRY BACK OUT FOR SUN AND LABOR DAY.
ECMWF/GFS HAVE CONTINUED TO PROG A TROUGH DEVELOPING OVER THE
CANADIAN ROCKIES FRI AND PUSHING OVER THE GREAT LAKES REGION SUN.
WITH THE NOW EXPECTED TROUGHING EXPECTED ACROSS THE REGION FOR THE
SECOND HALF OF THE WEEKEND...TEMPS WILL LIKELY SWING IN THE COOLER
DIRECTION WITH HIGHS IN THE UPR 70S TO POSSIBLY MID 80S FOR LABOR
DAY.
CONFIDENCE...MEDIUM.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* SHOWERS/TS POSSIBLE LATE THIS EVENING.
* FROPA LATE TONIGHT WITH WINDS TURNING TO THE NORTHWEST...AND
EVENTUALLY NORTHEAST EARLY WEDNESDAY MORNING.
* MVFR/IFR CEILINGS POSSIBLE EARLY WEDNESDAY MORNING.
RC
//DISCUSSION...UPDATED 00Z...
WITH A WARM WELL MIXED BOUNDARY LAYER...WIND GUSTS OUT OF THE
SOUTHWEST FROM 220-250 DEGREES WILL ONLY SLOWLY DIMINISH THROUGH
THE MID-LATE EVENING. NEXT CONCERN IS POTENTIAL FOR CONVECTION
LATE THIS EVENING AHEAD OF A COLD FRONT. STEERING FLOW ALOFT MAY
TRY TO BRING THE NORTHEAST WISCONSIN TSRA SOUTH-SOUTHEAST TOWARD
AREA BUT IT APPEARS BEST POTENTIAL IS PRIMARILY EAST AND GYY WOULD
HAVE BETTER CHANCE THAN IL AIRPORTS. THUS HAVE PULLED VCSH FROM
REMAINING SITES BUT WILL CONTINUE TO MONITOR. IF CONVECTION WERE
TO APPROACH...ROUGH TIMING WOULD BE AROUND 03-07Z.
ONCE COLD FRONT PUSHES THROUGH TERMINALS LATE TONIGHT...WINDS WILL
TURN TO NORTHWEST AND THEN NORTH A FEW HOURS LATER. CONCERNED FOR
LOW CIGS ESPECIALLY AT THE EASTERN SITES NEAR LAKE MICHIGAN.
THOUGH THERE ARE CURRENTLY SOME SITES WITH LOW MVFR AND IFR CIGS
BEHIND THE FRONT IN NORTHERN MI AND WI...THESE ARE NOT ALL THAT
WIDESPREAD...THUS DID NOT INDICATE LOW CIGS IN TAF YET. IF THEY DO
MATERIALIZE...MORNING OPERATIONS COULD BE AFFECTED UNTIL AS LATE
AS ~14-15Z. SOUNDINGS SUGGEST THAT ANY LOW MVFR OR LOWER CIGS WILL
THEN LIFT TO HIGH MVFR BY LATE MORNING AND SCATTER DURING THE
AFTERNOON. WINDS WILL SHIFT FROM NORTH TO NORTHEAST AT OR SLIGHTLY
ABOVE 10 KT WITH SPORADIC HIGHER GUSTS POSSIBLE UNTIL SOME EASING
LATE WEDNESDAY AFTERNOON. TIMING OF THIS WIND SHIFT IS A BIT
UNCERTAIN AND MAY NEED SOME REFINING.
RC
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* MEDIUM CONFIDENCE IN SHRA/TSRA REMAINING EAST OF THE TERMINALS
LATER THIS EVENING.
* HIGH CONFIDENCE IN WINDS SHIFTING FROM SOUTHWEST THIS EVENING TO
NORTH-NORTHWEST LATE TONIGHT/EARLY WEDS AND THEN NORTHEAST BY
MID WEDS AM. MEDIUM CONFIDENCE IN TIMING THESE SHIFTS.
* LOW-MEDIUM CONFIDENCE IN MVFR/IFR CEILINGS EARLY WEDNESDAY
MORNING.
RC
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THURSDAY...VFR.
FRIDAY...CHANCE TSRA...MAINLY FRIDAY EVENING.
SATURDAY...CHANCE TSRA.
SUNDAY...SLIGHT CHANCE TSRA.
MONDAY...VFR.
RC
&&
.MARINE...
242 PM CDT
A BROAD TROUGH STRETCHES ACROSS LAKE MICHIGAN THIS AFTERNOON WITH
GENERALLY SOUTHERLY WINDS ACROSS THE LAKE. AS THE TROUGH SAGS
SOUTHEAST OVER THE NEXT 24 HOURS...WINDS WILL TURN NORTHERLY AS HIGH
PRESSURE BUILDS OVER MINNESOTA AND WISCONSIN WITH WINDS PICKING BACK
UP INTO THE 15 TO 20 KT RANGE. WINDS THEN DIMINISH WEDNESDAY NIGHT
AND THURSDAY AS THE HIGH MOVES OVER LAKE MICHIGAN. ANOTHER FRONT
WILL PASS OVER LAKE MICHIGAN ON SUNDAY...WITH THE GRADIENT
TIGHTENING SUNDAY NIGHT AND MONDAY AS HIGH PRESSURE BUILDS OVER
ONTARIO. WINDS MAY INCREASE FOR A PERIOD INTO THE 30 KT RANGE
MONDAY...THEN DIMINISH MONDAY NIGHT INTO TUESDAY AS THE HIGH
BUILDS SOUTH OVER THE GREAT LAKES.
BMD
&&
.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:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1043 AM MDT MON AUG 26 2013
.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 243 AM MDT MON AUG 26 2013
LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOW LARGE H5 598DM RIDGE
STILL IN PLACE ACROSS THE CENTRAL CONUS. WHILE THERE IS WEAK
ENERGY ROTATING AROUND THE WEST SIDE OF THE RIDGE THAT CONTINUES TO
INITIATE SHOWER/THUNDERSTORM ACTIVITY OVER THE MOUNTAINS...BEYOND
HIGH CLOUDS MOVING ACROSS THE WESTERN PART OF OUR CWA THESE WEAK
WAVES WILL NOT HAVE ANY INFLUENCE ON OUR WEATHER LOCALLY. WITH
THIS VERY STAGNANT PATTERN IN PLACE FORECAST FOCUS CONTINUES TO
BE ON HOT TEMPERATURES AND MARGINAL FIRE WEATHER CONDITIONS.
TIGHT GRADIENT IS STILL IN PLACE ACROSS OUR CWA ON EASTER EDGE OF
TEE TROUGH...HOWEVER THE MAIN TROUGH AXIS IS BEGINNING OT SHIFT
CLOSER TO THE KS/CO BORDER WHICH SHOULD HELP RELAX THE GRADIENT
ACROSS THE NW HALF OF OUR CWA. AS WOULD BE EXPECTED WITH LESS
GRADIENT IN THE NW PART OF OUR CWA...SHORT RANGE MODELS ARE
BACKING OFF ON WINDS ACROSS THE WEST...WITH GUSTY WINDS MAINLY
ACROSS OUR EASTERN CWA. LOWEST RH VALUES SHOULD BE ACROSS THE WEST
AS HAS BEEN THE CASE THE LAST FEW DAYS...AND ARE ALREADY MARGINAL
FOR RFW. THE CHANCE FOR RH/WIND CROSSOVER IS VERY LOW...SO FIRE
WEATHER HIGHLIGHT WILL NOT BE NECESSARY.
REGARDING TEMPERATURES...NAM/GFS/ECMWF ALL SHOW VERY SIMILAR
AIR MASS IN PLACE THROUGH TUESDAY WHICH MEAN THERE SHOULDNT BE A
LOT OF VARIANCE FROM UPPER 90S/LOW 100S. BETTER MIXING COULD
RESULT IN NEAR RECORD HIGHS AT A FEW LOCATIONS. I DECIDED TO KEEP
ONGOING FORECAST WITHIN A DEGREE OR TWO OF PERSISTENCE WITH LITTLE
EXPECTED TO CHANGE. THROUGH TUESDAY NIGHT. BY WEDNESDAY A
SHORTWAVE TROUGH/MID LEVEL VORTICITY MAX WILL ROTATE FROM THE
SOUTHERN PLAINS AND ACROSS WESTERN KANSAS OUT OF THE SOUTH. WHILE
LARGE SCALE ASCENT AND ELEVATED INSTABILITY ASSOCIATED WITH A
MID LEVEL COLD POOL WILL MOVE OVER THE CWA...THERE IS A
SIGNIFICANTLY DRY AIR MASS IN PLACE. BEYOND AN INCREASE IN CLOUDS I
AM NOT ANTICIPATING ANY PRECIP WITH THIS FEATURE. THIS WILL HELP
REDUCE TEMPS OVER THE CWA BY ABOUT 5-7F FOR MOST LOCATIONS...WHICH
IS A SMALL CONCESSION SINCE THIS IS STILL WELL ABOVE NORMAL.
.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 243 AM MDT MON AUG 26 2013
THE UPPER LEVEL RIDGE WILL PERSIST THROUGH THE EXTENDED PERIOD. THE
WARMEST 850 MB TEMPERATURES WILL BE ON FRIDAY AND SATURDAY RESULTING
IN HIGH TEMPERATURES IN THE UPPER 90S TO NEAR 100 DEGREES BOTH DAYS.
DIFFERENCES IN MEDIUM RANGE MODELS EMERGE OVER THE WEEKEND WITH THE
CHARACTER AND POSITION OF THE UPPER LEVEL RIDGE AND THE EASTWARD
PROGRESSION OF PACIFIC NORTHWEST TROUGH. GFS ENSEMBLE MEAN IS THE
MOST PROGRESSIVE SHIFTING BOTH FEATURES EASTWARD AND PLACING THE
AREA IN SOUTHWESTERLY FLOW ALOFT. IN CONTRAST ECMWF HOLDS THE RIDGE
OVER THE AREA WITH A SLIGHT DEAMPLIFICATION AS A SHORTWAVE TROUGH
MOVES EASTWARD ACROSS THE NORTHERN PLAINS. IN EITHER SCENARIO...A
GENERALLY DRY PATTERN WITH ABOVE NORMAL TEMPERATURES ARE LIKELY TO
PERSIST THROUGH THE WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1039 AM MDT MON AUG 26 2013
VFR CONDITIONS WILL PERSIST AT KGLD AND KMCK FOR THE NEXT 24
HOURS. SUBSIDENCE WILL KEEP A CLEAR SKY ACROSS THE REGION. SOUTH
WINDS WILL BE GUSTY THIS AFTERNOON IN RESPONSE TO A SURFACE TROUGH
IN EASTERN COLORADO. WIND WILL DECREASE SOME TONIGHT BUT WILL
REMAIN OUT OF THE SOUTH.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...BRB
AVIATION...FS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
520 AM MDT MON AUG 26 2013
.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 243 AM MDT MON AUG 26 2013
LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOW LARGE H5 598DM RIDGE
STILL IN PLACE ACROSS THE CENTRAL CONUS. WHILE THERE IS WEAK
ENERGY ROTATING AROUND THE WEST SIDE OF THE RIDGE THAT CONTINUES TO
INITIATE SHOWER/THUNDERSTORM ACTIVITY OVER THE MOUNTAINS...BEYOND
HIGH CLOUDS MOVING ACROSS THE WESTERN PART OF OUR CWA THESE WEAK
WAVES WILL NOT HAVE ANY INFLUENCE ON OUR WEATHER LOCALLY. WITH
THIS VERY STAGNANT PATTERN IN PLACE FORECAST FOCUS CONTINUES TO
BE ON HOT TEMPERATURES AND MARGINAL FIRE WEATHER CONDITIONS.
TIGHT GRADIENT IS STILL IN PLACE ACROSS OUR CWA ON EASTER EDGE OF
TEE TROUGH...HOWEVER THE MAIN TROUGH AXIS IS BEGINNING OT SHIFT
CLOSER TO THE KS/CO BORDER WHICH SHOULD HELP RELAX THE GRADIENT
ACROSS THE NW HALF OF OUR CWA. AS WOULD BE EXPECTED WITH LESS
GRADIENT IN THE NW PART OF OUR CWA...SHORT RANGE MODELS ARE
BACKING OFF ON WINDS ACROSS THE WEST...WITH GUSTY WINDS MAINLY
ACROSS OUR EASTERN CWA. LOWEST RH VALUES SHOULD BE ACROSS THE WEST
AS HAS BEEN THE CASE THE LAST FEW DAYS...AND ARE ALREADY MARGINAL
FOR RFW. THE CHANCE FOR RH/WIND CROSSOVER IS VERY LOW...SO FIRE
WEATHER HIGHLIGHT WILL NOT BE NECESSARY.
REGARDING TEMPERATURES...NAM/GFS/ECMWF ALL SHOW VERY SIMILAR
AIR MASS IN PLACE THROUGH TUESDAY WHICH MEAN THERE SHOULDNT BE A
LOT OF VARIANCE FROM UPPER 90S/LOW 100S. BETTER MIXING COULD
RESULT IN NEAR RECORD HIGHS AT A FEW LOCATIONS. I DECIDED TO KEEP
ONGOING FORECAST WITHIN A DEGREE OR TWO OF PERSISTENCE WITH LITTLE
EXPECTED TO CHANGE. THROUGH TUESDAY NIGHT. BY WEDNESDAY A
SHORTWAVE TROUGH/MID LEVEL VORTICITY MAX WILL ROTATE FROM THE
SOUTHERN PLAINS AND ACROSS WESTERN KANSAS OUT OF THE SOUTH. WHILE
LARGE SCALE ASCENT AND ELEVATED INSTABILITY ASSOCIATED WITH A
MID LEVEL COLD POOL WILL MOVE OVER THE CWA...THERE IS A
SIGNIFICANTLY DRY AIR MASS IN PLACE. BEYOND AN INCREASE IN CLOUDS I
AM NOT ANTICIPATING ANY PRECIP WITH THIS FEATURE. THIS WILL HELP
REDUCE TEMPS OVER THE CWA BY ABOUT 5-7F FOR MOST LOCATIONS...WHICH
IS A SMALL CONCESSION SINCE THIS IS STILL WELL ABOVE NORMAL.
.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 243 AM MDT MON AUG 26 2013
THE UPPER LEVEL RIDGE WILL PERSIST THROUGH THE EXTENDED PERIOD. THE
WARMEST 850 MB TEMPERATURES WILL BE ON FRIDAY AND SATURDAY RESULTING
IN HIGH TEMPERATURES IN THE UPPER 90S TO NEAR 100 DEGREES BOTH DAYS.
DIFFERENCES IN MEDIUM RANGE MODELS EMERGE OVER THE WEEKEND WITH THE
CHARACTER AND POSITION OF THE UPPER LEVEL RIDGE AND THE EASTWARD
PROGRESSION OF PACIFIC NORTHWEST TROUGH. GFS ENSEMBLE MEAN IS THE
MOST PROGRESSIVE SHIFTING BOTH FEATURES EASTWARD AND PLACING THE
AREA IN SOUTHWESTERLY FLOW ALOFT. IN CONTRAST ECMWF HOLDS THE RIDGE
OVER THE AREA WITH A SLIGHT DEAMPLIFICATION AS A SHORTWAVE TROUGH
MOVES EASTWARD ACROSS THE NORTHERN PLAINS. IN EITHER SCENARIO...A
GENERALLY DRY PATTERN WITH ABOVE NORMAL TEMPERATURES ARE LIKELY TO
PERSIST THROUGH THE WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 519 AM MDT MON AUG 26 2013
VFR CONDITIONS WILL CONTINUE THROUGH THE TAF PERIOD. THE WIND WILL
INCREASE AND BECOME GUSTY BY LATE MORNING PERSISTING THROUGH EARLY
EVENING. GUSTS TO AROUND 30 KNOTS WILL BE POSSIBLE DURING THIS
PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...BRB
AVIATION...BRB
AREA FORECAST DISCUSSION
NWS GOODLAND KS
245 AM MDT MON AUG 26 2013
.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 243 AM MDT MON AUG 26 2013
LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOW LARGE H5 598DM RIDGE
STILL IN PLACE ACROSS THE CENTRAL CONUS. WHILE THERE IS WEAK
ENERGY ROTATING AROUND THE WEST SIDE OF THE RIDGE THAT CONTINUES TO
INITIATE SHOWER/THUNDERSTORM ACTIVITY OVER THE MOUNTAINS...BEYOND
HIGH CLOUDS MOVING ACROSS THE WESTERN PART OF OUR CWA THESE WEAK
WAVES WILL NOT HAVE ANY INFLUENCE ON OUR WEATHER LOCALLY. WITH
THIS VERY STAGNANT PATTERN IN PLACE FORECAST FOCUS CONTINUES TO
BE ON HOT TEMPERATURES AND MARGINAL FIRE WEATHER CONDITIONS.
TIGHT GRADIENT IS STILL IN PLACE ACROSS OUR CWA ON EASTER EDGE OF
TEE TROUGH...HOWEVER THE MAIN TROUGH AXIS IS BEGINNING OT SHIFT
CLOSER TO THE KS/CO BORDER WHICH SHOULD HELP RELAX THE GRADIENT
ACROSS THE NW HALF OF OUR CWA. AS WOULD BE EXPECTED WITH LESS
GRADIENT IN THE NW PART OF OUR CWA...SHORT RANGE MODELS ARE
BACKING OFF ON WINDS ACROSS THE WEST...WITH GUSTY WINDS MAINLY
ACROSS OUR EASTERN CWA. LOWEST RH VALUES SHOULD BE ACROSS THE WEST
AS HAS BEEN THE CASE THE LAST FEW DAYS...AND ARE ALREADY MARGINAL
FOR RFW. THE CHANCE FOR RH/WIND CROSSOVER IS VERY LOW...SO FIRE
WEATHER HIGHLIGHT WILL NOT BE NECESSARY.
REGARDING TEMPERATURES...NAM/GFS/ECMWF ALL SHOW VERY SIMILAR
AIR MASS IN PLACE THROUGH TUESDAY WHICH MEAN THERE SHOULDNT BE A
LOT OF VARIANCE FROM UPPER 90S/LOW 100S. BETTER MIXING COULD
RESULT IN NEAR RECORD HIGHS AT A FEW LOCATIONS. I DECIDED TO KEEP
ONGOING FORECAST WITHIN A DEGREE OR TWO OF PERSISTENCE WITH LITTLE
EXPECTED TO CHANGE. THROUGH TUESDAY NIGHT. BY WEDNESDAY A
SHORTWAVE TROUGH/MID LEVEL VORTICITY MAX WILL ROTATE FROM THE
SOUTHERN PLAINS AND ACROSS WESTERN KANSAS OUT OF THE SOUTH. WHILE
LARGE SCALE ASCENT AND ELEVATED INSTABILITY ASSOCIATED WITH A
MID LEVEL COLD POOL WILL MOVE OVER THE CWA...THERE IS A
SIGNIFICANTLY DRY AIR MASS IN PLACE. BEYOND AN INCREASE IN CLOUDS I
AM NOT ANTICIPATING ANY PRECIP WITH THIS FEATURE. THIS WILL HELP
REDUCE TEMPS OVER THE CWA BY ABOUT 5-7F FOR MOST LOCATIONS...WHICH
IS A SMALL CONCESSION SINCE THIS IS STILL WELL ABOVE NORMAL.
.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 243 AM MDT MON AUG 26 2013
THE UPPER LEVEL RIDGE WILL PERSIST THROUGH THE EXTENDED PERIOD. THE
WARMEST 850 MB TEMPERATURES WILL BE ON FRIDAY AND SATURDAY RESULTING
IN HIGH TEMPERATURES IN THE UPPER 90S TO NEAR 100 DEGREES BOTH DAYS.
DIFFERENCES IN MEDIUM RANGE MODELS EMERGE OVER THE WEEKEND WITH THE
CHARACTER AND POSITION OF THE UPPER LEVEL RIDGE AND THE EASTWARD
PROGRESSION OF PACIFIC NORTHWEST TROUGH. GFS ENSEMBLE MEAN IS THE
MOST PROGRESSIVE SHIFTING BOTH FEATURES EASTWARD AND PLACING THE
AREA IN SOUTHWESTERLY FLOW ALOFT. IN CONTRAST ECMWF HOLDS THE RIDGE
OVER THE AREA WITH A SLIGHT DEAMPLIFICATION AS A SHORTWAVE TROUGH
MOVES EASTWARD ACROSS THE NORTHERN PLAINS. IN EITHER SCENARIO...A
GENERALLY DRY PATTERN WITH ABOVE NORMAL TEMPERATURES ARE LIKELY TO
PERSIST THROUGH THE WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1145 PM MDT SUN AUG 25 2013
VFR CONDITIONS WILL PERSIST THROUGH THE TAF PERIOD WITH GUSTY
SOUTH WINDS BETWEEN 15Z AND 02Z ON MONDAY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...BRB
AVIATION...LOCKHART
AREA FORECAST DISCUSSION
NWS GRAY ME
557 PM EDT MON AUG 26 2013
.SYNOPSIS...
LOW PRESSURE OVER THE EASTERN GREAT LAKES WILL TRACK INTO SOUTHERN
NEW ENGLAND TONIGHT THEN EASTWARD OFF CAPE COD ON TUESDAY. THIS
WILL LEAVE NORTHERN NEW ENGLAND IN A WARM AND HUMID AIR MASS WITH
ISOLATED SHOWERS AND THUNDERSTORMS. A WEAK DISTURBANCE WILL CROSS
THE REGION WEDNESDAY AND THURSDAY FOLLOWED BY A WEAK RIDGE OF HIGH
PRESSURE FRIDAY. A COLD FRONT WILL DROP SOUTH INTO THE REGION
FRIDAY NIGHT AND SATURDAY BEFORE RETURNING NORTH AS A WARM FRONT
FOR SUNDAY. A COLD FRONT WILL CROSS THE AREA ON MONDAY. &&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
UPDATE...
HAVE UPDATED GRIDS BASED ON CURRENT RADAR TRENDS. HAVE LOWERED
POPS OVER MAINE DURING THE EVENING HOURS TO ESSENTIALLY
ZERO...WHILE INCREASING POPS ACROSS SOUTHERN NH. LARGE AREA OF
CONVECTION WILL CONTINUE TO HEAD SOUTHEAST AS PER LATEST HRRR RUNS
SUGGEST. MOST OF THE REMAINDER OF THE AREA WILL REMAIN DRY HOWEVER
FOR MUCH OF THE NIGHT.
HAVE ALSO MADE ADJUSTMENTS TO TEMPERATURE...DEW POINT AND CLOUD
COVER FOR THE NEXT FEW HOURS. THE REST OF THE GRIDDED PACKAGE WILL
REMAIN UNCHANGED.
PREV DISC...
AFTER SOME BREAKS IN THE CLOUDS SOUTHWEST OF THE HIGHER
TERRAIN THIS AFTERNOON, CLOUDS ARE STARTING TO FILL BACK IN. SKIES
SHOULD BE PARTLY TO MOSTLY CLOUDY TONIGHT WITH DEW POINT
TEMPERATURES IN THE 60S, SO PATCHY FOG IS LIKELY. THE MESOSCALE
CONVECTIVE SYSTEM IN WESTERN NEW YORK IS LIKELY TO TRACK THROUGH
SOUTHWESTERN NEW ENGLAND THIS EVENING AND REMAIN SOUTH OF THE
FORECAST AREA. A FEW LIGHT SHOWERS ARE POSSIBLE NEAR THE
MASSACHUSETTS BORDER TOWARD DAYBREAK.
&&
.NEAR TERM /THROUGH TUESDAY/...
AFTER SOME BREAKS IN THE CLOUDS SOUTHWEST OF THE HIGHER TERRAIN
THIS AFTERNOON, CLOUDS ARE STARTING TO FILL BACK IN. SKIES SHOULD
BE PARTLY TO MOSTLY CLOUDY TONIGHT WITH DEW POINT TEMPERATURES IN
THE 60S, SO PATCHY FOG IS LIKELY. THE MESOSCALE CONVECTIVE SYSTEM
IN WESTERN NEW YORK IS LIKELY TO TRACK THROUGH SOUTHWESTERN NEW
ENGLAND THIS EVENING AND REMAIN SOUTH OF THE FORECAST AREA. A FEW
LIGHT SHOWERS ARE POSSIBLE NEAR THE MASSACHUSETTS BORDER TOWARD DAYBREAK.
&&
.SHORT TERM /TUESDAY NIGHT/...
THE WARM AND HUMID AIR MASS REMAINS IN PLACE ON TUESDAY, WITH
AMPLE INSTABILITY FOR THUNDER IN THE AFTERNOON AND EVENING -- IF
WE CAN COUNT ON THE MOUNTAINS TRIGGERING CONVECTION AS THERE
REALLY IS NO DYNAMIC FORCING EXPECTED. HAVE KEPT POPS AS LOW
CHANCE TUESDAY AND TUESDAY NIGHT WITH ONLY LIGHT PRECIPITATION
AMOUNTS EXPECTED. LOW PRESSURE BEGINS TO DEVELOP NEAR SOUTHEASTERN
NEW ENGLAND TUESDAY EVENING BUT SHOULDN`T AFFECT COASTAL NH/ME
UNTIL WEDNESDAY AT THE EARLIEST.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
THE MODELS ARE IN DECENT AGREEMENT THROUGH FRIDAY BEFORE DIFFERENCES
BEGIN TO EMERGE. THE UPPER HIGH WILL WEAKEN A BIT AND SHIFT FURTHER
WEST AS SERIES OF IMPULSES RIDE OVER THE TOP OF THE RIDGE. BY THE
END OF THE PERIOD...WE TRANSITION TO A HIGHER AMPLITUDE PATTERN
WITH A RIDGE OVER THE WEST-CENTRAL U.S. AND AN EASTERN TROUGH. WE
BEGIN THE PERIOD WITH AN IMPULSE DIVING OVER THE TOP OF THE RIDGE
INTO NEW ENGLAND FOR WEDNESDAY WITH A LINGERING TROUGH AND UNSETTLED
WEATHER INTO THURSDAY. ON FRIDAY...ONLY A SLIGHT CHANCE OF SHOWERS
AS WEAK RIDGING OCCURS AHEAD OF THE NEXT IMPULSE AND AN ASSOCIATED
COLD FRONT THAT DROPS INTO THE REGION FRIDAY NIGHT/EARLY SATURDAY
BEFORE RETURNING NORTH AS A WARM FRONT BY SUNDAY. A COLD FRONT
WILL CROSS THE AREA ON MONDAY.
&&
.AVIATION /22Z MONDAY THROUGH SATURDAY/...
SHORT TERM...MVFR CEILINGS THIS EVENING WILL GIVE WAY TO SCATTERED
IFR/LIFR IN VALLEY FOG. VFR TUESDAY AND TUESDAY NIGHT EXCEPT WHERE
FOG DEVELOPS.
LONG TERM...
WED - THU...SCT MVFR IN SHOWERS AND TSTMS.
&&
.MARINE...
SHORT TERM...WINDS AND SEAS TO REMAIN BELOW SMALL CRAFT ADVISORY
CRITERIA THROUGH WEDNESDAY.
LONG TERM...
FRI NIGHT - SAT...WINDS AND SEAS MAY APPROACH SMALL CRAFT OUTSIDE
THE BAYS.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1204 PM EDT MON AUG 26 2013
.SYNOPSIS...
WARMER AND MORE HUMID AIR FOR MUCH OF THE WEEK. A COLD FRONT WILL
BRING SHOWERS AND STORMS TUESDAY AND WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NO UPDATES MADE TO THE NEAR TERM FORECAST WITH THE NOON UPDATE.
WITH 1030AM UPDATE...MADE MANY SMALL TWEAKS TO THE FORECAST.
UPDATED HOURLY AND MAXIMUM TEMPERATURES WITH LATEST GFSLAMP
GUIDANCE...WHICH SO FAR HAS HAD A GOOD HANDLE OF TEMPERATURE
TRENDS. ALSO BACKED OFF SLIGHTLY ON THE HIGH CIRRUS MOVING IN.
WITH LATEST RUNS OF THE HRRR AND RUC SHOWING THAT ANY
PRECIPITATION THAT AFFECTS THE AREA SHOULD ARRIVE MORE TOWARDS
THE EVENING...HAVE ALSO BACKED OFF POPS SLIGHTLY DURING THE
AFTERNOON TIME PERIOD.
PREVIOUS DISC...AREA LIES ON THE EASTERN PERIPHERY OF STRONG
RIDGE OVER THE CENTRAL STATES. BECAUSE OF THIS...THE DISTRICT IS
IN A PRECARIOUS POSITION WITH NORTHWEST FLOW ALOFT. THIS WILL
BECOME IMPORTANT AS THE WEEK PROGRESSES.
FOR TODAY...THE UPPER LEVEL RIDGE HOLDS FIRM INTO THE AFTERNOON
THEN BEGINS TO RETROGRADE AS A SHORTWAVE TROUGH DIVES DOWN
THROUGH THE GREAT LAKES. THE STRONGEST PART OF THE SHORTWAVE...AND
DEEPEST MOISTURE...WILL MOVE EAST LATE THIS AFTERNOON. WAVE MAY
BE CLOSE ENOUGH TO SPARK A SHOWER OR STORM ACROSS THE NORTH AS
THE EVENING APPROACHES.
HUMIDITY LEVELS AND TEMPERATURES WILL BE ON THE RISE TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
WITH THE NOON UPDATE...HAVE BUMPED UP POPS NORTH OF PITTSBURGH FOR
TONIGHT. 12Z SYNOPTIC MODELS HAVE ALL COME IN WITH MEASURABLE
PRECIPITATION ALONG THE INTERSTATE 80 CORRIDOR...NOW COMING INTO
AGREEMENT WITH SOME OF THE 00Z HIGH-RESOLUTION MODELS. LIKELY POPS
MAY NEED TO COME FARTHER SOUTH...BUT WILL WAIT UNTIL 12Z HIGH-
RESOLUTION MODELS COME OUT TO MAKE THIS DECISION. PREVIOUS
DISCUSSION FOLLOWS.
AT THIS POINT...HAVE LOW CONFIDENCE ON HOW MUCH ACTIVITY WILL
MOVE THROUGH TONIGHT. AS MENTIONED PREVIOUSLY...MOST OF THE UPPER
LEVEL ENERGY AND DEEP MOISTURE WILL MOVE EAST OF THE AREA.
ADDITIONALLY...ATMOSPHERE STABILIZES AND THE LOW LEVEL JET DIVES
INTO EASTERN PA. MODELS ARE INDICATING SOME ACTIVITY HOLDING
TOGETHER OVERNIGHT AS PART OF THE UPPER LEVEL WAVE STRETCHES
WESTWARD. LATEST HIRES MODEL DATA IS SHOWING A LINE OF
SHOWERS/STORMS DEVELOPING ALONG LAKE ERIE THIS EVENING AND THEN
MOVING SOUTHWARD INTO EARLY TUESDAY MORNING. LOW LEVEL MOISTURE
WILL POOL OVER THE UPPER OHIO VALLEY AHEAD OF THE WAVE...BUT WOULD
THINK THAT ACTIVITY WILL DIMINISH AS IT MOVES SOUTHWARD. WILL
CONTINUE WITH THE MENTION OF SCHC/CHC POPS TONIGHT WITH THUNDER
BECOMING LESS PREVALENT LATE TONIGHT.
THIS FIRST WAVE WILL BE OUT OF THE PICTURE TUESDAY MORNING...
ALLOWING FOR A BREAK IN THE ACTIVITY. THANKS TO TONIGHT`S
WAVE...THE RIDGE WILL FURTHER RETROGRADE...PUTTING THE REGION IN
THE PATH OF A SECOND WAVE MOVING SOUTHEASTWARD TUESDAY AFTERNOON.
ATMOSPHERE BECOMES VERY UNSTABLE TUESDAY WITH CAPES OF 2000-3000
J/KG AND LI`S TO AROUND -5. THE K INDEX IS IN THE MID 30S AND THE
MDPI IS AROUND 1. IN ADDITION TO THE ENERGETIC ATMOSPHERE...
SURFACE TDS WILL BE IN THE LOWER 70S LEADING TO PWATS NEAR 1.7. IF
CONVECTION CAN GET GOING...WIND AND HEAVY RAIN WILL BE A THREAT. A
LIMITING FACTOR...PARTICULARLY EARLIER IN THE DAY...WILL BE
RESIDUAL CLOUD COVER. CONVECTIVE TEMPS REMAIN IN THE MID 80S
TUESDAY AND CLOUD COVER MAY MAKE REACHING THESE TEMPS DIFFICULT.
TUESDAYS SHORTWAVE WILL MOVE EASTWARD AND BE FOLLOWED BY ANOTHER
WAVE TUESDAY NIGHT. TUESDAY NIGHT`S WAVE COULD POSSIBLY DEVELOP AN
MCS OVER THE UPPER GREAT LAKES WHICH WOULD DROP DOWN THROUGH THE
AREA. AT THIS POINT...THINK THE GREATER THREAT TUESDAY NIGHT/EARLY
WED WOULD BE WATER RATHER THAN WIND. INSTABILITY WANES...BUT WITH
PWATS NEAR 2 INCHES...ANY CONVECTION WILL PRODUCE HEAVY DOWNPOURS.
THE THREAT FOR STRONG STORMS WILL CONTINUE THROUGH WEDNESDAY AS A
COLD FRONT SINKS THROUGH THE UPPER OHIO VALLEY.
TUESDAY AND WEDNESDAY WILL NEED TO BE CLOSELY MONITORED. IN
GENERAL...WHEN THE AREA LIES ON THE EASTERN EDGE OF A STRONG
RIDGE CAUSING NORTHWEST FLOW ALOFT...OUR WEATHER GETS VERY ACTIVE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
COLD FRONT WILL CLEAR THE AREA WEDNESDAY NIGHT. HIGH PRESSURE WILL
RESUME CONTROL FOR THE REMAINDER OF THE LONG TERM.
&&
.AVIATION /16Z MONDAY THROUGH FRIDAY/...
GENL VFR CONDS ARE EXPD THRU THIS EVE WITH INCRG MID/HIGH CLDS.
AREAS OF SHWRS AND TSTMS ASSOCIATED WITH UPR LVL DISTURBANCES WL
DROP SE ACRS THE ERN GT LKS TDA AND TNGT...HOWEVER MUCH OF THIS
SHOULD STAY N AND E OF THE PORTS. FKL/DUJ HAVE THE BEST CHC AT
SEEING A SHWR OR TSTM THIS EVE SO INCLUDED A VCSH MENTION THERE.
LWR SHWR/TSTM CHCS ELSW TNGT...SO NO MENTION OF PCPN AT OTHER
PORTS. FKL/DUJ MAY ALSO SEE A PD OF MVFR CONDS NR SUNRISE TUE
MRNG.
.OUTLOOK.../TUESDAY THROUGH FRIDAY/...
RSTRNS ARE PSBL IN SHWRS/TSTMS TUE AFTN THRU WED AS A CDFNT
CROSSES THE RGN. VFR RTNS WITH HIGH PRES THU AND FRI.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1026 AM EDT MON AUG 26 2013
.SYNOPSIS...
WARMER AND MORE HUMID AIR FOR MUCH OF THE WEEK. A COLD FRONT WILL
BRING SHOWERS AND STORMS TUESDAY AND WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WITH 1030AM UPDATE...MADE MANY SMALL TWEAKS TO THE FORECAST.
UPDATED HOURLY AND MAXIMUM TEMPERATURES WITH LATEST GFSLAMP
GUIDANCE...WHICH SO FAR HAS HAD A GOOD HANDLE OF TEMPERATURE
TRENDS. ALSO BACKED OFF SLIGHTLY ON THE HIGH CIRRUS MOVING IN.
WITH LATEST RUNS OF THE HRRR AND RUC SHOWING THAT ANY
PRECIPITATION THAT AFFECTS THE AREA SHOULD ARRIVE MORE TOWARDS
THE EVENING...HAVE ALSO BACKED OFF POPS SLIGHTLY DURING THE
AFTERNOON TIME PERIOD.
PREVIOUS DISC...AREA LIES ON THE EASTERN PERIPHERY OF STRONG
RIDGE OVER THE CENTRAL STATES. BECAUSE OF THIS...THE DISTRICT IS
IN A PRECARIOUS POSITION WITH NORTHWEST FLOW ALOFT. THIS WILL
BECOME IMPORTANT AS THE WEEK PROGRESSES.
FOR TODAY...THE UPPER LEVEL RIDGE HOLDS FIRM INTO THE AFTERNOON
THEN BEGINS TO RETROGRADE AS A SHORTWAVE TROUGH DIVES DOWN
THROUGH THE GREAT LAKES. THE STRONGEST PART OF THE SHORTWAVE...AND
DEEPEST MOISTURE...WILL MOVE EAST LATE THIS AFTERNOON. WAVE MAY
BE CLOSE ENOUGH TO SPARK A SHOWER OR STORM ACROSS THE NORTH AS
THE EVENING APPROACHES.
HUMIDITY LEVELS AND TEMPERATURES WILL BE ON THE RISE TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
AT THIS POINT...HAVE LOW CONFIDENCE ON HOW MUCH ACTIVITY WILL
MOVE THROUGH TONIGHT. AS MENTIONED PREVIOUSLY...MOST OF THE UPPER
LEVEL ENERGY AND DEEP MOISTURE WILL MOVE EAST OF THE AREA.
ADDITIONALLY...ATMOSPHERE STABILIZES AND THE LOW LEVEL JET DIVES
INTO EASTERN PA. MODELS ARE INDICATING SOME ACTIVITY HOLDING
TOGETHER OVERNIGHT AS PART OF THE UPPER LEVEL WAVE STRETCHES
WESTWARD. LATEST HIRES MODEL DATA IS SHOWING A LINE OF
SHOWERS/STORMS DEVELOPING ALONG LAKE ERIE THIS EVENING AND THEN
MOVING SOUTHWARD INTO EARLY TUESDAY MORNING. LOW LEVEL MOISTURE
WILL POOL OVER THE UPPER OHIO VALLEY AHEAD OF THE WAVE...BUT WOULD
THINK THAT ACTIVITY WILL DIMINISH AS IT MOVES SOUTHWARD. WILL
CONTINUE WITH THE MENTION OF SCHC/CHC POPS TONIGHT WITH THUNDER
BECOMING LESS PREVALENT LATE TONIGHT.
THIS FIRST WAVE WILL BE OUT OF THE PICTURE TUESDAY MORNING...
ALLOWING FOR A BREAK IN THE ACTIVITY. THANKS TO TONIGHT`S
WAVE...THE RIDGE WILL FURTHER RETROGRADE...PUTTING THE REGION IN
THE PATH OF A SECOND WAVE MOVING SOUTHEASTWARD TUESDAY AFTERNOON.
ATMOSPHERE BECOMES VERY UNSTABLE TUESDAY WITH CAPES OF 2000-3000
J/KG AND LI`S TO AROUND -5. THE K INDEX IS IN THE MID 30S AND THE
MDPI IS AROUND 1. IN ADDITION TO THE ENERGETIC ATMOSPHERE...
SURFACE TDS WILL BE IN THE LOWER 70S LEADING TO PWATS NEAR 1.7. IF
CONVECTION CAN GET GOING...WIND AND HEAVY RAIN WILL BE A THREAT. A
LIMITING FACTOR...PARTICULARLY EARLIER IN THE DAY...WILL BE
RESIDUAL CLOUD COVER. CONVECTIVE TEMPS REMAIN IN THE MID 80S
TUESDAY AND CLOUD COVER MAY MAKE REACHING THESE TEMPS DIFFICULT.
TUESDAYS SHORTWAVE WILL MOVE EASTWARD AND BE FOLLOWED BY ANOTHER
WAVE TUESDAY NIGHT. TUESDAY NIGHT`S WAVE COULD POSSIBLY DEVELOP AN
MCS OVER THE UPPER GREAT LAKES WHICH WOULD DROP DOWN THROUGH THE
AREA. AT THIS POINT...THINK THE GREATER THREAT TUESDAY NIGHT/EARLY
WED WOULD BE WATER RATHER THAN WIND. INSTABILITY WANES...BUT WITH
PWATS NEAR 2 INCHES...ANY CONVECTION WILL PRODUCE HEAVY DOWNPOURS.
THE THREAT FOR STRONG STORMS WILL CONTINUE THROUGH WEDNESDAY AS A
COLD FRONT SINKS THROUGH THE UPPER OHIO VALLEY.
TUESDAY AND WEDNESDAY WILL NEED TO BE CLOSELY MONITORED. IN
GENERAL...WHEN THE AREA LIES ON THE EASTERN EDGE OF A STRONG
RIDGE CAUSING NORTHWEST FLOW ALOFT...OUR WEATHER GETS VERY ACTIVE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
COLD FRONT WILL CLEAR THE AREA WEDNESDAY NIGHT. HIGH PRESSURE WILL
RESUME CONTROL FOR THE REMAINDER OF THE LONG TERM.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
GENL VFR CONDS ARE EXPD THRU THIS EVE WITH INCRG MID/HIGH CLDS.
AREAS OF SHWRS AND TSTMS ASSOCIATED WITH UPR LVL DISTURBANCES WL
DROP SE ACRS THE ERN GT LKS TDA AND TNGT...HOWEVER MUCH OF THIS
SHOULD STAY N AND E OF THE PORTS. FKL/DUJ HAVE THE BEST CHC AT
SEEING A SHWR OR TSTM THIS EVE SO INCLUDED A VCSH MENTION THERE.
LWR SHWR/TSTM CHCS ELSW TNGT...SO NO MENTION OF PCPN AT OTHER
PORTS. FKL/DUJ MAY ALSO SEE A PD OF MVFR CONDS NR SUNRISE TUE
MRNG.
.OUTLOOK.../TUESDAY THROUGH FRIDAY/...
RSTRNS ARE PSBL IN SHWRS/TSTMS TUE AFTN THRU WED AS A CDFNT
CROSSES THE RGN. VFR RTNS WITH HIGH PRES THU AND FRI.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1152 PM EDT TUE AUG 27 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 358 PM EDT TUE AUG 27 2013
AN AREA OF THUNDERSTORMS WILL PRECEDE THE COLD FRONT EARLY
TONIGHT. SOME STORMS MAY HAVE DAMAGING WINDS AND LARGE HAIL FROM
THESE STORMS. ALSO VERY HEAVY RAINFALL IS POSSIBLE AS THE LINE OF
STORMS MOVES THROUGH THE AREA.
A LARGE CANADIAN HIGH MOVES ACROSS THE AREA WEDNESDAY INTO
THURSDAY BEFORE ANOTHER FRONTAL WAVE MOVES THROUGH THE AREA FRIDAY
WITH A CHANCE OF SCATTERED THUNDERSTORMS. TEMPERATURES WILL
CONTINUE TO BE WARMER THAN NORMAL THROUGH SUNDAY.
&&
.UPDATE...
ISSUED AT 1005 PM EDT TUE AUG 27 2013
SVR WATCH EXPIRED AT 10 PM. CURRENT RADAR SHOWS A CLUSTER OF
STRONGER STORMS MOVING SE ACROSS MONTCALM/GRATIOT COUNTIES AND
WILL LIKELY AFFECT LANSING IN A HOUR OR SO IF THEY HOLD TOGETHER.
WIND GUSTS TO 40 MPH POSSIBLE WITH THIS CLUSTER. ELSEWHERE...MORE
SHOWERS/STORMS MOVING SE FROM WISCONSIN AND WILL AFFECT THE REST
OF SW LWR OVERNIGHT...EXCEPT THE FAR NE CWA.. KEPT HIGH POPS IN
THE GRIDS FOR THIS.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 358 PM EDT TUE AUG 27 2013
THE MAIN ISSUE WITH THIS FORECAST IS THE RISK OF STRONG TO SEVERE
STORMS EARLY THIS EVENING AND ALSO THE POTENTIAL FOR FLOODING AS
THE ATMOSPHERE IS VERY MOIST AHEAD OF THE COLD FRONT.
THE COMBINATION OF SHORTWAVE... AN 80 KNOT SPEED MAX ON THE POLAR
JET DIVING SOUTHEAST ACROSS LAKE HURON...AN ASSOCIATED 30 KNOT
LOW LEVEL JET NEAR AND SOUTH OF INTERSTATE 96 FEEDING INTO THE
ASSOCIATED FRONTAL WAVE DIVING SOUTHEAST FROM EASTERN MINNESOTA
WILL FEED ON THE 250O J/KG OF MIXED LAYER CAPE OVER SOUTHERN AND
CENTRAL LOWER MICHIGAN THIS EVENING TO BRING THE POTENTIAL FOR
STRONG TO SEVERE STORMS THIS EVENING OVER MOST OF SOUTHWEST LOWER
MICHIGAN. THERE IS A DIFFERENTIAL HEATING BOUNDARY NEAR ROUTE
10...SOUTH OF WHICH ANY STORMS WOULD BE SURFACE BASED THIS
EVENING. AS THE LINE OF STORMS OVER NORTHWEST LOWER MICHIGAN MOVES
SOUTH OF ROUTE 10 I WOULD EXPECT THE STORMS TO INTENSIFY. WHILE
THE SURFACE WINDS ARE NOT ALL THAT STRONG INTO THE FRONT... THERE
IS A DRY LAYER OF AIR BELOW 800 MB...SEEN ON BOTH THE RAP AND NAM
SOUNDINGS THAT WOULD SUPPORT VERY STRONG WINDS FROM THESE STORMS.
ALSO THERE IS THE THREAT FOR LOCALIZED FLOODING AS PRECIPITABLE
WATER VALUES ARE OVER 2 INCHES WHICH IS MORE THAN 2 STANDARD
DEVIATIONS FROM NORMAL. SO EVEN THROUGH THE STORMS WILL BE MOVING
AROUND 35 TO 40 KNOTS...THE RAIN MAY BE HEAVY ENOUGH TO CAUSE
FLOODING IN URBAN AREA OR AREAS WITH POOR DRAINAGE. ALSO MOST OF
OUR NORTHERN CWA HAD OVER A HALF INCH OF RAIN LAST NIGHT...SOME
AREAS HAD OVER 1 1/2 INCHES SO THE SOIL IS RATHER WET THERE
ALREADY.
ONCE THE STORMS MOVE THROUGH LATER THIS EVENING DRIER AIR MOVES IN
BEHIND THE FRONT BUT THERE IS SOME LOW LEVEL MOISTURE THAT WRAPS
AROUND THE SYSTEM SO EVEN THROUGH THE STORMS SHOULD END... THE
REAL CLEARING OF THE SKY MY TAKE UNTIL MID DAY WEDNESDAY.
HIGH PRESSURE WILL BRING MOSTLY CLEAR SKIES AND LOWER DEW POINTS
WEDNESDAY NIGHT INTO THURSDAY. ANOTHER FRONTAL WAVE MAY BRING MORE
THUNDERSTORMS TO THE AREA LATER THURSDAY NIGHT.
.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 358 PM EDT TUE AUG 27 2013
UNSEASONABLY WARM AND HUMID CONDITIONS ARE ANTICIPATED FRIDAY AND
SATURDAY. THERE IS A SMALL CHC OF A SHOWER OR STORM FRIDAY AS A WEAK
SHORTWAVE MAY MOVE IN FROM THE WNW AND COMBINE WITH WEAK INSTABILITY
TO CAUSE DEVELOPMENT OF A SHOWER OR TWO.
A BETTER CHANCE FOR SHOWERS AND STORMS SHOULD COME SATURDAY THROUGH
SATURDAY NIGHT ALONG AND OUT AHEAD OF THE APPROACHING COLD FRONT. NW
FLOW CAA WILL COMMENCE BEHIND THE FRONT ON SUNDAY BUT MAX TEMPS
SUNDAY SHOULD STILL REACH THE UPPER 70S TO LOWER 80S. HOWEVER BY
LABOR DAY AND FOR TUESDAY IT WILL BE MUCH COOLER WITH MAX TEMPS
LIKELY STRUGGLING TO REACH THE LOWER 70S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1152 PM EDT TUE AUG 27 2013
SHOWERS AND THUNDERSTORMS WILL BE MOVE SOUTH OF LOWER MICHIGAN BY
08Z BUT IFR AND LIFR CONDITIONS ARE EXPECTED TO DEVELOP AS LOW
LEVEL MOISTURE PERSISTS INTO WEDNESDAY MORNING. THE LOW CLOUDS
SHOULD BEGIN TO BREAK UP DURING THE MORNING WITH VFR EXPECTED BY
AFTERNOON.
&&
.MARINE...
ISSUED AT 358 PM EDT TUE AUG 27 2013
WINDS SHOULD BECOME NORTH AND BE ON THE LIGHT SIDE BEHIND THE
COLD FRONT WEDNESDAY INTO THURSDAY SO I DO NOT SEE MUCH OF AN
ISSUE WITH HAVING TO HAVE A SMALL CRAFT ADVISORY AT THIS POINT.
&&
.HYDROLOGY...
ISSUED AT 358 PM EDT TUE AUG 27 2013
GIVEN THE HIGH PRECIPITABLE WATER VALUES IN THE ATMOSPHERE AHEAD
OF THE COLD FRONT THERE IS THE POTENTIAL FOR FLOODING OF AREAS
WITH POOR DRAINAGE. SOME LOCALIZED AREAS COULD SEE OVER AN INCH OF
RAIN IN LESS THAN AN HOUR WITH THE STRONGER STORMS... THAT SORT OF
RAINFALL RATE WOULD BE A PROBLEM IN URBAN AREA.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...93
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...LAURENS
AVIATION...OSTUNO
HYDROLOGY...WDM
MARINE...WDM
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1008 PM EDT TUE AUG 27 2013
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 358 PM EDT TUE AUG 27 2013
AN AREA OF THUNDERSTORMS WILL PRECEDE THE COLD FRONT EARLY
TONIGHT. SOME STORMS MAY HAVE DAMAGING WINDS AND LARGE HAIL FROM
THESE STORMS. ALSO VERY HEAVY RAINFALL IS POSSIBLE AS THE LINE OF
STORMS MOVES THROUGH THE AREA.
A LARGE CANADIAN HIGH MOVES ACROSS THE AREA WEDNESDAY INTO
THURSDAY BEFORE ANOTHER FRONTAL WAVE MOVES THROUGH THE AREA FRIDAY
WITH A CHANCE OF SCATTERED THUNDERSTORMS. TEMPERATURES WILL
CONTINUE TO BE WARMER THAN NORMAL THROUGH SUNDAY.
&&
.UPDATE...
ISSUED AT 1005 PM EDT TUE AUG 27 2013
SVR WATCH EXPIRED AT 10 PM. CURRENT RADAR SHOWS A CLUSTER OF
STRONGER STORMS MOVING SE ACROSS MONTCALM/GRATIOT COUNTIES AND
WILL LIKELY AFFECT LANSING IN A HOUR OR SO IF THEY HOLD TOGETHER.
WIND GUSTS TO 40 MPH POSSIBLE WITH THIS CLUSTER. ELSEWHERE...MORE
SHOWERS/STORMS MOVING SE FROM WISCONSIN AND WILL AFFECT THE REST
OF SW LWR OVERNIGHT...EXCEPT THE FAR NE CWA.. KEPT HIGH POPS IN
THE GRIDS FOR THIS.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 358 PM EDT TUE AUG 27 2013
THE MAIN ISSUE WITH THIS FORECAST IS THE RISK OF STRONG TO SEVERE
STORMS EARLY THIS EVENING AND ALSO THE POTENTIAL FOR FLOODING AS
THE ATMOSPHERE IS VERY MOIST AHEAD OF THE COLD FRONT.
THE COMBINATION OF SHORTWAVE... AN 80 KNOT SPEED MAX ON THE POLAR
JET DIVING SOUTHEAST ACROSS LAKE HURON...AN ASSOCIATED 30 KNOT
LOW LEVEL JET NEAR AND SOUTH OF INTERSTATE 96 FEEDING INTO THE
ASSOCIATED FRONTAL WAVE DIVING SOUTHEAST FROM EASTERN MINNESOTA
WILL FEED ON THE 250O J/KG OF MIXED LAYER CAPE OVER SOUTHERN AND
CENTRAL LOWER MICHIGAN THIS EVENING TO BRING THE POTENTIAL FOR
STRONG TO SEVERE STORMS THIS EVENING OVER MOST OF SOUTHWEST LOWER
MICHIGAN. THERE IS A DIFFERENTIAL HEATING BOUNDARY NEAR ROUTE
10...SOUTH OF WHICH ANY STORMS WOULD BE SURFACE BASED THIS
EVENING. AS THE LINE OF STORMS OVER NORTHWEST LOWER MICHIGAN MOVES
SOUTH OF ROUTE 10 I WOULD EXPECT THE STORMS TO INTENSIFY. WHILE
THE SURFACE WINDS ARE NOT ALL THAT STRONG INTO THE FRONT... THERE
IS A DRY LAYER OF AIR BELOW 800 MB...SEEN ON BOTH THE RAP AND NAM
SOUNDINGS THAT WOULD SUPPORT VERY STRONG WINDS FROM THESE STORMS.
ALSO THERE IS THE THREAT FOR LOCALIZED FLOODING AS PRECIPITABLE
WATER VALUES ARE OVER 2 INCHES WHICH IS MORE THAN 2 STANDARD
DEVIATIONS FROM NORMAL. SO EVEN THROUGH THE STORMS WILL BE MOVING
AROUND 35 TO 40 KNOTS...THE RAIN MAY BE HEAVY ENOUGH TO CAUSE
FLOODING IN URBAN AREA OR AREAS WITH POOR DRAINAGE. ALSO MOST OF
OUR NORTHERN CWA HAD OVER A HALF INCH OF RAIN LAST NIGHT...SOME
AREAS HAD OVER 1 1/2 INCHES SO THE SOIL IS RATHER WET THERE
ALREADY.
ONCE THE STORMS MOVE THROUGH LATER THIS EVENING DRIER AIR MOVES IN
BEHIND THE FRONT BUT THERE IS SOME LOW LEVEL MOISTURE THAT WRAPS
AROUND THE SYSTEM SO EVEN THROUGH THE STORMS SHOULD END... THE
REAL CLEARING OF THE SKY MY TAKE UNTIL MID DAY WEDNESDAY.
HIGH PRESSURE WILL BRING MOSTLY CLEAR SKIES AND LOWER DEW POINTS
WEDNESDAY NIGHT INTO THURSDAY. ANOTHER FRONTAL WAVE MAY BRING MORE
THUNDERSTORMS TO THE AREA LATER THURSDAY NIGHT.
.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 358 PM EDT TUE AUG 27 2013
UNSEASONABLY WARM AND HUMID CONDITIONS ARE ANTICIPATED FRIDAY AND
SATURDAY. THERE IS A SMALL CHC OF A SHOWER OR STORM FRIDAY AS A WEAK
SHORTWAVE MAY MOVE IN FROM THE WNW AND COMBINE WITH WEAK INSTABILITY
TO CAUSE DEVELOPMENT OF A SHOWER OR TWO.
A BETTER CHANCE FOR SHOWERS AND STORMS SHOULD COME SATURDAY THROUGH
SATURDAY NIGHT ALONG AND OUT AHEAD OF THE APPROACHING COLD FRONT. NW
FLOW CAA WILL COMMENCE BEHIND THE FRONT ON SUNDAY BUT MAX TEMPS
SUNDAY SHOULD STILL REACH THE UPPER 70S TO LOWER 80S. HOWEVER BY
LABOR DAY AND FOR TUESDAY IT WILL BE MUCH COOLER WITH MAX TEMPS
LIKELY STRUGGLING TO REACH THE LOWER 70S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 735 PM EDT TUE AUG 27 2013
SHOWERS AND THUNDERSTORMS THIS EVENING SHOULD REMAIN LARGELY TO
THE EAST OF MKG AND AZO WITH VFR PREVAILING THROUGH THE EVENING.
IFR AND LIFR CONDITIONS ARE EXPECTED AFTER MIDNIGHT AS LOW LEVEL
MOISTURE INCREASES AND PERSISTS INTO WEDNESDAY MORNING. THE LOW
CLOUDS SHOULD BEGIN TO BREAK UP DURING THE MORNING WITH VFR
EXPECTED BY AFTERNOON.
&&
.MARINE...
ISSUED AT 358 PM EDT TUE AUG 27 2013
WINDS SHOULD BECOME NORTH AND BE ON THE LIGHT SIDE BEHIND THE
COLD FRONT WEDNESDAY INTO THURSDAY SO I DO NOT SEE MUCH OF AN
ISSUE WITH HAVING TO HAVE A SMALL CRAFT ADVISORY AT THIS POINT.
&&
.HYDROLOGY...
ISSUED AT 358 PM EDT TUE AUG 27 2013
GIVEN THE HIGH PRECIPITABLE WATER VALUES IN THE ATMOSPHERE AHEAD
OF THE COLD FRONT THERE IS THE POTENTIAL FOR FLOODING OF AREAS
WITH POOR DRAINAGE. SOME LOCALIZED AREAS COULD SEE OVER AN INCH OF
RAIN IN LESS THAN AN HOUR WITH THE STRONGER STORMS... THAT SORT OF
RAINFALL RATE WOULD BE A PROBLEM IN URBAN AREA.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
UPDATE...93
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...LAURENS
AVIATION...OSTUNO
HYDROLOGY...WDM
MARINE...WDM
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
735 PM EDT TUE AUG 27 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 358 PM EDT TUE AUG 27 2013
AN AREA OF THUNDERSTORMS WILL PRECEDE THE COLD FRONT EARLY
TONIGHT. SOME STORMS MAY HAVE DAMAGING WINDS AND LARGE HAIL FROM
THESE STORMS. ALSO VERY HEAVY RAINFALL IS POSSIBLE AS THE LINE OF
STORMS MOVES THROUGH THE AREA.
A LARGE CANADIAN HIGH MOVES ACROSS THE AREA WEDNESDAY INTO
THURSDAY BEFORE ANOTHER FRONTAL WAVE MOVES THROUGH THE AREA FRIDAY
WITH A CHANCE OF SCATTERED THUNDERSTORMS. TEMPERATURES WILL
CONTINUE TO BE WARMER THAN NORMAL THROUGH SUNDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 358 PM EDT TUE AUG 27 2013
THE MAIN ISSUE WITH THIS FORECAST IS THE RISK OF STRONG TO SEVERE
STORMS EARLY THIS EVENING AND ALSO THE POTENTIAL FOR FLOODING AS
THE ATMOSPHERE IS VERY MOIST AHEAD OF THE COLD FRONT.
THE COMBINATION OF SHORTWAVE... AN 80 KNOT SPEED MAX ON THE POLAR
JET DIVING SOUTHEAST ACROSS LAKE HURON...AN ASSOCIATED 30 KNOT
LOW LEVEL JET NEAR AND SOUTH OF INTERSTATE 96 FEEDING INTO THE
ASSOCIATED FRONTAL WAVE DIVING SOUTHEAST FROM EASTERN MINNESOTA
WILL FEED ON THE 250O J/KG OF MIXED LAYER CAPE OVER SOUTHERN AND
CENTRAL LOWER MICHIGAN THIS EVENING TO BRING THE POTENTIAL FOR
STRONG TO SEVERE STORMS THIS EVENING OVER MOST OF SOUTHWEST LOWER
MICHIGAN. THERE IS A DIFFERENTIAL HEATING BOUNDARY NEAR ROUTE
10...SOUTH OF WHICH ANY STORMS WOULD BE SURFACE BASED THIS
EVENING. AS THE LINE OF STORMS OVER NORTHWEST LOWER MICHIGAN MOVES
SOUTH OF ROUTE 10 I WOULD EXPECT THE STORMS TO INTENSIFY. WHILE
THE SURFACE WINDS ARE NOT ALL THAT STRONG INTO THE FRONT... THERE
IS A DRY LAYER OF AIR BELOW 800 MB...SEEN ON BOTH THE RAP AND NAM
SOUNDINGS THAT WOULD SUPPORT VERY STRONG WINDS FROM THESE STORMS.
ALSO THERE IS THE THREAT FOR LOCALIZED FLOODING AS PRECIPITABLE
WATER VALUES ARE OVER 2 INCHES WHICH IS MORE THAN 2 STANDARD
DEVIATIONS FROM NORMAL. SO EVEN THROUGH THE STORMS WILL BE MOVING
AROUND 35 TO 40 KNOTS...THE RAIN MAY BE HEAVY ENOUGH TO CAUSE
FLOODING IN URBAN AREA OR AREAS WITH POOR DRAINAGE. ALSO MOST OF
OUR NORTHERN CWA HAD OVER A HALF INCH OF RAIN LAST NIGHT...SOME
AREAS HAD OVER 1 1/2 INCHES SO THE SOIL IS RATHER WET THERE
ALREADY.
ONCE THE STORMS MOVE THROUGH LATER THIS EVENING DRIER AIR MOVES IN
BEHIND THE FRONT BUT THERE IS SOME LOW LEVEL MOISTURE THAT WRAPS
AROUND THE SYSTEM SO EVEN THROUGH THE STORMS SHOULD END... THE
REAL CLEARING OF THE SKY MY TAKE UNTIL MID DAY WEDNESDAY.
HIGH PRESSURE WILL BRING MOSTLY CLEAR SKIES AND LOWER DEW POINTS
WEDNESDAY NIGHT INTO THURSDAY. ANOTHER FRONTAL WAVE MAY BRING MORE
THUNDERSTORMS TO THE AREA LATER THURSDAY NIGHT.
.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 358 PM EDT TUE AUG 27 2013
UNSEASONABLY WARM AND HUMID CONDITIONS ARE ANTICIPATED FRIDAY AND
SATURDAY. THERE IS A SMALL CHC OF A SHOWER OR STORM FRIDAY AS A WEAK
SHORTWAVE MAY MOVE IN FROM THE WNW AND COMBINE WITH WEAK INSTABILITY
TO CAUSE DEVELOPMENT OF A SHOWER OR TWO.
A BETTER CHANCE FOR SHOWERS AND STORMS SHOULD COME SATURDAY THROUGH
SATURDAY NIGHT ALONG AND OUT AHEAD OF THE APPROACHING COLD FRONT. NW
FLOW CAA WILL COMMENCE BEHIND THE FRONT ON SUNDAY BUT MAX TEMPS
SUNDAY SHOULD STILL REACH THE UPPER 70S TO LOWER 80S. HOWEVER BY
LABOR DAY AND FOR TUESDAY IT WILL BE MUCH COOLER WITH MAX TEMPS
LIKELY STRUGGLING TO REACH THE LOWER 70S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 735 PM EDT TUE AUG 27 2013
SHOWERS AND THUNDERSTORMS THIS EVENING SHOULD REMAIN LARGELY TO
THE EAST OF MKG AND AZO WITH VFR PREVAILING THROUGH THE EVENING.
IFR AND LIFR CONDITIONS ARE EXPECTED AFTER MIDNIGHT AS LOW LEVEL
MOISTURE INCREASES AND PERSISTS INTO WEDNESDAY MORNING. THE LOW
CLOUDS SHOULD BEGIN TO BREAK UP DURING THE MORNING WITH VFR
EXPECTED BY AFTERNOON.
&&
.MARINE...
ISSUED AT 358 PM EDT TUE AUG 27 2013
WINDS SHOULD BECOME NORTH AND BE ON THE LIGHT SIDE BEHIND THE
COLD FRONT WEDNESDAY INTO THURSDAY SO I DO NOT SEE MUCH OF AN
ISSUE WITH HAVING TO HAVE A SMALL CRAFT ADVISORY AT THIS POINT.
&&
.HYDROLOGY...
ISSUED AT 358 PM EDT TUE AUG 27 2013
GIVEN THE HIGH PRECIPITABLE WATER VALUES IN THE ATMOSPHERE AHEAD
OF THE COLD FRONT THERE IS THE POTENTIAL FOR FLOODING OF AREAS
WITH POOR DRAINAGE. SOME LOCALIZED AREAS COULD SEE OVER AN INCH OF
RAIN IN LESS THAN AN HOUR WITH THE STRONGER STORMS... THAT SORT OF
RAINFALL RATE WOULD BE A PROBLEM IN URBAN AREA.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...LAURENS
AVIATION...OSTUNO
HYDROLOGY...WDM
MARINE...WDM
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
721 PM EDT TUE AUG 27 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 428 PM EDT TUE AUG 27 2013
WV IMAGERY AND RUC ANALYSIS INDICATED WNW FLOW THROUGH THE NRN GREAT
LAKES ATOP A MID/UPPER LEVEL RIDGE CENTERED OVER MO/KS/AR. NO
SHORTWAVE TROUGHS WERE NOTED UPSTREAM THAT ARE LIKELY TO HAVE A
SIGNIFICANT AFFECT ON UPPER MICHIGAN. AT THE SFC...A WEAK
TROUGH/FRONT EXTENDED FROM NEAR MNM TO MSP WITH WEAK HIGH PRES TO
THE NW OF LAKE SUPERIOR BRINGING LIGHT NE LOW LEVEL FLOW ACROSS LAKE
SUPERIOR. PERSISTENT LOW CLOUDS OVER THE SRN HLF OF THE CWA...HAVE LIMITED
TEMPS AND RESULTANT INSTABILITY DESPITE DEWPOINTS REMAINING AROUND
70. THE LAKE BREEZE FRONT INTO NRN UPPER MI HAS PRODUCED MAINLY JUST
TCU WITH ONLY A FEW SPRINKLES. WHILE THE TSRA ALONG THE 900-700 MB
FGEN ZONE THROUGH S CNTRL UPPER MI HAD MOVED INTO NRN LAKE
MI...ADDITIONAL TSRA WERE DEVELOPING IN NE WI JUST TO THE NORTH OF
THE FRONT WHERE MLCAPE VALUES HAD CLIMBED INTO THE 2K-3K J/KG RANGE.
EXPECT MAINLY JUST ISOLD SHRA AND POSSIBLY A TSRA OVER CNTRL UPPER
MI ALONG THE LAKE BREEZE BOUNDARY LATE THIS AFTERNOON AND EVENING
WHERE INSTABILITY WAS MORE MODEST...ONLY TO NEAR 500-1000 J/KG. THE
STRONGER TSRA ALONG THE FRONT MAY JUST BRUSH THE FAR SRN CWA NEAR
MNM EARLY BUT SHOULD SAG SOUTH OF THE AREA BY 21Z-22Z. ADDITIONAL
ELEVATED SHRA/TSRA NEAR ESC LATE THIS AFTERNOON IN THE AREA OF
WAA/ISENTROPIC LIFT SHOULD ALSO MOVE OFF TO THE SE BY THIS EVENING.
LARGER SCALE SUBSIDENCE WILL THEN TAKE OVER TONIGHT AS WEAK TO
MODERATE 700-300 MB QVECTOR DIV AND SFC HIGH PRES BUILDS OVER THE
AREA. WITH THE LIGHT WINDS AND ABUNDANT LOW LEVEL MOISTURE...AREAS
OF FOG/STRATUS ARE EXPECTED TO DEVELOP. WITH ONLY WEAK DRY ADVECTION
AND DEWPOINTS ONLY DROPPING INTO THE LOWER TO MID 60S...MIN TEMPS
WILL REMAIN WELL ABOVE NORMAL. THE NNE LOW LEVEL FLOW TONIGHT INTO
EARLY WED COULD ALSO BRING FOG/STRATUS INTO LOCATIONS ALONG LAKE
SUPERIOR. AFTER DAYTIME HEATING BURNS OFF ANY LINGERING LOW
CLOUDS...SUNSHINE SHOULD PUSH INLAND TEMPS INTO THE LOWER TO MID 80S
WITH LOWER READINGS IN THE MID TO UPPER 70S ALONG LAKE SUPERIOR.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 428 PM EDT TUE AUG 27 2013
SFC HIGH OVERHEAD WEDNESDAY NIGHT SLOWLY SINKING SE THROUGH
FRIDAY...AS A WEAK FRONTAL TROUGH LINGERS ACROSS CENTRAL AND S
ONTARIO. WEDNESDAY NIGHT INTO THURSDAY MORNING STILL LOOK DRY...OUT
AHEAD OF THE NEXT SHORTWAVE OVER S ONTARIO ROUNDING THE SIGNIFICANT
RIDGE DOMINATING MUCH OF THE CENTRAL U.S. IT STILL LOOKS LIKE THE
BEST CHANCE FOR CONVECTION AND MODERATE RAIN WILL BE ALONG AND S OF
THE WI BORDER THURSDAY NIGHT.
LARGE HIGH PRESSURE OVER CENTRAL CANADA WILL SHIFT ACROSS N
ONTARIO ON FRIDAY...LEAVING UPPER MI IN BETWEEN -2 TO -6C AIR OVER S
HUDSON BAY HOTTER 22-25C TEMPERATURES OVER THE CENTRAL PLAINS. WITH
A SERIES OF WEAKER DISTURBANCES SWINGING IN FROM THE NW IT WILL BE
DIFFICULT TO KEEP THE MENTION OF SHOWERS AND THUNDERSTORMS OUT OF
THE FCST FOR FRIDAY AND FRIDAY NIGHT...ALTHOUGH THE LATEST MODEL
GUIDANCE DOES SUGGEST THAT IT COULD BE TRIMMED BACK A BIT MORE THAN
MY LAST MINUTE 20Z UPDATE.
THE SFC LOW CENTERED OVER THE PLAINS WILL SINK TO OUR S ON SATURDAY.
THIS WILL RESTRICT MUCH OF THE HOTTER AIR FROM PUSH ACROSS THE UPPER
GREAT LAKES. THE MAIN STORY WILL BE THE DEEPENING SFC LOW OVER LAKE
WINNIPEG FRIDAY NIGHT/SATURDAY MORNING MOVING ACROSS CENTRAL AND S
ONTARIO SATURDAY NIGHT /BOTTOMING OUT PRESSURE WISE AROUND 997MB/.
THE COLD FRONT IS EXPECTED TO DRAG ACROSS W AND CENTRAL UPPER MI
OVERNIGHT...AND EXIT E UPPER MI SUNDAY MORNING.
THE 27/00Z ECMWF LOOKS TO BE QUICKER AND DEEPER STILL WITH THE
TIMING OF THE 500MB TROUGH SWINGING ACROSS S CENTRAL CANADA AND
SUPPRESSING THE DOMINANT RIDGE TO THE 4-CORNERS REGION...AND IS A
SIGNIFICANT OUTLIER COMPARED TO THE GFS ENSEMBLE MEMBERS. WITH THE
TROUGH FORMING A FULL-FLEDGED LOW OVER SE CANADA MONDAY/MONDAY
NIGHT...UPPER MI WILL BE ABLE TO GET SOME RELIEF FROM THE HEAT.
SINGLE DIGIT 850MB TEMPS WILL SLIDE IN SUNDAY NIGHT...WITH BOTH 12Z
RUNS OF THE ECMWF AND GFS SHOWING 4C MONDAY MORNING.
THE COOLER TEMPERATURES WILL BE SHORT LIVED AS THE HIGH AMPLITUDE
500MB RIDGE OVER THE SOUTHERN STATES EXTENDS ACROSS THE ROCKIES ON
MONDAY...AND PUSHES ACROSS THE N PLAINS/S CENTRAL CANADA AND EDGES
ACROSS THE UPPER GREAT LAKES ON TUESDAY. LOOK FOR 70S AND POSSIBLY
80S TO RETURN AGAIN BY THE MIDDLE OF NEXT WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 721 PM EDT TUE AUG 27 2013
WITH A WARM AND HUMID AIRMASS IN PLACE TONIGHT...EXPECT LIFR/VLIFR
CONDITIONS TO REFORM AT ALL SITES WITH FOG CAUSED BY SOME UPSLOPE
FLOW. MIXING AND HEATING WILL DISSIPATE THE FOG EARLY WED MORNING
AND CONDITIONS AT ALL SITES WILL RAPIDLY GO BACK TO VFR THROUGH THE
REST OF THE FORECAST PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 428 PM EDT TUE AUG 27 2013
LIMITED PRESSURE GRADIENTS ACROSS LAKE SUPERIOR SHOULD KEEP WINDS
BELOW 20KTS THROUGH THE FORECAST PERIOD. AREAS OF FOG WILL PERSIST
ACROSS MUCH OF LAKE SUPERIOR WITH HIGH DEWPOINTS OVER THE REGION.
AS WINDS TURN TO THE NORTH TONIGHT...EXPECT THE FOG TO PUSH SOUTH
THROUGH WEDNESDAY MORNING AND THEN DIMINISH SOME AS SLIGHTLY DRIER
CANADIAN AIR MOVES SOUTH OVER THE LAKE THROUGH WEDNESDAY NIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
440 PM EDT MON AUG 26 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 418 PM EDT MON AUG 26 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE
CENTERED OVER MO/KS RESULTING IN ACYC FLOW FROM THE NRN PLAINS
THROUGH THE UPPER MS VALLEY INTO THE GREAT LAKES. WAA IN ADVANCE OF
AN UPSTREAM SHORTWAVE TROUGH MOVING INTO SW NORTH DAKOTA SUPPORTED
AN AREA OF LIGHT TO MODERATE RAIN WITH ONLY ISOLD TSRA. AT THE
SFC...THE CONVECTION THIS MORNING HELPED PUSH THE WEAK FRONTAL
BOUNDARY INTO NRN WI AND EXTENDED FROM NEAR HYR TO GRB. TEMPS TO THE
SOUTH OF THE FRONT HAVE AGAIN CLIMBED TO AROUND 90 WHILE MORE
MODERATE READINGS IN THE LOW TO MID 80S PREVAILED TO THE NORTH.
DEWPOINTS THROUGH THE REGION WERE NEAR 70F WITH 12Z OBSERVED AND
FCST SOUNDINGS SHOWING PWAT VALUES AROUND 2.0 INCHES(200 PCT OF
NORMAL).
EXPECT THAT AS THE ND SHRTWV MOVES TO THE EAST AND WAA INCREASES
THIS EVENING...EXPECT SHRA/TSRA TO DEVELOP AND QUICKLY IN INCREASE
IN COVERAGE BY LATE EVENING IN THE VCNTY OF THE SFC-800 MB FRONT
FROM CNTRL MN INTO NW WI. EVEN THOUGH THE MODELS HAVE TRENDED
FARTHER SOUTH WITH THE PCPN AND SHOW THE MOST FAVORABLE 310K
ISENTROPIC LIFT REMAINING SOUTH OF THE CWA...THERE IS STILL
CONSIDERABLE UNCERTAINTY ON THE LOCATION OF THE STRONGEST CONVECTION.
MOST OF THE HIGHER RES MODELS KEEP NEARLY ALL THE PCPN SOUTH OF
THE CWA WHILE THE GFS/ECMWF AND HIGH RES RAPID REFRESH BRING PCPN
THROUGH MAINLY THE SW HALF OF THE CWA. SO...THE HIGHER POPS/QPF WERE
SHIFTED TO THE SOUTH WITH LOCATIONS ALONG THE WI BORDER SEEING THE
GREATEST POTENTIAL FOR STRONG TSRA.
WITH MUCAPE VALUES INTO THE 1000-1500 J/KG RANGE AND EFFECTIVE SHEAR
TO AROUND 30 KT...THERE IS THE POTENTIAL FOR MULTICELL CLUSTERS THAT
COULD PRODUCE VERY HEAVY RAIN AND LCL WIND DAMAGE...SIMILAR TO LAST
NIGHT. FCST CORFIDI VECTORS SUGGEST THAT STORM ELEMENTS SHOULD KEEP
ENOUGH FORWARD MOTION TO LIMIT POTENTIAL FOR EXCESSIVE RAINFALL.
HOWEVER...ONE TO TWO INCHES AMOUNTS MAY AGAIN BE COMMON ALONG THE
PATH OF HEAVIER CLUSTERS. ANY LEFTOVER SHRA/TSRA TUE MORNING OVER
MAINLY THE S CNTRL CWA IS EXPECTED TO DIMINISH AND SAG OFF TO THE SE
BY EARLY TO MID AFTERNOON.
WITH 850 MB TEMPS REMAINING AROUND 18C...MAX TEMPS SHOULD ALSO BE
SIMILAR TO TODAY WITH HIGHS INTO THE LOW TO MID 80S WITH SLIGHTLY
COOLER READINGS ALONG THE GREAT LAKES.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 439 PM EDT MON AUG 26 2013
NO SIGNIFICANT RELIEF FROM THE WARM WEATHER. AVERAGE HIGH
TEMPERATURES THIS TIME OF YEAR ARE IN THE MID 70S FOR MUCH OF UPPER
MICHIGAN. TEMPERATURES SHOULD REMAIN 5-10F ABOVE NORMAL THROUGH THE
WEEKEND. WE CAN BASICALLY EXPECT QUIET WEATHER UNTIL THURSDAY
NIGHT...AS THE DOMINANT 500MB HIGH REMAINS OVER MUCH OF THE CENTRAL
AND SOUTHERN U.S. THE NEXT SHORTWAVE TO ROUND THE RIDGE IS CURRENTLY
MOVING IN OVER THE SW STATES...ALONG THE BAJA AND S CA SHORE THIS
AFTERNOON...HELPING PRODUCE A STRING OF SHOWERS AND A FEW
THUNDERSTORMS.
THE SHORTWAVE WILL TOP THE RIDGE ACROSS ND WEDNESDAY
AFTERNOON/EVENING...BEFORE PUSHING INTO N MN WEDNESDAY NIGHT/EARLY
THURSDAY. KEPT THE MENTION OF CHANCE RA AND SLIGHT CHANCE TS IN THE
FCST FOR THE FAR W THURSDAY AFTERNOON...SLIDING OVERHEAD THURSDAY
NIGHT...AND ENDING FRIDAY.
ANOTHER GOOD CHANCE OF SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE
SATURDAY AFTERNOON/EVENING THROUGH THE REST OF THE WEEKEND...IN
ADVANCE OF A DEEPENING SFC LOW ACROSS S CENTRAL CANADA. EXPECT THE
LOW TO SLIDE INTO ONTARIO SATURDAY NIGHT...AND EXIT INTO QUEBEC
SUNDAY AFTERNOON /AS SHOWN ON THE 26/12 ECMWF/. THE GFS IS ROUGHLY
12HRS SLOWER. BEHIND THE COLD FRONT THERE WILL LIKELY BE A
COOL-DOWN. IF NOTHING ELSE A TEMPORARY RETURN TO NEAR NORMAL
TEMPERATURES LOOK LIKELY MONDAY AFTERNOON. THE OPERATIONAL ECMWF
CAME IN WITH UPPER 50S TO MID 60S ON COOL NW FLOW. WHILE 50S DO NOT
LOOK ALL THAT LIKELY MID 60S WILL BE POSSIBLE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 143 PM EDT MON AUG 26 2013
A SFC TROUGH/VERY WEAK COLD FRONT THAT TRIGGERED SHRA/TSRA EARLIER
THIS MORNING HAS MOVED SOUTH INTO NORTHERN WISCONSIN. EXPECT MOSTLY
DRY/VFR CONDITIONS INTO THIS EVENING THEN LATER TONIGHT MORE
SHRA/TSRA COULD IMPACT THE REGION YET AGAIN. HOWEVER...THE BEST
CHANCE OF SHRA/TSRA IS EXPECTED TO REMAIN FARTHER TO THE SOUTH AND
WEST...WITH IWD SEEING THE GREATEST SHRA/TSRA POTENTIAL. VCTS
WAS INCLUDED AT IWD AS A START TO HINT AT THE EXPECTED TIMING OF THE
SHRA/TSRA.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 418 PM EDT MON AUG 26 2013
WINDS LESS THAN 20 KTS EXPECTED ACROSS LK SUPERIOR MUCH OF THIS
WEEK. THE ONLY EXCEPTION WOULD BE WHEN STRONGER THUNDERSTORMS ROLL
ACROSS THE WRN LAKE AND PRODUCE STRONGER GUSTS...AS HAS BEEN SEEN
THE LAST SEVERAL DAYS. OTHER THAN THOSE THUNDERSTORMS...GIVEN THE
WARM AND HUMID AIRMASS IN PLACE ALONG WITH ADDITIONAL MOISTURE FROM
SHOWERS AND THUNDERSTORMS...AREAS OF DENSE FOG WILL BE THE OTHER
MAIN CONCERN THROUGH MUCH OF THE WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
424 PM EDT MON AUG 26 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 418 PM EDT MON AUG 26 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE
CENTERED OVER MO/KS RESULTING IN ACYC FLOW FROM THE NRN PLAINS
THROUGH THE UPPER MS VALLEY INTO THE GREAT LAKES. WAA IN ADVANCE OF
AN UPSTREAM SHORTWAVE TROUGH MOVING INTO SW NORTH DAKOTA SUPPORTED
AN AREA OF LIGHT TO MODERATE RAIN WITH ONLY ISOLD TSRA. AT THE
SFC...THE CONVECTION THIS MORNING HELPED PUSH THE WEAK FRONTAL
BOUNDARY INTO NRN WI AND EXTENDED FROM NEAR HYR TO GRB. TEMPS TO THE
SOUTH OF THE FRONT HAVE AGAIN CLIMBED TO AROUND 90 WHILE MORE
MODERATE READINGS IN THE LOW TO MID 80S PREVAILED TO THE NORTH.
DEWPOINTS THROUGH THE REGION WERE NEAR 70F WITH 12Z OBSERVED AND
FCST SOUNDINGS SHOWING PWAT VALUES AROUND 2.0 INCHES(200 PCT OF
NORMAL).
EXPECT THAT AS THE ND SHRTWV MOVES TO THE EAST AND WAA INCREASES
THIS EVENING...EXPECT SHRA/TSRA TO DEVELOP AND QUICKLY IN INCREASE
IN COVERAGE BY LATE EVENING IN THE VCNTY OF THE SFC-800 MB FRONT
FROM CNTRL MN INTO NW WI. EVEN THOUGH THE MODELS HAVE TRENDED
FARTHER SOUTH WITH THE PCPN AND SHOW THE MOST FAVORABLE 310K
ISENTROPIC LIFT REMAINING SOUTH OF THE CWA...THERE IS STILL
CONSIDERABLE UNCERTAINTY ON THE LOCATION OF THE STRONGEST CONVECTION.
MOST OF THE HIGHER RES MODELS KEEP NEARLY ALL THE PCPN SOUTH OF
THE CWA WHILE THE GFS/ECMWF AND HIGH RES RAPID REFRESH BRING PCPN
THROUGH MAINLY THE SW HALF OF THE CWA. SO...THE HIGHER POPS/QPF WERE
SHIFTED TO THE SOUTH WITH LOCATIONS ALONG THE WI BORDER SEEING THE
GREATEST POTENTIAL FOR STRONG TSRA.
WITH MUCAPE VALUES INTO THE 1000-1500 J/KG RANGE AND EFFECTIVE SHEAR
TO AROUND 30 KT...THERE IS THE POTENTIAL FOR MULTICELL CLUSTERS THAT
COULD PRODUCE VERY HEAVY RAIN AND LCL WIND DAMAGE...SIMILAR TO LAST
NIGHT. FCST CORFIDI VECTORS SUGGEST THAT STORM ELEMENTS SHOULD KEEP
ENOUGH FORWARD MOTION TO LIMIT POTENTIAL FOR EXCESSIVE RAINFALL.
HOWEVER...ONE TO TWO INCHES AMOUNTS MAY AGAIN BE COMMON ALONG THE
PATH OF HEAVIER CLUSTERS. ANY LEFTOVER SHRA/TSRA TUE MORNING OVER
MAINLY THE S CNTRL CWA IS EXPECTED TO DIMINISH AND SAG OFF TO THE SE
BY EARLY TO MID AFTERNOON.
WITH 850 MB TEMPS REMAINING AROUND 18C...MAX TEMPS SHOULD ALSO BE
SIMILAR TO TODAY WITH HIGHS INTO THE LOW TO MID 80S WITH SLIGHTLY
COOLER READINGS ALONG THE GREAT LAKES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 429 AM EDT MON AUG 26 2013
AS HAS BEEN THE CASE OVER THE LAST COUPLE OF DAYS...MODELS REMAIN IN
GOOD AGREEMENT WITH THE LARGE SCALE PATTERN OF AN UPPER HIGH
SPINNING OVER KANSAS/MISSOURI THROUGH MUCH OF THIS WEEK BEFORE
GRADUALLY WEAKENING TOWARDS THE WEEKEND. WHERE THEY HAVE BEEN
STRUGGLING IS WITH THE SMALLER SCALE DISTURBANCES ROTATING AROUND
THE HIGH AND INFLUENCING THE UPPER GREAT LAKES REGION.
FORTUNATELY...MODELS HAVE COME INTO BETTER AGREEMENT WITH A
SHORTWAVE ASSOCIATED WITH THE REMNANTS OF TROPICAL STORM IVO IN THE
EASTERN PACIFIC ROTATING AROUND THE UPPER RIDGE AND INFLUENCING THE
AREA TONIGHT INTO TUESDAY. THIS SHORTWAVE WILL BE ROUNDING THROUGH
THE DAKOTAS AND NORTHERN MINNESOTA TONIGHT AND THEN ACROSS UPPER
MICHIGAN ON TUESDAY MORNING. IN ADDITION...THERE IS BETTER AGREEMENT
ON THE TRACK OF THE LOW AND ASSOCIATED WARM FRONT EXITING THE
DAKOTAS...WITH THE QPF FIELDS NOW ONLY HAVING A SPREAD OF A
150 MILES COMPARED TO 300 MILES BEFORE. THE CONSENSUS IS THE
PRECIPITATION FOCUSED MORE OVER NORTH CENTRAL MINNESOTA...UPPER
MICHIGAN AND NORTHERN WISCONSIN. WITH THE CONVECTION THAT WILL
LIKELY BE ONGOING ON THE STALLED BOUNDARY STRETCHING FROM NORTHERN
WISCONSIN EAST-NORTHEAST INTO NORTH CENTRAL MINNESOTA AND EASTERN
NORTH DAKOTA...THE QUESTION COMES ON IF THAT CONVECTION BEING SOUTH
OF THE AREA INITIALLY WILL BE ENOUGH TO KEEP THE CONVECTION
ASSOCIATED WITH THE SHORTWAVE SOUTH. THINK THE CONVECTION BEING
SOUTH IS A REASONABLE IDEA AT LEAST INITIALLY TONIGHT...BUT WITH THE
SHORTWAVE TRACKING FARTHER TO THE NORTH AND STORM MOTIONS AND
FORWARD PROP CORFIDI VECTORS FROM ANY STORMS IN MINNESOTA PUSHING
EAST...BELIEVE THAT AT LEAST THE SOUTH HALF OF THE CWA (INCLUDING
MOST OF UPPER MICHIGAN) WILL BE AFFECTED BY THE CONVECTION MOVING
THROUGH. MID-LEVEL MOISTURE TRANSPORT INCREASES CONFIDENCE
IN THAT IDEA...WITH IT SUPPORTING BOTH THE INITIAL CONVECTION
ALONG THE EXISTING BOUNDARY AND THEN REFOCUSING MORE OVER THE U.P.
TOWARDS TUESDAY MORNING WITH THE SHORTWAVE. OVERALL...KEPT THE
GENERAL IDEA FROM THE PREVIOUS SHIFT...BUT CONTINUED THE SLIGHT
SOUTHWARD TREND STARTED YESTERDAY TO THE HIGHEST POPS.
HEAVY RAIN WILL BE THE LARGEST THREAT TUESDAY MORNING...WITH MODELS
CONTINUING TO SHOW PWATS OF 200-250 PERCENT OF NORMAL AND FREEZING
LEVELS OF 14.5-15KFT. BUT SINCE 0-6KM SHEAR VALUES OF 35KTS WOULD
SUPPORT SOME ORGANIZATION...COULD SEE DAMAGING WINDS (AND LARGE HAIL
INITIALLY) IN THE STRONGER STORMS OR LINES THAT DEVELOP.
THE SHORTWAVE AND CONVECTION WILL DEPART FROM WEST TO EAST ON
TUESDAY AFTERNOON AND EARLY EVENING AND HAVE FOLLOWED THAT IDEA FOR
POPS. THEN...WITH THE WEAK LOW MOVING EAST AND A HIGH PRESSURE
RIDGE NOSING SOUTH FROM A HIGH CENTERED OVER HUDSON BAY...NORTHERLY
FLOW WILL DEVELOP OVER THE AREA TUESDAY NIGHT AND REMAIN INTO
WEDNESDAY MORNING. ASSUMING THAT THERE WILL BE FOG OVER LAKE
SUPERIOR AND THIS NORTHWESTERLY FLOW WILL PUSH IT SOUTH AND OVER
LOCATIONS NEAR LAKE SUPERIOR BY DAYBREAK WEDNESDAY. THIS WILL
LIKELY CONTINUE THROUGH THE MORNING HOURS ON WEDNESDAY...EITHER AS
FOG OR LOW STRATUS. ALTHOUGH THIS MOISTURE WILL BE VERY
SHALLOW...SOME OF THE MODELS ARE GIVING THE TELL TALE BLOTCHY 0.01
OF QPF USUALLY NOTED WITH THESE TYPES OF FOG EVENTS OVER THE GREAT
LAKES. FEEL LIKE WE/VE HAD A DECENT HANDLE ON THIS IDEA OVER THE
LAST SEVERAL SHIFTS...SO ONLY MADE MINOR TWEAKS TO THE GOING
FORECAST.
THE HIGH PRESSURE RIDGE WILL SLIDE ACROSS THE AREA ON WEDNESDAY
AFTERNOON/NIGHT AND THEN SHIFT SOUTHEAST ON THURSDAY. THIS SHOULD
GIVE THE AREA DRY...SLIGHTLY COOLER...AND LESS HUMID WEATHER.
COOLEST TEMPERATURES ON WEDNESDAY WILL BE NEAR LAKE SUPERIOR
(HIGHS IN THE MID 70S) WHERE THE CLOUDS/FOG WILL HANG ON LONGEST.
OVER THE SOUTH CENTRAL...LINGERING WARM AIR ALOFT AND MORE SUNSHINE
WILL PUSH TEMPS INTO AT LEAST THE MID 80S. HIGHS THURSDAY WILL BE A
TOUCH WARMER...ESPECIALLY NEAR THE GREAT LAKES AS SOUTHWESTERLY
FLOW BEGINS TO INCREASE WITH THE HIGH EXITING.
FOR THURSDAY AFTERNOON INTO THURSDAY NIGHT...MODELS CONTINUE TO
SHOW A SHORTWAVE ROUNDING THE UPPER RIDGE AND MOVING THROUGH THE
UPPER GREAT LAKES BUT STILL DIFFER SOMEWHAT ON THE LOCATION. WILL
HANDLE WITH SLIGHT CHANCE POPS FOR NOW OVER THE SOUTHWEST
HALF OF THE CWA...UNTIL THERE IS BETTER AGREEMENT ON PCPN CHANCES.
FROM FRIDAY NIGHT ON...THE SMALLER SCALE FEATURES DIFFER BUT THE
GENERAL IDEA OF THE UPPER RIDGE BREAKING DOWN SOME AND THE TROUGH
OVER THE PACIFIC NORTHWEST SLOWLY SHIFTING EAST WHILE EJECTING
ADDITIONAL SHORTWAVES IS CONSISTENT IN THE MODELS. THIS WILL PUT
THE AREA UNDER ADDITIONAL CHANCES FOR PRECIPITATION FOR THE LABOR
DAY WEEKEND. DUE TO THE LIMITED SKILL ON TIMING...WILL JUST GO WITH
SLIGHT AND CHANCE POPS AT THIS POINT. ALSO...TEMPERATURES SHOULD
REMAIN ABOVE NORMAL THIS WEEKEND...WITH 850MB TEMPS SOMEWHERE
BETWEEN 18-23C.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 143 PM EDT MON AUG 26 2013
A SFC TROUGH/VERY WEAK COLD FRONT THAT TRIGGERED SHRA/TSRA EARLIER
THIS MORNING HAS MOVED SOUTH INTO NORTHERN WISCONSIN. EXPECT MOSTLY
DRY/VFR CONDITIONS INTO THIS EVENING THEN LATER TONIGHT MORE
SHRA/TSRA COULD IMPACT THE REGION YET AGAIN. HOWEVER...THE BEST
CHANCE OF SHRA/TSRA IS EXPECTED TO REMAIN FARTHER TO THE SOUTH AND
WEST...WITH IWD SEEING THE GREATEST SHRA/TSRA POTENTIAL. VCTS
WAS INCLUDED AT IWD AS A START TO HINT AT THE EXPECTED TIMING OF THE
SHRA/TSRA.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 418 PM EDT MON AUG 26 2013
WINDS LESS THAN 20 KTS EXPECTED ACROSS LK SUPERIOR MUCH OF THIS
WEEK. THE ONLY EXCEPTION WOULD BE WHEN STRONGER THUNDERSTORMS ROLL
ACROSS THE WRN LAKE AND PRODUCE STRONGER GUSTS...AS HAS BEEN SEEN
THE LAST SEVERAL DAYS. OTHER THAN THOSE THUNDERSTORMS...GIVEN THE
WARM AND HUMID AIRMASS IN PLACE ALONG WITH ADDITIONAL MOISTURE FROM
SHOWERS AND THUNDERSTORMS...AREAS OF DENSE FOG WILL BE THE OTHER
MAIN CONCERN THROUGH MUCH OF THE WEEK.
&&
.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 GRAND RAPIDS MI
149 PM EDT MON AUG 26 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 344 AM EDT MON AUG 26 2013
WARM AND HUMID DAYS WILL CONTINUE TODAY AND TUESDAY. HOWEVER A COLD
FRONT WILL PASS THROUGH THE REGION TUESDAY NIGHT...BRINGING A GOOD
CHANCE FOR STORMS AS WELL AS LESS HUMID AIR INTO THE AREA BY
WEDNESDAY.
TEMPERATURES ARE EXPECTED TO REMAIN 85 TO 90 INTO THE WEEKEND
WITH ANOTHER CHANCE FOR RAIN BY FRIDAY NIGHT INTO SUNDAY.
&&
.UPDATE...
ISSUED AT 1115 AM EDT MON AUG 26 2013
THE CONVECTION THIS MORNING IS EXPECTED TO WEAKEN INTO THIS
AFTERNOON AS THE SHORTWAVE THAT HELPED CREATE IT MOVE EAST OVER
CENTRAL LOWER MICHIGAN RESULTING IN DPVA OVER OUR AREA. THE
OUTFLOW BOUNDARY IS MOVING INTO MORE STABLE AIR SO I DO NOT THINK
THERE WILL BE SIGNIFICANT REDEVELOPMENT SOUTH OF INTERSTATE 96
THIS AFTERNOON. SO I FEATURE DECREASING POPS DURING THE AFTERNOON
TO SHOW THE DECREASING THREAT FOR STORMS INTO THE LATE AFTERNOON.
UPDATE ISSUED AT 853 AM EDT MON AUG 26 2013
I UPDATED THE GRIDS AND ZONE FORECAST TO TRACK THE LINE OF
THUNDERSTORMS SOUTHEAST ACROSS THE CENTRAL CWA BASED ON A
COMBINATION OF THE TIMING TOOL AND THE HRRR RUC (10Z). THIS WOULD
BRING THE STORMS TO NEAR LANSING AROUND 1045 AM THIS MORNING. THE
LOW LEVEL JET SPEED MAX IS JUST IN FRONT OF THIS LINE OF STORMS.
IT WEAKENS AS THE DAY PROGRESSES AND SHIFTS SOUTHEAST (RAP 11Z).
BY NOON THE CORE IS ONLY 30 KNOTS AND OVER MONTCALM AND GRATIOT
COUNTIES SO THE STORMS SHOULD HAVE A HARD TIME GETTING TO MUCH
FARTHER SOUTH THAN THAT.
I WILL HAVE TO WATCH WHAT HAPPENS FOR THIS AFTERNOON AS THE
VERTICAL TOTALS SOUTH OF ROUTE 10 ARE NEAR 29C AND THE 850 TO 500
MB LAPSE RATE IS NEAR 8C. SEEMS MORE STORMS ARE POSSIBLE THIS
AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 344 AM EDT MON AUG 26 2013
SEVERAL CHALLENGES IN THE SHORT TERM. FIRST WILL BE JUST HOW HOT
THE REGION GETS. THIS WILL LARGELY DEPEND ON THE AMOUNT OF SUNSHINE
WE GET...OR IF THE DEBRIS CLOUDS WIN OUT. SECONDLY WILL BE THE
INCREASING CHANCES FOR SHOWERS AND STORMS AS THE UPPER RIDGE WEAKENS
AND DRIFTS SOUTH WITH TIME.
HAVE DECIDED TO HOLD FAIRLY CONSISTENT WITH THE TEMP FORECAST
DESPITE A LARGE AREA OF DEBRIS CLOUDS UPSTREAM EARLY THIS MORNING.
MID/HI CLOUDS WILL SPREAD IN FROM THE THUNDERSTORM CLUSTER THAT
WAS OVER THE NORTHERN GREAT LAKES. IT APPEARS THERE IS ENOUGH
RIDGING IN PLACE TO THIN THESE CLOUDS WITH TIME AND MAX TEMPS
AROUND 90 STILL LOOK OK FOR TODAY. EXPECT A SIMILAR SETUP INTO
TUESDAY...AND HAVE MAINTAINED MAX TEMPS AROUND 90 AGAIN. TUESDAY
SHOULD BE THE WARMEST DAY CONSIDERING DEW POINTS WILL BE
HIGHER...DRIVING HEAT INDEX READINGS INTO THE MID AND UPPER 90S.
TEMPS WILL ONLY BE A COUPLE DEGREES COOLER ON WED AS A FRONT
PASSES THROUGH...ALSO BRINGING SLIGHTLY LOWER DEW POINTS.
