Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/09/15
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
225 PM MST MON SEP 7 2015
.SYNOPSIS...
ISOLATED SHOWERS AND THUNDERSTORM EXPECTED TODAY WITH TEMPERATURES
NEAR NORMAL. MOISTURE LEVELS ARE EXPECTED TO INCREASE TUESDAY THROUGH
THURSDAY...ESPECIALLY FOR SOUTHEASTERN CALIFORNIA AND THE YUMA
VICINITY. BY THE END OF THE WEEK TEMPERATURES WILL BE INCREASING WITH
MUCH LOWER CHANCES FOR ANY STORMS.
&&
.DISCUSSION...
MOISTURE LEVELS ARE ON THE INCREASE ACROSS THE REGION AS OUTFLOW FROM
HURRICANE LINDA OFF THE BAJA CALIFORNIA COAST IS STARTING TO SURGE
INTO THE DESERT SOUTHWEST. WATER VAPOR SATELLITE IMAGERY CLEARY SHOWS
THE WESTERN EDGE OF THE MOISTURE SURGE AS STRETCHING FROM SOUTHEAST
CA UP TO NORTHERN COCONINO COUNTY IN ARIZONA WITH THE MOISTURE PLUME
SURGING ALL THE WAY TO THE NORTHEAST INTO UTAH AND COLORADO. SHOWER
ACTIVITY IS BUILDING UP ACROSS ARIZONA WITH THE GREATEST ACTIVITY IN
YAVAPAI AND COCONINO COUNTIES AT THIS TIME. THE EXTENSIVE CLOUD COVER
ACROSS THE GREATER PHOENIX AREA IS HELPING DAMPEN THE TEMPERATURE
SOMEWHAT WITH A HIGH SO FAR OF 97 IN PHOENIX TWO HOURS AGO. WEBCAMS
AND RADAR INDICATE SOME LIGHT SHOWERS ACROSS THE VALLEY EARLY THIS
AFTERNOON. SOME CLEARING IS EVIDENT IN SOUTHWEST MARICOPA COUNTY ON
THE VISIBLE SATELLITE IMAGERY AS OF 2 PM AND THIS CLEARING SHOULD
REACH THE PHOENIX AREA BY LATE AFTN.
MODELS INDICATE THE MOISTURE SURGE WILL CONTINUE THROUGH LATE
WEDNESDAY. THE HRRR IN PARTICULAR IN THE SHORT TERM IS DEVELOPING A
LINE OF MODERATE RAIN AND THUNDERSTORMS ACROSS NORTHERN
YUMA...SOUTHEAST LA PAZ...AND NORTHWEST MARICOPA COUNTY LATER THIS
EVENING AS WELL AS MORE ACTIVITY FOR SOUTHERN MARICOPA AND PINAL
COUNTIES. HIGH PRESSURE WILL BEGIN TO MOVE BACK OVER THE SOUTHWEST BY
FRIDAY SETTLING OVER SOUTHERN NEVADA ...LARGELY CUTTING OFF THE
TROPICAL MOISTURE FLOW AND DROPPING CHANCES FOR RAIN AND INCREASING
TEMPERATURES FOR THE WEEKEND.
&&
.PREVIOUS DISCUSSION...
TODAY AND TUESDAY...
SATELLITE AND RADAR DATA EARLY THIS MORNING SHOW DEBRIS CLOUDS WITH
SOME EMBEDDED SHOWERS AND EVEN A STRAY THUNDERSTORM DEVELOPING OVER
SOUTH-CENTRAL ARIZONA. THE LATEST MODELS HAVE ALL BEEN INDICATING
THIS TO VARYING DEGREES. THUS HAVE SLIGHT CHANCE POPS GOING ALL DAY
OVER THE LOWER DESERTS OF SOUTH-CENTRAL ARIZONA...THOUGH THICKER
CLOUDS WILL LIKELY NOT HANG AROUND ALL DAY. NUDGED FORECAST TEMPS
DOWN SLIGHTLY FROM PREVIOUS PACKAGE TO ACCOUNT FOR MORE CLOUD COVER
DESPITE THE WESTWARD EXPANSION OF HIGH PRESSURE. SATURATED LAYERS
LOOK TO BE EVEN THICKER EAST OF METRO PHOENIX FOR HIGHER POPS
THERE...DESPITE LITTLE MODEL CAPE. IN FACT BEST MODEL CAPE FOR OUR
FORECAST AREA CONTINUES TO BE OVER SOUTHWEST ARIZONA BUT NOT REALLY
LOOKING AT MUCH DIFFERENCE FROM YESTERDAY. THUS POPS REMAIN MODEST
TODAY. OVERALL MODELS NOT INDICATING MUCH IMPROVEMENT IN MOISTURE
AND CAPE FOR TUESDAY. THOUGH THERE SHOULD BE LESS CLOUDINESS...IT
WILL TEND TO BE OFFSET BY THE EXPANDING RIDGE AND ASSOCIATED
ANTICYCLONIC FLOW.
WEDNESDAY AND THURSDAY...
LATEST MODELS ARE INDICATING THAT MOISTURE FROM HURRICANE LINDA WILL
MOVE INTO THE AREA WEDNESDAY. LINDA WILL REMAIN OFF THE BAJA COAST
BUT WILL BE CLOSE ENOUGH SUCH THAT THERE LOOKS TO BE BOTH A GULF
SURGE AND MID AND HIGH CLOUDS MOVING IN. GFS IS MORE AGGRESSIVE WITH
THE CLOUDINESS THAN NAM WITH ECMWF IN BETWEEN. THERE MAY BE TOO MUCH
CLOUDINESS TO DESTABILIZE ENOUGH FOR FULL FLEDGED THUNDERSTORMS OR
EVEN CONVECTIVE SHOWERS...ESPECIALLY IF GFS IS CORRECT. THIS IS
REFLECTED IN THE MODEL CIN WHICH REMAINS FAIRLY HIGH. THUS DESPITE
THE MOISTURE...POPS REMAIN QUITE MODEST. A CAVEAT IS THAT THERE MAY
BE A PERTURBATION IN THE FLOW...AS DEPICTED BY GFS...WHICH CLOUD
POSSIBLY AID IN SHOWER DEVELOPMENT. IF ANY CONVECTION MANAGES TO
DEVELOP IT WILL BE VERY EFFICIENT AT RAIN PRODUCTION. WITH MORE
HUMIDITY AND CLOUDINESS AROUND...HIGH TEMPS WEDNESDAY WILL BE A BIT
LOWER...ESPECIALLY OVER SOUTHWEST ARIZONA AND THE LOWER COLORADO
RIVER VALLEY. ON THURSDAY...DIFFERENCES BETWEEN GFS AND ECMWF BECOME
MORE DISTINCT. ONE KEY AREA IS IN MOISTURE AND CAPE. THE GFS STARTS
TRENDING DOWN WHILE THE ECMWF HANGS ON TO HIGHER VALUES...EVEN THOUGH
THEY HAVE ROUGHLY SIMILAR POSITIONS FOR THE MAIN ANTICYCLONIC AND
CYCLONIC CIRCULATIONS...INCLUDING LINDA. HELD ON TO MODEST POPS AS
UPPER LEVEL WEST-NORTHWESTERLY FLOW LOOKS TO BE FAIRLY CONFLUENT.
FRIDAY THROUGH SUNDAY...
THE FLOW BECOMES MORE AMPLIFIED LATE IN THE WEEK. WITH A NORTHERLY
COMPONENT TO THE FLOW...A DRYING TREND IS EXPECTED. NOT SURPRISINGLY THE
ECMWF IS MORE RELUCTANT TO DRY THINGS OUT. THE POPS DROP OUT FOR MOST
PLACES BY FRIDAY AND EVERYWHERE BY SUNDAY. OF NOTE...AN INVERTED
TROUGH IS ADVERTISED TO MOVE THROUGH NEW MEXICO AND ACROSS NORTHWEST
MEXICO OVER THE WEEKEND. THE GFS KEEPS IT A BIT FURTHER EAST THAN
ECMWF. TAKING A BLENDED APPROACH...AND IN ACKNOWLEDGEMENT OF MUCH OF
THE TEMPERATURE GUIDANCE...NUDGED TEMPS DOWN SLIGHTLY FROM PREVIOUS
PACKAGE. STILL LOOKING AT TEMPERATURES CLIMBING AT LEAST A FEW
DEGREES ABOVE NORMAL...EVEN MORE SO OVER SOUTHWEST ARIZONA AND
SOUTHEAST CALIFORNIA.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
BAND OF SHOWERS WILL CONTINUE TO MOVE NORTH ACROSS THE PHOENIX AREA
THIS AFTERNOON...MOST CIGS SHOULD BE ON THE HIGH SIDE...AOA 12K FEET
OR SO...WITH SOME HIGH BASED CU IN THE AREA AS WELL. SO FAR IT
APPEARS SOMEWHAT STABLE SO THREAT FOR THUNDERSTORMS IS DIMINISHED
AND DUE TO LOW CONFIDENCE NO MENTION OF STORMS WILL BE MADE IN THE
CURRENT TAF PACKAGE. SHOULD CONVECTION BECOME MORE INTENSE LATER WE
CAN UDDATE TAFS FOR THE INCREASED THREAT OF THUNDER. OTHERWISE
CONSIDERABLE MID/HIGH CLOUD DECKS EXPECTED THIS EVENING INTO THE
MORNING HOURS TOMORROW WITH BROKEN CIGS AOA 14K LIKELY AFTER
MIDNIGHT. WINDS GENERALLY LIGHT AND DIURNAL NEXT 24 HOURS.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
THREAT FOR SHOWERS/STORMS NEXT 24 HOURS QUITE LOW...MOSTLY AOB 10
PERCENT SO NO MENTION WILL BE MADE IN THE TAFS. MOSTLY LOOKING AT
SCT TO BKN MID/HIGH LEVEL CLOUD DECKS AT TIMES. WINDS ON THE LIGHT
SIDE FAVORING S/SW DIRECTIONS THROUGH TUESDAY AFTERNOON. A FEW
STORMS MAY DEVELOP ALONG THE NRN BAJA SPINE AND TRY TO MOVE INTO
SWRN IMPERIAL COUNTY BUT CONFIDENCE LOW THAT THEY WILL AFFECT THE
KIPL TERMINAL.
BETTER CHANCES FOR SHOWERS OR THUNDERSTORMS AS WE MOVE INTO THE
MIDDLE OF THE WEEK AS TROPICAL MOISTURE FROM LINDA SPREADS INTO THE
AREA FROM THE SOUTH.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
THURSDAY THROUGH MONDAY...SLIGHT THUNDERSTORM CHANCES WILL CONTINUE
AREAS-WIDE THURSDAY...TAPERING OFF TO NEARLY NEGLIGIBLE CHANCES BY
THE WEEKEND. CONFIDENCE IS HIGHER THAT MOISTURE FROM TROPICAL STORM
LINDA WILL SPREAD INTO THE DESERTS FROM THE SOUTH THROUGH MIDWEEK
CAUSING AN INCREASE IN STORM CHANCES...AND A MARKED INCREASE IN
HUMIDITY LEVELS. MINIMUM RH VALUES WILL MOSTLY RANGE BETWEEN 20 AND
30 PERCENT THURSDAY...LOWERING INTO THE TEENS OVER THE WEEKEND.
OVERNIGHT RECOVERIES WILL BE GOOD AT MOST LOCATIONS THROUGH THE
PERIOD. NEAR SEASONAL NORMAL HIGH TEMPERATURES THURSDAY WILL CLIMB
AND BY THE WEEKEND AS THE AIRMASS DRIES WE CAN EXPECT WELL ABOVE
SEASONAL NORMAL READINGS WITH HIGHS REACHING OR EXCEEDING 110
DEGREES OVER THE WESTERN DESERTS OF SOUTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA. WINDS WILL FAVOR A WEST TO SOUTHWEST DIRECTION IN THE
AFTERNOON...WITH THE TYPICAL LIGHT DRAINAGE COMPONENT OVERNIGHT.
&&
&&
.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION IS NOT EXPECTED.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...WATERS
AVIATION...CB
FIRE WEATHER...CB
AREA FORECAST DISCUSSION
NWS TUCSON AZ
1005 AM MST MON SEP 7 2015
.SYNOPSIS...EXPECT SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS THROUGH TUESDAY. A DRYING TREND WILL LIKELY BEGIN
WEDNESDAY...WITH SHOWERS AND THUNDERSTORMS CONFINED MAINLY NEAR THE
EASTERN MOUNTAINS BY THIS WEEKEND. DAYTIME TEMPERATURES WILL
GENERALLY BE WITHIN A FEW DEGREES OF NORMAL THIS WEEK.
&&
.DISCUSSION...A FEW SHOWERS AND THUNDERSTORMS WERE OCCURRING ACROSS
FAR WESTERN PIMA COUNTY AT THIS TIME. THESE SHOWERS/TSTMS APPEAR TO
BE ASSOCIATED WITH A WEAK CYCLONIC CIRCULATION FEATURE OVER THE NRN
GULF OF CALIFORNIA. THERE IS ALSO AN AXIS OF INSTABILITY AS PER SPC
MESOSCALE ANALYSIS THAT EXTENDS FROM SW ARIZONA SEWD INTO WEST
CENTRAL SONORA. A JET STREAK ALSO EXTENDED FROM SOUTH CENTRAL AZ
INTO NRN ARIZONA...WITH THE ONGOING CONVECTION ASSOCIATED WITH THE
RIGHT ENTRANCE REGION OF THE WEAK JET STREAK.
OTHERWISE...MOSTLY SUNNY SKIES PREVAILED ACROSS ERN SECTIONS WITH
PARTLY CLOUDY TO CLOUDY SKIES FROM TUCSON WWD INTO WRN PIMA COUNTY.
07/12Z KTWC SOUNDING TOTAL PRECIP WATER VALUE WAS 1.56 INCHES. THE
SOUNDING DEPICTED A PRONOUNCED WARM LAYER AROUND 400 MB. MODERATE
SWLY FLOW CONTINUED ABOVE 500 MB.
ADDITIONAL SHOWER/TSTM DEVELOPMENT SHOULD OCCUR DURING THE NEXT 1-2
HOURS WEST OF TUCSON IN RESPONSE TO THE DIAGNOSTIC FEATURES NOTED
ABOVE. SEVERAL HRRR SOLUTIONS AND THE 07/12Z WRF-NAM SUGGEST THAT
SHOWERS/TSTMS ELSEWHERE WILL BE LIMITED TO MAINLY NEAR THE MOUNTAINS
THIS AFTERNOON AND EVENING. THE OFFICIAL FORECAST WAS UPDATED FOR
THE ONGOING SHOWERS/TSTMS ACROSS WRN SECTIONS...AND SOME DOWNWARD
POP ADJUSTMENTS WERE MADE MOSTLY FOR THE LOWER ELEVATIONS BASED ON
THE HRRR AND UNIV OF AZ WRF-NAM SOLUTIONS.
AT ANY RATE...ISOLATED TO SCATTERED SHOWERS/TSTMS WILL PREVAIL THIS
AFTERNOON/EVENING FOLLOWED BY A SLIGHT CHANCE OF SHOWERS/TSTMS LATE
TONIGHT. HIGH TEMPS TODAY WILL BE QUITE CLOSE TO TEMPS ACHIEVED
SUN...AND WILL GENERALLY BE WITHIN A FEW DEGS OF NORMAL.
PLEASE REFER TO THE ADDITIONAL SECTIONS FOR FURTHER DETAIL.
&&
.AVIATION...VALID THRU 08/18.
ISOLATED -TSRA/-SHRA WILL OCCUR WEST OF KTUS THIS MORNING. ISOLATED
TO SCATTERED -TSRA/-SHRA WILL THEN OCCUR ELSEWHERE THIS AFTERNOON
AND EVENING. ISOLATED -TSRA/-SHRA SHOULD THEN CONTINUE LATE TONIGHT
INTO TUESDAY MORNING. OTHERWISE...SCATTERED TO OVERCAST CLOUDS
GENERALLY RANGING FROM 10-15K FT AGL AND SURFACE WIND MAINLY LESS
THAN 10 KTS WILL PREVAIL INTO TUESDAY MORNING. AVIATION DISCUSSION
NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL
OCCUR THROUGH WEDNESDAY. A DRYING TREND IS THEN EXPECTED TO BEGIN
THURSDAY...WITH ISOLATED SHOWERS AND THUNDERSTORMS BECOMING LIMITED
TO MAINLY NEAR THE NEW MEXICO BORDER THIS WEEKEND. BRIEF STRONG...
GUSTY AND ERRATIC WINDS WILL OCCUR WITH THE STRONGER THUNDERSTORMS.
OTHERWISE...20-FOOT WINDS WILL BE MAINLY TERRAIN DRIVEN AND LESS
THAN 15 MPH.
&&
.PREV DISCUSSION /320 AM MST/...
TUESDAY...LOW LEVEL SURGE OF MOISTURE CONTINUES UP THE GLFCA AS WITH
TS LINDA W OF THE SRN TIP OF BAJA. ACROSS SE AZ...PW VALUES REMAIN
IN THE 1"-1.50" RANGE WHILE MID-LVL FLOW BECOME A BIT MORE WLY. WILL
MAINTAIN SLIGHT CHANCE TO CHANCE TYPE POPS ACROSS THE AREA.
WEDNESDAY...LOW LEVEL MOISTURE SURGES INTO THE LOWER DESERTS WITH PW
VALUES UP TO AROUND 2" ACROSS SW AZ AND 1.50" ACROSS SE AZ.
INCREASED POPS A BIT OUT IN WRN PIMA COUNTY...BUT LATER SHIFTS WILL
HAVE TO WATCH MODEL TRENDS FOR WEDNESDAY NIGHT PERIOD. THIS IS BASED
ON NEW 06Z NAM RUN WHICH INCREASE ELY FLOW ALOFT OVER THE AREA WED
NIGHT INTO THU MORNING WHILE SWINGING A DISTURBANCE IN FROM THE S.
CONFIDENCE IN THIS SCENARIO IS ON THE LOW SIDE RIGHT NOW.
THURSDAY...UP IN THE AIR AS WEDNESDAY WILL LIKELY DICTATE ON WHAT
WILL BE AROUND TO IMPACT STORM DEVELOPMENT. AGAIN CONFIDENCE IS LOW
FOR THURSDAY...SO WILL MAINTAIN LOW END TYPE POPS FOR NOW.
BASICALLY LOTS OF IFS FOR THE WEDNESDAY/THURSDAY TIME FRAME THUS THE
LOW CONFIDENCE IN THE FORECAST.
FRIDAY INTO SUNDAY...A SIGNIFICANT DOWNTURN IN STORM CHANCES AS FLOW
ALOFT BECOMES MORE NORTHERLY. WILL HOLD ON TO SLIGHT CHANCE POPS FOR
THIS TIME FRAME.
HIGHS THROUGH MOST OF THIS FORECAST CYCLE WILL REMAIN NEAR NORMAL.
HOWEVER WEDNESDAY AND THURSDAY EASILY COULD BE BELOW NORMAL.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
FRANCIS
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1042 PM MDT SUN SEP 6 2015
.UPDATE...
ISSUED AT 1042 PM MDT SUN SEP 6 2015
UPPER JET MAX IS INTERACTING WITH MOISTURE AND INSTABILITY ON TOP
OF THE EML AND ISOLATED SHOWERS/THUNDER HAVE BEEN POPPING OVER THE
NORTHEAST UTAH. HRRR HAS THE BEST HANDLE LATE THIS PM SO WILL RELY
ON IT FOR GUIDANCE OVERNIGHT. POPS CHANGED AS A RESULT.
&&
.SHORT TERM...(TONIGHT THROUGH MONDAY NIGHT)
ISSUED AT 237 PM MDT SUN SEP 6 2015
ISOLATED SHOWERS AND THUNDERSTORMS HAVE FORMED ACROSS HIGHER
TERRAIN AND WITH AVAILABLE MOISTURE STARTING TO DROP...DO NOT
EXPECT COVERAGE TO INCREASE TOO MUCH THIS AFTERNOON. DEWPOINTS ARE
ABOUT 5 DEGREES LOWER THAN YESTERDAY AND THIS DRYING TREND WILL
CONTINUE AS FLOW BECOMES MORE WESTERLY. FOR MOST AREAS
THEN...EXPECT SOME CUMULUS BUILDUP...MAYBE A PASSING SHOWER FOR
THE HIGHER TERRAIN WITH AN OCCASIONAL RUMBLE OF THUNDER AND
SEASONAL TEMPS. MODELS PICKING UP ON A WEAK SHORTWAVE MOVING OVER
THE CWA NEAR 3AM KICKING OFF SOME SHOWERS BUT NOT SOLD ON IDEA SO
KEPT ANY MENTION OF PRECIP OUT OF FORECAST. LATER SHIFTS CAN
REEVALUATE AS NEEDED.
WHILE MONDAY WILL REMAIN PREDOMINANTLY DRY...ENOUGH MOISTURE WILL
LINGER FOR A FEW LATE DAY SHOWERS AND THUNDERSTORMS OVER THE
HIGHER TERRAIN. THE UPPER JET WILL WEAKEN THROUGH THE DAY...AND
GENERALLY WILL NOT PROVIDE MUCH SUPPORT TO THE AFTERNOON
CONVECTION. TEMPERATURES WILL REMAIN NEAR NORMAL FOR EARLY
SEPTEMBER...AT MOST A COUPLE DEGREES WARMER THAN TODAY.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 237 PM MDT SUN SEP 6 2015
A SHORTWAVE WILL PASS TO OUR NORTH ON TUE...WITH LITTLE IMPACT ON
OUR FORECAST AREA. MODELS INDICATE THAT CONVECTIVE ACTIVITY WILL
SHIFT TO THE SOUTH AS DRIER AIR MOVES OVER THE NORTH. THE SAN
JUANS SHOULD SEE A LITTLE BETTER COVERAGE THAN ON MONDAY. BUT
OTHER AREAS WILL EITHER SEE LITTLE CHANGE OR WILL BE DRIER.
BY WED THE SUBTROPICAL RIDGE WILL HAVE SHIFTED WESTWARD...INTO
THE DESERT SOUTHWEST AND ALONG THE WEST COAST. THIS PUTS OUR
FORECAST AREA UNDER A DRIER NORTHWEST FLOW. THE RIDGE WILL
CONTINUE TO BUILD OVER THE WEST COAST THROUGH THE WORK WEEK...THEN
REMAIN PARKED THERE THROUGH NEXT WEEKEND. THEREFORE LITTLE CHANCE
OF SHOWERS AND THUNDERSTORMS WILL BE EXPECTED THROUGH THE
REMAINDER OF THE FORECAST PERIOD. TEMPERATURES WILL WARM TO AROUND
5 DEGREES ABOVE NORMAL FOR THE SECOND HALF OF THE WEEK. NIGHTTIME
LOWS WILL HOVER AROUND NORMAL IN THE DRY AIR MASS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1042 PM MDT SUN SEP 6 2015
VFR CONDITIONS PREVAIL THE NEXT 24 HOURS AT AREA FORECAST
TERMINALS. ISOLATED -SHRA/-TSRA CAN BE EXPECTED IN THE VICINITY OF
KVEL/KGJT/KRIL THROUGH SUNRISE...THEN KASE/KEGE/KTEX WILL HAVE A
SMALL CHANCE THIS AFTERNOON. OVERALL CONFIDENCE...OUTSIDE OF KVEL
THROUGH 07Z...IS LOW AND FORECASTS WILL CONVEY THIS. WILL HAVE TO
WATCH USUAL UPVALLEY/NORTHWEST WINDS AT KASE FOR LANDING ISSUES
THIS AFTERNOON AS WELL.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
UPDATE...15
SHORT TERM...TGR/EH
LONG TERM...EH
AVIATION...TGJT
AREA FORECAST DISCUSSION
NWS TAUNTON MA
717 PM EDT TUE SEP 8 2015
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN SOUTH OF NEW ENGLAND THROUGH MID WEEK.
HOT AND HUMID CONDITIONS ARE EXPECTED WITH HIGH TEMPERATURES
APPROACHING RECORD LEVELS. AN AREA OF LOW PRESSURE WILL LIFT
ACROSS THE REGION THURSDAY INTO FRIDAY BRINGING WITH IT THE THREAT
OF HEAVY RAIN AND LOCALIZED FLOODING. A LULL FOLLOWS FOR SATURDAY
PRIOR TO ANOTHER POTENTIAL BATCH OF RAIN FOR SUNDAY INTO MONDAY. A
WARM AND DRY PATTERN LOOKS TO PREVAIL INTO NEXT WEEK.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
730 PM UPDATE...
SOME MINOR TWEAKS TO THE FORECAST TO ACCOUNT FOR TRENDS AFTER THIS
VERY HOT DAY...THE WARMEST DAY FOR THE ENTIRE SUMMER! A FEW RECORDS
ESTABLISHED...WINTER IS NOT THAT VERY FAR AWAY.
SOME SHOWER ACTIVITY PERSISTING ALONG THE INITIAL LEADING WAVE OF
WHAT LOOKS TO BE PARENT WITH A MID-LEVEL WARM FRONT. LIFTING N/E
WITH THE MEAN-LAYER FLOW AS DAYTIME HEATING DIMINISHES...SHOULD
SEE THAT SHOWER ACTIVITY CONCLUDE AS THE REGION OF MORE FAVORABLE
SHOWER DEVELOPMENT PUSHES ON UP INTO N NEW ENGLAND. ELEVATED
INSTABILITY APPARENT COINCIDENT WITH DECENT K-INDICES AS THE PRIOR
FORECASTER NOTED.
MID-LEVEL DRYING OVERNIGHT APPARENT FROM THE LATEST RAP BUFKIT
PROFILES. MOISTURE-POOLING BENEATH THE SUBSEQUENT INVERSION OF
HIGH DEWPOINT AIR LENDING TO LOW-CLOUDS / FOG DEVELOPMENT MORE
LIKELY OVER SE NEW ENGLAND INCLUDING THE CAPE AND ISLANDS. LATEST
SATELLITE SHOWS A BANK OF LOW CLOUDS SITUATED JUST OFFSHORE OF
NANTUCKET. WILL BE MONITORING THIS CLOSELY ALONG WITH THE MEAN
FLOW. THE CLOUD-BANK MAY NOT NECESSARILY MOVE INTO THE REGION BUT
RATHER EXPAND WITH THE INCREASING MOISTURE CONTENT BENEATH THE
BUILDING INVERSION.
A MILD NIGHT OVERALL WITH DECENT S/SW-FLOW. LOWS AROUND THE MID-
TO UPPER-60S WITH WARMEST READINGS AROUND 70-DEGREES FOR THE URBAN
CENTERS AND S/SE-SHORES.
&&
.SHORT TERM /WEDNESDAY NIGHT/...
WEDNESDAY...
MID LEVEL DRY AIR HANGS ON THROUGH THE MORNING BEFORE COLUMN
MOISTURE GRADUALLY INCREASES DURING THE AFTERNOON AHEAD OF
APPROACHING COLD FRONT. CAPES INCREASE TO ABOUT 1000 J/KG DURING
THE AFTERNOON. HI-RES GUIDANCE KEEPS BULK OF CONVECTION TO THE
NORTH AND WEST THROUGH THE DAY CLOSER TO THE FRONT...BUT LOW PROB
OF A FEW SHOWERS/TSTMS MOVING INTO W MA TOWARD EVENING.
ANOTHER HOT AND HUMID DAY...ESPECIALLY ACROSS NE MA AND CT VALLEY
WHERE TEMPS WILL LIKELY REACH LOWER 90S AND RECORDS AT BOS/BDL MAY
BE APPROACHED. STRONGER SW FLOW AND COOLER 925 MB TEMPS WILL
KEEP THE COASTAL PLAIN AND S COAST A BIT COOLER IN THE MID/UPPER
80S. HOWEVER...DEWPOINTS WILL BE CLIMBING INTO THE LOWER 70S NEAR
THE S COAST WITH UPPER 60S ELSEWHERE SO QUITE HUMID.
WEDNESDAY NIGHT...
COLD FRONT MOVES INTO WESTERN NEW ENG DURING THE EVENING AND MAY
SEE A FEW SHOWERS/TSTMS HERE DURING THIS TIME. IT APPEARS THE
FRONT WILL STALL WEST OF THE I95 CORRIDOR OVERNIGHT AND WILL HAVE
TO WATCH FOR RENEWED CONVECTION DEVELOPING ACROSS SE NEW ENG LATE
WED NIGHT AHEAD OF THE FRONT AS A PIECE OF INSTABILITY OVER THE
OCEAN LIFTS NWD ALONG THE S COAST. MODEST LOW LEVEL JET WILL HAVE
MOVED TO THE EAST BY THEN THUS LIMITING LOW LEVEL FORCING AND
INSTABILITY IS MARGINAL SO CONFIDENCE IS NOT HIGH. ANY SHOWERS OR
TSTMS WILL HAVE POTENTIAL FOR HEAVY RAINFALL AS PWATS INCREASE TO
OVER 2 INCHES.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
HIGHLIGHTS...
* POTENTIAL FOCUSED AREA OF HEAVY RAIN THURSDAY INTO FRIDAY
* THREAT OF URBAN / POOR-DRAINAGE FLOODING OVER NEW ENGLAND
* A LULL PRIOR TO RENEWED ACTIVITY SUNDAY INTO MONDAY
* LOOKING DRY AND WARMER INTO NEXT WEEK
DISCUSSION...
THURSDAY THROUGH FRIDAY...
THERE IS A CONCERN OF A PRONOUNCED AND PROLONGED AREA OF HEAVY RAIN
THAT COULD LEAD TO FLOODING. THOUGH SREF PROB AND ENSEMBLE MEMBERS
VARY...DETERMINISTIC SOLUTIONS AND POINTS OUTLINED BELOW PROVIDE
SOME LEVEL OF ASSURANCE OF AN AREA OF IMPACT ACROSS NEW ENGLAND.
KEEPING IN MIND THAT A MAJORITY OF RIVERS AND STREAMS ARE WELL-BELOW
NORMAL WITH RESPECT TO STREAMFLOWS AS LAKES AND RESERVOIRS ARE LOW
THE SUBSEQUENT FOCUS IS UPON URBAN AND POOR-DRAINAGE FLOODING. MORE
DETAILS BELOW.
PACIFIC-ORIGIN ENERGY STRETCHED THRU THE E-PERIPHERY OF A DOMINANT
GREAT-LAKES TROUGH PATTERN INVOKES AN AREA OF LOW PRESSURE ALONG A
QUASI-STATIONARY FRONTAL BOUNDARY OF GREATER BAROCLINICITY SW-NE IN
PROXIMITY TO S NEW ENGLAND. LOWERING HEIGHTS PARENT WITH THE RRQ OF
THE UPPER-LEVEL JET SITUATED N OF NEW ENGLAND LENDS VENTING-SUPPORT
ABOVE DECENT LOW-MID LEVEL CONVERGENCE OF ANOMALOUSLY HIGH THETA-E
AIR ALONG AND AHEAD OF THE LOW.
AS THE LOW APPROACHES...FOCUS LOOKS FRONTOGENTICAL AROUND H6-8 AS
H925-85 THETA-E CONVERGENT NOSE UPSLOPES REARWARD TOWARDS MORE
FAVORABLE DIVERGENCE. SQUEEZE OF PWATS IN EXCESS OF 2-INCHES COULD
RESULT IN A ROUGHLY SW-NE AREA OF HEAVY RAIN ACROSS NEW ENGLAND.
SOME UNCERTAINTY AS TO WHETHER STORMS DEVELOP OUT AHEAD OF THE
APPROACHING LOW. FEEL CLOUD COVER ALONG THE FRONTAL BOUNDARY WILL
LIMIT DESTABILIZATION. THERE IS ALSO THE THREAT OF A MORNING-PUNCH
OF ACTIVITY SHOULD A LOW-LEVEL JET FOCUS CLOSER WITH A CONVERGENT
NOSE OF THETA-E BUT ALL INDICATIONS LOOK FOR THIS TO BE OFFSHORE. A
LOT OF INTANGIBLES...JUST DOES NOT APPEAR TO BE THE GREATEST SETUP
FOR SEVERE ACTIVITY. NEVERTHELESS MARGINAL INSTABILITY YIELDED BY A
MOISTENING PROFILE COUPLED WITH SHEAR AROUND OR ABOUT 25 KNOTS IN A
CONDITIONALLY-UNSTABLE ENVIRONMENT OF ROUGHLY MOIST-ADIABATIC LAPSE
RATES YIELDS A THUNDERSTORM RISK.
WILL LEAN WITH A SLIGHT-CHANCE TO CHANCE THREAT OF STORMS WITH THE
MARGINALLY UNSTABLE-SHEAR ENVIRONMENT. CAN NOT RULE OUT STRONG
ACTIVITY BUT THINK IT WILL BE ISOLATED. MAIN CONCERN AGAIN IS WITH
THE HEAVY RAIN AND WILL PREVAIL WITH SUCH WORDING IN THE FORECAST.
WILL KEEP WITH HIGH CATEGORICAL POPS AND MODIFY THE HAZARDOUS
WEATHER OUTLOOK TO REFLECT THINKING COHESIVELY WITH THIS DISCUSSION.
TEMPERATURES NEAR-SEASONABLE.
WEEKEND INTO EARLY NEXT WEEK...
TIMING / MORPHOLOGY / EVOLUTION OF THE GREAT-LAKES MID-UPPER LEVEL
TROUGH DISTURBANCE UNDER SCRUTINY. WILL YIELD TO ENSEMBLE MEANS WITH
RESPECT TO OUTCOMES. PARENT SURFACE LOW TO THE DEAMPLIFYING OPEN-
WAVE SETUP LOOKS TO LIFT ALONG A FRONTAL BOUNDARY BEING PUSHED OFF-
SHORE BY THE WAVE MONDAY. INCREASING RAIN CHANCES SUNDAY WITH THE
LOW APPROACH AS THE SURFACE SYNOPTICS LOOK TO COUPLE WITH THE UPPER-
LEVEL JET AND DECENT MID-LEVEL FORCING / THETA-E CONVERGENCE. THERE
APPEARS TO BE A GOOD CHANCE OF RAIN BUT IT IS POSSIBLE THAT THE
SYSTEM AS A WHOLE REMAINS MORE S AND E. WITH UNCERTAINTY / SCRUTINY
WILL KEEP WITH CHANCE POPS WITH NEAR-SEASONABLE TEMPERATURES. LOOKS
TO BE SOME EMBEDDED THUNDER IN THE MIX WITH THE POTENTIAL THREAT OF
HEAVY RAIN TO GO ALONG WITH IT.
NEXT WEEK...
ENSEMBLE SOLUTIONS SIGNALLING A RETURN TO A RIDGING PATTERN. COULD
BE LOOKING AT ANOTHER PRONOUNED HOT-HUMID PERIOD AS HIGH PRESSURE
BUILDS S/E OF THE REGION RESULTING IN A PREVAILING SW-FLOW ALOFT.
LOW CONFIDENCE IN THE FORECAST AT THIS TIME TILL THE WEEKEND DETAILS
BECOME MORE IRONED OUT.
&&
.AVIATION /23Z TUESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH WEDNESDAY NIGHT/...
0Z UPDATE...
TONIGHT...MODERATE CONFIDENCE.
WILL BE A BIT MORE OPTIMISITC. FOCUS OF IFR-LIFR ACROSS S/SE-
COASTAL TERMINALS ESPECIALLY ACK. CAN NOT RULE OUT PATCHY FOG
DEVELOPMENT ACROSS THE INTERIOR BUT FEEL GREATER LIKELIHOOD IS
TOWARDS THE COAST.
WEDNESDAY...MODERATE CONFIDENCE. LEFTOVER IFR CIGS/VSBYS SHOULD
IMPROVE BY MID MORNING...BUT MAY LINGER INTO THE AFTERNOON OVER
ACK. OTHERWISE...VFR. S-SW WIND GUSTS TO 20-25 KT DEVELOPING IN
THE COASTAL PLAIN IN THE AFTERNOON. LOW PROB OF A FEW
SHOWERS/TSTMS DEVELOPING IN W MA TOWARD EVENING.
WEDNESDAY NIGHT...MODERATE CONFIDENCE. AREAS OF IFR/LIFR STRATUS
AND PATCHY FOG LIKELY REDEVELOPING OVERNIGHT...ESPECIALLY NEAR THE
S COAST. PATCHY FOG ELSEWHERE. SCT SHOWERS/TSTMS POSSIBLE W MA
DURING THE EVENING WITH CHANCE OF SHOWERS/TSTMS ELSEWHERE
OVERNIGHT.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.
OUTLOOK /THURSDAY THROUGH SUNDAY/...
THURSDAY INTO FRIDAY...MODERATE CONFIDENCE.
A MIX OF LOW-END VFR TO IFR. IFR ESPECIALLY WITH +RA/TSRA FORECAST.
S FLOW BACKING N OVER TIME. IMPROVING INTO SATURDAY MORNING.
SATURDAY...MODERATE CONFIDENCE.
VFR. WINDS VEERING E/SE.
SUNDAY...LOW CONFIDENCE.
LOW-END VFR TO IFR WITH INCREASING CHANCES OF RAIN. E-WINDS INCREASE
THEN BACK W/NW WITH TIME.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH WEDNESDAY NIGHT/...HIGH CONFIDENCE.
730 PM UPDATE...NO MAJOR CHANGES TO THE FORECAST.
EXPECT SW FLOW THROUGH THE PERIOD...GUSTING TO 20 KT INTO EARLY
EVENING AND AGAIN DURING WEDNESDAY. A FEW HIGHER GUSTS TO 25 KT
POSSIBLE WED AFTERNOON/EVENING OVER NEARSHORE S COASTAL WATERS
AND A SCA MAY EVENTUALLY BE NEEDED. SEAS REMAIN BELOW 5 FT.
OUTLOOK /THURSDAY THROUGH SUNDAY/...
THURSDAY INTO FRIDAY...MODERATE CONFIDENCE.
LOW PRESSURE PASSING ACROSS S NEW ENGLAND SW TO NE THROUGH THE
PERIOD WITH RAIN. EMBEDDED HEAVIER SHOWERS AND THUNDERSTORMS
POSSIBLE. ENHANCING S-WINDS AHEAD OF THE LOW COULD GENERATE SEAS IN
EXCESS OF 5-FEET ON THE E-WATERS FOR THE LATE THURSDAY INTO FRIDAY
PERIOD. WILL SEE IMPROVEMENT INTO SATURDAY MORNING.
SATURDAY...MODERATE CONFIDENCE.
WINDS VEERING E/SE. GOOD BOATING WEATHER PREVAILS WITH SEAS BELOW 5-
FEET.
SUNDAY...LOW CONFIDENCE.
ANOTHER AREA OF LOW PRESSURE AND RAIN. TRACK UNCERTAIN. COULD SEE
IMPACTS ON THE WATERS THOUGH THEY MAY REMAIN MORE S AND E COMPARED
TO THURSDAY-FRIDAY.
&&
.CLIMATE...
RECORD HIGH TEMPERATURES FOR WEDNESDAY...9/9
BOS...91 IN 1971
PVD...91 IN 1971
ORH...90 IN 1915
BDL...91 IN 2002
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...AIR QUALITY ALERT UNTIL 11 PM EDT THIS EVENING FOR CTZ002.
MA...NONE.
RI...AIR QUALITY ALERT UNTIL 11 PM EDT THIS EVENING FOR RIZ001>008.
MARINE...NONE.
&&
$$
SYNOPSIS...KJC/SIPPRELL
NEAR TERM...KJC/SIPPRELL
SHORT TERM...KJC
LONG TERM...SIPPRELL
AVIATION...KJC/SIPPRELL
MARINE...KJC/SIPPRELL
CLIMATE...WFO BOX STAFF
AREA FORECAST DISCUSSION
NWS ALBANY NY
125 PM EDT MON SEP 7 2015
.SYNOPSIS...
THE HOT WEATHER WILL CONTINUE INTO THE MIDDLE OF THE
WEEK WITH INCREASING HUMIDITY LEVELS. HIGH PRESSURE OVER THE REGION
WILL SHIFT SOUTH AND EAST OVER THE NEXT FEW DAYS. IN THE
MEANTIME...A COLD FRONT WILL GRADUALLY APPROACH FROM THE GREAT LAKES
REGION WITH INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS LATER IN
THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 125 PM EDT...LABOR DAY HAS FEATURED LOTS OF SUNSHINE AND
ABOVE NORMAL TEMPS. HUMIDITY LEVELS ARE STARTING TO CREEP UP TOO
WITH SFC DEWPTS RISING IN THE TO LOWER TO M60S. MOST OF THE CLOUD
COVER HAS BEEN SOME CIRRUS AND FEW-SCT CUMULUS BY THE MTNS...AS
THE CONVECTIVE TEMP ON THE 12Z KALY SOUNDING WAS 91F. THERE IS NOT
A STRONG FORCING MECHANISM FOR ISOLD CONVECTION TODAY. THE BEST
SHOT FOR ANY DEVELOPMENT WOULD BE FROM A LAKE BREEZE OFF ERIE OR
ONTARIO. WE WILL CONTINUE WITH A DRY FCST FOR THE AFTERNOON INTO
THE EARLY EVENING WITH THE SFC HIGH OFF THE NEW ENGLAND
SEABOARD...AND EXTENDING SW INTO THE MID ATLANTIC CORRIDOR IN
CONTROL. THE LATEST HRRR TRENDS ALSO INDICATE A DRY AFTERNOON TOO.
HIGH TEMPS WILL BE 10 TO 15 DEGREES ABOVE NORMAL FOR DAY...WITH
80-85F READINGS FOR THE MTNS...AND U80S TO A FEW L90S IN THE
VALLEY AREAS. SOME RETOOLING OF THE T/TD/RH/APPARENT TEMPS WERE
DONE BASED ON OBSERVATIONS...AND CLOUD COVER BASED ON THE VISIBLE
SATELLITE TRENDS. THE WINDS WILL VARY FROM THE SE TO SW AT 5-15 MPH.
A WEAK COLD FRONT...OR SFC TROUGH WILL APPROACH FROM THE OVERNIGHT
PERIOD INTO TOMORROW.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
FOR TONIGHT EXPECT MILD AND MUGGY CONDITIONS WITH LOWS IN THE MID
60S TO AROUND 70. THE COLD FRONT WILL SLOWLY MOVE FROM THE CENTRAL
GREAT LAKES INTO THE EASTERN GREAT LAKES. IT WILL STILL BE MAINLY
DRY ACROSS THE FA WITH JUST A SLIGHT CHANCE TO LOW CHANCE OF
SHOWERS AND THUNDERSTORMS LATE AT NIGHT ACROSS FAR NORTHWEST
PORTIONS OF THE FA.
ON TUESDAY THE FRONTAL BOUNDARY WILL BE STALLED ACROSS THE EASTERN
GREAT LAKES...SOUTHERN ONTARIO AND SOUTHERN QUEBEC. WHILE MOST OF
THE FA WILL BE DRY EXPECT WIDELY SCATTERED TO SCATTERED SHOWERS
AND THUNDERSTORMS ACROSS THE NORTHERN HALF OF THE FA. ANY
THUNDERSTORM ACTIVITY WILL DIMINISH TUESDAY EVENING WITH ANOTHER
WARM AND MUGGY NIGHT. EXPECT HIGHS ON TUESDAY TO BE IN THE MID 80S
TO LOWER 90S WITH LOWS TUESDAY NIGHT IN THE MID TO UPPER 60S.
FOR WEDNESDAY AND WEDNESDAY NIGHT EXPECT AN INCREASING CHANCE OF
SHOWERS AND THUNDERSTORMS AS THE COLD FRONT MOVES FROM THE EASTERN
GREAT LAKES WEDNESDAY MORNING INTO EASTERN NEW YORK AND SOUTHERN
VERMONT LATE WEDNESDAY NIGHT. PWATS DURING THIS TIME INCREASE TO
1.75 TO 2+ INCHES...ML MUCAPES INCREASE TO 500 TO 1000 J/KG WITH
DEWPOINTS REMAINING MAINLY IN THE 60S. AT THIS TIME NOT EXPECTING
THE THUNDERSTORMS TO BE SEVERE. HOWEVER AS WE GET INTO WEDNESDAY
AND WEDNESDAY NIGHT HEAVY DOWNPOURS WILL BE POSSIBLE WITH ANY
THUNDERSTORMS ESPECIALLY GIVEN THE HIGH PWAT VALUES. HIGHS ON
WEDNESDAY ARE EXPECTED TO BE IN THE MID 80S TO AROUND 90 WITH LOWS
WEDNESDAY NIGHT IN THE MID TO UPPER 60S.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
A PATTERN CHANGE WILL BE UNDERWAY DURING THIS TIME PERIOD...AS THE
RECENT EASTERN NOAM RIDGE PUSHES FURTHER EAST OFF THE COAST...WHILE
AN UPPER LEVEL TROUGH ATTEMPTS TO DEVELOP ACROSS THE NORTHERN
PLAINS/UPPER GREAT LAKES REGION. MODELS EXHIBIT CONSIDERABLE
UNCERTAINTY AS TO HOW THIS PATTERN CHANGE UNFOLDS...WITH THE 00Z/07
GFS AND GEFS REMAINING MORE PROGRESSIVE WITH THE EVOLVING
PATTERN...WHILE THE 00Z/07 ECMWF IS SLOWER AND MUCH MORE AMPLIFIED.
THIS DIFFERENCE IS MOST NOTABLE FOR NEXT WEEKEND...AS THE GFS WOULD
IMPLY A QUICKER PASSAGE OF THE UPPER LEVEL TROUGH...ALONG WITH
SCATTERED RAIN SHOWERS FOR SAT...WHILE THE ECMWF WOULD IMPLY ENERGY
HOLDING BACK AND POTENTIALLY CARVING OUT A POSSIBLE CLOSED MID LEVEL
LOW CENTER WHICH COULD BRING A POSSIBLE WIDESPREAD STEADY RAINFALL
FOR NEXT SUNDAY...ALONG WITH MUCH BELOW NORMAL TEMPS. FOR NOW...HAVE
SIDED A BIT CLOSER TO THE GFS/GEFS SIDE FOR CONTINUITY...BUT TRENDS
WILL NEED TO BE WATCHED AS WE GET CLOSER TO NEXT WEEKEND.
HERE ARE SOME SPECIFICS...
THU-THU NT...MOST LONG TERM GUIDANCE SUGGEST THAT THE HIGHEST
PROBABILITY OF SHOWERS/THUNDERSTORMS WOULD BE DURING THIS TIME
PERIOD AS A POSSIBLE LEAD UPPER LEVEL IMPULSE AND ASSOCIATED COLD
FRONT SLOWLY MOVE ACROSS FROM THE WEST/NORTHWEST. THERE COULD BE
MULTIPLE WAVES OF LOW PRESSURE ALONG THIS FRONT AS IT MOVES THROUGH.
IT APPEARS THAT WIDESPREAD SHOWERS...ALONG WITH SOME EMBEDDED
THUNDERSTORMS WILL BE LIKELY THU...WITH SHOWERS PERSISTING INTO THU
NT. LOCALLY HEAVY RAINFALL COULD OCCUR...AS PWAT/S POTENTIALLY REACH
INTO THE 1.75-2 INCH RANGE. IT SHOULD BE HUMID...WITH MAX TEMPS HELD
DOWN TO TO CLOUDS AND SHOWERS...MAINLY IN THE UPPER 70S-LOWER 80S IN
VALLEYS...AND LOWER 70S ACROSS HIGHER TERRAIN. SLIGHTLY WARMER TEMPS
COULD OCCUR IN SOME LOWER ELEVATIONS SHOULD THE FRONT AND ASSOCIATED
CLOUDS/RAIN BE DELAYED. THU NT/FRI AM MINS SHOULD FALL INTO THE
LOWER/MID 60S FOR LOWER ELEVATIONS...AND 55-60 ACROSS HIGHER
ELEVATIONS.
FRI-SAT...SHOWERS MAY BE SLOW TO EXIT ON FRI...ESP FOR AREAS E OF
THE HUDSON RIVER...AS THE MID/UPPER LEVEL FLOW REMAINS SOMEWHAT
SOUTHWEST WITH THE RIDGE PERSISTING OFF THE EAST COAST. WILL
THEREFORE KEEP CHC POPS FOR MOST AREAS IN THE MORNING...THEN
DECREASE TO SLIGHT CHC FOR N/W AREAS IN THE AFTERNOON. WILL THEN
SIDE CLOSER TO THE GFS/GEFS FOR FRI NT-SAT...KEEPING SLIGHT CHC
SHOWERS FRI NT...AND MAINLY CHC POPS FOR SCATTERED SHOWERS SAT AS
THE MAIN UPPER TROUGH MOVES THROUGH. EXPECT COOLER TEMPS...WITH FRI
AND SAT MAX TEMPS IN THE 70S FOR VALLEYS...AND 60S ACROSS HIGHER
TERRAIN...ALTHOUGH SHOULD CLOUDS/SHOWERS LINGER ON FRI...EVEN COOLER
TEMPS COULD OCCUR. FRI NT/SAT AM MINS SHOULD FALL INTO THE MID 50S
TO LOWER 60S...WARMEST ACROSS THE MID HUDSON VALLEY AND NW CT.
SAT NT-SUN...THE 00Z/07 GFS WOULD IMPLY A RETURN TO FAIR
WEATHER...WHILE THE 00Z/07 ECMWF WOULD IMPLY CLOUDS AND RAIN
RETURNING DURING SUNDAY...ALONG WITH VERY COOL MAX TEMPS...POSSIBLY
ONLY REACHING THE 60S IN VALLEYS AND 50S ACROSS HIGHER TERRAIN.
AGAIN...HAVE SIDED CLOSER TO THE GFS/GEFS...HOLDING OFF MENTION OF
RAIN AT THIS TIME AND WITH WARMER TEMPS COMPARED TO THE ECMWF...WITH
MAX TEMPS REACHING THE 60S AND 70S. HOWEVER...AS MENTIONED
ABOVE...TRENDS WILL NEED TO BE WATCHED IN CASE UPPER LEVEL ENERGY
GETS HELD BACK AND THEN FORMS INTO AN UPPER LEVEL LOW AS SUGGESTED
BY THE ECMWF...WHICH WOULD IMPLY A MUCH MORE PESSIMISTIC FORECAST
FOR NEXT SUNDAY.
&&
.AVIATION /17Z MONDAY THROUGH FRIDAY/...
HIGH PRESSURE WILL SHIFT OFF THE MID ATLANTIC COAST THROUGH TONIGHT.
A WEAK COLD FRONT WILL APPROACH FROM THE NORTH LATE TUESDAY. ONLY A
FEW CU AND/OR HIGH LEVEL CIRRUS CLOUDS AROUND THIS AFTERNOON AND
EVENING.
FOR TONIGHT...THERE IS A POSSIBILITY OF PATCHY FOG FORMATION AND
MVFR/IFR CONDITIONS AT KPSF AFTER 05Z/TUE...AS SOME WIND MAY KEEP
THE BOUNDARY LAYER JUST MIXED ENOUGH TO PREVENT FOG FROM FORMING.
ELSEWHERE...ENOUGH OF A BREEZE SHOULD PREVENT MUCH FOG FROM
FORMING...WITH VFR CONDITIONS EXPECTED. AFTER 13Z-14Z...ANY FOG
SHOULD BURN OFF AND VFR CONDITIONS SHOULD PREVAIL THROUGH TUESDAY
MORNING.
SOUTH-SOUTHWEST WINDS THIS AFTERNOON AND EVENING AROUND 5-10 KTS.
WINDS WILL DECREASE TO LESS THAN 8 KT THIS EVENING AND CONTINUE
THROUGH THE NIGHT. SOUTH TO SOUTHWEST WINDS ARE EXPECTED AT LESS
THAN 10 KT TUESDAY MORNING.
OUTLOOK...
MON NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
TUE: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA...TSRA.
TUE NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
WED: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA...TSRA.
WED NIGHT-THU: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
THU NIGHT-FRI: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
&&
.FIRE WEATHER...
THE HOT WEATHER WILL CONTINUE INTO THE MIDDLE OF THE WEEK WITH
INCREASING HUMIDITY LEVELS. THE HIGH PRESSURE OVER THE REGION WILL
SHIFT SOUTH AND EAST OVER THE NEXT FEW DAYS. IN THE MEANTIME...A
COLD FRONT WILL GRADUALLY APPROACH FROM THE GREAT LAKES REGION.
RELATIVE HUMIDITIES WILL DROP TO 35 TO 55 PERCENT THIS
AFTERNOON...RECOVER TO 80 TO 100 PERCENT TONIGHT...AND DROP TO 35
TO 55 PERCENT TUESDAY AFTERNOON.
WINDS WILL BE SOUTHWEST TO WEST AT 5 TO 15 MPH TODAY...SOUTHWEST
AT 5 TO 10 MPH TONIGHT AND TUESDAY.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED THE NEXT FEW DAYS. THE RIDGE OF HIGH
PRESSURE OVER THE REGION WILL SHIFT SOUTH AND EAST OVER THE NEXT
FEW DAYS AS A COLD FRONT GRADUALLY APPROACHES FROM THE GREAT LAKES
REGION. MAINLY DRY WEATHER IS EXPECTED UNTIL WEDNESDAY. THE COLD
FRONT IS EXPECTED TO MOVE INTO THEN STALL ACROSS THE REGION LATE
IN THE WEEK BRINGING MUCH NEEDED RAINFALL TO THE AREA. GUIDANCE
INDICATES PWATS SHOULD RISE UP TO ABOUT 2 INCHES AHEAD OF THE
BOUNDARY SO HEAVY DOWNPOURS WOULD BE EXPECTED WITH SOME STORMS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...IAA/WASULA
NEAR TERM...WASULA
SHORT TERM...11
LONG TERM...KL
AVIATION...NAS
FIRE WEATHER...IAA/11
HYDROLOGY...IAA/11
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
331 PM EDT MON SEP 7 2015
.DISCUSSION...
CURRENTLY/TONIGHT...LATEST HRRR HAS HAD A GOOD HANDLE ON
CONVECTIVE DEVELOPMENT THIS AFT WITH SCT-NMRS SHOWER/STORM
COVERAGE NEAR THE TREASURE COAST/BREVARD COUNTY TOWARD THE NRN
INTERIOR/I-4 CORRIDOR. THIS FOCUS FOR STORMS HAS INITIATED FROM A
COMBINATION OF BOUNDARY COLLISIONS AND A MID LEVEL VORT MAX
CROSSING THE REGION. THIS CONVECTIVE ACTIVITY WILL CONTINUE TO
BUILD NORTHWARD WITH ADDITIONAL DEVELOPMENT POSSIBLE ACROSS THE
INTERIOR WHERE SOME BREAKS IN THE HIGHER CLOUD COVER ARE
OCCURRING. A FEW STRONGER STORMS WILL CONTINUE INTO LATE
AFT/SUNSET WITH FREQUENT LIGHTNING...STRONG WIND GUSTS AND LOCALLY
HEAVY RAINFALL POSSIBLE. SOME STORMS HAVE ALSO EXHIBITED ROTATION
THIS AFT THAT COULD PRODUCE ISOLATED FUNNEL CLOUDS.
MODELS INDICATE DECREASING CONVECTION INTO LATE EVENING AND HAVE
RAIN CHANCES ENDING BY MIDNIGHT. LOW LEVEL S/SW FLOW SHOULD KEEP
ANY CONVECTION THAT DEVELOPS OVER THE WATERS OFFSHORE OVERNIGHT.
LOWS EXPECTED IN THE LOW TO MID 70S.
TUE-WED...ABOVE NORMAL RAIN CHANCES CONTINUE TOMORROW AS A MOIST
AIRMASS REMAINS IN PLACE WITH LOW PRESSURE OVER THE EASTERN GULF
LIFTING SLOWLY NORTHWARD. POPS RANGE FROM 50 PERCENT OVER BREVARD
COUNTY/TREASURE COAST UP TO 60-70 PERCENT FARTHER INLAND WHERE
BOUNDARY COLLISIONS ARE MORE LIKELY. RAIN CHANCES THEN DECREASE
WED AS LOW OVER THE GULF RETROGRADES WEST AND DEEPER RIDGE BUILDS
IN FROM THE EAST. DRY MID LEVEL AIR WILL BE DRAWN IN FROM THE
SOUTH-SOUTHWEST WITH LATEST ANALYSIS SHOWING 850-500MB MEAN RH
VALUES AOB 40PCT. WILL KEEP POPS RANGING FROM 20 PERCENT OVER THE
FAR SOUTH TO 30-40 PERCENT NORTH OF OKEECHOBEE COUNTY AND SRN
TREASURE COAST. HIGHS WILL INCREASE FROM UPPER 80S TO AROUND 90
DEG TUE TO LOW 90S OVER MUCH OF THE AREA WED.
THU-SUN...(PREVIOUS DISCUSSION) H30-H20 JET PATTERN EXPECTED TO
AMPLIFY THRU THE LATTER HALF OF THE WEEK AS A 120KT ZONAL JET BTWN
THE ALEUTIANS ISLANDS AND THE KAMCHATKA PENINSULA WORKS ITS WAY
INTO THE PAC NW. THIS WILL ALLOW A WEAK FRONTAL BOUNDARY EXTENDING
FROM THE UPR MID WEST TO THE CENTRAL PLAINS TO DEEP AS IT DRIFTS
INTO THE ERN CONUS.
THE POSITIVE ORIENTATION OF THE TROF AND THE FACT THAT MOST OF THE
JET ENERGY WILL REMAIN WELL N OF THE CANADIAN BORDER SUGGESTS IT
WILL NOT BE ABLE TO UPROOT THE ATLC RIDGE FROM ITS POSITION OVER THE
FL PENINSULA. HOWEVER...IT WILL KEEP ITS AXIS SUPPRESS OVER THE SRN
HALF OF THE PENINSULA...RESULTING INT A DEEP S/SW FLOW PATTERN THRU
THE COLUMN. FCST WILL HAVE HIGHER COASTAL POPS TO REFLECT THIS...
THOUGH AREAS DOWNWIND OF LAKE OKEECHOBEE MAY SEE DIMINISHED POPS
DUE TO THE SHADOW EFFECT. LITTLE CHANGE IN DAY-TO-DAY MAX/MIN TEMPS
AS THE S/SWRLY FLOW KEEPS CENTRAL FL UNDER A SULTRY TROPICAL
AIRMASS.
&&
.AVIATION...TEMPO IFR/MVFR CONDS WITH GREATER COVERAGE OF SHOWERS
AND STORMS NEAR THE BREVARD/TREASURE COASTS AND NRN INTERIOR/I-4
CORRIDOR. STORMS WILL GENERALLY MOVE N/NE BUT NW MOTION ALSO
POSSIBLE NORTH OF ORLANDO. SOME THINNING/BREAKS IN THE HIGHER
CLOUD COVER OVER THE INTERIOR MAY INITIATE ADDITIONAL SCT
SHRA/TSRA THROUGH LATE AFT/SUNSET. DECREASING COVERAGE THEN
EXPECTED INTO THE EVENING WITH VFR CONDS RETURNING FOR THE
OVERNIGHT PERIOD.
&&
.MARINE...
TONIGHT...SE WINDS INCREASE UP TO 10-15 KNOTS OVER THE
WATERS...EAST OF WEAK LOW OVER THE EASTERN GULF. SEAS EXPECTED TO
INCREASE ONLY SLIGHTLY TO 2-3 FEET. MAIN CONCERN WILL CONTINUE TO
BE ANY OFFSHORE MOVING STORMS WITH GUSTY WINDS ALONG THE COAST
THROUGH LATE AFT/SUNSET AND SCATTERED STORMS THAT CAN REDEVELOP
AND MOVE NORTHWARD OVER THE WATERS OVERNIGHT.
TUE-WED...FAVORABLE BOATING CONDITIONS AS THE ATLC RIDGE AXIS
REBUILDS ITSELF OVER THE LCL ATLC IN THE WAKE OF THE DEPARTING LOW
PRES SYSTEM CURRENTLY OVER THE ERN GOMEX. AXIS POSITIONED OVER THE
TREASURE COAST/NRN BAHAMAS SUGGESTS A LIGHT TO GENTLE SRLY FLOW THRU
MIDWEEK...BCMG E/SE NEAR THE COAST IN THE AFTN AS THE EAST COAST SEA
BREEZE DVLPS. SEAS AOB 2FT NEARSHORE AND 2-3FT OFFSHORE.
THU-FRI...A FRONTAL TROF OVER THE UPR MIDWEST/CENTRAL PLAINS WILL
DRIFT INTO THE ERN CONUS ON THU THEN OFF THE ERN SEABOARD ON FRI.
THIS WILL DISPLACE THE ATLC RIDGE TO THE VCNTY OF LAKE OKEECHOBEE...
FORCING SFC/BNDRY LYR WINDS TO VEER TO THE S/SW...GENERALLY AOB
10KTS. SEAS 2FT NEARSHORE AND 2-3FT OFFSHORE THRU THE DAY THU...BCMG
AOB 2FT AREAWIDE ON FRI
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 75 89 75 91 / 40 60 40 40
MCO 74 89 75 92 / 40 60 30 40
MLB 75 90 76 92 / 40 50 30 30
VRB 74 90 75 91 / 40 50 30 30
LEE 75 89 76 92 / 40 60 20 40
SFB 74 90 76 92 / 40 60 30 40
ORL 75 89 76 92 / 40 60 30 40
FPR 75 91 75 92 / 40 50 30 20
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
FORECASTS...WEITLICH
RADAR/IMPACT WX/AVIATION...KELLY
AREA FORECAST DISCUSSION
NWS MIAMI FL
307 PM EDT MON SEP 7 2015
.SHORT TERM (TONIGHT-WEDNESDAY NIGHT)...
A MID LEVEL TROUGH IS CURRENTLY CENTERED OVER THE NORTHEAST GULF
OF MEXICO WITH A SURFACE TROUGH EXTENDING FROM NEAR JAX INTO THE
SOUTHEAST GULF. THIS IS PROVIDING A DEEP SOUTH-SOUTHWEST FLOW OF
TROPICAL AIR INTO SOUTH FLORIDA WITH PWAT JUST OVER 2". THIS ALSO
SET THE STAGE FOR EARLY MORNING THUNDERSTORMS MOVING ONSHORE OF
THE SOUTHWEST COAST EXPANDING ACROSS THE REMAINDER OF THE
PENINSULA INTO EARLY THIS AFTERNOON. AS A RESULT, THE AIRMASS IS
STABILIZING OVER THE LAND AREAS AND HAVE THUS REDUCED THE POPS
SIGNIFICANTLY MOST AREAS. DUE TO THE PROXIMITY OF THE LOW AND COOL
TEMPERATURES ALOFT, CANNOT RULE OUT SOME CONVECTIVE ACTIVITY
THROUGH THE NIGHT ALTHOUGH THE HRRR IS NOT SHOWING MUCH AT ALL.
BOTH THE GFS AND ECMWF SHOW THE LOW SHIFTING TO THE NORTHWEST ON
TUESDAY WITH SOME WARMING AT 500MB AS THE ATLANTIC RIDGE ALSO
SHIFTS BACK TO THE WEST. HOWEVER, AS THIS PATTERN ENFOLDS THE LOW
LEVELS WILL DESTABILIZE WITH INCREASED DIURNAL HEATING BOTH
TUESDAY AND WEDNESDAY. THE FLOW WILL ALSO BACK TO A MORE SOUTH-
SOUTHEAST DIRECTION SO A CONTINUATION OF THE TROPICAL FLOW OF AIR
AND PWAT REMAINING NEAR 2" SO THE CHANCES OF RAIN WILL BE
ELEVATED. THE BACKING STEERING FLOW WILL REVERT THE HIGHEST POPS
FROM THE EAST METRO AREA TO MOSTLY THE INTERIOR SO THE GRIDS WILL
REFLECT THIS PATTERN SHIFT.
