Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/19/13
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1011 PM MDT MON SEP 16 2013
.UPDATE...
ISSUED AT 901 PM MDT MON SEP 16 2013
A FEW SHOWERS AND THUNDERSTORMS CONTINUE TO PERSIST OVER THE UINTA
MTNS IN NORTHEAST UTAH THIS EVENING...AND ADJUSTED THE GRIDDED
FORECAST ACCORDINGLY. A FAIR AMOUNT OF LIGHTNING INDICATED WITH
SOME OF THESE THUNDERSTORMS. ELSEWHERE ACROSS THE FORECAST
AREA...SHOWERS HAVE DIED DOWN WITH THE LOSS OF SOLAR HEATING.
PRECIPITABLE WATER OF 0.64 INCH ON THIS EVENING/S GJT SOUNDING WAS
DOWN CONSIDERABLY FROM THE 0.94 INCH MEASURED THIS MORNING. A
QUICK LOOK AT THE 00Z NAM AND 00Z RAP MODELS SHOW A WEAK
DISTURBANCE CROSSING THE SOUTH LATER TONIGHT...AND THE CURRENT
FORECAST MAINTAINS MENTION OF AN ISOLATED SHOWER OR STORM POSSIBLE
OVER THE SAN JUAN MTNS AFTER MIDNIGHT.
&&
.SHORT TERM...(TONIGHT THROUGH TUESDAY NIGHT)
ISSUED AT 356 PM MDT MON SEP 16 2013
LOCAL PROFILERS AND WATER VAPOR IMAGERY SHOWING THE TROF THAT HAS
BEEN LINGERING IN THE WEST FINALLY PUSHING ONTO THE PLAINS THIS
AFTERNOON. WEAKER UPSTREAM WAVE IS MOVING IN BEHIND A TRANSITORY
RIDGE IN NORTHERN UTAH AND PROVIDING A BIT MORE FOCUS FOR STORMS IN
OUR WESTERN CWA...WITH HEATING DRIVING ISOLATED CONVECTION
ELSEWHERE. A DIP IN THE WESTERLIES IS MOVING ONTO THE WEST COAST
THIS AFTERNOON WHICH WILL BE DRIVING A SERIES OF STRONGER OPEN OUT
OF THE EASTERN PACIFIC BEGINNING TONIGHT.
SOUNDINGS SHOW SOME DRIER AIR MOVING INTO THE LOWER LAYERS OF THE
PROFILE BUT MOISTURE STILL HANGING AROUND 600-500MB KEEPING PWATS
ABOVE NORMAL. GOES DERIVED TPW VERIFIES THE MOISTURE HANGING AROUND
THE VEGAS/WESTERN GREAT BASIN AREA AND UPSTREAM OFF THE CALIFORNIA
COAST ASSOCIATED WITH THE WESTERN TROF. THETA SURFACES NEAR 315-320K
SHOW THE FLOW TURNING SOUTHWESTERLY AND INCREASING LATE TONIGHT INTO
TUESDAY AND DRAWING MOISTURE BACK INTO OUR CWA. PIECES OF THE UPPER
JET COMBINE WITH INCREASING LARGE SCALE ASCENT BY THE AFTERNOON
WHICH SHOULD BRING AN UPTICK TO THE CONVECTION. THE STORMS LOOK TO
LINGER THROUGH THE OVERNIGHT HOURS AS THE JET SLOWLY SAGS SOUTHWARD
AND ASCENT INCREASES. TEMPERATURES SHOULD BE MAKING A REBOUND TO
ABOVE NORMAL BY TOMORROW BEFORE A WEAK FRONT PASSES THROUGH THE MID
WEEK.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 356 PM MDT MON SEP 16 2013
A CHANGE IN PATTERN FROM THE STAGNANT MONSOON FLOW TO PROGRESSIVE
WESTERLIES OCCURS THIS WEEK...UNOFFICIALLY ENDING THE MONSOON
SEASON.
WEDNESDAY A PACIFIC TROUGH WORKS THROUGH THE NORTHERN ROCKIES. A
WARM SW GRADIENT WIND WILL MIX DOWN IN THE AFTERNOON FOR BREEZY
WARM CONDITIONS. RESIDUAL MOISTURE IS SUFFICIENT FOR SCATTERED
MAINLY MOUNTAIN SHOWERS AND STORMS. THE ASSOCIATED COOL AND
DRY FRONT PUSHES INTO NE UTAH IN THE AFTERNOON PUSHES THROUGH THE
NORTHERN AND CENTRAL ZONES BECOMING STRETCHED WEST TO EAST
SOMEWHERE NEAR THE HIGHWAY 50 LINE BY THURSDAY MORNING. THIS WILL
USHER IN A DRIER AND COOLER AIR MASS FOR THURSDAY. TEMPERATURES
ACROSS PORTIONS OF NW COLORADO WILL FLIRT WITH THE FREEZING.
TEMPERATURES WILL RECOVER ON FRIDAY INTO SATURDAY TO NEAR NORMAL.
THEN NEXT PACIFIC TROUGH IS CURRENTLY TIMED TO PASS LATE SUNDAY...
WITH ANOTHER TROUGH LATER NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1010 PM MDT MON SEP 16 2013
VFR IS EXPECTED TO BE THE PREVAILING CONDITION AT THE TAF SITES FOR
THE REMAINDER OF TONIGHT THROUGH TUESDAY. AN ISOLATED -SHRA OR -TSRA
IS POSSIBLE OVER THE SAN JUAN MTNS THROUGH 18Z TUE. ISOLATED TO
SCATTERED -TSRA ARE EXPECTED BETWEEN 18Z TUE AND 03Z WED WITH THE
GREATER COVERAGE OVER THE HIGHER TERRAIN. MVFR CIGS AND GUSTY
OUTFLOW WINDS NEAR THE -TSRA WITH SOME MOUNTAIN TOP OBSCURATIONS.
ALSO...SOUTH TO SOUTHWEST SURFACE GRADIENT WINDS INCREASE TUE
AFTERNOON.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
UPDATE...JAD
SHORT TERM...15
LONG TERM...JOE
AVIATION...JAD
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1002 PM EDT WED SEP 18 2013
.SYNOPSIS...
HIGH PRESSURE WILL GRADUALLY SLIDE EAST OF THE REGION THROUGH THE
END OF THE WEEK PROVIDING MAINLY DRY WEATHER AND WARMING
TEMPERATURES THROUGH SATURDAY. A COLD FRONT WILL ENTER THE REGION
SAT NIGHT AND SUNDAY WITH SCATTERED RAIN SHOWERS POSSIBLE. THEN
LOTS OF UNCERTAINTY FOR NEXT WEEK AS LOW PRESSURE WITH TROPICAL
ORIGINS MAY DEVELOP OVER THE GULF OF MEXICO AND THEN TRACK
NORTHEAST INTO THE MID ATLANTIC REGION.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
10 PM UPDATE...
SKC CONDITIONS AND LIGHT TO CALM SW FLOW HAS ALLOWED RADIATIONAL
PROCESSES TO BE MORE EFFICIENT THAN GUIDANCE FORECAST. TEMPS ARE
ALREADY IN THE LOW 50S AND UPPER 40S IN AREAS WHERE THE GUIDANCE
SUGGESTS TEMPS SHOULD BE IN THE UPPER 50S. LATEST MAV AND LAV
GUIDANCE BASED ON RUC ARE CLOSEST BUT THESE TOO REQUIRED SOME
TWEAKS. OTHER FORECAST PARAMETERS ARE ARE ON TRACK SO NO CHANGES
NECESSARY OUTSIDE OF TEMPS/DWPTS.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
HIGH PRESSURE REMAINS IN CONTROL THROUGH THURSDAY NIGHT AS THE
HIGH PRESSURE CENTER SLIDES EAST SLOWLY JUST SOUTH OF SOUTHERN NEW
ENGLAND. TEMPERATURES CONTINUE TO MODERATE AS THE MID LEVEL RIDGE
CRESTS OVER THE AREA DURING THE DAY. TEMPERATURES ARE EXPECTED TO
BE IN THE UPPER 70S WITH A FEW LOCATIONS POSSIBLY HITTING 80 IN
WESTERLY DOWNSLOPING LIGHT WINDS. OVERNIGHT...LOWS WILL BE STILL A
FEW DEGREES WARMER...GENERALLY IN THE 50S.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
HIGHLIGHTS...
* DRY AND MILD WEATHER FRI INTO SAT AFTERNOON
* COLD FRONT BRINGS A PERIOD OF RAIN SHOWERS SAT NIGHT/SUN
* COOLER EARLY NEXT WEEK WITH POSSIBLE RAIN
GOOD MODEL AGREEMENT ON RIDGING ACROSS THE NORTHEAST FRI AND SAT
PROVIDING DRY AND WARM WEATHER TO SOUTHERN NEW ENGLAND. NORTHERN
STREAM TROUGH AND ATTENDING COLD FRONT EXITS THE GREAT LAKES SAT.
GOOD MODEL AGREEMENT ON NORTHERN STREAM TROUGH DEAMPLIFYING AS IT
TRAVERSE NORTHEAST INTO ONTARIO/QUEBEC. THE QUESTION THEN BECOMES
HOW MUCH JET ENERGY IS LEFT BEHIND OVER THE SOUTHERN STATES AS THE
NORTHERN STREAM TROUGH SHEARS/PEELS OFF TO THE NORTHEAST. MODELS
HANDLING THE SPLITTING OF THIS JET ENERGY VERY DIFFERENTLY...THUS
VERY LOW CONFIDENCE FROM SUN INTO EARLY NEXT WEEK.
THE 18/12Z GUIDANCE INCLUDING THE GEFS CONTINUES TO SUGGEST A
TROPICAL LOW IN THE SOUTHWEST GULF OF MEXICO WILL EJECT
NORTHEASTWARD AND INTERACT WITH A DECAYING/FRACTURED FRONTAL
BOUNDARY ALONG THE EAST COAST SUN INTO EARLY NEXT WEEK. 12Z GFS
SUGGEST A CLOSE CALL WITH CYCLONE EXITING OFF THE MID ATLC COAST.
12Z ECMWF HAS BACKED OFF ITS ROBUST 00Z SOLUTION. THE 12Z ENSEMBLES
/BOTH GEFS AND ECENS/ INDICATE LOTS OF SPREAD IN THE H5 FIELD. HENCE
LOW CONFIDENCE FORECAST. WILL STICK WITH CHANCE POPS SUN THROUGH WED
TO COMMUNICATE THE POTENTIAL FOR SHOWERS AND THE UNCERTAINTY.
AS FOR POPS AND TEMPS WERE DERIVED FROM AN EVEN BLEND OF HPC AND
GMOS.
DETAILS...
FRI...
NICE WEATHER CONTINUES WITH HIGH PRES NEARBY PROVIDING LIGHT WINDS
ALONG WITH WARM TEMPS AND DRY CONDITIONS.
SAT...
HIGH PRES MOVES FARTHER OFFSHORE WITH INCREASING SSW WINDS YIELDING
HIGHER DEW PTS /ALBEIT MODEST WITH VALUES IN THE 60S/ INTO SOUTHERN
NEW ENGLAND. NEVERTHELESS NICE SEP WEATHER CONTINUES WITH HIGHS IN
THE MU70S. LOW RISK OF A SHOWERS LATE IN THE DAY EXTREME WESTERN NEW
ENGLAND.
SATURDAY NIGHT THROUGH SUNDAY NIGHT...
A COLD FRONT WILL SLOWLY MOVE ACROSS THE REGION YIELDING SCATTERED
SHOWERS. NOT EXPECTING A WASHOUT AT THIS POINT. INSTABILITY LOOKS
RATHER LIMITED...SO HAVE DECIDED NOT KEEP THUNDER OUT OF THE
FORECAST
MONDAY THROUGH WEDNESDAY...
AS MENTIONED ABOVE LOTS OF UNCERTAINTY REGARDING THIS PORTION OF THE
FORECAST. WILL KEEP CHANCE POPS IN THE FORECAST TO ADDRESS THIS
UNCERTAINTY.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH THURSDAY NIGHT/...HIGH CONFIDENCE.
7 PM UPDATE...
NO CHANGES FROM PREVIOUS FORECAST.
VFR THROUGH THE PERIOD EXCEPT FOR A FEW SPOTS OF PATCHY GROUND FOG
IN THE TYPICALLY PRONE LOCATIONS LATE TONIGHT AND AGAIN THURSDAY
NIGHT. WINDS ARE CURRENTLY STRONG ENOUGH /3-5 KTS/ THAT A SEA
BREEZE HAS NOT YET FORMED. HOWEVER...THEY ARE ON THE LIGHT SIDE SO
THE WINDS COULD SHIFT TO THE EAST OR SOUTHEAST AT ANY POINT THIS
AFTERNOON.
KBOS TERMINAL...HIGH CONFIDENCE IN VFR CONDITIONS AND TAF.
SOUTHEAST SEA BREEZE LIKELY.
KBDL TERMINAL...HIGH CONFIDENCE IN VFR CONDITIONS AND TAF.
OUTLOOK...FRIDAY THROUGH MONDAY...
FRI AND SAT...HIGH CONFIDENCE FOR VFR/LIGHT WINDS AND DRY WEATHER.
SAT NIGHT/SUN/MON...MODERATE CONFIDENCE. A PERIOD OR TWO OF MVFR-
IFR CONDITIONS ARE POSSIBLE IN SOME RAIN SHOWERS.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH THURSDAY NIGHT/...HIGH CONFIDENCE.
HIGH PRESSURE BUILDS OVER THE WATERS THROUGH THURSDAY NIGHT.
THEREFORE...QUIET BOATING WEATHER IS EXPECTED.
OUTLOOK...FRIDAY THROUGH MONDAY...
FRI...NICE BOATING WEATHER CONTINUES WITH LIGHT WINDS/GOOD VSBY AS
HIGH PRES REMAINS NEARBY.
SAT...HIGH MOVES OFFSHORE WITH INCREASING SSW WINDS. POSSIBLE
SHOWERS SAT NIGHT FROM WEST TO EAST.
SUN/MON...LOTS OF UNCERTAINTY REGARDING LOW PRES EXITING THE GULF OF
MEXICO TO THE MID ATLC STATES.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...NOCERA/RLG
NEAR TERM...DOODY
SHORT TERM...RLG
LONG TERM...NOCERA
AVIATION...NOCERA/RLG
MARINE...NOCERA/RLG
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
230 PM EDT TUE SEP 17 2013
.SYNOPSIS...
18Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS AN UPPER LEVEL PATTERN
THAT IS HIGHLY AMPLIFIED TO THE NORTH THROUGH THE MIDDLE SECTION OF
THE COUNTRY. THIS LARGE RIDGE SITS BETWEEN TWO SHARP TROUGHS ALONG
BOTH THE PACIFIC AND ATLANTIC SEABOARDS. THE FLORIDA PENINSULA
RESIDES UNDER A WEAK UPPER LEVEL PATTERN ON THE EASTERN PERIPHERY OF
ELONGATED UPPER RIDGING ALONG THE NORTHERN GULF COAST.
AT THE SURFACE...FORECAST AREA RESIDES WITHIN A FAIRLY TIGHT
PRESSURE GRADIENT ZONE BETWEEN STRONG 1025+MB HIGH PRESSURE RIDGING
DOWN THE ATLANTIC SEABOARD...AND A WEAK AREA OF LOW PRESSURE NEAR
THE YUCATAN PENINSULA OF MEXICO. THIS GRADIENT IS PROVIDING A
DEFINED EASTERLY TO NORTHEASTERLY LOW LEVEL FLOW ACROSS THE
PENINSULA. SCT TO NMRS GENERALLY SHALLOW SHOWERS AND A FEW STORMS
ARE NOW FORMING INLAND FROM THE FL EAST COAST AND RAPIDLY
PROPAGATING WESTWARD WITHIN THIS FLOW. THE GREATEST COVERAGE OF
STORMS THROUGH THE REMAINDER OF THE AFTERNOON LOOKS TO BE SOUTH OF
THE I-4 CORRIDOR...WITH MORE WIDELY SCT ACTIVITY FURTHER TO THE
NORTH ACROSS THE NATURE COAST. THIS SCENARIO IS IN GOOD AGREEMENT
WITH THE LATEST HI-RESOLUTION GUIDANCE ENSEMBLE.
&&
.SHORT TERM (TONIGHT THROUGH THURSDAY)...
TONIGHT...
SHOWERS AND STORMS PUSH OFFSHORE DURING THE EVENING HOURS...AND THE
PATTERN SUGGEST WE WILL LIKELY SEE AT LEAST SOME CONVECTIVE COVERAGE
OVER THE SOUTHERN COASTAL WATERS WELL INTO THE OVERNIGHT. HIGH
PRESSURE BUILDING DOWN THE EASTERN SEABOARD FROM THE MID-ATLANTIC
STATES WILL ALSO SET UP A GOOD SYNOPTIC PATTERN TO SUPPORT A
NOCTURNAL EASTERLY WIND SURGE OVER THE COASTAL WATERS. THIS SURGE
THAT IS FORECAST TO REACH CAUTIONARY LEVELS...SHOULD BEGIN SHORTLY
AFTER SUNSET...AND BE MOST NOTABLE THE FURTHER NORTH FROM ENGLEWOOD
ONE TRAVELS.
WEDNESDAY/WEDNESDAY NIGHT...
THE SYNOPTIC SETUP FOR WEDNESDAY APPEARS VERY SIMILAR TO WHAT WE ARE
EXPERIENCING TODAY (TUESDAY). UPPER LEVELS SHOW WEAK FLOW ON THE
EASTERN SIDE OF A BROAD...BUT NOT STRONG....UPPER RIDGE. AT THE
SURFACE...RIDGING CONTINUES TO BUILD DOWN THE EASTERN SEABOARD...AND
IF ANYTHING...THE GRADIENT IS TIGHTER AND THE RESULTING LOW LEVEL
FLOW A TAD STRONGER. ONCE AGAIN THE COLUMN WILL BE QUITE MOIST...AND
THIS COMBINED WITH THE FAVORABLE EASTERLY FLOW SHOULD SUPPORT
SCT-NMRS SHOWERS AND STORMS...WITH THE GREATEST COVERAGE ALONG AND
SOUTH OF I-4. CURRENT FORECAST RAIN CHANCES SHOW 60-65% ALONG AND
SOUTH OF I-4 AND 40-55% FURTHER NORTH. ASIDE FROM THE ACTUAL RAIN
CHANCES...THE MID-LEVELS DO NOT LOOK TO SUPPORT MANY STRONGER
UPDRAFTS. 500MB TEMPS ARE FAIRLY WARM AT -6C AND THIS SHOULD HELP
SUPPRESS MUCH IN THE WAY OF STRONG/SEVERE STORMS...AND EVEN
EFFICIENT CHARGE SEPARATION FOR MANY FREQUENT LIGHTNING PRODUCERS.
OF COURSE...ALL LIGHTNING IS DANGEROUS...REGARDLESS OF ITS
FREQUENCY. THE SPATIAL AND TEMPORAL EVOLUTION OF THE STORMS SHOULD
FOLLOW A SIMILAR PATTERN TO TUESDAY AS WELL. DAY WILL START WITH
SPEED CONVERGENCE SHOWERS ALONG THE FLORIDA EAST COAST. THESE WILL
STRUGGLE TO MOVE INLAND THROUGH LATE MORNING AND THEN CONVECTION
WILL BEGIN INLAND ALONG RESIDUAL OUTFLOW BOUNDARIES AND PROPAGATE
RAPIDLY WESTWARD ACROSS OUR ZONES. TEMPERATURES APPEAR SEASONABLE BY
MID-AFTERNOON REACHING THE LOW 90S FOR MOST SPOTS THAT DO NOT SEE AN
EARLY SHOWER.
ANY LEFTOVER EVENING STORMS PUSH OFFSHORE BY 02-03Z LEAVING A
GENERALLY DRY OVERNIGHT INTO EARLY THURSDAY MORNING. THE RIDGE
POSITION TO OUR NORTH WILL SUPPORT ANOTHER CAUTIONARY EASTERLY WIND
SURGE FOR THE COASTAL WATERS...ESPECIALLY FROM OFFSHORE OF TAMPA BAY
NORTHWARD ALONG THE NATURE COAST.
THURSDAY...
PATTERN STILL DOES NOT CHANGE A WHOLE LOT INTO THURSDAY. A SLIGHTLY
MORE AMPLIFIED MID/UPPER LEVEL RIDGE TO OUR WEST IS SHOWN BY THE GFS
TO BEGIN DELIVERING SOME DRIER MID-LEVEL AIR TO THE NATURE COAST
ZONES BEFORE THE DAY IS THROUGH. DEPENDING ON THE EXACT TIMING OF
THIS DRIER AIR...RAIN CHANCES FOR THE NATURE COAST MAY NEED TO BE
ADJUSTED DOWNWARD SLIGHTLY. EITHER WAY...BEST RAIN CHANCES THURSDAY
AFTERNOON/EARLY EVENING WILL ONCE AGAIN BE ALONG AND SOUTH OF I-4.
CURRENTLY FORECASTING 55-65% SOUTH OF I-4 AND 30-45% FURTHER NORTH.
&&
.LONG TERM (FRIDAY THROUGH NEXT MONDAY)...
MEDIUM RANGE GUIDANCE IS IN GOOD AGREEMENT THROUGH THE REMAINDER OF
THE WORK WEEK...WITH SOLUTIONS THEN DIVERGING OVER THE UPCOMING
WEEKEND AND INTO EARLY NEXT WEEK. THE 00Z CANADIAN MODEL COMPARED
WITH THE GFS/ECMWF IS DEVELOPING A TROPICAL CYCLONE IN THE GULF OF
MEXICO BY SATURDAY EVENING. ALTHOUGH NOT IMPOSSIBLE GIVEN THE
GENERALLY FAVORABLE CONDITIONS OVER THE GULF...ONE OF THE BIASES OF
THE CANADIAN MODEL IS TO OVERDEVELOP TROPICAL CYCLONES DUE TO
INTERACTION WITH LARGE SCALE SYNOPTIC FEATURES. AS A RESULT...WILL
FOLLOW A BLEND OF THE 00Z GFS AND 00Z ECMWF FOR FORECAST DETAILS
THROUGH THE LONG TERM PERIODS.
HIGH PRESSURE WILL REMAIN NORTH OF THE FORECAST AREA FOR THE TAIL
END OF THE WORK WEEK AND INTO THE UPCOMING WEEKEND...RESULTING IN
PREVAILING EASTERLY FLOW WITH ISOLATED TO WIDELY SCATTERED SEA
BREEZE DRIVEN CONVECTION EACH AFTERNOON/EVENING THROUGH SATURDAY.
HIGH PRESSURE NORTH OF THE STATE WILL WEAKEN AS A FRONTAL BOUNDARY
PUSHES SOUTHWARD TOWARD THE NORTHERN GULF COAST AND STALLS OUT BY
SUNDAY. THIS WILL RESULT IN AN INCREASE IN DEEP LAYER MOISTURE
ACROSS THE ENTIRE FORECAST AREA...SUNDAY THROUGH NEXT TUESDAY. THE
GFS AND ECMWF MODELS TO DIFFERING DEGREES CONTINUE TO SHOW A BROAD
AREA OF LOW PRESSURE WITH PLENTY OF DEEP LAYER MOISTURE IN PLACE
OVER THE GULF OF MEXICO. THE CANADIAN ON THE OTHER HAND AS
MENTIONED ABOVE...HAS A FAIRLY IMPRESSIVE TROPICAL CYCLONE MAKING
LANDFALL ALONG THE NORTHERN GULF COAST ON SUNDAY. GIVEN THE TIME
OF YEAR AND SOME INDICATIONS OF POTENTIAL DEVELOPMENT IN THE
NUMERICAL MODEL GUIDANCE...WILL NEED TO CLOSELY MONITOR TRENDS AS
THE WEEK PROGRESSES FOR THE POTENTIAL FOR TROPICAL CYCLONE
DEVELOPMENT.
TEMPERATURES ARE EXPECTED TO RUN CLOSE TO CLIMO THROUGH THE LONG
TERM PERIODS.
&&
.AVIATION...
VFR CONDITIONS ARE GIVING WAY TO SOME TEMPO MVFR/LCL IFR...
ESPECIALLY AT PGD/FMY/RSW. ALL TERMINALS ARE EXPECTED TO SEE VCNTY
TSRA THROUGH 00/01Z...THEN VFR RETURNS. EASTERLY FLOW PREVAILS
ALTHOUGH WINDS OVERNIGHT WILL BACK AND SLACKEN SOME.
&&
.MARINE...
EASTERLY WINDS WILL CONTINUE FOR THE NEXT SEVERAL DAYS. HIGH
PRESSURE BUILDING DOWN THE EASTERN SEABOARD FROM THE MID-ATLANTIC
STATES WILL ALSO SET UP A GOOD SYNOPTIC PATTERN TO SUPPORT A
NOCTURNAL EASTERLY WIND SURGE OVER THE COASTAL WATERS. THIS SURGE IS
FORECAST TO REACH CAUTIONARY LEVELS...SHOULD BEGIN SHORTLY AFTER
SUNSET...AND BE MOST NOTABLE THE FURTHER NORTH FROM ENGLEWOOD ONE
TRAVELS. ANOTHER EASTERLY SURGE TO CAUTIONARY LEVELS CAN BE EXPECTED
WEDNESDAY NIGHT.
&&
.FIRE WEATHER...
HIGH PRESSURE TO OUR NORTH THE NEXT SEVERAL DAYS WILL KEEP A MOIST
EASTERLY FLOW OFF THE ATLANTIC A FEATURE OF THE FORECAST. RELATIVE
HUMIDITY IS EXPECTED TO REMAIN WELL ABOVE CRITICAL LEVELS THROUGH
THE NEXT SEVERAL DAYS. ONLY FIRE WEATHER CONCERN BESIDES THE
CONTINUED THREAT FOR SCATTERED AFTERNOON STORMS WILL BE HIGH
DISPERSION INDICES THAT WILL APPROACH FOR SURPASS 75 TO THE NORTH
OF I-4 THE BOTH WEDNESDAY AND THURSDAY AFTERNOONS. SOME PATCHY
GROUND FOR IS POSSIBLE LATE THE NEXT FEW NIGHTS FOR LOCATIONS THAT
RECEIVE LATE DAY RAINS...BUT NO SIGNIFICANT FOG DEVELOPMENT IS
ANTICIPATED.
&&
.HYDROLOGY...
RECENT RAINFALL HAS CAUSED ELEVATED WATER LEVELS ON MANY RIVERS AND
ACROSS THE AREA. CURRENTLY...THE LITTLE MANATEE RIVER NEAR WIMAUMA
AND THE MANATEE RIVER AT MYAKKA HEAD ARE IN ACTION STAGE...AND
ALTHOUGH WATER LEVELS ON THESE RIVERS ARE EXPECTED TO DECREASE
TODAY...ADDITIONAL RAINFALL LATER THIS WEEK MAY BRING THESE RIVERS
BACK ABOVE FLOOD STAGE.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 75 90 75 90 / 20 60 20 50
FMY 73 91 74 91 / 20 60 20 60
GIF 72 91 72 91 / 10 60 20 50
SRQ 74 90 74 92 / 20 60 20 50
BKV 71 91 71 91 / 20 50 20 40
SPG 77 90 77 90 / 20 60 20 50
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
AVIATION...RUDE
LONG TERM...JELSEMA
HYDROLOGY...LEWIS
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1020 AM EDT TUE SEP 17 2013
.SHORT TERM (TODAY-THURSDAY)...
14Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS AN UPPER LEVEL PATTERN
THAT IS HIGHLY AMPLIFIED TO THE NORTH THROUGH THE MIDDLE SECTION OF
THE COUNTRY FOR THE MIDDLE OF SEPTEMBER. THIS LARGE RIDGE SITS
BETWEEN TWO SHARP TROUGHS ALONG BOTH THE PACIFIC AND ATLANTIC
SEABOARDS. THE FLORIDA PENINSULA RESIDES UNDER A WEAK UPPER LEVEL
PATTERN ON THE EASTERN PERIPHERY OF ELONGATED UPPER RIDGING ALONG
THE NORTHERN GULF COAST.
12Z KTBW SOUNDING PROFILE IS RATHER MOIST WITH A PW VALUE
APPROACHING 2". HOWEVER...LAPSE RATE...ESPECIALLY IN THE MID-LEVELS
/ HAIL GROWTH ZONE ARE NOT IMPRESSIVE. THE MOIST ATMOSPHERE AND
EASTERLY LOW LEVEL FLOW REGIME SUGGEST WE WILL STILL HAVE AN ACTIVE
CONVECTIVE AFTERNOON/EARLY EVENING...ESPECIALLY FROM I-4
SOUTHWARD...BUT MUCH ROBUST CONVECTION WITH SEVERE SUPPORTIVE
UPDRAFTS APPEARS UNLIKELY. ISOLATED CONVECTIVE CELL CAN ALWAYS
SURPRISE YOU IF IT FINDS A LOCAL REGION OF GOOD LOW LEVEL
FOCUS...BUT OVERALL A MORE MODERATED DAY OF CONVECTIVE STRENGTH
SEEMS LIKELY.
HAVE SEEN SOME SHOWERS/STORMS ALONG THE FLORIDA EAST COAST WITHIN
THE ZONE OF EASTERLY SPEED CONVERGENCE. AS WOULD BE EXPECTED...THIS
ACTIVITY DISSIPATES QUICKLY AS IT TRIES TO MOVE INLAND AND AWAY FROM
THIS NARROW FOCUS ZONE. WITH THIS IN MIND...SHOULD HAVE A FEW MORE
HOURS OF GENERALLY DRY CONDITIONS ACROSS OUR FORECAST AREA BEFORE
DIURNAL HEATING AND RESIDUAL OUTFLOW BOUNDARIES START THE EARLY
AFTERNOON CONVECTIVE PROCESS.
BASED ON LATEST HI-RES CONVECTIVE ALLOWING GUIDANCE SUITE...CURRENT
LATE DAY RAIN CHANCES OF 25-40% NORTH OF I-4 AND 50-60% FURTHER
SOUTH STILL APPEAR ON TRACK. THE DEEPEST MOISTURE IS CERTAINLY OVER
THE SOUTHERN 2/3RDS OF THE FORECAST AREA THIS AFTERNOON AND IS
LIKELY WHAT THE GUIDANCE IS PICKING UP ON TO SUPPORT THE GREATER
CONVECTIVE COVERAGE FROM TAMPA BAY SOUTHWARD.
TONIGHT...
SHOWERS AND STORMS PUSH OFFSHORE DURING THE EVENING HOURS...AND THE
PATTERN SUGGEST WE WILL LIKELY SEE AT LEAST SOME CONVECTIVE COVERAGE
OVER THE SOUTHERN COASTAL WATERS WELL INTO THE OVERNIGHT. HIGH
PRESSURE BUILDING DOWN THE EASTERN SEABOARD FROM THE MID-ATLANTIC
STATES WILL ALSO SET UP A GOOD SYNOPTIC PATTERN TO SUPPORT A
NOCTURNAL EASTERLY WIND SURGE OVER THE COASTAL WATERS. THIS SURGE IS
FORECAST TO REACH CAUTIONARY LEVELS...SHOULD BEGIN SHORTLY AFTER
SUNSET...AND BE MOST NOTABLE THE FURTHER NORTH FROM ENGLEWOOD ONE
TRAVELS.
&&
.AVIATION...
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT ALL TERMINALS THIS MORNING
INTO THE EARLY AFTERNOON HOURS. SCATTERED SHRA/TSRA SHOULD DEVELOP
EARLY AFTERNOON...SO WILL CURRENTLY KEEP VCTS AT 18Z FOR SOUTHERN
AIRPORTS AND 19Z FROM SRQ NORTHWARD. WILL HAVE TO MONITOR THIS AND
ADJUST WITH TEMPO GROUPS FOR POSSIBLE CIG/VIS CONDITIONS IN TSRA AS
SHOWERS/STORMS MOVE WESTWARD. VFR CONDITIONS ARE EXPECTED OVERNIGHT.
&&
.MARINE...
EASTERLY WINDS WILL CONTINUE FOR THE NEXT SEVERAL DAYS. HIGH
PRESSURE BUILDING DOWN THE EASTERN SEABOARD FROM THE MID-ATLANTIC
STATES WILL ALSO SET UP A GOOD SYNOPTIC PATTERN TO SUPPORT A
NOCTURNAL EASTERLY WIND SURGE OVER THE COASTAL WATERS. THIS SURGE IS
FORECAST TO REACH CAUTIONARY LEVELS...SHOULD BEGIN SHORTLY AFTER
SUNSET...AND BE MOST NOTABLE THE FURTHER NORTH FROM ENGLEWOOD ONE
TRAVELS. ANOTHER EASTERLY SURGE TO CAUTIONARY LEVELS CAN BE EXPECTED
WEDNESDAY NIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 90 75 90 75 / 50 20 50 20
FMY 89 73 90 74 / 60 20 60 20
GIF 91 72 91 72 / 50 20 50 20
SRQ 91 74 90 74 / 50 20 60 20
BKV 91 70 91 70 / 40 20 50 20
SPG 90 77 89 77 / 50 20 60 20
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE/MARINE...MROCZKA
AVIATION...RUDE/WYNN
AREA FORECAST DISCUSSION
NWS POCATELLO ID
750 AM MDT TUE SEP 17 2013
.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT. A QUICK UPDATE THIS
MORNING TO ADD SEVERE WORDING TO GOING FORECAST THIS AFTERNOON AS
INCOMING FRONT AND UPPER DYNAMICS COMBINE TO PRODUCE VERY STRONG
THUNDERSTORMS. SEE PREVIOUS DISCUSSION BELOW. HUSTON
A VERY ACTIVE 48 HOUR PERIOD IS AHEAD FOR EASTERN IDAHO. WE ALREADY
HAD A ROUND OF STRONG/SEVERE STORMS THIS MORNING AND ANOTHER ROUND
IS ON TAP FOR LATER TODAY. THE MAIN FEATURE WITH STORM OFFSHORE WILL
SWING INTO WASHINGTON AND OREGON. THIS...ALONG WITH A COLD FRONT
ENTERING INTO WESTERN PORTIONS OF THE FORECAST AREA WILL KEEP
SHOWERS AND THUNDERSTORMS AROUND WITH COVERAGE RAMPING UP THIS
AFTERNOON. MOST AREAS WILL SEE SCATTERED TO NUMEROUS SHOWERS AND
STORMS...WITH EXCEPTION FOR THE MAGIC VALLEY AND WEST OF OAKLEY
WHERE ISOLATED ACTIVITY IS FORECAST. THE FRONT SHOULD BE THROUGH
THEM BEFORE THINGS GET GOING. THE THREAT OF STRONG/SEVERE STORMS
WITH HAIL AND STRONG WINDS EXISTS TODAY ESPECIALLY ACROSS THE
MOUNTAINS AND ALONG/AHEAD OF THE COLD FRONT ACROSS THE SNAKE PLAIN.
BY TONIGHT AND WEDNESDAY...THE FOCUS FOR SHOWERS WILL SHIFT TO THE
CENTRAL MOUNTAINS AND UPPER SNAKE HIGHLANDS. I KNOW SOME AREN`T
GOING TO BE READY OR LIKE THIS..BUT LIGHT SNOW IS FORECAST ABOVE
7500FT TONIGHT/EARLY WEDNESDAY ACROSS THE CENTRAL MOUNTAINS.
YOU CAN EXPECT BREEZY/WINDY CONDITIONS ACROSS THE AREA...WITH
SOUTHERLY WINDS AHEAD OF THE FRONT AND MORE WESTERLY IN ITS WAKE.
SUSTAINED WINDS OF 15-30MPH WITH HIGHER GUSTS ARE LIKELY...OUTSIDE
OF THUNDERSTORMS...THROUGH THIS EVENING. THE RIDGETOPS MAY SEE
SUSTAINED WINDS CLOSER TO 30-35MPH AT THEIR PEAK. WIND SPEEDS COME
DOWN SOME ESPECIALLY ACROSS THE CENTRAL MOUNTAINS AND UPPER SNAKE
HIGHLANDS TONIGHT AND TOMORROW. THEY`LL STILL BE BREEZY ACROSS
MOST OF THE SNAKE PLAIN AND SOUTHERN MOUNTAINS HOWEVER. WE HAVE A
LAKE WIND ADVISORY OUT FOR THIS AFTERNOON UNTIL JUST BEFORE
SUNSET. ANOTHER ONE IS LIKELY FOR TOMORROW AS WELL. CONDITIONS ARE
JUST NOT QUITE THERE FOR A WIND ADVISORY AT LOWER ELEVATIONS BUT
WE WILL BE MONITORING THIS AS WINDS WILL BE FLIRTING WITH THE
LOWER THRESHOLD OF 30MPH SUSTAINED TOMORROW. IT WILL CERTAINLY
FEEL LIKE FALL WITH COLDER TEMPERATURES ARRIVING BEHIND THE FRONT.
WE ARE LOOKING AT A 10-15 DEGREE DIFFERENCE BETWEEN TODAY AND
TOMORROW...WITH THE VALLEYS STRUGGLING TO GET ABOVE 65. WEDNESDAY
NIGHT WILL BE DOWNRIGHT COLD IN SOME AREAS. IT LOOKS LIKE MANY
AREAS WILL SEE 20S AND 30S FOR LOWS. THE EXCEPTIONS WILL BE ACROSS
THE SOUTHERN HIGHLANDS WHERE VALLEY TEMPERATURES WILL BOTTOM OUT
IN THE LOW 40S..AND PLACES LIKE STANLEY AND COPPER BASIN WHERE IT
WILL DROP INTO THE TEENS. KEYES
.LONG TERM...THURSDAY THROUGH NEXT TUESDAY. THE END OF THE WEEK
WILL SEE HIGH PRESSURE BUILDING AND SHIFTING EASTWARD OVER IDAHO.
THIS WILL ALLOW FOR A QUICK WARMUP WITH DRY CONDITIONS THROUGH
SATURDAY MORNING. FOR THE TRUE ARRIVAL OF FALL EARLY NEXT
WEEK...THE OVERALL PATTERN SETTLES BACK INTO GENERAL LOW PRESSURE
OVER THE WEST. THERE WILL BE MULTIPLE SYSTEMS IN THE PATTERN THAT
WILL KEEP THE CHANCE OF SHOWERS AROUND WITH A FEW THUNDERSTORMS.
KEYES
&&
.AVIATION...TRONG SHOWERS AND THUNDERSTORMS HAVE PASSED TO THE
DOWNWIND SIDE OF ALL AIRDROMES EXCEPT KIDA. -TSRA WILL CONTINUE AND
INCREASE IN COVERAGE AS INSTABILITY DEVELOPS AHEAD OF A COLD FRONT
EXPECTED LATE THIS AFTERNOON/EARLY THIS COMING EVENING...PASSING
THROUGH ALL AIRDROMES BY 18/03Z. -TSRA PROBABILITY BORDERS ON 50
PERCENT FOR KIDA AND KPIH...BUT TEMPO GROUPS NOT ALLOWED BEYOND 6
HOUR POINT. WILL TRY TO USE LATEST HRRR GUIDANCE TO FORECAST A
THUNDERSTORM TIME. FRONTAL PASSAGE IS FROM WEST TO EAST...WITH KIDA
BEING THE LAST. STRONG GRADIENT BEHIND THE FRONT MEANS AN UNUSUALLY
WINDY OVERNIGHT PERIOD TONIGHT. STRONG WIND CONTINUES WED AFTERNOON.
MESSICK
&&
.FIRE WEATHER...ERY UNSTABLE CONDITIONS TODAY WITH A FRONT ARRIVING
IN THE LATE AFTERNOON OVER EASTERN IDAHO. EXPECT A STORMY AND WINDY
DAY...CONTINUING INTO A STORMY AND WINDY NIGHT. FRONT WILL PASS OUT
OF EASTERN IDAHO BY MIDNIGHT TONIGHT...BUT STRONG WINDS WILL
CONTINUE OVERNIGHT AND INCREASE AGAIN TOMORROW AFTERNOON.
THUNDERSTORM ACTIVITY WILL BE LIMITED ON WED TO MAINLY THE TARGHEE
PORTION OF THE CARIBOU-TARGHEE NF. HIGH PRESSURE WILL MOVE IN FOR
THE LAST HALF OF THE WORK WEEK AND FOR AT LEAST A PORTION OF THE
WEEKEND. A STRONG LOW AND COLD FRONT ARE EXPECTED TO REACH IDAHO SAT
NIGHT OR SUN MORNING. NEITHER THE FRONT TODAY NOR THE WEEKEND FRONT
SHOULD BRING MUCH RAINFALL. MAIN ISSUE WILL BE STRONG WIND WITH A
90 KNOT UPPER LEVEL JET OVERHEAD TODAY MIXING DOWNWARD IN THE
UNSTABLE AIR. MESSICK
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM MDT THIS EVENING
IDZ021.
&&
$$
AREA FORECAST DISCUSSION
NWS POCATELLO ID
337 AM MDT TUE SEP 17 2013
.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT. A VERY ACTIVE 48 HOUR
PERIOD IS AHEAD FOR EASTERN IDAHO. WE ALREADY HAD A ROUND OF
STRONG/SEVERE STORMS THIS MORNING AND ANOTHER ROUND IS ON TAP FOR
LATER TODAY. THE MAIN FEATURE WITH STORM OFFSHORE WILL SWING INTO
WASHINGTON AND OREGON. THIS...ALONG WITH A COLD FRONT ENTERING
INTO WESTERN PORTIONS OF THE FORECAST AREA WILL KEEP SHOWERS AND
THUNDERSTORMS AROUND WITH COVERAGE RAMPING UP THIS AFTERNOON.
MOST AREAS WILL SEE SCATTERED TO NUMEROUS SHOWERS AND
STORMS...WITH EXCEPTION FOR THE MAGIC VALLEY AND WEST OF OAKLEY
WHERE ISOLATED ACTIVITY IS FORECAST. THE FRONT SHOULD BE THROUGH
THEM BEFORE THINGS GET GOING. THE THREAT OF STRONG/SEVERE STORMS
WITH HAIL AND STRONG WINDS EXISTS TODAY ESPECIALLY ACROSS THE
MOUNTAINS AND ALONG/AHEAD OF THE COLD FRONT ACROSS THE SNAKE
PLAIN. BY TONIGHT AND WEDNESDAY...THE FOCUS FOR SHOWERS WILL SHIFT
TO THE CENTRAL MOUNTAINS AND UPPER SNAKE HIGHLANDS. I KNOW SOME
AREN`T GOING TO BE READY OR LIKE THIS..BUT LIGHT SNOW IS FORECAST
ABOVE 7500FT TONIGHT/EARLY WEDNESDAY ACROSS THE CENTRAL MOUNTAINS.
YOU CAN EXPECT BREEZY/WINDY CONDITIONS ACROSS THE AREA...WITH
SOUTHERLY WINDS AHEAD OF THE FRONT AND MORE WESTERLY IN ITS WAKE.
SUSTAINED WINDS OF 15-30MPH WITH HIGHER GUSTS ARE LIKELY...OUTSIDE
OF THUNDERSTORMS...THROUGH THIS EVENING. THE RIDGETOPS MAY SEE
SUSTAINED WINDS CLOSER TO 30-35MPH AT THEIR PEAK. WIND SPEEDS COME
DOWN SOME ESPECIALLY ACROSS THE CENTRAL MOUNTAINS AND UPPER SNAKE
HIGHLANDS TONIGHT AND TOMORROW. THEY`LL STILL BE BREEZY ACROSS
MOST OF THE SNAKE PLAIN AND SOUTHERN MOUNTAINS HOWEVER. WE HAVE A
LAKE WIND ADVISORY OUT FOR THIS AFTERNOON UNTIL JUST BEFORE
SUNSET. ANOTHER ONE IS LIKELY FOR TOMORROW AS WELL. CONDITIONS ARE
JUST NOT QUITE THERE FOR A WIND ADVISORY AT LOWER ELEVATIONS BUT
WE WILL BE MONITORING THIS AS WINDS WILL BE FLIRTING WITH THE
LOWER THRESHOLD OF 30MPH SUSTAINED TOMORROW. IT WILL CERTAINLY
FEEL LIKE FALL WITH COLDER TEMPERATURES ARRIVING BEHIND THE FRONT.
WE ARE LOOKING AT A 10-15 DEGREE DIFFERENCE BETWEEN TODAY AND
TOMORROW...WITH THE VALLEYS STRUGGLING TO GET ABOVE 65. WEDNESDAY
NIGHT WILL BE DOWNRIGHT COLD IN SOME AREAS. IT LOOKS LIKE MANY
AREAS WILL SEE 20S AND 30S FOR LOWS. THE EXCEPTIONS WILL BE ACROSS
THE SOUTHERN HIGHLANDS WHERE VALLEY TEMPERATURES WILL BOTTOM OUT
IN THE LOW 40S..AND PLACES LIKE STANLEY AND COPPER BASIN WHERE IT
WILL DROP INTO THE TEENS. KEYES
.LONG TERM...THURSDAY THROUGH NEXT TUESDAY. THE END OF THE WEEK
WILL SEE HIGH PRESSURE BUILDING AND SHIFTING EASTWARD OVER IDAHO.
THIS WILL ALLOW FOR A QUICK WARMUP WITH DRY CONDITIONS THROUGH
SATURDAY MORNING. FOR THE TRUE ARRIVAL OF FALL EARLY NEXT
WEEK...THE OVERALL PATTERN SETTLES BACK INTO GENERAL LOW PRESSURE
OVER THE WEST. THERE WILL BE MULTIPLE SYSTEMS IN THE PATTERN THAT
WILL KEEP THE CHANCE OF SHOWERS AROUND WITH A FEW THUNDERSTORMS. KEYES
&&
.AVIATION...TRONG SHOWERS AND THUNDERSTORMS HAVE PASSED TO THE
DOWNWIND SIDE OF ALL AIRDROMES EXCEPT KIDA. -TSRA WILL CONTINUE AND
INCREASE IN COVERAGE AS INSTABILITY DEVELOPS AHEAD OF A COLD FRONT
EXPECTED LATE THIS AFTERNOON/EARLY THIS COMING EVENING...PASSING
THROUGH ALL AIRDROMES BY 18/03Z. -TSRA PROBABILITY BORDERS ON 50
PERCENT FOR KIDA AND KPIH...BUT TEMPO GROUPS NOT ALLOWED BEYOND 6
HOUR POINT. WILL TRY TO USE LATEST HRRR GUIDANCE TO FORECAST A
THUNDERSTORM TIME. FRONTAL PASSAGE IS FROM WEST TO EAST...WITH KIDA
BEING THE LAST. STRONG GRADIENT BEHIND THE FRONT MEANS AN UNUSUALLY
WINDY OVERNIGHT PERIOD TONIGHT. STRONG WIND CONTINUES WED AFTERNOON.
MESSICK
&&
.FIRE WEATHER...ERY UNSTABLE CONDITIONS TODAY WITH A FRONT ARRIVING
IN THE LATE AFTERNOON OVER EASTERN IDAHO. EXPECT A STORMY AND WINDY
DAY...CONTINUING INTO A STORMY AND WINDY NIGHT. FRONT WILL PASS OUT
OF EASTERN IDAHO BY MIDNIGHT TONIGHT...BUT STRONG WINDS WILL
CONTINUE OVERNIGHT AND INCREASE AGAIN TOMORROW AFTERNOON.
THUNDERSTORM ACTIVITY WILL BE LIMITED ON WED TO MAINLY THE TARGHEE
PORTION OF THE CARIBOU-TARGHEE NF. HIGH PRESSURE WILL MOVE IN FOR
THE LAST HALF OF THE WORK WEEK AND FOR AT LEAST A PORTION OF THE
WEEKEND. A STRONG LOW AND COLD FRONT ARE EXPECTED TO REACH IDAHO SAT
NIGHT OR SUN MORNING. NEITHER THE FRONT TODAY NOR THE WEEKEND FRONT
SHOULD BRING MUCH RAINFALL. MAIN ISSUE WILL BE STRONG WIND WITH A
90 KNOT UPPER LEVEL JET OVERHEAD TODAY MIXING DOWNWARD IN THE
UNSTABLE AIR. MESSICK
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM MDT THIS
EVENING IDZ021.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1012 PM CDT WED SEP 18 2013
.DISCUSSION...
336 PM CDT
MAIN CHALLENGES/CONCERNS THIS FORECAST PERIOD ARE WITH SHOWERS AND
THUNDERSTORMS IN THE NEAR TERM...POSSIBLE PERSISTENT
SHOWERS/THUNDERSTORMS OVERNIGHT...AS WELL AS BETTER CHANCES FOR
SHOWERS/THUNDERSTORMS THURSDAY NIGHT INTO FRIDAY MORNING.
CONTINUE TO MONITOR AREA OF SHOWERS AND THUNDERSTORMS ACROSS NORTH
CENTRAL ILLINOIS THAT HAVE CONTINUED TO SLOWLY MOVE EAST TODAY.
LATEST RADAR IMAGERY DEPICTING A CONTINUED DEVELOPING TREND IN
BOTH COVERAGE AND INTENSITY WITH THIS AREA OF PRECIPITATION...AND
EXPECT THIS TO CONTINUE THROUGH THE AFTERNOON AND EARLY EVENING.
MCV IS THE MAIN DRIVING FORCE FOR THESE
SHOWERS/THUNDERSTORMS...WITH LATEST RAP ANALYSIS SHOWING LOWERING
CIN AND AN AXIS OF 1000 J/KG OF SB CAPE EXTENDING INTO NORTHEAST
ILLINOIS AND NORTHWEST INDIANA. ALTHOUGH NOT THE GREATEST...THESE
CONDITIONS WILL BE ENOUGH TO HELP THIS PRECIP TO HOLD TOGETHER
WHILE IT SLOWLY MOVES THROUGH NORTHEAST ILLINOIS THIS AFTERNOON
AND THEN NORTHWEST INDIANA THROUGH EARLY EVENING. ALTHOUGH
WIDESPREAD SEVERE WEATHER IS NOT ANTICIPATED...A PORTION OF THESE
STORMS ALONG THE I-80 CORRIDOR HAVE EXHIBITED SOME STRENGTHENING
TRENDS WITH BRIEF HIGHER WIND SIGNATURES. SO FOR THIS
AFTERNOON/EARLY EVENING...EXPECT ANY OF THE STRONGER STORMS IN
THIS GENERAL AREA TO BE CAPABLE OF PRODUCING SPORADIC WIND GUSTS
TO 50 MPH...CONTINUOUS LIGHTNING...AND BRIEF HEAVY RAINFALL WITH
AN OUTSIDE POSSIBILITY OF AN ISOLATED SEVERE WIND THREAT.
WITH THE DEPARTURE OF THESE THUNDERSTORMS...MOST OF THE CWA SHOULD
OBSERVE A LULL IN PRECIP BEFORE SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE ONCE AGAIN OVER NIGHT. SEVERAL WEAK MID LEVEL FEATURES
WILL CONTINUE TO TRAVERSE CURRENT ZONAL FLOW OVERHEAD...WITH
LOW/MID LEVEL FLOW VEERING OVERNIGHT. AS THIS OCCURS...IT APPEARS
AS BETTER WAA WILL ORIENT ITSELF MORE TOWARDS NORTHERN ILLINOIS.
ALTHOUGH CONFIDENCE IS NOT THE GREATEST FOR COVERAGE TONIGHT...DID
MAINTAIN LOW CHANCE POPS FOR MOST AREAS MAINLY AFTER MIDNIGHT
OWING TO THIS POTENTIAL. WHATEVER DOES DEVELOP SHOULD BE MORE
SCATTERED IN NATURE...AND THEN BEGIN SHIFTING EAST OUT OF THE CWA
WHILE DIMINISHING EARLY THURSDAY MORNING. WITH BROAD SOUTHWESTERLY
FLOW PERSISTING ON THURSDAY AND A FAIRLY MOIST ENVIRONMENT
OVERHEAD...SHOWERS AND THUNDERSTORMS WILL REMAIN POSSIBLE.
ALTHOUGH...CHANCES FOR PRECIPITATION SHOULD REMAIN LOW WITH ONCE
AGAIN ANYTHING THAT DOES DEVELOP REMAINING SCATTERED. WITH THIS
PERSISTENT WAA...CONTINUED WARMUP WILL CONTINUE ON THURSDAY. MADE
LITTLE ADJUSTMENTS TO MAX TEMPS FOR THURSDAY KEEPING UPPER 80S FOR
MOST LOCATIONS...WITH SOME UNCERTAINTIES TO PRECIP AND EVEN CLOUD
COVER REMAINING. IF ENOUGH CLEARING OCCURS...THERMO PROFILES WILL
BE SUPPORTIVE OF SOME LOCATIONS REACHING OR SLIGHTLY EXCEEDING 90
DEGREES.
MAIN FOCUS FOR THUNDERSTORM DEVELOPMENT SHIFTS TOWARDS THE LATE
AFTERNOON AND EARLY EVENING WITH AN APPROACHING TROUGH OF LOW
PRESSURE AND COLD FRONT. AS LARGE VORT MAX DROPS SOUTHEAST ACROSS
THE NORTHERN PLAINS...SEVERAL WAVES OF ENERGY WILL LIFT NORTHEAST
ACROSS THE REGION. THIS WILL HELP TO SHIFT THIS TROUGH/FRONT AS WELL
AS INDUCING SOME FURTHER PRESSURE FALLS OUT AHEAD OF IT. WITH
POTENTIAL FOR PRE FRONTAL TROUGHINESS TO OCCUR TOMORROW
AFTERNOON...SOME GUIDANCE CONTINUES TO DEVELOP PRECIP OUT AHEAD OF
THIS FRONT. ALTHOUGH I FEEL THIS IS A BIT OVERDONE...AND HAVE HELD
BACK ON POPS FOR THURSDAY DURING THE DAY. HAVE EVEN TRENDED
TOWARDS A SLOWER SOLUTION/TREND WITH THIS FRONT/TROUGH WITH BEST
CHANCES FOR SHOWERS/THUNDERSTORMS REMAINING OVER WEST/NORTHWEST
ILLINOIS FOR MOST OF THURSDAY NIGHT. ITS NOT UNTIL EARLY FRIDAY
MORNING THAT THIS FRONT GETS A GOOD SOUTHEAST PUSH WITH BEST
FORCING MOVING OVERHEAD. GOOD SWATH OF PRECIP SHOULD SHIFT
SOUTHEAST ACROSS THE ENTIRE CWA THROUGH MID DAY FRIDAY...WITH THIS
PRECIP THEN EXPECTED TO SHIFT OUT OF THE AREA THROUGH THE
AFTERNOON. IT DOES APPEAR AS IF THE STRONGER STORMS SHOULD REMAIN
JUST WEST OF THE CWA...BUT WITH SOME POTENTIAL FOR THEM TO REACH
THE FAR WESTERN CWA THURSDAY EVENING/NIGHT. IF INSTABILITY CAN
INCREASE ON FRIDAY...THERE IS THE POTENTIAL FOR A LINGERING STRONG
TO SEVERE THREAT ACROSS THE CWA BEFORE THE STORMS SHIFT OUT OF THE
CWA.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* LOW CHANCE FOR ADDITIONAL SHRA/TSRA LATE TONIGHT/THURSDAY MORNING.
* GUSTY SOUTH-SOUTHWEST WINDS THURSDAY.
KJB
//DISCUSSION...UPDATED 03Z...
THERE CONTINUES TO BE A LOW THREAT FOR ADDITIONAL SCATTERED
THUNDERSTORM DEVELOPMENT ACROSS THE AREA OVERNIGHT. A WARM FRONT
IS CURRENTLY APPROACHING THE AREA AND WARM MOIST AIR CONTINUES TO
LIFT OVER THIS FRONT VIA A LOW LEVEL JET...AND THIS COULD LEAD TO
ADDITIONAL STORMS OVERNIGHT. HOWEVER...CONFIDENCE REMAINS LOW
REGARDING THE EXTENT OF ACTIVITY...BUT RATHER THAN GETTING RID OF
THE PROB 30 GROUP FOR THE UPDATE...I CHOOSE TO ADD IT AS A TEMPO
GROUP.
//DISCUSSION...UPDATED 00Z...
THINGS SHOULD BEGIN QUIETING DOWN NOW FOR MUCH OF THE EVENING. THE
LAST BATCH OF THUNDERSTORMS...CURRENTLY ASSOCIATED WITH THE ENHANCED
FORCING FOR ASCENT WITH THE MID LEVEL VORT/MCV...IS MOVING ACROSS
NORTHEASTERN ILLINOIS. ONCE THIS ACTIVITY MOVES EAST EARLY THIS
EVENING...SEVERAL HOURS OF QUITE WEATHER LOOKS TO BE ON TAP FOR THE
AREA. THE WINDS ARE BIT DISTURBED FROM THE CURRENT CONVECTIVE
ACTIVITY...BUT EXPECT WINDS TO QUICKLY COME BACK OUT OF THE SOUTH
WITHIN THE NEXT HOUR OR TWO.
THERE IS STILL A CHANCE THAT ADDITIONAL THUNDERSTORMS COULD DEVELOP
LATER TONIGHT AS WE REMAIN IN AN UNSETTLED MID/UPPER LEVEL FLOW
PATTERN AND A WARM FRONT LIFTS NORTH ACROSS THE AREA.
HOWEVER...CONFIDENCE STILL REMAINS LOW...SO I HAVE CONTINUED THE
PROB 30 GROUP FOR LATE TONIGHT AFTER 09 UTC.
SOUTH-SOUTHWEST WINDS WILL BE FAIRLY STRONG TOMORROW...WITH GUSTS UP
AROUND 20 KT THROUGH THE DAY AS LOW PRESSURE MOVES ACROSS THE UPPER
MIDWEST. CHANCES FOR CONVECTION WILL INCREASE THURSDAY NIGHT INTO
FRIDAY MORNING AS A COLD FRONT APPROACHES THE AREA.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* LOW-MEDIUM CONFIDENCE ON SHRA/TSRA THURSDAY MORNING.
* MODERATE CONFIDENCE IN WINDS ON THURSDAY.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...SHRA/TSRA LIKELY THROUGH LATE AFTERNOON...SHRA POSSIBLY
LINGERING INTO THE EVENING. MVFR POSSIBLE. WIND SHIFT FROM SWLY TO
NWLY IN THE AFTERNOON.
SATURDAY THROUGH TUESDAY...VFR. WX NIL.
KJB
&&
.MARINE...
256 PM CDT
AN AREA OF LOW PRESSURE CENTERED OVER THE DAKOTAS IS TO WEAKEN
SLIGHTLY AS IT TRACKS NORTHEAST TO SOUTHERN CANADA BY MIDDAY
THURSDAY. THE LOW THEN DEEPENS FRIDAY AND MOVES ACROSS JAMES BAY.
AN ASSOCIATED COLD FRONT WILL MOVE SOUTHEASTWARD AND ACROSS LAKE
MI DURING FRIDAY SHIFTING SOUTH AND SOUTHWESTERLY WINDS TO OUT OF
THE WEST AND NORTHWEST AND INCREASING TO STRONG BREEZES. AS LARGE
HIGH PRESSURE BUILDS SOUTHEASTWARD ACROSS THE WESTERN GREAT LAKES
FRIDAY THROUGH SUNDAY WINDS WILL GRADUALLY RELAX AS THEY VEER
THROUGH NORTH AND EAST TO SOUTHEAST.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
642 PM CDT WED SEP 18 2013
.DISCUSSION...
336 PM CDT
MAIN CHALLENGES/CONCERNS THIS FORECAST PERIOD ARE WITH SHOWERS AND
THUNDERSTORMS IN THE NEAR TERM...POSSIBLE PERSISTENT
SHOWERS/THUNDERSTORMS OVERNIGHT...AS WELL AS BETTER CHANCES FOR
SHOWERS/THUNDERSTORMS THURSDAY NIGHT INTO FRIDAY MORNING.
CONTINUE TO MONITOR AREA OF SHOWERS AND THUNDERSTORMS ACROSS NORTH
CENTRAL ILLINOIS THAT HAVE CONTINUED TO SLOWLY MOVE EAST TODAY.
LATEST RADAR IMAGERY DEPICTING A CONTINUED DEVELOPING TREND IN
BOTH COVERAGE AND INTENSITY WITH THIS AREA OF PRECIPITATION...AND
EXPECT THIS TO CONTINUE THROUGH THE AFTERNOON AND EARLY EVENING.
MCV IS THE MAIN DRIVING FORCE FOR THESE
SHOWERS/THUNDERSTORMS...WITH LATEST RAP ANALYSIS SHOWING LOWERING
CIN AND AN AXIS OF 1000 J/KG OF SB CAPE EXTENDING INTO NORTHEAST
ILLINOIS AND NORTHWEST INDIANA. ALTHOUGH NOT THE GREATEST...THESE
CONDITIONS WILL BE ENOUGH TO HELP THIS PRECIP TO HOLD TOGETHER
WHILE IT SLOWLY MOVES THROUGH NORTHEAST ILLINOIS THIS AFTERNOON
AND THEN NORTHWEST INDIANA THROUGH EARLY EVENING. ALTHOUGH
WIDESPREAD SEVERE WEATHER IS NOT ANTICIPATED...A PORTION OF THESE
STORMS ALONG THE I-80 CORRIDOR HAVE EXHIBITED SOME STRENGTHENING
TRENDS WITH BRIEF HIGHER WIND SIGNATURES. SO FOR THIS
AFTERNOON/EARLY EVENING...EXPECT ANY OF THE STRONGER STORMS IN
THIS GENERAL AREA TO BE CAPABLE OF PRODUCING SPORADIC WIND GUSTS
TO 50 MPH...CONTINUOUS LIGHTNING...AND BRIEF HEAVY RAINFALL WITH
AN OUTSIDE POSSIBILITY OF AN ISOLATED SEVERE WIND THREAT.
WITH THE DEPARTURE OF THESE THUNDERSTORMS...MOST OF THE CWA SHOULD
OBSERVE A LULL IN PRECIP BEFORE SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE ONCE AGAIN OVER NIGHT. SEVERAL WEAK MID LEVEL FEATURES
WILL CONTINUE TO TRAVERSE CURRENT ZONAL FLOW OVERHEAD...WITH
LOW/MID LEVEL FLOW VEERING OVERNIGHT. AS THIS OCCURS...IT APPEARS
AS BETTER WAA WILL ORIENT ITSELF MORE TOWARDS NORTHERN ILLINOIS.
ALTHOUGH CONFIDENCE IS NOT THE GREATEST FOR COVERAGE TONIGHT...DID
MAINTAIN LOW CHANCE POPS FOR MOST AREAS MAINLY AFTER MIDNIGHT
OWING TO THIS POTENTIAL. WHATEVER DOES DEVELOP SHOULD BE MORE
SCATTERED IN NATURE...AND THEN BEGIN SHIFTING EAST OUT OF THE CWA
WHILE DIMINISHING EARLY THURSDAY MORNING. WITH BROAD SOUTHWESTERLY
FLOW PERSISTING ON THURSDAY AND A FAIRLY MOIST ENVIRONMENT
OVERHEAD...SHOWERS AND THUNDERSTORMS WILL REMAIN POSSIBLE.
ALTHOUGH...CHANCES FOR PRECIPITATION SHOULD REMAIN LOW WITH ONCE
AGAIN ANYTHING THAT DOES DEVELOP REMAINING SCATTERED. WITH THIS
PERSISTENT WAA...CONTINUED WARMUP WILL CONTINUE ON THURSDAY. MADE
LITTLE ADJUSTMENTS TO MAX TEMPS FOR THURSDAY KEEPING UPPER 80S FOR
MOST LOCATIONS...WITH SOME UNCERTAINTIES TO PRECIP AND EVEN CLOUD
COVER REMAINING. IF ENOUGH CLEARING OCCURS...THERMO PROFILES WILL
BE SUPPORTIVE OF SOME LOCATIONS REACHING OR SLIGHTLY EXCEEDING 90
DEGREES.
MAIN FOCUS FOR THUNDERSTORM DEVELOPMENT SHIFTS TOWARDS THE LATE
AFTERNOON AND EARLY EVENING WITH AN APPROACHING TROUGH OF LOW
PRESSURE AND COLD FRONT. AS LARGE VORT MAX DROPS SOUTHEAST ACROSS
THE NORTHERN PLAINS...SEVERAL WAVES OF ENERGY WILL LIFT NORTHEAST
ACROSS THE REGION. THIS WILL HELP TO SHIFT THIS TROUGH/FRONT AS WELL
AS INDUCING SOME FURTHER PRESSURE FALLS OUT AHEAD OF IT. WITH
POTENTIAL FOR PRE FRONTAL TROUGHINESS TO OCCUR TOMORROW
AFTERNOON...SOME GUIDANCE CONTINUES TO DEVELOP PRECIP OUT AHEAD OF
THIS FRONT. ALTHOUGH I FEEL THIS IS A BIT OVERDONE...AND HAVE HELD
BACK ON POPS FOR THURSDAY DURING THE DAY. HAVE EVEN TRENDED
TOWARDS A SLOWER SOLUTION/TREND WITH THIS FRONT/TROUGH WITH BEST
CHANCES FOR SHOWERS/THUNDERSTORMS REMAINING OVER WEST/NORTHWEST
ILLINOIS FOR MOST OF THURSDAY NIGHT. ITS NOT UNTIL EARLY FRIDAY
MORNING THAT THIS FRONT GETS A GOOD SOUTHEAST PUSH WITH BEST
FORCING MOVING OVERHEAD. GOOD SWATH OF PRECIP SHOULD SHIFT
SOUTHEAST ACROSS THE ENTIRE CWA THROUGH MID DAY FRIDAY...WITH THIS
PRECIP THEN EXPECTED TO SHIFT OUT OF THE AREA THROUGH THE
AFTERNOON. IT DOES APPEAR AS IF THE STRONGER STORMS SHOULD REMAIN
JUST WEST OF THE CWA...BUT WITH SOME POTENTIAL FOR THEM TO REACH
THE FAR WESTERN CWA THURSDAY EVENING/NIGHT. IF INSTABILITY CAN
INCREASE ON FRIDAY...THERE IS THE POTENTIAL FOR A LINGERING STRONG
TO SEVERE THREAT ACROSS THE CWA BEFORE THE STORMS SHIFT OUT OF THE
CWA.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* CURRENT TSRA MOVING OUT OF THE AREA BY 0030 UTC.
* LOW CHANCE FOR ADDITIONAL SHRA/TSRA LATE TONIGHT/THURSDAY MORNING.
* GUSTY SOUTH-SOUTHWEST WINDS THURSDAY.
KJB
//DISCUSSION...UPDATED 00Z...
THINGS SHOULD BEGIN QUIETING DOWN NOW FOR MUCH OF THE EVENING. THE
LAST BATCH OF THUNDERSTORMS...CURRENTLY ASSOCIATED WITH THE ENHANCED
FORCING FOR ASCENT WITH THE MID LEVEL VORT/MCV...IS MOVING ACROSS
NORTHEASTERN ILLINOIS. ONCE THIS ACTIVITY MOVES EAST EARLY THIS
EVENING...SEVERAL HOURS OF QUITE WEATHER LOOKS TO BE ON TAP FOR THE
AREA. THE WINDS ARE BIT DISTURBED FROM THE CURRENT CONVECTIVE
ACTIVITY...BUT EXPECT WINDS TO QUICKLY COME BACK OUT OF THE SOUTH
WITHIN THE NEXT HOUR OR TWO.
THERE IS STILL A CHANCE THAT ADDITIONAL THUNDERSTORMS COULD DEVELOP
LATER TONIGHT AS WE REMAIN IN AN UNSETTLED MID/UPPER LEVEL FLOW
PATTERN AND A WARM FRONT LIFTS NORTH ACROSS THE AREA.
HOWEVER...CONFIDENCE STILL REMAINS LOW...SO I HAVE CONTINUED THE
PROB 30 GROUP FOR LATE TONIGHT AFTER 09 UTC.
SOUTH-SOUTHWEST WINDS WILL BE FAIRLY STRONG TOMORROW...WITH GUSTS UP
AROUND 20 KT THROUGH THE DAY AS LOW PRESSURE MOVES ACROSS THE UPPER
MIDWEST. CHANCES FOR CONVECTION WILL INCREASE THURSDAY NIGHT INTO
FRIDAY MORNING AS A COLD FRONT APPROACHES THE AREA.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* LOW CONFIDENCE ON SHRA/TSRA THURSDAY MORNING.
* MODERATE CONFIDENCE IN WINDS ON THURSDAY.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...SHRA/TSRA LIKELY THROUGH LATE AFTERNOON...SHRA POSSIBLY
LINGERING INTO THE EVENING. MVFR POSSIBLE. WIND SHIFT FROM SWLY TO
NWLY IN THE AFTERNOON.
SATURDAY THROUGH TUESDAY...VFR. WX NIL.
KJB
&&
.MARINE...
256 PM CDT
AN AREA OF LOW PRESSURE CENTERED OVER THE DAKOTAS IS TO WEAKEN
SLIGHTLY AS IT TRACKS NORTHEAST TO SOUTHERN CANADA BY MIDDAY
THURSDAY. THE LOW THEN DEEPENS FRIDAY AND MOVES ACROSS JAMES BAY.
AN ASSOCIATED COLD FRONT WILL MOVE SOUTHEASTWARD AND ACROSS LAKE
MI DURING FRIDAY SHIFTING SOUTH AND SOUTHWESTERLY WINDS TO OUT OF
THE WEST AND NORTHWEST AND INCREASING TO STRONG BREEZES. AS LARGE
HIGH PRESSURE BUILDS SOUTHEASTWARD ACROSS THE WESTERN GREAT LAKES
FRIDAY THROUGH SUNDAY WINDS WILL GRADUALLY RELAX AS THEY VEER
THROUGH NORTH AND EAST TO SOUTHEAST.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1014 PM EDT WED SEP 18 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 358 PM EDT WED SEP 18 2013
A BROAD UPPER LEVEL RIDGE TO OUR SOUTH IS BEING ROUNDED BY VERY
WEAK AND VERY SUBTLE UPPER LEVEL WAVES...POORLY RESOLVED BY
GUIDANCE. THESE WEAK WAVES MAY BE ABLE TO SPARK A SHOWER OR STORM
AT TIMES THROUGH LATE THURSDAY NIGHT INTO FRIDAY NIGHT...WHEN THE
MAIN FRONTAL SYSTEM WILL PUSH THROUGH THE AREA AND BRING A MORE
SUBSTANTIAL OPPORTUNITY FOR STORMS TO THE AREA BEFORE DRY AND
COOLER CONDITIONS RETURN FOR THE REMAINDER OF THE FORECAST PERIOD.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 946 PM EDT WED SEP 18 2013
RADAR LOOP SHOWS SOME STORMS IN NORTHWEST INDIANA WITH A LITTLE
SHOWER ALSO OVER NORTHERN CARROLL COUNTY. THE LARGER AREA OF
STORMS IS MOVING SOUTHEAST. LOOKING AT HRRR MODEL OUTPUT IT
APPEARS THAT THIS WILL WEAKEN AS IT HEADS THIS WAY SIMILAR TO THE
ECHOES THAT ARE NOW ONLY A BRIEF SHOWER. STILL IT LOOKS POSSIBLE
THAT STORMS COULD REACH THE NORTHERN COUNTIES OF THE AREA OVER THE
NEXT FEW HOURS AND THUS WENT WITH A SLIGHT TO LOW END CHANCE THERE
DURING THIS TIME. ALSO SEEING SOME LIGHT RAIN OVER CENTRAL
ILLINOIS PROMPTED BY A WEAK UPPER WAVE AND SOME ISENTROPIC LIFT
AND THIS COULD MOVE INTO THE AREA AFTER 6Z...SO WENT WITH A SLIGHT
CHANCE ACROSS ALL OF CENTRAL INDIANA THEN. THIS SHOULD ALSO COVER
SOME REDEVELOPMENT OVER THE NORTHEASTERN COUNTIES THAT THE HRRR IS
SHOWING...ALTHOUGH CONFIDENCE IN THIS SOLUTION IS LOW AND THUS NO
HIGHER THAN 20 POPS WILL BE USED DURING THAT TIME.
GOING LOW TEMPERATURES IN THE MIDDLE 60S LOOK GOOD BASED ON
EXPECTED CLOUD COVER AND CURRENT TEMPERATURES.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
ISSUED AT 358 PM EDT WED SEP 18 2013
MAY SEE SOME SHOWERS OR STORMS DEVELOP FROM MIDDAY ONWARD
TOMORROW...AGAIN NO MORE THAN SCATTERED IN NATURE. HIGHER POPS ARE
ONLY MERITED FRIDAY INTO FRIDAY NIGHT AS THE FRONT FINALLY PUSHES
THROUGH THE AREA. SPC SEE TEXT OUTLOOK DAY 3 APPEARS REASONABLE
GIVEN THE TIME OF DAY THE FRONT IS EXPECTED...BUT INSTABILITY AND
SHEAR ARE MODEST AT BEST AND DO NOT EXPECT MUCH MORE THAN ISOLATED
SEVERE IF THAT.
ON TEMPS...CONSENSUS NUMBERS LOOKED OK THROUGHOUT GIVEN EXPECTED
THICKNESSES AND PRECIP COVERAGE...EXCEPT FOR SATURDAY WHERE A
WARMER MOS BLEND WAS PREFERRED WITH SKIES LIKELY TO CLEAR AND
AMPLE SUN EXPECTED.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
ISSUED AT 220 PM EDT WED SEP 18 2013
DRY FORECAST THIS PERIOD WITH SEASONABLE TEMPERATURES.
GFS AND ECMWF DEPICT A CUT OFF UPPER LOW MOVING THROUGH THE
APPALACHIANS EARLY IN THE PERIOD WHILE RIDGING ALOFT AND STRONG
SUBSIDENCE OVER THE MISSISSIPPI RIVER VALLEY PROVIDES A NORTHERLY
FLOW OF AIR AS IT SLOWLY BUILDS EAST DURING THE PERIOD.
AS THE RIDGE MOVES EAST OVER INDIANA BY THE MIDDLE OF NEXT
WEEK...TEMPS WILL SLOWLY MODERATE TO SLIGHTLY ABOVE NORMAL AS
RETURN FLOW BEGINS.
&&
.AVIATION /DISCUSSION FOR THE 190000Z TAFS/...
ISSUED AT 1013 PM EDT WED SEP 18 2013
0215Z UPDATE...VERY LITTLE CHANGE NEEDED TO THE TAFS ATTM. PREV
DISC FOLLOWS.
VFR CONDITIONS EXPECTED THIS EVENING. MVFR CONDITIONS WILL BE
POSSIBLE LATE TONIGHT EARLY THU MORNING. A RETURN TO VFR IS EXPECTED
LATE ON THURSDAY MORNING.
AS HEATING IS LOST THIS EVENING...OVERALL COVERAGE OF
PRECIPITATION TO THE WEST SHOULD DIMINISH. MODELS HINT AT LOWERING
CIGS AND VISIBILITIES DIURNALLY TONIGHT AS HIGH DEW POINTS AND
DIURNAL COOLING IS ONGOING. MODELS ONCE AGAIN HINT AT ANOTHER BIT
OF LIFT PUSHING THROUGH THE AREA ON LATE THURSDAY AFTERNOON...HOWEVER...CONFIDENCE
IN THIS WEAK FEATURES REMAIN LOW AND WILL STICK WITH VFR AND VCSH
ATTM.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...CP
SHORT TERM...NIELD
LONG TERM....PUMA
AVIATION...SMF
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
953 PM EDT WED SEP 18 2013
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 358 PM EDT WED SEP 18 2013
A BROAD UPPER LEVEL RIDGE TO OUR SOUTH IS BEING ROUNDED BY VERY
WEAK AND VERY SUBTLE UPPER LEVEL WAVES...POORLY RESOLVED BY
GUIDANCE. THESE WEAK WAVES MAY BE ABLE TO SPARK A SHOWER OR STORM
AT TIMES THROUGH LATE THURSDAY NIGHT INTO FRIDAY NIGHT...WHEN THE
MAIN FRONTAL SYSTEM WILL PUSH THROUGH THE AREA AND BRING A MORE
SUBSTANTIAL OPPORTUNITY FOR STORMS TO THE AREA BEFORE DRY AND
COOLER CONDITIONS RETURN FOR THE REMAINDER OF THE FORECAST PERIOD.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 946 PM EDT WED SEP 18 2013
RADAR LOOP SHOWS SOME STORMS IN NORTHWEST INDIANA WITH A LITTLE
SHOWER ALSO OVER NORTHERN CARROLL COUNTY. THE LARGER AREA OF
STORMS IS MOVING SOUTHEAST. LOOKING AT HRRR MODEL OUTPUT IT
APPEARS THAT THIS WILL WEAKEN AS IT HEADS THIS WAY SIMILAR TO THE
ECHOES THAT ARE NOW ONLY A BRIEF SHOWER. STILL IT LOOKS POSSIBLE
THAT STORMS COULD REACH THE NORTHERN COUNTIES OF THE AREA OVER THE
NEXT FEW HOURS AND THUS WENT WITH A SLIGHT TO LOW END CHANCE THERE
DURING THIS TIME. ALSO SEEING SOME LIGHT RAIN OVER CENTRAL
ILLINOIS PROMPTED BY A WEAK UPPER WAVE AND SOME ISENTROPIC LIFT
AND THIS COULD MOVE INTO THE AREA AFTER 6Z...SO WENT WITH A SLIGHT
CHANCE ACROSS ALL OF CENTRAL INDIANA THEN. THIS SHOULD ALSO COVER
SOME REDEVELOPMENT OVER THE NORTHEASTERN COUNTIES THAT THE HRRR IS
SHOWING...ALTHOUGH CONFIDENCE IN THIS SOLUTION IS LOW AND THUS NO
HIGHER THAN 20 POPS WILL BE USED DURING THAT TIME.
GOING LOW TEMPERATURES IN THE MIDDLE 60S LOOK GOOD BASED ON
EXPECTED CLOUD COVER AND CURRENT TEMPERATURES.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
ISSUED AT 358 PM EDT WED SEP 18 2013
MAY SEE SOME SHOWERS OR STORMS DEVELOP FROM MIDDAY ONWARD
TOMORROW...AGAIN NO MORE THAN SCATTERED IN NATURE. HIGHER POPS ARE
ONLY MERITED FRIDAY INTO FRIDAY NIGHT AS THE FRONT FINALLY PUSHES
THROUGH THE AREA. SPC SEE TEXT OUTLOOK DAY 3 APPEARS REASONABLE
GIVEN THE TIME OF DAY THE FRONT IS EXPECTED...BUT INSTABILITY AND
SHEAR ARE MODEST AT BEST AND DO NOT EXPECT MUCH MORE THAN ISOLATED
SEVERE IF THAT.
ON TEMPS...CONSENSUS NUMBERS LOOKED OK THROUGHOUT GIVEN EXPECTED
THICKNESSES AND PRECIP COVERAGE...EXCEPT FOR SATURDAY WHERE A
WARMER MOS BLEND WAS PREFERRED WITH SKIES LIKELY TO CLEAR AND
AMPLE SUN EXPECTED.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
ISSUED AT 220 PM EDT WED SEP 18 2013
DRY FORECAST THIS PERIOD WITH SEASONABLE TEMPERATURES.
GFS AND ECMWF DEPICT A CUT OFF UPPER LOW MOVING THROUGH THE
APPALACHIANS EARLY IN THE PERIOD WHILE RIDGING ALOFT AND STRONG
SUBSIDENCE OVER THE MISSISSIPPI RIVER VALLEY PROVIDES A NORTHERLY
FLOW OF AIR AS IT SLOWLY BUILDS EAST DURING THE PERIOD.
AS THE RIDGE MOVES EAST OVER INDIANA BY THE MIDDLE OF NEXT
WEEK...TEMPS WILL SLOWLY MODERATE TO SLIGHTLY ABOVE NORMAL AS
RETURN FLOW BEGINS.
&&
.AVIATION /DISCUSSION FOR THE 190000Z TAFS/...
ISSUED AT 711 PM EDT WED SEP 18 2013
VFR CONDITIONS EXPECTED THIS EVENING. MVFR CONDITIONS WILL BE
POSSIBLE LATE TONIGHT EARLY THU MORNING. A RETURN TO VFR IS EXPECTED
LATE ON THURSDAY MORNING.
AS HEATING IS LOST THIS EVENING...OVERALL COVERAGE OF
PRECIPITATION TO THE WEST SHOULD DIMINISH. MODELS HINT AT LOWERING
CIGS AND VISIBILITIES DIURNALLY TONIGHT AS HIGH DEW POINTS AND
DIURNAL COOLING IS ONGOING. MODELS ONCE AGAIN HINT AT ANOTHER BIT
OF LIFT PUSHING THROUGH THE AREA ON LATE THURSDAY AFTERNOON...HOWEVER...CONFIDENCE
IN THIS WEAK FEATURES REMAIN LOW AND WILL STICK WITH VFR AND VCSH
ATTM.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...CP
SHORT TERM...NIELD
LONG TERM....PUMA
AVIATION...SMF
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AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
855 PM CDT WED SEP 18 2013
.UPDATE...
ISSUED AT 847 PM CDT WED SEP 18 2013
AN UPDATE WAS JUST SENT TO INCREASE POPS OVER THE NORTH HALF OF
THE AREA AFTER MIDNIGHT. LLJ PROGGED TO STRENGTHEN TO 40+KTS LATE
TONIGHT AND IS POINTED AT NORTHEAST IOWA DURING THE EARLY MORNING
HOURS. SATELLITE IMAGERY IS SHOWING AN AREA OF MID CLOUDS DRIFTING EAST
THROUGH NORTH CENTRAL IA AND THEY SHOULD BE OVER THE NE QUARTER
OF THE STATE BY MIDNIGHT...WHERE THE NOSE OF THE LLJ IS AIMED. THE
PAST SEVERAL RUNS OF THE HRRR HAVE BEEN CONSISTENTLY DEVELOPING
CONVECTION IN THE SAME AREA. GIVEN THESE FACTORS THERE WAS ENOUGH
CONFIDENCE TO INCREASE POPS INTO THE CHANCE CATEGORY BETWEEN 06Z
AND 12Z.
DLF
&&
.SYNOPSIS...
ISSUED AT 310 PM CDT WED SEP 18 2013
12Z UA ANALYSIS HAD AN 850MB LOW NEAR KBIS WITH A DEVELOPING WARM
FRONT RUNNING SOUTHEAST TO KSTL. A LLJ RAN FROM WEST TEXAS INTO
SOUTHWEST IOWA AND DEW POINTS WERE IN THE MID TEENS FROM MEXICO INTO
SOUTHERN MINNESOTA. SATELLITE/RADAR TRENDS SHOW THE SMALL COMPLEX OF
STORMS MOVING INTO NORTHEAST IOWA WITH GENERALLY CLEAR SKIES ACROSS
THE PLAINS AND IOWA.
18Z SFC ANALYSIS HAS A LOW NEAR KPIR WITH A WARM FRONT RUNNING
SOUTHEAST TO NEAR KMLI AND THEN SOUTH TO NEAR K3LF. RAIN COOLED AIR
REMAINED ACROSS NORTHEAST IOWA AND NORTHWEST ILLINOIS. DEW POINTS
WERE IN THE 60S ACROSS THE MIDWEST WITH POCKETS OF 70S IN THE
SOUTHERN PLAINS.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 310 PM CDT WED SEP 18 2013
SATELLITE TRENDS INDICATE LITTLE IN THE WAY OF NEW CLOUDS HAVE
FORMED DURING THE AFTERNOON SO THE THREAT OF NEW CONVECTION PRIOR TO
SUNSET IS VERY LOW.
THE MCS AND LIFT TOOLS ARE SUGGESTING SOME ISOLATED WEAK CONVECTION
MAY DEVELOP OVER THE AREA BY LATE EVENING AND MOVE EAST.
HOWEVER...THE BETTER FORCING/MOISTURE IS WEST OF THE AREA. THE MCS
AND LIFT TOOLS ARE SUGGESTING ANOTHER STORM COMPLEX DEVELOPING ALONG
THE IA/MO BORDER LATE TONIGHT AND POSSIBLY ARRIVING IN THE WESTERN
CWFA AROUND SUNRISE THURSDAY. THUS MOST OF THE AREA SHOULD SEE DRY
CONDITIONS TONIGHT.
IF THE STORM COMPLEX DEVELOPS AS SUGGESTED ALONG THE IA/MO
BORDER...THEN THIS COMPLEX WOULD MOVE ACROSS THE WESTERN HALF OF THE
CWFA DURING THE MORNING. CLOUD COVER/PRECIPITATION MAY MAKE IT
DIFFICULT TO ACHIEVE HIGHS IN THE MID AND UPPER 80S THURSDAY.
NEW CONVECTION IS EXPECTED TO DEVELOP THURSDAY AFTERNOON AHEAD OF
THE APPROACHING COLD FRONT. MOISTURE LEVELS IN THE ATMOSPHERE ARE
PROJECTED TO BE QUITE HIGH UP INTO THE MID LEVELS. THUS THE
POTENTIAL FOR ANY SEVERE STORMS APPEARS TO BE LOW. ..08..
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 310 PM CDT WED SEP 18 2013
MODERATE TO HEAVY RAIN EVENT THURSDAY NIGHT...THEN SEASONABLY COOL.
OVERVIEW...INITIALIZATION AND VERIFICATION AVERAGE WITH MOST SOLUTIONS
UNDERPLAYING MOISTURE IN CENTRAL PLAINS AND SW MONSOON PLUME. PACIFIC
ENERGY IS ALSO UNDERPLAYED WITH 10 TO 20 METER HEIGHT FALLS UNDERDONE.
THIS SHOWS UP IN SURFACE PRESSURE FIELDS. VERIFICATION AT 18Z SUPPORTS
FORCING OF HI-RES ECMWF/UKMET AND NAM-WRF WITH HI- RES ECMWF CLOSEST
ON MOISTURE FLUX WITH COOL FRONT PASSING THURSDAY NIGHT. THEN...EARLY
FALL HIGH PRESSURE TO BRING SEVERAL DAYS OF NICE LATE SEPTEMBER WEATHER
WITH LOW HUMIDITY.
THURSDAY NIGHT...STRAIGHTFORWARD FORECAST. PW/S OF 1.5" OF DEEP MOISTURE
AHEAD OF DEEP SURFACE AND UPPER LEVEL TROUGH TO BRING A LARGE SWATH
OF SHOWERS AND THUNDERSTORMS. LITTLE OR NO SURFACE WAVE SUGGESTED AT
THIS TIME...LOCAL TOOLS INDICATE ALMOST ALL THE AREA TO PICK UP .5 TO
LOCALLY NEAR 1.5 INCHES OF RAIN. WENT WITH 80-90 POPS WITH FRONT PASSING
BETWEEN MIDNIGHT AND 7 AM. DEEP MOISTURE...OVERNIGHT FORCING AND HIGH
FREEZING LEVELS DO NOT SUPPORT A SEVERE RISK AT THIS TIME WITH STRONGEST
STORMS PRODUCING MAYBE 30-40 MPH WINDS. LATER SHIFTS WILL NEED TO REASSESS
AS NAM- WRF IS TOO UNSTABLE IN BL AS HAS BEEN MORE OFTEN THE CASE THIS
WARM SEASON. NOTE: IF A WAVE FORMS...LOCALLY 2+ INCH AMOUNTS WILL BE
POSSIBLE.
FRIDAY...KEPT MORNING POPS EAST SECTIONS WITH CLEARING BY MID DAY AND
BREEZING NW WINDS OF 10-20+ MPH. HIGHS MOSTLY 70-75F FOR A NICE DAY.