AS FOR SHOWERS AND STORMS...THE CENTER OF THE UPPER HIGH WILL BE
NEAR KANSAS CITY TODAY AND IT WILL SLOWLY SINK SOUTH THROUGH WED.
IT/S INFLUENCES WILL SLOWLY LOSE ITS GRIP ON THE GREAT LAKES...AND
THE RING OF CONVECTION AROUND THIS RIDGE SHOULD GRADUALLY EASE INTO
THE CWA THROUGH THE SHORT TERM. AT THE SURFACE THE MODELS ARE IN
GOOD AGREEMENT PUSHING A COLD FRONT THROUGH HERE TUESDAY NIGHT.
THE BEST JET DYNAMICS STAYS TO OUR NORTH AND WEST TODAY AND TONIGHT.
SO FEEL ANY SHOWERS AND STORMS THAT REACHES THE GRR CWA WILL BE IN A
WEAKENING STATE AS THEY RUN AWAY FROM THE BEST DYNAMICS AND INTO THE
RIDGE. HOWEVER A LOW LEVEL JET IS POISED TO PUSH IN AHEAD OF THE
COLD FRONT BY TUESDAY AFTERNOON INTO THE EVENING. THIS APPEARS TO
BE THE BEST CHANCE FOR PCPN AND HAVE RAISED POPS TO LIKELY ACROSS
MUCH OF THE CWA. SEVERE STORMS WILL BE POSSIBLE FROM ROUGHLY MID
AFTERNOON THROUGH ABOUT MIDNIGHT. DAMAGING WIND WILL BE THE MAIN
THREAT WILL SOME LARGE HAIL POSSIBLE.
THE FRONT SHOULD BE THROUGH THE CWA BY WED MORNING AND HAVE
MAINTAINED A DRY FORECAST. NOT MUCH COOLER BEHIND THE FRONT...WITH
HEAT INDEX READINGS ONLY RETREATING TO AROUND 90.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 344 AM EDT MON AUG 26 2013
MODELS ARE CONSISTENT IN SHOWING THE PLAINS RIDGE HANGING ON THROUGH
THE LONG TERM WITH NORTHWEST FLOW IN PLACE OVER THE GREAT LAKES.
500MB HEIGHTS WILL BE HIGH ENOUGH (580S DM/S) AND 850MB TEMPS WARM
ENOUGH (+16C TO +20C) THAT HIGH TEMPS WILL REMAIN IN THE MIDDLE 80S
TO AROUND 90.
MAIN ISSUE WILL BE TRYING TO TIME ANY PRECIPITATION INTO THE AREA AS
SHORTWAVE ENERGY SLIDES SOUTHEAST IN THE NORTHWEST UPPER FLOW.
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT LOOK DRY WITH HIGH PRESSURE
IN PLACE BEHIND WEDNESDAY/S FROPA. FRIDAY AND FRIDAY NIGHT...BOTH
THE GFS AND THE ECMWF ARE INSISTENT THAT A WARM FRONT WILL BE NEARBY
WITH PRECIPITATION IN THE AREA. NOT CONFIDENT IN THIS SCENARIO...SO
ONLY HAVE 20 PCT POPS IN THE FORECAST. KEPT THE FORECAST DRY
SATURDAY AND SATURDAY NIGHT WITH ANOTHER 20 PCT CHANCE FOR SHOWERS
AND STORMS ON SUNDAY. THE ECMWF AND GFS DIVERGE ON SURFACE FEATURES
FOR NEXT SUNDAY. OPTED TO FOLLOW THE GFS HERE AND HAVE A SMALL
CHANCE IN THE FORECAST AS ANOTHER WARM FRONT IS PROGD IN THE AREA.
OVERALL..THE LONG TERM PERIOD LOOKS TO REMAIN WARM WITH ABOVE NORMAL
TEMPERATURES. PRECIPITATION CHANCES ARE A TOUGH CALL...BUT IT
APPEARS SMALL CHANCES FOR SHOWERS AND STORMS EXIST BOTH FRIDAY AND
SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 148 PM EDT MON AUG 26 2013
BIGGEST CONCERN IN THE 18Z FCSTS IS CONVECTIVE TRENDS THROUGH THE
PERIOD. CONVECTION THAT TRIED TO MOVE SOUTH INTO THE AREA THIS
MORNING HAS NOW JUST ABOUT TOTALLY DISSIPATED AS OF 1730Z. THE
AREA HAS BEEN LEFT WITH THE MAINLY MID AND HIGH CLOUD COVER LEFT
OVER FROM IT.
THE MAJORITY OF THE MOST RECENT HIGH RESOLUTION MODELS INDICATE
CONVECTION TRYING TO REFORM ACROSS NE WISCONSIN AND TO NEAR THE
KLDM AREA AROUND 23-02Z TIME FRAME. NOT SURE IT WILL DEVELOP DUE
TO THE COOL AIR MASS LEFT BEHIND BY THIS MORNING/S STORMS. WE WILL
ACCOUNT FOR IT WITH A VCTS BEGINNING AROUND 03Z AT KMKG AND KGRR WITH
IT EXPECTED TO SLIDE SOUTH THEREAFTER THROUGH 07-08Z.
IT IS NOT OUT OF THE REALM OF POSSIBILITIES WE COULD HAVE STORMS
AT ANY TIME AT THE SITES AFTER THAT THROUGH THE NIGHT. HOWEVER THE
NEXT BEST CHC OF STORMS LOOKS TO COME AFTER 14Z TUE AS A STORM
COMPLEX ROLLS OUT OF WISCONSIN AND INTO LOWER MI. WE WILL HIT THIS
CHC WITH A VCTS ALSO. ANY STORMS COULD SEE CONDITIONS LOWER
LOCALLY INTO THE IFR CATEGORY.
&&
.MARINE...
ISSUED AT 344 AM EDT MON AUG 26 2013
SOUTHWEST FLOW WILL CONTINUE TO BRING SCA CONDITIONS TODAY. HOWEVER
AS THE FRONT APPROACHES WINDS WILL SLOWLY WEAKEN. FEEL CONDITIONS
WILL IMPROVE TOWARD EVENING...AND AS SUCH...MOVED UP THE ENDING OF
THE SCA.
ANOTHER PERIOD OF HIGHER WINDS AND WAVES WILL OCCUR BEHIND THE FRONT
FOR LATE TUESDAY NIGHT INTO WEDNESDAY WHEN ANOTHER SCA MAY BE NEEDED
WITH A NORTHERLY FLOW.
&&
.HYDROLOGY...
ISSUED AT 344 AM EDT MON AUG 26 2013
MOST AREAS SHOULD SEE BETWEEN A HALF INCH AND ONE INCH OF RAIN
THROUGH TUESDAY NIGHT. THE HIGHEST TOTALS SHOULD BE ACROSS THE
NORTHERN CWA. THIS HAS BEEN THE DRIER AREA...A SHOULD BE ABLE TO
HANDLE THIS AMOUNT OF RAIN. LOCALIZED POOR DRAINAGE FLOODING WILL BE
POSSIBLE IN PERSISTENT STORMS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT UNTIL 6 PM EDT THIS EVENING FOR MIZ037-
043-050-056-064-071.
LM...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...DUKE
AVIATION...NJJ
HYDROLOGY...JK
MARINE...JK
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1116 AM EDT MON AUG 26 2013
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 344 AM EDT MON AUG 26 2013
WARM AND HUMID DAYS WILL CONTINUE TODAY AND TUESDAY. HOWEVER A COLD
FRONT WILL PASS THROUGH THE REGION TUESDAY NIGHT...BRINGING A GOOD
CHANCE FOR STORMS AS WELL AS LESS HUMID AIR INTO THE AREA BY
WEDNESDAY.
TEMPERATURES ARE EXPECTED TO REMAIN 85 TO 90 INTO THE WEEKEND
WITH ANOTHER CHANCE FOR RAIN BY FRIDAY NIGHT INTO SUNDAY.
&&
.UPDATE...
ISSUED AT 1115 AM EDT MON AUG 26 2013
THE CONVECTION THIS MORNING IS EXPECTED TO WEAKEN INTO THIS
AFTERNOON AS THE SHORTWAVE THAT HELPED CREATE IT MOVE EAST OVER
CENTRAL LOWER MICHIGAN RESULTING IN DPVA OVER OUR AREA. THE
OUTFLOW BOUNDARY IS MOVING INTO MORE STABLE AIR SO I DO NOT THINK
THERE WILL BE SIGNIFICANT REDEVELOPMENT SOUTH OF INTERSTATE 96
THIS AFTERNOON. SO I FEATURE DECREASING POPS DURING THE AFTERNOON
TO SHOW THE DECREASING THREAT FOR STORMS INTO THE LATE AFTERNOON.
UPDATE ISSUED AT 853 AM EDT MON AUG 26 2013
I UPDATED THE GRIDS AND ZONE FORECAST TO TRACK THE LINE OF
THUNDERSTORMS SOUTHEAST ACROSS THE CENTRAL CWA BASED ON A
COMBINATION OF THE TIMING TOOL AND THE HRRR RUC (10Z). THIS WOULD
BRING THE STORMS TO NEAR LANSING AROUND 1045 AM THIS MORNING. THE
LOW LEVEL JET SPEED MAX IS JUST IN FRONT OF THIS LINE OF STORMS.
IT WEAKENS AS THE DAY PROGRESSES AND SHIFTS SOUTHEAST (RAP 11Z).
BY NOON THE CORE IS ONLY 30 KNOTS AND OVER MONTCALM AND GRATIOT
COUNTIES SO THE STORMS SHOULD HAVE A HARD TIME GETTING TO MUCH
FARTHER SOUTH THAN THAT.
I WILL HAVE TO WATCH WHAT HAPPENS FOR THIS AFTERNOON AS THE
VERTICAL TOTALS SOUTH OF ROUTE 10 ARE NEAR 29C AND THE 850 TO 500
MB LAPSE RATE IS NEAR 8C. SEEMS MORE STORMS ARE POSSIBLE THIS
AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 344 AM EDT MON AUG 26 2013
SEVERAL CHALLENGES IN THE SHORT TERM. FIRST WILL BE JUST HOW HOT
THE REGION GETS. THIS WILL LARGELY DEPEND ON THE AMOUNT OF SUNSHINE
WE GET...OR IF THE DEBRIS CLOUDS WIN OUT. SECONDLY WILL BE THE
INCREASING CHANCES FOR SHOWERS AND STORMS AS THE UPPER RIDGE WEAKENS
AND DRIFTS SOUTH WITH TIME.
HAVE DECIDED TO HOLD FAIRLY CONSISTENT WITH THE TEMP FORECAST
DESPITE A LARGE AREA OF DEBRIS CLOUDS UPSTREAM EARLY THIS MORNING.
MID/HI CLOUDS WILL SPREAD IN FROM THE THUNDERSTORM CLUSTER THAT
WAS OVER THE NORTHERN GREAT LAKES. IT APPEARS THERE IS ENOUGH
RIDGING IN PLACE TO THIN THESE CLOUDS WITH TIME AND MAX TEMPS
AROUND 90 STILL LOOK OK FOR TODAY. EXPECT A SIMILAR SETUP INTO
TUESDAY...AND HAVE MAINTAINED MAX TEMPS AROUND 90 AGAIN. TUESDAY
SHOULD BE THE WARMEST DAY CONSIDERING DEW POINTS WILL BE
HIGHER...DRIVING HEAT INDEX READINGS INTO THE MID AND UPPER 90S.
TEMPS WILL ONLY BE A COUPLE DEGREES COOLER ON WED AS A FRONT
PASSES THROUGH...ALSO BRINGING SLIGHTLY LOWER DEW POINTS.
AS FOR SHOWERS AND STORMS...THE CENTER OF THE UPPER HIGH WILL BE
NEAR KANSAS CITY TODAY AND IT WILL SLOWLY SINK SOUTH THROUGH WED.
IT/S INFLUENCES WILL SLOWLY LOSE ITS GRIP ON THE GREAT LAKES...AND
THE RING OF CONVECTION AROUND THIS RIDGE SHOULD GRADUALLY EASE INTO
THE CWA THROUGH THE SHORT TERM. AT THE SURFACE THE MODELS ARE IN
GOOD AGREEMENT PUSHING A COLD FRONT THROUGH HERE TUESDAY NIGHT.
THE BEST JET DYNAMICS STAYS TO OUR NORTH AND WEST TODAY AND TONIGHT.
SO FEEL ANY SHOWERS AND STORMS THAT REACHES THE GRR CWA WILL BE IN A
WEAKENING STATE AS THEY RUN AWAY FROM THE BEST DYNAMICS AND INTO THE
RIDGE. HOWEVER A LOW LEVEL JET IS POISED TO PUSH IN AHEAD OF THE
COLD FRONT BY TUESDAY AFTERNOON INTO THE EVENING. THIS APPEARS TO
BE THE BEST CHANCE FOR PCPN AND HAVE RAISED POPS TO LIKELY ACROSS
MUCH OF THE CWA. SEVERE STORMS WILL BE POSSIBLE FROM ROUGHLY MID
AFTERNOON THROUGH ABOUT MIDNIGHT. DAMAGING WIND WILL BE THE MAIN
THREAT WILL SOME LARGE HAIL POSSIBLE.
THE FRONT SHOULD BE THROUGH THE CWA BY WED MORNING AND HAVE
MAINTAINED A DRY FORECAST. NOT MUCH COOLER BEHIND THE FRONT...WITH
HEAT INDEX READINGS ONLY RETREATING TO AROUND 90.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 344 AM EDT MON AUG 26 2013
MODELS ARE CONSISTENT IN SHOWING THE PLAINS RIDGE HANGING ON THROUGH
THE LONG TERM WITH NORTHWEST FLOW IN PLACE OVER THE GREAT LAKES.
500MB HEIGHTS WILL BE HIGH ENOUGH (580S DM/S) AND 850MB TEMPS WARM
ENOUGH (+16C TO +20C) THAT HIGH TEMPS WILL REMAIN IN THE MIDDLE 80S
TO AROUND 90.
MAIN ISSUE WILL BE TRYING TO TIME ANY PRECIPITATION INTO THE AREA AS
SHORTWAVE ENERGY SLIDES SOUTHEAST IN THE NORTHWEST UPPER FLOW.
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT LOOK DRY WITH HIGH PRESSURE
IN PLACE BEHIND WEDNESDAY/S FROPA. FRIDAY AND FRIDAY NIGHT...BOTH
THE GFS AND THE ECMWF ARE INSISTENT THAT A WARM FRONT WILL BE NEARBY
WITH PRECIPITATION IN THE AREA. NOT CONFIDENT IN THIS SCENARIO...SO
ONLY HAVE 20 PCT POPS IN THE FORECAST. KEPT THE FORECAST DRY
SATURDAY AND SATURDAY NIGHT WITH ANOTHER 20 PCT CHANCE FOR SHOWERS
AND STORMS ON SUNDAY. THE ECMWF AND GFS DIVERGE ON SURFACE FEATURES
FOR NEXT SUNDAY. OPTED TO FOLLOW THE GFS HERE AND HAVE A SMALL
CHANCE IN THE FORECAST AS ANOTHER WARM FRONT IS PROGD IN THE AREA.
OVERALL..THE LONG TERM PERIOD LOOKS TO REMAIN WARM WITH ABOVE NORMAL
TEMPERATURES. PRECIPITATION CHANCES ARE A TOUGH CALL...BUT IT
APPEARS SMALL CHANCES FOR SHOWERS AND STORMS EXIST BOTH FRIDAY AND
SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 720 AM EDT MON AUG 26 2013
VFR WEATHER IS EXPECTED THIS MORNING...WITH AN INCREASING
SOUTHWEST WIND. BY LATE MORNING...SOUTHWEST WINDS OF 10-20 KNOTS
SHOULD BE COMMON. MID AND HIGH CLOUDS WILL CONTINUE TO DRIFT IN
FROM THE NORTH...BASES SHOULD BE ABOVE 12000FT.
STORMS TO THE NORTH THIS MORNING MAY EVENTUALLY MAKE THERE WAY
INTO THE NORTHERN TAF SITES THIS AFTERNOON. CONFIDENCE IN THIS
OCCURRING IS NOT HIGH THOUGH AND ONLY INCLUDED VICINITY THUNDER
WORDING FOR THIS AFTERNOON.
CEILINGS OF 5000-10000FT ARE EXPECTED TONIGHT WITH THE POTENTIAL
OF ADDITIONAL STORMS ROLLING IN LATE. STORMS WILL MOVE ACROSS
MINNESOTA AND WISCONSIN THIS EVENING AND MAY PUSH INTO THE TAF
SITES LATE TONIGHT. CONFIDENCE IN THE EVOLUTION REMAINS LOW AND
GIVEN ITS THEN END OF THE FORECAST PERIOD DID NOT INCLUDE THUNDER
FOR LATE TONIGHT YET.
&&
.MARINE...
ISSUED AT 344 AM EDT MON AUG 26 2013
SOUTHWEST FLOW WILL CONTINUE TO BRING SCA CONDITIONS TODAY. HOWEVER
AS THE FRONT APPROACHES WINDS WILL SLOWLY WEAKEN. FEEL CONDITIONS
WILL IMPROVE TOWARD EVENING...AND AS SUCH...MOVED UP THE ENDING OF
THE SCA.
ANOTHER PERIOD OF HIGHER WINDS AND WAVES WILL OCCUR BEHIND THE FRONT
FOR LATE TUESDAY NIGHT INTO WEDNESDAY WHEN ANOTHER SCA MAY BE NEEDED
WITH A NORTHERLY FLOW.
&&
.HYDROLOGY...
ISSUED AT 344 AM EDT MON AUG 26 2013
MOST AREAS SHOULD SEE BETWEEN A HALF INCH AND ONE INCH OF RAIN
THROUGH TUESDAY NIGHT. THE HIGHEST TOTALS SHOULD BE ACROSS THE
NORTHERN CWA. THIS HAS BEEN THE DRIER AREA...A SHOULD BE ABLE TO
HANDLE THIS AMOUNT OF RAIN. LOCALIZED POOR DRAINAGE FLOODING WILL BE
POSSIBLE IN PERSISTENT STORMS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT UNTIL 6 PM EDT THIS EVENING FOR MIZ037-
043-050-056-064-071.
LM...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...DUKE
AVIATION...DUKE
HYDROLOGY...JK
MARINE...JK
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
854 AM EDT MON AUG 26 2013
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 344 AM EDT MON AUG 26 2013
WARM AND HUMID DAYS WILL CONTINUE TODAY AND TUESDAY. HOWEVER A COLD
FRONT WILL PASS THROUGH THE REGION TUESDAY NIGHT...BRINGING A GOOD
CHANCE FOR STORMS AS WELL AS LESS HUMID AIR INTO THE AREA BY
WEDNESDAY.
TEMPERATURES ARE EXPECTED TO REMAIN 85 TO 90 INTO THE WEEKEND
WITH ANOTHER CHANCE FOR RAIN BY FRIDAY NIGHT INTO SUNDAY.
&&
.UPDATE...
ISSUED AT 853 AM EDT MON AUG 26 2013
I UPDATED THE GRIDS AND ZONE FORECAST TO TRACK THE LINE OF
THUNDERSTORMS SOUTHEAST ACROSS THE CENTRAL CWA BASED ON A
COMBINATION OF THE TIMING TOOL AND THE HRRR RUC (10Z). THIS WOULD
BRING THE STORMS TO NEAR LANSING AROUND 1045 AM THIS MORNING. THE
LOW LEVEL JET SPEED MAX IS JUST IN FRONT OF THIS LINE OF STORMS.
IT WEAKENS AS THE DAY PROGRESSES AND SHIFTS SOUTHEAST (RAP 11Z).
BY NOON THE CORE IS ONLY 30 KNOTS AND OVER MONTCALM AND GRATIOT
COUNTIES SO THE STORMS SHOULD HAVE A HARD TIME GETTING TO MUCH
FARTHER SOUTH THAN THAT.
I WILL HAVE TO WATCH WHAT HAPPENS FOR THIS AFTERNOON AS THE
VERTICAL TOTALS SOUTH OF ROUTE 10 ARE NEAR 29C AND THE 850 TO 500
MB LAPSE RATE IS NEAR 8C. SEEMS MORE STORMS ARE POSSIBLE THIS
AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 344 AM EDT MON AUG 26 2013
SEVERAL CHALLENGES IN THE SHORT TERM. FIRST WILL BE JUST HOW HOT
THE REGION GETS. THIS WILL LARGELY DEPEND ON THE AMOUNT OF SUNSHINE
WE GET...OR IF THE DEBRIS CLOUDS WIN OUT. SECONDLY WILL BE THE
INCREASING CHANCES FOR SHOWERS AND STORMS AS THE UPPER RIDGE WEAKENS
AND DRIFTS SOUTH WITH TIME.
HAVE DECIDED TO HOLD FAIRLY CONSISTENT WITH THE TEMP FORECAST
DESPITE A LARGE AREA OF DEBRIS CLOUDS UPSTREAM EARLY THIS MORNING.
MID/HI CLOUDS WILL SPREAD IN FROM THE THUNDERSTORM CLUSTER THAT
WAS OVER THE NORTHERN GREAT LAKES. IT APPEARS THERE IS ENOUGH
RIDGING IN PLACE TO THIN THESE CLOUDS WITH TIME AND MAX TEMPS
AROUND 90 STILL LOOK OK FOR TODAY. EXPECT A SIMILAR SETUP INTO
TUESDAY...AND HAVE MAINTAINED MAX TEMPS AROUND 90 AGAIN. TUESDAY
SHOULD BE THE WARMEST DAY CONSIDERING DEW POINTS WILL BE
HIGHER...DRIVING HEAT INDEX READINGS INTO THE MID AND UPPER 90S.
TEMPS WILL ONLY BE A COUPLE DEGREES COOLER ON WED AS A FRONT
PASSES THROUGH...ALSO BRINGING SLIGHTLY LOWER DEW POINTS.
AS FOR SHOWERS AND STORMS...THE CENTER OF THE UPPER HIGH WILL BE
NEAR KANSAS CITY TODAY AND IT WILL SLOWLY SINK SOUTH THROUGH WED.
IT/S INFLUENCES WILL SLOWLY LOSE ITS GRIP ON THE GREAT LAKES...AND
THE RING OF CONVECTION AROUND THIS RIDGE SHOULD GRADUALLY EASE INTO
THE CWA THROUGH THE SHORT TERM. AT THE SURFACE THE MODELS ARE IN
GOOD AGREEMENT PUSHING A COLD FRONT THROUGH HERE TUESDAY NIGHT.
THE BEST JET DYNAMICS STAYS TO OUR NORTH AND WEST TODAY AND TONIGHT.
SO FEEL ANY SHOWERS AND STORMS THAT REACHES THE GRR CWA WILL BE IN A
WEAKENING STATE AS THEY RUN AWAY FROM THE BEST DYNAMICS AND INTO THE
RIDGE. HOWEVER A LOW LEVEL JET IS POISED TO PUSH IN AHEAD OF THE
COLD FRONT BY TUESDAY AFTERNOON INTO THE EVENING. THIS APPEARS TO
BE THE BEST CHANCE FOR PCPN AND HAVE RAISED POPS TO LIKELY ACROSS
MUCH OF THE CWA. SEVERE STORMS WILL BE POSSIBLE FROM ROUGHLY MID
AFTERNOON THROUGH ABOUT MIDNIGHT. DAMAGING WIND WILL BE THE MAIN
THREAT WILL SOME LARGE HAIL POSSIBLE.
THE FRONT SHOULD BE THROUGH THE CWA BY WED MORNING AND HAVE
MAINTAINED A DRY FORECAST. NOT MUCH COOLER BEHIND THE FRONT...WITH
HEAT INDEX READINGS ONLY RETREATING TO AROUND 90.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 344 AM EDT MON AUG 26 2013
MODELS ARE CONSISTENT IN SHOWING THE PLAINS RIDGE HANGING ON THROUGH
THE LONG TERM WITH NORTHWEST FLOW IN PLACE OVER THE GREAT LAKES.
500MB HEIGHTS WILL BE HIGH ENOUGH (580S DM/S) AND 850MB TEMPS WARM
ENOUGH (+16C TO +20C) THAT HIGH TEMPS WILL REMAIN IN THE MIDDLE 80S
TO AROUND 90.
MAIN ISSUE WILL BE TRYING TO TIME ANY PRECIPITATION INTO THE AREA AS
SHORTWAVE ENERGY SLIDES SOUTHEAST IN THE NORTHWEST UPPER FLOW.
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT LOOK DRY WITH HIGH PRESSURE
IN PLACE BEHIND WEDNESDAY/S FROPA. FRIDAY AND FRIDAY NIGHT...BOTH
THE GFS AND THE ECMWF ARE INSISTENT THAT A WARM FRONT WILL BE NEARBY
WITH PRECIPITATION IN THE AREA. NOT CONFIDENT IN THIS SCENARIO...SO
ONLY HAVE 20 PCT POPS IN THE FORECAST. KEPT THE FORECAST DRY
SATURDAY AND SATURDAY NIGHT WITH ANOTHER 20 PCT CHANCE FOR SHOWERS
AND STORMS ON SUNDAY. THE ECMWF AND GFS DIVERGE ON SURFACE FEATURES
FOR NEXT SUNDAY. OPTED TO FOLLOW THE GFS HERE AND HAVE A SMALL
CHANCE IN THE FORECAST AS ANOTHER WARM FRONT IS PROGD IN THE AREA.
OVERALL..THE LONG TERM PERIOD LOOKS TO REMAIN WARM WITH ABOVE NORMAL
TEMPERATURES. PRECIPITATION CHANCES ARE A TOUGH CALL...BUT IT
APPEARS SMALL CHANCES FOR SHOWERS AND STORMS EXIST BOTH FRIDAY AND
SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 720 AM EDT MON AUG 26 2013
VFR WEATHER IS EXPECTED THIS MORNING...WITH AN INCREASING
SOUTHWEST WIND. BY LATE MORNING...SOUTHWEST WINDS OF 10-20 KNOTS
SHOULD BE COMMON. MID AND HIGH CLOUDS WILL CONTINUE TO DRIFT IN
FROM THE NORTH...BASES SHOULD BE ABOVE 12000FT.
STORMS TO THE NORTH THIS MORNING MAY EVENTUALLY MAKE THERE WAY
INTO THE NORTHERN TAF SITES THIS AFTERNOON. CONFIDENCE IN THIS
OCCURRING IS NOT HIGH THOUGH AND ONLY INCLUDED VICINITY THUNDER
WORDING FOR THIS AFTERNOON.
CEILINGS OF 5000-10000FT ARE EXPECTED TONIGHT WITH THE POTENTIAL
OF ADDITIONAL STORMS ROLLING IN LATE. STORMS WILL MOVE ACROSS
MINNESOTA AND WISCONSIN THIS EVENING AND MAY PUSH INTO THE TAF
SITES LATE TONIGHT. CONFIDENCE IN THE EVOLUTION REMAINS LOW AND
GIVEN ITS THEN END OF THE FORECAST PERIOD DID NOT INCLUDE THUNDER
FOR LATE TONIGHT YET.
&&
.MARINE...
ISSUED AT 344 AM EDT MON AUG 26 2013
SOUTHWEST FLOW WILL CONTINUE TO BRING SCA CONDITIONS TODAY. HOWEVER
AS THE FRONT APPROACHES WINDS WILL SLOWLY WEAKEN. FEEL CONDITIONS
WILL IMPROVE TOWARD EVENING...AND AS SUCH...MOVED UP THE ENDING OF
THE SCA.
ANOTHER PERIOD OF HIGHER WINDS AND WAVES WILL OCCUR BEHIND THE FRONT
FOR LATE TUESDAY NIGHT INTO WEDNESDAY WHEN ANOTHER SCA MAY BE NEEDED
WITH A NORTHERLY FLOW.
&&
.HYDROLOGY...
ISSUED AT 344 AM EDT MON AUG 26 2013
MOST AREAS SHOULD SEE BETWEEN A HALF INCH AND ONE INCH OF RAIN
THROUGH TUESDAY NIGHT. THE HIGHEST TOTALS SHOULD BE ACROSS THE
NORTHERN CWA. THIS HAS BEEN THE DRIER AREA...A SHOULD BE ABLE TO
HANDLE THIS AMOUNT OF RAIN. LOCALIZED POOR DRAINAGE FLOODING WILL BE
POSSIBLE IN PERSISTENT STORMS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT UNTIL 6 PM EDT THIS EVENING FOR MIZ037-
043-050-056-064-071.
LM...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...DUKE
AVIATION...DUKE
HYDROLOGY...JK
MARINE...JK
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
1220 AM CDT MON AUG 26 2013
.SYNOPSIS...
ISSUED AT 359 PM CDT SUN AUG 25 2013
NOT MUCH HAS CHANGED IN THE UPPER LEVELS IN THE LAST 24 HRS...WITH A
598 DM HIGH CENTERED OVER MISSOURI THAT IS STILL FLANKED BY TROUGHS
ON EITHER COAST OF NOAM. ACROSS THE ROCKIES...WATER VAPOR IMAGERY IS
SHOWING A TROPICAL MOISTURE PLUME FROM THE REMNANTS OF AN ERN
PACIFIC TROPICAL SYSTEM CURRENTLY OVER THE BAJA PENINSULA THAT IS
NOW WORKING ITS WAY AROUND THE WRN PERIPHERY OF THE MISSOURI HIGHS
AND ALREADY MOVING UP INTO WYOMING...LIKELY REACHING THE UPPER MS
VALLEY MONDAY.
AT THE SFC A TROUGH OF LOW PRESSURE WAS SITUATED FROM CENTRAL SODAK
NE TO NEAR INL. STRONG PRESSURE GRADIENT IS STILL IN PLACE...WITH
BREEZY SOUTHWEST WINDS CONTINUING. WITH TEMPS IN THE LOW TO MID 90S
AND DEWPS IN THE LOW TO MID 70S...STARTING TO SEE HEAT INDICES CLIMB
TO OVER 100 DEGREES...WITH VALUES OF MLCAPE UP SAFELY IN THE HEALTHY
RANGE BETWEEN 3500 AND 6000 J/KG.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 359 PM CDT SUN AUG 25 2013
AS CAN BE IMAGINED...WITH A CAPPED...WEAKLY FORCED...HIGH CAPE
ENVIRONMENT...CONFIDENCE IS STILL QUITE LOW ON WHERE/IF CONVECTION
WILL FIRE LATER THIS EVENING. ONE THING IS FOR SURE...PRESENCE OF
ENOUGH INSTABILITY IS NOT AN ISSUE!
WHEN LOOKING AT THE SPC MESO ANALYSIS AND SATELLITE ALONG
WITH A FEW INSTABILITY/MOISTURE TRANSPORT FIELDS FROM THE
DETERMINISTIC MODELS YOU CAN GET A SENSE OF HOW THINGS SHOULD TRY TO
UNFOLD THIS EVENING. FROM THE MESO ANALYSIS SIDE OF THINGS...THERE
IS A GRADIENT IN THE MLCAPE FIELD ACROSS CENTRAL MN...WHICH IS
COINCIDENT WITH THE NRN EDGE OF THE STEEPER MID LEVEL LAPSE RATES
ASSOCIATED WITH AN EML AND STRONGER CAPPING. JUST NORTH OF THE
MLCAPE GRADIENT...THE 20Z ANALYSIS SHOWS H7 DEWPOINTS BETTER THAN
10C ACROSS THE SRN END OF THE DLH/FGF FORECAST AREAS. WITHIN THIS
ZONE OF HIGHER MOISTURE AT H7 MOISTURE...A SHALLOW CU FIELD HAS
DEVELOPED BENEATH A FEW BITS OF ACCUS THAT STRETCH FROM AROUND
FERGUS FALLS OVER TOWARD DULUTH. BEST GUESS RIGHT NOW IS THAT IF
STORMS ARE TO DEVELOP...IT WILL BE WITHIN THIS ZONE...LIKELY CLOSER
TO 00Z.
IN ADDITION...MODELS SHOW THE LLJ AND ASSOCIATED MOISTURE ADVECTION
VEERING SOME AND SAGGING SOUTH THROUGH THE NIGHT. THE AREA OF CLOUDS
REFERENCED ABOVE ALSO SITS ON THE NRN EDGE OF THE MAIN MOISTURE
TRANSPORT PLUME AT H85...WHICH MOST GUIDANCE SHOW COMING DOWN TO
ABOUT I-94 OVERNIGHT. IF SOMETHING CAN GET GOING...THE PRESENCE OF
THE LLJ SHOULD KEEP THE ACTIVITY GOING THROUGH MUCH OF THE NIGHT.
WITH THE RAP AND MOST OTHER MODELS SHOWING THE STRONGEST MOISTURE
TRANSPORT IN THE H85-H7 LAYER RESIDING OVER ERN MN/WRN
WI...CONTINUED TO ADVERTISE LIKELY POPS IN ERN AREAS...THAT TAIL OFF
TO LOW CHANCE POPS IN THE WEST FOR TONIGHT.
FROM THE SEVERE END OF THINGS...AN ENVIRONMENT ASSOCIATED WITH HIGH
MOISTURE CONTENT /PWATS CURRENT NEAR 2 INCHES/...DEEP MELTING
LAYERS...AND WEAK SHEAR MEANS LARGE HAIL WILL BE TOUGH TO COME BY.
HOWEVER...VALUES OF DCAPE UP AROUND 1500 J/KG INDICATES THE WIND
POTENTIAL IS CERTAINLY STILL THERE IF WE CAN GET ANY DEEP MOIST
CONVECTION GOING.
WHAT HAPPENS TONIGHT WILL GO A LONG WAY IN DETERMINING WHERE ANY
POTENTIAL CONVECTION CAN FIRE UP MONDAY AFTERNOON. THE QUESTION FOR
TOMORROW IS FAR SOUTH CAN THE BOUNDARY SLOWLY HEADING FOR CENTRAL MN
MAKE IT TONIGHT. IF WE DO SEE A GOOD AMOUNT OF CONVECTION
OVERNIGHT...THEN THERE IS A GOOD CHANCE THAT THE BOUNDARY CAN MAKE
IT DOWN TO ABOUT I-94. IF WE DO NOT SEE MUCH CONVECTION
TONIGHT...THEN IN ALL LIKELIHOOD...THE BOUNDARY WILL REMAIN NORTH OF
THE MPX AREA...WITH ANOTHER DAY OF CAPED SUNNY SKIES ENSUING. THE
NAM/SREF WOULD SUPPORT THE SRN IDEA...WHILE THE GFS/ECMWF/GEM GO
NORTH. FOR NOW WENT WITH CHANCE POPS AFTER 21Z FOR AREAS NORTH OF
I-94. FROM THE SEVERE PERSPECTIVE...ABOUT THE ONLY THING DIFFERENT
ABOUT MONDAY COMPARED TO TODAY IS THAT THE BELT OF STRONGER
WESTERLIES WILL HAVE SAGGED SOUTH A BIT MORE...INCREASING THE AMOUNT
OF DEEP LAYER SHEAR...WHICH WILL MAKE THE RISK OF LARGE HAIL A BIT
HIGHER OWING TO THE CHANCE OF GETTING AT LEAST WEAK SUPERCELL
STRUCTURES GOING.
LAST STOP IS WITH TEMPERATURES. OVERNIGHT...EXPECT CENTRAL MN TO
COOL A FEW DEGREES MORE THAN THEY DID LAST NIGHT AS THE PRESSURE
GRADIENT WEAKENS...ALLOWING FOR SOME RADIATIONAL COOLING TONIGHT.
STILL...WITH DEWPS AROUND 70...MOST PLACES SHOULD STILL STAY ABOVE
THAT MARK. FOR THE TWIN CITIES AND PLACES FARTHER SOUTH/EAST...WINDS
WILL REMAIN IN PLACE /THOUGH NOT AS STRONG AS LAST NIGHT/...WHICH
WILL KEEP SOME FORM OF MIXING GOING AND ONCE AGAIN MAKE IT A
STRUGGLE FOR A LOT OF PLACES TO DROP BELOW 80 WITHOUT THE HELP OF
RAIN.
FOR HIGHS TOMORROW...925-850 MB TEMPS ACTUALLY INCREASE A DEGREE OR
TWO AS COMPARED TO TODAY...WHICH WOULD THEORETICALLY MEAN WE COULD
GET A DEGREE OR TWO WARMER. HOWEVER...THERE IS THE POTENTIAL FOR A
BIG BUST WITH HIGHS TOMORROW DEPENDING ON WHAT HAPPENS WITH STORMS
TONIGHT. IF WE DO END UP SEEING FAIRLY WIDESPREAD AND ROBUST
CONVECTION OVERNIGHT...THIS WOULD LIKELY LEAVE BEHIND PLENTY OF
DEBRIS COLD COVER...PUTTING A DAMPER ON TEMPERATURES. THE HIRES NMM
EAST DOES EXACTLY THAT WITH CONVECTION OVERNIGHT. THE RESULTING
CLOUD COVER IT GENERATED FOR THE NEXT DAY RESULTED IN IT ONLY
GENERATING HIGHS IN THE MID/UPPER 80S. AT THE OTHER END OF THE
SCALE...A NIGHT OF LITTLE CONVECTION WILL RESULT IN ANOTHER DAY OF
LOTS OF SUN. IN THAT CASE...THEN HIGHS TOMORROW WOULD BE A DEGREE OR
TWO WARMER THAN TODAY...WITH HIGHS IN THE MID/UPPER 90S AND A FEW
100 DEGREE READINGS NOT OUT OF THE QUESTION IN WRN MN. AT ANY
RATE...DID NOT SEE ANYTHING GLARING CHANGE WITH THE TEMP FORECAST
TODAY THAT REQUIRED ANY CHANGES IN THE GOING HEAT HEADLINES.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 359 PM CDT SUN AUG 25 2013
LONG TERM TRENDS CONTINUE TO SHOW HOT AND HUMID CONDITIONS WILL
CONTINUE THROUGH AT LEAST TUESDAY. LOCATION OF FRONTAL BOUNDARY
MONDAY NIGHT WILL DETERMINE TO WHAT EXTENT/LOCATION CONVECTIVE ACTIVITY
WILL DEVELOP OVER THE CWA. VARIOUS DETERMINISTIC MODELS SHOW THIS
BOUNDARY LIFTING SLOWLY BACK NORTH MONDAY NIGHT AND INTO TUESDAY
AS WEAK COOL FRONT/SURFACE LOW MOVES THROUGH THE AREA. WILL
CONTINUE THE CHANCE POPS OVER THE NORTHEAST THIRD OF THE AREA FOR
TUESDAY...WHICH SHOULD EXIT THE CWA BY TUESDAY EVENING. EXPECT
TEMPERATURES TO RANGE IN THE MID/SOME UPPER 90S AND DEWPOINTS
POOLING AHEAD OF BOUNDARY INTO THE LOWER 70S. HEAT INDEX VALUES
WILL RANGE 100F TO 105F WITH THE CURRENT HEAT ADVISORY/WARNING
STILL LOOKING GOOD CONTINUING THROUGH TUESDAY.
SOME COOLING BEHIND THE FRONT LINGERING INTO FRIDAY...MAINLY OVER
THE EASTERN PORTION OF THE CWA. RIDGING ALOFT DEVELOPS THEREAFTER
WITH SURFACE FRONT MEANDERING OVER CENTRAL MINNESOTA AGAIN INTO
THE WEEKEND. THE 12Z ECMWF IS SLOWER BUILDING THE UPPER RIDGE TO
THE EAST...WITH THE MAIN SURGE COMING NEXT SUNDAY. THE GFS BUILDS
IN NORTH BY SATURDAY. WILL GO ALONG WITH PRESENT TREND OF BRINGING
THE 90S BACK INTO THE AREA FOR SATURDAY AND SUNDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1213 AM CDT MON AUG 26 2013
ALL THUNDERSTORM ACTIVITY HAS BEEN CONFINED TO NORTHEAST MN...LAKE
SUPERIOR...AND NOW THE U.P. OF MICHIGAN. THE ATMOSPHERE IS TOO
CAPPED FOR MUCH DEVELOPMENT THIS FAR SOUTH SO REMOVED TS MENTION
AT ALL TAF SITES. COULD STILL SEE ISOLATED CELLS DEVELOP
OVERNIGHT ACROSS ERN MN AND WRN WI...BUT THE PROBABILITY OF ANY
IN THE VICINITY OF TAF SITES IS QUITE LOW.
KMSP...VFR CONDITIONS EXPECTED. HIGH CLOUDS WILL STREAM
PERIODICALLY OVERHEAD THROUGH MONDAY.
/OUTLOOK FOR KMSP/
TUE...VFR. WIND SW 5-10 KT...BECOMING NW IN AFTERNOON.
WED...VFR. WIND LIGHT/VARIABLE.
THU...VFR. ISOLD SHRA/TS POSSIBLE. WIND LIGHT/VARIABLE.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...EXCESSIVE HEAT WARNING UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR
MNZ054>070-073>078-082>085-091>093.
HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR MNZ041>045-
047>053.
WI...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR WIZ014>016-
023>028.
&&
$$
SYNOPSIS...MPG
SHORT TERM...MPG
LONG TERM...DWE
AVIATION...BORGHOFF
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
915 PM MDT TUE AUG 27 2013
.UPDATE...
UPDATED ZFP JUST SENT. TRIMMED POPS FOR REMAINDER OF TONIGHT.
CONVECTION CONTINUES TO WANE AND DESPITE THE INCREASE IN
PW...DEEP EASTERLY WINDS ALF ON EVENING RAOBS INDICATED A STABLE
AIRMASS. LATEST RUC13 INDICATES MINIMAL QPF AS WELL FOR THE OVERNIGHT.
&&
.PREV DISCUSSION...539 PM MDT TUE AUG 27 2013...
.AVIATION...
00Z TAF CYCLE
ISOLD SHRA AND TSRA WILL CONTINUE THROUGH THE EVENING HOURS.
STORMS WILL LARGELY DIMINISH BY 04-06Z. BRIEF HEAVY RAIN WILL BE
THE MAIN THREAT WITH ANY REMAINING STORMS. OVERNIGHT...COULD SEE
SOME MVFR CIGS SE OF A LINE FROM KROW TO KCVS. IF THIS OCCURS...IT
WOULD MAINLY BE BETWEEN 10Z AND 14Z. ISOLD TS ACTIVITY WILL RETURN
WED AFTN...WITH PERHAPS SLIGHTLY MORE ACTIVITY ACROSS THE SW MTNS.
34
&&
.PREV DISCUSSION...300 PM MDT TUE AUG 27 2013...
HAVE MADE SOME FAIRLY SUBSTANTIAL CHANGES TO THE MEDIUM AND EXTENDED
RANGE FORECAST IN FAVOR OF A MUCH WETTER PATTERN. THE LATEST CIRA
BLENDED TPW IMAGERY SHOWS A DEEP POOL OF 150 PCT OF NORMAL MOISTURE
ENTRENCHED OVER BAJA MEXICO AND NEARLY ALL OF TX. MOISTURE TRANSPORT
WILL BE IMPRESSIVE AS WE PROGRESS THRU THE END OF THIS WEEK INTO THE
LABOR DAY HOLIDAY AS A LARGE INVERTED TROUGH SHIFTS NW OVER NM.
CURRENTLY THERE IS A RELATIVELY STABLE AND DRY AIRMASS IN PLACE OVER
CENTRAL AND EASTERN NM...LEADING TO ONLY ISOLATED STORM COVERAGE AT
BEST FOR FAR WESTERN NM. THERE WILL BE LITTLE CHANGE TO THIS THEME
THRU WEDNESDAY AS INDICATED BY THE BULK OF OPERATIONAL GUIDANCE...
INCLUDING HPC PROBABILISTIC QPF AND MODEL ENSEMBLES. AN UPTICK IN
COVERAGE IS HOWEVER EXPECTED WEDNESDAY FOR THE GILA REGION TO THE
SOUTH CENTRAL MTS.
THE AFOREMENTIONED MOISTURE SURGE ADVECTS QUICKLY NW ACROSS NM
STARTING THURSDAY. PWAT VALUES ARE PROGGED TO AVERAGE 1 TO 1.2
INCHES WHICH WILL APPROACH 150 PCT OF NORMAL. INSTABILITY IN ASSCN
WITH THE WELL DEFINED INVERTED TROUGH WILL RESULT IN AT LEAST SCT
COVERAGE FROM THE GILA REGION NORTH ACROSS THE CONT DVD INTO THE
NORTHERN MTS. STEERING FLOW WILL BE WEAKER WITHIN THE TROUGH AXIS
THUS LCL HEAVY RAIN IS POSSIBLE. THE GFS AND ECMWF BOTH INDICATE
MOIST INSTABILITY WITH THIS WAVE WILL BECOME TRAPPED UNDER AN
UPPER RIDGE SHIFTING BACK SOUTH OVER THE REGION FRIDAY. THIS WILL
WEAKEN STEERING FLOW FURTHER ELEVATING THE POTENTIAL FOR HEAVY RAIN.
VERY LITTLE CHANGE IS ADVERTISED BY THE GFS WITHIN A WELL DEFINED
STRONGLY UNSTABLE MOISTURE AXIS CENTERED OVER THE CONT DVD BOTH
SATURDAY AND SUNDAY. THE POTENTIAL FOR LCL HEAVY RAIN WILL BE THE
GREATEST FOR THIS PERIOD. THE 12Z ECMWF HAS TRENDED MUCH DRIER WITH
A SPRAWLING UPPER RIDGE OVER THE DESERT SW. SINCE THIS IS A BIG
CHANGE FROM PREVIOUS TRENDS HAVE PUSHED THAT ASIDE FOR NOW AND
RAISED POPS THRU THE HOLIDAY WEEKEND. A SPECIAL WX STATEMENT MAY BE
ON THE HORIZON WITH POTENTIAL FOR A FLASH FLOOD WATCH IF TRENDS
CONTINUE TO INDICATE HEAVY RAIN. THIS SHOULD SERVE TO RAISE PUBLIC
AWARENESS OF A RETURN TO A STRONGER MONSOON PATTERN AS A SIGNIFICANT
NUMBER OF OUTDOOR LABOR DAY ACTIVITIES WILL BE ONGOING.
THE GFS INTRODUCES ANOTHER WELL DEFINED MOIST EASTERLY WAVE FOR
MONDAY INTO THE MIDDLE OF NEXT WEEK WITH A FOCUS OVER NORTHERN/
WESTERN NM. THE HPC 8-14 DAY OUTLOOK INDICATES A GOOD CHANCE FOR
ABOVE NORMAL PRECIPITATION IN THIS AREA...SO WILL CONTINUE THE
TREND OF RAISING POPS.
GUYER
&&
.FIRE WEATHER...
A STRONG UPPER LEVEL HIGH PRESSURE SYSTEM CENTERED OVER KANSAS CITY
THIS AFTERNOON WILL WEAKEN SOME AND GRADUALLY SHIFT ITS CENTER
WESTWARD OVER SOUTHERN CO BY THURSDAY. MEANWHILE AN EASTERLY WAVE
TRACKING SLOWLY NORTHWESTWARD ACROSS NORTHERN MEXICO WILL SPREAD
RICHER MOISTURE INTO SOUTHWEST PARTS OF THE FORECAST AREA WEDNESDAY.
A PORTION OF THIS WAVES ENERGY IS PROGGED TO LIFT NORTHWARD THROUGH
AZ THURSDAY AND FRIDAY. THIS SHOULD FUNNEL BETTER MONSOON MOISTURE
ACROSS MORE OF WESTERN NM AND TO A LESSER EXTENT CENTRAL PARTS OF
THE STATE WITH SCATTERED TO NUMEROUS THUNDERSTORMS MAINLY ALONG AND
WEST OF THE CENTRAL MOUNTAIN CHAIN BOTH DAYS. SUBSIDENCE CLOSER TO
THE CENTER OF THE HIGH PRESSURE SYSTEM SHOULD KEEP THE PLAINS ON THE
DRIER SIDE THROUGH THE END OF THE WORK WEEK WITH GRADUALLY WARMING
HIGH TEMPERATURES. THURSDAY AND FRIDAY...HIGHS ON THE PLAINS SHOULD
VARY FROM 6 TO 12 DEGREES ABOVE NORMAL WHILE WESTERN READINGS VARY
FROM NEAR NORMAL TO AROUND 3 DEGREES BELOW NORMAL.
OVER THE WEEKEND THE UPPER LEVEL HIGH PRESSURE SYSTEM WILL WEAKEN
SIGNIFICANTLY AND BROADEN OVER CO AND NM ALLOWING A RICH MONSOON
MOISTURE PLUME TO SPREAD UNDERNEATH THE RIDGE AND MORE SQUARELY OVER
NEW MEXICO. WITH PWAT VALUES AROUND 1 TO 1.5 INCHES ACROSS MUCH OF
WESTERN AND CENTRAL PARTS OF THE FORECAST AREA...THUNDERSTORMS WILL
BE CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL WITH A THREAT OF
FLASH FLOODING THURSDAY THROUGH SUNDAY. STORM MOTIONS WILL ALSO
SLOW TO A CRAWL AS THE WEAKENING DOME OF HIGH PRESSURE SPREADS OVER
THE REGION...ADDING TO THE FLASH FLOOD THREAT. THE PLAINS WILL ALSO
HAVE A CHANCE FOR WETTING PRECIP OVER THE WEEKEND...BUT HIGHER
PROBABILITIES SHOULD FAVOR CENTRAL AND WESTERN AREAS.
THE GFS AND ECMWF HAVE FAIR AGREEMENT THAT THE UPPER HIGH WILL
SLOWLY RESTRENGTHEN AND RECENTER NEAR KS/OK EARLY IN THE COMING WORK
WEEK. THIS WOULD ALLOW A LITTLE DRIER AIR TO FUNNEL INTO EASTERN
AREAS AND TIGHTEN THE FOCUS OF THE MONSOON MOISTURE PLUME MORE ALONG
THE CONTINENTAL DIVIDE. THIS WOULD ALSO ALLOW EASTERN HIGH
TEMPERATURES TO WARM...AFTER SOME POTENTIALLY COOLER READINGS
AREAWIDE OVER THE WEEKEND.
RELATIVE HUMIDITIES SHOULD REMAIN ABOVE CRITICAL THRESHOLDS
WEDNESDAY THROUGH MONDAY...WITH GOOD TO EXCELLENT OVERNIGHT
RECOVERIES. VENT RATES WILL GENERALLY BE GOOD OR BETTER...EXCEPT FOR
POCKETS OF POOR DISPERSION ASSOCIATED WITH PERIODS OF GREATER
THUNDERSTORM COVERAGE ACROSS CENTRAL AND WESTERN AREAS.
44
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
129 AM EDT MON AUG 26 2013
.SYNOPSIS...
AN APPROACHING FRONTAL SYSTEM WILL BRING SCATTERED SHOWERS AND
THUNDERSTORMS LATE TONIGHT AND MONDAY. DRY WEATHER IS FORECAST FOR
TUESDAY...BUT MORE SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE
TUESDAY NIGHT AND WEDNESDAY AS ANOTHER COLD FRONT MOVES THROUGH
THE REGION. AFTER THIS FRONT PASSES BY...FAIR WEATHER IS EXPECTED
FOR THURSDAY AND FRIDAY.
&&
.NEAR TERM /THROUGH TODAY/...
11 PM UPDATE...
EARLIER FORECASTER CAPTURED THE TIMING OF AN AREA OF RAIN AND
THUNDER QUITE WELL THAT IS NOW CROSSING LAKE ONTARIO. MAIN
ADJUSTMENT WAS TO SHIFT AXIS A BIT FARTHER WEST BASED ON RADAR THAN
WHAT THE HRRR AND NAM 12 IS SHOWING NOW. IN ADDITION INCREASED
POPS TO CAT GIVEN RADAR TRENDS AND INCREASED CONFIDENCE OF A 2 TO
4 HOUR WINDOW OF STEADY RAIN OVERNIGHT. STILL NOT OVERLY CONFIDENT
ON HOW FAR SOUTH IT MAKES IT TOWARD NORTHERN PA BECAUSE WE ARE
QUITE DRY...BUT CNY...FINGER LAKES...AND SOUTHERN TIER SEEM A SAFE
BET FOR NOW. AS THIS MCS SHIFTS SOUTHEAST AND DIES DOWN EARLY
MONDAY MORNING...WE MAY SEE A BREAK LATER MONDAY MORNING INTO THE
EARLY AFTERNOON. ON THE EDGE OF TONIGHT`S CONVECTION HOWEVER A NEW
AREA IS EXPECTED TO DEVELOP AGAIN MONDAY AFTERNOON/EVENING. SIGNS
STILL POINT TO THE POTENTIAL FOR LOCALLY HEAVY RAIN IN THE
NORTHWEST MOIST FLOW. THE PREVIOUS AFD IS BELOW...
UPDATED THE NEAR TEAM TO BRING POPS IN ERLYR FROM THE MCS
THAT IS MOVING ACRS ONT AND QUE AND THE NERN GREAT LAKES. THE HRRR
HAS BEEN SHOWING THAT THIS PRECIP WILL GET INTO NC AND EC NY
BETWEEN 1Z AND 6Z WITH THE RAP NOW SPEEDING THE ARRIVAL UP TOO
OVER THE OTHER MODELS. SINCE THESE ARE RAPID UPDATE CYCLE MODELS
AND THE RADAR TRENDS ARE CLSR TO THESE MODELS I NOW BRING IN
PRECIP MUCH ERLYR IN LINE WITH KBUF/S RECENT UPDATE. OTHERWISE...NO
OTHER CHANGES THRU MONDAY.
PREVIOUS DSCN BELOW...
VISIBLE SATL IMAGERY SHOWS SCT CUMULUS FORMING WITH INSOLATION.
SOME CIRRUS FROM AN UPSTREAM MCS OVER NRN AND CNTRL ONTARIO AND
THE UPPER LAKES WILL STREAM SOUTHEASTWARD FOR THE REST OF THE
AFTERNOON....THUS SKIES WILL BE PS TO MS. CANADIAN RADAR LOOP
SHOWS AN MCS WITH SHOWERS AND THUNDERSTORMS TRACKING SEWRD ACRS
GEORGIAN BAY AND TWD SERN ONTARIO INTO WRN QUEBEC. CONVECTION
ALLOWING MESOSCALE MODELS ...WRF-NMM, WRF-ARW AND HRRR ALL SHOW
THE SRN EDGE OF THE PRECIPITATION SHIELD WITH THIS MCS SKIRTING
ACRS NRN AND ERN NY TONIGHT WITH ELEVATED INSTABILITY REMAINING ON
THE BACK EDGE OF THE MCS AS IT WORKS SEWRD. THE MAIN QUESTION IS
TIMING. LATEST WRF-NMM AND WRF-ARW BOTH HAVE SHRA AND TSRA
ARRIVING AFTER 6Z...MAINLY 9-12Z ACRS NC NY SEWRD TO THE
CATSKILLS. THE HRRR ON THE OTHER HAND HAS THE PRECIP SHIELD AND
SOME TSRA ARRIVING MUCH ERLYR...SPREADING FROM NC NY SOUTHWARD TO
THE CATSKILLS AND EVEN NE PA BETWEEN 1Z AND 6Z ABT 4-6 HOURS
SOONER. THE NAM...GFS AND CANADIAN ALL BRING SOME LIGHT PRECIP
INTO THESE AREAS LATE TONIGHT WITH THE RUC A LITTLE FASTER ON THE
ARRIVAL OF THE PRECIP. THUS THE HRRR AND THE RUC TO A LESSER
EXTENT ARE ON AN ISLAND BY THEMSELVES. HOWEVER...JUDGING BY
LATEST RADAR LOOP IT LOOKS LIKE THE HRRR HAS THE BEST HANDLE...BUT
THIS IS A MAJOR DEPARTURE FROM ERLYR FCSTS AND ALL OTHER MODEL
GUIDC AND SOUNDINGS INDICATE THAT IT IS VERY DRY BELOW 10000 FEET.
SO FOR NOW WILL HAVE CHC POPS NRN AND ERN CWA INCREASING AFTR
6Z...BUT WILL RE-EVALUATE AND MAY HAVE TO BUMP UP POPS ERLYR. I WUD
LIKE TO SEE RADAR TRENDS ON THE SRN EDGE OF THIS MCS AND IF THE
PRECIP IS REACHING THE GRND NEXT COUPLE HOURS.
FOR MONDAY...AN UPPER LEVEL WAVE WILL MOVE EASTWARD TWD NY AND PA
IN THE NW UPPER LEVEL FLO PATTERN. CONVECTION ALLOWING
MODELS...ESPECIALLY THE WRF-NMM, AND WRF-ARW AS WELL AS THE NAM
AND HIGHER RES CANADIAN ALL INDICATE SOME POTENTIAL FOR TRAINING
THUNDERSTORMS AS THE LL FLOW WILL BE W-NW AND FAIRLY ALIGNED WITH
THE UPPER LEVEL FLO. BOTH THE CANADIAN AND NAM HAVE A WELL
DEVELOPED JET ENTRANCE REGION CIRCULATION FOR OUR AREA WHEREAS THE
ERLYR EURO AND 12Z GFS REALLY DON/T. MODEL CAPES ARE AVERAGING
ARND 1000 J/KG OR SO WITH MODEST SHEAR VALUES...GENERALLY 25 TO 30
KNOTS IN THE LOWEST 6 KM WITH MOST OF THE SHEAR ACTUALLY BETWEEN 0
AND 3 KM. I CAN EASILY SEE AN MCS EVOLVING OVER OUR REGION MON PM
AND...IN ITS WAKE SOME TRAINING STORMS WITH LOCALLY HEAVY RAINS.
FOR NOW...THINK LIKELY POPS ARE ON ORDER MON PM. THERE IS WAY TOO
MUCH UNCERTAINTY AS TO HEAVY RAINFALL POTENTIAL. NAM AND CMC GIVE
THE REGION A STRIPE OF 1-2 INCHES OF RAIN WHICH SHUDN/T BE MUCH OF
A PROBLEM AT ALL. HOWEVER WILL ALERT FUTURE SHIFTS FOR POTENTIAL
TO RAISE SITUATIONAL AWARENESS. AS FOR SEVERE POTENTIAL...THERE CUD BE
SOME LOCALLY DAMAGING WINDS...BUT AT THIS POINT IT LOOKS LIKE THE
CAPE AND SHEAR FALL SHORT OF WHAT WE WOULD EXPECT FOR AN OUTBREAK.
SPC CONCURS IN THEIR DAY 2 OUTLOOK.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
I KEPT TUESDAY DRY AS NY AND PA IS IN BETWEEN SYSTEMS WITH A SMALL
BUBBLE HIGH OVHD. ALL SYNOPTIC MODELS INDICATE THAT THE MAJORITY
OF THE DAY IS DRY WITH JUST A FEW HUNDREDTHS POSSIBLE IN THE SW
AND FAR NE PART OF OUR CWA.
FOR WEDNESDAY...MODELS ARE IN AGREEMENT THAT ANOTHER MCS AND SHRT
WAVE WILL AFFECT THE REGION. MODEL TIMING AND PLACEMENT IS
UNCERTAIN THIS FAR OUT. SO I HAVE GENERIC CHC POPS FOR SHRA AND
TSRA TO COVER IN LINE WITH NEIGHBORING OFFICES.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
NO MAJOR CHANGES TO THIS PART OF THE FORECAST. THE BROAD...AND
HOT LATE SEASON RIDGE OVER MUCH OF THE WESTERN AND CNTRL CONUS IS
STILL EXPECTED TO EXPAND INTO THE NORTHEAST BY THE END OF THE
PERIOD WITH REGIONAL HIGH TEMPERATURES EXPECTED TO RISE WELL INTO
THE MID 80S OVER NEXT WEEKEND.
THE ADVERTISED FRONTAL SYSTEM...POSSIBLY ACCOMPANIED BY A COMPLEX
SECONDARY LOW DEVELOPMENT ON THE BOUNDARY...IS STILL FORECAST TO
BE MOVING EAST OF THE AREA IN THE WEDNESDAY NIGHT-THURSDAY TIME
FRAME. THE FORECAST WILL STILL FEATURE DECREASING POPS WITH TIME
INTO THURSDAY...THEN WITH THE BROAD RIDGE IN PLACE THURSDAY NIGHT
AND NEXT WEEKEND LOOKS RAIN FREE AND WARMER AT THIS TIME.
&&
.AVIATION /05Z MONDAY THROUGH FRIDAY/...
06Z MON UPDATE... VFR SHOULD PREVAIL INTO THIS AFTN...WITH JUST
SOME UNRESTRICTED -SHRA/SPRINKLES ACRS THE RGN...SPCLY EARLY THIS
MRNG (THROUGH 12-15Z).
THIS AFTN INTO THE EARLY EVE PD...MORE ORGANIZED SHWRS/TSTMS ARE
EXPECTED...PARTICULARLY ACRS NY`S SRN TIER AND NE PA (IMPACTING
MOSTLY KELM/KITH/KBGM/KAVP). THUS...WE`LL CARRY TEMPO GROUPS FOR
MVFR RESTRICTIONS AND TSRA AT THESE FOUR SITES...WITH A PROB30
GROUP FOR NOW AT KSYR/KRME.
LTR THIS EVE/OVERNIGHT...AS A BNDRY COMES THROUGH FROM THE
NW...PCPN SHOULD COME TO AN END. HOWEVER...SOME LWR CIGS ARE
FORESEEN...SO MVFR RESTRICTIONS WERE CARRIED AT ALL SITES EXCEPT
KAVP...STARTING IN THE 03-05Z TIME FRAME.
SFC WINDS MAINLY AOB 5 KT EARLY THIS MRNG...WILL INCREASE OUT OF
THE SW TO 5-10 KT BY 12-15Z...WITH W TO NW WINDS INCREASING
FURTHER...AND BCMG GUSTY THIS AFTN. WINDS WILL SHIFT INTO THE N
AND NE BY LATER THIS EVE (BY 00-03Z).
OUTLOOK...
TUE...MAINLY VFR.
WED...AT LEAST BRIEF RESTRICTIONS PSBL...IN SHRA/TSRA.
THU AND FRI...MAINLY VFR ONCE AGN.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN/HEDEN
SHORT TERM...DJN
LONG TERM...JAB
AVIATION...MLJ/MSE
AREA FORECAST DISCUSSION
NWS BISMARCK ND
600 PM CDT MON AUG 26 2013
.UPDATE...
ISSUED AT 600 PM CDT MON AUG 26 2013
AS OF 2245 UTC...STRONG TO SEVERE THUNDERSTORMS CONTINUE TO
INTENSIFY ACROSS FAR NORTHEAST MONTANA THROUGH DUNN COUNTY IN
NORTH DAKOTA ALONG A WEAK CONVERGENCE LINE. ML CAPE VALUES NEAR
2500 J/KG ARE ANALYZED ALONG THIS LINE ON THE SPC RAPV2
MESOANALYSIS...WHICH APPEARS TO BE HANDLING THE CURRENT
ENVIRONMENT BETTER THAN THE RAPV1. GIVEN DEEP LAYER SHEAR OF 40
KTS...SUPERCELLS ARE LIKELY. THE PRIMARY THREATS ARE DAMAGING
WINDS WITH DOWNDRAFT CAPE VALUES NEAR 1200 J/KG. GIVEN THE HIGH
FREEZING LEVELS AND PWATS...HAIL SURVIVABILITY IS LIMITED. ALSO
MONITORING LOCATIONS NEAR THE SOUTH DAKOTA BORDER ALONG ANOTHER
CONVERGENCE LINE IN A SIMILIAR ENVIRONMENT...WITH THE LATEST 21
UTC HRRR CONTINUING TO SUGGEST CONTINUED GROWTH OF CONVECTION THAT
HAS BEEN INITIATING OVER THE PAST HOUR FOR THESE AREAS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 324 PM CDT MON AUG 26 2013
MAIN CONCERNS THIS SHORT TERM WILL BE THUNDERSTORMS. BROAD FEATURES
INCLUDE A LARGE AND PERSISTENT RIDGE IN THE UPPER ATMOSPHERE. ON THE
WESTERN SIDE OF THE RIDGE A TROPICAL PLUME IS IDENTIFIED ON THE
WATER VAPOR IMAGE. A WEAK SHORTWAVE NOW MOVING THROUGH NORTHEAST
WYOMING WILL SUPPORT CONVECTION THIS EVENING AND OVERNIGHT. AS THE
SHORT WAVE TROUGH TRANSITS ACROSS THE RIDGE EXPECT AN INCREASE IN
THUNDERSTORMS ...WHICH SO FAR TODAY APPEAR TO BY LIMITED BY THE WARM
MID LEVEL TEMPERATURES. WITH THE ADDED LIFT FROM THE SHORTWAVE
EXPECT THUNDERSTORMS TO BECOME MORE ACTIVE LATE THIS AFTERNOON AND
EVENING...MAINLY SOUTH CENTRAL AND SOUTHEAST. MULTIPLE WEAK OUTFLOW
BOUNDARIES EXIST ACROSS THE SOUTH CENTRAL...AND CLOUDS ACROSS NORTH
DAKOTA SUPPORTING DIFFERENTIAL HEATING AND ENHANCING THE THERMAL
BOUNDARY.
TONIGHT...THUNDERSTORM THREAT WILL MOVE EAST. ENDED THE CHANCE OF
THUNDERSTORMS AFTER 1 AM. SOUTHEAST UPSLOPE FLOW AND WEAK SHORTWAVE
ENERGY IN FLOW ALOFT WILL SUPPORT A SLIGHT CHANCE OF THUNDERSTORMS
SOUTHWEST TUESDAY AFTERNOON.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 324 PM CDT MON AUG 26 2013
MAIN FORECAST ISSUES IN THE LONG TERM WILL BE DAYTIME HIGH
TEMPERATURES AND PERIODIC THUNDERSTORM CHANCES.
THE OVERALL UPPER LEVEL PATTERN REMAINS NEARLY UNCHANGED WITH A
CONTINUED GOOD AGREEMENT AMONG BOTH THE ENSEMBLE AND DETERMINISTIC
MODELS. FINER DETAILS CONTINUE TO COME TO A CONSENSUS AMONG THE
MODELS EARLY IN THE PERIOD...BUT SIGNIFICANT DIFFERENCES STILL EXIST
OVER THE WEEKEND AND EARLY NEXT WEEK. EXCEPT FOR A FEW ADJUSTMENTS
TO BUMP UP POPS WHERE MODELS ARE MORE IN LINE...STILL UTILIZED A
MODEL BLEND SOLUTION FOR POPS DURING MOST OF THE LONG TERM PERIOD.
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...BETTER THUNDERSTORM CHANCES
APPEAR IN STORE TUESDAY NIGHT THROUGH WEDNESDAY NIGHT WHEN A FEW
UPPER LEVEL WAVES MOVE INTO THE NORTHERN PLAINS AND TEMPORARILY
BREAKS DOWN THE UPPER LEVEL RIDGE. DETERMINISTIC MODELS INDICATE
INCREASED WARM ADVECTION WEDNESDAY AFTERNOON AND EVENING AHEAD OF
SURFACE LOW PRESSURE THAT DEVELOPS OVER THE WESTERN DAKOTAS. POPS
ARE GREATEST WEDNESDAY IN THE WEST HALF DURING THE DAY...WITH HIGHER
CHANCE POPS SPREADING EAST WEDNESDAY NIGHT AS THE INCREASED WARM
ADVECTION AND COOLING UPPER LEVEL TEMPERATURES WITH THE SHORTWAVES
SHOULD SUSTAIN CONVECTION AS IT TRANSLATES EAST.
THURSDAY AND THURSDAY NIGHT...THE LAST OF THIS ROUND OF UPPER LEVEL
SHORTWAVE ENERGY IMPULSES IS PROGGED TO MOVE EAST ACROSS THE STATE
THURSDAY BEFORE EXITING THE REGION THURSDAY AFTERNOON/NIGHT. UPPER
LEVEL RIDGING QUICKLY REBOUNDS ON THURSDAY NIGHT.
FRIDAY THROUGH MONDAY...THE MODELS IN GENERAL KEEP THE UPPER LEVEL
RIDGE ESTABLISHED OVER THE CENTRAL US THROUGH THE WEEKEND. THE
MODELS DIFFER AFTER THIS...WITH THE ECMWF KEEPING THE RIDGE IN PLACE
WHILE THE GFS SOLUTION DEPICTS THE RIDGE BROADENING AND MOVING EAST.
THUS WILL CONTINUE WITH A MODEL BLEND HERE WHICH GIVES MAINLY SLIGHT
CHANCE POPS EACH DAY.
TEMPERATURES SHOULD REMAIN ABOVE AVERAGE THROUGH SATURDAY WITH HIGHS
MAINLY 85-90 NORTH TO LOW TO MID 90S SOUTH. THE MODEL BLEND HINTS OF
TEMPERATURES MOVING BACK TOWARDS SEASONABLE SUNDAY/MONDAY WITH HIGHS
75-85 NORTH AND IN THE 80S SOUTH.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 600 PM CDT CDT MON AUG 26 2013
ISOLATED TO SCATTERED STRONG TO SEVERE THUNDERSTORMS ACROSS
WESTERN AND SOUTHERN NORTH DAKOTA WILL MOVE EAST THROUGH THE
EVENING. AREAS OF IFR FOG ARE ALSO POSSIBLE TONIGHT GIVEN LIGHT
WINDS AND THE HIGH HUMIDITY IN PLACE. WILL MONITOR RADAR TRENDS TO
AMEND TAFS FOR THUNDERSTORM IMPACTS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...WAA
LONG TERM...JV
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1224 AM CDT MON AUG 26 2013
.UPDATE...
ISSUED AT 1224 AM CDT MON AUG 26 2013
LATEST LOCAL/REGIONAL RADAR SHOWS SHOWERS DWINDLING OVER OUR FAR
SOUTHEAST ZONES AND WILL CONTINUE TO SHOW THAT TREND FROM PREVIOUS
FORECAST. UPSTREAM RADAR PER RAPID CITY AND BOWMAN ND SHOW THE
BEGINNING SIGNS OF ANOTHER ROUND OF SHOWERS AND EVENTUALLY SOME
THUNDERSTORMS THAT ARE DEVELOPING AND MOVING NORTHEAST WITH TIME.
THE HIGH RESOLUTION HRRR...4KM NAM...00Z NAM12 AND TO AN EXTENT
THE 00Z GFS ALL SHOW MULTIPLE SHORTWAVES TO SLIDE OVER THE LEE
SIDE TROUGH IN SOUTHEAST MONTANA OVERNIGHT PRODUCING AN AREA OF
SHOWERS AND THUNDERSTORMS AS MENTIONED ABOVE...MOVING INTO OUR
SOUTHWEST ZONES BETWEEN 09Z AND 12Z MONDAY. THIS AREA EXPANDS
NORTHEAST INTO WESTERN AND CENTRAL NORTH DAKOTA WHICH THE CURRENT
FORECAST GRIDS SHOW. IT APPEARS THAT THE DAYLIGHT HOURS MONDAY
WILL BE THE PRIME TIME FOR PRECIPITATION...THEN DECREASING FROM
WEST TO EAST BY MID TO LATE AFTERNOON. MINIMAL UPDATES NEEDED
OTHER THAN ADDING SOME MENTION OF PRECIPITATION INTO THE SOUTHWEST
TOWARD 12Z MONDAY.
UPDATE ISSUED AT 1000 PM CDT SUN AUG 25 2013
GIVEN THE LATEST RADAR TRENDS AND INCOMING 00 UTC
GUIDANCE...REDUCE POPS TO JUST THE FAR SOUTH CENTRAL AND SOUTHERN
JAMES RIVER VALLEY FOR THE REMAINDER OF THE NIGHT. OTHERWISE...THE
REST OF THE FORECAST IS ON TRACK...WITH A MILD OVERNIGHT EXPECTED
WITH LOWS IN THE MID TO UPPER 60S FOR MOST LOCATIONS.
UPDATE ISSUED AT 752 PM CDT SUN AUG 25 2013
AS OF 0045 UTC...THUNDERSTORMS REMAIN FOCUSED FROM LEMMON TO
TIMBER LAKE SOUTH DAKOTA WHERE LOW LEVEL CONVERGENCE IS MAXIMIZED.
AGAIN...THE HRRR HAS HAD A GOOD HANDLE ON THE CONVECTION THIS
EVENING AND WILL FOLLOW ITS LATEST 23 UTC RUN FOR POPS...WHICH
GENERALLY REMAIN ALONG AND SOUTH OF I-94 WITH THE ONSET OF A MODEST
LOW LEVEL JET. THE OVERALL SEVERE THREAT IS MARGINAL ACROSS FAR
SOUTHERN NORTH DAKOTA AS THE BOUNDARY LAYER BEGINS TO STABILIZE.
HOWEVER...WILL HAVE TO MONITOR FOR STRONG WINDS GIVEN DOWNDRAFT
CAPE VALUES NEAR 1200 J/KG.
UPDATE ISSUED AT 520 PM CDT SUN AUG 25 2013
QUICK UPDATE TO INCREASE AND EXPAND POPS ACROSS WESTERN AND
CENTRAL NORTH DAKOTA FOR THE REMAINDER OF THE EVENING AND
OVERNIGHT. SURFACE BASED CONVECTION HAS BEEN INCREASING ACROSS
SOUTHWEST NORTH DAKOTA AND NORTHWEST SOUTH DAKOTA SINCE 2130 UTC
GIVEN THE LOSS OF CAPPING AND INCREASING UPPER LEVEL FORCING WITH
THE SHORTWAVE ENTERING WESTERN NORTH DAKOTA EVIDENT ON THE LATEST
WATER VAPOR IMAGERY. DEEP LAYER SHEAR ON THE ORDER OF 30-35 KTS
SUPPORTS THE POTENTIAL FOR PERHAPS A SUPERCELL OR TWO...WITH ML
CAPE VALUES AROUND 1500 J/KG. WHILE HIGH FREEZING LEVELS LIMIT THE
HAIL THREAT...DOWNDRAFT CAPE VALUES NEAR 1400 J/KG SUGGEST A
DAMAGING WIND THREAT WITH THE STRONGER STORMS. THE 18 UTC NAM AND
20 UTC HRRR ARE HANDLING THE CONVECTION WELL...WITH THE HRRR
SUGGESTING THE CONVECTION WILL PROPAGATE INTO BISMARCK AND MANDAN
LATER TONIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 317 PM CDT SUN AUG 25 2013
LATE SUNDAY AFTERNOON...SURFACE HIGH PRESSURE WAS ACROSS SOUTHERN
MANITOBA. A WEAK COLD FRONT WAS SLIDING SOUTH ACROSS CENTRAL NORTH
DAKOTA. ON SATELLITE...WATER VAPOR IMAGERY SHOWS A SHORTWAVE TROUGH
MOVE THROUGH WYOMING INTO CENTRAL MONTANA. THIS FEATURE IS
SUPPORTING CONVECTION ACROSS EASTERN MONTANA. SOME SHOWERS AND
ISOLATED THUNDERSTORMS SHOULD ENTER WEST CENTRAL AND NORTHWEST NORTH
DAKOTA LATE THIS AFTERNOON AND EVENING. THEN PROGRESSIVELY TRACKED
THE SLIGHT CHANCE TO CHANCE OF THUNDERSTORMS INTO WESTERN NORTH
DAKOTA OVERNIGHT AND INTO CENTRAL NORTH DAKOTA MONDAY. WITH THE
BASIC RIDGE PATTERN IN PLACE OVER THE CENTRAL AND NORTHERN
PLAINS...CONTINUED WARM TEMPERATURES EXPECTED ON MONDAY...HOWEVER
WITH COLD FRONT BRINGING A SLIGHT RELIEF WITH HIGHS IN THE UPPER 80S
NORTH TO LOWER 90S SOUTH ON MONDAY.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 317 PM CDT SUN AUG 25 2013
MAIN FORECAST ISSUES IN THE LONG TERM WILL BE DAYTIME HIGH
TEMPERATURES AND PERIODIC THUNDERSTORM CHANCES.
THERE IS A CONTINUED GOOD AGREEMENT AMONG BOTH THE ENSEMBLE AND
DETERMINISTIC MODELS IN THE MEAN UPPER LEVEL FLOW WHICH FEATURES A
STRONG RIDGE OVER THE CENTRAL U.S. THAT RETROGRADES FROM THE
MISSOURI VALLEY WEST INTO THE SOUTHERN PLAINS THROUGH THE PERIOD.
NORTH DAKOTA WILL REMAIN NEAR THE APEX OF THE RIDGE THROUGH THE LONG
TERM FORECAST PERIOD...WHICH WILL CONTINUE TO INDICATE ABOVE AVERAGE
DAYTIME HIGH TEMPERATURES. SOUTHERN PORTIONS OF THE CWA COULD FLIRT
WITH HEAT ADVISORY CRITERIA LATER IN THE WEEK. IN ADDITION...ALMOST
DAILY THUNDERSTORM CHANCES CAN BE EXPECTED WITH HIGH CAPES EVERY DAY
BUT A STRONG CAP LIMITING CONVECTION.
THE DETERMINISTIC MODELS CONTINUE TO ADVERTISE A FEW...MORE
SIGNIFICANT...WAVES WORKING THROUGH THE MEAN RIDGE AND BRINGING
BETTER PRECIPITATION CHANCES. ON MONDAY AND INTO MONDAY NIGHT THE
ECMWF/GEM APPEAR STRONGER WITH A WAVE MOVING INTO NORTH DAKOTA AND
BRING QPF ACROSS THE NORTH. THE SOUTH MAY REMAIN CAPPED UNDER WARM
MID LEVEL TEMPERATURES.
WAVES CONTINUE TO WORK THROUGH THE MEAN RIDGE ON WEDNESDAY THROUGH
SATURDAY BUT TIMING AND PLACEMENT DIFFERENCES CONTINUE BETWEEN
MODELS AND MODEL RUNS. THEREFORE WILL CONTINUE TO UTILIZE A BLENDED
SOLUTION FOR PRECIPITATION. THIS WILL MEAN BETTER CHANCES WEDNESDAY
THROUGH THURSDAY AFTERNOON...THEN CHANCES ARE ON AND OFF FRIDAY
NIGHT THROUGH SUNDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1224 AM CDT MON AUG 26 2013
SCT TO BKN MID LEVEL CLOUDS ALONG WITH A CHANCE FOR SHOWERS AND
THUNDERSTORMS WILL CONTINUE THIS TAF PERIOD. EXPECTING SOME
SHOWERS/THUNDERSTORMS TO AFFECT KDIK BY 12Z MONDAY...WITH A
VCTS AT KISN. THE AREA OF SHOWERS AND THUNDERSTORMS SHOULD DEVELOP
FURTHER AND REACH KMOT/KBIS BETWEEN 15Z AND 18Z MONDAY. WILL
MONITOR AND SEE HOW THE AREA OF PRECIPITATION DEVELOPS TONIGHT AND
MAKE FURTHER ADJUSTMENTS ON TIMING FOR THE 12Z TAF FORECAST. FOR
NOW HAVE INDICATED AND MAINTAINED THE VCSH/VCTS AT ALL AERODROMES
EXCEPT KDIK WHERE CONFIDENCE IS A BIT HIGHER NOW THAT AN AREA OF
SHOWERS AND THUNDERSTORMS WILL REACH THEM BY 12Z MONDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...WAA
LONG TERM...JV
AVIATION...KS
AREA FORECAST DISCUSSION
NWS MEDFORD OR
1040 PM PDT SUN AUG 25 2013
.DISCUSSION...NEW EVENING UPDATE. THE LATEST RAP MODEL IS SHOWING
THE CONVECTION TO CONTINUE UP THE SPINE OF THE CASCADES THROUGH 12Z.
ALTHOUGH IT HAS WHAT SEEMS TO BE UNREALISTICALLY HIGH QPF
AMOUNTS...IT IS INDEED HAPPENING AT THIS TIME AND OTHER MODELS ARE
NOT PICKING UP ON THIS. HAVE UPDATED TO ADD SLIGHT CHANCE POPS IN
THAT AREA WITH AN OCCASIONAL BOLT OF LIGHTNING POSSIBLE...AS WELL AS
ADDING FOG TO THE FULL COAST THAT IS ALREADY THERE.
PREVIOUS DISCUSSION...THE LATEST WATER VAPOR IMAGE SHOWS THE UPPER
TROUGH OVER SOUTHWEST OREGON AND WILL CONTINUE TO MOVE NORTHEAST.
THUNDERSTORMS AHEAD OF THE TROUGH ARE MAINLY CENTERED OVER THE
NORTHERN CASCADES...KLAMATH COUNTY AND NORTHEAST LAKE COUNTIES AND
ARE MOVING NORTH TO NORTHEAST. COULD NOT RULE OUT THE POTENTIAL FOR
A FEW STORMS TO REACH SEVERE LEVEL FOR THE NEXT 4-6 HOURS...BUT THIS
WILL BE EXCEPTION NOT THE NORM.
ISOLATED THUNDERSTORMS ARE STARTING TO POP UP IN CENTRAL MODOC
COUNTY. MEANWHILE WERE STARTING TO SEE SOME CLEARING WITH MORE
CUMULUS DEVELOPMENT OVER SOUTHWEST OREGON AND SISKIYOU COUNTY WITH A
FEW CELLS STARTING TO DEVELOP. LATEST MESOSCALE ANALYSIS SHOWS LOW
CINS AND HIGHER SURFACE CAPE VALUES NOSING INTO WESTERN SISKIYOU
COUNTY. HOWEVER 700-500 MB LAPSE RATES ARE NOT AS STEEP WHICH WAS
PROBABLY A RESULT IN LATENT HEAT RELEASE FROM THIS MORNINGS
PRECIPITATION. THIS COULD BE THE LIMITING FACTOR FOR ADDITIONAL
STORM DEVELOPMENT UNLESS THE CAP BREAKS.
THE ABOVE MENTIONED UPPER TROUGH MOVES NORTH THIS EVENING AND
ACTIVITY SHOULD BEGIN TO DECREASE FROM SOUTH TO NORTH AS THE
ATMOSPHERE BECOMES STABLE. MOST IF NOT ALL PRECIPITATION WILL
SHIFT NORTH OF THE FORECAST AREA AROUND MIDNIGHT.
THE LONGWAVE TROUGH FOR MOST OF NEXT WEEK SHOULD REMAIN OFFSHORE
WITH A SOUTHWEST FLOW ALOFT. SEVERAL WEAK FRONTS WILL BRUSH BY
OVER THE NORTHWEST PART OF THE FORECAST AREA KEEPING AT LEAST A
SLIGHT CHANCE OF RAIN. THE FIRST IS EXPECTED TO MOVE THROUGH MONDAY
NIGHT, THE NEXT ONE WEDNESDAY NIGHT/THURSDAY. ELSEWHERE IT SHOULD BE
DRY WITH NEAR NORMAL TEMPERATURES.
EC AND GFS STILL DIFFER NEXT WEEKEND, BUT NOT AS MUCH AS YESTERDAY.
THE POSITION AND TIMING OF DEEPENING TROUGH AND UPPER LOW ARE
DIFFERENT AND THE EC STILL SHOWING THE UPPER LOW PROGRESSING THROUGH
THE PAC NW. MEANWHILE THE GFS DROPS THE UPPER LOW SOUTH ALONG THE
OREGON COAST THEN MOVING INLAND SUNDAY. DID ADJUST POPS HIGHER
SUNDAY WITH BOTH MODELS SHOWING SOME QPF AND MADE LITTLE CHANGES IN
THE EXTENDED. -PETRUCELLI
&&
.AVIATION...ISOLATED SHOWERS AND THUNDERSTORMS WILL LINGER LATE THIS
EVENING (UNTIL AROUND 06Z) FROM THE CASCADES EASTWARD. THE AIR MASS
WILL STABILIZE OVERNIGHT. MARINE STRATUS HAS ALREADY DEVELOPED AT
THE COAST. LIFR CEILINGS AND VISIBILITIES WILL CONTINUE AT THE COAST
OVERNIGHT INTO MID-MORNING (UNTIL AROUND 18Z). ALSO, MVFR CEILINGS
ARE EXPECTED TO SPREAD INTO THE UMPQUA BASIN AFTER MIDNIGHT AND ALSO
LINGER UNTIL AROUND 18Z. PATCHY GROUND FOG IS POSSIBLE NEAR KLMT
AROUND SUNRISE (BETWEEN 12Z AND 16Z).
OTHERWISE...CONDITIONS ARE EXPECTED TO REMAIN VFR OVER THE NEXT 24
HOURS WITH DECREASING CLOUDS LATE TONIGHT INTO MONDAY. WEAK
INSTABILITY IS EXPECTED MONDAY AFTERNOON IN THE VICINITY OF CRATER
LAKE WITH A SLIGHT CHANCE OF THUNDERSTORMS.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS FROM 9 AM TO
5 PM PDT MONDAY FOR PZZ370-376.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 9 AM TO 8 PM PDT
MONDAY FOR PZZ370-376.
$$
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
814 PM CDT TUE AUG 27 2013
.UPDATE...
NO MAJOR CHANGES THIS EVENING. A FEW THUNDERSTORMS OUT WEST APPEAR
TO BE ON THE WANE...AND WITH LACK OF DECENT LLJ OVER THE
EAST...HAVE DOUBTS ABOUT THE HRRR BEING SO AGGRESSIVE IN BRINGING
CONVECTION EAST. HOWEVER WILL KEEP POPS GOING JUST IN CASE. HEAT
ADVISORY HAS BEEN ALLOWED TO EXPIRE.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TONIGHT THROUGH THURSDAY NIGHT
THE MAIN FORECAST CHALLENGES WILL BE TEMPERATURES THROUGH THE
PERIOD AND PRECIP CHANCES TONIGHT AND WEDNESDAY MORNING.
A SHORTWAVE IS RIDING OVER THE RIDGE TONIGHT. COMBINED WITH A
PLUME OF MOISTURE SHOOTING INTO THE WESTERN DAKOTAS THUNDERSTORMS
ARE ALREADY DEVELOPING THIS AFTERNOON. THE MAGIC NUMBER SEEMS TO
BE H7 TEMPS OF +12C OR LESS. THAT LINE WILL STRETCH FROM JUST WEST
OF BROWN COUNTY SOUTHWEST TO DEWEY COUNTY. AREAS NORTHWEST OF
THERE ARE THE MOST LIKELY TO SEE STRONG TO SEVERE THUNDERSTORMS
THIS EVENING WITH LARGE HAIL AND STRONG WINDS THE MAIN THREATS.
THERE IS VERY LITTLE CIN...2000 J/KG OF CAPE AND SHEAR AROUND 45
KTS FOR THE STORMS TO WORK WITH. STUCK VERY CLOSE TO THE NAM 12
SOLUTION WHICH KEEPS THE MAJORITY OF STORMS ALONG THE NORTHERN
TIER BUT PROGRESSES THEM EASTWARD OVERNIGHT INTO WEST CENTRAL
MINNESOTA FOR WEDNESDAY MORNING.
DUE TO THE POTENTIAL PRECIP...HIGH TEMPS ON WEDNESDAY WILL BE A
LITTLE TRICKY. CLOUD COVER COULD SUPPRESS THEM SLIGHTLY IN THE
EAST. BY THURSDAY DRIER AIR WILL MOVE IN AND HIGH TEMPERATURES
WILL RISE BACK INTO THE UPPER 90S...CLOSE TO 100 IN THE SOUTHWEST
COUNTIES.
.LONG TERM...FRIDAY THROUGH TUESDAY.
THE MEDIUM RANGE MODELS CONTINUE THE TREND FOR THE STRONG UPPER
LEVEL RIDGE FLATTENING THEN REBOUNDING FARTHER WEST ON THE
WEEKEND. THIS WILL RESULT IN THE HOT TEMPERATURES CONTINUING
UNTIL AT LEAST SATURDAY...WITH A NICE COOL-DOWN ON SUNDAY INTO
THE 80S BEFORE TEMPS BEGIN TO RISE AGAIN TUESDAY.
THE MAIN QUESTION IS CHANCES OF THUNDERSTORMS SATURDAY AS SYSTEM
MOVES THROUGH. THE SYSTEM AND ASSOCIATED COLD FRONT LOOK FAIRLY
DRY FOR THE FORECAST AREA ATTM...AND TIMING DOES NOT APPEAR TO BE
FAVORABLE. AS HAS BEEN THE CASE THIS SUMMER...THE SYSTEM LOOKS
BETTER FARTHER NORTH FOR ANY THUNDERSTORMS. WILL KEEP LOW POPS
GOING FOR DURING THE DAY SATURDAY.
&&
.AVIATION...
00Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
MOSTLY VFR CONDITIONS SHOULD PREVAIL THROUGH TONIGHT. THERE COULD
BE SOME MVFR FOG IN THE EAST...AND A FEW THUNDERSTORMS OUT WEST.
ANY THUNDERSTORM COULD PRODUCE IFR CONDITIONS FOR A RELATIVELY
SHORT AMOUNT OF TIME. KMBG HAS THE HIGHEST PROBABILITY OF SEEING
THUNDERSTORMS THIS EVENING.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...TDK
SHORT TERM...WISE
LONG TERM...SCARLETT
AVIATION...TDK
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
629 PM CDT TUE AUG 27 2013
.DISCUSSION...
See aviation discussion below.
&&
.AVIATION...
VFR conditions will prevail the next 24 hours. With the tropical
moisture in place lowered clouds will move into the area early
morning, before sunrise. Model soundings suggest cigs should stay
above 3000 ft. NAM MOS, especially at Brady, is suggesting cigs
could go lower, but at this point I do not have the confidence to go
MVFR. After sunrise, cigs should begin to burn off by mid morning.
Winds will be light and mostly out of the south to southeast through
the TAF period.
&&
.PREV DISCUSSION... /ISSUED 340 PM CDT TUE AUG 27 2013/
SHORT TERM...(Tonight and Wednesday)
Isolated shower activity will be ending this evening, as an easterly
wave moves northwest. HRRR model seems to have been the better
model, indicating rapid weakening showers this afternoon. The NAM
and GFS models had more extensive coverage this afternoon over the
Big Country and Concho Valley. In any case...all models show
precipitation ending by early evening with loss of the suns heating.
Some patchy stratus possible late tonight and early Wednesday
morning...due to moist vegetation and light winds. Temperatures
rebound into the lower and mid 90s Wednesday with dry conditions and
and mostly sunny skies.
LONG TERM...(Thursday through Tuesday)
Dry and hot weather to prevail through the weekend.
The ECMWF and the GFS are still in good agreement, indicating that
once the wave moves out of the area tomorrow, the upper level high
pressure will settle back into the area. With the high dominating
the weather across the southern plains, looks like dry conditions
will prevail. The center of the high pressure will shift from the
mid Mississippi Valley on Wednesday, to Texas on Thursday, and into
the southern Rockies for the weekend. Since we don`t see the center
of the high sit directly over West Central Texas, temperatures are
more likely to be in the mid and upper 90s to near 100 rather than
something much warmer. But in any case, dry and warmer than normal
conditions will be the rule.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 71 95 71 97 72 / 10 5 5 5 5
San Angelo 70 93 70 96 71 / 10 5 5 5 5
Junction 70 93 70 95 70 / 10 5 5 5 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
Reimer
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
938 PM CDT TUE AUG 27 2013
.UPDATE...
THUNDERSTORMS DEVELOPED ALONG THE COLD FRONT DROPPING SOUTH THROUGH
CENTRAL WISCONSIN THIS EVENING. A FEW WERE STRONGER WITH A HAIL
THREAT AND WERE SHOWING DECENT MESOSCALE ROTATION IN THE LOWER
LEVELS. WHILE STORMS ARE STILL ONGOING ACROSS THE FAR NORTHERN MKX
FORECAST AREA FROM MARQUETTE TO FOND DU LAC TO SHEBOYGAN COUNTIES...
THEY ARE SHOWING A WEAKENING TREND BUT PULSE UP STRONGER NOW AND
THEN.
EXPECT THUNDERSTORM ACTIVITY TO DISSIPATE JUST AFTER MIDNIGHT PER
THE LATEST MESOSCALE MODELS AND LACK OF A DECENT VORT MAX OR NOSE OF
A LOW LEVEL JET IN THE AREA AND ALSO DEEP MOISTURE.
QUIET WEATHER IS EXPECTED WEDNESDAY...WITH SOME DIURNAL CUMULUS
POSSIBLE IN THE AFTERNOON. HIGHS WILL STILL REACH WELL INTO THE 80S
AWAY FROM THE LAKE...WITH AROUND 80 NEAR IT. SLIGHTLY DRIER AIR WILL
KEEP HEAT INDICES BELOW 95.
&&
.AVIATION/06Z TAFS/...
STORMS ALONG A WEAK COLD FRONT SLOWLY MOVING SOUTHWARD TO THE WI/IL
BORDER OVERNIGHT WERE NEAR SHEBOYGAN AND FOND DU LAC AT 930 PM. THEY
WILL GRADUALLY DISSIPATE THROUGH MIDNIGHT...MOST LIKELY REMAINING
OUT OF MSN AND ENW...BUT COULD CLIP UES AND MKE AS THEY SAG
SOUTHEAST.
MVFR/IFR VISIBILITIES POSSIBLE IN ANY STORMS OVERNIGHT. FOG WITH
MVFR/IFR VISIBILITIES POSSIBLE BETWEEN 06Z AND 14Z WEDNESDAY. VFR
CONDITIONS RETURN FOR THE REST OF WEDNESDAY AS HIGH PRESSURE MOVES
INTO THE REGION.
&&
.MARINE...
STORMS FROM SHEBOYGAN TO PORT WASHINGTON WILL GRADUALLY SAG
SOUTHWARD THROUGH MIDNIGHT AND GRADUALLY DISSIPATE AFTER MIDNIGHT.
SHOULD SEE AT LEAST PATCHY FOG DEVELOP LATER TONIGHT INTO EARLY
WEDNESDAY WITH A MOIST AIRMASS OVER THE COOL LAKE WATERS. SOME
POTENTIAL FOR MORE WIDESPREAD FOG DURING THIS TIME.
&&
.PREV DISCUSSION... /ISSUED 326 PM CDT TUE AUG 27 2013/
SHORT TERM...
TONIGHT AND WEDNESDAY...FORECAST CONFIDENCE IS MEDIUM.
HEAT ADVISORY REMAINS IN EFFECT UNTIL 01Z WEDNESDAY. SEVERAL
AUTOMATED SITES HAVE ALREADY REACHED THE 100 DEGREE HEAT INDEX
VALUE...AND MORE SHOULD REACH OVER THE NEXT FEW HOURS. GOOD MIXING
WITH SOUTHWEST WINDS HAVE HELPED TEMPERATURES RISE INTO THE LOWER TO
MID 90S. MADISON MAY GET CLOSE TO RECORD HIGH OF 95.
COLD FRONT IS EXPECTED TO SHIFT SOUTHWARD THROUGH THE AREA MAINLY
THIS EVENING. HRRR AND WRF 4KM MODELS NOW BRING THE FRONT THROUGH
THE AREA BETWEEN 00Z AND 06Z WEDNESDAY. THE HRRR IS SHOWING LITTLE
IN THE WAY OF ANY SHOWER/STORM ACTIVITY...WITH THE WRF 4KM MODEL
SHOWING A BROKEN LINE OF WEAK TO MODERATE SHOWERS/A FEW STORMS WITH
THE FRONT. UPWARD VERTICAL MOTION WITH THE FRONT IS EXPECTED TO BE
SOMEWHAT WEAK...WITH THE NAM TOO AGGRESSIVE WITH LOW LEVEL
FRONTOGENESIS RESPONSE.
500MB VORTICITY MAXIMUM OVER NORTHERN WISCONSIN IS EXPECTED TO SLIDE
SOUTHEAST AND CLIP THE NORTHEAST PORTIONS OF THE FORECAST AREA LATE
THIS AFTERNOON AND EARLY THIS EVENING. ADJUSTED AREA FORECAST
SOUNDINGS SHOWING CAP NEARLY MIXING OUT BY 22Z TUESDAY...WITH AT
LEAST 2000 J/KG MEAN LAYER CAPE AND DEEP LAYER SHEAR OF 30 TO 40
PLUS KNOTS...BEST SHEAR TOWARD SHEBOYGAN. SOME INDICATION FOR
ROTATING STORMS PER SPC SSEO PAGE AS WELL. IF CONVECTION DOES
DEVELOP...SEVERE STORMS ARE POSSIBLE GIVEN THESE PARAMETERS...WITH
STRONG WINDS AND LARGE HAIL THE MAIN HAZARDS. SEE LATEST SPC DAY 1
OUTLOOK AND RECENT MESOSCALE DISCUSSION FOR MORE INFORMATION.
GIVEN SOME UNCERTAINTY WITH HOW MUCH CONVECTION WILL
FORM...CONTINUED CHANCE POPS IN THE NORTHERN AND EASTERN PORTIONS OF
THE AREA...CLOSEST TO THE PASSING 500MB VORTICITY MAXIMUM AND BETTER
SHEAR.
WARM TEMPERATURES REMAIN ACROSS THE AREA AFTER FRONTAL PASSAGE LATER
TONIGHT INTO WEDNESDAY...AS WELL AS DEW POINTS IN THE UPPER 60S TO
LOWER 70S. SOME CONCERN WITH CLOUDS OVER NORTHERN WISCONSIN WILL
PUSH SOUTHWARD LATER TONIGHT AND LINGER INTO WEDNESDAY. BROUGHT IN
THESE CLOUDS LATER TONIGHT...BUT MIXED THEM OUT WEDNESDAY. WINDS
WILL SHIFT TO THE NORTH NORTHEAST DURING LATER TONIGHT INTO
WEDNESDAY. ANY FOG THAT DEVELOPS SHOULD REMAIN PATCHY...THOUGH GIVEN
HIGH DEW POINTS MAY BECOME MORE WIDESPREAD. LATER SHIFTS WILL HAVE
TO MONITOR.