.LONG TERM (THURSDAY-MONDAY)...
A DEEP LAYER RIDGE WILL BE THE MAIN INFLUENCE ON SOUTH FLORIDA ON
THURSDAY AND FRIDAY SO MOSTLY SEA BREEZE INTERACTION TYPE
THUNDERSTORM ACTIVITY WILL BE THE PRIMARY PATTERN. OVER THE
WEEKEND AND INTO EARLY NEXT WEEK, THE DIURNAL CYCLE WILL LIKELY
CONTINUE WITH PWAT HOVERING CLOSE TO OR JUST UNDER 2" BUT THE
PATTERN IS A LITTLE UNCERTAIN. BOTH THE GFS AND ECMWF SHOW AN
UPSTREAM MID LEVEL TROUGH WEAKENING THE RIDGE ACROSS SOUTH FLORIDA
BUT THE ECMWF SHOWS A BROADER TROUGH WITH A DEEP SOUTHWESTERLY
FLOW RETURNING. THE GFS ON THE OTHER HAND SHOWS A MORE CLOSED LOW
CIRCULATION AND FARTHER TO OUR NORTH KEEPING THE FLOW MOSTLY
EASTERLY. FOR NOW, WILL SHOW THE HIGHEST POPS OVER THE INTERIOR
AREAS.
&&
.MARINE...
A SOUTH TO SOUTHEAST WIND IS EXPECTED THROUGH THE FORECAST PERIOD
WITH SEAS OF GENERALLY LESS THAN 4 FEET OUTSIDE OF STRONGER
SHOWERS AND THUNDERSTORMS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 78 92 79 92 / 20 40 20 40
FORT LAUDERDALE 79 91 81 91 / 20 40 10 30
MIAMI 78 91 80 92 / 20 40 10 30
NAPLES 77 91 77 91 / 30 50 10 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...30/KOB
LONG TERM....30/KOB
AREA FORECAST DISCUSSION
NWS MIAMI FL
142 PM EDT MON SEP 7 2015
.AVIATION...
CONVECTION IS SLOWING DOWN THIS AFTERNOON. THIS IS IN AGREEMENT
WITH THE SHORT RANGE HRRR MODEL. THERE IS A POTENTIAL FOR
ADDITIONAL CONVECTION THIS AFTERNOON, SO, HAVE A TEMPO FOR A
COUPLE HOURS LONGER, AND VCTS FOR MOST OF THE AFTERNOON, ALTHOUGH
BACKED UP THE CUTOFF TIME BY AN HOUR. DUE TO THE CONVECTION, THE
WINDS HAVE BEEN ERRATIC, AND MAY CONTINUE TO BE SO UNTIL AFTER ALL
THE CONVECTION WINDS DOWN. OTHERWISE, MAINLY VFR CONDITIONS ACROSS
SOUTH FLORIDA, EXCEPT UNDER HEAVY SHOWERS AND THUNDERSTORMS.
&&
.PREV DISCUSSION... /ISSUED 858 AM EDT MON SEP 7 2015/
UPDATE...
LATEST UPDATE CONTAINS MINOR TWEAKS TO MAINLY THE WIND AND SKY
ELEMENTS. THERE ARE SOME LARGER ADJUSTMENTS TO THE POPS ALONG THE
GULF COAST, WHERE A LINE OF SHOWERS AND THUNDERSTORMS ARE MOVING
ONSHORE.
AVIATION...
WITH A WEAK LOW, CENTERED JUST TO THE NORTHWEST, THE FLOW WILL
CONTINUE TO BE SOUTH TO SOUTHEASTERLY. THIS SHOULD HELP TO PUSH
SOME OF THE SHOWERS AND THUNDERSTORMS A LITTLE FURTHER INLAND THAN
YESTERDAY. HOWEVER, THERE IS STILL A CHANCE THEY CAN IMPACT THE
TAF SITES, MAINLY IN THE AFTERNOON HOURS. VFR WILL BE THE
PREDOMINATE FORECAST, HOWEVER, BRIEF IFR IS POSSIBLE UNDER HEAVY
SHOWERS AND THUNDERSTORMS.
PREV DISCUSSION... /ISSUED 316 AM EDT MON SEP 7 2015/
.LATE SUMMER TIME WEATHER PATTERN SETTING UP OVER SOUTH FLORIDA
THIS WEEK...
SHORT TERM...
A MID TO UPPER LEVEL LOW OVER THE NORTHEAST GULF OF MEXICO WILL
MOVE SLOWLY WEST INTO THE NORTHERN CENTRAL GULF OF MEXICO
TODAY...AS HIGH PRESSURE REMAINS OVER THE WESTERN ATLANTIC WATERS.
THIS WILL KEEP A SOUTHERLY WIND FLOW OVER SOUTH FLORIDA TODAY
FOCUSING THE SHOWERS AND THUNDERSTORMS OVER THE NORTHERN AREAS.
HOWEVER...ALL OF SOUTH FLORIDA WILL SEE AT LEAST SCATTERED POPS
TODAY.
THE MID TO UPPER LEVEL LOW WILL CONTINUE TO RETROGRADE WESTWARD
WHILE WEAKENING INTO THE WESTERN GULF OF MEXICO INTO WEDNESDAY...AS
HIGH PRESSURE OVER THE WESTERN ATLANTIC WATERS BUILDS WESTWARD
INTO THE FLORIDA PENINSULA. THIS WILL ALLOW FOR THE WIND FLOW TO
BECOME EASTERLY OVER SOUTH FLORIDA AND BRING IN SOME DRIER AIR TO
THE AREA. THEREFORE...THE HIGHEST POPS WILL SHIFT TO THE WESTERN
AREAS OF SOUTH FLORIDA FOR THE MIDDLE PART OF THE WEEK.
LONG TERM...
THE HIGH WILL REMAIN OVER THE FLORIDA PENINSULA LATE THIS WEEK AND
INTO NEXT WEEKEND...KEEPING THE EASTERLY WIND FLOW OVER SOUTH
FLORIDA. THIS WILL KEEP THE HIGHEST POPS OVER THE WESTERN AREAS OF
SOUTH FLORIDA WITH ONLY ISOLATED TO LOW END SCATTERED POPS OVER
THE EASTERN AREAS OF SOUTH FLORIDA.
AVIATION...
THE WINDS WILL BE SOUTHERLY LESS THAN 5 KNOTS THIS MORNING OVER
THE EAST COAST TAF SITES...BEFORE SWINGING TO A SOUTH SOUTHEAST
DIRECTION AT 5 TO 10 KNOTS THIS AFTERNOON. FOR KAPF TAF SITE...THE
WINDS WILL BE LIGHT AND VARIABLE EARLY THIS MORNING BEFORE
BECOMING WESTERLY AT 5 TO 10 KNOTS THIS MORNING INTO THIS
AFTERNOON. SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE OVER ALL OF
THE TAF SITES AFTER 16Z TODAY. THEREFORE...VCTS WILL REMAIN IN ALL
OF SOUTH FLORIDA TAF SITES FOR THIS AFTERNOON. THE CEILING AND VIS
WILL REMAIN IN THE VFR CONDITIONS AT THIS TIME...DUE TO THE
UNKNOWN TIMING OF THE SHOWERS AND THUNDERSTORMS AFFECTING THE TAF
SITES. HOWEVER...THE CEILING AND VIS SHOULD FALL INTO THE MVFR OR
EVEN IFR CONDITIONS WHEN A SHOWER OR THUNDERSTORM MOVES OVER THE
TAF SITE.
MARINE...
THE WINDS WILL BE SOUTHERLY AT 5 TO 10 KNOTS TODAY BEFORE BACKING
TO AN EAST TO SOUTHEAST DIRECTION TONIGHT THROUGH THE REST OF
THIS WEEK. THIS WILL KEEP THE SEAS AT 2 FEET OR LESS IN BOTH THE
ATLANTIC AND GULF WATERS OF SOUTH FLORIDA THROUGH THIS WEEK.
THEREFORE...BOATING CONDITIONS SHOULD BE GOOD OUTSIDE OF ANY
SHOWERS OR THUNDERSTORMS THIS WEEK OVER SOUTH FLORIDA WATERS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 78 92 79 92 / 40 40 20 20
FORT LAUDERDALE 80 91 81 91 / 30 30 20 20
MIAMI 79 92 80 92 / 20 40 20 20
NAPLES 77 91 77 91 / 20 30 20 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...13/SI
LONG TERM....54/BNB
AVIATION...13/SI
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
801 PM EDT TUE SEP 8 2015
.SYNOPSIS...
HIGH PRESSURE IN THE ATLANTIC WILL CIRCULATE A MOIST SOUTH FLOW
INTO THE FORECAST AREA THROUGH THURSDAY. A WEAK SURFACE TROUGH
WILL ALSO BE NEAR THE AREA. THE PATTERN WILL SUPPORT A CONTINUED
CHANCE OF SHOWERS AND THUNDERSTORMS ESPECIALLY NEAR THE TIMES OF
MAXIMUM HEATING. DRIER AIR WILL BEGIN TO FILTER INTO THE REGION BY
THE BEGINNING OF NEXT WEEK BEHIND A COLD FRONT THAT WILL PUSH
THROUGH OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AIR MASS WEAKLY UNSTABLE THIS EVENING. SHOWERS AND THUNDERSTORMS
ISOLATED. LATEST RADAR AND SATELLITE TRENDS SUGGEST WEAKENING
TREND. HRRR IN AGREEMENT. WILL CUT POPS BACK. STRATUS EXPECTED
LATE TONIGHT. PATCHY FOG ALSO POSSIBLE.
LEANED TOWARD THE WARMER LOW TEMPERATURE GUIDANCE BECAUSE OF THE
DEEP MOISTURE WITH LOWS IN THE LOWER 70S.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
MODELS REMAIN IN GOOD AGREEMENT THROUGH THIS TIME PERIOD. UPPER
PATTERN WILL BE OUT OF THE SOUTHWEST...WITH THE MAIN UPPER TROUGH
STILL OFF TO THE WEST OF THE REGION. CENTER OF THE UPPER RIDGE
WILL BE OVER SOUTHERN FLORIDA. WITH GOOD SOUTH TO SOUTHWESTERLY
LOW-LEVEL FLOW EXPECTED TO OCCUR THROUGH THE PERIOD...MOISTURE IS
EXPECTED TO CONTINUE TO INCREASE EACH DAY ACROSS THE REGION.
AFTERNOON TEMPERATURES WILL CONTINUE TO BE IN THE LOWER 90S FOR
MOST AREAS...WITH OVERNIGHT LOWS FALLING INTO THE LOWER 70S. WITH
THE MOISTURE INCREASE EXPECT TO SEE SCATTERED SHOWERS AND
THUNDERSTORMS TO DEVELOP EACH AFTERNOON DURING THE TIME OF MAXIMUM
HEATING.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS WITH PREVIOUS DAYS FORECAST RUNS...THE GFS/ECMWF BEGIN TO
DIVERGE WITH THEIR SOLUTIONS THROUGH THE LONGER TERM. BOTH MODELS
DIVE AN UPPER TROUGH SOUTHEASTWARD OUT OF THE UPPER PLAINS STATES
FRIDAY NIGHT INTO SATURDAY...THEN CREATE A CUTOFF LOW ACROSS THE
EASTERN US. ITS THE DEVELOPMENT AND PLACEMENT OF THIS CUTOFF THAT
THE MODELS DISAGREE WITH OVER THE WEEKEND. THE GFS IS FURTHER
SOUTH AND WEAKER THAN THE ECMWF...WITH THE ECMWF LIFTING THE LOW
QUICKER TOWARDS THE NORTHEAST SUNDAY INTO MONDAY. OBVIOUSLY THE
PLACEMENT AND MOVEMENT OF THE UPPER LOW WILL EVENTUALLY HAVE AN
AFFECT ON THE FINAL PLACEMENT AND MOVEMENT OF THE EXPECTED COLD
FRONT THAT WILL MOVE THROUGH THE REGION THIS WEEKEND.
BOTH MODELS HAVE A PREFRONTAL TROUGH ACROSS THE REGION THROUGH
SATURDAY. WHATEVER THE FINAL TRACK IS FOR THE UPPER LOW...BOTH
MODELS SHOW THE FRONT PUSHING TOWARDS THE COAST ON SUNDAY...WITH
THE ECMWF BEING FASTER WITH THE TRACK. HAVE LEANED A LITTLE MORE
TOWARDS A BLEND OF THE TWO MODELS FOR NOW. EXPECTING SHOWERS AND
THUNDERSTORMS TO OCCUR EACH AFTERNOON THROUGH SUNDAY...WITH DRYING
FINALLY BEGINNING TO PUSH IN SUNDAY NIGHT.
THE REGION SHOULD BEGIN TO SEE SOME COOLER TEMPERATURES AND DRYING
TO START OFF THE WORK WEEK BEHIND THE COLD FRONTAL PASSAGE.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
ISOLATED SHOWERS CONTINUE ACROSS THE FORECAST AREA THIS EVENING BUT
CURRENT RADAR TRENDS SHOW NO THREAT AT THE TERMINALS. HIGH
RESOLUTION MODELS ALL INDICATING IFR/MVFR CONDITIONS DEVELOPING LATE
TONIGHT. THIS AGREES WITH PERSISTENCE...SO WILL INCLUDE MORNING
STRATUS AND/OR FOG IN ALL TAF SITES ON WEDNESDAY. COULD SEE ISOLATED
SHOWERS OVERNIGHT GIVEN WEAK ISENTROPIC LIFT. CONDITIONS EXPECTED TO
IMPROVE TO VFR AROUND MIDDAY WEDNESDAY AS SOUTHWEST WINDS INCREASE
TO AROUND 5 TO 10 KNOTS. SCATTERED CONVECTION WILL RECONVENE DURING
THE AFTERNOON ONCE AGAIN.
. EXTENDED AVIATION OUTLOOK...LATE NIGHT/MORNING FOG/STRATUS
POSSIBLE...WITH A CHANCE OF AFTERNOON SHOWERS AND POSSIBLE
THUNDERSTORMS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
99
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
651 PM EDT MON SEP 7 2015
.SYNOPSIS...
AN INLAND WEDGE OF HIGH PRESSURE AND A COASTAL TROUGH WILL DISSIPATE
TUESDAY AND TUESDAY NIGHT. ATLANTIC HIGH PRESSURE WILL THEN BUILD
OVER THE SOUTHEAST UNTIL A COLD FRONT APPROACHES THE REGION LATE
THIS WEEK. THE COLD FRONT WILL STALL OVER OR CLOSE TO THE AREA NEXT
WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
DIURNAL CONVECTION WILL DIMINISH THROUGH THE EVENING WITH THE
LOSS OF HEATING. THROUGH THE OVERNIGHT...THE FORECAST AREA WILL
REMAIN ON THE EASTERN PERIPHERY OF A UPPER LOW SITUATED ALONG THE
GULF COAST. LATE IN THE NIGHT...DIFLUENCE WILL INCREASE AND THE
MODELS SHOW A NOTABLE SHORTWAVE MOVING INTO THE AREA FROM THE
SOUTH. AS THE FORCING ALOFT INCREASES...THE MODELS DEPICT A WARM
FRONT LIKE FEATURE LIFTING NORTHWARD WITH INCREASING SHOWER AND
THUNDERSTORM DEVELOPMENT ACCOMPANYING IT. THE MODEL PRECIPITATION
RESPONSE IS PRETTY CONSISTENT AMONGST THE SUITE OF MODELS AND
LENDS CONFIDENCE TO BRINGING IN INCREASING POPS FROM LATE EVENING
ON...MAINLY AT THE COAST AND AREAS SOUTH OF I-16 WHERE SURFACE
MOISTURE FLUX CONVERGENCE WILL BE THE MOST INTENSE. POPS WILL
RANGE FROM 10-20 PERCENT ACROSS THE FAR NORTHWESTERN TIER TO 50-60
PERCENT ALONG PARTS OF THE GEORGIA COAST. A MENTION OF HEAVY RAIN
HAS BEEN ADDED TO THE MOST OF THE GEORGIA COASTAL ZONES GIVEN THE
EXPECTED EFFICIENT RAINFALL RATES WITHIN THE VERY TROPICAL LIKE
ATMOSPHERE.
LOWS WILL BE QUITE SIMILAR TO LAST NIGHT...MAINLY IN THE 70-73
DEGREE RANGE AWAY FROM THE BEACHES. ANOTHER ROUND OF STRATUS
DEVELOPMENT IS EXPECTED TONIGHT AS WELL...AND THERE COULD BE SOME
AREAS THAT SEE LIGHT FOG DEVELOPMENT.
FOR THE EARLY EVENING UPDATE...MADE MINOR ADJUSTMENTS TO HOURLY
POPS TO MATCH GOING KCLX RADAR TRENDS AND TO SPEED UP THE
INTRODUCTION OF LIKELY POPS ACROSS THE FAR SOUTHERN COASTAL ZONES
PER RAP/H3R MODEL OUTPUT.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
THE INLAND WEDGE/COASTAL TROUGH WILL GRADUALLY WEAKEN TUESDAY.
BETWEEN AN UPPER LOW CENTERED WEST OF THE REGION AND AN UPPER RIDGE
BUILDING FROM THE SOUTHEAST...STRENGTHENING/MOIST SOUTHERLY FLOW
WILL CONVERGE/BE FORCED ALOFT BY SURFACE FEATURES OVER THE FORECAST
AREA...AND A WEAK WARM FRONT WILL ADVANCE NORTH THROUGH THE FORECAST
AREA. THIS SCENARIO SHOULD SUPPORT YET ANOTHER WET MORNING ALONG THE
COAST...ESPECIALLY ACROSS CENTRAL/SOUTHERN COASTAL COUNTIES. LIKELY
POPS ARE IN ORDER FOR THESE AREAS TUESDAY MORNING...TAPERED TO
SLIGHT CHANCE/CHANCE FARTHER NORTH/WEST. ALSO...PWATS EXCEEDING 2
INCHES WILL SUPPORT A THREAT FOR LOCALLY HEAVY RAIN. TUESDAY
AFTERNOON...PRECIPITATION COVERAGE BECOMES MORE UNCERTAIN AS THE
INLAND WEDGE/COASTAL TROUGH BECOME ILL-DEFINED...AND THE FOCUS FOR
CONVECTION SHIFTS TO THE SEA BREEZE/CONVECTIVE OUTFLOW BOUNDARIES.
CAPPED MAXIMUM AFTERNOON POPS AT AROUND 50 PERCENT...ESPECIALLY
ACROSS NORTHERN/INLAND COUNTIES...BUT LOCALLY GREATER AMOUNTS COULD
EVENTUALLY BE REQUIRED AS SHORT/NEAR TERM CONVECTIVE TRENDS COME
INTO FOCUS. CLOUDS/PRECIPITATION SHOULD LIMIT INSTABILITY...AND THE
POTENTIAL FOR SEVERE WEATHER REMAINS VERY LOW TUESDAY.
OTHERWISE...HIGH TEMPERATURES IN THE MID/UPPER 80S APPEAR
REASONABLE...HIGHEST SOUTH WHERE PRECIPITATION COVERAGE COULD WANE
DURING THE TIME OF MAX HEATING...ALTHOUGH TEMPERATURES COULD
STRUGGLE TO EXCEED TO THE LOWER 80S IF/WHERE CLOUDS/SHOWERS PERSIST.
TUESDAY NIGHT...POPS OVER LAND SHOULD DIMINISH..AND THE FOCUS FOR
ISOLATED/SCATTERED SHOWERS/THUNDERSTORMS SHOULD SHIFT TO COASTAL
COUNTIES ADJACENT COASTAL WATERS WHERE LOW LEVEL MASS/MOISTURE
CONVERGENCE IS EXPECTED TO DEVELOP. LOW WILL RANGE FROM THE
LOWER/MID 70S INLAND TO THE MID/UPPER 70S AT THE COAST.
WEDNESDAY...HIGH PRESSURE WILL BUILD INTO THE REGION AT THE SURFACE
AND ALOFT. SOUTH/SOUTHWEST FLOW ALOFT BETWEEN THE TROUGH TO THE WEST
AND HIGH PRESSURE CENTERED TO THE EAST/NORTHEAST WILL MAINTAIN A
FLOW OF TROPICAL MOISTURE FEATURING PWATS AROUND 2 INCHES ACROSS THE
REGION. THUS...AT LEAST CHANCE POPS FOR SCATTERED SHOWERS/
THUNDERSTORMS ARE IN ORDER ACROSS THE REGION...ESPECIALLY DURING THE
AFTERNOON AS THE SEA BREEZE ADVANCES INLAND. WHILE ELEVATED PWATS
WILL CONTINUE TO SUPPORT A LOCALIZED THREAT FOR HEAVY
RAIN...STRONGER INSTABILITY AS COMPARED WITH THE PAST FEW DAYS AND 0-
6 KM BULK SHEAR INCREASING TO 15-25 KT SUGGESTS SOME POTENTIAL FOR
MULTICELL CLUSTERS OF THUNDERSTORMS ACCOMPANIED BY A LOW CHANCE FOR
PULSE SEVERE THUNDERSTORMS WITH DAMAGING WIND GUSTS WEDNESDAY
AFTERNOON. MEANWHILE...OUTSIDE ANY THUNDERSTORMS HIGH TEMPERATURES
IN THE UPPER 80S/LOWER 90S SHOULD BECOME COMMON AWAY FROM THE COAST.
WEDNESDAY NIGHT...THE FOCUS FOR ISOLATED/SCATTERED SHOWERS/
THUNDERSTORMS SHOULD ONCE AGAIN SHIFT FROM INLAND COUNTIES TO
COASTAL COUNTIES/ADJACENT COASTAL WATERS. DUE TO UNCERTAINTY
REGARDING THE COVERAGE/IMPACTS OF WEDNESDAY AFTERNOON THUNDERSTORMS
FORECAST LOW TEMPERATURES AGAIN RANGE FROM THE LOWER/MID 70S INLAND
TO THE MID/UPPER 70S AT THE COAST. HOWEVER...A TIGHTENING PRESSURE
GRADIENT AND PERSISTENT WEST/SOUTHWEST WINDS AHEAD OF DEVELOPING PRE-
FRONTAL TROUGH NORTH OF THE REGION COULD HOLD TEMPERATURES IN THE
75-80F RANGE AT LOCATIONS WHERE NO RAIN OCCURS.
THURSDAY...07/12Z MODEL TRENDS SUGGESTS THAT THE REGION WILL REMAIN
POSITIONED BETWEEN ATLANTIC HIGH PRESSURE AND A LEE SIDE TROUGH
NORTH/WEST OF THE FORECAST AREA. THE RESULTING WEST/SOUTHWEST WINDS
AND COMPRESSIONAL HEATING SHOULD SUPPORT ABOVE NORMAL HIGH
TEMPERATURES AT LEAST IN THE LOWER/MID 90S...AND 90F TEMPS COULD
EVEN BE PUSHED TO THE COAST BEFORE THE SEA BREEZE DEVELOPS. MAX HEAT
INDEX VALUES IN THE UPPER 90S/LOWER 100S COULD BE REALIZED THURSDAY
AFTERNOON. ALSO...ISOLATED/SCATTERED THUNDERSTORMS COULD DEVELOP
NEAR THE SEA BREEZE WHICH WILL STRUGGLE TO PUSH INLAND...AND
CLUSTERS OF CONVECTION UPSTREAM COULD PUSH INTO THE REGION
ESPECIALLY INLAND COUNTIES ESPECIALLY LATE. HOWEVER...A SUBTLE
DRYING TREND COULD TRANSLATE TO FEW/NO DIURNAL SHOWERS/
THUNDERSTORMS. MAINTAINED CHANCE POPS INLAND AND SLIGHT CHANCE POPS
ELSEWHERE...ESPECIALLY THURSDAY AFTERNOON...BUT COVERAGE OF
CONVECTION COULD REMAIN SPARSE THURSDAY PM.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
A FAIRLY PROGRESSIVE UPPER PATTERN LATE WEEK THROUGH THE WEEKEND
WILL PUSH A COLD FRONT INTO THE AREA LATE FRIDAY OR SATURDAY. THIS
FRONT IS EXPECTED TO STALL ACROSS SOUTHERN AREAS THROUGH THE
WEEKEND. THE PRIMARY IMPACT WILL BE A SLIGHT INCREASE IN SHOWER AND
TSTM COVERAGE ESPECIALLY ACROSS THE COASTAL WATERS AND SOUTHEAST GA
THOUGH ALL AREAS WILL SEE SOME CONVECTION. DECREASING THICKNESSES
AND GREATER SKY COVER WILL MAINTAIN HIGH TEMPS IN THE UPPER 80S.
&&
.AVIATION /22Z MONDAY THROUGH SATURDAY/...
KCHS...VFR FOR MUCH OF THE PERIOD. MODELS SUGGEST ANY LOW CLOUDS
SHOULD REMAIN WEST OF THE TERMINAL AS THE LOW-LEVEL FLOW VEERS
SOUTHEAST WITH TIME. THERE ARE SIGNALS THAT A BAND OF RAIN COULD
APPROACH THE TERMINAL FROM THE SOUTH BY 14-16Z TUESDAY...BUT
CONFIDENCE IN THIS SCENARIO PANNING OUT THIS FAR OUT IS TOO LOW
TO JUSTIFY A MENTION ATTM.
KSAV...VFR THIS EVENING WITH INCREASING PROBABILITIES FOR MVFR
CIGS/VSBYS AFTER 06Z. MODELS ARE SIMILAR IN SHOWING A LARGE AREA
OF RAIN DEVELOPING ALONG THE NORTHEAST FLORIDA AND FAR SOUTHERN
GEORGIA COAST LATER THIS EVENING...THEN TREKKING NORTH AND
POTENTIALLY IMPACTING THE TERMINAL ROUGHLY 08-11Z. GIVEN THE
SIMILARITIES NOTED IN BOTH THE H3R AND RAP MODELS...WILL GO AHEAD
AND INTRODUCE A TEMPO GROUP DURING THIS TIME FOR 4SM -RA. EXPECT
PREVAILING MVFR CIGS TO DEVELOP BY 07Z AHEAD OF THE RAIN WHICH
WILL LINGER INTO MID-MORNING TUESDAY BEFORE BREAKING OUT. THE
LATEST DATA SUGGEST CIGS WILL REMAIN ABOVE IFR THRESHOLDS...BUT
VSBYS COULD BRIEFLY DROP TO IFR THRESHOLDS IN POCKETS OF HEAVIER
RAINFALL. WILL NO INCLUDE ANY IFR CONDITIONS ATTM.
EXTENDED AVIATION OUTLOOK...OUTSIDE ANY SHOWERS/THUNDERSTORMS VFR
WILL PREVAIL MUCH OF THE TIME.
&&
.MARINE...
TONIGHT...THE PERSISTENT COASTAL TROUGH IS EXPECTED TO BE ALIGNED
RIGHT AT THE COAST THIS EVENING AND THEN GRADUALLY DISSIPATE OR
SHIFT ONSHORE THROUGH THE NIGHT. THE PREVAILING FLOW WILL BE MORE
EASTERLY AND EVENTUALLY SOUTHEASTERLY AS THE NIGHT PROGRESSES. THE
PRESSURE GRADIENT WILL NOT BE AS TIGHT AND WIND SPEEDS ARE EXPECTED
TO TOP OUT IN THE 10-15 KT RANGE...MAINLY FOR THE GEORGIA WATERS
LATE TONIGHT. SEAS WILL BE 2-3 FT...HIGHEST BEYOND 20 NM. SHOWERS
AND STORMS ARE EXPECTED TO INCREASE FROM THE SOUTH LATE TONIGHT AND
COULD PRODUCE LOCALLY HEAVY RAINFALL...REDUCING VISIBILITIES AT
TIMES OVER THE WATERS.
THE INLAND WEDGE/COASTAL TROUGH REGIME WILL GRADUALLY YIELD TO
ATLANTIC HIGH PRESSURE WHICH WILL EXPAND WEST TUESDAY AND WILL
PREVAIL UNTIL LATE WEEK. AS A RESULT...EAST/NORTHWEST WINDS WILL
GIVE WAY TO SOUTHEAST WINDS TUESDAY...THEN WINDS WILL VEER TOWARD
THE SOUTH/SOUTHWEST TUESDAY NIGHT THROUGH FRIDAY. THROUGH
MIDWEEK...WINDS MAINLY 10-15 KT AND SEAS 1-3 FT WILL PREVAIL.
THEN...AHEAD OF AN APPROACHING COLD FRONT THE GRADIENT WILL
TIGHTEN...AND WINDS WILL INCREASE TO 15-20 KT AND SEAS WILL BUILD TO
2-4 FT. WHILE THE PROBABILITY FOR SMALL CRAFT ADVISORY CONDITIONS
WILL INCREASE THROUGH THE LATTER HALF OF THE WEEK...GUIDANCE
MAINTAINS WINDS LESS THAN 25 KT AND SEAS BELOW 6 FT THROUGH THE
PERIOD. THE COLD FRONT WILL ADVANCE IN THE WATERS AND WILL STALL
NEXT WEEKEND...SO WINDS/SEAS REMAIN UNCERTAIN AND WILL DEPEND ON THE
TIMING/POSITION OF THE FRONT.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
ST
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
115 PM EDT MON SEP 7 2015
.SYNOPSIS...
BROAD UPPER LEVEL LOW OVER THE SOUTHEASTERN STATES WILL SHIFT
SOUTHWESTWARD INTO THE GULF OF MEXICO THROUGH TUESDAY AS SURFACE
HIGH PRESSURE BUILDS IN FROM THE NORTH. DEEP AND MOIST FLOW FROM
THE ATLANTIC WILL CONTINUE ACROSS THE REGION. AN UPPER RIDGE WILL
BUILD OVER THE AREA BY MID WEEK BRINGING WARMING TEMPERATURES. A
COLD FRONT AND UPPER TROUGH WILL BRING UNSETTLED WEATHER FOR THE
END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
SURFACE HIGH PRESSURE OVER THE MID-ATLANTIC STATES WILL CONTINUE
TO RIDGE INTO THE CAROLINAS AND GEORGIA THROUGH TONIGHT. BROAD UPPER
LEVEL LOW CENTERED OVER AL/GA BORDER WILL SHIFT SOUTHWESTWARD
INTO THE GULF OF MEXICO. DEEP AND MOIST FLOW FROM THE ATLANTIC
COMBINED WITH WEAK INSTABILITY WILL HOLD THE CHANCE OF SHOWERS AND
THUNDERSTORMS ACROSS THE AREA THOUGH THE EVENING. MOSTLY CLOUDY
SKIES EXPECTED.
SPC HRRR INDICATING SCATTERED CONVECTION PUSHING INTO THE AREA
FROM THE COAST THIS AFTERNOON. CHANCE POPS LOOK REASONABLE FOR
THE AFTERNOON. PRECIPITABLE WATER VALUES GENERALLY AT OR ABOVE 2.0
INCHES SO LOCALLY HEAVY RAIN POSSIBLE. CONVECTION SHOULD WEAKEN
DURING THE EVENING HOURS WITH LOSS OF DAYTIME HEATING.
HIGH TEMPERATURES EXPECTED TO REACH THE MID AND UPPER 80S WITH
LOWS TONIGHT IN THE UPPER 60S TO LOWER 70S.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
WEAK UPPER RIDGING WILL CONTINUE TO EXPAND WESTWARD OVER THE
SOUTHEASTERN STATES FROM THE WESTERN ATLANTIC. A SOUTHEASTERLY
SURFACE FLOW WILL BE BRINGING MOISTURE INTO THE REGION OFF THE
ATLANTIC. PRECIPITABLE WATER VALUES WILL GRADUALLY INCREASE TO
AROUND 2 INCHES BY TUESDAY AFTERNOON AND REMAIN HIGH THROUGH THE
PERIOD AS A DEEPER SOUTH TO SOUTHWESTERLY FLOW PATTERN DEVELOPS
THROUGH THE MID AND UPPER LEVELS OF THE ATMOSPHERE IN RESPONSE TO A
TROUGH MOVING THROUGH THE UPPER MISSISSIPPI AND OHIO VALLEYS.
SEE NO REASON TO CHANGE MUCH WITH THE CURRENT HIGH CHANCE POPS THAT
ARE IN THE CURRENT FORECAST EACH AFTERNOON FOR TUESDAY AND
WEDNESDAY. THERE MAY BE SOME BREAKS IN THE ACTION EACH NIGHT...BUT
WILL CONTINUE WITH SLIGHT CHANCE POPS FOR THE OVERNIGHT HOURS. THE
THREAT OF SEVERE WEATHER REMAIN LOW. BIGGEST ISSUE MAY BE DEALING
WITH PERIODS OF HEAVY RAINFALL IN ANY SLOWER MOVING SHOWERS/STORMS
THAT DEVELOP...ESPECIALLY WITH THE MOIST PROFILES AND WEAK SHEAR.
TEMPERATURES BOTH TUESDAY AND WEDNESDAY WILL WARM UP INTO THE LOWER
90S FOR AFTERNOON HIGHS...AND THE LOWER 70S FOR MORNING LOWS.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
BOTH THE GFS AND ECMWF ADVERTISE A WEAK TROUGH MOVING INTO AND
THROUGH THE REGION ON THURSDAY...WITH THE GFS BEING SLIGHTLY
FASTER BUT NOT BY MUCH. DO EXPECT SCATTERED CONVECTION TO DEVELOP
ACROSS THE REGION IN RESPONSE TO THIS TROUGH PUSHING TOWARDS AND
THROUGH THE AREA ON THURSDAY AFTERNOON/EVENING.
THE MODELS THEN BEGIN TO DIVERGE FROM FRIDAY INTO NEXT WEEK. BOTH
BRING A SECOND DEEPER UPPER TROUGH INTO THE EASTERN UNITED
STATES...BUT THE ECMWF IS MORE AGGRESSIVE AND DEEPER WITH CUTTING
THIS LOW OFF BY SATURDAY MORNING...WHILE THE GFS IS SLOWER IN ITS
MOVEMENT AND TENDS TO KEEP IT AS AN OPEN WAVE SATURDAY. GFS DOES
BEGIN TO CUT THE LOW OFF SATURDAY NIGHT INTO SUNDAY...BUT REMAINS
WEAKER AND FURTHER SOUTH WITH ITS LOW. WITH BOTH SOLUTIONS THE
UPPER FLOW REMAINS SOUTHWESTERLY THROUGH SUNDAY...THEN TURNS
WESTERLY BY MONDAY AS THE UPPER SYSTEM PUSHES OFF THE EAST COAST.
THE SURFACE FRONT ASSOCIATED WITH THE UPPER LOW MOVES CLOSER TO
BUT JUST WEST OF THE REGION THROUGH SATURDAY...BEFORE PUSHING EAST
OF THE AREA SATURDAY NIGHT INTO SUNDAY.
WILL CONTINUE MENTION OF HIGH CHANCE POPS FRIDAY INTO SATURDAY. THEN
BY SUNDAY POPS DIMINISH SOMEWHAT DOWN TO SLIGHT CHANCE/CHANCE
CATEGORY...WITH THE FOCUS OF HIGHER POPS SHIFTING TO THE
SOUTHEASTERN PART OF THE AREA. POPS MAY TREND LOWER NEAR THE END OF
THE PERIOD IF DRIER AIR CAN PUSH FAR ENOUGH INTO THE CWA BY THE
BEGINNING OF NEXT WEEK.
TEMPERATURES DURING THIS PERIOD WILL GENERALLY BE ABOVE NORMAL EARLY
IN THE PERIOD AND NEAR NORMAL OVER THE WEEKEND AND INTO NEXT WEEK.
&&
.AVIATION /17Z MONDAY THROUGH FRIDAY/...
CHANCE FOR SHOWERS WITH ISOLATED THUNDER IN DEEP AND MOIST
EASTERLY FLOW GIVEN WEAK INSTABILITY. THE BEST CHANCE SOUTH AND
EAST...FROM OGB TO AGS/DNL. WILL MENTION VCSH MAINLY FOR THE
AFTERNOON AND EARLY EVENING HOURS. WINDS WILL BE OUT OF THE
NORTHEAST TO EAST AT 10 KNOTS OR LESS. MODELS INDICATING MVFR/IFR
CIGS RETURNING AFTER 08/06Z.
EXTENDED AVIATION OUTLOOK...LATE NIGHT/MORNING FOG/STRATUS
POSSIBLE...WITH A CHANCE OF AFTERNOON SHOWERS AND POSSIBLE
THUNDERSTORMS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
99
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
958 AM EDT MON SEP 7 2015
.SYNOPSIS...
BROAD UPPER LEVEL LOW OVER THE SOUTHEASTERN STATES WILL SHIFT
SOUTHWESTWARD INTO THE GULF OF MEXICO THROUGH TUESDAY AS SURFACE
HIGH PRESSURE BUILDS IN FROM THE NORTH. DEEP AND MOIST FLOW FROM
THE ATLANTIC WILL CONTINUE ACROSS THE REGION. AN UPPER RIDGE WILL
BUILD OVER THE AREA BY MID WEEK BRINGING WARMING TEMPERATURES. A
COLD FRONT AND UPPER TROUGH WILL BRING UNSETTLED WEATHER FOR THE
END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
SURFACE HIGH PRESSURE OVER THE MID-ATLANTIC STATES WILL CONTINUE
TO RIDGE INTO THE CAROLINAS AND GEORGIA THROUGH TONIGHT. BROAD UPPER
LEVEL LOW CENTERED OVER AL/GA BORDER WILL SHIFT SOUTHWESTWARD
INTO THE GULF OF MEXICO. DEEP AND MOIST FLOW FROM THE ATLANTIC
COMBINED WITH WEAK INSTABILITY WILL HOLD THE CHANCE OF SHOWERS AND
THUNDERSTORMS ACROSS THE AREA THOUGH THE EVENING. MOSTLY CLOUDY
SKIES EXPECTED.
SPC HRRR INDICATING SCATTERED CONVECTION PUSHING INTO THE AREA
FROM THE COAST THIS AFTERNOON. CHANCE POPS LOOK REASONABLE FOR
THE AFTERNOON. PRECIPITABLE WATER VALUES GENERALLY AT OR ABOVE 2.0
INCHES SO LOCALLY HEAVY RAIN POSSIBLE. CONVECTION SHOULD WEAKEN
DURING THE EVENING HOURS WITH LOSS OF DAYTIME HEATING.
HIGH TEMPERATURES EXPECTED TO REACH THE MID AND UPPER 80S WITH
LOWS TONIGHT IN THE UPPER 60S TO LOWER 70S.
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
CLOSED UPPER LOW CENTERED ALONG THE GULF COAST STATES WILL CONTINUE
TO SLOWLY RETROGRADE AND FILL...WHILE WEAK UPPER RIDGING EXPANDS
OVER THE SOUTHEASTERN STATES FROM THE WESTERN ATLANTIC. THE SURFACE
PATTERN IS WEAK WITH HIGH PRESSURE CENTERED OVER VIRGINIA WEAKENING
WHILE A PERSISTENT SOUTHEASTERLY FLOW CONTINUES TO USHER MOISTURE
INLAND OFF THE ATLANTIC. PRECIPITABLE WATER VALUES WILL GRADUALLY
INCREASE TO AROUND 2 INCHES BY TUESDAY AFTERNOON AND REMAIN HIGH
THROUGH WEDNESDAY AS SOUTHERLY WINDS DEVELOP THROUGH THE LOWEST
20KFT OF THE ATMOSPHERE IN RESPONSE TO A TROUGH MOVING THROUGH THE
UPPER MISSISSIPPI AND OHIO VALLEYS.
WILL CONTINUE TO ADVERTISE HIGH CHANCE POPS ACROSS MUCH OF THE
REGION ON TUESDAY WITH THE HIGHEST POPS ACROSS THE SOUTHERN HALF OF
THE FORECAST AREA. THE THREAT OF SEVERE WEATHER APPEARS LOW WITH
PREDOMINATELY MOIST PROFILES AND WEAK SHEAR BUT HEAVY RAIN MAY BE A
CONCERN WITH STRONGER AND SLOW MOVING STORMS. SCATTERED UNORGANIZED
CONVECTION AGAIN EXPECTED ON WEDNESDAY WITH CONTINUED ELEVATED
MOISTURE PROFILES AND SLIGHTLY BETTER INSTABILITY. TEMPERATURES ON
TUESDAY AND WEDNESDAY WILL BE WARMER THAN THE PREVIOUS COUPLE OF
DAYS AND EXPECT HIGHS TO PUSH BACK INTO THE LOWER 90S WITH LOWS IN
THE LOWER 70S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
THE EXTENDED FORECAST FEATURES WHAT LOOKS LIKE AN ACTIVE WEATHER
REGIME WITH A MEAN TROUGH SETTING UP ACROSS THE EASTERN HALF OF
THE COUNTRY. AN INITIAL UPPER TROUGH WILL PUSH INTO THE REGION
FROM THE NORTHWEST ON THURSDAY RESULTING IN HEIGHT FALLS WHILE A
SURFACE TROUGH DEVELOPS OVER THE FORECAST AREA. THE SHORTWAVE
TROUGH IS FORECAST TO TRAVERSE THE FORECAST AREA THURSDAY NIGHT
INTO FRIDAY AND PUSH OFFSHORE BY FRIDAY NIGHT AS A COLD FRONT
PUSHES INTO THE AREA AND STALLS. THE FRONT WILL REMAIN STATIONARY
OVER THE REGION SATURDAY PROVIDING A FOCUS FOR PRECIPITATION AS
SOUTHWESTERLY FLOW ALOFT INCREASES IN ADVANCE OF ANOTHER SHORTWAVE
TROUGH DIGGING ACROSS THE OHIO VALLEY. THIS TROUGH WILL PUSH YET
ANOTHER FRONT INTO THE REGION BY EARLY SUNDAY AS A 1020MB SURFACE
RIDGE SETTLES ACROSS THE OHIO VALLEY INTO THE MID ATLANTIC STATES
BY SUNDAY NIGHT.
WILL CONTINUE MENTION OF SOLID CHANCE POPS THURSDAY AND FRIDAY WITH
THE FOCUS OF HIGHER POPS SHIFTING TO THE SOUTHEASTERN PART OF THE
AREA ON SATURDAY AND SUNDAY. TEMPERATURES DURING THIS PERIOD WILL
GENERALLY BE ABOVE NORMAL EARLY IN THE PERIOD AND NEAR NORMAL OVER
THE WEEKEND.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
MVFR CIGS EXPECTED TO LIFT TO VFR AROUND MID-DAY WHICH ALIGNS
WELL WITH THE PERSISTENCE FORECAST. CHANCE FOR SHOWERS WITH
ISOLATED THUNDER IN DEEP AND MOIST EASTERLY FLOW GIVEN WEAK
INSTABILITY. THE BEST CHANCE SOUTH AND EAST...FROM OGB TO AGS/DNL.
WILL MENTION VCSH MAINLY FOR THE AFTERNOON AND EARLY EVENING
HOURS. WINDS WILL BE OUT OF THE NORTHEAST TO EAST AT 10 KNOTS OR
LESS. MODELS INDICATING MVFR/IFR CIGS RETURNING AFTER 08/06Z.
EXTENDED AVIATION OUTLOOK...LATE NIGHT/MORNING FOG/STRATUS
POSSIBLE...WITH A CHANCE OF AFTERNOON SHOWERS AND POSSIBLE
THUNDERSTORMS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
643 AM EDT MON SEP 7 2015
.SYNOPSIS...
AN UPPER LOW OVER THE FORECAST AREA WILL SHIFT SOUTHWESTWARD
THROUGH TODAY WITH A COOL AND MOIST FLOW OFF THE ATLANTIC. AN
UPPER RIDGE WILL BUILD OVER THE AREA BY MID WEEK BRINGING WARMING
TEMPERATURES. A COLD FRONT AND UPPER TROUGH WILL BRING UNSETTLED
WEATHER FOR THE END OF THE WEEK.
&&
.NEAR TERM /TODAY AND TONIGHT/...
SURFACE ANALYSIS SHOWS AN AREA OF HIGH PRESSURE CENTERED OVER NEW
ENGLAND CONTINUING TO RIDGE DOWN THE EAST COAST INTO THE
CAROLINAS. MEANWHILE AN UPPER AREA OF LOW PRESSURE IS MOVING
WESTWARD THROUGH THE SOUTHEAST.
LATEST RADAR LOOP SHOWING SCATTERED SHOWERS BEING CONFINED MAINLY TO
THE IMMEDIATE COAST AND LOWCOUNTRY. GFS INDICATING WEAK COASTAL
SURFACE TROUGH MOVING ONSHORE LATER TODAY. SPC HRRR INDICATING
SCATTERED CONVECTION PUSHING INTO THE AREA FROM THE COAST LATER
THIS AFTERNOON. CHANCE POPS LOOK REASONABLE FOR THE AFTERNOON.
PRECIPITABLE WATER VALUES GENERALLY AT OR ABOVE 2.0 INCHES SO
LOCALLY HEAVY RAIN POSSIBLE. CONVECTION SHOULD WEAKEN DURING THE
EVENING HOURS WITH LOSS OF DAYTIME HEATING. AFTERNOON HIGHS MOSTLY
IN THE MIDDLE 80S WITH OVERNIGHT LOWS EARLY TUESDAY MORNING AROUND
70.
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
CLOSED UPPER LOW CENTERED ALONG THE GULF COAST STATES WILL CONTINUE
TO SLOWLY RETROGRADE AND FILL...WHILE WEAK UPPER RIDGING EXPANDS
OVER THE SOUTHEASTERN STATES FROM THE WESTERN ATLANTIC. THE SURFACE
PATTERN IS WEAK WITH HIGH PRESSURE CENTERED OVER VIRGINIA WEAKENING
WHILE A PERSISTENT SOUTHEASTERLY FLOW CONTINUES TO USHER MOISTURE
INLAND OFF THE ATLANTIC. PRECIPITABLE WATER VALUES WILL GRADUALLY
INCREASE TO AROUND 2 INCHES BY TUESDAY AFTERNOON AND REMAIN HIGH
THROUGH WEDNESDAY AS SOUTHERLY WINDS DEVELOP THROUGH THE LOWEST
20KFT OF THE ATMOSPHERE IN RESPONSE TO A TROUGH MOVING THROUGH THE
UPPER MISSISSIPPI AND OHIO VALLEYS.
WILL CONTINUE TO ADVERTISE HIGH CHANCE POPS ACROSS MUCH OF THE
REGION ON TUESDAY WITH THE HIGHEST POPS ACROSS THE SOUTHERN HALF OF
THE FORECAST AREA. THE THREAT OF SEVERE WEATHER APPEARS LOW WITH
PREDOMINATELY MOIST PROFILES AND WEAK SHEAR BUT HEAVY RAIN MAY BE A
CONCERN WITH STRONGER AND SLOW MOVING STORMS. SCATTERED UNORGANIZED
CONVECTION AGAIN EXPECTED ON WEDNESDAY WITH CONTINUED ELEVATED
MOISTURE PROFILES AND SLIGHTLY BETTER INSTABILITY. TEMPERATURES ON
TUESDAY AND WEDNESDAY WILL BE WARMER THAN THE PREVIOUS COUPLE OF
DAYS AND EXPECT HIGHS TO PUSH BACK INTO THE LOWER 90S WITH LOWS IN
THE LOWER 70S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
THE EXTENDED FORECAST FEATURES WHAT LOOKS LIKE AN ACTIVE WEATHER
REGIME WITH A MEAN TROUGH SETTING UP ACROSS THE EASTERN HALF OF
THE COUNTRY. AN INITIAL UPPER TROUGH WILL PUSH INTO THE REGION
FROM THE NORTHWEST ON THURSDAY RESULTING IN HEIGHT FALLS WHILE A
SURFACE TROUGH DEVELOPS OVER THE FORECAST AREA. THE SHORTWAVE
TROUGH IS FORECAST TO TRAVERSE THE FORECAST AREA THURSDAY NIGHT
INTO FRIDAY AND PUSH OFFSHORE BY FRIDAY NIGHT AS A COLD FRONT
PUSHES INTO THE AREA AND STALLS. THE FRONT WILL REMAIN STATIONARY
OVER THE REGION SATURDAY PROVIDING A FOCUS FOR PRECIPITATION AS
SOUTHWESTERLY FLOW ALOFT INCREASES IN ADVANCE OF ANOTHER SHORTWAVE
TROUGH DIGGING ACROSS THE OHIO VALLEY. THIS TROUGH WILL PUSH YET
ANOTHER FRONT INTO THE REGION BY EARLY SUNDAY AS A 1020MB SURFACE
RIDGE SETTLES ACROSS THE OHIO VALLEY INTO THE MID ATLANTIC STATES
BY SUNDAY NIGHT.
WILL CONTINUE MENTION OF SOLID CHANCE POPS THURSDAY AND FRIDAY WITH
THE FOCUS OF HIGHER POPS SHIFTING TO THE SOUTHEASTERN PART OF THE
AREA ON SATURDAY AND SUNDAY. TEMPERATURES DURING THIS PERIOD WILL
GENERALLY BE ABOVE NORMAL EARLY IN THE PERIOD AND NEAR NORMAL OVER
THE WEEKEND.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
MVFR TO POSSIBLY IFR CIGS POSSIBLE UNTIL AROUND 14Z-15Z THIS
MORNING. MODELS SHOW IMPROVEMENT AROUND MID- DAY TO EARLY
AFTERNOON WHICH ALIGNS WELL WITH THE PERSISTENCE FORECAST. ANOTHER
CHANCE FOR CONVECTION LATER THIS AFTERNOON WITH THE BEST CHANCE
SOUTH AND EAST. WILL MENTION VCSH MAINLY FOR THE AFTERNOON AND
EARLY EVENING HOURS. WINDS WILL GENERALLY BE OUT OF THE NORTHEAST
THROUGH THE PERIOD AT 10 KNOTS OR LESS.
EXTENDED AVIATION OUTLOOK...LATE NIGHT/MORNING FOG/STRATUS
POSSIBLE...WITH A CHANCE OF AFTERNOON SHOWERS AND POSSIBLE
THUNDERSTORMS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
87
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
322 AM EDT MON SEP 7 2015
.SYNOPSIS...
AN UPPER LOW OVER THE FORECAST AREA WILL SHIFT SOUTHWESTWARD
THROUGH TODAY WITH A COOL AND MOIST FLOW OFF THE ATLANTIC. AN
UPPER RIDGE WILL BUILD OVER THE AREA BY MID WEEK BRINGING WARMING
TEMPERATURES. A COLD FRONT AND UPPER TROUGH WILL BRING UNSETTLED
WEATHER FOR THE END OF THE WEEK.
&&
.NEAR TERM /TODAY AND TONIGHT/...
SURFACE ANALYSIS SHOWS AN AREA OF HIGH PRESSURE CENTERED OVER NEW
ENGLAND CONTINUING TO RIDGE DOWN THE EAST COAST INTO THE
CAROLINAS. MEANWHILE AN UPPER AREA OF LOW PRESSURE IS MOVING
WESTWARD THROUGH THE SOUTHEAST.
LATEST RADAR LOOP SHOWING SCATTERED SHOWERS BEING CONFINED MAINLY TO
THE IMMEDIATE COAST. GFS INDICATING WEAK COASTAL SURFACE TROUGH
MOVING ONSHORE LATER TODAY. SPC HRRR INDICATING SCATTERED CONVECTION
PUSHING INTO THE AREA FROM THE COAST LATER THIS AFTERNOON. CHANCE
POPS LOOK REASONABLE FOR THE AFTERNOON. PRECIPITABLE WATER VALUES
GENERALLY AT OR ABOVE 2.0 INCHES SO LOCALLY HEAVY RAIN POSSIBLE.
CONVECTION SHOULD WEAKEN DURING THE EVENING HOURS WITH LOSS OF
DAYTIME HEATING. AFTERNOON HIGHS MOSTLY IN THE MIDDLE 80S WITH
OVERNIGHT LOWS EARLY TUESDAY MORNING AROUND 70.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/...
CLOSED UPPER LOW CENTERED ALONG THE GULF COAST STATES WILL CONTINUE
TO SLOWLY RETROGRADE AND FILL...WHILE WEAK UPPER RIDGING EXPANDS
OVER THE SOUTHEASTERN STATES FROM THE WESTERN ATLANTIC. THE SURFACE
PATTERN IS WEAK WITH HIGH PRESSURE CENTERED OVER VIRGINIA WEAKENING
WHILE A PERSISTENT SOUTHEASTERLY FLOW CONTINUES TO USHER MOISTURE
INLAND OFF THE ATLANTIC. PRECIPITABLE WATER VALUES WILL GRADUALLY
INCREASE TO AROUND 2 INCHES BY TUESDAY AFTERNOON AND REMAIN HIGH
THROUGH WEDNESDAY AS SOUTHERLY WINDS DEVELOP THROUGH THE LOWEST
20KFT OF THE ATMOSPHERE IN RESPONSE TO A TROUGH MOVING THROUGH THE
UPPER MISSISSIPPI AND OHIO VALLEYS.
WILL CONTINUE TO ADVERTISE HIGH CHANCE POPS ACROSS MUCH OF THE
REGION ON TUESDAY WITH THE HIGHEST POPS ACROSS THE SOUTHERN HALF OF
THE FORECAST AREA. THE THREAT OF SEVERE WEATHER APPEARS LOW WITH
PREDOMINATELY MOIST PROFILES AND WEAK SHEAR BUT HEAVY RAIN MAY BE A
CONCERN WITH STRONGER AND SLOW MOVING STORMS. SCATTERED UNORGANIZED
CONVECTION AGAIN EXPECTED ON WEDNESDAY WITH CONTINUED ELEVATED
MOISTURE PROFILES AND SLIGHTLY BETTER INSTABILITY. TEMPERATURES ON
TUESDAY AND WEDNESDAY WILL BE WARMER THAN THE PREVIOUS COUPLE OF
DAYS AND EXPECT HIGHS TO PUSH BACK INTO THE LOWER 90S WITH LOWS IN
THE LOWER 70S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
THE EXTENDED FORECAST FEATURES WHAT LOOKS LIKE AN ACTIVE WEATHER
REGIME WITH A MEAN TROUGH SETTING UP ACROSS THE EASTERN HALF OF THE
COUNTRY. AN INITIAL UPPER TROUGH WILL PUSH INTO THE REGION FROM THE
NORTHWEST ON THURSDAY RESULTING IN HEIGHT FALLS WHILE A SURFACE
TROUGH DEVELOPS OVER THE FORECAST AREA. THE SHORTWAVE TROUGH IS
FORECAST TO TRAVERSE THE FORECAST AREA THURSDAY NIGHT INTO FRIDAY
AND PUSH OFFSHORE BY FRIDAY NIGHT AS A COLD FRONT PUSHES INTO THE
AREA AND STALLS. THE FRONT WILL REMAIN STATIONARY OVER THE REGION
SATURDAY PROVIDING A FOCUS FOR PRECIPITATION AS SOUTHWESTERLY FLOW
ALOFT INCREASES IN ADVANCE OF ANOTHER SHORTWAVE TROUGH DIGGING
ACROSS THE OHIO VALLEY. THIS TROUGH WILL PUSH YET ANOTHER FRONT
INTO THE REGION BY EARLY SUNDAY AS A 1020MB SURFACE RIDGE SETTLES
ACROSS THE OHIO VALLEY INTO THE MID ATLANTIC STATES BY SUNDAY NIGHT.
WILL CONTINUE MENTION OF SOLID CHANCE POPS THURSDAY AND FRIDAY WITH
THE FOCUS OF HIGHER POPS SHIFTING TO THE SOUTHEASTERN PART OF THE
AREA ON SATURDAY AND SUNDAY. TEMPERATURES DURING THIS PERIOD WILL
GENERALLY BE ABOVE NORMAL EARLY IN THE PERIOD AND NEAR NORMAL OVER
THE WEEKEND.
&&
.AVIATION /07Z MONDAY THROUGH FRIDAY/...
MVFR TO POSSIBLY IFR CIGS COULD REDEVELOP AS A STRATUS DECK DEVELOPS
ACROSS THE REGION. A 20 TO 25 KNOT LOW LEVEL JET SHOULD RESULT IN
MAINLY STRATUS OVER FOG. MODELS SHOW IMPROVEMENT AROUND MID-DAY TO
EARLY AFTERNOON WHICH ALIGNS WELL WITH THE PERSISTENCE FORECAST.
ANOTHER CHANCE FOR CONVECTION LATER THIS AFTERNOON WITH THE BEST
CHANCE SOUTH AND EAST. WILL MENTION VCSH MAINLY FOR THE AFTERNOON
AND EARLY EVENING HOURS. WINDS WILL GENERALLY BE OUT OF THE
NORTHEAST THROUGH THE PERIOD AT 10 KNOTS OR LESS.
EXTENDED AVIATION OUTLOOK...LATE NIGHT/MORNING FOG/STRATUS
POSSIBLE...WITH A CHANCE OF AFTERNOON SHOWERS AND POSSIBLE
THUNDERSTORMS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1019 PM EDT TUE SEP 8 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 241 PM EDT TUE SEP 8 2015
A COLD FRONT WILL BRING RAIN CHANCES TO THE AREA INTO
THURSDAY...THEN ANOTHER FRONT AND AN UPPER LOW WILL BRING MORE
CHANCES FOR RAIN FRIDAY AND SATURDAY. MUCH COOLER AIR WILL MOVE IN
BEHIND THE FRONTS. HIGHS ONLY IN THE 60S ARE EXPECTED THIS WEEKEND.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 955 PM EDT TUE SEP 8 2015
RADAR MOSAIC SHOWS RAIN HAS COMPLETELY FALLEN APART AND COME TO AN
END ACROSS CENTRAL INDIANA...BUT ECHOES IN SOUTHERN ILLINOIS
CONTINUE TO MOVE TOWARD THE SOUTHWESTERN COUNTIES. EXPECT TO SEE
MOSTLY DRY CONDITIONS ACROSS THE AREA THE NEXT FEW HOURS BEFORE
COVERAGE STARTS TO INCREASE ACROSS THE SOUTHWESTERN COUNTIES AND
SLOWLY SPREAD TO THE NORTHEAST FROM THERE. WITH LITTLE INSTABILITY
HAVE DECREASED THUNDERSTORM WORDING TO SLIGHT CHANCE TO GO ALONG
WITH THE CHANCES FOR RAIN THAT WILL INCREASE LATER DURING THE
OVERNIGHT. TEMPERATURES IN THE NORTHWESTERN COUNTIES DROPPED A
DECENT BIT BEHIND THE SHOWERS AND HAD TO ADJUST THE LOWS THERE
DOWN A COUPLE DEGREES...BUT THINK BASED ON UPSTREAM TEMPERATURES
AND CLOUD COVER THAT THEY WILL NOT DROP MUCH MORE AND MAY INSTEAD
INCREASE A BIT OVERNIGHT WITH AN INCREASED PUSH OF WARM ADVECTION
IN THE LOW LEVELS.
&&
.SHORT TERM.../WEDNESDAY THROUGH FRIDAY/
ISSUED AT 241 PM EDT TUE SEP 8 2015
FOCUS IS ON CHANCES FOR RAIN THROUGH THE PERIOD. MODELS ARE CLOSE
ENOUGH THAT A BLEND WAS USED.
WITH AN UPPER TROUGH DEEPENING A BIT...A COLD FRONT MOVING
THROUGH...AND AN UPPER JET TO THE NORTHWEST...FEEL THAT MOST AREAS
ARE LIKELY TO SEE AT LEAST SOME RAIN ON WEDNESDAY. WILL CONTINUE
WITH LIKELY POPS ALL AREAS. WILL TIME THEM AS BEST CHANCES NORTHWEST
DURING THE MORNING AND SOUTHEAST LATER IN THE AFTERNOON.
WITH THE POSSIBILITY OF A SURFACE WAVE RIDING ALONG THE FRONT
WEDNESDAY NIGHT...KEPT POPS GOING ACROSS MUCH OF THE
AREA...WITH HIGHEST POPS SOUTHEAST CLOSEST TO THE FRONT.
KEPT SOME SLIGHT CHANCE POPS ACROSS THE SOUTH ON THURSDAY
MORNING UNTIL THE SYSTEM CLEARS THE AREA. DRY CONDITIONS WILL THEN
PERSIST THROUGH THURSDAY NIGHT.
A SECONDARY COLD FRONT WILL MOVE THROUGH ON FRIDAY WITH A
REINFORCING SHOT OF COOLER AIR. THE FRONT WILL NOT HAVE A LOT
MOISTURE TO WORK WITH...SO KEPT POPS LOW.
FOR TEMPERATURES THROUGH THE SHORT TERM...GENERALLY STAYED CLOSER TO
THE WARMER MAV AS THE COOLEST AIR WILL NOT ARRIVE UNTIL THE SECOND
FRONT ON FRIDAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
ISSUED AT 215 PM EDT TUE SEP 8 2015
ECMWF AND THE GFS SUGGEST AN UPPER LOW DIGGING OUT OF THE GREAT
LAKES ON FRIDAY AND INTO THE OHIO VALLEY BY SATURDAY. WITH THESE
DYNAMICS ALOFT...BUT LITTLE IN THE WAY OF DEEP
MOISTURE...CLOUDS...COOLER TEMPS AND LIGHT PRECIP LOOK REASONABLE.
WILL CONTINUE TO INCLUDE LOW CHC POPS FOR SHOWS AT THIS TIME.
THE GFS AND ECMWF DEPICT DIFFERENT SOLUTIONS TO THE EVOLUTION OF
THE LOW...THE GFS SHOWS THE UPPER LOW SLOWLY MEANDERING EAST INTO
APPALACHIA ON SUNDAY AND MONDAY...WHILE THE ECMWF INDICATES A
QUICK DEPARTURE TO THE EAST ON SUNDAY. IN EITHER CASE...INDIANA
LOOKS TO REMAIN ON THE DRY AND COOL WEST SIDE OF THE DEPARTING
SYSTEM. THUS WILL BEGIN TRENDING TOWARD A DRY FORECAST ON SUNDAY
THROUGH TUESDAY AS FLOW ALOFT BECOMES MORE NORTHWESTERLY EARLY
NEXT WEEK...LITTLE SUPPORT IS SEEN IN THE WAY OF FORCING DYNAMICS.
THUS HAVE TRENDED DRY DURING THAT TIME.
&&
.AVIATION /DISCUSSION FOR 090300Z TAF UPDATE/...
ISSUED AT 1019 PM EDT TUE SEP 8 2015
MADE MINOR ADJUSTMENTS TO THE FIRST FEW HOURS AT THE TERMINALS AS
MOST OF THE PRECIP HAS DIMINISHED. SCATTERED CONVECTION PERSISTS
OVER SOUTH CENTRAL ILLINOIS AS IT MOVES E/NE...BUT CLOUD TOPS ARE
WARMING AND PRECIP COVERAGE HAS LESSENED AS EVENING HAS PROGRESSED.
OTHER ADJUSTMENT WAS TO BRING IN MVFR CEILINGS A BIT FASTER AT BOTH
KHUF AND KLAF BASED ON CURRENT OBS OVER ILLINOIS. RAP 925MB RH PROGS
INDICATING DEEPER MOISTURE ADVECTING INTO THE REGION AFTER 06Z.
COULD FLIRT WITH IFR CEILINGS AT KLAF LATE TONIGHT.
00Z DISCUSSION FOLLOWS.
MVFR AND LOWER CONDITIONS POSSIBLE LATE TONIGHT AND WEDNESDAY
MORNING WITHIN RAIN SHOWERS...OTHERWISE VFR CONDITIONS EXPECTED.