FRIDAY NIGHT THROUGH WEDNESDAY...MOSTLY FAIR AND SLIGHTLY BELOW NORMAL
TEMPERATURES AS CANADIAN HIGH PRESSURE DOMINATES. HIGHS GENERALLY UPPER
60S TO MIDDLE 70S WITH LOWS 45 TO 55 DEGREES. GOOD WEATHER FOR MOST
OUTDOOR ACTIVITIES. ANOTHER PROMISING RAIN EVENT POSSIBLE BY LATE IN
THE WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 632 PM CDT WED SEP 18 2013
THE MAIN CONCERN WILL BE THE THUNDERSTORM POTENTIAL OVERNIGHT.
THERE ARE STILL INDICATIONS OF A THUNDERSTORM COMPLEX DEVELOPING
TO OUR WEST LATE TONIGHT AND MOVING EAST THROUGH THE AREA THURSDAY
MORNING. IT APPEARS THE BETTER FORCING WILL BE NORTH OF I80 SO
LIMITED THE MENTION OF THUNDER TO THE CID AND DBQ TAFS BETWEEN 10Z
AND 14Z. OTHERWISE EXPECT MAINLY VFR CONDITIONS OVERNIGHT
THURSDAY. A COLD FRONT WILL BE APPROACHING THE AREA THURSDAY
AFTERNOON. THUNDERSTORMS AHEAD OF THE FRONT COULD REACH CID AND
DBQ AS EARLY AS LATE THURSDAY AFTERNOON. IFR/MVFR CONDITIONS WOULD
ACCOMPANY THE STORMS. ALSO SOUTHWEST WINDS AHEAD OF THE FRONT WILL
GUST TO 20 TO 25KTS DURING THE AFTERNOON.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...DLF
SYNOPSIS...08
SHORT TERM...08
LONG TERM...NICHOLS
AVIATION...DLF
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1132 PM CDT MON SEP 16 2013
.UPDATE...
ISSUED AT 1130 PM CDT MON SEP 16 2013
MIDWEST DOPPLER RADARS WERE INDICATING AN AREA OF INCREASING
SHOWERS ALONG THE MO RIVER VALLEY FROM SE NEB/SW IA AND INTO EXTREME
NW MO LATE THIS EVENING. WARM AIR ADVECTION WAS KICKING IN AS THE
NOCTURNAL LOW LEVEL JET INTENSIFIES IN THE SOUTHERN PLAINS. ACROSS
THE DVN CWA THE CIRRUS SHIELD CONTINUED TO EXPAND NORTHEASTWARD AS
THE GREAT LAKES HIGH PRESSURE SYSTEM SLOWLY SHIFTS EAST. TEMPERATURES
HAVE ALREADY DIPPED INTO THE UPPER 40S IN NW IL WITH MID TO UPPER
50S COMMON ELSEWHERE.
THE 00Z SUBJECTIVE UPPER AIR ANALYSIS INDICATED A VERY DRY AIRMASS
FROM ABOUT THE MS RIVER VALLEY EASTWARD INTO THE GREAT LAKES. 850
MB DEWPOINTS WERE -10C AT KDVN...-18C AT KMPX...AND -23C AT KDTX.
WEST OF THE RIDGE AXIS COPIOUS MOISTURE WAS FOUND IN THE PLAINS.
850 MB DEWPOINTS WERE 14C AT KTOP AND IN THE RANGE OF 14 TO 17C
FROM SOUTHERN/WESTERN TX INTO OK. PRECIPITABLE WATERS WERE 150 TO
180 PERCENT OF NORMAL FOR MID SEPTEMBER IN THE PLAINS.
THE RAPID REFRESH/NAM THIS EVENING BRING IN A FEW LIGHT SHOWERS OR
SPRINKLES INTO OUR FAR SW CWA TOWARDS MORNING SO HAVE LEFT SMALL
POPS AS IS. HAVE ALREADY ADJUSTED SKY GRIDS BUT HAVE LEFT TEMPERATURES
ALONE FOR NOW.
UPDATE ISSUED AT 630 PM CDT MON SEP 16 2013
CIRRUS SHIELD CONTINUES TO SPILL INTO THE SOUTHWEST HALF OF THE
CWA BUT THINS AS IT RUNS INTO THE DRY AIR FARTHER TO THE NORTHEAST...
WITH HIGH PRESSURE SITUATED ACROSS THE GREAT LAKES REGION. WILL
MONITOR THIS EVENING THE TEMPERATURE AND CLOUD TRENDS AND ADJUST
IF NEEDED.
&&
.SYNOPSIS...
ISSUED AT 317 PM CDT MON SEP 16 2013
LATEST SFC ANALYSIS WAS INDICATING HIGH PRESSURE DOMINATING THE
WESTERN GRT LKS AND UPPER MS RVR VALLEY. SUBSIDENCE FROM THE HEART
OF THIS FEATURE AND UPPER LEVEL RIDGING HELPING ERODE STRATOCU
FIELDS IN THE CWA...BUT SOME CLOUD FIELDS HOLDING FIRM ACRS SOUTH
CENTRAL INTO SOUTHEASTERN IA. ALOFT...WATER VAPOR IMAGERY WAS
INDICATING LINGERING MONSOONAL MOISTURE FIELDS ACRS THE CENTRAL
PLAINS OVER TO THE OH RVR/TN VALLEY REGIONS...WHILE MOISTURE OFF
INGRID SURGES INLAND ACRS MEX/SOUTHERN TX. UPSTREAM WAVE NOTED
ACRS THE NORTHWEST PLAINS ON WESTERN FLANK OF UPPER RIDGE AXIS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 317 PM CDT MON SEP 16 2013
TONIGHT...WILL FOLLOW LATEST RAP LLVL MOISTURE/RH GUIDANCE WHICH
SUGGESTS A CONTINUED CLEARING OF THE STRATOCU EXCEPT MAYBE THE FAR
SOUTHWESTERN CWA THROUGH THIS EVENING. IT ALSO SUGGESTS LLVL FLOW
TO VEER TO THE EAST-SOUTHEAST OVERNIGHT AND POSSIBLY START ADVECTING
MORE HIGHER RH LEVELS/STRATOCU FROM SOUTHEAST IL/IND LATE TONIGHT
AFTER MIDNIGHT. FOR NOW WILL MAINTAIN MOSTLY CLR SKIES OVERNIGHT
FOR BULK OF THE EASTERN HALF OF THE CWA AND BANK ON COOL LOWS IN THE
40S WITH LOW/DRY AMBIENT SFC DPTS. BUT SOME BUST POTENTIAL ON THE LOW
SIDE IF THE CLOUDS DO ADVECT IN FROM THE EAST LATER TONIGHT ALONG
WITH HIGHER DPTS FROM THOSE SAME AREAS. WILL KEEP LOWS IN THE LOW TO
MID 50S IN THE SOUTHWEST THIRD WITH EXPECTED MID DECK/HIGHER CLOUD
INCREASE LATER TONIGHT FROM THE SOUTHWEST IN THOSE AREAS. ELEVATED
WARM AIR ADVECTION PROCESSES ASSOCIATED WITH RIDGE-RIDING WAVE
MENTIONED ABOVE PUSHING ACRS EASTERN NEB AND WESTERN IA TO TAP IN THE
LINGERING MONSOONAL MOISTURE AND PRODUCE SHOWERS OVERNIGHT...BUT
RIDGING AND DRY AIR IN PLACE TO MAKE FOR MOST OF THE CWA REMAINING
DRY THROUGH 12Z TUE. MUCH OF INITIAL LIFT FROM APPROACHING UPPER WAVE
TO GO INTO TOP-DOWN SATURATION PROCESSES WITH VIRGA TO LIGHT
SHOWERS/SPRINKLES ACRS THE SOUTHWEST THIRD TOWARD DAYBREAK.
TUESDAY...DESPITE SOME DECENT MODEL INDICATED ELEVATED THTA-E
ADVECTION AND CONVERGENT REGIONS PUSHING ACRS THE SOUTHWESTERN
THIRD TO HALF OF THE DVN CWA AS THE DAY PROGRESSES...THE BATTLE
WILL BE ON WITH LARGE DRY AIRMASS TO THE EAST. LIKE THE PREVIOUS
SHIFT MENTIONED...SHARP MOISTURE AND PRECIP GRADIENTS MAY DEVELOP
LOCALLY WITH SOME AREAS/IN THE FAR SOUTHWEST/ GETTING UP TO A
QUARTER INCH OF RAIN BY MID AFTERNOON...AND AREAS EAST OF THE MS RVR
ESPECIALLY EAST CENTRAL AND NORTHEAST REMAINING DRY THROUGH 00Z WED.
WILL SPREAD IN POPS GENERALLY FROM WEST-SOUTHWEST TO EAST IN
DECREASING FASHION TUE. BUT SOME AREAS PROBABLY WARRANT CATEGORICAL
POPS WEST OF THE MS RVR. EXPECT MAINLY SHOWERS IN DECLINING FASHION
AS THEY SPREAD EASTWARD AND ENCOUNTER THE DRY AIR...BUT PROGGED
MID LEVEL MUCAPES OF 200-500 J/KG IF CORRECT...SUPPORTS ISOLATED
EMBEDDED THUNDER IN THE SOUTHWESTERN HALF ON TUE. TEMPS WILL BE A
CHALLENGE TUE DEPENDING ON CLOUD COVER AND EVAPO-COOLING FROM
PRECIP. WILL GO WITH COOLER VALUES HELD DOWN IN THE 60S IN THE
WEST WITH EARLIER ARRIVAL OF CLOUDS AND PRECIP...WARMER IN THE LOW
70S EAST OF THE MS RVR. ..12..
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 317 PM CDT MON SEP 16 2013
ACTIVE WX WILL BE SEEN ACROSS THE MIDWEST FOR THE REMAINDER OF THE
WORK WEEK WITH SEVERAL CHANCES FOR RAIN.
RAIN THAT MOVES INTO THE AREA TUESDAY AFTERNOON WILL OVERSPREAD THE
AREA TUESDAY NIGHT/WED. AS THE OVERALL FORCING WEAKENS ON WEDNESDAY
THE AREAL COVERAGE OF PRECIPITATION WILL DECREASE WEDNESDAY
AFTERNOON.
WED NIGHT/THURSDAY THE NEXT ROUND OF FORCING MOVES THROUGH THE AREA
HELPING TO RE-DEVELOP NEW CONVECTION. A RESPECTABLE LLJ DEVELOPS WED
NIGHT WHICH SHOULD RESULT IN CONSIDERABLE NOCTURNAL CONVECTION AFTER
MIDNIGHT AND INTO THURSDAY MORNING.
THE APPROACHING COLD FRONT ON THURSDAY IS EXPECTED TO HELP MAINTAIN
CONVECTION DURING THE AFTERNOON. THE AMOUNT OF CLOUD COVER MAY HOLD
DOWN TEMPERATURES SOMEWHAT BUT THEY SHOULD STILL BE CLOSE TO NORMAL.
THURSDAY NIGHT ON...
THE MODEL CONSENSUS HAS HIGH CHC/LIKELY POPS FOR THURS NIGHT AS THE
NEXT FRONT MOVES THROUGH THE AREA. THE FRONT WILL CLEAR THE AREA ON
FRIDAY SO ONLY SCHC/LOW CHC POPS ARE GIVEN BY THE MODEL CONSENSUS
FOR THE EASTERN HALF OF THE CWFA.
COOL CANADIAN HIGH BUILDS INTO THE GREAT LAKES FOR FRIDAY NIGHT
THROUGH SUNDAY NIGHT. THE MODEL CONSENSUS GIVES DRY CONDITIONS WITH
TEMPERATURES AVERAGING BELOW NORMAL.
SOUTHERLY FLOW DEVELOPING ON MONDAY WILL ALLOW TEMPERATURES TO AGAIN
WARM. THE MODEL CONSENSUS HAS DRY CONDITIONS FOR MONDAY WITH CHC
POPS FOR MONDAY NIGHT. ..08..
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1130 PM CDT MON SEP 16 2013
VFR CONDS THROUGH MOST OF THIS TAF CYCLE. WILL SPREAD LIGHT RAIN
AND SPRINKLES TO KCID/KMLI/KBRL TUESDAY AFTERNOON BUT VSBYS SHOULD
REMAIN P6SM. EAST WINDS 5 TO 10 KNOTS TONIGHT THEN SOUTHEAST
AROUND 10 KNOTS TUESDAY AND TUESDAY EVENING. SHOWERS AND SCATTERED
THUNDERSTORMS WILL BEGIN TO INCREASE TUESDAY EVENING AS ELEVATED
INSTABILITY INCREASES WITH THE RETURN OF DEEPER MOISTURE. CIGS
SHOULD ALSO LOWER TO MVFR CATEGORY TUESDAY EVENING...ESPECIALLY
AT KCID/KBRL.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...HAASE
SYNOPSIS...12
SHORT TERM...12
LONG TERM...08
AVIATION...HAASE
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1142 PM MDT MON SEP 16 2013
.UPDATE...
ISSUED AT 637 PM MDT MON SEP 16 2013
JUST COMPLETED AN EXTENSIVE UPDATE. MODELS PLAYING CATCHUP. SINCE
IT DID NOT CLEAR OFF...TEMPERATURES ARE STARTING OUT MUCH COOLER
THAN WHAT THE MODELS THINK. FOG HAS ALREADY DEVELOPED AND EXPECT
IT TO CONTINUE AS LOW LEVEL WIND FIELD WILL CONTINUE TO ADVECT IN
HIGHER DEWPOINTS. SO THROUGH TOMORROW MORNING HAVE INTRODUCED
WIDESPREAD FOG AND DRIZZLE. THE RUC IS CATCHING THIS THE BEST
RIGHT NOW WITH THE NAM/ECMWF NOT TOO FAR BEHIND.
CONSEQUENTLY ADJUSTED THE CLOUD COVER AND THE WIND FIELD...WHICH
THE RUC IS DOING THE BEST ON...AS WELL. ALSO CURRENT TEMPERATURES
WERE NEAR OR BELOW THE FORECAST MINS SO LOWERED THOSE ACCORDINGLY.
THE OTHER MAIN CHANGE WAS THE PRECIPITATION FORECAST. RIGHT NOW NOTHING
GOING ON...SO REMOVED THUNDERSTORMS THROUGH MID EVENING...AS ANOTHER
SHORTWAVE TROUGH MOVES IN FROM THE WEST. AT THE SAME TIME A RATHER
STRONG 700 MB WARM AIR ADVECTION DEVELOPS AS A WEAK RIGHT REAR
QUADRANT OF 250 MB JET AFFECTS THE AREA AS WELL.
THESE ALL COME TOGETHER AND INCREASE IN STRENGTH AS THE NIGHT GOES
ON. THETA-E LAPSE RATES ARE VERY FAVORABLE FOR RESPONSE TO THE
LIFT. ELEVATED CAPE INCREASES AS ELEVATED CINH DECREASES. RIGHT
NOW THE BEST CHANCE FOR THUNDERSTORMS WILL BE AFTER 06Z AND IN THE
EASTERN HALF. WOULD NOT BE SURPRISED IF THUNDERSTORMS BECOME RATHER
STRONG CONSIDERING THE AMOUNT OF CAPE AND THE VERY FAVORABLE LAPSE
RATES.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH TUESDAY)
ISSUED AT 1148 AM MDT MON SEP 16 2013
A COOL HIGH PRESSURE AREA REMAINS IN PLACE OVER THE FORECAST AREA
TODAY AS A FEW LIGHT TO MODERATE SHOWERS MOVE NORTHEASTWARD ACROSS
THE EASTERN SECTIONS OF THE FORECAST AREA. THESE SHOWERS ARE A
RESULT OF A COUPLE OF SHORT WAVE TROUGHS IN THE UPPER FLOW MOVING
EAST OF THE ROCKIES AND ACROSS THE CENTRAL HIGH PLAINS REGION THIS
AFTERNOON AND EVENING. EXPECT A FEW MORE SHOWERS TO DEVELOP AS A
SECOND WEAKER SHORT WAVE TROUGH FOLLOWS IN ITS PATH. BEHIND THOSE
WAVES A WEAK RIDGE AND MORE WESTERLY FLOW MOVES EAST OF THE
ROCKIES WITH AN AREA OF SUBSIDENCE ACROSS THE FORECAST AREA ON
TUESDAY AND A LEE TROUGH THAT DEEPENS ALONG THE FRONT RANGE OF
WYOMING AND COLORADO. AS THIS TROUGH DEEPENS...THE HIGH PRESSURE
AREA MOVES EAST AND THE MOIST RETURN FLOW BEGINS TO MOVE OUT OF
THE REGION TO BE REPLACED BY A DRYER SOUTH TO SOUTHWEST NEAR
SURFACE FLOW. LOW CLOUDS AND FOG THAT ARE EXPECTED TO DEVELOP
IN THE SATURATED AIR MASS ACROSS THE AREA OVERNIGHT ARE EXPECTED TO
DIMINISH BY LATE TUESDAY AFTERNOON AND EVENING WITH A RETURN OF
HIGH TEMPERATURES IN THE 80S.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 219 PM MDT MON SEP 16 2013
A SHORTWAVE RIDGE WILL BE OVER THE PLAINS TUESDAY NIGHT FOLLOWED BY
WESTERLY FLOW THROUGH THURSDAY AS A TROUGH MOVES ACROSS THE NORTHERN
PLAINS. A SURFACE TROUGH WILL EXTEND SOUTH INTO EASTERN COLORADO
TUESDAY NIGHT/WEDNESDAY. THIS TROUGH WILL MOVE SOUTHEAST INTO
NORTHWEST KANSAS WEDNESDAY NIGHT. HIGH PRESSURE WILL MOVE INTO
NORTHWEST KANSAS THURSDAY.
CONDITIONS WILL REMAIN DRY TUESDAY NIGHT AND WEDNESDAY DUE TO
SUBSIDENCE OVER THE AREA. SOME DYNAMICS MOVE INTO THE AREA WEDNESDAY
NIGHT BUT MOISTURE IS NOT IMPRESSIVE SO WILL CONTINUE SLIGHT CHANCE
POPS FOR THUNDERSTORMS. DYNAMICS STILL REMAIN OVER THE FA EAST OF
THE COLORADO BORDER THURSDAY MORNING AND SHIFT EAST SOME THURSDAY
AFTERNOON BEFORE MOVING OUT OF THE AREA. ONCE AGAIN, H8-7 LAYER
MEAN RH IS LACKING SO WILL CONTINUE SLIGHT CHANCE POPS.
850MB TEMPERATURES SUPPORT MAX TEMPERATURES REACHING THE UPPER
80S/LOWER 90S WEDNESDAY. MAX TEMPERATURES SHOULD COOL TO THE 70S
THURSDAY BEHIND THE TROUGH. MIN TEMPERATURES TUESDAY NIGHT WILL BE
IN THE UPPER 50S/LOWER 60S COOLING TO THE MID 50S TO LOWER 60S
WEDNESDAY NIGHT.
IN THE EXTENDED...(THURSDAY NIGHT THROUGH MONDAY)...THIS PART OF THE
FORECAST WILL BE DRY THROUGH SATURDAY NIGHT WITH A RIDGE AND
SUBSIDENCE OVER THE REGION. THE RIDGE SHIFTS EAST SUNDAY ALLOWING A
TROUGH TO MOVE EAST INTO THE AREA. SLIGHT CHANCE TO CHANCE POPS ARE
SUPPORTED WITH NIL POPS FOR MONDAY
MAX TEMPERATURES WILL WARM UP INTO THE 80S UNDERNEATH THE INFLUENCE
OF THE RIDGE AND THEN COOL TO THE MID AND UPPER 70S MONDAY BEHIND
THE EXITING SHORTWAVE. MIN TEMPERATURES WILL RESIDE IN THE LOWER TO
MID 50S THURSDAY AND FRIDAY NIGHTS MODERATING TO THE MID/UPPER 50S
SATURDAY/SUNDAY NIGHTS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1140 PM MDT MON SEP 16 2013
IFR TO LIFR CONDITIONS ARE EXPECTED AT BOTH SITES THROUGH THE
MORNING HOURS. AT KMCK...THERE IS ENOUGH OF A CHANCE TO HAVE A
THUNDERSTORM AFFECT THE SITE THAT DID INCLUDE A VCTS MENTION FROM
09Z TO 12Z. BY LATE MORNING TO EARLY AFTERNOON CONDITIONS WILL
IMPROVE FROM MVFR TO VFR.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...LOCKHART
LONG TERM...FS
AVIATION...BULLER
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1030 PM EDT WED SEP 18 2013
.UPDATE...
ISSUED AT 1030 PM EDT WED SEP 18 2013
FRESHENED UP THE SKY COVER AND HOURLY TEMPERATURES AND DEW POINTS TO
ACCOUNT FOR THE LATEST TRENDS. SOME PARTIAL CLEARING WILL WORK IN
FROM THE WEST...HOWEVER BELIEVE THAT LOW CLOUDS WILL FILL BACK IN
DURING THE OVERNIGHT WITH HIGH MOISTURE IN THE 1000-850 MB LAYER
LINGERING. LEFT THE POPS AS IS...ALTHOUGH THE LATEST HRRR HAS BACKED
OFF ON THE UPTICK IN CONVECTION TOWARDS DAWN FOR THE NORTHEASTERN
PORTION OF THE AREA.
UPDATE ISSUED AT 807 PM EDT WED SEP 18 2013
A FEW SHOWERS WILL WIND DOWN ACROSS NORTHEASTERN KENTUCKY IN THE NEXT
HOUR. THE LATEST SHORT RANGE MODELS SHOW A LULL IN THE ACTIVITY
THROUGH THE OVERNIGHT...BEFORE AN UPTICK OCCURS TOWARDS DAWN IN THE
NORTHEASTERN HALF OF THE AREA...AS A WEAK SHORT WAVE TROUGH MOVES
SOUTHEAST ACROSS OHIO VALLEY. HAVE BUMPED UP THE POPS A BIT
CONSIDERING THE DECENT MODEL AGREEMENT. ALSO ADDED SOME PATCHY FOG
AND MADE THE VALLEY TEMPERATURES A BIT MORE UNIFORM WITH ALL OF THE
CLOUD COVER AND STEADY DEW POINTS IN THE LOW 60S.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 307 PM EDT WED SEP 18 2013
THE MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE MAJOR UPPER AIR
FEATURES...HOWEVER THERE IS QUITE A BIT OF DIFFERENCE IN HOW THEY
HANDLE THE PRECIPITATION FORECASTS OVER THE NEXT 36 HOURS. A WARM
FRONT HAS MOVED TO THE NORTHEAST OF THE AREA AND EASTERN KENTUCKY IS
NOW IN THE WARM SECTOR WITH A SURFACE HIGH OFF THE EAST COAST AND A
SURFACE RIDGE EXTENDING ACROSS EASTERN KENTUCKY. A COLD FRONT IS OVER
THE HEARTLAND AND WILL BE APPROACHING THE AREA...HOWEVER WILL NOT
MOVE INTO EASTERN KENTUCKY UNTIL SATURDAY. THIS ALLOWS FOR THE GULF
TO BE OPENED UP AND THERE WILL BE SOME FAIRLY WARM...MOIST AND
CONDITIONALLY UNSTABLE AIR OVER THE AREA. THE MODELS DIFFER AS TO
WHEN WEAK LITTLE PERTURBATIONS WILL BE ABLE TO KICK OFF ANY
CONVECTIVE ACTIVITY. FROM EXPERIENCE...EXPECT THAT THERE WILL BE AN
AFTERNOON AND EVENING MAXIMUM OF CONVECTIVE ACTIVITY...HOWEVER THERE
MAY BE SOME UNEXPECTED LITTLE POPUPS DURING THE OFF HOURS. THE MODEL
BLEND HANDLED THE TEMPERATURES VERY WELL AND JUST MADE SOME MINOR
TWEAKS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 307 PM EDT WED SEP 18 2013
ON FRIDAY A COLD FRONT EXTENDING FROM THE WESTERN GREAT LAKES INTO
THE MID MS VALLEY WILL BE MOVING EAST AS AN UPPER LEVEL SHORT WAVE
TROUGH PUSHES EAST THROUGH THE PLAINS. THE UPPER TROUGH AND SURFACE
COLD FRONT WILL MOVE EAST WITH RAIN CHANCES INCREASING ACROSS THE
AREA AS WE HEAD INTO THE WEEKEND. MOST RECENT RUNS OF THE VARIOUS
OPERATIONAL MODELS ARE POINTING TOWARDS SLOW FRONTAL MOVEMENT WITH
THE FRONT MOVING ACROSS THE AREA ON SATURDAY...AND LIKELY STALLING
OUT. THE LATEST WPC GUIDANCE IS ALSO FAVORING THIS IDEA WITH THE
FRONT APPROACHING THE FORECAST AREA AT 12Z SATURDAY. OF THE
OPERATIONAL MODELS THE 12Z NAM IS THE OUTLIER...AS IT PUSHES THE
UPPER TROUGH AND SURFACE FRONT THROUGH MUCH QUICKER...WITH THE FRONT
EAST OF KY BY 15Z SATURDAY. WILL LEAN AWAY FROM THE NAM FORECAST AS
ALL THE OTHER MODELS ARE MUCH SLOWER. THE 12Z GFS SHOWS THE SOUTHERN
PART OF THE UPPER TROF SLOWING DOWN WITH AN UPPER LOW CLOSING OFF IN
THE VICINITY OF EASTERN KY BY SUNDAY. THE 00Z ECMWF AND 12Z GEM ALSO
SUPPORT THE IDEA OF SLOW MOVEMENT WITH AN UPPER LOW FORMING OVER THE
UPPER SOUTH INTO THE TN VALLEY. OVERALL...MODELS AND WPC GUIDANCE
POINT TOWARDS WET CONDITIONS OVER THE WEEKEND. THE LATEST BLENDED
LOAD ALSO SUPPORTS THIS. EXACTLY HOW LONG THE SLOW MOVING UPPER LOW
AND ASSOCIATED SURFACE LOW LINGER NEARBY AND CONTINUE TO AFFECT
OUR WEATHER IS STILL UNCERTAIN. THE 00Z ECMWF POINTS TOWARDS RAIN
CHANCES LINGERING INTO THE MIDDLE OF NEXT WEEK...WHILE THE 12Z GFS
IS DRIER...WITH LESS OF A CHANCE OF RAIN AFTER MONDAY. WHILE THE
STANDARD BLENDED LOAD RESULTED IN A CHANCE OF RAIN IN THE SOUTHEAST
ON TUESDAY AND WEDNESDAY HAVE DECIDED TO FOLLOW THE CONSENSUS OF
NEIGHBORING WFOS AND WILL GO WITH A DRY FORECAST ON TUESDAY AND
WEDNESDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 807 PM EDT WED SEP 18 2013
EXPECT CEILINGS TO GRADUALLY LOWER TO IFR TO LIFR THROUGH
DAWN...WITH WORSE CONDITIONS EXPECTED ON THE RIDGETOPS. A FEW
SHOWERS WILL ALSO BE SEEN GENERALLY ALONG AND NORTHEAST OF A LINE
FROM IOB TO JKL TO BLK. CEILINGS WILL GRADUALLY IMPROVE THROUGH THE
MORNING HOURS...WITH MAINLY VFR EXPECTED AFTER 18Z. SOME SCATTERED
CONVECTION WILL ALSO THREATEN DURING THE AFTERNOON.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEOGERIAN
SHORT TERM...JJ
LONG TERM...SBH
AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION
NWS PADUCAH KY
643 PM CDT Wed Sep 18 2013
.UPDATE...
ISSUED AT 642 PM CDT WED SEP 18 2013
The aviation section has been updated for the 00Z TAF issuance.
&&
.SHORT TERM /Tonight through Friday night/...
ISSUED AT 230 PM CDT WED SEP 18 2013
The showers and isolated thunderstorms that occurred this morning
have all but dissipated by mid afternoon. Partial clearing will
continue to spread slowly east. The trend toward low and mid level
drying is indicated by RAP and nam model soundings. This drying
appears to be in response to a gradual rebuilding of the 500 mb
ridge that was flattened by a weak impulse this morning.
Through Thursday...the mid level ridge will continue to slowly build
over our region. This should continue to suppress most convection
over the Lower Ohio and Mid Mississippi Valleys. Will keep slight
chance pops during the peak heating hours from roughly 18z to 00z to
account for isolated diurnally driven storms.
A rather strong cold front will approach from the northwest on
Thursday night...reaching southern Illinois and southeast Missouri
on Friday. The front will continue moving southeast across western
Kentucky and southwest Indiana on Friday evening. The 09z sref
timing looks reasonable. A deepening upper trough will enhance lift
along the frontal zone...and deep layer moisture will be high for
this time of year /sref precip water values about 1.9 inches/. Looks
like the first widespread significant rainfall of the month will
occur. Storm total qpf should be at least one half inch...with some
1 inch amounts likely in heavier convection. Severe weather
potential will depend on how much sunshine and diurnal heating takes
place ahead of the front. Isolated severe convection is currently
forecast by SPC /see day 3 outlook/.
South to southwest low level flow will keep unseasonably warm and
humid conditions in place through Friday. The nam continues to have
problems with too much moisture in the model...as shown in its high
pops and abundant cloudiness. The warmer gfs mos highs look better
for Thursday.
.LONG TERM /Saturday through Wednesday/...
ISSUED AT 230 PM CDT WED SEP 18 2013
Main issue in the extended looks to be with how quickly an upper
level trof will move east out of the region over the weekend. Models
seem to be trending toward a less progressive solution in this
respect. Both the operational GFS and ECMWF suggest showers will
linger into Saturday along and south of the Ohio River, east of
the H50 trof axis. Will bump up precip chances on Sat into the 40
to 50 percent range over much of the Pennyrile region of western
KY.
Otherwise, the most noticeable change over the weekend will be
another transition to much cooler and less humid conditions. Highs
both Saturday and Sunday will likely stay down in the 70s, with lows
Sat night mostly in the 50 to 55 degree range.
As we head into next week, it now appears as though an Omega
Blocking pattern will become established along the MS River Valley.
This should keep things quite dry across our region, with sunny,
warm afternoons and cool nights. Temperatures will warm a touch each
day, and most locations will likely be back into the middle 80s by
Wednesday afternoon. Humidity levels should stay low though.
&&
.AVIATION...
ISSUED AT 642 PM CDT WED SEP 18 2013
Isolated convective activity early this evening should dissipate
quickly with sunset and not pose a threat to any of the terminals.
Looks like scattered mid clouds will stream across the area
through the entire period, thickest in the northeast.
All guidance indicates that a light south wind will persist
through the night. This should prevent any significant fog
formation, but will have to watch KEVV and KOWB closely due to the
rainfall they received earlier today. Certainly cannot rule out
MVFR visibilities at any location late tonight due to the amount
of low-level moisture across the region. Will leave it out now
based on the 5kt winds expected.
Some guidance tries to develop scattered convection Thursday
afternoon. Not sure if there will be any development, but it would
likely be too sparse in coverage to warrant any mention in the
TAFs at this time.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...DRS
SHORT TERM...MY
LONG TERM...GM
AVIATION...DRS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
800 PM EDT WED SEP 18 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 148 PM EDT WED SEP 18 2013
A WARM FRONT WILL PUSH NORTHWARD THROUGH LOWER MICHIGAN TONIGHT
LEADING TO SOME SHOWERS AND THUNDERSTORMS. SOUTHWEST WINDS WILL
INCREASE THURSDAY ALLOWING FOR AND UNSEASONABLY WARM DAY. MOISTURE
FROM THE GULF OF MEXICO WILL STREAM INTO THE AREA THURSDAY NIGHT
AND EARLY FRIDAY AHEAD OF A COLD FRONT. AS THIS FRONT PUSHES
THROUGH THE REGION FRIDAY...A PERIOD OF SHOWERS AND THUNDERSTORMS
CAN BE EXPECTED.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 148 PM EDT WED SEP 18 2013
THE MAIN CHALLENGE IN THE SHORT TERM DEALS WITH THE TIMING AND
STRENGTH OF THE CONVECTION. STORMS IN NW ILLINOIS ARE SHOWN TO
WEAKEN AS THEY HEAD TOWARD CHICAGO THIS AFTERNOON. HRRR SHOWS
CONVECTION REDEVELOPING OVER LAKE MI LATER TONIGHT AND MOVING INTO
THE HOLLAND TO MUSKEGON REGION. THIS MAKES SENSE WITH A
STRENGTHENING LOW LEVEL JET ACCOMPANYING THE WARM FRONT THAT
FEATURES ELEVATED INSTABILITY. NOT ALL MODELS HAVE THIS...BUT THE
HRRR TENDS TO HANDLE THE CONVECTION BETTER THAN MOST. WILL
DECREASE POPS INLAND TONIGHT...BUT CLOSER TO LAKE MI WILL KEEP THE
LIKELY VALUES GOING. SEVERE WEATHER IS NOT FORECASTED...BUT
PERHAPS A HEAVY RAIN THREAT MAY EXIST.
A LULL IN THE CONVECTION IS EXPECTED THU AS NO FOCUSING MECHANISM
IS SHOWN. IT WILL BE A WARM AND INCREASINGLY HUMID. IT DOES BECOME
RATHER UNSTABLE...SO WILL HOLD ONTO A LOW POP FOR STORMS.
I RAISED POPS FOR FRIDAY. WITH PWAT VALUES APPROACHING 2 INCHES
AND A FRONT PRESSING IN ALONG WITH LIFT...IT SHOULD BE RATHER WET
AT TIMES. MODELS HAVE TRENDED SOMEWHAT FASTER WITH THE FRONT...SO
WE MAY BE ABLE TO START DRYING THINGS OUT FROM THE WEST BEFORE THE
END OF THE DAY. WILL WAIT TO SEE IF THIS TREND PERSISTS BEFORE
CHANGING FRIDAYS FORECAST. I DID LOWER POPS FOR FRIDAY NIGHT
BECAUSE OF THIS. AS FOR SEVERE WEATHER...THE STRONGER DEEP LAYER
SHEAR IS SHOWN TO LAG BEHIND THE COLD FRONT...SO SOMEWHAT OF A
LIMITED RISK. STILL WITH BETTER INSTABILITY DEVELOPING AND
INCREASING WIND FIELDS ALONG WITH A LOW LEVEL JET MOVING IN AND
STRENGTHENING...A RISK STILL EXISTS. WILL NEED TO MONITOR TRENDS
CLOSELY IN THE COMING DAYS.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 243 PM EDT WED SEP 18 2013
AN UNEVENTFUL PERIOD IS EXCEPTED FOR THIS WEEKEND AND INTO THE
FIRST HALF OF NEXT WEEK. HIGH PRESSURE OVER THE UPPER MIDWEST ON
SATURDAY WILL SLOWLY MOVE OVER THE GREAT LAKES BY LATE IN THE
WEEKEND. THIS HIGH WILL BE STALLED OVER THE AREA AS A STORM SYSTEM
MOVES UP THE EAST COAST THROUGH THE FIRST HALF OF THE WORK WEEK.
SO FAIR WEATHER SHOULD PREVAIL.
LOWERED TEMPS A BIT FOR SATURDAY AND SUNDAY AS WE WILL BE UNDER A
THERMAL TROUGH . BOTH DAYS SHOULD SEE HIGHS STAYING IN THE 60S. WE
SHOULD SEE A WARM UP INTO THE WORK WEEK. HOWEVER LOW LEVEL FLOW
WILL BE FROM THE EAST OR SOUTHEAST...SO ANY MODERATION OF TEMPS
WILL BE GENTLE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 800 PM EDT WED SEP 18 2013
THE MAIN CHALLENGE FOR THE TAFS IS WHETHER OR NOT TO INCLUDE TSTMS
AND WHAT THE TIMING OF THEM MIGHT BE.
LATEST HRRR AND NSSL WRF GUIDANCE SUGGESTS A FEW STORMS DEVELOPING
AFTER MIDNIGHT TONIGHT ALONG THE LK MI SHORELINE THEN DRIFTING
SLOWLY TO THE EAST/SOUTHEAST LATE TONIGHT INTO THURSDAY MORNING.
WILL INCLUDE VCTS IN THE TAFS STARTING AROUND 05Z AT MKG WHERE THE
HIGHEST POTENTIAL EXISTS AND WHERE CONFIDENCE IS MEDIUM TO HIGH. WILL
HAVE THE STORMS IMPACTING/REACHING THE LAN/JXN AREAS BY 10Z... BUT
CONFIDENCE IS LOWER FARTHER EAST.
IF THERE ARE STORMS AROUND ON THURSDAY MORNING... A LULL SHOULD
DEVELOP BETWEEN THESE STORMS /ENDING BY 18Z/... AND THE NEXT
POTENTIAL ROUND ON THURSDAY EVENING... WHICH WILL PROBABLY BE
AFTER 00Z FRIDAY.
&&
.MARINE...
ISSUED AT 148 PM EDT WED SEP 18 2013
WINDS ARE FORECASTED TO BE STRONGER THU INTO THU NIGHT. MAY NEED
SMALL CRAFT AND BEACH HAZARDS TO COVER THIS. UNTIL THEN THE
SOUTHERLY FLOW WILL KEEP WAVES UP TO AROUND 2 TO 4
FEET...ESPECIALLY OFF OF LITTLE AND BIG SABLE POINTS.
&&
.HYDROLOGY...
ISSUED AT 148 PM EDT WED SEP 18 2013
LOCALIZED HEAVY RAIN WILL BE POSSIBLE WITH THE STORMS TONIGHT AS A
LOW LEVEL JET MOVES IN PWAT VALUES CLIMB TO OVER 1.5 INCHES.
CORFIDI VECTORS SUGGESTS A LOCALIZED HEAVY RAIN THREAT MAY EXIST.
CURRENTLY IT APPEARS THAT AREAS ALONG THE LAKESHORE STAND THE
HIGHEST CHANCE FOR THE STORMS. A MORE WIDESPREAD ROUND OF STORMS
IS FORECASTED FOR THU NIGHT INTO FRI. PWAT VALUES LIKELY TO CLIMB
ABOVE 1.75 INCHES WITH ANOTHER LOW LEVEL JET PUSHING THROUGH.
CORFIDI VECTORS ALSO SUGGEST A HEAVY RAIN THREAT. HOW MUCH RAIN
FALLS WILL LIKELY DEPEND ON HOW EFFICIENT THE RAIN BECOMES AND HOW
THE CONVECTION EVOLVES. SUSPECT LOCALLY MORE THAN 2 INCHES WILL
FALL BY FRI NIGHT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...JK
AVIATION...MEADE
HYDROLOGY...MJS
MARINE...MJS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
422 PM EDT TUE SEP 17 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 421 PM EDT TUE SEP 17 2013
17Z WV IMAGERY AND RUC ANALYSIS INDICATED A WELL-DEFINED SHORTWAVE
LIFTING NE THROUGH ERN IA. DPVA...7H FGEN AND 305K ISENTROPIC ASCENT
ASSOC WITH THE SHORTWAVE HAS SUPPORTED AN AREA OF SHOWERS OVER
NORTHEAST IA. VIS SATELLITE HAS SHOWN AN EXPANSION OF DIURNAL CU
FROM MNM-DELTA-ALGER COUNTIES EASTWARD IN AN AREA OF HIGHER
DEWPOINTS (UPPER 40 TO LOWER 50S) AIDED BY SOUTHERLY FLOW OFF LAKE
MI AND BAY OF GREEN BAY. RDGG ALOFT AND AT THE SFC HAS KEPT THE REST
OF THE FCST AREA GENERALLY CLOUD FREE THIS AFTERNOON.
TONIGHT...MDLS SUGGEST THAT AS THE IA SHRTWV GRADUALLY LIFTS TO THE
NORTHEAST...MOISTURE WILL INCREASE AND BRING SOME LIGHT WAA PCPN
INTO THE AREA AS 300K-310K ISENTROPIC ASCENT SPREADS FROM SE MN AND
WRN WI TOWARD UPPER MI. THE NAM/GFS ARE STILL A BIT MORE AGGRESSIVE
IN BRINGING SOME LIGHT PCPN INTO THE CWA COMPARED TO THE GEM/ECMWF.
GIVEN THE VERY DRY ANTECEDENT AIRMASS...THE NAM/GFS MAY BE TOO QUICK
SO USED MORE OF A MODEL BLEND FOR POPS WITH ONLY A 30 PCT CHC OF
LIGHT SHOWERS TOWARD 12Z NEAR THE WI BORDER WITH SLIGHT CHC ACROSS
MUCH OF THE REST OF THE WEST HALF.
WEDNESDAY...GIVEN PREDICTED TRACK OF ERN IA SHORTWAVE EXPECT BEST
FORCING FOR SHRA TO BE MAINLY CENTRAL COUNTIES IN THE MORNING AND
THEN TO SPREAD INTO THE EASTERN COUNTIES IN THE AFTERNOON. HAVE ONLY
SLIGHT CHC POPS FOR SHRA WEST AWAY FROM BETTER FORCING ASSOC WITH
SHORTWAVE. MODEL MLCAPES OTHER THAN NAM SHOW ONLY MARGINAL
INSTABILITY OF A FEW HUNDRED J/KG AT BEST OVER THE AREA SO WILL ONLY
INCLUDED SLIGHT CHC MENTION OF TS IN THE GRIDS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 421 PM EDT TUE SEP 17 2013
LITTLE CHANGES TO THE LARGE SCALE PATTERN FOR THE LONG TERM PERIOD
OVER THE LAST 24 HOURS. AREA WILL BE UNDER WEAK UPPER RIDGING TO
START THE PERIOD...WHICH WILL LEAD TO BROAD WARM AIR ADVECTION AND
THE POTENTIAL FOR SOME SHOWERS/THUNDERSTORMS WEDNESDAY NIGHT INTO
THURSDAY AS A WARM FRONT LIFTS ACROSS THE AREA. BEST CHANCES ON
WEDNESDAY NIGHT WILL BE EARLY ON WHEN THE STRONGEST WARM AIR
ADVECTION MOVES THROUGH AND BEFORE THE DEEPER MOISTURE STARTS TO
CUTOUT. THIS BROAD WAA WILL ALSO LEAD TO TEMPERATURES RISING TO
ABOVE NORMAL VALUES FOR WEDNESDAY NIGHT AND THURSDAY...WITH LOWS IN
THE UPPER 50S AND LOWER 60S AND HIGHS IN THE 70S TO LOWER 80S.
FINALLY FOR WEDNESDAY NIGHT...SINCE THE MODELS CONTINUE TO SHOW THE
POTENTIAL FOR LOW CLOUDS AND FOG...DID UP THE FOG TO AREAS FOR SOME
LOCATIONS IN FAVORED UPSLOPE HIGHER TERRAIN.
PRECIPITATION CHANCES WILL INCREASE HEADING INTO LATE THURSDAY
AFTERNOON AND THURSDAY NIGHT...AS THE UPPER TROUGH PUSHES NORTHEAST
THROUGH THE UPPER GREAT LAKES AND ONTARIO. AN ASSOCIATED LOW
PRESSURE SYSTEM WILL MOVE THROUGH NORTHWEST ONTARIO...BUT IT WILL
PUSH A COLD FRONT EAST ACROSS THE CWA THURSDAY NIGHT INTO FRIDAY
MORNING. ECMWF IS STILL SHOWING THE SLOWEST FRONTAL PASSAGE...WITH
THE PRECIPITATION LINGERING INTO EARLY FRIDAY AFTERNOON AS ANOTHER
WAVE RIDES UP THE FRONT. THERE CONTINUES TO BE SOME MINOR TIMING
DIFFERENCES IN THE COLD FRONT PASSAGE AND SHOWERS...BUT THE GENERAL
IDEA IS SIMILAR WITH MOST LOCATIONS LIKELY TO SEE 0.25-0.5IN OF
RAIN. AS FOR THUNDER...THERE ARE DECENT VARIATIONS IN THE
INSTABILITY...WITH SOME MODELS EVEN SHOWING UP TO 3000 J/KG OF ML
CAPE IF THERE IS ENOUGH CLEARING/HEATING IN THE AFTERNOON. 0-6KM AND
EFFECTIVE SHEAR VALUES STILL LOOK TO BE ON THE MARGINAL SIDE
(25-30KTS) ON THURSDAY AFTERNOON AND THEN INCREASE RIGHT ALONG THE
FRONTAL BOUNDARY. WOULD THINK THE BEST OPPORTUNITY FOR STRONGER
THUNDERSTORMS WOULD BE RIGHT ALONG THE FRONT AS IT MOVES INTO THE
WESTERN CWA LATE THURSDAY AFTERNOON INTO THE EVENING. AT THIS
POINT...THINK BRIEF HEAVY RAIN AND MARGINALLY SEVERE HAIL WOULD BE
THE BIGGEST THREATS IF THE UPDRAFTS CAN BE SUSTAINED.
DRIER AND COOLER AIR WILL MOVE IN RIGHT BEHIND THE FRONT AND SHOULD
LEAD TO A PERIOD OF DRY WEATHER AND EVEN SOME CLEARING FOR A FEW
HOURS. BUT MUCH COLDER AIR...WILL START TO SURGE IN WITH MORE
LOW LEVEL MOISTURE LATER FRIDAY AFTERNOON AND CONTINUE INTO THE
FIRST PART OF SATURDAY. WITH THE FLOW BEING MORE
WEST-NORTHWEST...EXPECT THE MOST CLOUDS TO BE OVER THE NORTH HALF
OF THE CWA AND WITH THE COLDER AIR THERE...EVEN SOME LAKE ENHANCED
CLOUDS (DELTA-T VALUES BETWEEN 10-14) IN THOSE WIND FAVORED AREAS.
WITH THE LATEST TRENDS OF CLOUD DEPTHS BEING 3-4KFT...SHOULD BE
ENOUGH FOR ISOLATED/SCATTERED SHOWERS AND MAY NEED TO ADJUST POPS A
LITTLE HIGHER OVER THE COMING SHIFTS.
THE UPPER TROUGH WILL LIFT NORTHEAST ON SATURDAY NIGHT AND ALLOW
UPPER RIDGING AND HIGH PRESSURE TO BUILD INTO THE AREA FOR SUNDAY.
THUS...EXPECT A DRY SECOND HALF OF THE WEEKEND...ALTHOUGH
TEMPERATURES WON/T WARM UP TOO SIGNIFICANTLY (WITH HIGHS AROUND 60).
ALSO...SATURDAY NIGHT COULD SEE SOME FROST OVER THE INTERIOR WEST
WHERE SKIES BEGIN TO CLEAR AND WINDS LET UP DUE TO THE APPROACHING
HIGH.
THIS HIGH WILL QUICKLY SHIFT EAST-NORTHEAST INTO QUEBEC ON
MONDAY...AS THE AREA IS UNDER THE UPPER RIDGE AXIS. STILL EXPECT
MONDAY TO BE DRY AND MUCH WARMER (HIGHS IN THE MID-UPPER 60S)...BUT
THE NEXT UPPER TROUGH IS LURKING TO THE WEST. THIS UPPER TROUGH
LOOKS TO GIVE A GLANCING BLOW TO THE CWA ON MONDAY NIGHT INTO
TUESDAY AND WILL HIGHLIGHT THE BEST POPS OVER THE NORTHWESTERN HALF
OF THE CWA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 201 PM EDT TUE SEP 17 2013
WITH DRY HIGH PRES DOMINATING...VFR CONDITIONS WILL BE THE RULE FOR
ALL TAF SITES THROUGH THIS EVENING. A STRENGTHENING SOUTHERLY PRES
GRAD JUST ABV DEVELOPING RADIATION INVERSION WILL RESULT IN LLWS
TONIGHT AT TAF SITES. LATE TONIGHT...INCREASING LOW LEVEL MOISTURE
MOVING NORTHWARD FROM WI AHEAD OF AN ADVANCING SYSTEM OVER THE
CENTRAL PLAINS IS EXPECTED TO BRING MVFR CIGS INTO THE TAF SITES LATE
TONIGHT INTO MIDDAY WEDNESDAY. KSAW WILL HAVE THE BEST CHC OF
PREVAILING SHRA CLOSER TO THE BEST FORCING FROM THE SYSTEM WHILE KIWD
AND KCMX SHOULD ONLY SEE VCSH
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 421 PM EDT TUE SEP 17 2013
BETWEEN HIGH TO THE EAST AND LOW PRES OVER THE PLAINS...SRLY WINDS
WILL REMAIN UP TO 20 KNOTS INTO WED. WINDS SHOULD THEN REMAIN BELOW
20 KNOTS UNTIL LATE THU NIGHT AND FRI WHEN A COLD FRONT MOVES
THROUGH THE REGION AND BRINGS W TO NW WINDS UP TO 30 KNOTS FRI INTO
SAT. WINDS WILL DECREASE BLO 20 KT BY SUNDAY AS HIGH PRESSURE BUILDS
IN FM THE WEST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
215 PM EDT TUE SEP 17 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 508 AM EDT TUE SEP 17 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE FROM
IL/WI INTO NW ONTARIO. AT THE SFC...A RIDGE WAS LOCATED OVER THE ERN
GREAT LAKES RESULTING IN SRLY THROUGH THE UPPER MS VALLEY INTO THE
WRN CWA. THE COMBINATION OF WAA AND A WEAK UPSTREAM SHORTWAVE TROUGH
OVER IA SUPPORTED AN AREA OF LIGHT SHOWERS FROM ERN NEB INTO NW IA.
OTHERWISE...IR LOOP INDICATED CLEAR SKIES OVER THE NRN GREAT LAKES.
TODAY...HIGH PRES AND THE LINGERING DRY AIRMASS WILL CONTINUE TO
DOMINATE THE WEATHER WITH MOSTLY SUNNY SKIES OVER UPPER MI. MIXING
TO AROUND 900-875 MB (AROUND 11C) WILL RESULT IN MAX READINGS IN THE
MID TO UPPER 60S.
TONIGHT...MDLS SUGGEST THAT AS THE IA SHRTWV GRADUALLY LIFTS TO THE
NORTHEAST...MOISTURE WILL INCREASE AND SOME LIGHT WAA PCPN WITH AREA
OF 300K-310K ISENTROPIC LIFT WILL SPREAD FROM SE MN AND WRN WI
TOWARD UPPER MI. THE NAM/GFS WERE A BIT MORE AGGRESSIVE IN BRINGING
SOME LIGHT PCPN INTO THE CWA COMPARED TO THE GEM/ECMWF. GIVEN THE
VERY DRY ANTECEDENT AIRMASS...THE FCST LEANS MORE TOWARD THE SLOWER
ONSET OF PCPN WITH ONLY A SLIGHT CHANCE OF LIGHT SHOWERS TOWARD 12Z
NEAR THE WI BORDER.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 447 AM EDT TUE SEP 17 2013
WED THROUGH MOST OF THU...A LOW PRESSURE SYSTEM CURRENTLY OFF THE
PACIFIC NW CONUS WILL DEEPEN WHILE MOVING FROM MT AT 12Z WED TO THE
CENTRAL SASKATCHEWAN/ONTARIO BORDER BY 00Z FRI. WILL DISCUSS PRECIP
ALONG THE COLD FRONT THAT MOVES IN LATE THU MOMENTARILY...BUT BEFORE
THAT MOVES IN EXPECT JUST SOME MINOR PRECIP. BEST CHANCE FOR PRECIP
LOOKS TO BE WITH BROAD WAA AHEAD OF THE SYSTEM...SO SOME LIGHT
PRECIP IS DIFFICULT TO FORECAST. HOWEVER...AGREE WITH PREVIOUS SHIFT
THAT SLIGHT CHANCE TO LOW CHANCE POPS SEEM WARRANTED PRIOR TO COLD
FROPA. HIGHS WED LOOK TO BE AROUND 70 WITH 850MB TEMPS OF 10-14C.
THU TEMPS LOOKS MORE CONDITIONAL AS LOW CLOUDS MAY INHIBIT MIXING OF
14-19C 850MB TEMPS...BUT COULD SEE HIGHS IN THE MID 70S IF ENOUGH
CLEARING OCCURS.
NOW FOR THE PROMISED DISCUSSION OF PRECIP ALONG THE COLD FRONT. THE
LOW WILL CONTINUE DEEPENING AS IT MOVES TO HUDSON BAY BY 00Z
SAT...THEN REMAINS NEARLY STATIONARY WHILE OCCLUDING THROUGH THE
REST OF SAT. WHILE DISCUSSING THE TRACK/TIMING OF THE SYSTEM...LET
IT BE SAID THAT MODELS ARE DOING MUCH BETTER THAN 24 HOURS
AGO...BOTH WITH RUN TO RUN CONTINUITY AND WITH MODEL TO MODEL
AGREEMENT. STILL THINK THERE WILL BE SHIFTS IN THE TRACK/TIMING BY
THE MODELS OVER THE NEXT FEW RUNS...BUT SHOULD AT LEAST BE GETTING A
BETTER IDEA OF WHAT THE SYSTEM WILL DO. THE COLD FRONT TIMING IS
ALSO SIMILAR BETWEEN MODEL RUNS...AT LEAST RELATIVELY SO FOR THIS
TYPE OF SYSTEM...WITH THE FRONT MOVING INTO THE FAR WRN CWA AROUND
00Z FRI...THEN TO THE CENTRAL CWA AROUND 12Z FRI AND TO THE ERN CWA
BY 18Z FRI. EXPECT A LINE OF SHOWERS AND THUNDERSTORMS TO MOVE
ACROSS THE CWA MAINLY THU NIGHT...AND AGREE WITH PREVIOUS SHIFT THAT
LIKELY POPS ARE JUSTIFIED. DRY SLOT MOVES IN BEHIND THE
FRONT...WHICH SHOULD BRING AN END TO SYNOPTIC PRECIP AS THE
MID/UPPER LEVELS DRY OUT. HOWEVER...WRAP AROUND MOISTURE WILL STILL
BE PRESENT IN THE LOW LEVELS AS THE UPPER TROUGH MOVES OVERHEAD FRI
INTO FRI NIGHT WITH 850MB TEMPS AS LOW AS 1C THROUGH 00Z FRI AND AS
LOW AS -2C FRI NIGHT. WLY LOW LEVEL WINDS MEANS THE W WIND LAKE
EFFECT/UPSLOPE BELTS WILL SEE THE BEST CHANCES FOR RAIN BEHIND THE
FRONT FRI AND FRI NIGHT.
MODELS DO START TO VARY MORE WITH HOW LONG TO LINGER THE UPPER
TROUGH OVER THE AREA SAT AND HOW QUICK TO BRING IN AN UPPER RIDGE
FROM THE W. THE GFS IS SLOWER WITH THE TROUGH AND HAS 850MB TEMPS
AROUND -2C AT 00Z SUN WHILE THE ECMWF HAS 850MB TEMPS OF 2-8C AT THE
SAME TIME. THEREFORE...HAVE LITTLE CONFIDENCE IN TEMPS FOR SAT. WITH
SUCH A SPREAD IN LOW LEVEL TEMPS...THERE IS ALSO A SPREAD IN
POSSIBILITIES FOR LAKE EFFECT RAIN...SO WILL CONTINUE TO HAVE SLIGHT
CHANCE IN THE FORECAST.
SUN SHOULD SEE A WARM UP AS THE UPPER RIDGE MOVES OVERHEAD...BUT
STILL NOT VERY CONFIDENT ON EXACT TEMPS FOR THE DAY GIVEN CONTINUED
MODEL SPREAD...BUT AT LEAST SHOULD BE WARMER AND DRIER THAN SAT.
MON SHOULD AGAIN SEE WARMING TEMPS AS SLY FLOW INCREASES AHEAD OF
THE NEXT LOW PRESSURE SYSTEM DEVELOPING OVER THE PLAINS. .
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 201 PM EDT TUE SEP 17 2013
WITH DRY HIGH PRES DOMINATING...VFR CONDITIONS WILL BE THE RULE FOR
ALL TAF SITES THROUGH THIS EVENING. A STRENGTHENING SOUTHERLY PRES
GRAD JUST ABV DEVELOPING RADIATION INVERSION WILL RESULT IN LLWS
TONIGHT AT TAF SITES. LATE TONIGHT...INCREASING LOW LEVEL MOISTURE
MOVING NORTHWARD FROM WI AHEAD OF AN ADVANCING SYSTEM OVER THE
CENTRAL PLAINS IS EXPECTED TO BRING MVFR CIGS INTO THE TAF SITES LATE
TONIGHT INTO MIDDAY WEDNESDAY. KSAW WILL HAVE THE BEST CHC OF
PREVAILING SHRA CLOSER TO THE BEST FORCING FROM THE SYSTEM WHILE KIWD
AND KCMX SHOULD ONLY SEE VCSH &&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 508 AM EDT TUE SEP 17 2013
AS THE HIGH SHIFTS TO THE EAST...SRLY WINDS UP TO 20 KNOTS ARE
EXPECTED FROM TODAY INTO WED. WINDS SHOULD THEN REMAIN BELOW 20
KNOTS UNTIL FRI WHEN A COLD FRONT MOVES THROUGH THE REGION AND
BRINGS W TO NW WINDS UP TO 30 KNOTS FRI INTO SAT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...VOSS
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
750 AM EDT TUE SEP 17 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 508 AM EDT TUE SEP 17 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE FROM
IL/WI INTO NW ONTARIO. AT THE SFC...A RIDGE WAS LOCATED OVER THE ERN
GREAT LAKES RESULTING IN SRLY THROUGH THE UPPER MS VALLEY INTO THE
WRN CWA. THE COMBINATION OF WAA AND A WEAK UPSTREAM SHORTWAVE TROUGH
OVER IA SUPPORTED AN AREA OF LIGHT SHOWERS FROM ERN NEB INTO NW IA.
OTHERWISE...IR LOOP INDICATED CLEAR SKIES OVER THE NRN GREAT LAKES.
TODAY...HIGH PRES AND THE LINGERING DRY AIRMASS WILL CONTINUE TO
DOMINATE THE WEATHER WITH MOSTLY SUNNY SKIES OVER UPPER MI. MIXING
TO AROUND 900-875 MB (AROUND 11C) WILL RESULT IN MAX READINGS IN THE
MID TO UPPER 60S.
TONIGHT...MDLS SUGGEST THAT AS THE IA SHRTWV GRADUALLY LIFTS TO THE
NORTHEAST...MOISTURE WILL INCREASE AND SOME LIGHT WAA PCPN WITH AREA
OF 300K-310K ISENTROPIC LIFT WILL SPREAD FROM SE MN AND WRN WI
TOWARD UPPER MI. THE NAM/GFS WERE A BIT MORE AGGRESSIVE IN BRINGING
SOME LIGHT PCPN INTO THE CWA COMPARED TO THE GEM/ECMWF. GIVEN THE
VERY DRY ANTECEDENT AIRMASS...THE FCST LEANS MORE TOWARD THE SLOWER
ONSET OF PCPN WITH ONLY A SLIGHT CHANCE OF LIGHT SHOWERS TOWARD 12Z
NEAR THE WI BORDER.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 447 AM EDT TUE SEP 17 2013
WED THROUGH MOST OF THU...A LOW PRESSURE SYSTEM CURRENTLY OFF THE
PACIFIC NW CONUS WILL DEEPEN WHILE MOVING FROM MT AT 12Z WED TO THE
CENTRAL SASKATCHEWAN/ONTARIO BORDER BY 00Z FRI. WILL DISCUSS PRECIP
ALONG THE COLD FRONT THAT MOVES IN LATE THU MOMENTARILY...BUT BEFORE
THAT MOVES IN EXPECT JUST SOME MINOR PRECIP. BEST CHANCE FOR PRECIP
LOOKS TO BE WITH BROAD WAA AHEAD OF THE SYSTEM...SO SOME LIGHT
PRECIP IS DIFFICULT TO FORECAST. HOWEVER...AGREE WITH PREVIOUS SHIFT
THAT SLIGHT CHANCE TO LOW CHANCE POPS SEEM WARRANTED PRIOR TO COLD
FROPA. HIGHS WED LOOK TO BE AROUND 70 WITH 850MB TEMPS OF 10-14C.
THU TEMPS LOOKS MORE CONDITIONAL AS LOW CLOUDS MAY INHIBIT MIXING OF
14-19C 850MB TEMPS...BUT COULD SEE HIGHS IN THE MID 70S IF ENOUGH
CLEARING OCCURS.
NOW FOR THE PROMISED DISCUSSION OF PRECIP ALONG THE COLD FRONT. THE
LOW WILL CONTINUE DEEPENING AS IT MOVES TO HUDSON BAY BY 00Z
SAT...THEN REMAINS NEARLY STATIONARY WHILE OCCLUDING THROUGH THE
REST OF SAT. WHILE DISCUSSING THE TRACK/TIMING OF THE SYSTEM...LET
IT BE SAID THAT MODELS ARE DOING MUCH BETTER THAN 24 HOURS
AGO...BOTH WITH RUN TO RUN CONTINUITY AND WITH MODEL TO MODEL
AGREEMENT. STILL THINK THERE WILL BE SHIFTS IN THE TRACK/TIMING BY
THE MODELS OVER THE NEXT FEW RUNS...BUT SHOULD AT LEAST BE GETTING A
BETTER IDEA OF WHAT THE SYSTEM WILL DO. THE COLD FRONT TIMING IS
ALSO SIMILAR BETWEEN MODEL RUNS...AT LEAST RELATIVELY SO FOR THIS
TYPE OF SYSTEM...WITH THE FRONT MOVING INTO THE FAR WRN CWA AROUND
00Z FRI...THEN TO THE CENTRAL CWA AROUND 12Z FRI AND TO THE ERN CWA
BY 18Z FRI. EXPECT A LINE OF SHOWERS AND THUNDERSTORMS TO MOVE
ACROSS THE CWA MAINLY THU NIGHT...AND AGREE WITH PREVIOUS SHIFT THAT
LIKELY POPS ARE JUSTIFIED. DRY SLOT MOVES IN BEHIND THE
FRONT...WHICH SHOULD BRING AN END TO SYNOPTIC PRECIP AS THE
MID/UPPER LEVELS DRY OUT. HOWEVER...WRAP AROUND MOISTURE WILL STILL
BE PRESENT IN THE LOW LEVELS AS THE UPPER TROUGH MOVES OVERHEAD FRI
INTO FRI NIGHT WITH 850MB TEMPS AS LOW AS 1C THROUGH 00Z FRI AND AS
LOW AS -2C FRI NIGHT. WLY LOW LEVEL WINDS MEANS THE W WIND LAKE
EFFECT/UPSLOPE BELTS WILL SEE THE BEST CHANCES FOR RAIN BEHIND THE
FRONT FRI AND FRI NIGHT.
MODELS DO START TO VARY MORE WITH HOW LONG TO LINGER THE UPPER
TROUGH OVER THE AREA SAT AND HOW QUICK TO BRING IN AN UPPER RIDGE
FROM THE W. THE GFS IS SLOWER WITH THE TROUGH AND HAS 850MB TEMPS
AROUND -2C AT 00Z SUN WHILE THE ECMWF HAS 850MB TEMPS OF 2-8C AT THE
SAME TIME. THEREFORE...HAVE LITTLE CONFIDENCE IN TEMPS FOR SAT. WITH
SUCH A SPREAD IN LOW LEVEL TEMPS...THERE IS ALSO A SPREAD IN
POSSIBILITIES FOR LAKE EFFECT RAIN...SO WILL CONTINUE TO HAVE SLIGHT
CHANCE IN THE FORECAST.
SUN SHOULD SEE A WARM UP AS THE UPPER RIDGE MOVES OVERHEAD...BUT
STILL NOT VERY CONFIDENT ON EXACT TEMPS FOR THE DAY GIVEN CONTINUED
MODEL SPREAD...BUT AT LEAST SHOULD BE WARMER AND DRIER THAN SAT.
MON SHOULD AGAIN SEE WARMING TEMPS AS SLY FLOW INCREASES AHEAD OF
THE NEXT LOW PRESSURE SYSTEM DEVELOPING OVER THE PLAINS. .
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 750 AM EDT TUE SEP 17 2013
WITH DRY HIGH PRES DOMINATING...VFR CONDITIONS WILL BE THE RULE FOR
MOST OF THE FCST PERIOD AT ALL 3 TAF SITES. AS THE HIGH DRIFTS
FARTHER E AND A STRONGER PRES GRADIENT TAKES SHAPE OVER THE NRN
GREAT LAKES...EXPECT A GUSTY S WIND TO DEVELOP BY THIS AFTERNOON
IN THE PRESENCE OF DAYTIME HEATING/MIXING. LLWS WILL RESULT TONIGHT WITH
NOCTURNAL COOLING CAUSING A RADIATION INVERSION AND DECOUPLING OF A
LIGHTER SFC FLOW FM THE STRONGER WINDS ABOVE THE INVERSION. LATE
TONIGHT...INCREASING LOW LEVEL MOISTURE MOVING NORTHWARD FROM WI IS
EXPECTED TO BRING MVFR CIGS INTO IWD/SAW TOWARD THE END OF THE FCST
PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 508 AM EDT TUE SEP 17 2013
AS THE HIGH SHIFTS TO THE EAST...SRLY WINDS UP TO 20 KNOTS ARE
EXPECTED FROM TODAY INTO WED. WINDS SHOULD THEN REMAIN BELOW 20
KNOTS UNTIL FRI WHEN A COLD FRONT MOVES THROUGH THE REGION AND
BRINGS W TO NW WINDS UP TO 30 KNOTS FRI INTO SAT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FROST ADVISORY UNTIL 9 AM EDT /8 AM CDT/ THIS MORNING FOR MIZ002-
004>007-009>014-084-085.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
509 AM EDT TUE SEP 17 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 508 AM EDT TUE SEP 17 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE FROM
IL/WI INTO NW ONTARIO. AT THE SFC...A RIDGE WAS LOCATED OVER THE ERN
GREAT LAKES RESULTING IN SRLY THROUGH THE UPPER MS VALLEY INTO THE
WRN CWA. THE COMBINATION OF WAA AND A WEAK UPSTREAM SHORTWAVE TROUGH
OVER IA SUPPORTED AN AREA OF LIGHT SHOWERS FROM ERN NEB INTO NW IA.
OTHERWISE...IR LOOP INDICATED CLEAR SKIES OVER THE NRN GREAT LAKES.
TODAY...HIGH PRES AND THE LINGERING DRY AIRMASS WILL CONTINUE TO
DOMINATE THE WEATHER WITH MOSTLY SUNNY SKIES OVER UPPER MI. MIXING
TO AROUND 900-875 MB (AROUND 11C) WILL RESULT IN MAX READINGS IN THE
MID TO UPPER 60S.
TONIGHT...MDLS SUGGEST THAT AS THE IA SHRTWV GRADUALLY LIFTS TO THE
NORTHEAST...MOISTURE WILL INCREASE AND SOME LIGHT WAA PCPN WITH AREA
OF 300K-310K ISENTROPIC LIFT WILL SPREAD FROM SE MN AND WRN WI
TOWARD UPPER MI. THE NAM/GFS WERE A BIT MORE AGGRESSIVE IN BRINGING
SOME LIGHT PCPN INTO THE CWA COMPARED TO THE GEM/ECMWF. GIVEN THE
VERY DRY ANTECEDENT AIRMASS...THE FCST LEANS MORE TOWARD THE SLOWER
ONSET OF PCPN WITH ONLY A SLIGHT CHANCE OF LIGHT SHOWERS TOWARD 12Z
NEAR THE WI BORDER.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 447 AM EDT TUE SEP 17 2013
WED THROUGH MOST OF THU...A LOW PRESSURE SYSTEM CURRENTLY OFF THE
PACIFIC NW CONUS WILL DEEPEN WHILE MOVING FROM MT AT 12Z WED TO THE
CENTRAL SASKATCHEWAN/ONTARIO BORDER BY 00Z FRI. WILL DISCUSS PRECIP
ALONG THE COLD FRONT THAT MOVES IN LATE THU MOMENTARILY...BUT BEFORE
THAT MOVES IN EXPECT JUST SOME MINOR PRECIP. BEST CHANCE FOR PRECIP
LOOKS TO BE WITH BROAD WAA AHEAD OF THE SYSTEM...SO SOME LIGHT
PRECIP IS DIFFICULT TO FORECAST. HOWEVER...AGREE WITH PREVIOUS SHIFT
THAT SLIGHT CHANCE TO LOW CHANCE POPS SEEM WARRANTED PRIOR TO COLD
FROPA. HIGHS WED LOOK TO BE AROUND 70 WITH 850MB TEMPS OF 10-14C.
THU TEMPS LOOKS MORE CONDITIONAL AS LOW CLOUDS MAY INHIBIT MIXING OF
14-19C 850MB TEMPS...BUT COULD SEE HIGHS IN THE MID 70S IF ENOUGH
CLEARING OCCURS.
NOW FOR THE PROMISED DISCUSSION OF PRECIP ALONG THE COLD FRONT. THE
LOW WILL CONTINUE DEEPENING AS IT MOVES TO HUDSON BAY BY 00Z
SAT...THEN REMAINS NEARLY STATIONARY WHILE OCCLUDING THROUGH THE
REST OF SAT. WHILE DISCUSSING THE TRACK/TIMING OF THE SYSTEM...LET
IT BE SAID THAT MODELS ARE DOING MUCH BETTER THAN 24 HOURS
AGO...BOTH WITH RUN TO RUN CONTINUITY AND WITH MODEL TO MODEL
AGREEMENT. STILL THINK THERE WILL BE SHIFTS IN THE TRACK/TIMING BY
THE MODELS OVER THE NEXT FEW RUNS...BUT SHOULD AT LEAST BE GETTING A
BETTER IDEA OF WHAT THE SYSTEM WILL DO. THE COLD FRONT TIMING IS
ALSO SIMILAR BETWEEN MODEL RUNS...AT LEAST RELATIVELY SO FOR THIS
TYPE OF SYSTEM...WITH THE FRONT MOVING INTO THE FAR WRN CWA AROUND
00Z FRI...THEN TO THE CENTRAL CWA AROUND 12Z FRI AND TO THE ERN CWA
BY 18Z FRI. EXPECT A LINE OF SHOWERS AND THUNDERSTORMS TO MOVE
ACROSS THE CWA MAINLY THU NIGHT...AND AGREE WITH PREVIOUS SHIFT THAT
LIKELY POPS ARE JUSTIFIED. DRY SLOT MOVES IN BEHIND THE
FRONT...WHICH SHOULD BRING AN END TO SYNOPTIC PRECIP AS THE
MID/UPPER LEVELS DRY OUT. HOWEVER...WRAP AROUND MOISTURE WILL STILL
BE PRESENT IN THE LOW LEVELS AS THE UPPER TROUGH MOVES OVERHEAD FRI
INTO FRI NIGHT WITH 850MB TEMPS AS LOW AS 1C THROUGH 00Z FRI AND AS
LOW AS -2C FRI NIGHT. WLY LOW LEVEL WINDS MEANS THE W WIND LAKE
EFFECT/UPSLOPE BELTS WILL SEE THE BEST CHANCES FOR RAIN BEHIND THE
FRONT FRI AND FRI NIGHT.
MODELS DO START TO VARY MORE WITH HOW LONG TO LINGER THE UPPER
TROUGH OVER THE AREA SAT AND HOW QUICK TO BRING IN AN UPPER RIDGE
FROM THE W. THE GFS IS SLOWER WITH THE TROUGH AND HAS 850MB TEMPS
AROUND -2C AT 00Z SUN WHILE THE ECMWF HAS 850MB TEMPS OF 2-8C AT THE
SAME TIME. THEREFORE...HAVE LITTLE CONFIDENCE IN TEMPS FOR SAT. WITH
SUCH A SPREAD IN LOW LEVEL TEMPS...THERE IS ALSO A SPREAD IN
POSSIBILITIES FOR LAKE EFFECT RAIN...SO WILL CONTINUE TO HAVE SLIGHT
CHANCE IN THE FORECAST.
SUN SHOULD SEE A WARM UP AS THE UPPER RIDGE MOVES OVERHEAD...BUT
STILL NOT VERY CONFIDENT ON EXACT TEMPS FOR THE DAY GIVEN CONTINUED
MODEL SPREAD...BUT AT LEAST SHOULD BE WARMER AND DRIER THAN SAT.
MON SHOULD AGAIN SEE WARMING TEMPS AS SLY FLOW INCREASES AHEAD OF
THE NEXT LOW PRESSURE SYSTEM DEVELOPING OVER THE PLAINS. .
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 129 AM EDT TUE SEP 17 2013
WITH DRY HI PRES DOMINATING...VFR CONDITIONS WL BE THE RULE THIS
FCST PERIOD AT ALL 3 TAF SITES. AS THE HI DRIFTS FARTHER E AND A
STRONGER PRES GRADIENT TAKES SHAPE OVER THE UPR LKS...EXPECT A GUSTY
S WIND TO DVLP BY THIS AFTN IN THE PRESENCE OF DAYTIME HEATING/
MIXING. LLWS WL RESULT TNGT WITH NOCTURNAL COOLING CAUSING A
RADIATION INVRN AND DECOUPLING OF A LIGHTER SFC FLOW FM THE STRONGER
WINDS ABV THE INVRN.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 508 AM EDT TUE SEP 17 2013
AS THE HIGH SHIFTS TO THE EAST...SRLY WINDS UP TO 20 KNOTS ARE
EXPECTED FROM TODAY INTO WED. WINDS SHOULD THEN REMAIN BELOW 20
KNOTS UNTIL FRI WHEN A COLD FRONT MOVES THROUGH THE REGION AND
BRINGS W TO NW WINDS UP TO 30 KNOTS FRI INTO SAT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FROST ADVISORY UNTIL 9 AM EDT /8 AM CDT/ THIS MORNING FOR MIZ002-
004>007-009>014-084-085.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
705 PM CDT WED SEP 18 2013
.UPDATE...
00Z AVIATION DISCUSSION ADDED BELOW.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 246 PM CDT WED SEP 18 2013
TODAY THRU TONIGHT...FAIRLY ACTIVE 24 HOURS AS A FRONTAL SYSTEM
MOVES ACROSS THE AREA. A WMFNT IS MAKING DECENT PROGRESS INTO SWRN
MN AS THAT PORTION OF THE STATE HAS CLEARED OUT...ALLOWING
TEMPERATURES TO SOAR INTO THE MID 80S. HOWEVER...WHERE THE LOW
STRATUS HAS HELD ON RATHER STRONG...WHICH INCLUDES MUCH OF
CENTRAL-EASTERN MN INTO WRN WI...TEMPS ARE STILL IN THE MID 60S TO
MID 70S. THE WRN FRINGES OF THE CLOUD SHIELD WILL CONTINUE TO ERODE
TO THE NE...BUT AS THE WMFNT MAKES FURTHER PROGRESS...THE MOIST AND
WARM LLVL FLOW WILL AGAIN TAKE HOLD UNDER THE INVERSION...BRINGING
LOW CLOUDS AGAIN TO THE AREA. THE HIGHER DEWPOINTS AND WARM AIR WILL
MAKE FOR A RELATIVELY MUGGY NIGHT WITH LESS WIND TO MIX THE BLYR SO
PATCHY FOG MAY AGAIN BE AN ISSUE. THAT SAID...SREF/RAP/NAM HINT
AGAINST THAT SUGGESTION AS DO CROSSOVER TEMPS SO HAVE NOT MADE
MENTION OF FOG ATTM. NOT FAR BEHIND THE WMFNT WILL BE ITS ASSOCIATED
CDFNT ...WITH THE MAIN SFC LOW PRES CENTER ROTATING NEWD FROM THE
CENTRAL DAKOTAS TWD NW MN AND SRN ONTARIO. THE SFC LOW WILL BE
PICKED UP BY A DIGGING LONGWAVE H5 TROF OVER THE NRN PLAINS...SO AS
THIS TROF DIGS...THE ADDED JETTING WILL GIVE FURTHER IMPETUS TO
SHWR/TSTM DEVELOPMENT IN ADVANCE OF THE CDFNT. PRECIP DEVELOPMENT
WILL COMMENCE IN EARNEST OVERNIGHT FROM S TO N...AND LOOKS TO
ENVELOP MUCH OF THE CWFA IN SCATTERED COVERAGE CLOSE TO DAYBREAK.
THE PRECIP WILL THEN SPREAD EWD THRU MUCH OF THE DAY TMRW...COMING
TO AN END FROM W TO E OVER MN DURG THE DAY TMRW. THERE IS POTENTIAL
FOR SOME DECENT PRECIP TOTALS AS PWATS REACH THE 1.75 INCH AREA...
BUT EVEN WITH SUCH MOIST AIR...INSTABILITY WILL BE STRONGLY LIMITED
BY THE DEEP WARM AIRMASS LEADING EXTENSIVE PERSISTENT CLOUD COVER
WHICH WILL PREVENT OPTIMAL SFC HEATING. MODELS INDICATE MLCAPES IN
THE 1500-2000 J/KG RANGE...POSSIBLY LEADING TO ELEVATED TSTMS...BUT
SO LONG AS THE LOW CLOUDS REMAIN IN PLACE...GETTING DEEP CONVECTION
WILL BE DIFFICULT. WILL MAINTAIN MENTION OF TSTMS FOR TMRW BUT
CONFIDENCE IS NOT GREAT ON PLACEMENT OR TIMING. REGARDING THE WARM
TEMPS...THE SLY FLOW THRU TNGT AND THE CLOUD BLANKET WILL ONLY ALLOW
LOWS TNGT TO DROP TO THE MID 60S TO LWR 70S. AHEAD OF THE CDFNT
TMRW... HIGHS WILL REACH THE MID 70S TO ARND 80 IN CENTRAL-SRN MN
AND THE LOW-MID 80S IN WRN WI.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 246 PM CDT WED SEP 18 2013
THE BASE OF THE TROUGH ASSOCIATED WITH THE AFOREMENTIONED SYSTEM IN
THE SHORT TERM DISCUSSION WILL TRANSVERSE MN BETWEEN 06-15Z THURSDAY
AND MOVE INTO WI BEFORE 18Z ON THURSDAY. THIS SYSTEM HAS TRENDED 3-6
HOURS FASTER OFF THE GFS AND ECMWF OVER THE PAST FEW RUNS...WHILE
THE NAM HAS REMAINED VERY STEADY. AS A RESULT...WE TRENDED THE
PRECIP OUT OF THE FORECAST AREA A TAD FASTER THAN THE MIDNIGHT
FORECAST...VERY LITTLE CHANGE OVERALL THOUGH. MUCH DRIER/COOLER POST
FRONTAL AIR MOVES IN ON FRIDAY WITH HIGHS IN THE 60S. FRIDAY MORNING
SHOULD RESEMBLE A TYPICALLY CRISP AND BREEZY FALL MORNING. NORTHWEST
FLOW LINGERS ON SATURDAY WITH TEMPS REMAINING COOL. RETURN FLOW SETS
IN TOWARD THE END OF THE WEEKEND...BUT AT LEAST AT THIS POINT...IT
LOOKS AS IF THE THERMAL RIDGE REMAINS WEST OF THE FORECAST AREA
THROUGH AT LEAST MID WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 705 PM CDT WED SEP 18 2013
WARM FRONT/CLEARING CONTINUING TO LIFT NE AT ABOUT 25 KTS AND
EXPECT ALL AIRPORTS TO BE VFR BY 00Z. ALL MODELS SHOW THESE LOW
CLOUDS STAYING NORTH OF THE FIELD THE REST OF THE NIGHT...SO
TRENDED 00Z TAFS TOWARD A MORE OPTIMISTIC DIRECTION. THE REALLY
HARD CALL STILL THIS PERIOD IS WHAT WILL HAPPEN WITH CONVECTION.
THERE ARE TWO AREAS TO WATCH...THE STORMS ASSOCIATED MORE WITH THE
UPPER WAVE IN NW SODAK...AND THE STRENGTHENING LLJ ACROSS IOWA.
THE LINE OF STORMS MORE IN THE ERN DAKOTAS IS SFC BASED...BUT
WILL REMAIN NEAR THE LOW/COLD FRONT THROUGH THE EVENING AND WILL
NOT COME TOWARD THE MPX AREA UNTIL THE UPPER WAVE CATCHES
UP...WHICH IS AFTER 03Z. FOLLOWED THE IDEA OF THE HRRR FOR TIMING
POTENTIAL SHRA INTO AXN/STC OVERNIGHT. AS FOR THE LLJ...THE HRRR
HAS BEEN VERY AGGRESSIVE WITH DEVELOPING ACTIVITY ON THE NOSE IT
ACROSS SE MN INTO WRN WI THIS EVENING...BUT TO THIS POINT...IT HAS
BEEN NOTHING MORE THAN A STABLE CU-FIELD ACROSS IOWA. WENT WITH VCSH
FOR MSP/RNH/EAU AFTER 9Z TO ACCOUNT FOR THIS. WITH THE HRRR BEING
ABOUT THE ONLY HI-RES GUIDANCE SHOWING THIS SCENARIO...CONFIDENCE
NOT HIGH ENOUGH TO GO WITH ANYTHING MORE. AS FOR THE COLD FRONT...
BASED ON THE HRRR/18Z NAM...IT LOOKS TO BE COMING THROUGH A
COUPLE OF HOURS EARLIER THAN WHAT 12Z GUIDANCE WAS SHOWING...SO
MOVED UP THUNDER MENTION ACCORDINGLY AT ERN TERMINALS. AS FOR ANY
MVFR CIGS...BEST CHANCE FOR SEEING THOSE RETURN TONIGHT BASED ON
THE RAP WILL BE IN WRN WI.
KMSP...LOW CONFIDENCE IN PRECIP AND CIG FORECAST THIS
PERIOD. RAW MODEL GUIDANCE FROM ALL MODELS WOULD SUGGEST MSP IS
DONE WITH ANY MVFR CIGS THE REST OF THE PERIOD...SO TRENDED THE
TAF THAT DIRECTION. LOTS OF UNCERTAINTY STILL WITH THE PRECIP
POTENTIAL...BUT LATEST HRRR IS ACTUALLY AGREEING WITH THE
SPCWRF/NMM IN THAT THE GREATEST THREAT MAY BE BETWEEN 10 AND
16Z...WITH NOT MUCH HAPPENING BEYOND THAT.
/OUTLOOK FOR KMSP/
FRI...VFR. WINDS NW 15G25KT.
SAT...VFR. WINDS NW 5-10KT.
SUN...VFR. WINDS SE 10KT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JPC
LONG TERM...CLF
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS DULUTH MN
319 PM CDT TUE SEP 17 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 318 PM CDT TUE SEP 17 2013
MOISTURE CONTINUED TO INCREASE FROM WEST TO EAST ACROSS THE
NORTHLAND TODAY. THE HIGH TO THE EAST WAS LOSING IT`S GRIP ON THE
NORTHLAND. A SHORTWAVE WAS MOVING NORTHEAST OUT OF IOWA AND WILL
COMBINE WITH WAA/MOISTURE ADVECTION TO CAUSE CLOUDS TO THICKEN ALL
AREAS TONIGHT AND BRING A CHANCE FOR RAIN. THE RAP WAS DOING A
GOOD JOB DEPICTING THE CLOUDS OVER OUR WESTERN CWA AND THEY SHOW
INCREASING HUMIDITY ACROSS MUCH OF THE AREA BY 06Z. RAIN WILL BE
POSSIBLE TONIGHT...AND WE INCREASED POPS OVER OUR FAR SOUTHERN CWA
WHICH WILL HAVE THE BEST CHANCE AT SEEING UP TO A TENTH OF AN INCH
OVERNIGHT. PWAT VALUES ARE EXPECTED TO RISE TO 1 TO 1.4 INCHES
OVERNIGHT...AND WE EXPECT AREAS OF FOG TO FORM. MOST AREAS SHOULD
NOT EXPERIENCE DENSE FOG...WITH THE EXCEPTION OF AREAS AROUND LAKE
SUPERIOR LATE TONIGHT WHICH COULD SEE SOME PATCHY DENSE FOG. SURFACE
DEWPOINTS ARE EXPECTED TO RISE INTO THE FIFTIES...AND WERE ALREADY
50 TO 55 FROM KINL TO KGPZ TO KAIT AND POINTS WEST. WE KEPT THE
MENTION OF DRIZZLE TONIGHT FOR MOST AREAS...ALTHOUGH WE DON`T
THINK IT WILL BE WIDESPREAD GIVEN UPSTREAM CONDITIONS. AREAS
AROUND THE LAKE WILL HAVE A BETTER CHANCE AND IT COULD BE
WIDESPREAD LATE TONIGHT INTO WEDNESDAY MORNING.
STABILITY GRADUALLY LOWERS TONIGHT...AND WE ADDED A SLIGHT CHANCE
FOR A THUNDERSTORM ACROSS THE SOUTH LATE. WAA WILL CONTINUE
WEDNESDAY...WITH A SHORTWAVE RIDGE ALOFT MOVING THROUGH EARLY.
WE HAVE A CHANCE FOR MORE SHOWERS/STORMS OVER ALL BUT FAR
NORTHWEST AREAS ON WEDNESDAY...WITH THE BEST CHANCE OCCURRING
EARLY. CLOUDS WILL SLOWLY DIMINISH OVER WESTERN AREAS...BUT
SHOULD REMAIN THROUGH MOST OF THE DAY AROUND LAKE SUPERIOR AND
OVER NORTHWEST WISCONSIN. HIGHS WILL RANGE FROM THE MID SIXTIES TO
MID SEVENTIES ACROSS THE NORTHLAND...WARMEST SOUTHWEST...COOLEST
AROUND LAKE SUPERIOR.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 318 PM CDT TUE SEP 17 2013
THE FIRST FEW DAYS OF THIS PERIOD WILL BE STORMY AND WET THEN BECOME
CHILLY WITH A STRONG COLD FRONTAL PASSAGE.
STRONG WAA THAT WILL BE ONGOING AHEAD OF AN APPROACHING COLD FRONT
WILL CONTINUE CLOUDS WEDNESDAY NIGHT. KEPT IN CHANCE OF SHOWERS
AND THUNDERSTORMS WEDNESDAY NIGHT...BUT VERY WARM MID LEVEL TEMPS
MAY PROHIBIT STORM FORMATION. BOTH THE NAM AND GFS SHOW SURGE OF 7H
10+C TEMPS. MUCH BETTER CHANCE OF THUNDERSTORMS WILL BE THURSDAY AS
A STRONG COLD FRONT APPROACHES THE AREA FROM THE WEST. THE NAM MAY BE
A BIT FASTER...BUT THE MODELS ARE IN PRETTY GOOD AGREEMENT WITH
MOVEMENT OF THE FRONT AND RESULTING QPF. DURING THE DAY THE
ATMOSPHERE DESTABILIZES IN THE STRONG WAA REGIME AND WILL BE PRIMED
FOR STORMS WHEN THE FRONT ARRIVES IN THE AFTERNOON/EARLY EVENING
EVENING. LIL`S FORECAST DOWN TO -6 AND MUCAPES UP TO 2500 J/KG. AN
EXTRA BOOST OF LIFT WILL BE PROVIDED BY AN UPPER LEVEL JET AND
S/WV.
STRONG COLD AIR WILL STREAM INTO THE REGION BEHIND THE FRONT FOR THE
FRIDAY...BUT AS HIGH PRESSURE BUILDS INTO THE REGION THE WEEKEND
WILL HAVE SUNSHINE BUT COOLER TEMPS. THIS WILL BE FOLLOWED BY
ANOTHER LOW PRESSURE/COLD FRONT ON FROM EARLY THROUGH MID WEEK WITH
A STRONG UPPER LEVEL TROF/CLOSED LOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1229 PM CDT TUE SEP 17 2013
MVFR CIGS WILL CONTINUE TO COVER THE WESTERN PART OF THE FORECAST
AREA THIS AFTERNOON....AND THESE CLOUDS WILL SPREAD ACROSS THE
REST OF THE AREA LATE THIS AFTERNOON AND EARLY EVENING. AFTER
SUNSET CIGS WILL LOWER CONSIDERABLY AND MUCH OF THE AREA WILL BE
IN IFR CONDITIONS..MAINLY DUE TO CIGS. HOWEVER...LATE TONIGHT AS MORE
MOISTURE SURGES INTO THE AREA...PATCHY DENSE FOG AND RAIN WILL
DEVELOP.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 53 65 62 74 / 20 20 50 70
INL 54 74 60 71 / 10 10 50 60
BRD 58 77 65 74 / 20 20 50 60
HYR 54 73 62 76 / 40 40 40 70
ASX 54 71 59 78 / 30 30 40 70
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...MELDE
LONG TERM...CLC
AVIATION...CLC
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1258 PM CDT Tue Sep 17 2013
.SHORT TERM: (Through Late This Afternoon)
Issued at 303 AM CDT Tue Sep 17 2013
Synoptic pattern over the region today will be dominated by broad
WAA overrunning the cooler Canadian airmass that backed into the
area Monday and overnight, which should certainly generate showers
and a few thunderstorms today in the northwest half of the CWA.