QUIET WEATHER IS EXPECTED WEDNESDAY...WITH SOME DIURNAL CUMULUS
POSSIBLE IN THE AFTERNOON. HIGHS WILL STILL REACH WELL INTO THE 80S
AWAY FROM THE LAKE...WITH AROUND 80 NEAR IT.
WEDNESDAY NIGHT THROUGH SATURDAY...FORECAST CONFIDENCE MEDIUM
THE BROAD UPPER RIDGE WILL BE CENTERED OVER THE SOUTH CENTRAL USA THROUGH
THE PERIOD WITH NW FLOW ALOFT OVER WI. AT THE SFC...HIGH PRESSURE
WILL PREVAIL OVER SRN WI WED NT AND THU...BUT HIGH CLOUDS WILL
INCREASE ON THU AS A SLOW MOVING WAVE OF LOW PRESSURE APPROACHES
FROM THE NW. THE HIGH CLOUDS MAY KEEP TEMPS DOWN JUST A LITTLE FOR
THU...BUT STILL A WARM AND HUMID DAY.
A SLOW MOVING WAVE OF LOW PRESSURE WILL THEN TRACK ACROSS THE
REGION FROM THU NT INTO FRI...BUT ON SOME MODELS COULD LINGER INTO
SAT. A COUPLE WEAK VORTICITY MAXIMUMS WILL HELP GUIDE THE LOW SEWD
DURING THIS PERIOD. BEST TIME PERIOD FOR PCPN CHANCES IS THU NT
AND FRI WHEN LOW TO MID LEVEL WARM ADVECTION AND FRONTOGENESIS
AFFECTS THE REGION. SHOWALTER INDICES INCREASE TO -4C FOR LATE THU
NT WHILE LIS FOR FRI COULD REACH -8C. EXPECT THIS LIFT AND
INSTABILITY TO OVERCOME WEAK CAPPING SO POPS MAX OUT AROUND 50-60
PERCENT EITHER THU NT OR FRI. LOW POPS THEN LINGER INTO SATURDAY
SINCE LOW COLD BE SLOW TO DEPART. MAX HEAT INDICES DURING THIS
TIME WILL RANGE FROM THE MID 80S TO MID 90S WITH GREATEST HEAT
OVER SOUTH CENTRAL WI. SOME COOLING IS EXPECTED EACH DAY IN FAR
ERN WI VIA THE LAKE MI LAKE BREEZE.
LONG TERM...
SUNDAY THROUGH TUESDAY...FORECAST CONFIDENCE MEDIUM
EXTENDED MODELS CONTINUE TO PRODUCE STRONG CYCLOGENESIS OVER SRN
CANADA FOR THE WEEKEND. THE LOW WILL MOVE EAST ACROSS SRN CANADA
WITH THE TRAILING COLD FRONT EXPECTED TO ARRIVE OVER SRN WI EITHER
SUN OR SUN NT. MODELS ARE STILL HAVING A DIFFICULT TIME ON THE
STRENGTH OF COOLING WITH THE FROPA BUT OVERALL MUCH COOLER TEMPS
ARE EXPECTED FOR EARLY NEXT WEEK COMPARED TO A COUPLE DAYS AGO.
HIGH TEMPS IN THE 70S ARE FORECAST FOR LABOR DAY AND TUE. POPS
CHANCES REMAIN LOW WITH THE MOSTLY DRY FROPA AND THEN DRY AFTER
FROPA.
AVIATION/00Z TAFS/...
PREVAILING VFR CONDITIONS EXPECTED THROUGH
THIS EVENING...WITH MVFR/IFR VISIBILITIES POSSIBLE IN ANY STORMS
WITH PASSING COLD FRONT. FOG WITH MVFR/IFR VISIBILITIES POSSIBLE
BETWEEN 06Z AND 14Z WEDNESDAY. VFR CONDITIONS RETURN FOR THE REST OF
WEDNESDAY...AS HIGH PRESSURE MOVES INTO THE REGION.
SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE BETWEEN 00Z AND 06Z
WEDNESDAY AT TAF SITES...BEST CHANCES AT THE EASTERN SITES. SOME
UNCERTAINTY IF STORMS WILL FORM AND HOW WIDESPREAD THEY WILL BE...SO
WILL LEAVE VICINITY WORDING IN TAFS FOR NOW. MVFR/IFR VISIBILITIES
POSSIBLE WITH ANY STORMS...ALONG WITH GUSTY WINDS AND HAIL.
GUSTY SOUTHWEST WINDS ARE EXPECTED INTO EARLY THIS EVENING...BEFORE
COLD FRONT PUSHES SOUTH THROUGH THE AREA BETWEEN 00Z AND 06Z
WEDNESDAY. LIGHT WINDS SHIFT TO THE NORTH NORTHEAST BEHIND THE
FRONT...THEN REMAIN NORTH NORTHEAST THROUGH WEDNESDAY. MODERATE
NORTH NORTHEAST WINDS ARE EXPECTED AT THE EASTERN TAF SITES BY
WEDNESDAY AFTERNOON.
MARINE...PATCHY FOG SEEMS TO HAVE MIXED OUT ON WEB CAMERAS AT
SHEBOYGAN AND PORT WASHINGTON...WITH MODERATE SOUTH WINDS MIXING
THIS FOG OUT. GUSTY WINDS AT MARINE OBSERVATION SITES ARE AT SMALL
CRAFT CRITERIA...BUT THESE SHOULD BEGIN TO WEAKEN SHORTLY...SO WILL
NOT ISSUE AN ADVISORY.
SHOULD SEE AT LEAST PATCHY FOG DEVELOP LATER TONIGHT INTO EARLY
WEDNESDAY WITH MOIST AIRMASS OVER THE COOL LAKE WATERS. SOME
POTENTIAL FOR MORE WIDESPREAD FOG DURING THIS TIME.
KEPT CHANCE WORDING FOR SHOWERS AND THUNDERSTORMS THROUGH THIS
EVENING. SOME UNCERTAINTY WITH IF AND HOW WIDESPREAD STORMS WILL
BE...GIVEN WEAK COLD FRONT MOVING THROUGH. SEVERE STORMS WITH STRONG
WINDS AND LARGE HAIL ARE POSSIBLE IF ANY STORMS DO DEVELOP. QUICK
WIND SHIFT TO THE NORTH NORTHEAST IS EXPECTED WITH THE FRONTAL
PASSAGE LATER THIS EVENING.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...MRC
TONIGHT/WEDNESDAY AND AVIATION/MARINE...WOOD
WEDNESDAY NIGHT THROUGH TUESDAY...GEHRING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
620 PM CDT TUE AUG 27 2013
.SHORT TERM...(TONIGHT THROUGH WEDNESDAY NIGHT)
ISSUED AT 325 PM CDT TUE AUG 27 2013
MAIN FORECAST CONCERNS THIS CYCLE...SHRA/TSRA CHANCES AND HEAT INTO
THIS EVENING...FOG POTENTIAL LATER TONIGHT/EARLY WED...TEMPERATURES
THRU THE PERIOD.
18Z DATA ANALYSIS HAD THE LOW/TROUGH/FRONT FROM NORTH OF KGRB TO
NEAR KEAU TO KFSD...MAKING SLOW PROGRESS SOUTH. NORTH OF THIS
FEATURE...LOWER STRATUS CLOUDS COMMON ACROSS NORTHERN WI INTO EAST
CENTRAL MN...WITH TEMPS IN THESE AREAS IN THE 70S TO MID 80S. SOUTH
OF THE TROUGH/FRONT...SKIES WERE AGAIN SUNNY/MOSTLY SUNNY WITH
DEW POINTS IN THE UPPER 60S TO LOWER 70S AND TEMPS QUICKLY WARMING
INTO THE UPPER 80S TO LOWER 90S. DRIER AIR IN THE 925-850MB LAYER
COMBINED WITH DEEPENING MIXING HAVING DOWNWARD PRESSURE ON THE
SFC DEW POINTS TODAY. EARLY AFTERNOON DEW POINTS NEAR TO AS MUCH AS
4F LOWER THAN AT 18Z MON. EARLY AFTERNOON HEAT INDICES IN THIS
AIRMASS WERE IN THE UPPER 80S/90S...STILL MAKING FOR ANOTHER DAY OF
MUGGY/UNCOMFORTABLE CONDITIONS.
27.12Z MODELS INITIALIZED WELL...EXCEPT GFS WHICH LOOKS DISPLACED
WITH ITS SFC DEW POINT ANALYSIS ACROSS THE UPPER MIDWEST. SOLUTIONS
QUITE SIMILAR FOR TONIGHT THRU WED NIGHT...BUT FOR GFS MORE ROBUST
THAN THE OTHERS WITH PW VALUES AND SHRA/TSRA DEVELOPMENT ALONG THE
RETURNING /WARM/ FRONT LATE WED NIGHT. DPROG/DT OF 500MB HGTS AT
27.12Z SHOWED THE MODEL RUNS OF 25.12Z AND 26.12Z VERIFIED VERY WELL
ACROSS NOAM/EASTERN PAC AS FLOW IS DOMINATED BY A LARGE UPPER RIDGE
CENTERED OVER KS/MO. MODELS SHOW A TIGHTENING CONSENSUS TONIGHT/WED
AS THE LARGE BLOCKY RIDGE MOVES LITTLE AND HGTS RISE A BIT OVER THE
DAKOTAS INTO SOUTH-CENTRAL CAN. IMPROVING SIGNAL/CONSENSUS FOR AN
EAST-SOUTHEAST MOVING SHORTWAVE TO BE NEAR THE MAN/ND BORDER BY 12Z
THU. CHECK OF OBS VS. MODEL DATA AT 18Z SHOWED ALL TO BE REASONABLE
WITH THE SFC MASS FIELDS OVER THE CENTRAL CONUS. MOST WERE A BIT
HIGH WITH SFC DEW POINTS OVER THE FCST AREA...AGAIN DUE TO SOME DRIER
925-850MB AIR AND INCREASING MIXING. MODELS DOING A DECENT JOB WITH
THE LOWER STRATUS/925MB MOISTURE NORTH OF THE TROUGH/FRONT AXIS.
MOST IF NOT ALL MODELS TOO FAR WEST/SOUTH WITH 12-18Z PRECIP ACROSS
WI. PER WV IMAGERY MODELS APPEAR REASONABLE WITH THE SHORTWAVE
DETAILS OVER NOAM/EASTERN PAC. NO ONE MODEL FAVORITE AND WITH THE
TIGHTENING CONSENSUS...SIDED WITH A MODEL/ENSEMBLE BLEND. SHORT TERM
FCST CONFIDENCE GOOD THIS CYCLE.
IN THE SHORT TERM...LITTLE IN THE WAY OF MOISTURE TRANSPORT/THETA-E
CONVERGENCE WITH THE TROUGH/FRONT TO SLIDE ACROSS THE AREA THROUGH
THIS EVENING...WITH INDICATIONS OF 850-700MB MOISTURE DIVERGENCE.
DEW POINTS MORE IN THE UPPER 60S/LOW 70S NOT HELPING MATTERS AS FAR
AS INSTABILITY AND ERODING THE CAPPING IN THE 850-700MB LAYER.
CLOSEST TO ERODING THE CAP OVER THE EAST END OF THE FCST AREA AND
WILL LEAVE A SMALL SHRA/TSRA CHANCE THERE INTO EARLY THIS EVENING.
TROUGH SLIPS THRU THIS EVENING WITH A WEAK BUBBLE OF CAN HIGH
PRESSURE BUILDING IN FOR WED. HIGH PROVIDES SOME WEAK LOW LEVEL
COLD ADVECTION AND NORTHEAST SFC-850MB FLOW. 925MB TEMPS IN THE 24C
TO 27C RANGE WED VS. AROUND 30C THE PAST 2-3 DAYS. OF BIGGER CONCERN
IS THE 925MB MOISTURE/STRATUS NORTH OF THE FRONT/TROUGH...WITH GOOD
MODEL SIGNAL FOR THIS MOISTURE/CLOUDS TO ADVECT SOUTHEAST INTO
ACROSS THE AREA LATER TONIGHT THEN LINGER WELL INTO WED. THIS
MOISTURE ALONG WITH COOLING SFC-850MB TEMPS AND THE HIGH DEW
POINTS FAVORABLE FOR FOG IN LOCATIONS THAT DO NOT BECOME COVERED
WITH STRATUS. THESE WOULD HAVE MAJOR IMPACTS ON HIGHS WED...AS IT
IS IN NORTHERN WI TODAY. DUE TO THIS CONCERN...AND HEAT INDICES
STRUGGLING TO REACH HEADLINE CRITERIA...WILL LET HEAT ADVISORY/
WARNING EXPIRE THIS EVENING. SMALL CHANCE A HEAT HEADLINE MAY BE
NEEDED ACROSS THE SOUTH END OF THE FCST AREA WED AFTERNOON...BUT MID
CREW WILL HAVE TO EVALUATE THE CLOUDS/FOG LATER TONIGHT AND MORE
DETAILED IMPACT ON TEMPS WED.
TROUGH/FRONT STARTS TO RETURN NORTHEAST AS A WARM FRONT WED NIGHT.
GFS ABOUT THE ONLY MODEL GENERATING ANY SHRA/TSRA WITH THIS FEATURE
IN/NEAR THE FCST AREA THRU 12Z THU. GFS HAS PW VALUES IN THE 1.5 TO 2
INCH RANGE OVER THE WEST HALF OF THE FCST AREA LATER WED NIGHT...
RESULTING IN 500-1500 J/KG MU CAPE...WHILE BULK OF OTHER MODELS MORE
IN THE 1.5 INCH RANGE AND MU CAPE AROUND 500 J/KG. HOWEVER...LOWER
LEVEL THERMO-DYNAMIC FORCING WEAK IN ALL MODELS. ONLY CARRIED A SMALL
SHRA/TSRA CHANCE OVER THE NORTHWEST CORNER OF THE FCST AREA LATE WED
NIGHT...WHICH BLENDS WITH NEIGHBORING GRIDS FOR NOW. USED A BLEND OF
GUIDANCE LOWS TONIGHT/WED NIGHT. WITH POTENTIAL FOR STRATUS AND
IMPACTS ON HIGHS WED...TRENDED A BIT TOWARD COOLER OF GUIDANCE HIGHS.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 325 PM CDT TUE AUG 27 2013
MAIN FORECAST CONCERNS FOR THE THURSDAY THRU FRI NIGHT PERIOD...
SHRA/TSRA CHANCES WITH THE RETURNING FRONT THU/THU NIGHT THEN NEXT
APPROACHING TROUGH FRI/FRI NIGHT. TEMPERATURES THRU THE PERIOD.
MODELS REMAIN IN REASONABLY GOOD AGREEMENT THU/THU NIGHT AS THE
ND/MAN SHORTWAVE PASSES...THE MID LEVEL RIDGE AXIS IS PUSHED WEST
AND HGTS OVER THE REGION BEGIN TO FALL. NEXT STRONGER SHORTWAVE
HEADED ACROSS SOUTHERN CAN PUSHES THE RIDGE AXIS BACK EAST...INTO
THE UPPER MIDWEST FOR FRI/FRI NIGHT. FCST CONFIDENCE IN THE THU
THRU FRI NIGHT PERIOD IS AVERAGE TO GOOD.
WARM FRONT AND SFC-850MB MOISTURE/CAPE AXIS MOVE EAST/NORTHEAST
ACROSS THE FCST AREA THU/THU NIGHT. HOWEVER THE ND/MAN SHORTWAVE
PROGGED TO PASS NORTH/EAST OF THE FCST AREA WITH LOWER LEVEL THERMO-
DYNAMIC FORCING REMAINING ON THE WEAK SIDE AT LEAST THRU THU INTO
THU EVENING. MODEL SOUNDINGS SHOWING SOME CAPPING IN THE 900-800MB
LAYER AS WELL ON THU. WITH THE FRONT MOVING THRU THE AREA...DID
CONTINUE SOME 20-30 PERCENT SHRA/TSRA CHANCES THU. 925-850MB LOW
LEVEL JET INCREASES THU NIGHT...WITH AN INCREASE OF MOISTURE
TRANSPORT/THETA-E CONVERGENCE INTO THE AREA...ESPECIALLY EAST OF
THE MS RIVER. WITH THE IMPROVING MODEL CONSENSUS...RAISED SHRA/TSRA
CHANCES THU NIGHT...MAINLY NORTHEAST OF I-94. YET ANOTHER SHORTWAVE
DROPS SOUTHEAST INTO/ACROSS THE REGION IN THE NOW NORTHWEST FLOW
ALOFT FRI/FRI NIGHT. THIS DRAGS A BROAD/WEAK SFC LOW AND A 925-700MB
TROUGH EAST/SOUTHEAST ACROSS THE AREA. 20-30 PERCENT SHRA/TSRA
CHANCES FOR MUCH OF THE AREA FRI/FRI NIGHT LOOK REASONABLE AT THIS
TIME. WARM BUBBLE OF AIR PUSHES BACK INTO THE AREA FOR FRI WITH SFC
DEW POINTS IN THE UPPER 60S/LOW 70S. IF DRY WEATHER PREVAILS FRI VS.
THE POTENTIAL OF SCT SHRA/TSRA AND MORE CLOUDS...925MB TEMPS WOULD
SUPPORT HIGHS IN THE LOW-MID 90S WHICH WOULD SEND HEAT INDICES BACK
INTO THE 95-105 RANGE. MAY NEED ANOTHER HEAT ADVISORY CENTERED ON
FRI AFTERNOON. WITH SOME DETAIL UNCERTAINTIES...FAVORED THE MODEL/
ENSEMBLE CONSENSUS OF THU THRU FRI NIGHT HIGHS/LOWS FOR NOW.
FOR SATURDAY THRU TUESDAY /DAYS 4-7/...
MEDIUM RANGE MODEL RUNS OF 27.00Z/27.12Z IN REASONABLE AGREEMENT
SAT/SUN FOR A STRONGER SHORTWAVE TO BE TOPPING THE CENTRAL/WESTERN
NOAM RIDGING SAT THEN DROPPING ACROSS THE WESTERN GREAT LAKES SUN.
SOME STRENGTH/TIMING DIFFERENCES AT DAY 4/5 BUT THIS TO BE EXPECTED.
OVERALL TREND IS STRONGER WITH THIS FEATURE. REASONABLE AGREEMENT
FOR THE PATTERN TO SLOWLY PROGRESS MON/TUE WITH THE MID LEVEL RIDGING
BUILDING BACK EAST TOWARD/INTO THE UPPER MIDWEST BY TUE. ECMWF WITH
THE BETTER OVERALL RUN-TO-RUN CONSISTENCY THRU THE PERIOD. FCST
CONFIDENCE IN THE DAY 4-7 PERIOD IS AVERAGE THIS CYCLE.
DUE TO DIFFERENCES IN TIMING...MODELS PUSH A MDT COLD FRONT SOUTHEAST
ACROSS THE REGION SOMETIME SAT OR SUN. 27.12Z MODEL CONSENSUS BRINGS
THE FRONT THRU LATE SAT/SAT NIGHT...WITH A SECONDARY TROUGH/FRONTAL
PASSAGE SUNDAY. SMALL SHRA/TSRA CHANCES SAT/SUN PER THE MODEL
CONSENSUS REASONABLE AT THIS TIME UNTIL MOISTURE/FRONTAL DETAILS
BECOME CLEARER. BETTER CONSENSUS FOR A MDT TO STRONG...COOLER
CANADIAN HIGH TO SETTLE ACROSS THE WESTERN GREAT LAKES REGION FOR
MON/TUE AS RIDGING ALOFT BUILDS INTO MAN/SASKAT AND TROUGHING DIGS
INTO THE EASTERN GREAT LAKES. LABOR DAY AND TUE POISED TO BE A COUPLE
OF COOLER/MORE COMFORTABLE AND DRY DAYS. OWING TO TIMING DIFFERENCES
STAYED WITH THE MODEL/ENSEMBLE CONSENSUS FOR HIGHS/LOWS FOR SAT THRU
TUE. TREND FOR MON/TUE TEMPS IS NOW NEAR TO A BIT BELOW NORMAL.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 620 PM CDT TUE AUG 27 2013
SEVERAL ISSUES TO DEAL WITH TONIGHT FOR THE 00Z TAFS THAT LENDS A
LOT OF UNCERTAINTY TO THE FORECAST. FIRST IS THE WEAK FRONT NORTH
OF BOTH TAF SITES FROM THE SOUTHERN TWIN CITIES METRO OVER INTO
CENTRAL WISCONSIN AND HOW MUCH OF A SOUTHWARD PUSH IT WILL MAKE
AFTER SUNSET. THE 27.21Z RAP DOES NOT SHOW MUCH OF LOWERING OF THE
UPPER LEVEL HEIGHTS SO THE FRONT WILL BE TRYING TO WORK DEEPER
INTO THE THE UPPER LEVEL RIDGING. THE SURFACE HIGH COMING IN
BEHIND THE FRONT IS NOT VERY STRONG...SO IT WILL BE INTERESTING TO
SEE HOW FAR SOUTH THE FRONT ACTUALLY MAKES IT. THE FRONT IS
ALREADY NOT AS FAR SOUTH AS SOME OF THE MODELS SUGGESTED IT WOULD
BE...SO DELAYED THE TIMING OF THE WIND SHIFT BEHIND THE FRONT
UNTIL LATE THIS EVENING. THEN WHAT HAPPENS BEHIND THE FRONT IN
REGARDS TO FOG AND CLOUDS IS THE THE NEXT ISSUE. OBSERVATIONS
ALREADY SHOWING A VFR DECK FORMING BEHIND THE FRONT OVER NORTHERN
WISCONSIN INTO EASTERN MINNESOTA. THE RAP AND 27.18Z NAM BOTH SHOW
THIS MOISTURE FIELD REMAINING IN PLACE AND COMING SOUTH BEHIND THE
FRONT FOR THE OVERNIGHT HOURS. WITH SOME COOLING...THE CLOUD DECKS
COULD SLIP DOWN TO MVFR AND HAVE INTRODUCED THIS INTO THE KLSE
FORECAST WHILE ONLY SHOWING A SCATTERED CLOUD DECK AT KRST WHICH
COULD BE RIGHT ON THE WESTERN EXTENT OF THE CLOUDS. THE NEXT ISSUE
IS WHETHER FOG WILL FORM OR NOT. LOTS OF DENSE FOG FORMED THIS
MORNING BEHIND THE FRONT OVER NORTHERN MINNESOTA AND
WISCONSIN...BUT THIS WAS AIDED BY ABUNDANT LOW LEVEL MOISTURE FROM
A CONVECTIVE COMPLEX. THIS MOISTURE SOURCE IS NOT GOING TO BE
AVAILABLE HERE AND CONCERNED THAT WHILE THE NAM DOES SHOW
SATURATION AT THE SURFACE OCCURRING...BOTH THE TEMP AND DEW POINT
CONTINUE TO DIMINISH THROUGH THE NIGHT AND CONCERNED THAT WITH THE
TEMP CHASING THE DEW POINT DOWN THAT NOT MUCH FOG WILL FORM AND IT
COULD END UP BEING MORE MVFR VISIBILITIES THAN ANYTHING. FOR
NOW...HAVE THE LEFT THE IFR VISIBILITY IN THE FORECAST AND WILL
MONITOR TRENDS THROUGH THE EVENING FOR THE 06Z TAFS.
&&
.CLIMATE...
ISSUED AT 334 PM CDT MON AUG 26 2013
THE FOLLOWING ARE RECORD HIGHS FOR LA CROSSE AND ROCHESTER
THROUGH LABOR DAY WEEKEND...GIVEN THE HEAT FORECAST. FOR MORE
CLIMATE INFORMATION...SEE OUR WEBSITE AND THE TOP NEWS STORY ON
THE HEAT.
LA CROSSE ROCHESTER
--------- ---------
WED 8/28 97/1955 96/1955
THU 8/29 95/1966 92/2012
FRI 8/30 97/2012 96/1941
SAT 8/31 95/1953 93/1960
SUN 9/1 98/1913 94/1937
MON 9/2 98/1937 94/1929
NORMAL HIGH TEMPERATURES THROUGH THIS PERIOD ARE 78-80 AT LA CROSSE
AND 76-78 AT ROCHESTER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR WIZ017-029-034-
042>044-053>055-061.
EXCESSIVE HEAT WARNING UNTIL MIDNIGHT CDT TONIGHT FOR WIZ032-033-
041.
MN...HEAT ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR MNZ086-087-094-095.
EXCESSIVE HEAT WARNING UNTIL MIDNIGHT CDT TONIGHT FOR MNZ079-088-
096.
IA...HEAT ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR IAZ008>011-018-019-
029-030.
&&
$$
SHORT TERM...RRS
LONG TERM....RRS
AVIATION...04
CLIMATE......WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
334 PM CDT MON AUG 26 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 334 PM CDT MON AUG 26 2013
FORECAST CONCERNS ARE SEVERE THUNDERSTORMS THIS EVENING INTO THE
OVERNIGHT HOURS OVER NORTH CENTRAL WISCONSIN...WITH THE POTENTIAL
FOR DAMAGING WINDS...HEAVY RAINFALL...AND POSSIBLY LARGE HAIL.
ADDITIONAL CONCERNS ARE ON HEAT INDICES THROUGH TUESDAY.
LATEST SURFACE OBSERVATIONS PLACED A WARM FRONT EXTENDING FROM NEAR
MOORHEAD MINNESOTA THEN EXTENDING EAST...JUST NORTH OF THE
INTERSTATE 94 CORRIDOR...THEN RUNNING EAST TO JUST ALONG THE
WISCONSIN HIGHWAY 64 CORRIDOR. WATER VAPOR IMAGERY SHOWED A
SHORTWAVE MOVING EAST ACROSS EAST NORTH DAKOTA AND HEADING INTO
WESTERN MINNESOTA.
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG THE WARM
FRONT THIS EVENING...FIRST OVER WEST CENTRAL MINNESOTA AS THE
SHORTWAVE INTERACTS WITH THE WARM FROM...THEN SPREADING EASTWARD
ALONG THE FRONT THIS EVENING AS THE WAVE PROGRESSES EAST. A VERY
MOIST AIRMASS IN PLACE OVER THE REGION WITH PRECIPITABLE WATER
VALUES RANGING FROM 1.8 TO 2.3...WHICH IS AROUND 200 PERCENT OF
NORMAL. ALSO...WARM CLOUD DEPTHS INCREASE TO 4.5 KM THIS EVENING. IN
ADDITION...850MB MOISTURE TRANSPORT INCREASES INTO THE FRONT THIS
EVENING. THESE FACTORS WILL LEAD TO THE POTENTIAL FOR HEAVY RAINFALL
WHICH COULD PRODUCE FLASH FLOODING. LOCATIONS OVER TAYLOR
COUNTY....ROUGHLY ALONG A LINE EXTENDING FROM JUMP RIVER...TO
MEDFORD...TO GAD...SAW RAINFALL AMOUNTS OF 2 TO ALMOST 3 INCHES
EARLY THIS MORNING. GIVEN THESE RAINFALL AMOUNTS PRECONDITIONING
THESE AREAS...WILL CONTINUE THE FLASH FLOOD WATCH FOR TAYLOR COUNTY
FROM 00Z THIS EVENING THROUGH 12Z TUESDAY MORNING. 0-6 KM BULK SHEAR
VALUES INCREASE TO 30 TO 35 KTS NORTH OF INTERSTATE 90 THIS EVENING
THEN INCREASE FURTHER TO AROUND 45 KTS LATE TONIGHT AS THE SHORTWAVE
MOVES INTO NORTHERN MINNESOTA AND NORTHERN WISCONSIN. THINKING
INITIALLY THE PRIMARY HAZARDS THIS EVENING OVER NORTH CENTRAL
WISCONSIN WILL BE HEAVY RAINFALL AND DAMAGING WINDS. SUPERCELLS LOOK
TO INITIATE OVER SOUTHEAST NORTH DAKOTA LATE THIS AFTERNOON INTO
EARLY THIS EVENING THEN RACE EAST ACROSS NORTH CENTRAL
MINNESOTA...FORMING INTO BOWING STRUCTURES WITH DAMAGING WINDS. THIS
ACTIVITY COULD BUILD SOUTH AS IT APPROACHES WEST CENTRAL
WISCONSIN...POSSIBLY GETTING INTO THE FORECAST AREA AFTER MIDNIGHT.
THINKING MOST OF THIS ACTIVITY SHOULD REMAIN NORTH OF INTERSTATE
90...AND POSSIBLY NORTH OF THE INTERSTATE 94 CORRIDOR. ANOTHER HOT
AND MUGGY DAY IS IN STORE FOR THE AREA ON TUESDAY...BUT IT IS
UNCLEAR HOW FAR SOUTH OUT FLOW BOUNDARIES WOULD GET FROM OVERNIGHT
CONVECTION WHICH WILL HAVE AN IMPACT ON HIGH TEMPERATURES TOMORROW.
IT APPEARS MUCH OF THE FORECAST AREA WILL REMAIN IN THE WARM
SECTOR...WITH HOT SOUTHERLY FLOW PERSISTING UNTIL A WEAK COLD FRONT
MOVES THROUGH LATE IN THE AFTERNOON INTO THE EVENING HOURS. THERE
ISN/T MUCH CONVERGENCE ALONG THE FRONT SO NOT ANTICIPATING
THUNDERSTORM DEVELOPMENT BUT WILL HAVE TO KEEP A CLOSE EYE ON IT.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 334 PM CDT MON AUG 26 2013
HIGH PRESSURE SETTLES INTO THE AREA TUESDAY NIGHT THROUGH EARLY
THURSDAY MORNING PROVIDING SOME RELIEF FROM THE HEAT. HIGHS ON
THURSDAY WILL STILL BE ON THE UNCOMFORTABLE SIDE...CLIMBING INTO
THE UPPER 80S TO LOWER 90S. DEWPOINTS ALSO GRADUALLY FALL WEDNESDAY
AFTERNOON INTO WEDNESDAY EVENING AS NORTHEASTERLY FLOW USHERS IN
SLIGHTLY DRIER AIR. HEAT INDEX VALUES ARE EXPECTED TO CLIMB INTO THE
UPPER 80S TO LOWER 90S ON WEDNESDAY. THE HIGH SHIFTS EAST ON
THURSDAY AS A WARM FRONT PUSHES EAST OUT OF THE NORTHERN PLAINS INTO
THE UPPER MISSISSIPPI RIVER VALLEY. THE FRONT WILL BRING A CHANCE OF
SHOWERS AND THUNDERSTORMS TO THE FORECAST AREA AS IT MOVES THROUGH
THURSDAY INTO THURSDAY NIGHT. THE FRONT THEN STALLS OVER THE REGION
FRIDAY INTO THE WEEKEND AND INTERACTS WITH WEAK SHORTWAVES AS UPPER
RIDGING PUSHES EAST OUT OF THE NORTHERN PLAINS. THERE REMAINS
CONSIDERABLE UNCERTAINTY ON TEMPERATURES THIS WEEKEND THROUGH LABOR
DAY. THE GFS IS SHOWING WARM SOUTHERLY FLOW...WITH HIGHS CLIMBING
WELL INTO THE 90S. ON THE OTHER HAND THE ECMWF SHOWS A TROUGH OVER
THE REGION WITH HIGHS ONLY IN THE 80S ON SATURDAY...THEN FALLING
INTO MID 70S TO LOWER 80S ON SUNDAY. THE GFS WOULD KEEP US IN THE
90S ON SUNDAY...THEN A COLD FRONT FINALLY SLIDES THROUGH ON MONDAY
AND COOLS HIGHS. FRIDAY LOOKS TO BE THE WARMEST DAY...WITH POSSIBLY
HEAT HEADLINES NEEDED AGAIN ALONG AND WEST OF THE MISSISSIPPI RIVER.
WILL HAVE TO KEEP A VERY CLOSE WATCH ON MODEL TRENDS OVER THE NEXT
FEW DAYS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1215 PM CDT MON AUG 26 2013
WITH A SFC FRONT EXPECTED TO STAY NORTH OF KRST/KLSE THROUGH
TONIGHT/WED...THE ENVIRONMENT WILL STAY CAPPED...KEEPING SHRA/TS
TO THE NORTH. VFR CONDITIONS ARE EXPECTED THROUGH WED. COULD SEE
SOME MID/HIGH LEVEL CLOUDS FROM TIME TO TIME...ESPECIALLY LATE
OVERNIGHT/EARLY WED.
FOR WINDS...SOME POTENTIAL FOR HIGHER GUSTS THIS AFTERNOON...BUT NOT
AS MUCH AS PREVIOUS DAYS. SOME CONCERN FOR LLWS AT KLSE/KRST TONIGHT
AS NAM BUFKIT SOUNDINGS SUGGEST WINDS INCREASE TO 40+ KTS BY 1500
FT. GFS AND RAP ARE NOT AS BULLISH THOUGH...ABOUT 10 KTS LESS.
WITHOUT MORE CONSENSUS...CONFIDENCE IS LOWER. WILL KEEP OUT OF THE
TAF FOR NOW...BUT THE POTENTIAL WILL HAVE TO BE MONITORED.
&&
.HYDROLOGY...THROUGH TUESDAY MORNING
ISSUED AT 334 PM CDT MON AUG 26 2013
HEAVY RAIN FELL ACROSS TAYLOR COUNTY EARLY MONDAY
MORNING PRODUCING 2 TO NEARLY 3 INCHES OF RAINFALL. THUNDERSTORMS
ARE POSSIBLE ACROSS THESE SAME AREAS TONIGHT INTO TUESDAY MORNING
AND THEY WILL BE CAPABLE OF PRODUCING VERY HEAVY RAINFALL WITH
PRECIPITABLE WATER VALUES OF 1.8 TO 2.3 INCHES AND WARM CLOUD
DEPTHS OF 4.5 KM. ALSO...850 MOISTURE TRANSPORT FOCUSES INTO A
WARM FRONT LOCATED OVER NORTH CENTRAL WISCONSIN WHICH COULD RESULT
IN REPEATED ROUNDS OF SHOWERS AND THUNDERSTORMS DURING THE
OVERNIGHT HOURS. A FLASH FLOOD WATCH IS IN EFFECT FOR TAYLOR COUNTY
FROM 7PM THIS EVENING THROUGH 7AM TUESDAY.
&&
.CLIMATE...
ISSUED AT 334 PM CDT MON AUG 26 2013
THE FOLLOWING ARE RECORD HIGHS FOR LA CROSSE AND ROCHESTER
THROUGH LABOR DAY WEEKEND...GIVEN THE HEAT FORECAST. FOR MORE
CLIMATE INFORMATION...SEE OUR WEBSITE AND THE TOP NEWS STORY ON
THE HEAT.
LA CROSSE ROCHESTER
--------- ---------
TUE 8/27 95/1973 93/1984
WED 8/28 97/1955 96/1955
THU 8/29 95/1966 92/2012
FRI 8/30 97/2012 96/1941
SAT 8/31 95/1953 93/1960
SUN 9/1 98/1913 94/1937
MON 9/2 98/1937 94/1929
NORMAL HIGH TEMPERATURES THROUGH THIS PERIOD ARE 78-80 AT LA CROSSE
AND 76-78 AT ROCHESTER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR WIZ017-029-
034-042>044-053>055-061.
EXCESSIVE HEAT WARNING UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR
WIZ032-033-041.
FLASH FLOOD WATCH FROM 7 PM CDT THIS EVENING THROUGH TUESDAY
MORNING FOR WIZ017.
MN...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR MNZ086-087-
094-095.
EXCESSIVE HEAT WARNING UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR
MNZ079-088-096.
IA...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR IAZ008>011-
018-019-029-030.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION.....RIECK
HYDROLOGY...WETENKAMP
CLIMATE...WETENKAMP
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 245 PM CDT MON AUG 26 2013
MESO ANALYSIS PAGE INDICATED CAPES OF 2000/3000 J/KG AND SURFACE
BASED CONVECTIVE INHIBITION LESS THAN 50 J/KG ACROSS
NORTH-CENTRAL WISCONSIN. THERE IS A DIFFERENTIAL HEATING
BOUNDARY SET UP ACROSS NORTH CENTRAL INTO NORTHEAST WISCONSIN
THIS AFTERNOON THAT MAY BE A FOCUS FOR CONVECTION LATE THIS
AFTERNOON AND THIS EVENING. TEMPERATURES WERE IN THE LOWER TO
MIDDLE 80S ACROSS THE NORTH AND IN THE LOWER TO MIDDLE 90S SOUTH
OF THE BOUNDARY.
TRYING TO TIME CONVECTIVE COMPLEX TONIGHT AND TUESDAY WILL BE THE
MAIN PROBLEM. SINCE THE HRRR MESOSCALE MODEL DID WELL OVERNIGHT
AND THIS MORNING...WILL FOLLOW THIS MODEL FOR CONVECTIVE TRENDS
TONIGHT INTO TUESDAY MORNING. THE HRRR MODEL INDICATED A CLUSTER
OF SHOWERS AND STORMS WOULD DEVELOP AND MOVE ACROSS THE AREA
LATER THIS AFTERNOON THROUGH MID EVENING...THEN A BREAK IN THE
ACTION UNTIL CONVECTIVE COMPLEX MOVES ACROSS THE AREA AFTER
MIDNIGHT THROUGH MID TUESDAY MORNING. LATEST REGIONAL RADARS INDICATED
CONVECTION WAS TRYING TO FIRE ACROSS WESTERN WISCONSIN AT 1945Z.
AFTER THE CONVECTIVE COMPLEX EXITS THE AREA BY LATE TUESDAY
MORNING...BOUNDARY LURKING NEARBY. STILL SOME UNCERTAINTY
ON HOW CONVECTION WILL EVOLVE TOMORROW AFTERNOON AFTER THE
MORNING CONVECTION. PLENTY OF HEAT AND HUMIDITY AVAILABLE
FOR STRONG OR SEVERE STORMS LATER TOMORROW AFTERNOON. HIGHS
WILL RANGE FROM THE MIDDLE 80S NORTH TO THE LOWER TO MIDDLE 90S
SOUTH.
.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 245 PM CDT MON AUG 26 2013
TEMPERATURES AND PCPN TRENDS ARE THE PRIMARY FCST CONCERNS.
THE COLD FRONT AND WEAK S/W TROF SHOULD GENERATE SCT STG/SVR TSTMS
OVER OUR SE COUNTIES ON TUESDAY EVG...FOLLOWED BY DRY CONDITIONS
FOR THE OVERNIGHT HOURS.
HIGH PRESSURE WILL BRING DRIER AND A LITTLE COOLER WEATHER TO THE
REGION WEDS INTO THU MORNING...BUT RETURN FLOW ON THE NW PERIPHERY
OF THE HIGH MAY BRING PCPN BACK INTO OUR NW COUNTIES BY THURSDAY
AFTERNOON. A WARM AND FAIRLY HUMID AIR MASS SHOULD RETURN TO
THE FORECAST AREA INTO THE WEEKEND...UNTIL A COLD FRONT MOVES
THROUGH ON SUNDAY OR SUNDAY NIGHT. SO...SMALL PCPN CHANCES WILL
CONTINUE DURING THE PERIOD.
MODELS HAVE A BIG DISPARITY IN H8 TEMPS NEXT MONDAY...WITH THE
ECMWF SHOWING A MUCH MORE AMPLIFIED UPPER LEVEL PATTERN AND
MUCH COOLER TEMPS THAN THE GFS/GEFS. NOTICE THAT THE 12Z ECMWF
WAS NOT QUITE AS COLD AS THE PREV RUN...AND IS CLOSER TO THE
ECMWF ENSEMBLE MEAN...SO A COMPROMISE IS IN ORDER. HAVE GONE
WITH SOME MODEST COOLING ON MONDAY...BUT NOTHING AS DRASTIC
AS THE ECMWF SHOWS.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 245 PM CDT MON AUG 26 2013
TRYING TO TIME CONVECTIVE COMPLEXES TONIGHT THROUGH TUESDAY WILL
BE THE MAIN CONCERN. 18Z TAFS TRIED TO DEPICT THE MOST LIKELY
TIMES OF SHOWERS AND STORMS AT THE TAF SITES...BUT SOME ADJUSTMENT
IN TIMING WILL BE NEEDED AS WE GET CLOSER TO THE EVENT. FOLLOWED
THE HRRR MESOSCALE MODEL SINCE IT DID WELL OVERNIGHT AND THIS MORNING.
THIS MODEL IS DEPICTING SCATTERED CONVECTION MOVING OR DEVELOPING
ACROSS THE AREA LATER THIS AFTERNOON INTO MID EVENING...WITH A BREAK
IN THE ACTION FOR AWHILE UNTIL NEXT COMPLEX MOVES ACROSS THE AREA
AFTER MIDNIGHT THROUGH MID MORNING ON TUESDAY. GUSTY WINDS CAN BE
EXPECTED WITH THE STORMS WITH SOME GUSTS OVER 40 KNOTS AND POSSIBLY
50 KNOTS ARE POSSIBLE. A GREAT DEAL OF UNCERTAINTY EXISTS TUESDAY
AFTERNOON WITH BOUNDARY LURKING NEARBY WITH RESPECT TO WIND DIRECTION
AND POSSIBLE SHOWER AND THUNDERSTORM ACTIVITY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....ECKBERG
LONG TERM......KIECKBUSCH
AVIATION.......ECKBERG
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1215 PM CDT MON AUG 26 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 309 AM CDT MON AUG 26 2013
..CURRENTLY AS OF 08Z..
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED TROUGHING OVER
THE PACIFIC NORTHWEST AND EASTERN PACIFIC...AND STRONG SUBTROPICAL
RIDGING OVER KANSAS AND MISSOURI. MONSOONAL MOISTURE AND SHORTWAVES
CONTINUES TO STREAM OUT OF BAJA CALIFORNIA...UP THROUGH THE DAKOTAS
AND INTO THE NORTHERN GREAT LAKES AROUND THE SUBTROPICAL RIDGE. ONE
SUCH SHORTWAVE COMBINED WITH 700MB MOISTURE TRANSPORT SUPPORTING
CONVECTION TRACKING ACROSS FAR NORTHERN WI AND UPPER MICHIGAN.
REGARDING MOISTURE...GOES DERIVED PRECIPITABLE WATER IMAGERY SHOWED
VALUES OF 1.5-2 INCHES FROM EASTERN SOUTH DAKOTA INTO THE NORTHERN
GREAT LAKES. AIRMASS IS ALSO VERY WARM WITH 850MB TEMPS FROM 00Z
RAOBS OF 22-24C ACROSS THE FORECAST AREA AND 24-28C OVER THE
NORTHERN PLAINS. WITH THE FORECAST AREA IN THE WARM SECTOR...SOUTH
OF A WARM FRONT POSITIONED OVER FAR NORTHERN WI...A SOUTHERLY BREEZE
HAS ONLY ALLOWED TEMPS TO FALL INTO THE MID TO UPPER 70S. THIS SAME
SOUTHERLY BREEZE HAS ADVECTED IN SOME LOWER DEWPOINTS...WHICH HAVE
FALLEN INTO THE 60S...LOWEST IN THE SOUTHEAST HALF OF THE AREA. 00Z
DVN SOUNDING REALLY SHOWED THE DRIER AIR COMPARED TO MPX.
..MODEL VERIFICATION..
HAVE INCLUDED THIS SECTION AS IT HAS HIGH IMPORTANCE WITH THE
FORECAST OF HIGH TEMPERATURES AND CONVECTION. LOOKING AT 00Z RAOBS
FOR 925MB TEMPS AND COMPARING TO 25.00Z MODEL GUIDANCE...THE ECMWF
WAS THE BEST WITH ALMOST NO ERROR ACROSS THE NORTHERN PLAINS AND
UPPER MIDWEST. THE GFS WAS GENERALLY 1-2C TOO HIGH. LASTLY...THE
NAM/RAP WERE THE WORST...HAVING ERRORS ON THE ORDER OF 3-6C...
HIGHEST AT MSP. BECAUSE THE NAM/RAP WERE TOO HIGH...IT BROKE THE CAP
AND BROUGHT THE CONVECTION WAY TOO FAR SOUTH.
..HAZARDS..
1. HEAT. TEMPERATURES ARE LIKELY TO BE A FEW DEGREES HIGHER TODAY
AND WITH DEWPOINTS CLIMBING BACK INTO THE LOW 70S...HEAT INDICES
SHOULD TOP OUT IN THE 100-105 RANGE. THE HIGHEST HEAT INDICES LOOK
TO OCCUR FROM LAKE CITY DOWN TO LA CROSSE...AND HAVE UPGRADED THIS
AREA TO AN EXCESSIVE HEAT WARNING.
2. STORMS. SOME SEVERE POTENTIAL AFTER MIDNIGHT TONIGHT...MAINLY
ACROSS TAYLOR/CLARK COUNTIES. HAVE TO WATCH RAINFALL AMOUNTS TOO.
..SYNOPTIC OVERVIEW..
26.00Z MODEL GUIDANCE SUGGESTS THE SUBTROPICAL RIDGING RETROGRADES
JUST SLIGHTLY WESTWARD DURING THE NEXT 24 HOURS. THE MAIN FEATURE OF
FOCUS IS A STRETCHED OUT SHORTWAVE IN THE MONSOONAL FLOW...LOCATED
FROM EASTERN UTAH INTO SOUTH CENTRAL WYOMING. MODELS BRING THIS
SHORTWAVE INTO THE DAKOTAS BY 00Z AND PERHAPS AS FAR EAST AS WESTERN
UPPER MI BY 12Z. THIS SHORTWAVE HELPS TO LIFT A SURFACE LOW SITTING
NEAR THE BLACK HILLS OF SOUTH DAKOTA TO NEAR MINNEAPOLIS BY 12Z TUE.
..DETAILS..
FOCUS FOR POTENTIAL CONVECTION TODAY WILL LIE ON THE LOCATION OF THE
WARM FRONT IN NORTHERN WI. FIRST OFF...THE CURRENT CONVECTION
CROSSING FAR NORTHERN WI AND UPPER MI COULD DROP INTO TAYLOR AND
POSSIBLY CLARK COUNTY BEFORE WEAKENING THIS MORNING. THE OUTFLOW
FROM THE CONVECTION SHOULD HELP PUSH THE FRONT SOUTH TOWARDS I-94
THIS AFTERNOON. THEN...THE NEXT QUESTION IS IF THE AIRMASS IS
CAPPED...WHICH ENTIRELY DEPENDS ON HOW WARM WE GET. THERE SHOULD BE
PLENTY OF SUN TODAY ACROSS THE FORECAST AREA WITH MAYBE A FEW STRAY
CIRRUS CLOUDS. ECMWF 925MB TEMPS ARE PROGGED ABOUT 1-2C HIGHER
COMPARED TO YESTERDAY...THUS ANTICIPATING HIGHS TO BE ABOUT 1-3F
HIGHER... YIELDING READINGS MAINLY IN THE LOW TO MID 90S. A FEW
SPOTS LIKE LSE COULD EVEN HIT THE UPPER 90S. ECMWF ALSO DID VERY
WELL WITH THE DEWPOINTS YESTERDAY AND SUGGESTS THEY SHOULD CLIMB
INTO THE LOW 70S IN THE AFTERNOON...DUE TO EVAPOTRANSPORATION AND
THE HIGHER MOISTURE TO OUR NORTHWEST SLIDING SOUTH. THE FORECAST
HIGHS AND DEWPOINTS WOULD SEEM TO POINT TO POTENTIAL FOR THE CAP TO
BREAK...THUS HAVE INCLUDED 20-40 PERCENT CHANCES ON THE WARM FRONT
FOR THE AFTERNOON. SHOULD STORMS DEVELOP...0-6KM SHEAR IS ONLY 25 KT
AT BEST WITH 0-3KM NEAR 20KT. THIS MEANS THE STORMS WILL PROBABLY BE
UNORGANIZED AND MOST LIKELY JUST HEAVY RAIN MAKERS GIVEN HIGH CAPE
AND NEAR 2 INCH PRECIPITABLE WATERS.
TONIGHT IS A BIT MORE INTERESTING. A CONVECTIVE COMPLEX APPEARS
LIKELY TO DEVELOP IN THE GRAND FORKS AREA IN THE EVENING AHEAD OF
THE SHORTWAVE. THIS CONVECTION...AIDED ALSO BY 700MB MOISTURE
TRANSPORT LIKE THE CONVECTION GOING OVER UPPER MI...SHOULD TRACK
EAST-SOUTHEAST INTO NORTHERN WI. THIS MEANS TAYLOR/CLARK COULD BE
IMPACTED BY THE COMPLEX AFTER MIDNIGHT. ADDITIONAL CONVECTION COULD
FORM ON THE NOSE OF 850MB MOISTURE TRANSPORT NORTH OF I-94 THIS
EVENING AS WELL. CANNOT RULE OUT SOME SEVERE WEATHER...LIKELY IN THE
FORM OF DAMAGING WINDS AND LARGE HAIL...ESPECIALLY AFTER MIDNIGHT
WHEN 0-6 KM SHEAR VALUES APPROACH 30-40 KT. THE REST OF THE AREA
SHOULD STAY MAINLY DRY...CAPPED AND WARM WITH A SOUTHERLY BREEZE
PERSISTING. LOW TEMPERATURES ARE LIKELY TO BE SIMILAR TO NOW GIVEN
SIMILAR CONDITIONS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 309 AM CDT MON AUG 26 2013
..HAZARDS..
1. HEAT...WHICH WILL PERSIST INTO TUESDAY. COLD FRONT COMES THROUGH
TUESDAY NIGHT WHICH SHOULD HELP ADVECT BOTH SOMEWHAT COOLER AND MORE
IMPORTANTLY DRIER AIR INTO THE AREA FOR WEDNESDAY. HEAT LOOKS TO
RETURN DURING LABOR DAY WEEKEND.
2. STORMS. THOSE ON TUESDAY COULD POSE A SEVERE AND HEAVY RAIN
THREAT NORTH OF I-94.
..SYNOPTIC OVERVIEW..
26.00Z MODEL GUIDANCE CONTINUES TO SUGGEST THAT THE SUBTROPICAL HIGH
WILL RETROGRADE WESTWARD THROUGH THE WEEK...ENDING UP IN COLORADO ON
FRIDAY. THIS RETROGRESSION IS IN RESPONSE TO A SERIES OF SHORTWAVE
TROUGHS DROPPING INTO THE MID-ATLANTIC REGION ON THE EAST SIDE OF
THE RIDGE. AS WE HEAD INTO THE WEEKEND...THE SUBTROPICAL RIDGE WILL
SHIFT EAST IN RESPONSE TO WHAT LOOKS TO BE A VERY DEEP TROUGH FOR
THIS TIME OF YEAR COMING INTO THE PACIFIC NORTHWEST. IT SHOULD BE
NOTED THAT THE 26.00Z ECMWF THROWS A MAJOR CURVE BALL TO THE WEEKEND
PLAN...DEVIATING GREATLY FROM ITS PREVIOUS RUN IN SHOWING A TROUGH
DIGGING INTO THE WESTERN GREAT LAKES LATE SUNDAY. THE REASON IS
RELATED TO THIS TROUGH BEING STRONGER AND TRACKING FARTHER SOUTH
COMING OUT OF SOUTHWEST CANADA ON FRIDAY...COMPARED TO ITS PREVIOUS
RUN...THE 26.00Z GFS AND CANADIAN. NOT READY TO FULLY BUY INTO THE
26.00Z ECMWF QUITE YET BEFORE SEEING THE ECMWF ENSEMBLES AND ITS
NEXT RUN.
..DETAILS..
THE SURFACE OVER CENTRAL MN AT 12Z TUESDAY WILL GRADUALLY DROP
SOUTHEAST THROUGH TUESDAY AND TUESDAY NIGHT...IN RESPONSE TO THE
SHORTWAVE AND CONVECTION OVER NORTHERN WI/UPPER MI DROPPING
SOUTHEAST. HAVE KEPT SOME CHANCES ON TUESDAY NORTHEAST OF I-94 FOR
THE CONVECTION DROPPING SOUTHEAST...WHICH COULD BE SEVERE AS WELL.
THE REST OF THE AREA LOOKS CAPPED. TALKING ABOUT THE CAPPING...925MB
TEMPS ARE PROGGED TO REACH ABOUT 28C ON I-94 TO 30C IN NORTHEAST
IOWA. THESE READINGS SHOULD YIELD HIGHS RANGING FROM THE LOW TO
UPPER 90S...WARMEST IN RIVER VALLEYS. THE EXCESSIVE HEAT WARNING MAY
NEED EXPANSION INTO SOME OF NORTHEAST IOWA AND FAR SOUTHWEST WI IF
TEMP/DEWPOINT TRENDS CONTINUE. ALL CONVECTION LOOKS LIKE IT WILL BE
SOUTHEAST OF THE AREA FOR TUESDAY NIGHT...THUS WENT DRY THEN.
DRY CONDITIONS ARE EXPECTED FOR WEDNESDAY AND WEDNESDAY NIGHT AS
HIGH PRESSURE BUILDS OVER WISCONSIN AND MICHIGAN IN THE WAKE OF
TUESDAYS LOW AND COLD FRONTAL PASSAGE. 925MB TEMPS OF 24-26C STILL
SUPPORTS HIGHS IN THE MID 80S TO LOW 90S...THOUGH. DEWPOINTS MAY
STILL BE UP IN THE LOW 70S OVER NORTHEAST IOWA...BUT HEAT INDICES
ARE MORE AROUND 95 VERSUS THE 100-105 AS OF LATE.
THURSDAY THROUGH SATURDAY FEATURE A GRADUAL WARM ADVECTION
PATTERN...WHICH MEANS A RETURN FOR SOME CHANCES OF SHOWERS AND
THUNDERSTORMS. HIGHEST CHANCES ARE FORECAST THURSDAY NIGHT OVER
WISCONSIN WHERE THERE APPEARS TO BE A JUXTAPOSITION OF RIGHT
ENTRANCE REGION FORCING...A POSSIBLE SHORTWAVE MOVING THROUGH...AND
THE LOW LEVEL MOISTURE TRANSPORT. SOME OF THESE CHANCES OF SHOWERS
AND THUNDERSTORMS MAY BE ABLE TO BE BETTER REFINED...IN TERMS OF
DRYING SOME OUT...OVER THE COMING DAYS AS MODELS SETTLE INTO THE
TIMING OF THE WARM ADVECTION. ONCE THE WARM AIR COMES IN...WE WILL
HAVE TO BE CONCERNED WITH HEAT ADVISORIES...AS EVEN THE NEW 26.00Z
ECMWF SHOWS 925MB TEMPS APPROACHING 30C OVER WESTERN PORTIONS OF THE
FORECAST AREA LATE FRIDAY.
SUNDAY AND THE REST OF LABOR DAY WEEKEND FORECAST IS NOW UP IN THE
AIR DUE TO THE NEW 26.00Z ECMWF. PREVIOUSLY AND IN AGREEMENT WITH
THE 26.00Z GFS IT APPEARED MUCH OF THE AREA WOULD BE IN THE WARM
SECTOR...WITH 925MB TEMPS OF 29-32C WHICH COULD ALLOW FOR HIGHS
AROUND 100. IF THE NEW ECMWF IS RIGHT...WE GET A MOSTLY DRY COLD
FRONTAL PASSAGE ON SUNDAY WITH HIGHS MORE IN THE MID TO UPPER 80S.
MONDAY ENDS UP MUCH MUCH COOLER WITH HIGHS MOSTLY IN THE 60S.
COMPARE THIS TO ITS PREVIOUS 4 RUNS SHOWING 94-98 AT LA CROSSE FOR
MONDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1215 PM CDT MON AUG 26 2013
WITH A SFC FRONT EXPECTED TO STAY NORTH OF KRST/KLSE THROUGH
TONIGHT/WED...THE ENVIRONMENT WILL STAY CAPPED...KEEPING SHRA/TS
TO THE NORTH. VFR CONDITIONS ARE EXPECTED THROUGH WED. COULD SEE
SOME MID/HIGH LEVEL CLOUDS FROM TIME TO TIME...ESPECIALLY LATE
OVERNIGHT/EARLY WED.
FOR WINDS...SOME POTENTIAL FOR HIGHER GUSTS THIS AFTERNOON...BUT NOT
AS MUCH AS PREVIOUS DAYS. SOME CONCERN FOR LLWS AT KLSE/KRST TONIGHT
AS NAM BUFKIT SOUNDINGS SUGGEST WINDS INCREASE TO 40+ KTS BY 1500
FT. GFS AND RAP ARE NOT AS BULLISH THOUGH...ABOUT 10 KTS LESS.
WITHOUT MORE CONSENSUS...CONFIDENCE IS LOWER. WILL KEEP OUT OF THE
TAF FOR NOW...BUT THE POTENTIAL WILL HAVE TO BE MONITORED.
&&
.CLIMATE...
ISSUED AT 346 PM CDT SUN AUG 25 2013
THE FOLLOWING ARE RECORD HIGHS FOR LA CROSSE AND ROCHESTER
THROUGH LABOR DAY WEEKEND...GIVEN THE HEAT FORECAST. FOR MORE
CLIMATE INFORMATION...SEE OUR WEBSITE AND THE TOP NEWS STORY ON
THE HEAT.
LA CROSSE ROCHESTER
--------- ---------
MON 8/26 96/1991 95/1955
TUE 8/27 95/1973 93/1984
WED 8/28 97/1955 96/1955
THU 8/29 95/1966 92/2012
FRI 8/30 97/2012 96/1941
SAT 8/31 95/1953 93/1960
SUN 9/1 98/1913 94/1937
MON 9/2 98/1937 94/1929
NORMAL HIGH TEMPERATURES THROUGH THIS PERIOD ARE 78-80 AT LA CROSSE
AND 76-78 AT ROCHESTER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR WIZ017-029-
034-042>044-053>055-061.
EXCESSIVE HEAT WARNING UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR
WIZ032-033-041.
FLASH FLOOD WATCH FROM 7 PM CDT THIS EVENING THROUGH TUESDAY
MORNING FOR WIZ017.
MN...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR MNZ086-087-
094-095.
EXCESSIVE HEAT WARNING UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR
MNZ079-088-096.
IA...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR IAZ008>011-
018-019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM....AJ
AVIATION.....RIECK
CLIMATE......WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1145 AM CDT MON AUG 26 2013
.UPDATED...
ISSUED AT 1145 AM CDT MON AUG 26 2013
RAINFALL UP TO 3 INCHES FELL ACROSS PARTS OF TAYLOR COUNTY THIS
MORNING. WITH THE SFC BOUNDARY WAVERING ACROSS THE AREA THROUGH THE
AFTERNOON/NIGHT. SOME STORMS COULD FIRE ALONG THIS BOUNDARY...JUST
NORTH OF THE LOW LEVEL CAPPING INVERSION...LATER THIS AFTERNOON.
THEN TONIGHT...A THUNDERSTORM COMPLEX IS EXPECTED TO ROLL
EAST/SOUTHEAST FORM THE NORTHERN PLAINS TO ACROSS NORTHERN WI. WITH
WARM CLOUD DEPTHS AROUND 4000 M AND PWS UPWARDS OF 200 PERCENT...ANY
STORM WILL BE CAPABLE OF HEAVY DOWNPOURS. TRAINING STORMS ARE
LIKELY. WITH THIS IN MIND...WILL ISSUE A FLASH FLOOD WATCH FOR
TAYLOR COUNTRY TONIGHT. STILL SOME UNCERTAINTY WITH THE EXACT
TRACK OF THIS MCS TONIGHT...IT COULD GO NORTH OF THE AREA. BUT
ENOUGH OF A THREAT WHERE A WATCH IS WARRANTED.
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 309 AM CDT MON AUG 26 2013
..CURRENTLY AS OF 08Z..
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED TROUGHING OVER
THE PACIFIC NORTHWEST AND EASTERN PACIFIC...AND STRONG SUBTROPICAL
RIDGING OVER KANSAS AND MISSOURI. MONSOONAL MOISTURE AND SHORTWAVES
CONTINUES TO STREAM OUT OF BAJA CALIFORNIA...UP THROUGH THE DAKOTAS
AND INTO THE NORTHERN GREAT LAKES AROUND THE SUBTROPICAL RIDGE. ONE
SUCH SHORTWAVE COMBINED WITH 700MB MOISTURE TRANSPORT SUPPORTING
CONVECTION TRACKING ACROSS FAR NORTHERN WI AND UPPER MICHIGAN.
REGARDING MOISTURE...GOES DERIVED PRECIPITABLE WATER IMAGERY SHOWED
VALUES OF 1.5-2 INCHES FROM EASTERN SOUTH DAKOTA INTO THE NORTHERN
GREAT LAKES. AIRMASS IS ALSO VERY WARM WITH 850MB TEMPS FROM 00Z
RAOBS OF 22-24C ACROSS THE FORECAST AREA AND 24-28C OVER THE
NORTHERN PLAINS. WITH THE FORECAST AREA IN THE WARM SECTOR...SOUTH
OF A WARM FRONT POSITIONED OVER FAR NORTHERN WI...A SOUTHERLY BREEZE
HAS ONLY ALLOWED TEMPS TO FALL INTO THE MID TO UPPER 70S. THIS SAME
SOUTHERLY BREEZE HAS ADVECTED IN SOME LOWER DEWPOINTS...WHICH HAVE
FALLEN INTO THE 60S...LOWEST IN THE SOUTHEAST HALF OF THE AREA. 00Z
DVN SOUNDING REALLY SHOWED THE DRIER AIR COMPARED TO MPX.
..MODEL VERIFICATION..
HAVE INCLUDED THIS SECTION AS IT HAS HIGH IMPORTANCE WITH THE
FORECAST OF HIGH TEMPERATURES AND CONVECTION. LOOKING AT 00Z RAOBS
FOR 925MB TEMPS AND COMPARING TO 25.00Z MODEL GUIDANCE...THE ECMWF
WAS THE BEST WITH ALMOST NO ERROR ACROSS THE NORTHERN PLAINS AND
UPPER MIDWEST. THE GFS WAS GENERALLY 1-2C TOO HIGH. LASTLY...THE
NAM/RAP WERE THE WORST...HAVING ERRORS ON THE ORDER OF 3-6C...
HIGHEST AT MSP. BECAUSE THE NAM/RAP WERE TOO HIGH...IT BROKE THE CAP
AND BROUGHT THE CONVECTION WAY TOO FAR SOUTH.
..HAZARDS..
1. HEAT. TEMPERATURES ARE LIKELY TO BE A FEW DEGREES HIGHER TODAY
AND WITH DEWPOINTS CLIMBING BACK INTO THE LOW 70S...HEAT INDICES
SHOULD TOP OUT IN THE 100-105 RANGE. THE HIGHEST HEAT INDICES LOOK
TO OCCUR FROM LAKE CITY DOWN TO LA CROSSE...AND HAVE UPGRADED THIS
AREA TO AN EXCESSIVE HEAT WARNING.
2. STORMS. SOME SEVERE POTENTIAL AFTER MIDNIGHT TONIGHT...MAINLY
ACROSS TAYLOR/CLARK COUNTIES. HAVE TO WATCH RAINFALL AMOUNTS TOO.
..SYNOPTIC OVERVIEW..
26.00Z MODEL GUIDANCE SUGGESTS THE SUBTROPICAL RIDGING RETROGRADES
JUST SLIGHTLY WESTWARD DURING THE NEXT 24 HOURS. THE MAIN FEATURE OF
FOCUS IS A STRETCHED OUT SHORTWAVE IN THE MONSOONAL FLOW...LOCATED
FROM EASTERN UTAH INTO SOUTH CENTRAL WYOMING. MODELS BRING THIS
SHORTWAVE INTO THE DAKOTAS BY 00Z AND PERHAPS AS FAR EAST AS WESTERN
UPPER MI BY 12Z. THIS SHORTWAVE HELPS TO LIFT A SURFACE LOW SITTING
NEAR THE BLACK HILLS OF SOUTH DAKOTA TO NEAR MINNEAPOLIS BY 12Z TUE.
..DETAILS..
FOCUS FOR POTENTIAL CONVECTION TODAY WILL LIE ON THE LOCATION OF THE
WARM FRONT IN NORTHERN WI. FIRST OFF...THE CURRENT CONVECTION
CROSSING FAR NORTHERN WI AND UPPER MI COULD DROP INTO TAYLOR AND
POSSIBLY CLARK COUNTY BEFORE WEAKENING THIS MORNING. THE OUTFLOW
FROM THE CONVECTION SHOULD HELP PUSH THE FRONT SOUTH TOWARDS I-94
THIS AFTERNOON. THEN...THE NEXT QUESTION IS IF THE AIRMASS IS
CAPPED...WHICH ENTIRELY DEPENDS ON HOW WARM WE GET. THERE SHOULD BE
PLENTY OF SUN TODAY ACROSS THE FORECAST AREA WITH MAYBE A FEW STRAY
CIRRUS CLOUDS. ECMWF 925MB TEMPS ARE PROGGED ABOUT 1-2C HIGHER
COMPARED TO YESTERDAY...THUS ANTICIPATING HIGHS TO BE ABOUT 1-3F
HIGHER... YIELDING READINGS MAINLY IN THE LOW TO MID 90S. A FEW
SPOTS LIKE LSE COULD EVEN HIT THE UPPER 90S. ECMWF ALSO DID VERY
WELL WITH THE DEWPOINTS YESTERDAY AND SUGGESTS THEY SHOULD CLIMB
INTO THE LOW 70S IN THE AFTERNOON...DUE TO EVAPOTRANSPORATION AND
THE HIGHER MOISTURE TO OUR NORTHWEST SLIDING SOUTH. THE FORECAST
HIGHS AND DEWPOINTS WOULD SEEM TO POINT TO POTENTIAL FOR THE CAP TO
BREAK...THUS HAVE INCLUDED 20-40 PERCENT CHANCES ON THE WARM FRONT
FOR THE AFTERNOON. SHOULD STORMS DEVELOP...0-6KM SHEAR IS ONLY 25 KT
AT BEST WITH 0-3KM NEAR 20KT. THIS MEANS THE STORMS WILL PROBABLY BE
UNORGANIZED AND MOST LIKELY JUST HEAVY RAIN MAKERS GIVEN HIGH CAPE
AND NEAR 2 INCH PRECIPITABLE WATERS.
TONIGHT IS A BIT MORE INTERESTING. A CONVECTIVE COMPLEX APPEARS
LIKELY TO DEVELOP IN THE GRAND FORKS AREA IN THE EVENING AHEAD OF
THE SHORTWAVE. THIS CONVECTION...AIDED ALSO BY 700MB MOISTURE
TRANSPORT LIKE THE CONVECTION GOING OVER UPPER MI...SHOULD TRACK
EAST-SOUTHEAST INTO NORTHERN WI. THIS MEANS TAYLOR/CLARK COULD BE
IMPACTED BY THE COMPLEX AFTER MIDNIGHT. ADDITIONAL CONVECTION COULD
FORM ON THE NOSE OF 850MB MOISTURE TRANSPORT NORTH OF I-94 THIS
EVENING AS WELL. CANNOT RULE OUT SOME SEVERE WEATHER...LIKELY IN THE
FORM OF DAMAGING WINDS AND LARGE HAIL...ESPECIALLY AFTER MIDNIGHT
WHEN 0-6 KM SHEAR VALUES APPROACH 30-40 KT. THE REST OF THE AREA
SHOULD STAY MAINLY DRY...CAPPED AND WARM WITH A SOUTHERLY BREEZE
PERSISTING. LOW TEMPERATURES ARE LIKELY TO BE SIMILAR TO NOW GIVEN
SIMILAR CONDITIONS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 309 AM CDT MON AUG 26 2013
..HAZARDS..
1. HEAT...WHICH WILL PERSIST INTO TUESDAY. COLD FRONT COMES THROUGH
TUESDAY NIGHT WHICH SHOULD HELP ADVECT BOTH SOMEWHAT COOLER AND MORE
IMPORTANTLY DRIER AIR INTO THE AREA FOR WEDNESDAY. HEAT LOOKS TO
RETURN DURING LABOR DAY WEEKEND.
2. STORMS. THOSE ON TUESDAY COULD POSE A SEVERE AND HEAVY RAIN
THREAT NORTH OF I-94.
..SYNOPTIC OVERVIEW..
26.00Z MODEL GUIDANCE CONTINUES TO SUGGEST THAT THE SUBTROPICAL HIGH
WILL RETROGRADE WESTWARD THROUGH THE WEEK...ENDING UP IN COLORADO ON
FRIDAY. THIS RETROGRESSION IS IN RESPONSE TO A SERIES OF SHORTWAVE
TROUGHS DROPPING INTO THE MID-ATLANTIC REGION ON THE EAST SIDE OF
THE RIDGE. AS WE HEAD INTO THE WEEKEND...THE SUBTROPICAL RIDGE WILL
SHIFT EAST IN RESPONSE TO WHAT LOOKS TO BE A VERY DEEP TROUGH FOR
THIS TIME OF YEAR COMING INTO THE PACIFIC NORTHWEST. IT SHOULD BE
NOTED THAT THE 26.00Z ECMWF THROWS A MAJOR CURVE BALL TO THE WEEKEND
PLAN...DEVIATING GREATLY FROM ITS PREVIOUS RUN IN SHOWING A TROUGH
DIGGING INTO THE WESTERN GREAT LAKES LATE SUNDAY. THE REASON IS
RELATED TO THIS TROUGH BEING STRONGER AND TRACKING FARTHER SOUTH
COMING OUT OF SOUTHWEST CANADA ON FRIDAY...COMPARED TO ITS PREVIOUS
RUN...THE 26.00Z GFS AND CANADIAN. NOT READY TO FULLY BUY INTO THE
26.00Z ECMWF QUITE YET BEFORE SEEING THE ECMWF ENSEMBLES AND ITS
NEXT RUN.
..DETAILS..
THE SURFACE OVER CENTRAL MN AT 12Z TUESDAY WILL GRADUALLY DROP
SOUTHEAST THROUGH TUESDAY AND TUESDAY NIGHT...IN RESPONSE TO THE
SHORTWAVE AND CONVECTION OVER NORTHERN WI/UPPER MI DROPPING
SOUTHEAST. HAVE KEPT SOME CHANCES ON TUESDAY NORTHEAST OF I-94 FOR
THE CONVECTION DROPPING SOUTHEAST...WHICH COULD BE SEVERE AS WELL.
THE REST OF THE AREA LOOKS CAPPED. TALKING ABOUT THE CAPPING...925MB
TEMPS ARE PROGGED TO REACH ABOUT 28C ON I-94 TO 30C IN NORTHEAST
IOWA. THESE READINGS SHOULD YIELD HIGHS RANGING FROM THE LOW TO
UPPER 90S...WARMEST IN RIVER VALLEYS. THE EXCESSIVE HEAT WARNING MAY
NEED EXPANSION INTO SOME OF NORTHEAST IOWA AND FAR SOUTHWEST WI IF
TEMP/DEWPOINT TRENDS CONTINUE. ALL CONVECTION LOOKS LIKE IT WILL BE
SOUTHEAST OF THE AREA FOR TUESDAY NIGHT...THUS WENT DRY THEN.
DRY CONDITIONS ARE EXPECTED FOR WEDNESDAY AND WEDNESDAY NIGHT AS
HIGH PRESSURE BUILDS OVER WISCONSIN AND MICHIGAN IN THE WAKE OF
TUESDAYS LOW AND COLD FRONTAL PASSAGE. 925MB TEMPS OF 24-26C STILL
SUPPORTS HIGHS IN THE MID 80S TO LOW 90S...THOUGH. DEWPOINTS MAY
STILL BE UP IN THE LOW 70S OVER NORTHEAST IOWA...BUT HEAT INDICES
ARE MORE AROUND 95 VERSUS THE 100-105 AS OF LATE.
THURSDAY THROUGH SATURDAY FEATURE A GRADUAL WARM ADVECTION
PATTERN...WHICH MEANS A RETURN FOR SOME CHANCES OF SHOWERS AND
THUNDERSTORMS. HIGHEST CHANCES ARE FORECAST THURSDAY NIGHT OVER
WISCONSIN WHERE THERE APPEARS TO BE A JUXTAPOSITION OF RIGHT
ENTRANCE REGION FORCING...A POSSIBLE SHORTWAVE MOVING THROUGH...AND
THE LOW LEVEL MOISTURE TRANSPORT. SOME OF THESE CHANCES OF SHOWERS
AND THUNDERSTORMS MAY BE ABLE TO BE BETTER REFINED...IN TERMS OF
DRYING SOME OUT...OVER THE COMING DAYS AS MODELS SETTLE INTO THE
TIMING OF THE WARM ADVECTION. ONCE THE WARM AIR COMES IN...WE WILL
HAVE TO BE CONCERNED WITH HEAT ADVISORIES...AS EVEN THE NEW 26.00Z
ECMWF SHOWS 925MB TEMPS APPROACHING 30C OVER WESTERN PORTIONS OF THE
FORECAST AREA LATE FRIDAY.
SUNDAY AND THE REST OF LABOR DAY WEEKEND FORECAST IS NOW UP IN THE
AIR DUE TO THE NEW 26.00Z ECMWF. PREVIOUSLY AND IN AGREEMENT WITH
THE 26.00Z GFS IT APPEARED MUCH OF THE AREA WOULD BE IN THE WARM
SECTOR...WITH 925MB TEMPS OF 29-32C WHICH COULD ALLOW FOR HIGHS
AROUND 100. IF THE NEW ECMWF IS RIGHT...WE GET A MOSTLY DRY COLD
FRONTAL PASSAGE ON SUNDAY WITH HIGHS MORE IN THE MID TO UPPER 80S.
MONDAY ENDS UP MUCH MUCH COOLER WITH HIGHS MOSTLY IN THE 60S.
COMPARE THIS TO ITS PREVIOUS 4 RUNS SHOWING 94-98 AT LA CROSSE FOR
MONDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 640 AM CDT MON AUG 26 2013
EXPECT THE LOW LEVEL WIND SHEAR AT KLSE TO RAPIDLY DISSIPATE BY
26.14Z AS THE LOW LEVEL JET AND PRESSURE GRADIENT WEAKENS...AND
THE NOCTURNAL INVERSION DISSIPATES THROUGH DIURNAL MIXING.
FOR TODAY...EXPECT ONLY SCATTERED 15K FOOT CLOUDS. WINDS WILL GUST
FROM SOUTHWEST INTO THE 15 TO 25 KNOT RANGE.
AFTER 27.07Z...THERE IS CONCERN THAT LOW LEVEL WIND SHEAR WILL
DEVELOP AT KLSE AS THE WINDS DROP TO LESS THAN 10 KNOTS BELOW THE
NOCTURNAL INVERSION AND THE LOW LEVEL JET STRENGTHENS ALOFT. THE
GFS HAS THIS JET CLIMBING INTO THE 30 TO 35 KNOT RANGE. MEANWHILE
THE NAM/WRF HAS THIS JET STRENGTHENING INTO THE 40 TO 45 KNOT
RANGE. DUE TO THE UNCERTAINTY OF THE STRENGTH OF THIS JET...HELD
OFF MENTIONING IT.
&&
.CLIMATE...
ISSUED AT 346 PM CDT SUN AUG 25 2013
THE FOLLOWING ARE RECORD HIGHS FOR LA CROSSE AND ROCHESTER
THROUGH LABOR DAY WEEKEND...GIVEN THE HEAT FORECAST. FOR MORE
CLIMATE INFORMATION...SEE OUR WEBSITE AND THE TOP NEWS STORY ON
THE HEAT.
LA CROSSE ROCHESTER
--------- ---------
MON 8/26 96/1991 95/1955
TUE 8/27 95/1973 93/1984
WED 8/28 97/1955 96/1955
THU 8/29 95/1966 92/2012
FRI 8/30 97/2012 96/1941
SAT 8/31 95/1953 93/1960
SUN 9/1 98/1913 94/1937
MON 9/2 98/1937 94/1929
NORMAL HIGH TEMPERATURES THROUGH THIS PERIOD ARE 78-80 AT LA CROSSE
AND 76-78 AT ROCHESTER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR WIZ017-029-
034-042>044-053>055-061.
EXCESSIVE HEAT WARNING UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR
WIZ032-033-041.
FLASH FLOOD WATCH FROM 7 PM CDT THIS EVENING THROUGH TUESDAY
MORNING FOR WIZ017.
MN...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR MNZ086-087-
094-095.
EXCESSIVE HEAT WARNING UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR
MNZ079-088-096.
IA...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR IAZ008>011-
018-019-029-030.
&&
$$
UPDATE.......RIECK
SHORT TERM...AJ
LONG TERM....AJ
AVIATION.....BOYNE
CLIMATE......WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
640 AM CDT MON AUG 26 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 309 AM CDT MON AUG 26 2013
..CURRENTLY AS OF 08Z..
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED TROUGHING OVER
THE PACIFIC NORTHWEST AND EASTERN PACIFIC...AND STRONG SUBTROPICAL
RIDGING OVER KANSAS AND MISSOURI. MONSOONAL MOISTURE AND SHORTWAVES
CONTINUES TO STREAM OUT OF BAJA CALIFORNIA...UP THROUGH THE DAKOTAS
AND INTO THE NORTHERN GREAT LAKES AROUND THE SUBTROPICAL RIDGE. ONE
SUCH SHORTWAVE COMBINED WITH 700MB MOISTURE TRANSPORT SUPPORTING
CONVECTION TRACKING ACROSS FAR NORTHERN WI AND UPPER MICHIGAN.
REGARDING MOISTURE...GOES DERIVED PRECIPITABLE WATER IMAGERY SHOWED
VALUES OF 1.5-2 INCHES FROM EASTERN SOUTH DAKOTA INTO THE NORTHERN
GREAT LAKES. AIRMASS IS ALSO VERY WARM WITH 850MB TEMPS FROM 00Z
RAOBS OF 22-24C ACROSS THE FORECAST AREA AND 24-28C OVER THE
NORTHERN PLAINS. WITH THE FORECAST AREA IN THE WARM SECTOR...SOUTH
OF A WARM FRONT POSITIONED OVER FAR NORTHERN WI...A SOUTHERLY BREEZE
HAS ONLY ALLOWED TEMPS TO FALL INTO THE MID TO UPPER 70S. THIS SAME
SOUTHERLY BREEZE HAS ADVECTED IN SOME LOWER DEWPOINTS...WHICH HAVE
FALLEN INTO THE 60S...LOWEST IN THE SOUTHEAST HALF OF THE AREA. 00Z
DVN SOUNDING REALLY SHOWED THE DRIER AIR COMPARED TO MPX.
..MODEL VERIFICATION..
HAVE INCLUDED THIS SECTION AS IT HAS HIGH IMPORTANCE WITH THE
FORECAST OF HIGH TEMPERATURES AND CONVECTION. LOOKING AT 00Z RAOBS
FOR 925MB TEMPS AND COMPARING TO 25.00Z MODEL GUIDANCE...THE ECMWF
WAS THE BEST WITH ALMOST NO ERROR ACROSS THE NORTHERN PLAINS AND
UPPER MIDWEST. THE GFS WAS GENERALLY 1-2C TOO HIGH. LASTLY...THE
NAM/RAP WERE THE WORST...HAVING ERRORS ON THE ORDER OF 3-6C...
HIGHEST AT MSP. BECAUSE THE NAM/RAP WERE TOO HIGH...IT BROKE THE CAP
AND BROUGHT THE CONVECTION WAY TOO FAR SOUTH.
..HAZARDS..
1. HEAT. TEMPERATURES ARE LIKELY TO BE A FEW DEGREES HIGHER TODAY
AND WITH DEWPOINTS CLIMBING BACK INTO THE LOW 70S...HEAT INDICES
SHOULD TOP OUT IN THE 100-105 RANGE. THE HIGHEST HEAT INDICES LOOK
TO OCCUR FROM LAKE CITY DOWN TO LA CROSSE...AND HAVE UPGRADED THIS
AREA TO AN EXCESSIVE HEAT WARNING.
2. STORMS. SOME SEVERE POTENTIAL AFTER MIDNIGHT TONIGHT...MAINLY
ACROSS TAYLOR/CLARK COUNTIES. HAVE TO WATCH RAINFALL AMOUNTS TOO.
..SYNOPTIC OVERVIEW..
26.00Z MODEL GUIDANCE SUGGESTS THE SUBTROPICAL RIDGING RETROGRADES
JUST SLIGHTLY WESTWARD DURING THE NEXT 24 HOURS. THE MAIN FEATURE OF
FOCUS IS A STRETCHED OUT SHORTWAVE IN THE MONSOONAL FLOW...LOCATED
FROM EASTERN UTAH INTO SOUTH CENTRAL WYOMING. MODELS BRING THIS
SHORTWAVE INTO THE DAKOTAS BY 00Z AND PERHAPS AS FAR EAST AS WESTERN
UPPER MI BY 12Z. THIS SHORTWAVE HELPS TO LIFT A SURFACE LOW SITTING
NEAR THE BLACK HILLS OF SOUTH DAKOTA TO NEAR MINNEAPOLIS BY 12Z TUE.
..DETAILS..
FOCUS FOR POTENTIAL CONVECTION TODAY WILL LIE ON THE LOCATION OF THE
WARM FRONT IN NORTHERN WI. FIRST OFF...THE CURRENT CONVECTION
CROSSING FAR NORTHERN WI AND UPPER MI COULD DROP INTO TAYLOR AND
POSSIBLY CLARK COUNTY BEFORE WEAKENING THIS MORNING. THE OUTFLOW
FROM THE CONVECTION SHOULD HELP PUSH THE FRONT SOUTH TOWARDS I-94
THIS AFTERNOON. THEN...THE NEXT QUESTION IS IF THE AIRMASS IS
CAPPED...WHICH ENTIRELY DEPENDS ON HOW WARM WE GET. THERE SHOULD BE
PLENTY OF SUN TODAY ACROSS THE FORECAST AREA WITH MAYBE A FEW STRAY
CIRRUS CLOUDS. ECMWF 925MB TEMPS ARE PROGGED ABOUT 1-2C HIGHER
COMPARED TO YESTERDAY...THUS ANTICIPATING HIGHS TO BE ABOUT 1-3F
HIGHER... YIELDING READINGS MAINLY IN THE LOW TO MID 90S. A FEW
SPOTS LIKE LSE COULD EVEN HIT THE UPPER 90S. ECMWF ALSO DID VERY
WELL WITH THE DEWPOINTS YESTERDAY AND SUGGESTS THEY SHOULD CLIMB
INTO THE LOW 70S IN THE AFTERNOON...DUE TO EVAPOTRANSPORATION AND
THE HIGHER MOISTURE TO OUR NORTHWEST SLIDING SOUTH. THE FORECAST
HIGHS AND DEWPOINTS WOULD SEEM TO POINT TO POTENTIAL FOR THE CAP TO
BREAK...THUS HAVE INCLUDED 20-40 PERCENT CHANCES ON THE WARM FRONT
FOR THE AFTERNOON. SHOULD STORMS DEVELOP...0-6KM SHEAR IS ONLY 25 KT
AT BEST WITH 0-3KM NEAR 20KT. THIS MEANS THE STORMS WILL PROBABLY BE
UNORGANIZED AND MOST LIKELY JUST HEAVY RAIN MAKERS GIVEN HIGH CAPE
AND NEAR 2 INCH PRECIPITABLE WATERS.
TONIGHT IS A BIT MORE INTERESTING. A CONVECTIVE COMPLEX APPEARS
LIKELY TO DEVELOP IN THE GRAND FORKS AREA IN THE EVENING AHEAD OF
THE SHORTWAVE. THIS CONVECTION...AIDED ALSO BY 700MB MOISTURE
TRANSPORT LIKE THE CONVECTION GOING OVER UPPER MI...SHOULD TRACK
EAST-SOUTHEAST INTO NORTHERN WI. THIS MEANS TAYLOR/CLARK COULD BE
IMPACTED BY THE COMPLEX AFTER MIDNIGHT. ADDITIONAL CONVECTION COULD
FORM ON THE NOSE OF 850MB MOISTURE TRANSPORT NORTH OF I-94 THIS
EVENING AS WELL. CANNOT RULE OUT SOME SEVERE WEATHER...LIKELY IN THE
FORM OF DAMAGING WINDS AND LARGE HAIL...ESPECIALLY AFTER MIDNIGHT
WHEN 0-6 KM SHEAR VALUES APPROACH 30-40 KT. THE REST OF THE AREA
SHOULD STAY MAINLY DRY...CAPPED AND WARM WITH A SOUTHERLY BREEZE
PERSISTING. LOW TEMPERATURES ARE LIKELY TO BE SIMILAR TO NOW GIVEN
SIMILAR CONDITIONS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 309 AM CDT MON AUG 26 2013
..HAZARDS..
1. HEAT...WHICH WILL PERSIST INTO TUESDAY. COLD FRONT COMES THROUGH
TUESDAY NIGHT WHICH SHOULD HELP ADVECT BOTH SOMEWHAT COOLER AND MORE
IMPORTANTLY DRIER AIR INTO THE AREA FOR WEDNESDAY. HEAT LOOKS TO
RETURN DURING LABOR DAY WEEKEND.
2. STORMS. THOSE ON TUESDAY COULD POSE A SEVERE AND HEAVY RAIN
THREAT NORTH OF I-94.
..SYNOPTIC OVERVIEW..
26.00Z MODEL GUIDANCE CONTINUES TO SUGGEST THAT THE SUBTROPICAL HIGH
WILL RETROGRADE WESTWARD THROUGH THE WEEK...ENDING UP IN COLORADO ON
FRIDAY. THIS RETROGRESSION IS IN RESPONSE TO A SERIES OF SHORTWAVE
TROUGHS DROPPING INTO THE MID-ATLANTIC REGION ON THE EAST SIDE OF
THE RIDGE. AS WE HEAD INTO THE WEEKEND...THE SUBTROPICAL RIDGE WILL
SHIFT EAST IN RESPONSE TO WHAT LOOKS TO BE A VERY DEEP TROUGH FOR
THIS TIME OF YEAR COMING INTO THE PACIFIC NORTHWEST. IT SHOULD BE
NOTED THAT THE 26.00Z ECMWF THROWS A MAJOR CURVE BALL TO THE WEEKEND
PLAN...DEVIATING GREATLY FROM ITS PREVIOUS RUN IN SHOWING A TROUGH
DIGGING INTO THE WESTERN GREAT LAKES LATE SUNDAY. THE REASON IS
RELATED TO THIS TROUGH BEING STRONGER AND TRACKING FARTHER SOUTH
COMING OUT OF SOUTHWEST CANADA ON FRIDAY...COMPARED TO ITS PREVIOUS
RUN...THE 26.00Z GFS AND CANADIAN. NOT READY TO FULLY BUY INTO THE
26.00Z ECMWF QUITE YET BEFORE SEEING THE ECMWF ENSEMBLES AND ITS
NEXT RUN.
..DETAILS..
THE SURFACE OVER CENTRAL MN AT 12Z TUESDAY WILL GRADUALLY DROP
SOUTHEAST THROUGH TUESDAY AND TUESDAY NIGHT...IN RESPONSE TO THE
SHORTWAVE AND CONVECTION OVER NORTHERN WI/UPPER MI DROPPING
SOUTHEAST. HAVE KEPT SOME CHANCES ON TUESDAY NORTHEAST OF I-94 FOR
THE CONVECTION DROPPING SOUTHEAST...WHICH COULD BE SEVERE AS WELL.
THE REST OF THE AREA LOOKS CAPPED. TALKING ABOUT THE CAPPING...925MB
TEMPS ARE PROGGED TO REACH ABOUT 28C ON I-94 TO 30C IN NORTHEAST
IOWA. THESE READINGS SHOULD YIELD HIGHS RANGING FROM THE LOW TO
UPPER 90S...WARMEST IN RIVER VALLEYS. THE EXCESSIVE HEAT WARNING MAY
NEED EXPANSION INTO SOME OF NORTHEAST IOWA AND FAR SOUTHWEST WI IF
TEMP/DEWPOINT TRENDS CONTINUE. ALL CONVECTION LOOKS LIKE IT WILL BE
SOUTHEAST OF THE AREA FOR TUESDAY NIGHT...THUS WENT DRY THEN.
DRY CONDITIONS ARE EXPECTED FOR WEDNESDAY AND WEDNESDAY NIGHT AS
HIGH PRESSURE BUILDS OVER WISCONSIN AND MICHIGAN IN THE WAKE OF
TUESDAYS LOW AND COLD FRONTAL PASSAGE. 925MB TEMPS OF 24-26C STILL
SUPPORTS HIGHS IN THE MID 80S TO LOW 90S...THOUGH. DEWPOINTS MAY
STILL BE UP IN THE LOW 70S OVER NORTHEAST IOWA...BUT HEAT INDICES
ARE MORE AROUND 95 VERSUS THE 100-105 AS OF LATE.
THURSDAY THROUGH SATURDAY FEATURE A GRADUAL WARM ADVECTION
PATTERN...WHICH MEANS A RETURN FOR SOME CHANCES OF SHOWERS AND
THUNDERSTORMS. HIGHEST CHANCES ARE FORECAST THURSDAY NIGHT OVER
WISCONSIN WHERE THERE APPEARS TO BE A JUXTAPOSITION OF RIGHT
ENTRANCE REGION FORCING...A POSSIBLE SHORTWAVE MOVING THROUGH...AND
THE LOW LEVEL MOISTURE TRANSPORT. SOME OF THESE CHANCES OF SHOWERS
AND THUNDERSTORMS MAY BE ABLE TO BE BETTER REFINED...IN TERMS OF
DRYING SOME OUT...OVER THE COMING DAYS AS MODELS SETTLE INTO THE
TIMING OF THE WARM ADVECTION. ONCE THE WARM AIR COMES IN...WE WILL
HAVE TO BE CONCERNED WITH HEAT ADVISORIES...AS EVEN THE NEW 26.00Z
ECMWF SHOWS 925MB TEMPS APPROACHING 30C OVER WESTERN PORTIONS OF THE
FORECAST AREA LATE FRIDAY.
SUNDAY AND THE REST OF LABOR DAY WEEKEND FORECAST IS NOW UP IN THE
AIR DUE TO THE NEW 26.00Z ECMWF. PREVIOUSLY AND IN AGREEMENT WITH
THE 26.00Z GFS IT APPEARED MUCH OF THE AREA WOULD BE IN THE WARM
SECTOR...WITH 925MB TEMPS OF 29-32C WHICH COULD ALLOW FOR HIGHS
AROUND 100. IF THE NEW ECMWF IS RIGHT...WE GET A MOSTLY DRY COLD
FRONTAL PASSAGE ON SUNDAY WITH HIGHS MORE IN THE MID TO UPPER 80S.
MONDAY ENDS UP MUCH MUCH COOLER WITH HIGHS MOSTLY IN THE 60S.
COMPARE THIS TO ITS PREVIOUS 4 RUNS SHOWING 94-98 AT LA CROSSE FOR
MONDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 640 AM CDT MON AUG 26 2013
EXPECT THE LOW LEVEL WIND SHEAR AT KLSE TO RAPIDLY DISSIPATE BY
26.14Z AS THE LOW LEVEL JET AND PRESSURE GRADIENT WEAKENS...AND
THE NOCTURNAL INVERSION DISSIPATES THROUGH DIURNAL MIXING.
FOR TODAY...EXPECT ONLY SCATTERED 15K FOOT CLOUDS. WINDS WILL GUST
FROM SOUTHWEST INTO THE 15 TO 25 KNOT RANGE.
AFTER 27.07Z...THERE IS CONCERN THAT LOW LEVEL WIND SHEAR WILL
DEVELOP AT KLSE AS THE WINDS DROP TO LESS THAN 10 KNOTS BELOW THE
NOCTURNAL INVERSION AND THE LOW LEVEL JET STRENGTHENS ALOFT. THE
GFS HAS THIS JET CLIMBING INTO THE 30 TO 35 KNOT RANGE. MEANWHILE
THE NAM/WRF HAS THIS JET STRENGTHENING INTO THE 40 TO 45 KNOT
RANGE. DUE TO THE UNCERTAINTY OF THE STRENGTH OF THIS JET...HELD
OFF MENTIONING IT.
&&
.CLIMATE...
ISSUED AT 346 PM CDT SUN AUG 25 2013
THE FOLLOWING ARE RECORD HIGHS FOR LA CROSSE AND ROCHESTER
THROUGH LABOR DAY WEEKEND...GIVEN THE HEAT FORECAST. FOR MORE
CLIMATE INFORMATION...SEE OUR WEBSITE AND THE TOP NEWS STORY ON
THE HEAT.
LA CROSSE ROCHESTER
--------- ---------
MON 8/26 96/1991 95/1955
TUE 8/27 95/1973 93/1984
WED 8/28 97/1955 96/1955
THU 8/29 95/1966 92/2012
FRI 8/30 97/2012 96/1941
SAT 8/31 95/1953 93/1960
SUN 9/1 98/1913 94/1937
MON 9/2 98/1937 94/1929
NORMAL HIGH TEMPERATURES THROUGH THIS PERIOD ARE 78-80 AT LA CROSSE
AND 76-78 AT ROCHESTER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR WIZ017-029-
034-042>044-053>055-061.
EXCESSIVE HEAT WARNING UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR
WIZ032-033-041.
MN...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR MNZ086-087-
094-095.
EXCESSIVE HEAT WARNING UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR
MNZ079-088-096.
IA...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR IAZ008>011-
018-019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...BOYNE
CLIMATE...WETENKAMP
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
339 AM CDT MON AUG 26 2013
.TODAY AND TONIGHT...FORECAST CONFIDENCE IS MEDIUM.
COLD POOL FINALLY STARTING TO TAKE CONVECTIVE COMPLEX ACROSS NRN
WI TO THE SOUTH SOUTHEAST. WILL HAVE TO SEE HOW IT SURVIVES AS IT
RUNS INTO 700MB THERMAL RIDGE OVER CENTRAL WI...THOUGH WEAK SHORT
WAVE MOVING ACROSS REGION HAS COOLED 700MB TEMPS TO BETWEEN 10C
AND 11C OVER E CENTRAL AND S CENTRAL WI. CURRENT TRACK WOULD BRING
COMPLEX INTO FAR NRN CWA AROUND 830 AM. HRRR AND HI-RES ARW MODELS
TAKE BULK OF COMPLEX TO THE EAST. WILL FOLLOW CURRENT CONSENSUS
THAT TAKES THIS MORE EASTERLY TRACK...BUT WILL MONITOR CLOSELY.
SOME SIGNAL IN MODEL QPF THAT RESIDUAL OUTFLOW BOUNDARY COULD BE
FOCUS FOR AFTERNOON/EVENING CONVECTION AS NEXT SHORT WAVE TOPS
RIDGE AND CROSSES NRN WI/UP OF MI TONIGHT. SPC STORM SCALE
ENSEMBLE OF OPPORTUNITY/SSEO SHOWS BETTER PROBABILITY FOR UPDRAFT
HELICITY EXCEEDING 25M2/S2..A GOOD INDICATOR FOR ROTATING/SEVERE
STORMS...AND REFLECTIVITIES GREATER THAN 40 DBZ REMAIN ACROSS NRN
WI THOUGH A 10 TO 20 PCT HELICITY PROB AND 50 TO 60 PCT
REFLECTIVITY PROB DO DIP INTO THE FAR NRN CWA AFTER 06Z IN LINE
WITH SOUTHERN EDGE OF CURRENT DAY ONE OUTLOOK. WITH CAP
STRENGTHENING FROM NORTH TO SOUTH THROUGH CWA WILL LIMIT MAINLY
SLIGHT CHANCE/CHANCE POPS TO THE NORTHEAST THIRD.
925MB TEMPERATURES SUPPORT HIGHS A FEW DEGREES WARMER THAN
YESTERDAY...WITH UPPER 80S IN THE FAR EAST AND LOW TO MID 90S IN
THE WEST. A FEW SPOTS IN THE FAR WEST WILL REACH HEAT INDEX VALUES
OF 100F...BUT AREAL EXTENT TOO SMALL TO ISSUE A HEADLINE. WILL
CONTINUE HIGHLIGHTING IN SPS/HWO/TOP NEWS FOR NOW. A WARM MUGGY
NIGHT TONIGHT WITH LOWS ONLY COOLING TO THE 70S.
.TUESDAY THROUGH WEDNESDAY NIGHT...FORECAST CONFIDENCE IS MEDIUM.
SHORT TERM MODELS SHOW THE 500MB HIGH REMAINING ACROSS SOUTHWEST
MISSOURI DURING THIS PERIOD...KEEPING NORTHWESTERLY FLOW AT THIS
LEVEL ACROSS THE WESTERN GREAT LAKES REGION. SHEARED VORTICITY
MAXIMA SHIFT THROUGH THE AREA TUESDAY AFTERNOON INTO WEDNESDAY.
A WEAK SURFACE LOW MOVING FROM CENTRAL MINNESOTA AT 12Z TUESDAY
SOUTHEAST INTO OR CLOSE TO SOUTHERN WISCONSIN BY 00Z WEDNESDAY. IT
THEN WASHES OUT TUESDAY NIGHT. QUASISTATIONARY FRONTAL BOUNDARY
EXTENDS EAST FROM THE WEAK LOW ACROSS CENTRAL WISCONSIN
TUESDAY...BEFORE SLIDING SOUTHWARD ACROSS THE AREA LATER TUESDAY
AND TUESDAY NIGHT AS A COLD FRONT.