AS EXPECTED...AREA OF RAIN SHOWERS GRADUALLY DIMINISHING IN
COVERAGE AND INTENSITY AS IT PUSHES INTO A MORE STABLE AIRMASS
OVER THE HOOSIER STATE. LITTLE IF ANY LIGHTNING NOW DETECTED
ALONG THE LINE...AND EXPECT FURTHER WEAKENING OVER THE NEXT FEW
HOURS. WILL CARRY VCSH AT ALL SITES FOR A FEW HOURS THROUGH THE
EVENING. IN ADDITION...POTENTIAL BRIEF WIND GUST IMPACT AT KIND AS
A WELL DEFINED OUTFLOW BOUNDARY HAS EXPANDED OUT AHEAD OF THE
CONVECTION. LIKELY TO SEE A 10-15 MINUTE PERIOD WITH WINDS
GUSTING TO NEAR 25KTS OUT OF THE NORTHWEST. WILL HIGHLIGHT THIS
IN A TEMPO GROUP BETWEEN 00Z AND 01Z.
SHOULD BE A LULL IN PRECIP COVERAGE OVERNIGHT BEFORE RETURNING
PRIOR TO DAYBREAK WEDNESDAY AS A WAVE OF LOW PRESSURE TRACKS
ALONG THE FRONT AND INTO THE REGION. NOT OVERLY IMPRESSED WITH
AVAILABLE INSTABILITY AND OUTSIDE OF AN ISOLATED THUNDER
THREAT...DO NO ANTICIPATE WIDESPREAD THUNDERSTORMS INTO THE DAY
WEDNESDAY AT THIS POINT. MODEL SOUNDINGS INDICATE POTENTIAL FOR
MVFR STRATUS TO IMPACT THE TERMINALS WEDNESDAY MORNING WITHIN RAIN
SHOWERS...WITH CEILINGS LIFTING TO BETWEEN 4000-5000FT WEDNESDAY
AFTERNOON.
RAIN CHANCES SHOULD GRADUALLY END FROM NORTHWEST TO SOUTHEAST
THROUGH THE AFTERNOON AS THE COLD FRONT SHIFTS SOUTH OF THE OHIO
RIVER. WIND DIRECTION WILL BE CHAOTIC BUT SPEEDS GENERALLY LESS
THAN 5-7KTS EXPECTED ON WEDNESDAY. WINDS WILL GRADUALLY BECOME
NORTHERLY WEDNESDAY NIGHT AS HIGH PRESSURE BUILDS IN.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...CP
SHORT TERM...50
LONG TERM....PUMA
AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1222 AM CDT MON SEP 7 2015
.SHORT TERM /TONIGHT/...
ISSUED AT 305 PM CDT SUN SEP 6 2015
STILL SOME UNCERTAINTY ABOUT EVOLUTION OF SYSTEM TONIGHT. VARIOUS
MODEL SOLUTIONS BEGINNING TO EITHER POINT TOWARD SLIGHTLY MORE
PROGRESSIVE EVOLUTION OF CONVECTION OVERNIGHT...OR SLIGHTLY MORE
NORTH PLACEMENT OF MAX.
SO FAR CONVECTIVE TRENDS HAVE BEEN RAMPING UP SLOWLY DUE TO H700
TEMPS SITTING ABOVE 11-12C THIS AFTERNOON. BUT AS FRONT ENTERS
NW/W IA EARLY THIS EVENING AND AREA BECOMES UNCAPPED AND H700
TEMPS COOL A COUPLE OF DEGREES...A RAPID INCREASE IN STORMS SHOULD
OCCUR BETWEEN 4 PM AND 7 PM. DESPITE THE EXPECTED MODEL
UNCERTAINTY...WE ARE IN NEAR RECORD TERRITORY FOR AVAILABLE
ATMOSPHERIC MOISTURE FOR EARLY SEPTEMBER. THIS IS DUE IN PART TO A
PROLONGED FETCH OF GULF MOISTURE WHICH IS FEEDING NORTHEAST INTO
THE CENTRAL PLAINS AND GREAT LAKES. SECONDLY...A TROPICAL
CONNECTION FROM THE SOUTHWEST US THAT RESULTED IN AN OLD TROPICAL
SYSTEM EARLIER IN THE WEEK OFF THE COAST OF BAJA MEXICO BEING
INGESTED IN THE MID TO UPPER LEVEL FLOW. PWAT VALUES WILL BE
APPROACHING 2 TO 2.25 INCHES BETWEEN 00-06Z TONIGHT PLACING OUR
VALUES IN THE 99TH/100TH PERCENTILE AND OVER 3 SDEV ABOVE NORMAL
FOR THIS TIME OF YEAR. WARM CLOUD DEPTHS ARE NEAR 14.5KFT WHICH IS
EXTREMELY DEEP. THERE REMAIN NUMEROUS FACTORS SUPPORTING
EFFICIENT/HIGH RAINFALL RATES THIS EVENING...AND LOOKING
AHEAD...AGAIN MONDAY NIGHT. BACK TO THE MODELS...CONSECUTIVE RUNS
OF THE HRRR ARE SHOWING A MORE PROGRESSIVE EVOLUTION TO TONIGHTS
CONVECTION WITH FORWARD PROPAGATING CORFIDI VECTORS ABOUT 20 KTS.
BUT EVEN THIS IS DECEIVING IF RAINFALL RATES ARE 2-3 INCHES PER
HOUR AT TIMES...AND STILL SUGGESTS A QUICK COUPLE OF INCHES OF
RAIN IN THE MORE VIGOROUS CELLS. WITH ANY LOCALIZED
TRAINING...STILL A POTENTIAL FOR ISOLATED 3 TO 4 INCHES AMOUNTS
OVERNIGHT. THE NAM IS LEANING TOWARD THE MORE PROGRESSIVE HRRR
OVERNIGHT WITH THE GFS RAMPING UP CONVECTION BETWEEN 00-06Z ON THE
NOSE OF THE INCREASING LOW LEVEL JET ALONG THE INVERTED TROUGH
WITHIN THE ZONE OF MAXIMUM SFC CONVERGENCE. THE QPF MAX IS
CENTERED OVER HIGHWAY 30...ROUGHLY BETWEEN US 20/I80 FROM GREENE
TO MARSHALL COUNTIES. WITH THAT ADDED UNCERTAINTY TONIGHT AND THE
POSSIBLE NORTHERLY SHIFT BY 20 MILES OF THE QPF MAX...WILL BE
ADDING ONE ROW OF COUNTIES TO TONIGHTS FFA ALONG US 20. REALIGNING
THE WATCH NOW IS RISKY...DUE TO THE POSSIBILITY OF THE MODELS ARE
NOT PROPERLY ACCOUNTING FOR A STRONGER OUTFLOW BOUNDARY LATER IN
THE EVENING...WHICH WOULD THEN BE FEEDING OFF AN INCREASING LOW
LEVEL JET OVERNIGHT. THERE MAY ACTUALLY BE TWO FAVORED AREAS OF
HEAVY RAINFALL...EARLIER BETWEEN US20/30 AND LATER ALONG AND SOUTH
OF I80. NONE THE LESS...THE RISK FOR FLASH FLOODING AND SUBSEQUENT
ISSUES REMAINS. TIMING OF THE EVENT SUGGESTS THAT STORMS SHOULD BE
IN FULL SWING BETWEEN 02-09Z WITH ACTIVITY REMAINING STRONG BUT
SLOWLY DIMINISHING BETWEEN 09-13Z MONDAY OVER THE SOUTH/SOUTHEAST.
LOWS TONIGHT WILL FALL TO THE LOWER 70S SOUTH TO NEAR 60 OVER THE
FAR NORTHWEST AS THE COOLER AIR BEGINS TO FILTER INTO THE REGION
TONIGHT. TONIGHTS RAINFALL WILL PRIME THE REGION FOR A MORE
SIGNIFICANT RISK OF FLOODING MONDAY NIGHT AND THIS IS COVERED IN
THE EXTENDED DISCUSSION.
.LONG TERM /MONDAY THROUGH SUNDAY/...
ISSUED AT 305 PM CDT SUN SEP 6 2015
A POTENTIALLY SIGNIFICANT HEAVY RAIN AND FLOODING EVENT MAY BE
SHAPING UP EARLY THIS WEEK.
THE COLD FRONT SAGGING DOWN INTO IOWA TONIGHT...AS DISCUSSED IN
THE SHORT TERM SECTION ABOVE...WILL LIKELY STALL ACROSS SOUTHERN
IOWA BY MONDAY MORNING THEN RETREAT BACK NORTHWARD A BIT TOWARD
CENTRAL IOWA DURING THE DAY. DESTABILIZATION WILL BE LIMITED BY
DEBRIS CLOUDS AND A LACK OF LOW LEVEL WARM AIR ADVECTION OVER
MOST OF THE FORECAST AREA...PLUS THERE WILL BE NO LARGE SCALE
FORCING MECHANISM FOR CONVECTION FOR MOST OF THE DAY. NEVERTHELESS
THE AIRMASS WILL BE JUICED ENOUGH WITH THE BOUNDARY WOBBLING
AROUND THAT LOW POPS ARE MAINTAINED ON MONDAY.
BEGINNING LATE MONDAY AFTERNOON AND ESPECIALLY ON MONDAY NIGHT THE
ATMOSPHERE APPEARS TO BE SETTING UP FOR A SIGNIFICANT...POSSIBLY
EXTREME HEAVY RAINFALL EVENT. ALONG AND SOUTH OF THE NEARLY
STATIONARY FRONTAL ZONE PWAT VALUES WILL BE NEAR RECORDS WITH
SUBSTANTIAL MOISTURE TRANSPORT CONTINUING FROM THE GULF ESPECIALLY
AS THE NOCTURNAL LOW LEVEL JET KICKS IN AFTER DARK.
CONCURRENTLY...A SECOND FAIRLY ROBUST MID LEVEL SHORTWAVE WILL
ROUND THE BASE OF BROAD CYCLONIC FLOW ALOFT AND PROVIDE A TRIGGER
FOR WIDESPREAD THUNDERSTORM DEVELOPMENT. WITH WARM CLOUD DEPTHS IN
EXCESS OF 15 KFT IN FORECAST SOUNDINGS AND THE COMBINATION OF
OTHER FACTORS...WE WILL BE PRIMED FOR VERY EFFICIENT RAINFALL
RATES AND POTENTIALLY TRAINING OR SLOW MOVING STORMS NEAR THE
FRONTAL ZONE. THIS COULD LEAD TO WIDESPREAD RAINFALL AMOUNTS IN
THE 2 TO 3 INCH RANGE WITHIN A BROAD SWATH ACROSS THE AREA...AND
LOCALIZED AMOUNTS OF 6 INCHES OR MORE ARE DEFINITELY CONCEIVABLE.
IN TERMS OF THE FLOODING EFFECTS OF SUCH RAINFALL...MUCH WILL
DEPEND ON WHERE IT FALLS AND WHETHER IT OCCURS IN THE SAME AREA AS
THE HEAVIEST RAINFALL TONIGHT...WHICH IS IN TURN DEPENDENT ON THE
DIFFICULT TO PREDICT MOTIONS AND LOCATION OF THE FRONTAL BOUNDARY
BY MONDAY EVENING. IT IS LIKELY...IN ANY EVENT...THAT A SECOND
FLASH FLOOD WATCH WILL BE NEEDED AFTER TONIGHTS RAINFALL PANS
OUT...AND THAT IT MAY NEED TO HAVE EVEN STRONGER WORDING FOR THE
POTENTIAL EFFECTS MONDAY NIGHT INTO TUESDAY MORNING.
SCATTERED THUNDERSTORMS MAY CONTINUE TO FESTER ACROSS OUR SOUTHERN
COUNTIES ON TUESDAY AS THE FRONTAL ZONE LINGERS NEAR THE
IOWA/MISSOURI BORDER...BUT THEN ANOTHER SHORTWAVE TROUGH WILL MOVE
OVERHEAD AROUND TUESDAY EVENING AND FINALLY CLEAR OUT THE WET
AIRMASS TO OUR SOUTH. THIS WILL BRING AN END OF ANY HEAVY RAIN
THREAT FOR THE REMAINDER OF THE SEVEN DAY FORECAST...ALONG WITH
NOTABLY COOLER AND DRIER WEATHER ACROSS IOWA. THERE WILL BE A
CHANCE FOR SCATTERED SHOWERS AND STORMS AROUND THURSDAY AS A
REINFORCING COLD FRONT SURGES ACROSS THE STATE...USHERING IN THE
FIRST TRULY AUTUMNAL WEATHER OF THE SEASON AT THE END OF THIS WEEK
WITH FRIDAY HIGHS IN THE 60S AND FRIDAY NIGHT LOWS IN THE 40S
STATEWIDE.
&&
.AVIATION...07/06Z
ISSUED AT 1222 AM CDT MON SEP 7 2015
SOME STORMS TO STILL IMPACT KOTM KDSM AND KALO THROUGH THE
OVERNIGHT HOURS...WITH FOG CHANCES AT THE NORTHERN SITES LOOKING
SOMEWHAT UNCERTAIN. WINDS TO SHIFT AROUND TO THE SOUTHEAST TO
SOUTH AGAIN LATE IN THE FORECAST PERIOD...WITH ANOTHER ROUND OF
STORMS POSSIBLE BEGINNING LATE MONDAY AFTERNOON INTO MONDAY NIGHT.
CIGS TO BE IN THE MVFR TO LOW VFR RANGE...BUT MAY DIP INTO IFR IF
FOG DEVELOPS.
&&
.HYDROLOGY...
ISSUED AT 305 PM CDT SUN SEP 6 2015
AS REFERENCED IN THE PREVIOUS DISCUSSIONS...TWO HEAVY
RAINFALL EVENTS ARE POSSIBLE TONIGHT THROUGH TUESDAY MORNING WITH
THE FOCUS FROM NORTH CENTRAL TO SOUTHERN IOWA. WIDESPREAD RAINFALL
AMOUNTS OF 2 TO 3 INCHES ARE EXPECTED WITH AMOUNTS EXCEEDING 5
INCHES POSSIBLE DURING THIS PERIOD. MONDAY NIGHTS EVENT IS STILL
EXPECTED TO BE OF GREATER MAGNITUDE...SO SOME REEVALUATION OF THE
WATCH OUTLINE WILL OCCUR BETWEEN THIS EVENING AND TOMORROW
MORNING AFTER TONIGHTS RAINFALL REPORTS ARE GATHERED. IN BOTH
EVENTS...EFFICIENT RAIN PRODUCING STORMS WILL PRODUCE HEAVY
RAINFALL OVER A SHORT PERIOD OF TIME. SIGNIFICANT RUNOFF AND/OR
PONDING OF WATER IS LIKELY IN SOME AREAS LEADING TO A FLASH FLOOD
THREAT. THE EVENT MAY EVOLVE INTO A RIVER FLOODING THREAT THROUGH
MID TO LATE WEEK AS THE RUNOFF REACHES THE LARGER STREAMS. THE
MAGNITUDE OF RIVER FLOODING ON ANY GIVEN MAINSTEM RIVER WILL
DEPEND ON BOTH RAINFALL AMOUNTS AND BASIN COVERAGE IN THE NEXT 48
TO 60 HOURS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 10 AM CDT THIS MORNING FOR ADAIR-ADAMS-
APPANOOSE-AUDUBON-BOONE-CASS-CLARKE-DALLAS-DAVIS-DECATUR-GREENE-
GUTHRIE-JASPER-LUCAS-MADISON-MAHASKA-MARION-MARSHALL-MONROE-POLK-
POWESHIEK-RINGGOLD-STORY-TAMA-TAYLOR-UNION-WAPELLO-WARREN-WAYNE.
&&
$$
SHORT TERM...REV
LONG TERM...LEE
AVIATION...BEERENDS
HYDROLOGY...REV
AREA FORECAST DISCUSSION
NWS GOODLAND KS
557 PM MDT TUE SEP 8 2015
.UPDATE...
ISSUED AT 539 PM MDT TUE SEP 8 2015
A FEW THUNDERSTORMS HAVE POPPED UP IN N-S ORIENTED INSTABILITY
AXIS ACROSS EASTERN HALF OF CWA. EXPECT CINH TO STEADILY INCREASE
OVER THE NEXT 2 HOURS WHICH WILL ULTIMATELY LIMIT THE COVERAGE
AND DURATION THROUGH THE EARLY EVENING. SEEMS TO BE A PRETTY SHARP
MOISTURE GRADIENT ACROSS THE AREA ATTM WITH DEWPOINTS AROUND 20
DEGREES COOLER IN THE WEST. WITH LIGHT WINDS AND CLEAR SKIES MAY
HAVE TO RETHINK LOW TEMPS...AND HAVE ALSO MODIFIED FOG FORECAST A
BIT TO REFLECT THIS ORIENTATION.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 222 PM MDT TUE SEP 8 2015
WV IMAGERY AND RAP H5 ANALYSIS SHOWS NW FLOW ACROSS CENTRAL ROCKIES
AND OVER OUR CWA ON WESTERN EXTENT OF LARGE SCALE TROUGH. AXIS OF
SUBSIDENCE IS CURRENTLY IN PLACE AS A SHORTWAVE TROUGH IS MOVING
ACROSS CENTRAL KANSAS. AT THE SURFACE HIGH PRESSURE IS BUILDING INTO
OUR CWA FROM THE NORTHERN PLAINS WITH A COLD FRONT THAT MOVED
THROUGH OUR CWA EARLY THIS MORNING EXTENDING FROM NORTHEAST KANSAS
THROUGH SOUTH CENTRAL KANSAS.
TONIGHT...DRY CONDITIONS SHOULD PERSIST THROUGH THE OVERNIGHT PERIOD
WITH SUBSIDENCE PERSISTING THROUGH MOST OF THE NIGHT...AND DEEP DRY
AIR MASS IN PLACE. EARLY IN THE EVENING STEEP LAPSE RATES LEE TROUGH
REBUILDS ALONG KS/CO BORDER OVERNIGHT WITH SOUTHERLY FLOW BRINING
HIGH BL MOISTURE IN PLACE. TREND IN GUIDANCE HAS BEEN TO TO SHOW
BETTER MIXING AND BL RH STAYING UP LIMITING FOG POTENTIAL. NAM AND
RAP DO STILL SHOW SOME REDUCED VISIBILITIES AND I FELT COMFORTABLE
KEEPING MENTION IN FORECAST FOR NOW.
WEDNESDAY...A QUICK MOVING/WEAK SHORTWAVE TROUGH WILL ROTATE THROUGH
NW FLOW JUST NORTH OF OUR CWA. DRY LAYER IN PLACE LOWERS OVERALL
CONFIDENCE IN COVERAGE...HOWEVER GUIDANCE IS SHOWING INITIATION
EITHER UPSTREAM OR ALONG SURFACE TROUGH AND TRACKING EAST ACROSS THE
NORTHERN HALF OF OUR CWA. IF A CELL WERE TO DEVELOP ML CAPE VALUES
AROUND 2000 J/KG AND EFFECTIVE SHEAR VALUES AROUND 35KT COULD
SUPPORT A LIMITED SEVERE THREAT. IM JUST NOT SURE IF ANYTHING WILL
EVEN DEVELOP CONSIDERING THE DRY AIR MASS IN PLACE. I KEPT SLIGHT
CHANCE POPS IN THE AFTERNOON...COVERING POTENTIAL.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 255 PM MDT TUE SEP 8 2015
SEVERAL SHORT WAVE TROUGHS MOVE ACROSS THE CENTRAL HIGH PLAINS
REGION WEDNESDAY NIGHT...THURSDAY NIGHT...AND FRIDAY EVENING. THE
UPPER PATTERN BECOMES MORE AMPLIFIED AS THE SHORT WAVE TROUGHS
DIVE INTO THE BASE OF THE MAIN UPPER TROUGH POSITIONED OVER THE
MISSISSIPPI VALLEY REGION AS THE UPPER RIDGE AMPLIFIES OVER THE
WESTERN UNITED STATES THURSDAY THROUGH FRIDAY NIGHT AND
TRANSITIONS EASTWARD OVER THE ROCKIES AND HIGH PLAINS SATURDAY
NIGHT.
WITH A SURFACE TROUGH/FRONTAL BOUNDARY REMAINING IN THE VICINITY
OF THE FORECAST AREA THESE SHORT WAVE TROUGHS TRANSITIONING THE
REGION WILL HELP ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
DEVELOP EACH DAY FROM LATE WEDNESDAY THROUGH EARLY FRIDAY. BY LATE
FRIDAY THE FRONTAL BOUNDARY HAS PUSHED SOUTH OF THE REGION AND
SURFACE HIGH PRESSURE MOVES INTO THE AREA. TEMPERATURES WILL WARM
THROUGH THURSDAY AHEAD OF THE FRONT WITH HIGH TEMPERATURES ONLY
EXPECTED TO REACH IN TO THE 70S ON FRIDAY. TEMPERATURES WILL
REBOUND QUICKLY THROUGH THE WEEKEND AND INTO NEXT WEEK AS
SOUTHERLY NEAR SURFACE FLOW RETURNS AND THE REGION REMAINS UNDER
WEAK RIDGING THROUGH THE WEEKEND AS THE UPPER PATTERN UNDERGOES A
TRANSITION TO A RIDGE OVER THE EASTERN HALF OF THE UNITED STATES
WHILE THE NEXT SIGNIFICANT LONG WAVE TROUGH DEEPENS OVER THE
WESTERN UNITES STATES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 539 PM MDT TUE SEP 8 2015
VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD WITH A SMALL WINDOW
BTWN 10Z AND 15Z WHERE FOG MAY DEVELOP. CHANCES ARE BEST AT MCK
BUT IT WILL NOT BE OUT OF THE QUESTION THAT GLD SEES AN HOUR OR
TWO OF IFR CONDITIONS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JRM
SHORT TERM...DR
LONG TERM...LOCKHART
AVIATION...JRM
AREA FORECAST DISCUSSION
NWS TOPEKA KS
428 PM CDT MON SEP 7 2015
.SHORT TERM...(THIS EVENING THROUGH Tuesday)
ISSUED AT 402 PM CDT MON SEP 7 2015
Showers and isolated storms continued off and on through the
afternoon hours in a zone of 1000-900mb convergence, weak isentropic
lift and the presence of a weak wave. Although the bulk of the
precipitation has moved east into missouri expect isolated to
scattered showers to continue across east central Kansas into the
early evening hours. Further north near the Nebraska border where
few clouds have allowed temperatures to warm into the lower to mid
90s. Latest measoanalysis shows about 40 to 50kts of effective shear,
1500-3000 J/kg of CAPE and no cap in place. Isolated thunderstorms
have developed just to the northwest of the forecast area and were
moving northeast across southern Nebraska at 1930Z. Latest runs of
the HRRR and the RAP suggest further development across north
central Kansas into the evening hours, with additional development
from central Kansas across northeast Kansas through the evening
hours. Storms that can develop across the northern counties may be
severe with hail, strong winds and an isolated tornado possible.
Another round of storms is expected overnight into Tuesday morning
as the upper level trough progresses eastward across the Northern
and Central Plains. Good moisture transport is expected into
northeast Kansas overnight with precipitable water around 2 inches
which will increase the potential for locally heavy rainfall. The
front is expected to move slowly southeast across the forecast area
on Tuesday then moving out of east central Kansas Tuesday evening.
Showers and thunderstorms will likely be ongoing in the morning hours
and then continue along the boundary in the afternoon.
Clouds south of I-70 have kept temperatures in check in the upper
70s to upper 80s. Will likely still see some fluctuations in
temperatures through the late afternoon where the sun can come out.
Tonight, lows should cool into the low to mid 70s with highs on
Tuesday only in the low to mid 80s.
.LONG TERM...(Tuesday NIGHT THROUGH Monday)
ISSUED AT 402 PM CDT MON SEP 7 2015
Cold front and associated showers and thunderstorms should be
moving to the southeast out of east central KS Tuesday evening.
Then surface high pressure builds in with pleasant temperatures
and lower humidities for Wednesday and Wednesday night.
Northwest flow aloft then sets up through the end of the week
with the first in a series of disturbances possibly affecting
north central KS by late Thursday afternoon. That system moves
through Thursday night through Friday with a good chance of
thunderstorms during this time.
Subsidence behind the trough and associated surface high pressure
builds in for Saturday, and an upper ridge builds eastward for
Sunday and Monday, keeping the weekend into Monday dry.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z Tuesday AFTERNOON)
ISSUED AT 1236 PM CDT MON SEP 7 2015
Currently a weak shortwave is still making its way over northeast
KS. A few showers remain to the South of the terminals, but trends
continue in weakening and decreasing coverage. Improvements in
CIGS at KTOP should continue over the next couple hours. The
balance of the afternoon and early evening look VFR at this point.
Confidence into the evening decreases with storm chances once
again in the overall picture. However, coverage and exact timing
are not certain. Have included VCTS in the overnight period again
as the Low Level Jet will still be influencing the terminals and
low- level boundary will still be a factor in the overall forecast
likely through the entire period.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...53
LONG TERM...GDP
AVIATION...Drake
AREA FORECAST DISCUSSION
NWS GOODLAND KS
306 PM MDT MON SEP 7 2015
.SHORT TERM...(THIS AFTERNOON THROUGH TUESDAY)
ISSUED AT 143 PM MDT MON SEP 7 2015
EARLY AFTERNOON WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOWS SW
FLOW IN PLACE ACROSS CENTRAL ROCKIES OVER OUR CWA...AND INTO THE
NORTHERN PLAINS. THIS IS AHEAD OF LARGE UPPER LOW CENTERED OVER
CENTRAL CANADA WITH BROAD TROUGHING EXTENDING SOUTH ACROSS THE
PACIFIC NORTHWEST. CHECKING DYNAMIC TROPOPAUSE...EMBEDDED WEAK
SHORTWAVE TROUGH THAT ROTATED THROUGH REGION THIS MORNING IS NOW
OVER NORTHCENTRAL KS WITH A STRONGER PV HEIGHT ANOMALY ENTERING
CENTRAL COLORADO. SUBSIDENCE BEHIND THE INITIAL FEATURE IS STILL
TRANSITIONING ACROSS MOSTLY OF OUR CWA. AT THE SURFACE A STALLED
FRONT IS JUST SOUTH OF INTERSTATE 70 WITH SURFACE LOW EXTENDING
FROM SOUTHERN COLORADO ACROSS SW KS AND INTO NW KANSAS.
THIS AFTERNOON-TUESDAY...FORCING IS EXPECTED TO INCREASE THIS
EVENING WITH NEXT SHORTWAVE TROUGH MOVING OUT OF THE CENTRAL ROCKIES
AND INTERACTING WITH STALLED FRONTAL ZONE OVER OUR CWA. THERE IS
THE POSSIBILITY FOR OVERRUNNING/BACKBUILDING ALONG ELEVATED FRONTAL
ZONE/STRENGTHENING H7 TROUGH AXIS AS THIS FEATURE MOVES ACROSS THE
REGION. EAST/NORTHEAST FLOW WILL CONTINUE TO ADVECTS BOUNTIFUL
MOISTURE OVER OUR CWA...WITH MODERATE INSTABILITY CONTINUING
THROUGH THE EVENING. CONFIDENCE IS LOWER REGARDING COVERAGE...WITH
FAIRLY LARGE SPREAD IN GUIDANCE SINCE OVERNIGHT AND SUBSIDENCE
INITIALLY IN PLACE OVER OUR CWA. CURRENT ARW/NMM DEPICTS ACTIVITY
INITIATING WEST OF OUR CWA...OR OVER OUR WESTERN CWA AROUND 00Z AND
TRACKING ALONG/NORTH OF FRONT THIS EVENING/OVERNIGHT BEFORE SLOWLY
TRANSITIONING EAST. HRRR/RAP BOTH SUPPORT A SIMILAR LOCATION AND
TIMING...HOWEVER SHOW MUCH LESS IN THE WAY OF COVERAGE. I FELT
COMFORTABLE ADJUSTING THE TIMING TO FAVOR THIS EVENING FOR BEST
COVERAGE AND KEPT MENTION LIMITED TO CHANCE FOR NOW. GUIDANCE SHOWS
BAROCLINIC ZONE LINGERING THROUGH EARLY AFTERNOON TUESDAY ACROSS OUR
SOUTHEAST WITH ADDITIONAL SHOWER/THUNDERSTORM DEVELOPMENT POSSIBLE.
I SHOWED GRADUAL TRANSITION TO THE EAST/SOUTHEAST IN LINE WITH
MODEL CONSENSUS.
REGARDING SEVERE THREAT...HIGH LOW LEVEL MIXING RATIOS HAVE AIDED IN
MODERATE INSTABILITY BUILDING ACROSS OUR CWA WITH ML CAPE 1500-2500
J/KG DEPICTED ON RAP ANALYSIS. DEEP UNIDIRECTIONAL FLOW HAS LED TO
HIGH SHEAR IN MID TO UPPER LEVELS WITH EFFECTIVE SHEER VALUES
ALREADY IN EXCESS OF 50KT OVER OUR CWA. BEST LOW LEVEL SHEAR IS
OVER NORTH CENTRAL KS/NEAR HILL CITY ASSOCIATED WITH VEERING NEAR
WHERE CLOSED SURFACE LOW MAY BE DEVELOPING BASED ON WIND/PRESSURE
FIELD. SEVERE THREAT SHOULD PREDOMINANTLY BE CONFINED TO LARGE
HAIL/DAMAGING WINDS...HOWEVER LOCATIONS IN THE FAR EASTERN PART OF
OUR CWA COULD SEE FAVORABLE CONDITIONS FOR SUPERCELL DEVELOPMENT
AND TORNADO RISK. WINDOW FOR THIS SHOULD BE CONFINED TO THIS
AFTERNOON/EARLY EVENING WITH FRONT TRANSITIONING BACK TO THE
SOUTHEAST THIS EVENING.
RAP/HRRR/NAM/SREF CONTINUE TO SHOW STRATUS/FOG REDEVELOPING ACROSS
NEBRASKA AND ADVECTING/SPREADING SOUTHWEST ACROSS OUR CWA. LOWEST
VIS COULD APPROACH DENSE FOG ADVISORY CRITERIA...THOUGH IT DOES
APPEAR TO BE FAIRLY TRANSIENT REGARDING LOWEST VISIBILITIES. FOR NOW
I KEPT AREAS OF FOG MENTION...AND WILL ALLOW SUBSEQUENT SHIFTS TO
MONITOR NEED FOR NEW DENSE FOG ADVISORY.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 230 PM MDT MON SEP 7 2015
THE WESTERLY FLOW ALOFT ACROSS THE CENTRAL HIGH PLAINS TURNS NORTHWESTERLY
BY THURSDAY AND MORE NORTHERLY BY FRIDAY AND SATURDAY AS THE HIGH
PRESSURE AREA ALOFT OVER NORTHERN MEXICO RETROGRADES AND MERGES
WITH THE HIGH IN THE EASTERN PACIFIC TO FORM A RIDGE OVER THE
WESTERN UNITED STATES WHILE SHORT WAVES EMBEDDED IN THE UPPER
FLOW MOVE THROUGH THE CENTRAL HIGH PLAINS AND INTO THE BASE OF THE
TROUGH DEEPENING IN THE MISSISSIPPI VALLEY REGION. EXPECT ISOLATED
TO SCATTERED SHOWERS AND THUNDERSTORMS FROM WEDNESDAY NIGHT
THROUGH FRIDAY NIGHT AS A RESULT OF THESE DISTURBANCES MOVING
ACROSS THE REGION WITH THE SURFACE FRONTAL BOUNDARY REMAINING
STALLED IN THE VICINITY OF THE FORECAST AREA THROUGH THE END OF
THE WEEK. EXPECT DAYTIME HIGHS MAINLY IN THE 80S WITH LOWS MAINLY
IN THE 50S THROUGH THIS PERIOD.
SOMEWHAT COOLER TEMPERATURES ARE EXPECTED ON FRIDAY AND SATURDAY
WITH DRY CONDITIONS SATURDAY AND SUNDAY IN THE WAKE OF THE
STRONGER SHORT WAVE TROUGH ALOFT AND THE HIGH PRESSURE AREA TO
FOLLOW A COLD FRONT ACROSS THE REGION. SURFACE HIGH PRESSURE MOVES
OUT OF THE FORECAST ARE ON SUNDAY WITH THE LEE TROUGH DEVELOPING
AND TEMPERATURES WARMING AGAIN WITH SOUTHWEST SURFACE FLOW AND THE
WEAKENING RIDGE ALOFT OVER SOUTHWEST U.S. EXTENDING INTO THE
CENTRAL HIGH PLAINS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1145 AM MDT MON SEP 7 2015
LOW STRATUS/CIGS SHOULD INCREASE TO VFR BY THE MIDDLE OF THE
AFTERNOON AT BOTH KGLD AND KMCK. VIS SATELLITE ALREADY SHOWING
BACK EDGE OF STRATUS JUST SW OF KGLD AND THIS SHOULD CONTINUE TO
THE NORTHEAST AS INDICATED BY SHORT RANGE GUIDANCE LOW LEVEL
MOISTURE FIELDS. SHOWERS/THUNDERSTORMS ARE STILL POSSIBLE ACROSS
THE AREA THIS AFTERNOON/EVENING WITH FRONT LINGERING JUST SOUTH OF
KGLD AND ADDITIONAL UPPER LEVEL DISTURBANCES EXPECTED TO MOVE
THROUGH REGION. HIGH RES GUIDANCE SHOWING A LULL IN ACTIVITY THIS
AFTERNOON WITH ACTIVITY INCREASING IN COVERAGE THIS EVENING. AT
THIS POINT CONFIDENCE WAS TOO LOW TO INCLUDE MENTION OF THUNDER
IN TAFS BUT I DID KEEP VCSH IN PLACE.
GUIDANCE SHOWING LOW STRATUS/FOG REDEVELOPING WITH LIGHT
EAST/NORTHEAST FLOW OVER CENTRAL NEBRASKA AND ADVECTING TO THE
SOUTHWEST OVER KMCK THEN KGLD...LINGERING THROUGH MID MORNING.
THERE MAY BE A PERIOD OF LIFR VIS/CIG...HOWEVER CONFIDENCE IN
PREVAILING CONDITIONS IS LEANING TOWARDS IFR VIS (1-2SM)BASED ON
MODEL CONSENSUS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...LOCKHART
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
144 PM MDT MON SEP 7 2015
.SHORT TERM...(THIS AFTERNOON THROUGH TUESDAY)
ISSUED AT 143 PM MDT MON SEP 7 2015
EARLY AFTERNOON WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOWS SW
FLOW IN PLACE ACROSS CENTRAL ROCKIES OVER OUR CWA...AND INTO THE
NORTHERN PLAINS. THIS IS AHEAD OF LARGE UPPER LOW CENTERED OVER
CENTRAL CANADA WITH BROAD TROUGHING EXTENDING SOUTH ACROSS THE
PACIFIC NORTHWEST. CHECKING DYNAMIC TROPOPAUSE...EMBEDDED WEAK
SHORTWAVE TROUGH THAT ROTATED THROUGH REGION THIS MORNING IS NOW
OVER NORTHCENTRAL KS WITH A STRONGER PV HEIGHT ANOMALY ENTERING
CENTRAL COLORADO. SUBSIDENCE BEHIND THE INITIAL FEATURE IS STILL
TRANSITIONING ACROSS MOSTLY OF OUR CWA. AT THE SURFACE A STALLED
FRONT IS JUST SOUTH OF INTERSTATE 70 WITH SURFACE LOW EXTENDING
FROM SOUTHERN COLORADO ACROSS SW KS AND INTO NW KANSAS.
THIS AFTERNOON-TUESDAY...FORCING IS EXPECTED TO INCREASE THIS
EVENING WITH NEXT SHORTWAVE TROUGH MOVING OUT OF THE CENTRAL ROCKIES
AND INTERACTING WITH STALLED FRONTAL ZONE OVER OUR CWA. THERE IS
THE POSSIBILITY FOR OVERRUNNING/BACKBUILDING ALONG ELEVATED FRONTAL
ZONE/STRENGTHENING H7 TROUGH AXIS AS THIS FEATURE MOVES ACROSS THE
REGION. EAST/NORTHEAST FLOW WILL CONTINUE TO ADVECTS BOUNTIFUL
MOISTURE OVER OUR CWA...WITH MODERATE INSTABILITY CONTINUING
THROUGH THE EVENING. CONFIDENCE IS LOWER REGARDING COVERAGE...WITH
FAIRLY LARGE SPREAD IN GUIDANCE SINCE OVERNIGHT AND SUBSIDENCE
INITIALLY IN PLACE OVER OUR CWA. CURRENT ARW/NMM DEPICTS ACTIVITY
INITIATING WEST OF OUR CWA...OR OVER OUR WESTERN CWA AROUND 00Z AND
TRACKING ALONG/NORTH OF FRONT THIS EVENING/OVERNIGHT BEFORE SLOWLY
TRANSITIONING EAST. HRRR/RAP BOTH SUPPORT A SIMILAR LOCATION AND
TIMING...HOWEVER SHOW MUCH LESS IN THE WAY OF COVERAGE. I FELT
COMFORTABLE ADJUSTING THE TIMING TO FAVOR THIS EVENING FOR BEST
COVERAGE AND KEPT MENTION LIMITED TO CHANCE FOR NOW. GUIDANCE SHOWS
BAROCLINIC ZONE LINGERING THROUGH EARLY AFTERNOON TUESDAY ACROSS OUR
SOUTHEAST WITH ADDITIONAL SHOWER/THUNDERSTORM DEVELOPMENT POSSIBLE.
I SHOWED GRADUAL TRANSITION TO THE EAST/SOUTHEAST IN LINE WITH
MODEL CONSENSUS.
REGARDING SEVERE THREAT...HIGH LOW LEVEL MIXING RATIOS HAVE AIDED IN
MODERATE INSTABILITY BUILDING ACROSS OUR CWA WITH ML CAPE 1500-2500
J/KG DEPICTED ON RAP ANALYSIS. DEEP UNIDIRECTIONAL FLOW HAS LED TO
HIGH SHEAR IN MID TO UPPER LEVELS WITH EFFECTIVE SHEER VALUES
ALREADY IN EXCESS OF 50KT OVER OUR CWA. BEST LOW LEVEL SHEAR IS
OVER NORTH CENTRAL KS/NEAR HILL CITY ASSOCIATED WITH VEERING NEAR
WHERE CLOSED SURFACE LOW MAY BE DEVELOPING BASED ON WIND/PRESSURE
FIELD. SEVERE THREAT SHOULD PREDOMINANTLY BE CONFINED TO LARGE
HAIL/DAMAGING WINDS...HOWEVER LOCATIONS IN THE FAR EASTERN PART OF
OUR CWA COULD SEE FAVORABLE CONDITIONS FOR SUPERCELL DEVELOPMENT
AND TORNADO RISK. WINDOW FOR THIS SHOULD BE CONFINED TO THIS
AFTERNOON/EARLY EVENING WITH FRONT TRANSITIONING BACK TO THE
SOUTHEAST THIS EVENING.
RAP/HRRR/NAM/SREF CONTINUE TO SHOW STRATUS/FOG REDEVELOPING ACROSS
NEBRASKA AND ADVECTING/SPREADING SOUTHWEST ACROSS OUR CWA. LOWEST
VIS COULD APPROACH DENSE FOG ADVISORY CRITERIA...THOUGH IT DOES
APPEAR TO BE FAIRLY TRANSIENT REGARDING LOWEST VISIBILITIES. FOR NOW
I KEPT AREAS OF FOG MENTION...AND WILL ALLOW SUBSEQUENT SHIFTS TO
MONITOR NEED FOR NEW DENSE FOG ADVISORY.
.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 240 AM MDT MON SEP 7 2015
FOR THE MAJORITY OF THE LONG TERM...THURSDAY 12Z THROUGH SATURDAY
12Z...THE UPPER LEVEL FLOW IS FAIRLY SIMILAR IN THE GFS AND
EUROPEAN. THERE IS A TROUGH STRETCHING OVER THE GREAT LAKES REGION
AND DOWN INTO THE SOUTHEASTERN STATES...WITH HIGH PRESSURE SITTING
OVER THE WESTERN AND SOUTHWESTERN STATES. AFTER 12Z ON SATURDAY THE
MODELS START TO DIFFER ON HOW THEY HANDLE THE TROUGH IN THE EASTERN
HALF OF THE US. THE GFS STARTS TO PUSH THE TROUGH OUT WHEREAS THE
EUROPEAN HAS THAT TROUGH BECOMING MUCH STRONGER...WITH A CLOSED LOW
AND KEEPS THE TROUGH OVER THE EASTERN REGION. THIS IS SOMETHING TO
KEEP AN EYE ON AS WE GET CLOSER TO THIS COMING WEEKEND.
AS FAR AS PRECIPITATION CHANCES...THURSDAY HAS SOME SLIGHT CHANCES
FOR STORMS OVER THE SOUTHERN AND EASTERN PORTIONS OF THE CWA IN THE
AFTERNOON INTO THE EVENING. GREATER PRECIP CHANCES WILL OCCUR IN THE
EVENING HOURS. SURFACE CAPES ARE SHOWING TO REACH UP TO 2000
J/KG...THE EUROPEAN HAS THE HIGHER CAPE VALUES BUT THE GFS STILL
SHOWS SOME FAIRLY SIGNIFICANT VALUES. BULK SHEAR IS NOT IMPRESSIVE.
FRIDAY HAS THE GREATEST POTENTIAL FOR PRECIPITATION DURING THE
PERIOD. THERE ARE SOME SLIGHT CHANCE POPS FRIDAY AFTERNOON BUT STORM
CHANCES INCREASE FRIDAY EVENING INTO THE OVERNIGHT HOURS. THIS IS
DUE TO A 700MB SHORTWAVE MOVING THROUGH THE CWA IN THE GFS AT 18Z
FRIDAY INTO 06Z SATURDAY...IN ADDITION TO SURFACE CAPE VALUES AROUND
1900 J/KG AND BULK SHEAR REACHING UP TO 50 KTS. THESE STORMS WILL
MOVE OUT FAIRLY QUICK. THE EUROPEAN DOES NOT SHOW THIS SAME
PATTERN...THIS IS LIKELY DUE TO IT STRENGTHENING THE TROUGH IN THE
EASTERN US. THIS IS DEFINITELY SOMETHING TO KEEP AN EYE ON. AS OF
RIGHT NOW...SLIGHT CHANCE AND CHANCE POPS ARE BEING FORECASTED.
SATURDAY AND SUNDAY WILL DRY OUT. THE GFS HAS THE HIGH PRESSURE
STILL DOMINATING IN THE WESTERN STATES AND ZONAL UPPER LEVEL FLOW
STARTING TO FORM OVER THE NORTHWEST. THE EUROPEAN UPPER LEVEL FLOW
IS DIFFERENT BUT STILL SHOWS DRY CONDITIONS. HIGH TEMPERATURES WILL
BE IN THE LOW TO MID 80S EACH DAY. A POSSIBLE SLIGHT TEMPERATURE
DECREASE FRIDAY...IN THE HIGH 70S OVER SOME AREAS...DUE TO THE
PRECIP MOVING INTO THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1145 AM MDT MON SEP 7 2015
LOW STRATUS/CIGS SHOULD INCREASE TO VFR BY THE MIDDLE OF THE
AFTERNOON AT BOTH KGLD AND KMCK. VIS SATELLITE ALREADY SHOWING
BACK EDGE OF STRATUS JUST SW OF KGLD AND THIS SHOULD CONTINUE TO
THE NORTHEAST AS INDICATED BY SHORT RANGE GUIDANCE LOW LEVEL
MOISTURE FIELDS. SHOWERS/THUNDERSTORMS ARE STILL POSSIBLE ACROSS
THE AREA THIS AFTERNOON/EVENING WITH FRONT LINGERING JUST SOUTH OF
KGLD AND ADDITIONAL UPPER LEVEL DISTURBANCES EXPECTED TO MOVE
THROUGH REGION. HIGH RES GUIDANCE SHOWING A LULL IN ACTIVITY THIS
AFTERNOON WITH ACTIVITY INCREASING IN COVERAGE THIS EVENING. AT
THIS POINT CONFIDENCE WAS TOO LOW TO INCLUDE MENTION OF THUNDER
IN TAFS BUT I DID KEEP VCSH IN PLACE.
GUIDANCE SHOWING LOW STRATUS/FOG REDEVELOPING WITH LIGHT
EAST/NORTHEAST FLOW OVER CENTRAL NEBRASKA AND ADVECTING TO THE
SOUTHWEST OVER KMCK THEN KGLD...LINGERING THROUGH MID MORNING.
THERE MAY BE A PERIOD OF LIFR VIS/CIG...HOWEVER CONFIDENCE IN
PREVAILING CONDITIONS IS LEANING TOWARDS IFR VIS (1-2SM)BASED ON
MODEL CONSENSUS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...CLT
AVIATION...DR
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1155 PM CDT SUN SEP 6 2015
...Update to aviation forecast discussion...
.UPDATE...
ISSUED AT 933 PM CDT SUN SEP 6 2015
Convective development in the local forecast area continues to
struggle, but a rather strong model signal continues to indicate
that elevated storms (similar to that currently seen in far
southeast Nebraska) will develop into eastern KS as well tonight.
It seems that for this to occur depends on the development of a
cold pool from the ongoing storms. This currently exists near the
Nebraska border, and if it can continue to be reinforced and
pushed south than would expect at least scattered storms to
develop overnight. If this happens, the severe weather threat is
quite low but non-zero for wind/hail. Pockets of heavy rain also
remain possible if these storms develop as there could be
localized training, but dry ground conditions suggest the flash
flood potential is quite low.
&&
.SHORT TERM...(THIS EVENING THROUGH Monday)
ISSUED AT 254 PM CDT SUN SEP 6 2015
Latest surface analysis had the frontal boundary from just east of
Albion Nebraska to near Norton Kansas at 19Z. Surface temperatures
ahead of the front across northeast Kansas have warmed to near the
century mark in north central and northeast Kansas. Latest
mesoanalysis along with latest RAP soundings show steep low level
lapse rates and SBCAPE around 3000 J/kg this afternoon. Hires
short term models have differing scenarios with regards to
convective development, with the operational HRRR and the RAP the
most robust with developing storms where the ARW, NMM and
experimental HRRR showing less coverage across central and north
central Kansas tonight. However most models continue to show a
signal of a MCS developing across far northeast Kansas into
southwest Iowa and northwest Missouri tonight and then moving it
south southeast across eastern Kansas and western Missouri. The
aforementioned frontal boundary will gradually move eastward
tonight into the forecast area. Not sure exactly how far south the
boundary will move tonight before lifting north again on Labor
Day. Water vapor loop this afternoon shows moisture streaming from
the eastern Pacific into the Central Plains. Southwesterly low
level jet will advect high theta-e air into northeast Kansas
overnight and should help to maintain the forward propagating MCS
as well as contribute to high precipitation efficiency. On Labor
day the front is expected to lift northward in response to an
upper level trough moving eastward into the Northern and Central
Plains to near or just north of the Nebraska and Kansas border in
the afternoon. Left over boundaries from morning convection may
focus isolated convection in the afternoon, but feel most areas
will be dry until late afternoon along the Kansas and Nebraska
border near the front. Effective shear tonight and Labor Day will
be around 25 to 30 kts along with ample instability. If storms
develop late this afternoon and early evening they will have the
potential for damaging wind gusts and also again on Labor Day
afternoon. There is also some potential for Hail as storms become
elevated later tonight, but locally heavy rainfall will be the
main concern. Lows tonight remain mild in the low to mid 70s and
highs on Labor Day will be dependent on cloud cover. Feel there
may be enough sunshine to send temps back into the lower 90s for
most areas.
.LONG TERM...(Monday NIGHT THROUGH Sunday)
ISSUED AT 254 PM CDT SUN SEP 6 2015
Monday night through Wednesday...Synoptic scale boundary should
extend from southeast Nebraska through north central KS by early
Monday evening. As boundary sags slowly south over night, expect
clusters of thunderstorms to develop along it and move east, with
the best chance for heavier rainfall north of I70, and especially
near and north of U.S. 36. Have highest POPs and most QPF for that
area. On Tuesday, most short term models bring frontal boundary
nearly through the forecast area, although outflow from
thunderstorm complex makes it somewhat hard to place. Highest POPs
should shift from northeast KS into far eastern, and especially
east central KS during the afternoon. Thunderstorm activity near
the front should shift out of east central KS during the evening.
Would expect late Tuesday night and Wednesday to be dry as a ridge
of surface high pressure builds in.
Wednesday night through Sunday...Eastern KS remains in northwest
flow aloft through Saturday. While gulf airmass should remain to
our south, periodic disturbances in this northwest flow will
result in chances for showers and thunderstorms. Cooler, more
stable airmass over far northeast KS is expected to keep the
best chance for convective activity over north central and parts
of east central KS. Much cooler temperatures than we`ve had
recently are expected for the latter part of the week into the
weekend, with highs in the 70s to lower 80s, depending on how much
sun is seen each afternoon.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z Monday NIGHT)
ISSUED AT 1152 PM CDT SUN SEP 6 2015
Another rather uncertain TAF concerning convective potential. Have
maintained periods of VCTS to highlight the most likely timing of
TS near TAF sites, but have not gone with prevailing TS as
coverage is not likely to be widespread and confidence in
development is on the lower end. Outside of thunderstorms, VFR
conditions are likely through the TAF period.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Barjenbruch
SHORT TERM...53
LONG TERM...GDP
AVIATION...Barjenbruch
AREA FORECAST DISCUSSION
NWS JACKSON KY
132 PM EDT MON SEP 7 2015
.UPDATE...
ISSUED AT 1248 PM EDT MON SEP 7 2015
HOURLY TEMPERATURES ACROSS THE AREA HAVE BEEN RUNNING SEVERAL
DEGREES WARMER SO FAR TODAY THAN THE PREVIOUS FORECAST WAS
DEPICTING. BASED ON THAT AND THE DELAY IN CLOUD FORMATION TODAY
COMPARED TO YESTERDAY...DECIDED TO GO AHEAD AND INCREASE
TEMPERATURES FOR MOST LOCATIONS ACROSS EASTERN KENTUCKY BY A
COUPLE OF DEGREES. ALSO REMOVED OUTDATED WORDING FROM THE ZONE
FORECAST TEXT PRODUCT.
UPDATE ISSUED AT 1015 AM EDT MON SEP 7 2015
UPDATED THE FORECAST TO REMOVE MENTION OF FOG FROM THE TODAY
PERIOD. ALSO UPDATED THE HOURLY GRIDS WITH THE LATEST OBS DATA TO
ESTABLISH NEW TRENDS. WILL NEED TO ISSUE ANOTHER UPDATE IN A
COUPLE OF HOURS TO REMOVE WHAT WILL THEN BE OUTDATED AFTERNOON
WORDING AND ANY OTHER NECESSARY CHANGES.
UPDATE ISSUED AT 730 AM EDT MON SEP 7 2015
HOURLY GRIDS HAVE BEEN UPDATED BASED ON RECENT
OBSERVATIONS...TRENDING DOWN A DEGREE OR TWO IN A FEW VALLEY
LOCATIONS. SFC HIGH PRESSURE WILL BRING MOSTLY DRY WEATHER TO
MUCH OF THE REGION TODAY. VALLEY FOG...DENSE IN SOME
LOCATIONS...WILL DISSIPATE BY AROUND 930 AM. CUMULUS SHOULD BEGIN
TO FORM AROUND NOON AND ISOLATED CONVECTION CANNOT BE RULED OUT.
NEAR TERM MODELS SUCH AS SEVERAL RECENT HRRR RUNS DEVELOP SOME
ISOLATED CONVECTION AROUND 1 PM...MAINLY NEAR THE TN AND VA BORDER
AND ACROSS THE WESTERN PART OF THE CWA. THIS IS IN LINE WITH THE
PREVIOUS FORECAST...SO NO CHANGES WERE MADE WITH THESE.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 350 AM EDT MON SEP 7 2015
THE REGION REMAINS DOMINATED A RIDGE HIGH PRESSURE IN THE LOWER
LEVELS THAT EXTENDS FROM THE OH VALLEY INTO THE ATLANTIC...ALTHOUGH
AT MID LEVELS THE AREA CONTINUES TO RESIDE IN A WEAKNESS BETWEEN
TWO RIDGE CENTERS ONE OVER THE ATLANTIC AND ANOTHER CENTERED OVER
THE SOUTHERN PLAINS. TO THE SOUTH OF THE AREA...A WEAK UPPER LEVEL
RIDGE REMAINS. SKIES HAVE REMAINED CLEAR TO MOSTLY CLEAR OVERNIGHT
AND VALLEY FOG HAS AGAIN FORMED. IT IS LIKELY DENSE NEAR SOME OF
THE AREA RIVERS...OF SHOULD BECOME DENSE PRIOR TO DAWN.
VERY LITTLE CHANCE IS EXPECTED IN THE UPPER PATTERN IS EXPECTED
TODAY ALTHOUGH THE WEAK UPPER LEVEL LOW OVER THE SOUTHEAST SHOULD
DRIFT SOUTHWEST. SOME OF THE MODELS HAVE HEIGHTS RISING A BIT
NORTH OF THE REGION. THE SHORT TERM MODELS GENERATE SOME CONVECTION
ACROSS THE CENTRAL TO WESTERN PARTS OF THE CWA AND NEAR THE VA AND
TN BORDERS IN SOME CASES FROM AROUND MIDDAY INTO THE AFTERNOON.
SSEO CONVECTIVE PROBABILITIES REACH THE 40 TO 60 PERCENT RANGE
ACROSS THE SOUTH AND SOUTHWESTERN PARTS OF THE CWA WITH THIS AREA
EXTENDING NORTH INTO CENTRAL KY FOR THIS AFTERNOON. GIVEN THAT
THIS HAS BEEN A GOOD PREDICTOR OF AREAS OF CONVECTION THE PAST
COUPLE OF DAYS...HAVE OPTED TO GO WITH A SLIGHT CHANCE POP IN THE
AREAS THAT IT HIGHLIGHTS WITH THESE HIGHER PROBABILITIES. WARM MID
LEVEL TEMPS SHOULD LARGELY CAP CONVECTION OVER MOST OF THE
AREA...AND THE VAST MAJORITY OF THE REGION SHOULD REMAIN DRY.
TEMPERATURES SHOULD AGAIN BE ABOVE NORMAL...IN THE UPPER 80S TO
AROUND 90 RANGE OUTSIDE OF THE HIGHEST TERRAIN.
THIS EVENING THROUGH TUESDAY...SFC HIGH PRESSURE SHOULD DOMINATE
AND BE CENTERED TO THE EAST OF THE AREA. HOWEVER...THE MID AND AND
UPPER LEVEL PATTERN SHOULD BEGIN TO CHANGE. THE WEAK UPPER LOW
OVER THE SOUTHEAST SHOULD CONTINUE MEANDERING TO THE SOUTHWEST
WHILE AN UPPER LEVEL LOW MOVES FROM SASKATCHEWAN INTO MANITOBA.
TO THE SOUTH...THE UPPER LEVEL RIDGE INITIALLY CENTERED OVER THE
SOUTHERN PLAINS SHOULD BECOME CENTERED OVER THE RIO GRANDE
VALLEY/NORTHERN MEXICO WHILE A FEW SHORTWAVES MOVING AROUND THIS
RIDGE TRACK FROM THE ROCKIES AND INTO THE PLAINS. THIS WILL LEAD
TO THE BEGINNING OF HEIGHT FALLS OVER THE MID MS VALLEY NORTH INTO
THE WESTERN GREAT LAKES. THIS WILL ALLOW A FRONTAL ZONE TO MOVE
DROP SOUTHEAST INTO THE ST LAWRENCE VALLEY TO CENTRAL GREAT LAKES
TO CENTRAL PLAINS.
ON TUESDAY...THE UPPER LEVEL LOW OVER CANADA SHOULD CONTINUE
TRACKING TO THE EAST NORTHEAST WITH HEIGHTS FALLING OVER THE LOWER
OH VALLEY AS SHORTWAVES MOVE FROM THE PLAINS TOWARD THE GREAT
LAKES. AT THAT POINT...THE UPPER LOW OVER THE GULF OF MEXICO AND
SOUTHEAST SHOULD BEGIN TO MERGE WITH THE TROUGH TO THE NORTH. THE
DEEPEST MOISTURE SHOULD REMAIN TO THE SOUTH OF THE AREA...WITH THE
SOUTHERN AND SOUTHEASTERN FRINGE OF THE AREA THE MOSTLY LIKELY
AREA FOR ANY CONVECTION TO FORM. GREAT CHANCES FOR CONVECTION WILL
HOLD OFF UNTIL THE LONG TERM PERIOD.
AS ALREADY NOTED...SLIGHT CHANCE POPS WERE USED ACROSS THE FAR
WEST AND SOUTH FOR TODAY. ANY CONVECTION AND CU SHOULD DISSIPATE
DURING THE EVENING...WITH DRY WEATHER ALONG WITH SOME PATCHY DENSE
RIVER VALLEY FOG AGAIN POSSIBLE TONIGHT. THIS FOG SHOULD DISSIPATE
WITHIN AN COUPLE OF HOURS AFTER SUNRISE ON TUESDAY. SLIGHT CHANCE
POPS WERE AGAIN USED ACROSS THE FAR SOUTH AND ALONG THE VA BORDER
ON TUESDAY AS DAYTIME HEATING COULD LEAD TO CONVECTION DEVELOPING
ACROSS THAT AREA. IN SUMMARY...BOTH DAYS ARE EXPECTED TO REMAIN
DRY FOR THE VAST MAJORITY OF THE REGION.
ABOVE NORMAL TEMPERATURES SHOULD PERSIST THOUGH THE PERIOD WITH A
MINOR RIDGE/VALLEY SPLIT FOR TONIGHT.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 407 AM EDT MON SEP 7 2015
THE GENERALLY DRY PATTERN AND WARM TEMPERATURES WILL FINALLY COME
TO A END.
THE PERIOD WILL BE MET WITH RIDGING FINALLY BREAKING DOWN ACROSS
THE EAST...AS A TROUGH BEGINS TO APPROACH FROM THE MIDWEST. THAT
SAID MODELS OVERALL IN GOOD AGREEMENT THROUGH MUCH OF THE FIRST
HALF OF THE PERIOD IN TERMS OF UPPER LEVELS. HOWEVER TOWARD THE
END THE AMPLITUDE/STRENGTH OF THE TROUGH COMES INTO
QUESTION...WITH THE 07/00Z ECMWF SHOWING A CUT OFF CENTERED ACROSS
THE GREAT LAKES BY SATURDAY. RIGHT NOW CONFIDENCE REMAINS LOWER
OVERALL ON THIS GIVEN THIS IS THE FIRST RUN TO BE STRENGTHENING
THE 500MB LOW TO THAT EXTENT...AND NONE OF THE OTHER LONG RANGE
MODEL OPERATIONAL RUNS ARE IN LINE WITH THIS THOUGHT. THOUGH MIGHT
BE WORTH NOTING A FEW OF THE ENSEMBLE PERTURBATIONS SEEM TO BE
PAINTING SOMETHING SIMILAR.
AT THE SURFACE THIS PERIOD WILL BE MET WITH BETTER CHANCES OF
WIDESPREAD PRECIP AS COLD FRONT APPROACHES AND MOVES THROUGH THE
REGION. BEST CHANCES RIGHT NOW LOOK TO BE WED AND THU...WITH BEST
UPPER LEVEL SUPPORT BOTH DAYS. MORE UNCERTAINTY EXISTS WITH
SECONDARY COLD FRONT TOWARD THE END OF THE OF THE PERIOD. OVERALL
LOOKS LIKE THIS WILL BE A DRIER FRONT...BUT AFOREMENTIONED CLOSED
LOW ADVERTISED BY THE ECMWF WOULD BRING BETTER CHANCES OF PRECIP
SATURDAY. RIGHT NOW STUCK CLOSER TO THE BLEND GIVEN THE MORE
UNCERTAIN PATTERN.
THE TEMPERATURES WILL CERTAINLY BE WELCOMED WITH HIGHS NEAR TO
BELOW NORMAL. WE WILL ALSO SEE A SOME 50S FOR LOWS BY THE UPCOMING
WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 132 PM EDT MON SEP 7 2015
A RIDGE OF HIGH PRESSURE WILL CONTINUE TO INFLUENCE THE WEATHER OF
EASTERN KENTUCKY DURING THE TAF PERIOD. SCATTERED TO BROKEN LOW
LEVEL CUMULUS CLOUDS WILL PERSIST THROUGH THE REMAINDER OF THE
DAY LIGHT HOURS...BEFORE DISSIPATING QUICKLY AFTER THE SUN GOES
DOWN. ISOLATED SHOWERS AND STORMS ALONG AND WEST OF I-75 THIS
AFTERNOON AND EVENING. SHOWERS AND STORMS WILL BE POSSIBLE ALONG
THE TENNESSEE AND SOUTHWESTERN VIRGINIA BORDERS. THE ISOLATED
NATURE OF THE PRECIPITATION SHOULD KEEP IT OUT OF THE TAF SITES
AND LOZ AND SME. JKL...SYM...AND SJS SHOULD EXPERIENCE ONLY PARTLY
CLOUDY SKIES THROUGH LATE THIS AFTERNOON. WITH CONDITIONS A BIT
WARMER AND DRIER THAN YESTERDAY...FOG SHOULD BE A LITTLE BIT LESS
WIDESPREAD OVERNIGHT. LOZ AND SME MAY STILL SEE SOME FOG DUE TO
ANY RAINFALL THAT OCCURS TODAY WHICH COULD RESULT IN MVFR TO IFR
CONDITIONS AT TIMES LATE TONIGHT. LOZ MAY EVEN SEE BRIEF PERIODS
OF LIFR CIGS AS THE VALLEY FLOOR SATURATES. ASIDE FROM THAT...ANY
FOG SHOULD BE CONFINED TO VALLEYS AND NEAR BODIES OF WATER. WINDS
DURING THE PERIOD WILL BE LIGHT AND VARIABLE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR
SHORT TERM...JP
LONG TERM...DJ
AVIATION...AR
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
105 PM EDT MON SEP 7 2015
...UPDATED AVIATION DISCUSSION...
...FORECAST UPDATE...
ISSUED AT 1130 AM EDT MON SEP 7 2015
THE FORECAST IS ON TRACK FOR THIS AFTERNOON...WITH MAX TEMPS
EXPECTED TO HIT THE LOW TO MID 90S. COMPARED TO 24 HOURS
AGO...READINGS ARE ABOUT 1 TO 2 DEGREES WARMER SO FEEL CONFIDENT
WE`LL HIT THE FORECAST HIGHS.
WITH WEAK SHEAR AXIS OVERHEAD...AND WEAK SHORTWAVE RETROGRADING BACK
INTO SOUTHEAST KENTUCKY...THE SLIGHT CHANCES OF SHOWERS/STORMS LOOK
GOOD. RAP SOUNDINGS ARE SHOWING WARMER MID LEVEL TEMPERATURES
COMPARED TO THE PAST FEW DAYS...WHICH SHOULD KEEP COVERAGE/INTENSITY
TO A MINIMUM.
.SHORT TERM (NOW THROUGH TUESDAY)...
ISSUED AT 235 AM EDT MON SEP 7 2015
THE SYNOPTIC PATTERN EARLY THIS MORNING FEATURES A BROAD RIDGE
ACROSS MUCH OF THE EASTERN CONUS...WITH A VERY BROAD/WEAK LOW
CONTINUING TO SPIN BENEATH THE RIDGE OVER NORTHERN GEORGIA. A SHEAR
AXIS NOTED ON THE NORTHWEST SIDE OF THIS LOW WILL BE THE MAIN FOCUS
TODAY.