However, other than lead shortwave responsible for the light echoes
in se MO attm (which is outrunning better moisture) and some 850mb
theta-e advection vaguely focused over our n counties this morning,
mechanisms for precip are rather ill-defined. The lack of a
well-defined precip structure in the early morning regional radar
imagery is indicating the rather diffuse nature of the lift.
Plan to maintain broad PoP trends in current forecast with likely
POPS in our northwest counties to chance PoPs in se MO, although
specific numbers in a few locations will be changing to reflect
latest radar trends. In our e counties couldn`t rule out a few
sprinkles early today, but chances of measurable precip here look
low attm. Will make a last minute call on this.
Other concern for today is how warm to go on high temperatures, as
residual cool air and scattered showers will at least partially
offset warming due to the WAA. Still working on specifics but most
areas should remain in the 70s, with the coolest temps over the
northwest counties where clouds will be thickest and threat of
showers should be highest.
Truett
.LONG TERM: (Tonight through Monday)
Issued at 303 AM CDT Tue Sep 17 2013
Isolated to scattered SHRA/TSRA may continue percolating tonight due
to isentropic ascent along the 300-305 K surface, with the highest
precip chances across northeast MO and west central IL. Once the
second of two shortwaves (which were located over KS and OK early
this morning) and a warm front finally lift northeastward tonight,
precipitation should also lift away from the area.
Early morning water vapor imagery along and recent RUC 1.5 PVU
analyses depicted a strong vort max located just off the northern
CA coast. This feature is forecast to cross the Rockies and induce
surface cyclogenesis over SD/ND tomorrow, although it will also
influence conditions over MO/IL by producing weakly diffluent
southwesterly flow aloft. Between general moistening of the air
mass (PW values rise to around 1.7 inches by Wed night),
increasing H7-H5 lapse rates, and nocturnal LLJ activity, it`s
hard to rule out disorganized iso-sct precip for Wed and Wed
night, particularly across the northern and northeastern CWA. In
terms of the aforementioned low pressure system which will be
moving along the US/Canadian border and into southern Canada by
Thu night, models remain in general agreement with the overall
pattern despite some differences after 20/00z regarding a piece of
energy that breaks off near the base of the trough and then moves
across MO on Fri night. The cold front is forecast to approach the
CWA on Thu night and then move through on Fri/Fri night. Low level
convergence with the front, large scale ascent ahead of the upper
level trough axis, and favorable positioning beneath the right
entrance region of a jet at H25 all support likely PoPs for Thu
night and Fri across parts of the CWA. Precipitation is expected
to end from northwest to southeast due to post-frontal subsidence.
17/00z runs of the ECMWF/GFS/GEM all agree that a surface high
pressure center will build into the Great Lakes this weekend and
that there will be some degree of upper ridging over the Plains
ahead of the next progressive trough near the West Coast, but each
model has a different take on the upper level pattern east of the
Mississippi River with potential impacts for the MO/IL forecast.
The GFS depicts a closed low over the OH valley, the GEM brings a
tropical low northward from the Gulf of Mexico, and the ECMWF has
a weak upper trough axis oriented from LA through GA and into VA.
Since there is little confidence in any particular solution at
this time, the forecast grids for Sat-Mon generally reflect the
recommended CR initialization.
Kanofsky
&&
.AVIATION: (For the 18z TAFs through 18z Wednesday Afternoon)
Issued at 1241 PM CDT Tue Sep 17 2013
Area of rain and lower CIGS/VSBYS over central Missouri will
continue to spread into parts of eastern/northeast Missouri and
west central Illinois. Not expecting flight conditions to fall
below MVFR as the precipitation continues to weaken, but CIGS will
likely occasionally fall below 2000FT. Expecting the weakening
trend to continue through the weekend with little or no precip
crossing the Mississippi river into southwest Illinois. Should see
CIGS rise above 3000FT later this afternoon into the evening.
Another wave of showers is expected to develop late tonight which
could bring flight conditions back down to MVFR for early
Wednesday morning.
Specifics for KSTL:
The area of rain over central Missouri is expected to continue
weakening this afternoon, so am expecting little if any
precipitation to reach Lambert. Should see VFR flight conditions
continue at least through 06Z-08Z. However, another batch of rain
is expected to develop over central Missouri late tonight, and
this may bring CIGS down after 09Z. Confidence is low however, so
have not lowered CIGS substantially in the TAF. Expect that if the
CIGS do drop below VFR, conditions should improve after 12Z-14Z
Wednesday.
Carney
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
704 AM CDT Tue Sep 17 2013
.SHORT TERM: (Through Late This Afternoon)
Issued at 303 AM CDT Tue Sep 17 2013
Synoptic pattern over the region today will be dominated by broad
WAA overrunning the cooler Canadian airmass that backed into the
area Monday and overnight, which should certainly generate showers
and a few thunderstorms today in the northwest half of the CWA.
However, other than lead shortwave responsible for the light echoes
in se MO attm (which is outrunning better moisture) and some 850mb
theta-e advection vaguely focused over our n counties this morning,
mechanisms for precip are rather ill-defined. The lack of a
well-defined precip structure in the early morning regional radar
imagery is indicating the rather diffuse nature of the lift.
Plan to maintain broad PoP trends in current forecast with likely
POPS in our northwest counties to chance PoPs in se MO, although
specific numbers in a few locations will be changing to reflect
latest radar trends. In our e counties couldn`t rule out a few
sprinkles early today, but chances of measurable precip here look
low attm. Will make a last minute call on this.
Other concern for today is how warm to go on high temperatures, as
residual cool air and scattered showers will at least partially
offset warming due to the WAA. Still working on specifics but most
areas should remain in the 70s, with the coolest temps over the
northwest counties where clouds will be thickest and threat of
showers should be highest.
Truett
.LONG TERM: (Tonight through Monday)
Issued at 303 AM CDT Tue Sep 17 2013
Isolated to scattered SHRA/TSRA may continue percolating tonight due
to isentropic ascent along the 300-305 K surface, with the highest
precip chances across northeast MO and west central IL. Once the
second of two shortwaves (which were located over KS and OK early
this morning) and a warm front finally lift northeastward tonight,
precipitation should also lift away from the area.
Early morning water vapor imagery along and recent RUC 1.5 PVU
analyses depicted a strong vort max located just off the northern
CA coast. This feature is forecast to cross the Rockies and induce
surface cyclogenesis over SD/ND tomorrow, although it will also
influence conditions over MO/IL by producing weakly diffluent
southwesterly flow aloft. Between general moistening of the air
mass (PW values rise to around 1.7 inches by Wed night),
increasing H7-H5 lapse rates, and nocturnal LLJ activity, it`s
hard to rule out disorganized iso-sct precip for Wed and Wed
night, particularly across the northern and northeastern CWA. In
terms of the aforementioned low pressure system which will be
moving along the US/Canadian border and into southern Canada by
Thu night, models remain in general agreement with the overall
pattern despite some differences after 20/00z regarding a piece of
energy that breaks off near the base of the trough and then moves
across MO on Fri night. The cold front is forecast to approach the
CWA on Thu night and then move through on Fri/Fri night. Low level
convergence with the front, large scale ascent ahead of the upper
level trough axis, and favorable positioning beneath the right
entrance region of a jet at H25 all support likely PoPs for Thu
night and Fri across parts of the CWA. Precipitation is expected
to end from northwest to southeast due to post-frontal subsidence.
17/00z runs of the ECMWF/GFS/GEM all agree that a surface high
pressure center will build into the Great Lakes this weekend and
that there will be some degree of upper ridging over the Plains
ahead of the next progressive trough near the West Coast, but each
model has a different take on the upper level pattern east of the
Mississippi River with potential impacts for the MO/IL forecast.
The GFS depicts a closed low over the OH valley, the GEM brings a
tropical low northward from the Gulf of Mexico, and the ECMWF has
a weak upper trough axis oriented from LA through GA and into VA.
Since there is little confidence in any particular solution at
this time, the forecast grids for Sat-Mon generally reflect the
recommended CR initialization.
Kanofsky
&&
.AVIATION: (For the 12z TAFs through 12z Wednesday Morning)
Issued at 640 AM CDT Tue Sep 17 2013
As mentioned in the short term discussion, projected precip
pattern across the CWA is a bit chaotic today. However, feel the
greatest coverage of showers and scattered thunderstorms this
morning will be in the zone of strongest WAA/isentropic lift over
northwest parts of the CWA, and affecting the COU and UIN tafs.
Have attempted to time onset of TEMPO shower groups to leading
edge of echoes currently stretching from west central into
southwest MO. Meanwhile, only a few hit and miss showers are
expected for STL metro area tafs during the morning. Have omitted
TS for now as radar/satellite imagery and latest guidance don`t
offer any strong indications of an imminent threat at any of our
forecast points. As far as ceilings are concerned...looks like
MVFR and IFR that blankets the western half of Missouri will have
a tough time migrating too far east due to strong easterly
component to low level flow. Have held onto MVFR cigs 2-3kft at
COU throughout the morning, with ceilings lifting aoa 3kft no
later than midday. Ceilings elsewhere should be AOA 4kft
today...rising to a mid cloud deck tonight.
Specifics for KSTL: Ceilings around 4kft are expected today with
a few hit and miss showers during the morning that should
generally be on the light side. By tonight, forecast soundings
indicate mid and high level cloudiness.
Truett
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
325 AM CDT Tue Sep 17 2013
.SHORT TERM: (Through Late This Afternoon)
Issued at 303 AM CDT Tue Sep 17 2013
Synoptic pattern over the region today will be dominated by broad
WAA overrunning the cooler Canadian airmass that backed into the
area Monday and overnight, which should certainly generate showers
and a few thunderstorms today in the northwest half of the CWA.
However, other than lead shortwave responsible for the light echoes
in se MO attm (which is outrunning better moisture) and some 850mb
theta-e advection vaguely focused over our n counties this morning,
mechanisms for precip are rather ill-defined. The lack of a
well-defined precip structure in the early morning regional radar
imagery is indicating the rather diffuse nature of the lift.
Plan to maintain broad PoP trends in current forecast with likely
POPS in our northwest counties to chance PoPs in se MO, although
specific numbers in a few locations will be changing to reflect
latest radar trends. In our e counties couldn`t rule out a few
sprinkles early today, but chances of measurable precip here look
low attm. Will make a last minute call on this.
Other concern for today is how warm to go on high temperatures, as
residual cool air and scattered showers will at least partially
offset warming due to the WAA. Still working on specifics but most
areas should remain in the 70s, with the coolest temps over the
northwest counties where clouds will be thickest and threat of
showers should be highest.
Truett
.LONG TERM: (Tonight through Monday)
Issued at 303 AM CDT Tue Sep 17 2013
Isolated to scattered SHRA/TSRA may continue percolating tonight due
to isentropic ascent along the 300-305 K surface, with the highest
precip chances across northeast MO and west central IL. Once the
second of two shortwaves (which were located over KS and OK early
this morning) and a warm front finally lift northeastward tonight,
precipitation should also lift away from the area.
Early morning water vapor imagery along and recent RUC 1.5 PVU
analyses depicted a strong vort max located just off the northern
CA coast. This feature is forecast to cross the Rockies and induce
surface cyclogenesis over SD/ND tomorrow, although it will also
influence conditions over MO/IL by producing weakly diffluent
southwesterly flow aloft. Between general moistening of the air
mass (PW values rise to around 1.7 inches by Wed night),
increasing H7-H5 lapse rates, and nocturnal LLJ activity, it`s
hard to rule out disorganized iso-sct precip for Wed and Wed
night, particularly across the northern and northeastern CWA. In
terms of the aforementioned low pressure system which will be
moving along the US/Canadian border and into southern Canada by
Thu night, models remain in general agreement with the overall
pattern despite some differences after 20/00z regarding a piece of
energy that breaks off near the base of the trough and then moves
across MO on Fri night. The cold front is forecast to approach the
CWA on Thu night and then move through on Fri/Fri night. Low level
convergence with the front, large scale ascent ahead of the upper
level trough axis, and favorable positioning beneath the right
entrance region of a jet at H25 all support likely PoPs for Thu
night and Fri across parts of the CWA. Precipitation is expected
to end from northwest to southeast due to post-frontal subsidence.
17/00z runs of the ECMWF/GFS/GEM all agree that a surface high
pressure center will build into the Great Lakes this weekend and
that there will be some degree of upper ridging over the Plains
ahead of the next progressive trough near the West Coast, but each
model has a different take on the upper level pattern east of the
Mississippi River with potential impacts for the MO/IL forecast.
The GFS depicts a closed low over the OH valley, the GEM brings a
tropical low northward from the Gulf of Mexico, and the ECMWF has
a weak upper trough axis oriented from LA through GA and into VA.
Since there is little confidence in any particular solution at
this time, the forecast grids for Sat-Mon generally reflect the
recommended CR initialization.
Kanofsky
&&
.AVIATION: (For the 06z TAFs through 06z Tuesday Night)
Issued at 1154 PM CDT Mon Sep 16 2013
Mid and high clouds persist over area with mvfr cigs just west
and southwest of forecast area as of 0430z. Will see the mvfr cigs
slowly make their way to the northeast towards taf sites. Taf
sites along I-70 corridor to see cigs lower to mvfr between 08z-
11z Tuesday. Otherwise, trying to figure out timing and coverage
of showers and possibly a few thunderstorms. Activity over eastern
KS, western MO to continue to develop and slide east, reaching
central MO by 14z and west central IL by 19z. For now just kept
vcnty shower mention. Not sure it will hold together and reach STL
metro area, so kept those tafs dry for now. MVFR cigs to lift and
scatter out by midday. As for winds, east winds to veer over time
to the southeast, then eventually to the south as surface ridge
moves off to the east.
Specifics for KSTL:
Mid and high clouds persist over area with mvfr cigs just west
and southwest of forecast area as of 0430z. Will see the mvfr cigs
slowly make their way to the northeast towards metro area. Cigs
to lower to mvfr by 11z Tuesday. Otherwise, trying to figure out
timing and coverage of showers and possibly a few thunderstorms.
Activity over eastern KS, western MO to continue to develop and
slide east. Not sure it will hold together and reach STL metro
area, so kept KSTL dry for now. MVFR cigs to lift and scatter out
by 16z Tuesday. As for winds, east winds to veer to the
south by 16z Tuesday as surface ridge moves off to the east.
Byrd
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
315 PM CDT TUE SEP 17 2013
.DISCUSSION...
SHORT TERM CONCERNS ARE MAINLY CLOUD COVER INTO WEDNESDAY MORNING
AND TEMPERATURES THE NEXT FEW DAYS.
12Z UPPER AIR CHARTS SHOWED THE FOLLOWING. AT 300 MB...JETSTREAM
AXIS EXTENDED FROM BASE OF THE TROUGH RIGHT ALONG THE WEST COAST
NORTHEASTWARD ACROSS THE ROCKIES AND INTO MANITOBA. AT 500 MB...ONE
AREA OF GREATER THAN 30 METER HEIGHT FALLS EXTENDED FROM CANADA DOWN
INTO MO. MORE SIGNIFICANT FALLS (60-90 METERS) WERE JUST AHEAD OF
THE TROUGH OVER NORTHERN CA...SOUTHERN OR AND INTO NV. DECENT
MOISTURE WAS NOTED FROM NRN MEXICO UP INTO THE CENTRAL PLAINS AT
AND BELOW 700 MB. EARLY AFTN WATER VAPOR IMAGERY SHOWED DRYING
MOVING ACROSS THE PLAINS BETWEEN THE TWO SHORTWAVES. EARLY AFTN
SURFACE ANALYSIS SHOWED MODEST SOUTHERLY FLOW IN PLACE OVER THE
AREA WITH DEWPOINTS IN THE 50S AND 60S.
TONIGHT...EXPECT SOME DECREASE IN OVERALL CLOUD COVER. FORECAST
SOUNDINGS SHOW SOME ELEVATED INSTABILITY THIS EVENING ALONG WITH
DECENT MID LEVEL LAPSE RATES. LATEST RUNS OF THE RAP DEVELOP SOME
PCPN ACROSS ABOUT THE EASTERN 1/2 OF MY AREA. 12Z GFS DID TOO.
SO WILL INCLUDE A SMALL CHANCE FOR TSTMS PRIOR TO 09Z. WITH
SUBSTANTIAL LOW LEVEL MOISTURE REMAINING IN PLACE AFTER HIGHER
CLOUDS CLEAR OUT...HAVE SOME CONCERN THAT STRATUS MAY REFORM. WE
MAY ALSO HAVE SOME FOG BUT IT APPEARS TO BE LESS OF A CONCERN FOR
THE PUBLIC FORECAST DUE TO WINDS MOSTLY ABOVE 7 KNOTS.
WEDNESDAY...SOUTHERLY FLOW WILL INCREASE AS MIXING DEPTH INCREASES
THROUGH THE MORNING...WITH BREEZY/WINDY CONDITIONS BY AFTN. 850 MB
TEMPERATURES WILL INCREASE SUBSTANTIALLY COMPARED TO TODAY (INTO THE
19-22 DEGREE CELSIUS RANGE BY 00Z THURSDAY)...SO HIGHS IN THE
UPPER 80S TO AROUND 90 SEEM LIKELY.
SYSTEM FOR WEDNESDAY NIGHT INTO THURSDAY SEEMS TO HAVE SLOWED DOWN A
BIT SO DID MAKE SOME ADJUSTMENTS FOR PCPN TIMING IN THOSE PERIODS.
COLD FRONT SHOULD ENTER OUR FAR NORTHWEST COUNTIES BETWEEN 06Z AND
09Z THURSDAY THEN EXIT THE SOUTHEAST COUNTIES BETWEEN 21Z THURSDAY
AND 00Z FRIDAY. BOOSTED PCPN CHANCES A BIT FOR THURSDAY...BUT IT NOW
APPEARS THE SYSTEM WILL EXIT SOONER THURSDAY NIGHT BASED ON A BLEND
OF GFS/NAM/SREF/ECMWF/GEM.
THE PERIOD FROM FRIDAY THROUGH SUNDAY SHOULD BE DRY...WITH HIGHS IN
THE 70S TO AROUND 80. 500 MB TROUGH WILL BE SHIFTING EAST OF THE
AREA FRIDAY...WITH RIDGING OVER THE ROCKIES AND ANOTHER TROUGH OFF
THE WEST COAST. FLOW WILL BE PROGRESSIVE IN THIS PERIOD...WITH THE
NEXT CHANCE OF PCPN MOVING IN BY SUNDAY NIGHT AS THE SYSTEM DIGS
OVER THE ROCKIES. DIFLUENT FLOW ALONG WITH INCREASING MOISTURE
AHEAD OF THE NEXT COLD FRONT SHOULD BRING SOME SHOWERS AND TSTMS
FROM SUNDAY NIGHT THROUGH MONDAY NIGHT.
MILLER
&&
.AVIATION...
18Z TAFS FOR KOMA...KLNK...AND KOFK.
IFR CONDITIONS CONTINUE ACROSS THE TAF SITES THIS AFTERNOON.
SHOWERS HAVE CLEARED THE SITES...BUT CEILINGS ARE SLOW TO IMPROVE
TODAY AS LOW-LEVEL MOISTURE LINGERS. INCREASED SOUTHERLY FLOW
SHOULD HELP ERODE STRATUS DECK FROM THE WEST AND THE SOUTH FROM
LATE AFTERNOON INTO THIS EVENING...BUT CANNOT RULE OUT THE
POSSIBILITY THAT THE STRATUS DECK WILL SOCK IN LONGER THAN CURRENT
FORECAST INDICATES. WINDS WILL REMAIN AROUND 10-12KT
OVERNIGHT...WHICH SHOULD BE ENOUGH TO HELP ALLEVIATE WIND SHEAR
CONCERNS...AND WHICH ALSO SHOULD BE ENOUGH TO DETER FOG FORMATION.
EVEN SO...HAVE INCLUDED AN MVFR VIS GROUP AT ALL SITES LATE
TONIGHT AS CLEARING OCCURS...AS GUIDANCE IS UNANIMOUSLY INDICATING
AT LEAST SOME EXTENT OF REDUCED VIS. VIS WILL IMPROVE AS WINDS
INCREASE THROUGH THE MORNING...WITH GUSTY SOUTH WINDS DEVELOPING
BY MID-MORNING.
MAYES
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
548 PM MDT WED SEP 18 2013
.AVIATION...
00Z TAF CYCLE
MTS OCCASIONALLY OBSCURED. SCT CONVECTION TO PERSIST AND MOVE
GENLY NORTHEAST TO EAST OVER NRN AND CENTRAL NM THROUGH 06Z...WITH
ISOLD CONVECTION POSSIBLE INTO THE OVERNIGHT HOURS AS UPPER
DISTURBANCE TRACKS EAST OVER THE REGION. LOCALIZED MVFR CIGS/VSBYS
IN TSRA WILL BE POSSIBLE ALONG WITH SMALL HAIL AND SFC WND GUSTS
TO 35KT. LOCAL MVFR CIGS POSSIBLE FROM THE CENTRAL MT CHAINS
ACROSS THE EASTERN PLAINS AFT 06Z TO AROUND 15Z THURSDAY. SFC FRONT TO
APPROACH FAR NE NM BY 15Z THURSDAY.
&&
.PREV DISCUSSION...256 PM MDT WED SEP 18 2013...
ANOTHER ACTIVE WX SCENARIO SHAPING UP OVER THE REGION FOR REMAINDER
OF TODAY THRU THURSDAY. CIRA LAYERED TOTAL PW PRODUCT SHOWS ABUNDANT
LOW/MID LEVEL MOISTURE ACROSS THE REGION WITH VERY DRY CONDITIONS
ALOFT. VALUES ARE ON THE ORDER OF 130-160 PCT OF NORMAL. A THIN 30-
50 KT UPPER JET AXIS OVER NM AS SEEN ON THE LATEST AMDAR DATA IS
INTERACTING WITH THE LOW LEVEL MOISTURE AND INSTABILITY TO PRODUCE
A WELL DEFINED BAND OF THUNDERSTORMS OVER WESTERN AND NORTHERN NM.
STEERING FLOWS ARE STRONG TODAY HOWEVER THE SHEAR AXIS IS ORIENTED
IN THE DRXN OF STORM MOTION SO MORE LOCALLY HEAVY RAINFALL ON TAP.
LATEST HRRR SHOWS THIS AREA OF SHOWERS AND STORMS PROPAGATING EVER
SO SLOWLY EAST THIS EVENING INTO THE RIO GRANDE VALLEY AND NEARBY
HIGH TERRAIN. HAVE RAISED POPS TO HIGH CHANCE AND LIKELY FOR CENTRAL
NM.
EVEN MORE ACTIVE CONDITIONS WILL TAKE SHAPE INTO THURSDAY NIGHT BUT
MORE INTO THE EASTERN PLAINS. A LARGE UPPER TROUGH OVER THE PACIFIC
NW WILL SLIDE EAST INTO THE GREAT PLAINS AND HELP DRIVE A SURFACE
BACK DOOR FRONTAL BOUNDARY INTO NM. MEANWHILE...A VERY WELL DEFINED
UPPER WAVE EMBEDDED ON THE BACK SIDE OF THE LARGE SCALE WAVE WILL
SLIDE OVER NORTHERN NM AND HELP LIFT FOCUS OVER FRONT. CURRENT QPF
VALUES ARE POTENTIALLY TOO LOW FOR THIS EVENT ACROSS THE EAST WHERE
SUBSTANTIALLY MOISTURE REMAINS IN PLACE. FLOODING IS NOT EXPECTED
HOWEVER SOME LOCALIZED IMPACTS ARE LIKELY IF THE RAIN FALLS OVER
THE WRONG SPOT. ALSO RAISED POPS FOR THE EASTERN PLAINS THURSDAY
NIGHT TO LIKELY. TEMPS THROUGH THIS PERIOD WILL COOL BELOW NORMAL
FOR MUCH OF THE REGION...ESPECIALLY THE EAST.
MODELS DO INDICATE STRONGER WESTERLIES AND DRIER AIR SHIFTING EAST
INTO THE STATE FRIDAY THRU SUNDAY HOWEVER STRONG MOISTURE RECYCLING
PROCESSES WILL STILL BE AT PLAY. LOW CLOUDS AND FOG ARE POSSIBLE
ANY NIGHT ESPECIALLY IF SKIES CLEAR AND WINDS TAPER OFF. TEMPS WILL
BE COOL OUT WEST WHERE MUCH DRIER DEWPOINTS WILL MOVE IN. THE
EXTENDED PATTERN IS STILL HIGHLY UNCERTAIN SO MADE NO CHANGES. THE
ECMWF PROGS A DEEP LARGE SCALE STATIONARY UPPER LOW OVER THE GREAT
BASIN WITH A RELATIVELY ABUNDANT MONSOONAL MOISTURE TAP OVER NM. THE
GFS HAS AN EVEN DEEPER TIGHTLY WOUND COLD UPPER LOW DRIVING EAST
ACROSS THE CENTRAL ROCKIES THRU MID WEEK.
GUYER
&&
.FIRE WEATHER...
SCATTERED WETTING THUNDERSTORMS FOUND ACROSS WESTERN AND NORTHERN
AREAS WILL TRANSITION EASTWARD THIS EVENING BEFORE DIMINISHING SOME.
DRIER AIR WILL EVENTUALLY FILL IN FROM WEST TO EAST LATER TONIGHT
AND WILL SET THE STAGE FOR A DRIER WESTERN AND CENTRAL AREAS ON
THURSDAY.
A BACK DOOR COLD FRONT IS STILL EXPECTED FOR THURSDAY WITH EASTERN
AREAS OBSERVING THAT INFLUENCE. THIS INCLUDES WETTING SHOWERS AND
THUNDERSTORMS WHICH WOULD FAVOR MOST OF THE EASTERN PLAINS THURSDAY
AFTERNOON INTO THE OVERNIGHT. MIXING HEIGHTS WILL INCREASE ACROSS
THE MAJORITY OF THE AREA ALTHOUGH TRANSPORT WINDS WILL COME DOWN
MOST AREAS SO VENTILATION RATES WILL LOWER PRETTY MUCH AREAWIDE.
THE BACK DOOR COLD FRONT WILL PUSH THROUGH THE CENTRAL MOUNTAINS
THURSDAY NIGHT AND MOST LIKELY MAKE IT TO THE AZ STATE LINE BY
FRIDAY MORNING. MIXING DURING FRIDAY AFTERNOON SHOULD SET UP A
CONVERGENCE BOUNDARY NEAR THE CONTINENTAL DIVIDE AND MOST LIKELY
PROVIDE A FOCUS FOR THUNDERSTORMS THERE. THE ATMOSPHERE COULD BE TOO
STABLE FOR SIGNIFICANT SHOWER AND THUNDERSTORM DEVELOPMENT ACROSS
CENTRAL AND EASTERN AREAS DUE TO RESIDUAL IMPACTS FROM THE COLD
FRONT. HUMIDITY VALUES WILL BE UNSEASONABLY HIGH FRIDAY AFTERNOON.
TEMPERATURES WILL BE COOLER THAN NORMAL CENTRAL AND EASTERN AREAS
WHILE BEING NEAR NORMAL WEST OF THE CONTINENTAL DIVIDE. VENTILATION
RATES WILL BE LOWEST EXTENDING FROM ZONE 109 NORTHEASTWARD OVER THE
MIDDLE RIO GRANDE VALLEY AND AREAS TO THE LEE OF THE SANGRE DE
CRISTOS.
THE NEXT PACIFIC TROUGH WILL PLUNGE INTO THE FAR WESTERN US SATURDAY
AND CONTINUE TO TRAVERSE ACROSS THE INTERMOUNTAIN WEST ON SUNDAY.
MOISTURE WILL TRY TO SEEP UP FROM MEXICO AHEAD OF THIS TROUGH SO
LOOK FOR UNSETTLED WEATHER ACROSS THE WEST ON SATURDAY TRANSITIONING
SOME EASTWARD ON SUNDAY. WETTING RAIN WOULD CERTAINLY BE POSSIBLE
ALTHOUGH NOT AS WIDESPREAD AS THE PREVIOUS WEEK. HUMIDITY IS
EXPECTED TO TREND UP ACROSS THE WEST ON SATURDAY WHILE LOWER ACROSS
THE EAST. ON SUNDAY...HUMIDITY IS EXPECTED TO LOWER AREAWIDE
ALTHOUGH THIS COULD CHANGE. VENTILATION WILL INCREASE DURING THE
WEEKEND THANKS TO STRONGER WEST/SOUTHWEST TRANSPORT WIND. CONFIDENCE
IS PRETTY GOOD THAT A PACIFIC TROUGH WILL IMPACT THE AREA BUT STILL
NOT TOTALLY SURE ABOUT HOW MUCH MOISTURE WILL SEEP UP FROM THE SOUTH
AND FEED THE TROUGH. SURFACE WIND SHOULD ALSO INCREASE DURING THE
WEEKEND PERIOD.
ANOTHER PACIFIC TROUGH IS EXPECTED TO AFFECT THE WESTERN US BY THE
MIDDLE OF NEXT WEEK. THE LONG RANGE MODELS DIFFER SOMEWHAT IN THE
EXTENSION SOUTHWARD OF THE TROUGH BUT EITHER WAY IMPACT POTENTIAL
WOULD INCREASE BY MID NEXT WEEK. DEPENDING ON HOW THE TROUGH COMES
IN...ADDITIONAL WETTING RAIN WOULD BE POSSIBLE. CONDITIONS FOLLOWING
THE TROUGH PASSAGE COULD LEAD TO THE MOUNTAINS FIRST BIG FREEZE OF
THE FALL SEASON SO WILL BE WATCHING THAT AS THAT WOULD BEGIN THE
CURING PROCESS TO THE ABUNDANT FUELS THAT HAVE GREENED UP THIS SUMMER.
50
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS RALEIGH NC
620 AM EDT TUE SEP 17 2013
.SYNOPSIS...
HIGH PRESSURE BUILDS OVER THE REGION TODAY BEHIND A COLD FRONT. THE
HIGH WILL REMAIN OVER THE REGION INTO THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 620 AM TUESDAY...
WITH THE SURFACE FRONT NOW WELL SOUTH OF CENTRAL NORTH CAROLINA...
DRIER MID-LEVEL AIR HAD MOVED INTO THE AREA FROM THE NORTH ON WATER
VAPOR IMAGERY. PRECIPITABLE WATER VALUES FALL TO A HALF-INCH OR LESS
BY TONIGHT...AS K INDICES FALL INTO MOSTLY NEGATIVE VALUES. FOR
TODAY...THE SURFACE GRADIENT TIGHTENS AS HIGH PRESSURE BUILDS
SOUTH...WITH BOTH THE NAM AND THE GFS BUFR SOUNDINGS SUGGESTING...
WITH MIXING...SURFACE WIND GUSTS FROM THE UPPER TEENS TO LOWER 20S
KTS COURTESY OF THE GRADIENT AND A 925MB WIND OF 20 TO 25KT EARLY
THIS MORNING. GUSTINESS SHOULD WANE DURING THE AFTERNOON AS THE
925MB WINDS DIMINISH TO 10 TO 15KT BY 00Z WEDNESDAY. THE 00Z TUESDAY
UPPER-AIR ANALYSIS SHOWED DECENT 850MB MOISTURE ACROSS MUCH OF THE
EASTERN SEABOARD...AND THE 00Z NAM BUFR SOUNDINGS SUGGESTED DECENT
850MB MOISTURE IN PLACE PROVIDING FOR THE LIKELIHOOD OF AT LEAST
SCATTERED CU/SC DURING THE DAY. ON THE OTHER HAND...THE GFS IS MUCH
DRIER AND CAPPED AT 850MB...AND THE LATEST NAM AND RAP BOTH ARE A
LITTLE LESS ROBUST WITH THE LOW-LEVEL MOISTURE...INCREASING THE
POTENTIAL FOR SOME HIGH-BASED CU OR SC LATER IN THE DAY AFTER
MORNING CLOUDS ERODE. THE CANADIAN CLOUD COVER MODEL IS SIMILAR...
AND LEANING THIS PARTLY TO MOSTLY CLOUDY CONDITIONS DURING THE VERY
EARLY MORNING SHOULD IMPROVE TO CONSIDERABLE SUNSHINE...WITH AREAS
OF PARTLY SUNNY CONDITIONS DEVELOPING THIS AFTERNOON AS SOME 850MB
MOISTURE MOVES IN FROM THE EAST AND NORTHEAST. 1000-850MB
THICKNESSES SUGGEST HIGHS...OVERALL...NEAR THE COOLER GFS MOS
GUIDANCE...FOR MAXES MOSTLY IN THE MID TO UPPER 70S.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
AS OF 230 AM TUESDAY...
HIGH PRESSURE REMAINS IN PLACE THROUGH...AND BEYOND...THIS
SHORT-TERM PERIOD. THERE REMAINS A MODEST SURFACE GRADIENT TONIGHT...
SO DESPITE THE STRENGTH OF THE HIGH THERE SHOULD BE ENOUGH MIXING
UNDER THE INVERSION THAT WINDS SHOULD NOT GO COMPLETELY CALM...OR
COMPLETELY CALM FOR LONG. THE CLOUD FORECAST IS A LITTLE
CHALLENGING...AS THE GFS IN PARTICULAR ADVECTS SOME STRATOCU IN THE
LOW-LEVEL EASTERLY FLOW TOWARD THE COASTAL PLAIN LATE...WITH BOTH
THE NAM AND THE GFS...ALONG WITH THE CANADIAN CLOUD COVER MODEL...
SUGGESTIVE OF SOME MOSTLY THIN CIRRUS LATE FROM THE WEST AND
NORTHWEST. STAYED CLOSE TO GUIDANCE LOWS...LEANING MORE TOWARD THE
GFS AND ITS BIAS-CORRECTED MINS...FOR LOWS FROM THE UPPER 40S TOWARD
KTDF...KHNZ...AND KLHZ TO THE MID 50S OVER MUCH OF THE SANDHILLS AND
THE SOUTHERN COASTAL PLAIN. RECORD LOWS ARE ABOUT 5 DEGREES BELOW
FORECAST LOWS AT KGSO...KRDU...AND KFAY.
WEDNESDAY...AHEAD OF AN INCREASE IN POTENTIAL VORTICITY ON THE
1.5PVU SURFACE THAT BOTH THE NAM AND GFS FORECAST WEDNESDAY NIGHT...
AREAS OF HIGH CLOUDS ARE FORECAST WHICH ALSO SHOW UP ON THE CANADIAN
CLOUD COVER MODEL. WITH THAT LEVEL OF CONSISTENCY AMONG THE
GUIDANCE...WILL HAVE SKIES BECOMING PARTLY SUNNY IN THE GRIDDED
FORECAST DURING THE AFTERNOON FOR MOST LOCATIONS TURNING MOSTLY
CLEAR DURING THE EVENING. AGAIN...SUBTLE DISCREPANCIES OCCUR BETWEEN
THE NAM AND GFS THAT RESULT IN A CHALLENGING CLOUD COVER FORECAST
FOR OVERNIGHT WEDNESDAY NIGHT. THE NAM IS MUCH MORE AGGRESSIVE IN
INCREASING MID-LEVEL MOISTURE OVERNIGHT AT OR JUST ABOVE 500MB WITH
THE PASSAGE OF THE MODEST WAVE ON THE 1.5PVU SURFACE...WHILE THE GFS
IGNORES THIS AND WOULD IMPLY LIMITED CLOUD COVER. THIS HAS AN IMPACT
ON THE LOW TEMPERATURE FORECAST. UNDER A LIGHT WIND WITH THE SURFACE
RIDGE AXIS OVERHEAD...LOWS HAVE THE POTENTIAL TO BE COLDER THAN WHAT
SHOULD OCCUR TONIGHT. ON THE OTHER HAND...BOTH THE NAM AND THE GFS
MOS GUIDANCE ARE WARMER AT MOST EVERY LOCATION FOR WEDNESDAY NIGHT
COMPARED TO TONIGHT. THE GFS IS JUST ABOUT AS STRONG AS THE NAM WITH
ITS WAVE ON THE 1.5PVU SURFACE OVERNIGHT WEDNESDAY...SO WILL
ANTICIPATE AT LEAST A FEW CLOUDS MOVING THROUGH. WILL STILL FORECAST
A FEW 40S WEDNESDAY NIGHT BUT CONFINE THEM TO BASICALLY ALONG THE
VIRGINIA BORDER COUNTIES...SHOWING A DEGREE OR TWO INCREASE IN LOWS
IN MOST OTHER LOCATIONS FOR MOSTLY LOWER TO MID 50S. 1000-850MB
THICKNESSES ARE ABOUT 8M HIGHER WEDNESDAY COMPARED TO TODAY...BUT
WITH A FEW HIGH CLOUDS EXPECTED DURING THE AFTERNOON...THE MAX
TEMPERATURE FORECAST FOR WEDNESDAY IS BASICALLY PERSISTENCE FROM
TODAY.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 305 AM TUESDAY...
THU THROUGH FRI NIGHT: DEEP LAYER RIDGINGWILL CONTROL THE WEATHER
PATTERN OVER CENTRAL NC THIS PERIOD. RETURN FLOW WILL DEVELOP AROUND
THE CONTINENTAL POLAR SURFACE HIGH FORECAST TO BE CENTERED OVER THE
MIDDLE ATLANTIC STATES AT THE START OF THE PERIOD. THE COMBO OF THIS
RETURN FLOW AND SIGNIFICANT CP AIR MASS MODIFICATION BY A LATE
SUMMER SUN ANGLE WILL YIELD NEAR AVERAGE TEMPS FOR MID SEPTEMBER ON
THU. FURTHER WARMING WILL TAKE PLACE FRI IN STRENGTHENING RETURN
FLOW AND SUBSIDENCE BENEATH A 317 DM H7 RIDGE AXIS OVER THE SOUTHERN
APPALACHIANS. HIGHS IN THE MIDDLE TO UPPER 80S...OR A FEW DEGREES
WARMER THAN WHAT FORECAST LOW LEVEL THICKNESSES - WHICH HAVE YIELDED
A COOL BIAS IN RECENT WEEKS - WOULD SUGGEST. LOWS...WITH GOOD
RADIATIONAL COOLING ASSOCIATED WITH MOSTLY CLEAR AND CALM IN THE
RIDGE AXIS...ARE FORECAST ON THE COOL SIDE OF GUIDANCE - IN LINE
WITH CLIMO FOR PROJECTED LL THICKNESSES IN THE 1380 TO AROUND 1390
METER RANGE.
SAT THROUGH MON: THE FIRST IN A SERIES OF A FEW STRONG AND
PROGRESSIVE UPPER LOWS/TROUGHS FORECAST TO MIGRATE EASTWARD ACROSS
THE NORTHERN TIER OF THE CONUS/SOUTHERN CANADA WILL PROPEL AN
ACCOMPANYING SURFACE COLD FRONT FROM THE TN VALLEY EARLY SAT...TO
THE SPINE OF THE APPALACHIAN CHAIN BY SUN MORNING...WITH PRECEDING
PRE-FRONTAL TROUGHING IN THE LEE OF THE APPALACHIANS. MEDIUM RANGE
GUIDANCE...ASIDE FROM THE DISCOUNTED 00Z/17TH GFS SOLUTION...HAS
COME INTO EXCELLENT AGREEMENT REGARDING THIS EVOLUTION AND
ASSOCIATED FRONTAL PASSAGE THROUGH CENTRAL NC ON SUN. THERE HAS BEEN
A TREND TOWARD A STRONGER SOUTHERN STREAM PORTION OF THE LONGWAVE
TROUGH ALOFT...WHICH WILL LIKELY SUPPORT SOME SORT OF SURFACE
CYCLOGENESIS FROM THE NW CARIBBEAN TO THE SW ATLANTIC LATE IN THE
WEEKEND INTO EARLY NEXT WEEK. GIVEN THE PROGRESSIVE NATURE OF THE
FLOW ALOFT...HOWEVER...ANY SUCH DEVELOPMENT WOULD BE TOO FAR SOUTH
AND EAST TO AFFECT OUR AREA...WHICH IS WHY THE 00Z/17TH GFS SOLUTION
WAS DISCOUNTED AS NOTED ABOVE.
SENSIBLE WEATHER HIGHLIGHTS WILL FEATURE SCATTERED SHOWERS AND
ISOLATED THUNDER IN AN ALBEIT ONLY WEAKLY UNSTABLE WARM SECTOR...
PARTICULARLY INVOF THE LEE TROUGH OVER THE PIEDMONT...SAT AFTERNOON
AND NIGHT. SCATTERED TO NUMEROUS SHOWERS AND STORMS AREA-WIDE...
AMIDST AGAIN ONLY WEAK INSTABILITY...ARE THEN FAVORED WITH THE SLOW
PASSAGE OF THE SURFACE COLD FRONT ON SUN. POST-FRONTAL SURFACE HIGH
PRESSURE WILL FOLLOW FOR MON...THOUGH WITH A LINGERING CHANCE OF A
SHOWER OR STORM OVER SE NC...INVOF THE SLOW-MOVING FRONT.
TEMPERATURES WILL TREND FROM THE MIDDLE...TO PERHAPS A FEW UPPER 80S
IN THE COASTAL PLAIN...SAT...TO AROUND SEASONAL AVERAGES AROUND 80
DEGREES ON MON.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 620 AM TUESDAY...
VFR CONDITIONS ARE EXPECTED THROUGH THE 12Z VALID TAF PERIOD. VERY
PATCHY MVFR CLOUDS CONTINUED MAINLY TOWARD KGSB AND A FEW OF THESE
COULD STILL BRIEFLY AFFECT KFAY BEFORE DRIER AIR MOVING IN FROM THE
NORTH RESULTS IN A HIGH PROBABILITY OF VFR CONDITIONS. AS HIGH
PRESSURE BUILDS SOUTH...THE GRADIENT AROUND THE HIGH SHOULD RESULT
IN GUSTY WINDS...WITH SEVERAL GUSTS EXPECTED FROM THE UPPER TEENS TO
LOWER 20S KNOTS BY MID-MORNING THROUGH MID-AFTERNOON BEFORE SOME OF
THE GUSTINESS WANES LATE. 925MB WINDS DIMINISH TO 10 TO 15KT BY 00Z
WEDNESDAY. UNDER VFR CONDITIONS TONIGHT...EAST-NORTHEAST WINDS OFF
OF THE SURFACE COULD INCREASE TO THE UPPER TEENS TO NEAR 25KT BY 03Z
AT THE INVERSION...STRONGEST TOWARD KFAY AND LIGHTEST MORE TOWARD
THE RIDGE AXIS TOWARD KGSO AND KINT.
BEYOND THE 12Z VALID TAF PERIOD...LOCAL MVFR CONDITIONS IN LIGHT FOG
ARE POSSIBLE WEDNESDAY NIGHT...AND DEPENDING ON ANY MID-LEVEL CLOUD
COVER...VERY LOCALLY IFR CONDITIONS COULD OCCUR TOWARD KRWI. SIMILAR
CONDITIONS ARE POSSIBLE DURING THE REST OF THE WORK WEEK. BY
SATURDAY...THERE IS A CHANCE OF SHOWERS AND THUNDERSTORMS AHEAD OF
LOW PRESSURE AND A SURFACE FRONT.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...DJF
SHORT TERM...DJF
LONG TERM...MWS
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1233 PM CDT TUE SEP 17 2013
.UPDATE...
ISSUED AT 1226 PM CDT TUE SEP 17 2013
SOLID SC CLOUD DECK CONTINUES TO OVERSPREAD FA EARLY THIS
AFTERNOON. CLOUDS STILL LOOK FAIRLY SOLID WITH NO BREAKS AT THIS
POINT. BASED ON CURRENT TEMPERATURE TRENDS WILL NEED TO LOWER
MAXIMUM TEMPERATURES SEVERAL DEGREES ACROSS THE BOARD AND STILL
HOPE CIGS BREAK ENOUGH FOR SOME LATE AFTERNOON SOLAR. NO OTHER
CHANGES PLANNED.
UPDATE ISSUED AT 931 AM CDT TUE SEP 17 2013
MADE SOME SLIGHT CLOUD TREND ADJUSTMENTS BASED ON CURRENT
SATELLITE TRENDS OTHERWISE CURRENT FORECAST LOOKING GOOD SO FAR
AND NO OTHER CHANGES MADE.
UPDATE ISSUED AT 656 AM CDT TUE SEP 17 2013
LEADING EDGE OF LOW CLOUDS IS NOW ALONG A COOPERSTOWN TO WAHPETON
LINE AND CONTINUES TO MOVE NORTH-NORTHEAST AROUND 35 MPH. BACK EDGE
OF CLOUD DECK IS A BIT FARTHER WEST THAN PREVIOUS FORECAST...SO
ADJUSTED SKY GRIDS TO REFLECT LATEST OBSERVATIONS. AS A RESULT...
EXPECT ALL BUT THE FAR NORTHWEST FORECAST AREA TO BECOME MOSTLY
CLOUDY BY LATE MORNING INTO THE EARLY AFTERNOON. LATEST HRRR
SUGGESTS THE SUN MAY PEAK OUT FOR A COUPLE HOURS ALONG THE VALLEY
FLOOR BEFORE SUNSET. OTHERWISE...AREAS TO THE EAST WILL REMAIN
CLOUDY FOR MUCH OF THE NIGHT. ALSO DECREASED TEMPERATURES A FEW
DEGREES ACROSS THE NORTHERN VALLEY INTO NORTHWEST MN TO ACCOUNT
FOR MORE EXPANSIVE CLOUDS. REST OF THE FORECAST IN GOOD SHAPE WITH
NO MAJOR CHANGES AT THIS TIME.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 414 AM CDT TUE SEP 17 2013
CHALLENGES INCLUDE CLOUD COVER AND TEMPERATURES TODAY/TONIGHT AND
THEN PRECIPITATION CHANCES/SEVERE POTENTIAL WEDNESDAY NIGHT INTO
THURSDAY. GFS/NAM/ECMWF/GEM IN GOOD OVERALL AGREEMENT AND WILL
USE A BLENDED SOLUTION FOR THIS FORECAST PACKAGE.
FOR TODAY...MOIST SOUTHERLY FLOW BETWEEN THE SURFACE HIGH ACROSS
THE GREAT LAKES AND DEVELOPING LOW IN THE LEE OF THE NORTHERN ROCKIES
WILL ADVECT LOW CLOUDS CURRENTLY ACROSS EASTERN SD/SOUTHERN MN/
NE/IA NORTHWARD ACROSS THE FORECAST AREA. RAP 925 HPA RH SUGGESTS
THESE CLOUDS WILL MOVE INTO THE SOUTHERN FORECAST AREA BY 12 UTC
AND THEN ALONG AND EAST OF THE VALLEY BY THIS AFTERNOON. AREAS
WITH PERSISTENT CLOUD COVER NOT LIKELY TO RISE ABOVE 70 DEGREES.
LOWER TO MID 70S ARE POSSIBLE ACROSS THE DEVILS LAKE BASIN AND
NORTHERN VALLEY WHERE MORE SUNSHINE IS EXPECTED. TODAY WILL ALSO
BE BREEZY TO LOCALLY WINDY WITH 30 KTS IN THE MIXED LAYER. THIS
SHOULD TRANSLATE TO SURFACE WINDS FROM 15 TO 25 MPH WITH GUSTS UP
TO 30 MPH.
LOW CLOUDS WILL BE VERY SLOW TO DISSIPATE OVERNIGHT...ESPECIALLY
ACROSS THE EASTERN FORECAST AREA. MODEL SOUNDINGS SUGGEST THE
POSSIBILITY OF SOME LIGHT DRIZZLE...BUT GIVEN LOW SENSIBLE WEATHER
IMPACT AND COVERAGE UNCERTAINTY...WILL NOT INCLUDE IN CURRENT
GRIDS. SOUTHERLY WINDS WILL REMAIN ELEVATED BETWEEN 10 AND 15
MPH WITH LOW TEMPERATURES GENERALLY IN THE 50S.
STRONG POSITIVE THERMAL ADVECTION IN THE WARM SECTOR OF AN
APPROACHING PACIFIC WAVE WILL RESULT IN TEMPERATURES WELL ABOVE
NORMAL ON WEDNESDAY. AFTERNOON HIGHS WILL CLIMB INTO THE MID 70S
TO LOWER 80S. SOUTHERLY WIND WILL NOT BE AS STRONG AS TODAY. MOST
OF THE DAY SHOULD BE DRY WITH ONLY A CHANCE FOR AFTERNOON SHOWERS
AND THUNDERSTORMS ACROSS THE DEVILS LAKE BASIN.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 414 AM CDT TUE SEP 17 2013
A STRONG SURFACE LOW WILL TRACK ACROSS ND WEDNESDAY EVENING AND
INTO THE CENTRAL/NORTHERN VALLEY BY 06 UTC THURSDAY. WARM
TEMPERATURES ALOFT MAY LIMIT CONVECTIVE INITIATION...BUT THE
COMBINATION OF MLCAPE UP TO 2000 J/KG...PWATS AROUND 1.5 INCHES...
AN APPROACHING SURFACE COLD FRONT AND INCREASING BULK SHEAR FROM A
300 HPA JET STREAK SHOULD RESULT IN THUNDERSTORM DEVELOPMENT
ACROSS EASTERN ND INTO NORTHWEST MN. SOME STORMS NEAREST TO THE
SURFACE LOW MAY BECOME SEVERE AND THIS IS HIGHLIGHTED IN THE SPC
DAY 2 CONVECTIVE OUTLOOK WHICH SHOWS A SLIGHT RISK ALONG AND
NORTHWEST OF A LINE FROM CARRINGTON TO GRAND FORKS TO HALLOCK.
TOO EARLY TO ADD SEVERE WORDING TO THE GRIDS...BUT SOMETHING TO
WATCH.
WITH THE EXCEPTION OF SOME WRAP-AROUND SHOWERS LATE WEDNESDAY
NIGHT INTO THURSDAY ACROSS THE NORTHERN FORECAST AREA...MOST OF
EASTERN ND/NORTHWEST MN WILL BE DRY-SLOTTED ONCE CONVECTION MOVES
INTO CENTRAL AND EAST CENTRAL MN BY 12 UTC THURSDAY. STRONG
WESTERLY WINDS WILL FOLLOW IN THE WAKE OF THE SURFACE FRONT...
ALONG WITH A MUCH COOLER AIR MASS. HIGH TEMPERATURES THURSDAY WILL
RANGE FROM THE LOW 60S ACROSS THE DEVILS LAKE BASIN TO THE LOW 70S
ACROSS WEST CENTRAL MN LAKES COUNTRY. WEST WINDS WILL RANGE FROM
15 TO 25 MPH.
FRIDAY THROUGH MONDAY...THE WEEK WILL END QUIET AND COOL WITH
NORTHWESTERLY FLOW BEHIND THE DEPARTING TROUGH AND HIGH PRESSURE
BUILDING INTO THE PLAINS. A FEW SHOWERS MAY LINGER OVER LAKE OF THE
WOODS AREA BUT OTHERWISE THINK WE WILL BE DRY THROUGH FRIDAY AND
INTO SATURDAY. THE WEEKEND WILL SEE A SLOW WARMING TREND AS
SOUTHERLY WINDS RETURN. THE MAIN UPPER TROUGH WILL REMAIN OVER THE
WESTERN CONUS THROUGH THE END OF THE PERIOD BUT MODELS ALL SHOW
SIGNS OF A LEAD SHORTWAVE MOVING FROM THE NORTHERN ROCKIES THROUGH
THE PLAINS LATE SUNDAY AND INTO MONDAY. KEPT FAIRLY HIGH POPS GOING
FOR SUNDAY NIGHT AND MONDAY AS A WEAK SFC TROUGH AXIS/FRONTAL
BOUNDARY MOVES THROUGH. TEMPS WILL BE A FEW DEGREES LOWER ON MONDAY
BUT STILL AROUND SEASONAL AVERAGES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1226 PM CDT TUE SEP 17 2013
MVFR CIGS EXPECTED TO IMPACT ALL TAF SITES FOR THE REMAINDER OF THE
AFTERNOON AND INTO THE EVENING WITH A SLOW EROSION OF THE STRATUS
DECK FROM WEST TO EAST. GUSTY SOUTHERLY WINDS WILL DIMINISH THIS
EVENING.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...ROGERS
LONG TERM...ROGERS/JR
AVIATION...VOELKER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
933 AM CDT TUE SEP 17 2013
.UPDATE...
ISSUED AT 931 AM CDT TUE SEP 17 2013
MADE SOME SLIGHT CLOUD TREND ADJUSTMENTS BASED ON CURRENT
SATELLITE TRENDS OTHERWISE CURRENT FORECAST LOOKING GOOD SO FAR
AND NO OTHER CHANGES MADE.
UPDATE ISSUED AT 656 AM CDT TUE SEP 17 2013
LEADING EDGE OF LOW CLOUDS IS NOW ALONG A COOPERSTOWN TO WAHPETON
LINE AND CONTINUES TO MOVE NORTH-NORTHEAST AROUND 35 MPH. BACK EDGE
OF CLOUD DECK IS A BIT FARTHER WEST THAN PREVIOUS FORECAST...SO
ADJUSTED SKY GRIDS TO REFLECT LATEST OBSERVATIONS. AS A RESULT...
EXPECT ALL BUT THE FAR NORTHWEST FORECAST AREA TO BECOME MOSTLY
CLOUDY BY LATE MORNING INTO THE EARLY AFTERNOON. LATEST HRRR
SUGGESTS THE SUN MAY PEAK OUT FOR A COUPLE HOURS ALONG THE VALLEY
FLOOR BEFORE SUNSET. OTHERWISE...AREAS TO THE EAST WILL REMAIN
CLOUDY FOR MUCH OF THE NIGHT. ALSO DECREASED TEMPERATURES A FEW
DEGREES ACROSS THE NORTHERN VALLEY INTO NORTHWEST MN TO ACCOUNT
FOR MORE EXPANSIVE CLOUDS. REST OF THE FORECAST IN GOOD SHAPE WITH
NO MAJOR CHANGES AT THIS TIME.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 414 AM CDT TUE SEP 17 2013
CHALLENGES INCLUDE CLOUD COVER AND TEMPERATURES TODAY/TONIGHT AND
THEN PRECIPITATION CHANCES/SEVERE POTENTIAL WEDNESDAY NIGHT INTO
THURSDAY. GFS/NAM/ECMWF/GEM IN GOOD OVERALL AGREEMENT AND WILL
USE A BLENDED SOLUTION FOR THIS FORECAST PACKAGE.
FOR TODAY...MOIST SOUTHERLY FLOW BETWEEN THE SURFACE HIGH ACROSS
THE GREAT LAKES AND DEVELOPING LOW IN THE LEE OF THE NORTHERN ROCKIES
WILL ADVECT LOW CLOUDS CURRENTLY ACROSS EASTERN SD/SOUTHERN MN/
NE/IA NORTHWARD ACROSS THE FORECAST AREA. RAP 925 HPA RH SUGGESTS
THESE CLOUDS WILL MOVE INTO THE SOUTHERN FORECAST AREA BY 12 UTC
AND THEN ALONG AND EAST OF THE VALLEY BY THIS AFTERNOON. AREAS
WITH PERSISTENT CLOUD COVER NOT LIKELY TO RISE ABOVE 70 DEGREES.
LOWER TO MID 70S ARE POSSIBLE ACROSS THE DEVILS LAKE BASIN AND
NORTHERN VALLEY WHERE MORE SUNSHINE IS EXPECTED. TODAY WILL ALSO
BE BREEZY TO LOCALLY WINDY WITH 30 KTS IN THE MIXED LAYER. THIS
SHOULD TRANSLATE TO SURFACE WINDS FROM 15 TO 25 MPH WITH GUSTS UP
TO 30 MPH.
LOW CLOUDS WILL BE VERY SLOW TO DISSIPATE OVERNIGHT...ESPECIALLY
ACROSS THE EASTERN FORECAST AREA. MODEL SOUNDINGS SUGGEST THE
POSSIBILITY OF SOME LIGHT DRIZZLE...BUT GIVEN LOW SENSIBLE WEATHER
IMPACT AND COVERAGE UNCERTAINTY...WILL NOT INCLUDE IN CURRENT
GRIDS. SOUTHERLY WINDS WILL REMAIN ELEVATED BETWEEN 10 AND 15
MPH WITH LOW TEMPERATURES GENERALLY IN THE 50S.
STRONG POSITIVE THERMAL ADVECTION IN THE WARM SECTOR OF AN
APPROACHING PACIFIC WAVE WILL RESULT IN TEMPERATURES WELL ABOVE
NORMAL ON WEDNESDAY. AFTERNOON HIGHS WILL CLIMB INTO THE MID 70S
TO LOWER 80S. SOUTHERLY WIND WILL NOT BE AS STRONG AS TODAY. MOST
OF THE DAY SHOULD BE DRY WITH ONLY A CHANCE FOR AFTERNOON SHOWERS
AND THUNDERSTORMS ACROSS THE DEVILS LAKE BASIN.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 414 AM CDT TUE SEP 17 2013
A STRONG SURFACE LOW WILL TRACK ACROSS ND WEDNESDAY EVENING AND
INTO THE CENTRAL/NORTHERN VALLEY BY 06 UTC THURSDAY. WARM
TEMPERATURES ALOFT MAY LIMIT CONVECTIVE INITIATION...BUT THE
COMBINATION OF MLCAPE UP TO 2000 J/KG...PWATS AROUND 1.5 INCHES...
AN APPROACHING SURFACE COLD FRONT AND INCREASING BULK SHEAR FROM A
300 HPA JET STREAK SHOULD RESULT IN THUNDERSTORM DEVELOPMENT
ACROSS EASTERN ND INTO NORTHWEST MN. SOME STORMS NEAREST TO THE
SURFACE LOW MAY BECOME SEVERE AND THIS IS HIGHLIGHTED IN THE SPC
DAY 2 CONVECTIVE OUTLOOK WHICH SHOWS A SLIGHT RISK ALONG AND
NORTHWEST OF A LINE FROM CARRINGTON TO GRAND FORKS TO HALLOCK.
TOO EARLY TO ADD SEVERE WORDING TO THE GRIDS...BUT SOMETHING TO
WATCH.
WITH THE EXCEPTION OF SOME WRAP-AROUND SHOWERS LATE WEDNESDAY
NIGHT INTO THURSDAY ACROSS THE NORTHERN FORECAST AREA...MOST OF
EASTERN ND/NORTHWEST MN WILL BE DRY-SLOTTED ONCE CONVECTION MOVES
INTO CENTRAL AND EAST CENTRAL MN BY 12 UTC THURSDAY. STRONG
WESTERLY WINDS WILL FOLLOW IN THE WAKE OF THE SURFACE FRONT...
ALONG WITH A MUCH COOLER AIR MASS. HIGH TEMPERATURES THURSDAY WILL
RANGE FROM THE LOW 60S ACROSS THE DEVILS LAKE BASIN TO THE LOW 70S
ACROSS WEST CENTRAL MN LAKES COUNTRY. WEST WINDS WILL RANGE FROM
15 TO 25 MPH.
FRIDAY THROUGH MONDAY...THE WEEK WILL END QUIET AND COOL WITH
NORTHWESTERLY FLOW BEHIND THE DEPARTING TROUGH AND HIGH PRESSURE
BUILDING INTO THE PLAINS. A FEW SHOWERS MAY LINGER OVER LAKE OF THE
WOODS AREA BUT OTHERWISE THINK WE WILL BE DRY THROUGH FRIDAY AND
INTO SATURDAY. THE WEEKEND WILL SEE A SLOW WARMING TREND AS
SOUTHERLY WINDS RETURN. THE MAIN UPPER TROUGH WILL REMAIN OVER THE
WESTERN CONUS THROUGH THE END OF THE PERIOD BUT MODELS ALL SHOW
SIGNS OF A LEAD SHORTWAVE MOVING FROM THE NORTHERN ROCKIES THROUGH
THE PLAINS LATE SUNDAY AND INTO MONDAY. KEPT FAIRLY HIGH POPS GOING
FOR SUNDAY NIGHT AND MONDAY AS A WEAK SFC TROUGH AXIS/FRONTAL
BOUNDARY MOVES THROUGH. TEMPS WILL BE A FEW DEGREES LOWER ON MONDAY
BUT STILL AROUND SEASONAL AVERAGES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 656 AM CDT TUE SEP 17 2013
FRONT EDGE OF MVFR CLOUD DECK NOW EXTENDS FROM KS32 TO KBWP AND IS
MOVING NORTH-NORTHEAST AROUND 30 KTS. ADJUSTED TIMING OF CEILINGS
FOR 12 UTC TAFS BASED ON LATEST OBSERVATIONAL TRENDS. THINK KDVL WILL
BE RIGHT ON THE EDGE OF THE CLOUDS THROUGH THE DAY...SO WILL KEEP
IT SCATTERED FOR NOW. SOUTHERLY WINDS WILL BE ELEVATED THROUGH THE
PERIOD WITH AFTERNOON GUSTS AROUND 25 KTS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...ROGERS
LONG TERM...ROGERS/JR
AVIATION...ROGERS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
656 AM CDT TUE SEP 17 2013
.UPDATE...
ISSUED AT 656 AM CDT TUE SEP 17 2013
LEADING EDGE OF LOW CLOUDS IS NOW ALONG A COOPERSTOWN TO WAHPETON
LINE AND CONTINUES TO MOVE NORTH-NORTHEAST AROUND 35 MPH. BACK EDGE
OF CLOUD DECK IS A BIT FARTHER WEST THAN PREVIOUS FORECAST...SO
ADJUSTED SKY GRIDS TO REFLECT LATEST OBSERVATIONS. AS A RESULT...
EXPECT ALL BUT THE FAR NORTHWEST FORECAST AREA TO BECOME MOSTLY
CLOUDY BY LATE MORNING INTO THE EARLY AFTERNOON. LATEST HRRR
SUGGESTS THE SUN MAY PEAK OUT FOR A COUPLE HOURS ALONG THE VALLEY
FLOOR BEFORE SUNSET. OTHERWISE...AREAS TO THE EAST WILL REMAIN
CLOUDY FOR MUCH OF THE NIGHT. ALSO DECREASED TEMPERATURES A FEW
DEGREES ACROSS THE NORTHERN VALLEY INTO NORTHWEST MN TO ACCOUNT
FOR MORE EXPANSIVE CLOUDS. REST OF THE FORECAST IN GOOD SHAPE WITH
NO MAJOR CHANGES AT THIS TIME.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 414 AM CDT TUE SEP 17 2013
CHALLENGES INCLUDE CLOUD COVER AND TEMPERATURES TODAY/TONIGHT AND
THEN PRECIPITATION CHANCES/SEVERE POTENTIAL WEDNESDAY NIGHT INTO
THURSDAY. GFS/NAM/ECMWF/GEM IN GOOD OVERALL AGREEMENT AND WILL
USE A BLENDED SOLUTION FOR THIS FORECAST PACKAGE.
FOR TODAY...MOIST SOUTHERLY FLOW BETWEEN THE SURFACE HIGH ACROSS
THE GREAT LAKES AND DEVELOPING LOW IN THE LEE OF THE NORTHERN ROCKIES
WILL ADVECT LOW CLOUDS CURRENTLY ACROSS EASTERN SD/SOUTHERN MN/
NE/IA NORTHWARD ACROSS THE FORECAST AREA. RAP 925 HPA RH SUGGESTS
THESE CLOUDS WILL MOVE INTO THE SOUTHERN FORECAST AREA BY 12 UTC
AND THEN ALONG AND EAST OF THE VALLEY BY THIS AFTERNOON. AREAS
WITH PERSISTENT CLOUD COVER NOT LIKELY TO RISE ABOVE 70 DEGREES.
LOWER TO MID 70S ARE POSSIBLE ACROSS THE DEVILS LAKE BASIN AND
NORTHERN VALLEY WHERE MORE SUNSHINE IS EXPECTED. TODAY WILL ALSO
BE BREEZY TO LOCALLY WINDY WITH 30 KTS IN THE MIXED LAYER. THIS
SHOULD TRANSLATE TO SURFACE WINDS FROM 15 TO 25 MPH WITH GUSTS UP
TO 30 MPH.
LOW CLOUDS WILL BE VERY SLOW TO DISSIPATE OVERNIGHT...ESPECIALLY
ACROSS THE EASTERN FORECAST AREA. MODEL SOUNDINGS SUGGEST THE
POSSIBILITY OF SOME LIGHT DRIZZLE...BUT GIVEN LOW SENSIBLE WEATHER
IMPACT AND COVERAGE UNCERTAINTY...WILL NOT INCLUDE IN CURRENT
GRIDS. SOUTHERLY WINDS WILL REMAIN ELEVATED BETWEEN 10 AND 15
MPH WITH LOW TEMPERATURES GENERALLY IN THE 50S.
STRONG POSITIVE THERMAL ADVECTION IN THE WARM SECTOR OF AN
APPROACHING PACIFIC WAVE WILL RESULT IN TEMPERATURES WELL ABOVE
NORMAL ON WEDNESDAY. AFTERNOON HIGHS WILL CLIMB INTO THE MID 70S
TO LOWER 80S. SOUTHERLY WIND WILL NOT BE AS STRONG AS TODAY. MOST
OF THE DAY SHOULD BE DRY WITH ONLY A CHANCE FOR AFTERNOON SHOWERS
AND THUNDERSTORMS ACROSS THE DEVILS LAKE BASIN.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 414 AM CDT TUE SEP 17 2013
A STRONG SURFACE LOW WILL TRACK ACROSS ND WEDNESDAY EVENING AND
INTO THE CENTRAL/NORTHERN VALLEY BY 06 UTC THURSDAY. WARM
TEMPERATURES ALOFT MAY LIMIT CONVECTIVE INITIATION...BUT THE
COMBINATION OF MLCAPE UP TO 2000 J/KG...PWATS AROUND 1.5 INCHES...
AN APPROACHING SURFACE COLD FRONT AND INCREASING BULK SHEAR FROM A
300 HPA JET STREAK SHOULD RESULT IN THUNDERSTORM DEVELOPMENT
ACROSS EASTERN ND INTO NORTHWEST MN. SOME STORMS NEAREST TO THE
SURFACE LOW MAY BECOME SEVERE AND THIS IS HIGHLIGHTED IN THE SPC
DAY 2 CONVECTIVE OUTLOOK WHICH SHOWS A SLIGHT RISK ALONG AND
NORTHWEST OF A LINE FROM CARRINGTON TO GRAND FORKS TO HALLOCK.
TOO EARLY TO ADD SEVERE WORDING TO THE GRIDS...BUT SOMETHING TO
WATCH.
WITH THE EXCEPTION OF SOME WRAP-AROUND SHOWERS LATE WEDNESDAY
NIGHT INTO THURSDAY ACROSS THE NORTHERN FORECAST AREA...MOST OF
EASTERN ND/NORTHWEST MN WILL BE DRY-SLOTTED ONCE CONVECTION MOVES
INTO CENTRAL AND EAST CENTRAL MN BY 12 UTC THURSDAY. STRONG
WESTERLY WINDS WILL FOLLOW IN THE WAKE OF THE SURFACE FRONT...
ALONG WITH A MUCH COOLER AIR MASS. HIGH TEMPERATURES THURSDAY WILL
RANGE FROM THE LOW 60S ACROSS THE DEVILS LAKE BASIN TO THE LOW 70S
ACROSS WEST CENTRAL MN LAKES COUNTRY. WEST WINDS WILL RANGE FROM
15 TO 25 MPH.
FRIDAY THROUGH MONDAY...THE WEEK WILL END QUIET AND COOL WITH
NORTHWESTERLY FLOW BEHIND THE DEPARTING TROUGH AND HIGH PRESSURE
BUILDING INTO THE PLAINS. A FEW SHOWERS MAY LINGER OVER LAKE OF THE
WOODS AREA BUT OTHERWISE THINK WE WILL BE DRY THROUGH FRIDAY AND
INTO SATURDAY. THE WEEKEND WILL SEE A SLOW WARMING TREND AS
SOUTHERLY WINDS RETURN. THE MAIN UPPER TROUGH WILL REMAIN OVER THE
WESTERN CONUS THROUGH THE END OF THE PERIOD BUT MODELS ALL SHOW
SIGNS OF A LEAD SHORTWAVE MOVING FROM THE NORTHERN ROCKIES THROUGH
THE PLAINS LATE SUNDAY AND INTO MONDAY. KEPT FAIRLY HIGH POPS GOING
FOR SUNDAY NIGHT AND MONDAY AS A WEAK SFC TROUGH AXIS/FRONTAL
BOUNDARY MOVES THROUGH. TEMPS WILL BE A FEW DEGREES LOWER ON MONDAY
BUT STILL AROUND SEASONAL AVERAGES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 656 AM CDT TUE SEP 17 2013
FRONT EDGE OF MVFR CLOUD DECK NOW EXTENDS FROM KS32 TO KBWP AND IS
MOVING NORTH-NORTHEAST AROUND 30 KTS. ADJUSTED TIMING OF CEILINGS
FOR 12 UTC TAFS BASED ON LATEST OBSERVATIONAL TRENDS. THINK KDVL WILL
BE RIGHT ON THE EDGE OF THE CLOUDS THROUGH THE DAY...SO WILL KEEP
IT SCATTERED FOR NOW. SOUTHERLY WINDS WILL BE ELEVATED THROUGH THE
PERIOD WITH AFTERNOON GUSTS AROUND 25 KTS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...ROGERS
SHORT TERM...ROGERS
LONG TERM...ROGERS/JR
AVIATION...ROGERS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
414 AM CDT TUE SEP 17 2013
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 414 AM CDT TUE SEP 17 2013
CHALLENGES INCLUDE CLOUD COVER AND TEMPERATURES TODAY/TONIGHT AND
THEN PRECIPITATION CHANCES/SEVERE POTENTIAL WEDNESDAY NIGHT INTO
THURSDAY. GFS/NAM/ECMWF/GEM IN GOOD OVERALL AGREEMENT AND WILL
USE A BLENDED SOLUTION FOR THIS FORECAST PACKAGE.
FOR TODAY...MOIST SOUTHERLY FLOW BETWEEN THE SURFACE HIGH ACROSS
THE GREAT LAKES AND DEVELOPING LOW IN THE LEE OF THE NORTHERN ROCKIES
WILL ADVECT LOW CLOUDS CURRENTLY ACROSS EASTERN SD/SOUTHERN MN/
NE/IA NORTHWARD ACROSS THE FORECAST AREA. RAP 925 HPA RH SUGGESTS
THESE CLOUDS WILL MOVE INTO THE SOUTHERN FORECAST AREA BY 12 UTC
AND THEN ALONG AND EAST OF THE VALLEY BY THIS AFTERNOON. AREAS
WITH PERSISTENT CLOUD COVER NOT LIKELY TO RISE ABOVE 70 DEGREES.
LOWER TO MID 70S ARE POSSIBLE ACROSS THE DEVILS LAKE BASIN AND
NORTHERN VALLEY WHERE MORE SUNSHINE IS EXPECTED. TODAY WILL ALSO
BE BREEZY TO LOCALLY WINDY WITH 30 KTS IN THE MIXED LAYER. THIS
SHOULD TRANSLATE TO SURFACE WINDS FROM 15 TO 25 MPH WITH GUSTS UP
TO 30 MPH.
LOW CLOUDS WILL BE VERY SLOW TO DISSIPATE OVERNIGHT...ESPECIALLY
ACROSS THE EASTERN FORECAST AREA. MODEL SOUNDINGS SUGGEST THE
POSSIBILITY OF SOME LIGHT DRIZZLE...BUT GIVEN LOW SENSIBLE WEATHER
IMPACT AND COVERAGE UNCERTAINTY...WILL NOT INCLUDE IN CURRENT
GRIDS. SOUTHERLY WINDS WILL REMAIN ELEVATED BETWEEN 10 AND 15
MPH WITH LOW TEMPERATURES GENERALLY IN THE 50S.
STRONG POSITIVE THERMAL ADVECTION IN THE WARM SECTOR OF AN
APPROACHING PACIFIC WAVE WILL RESULT IN TEMPERATURES WELL ABOVE
NORMAL ON WEDNESDAY. AFTERNOON HIGHS WILL CLIMB INTO THE MID 70S
TO LOWER 80S. SOUTHERLY WIND WILL NOT BE AS STRONG AS TODAY. MOST
OF THE DAY SHOULD BE DRY WITH ONLY A CHANCE FOR AFTERNOON SHOWERS
AND THUNDERSTORMS ACROSS THE DEVILS LAKE BASIN.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 414 AM CDT TUE SEP 17 2013
A STRONG SURFACE LOW WILL TRACK ACROSS ND WEDNESDAY EVENING AND
INTO THE CENTRAL/NORTHERN VALLEY BY 06 UTC THURSDAY. WARM
TEMPERATURES ALOFT MAY LIMIT CONVECTIVE INITIATION...BUT THE
COMBINATION OF MLCAPE UP TO 2000 J/KG...PWATS AROUND 1.5 INCHES...
AN APPROACHING SURFACE COLD FRONT AND INCREASING BULK SHEAR FROM A
300 HPA JET STREAK SHOULD RESULT IN THUNDERSTORM DEVELOPMENT
ACROSS EASTERN ND INTO NORTHWEST MN. SOME STORMS NEAREST TO THE
SURFACE LOW MAY BECOME SEVERE AND THIS IS HIGHLIGHTED IN THE SPC
DAY 2 CONVECTIVE OUTLOOK WHICH SHOWS A SLIGHT RISK ALONG AND
NORTHWEST OF A LINE FROM CARRINGTON TO GRAND FORKS TO HALLOCK.
TOO EARLY TO ADD SEVERE WORDING TO THE GRIDS...BUT SOMETHING TO
WATCH.
WITH THE EXCEPTION OF SOME WRAP-AROUND SHOWERS LATE WEDNESDAY
NIGHT INTO THURSDAY ACROSS THE NORTHERN FORECAST AREA...MOST OF
EASTERN ND/NORTHWEST MN WILL BE DRY-SLOTTED ONCE CONVECTION MOVES
INTO CENTRAL AND EAST CENTRAL MN BY 12 UTC THURSDAY. STRONG
WESTERLY WINDS WILL FOLLOW IN THE WAKE OF THE SURFACE FRONT...
ALONG WITH A MUCH COOLER AIR MASS. HIGH TEMPERATURES THURSDAY WILL
RANGE FROM THE LOW 60S ACROSS THE DEVILS LAKE BASIN TO THE LOW 70S
ACROSS WEST CENTRAL MN LAKES COUNTRY. WEST WINDS WILL RANGE FROM
15 TO 25 MPH.
FRIDAY THROUGH MONDAY...THE WEEK WILL END QUIET AND COOL WITH
NORTHWESTERLY FLOW BEHIND THE DEPARTING TROUGH AND HIGH PRESSURE
BUILDING INTO THE PLAINS. A FEW SHOWERS MAY LINGER OVER LAKE OF THE
WOODS AREA BUT OTHERWISE THINK WE WILL BE DRY THROUGH FRIDAY AND
INTO SATURDAY. THE WEEKEND WILL SEE A SLOW WARMING TREND AS
SOUTHERLY WINDS RETURN. THE MAIN UPPER TROUGH WILL REMAIN OVER THE
WESTERN CONUS THROUGH THE END OF THE PERIOD BUT MODELS ALL SHOW
SIGNS OF A LEAD SHORTWAVE MOVING FROM THE NORTHERN ROCKIES THROUGH
THE PLAINS LATE SUNDAY AND INTO MONDAY. KEPT FAIRLY HIGH POPS GOING
FOR SUNDAY NIGHT AND MONDAY AS A WEAK SFC TROUGH AXIS/FRONTAL
BOUNDARY MOVES THROUGH. TEMPS WILL BE A FEW DEGREES LOWER ON MONDAY
BUT STILL AROUND SEASONAL AVERAGES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1110 PM CDT MON SEP 16 2013
THE MVFR CLOUDS IN SOUTHERN SD SHOULD SLOWLY ADVECT TO THE NORTH
AND EAST OVERNIGHT. HAVE MENTIONED SOME MVFR CIGS INTO FAR/BJI LATE
TONIGHT INTO TUE MORNING. THESE CLOUDS COULD AFFECT AREAS A BIT
FURTHER NORTH AS WELL...BUT FOR NOW HAVE KEPT ANY CIGS IN THE VFR
RANGE. THERE COULD BE RE-DEVELOPMENT OF CIGS TUE NIGHT AFTER 00Z
WED...AND HAVE MENTIONED THIS AS WELL. WINDS COULD GUST OVER 25KT
IN MOST AREAS BY LATE TUE MORNING AND CONTINUE THROUGH AFTERNOON...
WITH 25-40KT IN THE MIXED LAYER THROUGH TUE MORNING. CAN/T RULE OUT
SOME LOW LEVEL WIND SHEAR LATE TONIGHT IF DE-COUPLING IS STRONGER
THAN FORECAST...WITH 40KT AT TIMES NEAR 925MB IN THE 06-12Z TIME
RANGE. WILL NOT MENTION LLWS IN THE TAF WITH LIMITED CONFIDENCE...BUT
SOMETHING TO KEEP IN MIND.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...ROGERS
LONG TERM...ROGERS/JR
AVIATION...DK
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1025 PM EDT WED SEP 18 2013
.SYNOPSIS...
AN INCREASE IN MOISTURE AND A SERIES OF WEAK UPPER LEVEL
DISTURBANCES WILL RESULT IN A CHANCE OF SHOWERS AND A FEW THUNDERSTORMS
TO THE REGION TONIGHT AND THURSDAY. A BETTER CHANCE OF THUNDERSTORMS
WILL DEVELOP FRIDAY AFTERNOON INTO FRIDAY NIGHT AS A COLD FRONT
MOVES ACROSS THE AREA FROM THE NORTHWEST.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
THERE ARE CONCERNS ON BOTH SIDES OF THE CWA TONIGHT...REQUIRING A
FEW CHANGES TO THE GRIDS.
IN THE EASTERN CWA...A LARGE EXPANSE OF STRATUS HAS DEVELOPED. AS
ADDITIONAL MOISTURE MOVES NORTH INTO THE CWA...THIS IS EXPECTED TO
CONTINUE THROUGH THE NIGHT...WITH CEILINGS LOWERING. SKY GRIDS
HAVE BEEN ADJUSTED...THOUGH IT WAS NOT QUITE POSSIBLE TO INCREASE
TO 100 PERCENT WHEN MOST OF THE CWA STILL IS MOSTLY CLEAR...OR
EVEN BROKEN ON THE EDGES OF THE STRATUS. HOWEVER...THE FAR EASTERN
CWA SHOULD REMAIN CLOUDY THROUGH THE NIGHT.
ATTENTION IS ALSO TURNING TO CONVECTION NEAR CHICAGO...WHICH
SEVERAL RUNS OF THE HRRR AND RAP INDICATE WILL MAKE IT INTO THE
NORTHWEST CWA BY THE EARLY MORNING HOURS. THERE IS A GRADIENT OF
ELEVATED INSTABILITY THAT WILL SHIFT GRADUALLY EAST THROUGH THE
NIGHT...ALLOWING A TRAJECTORY (IF THE CONVECTION HOLDS TOGETHER)
THAT WOULD EVENTUALLY MOVE THROUGH INDIANA AND INTO THE ILN
FORECAST AREA. POPS HAVE BEEN INCREASED IN THE NORTHWESTERN CWA
WITH THUNDER INTRODUCED. TIMING THE CONVECTION OUT WOULD HAVE IT
INTO THE MERCER/WAYNE COUNTY AREAS BY 07Z...AND FURTHER FORECAST
UPDATES WILL BE NECESSARY IF THIS LOOKS MORE LIKELY TO OCCUR.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
ISENTROPIC LIFT DEVELOPS ACROSS THE AREA THURSDAY WITH WARM FRONT
LIFTING NORTHEAST INTO THE GREAT LAKES. WILL CONTINUE CHANCE POPS
WITH THE BEST THREAT ACRS THE NW WHERE MOST FAVORABLE INSTBY WILL
EXIST. IN WARM AIR ADVECTION PATTERN EXPECT TEMPERATURES TO RUN
AROUND 5 DEGREES ABOVE NORMAL...WITH HIGHS RANGING FROM NEAR 80 NE
TO THE MID 80S SW.
WITH THE PASSAGE OF THE WARM FRONT AND RIDGING IN MID LEVELS THERE
WILL BE A LACK OF SIGNIFICANT FORCING THURSDAY NIGHT. HAVE DIMINISHED
POPS FROM THE SOUTH WITH A SLIGHT CHANCE EARLY TO DRY OVERNIGHT.
SRLY SFC WINDS WILL STAY UP AT 5 TO 10 MPH ALONG WITH CLOUD COVER
WILL KEEP TEMPERATURES ON THE WARMER SIDE. EXPECT OVERNIGHT LOWS
TO RANGE FROM THE MID 60S SE TO THE UPPER 60S NW.
PROGRESSIVE/DIGGING MID LEVEL TROF TO MOVE INTO THE WESTERN GREAT
LAKES/UPR MS VLY FRIDAY AND THE GREAT LAKES FRIDAY NIGHT.
ASSOCIATED SFC COLD FRONT TO PUSH EAST THRU ILN/S FA FRIDAY
NIGHT/EARLY SATURDAY. NAM SOLN IS DEPICTING A PRE-FRONTAL TROF
WITH MODERATE INSTBY INTO THE WEST LATE FRIDAY AFTN. GIVEN THE
HIGHER RESOLUTION THIS LOOKS REASONABLE. WILL CONTINUE TO RAMP UP
POPS TO LKLY LATE IN THE DAY FRIDAY AND THEN CATEGORICAL FRIDAY
NIGHT ACRS THE ENTIRE REGION AS THE FRONT PUSHES IN. WILL CONTINUE
TO HIGHLIGHT POTENTIAL FOR LOCALLY DAMAGING WINDS AND SOME HAIL
WITH SOME OF THE STRONGER STORMS FRIDAY AFTN/EARLY EVENING. THIS
WILL BE DEPENDENT ON INSTBY AND WILL LIMIT AREAL EXTENT TO OVER
THE WESTERN COUNTIES. GIVEN WAA AHEAD OF THE FRONT...EXPECT TEMPS
TO BE CLOSE TO 10 DEGREES ABOVE NORMAL WITH HIGHS ON FRIDAY
RANGING FROM THE MID/UPR 80S SE TO THE LOWER 80S FAR NW.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
A COLD FRONT IS EXPECTED TO BE LOCATED THROUGH THE EASTERN PARTS OF
THE FA SATURDAY MORNING. SHOWERS AND SOME THUNDERSTORMS WILL LINGER
BEHIND THE FRONT ON SATURDAY AS THE UPPER TROUGH SWINGS THROUGH THE
OHIO RIVER VALLEY REGION. WIDELY SCATTERED SHOWERS MAY LINGER IN THE
SE ON SUNDAY. LATEST ECMWF IS MORE PROGRESSIVE WITH THE FRONT AND
FUTURE FORECASTS MAY NEED TO CUT BACK ON PRECIPITATION SATURDAY
AFTERNOON AND SUNDAY. ON MONDAY...HIGH PRESSURE WILL BUILD IN FROM
THE NORTH. COULD SEE ENOUGH MOISTURE FROM THE LOW MOVING UP THE
COAST TO PRODUCE ISOLATED SHOWERS IN THE EXTREME EAST. AFTER
MONDAY...SURFACE HIGH PRESSURE EXTENDING INTO THE REGION FROM THE
NE WILL BRING DRY WEATHER AND MILD TEMPERATURES.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
SLIGHTLY UNSETTLED WEATHER CONDITIONS WILL CONTINUE THROUGH THE
NEXT SEVERAL DAYS. MOISTURE CONTINUES TO INCREASE OVER THE OHIO
VALLEY...RESULTING IN INCREASING CLOUDS...AND THE POSSIBILITY FOR
ISOLATED SHOWERS TO DEVELOP AT JUST ABOUT ANY TIME. THIS WILL NOT
BE INCLUDED SPECIFICALLY IN THE TAFS OVERNIGHT...AS THE COVERAGE
WILL BE VERY LOW FOR THE MOST PART.
THE BIGGEST CONCERN OVERNIGHT IS THE POTENTIAL FOR STRATUS
DEVELOPMENT. THERE IS HIGH CONFIDENCE IN A THICKENING OF THE
LOW-LEVEL MOISTURE OVERNIGHT...WITH UPSTREAM CONDITIONS ALREADY
INDICATING MVFR CEILINGS ACROSS MOST OF KENTUCKY. THESE MVFR
CLOUDS ARE EXPECTED TO LOWER INTO THE IFR REGION AS THEY
OVERSPREAD THE TAF SITES. THE FOG FORECAST IS SOMEWHAT
UNCERTAIN...BUT MVFR TO IFR VISIBILITIES ARE EXPECTED...AND THERE
IS SOME POTENTIAL FOR LOWER CONDITIONS THAN THAT.
CEILINGS WILL BE SLOW TO LIFT ON THURSDAY...BUT CONDITIONS WILL
BECOME MORE FAVORABLE FOR SHOWERS AND POSSIBLY
THUNDERSTORMS...MAINLY FOR THE CINCINNATI AND DAYTON TAF SITES.
VCSH HAS BEEN INCLUDED IN THE TAFS FOR THIS TIME FRAME.
OUTLOOK...THUNDERSTORMS WILL BE POSSIBLE FROM FRIDAY AFTERNOON
THROUGH SATURDAY MORNING.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...AR
NEAR TERM...HATZOS
SHORT TERM...AR
LONG TERM...PARKER
AVIATION...HATZOS
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1214 PM CDT TUE SEP 17 2013
.DISCUSSION...
SEE 18Z AVIATION DISCUSSION.
&&
.AVIATION...
RAP AND HRRR KEEP THINGS KIND OF DRY THIS AFTN WITH JUST SOME
SPOTTY SHOWERS EXPECTED OVER THE SOUTHWEST THIRD OF THE REGION AND
OVER THE EXTREME NE PART OF THE AREA. STRONGER WINDS JUST OFF THE
SURFACE ARE MIXING DOWN SO ADDED WIND GUSTS FOR THIS AFTN. MODELS
HINT AT SOME MID LEVEL CLOUDS SCOOTING ACROSS THE AREA OVERNIGHT.
TOMORROW LOOKS SIMILAR TO TODAY WITH SCT CLOUDS BENEATH A CANOPY
OF BKN CIRRUS. 43
&&
.PREV DISCUSSION... /ISSUED 1028 AM CDT TUE SEP 17 2013/
UPDATE...