LOW LEVEL JET NOSE/FOCUSED WARM AIR ADVECTION WILL SUPPORT AN MCS
SHIFTING EAST SOUTHEAST ACROSS NORTHERN AND CENTRAL WISCONSIN
TUESDAY MORNING...POSSIBLY CLIPPING THE NORTHERN AND NORTHEASTERN
PORTIONS OF THE FORECAST AREA. MEAN LAYER CAPES INCREASE DURING
THE MORNING ABOVE CAP...WITH ENOUGH DEEP LAYER SHEAR TO BRING AN
OUTSIDE CHANCE FOR A SEVERE STORM OR TWO. HIGH PRECIPITABLE WATER
VALUES TO AROUND 2 INCHES SUGGEST LOCALLY HEAVY RAINFALL WOULD
ALSO BE POSSIBLE WITH ANY CONVECTION. CONTINUED CHANCE POPS FOR
NOW IN THE NORTH AND NORTHEAST COUNTIES...GIVEN SOME UNCERTAINTY
WITH THE TRACK OF THE MCS.
NAM MORE AGGRESSIVE WITH LOW LEVEL FRONTOGENESIS RESPONSE WITH
FRONT SLIDING SOUTH THROUGH THE AREA LATER TUESDAY AND TUESDAY
NIGHT THAN THE GFS. STILL...ENOUGH UPWARD MOTION WITH FRONT TO
COMBINE WITH MEAN LAYER CAPE AND DEEP LAYER SHEAR TO BRING
POSSIBILITY OF MULTICELL STORMS WITH SEVERE POTENTIAL LATER
TUESDAY INTO TUESDAY EVENING. BEST SHOT IN THE NORTH AND EAST
WHERE SPC DAY 2 SLIGHT RISK IS LOCATED. LOCALLY HEAVY RAINFALL
REMAINS POSSIBLE WITH HIGH PRECIPITABLE WATER VALUES. BOTH NAM AND
GFS BRING SOME QPF THROUGH THE AREA...MAINLY IN THE EAST BY
EVENING. KEPT CHANCE POPS GOING DURING THE AFTERNOON...MAINLY IN
THE NORTH AND EAST.
MEAN LAYER CAPES FALL OFF QUICKLY DURING THE EVENING AS THE FRONT
PASSES THROUGH. CONTINUED CHANCE POPS IN THE EVENING...THEN DROP
OFF AFTER MIDNIGHT. MOISTURE LINGERING BEHIND THE FRONT WITH
COOLER AIR MOVING IN SHOULD GENERATE PATCHY FOG ACROSS THE AREA
LATER TUESDAY NIGHT.
SOUTHWEST WINDS WILL LINGER TUESDAY ACROSS THE AREA...AND SHOULD
COMBINE WITH 925MB TEMPERATURES IN THE UPPER 20S CELSIUS RANGE TO
BRING LOWER TO MID 90S TO MOST OF THE AREA...HIGHEST IN SOUTH
CENTRAL WISCONSIN.
BIG QUESTION IS IF CIRRUS FROM POSSIBLE CONVECTION TO THE NORTH
AND NORTHEAST MOVES OFF BY THE AFTERNOON. IF IT DOES...SHOULD SEE
THE LOWER TO MID 90S OCCUR. HEAT INDEX VALUES WILL BE IN THE 97 TO
102 RANGE IN MOST OF SOUTH CENTRAL AND SOUTHEAST WISCONSIN...SO A
HEAT ADVISORY FOR TUESDAY AFTERNOON AND EARLY EVENING WOULD BE
NECESSARY. IF THE CLOUDS HANG AROUND INTO THE AFTERNOON...THEY
WILL HOLD DOWN TEMPERATURES ENOUGH TO PREVENT HEAT INDEX VALUES
FROM REACHING 100 DEGREES. THUS...WILL HOLD OFF ON ANY HEAT
HEADLINES UNTIL BETTER HANDLE ON POSSIBLE CONVECTION AND CLOUDS
IS GAINED.
SLIGHTLY COOLER AIRMASS WORKS SOUTHWARD INTO THE AREA FOR
WEDNESDAY AND WEDNESDAY NIGHT...AS HIGH PRESSURE WORKS INTO THE
REGION. LOWER 80S NEAR THE LAKE WITH MID TO UPPER 80S INLAND ARE
EXPECTED WEDNESDAY. NAM HAS ODD LOOKING QPF IN THE AREA WEDNESDAY
WITH SOME LINGERING MEAN LAYER CAPE. THE GFS IS DRY AND SEEMS MORE
REASONABLE. THUS...QUIET WEATHER IS EXPECTED WEDNESDAY AND
WEDNESDAY NIGHT.
.THURSDAY THROUGH SUNDAY...FORECAST CONFIDENCE IS MEDIUM.
GFS AND ECMWF SHOWING SOMEWHAT SIMILAR TRENDS DURING THIS PERIOD.
THEY TAKE HIGH PRESSURE EAST OF THE AREA THURSDAY...WITH WEAK LOW
PRESSURE REMAINING IN EASTERN SOUTH DAKOTA THURSDAY NIGHT INTO
FRIDAY. BOTH MODELS SHOW QPF MOVING SOUTHEAST INTO THE AREA
THURSDAY NIGHT AND LINGERING INTO FRIDAY...RIDING THE
QUASISTATIONARY SURFACE BOUNDARY AND LOW LEVEL THERMAL RIDGE. THIS
BOUNDARY THEN REMAINS IN THE SAME AREA INTO SATURDAY
EVENING...WITH MORE QPF IN OR NEAR THE AREA.
WARM AIR ADVECTION PUSH SUNDAY PER GFS BRINGS HOT AND HUMID
CONDITIONS BACK TO THE AREA WITH SOUTHWEST WINDS. ECMWF BRINGS
COLD FRONT THROUGH THE AREA SUNDAY AND COOLS THINGS DOWN SOMEWHAT.
MOST IF NOT ALL OF THE QPF ASSOCIATED WITH WARM FRONT REMAINS
NORTH OF THE AREA SUNDAY PER GFS. FOR NOW...USED CONSENSUS POPS
AND TEMPERATURES FOR THE THURSDAY THROUGH SUNDAY PERIOD...WITH 90S
ACROSS MOST OF THE AREA BY SUNDAY.
&&
.AVIATION/12Z TAFS/...WILL CONTINUE VFR CONDITIONS AT THE TAF
SITES WITH AN EYE TOWARD NRN WI COMPLEX THAT IS FINALLY TAKING THE
EXPECTED TURN TO THE SOUTH SOUTHEAST. PUT IN A SLIGHT CHANCE FOR
THUNDERSTORMS ALONG AND NORTHEAST OF AN OXFORD TO MEQUON LINE THIS
AFTERNOON FOR POSSIBLE DEVELOPMENT ALONG OUTFLOW FROM THIS COMPLEX
THAT IS EXPECTED TO PASS TO THE EAST INTO LOWER MI.
WILL KEEP CLOSE WATCH FOR POTENTIAL OF STORMS TO REACH UES AND MKE
AROUND 16Z IF THE COMPLEX TAKES MORE OF A SOUTHERLY TRACK. ANOTHER
CHANCE AT THUNDERSTORMS TONIGHT INTO TUESDAY BUT AGAIN MAJORITY OF
MODEL GUIDANCE KEEPS CONVECTION NORTH OF TAF SITES...THOUGH UES
AND MKE WOULD AGAIN HAVE THE BETTER CHANCE TO SEE STORMS IF THEY
MAKE IT FARTHER SOUTH THAN EXPECTED.
&&
.MARINE...WIND GUSTS WILL APPROACH SMALL CRAFT ADVISORY LEVELS IN
NORTHERN ZONES TODAY...BUT NOT FREQUENT ENOUGH FOR A HEADLINE.
THUNDERSTORM CHANCES LOOK TO BE BETTER FROM MILWAUKEE NORTH...LATE
THIS MORNING INTO EARLY AFTERNOON...AND AGAIN LATE TONIGHT INTO
TUESDAY MORNING.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...REM
TUESDAY THROUGH SUNDAY...WOOD
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
326 AM CDT MON AUG 26 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 309 AM CDT MON AUG 26 2013
..CURRENTLY AS OF 08Z..
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED TROUGHING OVER
THE PACIFIC NORTHWEST AND EASTERN PACIFIC...AND STRONG SUBTROPICAL
RIDGING OVER KANSAS AND MISSOURI. MONSOONAL MOISTURE AND SHORTWAVES
CONTINUES TO STREAM OUT OF BAJA CALIFORNIA...UP THROUGH THE DAKOTAS
AND INTO THE NORTHERN GREAT LAKES AROUND THE SUBTROPICAL RIDGE. ONE
SUCH SHORTWAVE COMBINED WITH 700MB MOISTURE TRANSPORT SUPPORTING
CONVECTION TRACKING ACROSS FAR NORTHERN WI AND UPPER MICHIGAN.
REGARDING MOISTURE...GOES DERIVED PRECIPITABLE WATER IMAGERY SHOWED
VALUES OF 1.5-2 INCHES FROM EASTERN SOUTH DAKOTA INTO THE NORTHERN
GREAT LAKES. AIRMASS IS ALSO VERY WARM WITH 850MB TEMPS FROM 00Z
RAOBS OF 22-24C ACROSS THE FORECAST AREA AND 24-28C OVER THE
NORTHERN PLAINS. WITH THE FORECAST AREA IN THE WARM SECTOR...SOUTH
OF A WARM FRONT POSITIONED OVER FAR NORTHERN WI...A SOUTHERLY BREEZE
HAS ONLY ALLOWED TEMPS TO FALL INTO THE MID TO UPPER 70S. THIS SAME
SOUTHERLY BREEZE HAS ADVECTED IN SOME LOWER DEWPOINTS...WHICH HAVE
FALLEN INTO THE 60S...LOWEST IN THE SOUTHEAST HALF OF THE AREA. 00Z
DVN SOUNDING REALLY SHOWED THE DRIER AIR COMPARED TO MPX.
..MODEL VERIFICATION..
HAVE INCLUDED THIS SECTION AS IT HAS HIGH IMPORTANCE WITH THE
FORECAST OF HIGH TEMPERATURES AND CONVECTION. LOOKING AT 00Z RAOBS
FOR 925MB TEMPS AND COMPARING TO 25.00Z MODEL GUIDANCE...THE ECMWF
WAS THE BEST WITH ALMOST NO ERROR ACROSS THE NORTHERN PLAINS AND
UPPER MIDWEST. THE GFS WAS GENERALLY 1-2C TOO HIGH. LASTLY...THE
NAM/RAP WERE THE WORST...HAVING ERRORS ON THE ORDER OF 3-6C...
HIGHEST AT MSP. BECAUSE THE NAM/RAP WERE TOO HIGH...IT BROKE THE CAP
AND BROUGHT THE CONVECTION WAY TOO FAR SOUTH.
..HAZARDS..
1. HEAT. TEMPERATURES ARE LIKELY TO BE A FEW DEGREES HIGHER TODAY
AND WITH DEWPOINTS CLIMBING BACK INTO THE LOW 70S...HEAT INDICES
SHOULD TOP OUT IN THE 100-105 RANGE. THE HIGHEST HEAT INDICES LOOK
TO OCCUR FROM LAKE CITY DOWN TO LA CROSSE...AND HAVE UPGRADED THIS
AREA TO AN EXCESSIVE HEAT WARNING.
2. STORMS. SOME SEVERE POTENTIAL AFTER MIDNIGHT TONIGHT...MAINLY
ACROSS TAYLOR/CLARK COUNTIES. HAVE TO WATCH RAINFALL AMOUNTS TOO.
..SYNOPTIC OVERVIEW..
26.00Z MODEL GUIDANCE SUGGESTS THE SUBTROPICAL RIDGING RETROGRADES
JUST SLIGHTLY WESTWARD DURING THE NEXT 24 HOURS. THE MAIN FEATURE OF
FOCUS IS A STRETCHED OUT SHORTWAVE IN THE MONSOONAL FLOW...LOCATED
FROM EASTERN UTAH INTO SOUTH CENTRAL WYOMING. MODELS BRING THIS
SHORTWAVE INTO THE DAKOTAS BY 00Z AND PERHAPS AS FAR EAST AS WESTERN
UPPER MI BY 12Z. THIS SHORTWAVE HELPS TO LIFT A SURFACE LOW SITTING
NEAR THE BLACK HILLS OF SOUTH DAKOTA TO NEAR MINNEAPOLIS BY 12Z TUE.
..DETAILS..
FOCUS FOR POTENTIAL CONVECTION TODAY WILL LIE ON THE LOCATION OF THE
WARM FRONT IN NORTHERN WI. FIRST OFF...THE CURRENT CONVECTION
CROSSING FAR NORTHERN WI AND UPPER MI COULD DROP INTO TAYLOR AND
POSSIBLY CLARK COUNTY BEFORE WEAKENING THIS MORNING. THE OUTFLOW
FROM THE CONVECTION SHOULD HELP PUSH THE FRONT SOUTH TOWARDS I-94
THIS AFTERNOON. THEN...THE NEXT QUESTION IS IF THE AIRMASS IS
CAPPED...WHICH ENTIRELY DEPENDS ON HOW WARM WE GET. THERE SHOULD BE
PLENTY OF SUN TODAY ACROSS THE FORECAST AREA WITH MAYBE A FEW STRAY
CIRRUS CLOUDS. ECMWF 925MB TEMPS ARE PROGGED ABOUT 1-2C HIGHER
COMPARED TO YESTERDAY...THUS ANTICIPATING HIGHS TO BE ABOUT 1-3F
HIGHER... YIELDING READINGS MAINLY IN THE LOW TO MID 90S. A FEW
SPOTS LIKE LSE COULD EVEN HIT THE UPPER 90S. ECMWF ALSO DID VERY
WELL WITH THE DEWPOINTS YESTERDAY AND SUGGESTS THEY SHOULD CLIMB
INTO THE LOW 70S IN THE AFTERNOON...DUE TO EVAPOTRANSPORATION AND
THE HIGHER MOISTURE TO OUR NORTHWEST SLIDING SOUTH. THE FORECAST
HIGHS AND DEWPOINTS WOULD SEEM TO POINT TO POTENTIAL FOR THE CAP TO
BREAK...THUS HAVE INCLUDED 20-40 PERCENT CHANCES ON THE WARM FRONT
FOR THE AFTERNOON. SHOULD STORMS DEVELOP...0-6KM SHEAR IS ONLY 25 KT
AT BEST WITH 0-3KM NEAR 20KT. THIS MEANS THE STORMS WILL PROBABLY BE
UNORGANIZED AND MOST LIKELY JUST HEAVY RAIN MAKERS GIVEN HIGH CAPE
AND NEAR 2 INCH PRECIPITABLE WATERS.
TONIGHT IS A BIT MORE INTERESTING. A CONVECTIVE COMPLEX APPEARS
LIKELY TO DEVELOP IN THE GRAND FORKS AREA IN THE EVENING AHEAD OF
THE SHORTWAVE. THIS CONVECTION...AIDED ALSO BY 700MB MOISTURE
TRANSPORT LIKE THE CONVECTION GOING OVER UPPER MI...SHOULD TRACK
EAST-SOUTHEAST INTO NORTHERN WI. THIS MEANS TAYLOR/CLARK COULD BE
IMPACTED BY THE COMPLEX AFTER MIDNIGHT. ADDITIONAL CONVECTION COULD
FORM ON THE NOSE OF 850MB MOISTURE TRANSPORT NORTH OF I-94 THIS
EVENING AS WELL. CANNOT RULE OUT SOME SEVERE WEATHER...LIKELY IN THE
FORM OF DAMAGING WINDS AND LARGE HAIL...ESPECIALLY AFTER MIDNIGHT
WHEN 0-6 KM SHEAR VALUES APPROACH 30-40 KT. THE REST OF THE AREA
SHOULD STAY MAINLY DRY...CAPPED AND WARM WITH A SOUTHERLY BREEZE
PERSISTING. LOW TEMPERATURES ARE LIKELY TO BE SIMILAR TO NOW GIVEN
SIMILAR CONDITIONS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 309 AM CDT MON AUG 26 2013
..HAZARDS..
1. HEAT...WHICH WILL PERSIST INTO TUESDAY. COLD FRONT COMES THROUGH
TUESDAY NIGHT WHICH SHOULD HELP ADVECT BOTH SOMEWHAT COOLER AND MORE
IMPORTANTLY DRIER AIR INTO THE AREA FOR WEDNESDAY. HEAT LOOKS TO
RETURN DURING LABOR DAY WEEKEND.
2. STORMS. THOSE ON TUESDAY COULD POSE A SEVERE AND HEAVY RAIN
THREAT NORTH OF I-94.
..SYNOPTIC OVERVIEW..
26.00Z MODEL GUIDANCE CONTINUES TO SUGGEST THAT THE SUBTROPICAL HIGH
WILL RETROGRADE WESTWARD THROUGH THE WEEK...ENDING UP IN COLORADO ON
FRIDAY. THIS RETROGRESSION IS IN RESPONSE TO A SERIES OF SHORTWAVE
TROUGHS DROPPING INTO THE MID-ATLANTIC REGION ON THE EAST SIDE OF
THE RIDGE. AS WE HEAD INTO THE WEEKEND...THE SUBTROPICAL RIDGE WILL
SHIFT EAST IN RESPONSE TO WHAT LOOKS TO BE A VERY DEEP TROUGH FOR
THIS TIME OF YEAR COMING INTO THE PACIFIC NORTHWEST. IT SHOULD BE
NOTED THAT THE 26.00Z ECMWF THROWS A MAJOR CURVE BALL TO THE WEEKEND
PLAN...DEVIATING GREATLY FROM ITS PREVIOUS RUN IN SHOWING A TROUGH
DIGGING INTO THE WESTERN GREAT LAKES LATE SUNDAY. THE REASON IS
RELATED TO THIS TROUGH BEING STRONGER AND TRACKING FARTHER SOUTH
COMING OUT OF SOUTHWEST CANADA ON FRIDAY...COMPARED TO ITS PREVIOUS
RUN...THE 26.00Z GFS AND CANADIAN. NOT READY TO FULLY BUY INTO THE
26.00Z ECMWF QUITE YET BEFORE SEEING THE ECMWF ENSEMBLES AND ITS
NEXT RUN.
..DETAILS..
THE SURFACE OVER CENTRAL MN AT 12Z TUESDAY WILL GRADUALLY DROP
SOUTHEAST THROUGH TUESDAY AND TUESDAY NIGHT...IN RESPONSE TO THE
SHORTWAVE AND CONVECTION OVER NORTHERN WI/UPPER MI DROPPING
SOUTHEAST. HAVE KEPT SOME CHANCES ON TUESDAY NORTHEAST OF I-94 FOR
THE CONVECTION DROPPING SOUTHEAST...WHICH COULD BE SEVERE AS WELL.
THE REST OF THE AREA LOOKS CAPPED. TALKING ABOUT THE CAPPING...925MB
TEMPS ARE PROGGED TO REACH ABOUT 28C ON I-94 TO 30C IN NORTHEAST
IOWA. THESE READINGS SHOULD YIELD HIGHS RANGING FROM THE LOW TO
UPPER 90S...WARMEST IN RIVER VALLEYS. THE EXCESSIVE HEAT WARNING MAY
NEED EXPANSION INTO SOME OF NORTHEAST IOWA AND FAR SOUTHWEST WI IF
TEMP/DEWPOINT TRENDS CONTINUE. ALL CONVECTION LOOKS LIKE IT WILL BE
SOUTHEAST OF THE AREA FOR TUESDAY NIGHT...THUS WENT DRY THEN.
DRY CONDITIONS ARE EXPECTED FOR WEDNESDAY AND WEDNESDAY NIGHT AS
HIGH PRESSURE BUILDS OVER WISCONSIN AND MICHIGAN IN THE WAKE OF
TUESDAYS LOW AND COLD FRONTAL PASSAGE. 925MB TEMPS OF 24-26C STILL
SUPPORTS HIGHS IN THE MID 80S TO LOW 90S...THOUGH. DEWPOINTS MAY
STILL BE UP IN THE LOW 70S OVER NORTHEAST IOWA...BUT HEAT INDICES
ARE MORE AROUND 95 VERSUS THE 100-105 AS OF LATE.
THURSDAY THROUGH SATURDAY FEATURE A GRADUAL WARM ADVECTION
PATTERN...WHICH MEANS A RETURN FOR SOME CHANCES OF SHOWERS AND
THUNDERSTORMS. HIGHEST CHANCES ARE FORECAST THURSDAY NIGHT OVER
WISCONSIN WHERE THERE APPEARS TO BE A JUXTAPOSITION OF RIGHT
ENTRANCE REGION FORCING...A POSSIBLE SHORTWAVE MOVING THROUGH...AND
THE LOW LEVEL MOISTURE TRANSPORT. SOME OF THESE CHANCES OF SHOWERS
AND THUNDERSTORMS MAY BE ABLE TO BE BETTER REFINED...IN TERMS OF
DRYING SOME OUT...OVER THE COMING DAYS AS MODELS SETTLE INTO THE
TIMING OF THE WARM ADVECTION. ONCE THE WARM AIR COMES IN...WE WILL
HAVE TO BE CONCERNED WITH HEAT ADVISORIES...AS EVEN THE NEW 26.00Z
ECMWF SHOWS 925MB TEMPS APPROACHING 30C OVER WESTERN PORTIONS OF THE
FORECAST AREA LATE FRIDAY.
SUNDAY AND THE REST OF LABOR DAY WEEKEND FORECAST IS NOW UP IN THE
AIR DUE TO THE NEW 26.00Z ECMWF. PREVIOUSLY AND IN AGREEMENT WITH
THE 26.00Z GFS IT APPEARED MUCH OF THE AREA WOULD BE IN THE WARM
SECTOR...WITH 925MB TEMPS OF 29-32C WHICH COULD ALLOW FOR HIGHS
AROUND 100. IF THE NEW ECMWF IS RIGHT...WE GET A MOSTLY DRY COLD
FRONTAL PASSAGE ON SUNDAY WITH HIGHS MORE IN THE MID TO UPPER 80S.
MONDAY ENDS UP MUCH MUCH COOLER WITH HIGHS MOSTLY IN THE 60S.
COMPARE THIS TO ITS PREVIOUS 4 RUNS SHOWING 94-98 AT LA CROSSE FOR
MONDAY.
&&
.AVIATION...EARLY THIS MORNING
ISSUED AT 326 AM CDT MON AUG 26 2013
THE VALLEY HAS DECOUPLED IN THE MISSISSIPPI RIVER VALLEY EARLY THIS
MORNING. THIS HAS ALLOWED THE WINDS TO FALL BELOW 10 KNOTS.
MEANWHILE ON NOCTURNAL LOW LEVEL JET AND THE TIGHT PRESSURE GRADIENT
OVER THE AREA. RAP SOUNDINGS SUGGEST THE WINDS AT 1300 FEET JUST
ABOVE THE NOCTURNAL INVERSION ARE BLOWING OUT OF THE SOUTHWEST AT 40
TO 45 KNOTS. AS A RESULT...HAVE UPDATED THE KLSE TAF TO ADD LOW
LEVEL WIND SHEAR. THE WIND SHEAR WILL DISSIPATE QUICKLY AROUND
26.14Z IN RESPONSE TO WEAKENING PRESSURE GRADIENT AND LOW LEVEL
JET...AND DIURNAL MIXING BREAKING DOWN THE INVERSION.
&&
.CLIMATE...
ISSUED AT 346 PM CDT SUN AUG 25 2013
THE FOLLOWING ARE RECORD HIGHS FOR LA CROSSE AND ROCHESTER
THROUGH LABOR DAY WEEKEND...GIVEN THE HEAT FORECAST. FOR MORE
CLIMATE INFORMATION...SEE OUR WEBSITE AND THE TOP NEWS STORY ON
THE HEAT.
LA CROSSE ROCHESTER
--------- ---------
MON 8/26 96/1991 95/1955
TUE 8/27 95/1973 93/1984
WED 8/28 97/1955 96/1955
THU 8/29 95/1966 92/2012
FRI 8/30 97/2012 96/1941
SAT 8/31 95/1953 93/1960
SUN 9/1 98/1913 94/1937
MON 9/2 98/1937 94/1929
NORMAL HIGH TEMPERATURES THROUGH THIS PERIOD ARE 78-80 AT LA CROSSE
AND 76-78 AT ROCHESTER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR WIZ017-029-
034-042>044-053>055-061.
EXCESSIVE HEAT WARNING UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR
WIZ032-033-041.
MN...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR MNZ086-087-
094-095.
EXCESSIVE HEAT WARNING UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR
MNZ079-088-096.
IA...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR IAZ008>011-
018-019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...RIECK
CLIMATE...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
309 AM CDT MON AUG 26 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 309 AM CDT MON AUG 26 2013
..CURRENTLY AS OF 08Z..
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED TROUGHING OVER
THE PACIFIC NORTHWEST AND EASTERN PACIFIC...AND STRONG SUBTROPICAL
RIDGING OVER KANSAS AND MISSOURI. MONSOONAL MOISTURE AND SHORTWAVES
CONTINUES TO STREAM OUT OF BAJA CALIFORNIA...UP THROUGH THE DAKOTAS
AND INTO THE NORTHERN GREAT LAKES AROUND THE SUBTROPICAL RIDGE. ONE
SUCH SHORTWAVE COMBINED WITH 700MB MOISTURE TRANSPORT SUPPORTING
CONVECTION TRACKING ACROSS FAR NORTHERN WI AND UPPER MICHIGAN.
REGARDING MOISTURE...GOES DERIVED PRECIPITABLE WATER IMAGERY SHOWED
VALUES OF 1.5-2 INCHES FROM EASTERN SOUTH DAKOTA INTO THE NORTHERN
GREAT LAKES. AIRMASS IS ALSO VERY WARM WITH 850MB TEMPS FROM 00Z
RAOBS OF 22-24C ACROSS THE FORECAST AREA AND 24-28C OVER THE
NORTHERN PLAINS. WITH THE FORECAST AREA IN THE WARM SECTOR...SOUTH
OF A WARM FRONT POSITIONED OVER FAR NORTHERN WI...A SOUTHERLY BREEZE
HAS ONLY ALLOWED TEMPS TO FALL INTO THE MID TO UPPER 70S. THIS SAME
SOUTHERLY BREEZE HAS ADVECTED IN SOME LOWER DEWPOINTS...WHICH HAVE
FALLEN INTO THE 60S...LOWEST IN THE SOUTHEAST HALF OF THE AREA. 00Z
DVN SOUNDING REALLY SHOWED THE DRIER AIR COMPARED TO MPX.
..MODEL VERIFICATION..
HAVE INCLUDED THIS SECTION AS IT HAS HIGH IMPORTANCE WITH THE
FORECAST OF HIGH TEMPERATURES AND CONVECTION. LOOKING AT 00Z RAOBS
FOR 925MB TEMPS AND COMPARING TO 25.00Z MODEL GUIDANCE...THE ECMWF
WAS THE BEST WITH ALMOST NO ERROR ACROSS THE NORTHERN PLAINS AND
UPPER MIDWEST. THE GFS WAS GENERALLY 1-2C TOO HIGH. LASTLY...THE
NAM/RAP WERE THE WORST...HAVING ERRORS ON THE ORDER OF 3-6C...
HIGHEST AT MSP. BECAUSE THE NAM/RAP WERE TOO HIGH...IT BROKE THE CAP
AND BROUGHT THE CONVECTION WAY TOO FAR SOUTH.
..HAZARDS..
1. HEAT. TEMPERATURES ARE LIKELY TO BE A FEW DEGREES HIGHER TODAY
AND WITH DEWPOINTS CLIMBING BACK INTO THE LOW 70S...HEAT INDICES
SHOULD TOP OUT IN THE 100-105 RANGE. THE HIGHEST HEAT INDICES LOOK
TO OCCUR FROM LAKE CITY DOWN TO LA CROSSE...AND HAVE UPGRADED THIS
AREA TO AN EXCESSIVE HEAT WARNING.
2. STORMS. SOME SEVERE POTENTIAL AFTER MIDNIGHT TONIGHT...MAINLY
ACROSS TAYLOR/CLARK COUNTIES. HAVE TO WATCH RAINFALL AMOUNTS TOO.
..SYNOPTIC OVERVIEW..
26.00Z MODEL GUIDANCE SUGGESTS THE SUBTROPICAL RIDGING RETROGRADES
JUST SLIGHTLY WESTWARD DURING THE NEXT 24 HOURS. THE MAIN FEATURE OF
FOCUS IS A STRETCHED OUT SHORTWAVE IN THE MONSOONAL FLOW...LOCATED
FROM EASTERN UTAH INTO SOUTH CENTRAL WYOMING. MODELS BRING THIS
SHORTWAVE INTO THE DAKOTAS BY 00Z AND PERHAPS AS FAR EAST AS WESTERN
UPPER MI BY 12Z. THIS SHORTWAVE HELPS TO LIFT A SURFACE LOW SITTING
NEAR THE BLACK HILLS OF SOUTH DAKOTA TO NEAR MINNEAPOLIS BY 12Z TUE.
..DETAILS..
FOCUS FOR POTENTIAL CONVECTION TODAY WILL LIE ON THE LOCATION OF THE
WARM FRONT IN NORTHERN WI. FIRST OFF...THE CURRENT CONVECTION
CROSSING FAR NORTHERN WI AND UPPER MI COULD DROP INTO TAYLOR AND
POSSIBLY CLARK COUNTY BEFORE WEAKENING THIS MORNING. THE OUTFLOW
FROM THE CONVECTION SHOULD HELP PUSH THE FRONT SOUTH TOWARDS I-94
THIS AFTERNOON. THEN...THE NEXT QUESTION IS IF THE AIRMASS IS
CAPPED...WHICH ENTIRELY DEPENDS ON HOW WARM WE GET. THERE SHOULD BE
PLENTY OF SUN TODAY ACROSS THE FORECAST AREA WITH MAYBE A FEW STRAY
CIRRUS CLOUDS. ECMWF 925MB TEMPS ARE PROGGED ABOUT 1-2C HIGHER
COMPARED TO YESTERDAY...THUS ANTICIPATING HIGHS TO BE ABOUT 1-3F
HIGHER... YIELDING READINGS MAINLY IN THE LOW TO MID 90S. A FEW
SPOTS LIKE LSE COULD EVEN HIT THE UPPER 90S. ECMWF ALSO DID VERY
WELL WITH THE DEWPOINTS YESTERDAY AND SUGGESTS THEY SHOULD CLIMB
INTO THE LOW 70S IN THE AFTERNOON...DUE TO EVAPOTRANSPORATION AND
THE HIGHER MOISTURE TO OUR NORTHWEST SLIDING SOUTH. THE FORECAST
HIGHS AND DEWPOINTS WOULD SEEM TO POINT TO POTENTIAL FOR THE CAP TO
BREAK...THUS HAVE INCLUDED 20-40 PERCENT CHANCES ON THE WARM FRONT
FOR THE AFTERNOON. SHOULD STORMS DEVELOP...0-6KM SHEAR IS ONLY 25 KT
AT BEST WITH 0-3KM NEAR 20KT. THIS MEANS THE STORMS WILL PROBABLY BE
UNORGANIZED AND MOST LIKELY JUST HEAVY RAIN MAKERS GIVEN HIGH CAPE
AND NEAR 2 INCH PRECIPITABLE WATERS.
TONIGHT IS A BIT MORE INTERESTING. A CONVECTIVE COMPLEX APPEARS
LIKELY TO DEVELOP IN THE GRAND FORKS AREA IN THE EVENING AHEAD OF
THE SHORTWAVE. THIS CONVECTION...AIDED ALSO BY 700MB MOISTURE
TRANSPORT LIKE THE CONVECTION GOING OVER UPPER MI...SHOULD TRACK
EAST-SOUTHEAST INTO NORTHERN WI. THIS MEANS TAYLOR/CLARK COULD BE
IMPACTED BY THE COMPLEX AFTER MIDNIGHT. ADDITIONAL CONVECTION COULD
FORM ON THE NOSE OF 850MB MOISTURE TRANSPORT NORTH OF I-94 THIS
EVENING AS WELL. CANNOT RULE OUT SOME SEVERE WEATHER...LIKELY IN THE
FORM OF DAMAGING WINDS AND LARGE HAIL...ESPECIALLY AFTER MIDNIGHT
WHEN 0-6 KM SHEAR VALUES APPROACH 30-40 KT. THE REST OF THE AREA
SHOULD STAY MAINLY DRY...CAPPED AND WARM WITH A SOUTHERLY BREEZE
PERSISTING. LOW TEMPERATURES ARE LIKELY TO BE SIMILAR TO NOW GIVEN
SIMILAR CONDITIONS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 309 AM CDT MON AUG 26 2013
..HAZARDS..
1. HEAT...WHICH WILL PERSIST INTO TUESDAY. COLD FRONT COMES THROUGH
TUESDAY NIGHT WHICH SHOULD HELP ADVECT BOTH SOMEWHAT COOLER AND MORE
IMPORTANTLY DRIER AIR INTO THE AREA FOR WEDNESDAY. HEAT LOOKS TO
RETURN DURING LABOR DAY WEEKEND.
2. STORMS. THOSE ON TUESDAY COULD POSE A SEVERE AND HEAVY RAIN
THREAT NORTH OF I-94.
..SYNOPTIC OVERVIEW..
26.00Z MODEL GUIDANCE CONTINUES TO SUGGEST THAT THE SUBTROPICAL HIGH
WILL RETROGRADE WESTWARD THROUGH THE WEEK...ENDING UP IN COLORADO ON
FRIDAY. THIS RETROGRESSION IS IN RESPONSE TO A SERIES OF SHORTWAVE
TROUGHS DROPPING INTO THE MID-ATLANTIC REGION ON THE EAST SIDE OF
THE RIDGE. AS WE HEAD INTO THE WEEKEND...THE SUBTROPICAL RIDGE WILL
SHIFT EAST IN RESPONSE TO WHAT LOOKS TO BE A VERY DEEP TROUGH FOR
THIS TIME OF YEAR COMING INTO THE PACIFIC NORTHWEST. IT SHOULD BE
NOTED THAT THE 26.00Z ECMWF THROWS A MAJOR CURVE BALL TO THE WEEKEND
PLAN...DEVIATING GREATLY FROM ITS PREVIOUS RUN IN SHOWING A TROUGH
DIGGING INTO THE WESTERN GREAT LAKES LATE SUNDAY. THE REASON IS
RELATED TO THIS TROUGH BEING STRONGER AND TRACKING FARTHER SOUTH
COMING OUT OF SOUTHWEST CANADA ON FRIDAY...COMPARED TO ITS PREVIOUS
RUN...THE 26.00Z GFS AND CANADIAN. NOT READY TO FULLY BUY INTO THE
26.00Z ECMWF QUITE YET BEFORE SEEING THE ECMWF ENSEMBLES AND ITS
NEXT RUN.
..DETAILS..
THE SURFACE OVER CENTRAL MN AT 12Z TUESDAY WILL GRADUALLY DROP
SOUTHEAST THROUGH TUESDAY AND TUESDAY NIGHT...IN RESPONSE TO THE
SHORTWAVE AND CONVECTION OVER NORTHERN WI/UPPER MI DROPPING
SOUTHEAST. HAVE KEPT SOME CHANCES ON TUESDAY NORTHEAST OF I-94 FOR
THE CONVECTION DROPPING SOUTHEAST...WHICH COULD BE SEVERE AS WELL.
THE REST OF THE AREA LOOKS CAPPED. TALKING ABOUT THE CAPPING...925MB
TEMPS ARE PROGGED TO REACH ABOUT 28C ON I-94 TO 30C IN NORTHEAST
IOWA. THESE READINGS SHOULD YIELD HIGHS RANGING FROM THE LOW TO
UPPER 90S...WARMEST IN RIVER VALLEYS. THE EXCESSIVE HEAT WARNING MAY
NEED EXPANSION INTO SOME OF NORTHEAST IOWA AND FAR SOUTHWEST WI IF
TEMP/DEWPOINT TRENDS CONTINUE. ALL CONVECTION LOOKS LIKE IT WILL BE
SOUTHEAST OF THE AREA FOR TUESDAY NIGHT...THUS WENT DRY THEN.
DRY CONDITIONS ARE EXPECTED FOR WEDNESDAY AND WEDNESDAY NIGHT AS
HIGH PRESSURE BUILDS OVER WISCONSIN AND MICHIGAN IN THE WAKE OF
TUESDAYS LOW AND COLD FRONTAL PASSAGE. 925MB TEMPS OF 24-26C STILL
SUPPORTS HIGHS IN THE MID 80S TO LOW 90S...THOUGH. DEWPOINTS MAY
STILL BE UP IN THE LOW 70S OVER NORTHEAST IOWA...BUT HEAT INDICES
ARE MORE AROUND 95 VERSUS THE 100-105 AS OF LATE.
THURSDAY THROUGH SATURDAY FEATURE A GRADUAL WARM ADVECTION
PATTERN...WHICH MEANS A RETURN FOR SOME CHANCES OF SHOWERS AND
THUNDERSTORMS. HIGHEST CHANCES ARE FORECAST THURSDAY NIGHT OVER
WISCONSIN WHERE THERE APPEARS TO BE A JUXTAPOSITION OF RIGHT
ENTRANCE REGION FORCING...A POSSIBLE SHORTWAVE MOVING THROUGH...AND
THE LOW LEVEL MOISTURE TRANSPORT. SOME OF THESE CHANCES OF SHOWERS
AND THUNDERSTORMS MAY BE ABLE TO BE BETTER REFINED...IN TERMS OF
DRYING SOME OUT...OVER THE COMING DAYS AS MODELS SETTLE INTO THE
TIMING OF THE WARM ADVECTION. ONCE THE WARM AIR COMES IN...WE WILL
HAVE TO BE CONCERNED WITH HEAT ADVISORIES...AS EVEN THE NEW 26.00Z
ECMWF SHOWS 925MB TEMPS APPROACHING 30C OVER WESTERN PORTIONS OF THE
FORECAST AREA LATE FRIDAY.
SUNDAY AND THE REST OF LABOR DAY WEEKEND FORECAST IS NOW UP IN THE
AIR DUE TO THE NEW 26.00Z ECMWF. PREVIOUSLY AND IN AGREEMENT WITH
THE 26.00Z GFS IT APPEARED MUCH OF THE AREA WOULD BE IN THE WARM
SECTOR...WITH 925MB TEMPS OF 29-32C WHICH COULD ALLOW FOR HIGHS
AROUND 100. IF THE NEW ECMWF IS RIGHT...WE GET A MOSTLY DRY COLD
FRONTAL PASSAGE ON SUNDAY WITH HIGHS MORE IN THE MID TO UPPER 80S.
MONDAY ENDS UP MUCH MUCH COOLER WITH HIGHS MOSTLY IN THE 60S.
COMPARE THIS TO ITS PREVIOUS 4 RUNS SHOWING 94-98 AT LA CROSSE FOR
MONDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY EVENING)
ISSUED AT 1100 PM CDT SUN AUG 25 2013
SHRA/TS HAVE DEVELOPED ALONG A SFC BOUNDARY AS THE LOW LEVEL
MOISTURE TRANSPORT/JET HAVE INCREASED INTO IT. LATEST HRRR SHOWING A
CHANGE OF HEART WILL HOW FAR SOUTH THIS PCPN WILL PROGRESS...KEEPING
IT MOSTLY OVER NORTHERN/NORTHEAST WI THROUGH THE OVERNIGHT HOURS.
00Z NAM12 AND LATEST RAP13 ALSO FAVORING THIS NOW. 00Z MPX SOUNDING
LIKELY SHOWS THE REASON WHY...AS THE LOW LEVEL CAPPING INVERSION
REMAINED IN PLACE. HOW FAR SOUTH THE SHRA/TS WOULD MAKE IT WAS
ALREADY IN QUESTION...AND CONFIDENCE IS HIGHER THAT THEY WON/T MAKE
IT TO THE TAF SITES NOW.
THE SFC FRONT SHOULD NUDGE BACK NORTH ON MONDAY...AND WILL SERVE AS
A FOCUS FOR MORE SHRA/TS MONDAY AFTERNOON-NIGHT. HERE AGAIN...THERE
COULD BE A THREAT FOR PCPN AT THE TAF SITES...DEPENDING ON WHERE THE
BOUNDARY LAYS UP AND THE TRACK OF AN UPPER LEVEL DISTURBANCE. TRENDS
FAVOR KEEPING THE SHRA/TS TO THE NORTH FOR NOW.
&&
.CLIMATE...
ISSUED AT 346 PM CDT SUN AUG 25 2013
THE FOLLOWING ARE RECORD HIGHS FOR LA CROSSE AND ROCHESTER
THROUGH LABOR DAY WEEKEND...GIVEN THE HEAT FORECAST. FOR MORE
CLIMATE INFORMATION...SEE OUR WEBSITE AND THE TOP NEWS STORY ON
THE HEAT.
LA CROSSE ROCHESTER
--------- ---------
MON 8/26 96/1991 95/1955
TUE 8/27 95/1973 93/1984
WED 8/28 97/1955 96/1955
THU 8/29 95/1966 92/2012
FRI 8/30 97/2012 96/1941
SAT 8/31 95/1953 93/1960
SUN 9/1 98/1913 94/1937
MON 9/2 98/1937 94/1929
NORMAL HIGH TEMPERATURES THROUGH THIS PERIOD ARE 78-80 AT LA CROSSE
AND 76-78 AT ROCHESTER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR WIZ017-029-
034-042>044-053>055-061.
EXCESSIVE HEAT WARNING UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR
WIZ032-033-041.
MN...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR MNZ086-087-
094-095.
EXCESSIVE HEAT WARNING UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR
MNZ079-088-096.
IA...HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR IAZ008>011-
018-019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...RIECK
CLIMATE...WETENKAMP
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
321 PM MDT MON AUG 26 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 315 PM MDT MON AUG 26 2013
CURRENT KCYS RADAR LOOP SHOWS SHOWERS AND TSTORMS JUST STARTING TO
DEVELOP ALONG THE FRONT RANGE FOOTHILLS AND THE SOUTHERN LARAMIE
RANGE THIS AFTERNOON. BELIEVE MOST OF THE ACTIVITY WILL REMAIN
ALONG I80 AND NEAR THE COLORADO BORDER TODAY ACROSS SOUTHEAST
WYOMING. FURTHER TO THE EAST ACROSS WESTERN NEBRASKA...THE
THERMAL RIDGE AXIS CONTINUES TO REMAIN OVER THE AREA RESULTING IN
HOT TEMPERATURES IN THE MID TO UPPER 90S. DRY AIR ALOFT AND
MIDLEVEL SUBSIDENCE WILL LIMIT MOST CONVECTION POTENTIAL THROUGH
THE EVENING...ALTHOUGH A FEW ISOLATED TSTORMS MAY DEVELOP ALONG
THE CHEYENNE RIDGE TOWARDS KIMBALL AND SIDNEY. THE TSTORMS WILL
QUICKLY DIMINISH IN INTENSITY AFTER SUNSET THIS EVENING.
SUBTROPICAL MOISTURE PLUME WILL SHIFT A BIT FURTHER NORTH AND WEST
FOR TUESDAY...SO KEPT SCATTERED POP (25 TO 50 PERCENT) ALONG AND
WEST OF THE LARAMIE RANGE. ISOLATED TSTORMS ARE POSSIBLE FOR THE
HIGH PLAINS OF SOUTHEAST WYOMING...BUT THINK THE COVERAGE WILL BE
SPARSE AS SOME DRIER AIR ALOFT MOVES INTO SOUTHEAST WYOMING.
ANOTHER HOT DAY IS EXPECTED FOR WESTERN NEBRASKA AS HIGHS CLIMB
INTO THE UPPER 90S.
FOR WEDNESDAY...THE RIDGE AXIS EXTENDING NORTHEASTWARD FROM THE
MAIN UPPER LEVEL HIGH WILL PUSH ACROSS THE AREA. ALTHOUGH THE GFS
IS MORE AGGRESSIVE WITH DEVELOPING AFTERNOON TSTORMS NEAR THE WEST
OF THE LARAMIE...BELIEVE THE DRY AIR AND SUBSIDENCE ALOFT WILL
GREATLY REDUCE COVERAGE OF THESE TSTORMS. KEPT POP BETWEEN 15 TO
25 PERCENT FOR THE LOWER ELEVATIONS AND UP TO 40 PERCENT FOR THE
MOUNTAINS. HOT TEMPERATURES WILL CONTINUE AND SPREAD WESTWARD INTO
SOUTHEAST WYOMING ON WEDNESDAY WITH HIGHS IN THE LOW TO MID 90S
POSSIBLE EAST OF A LINE FROM CHEYENNE TO DOUGLAS...WITH
TEMPERATURES NEAR 100 ACROSS THE LOWER ELEVATIONS OF WESTERN
NEBRASKA.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 330 PM MDT MON AUG 26 2013
BROKEN RECORD CONTINUES WITH AFTERNOON SHOWERS AND THUNDERSTORMS.
REALLY SOMETHING WRONG WITH THE LATEST ECMWF RUN AS IT IS SHOWING
COPIOUS AMOUNTS OF QPF THROUGH THE EXTENDED. HAVE DISCOUNTED ITS
SOLUTION FOR THE EXTENDED.
FOR THURSDAY...LOOKS PRETTY HOT WITH 700MB TEMPERATURES OF +16 TO
+18C. LOOKING AT MID TO UPPER 90S IN THE PANHANDLE AND MID 80S OUT
WEST. WINDS FAIRLY LIGHT...700MB WINDS UNDER 10KTS.
EVEN WARMER TEMPERATURES EXPECTED FRIDAY AS 700MB TEMPERATURES
CLIMB TO +18C ACROSS THE CWFA. COULD SEE HIGHS NEAR 100 OUT IN THE
PANHANDLE WITH 90S COMMON IN SOUTHEAST WYOMING. WENT SLIGHTLY OVER
THE BCALLBLEND GUIDANCE FOR TEMPERATURES...ESPECIALLY OUT IN THE
PANHANDLE. ITS OUTPUT JUST LOOKS WAY TOO LOW.
FOR THE WEEKEND...WE HAVE A WAVE MOVING UP NORTH FROM
TEXAS...WHICH IS MOST LIKELY SUBTROPICAL IN NATURE...THAT MAKES IT
INTO NORTHEASTERN COLORADO. COULD SEE A MORE WIDESPREAD RAIN
SHOWER EVENT AS THIS OCCURS. GIVEN THE PROBLEMS WITH THE ECMWF
THOUGH...STILL WENT UNDER GUIDANCE ON POPS...AND THEREFORE THE
EXTENDED PROCEDURE OUTPUT. WILL ADJUST AS THE EVENT DRAWS CLOSER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY MORNING)
ISSUED AT 1059 AM MDT MON AUG 26 2013
DO BELIEVE THUNDERSTORM CHANCES WILL BE MAINLY CONFINED TO THE
SOUTHERN LARAMIE RANGE AS WELL AS THE KLAR AND KCYS AERODROMES
THIS AFTERNOON. LATEST HRRR COMPOSITE REFLECTIVITY FORECAST
SHOWING THIS AREA THE PRIME AREA TODAY. SO...WENT AHEAD AND ADDED
TEMPO THUNDERSTORMS IN THE KLAR AND KCYS TAFS. VFR OTHERWISE WITH
CONVECTION ENDING SHORTLY AFTER 00Z.
&&
.FIRE WEATHER...
ISSUED AT 210 PM MDT MON AUG 26 2013
NO FIRE WEATHER CONCERNS THROUGH THE WEEK WITH DAYTIME HUMIDITIES
REMAINING ABOVE 20 PERCENT...AND GENERALLY BETWEEN 20 TO 35
PERCENT ACROSS THE WHOLE FORECAST AREA...WITH GREAT OVERNIGHT
RECOVERIES. NOT MUCH OF A PATTERN CHANGE ANTICIPATED OVER THE NEXT
7 DAYS AS A STUBBORN UPPER LEVEL HIGH WILL REMAIN NEARLY
STATIONARY BETWEEN THE CENTRAL ROCKIES AND CENTRAL GREAT PLAINS.
VERY WARM TEMPERATURES ARE EXPECTED TO CONTINUE THROUGH THE WEEK
AND EVEN INTO NEXT WEEKEND. DUE TO THE LOCATION OF THE UPPER LEVEL
HIGH THE JET STREAM WILL REMAIN WELL TO THE NORTH...SO LIGHT WINDS
WILL PREVAIL ACROSS THE AREA.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...TJT
LONG TERM...CLAYCOMB
AVIATION...CLAYCOMB
FIRE WEATHER...TJT
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1103 AM MDT MON AUG 26 2013
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 500 AM MDT MON AUG 26 2013
WATER VAPOR IMAGERY SHOWS THE STRONG UPPER RIDGE OVER THE CENTRAL
CONUS...WITH MOIST SUBTROPICAL FLOW MOVING UP FROM THE SOUTHWEST
AND OVER THE FORECAST AREA. LOOKS LIKE THE MAIN IVO ENERGY CENTER
IS STILL OVER BAJA...BUT ITS MOISTURE PLUME IS GETTING CAUGHT IN
THE UPPER JET AND IS MOVING ON UP AND INTO THE GREAT BASIN. THIS
WILL CONTRIBUTE TO THUNDERSTORM CHANCES FOR THE CWA TODAY.
WILL SEE ANOTHER ROUND OF HOT TEMPS FOR EASTERN PORTIONS OF THE
FORECAST AREA TODAY WHERE THE THERMAL RIDGE AXIS IS IN PLACE.
FURTHER WEST...WILL SEE GUSTY WEST TO SOUTHWEST WINDS ACROSS
SOUTHEAST WYOMING WHERE 700 MB WINDS WILL REMAIN BETWEEN 30 AND 35
KT THROUGH THIS AFTERNOON. THESE STRONGER WINDS WILL ADD AN
UPSLOPE COMPONENT TO THE WESTERN SLOPES...AND ALONG WITH WEAK
INSTABILITY PROGGED BY THE MODELS...LIKELY TO SEE A PRETTY GOOD
CHANCE FOR SHOWERS AND THUNDERSTORMS IN THIS AREA THROUGH THE
AFTERNOON. PWATS AROUND 150 PERCENT OF NORMAL WILL INCREASE THE
LIKELIHOOD FOR MODERATE TO HEAVY RAIN TO OCCUR OUT OF THIS
ACTIVITY AS WELL. A FEW STORMS LOOK TO DEVELOP ALONG THE CHEYENNE
RIDGE WHERE A SFC BOUNDARY LOOKS TO SET UP THROUGH THE EARLY
AFTERNOON LIKELY DUE TO DIFFERENTIAL HEATING ALONG THIS TERRAIN
FEATURE. FURTHER EAST AND NORTH ACROSS THE REMAINING PLAINS AREAS
OF SOUTHEAST WYOMING AND THE NEBRASKA PANHANDLE...CHANCES FOR
CONVECTION WILL BE LESS WITH ONLY A FEW ISOLATED STORMS EXPECTED
TO MAKE IT OFF THE HIGHER TERRAIN.
THE DEEPER MONSOONAL MOISTURE WILL SHIFT WESTWARD FOR TUESDAY
HOWEVER THE MOUNTAINS WILL REMAIN ON THE EASTERN PERIPHERY OF THIS
PLUME. THEREFORE WILL STILL SEE CHANCES FOR AFTERNOON AND EVENING
THUNDERSTORMS WITH SLIGHTLY MORE INSTABILITY PROGGED IN THIS AREA
AS WELL. A WEAK SURFACE TROUGH LOOKS TO SET UP ALONG EAST CENTRAL
WYOMING...SO WILL HAVE TO BE MINDFUL OF INITIATION OF WEAK
CONVECTION HERE AS WELL...BUT ACTIVITY WILL REMAIN ISOLATED.
OTHERWISE...TUESDAY WILL BE ANOTHER HOT DAY FOR MUCH OF THE REGION
BUT WITH LESS WIND.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 330 AM MDT MON AUG 26 2013
THE 00Z NWP GUIDANCE SHOWS THE LARGE SCALE UPPER RIDGE AXIS
RETROGRADING WEST FROM THE GREAT PLAINS TOWARD THE FRONT RANGE BY
THE END OF THE WEEK AS A TROUGH DIGS SOUTH OVER THE NORTHEAST
CONUS. A WEAK UPPER LOW IS PROGGED TO MOVE FROM THE UPPER TX COAST
ACROSS WEST CENTRAL TX AND INTO THE CENTRAL PLAINS EARLY IN THE
PERIOD. THIS FEATURE WILL SERVE TO ENTRAIN SOME DRIER AIR INTO
SOUTHEAST WY AND NEB PANHANDLE. MODEL DIFFERENCES BECOME APPARENT
THIS WEEKEND AS THE ECMWF BUILDS THE UPPER RIDGE NORTHWEST INTO
BRITISH COLUMBIA WITH AN EASTERN PACIFIC UPPER LOW HELD AT BAY.
THE GFS MAINTAINS THE UPPER RIDGE OVER THE GREAT PLAINS WITH THE
UPPER LOW MOVING ASHORE INTO THE PACIFIC NORTHWEST. BOTH MODELS
DEPICT A SHORTWAVE MOVING NORTHEAST ACROSS WY ON SUNDAY.
DIURNAL CONVECTIVE DEVELOPMENT THROUGH LATE WEEK WILL FAVOR THE
MOUNTAINS WITH THE PLAINS REMAINING DRY UNDER THE INFLUENCE OF
THE UPPER RIDGE. A PACIFIC COLD FRONT MAKES EASTWARD PROGRESS
THROUGH MONTANA AND THE DAKOTAS LATE FRIDAY INTO SATURDAY AND
INTO THE WESTERN NEB PANHANDLE AND NORTHEAST WY BY SUNDAY.
PRECIPITABLE WATER VALUES RISE TO AROUND AN INCH THIS WEEKEND.
THE COMBINATION OF THE FRONT...SHORTWAVE AND ADDITIONAL MONSOON
MOISTURE MAY YIELD GREATER CONVECTIVE COVERAGE...INCLUDING THE
PLAINS. 700MB TEMPERATURES PEAK NEAR 17C THURSDAY AND FRIDAY WITH
HIGHS IN THE UPPER 80S TO UPPER 90S. THEY LOWER A FEW DEGREES
THIS WEEKEND WITH HIGHS IN THE LOWER 80S TO LOWER 90S SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY MORNING)
ISSUED AT 1059 AM MDT MON AUG 26 2013
DO BELIEVE THUNDERSTORM CHANCES WILL BE MAINLY CONFINED TO THE
SOUTHERN LARAMIE RANGE AS WELL AS THE KLAR AND KCYS AERODROMES
THIS AFTERNOON. LATEST HRRR COMPOSITE REFLECTIVITY FORECAST
SHOWING THIS AREA THE PRIME AREA TODAY. SO...WENT AHEAD AND ADDED
TEMPO THUNDERSTORMS IN THE KLAR AND KCYS TAFS. VFR OTHERWISE WITH
CONVECTION ENDING SHORTLY AFTER 00Z.
&&
.FIRE WEATHER...
ISSUED AT 500 AM MDT MON AUG 26 2013
A VERY BROAD AND STRONG UPPER LEVEL RIDGE WILL KEEP HOLD OF THE
CENTRAL UNITED STATES THIS WEEK. SOUTHWEST FLOW WILL BE OVER THE
DISTRICT IN THIS PATTERN...WITH HOT AND MOSTLY DRY CONDITIONS
ANTICIPATED FOR THE EASTERN PLAINS AND CHANCES FOR SHOWERS AND
THUNDERSTORMS FOR THE MOUNTAINS UNDER A MODEST MONSOONAL STREAM.
THE BEST CHANCE FOR WETTING RAINS WILL BE TODAY WITH THE BEST
AVAILABLE MOISTURE IN PLACE...AND THE DEEPEST MOISTURE WILL
STEADILY SHIFT WESTWARD THROUGH THE WEEK DIMINISHING CHANCES
OVERALL. SURFACE WINDS WILL ALSO BE ON THE GUSTY SIDE TODAY ACROSS
SOUTHEAST WYOMING...WITH WIDESPREAD GUSTS FROM THE WEST-SOUTHWEST
AT 20 TO 30 MPH. AREAS WITHIN THE WIND CORRIDOR ALONG AND WEST OF
THE LARAMIE RANGE COULD SEE GUSTS AS HIGH AS 40 MPH EARLY THIS
AFTERNOON. MINIMUM HUMIDITIES WILL STAY ABOVE CRITICAL THRESHOLDS
THOUGH...WITH VALUES ROUGHLY BETWEEN 20 AND 40 PERCENT EXPECTED
TODAY. WINDS WILL BE LESS EACH AFTERNOON FOR THE REMAINDER OF THIS
WEEK...WITH MINIMUM HUMIDITIES LOOKING TO STAY BETWEEN 20 AND 30
PERCENT EACH AFTERNOON.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...RJM
LONG TERM...JAMSKI
AVIATION...CLAYCOMB
FIRE WEATHER...RJM
AREA FORECAST DISCUSSION
NWS TUCSON AZ
910 PM MST TUE AUG 27 2013
.SYNOPSIS...ADDITIONAL MOISTURE WILL PUSH UP FROM THE SOUTH STARTING
WEDNESDAY...WITH OCCASIONAL IMPULSES IN THE SOUTHERLY FLOW BRINGING
A GOOD CHANCE OF THUNDERSTORMS THE SECOND HALF OF THE WEEK.
&&
.DISCUSSION...KEMX WSR-88D DETECTED ISOLATED MOSTLY LESS THAN 40 DBZ
ECHOES ACROSS SWRN COCHISE COUNTY AT 0405Z. MOVEMENT OF THESE CELLS
WAS TO THE WEST AROUND 10 KTS. THE REST OF SE AZ WAS VOID OF PRECIP
ECHOES AT THIS TIME. IR SATELLITE IMAGERY INDICATED CLOUD TOPS
WARMING ACROSS WRN PIMA COUNTY. MID-LEVEL CLOUDS WERE EXPANDING IN
COVERAGE ACROSS MUCH OF COCHISE/SRN GRAHAM COUNTIES.
BASED ON RADAR TRENDS AS WELL AS SEVERAL RUC HRRR SOLUTIONS...HAVE
REDUCED POPS ACROSS MUCH OF SE AZ FOR THE REST OF TONIGHT. THE BEST
CHANCE FOR SHOWERS AND THUNDERSTORMS UNTIL AROUND MIDNIGHT WILL BE
NEAR THE INTERNATIONAL BORDER ADJACENT SWRN COCHISE AND SANTA CRUZ
COUNTIES. ISOLATED SHOWERS MAY MOVE INTO FAR SERN SECTIONS AROUND
DAYBREAK WED AS PER THE RUC HRRR SOLUTIONS.
OTHERWISE...EXPECT INCREASING MOISTURE ALONG WITH AN INCREASED
CHANCE OF SHOWERS/TSTMS STARTING WED. PLEASE REFER TO THE PREVIOUS
DISCUSSION SECTION BELOW FOR ADDITIONAL DETAIL.
&&
.PREV DISCUSSION /209 PM MST TUE AUG 27 2013/...MODELS CONTINUE TO
SHOW THE LARGE AREA OF HIGH PRESSURE CENTERED OVER MISSOURI WITH A
TROUGH OFF THE COAST OF THE PACIFIC NORTHWEST. BETWEEN THESE TWO
SYSTEMS...SOUTH TO SOUTHEAST FLOW ALOFT RESIDES ACROSS SOUTHERN
ARIZONA. MODELS INDICATE THAT AN INVERTED TROUGH OVER NORTHEAST
MEXICO WILL LIFT TO THE NORTHWEST AND MAKE ITS WAY INTO EXTREME
SOUTHEAST ARIZONA BY EARLY WEDNESDAY MORNING AND WILL PUSH EVEN
FARTHER INTO THE STATE THROUGHOUT THE DAY ON THURSDAY AND INTO
WESTERN ARIZONA/SRN CALIFORNIA BY LATE FRIDAY/EARLY SATURDAY WITH
SOME TIMING DIFFERENCES DEPENDING ON MODEL CHOICE/PREFERENCE.
AT ANY RATE...THE MODELS DO SHOW A SIGNIFICANT INCREASE IN MOISTURE
WITH THIS SYSTEM WITH MODEL PW`S SHOWING VALUES ABOVE THE TWO INCH
MARK FOR THE WESTERN DESERTS OF PIMA COUNTY...MORE SPECIFICALLY NEAR
AJO AND ORGAN PIPE BY LATE WEDNESDAY AND INTO THURSDAY. FARTHER EAST
TOWARD TUCSON...VALUES NOT QUITE AS HIGH...BUT A RESPECTABLE 1.6 -
1.75 INCHES NOT OUT OF THE QUESTION. AS A RESULT OF THE FORCING
PROVIDED BY THE APPROACHING INVERTED TROUGH...ALONG WITH A
SUBSTANTIAL MOISTURE INCREASE...EXPECT TO SEE A CONSIDERABLE UPSWING
IN ACTIVITY BEGINNING WEDNESDAY AFTERNOON AND CONTINUING THROUGH
FRIDAY...ALTHOUGH FAVORED AREAS FOR CONVECTION WILL LIKELY BE ALONG
THE INTERNATIONAL BORDER...AS WELL AS AREAS TO THE WEST AND
NORTHWEST OF TUCSON...BUT ALSO THE WHITE MOUNTAINS OF NORTHERN
GREENLEE COUNTY.
AFTER FRIDAY EXPECTING A DOWNSWING IN ACTIVITY AS THE HIGH PRESSURE
SYSTEM OVER THE MID MISSISSIPPI RIVER VALLEY RETROGRADES TO A
POSITION OVER COLORADO/NEW MEXICO BY THIS WEEKEND. HOWEVER...STILL
ENOUGH LINGERING MOISTURE AROUND FOR A LOW GRADE MONSOON POP
FORECAST.
HIGHS WEDNESDAY GENERALLY NEAR NORMAL...THEN 5 TO 7 DEGS BELOW NORMAL
FOR THURSDAY AND FRIDAY. THEREAFTER...HIGHS NEAR OR SLIGHTLY BELOW
NORMAL EACH DAY. LOWS GENERALLY 2 TO 3 DEGS ABOVE NORMAL EACH
MORNING.
&&
.AVIATION...ISOLD -TSRA/-SHRA MOSTLY NEAR THE INTERNATIONAL BORDER
THE REST OF TONIGHT. SCT TSRA/SHRA WILL DEVELOP BY MID-MORNING
WEDNESDAY AND CONTINUE THRU WEDNESDAY EVENING OR 29/06Z. CLOUD BASES
MOSTLY ABOVE 12K FT AGL THE REST OF TONIGHT...THEN CLOUD DECKS
AROUND 7-11K FT AGL WEDNESDAY AND WEDNESDAY EVENING. SURFACE WIND
GENERALLY ELY/SELY 5-15 KTS WITH OCCASIONAL GUSTS TO 20 KTS WILL
PREVAIL THRU WEDNESDAY EVENING. AVIATION DISCUSSION NOT UPDATED
FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...EXPECT SCATTERED SHOWERS AND THUNDERSTORMS TO
CONTINUE INTO EARLY NEXT WEEK. GUSTY AND ERRATIC WINDS WILL OCCUR
WITH THE STRONGER THUNDERSTORMS. 20-FOOT WINDS WILL BE EAST TO
SOUTHEAST AROUND 5 TO 15 MPH THROUGH THURSDAY. THEREAFTER...NORMAL
DIURNAL WIND TRENDS WILL RETURN BY THIS WEEKEND.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
DISCUSSION...FRANCIS
PREVIOUS DISCUSSION...MOLLERE
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
346 AM EDT WED AUG 28 2013
.SYNOPSIS...
WEAK LOW PRESSURE OVER THE LOWER GREAT LAKES WILL TURN SOUTHEASTWARD
AND IT SHOULD PASS OFF THE VIRGINIA COAST LATE TONIGHT. WEAK HIGH
PRESSURE FROM THE NORTHWEST AND NORTH IS ANTICIPATED TO FOLLOW FOR
THURSDAY THROUGH SATURDAY. A WARM FRONT APPROACHING FROM THE
SOUTHWEST WILL LIFT THROUGH OUR REGION ON SUNDAY OR SUNDAY NIGHT
WITH A COLD FRONT FROM THE NORTHWEST EXPECTED TO ARRIVE ON MONDAY
NIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
EARLY THIS MORNING...ESTF UPDATE AT 1230 AM CONTINUED WITH THE 1115
PM TUESDAY UPDATE WITH A LITTLE FOG INTO NNJ WITH LESS
SKYCOVER...LIGHT WIND RADIATION COOLING CONDITION IN NJ.
ISOLATED SHOWERS NOW DEVELOPING AND ENTERING BERKS COUNTY TO THE NW
OF KRDG AT 305 AM.
TODAY...LOOKING LIKE A HEAVY RAIN EVENT FOR PTNS SE PA THRU THE
DELMARVA OR SNJ VCNTY KRDG-KPHL-KACY SWWD WITH 21Z/27 SREF PROBS FOR
1 INCH OF RAIN...PWAT BUILDING TO 2.1 INCHES OVER DELMARVA...SLOW -
10 KT - NW-W STEERING CURRENTS AND A SHORT WAVE LIFTING MOISTURE
OVER A SHALLOW CONVERGENCE ZONE NEAR SFC LOW PRES SOMEWHERE OVER E
MD DE. WHILE SVR TSTMS ARE UNLIKELY DUE TO WEAK SHEAR AND TT UNDER
48C...GULLY WASHERS ARE LIKELY WITH KI IN THE MID 30S THIS AFTN
THERE...SWI NEAR -2 AND A NEAR 90F AIRMASS IN THE WARM SECTOR. ML
CAPE WILL BE NEAR 1400J WHERE AND WHEN ITS NOT INITIALLY NOT RAINING
DURING MIDDAY. LIGHT WIND.
THE 00Z/28 RGEM/GGEM LOOK TOO FAR NORTH WITH THEIR FCST QPF
BULLSEYES.
THIS FCST IS A 50 50 BLEND OF THE GFS/NAM ELEMENTS WITH SOME RGEM IN
THE SKYCOVER PTN OF THE FCST. NO SREF INPUT INTO THE POP BUT THE
NEAR TERM PTN OF THIS FCST HAS A RELIANCE ON THE RAP MODEL GUIDANCE
AS SEEN IN THE CONSTANTLY MODEL UPDATED COSPA PRODUCT.
HPCQPF 06Z GRIDS WERE USED...WHICH FORCED THE BOX WX TOOL WORDING OF
HEAVY RAIN POSSIBLE FROM JUST SW OF KPHL S AND WEST TODAY.
FOR THUNDER...USED THE KI 36 (BLENDED 00Z/28 NAM/GFS KI) FOR
THUNDER. THAT KEEPS THUNDER LIMITED INLAND.
WE DID REVIEW THE 00Z/28 SPCWRF FOR TIMING CONVECTION AND ALSO THE
NSSL WRF QPF FCST (TTN-CMAY AXIS WHICH LOOKS TOO FAR NE BUT ISOLATED
3 INCH AMTS).
NO FLASH FLOOD WATCH. HOURLY FFG OVER 2.5 INCHES AND 6 HRLY IS
GENERALLY OVER 4.5 INCHES. MY CONCERN WITH RESPECT TO FFG...CHESTER
COUNTY PA AND NEW CASTLE DE. HOWEVER THAT DOESNT RULE OUT OTHER
COUNTIES. ITS WHERE ANY TSTMS REPEAT OR ARE QSTNRY THIS AFTN.
CONFIDENCE: AVERAGE
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
LEFTOVER CONVECTION DURING THE EVENING...MAINLY TO THE S OF KPHL.
THEN FOG AND STRATUS OVERNIGHT WITH POTENTIAL FOR 1/4MI DENSE FOG IN
PLACES WITH LIGHT WIND AND CLEARING ALOFT LEAVING THE MOIST BL
EXPOSED TO SATURATION. USED THE UPS CROSSOVER TOOL FOR FOG AFTER
06Z.
CONFIDENCE: ABOVE AVERAGE.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
ALOFT...THE PERIOD STARTS OFF WITH A NORTHWEST FLOW. AS THE BIG
RIDGE TO OUR WEST BECOMES SUPPRESSED ON SATURDAY, THE FLOW OVER THE
MID-ATLANTIC BECOMES MORE WESTERLY. THE FLOW TURNS MORE
SOUTHWESTERLY ON MONDAY AND TUESDAY AS A TROF MOVES THROUGH.
AT THE SURFACE...WEAK HIGH PRESSURE WILL BE IN PLACE THURSDAY THROUGH
SATURDAY. A WARM WILL MOVE THROUGH ON SUNDAY. A COLD FRONT WILL
FOLLOW ON MONDAY NIGHT.
PRECIPITATION...LOTS OF SMALL POPS(20/30%) THROUGH SUNDAY WITH THE
HIGHEST POPS ACROSS THE I-95 CORRIDOR WESTWARD AND DURING THE
AFTERNOON AND EVENING. WITH A COLD FRONT APPROACHING ON MONDAY AND
MOVING THROUGH MONDAY NIGHT, POPS ARE EVENLY DISTRIBUTED.
EVEN THOUGH WEAK HIGH PRESSURE IS IN PLACE, MODELS HAVE BEEN PUSHING
PRECIP ACROSS THE INTERIOR LATE THIS WEEK AND INTO THE WEEKEND FOR A
COUPLE DAYS. WITH WEAK S/W`S MOVING ACROSS THE TOP OF US COMBINED
WITH AFTERNOON INSTABILITY AND SHALLOW MOISTURE CONVERGENCE, IT
SEEMS REASONABLE. THE ONLY REAL CHANGE I MADE IN THE GRIDS THIS
MORNING WAS TO FOCUS MORE ON THE INTERIOR. THOSE VISITING THE
BEACHES MAY NOT SEE A DROP. AND THOSE FURTHER INLAND, THE FORECAST
WILL SOUND WETTER THAN REALITY.
TEMPERATURES...AROUND NORMAL THROUGH MONDAY. SLIGHTLY BELOW NORMAL
ON TUESDAY.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
EARLY THIS MORNING PRIOR TO 12Z...VFR WITH SCT-BKN CLOUDS AOA 5000
FT DEVELOPING. PATCHY MVFR OR IFR FOG POSSIBLE NEW JERSEY WHERE BEST
RADIATIONAL COOLING. SHOWERS DEVELOPING VCNTY KRDG AROUND 0715Z.
LIGHT WIND. CONFIDENCE: AVERAGE
TODAY AFTER 12Z...VFR CIGS OVERSPREADING THE AREA. ANY MORNING
FOG WILL BURN OFF BY 14Z. LIGHT WIND. SHOWERS AND SCT TSTMS
EXPECTED MOST TAF SITES FOR 1-4 HOURS. MOST LIKELY AREA FOR TSTMS
IS VCNTY KRDG-KPHL-KILG-KMIV. THE 06Z TAFS HAVE 3SM MDT SHOWERS
WHERE MY CONFIDENCE IS GREATEST FOR CONVECTION BUT NO MENTION OF
TSTM ATTM DESPITE MY EXPECTATION THAT KRDG/KPHL/KILG WILL RECORD A
TSTM TODAY. CONFIDENCE ON DETAILS: AVERAGE.
TONIGHT...VFR CIGS OR MVFR CONDS IN FOG/SCT SHOWERS AND ISO TSTMS
DIMINISHING EARLY WITH IFR CONDS IN ST/FOG APPEARING LIKELY LATE
FOR MOST TAF SITES. 21Z/27 SREF PROBS FOR THIS IFR OCCURRENCE ARE
ABOUT 40-50 PCT FOCUSED ON KMIV-KPHL AXIS. CONFIDENCE ON CIGS/VSBY
EARLY IS BELOW AVG. CONFIDENCE ON SOME SORT OF IFR IN FOG/STRATUS
LATE .. AFTER 06Z...IS ABOVE AVERAGE.
OUTLOOK...
THURSDAY...MAINLY VFR. THERE IS A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS ON THURSDAY AFTERNOON.
THURSDAY NIGHT...MAINLY VFR WITH LATE NIGHT AND EARLY MORNING
VISIBILITY RESTRICTIONS POSSIBLE.
FRIDAY...MAINLY VFR. THERE IS A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS ON THURSDAY AFTERNOON.
FRIDAY NIGHT...MAINLY VFR WITH LATE NIGHT AND EARLY MORNING
VISIBILITY RESTRICTIONS POSSIBLE.
SATURDAY THROUGH SUNDAY...MAINLY VFR WITH LATE NIGHT AND EARLY
MORNING VISIBILITY RESTRICTIONS POSSIBLE. THERE IS A CHANCE OF
MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS.
&&
.MARINE...
NO HEADLINES THROUGH TONIGHT.
ATLC SEAS WILL CONTINUE TO RUN AROUND 2-3 FEET.
LIGHT AND VARIABLE WINDS TREND SOUTHERLY OR SOUTHEASTERLY DURING
THE DAY THEN EVENTUALLY NE TONIGHT.
NE GUSTS 15-20 KT POSSIBLE S NJ AND DE COASTS NEAR DAYBREAK
THURSDAY.
OUTLOOK...
WEAK HIGH PRESSURE CAN BE EXPECTED THURSDAY THROUGH SATURDAY. A WARM
FRONT WILL MOVE ACROSS THE WATERS FROM THE SOUTHWEST ON SUNDAY. WIND
SPEEDS AND WAVE HEIGHTS ARE EXPECTED TO REMAIN BELOW THE SMALL CRAFT
ADVISORY CRITERIA THROUGH THE PERIOD.
&&
.RIP CURRENTS...
TODAY...LOW RISK DOES NOT MEAN NO RISK BUT ITS BEEN A LOW RISK
SUMMER IN OUR FCST AREA SINCE THE ATLANTIC TROPICAL BASIN HAS BEEN
NOTABLY QUIET...DESPITE A FEW NAMED STORMS THAT JUST HAVENT SENT
MUCH SWELL UP OUR WAY.
THURSDAY...CURRENTLY IS OUTLOOKED LOW RISK BUT IF NE WINDS AVG 20
KT ALONG THE DE COAST...THIS COULD RESULT IN A MDT RISK THERE WITH
A HIGHER THAN MODELED SWELL. SO THERE IS RISK UNCERTAINTY FOR THURSDAY.
FRIDAY THROUGH MONDAY OUTLOOK AS LOW RISK DAYS.
&&
.CLIMATE...
TODAY`S HIGH TEMPERATURE AT PHILADELPHIA INTERNATIONAL AIRPORT
THROUGH 500 PM WAS 89 DEGREES. THIS MATCHES THE HIGH TEMPERATURE
WHICH OCCURRED BACK ON THE 21ST.
IF THE TEMPERATURE AT PHILADELPHIA DOES NOT REACH 90 DEGREES THIS
MONTH, IT WILL BE THE FIRST AUGUST SINCE 1984 WITHOUT AT 90 DEGREE
READING. IT IS RATHER UNUSUAL FOR THERE NOT BE AT LEAST ONE 90
DEGREE READING AT PHILADELPHIA DURING THE MONTH OF AUGUST. IT HAS
HAPPENED ONLY 5 TIMES OVER THE PAST CENTURY, IN 1920, 1927, 1934,
1963 AND 1984.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KRUZDLO
NEAR TERM...DRAG
SHORT TERM...DRAG
LONG TERM...KRUZDLO
AVIATION...DRAG/KRUZDLO
MARINE...DRAG/KRUZDLO
RIP CURRENTS...DRAG
CLIMATE...IOVINO
AREA FORECAST DISCUSSION...UPDATED
NWS MIAMI FL
125 AM EDT WED AUG 28 2013
.AVIATION...
THE WINDS WILL BE LIGHT AND VARIABLE THROUGH THE EARLY MORNING
HOURS BEFORE INCREASING TO 5 TO 10 KNOTS FROM THE EAST LATE THIS
MORNING INTO THIS AFTERNOON FOR MOST OF SOUTH FLORIDA TAF SITES.
THE ONLY EXCEPTION TO THIS IS AT KAPF TAF SITE WHERE THE WINDS
WILL BECOME WESTERLY AFTER 17Z TODAY...DUE TO THE WEST COAST SEA
BREEZE PUSHING INLAND.
THERE SHOULD BE SHOWERS AROUND LATE THIS MORNING INTO THIS
AFTERNOON OVER ALL OF THE TAF SITES ALONG WITH A FEW THUNDERSTORMS
MAINLY AFTER 18Z. HOWEVER...THE COVERAGE OF THE THUNDERSTORMS WILL
BE SMALL OVER THE TAF SITES. SO WILL ONLY CARRY VCSH AT THIS TIME
FOR ALL OF SOUTH FLORIDA TAF SITES. THE CEILING AND VIS WILL ALSO
REMAIN IN THE VFR CONDITIONS THROUGH THIS EVENING AT ALL OF THE
TAF SITES...DUE TO THE UNKNOWN TIMING OF THE SHOWERS AND
THUNDERSTORMS AT THE TAF SITES.
&&
.AVIATION...54/BNB
.PREV DISCUSSION... /ISSUED 827 PM EDT TUE AUG 27 2013/
UPDATE...
SHOWERS AND A FEW EMBEDDED THUNDERSTORMS ASSOCIATED WITH A
PERSISTENT UPPER LEVEL LOW ACROSS SOUTH FLORIDA CONTINUE MAINLY
ACROSS THE ATLANTIC AND GULF WATERS. LATEST HRRR DEPICTS DEEPER
MOISTURE SWINGING WEST ACROSS THE ATLANTIC WATERS AND INTO THE
EAST COAST OVERNIGHT WITH A WEAK SURFACE TROUGH IN PLACE. WILL
KEEP CHANCE POP OVERNIGHT FOR THE EAST COAST METRO AREAS.
AVIATION...
WEATHER OVER SOUTH FLORIDA WILL CONTINUE TO BE DOMINATED BY MAINLY
MID-LEVEL LOW PRESSURE CENTERED OVER FLORIDA STRAITS...WHICH WILL
DRIFT WESTWARD FOR NEXT 24-36 HOURS. THIS MEANS MOIST EASTERLY FLOW
WILL PREVAIL...AT SPEEDS OF 5 TO 10 KTS AT THE SURFACE. SCATTERED
SHOWERS AND A FEW THUNDERSTORMS ARE EXPECTED ACROSS EASTERN
TERMINALS EVEN DURING THE OVERNIGHT...THUS VCSH TAFS STARTING AT
2-4Z AND CONTINUING THROUGH TAF PERIOD. EXCEPTION IS NAPLES WHERE
POP IS AROUND 30 PERCENT FOR TONIGHT AND WEDNESDAY. TEMPO THUNDER
GROUP PLACED IN PBI TAF DUE TO CLUSTER OF STORMS APPROACHING FROM
ATLANTIC AT 0Z.
&&
PREV DISCUSSION... /ISSUED 254 PM EDT TUE AUG 27 2013/
DISCUSSION...
THE MODEL TRENDS THE LAST COUPLE OF DAYS HAVE EMPHASIZED A CUT-
OFF MID TO UPPER LEVEL LOW FORECAST TO LINGER ACROSS THE REGION
THROUGH THE EARLY PART OF THE WEEK AND THEN A DRYING TREND DURING
THAT PERIOD. HOWEVER...THE LATEST GUIDANCE CONTINUES TO SUGGEST
THAT THE MID TO UPPER LEVEL LOW WILL LIKELY CONTINUE THROUGH THE
REMAINDER OF THE WEEK AND POSSIBLY INTO THE WEEKEND. IN ADDITION
THE LATEST GUIDANCE SUGGESTS THAT THE DRYING TREND WILL BE DELAYED.
FOR TONIGHT...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE
FORECAST TO CONTINUE MAINLY ACROSS THE SOUTHERN AND EASTERN
PORTIONS OF THE PENINSULA WITH THE MORE NUMEROUS ACTIVITY EXPECTED
ACROSS THE SOUTHERN PORTION OF THE PENINSULA AND ADJACENT GULF
AND ATLANTIC WATERS.
THE LOW LEVEL FLOW AT THE 850 HPA LEVEL IS FORECAST TO BECOME MORE
SOUTHERLY TONIGHT INTO WEDNESDAY AND WILL MAINTAIN DEEPER LAYERED
MOISTURE ACROSS THE REGION. FORECAST SOUNDINGS INDICATE FORECAST
PWAT AROUND 1.9 INCHES ON WEDNESDAY. THE LINGERING UPPER LEVEL LOW
AND COOLER MID LEVELS WILL CONTINUE TO ALLOW FOR A CHANCE OF
AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS ON WEDNESDAY. ON
THURSDAY AND FRIDAY THE UPPER LEVEL LOW IS FORECAST TO LINGER
ACROSS THE REGION AND WILL ALSO ADD TO THE UNCERTAINTY OF THE
FORECAST. ALTHOUGH MAINLY ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS ARE FORECAST THURSDAY AND FRIDAY...THERE WILL BE
SUFFICIENT LINGERING MOISTURE THAT MORE MORE WIDE SPREAD COVERAGE
IS POSSIBLE DEPENDING ON THE POSITION OF THE UPPER LOW. WILL HAVE TO
WAIT AND SEE HOW THE MODELS HANDLE THE EVOLUTION OF THE UPPER LOW
FOR THE LATER PART OF THE WEEK INTO THE WEEKEND.
MARINE...
A WEAK PRESSURE GRADIENT AND LIGHTER AND AT TIMES VARIABLE WINDS
TO 10 KNOTS OR LESS ARE FORECAST ACROSS THE REGIONAL WATERS
THROUGH MOST OF THE FORECAST PERIOD WITH MOSTLY TRANQUIL SEAS
FORECAST THROUGH THE FORECAST PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 77 91 79 92 / 20 20 20 20
FORT LAUDERDALE 78 90 80 93 / 20 20 20 20
MIAMI 77 91 78 93 / 20 20 20 20
NAPLES 76 89 76 91 / 20 20 20 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...60/BD
AVIATION/RADAR...59/RM
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
255 AM CDT WED AUG 28 2013
.DISCUSSION...
915 PM CDT
SOME SMALL CHANGES MADE TO THE GOING FORECAST THIS EVE. HAVE
CONFINED THE POPS IN IL MORE TO JUST FAR NORTHEAST IL MOVING THEM
EAST OF ROCKFORD. HAVE ALSO BUMPED UP CLOUD COVER WEDNESDAY
MORNING IN NORTHEAST IL AND NORTHWEST IN AND SLOWED THE MORNING
TEMPERATURE CLIMB...NAMELY NEAR THE LAKE MI SHORE INCLUDING
DOWNTOWN CHICAGO.
CONTINUE TO MONITOR CONVECTIVE BEHAVIOR OVER EASTERN AND CENTRAL
WISCONSIN AS WE MOVE THROUGH THE LATE EVE INTO THE OVERNIGHT.
STORMS HAVE BEEN FIRING SINCE MID-AFTERNOON ALONG THE ELONGATED
SURFACE BOUNDARY AND WITHIN THE PERIPHERY OF THE HEAT DOME/UPPER
RIDGE AND PWAT MAX /AROUND TWO AND A QUARTER ON 00Z GRB SOUNDING/.
THESE HAVE SLOWLY EVOLVED SOUTHEASTWARD FEEDING ON INSTABILITY AND
THE EDGE OF THE CAP AND MOVING WITHIN THE MEAN NW MID-LEVEL FLOW.
STORM MODE ACROSS EASTERN WI HAS BEEN MAINLY DISCRETE...INCLUDING
A COUPLE SEVERE SUPERCELLS. OUTFLOWS HAVE GENERALLY MERGED THOUGH
PER THE GRB RADAR AND OBSERVATIONS...AND THE MOST PRONOUNCED AND
FURTHEST SOUTH ONE IS APPROACHING AT AROUND 20 KT. WHILE THERE IS
AMPLE INSTABILITY PRESENT...IT APPEARS A LOW-LEVEL INVERSION IS
DEVELOPING BASED ON AMDAR SOUNDINGS AND THE EXPANDING MKX RADAR
BLOOM. SO POTENTIAL FOR NEW CONVECTION ALONG THIS OUTFLOW MAY BE
WANING...AS MAY BE THE FORWARD PROPAGATION SPEED UNLESS SOME NEW
CONVECTION DEVELOPS. STILL SOME POTENTIAL FOR THE ADJACENT LAKE MI
AREAS TO BE CLIPPED GIVEN RAP FORECAST CORFIDI VECTOR STORM
MOTIONS...AND ESPECIALLY IF STORMS AND ASSOCIATED OUTFLOWS PICK UP
PACE SOUTHWARD OVER THE LAKE. THERE WOULD BE SOME WIND POTENTIAL
WITH THESE...BUT OVERALL RADAR TRENDS IN THE PAST HALF HOUR
UPSTREAM POINT TOWARD ANY STRONG STORM POTENTIAL DROPPING QUICKLY.
GIVEN THE PHASED OUTFLOWS IT DOES LOOK LIKE THE SURFACE WIND
SHIFT TO N/NE MAY OCCUR EARLIER THAN ORIGINALLY THOUGHT IN
NORTHEAST IL...WHICH MEANS ADVECTION OF THE MARINE LAYER OVER
LAND TO OCCUR MORE DURING NIGHT. THE 00Z NAM IS MORE PESSIMISTIC
THAN ITS PREDECEASING RUN WITH A MOISTENING LOW-LEVEL INVERSION AND
CLOUDS...AND THAT AGREES WITH THE RAP. THIS MAKES SENSE NOT
NECESSARILY GIVEN CLIMATOLOGY FOR LATE AUG BUT CLIMATOLOGY GIVEN
THE SYNOPTIC SITUATION AND UPSTREAM OBS OF CIGS BEHIND THE FRONT.
WHILE THERE IS POTENTIAL FOR FOG TOO FROM THE MARINE
LAYER...FORECAST SOUNDINGS WOULD INDICATE MORE FAVORED STRATUS AND
THAT HAS BEEN THE OBSERVATIONAL TREND THUS FAR. SO HAVE SLOWED
THE MORNING TEMPERATURE CLIMB OVER CHICAGO AND FAR NW IN BUT NOT
ADJUSTED HIGHS AT THIS POINT.
MTF
//PREV DISCUSSION...
252 PM CDT
LATE SEASON HEAT HAS DEVELOPED THIS AFTERNOON ACROSS NORTHERN
IL/NORTHWEST IN WITH TEMPS PUSHING INTO THE MID 90S...WITH A FEW
AREAS TOUCHING THE UPR 90S. THIS COUPLED WITH DEW POINTS HOLDING
AROUND 70 DEGREES HAS RESULTED IN HEAT INDEX VALUES BETWEEN 98-105
IN SEVERAL LOCATIONS. THE HEAT ADVISORY HAS REMAINED IN PLACE
ACROSS LEE/OGLE/DEKALB/BOONE/WINNEBAGO COUNTIES.
THE MAIN CHALLENGE FOR THIS EVENING THROUGH THE OVERNIGHT WILL BE ON
POSSIBLE CONVECTION WITH A FEW STRONG STORMS DEVELOPING ALONG A
BOUNDARY...WHICH IS PROGGED TO BE SLIDING SOUTHEAST ACROSS WISCONSIN
INTO NORTHEAST IL/NORTHWEST IN. THE CHANNEL OF BETTER ATMOSPHERIC
MOISTURE WAS ORIENTED FROM THE HIGH PLAINS STRETCHING EAST THROUGH
THE UPPER MIDWEST THEN BENDING SOUTHEAST THROUGH THE GREAT LAKES
REGION THIS AFTERNOON. THIS APPEARS TO FIT WELL ALONG THE PROGGED
586-590 HEIGHT CONTOUR...WHICH APPEARS TO REMAIN NEARLY STATIONARY
THROUGH THE NEXT 24 HOURS. THIS AFTERNOON THE BOUNDARY WAS
POSITIONED ACROSS THE UPPER MIDWEST THROUGH THE UPPER PENINSULA OF
MICHIGAN...WHICH IS EXPECTED TO BE THE FOCAL POINT FOR CONVECTIVE
GENERATION LATER THIS AFTERNOON. CURRENT TIMING OF ARRIVAL INTO
NORTHERN IL CONTINUES TO BE JUST AFT 00Z...WITH THE PEAK BETWEEN
03-06Z. WITH THE VERY WARM SFC CONDITIONS THIS AFTN...POTENTIAL
ENERGY WILL LIKELY REMAIN ELEVATED UPON ARRIVAL OF
CLOUDS/CONVECTION...WHICH COULD FURTHER ENHANCE THUNDERSTORMS TO
POSSIBLY REACHING SEVERE LIMITS.
THE LOCATION OF GREATEST CONCERN WILL LIKELY BE ALONG AND NORTHEAST
OF A ROCKFORD TO KANKAKEE LINE...WITH THE MAIN HAZARDS FROM
THUNDERSTORMS BEING BRIEF HEAVY DOWNPOURS/WIND GUSTS TO 60MPH/HAIL
UP TO 1".
AS THE BOUNDARY SLIDES SOUTH ACROSS THE CWFA AFTER MIDNIGHT...WINDS
WILL TURN NORTH/NORTHEAST. LLVL MOISTURE APPEARS TO LINGER THRU
DAYBREAK WED. OVERNIGHT LOWS WILL REMAIN MILD ONE MORE NIGHT IN THE
LOW 70S...TO MID 70S CLOSER TO DOWNTOWN CHICAGO.
WEDNESDAY...
MID-LVL RIDGE CENTER WILL DRIFT SOUTHWEST...ALLOWING HEIGHTS TO
WEAKEN MARGINALLY OVER THE WESTERN GREAT LAKES REGION. GUIDANCE
CONTINUES TO PROG A WEAK WAVE SLIDING ACROSS THE NORTHERN CWFA WED
MORNING...WHICH ALONG WITH THE LINGERING LLVL MOISTURE COULD
TRANSLATE INTO POSSIBLE SHRA/TSRA WED MORNING FOR THE
CENTRAL/SOUTHERN CWFA. AT THIS TIME HAVE MAINTAINED A DRY FORECAST
FOR WED AS ANTI-CYCLONIC FLOW SHOULD SLOWLY SLIDE SOUTH ACROSS THE
LAKES AND STEADILY DRY THE SFC. NORTHEAST LLVL FLOW WILL CONTINUE TO
USHER IN DRIER AIR...WITH SLIGHTLY COOLER TEMPS ALONG THE LAKESHORE
COMMUNITIES. TEMPS FOR FAR NORTHEAST IL/NORTHWEST IN WILL HOVER IN
THE LOW/MID 80S...MEANWHILE FURTHER INLAND TEMPS WILL WARM INTO THE
UPR 80S TO POSSIBLY LOWER 90S ALONG AND SOUTH OF A LASALLE TO
KANKAKEE LINE.
CONFIDENCE...HIGH.
THURSDAY THROUGH LABOR DAY...
CONSIDERABLE CHANGES HAVE TAKEN PLACE IN THE FINAL PERIODS OF THE
EXTENDED...HOWEVER MODEL SPREAD DOES APPEAR TO HAVE DIMINISHED
MARGINALLY WITH RESPECT TO HIGH TEMPS FOR THE HOLIDAY WEEKEND.
ENSEMBLES CONTINUE TO DEMONSTRATE NOISE WITH A WIDE RANGE OF
SOLUTIONS BEYOND FRI. GUIDANCE DOES CONTINUE TO SHOW MID-LVL RIDGE
INFLUENCING THE WEATHER FOR THE WESTERN GREAT LAKES
THUR/FRI...HOWEVER WITH THE CWFA REMAINING ALONG THE NORTHEAST
PERIPHERY OF THE RIDGE...THE PROBABILITY OF ANY WAVES GENERATING
CLOUDS/CONVECTION IS INCREASED FOR THE AREA. CURRENT THINKING IS
THAT SFC RIDGE FROM WED WILL REMAIN IN PLACE THRU THUR THEN BEGIN TO
DRIFT SOUTHEAST THUR NIGHT. THIS WILL BRING THE NEXT CHC FOR
SHRA/TSRA TO THE CWFA THUR NIGHT INTO FRI...LINGERING THRU SAT
BEFORE BEGINNING TO DRY BACK OUT FOR SUN AND LABOR DAY.
ECMWF/GFS HAVE CONTINUED TO PROG A TROUGH DEVELOPING OVER THE
CANADIAN ROCKIES FRI AND PUSHING OVER THE GREAT LAKES REGION SUN.
WITH THE NOW EXPECTED TROUGHING EXPECTED ACROSS THE REGION FOR THE
SECOND HALF OF THE WEEKEND...TEMPS WILL LIKELY SWING IN THE COOLER
DIRECTION WITH HIGHS IN THE UPR 70S TO POSSIBLY MID 80S FOR LABOR
DAY.
CONFIDENCE...MEDIUM.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* WINDS BCMG NORTH EARLY THIS MORNING AND THEN NE SHORTLY THERE
AFTER.
* MVFR TO IFR CIGS ARE PSBL EARLY THIS MORNING.
* MVFR VSBY IS PSBL LATE TONIGHT INTO THURSDAY MORNING.
JEE
//DISCUSSION...UPDATED 06Z...
A BROAD AREA OF LOW PRESSURE STRETCHES FROM LAKE ONTARIO THROUGH
SOUTHERN WI WITH THE LOWS COLD FRONT FROM SAGINAW MI TO LA CROSSE
WI. THE FRONT WILL CONTINUE TO SINK SOUTH REACHING THE TERMINALS
EARLY THIS MORNING. WINDS WILL BECOME NORTH BEHIND THE FRONT AND
MVFR TO IFR CIGS MAY ACCOMPANY THE FRONTAL PASSAGE. LATEST
GUIDANCE SUGGESTS THE LOWER CIGS WILL NOT MAKE IT SOUTH OF THE
WI/IL STATE LINE AND TRENDS ON SATELLITE WOULD SUPPORT THIS TRAIN
OF THOUGHT. HOWEVER...DID NOT FEEL COMFORTABLE PULLING THE LOWER
CIGS JUST YET SO KEPT IN FEW TO SCT IFR/MVFR CIGS THIS MORNING.
ALSO THINKING VSBY WILL REMAIN VFR ABOVE 6SM THIS MORNING.
WINDS BECOME NE ARND 10 KT THIS MORNING WITH ANY LOWER CLOUD COVER
BURNING OFF BY MID AFTERNOON. ADDED IN THE POSSIBILITY OF MVFR
VSBY LATE TONIGHT AS GUIDANCE AND MODEL SOUNDINGS ARE ALL
SUGGESTING THE LOW LEVELS WILL BE RATHER SATURATED TONIGHT.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN WIND TRENDS...MEDIUM-HIGH CONFIDENCE IN TIMING.
* LOW CONFIDENCE IN MVFR/IFR CIGS. CIGS MAY REMAIN VFR THROUGH THE
PERIOD.
* MEDIUM CONFIDENCE IN REDUCED VSBY LATE TONIGHT.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
JEE
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THURSDAY...VFR.
FRIDAY...CHANCE TSRA...MAINLY FRIDAY EVENING.
SATURDAY...CHANCE TSRA.
SUNDAY...SLIGHT CHANCE TSRA.
MONDAY...VFR.
RC
&&
.MARINE...
254 AM CDT
A BROAD LOW IS OVER SOUTHERN LAKE MI AND THE LOWER MI PENINSULA AND
ITS COLD FRONT IS STRETCHED ACROSS SOUTHERN WI SINKING SOUTH. THE
FRONT WILL CLEAR THE SOUTHERN END OF THE LAKE EARLY THIS MORNING
WITH NORTH WINDS 10-20 KT EXPECTED BEHIND IT. LOW STRATUS AND FOG
HAVE ALSO BEEN REPORTED BEHIND THE FRONT...BUT EXPECTING BOTH OF
THOSE TO BURN OFF THIS MORNING. HIGH PRESSURE SETTLES IN BEHIND THE
FRONT WITH WINDS DIMINISHING AND BECOMING VARIABLE THURSDAY
AFTERNOON. THE HIGH SHIFTS EAST THURSDAY NIGHT AND WINDS BECOME
SOUTH. LOW PRESSURE CURRENTLY OVER THE CENTRAL PLAINS BEGINS TO
MOVE EAST FRIDAY WHILE A STRONGER LOW FORMS OVER SASKATCHEWAN
FRIDAY. THE PLAINS LOW MERGES WITH THE STRONGER LOW AS THE STRONGER
LOW MOVES NORTH OF THE GREAT LAKES SATURDAY NIGHT AND SUNDAY. LIGHT
WINDS TURN EAST AHEAD OF THE LOW FRIDAY NIGHT AND THEN SOUTH
SATURDAY NIGHT. THE LOWS COLD FRONT SWEEPS OVER THE LAKE SUNDAY
NIGHT WITH WINDS BECOMING NORTH BEHIND IT. GUSTS UP TO 30 KT ARE
VERY POSSIBLE BEHIND THE FRONT THROUGH MONDAY NIGHT.
JEE
&&
.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:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1251 AM CDT WED AUG 28 2013
.DISCUSSION...
915 PM CDT
SOME SMALL CHANGES MADE TO THE GOING FORECAST THIS EVE. HAVE
CONFINED THE POPS IN IL MORE TO JUST FAR NORTHEAST IL MOVING THEM
EAST OF ROCKFORD. HAVE ALSO BUMPED UP CLOUD COVER WEDNESDAY
MORNING IN NORTHEAST IL AND NORTHWEST IN AND SLOWED THE MORNING
TEMPERATURE CLIMB...NAMELY NEAR THE LAKE MI SHORE INCLUDING
DOWNTOWN CHICAGO.
CONTINUE TO MONITOR CONVECTIVE BEHAVIOR OVER EASTERN AND CENTRAL
WISCONSIN AS WE MOVE THROUGH THE LATE EVE INTO THE OVERNIGHT.