LOOKING BACK TO THE CONVECTION YESTERDAY...IT WAS ALL SPARKED WITHIN
THE SHEAR AXIS BETWEEN THE UPPER LOW TO THE SOUTHEAST AND THE
AMPLIFIED RIDGE ACROSS THE GREAT LAKES/MIDWEST REGION. AREAS MAINLY
EAST OF I-65 WILL ONCE AGAIN BE WITHIN THIS SHEAR AXIS TODAY THROUGH
WHICH VERY SUBTLE UPPER-LEVEL WAVES WILL TRAVERSE AS THEY ROTATE
AROUND THE UPPER LOW. FORECAST SOUNDINGS DO SHOW WARM AIR ALOFT
MAINLY AROUND 650-700MB...BUT IT IS NOT ALL THAT MUCH STRONGER THAN
YESTERDAY WHERE WE HAD SOME ISOLATED/WIDELY SCATTERED CONVECTION.
MANY OF THE CAMS ARE ON BOARD WITH THE IDEA OF SOME VERY ISOLATED
ACTIVITY TODAY AND THESE HAVE BEEN LEADING THE CHARGE WITH
CONVECTIVE COVERAGE THE PAST FEW DAYS. THEREFORE...WILL GO WITH 15-
20% COVERAGE WITH THE BEST CHANCES EAST OF I-65 AND SOUTH OF I-64.
LOW-LEVEL THICKNESSES REMAIN VERY SIMILIAR TO WHAT THEY`VE BEEN THE
PAST FEW DAYS...SO BARRING ANY ENHANCED CLOUD COVER FROM
CONVECTION...HIGHS FIRMLY INTO THE 90S LOOK LIKELY AGAIN TODAY.
TONIGHT WILL BE MAINLY CLEAR AND MILD...WITH LOWS IN THE MID 60S TO
LOWER 70S ONCE AGAIN. ON TUESDAY...THE UPPER LOW WILL BECOME LESS
OF A PLAYER AS IT MOVES OFF TO THE SOUTHWEST. ADDITIONALLY...THE
CAPPING TOMORROW LOOKS SUBSTANTIALLY STRONGER THAN IT DOES TODAY.
THEREFORE...WILL GO WITH A DRY FORECAST AND A PERSISTENCE FORECAST
FOR HIGH TEMPERATURES.
.LONG TERM (TUESDAY NIGHT THROUGH SUNDAY)...
ISSUED AT 305 AM EDT MON SEP 7 2015
STILL LOOKING AT A TROUGH MOVING ACROSS THE REGION
WEDNESDAY/WEDNESDAY NIGHT. THE QUESTION IS HOW MUCH PRECIPITATION
WILL MOVE INTO THE REGION WEDNESDAY MORNING AHEAD OF IT. LOOKS LIKE
SOME STORMS WILL FORM OVER MO/IL EARLY WEDNESDAY AND THESE MAY PUSH
INTO OUR NORTHWEST COUNTIES AROUND DAYBREAK. THEY COULD BRING
CLOUDINESS THROUGH THE DAY...DELAYING THE ONSET OF NEW AFTERNOON
STORMS UNTIL LATER IN THE DAY AND BRINGING TEMPERATURES DOWN. SHOULD
THESE STORMS DIE OFF QUICKER THAN IN THIS FORECAST...THEN WE WOULD
SEE A LITTLE WARMER AFTERNOON HIGHS AND AN EARLIER ONSET OF STORM
DEVELOPMENT. FOR NOW WILL CALL FOR AFTERNOON HIGHS IN THE
80S...BREAKING OUR 90+ DEGREE STRING TO START SEPTEMBER. AS FOR
SEVERITY OF THESE STORMS...MODEL WIND FIELDS ARE NOT OVERLY
IMPRESSIVE. THINK THE STRONGER GUSTS WOULD COME WITH THE LATTER
SCENARIO GIVEN ABOVE. WILL CONTINUE TO MENTION BRIEF GUSTY WINDS IN
THE HWO.
ANOTHER WEAKER SHORTWAVE LOOKS TO MOVE THROUGH THE REGION
THURSDAY...CONTINUING THE CHANCE FOR RAIN...WITH THE BEST CHANCE IN
OUR SOUTHEAST. FRIDAY CONTINUES TO TREND DRIER...BUT WITH ANOTHER
WAVE CROSS ING THE REGION CANNOT RULE OUT SOME DEVELOPMENT AT LEAST
EAST OF I-65. AFTER THAT WE SHOULD BE TOO DRY FOR FURTHER
DEVELOPMENT THIS WEEKEND...AND TEMPERATURES WILL BE QUITE
PLEASANT...WITH HIGHS IN THE 70S SATURDAY AND AROUND 80 SUNDAY.
&&
.AVIATION (18Z TAF UPDATE)...
ISSUED AT 105 PM EDT MON SEP 7 2015
PLAN ON VFR CONDITIONS THE REMAINDER OF TODAY AT ALL TAF SITES AS
HIGH PRESSURE AT THE SURFACE AND ALOFT PROVIDES HOT AND DRY
CONDITIONS TO THE AREA. WINDS WILL BE LIGHT/VARIABLE.
FOG WILL ONCE AGAIN BE A THREAT OVERNIGHT...PARTICULARLY AT BWG
WHERE MVFR RESTRICTIONS ARE EXPECTED. LOWER CONDITIONS WILL BE
POSSIBLE IF ISOLATED TO SCATTERED STORMS DEVELOP NEAR THE
TERMINAL...OTHERWISE THINK THAT A DAY OF DRYING SHOULD KEEP
VISIBILITY FROM DROPPING TOO FAR.
FOR TUESDAY...PLAN ON ONE MORE DRY AND HOT DAY FOR THE REGION BEFORE
A PATTERN CHANGE AND SHOWERS/STORMS RETURN MID-WEEK.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
UPDATE.........ZBT
SHORT TERM.....KJD
LONG TERM......RJS
AVIATION.......ZBT
AREA FORECAST DISCUSSION
NWS JACKSON KY
1249 PM EDT MON SEP 7 2015
.UPDATE...
ISSUED AT 1248 PM EDT MON SEP 7 2015
HOURLY TEMPERATURES ACROSS THE AREA HAVE BEEN RUNNING SEVERAL
DEGREES WARMER SO FAR TODAY THAN THE PREVIOUS FORECAST WAS
DEPICTING. BASED ON THAT AND THE DELAY IN CLOUD FORMATION TODAY
COMPARED TO YESTERDAY...DECIDED TO GO AHEAD AND INCREASE
TEMPERATURES FOR MOST LOCATIONS ACROSS EASTERN KENTUCKY BY A
COUPLE OF DEGREES. ALSO REMOVED OUTDATED WORDING FROM THE ZONE
FORECAST TEXT PRODUCT.
UPDATE ISSUED AT 1015 AM EDT MON SEP 7 2015
UPDATED THE FORECAST TO REMOVE MENTION OF FOG FROM THE TODAY
PERIOD. ALSO UPDATED THE HOURLY GRIDS WITH THE LATEST OBS DATA TO
ESTABLISH NEW TRENDS. WILL NEED TO ISSUE ANOTHER UPDATE IN A
COUPLE OF HOURS TO REMOVE WHAT WILL THEN BE OUTDATED AFTERNOON
WORDING AND ANY OTHER NECESSARY CHANGES.
UPDATE ISSUED AT 730 AM EDT MON SEP 7 2015
HOURLY GRIDS HAVE BEEN UPDATED BASED ON RECENT
OBSERVATIONS...TRENDING DOWN A DEGREE OR TWO IN A FEW VALLEY
LOCATIONS. SFC HIGH PRESSURE WILL BRING MOSTLY DRY WEATHER TO
MUCH OF THE REGION TODAY. VALLEY FOG...DENSE IN SOME
LOCATIONS...WILL DISSIPATE BY AROUND 930 AM. CUMULUS SHOULD BEGIN
TO FORM AROUND NOON AND ISOLATED CONVECTION CANNOT BE RULED OUT.
NEAR TERM MODELS SUCH AS SEVERAL RECENT HRRR RUNS DEVELOP SOME
ISOLATED CONVECTION AROUND 1 PM...MAINLY NEAR THE TN AND VA BORDER
AND ACROSS THE WESTERN PART OF THE CWA. THIS IS IN LINE WITH THE
PREVIOUS FORECAST...SO NO CHANGES WERE MADE WITH THESE.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 350 AM EDT MON SEP 7 2015
THE REGION REMAINS DOMINATED A RIDGE HIGH PRESSURE IN THE LOWER
LEVELS THAT EXTENDS FROM THE OH VALLEY INTO THE ATLANTIC...ALTHOUGH
AT MID LEVELS THE AREA CONTINUES TO RESIDE IN A WEAKNESS BETWEEN
TWO RIDGE CENTERS ONE OVER THE ATLANTIC AND ANOTHER CENTERED OVER
THE SOUTHERN PLAINS. TO THE SOUTH OF THE AREA...A WEAK UPPER LEVEL
RIDGE REMAINS. SKIES HAVE REMAINED CLEAR TO MOSTLY CLEAR OVERNIGHT
AND VALLEY FOG HAS AGAIN FORMED. IT IS LIKELY DENSE NEAR SOME OF
THE AREA RIVERS...OF SHOULD BECOME DENSE PRIOR TO DAWN.
VERY LITTLE CHANCE IS EXPECTED IN THE UPPER PATTERN IS EXPECTED
TODAY ALTHOUGH THE WEAK UPPER LEVEL LOW OVER THE SOUTHEAST SHOULD
DRIFT SOUTHWEST. SOME OF THE MODELS HAVE HEIGHTS RISING A BIT
NORTH OF THE REGION. THE SHORT TERM MODELS GENERATE SOME CONVECTION
ACROSS THE CENTRAL TO WESTERN PARTS OF THE CWA AND NEAR THE VA AND
TN BORDERS IN SOME CASES FROM AROUND MIDDAY INTO THE AFTERNOON.
SSEO CONVECTIVE PROBABILITIES REACH THE 40 TO 60 PERCENT RANGE
ACROSS THE SOUTH AND SOUTHWESTERN PARTS OF THE CWA WITH THIS AREA
EXTENDING NORTH INTO CENTRAL KY FOR THIS AFTERNOON. GIVEN THAT
THIS HAS BEEN A GOOD PREDICTOR OF AREAS OF CONVECTION THE PAST
COUPLE OF DAYS...HAVE OPTED TO GO WITH A SLIGHT CHANCE POP IN THE
AREAS THAT IT HIGHLIGHTS WITH THESE HIGHER PROBABILITIES. WARM MID
LEVEL TEMPS SHOULD LARGELY CAP CONVECTION OVER MOST OF THE
AREA...AND THE VAST MAJORITY OF THE REGION SHOULD REMAIN DRY.
TEMPERATURES SHOULD AGAIN BE ABOVE NORMAL...IN THE UPPER 80S TO
AROUND 90 RANGE OUTSIDE OF THE HIGHEST TERRAIN.
THIS EVENING THROUGH TUESDAY...SFC HIGH PRESSURE SHOULD DOMINATE
AND BE CENTERED TO THE EAST OF THE AREA. HOWEVER...THE MID AND AND
UPPER LEVEL PATTERN SHOULD BEGIN TO CHANGE. THE WEAK UPPER LOW
OVER THE SOUTHEAST SHOULD CONTINUE MEANDERING TO THE SOUTHWEST
WHILE AN UPPER LEVEL LOW MOVES FROM SASKATCHEWAN INTO MANITOBA.
TO THE SOUTH...THE UPPER LEVEL RIDGE INITIALLY CENTERED OVER THE
SOUTHERN PLAINS SHOULD BECOME CENTERED OVER THE RIO GRANDE
VALLEY/NORTHERN MEXICO WHILE A FEW SHORTWAVES MOVING AROUND THIS
RIDGE TRACK FROM THE ROCKIES AND INTO THE PLAINS. THIS WILL LEAD
TO THE BEGINNING OF HEIGHT FALLS OVER THE MID MS VALLEY NORTH INTO
THE WESTERN GREAT LAKES. THIS WILL ALLOW A FRONTAL ZONE TO MOVE
DROP SOUTHEAST INTO THE ST LAWRENCE VALLEY TO CENTRAL GREAT LAKES
TO CENTRAL PLAINS.
ON TUESDAY...THE UPPER LEVEL LOW OVER CANADA SHOULD CONTINUE
TRACKING TO THE EAST NORTHEAST WITH HEIGHTS FALLING OVER THE LOWER
OH VALLEY AS SHORTWAVES MOVE FROM THE PLAINS TOWARD THE GREAT
LAKES. AT THAT POINT...THE UPPER LOW OVER THE GULF OF MEXICO AND
SOUTHEAST SHOULD BEGIN TO MERGE WITH THE TROUGH TO THE NORTH. THE
DEEPEST MOISTURE SHOULD REMAIN TO THE SOUTH OF THE AREA...WITH THE
SOUTHERN AND SOUTHEASTERN FRINGE OF THE AREA THE MOSTLY LIKELY
AREA FOR ANY CONVECTION TO FORM. GREAT CHANCES FOR CONVECTION WILL
HOLD OFF UNTIL THE LONG TERM PERIOD.
AS ALREADY NOTED...SLIGHT CHANCE POPS WERE USED ACROSS THE FAR
WEST AND SOUTH FOR TODAY. ANY CONVECTION AND CU SHOULD DISSIPATE
DURING THE EVENING...WITH DRY WEATHER ALONG WITH SOME PATCHY DENSE
RIVER VALLEY FOG AGAIN POSSIBLE TONIGHT. THIS FOG SHOULD DISSIPATE
WITHIN AN COUPLE OF HOURS AFTER SUNRISE ON TUESDAY. SLIGHT CHANCE
POPS WERE AGAIN USED ACROSS THE FAR SOUTH AND ALONG THE VA BORDER
ON TUESDAY AS DAYTIME HEATING COULD LEAD TO CONVECTION DEVELOPING
ACROSS THAT AREA. IN SUMMARY...BOTH DAYS ARE EXPECTED TO REMAIN
DRY FOR THE VAST MAJORITY OF THE REGION.
ABOVE NORMAL TEMPERATURES SHOULD PERSIST THOUGH THE PERIOD WITH A
MINOR RIDGE/VALLEY SPLIT FOR TONIGHT.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 407 AM EDT MON SEP 7 2015
THE GENERALLY DRY PATTERN AND WARM TEMPERATURES WILL FINALLY COME
TO A END.
THE PERIOD WILL BE MET WITH RIDGING FINALLY BREAKING DOWN ACROSS
THE EAST...AS A TROUGH BEGINS TO APPROACH FROM THE MIDWEST. THAT
SAID MODELS OVERALL IN GOOD AGREEMENT THROUGH MUCH OF THE FIRST
HALF OF THE PERIOD IN TERMS OF UPPER LEVELS. HOWEVER TOWARD THE
END THE AMPLITUDE/STRENGTH OF THE TROUGH COMES INTO
QUESTION...WITH THE 07/00Z ECMWF SHOWING A CUT OFF CENTERED ACROSS
THE GREAT LAKES BY SATURDAY. RIGHT NOW CONFIDENCE REMAINS LOWER
OVERALL ON THIS GIVEN THIS IS THE FIRST RUN TO BE STRENGTHENING
THE 500MB LOW TO THAT EXTENT...AND NONE OF THE OTHER LONG RANGE
MODEL OPERATIONAL RUNS ARE IN LINE WITH THIS THOUGHT. THOUGH MIGHT
BE WORTH NOTING A FEW OF THE ENSEMBLE PERTURBATIONS SEEM TO BE
PAINTING SOMETHING SIMILAR.
AT THE SURFACE THIS PERIOD WILL BE MET WITH BETTER CHANCES OF
WIDESPREAD PRECIP AS COLD FRONT APPROACHES AND MOVES THROUGH THE
REGION. BEST CHANCES RIGHT NOW LOOK TO BE WED AND THU...WITH BEST
UPPER LEVEL SUPPORT BOTH DAYS. MORE UNCERTAINTY EXISTS WITH
SECONDARY COLD FRONT TOWARD THE END OF THE OF THE PERIOD. OVERALL
LOOKS LIKE THIS WILL BE A DRIER FRONT...BUT AFOREMENTIONED CLOSED
LOW ADVERTISED BY THE ECMWF WOULD BRING BETTER CHANCES OF PRECIP
SATURDAY. RIGHT NOW STUCK CLOSER TO THE BLEND GIVEN THE MORE
UNCERTAIN PATTERN.
THE TEMPERATURES WILL CERTAINLY BE WELCOMED WITH HIGHS NEAR TO
BELOW NORMAL. WE WILL ALSO SEE A SOME 50S FOR LOWS BY THE UPCOMING
WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 735 AM EDT MON SEP 7 2015
A RIDGE OF HIGH PRESSURE HAS BROUGHT LIGHT WINDS AND MOSTLY CLEAR
TO CLEAR SKIES OVERNIGHT...WHICH HAS SET THE STAGE FOR VALLEY
FOG. THIS FOG HAS BEEN MOST PREVALENT NEAR THE RIVERS AND LAKES.
MVFR FOG GRADUALLY LIFT OUT OF LOZ THROUGH ABOUT 13Z. AT SME...
IFR IF NOT AN INDEFINITE CEILING BELOW THE AIRPORT MIN HAS BEEN
REPORTED. OTHERWISE...SJS AND JKL HAVE BEEN FREE OF FOG WITH SYM
HAVING VIS DOWN TO 7 SM. OTHER NON TAF SITE LOCATIONS SUCH AS
EKQ...W38...1A6...AND I35 WILL INITIALLY BE DOWN TO NEAR OR BELOW
AIRPORT MINS. ALL THE FOG SHOULD LIFT AND DISSIPATE BY 13Z TO 14Z.
A DIURNALLY DRIVEN CU FIELD SHOULD DEVELOP BY AROUND 16Z. AN
ISOLATED SHRA OR TSRA WILL BE POSSIBLE NEAR LOZ AND SME...AS WELL
AS NEARER TO THE VA AND TN BORDERS. CONFIDENCE IN THIS IS TOO LOW
TO INCLUDE IN THE TAF ATTM. OUTSIDE OF ANY CONVECTION VFR SHOULD
DOMINATE FROM 13Z TO 14Z THROUGH AROUND 6Z...WHEN VALLEY FOG WILL
AGAIN FORM. LOZ AND SME MAY EXPERIENCE MVFR OR LOWER FOG AGAIN
NEAR THE END OF THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR
SHORT TERM...JP
LONG TERM...DJ
AVIATION...JP
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1133 AM EDT MON SEP 7 2015
...FORECAST UPDATE...
ISSUED AT 1130 AM EDT MON SEP 7 2015
THE FORECAST IS ON TRACK FOR THIS AFTERNOON...WITH MAX TEMPS
EXPECTED TO HIT THE LOW TO MID 90S. COMPARED TO 24 HOURS
AGO...READINGS ARE ABOUT 1 TO 2 DEGREES WARMER SO FEEL CONFIDENT
WE`LL HIT THE FORECAST HIGHS.
WITH WEAK SHEAR AXIS OVERHEAD...AND WEAK SHORTWAVE RETROGRADING BACK
INTO SOUTHEAST KENTUCKY...THE SLIGHT CHANCES OF SHOWERS/STORMS LOOK
GOOD. RAP SOUNDINGS ARE SHOWING WARMER MID LEVEL TEMPERATURES
COMPARED TO THE PAST FEW DAYS...WHICH SHOULD KEEP COVERAGE/INTENSITY
TO A MINIMUM.
.SHORT TERM (NOW THROUGH TUESDAY)...
ISSUED AT 235 AM EDT MON SEP 7 2015
THE SYNOPTIC PATTERN EARLY THIS MORNING FEATURES A BROAD RIDGE
ACROSS MUCH OF THE EASTERN CONUS...WITH A VERY BROAD/WEAK LOW
CONTINUING TO SPIN BENEATH THE RIDGE OVER NORTHERN GEORGIA. A SHEAR
AXIS NOTED ON THE NORTHWEST SIDE OF THIS LOW WILL BE THE MAIN FOCUS
TODAY.
LOOKING BACK TO THE CONVECTION YESTERDAY...IT WAS ALL SPARKED WITHIN
THE SHEAR AXIS BETWEEN THE UPPER LOW TO THE SOUTHEAST AND THE
AMPLIFIED RIDGE ACROSS THE GREAT LAKES/MIDWEST REGION. AREAS MAINLY
EAST OF I-65 WILL ONCE AGAIN BE WITHIN THIS SHEAR AXIS TODAY THROUGH
WHICH VERY SUBTLE UPPER-LEVEL WAVES WILL TRAVERSE AS THEY ROTATE
AROUND THE UPPER LOW. FORECAST SOUNDINGS DO SHOW WARM AIR ALOFT
MAINLY AROUND 650-700MB...BUT IT IS NOT ALL THAT MUCH STRONGER THAN
YESTERDAY WHERE WE HAD SOME ISOLATED/WIDELY SCATTERED CONVECTION.
MANY OF THE CAMS ARE ON BOARD WITH THE IDEA OF SOME VERY ISOLATED
ACTIVITY TODAY AND THESE HAVE BEEN LEADING THE CHARGE WITH
CONVECTIVE COVERAGE THE PAST FEW DAYS. THEREFORE...WILL GO WITH 15-
20% COVERAGE WITH THE BEST CHANCES EAST OF I-65 AND SOUTH OF I-64.
LOW-LEVEL THICKNESSES REMAIN VERY SIMILIAR TO WHAT THEY`VE BEEN THE
PAST FEW DAYS...SO BARRING ANY ENHANCED CLOUD COVER FROM
CONVECTION...HIGHS FIRMLY INTO THE 90S LOOK LIKELY AGAIN TODAY.
TONIGHT WILL BE MAINLY CLEAR AND MILD...WITH LOWS IN THE MID 60S TO
LOWER 70S ONCE AGAIN. ON TUESDAY...THE UPPER LOW WILL BECOME LESS
OF A PLAYER AS IT MOVES OFF TO THE SOUTHWEST. ADDITIONALLY...THE
CAPPING TOMORROW LOOKS SUBSTANTIALLY STRONGER THAN IT DOES TODAY.
THEREFORE...WILL GO WITH A DRY FORECAST AND A PERSISTENCE FORECAST
FOR HIGH TEMPERATURES.
.LONG TERM (TUESDAY NIGHT THROUGH SUNDAY)...
ISSUED AT 305 AM EDT MON SEP 7 2015
STILL LOOKING AT A TROUGH MOVING ACROSS THE REGION
WEDNESDAY/WEDNESDAY NIGHT. THE QUESTION IS HOW MUCH PRECIPITATION
WILL MOVE INTO THE REGION WEDNESDAY MORNING AHEAD OF IT. LOOKS LIKE
SOME STORMS WILL FORM OVER MO/IL EARLY WEDNESDAY AND THESE MAY PUSH
INTO OUR NORTHWEST COUNTIES AROUND DAYBREAK. THEY COULD BRING
CLOUDINESS THROUGH THE DAY...DELAYING THE ONSET OF NEW AFTERNOON
STORMS UNTIL LATER IN THE DAY AND BRINGING TEMPERATURES DOWN. SHOULD
THESE STORMS DIE OFF QUICKER THAN IN THIS FORECAST...THEN WE WOULD
SEE A LITTLE WARMER AFTERNOON HIGHS AND AN EARLIER ONSET OF STORM
DEVELOPMENT. FOR NOW WILL CALL FOR AFTERNOON HIGHS IN THE
80S...BREAKING OUR 90+ DEGREE STRING TO START SEPTEMBER. AS FOR
SEVERITY OF THESE STORMS...MODEL WIND FIELDS ARE NOT OVERLY
IMPRESSIVE. THINK THE STRONGER GUSTS WOULD COME WITH THE LATTER
SCENARIO GIVEN ABOVE. WILL CONTINUE TO MENTION BRIEF GUSTY WINDS IN
THE HWO.
ANOTHER WEAKER SHORTWAVE LOOKS TO MOVE THROUGH THE REGION
THURSDAY...CONTINUING THE CHANCE FOR RAIN...WITH THE BEST CHANCE IN
OUR SOUTHEAST. FRIDAY CONTINUES TO TREND DRIER...BUT WITH ANOTHER
WAVE CROSS ING THE REGION CANNOT RULE OUT SOME DEVELOPMENT AT LEAST
EAST OF I-65. AFTER THAT WE SHOULD BE TOO DRY FOR FURTHER
DEVELOPMENT THIS WEEKEND...AND TEMPERATURES WILL BE QUITE
PLEASANT...WITH HIGHS IN THE 70S SATURDAY AND AROUND 80 SUNDAY.
&&
.AVIATION (12Z TAF UPDATE)...
ISSUED AT 640 AM EDT MON SEP 7 2015
AFTER SOME MORNING FOG AT KBWG AND PERHAPS SOME LIGHT FOG AT
KLEX...CONDITIONS WILL RETURN TO VFR THROUGH TODAY AND INTO TONIGHT.
CAN`T RULE OUT A STRAY STORM THIS AFTERNOON MAINLY AT KLEX OR
KBWG...BUT COVERAGE WILL BE RATHER SPARSE SO WILL NOT INCLUDE ANY
MENTION IN THE FORECAST. OTHERWISE...EXPECT JUST SOME AFTERNOON CU
WITH GENERALLY LIGHT WINDS.
FOG WILL ONCE AGAIN BE POSSIBLE TONIGHT AS WE REMAIN IN A SIMILAR
PATTERN. THUS WILL INTRODUCE MVFR VSBYS ONCE AGAIN TO KBWG AND KLEX
FOR FOG NEAR SUNRISE TUESDAY.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
UPDATE.........ZBT
SHORT TERM.....KJD
LONG TERM......RJS
AVIATION.......KJD
AREA FORECAST DISCUSSION
NWS JACKSON KY
1016 AM EDT MON SEP 7 2015
.UPDATE...
ISSUED AT 1015 AM EDT MON SEP 7 2015
UPDATED THE FORECAST TO REMOVE MENTION OF FOG FROM THE TODAY
PERIOD. ALSO UPDATED THE HOURLY GRIDS WITH THE LATEST OBS DATA TO
ESTABLISH NEW TRENDS. WILL NEED TO ISSUE ANOTHER UPDATE IN A
COUPLE OF HOURS TO REMOVE WHAT WILL THEN BE OUTDATED AFTERNOON
WORDING AND ANY OTHER NECESSARY CHANGES.
UPDATE ISSUED AT 730 AM EDT MON SEP 7 2015
HOURLY GRIDS HAVE BEEN UPDATED BASED ON RECENT
OBSERVATIONS...TRENDING DOWN A DEGREE OR TWO IN A FEW VALLEY
LOCATIONS. SFC HIGH PRESSURE WILL BRING MOSTLY DRY WEATHER TO
MUCH OF THE REGION TODAY. VALLEY FOG...DENSE IN SOME
LOCATIONS...WILL DISSIPATE BY AROUND 930 AM. CUMULUS SHOULD BEGIN
TO FORM AROUND NOON AND ISOLATED CONVECTION CANNOT BE RULED OUT.
NEAR TERM MODELS SUCH AS SEVERAL RECENT HRRR RUNS DEVELOP SOME
ISOLATED CONVECTION AROUND 1 PM...MAINLY NEAR THE TN AND VA BORDER
AND ACROSS THE WESTERN PART OF THE CWA. THIS IS IN LINE WITH THE
PREVIOUS FORECAST...SO NO CHANGES WERE MADE WITH THESE.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 350 AM EDT MON SEP 7 2015
THE REGION REMAINS DOMINATED A RIDGE HIGH PRESSURE IN THE LOWER
LEVELS THAT EXTENDS FROM THE OH VALLEY INTO THE ATLANTIC...ALTHOUGH
AT MID LEVELS THE AREA CONTINUES TO RESIDE IN A WEAKNESS BETWEEN
TWO RIDGE CENTERS ONE OVER THE ATLANTIC AND ANOTHER CENTERED OVER
THE SOUTHERN PLAINS. TO THE SOUTH OF THE AREA...A WEAK UPPER LEVEL
RIDGE REMAINS. SKIES HAVE REMAINED CLEAR TO MOSTLY CLEAR OVERNIGHT
AND VALLEY FOG HAS AGAIN FORMED. IT IS LIKELY DENSE NEAR SOME OF
THE AREA RIVERS...OF SHOULD BECOME DENSE PRIOR TO DAWN.
VERY LITTLE CHANCE IS EXPECTED IN THE UPPER PATTERN IS EXPECTED
TODAY ALTHOUGH THE WEAK UPPER LEVEL LOW OVER THE SOUTHEAST SHOULD
DRIFT SOUTHWEST. SOME OF THE MODELS HAVE HEIGHTS RISING A BIT
NORTH OF THE REGION. THE SHORT TERM MODELS GENERATE SOME CONVECTION
ACROSS THE CENTRAL TO WESTERN PARTS OF THE CWA AND NEAR THE VA AND
TN BORDERS IN SOME CASES FROM AROUND MIDDAY INTO THE AFTERNOON.
SSEO CONVECTIVE PROBABILITIES REACH THE 40 TO 60 PERCENT RANGE
ACROSS THE SOUTH AND SOUTHWESTERN PARTS OF THE CWA WITH THIS AREA
EXTENDING NORTH INTO CENTRAL KY FOR THIS AFTERNOON. GIVEN THAT
THIS HAS BEEN A GOOD PREDICTOR OF AREAS OF CONVECTION THE PAST
COUPLE OF DAYS...HAVE OPTED TO GO WITH A SLIGHT CHANCE POP IN THE
AREAS THAT IT HIGHLIGHTS WITH THESE HIGHER PROBABILITIES. WARM MID
LEVEL TEMPS SHOULD LARGELY CAP CONVECTION OVER MOST OF THE
AREA...AND THE VAST MAJORITY OF THE REGION SHOULD REMAIN DRY.
TEMPERATURES SHOULD AGAIN BE ABOVE NORMAL...IN THE UPPER 80S TO
AROUND 90 RANGE OUTSIDE OF THE HIGHEST TERRAIN.
THIS EVENING THROUGH TUESDAY...SFC HIGH PRESSURE SHOULD DOMINATE
AND BE CENTERED TO THE EAST OF THE AREA. HOWEVER...THE MID AND AND
UPPER LEVEL PATTERN SHOULD BEGIN TO CHANGE. THE WEAK UPPER LOW
OVER THE SOUTHEAST SHOULD CONTINUE MEANDERING TO THE SOUTHWEST
WHILE AN UPPER LEVEL LOW MOVES FROM SASKATCHEWAN INTO MANITOBA.
TO THE SOUTH...THE UPPER LEVEL RIDGE INITIALLY CENTERED OVER THE
SOUTHERN PLAINS SHOULD BECOME CENTERED OVER THE RIO GRANDE
VALLEY/NORTHERN MEXICO WHILE A FEW SHORTWAVES MOVING AROUND THIS
RIDGE TRACK FROM THE ROCKIES AND INTO THE PLAINS. THIS WILL LEAD
TO THE BEGINNING OF HEIGHT FALLS OVER THE MID MS VALLEY NORTH INTO
THE WESTERN GREAT LAKES. THIS WILL ALLOW A FRONTAL ZONE TO MOVE
DROP SOUTHEAST INTO THE ST LAWRENCE VALLEY TO CENTRAL GREAT LAKES
TO CENTRAL PLAINS.
ON TUESDAY...THE UPPER LEVEL LOW OVER CANADA SHOULD CONTINUE
TRACKING TO THE EAST NORTHEAST WITH HEIGHTS FALLING OVER THE LOWER
OH VALLEY AS SHORTWAVES MOVE FROM THE PLAINS TOWARD THE GREAT
LAKES. AT THAT POINT...THE UPPER LOW OVER THE GULF OF MEXICO AND
SOUTHEAST SHOULD BEGIN TO MERGE WITH THE TROUGH TO THE NORTH. THE
DEEPEST MOISTURE SHOULD REMAIN TO THE SOUTH OF THE AREA...WITH THE
SOUTHERN AND SOUTHEASTERN FRINGE OF THE AREA THE MOSTLY LIKELY
AREA FOR ANY CONVECTION TO FORM. GREAT CHANCES FOR CONVECTION WILL
HOLD OFF UNTIL THE LONG TERM PERIOD.
AS ALREADY NOTED...SLIGHT CHANCE POPS WERE USED ACROSS THE FAR
WEST AND SOUTH FOR TODAY. ANY CONVECTION AND CU SHOULD DISSIPATE
DURING THE EVENING...WITH DRY WEATHER ALONG WITH SOME PATCHY DENSE
RIVER VALLEY FOG AGAIN POSSIBLE TONIGHT. THIS FOG SHOULD DISSIPATE
WITHIN AN COUPLE OF HOURS AFTER SUNRISE ON TUESDAY. SLIGHT CHANCE
POPS WERE AGAIN USED ACROSS THE FAR SOUTH AND ALONG THE VA BORDER
ON TUESDAY AS DAYTIME HEATING COULD LEAD TO CONVECTION DEVELOPING
ACROSS THAT AREA. IN SUMMARY...BOTH DAYS ARE EXPECTED TO REMAIN
DRY FOR THE VAST MAJORITY OF THE REGION.
ABOVE NORMAL TEMPERATURES SHOULD PERSIST THOUGH THE PERIOD WITH A
MINOR RIDGE/VALLEY SPLIT FOR TONIGHT.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 407 AM EDT MON SEP 7 2015
THE GENERALLY DRY PATTERN AND WARM TEMPERATURES WILL FINALLY COME
TO A END.
THE PERIOD WILL BE MET WITH RIDGING FINALLY BREAKING DOWN ACROSS
THE EAST...AS A TROUGH BEGINS TO APPROACH FROM THE MIDWEST. THAT
SAID MODELS OVERALL IN GOOD AGREEMENT THROUGH MUCH OF THE FIRST
HALF OF THE PERIOD IN TERMS OF UPPER LEVELS. HOWEVER TOWARD THE
END THE AMPLITUDE/STRENGTH OF THE TROUGH COMES INTO
QUESTION...WITH THE 07/00Z ECMWF SHOWING A CUT OFF CENTERED ACROSS
THE GREAT LAKES BY SATURDAY. RIGHT NOW CONFIDENCE REMAINS LOWER
OVERALL ON THIS GIVEN THIS IS THE FIRST RUN TO BE STRENGTHENING
THE 500MB LOW TO THAT EXTENT...AND NONE OF THE OTHER LONG RANGE
MODEL OPERATIONAL RUNS ARE IN LINE WITH THIS THOUGHT. THOUGH MIGHT
BE WORTH NOTING A FEW OF THE ENSEMBLE PERTURBATIONS SEEM TO BE
PAINTING SOMETHING SIMILAR.
AT THE SURFACE THIS PERIOD WILL BE MET WITH BETTER CHANCES OF
WIDESPREAD PRECIP AS COLD FRONT APPROACHES AND MOVES THROUGH THE
REGION. BEST CHANCES RIGHT NOW LOOK TO BE WED AND THU...WITH BEST
UPPER LEVEL SUPPORT BOTH DAYS. MORE UNCERTAINTY EXISTS WITH
SECONDARY COLD FRONT TOWARD THE END OF THE OF THE PERIOD. OVERALL
LOOKS LIKE THIS WILL BE A DRIER FRONT...BUT AFOREMENTIONED CLOSED
LOW ADVERTISED BY THE ECMWF WOULD BRING BETTER CHANCES OF PRECIP
SATURDAY. RIGHT NOW STUCK CLOSER TO THE BLEND GIVEN THE MORE
UNCERTAIN PATTERN.
THE TEMPERATURES WILL CERTAINLY BE WELCOMED WITH HIGHS NEAR TO
BELOW NORMAL. WE WILL ALSO SEE A SOME 50S FOR LOWS BY THE UPCOMING
WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 735 AM EDT MON SEP 7 2015
A RIDGE OF HIGH PRESSURE HAS BROUGHT LIGHT WINDS AND MOSTLY CLEAR
TO CLEAR SKIES OVERNIGHT...WHICH HAS SET THE STAGE FOR VALLEY
FOG. THIS FOG HAS BEEN MOST PREVALENT NEAR THE RIVERS AND LAKES.
MVFR FOG GRADUALLY LIFT OUT OF LOZ THROUGH ABOUT 13Z. AT SME...
IFR IF NOT AN INDEFINITE CEILING BELOW THE AIRPORT MIN HAS BEEN
REPORTED. OTHERWISE...SJS AND JKL HAVE BEEN FREE OF FOG WITH SYM
HAVING VIS DOWN TO 7 SM. OTHER NON TAF SITE LOCATIONS SUCH AS
EKQ...W38...1A6...AND I35 WILL INITIALLY BE DOWN TO NEAR OR BELOW
AIRPORT MINS. ALL THE FOG SHOULD LIFT AND DISSIPATE BY 13Z TO 14Z.
A DIURNALLY DRIVEN CU FIELD SHOULD DEVELOP BY AROUND 16Z. AN
ISOLATED SHRA OR TSRA WILL BE POSSIBLE NEAR LOZ AND SME...AS WELL
AS NEARER TO THE VA AND TN BORDERS. CONFIDENCE IN THIS IS TOO LOW
TO INCLUDE IN THE TAF ATTM. OUTSIDE OF ANY CONVECTION VFR SHOULD
DOMINATE FROM 13Z TO 14Z THROUGH AROUND 6Z...WHEN VALLEY FOG WILL
AGAIN FORM. LOZ AND SME MAY EXPERIENCE MVFR OR LOWER FOG AGAIN
NEAR THE END OF THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR
SHORT TERM...JP
LONG TERM...DJ
AVIATION...JP
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
737 AM EDT MON SEP 7 2015
.UPDATE...
ISSUED AT 730 AM EDT MON SEP 7 2015
HOURLY GRIDS HAVE BEEN UPDATED BASED ON RECENT
OBSERVATIONS...TRENDING DOWN A DEGREE OR TWO IN A FEW VALLEY
LOCATIONS. SFC HIGH PRESSURE WILL BRING MOSTLY DRY WEATHER TO
MUCH OF THE REGION TODAY. VALLEY FOG...DENSE IN SOME
LOCATIONS...WILL DISSIPATE BY AROUND 930 AM. CUMULUS SHOULD BEGIN
TO FORM AROUND NOON AND ISOLATED CONVECTION CANNOT BE RULED OUT.
NEAR TERM MODELS SUCH AS SEVERAL RECENT HRRR RUNS DEVELOP SOME
ISOLATED CONVECTION AROUND 1 PM...MAINLY NEAR THE TN AND VA BORDER
AND ACROSS THE WESTERN PART OF THE CWA. THIS IS IN LINE WITH THE
PREVIOUS FORECAST...SO NO CHANGES WERE MADE WITH THESE.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 350 AM EDT MON SEP 7 2015
THE REGION REMAINS DOMINATED A RIDGE HIGH PRESSURE IN THE LOWER
LEVELS THAT EXTENDS FROM THE OH VALLEY INTO THE ATLANTIC...ALTHOUGH
AT MID LEVELS THE AREA CONTINUES TO RESIDE IN A WEAKNESS BETWEEN
TWO RIDGE CENTERS ONE OVER THE ATLANTIC AND ANOTHER CENTERED OVER
THE SOUTHERN PLAINS. TO THE SOUTH OF THE AREA...A WEAK UPPER LEVEL
RIDGE REMAINS. SKIES HAVE REMAINED CLEAR TO MOSTLY CLEAR OVERNIGHT
AND VALLEY FOG HAS AGAIN FORMED. IT IS LIKELY DENSE NEAR SOME OF
THE AREA RIVERS...OF SHOULD BECOME DENSE PRIOR TO DAWN.
VERY LITTLE CHANCE IS EXPECTED IN THE UPPER PATTERN IS EXPECTED
TODAY ALTHOUGH THE WEAK UPPER LEVEL LOW OVER THE SOUTHEAST SHOULD
DRIFT SOUTHWEST. SOME OF THE MODELS HAVE HEIGHTS RISING A BIT
NORTH OF THE REGION. THE SHORT TERM MODELS GENERATE SOME CONVECTION
ACROSS THE CENTRAL TO WESTERN PARTS OF THE CWA AND NEAR THE VA AND
TN BORDERS IN SOME CASES FROM AROUND MIDDAY INTO THE AFTERNOON.
SSEO CONVECTIVE PROBABILITIES REACH THE 40 TO 60 PERCENT RANGE
ACROSS THE SOUTH AND SOUTHWESTERN PARTS OF THE CWA WITH THIS AREA
EXTENDING NORTH INTO CENTRAL KY FOR THIS AFTERNOON. GIVEN THAT
THIS HAS BEEN A GOOD PREDICTOR OF AREAS OF CONVECTION THE PAST
COUPLE OF DAYS...HAVE OPTED TO GO WITH A SLIGHT CHANCE POP IN THE
AREAS THAT IT HIGHLIGHTS WITH THESE HIGHER PROBABILITIES. WARM MID
LEVEL TEMPS SHOULD LARGELY CAP CONVECTION OVER MOST OF THE
AREA...AND THE VAST MAJORITY OF THE REGION SHOULD REMAIN DRY.
TEMPERATURES SHOULD AGAIN BE ABOVE NORMAL...IN THE UPPER 80S TO
AROUND 90 RANGE OUTSIDE OF THE HIGHEST TERRAIN.
THIS EVENING THROUGH TUESDAY...SFC HIGH PRESSURE SHOULD DOMINATE
AND BE CENTERED TO THE EAST OF THE AREA. HOWEVER...THE MID AND AND
UPPER LEVEL PATTERN SHOULD BEGIN TO CHANGE. THE WEAK UPPER LOW
OVER THE SOUTHEAST SHOULD CONTINUE MEANDERING TO THE SOUTHWEST
WHILE AN UPPER LEVEL LOW MOVES FROM SASKATCHEWAN INTO MANITOBA.
TO THE SOUTH...THE UPPER LEVEL RIDGE INITIALLY CENTERED OVER THE
SOUTHERN PLAINS SHOULD BECOME CENTERED OVER THE RIO GRANDE
VALLEY/NORTHERN MEXICO WHILE A FEW SHORTWAVES MOVING AROUND THIS
RIDGE TRACK FROM THE ROCKIES AND INTO THE PLAINS. THIS WILL LEAD
TO THE BEGINNING OF HEIGHT FALLS OVER THE MID MS VALLEY NORTH INTO
THE WESTERN GREAT LAKES. THIS WILL ALLOW A FRONTAL ZONE TO MOVE
DROP SOUTHEAST INTO THE ST LAWRENCE VALLEY TO CENTRAL GREAT LAKES
TO CENTRAL PLAINS.
ON TUESDAY...THE UPPER LEVEL LOW OVER CANADA SHOULD CONTINUE
TRACKING TO THE EAST NORTHEAST WITH HEIGHTS FALLING OVER THE LOWER
OH VALLEY AS SHORTWAVES MOVE FROM THE PLAINS TOWARD THE GREAT
LAKES. AT THAT POINT...THE UPPER LOW OVER THE GULF OF MEXICO AND
SOUTHEAST SHOULD BEGIN TO MERGE WITH THE TROUGH TO THE NORTH. THE
DEEPEST MOISTURE SHOULD REMAIN TO THE SOUTH OF THE AREA...WITH THE
SOUTHERN AND SOUTHEASTERN FRINGE OF THE AREA THE MOSTLY LIKELY
AREA FOR ANY CONVECTION TO FORM. GREAT CHANCES FOR CONVECTION WILL
HOLD OFF UNTIL THE LONG TERM PERIOD.
AS ALREADY NOTED...SLIGHT CHANCE POPS WERE USED ACROSS THE FAR
WEST AND SOUTH FOR TODAY. ANY CONVECTION AND CU SHOULD DISSIPATE
DURING THE EVENING...WITH DRY WEATHER ALONG WITH SOME PATCHY DENSE
RIVER VALLEY FOG AGAIN POSSIBLE TONIGHT. THIS FOG SHOULD DISSIPATE
WITHIN AN COUPLE OF HOURS AFTER SUNRISE ON TUESDAY. SLIGHT CHANCE
POPS WERE AGAIN USED ACROSS THE FAR SOUTH AND ALONG THE VA BORDER
ON TUESDAY AS DAYTIME HEATING COULD LEAD TO CONVECTION DEVELOPING
ACROSS THAT AREA. IN SUMMARY...BOTH DAYS ARE EXPECTED TO REMAIN
DRY FOR THE VAST MAJORITY OF THE REGION.
ABOVE NORMAL TEMPERATURES SHOULD PERSIST THOUGH THE PERIOD WITH A
MINOR RIDGE/VALLEY SPLIT FOR TONIGHT.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 407 AM EDT MON SEP 7 2015
THE GENERALLY DRY PATTERN AND WARM TEMPERATURES WILL FINALLY COME
TO A END.
THE PERIOD WILL BE MET WITH RIDGING FINALLY BREAKING DOWN ACROSS
THE EAST...AS A TROUGH BEGINS TO APPROACH FROM THE MIDWEST. THAT
SAID MODELS OVERALL IN GOOD AGREEMENT THROUGH MUCH OF THE FIRST
HALF OF THE PERIOD IN TERMS OF UPPER LEVELS. HOWEVER TOWARD THE
END THE AMPLITUDE/STRENGTH OF THE TROUGH COMES INTO
QUESTION...WITH THE 07/00Z ECMWF SHOWING A CUT OFF CENTERED ACROSS
THE GREAT LAKES BY SATURDAY. RIGHT NOW CONFIDENCE REMAINS LOWER
OVERALL ON THIS GIVEN THIS IS THE FIRST RUN TO BE STRENGTHENING
THE 500MB LOW TO THAT EXTENT...AND NONE OF THE OTHER LONG RANGE
MODEL OPERATIONAL RUNS ARE IN LINE WITH THIS THOUGHT. THOUGH MIGHT
BE WORTH NOTING A FEW OF THE ENSEMBLE PERTURBATIONS SEEM TO BE
PAINTING SOMETHING SIMILAR.
AT THE SURFACE THIS PERIOD WILL BE MET WITH BETTER CHANCES OF
WIDESPREAD PRECIP AS COLD FRONT APPROACHES AND MOVES THROUGH THE
REGION. BEST CHANCES RIGHT NOW LOOK TO BE WED AND THU...WITH BEST
UPPER LEVEL SUPPORT BOTH DAYS. MORE UNCERTAINTY EXISTS WITH
SECONDARY COLD FRONT TOWARD THE END OF THE OF THE PERIOD. OVERALL
LOOKS LIKE THIS WILL BE A DRIER FRONT...BUT AFOREMENTIONED CLOSED
LOW ADVERTISED BY THE ECMWF WOULD BRING BETTER CHANCES OF PRECIP
SATURDAY. RIGHT NOW STUCK CLOSER TO THE BLEND GIVEN THE MORE
UNCERTAIN PATTERN.
THE TEMPERATURES WILL CERTAINLY BE WELCOMED WITH HIGHS NEAR TO
BELOW NORMAL. WE WILL ALSO SEE A SOME 50S FOR LOWS BY THE UPCOMING
WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 735 AM EDT MON SEP 7 2015
A RIDGE OF HIGH PRESSURE HAS BROUGHT LIGHT WINDS AND MOSTLY CLEAR
TO CLEAR SKIES OVERNIGHT...WHICH HAS SET THE STAGE FOR VALLEY
FOG. THIS FOG HAS BEEN MOST PREVALENT NEAR THE RIVERS AND LAKES.
MVFR FOG GRADUALLY LIFT OUT OF LOZ THROUGH ABOUT 13Z. AT SME...
IFR IF NOT AN INDEFINITE CEILING BELOW THE AIRPORT MIN HAS BEEN
REPORTED. OTHERWISE...SJS AND JKL HAVE BEEN FREE OF FOG WITH SYM
HAVING VIS DOWN TO 7 SM. OTHER NON TAF SITE LOCATIONS SUCH AS
EKQ...W38...1A6...AND I35 WILL INITIALLY BE DOWN TO NEAR OR BELOW
AIRPORT MINS. ALL THE FOG SHOULD LIFT AND DISSIPATE BY 13Z TO 14Z.
A DIURNALLY DRIVEN CU FIELD SHOULD DEVELOP BY AROUND 16Z. AN
ISOLATED SHRA OR TSRA WILL BE POSSIBLE NEAR LOZ AND SME...AS WELL
AS NEARER TO THE VA AND TN BORDERS. CONFIDENCE IN THIS IS TOO LOW
TO INCLUDE IN THE TAF ATTM. OUTSIDE OF ANY CONVECTION VFR SHOULD
DOMINATE FROM 13Z TO 14Z THROUGH AROUND 6Z...WHEN VALLEY FOG WILL
AGAIN FORM. LOZ AND SME MAY EXPERIENCE MVFR OR LOWER FOG AGAIN
NEAR THE END OF THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...JP
LONG TERM...DJ
AVIATION...JP
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1102 PM EDT TUE SEP 8 2015
.SYNOPSIS...
A WARM FRONT WILL PUSH THROUGH THE REGION OVERNIGHT BRINGING A
BAND OF RAIN SHOWERS. TOMORROW AFTERNOON A WEAK COLD FRONT WILL
PUSH THROUGH THE AREA...BRINGING ANOTHER ROUNDS OF SHOWERS AND
ISOLATED THUNDERSTORMS. SMALL BREAK IN THE WEATHER ON
THURSDAY...BEFORE A COASTAL LOW PRESSURE SYSTEM BRINGS WIDESPREAD
HEAVY RAIN TO THE COAST THURSDAY NIGHT INTO FRIDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
1025 PM UPDATE: ADJUSTED THE POPS TO BUT PERCENTAGE BACK INITIALLY
AS BEST ACTIVITY IS STILL WELL W OF THE CWA. DECIDED TO PUSH BACK
THE TIMING BY 3HRS USING THE LATEST HRRR 3KM MODEL FOR
INITIALIZATION. CLOUDS WILL FILL BACK IN LATER IN THE NIGHT AS
THE WARM FRONT LIFTS N. HRLY TEMPS WERE ADJUSTED AS WELL TO MATCH
UP WITH THE LATEST CONDITIONS AND THEREFORE, TWEAKED THE OVERNIGHT
MINS ESPECIALLY ACROSS THE EASTERN AREAS.
OVERNIGHT, THE WARM UNSTABLE AIRMASS TO THE SOUTH BEGINS TO PUSH
NORTH ONCE AGAIN AS A WARM FRONT ASSOCIATED WITH AN AREA OF LOW
PRESSURE PUSHING THROUGH QUEBEC PROVINCE. SHOWERS AND EVEN AN
ISOLATED THUNDERSTORM WILL DEVELOP TONIGHT AND PUSH FROM SOUTH TO
NORTH ALONG THE BOUNDARY. OVERALL QPF AMOUNTS WILL REMAIN
RELATIVELY LIGHT WITH LESS THEN .25" FOR MOST AREAS...COULD BE
LOCALLY HIGHER AMOUNTS IN THE CENTRAL HIGHLANDS.
DURING THE DAY ON WEDNESDAY IT WILL BE HUMID ONCE AGAIN WITH
DEWPOINT TEMPS WELL INTO THE 60S...WITH A FEW PLACES IN PENOBSCOT
TOUCHING 70. PARTIAL CLEARING IS LIKELY ACROSS DOWNEAST TOMORROW
MORNING...BUT WILL STAY MOSTLY CLOUDY ACROSS THE CROWN OF MAINE.
AFTER A SMALL BREAK A WEAK COLD FRONT WILL PUSH INTO THE REGION
LATE WEDNESDAY AFTERNOON/EARLY EVENING. SHOWERS AND ISOLATED
THUNDERSTORMS ARE EXPECTED ONCE AGAIN WITH THIS BOUNDARY.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
A COLD FRONT WILL BE DRAPED ACROSS OUR CWA AT THE START OF
WEDNESDAY NIGHT...THEN GRADUALLY SINK SOUTH AND BECOME STATIONARY
ALONG THE COAST BY THURSDAY. A LOW PRESSURE SYSTEM WILL THEN
DEVELOP ACROSS THE MID-ATLANTIC REGION AND THEN LIFT NEWD ACROSS
NEW ENGLAND THURSDAY NIGHT AND FRIDAY. STRONG UVV COMBINED WITH
HIGH PWAT VALUES WILL CREATE THE CHANCE FOR HEAVY RAINFALL ACROSS
OUR DOWNEAST ZONES...ESPECIALLY LATE THURSDAY AND FRIDAY MORNING.
WE HAVE GONE WITH A BLEND OF THE NAM12/GFS40/06Z ECMWF FOR OUR
PRECIP AMOUNTS...WHICH RESULTS IN STORM TOTAL VALUES OF UP TO 2
INCHES DOWNEAST. AS A RESULT...WE WILL MENTION THAT HEAVY RAINFALL
IS POSSIBLE DURING THIS TIME FRAME. TEMPERATURES WILL REMAIN
SEASONABLY WARM WITH HIGHS GENERALLY IN THE LOW TO MID 70S DURING
THE SHORT TERM.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
UNSETTLED WEATHER WILL CONTINUE THROUGH THE WEEKEND AND INTO NEXT
WEEK. WE`LL GET A BRIEF DRY SPELL SATURDAY WITH WEAK RIDGING, BUT
THEN AN UPPER LOW DIGGING INTO THE UPPER MIDWEST WILL BRING THE
CHANCES FOR MORE RAIN SUNDAY AND MONDAY. AS USUAL, THE LONG RANGE
MODELS DIFFER ON THE EXACT HANDLING OF THIS FEATURE ALONG WITH ITS
SURFACE REFLECTIONS. THIS MEANS THERE`S DISCREPANCIES ON WHERE THE
PRECIPITATION SETS UP AND HOW HEAVY IT`LL BE. HAVE GONE WITH
MAINLY SLIGHT CHANCE/LOW CHANCE POPS TO ACCOUNT FOR MODEL
DIFFERENCES. HIGH PRESSURE LOOKS TO SET BACK IN FOR TUESDAY.
TEMPERATURES WILL REMAIN A BIT ABOVE NORMAL, BUT NOT NEARLY TO THE
EXTENT WE`VE SEEN OVER THE PAST FEW DAYS.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
NEAR TERM: IFR CONDITIONS ARE EXPECTED TONIGHT AS A WARM MOIST
AIRMASS PUSHES INTO THE REGION. SOME RAIN SHOWERS AND A ISOLATED
THUNDERSTORM IS POSSIBLE AS A WARM FRONT PUSHES THROUGH THE ARE
TONIGHT. CONDITIONS WILL BEGIN TO IMPROVE TOMORROW MORNING WITH
GUSTY SOUTHERLY WINDS.
SHORT TERM: MVFR/IFR CIGS AND VSBYS ARE LIKELY ACROSS OUR CWA
DURING THE SHORT TERM FORECAST PERIOD WITH A FRONT MOVING THROUGH
EARLY AND THEN A LOW POSSIBLE BRINGING HEAVY RAIN TO THE AREA ON
THURSDAY NIGHT AND FRIDAY.
&&
.MARINE...
NEAR TERM: WINDS AND SEAS ARE EXPECTED TO STAY BELOW SCA TONIGHT
AND TOMORROW. WINDS WILL SHIFT FROM OFF SHORE TONIGHT TO ONSHORE
AND INCREASE IN SPEED THROUGH THE DAY.
SHORT TERM: WINDS AND SEAS ARE EXPECTED TO STAY BELOW SCA CRITERIA
WEDNESDAY NIGHT THROUGH FRIDAY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HEWITT
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
932 PM EDT TUE SEP 8 2015
.SYNOPSIS...
HIGH PRESSURE WILL SLIDE OFF THE MID ATLANTIC COAST TONIGHT THROUGH
WEDNESDAY. A COLD FRONT APPROACHES FROM THE NORTHWEST WEDNESDAY...AND
SETTLES INTO THE REGION THURSDAY. THE FRONT STALLS OVER NORTH
CAROLINA FRIDAY INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
UPDATE...SHOWERS ACROSS INTERIOR NE NC ARE FINALLY TAPERING OFF
LATE THIS EVENING AND A LULL IN ACTIVITY IS EXPECTED DURING THE
REST OF THE EVENING AND EARLY OVERNIGHT HOURS.
PREVIOUS DISCUSSION...PER LATEST RAP GUIDANCE...WEAK VORT MAX
LIFTS NEWD OVER ERN VA TONIGHT. HI-RES GUIDANCE INDICATES THE
WARM/MOIST AND MODESTLY UNSTABLE AIR MASS MAY PRODUCE SOME
ISOLATED SHOWERS OVERNIGHT ACROSS CENTRAL AND ERN VA AS THE VORT
LIFTS...ESPECIALLY OVER THE BAY AND ERN SHORE. HOWEVER...
CONFIDENCE IS NOT HIGH ATTM...SO WILL LEAVE SLIGHT CHANCE WORDING.
A PARTLY CLOUDY SKY AND DISPERSAL WILL LIMIT FOG DEVELOPMENT
TONIGHT...BUT WARM/SOUPY AIR MASS SHOULD BE ENOUGH FOR PATCHY FOG
IN AREAS THAT RECEIVED RAINFALL EARLIER TODAY. A MILD TONIGHT
AHEAD WITH LOWS IN THE LOW 70S.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
UPPER TROUGH DIGS OVER THE GREAT LAKES REGION WEDS AND
THU...RESULTING IN HEIGHT FALLS OVER THE MID-ATLANTIC REGION. AN
ASSOCIATED COLD FRONT IS EXPECTED TO REACH THE OHIO VALLEY BY WEDS
AFTERNOON. LEE/THERMAL TROUGH DEVELOPS OVER THE PIEDMONT IN
ADVANCE OF THE FRONT WEDS AFTERNOON. INCREASING SW FLOW WILL
ADVECT DEEP LAYERED MOISTURE INTO THE REGION...WITH PWATS PROGGED
AOA 2 INCHES (+1 TO +2 STD DEV). WHILE THE MAIN SHEARING VORT
ENERGY REMAINS OVER THE OHIO VALLEY...WEAK PERTURBATIONS IN THE SW
FLOW WILL PROVIDE SUBTLE FORCING FOR ASCENT OVER THE LOCAL AREA.
THETA-E ADVECTION AND DEWPOINTS IN THE LOW 70S WILL RESULT IN
BETTER INSTABILITY...WITH MLCAPE ~1500 J/KG. HAVE FAVORED THE
PIEDMONT INTO CENTRAL AND EAST CENTRAL VA FOR 30-40 PCT POPS.
WARMER TEMPS ALOFT ACROSS THE SE WILL LIMIT OVERALL COVERAGE...SO
HAVE CAPPED AT 30 PCT. EFFECTIVE SHEAR PROGGED AROUND 15 TO 20 KT
MAY RESULT IN SLIGHT BETTER ORGANIZATION...BUT SEVERE WEATHER IS
NOT ANTICIPATED. WARM AND HUMID CONDITIONS PERSIST...WITH HIGHS
FORECAST IN THE UPPER 80S TO AROUND 90 (MID 80S ALONG THE COAST).
SLIGHT CHANCE TO CHANCE POPS WILL BE MAINTAINED THROUGH WEDNESDAY
NIGHT. MILD AGAIN...WITH LOWS IN THE LOW/MID 70S.
THE FLOW CONTINUES TO AMPLIFY OVER THE GREAT LAKES AND ERN CONUS
THURSDAY AS SHORTWAVE ENERGY REACHES THE MID-ATLANTIC STATES. SFC
LOW DEVELOPS ALONG THE FRONT THU MORNING...LIFTING OVER NRN VA
INTO THE DELMARVA THU AFTERNOON AND EVENING. EXPECT
WIDESPREAD...BENEFICIAL RAINFALL THURSDAY AFTERNOON. A WARM/MOIST
AIR MASS REMAINS IN PLACE...BUT INSTABILITY WILL BE LIMITED DUE TO
CLOUD COVER AND PRECIP. HAVE RETAINED LIKELY POPS ACROSS ALL BUT
THE FAR SE LOCAL AREA. LACK OF ORGANIZED FORCING AND ANOMALOUS
FLOW WILL KEEP OVERALL QPF AOB ONE HALF OF AN INCH. WEAK FLOW AND
MBE/CORFIDI VECTORS FAVOR LOCALLY HIGHER AMOUNTS. CLOUDS/PRECIP
AND HEIGHT/THICKNESS FALLS YIELD TEMPS RANGING FROM THE LOW 80S NW
TO UPPER 80S SE.
THE FRONT STALLS ALONG THE COAST THU NIGHT AND FRI IN SWLY FLOW
ALOFT. BEST MOISTURE AND SHORTWAVE ENERGY LOCATES OVER THE COASTAL
PLAIN...AND WILL RETAIN CHANCE POPS ACROSS SOUTHERN VA AND SE
VA/NE NC. MORE SEASONABLE CONDITIONS EXPECTED FRI WITH HIGHS IN
THE LOW TO MID 80S AND DEWPOINTS COOLING INTO THE LOW 60S NW TO
UPPER 60S SE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
MODELS CONT TO STRUGGLE WITH A SOLN TO JUST HOW FAR EAST THE FRNTL
BNDRY GETS THIS WEEKEND AS IT APPRCHS THE OFFSHORE RIDGE. CONSENSUS
IS THAT IT STALLS RIGHT ALONG THE COAST AS SVRL WAVES OF LOW PRS
MOVE NE ALONG IT. IN ADDITION...A RTHR POTENT UPR LVL SYSTM
PROGGED TO DIVE SE FROM THE GT LAKE RGN LATER THIS WEEKEND. GFS
STILL FRTHER SOUTH...BUT IT IS STARTING TO COME IN LINE WITH THE
ECMWF SOLN OF SWING THE UPR LVL LOW NORTH OF FA WITH MOST OF THE
ENERGY FROM THE VA MTS ON NORTH. APPEARS HIGH PRS MOVG EAST FROM
NATIONS MID SECTION WILL BE STRNG ENUF TO PUSH THE ENTIRE SYSTM
OFFSHORE ERLY NEXT WK.
GIVEN THE ABOVE UNCERTAINTY...WILL KEEP A CONSISTENT FCST AND LEAN
MORE TOWARD A ECMWF SOLN. KEPT CHC POPS FRI NITE THRU SUN NITE
(HIGHEST POPS ALONG THE COAST AND MENTION THUNDER IN THE IN AFTN AND
EVE). DRY MON/TUE. A COOLING TREND THRU THE PRD. HIGHS SAT 80-
85...COOLER AT THE BEACHES. LOWS 60-65. HIGHS SUN/MON 75-80. LOWS
M50S-L60S. HIGHS TUE U70S-L80S.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
VFR CONDS ACROSS THE REGION AND TAF SITES WITH NO STORMS IN THE
CWA. SATELLITE SHOWING GENERAL CLEARING. WINDS ARE MOSTLY LIGHT
FROM THE SE LESS THAN 10 KT. SOME FOG POSSIBLE DURING THE
OVERNIGHT BUT GUIDANCE AND SNDGS NOT SHOWING ANYTHING OF
SIGNIFICANCE. THERE WILL BE A CHANCE OF SHRAS/TSTMS FM WED THRU
FRI AS A COLD FRNT APPROACHES FM THE W AND STALLS IN THE VICINITY.
&&
.MARINE...
NO HEADLINES XPCT AS HIGH PRS MOVES OFFSHORE RESULTING IN A RETURN
SLY FLOW THRU THURSDAY. ONCE AGAIN...HIGH RES DATA SUGGESTS SOME
CHANNELING UP THE BAY AT NIGHT...SO KEPT SPEEDS AOB 15 KTS FOR
NOW. COLD FRONT APPRCHS THE AREA THURSDAY AFTN THEN CROSSES THE
WTRS THURSDAY NIGHT BEFORE STALLING JUST OFF THE COAST FRIDAY.
LACK OF CAA BEHIND THE FRONT WILL KEEP SUB-SCA CNDTNS INTO FRIDAY.
LOCATION OF FRONT INTO THE WEEKEND WILL BE KEY TO THE FCST. RIGHT
NOW THE BNDRY LOOKS TO STRADDLE THE COAST KEEPING WNDS IN A GNRL
WEST DRCTN AT SPEEDS ARND 10 KTS.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...AJZ/SAM
NEAR TERM...AJZ/BMD/SAM
SHORT TERM...AJZ/SAM
LONG TERM...MPR
AVIATION...DAP/JEF
MARINE...MPR
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
922 PM EDT TUE SEP 8 2015
.SYNOPSIS...