VERY LITTLE -SHRA ACTIVITY THIS MORNING...ANY MAINLY CONFINED TO
THE COASTAL COUNTIES SURROUNDING MATAGORDA BAY. RIDGING WILL
MAINTAIN GENERAL SUBSIDENCE THROUGH AT LEAST MID-DAY. KLCH
SOUNDING DISPLAYING QUITE A BIT OF MID-LEVEL DRY AIR (1.42 INCH
PW) THAT WILL LIKELY BE ADVECTED OVER THE AREA WITHIN PERSISTENT
EASTERLY FLOW THROUGH THE DAY. ONCE SURFACE TEMPERATURES ACHIEVE
THE UPPER 80S...WIDELY SCATTERED CONVECTIVE ACTIVITY SHOULD BEGIN
TO BLOSSOM FURTHER INLAND. ALL OF THE SHORT TERM HI-REZ PROGS SHOW
NOTHING OF SIGNIFICANCE...POSSIBLE MORE COVERAGE OVER THE FAR NORTH
BUT...WITHIN THIS AIR MASS THERE IS JUST A MODEST CHANCE THAT 20%
OF THE AREA WILL EXPERIENCE MID-LATE AFTERNOON SHOWERS/ISOLATED
STORMS. 17/12Z MID-UPPER LEVEL ANALYSIS VERIFIES RIDGING AT ALL
MANDATORY LEVELS...RIBBON OF HIGHER MID-LAYER MOISTURE OVER
NORTHEASTERN TEXAS (ALSO SEEN ON GOES SOUNDER PWS) MAY AID IN THE
LATE DAY DEVELOPMENT OF NE`ERN CWA -SHRA/-TSRA ACTIVITY. ALL AND
ALL...A QUIET GO OF THINGS GOING INTO MID-WEEK. 31
PREV DISCUSSION... /ISSUED 645 AM CDT TUE SEP 17 2013/
AVIATION...
WITH A SLIGHTLY DRIER AIR MASS MOVING INTO SOUTHEAST TEXAS TODAY...THINK
THE AREA WILL SEE A LITTLE LESS COVERAGE THAT WHAT WAS AROUND DURING
THE AFTERNOON THROUGH EARLY EVENING HOURS ON MONDAY. CARRIED VCSH 20-23Z
FOR IAH AND HOU AND SGR IN THE 12Z TAFS...BUT LATEST TREND IN THE HIGH
RES MODELS POINTS TOWARD VERY LITTLE AFTERNOON THROUGH EARLY EVENING
COVERAGE. THE MAJORITY OF THE AREA TODAY WILL SEE SCT/BKN CIRRUS WITH
SOME LOW LEVEL CU (FEW/SCT) DEVELOPMENT. LIGHT E/NE WINDS THIS MORNING
EXPECTED TO BECOME E/ESE DURING THE MID/LATE MORNING HOURS THEN SE LATE
IN THE AFTERNOON PEAKING AT AROUND 10 KNOTS. LIGHT AND VARIABLE WINDS
TONIGHT THROUGH SUNRISE WEDNESDAY MORNING. 42
PREV DISCUSSION... /ISSUED 404 AM CDT TUE SEP 17 2013/
DISCUSSION...
THE UPPER LEVEL RIDGE IS CENTERED NEARLY OVERHEAD THIS MORNING
WHILE INGRID HAS NOW DISSIPATED INTO A REMNANT LOW ACROSS THE
HIGHER TERRAIN OF MEXICO. SHOWER ACTIVITY OFFSHORE IS LESS THAN
THE PREVIOUS FEW MORNINGS WITH SOME SCATTERED SHOWERS MOVING
INLAND NEAR MATAGORDA BAY AND AN ISOLATED SHOWER OR TWO TRYING TO
FORM NEAR GALVESTON BAY. TODAY LOOKS TO BE A NEAR REPEAT OF
YESTERDAY WITH HIGHS IN THE LOW TO MID 90S AND A FEW SCATTERED
SHOWERS OR THUNDERSTORMS DEVELOPING ACROSS THE SOUTHERN HALF OF
THE REGION.
A TROPICAL WAVE ACROSS THE WESTERN CARIBBEAN SEA WILL PUSH INTO
THE YUCATAN PENINSULA TODAY AND EMERGE OVER THE BAY OF CAMPECHE ON
WEDNESDAY. MODELS KEEP THIS SYSTEM AS A FAIRLY DISORGANIZED AREA
OF LOW PRESSURE THROUGH THE END OF THE WEEK AND ANY MOVEMENT
TOWARD SOUTHEAST TEXAS WILL BE HAMPERED BY AN APPROACHING COLD
FRONT WHICH WILL REACH THE COAST EARLY SATURDAY MORNING. THIS
FRONT IS ASSOCIATED WITH AN UPPER TROUGH CURRENTLY ACROSS THE
PACIFIC NORTHWEST WHICH WILL BUILD INTO THE CENTRAL PLAINS BY THE
END OF THE WEEK. MOISTURE FROM THE REMNANTS OF INGRID AND MANUEL
WILL BE PULLED NORTHWARD INTO TEXAS AHEAD OF THIS SYSTEM AND WILL
ALLOW FOR SHOWERS AND THUNDERSTORMS TO DEVELOP AHEAD OF THE FRONT
ON FRIDAY. HAVE CONTINUED THE TREND OF INCREASING RAIN CHANCES AND
INTRODUCED LIKELY POPS FOR FRIDAY AFTERNOON DUE TO GOOD MODEL
AGREEMENT ON WIDESPREAD COVERAGE. BETTER RAIN CHANCES WILL SHIFT
SOUTHWARD INTO THE COASTAL COUNTIES AND OFFSHORE WATERS ON
SATURDAY AS THE FRONTAL BOUNDARY REACHES THE COAST. THE UPPER
RIDGE WILL REESTABLISH ITSELF ACROSS THE STATE BY EARLY NEXT WEEK
ALLOWING TEMPERATURES TO WARM BACK INTO THE MID 90S. 38
MARINE...
MODERATE EAST WINDS AND ELEVATED SEAS ARE EXPECTED TO PERSIST
THROUGH MID WEEK. A STORM SYSTEM WILL MOVE ACROSS THE SOUTHERN
PLAINS ON FRIDAY...AND THIS SYSTEM WILL DRAG A COLD FRONT ACROSS
THE COASTAL WATERS LATE ON FRIDAY OR EARLY ON SATURDAY. A GOOD
CHANCE OF SHOWERS AND THUNDERSTORMS WILL ACCOMPANY THE FRONTAL
BOUNDARY. 42
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 96 75 96 75 93 / 20 10 20 10 40
HOUSTON (IAH) 94 76 94 76 91 / 20 10 20 20 40
GALVESTON (GLS) 90 81 90 81 89 / 20 20 40 20 40
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 5 PM CDT THIS
AFTERNOON FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO
THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM
HIGH ISLAND TO FREEPORT 20 TO 60 NM.
&&
$$
DISCUSSION...31
AVIATION/MARINE...43
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1113 PM CDT MON SEP 16 2013
.DISCUSSION...
See aviation discussion below...
&&
.AVIATION...
Showers continue near KBBD, and these may persist into the early
morning hours, which is reflected in TAF package. Isolated showers
or thunderstorms will be possible elsewhere overnight, but coverage
should remain isolated enough to preclude a mention in the TAFs.
Patchy stratus may develop at KJCT and KSOA around daybreak, but at
this time I think ceilings will remain VFR. Otherwise, VFR
conditions are expected to prevail with light winds.
&&
.PREV DISCUSSION... /ISSUED 942 PM CDT MON SEP 16 2013/
UPDATE...
Increased POPS sightly across southern sections overnight.
DISCUSSION...
Convection has diminished considerably across the Big Country this
evening with only some light showers remaining. Meanwhile, a new
area of showers and a few thunderstorms are developing across
southeast counties with additional development farther southeast
across the Hill Country. Most of the models are of little help this
evening but the RUC does show an increase in activity along the
I-10 corridor by early morning. Given the latest convective trends,
have increased POPS to 40 percent across the south and will maintain
20 to 30 percent elsewhere for the overnight period. The rest of
the forecast looks on track with no other changes needed at this
time.
PREV DISCUSSION... /ISSUED 613 PM CDT MON SEP 16 2013/
DISCUSSION...
See aviation discussion below...
AVIATION...
Scattered showers and thunderstorms have decreased across much of
West Central Texas during the last hour or so. I still expect
isolated showers and thunderstorms through at least 02z, and this is
reflected in the TAFs. A couple of outflow boundaries are moving
toward KSJT, and this could result in brief gusty variable winds.
Isolated to scattered showers and thunderstorms will be possible on
Tuesday, but I have left any mention out of the TAF package due to
low confidence. Overall, expect VFR conditions to prevail through
the next 24 hours.
PREV DISCUSSION... /ISSUED 409 PM CDT MON SEP 16 2013/
SHORT TERM...
(Tonight and Tuesday)
Upper level high pressure is currently resting across much of Texas
and east into the Gulf of Mexico. This high pressure will be fixed
through Tuesday evening, setting up south southeasterly flow across
the area. This will assist in funneling moisture from Tropical
Storm Ingrid and the remnants of Manuel into West Central Texas.
With this flow pattern we expect the best chances of rainfall across
our southwestern counties. We expect theses showers and
thunderstorms to be diurnally driven, given the lack of capping and
upper level support.
Adjusted the overnight lows into the upper 60s and near 70 to
account for the influx of moisture and expected cloud cover.
Afternoon highs will be near normal with temperatures in the upper
80s to near 90.
18
LONG TERM...
(Tuesday Night through Monday)
Rain Chances Increase with Locally Heavy Rainfall Possible...
The main forecast focus revolves around rain chances Wednesday-
Friday, and the possibility of locally heavy rainfall. There is
also potential for greater coverage of rainfall across our area.
The upper high will shift a bit east and by Wednesday become
centered over the northern Gulf of Mexico. Our area will be on its
western periphery. The 12Z GFS and ECMWF show an upper reflection
from the remnants of Ingrid moving north out of Mexico and into
West Texas on Wednesday, followed by another upper level
disturbance (possible remnants of tropical system near the western
coast of Mexico) moving north- northeast into West Central Texas
by Thursday morning. We have low POPs at this time Wednesday and
Wednesday night, increasing Thursday. These may need to be raised
substantially if subsequent model runs remain consistent. Locally
heavy rainfall will be possible, with precipitable water values
increasing to between 1.5 and 2 inches.
On Friday, an upper trough moving into the Midwest will send a cold
front south into Texas, with the front progged to sag south into
West Central Texas. With a moist airmass remaining in place, could
have additional showers and thunderstorms across our area.
Carrying chance POPs Friday and these also may need to be increased.
Drier conditions are indicated for our area next weekend with upper
shortwave ridge building back into Texas.
19
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 71 89 70 92 71 / 20 20 10 10 10
San Angelo 70 88 69 92 71 / 30 30 10 10 20
Junction 70 87 69 91 70 / 40 30 10 10 20
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
Daniels
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
940 PM CDT WED SEP 18 2013
.UPDATE...
AS THE UPPER TROUGH OVER THE NRN ROCKIES MOVES INTO THE HIGH
PLAINS TNT...THE NOSE OF THE LOW LEVEL JET WILL REFOCUS OVER NE IA
INTO SRN WI THROUGH THU AM. THE 00Z DVN SOUNDING IS VERY MOIST AND
CONDITIONALLY UNSTABLE WITH PWS AT 1.77 INCHES AND ELEVATED CAPE
OF 1561 J/KG WHEN LIFTING A PARCEL FROM 850 MB. NAM FORECAST
SOUNDINGS SHOW SIMILAR THERMODYNAMICS ACROSS SRN WI. THUS NOT
SURPRISED TO SEE THE HRRR MODEL INITIATING A GOOD AMOUNT OF
CONVECTION AFTER 08Z OR 09Z OVER SOUTH CENTRAL WI AND REACHING SE
WI BY SUNRISE. SOME TSTORMS TO BE STRONG WITH HEAVY RAINFALL.
THUNDERSTORMS TO THEN DECREASE IN COVERAGE LATER IN THE MORNING OR
EARLY AFTERNOON THEN INCREASE IN COVERAGE WITH THE COLD FROPA THU
NT. CAPES WILL MAXIMIZE OVER 2000 J/KG THU AFTERNOON WITH 0-3 KM
SRH FROM 150-200 M2/S2 AHEAD OF THE FRONT. DEEP LAYER SHEAR IS
ONLY 20 KTS BUT JUST ENOUGH FOR ORGANIZED SVR STORMS WITH SOME
POTENTIAL FOR SUPERCELLS GIVEN THE AFOREMENTIONED SRH. HEAVY
RAINFALL EXPECTED WITH ANY STORMS GIVEN PWS UP TO 1.8 INCHES.
STORM MOTION AROUND 30 KTS WILL LIMIT FLASH FLOOD POTENTIAL WITH
THE EXCEPTION OF POSSIBLY A HIGH PCPN SUPERCELL.
&&
.AVIATION/06Z TAFS/...
MAINLY VFR CONDITIONS EARLY THU AM BUT SCATTERED TO NUMEROUS
TSTORMS TO DEVELOP AFTER 09Z FOR KMSN AND AFTER 11Z FOR THE SE WI
TAF SITES VIA A LOW LEVEL JET STREAM. TSTORMS TO LAST THROUGH THE
MORNING BEFORE EXITING THE AREA. SOME MVFR CIGS AND VSBYS ARE
POSSIBLE DURING OR AFTER THE TSTORMS BUT SHOULD RETURN TO VFR FOR
THE AFTERNOON. WIDESPREAD TSTORMS THEN EXPECTED LATE THU AFTERNOON
AND EVENING FOR KMSN AND THU NT FOR THE SE WI TAF SITES WITH A
COLD FROPA. REDUCED CIGS AND VSBYS WITHIN STORMS AND MVFR CIGS AND
VSBYS COULD LINGER AFTER THE STORMS...BUT SHOULD BE BRIEF DUE TO
COLD AND DRY AIR ADVECTION AFTER COLD FROPA.
&&
.PREV DISCUSSION... /ISSUED 342 PM CDT WED SEP 18 2013/
TONIGHT AND THURSDAY...FORECAST CONFIDENCE MEDIUM.
SURFACE LOW PRESSURE STRENGTHENING OVER THE DAKOTAS IN RESPONSE TO A
DIGGING UPPER TROUGH WILL TRACK INTO MN OVERNIGHT INTO THURSDAY.
MOISTURE AND WARM AIR WILL CONTINUE TO STREAM NORTHWARD INTO
WISCONSIN AHEAD OF THIS SYSTEM. WITH THESE CONDITIONS OVER SOUTHERN
WI...ANY LITTLE SHORTWAVE COULD KICK UP SOME SCATTERED SHOWERS
ANYWHERE IN SOUTHERN WI. THERE IS UPPER LEVEL INSTABILITY WITH 1000
J/KG OF CAPE TO SUPPORT ISOLATED THUNDER AS WELL. THERE IS A WEAK
SHORTWAVE MOVING ACROSS SOUTHERN WI LATE THIS AFTERNOON...BUT THE
ONLY SHOWERS AS A RESULT OCCURRED IN FAR SOUTHWEST WI AND ARE
WEAKENING. THERE IS ALSO AN MCV MOVING THROUGH NORTHERN IL WHERE
JUST SOME SPRINKLES ARE LEFT TO BRUSH FAR SOUTHERN WI LATE THIS
AFTERNOON.
EXPECTING LULL IN PRECIP CHANCES WITH THE LACK OF SHORTWAVES BETWEEN
00Z AND 06Z. THEN THE LOW LEVEL JET WILL BEGIN TO STRENGTHEN AND
NOSE INTO IOWA AFTER 06Z. THE 18Z NAM AND 00Z ECMWF SHOW A WEAK
SHORTWAVE MOVING INTO SOUTHERN WI LATE TONIGHT. THIS SHOULD RESULT
IN A ROUND OF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS LATE
TONIGHT THROUGH 12Z THU...TAPERING OFF SOUTHWEST TO NORTHEAST
THROUGH MID THU MORNING. THE ECMWF HINTS AT ANOTHER BULLSEYE OF QPF
OVER SOUTH CENTRAL WI THU MORNING...POSSIBLY FROM AN MCV MOVING
NORTHEAST FROM IOWA.
THURSDAY AFTERNOON...CAPE INCREASES TO OVER 2000 J/KG IN SOUTH
CENTRAL WI AND THERE SHOULD BE ENOUGH HEATING AND HIGH DEW POINTS TO
OVERCOME A WEAK CAP AROUND 850MB. WHILE THESE CONDITIONS ARE RIGHT
FOR FUELING SOME STRONGER THUNDERSTORMS...THERE IS STILL A LACK OF A
GOOD TRIGGER AND ALSO SHEAR. HELD POPS IN THE 20 TO 30 PERCENT RANGE
UNTIL LATER IN THE AFTERNOON WHEN A SHORTWAVE OUT AHEAD OF THE MAIN
UPPER TROUGH APPROACHES. HEAVY RAIN WILL BE POSSIBLE IN ANY OF THOSE
AFTERNOON THUNDERSTORMS...AS WELL AS VERY ISOLATED LARGE HAIL AND
DAMAGING WIND.
SHORT TERM...HURSDAY NIGHT THROUGH SATURDAY.
THURSDAY NIGHT AND FRIDAY...FORECAST CONFIDENCE MEDIUM TO HIGH
RAISED POPS TO CATEGORICAL FOR THURSDAY EVENING. MIXED LAYER CAPE
VALUES OF 1500-2000 J/KG THURSDAY EVENING. 0-6KM BULK SHEAR IS 20
KNOTS OR LESS OVER EASTERN CWA...WITH SHEAR VALUES RISING TO AROUND
25 KNOTS IN THE WEST...ENOUGH FOR SOME MULTI-CELL CLUSTERS WITH
STRONG WIND GUST POTENTIAL PER INVERTED V ON MODEL SOUNDINGS. SEVERE
POTENTIAL DROPS OFF INTO THE MID-LATE EVENING AS CONVECTION BECOMES
MORE ELEVATED. HOWEVER PW/S RISE TO BETWEEN 1.70-1.90 INCH...OR
200-220 PCT OF NORMAL...BY THURSDAY EVENING AND DO NOT BEGIN TO DROP
OFF UNTIL AFTER 06Z FRIDAY.
WITH SLOW EASTWARD PROGRESS OF 500 MB TROUGH AS VORTICITY MAXIMA
DEEPEN THE TROUGH...WHICH ALSO SLOWS DEEPENING SURFACE LOW MOVING
ACROSS SOUTHERN ONTARIO AND PROGRESS OF TRAILING COLD FRONT THROUGH
REGION...POTENTIAL IS THERE FOR SOME HIGH EVENT RAIN TOTALS. WHILE
SHOWERS AND STORMS WILL REPEATEDLY DEVELOP WITH PERSISTENT
CONVERGENCE ALONG FRONT...IT WILL BE MOVING WITH INDIVIDUAL CELLS
MOVING AT 10 KNOTS. FLASH FLOOD GUIDANCE IS BETWEEN 2 AND 4 INCHES
AND LOCAL FLASH FLOOD CHECK LIST RESULT IS MARGINAL SO NO WATCH
ANTICIPATED...BUT SOME LOCALIZED PONDING IS POSSIBLE.
WILL TAPER OFF POPS FROM LIKELY IN THE EAST AND CHANCE WEST FRIDAY
MORNING AS 850 AND 500 MB TROUGH AXES PUSH THROUGH AND EXIT THE
REGION BETWEEN 18Z AND 00Z FRIDAY.
LOWS WILL NOT DROP BELOW LOW TO MID 60S THURSDAY NIGHT...WITH LOW TO
MID 70 HIGHS AROUND MIDDAY THEN STEADY OR SLOWLY COOLING WITH COOL
AIR ADVECTION BEHIND FRONT.
FRIDAY NIGHT AND SATURDAY...FORECAST CONFIDENCE HIGH
COOL NIGHT FRIDAY NIGHT WITH HIGH PRESSURE AND 850 MB COLD POCKET
SETTLING INTO REGION. ENOUGH MIXING TO PREVENT FULL RADIATIONAL
COOLING BUT LOWS IN THE 40S EXPECTED AWAY FROM THE LAKE. EXPECT A
BIT OF A SUPER ADIABATIC BUMP FOR SFC HIGHS TOP REACH MID TO UPPER
60S SATURDAY.
LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY. FORECAST CONFIDENCE
MEDIUM TO HIGH
RIDGING BRINGS DRY CONDITIONS WITH SLOWLY WARMING TEMPERATURES
SUNDAY THROUGH MONDAY. ENERGY FROM SHORT WAVE TROUGH EMERGING OUT
INTO THE PLAINS SUNDAY NIGHT AND MONDAY LIFTS NE...WITH
PRECIPITATION DISSIPATING ALONG WEAKENING SURFACE TROUGH AS IT RUNS
INTO HIGH. LATER SHIFTS MAY BE ABLE TO COMPLETELY REMOVE SLIGHT
CHANCE POPS FOR MONDAY NIGHT IF DRY TREND CONTINUES IN LATER RUNS.
PRECIPITATION CHANCES FOR THE REMAINDER OF THE EXTENDED REMAIN WELL
WEST WITH LEE TROUGH OVER THE PLAINS.
AVIATION/00Z TAFS/...
LOOKING FOR POTENTIAL MVFR CIGS AND VSBYS LATE TONIGHT DUE TO DEEPER
MOISTURE STREAMING INTO SOUTHERN WI...ALONG WITH THE CHANCE FOR
SCATTERED SHOWERS AND A FEW THUNDERSTORMS. CONFIDENCE NOT HIGH GIVEN
THE HIGHER WINDS AND POSSIBLE LOW LEVEL MIXING THAT COULD INHIBIT
THE LIGHT FOG AND LOWER CEILINGS.
A PERIOD OF LOW LEVEL WIND SHEAR IS EXPECTED TONIGHT AS THE LOW
LEVEL JET STRENGTHENS OVER THE REGION.
THE BETTER CHANCE FOR STRONG THUNDERSTORMS WITH HEAVY RAIN WILL BE
LATE THURSDAY AFTERNOON AND ALL OF THURSDAY NIGHT AS A COLD FRONT
SLOWLY MOVES WEST TO EAST THROUGH THE UPPER MIDWEST.
MARINE...
A TIGHT PRESSURE GRADIENT OVER LAKE MICHIGAN IN RESPONSE
TO LOW PRESSURE MOVING INTO THE NORTHERN PLAINS WILL CONTINUE TO
BRING GUSTY SOUTH TO SOUTHEAST WINDS...WITH A PROLONGED PERIOD OF 10
TO 20 KNOT WINDS THROUGH THURSDAY AFTERNOON. A FEW WIND GUSTS LIKELY
22-25 KNOTS DURING PEAK HEATING TIMES. BETTER CHANCE FOR HIGHER
WINDS AND RESULTANT WAVES NORTH OF PORT WASHINGTON DUE TO SHORE
ORIENTATION. EXPECTING WAVES TO BUILD TO OVER 4 FEET AT TIMES.
HENCE SMALL CRAFT ADVY IN EFFECT FOR THIS AREA INTO THURSDAY
EVENING. AREAS FARTHER SOUTH WILL NEED TO BE WATCHED CLOSELY BUT NOT
ENOUGH CONFIDENCE IN A PROLONGED PERIOD OF HIGHER WINDS AND WAVES AT
THIS TIME.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 10 PM CDT THURSDAY FOR LMZ643.
&&
$$
UPDATE...GEHRING
TONIGHT/THURSDAY AND AVIATION/MARINE...MRC
THURSDAY NIGHT THROUGH WEDNESDAY...REM
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1139 AM CDT TUE SEP 17 2013
.UPDATE...
LOW LEVEL CLOUDS CONFINED TO THE LAKE RAPIDLY EXPANDED INLAND AS THE
SURFACE INVERSION MIXED OUT. THIS IS BEING FED BY SOUTHEAST WINDS
BRINGING LOW LEVEL MOISTURE INTO EASTERN WI. MADISON WILL EVEN SEE
HINTS OF THESE LOW CLOUDS. EXPECTING THESE CLOUDS TO GRADUALLY
SCATTER OUT DURING THE EARLY AFTERNOON.
MEANWHILE...HIGH CLOUDS WILL CONTINUE TO EXPAND EASTWARD AHEAD OF AN
APPROACHING POTENT SHORTWAVE MOVING THROUGH IOWA THIS MORNING. A
PLUME OF HIGH PRECIPITABLE WATER ACCOMPANIES THIS SHORTWAVE TO
PRODUCE SHOWERS. HRRR BRINGS THE SHOWERS CURRENTLY IN NORTHEAST IOWA
INTO WEST CENTRAL WI AND AVOIDS THE MKX FORECAST AREA. WILL ACCOUNT
FOR A SMALLER AREA OF SHOWERS CURRENTLY IN EASTERN IOWA THAT COULD
SWING UP INTO SOUTH CENTRAL WI LATE THIS AFTERNOON BY INCREASING THE
FORECAST CHANCE POPS A LITTLE EARLIER.
&&
.AVIATION/18Z TAFS/...
MVFR CLOUDS CONFINED TO THE LAKE RAPIDLY EXPANDED INLAND AS THE
SURFACE INVERSION MIXED OUT. THIS IS BEING FED BY SOUTHEAST WINDS
BRINGING LOW LEVEL MOISTURE INTO EASTERN WI. MADISON WILL EVEN SEE
HINTS OF THESE LOW CLOUDS. EXPECTING THESE CLOUDS TO GRADUALLY
SCATTER OUT DURING THE EARLY AFTERNOON.
THEN EXPECT A VFR PERIOD WITH SCT-NMRS -SHRA SPREADING INTO SRN WI
FROM LATE AFTN THRU TNGT. SMALL THREAT FOR T OVER S CENTRAL WI
LATER TNGT INTO WEDNESDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 330 AM CDT TUE SEP 17 2013/
TODAY AND TONIGHT...FORECAST CONFIDENCE...MEDIUM
AREAS OF STRATUS WHICH DEVELOPED OVER THE LAKESHORE COUNTIES AROUND
06Z DUE TO LINGERING HIGH DELTA-T AND INCREASED LOW LEVEL
CONVERGENCE HAVE BECOME MORE PATCHY IN LAST SEVERAL HOURS. LOW
LEVEL WINDS WL CONTINUE TO VEER TO THE SSE THROUGH EARLY MORNING.
WITH DELTA-T REMAINING AROUND 10C...PATCHY STRATUS MAY CONTINUE INTO
THE MORNING AS HIGH CLOUDS INCREASE ACROSS THE AREA.
WATER VAPOR IMAGERY AND WIND PROFILERS INDICATING STRONGER MID-LEVEL
SHORT WAVE VCNTY OF KOMA THAN DEPICTED BY SHORT TERM GUIDANCE. HIGH
PRECIPITABLE WATER VALUES ASSOCIATED WITH THIS WAVE. CURRENTLY
AROUND 0.4 INCHES IN SRN WI. PWAT VALUES TRIPLE RAPIDLY TO AROUND
1.5 INCHES OVER NORTHWEST MO AND WRN IA PER GOES SOUNDER. THIS
DEEPER MOISTURE AND SHORT WAVE MOVES OUR WAY TODAY INTO WRN CWA BY
LATE AFTN AND ACROSS SRN WI TNGT.
305 THETA SURFACE AND LOWER CONDENSATION PRESSURE DEFICITS LINE UP
WELL WITH ONGOING -SHRA OVER WRN IA. THESE LOWER VALUES SPREAD INTO
SOUTHWEST WI LATE AFTN AS SHORT WAVE MOVES INTO THE AREA. HENCE
ADDED SOME POPS TO WRN CWA LATER TODAY AND BEEFED UP POPS SLIGHTLY
THIS EVENING AS MOISTURE AND FORCING ASSOCD WITH SHORT WAVE SPREAD
ACROSS THE AREA. BETTER CHANCE FOR NMRS -SHRA AND ISOLD T LATER
TONIGHT AS DEEPER MOISTURE SETTLES INTO SRN WI AND WEAK LOW LEVEL
JET PIVOTS INTO THE AREA.
WITH STRONG UPSTREAM MOISTURE ADVECTION...THINKING PARTLY SUNNY
SKIES AT BEST TODAY...WITH SOME AREAS LIKELY TURNING MOSTLY CLOUDY.
CLOUDS WILL RETARD HIGH TEMPS A FEW DEGREES...ESPECIALLY WITH SE SFC
WINDS.
WEDNESDAY THROUGH FRIDAY...FORECAST CONFIDENCE...MEDIUM
LOOKS LIKE PRETTY DEEP MOISTURE WEDNESDAY...WITH PRECIPITABLE WATER
VALUES UP TO AROUND 1.75 INCHES. DO THINK THERE WILL BE SOME
ACTIVITY WITH DECENT LOW LEVEL FLOW...WEAK WARM ADVECTION...AND SOME
ELEVATED INSTABILITY. SOUNDINGS LOOK SOMEWHAT CAPPED FOR PART OF THE
DAY AND NOT SEEING A REAL GOOD TRIGGER...SO WENT WITH CHANCE
POPS...NOT DEVIATING MUCH FROM THE PREVIOUS FORECAST. A LOT OF
CLOUDS EXPECTED WEDNESDAY...WITH MODELS STRUGGLING TO MIX TO EVEN
925 MB. THUS KEPT TEMPS A BIT CLOSER TO 2 METER MODEL
VALUES...THOUGH HIGHS WILL STILL BE NEAR TO A COUPLE DEGREES ABOVE
NORMAL.
STRONGEST LOW LEVEL WINDS WILL BE TO THE SOUTHWEST WEDNESDAY
NIGHT...BUT 30-40 KNOT JET DOES POINT INTO THE FORECAST AREA. STILL
WILL BE A GOOD AMOUNT OF MOISTURE WITH INCREASING ELEVATED
INSTABILITY...GETTING AS HIGH AS 1500 J/KG ON NAM SOUNDINGS. WOULD
NOT TAKE MUCH TO KICK OFF MORE SHOWERS/STORMS...SO KEPT CHANCE POPS
GOING.
INSTABILITY IS EXPECTED TO INCREASE EVEN MORE THURSDAY AS A WARM AND
MOIST AIRMASS IS PULLED INTO THE AREA AHEAD OF AN APPROACHING COLD
FRONT. PRECIP CHANCES ARE EXPECTED TO INCREASE AS THE FRONT DRAWS
NEAR...SO WENT WITH LIKELY POPS MAINLY WEST OF MADISON DURING THE
DAY AND THEN ACROSS THE FORECAST AREA IN THE EVENING/OVERNIGHT AS
THE FRONT DRAWS CLOSER OR MOVES THROUGH. LOOKS LIKE A BETTER CHANCE
FOR SOME SUNSHINE AND DEEPER MIXING THAN ON WEDNESDAY. THE AIRMASS
ALOFT WILL BE MILDER AS WELL...SO EXPECTING A WARM DAY INTO THE LOW
80S MOST PLACES.
BUMPED POPS UP A BIT FRIDAY...AS MAIN SHORTWAVE WILL BE MOVING
THROUGH. MODELS HAVE THE SURFACE FRONT RANGING FROM JUST MOVING
INTO THE FORECAST AREA TO JUST THROUGH BY DAYBREAK. STILL A GOOD
AMOUNT OF MOISTURE AND WARM AIR ALOFT AHEAD OF THE SHORTWAVE
THOUGH...SO LOOKS LIKE A DECENT CHANCE FOR LINGERING SHOWERS/STORMS
DURING THE MORNING...MAYBE EVEN HANGING ON IN THE EAST INTO THE
AFTERNOON PER THE SLOWER MODEL SOLUTIONS. COOLER TEMPS ARE LIKELY
FRIDAY...THOUGH HIGHS ARE STILL EXPECTED TO BE NEAR NORMAL VALUES.
SATURDAY THROUGH MONDAY...FORECAST CONFIDENCE...MEDIUM
AFTER A VERY ACTIVE PERIOD...HIGH PRESSURE IS EXPECTED TO SETTLE IN
FOR THE WEEKEND...HANGING ON INTO EARLY NEXT WEEK. SHOULD THUS SEE A
GOOD AMOUNT OF SUNSHINE SATURDAY THROUGH MONDAY WITH SLOWLY WARMING
TEMPERATURES. MAIN ISSUE IS HOW QUICKLY TO WARM THINGS BACK UP...AS
THE GFS KEEPS TEMPS QUITE A BIT COOLER THAN THE ECMWF AND CANADIAN.
GENERALLY SPLIT THE DIFFERENCE IN TEMPS FOR NOW. EITHER WAY...LOOKS
LIKE A PLEASANT STRETCH OF WEATHER.
AVIATION/12Z TAFS/...AREAS OF STRATUS WHICH DEVELOPED OVER THE
LAKESHORE COUNTIES AROUND 05-06Z DUE TO HIGHER DELTA-T AND INCREASED
LOW LEVEL CONVERGENCE HAVE BECOME MORE PATCHY IN LAST HOUR OR SO.
WOULD THINK THIS WILL CONTINUE AS LOW LEVEL WINDS CONTINUE TO VEER
TO THE SSE EARLY THIS MRNG. HOWEVER DELTA-T REMAINS AROUND 10C
THROUGH THE EARLY MORNING SO THREAT FOR LOW CLOUDS WL CONTINUE
THROUGH 15Z OR SO. OTRW EXPECT A VFR PERIOD WITH SCT-NMRS -SHRA
SPREADING INTO SRN WI FROM LATE AFTN THRU TNGT. SMALL THREAT FOR T
OVER S CENTRAL WI LATER TNGT.
MARINE...PRESSURE GRADIENT TIGHTENS OVER LAKE MICHIGAN TODAY AS
HIGH PRESSURE MOVES OFF TO THE EAST AND LOW PRESSURE DEVELOPS IN THE
HIGH PLAINS. WIND SPEEDS WILL INCREASE TO 10 TO 20 KNOTS TODAY AND
PERSIST UNTIL COLD FRONT MOVES THROUGH FRIDAY MORNING. FEW GUSTS MAY
REACH SMALL CRAFT ADVISORY LEVELS DURING THIS TIME BUT NO PROLONGED
PERIOD OF HIGHER GUSTS EXPECTED. WAVES WILL INCREASE TO 2 TO 4 FEET
FOR MUCH OF THE PERIOD AS WELL.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...MRC
TODAY/TONIGHT AND AVIATION/MARINE...MBK
WEDNESDAY THROUGH MONDAY...DDV
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
313 AM MDT THU SEP 19 2013
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 310 AM MDT THU SEP 19 2013
COLD FRONT IS NOW LOCATED ALONG I-70 AND IS EXPECTED TO CONTINUE
DROPPING SEWRD TO NEAR THE SAN JUAN MOUNTAINS BEFORE WASHING OUT.
THE UPPER LEVEL TROUGH IS LAGGING BEHIND THE SFC FRONT AND IS JUST
ENTERING WRN CO AT THIS HOUR. AHEAD OF THE TROUGH...RADAR PICKING
UP SOME RETURNS N OF I-70 WITH A FEW STRAY STORMS ALSO FORMING
THANKS TO UPPER LEVEL SUPPORT AND OROGRAPHIC LIFT. EXPECT THIS TO
CONTINUE THROUGH DAYBREAK WITH SOME MIDLEVEL CLOUDS AROUND THE
AREA FOR THE COMMUTE TO WORK. 00Z NAM12 SHOWED SOME VERY ISOLD
SHOWERS OVER CENT/SRN MTNS THIS AFTERNOON DUE TO LIMITED MOISTURE
AND SOME OROGRAPHICS WHILE 06Z NAM12 HAS ALL BUT REMOVED THEM.
LATEST HRRR AND RAP13 GUIDANCE ALSO SHOWING A DISTINCT LACK OF
PRECIP FOR THE ENTIRE CWA TODAY. NOT SOLD ON IDEA THOUGH AS SOME
MARGINAL INSTABILITY EXISTS ALONG WITH SOME MOISTURE IN LOWER
LEVELS. FOR NOW...WILL LEAVE ISOLD CONVECTION IN FORECAST FOR THE
HIGHEST TERRAIN IN THE SAN JUANS AND CENTRAL MTNS. MOST AREAS
TODAY WILL SEE SUN...SUN...AND MORE SUN AND MORE FALL LIKE
TEMPERATURES AS A PATTERN SHIFT FINALLY SETS UP.
ANY LINGERING SHOWER OR STORM NEAR THE CENTRAL OR SOUTHERN DIVIDE
WILL QUICKLY DIMINISH THIS EVENING WITH SUNSET. WEAK WARM ADVECTION
ALOFT THEN COMMENCES TONIGHT AS A PROGRESSIVE UPPER RIDGE
APPROACHES...BUT IT WILL NOT LIKELY BE ENOUGH TO OFFSET RADIATIONAL
COOLING DUE TO CLEAR SKIES AND DRIER AIR. HENCE...A COOL NIGHT LOOKS
IN STORE WITH POCKETS OF FREEZING OR NEAR FREEZING TEMPS TO THE
LOWER VALLEYS IN THE CRAIG AND MEEKER AREAS AND WILL CONTINUE THE
FREEZE WATCH FOR THESE AREAS TONIGHT. MODELS SUGGEST THAT THE
STEAMBOAT VALLEY AND AROUND GUNNISON WILL BOTTOM OUT IN THE MID 30S.
TEMPS SHOULD WARM QUICKLY FRIDAY MORNING WITH PLENTY OF SUNSHINE.
DRY AND SUNNY CONDITIONS ARE EXPECTED FRIDAY WITH HIGH TEMPS
REBOUNDING AS THE UPPER RIDGE SLIDES ACROSS THE AREA. AFTERNOON
HUMIDITIES WILL DROP INTO THE TEENS FRIDAY AFTERNOON IN MANY OF THE
NORTHWEST AND WEST-CENTRAL COLORADO VALLEYS...AND EASTERN UTAH
VALLEYS.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 310 AM MDT THU SEP 19 2013
FLOW ALOFT BECOMES SOUTHWEST FRIDAY NIGHT AND SATURDAY AS THE UPPER
RIDGE MOVES TO THE EAST AND A PACIFIC TROUGH PUSHES INLAND. GRADIENT
TIGHTENS SATURDAY AS THE TROUGH ADVANCES FOR STRENGTHENING AND GUSTY
SURFACE WINDS ACROSS NE UT/NW CO SATURDAY AFTERNOON...AND TEMPS
SHOULD WARM OVER FRIDAY. NAM MODEL SHOWS MID-LEVEL MOISTURE BEING
DRAWN NORTHWARD INTO SW CO AS EARLY AS FRI NIGHT WHILE THE GFS WAITS
UNTIL SAT. THE EVENING MODELS ALSO DID SEEM QUITE AS ENTHUSIASTIC
WITH RAISING PRECIPITABLE WATER VALUES AS EARLIER RUNS. STILL...MAY
SEE A FEW SHOWERS OR THUNDERSTORMS OVER THE SAN JUANS SAT AFTERNOON
AND MADE LITTLE CHANGE TO THE CURRENT FORECAST FOR THE FIRST HALF OF
THE WEEKEND.
BIG DIFFERENCE IN LONG-TERM FOR THE WEEKEND AS PREVIOUS GFS RUNS
SHOWED MARGINAL PRECIP WITH AN APPROACHING TROUGH AND SFC COLD
FRONT WHILE LATEST RUN SHOWS SIGNIFICANT PRECIP FOR MUCH OF THE
AREA SUNDAY AFTERNOON AND NIGHT. EC ALSO SHOWING THIS PRECIP WHILE
NAM12 SHOWING VERY LITTLE AT THIS TIME. MOISTURE TRANSPORT VECTORS
ON THE 320K SURFACE DO SHOW SOME MOISTURE STREAMING UP FROM THE
SOUTH SATURDAY NIGHT INTO SUNDAY MORNING BEFORE BEING WORKED ON BY
THE TROUGH. THE TROUGH WILL BE SUPPORTED BY AN 80 KT JET STREAK
AND IT LOOKS LIKE THIS TROUGH MAY BECOME NEGATIVELY TILTED. IF YOU
PUT ALL OF THESE TOGETHER...SOME WIDESPREAD PRECIP CAN BE EXPECTED
WITH SOME STRONG THUNDERSTORMS POSSIBLE. CAN ALSO EXPECT SOME
GUSTY SFC WINDS...ESPECIALLY SUNDAY...AHEAD OF SAID FRONT. SOME
WHITE STUFF ALSO POSSIBLE AT THE HIGHEST ELEVATIONS...ABOVE 13K
FT...AS H7 TEMPS DROP TO AROUND 3C. SFC TEMPERATURES WILL DROP 8
TO 10 DEGREES FROM SATURDAY TO SUNDAY AS THE COLD FRONT PUSHES
THROUGH.
BY MONDAY MORNING...THE TROUGH AND FRONT WILL HAVE EXITED OUR AREA
ALLOWING ZONAL FLOW TO SET UP BRINGING A PERIOD OF DRY WEATHER AND
SEASONAL TEMPERATURES THROUGH WEDNESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 310 AM MDT THU SEP 19 2013
VFR CONDITIONS ARE PREDOMINANT AT THIS HOUR AND THESE CONDITIONS
WILL CONTINUE FOR THE NEXT 24 HOURS. A SLIGHT CHANCE EXISTS FOR
SOME CONVECTION TO FIRE OVER THE HIGHER ELEVATIONS OF THE SAN
JUANS AND CENTRAL MOUNTAINS BUT NO EFFECTS TO TAF SITES EXPECTED.
SOME MOUNTAIN OBSCURATIONS WILL CONTINUE THROUGH DAYBREAK TODAY.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR COZ002.
UT...NONE.
&&
$$
SHORT TERM...TGR/JAD
LONG TERM...JAD/TGR
AVIATION...TGR
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
315 AM CDT THU SEP 19 2013
.DISCUSSION...
336 PM CDT
MAIN CHALLENGES/CONCERNS THIS FORECAST PERIOD ARE WITH SHOWERS AND
THUNDERSTORMS IN THE NEAR TERM...POSSIBLE PERSISTENT
SHOWERS/THUNDERSTORMS OVERNIGHT...AS WELL AS BETTER CHANCES FOR
SHOWERS/THUNDERSTORMS THURSDAY NIGHT INTO FRIDAY MORNING.
CONTINUE TO MONITOR AREA OF SHOWERS AND THUNDERSTORMS ACROSS NORTH
CENTRAL ILLINOIS THAT HAVE CONTINUED TO SLOWLY MOVE EAST TODAY.
LATEST RADAR IMAGERY DEPICTING A CONTINUED DEVELOPING TREND IN
BOTH COVERAGE AND INTENSITY WITH THIS AREA OF PRECIPITATION...AND
EXPECT THIS TO CONTINUE THROUGH THE AFTERNOON AND EARLY EVENING.
MCV IS THE MAIN DRIVING FORCE FOR THESE
SHOWERS/THUNDERSTORMS...WITH LATEST RAP ANALYSIS SHOWING LOWERING
CIN AND AN AXIS OF 1000 J/KG OF SB CAPE EXTENDING INTO NORTHEAST
ILLINOIS AND NORTHWEST INDIANA. ALTHOUGH NOT THE GREATEST...THESE
CONDITIONS WILL BE ENOUGH TO HELP THIS PRECIP TO HOLD TOGETHER
WHILE IT SLOWLY MOVES THROUGH NORTHEAST ILLINOIS THIS AFTERNOON
AND THEN NORTHWEST INDIANA THROUGH EARLY EVENING. ALTHOUGH
WIDESPREAD SEVERE WEATHER IS NOT ANTICIPATED...A PORTION OF THESE
STORMS ALONG THE I-80 CORRIDOR HAVE EXHIBITED SOME STRENGTHENING
TRENDS WITH BRIEF HIGHER WIND SIGNATURES. SO FOR THIS
AFTERNOON/EARLY EVENING...EXPECT ANY OF THE STRONGER STORMS IN
THIS GENERAL AREA TO BE CAPABLE OF PRODUCING SPORADIC WIND GUSTS
TO 50 MPH...CONTINUOUS LIGHTNING...AND BRIEF HEAVY RAINFALL WITH
AN OUTSIDE POSSIBILITY OF AN ISOLATED SEVERE WIND THREAT.
WITH THE DEPARTURE OF THESE THUNDERSTORMS...MOST OF THE CWA SHOULD
OBSERVE A LULL IN PRECIP BEFORE SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE ONCE AGAIN OVER NIGHT. SEVERAL WEAK MID LEVEL FEATURES
WILL CONTINUE TO TRAVERSE CURRENT ZONAL FLOW OVERHEAD...WITH
LOW/MID LEVEL FLOW VEERING OVERNIGHT. AS THIS OCCURS...IT APPEARS
AS BETTER WAA WILL ORIENT ITSELF MORE TOWARDS NORTHERN ILLINOIS.
ALTHOUGH CONFIDENCE IS NOT THE GREATEST FOR COVERAGE TONIGHT...DID
MAINTAIN LOW CHANCE POPS FOR MOST AREAS MAINLY AFTER MIDNIGHT
OWING TO THIS POTENTIAL. WHATEVER DOES DEVELOP SHOULD BE MORE
SCATTERED IN NATURE...AND THEN BEGIN SHIFTING EAST OUT OF THE CWA
WHILE DIMINISHING EARLY THURSDAY MORNING. WITH BROAD SOUTHWESTERLY
FLOW PERSISTING ON THURSDAY AND A FAIRLY MOIST ENVIRONMENT
OVERHEAD...SHOWERS AND THUNDERSTORMS WILL REMAIN POSSIBLE.
ALTHOUGH...CHANCES FOR PRECIPITATION SHOULD REMAIN LOW WITH ONCE
AGAIN ANYTHING THAT DOES DEVELOP REMAINING SCATTERED. WITH THIS
PERSISTENT WAA...CONTINUED WARMUP WILL CONTINUE ON THURSDAY. MADE
LITTLE ADJUSTMENTS TO MAX TEMPS FOR THURSDAY KEEPING UPPER 80S FOR
MOST LOCATIONS...WITH SOME UNCERTAINTIES TO PRECIP AND EVEN CLOUD
COVER REMAINING. IF ENOUGH CLEARING OCCURS...THERMO PROFILES WILL
BE SUPPORTIVE OF SOME LOCATIONS REACHING OR SLIGHTLY EXCEEDING 90
DEGREES.
MAIN FOCUS FOR THUNDERSTORM DEVELOPMENT SHIFTS TOWARDS THE LATE
AFTERNOON AND EARLY EVENING WITH AN APPROACHING TROUGH OF LOW
PRESSURE AND COLD FRONT. AS LARGE VORT MAX DROPS SOUTHEAST ACROSS
THE NORTHERN PLAINS...SEVERAL WAVES OF ENERGY WILL LIFT NORTHEAST
ACROSS THE REGION. THIS WILL HELP TO SHIFT THIS TROUGH/FRONT AS WELL
AS INDUCING SOME FURTHER PRESSURE FALLS OUT AHEAD OF IT. WITH
POTENTIAL FOR PRE FRONTAL TROUGHINESS TO OCCUR TOMORROW
AFTERNOON...SOME GUIDANCE CONTINUES TO DEVELOP PRECIP OUT AHEAD OF
THIS FRONT. ALTHOUGH I FEEL THIS IS A BIT OVERDONE...AND HAVE HELD
BACK ON POPS FOR THURSDAY DURING THE DAY. HAVE EVEN TRENDED
TOWARDS A SLOWER SOLUTION/TREND WITH THIS FRONT/TROUGH WITH BEST
CHANCES FOR SHOWERS/THUNDERSTORMS REMAINING OVER WEST/NORTHWEST
ILLINOIS FOR MOST OF THURSDAY NIGHT. ITS NOT UNTIL EARLY FRIDAY
MORNING THAT THIS FRONT GETS A GOOD SOUTHEAST PUSH WITH BEST
FORCING MOVING OVERHEAD. GOOD SWATH OF PRECIP SHOULD SHIFT
SOUTHEAST ACROSS THE ENTIRE CWA THROUGH MID DAY FRIDAY...WITH THIS
PRECIP THEN EXPECTED TO SHIFT OUT OF THE AREA THROUGH THE
AFTERNOON. IT DOES APPEAR AS IF THE STRONGER STORMS SHOULD REMAIN
JUST WEST OF THE CWA...BUT WITH SOME POTENTIAL FOR THEM TO REACH
THE FAR WESTERN CWA THURSDAY EVENING/NIGHT. IF INSTABILITY CAN
INCREASE ON FRIDAY...THERE IS THE POTENTIAL FOR A LINGERING STRONG
TO SEVERE THREAT ACROSS THE CWA BEFORE THE STORMS SHIFT OUT OF THE
CWA.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* LOW CHANCE FOR ADDITIONAL SHRA/TSRA DURG THE MORNING HOURS.
* ANOTHER ROUND OF SHRA/TSRA POSSIBLE LATE THURSDAY NIGHT WITH
COLD FRONT PASSAGE.
* SLY TO SSWLY WINDS GUSTING TO ARND 20KT LATE MORNING THROUGH
EARLY EVENING.
KREIN
//DISCUSSION...UPDATED 06Z...
TWO PRIMARY CONCERNS THROUGH THE PERIOD WILL BE CHANCES FOR
ADDITIONAL SHRA/TSRA AND SLY-SSWLY WINDS GUSTING IN THE LOW 20S KT.
THE REGION REMAINS UNDER WARM/MOIST ADVECTION WITH SLY FLOW AT THE
SFC AND SWLY FLOW THROUGH THE LOWEST 10KFT ABOVE THE SFC LAYER.
WHILE THE STRONGEST WARM ADVECTION AND ISENTROPIC LIFT REMAINS TO
THE WEST...OVER THE UPPER MISSOURI VALLEY TO THE MIDDLE
MISSISSIPPI VALLEY...THERE WILL STILL BE ENOUGH FORCING TO KEEP A
CHANCE OF SHRA/TSRA IN THE TAFS. CONFIDENCE IS LOW AS TO THE
TIMING AND COVERAGE OF PCPN THIS MORNING...SO WILL KEEP THE TEMPO
GROUP IN THE FORECAST. LATEST RADAR IMAGERY ONLY INDICATES SOME
ISOLD ECHOES OVER NRN IL/IN...ASIDE FROM THE ONGOING CONVECTION
OVER NWRN INDIANA...EAST OF GYY. BUT GIVEN THE MOIST
ENVIRONMENT...WILL LEAVE THE TEMPO IN THE FORECAST FOR A LITTLE
LONGER AS THERE IS A CHANCE FOR INCREASED DEVELOPMENT THROUGH THE
MORNING HOURS. WHILE THERE MAY STILL BE LOW CHANCES FOR ADDITIONAL
SHRA/TSRA THROUGH THE AFTERNOON AND INTO EARLY
EVENING...CONFIDENCE IN TIMING AND COVERAGE IS EVEN LOWER...SO
WILL KEEP THE FORECAST DRY THROUGH THIS EVENING.
THE NEXT...MORE SIGNIFICANT CHANCE FOR SHRA/TSRA WILL COME
OVERNIGHT THURSDAY NIGHT AS A STRONG COLD FRONT APPROACHES THE
REGION. THE CONVECTIVE ACTIVITY SHOULD LARGELY BE INVOF THE
FRONT...WHICH SHOULD MOVE INTO NWRN IL BY LATE THIS EVENING AND
THEN REACH THE CHICAGO AREA TERMINALS. CONFIDENCE IS A LITTLE
HIGHER WITH THIS SYSTEM...SO HAVE ADDED A TEMPO GROUP THE END OF
THE RFD TAF...AND A PROB30 GROUP TO THE 30-HR EXTENDED PERIOD OF
THE ORD TAF. AS TIMING OF THE FRONTAL PASSAGE BECOMES A BIT MORE
CERTAIN...WILL LIKELY NEED TO CARRY A PREVAILING GROUP TSRA.
FOR WINDS...THERE IS LITTLE CHANGE TO THE GOING FORECAST. WINDS
SHOULD REMAIN SLY THROUGH THE NIGHT AT ARND 10KT. THERE IS A
CHANCE FOR SOME HIGHER GUSTINESS IF ADDITIONAL PCPN DOES DEVELOP.
WITH DAYTIME WARMING AND SOME BREAKING UP OF CLOUD COVER...HIGHER
GUSTS SHOULD MIX DOWN TO THE SFC AND FREQUENT GUSTS TO ARND 20KT
SHOULD PREVAIL FROM LATE MORNING THROUGH EARLY EVENING. AS THE
FRONTAL TROUGH APPROACHES THE MISSISSIPPI RIVER LATER TODAY...WIND
DIRECTION SHOULD VEER A LITTLE WEST OF SOUTH TO 200-210 DEGREES
BEFORE QUICKLY SHIFTING TO NWLY WITH THE FROPA.
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* LOW CONFIDENCE ON SHRA/TSRA THROUGH LATE THIS MORNING.
* MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS.
* MEDIUM TO HIGH CONFIDENCE IN ADDITIONAL SHRA/TSRA LATE THURSDAY
NIGHT INTO FRIDAY MORNING WITH THE FROPA...BUT LOWER CONFIDENCE
IN EXACT TIMING.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...SHRA/TSRA LIKELY THROUGH LATE AFTERNOON...SHRA POSSIBLY
LINGERING INTO THE EVENING. MVFR POSSIBLE. WIND SHIFT FROM SWLY TO
NWLY IN THE AFTERNOON.
SATURDAY THROUGH TUESDAY...VFR. WX NIL.
KJB
&&
.MARINE...
300 AM CDT
AN AREA OF LOW PRESSURE CENTERED OVER THE EASTERN DAKOTAS WILL
WEAKEN SLIGHTLY AND TRACK NORTHEAST TO WESTERN ONTARIO BY THIS
EVENING. SOUTHERLY WINDS TO AROUND 25 KT WILL PERSIST OVER THE
LAKE AS THE THE LOW DEEPEN FURTHER AND TRACKS NORTHEAST INTO
NORTHERN QUEBEC BY SATURDAY MORNING. AN ASSOCIATED COLD FRONT WILL
SWEEP ACROSS LAKE MICHIGAN FRIDAY AFTERNOON AND EVENING...WITH
WINDS GRADUALLY VEERING FROM SOUTHWESTERLY TO NORTHWESTERLY
AND...ULTIMATELY NORTHEASTERLY...AS A LARGE AREA OF HIGH PRESSURE
BUILDS IN BEHIND THE FRONT. IN THE COLD ADVECTION BEHIND THE
FRONT...NORTHWEST TO NORTH WINDS WILL REDEVELOP...WITH SOME
OCCASIONAL GUSTS TO 30KT POSSIBLE FRIDAY NIGHT.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1250 AM CDT THU SEP 19 2013
.DISCUSSION...
336 PM CDT
MAIN CHALLENGES/CONCERNS THIS FORECAST PERIOD ARE WITH SHOWERS AND
THUNDERSTORMS IN THE NEAR TERM...POSSIBLE PERSISTENT
SHOWERS/THUNDERSTORMS OVERNIGHT...AS WELL AS BETTER CHANCES FOR
SHOWERS/THUNDERSTORMS THURSDAY NIGHT INTO FRIDAY MORNING.
CONTINUE TO MONITOR AREA OF SHOWERS AND THUNDERSTORMS ACROSS NORTH
CENTRAL ILLINOIS THAT HAVE CONTINUED TO SLOWLY MOVE EAST TODAY.
LATEST RADAR IMAGERY DEPICTING A CONTINUED DEVELOPING TREND IN
BOTH COVERAGE AND INTENSITY WITH THIS AREA OF PRECIPITATION...AND
EXPECT THIS TO CONTINUE THROUGH THE AFTERNOON AND EARLY EVENING.
MCV IS THE MAIN DRIVING FORCE FOR THESE
SHOWERS/THUNDERSTORMS...WITH LATEST RAP ANALYSIS SHOWING LOWERING
CIN AND AN AXIS OF 1000 J/KG OF SB CAPE EXTENDING INTO NORTHEAST
ILLINOIS AND NORTHWEST INDIANA. ALTHOUGH NOT THE GREATEST...THESE
CONDITIONS WILL BE ENOUGH TO HELP THIS PRECIP TO HOLD TOGETHER
WHILE IT SLOWLY MOVES THROUGH NORTHEAST ILLINOIS THIS AFTERNOON
AND THEN NORTHWEST INDIANA THROUGH EARLY EVENING. ALTHOUGH
WIDESPREAD SEVERE WEATHER IS NOT ANTICIPATED...A PORTION OF THESE
STORMS ALONG THE I-80 CORRIDOR HAVE EXHIBITED SOME STRENGTHENING
TRENDS WITH BRIEF HIGHER WIND SIGNATURES. SO FOR THIS
AFTERNOON/EARLY EVENING...EXPECT ANY OF THE STRONGER STORMS IN
THIS GENERAL AREA TO BE CAPABLE OF PRODUCING SPORADIC WIND GUSTS
TO 50 MPH...CONTINUOUS LIGHTNING...AND BRIEF HEAVY RAINFALL WITH
AN OUTSIDE POSSIBILITY OF AN ISOLATED SEVERE WIND THREAT.
WITH THE DEPARTURE OF THESE THUNDERSTORMS...MOST OF THE CWA SHOULD
OBSERVE A LULL IN PRECIP BEFORE SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE ONCE AGAIN OVER NIGHT. SEVERAL WEAK MID LEVEL FEATURES
WILL CONTINUE TO TRAVERSE CURRENT ZONAL FLOW OVERHEAD...WITH
LOW/MID LEVEL FLOW VEERING OVERNIGHT. AS THIS OCCURS...IT APPEARS
AS BETTER WAA WILL ORIENT ITSELF MORE TOWARDS NORTHERN ILLINOIS.
ALTHOUGH CONFIDENCE IS NOT THE GREATEST FOR COVERAGE TONIGHT...DID
MAINTAIN LOW CHANCE POPS FOR MOST AREAS MAINLY AFTER MIDNIGHT
OWING TO THIS POTENTIAL. WHATEVER DOES DEVELOP SHOULD BE MORE
SCATTERED IN NATURE...AND THEN BEGIN SHIFTING EAST OUT OF THE CWA
WHILE DIMINISHING EARLY THURSDAY MORNING. WITH BROAD SOUTHWESTERLY
FLOW PERSISTING ON THURSDAY AND A FAIRLY MOIST ENVIRONMENT
OVERHEAD...SHOWERS AND THUNDERSTORMS WILL REMAIN POSSIBLE.
ALTHOUGH...CHANCES FOR PRECIPITATION SHOULD REMAIN LOW WITH ONCE
AGAIN ANYTHING THAT DOES DEVELOP REMAINING SCATTERED. WITH THIS
PERSISTENT WAA...CONTINUED WARMUP WILL CONTINUE ON THURSDAY. MADE
LITTLE ADJUSTMENTS TO MAX TEMPS FOR THURSDAY KEEPING UPPER 80S FOR
MOST LOCATIONS...WITH SOME UNCERTAINTIES TO PRECIP AND EVEN CLOUD
COVER REMAINING. IF ENOUGH CLEARING OCCURS...THERMO PROFILES WILL
BE SUPPORTIVE OF SOME LOCATIONS REACHING OR SLIGHTLY EXCEEDING 90
DEGREES.
MAIN FOCUS FOR THUNDERSTORM DEVELOPMENT SHIFTS TOWARDS THE LATE
AFTERNOON AND EARLY EVENING WITH AN APPROACHING TROUGH OF LOW
PRESSURE AND COLD FRONT. AS LARGE VORT MAX DROPS SOUTHEAST ACROSS
THE NORTHERN PLAINS...SEVERAL WAVES OF ENERGY WILL LIFT NORTHEAST
ACROSS THE REGION. THIS WILL HELP TO SHIFT THIS TROUGH/FRONT AS WELL
AS INDUCING SOME FURTHER PRESSURE FALLS OUT AHEAD OF IT. WITH
POTENTIAL FOR PRE FRONTAL TROUGHINESS TO OCCUR TOMORROW
AFTERNOON...SOME GUIDANCE CONTINUES TO DEVELOP PRECIP OUT AHEAD OF
THIS FRONT. ALTHOUGH I FEEL THIS IS A BIT OVERDONE...AND HAVE HELD
BACK ON POPS FOR THURSDAY DURING THE DAY. HAVE EVEN TRENDED
TOWARDS A SLOWER SOLUTION/TREND WITH THIS FRONT/TROUGH WITH BEST
CHANCES FOR SHOWERS/THUNDERSTORMS REMAINING OVER WEST/NORTHWEST
ILLINOIS FOR MOST OF THURSDAY NIGHT. ITS NOT UNTIL EARLY FRIDAY
MORNING THAT THIS FRONT GETS A GOOD SOUTHEAST PUSH WITH BEST
FORCING MOVING OVERHEAD. GOOD SWATH OF PRECIP SHOULD SHIFT
SOUTHEAST ACROSS THE ENTIRE CWA THROUGH MID DAY FRIDAY...WITH THIS
PRECIP THEN EXPECTED TO SHIFT OUT OF THE AREA THROUGH THE
AFTERNOON. IT DOES APPEAR AS IF THE STRONGER STORMS SHOULD REMAIN
JUST WEST OF THE CWA...BUT WITH SOME POTENTIAL FOR THEM TO REACH
THE FAR WESTERN CWA THURSDAY EVENING/NIGHT. IF INSTABILITY CAN
INCREASE ON FRIDAY...THERE IS THE POTENTIAL FOR A LINGERING STRONG
TO SEVERE THREAT ACROSS THE CWA BEFORE THE STORMS SHIFT OUT OF THE
CWA.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* LOW CHANCE FOR ADDITIONAL SHRA/TSRA DURG THE MORNING HOURS.
* ANOTHER ROUND OF SHRA/TSRA POSSIBLE LATE THURSDAY NIGHT WITH
COLD FRONT PASSAGE.
* SLY TO SSWLY WINDS GUSTING TO ARND 20KT LATE MORNING THROUGH
EARLY EVENING.
KREIN
//DISCUSSION...UPDATED 06Z...
TWO PRIMARY CONCERNS THROUGH THE PERIOD WILL BE CHANCES FOR
ADDITIONAL SHRA/TSRA AND SLY-SSWLY WINDS GUSTING IN THE LOW 20S KT.
THE REGION REMAINS UNDER WARM/MOIST ADVECTION WITH SLY FLOW AT THE
SFC AND SWLY FLOW THROUGH THE LOWEST 10KFT ABOVE THE SFC LAYER.
WHILE THE STRONGEST WARM ADVECTION AND ISENTROPIC LIFT REMAINS TO
THE WEST...OVER THE UPPER MISSOURI VALLEY TO THE MIDDLE
MISSISSIPPI VALLEY...THERE WILL STILL BE ENOUGH FORCING TO KEEP A
CHANCE OF SHRA/TSRA IN THE TAFS. CONFIDENCE IS LOW AS TO THE
TIMING AND COVERAGE OF PCPN THIS MORNING...SO WILL KEEP THE TEMPO
GROUP IN THE FORECAST. LATEST RADAR IMAGERY ONLY INDICATES SOME
ISOLD ECHOES OVER NRN IL/IN...ASIDE FROM THE ONGOING CONVECTION
OVER NWRN INDIANA...EAST OF GYY. BUT GIVEN THE MOIST
ENVIRONMENT...WILL LEAVE THE TEMPO IN THE FORECAST FOR A LITTLE
LONGER AS THERE IS A CHANCE FOR INCREASED DEVELOPMENT THROUGH THE
MORNING HOURS. WHILE THERE MAY STILL BE LOW CHANCES FOR ADDITIONAL
SHRA/TSRA THROUGH THE AFTERNOON AND INTO EARLY
EVENING...CONFIDENCE IN TIMING AND COVERAGE IS EVEN LOWER...SO
WILL KEEP THE FORECAST DRY THROUGH THIS EVENING.
THE NEXT...MORE SIGNIFICANT CHANCE FOR SHRA/TSRA WILL COME
OVERNIGHT THURSDAY NIGHT AS A STRONG COLD FRONT APPROACHES THE
REGION. THE CONVECTIVE ACTIVITY SHOULD LARGELY BE INVOF THE
FRONT...WHICH SHOULD MOVE INTO NWRN IL BY LATE THIS EVENING AND
THEN REACH THE CHICAGO AREA TERMINALS. CONFIDENCE IS A LITTLE
HIGHER WITH THIS SYSTEM...SO HAVE ADDED A TEMPO GROUP THE END OF
THE RFD TAF...AND A PROB30 GROUP TO THE 30-HR EXTENDED PERIOD OF
THE ORD TAF. AS TIMING OF THE FRONTAL PASSAGE BECOMES A BIT MORE
CERTAIN...WILL LIKELY NEED TO CARRY A PREVAILING GROUP TSRA.
FOR WINDS...THERE IS LITTLE CHANGE TO THE GOING FORECAST. WINDS
SHOULD REMAIN SLY THROUGH THE NIGHT AT ARND 10KT. THERE IS A
CHANCE FOR SOME HIGHER GUSTINESS IF ADDITIONAL PCPN DOES DEVELOP.
WITH DAYTIME WARMING AND SOME BREAKING UP OF CLOUD COVER...HIGHER
GUSTS SHOULD MIX DOWN TO THE SFC AND FREQUENT GUSTS TO ARND 20KT
SHOULD PREVAIL FROM LATE MORNING THROUGH EARLY EVENING. AS THE
FRONTAL TROUGH APPROACHES THE MISSISSIPPI RIVER LATER TODAY...WIND
DIRECTION SHOULD VEER A LITTLE WEST OF SOUTH TO 200-210 DEGREES
BEFORE QUICKLY SHIFTING TO NWLY WITH THE FROPA.
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* LOW CONFIDENCE ON SHRA/TSRA THROUGH LATE THIS MORNING.
* MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS.
* MEDIUM TO HIGH CONFIDENCE IN ADDITIONAL SHRA/TSRA LATE THURSDAY
NIGHT INTO FRIDAY MORNING WITH THE FROPA...BUT LOWER CONFIDENCE
IN EXACT TIMING.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...SHRA/TSRA LIKELY THROUGH LATE AFTERNOON...SHRA POSSIBLY
LINGERING INTO THE EVENING. MVFR POSSIBLE. WIND SHIFT FROM SWLY TO
NWLY IN THE AFTERNOON.
SATURDAY THROUGH TUESDAY...VFR. WX NIL.
KJB
&&
.MARINE...
256 PM CDT
AN AREA OF LOW PRESSURE CENTERED OVER THE DAKOTAS IS TO WEAKEN
SLIGHTLY AS IT TRACKS NORTHEAST TO SOUTHERN CANADA BY MIDDAY
THURSDAY. THE LOW THEN DEEPENS FRIDAY AND MOVES ACROSS JAMES BAY.
AN ASSOCIATED COLD FRONT WILL MOVE SOUTHEASTWARD AND ACROSS LAKE
MI DURING FRIDAY SHIFTING SOUTH AND SOUTHWESTERLY WINDS TO OUT OF
THE WEST AND NORTHWEST AND INCREASING TO STRONG BREEZES. AS LARGE
HIGH PRESSURE BUILDS SOUTHEASTWARD ACROSS THE WESTERN GREAT LAKES
FRIDAY THROUGH SUNDAY WINDS WILL GRADUALLY RELAX AS THEY VEER
THROUGH NORTH AND EAST TO SOUTHEAST.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
459 AM EDT THU SEP 19 2013
.SYNOPSIS...
ISSUED AT 454 AM EDT THU SEP 19 2013
MOISTURE WILL CONTINUE TO INCREASE ACROSS THE AREA TODAY...MAKING
IT FEEL MUCH MORE HUMID AND IT WILL BE WARMER AS WELL. A COUPLE OF
WEAK UPPER LEVEL DISTURBANCES WILL COMBINE WITH THE MOISTURE TO
PRODUCE A CHANCE OF SHOWERS AND THUNDERSTORMS TODAY AND TONIGHT. A
BETTER CHANCE OF SHOWERS AND THUNDERSTORMS IS EXPECTED ON FRIDAY
AS A STRONG COLD FRONT MOVES THROUGH. TEMPERATURES WILL COOL BACK
BELOW NORMAL FOR THE WEEKEND.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 454 AM EDT THU SEP 19 2013
MESOSCALE CONVECTIVE VORTEX...MCV...WHICH MOVED OUT OF IA
YESTERDAY AND INTO IL LAST EVENING HAS BEEN SLOWLY MOVING ACROSS
NORTHERN INDIANA EARLY THIS MORNING. THIS FEATURE INTERACTED WITH
THETA E RIDGE ADVECTING ACROSS THE REGION ALONG WITH PRECIPITABLE
WATER VALUES OVER 1.5 INCHES. THE RESULT WAS SLOW MOVING
THUNDERSTORMS WITH SOME TRAINING OVER WESTERN AREAS. DUAL POL
RADAR ESTIMATES OF BETWEEN 2 AND 5 INCHES OF RAIN IN SOUTHWEST
PULASKI AND WHITE COUNTIES PROMPTED ISSUANCE OF FLASH FLOOD
WARNING AS FFG WAS AROUND 3 INCHES. RADAR SHOWING THIS PCPN
FINALLY COMING TO AN END. HOWEVER...ANOTHER LINE OF TSRA HAS
DEVELOPED ON LEADING EDGE OF SECONDARY THETA E MAX WITH LOW LEVEL
JET ADDING CONVERGENCE AND THIS LINE IS MOVING EAST. HAVE INCLUDED
SCATTERED TO NUMEROUS THUNDERSTORMS THROUGH DAYBREAK TO ACCOUNT
FOR BOTH AREAS OF PRECIPITATION. SHOULD SEE ALL ACTIVITY END/MOVE
OUT OF THE AREA SHORTLY AFTER DAYBREAK.
REMAINDER OF DAY IN FLUX AS SUBSIDENCE FROM DEPARTING MCV SHOULD
STABILIZE LOWER LEVELS. HOWEVER...BREAKS IN CLOUDS TO DEVELOP WITH
PARTLY CLOUDY EXPECTED AGAIN TODAY. 925-850MB TEMPS WARM A FEW
DEGREES FROM YESTERDAY AND HIGHS EXPECTED TO CLIMB WELL INTO 80S.
MODEST INSTABILITY DEVELOPS THIS AFTERNOON WITH PEAK HEATING AND
MOISTURE RICH AIR AS SFC DEW POINTS CLIMB INTO UPPER 60S. NAM12
SHOWING MUCAPES OVER 3000 J/KG BUT LIKELY OVERDONE GIVEN ITS
DEWPOINTS INTO LOWER 70S. HAVE TRENDED POPS DOWN TO SLIGHT CHANCE
MID MORNING INTO EARLY AFTERNOON WITH A TREND BACK UP TO LOW CHANCE
THIS AFTERNOON WITH ANY DEVELOPMENT WITH PEAK HEATING.
MODELS CONTINUE TO BE RATHER AGGRESSIVE WITH CONVECTIVE DEVELOPMENT
TONIGHT WELL AHEAD OF MAIN COLD FRONT. KEPT SIMILAR TREND OF
INCREASING POPS THROUGH THE NIGHT AS FRONT NEARS. LOCALIZED HEAVY
RAINFALL STILL POSSIBLE THROUGH THE SHORT TERM PERIOD GIVEN HIGH
PWATS AND THETA E AIR ALONG WITH TRAINING POTENTIAL.
&&
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 454 AM EDT THU SEP 19 2013
A COLD FRONT WILL BE MOVING SOUTHEAST INTO THE AREA FRIDAY.
GFS/ECMWF TELECONNECTIONS SUPPORT THE TROF STARTING TO BECOME
POSITIVELY TILTED BY LATE SATURDAY. CONCERNS FRIDAY AND FRIDAY NIGHT
FOR THUNDERSTORMS WITH HEAVY RAIN GIVEN THE LIKELIHOOD OF
BACKBUILDING CELLS. GFS BUFKIT FOR SEVERAL RUNS CONTINUES TO SHOW
MEAN CLOUD LAYER WINDS COMBINED WITH A LOW LEVEL JET FAVORING LITTLE
NET CELL MOVEMENT. ALSO FAVORING HEAVY RAIN IS THAT THE WARM CLOUD
LAYER WILL LIKELY BE GENERALLY OVER 11K FEET DEEP WITH PRECIPITABLE
WATER VALUES BETWEEN 1.7 TO 1.9 INCHES. THIS IS AROUND 2 STANDARD
DEVIATIONS AND APPROACHING THE 99TH PERCENTILE PER UPPER AIR CLIMATE
DATA. ALSO...CAPES SHOULD GENERALLY BE UNDER 1000 J/KG. THE SEVERE
WEATHER POTENTIAL LOOKS MORE MARGINAL FRIDAY GIVEN LIMITED/SKINNY
CAPES AND WEAK/STABLE MID LEVEL LAPSE RATES. HOWEVER...UPPER LEVEL
DYNAMICS INCLUDING THE TRANSLATION OF THE RIGHT ENTRANCE OF A 100+
KNOT JET SHOULD HELP TO STRENGTHEN STORMS. USED THE ECMWF/GFS TO
PUT SOME DETAIL IN THE TIMING OF THE SHOWERS AND STORMS FRIDAY.
ALSO...RAISED RAINFALL AMOUNTS GIVEN THE ABOVE REASONING.
OTHERWISE...LINGERING SHOWERS SHOULD END EARLY SATURDAY FOLLOWED BY
DRY CONDITIONS THE REST OF THE PERIOD. TRIED TO BLEND TEMPERATURES
TOWARD THE GFS OPERATIONAL RUN MEX WHICH APPEARS ON TRACK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 454 AM EDT THU SEP 19 2013
A DIFFICULT AVIATION FORECAST THIS PERIOD WITH MESOSCALE
CONVECTIVE SYSTEM OVER THE AREA AND HEADING TOWARD KFWA. MODEL
GUIDANCE STRUGGLING WITH THIS FEATURE BUT HIRES HRRR HAS A
REASONABLE HANDLE ON MOVEMENT. EXPECT SHOWERS INTO KFWA AROUND 06Z
WITH OCCASIONAL THUNDER FOR A FEW HOURS. RADAR SHOWS A TRAILING
CONVECTIVE LINE PARALLEL TO MEAN FLOW AND SHEAR VECTOR OVER
NORTHWEST INDIANA. THIS IS SLOWLY DRIFTING EAST WHILE ALSO SHOWING
SIGNS OF WEAKENING. MEANWHILE...NEW DEVELOPMENT OCCURRING OVER
LAKE MICHIGAN. HAVE INCLUDED A VCTS AT KSBN STARTING AROUND 08Z
FOR THIS ACTIVITY AND WILL MONITOR MOVEMENT FOR POSSIBLE UPDATE.
OTHERWISE SATELLITE SHOWING MID LEVEL CLOUD DECK DEVELOPING
UPSTREAM IN WARM AND MOIST SOUTHERLY FLOW. CLOUD COVER AGAIN A
PROBLEM FOR TODAY BUT EXPECT MAINLY VFR CIGS AFTER DAYBREAK WITH
AN OUTSIDE CHANCE OF SOME MVFR CIGS AFTER RAIN ENDS BEFORE
SUNRISE. CONFIDENCE LOW IN CONVECTIVE DEVELOPMENT TODAY. MOIST LOW
LEVELS BUT NO STRONG TRIGGER AND MODELS ALL OVER THE PLACE. HAVE
OPTED TO LEAVE OUT OF TAFS GIVEN UNCERTAINTY IN COVERAGE BUT A LOW
CHANCE WILL EXIST THROUGH THE PERIOD AND INTO FRIDAY WHEN STRONG
COLD FRONT ARRIVES.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...LASHLEY
SHORT TERM...LASHLEY
LONG TERM...SKIPPER
AVIATION...LASHLEY
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AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
146 AM EDT THU SEP 19 2013
.SYNOPSIS...
ISSUED AT 800 PM EDT WED SEP 18 2013
INCREASED MOISTURE WILL CONTINUE TO LIFT NORTHEAST INTO THE AREA
THROUGH THURSDAY. A COUPLE OF WEAK UPPER LEVEL DISTURBANCES WILL
COMBINE WITH THIS MOISTURE TO PRODUCE A CHANCE OF SHOWERS AND
THUNDERSTORMS TONIGHT THROUGH THURSDAY NIGHT. A BETTER CHANCE OF
SHOWERS AND THUNDERSTORMS IS EXPECTED ON FRIDAY AS A STRONGER
UPPER LEVEL SYSTEM SHIFTS INTO THE UPPER MIDWEST ALLOWING A COLD
FRONT TO APPROACH FRIDAY AFTERNOON AND EVENING. WARMER CONDITIONS
CAN BE EXPECTED THURSDAY IN ADVANCE OF THE FRONT...COOLING BACK
BELOW NORMAL FOR THE WEEKEND.
&&
.UPDATE...
ISSUED AT 800 PM EDT WED SEP 18 2013
A FAIRLY COMPACT MCV HAS ALLOWED FOR SCATTERED SHOWERS AND
THUNDERSTORMS TO BE MAINTAINED INTO NORTHWEST INDIANA THIS
EVENING. THE STRONGEST OF THESE CELLS EARLY THIS EVENING IS
LOCATED ON THE SOUTHERN PERIPHERY OF THE MCV ACROSS JASPER COUNTY
IN NORTHWEST INDIANA...BUT SHOULD GRADUALLY WEAKEN AS IT MOVES OFF
PRIMARY 500-1000 J/KG MUCAPE AXIS OVER NEXT FEW HOURS. POTENTIAL
OF SURFACE BASED INSTABILITY ALSO SHOULD WANE DURING THIS TIME
FRAME...ALTHOUGH MARGINAL CAPES ON THE ORDER OF 500 J/KG FOR
SLIGHTLY ELEVATED PARCELS SHOULD PERSIST. SCATTERED THUNDERSTORMS
HAVE ALSO DEVELOPED ON NORTHERN EDGE OF MCV ACROSS NORTHEAST
ILLINOIS...BUT CONFIDENCE REMAINS LOW THAT THESE THUNDERSTORMS
WILL SURVIVE INTO WESTERN PORTIONS OF THE AREA TOWARD MIDNIGHT. SHORT
TERM GUIDANCE IS IN FAIRLY GOOD AGREEMENT IN SECONDARY LOW LEVEL
THETAE SURGE WORKING INTO ESPECIALLY NORTHERN LOCATIONS OVERNIGHT
AS WEAK SHORT WAVE ACROSS NORTHERN IOWA TOPS THE UPPER LEVEL RIDGE
IN PLACE. THIS COULD RESULT IN ADDITIONAL ELEVATED CONVECTION
OVERNIGHT WHICH IS ALREADY COVERED IN INHERITED FORECAST WITH
SLIGHT CHANCE POPS ACROSS NORTHERN TWO THIRDS OF THE AREA. ONLY
TWEAK TO PREVIOUS FORECAST WAS TO INCREASE POPS ACROSS THE WEST
THIS EVENING TO ACCOUNT FOR MCV EVOLUTION.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 350 PM EDT WED SEP 18 2013
LEE CYCLOGENESIS IS NOW WELL UNDERWAY ACROSS THE NORTHERN PLAINS AS
MODERATE AMPLITUDE PV ANOMALY LIFTS OUT OF THE NORTHERN ROCKIES.
WITH A PERSISTENT SURFACE HIGH ACROSS THE EAST COAST...THIS HAS
OPENED THE DOOR FOR SOUTHWEST FLOW AND BROAD THETA-E ADVECTION
LOCALLY. VERY LITTLE FOCUS FOR SUSTAINED UVM IN THE WAKE OF THIS
MORNING`S SHORTWAVE PASSAGE THOUGH. LINGERING EFFECTS OF VERY DRY
CANADIAN AIRMASS ARE STILL BEING FELT WITH LITTLE MORE THAN AN
ISOLATED SPRINKLE ACROSS THE AREA EARLIER TODAY. CONVECTIVE LINE
ACROSS NORTHERN ILLINOIS IS EXPECTED TO DISSIPATE AS IT INTERSECTS
THIS VERY DRY AND STABLE AIRMASS LATER THIS EVENING BUT A FEW
DECAYING SHOWERS MAY BE POSSIBLE IN OUR WEST AS SUGGESTED BY SOME
PREVIOUS RUNS OF THE HRRR. THE CHANCES OF RAIN WILL THEN INCREASE
AGAIN BY LATE TONIGHT AND INTO TOMORROW BUT THE FORCING WILL
REMAIN RATHER WEAK AND BROAD. PRECIP CHANCES WILL LARGELY DEPEND
ON NOCTURNAL STRENGTHENING OF THE LLJ DRAPED ACROSS THE MIDWEST.
THOUGH THE BEST MOISTURE CONVERGENCE WILL INITIALLY BE FOCUSED
NORTHWEST OF OUR CWA...SLIGHT VEERING IS EXPECTED BY EARLY
TOMORROW MORNING WITH ANOTHER SURGE OF INCREASING
WAA/FRONTOGENESIS ACROSS OUR NORTHWEST COUNTIES. 305K SYSTEM
RELATIVE ISENTROPIC ASCENT IS NOT OVERLY IMPRESSIVE AND THERE WILL
BE A LIMITED TIME WINDOW BEFORE THE LLJ WEAKENS LATER THURSDAY
MORNING BUT SHOULD BE ENOUGH FORCING AND AVAILABLE MOISTURE TO
SUPPORT A FEW SCATTERED SHOWERS AND PERHAPS AN ISOLATED RUMBLE OF
THUNDER...MAINLY IN OUR NORTHWEST. INCREASING WAA AND ASSOCIATED
CLOUD COVER WILL ALSO LEAD TO MILD OVERNIGHT LOWS WITH VALUES
LIKELY NOT DROPPING MUCH BELOW THE LOW TO MID 60S.
SOUTHERN GREAT LAKES WILL BE FIRMLY IN THE WARM SECTOR TOMORROW.
850MB TEMPS CLIMB INTO THE UPPER TEENS...YIELDING AFTERNOON HIGHS IN
THE LOW TO MID 80S DESPITE A FAIR AMOUNT OF CLOUD COVER. CONTINUED
MOISTURE ADVECTION WILL ALSO PUSH SURFACE DEWPOINTS INTO THE MID TO
UPPER 60S...RAISING THE PROSPECTS FOR SURFACE BASED CONVECTION.
APPROACHING TROUGH AND OVERALL MODEST NATURE OF DOWNSTREAM RIDGE
RESULTS IN VERY LITTLE CAP AS WELL. FORCING WILL BE RATHER
ILL-DEFINED BUT MODEST INSTABILITY IN A REGION OF BROAD WARM/MOIST
AIR ADVECTION SHOULD SUPPORT AT LEAST SCATTERED SHOWERS AND
THUNDERSTORMS BY THE AFTERNOON. NO SEVERE WEATHER EXPECTED GIVEN
ONLY ABOUT 1500 J/KG OF SBCAPE AND 15-20 KTS DEEP LAYER SHEAR.
&&
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 350 PM EDT WED SEP 18 2013
STRONG UPR LEVEL TROF OVER THE NRN ROCKIES THIS AFTN IS EXPECTED TO
MOVE EAST TO THE UPR MS VALLEY THU NGT AND ACROSS THE GRTLKS FRI-FRI
NGT. AS THIS SYSTEM APPROACHES... MOISTURE AND LIFT SHOULD GRDLY
INCREASE FROM NW-SE ACROSS THE CWA THU NGT CAUSING SCT
SHOWERS/TSTMS. MODEST S-SW SFC GRADIENT WINDS WILL PERSIST THROUGH
THE NGT RESULTING IN MILD LOW TEMPS IN THE U60S. SFC CDFNT
ASSOCIATED WITH THIS TROF IS EXPECTED MOVE FROM NW-SE ACROSS OUR CWA
FRI AFTN-NGT WITH RAIN CHANCES PEAKING DURING THIS TIMEFRAME. GIVEN
GOOD INTRA MODEL AND RUN-RUN CONTINUITY IN THIS REGARD... HAVE
TRENDED POPS UP FRI. MODELS SUGGEST MODERATE SFC BASED INSTABILITY
WILL DVLP IN OUR AREA FRI AS STRENGTHENING 0-6KM SHEAR ASSOCIATED
WITH THE UPR TROF MOVES IN FROM THE NW. STILL APPEARS TO BE JUST A
SMALL CHC INGREDIENTS NEEDED FOR SEVERE STORMS WILL COME TOGETHER
OVER OUR AREA... WITH BULK OF STRONG SHEAR STILL FCST TO LAG
BEST INSTABILITY. LOCALLY HEAVY RAINFALL REMAINS A POSSIBILITY
FRI/FRI EVE AS PROGGED SMALL MBE VECTORS... VERY MOIST AIRMASS...
AND DEEP WARM CLOUD LAYER SUGGEST EFFICIENT RAINFALL PROCESS IN
CONVECTION WITH POTENTIAL FOR SOME TRAINING/BACKBUILDING CELLS...
THOUGH GIVEN DRY ANTECEDENT MOISTURE CONDITIONS ACROSS MOST OF OUR
CWA... EXPECT ANY FLOODING WILL BE LOCALIZED. LEANED TOWARD WARMER
MOS GUIDANCE FOR HIGHS FRIDAY AS GOOD GRADIENT MIXING OF WARM
AIRMASS EXPECTED DURING DRY PERIODS.
HIGH PRESSURE RIDGE WILL BUILD INTO THE AREA SATURDAY BRINGING ANY
LINGERING SHOWERS ERN PORTION OF CWA TO AN END EARLY WITH CAA
RESULTING IN TEMPS A BIT BLO NORMAL. THIS RIDGE IS EXPECTED TO
LINGER OVER THE WRN GRTLKS INTO THE MIDDLE OF NEXT WEEK AS ANOTHER
STRONG TROF DIGS INTO THE WRN U.S. AND A CUT-OFF LOW FORMS OVER THE
SERN U.S. AND THEN LIFTS NEWD UP THE ERN SEABOARD. THIS SHOULD
RESULT IN A PROLONGED PERIOD OF DRY WX WITH TEMPS MODERATING TO A
LITTLE ABOVE NORMAL EARLY-MIDDLE NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 145 AM EDT THU SEP 19 2013
A DIFFICULT AVIATION FORECAST THIS PERIOD WITH MESOSCALE
CONVECTIVE SYSTEM OVER THE AREA AND HEADING TOWARD KFWA. MODEL
GUIDANCE STRUGGLING WITH THIS FEATURE BUT HIRES HRRR HAS A
REASONABLE HANDLE ON MOVEMENT. EXPECT SHOWERS INTO KFWA AROUND 06Z
WITH OCCASIONAL THUNDER FOR A FEW HOURS. RADAR SHOWS A TRAILING
CONVECTIVE LINE PARALLEL TO MEAN FLOW AND SHEAR VECTOR OVER
NORTHWEST INDIANA. THIS IS SLOWLY DRIFTING EAST WHILE ALSO SHOWING
SIGNS OF WEAKENING. MEANWHILE...NEW DEVELOPMENT OCCURRING OVER
LAKE MICHIGAN. HAVE INCLUDED A VCTS AT KSBN STARTING AROUND 08Z
FOR THIS ACTIVITY AND WILL MONITOR MOVEMENT FOR POSSIBLE UPDATE.