STORMS HAVE BEEN FIRING SINCE MID-AFTERNOON ALONG THE ELONGATED
SURFACE BOUNDARY AND WITHIN THE PERIPHERY OF THE HEAT DOME/UPPER
RIDGE AND PWAT MAX /AROUND TWO AND A QUARTER ON 00Z GRB SOUNDING/.
THESE HAVE SLOWLY EVOLVED SOUTHEASTWARD FEEDING ON INSTABILITY AND
THE EDGE OF THE CAP AND MOVING WITHIN THE MEAN NW MID-LEVEL FLOW.
STORM MODE ACROSS EASTERN WI HAS BEEN MAINLY DISCRETE...INCLUDING
A COUPLE SEVERE SUPERCELLS. OUTFLOWS HAVE GENERALLY MERGED THOUGH
PER THE GRB RADAR AND OBSERVATIONS...AND THE MOST PRONOUNCED AND
FURTHEST SOUTH ONE IS APPROACHING AT AROUND 20 KT. WHILE THERE IS
AMPLE INSTABILITY PRESENT...IT APPEARS A LOW-LEVEL INVERSION IS
DEVELOPING BASED ON AMDAR SOUNDINGS AND THE EXPANDING MKX RADAR
BLOOM. SO POTENTIAL FOR NEW CONVECTION ALONG THIS OUTFLOW MAY BE
WANING...AS MAY BE THE FORWARD PROPAGATION SPEED UNLESS SOME NEW
CONVECTION DEVELOPS. STILL SOME POTENTIAL FOR THE ADJACENT LAKE MI
AREAS TO BE CLIPPED GIVEN RAP FORECAST CORFIDI VECTOR STORM
MOTIONS...AND ESPECIALLY IF STORMS AND ASSOCIATED OUTFLOWS PICK UP
PACE SOUTHWARD OVER THE LAKE. THERE WOULD BE SOME WIND POTENTIAL
WITH THESE...BUT OVERALL RADAR TRENDS IN THE PAST HALF HOUR
UPSTREAM POINT TOWARD ANY STRONG STORM POTENTIAL DROPPING QUICKLY.
GIVEN THE PHASED OUTFLOWS IT DOES LOOK LIKE THE SURFACE WIND
SHIFT TO N/NE MAY OCCUR EARLIER THAN ORIGINALLY THOUGHT IN
NORTHEAST IL...WHICH MEANS ADVECTION OF THE MARINE LAYER OVER
LAND TO OCCUR MORE DURING NIGHT. THE 00Z NAM IS MORE PESSIMISTIC
THAN ITS PREDECEASING RUN WITH A MOISTENING LOW-LEVEL INVERSION AND
CLOUDS...AND THAT AGREES WITH THE RAP. THIS MAKES SENSE NOT
NECESSARILY GIVEN CLIMATOLOGY FOR LATE AUG BUT CLIMATOLOGY GIVEN
THE SYNOPTIC SITUATION AND UPSTREAM OBS OF CIGS BEHIND THE FRONT.
WHILE THERE IS POTENTIAL FOR FOG TOO FROM THE MARINE
LAYER...FORECAST SOUNDINGS WOULD INDICATE MORE FAVORED STRATUS AND
THAT HAS BEEN THE OBSERVATIONAL TREND THUS FAR. SO HAVE SLOWED
THE MORNING TEMPERATURE CLIMB OVER CHICAGO AND FAR NW IN BUT NOT
ADJUSTED HIGHS AT THIS POINT.
MTF
//PREV DISCUSSION...
252 PM CDT
LATE SEASON HEAT HAS DEVELOPED THIS AFTERNOON ACROSS NORTHERN
IL/NORTHWEST IN WITH TEMPS PUSHING INTO THE MID 90S...WITH A FEW
AREAS TOUCHING THE UPR 90S. THIS COUPLED WITH DEW POINTS HOLDING
AROUND 70 DEGREES HAS RESULTED IN HEAT INDEX VALUES BETWEEN 98-105
IN SEVERAL LOCATIONS. THE HEAT ADVISORY HAS REMAINED IN PLACE
ACROSS LEE/OGLE/DEKALB/BOONE/WINNEBAGO COUNTIES.
THE MAIN CHALLENGE FOR THIS EVENING THROUGH THE OVERNIGHT WILL BE ON
POSSIBLE CONVECTION WITH A FEW STRONG STORMS DEVELOPING ALONG A
BOUNDARY...WHICH IS PROGGED TO BE SLIDING SOUTHEAST ACROSS WISCONSIN
INTO NORTHEAST IL/NORTHWEST IN. THE CHANNEL OF BETTER ATMOSPHERIC
MOISTURE WAS ORIENTED FROM THE HIGH PLAINS STRETCHING EAST THROUGH
THE UPPER MIDWEST THEN BENDING SOUTHEAST THROUGH THE GREAT LAKES
REGION THIS AFTERNOON. THIS APPEARS TO FIT WELL ALONG THE PROGGED
586-590 HEIGHT CONTOUR...WHICH APPEARS TO REMAIN NEARLY STATIONARY
THROUGH THE NEXT 24 HOURS. THIS AFTERNOON THE BOUNDARY WAS
POSITIONED ACROSS THE UPPER MIDWEST THROUGH THE UPPER PENINSULA OF
MICHIGAN...WHICH IS EXPECTED TO BE THE FOCAL POINT FOR CONVECTIVE
GENERATION LATER THIS AFTERNOON. CURRENT TIMING OF ARRIVAL INTO
NORTHERN IL CONTINUES TO BE JUST AFT 00Z...WITH THE PEAK BETWEEN
03-06Z. WITH THE VERY WARM SFC CONDITIONS THIS AFTN...POTENTIAL
ENERGY WILL LIKELY REMAIN ELEVATED UPON ARRIVAL OF
CLOUDS/CONVECTION...WHICH COULD FURTHER ENHANCE THUNDERSTORMS TO
POSSIBLY REACHING SEVERE LIMITS.
THE LOCATION OF GREATEST CONCERN WILL LIKELY BE ALONG AND NORTHEAST
OF A ROCKFORD TO KANKAKEE LINE...WITH THE MAIN HAZARDS FROM
THUNDERSTORMS BEING BRIEF HEAVY DOWNPOURS/WIND GUSTS TO 60MPH/HAIL
UP TO 1".
AS THE BOUNDARY SLIDES SOUTH ACROSS THE CWFA AFTER MIDNIGHT...WINDS
WILL TURN NORTH/NORTHEAST. LLVL MOISTURE APPEARS TO LINGER THRU
DAYBREAK WED. OVERNIGHT LOWS WILL REMAIN MILD ONE MORE NIGHT IN THE
LOW 70S...TO MID 70S CLOSER TO DOWNTOWN CHICAGO.
WEDNESDAY...
MID-LVL RIDGE CENTER WILL DRIFT SOUTHWEST...ALLOWING HEIGHTS TO
WEAKEN MARGINALLY OVER THE WESTERN GREAT LAKES REGION. GUIDANCE
CONTINUES TO PROG A WEAK WAVE SLIDING ACROSS THE NORTHERN CWFA WED
MORNING...WHICH ALONG WITH THE LINGERING LLVL MOISTURE COULD
TRANSLATE INTO POSSIBLE SHRA/TSRA WED MORNING FOR THE
CENTRAL/SOUTHERN CWFA. AT THIS TIME HAVE MAINTAINED A DRY FORECAST
FOR WED AS ANTI-CYCLONIC FLOW SHOULD SLOWLY SLIDE SOUTH ACROSS THE
LAKES AND STEADILY DRY THE SFC. NORTHEAST LLVL FLOW WILL CONTINUE TO
USHER IN DRIER AIR...WITH SLIGHTLY COOLER TEMPS ALONG THE LAKESHORE
COMMUNITIES. TEMPS FOR FAR NORTHEAST IL/NORTHWEST IN WILL HOVER IN
THE LOW/MID 80S...MEANWHILE FURTHER INLAND TEMPS WILL WARM INTO THE
UPR 80S TO POSSIBLY LOWER 90S ALONG AND SOUTH OF A LASALLE TO
KANKAKEE LINE.
CONFIDENCE...HIGH.
THURSDAY THROUGH LABOR DAY...
CONSIDERABLE CHANGES HAVE TAKEN PLACE IN THE FINAL PERIODS OF THE
EXTENDED...HOWEVER MODEL SPREAD DOES APPEAR TO HAVE DIMINISHED
MARGINALLY WITH RESPECT TO HIGH TEMPS FOR THE HOLIDAY WEEKEND.
ENSEMBLES CONTINUE TO DEMONSTRATE NOISE WITH A WIDE RANGE OF
SOLUTIONS BEYOND FRI. GUIDANCE DOES CONTINUE TO SHOW MID-LVL RIDGE
INFLUENCING THE WEATHER FOR THE WESTERN GREAT LAKES
THUR/FRI...HOWEVER WITH THE CWFA REMAINING ALONG THE NORTHEAST
PERIPHERY OF THE RIDGE...THE PROBABILITY OF ANY WAVES GENERATING
CLOUDS/CONVECTION IS INCREASED FOR THE AREA. CURRENT THINKING IS
THAT SFC RIDGE FROM WED WILL REMAIN IN PLACE THRU THUR THEN BEGIN TO
DRIFT SOUTHEAST THUR NIGHT. THIS WILL BRING THE NEXT CHC FOR
SHRA/TSRA TO THE CWFA THUR NIGHT INTO FRI...LINGERING THRU SAT
BEFORE BEGINNING TO DRY BACK OUT FOR SUN AND LABOR DAY.
ECMWF/GFS HAVE CONTINUED TO PROG A TROUGH DEVELOPING OVER THE
CANADIAN ROCKIES FRI AND PUSHING OVER THE GREAT LAKES REGION SUN.
WITH THE NOW EXPECTED TROUGHING EXPECTED ACROSS THE REGION FOR THE
SECOND HALF OF THE WEEKEND...TEMPS WILL LIKELY SWING IN THE COOLER
DIRECTION WITH HIGHS IN THE UPR 70S TO POSSIBLY MID 80S FOR LABOR
DAY.
CONFIDENCE...MEDIUM.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* WINDS BCMG NORTH EARLY THIS MORNING AND THEN NE SHORTLY THERE
AFTER.
* MVFR TO IFR CIGS ARE PSBL EARLY THIS MORNING.
* MVFR VSBY IS PSBL LATE TONIGHT INTO THURSDAY MORNING.
JEE
//DISCUSSION...UPDATED 06Z...
A BROAD AREA OF LOW PRESSURE STRETCHES FROM LAKE ONTARIO THROUGH
SOUTHERN WI WITH THE LOWS COLD FRONT FROM SAGINAW MI TO LA CROSSE
WI. THE FRONT WILL CONTINUE TO SINK SOUTH REACHING THE TERMINALS
EARLY THIS MORNING. WINDS WILL BECOME NORTH BEHIND THE FRONT AND
MVFR TO IFR CIGS MAY ACCOMPANY THE FRONTAL PASSAGE. LATEST
GUIDANCE SUGGESTS THE LOWER CIGS WILL NOT MAKE IT SOUTH OF THE
WI/IL STATE LINE AND TRENDS ON SATELLITE WOULD SUPPORT THIS TRAIN
OF THOUGHT. HOWEVER...DID NOT FEEL COMFORTABLE PULLING THE LOWER
CIGS JUST YET SO KEPT IN FEW TO SCT IFR/MVFR CIGS THIS MORNING.
ALSO THINKING VSBY WILL REMAIN VFR ABOVE 6SM THIS MORNING.
WINDS BECOME NE ARND 10 KT THIS MORNING WITH ANY LOWER CLOUD COVER
BURNING OFF BY MID AFTERNOON. ADDED IN THE POSSIBILITY OF MVFR
VSBY LATE TONIGHT AS GUIDANCE AND MODEL SOUNDINGS ARE ALL
SUGGESTING THE LOW LEVELS WILL BE RATHER SATURATED TONIGHT.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN WIND TRENDS...MEDIUM-HIGH CONFIDENCE IN TIMING.
* LOW CONFIDENCE IN MVFR/IFR CIGS. CIGS MAY REMAIN VFR THROUGH THE
PERIOD.
* MEDIUM CONFIDENCE IN REDUCED VSBY LATE TONIGHT.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
JEE
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THURSDAY...VFR.
FRIDAY...CHANCE TSRA...MAINLY FRIDAY EVENING.
SATURDAY...CHANCE TSRA.
SUNDAY...SLIGHT CHANCE TSRA.
MONDAY...VFR.
RC
&&
.MARINE...
242 PM CDT
A BROAD TROUGH STRETCHES ACROSS LAKE MICHIGAN THIS AFTERNOON WITH
GENERALLY SOUTHERLY WINDS ACROSS THE LAKE. AS THE TROUGH SAGS
SOUTHEAST OVER THE NEXT 24 HOURS...WINDS WILL TURN NORTHERLY AS HIGH
PRESSURE BUILDS OVER MINNESOTA AND WISCONSIN WITH WINDS PICKING BACK
UP INTO THE 15 TO 20 KT RANGE. WINDS THEN DIMINISH WEDNESDAY NIGHT
AND THURSDAY AS THE HIGH MOVES OVER LAKE MICHIGAN. ANOTHER FRONT
WILL PASS OVER LAKE MICHIGAN ON SUNDAY...WITH THE GRADIENT
TIGHTENING SUNDAY NIGHT AND MONDAY AS HIGH PRESSURE BUILDS OVER
ONTARIO. WINDS MAY INCREASE FOR A PERIOD INTO THE 30 KT RANGE
MONDAY...THEN DIMINISH MONDAY NIGHT INTO TUESDAY AS THE HIGH
BUILDS SOUTH OVER THE GREAT LAKES.
BMD
&&
.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:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
342 AM CDT WED AUG 28 2013
.SYNOPSIS...
ISSUED AT 341 AM CDT WED AUG 28 2013
MSAS SURFACE ANALYSIS AT 07Z INDICATED THE SURFACE COOL FRONT
REACHING WEST FROM LOW PRESSURE OVER SE LOWER MI ACROSS SOUTHERN
WI...FAR NORTHERN IA...TO A WEAK LOW NW OF VALENTINE NE. SURFACE
DEWPOINTS WERE POOLING IN THE LOWER 70S ALONG AND SOUTH OF THIS AXIS
TO THE HIGHWAY 20 CORRIDOR...WHILE FURTHER SOUTH...MID TO UPPER 60S
WERE COMMON ACROSS THE MUCH OF THE FORECAST AREA. FOG CHANNEL
SATELLITE IMAGERY INDICATED A LARGE FIELD OF POST FRONTAL STRATUS
AND FOG ADVECTING W-SW ACROSS WI...WHILE HINTS OF STRATUS WERE
STARTING TO SHOW UP AHEAD OF THE FRONT BETWEEN KOLZ AND KCGY IN NE
IA. OTHERWISE...IT WAS ANOTHER VERY WARM AND SOMEWHAT MUGGY NIGHT
ACROSS THE REGION WITH TEMPERATURES STILL IN THE MID TO UPPER 70S
AT 3 AM.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 341 AM CDT WED AUG 28 2013
MANY CHALLENGES IN THE FORECAST FOR TODAY AS THE TIMING OF FRONT AND
POSSIBLE CLOUDS WILL IMPACT TEMPERATURES...HUMIDITY AND THE HEAT
ADVISORY HEADLINES.
HAVE FOLLOWED A BLEND OF THE 00Z GFS AND ECMWF BRINGING THE FRONT
INTO FAR NW IL AND EAST CENTRAL IA BY LATE MORNING...THEN
STALLING TO ROUGHLY BISECT THE FORECAST AREA FROM NW TO SE BY
EVENING. ASSOCIATED LOW LEVEL MOISTURE CONVERGENCE WILL KEEP
SURFACE DEWPOINTS IN THE LOWER 70S FOR MUCH OF THE DAY ALONG AND
NE OF THE BOUNDARY WITH THERMAL MIXING IN THE LOW LEVEL NE FLOW
EXPECTED TO BE LIMITED TO AROUND 900 MB. ALONG AND SOUTHWEST OF
THE FRONT...ANOTHER DAY OF DEEP MIXING WITH SIMILAR 850 MB
TEMPERATURES AS YESTERDAY SHOULD YIELD SIMILAR HIGHS...WHILE
DEWPOINTS STAY A FEW DEGREES LOWER. BIG QUESTION WILL BE WHAT
HAPPENS WITH THE BACKDOOR POST FRONTAL STRATUS DECK CURRENTLY
RACING TOWARD THE AREA FROM WI...WHICH AT THE PRESENT RATE IS
SHOWN REACHING NW IL BY 7 AM. THE EARLIER RAP RUNS APPEARED TO
HAVE THE BEST HANDLE ON THIS MOIST AXIS AROUND 925 TO 900
MB...SHOWING IT REACHING INTO THE HIGHWAY 20 CORRIDOR EARLY THIS
MORNING...THEN WASHING OUT WITH DAYTIME HEATING AND WILL FOLLOW
THIS SCENARIO FOR NOW COUNTING ON MOSTLY SUNNY SKIES OVER THE
ENTIRE AREA MOST OF THE DAY.
WILL THUS HAVE HIGHS FROM THE MID 80S ACROSS THE NORTHEAST...90 TO
LOWER 90S ACROSS THE CENTRAL THIRD...THEN MID 90S IN THE SOUTH.
THIS MAY AGAIN THREATEN RECORD HIGHS FOR THIS DATE...ESPECIALLY AT
BRL...LISTED IN THE CLIMATE SECTION BELOW. WHEN COMBINED WITH
SURFACE DEWPOINTS LINGERING IN THE LOWER TO MID 70S WHERE THE
FRONT EVENTUALLY STALLS OUT...HEAT INDEX VALUES SHOULD EXCEED 100
BY AFTERNOON. WELL SOUTHWEST OF THE FRONT...DEWPOINTS WILL BE
LOWER...BUT AMBIENT TEMPERATURES INTO THE MID AND POSSIBLY UPPER
90S WILL RESULT IN WIDESPREAD 100 TO 103 HEAT INDEX VALUES IN THE
AFTERNOON. HAVE KEPT THE PREVIOUS HEAT ADVISORY GOING UNTIL 00Z AND
ADDED BUCHANAN AND JONES COUNTY IN EASTERN IA WHERE THE HEAT INDEX
NOW LOOKS LIKELY TO EXCEED 100.
WHILE SOME MODELS ARE ADVERTISING QPF ALONG AND NE OF THE BOUNDARY
TODAY AND TONIGHT...THIS LOOKS OVERDONE GIVEN THE CAPPING WARM
TEMPERATURES ALOFT. THIS CAP WEAKENS SOME TONIGHT...BUT WITH A
STRONG TRIGGER LACKING...WILL KEEP A DRY FORECAST. WITH THE FRONT
LINGERING OVER THE AREA...WARM AND SOMEWHAT HUMID AIR WILL REMAIN IN
PLACE OVER ESPECIALLY THE CENTRAL AND SOUTH. HAVE KEPT LOWS FROM THE
MID 60S NORTHEAST TO THE LOWER 70S ACROSS THE SOUTH.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 341 AM CDT WED AUG 28 2013
FORECAST FOCUS ON HOT AND HUMID AND MAINLY DRY THROUGH SATURDAY...
THEN MUCH COOLER BY LABOR DAY.
THURSDAY THROUGH SATURDAY NIGHT...RIDGING ALOFT AND A CAPPED
ATMOSPHERE TO REMAIN THROUGH MUCH OF THIS TIME FRAME. THERE IS A
SMALL CHANCE OF THUNDERSTORMS MAINLY FRIDAY NIGHT AS A RIDGE RIDER
TRACKS ACROSS THE MIDWEST. THE SURFACE BOUNDARY WILL LIFT BACK TO
THE NORTHEAST OF THE CWA BY FRIDAY. MAXIMUM TEMPERATURES ON THURSDAY
WILL BE IN THE UPPER 80S NORTHEAST TO THE MID 90S SOUTHWEST...AND IN
THE 90S OVER ALL THE CWA BOTH FRIDAY AND SATURDAY. THESE WILL BE
SCORCHERS WITH DEWPOINTS AT LEAST IN THE LOWER 70S. HIGHEST HEAT
INDEX VALUES LOOK TO BE 100 TO 105 IN OUR SOUTHERN COUNTIES ON
THURSDAY...AND OVER MUCH OF THE CWA FOR BOTH FRIDAY AND SATURDAY.
HEAT ADVISORY HEADLINES WILL MORE THAN LIKELY NEED TO BE ISSUED FOR
MUCH OF THIS PERIOD. IF BURLINGTON IOWA RECEIVES NO RAINFALL BY THE
END OF THIS MONTH THEY WILL GO INTO THE BOOKS WITH ONLY A TRACE OF
RAIN FOR THE ENTIRE MONTH OF AUGUST...AND THE DRIEST AUGUST ON
RECORD!
SUNDAY AND SUNDAY NIGHT...TIMING OF THE COLD FRONT WILL BE CRITICAL
AS FAR AS CHANCES FOR THUNDERSTORMS AND MAXIMUM TEMPERATURES. DID
NOTICE THE ECMWF HAS BACKED OFF ON THE REALLY CHILLY AIR FROM A
COUPLE OF RUNS AGO. NOW THE ECMWF BRINGS ONLY THE 8C 850 MB
TEMPERATURE AS FAR SOUTH AS NORTHERN IL INSTEAD OF THE 2C FROM
EARLIER RUNS. CURRENT GRID TEMPERATURES MAY BE TOO WARM ON SUNDAY
DEPENDING ON TIMING OF THE FRONT...AMOUNT OF CLOUD COVER AND ANY
RAINFALL. THERE DOES APPEAR TO BE AT LEAST A CHANCE FOR A FEW
THUNDERSTORMS TO FORM ALONG THE FRONT BUT IN A DRY SPELL YOU DON`T
WANT TO GET YOUR HOPES UP. BUT ONCE AGAIN THIS WILL DEPEND ON THE
TIMING OF THE FRONT AND AMOUNT OF INSTABILITY AND MOISTURE. WELL...
AT LEAST ON PAPER THERE IS ENOUGH FORCING FROM THE DIGGING TROUGH TO
HOPEFULLY TRIGGER AT LEAST SCATTERED STORMS.
NEXT WEEK...HIGH PRESSURE WILL BRING A PLEASANT LABOR DAY AND THE
EARLY PART OF THE SHORTENED WORK WEEK. SHOULD BE A REALLY NICE DAY
FOR GRILLING OUT IN THE BACKYARD. MAXIMUM TEMPERATURES SHOULD END UP
IN THE 70S NORTH AND 80S SOUTH ALONG WITH COMFORTABLE HUMIDITY.
NIGHTTIME LOWS WILL DROP INTO THE 50S TO LOWER 60S EARLY IN THE
WEEK. ACCORDING TO MY FAVORED ECMWF MODEL THERE WILL BE A BRIEF WARM
UP BY MID WEEK FOLLOWED SHORTLY THEREAFTER BY ANOTHER COLD FRONT.
HOWEVER...MUCH OF THE FIRST WEEK OF SEPTEMBER LOOKS ON THE DRY SIDE.
HAASE
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY EVENING)
ISSUED AT 1143 PM CDT TUE AUG 27 2013
6 KTS WEST TO SOUTHWEST WILL CONTINUE THROUGH LATE NIGHT...THEN AS
A WEAK FRONT APPROACHES FROM THE NORTH WEDNESDAY MORNING...WINDS
WILL BECOME VERY LIGHT FROM THE NORTHEAST TO EAST. CLEAR SKIES
OVERNIGHT WILL EVENTUALLY GIVE WAY TO SOME 3500 FT STRATOCUMULUS
NORTH...WHICH AT THIS POINT SHOULD BE SCATTERED AND VFR.
HOWEVER...THIS TREND WILL BE WATCHED FOR A POTENTIAL RISK FOR MVFR
STRATUS WEDNESDAY MORNING. IT REMAINS THE ONLY THREAT TO AVIATION
WEATHER...THOUGH LOW AT THIS TIME. ERVIN
&&
.CLIMATE...
ISSUED AT 341 AM CDT WED AUG 28 2013
RECORD HIGHS FOR AUGUST 28...
MOLINE.........96 IN 1953
CEDAR RAPIDS...96 IN 1955
DUBUQUE........97 IN 1984
BURLINGTON.....96 IN 1945
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR BENTON-BUCHANAN-
CEDAR-DES MOINES-HENRY IA-IOWA-JEFFERSON-JOHNSON-JONES-
KEOKUK-LEE-LINN-LOUISA-MUSCATINE-SCOTT-VAN BUREN-WASHINGTON.
IL...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR HANCOCK-HENDERSON-
HENRY IL-MCDONOUGH-MERCER-ROCK ISLAND-WARREN.
MO...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR CLARK-SCOTLAND.
&&
$$
SYNOPSIS...SHEETS
SHORT TERM...SHEETS
LONG TERM...12
AVIATION...ERVIN
CLIMATE...SHEETS
AREA FORECAST DISCUSSION
NWS JACKSON KY
308 AM EDT WED AUG 28 2013
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 307 AM EDT WED AUG 28 2013
A STRONG RIDGE CONTINUES TO DOMINATE FROM THE SOUTH CENTRAL US INTO
THE CENTRAL PLAINS. PRESENTLY...A SHORTWAVE ON THE PERIPHERALS OF THIS
RIDGE IS PUSHING SOUTHEAST ACROSS THE SOUTHERN GREAT LAKES. THIS WAVE
WILL BE THE FOCUS OF OUR WEATHER TODAY AS IT BRINGS A THREAT OF
SHOWERS AND A FEW THUNDERSTORMS BACK TO THE AREA. MODELS ALL HAVE
THIS SHORTWAVE PROGRESSING SOUTHEAST ACROSS THE EASTERN OHIO RIVER
VALLEY TODAY. HOWEVER...THERE ARE SOME DIFFERENCES ON EXACTLY HOW FAR
SOUTHWEST THIS SHORTWAVE WILL TRACK...AND ULTIMATELY...HOW FAR
SOUTHWEST THE HIGHER CHANCES FOR RAIN WILL REACH. 00Z NAM IS THE MOST
AGGRESSIVE BRINGING SCATTERED TO NUMEROUS SHOWERS ACROSS THE COAL
FIELDS TODAY. HOWEVER...LATEST HRRR DOESN`T SEEM TO SUPPORT THE NAM
EVEN TO A LITTLE DEGREE. MEANWHILE...THE ECMWF AND GFS BOTH SUGGEST
PRECIPITATION WILL BE CONFINED TO THE EASTERN MOST COUNTIES IN
KENTUCKY TODAY. GIVEN THE UNCERTAINTY...HARD TO GO VERY HIGH WITH THE
CHANCE OF RAIN TODAY...ESPECIALLY THE FARTHER WEST YOU GET. BEST
SHORTWAVE ENERGY PROBABLY WILL NOT ARRIVE UNTIL LATE IN THE DAY...SO
HAVE DELAYED POPS INTO THE EVENING HOURS...AND GONE WITH 20 PERCENT
CHANCES IN THE WEST TO 40 PERCENT IN THE FAR EAST. THERE IS A PRETTY
GOOD CHANCE THAT THESE POPS MAY BE TOO HIGH AS WE MAY HAVE A TOUGH
TIME GETTING DECENT COVERAGE. HIGHS TODAY WILL CLIMB INTO THE MID TO
UPPER 80S (AROUND 1 TO 2 DEGREES WARMER THAN YESTERDAY).
GOING TO MAINTAIN SOME SLIGHT POPS TONIGHT AS A WEAK BOUNDARY
ASSOCIATED WITH THE SHORTWAVE CONTINUES TO SAG SOUTHWARD. THIS
BOUNDARY SHOULD EXIT THE SOUTH ON THURSDAY...ALLOWING FOR A RAIN FREE
DAY. AN ISOLATED SHOWER COULD POP UP ALONG THE VIRGINIA OR TENNESSEE
BORDER BY LATE MORNING PRIOR TO THIS FRONT CLEARING THE AREA.
DESPITE THE BOUNDARY SAGGING SOUTH...TEMPERATURES WILL REMAIN JUST AS
WARM WITH HIGHS INTO THE MID TO UPPER 80S.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 307 AM EDT WED AUG 28 2013
THE UPPER LEVEL PATTERN DURING THE PERIOD WILL FEATURE A STRONG
UPPER LEVEL HIGH CENTERED NEAR THE TX/OK PANHANDLES...WITH TROUGHING
ON EITHER SIDE. THE AMPLITUDE OF THE PATTERN WILL FLUCTUATE AS UPPER
LOWS RIDE THROUGH THE WESTERLIES AROUND THE RIDGE. DEAMPLIFICATION
IS EXPECTED EARLY IN THE PERIOD...WITH REAMPLIFICATION TOWARD THE
END. THIS SET-UP PUTS OUR LOCAL AREA IN A GENERAL NW FLOW
ALOFT...FAVORING PERIODIC COLD FRONTAL PASSAGES. ONE FRONT WILL BE
EXITING TO OUR S AND SW AT THE START OF THE PERIOD. SLIGHTLY DRIER
AIR BEHIND THE FRONT SHOULD ALLOW FOR DRY WEATHER THROUGH FRIDAY
NIGHT.
THE FRONT WILL STALL AND WEAKEN AFTER IT PASSES...AND MORE HUMID AIR
WILL BE LOOMING JUST TO OUR S AND W. AS SURFACE HIGH PRESSURE
SLIPS AWAY TO OUR EAST...LOW LEVEL FLOW WILL SEND THIS AIR MASS BACK
INTO OUR AREA DURING THE WEEKEND. MODELS DO SHOW WEAK DISTURBANCES
ALOFT TRAVELING IN THE NW FLOW. COMBINED WITH INCREASING MOISTURE
AND WEAK ISENTROPIC LIFT...THIS MAY VERY WELL ALLOW SCATTERED
SHOWERS AND THUNDERSTORMS TO DEVELOP...AND 30-40 PERCENT POPS WILL
BE USED DURING THE WEEKEND.
AS THE NEXT UPPER LOW HEADS INTO THE GENERALIZED EAST CONUS
TROUGH...PATTERN AMPLIFICATION BEGINS BEFORE THE WEEKEND IS
FINISHED...AND THE REJUVENATED EAST CONUS TROUGH BRINGS ANOTHER COLD
FRONT SOUTHEAST TO OUR AREA. OUR BEST CHANCE AT PRECIP IS WITH
HEATING JUST AHEAD OF THE FRONT ON MONDAY. WILL STICK WITH HIGH
CHANCE POPS AT THIS POINT. THE BEST ESTIMATE FOR FROPA IS MONDAY
NIGHT AND POSSIBLY INTO EARLY TUESDAY. ANY PRECIP SHOULD END NW TO
SE AS DRIER AIR ARRIVES BEHIND THE FRONT. MODELS HAVE NOT BEEN
CONSISTENT CONCERNING THE DEGREE OF COOLING/DRYING BEHIND THIS
FRONT...AND A MODEL BLEND/AVERAGE WILL BE USED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 200 AM EDT WED AUG 28 2013
PATCHY VALLEY FOG IS EXPECTED AGAIN TONIGHT...LEADING TO SLIGHT
REDUCTIONS IN VISIBILITIES AT KLOZ AND KSME. OTHERWISE...VFR
CONDITIONS WILL CONTINUE THROUGH THIS EVENING. A WEATHER DISTURBANCE
WILL DROP SOUTH LATE IN THE DAY AND COULD GENERATE A FEW SHOWERS.
HOWEVER...CONFIDENCE IS LOW AS TO HOW FAR WEST THESE SHOWERS WILL
REACH...SO HAVE OPTED TO NOT INCLUDE IN THE TAFS AT THIS POINT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...KAS
LONG TERM...HAL
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
415 AM EDT WED AUG 28 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 428 PM EDT TUE AUG 27 2013
WV IMAGERY AND RUC ANALYSIS INDICATED WNW FLOW THROUGH THE NRN GREAT
LAKES ATOP A MID/UPPER LEVEL RIDGE CENTERED OVER MO/KS/AR. NO
SHORTWAVE TROUGHS WERE NOTED UPSTREAM THAT ARE LIKELY TO HAVE A
SIGNIFICANT AFFECT ON UPPER MICHIGAN. AT THE SFC...A WEAK
TROUGH/FRONT EXTENDED FROM NEAR MNM TO MSP WITH WEAK HIGH PRES TO
THE NW OF LAKE SUPERIOR BRINGING LIGHT NE LOW LEVEL FLOW ACROSS LAKE
SUPERIOR. PERSISTENT LOW CLOUDS OVER THE SRN HLF OF THE CWA...HAVE LIMITED
TEMPS AND RESULTANT INSTABILITY DESPITE DEWPOINTS REMAINING AROUND
70. THE LAKE BREEZE FRONT INTO NRN UPPER MI HAS PRODUCED MAINLY JUST
TCU WITH ONLY A FEW SPRINKLES. WHILE THE TSRA ALONG THE 900-700 MB
FGEN ZONE THROUGH S CNTRL UPPER MI HAD MOVED INTO NRN LAKE
MI...ADDITIONAL TSRA WERE DEVELOPING IN NE WI JUST TO THE NORTH OF
THE FRONT WHERE MLCAPE VALUES HAD CLIMBED INTO THE 2K-3K J/KG RANGE.
EXPECT MAINLY JUST ISOLD SHRA AND POSSIBLY A TSRA OVER CNTRL UPPER
MI ALONG THE LAKE BREEZE BOUNDARY LATE THIS AFTERNOON AND EVENING
WHERE INSTABILITY WAS MORE MODEST...ONLY TO NEAR 500-1000 J/KG. THE
STRONGER TSRA ALONG THE FRONT MAY JUST BRUSH THE FAR SRN CWA NEAR
MNM EARLY BUT SHOULD SAG SOUTH OF THE AREA BY 21Z-22Z. ADDITIONAL
ELEVATED SHRA/TSRA NEAR ESC LATE THIS AFTERNOON IN THE AREA OF
WAA/ISENTROPIC LIFT SHOULD ALSO MOVE OFF TO THE SE BY THIS EVENING.
LARGER SCALE SUBSIDENCE WILL THEN TAKE OVER TONIGHT AS WEAK TO
MODERATE 700-300 MB QVECTOR DIV AND SFC HIGH PRES BUILDS OVER THE
AREA. WITH THE LIGHT WINDS AND ABUNDANT LOW LEVEL MOISTURE...AREAS
OF FOG/STRATUS ARE EXPECTED TO DEVELOP. WITH ONLY WEAK DRY ADVECTION
AND DEWPOINTS ONLY DROPPING INTO THE LOWER TO MID 60S...MIN TEMPS
WILL REMAIN WELL ABOVE NORMAL. THE NNE LOW LEVEL FLOW TONIGHT INTO
EARLY WED COULD ALSO BRING FOG/STRATUS INTO LOCATIONS ALONG LAKE
SUPERIOR. AFTER DAYTIME HEATING BURNS OFF ANY LINGERING LOW
CLOUDS...SUNSHINE SHOULD PUSH INLAND TEMPS INTO THE LOWER TO MID 80S
WITH LOWER READINGS IN THE MID TO UPPER 70S ALONG LAKE SUPERIOR.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 414 AM EDT WED AUG 28 2013
HIGH PRESSURE WILL BE OVER NORTHERN LAKE MICHIGAN AT THE START OF
THE PERIOD AND LEAD TO CLEAR SKIES OVER THE AREA. THE CLEAR SKIES
AND LINGERING MOIST LOW LEVELS WILL LIKELY LEAD TO SOME LINGERING
PATCHY FOG DURING THE FIRST COUPLE OF HOURS IN THE MORNING. AFTER A
CLEAR START TO THE MORNING...CLOUDS AND PRECIPITATION CHANCES WILL
BE ON THE INCREASE HEADING INTO THE AFTERNOON. THIS IS DUE TO THE
NEXT SHORTWAVE ROUNDING THE UPPER RIDGE AXIS IN THE DAKOTAS. THERE
SHOULD BE AN MCS ASSOCIATED WITH THE INITIAL SHORTWAVE EXITING NORTH
DAKOTA THURSDAY MORNING ON THE NOSE OF THE LOW LEVEL JET AND WAA.
THIS COMPLEX WILL FOLLOW THE MEAN FLOW AND INSTABILITY AXIS TO THE
EAST-SOUTHEAST AND THROUGH NORTHWEST WISCONSIN AND MAINLY JUST
BRUSHING UPPER MICHIGAN LATE THUSDAY AFTERNOON THROUGH THURSDAY
NIGHT. THE SECONDARY SHORTWAVE WILL FOLLOW A SIMILAR TRACK ALTHOUGH
A TOUCH FARTHER SOUTH FOR LATE THURSDAY NIGHT INTO FRIDAY MORNING.
WILL CONTINUE THE HIGHEST POPS ALONG THE WISCONSIN BORDER AND KEEP
AT HIGH END CHANCES AND LOW END LIKELY VALUES AT THIS POINT. SINCE
THE NAM/GEM SLIDE THE SHORTWAVE FARTHER NORTH...WILL KEEP SOME
PRECIPITATION MENTION IN THE FORECAST FOR THE REST OF UPPER MICHIGAN
ON THURSDAY NIGHT INTO FRIDAY. BASED ON THE INSTABILITY/SHEAR
VALUES...THINK THE BEST CHANCES FOR SEVERE WEATHER WILL STAY
SOUTH OF THE AREA AND MAYBE BRUSH THE SOUTHERN TIER OF COUNTIES.
LABOR DAY WEEKEND IS STILL MARKED WITH SOME DIFFERENCES IN THE
TIMING/INSTENSITY OF THE STRONG SHORTWAVE TROUGH EJECTING OUT OF
THE PACIFIC NORTHWEST ON THURSDAY NIGHT. THIS SHORTWAVE WILL ROUND
THE UPPER RIDGE ON SATURDAY (WHICH IS TRANSITIONING WEST INTO THE
ROCKIES DURING THAT TIME) AND MOVE THROUGH THE UPPER GREAT LAKES
REGION SATURDAY NIGHT THROUGH MONDAY. A SURFACE LOW ASSOCIATED WITH
THE SHORTWAVE WILL MOVE EAST ACROSS ONTARIO DURING THAT TIME FRAME
AND DRAG A COLD FRONT ACROSS UPPER MICHIGAN (MOST LIKELY SATURDAY
NIGHT). WILL HIGHLIGHT THE BEST CHANCES FOR RAIN DURING THAT
SATURDAY NIGHT PERIOD...BUT INCLUDE SLIGHT CHANCES BEFORE/AFTER DUE
TO THE TIMING DIFFERENCES. THIS COLD FRONT WILL BRING MUCH COOLER
TEMPERATURES TO THE AREA FOR SUNDAY AND MONDAY. THERE MAY BE ENOUGH
WARM AIR AROUND ON SUNDAY TO KEEP HIGHS AROUND NORMAL...BUT MONDAY
LOOKS TO BE BELOW NORMAL AS 850MB TEMPS FALL TO AROUND 6C. HIGH
PRESSURE WILL BUILD OVER THE AREA FOR MONDAY INTO TUESDAY AND LEAD
TO DRY WEATHER...ALTHOUGH THERE MAY BE SOME UPSLOPE DRIZZLE EARLY ON
MONDAY IN THE FAVORED AREAS NEAR LAKE SUPERIOR. EXPECT CLOUDS TO BE
OVER THE AREA FOR MONDAY UNDER THE NORTH-NORTHWESTERLY FLOW BUT THEY
SHOULD PULL OUT MONDAY NIGHT. WITH THE UPPER RIDGE BUILDING BUILDING
BACK TO THE EAST...EXPECT TEMPERATURES TO BEGIN WARMING CLOSER TO
NORMAL FOR TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 133 AM EDT WED AUG 28 2013
WITH A WARM AND HUMID AIRMASS IN PLACE TONIGHT...EXPECT VLIFR
CONDITIONS AT ALL SITES WITH FOG CAUSED BY SOME UPSLOPE FLOW. MIXING
AND HEATING WILL DISSIPATE THE FOG EARLY WED MORNING AND CONDITIONS
AT ALL SITES WILL RAPIDLY GO BACK TO VFR THROUGH THE REST OF THE
FORECAST PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 428 PM EDT TUE AUG 27 2013
LIMITED PRESSURE GRADIENTS ACROSS LAKE SUPERIOR SHOULD KEEP WINDS
BELOW 20KTS THROUGH THE FORECAST PERIOD. AREAS OF FOG WILL PERSIST
ACROSS MUCH OF LAKE SUPERIOR WITH HIGH DEWPOINTS OVER THE REGION.
AS WINDS TURN TO THE NORTH TONIGHT...EXPECT THE FOG TO PUSH SOUTH
THROUGH WEDNESDAY MORNING AND THEN DIMINISH SOME AS SLIGHTLY DRIER
CANADIAN AIR MOVES SOUTH OVER THE LAKE THROUGH WEDNESDAY NIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
DENSE FOG ADVISORY UNTIL 11 AM EDT /10 AM CDT/ THIS MORNING FOR
LSZ240-245>249-265.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
134 AM EDT WED AUG 28 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 428 PM EDT TUE AUG 27 2013
WV IMAGERY AND RUC ANALYSIS INDICATED WNW FLOW THROUGH THE NRN GREAT
LAKES ATOP A MID/UPPER LEVEL RIDGE CENTERED OVER MO/KS/AR. NO
SHORTWAVE TROUGHS WERE NOTED UPSTREAM THAT ARE LIKELY TO HAVE A
SIGNIFICANT AFFECT ON UPPER MICHIGAN. AT THE SFC...A WEAK
TROUGH/FRONT EXTENDED FROM NEAR MNM TO MSP WITH WEAK HIGH PRES TO
THE NW OF LAKE SUPERIOR BRINGING LIGHT NE LOW LEVEL FLOW ACROSS LAKE
SUPERIOR. PERSISTENT LOW CLOUDS OVER THE SRN HLF OF THE CWA...HAVE LIMITED
TEMPS AND RESULTANT INSTABILITY DESPITE DEWPOINTS REMAINING AROUND
70. THE LAKE BREEZE FRONT INTO NRN UPPER MI HAS PRODUCED MAINLY JUST
TCU WITH ONLY A FEW SPRINKLES. WHILE THE TSRA ALONG THE 900-700 MB
FGEN ZONE THROUGH S CNTRL UPPER MI HAD MOVED INTO NRN LAKE
MI...ADDITIONAL TSRA WERE DEVELOPING IN NE WI JUST TO THE NORTH OF
THE FRONT WHERE MLCAPE VALUES HAD CLIMBED INTO THE 2K-3K J/KG RANGE.
EXPECT MAINLY JUST ISOLD SHRA AND POSSIBLY A TSRA OVER CNTRL UPPER
MI ALONG THE LAKE BREEZE BOUNDARY LATE THIS AFTERNOON AND EVENING
WHERE INSTABILITY WAS MORE MODEST...ONLY TO NEAR 500-1000 J/KG. THE
STRONGER TSRA ALONG THE FRONT MAY JUST BRUSH THE FAR SRN CWA NEAR
MNM EARLY BUT SHOULD SAG SOUTH OF THE AREA BY 21Z-22Z. ADDITIONAL
ELEVATED SHRA/TSRA NEAR ESC LATE THIS AFTERNOON IN THE AREA OF
WAA/ISENTROPIC LIFT SHOULD ALSO MOVE OFF TO THE SE BY THIS EVENING.
LARGER SCALE SUBSIDENCE WILL THEN TAKE OVER TONIGHT AS WEAK TO
MODERATE 700-300 MB QVECTOR DIV AND SFC HIGH PRES BUILDS OVER THE
AREA. WITH THE LIGHT WINDS AND ABUNDANT LOW LEVEL MOISTURE...AREAS
OF FOG/STRATUS ARE EXPECTED TO DEVELOP. WITH ONLY WEAK DRY ADVECTION
AND DEWPOINTS ONLY DROPPING INTO THE LOWER TO MID 60S...MIN TEMPS
WILL REMAIN WELL ABOVE NORMAL. THE NNE LOW LEVEL FLOW TONIGHT INTO
EARLY WED COULD ALSO BRING FOG/STRATUS INTO LOCATIONS ALONG LAKE
SUPERIOR. AFTER DAYTIME HEATING BURNS OFF ANY LINGERING LOW
CLOUDS...SUNSHINE SHOULD PUSH INLAND TEMPS INTO THE LOWER TO MID 80S
WITH LOWER READINGS IN THE MID TO UPPER 70S ALONG LAKE SUPERIOR.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 428 PM EDT TUE AUG 27 2013
SFC HIGH OVERHEAD WEDNESDAY NIGHT SLOWLY SINKING SE THROUGH
FRIDAY...AS A WEAK FRONTAL TROUGH LINGERS ACROSS CENTRAL AND S
ONTARIO. WEDNESDAY NIGHT INTO THURSDAY MORNING STILL LOOK DRY...OUT
AHEAD OF THE NEXT SHORTWAVE OVER S ONTARIO ROUNDING THE SIGNIFICANT
RIDGE DOMINATING MUCH OF THE CENTRAL U.S. IT STILL LOOKS LIKE THE
BEST CHANCE FOR CONVECTION AND MODERATE RAIN WILL BE ALONG AND S OF
THE WI BORDER THURSDAY NIGHT.
LARGE HIGH PRESSURE OVER CENTRAL CANADA WILL SHIFT ACROSS N
ONTARIO ON FRIDAY...LEAVING UPPER MI IN BETWEEN -2 TO -6C AIR OVER S
HUDSON BAY HOTTER 22-25C TEMPERATURES OVER THE CENTRAL PLAINS. WITH
A SERIES OF WEAKER DISTURBANCES SWINGING IN FROM THE NW IT WILL BE
DIFFICULT TO KEEP THE MENTION OF SHOWERS AND THUNDERSTORMS OUT OF
THE FCST FOR FRIDAY AND FRIDAY NIGHT...ALTHOUGH THE LATEST MODEL
GUIDANCE DOES SUGGEST THAT IT COULD BE TRIMMED BACK A BIT MORE THAN
MY LAST MINUTE 20Z UPDATE.
THE SFC LOW CENTERED OVER THE PLAINS WILL SINK TO OUR S ON SATURDAY.
THIS WILL RESTRICT MUCH OF THE HOTTER AIR FROM PUSH ACROSS THE UPPER
GREAT LAKES. THE MAIN STORY WILL BE THE DEEPENING SFC LOW OVER LAKE
WINNIPEG FRIDAY NIGHT/SATURDAY MORNING MOVING ACROSS CENTRAL AND S
ONTARIO SATURDAY NIGHT /BOTTOMING OUT PRESSURE WISE AROUND 997MB/.
THE COLD FRONT IS EXPECTED TO DRAG ACROSS W AND CENTRAL UPPER MI
OVERNIGHT...AND EXIT E UPPER MI SUNDAY MORNING.
THE 27/00Z ECMWF LOOKS TO BE QUICKER AND DEEPER STILL WITH THE
TIMING OF THE 500MB TROUGH SWINGING ACROSS S CENTRAL CANADA AND
SUPPRESSING THE DOMINANT RIDGE TO THE 4-CORNERS REGION...AND IS A
SIGNIFICANT OUTLIER COMPARED TO THE GFS ENSEMBLE MEMBERS. WITH THE
TROUGH FORMING A FULL-FLEDGED LOW OVER SE CANADA MONDAY/MONDAY
NIGHT...UPPER MI WILL BE ABLE TO GET SOME RELIEF FROM THE HEAT.
SINGLE DIGIT 850MB TEMPS WILL SLIDE IN SUNDAY NIGHT...WITH BOTH 12Z
RUNS OF THE ECMWF AND GFS SHOWING 4C MONDAY MORNING.
THE COOLER TEMPERATURES WILL BE SHORT LIVED AS THE HIGH AMPLITUDE
500MB RIDGE OVER THE SOUTHERN STATES EXTENDS ACROSS THE ROCKIES ON
MONDAY...AND PUSHES ACROSS THE N PLAINS/S CENTRAL CANADA AND EDGES
ACROSS THE UPPER GREAT LAKES ON TUESDAY. LOOK FOR 70S AND POSSIBLY
80S TO RETURN AGAIN BY THE MIDDLE OF NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 133 AM EDT WED AUG 28 2013
WITH A WARM AND HUMID AIRMASS IN PLACE TONIGHT...EXPECT VLIFR
CONDITIONS AT ALL SITES WITH FOG CAUSED BY SOME UPSLOPE FLOW. MIXING
AND HEATING WILL DISSIPATE THE FOG EARLY WED MORNING AND CONDITIONS
AT ALL SITES WILL RAPIDLY GO BACK TO VFR THROUGH THE REST OF THE
FORECAST PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 428 PM EDT TUE AUG 27 2013
LIMITED PRESSURE GRADIENTS ACROSS LAKE SUPERIOR SHOULD KEEP WINDS
BELOW 20KTS THROUGH THE FORECAST PERIOD. AREAS OF FOG WILL PERSIST
ACROSS MUCH OF LAKE SUPERIOR WITH HIGH DEWPOINTS OVER THE REGION.
AS WINDS TURN TO THE NORTH TONIGHT...EXPECT THE FOG TO PUSH SOUTH
THROUGH WEDNESDAY MORNING AND THEN DIMINISH SOME AS SLIGHTLY DRIER
CANADIAN AIR MOVES SOUTH OVER THE LAKE THROUGH WEDNESDAY NIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
DENSE FOG ADVISORY UNTIL 11 AM EDT /10 AM CDT/ THIS MORNING FOR
LSZ240-245>249-265.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1134 PM MDT TUE AUG 27 2013
.AVIATION...
06Z TAF CYCLE
VFR CONDITIONS WILL PREVAIL FOR THE OVERNIGHT PERIOD. ONE
EXCEPTION IS ALONG AND SE OF A LINE FROM KROW TO KCVS WHERE SOME
MVFR CIGS COULD DEVELOP BETWEEN 10 AND 14Z. CONFIDENCE IS LOW
ATTM...HOWEVER...DUE TO THE ABUNDANT HIGH CLOUDS ALREADY IN THIS
AREA. EXPECT A FEW STORMS TO DEVELOP AROUND 18Z WEDNESDAY ACROSS
THE HIGH TERRAIN...BEFORE SLOWLY MOVING NORTH THRU THE AFTN. NOT
EXPECTING MUCH MORE ACTIVITY THAN WHAT WAS OBSERVED TODAY...
ESPECIALLY ACROSS THE NORTH. MOISTURE WILL BEGIN TO CREEP
NORTHWARD FROM MEXICO...THUS THE SC AND SW MTNS COULD BE A BIT
MORE ACTIVE. LOCALLY HEAVY RAIN...BRIEF MVFR CIGS/VSBYS WILL BE
THE MAIN THREATS WITH THESE STORMS.
34
&&
.PREV DISCUSSION...915 PM MDT TUE AUG 27 2013...
UPDATED ZFP JUST SENT. TRIMMED POPS FOR REMAINDER OF TONIGHT.
CONVECTION CONTINUES TO WANE AND DESPITE THE INCREASE IN
PW...DEEP EASTERLY WINDS ALF ON EVENING RAOBS INDICATED A STABLE
AIRMASS. LATEST RUC13 INDICATES MINIMAL QPF AS WELL FOR THE
OVERNIGHT.
.PREV DISCUSSION...300 PM MDT TUE AUG 27 2013... HAVE
MADE SOME FAIRLY SUBSTANTIAL CHANGES TO THE MEDIUM AND EXTENDED
RANGE FORECAST IN FAVOR OF A MUCH WETTER PATTERN. THE LATEST CIRA
BLENDED TPW IMAGERY SHOWS A DEEP POOL OF 150 PCT OF NORMAL
MOISTURE ENTRENCHED OVER BAJA MEXICO AND NEARLY ALL OF TX.
MOISTURE TRANSPORT WILL BE IMPRESSIVE AS WE PROGRESS THRU THE END
OF THIS WEEK INTO THE LABOR DAY HOLIDAY AS A LARGE INVERTED TROUGH
SHIFTS NW OVER NM.
CURRENTLY THERE IS A RELATIVELY STABLE AND DRY AIRMASS IN PLACE OVER
CENTRAL AND EASTERN NM...LEADING TO ONLY ISOLATED STORM COVERAGE AT
BEST FOR FAR WESTERN NM. THERE WILL BE LITTLE CHANGE TO THIS THEME
THRU WEDNESDAY AS INDICATED BY THE BULK OF OPERATIONAL GUIDANCE...
INCLUDING HPC PROBABILISTIC QPF AND MODEL ENSEMBLES. AN UPTICK IN
COVERAGE IS HOWEVER EXPECTED WEDNESDAY FOR THE GILA REGION TO THE
SOUTH CENTRAL MTS.
THE AFOREMENTIONED MOISTURE SURGE ADVECTS QUICKLY NW ACROSS NM
STARTING THURSDAY. PWAT VALUES ARE PROGGED TO AVERAGE 1 TO 1.2
INCHES WHICH WILL APPROACH 150 PCT OF NORMAL. INSTABILITY IN ASSCN
WITH THE WELL DEFINED INVERTED TROUGH WILL RESULT IN AT LEAST SCT
COVERAGE FROM THE GILA REGION NORTH ACROSS THE CONT DVD INTO THE
NORTHERN MTS. STEERING FLOW WILL BE WEAKER WITHIN THE TROUGH AXIS
THUS LCL HEAVY RAIN IS POSSIBLE. THE GFS AND ECMWF BOTH INDICATE
MOIST INSTABILITY WITH THIS WAVE WILL BECOME TRAPPED UNDER AN
UPPER RIDGE SHIFTING BACK SOUTH OVER THE REGION FRIDAY. THIS WILL
WEAKEN STEERING FLOW FURTHER ELEVATING THE POTENTIAL FOR HEAVY RAIN.
VERY LITTLE CHANGE IS ADVERTISED BY THE GFS WITHIN A WELL DEFINED
STRONGLY UNSTABLE MOISTURE AXIS CENTERED OVER THE CONT DVD BOTH
SATURDAY AND SUNDAY. THE POTENTIAL FOR LCL HEAVY RAIN WILL BE THE
GREATEST FOR THIS PERIOD. THE 12Z ECMWF HAS TRENDED MUCH DRIER WITH
A SPRAWLING UPPER RIDGE OVER THE DESERT SW. SINCE THIS IS A BIG
CHANGE FROM PREVIOUS TRENDS HAVE PUSHED THAT ASIDE FOR NOW AND
RAISED POPS THRU THE HOLIDAY WEEKEND. A SPECIAL WX STATEMENT MAY BE
ON THE HORIZON WITH POTENTIAL FOR A FLASH FLOOD WATCH IF TRENDS
CONTINUE TO INDICATE HEAVY RAIN. THIS SHOULD SERVE TO RAISE PUBLIC
AWARENESS OF A RETURN TO A STRONGER MONSOON PATTERN AS A SIGNIFICANT
NUMBER OF OUTDOOR LABOR DAY ACTIVITIES WILL BE ONGOING.
THE GFS INTRODUCES ANOTHER WELL DEFINED MOIST EASTERLY WAVE FOR
MONDAY INTO THE MIDDLE OF NEXT WEEK WITH A FOCUS OVER NORTHERN/
WESTERN NM. THE HPC 8-14 DAY OUTLOOK INDICATES A GOOD CHANCE FOR
ABOVE NORMAL PRECIPITATION IN THIS AREA...SO WILL CONTINUE THE
TREND OF RAISING POPS.
GUYER
.FIRE WEATHER...
A STRONG UPPER LEVEL HIGH PRESSURE SYSTEM CENTERED OVER KANSAS CITY
THIS AFTERNOON WILL WEAKEN SOME AND GRADUALLY SHIFT ITS CENTER
WESTWARD OVER SOUTHERN CO BY THURSDAY. MEANWHILE AN EASTERLY WAVE
TRACKING SLOWLY NORTHWESTWARD ACROSS NORTHERN MEXICO WILL SPREAD
RICHER MOISTURE INTO SOUTHWEST PARTS OF THE FORECAST AREA WEDNESDAY.
A PORTION OF THIS WAVES ENERGY IS PROGGED TO LIFT NORTHWARD THROUGH
AZ THURSDAY AND FRIDAY. THIS SHOULD FUNNEL BETTER MONSOON MOISTURE
ACROSS MORE OF WESTERN NM AND TO A LESSER EXTENT CENTRAL PARTS OF
THE STATE WITH SCATTERED TO NUMEROUS THUNDERSTORMS MAINLY ALONG AND
WEST OF THE CENTRAL MOUNTAIN CHAIN BOTH DAYS. SUBSIDENCE CLOSER TO
THE CENTER OF THE HIGH PRESSURE SYSTEM SHOULD KEEP THE PLAINS ON THE
DRIER SIDE THROUGH THE END OF THE WORK WEEK WITH GRADUALLY WARMING
HIGH TEMPERATURES. THURSDAY AND FRIDAY...HIGHS ON THE PLAINS SHOULD
VARY FROM 6 TO 12 DEGREES ABOVE NORMAL WHILE WESTERN READINGS VARY
FROM NEAR NORMAL TO AROUND 3 DEGREES BELOW NORMAL.
OVER THE WEEKEND THE UPPER LEVEL HIGH PRESSURE SYSTEM WILL WEAKEN
SIGNIFICANTLY AND BROADEN OVER CO AND NM ALLOWING A RICH MONSOON
MOISTURE PLUME TO SPREAD UNDERNEATH THE RIDGE AND MORE SQUARELY OVER
NEW MEXICO. WITH PWAT VALUES AROUND 1 TO 1.5 INCHES ACROSS MUCH OF
WESTERN AND CENTRAL PARTS OF THE FORECAST AREA...THUNDERSTORMS WILL
BE CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL WITH A THREAT OF
FLASH FLOODING THURSDAY THROUGH SUNDAY. STORM MOTIONS WILL ALSO
SLOW TO A CRAWL AS THE WEAKENING DOME OF HIGH PRESSURE SPREADS OVER
THE REGION...ADDING TO THE FLASH FLOOD THREAT. THE PLAINS WILL ALSO
HAVE A CHANCE FOR WETTING PRECIP OVER THE WEEKEND...BUT HIGHER
PROBABILITIES SHOULD FAVOR CENTRAL AND WESTERN AREAS.
THE GFS AND ECMWF HAVE FAIR AGREEMENT THAT THE UPPER HIGH WILL
SLOWLY RESTRENGTHEN AND RECENTER NEAR KS/OK EARLY IN THE COMING WORK
WEEK. THIS WOULD ALLOW A LITTLE DRIER AIR TO FUNNEL INTO EASTERN
AREAS AND TIGHTEN THE FOCUS OF THE MONSOON MOISTURE PLUME MORE ALONG
THE CONTINENTAL DIVIDE. THIS WOULD ALSO ALLOW EASTERN HIGH
TEMPERATURES TO WARM...AFTER SOME POTENTIALLY COOLER READINGS
AREAWIDE OVER THE WEEKEND.
RELATIVE HUMIDITIES SHOULD REMAIN ABOVE CRITICAL THRESHOLDS
WEDNESDAY THROUGH MONDAY...WITH GOOD TO EXCELLENT OVERNIGHT
RECOVERIES. VENT RATES WILL GENERALLY BE GOOD OR BETTER...EXCEPT FOR
POCKETS OF POOR DISPERSION ASSOCIATED WITH PERIODS OF GREATER
THUNDERSTORM COVERAGE ACROSS CENTRAL AND WESTERN AREAS.
44
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1133 PM CDT TUE AUG 27 2013
.DISCUSSION...
Please see the below aviation discussion section.
&&
.AVIATION...
Look for VFR conditions to continue across West Central Texas for
the next 24 hours. Also, I`d plan you surface winds to be light,
mainly from the south around 10 knots or less.
Huber
&&
.PREV DISCUSSION... /ISSUED 629 PM CDT TUE AUG 27 2013/
DISCUSSION...
See aviation discussion below.
AVIATION...
VFR conditions will prevail the next 24 hours. With the tropical
moisture in place lowered clouds will move into the area early
morning, before sunrise. Model soundings suggest cigs should stay
above 3000 ft. NAM MOS, especially at Brady, is suggesting cigs
could go lower, but at this point I do not have the confidence to go
MVFR. After sunrise, cigs should begin to burn off by mid morning.
Winds will be light and mostly out of the south to southeast through
the TAF period.
PREV DISCUSSION... /ISSUED 340 PM CDT TUE AUG 27 2013/
SHORT TERM...(Tonight and Wednesday)
Isolated shower activity will be ending this evening, as an easterly
wave moves northwest. HRRR model seems to have been the better
model, indicating rapid weakening showers this afternoon. The NAM
and GFS models had more extensive coverage this afternoon over the
Big Country and Concho Valley. In any case...all models show
precipitation ending by early evening with loss of the suns heating.
Some patchy stratus possible late tonight and early Wednesday
morning...due to moist vegetation and light winds. Temperatures
rebound into the lower and mid 90s Wednesday with dry conditions and
and mostly sunny skies.
LONG TERM...(Thursday through Tuesday)
Dry and hot weather to prevail through the weekend.
The ECMWF and the GFS are still in good agreement, indicating that
once the wave moves out of the area tomorrow, the upper level high
pressure will settle back into the area. With the high dominating
the weather across the southern plains, looks like dry conditions
will prevail. The center of the high pressure will shift from the
mid Mississippi Valley on Wednesday, to Texas on Thursday, and into
the southern Rockies for the weekend. Since we don`t see the center
of the high sit directly over West Central Texas, temperatures are
more likely to be in the mid and upper 90s to near 100 rather than
something much warmer. But in any case, dry and warmer than normal
conditions will be the rule.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 71 95 71 97 72 / 10 5 5 5 5
San Angelo 70 93 70 96 71 / 10 5 5 5 5
Junction 70 93 70 95 70 / 10 5 5 5 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
Reimer/Huber
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
158 AM EDT WED AUG 28 2013
.SYNOPSIS...
A COLD FRONT WILL SLIDE FROM THE SOUTHERN GREAT LAKES THIS MORNING
SOUTH TO THE NORTH CAROLINA/VIRGINIA BORDER BY THURSDAY MORNING. WEAK
HIGH PRESSURE WILL ARRIVE BEHIND THIS COLD FRONT FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 115 AM EDT WEDNESDAY...
UPDATED FORECAST TO SLOW DOWN ONSET OF SHOWERS FROM UPSTREAM
SHOWERS OVER OHIO/WRN PA INTO THE GREAT LAKES. MID/HIGH CLOUDS ARE
IN AND OUT OVER THE AREA LEADING TO FOG AT TIMES IN THE CLEAR
BREAKS. OVERALL THINK FOG WILL BE PATCHY AND POSSIBLY DENSE AT
TIMES AS SKIES SHOULD BE CLOUDING UP AGAIN BY DAWN AS THE UPSTREAM
ACTIVITY NEARS. THE 12Z ECMWF APPEARS TO BE HANDLING THIS THE BEST
ATTM...ALONG WITH THE 03Z HRRR AND 00Z RAP. STILL LOOKS LIKE MAIN
FOCUS OF SHOWERS/STORMS BY MID MORNING INTO THE AFTERNOON WILL BE
ALONG AND EAST OF A LWB-ROA-MTV LINE.
PREVIOUS VALID DISCUSSION...
CONFIDENT ENOUGH THAT THE NORTHERN PART OF THE FORECAST AREA WILL
SEE RAINFALL WEDNESDAY MORNING TO GO WITH LIKELY RAIN CHANCES IN
THE FORECAST.
TIMING OF THE ARRIVAL OF THESE SHOWERS AND THUNDERSTORMS IS JUST
AS CRITICAL AS THE TRACK THE STORMS TAKE...AS INCREASED CLOUD
COVER DURING THE MORNING WILL HAVE A LIMITING AFFECT ON HEATING
AND INSTABILITY AS WE HEAD INTO THE AFTERNOON. AS SUCH...WHILE
RAIN WILL BE SCATTERED ACROSS THE AREA...STRONG THUNDERSTORM
ACTIVITY MAY REMAIN MORE ISOLATED. WILL KEEP AN EYE ON THIS
APPROACHING DISTURBANCE THROUGH THE NIGHT...AND ADJUST THE
FORECAST ACCORDINGLY.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY/...
AS OF 245 PM EDT TUESDAY...
WHAT PRECIPITATION WE HAVE AROUND WEDNESDAY EVENING WILL BE
DEPENDENT UPON HOW QUICKLY UPSTREAM CONVECTION TRAVERSES THE AREA
DURING THE DAY WEDNESDAY. OUR FORECAST WILL REFLECT ONE THAT HAS THE
WESTERN EXTENT OF ANY COMPLEX STILL ACROSS MAINLY THE NORTHERN AND
EASTERN PARTS OF THE AREA DURING THE EARLY EVENING. THE BULK OF THE
ACTIVITY WILL EXIT THE FORECAST AREA BY THE LATE EVENING. IN ITS
WAKE WILL BE LINGERING ISOLATED SHOWERS THROUGHOUT THE REMAINDER OF
THE NIGHT.
ON THURSDAY...WE WILL BE IN BETWEEN THE ROBUST NORTHWEST FLOW SYSTEM
AS OUR STEERING FLOW BECOMES MORE NORTHERLY TO NORTHEASTERLY. MODEL
GUIDANCE VARIES ON THE DEGREE OF COVERAGE OF SHOWERS AND
STORMS...BUT THE GENERAL TREND IS FOR A CONTINUATION OF ISOLATED TO
SCATTERED ACTIVITY AS COLD FRONT DRAWS CLOSER TO OUR NORTH.
ANY DAYTIME ACTIVITY SHOULD BEGIN TO WANE AROUND SUNSET WITH
ISOLATED SHOWERS POSSIBLE THROUGH ABOUT MIDNIGHT. THE CANADIAN AND
NAM SOLUTIONS ARE SUGGESTING LOW LEVEL FLOW BECOMES SOUTHEAST ACROSS
THE NORTHERN MOUNTAINS AND FOOTHILLS OF NORTH CAROLINA LATE THURSDAY
NIGHT. THIS WITH LINGERING MOISTURE IS ENOUGH TO ALLOW FOR SOME
ISOLATED SHOWERS IN THIS AREA BY DAYBREAK FRIDAY.
ON FRIDAY...LOW LEVEL FLOW BEGINS TO TREND MORE SOUTHERLY AS THE
SURFACE HIGH HEADS TOWARD THE EAST COAST. THIS HELPS BRING MOISTURE
BACK TO A GREATER EXTENT OF THE FORECAST AREA AND TOWARD THE FRONT
NORTH OF THE REGION. MODELS VARY ON THE LOCATION AND TIMING...BUT
THERE IS A HINT OF A WEAK SHORTWAVE TROUGH CROSSING THE AREA BY
FRIDAY AFTERNOON. THIS ALONG WITH DAYTIME HEATING WILL ALLOW FOR
ANOTHER DAY OF ISOLATED TO SCATTERED SHOWERS AND STORMS. AREAS ALONG
AND WEST OF THE CREST OF THE BLUE RIDGE WILL BE THE FOCUS FOR THE
BEST CONCENTRATION.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 115 PM EDT TUESDAY...
DIFFERENT MODEL GUIDANCE DURING THIS PORTION OF THE FORECAST PACKAGE
VARIES OF THE SPECIFICS...BUT IS FAIRLY CONSISTENT ON THE
GENERALITIES. GENERALLY SPEAKING...THE NORTHEAST U.S. IS EXPECTED TO
HAVE SOME DEGREE OF TROUGHINESS OVER IT DURING THIS PORTION OF THE
FORECAST...WITH NORTHWEST FLOW ALOFT OVER OUR REGION. CLOSER TO THE
SURFACE...HIGH PRESSURE WILL TAKE UP RESIDENCE ALONG THE EAST
COAST...AND PREVAILING FLOW AROUND IT WILL HELP DEVELOP FLOW FROM
THE SOUTH THAT WILL DIRECT MOISTURE INTO OUR REGION. DURING THE
MONDAY INTO TUESDAY TIME FRAME...A NORTHERN STREAM TROUGH WILL HELP
DEEPEN...AND THEN GRADUALLY EJECT THE EAST COAST TROUGH INTO THE
WESTERN ATLANTIC...AND UPPER LEVEL RIDGING WILL START NOSING INTO
THE AREA FROM THE MID-WEST.
THE ABOVE POINTS TOWARD THE FOLLOWING SCENARIO. MAINLY AFTERNOON AND
EARLY EVENING SCATTERED SHOWERS AND STORMS ARE EXPECTED SATURDAY AND
SUNDAY TRIGGERED PRIMARILY BE DAYTIME HEATING. HOWEVER...AND THIS IS
WHERE THE SPECIFICS GET TRICKY...UPSTREAM SHORTWAVE TROUGHS MAY RIDE
SOUTHEAST WITHIN THE NORTHWEST FLOW ALOFT AND ADD AN INCREASED
ELEMENT OF UPPER LEVEL DYNAMICS TO THE FORECAST PICTURE AND THUS
BETTER COVERAGE. SIMILARITY...THIS SAME FLOW MAY HELP ADVECT AN
UPSTREAM THUNDERSTORM COMPLEX INTO THE REGION...AND THIS TOO WOULD
ALLOW FOR BETTER COVERAGE OF SHOWERS AND STORMS...ESPECIALLY ACROSS
THE WESTERN PORTION OF THE AREA. PINPOINTING THESE FEATURES IS WHERE
MODEL GUIDANCE VARIES TOO GREATLY TO TRY TO INCORPORATE EITHER OF
THESE SCENARIOS INTO THE FORECAST AT THIS TIME.
MONDAY INTO TUESDAY...GUIDANCE ALSO VARIES AS TO THE TIMING AND
TRACK OF THE NORTHERN STREAM SYSTEM AND THUS THE IMPACT AND TIMING
OF ITS ASSOCIATED SURFACE COLD FRONT. WE WILL OFFER A SOLUTION
COMPARABLE TO WHAT IS PUT FORTH BY WPC WITH MONDAY AFTERNOON AND
EVENING LOOKING THE MOST PROMISING CURRENTLY. WOULD NOT BE SURPRISED
AS WE DRAW NEARER TO THIS TIME FRAME THAT THE FRONT ENDS UP ARRIVING
MONDAY NIGHT INTO TUESDAY MORNING...OR LATER.
TEMPERATURES THROUGH THIS TIME FRAME SHOULD SLOWLY INCREASE THROUGH
MONDAY AHEAD OF THE COLD FRONT...AND THEN BE COOLER AND LESS HUMID
ON TUESDAY WITH OUR CURRENT FORECAST TIMING OF THE COLD FRONT.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 145 AM EDT WEDNESDAY...
MID AND HIGH CLOUDS IN AND OUT OF TAF SITES WILL GIVE THE
VSBY FITS...AS SHOULD SEE SOME LOWERING VSBYS WITH ANY
CLEARING/THINNING OF HIGHER CLOUDS BUT SHOULD SEE OVERALL NO WORSE
THAN MVFR OVER MOST SITES DUE TO INCREASING HIGHER CLOUDS ARRIVING
BY 12Z FROM UPSTREAM CONVECTION. HOWEVER WILL THROW IN TEMPO
GROUPS ESPECIALLY DAN/BCB/BLF/LWB GIVEN THEY MAY HAVE LESS CLOUDS
OR ARE CLIMATOLOGICALLY FAVORED FOR LOWER VSBYS.
WILL SEE SHOWERS WORKING TOWARD LWB/ROA/LYH AROUND 12-15Z BUT
WEAKENING SOME. AS SHORTWAVE MOVES ACROSS NRN VA INTO THE
TIDEWATER THIS AFTERNOON WILL SEE INCREASING THREAT OF SHOWERS AND
SOME THUNDER ALTHOUGH INSTABILITY MAY BE ERASED SOME BY CLOUD
COVER...SO WILL TAKE TS OUT OF THE PREDOMINANT GROUP AND GO VCTS.
LOOKS LIKELY THAT ALONG AND EAST OF THE LWB-ROA-MTV LINE WILL SEE
BETTER THREAT OF SHOWERS. WILL KEEP TAFS VFR AFTER ANY FOG OR
LOWER CLOUDS MIX OUT BY MID MORNING...BUT DO NOT BE SURPRISED FOR
HEAVIER DOWNPOURS AROUND LYH THIS AFTERNOON TO NUDGE THEIR
VSBYS/CIGS TO UNDER VFR. A WEST TO NW WIND COMPONENT EXPECTED TO
BE PREVAILING AT 5-10 KNOTS AFTER 15Z THEN FALLING OFF AGAIN AFTER
00Z THU.
DURING THE EVENING THE SHOWERS/STORMS ARE EXPECTED TO TAKE A
DOWNWARD SHIFT WITH MODELS CONCENTRATING MORE ON A COMPLEX MOVING
FROM DCA-RIC-ORF. MAY SEE LINGERING SHOWERS IN LYH/DAN THOUGH.
SUBSIDENCE BEHIND THIS SYSTEM ALLOW SOME CLEARING TO START IN THE
WEST THIS EVENING THEN PERHAPS SPREAD EAST THU MORNING. THIS
COULD SET UP A SITUATION FOR DENSE FOG BUT LIMITING FACTOR MAY
STILL BE SOME DEBRIS CLOUDS AND SOME WIND.
SPOTTY SHOWERS AND THUNDERSTORMS WILL REMAIN IN THE FORECAST FOR
THURSDAY AS WEAK DISTURBANCES RIDE ACROSS THE AREA FROM THE GREAT
LAKES OVERTOP NORTHEASTERLY FLOW NEAR THE SURFACE AS HIGH
PRESSURE BUILDS IN. EXPECT A RETURN TO OVERALL VFR CONDITIONS UNDER
HIGH PRESSURE...WITH ONLY ISOLATED SHOWERS AT BEST FRIDAY AND
SATURDAY. OTHERWISE SOME PATCHY FOG LIKELY DURING THE OVERNIGHTS
INTO SATURDAY...WITH LATE NIGHT/EARLY MORNING MVFR/IFR CONDITIONS
POSSIBLE ESPECIALLY AT THE VALLEY LOCATIONS.
&&
.EQUIPMENT...
AS OF 100 PM EDT TUESDAY...
THE TEMPERATURE/DEWPOINT AT THE ROANOKE ASOS (ROA) WILL BE
AUGMENTED BY OBSERVERS FROM AN AUXILIARY UNIT UNTIL FURTHER
NOTICE. TIME OF RESTORATION OF THE PRIMARY EQUIPMENT WILL BE
WEDNESDAY AT THE EARLIEST.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS/NF/WP
NEAR TERM...AMS/NF/WP
SHORT TERM...DS
LONG TERM...DS
AVIATION...NF/WP
EQUIPMENT...AMS
FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE
.SHORT TERM...TODAY...TONIGHT...AND THURSDAY
ISSUED AT 405 AM CDT WED AUG 28 2013
FORECAST CONCERNS ON CLOUDS AND FOG THIS MORNING. MODELS FAIRLY
SIMILAR WITH FRONT SOUTH OF CWA. NORTHEAST WINDS AT SFC AND ALOFT BEHIND
FRONT...HAS LED TO WIDESPREAD LOW CLOUDS OFF LAKES TO MOVE OVER
MUCH OF CWA. LESS CLOUDS OVER NORTH CENTRAL HAS LED TO WIDESPREAD
DENSE FOG WITH VISIBILITIES FLUCTUATING AROUND 1/4 MILE. WILL
COVER WITH ADVISORY THROUGH 8AM. GUIDANCE SUGGESTS LOW CLOUDS TO
STICK AROUND A BIT THIS MORNING...WITH RUC SOUNDINGS CARRYING IT
INTO MID/LATE MORNING. HAVE LOWERED MAX TEMPS A BIT TODAY DUE TO
MORNING CLOUDS.
NUMBER OF MODELS CONTINUE TO CARRY LIGHT QPF FAR EASTERN WI TODAY.
NOT SEEING MUCH SUPPORT BESIDES SOME WEAK SURFACE CONVERGENCE...
THOUGH WITH CONTINUED MOIST AIR MASS AND ASSOCIATED INSTABILITY
CANNOT TOTALLY RULE OUT. WILL STAY DRY AT THIS TIME AND ADVISE
NEXT SHIFT.
FRONT BEGINS TO LIFT NORTH TONIGHT WITH BEST DYNAMICS OVER ND/MN.
EXPECT MCS A GOOD POSSIBILITY ON NOSE OF LLVL JET AS SUGGESTED BY MODELS.
GIVEN THERMAL PATTERN AND CORFIDI VECTORS...COMPLEX TO MOVE EAST
AND SOUTHEAST. MODELS SUGGEST COMPLEX MOVING INTO NORTHERN CWA BY
AFTERNOON. HAVE EXPANDED POPS GIVEN SCENARIO.
TEMPERATURES TO CONTINUE TO RUN WARMER THAN NORMAL THIS
PERIOD...THOUGH COOLER THAN PREVIOUS FEW DAYS.
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY
ISSUED AT 405 AM CDT WED AUG 28 2013
ALTHOUGH THERE ARE SOME TIMING DIFFERENCES AMONG THE
MODELS...PRECIPITATION CHANCES SHOULD BE HIGHEST ON THURSDAY
NIGHT AS AN UPPER LEVEL SHORT WAVE TOPS THE RIDGE. THERE WILL ALSO
BE ASSISTANCE FROM SOME 300MB DIVERGENCE AND AN APPROACHING
SURFACE SYSTEM.
THUNDERSTORM CHANCES REMAIN FOR FRIDAY AND SATURDAY WITH WARM AND
HUMID AIR IN PLACE...BUT DO NOT REALLY SEE MUCH FORCING. A COLD
FRONT PUSHING THROUGH TO START NEXT WEEK WILL BRING A CHANCE OF
SHOWERS AND THUNDERSTORMS THROUGH SUNDAY...AND COOLER
TEMPERATURES FOR MONDAY AND TUESDAY.
HAVE GENERALLY USED A MIX OF GUIDANCE AND PREVIOUS FORECAST
TEMPERATURES FOR MAX AND MIN TEMPERATURES DURING THE PERIOD.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1040 PM CDT TUE AUG 27 2013
NEARLY WEST TO EAST BAND OF SCATTERED SHOWERS AND
STORMS WILL LINGER INTO THE EARLY WEDNESDAY MORNING HOURS FOR
AREAS SOUTH OF A LINE FROM WISCONSIN RAPIDS TO OSHKOSH. ISOLATED
MVFR CIGS AND VSBYS EXPECTED WITH THE STORMS. OTHERWISE IFR CIGS
WILL CONTINUE TO SPREAD EAST OVER THE FORECAST AREA OVERNIGHT.
LIGHT WINDS COMBINED WITH LOW LEVEL MOISTURE AND RECENT RAINS TO
PRODUCE AREAS OF LIFR/IFR CIGS/VSBYS DUE TO FOG AND STRATUS. HIGH
PRESSURE BUILDING INTO THE AREA WEDNESDAY WILL DEVELOP VFR
CONDITIONS.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 8 AM CDT THIS MORNING FOR WIZ005-
010>012-018-019.
&&
$$
SHORT TERM.....TE
LONG TERM......MG
AVIATION.......TDH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
334 AM CDT WED AUG 28 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM CDT WED AUG 28 2013
..CURRENTLY AS OF 08Z..
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED DEEP TROUGHING
JUST OFF THE U.S. WEST COAST WHILE STRONG SUBTROPICAL RIDGING
CONTINUES TO DOMINATE THE CENTRAL PLAINS. A WEAK RIDGE AXIS EXTENDED
FROM THE SUBTROPICAL RIDGE NORTH INTO THE DAKOTAS. MONSOONAL
MOISTURE AND SHORTWAVES CONTINUE TO ROTATE AROUND THE SUBTROPICAL
RIDGE...FROM ARIZONA INTO THE DAKOTAS AND SOUTHEAST THROUGH THE
FORECAST AREA. REGARDING THE MOISTURE...RAP PRECIPITABLE WATER
ANALYSIS SHOWED VALUES OF 1.5-2 INCHES EXTENDING FROM THE DAKOTAS
SOUTHEASTWARD THROUGH MUCH OF THE FORECAST AREA. EARLY THIS MORNING
ALL MONSOONAL SHORTWAVES WERE EITHER TO THE EAST OR WEST OF THE
FORECAST AREA...RESULTING IN DRY CONDITIONS. AT THE SURFACE A WEAK
COLD FRONT WAS SLOWLY DROPPING SOUTH THROUGH THE FORECAST AREA...NOW
STRETCHED ACROSS NORTHERN IOWA AND FAR SOUTHERN WI. THE FRONT HAS
HAD A HARD TIME SCOURING OUT THE SURFACE MOISTURE WITH DEWPONTS
GENERALLY IN THE LOW 70S ACROSS THE AREA. THE COOLING WITH THE FRONT
HAS BEEN SHALLOW...EVIDENCED ON THE 00Z GRB SOUNDING WITH 925MB
TEMPS OF 22C COMPARED TO 29C AT DVN. SURFACE TEMPERATURES HAVE
FALLEN OFF INTO THE LOW TO MID 70S NORTH OF THE FRONT...AND MID TO
UPPER 70S TO THE SOUTH. THE COOLING INTERACTING WITH THE LINGERING
MOISTURE HAS CAUSED BOTH MIST AND LOW STRATUS TO FORM. VISIBILITIES
ARE LOWEST OVER NORTH CENTRAL WI DUE TO RECENT RAINS. 11-3.9 UM
IMAGERY SHOWED THE BULK OF THE STRATUS ACROSS CENTRAL AND EASTERN
WI.
..HAZARDS..
1. HEAT. NORTH OF I-90...HEAT INDICES ARE FORECAST BETWEEN
90-95...THEREFORE FEEL CONFIDENT NO ADDITIONAL HEAT ADVISORY IS
NEEDED. SOUTH OF I-90 HEAT INDICES ARE EXPECTED TO TOP OUT AROUND
95 TO AT MOST 100. GIVEN THAT THESE ARE BELOW ADVISORY CRITERIA
AND 5 TO 10 DEGREES LOWER THAN THE PAST FEW DAYS...HAVE DECLINED
TO ISSUE A HEAT ADVISORY HERE AS WELL.
2. DENSE FOG ACROSS TAYLOR AND CLARK COUNTIES...WHICH SHOULD
DISSIPATE BETWEEN 9-10 AM.
..SYNOPTIC OVERVIEW..
VERY LITTLE CHANGE IS FORECAST BY MODELS IN THE UPPER AIR PATTERN
DURING THE NEXT 24 HOURS. IF ANYTHING...THE WEAK RIDGE AXIS OVER THE
DAKOTAS GETS FLATTENED OUT AND PUSHED EAST...IN RESPONSE TO A
STRONGER MONSOONAL SHORTWAVE LIFTING INTO NORTH DAKOTA BY 12Z
THURSDAY. AT THE SURFACE...THE WEAK COLD FRONT OVER THE SOUTHERN
PORTION OF THE FORECAST AREA LOOKS TO CONTINUE TO SLOWLY DRIFT
SOUTH...PROGGED TO BISECT IOWA NORTHWEST TO SOUTHEAST BY 00Z. IN
ITS WAKE...HIGH PRESSURE BUILDS IN OVER WISCONSIN. THE FRONT MAY
START TO LIFT BACK TOWARDS THE AREA LATE TONIGHT IN RESPONSE TO WARM
ADVECTION AHEAD OF THE SHORTWAVE MOVING INTO NORTH DAKOTA.
..DETAILS..
SOLAR HEATING WILL HELP TO GRADUALLY IMPROVE VISIBILITIES AND MIX
OUT THE LOW STRATUS AIMING AT SOUTHWEST WI THIS MORNING. BY 18Z ALL
FOG AND STRATUS SHOULD BE GONE. OTHERWISE...DRY ADVECTION IN THE LOW
TO MID LEVELS OF THE ATMOSPHERE ACCOMPANYING THE SURFACE HIGH...
COMBINED WITH CAPPING BY A WARM LAYER AT 750MB...WILL HELP TO KEEP
CONDITIONS DRY TODAY. THE 28.00Z GFS DOES TRY TO CONVECT ACROSS
NORTHEAST IOWA NEAR THE FRONT THIS AFTERNOON...BUT IS THE ONLY MODEL
TO DO SO. HAVE KEPT THE FORECAST DRY DUE TO LIMITED CONVERGENCE ON
THE FRONT AND THE CAPPING POTENTIAL...ALONG WITH ALL OTHER MODELS
SUGGESTING DRY CONDITIONS ON THE FRONT. TEMPERATURES TODAY WILL BE
ABOUT 5 DEGREES COOLER WITH 925MB READINGS DOWN TO 24-26C VERSUS THE
28-30C THAT OCCURRED YESTERDAY. SURFACE DEWPOINTS...ON THE OTHER
HAND...ARE STILL GOING TO BE STUCK IN THE LOW TO PERHAPS MID 70S
SOUTH OF I-90. THUS HEAT INDICES IN THIS AREA OF 95 TO AT MOST 100
ARE EXPECTED. TO THE NORTH...DEWPOINTS SHOULD MIX/FALL INTO THE
60S...KEEPING HEAT INDICES MORE IN THE 90-95 RANGE.
FOR TONIGHT...GOOD MODEL AGREEMENT EXISTS ON THE WARM ADVECTION
SCENARIO. THE BIGGEST ISSUES ARE IF AND WHEN CONVECTION CAN FIRE
FROM THE WARM ADVECTION. HERE AGAIN...THE 28.00Z GFS IS QUICKEST AND
MOST EXPANSIVE...SUGGESTING CONVECTION WEST OF THE MS RIVER ALL
NIGHT. ALL OTHER GUIDANCE WAITS UNTIL AFTER MIDNIGHT...AND IN THE
CASE OF THE 28.00Z REGIONAL CANADIAN AS WELL AS THE 28.00Z NAM...
THEY NEVER FIRE ANY CONVECTION. FOR NOW HAVE LEANED MORE TOWARDS THE
CONSISTENT ECMWF AS IT ALSO HAS DONE BEST WITH CONVECTION AS OF
LATE. THE MODEL SUGGESTS ELEVATED CONVECTION FIRING AFTER MIDNIGHT
FROM GRAND FORKS DOWN TO AROUND AUSTIN. GIVEN THAT THIS CONVECTION
WILL OCCUR IN THE 1.5-2 INCH PRECIPITABLE WATER STREAM...LOCALLY
HEAVY RAIN COULD OCCUR WITH THE STORMS. ANOTHER MILD TO WARM NIGHT
EXPECTED AGAIN...WARMEST WEST OF THE MS RIVER WITH MORE CLOUDS AND
HIGHER DEWPOINTS.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 334 AM CDT WED AUG 28 2013
..HAZARDS..
1. HEAT. POTENTIAL FOR ANOTHER HEAT ADVISORY COME FRIDAY...
ESPECIALLY ACROSS NORTHEAST IOWA. SATURDAY ALSO HAS A POTENTIAL NEED
FOR A HEAT ADVISORY IF WARM AIR PROGGED THEN ADVECTS IN FASTER.
2. STORMS. THOSE STORMS THAT OCCUR THURSDAY NIGHT ALONG/NORTHEAST OF
I-94 COULD POSE A HEAVY RAIN CONCERN WITH A SMALL RISK OF DAMAGING
WINDS.
..SYNOPTIC OVERVIEW..
28.00Z MODEL GUIDANCE REMAINS IN GOOD AGREEMENT WITH YESTERDAYS
MODEL RUNS OF SHOWING THE SUBTROPICAL RIDGE RETROGRADING INTO THE
FOUR CORNERS REGION THIS WEEKEND. THIS RESULTS IN A GRADUAL FALL OF
500MB HEIGHTS OVER THE FORECAST AREA. ADDITIONALLY...THE BULK OF THE
DEEP TROUGH JUST OFF THE U.S. WEST COAST IS PROGGED TO EJECT OUT
ACROSS SOUTHERN CANADA THIS FRIDAY AND SATURDAY. MODELS HAVE
STRUGGLED A BIT ON THE DEGREE OF AMPLIFICATION WITH THIS TROUGH AS
IT APPROACHES NORTHERN ONTARIO AND LAKE SUPERIOR SUNDAY MORNING...
BUT THEY APPEAR NOW TO HAVE SETTLED DOWN. ALL INDICATIONS ARE THAT
AFTER IT PASSES LAKE SUPERIOR...THE TROUGH WILL THEN DIG INTO THE
EASTERN GREAT LAKES MONDAY AND TUESDAY...WHILE UPPER RIDGING BUILDS
BACK UP OVER THE NORTHERN PLAINS.
..DETAILS..
THE SHORTWAVE OVER NORTH DAKOTA AT 12Z THURSDAY LOOKS TO TRACK
ACROSS NORTHERN MN ON THURSDAY AND INTO UPPER MI THURSDAY NIGHT.
GIVEN THIS TRACK...THE BULK OF THE DYNAMIC FORCING WILL STAY NORTH
OF THE FORECAST AREA...THOUGH TAYLOR AND CLARK COUNTIES COULD GET
BRUSHED. MORE IMPORTANTLY ABOUT THIS SHORTWAVE IS THE ISENTROPIC
LIFT AND LOW LEVEL MOISTURE TRANSPORT OCCURRING WITH IT AND TO ITS
SOUTH. ON THURSDAY...THIS ISENTROPIC LIFT CENTERED ON THE 310-315K
SURFACES AND LOW LEVEL MOISTURE TRANSPORT SLOWLY MARCHES ACROSS THE
FORECAST AREA...GETTING HUNG UP ACROSS WISCONSIN AT 00Z FRIDAY. THE
STRONGEST LIFT/MOISTURE TRANSPORT IS SITUATED NORTH OF THE FORECAST
AREA...BUT STILL WARRANTS 20-40 PERCENT CHANCES. CHANCES INCREASE
ACROSS WISCONSIN THURSDAY NIGHT...ESPECIALLY ALONG/NORTHEAST OF
I-94...AS THE MOISTURE TRANSPORT INCREASES WITH THE NOCTURNAL
INCREASE OF THE LOW LEVEL JET. STRONG MODEL CONSENSUS FOR CONVECTION
THUS 60-70 PERCENT CHANCES SEEM REASONABLE. ALONG AND WEST OF THE MS
RIVER THURSDAY NIGHT...THERE MAY BE VERY LITTLE TO ANY ACTIVITY.
TEMPERATURES ON THURSDAY DEPEND ON HOW MUCH SUN WE SEE...AND WITH
925MB READINGS RANGING FROM 22C EAST TO 27C WEST...THERE COULD BE A
WIDE SPREAD IN HIGHS. FOLLOWED A GUIDANCE CONSENSUS FOR NOW
RESULTING HIGHS IN THE 80S...WARMEST WEST AND IN RIVER VALLEYS.
GUIDANCE CONSENSUS ALSO FOLLOWED FOR LOWS THURSDAY NIGHT.
FOR FRIDAY INTO FRIDAY NIGHT...MODELS CONTINUE TO SHOW A SECOND
SHORTWAVE DROPPING SOUTHEAST OUT OF CENTRAL MN THROUGH THE FORECAST
AREA ON FRIDAY. WITH THIS SHORTWAVE COMING THROUGH AT PEAK HEATING
AND PLENTY OF MOISTURE IN PLACE...NOTED BY PRECIPITABLE WATER VALUES
PROGGED BETWEEN 1.5-1.75 INCHES...NEED TO HAVE SOME CHANCES OF
SHOWERS AND THUNDERSTORMS. MODELS VARY A BIT ON THE STRENGTH OF THIS
SHORTWAVE THUS CHANCES ARE ONLY IN THE 20-30 RANGE. WE MIGHT BE ABLE
TO SQUEEZE IN FRIDAY NIGHT AS DRY PER 28.00Z ECMWF/NAM...HOWEVER...
THE 28.00Z GFS SHOWS WARM AIR ADVECTION RETURNING AHEAD OF A COLD
FRONT MARCHING ACROSS THE DAKOTAS. TO ACCOUNT FOR THE GFS
SCENARIO...HAVE KEPT 20-30 PERCENT CHANCES GOING. FRIDAY HIGHS ARE
ALSO TRICKY AS THEY DEPEND BOTH ON STRENGTH AND TIMING OF THE
SHORTWAVE. THE ECMWF/GFS/CANADIAN ALL SHOW AN INFLUX OF 28-30C 925MB
AIR INTO THE FORECAST AREA...WHICH COULD SUPPORT HIGHS IN THE MID
90S LIKE WE HAVE SEEN. BEST PROBABILITY OF THIS APPEARS TO BE IN
NORTHEAST IOWA WHICH THEN WOULD HAVE THE BEST CHANCE OF NEEDING A
HEAT ADVISORY. THE REST OF THE AREA IS A LITTLE MORE UNCERTAIN.
FOR SATURDAY AND BEYOND...
FOCUS IS ALL ON THAT TROUGH COMING ACROSS SOUTHERN CANADA. MODELS
ARE IN PRETTY GOOD AGREEMENT SHOWING THE COLD FRONT CROSSING THE
AREA DURING THE DAY SUNDAY. AHEAD OF THE FRONT...THERE WILL BE
ANOTHER SURGE OF WARM AIR COMING INTO THE AREA FOR SATURDAY. IF THE
GFS IS CORRECT WITH 925MB TEMPS OF 29-31C...A HEAT ADVISORY WOULD BE
REQUIRED...WHILE THE ECMWF IS MORE SCALED BACK WITH 925MB TEMPS OF
25-28C. FOR NOW THE HIGH TEMPERATURE FORECAST SPLITS THE DIFFERENCE
BETWEEN THESE MODELS. COULD SEE SOME WARM ADVECTION SHOWERS/STORMS
TOO...RIGHT THROUGH SATURDAY NIGHT. ADDITIONALLY...THERE COULD BE
SOME SHOWERS/STORMS THAT ARE FRONTOGENETICALLY DRIVEN AROUND THE
COLD FRONT ON SUNDAY. THEREFORE...20-40 PERCENT CHANCES PER
CONSENSUS ARE IN THE FORECAST. AFTER SUNDAY...DRY CONDITIONS WILL
PREVAIL AS HIGH PRESSURE BUILDS IN AND PERSISTS OVER THE AREA.
TEMPERATURES SUNDAY AND BEYOND ARE TRICKY AS THE 00Z AND 12Z ECMWF
RUNS ALTERNATE ON THE STRENGTH OF COLD ADVECTION. FOR NOW STUCK WITH
A MODEL CONSENSUS FOR HIGHS AND LOWS SUNDAY THROUGH TUESDAY...BUT IF
THE 00Z ECMWF RUNS ARE CORRECT...TEMPERATURES MAY NEED TO BE LOWERED
ANOTHER 5 DEGREES OR SO.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1147 PM CDT TUE AUG 27 2013
THE COLD FRONT HAS BECOME HARD TO DISCERN IN THE WIND FIELD BUT
APPEARS TO BE NEAR THE I90 CORRIDOR. THE WINDS HAVE COME AROUND TO
THE NORTHEAST AT KRST WHILE GOING CALM AT KLSE. EXPECT ENOUGH OF
SOUTHWARD DRIFT OVERNIGHT TO ALLOW A LIGHT NORTHEAST WIND TO
DEVELOP AT KLSE AS WELL. THE 28.03Z RAP CONTINUES TO SUGGEST THAT
SATURATION AT THE SURFACE WILL NOT OCCUR AT EITHER TAF SITE WHILE
THE 28.00Z NAM IS JUST AS INSISTENT THAT IT WILL. THIS CONTINUES
THE DILEMMA OF WHETHER FOG WILL FORM OR NOT OVERNIGHT. SOME FOG
DEVELOPING OVER NORTH CENTRAL WISCONSIN...BUT THIS AREA ALSO SAW
RAIN LAST NIGHT AND A LITTLE BIT AGAIN THIS EVENING WHILE NO RAIN
AS OCCURRED AT EITHER TAF SITE TO HELP PRIME THE LOW LEVELS FOR
FOG DEVELOPMENT. TEMP/DEW POINT SPREADS REMAIN IN THE 6 TO 8
DEGREE RANGE WITH NO SIGNS OF ANY VISIBILITY RESTRICTIONS YET.
BOTH MODELS STILL SHOW A BAND OF MOISTURE AROUND 925 MB DRIFTING
SOUTH OF THE TAF SITES OVERNIGHT AND WITH THE RAP SHOWING SOME
WEAK MOISTURE TRANSPORT OUT OF THE NORTHEAST INTO WESTERN
WISCONSIN...FEEL THAT A MVFR STRATUS DECK IS A MORE LIKELY OUTCOME
THAN FOG AT THIS POINT. HAVE THUS REMOVED THE IFR FOG FOR BOTH
TAFS WHILE KEEPING SOME MVFR VISIBILITY AND THE MVFR CEILING AT
KLSE. KRST STILL LOOKS TO BE ON THE WESTERN EXTENT OF ANY CLOUDS
THAT FORM OVERNIGHT AND WILL JUST SHOW A SCATTERED DECK THERE.
EVERYTHING SHOULD CLEAN OUT BY MID TO LATE MORNING WITH JUST SOME
SCATTERED CUMULUS THROUGH THE REST OF THE DAY.
&&
.CLIMATE...
ISSUED AT 334 AM CDT WED AUG 28 2013
THE FOLLOWING ARE RECORD HIGHS FOR LA CROSSE AND ROCHESTER
INTO LABOR DAY WEEKEND...GIVEN STILL MORE HEAT FORECAST. FOR MORE
CLIMATE INFORMATION...SEE OUR WEBSITE AND THE TOP NEWS STORY ON
THE RECENT HEAT.
LA CROSSE ROCHESTER
--------- ---------
WED 8/28 97/1955 96/1955
THU 8/29 95/1966 92/2012
FRI 8/30 97/2012 96/1941
SAT 8/31 95/1953 93/1960
SUN 9/1 98/1913 94/1937
MON 9/2 98/1937 94/1929
NORMAL HIGH TEMPERATURES THROUGH THIS PERIOD ARE 78-80 AT LA CROSSE
AND 76-78 AT ROCHESTER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR WIZ017-029.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...04
CLIMATE...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1147 PM CDT TUE AUG 27 2013
.UPDATE...