HIGH PRESSURE WILL SLIDE OFF THE MID ATLANTIC COAST TONIGHT THROUGH
WEDNESDAY. A COLD FRONT APPROACHES FROM THE NORTHWEST WEDNESDAY...AND
SETTLES INTO THE REGION THURSDAY. THE FRONT STALLS OVER NORTH
CAROLINA FRIDAY INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
UPDATE...SHOWERS ACROSS INTERIOR NE NC ARE FINALLY TAPERING OFF
LATE THIS EVENING AND A LULL IN ACTIVITY IS EXPECTED DURING THE
REST OF THE EVENING AND EARLY OVERNIGHT HOURS.
PREVIOUS DISCUSSION...PER LATEST RAP GUIDANCE...WEAK VORT MAX
LIFTS NEWD OVER ERN VA TONIGHT. HI-RES GUIDANCE INDICATES THE
WARM/MOIST AND MODESTLY UNSTABLE AIR MASS MAY PRODUCE SOME
ISOLATED SHOWERS OVERNIGHT ACROSS CENTRAL AND ERN VA AS THE VORT
LIFTS...ESPECIALLY OVER THE BAY AND ERN SHORE. HOWEVER...
CONFIDENCE IS NOT HIGH ATTM...SO WILL LEAVE SLIGHT CHANCE WORDING.
A PARTLY CLOUDY SKY AND DISPERSAL WILL LIMIT FOG DEVELOPMENT
TONIGHT...BUT WARM/SOUPY AIR MASS SHOULD BE ENOUGH FOR PATCHY FOG
IN AREAS THAT RECEIVED RAINFALL EARLIER TODAY. A MILD TONIGHT
AHEAD WITH LOWS IN THE LOW 70S.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
UPPER TROUGH DIGS OVER THE GREAT LAKES REGION WEDS AND
THU...RESULTING IN HEIGHT FALLS OVER THE MID-ATLANTIC REGION. AN
ASSOCIATED COLD FRONT IS EXPECTED TO REACH THE OHIO VALLEY BY WEDS
AFTERNOON. LEE/THERMAL TROUGH DEVELOPS OVER THE PIEDMONT IN
ADVANCE OF THE FRONT WEDS AFTERNOON. INCREASING SW FLOW WILL
ADVECT DEEP LAYERED MOISTURE INTO THE REGION...WITH PWATS PROGGED
AOA 2 INCHES (+1 TO +2 STD DEV). WHILE THE MAIN SHEARING VORT
ENERGY REMAINS OVER THE OHIO VALLEY...WEAK PERTURBATIONS IN THE SW
FLOW WILL PROVIDE SUBTLE FORCING FOR ASCENT OVER THE LOCAL AREA.
THETA-E ADVECTION AND DEWPOINTS IN THE LOW 70S WILL RESULT IN
BETTER INSTABILITY...WITH MLCAPE ~1500 J/KG. HAVE FAVORED THE
PIEDMONT INTO CENTRAL AND EAST CENTRAL VA FOR 30-40 PCT POPS.
WARMER TEMPS ALOFT ACROSS THE SE WILL LIMIT OVERALL COVERAGE...SO
HAVE CAPPED AT 30 PCT. EFFECTIVE SHEAR PROGGED AROUND 15 TO 20 KT
MAY RESULT IN SLIGHT BETTER ORGANIZATION...BUT SEVERE WEATHER IS
NOT ANTICIPATED. WARM AND HUMID CONDITIONS PERSIST...WITH HIGHS
FORECAST IN THE UPPER 80S TO AROUND 90 (MID 80S ALONG THE COAST).
SLIGHT CHANCE TO CHANCE POPS WILL BE MAINTAINED THROUGH WEDNESDAY
NIGHT. MILD AGAIN...WITH LOWS IN THE LOW/MID 70S.
THE FLOW CONTINUES TO AMPLIFY OVER THE GREAT LAKES AND ERN CONUS
THURSDAY AS SHORTWAVE ENERGY REACHES THE MID-ATLANTIC STATES. SFC
LOW DEVELOPS ALONG THE FRONT THU MORNING...LIFTING OVER NRN VA
INTO THE DELMARVA THU AFTERNOON AND EVENING. EXPECT
WIDESPREAD...BENEFICIAL RAINFALL THURSDAY AFTERNOON. A WARM/MOIST
AIR MASS REMAINS IN PLACE...BUT INSTABILITY WILL BE LIMITED DUE TO
CLOUD COVER AND PRECIP. HAVE RETAINED LIKELY POPS ACROSS ALL BUT
THE FAR SE LOCAL AREA. LACK OF ORGANIZED FORCING AND ANOMALOUS
FLOW WILL KEEP OVERALL QPF AOB ONE HALF OF AN INCH. WEAK FLOW AND
MBE/CORFIDI VECTORS FAVOR LOCALLY HIGHER AMOUNTS. CLOUDS/PRECIP
AND HEIGHT/THICKNESS FALLS YIELD TEMPS RANGING FROM THE LOW 80S NW
TO UPPER 80S SE.
THE FRONT STALLS ALONG THE COAST THU NIGHT AND FRI IN SWLY FLOW
ALOFT. BEST MOISTURE AND SHORTWAVE ENERGY LOCATES OVER THE COASTAL
PLAIN...AND WILL RETAIN CHANCE POPS ACROSS SOUTHERN VA AND SE
VA/NE NC. MORE SEASONABLE CONDITIONS EXPECTED FRI WITH HIGHS IN
THE LOW TO MID 80S AND DEWPOINTS COOLING INTO THE LOW 60S NW TO
UPPER 60S SE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
MODELS CONT TO STRUGGLE WITH A SOLN TO JUST HOW FAR EAST THE FRNTL
BNDRY GETS THIS WEEKEND AS IT APPRCHS THE OFFSHORE RIDGE. CONSENSUS
IS THAT IT STALLS RIGHT ALONG THE COAST AS SVRL WAVES OF LOW PRS
MOVE NE ALONG IT. IN ADDITION...A RTHR POTENT UPR LVL SYSTM
PROGGED TO DIVE SE FROM THE GT LAKE RGN LATER THIS WEEKEND. GFS
STILL FRTHER SOUTH...BUT IT IS STARTING TO COME IN LINE WITH THE
ECMWF SOLN OF SWING THE UPR LVL LOW NORTH OF FA WITH MOST OF THE
ENERGY FROM THE VA MTS ON NORTH. APPEARS HIGH PRS MOVG EAST FROM
NATIONS MID SECTION WILL BE STRNG ENUF TO PUSH THE ENTIRE SYSTM
OFFSHORE ERLY NEXT WK.
GIVEN THE ABOVE UNCERTAINTY...WILL KEEP A CONSISTENT FCST AND LEAN
MORE TOWARD A ECMWF SOLN. KEPT CHC POPS FRI NITE THRU SUN NITE
(HIGHEST POPS ALONG THE COAST AND MENTION THUNDER IN THE IN AFTN AND
EVE). DRY MON/TUE. A COOLING TREND THRU THE PRD. HIGHS SAT 80-
85...COOLER AT THE BEACHES. LOWS 60-65. HIGHS SUN/MON 75-80. LOWS
M50S-L60S. HIGHS TUE U70S-L80S.
&&
.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
AMPLE DEEP LAYER MOISTURE AND INSTABILITY HAVE HELPED INITIATE
SHOWERS AND THUNDERSTORMS ALONG A WEAK AREA OF LOW PRESSURE ACROSS
NE NC/SE VA. STORMS WILL PROGRESS NW ALONG A GUST FRONT BOUNDARY.
EXPECT REDUCED VIS AND AND GUSTS TO ~20KT DURING ANY STORM. FOG
WILL BE POSSIBLE WED MORNING AS SKIES CLEAR AND WINDS BECOME
LIGHT. THERE WILL BE A CHANCE OF SHRAS/TSTMS FM WED THRU FRI AS A
COLD FRNT APPROACHES FM THE W AND STALLS IN THE VICINITY.
&&
.MARINE...
NO HEADLINES XPCT AS HIGH PRS MOVES OFFSHORE RESULTING IN A RETURN
SLY FLOW THRU THURSDAY. ONCE AGAIN...HIGH RES DATA SUGGESTS SOME
CHANNELING UP THE BAY AT NIGHT...SO KEPT SPEEDS AOB 15 KTS FOR
NOW. COLD FRONT APPRCHS THE AREA THURSDAY AFTN THEN CROSSES THE
WTRS THURSDAY NIGHT BEFORE STALLING JUST OFF THE COAST FRIDAY.
LACK OF CAA BEHIND THE FRONT WILL KEEP SUB-SCA CNDTNS INTO FRIDAY.
LOCATION OF FRONT INTO THE WEEKEND WILL BE KEY TO THE FCST. RIGHT
NOW THE BNDRY LOOKS TO STRADDLE THE COAST KEEPING WNDS IN A GNRL
WEST DRCTN AT SPEEDS ARND 10 KTS.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...AJZ/SAM
NEAR TERM...AJZ/BMD/SAM
SHORT TERM...AJZ/SAM
LONG TERM...MPR
AVIATION...MAS/DAP
MARINE...MPR
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
752 PM EDT TUE SEP 8 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 417 PM EDT TUE SEP 8 2015
WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A MID/UPPER LEVEL LOW
SPINNING OVER MANITOBA. ONE SHORTWAVE IS LIFTING NE ACROSS NRN
ONTARIO TO THE N OF LAKE OF THE WOODS. TAIL END OF THAT WAVE IS
GENERATING SHRA/TSRA N OF THE MN/ONTARIO BORDER. CLOSER TO HOME...
SHORTWAVE THAT LIFTED ACROSS WI TOWARD ERN UPPER MI BROUGHT
WIDESPREAD SHRA/ISOLD TSTMS ACROSS ALL BUT FAR WRN UPPER MI TODAY.
THAT ACTIVITY IS MOVING OUT QUICKLY NOW. TO THE W...IT APPEARS THAT
THERE ARE 2 BOUNDARIES THAT STILL NEED TO BE WATCHED FOR NEW
CONVECTIVE DEVELOPMENT. THE FIRST IS LAKE BREEZE BOUNDARY RUNNING
FROM THE E SIDE OF THE KEWEENAW TO CNTRL GOGEBIC COUNTY...AND THE
OTHER IS THE COLD FRONT MOVING ACROSS THE WRN PART OF LAKE SUPERIOR.
MOSTLY FOLLOWED RECENT RADAR TRENDS TO MOVE LINGERING WIDESPREAD
SHRA OUT OF THE ERN FCST AREA OVER THE NEXT FEW HRS. HELD LOW POPS
BACK TO THE W AHEAD OF THE TWO AFOREMENTIONED BOUNDARIES. LATEST SPC
MESOANALYSIS HAS MLCAPES UP TO AROUND 250J/KG OR SO AND SBCAPE TO
AROUND 500J/KG AHEAD OF THE BOUNDARIES. WITH CU BUILDING UP PER VIS
SATELLITE IMAGERY...CAN`T RULE OUT ISOLD/SCT SHRA DEVELOPMENT...
PERHAPS A TSTM. WHATEVER HAPPENS...PCPN RISK WILL BE DONE BY LATE
EVENING AS COLD FRONT SWEEPS ACROSS THE AREA. MUCH DRIER AIR MASS
SURGING INTO THE AREA WILL FINALLY BRING AN END TO THE UNSEASONABLY
LONG STRETCH OF HIGH DWPTS FOR THIS TIME OF YEAR. UPSTREAM IN NRN
MN...SFC DWPTS HAVE FALLEN THRU THE 40S WITH EVEN SOME 30S SHOWING
UP. EXPECT CLEARING SKIES FROM THE W TONIGHT. IF THERE IS ANY FOG ON
LAKE SUPERIOR...IT WILL AFFECT THE ERN SHORELINE AREAS BEFORE BEING
SWEPT CLEAR BY THE MUCH DRIER AIR MASS. IT WILL BE THE COOLEST NIGHT
IN WELL OVER A WEEK. MIN TEMPS SHOULD FALL INTO THE MID 40S OVER THE
INTERIOR W HALF AND MOSTLY LOW/MID 50S ELSEWHERE.
DRY AIR MASS WILL SET UP A NICE WED UNDER PLENTY OF SUNSHINE. DWPTS
WILL BE LOW...MOSTLY IN THE 40S...WITH HIGH TEMPS IN THE UPPER 60S
TO MID 70S...WARMEST IN THE AREAS THAT SEE DOWNSLOPING UNDER A
WESTERLY WIND. SPEAKING OF WHICH...WINDS SHOULD BE GUSTY INTO THE 20
TO 30 MPH RANGE...ESPECIALLY OVER THE NW FCST AREA.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 414 PM EDT TUE SEP 8 2015
THE UPPER TROUGH THAT IS CURRENTLY MOVING EAST ACROSS SOUTH CENTRAL
CANADA AND THE UPPER MISSISSIPPI VALLEY WILL MOVE INTO THE UPPER
GREAT LAKES OVER THE NEXT 12 HOURS AND THEN AMPLIFY OVER THE REGION
HEADING INTO THE END OF THE WORK WEEK AS A WAVE CURRENTLY MOVING
INTO BRITISH COLUMBIA ROTATES THROUGH. THIS SETUP WILL LEAD TO
GENERALLY BELOW NORMAL TEMPERATURES INTO THE START OF THE WEEKEND
WITH PERIODS OF SHOWERS.
AFTER A DRY START TO THE LONG TERM PERIOD ON WEDNESDAY EVENING
(DUE TO AN EXISTING HIGH PRESSURE RIDGE)...A WEAK SURFACE TROUGH
WILL MOVE EAST ACROSS THE UPPER MISSISSIPPI VALLEY AND INTO THE
GREAT LAKES REGION LATER WEDNESDAY NIGHT AND THURSDAY. THIS WILL BE
IN RESPONSE TO THE SHORTWAVE CURRENTLY MOVING INTO BRITISH COLUMBIA
THAT WILL BE ROUNDING THE BASE OF THE UPPER TROUGH. SHOWERS ARE
EXPECTED TO DEVELOP IN SOUTHERN MINNESOTA AND WESTERN WISCONSIN
ON WEDNESDAY NIGHT AND THEN SPREADING EAST-NORTHEAST INTO PORTIONS
OF UPPER MICHIGAN. MODELS ARE DIFFERING ON THE NORTHWEST EXTENT OF
THE SHOWERS...LARGELY DUE TO THE TRACK OF THE SHORTWAVE WITH HALF
TRACKING IT ACROSS NORTHERN WISCONSIN (PUSHING PRECIP FARTHER NORTH)
AND THE OTHER HALF TRACK IT MORE ACROSS SOUTHERN WISCONSIN (AND HAS
PRECIP ONLY BRUSHING THE SOUTHERN THIRD OF THE AREA) ON THURSDAY.
DID SEE A SOUTHEAST TREND WITH THE 12Z ECMWF...WHICH IS MORE IN LINE
WITH THE 12Z GFS/GEM...SO WHILE CONFIDENCE IS LOW...FELT IT WAS
REASONABLE TO TREND THE CHANCE POPS FARTHER TO THE SOUTHEAST AND
MORE OVER THE SOUTH CENTRAL AND ALONG THE LAKE MICHIGAN SHORELINE.
THOSE SHOWERS WILL DEPART ON THURSDAY NIGHT AS THE SHORTWAVE AND
SURFACE TROUGH DEPARTS. THIS WILL ALLOW MUCH COLDER AIR TO SURGE
SOUTH ACROSS THE AREA THURSDAY NIGHT INTO FRIDAY...WITH 850MB TEMPS
FALLING TO 1-2C. SINCE LAKE SUPERIOR TEMPERATURES ARE IN THE 12-18C
RANGE...EXPECT SOME POTENTIAL OF LAKE EFFECT/ENHANCED RAIN FOR
THURSDAY NIGHT INTO FRIDAY. MODELS SHOWING DECENT MOISTURE BELOW
THE INVERSION AROUND 750MB...SO HAVE CHANCE POPS FOR THE FAVORED
NORTHERLY WIND LOCATIONS NEAR LAKE SUPERIOR DURING THAT TIME.
WILL LIKELY NEED TO TREND POPS UP FURTHER IF THE LATEST MODEL
TRENDS CONTINUE. IN ADDITION...THAT COLD AIR AND DECENT CLOUD COVER
FOR MUCH OF THE DAY ON FRIDAY WILL KEEP HIGHS IN THE 50S.
A SURFACE HIGH OFF TO THE WEST IN THE DAKOTAS WILL TRY TO PUSH A
SURFACE RIDGE INTO THE AREA ON FRIDAY...BUT IT WILL LIKELY REALLY
ARRIVE ON SATURDAY AS THE UPPER TROUGH BEGINS TO SHIFT EAST. DRIER
AIR ASSOCIATED WITH THE HIGH WILL LEAD TO DECREASING CLOUDS FROM
WEST TO EAST ON FRIDAY AFTERNOON...WITH CLEAR SKIES REMAINING IN
PLACE THROUGH MUCH OF THE WEEKEND. SATURDAY WILL REMAIN BELOW
NORMAL FOR HIGHS...BUT WITH THE UPPER RIDGE AXIS SHIFTING EAST FROM
THE DAKOTAS AND INTO THE UPPER GREAT LAKES REGION FOR SUNDAY AND
MONDAY...EXPECT HIGHS TO RISE BACK UP TO NORMAL OR EVEN SLIGHTLY
ABOVE NORMAL VALUES. WILL NEED TO WATCH THE EVOLUTION OF THE UPPER
TROUGH JUST TO THE EAST-SOUTHEAST OF THE AREA FOR SUNDAY/MONDAY
TIME FRAME...AS THERE ARE SOME HINTS OF IT ROTATING BACK NORTHWEST
AS THE UPPER RIDGE REMAINS FARTHER WEST. THAT WOULD LEAD TO COOLER
AND BETTER OPPORTUNITIES FOR RAIN.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 750 PM EDT TUE SEP 8 2015
COLD FRONT HAS WORKED THROUGH KIWD AND KCMX. EXPECT VFR CONDITIONS
THROUGH WEDNESDAY. WEST WINDS WILL BECOME GUSTY FOR A TIME THIS
EVENING AT KCMX...THEN AGAIN ON WEDNESDAY AT KIWD AND KCMX. COLD
FRONT STILL WEST OF KSAW...SO THERE MAY STILL BE ISOLD SHRA THERE IN
THE NEXT COUPLE HOURS. EXPECT VFR CONDITIONS TO PREVAIL THOUGH INTO
WEDNESDAY WITH GUSTY WEST WINDS DEVELOPING AS WELL. WINDS ARE EXPECTED
TO GUST TO 18-26 KTS ON WEDNESDAY AT ALL THE TERMINALS...STRONGEST
AT THE MORE EXPOSED KCMX LOCATION.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 417 PM EDT TUE SEP 8 2015
FIRST UP...IF THERE IS ANY FOG ON LAKE SUPERIOR...IT WILL BE SWEPT
OFF THE ERN PORTION OF THE LAKE TONIGHT AS STRENGTHENING W WINDS
BEHIND A PASSING COLD FRONT USHER IN A MUCH DRIER AIR MASS TONIGHT.
INCOMING PRES RISES WILL HELP BOOST W WIND GUSTS TO 25-30KT FOR A
TIME AFTER FRONTAL PASSAGE. DURING WED...W WINDS OF 15-25KT WILL
GENERALLY BE THE RULE...BUT OVER CNTRL LAKE SUPERIOR AND IN
PARTICULAR AROUND THE TIP OF THE KEWEENAW PENINSULA...WINDS OF 20-
30KT ARE EXPECTED. LIGHTER WINDS OF 10-20KT ARE EXPECTED FOR WED
NIGHT/THU. ARRIVAL OF A COLDER AIR MASS AHEAD OF APPROACHING SFC
HIGH PRES WILL LEAD TO A PERIOD OF STRONGER WINDS OF 15-30KT AGAIN
THU NIGHT INTO AT LEAST FRI MORNING...STRONGEST OVER THE E HALF.
WINDS WILL SLOWLY DIMINISH W TO E FRI AFTN THRU SAT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...JLA
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
102 PM EDT MON SEP 7 2015
.AVIATION...
COLD FRONT SLOWLY SLIDING INTO SOUTHEAST MICHIGAN THIS AFTERNOON
EXPECTED TO TOUCH OFF SCATTERED SHOWER/THUNDERSTORM ACTIVITY...BUT
PREFERENCE IS TO INCLUDE JUST TEMPO GROUP FOR SHOWERS ACROSS
NORTHERN TAF SITES...UNTIL BETTER HANDLE ON THUNDERSTORM COVERAGE IS
REALIZED. FRONTAL BOUNDARY WILL BE STALLED/NEARLY STATIONARY OVER
THE AREA TONIGHT...AND UPTICK IN SHOWER/THUNDERSTORM ACTIVITY IS
EXPECTED AS LOW LEVEL CONVERGENCE/JET INCREASES A BIT.
HOWEVER...EXACT POSITION OF THIS EXPANDING COVERAGE OF ACTIVITY IS
UNCERTAIN...BUT EXPECTATIONS ARE FOR MIGRATORY NORTHWARD JOG THROUGH
THE NIGHT. OUTSIDE OF THIS ACTIVITY...VFR CEILINGS ARE EXPECTED WITH
LIGHT WINDS (SAVE FOR THIS AFTERNOONS SOUTHWEST WINDS ABOVE 10
KNOTS). FOG WILL LIKELY BECOME AN ISSUE TONIGHT...ESPECIALLY IF
CONVECTIVE ACTIVITY/MID CLOUDS DO NOT PAN OUT...BUT HAVE GONE
MOSTLY CONSERVATIVE (MVFR) FOR NOW.
FOR DTW...THERE REMAINS A LOW CHANCE OF SHOWERS AND THUNDERSTORMS
LATE THIS AFTERNOON INTO EARLY THIS EVENING...BUT HAVE ELECTED TO
INCLUDE THE BETTER CHANCE IN THE TAF TOWARD MIDNIGHT.
FOR DTW...
//DTW THRESHOLD PROBABILITIES...
* LOW CONFIDENCE IN THUNDERSTORMS LATE TODAY THROUGH TOMORROW.
* LOW CONFIDENCE IN CEILINGS AOB 5000 FEET.
&&
.PREV DISCUSSION...ISSUED 1051 AM EDT MON SEP 7 2015
UPDATE...
THE PROSPECTS FOR SHOWERS/THUNDERSTORMS STILL LOOKS TO BE FAIRLY
LOW/SCATTERED COVERAGE EXPECTED TODAY...AS UPPER LEVEL RIDGE (589
DAM AT 500 MB )IN PLACE IS SLOW TO FLATTEN. SURFACE COLD
FRONT/FOLDING OVER MOISTURE PLUME (PW OF 2 INCHES)/850-700 MB THETA-
E RIDGE AXIS WILL PROVIDE FOCUS FOR ACTIVITY...BUT THE FRONT IS
DISPLACED EAST OF THE UPPER LEVEL FORCING...AS 500 MB TEMPS ACTUALLY
LOOK TO RISE TOWARD -6 C TOWARD 00Z TUESDAY. MID LEVEL LAPSE RATES
(700-500 MB) WILL BE WEAK TODAY...BUT ENOUGH MLCAPE (1000-1500 J/KG)
BUILDING TO MAINTAIN THUNDERSTORM THREAT...BUT 0-6 KM BULK SHEAR
GENERALLY AROUND 20 KNOTS...DOES NOT DRAW A HUGE CONCERN FOR
SEVERE WEATHER...BUT VERY HEAVY RAINFALL IS CERTAINTY EXPECTED
WITH ANY STORM. DEEP LAYER UNIDIRECTIONAL WEST-SOUTHWEST WINDS
SHOULD KEEP CELLS MOVING JUST ENOUGH. 12Z NAM AND LATEST RUC BEING
A BIT MORE GENEROUS WITH COVERAGE OVER NORTH HALF OF THE CWA THIS
AFTERNOON...WITH LITTLE OR NO CAP IN THIS MOIST ENVIRONMENT.
HOWEVER...FORECASTED SURFACE DEW PTS LOOK TO BE A TOUCH TOO
HIGH...BUT STILL MAY DECIDE TO NUDGE POPS UP A JUST A
BIT...DEPENDING ON TREND AND FURTHER ANALYSIS.
TEMPERATURES REMAIN ON TRACK TO REACH INTO THE MID/UPPER 80S...WITH
90 DEGREES LIKELY ACROSS EASTERN AREAS...INCLUDING CITY OF DETROIT.
HIGH BASED CLOUDS SHOULD PROVIDE MODEST RELIEF...BUT CERTAINLY HOT
WITH DEW PTS IN 65 TO 70 DEGREE RANGE. INDICATIVE OF THIS HOT AND
MOIST AIRMASS...FLINT AND SAGINAW COULD SET RECORD HIGH MINIMUM
VALUES FOR TODAY (SEPTEMBER 7). SAGINAW LOW THIS MORNING WAS 73
DEGREES...WITH THE RECORD BEING 71 DEGREES SET IN 1985.
MEANWHILE...FLINT BOTTOMED OUT AT 71 DEGREES...WHICH WOULD TIE THE
RECORD HIGH MINIMUM FOR THE DATE...PREVIOUSLY SET IN 2007.
HOWEVER...STILL HAVE POTENTIAL FOR TEMPERATURES TO DROP TOWARD 70
DEGREES BY MIDNIGHT TONIGHT...ESPECIALLY WITH ANY HELP FROM RAIN
COOLED SHOWERS.
PREV DISCUSSION...ISSUED 323 AM EDT MON SEP 7 2015
SHORT TERM...TODAY AND TONIGHT
CONVECTION REMAINS FIRMLY ANCHORED TO ENHANCED SOUTHWESTERLY FLOW
ATTENDANT TO THE LEAD EDGE OF HEIGHT FALLS OVER THE WESTERN AND
NORTHERN GREAT LAKES EARLY THIS MORNING. NWP ADAMANTLY KILL THIS
ACTIVITY DURING THE EARLY MORNING, BUT THETA-E TRANSPORT HAS PROVEN
IMPRESSIVE AND CONVECTION OVER NORTHERN IL/SOUTHERN WI HAS SO FAR
BEEN RESILIENT. THE CORE OF THE LLJ AXIS WITHIN WHICH THIS ACTIVITY
IS EMBEDDED WILL GRADUALLY WEAKEN THROUGH MORNING WHICH DOES SUPPORT
EVENTUAL UPSTREAM DISSIPATION BEFORE THE LLJ FINALLY IMPINGES ON THE
FAR WESTERN CWA AFTER ABOUT 20Z. HOWEVER, DIURNAL HEATING - TEMPERED
BY CONVECTIVE DEBRIS - AND SOME DEGREE OF ONGOING MOISTURE TRANSPORT
WITHIN WEAKER SWLY FLOW OUGHT TO BE SUFFICIENT TO REGENERATE SHOWERS
ALONG THE EASTERN FRINGE OF WHAT REMAINS OF THE ENHANCED
SOUTHWESTERLIES AFTER 18Z. INDEED, PROGGED NAM12 SOUNDINGS DEPICT AN
IMPRESSIVE MOISTENING ABOVE THE LFC WHICH SHOULD HELP GET THINGS
GOING, CONDITIONAL ON SUFFICIENT BOUNDARY LAYER DEEPENING. RECENT
HRRR CYCLES SUPPORT THE IDEA OF REGENERATION AS WELL. LACK OF
INSTABILITY AND SHEAR WILL LIMIT TSTORM POTENTIAL IN GENERAL, BUT
PWATS NEAR 2 INCHES ARE A NOD TO THE PRIMARY THREAT OF HEAVY RAIN
WITH ANYTHING THAT DEVELOPS. THOUGH SENSITIVE TO CONVECTIVE
COVERAGE, HIGHS SHOULD EASILY REACH 90 ACROSS THE FAR EAST, WHILE
THICKER CLOUD COVER EARLIER IN THE DAY IS FORECAST TO LIMIT THE
SAGINAW VALLEY TO THE MID 80S.
RAPID INTENSIFYING OF THE UPPER JET OVER LAKE SUPERIOR WILL ENSUE BY
SEVERAL HOURS AFTER SUNSET MARKING THE ARRIVAL OF MORE VIGOROUS
UPPER ENERGY EMBEDDED WITHIN BROAD CYCLONIC FLOW AROUND THE MANITOBA
CYCLONE. LOWER TROPOSPHERIC FRONTAL ZONE WILL UNDERGO SUBSEQUENT
SHARPENING WHILE A SECONDARY THETA-E SURGE ORGANIZES WITHIN THE
RENEWED LLJ EMERGING OUT OF THE MIDDLE MS VALLEY. THE PRIMARY
UNCERTAINTY DURING THIS TIME IS WHETHER THIS PROCESS WILL ULTIMATELY
SUSTAIN EXISTING/LEFT OVER DIURNAL ACTIVITY OR IF DAYTIME ACTIVITY
WILL WANE COMPLETELY AND GIVE WAY TO SEVERAL HOURS OF DOWN-TIME
BEFORE ISENTROPIC ASCENT RAMPS UP AFTER MIDNIGHT. THIS WILL LIKELY
MAKE ALL THE DIFFERENCE FOR THE DETROIT METRO AREA, AS DISSIPATION
OF DIURNAL ACTIVITY WOULD LIKELY SPELL THE END OF RAIN POTENTIAL FOR
THE EVENING AS FORCING ULTIMATELY REORGANIZES ORGANIZES FURTHER
NORTH ALONG THE M59/I-69 CORRIDOR. CONFIDENCE BY EARLY TUESDAY
MORNING IS HIGHEST IN THE SAGINAW VALLEY WITHIN THE CORRIDOR OF
STRONGEST ASCENT AND DECREASES TOWARD THE THUMB. POPS ARE THEREFORE
TAPERED FROM CATEGORICAL FOR THE FORMER TO ENTRY LEVEL LIKELY FOR
THE LATTER. SKINNY CAPE PROFILE, 2+" PWATS, AND DEVELOPING 12KFT
WARM CLOUD LAYER WILL CERTAINLY SUPPORT AN ENVIRONMENT CAPABLE OF
PROLIFIC HYDROMETEOR PRODUCTION AND RESULTANT HEAVY DOWNPOURS.
ACCORDINGLY, QPF HAS BEEN RAMPED UP TO BASIN AVERAGES OF ABOUT A
HALF INCH AFTER MIDNIGHT. DEPENDING ON COVERAGE, THE POTENTIAL FOR
FURTHER UPWARD ADJUSTMENT WILL EXIST.
LOWS WILL HOVER NEAR 70 FOR YET ANOTHER NIGHT AS HIGH DEWPOINTS PUT
AN A FLOOR ON LOW TEMP POTENTIAL. SOME RELIEF ACROSS THE NORTH WILL
COME IN THE FORM OF RAINFALL, BUT SOUTHERN AREAS WILL REMAIN LARGELY
PRECIP FREE AFTER SUNSET AND WILL BE WARM AND MUGGY ONCE AGAIN.
LONG TERM...
THE LONG TERM WILL FIRST DEAL WITH A LONG DURATION RAINFALL ALONG A
STALLED FRONT...FOLLOWED BY THE INFILTRATION OF A MUCH COOLER
AIRMASS FOR THE WEEKEND.
UPPER LEVEL LOW OVER SOUTHERN CANADA WILL APPROACH WESTERN ONTARIO
TUESDAY MORNING. SEVERAL WEAK SHORTWAVES TRACKING THROUGH THE
LONGWAVE TROUGH AND HEIGHT FALLS ASSOCIATED WITH THE LOW WILL
CONTINUE TO BREAK DOWN THE RIDGE OVER THE EASTERN CONUS. THE FRONT
WILL BE DRAPED ACROSS MID MI BY TUESDAY MORNING WITH THE
PRECIPITATION EVENT WELL ON ITS WAY. A SHORTWAVE IS PROGGED TO LIFT
ALONG THE FRONT EARLY TUESDAY WHICH WILL DEVELOP A SFC LOW NEAR
IOWA. THIS WILL LIFT THE FRONT BACK NORTHWARD TEMPORARILY AS A WARM
FRONT...KEEPING THE HIGHEST POPS ACROSS THE SAGINAW VALLEY. THIS SFC
LOW WILL LIFT NE THROUGH MID MI TUESDAY EVENING WHICH WILL SIGNAL
THE START OF A MORE PROGRESSIVE SYSTEM OVERALL OWNING TO A STRONG
UPPER JET MAX COMING ASHORE BRITISH COLUMBIA MONDAY NIGHT AND
SURGING AROUND THE UPPER LOW. THIS WILL FORCE THE COLD FRONT ACROSS
LOWER MI LATE TUESDAY NIGHT INTO WEDNESDAY MORNING. THIS SYSTEM
OVERALL WILL BE A VERY EFFICIENT RAIN MAKER AS PWATS LOOK TO HOVER
JUST SHY OF 2 INCHES THROUGH THE DURATION OF THE EVENT. STEADY AND
STRONG 850MB LL JET WILL CONTINUALLY FEED MOISTURE NORTHWARD AHEAD
OF THE FRONT. IMPRESSIVE LL THETA E FIELD AS WELL WITH AN ENHANCED
RIBBON OF WARM/MOIST AIR JUST SITTING OVER THE STATE. INSTABILITY
WILL NOT BE TOO GREAT BUT A TALL SKINNY CAPE PROFILE WOULD FAVOR
HEAVY RAINFALL. POPS WILL BE DEPENDENT ON SHORTWAVE
ACTIVITY...PULSES IN THE LL JET...AND FLUCTUATIONS IN THE FRONTAL
BOUNDARY SO GENERALLY SPEAKING...LIKELYS WILL BE FEATURES ACROSS THE
NORTH WITH CHANCE POPS FURTHER SOUTH WITH FUTURE UPDATES PEGGING THE
SMALLER SCALE FORCINGS. SHOWERS WILL DOMINATE BUT SOME
ISOLATED/EMBEDDED THUNDERSTORMS CANNOT BE RULED OUT. BEST CHANCES
FOR THUNDERSTORMS WILL BE WITH THE ACTUAL FROPA WEDNESDAY MORNING.
TEMPERATURES WILL BE TRICKY TUESDAY AS THE FRONTAL LOCATION AND
EXCESSIVE CLOUDS ACROSS THE NORTH WILL LIKELY LEAD TO A HEALTHY
GRADIENT ACROSS SE MI. SHOULD STILL BE ABLE TO GET INTO THE
MID/UPPER 80S ACROSS THE SOUTH AND DETROIT METRO WITH ONGOING
SHOWERS AND CLOUDS KEEPING LOCATIONS FURTHER NORTH CLOSER TO 80 OR
EVEN IN THE UPPER 70S.
PASSAGE OF THE COLD FRONT WILL BRING ABOUT SOME NOTABLE CHANGES
FOR THE REMAINDER OF THE LONG TERM. MUCH COOLER AND DRIER AIR WILL
FEED INTO THE AREA WITH NORTHERLY FLOW. A WAVE DIVING INTO THE BASE
OF THE LONGWAVE TROUGH WILL THEN DEEPEN AND CUTOFF AS IT REACHES THE
GREAT LAKES FOR THE WEEKEND. 850MB TEMPS ARE FORECAST TO FALL BACK
INTO THE SINGLE DIGITS WITH HIGH TEMPERATURES IN THE LOW 70S...AND
POSSIBLY THE UPPER 60S FRIDAY AND SATURDAY. SHOWERS WILL BE POSSIBLE
STARTING FRIDAY NIGHT ASSOCIATED WITH THE BROAD LIFT FROM THE UPPER
LEVEL LOW AND ANY SFC PRESSURE FALLS WITH IT.
MARINE...
SOUTHWESTERLY WINDS WILL BECOME TODAY AHEAD OF AN APPROACHING FRONT.
THIS SLOW MOVING FRONT WILL BRING A CHANCE OF SHOWERS THIS MORNING
FOR NORTHERN LAKE HURON AND LATER THIS AFTERNOON FURTHER SOUTH. A
THUNDERSTORM CANNOT BE RULES OUT BUT NOT EXPECTING ANYTHING STRONG
OR WIDESPREAD. A SURFACE LOW WILL THEN TRACK THROUGH THE AREA LATE
TUESDAY...BRINGING ADDITIONAL SHOWERS AND THUNDERSTORMS THROUGH
EARLY WEDNESDAY. A PERIOD OF GUSTY SOUTHWEST WINDS WILL BE POSSIBLE
ON TUESDAY AS THIS LOW PASSES THROUGH NORTHERN LOWER MICHIGAN. THIS
WILL BE ESPECIALLY TRUE OVER SAGINAW BAY DUE TO FUNNELING.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....SF
UPDATE.......SF
SHORT TERM...JVC
LONG TERM....DRK
MARINE.......DRK
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1142 AM EDT MON SEP 7 2015
LATEST UPDATE...
HYDRO
.SYNOPSIS...
ISSUED AT 318 AM EDT MON SEP 7 2015
THE HOLIDAY WEEKEND WILL COME TO A RATHER WET CLOSE AS A SLOW
MOVING FRONTAL SYSTEM STALLS OVER THE AREA TONIGHT INTO TUESDAY
BEFORE FINALLY CLEARING THE AREA BY MID MORNING WEDNESDAY. MOST OF
THE AREA WILL HAVE A WARM START TO THE DAY DAY WITH SOME SUNSHINE
BUT SHOWERS AND THUNDERSTORMS WILL OVERSPREAD THE AREA FROM
NORTHWEST TO SOUTHEAST BY LATE AFTERNOON. ALL AREAS WILL SEE
PERIODS OF SHOWERS AND THUNDERSTORMS TONIGHT INTO WEDNESDAY
MORNING. RAINFALL WILL BE HEAVY AT TIMES. COOLER AND DRY WEATHER
FOLLOWS LATER WEDNESDAY INTO THURSDAY. YET ANOTHER STORM COULD
MEAN A WET WEEKEND BUT THAT WILL DEPEND ON THE STORMS TRACK.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 318 AM EDT MON SEP 7 2015
MUCH HAS BEEN WRITTEN ABOUT THE RAINFALL POTENTIAL FOR TONIGHT
INTO WEDNESDAY MORNING IN ALL OF OUR DISCUSSIONS FOR AT LEAST 4
DAYS NOW AND LITTLE HAS CHANGED. EXPECT A HEAVY RAINFALL EVENT
OVER MOST OF THE AREA TONIGHT INTO WEDNESDAY MORNING. THE EXACT
AXIS OF THE HEAVIEST RAINFALL IS UNCERTAIN AT THIS TIME BUT IT
WOULD SEEM THE BEST GUESS IS CURRENTLY NORTH OF A LINE FROM SOUTH
HAVEN TO ALMA. I WOULD EXPECT SOME LOCALIZED RAINFALL AMOUNTS
COULD EXCEEDED 5 INCHES FROM THIS EVENT SO LOCALIZED FLOODING
WOULD BE AN ISSUE.
THE PRECIPITABLE WATER VALUES RISE TO NEAR 2 INCHES BY LATE
AFTERNOON OVER OUR CENTRAL CWA AND REMAIN IN PLACE UNTIL THE COLD
FRONT FINALLY CLEARS THE AREA WHEN THE SECOND UPPER WAVE MOVES
THROUGH THE AREA WEDNESDAY MORNING. THIS IS A 1 DAY IN 5 TO 10
YEAR SORT OF EVENT FOR SOUTHWEST LOWER MICHIGAN. CLEARLY SOMETHING
WE WILL NEED TO MONITOR.
THE CONVECTION OVER WISCONSIN AND LAKE MICHIGAN WILL WEAKEN SOME
AS IT MOVES INTO OUR CWA THIS MORNING BUT WILL RE-FIRE THIS
AFTERNOON AS THE DEEP MOISTURE MOVES OVERHEAD. THE FIRST PRIMARY
UPPER WAVE WILL START THE MAIN EVENT LATER TONIGHT AND THAT WILL
LAST INTO TUESDAY MORNING. THE SECOND UPPER WAVE WILL ENHANCE
ACTIVITY TUESDAY EVENING INTO WEDNESDAY MORNING.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 318 AM EDT MON SEP 7 2015
A COLD FRONT SHOULD BE JUST SOUTH OF THE CWA WEDNESDAY NIGHT AND
COOLER AIR WILL BE MOVING INTO LOWER MICHIGAN COURTESY OF A DEEP
UPPER TROUGH THAT DEVELOPS BY THE END OF THE WEEK. HIGHS IN THE 60S
ARE EXPECTED FRIDAY AND SATURDAY. THE UPPER TROUGH WILL ALSO RESULT
IN SOME SHOWERS THURSDAY NIGHT AND FRIDAY. THE ECMWF IS QUITE A BIT
DEEPER THAN THE GFS AND CLOSES OFF THE TROUGH INTO A UPPER LOW
WHEREAS THE GFS KEEPS THE SYSTEM AS AN OPEN WAVE. THE GFS SOLUTION
WOULD LIKELY RESULT IN DRIER AND WARMER CONDITONS...BUT STILL MUCH
COOLER THAN WHAT WE HAVE SEEN RECENTLY.
MODEL DIFFERENCES REALLY AFFECT THE END OF THE FORECAST. THE OPEN
WAVE ON THE GFS QUICKLY MOVES EAST ALLOWING TEMPS TO WARM UP BY
THE END OF THE WEEKEND TO AROUND 12C...WHILE THE ECMWF WOULD HOLD
ONTO H8 TEMPS NEAR 7C.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 737 AM EDT MON SEP 7 2015
CURRENTLY ALL TAF SITES ARE VFR AND FOR THE MOST PART THEY SHOULD
STAY THAT WAY THROUGH 08/06Z OR SO. THE MAIN AREA OF CONVECTION...
MOSTLY JUST SHOWER NOT THUNDERSTORMS...SHOULD MOVE INTO THE TAF
MKG AND GRR TAF SITES IN THE 06Z TO 09Z TIME FRAME. THE SHOWERS
MORE THAN LIKELY WILL NOT REACH THE OTHER TAF SITES BY 08/12Z.
IN THE VERY SHORT TERM...THE SHOWERS/THUNDERSTORMS CLOSE TO THE
MKG TAF SITE SEE WANT TO DISSIPATE BEFORE REACHING MKG. THAT ALSO
AGREES WITH OUR HIGH RESOLUTION MODELS LIKE THE RAP OR HRRR.
&&
.MARINE...
ISSUED AT 345 AM EDT MON SEP 7 2015
THE BEACH HAZARD AND SMALL CRAFT ADVISORIES HAVE BEEN
DISCONTINUED. WE MAY NEED TO REISSUE THESE PRODUCTS WEDNESDAY WHEN
THE COLD AIR COMES BACK INTO THE AREA.
&&
.HYDROLOGY...
ISSUED AT 1142 AM EDT MON SEP 7 2015
WE MAY RUN THE RISK FOR MINOR FLOODING BETWEEN LATE TONIGHT
THROUGH EARLY WEDNESDAY AS HEAVY RAIN IS POISED TO MARCH ACROSS
THE FORECAST AREA.
A SLOW MOVING FRONTAL BOUNDARY WILL BECOME NEARLY STATIONARY LATE
TONIGHT AND DURING THE DAY TUESDAY. FORECAST PRECIPITABLE WATER
VALUES OF AROUND 2.0 INCHES REMAINS UNCHANGED SINCE PRIOR
FORECASTS. TIMING SEEMS TO BE THE MOST CONSISTENT WITH THIS EVENT.
WHILE RAINFALL WILL BE POSSIBLE FROM TONIGHT THROUGH EARLY WEDNESDAY
AFTERNOON...THE HEAVIEST RAIN IS EXPECTED BETWEEN TUESDAY EVENING
AND WEDNESDAY MORNING.
THE ENTIRE FORECAST AREA CAN COUNT ON ABOUT AND INCH OF
PRECIPITATION...WHILE THE HEAVIEST SWATH LANDS NEAR AND NORTH OF
GRAND RAPIDS. 1-3 SEEMS REALISTIC ALONG AND NORTH OF I-96. THE
CATCH HERE IS THAT THE SOUTHERN HALF OF THE FORECAST AREA...SOUTH
OF I-96 REMAINS ENTRENCHED IN THE WARM SECTOR AND COULD EXPERIENCE
HIGHER INSTANTANEOUS RAINFALL RATES. THIS MEANS THAT HEAVY RAINFALL
THAT DEVELOPS IN SOUTHERN SECTIONS OF THE FORECAST AREA...MAY
RESULT IN LOCALIZED HIGHER TOTALS...4-5 INCHES.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...99
AVIATION...WDM
HYDROLOGY...JAM
MARINE...WDM
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1051 AM EDT MON SEP 7 2015
.UPDATE...
THE PROSPECTS FOR SHOWERS/THUNDERSTORMS STILL LOOKS TO BE FAIRLY
LOW/SCATTERED COVERAGE EXPECTED TODAY...AS UPPER LEVEL RIDGE (589
DAM AT 500 MB )IN PLACE IS SLOW TO FLATTEN. SURFACE COLD
FRONT/FOLDING OVER MOISTURE PLUME (PW OF 2 INCHES)/850-700 MB THETA-
E RIDGE AXIS WILL PROVIDE FOCUS FOR ACTIVITY...BUT THE FRONT IS
DISPLACED EAST OF THE UPPER LEVEL FORCING...AS 500 MB TEMPS ACTUALLY
LOOK TO RISE TOWARD -6 C TOWARD 00Z TUESDAY. MID LEVEL LAPSE RATES
(700-500 MB) WILL BE WEAK TODAY...BUT ENOUGH MLCAPE (1000-1500 J/KG)
BUILDING TO MAINTAIN THUNDERSTORM THREAT...BUT 0-6 KM BULK SHEAR
GENERALLY AROUND 20 KNOTS...DOES NOT DRAW A HUGE CONCERN FOR
SEVERE WEATHER...BUT VERY HEAVY RAINFALL IS CERTAINTY EXPECTED
WITH ANY STORM. DEEP LAYER UNIDIRECTIONAL WEST-SOUTHWEST WINDS
SHOULD KEEP CELLS MOVING JUST ENOUGH. 12Z NAM AND LATEST RUC BEING
A BIT MORE GENEROUS WITH COVERAGE OVER NORTH HALF OF THE CWA THIS
AFTERNOON...WITH LITTLE OR NO CAP IN THIS MOIST ENVIRONMENT.
HOWEVER...FORECASTED SURFACE DEW PTS LOOK TO BE A TOUCH TOO
HIGH...BUT STILL MAY DECIDE TO NUDGE POPS UP A JUST A
BIT...DEPENDING ON TREND AND FURTHER ANALYSIS.
TEMPERATURES REMAIN ON TRACK TO REACH INTO THE MID/UPPER 80S...WITH
90 DEGREES LIKELY ACROSS EASTERN AREAS...INCLUDING CITY OF DETROIT.
HIGH BASED CLOUDS SHOULD PROVIDE MODEST RELIEF...BUT CERTAINLY HOT
WITH DEW PTS IN 65 TO 70 DEGREE RANGE. INDICATIVE OF THIS HOT AND
MOIST AIRMASS...FLINT AND SAGINAW COULD SET RECORD HIGH MINIMUM
VALUES FOR TODAY (SEPTEMBER 7). SAGINAW LOW THIS MORNING WAS 73
DEGREES...WITH THE RECORD BEING 71 DEGREES SET IN 1985.
MEANWHILE...FLINT BOTTOMED OUT AT 71 DEGREES...WHICH WOULD TIE THE
RECORD HIGH MINIMUM FOR THE DATE...PREVIOUSLY SET IN 2007.
HOWEVER...STILL HAVE POTENTIAL FOR TEMPERATURES TO DROP TOWARD 70
DEGREES BY MIDNIGHT TONIGHT...ESPECIALLY WITH ANY HELP FROM RAIN
COOLED SHOWERS.
&&
.AVIATION...ISSUED 637 AM EDT MON SEP 7 2015
WIDESPREAD VFR WILL PERSIST UNTIL AT LEAST LATE TONIGHT AS THE LOWER
ATMOSPHERE REMAINS DRY. LONE EXCEPTION MAY BE MBS LATE THIS MORNING
AS SOME DEGREE OF CONVECTIVE REMNANTS ROLL THROUGH BRINGING A HEAVY
SHOWER OR TWO TO THE AIRFIELD. THIS ACTIVITY MAY REIGNITE WITH
DIURNAL HEATING /PERHAPS ALONG REMNANT OUTFLOW/ WARRANTING JUST A
TEMPO FOR HIGHER BASED SHOWERS ATTM. FORCING WILL ORGANIZE NORTH OF
THE DETROIT AREA BRINGING SHOWERS FROM KPTK NORTH BY EARLY TUESDAY
MORNING...BUT BRUNT OF ACTIVITY WILL BE FOCUSED FROM KMBS NORTH.
FOR DTW...CLOUDS MAY BE BRIEFLY SCATTERED AOB 5KFT BEFORE
LIFTING.
//DTW THRESHOLD PROBABILITIES...
* NONE
&&
.PREV DISCUSSION...ISSUED 323 AM EDT MON SEP 7 2015
SHORT TERM...TODAY AND TONIGHT
CONVECTION REMAINS FIRMLY ANCHORED TO ENHANCED SOUTHWESTERLY FLOW
ATTENDANT TO THE LEAD EDGE OF HEIGHT FALLS OVER THE WESTERN AND
NORTHERN GREAT LAKES EARLY THIS MORNING. NWP ADAMANTLY KILL THIS
ACTIVITY DURING THE EARLY MORNING, BUT THETA-E TRANSPORT HAS PROVEN
IMPRESSIVE AND CONVECTION OVER NORTHERN IL/SOUTHERN WI HAS SO FAR
BEEN RESILIENT. THE CORE OF THE LLJ AXIS WITHIN WHICH THIS ACTIVITY
IS EMBEDDED WILL GRADUALLY WEAKEN THROUGH MORNING WHICH DOES SUPPORT
EVENTUAL UPSTREAM DISSIPATION BEFORE THE LLJ FINALLY IMPINGES ON THE
FAR WESTERN CWA AFTER ABOUT 20Z. HOWEVER, DIURNAL HEATING - TEMPERED
BY CONVECTIVE DEBRIS - AND SOME DEGREE OF ONGOING MOISTURE TRANSPORT
WITHIN WEAKER SWLY FLOW OUGHT TO BE SUFFICIENT TO REGENERATE SHOWERS
ALONG THE EASTERN FRINGE OF WHAT REMAINS OF THE ENHANCED
SOUTHWESTERLIES AFTER 18Z. INDEED, PROGGED NAM12 SOUNDINGS DEPICT AN
IMPRESSIVE MOISTENING ABOVE THE LFC WHICH SHOULD HELP GET THINGS
GOING, CONDITIONAL ON SUFFICIENT BOUNDARY LAYER DEEPENING. RECENT
HRRR CYCLES SUPPORT THE IDEA OF REGENERATION AS WELL. LACK OF
INSTABILITY AND SHEAR WILL LIMIT TSTORM POTENTIAL IN GENERAL, BUT
PWATS NEAR 2 INCHES ARE A NOD TO THE PRIMARY THREAT OF HEAVY RAIN
WITH ANYTHING THAT DEVELOPS. THOUGH SENSITIVE TO CONVECTIVE
COVERAGE, HIGHS SHOULD EASILY REACH 90 ACROSS THE FAR EAST, WHILE
THICKER CLOUD COVER EARLIER IN THE DAY IS FORECAST TO LIMIT THE
SAGINAW VALLEY TO THE MID 80S.
RAPID INTENSIFYING OF THE UPPER JET OVER LAKE SUPERIOR WILL ENSUE BY
SEVERAL HOURS AFTER SUNSET MARKING THE ARRIVAL OF MORE VIGOROUS
UPPER ENERGY EMBEDDED WITHIN BROAD CYCLONIC FLOW AROUND THE MANITOBA
CYCLONE. LOWER TROPOSPHERIC FRONTAL ZONE WILL UNDERGO SUBSEQUENT
SHARPENING WHILE A SECONDARY THETA-E SURGE ORGANIZES WITHIN THE
RENEWED LLJ EMERGING OUT OF THE MIDDLE MS VALLEY. THE PRIMARY
UNCERTAINTY DURING THIS TIME IS WHETHER THIS PROCESS WILL ULTIMATELY
SUSTAIN EXISTING/LEFT OVER DIURNAL ACTIVITY OR IF DAYTIME ACTIVITY
WILL WANE COMPLETELY AND GIVE WAY TO SEVERAL HOURS OF DOWN-TIME
BEFORE ISENTROPIC ASCENT RAMPS UP AFTER MIDNIGHT. THIS WILL LIKELY
MAKE ALL THE DIFFERENCE FOR THE DETROIT METRO AREA, AS DISSIPATION
OF DIURNAL ACTIVITY WOULD LIKELY SPELL THE END OF RAIN POTENTIAL FOR
THE EVENING AS FORCING ULTIMATELY REORGANIZES ORGANIZES FURTHER
NORTH ALONG THE M59/I-69 CORRIDOR. CONFIDENCE BY EARLY TUESDAY
MORNING IS HIGHEST IN THE SAGINAW VALLEY WITHIN THE CORRIDOR OF
STRONGEST ASCENT AND DECREASES TOWARD THE THUMB. POPS ARE THEREFORE
TAPERED FROM CATEGORICAL FOR THE FORMER TO ENTRY LEVEL LIKELY FOR
THE LATTER. SKINNY CAPE PROFILE, 2+" PWATS, AND DEVELOPING 12KFT
WARM CLOUD LAYER WILL CERTAINLY SUPPORT AN ENVIRONMENT CAPABLE OF
PROLIFIC HYDROMETEOR PRODUCTION AND RESULTANT HEAVY DOWNPOURS.
ACCORDINGLY, QPF HAS BEEN RAMPED UP TO BASIN AVERAGES OF ABOUT A
HALF INCH AFTER MIDNIGHT. DEPENDING ON COVERAGE, THE POTENTIAL FOR
FURTHER UPWARD ADJUSTMENT WILL EXIST.
LOWS WILL HOVER NEAR 70 FOR YET ANOTHER NIGHT AS HIGH DEWPOINTS PUT
AN A FLOOR ON LOW TEMP POTENTIAL. SOME RELIEF ACROSS THE NORTH WILL
COME IN THE FORM OF RAINFALL, BUT SOUTHERN AREAS WILL REMAIN LARGELY
PRECIP FREE AFTER SUNSET AND WILL BE WARM AND MUGGY ONCE AGAIN.
LONG TERM...
THE LONG TERM WILL FIRST DEAL WITH A LONG DURATION RAINFALL ALONG A
STALLED FRONT...FOLLOWED BY THE INFILTRATION OF A MUCH COOLER
AIRMASS FOR THE WEEKEND.
UPPER LEVEL LOW OVER SOUTHERN CANADA WILL APPROACH WESTERN ONTARIO
TUESDAY MORNING. SEVERAL WEAK SHORTWAVES TRACKING THROUGH THE
LONGWAVE TROUGH AND HEIGHT FALLS ASSOCIATED WITH THE LOW WILL
CONTINUE TO BREAK DOWN THE RIDGE OVER THE EASTERN CONUS. THE FRONT
WILL BE DRAPED ACROSS MID MI BY TUESDAY MORNING WITH THE
PRECIPITATION EVENT WELL ON ITS WAY. A SHORTWAVE IS PROGGED TO LIFT
ALONG THE FRONT EARLY TUESDAY WHICH WILL DEVELOP A SFC LOW NEAR
IOWA. THIS WILL LIFT THE FRONT BACK NORTHWARD TEMPORARILY AS A WARM
FRONT...KEEPING THE HIGHEST POPS ACROSS THE SAGINAW VALLEY. THIS SFC
LOW WILL LIFT NE THROUGH MID MI TUESDAY EVENING WHICH WILL SIGNAL
THE START OF A MORE PROGRESSIVE SYSTEM OVERALL OWNING TO A STRONG
UPPER JET MAX COMING ASHORE BRITISH COLUMBIA MONDAY NIGHT AND
SURGING AROUND THE UPPER LOW. THIS WILL FORCE THE COLD FRONT ACROSS
LOWER MI LATE TUESDAY NIGHT INTO WEDNESDAY MORNING. THIS SYSTEM
OVERALL WILL BE A VERY EFFICIENT RAIN MAKER AS PWATS LOOK TO HOVER
JUST SHY OF 2 INCHES THROUGH THE DURATION OF THE EVENT. STEADY AND
STRONG 850MB LL JET WILL CONTINUALLY FEED MOISTURE NORTHWARD AHEAD
OF THE FRONT. IMPRESSIVE LL THETA E FIELD AS WELL WITH AN ENHANCED
RIBBON OF WARM/MOIST AIR JUST SITTING OVER THE STATE. INSTABILITY
WILL NOT BE TOO GREAT BUT A TALL SKINNY CAPE PROFILE WOULD FAVOR
HEAVY RAINFALL. POPS WILL BE DEPENDENT ON SHORTWAVE
ACTIVITY...PULSES IN THE LL JET...AND FLUCTUATIONS IN THE FRONTAL
BOUNDARY SO GENERALLY SPEAKING...LIKELYS WILL BE FEATURES ACROSS THE
NORTH WITH CHANCE POPS FURTHER SOUTH WITH FUTURE UPDATES PEGGING THE
SMALLER SCALE FORCINGS. SHOWERS WILL DOMINATE BUT SOME
ISOLATED/EMBEDDED THUNDERSTORMS CANNOT BE RULED OUT. BEST CHANCES
FOR THUNDERSTORMS WILL BE WITH THE ACTUAL FROPA WEDNESDAY MORNING.
TEMPERATURES WILL BE TRICKY TUESDAY AS THE FRONTAL LOCATION AND
EXCESSIVE CLOUDS ACROSS THE NORTH WILL LIKELY LEAD TO A HEALTHY
GRADIENT ACROSS SE MI. SHOULD STILL BE ABLE TO GET INTO THE
MID/UPPER 80S ACROSS THE SOUTH AND DETROIT METRO WITH ONGOING
SHOWERS AND CLOUDS KEEPING LOCATIONS FURTHER NORTH CLOSER TO 80 OR
EVEN IN THE UPPER 70S.
PASSAGE OF THE COLD FRONT WILL BRING ABOUT SOME NOTABLE CHANGES
FOR THE REMAINDER OF THE LONG TERM. MUCH COOLER AND DRIER AIR WILL
FEED INTO THE AREA WITH NORTHERLY FLOW. A WAVE DIVING INTO THE BASE
OF THE LONGWAVE TROUGH WILL THEN DEEPEN AND CUTOFF AS IT REACHES THE
GREAT LAKES FOR THE WEEKEND. 850MB TEMPS ARE FORECAST TO FALL BACK
INTO THE SINGLE DIGITS WITH HIGH TEMPERATURES IN THE LOW 70S...AND
POSSIBLY THE UPPER 60S FRIDAY AND SATURDAY. SHOWERS WILL BE POSSIBLE
STARTING FRIDAY NIGHT ASSOCIATED WITH THE BROAD LIFT FROM THE UPPER
LEVEL LOW AND ANY SFC PRESSURE FALLS WITH IT.
MARINE...
SOUTHWESTERLY WINDS WILL BECOME TODAY AHEAD OF AN APPROACHING FRONT.
THIS SLOW MOVING FRONT WILL BRING A CHANCE OF SHOWERS THIS MORNING
FOR NORTHERN LAKE HURON AND LATER THIS AFTERNOON FURTHER SOUTH. A
THUNDERSTORM CANNOT BE RULES OUT BUT NOT EXPECTING ANYTHING STRONG
OR WIDESPREAD. A SURFACE LOW WILL THEN TRACK THROUGH THE AREA LATE
TUESDAY...BRINGING ADDITIONAL SHOWERS AND THUNDERSTORMS THROUGH
EARLY WEDNESDAY. A PERIOD OF GUSTY SOUTHWEST WINDS WILL BE POSSIBLE
ON TUESDAY AS THIS LOW PASSES THROUGH NORTHERN LOWER MICHIGAN. THIS
WILL BE ESPECIALLY TRUE OVER SAGINAW BAY DUE TO FUNNELING.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
UPDATE.......SF
AVIATION.....JVC
SHORT TERM...JVC
LONG TERM....DRK
MARINE.......DRK
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1257 AM EDT MON SEP 7 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 327 PM EDT SUN SEP 6 2015
A SHORTWAVE THAT MOVED THROUGH LAST NIGHT INTO THIS MORNING PRODUCED
HEAVY RAIN OVER WRN LAKE SUPERIOR AND MN...AND EVEN BROUGHT SHOWERS
AND THUNDERSTORMS TO FAR WRN UPPER MI AND ERN LAKE SUPERIOR. OVER
MOST LAND AREAS...AN EML WAS TOO STRONG TO ALLOW CONVECTION TO
CONDITIONS...WITH ONLY A FEW DROPS HAVING FALLEN AT WFO MQT TODAY AS
A ROGUE SHOWER PASSED BY. CLOUD COVER HAS BEEN MORE EXTENSIVE DUE TO
THE MORNING CONVECTION...AS WELL AS CONVECTION UPSTREAM OVER WI THAT
HAS SENT HIGH CLOUDS OVER MUCH OF THE AREA. THIS HAS BROUGHT DOWN
MAX TEMPS A FEW DEGREES FROM WHAT WAS PREVIOUSLY EXPECTED.
STILL...MUGGY CONDITIONS PERSIST AS LOW-MID 80S TEMPS AND LOW 70S
DEW POINTS ARE BEING OBSERVED.
MODELS HAVE NOT PERFORMED WELL ALL DAY...EVEN THE HRRR HAS CONTINUED
TO INITIALIZE WITH HEAVY PRECIP OVER WRN UPPER MI WHERE NON EXISTS.
THIS SEEMS LIKELY DUE TO AN UNDERESTIMATION OF BOTH THE STRENGTH OF
THE EML/CIN AND POOR HANDLING OF MORNING PRECIP/CLOUD COVER. LATEST
RUNS OVER MANY HIGH-RES MODELS ARE NOW DOING A DECENT JOB WITH QPF
OVER THE CWA AT THE PRESENT...BUT ARE VERY POOR IN THEIR HANDLING OF
UPSTREAM CONVECTION OVER NERN MN (ASSOCIATED WITH A COLD FRONT
MOVING SE) AND CONVECTION OVER WRN WI AND SOUTH MN AHEAD OF A
SHORTWAVE AND WEAK SFC LOW NEAR THE MN/SD BORDER. THE HRRR IS
HANDLING UPSTREAM CONVECTION WELL...AND IT ALSO IS SIMILAR TO THE
OTHER MODELS BY TIME THE NEXT ROUND OF CONVECTION MOVES IN MAINLY
AFTER 00Z THIS EVENING. THIS LENDS GREATER CONFIDENCE TO OTHER
MODELS...SO WILL USE THEN SINCE THEY ALSO ARE DOING WELL NOW. MAIN
MODELS USED ARE THE NAM...NAM DNG...REGIONAL GEM...NCEP HIGH-RES WRF
ARW AND NMM. SHOWERS AND THUNDERSTORMS WILL MOVE IN AFTER 00Z THIS
EVENING AS THE SHORTWAVE EJECTS INTO THE AREA AND THE SFC LOW MOVES
THROUGH THE N...DRIVING THE COLD FRONT THROUGH. HEAVY RAIN IS
EXPECTED IN ANY THUNDERSTORMS DUE TO WELL ABOVE NORMAL
MOISTURE/PWATS. OTHER THREATS ARE POSSIBLY LARGE HAIL AND DAMAGING
WINDS...MAINLY OVER THE W. MUCAPES OF 1000-1500J/KG (MAINLY THIS
HIGH OVER THE W) AND 0-6KM BULK SHEAR AROUND 30 ARE MARGINAL
VALUES...SO SOME STRONG TO SEVERE STORMS ARE POSSIBLE OVER THE
W...BUT NOT LIKELY.