OTHERWISE SATELLITE SHOWING MID LEVEL CLOUD DECK DEVELOPING
UPSTREAM IN WARM AND MOIST SOUTHERLY FLOW. CLOUD COVER AGAIN A
PROBLEM FOR TODAY BUT EXPECT MAINLY VFR CIGS AFTER DAYBREAK WITH
AN OUTSIDE CHANCE OF SOME MVFR CIGS AFTER RAIN ENDS BEFORE
SUNRISE. CONFIDENCE LOW IN CONVECTIVE DEVELOPMENT TODAY IN WAKE OF
MCV. MOIST LOW LEVELS BUT NO STRONG TRIGGER AND MODELS ALL OVER
THE PLACE. HAVE OPTED TO LEAVE OUT OF TAFS GIVEN UNCERTAINTY IN
COVERAGE BUT A LOW CHANCE WILL EXIST THROUGH THE PERIOD AND INTO
FRIDAY WHEN STRONG COLD FRONT ARRIVES.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
UPDATE...MARSILI
SYNOPSIS...MARSILI
SHORT TERM...AGD
LONG TERM...JT
AVIATION...LASHLEY
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1230 AM EDT THU SEP 19 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 358 PM EDT WED SEP 18 2013
A BROAD UPPER LEVEL RIDGE TO OUR SOUTH IS BEING ROUNDED BY VERY
WEAK AND VERY SUBTLE UPPER LEVEL WAVES...POORLY RESOLVED BY
GUIDANCE. THESE WEAK WAVES MAY BE ABLE TO SPARK A SHOWER OR STORM
AT TIMES THROUGH LATE THURSDAY NIGHT INTO FRIDAY NIGHT...WHEN THE
MAIN FRONTAL SYSTEM WILL PUSH THROUGH THE AREA AND BRING A MORE
SUBSTANTIAL OPPORTUNITY FOR STORMS TO THE AREA BEFORE DRY AND
COOLER CONDITIONS RETURN FOR THE REMAINDER OF THE FORECAST PERIOD.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 946 PM EDT WED SEP 18 2013
RADAR LOOP SHOWS SOME STORMS IN NORTHWEST INDIANA WITH A LITTLE
SHOWER ALSO OVER NORTHERN CARROLL COUNTY. THE LARGER AREA OF
STORMS IS MOVING SOUTHEAST. LOOKING AT HRRR MODEL OUTPUT IT
APPEARS THAT THIS WILL WEAKEN AS IT HEADS THIS WAY SIMILAR TO THE
ECHOES THAT ARE NOW ONLY A BRIEF SHOWER. STILL IT LOOKS POSSIBLE
THAT STORMS COULD REACH THE NORTHERN COUNTIES OF THE AREA OVER THE
NEXT FEW HOURS AND THUS WENT WITH A SLIGHT TO LOW END CHANCE THERE
DURING THIS TIME. ALSO SEEING SOME LIGHT RAIN OVER CENTRAL
ILLINOIS PROMPTED BY A WEAK UPPER WAVE AND SOME ISENTROPIC LIFT
AND THIS COULD MOVE INTO THE AREA AFTER 6Z...SO WENT WITH A SLIGHT
CHANCE ACROSS ALL OF CENTRAL INDIANA THEN. THIS SHOULD ALSO COVER
SOME REDEVELOPMENT OVER THE NORTHEASTERN COUNTIES THAT THE HRRR IS
SHOWING...ALTHOUGH CONFIDENCE IN THIS SOLUTION IS LOW AND THUS NO
HIGHER THAN 20 POPS WILL BE USED DURING THAT TIME.
GOING LOW TEMPERATURES IN THE MIDDLE 60S LOOK GOOD BASED ON
EXPECTED CLOUD COVER AND CURRENT TEMPERATURES.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
ISSUED AT 358 PM EDT WED SEP 18 2013
MAY SEE SOME SHOWERS OR STORMS DEVELOP FROM MIDDAY ONWARD
TOMORROW...AGAIN NO MORE THAN SCATTERED IN NATURE. HIGHER POPS ARE
ONLY MERITED FRIDAY INTO FRIDAY NIGHT AS THE FRONT FINALLY PUSHES
THROUGH THE AREA. SPC SEE TEXT OUTLOOK DAY 3 APPEARS REASONABLE
GIVEN THE TIME OF DAY THE FRONT IS EXPECTED...BUT INSTABILITY AND
SHEAR ARE MODEST AT BEST AND DO NOT EXPECT MUCH MORE THAN ISOLATED
SEVERE IF THAT.
ON TEMPS...CONSENSUS NUMBERS LOOKED OK THROUGHOUT GIVEN EXPECTED
THICKNESSES AND PRECIP COVERAGE...EXCEPT FOR SATURDAY WHERE A
WARMER MOS BLEND WAS PREFERRED WITH SKIES LIKELY TO CLEAR AND
AMPLE SUN EXPECTED.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
ISSUED AT 220 PM EDT WED SEP 18 2013
DRY FORECAST THIS PERIOD WITH SEASONABLE TEMPERATURES.
GFS AND ECMWF DEPICT A CUT OFF UPPER LOW MOVING THROUGH THE
APPALACHIANS EARLY IN THE PERIOD WHILE RIDGING ALOFT AND STRONG
SUBSIDENCE OVER THE MISSISSIPPI RIVER VALLEY PROVIDES A NORTHERLY
FLOW OF AIR AS IT SLOWLY BUILDS EAST DURING THE PERIOD.
AS THE RIDGE MOVES EAST OVER INDIANA BY THE MIDDLE OF NEXT
WEEK...TEMPS WILL SLOWLY MODERATE TO SLIGHTLY ABOVE NORMAL AS
RETURN FLOW BEGINS.
&&
.AVIATION /DISCUSSION FOR THE 190600Z TAFS/...
ISSUED AT 1230 AM EDT THU SEP 19 2013
MVFR CONDITIONS WILL BE POSSIBLE EARLY THIS MORNING. A RETURN TO VFR
IS EXPECTED BY LATE MORNING.
MODELS DEPICT A LOWERING CIGS AND VISIBILITIES DIURNALLY OVERNIGHT
AS HIGH DEW POINTS AND DIURNAL COOLING IS ONGOING. THEN MODELS ONCE
AGAIN HINT AT ANOTHER BIT OF LIFT PUSHING THROUGH THE AREA ON LATE
THIS AFTERNOON...HOWEVER...CONFIDENCE IN THIS WEAK FEATURES REMAIN
LOW AND WILL STICK WITH VFR AND VCSH ATTM. BETTER CHANCES FOR RAIN
WILL COME LATER ON FRIDAY...JUST OUTSIDE OF THE TAF FORECAST PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...CP
SHORT TERM...NIELD
LONG TERM....PUMA
AVIATION...SMF
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AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1145 PM CDT WED SEP 18 2013
.UPDATE...
ISSUED AT 847 PM CDT WED SEP 18 2013
AN UPDATE WAS JUST SENT TO INCREASE POPS OVER THE NORTH HALF OF
THE AREA AFTER MIDNIGHT. LLJ PROGGED TO STRENGTHEN TO 40+KTS LATE
TONIGHT AND IS POINTED AT NORTHEAST IOWA DURING THE EARLY MORNING
HOURS. SATELLITE IMAGERY IS SHOWING AN AREA OF MID CLOUDS DRIFTING EAST
THROUGH NORTH CENTRAL IA AND THEY SHOULD BE OVER THE NE QUARTER
OF THE STATE BY MIDNIGHT...WHERE THE NOSE OF THE LLJ IS AIMED. THE
PAST SEVERAL RUNS OF THE HRRR HAVE BEEN CONSISTENTLY DEVELOPING
CONVECTION IN THE SAME AREA. GIVEN THESE FACTORS THERE WAS ENOUGH
CONFIDENCE TO INCREASE POPS INTO THE CHANCE CATEGORY BETWEEN 06Z
AND 12Z.
DLF
&&
.SYNOPSIS...
ISSUED AT 310 PM CDT WED SEP 18 2013
12Z UA ANALYSIS HAD AN 850MB LOW NEAR KBIS WITH A DEVELOPING WARM
FRONT RUNNING SOUTHEAST TO KSTL. A LLJ RAN FROM WEST TEXAS INTO
SOUTHWEST IOWA AND DEW POINTS WERE IN THE MID TEENS FROM MEXICO INTO
SOUTHERN MINNESOTA. SATELLITE/RADAR TRENDS SHOW THE SMALL COMPLEX OF
STORMS MOVING INTO NORTHEAST IOWA WITH GENERALLY CLEAR SKIES ACROSS
THE PLAINS AND IOWA.
18Z SFC ANALYSIS HAS A LOW NEAR KPIR WITH A WARM FRONT RUNNING
SOUTHEAST TO NEAR KMLI AND THEN SOUTH TO NEAR K3LF. RAIN COOLED AIR
REMAINED ACROSS NORTHEAST IOWA AND NORTHWEST ILLINOIS. DEW POINTS
WERE IN THE 60S ACROSS THE MIDWEST WITH POCKETS OF 70S IN THE
SOUTHERN PLAINS.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 310 PM CDT WED SEP 18 2013
SATELLITE TRENDS INDICATE LITTLE IN THE WAY OF NEW CLOUDS HAVE
FORMED DURING THE AFTERNOON SO THE THREAT OF NEW CONVECTION PRIOR TO
SUNSET IS VERY LOW.
THE MCS AND LIFT TOOLS ARE SUGGESTING SOME ISOLATED WEAK CONVECTION
MAY DEVELOP OVER THE AREA BY LATE EVENING AND MOVE EAST.
HOWEVER...THE BETTER FORCING/MOISTURE IS WEST OF THE AREA. THE MCS
AND LIFT TOOLS ARE SUGGESTING ANOTHER STORM COMPLEX DEVELOPING ALONG
THE IA/MO BORDER LATE TONIGHT AND POSSIBLY ARRIVING IN THE WESTERN
CWFA AROUND SUNRISE THURSDAY. THUS MOST OF THE AREA SHOULD SEE DRY
CONDITIONS TONIGHT.
IF THE STORM COMPLEX DEVELOPS AS SUGGESTED ALONG THE IA/MO
BORDER...THEN THIS COMPLEX WOULD MOVE ACROSS THE WESTERN HALF OF THE
CWFA DURING THE MORNING. CLOUD COVER/PRECIPITATION MAY MAKE IT
DIFFICULT TO ACHIEVE HIGHS IN THE MID AND UPPER 80S THURSDAY.
NEW CONVECTION IS EXPECTED TO DEVELOP THURSDAY AFTERNOON AHEAD OF
THE APPROACHING COLD FRONT. MOISTURE LEVELS IN THE ATMOSPHERE ARE
PROJECTED TO BE QUITE HIGH UP INTO THE MID LEVELS. THUS THE
POTENTIAL FOR ANY SEVERE STORMS APPEARS TO BE LOW. ..08..
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 310 PM CDT WED SEP 18 2013
MODERATE TO HEAVY RAIN EVENT THURSDAY NIGHT...THEN SEASONABLY COOL.
OVERVIEW...INITIALIZATION AND VERIFICATION AVERAGE WITH MOST SOLUTIONS
UNDERPLAYING MOISTURE IN CENTRAL PLAINS AND SW MONSOON PLUME. PACIFIC
ENERGY IS ALSO UNDERPLAYED WITH 10 TO 20 METER HEIGHT FALLS UNDERDONE.
THIS SHOWS UP IN SURFACE PRESSURE FIELDS. VERIFICATION AT 18Z SUPPORTS
FORCING OF HI-RES ECMWF/UKMET AND NAM-WRF WITH HI- RES ECMWF CLOSEST
ON MOISTURE FLUX WITH COOL FRONT PASSING THURSDAY NIGHT. THEN...EARLY
FALL HIGH PRESSURE TO BRING SEVERAL DAYS OF NICE LATE SEPTEMBER WEATHER
WITH LOW HUMIDITY.
THURSDAY NIGHT...STRAIGHTFORWARD FORECAST. PW/S OF 1.5" OF DEEP MOISTURE
AHEAD OF DEEP SURFACE AND UPPER LEVEL TROUGH TO BRING A LARGE SWATH
OF SHOWERS AND THUNDERSTORMS. LITTLE OR NO SURFACE WAVE SUGGESTED AT
THIS TIME...LOCAL TOOLS INDICATE ALMOST ALL THE AREA TO PICK UP .5 TO
LOCALLY NEAR 1.5 INCHES OF RAIN. WENT WITH 80-90 POPS WITH FRONT PASSING
BETWEEN MIDNIGHT AND 7 AM. DEEP MOISTURE...OVERNIGHT FORCING AND HIGH
FREEZING LEVELS DO NOT SUPPORT A SEVERE RISK AT THIS TIME WITH STRONGEST
STORMS PRODUCING MAYBE 30-40 MPH WINDS. LATER SHIFTS WILL NEED TO REASSESS
AS NAM- WRF IS TOO UNSTABLE IN BL AS HAS BEEN MORE OFTEN THE CASE THIS
WARM SEASON. NOTE: IF A WAVE FORMS...LOCALLY 2+ INCH AMOUNTS WILL BE
POSSIBLE.
FRIDAY...KEPT MORNING POPS EAST SECTIONS WITH CLEARING BY MID DAY AND
BREEZING NW WINDS OF 10-20+ MPH. HIGHS MOSTLY 70-75F FOR A NICE DAY.
FRIDAY NIGHT THROUGH WEDNESDAY...MOSTLY FAIR AND SLIGHTLY BELOW NORMAL
TEMPERATURES AS CANADIAN HIGH PRESSURE DOMINATES. HIGHS GENERALLY UPPER
60S TO MIDDLE 70S WITH LOWS 45 TO 55 DEGREES. GOOD WEATHER FOR MOST
OUTDOOR ACTIVITIES. ANOTHER PROMISING RAIN EVENT POSSIBLE BY LATE IN
THE WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1140 PM CDT WED SEP 18 2013
THE MAIN CONCERN WILL BE THE THUNDERSTORM POTENTIAL OVERNIGHT.
THERE ARE STILL INDICATIONS OF A THUNDERSTORM COMPLEX DEVELOPING
OVER EAST CENTRAL IOWA AFTER MIDNIGHT AND MOVING NORTHEAST THROUGH
NORTHWEST IL BY THURSDAY MORNING. IT APPEARS THE BETTER FORCING
WILL BE NORTH OF I80 SO LIMITED THE MENTION OF THUNDER TO THE CID
AND DBQ TAFS BETWEEN 10Z AND 14Z. OTHERWISE EXPECT MAINLY VFR
CONDITIONS OVERNIGHT THURSDAY. A COLD FRONT WILL BE APPROACHING
THE AREA THURSDAY AFTERNOON. THUNDERSTORMS AHEAD OF THE FRONT
COULD REACH CID AND DBQ AS EARLY AS LATE THURSDAY AFTERNOON. THE
THUNDERSTORMS WILL SPREAD SOUTHEAST DURING THE EVENING. THE
STRONGEST STORMS SHOULD OCCUR LATE IN THE AFTERNOON AND EARLY IN
THE EVENING. IFR/MVFR CONDITIONS WOULD ACCOMPANY THE STRONGER STORMS.
ALSO SOUTHWEST WINDS AHEAD OF THE FRONT WILL GUST TO 20 TO 25KTS
DURING THE AFTERNOON.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...DLF
SYNOPSIS...08
SHORT TERM...08
LONG TERM...NICHOLS
AVIATION...DLF
AREA FORECAST DISCUSSION
NWS GOODLAND KS
358 AM MDT THU SEP 19 2013
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 358 AM MDT THU SEP 19 2013
FORECAST PROBLEMS WILL BE PRECIPITATION CHANCES TODAY...HOW COOL TO
MAKE HIGHS AND LOWS THROUGH FRIDAY NIGHT AND HOW MUCH TO WARM THINGS
UP ON SATURDAY. SATELLITE SHOWING AN ACTIVE FLOW FROM THE PACIFIC
INTO NORTH AMERICA. THE FLOW WAS AMPLIFYING SOME OVER THE PACIFIC...
ESPECIALLY ALONG THE WEST COAST. ONE SYSTEM IS PUSHING EAST ALONG THE
U.S AND CANADIAN BORDER. OUTFLOW FROM THUNDERSTORM CLUSTER TO OUR
NORTH HAS PUSHED THROUGH THE AREA WITH A COLD FRONT APPROACHING FROM
THE NORTHWEST.
AT JET LEVEL...THE SREF WAS DOING A LITTLE BETTER WITH THE JET
DEPICTION OVER OUR AREA. AT MID LEVELS...MODELS WERE HAVING A LITTLE
TROUBLE THE SPEED AND AMPLITUDE OF THE NORTHERN LOW. AT THIS TIME
IT APPEARS THE GFS AND UKMET WERE DOING A LITTLE BETTER THAN THE
ECMWF AND CANADIAN. THE RUC WAS CATCHING THE INITIAL WIND FIELD THE
BEST WITH THE ECMWF NOT TOO FAR BEHIND. THE UKMET AND GFS WERE DOING
A LITTLE BETTER THAN THE OTHER OUTPUT ON THE LOW LEVEL THERMAL
FIELD.
TODAY/TONIGHT...INTERESTING PRECIPITATION FORECAST. INITIAL ROUND OF
THUNDERSTORMS WERE CAUSED BY INITIAL SURFACE TROUGH AND OUTFLOW
BOUNDARY FROM CLUSTER OF THUNDERSTORMS THAT MOVED TO THE NORTH OF OUR
FORECAST AREA. HOWEVER ADDITIONAL DEVELOPMENT IS NOW OCCURRING IN
ADVANCE OF COLD FRONT WHICH IS VERY NEAR THE NORTHWEST CORNER OF THE
FORECAST AREA. ALSO AT THIS TIME...MAIN SHORTWAVE TROUGH ROTATING
AROUND NORTHERN UPPER LOW IS BEGINNING TO MOVE IN FROM THE WEST.
ALSO THE RIGHT REAR QUADRANT OF THE JET IS NEAR/OVER THE WESTERN END
OF THE FORECAST. DURING THE DAY THEY ALL HANDLE IT DIFFERENTLY.
HOWEVER...BY THE END OF THE AFTERNOON INTO THE EARLY AFTERNOON...THE
RIGHT REAR QUADRANT IS OVER OR NEAR THE EASTERN END OF THE AREA. IN
ADVANCE OF ALL THESE FEATURES THERE APPEARS ENOUGH ELEVATED CAPE WITH
FAVORABLE THETA-E LAPSE RATES TO ALLOW FOR A GOOD RESPONSE TO THE
LIFT. AT THIS TIME IT LOOKS LIKE THE FAVORED AREA FOR THUNDERSTORMS
IS ALONG AND EAST OF THE COLORADO BORDER...GETTING HIGHER AS YOU GO
EAST. KEPT THIS GENERAL IDEA FROM THE DAY SHIFT BUT RAISED POPS
SLIGHTLY FURTHER EAST. THUNDERSTORMS LOOK TO BE DONE BY LATE IN THE
DAY.
DEFINITELY LOOKS COOLER. THE QUESTION IS HOW MUCH. THE AMOUNT OF
TEMPERATURE CHANGE OVER YESTERDAY WOULD YIELD SLIGHTLY COOLER
TEMPERATURES THAN WHAT I HAVE IN THERE NOW. DID MAKE SLIGHT
ADJUSTMENTS COOLER IN LINE WITH THE BIAS ADJUSTMENT TO THE 850 MB
TEMPERATURES. THIS TENDED TO BE IN THE MIDDLE OF THE GUIDANCE. WILL
BE A RATHER COOL NIGHT TONIGHT WITH LITTLE CLOUD COVER AND LIGHT
WINDS. MODELS DIFFER ON WHERE THE LIGHTEST WINDS WILL BE. AT THIS
TIME IT LOOKS THEY WILL BE IN THE WESTERN AND NORTHERN SECTIONS AND
ADJUSTED ACCORDINGLY.
FRIDAY/FRIDAY NIGHT...MID/UPPER RIDGE BUILDING INTO THE AREA WILL
MAKE FOR DRY CONDITIONS AND LITTLE TO NO CLOUD COVER. SURFACE RIDGE
JUST PULLING OFF TO THE EAST DURING THE DAY WITH LIGHT AND
VARIABLE WINDS...ESPECIALLY IN THE EAST. MODELS ARE INDICATING
TEMPERATURES NEAR WHAT THEY ARE TO BE TODAY. ONLY MADE SLIGHT
ADJUSTMENTS BASED ON THAT. SOME DIFFERENCES IN HOW COOL TO MAKE THE
MINS. THE NAM STARTS WARM ADVECTION MUCH FASTER WITH THE OTHER MODELS
SLOWER. IT SHOULD BE WARMER BUT AM NOT GOING AS WARM AS THE NAM.
SATURDAY/SATURDAY NIGHT...MID/UPPER LEVEL RIDGE STARTS PUSHING EAST
LATE IN THE DAY AND ESPECIALLY IN THE NIGHT WITH SOUTHWEST FLOW
ALOFT DEVELOPING OVER THE AREA. THIS RIDGE PLUS VERY DRY/WELL MIXED
AIR MASS ALOFT WILL KEEP CONDITIONS DRY...DESPITE THE FACT AN UPPER
JET APPROACHES THE WESTERN PORTIONS OF THE AREA LATE IN THE NIGHT.
SHOULD BE WARMER...QUESTION IS HOW MUCH WARMER. NAM CONTINUES TO BE
THE MOST AGGRESSIVE WITH THIS. WIND FIELD AND CONSENSUS OF 850 MB
TEMPERATURES SUPPORT GOING COOLER. THIS IS CLOSE TO WHAT CURRENT
FORECAST HAS IN THERE AND ONLY MADE SLIGHT ADJUSTMENTS.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 300 AM MDT THU SEP 19 2013
A SHORTWAVE TROUGH WILL QUICKLY MOVE THROUGH SUNDAY NIGHT. THE
STRONGEST FORCING WILL BE NORTH OF THE FORECAST AREA ACROSS NEBRASKA
WHERE GFS ENSEMBLE MEAN QPF VALUES ARE HIGHEST. ISOLATED TO
SCATTERED CONVECTION SHOULD IMPACT THE WESTERN PORTION OF THE
FORECAST AREA BY SUNDAY EVENING AND THEN OVERSPREAD THE REST OF
THE AREA OVERNIGHT. THE GREATEST RAIN CHANCES AND POTENTIAL FOR
THE HIGHEST RAINFALL AMOUNTS WILL BE OVER ROUGHLY THE NORTHEASTERN
HALF OF THE FORECAST AREA. SLIGHTLY COOLER TEMPERATURES WILL
ARRIVE BEHIND THIS SHORTWAVE AND ASSOCIATED COLD FRONT ON MONDAY
BUT COLD AIR ADVECTION IN THE WAKE OF THIS SYSTEM IS BRIEF AND
INSIGNIFICANT. STRONG EAST TO WEST ORIENTED MID/UPPER FLOW WILL BE
SITUATED OVER THE NORTHERN ROCKIES AND NORTHERN PLAINS ON TUESDAY.
BY MID WEEK A LARGE TROUGH EVOLVES OVER THE WESTERN CONUS. MODELS
DIFFER ON HOW THIS TROUGH WILL EVOLVE BY MID WEEK WITH GFS AND
ECMWF DIFFERING ON THE POSITION OF CLOSED UPPER LOW...MEANWHILE
GFS ENSEMBLE MEAN DEPICTS A MORE OPEN/PROGRESSIVE TROUGH. IN
EITHER SCENARIO...SIGNIFICANT IMPACTS TO OUR AREA ARE NOT EXPECTED
THROUGH THE END OF THE EXTENDED PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1154 PM MDT WED SEP 18 2013
A FEW THUNDERSTORMS HAVE DEVELOPED ALONG THE PRE-FRONTAL TROUGH
MOVING ACROSS THE CENTRAL HIGH PLAINS REGION TONIGHT. A FEW STORMS
ARE MOVING NORTHEASTWARD IN THE VICINITY OF MCK AND GLD AND ARE
EXPECTED TO BE PRESENT THROUGH ABOUT 09Z. AFTER 09Z...STORMS ARE
EXPECTED TO DIMINISH AND MOVE OUT OF THE REGION. VFR CONDITIONS
ARE EXPECTED THROUGH THE ENTIRE TAF PERIOD AT BOTH MCK AND GLD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM..BRB
LONG TERM...BULLER
AVIATION...LOCKHART
AREA FORECAST DISCUSSION
NWS JACKSON KY
217 AM EDT THU SEP 19 2013
.UPDATE...
ISSUED AT 217 AM EDT THU SEP 19 2013
HAVE SENT A MINOR UPDATE INCORPORATING RECENT OBSERVATIONS.
UPDATE ISSUED AT 1030 PM EDT WED SEP 18 2013
FRESHENED UP THE SKY COVER AND HOURLY TEMPERATURES AND DEW POINTS TO
ACCOUNT FOR THE LATEST TRENDS. SOME PARTIAL CLEARING WILL WORK IN
FROM THE WEST...HOWEVER BELIEVE THAT LOW CLOUDS WILL FILL BACK IN
DURING THE OVERNIGHT WITH HIGH MOISTURE IN THE 1000-850 MB LAYER
LINGERING. LEFT THE POPS AS IS...ALTHOUGH THE LATEST HRRR HAS BACKED
OFF ON THE UPTICK IN CONVECTION TOWARDS DAWN FOR THE NORTHEASTERN
PORTION OF THE AREA.
UPDATE ISSUED AT 807 PM EDT WED SEP 18 2013
A FEW SHOWERS WILL WIND DOWN ACROSS NORTHEASTERN KENTUCKY IN THE NEXT
HOUR. THE LATEST SHORT RANGE MODELS SHOW A LULL IN THE ACTIVITY
THROUGH THE OVERNIGHT...BEFORE AN UPTICK OCCURS TOWARDS DAWN IN THE
NORTHEASTERN HALF OF THE AREA...AS A WEAK SHORT WAVE TROUGH MOVES
SOUTHEAST ACROSS OHIO VALLEY. HAVE BUMPED UP THE POPS A BIT
CONSIDERING THE DECENT MODEL AGREEMENT. ALSO ADDED SOME PATCHY FOG
AND MADE THE VALLEY TEMPERATURES A BIT MORE UNIFORM WITH ALL OF THE
CLOUD COVER AND STEADY DEW POINTS IN THE LOW 60S.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 307 PM EDT WED SEP 18 2013
THE MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE MAJOR UPPER AIR
FEATURES...HOWEVER THERE IS QUITE A BIT OF DIFFERENCE IN HOW THEY
HANDLE THE PRECIPITATION FORECASTS OVER THE NEXT 36 HOURS. A WARM
FRONT HAS MOVED TO THE NORTHEAST OF THE AREA AND EASTERN KENTUCKY IS
NOW IN THE WARM SECTOR WITH A SURFACE HIGH OFF THE EAST COAST AND A
SURFACE RIDGE EXTENDING ACROSS EASTERN KENTUCKY. A COLD FRONT IS OVER
THE HEARTLAND AND WILL BE APPROACHING THE AREA...HOWEVER WILL NOT
MOVE INTO EASTERN KENTUCKY UNTIL SATURDAY. THIS ALLOWS FOR THE GULF
TO BE OPENED UP AND THERE WILL BE SOME FAIRLY WARM...MOIST AND
CONDITIONALLY UNSTABLE AIR OVER THE AREA. THE MODELS DIFFER AS TO
WHEN WEAK LITTLE PERTURBATIONS WILL BE ABLE TO KICK OFF ANY
CONVECTIVE ACTIVITY. FROM EXPERIENCE...EXPECT THAT THERE WILL BE AN
AFTERNOON AND EVENING MAXIMUM OF CONVECTIVE ACTIVITY...HOWEVER THERE
MAY BE SOME UNEXPECTED LITTLE POP-UPS DURING THE OFF HOURS. THE MODEL
BLEND HANDLED THE TEMPERATURES VERY WELL AND JUST MADE SOME MINOR
TWEAKS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 307 PM EDT WED SEP 18 2013
ON FRIDAY A COLD FRONT EXTENDING FROM THE WESTERN GREAT LAKES INTO
THE MID MS VALLEY WILL BE MOVING EAST AS AN UPPER LEVEL SHORT WAVE
TROUGH PUSHES EAST THROUGH THE PLAINS. THE UPPER TROUGH AND SURFACE
COLD FRONT WILL MOVE EAST WITH RAIN CHANCES INCREASING ACROSS THE
AREA AS WE HEAD INTO THE WEEKEND. MOST RECENT RUNS OF THE VARIOUS
OPERATIONAL MODELS ARE POINTING TOWARDS SLOW FRONTAL MOVEMENT WITH
THE FRONT MOVING ACROSS THE AREA ON SATURDAY...AND LIKELY STALLING
OUT. THE LATEST WPC GUIDANCE IS ALSO FAVORING THIS IDEA WITH THE
FRONT APPROACHING THE FORECAST AREA AT 12Z SATURDAY. OF THE
OPERATIONAL MODELS THE 12Z NAM IS THE OUTLIER...AS IT PUSHES THE
UPPER TROUGH AND SURFACE FRONT THROUGH MUCH QUICKER...WITH THE FRONT
EAST OF KY BY 15Z SATURDAY. WILL LEAN AWAY FROM THE NAM FORECAST AS
ALL THE OTHER MODELS ARE MUCH SLOWER. THE 12Z GFS SHOWS THE SOUTHERN
PART OF THE UPPER TROF SLOWING DOWN WITH AN UPPER LOW CLOSING OFF IN
THE VICINITY OF EASTERN KY BY SUNDAY. THE 00Z ECMWF AND 12Z GEM ALSO
SUPPORT THE IDEA OF SLOW MOVEMENT WITH AN UPPER LOW FORMING OVER THE
UPPER SOUTH INTO THE TN VALLEY. OVERALL...MODELS AND WPC GUIDANCE
POINT TOWARDS WET CONDITIONS OVER THE WEEKEND. THE LATEST BLENDED
LOAD ALSO SUPPORTS THIS. EXACTLY HOW LONG THE SLOW MOVING UPPER LOW
AND ASSOCIATED SURFACE LOW LINGER NEARBY AND CONTINUE TO AFFECT
OUR WEATHER IS STILL UNCERTAIN. THE 00Z ECMWF POINTS TOWARDS RAIN
CHANCES LINGERING INTO THE MIDDLE OF NEXT WEEK...WHILE THE 12Z GFS
IS DRIER...WITH LESS OF A CHANCE OF RAIN AFTER MONDAY. WHILE THE
STANDARD BLENDED LOAD RESULTED IN A CHANCE OF RAIN IN THE SOUTHEAST
ON TUESDAY AND WEDNESDAY HAVE DECIDED TO FOLLOW THE CONSENSUS OF
NEIGHBORING WFOS AND WILL GO WITH A DRY FORECAST ON TUESDAY AND
WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 217 AM EDT THU SEP 19 2013
CONDITIONS STARTED OUT MOSTLY VFR. HOWEVER...DETERIORATION IS
EXPECTED OVERNIGHT. IFR IS FORECAST FOR MOST LOCATIONS DUE TO LIGHT
FOG. HOWEVER...CONFIDENCE IS LOW CONCERNING HOW FAR THE VISIBILITY
DROPS. FOG WILL DISSIPATE ON THURSDAY MORNING...BUT MVFR CEILINGS ARE
EXPECTED TO PERSIST IN MOST AREA UNTIL EARLY AFTERNOON...BEFORE
SCATTERING OUT AND LEAVING VFR TO FINISH THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...JJ
LONG TERM...SBH
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1153 PM CDT Wed Sep 18 2013
.UPDATE...
ISSUED AT 1153 PM CDT WED SEP 18 2013
The aviation section has been updated for the 06Z TAF issuance.
&&
.SHORT TERM /Tonight through Friday night/...
ISSUED AT 230 PM CDT WED SEP 18 2013
The showers and isolated thunderstorms that occurred this morning
have all but dissipated by mid afternoon. Partial clearing will
continue to spread slowly east. The trend toward low and mid level
drying is indicated by RAP and nam model soundings. This drying
appears to be in response to a gradual rebuilding of the 500 mb
ridge that was flattened by a weak impulse this morning.
Through Thursday...the mid level ridge will continue to slowly build
over our region. This should continue to suppress most convection
over the Lower Ohio and Mid Mississippi Valleys. Will keep slight
chance pops during the peak heating hours from roughly 18z to 00z to
account for isolated diurnally driven storms.
A rather strong cold front will approach from the northwest on
Thursday night...reaching southern Illinois and southeast Missouri
on Friday. The front will continue moving southeast across western
Kentucky and southwest Indiana on Friday evening. The 09z sref
timing looks reasonable. A deepening upper trough will enhance lift
along the frontal zone...and deep layer moisture will be high for
this time of year /sref precip water values about 1.9 inches/. Looks
like the first widespread significant rainfall of the month will
occur. Storm total qpf should be at least one half inch...with some
1 inch amounts likely in heavier convection. Severe weather
potential will depend on how much sunshine and diurnal heating takes
place ahead of the front. Isolated severe convection is currently
forecast by SPC /see day 3 outlook/.
South to southwest low level flow will keep unseasonably warm and
humid conditions in place through Friday. The nam continues to have
problems with too much moisture in the model...as shown in its high
pops and abundant cloudiness. The warmer gfs mos highs look better
for Thursday.
.LONG TERM /Saturday through Wednesday/...
ISSUED AT 230 PM CDT WED SEP 18 2013
Main issue in the extended looks to be with how quickly an upper
level trof will move east out of the region over the weekend. Models
seem to be trending toward a less progressive solution in this
respect. Both the operational GFS and ECMWF suggest showers will
linger into Saturday along and south of the Ohio River, east of
the H50 trof axis. Will bump up precip chances on Sat into the 40
to 50 percent range over much of the Pennyrile region of western
KY.
Otherwise, the most noticeable change over the weekend will be
another transition to much cooler and less humid conditions. Highs
both Saturday and Sunday will likely stay down in the 70s, with lows
Sat night mostly in the 50 to 55 degree range.
As we head into next week, it now appears as though an Omega
Blocking pattern will become established along the MS River Valley.
This should keep things quite dry across our region, with sunny,
warm afternoons and cool nights. Temperatures will warm a touch each
day, and most locations will likely be back into the middle 80s by
Wednesday afternoon. Humidity levels should stay low though.
&&
.AVIATION...
ISSUED AT 1153 PM CDT WED SEP 18 2013
Some mid-level ceilings and light showers over central Illinois
may try to clip KEVV late tonight. Elected not to mention any
precipitation as it would likely be of little impact. Still
looking at 5kts of a south wind overnight at all sites, so will
not mention fog. The only issue may be at KOWB where they are
nearly saturated as of 04Z.
Added in a minor SSW gust in most locations for Thursday, due to
a decent pressure gradient and decent mixing expected. Still
cannot rule out some isolated to scattered diurnal convection, but
will not mention anything in the forecast at this time. Even if
there is development, the coverage would likely be too sparse to
mention.
Light south winds and mid clouds can be expected throughout the
area Thursday evening.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...DRS
SHORT TERM...MY
LONG TERM...GM
AVIATION...DRS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1208 AM EDT THU SEP 19 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 148 PM EDT WED SEP 18 2013
A WARM FRONT WILL PUSH NORTHWARD THROUGH LOWER MICHIGAN TONIGHT
LEADING TO SOME SHOWERS AND THUNDERSTORMS. SOUTHWEST WINDS WILL
INCREASE THURSDAY ALLOWING FOR AND UNSEASONABLY WARM DAY. MOISTURE
FROM THE GULF OF MEXICO WILL STREAM INTO THE AREA THURSDAY NIGHT
AND EARLY FRIDAY AHEAD OF A COLD FRONT. AS THIS FRONT PUSHES
THROUGH THE REGION FRIDAY...A PERIOD OF SHOWERS AND THUNDERSTORMS
CAN BE EXPECTED.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 148 PM EDT WED SEP 18 2013
THE MAIN CHALLENGE IN THE SHORT TERM DEALS WITH THE TIMING AND
STRENGTH OF THE CONVECTION. STORMS IN NW ILLINOIS ARE SHOWN TO
WEAKEN AS THEY HEAD TOWARD CHICAGO THIS AFTERNOON. HRRR SHOWS
CONVECTION REDEVELOPING OVER LAKE MI LATER TONIGHT AND MOVING INTO
THE HOLLAND TO MUSKEGON REGION. THIS MAKES SENSE WITH A
STRENGTHENING LOW LEVEL JET ACCOMPANYING THE WARM FRONT THAT
FEATURES ELEVATED INSTABILITY. NOT ALL MODELS HAVE THIS...BUT THE
HRRR TENDS TO HANDLE THE CONVECTION BETTER THAN MOST. WILL
DECREASE POPS INLAND TONIGHT...BUT CLOSER TO LAKE MI WILL KEEP THE
LIKELY VALUES GOING. SEVERE WEATHER IS NOT FORECASTED...BUT
PERHAPS A HEAVY RAIN THREAT MAY EXIST.
A LULL IN THE CONVECTION IS EXPECTED THU AS NO FOCUSING MECHANISM
IS SHOWN. IT WILL BE A WARM AND INCREASINGLY HUMID. IT DOES BECOME
RATHER UNSTABLE...SO WILL HOLD ONTO A LOW POP FOR STORMS.
I RAISED POPS FOR FRIDAY. WITH PWAT VALUES APPROACHING 2 INCHES
AND A FRONT PRESSING IN ALONG WITH LIFT...IT SHOULD BE RATHER WET
AT TIMES. MODELS HAVE TRENDED SOMEWHAT FASTER WITH THE FRONT...SO
WE MAY BE ABLE TO START DRYING THINGS OUT FROM THE WEST BEFORE THE
END OF THE DAY. WILL WAIT TO SEE IF THIS TREND PERSISTS BEFORE
CHANGING FRIDAYS FORECAST. I DID LOWER POPS FOR FRIDAY NIGHT
BECAUSE OF THIS. AS FOR SEVERE WEATHER...THE STRONGER DEEP LAYER
SHEAR IS SHOWN TO LAG BEHIND THE COLD FRONT...SO SOMEWHAT OF A
LIMITED RISK. STILL WITH BETTER INSTABILITY DEVELOPING AND
INCREASING WIND FIELDS ALONG WITH A LOW LEVEL JET MOVING IN AND
STRENGTHENING...A RISK STILL EXISTS. WILL NEED TO MONITOR TRENDS
CLOSELY IN THE COMING DAYS.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 243 PM EDT WED SEP 18 2013
AN UNEVENTFUL PERIOD IS EXCEPTED FOR THIS WEEKEND AND INTO THE
FIRST HALF OF NEXT WEEK. HIGH PRESSURE OVER THE UPPER MIDWEST ON
SATURDAY WILL SLOWLY MOVE OVER THE GREAT LAKES BY LATE IN THE
WEEKEND. THIS HIGH WILL BE STALLED OVER THE AREA AS A STORM SYSTEM
MOVES UP THE EAST COAST THROUGH THE FIRST HALF OF THE WORK WEEK.
SO FAIR WEATHER SHOULD PREVAIL.
LOWERED TEMPS A BIT FOR SATURDAY AND SUNDAY AS WE WILL BE UNDER A
THERMAL TROUGH . BOTH DAYS SHOULD SEE HIGHS STAYING IN THE 60S. WE
SHOULD SEE A WARM UP INTO THE WORK WEEK. HOWEVER LOW LEVEL FLOW
WILL BE FROM THE EAST OR SOUTHEAST...SO ANY MODERATION OF TEMPS
WILL BE GENTLE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1159 PM EDT WED SEP 18 2013
THE POTENTIAL AND TIMING OF THUNDERSTORMS CONTINUES TO BE
PROBLEMATIC SO THIS IS A LOW CONFIDENCE FCST. TSTM COMPLEXES HAVE
DEVELOPED TO OUR SOUTH AND OUR NORTH ALTHOUGH NOTHING YET IN
BETWEEN THE TWO.
WILL NOT MAKE MUCH CHANGE FROM THE PREVIOUS TAFS... KEEPING VCTS
OVERNIGHT INTO THURSDAY MORNING BUT THIS IS QUESTIONABLE. A LULL
IN CONVECTIVE POTENTIAL IS STILL EXPECTED THURSDAY AFTERNOON AND
EVENING BEFORE THE NEXT DECENT CHANCE OF TSTMS WILL COME THURSDAY
NIGHT AFTER 06Z.
OUTSIDE OF ANY TSTMS...VFR IS EXPECTED OVER THE NEXT 24 HOURS.
HOWVER THERE COULD BE SOME LIGHT FOG/HAZE DEVELOPING LATE TONIGHT
AND THURSDAY AS HIGHER DEW POINTS COME IT...POSSIBLY GIVING MVFR
VSBYS IN SPOTS.
&&
.MARINE...
ISSUED AT 148 PM EDT WED SEP 18 2013
WINDS ARE FORECASTED TO BE STRONGER THU INTO THU NIGHT. MAY NEED
SMALL CRAFT AND BEACH HAZARDS TO COVER THIS. UNTIL THEN THE
SOUTHERLY FLOW WILL KEEP WAVES UP TO AROUND 2 TO 4
FEET...ESPECIALLY OFF OF LITTLE AND BIG SABLE POINTS.
&&
.HYDROLOGY...
ISSUED AT 148 PM EDT WED SEP 18 2013
LOCALIZED HEAVY RAIN WILL BE POSSIBLE WITH THE STORMS TONIGHT AS A
LOW LEVEL JET MOVES IN PWAT VALUES CLIMB TO OVER 1.5 INCHES.
CORFIDI VECTORS SUGGESTS A LOCALIZED HEAVY RAIN THREAT MAY EXIST.
CURRENTLY IT APPEARS THAT AREAS ALONG THE LAKESHORE STAND THE
HIGHEST CHANCE FOR THE STORMS. A MORE WIDESPREAD ROUND OF STORMS
IS FORECASTED FOR THU NIGHT INTO FRI. PWAT VALUES LIKELY TO CLIMB
ABOVE 1.75 INCHES WITH ANOTHER LOW LEVEL JET PUSHING THROUGH.
CORFIDI VECTORS ALSO SUGGEST A HEAVY RAIN THREAT. HOW MUCH RAIN
FALLS WILL LIKELY DEPEND ON HOW EFFICIENT THE RAIN BECOMES AND HOW
THE CONVECTION EVOLVES. SUSPECT LOCALLY MORE THAN 2 INCHES WILL
FALL BY FRI NIGHT.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...JK
AVIATION...MEADE
HYDROLOGY...MJS
MARINE...MJS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
318 AM MDT THU SEP 19 2013
.SHORT TERM...VALID FOR TDY AND FRI...
UPPER TROUGH CROSSING THE REGION TONIGHT WILL CONTINUE TO EXERT
ITS INFLUENCE OVER OUR FORECAST AREA WELL INTO THURSDAY...
ESPECIALLY IN THE NORTHEAST ZONES. AS SUCH...SOME CHANGES HAVE
BEEN MADE FOR TODAYS FORECAST.
EARLY THIS MORNING...THE MAIN 500MB COLD POOL WAS SITUATED OVER
SOUTHWEST MONTANA. THERE WAS ANOTHER MID LEVEL COLD POOL OVER
NORTH CENTRAL MONTANA AS WELL WITH AN ASSOCIATED FRONT PUSHING
EAST/SOUTHEAST ACROSS MONTANA. THIS FEATURE WILL SLIP DOWN
THROUGH OUR ZONES BY 6AM. THERE IS A CONSISTENT EFFORT FROM THE
MODELS TO BRING IN A LOW CLOUD DECK BEHIND THIS FEATURE...THICKEST
ACROSS CUSTER AND FALLON COUNTIES. WHILE SOUNDINGS AND HRRR DATA
PARTIALLY BREAK MILES CITY OUT OF THIS IN THE AFTERNOON...THEY
SUGGEST BAKER AND FALLON COUNTY WILL PERSIST UNDER OVERCAST
CONDITIONS AS LONG AS 6PM. THIS SCENARIO IS A NOTORIOUS FORECAST
BUSTER FOR BAKER. UNLESS I SEE SOMETHING AT THE LAST MOMENT
SUGGESTING OTHERWISE...I WILL PLAN TO LOWER TEMPERATURES QUITE A
BIT IN THIS AREA.
ANOTHER CHANGE...THOUGH MINOR...WAS IN REGARD TO A TROWEL FEATURE
ON THE BACKSIDE OF THE TROUGH. THIS IS CURRENTLY GENERATING SOME
PRECIPITATION ALONG THE FRONT RANGE AND NORTHWEST MOUNTAINS. CROSS
SECTIONS SHOW SOME MODEST LIFT AND MOISTURE AS IT WORKS OVER OUR
FORECAST AREA THIS MORNING. IT WILL HAVE TO BATTLE A BRISK
DOWNSLOPE WIND...SO VIRGA AND SPRINKLES MAY BE THE MAIN
OUTCOME. HOWEVER...I HAVE SPREAD SOME LOW POPS BACK TO THE WEST
AS WELL AS A LITTLE FURTHER SOUTH INTO UPSLOPE AREAS NEAR THE BIG
HORNS FOR THE FIRST HALF OF THE DAY.
THE TROUGH AXIS WILL BE JUST EAST OF THE MONTANA/DAKOTA BORDER
BY EVENING. SO WE SHOULD SEE DECREASING CLOUDS AND WIND. LOWS MAY
DIP TO AROUND OR JUST BELOW AVERAGE FOR THIS TIME OF YEAR...MAKING
IT ONE OF THE OVERALL COOLEST WE HAVE HAD SO FAR THIS SEPTEMBER.
RIDGE BUILDS IN QUICKLY FOR TOMORROW WHICH WILL RESULT IN A NICE
BUMP IN THE MERCURY. BT
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
EXTENDED MODELS IN GOOD AGREEMENT FOR THIS WEEKEND GOING INTO
EARLY NEXT WEEK BUT DIVERGE WITH A LARGE SYSTEM ACROSS THE WESTERN
STATES BY MID NEXT WEEK. RIDGE AND ITS AXIS SHIFT EAST SATURDAY AS
AN UPPER LOW AND TROUGH MOVE ONTO THE PACIFIC NORTHWEST AND
NORTHERN CALIFORNIA COAST. SOUTHWEST FLOW ALOFT WILL PREVAIL ALONG
WITH ABOVE NORMAL TEMPERATURES AND A SLIGHT SHOWER/THUNDERSTORM
CHANCE. THE TROUGH ALONG WITH A COLD FRONT MOVE THROUGH THE
FORECAST AREA LATE SATURDAY NIGHT INTO SUNDAY MORNING BRINGING
BETTER CHANCES FOR SHOWERS WITH COOLER AND MORE NORMAL
TEMPERATURES FOR SUNDAY.
FAST ZONAL FLOW ALOFT LOOKS IN STORE FOR MONDAY AND TUESDAY WITH
MAINLY A DOWNSLOPE SURFACE FLOW KEEPING CONDITIONS DRY FOR THE
LOWER ELEVATIONS WITH SHOWERS FOR THE MOUNTAINS. BY LATE TUESDAY
INTO WEDNESDAY...AN UPPER LOW TAKES SHAPE ACROSS THE PACIFIC
NORTHWEST. MODELS DIVERGE GREATLY FROM THAT POINT ONWARD. THE GFS
TAKES THE LOW SOUTH INTO THE GREAT BASIN AREA WEDNESDAY AND
THURSDAY WHILE THE ECMWF EJECTS THE LOW NORTHEAST ACROSS MONTANA
BUT STILL KEEPING A TROUGH ACROSS THE CENTRAL AND NORTHERN
ROCKIES. EITHER SCENARIO WILL BRING INCREASING CHANCES FOR PRECIP
TO THE FORECAST AREA. HOWEVER...LOCATION AND AMOUNTS OF PRECIP
ALONG WITH TEMPEATURES VARY QUITE A BIT DEPENDING ON MODEL. WILL
KEEP CHANCE POPS FOR MID NEXT WEEK WITH HIGHEST CHANCES FOR THE
MOUNTAINS ALONG WITH A TREND TO COOLER TEMPERATURES. HOOLEY
&&
.AVIATION...
EXPECT PARTLY TO MOSTLY CLOUDY SKIES TODAY WITH VFR CONDITIONS
PREVAILING. THE EXCEPTION WILL BE ISOLATED TO SCATTERED SHOWERS
POSSIBLE ALONG AND NORTH OF A KLVM- KBIL-KBHK LINE TODAY WHICH
WILL RESULT IN POSSIBLE MVFR CONDITIONS AT TIMES. MVFR TO IFR
CONDITIONS WILL ALSO BE POSSIBLE AT TIMES DUE TO LOW CEILINGS FROM
KMLS EASTWARD. GUSTY NORTHWEST WINDS WILL BE LIKELY FROM KBIL
EASTWARD BUT ESPECIALLY TOWARD KMLS TO THE DAKOTA BORDERS. HOOLEY
&&
.PRELIMINARY POINT TEMP/POPS...
TDY FRI SAT SUN MON TUE WED
-------------------------------------------------------
BIL 065 043/077 049/084 053/068 048/071 050/071 048/062
1/B 00/U 00/U 22/T 11/B 02/T 22/W
LVM 064 035/078 043/083 046/065 042/068 045/068 045/054
0/B 00/U 00/U 22/T 11/B 12/T 23/W
HDN 066 038/079 045/086 051/072 046/073 049/074 048/065
2/W 00/U 00/U 12/T 21/B 01/B 12/W
MLS 059 042/075 048/084 054/073 050/075 052/074 050/068
2/W 00/U 00/U 22/T 21/U 11/B 12/W
4BQ 062 038/075 045/084 053/075 047/074 049/075 047/068
1/B 00/U 00/U 12/T 21/U 11/U 12/W
BHK 056 037/072 044/080 050/075 047/073 048/074 047/069
2/W 00/U 00/U 12/T 21/U 11/U 12/W
SHR 063 036/076 046/084 050/070 044/071 047/072 045/064
1/B 00/U 00/U 12/T 30/U 01/U 12/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
251 AM CDT THU SEP 19 2013
.DISCUSSION...
GLANCE AT REGIONAL RADAR ALREADY SHOWING LINE OF CONVECTION FIRING
ALONG INTENSE SFC BAROCLINIC ZONE EXTENDING FROM ABOUT NRN MN TO
NWRN KS. BNDRY IN ASSOCIATION WITH UPPER SHORTWAVE TROF MIGRATING
ACROSS THE NRN PLAINS. AGEOSTROPHIC LIFT JUST AHEAD OF RELATIVELY
DEEP FRONTOGENESIS BNDRY IS QUITE STOUT...PER RUC13. ALSO...STRONG
UPPER LEVEL DIVG ASSOCIATE WITH RRQ OF JET MAX ALOFT CONTRIBUTING TO
ENHANCEMENT OF SYNOPTIC LIFT AS WELL.
SHORT TERM ISSUE IS TIMING THE FRONTAL PASSAGE/PCPN THRU THE CWA.
REGIONAL RADAR WAS SHOWING AN OUTFLOW BNDRY ASSOCIATED WITH CLUSTER
OF STORMS IN WRN NEB WAS QUICKLY PUSHING EAST...AND WILL PROBABLY
REACH THE CWA IN THE NEXT COUPLE HOURS. AT ANY RATE...SFC WIND PROGS
VIA TIME-SERIES INDICATE LEADING EDGE OF THE TRUE FRONT REACHING
KOFK BY LATE MORNING...THEN EARLY AFTN AT KLNK AND KOMA...THUS
APPROXIMATE TIME FRAME FOR FOR EXPECTED CONVECTION. MEANWHILE...
PERSISTENT MOISTURE ADV INTO THE REGION THE LAST 24 HRS HAS
CULMINATED IN A MOISTURE RICH ENVIRONMENT AS SEE BY PWS VALUES
RANGING ANYWHERE FROM 160%-220% ABOVE NORM AHEAD OF THE FRONT. AT
THIS POINT SUSPECT THAT PCPN INTENSITY WILL INCREASE THIS AFTN OVER
SRN CWA WHERE THE RUC13 IS SHOWING PRECIP EFFICIENCY/WARM CLOUD DEPTH
PEAKS. IMPROVING CONDITIONS THEN TONIGHT AS STABLE AIRMASS ENVELOPS
THE REGION. IN CASE OF LINGERING PCPN ACTIVITY...WILL MAINTAIN TOKEN
EVENING POPS SOUTH.
EXCELLENT WEATHER ON TAP THIS WEEKEND IN RESPONSE TO UPPER RIDGE
BUILDING OVER THE PLAINS.
NEXT ROUND OF PCPN COMES SUNDAY NIGHT/MONDAY WHEN NEXT POTENT
SHORTWAVE TROF EXITS THE ROCKIES AND SWEEPS ANOTHER COLD FRONT INTO
THE CNTRL PLAINS. WITH GFS AND ECM IN AGREEMENT DECENT LLVL
MOISTURE FEED PRECEDING THE FRONT...GENEROUS RAINFALL AMOUNTS WILL
ONCE AGAIN BE POSSIBLE.
DEE
&&
.AVIATION...06Z TAFS FOR KOFK...KOMA AND KLNK.
A COLD FRONT IS STILL ON TRACK TO CROSS TAF SITES THURSDAY WITH
SCATTERED SHOWERS AND THUNDERSTORMS MOSTLY ALONG OR BEHIND FRONT.
FIRST ROUND OF CONVECTION OVER WRN NEBR COULD MOVE ACROSS KOFK
VICINITY THURSDAY MORNING AND FORECAST WILL REFLECT THIS. ALTHOUGH
SOME OF THIS ACTIVITY COULD IMPACT KLNK AND KLNK...TSTMS WERE NOT
MENTIONED AT THOSE SITES UNTIL AFTERNOON WHEN ADDITIONAL
DEVELOPMENT IS EXPECTED AND CHANCES APPEARED HIGHER. THUS PROB30
GROUPS IN 00Z FORECAST WERE UPGRADED TO TEMPO GROUPS AT BOTH
KLNK AND KOMA. SHOWERS/ISOLD TSTMS COULD LINGER INTO EARLY
THURSDAY EVENING BEFORE MOVING TO THE EAST.
CHERMOK
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
1111 PM MDT WED SEP 18 2013
.AVIATION...
06Z TAF CYCLE
MTS OCCASIONALLY OBSCURED. ISOLD CONVECTION TO PERSIST AND MOVE
GENLY NORTHEAST TO EAST OVER NRN AND CENTRAL NM THROUGH THE
OVERNIGHT HOURS AS UPPER DISTURBANCE TRACKS EAST OVER THE REGION.
LOCALIZED MVFR CIGS/VSBYS IN TSRA WILL BE POSSIBLE ALONG WITH
SFC WND GUSTS TO 35KT. LOCAL MVFR CIGS POSSIBLE FROM THE CENTRAL
MT CHAIN ACROSS THE EASTERN PLAINS AFT 08Z TO AROUND 15Z THURSDAY.
SFC FRONT TO APPROACH FAR NE NM BY 15Z THURSDAY WITH SCT
CONVECTION DVLPG THEREAFTER FROM THE CENTRAL MT CHAIN TO THE TX
BORDER.
&&
.PREV DISCUSSION...256 PM MDT WED SEP 18 2013...
ANOTHER ACTIVE WX SCENARIO SHAPING UP OVER THE REGION FOR REMAINDER
OF TODAY THRU THURSDAY. CIRA LAYERED TOTAL PW PRODUCT SHOWS ABUNDANT
LOW/MID LEVEL MOISTURE ACROSS THE REGION WITH VERY DRY CONDITIONS
ALOFT. VALUES ARE ON THE ORDER OF 130-160 PCT OF NORMAL. A THIN 30-
50 KT UPPER JET AXIS OVER NM AS SEEN ON THE LATEST AMDAR DATA IS
INTERACTING WITH THE LOW LEVEL MOISTURE AND INSTABILITY TO PRODUCE
A WELL DEFINED BAND OF THUNDERSTORMS OVER WESTERN AND NORTHERN NM.
STEERING FLOWS ARE STRONG TODAY HOWEVER THE SHEAR AXIS IS ORIENTED
IN THE DRXN OF STORM MOTION SO MORE LOCALLY HEAVY RAINFALL ON TAP.
LATEST HRRR SHOWS THIS AREA OF SHOWERS AND STORMS PROPAGATING EVER
SO SLOWLY EAST THIS EVENING INTO THE RIO GRANDE VALLEY AND NEARBY
HIGH TERRAIN. HAVE RAISED POPS TO HIGH CHANCE AND LIKELY FOR CENTRAL
NM.
EVEN MORE ACTIVE CONDITIONS WILL TAKE SHAPE INTO THURSDAY NIGHT BUT
MORE INTO THE EASTERN PLAINS. A LARGE UPPER TROUGH OVER THE PACIFIC
NW WILL SLIDE EAST INTO THE GREAT PLAINS AND HELP DRIVE A SURFACE
BACK DOOR FRONTAL BOUNDARY INTO NM. MEANWHILE...A VERY WELL DEFINED
UPPER WAVE EMBEDDED ON THE BACK SIDE OF THE LARGE SCALE WAVE WILL
SLIDE OVER NORTHERN NM AND HELP LIFT FOCUS OVER FRONT. CURRENT QPF
VALUES ARE POTENTIALLY TOO LOW FOR THIS EVENT ACROSS THE EAST WHERE
SUBSTANTIALLY MOISTURE REMAINS IN PLACE. FLOODING IS NOT EXPECTED
HOWEVER SOME LOCALIZED IMPACTS ARE LIKELY IF THE RAIN FALLS OVER
THE WRONG SPOT. ALSO RAISED POPS FOR THE EASTERN PLAINS THURSDAY
NIGHT TO LIKELY. TEMPS THROUGH THIS PERIOD WILL COOL BELOW NORMAL
FOR MUCH OF THE REGION...ESPECIALLY THE EAST.
MODELS DO INDICATE STRONGER WESTERLIES AND DRIER AIR SHIFTING EAST
INTO THE STATE FRIDAY THRU SUNDAY HOWEVER STRONG MOISTURE RECYCLING
PROCESSES WILL STILL BE AT PLAY. LOW CLOUDS AND FOG ARE POSSIBLE
ANY NIGHT ESPECIALLY IF SKIES CLEAR AND WINDS TAPER OFF. TEMPS WILL
BE COOL OUT WEST WHERE MUCH DRIER DEWPOINTS WILL MOVE IN. THE
EXTENDED PATTERN IS STILL HIGHLY UNCERTAIN SO MADE NO CHANGES. THE
ECMWF PROGS A DEEP LARGE SCALE STATIONARY UPPER LOW OVER THE GREAT
BASIN WITH A RELATIVELY ABUNDANT MONSOONAL MOISTURE TAP OVER NM. THE
GFS HAS AN EVEN DEEPER TIGHTLY WOUND COLD UPPER LOW DRIVING EAST
ACROSS THE CENTRAL ROCKIES THRU MID WEEK.
GUYER
&&
.FIRE WEATHER...
SCATTERED WETTING THUNDERSTORMS FOUND ACROSS WESTERN AND NORTHERN
AREAS WILL TRANSITION EASTWARD THIS EVENING BEFORE DIMINISHING SOME.
DRIER AIR WILL EVENTUALLY FILL IN FROM WEST TO EAST LATER TONIGHT
AND WILL SET THE STAGE FOR A DRIER WESTERN AND CENTRAL AREAS ON
THURSDAY.
A BACK DOOR COLD FRONT IS STILL EXPECTED FOR THURSDAY WITH EASTERN
AREAS OBSERVING THAT INFLUENCE. THIS INCLUDES WETTING SHOWERS AND
THUNDERSTORMS WHICH WOULD FAVOR MOST OF THE EASTERN PLAINS THURSDAY
AFTERNOON INTO THE OVERNIGHT. MIXING HEIGHTS WILL INCREASE ACROSS
THE MAJORITY OF THE AREA ALTHOUGH TRANSPORT WINDS WILL COME DOWN
MOST AREAS SO VENTILATION RATES WILL LOWER PRETTY MUCH AREAWIDE.
THE BACK DOOR COLD FRONT WILL PUSH THROUGH THE CENTRAL MOUNTAINS
THURSDAY NIGHT AND MOST LIKELY MAKE IT TO THE AZ STATE LINE BY
FRIDAY MORNING. MIXING DURING FRIDAY AFTERNOON SHOULD SET UP A
CONVERGENCE BOUNDARY NEAR THE CONTINENTAL DIVIDE AND MOST LIKELY
PROVIDE A FOCUS FOR THUNDERSTORMS THERE. THE ATMOSPHERE COULD BE TOO
STABLE FOR SIGNIFICANT SHOWER AND THUNDERSTORM DEVELOPMENT ACROSS
CENTRAL AND EASTERN AREAS DUE TO RESIDUAL IMPACTS FROM THE COLD
FRONT. HUMIDITY VALUES WILL BE UNSEASONABLY HIGH FRIDAY AFTERNOON.
TEMPERATURES WILL BE COOLER THAN NORMAL CENTRAL AND EASTERN AREAS
WHILE BEING NEAR NORMAL WEST OF THE CONTINENTAL DIVIDE. VENTILATION
RATES WILL BE LOWEST EXTENDING FROM ZONE 109 NORTHEASTWARD OVER THE
MIDDLE RIO GRANDE VALLEY AND AREAS TO THE LEE OF THE SANGRE DE
CRISTOS.
THE NEXT PACIFIC TROUGH WILL PLUNGE INTO THE FAR WESTERN US SATURDAY
AND CONTINUE TO TRAVERSE ACROSS THE INTERMOUNTAIN WEST ON SUNDAY.
MOISTURE WILL TRY TO SEEP UP FROM MEXICO AHEAD OF THIS TROUGH SO
LOOK FOR UNSETTLED WEATHER ACROSS THE WEST ON SATURDAY TRANSITIONING
SOME EASTWARD ON SUNDAY. WETTING RAIN WOULD CERTAINLY BE POSSIBLE
ALTHOUGH NOT AS WIDESPREAD AS THE PREVIOUS WEEK. HUMIDITY IS
EXPECTED TO TREND UP ACROSS THE WEST ON SATURDAY WHILE LOWER ACROSS
THE EAST. ON SUNDAY...HUMIDITY IS EXPECTED TO LOWER AREAWIDE
ALTHOUGH THIS COULD CHANGE. VENTILATION WILL INCREASE DURING THE
WEEKEND THANKS TO STRONGER WEST/SOUTHWEST TRANSPORT WIND. CONFIDENCE
IS PRETTY GOOD THAT A PACIFIC TROUGH WILL IMPACT THE AREA BUT STILL
NOT TOTALLY SURE ABOUT HOW MUCH MOISTURE WILL SEEP UP FROM THE SOUTH
AND FEED THE TROUGH. SURFACE WIND SHOULD ALSO INCREASE DURING THE
WEEKEND PERIOD.
ANOTHER PACIFIC TROUGH IS EXPECTED TO AFFECT THE WESTERN US BY THE
MIDDLE OF NEXT WEEK. THE LONG RANGE MODELS DIFFER SOMEWHAT IN THE
EXTENSION SOUTHWARD OF THE TROUGH BUT EITHER WAY IMPACT POTENTIAL
WOULD INCREASE BY MID NEXT WEEK. DEPENDING ON HOW THE TROUGH COMES
IN...ADDITIONAL WETTING RAIN WOULD BE POSSIBLE. CONDITIONS FOLLOWING
THE TROUGH PASSAGE COULD LEAD TO THE MOUNTAINS FIRST BIG FREEZE OF
THE FALL SEASON SO WILL BE WATCHING THAT AS THAT WOULD BEGIN THE
CURING PROCESS TO THE ABUNDANT FUELS THAT HAVE GREENED UP THIS SUMMER.
50
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
401 AM EDT THU SEP 19 2013
.SYNOPSIS...
A SERIES OF UPPER LEVEL DISTURBANCES WILL RESULT IN A CHANCE OF
SHOWERS AND THUNDERSTORMS TODAY INTO TONIGHT. SHOWERS AND
THUNDERSTORMS WILL BECOME MORE WIDESPREAD FRIDAY AFTERNOON INTO
FRIDAY NIGHT AS A COLD FRONT APPROACHES FROM THE WEST. SHOWERS AND
A FEW THUNDERSTORMS WILL CONTINUE INTO SATURDAY BEFORE A DRIER AND
COOLER AIRMASS SETTLES INTO THE REGION FOR THE FIRST PART OF NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A PERSISTENT MCV HAS BEEN PROGRESSING VERY SLOWLY SOUTHEAST ACROSS
NORTHERN INDIANA THROUGH THE OVERNIGHT HOURS. SO FAR IT HAS NOT
SHOWED TOO MAY SIGNS OF DISSIPATING OR EVEN WEAKENING AND THE LAST SEVERAL
RUNS OF THE HRRR HAVE BEEN CONSISTENTLY TRYING TO PUSH IT
SOUTHEAST INTO OUR AREA THROUGH MID MORNING. THE AIRMASS ACROSS
OUR AREA IS MORE STABLE WITH THE INSTABILITY GRADIENT DROPPING OFF
FAIRLY QUICKLY ACROSS EASTERN INDIANA INTO WESTERN OHIO. AS A
RESULT..WOULD EXPECT THE BETTER CHANCE OF THUNDERSTORM MAINTENANCE
TO WORK MORE TO THE SOUTH AND STAY WEST OF MOST OF OUR AREA
THROUGH THE MORNING HOURS. HOWEVER...THE 850-300 MB MEAN WIND IS
MORE WESTERLY ACROSS NORTHERN INDIANA...BECOMING SOUTHEASTERLY
ACROSS OUR AREA. THIS WOULD SUGGEST A DECENT CHANCE THAT SOME OF
THE SHOWER ACTIVITY WILL WORK ITS WAY INTO AT LEAST THE WESTERN
HALF OF OUR FA OVER THE NEXT SEVERAL HOURS.
MEANWHILE...ABUNDANT LOW LEVEL MOISTURE ACROSS OUR AREA HAS ALLOWED
FOR SOME FAIRLY WIDESPREAD STRATUS DEVELOPMENT ACROSS ABOUT THE
SOUTHEAST TWO THIRDS OF OUR FA. WITH THE LOW LEVELS REMAINING MIXY
THROUGH DAYBREAK...WOULD NORMALLY NOT BE SURPRISED TO SEE THE
STRATUS EXPAND A LITTLE MORE...BUT THE DEBRIS CLOUDS FROM THE MCV
MAY MITIGATE THIS TO SOME DEGREE. EITHER WAY...THE COMBINATION OF
THE DEBRIS CLOUDS AND STRATUS DECK SHOULD KEEP US MAINLY CLOUD
THROUGH THE MORNING HOURS. THIS MAY ALSO HAVE AN IMPACT ON
TEMPERATURES AND HOW WELL WE DESTABILIZE THROUGH THIS AFTERNOON. IN
THE WESTERLY TO SOUTHWESTERLY LOW LEVEL WAA PATTERN...WOULD EXPECT
TO SEE SOME DECENT EROSION/DISSIPATION OF THE LOWER CLOUDS
THROUGH LATE MORNING/EARLY AFTERNOON WHICH SHOULD EVENTUALLY ALLOW
FOR PARTLY SUNNY SKIES. WILL NUDGE DOWN HIGHS JUST A TAD...GENERALLY
RANGING FROM UPPER 70S EAST TO LOWER 80S WEST. THIS WOULD STILL
ALLOW US TO DESTABILIZE THROUGH THIS AFTERNOON WITH ML CAPES PUSHING
UP CLOSE TO 1000 J/KG. AS A RESULT...WILL GO AHEAD AND ALLOW FOR
SOME CHANCE POPS ACROSS MUCH OF THE AREA THROUGH THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
THE 00Z NAM/GFS AND CMC ARE ALL TRYING TO HINT AT SOME SORT OF
CONTINUING PCPN OR REDEVELOPMENT TONIGHT SOMEWHERE ACROSS OUR AREA
WHILE THE 00Z ECMWF IS DRY. IT DOES LOOK LIKE WE COULD BE ON THE
EDGE OF A SOUTHWEST TO NORTHEAST ORIENTED 925-850 MB LOW LEVEL
JET LATER TONIGHT AND THIS COULD SERVE AS A FOCUSING MECHANISM.
AS A RESULT..WILL HANG ON TO SOME LOWER END POPS...BUT CONFIDENCE
IS NOT ALL THAT HIGH.
A COLD FRONT WILL MOVE ACROSS THE AREA FRIDAY NIGHT. AHEAD OF
THIS...WE SHOULD WARM UP FAIRLY WELL THROUGH THE DAY WITH HIGHS
PUSHING UP INTO THE LOW TO MID 80S. THIS WILL ALLOW US TO
DESTABILIZE ONCE AGAIN WITH MLCAPES AGAIN UP CLOSE TO 1000 J/KG.
THIS SHOULD LEAD TO SOME SCATTERED PRE FRONTAL SHOWERS AND
THUNDERSTORMS THROUGH THE DAY. BETTER LOW LEVEL CONVERGENCE JUST
AHEAD OF THE FRONT WILL PUSH INTO OUR NORTHWEST LATE FRIDAY
AFTERNOON AND THEN PROGRESS SOUTHEAST ACROSS OUR AREA THROUGH FRIDAY
EVENING. THIS WILL ALLOW FOR A MORE ORGANIZED LINE OF SHOWERS AND
THUNDERSTORMS. DEEP LAYER SHEAR IS NOT TERRIBLY STRONG INITIALLY WITH
THE PCPN FRIDAY AFTERNOON/FRIDAY EVENING...BUT THE 0-3 KM SHEAR
VALUES DO PUSH UP INTO THE 25 TO 30 KNOT RANGE. THIS MAY BE
ENOUGH TO SUPPORT SOME MARGINALLY SEVERE STORMS LATE FRIDAY
AFTERNOON INTO FRIDAY EVENING....ESPECIALLY ACROSS OUR NORTHWEST.
AS THE FRONT PUSHES OFF TO THE SOUTHEAST...EXPECT PCPN TO TAPER
OFF FROM NORTHWEST TO SOUTHEAST DURING THE DAY ON SATURDAY.
HIGH PRESSURE AND A COOLER AIRMASS WILL BUILD INTO THE AREA THROUGH
THE LATER PART OF THE WEEKEND. HIGHS ON SATURDAY WILL BE IN THE 70-75
DEGREE RANGE WITH HIGHS ON SUNDAY IN THE UPPER 60S TO NEAR 70.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
ON MONDAY...HIGH PRESSURE WILL BUILD IN FROM THE NORTH. COULD SEE
ENOUGH MOISTURE FROM THE LOW MOVING UP THE COAST TO PRODUCE
ISOLATED SHOWERS IN THE EXTREME EAST. AFTER MONDAY...SURFACE HIGH
PRESSURE EXTENDING INTO THE REGION FROM THE NE WILL BRING DRY
WEATHER AND MILD TEMPERATURES.
&&
.AVIATION /07Z THURSDAY THROUGH MONDAY/...
SLIGHTLY UNSETTLED WEATHER CONDITIONS WILL CONTINUE THROUGH THE
NEXT SEVERAL DAYS. MOISTURE CONTINUES TO INCREASE OVER THE OHIO
VALLEY...RESULTING IN INCREASING CLOUDS...AND SHOWERS.
THE BIGGEST CONCERN THIS MORNING IS THE POTENTIAL FOR STRATUS
DEVELOPMENT. THERE IS HIGH CONFIDENCE IN A THICKENING OF THE LOW-
LEVEL MOISTURE OVERNIGHT...WITH UPSTREAM CONDITIONS ALREADY
INDICATING MVFR CEILINGS ACROSS MUCH OF KENTUCKY AND IFR CIGS
ACROSS MUCH OF THE EASTERN HALF OF OHIO. THESE CLOUDS ARE EXPECTED
TO LOWER AS THEY OVERSPREAD THE TAF SITES. THIS WILL MAKE THE FOG
FORECAST SOMEWHAT MORE DIFFICULT BECAUSE THE STRATUS SHOULD KEEP
THE VSBYS FROM LOWERING TO LIFR MOST AREAS. BOTTOM LINE IS THAT A
BLANKET OF IFR CONDITIONS ARE EXPECTED TO DEVELOP ACROSS THE
ENTIRE FORECAST AREA OVER THE NEXT FEW HOURS. CEILINGS WILL BE SLOW
TO LIFT ON THURSDAY...AS SHOWERS AND LARGE PATCHES OF LATE RAIN
OVER SPREAD THE AREA AFTER 09Z ASSOCIATED WITH A SMALL
THUNDERSTORM COMPLEX OVER NORTHERN INDIANA MOVING TOWARDS THE
SOUTHEAST. WHILE THERE IS A RISK OF THUNDER AS THE PRECIPITATION
MOVES IN THIS MORNING...IT IS NOT HIGH ENOUGH TO PUT INTO THE
FORECAST AT THIS TIME. SHOWERS AND LOW CLOUDS WITH MVFR
CONDITIONS ARE EXPECTED TO LAST INTO THE MID AFTERNOON HOURS.
OUTLOOK...THUNDERSTORMS WILL BE POSSIBLE FROM FRIDAY AFTERNOON
THROUGH SATURDAY MORNING.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...JGL
NEAR TERM...JGL
SHORT TERM...JGL
LONG TERM...PARKER
AVIATION...HATZOS/HAYDU
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
118 AM EDT THU SEP 19 2013
.SYNOPSIS...
AN INCREASE IN MOISTURE AND A SERIES OF WEAK UPPER LEVEL
DISTURBANCES WILL RESULT IN A CHANCE OF SHOWERS AND A FEW THUNDERSTORMS
TO THE REGION TONIGHT AND THURSDAY. A BETTER CHANCE OF THUNDERSTORMS
WILL DEVELOP FRIDAY AFTERNOON INTO FRIDAY NIGHT AS A COLD FRONT
MOVES ACROSS THE AREA FROM THE NORTHWEST.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
THERE ARE CONCERNS ON BOTH SIDES OF THE CWA TONIGHT...REQUIRING A
FEW CHANGES TO THE GRIDS.
IN THE EASTERN CWA...A LARGE EXPANSE OF STRATUS HAS DEVELOPED. AS
ADDITIONAL MOISTURE MOVES NORTH INTO THE CWA...THIS IS EXPECTED TO
CONTINUE THROUGH THE NIGHT...WITH CEILINGS LOWERING. SKY GRIDS
HAVE BEEN ADJUSTED...THOUGH IT WAS NOT QUITE POSSIBLE TO INCREASE
TO 100 PERCENT WHEN MOST OF THE CWA STILL IS MOSTLY CLEAR...OR
EVEN BROKEN ON THE EDGES OF THE STRATUS. HOWEVER...THE FAR EASTERN
CWA SHOULD REMAIN CLOUDY THROUGH THE NIGHT.
ATTENTION IS ALSO TURNING TO CONVECTION NEAR CHICAGO...WHICH
SEVERAL RUNS OF THE HRRR AND RAP INDICATE WILL MAKE IT INTO THE
NORTHWEST CWA BY THE EARLY MORNING HOURS. THERE IS A GRADIENT OF
ELEVATED INSTABILITY THAT WILL SHIFT GRADUALLY EAST THROUGH THE
NIGHT...ALLOWING A TRAJECTORY (IF THE CONVECTION HOLDS TOGETHER)
THAT WOULD EVENTUALLY MOVE THROUGH INDIANA AND INTO THE ILN
FORECAST AREA. POPS HAVE BEEN INCREASED IN THE NORTHWESTERN CWA
WITH THUNDER INTRODUCED. TIMING THE CONVECTION OUT WOULD HAVE IT
INTO THE MERCER/WAYNE COUNTY AREAS BY 07Z...AND FURTHER FORECAST
UPDATES WILL BE NECESSARY IF THIS LOOKS MORE LIKELY TO OCCUR.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/...
ISENTROPIC LIFT DEVELOPS ACROSS THE AREA THURSDAY WITH WARM FRONT
LIFTING NORTHEAST INTO THE GREAT LAKES. WILL CONTINUE CHANCE POPS
WITH THE BEST THREAT ACRS THE NW WHERE MOST FAVORABLE INSTBY WILL
EXIST. IN WARM AIR ADVECTION PATTERN EXPECT TEMPERATURES TO RUN
AROUND 5 DEGREES ABOVE NORMAL...WITH HIGHS RANGING FROM NEAR 80 NE
TO THE MID 80S SW.
WITH THE PASSAGE OF THE WARM FRONT AND RIDGING IN MID LEVELS THERE
WILL BE A LACK OF SIGNIFICANT FORCING THURSDAY NIGHT. HAVE DIMINISHED
POPS FROM THE SOUTH WITH A SLIGHT CHANCE EARLY TO DRY OVERNIGHT.
SRLY SFC WINDS WILL STAY UP AT 5 TO 10 MPH ALONG WITH CLOUD COVER
WILL KEEP TEMPERATURES ON THE WARMER SIDE. EXPECT OVERNIGHT LOWS
TO RANGE FROM THE MID 60S SE TO THE UPPER 60S NW.
PROGRESSIVE/DIGGING MID LEVEL TROF TO MOVE INTO THE WESTERN GREAT
LAKES/UPR MS VLY FRIDAY AND THE GREAT LAKES FRIDAY NIGHT.
ASSOCIATED SFC COLD FRONT TO PUSH EAST THRU ILN/S FA FRIDAY
NIGHT/EARLY SATURDAY. NAM SOLN IS DEPICTING A PRE-FRONTAL TROF
WITH MODERATE INSTBY INTO THE WEST LATE FRIDAY AFTN. GIVEN THE
HIGHER RESOLUTION THIS LOOKS REASONABLE. WILL CONTINUE TO RAMP UP
POPS TO LKLY LATE IN THE DAY FRIDAY AND THEN CATEGORICAL FRIDAY
NIGHT ACRS THE ENTIRE REGION AS THE FRONT PUSHES IN. WILL CONTINUE
TO HIGHLIGHT POTENTIAL FOR LOCALLY DAMAGING WINDS AND SOME HAIL
WITH SOME OF THE STRONGER STORMS FRIDAY AFTN/EARLY EVENING. THIS
WILL BE DEPENDENT ON INSTBY AND WILL LIMIT AREAL EXTENT TO OVER
THE WESTERN COUNTIES. GIVEN WAA AHEAD OF THE FRONT...EXPECT TEMPS
TO BE CLOSE TO 10 DEGREES ABOVE NORMAL WITH HIGHS ON FRIDAY
RANGING FROM THE MID/UPR 80S SE TO THE LOWER 80S FAR NW.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
A COLD FRONT IS EXPECTED TO BE LOCATED THROUGH THE EASTERN PARTS OF
THE FA SATURDAY MORNING. SHOWERS AND SOME THUNDERSTORMS WILL LINGER
BEHIND THE FRONT ON SATURDAY AS THE UPPER TROUGH SWINGS THROUGH THE
OHIO RIVER VALLEY REGION. WIDELY SCATTERED SHOWERS MAY LINGER IN THE
SE ON SUNDAY. LATEST ECMWF IS MORE PROGRESSIVE WITH THE FRONT AND
FUTURE FORECASTS MAY NEED TO CUT BACK ON PRECIPITATION SATURDAY
AFTERNOON AND SUNDAY. ON MONDAY...HIGH PRESSURE WILL BUILD IN FROM
THE NORTH. COULD SEE ENOUGH MOISTURE FROM THE LOW MOVING UP THE
COAST TO PRODUCE ISOLATED SHOWERS IN THE EXTREME EAST. AFTER
MONDAY...SURFACE HIGH PRESSURE EXTENDING INTO THE REGION FROM THE
NE WILL BRING DRY WEATHER AND MILD TEMPERATURES.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
SLIGHTLY UNSETTLED WEATHER CONDITIONS WILL CONTINUE THROUGH THE
NEXT SEVERAL DAYS. MOISTURE CONTINUES TO INCREASE OVER THE OHIO
VALLEY...RESULTING IN INCREASING CLOUDS...AND SHOWERS.
THE BIGGEST CONCERN THIS MORNING IS THE POTENTIAL FOR STRATUS
DEVELOPMENT. THERE IS HIGH CONFIDENCE IN A THICKENING OF THE LOW-
LEVEL MOISTURE OVERNIGHT...WITH UPSTREAM CONDITIONS ALREADY
INDICATING MVFR CEILINGS ACROSS MUCH OF KENTUCKY AND IFR CIGS
ACROSS MUCH OF THE EASTERN HALF OF OHIO. THESE CLOUDS ARE EXPECTED
TO LOWER AS THEY OVERSPREAD THE TAF SITES. THIS WILL MAKE THE FOG
FORECAST SOMEWHAT MORE DIFFICULT BECAUSE THE STRATUS SHOULD KEEP
THE VSBYS FROM LOWERING TO LIFR MOST AREAS. BOTTOM LINE IS THAT A
BLANKET OF IFR CONDITIONS ARE EXPECTED TO DEVELOP ACROSS THE
ENTIRE FORECAST AREA OVER THE NEXT FEW HOURS. CEILINGS WILL BE SLOW
TO LIFT ON THURSDAY...AS SHOWERS AND LARGE PATCHES OF LATE RAIN
OVER SPREAD THE AREA AFTER 09Z ASSOCIATED WITH A SMALL
THUNDERSTORM COMPLEX OVER NORTHERN INDIANA MOVING TOWARDS THE
SOUTHEAST. WHILE THERE IS A RISK OF THUNDER AS THE PRECIPITATION
MOVES IN THIS MORNING...IT IS NOT HIGH ENOUGH TO PUT INTO THE
FORECAST AT THIS TIME. SHOWERS AND LOW CLOUDS WITH MVFR
CONDITIONS ARE EXPECTED TO LAST INTO THE MID AFTERNOON HOURS.
OUTLOOK...THUNDERSTORMS WILL BE POSSIBLE FROM FRIDAY AFTERNOON
THROUGH SATURDAY MORNING.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...AR
NEAR TERM...HATZOS
SHORT TERM...AR
LONG TERM...PARKER
AVIATION...HAYDU
Area Forecast Discussion
National Weather Service Lincoln IL
1040 AM CDT Thu Sep 19 2013
.DISCUSSION...
ISSUED 1040 AM CDT Thu Sep 19 2013
Warm front has lifted well to the northeast of central Illinois
this morning, leaving behind partly to mostly sunny skies and very
warm temps in the upper 70s and lower 80s. Convection continues to
fire along the edge of the strengthening cap in the warm sector,
mainly from southern Lake Michigan S/SE across Indiana into the
Ohio River Valley. As warm air aloft spreads further east, this
activity will continue to shift further away from Illinois this
afternoon. End result will be a hot and mainly dry day, with
perhaps a few isolated thunderstorms. Afternoon high temps will
reach the upper 80s and lower 90s. Better thunderstorm chances
will arrive by late evening across the Illinois River Valley.
Latest HRRR shows a line of convection developing along an
advancing cold front and pushing toward the Illinois River by
around 03z. This activity should continue eastward in a weakening
state overnight.
Barnes
&&
.AVIATION...
ISSUED 655 AM CDT Thu Sep 19 2013
An area of showers and thunderstorms associated with a small MCS will
mainly stay east of the central IL terminal airports this morning
from Vermilion county ese into Indiana. Carried VCSH over eastern
IL airports til 14-15Z with light fog/haze bringing visibilities
of 4-6 miles. Isolated convection possible this afternoon and
early evening as airmass become more unstable, but coverage too
limited to pinpoint down in the TAFs. VFR conditions should
generally prevail today and this evening with scattered cumulus
clouds and scattered-broken mid level clouds. A cold front
extending from 1001 mb low pressure over se part of Lake Winnipeg
through western MN thru far nw corner of IA into se Nebraska and
nw KS. Cold front slated to push se to near the IL river by PIA
around 12Z/7 am Fri. A band of showers and thunderstorms to
accompany the cold front and spread se across central IL
overnight, reaching PIA after 05Z/midnight and DEC and CMI after
09Z/4 am. MVFR ceilings and visibilities possible with convection
overnight. SSW winds around 10 kts early this morning to increase
to 10-15 kts with gusts 18-23 kts by 15Z and continue through
early evening, then be 10-14 kts tonight and gradually veer sw
overnight.
07
&&
.PREV DISCUSSION...
ISSUED 251 AM CDT Thu Sep 19 2013
Developing storm system over the northern Plains to be the main
issue for the forecast in the Midwest for this package. High
pressure over the Atlantic seaboard slowly sliding eastward with
southerly flow ramping up over the region in the middle of the
country. Sunshine and WAA will send temperatures well above normal
ahead of the storm system. All the warm air in place will provide
instability for advancing chances of thunderstorms through tonight
and tomorrow. Biggest issues for the forecast revolve around the
timing of the front vs. max heating, and speed of the front
itself. Ongoing convection already starting to hint that the
mesoscale influences with prefrontal trofs and outflow boundaries
will more than likely complicate the forecast of the details. Best
chances for precip tonight and through tomorrow.
SHORT TERM...Today and tomorrow...
Hot today with the ridge expanding into the Midwest. Warmest
midlevels in western CWA but will likely be countered somewhat by
advancing clouds. However, front will hold off enough to see upper
80s over majority of the area. Cold front has slowed progression
to tomorrow but convection ahead of the front and associated cold
pools will mask some of the distinction of the leading edge.
Plenty of instability in the region...but the cold front being
delayed a bit results in the FA barely clipped by the slight risk
outlook to the northwest for tonight. Frontal progression tomorrow
to be slower, and already in rain and cloud cover from the overnight
will likely inhibit intense storm development. So far tomorrow
remains in a general thunder. Overnight Friday will see a clearing
from west to east. Will need to keep an eye on guidance NW of
Interstate 55 corridor for rapid clearing may result in a need for
an adjustment of the lows down a couple degrees.
LONG TERM...Saturday through Wednesday...
Milder weather and dry through the extended. High pressure
dominates the eastern half of the country and temperatures remain
milder and closer to normal...with heat building again under a
thermal ridge in the southwestern US. With southwesterly flow
kicking in next week Tues, the extended could see some warmer
temps as time draws nearer should the pattern persist. Guidance
is still being pulled to 70s by climatology at this point.
HJS
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1045 AM EDT THU SEP 19 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 355 AM EDT THU SEP 19 2013
AN UPPER RIDGE WILL BE ACROSS CENTRAL INDIANA THROUGH THIS EVENING
AS WARM MOIST AND UNSTABLE AIR MOVES IN FROM THE SOUTH ON THE BACK
SIDE OF SURFACE HIGH PRESSURE ACROSS THE EASTERN STATES. THERE IS A
CHANCE OF THUNDERSTORMS MAINLY THIS AFTERNOON AND EVENING AS WEAK
WAVES MOVE OVERTOP THE RIDGE AND THE ATMOSPHERE BECOMES VERY
UNSTABLE. THUNDERSTORMS WILL BECOME WIDESPREAD FRIDAY AND FRIDAY
NIGHT AS A COLD FRONT DROPS SOUTHEAST ACROSS CENTRAL INDIANA FRIDAY
NIGHT. THERE COULD BE A FEW LINGERING MORNING THUNDERSTORMS SATURDAY
MORNING ACROSS SOUTHEASTERN PARTS OF CENTRAL INDIANA.
OTHERWISE...HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT ALLOW FOR
COOLER TEMPERATURES AND DRY WEATHER THROUGH THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /REST OF TODAY AND TONIGHT/...
ISSUED AT 1008 AM EDT THU SEP 19 2013
.UPDATE...
NUMEROUS SHOWERS AND THUNDERSTORMS WILL LAST THROUGH MIDDAY AND...
AND INTO EARLY AFTERNOON OVER EASTERN SECTIONS OF THE REGION. RAPID
REFRESH THIS CONVECTION UNTIL MID AFTERNOON OVER THE EAST. AFTER
THAT WILL CONTINUE WITH THE SCENARIO THAT THUNDERSTORMS WILL DIMINISH
BY LATE AFTERNOON PER NAM AND RAPID REFRESH MODELS. IN REGARDS TO
TEMPERATURES LATEST RAP INDICATES HIGH TEMPERATURES APPROACHING 90
FAR WEST WHERE THERE WILL BE MORE SUNSHINE THIS AFTERNOON TO RAISE
TEMPERATURES. OVER THE EAST CLOUDS AND LINGERING PRECIPITATION MAY
KEEP HIGH TEMPERATURES CLOSER TO 80.