ISSUED AT 1147 PM CDT TUE AUG 27 2013
THE WEAK COLD FRONT CONTINUES TO MAKE SLOW SOUTHWARD PROGRESS AND
HAS REACHED THE I90 CORRIDOR. STILL SOME CONCERNS ON HOW FAR SOUTH
THE FRONT WILL MAKE IT OVERNIGHT...BUT WITH NOCTURNAL COOLING HEAT
INDICES HAVE FALLEN OUT OF THE WARNING/ADVISORY CATEGORIES. COULD
SEE THE NEED FOR ANOTHER HEADLINE ACROSS THE SOUTH FOR
WEDNESDAY...ESPECIALLY IF THE FRONT DOES NOT CLEAR THOSE AREAS
OVERNIGHT. GIVEN THE UNCERTAINTY OF WHAT THE FRONT WILL DO...WILL
ALLOW THE CURRENT HEAT HEADLINES TO EXPIRE AS SCHEDULED AT MIDNIGHT.
&&
.SHORT TERM...(TONIGHT THROUGH WEDNESDAY NIGHT)
ISSUED AT 325 PM CDT TUE AUG 27 2013
MAIN FORECAST CONCERNS THIS CYCLE...SHRA/TSRA CHANCES AND HEAT INTO
THIS EVENING...FOG POTENTIAL LATER TONIGHT/EARLY WED...TEMPERATURES
THRU THE PERIOD.
18Z DATA ANALYSIS HAD THE LOW/TROUGH/FRONT FROM NORTH OF KGRB TO
NEAR KEAU TO KFSD...MAKING SLOW PROGRESS SOUTH. NORTH OF THIS
FEATURE...LOWER STRATUS CLOUDS COMMON ACROSS NORTHERN WI INTO EAST
CENTRAL MN...WITH TEMPS IN THESE AREAS IN THE 70S TO MID 80S. SOUTH
OF THE TROUGH/FRONT...SKIES WERE AGAIN SUNNY/MOSTLY SUNNY WITH
DEW POINTS IN THE UPPER 60S TO LOWER 70S AND TEMPS QUICKLY WARMING
INTO THE UPPER 80S TO LOWER 90S. DRIER AIR IN THE 925-850MB LAYER
COMBINED WITH DEEPENING MIXING HAVING DOWNWARD PRESSURE ON THE
SFC DEW POINTS TODAY. EARLY AFTERNOON DEW POINTS NEAR TO AS MUCH AS
4F LOWER THAN AT 18Z MON. EARLY AFTERNOON HEAT INDICES IN THIS
AIRMASS WERE IN THE UPPER 80S/90S...STILL MAKING FOR ANOTHER DAY OF
MUGGY/UNCOMFORTABLE CONDITIONS.
27.12Z MODELS INITIALIZED WELL...EXCEPT GFS WHICH LOOKS DISPLACED
WITH ITS SFC DEW POINT ANALYSIS ACROSS THE UPPER MIDWEST. SOLUTIONS
QUITE SIMILAR FOR TONIGHT THRU WED NIGHT...BUT FOR GFS MORE ROBUST
THAN THE OTHERS WITH PW VALUES AND SHRA/TSRA DEVELOPMENT ALONG THE
RETURNING /WARM/ FRONT LATE WED NIGHT. DPROG/DT OF 500MB HGTS AT
27.12Z SHOWED THE MODEL RUNS OF 25.12Z AND 26.12Z VERIFIED VERY WELL
ACROSS NOAM/EASTERN PAC AS FLOW IS DOMINATED BY A LARGE UPPER RIDGE
CENTERED OVER KS/MO. MODELS SHOW A TIGHTENING CONSENSUS TONIGHT/WED
AS THE LARGE BLOCKY RIDGE MOVES LITTLE AND HGTS RISE A BIT OVER THE
DAKOTAS INTO SOUTH-CENTRAL CAN. IMPROVING SIGNAL/CONSENSUS FOR AN
EAST-SOUTHEAST MOVING SHORTWAVE TO BE NEAR THE MAN/ND BORDER BY 12Z
THU. CHECK OF OBS VS. MODEL DATA AT 18Z SHOWED ALL TO BE REASONABLE
WITH THE SFC MASS FIELDS OVER THE CENTRAL CONUS. MOST WERE A BIT
HIGH WITH SFC DEW POINTS OVER THE FCST AREA...AGAIN DUE TO SOME DRIER
925-850MB AIR AND INCREASING MIXING. MODELS DOING A DECENT JOB WITH
THE LOWER STRATUS/925MB MOISTURE NORTH OF THE TROUGH/FRONT AXIS.
MOST IF NOT ALL MODELS TOO FAR WEST/SOUTH WITH 12-18Z PRECIP ACROSS
WI. PER WV IMAGERY MODELS APPEAR REASONABLE WITH THE SHORTWAVE
DETAILS OVER NOAM/EASTERN PAC. NO ONE MODEL FAVORITE AND WITH THE
TIGHTENING CONSENSUS...SIDED WITH A MODEL/ENSEMBLE BLEND. SHORT TERM
FCST CONFIDENCE GOOD THIS CYCLE.
IN THE SHORT TERM...LITTLE IN THE WAY OF MOISTURE TRANSPORT/THETA-E
CONVERGENCE WITH THE TROUGH/FRONT TO SLIDE ACROSS THE AREA THROUGH
THIS EVENING...WITH INDICATIONS OF 850-700MB MOISTURE DIVERGENCE.
DEW POINTS MORE IN THE UPPER 60S/LOW 70S NOT HELPING MATTERS AS FAR
AS INSTABILITY AND ERODING THE CAPPING IN THE 850-700MB LAYER.
CLOSEST TO ERODING THE CAP OVER THE EAST END OF THE FCST AREA AND
WILL LEAVE A SMALL SHRA/TSRA CHANCE THERE INTO EARLY THIS EVENING.
TROUGH SLIPS THRU THIS EVENING WITH A WEAK BUBBLE OF CAN HIGH
PRESSURE BUILDING IN FOR WED. HIGH PROVIDES SOME WEAK LOW LEVEL
COLD ADVECTION AND NORTHEAST SFC-850MB FLOW. 925MB TEMPS IN THE 24C
TO 27C RANGE WED VS. AROUND 30C THE PAST 2-3 DAYS. OF BIGGER CONCERN
IS THE 925MB MOISTURE/STRATUS NORTH OF THE FRONT/TROUGH...WITH GOOD
MODEL SIGNAL FOR THIS MOISTURE/CLOUDS TO ADVECT SOUTHEAST INTO
ACROSS THE AREA LATER TONIGHT THEN LINGER WELL INTO WED. THIS
MOISTURE ALONG WITH COOLING SFC-850MB TEMPS AND THE HIGH DEW
POINTS FAVORABLE FOR FOG IN LOCATIONS THAT DO NOT BECOME COVERED
WITH STRATUS. THESE WOULD HAVE MAJOR IMPACTS ON HIGHS WED...AS IT
IS IN NORTHERN WI TODAY. DUE TO THIS CONCERN...AND HEAT INDICES
STRUGGLING TO REACH HEADLINE CRITERIA...WILL LET HEAT ADVISORY/
WARNING EXPIRE THIS EVENING. SMALL CHANCE A HEAT HEADLINE MAY BE
NEEDED ACROSS THE SOUTH END OF THE FCST AREA WED AFTERNOON...BUT MID
CREW WILL HAVE TO EVALUATE THE CLOUDS/FOG LATER TONIGHT AND MORE
DETAILED IMPACT ON TEMPS WED.
TROUGH/FRONT STARTS TO RETURN NORTHEAST AS A WARM FRONT WED NIGHT.
GFS ABOUT THE ONLY MODEL GENERATING ANY SHRA/TSRA WITH THIS FEATURE
IN/NEAR THE FCST AREA THRU 12Z THU. GFS HAS PW VALUES IN THE 1.5 TO 2
INCH RANGE OVER THE WEST HALF OF THE FCST AREA LATER WED NIGHT...
RESULTING IN 500-1500 J/KG MU CAPE...WHILE BULK OF OTHER MODELS MORE
IN THE 1.5 INCH RANGE AND MU CAPE AROUND 500 J/KG. HOWEVER...LOWER
LEVEL THERMO-DYNAMIC FORCING WEAK IN ALL MODELS. ONLY CARRIED A SMALL
SHRA/TSRA CHANCE OVER THE NORTHWEST CORNER OF THE FCST AREA LATE WED
NIGHT...WHICH BLENDS WITH NEIGHBORING GRIDS FOR NOW. USED A BLEND OF
GUIDANCE LOWS TONIGHT/WED NIGHT. WITH POTENTIAL FOR STRATUS AND
IMPACTS ON HIGHS WED...TRENDED A BIT TOWARD COOLER OF GUIDANCE HIGHS.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 325 PM CDT TUE AUG 27 2013
MAIN FORECAST CONCERNS FOR THE THURSDAY THRU FRI NIGHT PERIOD...
SHRA/TSRA CHANCES WITH THE RETURNING FRONT THU/THU NIGHT THEN NEXT
APPROACHING TROUGH FRI/FRI NIGHT. TEMPERATURES THRU THE PERIOD.
MODELS REMAIN IN REASONABLY GOOD AGREEMENT THU/THU NIGHT AS THE
ND/MAN SHORTWAVE PASSES...THE MID LEVEL RIDGE AXIS IS PUSHED WEST
AND HGTS OVER THE REGION BEGIN TO FALL. NEXT STRONGER SHORTWAVE
HEADED ACROSS SOUTHERN CAN PUSHES THE RIDGE AXIS BACK EAST...INTO
THE UPPER MIDWEST FOR FRI/FRI NIGHT. FCST CONFIDENCE IN THE THU
THRU FRI NIGHT PERIOD IS AVERAGE TO GOOD.
WARM FRONT AND SFC-850MB MOISTURE/CAPE AXIS MOVE EAST/NORTHEAST
ACROSS THE FCST AREA THU/THU NIGHT. HOWEVER THE ND/MAN SHORTWAVE
PROGGED TO PASS NORTH/EAST OF THE FCST AREA WITH LOWER LEVEL THERMO-
DYNAMIC FORCING REMAINING ON THE WEAK SIDE AT LEAST THRU THU INTO
THU EVENING. MODEL SOUNDINGS SHOWING SOME CAPPING IN THE 900-800MB
LAYER AS WELL ON THU. WITH THE FRONT MOVING THRU THE AREA...DID
CONTINUE SOME 20-30 PERCENT SHRA/TSRA CHANCES THU. 925-850MB LOW
LEVEL JET INCREASES THU NIGHT...WITH AN INCREASE OF MOISTURE
TRANSPORT/THETA-E CONVERGENCE INTO THE AREA...ESPECIALLY EAST OF
THE MS RIVER. WITH THE IMPROVING MODEL CONSENSUS...RAISED SHRA/TSRA
CHANCES THU NIGHT...MAINLY NORTHEAST OF I-94. YET ANOTHER SHORTWAVE
DROPS SOUTHEAST INTO/ACROSS THE REGION IN THE NOW NORTHWEST FLOW
ALOFT FRI/FRI NIGHT. THIS DRAGS A BROAD/WEAK SFC LOW AND A 925-700MB
TROUGH EAST/SOUTHEAST ACROSS THE AREA. 20-30 PERCENT SHRA/TSRA
CHANCES FOR MUCH OF THE AREA FRI/FRI NIGHT LOOK REASONABLE AT THIS
TIME. WARM BUBBLE OF AIR PUSHES BACK INTO THE AREA FOR FRI WITH SFC
DEW POINTS IN THE UPPER 60S/LOW 70S. IF DRY WEATHER PREVAILS FRI VS.
THE POTENTIAL OF SCT SHRA/TSRA AND MORE CLOUDS...925MB TEMPS WOULD
SUPPORT HIGHS IN THE LOW-MID 90S WHICH WOULD SEND HEAT INDICES BACK
INTO THE 95-105 RANGE. MAY NEED ANOTHER HEAT ADVISORY CENTERED ON
FRI AFTERNOON. WITH SOME DETAIL UNCERTAINTIES...FAVORED THE MODEL/
ENSEMBLE CONSENSUS OF THU THRU FRI NIGHT HIGHS/LOWS FOR NOW.
FOR SATURDAY THRU TUESDAY /DAYS 4-7/...
MEDIUM RANGE MODEL RUNS OF 27.00Z/27.12Z IN REASONABLE AGREEMENT
SAT/SUN FOR A STRONGER SHORTWAVE TO BE TOPPING THE CENTRAL/WESTERN
NOAM RIDGING SAT THEN DROPPING ACROSS THE WESTERN GREAT LAKES SUN.
SOME STRENGTH/TIMING DIFFERENCES AT DAY 4/5 BUT THIS TO BE EXPECTED.
OVERALL TREND IS STRONGER WITH THIS FEATURE. REASONABLE AGREEMENT
FOR THE PATTERN TO SLOWLY PROGRESS MON/TUE WITH THE MID LEVEL RIDGING
BUILDING BACK EAST TOWARD/INTO THE UPPER MIDWEST BY TUE. ECMWF WITH
THE BETTER OVERALL RUN-TO-RUN CONSISTENCY THRU THE PERIOD. FCST
CONFIDENCE IN THE DAY 4-7 PERIOD IS AVERAGE THIS CYCLE.
DUE TO DIFFERENCES IN TIMING...MODELS PUSH A MDT COLD FRONT SOUTHEAST
ACROSS THE REGION SOMETIME SAT OR SUN. 27.12Z MODEL CONSENSUS BRINGS
THE FRONT THRU LATE SAT/SAT NIGHT...WITH A SECONDARY TROUGH/FRONTAL
PASSAGE SUNDAY. SMALL SHRA/TSRA CHANCES SAT/SUN PER THE MODEL
CONSENSUS REASONABLE AT THIS TIME UNTIL MOISTURE/FRONTAL DETAILS
BECOME CLEARER. BETTER CONSENSUS FOR A MDT TO STRONG...COOLER
CANADIAN HIGH TO SETTLE ACROSS THE WESTERN GREAT LAKES REGION FOR
MON/TUE AS RIDGING ALOFT BUILDS INTO MAN/SASKAT AND TROUGHING DIGS
INTO THE EASTERN GREAT LAKES. LABOR DAY AND TUE POISED TO BE A COUPLE
OF COOLER/MORE COMFORTABLE AND DRY DAYS. OWING TO TIMING DIFFERENCES
STAYED WITH THE MODEL/ENSEMBLE CONSENSUS FOR HIGHS/LOWS FOR SAT THRU
TUE. TREND FOR MON/TUE TEMPS IS NOW NEAR TO A BIT BELOW NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1147 PM CDT TUE AUG 27 2013
THE COLD FRONT HAS BECOME HARD TO DISCERN IN THE WIND FIELD BUT
APPEARS TO BE NEAR THE I90 CORRIDOR. THE WINDS HAVE COME AROUND TO
THE NORTHEAST AT KRST WHILE GOING CALM AT KLSE. EXPECT ENOUGH OF
SOUTHWARD DRIFT OVERNIGHT TO ALLOW A LIGHT NORTHEAST WIND TO
DEVELOP AT KLSE AS WELL. THE 28.03Z RAP CONTINUES TO SUGGEST THAT
SATURATION AT THE SURFACE WILL NOT OCCUR AT EITHER TAF SITE WHILE
THE 28.00Z NAM IS JUST AS INSISTENT THAT IT WILL. THIS CONTINUES
THE DILEMMA OF WHETHER FOG WILL FORM OR NOT OVERNIGHT. SOME FOG
DEVELOPING OVER NORTH CENTRAL WISCONSIN...BUT THIS AREA ALSO SAW
RAIN LAST NIGHT AND A LITTLE BIT AGAIN THIS EVENING WHILE NO RAIN
AS OCCURRED AT EITHER TAF SITE TO HELP PRIME THE LOW LEVELS FOR
FOG DEVELOPMENT. TEMP/DEW POINT SPREADS REMAIN IN THE 6 TO 8
DEGREE RANGE WITH NO SIGNS OF ANY VISIBILITY RESTRICTIONS YET.
BOTH MODELS STILL SHOW A BAND OF MOISTURE AROUND 925 MB DRIFTING
SOUTH OF THE TAF SITES OVERNIGHT AND WITH THE RAP SHOWING SOME
WEAK MOISTURE TRANSPORT OUT OF THE NORTHEAST INTO WESTERN
WISCONSIN...FEEL THAT A MVFR STRATUS DECK IS A MORE LIKELY OUTCOME
THAN FOG AT THIS POINT. HAVE THUS REMOVED THE IFR FOG FOR BOTH
TAFS WHILE KEEPING SOME MVFR VISIBILITY AND THE MVFR CEILING AT
KLSE. KRST STILL LOOKS TO BE ON THE WESTERN EXTENT OF ANY CLOUDS
THAT FORM OVERNIGHT AND WILL JUST SHOW A SCATTERED DECK THERE.
EVERYTHING SHOULD CLEAN OUT BY MID TO LATE MORNING WITH JUST SOME
SCATTERED CUMULUS THROUGH THE REST OF THE DAY.
&&
.CLIMATE...
ISSUED AT 334 PM CDT MON AUG 26 2013
THE FOLLOWING ARE RECORD HIGHS FOR LA CROSSE AND ROCHESTER
THROUGH LABOR DAY WEEKEND...GIVEN THE HEAT FORECAST. FOR MORE
CLIMATE INFORMATION...SEE OUR WEBSITE AND THE TOP NEWS STORY ON
THE HEAT.
LA CROSSE ROCHESTER
--------- ---------
WED 8/28 97/1955 96/1955
THU 8/29 95/1966 92/2012
FRI 8/30 97/2012 96/1941
SAT 8/31 95/1953 93/1960
SUN 9/1 98/1913 94/1937
MON 9/2 98/1937 94/1929
NORMAL HIGH TEMPERATURES THROUGH THIS PERIOD ARE 78-80 AT LA CROSSE
AND 76-78 AT ROCHESTER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...04
SHORT TERM...RRS
LONG TERM....RRS
AVIATION...04
CLIMATE......WETENKAMP
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
620 AM EDT WED AUG 28 2013
.SYNOPSIS...
WEAK LOW PRESSURE OVER THE LOWER GREAT LAKES WILL TURN SOUTHEASTWARD
AND IT SHOULD PASS OFF THE VIRGINIA COAST LATE TONIGHT. WEAK HIGH
PRESSURE FROM THE NORTHWEST AND NORTH IS ANTICIPATED TO FOLLOW FOR
THURSDAY THROUGH SATURDAY. A WARM FRONT APPROACHING FROM THE
SOUTHWEST WILL LIFT THROUGH OUR REGION ON SUNDAY OR SUNDAY NIGHT
WITH A COLD FRONT FROM THE NORTHWEST EXPECTED TO ARRIVE ON MONDAY
NIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
EARLY THIS MORNING...ESTF UPDATE AT 630 AM LOWERED POPS NE NJ AND
THE NJ CWATERS TODAY. FCST SEEMS ON TRACK ATTM. GFS/UKMET/ECMWF
ARE THE DRIVERS OF THE FCST. LOWERED THE CHC OF THUNDER BY ONE
CATEGORY.
TODAY...LOOKING LIKE A HEAVY RAIN EVENT FOR PTNS SE PA THRU THE
DELMARVA OR SNJ VCNTY KRDG-KPHL-KACY SWWD WITH 21Z/27 SREF PROBS FOR
1 INCH OF RAIN...PWAT BUILDING TO 2.1 INCHES OVER DELMARVA...SLOW -
10 KT - NW-W STEERING CURRENTS AND A SHORT WAVE LIFTING MOISTURE
OVER A SHALLOW CONVERGENCE ZONE NEAR SFC LOW PRES SOMEWHERE OVER E
MD DE. WHILE SVR TSTMS ARE UNLIKELY DUE TO WEAK SHEAR AND TT UNDER
48C...GULLY WASHERS ARE LIKELY WITH KI IN THE MID 30S THIS AFTN
THERE...SWI NEAR -2 AND A NEAR 90F AIRMASS IN THE WARM SECTOR. ML
CAPE WILL BE NEAR 1400J WHERE AND WHEN ITS NOT INITIALLY NOT RAINING
DURING MIDDAY. LIGHT WIND.
THE 00Z/28 RGEM/GGEM LOOK TOO FAR NORTH WITH THEIR FCST QPF
BULLSEYES.
THIS FCST IS A 50 50 BLEND OF THE GFS/NAM ELEMENTS WITH SOME RGEM IN
THE SKYCOVER PTN OF THE FCST. NO SREF INPUT INTO THE POP BUT THE
NEAR TERM PTN OF THIS FCST HAS A RELIANCE ON THE RAP MODEL GUIDANCE
AS SEEN IN THE CONSTANTLY MODEL UPDATED COSPA PRODUCT.
HPCQPF 06Z GRIDS WERE USED...WHICH FORCED THE BOX WX TOOL WORDING OF
HEAVY RAIN POSSIBLE FROM JUST SW OF KPHL S AND WEST TODAY.
FOR THUNDER...USED THE KI 36 (BLENDED 00Z/28 NAM/GFS KI) FOR
THUNDER. THAT KEEPS THUNDER LIMITED INLAND.
WE DID REVIEW THE 00Z/28 SPCWRF FOR TIMING CONVECTION AND ALSO THE
NSSL WRF QPF FCST (TTN-CMAY AXIS WHICH LOOKS TOO FAR NE BUT ISOLATED
3 INCH AMTS).
NO FLASH FLOOD WATCH. HOURLY FFG OVER 2.5 INCHES AND 6 HRLY IS
GENERALLY OVER 4.5 INCHES. MY CONCERN WITH RESPECT TO FFG...CHESTER
COUNTY PA AND NEW CASTLE DE. HOWEVER THAT DOESNT RULE OUT OTHER
COUNTIES. ITS WHERE ANY TSTMS REPEAT OR ARE QSTNRY THIS AFTN.
CONFIDENCE: AVERAGE
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
LEFTOVER CONVECTION DURING THE EVENING...MAINLY TO THE S OF KPHL.
THEN FOG AND STRATUS OVERNIGHT WITH POTENTIAL FOR 1/4MI DENSE FOG IN
PLACES WITH LIGHT WIND AND CLEARING ALOFT LEAVING THE MOIST BL
EXPOSED TO SATURATION. USED THE UPS CROSSOVER TOOL FOR FOG AFTER
06Z.
CONFIDENCE: ABOVE AVERAGE.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
ALOFT...THE PERIOD STARTS OFF WITH A NORTHWEST FLOW. AS THE BIG
RIDGE TO OUR WEST BECOMES SUPPRESSED ON SATURDAY, THE FLOW OVER THE
MID-ATLANTIC BECOMES MORE WESTERLY. THE FLOW TURNS MORE
SOUTHWESTERLY ON MONDAY AND TUESDAY AS A TROF MOVES THROUGH.
AT THE SURFACE...WEAK HIGH PRESSURE WILL BE IN PLACE THURSDAY THROUGH
SATURDAY. A WARM WILL MOVE THROUGH ON SUNDAY. A COLD FRONT WILL
FOLLOW ON MONDAY NIGHT.
PRECIPITATION...LOTS OF SMALL POPS(20/30%) THROUGH SUNDAY WITH THE
HIGHEST POPS ACROSS THE I-95 CORRIDOR WESTWARD AND DURING THE
AFTERNOON AND EVENING. WITH A COLD FRONT APPROACHING ON MONDAY AND
MOVING THROUGH MONDAY NIGHT, POPS ARE EVENLY DISTRIBUTED.
EVEN THOUGH WEAK HIGH PRESSURE IS IN PLACE, MODELS HAVE BEEN PUSHING
PRECIP ACROSS THE INTERIOR LATE THIS WEEK AND INTO THE WEEKEND FOR A
COUPLE DAYS. WITH WEAK S/W`S MOVING ACROSS THE TOP OF US COMBINED
WITH AFTERNOON INSTABILITY AND SHALLOW MOISTURE CONVERGENCE, IT
SEEMS REASONABLE. THE ONLY REAL CHANGE I MADE IN THE GRIDS THIS
MORNING WAS TO FOCUS MORE ON THE INTERIOR. THOSE VISITING THE
BEACHES MAY NOT SEE A DROP. AND THOSE FURTHER INLAND, THE FORECAST
WILL SOUND WETTER THAN REALITY.
TEMPERATURES...AROUND NORMAL THROUGH MONDAY. SLIGHTLY BELOW NORMAL
ON TUESDAY.
&&
.AVIATION /10Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
EARLY THIS MORNING PRIOR TO 12Z...VFR WITH SCT-BKN CLOUDS AOA 5000
FT DEVELOPING. PATCHY MVFR OR IFR FOG POSSIBLE NEAR KMIV AND KABE.
TODAY AFTER 12Z...VFR CIGS. ANY MVFR MORNING FOG WILL BURN OFF BY
14Z. LIGHT WIND. SHOWERS AND SCT TSTMS EXPECTED MOST TAF SITES FOR
1-4 HOURS. MOST LIKELY AREA FOR TSTMS IS VCNTY KRDG- KPHL- KILG-
KMIV. THE 06Z TAFS HAVE 3SM MDT SHOWERS WHERE MY CONFIDENCE IS
GREATEST FOR CONVECTION BUT NO MENTION OF TSTM ATTM DESPITE MY
EXPECTATION THAT KRDG/KPHL/KILG WILL RECORD A TSTM TODAY.
CONFIDENCE ON DETAILS: AVERAGE.
TONIGHT...VFR CIGS OR MVFR CONDS IN FOG/SCT SHOWERS AND ISO TSTMS
DIMINISHING EARLY WITH IFR CONDS IN ST/FOG APPEARING LIKELY LATE
FOR MOST TAF SITES. 21Z/27 SREF PROBS FOR THIS IFR OCCURRENCE ARE
ABOUT 40-50 PCT FOCUSED ON KMIV-KPHL AXIS. CONFIDENCE ON CIGS/VSBY
EARLY IS BELOW AVG. CONFIDENCE ON SOME SORT OF IFR IN FOG/STRATUS
LATE IS ABOVE AVERAGE...MAINLY AFTER 06Z.
OUTLOOK...
THURSDAY...MAINLY VFR. THERE IS A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS ON THURSDAY AFTERNOON.
THURSDAY NIGHT...MAINLY VFR WITH LATE NIGHT AND EARLY MORNING
VISIBILITY RESTRICTIONS POSSIBLE.
FRIDAY...MAINLY VFR. THERE IS A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS ON THURSDAY AFTERNOON.
FRIDAY NIGHT...MAINLY VFR WITH LATE NIGHT AND EARLY MORNING
VISIBILITY RESTRICTIONS POSSIBLE.
SATURDAY THROUGH SUNDAY...MAINLY VFR WITH LATE NIGHT AND EARLY
MORNING VISIBILITY RESTRICTIONS POSSIBLE. THERE IS A CHANCE OF
MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS.
&&
.MARINE...
NO HEADLINES THROUGH TONIGHT.
ATLC SEAS WILL CONTINUE TO RUN AROUND 1-3 FEET.
LIGHT AND VARIABLE WINDS TREND SOUTHERLY OR SOUTHEASTERLY DURING
THE DAY THEN EVENTUALLY NE TONIGHT.
NE GUSTS 15-20 KT POSSIBLE S NJ AND DE COASTS NEAR DAYBREAK
THURSDAY.
OUTLOOK...
WEAK HIGH PRESSURE CAN BE EXPECTED THURSDAY THROUGH SATURDAY. A WARM
FRONT WILL MOVE ACROSS THE WATERS FROM THE SOUTHWEST ON SUNDAY. WIND
SPEEDS AND WAVE HEIGHTS ARE EXPECTED TO REMAIN BELOW THE SMALL CRAFT
ADVISORY CRITERIA THROUGH THE PERIOD.
&&
.RIP CURRENTS...
TODAY...LOW RISK DOES NOT MEAN NO RISK BUT ITS BEEN A LOW RISK
SUMMER IN OUR FCST AREA SINCE THE ATLANTIC TROPICAL BASIN HAS BEEN
NOTABLY QUIET...DESPITE A FEW NAMED STORMS THAT JUST HAVENT SENT
MUCH SWELL UP OUR WAY.
THURSDAY...CURRENTLY IS OUTLOOKED LOW RISK BUT IF NE WINDS AVG 20
KT ALONG THE DE COAST...THIS COULD RESULT IN A MDT RISK THERE WITH
A HIGHER THAN MODELED SWELL. SO THERE IS RISK UNCERTAINTY FOR THURSDAY.
FRIDAY THROUGH MONDAY OUTLOOK AS LOW RISK DAYS.
&&
.CLIMATE...
TODAY`S HIGH TEMPERATURE AT PHILADELPHIA INTERNATIONAL AIRPORT
THROUGH 500 PM WAS 89 DEGREES. THIS MATCHES THE HIGH TEMPERATURE
WHICH OCCURRED BACK ON THE 21ST.
IF THE TEMPERATURE AT PHILADELPHIA DOES NOT REACH 90 DEGREES THIS
MONTH, IT WILL BE THE FIRST AUGUST SINCE 1984 WITHOUT AT 90 DEGREE
READING. IT IS RATHER UNUSUAL FOR THERE NOT BE AT LEAST ONE 90
DEGREE READING AT PHILADELPHIA DURING THE MONTH OF AUGUST. IT HAS
HAPPENED ONLY 5 TIMES OVER THE PAST CENTURY, IN 1920, 1927, 1934,
1963 AND 1984.
THE MONTH OF AUGUST SHOULD END UP AVERAGING BETWEEN 1.6 AND 2
DEGREES BELOW AVG FOR PHILADELPHIA.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KRUZDLO
NEAR TERM...DRAG 619A
SHORT TERM...DRAG
LONG TERM...KRUZDLO
AVIATION...DRAG/KRUZDLO 619A
MARINE...DRAG/KRUZDLO 619A
RIP CURRENTS...
CLIMATE...619A
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1028 AM CDT WED AUG 28 2013
.UPDATE...
ISSUED AT 1019 AM CDT WED AUG 28 2013
THE BACK DOOR COOL FRONT IS INTO THE NORTHERN CWFA WITH LOW CLOUDS
IMMEDIATELY BEHIND IT. BASED ON THE 12Z SOUNDING FROM GRB AND
SATELLITE TRENDS...BREAKING UP OF THE CLOUDS OVER THE NORTHERN
CWFA APPEARS QUESTIONABLE THIS AFTERNOON.
AS SUCH...CLOUDS HAVE BEEN INCREASED ACROSS THE NORTH AND
TEMPERATURES LOWERED SOMEWHAT. TEMPERATURES UP NORTH WILL BE
INTERESTING TODAY. IF A SCENARIO SIMILAR TO YESTERDAY IN WISCONSIN
PLAYS OUT THEN SOME AREAS UP NORTH MAY STRUGGLE TO GET MUCH ABOVE
80...OR GET INTO THE 80S AND THEN COLLAPSE BACK INTO THE MID AND
UPPER 70S ONCE THE FRONT MOVES THROUGH.
DIURNAL HEATING AHEAD OF THE FRONT SHOULD SLOW THE SOUTHWARD
PROGRESS OF THE CLOUDS WITH THE FRONT POTENTIALLY STALLING OUT
DURING THE AFTERNOON. CONVERGENCE ALONG THE FRONT IS QUITE WEAK
BUT ONE CANNOT ENTIRELY RULE OUT AN ISOLATED SHOWER OR STORM DUE
TO THE STRONG DIFFERENTIAL HEATING. AS SUCH 10-14 POPS WERE
GENERALLY DONE IN THE VICINITY OF THE FRONT.
THE CURRENT HEAT HEADLINES WILL REMAIN AS IS. THERE ARE QUESTIONS
AS TO WHETHER OR NOT THE NORTHERN EXTEND OF THE ADVISORY AREA WILL
SEE HEAT INDEX READINGS OF 100 DUE TO THE CLOUDS AND FRONTAL
POSITION. ..08..
&&
.SYNOPSIS...
ISSUED AT 341 AM CDT WED AUG 28 2013
MSAS SURFACE ANALYSIS AT 07Z INDICATED THE SURFACE COOL FRONT
REACHING WEST FROM LOW PRESSURE OVER SE LOWER MI ACROSS SOUTHERN
WI...FAR NORTHERN IA...TO A WEAK LOW NW OF VALENTINE NE. SURFACE
DEWPOINTS WERE POOLING IN THE LOWER 70S ALONG AND SOUTH OF THIS AXIS
TO THE HIGHWAY 20 CORRIDOR...WHILE FURTHER SOUTH...MID TO UPPER 60S
WERE COMMON ACROSS THE MUCH OF THE FORECAST AREA. FOG CHANNEL
SATELLITE IMAGERY INDICATED A LARGE FIELD OF POST FRONTAL STRATUS
AND FOG ADVECTING W-SW ACROSS WI...WHILE HINTS OF STRATUS WERE
STARTING TO SHOW UP AHEAD OF THE FRONT BETWEEN KOLZ AND KCGY IN NE
IA. OTHERWISE...IT WAS ANOTHER VERY WARM AND SOMEWHAT MUGGY NIGHT
ACROSS THE REGION WITH TEMPERATURES STILL IN THE MID TO UPPER 70S
AT 3 AM.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 341 AM CDT WED AUG 28 2013
MANY CHALLENGES IN THE FORECAST FOR TODAY AS THE TIMING OF FRONT AND
POSSIBLE CLOUDS WILL IMPACT TEMPERATURES...HUMIDITY AND THE HEAT
ADVISORY HEADLINES.
HAVE FOLLOWED A BLEND OF THE 00Z GFS AND ECMWF BRINGING THE FRONT
INTO FAR NW IL AND EAST CENTRAL IA BY LATE MORNING...THEN
STALLING TO ROUGHLY BISECT THE FORECAST AREA FROM NW TO SE BY
EVENING. ASSOCIATED LOW LEVEL MOISTURE CONVERGENCE WILL KEEP
SURFACE DEWPOINTS IN THE LOWER 70S FOR MUCH OF THE DAY ALONG AND
NE OF THE BOUNDARY WITH THERMAL MIXING IN THE LOW LEVEL NE FLOW
EXPECTED TO BE LIMITED TO AROUND 900 MB. ALONG AND SOUTHWEST OF
THE FRONT...ANOTHER DAY OF DEEP MIXING WITH SIMILAR 850 MB
TEMPERATURES AS YESTERDAY SHOULD YIELD SIMILAR HIGHS...WHILE
DEWPOINTS STAY A FEW DEGREES LOWER. BIG QUESTION WILL BE WHAT
HAPPENS WITH THE BACKDOOR POST FRONTAL STRATUS DECK CURRENTLY
RACING TOWARD THE AREA FROM WI...WHICH AT THE PRESENT RATE IS
SHOWN REACHING NW IL BY 7 AM. THE EARLIER RAP RUNS APPEARED TO
HAVE THE BEST HANDLE ON THIS MOIST AXIS AROUND 925 TO 900
MB...SHOWING IT REACHING INTO THE HIGHWAY 20 CORRIDOR EARLY THIS
MORNING...THEN WASHING OUT WITH DAYTIME HEATING AND WILL FOLLOW
THIS SCENARIO FOR NOW COUNTING ON MOSTLY SUNNY SKIES OVER THE
ENTIRE AREA MOST OF THE DAY.
WILL THUS HAVE HIGHS FROM THE MID 80S ACROSS THE NORTHEAST...90 TO
LOWER 90S ACROSS THE CENTRAL THIRD...THEN MID 90S IN THE SOUTH.
THIS MAY AGAIN THREATEN RECORD HIGHS FOR THIS DATE...ESPECIALLY AT
BRL...LISTED IN THE CLIMATE SECTION BELOW. WHEN COMBINED WITH
SURFACE DEWPOINTS LINGERING IN THE LOWER TO MID 70S WHERE THE
FRONT EVENTUALLY STALLS OUT...HEAT INDEX VALUES SHOULD EXCEED 100
BY AFTERNOON. WELL SOUTHWEST OF THE FRONT...DEWPOINTS WILL BE
LOWER...BUT AMBIENT TEMPERATURES INTO THE MID AND POSSIBLY UPPER
90S WILL RESULT IN WIDESPREAD 100 TO 103 HEAT INDEX VALUES IN THE
AFTERNOON. HAVE KEPT THE PREVIOUS HEAT ADVISORY GOING UNTIL 00Z AND
ADDED BUCHANAN AND JONES COUNTY IN EASTERN IA WHERE THE HEAT INDEX
NOW LOOKS LIKELY TO EXCEED 100.
WHILE SOME MODELS ARE ADVERTISING QPF ALONG AND NE OF THE BOUNDARY
TODAY AND TONIGHT...THIS LOOKS OVERDONE GIVEN THE CAPPING WARM
TEMPERATURES ALOFT. THIS CAP WEAKENS SOME TONIGHT...BUT WITH A
STRONG TRIGGER LACKING...WILL KEEP A DRY FORECAST. WITH THE FRONT
LINGERING OVER THE AREA...WARM AND SOMEWHAT HUMID AIR WILL REMAIN IN
PLACE OVER ESPECIALLY THE CENTRAL AND SOUTH. HAVE KEPT LOWS FROM THE
MID 60S NORTHEAST TO THE LOWER 70S ACROSS THE SOUTH.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 341 AM CDT WED AUG 28 2013
FORECAST FOCUS ON HOT AND HUMID AND MAINLY DRY THROUGH SATURDAY...
THEN MUCH COOLER BY LABOR DAY.
THURSDAY THROUGH SATURDAY NIGHT...RIDGING ALOFT AND A CAPPED
ATMOSPHERE TO REMAIN THROUGH MUCH OF THIS TIME FRAME. THERE IS A
SMALL CHANCE OF THUNDERSTORMS MAINLY FRIDAY NIGHT AS A RIDGE RIDER
TRACKS ACROSS THE MIDWEST. THE SURFACE BOUNDARY WILL LIFT BACK TO
THE NORTHEAST OF THE CWA BY FRIDAY. MAXIMUM TEMPERATURES ON THURSDAY
WILL BE IN THE UPPER 80S NORTHEAST TO THE MID 90S SOUTHWEST...AND IN
THE 90S OVER ALL THE CWA BOTH FRIDAY AND SATURDAY. THESE WILL BE
SCORCHERS WITH DEWPOINTS AT LEAST IN THE LOWER 70S. HIGHEST HEAT
INDEX VALUES LOOK TO BE 100 TO 105 IN OUR SOUTHERN COUNTIES ON
THURSDAY...AND OVER MUCH OF THE CWA FOR BOTH FRIDAY AND SATURDAY.
HEAT ADVISORY HEADLINES WILL MORE THAN LIKELY NEED TO BE ISSUED FOR
MUCH OF THIS PERIOD. IF BURLINGTON IOWA RECEIVES NO RAINFALL BY THE
END OF THIS MONTH THEY WILL GO INTO THE BOOKS WITH ONLY A TRACE OF
RAIN FOR THE ENTIRE MONTH OF AUGUST...AND THE DRIEST AUGUST ON
RECORD!
SUNDAY AND SUNDAY NIGHT...TIMING OF THE COLD FRONT WILL BE CRITICAL
AS FAR AS CHANCES FOR THUNDERSTORMS AND MAXIMUM TEMPERATURES. DID
NOTICE THE ECMWF HAS BACKED OFF ON THE REALLY CHILLY AIR FROM A
COUPLE OF RUNS AGO. NOW THE ECMWF BRINGS ONLY THE 8C 850 MB
TEMPERATURE AS FAR SOUTH AS NORTHERN IL INSTEAD OF THE 2C FROM
EARLIER RUNS. CURRENT GRID TEMPERATURES MAY BE TOO WARM ON SUNDAY
DEPENDING ON TIMING OF THE FRONT...AMOUNT OF CLOUD COVER AND ANY
RAINFALL. THERE DOES APPEAR TO BE AT LEAST A CHANCE FOR A FEW
THUNDERSTORMS TO FORM ALONG THE FRONT BUT IN A DRY SPELL YOU DON`T
WANT TO GET YOUR HOPES UP. BUT ONCE AGAIN THIS WILL DEPEND ON THE
TIMING OF THE FRONT AND AMOUNT OF INSTABILITY AND MOISTURE. WELL...
AT LEAST ON PAPER THERE IS ENOUGH FORCING FROM THE DIGGING TROUGH TO
HOPEFULLY TRIGGER AT LEAST SCATTERED STORMS.
NEXT WEEK...HIGH PRESSURE WILL BRING A PLEASANT LABOR DAY AND THE
EARLY PART OF THE SHORTENED WORK WEEK. SHOULD BE A REALLY NICE DAY
FOR GRILLING OUT IN THE BACKYARD. MAXIMUM TEMPERATURES SHOULD END UP
IN THE 70S NORTH AND 80S SOUTH ALONG WITH COMFORTABLE HUMIDITY.
NIGHTTIME LOWS WILL DROP INTO THE 50S TO LOWER 60S EARLY IN THE
WEEK. ACCORDING TO MY FAVORED ECMWF MODEL THERE WILL BE A BRIEF WARM
UP BY MID WEEK FOLLOWED SHORTLY THEREAFTER BY ANOTHER COLD FRONT.
HOWEVER...MUCH OF THE FIRST WEEK OF SEPTEMBER LOOKS ON THE DRY SIDE.
HAASE
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 626 AM CDT WED AUG 28 2013
A COLD FRONT MOVING IN FROM THE NORTH IS INCREASINGLY LOOKING LIKE
IT WILL SPREAD LOW CLOUDS INTO THE DBQ AREA THIS MORNING AND HAVE
ADDED A TEMPO GROUP FOR A CIG BELOW 1000 FT. THESE CLOUDS APPEAR
TO BE THIN AND WILL LIKELY BREAK UP BY MID MORNING TO GIVE WAY TO
PREVAILING VFR CONDITIONS ACROSS THE AREA TODAY. WINDS WILL BE
LIGHT AND GRADUALLY VEER FROM WEST TO NORTHWEST...TO NORTHEAST
WITH THE FRONTAL PASSAGE. TONIGHT...LIGHT WINDS AND LINGERING LOW
LEVEL MOISTURE WILL LIKELY LEAD TO AREAS OF FOG. FOR NOW HAVE
BROUGHT IN PERIODS OF MVFR VISIBILITY TOWARD MORNING. LATER
FORECASTS MAY BRING IN EVEN LOWER VISIBILITIES AS FORECAST
CONFIDENCE INCREASES.
&&
.CLIMATE...
ISSUED AT 341 AM CDT WED AUG 28 2013
RECORD HIGHS FOR AUGUST 28...
MOLINE.........96 IN 1953
CEDAR RAPIDS...96 IN 1955
DUBUQUE........97 IN 1984
BURLINGTON.....96 IN 1945
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR BENTON-BUCHANAN-
CEDAR-DES MOINES-HENRY IA-IOWA-JEFFERSON-JOHNSON-JONES-
KEOKUK-LEE-LINN-LOUISA-MUSCATINE-SCOTT-VAN BUREN-WASHINGTON.
IL...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR HANCOCK-HENDERSON-
HENRY IL-MCDONOUGH-MERCER-ROCK ISLAND-WARREN.
MO...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR CLARK-SCOTLAND.
&&
$$
UPDATE...08
SYNOPSIS...SHEETS
SHORT TERM...SHEETS
LONG TERM...12
AVIATION...SHEETS
CLIMATE...SHEETS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
626 AM CDT WED AUG 28 2013
.SYNOPSIS...
ISSUED AT 341 AM CDT WED AUG 28 2013
MSAS SURFACE ANALYSIS AT 07Z INDICATED THE SURFACE COOL FRONT
REACHING WEST FROM LOW PRESSURE OVER SE LOWER MI ACROSS SOUTHERN
WI...FAR NORTHERN IA...TO A WEAK LOW NW OF VALENTINE NE. SURFACE
DEWPOINTS WERE POOLING IN THE LOWER 70S ALONG AND SOUTH OF THIS AXIS
TO THE HIGHWAY 20 CORRIDOR...WHILE FURTHER SOUTH...MID TO UPPER 60S
WERE COMMON ACROSS THE MUCH OF THE FORECAST AREA. FOG CHANNEL
SATELLITE IMAGERY INDICATED A LARGE FIELD OF POST FRONTAL STRATUS
AND FOG ADVECTING W-SW ACROSS WI...WHILE HINTS OF STRATUS WERE
STARTING TO SHOW UP AHEAD OF THE FRONT BETWEEN KOLZ AND KCGY IN NE
IA. OTHERWISE...IT WAS ANOTHER VERY WARM AND SOMEWHAT MUGGY NIGHT
ACROSS THE REGION WITH TEMPERATURES STILL IN THE MID TO UPPER 70S
AT 3 AM.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 341 AM CDT WED AUG 28 2013
MANY CHALLENGES IN THE FORECAST FOR TODAY AS THE TIMING OF FRONT AND
POSSIBLE CLOUDS WILL IMPACT TEMPERATURES...HUMIDITY AND THE HEAT
ADVISORY HEADLINES.
HAVE FOLLOWED A BLEND OF THE 00Z GFS AND ECMWF BRINGING THE FRONT
INTO FAR NW IL AND EAST CENTRAL IA BY LATE MORNING...THEN
STALLING TO ROUGHLY BISECT THE FORECAST AREA FROM NW TO SE BY
EVENING. ASSOCIATED LOW LEVEL MOISTURE CONVERGENCE WILL KEEP
SURFACE DEWPOINTS IN THE LOWER 70S FOR MUCH OF THE DAY ALONG AND
NE OF THE BOUNDARY WITH THERMAL MIXING IN THE LOW LEVEL NE FLOW
EXPECTED TO BE LIMITED TO AROUND 900 MB. ALONG AND SOUTHWEST OF
THE FRONT...ANOTHER DAY OF DEEP MIXING WITH SIMILAR 850 MB
TEMPERATURES AS YESTERDAY SHOULD YIELD SIMILAR HIGHS...WHILE
DEWPOINTS STAY A FEW DEGREES LOWER. BIG QUESTION WILL BE WHAT
HAPPENS WITH THE BACKDOOR POST FRONTAL STRATUS DECK CURRENTLY
RACING TOWARD THE AREA FROM WI...WHICH AT THE PRESENT RATE IS
SHOWN REACHING NW IL BY 7 AM. THE EARLIER RAP RUNS APPEARED TO
HAVE THE BEST HANDLE ON THIS MOIST AXIS AROUND 925 TO 900
MB...SHOWING IT REACHING INTO THE HIGHWAY 20 CORRIDOR EARLY THIS
MORNING...THEN WASHING OUT WITH DAYTIME HEATING AND WILL FOLLOW
THIS SCENARIO FOR NOW COUNTING ON MOSTLY SUNNY SKIES OVER THE
ENTIRE AREA MOST OF THE DAY.
WILL THUS HAVE HIGHS FROM THE MID 80S ACROSS THE NORTHEAST...90 TO
LOWER 90S ACROSS THE CENTRAL THIRD...THEN MID 90S IN THE SOUTH.
THIS MAY AGAIN THREATEN RECORD HIGHS FOR THIS DATE...ESPECIALLY AT
BRL...LISTED IN THE CLIMATE SECTION BELOW. WHEN COMBINED WITH
SURFACE DEWPOINTS LINGERING IN THE LOWER TO MID 70S WHERE THE
FRONT EVENTUALLY STALLS OUT...HEAT INDEX VALUES SHOULD EXCEED 100
BY AFTERNOON. WELL SOUTHWEST OF THE FRONT...DEWPOINTS WILL BE
LOWER...BUT AMBIENT TEMPERATURES INTO THE MID AND POSSIBLY UPPER
90S WILL RESULT IN WIDESPREAD 100 TO 103 HEAT INDEX VALUES IN THE
AFTERNOON. HAVE KEPT THE PREVIOUS HEAT ADVISORY GOING UNTIL 00Z AND
ADDED BUCHANAN AND JONES COUNTY IN EASTERN IA WHERE THE HEAT INDEX
NOW LOOKS LIKELY TO EXCEED 100.
WHILE SOME MODELS ARE ADVERTISING QPF ALONG AND NE OF THE BOUNDARY
TODAY AND TONIGHT...THIS LOOKS OVERDONE GIVEN THE CAPPING WARM
TEMPERATURES ALOFT. THIS CAP WEAKENS SOME TONIGHT...BUT WITH A
STRONG TRIGGER LACKING...WILL KEEP A DRY FORECAST. WITH THE FRONT
LINGERING OVER THE AREA...WARM AND SOMEWHAT HUMID AIR WILL REMAIN IN
PLACE OVER ESPECIALLY THE CENTRAL AND SOUTH. HAVE KEPT LOWS FROM THE
MID 60S NORTHEAST TO THE LOWER 70S ACROSS THE SOUTH.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 341 AM CDT WED AUG 28 2013
FORECAST FOCUS ON HOT AND HUMID AND MAINLY DRY THROUGH SATURDAY...
THEN MUCH COOLER BY LABOR DAY.
THURSDAY THROUGH SATURDAY NIGHT...RIDGING ALOFT AND A CAPPED
ATMOSPHERE TO REMAIN THROUGH MUCH OF THIS TIME FRAME. THERE IS A
SMALL CHANCE OF THUNDERSTORMS MAINLY FRIDAY NIGHT AS A RIDGE RIDER
TRACKS ACROSS THE MIDWEST. THE SURFACE BOUNDARY WILL LIFT BACK TO
THE NORTHEAST OF THE CWA BY FRIDAY. MAXIMUM TEMPERATURES ON THURSDAY
WILL BE IN THE UPPER 80S NORTHEAST TO THE MID 90S SOUTHWEST...AND IN
THE 90S OVER ALL THE CWA BOTH FRIDAY AND SATURDAY. THESE WILL BE
SCORCHERS WITH DEWPOINTS AT LEAST IN THE LOWER 70S. HIGHEST HEAT
INDEX VALUES LOOK TO BE 100 TO 105 IN OUR SOUTHERN COUNTIES ON
THURSDAY...AND OVER MUCH OF THE CWA FOR BOTH FRIDAY AND SATURDAY.
HEAT ADVISORY HEADLINES WILL MORE THAN LIKELY NEED TO BE ISSUED FOR
MUCH OF THIS PERIOD. IF BURLINGTON IOWA RECEIVES NO RAINFALL BY THE
END OF THIS MONTH THEY WILL GO INTO THE BOOKS WITH ONLY A TRACE OF
RAIN FOR THE ENTIRE MONTH OF AUGUST...AND THE DRIEST AUGUST ON
RECORD!
SUNDAY AND SUNDAY NIGHT...TIMING OF THE COLD FRONT WILL BE CRITICAL
AS FAR AS CHANCES FOR THUNDERSTORMS AND MAXIMUM TEMPERATURES. DID
NOTICE THE ECMWF HAS BACKED OFF ON THE REALLY CHILLY AIR FROM A
COUPLE OF RUNS AGO. NOW THE ECMWF BRINGS ONLY THE 8C 850 MB
TEMPERATURE AS FAR SOUTH AS NORTHERN IL INSTEAD OF THE 2C FROM
EARLIER RUNS. CURRENT GRID TEMPERATURES MAY BE TOO WARM ON SUNDAY
DEPENDING ON TIMING OF THE FRONT...AMOUNT OF CLOUD COVER AND ANY
RAINFALL. THERE DOES APPEAR TO BE AT LEAST A CHANCE FOR A FEW
THUNDERSTORMS TO FORM ALONG THE FRONT BUT IN A DRY SPELL YOU DON`T
WANT TO GET YOUR HOPES UP. BUT ONCE AGAIN THIS WILL DEPEND ON THE
TIMING OF THE FRONT AND AMOUNT OF INSTABILITY AND MOISTURE. WELL...
AT LEAST ON PAPER THERE IS ENOUGH FORCING FROM THE DIGGING TROUGH TO
HOPEFULLY TRIGGER AT LEAST SCATTERED STORMS.
NEXT WEEK...HIGH PRESSURE WILL BRING A PLEASANT LABOR DAY AND THE
EARLY PART OF THE SHORTENED WORK WEEK. SHOULD BE A REALLY NICE DAY
FOR GRILLING OUT IN THE BACKYARD. MAXIMUM TEMPERATURES SHOULD END UP
IN THE 70S NORTH AND 80S SOUTH ALONG WITH COMFORTABLE HUMIDITY.
NIGHTTIME LOWS WILL DROP INTO THE 50S TO LOWER 60S EARLY IN THE
WEEK. ACCORDING TO MY FAVORED ECMWF MODEL THERE WILL BE A BRIEF WARM
UP BY MID WEEK FOLLOWED SHORTLY THEREAFTER BY ANOTHER COLD FRONT.
HOWEVER...MUCH OF THE FIRST WEEK OF SEPTEMBER LOOKS ON THE DRY SIDE.
HAASE
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 626 AM CDT WED AUG 28 2013
A COLD FRONT MOVING IN FROM THE NORTH IS INCREASINGLY LOOKING LIKE
IT WILL SPREAD LOW CLOUDS INTO THE DBQ AREA THIS MORNING AND HAVE
ADDED A TEMPO GROUP FOR A CIG BELOW 1000 FT. THESE CLOUDS APPEAR
TO BE THIN AND WILL LIKELY BREAK UP BY MID MORNING TO GIVE WAY TO
PREVAILING VFR CONDITIONS ACROSS THE AREA TODAY. WINDS WILL BE
LIGHT AND GRADUALLY VEER FROM WEST TO NORTHWEST...TO NORTHEAST
WITH THE FRONTAL PASSAGE. TONIGHT...LIGHT WINDS AND LINGERING LOW
LEVEL MOISTURE WILL LIKELY LEAD TO AREAS OF FOG. FOR NOW HAVE
BROUGHT IN PERIODS OF MVFR VISIBILITY TOWARD MORNING. LATER
FORECASTS MAY BRING IN EVEN LOWER VISIBILITIES AS FORECAST
CONFIDENCE INCREASES.
&&
.CLIMATE...
ISSUED AT 341 AM CDT WED AUG 28 2013
RECORD HIGHS FOR AUGUST 28...
MOLINE.........96 IN 1953
CEDAR RAPIDS...96 IN 1955
DUBUQUE........97 IN 1984
BURLINGTON.....96 IN 1945
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR BENTON-BUCHANAN-
CEDAR-DES MOINES-HENRY IA-IOWA-JEFFERSON-JOHNSON-JONES-
KEOKUK-LEE-LINN-LOUISA-MUSCATINE-SCOTT-VAN BUREN-WASHINGTON.
IL...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR HANCOCK-HENDERSON-
HENRY IL-MCDONOUGH-MERCER-ROCK ISLAND-WARREN.
MO...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR CLARK-SCOTLAND.
&&
$$
SYNOPSIS...SHEETS
SHORT TERM...SHEETS
LONG TERM...12
AVIATION...SHEETS
CLIMATE...SHEETS
AREA FORECAST DISCUSSION
NWS JACKSON KY
1044 AM EDT WED AUG 28 2013
.UPDATE...
ISSUED AT 1044 AM EDT WED AUG 28 2013
UPDATED THE FORECAST TO BETTER REFLECT CURRENT CONDITIONS AND MODEL
TRENDS. THE AIR OVER EASTERN KENTUCKY IS ONCE AGAIN UNSTABLE AND AS
YESTERDAY IS LOOKING FOR A TRIGGER TO GET THINGS GOING. NOT SEEING
ANYTHING DEFINITE...HOWEVER BY THE END OF THE DAY...THE FRONT WILL BE
GETTING CLOSER AND THIS COULD HELP TO GET SOME CONVECTION GOING IN
THIS PREFRONTAL ENVIRONMENT. THE MODELS WERE SHOWING SOME DECREASE IN
CLOUDS THIS AFTERNOON AND SO BUMPED THE HIGHS UP A LITTLE. ALSO MADE
SOME SLIGHT ADJUSTMENTS IN FOR TONIGHT AND TOMORROW BASED ON THE
LATEST MODELS.
UPDATE ISSUED AT 651 AM EDT WED AUG 28 2013
A FEW WIDELY ISOLATED SHOWERS ARE DEVELOPING ACROSS SOUTHEAST PIKE
COUNTY. COVERAGE IS VERY SMALL AT THIS TIME AND STORM MOVEMENT WILL
TAKE THIS ACTIVITY SOUTHEAST OF THE AREA IN THE NEXT HOUR. THUS...NO
PLANS TO INTRODUCE POPS AT THIS TIME. WILL MAKE SOME TWEAKS TO THE
HOURLY POPS TO ACCOUNT FOR THIS ACTIVITY. OTHERWISE...HRRR CONTINUES
TO SHOW A SIGNIFICANT LULL FOR THE AREA TODAY WITH A BAND OF ISOLATED
TO PERHAPS SCATTERED SHOWERS ARRIVING LATE (AFTER 20Z) IN THE DAY
FROM THE NORTH. GOING TO DEAL WITH SOME CLOUD COVER THIS MORNING FROM
THE DEBRIS OF AN OVERNIGHT MCS THAT WILL DRIFT SOUTH ACROSS THE AREA.
HOWEVER...CLOUD COVER SHOULD GIVE WAY TO A GOOD DOSE OF SUNSHINE BY
MID TO LATE MORNING...ALLOWING FOR THE ANTICIPATED WARM DAY. NO
UPDATE PLANNED AT THIS TIME...BUT AS MENTIONED...WILL FRESHEN UP THE
HOURLY GRIDS.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 307 AM EDT WED AUG 28 2013
A STRONG RIDGE CONTINUES TO DOMINATE FROM THE SOUTH CENTRAL US INTO
THE CENTRAL PLAINS. PRESENTLY...A SHORTWAVE ON THE PERIPHERALS OF THIS
RIDGE IS PUSHING SOUTHEAST ACROSS THE SOUTHERN GREAT LAKES. THIS WAVE
WILL BE THE FOCUS OF OUR WEATHER TODAY AS IT BRINGS A THREAT OF
SHOWERS AND A FEW THUNDERSTORMS BACK TO THE AREA. MODELS ALL HAVE
THIS SHORTWAVE PROGRESSING SOUTHEAST ACROSS THE EASTERN OHIO RIVER
VALLEY TODAY. HOWEVER...THERE ARE SOME DIFFERENCES ON EXACTLY HOW FAR
SOUTHWEST THIS SHORTWAVE WILL TRACK...AND ULTIMATELY...HOW FAR
SOUTHWEST THE HIGHER CHANCES FOR RAIN WILL REACH. 00Z NAM IS THE MOST
AGGRESSIVE BRINGING SCATTERED TO NUMEROUS SHOWERS ACROSS THE COAL
FIELDS TODAY. HOWEVER...LATEST HRRR DOESN`T SEEM TO SUPPORT THE NAM
EVEN TO A LITTLE DEGREE. MEANWHILE...THE ECMWF AND GFS BOTH SUGGEST
PRECIPITATION WILL BE CONFINED TO THE EASTERN MOST COUNTIES IN
KENTUCKY TODAY. GIVEN THE UNCERTAINTY...HARD TO GO VERY HIGH WITH THE
CHANCE OF RAIN TODAY...ESPECIALLY THE FARTHER WEST YOU GET. BEST
SHORTWAVE ENERGY PROBABLY WILL NOT ARRIVE UNTIL LATE IN THE DAY...SO
HAVE DELAYED POPS INTO THE EVENING HOURS...AND GONE WITH 20 PERCENT
CHANCES IN THE WEST TO 40 PERCENT IN THE FAR EAST. THERE IS A PRETTY
GOOD CHANCE THAT THESE POPS MAY BE TOO HIGH AS WE MAY HAVE A TOUGH
TIME GETTING DECENT COVERAGE. HIGHS TODAY WILL CLIMB INTO THE MID TO
UPPER 80S (AROUND 1 TO 2 DEGREES WARMER THAN YESTERDAY).
GOING TO MAINTAIN SOME SLIGHT POPS TONIGHT AS A WEAK BOUNDARY
ASSOCIATED WITH THE SHORTWAVE CONTINUES TO SAG SOUTHWARD. THIS
BOUNDARY SHOULD EXIT THE SOUTH ON THURSDAY...ALLOWING FOR A RAIN FREE
DAY. AN ISOLATED SHOWER COULD POP UP ALONG THE VIRGINIA OR TENNESSEE
BORDER BY LATE MORNING PRIOR TO THIS FRONT CLEARING THE AREA.
DESPITE THE BOUNDARY SAGGING SOUTH...TEMPERATURES WILL REMAIN JUST AS
WARM WITH HIGHS INTO THE MID TO UPPER 80S.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 307 AM EDT WED AUG 28 2013
THE UPPER LEVEL PATTERN DURING THE PERIOD WILL FEATURE A STRONG
UPPER LEVEL HIGH CENTERED NEAR THE TX/OK PANHANDLES...WITH TROUGHING
ON EITHER SIDE. THE AMPLITUDE OF THE PATTERN WILL FLUCTUATE AS UPPER
LOWS RIDE THROUGH THE WESTERLIES AROUND THE RIDGE. DEAMPLIFICATION
IS EXPECTED EARLY IN THE PERIOD...WITH REAMPLIFICATION TOWARD THE
END. THIS SET-UP PUTS OUR LOCAL AREA IN A GENERAL NW FLOW
ALOFT...FAVORING PERIODIC COLD FRONTAL PASSAGES. ONE FRONT WILL BE
EXITING TO OUR S AND SW AT THE START OF THE PERIOD. SLIGHTLY DRIER
AIR BEHIND THE FRONT SHOULD ALLOW FOR DRY WEATHER THROUGH FRIDAY
NIGHT.
THE FRONT WILL STALL AND WEAKEN AFTER IT PASSES...AND MORE HUMID AIR
WILL BE LOOMING JUST TO OUR S AND W. AS SURFACE HIGH PRESSURE
SLIPS AWAY TO OUR EAST...LOW LEVEL FLOW WILL SEND THIS AIR MASS BACK
INTO OUR AREA DURING THE WEEKEND. MODELS DO SHOW WEAK DISTURBANCES
ALOFT TRAVELING IN THE NW FLOW. COMBINED WITH INCREASING MOISTURE
AND WEAK ISENTROPIC LIFT...THIS MAY VERY WELL ALLOW SCATTERED
SHOWERS AND THUNDERSTORMS TO DEVELOP...AND 30-40 PERCENT POPS WILL
BE USED DURING THE WEEKEND.
AS THE NEXT UPPER LOW HEADS INTO THE GENERALIZED EAST CONUS
TROUGH...PATTERN AMPLIFICATION BEGINS BEFORE THE WEEKEND IS
FINISHED...AND THE REJUVENATED EAST CONUS TROUGH BRINGS ANOTHER COLD
FRONT SOUTHEAST TO OUR AREA. OUR BEST CHANCE AT PRECIP IS WITH
HEATING JUST AHEAD OF THE FRONT ON MONDAY. WILL STICK WITH HIGH
CHANCE POPS AT THIS POINT. THE BEST ESTIMATE FOR FROPA IS MONDAY
NIGHT AND POSSIBLY INTO EARLY TUESDAY. ANY PRECIP SHOULD END NW TO
SE AS DRIER AIR ARRIVES BEHIND THE FRONT. MODELS HAVE NOT BEEN
CONSISTENT CONCERNING THE DEGREE OF COOLING/DRYING BEHIND THIS
FRONT...AND A MODEL BLEND/AVERAGE WILL BE USED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 651 AM EDT WED AUG 28 2013
AN AREA OF 800-1000 FT STRATUS HAS FORMED OVER MUCH OF THE AREA THIS
MORNING ALONG WITH SOME PATCHY FOG. THE FOG/STRATUS MAY LINGER A BIT
LONGER THAN THE PAST FEW MORNINGS AS WE HAVE SOME MID/HIGH CLOUDS
DRIFTING IN FROM THE NORTH WHICH MAY SLOW THE WARMING PROCESS THIS
MORNING. WE SHOULD SEE THINGS RETURN TO MAINLY VFR BY MID TO LATE
MORNING AS TEMPERATURES FINALLY START TO WARM AND WE MIX OUT THE LOW
CLOUDS. A BAND OF ISOLATED SHOWERS MAY WORK INTO THE AREA LATE IN THE
DAY AND COULD AFFECT THE TAF SITES...BUT COVERAGE WILL BE VERY
LIMITED AND WILL NOT INTRODUCE SHOWERS AT THIS TIME. AS A WEAK
FRONTAL BOUNDARY PUSHES SOUTH LATE TONIGHT...ANOTHER ROUND OF VALLEY
FOG MAY BE POSSIBLE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JJ
SHORT TERM...KAS
LONG TERM...HAL
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
651 AM EDT WED AUG 28 2013
.UPDATE...
ISSUED AT 651 AM EDT WED AUG 28 2013
A FEW WIDELY ISOLATED SHOWERS ARE DEVELOPING ACROSS SOUTHEAST PIKE
COUNTY. COVERAGE IS VERY SMALL AT THIS TIME AND STORM MOVEMENT WILL
TAKE THIS ACTIVITY SOUTHEAST OF THE AREA IN THE NEXT HOUR. THUS...NO
PLANS TO INTRODUCE POPS AT THIS TIME. WILL MAKE SOME TWEAKS TO THE
HOURLY POPS TO ACCOUNT FOR THIS ACTIVITY. OTHERWISE...HRRR CONTINUES
TO SHOW A SIGNIFICANT LULL FOR THE AREA TODAY WITH A BAND OF ISOLATED
TO PERHAPS SCATTERED SHOWERS ARRIVING LATE (AFTER 20Z) IN THE DAY
FROM THE NORTH. GOING TO DEAL WITH SOME CLOUD COVER THIS MORNING FROM
THE DEBRIS OF AN OVERNIGHT MCS THAT WILL DRIFT SOUTH ACROSS THE AREA.
HOWEVER...CLOUD COVER SHOULD GIVE WAY TO A GOOD DOSE OF SUNSHINE BY
MID TO LATE MORNING...ALLOWING FOR THE ANTICIPATED WARM DAY. NO
UPDATE PLANNED AT THIS TIME...BUT AS MENTIONED...WILL FRESHEN UP THE
HOURLY GRIDS.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 307 AM EDT WED AUG 28 2013
A STRONG RIDGE CONTINUES TO DOMINATE FROM THE SOUTH CENTRAL US INTO
THE CENTRAL PLAINS. PRESENTLY...A SHORTWAVE ON THE PERIPHERALS OF THIS
RIDGE IS PUSHING SOUTHEAST ACROSS THE SOUTHERN GREAT LAKES. THIS WAVE
WILL BE THE FOCUS OF OUR WEATHER TODAY AS IT BRINGS A THREAT OF
SHOWERS AND A FEW THUNDERSTORMS BACK TO THE AREA. MODELS ALL HAVE
THIS SHORTWAVE PROGRESSING SOUTHEAST ACROSS THE EASTERN OHIO RIVER
VALLEY TODAY. HOWEVER...THERE ARE SOME DIFFERENCES ON EXACTLY HOW FAR
SOUTHWEST THIS SHORTWAVE WILL TRACK...AND ULTIMATELY...HOW FAR
SOUTHWEST THE HIGHER CHANCES FOR RAIN WILL REACH. 00Z NAM IS THE MOST
AGGRESSIVE BRINGING SCATTERED TO NUMEROUS SHOWERS ACROSS THE COAL
FIELDS TODAY. HOWEVER...LATEST HRRR DOESN`T SEEM TO SUPPORT THE NAM
EVEN TO A LITTLE DEGREE. MEANWHILE...THE ECMWF AND GFS BOTH SUGGEST
PRECIPITATION WILL BE CONFINED TO THE EASTERN MOST COUNTIES IN
KENTUCKY TODAY. GIVEN THE UNCERTAINTY...HARD TO GO VERY HIGH WITH THE
CHANCE OF RAIN TODAY...ESPECIALLY THE FARTHER WEST YOU GET. BEST
SHORTWAVE ENERGY PROBABLY WILL NOT ARRIVE UNTIL LATE IN THE DAY...SO
HAVE DELAYED POPS INTO THE EVENING HOURS...AND GONE WITH 20 PERCENT
CHANCES IN THE WEST TO 40 PERCENT IN THE FAR EAST. THERE IS A PRETTY
GOOD CHANCE THAT THESE POPS MAY BE TOO HIGH AS WE MAY HAVE A TOUGH
TIME GETTING DECENT COVERAGE. HIGHS TODAY WILL CLIMB INTO THE MID TO
UPPER 80S (AROUND 1 TO 2 DEGREES WARMER THAN YESTERDAY).
GOING TO MAINTAIN SOME SLIGHT POPS TONIGHT AS A WEAK BOUNDARY
ASSOCIATED WITH THE SHORTWAVE CONTINUES TO SAG SOUTHWARD. THIS
BOUNDARY SHOULD EXIT THE SOUTH ON THURSDAY...ALLOWING FOR A RAIN FREE
DAY. AN ISOLATED SHOWER COULD POP UP ALONG THE VIRGINIA OR TENNESSEE
BORDER BY LATE MORNING PRIOR TO THIS FRONT CLEARING THE AREA.
DESPITE THE BOUNDARY SAGGING SOUTH...TEMPERATURES WILL REMAIN JUST AS
WARM WITH HIGHS INTO THE MID TO UPPER 80S.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 307 AM EDT WED AUG 28 2013
THE UPPER LEVEL PATTERN DURING THE PERIOD WILL FEATURE A STRONG
UPPER LEVEL HIGH CENTERED NEAR THE TX/OK PANHANDLES...WITH TROUGHING
ON EITHER SIDE. THE AMPLITUDE OF THE PATTERN WILL FLUCTUATE AS UPPER
LOWS RIDE THROUGH THE WESTERLIES AROUND THE RIDGE. DEAMPLIFICATION
IS EXPECTED EARLY IN THE PERIOD...WITH REAMPLIFICATION TOWARD THE
END. THIS SET-UP PUTS OUR LOCAL AREA IN A GENERAL NW FLOW
ALOFT...FAVORING PERIODIC COLD FRONTAL PASSAGES. ONE FRONT WILL BE
EXITING TO OUR S AND SW AT THE START OF THE PERIOD. SLIGHTLY DRIER
AIR BEHIND THE FRONT SHOULD ALLOW FOR DRY WEATHER THROUGH FRIDAY
NIGHT.
THE FRONT WILL STALL AND WEAKEN AFTER IT PASSES...AND MORE HUMID AIR
WILL BE LOOMING JUST TO OUR S AND W. AS SURFACE HIGH PRESSURE
SLIPS AWAY TO OUR EAST...LOW LEVEL FLOW WILL SEND THIS AIR MASS BACK
INTO OUR AREA DURING THE WEEKEND. MODELS DO SHOW WEAK DISTURBANCES
ALOFT TRAVELING IN THE NW FLOW. COMBINED WITH INCREASING MOISTURE
AND WEAK ISENTROPIC LIFT...THIS MAY VERY WELL ALLOW SCATTERED
SHOWERS AND THUNDERSTORMS TO DEVELOP...AND 30-40 PERCENT POPS WILL
BE USED DURING THE WEEKEND.
AS THE NEXT UPPER LOW HEADS INTO THE GENERALIZED EAST CONUS
TROUGH...PATTERN AMPLIFICATION BEGINS BEFORE THE WEEKEND IS
FINISHED...AND THE REJUVENATED EAST CONUS TROUGH BRINGS ANOTHER COLD
FRONT SOUTHEAST TO OUR AREA. OUR BEST CHANCE AT PRECIP IS WITH
HEATING JUST AHEAD OF THE FRONT ON MONDAY. WILL STICK WITH HIGH
CHANCE POPS AT THIS POINT. THE BEST ESTIMATE FOR FROPA IS MONDAY
NIGHT AND POSSIBLY INTO EARLY TUESDAY. ANY PRECIP SHOULD END NW TO
SE AS DRIER AIR ARRIVES BEHIND THE FRONT. MODELS HAVE NOT BEEN
CONSISTENT CONCERNING THE DEGREE OF COOLING/DRYING BEHIND THIS
FRONT...AND A MODEL BLEND/AVERAGE WILL BE USED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 651 AM EDT WED AUG 28 2013
AN AREA OF 800-1000 FT STRATUS HAS FORMED OVER MUCH OF THE AREA THIS
MORNING ALONG WITH SOME PATCHY FOG. THE FOG/STRATUS MAY LINGER A BIT
LONGER THAN THE PAST FEW MORNINGS AS WE HAVE SOME MID/HIGH CLOUDS
DRIFTING IN FROM THE NORTH WHICH MAY SLOW THE WARMING PROCESS THIS
MORNING. WE SHOULD SEE THINGS RETURN TO MAINLY VFR BY MID TO LATE
MORNING AS TEMPERATURES FINALLY START TO WARM AND WE MIX OUT THE LOW
CLOUDS. A BAND OF ISOLATED SHOWERS MAY WORK INTO THE AREA LATE IN THE
DAY AND COULD AFFECT THE TAF SITES...BUT COVERAGE WILL BE VERY
LIMITED AND WILL NOT INTRODUCE SHOWERS AT THIS TIME. AS A WEAK
FRONTAL BOUNDARY PUSHES SOUTH LATE TONIGHT...ANOTHER ROUND OF VALLEY
FOG MAY BE POSSIBLE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...KAS
LONG TERM...HAL
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1029 AM EDT WED AUG 28 2013
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS...SOME WITH HEAVY RAIN...WILL BE
EXPECTED THROUGH THE AFTERNOON AS AN UPPER LEVEL DISTURBANCE
PUSHES A FRONT SOUTHEASTWARD ACROSS THE REGION. HIGH PRESSURE
BUILDS OVERHEAD FOR THE REST OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AN UPDATE WAS MADE TO ADDRESS THE NEWLY ISSUED FLASH FLOOD WATCH
FOR PRESTON...TUCKER...GARRETT...AND THE WESTMORELAND/FAYETTE
RIDGES THROUGH THIS EVENING. THESE COUNTIES HAVE ALREADY RECEIVED
TWO TO THREE INCHES OF RAIN FROM THE SYSTEM OVERNIGHT...BRINGING
THEM CLOSE TO FLASH FLOOD GUIDANCE ALREADY. WITH THE HRRR AND
OTHER HI RES MODELS SUGGESTING THAT ADDITIONAL SHOWERS AND
THUNDERSTORMS WILL REDEVELOP ALONG THE BOUNDARY PROGGED TO CROSS
BY EARLY AFTERNOON...FELT IT BEST TO ADDRESS THIS WITH A WATCH.
CONTINUED TO CARRY LIKELY POPS FOR THE COUNTIES IN NORTHERN PA
THROUGH THIS AFTERNOON WITH THE SHORTWAVE AND SURFACE LOW MOVING
SLOWLY SOUTHEASTWARD. WITH PWAT VALUES REMAINING CLOSE TO THE 2
INCH RANGE...IT IS NOT OUT OF THE QUESTION THAT THERE COULD
LOCALIZED FLOODING ISSUES. BUT SINCE THESE AREAS WERE NOT PRIMED
WITH RAINFALL FROM YESTERDAY AFTERNOON...OPTED TO LEAVE THEM OUT
OF A WATCH AT THIS TIME.
CONDITIONS SHOULD IMPROVE BY LATE THIS AFTERNOON AS THE WEAK FRONT
DEPARTS SOUTHWARD. WEAK HIGH PRESSURE WILL BUILD OVERHEAD
OVERNIGHT.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
NORTHWEST FLOW ALOFT WILL REMAIN IN PLACE WHILE WEAK SURFACE RIDGE
KEEPS REGION DRY THROUGH THE PERIOD. WHILE DEW POINTS WILL BE
LOWER THAN TODAY...THEY WILL REMAIN ABOVE 60F FOR THE MOST PART
WITH TEMPERATURES RUNNING NEAR 5 DEGREES ABOVE AVERAGE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
SHWR AND TSTM CHCS BEGIN TO INCRS AGAIN FRI NGT AND SAT AS A WRMFNT
APPRCHS FM THE SW. THE FNT SHOULD SHIFT NE ON SUN...HOWEVER SCT
CNVCTN IS STILL PSBL ESP IN THE AFTN. A CDFNT IS PROGGED TO MOVE
THRU ON MON WITH THE BEST CHC FOR SHWRS AND TSTMS. DRY WEA AND HIGH
PRES RTN AFT FROPA. TEMPS EXPD TO BE ABV SEASONAL AVGS UNTIL THE MON
CDFNT PASSAGE BRINGS A LTL BLO AVG TEMPS.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
AMPLE MOISTURE COMBINED WITH AN APPRCHG FRONTAL BNDRY WL CONT TO
BRING MVFR/ISOLD IFR IN SHWRS AND ISOLD TSTMS TO THE AREA THRU THE
MRNG. AS MOISTURE BEGINS TO SHIFT SWD...EXP AN END TO THE MORE
WDSPRD SHWRS GRDLY FM N-S...HOWEVER SCT SHWRS OR A TSTM WL STILL BE
PSBL INTO THE AFTN. SKIES SHOULD CLR OUT THIS EVE HOWEVER OVRNGT
MVFR/IFR FG IS EXPD TO DVLP.
.OUTLOOK.../THURSDAY THROUGH SUNDAY/...
VFR RTNS THU AND FRI WITH BLDG HIGH PRES. RSTRNS IN SHWRS/TSTMS ARE
PSBL SAT AND SUN AS A WRMFNT APRCHS AND MOVES THRU.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR MDZ001.
OH...NONE.
PA...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR PAZ074-076.
WV...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
928 AM MDT WED AUG 28 2013
.UPDATE...
WATER VAPOR LOOP CONTINUES TO SUPPORT A WELL DEFINED INVERTED
TROUGH AXIS PUSHING SLOWLY NORTH ACROSS SOUTHERN NM. LATEST
CIRA BLENDED TPW VALUES ARE HOVERING AT 100-125 PCT OF NORMAL.
SIGNIFICANT CLOUD COVER PUSHING NORTH INTO FAR SOUTHERN AREAS
OF THE CWA IS INHIBITING WARMING BUT THE 15Z LAPS DATA SHOWS A
DESTABILIZING AIRMASS MOVING SLOWLY NORTHWARD FROM THE EL PASO
AREA. LATEST SHORT-TERM MODEL GUIDANCE INCLUDING THE HRRR AND RUC
SHOW WIDESPREAD SHRA/TSRA DEVELOPMENT BY EARLY THIS AFTERNOON
IN THIS AREA SHIFTING NORTH WITH VERY LITTLE ACTIVITY OVER THE
REMAINDER OF NM. RAISED POPS TO LIKELY FOR MORE OF SOUTHERN
LINCOLN AND CATRON COUNTIES AND ADDED MORE OF A CHAVES COUNTY
AS WELL TO MENTION.
GUYER
&&
.PREV DISCUSSION...527 AM MDT WED AUG 28 2013...
.AVIATION...
12Z TAF CYCLE
VFR CONDITIONS TO PERSIST THROUGH THE NEXT 24HRS. LOOK FOR A
GRADUAL LOWERING OF VFR CIGS AT KROW WITH MOISTURE INCREASING FROM
THE SOUTH. ISOLATED SHOWERS MAY COME CLOSE TO KGUP LATE TODAY...
BUT VFR CONDITIONS STILL ANTICIPATED. WINDS WILL GENERALLY BE
LIGHT.
11
.PREV DISCUSSION...316 AM MDT WED AUG 28 2013...
ELY WAVE/UPPER LEVEL CIRCULATION OVER TEXAS PANHANDLE THROWING A
LITTLE KINK IN THE FLOW AROUND UPPER HIGH CENTER OVER MISSOURI.
SOUTHERLY/SELY FLOW ALOFT CONTINUING TO TAP MID AND UPPER LEVEL
SUBTROPICAL MOISTURE EARLY THIS MORNING. THUNDERSTORM ACTIVITY
WILL BE ON THE INCREASE TODAY...ESPECIALLY FOR SOUTHERN AREAS
WHERE PWATS RISE TO NEAR AN INCH. ELSEWHERE...ISOLATED STORMS OVER
THE NORTHERN MOUNTAIN WILL LIKELY GET A LATE START AS SUBSIDENCE
ON THE BACK/WEST SIDE OF UPPER LEVEL WAVE KEEPS DRY UPPER LEVEL
AIR OVER THIS ARE LONGER. MODERATE TO STRONG MID-LEVEL SPEED MAX
ASSOCIATED WITH YET ANOTHER ELY WAVE MOVES THROUGH THE SOUTHERN
ZONES THIS EVENING. THIS FEATURE LIKELY TO KEEP SOME STORMS GOING
OVER THE SW MOUNTAINS OVERNIGHT.
DEEP MOISTURE ON THE RELATIVELY STRONG SOUTH/SELY WINDS AT THE SFC
AND ALOFT SURGES NORTHWARD TONIGHT AND THURSDAY MORNING...WITH A HEALTHY
CROP OF SCT STORMS EXPECTED THURSDAY. ADDITIONALLY...1 INCH PWAT ISOLINE SURGES
NORTHWARD INTO NORTHERN NM THURSDAY MORNING...MAKING SCATTERED
HEAVY RAINERS A VERY GOOD BET. FAVORED AREAS AT THIS POINT LIKELY
THE SOUTHWEST AND SOUTH CENTRAL MOUNTAINS. ISSUED A FLASH FLOOD
WATCH FOR THESE TWO ZONES GIVEN THE SUSCEPTIBILITY OF THE WHITEWATER
BALDY AND LITTLE BEAR BURN SCARS.
UPPER HIGH BUILDS BACK WESTWARD...NOW CENTERED OVER CENTRAL
COLORADO THURSDAY EVENING. SUBTROPICAL MOISTURE PLUME SHIFTS WWD
BUT PLENTY OF RESIDUAL MOISTURE FOR SCT CONVECTION WESTERN AND NRN
MOUNTAINS WITH ISOLD STORMS ELSEWHERE. SUBTROPICAL MOISTURE PLUME WRAPS
AROUND UPPER HIGH CIRCULATION...MOVING BACK INTO NORTHERN AND CENTRAL NM
FOR THE WEEKEND. COMBINATION OF ABOVE AVG PWATS AND ABOVE AVG SFC
TEMPS SHOULD LEAD TO HEALTHY ROUNDS OF AFTERNOON AND EVENING
CONVECTION EACH DAY THIS WEEKEND INTO EARLY NEXT WEEK.
33
.FIRE WEATHER...
ATMOSPHERIC MOISTURE WILL BE ON THE INCREASE TODAY INTO THURSDAY AS
AN EASTERLY WAVE MOVES ACROSS NORTHERN MEXICO AND SOUTHERN AZ/NM.
CHANCES FOR WETTING RAIN AND RELATIVE HUMIDITIES WILL BE TRENDING UP
AS WELL...ESPECIALLY SOUTH AND WEST. GOOD TO EXCELLENT HUMIDITY
RECOVERIES FORECAST TO PERSIST MOST AREAS. THROUGH FRIDAY...LOWEST
HUMIDITIES AND LOWEST CHANCES FOR WETTING RAIN WILL BE EASTERN
PLAINS...CLOSER TO THE SUBSIDENT SIDE OF THE UPPER HIGH CIRCULATION.
CONVECTIVE RECYCLING MODE THROUGH THE WEEKEND WITH THE UPPER HIGH
ANCHORED OVER THE AREA. SOME DRYING/WARMING FORECAST THROUGH THE
WEEKEND WITH NO ADDITIONAL INFLUX OF MOISTURE. DECENT AGREEMENT
BETWEEN THE 00Z GFS AND ECMWF SOLUTIONS OF THE POSITION OF THE UPPER
HIGH THROUGH THE MIDDLE OF NEXT WEEK OVER OUR AREA...WITH ANY
MONSOONAL MOISTURE PLUME MAINLY WEST OF NEW MEXICO OVER ARIZONA.
EASTERN PLAINS LOOK TO HAVE LITTLE TO NO CHANCE FOR WETTING RAINS
THROUGH THE MIDDLE OF NEXT WEEK. NEAR-TERM CONTINUED DRYING OF FINE
FUELS EASTERN PLAINS LOOKS LIKE A GOOD BET.
11
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR THE FOLLOWING ZONES...
NMZ508-526.
&&
$$
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1000 AM EDT WED AUG 28 2013
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE WILL MOVE ACROSS THE REGION FROM THE
NORTHWEST TODAY. A COLD FRONT WILL FOLLOW ON THURSDAY BEFORE WEAK
HIGH PRESSURE RETURNS FOR THE END OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM WEDNESDAY...
CURRENT SATELLITE AND RADAR TRENDS INDICATE THAT THE UPPER LEVEL LOW
MOVING THROUGH VA IS AHEAD OF SCHEDULE AND WILL BE APPROACHING THE
AREA BY 15Z FROM THE NORTH. CURRENT DEVELOPMENT ON THE SOUTHWESTERN
EDGE OF THE DISTURBANCE COUPLED WITH RAP FORECASTED ML CAPE SUGGESTS
THAT THE TRIAD AND THE CENTRAL NORTHERN COUNTIES ALONG THE VA BORDER
WOULD BE THE FIRST INFLUENCED BY THIS SYSTEM. CURRENT RUN OF THE
HRRR SHOWS A SHOWERY SCENARIO WITH SOME EMBEDDED CELLS PUSHING
THROUGH THE CWA THROUGHOUT THE AFTERNOON AND INTO THE EARLY EVENING
HOURS WITH SOME BROKEN LINES TRAILING THE MAIN SHIELD OF
PRECIPITATION LATER THIS AFTERNOON. STILL EXPECTING LESS THAN A
QUARTER OF AN INCH OF QPF WIDESPREAD THIS AFTERNOON WITH LOCALIZED
AREAS RECEIVING MORE IN HEAVIER SHOWERS. RAP SOUNDINGS IN BUFKIT ARE
NOT TERRIBLY IMPRESSIVE AS FAR AS INSTABILITY GOES WITH 500-1000
J/KG OF ELEVATED INSTABILITY ABOVE 800 MB OR SO. BULK SHEAR VALUES
OF 20-30 KTS INDICATE THAT MULTICELLS ARE MOST LIKELY...SUPPORTED BY
THE BROKEN LINES SHOWING UP IN THE CAMS. WET INVERTED V SIGNATURES
DO SUGGEST THAT DAMAGING WINDS MAY BE POSSIBLE...ESPECIALLY IN MORE
ORGANIZED CONVECTION. NOT ANTICIPATING TOO MUCH SEVERE WEATHER BUT A
COUPLE OF WARNINGS ARE POSSIBLE. CURRENT SPC OUTLOOK PUTS US IN IN A
SEE TEXT FOR TODAY WITH MINIMAL MENTION OF SEVERE WEATHER.
FAIRLY DENSE OVERCAST SKIES OVERSPREADING THE CWA FROM THE NORTH
WILL ENDANGER THE ORIGINALLY FORECASTED HIGH TEMPERATURES FOR TODAY
SOUTHWESTERN PORTIONS OF THE CWA COULD BE SPARED A FOR A WHILE
LONGER BUT THE LIKELY SCENARIO FOR HIGHS TODAY WILL BE LOWER TO MID
80S ACROSS MUCH OF THE CWA WITH A FEW ISOLATED UPPER 80S IN THE
SOUTHERN TIER OF COUNTIES. FAIRLY MOIST ATMOSPHERE OVERNIGHT WILL
KEEP LOW TEMPERATURES UP IN THE LOWER 70S ACROSS MUCH OF THE AREA.
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 305 AM WEDNESDAY...
BOTH THE NAM AND THE GFS FORECAST A 700MB SHORTWAVE MOVING THROUGH
CENTRAL NORTH CAROLINA DURING THE DAY ALONG WITH THE COLD FRONT. THE
FRONT SLOWLY SETTLES SOUTH AND SHOULD BE JUST SOUTH OF THE AREA BY
00Z...CONTINUING ITS SLOW PROGRESS SOUTH FROM THERE. THE AIR MASS
REMAINS MOIST ALONG AND BEHIND THE FRONT...BUT BUFR SOUNDINGS FROM
THE NAM AND GFS ARE NOT PARTICULARLY UNSTABLE AND SHOW SOME WARMING
ALOFT AROUND AND JUST ABOVE 700MB. IN A RELATIVE SENSE...THE BETTER
INSTABILITY IS SOUTH OF U.S. 64...AND FOR THIS FORECAST WILL
CONTINUE THE TREND OF A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS
NORTH...CHANCE OVER THE SANDHILLS AND SOUTHERN COASTAL PLAIN WHERE
THE 850MB LIFT IS GREATER THURSDAY DURING THE DAY...DIMINISHING FROM
NORTH-TO-SOUTH LATE IN THE DAY AND IN THE EVENING AS PRECIPITABLE
WATER VALUES FALL FROM NEAR TWO INCHES EARLY THURSDAY TO AT OR BELOW
1.5 INCHES BY 12Z FRIDAY. HIGHER CONFIDENCE IS IN THE DEVELOPMENT OF
AREAS OF CU/SC IN THE MOIST LOW-LEVEL AIR MASS JUST BEHIND THE
FRONT...GIVEN THE DECENT MOISTURE ON THE GFS BUFR SOUNDINGS AND THE
CANADIAN CLOUD COVER MODEL SHOWING NUMEROUS AREAS OF SUCH CLOUDS IN
THE NORTHEAST FLOW BEHIND THE FRONT. LOW-LEVEL RH FORECAST BY THE
NAM AND GFS IS FAIRLY HIGH AS WELL.
OVERNIGHT THURSDAY...THE GFS AND NAM FORECAST THE MID AND UPPER
LEVELS DRYING...WHILE LOW-LEVEL MOISTURE REMAINS WITH DEW POINTS
FROM THE MID 60S TO AROUND 70. THE NAM...WITH ITS LIGHTER AND MORE
VARIABLE WINDS...SUGGESTS THE DEVELOPMENT OF FOG...WHILE THE GFS
WITH A MORE PERSISTENT NORTHEAST WIND SUGGESTS STRATUS. WILL PLAN TO
NOTE PATCHY FOG IN THE GRIDDED AND WORDED FORECAST FOR NOW LATE
THURSDAY NIGHT INTO EARLY FRIDAY. HIGHS THURSDAY IN THE MID 80S
NORTH TO AROUND 90 SOUTH...AGAIN A LITTLE BELOW WHAT THE 1000-850MB
THICKNESSES WOULD SUGGEST FOR HIGHS. OVERNIGHT LOWS THURSDAY NIGHT
66 TO 71.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 305 AM WEDNESDAY...
THE STRONG UPPER LEVEL RIDGE OVER THE CENTRAL US WILL BEGIN TO
WEAKEN AND RETROGRADE WESTWARD ON FRIDAY...WITH NORTHWESTERLY FLOW
ALOFT PERSISTING OVER NC. MEANWHILE...THE WEAK FRONTAL ZONE
CROSSING THE CWA EARLY THURSDAY WILL SINK SOUTH OF THE AREA AND
EVENTUALLY WASH OUT BY FRIDAY. WITH NORTHWESTERLY FLOW ALOFT...THE
LEE TROUGH WILL STRENGTHEN THROUGH THE WEEKEND...AND RETURN FLOW
WILL BRING PW VALUES BACK UP TO AROUND 2 INCHES. UPPER DISTURBANCES
CURRENTLY MOVING AROUND THE UPPER RIDGE WILL INEVITABLY DIVE
SOUTHEAST ACROSS THE APPALACHIANS...BUT ITS DIFFICULT TO FIND ANY
SIGNIFICANT FEATURES IN MODEL GUIDANCE AT THIS POINT. EXPECT A
MOSTLY DRY DAY FRIDAY...WITH AN INCREASING SLIGHT CHANCE TO CHANCE
POP SATURDAY AND SUNDAY. BY MONDAY...MORE SUBSTANTIAL SHORTWAVE IS
EXPECTED TO MOVE ACROSS THE NORTHERN GREAT LAKES AND EASTERN
CANADA..LEADING TO A DEEPER TROUGH OVER THE EASTERN US. AS THE FLOW
ALOFT BECOMES MORE CYCLONIC AND A COLD FRONT APPROACHES FROM THE
NORTHWEST...CONVECTIVE COVERAGE SHOULD INCREASE MONDAY AND TUESDAY.
IN ADDITION...BOTH THE ECMWF INDICATE THAT THE CYCLONIC CIRCULATION
CURRENTLY OVER SOUTHERN FLORIDA WILL DRIFT SLOWLY INTO THE GULF AND
EVENTUALLY BE DRAWN NORTHEASTWARD ACROSS THE SOUTHEAST AND ABSORBED
BY THE LOWER HEIGHTS OVER THE EASTERN US. HOWEVER...THE IMPACTS OF
THIS FEATURE ARE LESS CERTAIN AT THIS TIME. WITH THICKNESSES
HOLDING RELATIVELY STEADY THROUGH THE MONDAY.... HIGH TEMPS OVER THE
WEEKEND WILL REBOUND TO AT OR JUST ABOVE NORMAL IN THE UPPER 80S TO
AROUND 90. LOWS WILL BE IN THE UPPER 60S AND LOWER 70S. SLIGHTLY
COOLER CONDITIONS ARE THEN POSSIBLE BY THE MIDDLE OF NEXT WEEK AS
THE PATTERN BECOMES DOMINATED BY THE STRONGER TROUGH MENTION ABOVE.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 650 AM WEDNESDAY...
BETWEEN SCATTERED TO NUMEROUS AREAS OF MID- AND HIGH-LEVEL CLOUDS
EARLY THIS MORNING THERE WILL BE AREAS OF MVFR CONDITIONS IN FOG.
VERY LOCALLY IFR CONDITIONS WILL OCCUR...BUT THE DOMINANT SUB-VFR
CATEGORY SHOULD BE MVFR DUE TO THE PRESENCE OF THE HIGHER CLOUDS.
VFR CONDITIONS WILL PREVAIL THEN THROUGH THE REST OF THE 12Z VALID
TAF PERIOD OUTSIDE OF ANY SHOWERS OR THUNDERSTORMS. CURRENTLY IT
APPEARS THE BEST POTENTIAL FOR STORMS WILL OCCUR THIS AFTERNOON FROM
THE TRIANGLE NORTHEAST ESPECIALLY TOWARD KRWI...WHERE STORMS MAY
BECOME MORE NUMEROUS DURING THE AFTERNOON. SCATTERED SHOWERS AND
THUNDERSTORMS ARE EXPECTED THIS EVENING. WITH THE RELATIVELY DRY AIR
BELOW MOISTURE ALOFT...ANY STRONG STORM COULD PRODUCE A STRONG WIND
GUST.
BEYOND THE 12Z VALID TAF PERIOD...VFR CONDITIONS ARE EXPECTED
THURSDAY INTO THURSDAY NIGHT...OUTSIDE OF ANY ISOLATED-TO-SCATTERED
SHOWER OR THUNDERSTORM. BOTH THE GFS AND NAM MODEL GUIDANCE ARE
CONFIDENTLY HINTING AT THE POTENTIAL FOR AREAS OF IFR CONDITIONS
LATE THURSDAY NIGHT INTO FRIDAY MORNING BEHIND THE COLD FRONT IN
EITHER LOW CLOUDS OR FOG. LOW CLOUDS AND/OR FOG WILL MIX OUT FRIDAY
LEAVING BEHIND VFR-LEVEL CUMULUS DURING THE DAY. SATURDAY INTO
SUNDAY...VFR CONDITIONS WILL PREVAIL WITH AREAS OF EARLY MORNING FOG
OR LOW CLOUDS POSSIBLE EACH DAY...ALONG WITH ISOLATED-TO-SCATTERED
AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ELLIS
NEAR TERM...ELLIS
SHORT TERM...DJF
LONG TERM...BLS
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
650 AM EDT WED AUG 28 2013
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE WILL MOVE ACROSS THE REGION FROM THE
NORTHWEST THIS AFTERNOON AND THIS EVENING. A COLD FRONT FOLLOWS THE
DISTURBANCE AND PASSES THROUGH NORTH CAROLINA THURSDAY. WEAK HIGH
PRESSURE BUILDS INTO THE REGION BEHIND THE FRONT LATE THURSDAY INTO
FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 650 AM WEDNESDAY...
THE PRIMARY WEATHER CONCERN FOR TODAY INTO TONIGHT WILL BE THE
INFLUENCE OF AN UPPER-LEVEL DISTURBANCE MOVING INTO AND THROUGH
CENTRAL NORTH CAROLINA IN THE NORTHWEST FLOW ALOFT. THE UPPER FLOW
IS BROADLY DIFFLUENT ON WATER VAPOR...AND AS THE DISTURBANCE
APPROACHES THIS AFTERNOON...THE CONSENSUS OF THE GUIDANCE INCREASES
LIFT PARTICULARLY OVER THE NORTH PART OF THE AREA BY 19Z. BUFR
SOUNDINGS FROM BOTH THE NAM AND THE GFS ARE NOT PARTICULARLY
UNSTABLE...AND MLCAPE FORECAST BY BOTH MODELS IS IN THE RANGE OF
ABOUT 1000-1500J/KG. DCAPE IS ONLY MODEST AS WELL...FORECAST TO
ABOUT 500J/KG. 0-3KM SHEAR INCREASES...HOWEVER...TO 25 TO 30KT
COINCIDENT WITH THE APPROACH OF THE MID-LEVEL WAVE AND THE GFS
FORECAST OF A WEAK 500MB JETLET TOWARD THE NORTHEAST PIEDMONT AROUND
35KT. IN ADDITION...THE HIGHEST QPF FORECAST BY THE GFS AND THE NAM
TODAY...ALONG WITH THE CONVECTIVE-ALLOWING MODELS FROM WPC AND SPC...