STILL SOME UNCERTAINTY MON. MODELS GENERALLY AGREE THAT MOST OF THE
PRECIP WILL BE E OF THE CWA BY 18Z...EXCEPT MAYBE A COUPLE NUISANCE
SHOWERS OVER THE E. HOWEVER...THE NAM AND NCEP HIGH-RES WRF NMM ARE
SHOWING CONVECTION BREAKING OUT IN THE AFTERNOON OVER ERN UPPER MI.
HOWEVER...DID NOT INCORPORATE THAT INTO THE FORECAST AT THIS TIME AS
THOSE MODELS SEEM TO BE OVERDOING SFC TEMPS AND INSTABILITY. SKIES
SHOULD CLEARING FROM THE W...LAGGING THE LONGEST OVER THE E NEAR
LAKE SUPERIOR. HIGHS SHOULD BE IN THE 70S TO AROUND 80...WARMEST FAR
SOUTH CENTRAL.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 449 PM EDT SUN SEP 6 2015
MONDAY NIGHT THROUGH TUESDAY...THE GFS AND ECMWF WERE IN RELATIVELY
GOOD AGREEMENT WITH THE STRENGTH/POSITION OF THE SHORTWAVE MOVING
OUT OF THE PLAINS TOWARD THE GREAT LAKES THAT SUPPORTS DEVELOPMENT
OF A SFC WAVE ALONG THE FRONT. WITH MOST OF THE PCPN TO THE SOUTH OF
THE CWA...CHANCE POPS WERE MAINTAINED FOR THE SE HALF...ESPECIALLY
ALONG LAKE MICHIGAN.
TUE NIGHT INTO WED...HIGH PRES WILL BUILD INTO THE WRN LAKES TUE
NIGHT INTO WED WITH CLEARING SKIES. LOOK FOR TEMPS NEAR SEASONAL
AVERAGES WITH LOWS AROUND 50 TO 55 AND HIGHS AROUND 70.
THU-FRI...THE GFS/GEFS/ECMWF REMAIN IN RELATIVELY GOOD AGREEMENT
WITH THE SHORTWAVE TROUGH DIGGING TOWARD THE UPPER MS VALLEY WED
NIGHT AND THROUGH THE NRN LAKES THU. ELEVATED INSTABILITY MAY BE
MARGINAL FOR TSRA...BUT WITH MODERATE TO STRONG DEEP LAYER QVECTOR
CONV AND FAVORABLE MOISTURE TRANSPORT...AT LEAST ISOLD TS WILL BE
POSSIBLE. THE 12Z ECMWF HAS TRENDED BACK TOWARD A DEEPER TROUGH INTO
THE GREAT LAKES BY FRI WITH DEEP MOISTURE AND NRLY CYCLONIC FLOW
THAT WOULD SUPPORT SHOWERS AND LAKE ENHANCED RAIN INTO UPPER MI.
EVEN THOUGH GFS IS MORE PROGRESSIVE AND NOT AS DEEP WITH THE
TROUGH...850 MB TEMPS TO AROUND 2C (LAKE TEMPS AROUND 15C) MAY STILL
BE COLD ENOUGH TO PRODUCE SOME LAKE EFFECT PCPN. MORE FALL-LIKE
CONDITIONS ARE EXPECTED WITH HIGHS ONLY IN THE UPPER 50S AND LOWER
60S FRI.
SAT-SUN...ALTHOUGH A TRANSITION BACK TOWARD A MORE ZONAL PATTERN IS
EXPECTED WITH MODERATING TEMPS SAT...THERE IS UNCERTAINTY WITH THE
AMOUNT OF HEIGHT FALLS INTO THE NRN CONUS ASSOCIATED WITH A
SHORTWAVE MOVING TOWARD HUDSON BAY OR NW ONTARIO. THE 12Z/6
ECMWF...UNLIKE THE DRY GFS AND 00Z/6 ECMWF DROPS A SHORTWAVE AND
FRONT WITH PCPN INTO THE NRN LAKES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1257 AM EDT MON SEP 7 2015
SHRA/TSRA...SOME WITH VERY HEAVY RAINFALL...WILL CONTINUE TO SPREAD
E ACROSS THE AREA OVERNIGHT IN ASSOCIATION WITH A COLD FRONT.
PRECIPITION WILL BE ENDING AT KIWD/KCMX IN THE NEXT FEW HRS...WHILE
HEAVIER PCPN WILL AFFECT KSAW FOR THE NEXT COUPLE OF HRS. EXPECT
IFR/LIFR CONDITIONS TO DEVELOP AT KIWD/KCMX DURING THE NIGHT...WITH
KSAW FALLING TO LIFR AROUND SUNRISE. IMPROVEMENT TO VFR WILL OCCUR
FROM W TO E AT ALL TERMINALS FROM LATE MORNING THRU MID AFTN AS
DRIER AIR ARRIVES BEHIND COLD FRONT.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 327 PM EDT SUN SEP 6 2015
FOG WILL REMAIN A CONCERN UNTIL THE FRONTAL PASSAGE LATE TONIGHT AS
HIGH DEW POINTS KEEP MOVING ACROSS THE COLDER WATER. SOUTH WINDS
TODAY WILL TURN WESTERLY ON MONDAY THEN DECREASE MON NIGHT INTO TUE.
OVERALL...NEXT WEEK LOOKS FAIRLY QUIET ON THE LAKE WITH NO MAJOR
SYSTEMS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...TITUS
LONG TERM...JLB
AVIATION...ROLFSON
MARINE...TITUS
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
909 PM CDT TUE SEP 8 2015
.UPDATE:
Issued at 850 PM CDT Tue Sep 8 2015
Have updated forecast to pull precip further S as cdfnt continues
to slowly move swd. Precip along the fnt shud fill in a little
more to the E over night. Overall, have trended twd the RAP soln
which keeps most of the precip across sern portions of the CWA by
sunrise Wed morning.
&&
.SHORT TERM: (Through Late Tonight)
Issued at 210 PM CDT Tue Sep 8 2015
Cold front really struggling to make too much progress south today
and is currenlty aligned from near Kansas City to the Quad Cities.
Precipitation trends remain the focus for the forecast.
Area of showers and thunderstorms continue to slowly progress south
on outflow from last nights convection that occurred to our
northwest. This is well out ahead of the front and away from any
deep layer flow aloft so severe chances have been largely removed.
More convection is forming back across central Kansas and think this
wave of precipitation will replace ongoing activity overnight and
into tomorrow morning.
CVKING
.LONG TERM: (Wednesday through Next Tuesday)
Issued at 210 PM CDT Tue Sep 8 2015
Upper level trof axis, currently extending from the upper Midwest
to the central Plains, will move east over the next 24 hours
forcing the cold front south through the area and ending the
threat of precipiation from northwest to southeast.
Temperatures should cool to near normal values Wednesday and
Thursday before a stronger cold front arrives Thursday night and
Firday. Have some chance PoPs with the front, but think focus may
remain west of the CWA. Autumn temperatures arrive for the weekend
with highs in the 70s and lows dipping into the upper 40s and lower
50s.
CVKING
&&
.AVIATION: (For the 00z TAFs through 00z Wednesday Evening)
Issued at 652 PM CDT Tue Sep 8 2015
Cold front is thru KUIN and will slowly push southeastward
tonight, getting thru KCOU later this evening and STL metro sites
overnight. SHRA/TSRA trying to fire along it and should eventually
fill in later this evening but by this time should also be limited
with any thunder. While with early passage of cold front thru
KUIN, that should spare them much in the way of low CIGs, low CIGs
currently only near the front should expand in coverage tonight
and linger, especially over the STL metro sites. It is also here
at the STL metro sites where there will be the best potential for
IFR CIGs and will be monitored closely for possible amendments.
Clouds that do form will be slow to pull out, with non-VFR CIGs
expected well into the day Wednesday with diurnal enhancements as
it becomes more of a broken cumulus cloud field. Eventually
clearing is anticipated by Wednesday evening. Winds will be light
throughout, becoming northerly behind front.
Specifics for KSTL: VFR conditions will transition to MVFR with
rain filling in later this evening. IFR possible late tonight into
Wednesday morning, but will forego mention and monitor for
possible amendment later this evening. Otherwise, non-VFR CIGs
slow to pull out until mid-late Wednesday afternoon thanks to
diurnal enhancements to cloud field but eventually, a return to
VFR conditions is expected by nightfall Wednesday night.
TES
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
1120 PM MDT SUN SEP 6 2015
AVIATION SECTION UPDATED.
.DISCUSSION...
UPDATE FORTHCOMING. MODELS, INCLUDING HRRR AND RAP13,
ALL BEING SOME LIGHT PRECIPITATION OFF THE ROCKY MOUNTAIN FRONT AND
OUT OVER THE PLAINS AFTER 06Z AS WEAK SHORT WAVE ENERGY MOVES
THROUGH. HAVE ADDED LOW POPS FOR AFOREMENTIONED AREA FOR THIS
REASON. REMAINDER OF FORECAST LOOKS GOOD AS DO OVERNIGHT LOWS.
&&
.AVIATION...
UPDATED 2320Z.
WESTERLY FLOW ALOFT WILL CONTINUE TO BRING MID AND HIGH CLOUDS
ACROSS THE AREA. WINDS HAVE DROPPED TO LIGHT AND VARIABLE AT MOST
TERMINALS TONIGHT...BUT WEST WIND GUSTS TO AROUND 25KTS WILL
REDEVELOP MONDAY. VFR CONDITIONS PREVAIL.
&&
.PREV DISCUSSION...ISSUED 241 PM MDT SUN SEP 6 2015
TONIGHT THROUGH TUESDAY...GUSTY WESTERLY WINDS AFFECTING THE
FORECAST AREA THIS AFTERNOON WILL DIMINISH DURING THE EARLY TO MID
EVENING HOURS. WEST TO NORTHWEST CYCLONICALLY-CURVED FLOW ALOFT
WILL PREVAIL FOR MONDAY AND TUESDAY WITH AFTERNOON HIGH
TEMPERATURES REMAINING BELOW SEASONAL AVERAGES. SEVERAL SHORTWAVES
MOVING THROUGH THE FLOW ALOFT WILL BRING SCATTERED SHOWERS TO THE
MOUNTAINS OF THE CONTINENTAL DIVIDE AND GLACIER PARK, BUT ONLY
ISOLATED LIGHT RAIN SHOWERS ARE EXPECTED IN THE PLAINS AND
VALLEYS. WINDS REMAIN WESTERLY AND BREEZY BUT ARE NOT EXPECTED TO
BE AS STRONG AS THOSE OF TODAY. MPJ
TUESDAY NIGHT THROUGH SUNDAY...LITTLE IF ANY SIGNIFICANT WEATHER
EXPECTED DURING THIS PERIOD. ONLY WEATHER SYSTEM OF NOTE IS A
QUICK- MOVING SHORTWAVE TROF THAT WILL PRODUCE SOME SCATTERED
LIGHT RAIN SHOWERS THROUGH CENTRAL MT THROUGH TUES NIGHT. ALSO,
RESIDUAL MOISTURE FROM THIS SYSTEM MAY COMBINE WITH NORTHWEST FLOW
ALOFT TO GENERATE A FEW SHOWERS AND A THUNDERSTORM OR TWO OVER THE
LITTLE BELT AND SNOWY MTNS ON WED AFTN/EVE WHILE REST OF REGION
REMAINS DRY. FROM LATE WED ONWARD, HIGH PRESSURE RIDGING WILL
SLOWLY BUILD INTO THE NORTHERN ROCKIES, MAINTAINING THE DRY
CONDITIONS THROUGH AT LEAST SATURDAY. LATEST FORECAST MODEL RUNS
SHOW THE NORTHERN PORTION OF THE RIDGE WEAKENING ON SUNDAY IN
RESPONSE TO AN UPPER- LEVEL TROF MOVING THROUGH WESTERN CANADA.
HOWEVER, ONLY LIMITED MOISTURE MAKES IT SOUTH OF THE US/CAN
BORDER, PERHAPS ENOUGH TO DEVELOP A FEW SHOWERS ALONG THE ROCKY
MTN FRONT, BUT DOWNSLOPE FLOW SHOULD KEEP PRECIPITATION FROM
FORMING OVER THE PLAINS. AS THE RIDGE MOVES INTO OUR REGION, WE`LL
SEE A GRADUALLY WARMING TREND WITH LOW 70S ON THURS INCREASING TO
THE LOW 80S FOR SAT. 12Z FORECAST MODELS INDICATE THE POTENTIAL
FOR A DISTURBANCE WITH AN ASSOCIATED COLD FRONT TO MOVE THROUGH
THE FORECAST AREA ON SUNDAY, BUT THERE IS SOME DISCREPANCY WITH
REGARDS TO STRENGTH. HAVE THEREFORE ADDED MENTION OF SHOWERS AND
HAVE COOLED SUNDAY`S HIGHS AROUND 5 DEGREES TO ACCOUNT FOR THIS.
WARANAUSKAS/COULSTON
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 43 62 42 67 / 10 10 10 10
CTB 40 60 42 64 / 10 20 10 10
HLN 42 64 40 68 / 10 10 20 0
BZN 37 63 36 70 / 0 0 20 0
WEY 23 59 23 62 / 0 0 10 0
DLN 35 62 35 69 / 0 0 10 0
HVR 39 62 41 67 / 10 10 10 10
LWT 41 60 39 68 / 10 10 10 0
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
WEATHER.GOV/GREATFALLS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
336 PM CDT MON SEP 7 2015
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 335 PM CDT MON SEP 7 2015
SHORTWAVE ALOFT IS EVIDENT ON WATER VAPOR ACROSS THE CENTRAL
ROCKIES. THIS WILL MOVE EAST-NORTHEASTWARD ACROSS THE CENTRAL PLAINS
THE NEXT 12 TO 24 HOURS. THUNDERSTORMS STILL ARE POSSIBLE TONIGHT.
THINKING IS THAT STORMS WILL DEVELOP THIS AFTERNOON OVER THE HIGHER
TERRAIN ACROSS COLORADO AHEAD OF THE SHORTWAVE. EXPECTING THAT
STORMS WILL THEN MOVE EAST-NORTHEAST ACROSS MUCH OF THE AREA THIS
EVENING. NOT EVERYONE WILL SEE RAIN...BUT A FAIRLY DECENT COVERAGE
OF STORMS IS POSSIBLE DUE TO FAVORABLE JET DYNAMICS. SEVERE THREAT
IS NOT GREAT DUE TO PERSISTENT CLOUD COVER THAT HAS REMAINED INTACT
AND HAS CUT DOWN ON THE AMOUNT OF INSTABILITY PRESENT ACROSS MUCH OF
THE AREA. BUT...WITH PLENTY OF SHEAR PRESENT...CAN/T RULE OUT A FEW
STRONG OR PERHAPS A SEVERE THUNDERSTORM.
OTHERWISE A COLD FRONT WILL MOVE SOUTHEAST THROUGH THE AREA LATER
TONIGHT USHERING IN COOLER AIR FOR TUESDAY...WITH HIGHS IN THE MID
TO UPPER 70S ACROSS THE AREA. SOME LINGERING MID LEVEL INSTABILITY
WILL BE PRESENT THROUGH TUESDAY MORNING...AND SOME LIFT WILL
CONTINUE THROUGH MIDDAY BEFORE JET DYNAMICS WANE...SO WILL CONTINUE
THE SLIGHT CHANCE FOR SOME MID LEVEL TYPE SHOWER/ISOLATED
THUNDERSTORM ACTIVITY.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 335 PM CDT MON SEP 7 2015
IN THE NEAR TERM TODAY NAM WAS BY FAR THE BEST AT HANDLING ONGOING
PRECIPITATION. LONG RANGE MODELS WERE SLOWER WITH SOLUTIONS IN THE
NEAR TERM. WILL TREND THE FORECAST IN THE MID TERM TOWARDS THE NAM
SOLUTIONS AND A BLEND OF GFS AND ECMWF FOR THE EXTENDED WITH BIAS
TOWARDS WARMER GFS SOLUTIONS AS ECMWF BRINGS A TROUGH AND SUBSEQUENT
CUTOFF LOW INTO THE GREAT LAKES REGION AND AT THE SAME TIME SHEARING
THE HUDSON BAY LOW TO THE NORTHEAST. GFS BRINGS A BROAD TROUGH INTO
THE EASTERN CONUS WHICH SEEMS MORE REASONABLE FOR THE SEASON.
EXTENDED MODELS HAVE BEEN TRYING TO BRING COOLER AIR INTO NORTHERN
PLAINS SINCE LAST WEEK AND HAVE CONTINUED TO TREND UP WITH LATER
RUNS.
TUESDAY EVENING LIGHT SOUTHEAST FLOW AND SURFACE HIGH PRESSURE OVER
HEAD AND FRONT WELL TO THE SOUTH OVER SOUTHERN KANSAS...POSSIBILITY
FOR SOME LIGHT FOG TOWARDS SUNRISE AS TEMPERATURE DEWPOINT SPREAD
DECREASES. HAVE LEFT OUT FOR NOW. WILL TAKE A LOOK ON THE OVER NIGHT
SHIFT TONIGHT WHEN I COME BACK IN. LOWS AROUND 50. SURFACE TROUGH
BUILDS ALONG THE FRONT RANGE ON WEDNESDAY WITH SOUTHWEST FLOW AND
DECENT WAA TEMPERATURES WILL RISE INTO THE LOWER 80S. 25KT 850MB LLJ
WITH MID LEVEL FORCING ALONG THE TROUGH AXIS COULD PRODUCE SOME
ISOLATED CONVECTION THROUGH THE LATE AFTERNOON AND MOVING EAST INTO
THE EVENING AS LLJ INCREASES TO AROUND 50KTS. SOMEWHAT COOLER ON
THURSDAY AS SURFACE HIGH PRESSURE BUILDS INTO WESTERN NEBRASKA.
MODELS FORMING A WEAK SURFACE LOW ALONG STATIONARY BOUNDARY OVER
NORTHWEST KANSAS THROUGH THE DAY FRIDAY INTO SATURDAY MORNING. UPPER
WAVE DROPPING A WAVE THROUGH THE NORTHERN PLAINS AS THE SURFACE LOW
MOVES SOUTHEAST INTO SOUTH CENTRAL KANSAS WITH THE FRONT. SOUTHEAST
ZONES MAY SEE SOME PRECIPITATION BUT WITH THE SURFACE LOW AND THE
FRONT MOVING SOUTHEAST HAVE RETAINED SCHC AFTER MIDNIGHT. RIDGE AND
WARMER AIR BUILDS EAST INTO WESTERN NEBRASKA SATURDAY SUNDAY AND
MONDAY. HIGHS CLIMBING INTO THE MID 80S AND DRY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1248 PM CDT MON SEP 7 2015
VERY DIFFICULT AVIATION FORECAST OVER THE NEXT 24 HOURS FOR THE KLBF
AND KVTN TERMINALS. THE FIRST AREA OF CONCERN/DIFFICULTY IS THE
PERSISTENCE OF LOW CLOUDS OVER THE KLBF TERMINAL...WITH CURRENT
THINKING THAT MVFR CONDITIONS WILL CONTINUE THROUGH THE AFTERNOON
HOURS TODAY. THIS CURRENT THINKING IS SUPPORTED BY THE LATEST RUNS
OF THE RAP/NAM/AND HRRR MODELS...WHICH KEEP CEILINGS AT OR BELOW
3000FT THROUGH 02Z. THE NEXT AREA OF CONCERN/DIFFICULTY WILL BE THE
TIMING ON AFTERNOON/LATE EVENING CONVECTION WITHIN THE GENERAL
VICINITY OF THE KLBF AND KVTN TERMINALS. LATEST OPERATIONAL HRRR HAS
A LINE OF STORMS MOVING INTO THE SOUTHEASTERN PANHANDLE OF NEBRASKA
AND SOUTHWESTERN NEBRASKA BY 00Z THIS EVENING...AND THEN MOVING INTO
THE KLBF TERMINAL BETWEEN 02Z AND 05Z. A SECOND AREA OF CONVECTION
IS ALSO ANTICIPATED TO FORM OVER NORTHWESTERN NEBRASKA BETWEEN 21Z
AND 23Z...BEFORE MOVING EAST INTO THE KVTN TERMINAL BETWEEN 01Z AND
04Z. UNCERTAINTY DOES EXIST WITH SPATIAL COVERAGE OF THIS SECOND
AREA OF CONVECTION NEAR KVTN...HOWEVER...CURRENT CLEARING OVER
NORTHWESTERN NEBRASKA WOULD SUPPORT THE DEVELOPMENT OF THUNDERSTORMS
THIS AFTERNOON.
ANOTHER ROUND OF LOW CLOUDS ARE POSSIBLE TONIGHT AGAIN OVER THE KLBF
TERMINAL AFTER THE AREA OF SHOWERS/THUNDERSTORMS MOVES THROUGH
THIS EVENING. CONFIDENCE IS HIGH ENOUGH AT THIS TIME TO BRING
BACK IN MVFR CONDITIONS OVER THE KLBF TERMINAL...WITH EVEN THE
CHANCE FOR SOME DRIZZLE AFTER 09Z...HOWEVER...THIS WILL BE HIGHLY
DEPENDENT ON HOW MUCH MIXING (WHICH WOULD TEND TO SCOUR OUT THE
MOISTURE) OCCURS IN THE ATMOSPHERE ONCE THIS EVENINGS STORMS MOVE
THROUGH.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...TAYLOR
LONG TERM...POWER
AVIATION...MOLDAN
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1248 PM CDT MON SEP 7 2015
.SYNOPSIS...
ISSUED AT 356 AM CDT MON SEP 7 2015
LARGE UPPER LOW LOCATED OVER SRN CANADA WITH TROUGH AXIS SWD INTO
MT AND ID...WITH NOTABLE PV ANOMALY MOVING THROUGH THE BASE OF
THE TROUGH OVER NRN NV. ZONE OF HIGHER SWRLY FLOW ALOFT LOCATED
AHEAD OF THIS UPPER TROUGH FROM MN TO SRN CA...RUNNING THROUGH
THE NWRN CORNER OF NEB. ALONG THIS SWRLY FLOW ALOFT...WEAK SHORT
WAVES CONTINUE TO PROGRESS QUICKLY NEWD AS THEY HAVE THE PAST FEW
DAYS. SFC FRONT THAT MOVED THROUGH THE AREA THIS MORNING LOCATED
FROM SRN IA ACROSS NERN KS SWWD TO NEAR DDC. THIS FRONT MARKED BY
CONVECTION FROM SRN IA INTO NERN KS. ON THE NORTH SIDE OF THIS
FRONT...ERLY UPSLOPE FLOW EXISTS AT THE SFC WITH NERLY WIND AT
500M/1KM AT KLNX. SFC WINDS HAVE TURNED SERLY ALREADY FROM THE
PANHANDLE INTO NWRN KS AND THIS IS CONTRIBUTING TO TSRA
DEVELOPMENT ACROSS WRN NEB. VSBYS STARTING TO BE REDUCED IN THE
ONL AREA DUE TO FOG.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 356 AM CDT MON SEP 7 2015
FOR THIS MORNING...TSRA DEVELOPING AND MOVING EWD ALONG GRADIENT
OF STEEPER LAPSE RATES ALOFT AND WILL LIKELY BE SUSTAINED AS
ELEVATED INSTABILITY EXPANDS EWD IN INCREASING ISENTROPIC
UPGLIDE. CIRA LOW CLOUD/FOG PRODUCT SHOWING ONLY LIMITED
DEVELOPMENT OF LOW CLOUDS AS EXPECTED BY SHORT RANGE MODELS AND
SREF PROBABILITY GUIDANCE. WILL CONTINUE THE IDEA OF PATCHY FOG
THOUGH CONVECTIVE TRENDS SO FAR WOULD SUGGEST FURTHER FOG
DEVELOPMENT MAY BE INHIBITED SOMEWHAT.
PREVIOUSLY MENTIONED PV ANOMALY OVER NRN NV WILL CONTINUE TO
ROTATE NEWD TODAY AND AS THE ENTIRE TROUGH PULLS EWD...UPPER
LEVEL JET DEVELOPMENT OCCURS IN CONFLUENT ZONE OVER WY TODAY.
THIS WILL PUT THE RIGHT ENTRANCE REGION OF THE NEWLY DEVELOP JET
STREAK OVER WRN NEB BY AFTERNOON. THE RESULTING DIRECT THERMAL
CIRCULATION THAT IS ALREADY DEVELOPING IN RESPONSE OVER THE HIGH
PLAINS...AS EVIDENCED BY ISENTROPIC LIFT ON THE 310/315K
SFC...WILL INDUCE A NWRLY LOW LEVEL AGEOSTROPHIC FLOW AND ENHANCE
FRONTOGENSIS ACROSS THE WRN PORTION OF THE AREA THIS AFTERNOON.
AS THIS OCCURS IN A REGION OF DECENT MID LEVEL INSTABILITY...NEW
TSRA SHOULD DEVELOP THIS AFTERNOON IN WRN NEB AND MOVE EWD. CAPE
IS NOT EXTREME BUT WITH GOOD SHEAR IN PLACE THROUGH A DEEP LAYER
SOME POTENTIAL FOR LARGE HAIL WILL EXIST WITH ANY STORMS THAT DO
DEVELOP...HENCE THE MARGINAL RISK AS DEPICTED BY SPC. THE FLY IN
THE OINTMENT HERE WOULD BE ONGOING CONVECTION AND CONVECTIVE
DEBRIS THAT REMAIN FROM THIS MORNINGS CONVECTION AND HOW THAT
AFFECTS THE ATMOSPHERE BY THIS AFTERNOON. CLOUD COVER MAY
NEGATIVELY AFFECT THE STORMS BEING ABLE TO REALIZE AVAILABLE
CAPE...BUT LEFT OVER BOUNDARIES MAY BE A FOCUS FOR UPWARD
VERTICAL MOTION ENHANCEMENT TO POSITIVELY INFLUENCE INDIVIDUAL
UPDRAFTS...SO ANOTHER COMPLICATED FCST REMAINS. SHORT RANGE
MODELS AND CAM ENSEMBLES AGAIN SUGGEST A WIDE RANGE OF POSSIBLE
SOLUTIONS. ALTHOUGH THE HRRR HAS HAD ITS STRUGGLES LATELY...THINK
IT MIGHT BE ON TO THE RIGHT IDEA DEVELOPING TSRA IN THE 3-4PM CDT
TIME RANGE. THIS IDEA IS ALSO SUPPORTED BY THE NSSL WRF AND BY A
FEW MEMBERS OF THE NCAR 10 MEMBER 3KM WRF ENSEMBLE. THE POPS FCST
IS THEREFORE LIMITED TO THE CHC RANGE FOR NOW.
FOG/LOW CLOUDS MAY BE POSSIBLE AGAIN TONIGHT AND IS SHOWN IN SOME
OF THE MOS GUIDANCE AS WELL AS THE 07.03Z SREF. ULTIMATE
DEVELOPMENT HOWEVER WILL DEPEND ON THE CONVECTIVE TRENDS
OVERNIGHT...SO CONFIDENCE WAS NOT HIGH ENOUGH TO INCLUDE IN THE
FCST AT THIS POINT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 356 AM CDT MON SEP 7 2015
CHILLY TUESDAY WITH LINGERING MORNING SHOWERS GIVING WAY TO
PARTLY SUNNY SKIES. COOL HIGH PRESSURE BUILDS ACROSS THE AREA AND
BATTLE BETWEEN CAA AND SEPTEMBER SUN. THE BIGGEST THING TO WATCH
IS HOW SOON CLOUDS DISSIPATE...WHICH WILL HAVE A DIRECT IMPACT ON
HIGHS. MOST AREAS HOLD IN THE 70S...EXCEPT FOR FAR SW WITH HIGHS
AROUND 80...ALTHOUGH AN EARLIER CLEARING WILL BUMP UP TEMPS A
GOOD 5 DEGREES OR MORE.
BL MOISTURE WILL BE A CONCERN TUESDAY NIGHT INTO WED MORN. THE
NAM WHICH HAS MORE BL MOISTURE SUGGESTS STRATUS/FOG COULD DEVELOP
WITH WINDS BECOMING SOUTHEASTERLY/SOUTHERLY ON THE BACK SIDE OF
THE SFC HIGH. THE GFS/EC MOS GUIDANCE IS DRIER AND KEEPS THINGS
CLEAR AND HAS SLIGHTLY LOWER TEMPS. MODELS HAVE BEEN STRUGGLING
WITH LOW LEVEL MOISTURE...WHICH LEADS TO LOW CONFIDENCE IN
WHETHER FOG/STRATUS WILL DEVELOP OR NOT.
WEDNESDAY WILL SEE THE NEXT WEAK COLD FRONT PUSH ACROSS THE AREA.
SLIGHT WARM UP AHEAD OF THE FRONT WITH MOST HIGHS AROUND 80 INTO
THE MID 80S. MODELS HAVE BEEN IN GOOD AGREEMENT DEVELOPING A LINE
OF STORMS ALONG THE BOUNDARY WHICH MODEL BLENDS PLACE ACROSS THE
HEART /FROM NORTHEAST TO SOUTHWEST/ OF THE CWA DURING PEAK
HEAT/INITIATION. SHEAR IS WEAK HOWEVER A NARROW BAND WITH CAPE
VALUES OF 500 TO 1000 J/KG SO EXPECT AT LEAST SOME ISOLD THUNDER.
HIGH PRESSURE BRINGS DRY AIR FOR THURSDAY. HIGH QUICKLY MOVES
EAST FOR FRIDAY WITH RETURN SOUTHERLY FLOW TO BRING AN INCREASE
OF MOISTURE. SOME AFTERNOON INSTABILITY DEVELOPS THEN A LL JET
KICKS IN OVERNIGHT. RESULTS IN AT LEAST A SLGHT CHANCE FOR
PRECIP FRIDAY INTO FRIDAY NIGHT. INBETWEEN SYSTEMS FOR THE
WEEKEND WITH SEASONAL AND DRY CONDITIONS EXPECTED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1248 PM CDT MON SEP 7 2015
VERY DIFFICULT AVIATION FORECAST OVER THE NEXT 24 HOURS FOR THE KLBF
AND KVTN TERMINALS. THE FIRST AREA OF CONCERN/DIFFICULTY IS THE
PERSISTENCE OF LOW CLOUDS OVER THE KLBF TERMINAL...WITH CURRENT
THINKING THAT MVFR CONDITIONS WILL CONTINUE THROUGH THE AFTERNOON
HOURS TODAY. THIS CURRENT THINKING IS SUPPORTED BY THE LATEST RUNS
OF THE RAP/NAM/AND HRRR MODELS...WHICH KEEP CEILINGS AT OR BELOW
3000FT THROUGH 02Z. THE NEXT AREA OF CONCERN/DIFFICULTY WILL BE THE
TIMING ON AFTERNOON/LATE EVENING CONVECTION WITHIN THE GENERAL
VICINITY OF THE KLBF AND KVTN TERMINALS. LATEST OPERATIONAL HRRR HAS
A LINE OF STORMS MOVING INTO THE SOUTHEASTERN PANHANDLE OF NEBRASKA
AND SOUTHWESTERN NEBRASKA BY 00Z THIS EVENING...AND THEN MOVING INTO
THE KLBF TERMINAL BETWEEN 02Z AND 05Z. A SECOND AREA OF CONVECTION
IS ALSO ANTICIPATED TO FORM OVER NORTHWESTERN NEBRASKA BETWEEN 21Z
AND 23Z...BEFORE MOVING EAST INTO THE KVTN TERMINAL BETWEEN 01Z AND
04Z. UNCERTAINTY DOES EXIST WITH SPATIAL COVERAGE OF THIS SECOND
AREA OF CONVECTION NEAR KVTN...HOWEVER...CURRENT CLEARING OVER
NORTHWESTERN NEBRASKA WOULD SUPPORT THE DEVELOPMENT OF THUNDERSTORMS
THIS AFTERNOON.
ANOTHER ROUND OF LOW CLOUDS ARE POSSIBLE TONIGHT AGAIN OVER THE KLBF
TERMINAL AFTER THE AREA OF SHOWERS/THUNDERSTORMS MOVES THROUGH
THIS EVENING. CONFIDENCE IS HIGH ENOUGH AT THIS TIME TO BRING
BACK IN MVFR CONDITIONS OVER THE KLBF TERMINAL...WITH EVEN THE
CHANCE FOR SOME DRIZZLE AFTER 09Z...HOWEVER...THIS WILL BE HIGHLY
DEPENDENT ON HOW MUCH MIXING (WHICH WOULD TEND TO SCOUR OUT THE
MOISTURE) OCCURS IN THE ATMOSPHERE ONCE THIS EVENINGS STORMS MOVE
THROUGH.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JWS
SHORT TERM...JWS
LONG TERM...MASEK
AVIATION...MOLDAN
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1236 PM CDT MON SEP 7 2015
.UPDATE...
ISSUED AT 1037 AM CDT MON SEP 7 2015
A COMPLEX SITUATION TODAY WITH POTENTIAL FOR TSTMS TO DEVELOP
OVER THE FCST AREA AS WELL AS MOVE IN FROM THE W.
PLEASE SEE THE 1252Z SPC DAY 1 OUTLOOK FOR AN EXCELLENT OVERVIEW
OF THE SITUATION.
YOU`VE PROBABLY SEEN THE UPGRADE TO A SLGT RISK. WE SAW THIS
POTENTIAL YESTERDAY AND BELIEVE IT IS WARRANTED.
ALL THE INGREDIENTS ARE THERE. OUR GREATEST CONCERN IS FROM HWY 6
DOWN INTO N-CNTRL KS IN VICINITY OF THE WARM FRONT. SHORT-TERM HI-
RES MODELS SUGGEST THE FRONT COULD LIFT BACK N INTO WEBSTER-
NUCKOLLS-THAYER COUNTIES. ANY STORMS THAT FORM ON OR NEAR THIS
FRONT WILL PROBABLY BE SUPERCELLS AND WILL NEED TO BE CLOSELY
MONITORED FOR ALL THREATS.
SKYWARN: BE ALERT FOR ACTIVATION IN THE 20Z-21Z TIME FRAME.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 AM CDT MON SEP 7 2015
MOSTLY CLEAR SKIES ARE BEING OBSERVED ACROSS THE LOCAL AREA THIS
MORNING...ALBEIT SOME LOW LEVEL STRATUS HAS BEGUN TO DEVELOP IN
SPOTS. WHILE THIS STRATUS IS PATCHY AT THE MOMENT...EXPECT THIS
STRATUS TO CONTINUE TO SPREAD IN COVERAGE THROUGH DAY BREAK...WITH
SOME LOCALLY DENSE FOG ALSO POSSIBLE THROUGH THE EARLY MORNING
HOURS. THUS FAR...FOG HAS NOT BEEN ABLE TO DEVELOP...BUT WITH DEW
POINT DEPRESSIONS CONTINUING TO SHRINK AND A FEW TEMPS NOW
REACHING THEIR ASSOCIATED DEWPOINT VALUES...CONTINUE TO THINK THE
LATEST HRRR MIGHT BE CORRECT WITH AT LEAST SOME PATCHY DENSE FOG
DEVELOPING AROUND SUNRISE. AS A RESULT...CONTINUED TO MAINTAIN THE
LOWER VISIBILITY WORDING FOR THE MORNING HOURS OF THE FORECAST AND
WILL ALSO CONTINUE TO ADVERTISE IN THE HWO.
WITH SOME CONVECTION ALREADY FORMING ACROSS THE HIGH PLAINS...AND
FAVORABLE UPPER LEVEL JET DYNAMICS EXPECT BY MID AFTERNOON...
EXPECT SOME SHOWERS AND THUNDERSTORMS TO DEVELOP AND MOVE ACROSS
THE REGION...GENERALLY FAVORING AREAS ACROSS SOUTH CENTRAL
NEBRASKA. MODEL SOUNDINGS ARE INDICATIVE OF AMPLE CAPE ACROSS THE
REGION...AND THIS INSTABILITY COMBINED WITH 0-6KM SHEAR VALUES
UPWARDS OF 50KTS EXPECTED LATER IN THE DAY...WOULD NOT BE
SURPRISED TO SEE A FEW STRONG AND ORGANIZED THUNDERSTORMS DEVELOP
ACROSS THE LOCAL AREA. LATEST CONVECTIVE OUTLOOK FROM SPC IS
INDICATIVE OF THIS...WITH THE ENTIRE AREA RIGHT IN THE MIDDLE OF A
MARGINAL RISK FOR SEVERE WEATHER THIS AFTERNOON. AS WITH YESTERDAY
...WHILE THE OVERALL TORNADO THREAT IS FAIRLY LOW...A 2 PERCENT
TORNADO RISK IS IN THE LATEST OUTLOOK...AND WILL ADD THIS MENTION
TO THE HWO DESPITE LARGE HAIL AND THUNDERSTORM WIND GUSTS BEING
THE PRIMARY CONCERNS.
TEMPERATURE WISE...EXPECT MOST AREAS TO STRUGGLE TO REACH OR
SLIGHTLY EXCEED 80 DEGREES THIS AFTERNOON...WHICH WILL BE A NICE
CHANCE FOR MOST FOLKS. ONCE SKIES CLEAR AND RAINFALL CHANCES
DIMINISH SOME OVERNIGHT...EXPECT A SEASONABLY COOL START TO
TUESDAY FOR THE LOCAL AREA...WITH NEAR TO SLIGHTLY ABOVE SEASONAL
NORMS FOR LOW TEMPERATURES...WITH FORECAST LOWS GENERALLY FALLING
INTO THE UPPER 50S ACROSS OUR NORTH...AND INTO THE LOWER TO MIDDLE
60S ACROSS NORTH CENTRAL KANSAS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 405 AM CDT MON SEP 7 2015
PRIMARY FORECAST CONCERN THROUGH THE LONG TERM LIES WITH
PRECIPITATION CHANCES.
THE START OF THE PERIOD SHOWS MODELS NOT IN TOO BAD OF AGREEMENT
WITH THE OVERALL UPPER LEVEL PATTERN...WITH THE CWA UNDER ZONAL TO
SLIGHTLY SWRLY FLOW...THANKS TO BROAD TROUGHING CONNECTED TO A LOW
PRESSURE SYSTEM LOCATED OVER NORTH CENTRAL CANADA. AT THE SFC...
STILL EXPECTING THERE TO BE A FRONTAL BOUNDARY MEANDERING AROUND
THE AREA...THOUGH EXACT PLACEMENT IS UNCERTAIN AS IT WILL LIKELY
BE AFFECTED BY ANY THUNDERSTORMS MOVING THROUGH TONIGHT. CONTINUE
TO HAVE POPS RIGHT OFF THE BAT TUESDAY MORNING...LINGERING
ACTIVITY FROM TONIGHT...WHICH IS EXPECTED TO BE SLIDING OFF TO THE
EAST WITH A GRADUALLY VEERING/WANING LLJ. THINKING IS THAT THERE
WILL BE AT LEAST A BIT OF A BREAK IN ACTIVITY LATER IN THE MORNING
PERHAPS INTO THE EARLY AFTERNOON HOURS...BUT ANOTHER LOBE OF
SHORTWAVE ENERGY ASSOCIATED WITH THAT UPPER LEVEL CANADIAN LOW IS
EXPECTED TO MOVE INTO THE AREA FROM THE NW LATE IN THE
AFTERNOON...PROVIDING THE OPPORTUNITY FOR ADDITIONAL
THUNDERSTORMS. WHILE KEPT POPS IN PLACE CWA-WIDE DURING THE
AFTERNOON...HAVE 30-40 POPS GOING ACROSS THE SERN PORTIONS OF THE
CWA...CLOSER TO THE MAIN SFC FRONT WHICH LOOKS TO EXTEND FROM EAST
CENTRAL TO SOUTH CENTRAL PORTIONS OF KS BY TUES EVENING. HAVE SOME
LINGERING 20 POPS DURING THE EVENING HOURS...BUT KEPT THE FORECAST
DRY POST-06Z AS THINGS GET PUSHED FURTHER S/SE. CONFIDENCE IN
TEMPS FOR TUESDAY IS NOT HIGH...AND WILL BE GREATLY AFFECTED BY
LINGERING PRECIP/CLOUDS AS WELL AS THE ULTIMATE LOCATION OF THE
SFC BOUNDARY. AT THIS POINT...HIGHS ARE FORECAST TO REACH THE
UPPER 70S TO LOWER 80S.
THE FORECAST FOR WED IS A DRY ONE...WITH THE TUES SYSTEM EXPECTED
TO PUSH OFF TO THE EAST...LEAVING MORE NWRLY /BUT STILL LOW
AMPLITUDE/ UPPER LEVEL FLOW IN ITS WAKE. A WEAK SFC PATTERN AND
LIGHT WINDS TO START THE DAY IS EXPECTED TO GIVE WAY TO MORE
SOUTHERLY WINDS WITH TIME...AS SFC LOW PRESSURE BECOMES BETTER
ORGANIZED TO OUR WEST AHEAD OF THE NEXT UPPER LEVEL SYSTEM
APPROACHING THE REGION FROM THE NW. THE LACK OF A NOTABLE CHANGE
IN AIR MASS BEHIND THE EARLY WEEK FRONT LOOKS TO KEEP HIGH TEMPS
FOR WED IN THE UPPER 70S/LOWER 80S.
LOOKING AT THE WED NIGHT THROUGH EARLY SAT PERIOD...CONFIDENCE IN
THE FORECAST IS NOT HIGH...AS PLENTY OF DIFFERENCES BETWEEN MODELS
REMAIN. THE LATEST RUN OF THE GFS SHOWS THE POSSIBILITY OF A
COUPLE OF SHORTWAVE DISTURBANCES MOVING THROUGH DURING THIS TIME
FRAME...WHILE THE ECMWF SHOWS A MORE ORGANIZED CLOSED LOW
DEVELOPING BY THURS EVENING OVER THE WRN GREAT LAKES AND PUSHING
OFF TO THE EAST. ONE OF THE RESULTING DIFFERENCES IS THE GFS WOULD
BRING A COUPLE OF SHOTS AT PRECIP...VS THE LIKELY JUST ONE SHOT
VIA THE ECMWF. HAD INHERITED A FEW PERIODS OF POPS IN THIS TIME
FRAME...AND WITH THE GFS STILL SUPPORTING THAT WILL KEEP IT
GOING...BUT IF THINGS TREND TOWARD THE 00Z ECMWF...SOME OF THOSE
PERIOD WOULD NEED TO HAVE POPS REMOVED. WE SHALL SEE. BOTH
SOLUTIONS SHOW ANOTHER SFC COLD FRONT MOVING THROUGH THE
REGION...WITH THE ECMWF SHOWING A BETTER PUSH OF COOLER AIR THAN
THE GFS AT THIS POINT. FORECAST HIGHS REMAIN A BLEND THURS-
SAT...DROPPING BACK INTO THE 70S CWA-WIDE.
BETTER AGREEMENT KEEPING SUN DRY...WITH HIGHS REBOUNDING BACK
INTO THE 80S FOR MAINLY THE SWRN THIRD OR SO OF THE CWA.
&&
.AVIATION...(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z TUE AFTERNOON)
ISSUED AT 1236 PM CDT MON SEP 7 2015
SIGNIFICANT WX ISSUES: +TSRA POTENTIAL MAINLY 22Z-03Z THEN LIFR OR
VLIFR STRATUS AND FOG POSSIBLE AGAIN 09Z-15Z TOMORROW.
THIS AFTERNOON: A BAND OF SHWRS WITH EMBEDDED THUNDER HAS EXITED
EAR AND WILL MOVE THRU GRI BEFORE 19Z. LIFR CIGS SHOULD EVENTUALLY
LIFT TO IFR AND EVENTUALLY MVFR. TIMING IS HIGHLY UNCERTAIN. SCT
TSTMS WILL ERUPT AFTER 21Z AND THERE IS POTENTIAL FOR 1" HAIL OR
LARGER AND G50 KTS IF EITHER TERMINAL TAKES A DIRECT HIT. LIGHT
E-NE WINDS UNDER 10 KTS AWAY FROM ANY TSTMS. CONFIDENCE: MEDIUM
TONIGHT: TSTMS END WITH A PERIOD OF MULTI-LAYERED VFR CIGS BEFORE
IFR STRATUS AND POSSIBLY FOG REDEVELOPS AFTER 06Z. LIGHT NE WINDS
UNDER 10 KTS. CONFIDENCE: MEDIUM
TUE THRU 18Z: PROBABLY IFR TO START IN FOG/STRATUS WITH GRADUAL
IMPROVEMENT TO MVFR BY 18Z. CONFIDENCE: MEDIUM
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...ROSSI
LONG TERM...ADP
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1037 AM CDT MON SEP 7 2015
...MUCH OF THE FCST AREA UPGRADED TO A SLGT RISK OF SVR WX
TODAY...
.UPDATE...
ISSUED AT 1037 AM CDT MON SEP 7 2015
A COMPLEX SITUATION TODAY WITH POTENTIAL FOR TSTMS TO DEVELOP
OVER THE FCST AREA AS WELL AS MOVE IN FROM THE W.
PLEASE SEE THE 1252Z SPC DAY 1 OUTLOOK FOR AN EXCELLENT OVERVIEW
OF THE SITUATION.
YOU`VE PROBABLY SEEN THE UPGRADE TO A SLGT RISK. WE SAW THIS
POTENTIAL YESTERDAY AND BELIEVE IT IS WARRANTED.
ALL THE INGREDIENTS ARE THERE. OUR GREATEST CONCERN IS FROM HWY 6
DOWN INTO N-CNTRL KS IN VICINITY OF THE WARM FRONT. SHORT-TERM HI-
RES MODELS SUGGEST THE FRONT COULD LIFT BACK N INTO WEBSTER-
NUCKOLLS-THAYER COUNTIES. ANY STORMS THAT FORM ON OR NEAR THIS
FRONT WILL PROBABLY BE SUPERCELLS AND WILL NEED TO BE CLOSELY
MONITORED FOR ALL THREATS.
SKYWARN: BE ALERT FOR ACTIVATION IN THE 20Z-21Z TIME FRAME.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 AM CDT MON SEP 7 2015
MOSTLY CLEAR SKIES ARE BEING OBSERVED ACROSS THE LOCAL AREA THIS
MORNING...ALBEIT SOME LOW LEVEL STRATUS HAS BEGUN TO DEVELOP IN
SPOTS. WHILE THIS STRATUS IS PATCHY AT THE MOMENT...EXPECT THIS
STRATUS TO CONTINUE TO SPREAD IN COVERAGE THROUGH DAY BREAK...WITH
SOME LOCALLY DENSE FOG ALSO POSSIBLE THROUGH THE EARLY MORNING
HOURS. THUS FAR...FOG HAS NOT BEEN ABLE TO DEVELOP...BUT WITH DEW
POINT DEPRESSIONS CONTINUING TO SHRINK AND A FEW TEMPS NOW
REACHING THEIR ASSOCIATED DEWPOINT VALUES...CONTINUE TO THINK THE
LATEST HRRR MIGHT BE CORRECT WITH AT LEAST SOME PATCHY DENSE FOG
DEVELOPING AROUND SUNRISE. AS A RESULT...CONTINUED TO MAINTAIN THE
LOWER VISIBILITY WORDING FOR THE MORNING HOURS OF THE FORECAST AND
WILL ALSO CONTINUE TO ADVERTISE IN THE HWO.
WITH SOME CONVECTION ALREADY FORMING ACROSS THE HIGH PLAINS...AND
FAVORABLE UPPER LEVEL JET DYNAMICS EXPECT BY MID AFTERNOON...
EXPECT SOME SHOWERS AND THUNDERSTORMS TO DEVELOP AND MOVE ACROSS
THE REGION...GENERALLY FAVORING AREAS ACROSS SOUTH CENTRAL
NEBRASKA. MODEL SOUNDINGS ARE INDICATIVE OF AMPLE CAPE ACROSS THE
REGION...AND THIS INSTABILITY COMBINED WITH 0-6KM SHEAR VALUES
UPWARDS OF 50KTS EXPECTED LATER IN THE DAY...WOULD NOT BE
SURPRISED TO SEE A FEW STRONG AND ORGANIZED THUNDERSTORMS DEVELOP
ACROSS THE LOCAL AREA. LATEST CONVECTIVE OUTLOOK FROM SPC IS
INDICATIVE OF THIS...WITH THE ENTIRE AREA RIGHT IN THE MIDDLE OF A
MARGINAL RISK FOR SEVERE WEATHER THIS AFTERNOON. AS WITH YESTERDAY
...WHILE THE OVERALL TORNADO THREAT IS FAIRLY LOW...A 2 PERCENT
TORNADO RISK IS IN THE LATEST OUTLOOK...AND WILL ADD THIS MENTION
TO THE HWO DESPITE LARGE HAIL AND THUNDERSTORM WIND GUSTS BEING
THE PRIMARY CONCERNS.
TEMPERATURE WISE...EXPECT MOST AREAS TO STRUGGLE TO REACH OR
SLIGHTLY EXCEED 80 DEGREES THIS AFTERNOON...WHICH WILL BE A NICE
CHANCE FOR MOST FOLKS. ONCE SKIES CLEAR AND RAINFALL CHANCES
DIMINISH SOME OVERNIGHT...EXPECT A SEASONABLY COOL START TO
TUESDAY FOR THE LOCAL AREA...WITH NEAR TO SLIGHTLY ABOVE SEASONAL
NORMS FOR LOW TEMPERATURES...WITH FORECAST LOWS GENERALLY FALLING
INTO THE UPPER 50S ACROSS OUR NORTH...AND INTO THE LOWER TO MIDDLE
60S ACROSS NORTH CENTRAL KANSAS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 405 AM CDT MON SEP 7 2015
PRIMARY FORECAST CONCERN THROUGH THE LONG TERM LIES WITH
PRECIPITATION CHANCES.
THE START OF THE PERIOD SHOWS MODELS NOT IN TOO BAD OF AGREEMENT
WITH THE OVERALL UPPER LEVEL PATTERN...WITH THE CWA UNDER ZONAL TO
SLIGHTLY SWRLY FLOW...THANKS TO BROAD TROUGHING CONNECTED TO A LOW
PRESSURE SYSTEM LOCATED OVER NORTH CENTRAL CANADA. AT THE SFC...
STILL EXPECTING THERE TO BE A FRONTAL BOUNDARY MEANDERING AROUND
THE AREA...THOUGH EXACT PLACEMENT IS UNCERTAIN AS IT WILL LIKELY
BE AFFECTED BY ANY THUNDERSTORMS MOVING THROUGH TONIGHT. CONTINUE
TO HAVE POPS RIGHT OFF THE BAT TUESDAY MORNING...LINGERING
ACTIVITY FROM TONIGHT...WHICH IS EXPECTED TO BE SLIDING OFF TO THE
EAST WITH A GRADUALLY VEERING/WANING LLJ. THINKING IS THAT THERE
WILL BE AT LEAST A BIT OF A BREAK IN ACTIVITY LATER IN THE MORNING
PERHAPS INTO THE EARLY AFTERNOON HOURS...BUT ANOTHER LOBE OF
SHORTWAVE ENERGY ASSOCIATED WITH THAT UPPER LEVEL CANADIAN LOW IS
EXPECTED TO MOVE INTO THE AREA FROM THE NW LATE IN THE
AFTERNOON...PROVIDING THE OPPORTUNITY FOR ADDITIONAL
THUNDERSTORMS. WHILE KEPT POPS IN PLACE CWA-WIDE DURING THE
AFTERNOON...HAVE 30-40 POPS GOING ACROSS THE SERN PORTIONS OF THE
CWA...CLOSER TO THE MAIN SFC FRONT WHICH LOOKS TO EXTEND FROM EAST
CENTRAL TO SOUTH CENTRAL PORTIONS OF KS BY TUES EVENING. HAVE SOME
LINGERING 20 POPS DURING THE EVENING HOURS...BUT KEPT THE FORECAST
DRY POST-06Z AS THINGS GET PUSHED FURTHER S/SE. CONFIDENCE IN
TEMPS FOR TUESDAY IS NOT HIGH...AND WILL BE GREATLY AFFECTED BY
LINGERING PRECIP/CLOUDS AS WELL AS THE ULTIMATE LOCATION OF THE
SFC BOUNDARY. AT THIS POINT...HIGHS ARE FORECAST TO REACH THE
UPPER 70S TO LOWER 80S.
THE FORECAST FOR WED IS A DRY ONE...WITH THE TUES SYSTEM EXPECTED
TO PUSH OFF TO THE EAST...LEAVING MORE NWRLY /BUT STILL LOW
AMPLITUDE/ UPPER LEVEL FLOW IN ITS WAKE. A WEAK SFC PATTERN AND
LIGHT WINDS TO START THE DAY IS EXPECTED TO GIVE WAY TO MORE
SOUTHERLY WINDS WITH TIME...AS SFC LOW PRESSURE BECOMES BETTER
ORGANIZED TO OUR WEST AHEAD OF THE NEXT UPPER LEVEL SYSTEM
APPROACHING THE REGION FROM THE NW. THE LACK OF A NOTABLE CHANGE
IN AIR MASS BEHIND THE EARLY WEEK FRONT LOOKS TO KEEP HIGH TEMPS
FOR WED IN THE UPPER 70S/LOWER 80S.
LOOKING AT THE WED NIGHT THROUGH EARLY SAT PERIOD...CONFIDENCE IN
THE FORECAST IS NOT HIGH...AS PLENTY OF DIFFERENCES BETWEEN MODELS
REMAIN. THE LATEST RUN OF THE GFS SHOWS THE POSSIBILITY OF A
COUPLE OF SHORTWAVE DISTURBANCES MOVING THROUGH DURING THIS TIME
FRAME...WHILE THE ECMWF SHOWS A MORE ORGANIZED CLOSED LOW
DEVELOPING BY THURS EVENING OVER THE WRN GREAT LAKES AND PUSHING
OFF TO THE EAST. ONE OF THE RESULTING DIFFERENCES IS THE GFS WOULD
BRING A COUPLE OF SHOTS AT PRECIP...VS THE LIKELY JUST ONE SHOT
VIA THE ECMWF. HAD INHERITED A FEW PERIODS OF POPS IN THIS TIME
FRAME...AND WITH THE GFS STILL SUPPORTING THAT WILL KEEP IT
GOING...BUT IF THINGS TREND TOWARD THE 00Z ECMWF...SOME OF THOSE
PERIOD WOULD NEED TO HAVE POPS REMOVED. WE SHALL SEE. BOTH
SOLUTIONS SHOW ANOTHER SFC COLD FRONT MOVING THROUGH THE
REGION...WITH THE ECMWF SHOWING A BETTER PUSH OF COOLER AIR THAN
THE GFS AT THIS POINT. FORECAST HIGHS REMAIN A BLEND THURS-
SAT...DROPPING BACK INTO THE 70S CWA-WIDE.
BETTER AGREEMENT KEEPING SUN DRY...WITH HIGHS REBOUNDING BACK
INTO THE 80S FOR MAINLY THE SWRN THIRD OR SO OF THE CWA.
&&
.AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z TUE MORNING)
ISSUED AT 550 AM CDT MON SEP 7 2015
LOW LEVEL STRATUS HAS MOVED IN ACROSS THE AREA WITH IFR CIGS NOW
BEING OBSERVED AT BOTH TERMINALS. WITH THIS LOW STRATUS...MAY NOT
SEE VSBYS DROP AS LOW AS PREVIOUSLY THOUGH...BUT WITH A FEW SITES
SHOWING IFR VSBYS...OPTED TO INCLUDE THE MENTION OF BR FOR SEVERAL
HOURS THIS MORNING. OTHERWISE...EXPECT THE STRATUS TO BE SLOW TO
BURN OFF BY LATE MORNING...WITH INCREASING CHANCES FOR
THUNDERSTORMS THEREAFTER. OUTSIDE OF ANY THUNDERSTORM ACTIVITY...
WINDS ARE EXPECTED TO REMAIN FAIRLY LIGHT TODAY...GENERALLY OUT
OF THE EAST OR NORTHEAST AT 10 MPH OR LESS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...ROSSI
LONG TERM...ADP
AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
642 AM CDT MON SEP 7 2015
.SYNOPSIS...
ISSUED AT 356 AM CDT MON SEP 7 2015
LARGE UPPER LOW LOCATED OVER SRN CANADA WITH TROUGH AXIS SWD INTO
MT AND ID...WITH NOTABLE PV ANOMALY MOVING THROUGH THE BASE OF
THE TROUGH OVER NRN NV. ZONE OF HIGHER SWRLY FLOW ALOFT LOCATED
AHEAD OF THIS UPPER TROUGH FROM MN TO SRN CA...RUNNING THROUGH
THE NWRN CORNER OF NEB. ALONG THIS SWRLY FLOW ALOFT...WEAK SHORT
WAVES CONTINUE TO PROGRESS QUICKLY NEWD AS THEY HAVE THE PAST FEW
DAYS. SFC FRONT THAT MOVED THROUGH THE AREA THIS MORNING LOCATED
FROM SRN IA ACROSS NERN KS SWWD TO NEAR DDC. THIS FRONT MARKED BY
CONVECTION FROM SRN IA INTO NERN KS. ON THE NORTH SIDE OF THIS
FRONT...ERLY UPSLOPE FLOW EXISTS AT THE SFC WITH NERLY WIND AT
500M/1KM AT KLNX. SFC WINDS HAVE TURNED SERLY ALREADY FROM THE
PANHANDLE INTO NWRN KS AND THIS IS CONTRIBUTING TO TSRA
DEVELOPMENT ACROSS WRN NEB. VSBYS STARTING TO BE REDUCED IN THE
ONL AREA DUE TO FOG.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 356 AM CDT MON SEP 7 2015
FOR THIS MORNING...TSRA DEVELOPING AND MOVING EWD ALONG GRADIENT
OF STEEPER LAPSE RATES ALOFT AND WILL LIKELY BE SUSTAINED AS
ELEVATED INSTABILITY EXPANDS EWD IN INCREASING ISENTROPIC
UPGLIDE. CIRA LOW CLOUD/FOG PRODUCT SHOWING ONLY LIMITED
DEVELOPMENT OF LOW CLOUDS AS EXPECTED BY SHORT RANGE MODELS AND
SREF PROBABILITY GUIDANCE. WILL CONTINUE THE IDEA OF PATCHY FOG
THOUGH CONVECTIVE TRENDS SO FAR WOULD SUGGEST FURTHER FOG
DEVELOPMENT MAY BE INHIBITED SOMEWHAT.
PREVIOUSLY MENTIONED PV ANOMALY OVER NRN NV WILL CONTINUE TO
ROTATE NEWD TODAY AND AS THE ENTIRE TROUGH PULLS EWD...UPPER
LEVEL JET DEVELOPMENT OCCURS IN CONFLUENT ZONE OVER WY TODAY.
THIS WILL PUT THE RIGHT ENTRANCE REGION OF THE NEWLY DEVELOP JET
STREAK OVER WRN NEB BY AFTERNOON. THE RESULTING DIRECT THERMAL
CIRCULATION THAT IS ALREADY DEVELOPING IN RESPONSE OVER THE HIGH
PLAINS...AS EVIDENCED BY ISENTROPIC LIFT ON THE 310/315K
SFC...WILL INDUCE A NWRLY LOW LEVEL AGEOSTROPHIC FLOW AND ENHANCE
FRONTOGENSIS ACROSS THE WRN PORTION OF THE AREA THIS AFTERNOON.
AS THIS OCCURS IN A REGION OF DECENT MID LEVEL INSTABILITY...NEW
TSRA SHOULD DEVELOP THIS AFTERNOON IN WRN NEB AND MOVE EWD. CAPE
IS NOT EXTREME BUT WITH GOOD SHEAR IN PLACE THROUGH A DEEP LAYER
SOME POTENTIAL FOR LARGE HAIL WILL EXIST WITH ANY STORMS THAT DO
DEVELOP...HENCE THE MARGINAL RISK AS DEPICTED BY SPC. THE FLY IN
THE OINTMENT HERE WOULD BE ONGOING CONVECTION AND CONVECTIVE
DEBRIS THAT REMAIN FROM THIS MORNINGS CONVECTION AND HOW THAT
AFFECTS THE ATMOSPHERE BY THIS AFTERNOON. CLOUD COVER MAY
NEGATIVELY AFFECT THE STORMS BEING ABLE TO REALIZE AVAILABLE
CAPE...BUT LEFT OVER BOUNDARIES MAY BE A FOCUS FOR UPWARD
VERTICAL MOTION ENHANCEMENT TO POSITIVELY INFLUENCE INDIVIDUAL
UPDRAFTS...SO ANOTHER COMPLICATED FCST REMAINS. SHORT RANGE
MODELS AND CAM ENSEMBLES AGAIN SUGGEST A WIDE RANGE OF POSSIBLE
SOLUTIONS. ALTHOUGH THE HRRR HAS HAD ITS STRUGGLES LATELY...THINK
IT MIGHT BE ON TO THE RIGHT IDEA DEVELOPING TSRA IN THE 3-4PM CDT
TIME RANGE. THIS IDEA IS ALSO SUPPORTED BY THE NSSL WRF AND BY A
FEW MEMBERS OF THE NCAR 10 MEMBER 3KM WRF ENSEMBLE. THE POPS FCST
IS THEREFORE LIMITED TO THE CHC RANGE FOR NOW.
FOG/LOW CLOUDS MAY BE POSSIBLE AGAIN TONIGHT AND IS SHOWN IN SOME
OF THE MOS GUIDANCE AS WELL AS THE 07.03Z SREF. ULTIMATE
DEVELOPMENT HOWEVER WILL DEPEND ON THE CONVECTIVE TRENDS
OVERNIGHT...SO CONFIDENCE WAS NOT HIGH ENOUGH TO INCLUDE IN THE
FCST AT THIS POINT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 356 AM CDT MON SEP 7 2015
CHILLY TUESDAY WITH LINGERING MORNING SHOWERS GIVING WAY TO
PARTLY SUNNY SKIES. COOL HIGH PRESSURE BUILDS ACROSS THE AREA AND
BATTLE BETWEEN CAA AND SEPTEMBER SUN. THE BIGGEST THING TO WATCH
IS HOW SOON CLOUDS DISSIPATE...WHICH WILL HAVE A DIRECT IMPACT ON
HIGHS. MOST AREAS HOLD IN THE 70S...EXCEPT FOR FAR SW WITH HIGHS
AROUND 80...ALTHOUGH AN EARLIER CLEARING WILL BUMP UP TEMPS A
GOOD 5 DEGREES OR MORE.
BL MOISTURE WILL BE A CONCERN TUESDAY NIGHT INTO WED MORN. THE
NAM WHICH HAS MORE BL MOISTURE SUGGESTS STRATUS/FOG COULD DEVELOP
WITH WINDS BECOMING SOUTHEASTERLY/SOUTHERLY ON THE BACK SIDE OF
THE SFC HIGH. THE GFS/EC MOS GUIDANCE IS DRIER AND KEEPS THINGS
CLEAR AND HAS SLIGHTLY LOWER TEMPS. MODELS HAVE BEEN STRUGGLING
WITH LOW LEVEL MOISTURE...WHICH LEADS TO LOW CONFIDENCE IN
WHETHER FOG/STRATUS WILL DEVELOP OR NOT.
WEDNESDAY WILL SEE THE NEXT WEAK COLD FRONT PUSH ACROSS THE AREA.
SLIGHT WARM UP AHEAD OF THE FRONT WITH MOST HIGHS AROUND 80 INTO
THE MID 80S. MODELS HAVE BEEN IN GOOD AGREEMENT DEVELOPING A LINE
OF STORMS ALONG THE BOUNDARY WHICH MODEL BLENDS PLACE ACROSS THE
HEART /FROM NORTHEAST TO SOUTHWEST/ OF THE CWA DURING PEAK
HEAT/INITIATION. SHEAR IS WEAK HOWEVER A NARROW BAND WITH CAPE
VALUES OF 500 TO 1000 J/KG SO EXPECT AT LEAST SOME ISOLD THUNDER.