NO CHANGES WILL BE MADE AT THIS TIME TONIGHT. NAM SUGGESTS INDICATES
THERE SHOULD BE A LULL IN ANY THUNDERSTORM ACTIVITY MOST OF TONIGHT
AND THEN CHANCES INCREASING TOWARDS DAYBREAK WEST AS COLD FRONT
APPROACHES.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
ISSUED AT 355 AM EDT THU SEP 19 2013
MAIN CHALLENGE TO THE SHORT TERM WILL CONTINUE TO BE POPS ALONG WITH
TIMING OF SHOWER ACTIVITY OUT OF THE FORECAST AREA. MODELS ARE NOW
IN GOOD AGREEMENT ON FRONTAL TIMING AND WILL GO WITH A BLEND THAT
SUGGESTS THE APPROACHING STRONG NORTHERN UPPER TROUGH WILL FORCE THE
FRONT TO NEAR LAFAYETTE BY 00Z SATURDAY AND THEN SOUTHEAST OF
CENTRAL INDIANA AFTER 09Z SATURDAY. THE SPC DAY2 OUTLOOK AS THROWN
ROUGHLY OUR SOUTHEASTERN HALF OF THE FORECAST IN A SLIGHT RISK OF
SEVERE WEATHER FOR FRIDAY AFTERNOON AND EVENING. THIS SEEMS
REASONABLE AS THE LOW LEVEL JET WILL BE OVER THIS AREA AFTER 18Z
FRIDAY...AND WITH PLENTY OF WIDESPREAD ACTIVITY EXPECTED ACROSS THE
NORTHWEST HALF OF THE FORECAST AREA DURING THE MORNING AND
AFTERNOON...THAT PART OF THE FORECAST AREA WILL HAVE A HARD TIME
DESTABILIZING AS MUCH AS THE SOUTHEAST. EVEN SOUTHEAST...ONLY
EXPECT AN ISOLATED SEVERE STORM OR TWO WITH MARGINAL SHEAR AND
INSTABILITY. WILL GO WITH OCCASIONAL POPS FRIDAY SPREADING SOUTHEAST
DURING THE AFTERNOON AND NIGHT. WILL LEAVE SMALL CHANCE LINGER
SHOWERS SATURDAY MORNING...OTHERWISE...HIGH PRESSURE WILL BUILD IN
BEHIND THE FRONT WHICH WILL BRING DRY WEATHER IN FOR THE REST OF THE
WEEKEND ALONG WITH COOLER TEMPERATURES PER MOS AND MODEL BLEND.
HEAVY RAIN WILL CONTINUE TO BE A THREAT THROUGH FRIDAY NIGHT WITH
PRECIPITABLE WATER VALUES NOT DROPPING MUCH UNTIL OVERNIGHT FRIDAY
NIGHT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
ISSUED AT 355 AM EDT THU SEP 19 2013
DRY FORECAST THIS PERIOD WITH SEASONABLE TEMPERATURES.
GFS AND ECMWF DEPICT A CUT OFF UPPER LOW MOVING THROUGH THE
APPALACHIANS EARLY IN THE PERIOD WHILE RIDGING ALOFT AND STRONG
SUBSIDENCE OVER THE MISSISSIPPI RIVER VALLEY PROVIDES A NORTHERLY
FLOW OF AIR AS IT SLOWLY BUILDS EAST DURING THE PERIOD.
AS THE RIDGE MOVES EAST OVER INDIANA BY THE MIDDLE OF NEXT
WEEK...TEMPS WILL SLOWLY MODERATE TO SLIGHTLY ABOVE NORMAL AS
RETURN FLOW BEGINS.
&&
.AVIATION /DISCUSSION FOR THE 191500Z TAF UPDATE/...
ISSUED AT 1045 AM EDT THU SEP 19 2013
RADAR LOOP SHOWS AREAS OF THUNDERSTORMS WEST OF KIND AND AROUND AND
SOUTH AND SOUTHEAST OF KBMG. THINK CONVECTIVE THREAT WILL REMAIN
RATHER HIGH ACROSS THESE TAF SITES UNTIL THIS WAVE PASSES BY AROUND
191700Z OR SO WITH CONVECTIVE THREAT EAST OF KHUF AND KLAF. BRIEF
IFR VISIBILITY/CEILING RESTRICTIONS IN THE HEAVIER SHOWERS.
OTHERWISE...AREAS OF CEILINGS AROUND 020-025 EXPECTED THIS MORNING
AS WELL...ESPECIALLY AT KLAF/KIND...WITH CEILINGS GRADUALLY LIFTING
INTO A HIGHER DECK BY THIS AFTERNOON AS WAVE PULLS OFF TO THE EAST.
OUTSIDE OF ANY CONVECTION...SURFACE WINDS GENERALLY AROUND 10 KTS OR
LESS TODAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MK
NEAR TERM...JH
SHORT TERM...MK
LONG TERM....JAS
AVIATION...JAS/CP
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1008 AM EDT THU SEP 19 2013
.UPDATE...
NEAR TERM FOR THE REST OF TODAY HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 355 AM EDT THU SEP 19 2013
AN UPPER RIDGE WILL BE ACROSS CENTRAL INDIANA THROUGH THIS EVENING
AS WARM MOIST AND UNSTABLE AIR MOVES IN FROM THE SOUTH ON THE BACK
SIDE OF SURFACE HIGH PRESSURE ACROSS THE EASTERN STATES. THERE IS A
CHANCE OF THUNDERSTORMS MAINLY THIS AFTERNOON AND EVENING AS WEAK
WAVES MOVE OVERTOP THE RIDGE AND THE ATMOSPHERE BECOMES VERY
UNSTABLE. THUNDERSTORMS WILL BECOME WIDESPREAD FRIDAY AND FRIDAY
NIGHT AS A COLD FRONT DROPS SOUTHEAST ACROSS CENTRAL INDIANA FRIDAY
NIGHT. THERE COULD BE A FEW LINGERING MORNING THUNDERSTORMS SATURDAY
MORNING ACROSS SOUTHEASTERN PARTS OF CENTRAL INDIANA.
OTHERWISE...HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT ALLOW FOR
COOLER TEMPERATURES AND DRY WEATHER THROUGH THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /REST OF TODAY AND TONIGHT/...
ISSUED AT 1008 AM EDT THU SEP 19 2013
.UPDATE...
NUMEROUS SHOWERS AND THUNDERSTORMS WILL LAST THROUGH MIDDAY AND...
AND INTO EARLY AFTERNOON OVER EASTERN SECTIONS OF THE REGION. RAPID
REFRESH THIS CONVECTION UNTIL MID AFTERNOON OVER THE EAST. AFTER
THAT WILL CONTINUE WITH THE SCENARIO THAT THUNDERSTORMS WILL DIMINISH
BY LATE AFTERNOON PER NAM AND RAPID REFRESH MODELS. IN REGARDS TO
TEMPERATURES LATEST RAP INDICATES HIGH TEMPERATURES APPROACHING 90
FAR WEST WHERE THERE WILL BE MORE SUNSHINE THIS AFTERNOON TO RAISE
TEMPERATURES. OVER THE EAST CLOUDS AND LINGERING PRECIPITATION MAY
KEEP HIGH TEMPERATURES CLOSER TO 80.
NO CHANGES WILL BE MADE AT THIS TIME TONIGHT. NAM SUGGESTS INDICATES
THERE SHOULD BE A LULL IN ANY THUNDERSTORM ACTIVITY MOST OF TONIGHT
AND THEN CHANCES INCREASING TOWARDS DAYBREAK WEST AS COLD FRONT
APPROACHES.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
ISSUED AT 355 AM EDT THU SEP 19 2013
MAIN CHALLENGE TO THE SHORT TERM WILL CONTINUE TO BE POPS ALONG WITH
TIMING OF SHOWER ACTIVITY OUT OF THE FORECAST AREA. MODELS ARE NOW
IN GOOD AGREEMENT ON FRONTAL TIMING AND WILL GO WITH A BLEND THAT
SUGGESTS THE APPROACHING STRONG NORTHERN UPPER TROUGH WILL FORCE THE
FRONT TO NEAR LAFAYETTE BY 00Z SATURDAY AND THEN SOUTHEAST OF
CENTRAL INDIANA AFTER 09Z SATURDAY. THE SPC DAY2 OUTLOOK AS THROWN
ROUGHLY OUR SOUTHEASTERN HALF OF THE FORECAST IN A SLIGHT RISK OF
SEVERE WEATHER FOR FRIDAY AFTERNOON AND EVENING. THIS SEEMS
REASONABLE AS THE LOW LEVEL JET WILL BE OVER THIS AREA AFTER 18Z
FRIDAY...AND WITH PLENTY OF WIDESPREAD ACTIVITY EXPECTED ACROSS THE
NORTHWEST HALF OF THE FORECAST AREA DURING THE MORNING AND
AFTERNOON...THAT PART OF THE FORECAST AREA WILL HAVE A HARD TIME
DESTABILIZING AS MUCH AS THE SOUTHEAST. EVEN SOUTHEAST...ONLY
EXPECT AN ISOLATED SEVERE STORM OR TWO WITH MARGINAL SHEAR AND
INSTABILITY. WILL GO WITH OCCASIONAL POPS FRIDAY SPREADING SOUTHEAST
DURING THE AFTERNOON AND NIGHT. WILL LEAVE SMALL CHANCE LINGER
SHOWERS SATURDAY MORNING...OTHERWISE...HIGH PRESSURE WILL BUILD IN
BEHIND THE FRONT WHICH WILL BRING DRY WEATHER IN FOR THE REST OF THE
WEEKEND ALONG WITH COOLER TEMPERATURES PER MOS AND MODEL BLEND.
HEAVY RAIN WILL CONTINUE TO BE A THREAT THROUGH FRIDAY NIGHT WITH
PRECIPITABLE WATER VALUES NOT DROPPING MUCH UNTIL OVERNIGHT FRIDAY
NIGHT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
ISSUED AT 355 AM EDT THU SEP 19 2013
DRY FORECAST THIS PERIOD WITH SEASONABLE TEMPERATURES.
GFS AND ECMWF DEPICT A CUT OFF UPPER LOW MOVING THROUGH THE
APPALACHIANS EARLY IN THE PERIOD WHILE RIDGING ALOFT AND STRONG
SUBSIDENCE OVER THE MISSISSIPPI RIVER VALLEY PROVIDES A NORTHERLY
FLOW OF AIR AS IT SLOWLY BUILDS EAST DURING THE PERIOD.
AS THE RIDGE MOVES EAST OVER INDIANA BY THE MIDDLE OF NEXT
WEEK...TEMPS WILL SLOWLY MODERATE TO SLIGHTLY ABOVE NORMAL AS
RETURN FLOW BEGINS.
&&
.AVIATION /DISCUSSION FOR THE 191200Z TAFS/...
ISSUED AT 725 AM EDT THU SEP 19 2013
ORGANIZED AREA OF CONVECTION CONTINUES TO DROP SOUTHEAST ACROSS THE
CENTRAL SECTIONS OF THE FORECAST AREA...AIDED BY A 25-30KT LOW LEVEL
JET. BASED ON ITS MOVEMENT...APPEARS IT SHOULD BE OUT OF THE KIND
VICINITY BY OR SHORTLY AFTER ISSUANCE TIME. ADDITIONAL CONVECTION
DEVELOPING BEHIND THIS AREA AHEAD OF AN UPPER WAVE CURRENTLY MOVING
THROUGH EASTERN ILLINOIS. THINK CONVECTIVE THREAT WILL REMAIN RATHER
HIGH ACROSS THE TAF SITES UNTIL THIS WAVE PASSES BY AROUND 191700Z
OR SO. BRIEF IFR VISIBILITY RESTRICTIONS IN THE HEAVIER SHOWERS.
OTHERWISE...SOME MVFR VISIBILITY RESTRICTIONS IN LIGHT FOG EXPECTED
TO LIFT BY THE MID MORNING HOURS. AREAS OF CEILINGS AROUND 020-025
EXPECTED THIS MORNING AS WELL...ESPECIALLY AT KLAF/KIND...WITH
CEILINGS GRADUALLY LIFTING INTO A HIGHER DECK BY THIS AFTERNOON AS
WAVE PULLS OFF TO THE EAST.
OUTSIDE OF ANY CONVECTION...SURFACE WINDS GENERALLY AROUND 10 KTS OR
LESS TODAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MK
NEAR TERM...JH
SHORT TERM...MK
LONG TERM....JAS
AVIATION...JAS
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
921 AM MDT THU SEP 19 2013
.UPDATE...
ISSUED AT 909 AM MDT THU SEP 19 2013
AREA OF PRECIPITATION CONTINUES TO MARCH EAST AHEAD OF A COLD
FRONT THAT HAS MOVED THROUGH THE WEST HALF OF THE AREA SO FAR.
BEST CHANCES FOR RAINFALL CONTINUE TO LOOK TO BE OVER THE FAR EAST
AS LIFT FROM THE COLD FRONT COMBINED WITH AN UPPER LEVEL TROUGH
WILL MOVE THROUGH AROUND NOON. BEHIND THE FRONT NORTHERLY WINDS
HAVE BECOME GUSTY...RANGING FROM 20-30 MPH WITH SOME GUSTS NEARING
40 MPH IN FAR NORTHEAST COLORADO. THE GUSTS SHOULD START TO
DECLINE BY THE EARLY AFTERNOON AS THE SURFACE PRESSURE GRADIENT
BEHIND THE FRONT SLACKENS.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 358 AM MDT THU SEP 19 2013
FORECAST PROBLEMS WILL BE PRECIPITATION CHANCES TODAY...HOW COOL TO
MAKE HIGHS AND LOWS THROUGH FRIDAY NIGHT AND HOW MUCH TO WARM THINGS
UP ON SATURDAY. SATELLITE SHOWING AN ACTIVE FLOW FROM THE PACIFIC
INTO NORTH AMERICA. THE FLOW WAS AMPLIFYING SOME OVER THE PACIFIC...
ESPECIALLY ALONG THE WEST COAST. ONE SYSTEM IS PUSHING EAST ALONG THE
U.S AND CANADIAN BORDER. OUTFLOW FROM THUNDERSTORM CLUSTER TO OUR
NORTH HAS PUSHED THROUGH THE AREA WITH A COLD FRONT APPROACHING FROM
THE NORTHWEST.
AT JET LEVEL...THE SREF WAS DOING A LITTLE BETTER WITH THE JET
DEPICTION OVER OUR AREA. AT MID LEVELS...MODELS WERE HAVING A LITTLE
TROUBLE THE SPEED AND AMPLITUDE OF THE NORTHERN LOW. AT THIS TIME
IT APPEARS THE GFS AND UKMET WERE DOING A LITTLE BETTER THAN THE
ECMWF AND CANADIAN. THE RUC WAS CATCHING THE INITIAL WIND FIELD THE
BEST WITH THE ECMWF NOT TOO FAR BEHIND. THE UKMET AND GFS WERE DOING
A LITTLE BETTER THAN THE OTHER OUTPUT ON THE LOW LEVEL THERMAL
FIELD.
TODAY/TONIGHT...INTERESTING PRECIPITATION FORECAST. INITIAL ROUND OF
THUNDERSTORMS WERE CAUSED BY INITIAL SURFACE TROUGH AND OUTFLOW
BOUNDARY FROM CLUSTER OF THUNDERSTORMS THAT MOVED TO THE NORTH OF OUR
FORECAST AREA. HOWEVER ADDITIONAL DEVELOPMENT IS NOW OCCURRING IN
ADVANCE OF COLD FRONT WHICH IS VERY NEAR THE NORTHWEST CORNER OF THE
FORECAST AREA. ALSO AT THIS TIME...MAIN SHORTWAVE TROUGH ROTATING
AROUND NORTHERN UPPER LOW IS BEGINNING TO MOVE IN FROM THE WEST.
ALSO THE RIGHT REAR QUADRANT OF THE JET IS NEAR/OVER THE WESTERN END
OF THE FORECAST. DURING THE DAY THEY ALL HANDLE IT DIFFERENTLY.
HOWEVER...BY THE END OF THE AFTERNOON INTO THE EARLY AFTERNOON...THE
RIGHT REAR QUADRANT IS OVER OR NEAR THE EASTERN END OF THE AREA. IN
ADVANCE OF ALL THESE FEATURES THERE APPEARS ENOUGH ELEVATED CAPE WITH
FAVORABLE THETA-E LAPSE RATES TO ALLOW FOR A GOOD RESPONSE TO THE
LIFT. AT THIS TIME IT LOOKS LIKE THE FAVORED AREA FOR THUNDERSTORMS
IS ALONG AND EAST OF THE COLORADO BORDER...GETTING HIGHER AS YOU GO
EAST. KEPT THIS GENERAL IDEA FROM THE DAY SHIFT BUT RAISED POPS
SLIGHTLY FURTHER EAST. THUNDERSTORMS LOOK TO BE DONE BY LATE IN THE
DAY.
DEFINITELY LOOKS COOLER. THE QUESTION IS HOW MUCH. THE AMOUNT OF
TEMPERATURE CHANGE OVER YESTERDAY WOULD YIELD SLIGHTLY COOLER
TEMPERATURES THAN WHAT I HAVE IN THERE NOW. DID MAKE SLIGHT
ADJUSTMENTS COOLER IN LINE WITH THE BIAS ADJUSTMENT TO THE 850 MB
TEMPERATURES. THIS TENDED TO BE IN THE MIDDLE OF THE GUIDANCE. WILL
BE A RATHER COOL NIGHT TONIGHT WITH LITTLE CLOUD COVER AND LIGHT
WINDS. MODELS DIFFER ON WHERE THE LIGHTEST WINDS WILL BE. AT THIS
TIME IT LOOKS THEY WILL BE IN THE WESTERN AND NORTHERN SECTIONS AND
ADJUSTED ACCORDINGLY.
FRIDAY/FRIDAY NIGHT...MID/UPPER RIDGE BUILDING INTO THE AREA WILL
MAKE FOR DRY CONDITIONS AND LITTLE TO NO CLOUD COVER. SURFACE RIDGE
JUST PULLING OFF TO THE EAST DURING THE DAY WITH LIGHT AND
VARIABLE WINDS...ESPECIALLY IN THE EAST. MODELS ARE INDICATING
TEMPERATURES NEAR WHAT THEY ARE TO BE TODAY. ONLY MADE SLIGHT
ADJUSTMENTS BASED ON THAT. SOME DIFFERENCES IN HOW COOL TO MAKE THE
MINS. THE NAM STARTS WARM ADVECTION MUCH FASTER WITH THE OTHER MODELS
SLOWER. IT SHOULD BE WARMER BUT AM NOT GOING AS WARM AS THE NAM.
SATURDAY/SATURDAY NIGHT...MID/UPPER LEVEL RIDGE STARTS PUSHING EAST
LATE IN THE DAY AND ESPECIALLY IN THE NIGHT WITH SOUTHWEST FLOW
ALOFT DEVELOPING OVER THE AREA. THIS RIDGE PLUS VERY DRY/WELL MIXED
AIR MASS ALOFT WILL KEEP CONDITIONS DRY...DESPITE THE FACT AN UPPER
JET APPROACHES THE WESTERN PORTIONS OF THE AREA LATE IN THE NIGHT.
SHOULD BE WARMER...QUESTION IS HOW MUCH WARMER. NAM CONTINUES TO BE
THE MOST AGGRESSIVE WITH THIS. WIND FIELD AND CONSENSUS OF 850 MB
TEMPERATURES SUPPORT GOING COOLER. THIS IS CLOSE TO WHAT CURRENT
FORECAST HAS IN THERE AND ONLY MADE SLIGHT ADJUSTMENTS.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 300 AM MDT THU SEP 19 2013
A SHORTWAVE TROUGH WILL QUICKLY MOVE THROUGH SUNDAY NIGHT. THE
STRONGEST FORCING WILL BE NORTH OF THE FORECAST AREA ACROSS NEBRASKA
WHERE GFS ENSEMBLE MEAN QPF VALUES ARE HIGHEST. ISOLATED TO
SCATTERED CONVECTION SHOULD IMPACT THE WESTERN PORTION OF THE
FORECAST AREA BY SUNDAY EVENING AND THEN OVERSPREAD THE REST OF
THE AREA OVERNIGHT. THE GREATEST RAIN CHANCES AND POTENTIAL FOR
THE HIGHEST RAINFALL AMOUNTS WILL BE OVER ROUGHLY THE NORTHEASTERN
HALF OF THE FORECAST AREA. SLIGHTLY COOLER TEMPERATURES WILL
ARRIVE BEHIND THIS SHORTWAVE AND ASSOCIATED COLD FRONT ON MONDAY
BUT COLD AIR ADVECTION IN THE WAKE OF THIS SYSTEM IS BRIEF AND
INSIGNIFICANT. STRONG EAST TO WEST ORIENTED MID/UPPER FLOW WILL BE
SITUATED OVER THE NORTHERN ROCKIES AND NORTHERN PLAINS ON TUESDAY.
BY MID WEEK A LARGE TROUGH EVOLVES OVER THE WESTERN CONUS. MODELS
DIFFER ON HOW THIS TROUGH WILL EVOLVE BY MID WEEK WITH GFS AND
ECMWF DIFFERING ON THE POSITION OF CLOSED UPPER LOW...MEANWHILE
GFS ENSEMBLE MEAN DEPICTS A MORE OPEN/PROGRESSIVE TROUGH. IN
EITHER SCENARIO...SIGNIFICANT IMPACTS TO OUR AREA ARE NOT EXPECTED
THROUGH THE END OF THE EXTENDED PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 545 AM MDT THU SEP 19 2013
VFR CONDITIONS ARE EXPECTED TO CONTINUE FOR THE TAF PERIOD AT BOTH
TAF SITES. A SMALL SPREAD IN TEMPERATURE AND DEW POINT AT MCK
COULD LEAD TO MINOR REDUCTION OF VISIBILITY BRIEFLY THIS
MORNING...BUT NO VISIBILITY OR CEILING RESTRICTIONS ARE EXPECTED.
THERE IS SOME DISAGREEMENT IN MODEL GUIDANCE ON HOW EXTENSIVE
CLOUDS WILL BE THROUGH AFTERNOON. A BROKEN DECK IS A POSSIBILITY
BUT SHOULD REMAIN JUST ABOVE MVFR CRITERIA. WINDS WILL INCREASE THIS
AFTERNOON FROM THE NORTH AND VEER TO A NORTHEASTERLY DIRECTION BY
EVENING. GUSTS OVER 20 KNOTS ARE EXPECTED FROM LATE MORNING
THROUGH MID AFTERNOON.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JTL
SHORT TERM...BULLER
LONG TERM...BRB
AVIATION...BRB
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
857 AM CDT Thu Sep 19 2013
...Updated to precipitation chances today...
.SYNOPSIS...
ISSUED AT 1020 PM CDT WED SEP 18 2013
Water vapor imagery and upper air analysis indicate an upper level
trough of low pressure pushing eastward across the northern
Rockies of Montana and Wyoming. Near the surface, a lee side
trough of low pressure remains anchored across extreme eastern
Colorado. Surface dewpoints are in the upper 50s(F) to the lower
and mid 60s(F) across central and southwest Kansas.
&&
.UPDATE...
ISSUED AT 844 AM CDT THU SEP 19 2013
Scatted showers and even a few isolated thunderstorms will
continue across western and north central Kansas as an upper level
disturbance based the nam 450mb- 400mb pv lifts northeast across
western Kansas. HRRR appears to have a decent handle on this so
will lean in that direction for precipitation chances through the
early afternoon. Thunderstorms still appear become more widespread
across south central Kansas during the mid to late afternoon as a
cold front moves into south central Kansas, late day instability,
and the location of the left exit region of an upper level jet at
00z Friday. Also trended towards a non diurnal trend in
temperatures this afternoon behind the cold front as it crosses
western Kansas.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 212 AM CDT THU SEP 19 2013
Short range models indicate the upper level trough kicking out of
the Rockies into the Northern Plains today setting up shower and
thunderstorm chances across the Upper Midwest southwestward into the
Central Plains, including portions of central and western Kansas.
As the upper level trough moves into the Dakotas and Nebraska, an
attendant cold front will push southeastward into western Kansas
late this morning into the afternoon. Meanwhile, a +85kt upper level
jet is projected to climb northeast out of the desert southwest into
western and central Kansas from this afternoon into this evening.
Along with more favorable dynamic support aloft, steepening mid
level lapse rates and increased instability will be enough to
support thunderstorm development along and ahead of the cold front
as it begins to push further southeast into more favorable
moisture across central Kansas and eastern portions of southwest
Kansas. Although vertical shear profiles are not exactly ideal,
CAPE values in excess of 2000 J/KG ahead of the front will be
enough to support strong to marginally severe thunderstorms...mainly
southeast of a Hays to Liberal line. The potential for heavy
rainfall exists as well with NAM/GFS model soundings showing PW
values up around 1.5 inches.
Temperatures are expected to climb back up into the lower 90s(F)
across south central Kansas where the frontal passage isn`t likely
to occur until late this afternoon. Otherwise, look for highs up
into the upper 70s(F) and 80s(F) behind the front with the cooler
temperatures across west central Kansas. Lows generally down into
the 50s(F) are likely tonight as much cooler air filters south into
western Kansas overnight.
.LONG TERM...(Friday through Wednesday)
ISSUED AT 311 AM CDT THU SEP 19 2013
A deep upper level shortwave trough will be moving out of the
northern and central plains by Friday morning. The associated
surface cold front will be well to the southeast of western
Kansas with clear skies and cooler temperatures in its wake.
The medium range models show a fairly progressive upper level
pattern across North America through the remainder of the extended
period. An upper level ridge will move east over the central High
Plains Saturday and Sunday before another strong shortwave trough
moves out of the Rockies into the central High Plains Sunday
night and Monday. The atmosphere is not progged to be overly
unstable but the GFS and ECMWF both show a 70 knot upper level jet
propagating across the Oklahoma/Texas panhandles Sunday night.
With western Kansas under the left exit region of this jet, think
that the going 30-40 percent pops for thunderstorms looks
reasonable.
Upper level ridging builds back over the central part of the
country through midweek ahead of another strong wave that digs
into the western states. We should see dry weather through midweek
before precipitation chances increase by next weekend.
&&
.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
ISSUED AT 649 AM CDT THU SEP 19 2013
Widely scattered thunderstorms will be possible across western and
central Kansas today as a cold front pushes south across the
western part of the state. Will carry VCTS at the taf sites
through much of the day. Depending on thunderstorm trends,
thunderstorms may need to be added to tempo or prevailing groups
this afternoon. Southwesterly winds will become westerly ahead of
the front this morning before switching to the north to northeast
behind the front this afternoon. Showers and thunderstorms will be
moving out of the region by this evening.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 85 55 78 50 / 30 30 0 0
GCK 80 53 76 50 / 30 10 0 0
EHA 82 52 76 52 / 40 10 0 0
LBL 85 55 79 51 / 30 20 0 0
HYS 80 52 75 50 / 40 10 0 0
P28 92 60 80 52 / 80 80 10 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Burgert
SYNOPSIS...JJohnson
SHORT TERM...JJohnson
LONG TERM...Gerard
AVIATION...Gerard
AREA FORECAST DISCUSSION
NWS GOODLAND KS
545 AM MDT THU SEP 19 2013
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 358 AM MDT THU SEP 19 2013
FORECAST PROBLEMS WILL BE PRECIPITATION CHANCES TODAY...HOW COOL TO
MAKE HIGHS AND LOWS THROUGH FRIDAY NIGHT AND HOW MUCH TO WARM THINGS
UP ON SATURDAY. SATELLITE SHOWING AN ACTIVE FLOW FROM THE PACIFIC
INTO NORTH AMERICA. THE FLOW WAS AMPLIFYING SOME OVER THE PACIFIC...
ESPECIALLY ALONG THE WEST COAST. ONE SYSTEM IS PUSHING EAST ALONG THE
U.S AND CANADIAN BORDER. OUTFLOW FROM THUNDERSTORM CLUSTER TO OUR
NORTH HAS PUSHED THROUGH THE AREA WITH A COLD FRONT APPROACHING FROM
THE NORTHWEST.
AT JET LEVEL...THE SREF WAS DOING A LITTLE BETTER WITH THE JET
DEPICTION OVER OUR AREA. AT MID LEVELS...MODELS WERE HAVING A LITTLE
TROUBLE THE SPEED AND AMPLITUDE OF THE NORTHERN LOW. AT THIS TIME
IT APPEARS THE GFS AND UKMET WERE DOING A LITTLE BETTER THAN THE
ECMWF AND CANADIAN. THE RUC WAS CATCHING THE INITIAL WIND FIELD THE
BEST WITH THE ECMWF NOT TOO FAR BEHIND. THE UKMET AND GFS WERE DOING
A LITTLE BETTER THAN THE OTHER OUTPUT ON THE LOW LEVEL THERMAL
FIELD.
TODAY/TONIGHT...INTERESTING PRECIPITATION FORECAST. INITIAL ROUND OF
THUNDERSTORMS WERE CAUSED BY INITIAL SURFACE TROUGH AND OUTFLOW
BOUNDARY FROM CLUSTER OF THUNDERSTORMS THAT MOVED TO THE NORTH OF OUR
FORECAST AREA. HOWEVER ADDITIONAL DEVELOPMENT IS NOW OCCURRING IN
ADVANCE OF COLD FRONT WHICH IS VERY NEAR THE NORTHWEST CORNER OF THE
FORECAST AREA. ALSO AT THIS TIME...MAIN SHORTWAVE TROUGH ROTATING
AROUND NORTHERN UPPER LOW IS BEGINNING TO MOVE IN FROM THE WEST.
ALSO THE RIGHT REAR QUADRANT OF THE JET IS NEAR/OVER THE WESTERN END
OF THE FORECAST. DURING THE DAY THEY ALL HANDLE IT DIFFERENTLY.
HOWEVER...BY THE END OF THE AFTERNOON INTO THE EARLY AFTERNOON...THE
RIGHT REAR QUADRANT IS OVER OR NEAR THE EASTERN END OF THE AREA. IN
ADVANCE OF ALL THESE FEATURES THERE APPEARS ENOUGH ELEVATED CAPE WITH
FAVORABLE THETA-E LAPSE RATES TO ALLOW FOR A GOOD RESPONSE TO THE
LIFT. AT THIS TIME IT LOOKS LIKE THE FAVORED AREA FOR THUNDERSTORMS
IS ALONG AND EAST OF THE COLORADO BORDER...GETTING HIGHER AS YOU GO
EAST. KEPT THIS GENERAL IDEA FROM THE DAY SHIFT BUT RAISED POPS
SLIGHTLY FURTHER EAST. THUNDERSTORMS LOOK TO BE DONE BY LATE IN THE
DAY.
DEFINITELY LOOKS COOLER. THE QUESTION IS HOW MUCH. THE AMOUNT OF
TEMPERATURE CHANGE OVER YESTERDAY WOULD YIELD SLIGHTLY COOLER
TEMPERATURES THAN WHAT I HAVE IN THERE NOW. DID MAKE SLIGHT
ADJUSTMENTS COOLER IN LINE WITH THE BIAS ADJUSTMENT TO THE 850 MB
TEMPERATURES. THIS TENDED TO BE IN THE MIDDLE OF THE GUIDANCE. WILL
BE A RATHER COOL NIGHT TONIGHT WITH LITTLE CLOUD COVER AND LIGHT
WINDS. MODELS DIFFER ON WHERE THE LIGHTEST WINDS WILL BE. AT THIS
TIME IT LOOKS THEY WILL BE IN THE WESTERN AND NORTHERN SECTIONS AND
ADJUSTED ACCORDINGLY.
FRIDAY/FRIDAY NIGHT...MID/UPPER RIDGE BUILDING INTO THE AREA WILL
MAKE FOR DRY CONDITIONS AND LITTLE TO NO CLOUD COVER. SURFACE RIDGE
JUST PULLING OFF TO THE EAST DURING THE DAY WITH LIGHT AND
VARIABLE WINDS...ESPECIALLY IN THE EAST. MODELS ARE INDICATING
TEMPERATURES NEAR WHAT THEY ARE TO BE TODAY. ONLY MADE SLIGHT
ADJUSTMENTS BASED ON THAT. SOME DIFFERENCES IN HOW COOL TO MAKE THE
MINS. THE NAM STARTS WARM ADVECTION MUCH FASTER WITH THE OTHER MODELS
SLOWER. IT SHOULD BE WARMER BUT AM NOT GOING AS WARM AS THE NAM.
SATURDAY/SATURDAY NIGHT...MID/UPPER LEVEL RIDGE STARTS PUSHING EAST
LATE IN THE DAY AND ESPECIALLY IN THE NIGHT WITH SOUTHWEST FLOW
ALOFT DEVELOPING OVER THE AREA. THIS RIDGE PLUS VERY DRY/WELL MIXED
AIR MASS ALOFT WILL KEEP CONDITIONS DRY...DESPITE THE FACT AN UPPER
JET APPROACHES THE WESTERN PORTIONS OF THE AREA LATE IN THE NIGHT.
SHOULD BE WARMER...QUESTION IS HOW MUCH WARMER. NAM CONTINUES TO BE
THE MOST AGGRESSIVE WITH THIS. WIND FIELD AND CONSENSUS OF 850 MB
TEMPERATURES SUPPORT GOING COOLER. THIS IS CLOSE TO WHAT CURRENT
FORECAST HAS IN THERE AND ONLY MADE SLIGHT ADJUSTMENTS.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 300 AM MDT THU SEP 19 2013
A SHORTWAVE TROUGH WILL QUICKLY MOVE THROUGH SUNDAY NIGHT. THE
STRONGEST FORCING WILL BE NORTH OF THE FORECAST AREA ACROSS NEBRASKA
WHERE GFS ENSEMBLE MEAN QPF VALUES ARE HIGHEST. ISOLATED TO
SCATTERED CONVECTION SHOULD IMPACT THE WESTERN PORTION OF THE
FORECAST AREA BY SUNDAY EVENING AND THEN OVERSPREAD THE REST OF
THE AREA OVERNIGHT. THE GREATEST RAIN CHANCES AND POTENTIAL FOR
THE HIGHEST RAINFALL AMOUNTS WILL BE OVER ROUGHLY THE NORTHEASTERN
HALF OF THE FORECAST AREA. SLIGHTLY COOLER TEMPERATURES WILL
ARRIVE BEHIND THIS SHORTWAVE AND ASSOCIATED COLD FRONT ON MONDAY
BUT COLD AIR ADVECTION IN THE WAKE OF THIS SYSTEM IS BRIEF AND
INSIGNIFICANT. STRONG EAST TO WEST ORIENTED MID/UPPER FLOW WILL BE
SITUATED OVER THE NORTHERN ROCKIES AND NORTHERN PLAINS ON TUESDAY.
BY MID WEEK A LARGE TROUGH EVOLVES OVER THE WESTERN CONUS. MODELS
DIFFER ON HOW THIS TROUGH WILL EVOLVE BY MID WEEK WITH GFS AND
ECMWF DIFFERING ON THE POSITION OF CLOSED UPPER LOW...MEANWHILE
GFS ENSEMBLE MEAN DEPICTS A MORE OPEN/PROGRESSIVE TROUGH. IN
EITHER SCENARIO...SIGNIFICANT IMPACTS TO OUR AREA ARE NOT EXPECTED
THROUGH THE END OF THE EXTENDED PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 545 AM MDT THU SEP 19 2013
VFR CONDITIONS ARE EXPECTED TO CONTINUE FOR THE TAF PERIOD AT BOTH
TAF SITES. A SMALL SPREAD IN TEMPERATURE AND DEW POINT AT MCK
COULD LEAD TO MINOR REDUCTION OF VISIBILITY BRIEFLY THIS
MORNING...BUT NO VISIBILITY OR CEILING RESTRICTIONS ARE EXPECTED.
THERE IS SOME DISAGREEMENT IN MODEL GUIDANCE ON HOW EXTENSIVE
CLOUDS WILL BE THROUGH AFTERNOON. A BROKEN DECK IS A POSSIBILITY
BUT SHOULD REMAIN JUST ABOVE MVFR CRITERIA. WINDS WILL INCREASE THIS
AFTERNOON FROM THE NORTH AND VEER TO A NORTHEASTERLY DIRECTION BY
EVENING. GUSTS OVER 20 KNOTS ARE EXPECTED FROM LATE MORNING
THROUGH MID AFTERNOON.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...BRB
AVIATION...BRB
AREA FORECAST DISCUSSION
NWS BILLINGS MT
906 AM MDT THU SEP 19 2013
.UPDATE...
WEAK SHORTWAVE IN NW FLOW ALOFT IS INTERACTING WITH SHALLOW BUT
MOIST LOW LEVEL INSTABILITY TO PRODUCE AREAS OF LIGHT SHOWERS OR
SPRINKLES FROM NEAR COLUMBUS EAST. IN FACT...CONVERGENT BAND HAS
DEVELOPED DOWNWIND OF THE SNOWIES...THUS THE LIGHT SHOWERS IN THE
BILLINGS AREA AT 9AM WITH A VEERED-TO-NORTH WIND. THIS ACTIVITY
SHOULD END BY NOON IN OUR WEST...BUT STRONGER ASCENT AND DEEPER
MOISTURE WILL IMPACT OUR EAST INTO THE AFTERNOON. RAP/NAM
SOUNDINGS SHOW MOIST LOW LEVELS PERSISTING THRU THE AFTERNOON.
HAVE THUS RAISED AND EXPANDED POPS FROM MILES CITY TO BAKER AND
EKALAKA...AND DROPPED TEMPS JUST A BIT. PRECIP AMOUNTS WILL BE
LIGHT BUT SHOULD AMOUNT TO A FEW HUNDREDTHS. TEMP AT BAKER COULD
STRUGGLE TO RISE ABOVE THE LOW 50S TODAY...ALONG WITH A BRISK NW
WIND WITH GUSTS TO 30 MPH. EASILY THE COOLEST DAY WE HAVE SEEN IN
A LONG TIME. JKL
&&
.SHORT TERM...VALID FOR TDY AND FRI...
UPPER TROUGH CROSSING THE REGION TONIGHT WILL CONTINUE TO EXERT
ITS INFLUENCE OVER OUR FORECAST AREA WELL INTO THURSDAY...
ESPECIALLY IN THE NORTHEAST ZONES. AS SUCH...SOME CHANGES HAVE
BEEN MADE FOR TODAY FORECAST.
EARLY THIS MORNING...THE MAIN 500MB COLD POOL WAS SITUATED OVER
SOUTHWEST MONTANA. THERE WAS ANOTHER MID LEVEL COLD POOL OVER
NORTH CENTRAL MONTANA AS WELL WITH AN ASSOCIATED FRONT PUSHING
EAST/SOUTHEAST ACROSS MONTANA. THIS FEATURE WILL SLIP DOWN
THROUGH OUR ZONES BY 6AM. THERE IS A CONSISTENT EFFORT FROM THE
MODELS TO BRING IN A LOW CLOUD DECK BEHIND THIS FEATURE...THICKEST
ACROSS CUTER AND FALLON COUNTIES. WHILE SOUNDINGS AND HRRR DATA
PARTIALLY BREAK MILES CITY OUT OF THIS IN THE AFTERNOON...THEY
SUGGEST BAKER AND FALLON COUNTY WILL PERSIST UNDER OVERCAST
CONDITIONS AS LONG AS 6PM. THIS SCENARIO IS A NOTORIOUS FORECAST
BUSTER FOR BAKER. UNLESS I SEE SOMETHING AT THE LAST MOMENT
SUGGESTING OTHERWISE...I WILL PLAN TO LOWER TEMPERATURES QUITE A
BIT IN THIS AREA.
ANOTHER CHANGE...THOUGH MINOR...WAS IN REGARD TO A TROWEL FEATURE
ON THE BACKSIDE OF THE TROUGH. THIS IS CURRENTLY GENERATING SOME
PRECIPITATION ALONG THE FRONT RANGE AND NORTHWEST MOUNTAINS. CROSS
SECTIONS SHOW SOME MODEST LIFT AND MOISTURE AS IT WORKS OVER OUR
FORECAST AREA THIS MORNING. IT WILL HAVE TO BATTLE A BRISK
DOWNSLOPE WIND...SO VIRGA AND SPRINKLES MAY BE THE MAIN
OUTCOME. HOWEVER...I HAVE SPREAD SOME LOW POPS BACK TO THE WEST
AS WELL AS A LITTLE FURTHER SOUTH INTO UPSLOPE AREAS NEAR THE BIG
HORNS FOR THE FIRST HALF OF THE DAY.
THE TROUGH AXIS WILL BE JUST EAST OF THE MONTANA/DAKOTA BORDER
BY EVENING. SO WE SHOULD SEE DECREASING CLOUDS AND WIND. LOWS MAY
DIP TO AROUND OR JUST BELOW AVERAGE FOR THIS TIME OF YEAR...MAKING
IT ONE OF THE OVERALL COOLEST WE HAVE HAD SO FAR THIS SEPTEMBER.
RIDGE BUILDS IN QUICKLY FOR TOMORROW WHICH WILL RESULT IN A NICE
BUMP IN THE MERCURY. BT
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
EXTENDED MODELS IN GOOD AGREEMENT FOR THIS WEEKEND GOING INTO
EARLY NEXT WEEK BUT DIVERGE WITH A LARGE SYSTEM ACROSS THE WESTERN
STATES BY MID NEXT WEEK. RIDGE AND ITS AXIS SHIFT EAST SATURDAY AS
AN UPPER LOW AND TROUGH MOVE ONTO THE PACIFIC NORTHWEST AND
NORTHERN CALIFORNIA COAST. SOUTHWEST FLOW ALOFT WILL PREVAIL ALONG
WITH ABOVE NORMAL TEMPERATURES AND A SLIGHT SHOWER/THUNDERSTORM
CHANCE. THE TROUGH ALONG WITH A COLD FRONT MOVE THROUGH THE
FORECAST AREA LATE SATURDAY NIGHT INTO SUNDAY MORNING BRINGING
BETTER CHANCES FOR SHOWERS WITH COOLER AND MORE NORMAL
TEMPERATURES FOR SUNDAY.
FAST ZONAL FLOW ALOFT LOOKS IN STORE FOR MONDAY AND TUESDAY WITH
MAINLY A DOWNSLOPE SURFACE FLOW KEEPING CONDITIONS DRY FOR THE
LOWER ELEVATIONS WITH SHOWERS FOR THE MOUNTAINS. BY LATE TUESDAY
INTO WEDNESDAY...AN UPPER LOW TAKES SHAPE ACROSS THE PACIFIC
NORTHWEST. MODELS DIVERGE GREATLY FROM THAT POINT ONWARD. THE GFS
TAKES THE LOW SOUTH INTO THE GREAT BASIN AREA WEDNESDAY AND
THURSDAY WHILE THE ECMWF EJECTS THE LOW NORTHEAST ACROSS MONTANA
BUT STILL KEEPING A TROUGH ACROSS THE CENTRAL AND NORTHERN
ROCKIES. EITHER SCENARIO WILL BRING INCREASING CHANCES FOR PRECIP
TO THE FORECAST AREA. HOWEVER...LOCATION AND AMOUNTS OF PRECIP
ALONG WITH TEMPEATURES VARY QUITE A BIT DEPENDING ON MODEL. WILL
KEEP CHANCE POPS FOR MID NEXT WEEK WITH HIGHEST CHANCES FOR THE
MOUNTAINS ALONG WITH A TREND TO COOLER TEMPERATURES. HOOLEY
&&
.AVIATION...
EXPECT MOSTLY CLOUDY SKIES TODAY WITH VFR CONDITIONS PREVAILING.
THE EXCEPTION WILL BE ISOLATED TO SCATTERED SHOWERS POSSIBLE ALONG
AND NORTH OF A KLVM - KBIL - KBHK LINE TODAY WHICH WILL RESULT IN
POSSIBLE MVFR CONDITIONS AT TIMES. MVFR TO IFR CONDITIONS WILL
ALSO BE POSSIBLE AT TIMES DUE TO LOW CEILINGS FROM KMLS EASTWARD.
GUSTY NORTHWEST WINDS WILL BE LIKELY EAST OF KBIL TOWARD KMLS TO
THE DAKOTA BORDERS. CHURCH
&&
.PRELIMINARY POINT TEMP/POPS...
TDY FRI SAT SUN MON TUE WED
-------------------------------------------------------
BIL 064 043/077 049/084 053/068 048/071 050/071 048/062
2/W 00/U 00/U 22/T 11/B 02/T 22/W
LVM 064 035/078 043/083 046/065 042/068 045/068 045/054
0/B 00/U 00/U 22/T 11/B 12/T 23/W
HDN 066 038/079 045/086 051/072 046/073 049/074 048/065
2/W 00/U 00/U 12/T 21/B 01/B 12/W
MLS 059 042/075 048/084 054/073 050/075 052/074 050/068
6/W 00/U 00/U 22/T 21/U 11/B 12/W
4BQ 061 038/075 045/084 053/075 047/074 049/075 047/068
2/W 00/U 00/U 12/T 21/U 11/U 12/W
BHK 055 037/072 044/080 050/075 047/073 048/074 047/069
6/W 00/U 00/U 12/T 21/U 11/U 12/W
SHR 063 036/076 046/084 050/070 044/071 047/072 045/064
1/B 00/U 00/U 12/T 30/U 01/U 12/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
729 AM CDT THU SEP 19 2013
.AVIATION...
12Z TAFS FOR KOMA...KOFK...KLNK
THE SURFACE COLD FRONT WILL MOVE THROUGH OFK BY MID MORNING AND
OMA/LNK BY EARLY AFTERNOON. SCT SHRA AND ISO TSRA ARE EXPECTED
WITH THE FRONT AT ALL 3 TAF SITES WITH SOME MVFR VISBY
POSSIBLE...BUT CIGS ARE EXPECTED TO REMAIN ABOVE MVFR RANGE. WILL
INCLUDE THUNDER AT ALL 3 SITES FOR A COUPLE OF HOURS...BUT THE
MAJORITY OF THE TIME IT WILL LIKELY BE JUST SHOWERS. THE PRECIP
WILL CLEAR OUT OF THE TAF SITES BY LATE AFTERNOON WITH SKIES
CLEARING OVERNIGHT.
&&
.PREV DISCUSSION... /ISSUED 251 AM CDT THU SEP 19 2013/
DISCUSSION...
GLANCE AT REGIONAL RADAR ALREADY SHOWING LINE OF CONVECTION FIRING
ALONG INTENSE SFC BAROCLINIC ZONE EXTENDING FROM ABOUT NRN MN TO
NWRN KS. BNDRY IN ASSOCIATION WITH UPPER SHORTWAVE TROF MIGRATING
ACROSS THE NRN PLAINS. AGEOSTROPHIC LIFT JUST AHEAD OF RELATIVELY
DEEP FRONTOGENESIS BNDRY IS QUITE STOUT...PER RUC13. ALSO...STRONG
UPPER LEVEL DIVG ASSOCIATE WITH RRQ OF JET MAX ALOFT CONTRIBUTING TO
ENHANCEMENT OF SYNOPTIC LIFT AS WELL.
SHORT TERM ISSUE IS TIMING THE FRONTAL PASSAGE/PCPN THRU THE CWA.
REGIONAL RADAR WAS SHOWING AN OUTFLOW BNDRY ASSOCIATED WITH CLUSTER
OF STORMS IN WRN NEB WAS QUICKLY PUSHING EAST...AND WILL PROBABLY
REACH THE CWA IN THE NEXT COUPLE HOURS. AT ANY RATE...SFC WIND PROGS
VIA TIME-SERIES INDICATE LEADING EDGE OF THE TRUE FRONT REACHING
KOFK BY LATE MORNING...THEN EARLY AFTN AT KLNK AND KOMA...THUS
APPROXIMATE TIME FRAME FOR FOR EXPECTED CONVECTION. MEANWHILE...
PERSISTENT MOISTURE ADV INTO THE REGION THE LAST 24 HRS HAS
CULMINATED IN A MOISTURE RICH ENVIRONMENT AS SEE BY PWS VALUES
RANGING ANYWHERE FROM 160%-220% ABOVE NORM AHEAD OF THE FRONT. AT
THIS POINT SUSPECT THAT PCPN INTENSITY WILL INCREASE THIS AFTN OVER
SRN CWA WHERE THE RUC13 IS SHOWING PRECIP EFFICIENCY/WARM CLOUD DEPTH
PEAKS. IMPROVING CONDITIONS THEN TONIGHT AS STABLE AIRMASS ENVELOPS
THE REGION. IN CASE OF LINGERING PCPN ACTIVITY...WILL MAINTAIN TOKEN
EVENING POPS SOUTH.
EXCELLENT WEATHER ON TAP THIS WEEKEND IN RESPONSE TO UPPER RIDGE
BUILDING OVER THE PLAINS.
NEXT ROUND OF PCPN COMES SUNDAY NIGHT/MONDAY WHEN NEXT POTENT
SHORTWAVE TROF EXITS THE ROCKIES AND SWEEPS ANOTHER COLD FRONT INTO
THE CNTRL PLAINS. WITH GFS AND ECM IN AGREEMENT DECENT LLVL
MOISTURE FEED PRECEDING THE FRONT...GENEROUS RAINFALL AMOUNTS WILL
ONCE AGAIN BE POSSIBLE.
DEE
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BISMARCK ND
645 AM CDT THU SEP 19 2013
.UPDATE...
ISSUED AT 645 AM CDT THU SEP 19 2013
NO SIGNIFICANT CHANGES WITH THIS UPDATE. THE FORECAST FOR THE
REMAINDER OF THE DAY WAS BLENDED TO THE 10 UTC RAP AND 06 UTC NAM
GIVEN THEIR GOOD HANDLE OF THE STRATUS FIELD THAT IS OVERTAKING
THE AREA. DID LOWER HIGHS A FEW DEGREES FROM THE PREVIOUS FORECAST
ALONG AND WEST OF HIGHWAY 83 AS LOW LEVEL COLD AIR ADVECTION AND
CLOUD COVER WILL SIGNIFICANTLY LIMIT TEMPERATURE RECOVERY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 256 AM CDT THU SEP 19 2013
LATEST WATER VAPOR IMAGERY SHOWS A DRY SLOT COVERING MOST OF
WESTERN AND CENTRAL NORTH DAKOTA THIS MORNING. UPPER LOW CIRCULATING
OVER NORTHEAST MONTANA IS FORECAST TO SHIFT EAST INTO THE DEVILS
LAKE AREA BY THURSDAY NIGHT. INSTABILITY SHOWERS WILL CONTINUE TO WRAP
AROUND THE LOW AND SLIDE MAINLY ACROSS NORTHERN NORTH DAKOTA TODAY.
HAVE REMOVED THE MENTION OF THUNDER WITH SOUNDINGS SHOWING A STABLE
PATTERN ALONG WITH A HIGH RH FIELD IN THE H85-H7 LAYER. THE
NAM/RUC H85 RH FIELD SHOWS A LARGE SHIELD OF CLOUDY SKIES MOVING
SOUTHEAST FROM SOUTHERN SASKATCHEWAN AND NORTHEAST MONTANA. THIS
IS VERIFIED ON THE FOG/STRATUS LOOP. PATCHY FOG WAS ALSO
ACCOMPANYING THE STRATUS DECK. SOUNDINGS INDICATE BREEZY WINDS
TODAY WITH THE STRONGEST WINDS IN THE SOUTHWEST...HOWEVER WILL NOT
ISSUE A WIND ADVISORY AS WINDS ARE FORECAST TO REMAIN BELOW
CRITERIA...AS MIXING WILL BE LIMITED DUE TO THE EXTENSIVE LOW
LEVEL CLOUD COVER FORECAST TODAY. HIGHS WILL BE IN THE UPPER 50S
WEST TO AROUND 70F FAR SOUTHEAST. WILL NEED TO MONITOR THE FAR
SOUTHWEST FOR A POSSIBLE FROST ADVISORY FRIDAY MORNING AS CLEARING
SKIES ARRIVE LATE THURSDAY NIGHT WITH HETTINGER POSSIBLY DOWN TO
35F FOR A LOW TEMPERATURE. ELSEWHERE...EXPECT A SLOW DECREASE IN
CLOUDS FOR CENTRAL NORTH DAKOTA THURSDAY NIGHT WHICH WILL HELP TO
KEEP OVERNIGHT LOWS IN THE LOWER 40S.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 256 AM CDT THU SEP 19 2013
THE HIGHLIGHTS OF THE EXTENDED FORECAST ARE FROST POTENTIAL FRIDAY
NIGHT AND THUNDERSTORMS SUNDAY NIGHT INTO MONDAY.
THE 00 UTC GUIDANCE SUITE IS IN GOOD AGREEMENT ON COOL SURFACE
HIGH PRESSURE ACROSS WESTERN AND CENTRAL NORTH DAKOTA ON FRIDAY.
GIVEN LITTLE MIXING AND A COOL MORNING START...WIDESPREAD HIGHS IN
THE LOW TO MID 60S ARE FORECAST...WHICH PERHAPS A FEW READINGS IN
THE 50S ACROSS THE TURTLE MOUNTAINS AND JAMES RIVER VALLEY.
SURFACE HIGH PRESSURE PROPAGATES INTO FAR WESTERN MINNESOTA FRIDAY
NIGHT...WITH RETURN FLOW COMMENCING ACROSS WESTERN NORTH DAKOTA.
HOWEVER...THE COOL DAYTIME TEMPERATURES FRIDAY SET THE STAGE FOR
FROST POTENTIAL WITH WIDESPREAD LOWS IN THE 30S POSSIBLE FOR
CENTRAL NORTH DAKOTA WHERE RETURN FLOW WILL NOT ESTABLISH ITSELF.
THEREAFTER...TEMPERATURES TREND BACK TO NEAR TO SLIGHTLY ABOVE
NORMAL WITH HIGHS IN THE 70S SATURDAY AND SUNDAY UNDER A HIGH
AMPLITUDE UPPER LEVEL RIDGE. THE 00 UTC DETERMINISTIC MODELS ALL
DEPICT A POTENT SHORTWAVE PROPAGATING INTO THE NORTHERN PLAINS
SUNDAY NIGHT INTO MONDAY...WITH WIDESPREAD CONVECTION POSSIBLE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 645 AM CDT THU SEP 19 2013
LATEST SATELLITE AND SURFACE OBSERVATIONS SHOW MVFR/IFR CIGS
ACROSS THE NORTHERN AERODROMES OF KISN/KMOT. ANOTHER AREA OF MVFR
CIGS IN EASTERN MONTANA WILL SWEEP INTO KDIK BY 13Z...INTO KBIS BY
AROUND 15Z...AND KJMS BY MID AFTERNOON. MVFR CIGS WILL BE LOCKED
IN PLACE THROUGH 03Z FRIDAY WITH A GRADUAL RETURN TO VFR IN THE
WEST BY 06Z AND CENTRAL BETWEEN 06Z AND 12Z FRIDAY. BREEZY
NORTHWEST WINDS OF 15 TO 25 MPH CAN BE EXPECTED ACROSS
WESTERN/CENTRAL NORTH DAKOTA TODAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...KS
LONG TERM...AYD
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
634 AM EDT THU SEP 19 2013
.SYNOPSIS...
A SERIES OF UPPER LEVEL DISTURBANCES WILL RESULT IN A CHANCE OF
SHOWERS AND THUNDERSTORMS TODAY INTO TONIGHT. SHOWERS AND
THUNDERSTORMS WILL BECOME MORE WIDESPREAD FRIDAY AFTERNOON INTO
FRIDAY NIGHT AS A COLD FRONT APPROACHES FROM THE WEST. SHOWERS AND
A FEW THUNDERSTORMS WILL CONTINUE INTO SATURDAY BEFORE A DRIER AND
COOLER AIRMASS SETTLES INTO THE REGION FOR THE FIRST PART OF NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A PERSISTENT MCV HAS BEEN PROGRESSING VERY SLOWLY SOUTHEAST ACROSS
NORTHERN INDIANA THROUGH THE OVERNIGHT HOURS. SO FAR IT HAS NOT
SHOWED TOO MAY SIGNS OF DISSIPATING OR EVEN WEAKENING AND THE LAST SEVERAL
RUNS OF THE HRRR HAVE BEEN CONSISTENTLY TRYING TO PUSH IT
SOUTHEAST INTO OUR AREA THROUGH MID MORNING. THE AIRMASS ACROSS
OUR AREA IS MORE STABLE WITH THE INSTABILITY GRADIENT DROPPING OFF
FAIRLY QUICKLY ACROSS EASTERN INDIANA INTO WESTERN OHIO. AS A
RESULT..WOULD EXPECT THE BETTER CHANCE OF THUNDERSTORM MAINTENANCE
TO WORK MORE TO THE SOUTH AND STAY WEST OF MOST OF OUR AREA
THROUGH THE MORNING HOURS. HOWEVER...THE 850-300 MB MEAN WIND IS
MORE WESTERLY ACROSS NORTHERN INDIANA...BECOMING SOUTHEASTERLY
ACROSS OUR AREA. THIS WOULD SUGGEST A DECENT CHANCE THAT SOME OF
THE SHOWER ACTIVITY WILL WORK ITS WAY INTO AT LEAST THE WESTERN
HALF OF OUR FA OVER THE NEXT SEVERAL HOURS.
MEANWHILE...ABUNDANT LOW LEVEL MOISTURE ACROSS OUR AREA HAS ALLOWED
FOR SOME FAIRLY WIDESPREAD STRATUS DEVELOPMENT ACROSS ABOUT THE
SOUTHEAST TWO THIRDS OF OUR FA. WITH THE LOW LEVELS REMAINING MIXY
THROUGH DAYBREAK...WOULD NORMALLY NOT BE SURPRISED TO SEE THE
STRATUS EXPAND A LITTLE MORE...BUT THE DEBRIS CLOUDS FROM THE MCV
MAY MITIGATE THIS TO SOME DEGREE. EITHER WAY...THE COMBINATION OF
THE DEBRIS CLOUDS AND STRATUS DECK SHOULD KEEP US MAINLY CLOUD
THROUGH THE MORNING HOURS. THIS MAY ALSO HAVE AN IMPACT ON
TEMPERATURES AND HOW WELL WE DESTABILIZE THROUGH THIS AFTERNOON. IN
THE WESTERLY TO SOUTHWESTERLY LOW LEVEL WAA PATTERN...WOULD EXPECT
TO SEE SOME DECENT EROSION/DISSIPATION OF THE LOWER CLOUDS
THROUGH LATE MORNING/EARLY AFTERNOON WHICH SHOULD EVENTUALLY ALLOW
FOR PARTLY SUNNY SKIES. WILL NUDGE DOWN HIGHS JUST A TAD...GENERALLY
RANGING FROM UPPER 70S EAST TO LOWER 80S WEST. THIS WOULD STILL
ALLOW US TO DESTABILIZE THROUGH THIS AFTERNOON WITH ML CAPES PUSHING
UP CLOSE TO 1000 J/KG. AS A RESULT...WILL GO AHEAD AND ALLOW FOR
SOME CHANCE POPS ACROSS MUCH OF THE AREA THROUGH THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
THE 00Z NAM/GFS AND CMC ARE ALL TRYING TO HINT AT SOME SORT OF
CONTINUING PCPN OR REDEVELOPMENT TONIGHT SOMEWHERE ACROSS OUR AREA
WHILE THE 00Z ECMWF IS DRY. IT DOES LOOK LIKE WE COULD BE ON THE
EDGE OF A SOUTHWEST TO NORTHEAST ORIENTED 925-850 MB LOW LEVEL
JET LATER TONIGHT AND THIS COULD SERVE AS A FOCUSING MECHANISM.
AS A RESULT..WILL HANG ON TO SOME LOWER END POPS...BUT CONFIDENCE
IS NOT ALL THAT HIGH.
A COLD FRONT WILL MOVE ACROSS THE AREA FRIDAY NIGHT. AHEAD OF
THIS...WE SHOULD WARM UP FAIRLY WELL THROUGH THE DAY WITH HIGHS
PUSHING UP INTO THE LOW TO MID 80S. THIS WILL ALLOW US TO
DESTABILIZE ONCE AGAIN WITH MLCAPES AGAIN UP CLOSE TO 1000 J/KG.
THIS SHOULD LEAD TO SOME SCATTERED PRE FRONTAL SHOWERS AND
THUNDERSTORMS THROUGH THE DAY. BETTER LOW LEVEL CONVERGENCE JUST
AHEAD OF THE FRONT WILL PUSH INTO OUR NORTHWEST LATE FRIDAY
AFTERNOON AND THEN PROGRESS SOUTHEAST ACROSS OUR AREA THROUGH FRIDAY
EVENING. THIS WILL ALLOW FOR A MORE ORGANIZED LINE OF SHOWERS AND
THUNDERSTORMS. DEEP LAYER SHEAR IS NOT TERRIBLY STRONG INITIALLY WITH
THE PCPN FRIDAY AFTERNOON/FRIDAY EVENING...BUT THE 0-3 KM SHEAR
VALUES DO PUSH UP INTO THE 25 TO 30 KNOT RANGE. THIS MAY BE
ENOUGH TO SUPPORT SOME MARGINALLY SEVERE STORMS LATE FRIDAY
AFTERNOON INTO FRIDAY EVENING....ESPECIALLY ACROSS OUR NORTHWEST.
AS THE FRONT PUSHES OFF TO THE SOUTHEAST...EXPECT PCPN TO TAPER
OFF FROM NORTHWEST TO SOUTHEAST DURING THE DAY ON SATURDAY.
HIGH PRESSURE AND A COOLER AIRMASS WILL BUILD INTO THE AREA THROUGH
THE LATER PART OF THE WEEKEND. HIGHS ON SATURDAY WILL BE IN THE 70-75
DEGREE RANGE WITH HIGHS ON SUNDAY IN THE UPPER 60S TO NEAR 70.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
ON MONDAY...HIGH PRESSURE WILL BUILD IN FROM THE NORTH. COULD SEE
ENOUGH MOISTURE FROM THE LOW MOVING UP THE COAST TO PRODUCE
ISOLATED SHOWERS IN THE EXTREME EAST. AFTER MONDAY...SURFACE HIGH
PRESSURE EXTENDING INTO THE REGION FROM THE NE WILL BRING DRY
WEATHER AND MILD TEMPERATURES.
&&
.AVIATION /10Z THURSDAY THROUGH MONDAY/...
UNSETTLED WEATHER CONDITIONS WILL CONTINUE THROUGH THE NEXT
SEVERAL DAYS UNTIL A COLD FRONT PUSHES THROUGH SATURDAY MORNING.
MOISTURE CONTINUES TO INCREASE OVER THE OHIO VALLEY...RESULTING IN
INCREASING CLOUDS...SHOWERS AND A FEW THUNDERSTORMS.
THE SHOWER AND THUNDERSTORM COMPLEX WHICH ORIGINATED OVER NORTHERN
ILLINOIS LATE YESTERDAY EVENING CONTINUES TO PUSH SOUTHEAST AND IS CURRENTLY
LOCATED OVER CENTRAL INDIANA AND WEST CENTRAL OHIO. THIS PRECIPITATION
COMPLEX IS EXPECTED TO MOVE THROUGH THE AREA THIS MORNING AND
EARLY AFTERNOON. THERE IS A RISK OF THUNDERSTORMS WITH THIS
COMPLEX OVER THE WESTERN TAF SITES AND THIS HAS BEEN INCLUDED IN
THE FORECAST. AHEAD OF THIS AREA CONDITIONS ARE IFR DUE TO FOG AND
STRATUS. AS THE PRECIPITATION MOVES INTO THESE AREAS THE IFR
CONDITIONS SHOULD IMPROVE RAPIDLY. IN THE RAIN AREAS AFTER THE IFR
CONDITIONS HAVE IMPROVED EXPECT VFR WITH MVFR CIGS AND VSBY IN
THE HEAVIER SHOWERS AND THUNDERSTORMS.
ONCE THESE CONDITIONS MOVE TO THE EAST AND SOUTHEAST OF THE
FORECAST AREA THERE SHOULD BE A SIGNIFICANT BREAK WHERE VFR
CONDITIONS DOMINATE THE FORECAST AREA WELL INTO THE NIGHTTIME
HOURS. THEN FOG AND POSSIBLE STRATUS ONCE AGAIN WILL RETURN.
THESE CONDITIONS ARE MENTIONED IN THE FORECAST BUT TIMING AND
AREAL EXTENT OF COVERAGE WILL HAVE TO BE FINE TUNED IN LATER
FORECASTS.
OUTLOOK...THUNDERSTORMS WILL BE POSSIBLE FROM FRIDAY AFTERNOON
THROUGH SATURDAY MORNING.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...JGL
NEAR TERM...JGL
SHORT TERM...JGL
LONG TERM...PARKER
AVIATION...HAYDU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
607 AM EDT THU SEP 19 2013
.SYNOPSIS...
HIGH PRESSURE CENTERED OVER EASTERN PENNSYLVANIA TODAY WILL SLIDE
OFF THE EAST COAST FRIDAY. A COLD FRONT WILL PUSH EAST ACROSS THE
STATE SATURDAY AND SATURDAY NIGHT. ANOTHER SLOW MOVING HIGH
PRESSURE SYSTEM WILL THEN BUILD INTO THE REGION SUNDAY AND REMAIN
OVER THE AREA THROUGH MUCH OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SATELLITE SHOWS AN EXPANDING AREA OF STRATOCU ACROSS WESTERN PA
EARLY THIS AM...THE RESULT OF COOLING/MOISTENING BLYR BENEATH A
STRONG SUBSIDENCE INVERSION. SATL TRENDS SUGGEST ROUGHLY THE
WESTERN HALF OF THE STATE WILL BE COVERED BY THIS DECK OF LOW
CLOUDS BY 12Z. WHERE SKIES HAVE REMAINED CLEAR...MODIS 11-3.7UM
IMAGERY SHOWS FOG HAS DEVELOPED IN THE VALLEYS OF NORTH CENTRAL
PA.
THE PATCHY FOG ACROSS THE EASTERN HALF OF THE STATE SHOULD BURN
OFF BY ARND 13Z BASED ON LATEST 3KM HRRR SFC RH. FURTHER WEST...ARRIVAL
OF MUCH HIGHER DWPTS WILL RESULT IN ONLY SLOW CLEARING FROM EARLY
AM STRATOCU. EXPECT THE LOWS CLOUDS TO LIFT AND BREAK UP TO A BKN
CU FIELD BY AFTN ACROSS THE W MTNS.
GEFS MEAN 925MB TEMPS SUPPORT MAX TEMPS THIS AFTN IN THE L/M70S...WITH
THE WARMEST TEMPS RELATIVE TO NORMAL ACROSS THE W MTNS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
A MAINLY CLEAR SKY AND LIGHT WINDS SHOULD LEAD TO PATCHY VALLEY
FOG LATE TONIGHT. INCREASING LOW LVL MOISTURE ON A LIGHT SOUTHERLY
FLOW SHOULD LEAD TO A MILDER NIGHT WITH MINS FROM THE U40S TO L50S
MOST LOCATIONS.
AN INCREASING SSW FLOW AHEAD OF SHORTWAVE DIVING INTO THE GRT LKS
WILL PUSH PWATS AND 8H TEMPS WELL ABV SEASONAL NORMS ACROSS
WESTERN PA FRIDAY. DIURNAL HEATING OF THIS AIR MASS SHOULD RESULT IN
MARGINAL INSTABILITY ACROSS THE W MTNS BY LATE IN THE
DAY...POSSIBLY SUPPORTING DEVELOPMENT OF A FEW PM TSRA ACROSS THE
ALLEGHENY PLATEAU. SKIES SHOULD RANGE FROM PTSUNNY ACROSS THE W
MTNS...TO SUNNY E OF THE SUSQ RIVER...WHERE LOWER PWAT AIR WILL
LINGER. GEFS MEAN 925 TEMPS RISE ABOUT 2C FROM THOSE OF TDY...SUPPORTING
MAX TEMPS BTWN 75-80F.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
FAIRLY MINOR TIMING DIFFS WITH RESPECT TO FROPA SAT/SAT NIGHT.
LATEST GEFS/SREF AND OPER RUNS SUPPORT RAINFALL BTWN 0.5 AND ONE
INCH OVR MUCH OF THE AREA WITH LOCALLY HIGHER AMTS POSS...AS PLUME
OF ANOMALOUS PWATS WITH GULF OF MEX CONNECTION WORKS ACROSS THE
AREA AHEAD OF CDFRONT. ABUNDANT PRE-FRONTAL CLOUD COVER INDICATED
BY MDL 850-500RH FIELDS AND THIS IS REFLECTED BY PRETTY MEAGER
CAPES SAT AFTN...BUT WILL MAINTAIN SLIGHT CHC OF TSRA FOR NOW.
BY SUNDAY...A MORE PROGRESSIVE UPPER AIR PATTERN IS NOW INDICATED
THAN A DAY AGO...WITH BULK OF MDL DATA PUSHING CDFRONT EAST OF THE
REGION BY EARLY SUNDAY. HAVE TRIMMED POPS BUT KEPT SLIGHT CHC IN
THE FCST FOR SUNDAY TO ACCOUNT FOR HANDFUL OF GEFS MEMBERS WHICH
STILL DEVELOP WAVE ON FRONT AND KEEP SHRA GOING ACROSS EASTERN PA
SUNDAY.
A TRANQUIL WX PATTERN APPEARS TO BE IN STORE FOR CENTRAL PA NEXT
WEEK...AS NEARLY ALL MED RANGE MDL DATA KEEP CENTRAL PA UNDER THE
INFLUENCE OF HIGH PRES AND DRY NORTHERLY FLOW. 925-850MB TEMPS
INDICATE DAYTIME TEMPS SHOULD BE CLOSE TO NORMAL FOR LATE
SEPT...ALTHOUGH SOME COOL NIGHTS APPEAR LIKELY DUE TO DRY AIR AND
PROXIMITY OF SFC HIGH.
&&
.AVIATION /09Z THURSDAY THROUGH MONDAY/...
LIGHT SOUTHERLY FLOW PUSHING AN AREA OF INCREASED LOW LEVEL
MOISTURE NORTHWARD ACROSS W PA. AN AREA OF MVFR CIGS ASSOCIATED
WITH THIS FEATURE WILL WORK INTO KJST-KAOO-KFIG-KBFD DURING THE
PREDAWN HOURS...WITH CIGS DIPPING TO IFR AT KJST FOR A FEW HOURS
BEFORE SUNRISE IN UPSLOPE FLOW. ELSEWHERE...VFR CONDITIONS WILL
CONTINUE EXCEPT FOR LOCALIZED VALLEY FOG.
LOWER CIGS ACROSS PORTIONS OF THE WEST WILL IMPROVE TO VFR SHORTLY
AFTER SUNRISE AS LAYER MIXES...LEAVING A VFR DAY AREAWIDE.
CIG RESTRICTIONS AGAIN LIKELY EARLY FRI MORNING ACROSS THE WEST AS
INCREASING LOW LEVEL SOUTHWEST FLOW CONTINUES MOISTURE TRANSPORT
INTO THE REGION.
OUTLOOK...
FRI...PATCHY AM FOG POSS. OCNL MVFR CIGS ALSO POSS AT KJST-KBFD
IN SCT SHRA/TSRA DURING THE DAY. ELSEWHERE...MAINLY VFR.
FRI NIGHT...PATCHY FOG. LOWERING CIGS ACROSS THE WEST WITH SHOWERS
DEVELOPING AS COLD FRONT APPROACHES.
SAT-SAT NIGHT...COLD FRONT CROSSES REGION. RAIN AND SCT TSTMS WILL
BRING RESTRICTIONS AREAWIDE.
SUN...MVFR CONTINUES IN SCT SHRA/TSRA...ESP SE.
MON...NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD
AVIATION...LAMBERT/CERU
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1039 AM CDT THU SEP 19 2013
.DISCUSSION...12Z UPPER AIR ANALYSIS PLACES AN UPPER LEVEL RIDGE
AXIS OVER THE SOUTHEAST UNITED STATES THIS MORNING.
CONSEQUENTLY...RAIN FREE WEATHER IS OCCURRING ACROSS THE MID SOUTH
WITH ANY CONVECTIVE ACTIVITY OCCURRING THUS FAR OVER THE OHIO
VALLEY AND PORTIONS OF THE UPPER MID WEST AND NORTHERN/CENTRAL
PLAINS. AS OF 10 AM CDT...TEMPERATURES ARE IN THE UPPER 70S TO
AROUND 80 DEGREES AT MOST LOCATIONS.
LATEST SHORT TERM MODEL TRENDS INDICATE THE POTENTIAL FOR SOME
ISOLATED TO PERHAPS SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP
FROM DAYTIME HEATING ACROSS PORTIONS OF THE MID SOUTH...MAINLY
ALONG AND WEST OF THE MISSISSIPPI RIVER WHERE BETTER LOW LEVEL
MOISTURE RESIDES. AT THIS TIME...FEEL THE LATEST 3KM HRRR AND RUC
MAY BE HANDLING THE CONVECTIVE POTENTIAL THE BEST. WILL UPDATE
FORECAST TO ADJUST POPS ACCORDINGLY...AND MAKE ADJUSTMENTS TO
TEMPERATURES...CLOUD COVER AND ALL OTHER ELEMENTS AS NEEDED.
UPDATED GRIDS WILL BE AVAILABLE SHORTLY.
CJC
&&
.PREV DISCUSSION... /ISSUED 709 AM CDT THU SEP 19 2013/
DISCUSSION...
UPDATED FOR 12Z AVIATION DISCUSSION
PREV DISCUSSION... /ISSUED 350 AM CDT THU SEP 19 2013/
SKIES ARE MOSTLY CLEAR ACROSS MUCH OF THE FORECAST AREA THIS
MORNING WITH TEMPERATURES RANGING FROM THE MID 60S TO MID 70S.
TODAY SHOULD BE FAIRLY SIMILAR TO YESTERDAY WITH SOME SCATTERED
THUNDERSTORMS FORMING MAINLY DURING THE AFTERNOON HOURS ACROSS THE
NORTHERN HALF OF THE FORECAST AREA. TEMPERATURES WILL REMAIN QUITE
WARM AGAIN TODAY WITH HIGHS IN THE MID 80S TO AROUND 90 DEGREES.
BY TONIGHT...A COLD FRONT WILL BE MOVING THROUGH THE CENTRAL
PLAINS AND INTO SOUTHWEST MISSOURI. AHEAD OF THE FRONT SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO DEVELOP WITH SOME OF THIS ACTIVITY
REACHING MAINLY WESTERN SECTIONS OF THE FORECAST AREA. ON FRIDAY
THE COLD FRONT WILL START MOVING THROUGH ARKANSAS SO THE CHANCE OF
RAIN WILL INCREASE OVER THE FORECAST AREA WITH THE BEST CHANCE OF
THUNDERSTORMS WEST OF THE MISSISSIPPI RIVER.
THIS MODEL RUN SEEMS TO BRING THE COLD FRONT THROUGH THE FORECAST
AREA FASTER THAN PREVIOUS RUNS SO THAT THE FRONT WILL BE JUST
ABOUT OUT OF THE REGION BY SATURDAY MORNING. FRIDAY NIGHT SHOULD
BE QUITE WET AS THE FRONT MOVES THROUGH. ON SATURDAY RAIN CHANCES
WILL DIMINISH FROM NORTHWEST TO SOUTHEAST AS COOLER AND DRIER AIR
BEGIN TO MOVE IN. TEMPERATURES ON SATURDAY WILL BE A FEW DEGREES
COOLER THAN NORMAL WITH HIGHS AROUND 80 DEGREES EXPECTED FOR MUCH
OF THE FORECAST AREA.
BY SATURDAY NIGHT...THE EXTREME SOUTHEAST CORNER OF THE FORECAST
AREA IS THE ONLY AREA THAT MIGHT SEE AN ISOLATED SHOWER. BY SUNDAY
HIGH PRESSURE WILL IN CONTROL OF THE WEATHER FOR MUCH OF THE EASTERN
U.S. INCLUDING THE FORECAST AREA. THIS WILL MEAN ANOTHER PERIOD OF
DRY WEATHER FROM SUNDAY THROUGH WEDNESDAY. TEMPERATURES WILL
REMAIN SLIGHTLY BELOW NORMAL SUNDAY AND MONDAY BUT WINDS SHOULD
BEGIN TO SHIFT TO THE SOUTH BY TUESDAY ALLOWING FOR WARMER AIR TO
RETURN TO THE REGION WITH ABOVE NORMAL TEMPERATURES EXPECTED FOR
TUESDAY AND WEDNESDAY.
ARS
&&
.AVIATION...
12Z TAF CYCLE
VFR CONDS WILL PREVAIL THROUGHOUT THE PERIOD. EXPECT A FEW SHRAS
AND TSRAS TO DEVELOP ACROSS NORTHERN SECTIONS THIS AFTN.
CONSIDERING THE LATEST INFO AND WHAT HAPPENED YESTERDAY NOT
CONFIDENT ENOUGH IN THE AMOUNT OF COVERAGE TO PLACE THE MENTION OF
VCTS AT ANY OF THE TAF SITES. WL INCLUDE A MENTION OF VCSH AT KJBR
AND KMKL. WINDS WILL BE SOUTH AT 8-12 KTS TODAY. TONIGHT...SHRAS
IN ADVANCE OF A COLD FRONT MAY BEGIN MOVING INTO KJBR BY THE END
OF THE PERIOD. WINDS OVERNIGHT WILL BE SOUTH AT 3-8 KTS.
SJM
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 90 72 85 68 / 20 30 70 70
MKL 89 68 85 64 / 20 20 70 70
JBR 89 71 82 63 / 30 30 80 50
TUP 89 68 88 70 / 10 10 40 80
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
851 AM CDT THU SEP 19 2013
.UPDATE...
WARM FRONT WILL CONTINUE TO LIFT NORTHWARD AND AWAY FROM TN TODAY.
MEANWHILE...SFC HIGH WILL ALSO CONTINUE TO MOVE EAST TOWARD THE
ATLANTIC COAST. NO APPRECIABLE UPPER DYNAMICS ARE APPARENT AS THE
UPPER RIDGE AXIS WILL ACTUALLY BE IN CLOSER PROXIMITY TO THE MID
STATE BY LATE THIS AFTERNOON. HOWEVER...SOME WEAK BUT FAVORABLE
CURVATURE AND SHEAR WILL ROTATE ACROSS PORTIONS OF THE AXIS LATER
TODAY. THIS ALL TRANSLATES INTO A SLIGHT CHANCE OF SHOWERS OR
TSTMS ACROSS NORTHERN AREAS.
TEMPERATURES SHOULD BE A FEW DEGREES GREATER THAN YESTERDAY.
THUS...UPPER 80S FOR HIGHS STILL LOOKS REASONABLE. HRRR IN LINE
WITH CURRENT FCST THINKING.
ONLY MOD WILL BE TO RERUN ZONES WHICH WILL AUTOMATICALLY REMOVE
THE PATCHY FOG WORDING.
&&
.PREV DISCUSSION... /ISSUED 614 AM CDT THU SEP 19 2013/
UPDATE...FOR AVIATION.
AVIATION...
12Z TAFS...VFR CONDITIONS ARE EXPECTED THROUGH MOST OF THIS
PERIOD...THE ONLY EXCEPTION WILL BE SOME POSSIBLE EARLY MORNING
MVFR FOG. SURFACE HIGH PRESSURE ALONG THE EAST COAST WILL PRODUCE
A SOUTH FLOW INTO MID TN WITH SCT-BKN CLOUDS. A STRAY SHRA/TSRA
CANNOT BE RULED OUT...BUT PROB TOO LOW TO INCUDE IN TAFS.
13
PREV DISCUSSION... /ISSUED 355 AM CDT THU SEP 19 2013/
DISCUSSION...
FORECAST REASONING WILL LEAN TOWARD A CONSENSUS MODEL SOLUTION
COMPROMISE FOR THE FORECAST PERIOD UNLESS OTHERWISE NOTED.
FORECAST QUANDARIES...PATCHY FOG POTENTIAL THRU THE MID MORNING
HRS TODAY...SHWR/TSTM CHANCES ESPECIALLY IN ASSOCIATION WITH FRONTAL
PASSAGE FRI NIGHT INTO SAT ALONG WITH POTENTIAL OF THIS BRINGING
HEAVY RAINFALL TO THE MID STATE...OVERALL WX PATTERN SAT NIGHT INTO
THE FIRST PART OF NEXT WEEK...AND TEMPS.
WITH MOST OF THE MID STATE EXPERIENCING CLR SKIES THIS MORNING...AND WITH
TEMPS/DEWPOINTS MAINLY IN THE LOW TO MID 60S ALONG WITH CALM WINDS...DO
EXPECT SOME PATCHY FOG TO FORM IN THE USUAL FOG PRONE LOCATIONS AND NEAR
BODIES OF WATER AND LAST THRU THE MID MORNING HRS. OTHERWISE...WITH RIDGING
INFLUENCES STILL DEPICTED BY MODEL CONSENSUS TO BECOME A LITTLE BIT MORE
ENHANCED THRU THE MORNING HRS ON FRI...WILL ONLY INTRODUCE A SLIGHT CHANCE
OF SHWRS LATE MORNING WITH A SLIGHT CHANCE OF SHWRS/TSTMS BY THE AFTERNOON
HRS WITH AFTERNOON HIGH TEMPS BEING AROUND 5 DEGREES OR SO ABOVE SEASONABLE
NORMAL VALUES UNDER PTCLDY SKIES. HIGHS WILL BE IN THE MID TO UPPER 80S...
LOWER 80S PLATEAU. WILL KEEP THE MID STATE DRY TONIGHT AGAIN UNDER PTCDLY
SKIES WITH THE POSSIBILITY OF YET AGAIN PATCHY FOG ACROSS USUAL FOG PRONE
LOCATIONS AND NEAR BODIES OF WATER THRU THE EARLY MORNING HRS...WITH A
SLIGHT CHANCE OF SHWRS/TSTMS ACROSS WRN PORTIONS OF THE MID STATE THRU THE
MID FRI MORNING HRS WITH THAT PATCHY FOG CONTINUING ACROSS CNTRL AND ERN
PORTIONS OF THE MID STATE DURING THIS TIME PERIOD ALSO. LOWS TONIGHT
ARE EXPECTED TO BE IN THE LOW TO MID 60S...AROUND 60 PLATEAU.
STILL LOOKS LIKE A PRONOUNCED UPPER LEVEL TROUGH WILL DEVELOP TO OUR W IN
ASSOCIATION WITH A SFC COLD FRONT...WITH THEN BOTH APPROACH FRI NIGHT AND
THEN MOVE ACROSS THE MID STATE AS THE DAY PROGRESSES ON SAT. GFS SHOWING
A LITTLE BIT MORE ENHANCED LOW LEVEL JET DYNAMICS MAINLY ACROSS SRN AND
ERN/PLATEAU PORTIONS OF THE MID STATE BY SAT MORNING WITH PRECIP WATER
AMOUNTS APPROACHING AND EVEN SLIGHTLY OVER TWO INCHES. IN LOOKING AT OTHER
FORECAST SOUNDINGS...GFS THE MOST AGGRESSIVE HERE WITH PRECIP WATER VALUES
ALONG WITH THE ABOVE MENTIONED LOW LEVEL JET STRUCTURE AND THUS PRODUCING
SOME HIGH QPF VALUES FOR THE MID STATE FRI NIGHT INTO THE FIRST HALF OF SAT.
IN LOOKING AT LATEST WPC QPF FORECAST ALONG WITH THE OTHER MODELS...AM AT
THIS TIME INCLINED TO BE A LITTLE CONSERVATIVE HERE AS THIS SYSTEM IS NOT
EXPECTED TO BRING A SIGNIFICANT FORCING...INSTABILITY...OR TEMP AIRMASS
CONTRAST WITH IT...THUS WILL GO WITH SLIGHTLY LOWER QPF VALUES THRU THIS
TIME PERIOD. HOWEVER...CAN NOT RULE OUT THE HEAVY RAINFALL POTENTIAL...
BUT THINK AT THIS TIME THAT ANY TYPE OF FLOODING WOULD BE LOCALIZED AND
MINOR AT BEST PER HIGH FFG VALUES AND RAINFALL NOT HAVING BEEN RECEIVED
OVER WIDE AREAS DURING THE PAST FEW DAYS AND WHAT IS EXPECTED TO HAPPEN
UP UNTIL FRI NIGHT. HOWEVER...TO GIVE A HEADS UP POTENTIAL ON THIS HEAVY
RAINFALL POSSIBILITY...WILL GO AHEAD AND MENTION IN THE MORNING`S HWO
ISSUANCE. OTHERWISE...HAVE MENTIONED INCREASING CHANCES OF SHWR/TSTMS E TO
W AS THE DAY PROGRESSES ON FRI WITH THE ABOVE MENTIONED LIMITED INSTABILITY
KEEPING ONLY A CHANCE OF TSTMS THRU FRI NIGHT INTO SAT. HAVE INCREASED POPS
TO CAT MOST LOCATIONS AFTER MIDNIGHT FRI NIGHT...LIKELY S AND PLATEAU...AND
WILL CONTINUE THE TREND OF DECREASING CHANCES OF SHWRS/TSTMS W TO E AS THE
DAY PROGRESSES ON SAT. HIGHS ON FRI WILL CONTINUE THE TREND OF 5 DEGREES OR
SO ABOVE SEASONABLE NORMAL VALUES WITH LOWS FRI NIGHT MAINLY IN THE LOW TO
UPPER 60S...WITH HIGHS ON SAT...AS THE FRONT MOVES THRU ALONG WITH THE UPPER
LEVEL TROUGH...NEAR OR ACTUALLY BELOW SEASONABLE NORMAL VALUES WITH HIGHS
MAINLY IN THE MID TO UPPER 70S.
AS FOR SAT NIGHT INTO THE MID PORTION OF NEXT WEEK...THRU THE FIRST PART
OF NEXT WEEK...WILL TREND CLOSE TO CURRENT FORECAST REASONING WITH
A SLIGHT CHANCE TO CHANCE OF SHWRS ACROSS AT LEAST ERN AND PLATEAU COUNTIES
SAT NIGHT...BUT AM LEANING TOWARD KEEPING THE MID STATE DRY ON SUN WITH
RIDGING INFLUENCES BUILDING ACROSS THE MID STATE PROVIDING DRY CONDITIONS
AND A RETURN TOWARD TEMPS NEAR SEASONABLE NORMS. EVEN THOUGH THERE ARE
SOME TIMING DIFFERENCES IN MODELS...UNLIKE AT THIS TIME YESTERDAY...IT
DOES NOT LOOK LIKE ANY OF THE MODELS ARE ADVERTISING ANY TYPE OF CLOSED
UPPER LEVEL LOW DEVELOPMENT BEHIND THE ABOVE MENTIONED FRONTAL SYSTEM THAT
WOULD SUBSTANTIALLY AFFECT THE MID STATE. THE LATEST EURO DOES DEVELOP A
CLOSED LOW ACROSS CNTRL MS BY MON MORNING BUT MOVES IT WELL SOUTH OF THE
MID STATE AND THEN OPENS IT UP BY TUE...POSSIBLY BRINGING SOME WRAP AROUND
ADDITIONAL MOISTURE TO THE MID STATE DURING THE FIRST PART OF NEXT WEEK.
WITH THIS OVERALL...AND MORE LIKELY TO OCCUR...CHANGE IN CONSENSUS MODEL
SOLUTIONS...WILL GO CLOSE TO CURRENT FORECASTED WX CONDITIONS ACROSS THE
MID STATE DURING THIS TIME PERIOD.
31
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
619 AM CDT THU SEP 19 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 317 AM CDT THU SEP 19 2013
MAIN FORECAST CONCERNS ARE ON SHOWERS AND THUNDERSTORMS TODAY INTO
TONIGHT WITH THE POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS THIS
AFTERNOON AND EVENING.
LATEST WATER VAPOR IMAGERY SHOWED A TROUGH DIGGING INTO THE EASTERN
DAKOTAS AND CENTRAL PLAINS...PUSHING EAST TOWARD THE UPPER
MISSISSIPPI RIVER VALLEY. SEVERAL WEAK EMBEDDED SHORTWAVES NOTED IN
SOUTHWEST FLOW OVER THE REGION THIS MORNING. SURFACE OBSERVATIONS
PLACED A COLD FRONT OVER THE EASTERN DAKOTAS MOVING EAST. SHOWERS
AND ISOLATED THUNDERSTORMS WERE OCCURRING EARLY THIS MORNING MAINLY
SOUTH OF INTERSTATE 90.