SUGGEST HIGHEST CHANCES AND THE POTENTIAL FOR A PERIOD OF NUMEROUS
SHOWERS AND THUNDERSTORMS OVER THE NORTHEAST PIEDMONT AND NORTHERN
COASTAL PLAIN THIS AFTERNOON FROM ABOUT 20Z TO 00Z. GIVEN THE
RELATIVELY DRY AIR BELOW THE MID-LEVELS ON BUFR SOUNDINGS...ANY
STRONG STORM COULD PRODUCE A STRONG-TO-SEVERE WIND GUST. WILL NOTE A
MENTION OF THIS IN THE HWO FOR THIS AFTERNOON INTO THIS EVENING...
WITH MORE OF A FOCUS NORTHEAST. SOUTH OF U.S. 64 AND ESPECIALLY
ACROSS THE SANDHILLS AND FAR SOUTHERN COASTAL PLAIN...GIVEN THE
GREATER STABILITY AND LACK OF A MAIN SOURCE OF LIFT FOR MUCH OF THE
DAY...PRECIPITATION THERE IS EXPECTED TO BE MORE ISOLATED. DURING
THE EVENING AND OVERNIGHT HOURS...MESOSCALE INFLUENCES DUE TO
OUTFLOW...ALONG WITH A MAXIMUM OF MOISTURE WITH PRECIPITABLE
WATER VALUES AT OR JUST ABOVE TWO INCHES AND DECENT DIFFLUENCE ALOFT
AS FORECAST BY THE GFS...ANTICIPATE OVERALL SCATTERED SHOWERS AND
THUNDERSTORMS BECOMING ISOLATED OVERNIGHT AS BUFR SOUNDINGS
GRADUALLY BECOME MORE STABLE. HIGHS TODAY ARE A LITTLE TRICKY GIVEN
THE MOISTURE UPSTREAM...BUT THINK THERE WILL BE ENOUGH PERIODS OF
SUN THAT HIGHS CLOSE TO THE MOS GUIDANCE SHOULD BE REALIZED IN MOST
LOCATIONS. THE CONSENSUS OF BIAS-CORRECTED GUIDANCE IS ABOUT A
DEGREE OR TWO BELOW MOS...AND WILL LEAN TOWARD A BLEND.
ON THE OTHER HAND...TAKING A LOOK AT THE LATEST RADAR AND SATELLITE
TRENDS...ALONG WITH SOME OF THE HRRR WRF GUIDANCE...CLOUDS AND
PRECIPITATION FROM THE UPSTREAM WAVE MAY MOVE IN FASTER THAN EARLIER
GUIDANCE SHOWED AND WAS ANTICIPATED. FOR THE EARLY MORNING
UPDATE...LOWERED MAXES ABOUT A DEGREE OR SO NORTH OF U.S. 64 AND
NOTED A CHANCE OF A SHOWER EARLIER ESPECIALLY TOWARD THE VIRGINIA
BORDER. CLOUDS COULD ALSO HAMPER AVAILABLE INSTABILITY. CONFIDENCE
HAS BEEN REDUCED A LITTLE DUE TO THE PROGRESSION OF THE WAVE.
OVERNIGHT LOWS TONIGHT MOSTLY IN THE LOWER 70S.
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 305 AM WEDNESDAY...
BOTH THE NAM AND THE GFS FORECAST A 700MB SHORTWAVE MOVING THROUGH
CENTRAL NORTH CAROLINA DURING THE DAY ALONG WITH THE COLD FRONT. THE
FRONT SLOWLY SETTLES SOUTH AND SHOULD BE JUST SOUTH OF THE AREA BY
00Z...CONTINUING ITS SLOW PROGRESS SOUTH FROM THERE. THE AIR MASS
REMAINS MOIST ALONG AND BEHIND THE FRONT...BUT BUFR SOUNDINGS FROM
THE NAM AND GFS ARE NOT PARTICULARLY UNSTABLE AND SHOW SOME WARMING
ALOFT AROUND AND JUST ABOVE 700MB. IN A RELATIVE SENSE...THE BETTER
INSTABILITY IS SOUTH OF U.S. 64...AND FOR THIS FORECAST WILL
CONTINUE THE TREND OF A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS
NORTH...CHANCE OVER THE SANDHILLS AND SOUTHERN COASTAL PLAIN WHERE
THE 850MB LIFT IS GREATER THURSDAY DURING THE DAY...DIMINISHING FROM
NORTH-TO-SOUTH LATE IN THE DAY AND IN THE EVENING AS PRECIPITABLE
WATER VALUES FALL FROM NEAR TWO INCHES EARLY THURSDAY TO AT OR BELOW
1.5 INCHES BY 12Z FRIDAY. HIGHER CONFIDENCE IS IN THE DEVELOPMENT OF
AREAS OF CU/SC IN THE MOIST LOW-LEVEL AIR MASS JUST BEHIND THE
FRONT...GIVEN THE DECENT MOISTURE ON THE GFS BUFR SOUNDINGS AND THE
CANADIAN CLOUD COVER MODEL SHOWING NUMEROUS AREAS OF SUCH CLOUDS IN
THE NORTHEAST FLOW BEHIND THE FRONT. LOW-LEVEL RH FORECAST BY THE
NAM AND GFS IS FAIRLY HIGH AS WELL.
OVERNIGHT THURSDAY...THE GFS AND NAM FORECAST THE MID AND UPPER
LEVELS DRYING...WHILE LOW-LEVEL MOISTURE REMAINS WITH DEW POINTS
FROM THE MID 60S TO AROUND 70. THE NAM...WITH ITS LIGHTER AND MORE
VARIABLE WINDS...SUGGESTS THE DEVELOPMENT OF FOG...WHILE THE GFS
WITH A MORE PERSISTENT NORTHEAST WIND SUGGESTS STRATUS. WILL PLAN TO
NOTE PATCHY FOG IN THE GRIDDED AND WORDED FORECAST FOR NOW LATE
THURSDAY NIGHT INTO EARLY FRIDAY. HIGHS THURSDAY IN THE MID 80S
NORTH TO AROUND 90 SOUTH...AGAIN A LITTLE BELOW WHAT THE 1000-850MB
THICKNESSES WOULD SUGGEST FOR HIGHS. OVERNIGHT LOWS THURSDAY NIGHT
66 TO 71.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 305 AM WEDNESDAY...
THE STRONG UPPER LEVEL RIDGE OVER THE CENTRAL US WILL BEGIN TO
WEAKEN AND RETROGRADE WESTWARD ON FRIDAY...WITH NORTHWESTERLY FLOW
ALOFT PERSISTING OVER NC. MEANWHILE...THE WEAK FRONTAL ZONE
CROSSING THE CWA EARLY THURSDAY WILL SINK SOUTH OF THE AREA AND
EVENTUALLY WASH OUT BY FRIDAY. WITH NORTHWESTERLY FLOW ALOFT...THE
LEE TROUGH WILL STRENGTHEN THROUGH THE WEEKEND...AND RETURN FLOW
WILL BRING PW VALUES BACK UP TO AROUND 2 INCHES. UPPER DISTURBANCES
CURRENTLY MOVING AROUND THE UPPER RIDGE WILL INEVITABLY DIVE
SOUTHEAST ACROSS THE APPALACHIANS...BUT ITS DIFFICULT TO FIND ANY
SIGNIFICANT FEATURES IN MODEL GUIDANCE AT THIS POINT. EXPECT A
MOSTLY DRY DAY FRIDAY...WITH AN INCREASING SLIGHT CHANCE TO CHANCE
POP SATURDAY AND SUNDAY. BY MONDAY...MORE SUBSTANTIAL SHORTWAVE IS
EXPECTED TO MOVE ACROSS THE NORTHERN GREAT LAKES AND EASTERN
CANADA..LEADING TO A DEEPER TROUGH OVER THE EASTERN US. AS THE FLOW
ALOFT BECOMES MORE CYCLONIC AND A COLD FRONT APPROACHES FROM THE
NORTHWEST...CONVECTIVE COVERAGE SHOULD INCREASE MONDAY AND TUESDAY.
IN ADDITION...BOTH THE ECMWF INDICATE THAT THE CYCLONIC CIRCULATION
CURRENTLY OVER SOUTHERN FLORIDA WILL DRIFT SLOWLY INTO THE GULF AND
EVENTUALLY BE DRAWN NORTHEASTWARD ACROSS THE SOUTHEAST AND ABSORBED
BY THE LOWER HEIGHTS OVER THE EASTERN US. HOWEVER...THE IMPACTS OF
THIS FEATURE ARE LESS CERTAIN AT THIS TIME. WITH THICKNESSES
HOLDING RELATIVELY STEADY THROUGH THE MONDAY.... HIGH TEMPS OVER THE
WEEKEND WILL REBOUND TO AT OR JUST ABOVE NORMAL IN THE UPPER 80S TO
AROUND 90. LOWS WILL BE IN THE UPPER 60S AND LOWER 70S. SLIGHTLY
COOLER CONDITIONS ARE THEN POSSIBLE BY THE MIDDLE OF NEXT WEEK AS
THE PATTERN BECOMES DOMINATED BY THE STRONGER TROUGH MENTION ABOVE.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 650 AM WEDNESDAY...
BETWEEN SCATTERED TO NUMEROUS AREAS OF MID- AND HIGH-LEVEL CLOUDS
EARLY THIS MORNING THERE WILL BE AREAS OF MVFR CONDITIONS IN FOG.
VERY LOCALLY IFR CONDITIONS WILL OCCUR...BUT THE DOMINANT SUB-VFR
CATEGORY SHOULD BE MVFR DUE TO THE PRESENCE OF THE HIGHER CLOUDS.
VFR CONDITIONS WILL PREVAIL THEN THROUGH THE REST OF THE 12Z VALID
TAF PERIOD OUTSIDE OF ANY SHOWERS OR THUNDERSTORMS. CURRENTLY IT
APPEARS THE BEST POTENTIAL FOR STORMS WILL OCCUR THIS AFTERNOON FROM
THE TRIANGLE NORTHEAST ESPECIALLY TOWARD KRWI...WHERE STORMS MAY
BECOME MORE NUMEROUS DURING THE AFTERNOON. SCATTERED SHOWERS AND
THUNDERSTORMS ARE EXPECTED THIS EVENING. WITH THE RELATIVELY DRY AIR
BELOW MOISTURE ALOFT...ANY STRONG STORM COULD PRODUCE A STRONG WIND
GUST.
BEYOND THE 12Z VALID TAF PERIOD...VFR CONDITIONS ARE EXPECTED
THURSDAY INTO THURSDAY NIGHT...OUTSIDE OF ANY ISOLATED-TO-SCATTERED
SHOWER OR THUNDERSTORM. BOTH THE GFS AND NAM MODEL GUIDANCE ARE
CONFIDENTLY HINTING AT THE POTENTIAL FOR AREAS OF IFR CONDITIONS
LATE THURSDAY NIGHT INTO FRIDAY MORNING BEHIND THE COLD FRONT IN
EITHER LOW CLOUDS OR FOG. LOW CLOUDS AND/OR FOG WILL MIX OUT FRIDAY
LEAVING BEHIND VFR-LEVEL CUMULUS DURING THE DAY. SATURDAY INTO
SUNDAY...VFR CONDITIONS WILL PREVAIL WITH AREAS OF EARLY MORNING FOG
OR LOW CLOUDS POSSIBLE EACH DAY...ALONG WITH ISOLATED-TO-SCATTERED
AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...DJF
SHORT TERM...DJF
LONG TERM...BLS
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
940 AM EDT WED AUG 28 2013
.SYNOPSIS...
A COLD FRONT WILL SLIDE FROM THE SOUTHERN GREAT LAKES THIS MORNING
SOUTH TO THE NORTH CAROLINA/VIRGINIA BORDER BY THURSDAY MORNING. WEAK
HIGH PRESSURE ARRIVES AFTER THURSDAY. WARM FRONT HEADS NORTH
ACROSS OUR AREA BY SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 935 AM EDT WEDNESDAY...
A SHORT-WAVE TROUGH OVER THE GREAT LAKES WILL TRAVEL SOUTHEAST TO
OFF THE MID ATLANTIC COAST BY TONIGHT. THIS MORNING 8AM/12Z RNK
SOUNDING DISPLAYED THE JUICY AIRMASS WITH PWATS AROUND 1.5 INCHES
WITH A WEST TO NORTHWEST FLOW. MODIFIED POPS FOR THE NEXT COUPLE
COUPLE OF HOURS TOWARDS THE HRRR WHICH LINED UP FAIRLY WELL WITH
WSR-88D TRENDS. CONTINUED THE HIGHER POPS FOR THIS AFTERNOON IN
THE NORTH AND EAST AS SUPPORT BY ECMWF...GFS AND NAM. SPC HAS
REMOVE THE SEE TEXT OF SEVERE WEATHER FROM OUR AREA WITH THE
EXPECTATION THAT WIDESPREAD CLOUDS WOULD INHIBIT AIRMASS
DESTABILIZATION. QUESTION OF HOW MUCH SUNSHINE WILL DETERMINE IF
WE HAVE ISOLATED SEVERE STORMS THIS AFTERNOON WITH THE THREAT FOR
GUSTY WINDS AND HEAVY RAINS. MORE LATER THIS AFTERNOON...
AS OF 730 AM EDT WEDNESDAY...
BUMPED UP POPS OVER THE NW CWA AS CONVECTION SLIDES SE INTO THE
SRN SHENANDOAH VALLEY. THIS WILL PROGRESS SE INTO THE PIEDMONT
THROUGH THE MORNING WITH EXPECTATIONS OF WEAKENING SOMEWHAT AS IT
CROSSES THE BLUE RIDGE. GIVEN EXTENT OF CLOUD COVER AND SHOWERS
THINKING IS THAT HIGHS TODAY WILL BE A COUPLE MORE DEGREES COOLER
AND LOWER THEM ESPECIALLY FROM THE BLUE RIDGE EAST. THIS MORNINGS
CONVECTION WILL LEAVE BEHIND SOME BOUNDARIES AND NEXT UPSTREAM
WAVE WILL INTERACT WITH THIS TO GENERATE MORE SHOWERS AND STORMS
THIS AFTERNOON. QUESTION REMAINS ON HOW MUCH SUN MAY PEAK
OUT...ESPECIALLY OUT EAST WHERE CLOUDS LOOK TO HANG LONGER. SVR
THREAT STILL APPEARS ISOLATED AND MAY BE MORE OVER THE SOUTHWEST
WHERE BETTER CHANCE OF SEEING SUN OCCURS...ALTHOUGH WILL BE
FURTHER AWAY FROM UPPER FORCING.
PREVIOUS DISCUSSION AT 330 AM...
JUICY AIRMASS WILL BE IN PLACE TODAY AS THETA-E RIDGE AND SFC FRONT
NORTH OF US SHIFTS ESE LATE TONIGHT. MODELS ARE TRACKING A PIECE OF
ENERGY ASSOCIATED WITH CONVECTION OVER THE EASTERN GREAT LAKES/WRN
PA THIS MORNING AND TAKING IT SOUTHEAST ACROSS EASTERN WV/VA INTO NE
NC LATER THIS MORNING INTO THIS EVENING. AT THIS TIME...THE 12Z
ECMWF AS WELL AS THE 00Z LOCAL WRF WERE HANDLING THE LOCATIONS OF
CONVECTION EARLY THOUGH THE ECMWF SEEMS OVERDONE. SEEING THE LATEST
00Z ECMWF THAT JUST ARRIVED KEEPS IT SIMILAR TO THE 12Z BUT A LITTLE
SLOWER IN TIMING. GIVEN WHERE THE THETA-E RIDGE LINES UP AND
MOVEMENT OF THE UPPER WAVE...THINK OUR NRN AND ERN CWA APPEARS TO BE
MORE IN LINE OVERALL TO RECEIVE MORE QPF....THEREFORE HIGHER POPS BY
THIS AFTERNOON. ROUGHLY EAST/NORTHEAST OF A LINE FROM LWB-ROA-DAN.
THE STORM PREDICTION CENTER HIGHLIGHTS US IN A SEE TEXT WITH 5
PERCENT THREAT OF SVR WINDS. MODEST WIND FIELDS AND HIGHER PWATS
FAVOR STRONG WIND GUSTS AND KEPT THE WORDING OF GUSTY WINDS FROM
PREVIOUS FORECAST FOR THE AFTERNOON PERIOD CWA WIDE. LIMITING FACTOR
EXPECTED TO BE CLOUD COVER. THE 00Z CMC/NAM SHOWING THE SOUTHWEST
FROM BLACKSBURG TO MARION SOUTH TO BOONE/WILKESBORO SEEING MORE SUN.
THIS MAY BE THE AREA TO WATCH FOR ISOLATED SVR...WHILE CLUSTER OF
STORMS WITH SHORTWAVE/MCS WILL IMPACT THE NORTHEAST CWA WITH HEAVIER
RAINS...AND LOCALLY SVR WINDS. WILL HIGHLIGHT THREAT OF HEAVY RAIN
AND ISOLATED SVR IN THE HWO.
DURING THE EVENING THE FOCUS SHIFTS MORE OVER THE PIEDMONT AND
COASTAL AREAS OF VA/NC AND WITH FRONT ENTERING THE CWA...MODELS KEEP
THE CONVERGENCE AND SHOWERS LINED UP ACROSS THE EAST/SOUTH EARLY
WITH LESS CHANCE IN THE NORTH AND SOUTHWEST...WITH SOME UPSLOPE
ENHANCEMENT IN SE WV. WITH THE NEW ECMWF SLOWING THINGS DOWN SOME
KEPT HIGHER POPS IN THE EVENING THEN START TO LOWER TO SLIGHT
CHANCE/LOW CHANCE OVERNIGHT.
FOR HIGHS TODAY...THREAT OF MORE CLOUDS AND CONVECTION IN THE
NORTHERN CWA SWAYS ME TO GO A COUPLE/3 DEGREES COOLER THAN MOS WITH
UPPER 70S HSP/LWB TO MID 80S LYH/FVX. OF COURSE IF ANY SUN WERE TO
STAY OUT FOR AN HOUR AND GIVEN DOWNSLOPE AHEAD OF FRONT...90 COULD
BE POSSIBLE AT LYH/FVX...BUT MODEL CLOUD FIELDS LEAD ME TO BELIEVE
COOLER IS MORE LIKELY. NOW THE FURTHER SOUTHWEST WE GO THE WARMER IT
WILL BE AS SUN WILL BE MIXED IN AT TIMES. STILL BEING THE POTENTIAL
FOR SOME CLOUDS FROM UPSTREAM CONVECTION SETTLED CLOSE TO MOS
GUIDANCE WITH LOWER TO MID 80S SOUTHWEST VA MOUNTAINS/VALLEYS TO MID
TO NEAR 90 ROANOKE/DANVILLE/NW NC PIEDMONT/FOOTHILLS.
LITTLE CHANGE IN AIRMASS TONIGHT SO LOWS WILL STAY WARM FROM THE MID
60S ACROSS THE ALLEGHANY HIGHLANDS/GREENBRIER VALLEY TO UPPER 60S TO
LOWER 70S ELSEWHERE.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
AS OF 345 AM EDT WEDNESDAY...
ALTHOUGH WEAK BOUNDARY WILL BE JUST TO OUR SOUTH THURSDAY...GOOD
SURFACE WIND CONVERGENCE ALONG THE SOUTHERN BLUE RIDGE SHOULD FORCE
SHOWERS AND THUNDERSTORMS FOR THE AFTERNOON. HOWEVER...MOISTURE
LOOKS RATHER SCANT IN THE MID LEVELS...SO THIS MAY BE A LIMITING
FACTOR. H85 TEMPS WILL ONLY BE A FEW DEGREES COOLER BEHIND THIS SO
CALLED FRONT WITH SURFACE DEWPOINTS STAYING IN THE SOUPY MID 60S.
LESS MOISTURE ALOFT IS WHAT REALLY KNOCKS DOWN THE PWATS IN
COMPARISON TO WEDNESDAY. WEAK HIGH PRESSURE WILL STRETCH FROM THE
MID ATLANTIC AND OFF THE COAST ON FRIDAY. WITH MORE OF AN EASTERLY
COMPONENT...INSTABILITY IS REDUCED...TEMPS ARE COOLER...WITH THIS
BEING THE DRIEST DAY OF THE SHORT TERM. HIGHEST POPS WILL BE PLACED
OVER NW NC. AS THE SURFACE HIGH MOVES OF THE COAST SATURDAY...WINDS
VEER TO MORE OF A SOUTHERLY DIRECTION. THIS ALLOWS MORE MOISTURE TO
RETURN BACK NORTH AND COMBINE WITH A DEEPENING TROUGH ACROSS THE
GREAT LAKES AND OHIO VALLEY TO PRODUCE MORE WIDESPREAD STORMS THAN
FRIDAY...WITH THE MOST ALONG THE BLUE RIDGE. WITH PWATS ELEVATED
ONCE AGAIN AND WEAK FLOW...THERE MAY BE THE POTENTIAL FOR SOME
BACKBUILDING HEAVY RAINERS AND WATER PROBLEMS. BASED ON THE CLOUDS
AND POTENTIAL FOR STORMS...DID STAY BELOW GUIDANCE THURSDAY AND
SATURDAY FOR HIGHS.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 115 PM EDT TUESDAY...
DIFFERENT MODEL GUIDANCE DURING THIS PORTION OF THE FORECAST PACKAGE
VARIES OF THE SPECIFICS...BUT IS FAIRLY CONSISTENT ON THE
GENERALITIES. GENERALLY SPEAKING...THE NORTHEAST U.S. IS EXPECTED TO
HAVE SOME DEGREE OF TROUGHINESS OVER IT DURING THIS PORTION OF THE
FORECAST...WITH NORTHWEST FLOW ALOFT OVER OUR REGION. CLOSER TO THE
SURFACE...HIGH PRESSURE WILL TAKE UP RESIDENCE ALONG THE EAST
COAST...AND PREVAILING FLOW AROUND IT WILL HELP DEVELOP FLOW FROM
THE SOUTH THAT WILL DIRECT MOISTURE INTO OUR REGION. DURING THE
MONDAY INTO TUESDAY TIME FRAME...A NORTHERN STREAM TROUGH WILL HELP
DEEPEN...AND THEN GRADUALLY EJECT THE EAST COAST TROUGH INTO THE
WESTERN ATLANTIC...AND UPPER LEVEL RIDGING WILL START NOSING INTO
THE AREA FROM THE MID-WEST.
THE ABOVE POINTS TOWARD THE FOLLOWING SCENARIO. MAINLY AFTERNOON AND
EARLY EVENING SCATTERED SHOWERS AND STORMS ARE EXPECTED SUNDAY
TRIGGERED PRIMARILY BE DAYTIME HEATING. HOWEVER...AND THIS IS
WHERE THE SPECIFICS GET TRICKY...UPSTREAM SHORTWAVE TROUGHS MAY
RIDE SOUTHEAST WITHIN THE NORTHWEST FLOW ALOFT AND ADD AN
INCREASED ELEMENT OF UPPER LEVEL DYNAMICS TO THE FORECAST PICTURE
AND THUS BETTER COVERAGE. SIMILARITY...THIS SAME FLOW MAY HELP
ADVECT AN UPSTREAM THUNDERSTORM COMPLEX INTO THE REGION...AND THIS
TOO WOULD ALLOW FOR BETTER COVERAGE OF SHOWERS AND
STORMS...ESPECIALLY ACROSS THE WESTERN PORTION OF THE AREA.
PINPOINTING THESE FEATURES IS WHERE MODEL GUIDANCE VARIES TOO
GREATLY TO TRY TO INCORPORATE EITHER OF THESE SCENARIOS INTO THE
FORECAST AT THIS TIME.
MONDAY INTO TUESDAY...GUIDANCE ALSO VARIES AS TO THE TIMING AND
TRACK OF THE NORTHERN STREAM SYSTEM AND THUS THE IMPACT AND TIMING
OF ITS ASSOCIATED SURFACE COLD FRONT. WE WILL OFFER A SOLUTION
COMPARABLE TO WHAT IS PUT FORTH BY WPC WITH MONDAY AFTERNOON AND
EVENING LOOKING THE MOST PROMISING CURRENTLY. WOULD NOT BE SURPRISED
AS WE DRAW NEARER TO THIS TIME FRAME THAT THE FRONT ENDS UP ARRIVING
MONDAY NIGHT INTO TUESDAY MORNING...OR LATER.
TEMPERATURES THROUGH THIS TIME FRAME SHOULD SLOWLY INCREASE THROUGH
MONDAY AHEAD OF THE COLD FRONT...AND THEN BE COOLER AND LESS HUMID
ON TUESDAY WITH OUR CURRENT FORECAST TIMING OF THE COLD FRONT.
&&
.AVIATION /13Z WEDNESDAY THROUGH SUNDAY/...
AS OF 740 AM EDT WEDNESDAY...
SHOWERS/SOME THUNDER EXITING THE LWB AREA AND MAY SEE SHOWERS
AFFECT ROA/LYH THIS MORNING BUT TREND IS FOR WEAKENING. STILL
LOOKS LIKE ANY LOWER CLOUDS/RESIDUAL FOG THIS MORNING WILL MIXT
OUT TO VFR BY 15Z WITH SOME HAZE LINGERING.
NEXT UPSTREAM WAVE WILL BE EXPECTED TO ARRIVE THIS AFTERNOON AND
SHOULD GENERATE A GOOD COVERAGE OF SHOWERS AND SOME TSRA EAST OF
THE LWB/ROA/DAN LINE. HERE HAVE STILL KEPT IT VCTS WITH
PREDOMINANT SHRA. BEST CHANCE FOR THUNDER HITTING A TERMINAL
APPEARS TO BE LYH...BUT CLOUD COVER MAY LIMIT CONVECTION SOME.
FURTHER WEST...THERE WILL REMAIN SOME CHANCE OF SHOWERS/STORMS
BUT LOOKS LIKE BLF WILL BE ON THE EDGE. BY THIS EVENING THE MODELS
TRACK THE PRECIP EAST AND OFFSHORE OVERNIGHT. CLOUDS MAY LINGER
OVERNIGHT IN THE EAST BUT ENOUGH CLEARING IN THE WEST COULD LEAD
TO SOME FOG ISSUES AT LWB/BLF AND BCB...MEANING IFR OR WORSE.
SPOTTY SHOWERS AND THUNDERSTORMS WILL REMAIN IN THE FORECAST FOR
THURSDAY AS WEAK DISTURBANCES RIDE ACROSS THE AREA FROM THE GREAT
LAKES OVERTOP NORTHEASTERLY FLOW NEAR THE SURFACE AS HIGH
PRESSURE BUILDS IN. EXPECT A RETURN TO OVERALL VFR CONDITIONS UNDER
HIGH PRESSURE...WITH ONLY ISOLATED SHOWERS AT BEST FRIDAY AND
SATURDAY. OTHERWISE SOME PATCHY FOG LIKELY DURING THE OVERNIGHTS
INTO SATURDAY...WITH LATE NIGHT/EARLY MORNING MVFR/IFR CONDITIONS
POSSIBLE ESPECIALLY AT THE VALLEY LOCATIONS.
&&
.EQUIPMENT...
AS OF 400 AM EDT WEDNESDAY...
THE TEMPERATURE/DEWPOINT AT THE ROANOKE ASOS (ROA) WILL BE
AUGMENTED BY OBSERVERS FROM AN AUXILIARY UNIT UNTIL FURTHER
NOTICE. TIME OF RESTORATION OF THE PRIMARY EQUIPMENT WILL BE
LATER TODAY AT THE EARLIEST.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WP
NEAR TERM...KK/WP
SHORT TERM...KM
LONG TERM...DS
AVIATION...NF/WP
EQUIPMENT...AMS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
910 AM CDT WED AUG 28 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM CDT WED AUG 28 2013
..CURRENTLY AS OF 08Z..
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED DEEP TROUGHING
JUST OFF THE U.S. WEST COAST WHILE STRONG SUBTROPICAL RIDGING
CONTINUES TO DOMINATE THE CENTRAL PLAINS. A WEAK RIDGE AXIS EXTENDED
FROM THE SUBTROPICAL RIDGE NORTH INTO THE DAKOTAS. MONSOONAL
MOISTURE AND SHORTWAVES CONTINUE TO ROTATE AROUND THE SUBTROPICAL
RIDGE...FROM ARIZONA INTO THE DAKOTAS AND SOUTHEAST THROUGH THE
FORECAST AREA. REGARDING THE MOISTURE...RAP PRECIPITABLE WATER
ANALYSIS SHOWED VALUES OF 1.5-2 INCHES EXTENDING FROM THE DAKOTAS
SOUTHEASTWARD THROUGH MUCH OF THE FORECAST AREA. EARLY THIS MORNING
ALL MONSOONAL SHORTWAVES WERE EITHER TO THE EAST OR WEST OF THE
FORECAST AREA...RESULTING IN DRY CONDITIONS. AT THE SURFACE A WEAK
COLD FRONT WAS SLOWLY DROPPING SOUTH THROUGH THE FORECAST AREA...NOW
STRETCHED ACROSS NORTHERN IOWA AND FAR SOUTHERN WI. THE FRONT HAS
HAD A HARD TIME SCOURING OUT THE SURFACE MOISTURE WITH DEWPONTS
GENERALLY IN THE LOW 70S ACROSS THE AREA. THE COOLING WITH THE FRONT
HAS BEEN SHALLOW...EVIDENCED ON THE 00Z GRB SOUNDING WITH 925MB
TEMPS OF 22C COMPARED TO 29C AT DVN. SURFACE TEMPERATURES HAVE
FALLEN OFF INTO THE LOW TO MID 70S NORTH OF THE FRONT...AND MID TO
UPPER 70S TO THE SOUTH. THE COOLING INTERACTING WITH THE LINGERING
MOISTURE HAS CAUSED BOTH MIST AND LOW STRATUS TO FORM. VISIBILITIES
ARE LOWEST OVER NORTH CENTRAL WI DUE TO RECENT RAINS. 11-3.9 UM
IMAGERY SHOWED THE BULK OF THE STRATUS ACROSS CENTRAL AND EASTERN
WI.
..HAZARDS..
1. HEAT. NORTH OF I-90...HEAT INDICES ARE FORECAST BETWEEN
90-95...THEREFORE FEEL CONFIDENT NO ADDITIONAL HEAT ADVISORY IS
NEEDED. SOUTH OF I-90 HEAT INDICES ARE EXPECTED TO TOP OUT AROUND
95 TO AT MOST 100. GIVEN THAT THESE ARE BELOW ADVISORY CRITERIA
AND 5 TO 10 DEGREES LOWER THAN THE PAST FEW DAYS...HAVE DECLINED
TO ISSUE A HEAT ADVISORY HERE AS WELL.
2. DENSE FOG ACROSS TAYLOR AND CLARK COUNTIES...WHICH SHOULD
DISSIPATE BETWEEN 9-10 AM.
..SYNOPTIC OVERVIEW..
VERY LITTLE CHANGE IS FORECAST BY MODELS IN THE UPPER AIR PATTERN
DURING THE NEXT 24 HOURS. IF ANYTHING...THE WEAK RIDGE AXIS OVER THE
DAKOTAS GETS FLATTENED OUT AND PUSHED EAST...IN RESPONSE TO A
STRONGER MONSOONAL SHORTWAVE LIFTING INTO NORTH DAKOTA BY 12Z
THURSDAY. AT THE SURFACE...THE WEAK COLD FRONT OVER THE SOUTHERN
PORTION OF THE FORECAST AREA LOOKS TO CONTINUE TO SLOWLY DRIFT
SOUTH...PROGGED TO BISECT IOWA NORTHWEST TO SOUTHEAST BY 00Z. IN
ITS WAKE...HIGH PRESSURE BUILDS IN OVER WISCONSIN. THE FRONT MAY
START TO LIFT BACK TOWARDS THE AREA LATE TONIGHT IN RESPONSE TO WARM
ADVECTION AHEAD OF THE SHORTWAVE MOVING INTO NORTH DAKOTA.
..DETAILS..
SOLAR HEATING WILL HELP TO GRADUALLY IMPROVE VISIBILITIES AND MIX
OUT THE LOW STRATUS AIMING AT SOUTHWEST WI THIS MORNING. BY 18Z ALL
FOG AND STRATUS SHOULD BE GONE. OTHERWISE...DRY ADVECTION IN THE LOW
TO MID LEVELS OF THE ATMOSPHERE ACCOMPANYING THE SURFACE HIGH...
COMBINED WITH CAPPING BY A WARM LAYER AT 750MB...WILL HELP TO KEEP
CONDITIONS DRY TODAY. THE 28.00Z GFS DOES TRY TO CONVECT ACROSS
NORTHEAST IOWA NEAR THE FRONT THIS AFTERNOON...BUT IS THE ONLY MODEL
TO DO SO. HAVE KEPT THE FORECAST DRY DUE TO LIMITED CONVERGENCE ON
THE FRONT AND THE CAPPING POTENTIAL...ALONG WITH ALL OTHER MODELS
SUGGESTING DRY CONDITIONS ON THE FRONT. TEMPERATURES TODAY WILL BE
ABOUT 5 DEGREES COOLER WITH 925MB READINGS DOWN TO 24-26C VERSUS THE
28-30C THAT OCCURRED YESTERDAY. SURFACE DEWPOINTS...ON THE OTHER
HAND...ARE STILL GOING TO BE STUCK IN THE LOW TO PERHAPS MID 70S
SOUTH OF I-90. THUS HEAT INDICES IN THIS AREA OF 95 TO AT MOST 100
ARE EXPECTED. TO THE NORTH...DEWPOINTS SHOULD MIX/FALL INTO THE
60S...KEEPING HEAT INDICES MORE IN THE 90-95 RANGE.
FOR TONIGHT...GOOD MODEL AGREEMENT EXISTS ON THE WARM ADVECTION
SCENARIO. THE BIGGEST ISSUES ARE IF AND WHEN CONVECTION CAN FIRE
FROM THE WARM ADVECTION. HERE AGAIN...THE 28.00Z GFS IS QUICKEST AND
MOST EXPANSIVE...SUGGESTING CONVECTION WEST OF THE MS RIVER ALL
NIGHT. ALL OTHER GUIDANCE WAITS UNTIL AFTER MIDNIGHT...AND IN THE
CASE OF THE 28.00Z REGIONAL CANADIAN AS WELL AS THE 28.00Z NAM...
THEY NEVER FIRE ANY CONVECTION. FOR NOW HAVE LEANED MORE TOWARDS THE
CONSISTENT ECMWF AS IT ALSO HAS DONE BEST WITH CONVECTION AS OF
LATE. THE MODEL SUGGESTS ELEVATED CONVECTION FIRING AFTER MIDNIGHT
FROM GRAND FORKS DOWN TO AROUND AUSTIN. GIVEN THAT THIS CONVECTION
WILL OCCUR IN THE 1.5-2 INCH PRECIPITABLE WATER STREAM...LOCALLY
HEAVY RAIN COULD OCCUR WITH THE STORMS. ANOTHER MILD TO WARM NIGHT
EXPECTED AGAIN...WARMEST WEST OF THE MS RIVER WITH MORE CLOUDS AND
HIGHER DEWPOINTS.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 334 AM CDT WED AUG 28 2013
..HAZARDS..
1. HEAT. POTENTIAL FOR ANOTHER HEAT ADVISORY COME FRIDAY...
ESPECIALLY ACROSS NORTHEAST IOWA. SATURDAY ALSO HAS A POTENTIAL NEED
FOR A HEAT ADVISORY IF WARM AIR PROGGED THEN ADVECTS IN FASTER.
2. STORMS. THOSE STORMS THAT OCCUR THURSDAY NIGHT ALONG/NORTHEAST OF
I-94 COULD POSE A HEAVY RAIN CONCERN WITH A SMALL RISK OF DAMAGING
WINDS.
..SYNOPTIC OVERVIEW..
28.00Z MODEL GUIDANCE REMAINS IN GOOD AGREEMENT WITH YESTERDAYS
MODEL RUNS OF SHOWING THE SUBTROPICAL RIDGE RETROGRADING INTO THE
FOUR CORNERS REGION THIS WEEKEND. THIS RESULTS IN A GRADUAL FALL OF
500MB HEIGHTS OVER THE FORECAST AREA. ADDITIONALLY...THE BULK OF THE
DEEP TROUGH JUST OFF THE U.S. WEST COAST IS PROGGED TO EJECT OUT
ACROSS SOUTHERN CANADA THIS FRIDAY AND SATURDAY. MODELS HAVE
STRUGGLED A BIT ON THE DEGREE OF AMPLIFICATION WITH THIS TROUGH AS
IT APPROACHES NORTHERN ONTARIO AND LAKE SUPERIOR SUNDAY MORNING...
BUT THEY APPEAR NOW TO HAVE SETTLED DOWN. ALL INDICATIONS ARE THAT
AFTER IT PASSES LAKE SUPERIOR...THE TROUGH WILL THEN DIG INTO THE
EASTERN GREAT LAKES MONDAY AND TUESDAY...WHILE UPPER RIDGING BUILDS
BACK UP OVER THE NORTHERN PLAINS.
..DETAILS..
THE SHORTWAVE OVER NORTH DAKOTA AT 12Z THURSDAY LOOKS TO TRACK
ACROSS NORTHERN MN ON THURSDAY AND INTO UPPER MI THURSDAY NIGHT.
GIVEN THIS TRACK...THE BULK OF THE DYNAMIC FORCING WILL STAY NORTH
OF THE FORECAST AREA...THOUGH TAYLOR AND CLARK COUNTIES COULD GET
BRUSHED. MORE IMPORTANTLY ABOUT THIS SHORTWAVE IS THE ISENTROPIC
LIFT AND LOW LEVEL MOISTURE TRANSPORT OCCURRING WITH IT AND TO ITS
SOUTH. ON THURSDAY...THIS ISENTROPIC LIFT CENTERED ON THE 310-315K
SURFACES AND LOW LEVEL MOISTURE TRANSPORT SLOWLY MARCHES ACROSS THE
FORECAST AREA...GETTING HUNG UP ACROSS WISCONSIN AT 00Z FRIDAY. THE
STRONGEST LIFT/MOISTURE TRANSPORT IS SITUATED NORTH OF THE FORECAST
AREA...BUT STILL WARRANTS 20-40 PERCENT CHANCES. CHANCES INCREASE
ACROSS WISCONSIN THURSDAY NIGHT...ESPECIALLY ALONG/NORTHEAST OF
I-94...AS THE MOISTURE TRANSPORT INCREASES WITH THE NOCTURNAL
INCREASE OF THE LOW LEVEL JET. STRONG MODEL CONSENSUS FOR CONVECTION
THUS 60-70 PERCENT CHANCES SEEM REASONABLE. ALONG AND WEST OF THE MS
RIVER THURSDAY NIGHT...THERE MAY BE VERY LITTLE TO ANY ACTIVITY.
TEMPERATURES ON THURSDAY DEPEND ON HOW MUCH SUN WE SEE...AND WITH
925MB READINGS RANGING FROM 22C EAST TO 27C WEST...THERE COULD BE A
WIDE SPREAD IN HIGHS. FOLLOWED A GUIDANCE CONSENSUS FOR NOW
RESULTING HIGHS IN THE 80S...WARMEST WEST AND IN RIVER VALLEYS.
GUIDANCE CONSENSUS ALSO FOLLOWED FOR LOWS THURSDAY NIGHT.
FOR FRIDAY INTO FRIDAY NIGHT...MODELS CONTINUE TO SHOW A SECOND
SHORTWAVE DROPPING SOUTHEAST OUT OF CENTRAL MN THROUGH THE FORECAST
AREA ON FRIDAY. WITH THIS SHORTWAVE COMING THROUGH AT PEAK HEATING
AND PLENTY OF MOISTURE IN PLACE...NOTED BY PRECIPITABLE WATER VALUES
PROGGED BETWEEN 1.5-1.75 INCHES...NEED TO HAVE SOME CHANCES OF
SHOWERS AND THUNDERSTORMS. MODELS VARY A BIT ON THE STRENGTH OF THIS
SHORTWAVE THUS CHANCES ARE ONLY IN THE 20-30 RANGE. WE MIGHT BE ABLE
TO SQUEEZE IN FRIDAY NIGHT AS DRY PER 28.00Z ECMWF/NAM...HOWEVER...
THE 28.00Z GFS SHOWS WARM AIR ADVECTION RETURNING AHEAD OF A COLD
FRONT MARCHING ACROSS THE DAKOTAS. TO ACCOUNT FOR THE GFS
SCENARIO...HAVE KEPT 20-30 PERCENT CHANCES GOING. FRIDAY HIGHS ARE
ALSO TRICKY AS THEY DEPEND BOTH ON STRENGTH AND TIMING OF THE
SHORTWAVE. THE ECMWF/GFS/CANADIAN ALL SHOW AN INFLUX OF 28-30C 925MB
AIR INTO THE FORECAST AREA...WHICH COULD SUPPORT HIGHS IN THE MID
90S LIKE WE HAVE SEEN. BEST PROBABILITY OF THIS APPEARS TO BE IN
NORTHEAST IOWA WHICH THEN WOULD HAVE THE BEST CHANCE OF NEEDING A
HEAT ADVISORY. THE REST OF THE AREA IS A LITTLE MORE UNCERTAIN.
FOR SATURDAY AND BEYOND...
FOCUS IS ALL ON THAT TROUGH COMING ACROSS SOUTHERN CANADA. MODELS
ARE IN PRETTY GOOD AGREEMENT SHOWING THE COLD FRONT CROSSING THE
AREA DURING THE DAY SUNDAY. AHEAD OF THE FRONT...THERE WILL BE
ANOTHER SURGE OF WARM AIR COMING INTO THE AREA FOR SATURDAY. IF THE
GFS IS CORRECT WITH 925MB TEMPS OF 29-31C...A HEAT ADVISORY WOULD BE
REQUIRED...WHILE THE ECMWF IS MORE SCALED BACK WITH 925MB TEMPS OF
25-28C. FOR NOW THE HIGH TEMPERATURE FORECAST SPLITS THE DIFFERENCE
BETWEEN THESE MODELS. COULD SEE SOME WARM ADVECTION SHOWERS/STORMS
TOO...RIGHT THROUGH SATURDAY NIGHT. ADDITIONALLY...THERE COULD BE
SOME SHOWERS/STORMS THAT ARE FRONTOGENETICALLY DRIVEN AROUND THE
COLD FRONT ON SUNDAY. THEREFORE...20-40 PERCENT CHANCES PER
CONSENSUS ARE IN THE FORECAST. AFTER SUNDAY...DRY CONDITIONS WILL
PREVAIL AS HIGH PRESSURE BUILDS IN AND PERSISTS OVER THE AREA.
TEMPERATURES SUNDAY AND BEYOND ARE TRICKY AS THE 00Z AND 12Z ECMWF
RUNS ALTERNATE ON THE STRENGTH OF COLD ADVECTION. FOR NOW STUCK WITH
A MODEL CONSENSUS FOR HIGHS AND LOWS SUNDAY THROUGH TUESDAY...BUT IF
THE 00Z ECMWF RUNS ARE CORRECT...TEMPERATURES MAY NEED TO BE LOWERED
ANOTHER 5 DEGREES OR SO.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 700 AM CDT WED AUG 28 2013
925 MB WINDS HAVE BROUGHT IN AN IFR DECK OF CLOUDS INTO CENTRAL
AND NORTH CENTRAL WISCONSIN. THESE CLOUDS HAVE FINALLY MADE THERE
WAY INTO KLSE. RAP SUGGESTS THAT THESE CLOUDS WILL GRADUALLY MOVE
SOUTH AND DISSIPATE BY 28.16Z.
MEANWHILE AT KRST...WATCHING A THUNDERSTORM COMPLEX OVER EASTERN
SOUTH DAKOTA. THE HRRR SHOWS THAT THIS SYSTEM WILL MOVE EAST
ACROSS MINNESOTA AND THEN DISSIPATE AS THE LOW LEVEL JET WEAKENS.
AS A RESULT...ONLY EXPECTING SOME 10-15K DECK OF CLOUDS TO MOVE
INTO KRST BY MID MORNING AND THEN LINGER THROUGH THE AFTERNOON.
FOR LATE TONIGHT...THE MODELS ARE SHOWING MODERATE 900-800 MB
FRONTOGENESIS WILL DEVELOP ACROSS SOUTHEAST MINNESOTA AND
NORTHEAST IOWA. THIS IS IN RESPONSE TO THE FRONT OVER NORTHERN
IOWA BEGINNING TO MOVE BACK TO THE NORTH AS A WARM FRONT. THIS WILL
RESULT IN THE DEVELOPMENT OF SCATTERED SHOWERS AND THUNDERSTORMS
ACROSS THE AREA. HOWEVER WAS RATHER UNCERTAIN ON WHETHER THEY
WOULD AFFECT KRST OR NOT...SO LEFT THEM OUT FOR NOW.
&&
.CLIMATE...
ISSUED AT 334 AM CDT WED AUG 28 2013
THE FOLLOWING ARE RECORD HIGHS FOR LA CROSSE AND ROCHESTER
INTO LABOR DAY WEEKEND...GIVEN STILL MORE HEAT FORECAST. FOR MORE
CLIMATE INFORMATION...SEE OUR WEBSITE AND THE TOP NEWS STORY ON
THE RECENT HEAT.
LA CROSSE ROCHESTER
--------- ---------
WED 8/28 97/1955 96/1955
THU 8/29 95/1966 92/2012
FRI 8/30 97/2012 96/1941
SAT 8/31 95/1953 93/1960
SUN 9/1 98/1913 94/1937
MON 9/2 98/1937 94/1929
NORMAL HIGH TEMPERATURES THROUGH THIS PERIOD ARE 78-80 AT LA CROSSE
AND 76-78 AT ROCHESTER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...BOYNE
CLIMATE...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
702 AM CDT WED AUG 28 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM CDT WED AUG 28 2013
..CURRENTLY AS OF 08Z..
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED DEEP TROUGHING
JUST OFF THE U.S. WEST COAST WHILE STRONG SUBTROPICAL RIDGING
CONTINUES TO DOMINATE THE CENTRAL PLAINS. A WEAK RIDGE AXIS EXTENDED
FROM THE SUBTROPICAL RIDGE NORTH INTO THE DAKOTAS. MONSOONAL
MOISTURE AND SHORTWAVES CONTINUE TO ROTATE AROUND THE SUBTROPICAL
RIDGE...FROM ARIZONA INTO THE DAKOTAS AND SOUTHEAST THROUGH THE
FORECAST AREA. REGARDING THE MOISTURE...RAP PRECIPITABLE WATER
ANALYSIS SHOWED VALUES OF 1.5-2 INCHES EXTENDING FROM THE DAKOTAS
SOUTHEASTWARD THROUGH MUCH OF THE FORECAST AREA. EARLY THIS MORNING
ALL MONSOONAL SHORTWAVES WERE EITHER TO THE EAST OR WEST OF THE
FORECAST AREA...RESULTING IN DRY CONDITIONS. AT THE SURFACE A WEAK
COLD FRONT WAS SLOWLY DROPPING SOUTH THROUGH THE FORECAST AREA...NOW
STRETCHED ACROSS NORTHERN IOWA AND FAR SOUTHERN WI. THE FRONT HAS
HAD A HARD TIME SCOURING OUT THE SURFACE MOISTURE WITH DEWPONTS
GENERALLY IN THE LOW 70S ACROSS THE AREA. THE COOLING WITH THE FRONT
HAS BEEN SHALLOW...EVIDENCED ON THE 00Z GRB SOUNDING WITH 925MB
TEMPS OF 22C COMPARED TO 29C AT DVN. SURFACE TEMPERATURES HAVE
FALLEN OFF INTO THE LOW TO MID 70S NORTH OF THE FRONT...AND MID TO
UPPER 70S TO THE SOUTH. THE COOLING INTERACTING WITH THE LINGERING
MOISTURE HAS CAUSED BOTH MIST AND LOW STRATUS TO FORM. VISIBILITIES
ARE LOWEST OVER NORTH CENTRAL WI DUE TO RECENT RAINS. 11-3.9 UM
IMAGERY SHOWED THE BULK OF THE STRATUS ACROSS CENTRAL AND EASTERN
WI.
..HAZARDS..
1. HEAT. NORTH OF I-90...HEAT INDICES ARE FORECAST BETWEEN
90-95...THEREFORE FEEL CONFIDENT NO ADDITIONAL HEAT ADVISORY IS
NEEDED. SOUTH OF I-90 HEAT INDICES ARE EXPECTED TO TOP OUT AROUND
95 TO AT MOST 100. GIVEN THAT THESE ARE BELOW ADVISORY CRITERIA
AND 5 TO 10 DEGREES LOWER THAN THE PAST FEW DAYS...HAVE DECLINED
TO ISSUE A HEAT ADVISORY HERE AS WELL.
2. DENSE FOG ACROSS TAYLOR AND CLARK COUNTIES...WHICH SHOULD
DISSIPATE BETWEEN 9-10 AM.
..SYNOPTIC OVERVIEW..
VERY LITTLE CHANGE IS FORECAST BY MODELS IN THE UPPER AIR PATTERN
DURING THE NEXT 24 HOURS. IF ANYTHING...THE WEAK RIDGE AXIS OVER THE
DAKOTAS GETS FLATTENED OUT AND PUSHED EAST...IN RESPONSE TO A
STRONGER MONSOONAL SHORTWAVE LIFTING INTO NORTH DAKOTA BY 12Z
THURSDAY. AT THE SURFACE...THE WEAK COLD FRONT OVER THE SOUTHERN
PORTION OF THE FORECAST AREA LOOKS TO CONTINUE TO SLOWLY DRIFT
SOUTH...PROGGED TO BISECT IOWA NORTHWEST TO SOUTHEAST BY 00Z. IN
ITS WAKE...HIGH PRESSURE BUILDS IN OVER WISCONSIN. THE FRONT MAY
START TO LIFT BACK TOWARDS THE AREA LATE TONIGHT IN RESPONSE TO WARM
ADVECTION AHEAD OF THE SHORTWAVE MOVING INTO NORTH DAKOTA.
..DETAILS..
SOLAR HEATING WILL HELP TO GRADUALLY IMPROVE VISIBILITIES AND MIX
OUT THE LOW STRATUS AIMING AT SOUTHWEST WI THIS MORNING. BY 18Z ALL
FOG AND STRATUS SHOULD BE GONE. OTHERWISE...DRY ADVECTION IN THE LOW
TO MID LEVELS OF THE ATMOSPHERE ACCOMPANYING THE SURFACE HIGH...
COMBINED WITH CAPPING BY A WARM LAYER AT 750MB...WILL HELP TO KEEP
CONDITIONS DRY TODAY. THE 28.00Z GFS DOES TRY TO CONVECT ACROSS
NORTHEAST IOWA NEAR THE FRONT THIS AFTERNOON...BUT IS THE ONLY MODEL
TO DO SO. HAVE KEPT THE FORECAST DRY DUE TO LIMITED CONVERGENCE ON
THE FRONT AND THE CAPPING POTENTIAL...ALONG WITH ALL OTHER MODELS
SUGGESTING DRY CONDITIONS ON THE FRONT. TEMPERATURES TODAY WILL BE
ABOUT 5 DEGREES COOLER WITH 925MB READINGS DOWN TO 24-26C VERSUS THE
28-30C THAT OCCURRED YESTERDAY. SURFACE DEWPOINTS...ON THE OTHER
HAND...ARE STILL GOING TO BE STUCK IN THE LOW TO PERHAPS MID 70S
SOUTH OF I-90. THUS HEAT INDICES IN THIS AREA OF 95 TO AT MOST 100
ARE EXPECTED. TO THE NORTH...DEWPOINTS SHOULD MIX/FALL INTO THE
60S...KEEPING HEAT INDICES MORE IN THE 90-95 RANGE.
FOR TONIGHT...GOOD MODEL AGREEMENT EXISTS ON THE WARM ADVECTION
SCENARIO. THE BIGGEST ISSUES ARE IF AND WHEN CONVECTION CAN FIRE
FROM THE WARM ADVECTION. HERE AGAIN...THE 28.00Z GFS IS QUICKEST AND
MOST EXPANSIVE...SUGGESTING CONVECTION WEST OF THE MS RIVER ALL
NIGHT. ALL OTHER GUIDANCE WAITS UNTIL AFTER MIDNIGHT...AND IN THE
CASE OF THE 28.00Z REGIONAL CANADIAN AS WELL AS THE 28.00Z NAM...
THEY NEVER FIRE ANY CONVECTION. FOR NOW HAVE LEANED MORE TOWARDS THE
CONSISTENT ECMWF AS IT ALSO HAS DONE BEST WITH CONVECTION AS OF
LATE. THE MODEL SUGGESTS ELEVATED CONVECTION FIRING AFTER MIDNIGHT
FROM GRAND FORKS DOWN TO AROUND AUSTIN. GIVEN THAT THIS CONVECTION
WILL OCCUR IN THE 1.5-2 INCH PRECIPITABLE WATER STREAM...LOCALLY
HEAVY RAIN COULD OCCUR WITH THE STORMS. ANOTHER MILD TO WARM NIGHT
EXPECTED AGAIN...WARMEST WEST OF THE MS RIVER WITH MORE CLOUDS AND
HIGHER DEWPOINTS.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 334 AM CDT WED AUG 28 2013
..HAZARDS..
1. HEAT. POTENTIAL FOR ANOTHER HEAT ADVISORY COME FRIDAY...
ESPECIALLY ACROSS NORTHEAST IOWA. SATURDAY ALSO HAS A POTENTIAL NEED
FOR A HEAT ADVISORY IF WARM AIR PROGGED THEN ADVECTS IN FASTER.
2. STORMS. THOSE STORMS THAT OCCUR THURSDAY NIGHT ALONG/NORTHEAST OF
I-94 COULD POSE A HEAVY RAIN CONCERN WITH A SMALL RISK OF DAMAGING
WINDS.
..SYNOPTIC OVERVIEW..
28.00Z MODEL GUIDANCE REMAINS IN GOOD AGREEMENT WITH YESTERDAYS
MODEL RUNS OF SHOWING THE SUBTROPICAL RIDGE RETROGRADING INTO THE
FOUR CORNERS REGION THIS WEEKEND. THIS RESULTS IN A GRADUAL FALL OF
500MB HEIGHTS OVER THE FORECAST AREA. ADDITIONALLY...THE BULK OF THE
DEEP TROUGH JUST OFF THE U.S. WEST COAST IS PROGGED TO EJECT OUT
ACROSS SOUTHERN CANADA THIS FRIDAY AND SATURDAY. MODELS HAVE
STRUGGLED A BIT ON THE DEGREE OF AMPLIFICATION WITH THIS TROUGH AS
IT APPROACHES NORTHERN ONTARIO AND LAKE SUPERIOR SUNDAY MORNING...
BUT THEY APPEAR NOW TO HAVE SETTLED DOWN. ALL INDICATIONS ARE THAT
AFTER IT PASSES LAKE SUPERIOR...THE TROUGH WILL THEN DIG INTO THE
EASTERN GREAT LAKES MONDAY AND TUESDAY...WHILE UPPER RIDGING BUILDS
BACK UP OVER THE NORTHERN PLAINS.
..DETAILS..
THE SHORTWAVE OVER NORTH DAKOTA AT 12Z THURSDAY LOOKS TO TRACK
ACROSS NORTHERN MN ON THURSDAY AND INTO UPPER MI THURSDAY NIGHT.
GIVEN THIS TRACK...THE BULK OF THE DYNAMIC FORCING WILL STAY NORTH
OF THE FORECAST AREA...THOUGH TAYLOR AND CLARK COUNTIES COULD GET
BRUSHED. MORE IMPORTANTLY ABOUT THIS SHORTWAVE IS THE ISENTROPIC
LIFT AND LOW LEVEL MOISTURE TRANSPORT OCCURRING WITH IT AND TO ITS
SOUTH. ON THURSDAY...THIS ISENTROPIC LIFT CENTERED ON THE 310-315K
SURFACES AND LOW LEVEL MOISTURE TRANSPORT SLOWLY MARCHES ACROSS THE
FORECAST AREA...GETTING HUNG UP ACROSS WISCONSIN AT 00Z FRIDAY. THE
STRONGEST LIFT/MOISTURE TRANSPORT IS SITUATED NORTH OF THE FORECAST
AREA...BUT STILL WARRANTS 20-40 PERCENT CHANCES. CHANCES INCREASE
ACROSS WISCONSIN THURSDAY NIGHT...ESPECIALLY ALONG/NORTHEAST OF
I-94...AS THE MOISTURE TRANSPORT INCREASES WITH THE NOCTURNAL
INCREASE OF THE LOW LEVEL JET. STRONG MODEL CONSENSUS FOR CONVECTION
THUS 60-70 PERCENT CHANCES SEEM REASONABLE. ALONG AND WEST OF THE MS
RIVER THURSDAY NIGHT...THERE MAY BE VERY LITTLE TO ANY ACTIVITY.
TEMPERATURES ON THURSDAY DEPEND ON HOW MUCH SUN WE SEE...AND WITH
925MB READINGS RANGING FROM 22C EAST TO 27C WEST...THERE COULD BE A
WIDE SPREAD IN HIGHS. FOLLOWED A GUIDANCE CONSENSUS FOR NOW
RESULTING HIGHS IN THE 80S...WARMEST WEST AND IN RIVER VALLEYS.
GUIDANCE CONSENSUS ALSO FOLLOWED FOR LOWS THURSDAY NIGHT.
FOR FRIDAY INTO FRIDAY NIGHT...MODELS CONTINUE TO SHOW A SECOND
SHORTWAVE DROPPING SOUTHEAST OUT OF CENTRAL MN THROUGH THE FORECAST
AREA ON FRIDAY. WITH THIS SHORTWAVE COMING THROUGH AT PEAK HEATING
AND PLENTY OF MOISTURE IN PLACE...NOTED BY PRECIPITABLE WATER VALUES
PROGGED BETWEEN 1.5-1.75 INCHES...NEED TO HAVE SOME CHANCES OF
SHOWERS AND THUNDERSTORMS. MODELS VARY A BIT ON THE STRENGTH OF THIS
SHORTWAVE THUS CHANCES ARE ONLY IN THE 20-30 RANGE. WE MIGHT BE ABLE
TO SQUEEZE IN FRIDAY NIGHT AS DRY PER 28.00Z ECMWF/NAM...HOWEVER...
THE 28.00Z GFS SHOWS WARM AIR ADVECTION RETURNING AHEAD OF A COLD
FRONT MARCHING ACROSS THE DAKOTAS. TO ACCOUNT FOR THE GFS
SCENARIO...HAVE KEPT 20-30 PERCENT CHANCES GOING. FRIDAY HIGHS ARE
ALSO TRICKY AS THEY DEPEND BOTH ON STRENGTH AND TIMING OF THE
SHORTWAVE. THE ECMWF/GFS/CANADIAN ALL SHOW AN INFLUX OF 28-30C 925MB
AIR INTO THE FORECAST AREA...WHICH COULD SUPPORT HIGHS IN THE MID
90S LIKE WE HAVE SEEN. BEST PROBABILITY OF THIS APPEARS TO BE IN
NORTHEAST IOWA WHICH THEN WOULD HAVE THE BEST CHANCE OF NEEDING A
HEAT ADVISORY. THE REST OF THE AREA IS A LITTLE MORE UNCERTAIN.
FOR SATURDAY AND BEYOND...
FOCUS IS ALL ON THAT TROUGH COMING ACROSS SOUTHERN CANADA. MODELS
ARE IN PRETTY GOOD AGREEMENT SHOWING THE COLD FRONT CROSSING THE
AREA DURING THE DAY SUNDAY. AHEAD OF THE FRONT...THERE WILL BE
ANOTHER SURGE OF WARM AIR COMING INTO THE AREA FOR SATURDAY. IF THE
GFS IS CORRECT WITH 925MB TEMPS OF 29-31C...A HEAT ADVISORY WOULD BE
REQUIRED...WHILE THE ECMWF IS MORE SCALED BACK WITH 925MB TEMPS OF
25-28C. FOR NOW THE HIGH TEMPERATURE FORECAST SPLITS THE DIFFERENCE
BETWEEN THESE MODELS. COULD SEE SOME WARM ADVECTION SHOWERS/STORMS
TOO...RIGHT THROUGH SATURDAY NIGHT. ADDITIONALLY...THERE COULD BE
SOME SHOWERS/STORMS THAT ARE FRONTOGENETICALLY DRIVEN AROUND THE
COLD FRONT ON SUNDAY. THEREFORE...20-40 PERCENT CHANCES PER
CONSENSUS ARE IN THE FORECAST. AFTER SUNDAY...DRY CONDITIONS WILL
PREVAIL AS HIGH PRESSURE BUILDS IN AND PERSISTS OVER THE AREA.
TEMPERATURES SUNDAY AND BEYOND ARE TRICKY AS THE 00Z AND 12Z ECMWF
RUNS ALTERNATE ON THE STRENGTH OF COLD ADVECTION. FOR NOW STUCK WITH
A MODEL CONSENSUS FOR HIGHS AND LOWS SUNDAY THROUGH TUESDAY...BUT IF
THE 00Z ECMWF RUNS ARE CORRECT...TEMPERATURES MAY NEED TO BE LOWERED
ANOTHER 5 DEGREES OR SO.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 700 AM CDT WED AUG 28 2013
925 MB WINDS HAVE BROUGHT IN AN IFR DECK OF CLOUDS INTO CENTRAL
AND NORTH CENTRAL WISCONSIN. THESE CLOUDS HAVE FINALLY MADE THERE
WAY INTO KLSE. RAP SUGGESTS THAT THESE CLOUDS WILL GRADUALLY MOVE
SOUTH AND DISSIPATE BY 28.16Z.
MEANWHILE AT KRST...WATCHING A THUNDERSTORM COMPLEX OVER EASTERN
SOUTH DAKOTA. THE HRRR SHOWS THAT THIS SYSTEM WILL MOVE EAST
ACROSS MINNESOTA AND THEN DISSIPATE AS THE LOW LEVEL JET WEAKENS.
AS A RESULT...ONLY EXPECTING SOME 10-15K DECK OF CLOUDS TO MOVE
INTO KRST BY MID MORNING AND THEN LINGER THROUGH THE AFTERNOON.
FOR LATE TONIGHT...THE MODELS ARE SHOWING MODERATE 900-800 MB
FRONTOGENESIS WILL DEVELOP ACROSS SOUTHEAST MINNESOTA AND
NORTHEAST IOWA. THIS IS IN RESPONSE TO THE FRONT OVER NORTHERN
IOWA BEGINNING TO MOVE BACK TO THE NORTH AS A WARM FRONT. THIS WILL
RESULT IN THE DEVELOPMENT OF SCATTERED SHOWERS AND THUNDERSTORMS
ACROSS THE AREA. HOWEVER WAS RATHER UNCERTAIN ON WHETHER THEY
WOULD AFFECT KRST OR NOT...SO LEFT THEM OUT FOR NOW.
&&
.CLIMATE...
ISSUED AT 334 AM CDT WED AUG 28 2013
THE FOLLOWING ARE RECORD HIGHS FOR LA CROSSE AND ROCHESTER
INTO LABOR DAY WEEKEND...GIVEN STILL MORE HEAT FORECAST. FOR MORE
CLIMATE INFORMATION...SEE OUR WEBSITE AND THE TOP NEWS STORY ON
THE RECENT HEAT.
LA CROSSE ROCHESTER
--------- ---------
WED 8/28 97/1955 96/1955
THU 8/29 95/1966 92/2012
FRI 8/30 97/2012 96/1941
SAT 8/31 95/1953 93/1960
SUN 9/1 98/1913 94/1937
MON 9/2 98/1937 94/1929
NORMAL HIGH TEMPERATURES THROUGH THIS PERIOD ARE 78-80 AT LA CROSSE
AND 76-78 AT ROCHESTER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR WIZ017-029.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...BOYNE
CLIMATE...AJ
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
642 AM CDT WED AUG 28 2013
UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE
.SHORT TERM...TODAY...TONIGHT...AND THURSDAY
ISSUED AT 405 AM CDT WED AUG 28 2013
FORECAST CONCERNS ON CLOUDS AND FOG THIS MORNING. MODELS FAIRLY
SIMILAR WITH FRONT SOUTH OF CWA. NORTHEAST WINDS AT SFC AND ALOFT BEHIND
FRONT...HAS LED TO WIDESPREAD LOW CLOUDS OFF LAKES TO MOVE OVER
MUCH OF CWA. LESS CLOUDS OVER NORTH CENTRAL HAS LED TO WIDESPREAD
DENSE FOG WITH VISIBILITIES FLUCTUATING AROUND 1/4 MILE. WILL
COVER WITH ADVISORY THROUGH 8AM. GUIDANCE SUGGESTS LOW CLOUDS TO
STICK AROUND A BIT THIS MORNING...WITH RUC SOUNDINGS CARRYING IT
INTO MID/LATE MORNING. HAVE LOWERED MAX TEMPS A BIT TODAY DUE TO
MORNING CLOUDS.
NUMBER OF MODELS CONTINUE TO CARRY LIGHT QPF FAR EASTERN WI TODAY.
NOT SEEING MUCH SUPPORT BESIDES SOME WEAK SURFACE CONVERGENCE...
THOUGH WITH CONTINUED MOIST AIR MASS AND ASSOCIATED INSTABILITY
CANNOT TOTALLY RULE OUT. WILL STAY DRY AT THIS TIME AND ADVISE
NEXT SHIFT.
FRONT BEGINS TO LIFT NORTH TONIGHT WITH BEST DYNAMICS OVER ND/MN.
EXPECT MCS A GOOD POSSIBILITY ON NOSE OF LLVL JET AS SUGGESTED BY MODELS.
GIVEN THERMAL PATTERN AND CORFIDI VECTORS...COMPLEX TO MOVE EAST
AND SOUTHEAST. MODELS SUGGEST COMPLEX MOVING INTO NORTHERN CWA BY
AFTERNOON. HAVE EXPANDED POPS GIVEN SCENARIO.
TEMPERATURES TO CONTINUE TO RUN WARMER THAN NORMAL THIS
PERIOD...THOUGH COOLER THAN PREVIOUS FEW DAYS.
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY
ISSUED AT 405 AM CDT WED AUG 28 2013
ALTHOUGH THERE ARE SOME TIMING DIFFERENCES AMONG THE
MODELS...PRECIPITATION CHANCES SHOULD BE HIGHEST ON THURSDAY
NIGHT AS AN UPPER LEVEL SHORT WAVE TOPS THE RIDGE. THERE WILL ALSO
BE ASSISTANCE FROM SOME 300MB DIVERGENCE AND AN APPROACHING
SURFACE SYSTEM.
THUNDERSTORM CHANCES REMAIN FOR FRIDAY AND SATURDAY WITH WARM AND
HUMID AIR IN PLACE...BUT DO NOT REALLY SEE MUCH FORCING. A COLD
FRONT PUSHING THROUGH TO START NEXT WEEK WILL BRING A CHANCE OF
SHOWERS AND THUNDERSTORMS THROUGH SUNDAY...AND COOLER
TEMPERATURES FOR MONDAY AND TUESDAY.
HAVE GENERALLY USED A MIX OF GUIDANCE AND PREVIOUS FORECAST
TEMPERATURES FOR MAX AND MIN TEMPERATURES DURING THE PERIOD.
&&
.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 631 AM CDT WED AUG 28 2013
STRATUS OFF LAKES EXPANDED OVER REGION OVERNIGHT UNDER NE FLOW.
LINGERING FOG WILL CLEAR EARLY THIS MORNING...THOUGH THE LOW
CLOUDS WILL LINGER INTO MID TO LATE MORNING AS WEAK HIGH PRESSURE
BRINGS DRIER AIR MASS SOUTH. VFR CONDITIONS EXPECTED INTO CONTINUE
INTO THE EVENING...BEFORE FOG RETURNS AFTER MIDNIGHT. &&
.GRB WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 8 AM CDT THIS MORNING FOR WIZ005-
010>012-018-019.
&&
$$
SHORT TERM.....TE
LONG TERM......MG
AVIATION.......
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
112 PM CDT WED AUG 28 2013
.UPDATE...
ISSUED AT 104 PM CDT WED AUG 28 2013
SFC DATA INDICATES THERE IS A PRE-FRONTAL TROF AHEAD OF THE COLD
FRONT. THIS TROF RUNS FROM ROUGHLY KMIW TO SOUTH OF KIKK AS OF
18Z. THE COLD FRONT IS BETWEEN KOLZ AND KALO TO SOUTH OF KVPZ.
SATELLITE TRENDS SHOW THE LOW CLOUDS BREAKING UP BUT STILL IN
PLACE ACROSS THE NORTHERN CWFA. CLOUDS ARE EXPECTED TO REMAIN IN
PLACE FOR MUCH OF THE AFTERNOON WITH A SLOW DISSIPATION. ..08..
UPDATE ISSUED AT 1019 AM CDT WED AUG 28 2013
THE BACK DOOR COOL FRONT IS INTO THE NORTHERN CWFA WITH LOW CLOUDS
IMMEDIATELY BEHIND IT. BASED ON THE 12Z SOUNDING FROM GRB AND
SATELLITE TRENDS...BREAKING UP OF THE CLOUDS OVER THE NORTHERN
CWFA APPEARS QUESTIONABLE THIS AFTERNOON.
AS SUCH...CLOUDS HAVE BEEN INCREASED ACROSS THE NORTH AND
TEMPERATURES LOWERED SOMEWHAT. TEMPERATURES UP NORTH WILL BE
INTERESTING TODAY. IF A SCENARIO SIMILAR TO YESTERDAY IN WISCONSIN
PLAYS OUT THEN SOME AREAS UP NORTH MAY STRUGGLE TO GET MUCH ABOVE
80...OR GET INTO THE 80S AND THEN COLLAPSE BACK INTO THE MID AND
UPPER 70S ONCE THE FRONT MOVES THROUGH.
DIURNAL HEATING AHEAD OF THE FRONT SHOULD SLOW THE SOUTHWARD
PROGRESS OF THE CLOUDS WITH THE FRONT POTENTIALLY STALLING OUT
DURING THE AFTERNOON. CONVERGENCE ALONG THE FRONT IS QUITE WEAK
BUT ONE CANNOT ENTIRELY RULE OUT AN ISOLATED SHOWER OR STORM DUE
TO THE STRONG DIFFERENTIAL HEATING. AS SUCH 10-14 POPS WERE
GENERALLY DONE IN THE VICINITY OF THE FRONT.
THE CURRENT HEAT HEADLINES WILL REMAIN AS IS. THERE ARE QUESTIONS
AS TO WHETHER OR NOT THE NORTHERN EXTEND OF THE ADVISORY AREA WILL
SEE HEAT INDEX READINGS OF 100 DUE TO THE CLOUDS AND FRONTAL
POSITION. ..08..
&&
.SYNOPSIS...
ISSUED AT 341 AM CDT WED AUG 28 2013
MSAS SURFACE ANALYSIS AT 07Z INDICATED THE SURFACE COOL FRONT
REACHING WEST FROM LOW PRESSURE OVER SE LOWER MI ACROSS SOUTHERN
WI...FAR NORTHERN IA...TO A WEAK LOW NW OF VALENTINE NE. SURFACE
DEWPOINTS WERE POOLING IN THE LOWER 70S ALONG AND SOUTH OF THIS AXIS
TO THE HIGHWAY 20 CORRIDOR...WHILE FURTHER SOUTH...MID TO UPPER 60S
WERE COMMON ACROSS THE MUCH OF THE FORECAST AREA. FOG CHANNEL
SATELLITE IMAGERY INDICATED A LARGE FIELD OF POST FRONTAL STRATUS
AND FOG ADVECTING W-SW ACROSS WI...WHILE HINTS OF STRATUS WERE
STARTING TO SHOW UP AHEAD OF THE FRONT BETWEEN KOLZ AND KCGY IN NE
IA. OTHERWISE...IT WAS ANOTHER VERY WARM AND SOMEWHAT MUGGY NIGHT
ACROSS THE REGION WITH TEMPERATURES STILL IN THE MID TO UPPER 70S
AT 3 AM.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 341 AM CDT WED AUG 28 2013
MANY CHALLENGES IN THE FORECAST FOR TODAY AS THE TIMING OF FRONT AND
POSSIBLE CLOUDS WILL IMPACT TEMPERATURES...HUMIDITY AND THE HEAT
ADVISORY HEADLINES.
HAVE FOLLOWED A BLEND OF THE 00Z GFS AND ECMWF BRINGING THE FRONT
INTO FAR NW IL AND EAST CENTRAL IA BY LATE MORNING...THEN
STALLING TO ROUGHLY BISECT THE FORECAST AREA FROM NW TO SE BY
EVENING. ASSOCIATED LOW LEVEL MOISTURE CONVERGENCE WILL KEEP
SURFACE DEWPOINTS IN THE LOWER 70S FOR MUCH OF THE DAY ALONG AND
NE OF THE BOUNDARY WITH THERMAL MIXING IN THE LOW LEVEL NE FLOW
EXPECTED TO BE LIMITED TO AROUND 900 MB. ALONG AND SOUTHWEST OF
THE FRONT...ANOTHER DAY OF DEEP MIXING WITH SIMILAR 850 MB
TEMPERATURES AS YESTERDAY SHOULD YIELD SIMILAR HIGHS...WHILE
DEWPOINTS STAY A FEW DEGREES LOWER. BIG QUESTION WILL BE WHAT
HAPPENS WITH THE BACKDOOR POST FRONTAL STRATUS DECK CURRENTLY
RACING TOWARD THE AREA FROM WI...WHICH AT THE PRESENT RATE IS
SHOWN REACHING NW IL BY 7 AM. THE EARLIER RAP RUNS APPEARED TO
HAVE THE BEST HANDLE ON THIS MOIST AXIS AROUND 925 TO 900
MB...SHOWING IT REACHING INTO THE HIGHWAY 20 CORRIDOR EARLY THIS
MORNING...THEN WASHING OUT WITH DAYTIME HEATING AND WILL FOLLOW
THIS SCENARIO FOR NOW COUNTING ON MOSTLY SUNNY SKIES OVER THE
ENTIRE AREA MOST OF THE DAY.
WILL THUS HAVE HIGHS FROM THE MID 80S ACROSS THE NORTHEAST...90 TO
LOWER 90S ACROSS THE CENTRAL THIRD...THEN MID 90S IN THE SOUTH.
THIS MAY AGAIN THREATEN RECORD HIGHS FOR THIS DATE...ESPECIALLY AT
BRL...LISTED IN THE CLIMATE SECTION BELOW. WHEN COMBINED WITH
SURFACE DEWPOINTS LINGERING IN THE LOWER TO MID 70S WHERE THE
FRONT EVENTUALLY STALLS OUT...HEAT INDEX VALUES SHOULD EXCEED 100
BY AFTERNOON. WELL SOUTHWEST OF THE FRONT...DEWPOINTS WILL BE
LOWER...BUT AMBIENT TEMPERATURES INTO THE MID AND POSSIBLY UPPER
90S WILL RESULT IN WIDESPREAD 100 TO 103 HEAT INDEX VALUES IN THE
AFTERNOON. HAVE KEPT THE PREVIOUS HEAT ADVISORY GOING UNTIL 00Z AND
ADDED BUCHANAN AND JONES COUNTY IN EASTERN IA WHERE THE HEAT INDEX
NOW LOOKS LIKELY TO EXCEED 100.
WHILE SOME MODELS ARE ADVERTISING QPF ALONG AND NE OF THE BOUNDARY
TODAY AND TONIGHT...THIS LOOKS OVERDONE GIVEN THE CAPPING WARM
TEMPERATURES ALOFT. THIS CAP WEAKENS SOME TONIGHT...BUT WITH A
STRONG TRIGGER LACKING...WILL KEEP A DRY FORECAST. WITH THE FRONT
LINGERING OVER THE AREA...WARM AND SOMEWHAT HUMID AIR WILL REMAIN IN
PLACE OVER ESPECIALLY THE CENTRAL AND SOUTH. HAVE KEPT LOWS FROM THE
MID 60S NORTHEAST TO THE LOWER 70S ACROSS THE SOUTH.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 341 AM CDT WED AUG 28 2013
FORECAST FOCUS ON HOT AND HUMID AND MAINLY DRY THROUGH SATURDAY...
THEN MUCH COOLER BY LABOR DAY.
THURSDAY THROUGH SATURDAY NIGHT...RIDGING ALOFT AND A CAPPED
ATMOSPHERE TO REMAIN THROUGH MUCH OF THIS TIME FRAME. THERE IS A
SMALL CHANCE OF THUNDERSTORMS MAINLY FRIDAY NIGHT AS A RIDGE RIDER
TRACKS ACROSS THE MIDWEST. THE SURFACE BOUNDARY WILL LIFT BACK TO
THE NORTHEAST OF THE CWA BY FRIDAY. MAXIMUM TEMPERATURES ON THURSDAY
WILL BE IN THE UPPER 80S NORTHEAST TO THE MID 90S SOUTHWEST...AND IN
THE 90S OVER ALL THE CWA BOTH FRIDAY AND SATURDAY. THESE WILL BE
SCORCHERS WITH DEWPOINTS AT LEAST IN THE LOWER 70S. HIGHEST HEAT
INDEX VALUES LOOK TO BE 100 TO 105 IN OUR SOUTHERN COUNTIES ON
THURSDAY...AND OVER MUCH OF THE CWA FOR BOTH FRIDAY AND SATURDAY.
HEAT ADVISORY HEADLINES WILL MORE THAN LIKELY NEED TO BE ISSUED FOR
MUCH OF THIS PERIOD. IF BURLINGTON IOWA RECEIVES NO RAINFALL BY THE
END OF THIS MONTH THEY WILL GO INTO THE BOOKS WITH ONLY A TRACE OF
RAIN FOR THE ENTIRE MONTH OF AUGUST...AND THE DRIEST AUGUST ON
RECORD!
SUNDAY AND SUNDAY NIGHT...TIMING OF THE COLD FRONT WILL BE CRITICAL
AS FAR AS CHANCES FOR THUNDERSTORMS AND MAXIMUM TEMPERATURES. DID
NOTICE THE ECMWF HAS BACKED OFF ON THE REALLY CHILLY AIR FROM A
COUPLE OF RUNS AGO. NOW THE ECMWF BRINGS ONLY THE 8C 850 MB
TEMPERATURE AS FAR SOUTH AS NORTHERN IL INSTEAD OF THE 2C FROM
EARLIER RUNS. CURRENT GRID TEMPERATURES MAY BE TOO WARM ON SUNDAY
DEPENDING ON TIMING OF THE FRONT...AMOUNT OF CLOUD COVER AND ANY
RAINFALL. THERE DOES APPEAR TO BE AT LEAST A CHANCE FOR A FEW
THUNDERSTORMS TO FORM ALONG THE FRONT BUT IN A DRY SPELL YOU DON`T
WANT TO GET YOUR HOPES UP. BUT ONCE AGAIN THIS WILL DEPEND ON THE
TIMING OF THE FRONT AND AMOUNT OF INSTABILITY AND MOISTURE. WELL...
AT LEAST ON PAPER THERE IS ENOUGH FORCING FROM THE DIGGING TROUGH TO
HOPEFULLY TRIGGER AT LEAST SCATTERED STORMS.
NEXT WEEK...HIGH PRESSURE WILL BRING A PLEASANT LABOR DAY AND THE
EARLY PART OF THE SHORTENED WORK WEEK. SHOULD BE A REALLY NICE DAY
FOR GRILLING OUT IN THE BACKYARD. MAXIMUM TEMPERATURES SHOULD END UP
IN THE 70S NORTH AND 80S SOUTH ALONG WITH COMFORTABLE HUMIDITY.
NIGHTTIME LOWS WILL DROP INTO THE 50S TO LOWER 60S EARLY IN THE
WEEK. ACCORDING TO MY FAVORED ECMWF MODEL THERE WILL BE A BRIEF WARM
UP BY MID WEEK FOLLOWED SHORTLY THEREAFTER BY ANOTHER COLD FRONT.
HOWEVER...MUCH OF THE FIRST WEEK OF SEPTEMBER LOOKS ON THE DRY SIDE.
HAASE
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 104 PM CDT WED AUG 28 2013
VFR WX WILL CONTINUE AT KCID/KMLI/KBRL THROUGH 06Z/29. HIGH
PRESSURE WILL CONTINUE TO BUILD INTO THE GREAT LAKES AND SLOWLY
PUSH A COLD FRONT TOWARD SOUTHEAST IOWA. AT KDBQ...MVFR
CONDITIONS WILL SLOWLY IMPROVE TO VFR THROUGH 00Z/29. AFT 06Z/29
LIGHT WINDS AND HIGH LOW LEVEL MOISTURE SHOULD ALLOW MVFR VSBYS TO
DEVELOP. THE POTENTIAL DOES EXIST FOR IFR/LIFR CONDITIONS WITH FOG
PRIOR TO SUNRISE. ..08..
&&
.CLIMATE...
ISSUED AT 341 AM CDT WED AUG 28 2013
RECORD HIGHS FOR AUGUST 28...
MOLINE.........96 IN 1953
CEDAR RAPIDS...96 IN 1955
DUBUQUE........97 IN 1984
BURLINGTON.....96 IN 1945
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR BENTON-BUCHANAN-
CEDAR-DES MOINES-HENRY IA-IOWA-JEFFERSON-JOHNSON-JONES-
KEOKUK-LEE-LINN-LOUISA-MUSCATINE-SCOTT-VAN BUREN-WASHINGTON.
IL...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR HANCOCK-HENDERSON-
HENRY IL-MCDONOUGH-MERCER-ROCK ISLAND-WARREN.
MO...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR CLARK-SCOTLAND.
&&
$$
UPDATE...08
SYNOPSIS...SHEETS
SHORT TERM...SHEETS
LONG TERM...12
AVIATION...08
CLIMATE...SHEETS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
431 PM EDT WED AUG 28 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 412 PM EDT WED AUG 28 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE OVER
THE CNTRL CONUS RESULTING IN ACYC FLOW FROM THE NRN PLAINS THROUGH
THE UPPER MS VALLEY AND GREAT LAKES. A WEAK SHORTWAVE TROUGH FROM
NEAR CYPL-CYHD INTO NW MN SUPPORTED SOME SCT SHRA/TSRA. A MORE
SIGNIFICANT UPSTREAM SHRTWV WAS MOVING FROM IDAHO INTO WRN MONTANA.
MID CLOUDS OVER MN INTO NW WI LEFTOVER FROM EARLIER CONVECTION AND A
WAA PATTERN UPSTREAM...WERE SPREADING INTO WRN UPPER MI. AT THE
SFC...A WEAK RIDGE FROM NRN ONTARIO INTO UPPER MI HAS BROUGHT MOSTLY
CLEAR SKIES AND LIGHT WINDS ACROSS UPPER MI AND PROMINENT LAKE
BREEZES. INLAND...MIXING IN THE SLIGHTLY DRIER AIRMASS PWAT AROUND
1.0 INCH (NEAR NORMAL) HAS DROPPED DEWPOINTS TO AROUND 60F.
WITH MAINLY CLEAR SKIES AND LIGHT WINDS...SOME FOG WILL DEVELOP
OVERNIGHT. HOWEVER...THERE HAS BEEN ENOUGH LOW LEVEL DRYING SO THAT
THE FOG IS NOT EXPECTED TO BECOME AS DENSE OR WIDESPREAD AS LAST
NIGHT. IN ADDITION...SOME MID CLOUDS MOVING INTO THE WEST MAY ALSO
LIMIT THE RADIATIONAL COOLING. OTHERWISE...MIN TEMPS SHOULD AGAIN
DROP TO AROUND 60 INLAND WITH LOWER TO MID 60S ALONG THE GREAT
LAKES.
AS THE NRN ROCKIES SHORTWAVE MOVES THROUGH SRN SASK AND MANITOBA TO
NRN MN WAA AHEAD OF THE SYSTEM WILL BRING INCREASING CLOUDS ACROSS
THE CWA. SOME SHRA/TSRA SUPPORTED BY 310K-315K ISENTROPIC ASCENT
NORTH OF A WARM FRONT INTO SRN MN MAY BRING SOME SHRA/TSRA FROM WRN
LAKE SUPERIOR AND NW WI INTO THE FAR WEST LATE. HOWEVER...ONLY LOW
END POPS WERE INCLUDED AS THE BULK OF ANY PCPN IS EXPECTED TO HOLD
OFF UNTIL AFT 00Z.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 431 PM EDT WED AUG 28 2013
ONE OF THE CONCERNS INHIBITING WIDESPREAD CONVECTION THURSDAY NIGHT
WILL BE THE FACT THAT THE SFC LOW/MAIN TROUGH WILL REMAIN TO OUR S.
SO WHILE THE SHORTWAVE CROSSES UPPER MI...STORMS MAY BE A BIT MORE
ELEVATED. THE LATEST NON-EURO RUNS DO INDICATE THE POTENTIAL FOR
MODERATE TO HEAVY RAIN...PRIMARILY ACROSS LAKE SUPERIOR...WITH 2-3IN
FALLING SOMEWHERE ACROSS THE CWA. EXACT TIMING AND PLACEMENT OF THE
HEAVIER RAIN WILL NEED TO BE PINNED DOWN A BIT LATER. THERE WAS
ENOUGH CERTAINTY TO KEEP LIKELY POPS GOING OVER THE FAR W LATE
THURSDAY EVENING...AND ACROSS MUCH OF THE W HALF OVERNIGHT...BEFORE
CONTINUING THE TRACK AROUND THE 500MB RIDGE AND SHIFTING TO OUR SE
FRIDAY MORNING. THE MOST UNSTABLE AIR WILL LIKELY BE ACROSS THE
INTERIOR W AND TO OUR SW...CLOSER TO THE SFC LOW.
A TEMPORARY RIDGE WILL EXPAND ACROSS THE UPPER GREAT LAKES FRIDAY
EVENING AS THE SFC LOW STRETCHING FROM N LAKE MI TO E IA EXITS
ACROSS LOWER MI. DIMINISHED THE CHANCE OF SHOWERS/TS FOR FRIDAY
NIGHT AND SATURDAY...AHEAD OF THE DEEPENING CANADIAN LOW. THE SFC
LOW IS STILL FIGURED TO BE OVER LAKE WINNIPEG AROUND 12Z
SATURDAY...AND SHIFT ACROSS S ONTARIO/LAKE SUPERIOR SUNDAY
MORNING-AFTERNOON. THE ECMWF IS REMAINS THE DEEPEST AT THE SFC AND
ALOFT WITH THIS FEATURE...BUT THE 12Z GFS IS CATCHING UP. WILL
CONTINUE TO LEAN THE FCST A BIT CLOSER TO THE ECMWF SOLUTION FOR
MUCH OF THIS PERIOD. QUICKER THAN ITS RUN FROM YESTERDAY...THE 12Z
ECMWF DEVELOPS THE 500MB LOW OVER ONTARIO SUNDAY MORNING /ABOUT
18HRS FASTER THAN THE GFS/. THIS WILL BE THE START OF OUR NEAR TO
BELOW NORMAL TEMPERATURES...AS ANOTHER LOW DIVES INTO EASTERN CANADA
ON WEDNESDAY. THE RESULT WILL BE A SIGNIFICANT TROUGH SUPPRESSING
THE STRONG HIGH TO OUR SW...AND 60S AND LOW 70S RETURNING TO THE
FCST FOR MONDAY...BEFORE MODERATING BACK TO NORMAL /70S/ BY
WEDNESDAY. STRONGER NW WINDS OF 10-20KTS ACROSS LAKE SUPERIOR AND
850MB TEMPS OF 4-6C SHOULD KEEP TEMPS IN THE 60S MONDAY...ALONG WITH
THE POTENTIAL FOR SHOWERS/DRIZZLE NEAR LAKE SUPERIOR. WAY OUT IN THE
FUTURE...THE ECMWF DOES HAVE 0 TO -2C TEMPS ACROSS LAKE SUPERIOR ON
THURSDAY. WILL WILL NEED TO WAIT AND SEE ON THAT ONE. EITHER
WAY...THE WARM AIR LOOKS TO BE DONE FOR A WHILE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 134 PM EDT WED AUG 28 2013
VFR CONDITIONS WILL PREVAIL INTO THE EVENING UNTIL FOG REDEVELOPS
WITH THE LOSS OF DAYTIME HEATING. MAINLY MVFR CONDITIONS ARE EXPECTED
AT THE THREE TAF SITES DUE TO SOME FOG FROM A FEW HOURS AFTER SUNSET
THROUGH 12Z. ALTHOUGH CONFIDENCE IN FOG INTENSITY IS LOW...THE FOG IS
NOT EXPECTED TO BECOME AS DENSE AS LAST NIGHT. HOWEVER...THERE MAY BE
SOME BRIEF PERIODS WITH VSBY DOWN TO VLIFR.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 412 PM EDT WED AUG 28 2013
PATCHY FOG WILL PERSIST THROUGH THROUGH THURSDAY AS RELATIVELY HIGH
DEWPOINTS REMAIN THROUGH THE WEEK. DRIER AIR BEGINS MOVING IN FOR
THE WEEKEND... LIMITING FOG POTENTIAL FOR THE WEEKEND. LIGHT WINDS
WILL PREVAIL THROUGH MUCH OF THE FORECAST PERIOD AS THE PRESSURE
GRADIENT REMAINS LIGHT UNDER THE INFLUENCE OF RIDGING ALOFT. THE
PRESSURE GRADIENT WILL TIGHTEN SUNDAY WITH THE PASSAGE OF A LOW
PRESSURE SYSTEM TO THE NORTH OF LAKE SUPERIOR. BEHIND THE COLD
FRONT...NORTHWEST WINDS ARE EXPECTED TO INCREASE INTO THE 15 TO 25
KNOT RANGE. WAVES WILL MAY ALSO BUILD INTO THE 3 TO 7 FOOT RANGE
WITH COLDER AIR MOVING IN.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
413 PM EDT WED AUG 28 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 412 PM EDT WED AUG 28 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE OVER
THE CNTRL CONUS RESULTING IN ACYC FLOW FROM THE NRN PLAINS THROUGH
THE UPPER MS VALLEY AND GREAT LAKES. A WEAK SHORTWAVE TROUGH FROM
NEAR CYPL-CYHD INTO NW MN SUPPORTED SOME SCT SHRA/TSRA. A MORE
SIGNIFICANT UPSTREAM SHRTWV WAS MOVING FROM IDAHO INTO WRN MONTANA.
MID CLOUDS OVER MN INTO NW WI LEFTOVER FROM EARLIER CONVECTION AND A
WAA PATTERN UPSTREAM...WERE SPREADING INTO WRN UPPER MI. AT THE
SFC...A WEAK RIDGE FROM NRN ONTARIO INTO UPPER MI HAS BROUGHT MOSTLY
CLEAR SKIES AND LIGHT WINDS ACROSS UPPER MI AND PROMINENT LAKE
BREEZES. INLAND...MIXING IN THE SLIGHTLY DRIER AIRMASS PWAT AROUND
1.0 INCH (NEAR NORMAL) HAS DROPPED DEWPOINTS TO AROUND 60F.
WITH MAINLY CLEAR SKIES AND LIGHT WINDS...SOME FOG WILL DEVELOP
OVERNIGHT. HOWEVER...THERE HAS BEEN ENOUGH LOW LEVEL DRYING SO THAT
THE FOG IS NOT EXPECTED TO BECOME AS DENSE OR WIDESPREAD AS LAST
NIGHT. IN ADDITION...SOME MID CLOUDS MOVING INTO THE WEST MAY ALSO
LIMIT THE RADIATIONAL COOLING. OTHERWISE...MIN TEMPS SHOULD AGAIN
DROP TO AROUND 60 INLAND WITH LOWER TO MID 60S ALONG THE GREAT
LAKES.
AS THE NRN ROCKIES SHORTWAVE MOVES THROUGH SRN SASK AND MANITOBA TO
NRN MN WAA AHEAD OF THE SYSTEM WILL BRING INCREASING CLOUDS ACROSS
THE CWA. SOME SHRA/TSRA SUPPORTED BY 310K-315K ISENTROPIC ASCENT
NORTH OF A WARM FRONT INTO SRN MN MAY BRING SOME SHRA/TSRA FROM WRN
LAKE SUPERIOR AND NW WI INTO THE FAR WEST LATE. HOWEVER...ONLY LOW
END POPS WERE INCLUDED AS THE BULK OF ANY PCPN IS EXPECTED TO HOLD
OFF UNTIL AFT 00Z.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 414 AM EDT WED AUG 28 2013
HIGH PRESSURE WILL BE OVER NORTHERN LAKE MICHIGAN AT THE START OF
THE PERIOD AND LEAD TO CLEAR SKIES OVER THE AREA. THE CLEAR SKIES
AND LINGERING MOIST LOW LEVELS WILL LIKELY LEAD TO SOME LINGERING
PATCHY FOG DURING THE FIRST COUPLE OF HOURS IN THE MORNING. AFTER A
CLEAR START TO THE MORNING...CLOUDS AND PRECIPITATION CHANCES WILL
BE ON THE INCREASE HEADING INTO THE AFTERNOON. THIS IS DUE TO THE
NEXT SHORTWAVE ROUNDING THE UPPER RIDGE AXIS IN THE DAKOTAS. THERE
SHOULD BE AN MCS ASSOCIATED WITH THE INITIAL SHORTWAVE EXITING NORTH
DAKOTA THURSDAY MORNING ON THE NOSE OF THE LOW LEVEL JET AND WAA.
THIS COMPLEX WILL FOLLOW THE MEAN FLOW AND INSTABILITY AXIS TO THE
EAST-SOUTHEAST AND THROUGH NORTHWEST WISCONSIN AND MAINLY JUST
BRUSHING UPPER MICHIGAN LATE THUSDAY AFTERNOON THROUGH THURSDAY
NIGHT. THE SECONDARY SHORTWAVE WILL FOLLOW A SIMILAR TRACK ALTHOUGH
A TOUCH FARTHER SOUTH FOR LATE THURSDAY NIGHT INTO FRIDAY MORNING.
WILL CONTINUE THE HIGHEST POPS ALONG THE WISCONSIN BORDER AND KEEP
AT HIGH END CHANCES AND LOW END LIKELY VALUES AT THIS POINT. SINCE
THE NAM/GEM SLIDE THE SHORTWAVE FARTHER NORTH...WILL KEEP SOME
PRECIPITATION MENTION IN THE FORECAST FOR THE REST OF UPPER MICHIGAN
ON THURSDAY NIGHT INTO FRIDAY. BASED ON THE INSTABILITY/SHEAR
VALUES...THINK THE BEST CHANCES FOR SEVERE WEATHER WILL STAY
SOUTH OF THE AREA AND MAYBE BRUSH THE SOUTHERN TIER OF COUNTIES.
LABOR DAY WEEKEND IS STILL MARKED WITH SOME DIFFERENCES IN THE
TIMING/INSTENSITY OF THE STRONG SHORTWAVE TROUGH EJECTING OUT OF
THE PACIFIC NORTHWEST ON THURSDAY NIGHT. THIS SHORTWAVE WILL ROUND
THE UPPER RIDGE ON SATURDAY (WHICH IS TRANSITIONING WEST INTO THE
ROCKIES DURING THAT TIME) AND MOVE THROUGH THE UPPER GREAT LAKES
REGION SATURDAY NIGHT THROUGH MONDAY. A SURFACE LOW ASSOCIATED WITH
THE SHORTWAVE WILL MOVE EAST ACROSS ONTARIO DURING THAT TIME FRAME
AND DRAG A COLD FRONT ACROSS UPPER MICHIGAN (MOST LIKELY SATURDAY
NIGHT). WILL HIGHLIGHT THE BEST CHANCES FOR RAIN DURING THAT
SATURDAY NIGHT PERIOD...BUT INCLUDE SLIGHT CHANCES BEFORE/AFTER DUE
TO THE TIMING DIFFERENCES. THIS COLD FRONT WILL BRING MUCH COOLER
TEMPERATURES TO THE AREA FOR SUNDAY AND MONDAY. THERE MAY BE ENOUGH
WARM AIR AROUND ON SUNDAY TO KEEP HIGHS AROUND NORMAL...BUT MONDAY
LOOKS TO BE BELOW NORMAL AS 850MB TEMPS FALL TO AROUND 6C. HIGH
PRESSURE WILL BUILD OVER THE AREA FOR MONDAY INTO TUESDAY AND LEAD
TO DRY WEATHER...ALTHOUGH THERE MAY BE SOME UPSLOPE DRIZZLE EARLY ON
MONDAY IN THE FAVORED AREAS NEAR LAKE SUPERIOR. EXPECT CLOUDS TO BE
OVER THE AREA FOR MONDAY UNDER THE NORTH-NORTHWESTERLY FLOW BUT THEY
SHOULD PULL OUT MONDAY NIGHT. WITH THE UPPER RIDGE BUILDING BUILDING
BACK TO THE EAST...EXPECT TEMPERATURES TO BEGIN WARMING CLOSER TO
NORMAL FOR TUESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 134 PM EDT WED AUG 28 2013
VFR CONDITIONS WILL PREVAIL INTO THE EVENING UNTIL FOG REDEVELOPS
WITH THE LOSS OF DAYTIME HEATING. MAINLY MVFR CONDITIONS ARE EXPECTED
AT THE THREE TAF SITES DUE TO SOME FOG FROM A FEW HOURS AFTER SUNSET
THROUGH 12Z. ALTHOUGH CONFIDENCE IN FOG INTENSITY IS LOW...THE FOG IS
NOT EXPECTED TO BECOME AS DENSE AS LAST NIGHT. HOWEVER...THERE MAY BE
SOME BRIEF PERIODS WITH VSBY DOWN TO VLIFR.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 412 PM EDT WED AUG 28 2013
PATCHY FOG WILL PERSIST THROUGH THROUGH THURSDAY AS RELATIVELY HIGH
DEWPOINTS REMAIN THROUGH THE WEEK. DRIER AIR BEGINS MOVING IN FOR
THE WEEKEND... LIMITING FOG POTENTIAL FOR THE WEEKEND. LIGHT WINDS
WILL PREVAIL THROUGH MUCH OF THE FORECAST PERIOD AS THE PRESSURE
GRADIENT REMAINS LIGHT UNDER THE INFLUENCE OF RIDGING ALOFT. THE
PRESSURE GRADIENT WILL TIGHTEN SUNDAY WITH THE PASSAGE OF A LOW
PRESSURE SYSTEM TO THE NORTH OF LAKE SUPERIOR. BEHIND THE COLD
FRONT...NORTHWEST WINDS ARE EXPECTED TO INCREASE INTO THE 15 TO 25
KNOT RANGE. WAVES WILL MAY ALSO BUILD INTO THE 3 TO 7 FOOT RANGE
WITH COLDER AIR MOVING IN.