HIGH PRESSURE BRINGS DRY AIR FOR THURSDAY. HIGH QUICKLY MOVES
EAST FOR FRIDAY WITH RETURN SOUTHERLY FLOW TO BRING AN INCREASE
OF MOISTURE. SOME AFTERNOON INSTABILITY DEVELOPS THEN A LL JET
KICKS IN OVERNIGHT. RESULTS IN AT LEAST A SLGHT CHANCE FOR
PRECIP FRIDAY INTO FRIDAY NIGHT. INBETWEEN SYSTEMS FOR THE
WEEKEND WITH SEASONAL AND DRY CONDITIONS EXPECTED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 642 AM CDT MON SEP 7 2015
VERY DIFFICULT AVIATION FCST FOR THE NEXT 24 HRS. CIRA LOW
CLOUD/VIS PRODUCT SHOWING THE LOWER CLOUDS ACROSS PORTIONS OF
CENTRAL INTO SW NEB...AND OBS/AREA WEB CAMS SHOWING REDUCTIONS IN
VSBY AROUND O`NEILL SWWD TO NEAR BBW. CIGS ARE IFR IN THE ERN
AREAS AS WELL WITH MVFR IN THE SW. AC AND SCT SHRA MOVING NEWD
ATOP THESE LOWER CLOUDS IN AN AREA OF ELEVATED INSTABILITY.
OPERATIONAL HRRR SUGGESTING THESE WILL MOVE OUT BUT NEW
DEVELOPMENT NEAR KLBF BY LATE MORNING WOULD OCCUR...AND THIS
BACKED UP WITH RAP AND A FEW WRF VERSIONS. HAVE THEREFORE INCLUDED
SEVERAL ROUNDS OF PRECIP IN OR NEAR THE KLBF TAF SITE TODAY. FCST
SOUNDINGS SHOW LOW CLOUDS AND LOW VSBYS /IFR CONDITIONS/ WOULD
STAY EAST OF KVTN TODAY...BUT OVERALL CONFIDENCE IN THIS FCST IS
LOW. TIMING OF SUBSEQUENT TSRA WITH FRONT THIS AFTERNOON AND
EVENING IS DEPENDANT ON SEVERAL FACTORS INCLUDING HOW MUCH
SUNSHINE WILL OCCUR POST MORNING CONVECTION.
AFTER NEXT FRONT MOVES THROUGH TONIGHT AND ESSENTIALLY WASHES OUT
COULD SEE ANOTHER ROUND OF LOW CLOUDS TONIGHT...BUT AGAIN
CONFIDENCE IN THIS SOLUTIONS IS LOW AT THIS POINT AND HAVE
THEREFORE NOT INCLUDED IT.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JWS
SHORT TERM...JWS
LONG TERM...MASEK
AVIATION...JWS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
622 AM CDT MON SEP 7 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 AM CDT MON SEP 7 2015
MOSTLY CLEAR SKIES ARE BEING OBSERVED ACROSS THE LOCAL AREA THIS
MORNING...ALBEIT SOME LOW LEVEL STRATUS HAS BEGUN TO DEVELOP IN
SPOTS. WHILE THIS STRATUS IS PATCHY AT THE MOMENT...EXPECT THIS
STRATUS TO CONTINUE TO SPREAD IN COVERAGE THROUGH DAY BREAK...WITH
SOME LOCALLY DENSE FOG ALSO POSSIBLE THROUGH THE EARLY MORNING
HOURS. THUS FAR...FOG HAS NOT BEEN ABLE TO DEVELOP...BUT WITH DEW
POINT DEPRESSIONS CONTINUING TO SHRINK AND A FEW TEMPS NOW
REACHING THEIR ASSOCIATED DEWPOINT VALUES...CONTINUE TO THINK THE
LATEST HRRR MIGHT BE CORRECT WITH AT LEAST SOME PATCHY DENSE FOG
DEVELOPING AROUND SUNRISE. AS A RESULT...CONTINUED TO MAINTAIN THE
LOWER VISIBILITY WORDING FOR THE MORNING HOURS OF THE FORECAST
AND WILL ALSO CONTINUE TO ADVERTISE IN THE HWO.
WITH SOME CONVECTION ALREADY FORMING ACROSS THE HIGH PLAINS...AND
FAVORABLE UPPER LEVEL JET DYNAMICS EXPECT BY MID
AFTERNOON...EXPECT SOME SHOWERS AND THUNDERSTORMS TO DEVELOP AND
MOVE ACROSS THE REGION...GENERALLY FAVORING AREAS ACROSS SOUTH
CENTRAL NEBRASKA. MODEL SOUNDINGS ARE INDICATIVE OF AMPLE CAPE
ACROSS THE REGION...AND THIS INSTABILITY COMBINED WITH 0-6KM SHEAR
VALUES UPWARDS OF 50KTS EXPECTED LATER IN THE DAY...WOULD NOT BE
SURPRISED TO SEE A FEW STRONG AND ORGANIZED THUNDERSTORMS DEVELOP
ACROSS THE LOCAL AREA. LATEST CONVECTIVE OUTLOOK FROM SPC IS
INDICATIVE OF THIS...WITH THE ENTIRE AREA RIGHT IN THE MIDDLE OF A
MARGINAL RISK FOR SEVERE WEATHER THIS AFTERNOON. AS WITH
YESTERDAY...WHILE THE OVERALL TORNADO THREAT IS FAIRLY LOW...A 2
PERCENT TORNADO RISK IS IN THE LATEST OUTLOOK...AND WILL ADD THIS
MENTION TO THE HWO DESPITE LARGE HAIL AND THUNDERSTORM WIND GUSTS
BEING THE PRIMARY CONCERNS.
TEMPERATURE WISE...EXPECT MOST AREAS TO STRUGGLE TO REACH OR
SLIGHTLY EXCEED 80 DEGREES THIS AFTERNOON...WHICH WILL BE A NICE
CHANCE FOR MOST FOLKS. ONCE SKIES CLEAR AND RAINFALL CHANCES
DIMINISH SOME OVERNIGHT...EXPECT A SEASONABLY COOL START TO
TUESDAY FOR THE LOCAL AREA...WITH NEAR TO SLIGHTLY ABOVE SEASONAL
NORMS FOR LOW TEMPERATURES...WITH FORECAST LOWS GENERALLY FALLING
INTO THE UPPER 50S ACROSS OUR NORTH...AND INTO THE LOWER TO MIDDLE
60S ACROSS NORTH CENTRAL KANSAS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 405 AM CDT MON SEP 7 2015
PRIMARY FORECAST CONCERN THROUGH THE LONG TERM LIES WITH
PRECIPITATION CHANCES.
THE START OF THE PERIOD SHOWS MODELS NOT IN TOO BAD OF AGREEMENT
WITH THE OVERALL UPPER LEVEL PATTERN...WITH THE CWA UNDER ZONAL TO
SLIGHTLY SWRLY FLOW...THANKS TO BROAD TROUGHING CONNECTED TO A LOW
PRESSURE SYSTEM LOCATED OVER NORTH CENTRAL CANADA. AT THE
SFC...STILL EXPECTING THERE TO BE A FRONTAL BOUNDARY MEANDERING
AROUND THE AREA...THOUGH EXACT PLACEMENT IS UNCERTAIN AS IT WILL
LIKELY BE AFFECTED BY ANY THUNDERSTORMS MOVING THROUGH TONIGHT.
CONTINUE TO HAVE POPS RIGHT OFF THE BAT TUESDAY MORNING...LINGERING
ACTIVITY FROM TONIGHT...WHICH IS EXPECTED TO BE SLIDING OFF TO THE
EAST WITH A GRADUALLY VEERING/WANING LLJ. THINKING IS THAT THERE
WILL BE AT LEAST A BIT OF A BREAK IN ACTIVITY LATER IN THE MORNING
PERHAPS INTO THE EARLY AFTERNOON HOURS...BUT ANOTHER LOBE OF
SHORTWAVE ENERGY ASSOCIATED WITH THAT UPPER LEVEL CANADIAN LOW IS
EXPECTED TO MOVE INTO THE AREA FROM THE NW LATE IN THE
AFTERNOON...PROVIDING THE OPPORTUNITY FOR ADDITIONAL THUNDERSTORMS.
WHILE KEPT POPS IN PLACE CWA-WIDE DURING THE AFTERNOON...HAVE 30-40
POPS GOING ACROSS THE SERN PORTIONS OF THE CWA...CLOSER TO THE MAIN
SFC FRONT WHICH LOOKS TO EXTEND FROM EAST CENTRAL TO SOUTH CENTRAL
PORTIONS OF KS BY TUES EVENING. HAVE SOME LINGERING 20 POPS DURING
THE EVENING HOURS...BUT KEPT THE FORECAST DRY POST-06Z AS THINGS GET
PUSHED FURTHER S/SE. CONFIDENCE IN TEMPS FOR TUESDAY IS NOT
HIGH...AND WILL BE GREATLY AFFECTED BY LINGERING PRECIP/CLOUDS AS
WELL AS THE ULTIMATE LOCATION OF THE SFC BOUNDARY. AT THIS
POINT...HIGHS ARE FORECAST TO REACH THE UPPER 70S TO LOWER 80S.
THE FORECAST FOR WED IS A DRY ONE...WITH THE TUES SYSTEM EXPECTED TO
PUSH OFF TO THE EAST...LEAVING MORE NWRLY /BUT STILL LOW AMPLITUDE/
UPPER LEVEL FLOW IN ITS WAKE. A WEAK SFC PATTERN AND LIGHT WINDS TO
START THE DAY IS EXPECTED TO GIVE WAY TO MORE SOUTHERLY WINDS WITH
TIME...AS SFC LOW PRESSURE BECOMES BETTER ORGANIZED TO OUR WEST
AHEAD OF THE NEXT UPPER LEVEL SYSTEM APPROACHING THE REGION FROM THE
NW. THE LACK OF A NOTABLE CHANGE IN AIR MASS BEHIND THE EARLY WEEK
FRONT LOOKS TO KEEP HIGH TEMPS FOR WED IN THE UPPER 70S/LOWER 80S.
LOOKING AT THE WED NIGHT THROUGH EARLY SAT PERIOD...CONFIDENCE IN
THE FORECAST IS NOT HIGH...AS PLENTY OF DIFFERENCES BETWEEN MODELS
REMAIN. THE LATEST RUN OF THE GFS SHOWS THE POSSIBILITY OF A COUPLE
OF SHORTWAVE DISTURBANCES MOVING THROUGH DURING THIS TIME
FRAME...WHILE THE ECMWF SHOWS A MORE ORGANIZED CLOSED LOW DEVELOPING
BY THURS EVENING OVER THE WRN GREAT LAKES AND PUSHING OFF TO THE
EAST. ONE OF THE RESULTING DIFFERENCES IS THE GFS WOULD BRING A
COUPLE OF SHOTS AT PRECIP...VS THE LIKELY JUST ONE SHOT VIA THE
ECMWF. HAD INHERITED A FEW PERIODS OF POPS IN THIS TIME FRAME...AND
WITH THE GFS STILL SUPPORTING THAT WILL KEEP IT GOING...BUT IF
THINGS TREND TOWARD THE 00Z ECMWF...SOME OF THOSE PERIOD WOULD NEED
TO HAVE POPS REMOVED. WE SHALL SEE. BOTH SOLUTIONS SHOW ANOTHER SFC
COLD FRONT MOVING THROUGH THE REGION...WITH THE ECMWF SHOWING A
BETTER PUSH OF COOLER AIR THAN THE GFS AT THIS POINT. FORECAST HIGHS
REMAIN A BLEND THURS-SAT...DROPPING BACK INTO THE 70S CWA-WIDE.
BETTER AGREEMENT KEEPING SUN DRY...WITH HIGHS REBOUNDING BACK INTO
THE 80S FOR MAINLY THE SWRN THIRD OR SO OF THE CWA.
&&
.AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 550 AM CDT MON SEP 7 2015
LOW LEVEL STRATUS HAS MOVED IN ACROSS THE AREA WITH IFR CIGS
NOW BEING OBSERVED AT BOTH TERMINALS. WITH THIS LOW STRATUS...MAY
NOT SEE VSBYS DROP AS LOW AS PREVIOUSLY THOUGH...BUT WITH A FEW
SITES SHOWING IFR VSBYS...OPTED TO INCLUDE THE MENTION OF BR FOR
SEVERAL HOURS THIS MORNING. OTHERWISE...EXPECT THE STRATUS TO BE
SLOW TO BURN OFF BY LATE MORNING...WITH INCREASING CHANCES FOR
THUNDERSTORMS THEREAFTER. OUTSIDE OF ANY THUNDERSTORM
ACTIVITY...WINDS ARE EXPECTED TO REMAIN FAIRLY LIGHT
TODAY...GENERALLY OUT OF THE EAST OR NORTHEAST AT 10 MPH OR LESS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...ROSSI
LONG TERM...ADP
AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS HASTINGS NE
426 AM CDT MON SEP 7 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 AM CDT MON SEP 7 2015
MOSTLY CLEAR SKIES ARE BEING OBSERVED ACROSS THE LOCAL AREA THIS
MORNING...ALBEIT SOME LOW LEVEL STRATUS HAS BEGUN TO DEVELOP IN
SPOTS. WHILE THIS STRATUS IS PATCHY AT THE MOMENT...EXPECT THIS
STRATUS TO CONTINUE TO SPREAD IN COVERAGE THROUGH DAY BREAK...WITH
SOME LOCALLY DENSE FOG ALSO POSSIBLE THROUGH THE EARLY MORNING
HOURS. THUS FAR...FOG HAS NOT BEEN ABLE TO DEVELOP...BUT WITH DEW
POINT DEPRESSIONS CONTINUING TO SHRINK AND A FEW TEMPS NOW
REACHING THEIR ASSOCIATED DEWPOINT VALUES...CONTINUE TO THINK THE
LATEST HRRR MIGHT BE CORRECT WITH AT LEAST SOME PATCHY DENSE FOG
DEVELOPING AROUND SUNRISE. AS A RESULT...CONTINUED TO MAINTAIN THE
LOWER VISIBILITY WORDING FOR THE MORNING HOURS OF THE FORECAST
AND WILL ALSO CONTINUE TO ADVERTISE IN THE HWO.
WITH SOME CONVECTION ALREADY FORMING ACROSS THE HIGH PLAINS...AND
FAVORABLE UPPER LEVEL JET DYNAMICS EXPECT BY MID
AFTERNOON...EXPECT SOME SHOWERS AND THUNDERSTORMS TO DEVELOP AND
MOVE ACROSS THE REGION...GENERALLY FAVORING AREAS ACROSS SOUTH
CENTRAL NEBRASKA. MODEL SOUNDINGS ARE INDICATIVE OF AMPLE CAPE
ACROSS THE REGION...AND THIS INSTABILITY COMBINED WITH 0-6KM SHEAR
VALUES UPWARDS OF 50KTS EXPECTED LATER IN THE DAY...WOULD NOT BE
SURPRISED TO SEE A FEW STRONG AND ORGANIZED THUNDERSTORMS DEVELOP
ACROSS THE LOCAL AREA. LATEST CONVECTIVE OUTLOOK FROM SPC IS
INDICATIVE OF THIS...WITH THE ENTIRE AREA RIGHT IN THE MIDDLE OF A
MARGINAL RISK FOR SEVERE WEATHER THIS AFTERNOON. AS WITH
YESTERDAY...WHILE THE OVERALL TORNADO THREAT IS FAIRLY LOW...A 2
PERCENT TORNADO RISK IS IN THE LATEST OUTLOOK...AND WILL ADD THIS
MENTION TO THE HWO DESPITE LARGE HAIL AND THUNDERSTORM WIND GUSTS
BEING THE PRIMARY CONCERNS.
TEMPERATURE WISE...EXPECT MOST AREAS TO STRUGGLE TO REACH OR
SLIGHLY EXCEED 80 DEGREES THIS AFTERNOON...WHICH WILL BE A NICE
CHANCE FOR MOST FOLKS. ONCE SKIES CLEAR AND RAINFALL CHANCES
DIMINISH SOME OVERNIGHT...EXPECT A SEASONABLY COOL START TO
TUESDAY FOR THE LOCAL AREA...WITH NEAR TO SLIGHTLY ABOVE SEASONAL
NORMS FOR LOW TEMPERATURES...WITH FORECAST LOWS GENERALLY FALLING
INTO THE UPPER 50S ACROSS OUR NORTH...AND INTO THE LOWER TO MIDDLE
60S ACROSS NORTH CENTRAL KANSAS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 405 AM CDT MON SEP 7 2015
PRIMARY FORECAST CONCERN THROUGH THE LONG TERM LIES WITH
PRECIPITATION CHANCES.
THE START OF THE PERIOD SHOWS MODELS NOT IN TOO BAD OF AGREEMENT
WITH THE OVERALL UPPER LEVEL PATTERN...WITH THE CWA UNDER ZONAL TO
SLIGHTLY SWRLY FLOW...THANKS TO BROAD TROUGHING CONNECTED TO A LOW
PRESSURE SYSTEM LOCATED OVER NORTH CENTRAL CANADA. AT THE
SFC...STILL EXPECTING THERE TO BE A FRONTAL BOUNDARY MEANDERING
AROUND THE AREA...THOUGH EXACT PLACEMENT IS UNCERTAIN AS IT WILL
LIKELY BE AFFECTED BY ANY THUNDERSTORMS MOVING THROUGH TONIGHT.
CONTINUE TO HAVE POPS RIGHT OFF THE BAT TUESDAY MORNING...LINGERING
ACTIVITY FROM TONIGHT...WHICH IS EXPECTED TO BE SLIDING OFF TO THE
EAST WITH A GRADUALLY VEERING/WANING LLJ. THINKING IS THAT THERE
WILL BE AT LEAST A BIT OF A BREAK IN ACTIVITY LATER IN THE MORNING
PERHAPS INTO THE EARLY AFTERNOON HOURS...BUT ANOTHER LOBE OF
SHORTWAVE ENERGY ASSOCIATED WITH THAT UPPER LEVEL CANADIAN LOW IS
EXPECTED TO MOVE INTO THE AREA FROM THE NW LATE IN THE
AFTERNOON...PROVIDING THE OPPORTUNITY FOR ADDITIONAL THUNDERSTORMS.
WHILE KEPT POPS IN PLACE CWA-WIDE DURING THE AFTERNOON...HAVE 30-40
POPS GOING ACROSS THE SERN PORTIONS OF THE CWA...CLOSER TO THE MAIN
SFC FRONT WHICH LOOKS TO EXTEND FROM EAST CENTRAL TO SOUTH CENTRAL
PORTIONS OF KS BY TUES EVENING. HAVE SOME LINGERING 20 POPS DURING
THE EVENING HOURS...BUT KEPT THE FORECAST DRY POST-06Z AS THINGS GET
PUSHED FURTHER S/SE. CONFIDENCE IN TEMPS FOR TUESDAY IS NOT
HIGH...AND WILL BE GREATLY AFFECTED BY LINGERING PRECIP/CLOUDS AS
WELL AS THE ULTIMATE LOCATION OF THE SFC BOUNDARY. AT THIS
POINT...HIGHS ARE FORECAST TO REACH THE UPPER 70S TO LOWER 80S.
THE FORECAST FOR WED IS A DRY ONE...WITH THE TUES SYSTEM EXPECTED TO
PUSH OFF TO THE EAST...LEAVING MORE NWRLY /BUT STILL LOW AMPLITUDE/
UPPER LEVEL FLOW IN ITS WAKE. A WEAK SFC PATTERN AND LIGHT WINDS TO
START THE DAY IS EXPECTED TO GIVE WAY TO MORE SOUTHERLY WINDS WITH
TIME...AS SFC LOW PRESSURE BECOMES BETTER ORGANIZED TO OUR WEST
AHEAD OF THE NEXT UPPER LEVEL SYSTEM APPROACHING THE REGION FROM THE
NW. THE LACK OF A NOTABLE CHANGE IN AIR MASS BEHIND THE EARLY WEEK
FRONT LOOKS TO KEEP HIGH TEMPS FOR WED IN THE UPPER 70S/LOWER 80S.
LOOKING AT THE WED NIGHT THROUGH EARLY SAT PERIOD...CONFIDENCE IN
THE FORECAST IS NOT HIGH...AS PLENTY OF DIFFERENCES BETWEEN MODELS
REMAIN. THE LATEST RUN OF THE GFS SHOWS THE POSSIBILITY OF A COUPLE
OF SHORTWAVE DISTURBANCES MOVING THROUGH DURING THIS TIME
FRAME...WHILE THE ECMWF SHOWS A MORE ORGANIZED CLOSED LOW DEVELOPING
BY THURS EVENING OVER THE WRN GREAT LAKES AND PUSHING OFF TO THE
EAST. ONE OF THE RESULTING DIFFERENCES IS THE GFS WOULD BRING A
COUPLE OF SHOTS AT PRECIP...VS THE LIKELY JUST ONE SHOT VIA THE
ECMWF. HAD INHERITED A FEW PERIODS OF POPS IN THIS TIME FRAME...AND
WITH THE GFS STILL SUPPORTING THAT WILL KEEP IT GOING...BUT IF
THINGS TREND TOWARD THE 00Z ECMWF...SOME OF THOSE PERIOD WOULD NEED
TO HAVE POPS REMOVED. WE SHALL SEE. BOTH SOLUTIONS SHOW ANOTHER SFC
COLD FRONT MOVING THROUGH THE REGION...WITH THE ECMWF SHOWING A
BETTER PUSH OF COOLER AIR THAN THE GFS AT THIS POINT. FORECAST HIGHS
REMAIN A BLEND THURS-SAT...DROPPING BACK INTO THE 70S CWA-WIDE.
BETTER AGREEMENT KEEPING SUN DRY...WITH HIGHS REBOUNDING BACK INTO
THE 80S FOR MAINLY THE SWRN THIRD OR SO OF THE CWA.
&&
.AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1243 AM CDT MON SEP 7 2015
CLEARING SKIES EARLY THIS MORNING COMBINED WITH ELEVATED
DEWPOINTS AND LIGHT NORTHEASTERLY WINDS...WILL RESULT IN THE
FORMATION OF AT LEAST IFR CIGS/VSBYS TOWARDS 07/10Z. THIS FOG IS
EXPECTED TO LINGER FOR SEVERAL HOURS...BEFORE CONDITIONS IMPROVE
AFT 07/15Z...OR THEREABOUTS. OTHERWISE...EXPECT THE PRESENCE OF AN
OLD FRONTAL BOUNDARY NEAR THE SURFACE AND UPPER LEVEL DISTURBANCE TO
PROVIDE THE FOCUS FOR AFTERNOON SHOWER AND THUNDERSTORM
DEVELOPMENT...AND OPTED TO INTRODUCE THE CHANCE FOR A VCTS DURING
THE LATE AFTERNOON THROUGH EVENING HOURS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...ROSSI
LONG TERM...ADP
AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
400 AM CDT MON SEP 7 2015
.SYNOPSIS...
ISSUED AT 356 AM CDT MON SEP 7 2015
LARGE UPPER LOW LOCATED OVER SRN CANADA WITH TROUGH AXIS SWD INTO
MT AND ID...WITH NOTABLE PV ANOMALY MOVING THROUGH THE BASE OF
THE TROUGH OVER NRN NV. ZONE OF HIGHER SWRLY FLOW ALOFT LOCATED
AHEAD OF THIS UPPER TROUGH FROM MN TO SRN CA...RUNNING THROUGH
THE NWRN CORNER OF NEB. ALONG THIS SWRLY FLOW ALOFT...WEAK SHORT
WAVES CONTINUE TO PROGRESS QUICKLY NEWD AS THEY HAVE THE PAST FEW
DAYS. SFC FRONT THAT MOVED THROUGH THE AREA THIS MORNING LOCATED
FROM SRN IA ACROSS NERN KS SWWD TO NEAR DDC. THIS FRONT MARKED BY
CONVECTION FROM SRN IA INTO NERN KS. ON THE NORTH SIDE OF THIS
FRONT...ERLY UPSLOPE FLOW EXISTS AT THE SFC WITH NERLY WIND AT
500M/1KM AT KLNX. SFC WINDS HAVE TURNED SERLY ALREADY FROM THE
PANHANDLE INTO NWRN KS AND THIS IS CONTRIBUTING TO TSRA
DEVELOPMENT ACROSS WRN NEB. VSBYS STARTING TO BE REDUCED IN THE
ONL AREA DUE TO FOG.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 356 AM CDT MON SEP 7 2015
FOR THIS MORNING...TSRA DEVELOPING AND MOVING EWD ALONG GRADIENT
OF STEEPER LAPSE RATES ALOFT AND WILL LIKELY BE SUSTAINED AS
ELEVATED INSTABILITY EXPANDS EWD IN INCREASING ISENTROPIC
UPGLIDE. CIRA LOW CLOUD/FOG PRODUCT SHOWING ONLY LIMITED
DEVELOPMENT OF LOW CLOUDS AS EXPECTED BY SHORT RANGE MODELS AND
SREF PROBABILITY GUIDANCE. WILL CONTINUE THE IDEA OF PATCHY FOG
THOUGH CONVECTIVE TRENDS SO FAR WOULD SUGGEST FURTHER FOG
DEVELOPMENT MAY BE INHIBITED SOMEWHAT.
PREVIOUSLY MENTIONED PV ANOMALY OVER NRN NV WILL CONTINUE TO
ROTATE NEWD TODAY AND AS THE ENTIRE TROUGH PULLS EWD...UPPER
LEVEL JET DEVELOPMENT OCCURS IN CONFLUENT ZONE OVER WY TODAY.
THIS WILL PUT THE RIGHT ENTRANCE REGION OF THE NEWLY DEVELOP JET
STREAK OVER WRN NEB BY AFTERNOON. THE RESULTING DIRECT THERMAL
CIRCULATION THAT IS ALREADY DEVELOPING IN RESPONSE OVER THE HIGH
PLAINS...AS EVIDENCED BY ISENTROPIC LIFT ON THE 310/315K
SFC...WILL INDUCE A NWRLY LOW LEVEL AGEOSTROPHIC FLOW AND ENHANCE
FRONTOGENSIS ACROSS THE WRN PORTION OF THE AREA THIS AFTERNOON.
AS THIS OCCURS IN A REGION OF DECENT MID LEVEL INSTABILITY...NEW
TSRA SHOULD DEVELOP THIS AFTERNOON IN WRN NEB AND MOVE EWD. CAPE
IS NOT EXTREME BUT WITH GOOD SHEAR IN PLACE THROUGH A DEEP LAYER
SOME POTENTIAL FOR LARGE HAIL WILL EXIST WITH ANY STORMS THAT DO
DEVELOP...HENCE THE MARGINAL RISK AS DEPICTED BY SPC. THE FLY IN
THE OINTMENT HERE WOULD BE ONGOING CONVECTION AND CONVECTIVE
DEBRIS THAT REMAIN FROM THIS MORNINGS CONVECTION AND HOW THAT
AFFECTS THE ATMOSPHERE BY THIS AFTERNOON. CLOUD COVER MAY
NEGATIVELY AFFECT THE STORMS BEING ABLE TO REALIZE AVAILABLE
CAPE...BUT LEFT OVER BOUNDARIES MAY BE A FOCUS FOR UPWARD
VERTICAL MOTION ENHANCEMENT TO POSITIVELY INFLUENCE INDIVIDUAL
UPDRAFTS...SO ANOTHER COMPLICATED FCST REMAINS. SHORT RANGE
MODELS AND CAM ENSEMBLES AGAIN SUGGEST A WIDE RANGE OF POSSIBLE
SOLUTIONS. ALTHOUGH THE HRRR HAS HAD ITS STRUGGLES LATELY...THINK
IT MIGHT BE ON TO THE RIGHT IDEA DEVELOPING TSRA IN THE 3-4PM CDT
TIME RANGE. THIS IDEA IS ALSO SUPPORTED BY THE NSSL WRF AND BY A
FEW MEMBERS OF THE NCAR 10 MEMBER 3KM WRF ENSEMBLE. THE POPS FCST
IS THEREFORE LIMITED TO THE CHC RANGE FOR NOW.
FOG/LOW CLOUDS MAY BE POSSIBLE AGAIN TONIGHT AND IS SHOWN IN SOME
OF THE MOS GUIDANCE AS WELL AS THE 07.03Z SREF. ULTIMATE
DEVELOPMENT HOWEVER WILL DEPEND ON THE CONVECTIVE TRENDS
OVERNIGHT...SO CONFIDENCE WAS NOT HIGH ENOUGH TO INCLUDE IN THE
FCST AT THIS POINT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 356 AM CDT MON SEP 7 2015
CHILLY TUESDAY WITH LINGERING MORNING SHOWERS GIVING WAY TO
PARTLY SUNNY SKIES. COOL HIGH PRESSURE BUILDS ACROSS THE AREA AND
BATTLE BETWEEN CAA AND SEPTEMBER SUN. THE BIGGEST THING TO WATCH
IS HOW SOON CLOUDS DISSIPATE...WHICH WILL HAVE A DIRECT IMPACT ON
HIGHS. MOST AREAS HOLD IN THE 70S...EXCEPT FOR FAR SW WITH HIGHS
AROUND 80...ALTHOUGH AN EARLIER CLEARING WILL BUMP UP TEMPS A
GOOD 5 DEGREES OR MORE.
BL MOISTURE WILL BE A CONCERN TUESDAY NIGHT INTO WED MORN. THE
NAM WHICH HAS MORE BL MOISTURE SUGGESTS STRATUS/FOG COULD DEVELOP
WITH WINDS BECOMING SOUTHEASTERLY/SOUTHERLY ON THE BACK SIDE OF
THE SFC HIGH. THE GFS/EC MOS GUIDANCE IS DRIER AND KEEPS THINGS
CLEAR AND HAS SLIGHTLY LOWER TEMPS. MODELS HAVE BEEN STRUGGLING
WITH LOW LEVEL MOISTURE...WHICH LEADS TO LOW CONFIDENCE IN
WHETHER FOG/STRATUS WILL DEVELOP OR NOT.
WEDNESDAY WILL SEE THE NEXT WEAK COLD FRONT PUSH ACROSS THE AREA.
SLIGHT WARM UP AHEAD OF THE FRONT WITH MOST HIGHS AROUND 80 INTO
THE MID 80S. MODELS HAVE BEEN IN GOOD AGREEMENT DEVELOPING A LINE
OF STORMS ALONG THE BOUNDARY WHICH MODEL BLENDS PLACE ACROSS THE
HEART /FROM NORTHEAST TO SOUTHWEST/ OF THE CWA DURING PEAK
HEAT/INITIATION. SHEAR IS WEAK HOWEVER A NARROW BAND WITH CAPE
VALUES OF 500 TO 1000 J/KG SO EXPECT AT LEAST SOME ISOLD THUNDER.
HIGH PRESSURE BRINGS DRY AIR FOR THURSDAY. HIGH QUICKLY MOVES
EAST FOR FRIDAY WITH RETURN SOUTHERLY FLOW TO BRING AN INCREASE
OF MOISTURE. SOME AFTERNOON INSTABILITY DEVELOPS THEN A LL JET
KICKS IN OVERNIGHT. RESULTS IN AT LEAST A SLGHT CHANCE FOR
PRECIP FRIDAY INTO FRIDAY NIGHT. INBETWEEN SYSTEMS FOR THE
WEEKEND WITH SEASONAL AND DRY CONDITIONS EXPECTED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1144 PM CDT SUN SEP 6 2015
THE POTENTIAL FOR FOG/STRATUS IS THE FIRST AVIATION CONCERN
TONIGHT AND EARLY MONDAY. EAST TO NORTHEAST WIND WILL BRING MORE
MOISTURE UP THE PLATTE RIVER VALLEY POSSIBLY AS FAR WEST AS OGA
BUT LIKELY TO REACH LBF. WE HAVE SOME CONFIDENCE THAT INSTRUMENT
METEOROLOGICAL CONDITIONS WILL REACH LBF AND BBW BUT ONLY WEAK
CONFIDENCE THAT IT WILL REACH ANY FARTHER WEST. IF IT IS STRATUS
THAT COMES IN...THE CEILING IS LIKELY TO BE LESS THAN 1000 FEET
WHILE...IF STRATUS DOES NOT COME...VISIBILITY IS LIKELY TO BE
LESS THAN 3SM.
SHORT TERM OUTPUT FROM ONLY TWO OF THE FIVE MODEL CYCLES GIVES
SOME WEAK INSTABILITY AHEAD OF A WEAK UPPER SYSTEM...SO THERE IS
A POSSIBILITY OF SHOWERS OR THUNDERSTORMS EARLY MONDAY.
HOWEVER...THE DIFFERENCES IN THE MODEL OUTPUT PARES OUR
CONFIDENCE TO LESS THAN THIRTY PERCENT THAT THIS WILL OCCUR.
LOOKING A LITTLE FARTHER OUT...IT IS POSSIBLE THAT SOME STRONG
THUNDERSTORMS WILL DEVELOP LATE AFTERNOON OR EARLY EVENING THOUGH
THERE IS CONSIDERABLE UNCERTAINTY WITH THE TIMING AND THE
LOCATION. CONSIDERING THE MODEL OUTPUT STATISTICS...ONE BULLETIN
INDICATES 20-40 PERCENT PROBABILITY BOTH MONDAY MORNING AND
MONDAY EVENING FOR BBW AND LBF AND THE OTHER GIVES THE 20-40
PERCENT PROBABILITY TO THE EVENING ONLY. THUS THE RESULT IS
THAT...IF I WERE TO PICK THE TIMING...I WOULD FOCUS ON THE
EVENING AFTER 23Z.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JWS
SHORT TERM...JWS
LONG TERM...MASEK
AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1258 AM CDT MON SEP 7 2015
.UPDATE...
ISSUED AT 1243 AM CDT MON SEP 7 2015
WINDS ARE SHIFTING EARLY THIS MORNING AND BECOMING MORE
NORTHEASTERLY...HELPING TO ADVECT IN HIGHER DEWPOINTS FROM THE
NORTHEAST. THIS MORE HUMID AIR...COMBINED WITH CLEARING SKIES AND
FALLING TEMPERATURES...SHOULD ALLOW FOR THE FORMATION OF AT LEAST
AREAS OF FOG DURING THE EARLY MORNING HOURS. LATEST/04Z RUN OF
THE HRRR INDICATES WE COULD SEE WIDESPREAD DENSE FOG AROUND
SUNRISE...BUT OPTED TO ONLY UPDATE FORECAST TO INDICATE
VISIBILITIES FALLING TO 1 SM FOR THE TIME BEING...BUT WILL NEED
TO CONTINUE TO MONITOR IN CASE MORE DENSE FOG DOES INDEED FORM
OVERNIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 345 PM CDT SUN SEP 6 2015
ALOFT: THE PERSISTENT WRN USA TROF/ERN USA RIDGE WILL REMAIN THRU
TOMORROW...BUT DEAMPLIFICATION WAS UNDERWAY. THE DEEP WRN USA TROF
WILL BECOME MORE BROAD AS THE LOW THAT WAS STALLED OVER THE PAC NW
THIS PAST WEEK HEADS NE INTO CNTRL CANADA. QUIET SW FLOW WILL
REMAIN OVER THE CNTRL PLAINS. HOWEVER...THERE WERE A COUPLE WEAK
SHORTWAVE TROFS OVER WA AND NRN CA. AS THESE TROFS CROSS THE NRN
ROCKIES TONIGHT AND N OF THE FCST AREA TOMORROW...THIS WILL FORCE
THE UPR- LVL JET STREAK TO THE E PUTTING THE FCST AREA IN THE RRQ.
MASS ADJUSTMENT/LIFT SHOULD CREATE AN INCREASINGLY FAVORABLE
ENVIRONMENT FOR TSTMS MON AFTERNOON.
SURFACE: THE COOL FRONT THAT WAS QUASI-STATIONARY WELL NW OF THE
FCST AREA THIS PAST WEEK WAS NOW MOVING THRU. AS IT BECOMES
PARALLEL TO THE FLOW ALOFT...ITS FWD PROGRESS WILL SLOW AND IT
WILL BECOME QUASI-STATIONARY JUST S AND E OF THE FCST AREA
TONIGHT. SOME MODELS SUGGEST IT COULD LIFT BACK N INTO S-CNTRL NEB
TOMORROW...BUT THERE IS DISAGREEMENT ON THIS.
NOW THRU EARLY EVE: HOT S AND E OF THE TRI-CITIES. THE COOL FRONT
CURRENTLY EXTENDS FROM COLUMBUS-AURORA-SMITH CENTER-PLAINVILLE KS.
WE COULD SEE AN ISOLATED STORM OR TWO DEVELOP...PROBABLY SOMEWHERE
FROM GENEVA-YORK-BELOIT. CAN`T RULE OUT A SVR STORM WITH MLCAPE
2000-2500 J/KG...BUT EFFECTIVE SHEAR IS ONLY 25 KTS.
TONIGHT: ANY STORMS WILL EXIT EARLY...PROBABLY BY 6 OR 7 PM. WE
NEED TO WATCH DEVELOPMENT OF POST-FRONTAL STRATUS. OBS SHOW MVFR
CIGS OVER ERN SD AT 20Z. THE NAM 500M DWPT DEPRESSIONS SUGGEST
STRATUS FORMS AND SPREADS W ACROSS NEB TONIGHT. EC/GFS/NAM CROSS
SECTIONS ALL HAVE IT TO SOME EXTENT. SO EXPECT INCREASING CLOUDS.
EVEN IF STRATUS DOESN`T MATERIALIZE...EXPECT EXTENSIVE
CIRROSTRATUS/ALTOCU TO OVERTAKE THE AREA AFTER MIDNIGHT FROM THE
SW.
MON: MODELS ARE TRYING TO DEVELOP HIGH-BASED SHWRS/TSTMS OVER ERN
CO LATE TONIGHT...AND BRINGING THEIR REMNANTS E INTO THE FCST AREA
DURING THE MORNING. CONFIDENCE IS LOW ON THIS. IT COULD END UP
JUST MID-LVL SPRINKLES FROM ACCAS.
MODELS SUGGEST SCT TSTMS DEVELOP IN THE AFTERNOON AND THIS SEEMS
REASONABLE WITH THE JET DYNAMICS ACTING ON THE FRONT. CLOUD COVER
WILL BE A BIG PLAYER IN HOW TSTMS DEVELOP/EVOLVE. 15Z/SREF FCSTS
MLCAPE 3000-4000 J/KG...BUT THE SREF COULD BE 3-4F TOO HIGH WITH
ITS DWPTS. REGARDLESS...DEEP LAYER SHEAR OF 30-40 KTS WILL SUPPORT
ORGANIZED/SUSTAINED UPDRAFTS AND POTENTIAL FOR SVR TSTMS.
WITH BACKED WINDS N OF THE WARM FRONT...IF ANY STORMS CAN REMAIN
DISCRETE AND FORM ON OR JUST N OF THE FRONT AND/OR DEVELOP IN THE
WARM SECTOR AND CROSS THE FRONT...A TORNADO OR TWO WOULD BE
POSSIBLE.
SPC INDICATED IN THE SWODY2 THAT AN UPGRADE TO SLGT RISK MAY
BE NECESSARY. HAVE ALREADY INDICATED POTENT SVR IN THE HWO IN
ANTICIPATION OF THIS.
TEMPS A TOUGH CALL. THEY WILL DEPEND ON CLOUD COVER. IF STRATUS
REMAINS LOCKED BELOW THE FRONTAL INVERSION...SOME AREAS MAY NOT
GET OUT OF THE 70S. IT COULD REALLY HEAT UP AGAIN S OF THE FRONT.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 345 PM CDT SUN SEP 6 2015
GUIDANCE SUGGESTS A CLOSED UPPER TROPOSPHERIC LOW WILL EXIST OVER
WESTERN AND CENTRAL PORTIONS OF CANADA TO START THE LONG-TERM
FORECAST PERIOD AT 00Z TUESDAY...WITH AN ASSOCIATED TROUGH LIKELY
EXTENDING SOUTH/SOUTHWEST FROM THE LOW INTO PORTIONS OF THE
NORTHWESTERN CONUS. THIS UPPER TROPOSPHERIC LOW IS EXPECTED TO
MOVE EAST TUESDAY AND WEDNESDAY BEFORE BECOMING STATIONARY OVER
THE HUDSON BAY THURSDAY AND FRIDAY. THIS SHOULD ALLOW THE UPPER
TROPOSPHERIC TROUGH OVER THE NORTHWESTERN CONUS TO ALSO MOVE EAST
ACROSS THE NORTHERN PLAINS...AND PORTIONS OF THE CENTRAL
PLAINS...TUESDAY AND WEDNESDAY. AN UPPER TROPOSPHERIC SHORT
WAVE...MOVING SOUTHEAST ALONG THE BACKSIDE OF THE LOW...IS THEN
EXPECTED TO DIVE SOUTHEAST ACROSS THE NORTHERN AND CENTRAL PLAINS
ON THURSDAY...WITH YET ANOTHER SHORT WAVE EXPECTED TO DO THE SAME
ON FRIDAY. THIS PARADE OF SHORT WAVES SHOULD THEN CEASE SATURDAY
AND SUNDAY AS THE LOW OVER THE HUDSON BAY MOVES EAST/NORTHEAST AND
SUBTLE UPPER TROPOSPHERIC RIDGING OVERTAKES THE CENTRAL CONUS.
UPPER TROPOSPHERIC THERMAL ADVECTION AHEAD OF THE TROUGH ON
TUESDAY AND WEDNESDAY COULD BE SUFFICIENT FOR PRECIPITATION
PRODUCTION ACROSS MUCH OF OUR AREA MONDAY NIGHT INTO EARLY
WEDNESDAY...A SOLUTION SUPPORTED BY QPF FIELDS FROM THE
NAM...OPERATIONAL GFS AND EC. GIVEN THIS...POPS REMAIN INTACT
ACROSS MUCH OF THE CWA MONDAY NIGHT THROUGH VERY EARLY WEDNESDAY.
THE PASSAGE OF THE NEXT TWO SHORT WAVES WILL THEN PROMOTE
ADDITIONAL UPPER TROPOSPHERIC THERMAL ADVECTION AND RESULTANT
OMEGA THURSDAY AND FRIDAY...AND POPS REMAIN INTACT ACROSS MUCH OF
THE CWA ON BOTH OF THESE DAYS AS WELL. DRY CONDITIONS ARE THEN
FORECAST SATURDAY AND SUNDAY AS AN OVERALL LACK IN OMEGA OVERTAKES
THE AREA.
NEAR-NORMAL TEMPERATURE READINGS...WITH HIGHS NEAR 80 AND LOWS IN
THE MID TO UPPER 50S...ARE CURRENTLY EXPECTED DURING THE MIDDLE
PART OF NEXT WEEK...BUT THE INFILTRATION OF A MUCH COOLER AIR MASS
WILL LIKELY RESULT IN BELOW-NORMAL TEMPERATURE READINGS THURSDAY
AND BEYOND...WITH HIGHS GENERALLY IN THE 70S AND LOWS NEAR 50
EXPECTED.
&&
.AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1243 AM CDT MON SEP 7 2015
CLEARING SKIES EARLY THIS MORNING COMBINED WITH ELEVATED
DEWPOINTS AND LIGHT NORTHEASTERLY WINDS...WILL RESULT IN THE
FORMATION OF AT LEAST IFR CIGS/VSBYS TOWARDS 07/10Z. THIS FOG IS
EXPECTED TO LINGER FOR SEVERAL HOURS...BEFORE CONDITIONS IMPROVE
AFT 07/15Z...OR THEREABOUTS. OTHERWISE...EXPECT THE PRESENCE OF AN
OLD FRONTAL BOUNDARY NEAR THE SURFACE AND UPPER LEVEL DISTURBANCE TO
PROVIDE THE FOCUS FOR AFTERNOON SHOWER AND THUNDERSTORM
DEVELOPMENT...AND OPTED TO INTRODUCE THE CHANCE FOR A VCTS DURING
THE LATE AFTERNOON THROUGH EVENING HOURS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...ROSSI
SHORT TERM...HALBLAUB
LONG TERM...BRYANT
AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
302 PM MDT MON SEP 7 2015
.SYNOPSIS...
STORMS WILL CONTINUE THIS EVENING LARGELY FOR AREAS SOUTH OF
INTERSTATE 40 WHERE SPOTTY LOCATIONS MAY SEE A HALF INCH OR MORE
OF RAIN. A BACK DOOR COLD FRONT WILL SLIDE DOWN THE PLAINS
TUESDAY AND TUESDAY NIGHT BEFORE PUSHING THROUGH THE GAPS OF THE
CENTRAL MOUNTAIN CHAIN WEDNESDAY MORNING. SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE BEHIND THE FRONT ACROSS THE PLAINS.
TEMPERATURES WILL COOL IN THE WAKE OF THE FRONT...BUT WILL STILL
BE RIGHT AROUND NORMAL VALUES FOR EARLY SEPTEMBER WEDNESDAY
AFTERNOON. MID LEVEL DRY AIR WILL CONTINUE TO PUSH INTO THE STATE
ON THURSDAY AND FRIDAY...BUT ANOTHER BACK DOOR FRONT WILL BE
LURKING AS WELL.
&&
.DISCUSSION...
MOST OF THE RATHER WELL-BEHAVED STORMS TODAY HAVE STAYED SOUTH OF
I-40 AS EXPECTED. HRRR SUGGESTS THAT THE ABQ METRO AREA MAY SEE
SOME ACTION SHORTLY AFTER 00Z...BUT MOST OF THE ACTIVITY SHOULD
END BY MIDNIGHT ACROSS ALL AREAS.
STILL LOOKING FOR A BACK DOOR COLD FRONT TO MOVE INTO AT LEAST NE
NM ON TUESDAY BEFORE SLIDING SOUTH AND WEST TUESDAY NIGHT. THE
FRONT CONTINUES TO LOOK STRONGER WITH EACH MODEL RUN...AND A
BREEZY EAST CANYON WIND NOW LOOKS MORE LIKELY EARLY WEDNESDAY
MORNING FOR THE RIO GRANDE VALLEY. THE BIGGEST QUESTION CONTINUES
TO BE HOW MUCH PRECIPITATION WILL ACCOMPANY THE FRONT. GFS
CONTINUES TO BE VERY BULLISH BREAKING OUT STORMS ACROSS MUCH OF
EASTERN NM IN MOIST UPSLOPE FLOW TUESDAY NIGHT. OTHER MODELS ARE
LESS ENTHUSED. IT CERTAINLY SEEMS POSSIBLE SINCE MODELS ARE NOT
SHOWING AS MUCH DRYING AT MID LEVELS AS THEY WERE
YESTERDAY...EXCEPT FOR IN THE FAR NW. GIVING A NOD TO THE GFS
ENSEMBLE MEMBERS...WHICH ARE MUCH LIKE THEIR OPERATIONAL
COUNTERPART... BUMPED UP POPS A BIT MORE ACROSS THE EAST.
MOST MODELS NOW SHOWING CONVECTION ALONG THE CENTRAL MTN CHAIN ON
WEDNESDAY AFTERNOON WITH CONTINUED MOIST UPSLOPE FLOW. STORMS
SHOULD BE MORE ROBUST SOUTH OF I-40 WHERE MID LEVEL DRYING IS NOT
AS PREVALENT. HIGH TEMPERATURES ON WEDNESDAY SHOULD DROP AT LEAST
3 TO 8 DEGREES FROM TUESDAYS READINGS...THOUGH THIS WILL MEAN
TEMPS WILL ACTUALLY BE RIGHT AROUND NORMAL.
THE MID LEVEL DRY AIR NUDGES IN FARTHER ON THURSDAY...AND
CONVECTIVE COVERAGE SHOULD WANE A BIT. AREAS SOUTH OF HWY 60
SHOULD HAVE THE BEST STORM CHANCES. THEREAFTER...CONFIDENCE
REMAINS VERY LOW AS MODELS CONTINUE TO YO-YO THE NEXT BACK DOOR
FRONT AROUND. THE ECMWF IS BACK ON SCHEDULE FOR THE FRONT TO
ARRIVE ON FRIDAY...WHILE THE GFS IS AROUND 12 HOURS LATER AND ALSO
MUCH STRONGER. THIS WILL OBVIOUSLY HAVE SERIOUS IMPLICATION ON
POPS AND TEMPS...SO GENERALLY WENT FOR A MIDDLE OF THE ROAD
FORECAST FOR NOW.
34
&&
.FIRE WEATHER...
HIGH PRESSURE ALOFT IS FORECAST TO BUILD INTO THE GREAT BASIN THIS
WEEK...EVENTUALLY CUTTING OFF THE FLOW OF MOISTURE FROM THE
SOUTH...WHILE SHUNTING HURRICANE LINDA WEST OF BAJA CA/SOCAL. THIS
SHOULD LEAD TO A DRYING TREND FOR WESTERN NEW MEXICO. LOW LEVEL
MOISTURE WILL SLOSH BACK AND FORTH OVER CENTRAL AND EASTERN NEW
MEXICO THIS WEEK...DEPENDING ON TIMING OF 2 BOUNDARIES...ONE
EXPECTED TUESDAY/TUESDAY NIGHT AND A SECOND...WHICH THE GFS IS NOW
PORTRAYING AS STRONGER THAN IT HAS IN SEVERAL RUNS...ON
FRIDAY/FRIDAY NIGHT.
SO FAR THIS AFTERNOON...MOST OF THE CONVECTION HAS BEEN RELEGATED TO
AREAS ALONG AND SOUTH OF INTERSTATE 40...AS THE HRRR SUGGESTED.
WETTING RAIN FOOTPRINTS TO BE FAIRLY SMALL AS CELLS TRACK TO THE
EAST/NORTHEAST...AND ACTIVITY IS INDICATED TO DIMINISH BY MID
EVENING.
TUESDAY/WEDNESDAY ARE TRANSITION DAYS IN WHICH THE UPPER AIR PATTERN
SHIFTS FROM WEST TO NORTHWEST/NORTH WINDS ALOFT...IMPORTING
CONSIDERABLY DRIER AIR AT THE MID LEVELS. THE SURFACE BOUNDARY FOR
TUESDAY/TUESDAY NIGHT APPEARS A BIT MORE VIGOROUS AND MAY PUSH SOME
LOW LEVEL MOISTURE INTO THE RGV...WHICH MIXES OUT TO SOME EXTENT
WEDNESDAY...WHEN BEST CHANCES FOR WETTING RAIN WILL BECOME FOCUSED
ALONG THE CENTRAL MT CHAIN AND SOUTH OF I-40. PRECIPITATION CHANCES
TAPER DOWN THURSDAY INTO FRIDAY...BUT ANOTHER BOUNDARY COULD
REPLENISH LOW LEVEL MOISTURE INTO THE CENTRAL/EAST BY SATURDAY.
TOWARDS THE END OF THIS WEEK...AND INTO NEXT WEEK...FORECAST
VARIABLES CONTINUE TO BE QUITE VARIABLE WITH RUN TO RUN MODEL FLIP
FLOPPING. THE 12Z GFS DEVELOPS A VIGOROUS SHORT WAVE/CLOSED LOW ON
THE EASTERN PERIPHERY OF THE UPPER RIDGE OVER ERN NM/CHIHUAHUA THIS
WEEKEND THEN EJECTS IT NEWD EARLY NEXT WEEK. THE ECMWF HAS OTHER
IDEAS...MAINLY A 590 PLUS HIGH CENTER OVER NM. IN FACT...THE DEEP
UPPER TROF DEPICTED 24 HRS AGO BY BOTH NEAR 240 HRS HAS VANISHED.
KEEPING THE LOW CONFIDENCE IN MIND...HIGH HAINES WILL BE FOUND OVER
PORTIONS OF CENTRAL AND WRN NM MID TO LATE THIS WEEK. POOR OVERNIGHT
RECOVERIES WILL PLAGUE PORTIONS OF THE NW DURING THIS TIME...AND MIN
RH VALUES MAY FALL BELOW 15 PERCENT. HIGHS WILL BE CLOSE TO AVERAGE
FOR THE SEASON THROUGH THE UPCOMING WEEKEND. OVERNIGHT LOWS MAY FALL
TO NEAR FREEZING AT SOME OF THE NRN MT HIGHER TERRAIN OBS SITES MID
TO LATE WEEK. VENT RATES FORECAST TO BE GOOD TO EXCELLENT
TUESDAY...THEN DECREASE WEDNESDAY WITH AREAS OF FAIR TO POOR
FORECAST ALONG AND SOUTH OF I-40. WIDESPREAD FAIR TO POOR RATES
ANTICIPATED FRIDAY CENTRAL AND EAST.
&&
.AVIATION...
18Z TAF CYCLE
IN GENERALLY WLY STEERING FLOW FOR CONVECTION. SHORT TERM MODELS
SUGGEST A DRIER ENVIRONMENT NW AND NORTH CENTRAL NM WITH SCT
SHOWERS AND STORMS ALONG AND SOUTH OF INTERSTATE 40 BEFORE 06Z.
THE STRONGER STORMS WILL PRODUCE BRIEF MODERATE TO HEAVY RAIN WITH
LCL MVFR CIGS/VSBYS AND OCCASIONAL MT OBSCURATIONS AS WELL AS WND
GUSTS TO 40KT. OTHERWISE VFR.
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 56 87 52 87 / 5 0 0 0
DULCE........................... 42 81 40 80 / 5 10 5 10
CUBA............................ 50 79 47 77 / 10 5 5 10
GALLUP.......................... 51 84 45 84 / 20 10 0 0
EL MORRO........................ 49 79 45 79 / 30 20 10 10
GRANTS.......................... 50 82 47 83 / 30 10 5 5
QUEMADO......................... 52 79 50 80 / 30 20 10 20
GLENWOOD........................ 58 86 58 85 / 20 30 20 20
CHAMA........................... 44 77 42 77 / 10 10 10 20
LOS ALAMOS...................... 59 80 55 79 / 20 5 5 10
PECOS........................... 56 79 53 75 / 20 10 10 30
CERRO/QUESTA.................... 51 77 48 75 / 5 10 10 20
RED RIVER....................... 41 70 43 68 / 10 20 20 30
ANGEL FIRE...................... 48 70 45 69 / 10 20 20 20
TAOS............................ 47 80 46 78 / 0 10 5 20
MORA............................ 53 76 49 73 / 20 20 20 20
ESPANOLA........................ 53 85 53 84 / 10 0 0 5
SANTA FE........................ 58 83 56 79 / 10 10 5 20
SANTA FE AIRPORT................ 56 86 55 83 / 10 5 0 10
ALBUQUERQUE FOOTHILLS........... 62 86 61 83 / 20 0 5 20
ALBUQUERQUE HEIGHTS............. 64 88 63 85 / 20 0 0 10
ALBUQUERQUE VALLEY.............. 59 90 62 87 / 20 0 0 10
ALBUQUERQUE WEST MESA........... 60 89 61 85 / 20 0 0 10
LOS LUNAS....................... 59 91 60 88 / 20 0 5 10
RIO RANCHO...................... 62 90 60 87 / 20 0 0 10
SOCORRO......................... 63 88 61 88 / 30 5 10 20
SANDIA PARK/CEDAR CREST......... 57 82 56 79 / 20 5 10 20
TIJERAS......................... 59 85 57 81 / 20 5 10 20
MORIARTY/ESTANCIA............... 51 85 53 81 / 10 5 10 30
CLINES CORNERS.................. 56 82 54 77 / 30 10 10 40
GRAN QUIVIRA.................... 58 83 57 80 / 40 10 10 40
CARRIZOZO....................... 62 88 60 84 / 40 20 20 40
RUIDOSO......................... 58 79 57 75 / 40 30 20 50
CAPULIN......................... 54 79 53 77 / 10 20 20 10
RATON........................... 52 85 51 82 / 10 20 20 10
SPRINGER........................ 53 85 53 81 / 10 20 20 10
LAS VEGAS....................... 53 81 51 77 / 20 20 20 30
CLAYTON......................... 63 85 59 82 / 10 20 20 10
ROY............................. 59 83 56 79 / 10 20 20 10
CONCHAS......................... 66 91 63 87 / 20 10 20 10
SANTA ROSA...................... 65 90 62 85 / 20 10 20 30
TUCUMCARI....................... 66 93 63 87 / 30 20 20 10
CLOVIS.......................... 64 91 63 84 / 30 20 30 20
PORTALES........................ 65 90 63 83 / 30 20 30 30
FORT SUMNER..................... 66 91 64 84 / 30 10 20 20
ROSWELL......................... 68 94 67 88 / 30 10 20 30
PICACHO......................... 62 90 62 83 / 40 20 20 40
ELK............................. 61 81 60 77 / 40 20 20 40
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
34
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1139 PM MDT SUN SEP 6 2015
.AVIATION...
06Z TAF CYCLE
SUBTROPICAL MOISTURE WILL SURGE NORTHWARD INTO NM OVERNIGHT INTO MONDAY.
EXPECT A SIGNIFICANT UPSWING IN SHOWER AND THUNDERSTORM ACTIVITY
BEGINNING LATE MORNING MONDAY AND CONTINUING THROUGH THE AFTERNOON
AND EVENING. NW PLATEAU INCLUDING KFMN THE LEAST LIKELY AREA TO
EXPERIENCE CONVECTION. MTS OCCASIONALLY OBSCD IN MVFR CIGS/VSBYS
WITH THE STRONGER STORMS MONDAY AFTERNOON/EVENING. SFC WND GUSTS
TO 40KT POSSIBLE WITH THE STRONGER STORMS.
33
&&
.PREV DISCUSSION...318 PM MDT SUN SEP 6 2015...
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS WILL CONTINUE TO FAVOR AREAS SOUTH OF
I-40 THIS EVENING...BUT STORMS MAY EXPAND FARTHER NORTHWARD ON
MONDAY AFTERNOON. DRIER AIR WILL MOVE INTO THE STATE FROM THE
NORTHWEST ON TUESDAY AND WEDNESDAY...LIMITING STORMS ACROSS THE
NORTHWEST...BUT STORMS ACROSS THE EAST REMAIN POSSIBLE AS A BACK
DOOR COLD FRONT SLIDES SOUTHWARD. TEMPERATURES WILL RUN NEAR TO A
FEW DEGREES ABOVE NORMAL THROUGH AT LEAST THE MIDDLE OF THE WEEK.
FORECAST CONFIDENCE REMAINS LOW ESPECIALLY BEYOND MID WEEK AS
MODELS CONTINUE TO FLIP FLOP ON TIMING AND STRENGTH OF ANOTHER
BACK DOOR COLD FRONT.
&&
.DISCUSSION...
FORECAST CONFIDENCE FOR THE NEXT 7 DAYS IS QUITE LOW DUE TO MODEL
INCONSISTENCIES. HENCE...EXPECT CHANGES FROM THE FOLLOWING.
GENERALLY...THE UPPER HIGH THAT IS CENTERED OVER WEST TEXAS TODAY
WILL SLOWLY SHIFT SOUTH OF NM THROUGH TUESDAY...BEFORE ELONGATING
FROM NW TO SE ACROSS SOUTHERN AZ INTO OLD MEXICO. MEANWHILE...
TROPICAL STORM LINDA HAS FORMED SOUTH OF THE BAJA AND IS FORECAST
TO MOVE NW THRU THIS TIME PERIOD. IT DOES NOT APPEAR AT THIS TIME
THAT NM WILL BENEFIT FROM TS LINDAS MOISTURE...AS THE UPPER HIGH
WILL BE BLOCKING IT FROM REACHING US.
AS FOR THE DETAILS...THAT IS WHERE IT GETS MURKY. FOR
TONIGHT...THE HRRR SEEMS TO HAVE A PRETTY GOOD HANDLE ON CURRENT
CONVECTION. THUS...EXPECT THE STORMS ALONG THE SACS TO CONTINUE TO
MOVE NEWD THIS EVENING...AS WELL AS ALONG A WEAK CONVERGENCE ZONE
ACROSS THE EASTERN PLAINS. THE HRRR ALSO DEPICTS AN UPSWING IN
ACTIVITY AFTER MIDNIGHT TONIGHT ACROSS THE SW AND SC AREAS AS A
WEAK DISTURBANCE MOVES UP IN SSW FLOW. OTHER MODELS ARE NOT
TERRIBLY ENTHUSIASTIC ABOUT THIS FEATURE DURING THE OVERNIGHT
PERIOD...BUT IT MAY BE AT LEAST IN PART A REASON WHY THE NAM IS
BREAKING OUT MUCH MORE PRECIPITATION ON MONDAY THAN OTHER
MODELS...SPECIFICALLY ACROSS THE EAST AND NORTH. THE DEGREE OF
DRYING FOR MONDAY DEPICTED BY ANY MODEL ACROSS THE NORTH IS NOT
NEARLY AS STRONG AS IT WAS 24 OR 48 HOURS AGO DESPITE THE MORE
WESTERLY FLOW ALOFT. SO STANDS TO REASON THAT MONDAY WILL BE MORE
ACTIVE THAN TODAY...AND ALSO THAT THE NAM MAY BE ONTO SOMETHING.
HOWEVER...THE AMOUNT OF MID AND HIGH CLOUDS THAT MAY BE AROUND DUE
TO OVERNIGHT CONVECTION...IF THE HRRR IS RIGHT...MAY DIMINISH SOME
OF THE POTENTIAL INSTABILITY.
THE DRY AIR DOES APPEAR TO COME INTO AT LEAST THE NW AND PERHAPS
NC AREAS ON TUESDAY... WHICH SHOULD LIMIT CONVECTION THERE. THE
BACK DOOR FRONT THAT IS EXPECTED TO COME INTO THE NE LOOKS
STRONGER... AND MODELS ARE EVEN SHOWING AN INCREASE IN DEWPOINTS
ON TUESDAY AND TUESDAY NIGHT BEHIND THE FRONT. THEREFORE...HAVE
BUMPED UP POPS SLIGHTLY ACROSS THE SANGRES TO ACCOUNT FOR THE
MOIST UPSLOPE FLOW. THE FRONT DOES LOOK TO PUSH FURTHER SOUTH AND
WEST THAN WHAT MODELS SHOWED YESTERDAY...PERHAPS EVEN OOZING THRU
THE GAPS OF THE CENTRAL MTN CHAIN WED MORNING. WOULD EXPECT THE
CENTRAL MTN CHAIN TO HAVE A FAIR AMOUNT OF ACTIVITY ON WEDNESDAY
AFTERNOON WITH CONTINUED UPSLOPE FLOW AS THE WINDS SLOWLY VEER
AROUND TO THE EAST AND SOUTHEAST ACROSS THE PLAINS...BUT MODELS DO
NOT SHOW A CLEAR SIGNAL OF THAT. THIS IS LIKELY BECOMES OF THE
DRIER MID LEVEL AIR CONTINUING TO MOVE INTO THE NW HALF OF NM.
THUS...THE LOW LEVEL MOISTURE AND UPSLOPE FLOW WILL LIKELY HAVE A
FIGHT WITH THE STABILITY AT MID LEVELS.
THE STRONG FRONT THAT WAS SUPPOSED TO ARRIVE THURSDAY NIGHT AND
FRIDAY...WELL...APPARENTLY THE MODELS HAVE DECIDED THAT IS NOT
GOING TO HAPPEN. AFTER SHOWING THAT SCENARIO FOR SEVERAL MODEL
RUNS...BOTH THE LATEST EC AND GFS SHOW ONLY A WEAK WIND SHIFT
ACROSS THE NE. THUS POP CHANCES DURING THIS PERIOD AND THRU
SATURDAY HAVE BEEN TRIMMED CONSIDERABLY. BUT AS STATED AT THE
BEGINNING...CONFIDENCE IS QUITE LOW AND MODELS MAY YO-YO BACK
TOMORROW.
34
&&
.FIRE WEATHER...