THE COLD FRONT WILL MOVE INTO THE UPPER MISSISSIPPI RIVER VALLEY
TODAY BRINGING SHOWERS AND THUNDERSTORMS TO THE AREA. MLCAPE VALUES
INCREASE TO 1500 TO 2200 J/KG THIS AFTERNOON AHEAD OF THE COLD
FRONT. 0-6 KM BULK SHEAR VALUES START OFF RATHER WEAK EARLY THIS
AFTERNOON AS THE UPPER TROUGH AND JET STREAK ARE LOCATED WELL
WELL WEST OF THE REGION. HOWEVER...THE TROUGH STARTS TO CATCH UP
TO THE COLD FRONT DURING THE LATE AFTERNOON AND EARLY EVENING
HOURS. 0-6 KM SHEAR STARTS OUT IN THE 20 TO 25 KT RANGE EARLY THIS
AFTERNOON AND THEN INCREASES TO 30 TO 40 KTS DURING THE EARLY
EVENING HOURS. MOST OF THIS SHEAR IS LOCATED IN THE 0-3 KM LAYER
WHICH WOULD FAVOR A LINEAR CONVECTIVE MODE WITH POSSIBLE BOWING
SEGMENTS...CAPABLE OF PRODUCING DAMAGING WINDS. MESOSCALE MODELS
SUCH AS THE SPCWRF AND HIRESARW EAST ARE IN AGREEMENT WITH THIS
CONVECTIVE MODE. THE 0-3 KM SHEAR VECTOR IS INITIALLY ORIENTED
PERPENDICULAR TO THE FRONT BUT THEN TURNS MORE PARALLEL TO IT.
STORMS ALONG OR BEHIND THE FRONT COULD STRUGGLE TO ORGANIZE INTO
LINEAR STRUCTURES IF THEY DEVELOP BEHIND THE LEADING WIND SHIFT
OF THE FRONT. ALSO...CANNOT RULE OUT SOME MARGINALLY SEVERE HAIL
WITH THIS ACTIVITY GIVEN THE HIGHER CAPE VALUES. SHOWERS AND
STORMS WILL CONTINUE ACROSS MUCH OF THE AREA EARLY THIS EVENING
THEN GRADUALLY SHIFT SOUTHEAST LATE TONIGHT AS THE COLD FRONT
PROGRESSES EAST. SHOWERS AND THUNDERSTORMS WILL ALSO SHIFT
SOUTHEAST AND EXIT THE AREA LATE TONIGHT INTO FRIDAY MORNING. PLAN
ON AN UNSEASONABLY WARM DAY ACROSS THE AREA TODAY WITH WARM
SOUTHERLY FLOW. LOOK FOR HIGH TEMPERATURES TO CLIMB INTO THE THE
LOWER TO MID 80S BEFORE THE PRECIPITATION MOVES IN. CANNOT RULE
OUT SOME UPPER 80S OVER NORTHEAST IOWA INTO SOUTHWEST WISCONSIN.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 317 AM CDT THU SEP 19 2013
THE UPPER LEVEL TROUGH SWINGS THROUGH THE FORECAST AREA ON FRIDAY
PRODUCING STRATUS AND SOME STRATOCUMULUS DURING THE AFTERNOON
HOURS...LEADING TO MOSTLY CLOUDY SKIES. FRIDAY WILL BE BREEZY WITH
A TIGHT PRESSURE GRADIENT OVER THE REGION AS HIGH PRESSURE BUILDS
IN FROM THE WEST. THE HIGH WILL THEN MOVE INTO THE AREA FRIDAY
NIGHT INTO SATURDAY MORNING WITH DRY AND QUIET WEATHER EXPECTED.
PLAN ON LOW TEMPERATURES FALLING INTO THE 40S FRIDAY NIGHT...WITH
SOME UPPER 30S POSSIBLE OVER FAVORED COLD SPOTS ACROSS CENTRAL
INTO NORTH CENTRAL WISCONSIN. THE HIGH WILL REMAIN OVER THE AREA
THROUGH THE WEEKEND. HIGH TEMPERATURES ON SATURDAY WILL BE IN THE
60S...WITH OVERNIGHT LOWS FALLING INTO THE UPPER 30S TO LOWER 40S.
THE COLDEST TEMPERATURES WILL BE ACROSS CENTRAL AND NORTH CENTRAL
WISCONSIN WHERE SOME LOWER 30S ARE POSSIBLE. HAVE ADDED FROST TO
THE FORECAST ACROSS THESE AREAS LATE SATURDAY NIGHT INTO EARLY
SUNDAY MORNING. A FROST ADVISORY MAY BE NEEDED ALONG AND NORTH OF
THE INTERSTATE 94 CORRIDOR. THE HIGH WILL START TO SLIDE EAST OF
THE REGION SUNDAY INTO SUNDAY NIGHT AS A TROUGH DEVELOPS OVER THE
PLAINS. SOUTH/SOUTHEAST FLOW WILL SET UP OVER THE REGION USHERING
IN SLIGHTLY WARMER TEMPERATURES FOR SUNDAY. PLAN ON HIGHS IN THE
UPPER 60S TO LOWER 70S. THE NEXT CHANCE FOR RAIN WILL BE MONDAY
NIGHT INTO TUESDAY AS AN UPPER TROUGH SWINGS THROUGH THE UPPER
MISSISSIPPI RIVER VALLEY FROM THE CENTRAL/NORTHERN PLAINS. SURFACE
HIGH PRESSURE LOOKS TO HOLD STRONG OVER THE AREA AND MUCH OF THE
PRECIPITATION THE FORECAST MODELS ARE SHOWING STARTS TO REALLY DRY
UP AS THE TROUGH MOVES INTO THE HIGH. SOUTHERLY FLOW LOOKS TO
CONTINUE OVER THE AREA THROUGH THE MIDDLE OF NEXT WEEK WITH MAINLY
QUIET WEATHER EXPECTED AND TEMPERATURES HOLDING NEAR NORMAL WITH
HIGHS IN THE 70S AND LOWS IN THE 50S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 619 AM CDT THU SEP 19 2013
SCATTERED CONVECTION KEEPS POPPING UP AROUND THE AREA THIS
MORNING IN THE LOW LEVEL JET AND THE ISENTROPIC UP GLIDE OCCURRING
ON THE 305K AND 310K SURFACES. THE 19.09Z RAP SUGGESTS THIS
MOISTURE TRANSPORT AND ISENTROPIC UP GLIDE WILL START TO DIMINISH
AFTER SUNRISE AND EXPECT THAT THE ACTIVITY WILL ALSO START TO
WEAKEN AS THIS OCCURS. WILL INCLUDE A VCTS FOR BOTH SITES FOR A
COUPLE OF HOURS AS THE BEST COVERAGE IS OVER CENTRAL WISCONSIN.
FOCUS THEN TURNS TO THE INCOMING COLD FRONT FOR THE AFTERNOON. THE
19.06Z NAM INDICATES THE MAIN UPPER LEVEL TROUGH WILL STILL BE
BACK ACROSS THE DAKOTAS LATE THIS AFTERNOON BUT THAT THERE WILL BE
A LEAD SHORT WAVE TROUGH AHEAD OF THIS. THIS SHORT WAVE TROUGH WILL
BE COMING WITH THE COLD FRONT AND SHOULD HELP WIDESPREAD SHOWER
AND STORMS DEVELOP DURING THE AFTERNOON. THE 19.08Z ARX LAPS AND
19.07Z HRRR SUGGEST THE CONVECTION WILL START TO IMPACT BOTH SITES
BETWEEN 21Z AND 22Z AND SHOULD LAST FOR A COUPLE OF HOURS UNTIL
THE FRONT COMES THROUGH SWINGING THE WINDS AROUND TO THE NORTHWEST.
THE FORCING FROM THE MAIN SHORT WAVE TROUGH WILL BE BEST RIGHT
BEHIND THE FRONT SO EXPECTING A 2 TO 3 HOUR PERIOD OF SOME POST-
FRONTAL SHOWERS TO OCCUR WITH MVFR CEILINGS. ONCE THIS ACTIVITY
ENDS...DRIER AIR STARTS TO WORK IN TO ALLOW THE CEILINGS TO GO UP
TO VFR FOR THE REMAINDER OF THE PERIOD.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...04
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
320 PM MDT THU SEP 19 2013
.SHORT TERM...AREA OF ELONGATED MID LEVEL POTENTIAL VORTICITY
EXTENDING FROM FAR NORTHEAST COLORADO SOUTHWEST ACROSS THE PLAINS
INTO THE SOUTHERN FOOTHILLS AND PARK COUNTY HEADING EAST. THIS
FEATURE HELPED DEVELOP ISOLATED RAIN SHOWERS...WITH A FEW
THUNDERSTORMS OVER SOUTH PARK AND SOUTHERN FOOTHILLS. RAINFALL HAD
BEEN LIGHT...LESS THAN A TENTH OF AN INCH. THIS ACTIVITY WAS
SHIFTING EAST WITH THE POTENTIAL VORTICITY. LATEST SATELLITE
SHOWING A DECENT BACK EDGE OF THE MOISTURE WITH DRIER AIR MOVING
SOUTH. MODELS SHOW THIS FEATURE CONTINUING TO SHIFT EAST INTO THE
EVENING...WITH THE LATEST HRRR AND RAP SHOWING ALL THE
PRECIPITATION EAST OF THE AREA BY MIDNIGHT. THIS SEEMS REASONABLE
BASED ON THE CURRENT TRENDS. WILL KEEP A SLIGHT CHANCE OF STORMS
ACROSS PARK COUNTY AND SOUTHERN FOOTHILLS AND PALMER DIVIDE THIS
EVENING. THE NAM SEEMS A BIT SLOWER IN SHIFTING THE PRECIPITATION
EASTWARD...WILL LEAN TOWARD THE HRRR AND RAP SOLUTIONS. AFTER
MIDNIGHT...LOW LEVEL SOUTHEAST WINDS COULD BRING SOME LOW LEVEL
MOISTURE BACK INTO THE FOOTHILLS. THIS SHOWN BY FORECAST
SOUNDINGS. WILL INCREASE CLOUD COVER A BIT...ESPECIALLY ACROSS
LINCOLN COUNTY. OVERNIGHT TEMPERATURES TO COOL INTO THE 40S ACROSS
NORTHEAST COLORADO WITH MOUNTAIN VALLEYS NEAR OR BELOW FREEZING.
ON FRIDAY...UPPER RIDGE OVER GREAT BASIN SHIFTS EAST WITH THE AXIS
ALONG THE COLORADO WESTERN BORDER. NORTHWEST FLOW ALOFT WILL
CONTINUE TO SPREAD DRIER AND MORE SUBSIDENT AIR ACROSS THE THE
AREA. CLOUDS SHOULD DECREASE DURING THE MORNING WITH MAINLY SUNNY
CONDITIONS BY THE AFTERNOON. TEMPERATURES ACROSS THE PLAINS TO
WARM INTO THE LOWER AND MIDDLE 70S.
.LONG TERM...A PAIR OF WEATHER SYSTEMS WILL MOVE ACROSS THE
STATE...ONE ON SUNDAY AND ANOTHER LATE NEXT WEEK. IN THE
MEANTIME...DRY AND SEASONABLE TEMPERATURES WILL PREVAIL. THE GFS
AND ECMWF MODELS ARE IN GOOD AGREEMENT AS THESE WELL DEFINED
TROUGHS TRAVERSE ACROSS THE WESTERN UNITED STATES. SATURDAY WILL
BE WARM AND SUNNY WHILE SUNDAY WILL BE A TRANSITION AHEAD OF THE
APPROACHING SYSTEM. PRECIPITATION SHOULD SPREAD INTO THE MOUNTAINS
BY SUNDAY AFTERNOON AND THEN MOVE ACROSS THE PLAINS SUNDAY NIGHT.
TEMPERATURES COULD DROP COLD ENOUGH FOR A CHANCE OF SNOW ABOVE
11000 FEET AS THE SYSTEM MOVES THROUGH. BEYOND SUNDAY...A RETURN
TO WESTERLY FLOW ALOFT WILL BRING WARM TEMPERATURES AND DRY
WEATHER BACK TO THE FORECAST AREA. NEXT FRIDAY MAY BE THE NEXT
TIME THE FORECAST AREA SEES ANY PRECIPITATION. AT THIS TIME...THE
SYSTEM LOOKS A BIT STRONGER THAN THE FIRST SYSTEM OVER THIS
WEEKEND.
&&
.AVIATION...NORTHEAST TO EAST WINDS TO SHIFT TO THE SOUTHEAST BY
00Z AS SURFACE HIGH MOVE SOUTH ACROSS THE EASTERN PLAINS. MODELS
CONTINUE TO SHOW SOME LOW LEVEL MOISTURE SPREADING NORTH AFTER
06Z. CEILINGS OF 4000 TO 6000 FEET AGL STILL EXPECTED TO DEVELOP
BETWEEN 07Z AND 13Z. SOUTHEAST SURFACE WINDS TO CONTINUE THROUGH
THE DAY FRIDAY AS DRIER AIR SPREADS OVER THE AREA. SHOULD SEE
CEILINGS IMPROVE AFTER 13Z.
&&
.HYDROLOGY...LINGERING SHOWERS AND A FEW THUNDERSTORMS ACROSS
SOUTH PARK AND SOUTHERN FOOTHILLS WILL COME TO AN END AROUND
MIDNIGHT AS DRIER AIR MOVES INTO THE REGION. ANY RAINFALL AMOUNTS
WILL BE LIGHT. NO SHOWERS OR STORMS EXPECTED FRIDAY.
RIVER LEVELS HAVE FLATTENED AND WILL GRADUALLY RECEDE OVER THE
NEXT FEW DAYS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
FLOOD WARNING CONTINUES FOR THE SOUTH PLATTE RIVER FROM
KERSEY TO THE NEBRASKA STATE LINE.
&&
$$
SHORT TERM...D-L
LONG TERM....DANKERS
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS PUEBLO CO
338 PM MDT THU SEP 19 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 317 PM MDT THU SEP 19 2013
FAIRLY MEAGER CONVECTION OUT THERE SO FAR WITH DEW POINTS
STRUGGLING TO REBOUND ALONG THE NORTHERN PORTIONS OF THE AREA
BEHIND THIS MORNING`S COLD FRONT. THEY ARE SLOWLY CREEPING UP INTO
THE LOWER 40S TO MID 40S ACROSS EL PASO AND PUEBLO COUNTIES AS
WINDS SWING AROUND FROM THE EAST THIS AFTERNOON. FARTHER
EAST...DEW POINTS AT KLHX AND KLAA ARE STILL HOVERING IN THE 50S.
THUS HIGHEST MIXED LAYER CAPES OFF OF SPC MESO ANALYSIS IS RUNNING
AROUND 1000 J/KG ACROSS THE SOUTHEAST PLAINS SOUTH OF HIGHWAY
50...BUT THERE APPEARS TO BE A LITTLE CIN TO OVERCOME YET OUT THAT
WAY. AS THE UPPER TROF TRAILS ACROSS THE AREA THIS EVENING...SHORT
RANGE HIGH RES MODELS (LOCAL 4KM WRF...HRRR AND NAM12) ALL SHOW A
WINDOW FOR SOME ISOLATED SHOWERS AND THUNDERSTORMS ACROSS THE
SOUTHEAST MTS/SPREADING INTO THE ADJACENT PLAINS THROUGH THE
EVENING. WITH FORCING STILL COMING THROUGH ITS HARD TO ARGUE.
HOWEVER...HAVE NOTICED TREND IN HRRR TO DECREASE COVERAGE OF QPF
ACROSS THE SOUTHERN I-25 CORRIDOR WITH EACH RUN. AFTER MIDNIGHT
THINK MOST OF THE ACTIVITY WILL BE DONE...HOWEVER...LOW LEVEL
WINDS SWING AROUND FROM THE SOUTHEAST AND MODEL SOUNDINGS BECOME
DEEPLY SATURATED SUGGESTING POTENTIAL FOR LOTS OF LOW
CLOUDS...FOG...AND EVEN PATCHY DRIZZLE ALONG THE SOUTHERN SLOPES
OF THE PALMER DIVIDE WHERE UPSLOPE WILL BE MAXIMIZED. HAVE THROWN
IN SOME ISOLATED -SHRA AND DRIZZLE FOR THE LATE NIGHT/EARLY
MORNING HOURS ALONG WITH AREAS OF FOG ALONG THE I-25 CORRIDOR.
STRATUS WILL SLOWLY CLEAR ON FRIDAY...THOUGH THINK THAT SOUTHERN
SLOPES OF THE PALMER DIVIDE/COLORADO SPRINGS AREA MAY HANG ON TO
CLOUD COVER THROUGH THE MORNING BEFORE BREAKS START TO APPEAR IN THE
AFTERNOON...AS IS THE TYPICAL PATTERN FOR SOUTHERLY UPSLOPE CASES.
OTHERWISE...MODELS KEEP FORECAST AREA DRY FRIDAY AFTERNOON...WITH SE
PLAINS REMAINING CAPPED. TEMPERATURES SHOULD BE ABOUT A CATEGORY COOLER THAN
THOSE OF TODAY. -KT
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 317 PM MDT THU SEP 19 2013
GENERALLY WARM AND DRY WEATHER STILL ON TRACK FOR THE EXTENDED...WITH
JUST A COUPLE OF STORM SYSTEMS TO CONTEND WITH. THE WEEKEND STARTS
OUT WARM AND DRY. SHOULD SEE 80S OVER THE PLAINS BOTH SAT AND SUNDAY.
GFS MOS CONTINUES TO LOOK TOO WARM FOR THE PLAINS...SO HAVE STAYED ON
THE COOL SIDE OF GUIDANCE...PARTICULARLY SUNDAY AS HIGH CLOUDS START
MOVING IN FROM THE WEST.
SOME MODEL DISCREPANCIES FOR OUR FIRST SHORT WAVE LATE SUNDAY. THE TREND
HAS BEEN TOWARDS A SLIGHTLY DEEPER OR SHARPER TROUGH...WHICH THE
ECMWF HAS BEEN ADVERTISING FOR A WHILE NOW. THE GFS NOW LOOKS
COOLER AND WETTER...AND WOULD BRING SEVERAL INCHES OF SNOW TO THE AREA
ABOVE 9K FEET SUNDAY NIGHT. THE NAM IS CONSIDERABLY WARMER AND
PROBABLY WOULD JUST LEAD TO TRACE SNOW AMOUNTS. THE TRUTH LIKELY IS
SOMEWHERE IN BETWEEN...BUT PROBABLY CLOSER TO THE GFS. SHOULD KNOW
BETTER BY TOMORROW OR FRIDAY IF THE NAM MOVES TOWARD A COOLER
SOLUTION. HAVE BUMPED UP POPS ABOUT 10-20 PERCENT AREA WIDE AS THE
TROUGH MOVES THROUGH SUN NIGHT.
MONDAY AND TUESDAY...THINGS REALLY DRY OUT IN ZONAL FLOW...AND WE
SHOULD SEE SOME REAL PLEASANT FALL WEATHER WITH LOTS OF SUNSHINE
AND TEMPS IN THE 70S-NR 80 FOR THE LOWLANDS AND 60S FOR THE HIGHER
VALLEYS. POPS ESSENTIALLY NIL EVEN FOR THE MTS.
NEXT SYSTEM BEGINS TO TAKE SHAPE ON WED THROUGH THU AS A DEEPER TROUGH
MOVES THROUGH THE PACNW AND INTO THE INTER-MOUNTAIN REGION. STILL PLENTY
OF UNCERTAINTY WITH THE TIMING AND DEPTH OF THIS LOW...BUT THE
TREND FOR A WHILE NOW HAS BEEN FOR IT TO LIFT INTO THE NRN ROCKIES
BY LATE THU OR FRI...WHICH WOULD BRING MOST OF THE PRECIP N OF OUR
CWA AND LEAVE US IN A DRY AND BREEZY CORNER. CERTAINLY DOES NOT
LOOK LIKE A BIG STORM FOR OUR AREA...BUT THE MTS SHOULD SEE AT
LEAST SOME LIGHT SNOWFALL ABOVE 9 OR 10K FEET AS H7 TEMPS DROP
CLOSE TO ZERO BY THE END OF THE WEEK. ROSE
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 317 PM MDT THU SEP 19 2013
ISOLATED SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS THE
MOUNTAINS AND SPREAD OFF INTO THE ADJACENT PLAINS DURING THE
AFTERNOON AND EARLY EVENING. THE MAIN THREAT WITH THUNDERSTORMS
WILL BE SOME BRIEF MODERATE RAINFALL AND WIND GUSTS TO AROUND 40
KTS...AS WELL AS LIGHTNING. OVERNIGHT...WINDS ACROSS THE PLAINS
WILL SHIFT AROUND FROM THE SOUTHEAST WITH WIDESPREAD STRATUS AND
AREAS OF FOG AND PATCHY DRIZZLE DEVELOPING ALONG THE LOWER EASTERN
SLOPES OF THE SOUTHEAST MTS AND I-25 CORRIDOR AFTER 06Z. EXPECT
IFR TO LIFR CIGS/VIS FOR KCOS AND KPUB TO DEVELOP AFTER 06Z WITH
THE LOWEST CIGS/VIS ACROSS SOUTHERN EL PASO COUNTY INCLUDING KCOS.
CIGS WILL BE SLOW TO BREAK ACROSS THE SE PLAINS ON
FRIDAY...PARTICULARLY FOR KCOS DUE TO PERSISTENT SOUTHERLY FLOW.
CIGS MAY LIFT INTO THE MVFR TO IFR CATEGORY AROUND 18Z...BEFORE
CLEARING AFTER THAT. KALS WILL REMAIN UNDER VFR CONDITIONS THROUGH
THE NIGHT. THERE IS A LOW PROBABILITY FOR A REPEAT THREAT FOR FOG
OVERNIGHT AT KALS...BUT CHANCES LOOK TOO LOW TO WARRANT MENTION IN
TAFS AT THIS POINT. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...KT
LONG TERM...ROSE
AVIATION...KT
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1034 AM MDT THU SEP 19 2013
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 310 AM MDT THU SEP 19 2013
COLD FRONT IS NOW LOCATED ALONG I-70 AND IS EXPECTED TO CONTINUE
DROPPING SEWRD TO NEAR THE SAN JUAN MOUNTAINS BEFORE WASHING OUT.
THE UPPER LEVEL TROUGH IS LAGGING BEHIND THE SFC FRONT AND IS JUST
ENTERING WRN CO AT THIS HOUR. AHEAD OF THE TROUGH...RADAR PICKING
UP SOME RETURNS N OF I-70 WITH A FEW STRAY STORMS ALSO FORMING
THANKS TO UPPER LEVEL SUPPORT AND OROGRAPHIC LIFT. EXPECT THIS TO
CONTINUE THROUGH DAYBREAK WITH SOME MIDLEVEL CLOUDS AROUND THE
AREA FOR THE COMMUTE TO WORK. 00Z NAM12 SHOWED SOME VERY ISOLD
SHOWERS OVER CENT/SRN MTNS THIS AFTERNOON DUE TO LIMITED MOISTURE
AND SOME OROGRAPHICS WHILE 06Z NAM12 HAS ALL BUT REMOVED THEM.
LATEST HRRR AND RAP13 GUIDANCE ALSO SHOWING A DISTINCT LACK OF
PRECIP FOR THE ENTIRE CWA TODAY. NOT SOLD ON IDEA THOUGH AS SOME
MARGINAL INSTABILITY EXISTS ALONG WITH SOME MOISTURE IN LOWER
LEVELS. FOR NOW...WILL LEAVE ISOLD CONVECTION IN FORECAST FOR THE
HIGHEST TERRAIN IN THE SAN JUANS AND CENTRAL MTNS. MOST AREAS
TODAY WILL SEE SUN...SUN...AND MORE SUN AND MORE FALL LIKE
TEMPERATURES AS A PATTERN SHIFT FINALLY SETS UP.
ANY LINGERING SHOWER OR STORM NEAR THE CENTRAL OR SOUTHERN DIVIDE
WILL QUICKLY DIMINISH THIS EVENING WITH SUNSET. WEAK WARM ADVECTION
ALOFT THEN COMMENCES TONIGHT AS A PROGRESSIVE UPPER RIDGE
APPROACHES...BUT IT WILL NOT LIKELY BE ENOUGH TO OFFSET RADIATIONAL
COOLING DUE TO CLEAR SKIES AND DRIER AIR. HENCE...A COOL NIGHT LOOKS
IN STORE WITH POCKETS OF FREEZING OR NEAR FREEZING TEMPS TO THE
LOWER VALLEYS IN THE CRAIG AND MEEKER AREAS AND WILL CONTINUE THE
FREEZE WATCH FOR THESE AREAS TONIGHT. MODELS SUGGEST THAT THE
STEAMBOAT VALLEY AND AROUND GUNNISON WILL BOTTOM OUT IN THE MID 30S.
TEMPS SHOULD WARM QUICKLY FRIDAY MORNING WITH PLENTY OF SUNSHINE.
DRY AND SUNNY CONDITIONS ARE EXPECTED FRIDAY WITH HIGH TEMPS
REBOUNDING AS THE UPPER RIDGE SLIDES ACROSS THE AREA. AFTERNOON
HUMIDITIES WILL DROP INTO THE TEENS FRIDAY AFTERNOON IN MANY OF THE
NORTHWEST AND WEST-CENTRAL COLORADO VALLEYS...AND EASTERN UTAH
VALLEYS.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 310 AM MDT THU SEP 19 2013
FLOW ALOFT BECOMES SOUTHWEST FRIDAY NIGHT AND SATURDAY AS THE UPPER
RIDGE MOVES TO THE EAST AND A PACIFIC TROUGH PUSHES INLAND. GRADIENT
TIGHTENS SATURDAY AS THE TROUGH ADVANCES FOR STRENGTHENING AND GUSTY
SURFACE WINDS ACROSS NE UT/NW CO SATURDAY AFTERNOON...AND TEMPS
SHOULD WARM OVER FRIDAY. NAM MODEL SHOWS MID-LEVEL MOISTURE BEING
DRAWN NORTHWARD INTO SW CO AS EARLY AS FRI NIGHT WHILE THE GFS WAITS
UNTIL SAT. THE EVENING MODELS ALSO DID SEEM QUITE AS ENTHUSIASTIC
WITH RAISING PRECIPITABLE WATER VALUES AS EARLIER RUNS. STILL...MAY
SEE A FEW SHOWERS OR THUNDERSTORMS OVER THE SAN JUANS SAT AFTERNOON
AND MADE LITTLE CHANGE TO THE CURRENT FORECAST FOR THE FIRST HALF OF
THE WEEKEND.
BIG DIFFERENCE IN LONG-TERM FOR THE WEEKEND AS PREVIOUS GFS RUNS
SHOWED MARGINAL PRECIP WITH AN APPROACHING TROUGH AND SFC COLD
FRONT WHILE LATEST RUN SHOWS SIGNIFICANT PRECIP FOR MUCH OF THE
AREA SUNDAY AFTERNOON AND NIGHT. EC ALSO SHOWING THIS PRECIP WHILE
NAM12 SHOWING VERY LITTLE AT THIS TIME. MOISTURE TRANSPORT VECTORS
ON THE 320K SURFACE DO SHOW SOME MOISTURE STREAMING UP FROM THE
SOUTH SATURDAY NIGHT INTO SUNDAY MORNING BEFORE BEING WORKED ON BY
THE TROUGH. THE TROUGH WILL BE SUPPORTED BY AN 80 KT JET STREAK
AND IT LOOKS LIKE THIS TROUGH MAY BECOME NEGATIVELY TILTED. IF YOU
PUT ALL OF THESE TOGETHER...SOME WIDESPREAD PRECIP CAN BE EXPECTED
WITH SOME STRONG THUNDERSTORMS POSSIBLE. CAN ALSO EXPECT SOME
GUSTY SFC WINDS...ESPECIALLY SUNDAY...AHEAD OF SAID FRONT. SOME
WHITE STUFF ALSO POSSIBLE AT THE HIGHEST ELEVATIONS...ABOVE 13K
FT...AS H7 TEMPS DROP TO AROUND 3C. SFC TEMPERATURES WILL DROP 8
TO 10 DEGREES FROM SATURDAY TO SUNDAY AS THE COLD FRONT PUSHES
THROUGH.
BY MONDAY MORNING...THE TROUGH AND FRONT WILL HAVE EXITED OUR AREA
ALLOWING ZONAL FLOW TO SET UP BRINGING A PERIOD OF DRY WEATHER AND
SEASONAL TEMPERATURES THROUGH WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1034 AM MDT THU SEP 19 2013
VFR CONDITIONS WILL CONTINUE OVER THE REGION THROUGH THE NEXT 24
HOURS AS DRIER AIR BRINGS QUIET WEATHER TO REGION. A FEW
THUNDERSTORMS REMAIN A POSSIBILITY OVER THE RIDGES ALONG THE
CONTINENTAL DIVIDE FROM 19Z THROUGH 01Z FRIDAY. THIS ACTIVITY WILL
RESULT IN BRIEF AND LOCALIZED RIDGE AND PEAK OBSCURATIONS AND
SHOULD NOT AFFECT AIRPORT FLIGHT OPERATIONS.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR COZ002.
UT...NONE.
&&
$$
SHORT TERM...TGR/JAD
LONG TERM...JAD/TGR
AVIATION...NL
AREA FORECAST DISCUSSION
NWS MIAMI FL
227 PM EDT THU SEP 19 2013
.SHORT TERM (TONIGHT-SATURDAY NIGHT)...
THIS EVENING...THE LATEST RADAR SCAN SHOWED SCATTERED ACTIVITY
DEVELOPING OVER THE INTERIOR AREAS SPREADING WESTWARD TOWARD THE
GULF COAST. THE LATEST HRRR MODEL RUNS LINE UP WELL WITH THIS AND
INDICATE THIS ACTIVITY BECOMING FOCUSED OVER AND AROUND THE GULF
COAST AREAS THROUGH THE LATE AFTERNOON AND EVENING HOURS ONCE AGAIN.
CONSIDERING THE EXTENSIVE RAINFALL COVERAGE OVER THE GULF COAST
YESTERDAY...THE MAIN CONCERN THROUGH THIS EVENING WILL BE THE
POTENTIAL FOR ADDITIONAL HEAVY RAINFALL AND FLOODING DUE TO THE
SATURATED GROUNDS.
FRIDAY THROUGH SATURDAY NIGHT...THE LATEST NUMERICAL GUIDANCE
REMAINS IN DECENT AGREEMENT THROUGH THIS PERIOD AND SHOWS WHAT IS
LEFT OF THE WEAKENING BOUNDARY OR TROUGH CURRENTLY MOVING INTO
THE AREA CONTINUING SOUTH WITH SOME DRIER AIR FILLING IN BEHIND IT
FROM THE NORTH. THIS COMBINED WITH THE MEAN LOW-LEVEL FLOW UP TO
10 KFT SHIFTING TO THE NORTH WILL TRANSLATE TO LOWER RAINFALL
CHANCES EACH DAY. DEWPOINTS COULD REACH THE LOWER 60S ACROSS
PORTIONS OF THE INTERIOR AREAS SATURDAY AFTERNOON. MODEL SOUNDINGS
INDICATE PRECIPITABLE WATER VALUES DIPPING DOWN TO AROUND 1.3"
ACROSS PORTIONS OF THE AREA BY SATURDAY. TEMPERATURES ARE FORECAST
TO REMAIN AROUND NORMAL THROUGH THIS PERIOD...WITH THE EXCEPTION
BEING THE POSSIBILITY OF REACHING THE UPPER 60S ACROSS THE
NORTHERN INTERIOR AREAS BY DAYBREAK SATURDAY MORNING.
.LONG TERM (SUNDAY-WEDNESDAY)...
AN UPPER TROUGH IS FORECAST TO DIG ACROSS THE SOUTHEAST AND
EASTERN SEABOARD THROUGH THE SECOND HALF OF THE WEEKEND. OUT AHEAD
OF THIS...SURFACE AND LOW LEVEL FLOW WILL SHIFT TO THE
SOUTH...BRINGING A SURGE OF MOISTURE BACK INTO SOUTH FLORIDA ON
SUNDAY. MODELS HAVE BEEN TRENDING TOWARDS A WEAKER LOW LEVEL/SURFACE
REFLECTION ACROSS THE SOUTHEAST...AND THUS A WEAKER COLD FRONT
MOVING INTO THE SOUTHEAST STATES. THE ECMWF IS NOW STRONGER THAN THE
GFS WITH THE BAROCLINIC SURFACE LOW ACROSS THE NORTHERN GULF
COAST/SOUTHEAST STATES...AND DRAWS THE MOISTURE FROM THE BAY OF
CAMPECHE SYSTEM TO THE NORTHEAST. REGARDLESS...SINCE THE MODELS HAVE
TRENDED SLOWER WITH THE COLD FRONT AND KEEP IT ACROSS NORTH FLORIDA
THROUGH EARLY NEXT WEEK...THE FOCUS FOR STORMS MAY BE ACROSS THE
GULF WATERS AND NORTH OR CENTRAL FLORIDA. WITH NO FOCUS FOR RAINFALL
ACROSS SOUTH FLORIDA AND EXTENSIVE CLOUD COVER POSSIBLY LIMITING
RAINFALL AMOUNTS DURING THE DAY MONDAY AND TUESDAY...THE HEAVIEST
RAINS MAY ACTUALLY FALL OVER THE NIGHT TIME HOURS AS SPEED/COASTAL
CONVERGENCE SETS UP. THE GFS AND ECMWF ARE HINTING AT THIS AS
WELL. SO RAINFALL CHANCES WILL LIKELY REMAIN HIGH SUNDAY THROUGH
TUESDAY. THE FORECAST IS UNCLEAR BEYOND THAT POINT...BUT RAINFALL
CHANCES WILL REMAIN ELEVATED THROUGH AT LEAST WEDNESDAY.
&&
.AVIATION...
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL CONTINUE TO
DEVELOP THROUGH THE AFTERNOON ACROSS THE INTERIOR AND MOVE TOWARDS
KAPF WITH A FEW SHOWERS ALONG THE EAST COAST. SEA BREEZES ALONG BOTH
COASTS UNTIL EARLY THIS EVENING. MOST CONVECTION SHOULD DIMINISH BY
00Z WITH DRIER AIR MOVING INTO THE AREA THROUGH EARLY FRIDAY.
&&
.MARINE...
LIGHT TO MODERATE NORTHEAST WINDS WILL CONTINUE THROUGH SATURDAY AS
A WEAKENING FRONTAL BOUNDARY SHIFTS SOUTH INTO THE AREA. WINDS WILL
SHIFT TO THE SOUTH THROUGH THE SECOND HALF OF THE WEEKEND AND INTO
EARLY NEXT WEEK AS ANOTHER FRONTAL BOUNDARY APPROACHES FROM THE
NORTH. SEAS OVER THE ATLANTIC WATERS SHOULD BEGIN TO SUBSIDE OVER
THE WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 75 88 74 88 / 20 20 10 10
FORT LAUDERDALE 76 88 77 89 / 20 20 10 10
MIAMI 76 89 75 89 / 20 20 10 10
NAPLES 73 90 73 90 / 30 20 10 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...85/AG
AVIATION/RADAR...30/KOB
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
109 PM CDT THU SEP 19 2013
.DISCUSSION...
338 AM CDT
THE FORECAST CHALLENGES ARE CENTERED ON THE NEXT 36 HOURS AS
AN UNSEASONABLY WARM AND MOIST AIR MASS FOR LATTER SEPTEMBER IN
PLACE WILL KEEP THE POTENTIAL FOR STORMS THROUGH TODAY AND AID IN
ACTIVITY ALONG A COLD FRONT MOVING THROUGH LATER TONIGHT AND
FRIDAY.
THIS MORNING...PESKY MCV IS CENTERED OVER NORTHERN IN THIS
MORNING AFTER ITS 18-24 HOUR EASTWARD TRACK OF TROUBLE FROM
CENTRAL IA YESTERDAY MORNING. THE STORM ACTIVITY OF YESTERDAY AND
LAST NIGHT KEPT THE LOW-LEVEL WARM FRONT FROM DEVELOPING TOO
QUICKLY NORTHWARD...SO THAT IS ROUGHLY ANALYZED FROM A 1001MB LOW
ACROSS EASTERN SD THROUGH SOUTHERN MN AND INTO THE WESTERN AND
SOUTHERN FORECAST AREA. WARM AIR ADVECTION INDUCED ASCENT NORTH OF
THIS HAS ONCE AGAIN SPARKED CONVECTION IN THE FAST PACED WSW MID-
LEVEL FLOW EARLY THIS MORNING...THIS TIME ACROSS SW WI/NE IA/NW
IL. A SUBTLE SHORT WAVE IS NOTED IN WATER VAPOR AND ANALYZED BY
HIGH RES MODELS AS WELL. AS THE LOW-LEVEL JET AND ASSOCIATED
MOISTURE TRANSPORT VEER EASTWARD THIS MORNING...SOME OF THIS
ACTIVITY SHOULD FEED ON INSTABILITY AND TRAVERSE THE FORECAST AREA
AHEAD OF THE WAVE. AMDAR SOUNDING FROM ROCKFORD EARLY THIS MORNING
SHOWED 1300 J/KG OF ELEVATED CAPE WHEN LIFTING FROM 850MB...SO
SOME FUEL THERE FOR STORMS AND POSSIBLY A COUPLE STRONGER ONES
CAPABLE OF SMALL HAIL...GUSTY WINDS...AND VERY EFFICIENT RAINFALL.
EXPECT THE ACTIVITY TO MOVE MAINLY EAST OF THE FORECAST AREA BY
LATE MORNING/EARLY AFTERNOON WITH WARM AIR ADVECTION CLOUDS
SCATTERING.
THIS AFTERNOON...THE THERMAL RIDGE AHEAD OF THE SYSTEM COLD FRONT
DEVELOPS NORTHEAST OVER THE AREA THIS PERIOD AND IS ROBUST FOR
THIS TIME OF YEAR...WITH 850MB TEMPERATURES OF 18C-20C FROM EAST
TO WEST ACROSS THE CWA. LOCAL CLIMATOLOGY SUPPORTS HIGHS AROUND
90...OR IN OTHER WORDS WITHIN 5F OF RECORD HIGHS FOR TODAY. SOME
OF THE MORNING CLOUDS...ESPECIALLY ACROSS THE NORTHEAST FORECAST
AREA WHERE THEY MAY LAST THE LONGEST...WILL HINDER THAT SOME.
OTHERWISE GOING FORECAST HIGHS CONTINUE TO LOOK GOOD AND ARE
SUPPORTED BY SOME OF THE BEST VERIFYING GUIDANCE ON WARM DAYS
WITHIN THIS PAST MONTH. IF STORMS FESTER FOR LONGER THIS
MORNING AND CONTINUE INTO AFTERNOON...THEN GOING FORECAST IS TOO
HIGH BY SEVERAL DEGREES. WHILE MLCAPES ARE FORECAST TO BUILD TO
2000-2500 J/KG ACROSS THE CWA LIKELY ERODING CIN BY MID TO LATE
AFTERNOON...THE FOCUS OF PRE-FRONTAL CONVERGENCE AND SHORT WAVE
ENERGY STILL MAINLY LOOKS TO BE AFTER 00Z. BUT THIS IS A HIGH PWAT
WARM SECTOR WITH LIMITED CAPPING AND AS YESTERDAY SHOWED...EVEN
SOMETHING SUBTLE CAN CAUSE PROBLEMS. SO START INCHING UP POPS IN
THE WESTERN CWA LATE THIS AFTERNOON. IF STORMS CAN MAKE IT IN THAT
EARLY...SCATTERED SEVERE POTENTIAL IS THERE GIVEN JUST THE
INSTABILITY AND PWATS.
TONIGHT AND FRIDAY...THE SURFACE LOW WILL DEVELOP NORTHEASTWARD
INTO ONTARIO TONIGHT STEERING THE COLD FRONT INTO THE WESTERN
FORECAST AREA LIKELY BY AROUND DAYBREAK FRIDAY. FOCUS FOR
CONVECTION REMAINS GOOD...ESPECIALLY FOR THE WESTERN FORECAST AREA
THIS EVE INTO EARLY OVERNIGHT. A SCATTERED SEVERE THREAT EXISTS
EVEN WITH MARGINAL DEEP LAYER SHEAR. MUCH LIKE YESTERDAY...THE
THREATS FROM LIKELY MULTI-CELL OR SOMEWHAT LINEAR ACTIVITY THAT
COULD REACH SEVERE LIMITS WOULD BE VERY HEAVY RAINFALL...GUSTY
WINDS...AND HAIL. SOME INDICATION IN BOTH THE 19.00 NAM AND GFS
THAT THE BEST DEEP CONVERGENCE SORT OF SPLITS THE EASTERN FORECAST
AREA AS THE BOUNDARY ADVANCES...AND SEVERAL CONVECTIVE ALLOWING
GUIDANCE MEMBERS DO SHOW A GENERAL DECREASE IN REFLECTIVITY INTO
THE OVERNIGHT. THINK THAT MAY BE A LITTLE TOO EAGER TO DIMINISH
CONVECTION GIVEN THE PWATS AT TWO STANDARD DEVIATIONS ABOVE NORMAL
AND A WELL-DEFINED COLD FRONT MOVING INTO THAT AIR MASS. SO STILL
HAVE MAINTAINED HIGH POPS EVEN FURTHER EAST LATE INTO THE NIGHT
AND INTO FRIDAY MORNING. DID ADD MENTION OF HEAVY RAIN IN THE
WESTERN FORECAST AREA GIVEN THE HIGH LIKELIHOOD OF RAIN IN A MOIST
AND REPLENISHING AIR MASS. THANKFULLY THAT AREA DID NOT RECEIVE
THE HIGHER RAIN YESTERDAY. A REGENERATION OF STRONGER CONVECTION
ON FRIDAY LOOKS POSSIBLE...BUT MAINLY EAST OF THE FORECAST AREA ON
THE MEAN OF MODEL GUIDANCE. COULD SEE A LITTLE SLOW DOWN
AGAIN...BUT AT THIS POINT NOT TOO CONCERNED ON A SEVERE THREAT
FRIDAY IN OUR CWA. MORE SO IT WOULD STILL BE THE HEAVY RAIN
POTENTIAL. MILD TEMPERATURES TONIGHT LOOK TO CLIMB TO THE MID 70S
TO 80 ON FRIDAY AS THE COLD AIR ADVECTION ENSUES ALOFT.
SATURDAY AND BEYOND...GIVEN ACTIVE SHORT TERM WEATHER HAVE GONE
WITH A SMART CONSENSUS BLEND DURING THIS TIME. WITH 850MB
TEMPERATURES FORECAST BY THE NAM/GFS/EC OF 3C-5C OVER LAKE MI...SOME
LAKE EFFECT CLOUDS ARE LIKELY SATURDAY NIGHT INTO EARLY SUNDAY
INTO NW IN/NE IL AS THE WINDS VEER NNE OVER THE LAKE. OVER LAND
SATURDAY NIGHT CONDITIONS SHOULD BE CLOSER TO CALM. SO THAT SPELLS
WHAT COULD BE QUITE AN IMPRESSIVE TEMPERATURE CONTRAST ACROSS
CHICAGOLAND AND HAVE THAT AT ALMOST 20F IN THE FORECAST SUNDAY
MORNING...WITH LOWS AROUND 39F IN AURORA WHILE 58F DOWNTOWN
CHICAGO. THE SURFACE HIGH MOVES EASTWARD EARLY NEXT WEEK WITH VERY
GRADUALLY DEVELOPING WARM AIR ADVECTION. TEMPERATURES ARE FORECAST
TO INCH UP A COUPLE DEGREES EACH DAY.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* MAIN CONCERN IS TIMING AND EXTENT OF ADDITIONAL CONVECTION
TODAY...HOPING IT HOLDS OFF UNTIL AFTER EVENING RUSH.
* IN THE SHORT TERM THE WINDS SHOULD BE TURNING SOUTHWEST AND
INCREASING BUT EFFECTS OF EARLIER CONVECTION ARE STILL BEING FELT.
* LINGERING MVFR VSBY EXPECTED TO IMPROVE SHORTLY.
LENNING
//DISCUSSION...UPDATED 18Z...
CONVECTION THAT MOVED THROUGH THIS MORNING HAS EXITED THE
TERMINALS TO THE EAST. SATELLITE PICS AND UPSTREAM OBS SUGGEST
CONDITIONS SHOULD BE IMPROVING RAPIDLY EARLY THIS AFTERNOON BEFORE
ADDITIONAL CONVECTION DEVELOPS WITH AN APPROACHING COLD FRONT THIS
EVENING. THERE IS A CHANCE OF SEEING SOME TSRA DEVELOPMENT THIS
AFTERNOON EARLIER THAN DEPICTED IN THE 18Z TAFS...BUT FCST MODELS
MATCH LATEST RADAR TRENDS IN KEEPING THE BULK OF THE ACTIVITY
ALONG OR BEHIND THE FRONT WHICH ARRIVES WELL AFTER MIDNIGHT.
UNFORTUNATELY THINGS COULD START SLOW AGAIN TOMORROW MORNING
BEFORE PRECIP COMES TO AN END WITH POSTFRONTAL WINDS VEERING
NORTHWEST AND SKIES IMPROVING.
LENNING
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM CONFIDENCE OF NOT SEEING ADDITIONAL TSRA BEFORE FRONTAL
TSRA ARRIVES TONIGHT.
* MEDIUM TO HIGH CONFIDENCE OF IMPROVING CONDITIONS AND SOUTHWEST
WINDS THIS AFTERNOON.
* MEDIUM CONFIDENCE ON TIMING AND EXTENT OF ACTIVITY TONIGHT.
LENNING
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT THROUGH WEDNESDAY...VFR. WX NIL.
KREIN
&&
.MARINE...
300 AM CDT
AN AREA OF LOW PRESSURE CENTERED OVER THE EASTERN DAKOTAS WILL
WEAKEN SLIGHTLY AND TRACK NORTHEAST TO WESTERN ONTARIO BY THIS
EVENING. SOUTHERLY WINDS TO AROUND 25 KT WILL PERSIST OVER THE
LAKE AS THE THE LOW DEEPEN FURTHER AND TRACKS NORTHEAST INTO
NORTHERN QUEBEC BY SATURDAY MORNING. AN ASSOCIATED COLD FRONT WILL
SWEEP ACROSS LAKE MICHIGAN FRIDAY AFTERNOON AND EVENING...WITH
WINDS GRADUALLY VEERING FROM SOUTHWESTERLY TO NORTHWESTERLY
AND...ULTIMATELY NORTHEASTERLY...AS A LARGE AREA OF HIGH PRESSURE
BUILDS IN BEHIND THE FRONT. IN THE COLD ADVECTION BEHIND THE
FRONT...NORTHWEST TO NORTH WINDS WILL REDEVELOP...WITH SOME
OCCASIONAL GUSTS TO 30KT POSSIBLE FRIDAY NIGHT.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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Area Forecast Discussion
National Weather Service Lincoln IL
1250 PM CDT Thu Sep 19 2013
.DISCUSSION...
ISSUED 1040 AM CDT Thu Sep 19 2013
Warm front has lifted well to the northeast of central Illinois
this morning, leaving behind partly to mostly sunny skies and very
warm temps in the upper 70s and lower 80s. Convection continues to
fire along the edge of the strengthening cap in the warm sector,
mainly from southern Lake Michigan S/SE across Indiana into the
Ohio River Valley. As warm air aloft spreads further east, this
activity will continue to shift further away from Illinois this
afternoon. End result will be a hot and mainly dry day, with
perhaps a few isolated thunderstorms. Afternoon high temps will
reach the upper 80s and lower 90s. Better thunderstorm chances
will arrive by late evening across the Illinois River Valley.
Latest HRRR shows a line of convection developing along an
advancing cold front and pushing toward the Illinois River by
around 03z. This activity should continue eastward in a weakening
state overnight.
Barnes
&&
.AVIATION...
ISSUED 1250 PM CDT Thu Sep 19 2013
Southwesterly winds gusting to around 20kt will prevail at the
KILX terminals throughout the afternoon before subsiding to around
10kt by sunset. Will see a gradual increase in mid-level
cloudiness, with BKN conditions expected by around 00z. Forecast
soundings remain rather dry through the evening before an
advancing cold front comes into the picture toward midnight. HRRR
brings scattered showers/thunder into the Illinois River Valley
after 04z...while NAM and 4km WRF-NMM are similar. All models tend
to develop a vigorous line of convection with the front late this
afternoon/early this evening well west of the Mississippi River,
then weaken it considerably as it pushes into central Illinois
overnight. For that reason, have decided to limit the convection
in the 18z TAFs. Will carry a tempo group for thunder at only KPIA
between 07z and 11z...with just predominant showers and VCTS
further east at the remaining terminals late tonight into Friday
morning. Winds will remain southwesterly overnight, then will veer
to west-northwest after FROPA Friday morning.
Barnes
&&
.PREV DISCUSSION...
ISSUED 251 AM CDT Thu Sep 19 2013
Developing storm system over the northern Plains to be the main
issue for the forecast in the Midwest for this package. High
pressure over the Atlantic seaboard slowly sliding eastward with
southerly flow ramping up over the region in the middle of the
country. Sunshine and WAA will send temperatures well above normal
ahead of the storm system. All the warm air in place will provide
instability for advancing chances of thunderstorms through tonight
and tomorrow. Biggest issues for the forecast revolve around the
timing of the front vs. max heating, and speed of the front
itself. Ongoing convection already starting to hint that the
mesoscale influences with prefrontal trofs and outflow boundaries
will more than likely complicate the forecast of the details. Best
chances for precip tonight and through tomorrow.
SHORT TERM...Today and tomorrow...
Hot today with the ridge expanding into the Midwest. Warmest
midlevels in western CWA but will likely be countered somewhat by
advancing clouds. However, front will hold off enough to see upper
80s over majority of the area. Cold front has slowed progression
to tomorrow but convection ahead of the front and associated cold
pools will mask some of the distinction of the leading edge.
Plenty of instability in the region...but the cold front being
delayed a bit results in the FA barely clipped by the slight risk
outlook to the northwest for tonight. Frontal progression tomorrow
to be slower, and already in rain and cloud cover from the overnight
will likely inhibit intense storm development. So far tomorrow
remains in a general thunder. Overnight Friday will see a clearing
from west to east. Will need to keep an eye on guidance NW of
Interstate 55 corridor for rapid clearing may result in a need for
an adjustment of the lows down a couple degrees.
LONG TERM...Saturday through Wednesday...
Milder weather and dry through the extended. High pressure
dominates the eastern half of the country and temperatures remain
milder and closer to normal...with heat building again under a
thermal ridge in the southwestern US. With southwesterly flow
kicking in next week Tues, the extended could see some warmer
temps as time draws nearer should the pattern persist. Guidance
is still being pulled to 70s by climatology at this point.
HJS
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1121 AM CDT THU SEP 19 2013
.DISCUSSION...
338 AM CDT
THE FORECAST CHALLENGES ARE CENTERED ON THE NEXT 36 HOURS AS
AN UNSEASONABLY WARM AND MOIST AIR MASS FOR LATTER SEPTEMBER IN
PLACE WILL KEEP THE POTENTIAL FOR STORMS THROUGH TODAY AND AID IN
ACTIVITY ALONG A COLD FRONT MOVING THROUGH LATER TONIGHT AND
FRIDAY.
THIS MORNING...PESKY MCV IS CENTERED OVER NORTHERN IN THIS
MORNING AFTER ITS 18-24 HOUR EASTWARD TRACK OF TROUBLE FROM
CENTRAL IA YESTERDAY MORNING. THE STORM ACTIVITY OF YESTERDAY AND
LAST NIGHT KEPT THE LOW-LEVEL WARM FRONT FROM DEVELOPING TOO
QUICKLY NORTHWARD...SO THAT IS ROUGHLY ANALYZED FROM A 1001MB LOW
ACROSS EASTERN SD THROUGH SOUTHERN MN AND INTO THE WESTERN AND
SOUTHERN FORECAST AREA. WARM AIR ADVECTION INDUCED ASCENT NORTH OF
THIS HAS ONCE AGAIN SPARKED CONVECTION IN THE FAST PACED WSW MID-
LEVEL FLOW EARLY THIS MORNING...THIS TIME ACROSS SW WI/NE IA/NW
IL. A SUBTLE SHORT WAVE IS NOTED IN WATER VAPOR AND ANALYZED BY
HIGH RES MODELS AS WELL. AS THE LOW-LEVEL JET AND ASSOCIATED
MOISTURE TRANSPORT VEER EASTWARD THIS MORNING...SOME OF THIS
ACTIVITY SHOULD FEED ON INSTABILITY AND TRAVERSE THE FORECAST AREA
AHEAD OF THE WAVE. AMDAR SOUNDING FROM ROCKFORD EARLY THIS MORNING
SHOWED 1300 J/KG OF ELEVATED CAPE WHEN LIFTING FROM 850MB...SO
SOME FUEL THERE FOR STORMS AND POSSIBLY A COUPLE STRONGER ONES
CAPABLE OF SMALL HAIL...GUSTY WINDS...AND VERY EFFICIENT RAINFALL.
EXPECT THE ACTIVITY TO MOVE MAINLY EAST OF THE FORECAST AREA BY
LATE MORNING/EARLY AFTERNOON WITH WARM AIR ADVECTION CLOUDS
SCATTERING.
THIS AFTERNOON...THE THERMAL RIDGE AHEAD OF THE SYSTEM COLD FRONT
DEVELOPS NORTHEAST OVER THE AREA THIS PERIOD AND IS ROBUST FOR
THIS TIME OF YEAR...WITH 850MB TEMPERATURES OF 18C-20C FROM EAST
TO WEST ACROSS THE CWA. LOCAL CLIMATOLOGY SUPPORTS HIGHS AROUND
90...OR IN OTHER WORDS WITHIN 5F OF RECORD HIGHS FOR TODAY. SOME
OF THE MORNING CLOUDS...ESPECIALLY ACROSS THE NORTHEAST FORECAST
AREA WHERE THEY MAY LAST THE LONGEST...WILL HINDER THAT SOME.
OTHERWISE GOING FORECAST HIGHS CONTINUE TO LOOK GOOD AND ARE
SUPPORTED BY SOME OF THE BEST VERIFYING GUIDANCE ON WARM DAYS
WITHIN THIS PAST MONTH. IF STORMS FESTER FOR LONGER THIS
MORNING AND CONTINUE INTO AFTERNOON...THEN GOING FORECAST IS TOO
HIGH BY SEVERAL DEGREES. WHILE MLCAPES ARE FORECAST TO BUILD TO
2000-2500 J/KG ACROSS THE CWA LIKELY ERODING CIN BY MID TO LATE
AFTERNOON...THE FOCUS OF PRE-FRONTAL CONVERGENCE AND SHORT WAVE
ENERGY STILL MAINLY LOOKS TO BE AFTER 00Z. BUT THIS IS A HIGH PWAT
WARM SECTOR WITH LIMITED CAPPING AND AS YESTERDAY SHOWED...EVEN
SOMETHING SUBTLE CAN CAUSE PROBLEMS. SO START INCHING UP POPS IN
THE WESTERN CWA LATE THIS AFTERNOON. IF STORMS CAN MAKE IT IN THAT
EARLY...SCATTERED SEVERE POTENTIAL IS THERE GIVEN JUST THE
INSTABILITY AND PWATS.
TONIGHT AND FRIDAY...THE SURFACE LOW WILL DEVELOP NORTHEASTWARD
INTO ONTARIO TONIGHT STEERING THE COLD FRONT INTO THE WESTERN
FORECAST AREA LIKELY BY AROUND DAYBREAK FRIDAY. FOCUS FOR
CONVECTION REMAINS GOOD...ESPECIALLY FOR THE WESTERN FORECAST AREA
THIS EVE INTO EARLY OVERNIGHT. A SCATTERED SEVERE THREAT EXISTS
EVEN WITH MARGINAL DEEP LAYER SHEAR. MUCH LIKE YESTERDAY...THE
THREATS FROM LIKELY MULTI-CELL OR SOMEWHAT LINEAR ACTIVITY THAT
COULD REACH SEVERE LIMITS WOULD BE VERY HEAVY RAINFALL...GUSTY
WINDS...AND HAIL. SOME INDICATION IN BOTH THE 19.00 NAM AND GFS
THAT THE BEST DEEP CONVERGENCE SORT OF SPLITS THE EASTERN FORECAST
AREA AS THE BOUNDARY ADVANCES...AND SEVERAL CONVECTIVE ALLOWING
GUIDANCE MEMBERS DO SHOW A GENERAL DECREASE IN REFLECTIVITY INTO
THE OVERNIGHT. THINK THAT MAY BE A LITTLE TOO EAGER TO DIMINISH
CONVECTION GIVEN THE PWATS AT TWO STANDARD DEVIATIONS ABOVE NORMAL
AND A WELL-DEFINED COLD FRONT MOVING INTO THAT AIR MASS. SO STILL
HAVE MAINTAINED HIGH POPS EVEN FURTHER EAST LATE INTO THE NIGHT
AND INTO FRIDAY MORNING. DID ADD MENTION OF HEAVY RAIN IN THE
WESTERN FORECAST AREA GIVEN THE HIGH LIKELIHOOD OF RAIN IN A MOIST
AND REPLENISHING AIR MASS. THANKFULLY THAT AREA DID NOT RECEIVE
THE HIGHER RAIN YESTERDAY. A REGENERATION OF STRONGER CONVECTION
ON FRIDAY LOOKS POSSIBLE...BUT MAINLY EAST OF THE FORECAST AREA ON
THE MEAN OF MODEL GUIDANCE. COULD SEE A LITTLE SLOW DOWN
AGAIN...BUT AT THIS POINT NOT TOO CONCERNED ON A SEVERE THREAT
FRIDAY IN OUR CWA. MORE SO IT WOULD STILL BE THE HEAVY RAIN
POTENTIAL. MILD TEMPERATURES TONIGHT LOOK TO CLIMB TO THE MID 70S
TO 80 ON FRIDAY AS THE COLD AIR ADVECTION ENSUES ALOFT.
SATURDAY AND BEYOND...GIVEN ACTIVE SHORT TERM WEATHER HAVE GONE
WITH A SMART CONSENSUS BLEND DURING THIS TIME. WITH 850MB
TEMPERATURES FORECAST BY THE NAM/GFS/EC OF 3C-5C OVER LAKE MI...SOME
LAKE EFFECT CLOUDS ARE LIKELY SATURDAY NIGHT INTO EARLY SUNDAY
INTO NW IN/NE IL AS THE WINDS VEER NNE OVER THE LAKE. OVER LAND
SATURDAY NIGHT CONDITIONS SHOULD BE CLOSER TO CALM. SO THAT SPELLS
WHAT COULD BE QUITE AN IMPRESSIVE TEMPERATURE CONTRAST ACROSS
CHICAGOLAND AND HAVE THAT AT ALMOST 20F IN THE FORECAST SUNDAY
MORNING...WITH LOWS AROUND 39F IN AURORA WHILE 58F DOWNTOWN
CHICAGO. THE SURFACE HIGH MOVES EASTWARD EARLY NEXT WEEK WITH VERY
GRADUALLY DEVELOPING WARM AIR ADVECTION. TEMPERATURES ARE FORECAST
TO INCH UP A COUPLE DEGREES EACH DAY.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* CONVECTION MOSTLY WINDING DOWN...WITH WINDS TO VEER AND INCREASE.
* MVFR CIGS AND IFR VSBYS FOR A BIT LONGER THIS MORNING.
* ADDITIONAL TSRA TOWARD EVENING WITH AN APPROACHING FRONT.
LENNING
//DISCUSSION...UPDATED 12Z...
PRIMARY CONCERNS THROUGH THE PERIOD WILL BE PERIODIC CHANCES FOR
ADDITIONAL SHRA/TSRA AND SLY-SSWLY WINDS GUSTING TO 20-25 KT.
THE REGION REMAINS UNDER WARM/MOIST ADVECTION WITH SLY FLOW AT THE
SFC AND SWLY FLOW THROUGH THE LOWEST 10KFT ABOVE THE SFC LAYER.
WHILE THE STRONGEST WARM ADVECTION AND ISENTROPIC LIFT REMAINS TO
THE WEST...OVER THE UPPER MISSOURI VALLEY TO THE MIDDLE
MISSISSIPPI VALLEY. THE BROAD AREA OF WARM ADVECTION AND LIFT WILL
KEEP THE CHANCES FOR SCT THUNDER OVER THE AREA FOR THE NEXT FEW
HOURS...HOWEVER...GIVED THE LACK OF A SPECIFIC FOCUSING
MECHANISM...THE ACTIVITY WILL BE SCATTERED AND LIKELY WILL NOT
IMPACT THE TERMINALS FOR A SOLID BLOCK OF TIME. SO...WILL KEEP THE
VCSH AND TEMPO GROUPS IN THE FORECAST...BUT CONFIDENCE REMAINS LOW
AS TO THE EXACT TIMING OF DIRECT IMPACT ON THE TERMINALS. THE
OTHER SIGNIFICANT CHANCE FOR THUNDER WILL COME THIS EVENING AND
THROUGH THE NIGHT AS A COLD FRONT MOVES THROUGH THE REGION. FOR
THE EVENING HOURS...THE ACTIVITY...ONCE AGAIN...WILL LIKELY BE
MORE SCATTERED...BUT AS THE COLD FRONT APPROACHES...THE ACTIVITY
SHOULD SOLIDIFY WITH A PERIOD OF PREVAILING THUNDER LIKELY. AT
THIS POINT...THE BEST CHANCE FOR PREVAILING THUNDER SHOULD BE JUST
AFTER MIDNIGHT AND INTO THE EARLY MORNING HOURS. THERE SHOULD THEN
BE A PERIOD OF SOME TRAILING STRATIFORM RAIN WITH LOWER END MVFR
OR POSSIBLY IFR CIGS DEVELOPING FOR THE PRE-DAWN HOURS.
FOR WINDS...THERE IS LITTLE CHANGE TO THE GOING FORECAST. WINDS
SHOULD REMAIN SLY THROUGH THE MORNING AT ARND 10KT...AWAY FROM
THUNDER. SOME LOCALLY HIGHER GUSTS ARE POSSIBLY INVOF THUNDER. WITH
DAYTIME WARMING AND SOME BREAKING UP OF CLOUD COVER...HIGHER GUSTS
SHOULD MIX DOWN TO THE SFC AND FREQUENT GUSTS TO ARND 20KT SHOULD
PREVAIL FROM LATE MORNING THROUGH EARLY EVENING. AS THE FRONTAL
TROUGH APPROACHES THE MISSISSIPPI RIVER LATER TODAY...WIND
DIRECTION SHOULD VEER A LITTLE WEST OF SOUTH TO 200-210 DEGREES
BEFORE SHIFTING TO NWLY WITH THE FROPA.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE OF MOSTLY DRY THIS AFTERNOON UNTIL FRONTAL
PRECIP ARRIVES TOWARD EVENING.
* MEDIUM CONFIDENCE IN CIG/VSBY IMPROVEMENTS.
* MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS.
LENNING
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT THROUGH WEDNESDAY...VFR. WX NIL.
KREIN
&&
.MARINE...
300 AM CDT
AN AREA OF LOW PRESSURE CENTERED OVER THE EASTERN DAKOTAS WILL
WEAKEN SLIGHTLY AND TRACK NORTHEAST TO WESTERN ONTARIO BY THIS
EVENING. SOUTHERLY WINDS TO AROUND 25 KT WILL PERSIST OVER THE
LAKE AS THE THE LOW DEEPEN FURTHER AND TRACKS NORTHEAST INTO
NORTHERN QUEBEC BY SATURDAY MORNING. AN ASSOCIATED COLD FRONT WILL
SWEEP ACROSS LAKE MICHIGAN FRIDAY AFTERNOON AND EVENING...WITH
WINDS GRADUALLY VEERING FROM SOUTHWESTERLY TO NORTHWESTERLY
AND...ULTIMATELY NORTHEASTERLY...AS A LARGE AREA OF HIGH PRESSURE
BUILDS IN BEHIND THE FRONT. IN THE COLD ADVECTION BEHIND THE
FRONT...NORTHWEST TO NORTH WINDS WILL REDEVELOP...WITH SOME
OCCASIONAL GUSTS TO 30KT POSSIBLE FRIDAY NIGHT.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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Area Forecast Discussion
National Weather Service Lincoln IL
1040 AM CDT Thu Sep 19 2013
.DISCUSSION...
ISSUED 1040 AM CDT Thu Sep 19 2013
Warm front has lifted well to the northeast of central Illinois
this morning, leaving behind partly to mostly sunny skies and very
warm temps in the upper 70s and lower 80s. Convection continues to
fire along the edge of the strengthening cap in the warm sector,
mainly from southern Lake Michigan S/SE across Indiana into the
Ohio River Valley. As warm air aloft spreads further east, this
activity will continue to shift further away from Illinois this
afternoon. End result will be a hot and mainly dry day, with
perhaps a few isolated thunderstorms. Afternoon high temps will
reach the upper 80s and lower 90s. Better thunderstorm chances
will arrive by late evening across the Illinois River Valley.
Latest HRRR shows a line of convection developing along an
advancing cold front and pushing toward the Illinois River by
around 03z. This activity should continue eastward in a weakening
state overnight.
Barnes
&&
.AVIATION...
ISSUED 655 AM CDT Thu Sep 19 2013
An area of showers and thunderstorms associated with a small MCS will
mainly stay east of the central IL terminal airports this morning
from Vermilion county ese into Indiana. Carried VCSH over eastern
IL airports til 14-15Z with light fog/haze bringing visibilities
of 4-6 miles. Isolated convection possible this afternoon and
early evening as airmass become more unstable, but coverage too
limited to pinpoint down in the TAFs. VFR conditions should
generally prevail today and this evening with scattered cumulus
clouds and scattered-broken mid level clouds. A cold front
extending from 1001 mb low pressure over se part of Lake Winnipeg
through western MN thru far nw corner of IA into se Nebraska and
nw KS. Cold front slated to push se to near the IL river by PIA
around 12Z/7 am Fri. A band of showers and thunderstorms to
accompany the cold front and spread se across central IL
overnight, reaching PIA after 05Z/midnight and DEC and CMI after
09Z/4 am. MVFR ceilings and visibilities possible with convection
overnight. SSW winds around 10 kts early this morning to increase
to 10-15 kts with gusts 18-23 kts by 15Z and continue through
early evening, then be 10-14 kts tonight and gradually veer sw
overnight.
07
&&
.PREV DISCUSSION...
ISSUED 251 AM CDT Thu Sep 19 2013
Developing storm system over the northern Plains to be the main
issue for the forecast in the Midwest for this package. High
pressure over the Atlantic seaboard slowly sliding eastward with
southerly flow ramping up over the region in the middle of the
country. Sunshine and WAA will send temperatures well above normal
ahead of the storm system. All the warm air in place will provide
instability for advancing chances of thunderstorms through tonight
and tomorrow. Biggest issues for the forecast revolve around the
timing of the front vs. max heating, and speed of the front
itself. Ongoing convection already starting to hint that the
mesoscale influences with prefrontal trofs and outflow boundaries
will more than likely complicate the forecast of the details. Best
chances for precip tonight and through tomorrow.
SHORT TERM...Today and tomorrow...
Hot today with the ridge expanding into the Midwest. Warmest
midlevels in western CWA but will likely be countered somewhat by
advancing clouds. However, front will hold off enough to see upper
80s over majority of the area. Cold front has slowed progression
to tomorrow but convection ahead of the front and associated cold
pools will mask some of the distinction of the leading edge.
Plenty of instability in the region...but the cold front being
delayed a bit results in the FA barely clipped by the slight risk
outlook to the northwest for tonight. Frontal progression tomorrow
to be slower, and already in rain and cloud cover from the overnight
will likely inhibit intense storm development. So far tomorrow
remains in a general thunder. Overnight Friday will see a clearing
from west to east. Will need to keep an eye on guidance NW of
Interstate 55 corridor for rapid clearing may result in a need for
an adjustment of the lows down a couple degrees.
LONG TERM...Saturday through Wednesday...
Milder weather and dry through the extended. High pressure
dominates the eastern half of the country and temperatures remain
milder and closer to normal...with heat building again under a
thermal ridge in the southwestern US. With southwesterly flow
kicking in next week Tues, the extended could see some warmer
temps as time draws nearer should the pattern persist. Guidance
is still being pulled to 70s by climatology at this point.
HJS
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
107 PM EDT THU SEP 19 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 355 AM EDT THU SEP 19 2013
AN UPPER RIDGE WILL BE ACROSS CENTRAL INDIANA THROUGH THIS EVENING
AS WARM MOIST AND UNSTABLE AIR MOVES IN FROM THE SOUTH ON THE BACK
SIDE OF SURFACE HIGH PRESSURE ACROSS THE EASTERN STATES. THERE IS A
CHANCE OF THUNDERSTORMS MAINLY THIS AFTERNOON AND EVENING AS WEAK
WAVES MOVE OVERTOP THE RIDGE AND THE ATMOSPHERE BECOMES VERY
UNSTABLE. THUNDERSTORMS WILL BECOME WIDESPREAD FRIDAY AND FRIDAY
NIGHT AS A COLD FRONT DROPS SOUTHEAST ACROSS CENTRAL INDIANA FRIDAY
NIGHT. THERE COULD BE A FEW LINGERING MORNING THUNDERSTORMS SATURDAY
MORNING ACROSS SOUTHEASTERN PARTS OF CENTRAL INDIANA.
OTHERWISE...HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT ALLOW FOR
COOLER TEMPERATURES AND DRY WEATHER THROUGH THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /REST OF TODAY AND TONIGHT/...
ISSUED AT 1008 AM EDT THU SEP 19 2013
.UPDATE...
NUMEROUS SHOWERS AND THUNDERSTORMS WILL LAST THROUGH MIDDAY AND...
AND INTO EARLY AFTERNOON OVER EASTERN SECTIONS OF THE REGION. RAPID
REFRESH THIS CONVECTION UNTIL MID AFTERNOON OVER THE EAST. AFTER
THAT WILL CONTINUE WITH THE SCENARIO THAT THUNDERSTORMS WILL DIMINISH
BY LATE AFTERNOON PER NAM AND RAPID REFRESH MODELS. IN REGARDS TO
TEMPERATURES LATEST RAP INDICATES HIGH TEMPERATURES APPROACHING 90
FAR WEST WHERE THERE WILL BE MORE SUNSHINE THIS AFTERNOON TO RAISE
TEMPERATURES. OVER THE EAST CLOUDS AND LINGERING PRECIPITATION MAY
KEEP HIGH TEMPERATURES CLOSER TO 80.
NO CHANGES WILL BE MADE AT THIS TIME TONIGHT. NAM SUGGESTS INDICATES
THERE SHOULD BE A LULL IN ANY THUNDERSTORM ACTIVITY MOST OF TONIGHT
AND THEN CHANCES INCREASING TOWARDS DAYBREAK WEST AS COLD FRONT
APPROACHES.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
ISSUED AT 355 AM EDT THU SEP 19 2013
MAIN CHALLENGE TO THE SHORT TERM WILL CONTINUE TO BE POPS ALONG WITH
TIMING OF SHOWER ACTIVITY OUT OF THE FORECAST AREA. MODELS ARE NOW
IN GOOD AGREEMENT ON FRONTAL TIMING AND WILL GO WITH A BLEND THAT
SUGGESTS THE APPROACHING STRONG NORTHERN UPPER TROUGH WILL FORCE THE
FRONT TO NEAR LAFAYETTE BY 00Z SATURDAY AND THEN SOUTHEAST OF
CENTRAL INDIANA AFTER 09Z SATURDAY. THE SPC DAY2 OUTLOOK AS THROWN
ROUGHLY OUR SOUTHEASTERN HALF OF THE FORECAST IN A SLIGHT RISK OF
SEVERE WEATHER FOR FRIDAY AFTERNOON AND EVENING. THIS SEEMS
REASONABLE AS THE LOW LEVEL JET WILL BE OVER THIS AREA AFTER 18Z
FRIDAY...AND WITH PLENTY OF WIDESPREAD ACTIVITY EXPECTED ACROSS THE
NORTHWEST HALF OF THE FORECAST AREA DURING THE MORNING AND
AFTERNOON...THAT PART OF THE FORECAST AREA WILL HAVE A HARD TIME
DESTABILIZING AS MUCH AS THE SOUTHEAST. EVEN SOUTHEAST...ONLY
EXPECT AN ISOLATED SEVERE STORM OR TWO WITH MARGINAL SHEAR AND
INSTABILITY. WILL GO WITH OCCASIONAL POPS FRIDAY SPREADING SOUTHEAST
DURING THE AFTERNOON AND NIGHT. WILL LEAVE SMALL CHANCE LINGER
SHOWERS SATURDAY MORNING...OTHERWISE...HIGH PRESSURE WILL BUILD IN
BEHIND THE FRONT WHICH WILL BRING DRY WEATHER IN FOR THE REST OF THE
WEEKEND ALONG WITH COOLER TEMPERATURES PER MOS AND MODEL BLEND.
HEAVY RAIN WILL CONTINUE TO BE A THREAT THROUGH FRIDAY NIGHT WITH
PRECIPITABLE WATER VALUES NOT DROPPING MUCH UNTIL OVERNIGHT FRIDAY
NIGHT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
ISSUED AT 355 AM EDT THU SEP 19 2013
DRY FORECAST THIS PERIOD WITH SEASONABLE TEMPERATURES.
GFS AND ECMWF DEPICT A CUT OFF UPPER LOW MOVING THROUGH THE
APPALACHIANS EARLY IN THE PERIOD WHILE RIDGING ALOFT AND STRONG
SUBSIDENCE OVER THE MISSISSIPPI RIVER VALLEY PROVIDES A NORTHERLY
FLOW OF AIR AS IT SLOWLY BUILDS EAST DURING THE PERIOD.
AS THE RIDGE MOVES EAST OVER INDIANA BY THE MIDDLE OF NEXT
WEEK...TEMPS WILL SLOWLY MODERATE TO SLIGHTLY ABOVE NORMAL AS
RETURN FLOW BEGINS.
&&
.AVIATION /DISCUSSION FOR 191800Z TAF ISSUANCE/...
ISSUED AT 1259 PM EDT THU SEP 19 2013
CONVECTION HAS MOVED EAST OF THE SITES AT THIS POINT. WHILE SOME
POP UP DEVELOPMENT IS POSSIBLE YET THIS AFTERNOON/EVENING BOTH
TIMING AND PLACEMENT ARE UNCERTAIN ENOUGH TO LEAVE OUT AT THIS
TIME. MODEL SOUNDINGS SHOW PRETTY GOOD INVERSION AND LOW LEVEL
SATURATION OVERNIGHT BUT WINDS SHOULD STAY BETWEEN 5-10 KTS SO FOR
NOW WILL JUST DROP OUTLYING SITES TO MVFR FOG FOR A FEW HOURS
AFTER 9Z. A COLD FRONT WILL APPROACH TOMORROW AND WILL BRING
THUNDERSTORMS WITH IT BUT EXACT TIMING IS STILL FAR ENOUGH OUT TO
JUST INCLUDE A PROB30 AT THIS TIME. LEFT THIS OUT AT KBMG AS IT
WILL BE BEYOND THE FORECAST PERIOD THERE. ALSO EXPECT TO SEE SOME
WIND GUSTS UP TO AROUND 20 KTS BY MID MORNING OUT OF THE SOUTHWEST AHEAD
OF THE FRONT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MK
NEAR TERM...JH
SHORT TERM...MK
LONG TERM....JAS
AVIATION...CP
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AREA FORECAST DISCUSSION
NWS DODGE CITY KS
223 PM CDT Thu Sep 19 2013
...Updated long term section...
.SYNOPSIS...
ISSUED AT 1206 PM CDT THU SEP 19 2013
At 12z Thursday a -18c 500mb trough was located over the northern
Rockies with a 300mb jet streak extending from the based of this
upper trough into southern Manitoba. Across the panhandle of Texas a
40-50kt jet was observed with the left exit region of this jet
steak located near the Oklahoma panhandle. this related well to
some early morning convection which developed near a surface
trough of low pressure that extended from the panhandle of
Oklahoma into north central Kansas. A surface cold front at 12z
extended from eastern Nebraska, across northwest Kansas into east
central Colorado.
&&
.SHORT TERM...(This evening through Friday)
ISSUED AT 145 PM CDT THU SEP 19 2013
Based on 18z surface analysis the surface cold front was
progressing across western Kansas slightly quicker than what the
12z GFS and 12z NAM suggested. The latest HRRR and RAP seems to be
tracking the front a little better earlier this afternoon so will
follow these models for the frontal location between 21z and 00z.
Convection is expected to begin to initiate near this boundary
late day given the afternoon instability progged and improving
upper level dynamic from the left entrance region of an weak upper
level jet crossing western Oklahoma. The current distribution of
precipitation chances across south central Kansas still looks on
track so other than adjusting the location of the front, no major
adjustments to the previous forecast is anticipated late today and
early tonight. SPC mesoanalysis indicating better 0-6km shear late
today so at this time can not rule the chance of a few
thunderstorms near the Oklahoma border. Quarter size hail, gusty
winds and periods of heavy rainfall currently appear to be the
main hazard late today.
Convection across south central Kansas and near the Oklahoma
border after sunset will taper off towards midnight and skies are
expected to begin to clear from north to south. Lows tonight will
be cooler than the past few nights and based on expected 09z to
12z dewpoints will keep lows mainly in the 50s.
High pressure at the surface will build into western Kansas on
Friday as an upper level ridge builds into the western high plains
from the west. The highs on Friday are expected to climb only into
the mid to upper 70s given that both the NAM and GFS suggest a 3c-
6c decrease in 925mb-850mb temperature from 00z Thursday to 00z
Friday.
.LONG TERM...(Friday night through Thursday)
ISSUED AT 222 PM CDT THU SEP 19 2013
Mostly clear skies and dry conditions are anticipated Friday night
through Sunday morning as an upper level ridge moves over the
Central Plains, mid levels of the atmosphere remain dry, and a dome
of high pressure slides southeast of the area. The only exception to
this will be the possibility of a few cumulus clouds around peak
heating. Winds will generally be from the northeast Friday night
shifting to more of a southerly direction Saturday into Sunday
morning. Meanwhile, an upper level shortwave will be moving through
the Western United States Saturday then into the Central Rockies
Sunday. Mid to upper level moisture will be on the increase during
the day Sunday allowing for a few clouds to form. This shortwave
will also help push a cold front through the area Sunday night. A
few thunderstorms will be possible along and ahead of this front
with winds shifting to more of a southerly direction behind it. Cold
air advection will be short lived with this front as winds shift
back to a southerly direction Monday night through Wednesday. Flow
aloft becomes more zonal (west to east) Monday night through Tuesday
then more of a southwest direction Wednesday as the next shortwave
digs into the Intermountain West. Mostly clear skies and dry
conditions are expected over Western Kansas during this timeframe
with lee troughing strengthening across eastern Colorado.
Seasonable temperatures are expected Saturday with highs around 80
degrees and lows Saturday and Sunday morning in the 50s. Highs are
then expected to reach into the lower 80s Sunday and Monday with mid
80s Tuesday and Wednesday. Lows are forecasted to range from the
upper 50s to mid 60s.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 1206 PM CDT THU SEP 19 2013
The cold front that was located across northwest Kansas at 12z
Thursday was at 17z located just just southeast of Dodge City and
Hays. Gusty north to northwest winds behind this front will
decrease to less than 10kts after sunset as an area of high
pressure at the surface beings to build into the area from
northwest. Cooler and drier air will begin to work its way into
western Kansas overnight but there will be a chance for a brief
period of low VFR cigs between 03z and 06z based on the moisture
profiles from the 12z NAM bufr soundings in the 850-800mb level.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 55 77 51 80 / 20 0 0 0
GCK 53 76 51 81 / 10 0 0 0
EHA 52 75 53 81 / 20 0 0 0
LBL 55 78 52 82 / 40 0 0 0
HYS 52 75 51 81 / 10 0 0 0
P28 60 80 53 80 / 90 10 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Burgert
SHORT TERM...Burgert
LONG TERM...Hovorka_42
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
147 PM CDT Thu Sep 19 2013
...Updated short term discussion...
.SYNOPSIS...
ISSUED AT 1206 PM CDT THU SEP 19 2013
At 12z Thursday a -18c 500mb trough was located over the northern
Rockies with a 300mb jet streak extending from the based of this
upper trough into southern Manitoba. Across the panhandle of Texas a
40-50kt jet was observed with the left exit region of this jet
steak located near the Oklahoma panhandle. this related well to
some early morning convection which developed near a surface
trough of low pressure that extended from the panhandle of
Oklahoma into north central Kansas. A surface cold front at 12z
extended from eastern Nebraska, across northwest Kansas into east
central Colorado.
&&
.SHORT TERM...(This evening through Friday)
ISSUED AT 145 PM CDT THU SEP 19 2013
Based on 18z surface analysis the surface cold front was
progressing across western Kansas slightly quicker than what the
12z GFS and 12z NAM suggested. The latest HRRR and RAP seems to be
tracking the front a little better earlier this afternoon so will
follow these models for the frontal location between 21z and 00z.
Convection is expected to begin to initiate near this boundary
late day given the afternoon instability progged and improving
upper level dynamic from the left entrance region of an weak upper
level jet crossing western Oklahoma. The current distribution of
precipitation chances across south central Kansas still looks on
track so other than adjusting the location of the front, no major
adjustments to the previous forecast is anticipated late today and
early tonight. SPC mesoanalysis indicating better 0-6km shear late
today so at this time can not rule the chance of a few
thunderstorms near the Oklahoma border. Quarter size hail, gusty
winds and periods of heavy rainfall currently appear to be the
main hazard late today.
Convection across south central Kansas and near the Oklahoma
border after sunset will taper off towards midnight and skies are
expected to begin to clear from north to south. Lows tonight will
be cooler than the past few nights and based on expected 09z to
12z dewpoints will keep lows mainly in the 50s.
High pressure at the surface will build into western Kansas on
Friday as an upper level ridge builds into the western high plains
from the west. The highs on Friday are expected to climb only into
the mid to upper 70s given that both the NAM and GFS suggest a 3c-
6c decrease in 925mb-850mb temperature from 00z Thursday to 00z
Friday.
.LONG TERM...(Friday through Wednesday)
ISSUED AT 311 AM CDT THU SEP 19 2013
A deep upper level shortwave trough will be moving out of the
northern and central plains by Friday morning. The associated
surface cold front will be well to the southeast of western
Kansas with clear skies and cooler temperatures in its wake.
The medium range models show a fairly progressive upper level
pattern across North America through the remainder of the extended
period. An upper level ridge will move east over the central High
Plains Saturday and Sunday before another strong shortwave trough
moves out of the Rockies into the central High Plains Sunday
night and Monday. The atmosphere is not progged to be overly
unstable but the GFS and ECMWF both show a 70 knot upper level jet
propagating across the Oklahoma/Texas panhandles Sunday night.
With western Kansas under the left exit region of this jet, think
that the going 30-40 percent pops for thunderstorms looks
reasonable.
Upper level ridging builds back over the central part of the
country through midweek ahead of another strong wave that digs
into the western states. We should see dry weather through midweek
before precipitation chances increase by next weekend.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 1206 PM CDT THU SEP 19 2013
The cold front that was located across northwest Kansas at 12z
Thursday was at 17z located just just southeast of Dodge City and
Hays. Gusty north to northwest winds behind this front will
decrease to less than 10kts after sunset as an area of high
pressure at the surface beings to build into the area from
northwest. Cooler and drier air will begin to work its way into
western Kansas overnight but there will be a chance for a brief
period of low VFR cigs between 03z and 06z based on the moisture
profiles from the 12z NAM bufr soundings in the 850-800mb level.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 55 77 50 80 / 20 0 0 0
GCK 53 76 50 81 / 10 0 0 0
EHA 52 75 52 81 / 20 0 0 0
LBL 55 78 51 81 / 40 0 0 0
HYS 52 75 50 80 / 10 0 0 0
P28 60 80 52 80 / 90 10 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Burgert
SHORT TERM...Burgert
LONG TERM...Gerard
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1122 AM MDT THU SEP 19 2013
.UPDATE...
ISSUED AT 909 AM MDT THU SEP 19 2013
AREA OF PRECIPITATION CONTINUES TO MARCH EAST AHEAD OF A COLD
FRONT THAT HAS MOVED THROUGH THE WEST HALF OF THE AREA SO FAR.
BEST CHANCES FOR RAINFALL CONTINUE TO LOOK TO BE OVER THE FAR EAST
AS LIFT FROM THE COLD FRONT COMBINED WITH AN UPPER LEVEL TROUGH
WILL MOVE THROUGH AROUND NOON. BEHIND THE FRONT NORTHERLY WINDS
HAVE BECOME GUSTY...RANGING FROM 20-30 MPH WITH SOME GUSTS NEARING
40 MPH IN FAR NORTHEAST COLORADO. THE GUSTS SHOULD START TO
DECLINE BY THE EARLY AFTERNOON AS THE SURFACE PRESSURE GRADIENT
BEHIND THE FRONT SLACKENS.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 358 AM MDT THU SEP 19 2013
FORECAST PROBLEMS WILL BE PRECIPITATION CHANCES TODAY...HOW COOL TO
MAKE HIGHS AND LOWS THROUGH FRIDAY NIGHT AND HOW MUCH TO WARM THINGS
UP ON SATURDAY. SATELLITE SHOWING AN ACTIVE FLOW FROM THE PACIFIC
INTO NORTH AMERICA. THE FLOW WAS AMPLIFYING SOME OVER THE PACIFIC...
ESPECIALLY ALONG THE WEST COAST. ONE SYSTEM IS PUSHING EAST ALONG THE
U.S AND CANADIAN BORDER. OUTFLOW FROM THUNDERSTORM CLUSTER TO OUR
NORTH HAS PUSHED THROUGH THE AREA WITH A COLD FRONT APPROACHING FROM
THE NORTHWEST.
AT JET LEVEL...THE SREF WAS DOING A LITTLE BETTER WITH THE JET
DEPICTION OVER OUR AREA. AT MID LEVELS...MODELS WERE HAVING A LITTLE
TROUBLE THE SPEED AND AMPLITUDE OF THE NORTHERN LOW. AT THIS TIME
IT APPEARS THE GFS AND UKMET WERE DOING A LITTLE BETTER THAN THE
ECMWF AND CANADIAN. THE RUC WAS CATCHING THE INITIAL WIND FIELD THE
BEST WITH THE ECMWF NOT TOO FAR BEHIND. THE UKMET AND GFS WERE DOING
A LITTLE BETTER THAN THE OTHER OUTPUT ON THE LOW LEVEL THERMAL
FIELD.
TODAY/TONIGHT...INTERESTING PRECIPITATION FORECAST. INITIAL ROUND OF
THUNDERSTORMS WERE CAUSED BY INITIAL SURFACE TROUGH AND OUTFLOW
BOUNDARY FROM CLUSTER OF THUNDERSTORMS THAT MOVED TO THE NORTH OF OUR
FORECAST AREA. HOWEVER ADDITIONAL DEVELOPMENT IS NOW OCCURRING IN
ADVANCE OF COLD FRONT WHICH IS VERY NEAR THE NORTHWEST CORNER OF THE
FORECAST AREA. ALSO AT THIS TIME...MAIN SHORTWAVE TROUGH ROTATING
AROUND NORTHERN UPPER LOW IS BEGINNING TO MOVE IN FROM THE WEST.
ALSO THE RIGHT REAR QUADRANT OF THE JET IS NEAR/OVER THE WESTERN END
OF THE FORECAST. DURING THE DAY THEY ALL HANDLE IT DIFFERENTLY.