&&
.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 ALBUQUERQUE NM
255 PM MDT WED AUG 28 2013
.DISCUSSION...
A DEEP SUBTROPICAL MOISTURE SURGE HAS ARRIVED OVER SOUTHERN NM AS A
WELL DEFINED INVERTED TROUGH SHIFTS SLOWLY NORTHWEST OF THE AREA.
CIRA BLENDED TOTAL PWAT VALUES ARE 150-175PCT OF NORMAL OVER THE
EL PASO AREA...AND THIS MOISTURE WILL ADVECT NORTH THRU TONIGHT ON
INCREASING 700-500MB SSE FLOW. ABUNDANT CLOUD COVER HAS LIMITED
CONVECTION ACROSS MUCH OF THE SOUTH THUS FAR HOWEVER A SLUG OF
NMRS SHRA/TSRA DEVELOPING AROUND I-10 AND IS SLIDING NORTH. LATEST
RUC AND HRRR SHOW THIS MASS OF PRECIP MOVING NORTH UP THE RGV AND
SOUTHERN HIGH TERRAIN INTO THIS EVENING BEFORE TAPERING OFF AFTER
MIDNIGHT. HAVE TIGHTENED UP POPS FURTHER WITH FOCUS OVER CATRON...
SOCORRO...AND LINCOLN COUNTIES.
CLOUD COVER ASSCD WITH THIS AREA OF PRECIP WILL LINGER INTO EARLY
THURSDAY AND LIKELY LIMIT CONVECTION AGAIN UNTIL LATE DAY WITHIN
ITS PERIPHERY. MODELS DO SHOW A SIMILAR FEATURE TMRW BUT FARTHER
NORTH WITH A MASS OF SHRA/TSRA SLIDING ACROSS THE SW HIGH TERRAIN
AND SOUTHERN PORTIONS OF THE NM CONT DVD THRU MID DAY. CONVECTION
SHOULD BE MORE WIDESPREAD FOR THE REMAINDER OF THE HIGH TERRAIN
AFT 3 OR 4 PM AS THETA-E RIDGE VALUES ARE HIGHER AND LIFTED INDICES
MORE UNSTABLE.
THE REAL JUICE AND FORCING MOVES INTO THE REGION FRIDAY THRU MONDAY
WITH PWAT VALUES AVERAGING AROUND 1.2 INCHES. FOCUS FOR CONVECTION
WILL BE OVER NORTHERN AND WESTERN NM FRIDAY...THEN OVER CENTRAL
AND NORTHERN NM FOR SATURDAY THROUGH MONDAY AS A BACK DOOR FRONTAL
BNDRY MOVES SW OVER THE AREA. LCL HEAVY RAIN THREAT WILL INCREASE
AND FLASH FLOOD WATCHES ARE POSSIBLE FOR AT LEAST BURN SCAR AREAS
THRU THE LABOR DAY HOLIDAY. FOLKS PLANNING OUTDOOR ACTIVITIES OVER
THE HOLIDAY WEEKEND SHOULD PREPARE FOR WET WEATHER. TEMPS IN THIS
PATTERN WILL BE CLOSER TO SEASONAL NORMALS.
GUYER
&&
.FIRE WEATHER...
BASED ON SATELLITE IMAGERY...ABUNDANT MOISTURE IS TRYING TO FLOW UP
FROM MEXICO. SOUTHERN PORTIONS OF THE AREA...ESPECIALLY SOCORRO
COUNTY WESTWARD WILL EXPERIENCE WETTING RAIN TODAY AND TONIGHT.
ISOLATED WETTING RAIN WILL BE FOUND FURTHER NORTH OVER THE NORTHWEST
AND NORTH CENTRAL MOUNTAINS. THE MID LEVEL DRY INTRUSION WHICH WAS
SQUARELY OVER THE FORECAST AREA YESTERDAY HAS SHIFTED
NORTH/NORTHEAST...THUS THE LOWEST HUMIDITY VALUES ARE FOUND THERE.
OVERALL...HUMIDITY VALUES HAVE TRENDED UP TODAY.
MOISTURE WILL CONTINUE TO MOVE NORTH AND WESTWARD ON THURSDAY. THIS
WILL SET THE STAGE FOR INCREASE WETTING RAIN COVERAGE CENTRAL
MOUNTAINS WESTWARD DURING THE AFTERNOON AND EVENING. A PRETTY DECENT
WETTING RAIN SIGNAL SHOWS UP ACROSS THE NORTHWEST AND WEST CENTRAL
HIGHLANDS. DRIER AND MORE STABLE AIR WILL BE FOUND OVER THE EASTERN
PLAINS. HUMIDITY VALUES FOR THE MOST PART WILL TREND UP EVEN MORE
ALTHOUGH LOWER SLIGHTLY ACROSS THE FAR EAST. HIGH TEMPERATURES WILL
BE ABOVE NORMAL NORTH AND EAST AS THE HIGH CENTER SHIFTS MORE OVER
PORTIONS OF THE SOUTHERN ROCKIES AND PLAINS INCLUDING OVER PARTS OF
NEW MEXICO. DUE TO THE PROXIMITY OF THE HIGH PRESSURE
ALOFT...VENTILATION RATES WILL LOWER ACROSS MOST OF THE AREA.
THE WEATHER MODELS DEPICT A BROAD HIGH PRESSURE AREA OVER THE DESERT
SOUTHWEST AND SOUTHERN ROCKIES FRIDAY INTO SATURDAY. SMALLER
ATMOSPHERIC WAVES WILL ROTATE AROUND THIS HIGH PRESSURE AREA AND
KICK OFF SCATTERED TO NUMEROUS WETTING THUNDERSTORMS. WESTERN AND
NORTHERN PORTIONS OF NM WILL MOST LIKELY EXPERIENCE THESE WAVES.
DRIER AND MORE STABLE AIR ALOFT WILL REMAINED CENTERED OVER EASTERN
NM. THE FLOW ALOFT WILL BE RATHER WEAK DURING THIS PERIOD SO SOME
POOR VENTILATION RATES SHOW UP IN AREAS. HIGH TEMPERATURES WILL
GENERALLY BE NEAR NORMAL WEST AND SEVERAL DEGREES ABOVE NORMAL EAST.
MINIMUM HUMIDITY VALUES WILL ALSO BE IN THE 20S EAST AND CANT RULE
OUT SOME UPPER TEENS. THUS CURING OF THE FINE OR GRASS FUELS WOULD MOST
LIKELY CONTINUE THERE.
BOTH THE GFS AND ECMWF MODELS SHOW AN UPTICK IN WETTING
THUNDERSTORMS OVER THE ENTIRE FORECAST AREA SUNDAY INTO EARLY NEXT
WEEK. THE UPPER HIGH WEAKENS SOME AND ALLOWS THE ATMOSPHERE TO
BECOME MORE UNSTABLE. ABUNDANT LOW LEVEL MOISTURE WOULD ALSO BEGIN
TO FILL IN ACROSS THE FORECAST AREA AND ALLOW FOR SCATTERED TO
NUMEROUS WETTING STORMS. THIS PERIOD COULD BECOME SOME SORT OF PSEUDO
MONSOON BURST EVENT. WILL CONTINUE TO MONITOR THE MODELS AND GET A
BETTER GAUGE FOR CONFIDENCE AS TIME GOES ON. CONDITIONS WOULD THEN
GRADUALLY IMPROVE SOME ACROSS THE EASTERN PLAINS.
50
&&
.AVIATION...
18Z TAF CYCLE
ABUNDANT MOISTURE WILL FLOW UP FROM MEXICO TODAY. SOUTHERN
PORTIONS OF THE FORECAST AREA WILL SEE AN INCREASE IN SH/TS
COVERAGE AS A RESULT. BASED ON MODEL FORECASTS GUP AND ROW HAVE THE
BEST SHOT OF EXPERIENCING SOME OF THIS MOISTURE. WILL USE VCSH AT
THIS TIME BECAUSE THE HEAVY CLOUD COVER WILL CREATE A MORE STABLE
SITUATION. MVFR CONDITIONS ARE NOT ANTICIPATED AT THIS TIME BUT MT
TOP OBSCD WILL BE POSSIBLE ACROSS THE SOUTH AS CIGS LOWER.
RAINFALL COULD CONTINUE MOST OF THE OVERNIGHT ACROSS THE SOUTH AND
LOWER CIGS EVEN FURTHER THERE. ALSO HAVE A VCSH AT SAF. ISOLD
CELLS COULD ROLL OFF THE SANGRE DE CRISTOS TOWARDS SAF THIS
AFTERNOON SO WILL BITE ON THAT BASED ON A HIGHER RESOLUTION WEATHER
MODEL. WILL MONITOR ACCORDINGLY. ADDITIONAL STORM COVERAGE
ANTICIPATED ACROSS THE AREA ON THURSDAY.
50
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 62 88 64 87 / 10 10 10 20
DULCE........................... 51 83 54 84 / 10 20 20 30
CUBA............................ 54 80 56 83 / 10 20 20 30
GALLUP.......................... 56 81 58 82 / 20 20 30 30
EL MORRO........................ 53 74 54 78 / 20 30 30 40
GRANTS.......................... 55 77 56 81 / 20 20 20 30
QUEMADO......................... 54 76 56 80 / 40 40 30 30
GLENWOOD........................ 60 78 61 82 / 50 50 30 20
CHAMA........................... 48 77 50 78 / 20 30 30 40
LOS ALAMOS...................... 56 80 58 83 / 10 20 20 20
PECOS........................... 55 78 57 81 / 20 10 10 20
CERRO/QUESTA.................... 51 80 53 82 / 10 20 20 20
RED RIVER....................... 48 72 50 75 / 20 30 30 40
ANGEL FIRE...................... 47 76 48 79 / 20 30 30 30
TAOS............................ 52 82 54 85 / 10 20 10 20
MORA............................ 53 78 54 81 / 10 10 20 20
ESPANOLA........................ 56 86 58 88 / 10 10 10 10
SANTA FE........................ 56 78 58 81 / 20 20 10 20
SANTA FE AIRPORT................ 59 85 60 86 / 20 10 10 20
ALBUQUERQUE FOOTHILLS........... 63 81 62 86 / 20 20 20 20
ALBUQUERQUE HEIGHTS............. 65 84 65 87 / 20 20 10 20
ALBUQUERQUE VALLEY.............. 63 85 64 89 / 20 10 10 5
ALBUQUERQUE WEST MESA........... 65 84 66 89 / 20 10 10 10
LOS LUNAS....................... 63 84 64 89 / 20 20 10 10
RIO RANCHO...................... 64 84 65 89 / 20 10 10 20
SOCORRO......................... 64 81 65 90 / 30 30 10 5
SANDIA PARK/CEDAR CREST......... 58 80 61 83 / 20 20 20 30
TIJERAS......................... 59 82 60 85 / 20 20 20 20
MORIARTY/ESTANCIA............... 59 82 58 85 / 20 20 10 20
CLINES CORNERS.................. 58 81 59 83 / 20 20 10 30
GRAN QUIVIRA.................... 59 76 59 84 / 30 20 10 20
CARRIZOZO....................... 62 76 62 85 / 40 30 10 5
RUIDOSO......................... 57 70 60 79 / 50 40 20 20
CAPULIN......................... 56 86 59 86 / 5 10 10 10
RATON........................... 55 88 56 87 / 5 10 5 10
SPRINGER........................ 57 89 57 90 / 5 10 5 10
LAS VEGAS....................... 55 84 56 85 / 10 10 10 20
CLAYTON......................... 63 93 64 94 / 5 5 0 0
ROY............................. 60 90 62 91 / 5 10 0 5
CONCHAS......................... 66 95 66 96 / 5 5 0 5
SANTA ROSA...................... 65 92 65 94 / 10 5 0 5
TUCUMCARI....................... 68 96 68 98 / 5 5 0 0
CLOVIS.......................... 65 91 66 93 / 10 5 0 0
PORTALES........................ 65 91 66 93 / 10 5 0 0
FORT SUMNER..................... 66 92 67 95 / 10 5 0 0
ROSWELL......................... 68 93 68 95 / 20 10 0 0
PICACHO......................... 62 83 61 89 / 30 20 5 5
ELK............................. 59 76 59 83 / 50 30 10 10
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 2 AM MDT THURSDAY FOR THE FOLLOWING ZONES...
NMZ508-526.
&&
$$
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
1127 AM MDT WED AUG 28 2013
.AVIATION...
18Z TAF CYCLE
ABUNDANT MOISTURE WILL FLOW UP FROM MEXICO TODAY. SOUTHERN
PORTIONS OF THE FORECAST AREA WILL SEE AN INCREASE IN SH/TS
COVERAGE AS A RESULT. BASED ON MODEL FORECASTS GUP AND ROW HAVE THE
BEST SHOT OF EXPERIENCING SOME OF THIS MOISTURE. WILL USE VCSH AT
THIS TIME BECAUSE THE HEAVY CLOUD COVER WILL CREATE A MORE STABLE
SITUATION. MVFR CONDITIONS ARE NOT ANTICIPATED AT THIS TIME BUT MT
TOP OBSCD WILL BE POSSIBLE ACROSS THE SOUTH AS CIGS LOWER.
RAINFALL COULD CONTINUE MOST OF THE OVERNIGHT ACROSS THE SOUTH AND
LOWER CIGS EVEN FURTHER THERE. ALSO HAVE A VCSH AT SAF. ISOLD
CELLS COULD ROLL OFF THE SANGRE DE CRISTOS TOWARDS SAF THIS
AFTERNOON SO WILL BITE ON THAT BASED ON A HIGHER RESOLUTION WEATHER
MODEL. WILL MONITOR ACCORDINGLY. ADDITIONAL STORM COVERAGE
ANTICIPATED ACROSS THE AREA ON THURSDAY.
50
&&
.PREV DISCUSSION...928 AM MDT WED AUG 28 2013...
WATER VAPOR LOOP CONTINUES TO SUPPORT A WELL DEFINED INVERTED
TROUGH AXIS PUSHING SLOWLY NORTH ACROSS SOUTHERN NM. LATEST
CIRA BLENDED TPW VALUES ARE HOVERING AT 100-125 PCT OF NORMAL.
SIGNIFICANT CLOUD COVER PUSHING NORTH INTO FAR SOUTHERN AREAS
OF THE CWA IS INHIBITING WARMING BUT THE 15Z LAPS DATA SHOWS A
DESTABILIZING AIRMASS MOVING SLOWLY NORTHWARD FROM THE EL PASO
AREA. LATEST SHORT-TERM MODEL GUIDANCE INCLUDING THE HRRR AND RUC
SHOW WIDESPREAD SHRA/TSRA DEVELOPMENT BY EARLY THIS AFTERNOON
IN THIS AREA SHIFTING NORTH WITH VERY LITTLE ACTIVITY OVER THE
REMAINDER OF NM. RAISED POPS TO LIKELY FOR MORE OF SOUTHERN
LINCOLN AND CATRON COUNTIES AND ADDED MORE OF A CHAVES COUNTY
AS WELL TO MENTION.
GUYER
.PREV DISCUSSION...316 AM MDT WED AUG 28 2013...
ELY WAVE/UPPER LEVEL CIRCULATION OVER TEXAS PANHANDLE THROWING A
LITTLE KINK IN THE FLOW AROUND UPPER HIGH CENTER OVER MISSOURI.
SOUTHERLY/SELY FLOW ALOFT CONTINUING TO TAP MID AND UPPER LEVEL
SUBTROPICAL MOISTURE EARLY THIS MORNING. THUNDERSTORM ACTIVITY
WILL BE ON THE INCREASE TODAY...ESPECIALLY FOR SOUTHERN AREAS
WHERE PWATS RISE TO NEAR AN INCH. ELSEWHERE...ISOLATED STORMS OVER
THE NORTHERN MOUNTAIN WILL LIKELY GET A LATE START AS SUBSIDENCE
ON THE BACK/WEST SIDE OF UPPER LEVEL WAVE KEEPS DRY UPPER LEVEL
AIR OVER THIS ARE LONGER. MODERATE TO STRONG MID-LEVEL SPEED MAX
ASSOCIATED WITH YET ANOTHER ELY WAVE MOVES THROUGH THE SOUTHERN
ZONES THIS EVENING. THIS FEATURE LIKELY TO KEEP SOME STORMS GOING
OVER THE SW MOUNTAINS OVERNIGHT.
DEEP MOISTURE ON THE RELATIVELY STRONG SOUTH/SELY WINDS AT THE SFC
AND ALOFT SURGES NORTHWARD TONIGHT AND THURSDAY MORNING...WITH A HEALTHY
CROP OF SCT STORMS EXPECTED THURSDAY. ADDITIONALLY...1 INCH PWAT ISOLINE SURGES
NORTHWARD INTO NORTHERN NM THURSDAY MORNING...MAKING SCATTERED
HEAVY RAINERS A VERY GOOD BET. FAVORED AREAS AT THIS POINT LIKELY
THE SOUTHWEST AND SOUTH CENTRAL MOUNTAINS. ISSUED A FLASH FLOOD
WATCH FOR THESE TWO ZONES GIVEN THE SUSCEPTIBILITY OF THE WHITEWATER
BALDY AND LITTLE BEAR BURN SCARS.
UPPER HIGH BUILDS BACK WESTWARD...NOW CENTERED OVER CENTRAL
COLORADO THURSDAY EVENING. SUBTROPICAL MOISTURE PLUME SHIFTS WWD
BUT PLENTY OF RESIDUAL MOISTURE FOR SCT CONVECTION WESTERN AND NRN
MOUNTAINS WITH ISOLD STORMS ELSEWHERE. SUBTROPICAL MOISTURE PLUME WRAPS
AROUND UPPER HIGH CIRCULATION...MOVING BACK INTO NORTHERN AND CENTRAL NM
FOR THE WEEKEND. COMBINATION OF ABOVE AVG PWATS AND ABOVE AVG SFC
TEMPS SHOULD LEAD TO HEALTHY ROUNDS OF AFTERNOON AND EVENING
CONVECTION EACH DAY THIS WEEKEND INTO EARLY NEXT WEEK.
33
.FIRE WEATHER...
ATMOSPHERIC MOISTURE WILL BE ON THE INCREASE TODAY INTO THURSDAY AS
AN EASTERLY WAVE MOVES ACROSS NORTHERN MEXICO AND SOUTHERN AZ/NM.
CHANCES FOR WETTING RAIN AND RELATIVE HUMIDITIES WILL BE TRENDING UP
AS WELL...ESPECIALLY SOUTH AND WEST. GOOD TO EXCELLENT HUMIDITY
RECOVERIES FORECAST TO PERSIST MOST AREAS. THROUGH FRIDAY...LOWEST
HUMIDITIES AND LOWEST CHANCES FOR WETTING RAIN WILL BE EASTERN
PLAINS...CLOSER TO THE SUBSIDENT SIDE OF THE UPPER HIGH CIRCULATION.
CONVECTIVE RECYCLING MODE THROUGH THE WEEKEND WITH THE UPPER HIGH
ANCHORED OVER THE AREA. SOME DRYING/WARMING FORECAST THROUGH THE
WEEKEND WITH NO ADDITIONAL INFLUX OF MOISTURE. DECENT AGREEMENT
BETWEEN THE 00Z GFS AND ECMWF SOLUTIONS OF THE POSITION OF THE UPPER
HIGH THROUGH THE MIDDLE OF NEXT WEEK OVER OUR AREA...WITH ANY
MONSOONAL MOISTURE PLUME MAINLY WEST OF NEW MEXICO OVER ARIZONA.
EASTERN PLAINS LOOK TO HAVE LITTLE TO NO CHANCE FOR WETTING RAINS
THROUGH THE MIDDLE OF NEXT WEEK. NEAR-TERM CONTINUED DRYING OF FINE
FUELS EASTERN PLAINS LOOKS LIKE A GOOD BET.
11
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR THE FOLLOWING ZONES...
NMZ508-526.
&&
$$
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
316 PM EDT WED AUG 28 2013
.SYNOPSIS...
SCATTERED SHOWERS AND THUNDERSTORMS WILL OCCUR AHEAD OF A COLD
FRONT...WHICH SHOULD ARRIVE FROM THE NORTH LATE THURSDAY
AFTERNOON. THIS FRONT WILL STALL SOUTH OF CHARLESTON FRIDAY...BUT
IS EXPECTED TO RETURN NORTH THIS WEEKEND WITH HOT AND HUMID
CONDITIONS DEVELOPING EARLY NEXT WEEK. A STRONGER COLD FRONT WILL
ARRIVE FROM THE NORTH TUESDAY OR WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 2 PM WEDNESDAY...WARMER AND MORE MOIST AIRMASS IN PLACE
TODAY. TEMPS BETWEEN 85 AND 90 MOST PLACES WITH DEWPOINT TEMPS
AROUND 70 IN A SW FLOW BETWEEN TROUGH OF LOW PRESSURE INLAND AND WEAK
HIGH PRESSURE OFF SHORE. MID TO HIGH CLOUDS WILL CONTINUE TO
STREAM DOWN INTO THE CAROLINAS FROM ASSOCIATED CONVECTION/PCP
UPSTREAM ROUNDING THE TOP OF THE MID TO UPPER RIDGE. THESE CLOUDS
WILL SPREAD SOUTH FILTERING OUT THE SUN AND PRODUCING MOSTLY
CLOUDY SKIES THIS AFTERNOON...ESPECIALLY ACROSS NORTHERN TIER
COUNTIES. THIS WILL ACT TO SLOW DOWN HEATING IN PLACES AND PRODUCE
SLIGHTLY LOWER TEMPS...BUT AS OF NOW...EXPECTING TEMPS TO REACH
BETWEEN 85 AND 90 AIDED BY A WARMER DOWNSLOPE WESTERLY FLOW
THROUGH THE LOW LEVELS.
WITH A PREVAILING SOUTHWEST FLOW AT THE SURFACE...SEA BREEZE SHOULD
PENETRATE FARTHER INLAND OVER NORTH CAROLINA COUNTIES. MOISTURE
RICH AIR WILL PUSH INLAND BEHIND SEA BREEZE WITH GREATEST RISE IN
DEWPOINTS UP CLOSE TO 75 ACROSS NORTH CAROLINA COASTAL
COUNTIES...WHERE MODELS SHOW HIGHEST CAPE VALUES. DEWPOINT TEMPS
INLAND WILL DECREASE REMAINING BELOW 70 IN MOST PLACES. DECENT
SUBSIDENCE INVERSION ALOFT WILL KEEP MOST CONVECTIVE ACTIVITY AT
BAY THIS AFTERNOON...BUT CONVERGENCE ALONG SEA BREEZE COULD TRIGGER
ISLD SHWRS/TSTMS...MAINLY OVER NC COASTAL COUNTIES. ANOTHER FOCUS
OF CONVECTION WILL BE ALONG TROUGH INLAND...MAINLY WEST OF LOCAL
CWA...BUT CLOUDS STREAMING IN FROM THE NORTH WILL CONTINUE TO
INHIBIT THIS ACTIVITY. WILL KEEP WITH MAINLY ISOLATED FOR THIS
AFTERNOON AS SOME PCP COULD SHIFT INTO OUR NORTHWESTERN COUNTIES.
A LINGERING AREA OF MAINLY STRATIFORM PCP WILL ALSO TRACK MAINLY
ACROSS NORTH CAROLINA PRODUCING MAINLY LIGHTER PCP.
MID-LEVEL PERTURBATIONS WILL RIDE AROUND THE MID TO UPPER RIDGE
AS IT SHIFTS WEST PRODUCING A MORE DIRECT STEERING FLOW INTO OUR
AREA. AT THE MOMENT...WATER VAPOR SATELLITE IMAGERY SHOWING
ASSOCIATED CONVECTION WELL UPSTREAM OVER WEST VA/VA BORDER AND
FURTHER NORTH LINING UP NICELY WITH THESE SHORTWAVES. AS THESE
PERTURBATIONS MOVES SOUTH OVER NORTH CAROLINA THEY SHOULD ACT TO
INITIATE SOME CONVECTION...MAINLY NORTH BUT THEY MAY MOVE CLOSE
ENOUGH TO HELP ENHANCE ACTIVITY ALONG THE SEA BREEZE AND INLAND
TROUGH LATER TODAY.
PRECIPITABLE WATER VALUES WILL CONTINUE TO INCREASE REACHING JUST
OVER 2 INCHES THROUGH LATE DAY INTO TONIGHT...BUT THE MID LEVELS
REMAIN FAIRLY DRY AND LIFT WILL REMAIN RATHER WEAK THROUGH THIS
PERIOD. A DECENT CAP WILL REMAIN OVER THE AREA THROUGH THE DAY.
THEREFORE WILL CONTINUE TO INCLUDE ONLY ISOLATED TO LOW END SCT POPS
ACROSS MAINLY NORTH CAROLINA COUNTIES LATE DAY AND TONIGHT. CLOUDS
AND PCP OVERNIGHT WILL KEEP LOWS ABOVE NORMAL...LOWER TO MID 70S.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 PM WEDNESDAY...THE LONGWAVE TROUGH JUST OFF THE EAST COAST
WILL HAVE SEVERAL SHORTWAVES MOVE THROUGH IT OVER THE NEXT SEVERAL
DAYS. ONE SHORTWAVE WILL MOVE OFF THE CAROLINA COAST THIS
EVENING FOLLOWED BY A MUCH WEAKER ONE THURSDAY NIGHT. THIS IS ALL
OCCURRING WITHIN A LARGE REGION OF NORTHWEST FLOW ALOFT COMING
DOWN OFF THE RIDGE OVER THE PLAINS STATES.
A SURFACE COLD FRONT CURRENTLY OVER OHIO AND INDIANA WILL SWEEP
SOUTHEASTWARD TOMORROW...MOVING INTO THE EASTERN CAROLINAS DURING
THE LATE AFTERNOON AND EARLY EVENING HOURS. THIS TIMING IS IN
BETWEEN THE TWO SHORTWAVES ALOFT AND THERE ARE NO FAVORABLY
POSITIONED UPPER JETS TO ASSIST WITH SYNOPTIC LIFT. FOR THIS
REASON MY POPS ARE ONLY IN THE 20-40 PERCENT RANGE TOMORROW...ALL
THIS DESPITE A FRONT ARRIVING JUST AFTER PEAK HEATING ALONG WITH
SURFACE-BASED CAPE AS HIGH AS 1500 J/KG. THE BOUNDARY SHOULD DRIFT
SOUTH TO NEAR SAVANNAH GEORGIA FRIDAY BEFORE STALLING AND
RETURNING NORTH LATER IN THE WEEKEND. AS ONE WOULD EXPECT MODELS
ARE ALL OVER THE PLACE WITH THEIR DEPICTION OF WHERE SHOWERS AND
T-STORMS WILL MOST LIKELY BE TOMORROW. 09Z SREF POPS LOOK A GREAT
DEAL LIKE THE 12Z GFS WHICH GIVES SOME CONFIDENCE TO PLACING THE
BEST PRECIP POTENTIAL ALONG THE COAST THURSDAY AFTERNOON...SHIFTING
SOUTHWESTWARD TOWARD INTERIOR EASTERN SOUTH CAROLINA DURING THE
EVENING HOURS. STABLE POST-FRONTAL AIR SHOULD END ANY LINGERING
SHOWERS ACROSS SE NORTH CAROLINA AFTER MIDNIGHT.
FAIRLY WEAK INSTABILITY FRIDAY SHOULD PRECLUDE MUCH SHOWER
ACTIVITY ACROSS SE NORTH CAROLINA...BUT A LITTLE BETTER MOISTURE
IN THE VICINITY OF THE STALLED FRONT SHOULD PRODUCE 20-30 PERCENT
COVERAGE OF SHOWERS AND T-STORMS ACROSS EASTERN SOUTH CAROLINA.
FRIDAY NIGHT THE FRONT WILL BEGIN TO RETURN NORTHWARD...BUT ANY
INCREASE IN SHOWER COVERAGE SHOULD REMAIN OFFSHORE.
THE NAM AND GFS ARE IN VERY GOOD AGREEMENT WITH TEMPERATURE TRENDS
OVER THE NEXT COUPLE OF DAYS...AND MY FORECAST IS VERY CLOSER TO
BOTH. BOTH MODELS ARE MUCH WARMER THAN THE EXPERIMENTAL ECMWF MOS
FOR HIGH TEMPERATURES THURSDAY. MODELS SHOW THERE WILL BE AT
LEAST SCATTERED MID-LEVEL ALTOCUMULUS AT THE TOP OF THE LOW-
LEVEL MOISTURE PLUME NEAR 10000 FT AGL...BUT I HAVE DOUBTS IT WILL
REMAIN DENSE ENOUGH DURING THE DAYLIGHT HOURS TO HOLD TEMPERATURES
DOWN SIGNIFICANTLY.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 3 PM WEDNESDAY...NORMAL SUMMERTIME CONDITIONS TO START THE
PERIOD WITH RATHER ZONAL FLOW ALOFT AND TEMPS AT OR SLIGHTLY ABOVE
SEASONABLE LEVELS. WITH BERMUDA HIGH PRESSURE OFFSHORE AND TROUGHING
SLOWLY DEVELOPING AT 500MB...PIEDMONT TROUGH AND SEA BREEZE DIURNAL
CONVECTION WILL BE POSSIBLE EACH AFTN THROUGH THE WKND. EARLY NEXT
WEEK...TROUGH AT 500MB DEEPENS ACROSS THE EAST...REINFORCED BY A
SERIES OF SHORTWAVES DROPPING AROUND THE BASE. THIS TROUGH WILL PICK
UP THE MOISTURE FROM A WEAK TROPICAL WAVE NEAR FLORIDA...AND THIS
WILL ENHANCE CONVECTION/RAINFALL POTENTIAL ON MONDAY. HIGHEST POP
WILL BE SHOWN MONDAY FOR THIS REASON...BUT TEMPS WILL CONTINUE TO
WARM TO SEVERAL DEGREES ABOVE CLIMO FOR THE EARLY WEEK. THIS IMPULSE
WILL MOVE AWAY TUESDAY...BEFORE A COLD FRONT WILL CROSS THE AREA
LATE TUESDAY INTO WEDNESDAY WITH INCREASED CONVECTIVE POTENTIAL ONCE
AGAIN. TEMPS WILL FALL BACK TO SEASONABLE OR SLIGHTLY BELOW AT THE
END OF THE PERIOD.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 18Z...VISIBLE SATELLITE IMAGERY SHOWS WIDESPREAD CIRRUS
FILTERING INTO OUR AREA THIS AFTN. VFR WILL PREVAIL TODAY WITH
FEW/SCT CU AND SCT/BKN CIRRUS ACROSS THE CWA. AN UPPER DISTURBANCE
IS APPROACHING FROM THE NORTH...BUT THE LATEST HRRR RUNS INDICATE
THE SHOWERS ASSOCIATED WITH IT SHOULD REMAIN TO OUR NORTH AND EAST.
WILL STILL MENTION VCSH FOR KILM/KLBT AFTER 00Z...BUT PCPN CHANCES
APPEAR MARGINAL ATTM. INCREASING BOUNDARY LAYER WINDS AND MID-LEVEL
CLOUDINESS WILL INHIBIT FOG FORMATION OVERNIGHT. A COLD FRONT WILL
SAG SOUTHWARD TOWARD THE CAROLINAS ON THURSDAY. SCATTERED SHOWERS
AND T-STORMS ARE EXPECTED AHEAD OF THE BOUNDARY...AND SO HAVE ADDED
VCSH BEGINNING AROUND 14-15Z. T-STORMS WILL LIKELY BE MORE PREVALENT
AFTER THE VALID PERIOD...SO DID NOT MENTION THUNDER IN THESE TAFS.
EXTENDED OUTLOOK...EARLY MORNING FOG POSSIBLE FRIDAY AND SATURDAY.
ISOLATED TSRA SUNDAY AND MONDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 2 PM WEDNESDAY...SOUTHWEST FLOW WILL CONTINUE BETWEEN TROUGH
INLAND AND WEAK HIGH PRESSURE OFF SHORE. PERTURBATIONS RIDING
AROUND THE MID TO UPPER RIDGE LOCATED OVER THE CENTRAL CONUS WILL
ACT TO SHARPEN THE TROUGH A BIT OVERNIGHT PRODUCING A SLIGHT RISE IN
WINDS. THE SEA BREEZE THIS AFTERNOON HAS HELPED TO PRODUCE A
GREATER ON SHORE AND SOUTHERLY PUSH WHICH WILL HELP TO PUSH SEAS UP
TO 3 TO 4 FT BY LATE DAY. WINDS WILL VEER TO MORE W-SW TOWARD
MORNING AND THEREFORE EXPECT SEAS THEM TO REMAIN HIGHER OFF
SHORE...WHILE THE NEAR SHORE DROPS SLIGHTLY. OVERALL EXPECT SEAS
TO REMAIN BETWEEN 2 AND 4 FT.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 PM WEDNESDAY...WEAK LOW PRESSURE NEAR THE OUTER BANKS WILL
MOVE OFFSHORE THURSDAY AFTERNOON...ALLOWING A COLD FRONT TO SINK
SOUTH ACROSS THE AREA DURING THE EVENING AND OVERNIGHT HOURS. THIS
FRONT SHOULD BE ACCOMPANIED BY SCATTERED SHOWERS AND THUNDERSTORMS
WHICH WILL FOLLOW THE FRONT SOUTH INTO CENTRAL AND SOUTHERN SOUTH
CAROLINA FOR FRIDAY. THE FRONT WILL BEGIN TO RETURN NORTH LATER
THIS WEEKEND.
MODERATE SOUTHWEST WINDS AHEAD OF THE FRONT THURSDAY COULD EXCEED
15 KNOTS...PARTICULARLY DURING THE MORNING HOURS. THESE WINDS WILL
PRODUCE SEAS RANGING AS HIGH AS 3 FT NEARSHORE ALONG THE BRUNSWICK
COUNTY COASTLINE...AND PERHAPS 4 FT OFFSHORE NEAR FRYING PAN
SHOALS. WINDS WILL WEAKEN AND VEER NEAR THE FRONT...THEN SHOULD
INCREASE TO NEAR 15 KNOTS AGAIN FROM THE NORTHEAST ON FRIDAY.
WEAKER ONSHORE WINDS ARE EXPECTED FRIDAY NIGHT.
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 3 PM WEDNESDAY...HIGH PRESSURE OFFSHORE WILL GRADUALLY SHIFT
FURTHER EAST...ALLOWING FOR WINDS TO TURN FROM THE SE TO THE SW ON
SATURDAY. AS THIS OCCURS...A COLD FRONT WILL SLOWLY APPROACH FROM
THE NW...PINCHING THE GRADIENT AND CAUSING WINDS TO INCREASE
STEADILY FROM THE SW...BECOMING 15-20 KTS AHEAD OF THE FRONT ON
MONDAY. WHILE SATURDAY SEAS WILL BE AROUND 2 FT WITH A WEAK
SOUTHERLY WIND CHOP AND SE GROUND SWELL...THE SPECTRUM WILL BECOME
INCREASINGLY WIND-WAVE DOMINATED...BECOMING 3-5 FT ON MONDAY...AND A
SCEC MAY BE NECESSARY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TRA
NEAR TERM...RGZ
SHORT TERM...TRA
LONG TERM...JDW
AVIATION...BJR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
159 PM EDT WED AUG 28 2013
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO WEAKEN AS A COLD FRONT APPROACHES
FROM THE NORTH...BRINGING AN INCREASING CHANCE OF SHOWERS AND
THUNDERSTORMS THROUGH THURSDAY NIGHT. HIGH PRESSURE WILL BUILD
SOUTHEAST INTO THE REGION THIS WEEKEND AND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 2 PM WEDNESDAY...WARMER AND MORE MOIST AIRMASS IN PLACE
TODAY. TEMPS BETWEEN 85 AND 90 MOST PLACES WITH DEWPOINT TEMPS
AROUND 70 IN A SW FLOW BETWEEN TROUGH OF LOW PRESSURE INLAND AND WEAK
HIGH PRESSURE OFF SHORE. MID TO HIGH CLOUDS WILL CONTINUE TO
STREAM DOWN INTO THE CAROLINAS FROM ASSOCIATED CONVECTION/PCP
UPSTREAM ROUNDING THE TOP OF THE MID TO UPPER RIDGE. THESE CLOUDS
WILL SPREAD SOUTH FILTERING OUT THE SUN AND PRODUCING MOSTLY
CLOUDY SKIES THIS AFTERNOON...ESPECIALLY ACROSS NORTHERN TIER
COUNTIES. THIS WILL ACT TO SLOW DOWN HEATING IN PLACES AND PRODUCE
SLIGHTLY LOWER TEMPS...BUT AS OF NOW...EXPECTING TEMPS TO REACH
BETWEEN 85 AND 90 AIDED BY A WARMER DOWNSLOPE WESTERLY FLOW
THROUGH THE LOW LEVELS.
WITH A PREVAILING SOUTHWEST FLOW AT THE SURFACE...SEA BREEZE SHOULD
PENETRATE FARTHER INLAND OVER NORTH CAROLINA COUNTIES. MOISTURE
RICH AIR WILL PUSH INLAND BEHIND SEA BREEZE WITH GREATEST RISE IN
DEWPOINTS UP CLOSE TO 75 ACROSS NORTH CAROLINA COASTAL
COUNTIES...WHERE MODELS SHOW HIGHEST CAPE VALUES. DEWPOINT TEMPS
INLAND WILL DECREASE REMAINING BELOW 70 IN MOST PLACES. DECENT
SUBSIDENCE INVERSION ALOFT WILL KEEP MOST CONVECTIVE ACTIVITY AT
BAY THIS AFTERNOON...BUT CONVERGENCE ALONG SEA BREEZE COULD TRIGGER
ISLD SHWRS/TSTMS...MAINLY OVER NC COASTAL COUNTIES. ANOTHER FOCUS
OF CONVECTION WILL BE ALONG TROUGH INLAND...MAINLY WEST OF LOCAL
CWA...BUT CLOUDS STREAMING IN FROM THE NORTH WILL CONTINUE TO
INHIBIT THIS ACTIVITY. WILL KEEP WITH MAINLY ISOLATED FOR THIS
AFTERNOON AS SOME PCP COULD SHIFT INTO OUR NORTHWESTERN COUNTIES.
A LINGERING AREA OF MAINLY STRATIFORM PCP WILL ALSO TRACK MAINLY
ACROSS NORTH CAROLINA PRODUCING MAINLY LIGHTER PCP.
MID-LEVEL PERTURBATIONS WILL RIDE AROUND THE MID TO UPPER RIDGE
AS IT SHIFTS WEST PRODUCING A MORE DIRECT STEERING FLOW INTO OUR
AREA. AT THE MOMENT...WATER VAPOR SATELLITE IMAGERY SHOWING
ASSOCIATED CONVECTION WELL UPSTREAM OVER WEST VA/VA BORDER AND
FURTHER NORTH LINING UP NICELY WITH THESE SHORTWAVES. AS THESE
PERTURBATIONS MOVES SOUTH OVER NORTH CAROLINA THEY SHOULD ACT TO
INITIATE SOME CONVECTION...MAINLY NORTH BUT THEY MAY MOVE CLOSE
ENOUGH TO HELP ENHANCE ACTIVITY ALONG THE SEA BREEZE AND INLAND
TROUGH LATER TODAY.
PRECIPITABLE WATER VALUES WILL CONTINUE TO INCREASE REACHING JUST
OVER 2 INCHES THROUGH LATE DAY INTO TONIGHT....BUT THE MID LEVELS
REMAIN FAIRLY DRY AND LIFT WILL REMAIN RATHER WEAK THROUGH THIS
PERIOD. A DECENT CAP WILL REMAIN OVER THE AREA THROUGH THE DAY.
THEREFORE WILL CONTINUE TO INCLUDE ONLY ISOLATED TO LOW END SCT POPS
ACROSS MAINLY NORTH CAROLINA COUNTIES LATE DAY AND TONIGHT. CLOUDS
AND PCP OVERNIGHT WILL KEEP LOWS ABOVE NORMAL...LOWER TO MID 70S.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...COLD FRONT WILL MOVE INTO THE REGION THEN
STALL EARLY THU. WEAK PATTERN ALOFT WILL KEEP THE FRONT STALLED IN
THE AREA THROUGH THE END OF THE PERIOD. BERMUDA HIGH AND WEAK
SURFACE HIGH BUILDING SOUTH FROM THE GREAT LAKES WILL STRUGGLE FOR
CONTROL FOR MUCH OF THE PERIOD. ON THU THE FRONT AND WEAK
SHORTWAVE IN NORTH-NORTHWEST FLOW ALOFT WILL TRY AND GENERATE
SOME AFTERNOON PRECIP. THE ONE CATCH IS THE SUBSIDENCE BEHIND THE
STRONGER EXITING SHORTWAVE. THIS COULD HINDER POP ALONG THE NC
COAST...ESPECIALLY DURING EARLY AFTERNOON THU. WITH THAT SAID WILL
MAINTAIN CHC POP AS THERE IS PLENTY OF MOISTURE...PRECIPITABLE
WATER VALUES ARE OVER 2 INCHES THU...AND DIURNAL INSTABILITY ALONG
WITH THE WEAK CONVERGENCE ALONG THE SURFACE BOUNDARY.
00Z DATA SUGGESTS THE GREAT LAKES HIGH WILL GAIN A LITTLE BIT OF
A FOOTHOLD FRI...DECREASING PRECIP CHANCES IN THE AFTERNOON AS
DRIER AIR MOVES IN FROM THE NORTH. HOWEVER...THE HIGHS GRASP WILL
BE TENUOUS AT BEST AT IT WOULD NOT TAKE MUCH TO KEEP THE DEEPER
MOISTURE...AND THUS HIGHER POP...OVER THE FORECAST AREA. SINCE
PREVIOUS FORECAST IS IN AGREEMENT WITH THE MOST CURRENT SOLUTION
WILL CONTINUE THE LOW POP FORECAST FOR FRI WITH SOUTHERN COUNTIES
LIKELY TO HAVE THE BEST SHOT AT STORMS.
TEMPERATURES ABOVE CLIMO THU DROP BACK TO CLIMO FRI(THIS ASSUMES THE
FRONT DOES INDEED PUSH SOUTH OF THE AREA). LOW TEMPERATURES WILL
REMAIN A FEW DEGREES ABOVE CLIMO...HELD UP BY BOUNDARY LAYER
MIXING...LINGERING CLOUD COVER AND LOW LEVEL MOISTURE.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY...PERIOD WILL GENERALLY BE DOMINATED BY DEEP
WEST TO NORTHWEST FLOW AS RIDGING REMAINS IN PLACE OVER THE WESTERN
STATES AND TROUGHING DEVELOPS ALONG THE EAST COAST. INITIALLY WEST
FLOW WILL BE WEAK WITH LITTLE IN THE WAY OF DISTURBANCES ALOFT AND A
FRONT STALLED IN THE AREA. THIS CHANGES MON INTO TUE AS A SHORTWAVE
DROPS SOUTHEAST FROM THE UPPER MID-WEST AND PUSHES A COLD FRONT INTO
THE AREA FOR THE END OF THE PERIOD. AHEAD OF THE FRONT WEAK PIEDMONT
TROUGH AND BERMUDA HIGH SETUP AS THE REMAINS OF THE STALLED FRONT
LIFT NORTH. THE RESULT WILL BE A TYPICAL SUMMER PATTERN ACROSS THE
SOUTHEAST FOR THE WEEKEND. LIMITED SUPPORT ALOFT INTO THE START OF
NEXT WEEK WILL KEEP POP IN THE SLIGHT CHC TO LOW CHC RANGE...WHICH
IS MORE OR LESS CLIMO. FOR THE END OF THE PERIOD AN UPTICK IN POP IS
LIKELY AS THE SHORTWAVE/FRONT COMBO MOVES INTO A WARM/MOIST
ENVIRONMENT. WILL BUMP UP INHERITED POP MON/TUE BUT STILL IN CHC
CATEGORY.
TEMPERATURES WILL STEADILY CLIMB DURING THE PERIOD WITH HIGH PUSHING
INTO THE MID 90S BY THE END OF THE PERIOD. LATEST GFS/ECMWF 850
TEMPS SUGGEST TEMPS APPROACHING UPPER 90S WILL BE POSSIBLE ACROSS
INLAND SC MON. LOWS WILL REMAIN ABOVE CLIMO THROUGH THE
PERIOD...GENERALLY LOWER 70S.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 18Z...VISIBLE SATELLITE IMAGERY SHOWS WIDESPREAD CIRRUS
FILTERING INTO OUR AREA THIS AFTN. VFR WILL PREVAIL TODAY WITH
FEW/SCT CU AND SCT/BKN CIRRUS ACROSS THE CWA. AN UPPER DISTURBANCE
IS APPROACHING FROM THE NORTH...BUT THE LATEST HRRR RUNS INDICATE
THE SHOWERS ASSOCIATED WITH IT SHOULD REMAIN TO OUR NORTH AND EAST.
WILL STILL MENTION VCSH FOR KILM/KLBT AFTER 00Z...BUT PCPN CHANCES
APPEAR MARGINAL ATTM. INCREASING BOUNDARY LAYER WINDS AND MID-LEVEL
CLOUDINESS WILL INHIBIT FOG FORMATION OVERNIGHT. A COLD FRONT WILL
SAG SOUTHWARD TOWARD THE CAROLINAS ON THURSDAY. SCATTERED SHOWERS
AND T-STORMS ARE EXPECTED AHEAD OF THE BOUNDARY...AND SO HAVE ADDED
VCSH BEGINNING AROUND 14-15Z. T-STORMS WILL LIKELY BE MORE PREVALENT
AFTER THE VALID PERIOD...SO DID NOT MENTION THUNDER IN THESE TAFS.
EXTENDED OUTLOOK...EARLY MORNING FOG POSSIBLE FRIDAY AND SATURDAY.
ISOLATED TSRA SUNDAY AND MONDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 2 PM WEDNESDAY...SOUTHWEST FLOW WILL CONTINUE BETWEEN TROUGH
INLAND AND WEAK HIGH PRESSURE OFF SHORE. PERTURBATIONS RIDING
AROUND THE MID TO UPPER RIDGE LOCATED OVER THE CENTRAL CONUS WILL
ACT TO SHARPEN THE TROUGH A BIT OVERNIGHT PRODUCING A SLIGHT RISE IN
WINDS. THE SEA BREEZE THIS AFTERNOON HAS HELPED TO PRODUCE A
GREATER ON SHORE AND SOUTHERLY PUSH WHICH WILL HELP TO PUSH SEAS UP
TO 3 TO 4 FT BY LATE DAY. WINDS WILL VEER TO MORE W-SW TOWARD
MORNING AND THEREFORE EXPECT SEAS THEM TO REMAIN HIGHER OFF
SHORE...WHILE THE NEAR SHORE DROPS SLIGHTLY. OVERALL EXPECT SEAS
TO REMAIN BETWEEN 2 AND 4 FT.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...SOUTHWEST FLOW AHEAD OF A SLOW MOVING COLD
FRONT THU WILL BECOME LIGHT AND VARIABLE THU NIGHT INTO FRI.
EVENTUALLY LIGHT NORTH TO NORTHEAST FLOW WILL DEVELOP DURING FRI AS
THE FRONT PUSHES FARTHER SOUTH OF THE WATERS. HIGH BUILDING IN
BEHIND THE FRONT IS ON THE WEAK SIDE AND LITTLE CHANGE TO THE
GRADIENT IS EXPECTED. SPEEDS START OUT 10 TO 15 KT BUT ONCE THE
FRONT PASSES SPEEDS WILL BE CLOSER TO 10 KT. SEAS 2 TO 4 FT THU
WILL SUBSIDE TO 2 TO 3 FT FRI.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3 AM WEDNESDAY...LIGHT AND VARIABLE FLOW AT THE START OF THE
PERIOD WILL QUICKLY BECOME SOUTH TO SOUTHWEST AS FRONTAL REMAINS
LIFT NORTH AND BERMUDA HIGH BUILDS BACK OVER THE WATERS. GRADIENT
WILL BE WEAK AT FIRST WITH SPEEDS 10 KT OR LESS INTO SAT NIGHT.
DISTANT COLD FRONT WILL LEAD TO A SLIGHT PINCHING OF THE GRADIENT
SUN...INCREASING SPEEDS TO 10 TO 15 KT SUN AND SUN NIGHT. SEAS WILL
RUN 2 TO 3 FT THROUGH THE PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...RGZ
SHORT TERM...III
LONG TERM...III
AVIATION...BJR
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
145 PM EDT WED AUG 28 2013
.SYNOPSIS...
A COLD FRONT WILL SLIDE SOUTH TO THE NORTH CAROLINA/VIRGINIA
BORDER BY THURSDAY MORNING. WEAK HIGH PRESSURE ARRIVES AFTER
THURSDAY. WARM FRONT HEADS NORTH ACROSS OUR AREA BY SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 130 PM EDT WEDNESDAY...
ADJUSTED POPS AND TEMPERATURES WITH LAST RADAR AND OBS TRENDS.
TRIMMED POPS IN THE WEST AND INCREASED IN THE EAST. WITH HEALTHY
CLOUD COVER LOWERED HIGH TEMPERATURES FOR THIS AFTERNOON IN
SEVERAL LOCATIONS.
AS OF 935 AM EDT WEDNESDAY...
A SHORT-WAVE TROUGH OVER THE GREAT LAKES WILL TRAVEL SOUTHEAST TO
OFF THE MID ATLANTIC COAST BY TONIGHT. THIS MORNING 8AM/12Z RNK
SOUNDING DISPLAYED THE JUICY AIRMASS WITH PWATS AROUND 1.5 INCHES
WITH A WEST TO NORTHWEST FLOW. MODIFIED POPS FOR THE NEXT COUPLE
COUPLE OF HOURS TOWARDS THE HRRR WHICH LINED UP FAIRLY WELL WITH
WSR-88D TRENDS. CONTINUED THE HIGHER POPS FOR THIS AFTERNOON IN
THE NORTH AND EAST AS SUPPORT BY ECMWF...GFS AND NAM. SPC HAS
REMOVE THE SEE TEXT OF SEVERE WEATHER FROM OUR AREA WITH THE
EXPECTATION THAT WIDESPREAD CLOUDS WOULD INHIBIT AIRMASS
DESTABILIZATION. QUESTION OF HOW MUCH SUNSHINE WILL DETERMINE IF
WE HAVE ISOLATED SEVERE STORMS THIS AFTERNOON WITH THE THREAT FOR
GUSTY WINDS AND HEAVY RAINS. MORE LATER THIS AFTERNOON...
AS OF 730 AM EDT WEDNESDAY...
BUMPED UP POPS OVER THE NW CWA AS CONVECTION SLIDES SE INTO THE
SRN SHENANDOAH VALLEY. THIS WILL PROGRESS SE INTO THE PIEDMONT
THROUGH THE MORNING WITH EXPECTATIONS OF WEAKENING SOMEWHAT AS IT
CROSSES THE BLUE RIDGE. GIVEN EXTENT OF CLOUD COVER AND SHOWERS
THINKING IS THAT HIGHS TODAY WILL BE A COUPLE MORE DEGREES COOLER
AND LOWER THEM ESPECIALLY FROM THE BLUE RIDGE EAST. THIS MORNINGS
CONVECTION WILL LEAVE BEHIND SOME BOUNDARIES AND NEXT UPSTREAM
WAVE WILL INTERACT WITH THIS TO GENERATE MORE SHOWERS AND STORMS
THIS AFTERNOON. QUESTION REMAINS ON HOW MUCH SUN MAY PEAK
OUT...ESPECIALLY OUT EAST WHERE CLOUDS LOOK TO HANG LONGER. SVR
THREAT STILL APPEARS ISOLATED AND MAY BE MORE OVER THE SOUTHWEST
WHERE BETTER CHANCE OF SEEING SUN OCCURS...ALTHOUGH WILL BE
FURTHER AWAY FROM UPPER FORCING.
PREVIOUS DISCUSSION AT 330 AM...
JUICY AIRMASS WILL BE IN PLACE TODAY AS THETA-E RIDGE AND SFC FRONT
NORTH OF US SHIFTS ESE LATE TONIGHT. MODELS ARE TRACKING A PIECE OF
ENERGY ASSOCIATED WITH CONVECTION OVER THE EASTERN GREAT LAKES/WRN
PA THIS MORNING AND TAKING IT SOUTHEAST ACROSS EASTERN WV/VA INTO NE
NC LATER THIS MORNING INTO THIS EVENING. AT THIS TIME...THE 12Z
ECMWF AS WELL AS THE 00Z LOCAL WRF WERE HANDLING THE LOCATIONS OF
CONVECTION EARLY THOUGH THE ECMWF SEEMS OVERDONE. SEEING THE LATEST
00Z ECMWF THAT JUST ARRIVED KEEPS IT SIMILAR TO THE 12Z BUT A LITTLE
SLOWER IN TIMING. GIVEN WHERE THE THETA-E RIDGE LINES UP AND
MOVEMENT OF THE UPPER WAVE...THINK OUR NRN AND ERN CWA APPEARS TO BE
MORE IN LINE OVERALL TO RECEIVE MORE QPF....THEREFORE HIGHER POPS BY
THIS AFTERNOON. ROUGHLY EAST/NORTHEAST OF A LINE FROM LWB-ROA-DAN.
THE STORM PREDICTION CENTER HIGHLIGHTS US IN A SEE TEXT WITH 5
PERCENT THREAT OF SVR WINDS. MODEST WIND FIELDS AND HIGHER PWATS
FAVOR STRONG WIND GUSTS AND KEPT THE WORDING OF GUSTY WINDS FROM
PREVIOUS FORECAST FOR THE AFTERNOON PERIOD CWA WIDE. LIMITING FACTOR
EXPECTED TO BE CLOUD COVER. THE 00Z CMC/NAM SHOWING THE SOUTHWEST
FROM BLACKSBURG TO MARION SOUTH TO BOONE/WILKESBORO SEEING MORE SUN.
THIS MAY BE THE AREA TO WATCH FOR ISOLATED SVR...WHILE CLUSTER OF
STORMS WITH SHORTWAVE/MCS WILL IMPACT THE NORTHEAST CWA WITH HEAVIER
RAINS...AND LOCALLY SVR WINDS. WILL HIGHLIGHT THREAT OF HEAVY RAIN
AND ISOLATED SVR IN THE HWO.
DURING THE EVENING THE FOCUS SHIFTS MORE OVER THE PIEDMONT AND
COASTAL AREAS OF VA/NC AND WITH FRONT ENTERING THE CWA...MODELS KEEP
THE CONVERGENCE AND SHOWERS LINED UP ACROSS THE EAST/SOUTH EARLY
WITH LESS CHANCE IN THE NORTH AND SOUTHWEST...WITH SOME UPSLOPE
ENHANCEMENT IN SE WV. WITH THE NEW ECMWF SLOWING THINGS DOWN SOME
KEPT HIGHER POPS IN THE EVENING THEN START TO LOWER TO SLIGHT
CHANCE/LOW CHANCE OVERNIGHT.
FOR HIGHS TODAY...THREAT OF MORE CLOUDS AND CONVECTION IN THE
NORTHERN CWA SWAYS ME TO GO A COUPLE/3 DEGREES COOLER THAN MOS WITH
UPPER 70S HSP/LWB TO MID 80S LYH/FVX. OF COURSE IF ANY SUN WERE TO
STAY OUT FOR AN HOUR AND GIVEN DOWNSLOPE AHEAD OF FRONT...90 COULD
BE POSSIBLE AT LYH/FVX...BUT MODEL CLOUD FIELDS LEAD ME TO BELIEVE
COOLER IS MORE LIKELY. NOW THE FURTHER SOUTHWEST WE GO THE WARMER IT
WILL BE AS SUN WILL BE MIXED IN AT TIMES. STILL BEING THE POTENTIAL
FOR SOME CLOUDS FROM UPSTREAM CONVECTION SETTLED CLOSE TO MOS
GUIDANCE WITH LOWER TO MID 80S SOUTHWEST VA MOUNTAINS/VALLEYS TO MID
TO NEAR 90 ROANOKE/DANVILLE/NW NC PIEDMONT/FOOTHILLS.
LITTLE CHANGE IN AIRMASS TONIGHT SO LOWS WILL STAY WARM FROM THE MID
60S ACROSS THE ALLEGHANY HIGHLANDS/GREENBRIER VALLEY TO UPPER 60S TO
LOWER 70S ELSEWHERE.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
AS OF 345 AM EDT WEDNESDAY...
ALTHOUGH WEAK BOUNDARY WILL BE JUST TO OUR SOUTH THURSDAY...GOOD
SURFACE WIND CONVERGENCE ALONG THE SOUTHERN BLUE RIDGE SHOULD FORCE
SHOWERS AND THUNDERSTORMS FOR THE AFTERNOON. HOWEVER...MOISTURE
LOOKS RATHER SCANT IN THE MID LEVELS...SO THIS MAY BE A LIMITING
FACTOR. H85 TEMPS WILL ONLY BE A FEW DEGREES COOLER BEHIND THIS SO
CALLED FRONT WITH SURFACE DEWPOINTS STAYING IN THE SOUPY MID 60S.
LESS MOISTURE ALOFT IS WHAT REALLY KNOCKS DOWN THE PWATS IN
COMPARISON TO WEDNESDAY. WEAK HIGH PRESSURE WILL STRETCH FROM THE
MID ATLANTIC AND OFF THE COAST ON FRIDAY. WITH MORE OF AN EASTERLY
COMPONENT...INSTABILITY IS REDUCED...TEMPS ARE COOLER...WITH THIS
BEING THE DRIEST DAY OF THE SHORT TERM. HIGHEST POPS WILL BE PLACED
OVER NW NC. AS THE SURFACE HIGH MOVES OF THE COAST SATURDAY...WINDS
VEER TO MORE OF A SOUTHERLY DIRECTION. THIS ALLOWS MORE MOISTURE TO
RETURN BACK NORTH AND COMBINE WITH A DEEPENING TROUGH ACROSS THE
GREAT LAKES AND OHIO VALLEY TO PRODUCE MORE WIDESPREAD STORMS THAN
FRIDAY...WITH THE MOST ALONG THE BLUE RIDGE. WITH PWATS ELEVATED
ONCE AGAIN AND WEAK FLOW...THERE MAY BE THE POTENTIAL FOR SOME
BACKBUILDING HEAVY RAINERS AND WATER PROBLEMS. BASED ON THE CLOUDS
AND POTENTIAL FOR STORMS...DID STAY BELOW GUIDANCE THURSDAY AND
SATURDAY FOR HIGHS.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 115 PM EDT TUESDAY...
DIFFERENT MODEL GUIDANCE DURING THIS PORTION OF THE FORECAST PACKAGE
VARIES OF THE SPECIFICS...BUT IS FAIRLY CONSISTENT ON THE
GENERALITIES. GENERALLY SPEAKING...THE NORTHEAST U.S. IS EXPECTED TO
HAVE SOME DEGREE OF TROUGHINESS OVER IT DURING THIS PORTION OF THE
FORECAST...WITH NORTHWEST FLOW ALOFT OVER OUR REGION. CLOSER TO THE
SURFACE...HIGH PRESSURE WILL TAKE UP RESIDENCE ALONG THE EAST
COAST...AND PREVAILING FLOW AROUND IT WILL HELP DEVELOP FLOW FROM
THE SOUTH THAT WILL DIRECT MOISTURE INTO OUR REGION. DURING THE
MONDAY INTO TUESDAY TIME FRAME...A NORTHERN STREAM TROUGH WILL HELP
DEEPEN...AND THEN GRADUALLY EJECT THE EAST COAST TROUGH INTO THE
WESTERN ATLANTIC...AND UPPER LEVEL RIDGING WILL START NOSING INTO
THE AREA FROM THE MID-WEST.
THE ABOVE POINTS TOWARD THE FOLLOWING SCENARIO. MAINLY AFTERNOON AND
EARLY EVENING SCATTERED SHOWERS AND STORMS ARE EXPECTED SUNDAY
TRIGGERED PRIMARILY BE DAYTIME HEATING. HOWEVER...AND THIS IS
WHERE THE SPECIFICS GET TRICKY...UPSTREAM SHORTWAVE TROUGHS MAY
RIDE SOUTHEAST WITHIN THE NORTHWEST FLOW ALOFT AND ADD AN
INCREASED ELEMENT OF UPPER LEVEL DYNAMICS TO THE FORECAST PICTURE
AND THUS BETTER COVERAGE. SIMILARITY...THIS SAME FLOW MAY HELP
ADVECT AN UPSTREAM THUNDERSTORM COMPLEX INTO THE REGION...AND THIS
TOO WOULD ALLOW FOR BETTER COVERAGE OF SHOWERS AND
STORMS...ESPECIALLY ACROSS THE WESTERN PORTION OF THE AREA.
PINPOINTING THESE FEATURES IS WHERE MODEL GUIDANCE VARIES TOO
GREATLY TO TRY TO INCORPORATE EITHER OF THESE SCENARIOS INTO THE
FORECAST AT THIS TIME.
MONDAY INTO TUESDAY...GUIDANCE ALSO VARIES AS TO THE TIMING AND
TRACK OF THE NORTHERN STREAM SYSTEM AND THUS THE IMPACT AND TIMING
OF ITS ASSOCIATED SURFACE COLD FRONT. WE WILL OFFER A SOLUTION
COMPARABLE TO WHAT IS PUT FORTH BY WPC WITH MONDAY AFTERNOON AND
EVENING LOOKING THE MOST PROMISING CURRENTLY. WOULD NOT BE SURPRISED
AS WE DRAW NEARER TO THIS TIME FRAME THAT THE FRONT ENDS UP ARRIVING
MONDAY NIGHT INTO TUESDAY MORNING...OR LATER.
TEMPERATURES THROUGH THIS TIME FRAME SHOULD SLOWLY INCREASE THROUGH
MONDAY AHEAD OF THE COLD FRONT...AND THEN BE COOLER AND LESS HUMID
ON TUESDAY WITH OUR CURRENT FORECAST TIMING OF THE COLD FRONT.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 130 PM EDT WEDNESDAY...
AREAS OF MVFR LOW CLOUDS...FOG AND HAZE PRESIST THIS AFTERNOON
INTO THIS EVENING AS AN AREA OF SHOWERS MOVES SOUTHEAST OUT OF
CWA THIS AFTERNOON.
ANOTHER SHORTWAVE WILL DROP SOUTH ACROSS THE REGION INTO TONIGHT.
THIS SHOULD RESULT IN ADDITIONAL SHOWERS AND THUNDERSTORMS
DEVELOPING AND TRAVELING SOUTHEAST ACROSS THE REGION INTO THE
EVENING HOURS.
BY TONIGHT...THE MODELS TRACK THE PRECIPITATION EAST AND OFFSHORE
OVERNIGHT. CLOUDS MAY LINGER OVERNIGHT IN THE EAST BUT ENOUGH
CLEARING IN THE WEST COULD LEAD TO AREAS OF FOG ESPECAILLY AT
LWB/BLF AND BCB.
SPOTTY SHOWERS AND THUNDERSTORMS WILL REMAIN IN THE FORECAST FOR
THURSDAY AS WEAK DISTURBANCES RIDE ACROSS THE AREA FROM THE GREAT
LAKES OVERTOP NORTHEASTERLY FLOW NEAR THE SURFACE AS HIGH
PRESSURE BUILDS IN. EXPECT A RETURN TO OVERALL VFR CONDITIONS UNDER
HIGH PRESSURE...WITH ONLY ISOLATED SHOWERS AT BEST FRIDAY AND
SATURDAY. OTHERWISE SOME PATCHY FOG LIKELY DURING THE OVERNIGHTS
INTO SATURDAY...WITH LATE NIGHT/EARLY MORNING MVFR/IFR CONDITIONS
POSSIBLE ESPECAILLY AT THE VALLEY LOCATIONS.
&&
.EQUIPMENT...
AS OF 100 PM EDT WEDNESDAY...
THE TEMPERATURE/DEWPOINT AT THE ROANOKE ASOS (ROA) WILL BE
AUGMENTED BY OBSERVERS FROM AN AUXILIARY UNIT UNTIL FURTHER
NOTICE. EL TECH WORKING ON REPAIRS AT THE ROANOKE AIRPORT THIS
AFTERNOON...TIME OF RESTORATION OF THE PRIMARY EQUIPMENT MAY BE
LATER THIS AFTERNOON.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WP/KK
NEAR TERM...KK/WP
SHORT TERM...KM
LONG TERM...DS
AVIATION...KK/WP
EQUIPMENT...AMS/KK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
321 PM CDT WED AUG 28 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 321 PM CDT WED AUG 28 2013
THE MAIN FOCUS TONIGHT INTO TOMORROW IS WITH THE CHANCES OF
PRECIPITATION AND WHETHER ANY FOG WILL DEVELOP OVERNIGHT AGAIN.
THE UPPER LEVEL FLOW CONTINUES TO BE SHAPED BY BROAD RIDGING THAT
IS CENTERED OVER THE PLAINS AND EXTENDS FROM THE SOUTHEASTERN US
TO THE SOUTHWESTERN US. ANY PRECIPITATION HAS COME ALONG THE NORTHERN
PERIPHERY OF THIS RIDGE AS MID LEVEL SHORT WAVE TROUGHS TRACK
ALONG THE RIM. THERE CURRENTLY ARE A PAIR OF SHORT WAVE TROUGHS
THAT WILL NEED MONITORING INTO TOMORROW...ONE WEAK ONE IN THE
DAKOTAS/WESTERN MINNESOTA AND ANOTHER RUNNING INTO MONTANA. AT THE
SURFACE...A COLD FRONT HAS STALLED OUT ACROSS CENTRAL IOWA WITH
RIDGING ACROSS THE NORTHERN GREAT LAKES. DEW POINTS HAVE REALLY
POOLED ALONG THE NORTHERN SIDE OF THIS FRONT WITH MID/UPPER 70S
ANALYZED FROM CENTRAL ILLINOIS THROUGH EASTERN/NORTHERN IOWA.
EARLIER STRATUS HAS ALSO BECOME MORE MIXED AS THE DAY HAS GONE ON
TODAY...WHICH HAS LEAD TO SOME QUICK WARM UPS AS WELL.
GOING INTO TONIGHT...THE FIRST SHORTWAVE IN THE DAKOTAS/MINNESOTA
WILL PROPAGATE TO THE EAST AND WILL HELP TO LIFT THE FRONT BACK TO
THE NORTH AS A WARM FRONT ACROSS SOUTHERN MINNESOTA. THE 18.12Z
NAM/GFS AND 18.18Z RAP SHOWS THE POOL OF HIGHEST 0-3KM MUCAPE
LIFTING NORTH AS WELL IN MINNESOTA AND BECOMING ORIENTED MORE
NORTH TO SOUTH FROM CENTRAL MINNESOTA TO EASTERN IOWA OVERNIGHT.
THE BEST LOW LEVEL MOISTURE TRANSPORT APPEARS TO BE IN CENTRAL
MINNESOTA AS WELL WHERE THE STRONGER PUSH/CONVERGENCE IS FROM THE
SOUTH. HAVE KEPT SOME LOW CHANCES OF SHOWERS/STORMS OVERNIGHT IN
PORTIONS OF SOUTHEAST MINNESOTA/NORTHEAST IOWA TO ACCOUNT FOR
THIS...BUT CONFIDENCE IS NOT OVERLY HIGH THAT THE FORCING WILL BE
ENOUGH TO PRODUCE SOME CONVECTION.
THE HIGHER CHANCES FOR PRECIPITATION WILL COME ON THURSDAY AS THE
SECOND MID LEVEL SHORT WAVE TROUGH PROPAGATES EAST FROM MONTANA
THROUGH THE DAKOTAS ON TOWARD THE UPPER GREAT LAKES. IT APPEARS
THAT AN MCS WILL DEVELOP OVER THE DAKOTAS FROM THIS FEATURE AND
TRACK TO THE EAST INTO MINNESOTA TOMORROW MORNING. AS THE
SHORTWAVE ENTERS MINNESOTA/NORTHERN WISCONSIN LATE TOMORROW
MORNING/AFTERNOON...CONVECTION MAY DEVELOP ALONG THE WARM FRONT
WHICH WILL BE LIFTING TO THE NORTH AS A LOW MOVES INTO CENTRAL
MINNESOTA. WITH THE HIGH INSTABILITY ON THE ORDER OF 2000-4000
J/KG AND DECENT SHEAR...CAN NOT RULE OUT SOME SEVERE WEATHER
ACROSS NORTHERN WISCONSIN THE AFTERNOON HOURS WITH LARGE
HAIL/DAMAGING WINDS THE MAIN THREATS. NORTHERN WISCONSIN IS ALSO
THE LOCATION OF THE HIGHEST PRECIPITATION CHANCES AS THIS TROUGH
MOVES THROUGH GOING INTO THURSDAY NIGHT.
WITH LIGHT WINDS AND HIGH AMOUNTS OF LOW LEVEL MOISTURE STILL IN
THE REGION...CAN NOT RULE OUT SOME FOG TONIGHT...PARTICULARLY IN
WESTERN WISCONSIN WHICH WILL BE CLOSER TO THE HIGH AND FURTHER
FROM ANY CLOUD COVER.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 321 PM CDT WED AUG 28 2013
THE COMPLEX WILL MOVE THROUGH ON THURSDAY NIGHT WITH A COLD FRONT
DROPPING DOWN ACROSS THE REGION ON FRIDAY. THE 28.12Z NAM/GFS
FORECAST SOUNDINGS DIFFER ON THE AMOUNT OF CAPPING THAT WILL BE IN
PLACE AHEAD OF THIS FRONT WITH THE NAM SHOWING MORE OF IT AND THE
GFS LESS. THUS...THE NAM IS MAINLY DRY WITH THE FROPA WHILE THE
GFS PRODUCES SOME QPF. KEPT SOME PRECIPITATION CHANCES IN THERE
FOR NOW...MAINLY IN WESTERN WISCONSIN.
TEMPERATURES WARM UP AHEAD OF THIS FRONT WITH HIGHS GOING BACK
INTO THE 90S ACROSS MUCH OF NORTHEAST IOWA AND FAR SOUTHWEST
WISCONSIN. WITH HEAT INDICES AROUND 100F IN THE AFTERNOON...MAY
HAVE TO DO A HEAT ADVISORY FOR THIS REGION.
BEYOND THIS...A BIG PATTERN CHANGE IS ON THE WAY FOR SUNDAY AS A
MID LEVEL TROUGH DIGS DOWN FROM CANADA AND BRINGS A MUCH COOLER
AIR MASS DOWN INTO THE REGION. 850MB TEMPERATURES...WHICH
GENERALLY HAVE BEEN IN THE +15C TO +25C RANGE THE PAST WEEK...WILL
DROP TO ABOUT +7C SUNDAY NIGHT AFTER THE COLD FRONT SWINGS
THROUGH. WHILE STORMS LOOK POSSIBLE WITH THE COLD FRONT COMING
THROUGH...THE TIME OF THE DAY DOES NOT LOOK FAVORABLE FOR SEEING
SEVERE WEATHER AS THE FRONT WILL LIKELY COME THROUGH IN THE
MORNING BEFORE ANY HIGH INSTABILITY CAN BUILD. HIGH PRESSURE THEN
SETTLES IN FOR THE EARLY PART OF NEXT WEEK WITH MUCH COOLER AND
SEASONABLE TEMPERATURES ON TAP.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1220 PM CDT WED AUG 28 2013
EASTERLY WINDS IN THE SFC-850MB LAYER CONTINUE TO ADVECT MVFR
STRATUS DECKS WESTWARD ACROSS THE TAF SITES EARLY THIS AFTERNOON.
THESE CLOUDS/MOISTURE STUCK UNDER A MDT/STRONG INVERSION NEAR
900MB...MAKING THE CLOUDS MUCH MORE PERSISTENT THAN EARLIER THOUGHT.
WITH DIURNAL WARMING/MIXING...THE CLOUD DECK WILL SLOWLY BECOME
BKN-SCT THRU THE AFTERNOON. WITH A FRONTAL BOUNDARY JUST SOUTH OF
THE AREA AND THE MOISTURE TRAPPED UNDER THE INVERSION...SOME MVFR
CLOUDS LOOKING TO PERSIST WELL INTO TONIGHT AND LIKELY INTO THU.
DEBRIS CLOUDS FROM CONVECTION TO THE WEST TO SPREAD ACROSS THE AREA
TONIGHT. WITH THE HUMID LOW LEVEL AIRMASS AND GENERALLY LIGHT
WINDS...THESE HIGHER LEVEL CLOUDS SHOULD HELP KEEP FOG FROM BECOMING
WIDESPREAD AND DENSE LATE TONIGHT/EARLY THU MORNING. HOWEVER...
CONTINUED/ADDED MVFR VSBYS IN BR AT BOTH KRST/KLSE IN THE 09Z-1430Z
TIME-FRAME. THIS WILL HAVE TO BE WATCHED...IF HIGHER LEVEL CLOUDS
END UP MORE SCT OR THIN...ALLOWING FOR MORE RADIATIONAL COOLING...
FR VSBYS IN BR/FG COULD PREVAIL ACROSS THE AREA IN THE 09-14Z
PERIOD. SHRA/TSRA CHANCES LATER TONIGHT/THU TOO SMALL TO MENTION IN
TAFS FOR NOW.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1220 PM CDT WED AUG 28 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM CDT WED AUG 28 2013
..CURRENTLY AS OF 08Z..
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED DEEP TROUGHING
JUST OFF THE U.S. WEST COAST WHILE STRONG SUBTROPICAL RIDGING
CONTINUES TO DOMINATE THE CENTRAL PLAINS. A WEAK RIDGE AXIS EXTENDED
FROM THE SUBTROPICAL RIDGE NORTH INTO THE DAKOTAS. MONSOONAL
MOISTURE AND SHORTWAVES CONTINUE TO ROTATE AROUND THE SUBTROPICAL
RIDGE...FROM ARIZONA INTO THE DAKOTAS AND SOUTHEAST THROUGH THE
FORECAST AREA. REGARDING THE MOISTURE...RAP PRECIPITABLE WATER
ANALYSIS SHOWED VALUES OF 1.5-2 INCHES EXTENDING FROM THE DAKOTAS
SOUTHEASTWARD THROUGH MUCH OF THE FORECAST AREA. EARLY THIS MORNING
ALL MONSOONAL SHORTWAVES WERE EITHER TO THE EAST OR WEST OF THE
FORECAST AREA...RESULTING IN DRY CONDITIONS. AT THE SURFACE A WEAK
COLD FRONT WAS SLOWLY DROPPING SOUTH THROUGH THE FORECAST AREA...NOW
STRETCHED ACROSS NORTHERN IOWA AND FAR SOUTHERN WI. THE FRONT HAS
HAD A HARD TIME SCOURING OUT THE SURFACE MOISTURE WITH DEWPOINTS
GENERALLY IN THE LOW 70S ACROSS THE AREA. THE COOLING WITH THE FRONT
HAS BEEN SHALLOW...EVIDENCED ON THE 00Z GRB SOUNDING WITH 925MB
TEMPS OF 22C COMPARED TO 29C AT DVN. SURFACE TEMPERATURES HAVE
FALLEN OFF INTO THE LOW TO MID 70S NORTH OF THE FRONT...AND MID TO
UPPER 70S TO THE SOUTH. THE COOLING INTERACTING WITH THE LINGERING
MOISTURE HAS CAUSED BOTH MIST AND LOW STRATUS TO FORM. VISIBILITIES
ARE LOWEST OVER NORTH CENTRAL WI DUE TO RECENT RAINS. 11-3.9 UM
IMAGERY SHOWED THE BULK OF THE STRATUS ACROSS CENTRAL AND EASTERN
WI.
..HAZARDS..
1. HEAT. NORTH OF I-90...HEAT INDICES ARE FORECAST BETWEEN
90-95...THEREFORE FEEL CONFIDENT NO ADDITIONAL HEAT ADVISORY IS
NEEDED. SOUTH OF I-90 HEAT INDICES ARE EXPECTED TO TOP OUT AROUND
95 TO AT MOST 100. GIVEN THAT THESE ARE BELOW ADVISORY CRITERIA
AND 5 TO 10 DEGREES LOWER THAN THE PAST FEW DAYS...HAVE DECLINED
TO ISSUE A HEAT ADVISORY HERE AS WELL.
2. DENSE FOG ACROSS TAYLOR AND CLARK COUNTIES...WHICH SHOULD
DISSIPATE BETWEEN 9-10 AM.
..SYNOPTIC OVERVIEW..
VERY LITTLE CHANGE IS FORECAST BY MODELS IN THE UPPER AIR PATTERN
DURING THE NEXT 24 HOURS. IF ANYTHING...THE WEAK RIDGE AXIS OVER THE
DAKOTAS GETS FLATTENED OUT AND PUSHED EAST...IN RESPONSE TO A
STRONGER MONSOONAL SHORTWAVE LIFTING INTO NORTH DAKOTA BY 12Z
THURSDAY. AT THE SURFACE...THE WEAK COLD FRONT OVER THE SOUTHERN
PORTION OF THE FORECAST AREA LOOKS TO CONTINUE TO SLOWLY DRIFT
SOUTH...PROGGED TO BISECT IOWA NORTHWEST TO SOUTHEAST BY 00Z. IN
ITS WAKE...HIGH PRESSURE BUILDS IN OVER WISCONSIN. THE FRONT MAY
START TO LIFT BACK TOWARDS THE AREA LATE TONIGHT IN RESPONSE TO WARM
ADVECTION AHEAD OF THE SHORTWAVE MOVING INTO NORTH DAKOTA.
..DETAILS..
SOLAR HEATING WILL HELP TO GRADUALLY IMPROVE VISIBILITIES AND MIX
OUT THE LOW STRATUS AIMING AT SOUTHWEST WI THIS MORNING. BY 18Z ALL
FOG AND STRATUS SHOULD BE GONE. OTHERWISE...DRY ADVECTION IN THE LOW
TO MID LEVELS OF THE ATMOSPHERE ACCOMPANYING THE SURFACE HIGH...
COMBINED WITH CAPPING BY A WARM LAYER AT 750MB...WILL HELP TO KEEP
CONDITIONS DRY TODAY. THE 28.00Z GFS DOES TRY TO CONVECT ACROSS
NORTHEAST IOWA NEAR THE FRONT THIS AFTERNOON...BUT IS THE ONLY MODEL
TO DO SO. HAVE KEPT THE FORECAST DRY DUE TO LIMITED CONVERGENCE ON
THE FRONT AND THE CAPPING POTENTIAL...ALONG WITH ALL OTHER MODELS
SUGGESTING DRY CONDITIONS ON THE FRONT. TEMPERATURES TODAY WILL BE
ABOUT 5 DEGREES COOLER WITH 925MB READINGS DOWN TO 24-26C VERSUS THE
28-30C THAT OCCURRED YESTERDAY. SURFACE DEWPOINTS...ON THE OTHER
HAND...ARE STILL GOING TO BE STUCK IN THE LOW TO PERHAPS MID 70S
SOUTH OF I-90. THUS HEAT INDICES IN THIS AREA OF 95 TO AT MOST 100
ARE EXPECTED. TO THE NORTH...DEWPOINTS SHOULD MIX/FALL INTO THE
60S...KEEPING HEAT INDICES MORE IN THE 90-95 RANGE.
FOR TONIGHT...GOOD MODEL AGREEMENT EXISTS ON THE WARM ADVECTION
SCENARIO. THE BIGGEST ISSUES ARE IF AND WHEN CONVECTION CAN FIRE
FROM THE WARM ADVECTION. HERE AGAIN...THE 28.00Z GFS IS QUICKEST AND
MOST EXPANSIVE...SUGGESTING CONVECTION WEST OF THE MS RIVER ALL
NIGHT. ALL OTHER GUIDANCE WAITS UNTIL AFTER MIDNIGHT...AND IN THE
CASE OF THE 28.00Z REGIONAL CANADIAN AS WELL AS THE 28.00Z NAM...
THEY NEVER FIRE ANY CONVECTION. FOR NOW HAVE LEANED MORE TOWARDS THE
CONSISTENT ECMWF AS IT ALSO HAS DONE BEST WITH CONVECTION AS OF
LATE. THE MODEL SUGGESTS ELEVATED CONVECTION FIRING AFTER MIDNIGHT
FROM GRAND FORKS DOWN TO AROUND AUSTIN. GIVEN THAT THIS CONVECTION
WILL OCCUR IN THE 1.5-2 INCH PRECIPITABLE WATER STREAM...LOCALLY
HEAVY RAIN COULD OCCUR WITH THE STORMS. ANOTHER MILD TO WARM NIGHT
EXPECTED AGAIN...WARMEST WEST OF THE MS RIVER WITH MORE CLOUDS AND
HIGHER DEWPOINTS.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 334 AM CDT WED AUG 28 2013
..HAZARDS..
1. HEAT. POTENTIAL FOR ANOTHER HEAT ADVISORY COME FRIDAY...
ESPECIALLY ACROSS NORTHEAST IOWA. SATURDAY ALSO HAS A POTENTIAL NEED
FOR A HEAT ADVISORY IF WARM AIR PROGGED THEN ADVECTS IN FASTER.
2. STORMS. THOSE STORMS THAT OCCUR THURSDAY NIGHT ALONG/NORTHEAST OF
I-94 COULD POSE A HEAVY RAIN CONCERN WITH A SMALL RISK OF DAMAGING
WINDS.
..SYNOPTIC OVERVIEW..
28.00Z MODEL GUIDANCE REMAINS IN GOOD AGREEMENT WITH YESTERDAYS
MODEL RUNS OF SHOWING THE SUBTROPICAL RIDGE RETROGRADING INTO THE
FOUR CORNERS REGION THIS WEEKEND. THIS RESULTS IN A GRADUAL FALL OF
500MB HEIGHTS OVER THE FORECAST AREA. ADDITIONALLY...THE BULK OF THE
DEEP TROUGH JUST OFF THE U.S. WEST COAST IS PROGGED TO EJECT OUT
ACROSS SOUTHERN CANADA THIS FRIDAY AND SATURDAY. MODELS HAVE
STRUGGLED A BIT ON THE DEGREE OF AMPLIFICATION WITH THIS TROUGH AS
IT APPROACHES NORTHERN ONTARIO AND LAKE SUPERIOR SUNDAY MORNING...
BUT THEY APPEAR NOW TO HAVE SETTLED DOWN. ALL INDICATIONS ARE THAT
AFTER IT PASSES LAKE SUPERIOR...THE TROUGH WILL THEN DIG INTO THE
EASTERN GREAT LAKES MONDAY AND TUESDAY...WHILE UPPER RIDGING BUILDS
BACK UP OVER THE NORTHERN PLAINS.
..DETAILS..
THE SHORTWAVE OVER NORTH DAKOTA AT 12Z THURSDAY LOOKS TO TRACK
ACROSS NORTHERN MN ON THURSDAY AND INTO UPPER MI THURSDAY NIGHT.
GIVEN THIS TRACK...THE BULK OF THE DYNAMIC FORCING WILL STAY NORTH
OF THE FORECAST AREA...THOUGH TAYLOR AND CLARK COUNTIES COULD GET
BRUSHED. MORE IMPORTANTLY ABOUT THIS SHORTWAVE IS THE ISENTROPIC
LIFT AND LOW LEVEL MOISTURE TRANSPORT OCCURRING WITH IT AND TO ITS
SOUTH. ON THURSDAY...THIS ISENTROPIC LIFT CENTERED ON THE 310-315K
SURFACES AND LOW LEVEL MOISTURE TRANSPORT SLOWLY MARCHES ACROSS THE
FORECAST AREA...GETTING HUNG UP ACROSS WISCONSIN AT 00Z FRIDAY. THE
STRONGEST LIFT/MOISTURE TRANSPORT IS SITUATED NORTH OF THE FORECAST
AREA...BUT STILL WARRANTS 20-40 PERCENT CHANCES. CHANCES INCREASE
ACROSS WISCONSIN THURSDAY NIGHT...ESPECIALLY ALONG/NORTHEAST OF
I-94...AS THE MOISTURE TRANSPORT INCREASES WITH THE NOCTURNAL
INCREASE OF THE LOW LEVEL JET. STRONG MODEL CONSENSUS FOR CONVECTION
THUS 60-70 PERCENT CHANCES SEEM REASONABLE. ALONG AND WEST OF THE MS
RIVER THURSDAY NIGHT...THERE MAY BE VERY LITTLE TO ANY ACTIVITY.
TEMPERATURES ON THURSDAY DEPEND ON HOW MUCH SUN WE SEE...AND WITH
925MB READINGS RANGING FROM 22C EAST TO 27C WEST...THERE COULD BE A
WIDE SPREAD IN HIGHS. FOLLOWED A GUIDANCE CONSENSUS FOR NOW
RESULTING HIGHS IN THE 80S...WARMEST WEST AND IN RIVER VALLEYS.
GUIDANCE CONSENSUS ALSO FOLLOWED FOR LOWS THURSDAY NIGHT.
FOR FRIDAY INTO FRIDAY NIGHT...MODELS CONTINUE TO SHOW A SECOND
SHORTWAVE DROPPING SOUTHEAST OUT OF CENTRAL MN THROUGH THE FORECAST
AREA ON FRIDAY. WITH THIS SHORTWAVE COMING THROUGH AT PEAK HEATING
AND PLENTY OF MOISTURE IN PLACE...NOTED BY PRECIPITABLE WATER VALUES
PROGGED BETWEEN 1.5-1.75 INCHES...NEED TO HAVE SOME CHANCES OF
SHOWERS AND THUNDERSTORMS. MODELS VARY A BIT ON THE STRENGTH OF THIS
SHORTWAVE THUS CHANCES ARE ONLY IN THE 20-30 RANGE. WE MIGHT BE ABLE
TO SQUEEZE IN FRIDAY NIGHT AS DRY PER 28.00Z ECMWF/NAM...HOWEVER...
THE 28.00Z GFS SHOWS WARM AIR ADVECTION RETURNING AHEAD OF A COLD
FRONT MARCHING ACROSS THE DAKOTAS. TO ACCOUNT FOR THE GFS
SCENARIO...HAVE KEPT 20-30 PERCENT CHANCES GOING. FRIDAY HIGHS ARE
ALSO TRICKY AS THEY DEPEND BOTH ON STRENGTH AND TIMING OF THE
SHORTWAVE. THE ECMWF/GFS/CANADIAN ALL SHOW AN INFLUX OF 28-30C 925MB
AIR INTO THE FORECAST AREA...WHICH COULD SUPPORT HIGHS IN THE MID
90S LIKE WE HAVE SEEN. BEST PROBABILITY OF THIS APPEARS TO BE IN
NORTHEAST IOWA WHICH THEN WOULD HAVE THE BEST CHANCE OF NEEDING A
HEAT ADVISORY. THE REST OF THE AREA IS A LITTLE MORE UNCERTAIN.
FOR SATURDAY AND BEYOND...
FOCUS IS ALL ON THAT TROUGH COMING ACROSS SOUTHERN CANADA. MODELS
ARE IN PRETTY GOOD AGREEMENT SHOWING THE COLD FRONT CROSSING THE
AREA DURING THE DAY SUNDAY. AHEAD OF THE FRONT...THERE WILL BE
ANOTHER SURGE OF WARM AIR COMING INTO THE AREA FOR SATURDAY. IF THE
GFS IS CORRECT WITH 925MB TEMPS OF 29-31C...A HEAT ADVISORY WOULD BE
REQUIRED...WHILE THE ECMWF IS MORE SCALED BACK WITH 925MB TEMPS OF
25-28C. FOR NOW THE HIGH TEMPERATURE FORECAST SPLITS THE DIFFERENCE
BETWEEN THESE MODELS. COULD SEE SOME WARM ADVECTION SHOWERS/STORMS
TOO...RIGHT THROUGH SATURDAY NIGHT. ADDITIONALLY...THERE COULD BE
SOME SHOWERS/STORMS THAT ARE FRONTOGENETICALLY DRIVEN AROUND THE
COLD FRONT ON SUNDAY. THEREFORE...20-40 PERCENT CHANCES PER
CONSENSUS ARE IN THE FORECAST. AFTER SUNDAY...DRY CONDITIONS WILL
PREVAIL AS HIGH PRESSURE BUILDS IN AND PERSISTS OVER THE AREA.
TEMPERATURES SUNDAY AND BEYOND ARE TRICKY AS THE 00Z AND 12Z ECMWF
RUNS ALTERNATE ON THE STRENGTH OF COLD ADVECTION. FOR NOW STUCK WITH
A MODEL CONSENSUS FOR HIGHS AND LOWS SUNDAY THROUGH TUESDAY...BUT IF
THE 00Z ECMWF RUNS ARE CORRECT...TEMPERATURES MAY NEED TO BE LOWERED
ANOTHER 5 DEGREES OR SO.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1220 PM CDT WED AUG 28 2013
EASTERLY WINDS IN THE SFC-850MB LAYER CONTINUE TO ADVECT MVFR
STRATUS DECKS WESTWARD ACROSS THE TAF SITES EARLY THIS AFTERNOON.
THESE CLOUDS/MOISTURE STUCK UNDER A MDT/STRONG INVERSION NEAR
900MB...MAKING THE CLOUDS MUCH MORE PERSISTENT THAN EARLIER THOUGHT.
WITH DIURNAL WARMING/MIXING...THE CLOUD DECK WILL SLOWLY BECOME
BKN-SCT THRU THE AFTERNOON. WITH A FRONTAL BOUNDARY JUST SOUTH OF
THE AREA AND THE MOISTURE TRAPPED UNDER THE INVERSION...SOME MVFR
CLOUDS LOOKING TO PERSIST WELL INTO TONIGHT AND LIKELY INTO THU.
DEBRIS CLOUDS FROM CONVECTION TO THE WEST TO SPREAD ACROSS THE AREA
TONIGHT. WITH THE HUMID LOW LEVEL AIRMASS AND GENERALLY LIGHT
WINDS...THESE HIGHER LEVEL CLOUDS SHOULD HELP KEEP FOG FROM BECOMING
WIDESPREAD AND DENSE LATE TONIGHT/EARLY THU MORNING. HOWEVER...
CONTINUED/ADDED MVFR VSBYS IN BR AT BOTH KRST/KLSE IN THE 09Z-1430Z
TIME-FRAME. THIS WILL HAVE TO BE WATCHED...IF HIGHER LEVEL CLOUDS
END UP MORE SCT OR THIN...ALLOWING FOR MORE RADIATIONAL COOLING...
FR VSBYS IN BR/FG COULD PREVAIL ACROSS THE AREA IN THE 09-14Z
PERIOD. SHRA/TSRA CHANCES LATER TONIGHT/THU TOO SMALL TO MENTION IN
TAFS FOR NOW.
&&
.CLIMATE...
ISSUED AT 334 AM CDT WED AUG 28 2013
THE FOLLOWING ARE RECORD HIGHS FOR LA CROSSE AND ROCHESTER
INTO LABOR DAY WEEKEND...GIVEN STILL MORE HEAT FORECAST. FOR MORE
CLIMATE INFORMATION...SEE OUR WEBSITE AND THE TOP NEWS STORY ON
THE RECENT HEAT.
LA CROSSE ROCHESTER
--------- ---------
WED 8/28 97/1955 96/1955
THU 8/29 95/1966 92/2012
FRI 8/30 97/2012 96/1941
SAT 8/31 95/1953 93/1960
SUN 9/1 98/1913 94/1937
MON 9/2 98/1937 94/1929
NORMAL HIGH TEMPERATURES THROUGH THIS PERIOD ARE 78-80 AT LA CROSSE
AND 76-78 AT ROCHESTER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM....AJ
AVIATION.....RRS
CLIMATE......AJ
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1210 PM CDT WED AUG 28 2013
UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE
.SHORT TERM...TODAY...TONIGHT...AND THURSDAY
ISSUED AT 405 AM CDT WED AUG 28 2013
FORECAST CONCERNS ON CLOUDS AND FOG THIS MORNING. MODELS FAIRLY
SIMILAR WITH FRONT SOUTH OF CWA. NORTHEAST WINDS AT SFC AND ALOFT BEHIND
FRONT...HAS LED TO WIDESPREAD LOW CLOUDS OFF LAKES TO MOVE OVER
MUCH OF CWA. LESS CLOUDS OVER NORTH CENTRAL HAS LED TO WIDESPREAD
DENSE FOG WITH VISIBILITIES FLUCTUATING AROUND 1/4 MILE. WILL
COVER WITH ADVISORY THROUGH 8AM. GUIDANCE SUGGESTS LOW CLOUDS TO
STICK AROUND A BIT THIS MORNING...WITH RUC SOUNDINGS CARRYING IT
INTO MID/LATE MORNING. HAVE LOWERED MAX TEMPS A BIT TODAY DUE TO
MORNING CLOUDS.
NUMBER OF MODELS CONTINUE TO CARRY LIGHT QPF FAR EASTERN WI TODAY.
NOT SEEING MUCH SUPPORT BESIDES SOME WEAK SURFACE CONVERGENCE...
THOUGH WITH CONTINUED MOIST AIR MASS AND ASSOCIATED INSTABILITY
CANNOT TOTALLY RULE OUT. WILL STAY DRY AT THIS TIME AND ADVISE
NEXT SHIFT.
FRONT BEGINS TO LIFT NORTH TONIGHT WITH BEST DYNAMICS OVER ND/MN.
EXPECT MCS A GOOD POSSIBILITY ON NOSE OF LLVL JET AS SUGGESTED BY MODELS.
GIVEN THERMAL PATTERN AND CORFIDI VECTORS...COMPLEX TO MOVE EAST
AND SOUTHEAST. MODELS SUGGEST COMPLEX MOVING INTO NORTHERN CWA BY
AFTERNOON. HAVE EXPANDED POPS GIVEN SCENARIO.
TEMPERATURES TO CONTINUE TO RUN WARMER THAN NORMAL THIS
PERIOD...THOUGH COOLER THAN PREVIOUS FEW DAYS.
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY
ISSUED AT 405 AM CDT WED AUG 28 2013
ALTHOUGH THERE ARE SOME TIMING DIFFERENCES AMONG THE
MODELS...PRECIPITATION CHANCES SHOULD BE HIGHEST ON THURSDAY
NIGHT AS AN UPPER LEVEL SHORT WAVE TOPS THE RIDGE. THERE WILL ALSO
BE ASSISTANCE FROM SOME 300MB DIVERGENCE AND AN APPROACHING
SURFACE SYSTEM.
THUNDERSTORM CHANCES REMAIN FOR FRIDAY AND SATURDAY WITH WARM AND
HUMID AIR IN PLACE...BUT DO NOT REALLY SEE MUCH FORCING. A COLD
FRONT PUSHING THROUGH TO START NEXT WEEK WILL BRING A CHANCE OF
SHOWERS AND THUNDERSTORMS THROUGH SUNDAY...AND COOLER
TEMPERATURES FOR MONDAY AND TUESDAY.
HAVE GENERALLY USED A MIX OF GUIDANCE AND PREVIOUS FORECAST
TEMPERATURES FOR MAX AND MIN TEMPERATURES DURING THE PERIOD.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1205 PM CDT WED AUG 28 2013
MVFR CIGS CONTINUED ACROSS CENTRAL AND PORTIONS OF NORTHEAST
WISCONSIN EARLY THIS AFTERNOON. AN UNUSUAL FOG EVENT OCCURRED
AT THE KGRB TAF SITE THIS MORNING AS FOG ROLLED OFF THE BAY ON
NORTHEAST WINDS BETWEEN 9 AM AND 11 AM. MOST SITES WILL CLIMB INTO
THE VFR CATEGORY LATE THIS AFTERNOON. THE ONLY EXCEPTION WILL BE
NEAR LAKE MICHIGAN WHERE SOME MVFR/IFR CONDITIONS COULD CONTINUE
DUE TO FOG OFF THE LAKE.
MAIN CONCERN FOR TONIGHT WILL BE THE FOG AND STRATUS POTENTIAL.
THE COMBINATION OF LIGHT WINDS...PARTLY CLOUDY SKIES AND RELATIVELY
HIGH DEW POINTS WOULD SUGGEST THAT FOG...MORE THAN LIKELY DENSE IN
SPOTS CAN BE EXPECTED. INTRODUCED SOME LIGHT FOG AROUND 03Z IN THE
TAFS AND THEN HIT THE TAFS HARD BETWEEN 06Z-15Z. AGAIN...SOME SITES
MAY DROP BELOW AIRPORT MINIMUMS. ANY LOWS AND FOG SHOULD BURN OFF
BY 15-16Z. IT APPEARS THERE IS A SMALL CHANCE OF SHOWERS AND STORMS
ACROSS THE WEST AND FAR NORTHWEST AFTER 18Z ON THURSDAY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....TE
LONG TERM......MG
AVIATION.......ECKBERG