HOWEVER...BY THE END OF THE AFTERNOON INTO THE EARLY AFTERNOON...THE
RIGHT REAR QUADRANT IS OVER OR NEAR THE EASTERN END OF THE AREA. IN
ADVANCE OF ALL THESE FEATURES THERE APPEARS ENOUGH ELEVATED CAPE WITH
FAVORABLE THETA-E LAPSE RATES TO ALLOW FOR A GOOD RESPONSE TO THE
LIFT. AT THIS TIME IT LOOKS LIKE THE FAVORED AREA FOR THUNDERSTORMS
IS ALONG AND EAST OF THE COLORADO BORDER...GETTING HIGHER AS YOU GO
EAST. KEPT THIS GENERAL IDEA FROM THE DAY SHIFT BUT RAISED POPS
SLIGHTLY FURTHER EAST. THUNDERSTORMS LOOK TO BE DONE BY LATE IN THE
DAY.
DEFINITELY LOOKS COOLER. THE QUESTION IS HOW MUCH. THE AMOUNT OF
TEMPERATURE CHANGE OVER YESTERDAY WOULD YIELD SLIGHTLY COOLER
TEMPERATURES THAN WHAT I HAVE IN THERE NOW. DID MAKE SLIGHT
ADJUSTMENTS COOLER IN LINE WITH THE BIAS ADJUSTMENT TO THE 850 MB
TEMPERATURES. THIS TENDED TO BE IN THE MIDDLE OF THE GUIDANCE. WILL
BE A RATHER COOL NIGHT TONIGHT WITH LITTLE CLOUD COVER AND LIGHT
WINDS. MODELS DIFFER ON WHERE THE LIGHTEST WINDS WILL BE. AT THIS
TIME IT LOOKS THEY WILL BE IN THE WESTERN AND NORTHERN SECTIONS AND
ADJUSTED ACCORDINGLY.
FRIDAY/FRIDAY NIGHT...MID/UPPER RIDGE BUILDING INTO THE AREA WILL
MAKE FOR DRY CONDITIONS AND LITTLE TO NO CLOUD COVER. SURFACE RIDGE
JUST PULLING OFF TO THE EAST DURING THE DAY WITH LIGHT AND
VARIABLE WINDS...ESPECIALLY IN THE EAST. MODELS ARE INDICATING
TEMPERATURES NEAR WHAT THEY ARE TO BE TODAY. ONLY MADE SLIGHT
ADJUSTMENTS BASED ON THAT. SOME DIFFERENCES IN HOW COOL TO MAKE THE
MINS. THE NAM STARTS WARM ADVECTION MUCH FASTER WITH THE OTHER MODELS
SLOWER. IT SHOULD BE WARMER BUT AM NOT GOING AS WARM AS THE NAM.
SATURDAY/SATURDAY NIGHT...MID/UPPER LEVEL RIDGE STARTS PUSHING EAST
LATE IN THE DAY AND ESPECIALLY IN THE NIGHT WITH SOUTHWEST FLOW
ALOFT DEVELOPING OVER THE AREA. THIS RIDGE PLUS VERY DRY/WELL MIXED
AIR MASS ALOFT WILL KEEP CONDITIONS DRY...DESPITE THE FACT AN UPPER
JET APPROACHES THE WESTERN PORTIONS OF THE AREA LATE IN THE NIGHT.
SHOULD BE WARMER...QUESTION IS HOW MUCH WARMER. NAM CONTINUES TO BE
THE MOST AGGRESSIVE WITH THIS. WIND FIELD AND CONSENSUS OF 850 MB
TEMPERATURES SUPPORT GOING COOLER. THIS IS CLOSE TO WHAT CURRENT
FORECAST HAS IN THERE AND ONLY MADE SLIGHT ADJUSTMENTS.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 300 AM MDT THU SEP 19 2013
A SHORTWAVE TROUGH WILL QUICKLY MOVE THROUGH SUNDAY NIGHT. THE
STRONGEST FORCING WILL BE NORTH OF THE FORECAST AREA ACROSS NEBRASKA
WHERE GFS ENSEMBLE MEAN QPF VALUES ARE HIGHEST. ISOLATED TO
SCATTERED CONVECTION SHOULD IMPACT THE WESTERN PORTION OF THE
FORECAST AREA BY SUNDAY EVENING AND THEN OVERSPREAD THE REST OF
THE AREA OVERNIGHT. THE GREATEST RAIN CHANCES AND POTENTIAL FOR
THE HIGHEST RAINFALL AMOUNTS WILL BE OVER ROUGHLY THE NORTHEASTERN
HALF OF THE FORECAST AREA. SLIGHTLY COOLER TEMPERATURES WILL
ARRIVE BEHIND THIS SHORTWAVE AND ASSOCIATED COLD FRONT ON MONDAY
BUT COLD AIR ADVECTION IN THE WAKE OF THIS SYSTEM IS BRIEF AND
INSIGNIFICANT. STRONG EAST TO WEST ORIENTED MID/UPPER FLOW WILL BE
SITUATED OVER THE NORTHERN ROCKIES AND NORTHERN PLAINS ON TUESDAY.
BY MID WEEK A LARGE TROUGH EVOLVES OVER THE WESTERN CONUS. MODELS
DIFFER ON HOW THIS TROUGH WILL EVOLVE BY MID WEEK WITH GFS AND
ECMWF DIFFERING ON THE POSITION OF CLOSED UPPER LOW...MEANWHILE
GFS ENSEMBLE MEAN DEPICTS A MORE OPEN/PROGRESSIVE TROUGH. IN
EITHER SCENARIO...SIGNIFICANT IMPACTS TO OUR AREA ARE NOT EXPECTED
THROUGH THE END OF THE EXTENDED PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1119 AM MDT THU SEP 19 2013
VFR CONDITIONS FORECAST FOR THE 18Z TAFS. CURRENT LOW CLOUDS OVER
KGLD WILL MOVE EAST AHEAD OF THE MID LEVEL TROUGH AXIS. GUSTY
WINDS WILL DECLINE GRADUALLY THROUGH EARLY AFTERNOON...BECOMING
LIGHTER BY MID AFTERNOON THEN LIGHT BY EARLY EVENING. THE LIGHT
WINDS WILL CONTINUE THROUGH THE REST OF THE PERIOD DUE TO A
SURFACE HIGH PRESSURE BUILDING OVER THE AREA TONIGHT/FRIDAY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JTL
SHORT TERM...BULLER
LONG TERM...BRB
AVIATION...JTL
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1210 PM CDT Thu Sep 19 2013
...Updated synopsis and aviation discussion...
.SYNOPSIS...
ISSUED AT 1206 PM CDT THU SEP 19 2013
At 12z Thursday a -18c 500mb trough was located over the northern
Rockies with a 300mb jet streak extending from the based of this
upper trough into southern Manitoba. Across the panhandle of Texas a
40-50kt jet was observed with the left exit region of this jet
steak located near the Oklahoma panhandle. this related well to
some early morning convection which developed near a surface
trough of low pressure that extended from the panhandle of
Oklahoma into north central Kansas. A surface cold front at 12z
extended from eastern Nebraska, across northwest Kansas into east
central Colorado.
&&
.UPDATE...
ISSUED AT 844 AM CDT THU SEP 19 2013
Scatted showers and even a few isolated thunderstorms will
continue across western and north central Kansas as an upper level
disturbance based the nam 450mb- 400mb pv lifts northeast across
western Kansas. HRRR appears to have a decent handle on this so
will lean in that direction for precipitation chances through the
early afternoon. Thunderstorms still appear become more widespread
across south central Kansas during the mid to late afternoon as a
cold front moves into south central Kansas, late day instability,
and the location of the left exit region of an upper level jet at
00z Friday. Also trended towards a non diurnal trend in
temperatures this afternoon behind the cold front as it crosses
western Kansas.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 212 AM CDT THU SEP 19 2013
Short range models indicate the upper level trough kicking out of
the Rockies into the Northern Plains today setting up shower and
thunderstorm chances across the Upper Midwest southwestward into the
Central Plains, including portions of central and western Kansas.
As the upper level trough moves into the Dakotas and Nebraska, an
attendant cold front will push southeastward into western Kansas
late this morning into the afternoon. Meanwhile, a +85kt upper level
jet is projected to climb northeast out of the desert southwest into
western and central Kansas from this afternoon into this evening.
Along with more favorable dynamic support aloft, steepening mid
level lapse rates and increased instability will be enough to
support thunderstorm development along and ahead of the cold front
as it begins to push further southeast into more favorable
moisture across central Kansas and eastern portions of southwest
Kansas. Although vertical shear profiles are not exactly ideal,
CAPE values in excess of 2000 J/KG ahead of the front will be
enough to support strong to marginally severe thunderstorms...mainly
southeast of a Hays to Liberal line. The potential for heavy
rainfall exists as well with NAM/GFS model soundings showing PW
values up around 1.5 inches.
Temperatures are expected to climb back up into the lower 90s(F)
across south central Kansas where the frontal passage isn`t likely
to occur until late this afternoon. Otherwise, look for highs up
into the upper 70s(F) and 80s(F) behind the front with the cooler
temperatures across west central Kansas. Lows generally down into
the 50s(F) are likely tonight as much cooler air filters south into
western Kansas overnight.
.LONG TERM...(Friday through Wednesday)
ISSUED AT 311 AM CDT THU SEP 19 2013
A deep upper level shortwave trough will be moving out of the
northern and central plains by Friday morning. The associated
surface cold front will be well to the southeast of western
Kansas with clear skies and cooler temperatures in its wake.
The medium range models show a fairly progressive upper level
pattern across North America through the remainder of the extended
period. An upper level ridge will move east over the central High
Plains Saturday and Sunday before another strong shortwave trough
moves out of the Rockies into the central High Plains Sunday
night and Monday. The atmosphere is not progged to be overly
unstable but the GFS and ECMWF both show a 70 knot upper level jet
propagating across the Oklahoma/Texas panhandles Sunday night.
With western Kansas under the left exit region of this jet, think
that the going 30-40 percent pops for thunderstorms looks
reasonable.
Upper level ridging builds back over the central part of the
country through midweek ahead of another strong wave that digs
into the western states. We should see dry weather through midweek
before precipitation chances increase by next weekend.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 1206 PM CDT THU SEP 19 2013
The cold front that was located across northwest Kansas at 12z
Thursday was at 17z located just just southeast of Dodge City and
Hays. Gusty north to northwest winds behind this front will
decrease to less than 10kts after sunset as an area of high
pressure at the surface beings to build into the area from
northwest. Cooler and drier air will begin to work its way into
western Kansas overnight but there will be a chance for a brief
period of low VFR cigs between 03z and 06z based on the moisture
profiles from the 12z nam bufr soundings in the 850-800mb level.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 85 55 78 50 / 30 30 0 0
GCK 80 53 76 50 / 30 10 0 0
EHA 82 52 76 52 / 40 10 0 0
LBL 85 55 79 51 / 30 20 0 0
HYS 80 52 75 50 / 30 10 0 0
P28 92 60 80 52 / 80 80 10 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Burgert
SYNOPSIS...Burgert
SHORT TERM...JJohnson
LONG TERM...Gerard
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
328 PM EDT THU SEP 19 2013
.SYNOPSIS...
ALTHOUGH SHOWERS ARE POSSIBLE THROUGH FRIDAY...WIDESPREAD RAIN IS
NOT EXPECTED TO FALL UNTIL FRIDAY NIGHT AND SATURDAY WITH THE
ARRIVAL OF A STRONG COLD FRONT.
&&
.NEAR TERM /THROUGH FRIDAY/...
STARTING TO LOOK AS IF PRECIPITATION WILL JUST NOT GET STARTED THIS
AFTERNOON. SHOWERS HAVE MANAGED TO STAY ACROSS CENTRAL OHIO AND
WESTERN WEST VIRGINIA...NOT ENTERING OUR FORECAST AREA. RAP MODEL
SHOWS A VERY SMALL SHORTWAVE OVER OHIO DISSIPATING AS IT MOVES TO
THE SOUTHEAST THIS AFTERNOON...AND EXCEPT FOR THE FAR WESTERN OHIO
COUNTIES...CONDITIONS SHOULD REMAIN DRY WELL PAST MIDNIGHT. COULD
START TO SEE SOME CONVECTION OVERNIGHT...BUT REALLY THINK THAT
DIURNAL TIMING SHOULD STILL PUSH MOST PRECIPITATION UNTIL FRIDAY
AFTERNOON. HIGH-RESOLUTION MODELS ARE SHOWING VERY LITTLE
PRECIPITATION AHEAD OF THE COLD FRONT EVEN DURING THE AFTERNOON. SPC
CONVECTIVE OUTLOOK SHOWS A POSSIBILITY FOR A STRONG TO SEVERE STORM
FRIDAY...BUT BOTH INSTABILITY AND WIND SHEAR SHOULD REMAIN MARGINAL.
EVEN WITHOUT PRECIPITATION...THINK THAT MOIST LOW LEVELS COULD ALLOW
FOR ANOTHER ROUND OF LOW CLOUDS TO DEVELOP AFTER MIDNIGHT AND
PERSIST INTO THE MORNING HOURS. THIS WOULD SQUASH MUCH OF THE
DIURNAL TEMPERATURE CURVE...ALLOWING FOR ABOVE NORMAL LOW
TEMPERATURES...WITH HIGHS REACHING INTO THE UPPER 70S WITH MOSTLY
HIGH CLOUDS TOMORROW.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
MODEL SOLUTIONS CONTINUE TO GENERALLY VARY LESS THAN 6 HOURS WITH
THE TIMING OF THE FRONTAL PROGRESSION ACROSS THE AREA ON SATURDAY.
IN GENERAL...MODELS FAVOR A PASSAGE IN OHIO IN THE MORNING...AND
PENNSYLVANIA/WEST VIRGINIA IN THE AFTERNOON. THE FORECAST WAS
ADJUSTED A BIT TOWARD THE SLOWER END OF THE GUIDANCE OWING TO A
SECONDARY VORT MAXIMA DIGGING INTO THE BASE OF THE MID-LEVEL
TROUGH SUPPORTING THE FRONTAL PROGRESSION. WITH THIS TYPE OF
DEVELOPMENT...A SLOWER SOLUTION GENERALLY VERIFIES.
ADDITIONALLY...THE 12Z GFS/ECMWF/CANADIAN ALL CAME IN A TAD SLOWER
THAN THE NAM AND THEIR PREVIOUS CYCLE COUNTERPARTS...SO HANGING
ONTO HIGHER POPS INTO THE AFTERNOON STILL SEEMS PRUDENT.
CONVECTIVE DEVELOPMENT ALONG THE FRONT STILL SEEMS RATHER
UNLIKELY. UPPER JET STREAK COUPLING...WHILE STRONG OVER INDIANA
FRIDAY EVENING AND NIGHT...QUICK BECOMES LESS IMPRESSIVE ON
SATURDAY AS THE SECONDARY VORT DIGS INTO THE TROUGH. AS THIS
OCCURS...THE NORTHER JET STREAK QUICKLY BECOMES DISASSOCIATED FROM
THE SOUTHERN JET STREAK BY SATURDAY AFTERNOON. AS A
CONSEQUENCE...UPPER FORCING FADES A BIT AS THE FRONT PROGRESSES
ACROSS THE AREA. ADDITIONALLY...SIGNIFICANT ADVANCE CLOUD COVER
SHOULD PRECLUDE SIGNIFICANT INSTABILITY GENERATION.
FURTHERMORE...WITH THE DISSOCIATION OF THE LARGE SCALE FLOW IN THE
MID AND UPPER LEVELS...SHEAR VALUES ACTUALLY DECREASE IN OUR
SECTOR OF THE FRONT THROUGH THE DAY SATURDAY. AS SUCH...WITH
LITTLE INSTABILITY AND WEAKENING SHEAR...THUNDERSTORM CHANCES DO
NOT SEEM LIKELY WITH FADING UPPER LEVEL SUPPORT. HOWEVER...WHILE
NOT LIKELY...LOW LEVEL CONVERGENCE ALONG THE FRONT AND SOME AMOUNT
OF FRONTOGENETICAL FORCING MAY GIVE ENOUGH OF A KICK TO WORK WITH
THE ROUGHLY 300 J/KG OF 1000-700 MB MUCAPE IMMEDIATELY ALONG THE
FRONT. TO COVER THIS...SLIGHT CHANCES OF THUNDER WERE CARRIED
BASICALLY RIGHT WITH THE FRONTAL PASSAGE.
WHILE THUNDER DOES NOT SEEM PARTICULARLY LIKELY...MODEL TIME HEIGHT
SECTIONS DO INDICATE NEGATIVE THETA-E LAPSE RATES THROUGH THE
DEEPLY SATURATED LAYER IN THE 5-10 KFT LAYER...WHICH IS ALL WARMER
THAN 0C. SHALLOW CONVECTION WITH LOW CENTROID ECHOES AND DECENT
INSTABILITY IN THE STRONGLY SATURATED LAYER COUPLED WITH PWATS UP
TOWARD 1.7 INCHES SHOULD ALLOW FOR A PERIOD OF FAIRLY HEAVY
RAINFALL ALONG THE FRONT. AS SUCH...QPF VALUES COULD PUSH AN INCH
ACROSS THE AREA DUE TO A BIT SLOWER FRONTAL PROGRESSION.
THE FRONT EXITS TO THE EAST SATURDAY NIGHT. MUCH COLDER AIR FLOODS
INTO THE REGION AS CONSENSUS 850 MB TEMPERATURES FALL TOWARD +2 TO
+4C. SOME STRATOCUMULUS GENERATION IS LIKELY OFF LAKE ERIE IN
NORTHWESTERLY FLOW THROUGH SUNDAY...WHICH SHOULD HOLD TEMPERATURES
BACK QUITE A BIT BELOW NORMAL. FRIES
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
STRONG SHORTWAVE TROUGH WILL CROSS THE AREA LATE SAT/SAT NIGHT
WITH THE CAA. COULD SEE SOME ADDITIONAL SHOWERS DEVELOP WITH THIS
FEATURE.
STRONG SURFACE HIGH WILL MOVE THROUGH THE GREAT LAKES FOR THE
REMAINDER OF THE LONG TERM.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
CLOUDS HAVE BEEN SLOW TO LIFT TODAY...BUT THINK THAT ALL LOCATIONS
SHOULD EVENTUALLY REACH VFR BY SUNSET. MODELS ARE INDICATING THAT
WITH MOIST LOW LEVELS...ANOTHER ROUND OF LOW MVFR/IFR CIGS ARE
POSSIBLE OVERNIGHT INTO FRIDAY MORNING. CONSIDERING MODEL GUIDANCE
PICKED UP ON THIS LAST NIGHT...WILL TRUST THE GUIDANCE A BIT MORE
WITH THE LOW CIG FORECAST TONIGHT. WITH WINDS A BIT STRONGER FRIDAY
MORNING COMPARED TO THIS MORNING...THINK CLOUDS WILL SCATTER OUT BY
MID MORNING...WITH GENERALLY HIGH CLOUDS AHEAD OF THE ADVANCING COLD
FRONT. WIDESPREAD PRECIPITATION IS EXPECTED TO STAY WEST OF ZZV BY
18Z AND PIT BY 00Z SATURDAY.
.OUTLOOK.../FRIDAY NIGHT THROUGH TUESDAY/...
WIDESPREAD RESTRICTIONS CAN BE EXPECTED FRI NGT THROUGH SAT NGT AS
RAIN DVLPS WITH A CROSSING CDFNT. HIGH PRESSURE SHOULD THEN KEEP
CONDITIONS VFR SUNDAY THROUGH TUESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GAYLORD MI
409 PM EDT THU SEP 19 2013
.SYNOPSIS...
ISSUED AT 407 PM EDT THU SEP 19 2013
IT WILL BE WARM AND HUMID ACROSS NORTHERN MICHIGAN THROUGH
FRIDAY...AHEAD OF A STRONG COLD FRONT PUSHING ACROSS THE WESTERN
LAKES. THIS BOUNDARY WILL GENERATE SEVERAL ROUNDS OF SHOWERS AND
THUNDERSTORMS THROUGH FRIDAY...BEFORE SEASONAL CONDITIONS AND SOME
LAKE INDUCED RAINS RETURN TO NORTHERN MICHIGAN TO START THE WEEKEND.
HIGH PRESSURE WILL SETTLE INTO THE REGION SUNDAY AND MONDAY. THIS
PATTERN WILL GENERATE AN EXTENDED STRETCH OF DRY AND COMFORTABLE
WEATHER ACROSS THE GREAT LAKES FOR THE FIRST OFFICIAL WEEK OF FALL.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 407 PM EDT THU SEP 19 2013
WARM...AND AN APPRECIABLY MUGGY AIRMASS...HAS OVERSPREAD THE NORTH
WOODS THIS AFTERNOON. DESPITE THIS...LOSS OF ANY DYNAMICS HAS LED
TO A DRY LATE MORNING AND EARLY AFTERNOON...WITH FOCUS FOR RAINS
SHIFTING WELL TO OUR SOUTH AND WEST. FORMER TIED TO REMNANT COLD
POOL AND LOW LEVEL JET DYNAMICS...WITH THE LATTER FOCUSED ALONG AND
AHEAD OF STRONG SHORTWAVE TROUGH AND ATTENDANT COLD FRONT SUPPORT.
THIS UPSTREAM SYSTEM WILL BE THE IMPETUS FOR ADDITIONAL SHOWERS AND
STORMS HEADING INTO TONIGHT AND FRIDAY. FORECAST CHALLENGES CENTER
ON THESE RAIN POSSIBILITIES.
TOUGH CALL FOR THE REMAINDER OF THIS AFTERNOON INTO EARLY THIS
EVENING. APPEARS FOCUS FOR ANY RAINS WILL BE CENTERED ON LOW LEVEL
CONVERGENCE AXES AND DEVELOPMENT OF SURFACE INSTABILITY. NOTED
CONVERGENCE AXIS DRIFTING SLOWLY NORTH ACROSS THE HIGHLANDS AS OF
THIS WRITING...WELL EVIDENT ON LOCAL RADAR IMAGERY. PER SPS SURFACE
ANALYSIS...BULLSEYE OF 1.5K TO 2.0K ML CAPE HAS DEVELOPED OVER
INTERIOR NORTHERN LOWER MICHIGAN. STILL EVIDENCE OF SOME WEAKISH
CINH TO OVERCOME. REALLY NOT SURE HOW THIS WILL ALL PLAY OUT...BUT
FEEL ABOVE DEFINITELY WORTHY OF KEEPING SOME SHOWER AND STORM
MENTION HEADING INTO EARLY THIS EVENING. FOR WHAT IT`S
WORTH...LATEST RAP SHOWS GOOD STORM DEVELOPMENT HEADING INTO THIS
PERIOD...FOCUSED ACROSS THE INTERIOR HIGHLANDS. RELATIVELY HIGH
PWATS SUPPORT LOCALLY HEAVY RAINS IF/WHERE CONVECTION DEVELOPS.
FOCUS WILL SHIFT TO LOW LEVEL JET DYNAMICS AND APPROACH OF COLD
FRONT FOR SHOWER AND STORM POTENTIAL HEADING INTO TONIGHT. RECENT
TRENDS AND PATTERN RECOGNITION SUPPORT BEST FORCED LOW LEVEL MASS
CONVERGENCE FOCUSED ALONG THE LAKE MICHIGAN CORRIDOR OF NORTHWEST
LOWER AND EASTERN UPPER MICHIGAN AFTER 05Z. MOISTURE REMAINS
GREAT...AND SIMPLE MAGNITUDE OF CONVERGENCE SHOULD BE ENOUGH TO
DRIVE ADDITIONAL ACTIVITY. WILL FOCUS BEST POTENTIAL IN THESE
AREAS...TAPERING TO JUST CHANCY WORDING ACROSS NORTHEAST LOWER
MICHIGAN. ELEVATED NATURE OF STORMS SHOULD PRECLUDE MUCH SEVERE
POTENTIAL. ONCE AGAIN... HOWEVER...GOOD MOISTURE PROFILES SUPPORT
LOCALLY HEAVY RAIN CONCERNS.
SURFACE FRONT LOOKS TO REMAIN AGGRESSIVE HEADING INTO FRIDAY...WITH
LATEST GFS/ECMWF TRENDS DRIVING THE FRONT INTO LAKE HURON THROUGH
EARLY AFTERNOON. PRE-FRONTAL SHOWERS AND STORMS SHOULD
CONTINUE...WITH STRONG UPPER JET SUPPORT AND FGEN DYNAMICS DRIVING
POST-FRONTAL RAINS IMMEDIATELY BEHIND THE SURFACE PORTION OF THE
FRONT. INHERITED GRIDS WELL TRENDED THIS DIRECTION WITH NO
SIGNIFICANT CHANGES NEEDED. DESPITE DECENT KINEMATICS...PLENTY OF
CLOUD COVER AND FASTER TIMING OF FRONT LOOKS TO KEEP SURFACE BASED
INSTABILITY IN CHECK...ONCE AGAIN PRECLUDING MUCH SEVERE WEATHER
POTENTIAL. LATEST SPC GRAPHICS CONCUR...KEEPING SLIGHT CHANCE
WORDING JUST TO OUR SOUTHEAST.
&&
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 407 PM EDT THU SEP 19 2013
OVERVIEW AND TRENDS: SUBSTANTIAL LONG WAVE TROUGHING IN PLACE THIS
MORNING FROM THE GULF OF ALASKA DOWN ALONG THE WEST COAST...WITH
DOWNSTREAM RIDGING/WARM AIR ACROSS THE CENTRAL CONUS INTO THE GREAT
LAKES...AND TROUGHING FROM GREENLAND DOWN THROUGH EASTERN CANADA.
LONG WAVE RIDGING IS STILL SLATED TO SLOWLY ADVANCE INTO THE EASTERN
CONUS THROUGH THE WEEKEND...WHILE LARGER SCALE FLOW FLATTENS AND
CONTRACTS TOWARD THE POLE AS WE GO THROUGH NEXT WEEK. SO...NO LONG
LASTING TRANSITION TOWARD COOL FALL WEATHER JUST YET.
ON THE SMALLER SCALE...A COUPLE OF STRONGER SHORT WAVES EMBEDDED
WITHIN THE LARGER SCALE FLOW...ONE PUSHING INTO THE NRN PLAINS THAT
WILL IMPACT US OVER THE NEXT FEW DAYS...AND ANOTHER STRONG WAVE JUST
OFF THE PACIFIC NW COAST THAT WILL PUSH INTO THE PAC NW LATER THIS
WEEKEND. CLOSER TO HOME...LOW PRESSURE STRETCHES FROM SOUTH-CENTRAL
CANADA INTO THE NRN PLAINS...AHEAD OF THE AFOREMENTIONED SHORT WAVE.
ASSOCIATED WARM FRONT STRETCHES DOWN THROUGH THE MIDWEST AND
TRAILING COLD FRONT FROM MINNESOTA INTO THE CENTRAL PLAINS. HAVE
DEALT WITH A COUPLE OF ROUNDS OF SHOWERS AND STORMS WORKING THROUGH
THE REGION ALONG ADVANCING LOW LEVEL MOISTURE AXIS PUSHING INTO THE
REGION NORTH OF THE WARM FRONT.
LATE FRIDAY AFTERNOON THROUGH SATURDAY...SHORT WAVE/THERMAL TROUGH
AXIS ADVANCES INTO THE GREAT LAKES OVERNIGHT THROUGH SATURDAY
MORNING. FROPA TIMING AMONG MODEL SOLUTIONS STILL IN GOOD
AGREEMENT...KICKING THE FRONT EASTWARD INTO LAKE HURON BY EARLY
FRIDAY EVENING. CONSENSUS AMONG MODEL QPF ALSO SUGGESTS MOST...IF
NOT ALL...SYNOPTIC PRECIP WILL END BY EARLY EVENING...SAVE FOR JUST
A SMALL SLIVER OF THE E/SE COUNTIES. HOWEVER...GIVEN THE STRONG S-N
ORIENTED UPPER JET CORE ALONG THE BASE OF THE INCOMING TROUGH THAT
SLIDES ACROSS THE CWA RIGHT BEHIND THE FRONT...AM STILL CONCERNED
THAT POST FRONTAL/JET FORCED RAINFALL LINGERS JUST A BIT LONGER INTO
THE EARLY TO MID EVENING HOURS THAN MODEL QPF SUGGESTS. WITH THAT IN
MIND...HAVE SLOWED PRECIP ENDING JUST A BIT LATE FRIDAY AFTERNOON
AND EARLY EVENING. PROBABLY THE PATH OF LEAST REGRET AT THIS POINT
GIVEN ALL THE FRIDAY EVENING ACTIVITIES. REGARDLESS...LOW LEVEL
COOL/MOIST AIR OVERSPREADING THE REGION FRIDAY EVENING (AND SOME
SEMBLANCE OF A WEAK LOW LEVEL TROUGH) MAY LEAD TO STRATUS AND
PERHAPS SOME PATCHY DRIZZLE FRIDAY EVENING. THEN...SUBSIDENCE AND
STRONG COLD ADVECTION CONTINUE THROUGH THE REST OF FRIDAY NIGHT AND
THROUGH THE DAY SATURDAY WITH H8 TEMPS DIPPING TO A FEW DEGREES
ABOVE 0C BY SATURDAY MORNING...AND DOWN AROUND 0C DURING THE DAY
SATURDAY. PLENTY ENOUGH COOL AIR/LAKE INSTABILITY AND SYNOPTIC
MOISTURE ALONG THE BACKSIDE OF THE DEPARTING LOW FOR LAKE
EFFECT/INDUCED RAIN SHOWERS OVERNIGHT FRIDAY NIGHT THROUGH A GOOD
PART OF SATURDAY. SO ANOTHER COOL-ISH SATURDAY LOOKS ON TAP WITH
MAINLY CLOUDY SKIES...SCATTERED RAIN SHOWERS AND SOME GUSTIER NW
WINDS.
SATURDAY NIGHT THROUGH SUNDAY NIGHT...IMPROVEMENT SATURDAY NIGHT AND
ESPECIALLY SUNDAY AS LARGE EXPANSE OF HIGH PRESSURE BUILDS OVER THE
REGION AND SUBSTANTIALLY DRIER AIR BUILDS OVERHEAD. COOLEST NIGHTS
OF FORECAST WILL OCCUR BOTH SATURDAY NIGHT AND SUNDAY NIGHT AS
CLEARING SKIES/WEAKENING WINDS SET THE STAGE FOR GOOD RADIATIONAL
COOLING. A GOOD DEAL OF SUNSHINE FOR SUNDAY WITH TEMPERATURES
REBOUNDING JUST A BIT TO THE MIDDLE 50S TO LOWER 60S.
MONDAY THROUGH THURSDAY...LARGE EXPANSE OF HIGH PRESSURE WILL REMAIN
THE DOMINANT WEATHER FEATURE ACROSS THE GREAT LAKES AND ACROSS
EASTERN CANADA THROUGH MUCH OF NEXT WEEK...WITH FAIR WEATHER
ANTICIPATED TO KICK OFF THE FIRST OFFICIAL WEEK OF FALL. GRADUAL
WARMING TREND THROUGH MIDWEEK AS TEMPERATURES REBOUND BACK TO AROUND
NORMAL READINGS FOR MID-LATE SEPTEMBER. GFS SOLUTION HAS ENOUGH
WARM/MOIST ADVECTION INTO THE UPPER MIDWEST/WESTERN GREAT LAKES TO
CONSIDER SOME CHANCES FOR SHOWERS BY THURSDAY. ECMWF IS NOWHERE
CLOSE WITH HIGH PRESSURE REMAINING DOMINANT. WILL FOLLOW THE DRY
ECMWF FOR NOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 135 PM EDT THU SEP 19 2013
SHOWERS AND STORMS WILL LIKELY BE ON THE INCREASE ONCE AGAIN
HEADING THROUGH TONIGHT AND INTO FRIDAY AS A STRONG COLD FRONT
MOVES THROUGH THE REGION. WILL INTRODUCE MVFR CONDITIONS WITH
PASSAGE OF BETTER SHOWERS AND MOST AGGRESSIVE DYNAMICS. SOME
CONCERN FOR IFR CIGS DEVELOPING IN AND JUST BEHIND THE PRIMARY
RAIN SHIELD HEADING INTO FRIDAY MORNING. CONFIDENCE JUST NOT THERE
TO INCLUDE AT THIS TIME. LOW LEVEL JET WILL LEAD TO WIND SHEAR
OVER THE WESTERN TAF SITES TONIGHT.
&&
.MARINE...
ISSUED AT 407 PM EDT THU SEP 19 2013
GUSTY SOUTH WINDS WILL CONTINUE TONIGHT...ESPECIALLY ACROSS
LAKE MICHIGAN...AS A STRONG COLD FRONT APPROACHES THE NORTHERN
LAKES. CURRENT TRENDS SUPPORT CONDITIONS REMAINING JUST BELOW SCA
CRITERIA. SHOWERS AND STORMS EXPECTED TO REDEVELOP THIS EVENING AND
OVERNIGHT...POSSIBLY LEADING TO LOCAL ENHANCEMENT OF WINDS. WINDS
VEER MORE WESTERLY BEHIND THE PASSING FRONT FRIDAY...REMAINING GUSTY
AT TIMES. WINDS INCREASE AND BECOME NORTHWEST FRIDAY NIGHT AND
SATURDAY. SCA/S WILL LIKELY BE NEEDED DURING THIS PERIOD.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
SYNOPSIS...KB
SHORT TERM...MB
LONG TERM...BA
AVIATION...MB
MARINE...MB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
355 PM CDT THU SEP 19 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 237 PM CDT THU SEP 19 2013
AS OF 2 PM...THE FRONT WAS STILL SLOWLY MOVING ACROSS THE EASTERN
HALF OF MINNESOTA...BUT IT HAD NOT PASSED THROUGH THE TWIN CITIES
METRO. EVEN WITH THE THE THUNDERSTORM ACTIVITY DIMINISHING IN
WESTERN WI...THERE IS STILL A NICE POOL OF INSTABILITY IN WI AND
EASTERN IA. THE STEEPEST CAPE GRADIENT EXTENDS FROM ROUGHLY EAU
CLAIRE...TO ALBERT LEA. THIS SAME AREA HAS SEEN MOSTLY CLEAR SKIES
SO FAR TODAY...BUT TOWERING CU HAS FILLED IN ACROSS MUCH OF THIS
AREA WITH SCATTERED SHOWERS. IF THERE IS TO BE CONVECTIVE REDEVELOP
IN THE MPX FORECAST AREA...THEN THIS IS THE SPOT TO KEEP AN EYE ON.
THERE IS A NICE SHORTWAVE IN EASTERN NE THAT SHOULD CONTINUE TO
DRIVE STORMS ACROSS IA. FARTHER NORTH THERE ARE FAR MORE QUESTIONS
AND WE THINK ACTIVITY WILL LARGELY REMAIN EAST AND SOUTH OF HERE.
THAT BEING SAID...THE 19.17Z HRRR HAS ANOTHER LINE OF STORMS GOING
RIGHT ALONG THE AFOREMENTIONED CAPE GRADIENT LATE THIS
AFTERNOON...AROUND 21Z FOR EAU CLAIRE.
OTHERWISE...LOOK FOR SOME NICE COLD ADVECTION TONIGHT AND TOMORROW
WITH A DRIER AND BREEZY NORTHWEST FLOW. THERE IS ACTUALLY A
SECONDARY COLD FRONT BACK ACROSS THE DAKOTAS ASSOCIATED WITH THAT
STRATO CU DECK AND TEMPS IN THE UPPER 40S AND LOWER 50S. THAT IS ON
TAP FOR TOMORROW. THE AIR WILL MODIFY...BUT WOULD NOT BE SURPRISED
IF SOME SITES IN CENTRAL MN STRUGGLE TO GET OUT OF THE 50S. WE
LOWERED HIGHS TOMORROW A BIT...BUT PROBABLY COULD HAVE GONE A COUPLE
DEGREES MORE. IT WILL BE A VERY FALL LIKE DAY TOMORROW.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 355 PM CDT THU SEP 19 2013
LOTS OF DISCREPANCIES EXIST IN THE LONG RANGE WITH RESPECT TO
TIMING OF INDIVIDUAL WAVES...BUT MODELS DO AGREE ON THE GENERAL
PROGRESSION OF THE LARGE SCALE UPPER AIR PATTERN. THE WEEKEND WILL
START WITH A RIDGE MOVING ACROSS THE NATIONS MID SECTION...BUT BY
MONDAY...AN ANOMALOUSLY STRONG UPPER RIDGE WILL BECOME CENTERED
OVER THE THE SE CONUS...WITH A DEEP TROUGH CARVING OUT ACROSS WRN
NOAM. DURING THE WEEK...THIS WRN TROUGH WILL SLOWLY DRIFT TOWARD
THE CENTRAL CONUS...APPROACHING THE UPPER MS VALLEY TOWARD THE END
OF NEXT WEEK.
SATURDAY STILL LOOKS TO START OUT IN THE UPPER 30S TO MID
40S...BUT DID NUDGE LOWS A COUPLE OF DEGREES UP...AS THE RIDGE
AXIS DOES NOT LOOK TO COME INTO WRN MN UNTIL CLOSER TO DAY
BREAK...KEEPING WINDS UP ENOUGH TO KEEP THE ATMO FROM COMPLETELY
DECOUPLING. OTHERWISE...ONLY THING REMOTELY SIGNIFICANT ABOUT THE
WEATHER THIS WEEKEND WILL BE THE BREEZY CONDITIONS DEVELOPING
SUNDAY AS GRADIENT TIGHTENS SIGNIFICANTLY ACROSS MN IN RESPONSE TO
A 1020 MB HIGH OVER THE GREAT LAKES AND A 995 MB LOW OVER THE WRN
DAKOTAS. 1000-850 WINDS OFF THE NAM INCREASE TO OVER 30 KTS BY THE
AFTERNOON IN WRN MN...SO SHOULD TURN INTO A FAIRLY BREEZY DAY IN
OUR TYPICALLY WINDY AREAS.
TIMING DETAILS QUICKLY SHOW UP WITH THE WAVE DUE TO MOVE THROUGH ON
MONDAY AS MODELS STRUGGLE TO PIN DOWN HOW THE RIDGING OVER THE
SOUTHEAST WILL IMPACT THE SPEED OF WAVES BACK THIS DIRECTION. THE
GEM/GFS CONTINUE TO BRING A POTENT NEGATIVELY TILTED THROUGH
ACROSS THE NRN PLAINS MONDAY...WITH A BAND OF SHRA/TSRA COMING
ALONG WITH AS WELL. THE 19.12 ECMWF SLOWED DOWN CONSIDERABLY WITH
THIS FEATURE...BRINGING IT THROUGH ABOUT 12 HRS LATER...WITH
PRECIP COMING THROUGH MONDAY NIGHT AS A RESULT. GIVEN TIMING
DIFFERENCES...CONTINUED WITH CHANCES POPS MON/MON NIGHT...BUT AT
SOME POINT...GIVEN THE DYNAMICS ASSOCIATED WITH THE NEGATIVELY
TITLED WAVE...WE SHOULD BE HEADING FOR A HIGH POP/LOW QPF TYPE
SCENARIO ONCE BETTER TIMING CAN BE NAILED DOWN. GIVEN THE RIDGING
TO THE SE...ITS USUALLY A SAFER BET TO GO THE SLOWER ROUTE.
THIS RIDGE TO THE SOUTHEAST WILL BE A MAJOR PLAYER FOR THE WEATHER
HERE THROUGH THE REST OF THE WEEK...AS IT WILL ACT TO DEFLECT
MUCH OF THE SHORTWAVE ENERGY TO THE NW OF THE MPX AREA. HAVE SEEN
MODELS RESPOND TO THIS...WITH EACH RUN GRADUALLY SLOWING DOWN WHEN
THE NEXT SYSTEM WILL IMPACT THE AREA. THE GFS WANTS TO BRING A
POTENT FRONT/LOW THROUGH WED NIGHT/THU...WHILE THE ECMWF HOLDS OFF
UNTIL FRIDAY. MUCH LIKE WAS STATED IN THE PREVIOUS
PARAGRAPH...GIVEN THE STRENGTH OF THE RIDGING TO THE SE...THE
SLOWER PROGRESSION WILL LIKELY BE THE WAY THINGS GO...BUT GIVEN
THE BLENDING PROCEDURE USED...PRECIP CHANCES RETURN WEDNESDAY.
THOUGH THERE IS UNCERTAINTY ABOUT PRECIP...WHAT IS MORE CERTAIN IS
THAT SW FLOW RESULTING FROM THE TROUGH WEST/RIDGE EAST WILL BRING
WITH IT TEMPERATURES WELL ABOVE NORMAL...WITH HIGHS IN THE 80S
LOOKING POSSIBLE BY THE MIDDLE OF NEXT WEEK...WHICH THANKS TO OUR
RAPIDLY FALLING AVERAGE HIGHS WOULD BE CLOSE 20 DEGREES ABOVE
NORMAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1240 PM CDT THU SEP 19 2013
IMMEDIATE CONCERN THIS AFTERNOON ACROSS THE AREA IS THE DEPARTING
THUNDER...BRIEF POST FRONTAL LOW CIGS...AND RAPIDLY
VARYING/CHANGING WIND DIRECTION. ALL MN TAF SITES ARE DONE WITH
THE THUNDER AT THIS POINT...BUT WESTERN WI WILL SEE ADDITIONAL
THUNDER FOR THE NEXT HOUR OR TWO. A NARROW AREA OF IFR CIGS BEHIND
THE FRONT HAS DEVELOPED AND WILL TRANSLATE EAST AS IT SLOWLY
DISSIPATES THIS AFTERNOON. THIS WILL NEED TO BE MONITORED TO SEE
HOW LONG IT HOLDS TOGETHER. WINDS TURN NW BY THIS EVE ACROSS THE
ENTIRE AREA...AND VFR CONDITIONS ARE EXPECTED BEHIND THE POST
FRONTAL STRATUS...UNTIL THE EARLY MORNING HOURS. AT THAT TIME...A
SHIELD OF LOW STRATUS WILL ADVECT IN FROM THE NORTHWEST...WITH THE
ENTIRE AREA SEEING MVFR CIGS...WITH THE POSSIBILITY OF IFR
CEILINGS BEFORE SUNRISE. CIGS WILL LIFT TO VFR BY LATE
MORNING/EARLY AFTERNOON. WINDS TOMORROW WILL BE GUSTY FROM THE NORTHWEST.
KMSP...VFR CONDITIONS SHOULD PREVAIL UNTIL THE OVERNIGHT HOURS
WHEN THE LOW STRATUS APPROACHES NEAR SUNRISE. ADVERTISING MVFR
CIGS 10-16Z...BUT BEWARE OF THE POTENTIAL FOR CEILINGS CLOSER TO
1K FT FROM AROUND 10-13Z. WINDS WILL BE NW BY TONIGHT AND REMAIN
THAT WAY THROUGH THE TAF PERIOD. MVFR CIGS LIFT DUE TO MIXING TO
VFR BY LATE MORNING.
/OUTLOOK FOR KMSP/
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...CLF
LONG TERM...MPG
AVIATION...SPD
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
238 PM CDT THU SEP 19 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 237 PM CDT THU SEP 19 2013
AS OF 2 PM...THE FRONT WAS STILL SLOWLY MOVING ACROSS THE EASTERN
HALF OF MINNESOTA...BUT IT HAD NOT PASSED THROUGH THE TWIN CITIES
METRO. EVEN WITH THE THE THUNDERSTORM ACTIVITY DIMINISHING IN
WESTERN WI...THERE IS STILL A NICE POOL OF INSTABILITY IN WI AND
EASTERN IA. THE STEEPEST CAPE GRADIENT EXTENDS FROM ROUGHLY EAU
CLAIRE...TO ALBERT LEA. THIS SAME AREA HAS SEEN MOSTLY CLEAR SKIES
SO FAR TODAY...BUT TOWERING CU HAS FILLED IN ACROSS MUCH OF THIS
AREA WITH SCATTERED SHOWERS. IF THERE IS TO BE CONVECTIVE REDEVELOP
IN THE MPX FORECAST AREA...THEN THIS IS THE SPOT TO KEEP AN EYE ON.
THERE IS A NICE SHORTWAVE IN EASTERN NE THAT SHOULD CONTINUE TO
DRIVE STORMS ACROSS IA. FARTHER NORTH THERE ARE FAR MORE QUESTIONS
AND WE THINK ACTIVITY WILL LARGELY REMAIN EAST AND SOUTH OF HERE.
THAT BEING SAID...THE 19.17Z HRRR HAS ANOTHER LINE OF STORMS GOING
RIGHT ALONG THE AFOREMENTIONED CAPE GRADIENT LATE THIS
AFTERNOON...AROUND 21Z FOR EAU CLAIRE.
OTHERWISE...LOOK FOR SOME NICE COLD ADVECTION TONIGHT AND TOMORROW
WITH A DRIER AND BREEZY NORTHWEST FLOW. THERE IS ACTUALLY A
SECONDARY COLD FRONT BACK ACROSS THE DAKOTAS ASSOCIATED WITH THAT
STRATO CU DECK AND TEMPS IN THE UPPER 40S AND LOWER 50S. THAT IS ON
TAP FOR TOMORROW. THE AIR WILL MODIFY...BUT WOULD NOT BE SURPRISED
IF SOME SITES IN CENTRAL MN STRUGGLE TO GET OUT OF THE 50S. WE
LOWERED HIGHS TOMORROW A BIT...BUT PROBABLY COULD HAVE GONE A COUPLE
DEGREES MORE. IT WILL BE A VERY FALL LIKE DAY TOMORROW.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 312 AM CDT THU SEP 19 2013
STRONG CAA IN THE WAKE OF THE COLD FRONT AND RESULTANT STEEP LOW
LEVEL LAPSE RATES WILL PROMOTE GUSTY WINDS AND A DEVELOPMENT OF
STRATOCU BEGINNING LATE TONIGHT TO THE NORTH AND WEST...PUSHING
OVERHEAD FRIDAY. MODEST AMOUNTS OF INSTABILITY THROUGH THE CLOUD-
BEARING LAYER MAY ALSO BRING A FEW SPRINKLES TO THE REGION...
PARTICULARLY NORTH OF THE MINNESOTA RIVER. LIGHT QPF ON THE
NAM/GFS/ECMWF ALSO HINT TOWARD THIS. THUS...INCREASED CLOUDS AND
WINDS...AND DECREASED TEMPERATURES FRIDAY FROM THE LAST FORECAST
PACKAGE.
THE HIGH WILL PUSH ACROSS WESTERN MINNESOTA FRIDAY NIGHT.
FORECAST SOUNDINGS REMAIN QUITE MIXED...BUT AM A BIT SKEPTICAL OF
THIS WITH THE SURFACE HIGH SO NEARBY. CLOUDS WILL QUICKLY
DISSIPATE FRIDAY EVENING AS CYCLONIC FLOW PUSHES OUT...SETTING THE
STAGE FOR A COLD NIGHT OVER THE AREA WITH LOWS IN THE MID 30S TO
LOWER 40S.
UPPER RIDGING QUICKLY BUILDS BACK OVER THE PLAINS DURING THE
WEEKEND. A FAIRLY IMPRESSIVE TEMPERATURE GRADIENT IS POSSIBLE ON
EITHER SIDE OF THE SURFACE RIDGE AXIS ACROSS THE CWA SATURDAY
AFTERNOON.
A SOUTHEASTERLY SURFACE FLOW WILL ENVELOP THE ENTIRE AREA FROM
SUNDAY INTO EARLY NEXT WEEK AS A SOUTHWEST FLOW IN THE UPPER
ATMOSPHERE STEERS WEAKENING SYSTEMS TO THE NORTH. ONE SUCH SYSTEM
WILL LIMP THROUGH MONDAY/MONDAY NIGHT. WITH RIDGING BUILDING IN
IMMEDIATELY IN THE WAKE OF THE SYSTEM...A DE-AMPLIFICATION OF SAID
SYSTEM WILL TAKE PLACE AND LITTLE OR NO FORCING WILL ACCOMPANY
WHAT IS LEFT OF THE FRONT. THUS...MAINTAINED ONLY LOW POPS.
WINDS WILL VEER MORE SOUTHERLY MIDWEEK WITH WARMER AND MORE HUMID
AIR RETURNING. MODELS ARE INCONSISTENT WITH THE POSITIONING OF A
SW-NW ORIENTED SURFACE BOUNDARY WITH THE EC FURTHER NORTH THAN
THE GFS. GFS SOLUTION WOULD BRING HIGHER POPS. EITHER
WAY...TEMPERATURES SHOULD BE 10-15 DEGREES ABOVE AVERAGE DURING
THIS PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1240 PM CDT THU SEP 19 2013
IMMEADITE CONCERN THIS AFTERNOOON ACROSS THE AREA IS THE DEPARTING
THUNDER...BRIEF POST FRONTAL LOW CIGS...AND RAPIDLY
VARYING/CHANGING WIND DIRECTION. ALL MN TAF SITES ARE DONE WITH
THE THUNDER AT THIS POINT...BUT WESTERN WI WILL SEE ADDITIONAL
THUNDER FOR THE NEXT HOUR OR TWO. A NARROW AREA OF IFR CIGS BEHIND
THE FRONT HAS DEVELOPED AND WILL TRANSLATE EAST AS IT SLOWLY
DISSIPATES THIS AFTERNOON. THIS WILL NEED TO BE MONITIORED TO SEE
HOW LONG IT HOLDS TOGETHER. WINDS TURN NW BY THIS EVE ACROSS THE
ENTIRE AREA...AND VFR CONDITIONS ARE EXPECTED BEHIND THE POST
FRONTAL STRATUS...UNTIL THE EARLY MORNING HOURS. AT THAT TIME...A
SHIELD OF LOW STRATUS WILL ADVECT IN FROM THE NORTHWEST...WITH THE
ENTIRE AREA SEEING MVFR CIGS...WITH THE POSSIBILITY OF IFR
CEILINGS BEFORE SUNRISE. CIGS WILL LIFT TO VFR BY LATE
MORNING/EARLY AFTERNOON. WINDS TOMORROW WILL BE GUSTY FROM THE NORTHWEST.
KMSP...VFR CONDITIONS SHOULD PREVAIL UNTIL THE OVERNIGHT HOURS
WHEN THE LOW STRATUS APPROACHES NEAR SUNRISE. ADVERTISING MVFR
CIGS 10-16Z...BUT BEWARE OF THE POTENTIAL FOR CEILINGS CLOSER TO
1K FT FROM AROUND 10-13Z. WINDS WILL BE NW BY TONIGHT AND REMAIN
THAT WAY THROUGH THE TAF PERIOD. MVFR CIGS LIFT DUE TO MIXING TO
VFR BY LATE MORNING.
/OUTLOOK FOR KMSP/
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...CLF
LONG TERM...BORGHOFF
AVIATION...SPD
AREA FORECAST DISCUSSION
NWS BILLINGS MT
238 PM MDT THU SEP 19 2013
.SHORT TERM...VALID FOR FRI AND SAT...
UPPER TROF CONTINUES TO SHIFT EAST AND WE ARE BEGINNING TO SEE
HEIGHT RISES INTO CENTRAL MT. SOME LIGHT SHOWERS REMAIN EAST OF
MILES CITY...ASSOCIATED WITH WEAK SHORTWAVE EMBEDDED IN THE NW
FLOW ALOFT...BUT THIS ACTIVITY IS WEAKENING AND WILL BE DONE
BEFORE 00Z.
ISSUES FOR TONIGHT INCLUDE FOG AND FROST POTENTIAL. PLENTY OF
CLOUD COVER CURRENTLY EXISTS IN OUR EAST BUT THIS WILL BE
DISSIPATING INTO THE EVENING. CURRENT DEWPTS ARE NOTEWORTHY...IN
THE UPPER 30S TO AROUND 40...AND WILL NOT SEE ANY SIGNIFICANT LOW
LEVEL DRYING IN OUR EAST BEFORE SUNSET. WITH THIS IN MIND...AND AS
SFC RIDGE BUILDS TO THE SOUTHEAST ALLOWING FOR THE NWLY GRADIENT
TO RELAX...BELIEVE SOME FOG OR STRATUS DEVELOPMENT IS POSSIBLE IN
OUR EAST. MIGHT LEAN TOWARD PATCHY VALLEY FOG HERE AS RAP SHOWS A
DECENT NW WIND AT 850MB THRU 12Z. WITHOUT ANY STRATUS BELIEVE SOME
AREAS IN OUR FAR EAST WILL SEE SOME FROST WITH TEMPS INTO THE MID
30S TONIGHT. IN OUR WEST...CLEAR SKIES A CERTAINTY WITH ONLY WEAK
DOWNSLOPE GRADIENTS DEVELOPING AFTER MIDNIGHT. SO BELIEVE
NOTORIOUSLY COLDER SPOTS SUCH AS HARLOWTON...LIVINGSTON AND
SHERIDAN WILL SEE SOME FROST TONIGHT. DEWPTS ARE PROBABLY TOO HIGH
TO SUPPORT A REAL FREEZE THOUGH. GENERALLY SPEAKING HAVE LOWERED
TEMPS FOR TONIGHT A BIT MORE...AND THIS IS CONSISTENT WITH THE
SLOWER PROGRESSING UPPER TROF AND COOLING TREND IN ALL GUIDANCE.
FOR BILLINGS...COULD SEE MID OR UPPER 30S FOR LOWS ALONG THE
YELLOWSTONE VALLEY...BUT RIDGES SHOULD NOT FALL BELOW THE LOW 40S.
DRY WX WITH A WARMING TREND IN STORE FOR FRI/SAT AS STRONG RIDGE
ALOFT BUILDS OVER THE REGION. EXPECT TEMPS TO CLIMB BACK INTO THE
70S TOMORROW AND 80S ON SAT...WITH GOOD CONFIDENCE IN A STRONG
WARM UP SUPPORTED BY DRY AIRMASS SETTLING IN AND WHAT WILL BE DEW
PTS IN THE 20S AND 30S. DEEPER MIXING OF INCREASED SW WINDS ALOFT
WILL RESULT IN GUSTY WINDS FOR OUR WESTERN FOOTHILLS INCLUDING
LIVINGSTON ON SAT...WHICH WILL COINCIDE WITH AFTN RHS IN THE LOW
TEENS. THESE CONDITIONS WILL BE HIGHLIGHTED IN THE FIRE WEATHER
FORECAST.
NEXT PACIFIC TROF...THOUGH WEAKENING AS IT COMES INLAND...WILL
BEGIN TO IMPACT OUR FAR WEST LATE SAT NIGHT. HAVE SCALED BACK POPS
SLIGHTLY AND PUSHED THEM WEST AFTER 06Z...BASED ON MODEL CONSENSUS
FOR THIS SLOWER TIMING. WEAK COLD FRONT WILL ALLOW FOR COOLER
PACIFIC AIR TO BEGIN SPREADING IN FROM THE WEST LATE SAT NITE...
SETTING UP A COOLER SUNDAY.
JKL
.LONG TERM...VALID FOR SUN...MON...TUE...WED...THU...
THE EXTENDED FORECAST LOOKS A LOT MORE LIKE FALL WITH TWO WEATHER
SYSTEMS TO WATCH. THE FIRST SYSTEM WILL IMPACT THE REGION ON
SUNDAY...AND WILL BRING SOME SNOW SHOWERS TO HIGH ELEVATIONS IN
THE MOUNTAINS AND RAIN SHOWERS ACROSS THE REST OF THE FORECAST
AREA...BRINGING TEMPERATURES BACK TO NEAR SEASONAL NORMALS. THE
SECOND SYSTEM...WHICH IS MUCH MORE INTERESTING...WILL IMPACT THE
REGION BY WEDNESDAY AND THURSDAY...AND WILL BRING MUCH BELOW
NORMAL TEMPERATURES AND A GOOD CHANCE OF WIDESPREAD PRECIPITATION.
...SUNDAY THROUGH TUESDAY...
A SPLITTING TROUGH WILL CROSS THE REGION ON SUNDAY...BRINGING AN
INCREASE IN PACIFIC MOISTURE AND QG FORCING ACROSS THE FORECAST
AREA. ELEVATED MOUNTAIN LOCATIONS WILL LIKELY CATCH SOME SNOW
SHOWERS WITH THIS SYSTEM AS H7 TEMPS DECREASE TO AROUND 0C. WINDS
WILL REMAIN MOSTLY WESTERLY AND DOWNSLOPE...WHICH WILL ACT TO
LIMITE THE AMOUNT OF PRECIPITATON ACROSS THE PLAINS LOCATIONS.
HOWEVER...FULLY EXPECT A COOLER AND CLOUDY DAY WITH SCATTERED RAIN
SHOWERS ACROSS THE PLAINS. THE FLOW BEHIND THE WAVE FOR MONDAY AND
TUESDAY WILL REMAIN NEAR ZONAL WITH THE JET OVERHEAD...KEEPING
TEMPERATURES NEAR NORMAL AND A CHANCE OF SOME SHOWERS IN THE
MOUNTAINS...OTHERWISE THE REMAINDER OF THE FORECAST AREA SHOULD
STAY DRY.
...WEDNESDAY AND THURSDAY...
GLOBAL MODELS ARE EXTREMELY CONSISTENT WITH THE WEATHER PATTERN
OVER THE PACIFIC BY THIS TIME FRAME...AND ALL DEVELOP A DIGGING
TROUGH DOWN THE WEST COAST BY TUESDAY INTO WEDNESDAY. THE PATTERN
WILL OPEN THE DOOR TO MUCH COOLER TEMPERATURES FOR WEDNESDAY AND
THURSDAY. WHILE THERE ARE MINOR DIFFERENCES IN THE EVOLUTION OF
THE TROUGH...BOTH THE GFS AND ECMWF POSITION THE LOW JUST TO OUR
WEST BY WEDNESDAY AFTERNOON AND SLIDE THE LOW ACROSS OUR SOUTH BY
THURSDAY. THIS SOLUTION IS FAVORABLE FOR A PROLONGED UPSLOPE
EVENT. THAT COMBINED WITH THE DYNAMICS OF THE LOW COULD PRODUCE A
WIDESPREAD PRECIPITATION EVENT ACROSS THE AREA...AND IN PARTICULAR
ALONG THE FOOTHILLS AND EAST FACING MOUNTAIN LOCATIONS.
TEMPERATURES ARE COOL ENOUGH THAT SNOW IN THE MOUNTAINS WOULD BE
LIKELY AND COULD GET INTO HIGH FOOTHILLS LOCATIONS. TEMPERATURES
ACROSS THE PLAINS WOULD CERTAINLY BE THE COOLEST WE HAVE SEEN THIS
FALL...BUT AT THIS POINT LOOK JUST WARM ENOUGH FOR MAINLY RAIN
EVENT. THIS WEATHER SYSTEM WILL BE THE ONE TO WATCH AS IT BECOMES
CLOSER IN TIME.
CHURCH
&&
.AVIATION...
THE LOWER CLOUD DECK WILL CONTINUE TO ERODE FROM WEST TO EAST
ACROSS THE AREA AS DRIER AIR WORKS IN FROM THE WEST. MVFR CEILINGS
SHOULD BE LIMITED TO FAR EASTERN MONTANA...NEAR KBHK THIS
AFTERNOON. OTHERWISE VFR CONDITIONS WILL PREVAIL ACROSS ALL TAF
SITES OVERNIGHT. WINDS WILL ALSO CONTINUE TO DECREASE THROUGH THIS
EVENING. CHURCH
&&
.PRELIMINARY POINT TEMP/POPS...
FRI SAT SUN MON TUE WED THU
-----------------------------------------------------------
BIL 043/075 050/084 054/069 048/071 048/068 047/055 043/052
00/U 00/U 12/T 11/B 02/T 23/W 44/W
LVM 034/078 042/086 047/065 042/068 043/065 043/048 038/047
00/U 00/N 22/T 11/B 12/T 23/W 44/W
HDN 038/078 046/086 051/073 046/073 045/073 047/059 044/054
00/U 00/U 02/T 21/B 01/B 13/W 44/W
MLS 040/075 049/084 054/075 051/075 050/075 050/063 047/057
00/U 00/U 02/T 21/U 11/B 13/W 44/W
4BQ 038/074 044/084 053/076 046/074 046/074 047/065 046/056
00/U 00/U 02/T 21/U 11/U 12/W 33/W
BHK 036/070 043/080 050/077 046/073 044/075 045/064 048/057
00/U 00/U 02/T 21/U 11/U 12/W 44/W
SHR 035/076 045/084 050/072 044/071 045/073 044/060 042/051
00/U 00/U 02/T 30/U 01/U 12/W 44/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
122 PM CDT THU SEP 19 2013
.AVIATION...
18Z TAFS FOR KOMA...KOFK...KLNK
SURFACE COLD FRONT AT 18Z EXTENDED FROM SOUTH OF KOMA TO SOUTH OF
KLNK WILL CONTINUE TO MOVE SLOWLY SOUTHEASTWARD THROUGH THE
FORECAST PERIOD. SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED
AT KOMA AND KLNK THROUGH 21Z. SOME STORMS MAY BECOME SEVERE SOUTH
AND EAST OF KLNK THROUGH 19/00Z. CEILINGS ARE EXPECTED TO REMAIN
ABOVE MVFR RANGE IN THUNDERSTORM AREAS. JUST BEHIND THE
FRONT...CEILINGS MAY DROP BRIEFLY INTO MVFR RANGE BEFORE BECOMING
VFR THE REMAINDER OF THE PERIOD.
SMITH
&&
DISCUSSION...
GLANCE AT REGIONAL RADAR ALREADY SHOWING LINE OF CONVECTION FIRING
ALONG INTENSE SFC BAROCLINIC ZONE EXTENDING FROM ABOUT NRN MN TO
NWRN KS. BNDRY IN ASSOCIATION WITH UPPER SHORTWAVE TROF MIGRATING
ACROSS THE NRN PLAINS. AGEOSTROPHIC LIFT JUST AHEAD OF RELATIVELY
DEEP FRONTOGENESIS BNDRY IS QUITE STOUT...PER RUC13. ALSO...STRONG
UPPER LEVEL DIVG ASSOCIATE WITH RRQ OF JET MAX ALOFT CONTRIBUTING TO
ENHANCEMENT OF SYNOPTIC LIFT AS WELL.
SHORT TERM ISSUE IS TIMING THE FRONTAL PASSAGE/PCPN THRU THE CWA.
REGIONAL RADAR WAS SHOWING AN OUTFLOW BNDRY ASSOCIATED WITH CLUSTER
OF STORMS IN WRN NEB WAS QUICKLY PUSHING EAST...AND WILL PROBABLY
REACH THE CWA IN THE NEXT COUPLE HOURS. AT ANY RATE...SFC WIND PROGS
VIA TIME-SERIES INDICATE LEADING EDGE OF THE TRUE FRONT REACHING
KOFK BY LATE MORNING...THEN EARLY AFTN AT KLNK AND KOMA...THUS
APPROXIMATE TIME FRAME FOR FOR EXPECTED CONVECTION. MEANWHILE...
PERSISTENT MOISTURE ADV INTO THE REGION THE LAST 24 HRS HAS
CULMINATED IN A MOISTURE RICH ENVIRONMENT AS SEE BY PWS VALUES
RANGING ANYWHERE FROM 160%-220% ABOVE NORM AHEAD OF THE FRONT. AT
THIS POINT SUSPECT THAT PCPN INTENSITY WILL INCREASE THIS AFTN OVER
SRN CWA WHERE THE RUC13 IS SHOWING PRECIP EFFICIENCY/WARM CLOUD DEPTH
PEAKS. IMPROVING CONDITIONS THEN TONIGHT AS STABLE AIRMASS ENVELOPS
THE REGION. IN CASE OF LINGERING PCPN ACTIVITY...WILL MAINTAIN TOKEN
EVENING POPS SOUTH.
EXCELLENT WEATHER ON TAP THIS WEEKEND IN RESPONSE TO UPPER RIDGE
BUILDING OVER THE PLAINS.
NEXT ROUND OF PCPN COMES SUNDAY NIGHT/MONDAY WHEN NEXT POTENT
SHORTWAVE TROF EXITS THE ROCKIES AND SWEEPS ANOTHER COLD FRONT INTO
THE CNTRL PLAINS. WITH GFS AND ECM IN AGREEMENT DECENT LLVL
MOISTURE FEED PRECEDING THE FRONT...GENEROUS RAINFALL AMOUNTS WILL
ONCE AGAIN BE POSSIBLE.
DEE
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
327 PM CDT THU SEP 19 2013
.DISCUSSION...WATER VAPOR SATELLITE/UPPER AIR PROFILER/WSR-88D VAD
WIND PROFILE TRENDS STILL PLACE AN UPPER LEVEL RIDGE AXIS OVER THE
SOUTHEAST UNITED STATES THIS AFTERNOON. THIS IS RESULTING IN
ACROSS THE MID SOUTH WITH ISOLATED TO SCATTERED SHOWER AND
THUNDERSTORM ACTIVITY THUS FAR LIMITED TO PORTIONS OF
CENTRAL/NORTH CENTRAL ARKANSAS AND SOUTH CENTRAL/SOUTHEAST
MISSOURI. TEMPERATURES AS OF 3 PM CDT ARE IN THE MIDDLE TO UPPER
80S AT MOST LOCATIONS. SHOWER AND THUNDERSTORM CHANCES ASSOCIATED
WITH AN APPROACHING COLD FRONT IS THE MAIN FORECAST CHALLENGE IN
THIS AFTERNOON/S FORECAST.
SHORT TERM MODELS INCLUDING THE 3KM HRRR INDICATE SHOWERS AND
THUNDERSTORMS LOCATED OVER PORTIONS OF ARKANSAS AND SOUTHERN
MISSOURI WILL WEAKEN AND DIMINISH WITH THE LOSS OF DAYTIME HEATING
THIS EVENING. THERE IS A POSSIBILITY THAT SOME OF THIS ACTIVITY
MAY REACH AREAS WEST OF THE MISSISSIPPI RIVER THIS EVENING AND
LEFT ISOLATED SHOWERS AND THUNDERSTORMS IN THE FORECAST. HOWEVER...THINK
BETTER SHOWER/THUNDERSTORM CHANCES WILL HOLD OFF UNTIL LATER
TONIGHT AS THE RIDGE MOVES FURTHER EAST AND MID LEVEL HEIGHT FALLS
WEAKEN SLIGHTLY.
A COLD FRONT CURRENTLY LOCATED OVER THE UPPER MIDWEST AND CENTRAL
PLAINS THIS AFTERNOON WILL DROP INTO THE LOWER MISSISSIPPI VALLEY
ON FRIDAY. MODEST MID LEVEL HEIGHT FALLS AND INSTABILITY WILL
ALLOW FOR SHOWERS AND THUNDERSTORMS TO OVERSPREAD THE MID SOUTH
MAINLY ALONG AND WEST OF THE MISSISSIPPI RIVER FRIDAY MORNING AND
SPREAD EAST TO THE REMAINDER OF THE FORECAST AREA FRIDAY AFTERNOON
INTO FRIDAY NIGHT.
NOT OVERLY IMPRESSED WITH STRONG/SEVERE THUNDERSTORM POTENTIAL AS
OVERALL SHEAR...INSTABILITY...AND FORCING WILL REMAIN ON THE WEAK
SIDE. LATER SHIFTS WILL MONITOR SHORT TERM TRENDS AND ADD STRONG
THUNDERSTORM MENTION IN THE HAZARDOUS WEATHER OUTLOOK IF
CONDITIONS BECOME MORE FAVORABLE AS THE FRONT APPROACHES. OVERALL
RAINFALL AMOUNTS THROUGH FRIDAY NIGHT MAY AVERAGE AROUND ONE HALF
INCH WITH LOCALIZED AMOUNTS UP TO PERHAPS 1.5-2 INCHES ALONG AND
WEST OF THE MISSISSIPPI RIVER...AND LESSER AMOUNTS TOWARDS THE
TENNESSEE RIVER. THE 12Z GFS HAS REMAINED ON THE QUICKER SIDE OF
MODEL SOLUTIONS TODAY AND LEANED FORECAST TOWARDS THE WRF/ECMWF
WHICH SUGGEST FRONTAL PASSAGE FRIDAY AFTERNOON/FRIDAY NIGHT.
LINGERING SHOWERS AND THUNDERSTORMS MAY PERSIST ON SATURDAY...ESPECIALLY
ACROSS NORTHEAST MISSISSIPPI AS THE FRONT SLOWS BEFORE DEPARTING
THE FORECAST AREA BY SATURDAY NIGHT. COOLER AND DRIER AIR WILL
FILTER IN BEHIND THE FRONT RESULTING IN A PERIOD OF MAINLY RAIN
FREE WEATHER ACROSS THE MID SOUTH THROUGH AT LEAST EARLY NEXT
WEEK AND TEMPERATURES AVERAGING NEAR NORMAL FOR SEPTEMBER. 12Z
GFS/ECMWF INDICATE SOME MODEL RUN TO RUN CONTINUITY ISSUES WITH
THE APPROACH OF AN UPPER LEVEL TROUGH OVER THE
PLAINS/MIDWEST...A BUILDING RIDGE OVER THE LOWER MISSISSIPPI
VALLEY AND THE POTENTIAL FOR WEAK SOUTHERLY LOW LEVEL RETURN FLOW
FROM THE GULF OF MEXICO PRODUCING SHOWERS AND THUNDERSTORMS. WILL
KEEP REMAINDER OF FORECAST NEXT WEEK DRY FOR NOW UNTIL MODELS
COME INTO BETTER AGREEMENT.
CJC
&&
.AVIATION...
18Z TAF CYCLE
VFR CONDS WILL PREVAIL THROUGHOUT THE PERIOD. A FEW SHOWERS AND
THUNDERSTORMS MAY DEVELOP THIS AFTERNOON BUT COVERAGE IS NOT
EXPECTED TO BE ENOUGH TO INCLUDE IN TAFS. WILL AMEND AS NECESSARY
BASED ON RADAR TRENDS. WINDS WILL BE SOUTH AT 8-12 KTS...ONLY
DIMINISHING SLIGHTLY OVERNIGHT IN ADVANCE OF A COLD FRONT. A
BETTER CHANCE OF SHOWERS AND THUNDERSTORMS IS EXPECTED LATE IN THE
FORECAST PERIOD. WILL LIKELY ADD PREVAILING SHOWERS IN LATER
UPDATES...WILL START WITH VCSH AT ALL SITES TOMORROW BETWEEN 10Z
AT JBR AND 16Z AT TUP. MEM AND MKL SHOULD SEE SHOWERS AROUND 14Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 72 84 67 81 / 30 80 70 40
MKL 68 84 65 78 / 20 60 70 30
JBR 70 80 61 78 / 50 90 60 10
TUP 68 87 68 81 / 10 50 90 70
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
130 PM CDT THU SEP 19 2013
.UPDATE...FOR 18Z TAFS.
&&
.AVIATION...
THE MID-SOUTH WILL REMAIN IN THE WARM SECTOR AS A COLD FRONT
APPROACHES. THIS FRONT IS EXPECTED TO MOVE INTO MIDDLE TN LATE
FRIDAY NIGHT. THROUGH THIS PERIOD...LITTLE IMPACT WILL BE FELT
DESPITE MOISTURE SLOWLY INCREASING. STRATA CU ABV 3KFT TODAY
WILL DISSIPATED AFTER SUNSET BUT POSSIBLY RETURN TOWARD SUNRISE
CKV/BNA. SOME EARLY MORNING LIGHT FOG MAY DEVELOP CSV AS WELL.
OVERALL...VFR CONDITIONS WILL DOMINATE THE PERIOD. SOUTH WIND
TODAY MAY BRIEFLY GO ABV 10KNTS.
&&
.PREV DISCUSSION... /ISSUED 851 AM CDT THU SEP 19 2013/
UPDATE...
WARM FRONT WILL CONTINUE TO LIFT NORTHWARD AND AWAY FROM TN TODAY.
MEANWHILE...SFC HIGH WILL ALSO CONTINUE TO MOVE EAST TOWARD THE
ATLANTIC COAST. NO APPRECIABLE UPPER DYNAMICS ARE APPARENT AS THE
UPPER RIDGE AXIS WILL ACTUALLY BE IN CLOSER PROXIMITY TO THE MID
STATE BY LATE THIS AFTERNOON. HOWEVER...SOME WEAK BUT FAVORABLE
CURVATURE AND SHEAR WILL ROTATE ACROSS PORTIONS OF THE AXIS LATER
TODAY. THIS ALL TRANSLATES INTO A SLIGHT CHANCE OF SHOWERS OR
TSTMS ACROSS NORTHERN AREAS.
TEMPERATURES SHOULD BE A FEW DEGREES GREATER THAN YESTERDAY.
THUS...UPPER 80S FOR HIGHS STILL LOOKS REASONABLE. HRRR IN LINE
WITH CURRENT FCST THINKING.
ONLY MOD WILL BE TO RERUN ZONES WHICH WILL AUTOMATICALLY REMOVE
THE PATCHY FOG WORDING.
PREV DISCUSSION... /ISSUED 614 AM CDT THU SEP 19 2013/
UPDATE...FOR AVIATION.
AVIATION...
12Z TAFS...VFR CONDITIONS ARE EXPECTED THROUGH MOST OF THIS
PERIOD...THE ONLY EXCEPTION WILL BE SOME POSSIBLE EARLY MORNING
MVFR FOG. SURFACE HIGH PRESSURE ALONG THE EAST COAST WILL PRODUCE
A SOUTH FLOW INTO MID TN WITH SCT-BKN CLOUDS. A STRAY SHRA/TSRA
CANNOT BE RULED OUT...BUT PROB TOO LOW TO INCUDE IN TAFS.
13
PREV DISCUSSION... /ISSUED 355 AM CDT THU SEP 19 2013/
DISCUSSION...
FORECAST REASONING WILL LEAN TOWARD A CONSENSUS MODEL SOLUTION
COMPROMISE FOR THE FORECAST PERIOD UNLESS OTHERWISE NOTED.
FORECAST QUANDARIES...PATCHY FOG POTENTIAL THRU THE MID MORNING
HRS TODAY...SHWR/TSTM CHANCES ESPECIALLY IN ASSOCIATION WITH FRONTAL
PASSAGE FRI NIGHT INTO SAT ALONG WITH POTENTIAL OF THIS BRINGING
HEAVY RAINFALL TO THE MID STATE...OVERALL WX PATTERN SAT NIGHT INTO
THE FIRST PART OF NEXT WEEK...AND TEMPS.
WITH MOST OF THE MID STATE EXPERIENCING CLR SKIES THIS MORNING...AND WITH
TEMPS/DEWPOINTS MAINLY IN THE LOW TO MID 60S ALONG WITH CALM WINDS...DO
EXPECT SOME PATCHY FOG TO FORM IN THE USUAL FOG PRONE LOCATIONS AND NEAR
BODIES OF WATER AND LAST THRU THE MID MORNING HRS. OTHERWISE...WITH RIDGING
INFLUENCES STILL DEPICTED BY MODEL CONSENSUS TO BECOME A LITTLE BIT MORE
ENHANCED THRU THE MORNING HRS ON FRI...WILL ONLY INTRODUCE A SLIGHT CHANCE
OF SHWRS LATE MORNING WITH A SLIGHT CHANCE OF SHWRS/TSTMS BY THE AFTERNOON
HRS WITH AFTERNOON HIGH TEMPS BEING AROUND 5 DEGREES OR SO ABOVE SEASONABLE
NORMAL VALUES UNDER PTCLDY SKIES. HIGHS WILL BE IN THE MID TO UPPER 80S...
LOWER 80S PLATEAU. WILL KEEP THE MID STATE DRY TONIGHT AGAIN UNDER PTCDLY
SKIES WITH THE POSSIBILITY OF YET AGAIN PATCHY FOG ACROSS USUAL FOG PRONE
LOCATIONS AND NEAR BODIES OF WATER THRU THE EARLY MORNING HRS...WITH A
SLIGHT CHANCE OF SHWRS/TSTMS ACROSS WRN PORTIONS OF THE MID STATE THRU THE
MID FRI MORNING HRS WITH THAT PATCHY FOG CONTINUING ACROSS CNTRL AND ERN
PORTIONS OF THE MID STATE DURING THIS TIME PERIOD ALSO. LOWS TONIGHT
ARE EXPECTED TO BE IN THE LOW TO MID 60S...AROUND 60 PLATEAU.
STILL LOOKS LIKE A PRONOUNCED UPPER LEVEL TROUGH WILL DEVELOP TO OUR W IN
ASSOCIATION WITH A SFC COLD FRONT...WITH THEN BOTH APPROACH FRI NIGHT AND
THEN MOVE ACROSS THE MID STATE AS THE DAY PROGRESSES ON SAT. GFS SHOWING
A LITTLE BIT MORE ENHANCED LOW LEVEL JET DYNAMICS MAINLY ACROSS SRN AND
ERN/PLATEAU PORTIONS OF THE MID STATE BY SAT MORNING WITH PRECIP WATER
AMOUNTS APPROACHING AND EVEN SLIGHTLY OVER TWO INCHES. IN LOOKING AT OTHER
FORECAST SOUNDINGS...GFS THE MOST AGGRESSIVE HERE WITH PRECIP WATER VALUES
ALONG WITH THE ABOVE MENTIONED LOW LEVEL JET STRUCTURE AND THUS PRODUCING
SOME HIGH QPF VALUES FOR THE MID STATE FRI NIGHT INTO THE FIRST HALF OF SAT.
IN LOOKING AT LATEST WPC QPF FORECAST ALONG WITH THE OTHER MODELS...AM AT
THIS TIME INCLINED TO BE A LITTLE CONSERVATIVE HERE AS THIS SYSTEM IS NOT
EXPECTED TO BRING A SIGNIFICANT FORCING...INSTABILITY...OR TEMP AIRMASS
CONTRAST WITH IT...THUS WILL GO WITH SLIGHTLY LOWER QPF VALUES THRU THIS
TIME PERIOD. HOWEVER...CAN NOT RULE OUT THE HEAVY RAINFALL POTENTIAL...
BUT THINK AT THIS TIME THAT ANY TYPE OF FLOODING WOULD BE LOCALIZED AND
MINOR AT BEST PER HIGH FFG VALUES AND RAINFALL NOT HAVING BEEN RECEIVED
OVER WIDE AREAS DURING THE PAST FEW DAYS AND WHAT IS EXPECTED TO HAPPEN
UP UNTIL FRI NIGHT. HOWEVER...TO GIVE A HEADS UP POTENTIAL ON THIS HEAVY
RAINFALL POSSIBILITY...WILL GO AHEAD AND MENTION IN THE MORNING`S HWO
ISSUANCE. OTHERWISE...HAVE MENTIONED INCREASING CHANCES OF SHWR/TSTMS E TO
W AS THE DAY PROGRESSES ON FRI WITH THE ABOVE MENTIONED LIMITED INSTABILITY
KEEPING ONLY A CHANCE OF TSTMS THRU FRI NIGHT INTO SAT. HAVE INCREASED POPS
TO CAT MOST LOCATIONS AFTER MIDNIGHT FRI NIGHT...LIKELY S AND PLATEAU...AND
WILL CONTINUE THE TREND OF DECREASING CHANCES OF SHWRS/TSTMS W TO E AS THE
DAY PROGRESSES ON SAT. HIGHS ON FRI WILL CONTINUE THE TREND OF 5 DEGREES OR
SO ABOVE SEASONABLE NORMAL VALUES WITH LOWS FRI NIGHT MAINLY IN THE LOW TO
UPPER 60S...WITH HIGHS ON SAT...AS THE FRONT MOVES THRU ALONG WITH THE UPPER
LEVEL TROUGH...NEAR OR ACTUALLY BELOW SEASONABLE NORMAL VALUES WITH HIGHS
MAINLY IN THE MID TO UPPER 70S.
AS FOR SAT NIGHT INTO THE MID PORTION OF NEXT WEEK...THRU THE FIRST PART
OF NEXT WEEK...WILL TREND CLOSE TO CURRENT FORECAST REASONING WITH
A SLIGHT CHANCE TO CHANCE OF SHWRS ACROSS AT LEAST ERN AND PLATEAU COUNTIES
SAT NIGHT...BUT AM LEANING TOWARD KEEPING THE MID STATE DRY ON SUN WITH
RIDGING INFLUENCES BUILDING ACROSS THE MID STATE PROVIDING DRY CONDITIONS
AND A RETURN TOWARD TEMPS NEAR SEASONABLE NORMS. EVEN THOUGH THERE ARE
SOME TIMING DIFFERENCES IN MODELS...UNLIKE AT THIS TIME YESTERDAY...IT
DOES NOT LOOK LIKE ANY OF THE MODELS ARE ADVERTISING ANY TYPE OF CLOSED
UPPER LEVEL LOW DEVELOPMENT BEHIND THE ABOVE MENTIONED FRONTAL SYSTEM THAT
WOULD SUBSTANTIALLY AFFECT THE MID STATE. THE LATEST EURO DOES DEVELOP A
CLOSED LOW ACROSS CNTRL MS BY MON MORNING BUT MOVES IT WELL SOUTH OF THE
MID STATE AND THEN OPENS IT UP BY TUE...POSSIBLY BRINGING SOME WRAP AROUND
ADDITIONAL MOISTURE TO THE MID STATE DURING THE FIRST PART OF NEXT WEEK.
WITH THIS OVERALL...AND MORE LIKELY TO OCCUR...CHANGE IN CONSENSUS MODEL
SOLUTIONS...WILL GO CLOSE TO CURRENT FORECASTED WX CONDITIONS ACROSS THE
MID STATE DURING THIS TIME PERIOD.
31
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1219 PM CDT THU SEP 19 2013
.UPDATE...AVIATION DISCUSSION.
&&
.PREV DISCUSSION... /ISSUED 1039 AM CDT THU SEP 19 2013/
DISCUSSION...12Z UPPER AIR ANALYSIS PLACES AN UPPER LEVEL RIDGE
AXIS OVER THE SOUTHEAST UNITED STATES THIS MORNING.
CONSEQUENTLY...RAIN FREE WEATHER IS OCCURRING ACROSS THE MID SOUTH
WITH ANY CONVECTIVE ACTIVITY OCCURRING THUS FAR OVER THE OHIO
VALLEY AND PORTIONS OF THE UPPER MID WEST AND NORTHERN/CENTRAL
PLAINS. AS OF 10 AM CDT...TEMPERATURES ARE IN THE UPPER 70S TO
AROUND 80 DEGREES AT MOST LOCATIONS.
LATEST SHORT TERM MODEL TRENDS INDICATE THE POTENTIAL FOR SOME
ISOLATED TO PERHAPS SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP
FROM DAYTIME HEATING ACROSS PORTIONS OF THE MID SOUTH...MAINLY
ALONG AND WEST OF THE MISSISSIPPI RIVER WHERE BETTER LOW LEVEL
MOISTURE RESIDES. AT THIS TIME...FEEL THE LATEST 3KM HRRR AND RUC
MAY BE HANDLING THE CONVECTIVE POTENTIAL THE BEST. WILL UPDATE
FORECAST TO ADJUST POPS ACCORDINGLY...AND MAKE ADJUSTMENTS TO
TEMPERATURES...CLOUD COVER AND ALL OTHER ELEMENTS AS NEEDED.
UPDATED GRIDS WILL BE AVAILABLE SHORTLY.
CJC
PREV DISCUSSION... /ISSUED 709 AM CDT THU SEP 19 2013/
DISCUSSION...
UPDATED FOR 12Z AVIATION DISCUSSION
PREV DISCUSSION... /ISSUED 350 AM CDT THU SEP 19 2013/
SKIES ARE MOSTLY CLEAR ACROSS MUCH OF THE FORECAST AREA THIS
MORNING WITH TEMPERATURES RANGING FROM THE MID 60S TO MID 70S.
TODAY SHOULD BE FAIRLY SIMILAR TO YESTERDAY WITH SOME SCATTERED
THUNDERSTORMS FORMING MAINLY DURING THE AFTERNOON HOURS ACROSS THE
NORTHERN HALF OF THE FORECAST AREA. TEMPERATURES WILL REMAIN QUITE
WARM AGAIN TODAY WITH HIGHS IN THE MID 80S TO AROUND 90 DEGREES.
BY TONIGHT...A COLD FRONT WILL BE MOVING THROUGH THE CENTRAL
PLAINS AND INTO SOUTHWEST MISSOURI. AHEAD OF THE FRONT SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO DEVELOP WITH SOME OF THIS ACTIVITY
REACHING MAINLY WESTERN SECTIONS OF THE FORECAST AREA. ON FRIDAY
THE COLD FRONT WILL START MOVING THROUGH ARKANSAS SO THE CHANCE OF
RAIN WILL INCREASE OVER THE FORECAST AREA WITH THE BEST CHANCE OF
THUNDERSTORMS WEST OF THE MISSISSIPPI RIVER.
THIS MODEL RUN SEEMS TO BRING THE COLD FRONT THROUGH THE FORECAST
AREA FASTER THAN PREVIOUS RUNS SO THAT THE FRONT WILL BE JUST
ABOUT OUT OF THE REGION BY SATURDAY MORNING. FRIDAY NIGHT SHOULD
BE QUITE WET AS THE FRONT MOVES THROUGH. ON SATURDAY RAIN CHANCES
WILL DIMINISH FROM NORTHWEST TO SOUTHEAST AS COOLER AND DRIER AIR
BEGIN TO MOVE IN. TEMPERATURES ON SATURDAY WILL BE A FEW DEGREES
COOLER THAN NORMAL WITH HIGHS AROUND 80 DEGREES EXPECTED FOR MUCH
OF THE FORECAST AREA.
BY SATURDAY NIGHT...THE EXTREME SOUTHEAST CORNER OF THE FORECAST
AREA IS THE ONLY AREA THAT MIGHT SEE AN ISOLATED SHOWER. BY SUNDAY
HIGH PRESSURE WILL IN CONTROL OF THE WEATHER FOR MUCH OF THE EASTERN
U.S. INCLUDING THE FORECAST AREA. THIS WILL MEAN ANOTHER PERIOD OF
DRY WEATHER FROM SUNDAY THROUGH WEDNESDAY. TEMPERATURES WILL
REMAIN SLIGHTLY BELOW NORMAL SUNDAY AND MONDAY BUT WINDS SHOULD
BEGIN TO SHIFT TO THE SOUTH BY TUESDAY ALLOWING FOR WARMER AIR TO
RETURN TO THE REGION WITH ABOVE NORMAL TEMPERATURES EXPECTED FOR
TUESDAY AND WEDNESDAY.
ARS
.AVIATION...18Z TAF CYCLE
VFR CONDS WILL PREVAIL THROUGHOUT THE PERIOD. A FEW SHOWERS AND
THUNDERSTORMS MAY DEVELOP THIS AFTERNOON BUT COVERAGE IS NOT
EXPECTED TO BE ENOUGH TO INCLUDE IN TAFS. WILL AMEND AS NECESSARY
BASED ON RADAR TRENDS. WINDS WILL BE SOUTH AT 8-12 KTS...ONLY
DIMINISHING SLIGHTLY OVERNIGHT IN ADVANCE OF A COLD FRONT. A
BETTER CHANCE OF SHOWERS AND THUNDERSTORMS IS EXPECTED LATE IN THE
FORECAST PERIOD. WILL LIKELY ADD PREVAILING SHOWERS IN LATER
UPDATES...WILL START WITH VCSH AT ALL SITES TOMORROW BETWEEN 10Z
AT JBR AND 16Z AT TUP. MEM AND MKL SHOULD SEE SHOWERS AROUND 14Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 91 72 85 68 / 20 30 80 70
MKL 90 68 85 64 / 20 20 60 70
JBR 92 71 82 63 / 20 30 90 50
TUP 90 68 88 70 / 10 10 50 80
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$