ANOTHER RELATIVELY SLOW DAY FOR CONVECTION SO FAR. SOME DRIER AIR
HAS PUSHED INTO THE WEST AND CENTRAL IN THE MID LEVELS ALLOWING LOW
LEVEL MOISTURE TO MIX OUT. SHORT TERM MODELS STILL INDICATE LOCALES
SOUTH OF INTERSTATE 40 AND ALONG/EAST OF THE PECOS WILL HAVE THE
BEST CHANCES FOR WETTING RAIN TONIGHT. IN GENERAL...CELL MOVEMENT
WILL AGAIN BE TO THE NORTHEAST FOR THE REST OF THIS AFTERNOON AND
TONIGHT.
MONDAY FEATURES SOMEWHAT MORE WESTERLY WINDS...AND WITH HIGHER POPS
ALONG AND SOUTH OF INTERSTATE 40 AS THE TAP OF MOISTURE IS NOT
TOTALLY CUT OFF. OTHERWISE...CONFIDENCE IN THE TIMING OF FRONTS FOR
THIS WEEK IS AT AN ALL TIME LOW. THE STRONGER BOUNDARY...AND PUSH OF
LOW LEVEL MOISTURE WESTWARD...COULD NOW BE TUESDAY/WEDNESDAY AS THE
GFS CONTINUES TO DOWNPLAY THE FRIDAY/SATURDAY BOUNDARY. SO...THERE
WILL LIKELY BE A BOUNDARY OR MORE THIS WEEK IMPACTING ERN NM...AND
ACCOMPANIED BY SLOSHING OF LOW LEVEL MOISTURE WWD TO THE CENTRAL MT
CHAIN AND EVEN INTO THE RGV...BUT WHEN IT WILL HAPPEN THE MODELS
CAN/T...SO FAR...SEEM TO PREDICT CONSISTENTLY. THIS WILL IMPACT
CHANCES FOR WETTING RAIN TO AT LEAST SOME EXTENT...AND DAY TO DAY
CHANGES IN RH AND TEMPERATURES. CURRENT TRENDS THOUGH ARE FOR HIGHER
POPS TO SHIFT TO THE CENTRAL MT CHAIN/SOUTHEAST HALF OF THE FORECAST
AREA BY MIDWEEK...THEN DIMINISH OVERALL NEXT WEEKEND.
WHAT DOES APPEAR LESS VARIABLE IS ADDITIONAL DRYING OF WRN NM FROM
THE CONTDVD TO THE AZ BORDER. MID TO LATE WEEK...HIGH HAINES IS
FORECAST OVER THIS REGION AND LATE DAY DEW POINTS FALL INTO THE 30S
WITH EVEN SOME 20S THE FARTHER NORTH AND WEST YOU GO. CONSEQUENTLY
OVERNIGHT RH RECOVERIES LOOK TO BE FAIR TO EVEN POOR NORTHWEST BY
THURSDAY/FRIDAY NIGHT WHILE MIN RH VALUES FALL BELOW 15 PERCENT.
FORECAST VENT RATES MOSTLY GOOD TO EXCELLENT MONDAY/TUESDAY THEN
DECREASE SOME WEDNESDAY/THURSDAY WITH AREAS OF FAIR TO POOR CENTRAL
AND NORTH. FORECAST HIGHS WILL RUN WITHIN A FEW DEGREES OF AVERAGE
THRU WEDNESDAY/THURSDAY.
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
11
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
1000 PM EDT TUE SEP 8 2015
.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFFSHORE THROUGH MIDWEEK AS WEAK LOW
PRESSURE DEVELOPS TO THE WEST. A STRONG COLD FRONT WILL APPROACH
FROM THE WEST LATE IN THE WEEK AND CROSS THE AREA BY LATE THIS
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AS OF 10 PM TUESDAY...PRECIPITATION HAS DISSIPATED ACROSS OUR CWA
AND HAVE REMOVED ALL POPS FROM THE FORECAST OVERNIGHT. LATEST RUN
OF THE 3KM HRRR AND RUC MODELS INDICATE NO ADDITIONAL
PRECIPITATION OVER LAND AREAS OVERNIGHT. WITH HIGH LOW-LEVEL
MOISTURE AND LIGHT WINDS...FOG IS A GOOD BET OVERNIGHT. NO
CHANGES TO FORECAST TEMPERATURES WITH LOWS AROUND 70 INLAND TO MID
70S BEACHES.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
AS OF 2 PM TUE...WEAK UPPER RIDGING OVER THE BAHAMAS/FLORIDA WITH
LONG WAVE TROUGHING ACROSS THE UPPER PLAINS/MIDWEST WILL RESULT IN
SOUTHWESTERLY FLOW ALOFT. S TO SW SFC SFC WINDS WILL RESULT IN
WARM AND MUGGY CONDITIONS ALONG WITH ISOLATED TO SCATTERED DIURNAL
SHOWERS AND THUNDERSTORMS...BEST CHANCES ALONG THE SEA BREEZE.
COASTAL AREAS SHOULD REMAIN MOSTLY DRY AND THE SEVERE THREAT IS
LOW DUE TO WEAK UPPER LEVEL SUPPORT. HIGHS WILL RANGE FROM NEAR 90
INLAND TO MID 80S BEACHES.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
AS OF 315 PM TUESDAY...SUMMERLIKE PATTERN THROUGH THE FIRST PART
OF THE LONG TERM PERIOD WITH SCATTERED SHOWERS AND THUNDERSTORMS,
THEN A BETTER CHANCE OF PRECIP LATE IN THE WEEK, FOLLOWED BY A
POSSIBLE STRONG COLD FRONTAL PASSAGE AND COOLER/DRIER CONDITIONS
BY LATE WEEKEND/EARLY NEXT WEEK.
THURSDAY THROUGH FRIDAY...LARGE SCALE TROUGH ACROSS THE NORTHERN
TIER OF THE CONUS WILL MIGRATE EASTWARD DURING THE PERIOD, WHILE
UPR RIDGE AMPLIFIES ACROSS THE INTERMOUNTAIN WEST. THIS WILL
INDUCE STRONG DIGGING SHORTWAVE TROUGH ACROSS THE EASTERN US/OHIO
VALLEY BY THE WEEKEND. AHEAD OF THIS SYSTEM IN RESPONSE...DEEP
LAYER SWRLY FLOW WILL PUMP IN VERY WARM AND HUMID CONDITIONS. WEAK
SURFACE FRONT WILL SLOWLY MOVE THROUGH THE GREAT LAKES AREA,
SOUTHEAST INTO THE WESTERN SLOPES OF THE APPALACHIAN MOUNTAINS ON
THURSDAY. SLIGHTLY BETTER CHANCES FOR ORGANIZED PRECIP AS
MOISTURE CONVERGENCE INCREASES OVER THE SOUTHEAST CONUS WITH
NEARLY UNIDIRECTIONAL SW FLOW OVER EASTERN NC. MAINTAINED HIGH
CHANCE POPS THURSDAY THROUGH FRIDAY FOR INLAND ZONES DUE TO HIGH
PWATS AND PIECES OF SHORTWAVE ENERGY ROTATING AROUND STRONGER
SHORTWAVE TO THE NORTH AND WEST. THE BULK OF UPPER LEVEL SUPPORT
WILL REMAIN NORTH OF THE REGION SO SEVERE THREAT WILL BE MINIMAL.
CONDITIONS WILL CONTINUE TO BE VERY MUGGY AND ABOVE CLIMO WITH
HIGHS 85-90 AND LOWS IN THE 70S.
THIS WEEKEND...THERE ARE STILL SOME DIFFERENCES AMONGST MODEL
SUITE IN REGARDS TO EVOLUTION OF THE DIGGING STRONG SHORTWAVE
THIS WEEKEND. HAVE CONTINUED TO FOLLOW MORE CLOSELY TO WPC/ECMWF
SOLN. A LOOK AT THE ENSEMBLE MEAN HEIGHTS INDICATE THE NCEP/ECM
ENSEMBLE MEAN ALONG WITH ECMWF/GEM GLOBAL HAVE FAIRLY UNANIMOUS
SUPPORT WITH HANDLING UP UPR LOW/SHORTWAVE POSITIONING ACROSS THE
OHIO VALLEY...WHILE DETERMINISTIC GFS STILL A BIT OF AN OUTLIER. THIS
WILL KEEP AREA IN THE WARM SECTOR WITH GOOD CHANCES OF SHOWERS AND
STORMS ON SATURDAY. WILL RAISE POPS A BIT...INTO THE 40-50 PERCENT
RANGE. INCREASING MID AND UPPER SW FLOW COULD BRING A THREAT FOR
SEVERE STORMS AS DEEP LAYER SHEAR INCREASES...WITH SEVERE THREAT
BEING DEPENDENT ON AMOUNT OF AVAILABLE INSTABILITY. FOR SUNDAY,
MORE QUESTIONABLE ON HOW QUICKLY SYSTEM EXITS THE EASTERN CONUS
WITH A FASTER FRONTAL PASSAGE SOLUTION BRINGING DRIER AND COOLER
CONDITIONS AND A SLOWER SCENARIO KEEPING SHOWER CHANCES THROUGH
THE DAY. FOR NOW WILL MAINTAIN THE 30 POPS.
MONDAY AND TUESDAY...MONDAY SHOULD BRING A RETURN TO COOLER AND
MUCH DRIER CONDITIONS WITH HIGHS IN THE 80-85 RANGE AND LOWS 60-65
INLAND TO 65-70 BEACHES. TD`S WILL BE DOWN INTO THE 50S BRINGING
FIRST EARLY TOUCH OF FALL TO THE REGION UNDER MOSTLY SUNNY SKIES.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
SHORT TERM /THROUGH 00Z THURSDAY/...
AS OF 650 PM TUESDAY...CONDITIONS BECOMING MORE FAVORABLE FOR
DENSE FOG/STRATUS FORMATION LATER TONIGHT. HIGH BOUNDARY LAYER
MOISTURE COUPLED WITH NEARLY CALM WINDS WILL LEAD TO PERIODS OF
IFR AND PERHAPS LIFR FOG OVERNIGHT ALONG WITH STRATUS. GOOD
AGREEMENT IN THE NUMERICAL GUIDANCE AND LOCAL FOG TOOLS SHOWING A
HIGH PROBABILITY OF WIDESPREAD LOWER CEILINGS AND VSBYS.
CONDITIONS IMPROVE BY MID-MORNING ON WEDNESDAY WITH JUST A FEW
WIDELY SCATTERED TSTMS IN THE AFTERNOON.
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/
AS OF 315 PM TUESDAY...GENERALLY VFR THROUGH THE PERIOD, THOUGH
OCCASIONAL FOG POSSIBLE EACH NIGHT/EARLY MORNING DUE TO CALM WINDS
AND HIGH BOUNDARY LAYER MOISTURE. TEMPO RESTRICTIONS POSSIBLE EACH
AFTERNOON DUE TO SCATTERED SHOWERS/THUNDERSTORMS. BETTER CHANCE
FOR MORE WIDESPREAD SHOWERS/THUNDERSTORMS LATE WEEK INTO FIRST
PART OF THE WEEKEND AHEAD OF A STRONG COLD FRONT. WINDS WILL INC
OUT OF THE SW ON THUR AND BECOME GUSTY 12-16 KT.
&&
.MARINE...
SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
AS OF 10 PM TUESDAY...MINOR ADJUSTMENTS TO WIND DIRECTION AS WINDS
ARE GENERALLY SE/S AT SPEEDS OF 10 KNOTS OR LESS WITH SEAS
GENERALLY 2 TO 3 FEET WITH SOME LONGER PERIOD SWELL ENERGY. NO
CHANGES TO THIS ARE EXPECTED OVERNIGHT. WINDS VEER TO MORE SW BY
EARLY WEDNESDAY AS AXIS OF HIGH PRESSURE RIDGE SHIFTS OFFSHORE.
SEAS CONTINUE AT 2 TO 3 FEET FOR WEDNESDAY.
LONG TERM /WED NIGHT THROUGH SUNDAY/
AS OF 315 PM TUESDAY...GENERALLY GOOD BOATING CONDITIONS CONTINUE
THROUGH WEDNESDAY NIGHT, THEN A TIGHTENING SOUTHWESTERLY PRESSURE
GRADIENT WILL CREATE MARGINAL CONDITIONS BY THURSDAY THROUGH THE
WEEKEND.
WINDS WILL BE SW 5-15 KT WEDNESDAY NIGHT THROUGH EARLY THURSDAY,
THEN INCREASE TO 10-20 KT LATER THURSDAY, HIGHEST ON THE OUTER
PORTIONS OF THE COASTAL WATERS. SEAS WILL GENERALLY BE 3 FEET OR
LESS THROUGH EARLY THURSDAY, THEN BUILD 3-5 FT THURSDAY INTO
FRIDAY IN RESPONSE TO STRENGTHENING SOUTHWESTERLY WINDS. STRONG
COLD FRONT WILL APPROACH BY LATE WEEKEND, THOUGH FORECAST
CONFIDENCE STILL RELATIVELY LOW AT THIS TIME DUE TO DISAGREEMENT
AMONGST GUIDANCE IN THE FAR EXTENDED PERIOD. CONTINUED AROUND A
FOOT HIGHER THAN 12Z WAVEWATCH GUIDANCE AS ITS GFS-BASED WINDS
WERE LOWER THAN FCST 15-20 KT SUSTAINED WINDS. CONDITIONS COULD
REACH MARGINAL SCA CRITERIA WITH 6 FOOT SEAS FOR A TIME LATE
SATURDAY INTO EARLY SUNDAY AHEAD OF THE STRONG COLD FRONT.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JAC
NEAR TERM...CTC
SHORT TERM...JAC
LONG TERM...DAG/TL
AVIATION...CTC/TL
MARINE...CTC/TL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
900 PM EDT TUE SEP 8 2015
.SYNOPSIS...A COLD FRONT WILL APPROACH FROM THE NORTHWEST TONIGHT...
THEN WEAKEN TO A TROUGH BEFORE STALLING OVER THE AREA WEDNESDAY
THROUGH FRIDAY. A STRONGER COLD FRONT AND UPPER LEVEL LOW WILL
APPROACH FROM THE NORTHWEST FRIDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 900 PM TUESDAY...
WITH THE LOSS OF HEATING AND GROWTH OF SURFACE-BASED CINH... AND IN
THE ABSENCE OF ANY OTHER DYNAMIC OR KINEMATIC FORCING FOR ASCENT...
WE`VE SEEN A RAPID DECREASE IN COVERAGE OF TROPICAL-TYPE SHOWERS
OVER CENTRAL NC IN THE LAST HOUR. BUT WITH PW VALUES STILL WELL
ABOVE NORMAL AROUND 2.0 INCHES AND WEAK BUT PERSISTENT LOW LEVEL
MOISTURE TRANSPORT... IT MAY BE A LITTLE WHILE LONGER BEFORE THE
SHOWERS ARE COMPLETELY GONE... SO WILL LEAVE IN A MENTION OF
ISOLATED SHOWERS FOR ANOTHER FEW HOURS. THE DIMINISHING OF
CONVECTIVE CLOUDINESS HAS RESULTED IN PARTIAL OR TOTAL CLEARING OVER
MUCH OF CENTRAL NC... BUT SKIES SHOULD TREND BACK TOWARD MOSTLY
CLOUDY WITH THE ARRIVAL OF MID AND HIGH CLOUDS FROM THE SOUTH... A
REFLECTION OF A STEADY MOISTURE STREAM AROUND THE EAST/NORTH SIDES
OF THE UPPER LOW SPINNING JUST SOUTH OF LA... AND WITH THE PROBABLE
DEVELOPMENT OF STRATUS OVERNIGHT AS INDICATED BY THE LATEST HRRR AND
CANADIAN MODELS. BASED ON THE LATEST HIGH RES GUIDANCE INCLUDING THE
HRRR/LAMP/LOCAL WRF... EXPECT LOWS AROUND 70 TO THE LOWER 70S. -GIH
&&
.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
AS OF 305 PM TUESDAY...
PRE-FRONTAL TROUGH DEVELOPS IN THE LEE OF THE MOUNTAINS ON WEDNESDAY
AS SHORTWAVE TROUGH ATTENDANT SFC COLD FRONT TRACK EAST INTO OHIO
AND MS VALLEY. ASIDE FROM THE PRE-FRONTAL TROUGH IN THE WEST AND
SEABREEZE BOUNDARY IN THE EAST...WEAK FORCING VIA STRONG DIABATIC
HEATING WILL BE THE PRIMARY LIFT/FORCING MECHANISM. WITH SEASONABLY
HIGHS PW`S IN THE 1.75-2.0" RANGE...SURFACE HEATING SHOULD LEAD TO
AT LEAST ISOLATED TO SCATTERED THUNDERSTORMS. HIGHS IN THE MID TO
UPPER 80S. LOWS IN THE UPPER 60S TO LOWER 70S.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS OF 305 PM TUESDAY...
A LONG WAVE TROUGH WILL DIG INTO THE MISSISSIPPI RIVER VALLEY TO
START THE PERIOD AND WILL PROPEL A FRONT TOWARDS THE REGION BY
THURSDAY. MOISTURE WILL INCREASE EVEN MORE AS DEEP SOUTHWESTERLY
FLOW SETS UP OVER THE REGION. THIS...ALONG WITH INCREASING
FORCING...WILL LEAD TO GOOD CHANCES OF CONVECTION ON THURSDAY.
TROUGHING IS THEN PROGGED TO PERSIST OVER THE EASTERN CONUS THROUGH
MUCH OF NEXT WEEKEND. ANOTHER SHORTWAVE TROUGH IS THEN PROGGED TO
DROP INTO THE OHIO VALLEY OVER THE WEEKEND AND MODELS HAVE COME INTO
BETTER AGREEMENT WITH DEVELOPING A CUT OFF LOW BY SUNDAY. (HOWEVER
THE ARE STILL INCONSISTENCIES WITH REGARDS TO THE EVOLUTION AND
EVENTUAL TRACK OF THIS UPPER LOW). ANOTHER FRONT WILL ACCOMPANY THIS
TROUGH...BUT THE TIMING OF THIS FRONTAL PASSAGE IS UP IN THE AIR AT
THIS POINT GIVEN THE UNCERTAINTY OF THE UPPER PATTERN. THEREFORE...
WILL KEEP ELEVATED PRECIP CHANCES IN THE FORECAST THROUGH THE END OF
NEXT WEEKEND (AFTER A BRIEF LULL ON FRIDAY BETWEEN THE TWO SYSTEMS).
BY MONDAY...MODELS FINALLY SHOW THE TROUGH PUSHING TO THE EAST OF
THE AREA...TAKING PRECIP CHANCES WITH IT (ALTHOUGH THIS IS SUBJECT
TO CHANGE GIVEN THE LOW CONFIDENCE IN THE MODELS AND IN FACT THE
ECMWF IS MOSTLY DRY BY SUNDAY). GIVEN THE EXPECTED CLOUD
COVER/PRECIP THROUGH MUCH OF THE PERIOD...TEMPS SHOULD REMAIN NEAR
TO BELOW NORMAL...EXCEPT ON THURSDAY AHEAD OF THE FRONT WHEN MID TO
UPPER 80S ARE EXPECTED.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
AS OF 800 PM TUESDAY...
24 HOUR TAF PERIOD: A COUPLE OF STRAY SHOWERS REMAINING NEAR KFAY
BUT OTHERWISE...THE REST OF THE TERMINALS LOOK TO REMAIN DRY FOR THE
REMAINDER OF THE EVENING. THE FORECAST PROBLEM OVERNIGHT WILL BE FOG
AND LOW STRATUS AND RELATIVE HUMIDITY CROSS SECTIONS...SREF
PROBABILITIES AND FORECAST SOUNDINGS ALL SHOW THE POSSIBILITY OF
THAT HAPPENING AS DAYBREAK APPROACHES. THEREFORE HAVE INCLUDED THE
POSSIBILITY IN THE TAFS AT ALL SITES AFTER 9Z BUT THE SEVERITY OF IT
REMAINS UNCERTAIN. FOR NOW HAVE MVFR CONDITIONS IN PLACE BUT SOME
PERIODIC IFR/LIFR CONDITIONS CANT BE RULED OUT.
EXPECT SCATTERED SHOWERS AND THUNDERSTORMS TO BEGIN POPPING UP AFTER
18Z ACROSS THE AREA WITH ALL SITES HAVING A GOOD CHANCE OF SEEING
SOME VICINITY SHOWERS AND THUNDERSTORMS. HAVE INCLUDED AS A PROB30
GROUP AT THIS TIME.
LONG TERM: A STALLING FRONTAL SYSTEM MOVING INTO THE AREA AND THEN
AN UPPER LEVEL LOW WILL KEEP CONDITIONS UNSETTLED FOR THE END OF THE
WEEK THROUGH AT LEAST SATURDAY BEFORE A COOLER AND DRIER AIRMASS
MOVES IN ON SUNDAY AND INTO EARLY NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...CBL
LONG TERM...KRD
AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
254 PM EDT MON SEP 7 2015
.SYNOPSIS...
A LATE SUMMERTIME PATTERN OF WARM DAYS WITH SCATTERED AFTERNOON
AND EVENING THUNDERSTORMS WILL CONTINUE FOR THE NEXT FEW DAYS. THE
NEXT SIGNIFICANT WEATHER SYSTEM TO AFFECT THE AREA WILL BE A COLD
FRONT THAT MOVES SLOWLY TOWARD THE AREA THIS WEEKEND AND MAY SLIP
OFFSHORE EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM MONDAY...PRECIPITABLE WATER TRENDING UPWARD INLAND PER
LATEST SATELLITE-DERIVED BLENDED PWAT SCANS...HAVING NEARLY ERASED
THE DRY COLUMN FOOTHOLD OVER INTERIOR NE SC AND SE NC. PRESENTLY
LAND CONVECTION HAS SPROUTED AND UNDERWAY...ASSISTED BY A MYRIAD OF
UPDRAFT STARTERS INCLUDING OUTFLOW BOUNDARIES...DIFFERENTIAL HEATING
AND LOW-LEVEL CONVERGENCE ALONG A WEAK SEA BREEZE BOUNDARY. RECENT
KLTX VWP DATA SHOWS EAST WINDS IN THE LOWEST 8KFT WITH SE-S FLOW
THROUGH THE MIDDLE AND UPPER LEVELS. IT IS EXPECTED THAT DIURNAL
COOLING THROUGH EVENING WILL REMOVE SOME OF THE STEAM FROM CELLS AND
A DECREASE IN AREAL COVERAGE INLAND. A TRANSITION TO INCREASED
MARINE CONVECTION TONIGHT AS BUOYANCY INCREASES OVER THE WATERS
ESPECIALLY INTO VERY EARLY TUESDAY. AS A RESULT MENTIONABLE POPS ARE
RETAINED ALONG AND NEAR THE COAST OVERNIGHT. 70-75 MOST LOCATIONS
FOR MINIMUM TEMPERATURES TUESDAY DAYBREAK 76-79 BEACHES. PATCHES OF
MIST AND FOG CANNOT BE RULED OUT INLAND UNDER PARTIALLY CLEAR SKIES
INTO VERY EARLY TUESDAY.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 PM MONDAY...LOW PRESSURE WILL CONTINUE TO RETROGRADE AS RIDGING
BUILDS IN FROM THE SOUTHEAST AT LEAST THROUGH EARLY WEDNESDAY. AFTER
THIS A SHORTWAVE TROUGH MOVES INTO THE TENNESSEE VALLEY WHICH LOWERS
HEIGHTS ONCE AGAIN. AT THE SURFACE A WEAK SOUTHEAST FLOW WILL BE IN
PLACE TUESDAY. A BETTER DEFINED PIEDMONT TROUGH WILL DEVELOP
WEDNESDAY AFTERNOON. POPS WILL BE MORE RELEGATED TO A SUMMERTIME
PATTERN WITH THE LOSS OF THE UPPER LEVEL LOW INFLUENCES. SLIGHT TO
LOW CHANCE POPS ARE IN PLACE THROUGHOUT THE PERIOD WITH THE HIGHEST
VALUES MOSTLY IN THE AFTERNOONS AND EVENINGS. CONTINUED TO LEAN MORE
IN THE DIRECTION OF THE GFS/MAV NUMBERS WHICH ARE VERIFYING MUCH
BETTER WITH MORNING LOWS VS THE OTHERS.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 300 PM MONDAY...INLAND SURFACE TROUGHINESS BECOMES ESTABLISHED
ON THURSDAY AND A SOUTHWESTERLY RESULTANT SEABREEZE EXPECTED.
LOOKING FOR A SLIGHTLY WARM AFTERNOON WITH POSSIBLY DECENT COVERAGE
OF CONVECTION. COLD FRONT MOVES IN ON FRIDAY AND LIKELY
DECELERATING. RAIN CHANCES WILL TEND TO INCREASE WITH THE APPROACH
OF THIS BOUNDARY AND FUTURE FORECAST ITERATIONS MAY BE ABLE TO FINE
TUNE WHICH AREAS IF ANY DESERVE HIGHER POPS, HINGING MOST ON THE
SPEED OF THE FRONT. THE WEEKEND IS REALLY SHAPING UP TO BE UNSETTLED
WITH ANOTHER FRONT MOVING INTO THE SOUTHEASTERN U.S. THIS SECONDARY
BOUNDARY WILL BE BEING DRIVING BY AN IMPRESSIVE SYSTEM ALOFT THAT
MAY NOT ONLY YIELD HIGHER RAIN CHANCES BUT PERHAPS SOME STRONGER
THUNDERSTORMS.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
AS OF 18Z...BIT OF A TRICKY AFTERNOON WITH REGARDS TO CONVECTION.
THE HRRR IS NOT VERY ENTHUSED...WITH MAINLY ISOLATED ACTIVITY THROUGH
THE AFTERNOON. GIVEN THAT WE ARE AROUND OUR CONVECTIVE TEMP...AND
THE FACT THAT THE NAM HAS HIGH POPS...WILL KEEP CONVECTION FAIRLY
PREVALENT ALONG THE COAST...PRESSING INLAND AS THE AFTERNOON WEARS
ON. NOT SURE IF THE SHOWERS WILL MAKE IT TO THE INLAND TERMINALS
SO WILL STICK WITH VCSH. THE NAM IS THE MOST AGGRESSIVE...KEEPING
HIGH POPS ALL THE WAY TO 06Z. THINK THIS IS OVERDONE AND WILL
DISSIPATE MOST OF THE CONVECTION BY 02-03Z. STRATUS WILL BE REINTRODUCED
AFTER MIDNIGHT THROUGH MOST OF THE MORNING HOURS. LOOK FOR THE WINDS
TO SHIFT TO SOUTHERLY AS HIGH PRESSURE MOVES OFFSHORE TUESDAY.
EXTENDED OUTLOOK...PREDOMINANTLY VFR WITH BRIEF MVFR AND POSSIBLY
IFR...IN MORNING FOG...AND ISOLATED/SCATTERED AFTERNOON EARLY
EVENING SHOWERS AND THUNDERSTORMS THROUGH THE EXTENDED.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM MONDAY...WINDS TO VEER TO SE-S AND EASE OVERNIGHT AS HIGH
PRESSURE ALONG THE NC/VA INLAND BORDER WEAKENS CONSIDERABLY AND THE
SYNOPTIC FLOW BECOMES CONTROLLED BY LARGER BERMUDA HIGH PRESSURE
FARTHER OFFSHORE. WINDSPEEDS 10 KT OR LESS AFTER MIDNIGHT TONIGHT
INTO EARLY TUESDAY SE-S. MARINERS SHOULD CONSIDER OBTAINING A RADAR
UPDATE BEFORE VENTURING OUT AS SEVERAL STRONG TSTMS MAY BE CRUISING
THE WATERS...MOVING SLOWLY TO THE NW-N TONIGHT AND EARLY TUESDAY.
OUTSIDE OF TSTMS SEAS WILL SETTLE TO 2-3 TONIGHT COMPRISED OF ESE
WAVES 1-2 FT EVERY 9 AND 12 SECONDS...AND A LIGHT SE CHOP.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 PM MONDAY...SOUTHEAST WINDS AROUND TEN KNOTS SHOULD COVER
THE WATERS FOR TUESDAY INTO EARLY WEDNESDAY. A MORE PRONOUNCED
PIEDMONT TROUGH WILL INCREASE WIND SPEEDS SLIGHTLY FOR WEDNESDAY
INTO A 10-15 KNOT RANGE. WINDS VEER TO THE SOUTHWEST LATE AS A FRONT
IN THE TENNESSEE VALLEY EDGES CLOSER. SIGNIFICANT SEAS WILL BE A MIX
OF WEAK WIND WAVES AND A VERY MODEST SWELL COMPONANT TEAMING UP TO
BRING 1-3 FOOTERS. A FEW FOUR FOOTERS COULD ENTER THE MIX LATE.
LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 300 PM MONDAY...A DEVELOPING PIEDMONT TROUGH WILL BRING AN
INCREASED SOUTHWESTERLY FLOW ON THURSDAY AND THE INTRODUCTION OF
SOME 4 FT SEAS ALONG THE OUTER PORTIONS OF THE FORECAST ZONES. THE
APPROACH OF A COLD FRONT FROM THE NORTHWEST WILL EASE THE GRADIENT
EVEN SO SLIGHTLY PERHAPS EASING THE 4 FT SEAS OUT OF THE FORECAST.
THIS BOUNDARY STALLS SOMEWHERE JUST TO OUR WEST WHICH WILL FURTHER
ABATE THE GRADIENT IN ADDITION TO VEERING THE FLOW DIRECTION. HOW
MUCH OF THE LATTER OCCURS WILL DEPEND ON WHERE THE BOUNDARY DECIDES
TO STALL WHICH IS NOT YET CLEAR.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SHK
NEAR TERM...MJC
SHORT TERM...SHK
LONG TERM...MBB
AVIATION...MJC/DL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
128 PM EDT MON SEP 7 2015
.SYNOPSIS...
LOW PRESSURE ALOFT MOVING ACROSS THE GULF COAST STATES WILL
PRODUCE ONSHORE WINDS AND SHOWERS ACROSS THE EASTERN CAROLINAS
TODAY. LATE SUMMER CONDITIONS WILL RETURN MID-WEEK AHEAD OF A
COLD FRONT APPROACHING FROM THE NORTHWEST. THE FRONT MAY STALL
ALONG THE COAST NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 128 PM MONDAY...NO REMARKABLE CHANGES TO THE ONGOING
FORECAST. PARTIAL SUNSHINE WILL AID IN BOOSTING LOW-LEVEL
CONVECTIVE ENERGY...AND A TRANSITION TO DEVELOPING SHOWERS AND
ISOLATED TSTMS OVER LAND SHOULD PREVAIL THROUGH AFTERNOON. IT
WILL BE INTERESTING TO SEE HOW THE 3 DEGREES CELSIUS OF WARMING
AT 500 MB COMPARED TO YESTERDAY...DUE TO THE RETROGRADING COOL
POOL...WILL IMPACT CONVECTIVE BEHAVIOR TODAY. PWAT VALUES OF
1.7-2.0 INCHES WILL BE AMPLE TO RESULT IN POCKETS OF HEAVY RAIN.
OUTSIDE OF CELL-TRAINING...STORM MOTION AROUND 15 KT SHOULD LIMIT
LOCALIZED FLOODING POTENTIAL. THE PREVIOUS DISCUSSION FOLLOWS.
RETROGRESSION OF AN UPPER LOW EVIDENT IN VAPOR MOVIES ACROSS
ALABAMA HAS ALTERED THE UPPER WINDS LOCALLY. KLTX VAD WIND PROFILE
REGISTERING EAST WIND 15-25 KT FROM 1-9KFT WHILE ABOVE THIS SE
15-20 KT FLOW. THIS WILL PUSH SHALLOWER CONVECTION MORE DIRECTLY
EAST WHILE DEEPER TOWERS TRAVEL MORE TO THE NORTHWEST. WEAKENING
UPPER PORTIONS OF THE CUMULO-NIMBUS THROUGH ITS LIFE CYCLE WILL BE
SPREAD NW OF THE PRIMARY RAIN CORES...ALLOWING LIGHTER STRATIFORM
TYPE PCPN/-RA TO REACH AREAS FARTHER INLAND. RECENT AMSU AND SSM/I
PWAT LOOPS SHOW THE PRECIPITABLE WATER GRADIENT HAS FILLED IN AND
MOISTENED AREAS ALONG AND WEST OF I-95 IN ROUGHLY 43MM/1.7 INCH
VALUES...MORE THAN SUFFICIENT VAPOR FOR CONVECTIVE LONGEVITY
INLAND. FORMATION OF CONVECTION IS A GOOD BET THIS AFTERNOON AS
WELL...AS LAND HEATING RAMPS UP. OUTFLOWS AND DIFFERENTIAL HEATING
MECHANISMS WILL BOTH SUPPORT CONVECTIVE INITIATION...AND FORECAST
MAXIMUM TEMPERATURES WILL ADD A ZONE OF WEAK LOW-LEVEL CONVERGENCE
TO THE MIX ALONG THE COASTAL INTERIOR SEA BREEZE FRONT. DIURNAL
COOLING LATE IN THE DAY WILL REMOVE CONVECTIVE INTENSITY AND POP
VALUES WILL SHOW A DECLINE THROUGH EVENING...BUT AN UPTREND IN
MARINE CONVECTION INTO VERY EARLY TUESDAY POSSIBLY DELIVERING
COASTAL SHOWERS.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 AM MONDAY...UPPER TROUGH WILL CONTINUE TO RETROGRADE
WESTWARD ACROSS THE GULF COAST STATES TUESDAY...BUT IN A MUCH WEAKER
FASHION THAN EARLIER IN THE WEEK. AT THE SAME TIME...RIDGING
BLOSSOMING EAST OF FLORIDA WILL EXPAND NORTH INTO THE CAROLINAS
TUESDAY AND WEDNESDAY...WHICH WILL LEAD TO LESS UNSETTLED WEATHER
ALONG WITH WARMER TEMPERATURES BY MID WEEK. TUESDAY WILL BE THE
TRANSITION DAY AND WILL FEATURE A GOOD CHANCE FOR SHOWERS/TSTMS AS
THE SURFACE TROUGH SLOWLY ERODES AND LIFTS NORTH...BUT STILL SERVES
AS A FOCUS FOR CONVECTION IN AN UNSTABLE ENVIRONMENT WITH PWATS JUST
BELOW 2 INCHES. THIS BOUNDARY WILL NOT BE PRESENT ON WEDNESDAY...AND
INCREASING HEIGHTS ALOFT WILL INHIBIT STRONG LIFT...BUT A CONTINUED
VERY MOIST ENVIRONMENT AND ABOVE NORMAL TEMPERATURES WILL ALLOW FOR
MORE TYPICAL DIURNAL CONVECTION ALONG THE SEA BREEZE AND PIEDMONT
TROUGH. TEMPS THROUGH MID-WEEK WILL WARM EACH DAY...FROM NEAR
SEASONABLE TUESDAY...MID 80S FOR HIGHS AND AROUND 70 FOR
LOWS...TO UPPER 80S WEDNESDAY WITH MINS WED NIGHT IN THE LOW TO
MID 70S.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 300 AM MONDAY....LATE SUMMER HEAT TO RETURN FOR THE END OF THE
WEEK AS RIDGING EXPANDS ACROSS THE WESTERN ATLANTIC AND THE EAST
COAST...BUT A COLD FRONT WILL APPROACH LATE FRIDAY AND THEN LIKELY
STALL ACROSS THE REGION DURING THE UPCOMING WKND. WHILE THE AIR MASS
BEHIND THIS FEATURE IS ONLY SUBTLY DIFFERENT FROM THAT OUT AHEAD OF
IT...INCREASING CLOUDS AND CONVECTION WILL BRING A RETURN TO COOLER
TEMPERATURES WITH MORE UNSETTLED CONDITIONS SATURDAY AND SUNDAY.
TEMPS THU/FRI WILL FEATURE A LOT OF READING NEAR 90 DEGREES WITH
TYPICAL SUMMERTIME CONVECTION ACTIVITY EXPECTED. AS THE FRONT
CROSSES AND STALLS THIS WKND...TEMPS WILL COOL TO BELOW CLIMO BUT
CONVECTIVE ACTIVITY WILL RAMP UP WITH A GOOD CHANCE FOR SHOWERS AND
TSTMS SATURDAY AND SUNDAY.
&&
.AVIATION /18Z MONDAY THROUGH FRIDAY/...
AS OF 18Z...BIT OF A TRICKY AFTERNOON WITH REGARDS TO CONVECTION.
THE HRRR IS NOT VERY ENTHUSED...WITH MAINLY ISOLATED ACTIVITY THROUGH
THE AFTERNOON. GIVEN THAT WE ARE AROUND OUR CONVECTIVE TEMP...AND
THE FACT THAT THE NAM HAS HIGH POPS...WILL KEEP CONVECTION FAIRLY
PREVALENT ALONG THE COAST...PRESSING INLAND AS THE AFTERNOON WEARS
ON. NOT SURE IF THE SHOWERS WILL MAKE IT TO THE INLAND TERMINALS
SO WILL STICK WITH VCSH. THE NAM IS THE MOST AGGRESSIVE...KEEPING
HIGH POPS ALL THE WAY TO 06Z. THINK THIS IS OVERDONE AND WILL
DISSIPATE MOST OF THE CONVECTION BY 02-03Z. STRATUS WILL BE REINTRODUCED
AFTER MIDNIGHT THROUGH MOST OF THE MORNING HOURS. LOOK FOR THE WINDS
TO SHIFT TO SOUTHERLY AS HIGH PRESSURE MOVES OFFSHORE TUESDAY.
EXTENDED OUTLOOK...PREDOMINANTLY VFR WITH BRIEF MVFR AND POSSIBLY
IFR...IN MORNING FOG...AND ISOLATED/SCATTERED AFTERNOON EARLY
EVENING SHOWERS AND THUNDERSTORMS THROUGH THE EXTENDED.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 128 PM MONDAY...STEADY EAST-NORTHEAST WINDS EXPECTED ACROSS
THE CAROLINA COASTAL WATERS. VEERING WIND DIRECTIONS AND EASING
WIND SPEEDS TONIGHT. LOOK FOR SHOWERS AND STORMS MOVING ACROSS THE
COASTAL WATERS AND BEACHES MAINLY THIS MORNING...WITH SHOWERS
EXPECTED TO DIMINISH IN COVERAGE THIS AFTERNOON. ADDITIONAL
SCATTERED SHOWERS AND STORMS ARE POSSIBLE OVERNIGHT. SEAS
CURRENTLY 2-4 FEET SHOULD DIMINISH TO AROUND 2 FEET LATE TONIGHT.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 AM MONDAY...BROAD HIGH PRESSURE OFF THE SOUTHEAST COAST
WILL CREATE MORE TYPICAL LATE SUMMER CONDITIONS THROUGH MID-
WEEK...WITH RETURN FLOW DRIVING STRENGTHENING S/SW WINDS THROUGH THE
PERIOD. WINDS THE FIRST HALF OF TUESDAY WILL BE LIGHT AND VARIABLE
AS THE PRESSURE PATTERN REMAINS DIFFUSE...BUT AS THE HIGH PRESSURE
OFFSHORE BECOMES MORE SIGNIFICANT...A S/SW DIRECTION WILL BECOME
PREDOMINANT...AND WIND SPEEDS BY WEDNESDAY WILL RISE TO AROUND 15
KTS. WAVE HEIGHTS TUESDAY WILL BE 1-2 FT AS THE VERY LIGHT WINDS
GAIN LITTLE PURCHASE ON SEAS AND SWELL REMAINS INSIGNIFICANT. WAVE
HEIGHTS WILL BUILD TO 2-3 FT WITH ISOLATED 4 FTERS POSSIBLE
WEDNESDAY ON THE INCREASING WINDS AND A GROWING SE GROUND SWELL.
LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 300 AM MONDAY...HIGH PRESSURE OFFSHORE AND A COLD FRONT
APPROACHING FROM THE NW WILL SANDWICH THE COASTAL WATERS THIS
PERIOD. THE COLD FRONT WILL BE ON THE DOORSTEP OF THE LOCAL WATERS
LATE FRIDAY...BUT ANY WIND SHIFT WILL HOLD OFF UNTIL BEYOND THE
EXTENDED. THIS LEAVES SW WINDS THROUGH THE PERIOD...BUT WITH SPEEDS
INCREASING TO 15-20 KTS AS THE GRADIENT TIGHTENS. AN E/SE 9-10 SEC
SWELL WILL EXIST IN THE WAVE SPECTRUM EACH DAY...BUT WILL BECOME
INCREASINGLY SHADOWED BY AN AMPLIFYING 5-SEC SW WIND WAVE.
SIGNIFICANT SEAS WILL BUILD THROUGH THE PERIOD...FROM 2-3 FT EARLY
THURSDAY TO 3-4 FT ON FRIDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...MJC
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...DL/8
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1008 PM EDT SUN SEP 6 2015
.SYNOPSIS...AN UPPER LEVEL LOW WILL RETROGRADE FROM GA TO THE
NORTHERN GULF OF MEXICO TONIGHT...THEN STALL NEAR THE TEXAS GULF
COAST THROUGH MID-WEEK. SURFACE HIGH PRESSURE WILL OTHERWISE WEAKEN
WHILE EXTENDING WEST INTO NC.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1005 PM SUNDAY...
A MID-UPPER LOW OVER GA WILL DRIFT SW AND AWAY FROM CENTRAL NC
TONIGHT...WHILE 1022 MB SURFACE HIGH PRESSURE OFFSHORE THE MIDDLE
ATLANTIC COAST CONTINUES TO EXTEND SW INTO NC. THE AIR MASS OVER
CENTRAL NC IS A STABLE ONE PER 00Z GSO RAOB DATA AND MORE RECENT SPC
MESOANALYSIS DATA. GIVEN THE STABILITY AND LACK OF FORCING FOR
ASCENT...EXCEPT MOISTURE TRANSPORT AND FRICTIONAL CONVERGENCE ALONG
SOUTHEASTERN NC...DRY CONDITIONS ARE EXPECTED OVERNIGHT.
BOTH THE HRRR AND SREF SUGGEST LOW CLOUDS ARE LIKELY TO ADVECT/
DEVELOP SOUTHWESTWARD INTO THE WESTERN HALF OR TWO THIRDS OF THE
FORECAST AREA TONIGHT...WHICH SEEMS REASONABLE GIVEN A RELATIVE LACK
OF LOW CLOUD COVER UPSTREAM IN SE VA AND NE NC...WHERE NWP GUIDANCE
SUGGESTS A TONGUE OF DRY AIR WILL EXTEND...AND LATER DRIFT INTO THE
COASTAL PLAIN.
&&
.SHORT TERM /MONDAY AND MONDAY NIGHT/...
AS OF 300 PM SUNDAY...
THE UPPER LOW IS PROGGED TO BE LOCATED ACROSS THE NORTHEASTERN GULF
OF MEXICO BY 12Z MONDAY...BEFORE RETROGRADING EVEN FURTHER TOWARDS
THE NORTHWESTERN GULF THROUGHOUT THE DAY. AS A RESULT...ANY WEAK
DISTURBANCES THAT ROUND THE EASTERN/NORTHERN PERIPHERY OF THE LOW
SHOULD REMAIN SOUTH/SOUTHWEST OF CENTRAL NC. THEREFORE...CONVECTION
IS EXPECTED TO BE RATHER LIMITED...OUTSIDE OF ANY DIURNAL ACTIVITY.
HIGH TEMPS SHOULD BE SLIGHTLY WARMER GIVEN LESS CLOUDS/PRECIP...
GENERALLY MID/UPPER 80S AND OVERNIGHT LOWS WILL BE SIMILAR TO
PREVIOUS NIGHTS...WITH UPPER 60S TO NEAR 70 DEGREES EXPECTED.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
AS OF 245 PM SUNDAY...
CONTINUED RETROGRESSION OF CUTOFF UPPER LOW TO THE SOUTHWEST OPENS
THE DOOR FOR DEEPER MOISTURE ADVECTION AS AN UPPER TROF DIGS INTO
THE MIDWEST. MEANWHILE...A WEAK SURFACE FRONT WILL BE STALLING OVER
THE AREA WEDNESDAY THROUGH FRIDAY...CONCURRENT WITH PRECIPITABLE
WATER INCREASING FROM <1.5 INCHES TUESDAY TO 1.75-2 INCHES WEDNESDAY
THROUGH FRIDAY. UPPER DYNAMICS ARE NOT PARTICULARLY INVITING FOR
CONVECTION EARLY IN THE PERIOD...BUT WOULD EXPECT TO SEE MORE
COVERAGE AND ORGANIZATION FRIDAY WHEN THE UPPER TROF SHIFTS FAR
ENOUGH EAST TO TIGHTEN UP THE GRADIENTS ASSOCIATED WITH THE STALLED
SURFACE FRONT AS WELL AS INCREASING UPPER JET DIFFLUENCE AND
ENHANCING UPDRAFT POTENTIAL. WILL MAINTAIN POPS IN THE USUAL DIURNAL
PATTERN FROM THE LOW CHANCE CATEGORY TUESDAY INCREASING TO 50% BY
FRIDAY. HIGHS WILL BE AT OR SOMEWHAT ABOVE NORMAL...MID TO UPPER 80S
THROUGH FRIDAY AFTER MORNING LOWS MOSTLY FROM 65 TO 70.
THE UPPER TROF LIFTS OUT AFTER IT HAS NUDGED THE SURFACE FRONT
SOUTHEAST OF THE AREA...WHICH WILL PROVIDE US WITH DRYING AND SOME
WELCOME COOLING FOR THE WEEKEND. HIGHS SHOULD RANGE FROM UPPER 70S
TO LOWER 80S BOTH DAYS WITH SMALL CHANCE POPS MAINLY IN THE
SOUTHEAST.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 140 AM MONDAY...
SUB-VFR STRATUS CONTINUES TO DEVELOP/EXPAND WESTWARD. THIS SHOULD BE
IN THE REGION THROUGH 13Z-15Z WHEN CIGS LIFT TO MVFR THEN VFR.
PATCHY MVFR FOG IS ALSO POSSIBLE THROUGH 12Z-13Z.
GENERALLY VFR CONDITIONS ARE EXPECTED TONIGHT THROUGH TUESDAY.
OUTLOOK WED-FRI...THE CHANCE OF SHOWERS AND THUNDERSTORMS WILL
INCREASE ESPECIALLY LATE IN THE WEEK. IN LATE NIGHT AND MORNING
STRATUS OR FOG WILL BE POSSIBLE.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...26
NEAR TERM...26
SHORT TERM...KRD
LONG TERM...MLM
AVIATION...BADGETT
AREA FORECAST DISCUSSION
NWS BISMARCK ND
859 PM CDT TUE SEP 8 2015
.UPDATE...
ISSUED AT 848 PM CDT TUE SEP 8 2015
AT 830 PM CDT...A COLD FRONTAL BOUNDARY EXTENDED ACROSS SOUTHWEST
SASKATCHEWAN. THE FRONT WILL SLOWLY SLIDE SOUTHEAST TONIGHT AND
WEDNESDAY WITH ONLY A SLOW SOUTHWARD MOVING COMPONENT AS IT
NEARLY ALIGNS WITH THE FLOW ALOFT. LATEST HRRR MODEL RUNS SHOW
SOME SCATTERED SHOWERS ACROSS THE NORTHWEST AFTER 09Z TONIGHT AND
NORTH CENTRAL AFTER 12Z WEDNESDAY. ADDED MORE SLIGHT CHANCE AREA
TO THE NORTHWEST IN CONCERT WITH THE HRRR AFTER 09Z. OTHERWISE
CURRENT FORECAST LOOKS GOOD.
UPDATE ISSUED AT 553 PM CDT TUE SEP 8 2015
THE NORTHERN PLAINS REMAINS ON THE SOUTHERN EDGE OF A LARGE UPPER
LOW ACROSS NORTHERN MANITOBA. THIS HAS MAINTAINED A BREEZY
NORTHWEST FLOW ACROSS THE REGION SO FAR THIS AFTERNOON. AS THE
EVENING APPROACHES EXPECT WINDS TO DIMINISH AFTER 7 PM AND SKIES
TO BECOME MOSTLY CLEAR. UPDATED CURRENT OBSERVATIONS AND SKY
CONDITION ONLY.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 239 PM CDT TUE SEP 8 2015
QUIET WEATHER HIGHLIGHTS THE SHORT TERM FORECAST.
GIVEN GOOD AGREEMENT...UTILIZED A BLEND OF THE 12 UTC GUIDANCE
SUITES. OVERALL...WEAK HIGH PRESSURE ACROSS WESTERN AND CENTRAL
NORTH DAKOTA SOUTH OF THE FILLING NORTHERN MANITOBA LOW WILL
CONTINUE TO WEAKEN THROUGH THE NIGHT. A WEAK IMPULSE EMBEDDED IN
NORTHWEST FLOW ALOFT ON WEDNESDAY MAY SUPPORT ISOLATED RAIN SHOWER
DEVELOPMENT DURING THE AFTERNOON. GIVEN WEAK MID LEVEL LAPSE
RATES...DID NOT INCLUDE A MENTION OF THUNDER AT THIS TIME.
TEMPERATURES WEDNESDAY ARE EXPECTED TO BE SIMILAR TO TODAY WITH
60S NORTH AND 70S SOUTH.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 239 PM CDT TUE SEP 8 2015
NO MAIN CONCERNS IN THE LONG TERM WITH FAIRLY DRY AND QUIET WEATHER
EXPECTED.
EARLY IN THE LONG TERM THE NORTHWEST FLOW ALOFT WITH A FEW UPPER
LEVEL SHORTWAVES...COMBINED WITH A COLD FRONTAL BOUNDARY OVER THE
STATE WILL KEEP SMALL CHANCES OF SHOWERS IN THE FORECAST WEDNESDAY
NIGHT AND THURSDAY. FAIRLY COOL WITH LOWS IN THE UPPER 30S TO UPPER
40S...AND HIGHS MAINLY IN THE 60S.
ANOTHER COOL NIGHT THURSDAY NIGHT AS THE COOL HIGH PRESSURE CENTER
SETTLES OVER THE DAKOTAS BY FRIDAY MORNING. LOWS IN THE MID TO UPPER
30S TO LOWER 40S. THEN A WARMING TREND INTO THE WEEKEND AS THE
WESTERN RIDGE BUILDS BACK INTO THE WESTERN PLAINS.
THE NEXT CHANCE FOR WIDESPREAD SHOWERS SHOULD BE TUESDAY. THE
WESTERN RIDGE WILL BECOME MORE ZONAL OVER THE WEEKEND...THEN
SOUTHWEST FLOW ALOFT RETURNS BY TUESDAY AS AN UPPER LEVEL TROUGH
DIVES SOUTHEAST FROM THE GULF OF ALASKA INTO THE WEST
COAST...DEVELOPING A SURFACE LOW IN THE LEE OF THE ROCKIES BY
TUESDAY MORNING...BRINGING BETTER CHANCES FOR PRECIPITATION NEXT
WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 553 PM CDT TUE SEP 8 2015
SURFACE LOW PRESSURE ACROSS NORTHEAST MONTANA AND AN ASSOCIATED
WEAK AND MOSTLY DRY COLD FRONT WILL MOVE ACROSS NORTHERN NORTH
DAKOTA ON WEDNESDAY. FOR THE 00Z TAF VFR IS EXPECTED. AN INCREASE
IN CLOUDS AOA 5 THOUSAND AGL IS EXPECTED NORTH HALF OF THE STATE
WEDNESDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...AYD
LONG TERM...JV
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
256 PM CDT MON SEP 7 2015
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 256 PM CDT MON SEP 7 2015
RAIN SHOWERS ENDING BY EARLY THIS EVENING CENTRAL HIGHLIGHT THE
SHORT TERM FORECAST.
WILL CONTINUE TO RELY ON A TIME LAGGED ENSEMBLE OF THE HRRR FOR
POPS THE REMAINDER OF THE AFTERNOON...NAMELY ITS 16-18 UTC
ITERATIONS...WHICH HAS DONE WELL THROUGHOUT THE DAY. DID MAINTAIN
A SLIGHT CHANCE OF THUNDER WITH A FEW...SPORADIC LIGHTNING
STRIKES OBSERVED. EXPECT PRECIPITATION CHANCES...FOCUSED PRIMARILY
ACROSS NORTH CENTRAL NORTH DAKOTA AND THE UPPER JAMES RIVER VALLEY
THE REST OF THE DAY...TO RAPIDLY DECREASE BY 22-23 UTC AS FORCING
FROM TWO SHORTWAVES SOUTH OF THE UPPER LOW NEAR LAKE WINNIPEG
SHIFTS EAST.
FOR TUESDAY...A QUIET...DRY...ALBEIT SLIGHTLY BELOW NORMAL
TEMPERATURE-WISE DAY IS FORECAST SOUTH OF THE NOW FILLING
AFOREMENTIONED LOW. GIVEN GOOD AGREEMENT...UTILIZED A BLEND OF THE
12 UTC GUIDANCE SUITES FOR ALL FIELDS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 256 PM CDT MON SEP 7 2015
NORTHWEST FLOW ALOFT THROUGH FRIDAY WITH FLOW ROTATING AROUND THE
HUDSON BAY LOW AND RIDGE OVER THE EASTERN PACIFIC AND WEST COAST.
SHORTWAVE ENERGY MOVING THROUGH THIS FLOW APPROACHES NORTHERN NORTH
DAKOTA LATE TUESDAY NIGHT/WEDNESDAY MORNING...WITH AN ATTENDANT WEAK
SURFACE LOW AND COLD FRONT. MORE SHORTWAVE ENERGY IMPULSES MOVE
SOUTHEAST ACROSS THE STATE WEDNESDAY AFTERNOON WITH A COLD FRONT
MOVING SOUTH ACROSS THE STATE. THIS WILL RESULT IN SLIGHT CHANCES OF
SHOWERS...MAINLY NORTHWEST AND CENTRAL...ON WEDNESDAY. SEASONABLE
TEMPERATURES WEDNESDAY WITH HIGHS FROM THE UPPER 60S NORTH TO UPPER
70S SOUTH.
ANOTHER SERIES OF SHORTWAVES MOVES ACROSS THE STATE WEDNESDAY NIGHT
WITH A SECONDARY PUSH OF COLD AIR IN THE FORM OF A BACKDOOR COLD
FRONT MOVING SOUTHWEST ACROSS THE STATE. SLIGHT CHANCES OF SHOWERS
WILL REMAIN IN THE FORECAST NORTHWEST AND CENTRAL WEDNESDAY
NIGHT...WITH MAINLY DRY BUT COOL CONDITIONS EXPECTED THURSDAY. LOOK
FOR HIGHS IN THE 60S TO LOWER 70S.
THE UPPER LEVEL WESTERN RIDGE BUILDS BACK INTO THE REGION FOR THE
WEEKEND...WITH DRY CONDITIONS AND SLIGHTLY ABOVE AVERAGE
TEMPERATURES. HIGHS IN THE 70S TO LOWER 80S.
THE MODELS BRING AN UPPER LEVEL SHORTWAVE MOVING THROUGH THE
FLOW...FLATTENING THE RIDGE...BRINGING A CHANCE OF SHOWERS AND
COOLER WEATHER FOR MONDAY WITH HIGHS MAINLY IN THE 60S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 256 PM CDT MON SEP 7 2015
VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD. MID LEVEL
CLOUD COVER WILL REMAIN ACROSS MUCH OF CENTRAL AND EASTERN NORTH
DAKOTA THROUGH THE AFTERNOON. LIGHT SHOWERS EXPECTED TO IMPACT KJMS
THROUGH THE AFTERNOON...AND POSSIBLY KMOT BRIEFLY. PATCHY FOG MAY
BE POSSIBLE AT KBIS/KJMS TONIGHT. HOWEVER...GIVEN HIGH
UNCERTAINTY...LEFT IT OUT OF THE TAFS FOR NOW.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...AYD
LONG TERM...JV
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1238 PM CDT MON SEP 7 2015
.UPDATE...
ISSUED AT 1238 PM CDT MON SEP 7 2015
TRICKY TEMP FORECAST AS CLOUDS AND PRECIP MOVING INTO THE
SOUTHWESETERN COUNTIES HAVE KEPT TEMPS COOLER BUT THE NORTHWEST
HAS QUICKLY GONE UP INTO THE 70S. ADJUSTED ACCORDINGLY...LOWERING
HIGHS A FEW DEGREES IN THE SOUTHWEST AND BUMPING THEM UP IN THE
NORTHWEST. WEB CAMS SHOW THE RADAR RETURNS MOVING IN ARE TAKING A
WHILE TO REACH THE GROUND...BUT WESTERN RANSOM AND SARGENT
COUNTIES ARE FINALLY GETTING SOME RAIN. SCATTERED RAIN SHOWERS
WILL CONTINUE TO BE A THREAT THROUGH THIS AFTERNOON...SO BUMPED UP
POPS A BIT.
UPDATE ISSUED AT 934 AM CDT MON SEP 7 2015
TWEAKED POPS TO INCLUDE THE SHOWERS MOVING INTO THE VALLEY CITY
AREA. NOT MUCH IS REACHING THE GROUND...BUT RETURNS ARE STRONG
ENOUGH AS A SHORTWAVE MOVES UP FROM SOUTH DAKOTA TO INCLUDE A
SMALL CHANCE FOR RAIN THROUGHOUT THIS AFTERNOON. OVERALL KEPT THE
TREND OF INCREASING CLOUDS AND HIGHS TOPPING OUT IN THE 60S TO MID
70S.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 348 AM CDT MON SEP 7 2015
THE MAIN CHALLENGE THIS PERIOD WILL BE SHOWER CHANCES AND
TEMPERATURES. THE AIRMASS CHANGE HAS OCCURRED WITH MUCH COOLER
AND DRIER ADVECTING INTO THE REGION. UPPER LOW WILL SLOWLY
PROPAGATE EAST ACROSS CANADA...AND MOST MODEL GUIDANCE SUGGESTS A
WAVE WITHIN THIS FLOW PATTERN WILL LEAD TO SHOWERS THIS AFTERNOON.
GIVEN THE DRY AIRMASS IN PLACE ANY RADAR RETURNS WILL LIKELY
APPEAR WORSE THAN WHAT IS OCCURRING AT THE GROUND...BUT DID
INCLUDE ISOLD SHOWERS AS HRRR INDICATES WEAK BANDING POTENTIAL.
ANTICIPATE SOLAR TODAY...WHICH SHOULD ALLOW MAX TEMPS INTO THE
70S.
DRY ON TUESDAY...AND SLIGHTLY COOLER AS THE UPPER LOW IN CANADA
SHIFTS EAST.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 348 AM CDT MON SEP 7 2015
WEDNESDAY...UPPER WAVE IN NORTHWEST FLOW ALOFT WILL PROVIDE SHOWER
CHANCES...ALTHOUGH MOST 00Z GUIDANCE IS SLOWER AND TIMES THIS
FORCING INTO THE REGION MORE WEDNESDAY NIGHT. THIS WOULD ALLOW
SLIGHTLY WARMER TEMPERATURES DURING THE DAY ON WED. TRENDED THE
FORECAST ACCORDINGLY FOR POPS AND TEMPS.
THURSDAY-SUNDAY...LOW AMPLITUDE LONG WAVE RIDGE/TROUGH OVER
WESTERN CANADA/CENTRAL NORTH AMERICA RESPECTIVELY AMPLIFIES A BIT
BY THE END OF THE PERIOD. THE GFS WAS A FASTER AND A LOWER
AMPLITUDE SOLUTION THAN THE ECMWF. BOTH THE ECMWF AND THE GFS HAVE
BEEN TRENDING SLOWER OVER THE LAST COUPLE MODEL RUNS. TEND TO
PREFER THE ECMWF.
HIGH TEMPS WERE INCREASED ONE TO THREE DEGREES FOR THU AND INCREASED
ONE OR TWO DEGREES FOR FRI AND SAT. HIGH TEMPS WERE DECREASED TWO TO
THREE DEGREES FOR SUN FROM YESTERDAYS FORECAST PACKAGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1238 PM CDT MON SEP 7 2015
A LARGE BATCH OF MID LEVEL CLOUDS WILL MOVE THRU THE AREA THIS
AFTERNOON AND EVENING...AND MAY ALSO DROP A FEW LIGHT SHOWERS.
ECHOES HAVE BEEN DRYING UP AS THEY HAVE MOVED EAST-NE SO AT THIS
POINT WILL ONLY MENTION VCSH AT KFAR/KGFK. OTHERWISE WINDS LOOK TO
REMAIN FAIRLY LOW THROUGHOUT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...TG
LONG TERM...TG/HOPPES
AVIATION...GODON
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1211 PM CDT MON SEP 7 2015
.UPDATE...
ISSUED AT 1205 PM CDT MON SEP 7 2015
INCREASED CLOUD COVER ACROSS MUCH OF CENTRAL NORTH DAKOTA FOR THE
REMAINDER OF THE DAY AHEAD OF TWO SHORTWAVES EMBEDDED IN THE
CYCLONIC FLOW SOUTH OF THE UPPER LOW NORTH OF LAKE WINNIPEG AS OF
17 UTC. AS A RESULT...DID DECREASE HIGHS INTO THE 60S FOR AREAS
TO REMAIN UNDER OVERCAST SKIES. POPS BLENDED TO A TIME LAGGED
ENSEMBLE OF THE 13-15 UTC HRRR ITERATIONS WHICH CONTINUES TO
PERFORM WELL WITH THIS PRECIPITATION EVENT.
UPDATE ISSUED AT 843 AM CDT MON SEP 7 2015
QUICK UPDATE TO BLEND RADAR TRENDS TO THE TIME LAGGED ENSEMBLE OF
THE 10-12 UTC HRRR ITERATIONS...AND ADD AN ISOLATED MENTION OF
THUNDERSTORMS SOUTH CENTRAL THIS MORNING AND THROUGH THE AFTERNOON
WITH A FEW LIGHTNING STRIKES OBSERVED THUS FAR.
UPDATE ISSUED AT 623 AM CDT MON SEP 7 2015
ONLY CHANGE FOR MORNING UPDATE WAS TO TRIM POPS BACK A BIT IN THE
EARLY MORNING AS EXPECT THE ONSET OF SHOWERS WILL BE DELAYED A
LITTLE. OTHERWISE...GOING FORECAST WAS IN GOOD SHAPE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 310 AM CDT MON SEP 7 2015
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL CHANCES FOR
SHOWERS TODAY SOUTHWEST AND CENTRAL...AND COOL/BELOW NORMAL
TEMPERATURES BOTH TODAY AND TUESDAY.
CURRENTLY...UPPER LEVEL LOW PRESSURE SPINNING OVER SOUTHERN
SASKATCHEWAN WITH A 100KT UPPER LEVEL JET ROUNDING THE BASE OF
THE LOW INTO THE WESTERN DAKOTAS. STRONG FLOW ALOFT RESULTING IN
MID LEVEL MOISTURE ADVECTION WITH INCREASING MID AND HIGH LEVEL
CLOUDINESS. DESPITE CLOUDS SOUTHWEST VERY DRY DEWPOINTS IN THE
30S RESULTING IN TEMPERATURES IN THE LOW 40S AND EVEN A FEW UPPER
30S.
THE UPPER JET STREAK IS INDUCING A SUBTLE SURFACE TROUGH OVER
WESTERN SOUTH DAKOTA EARLY THIS MORNING...AND WILL EVENTUALLY
DEVELOP INTO SOUTHWEST AND SOUTH CENTRAL NORTH DAKOTA LATER THIS
MORNING AND AFTERNOON. COUPLED WITH FORCING ALOFT EXPECT SHOWERS
TO DEVELOP NEAR THE TROUGH AXIS AS IT SLOWLY MOVES EAST TODAY.
WHILE WE WILL REALIZE SOME MOISTURE RETURNING BACK INTO THE AREA
INSTABILITY IS VERY MINIMAL SO REMOVED ALL MENTION OF THUNDER FROM
THE FORECAST. FORCING ALOFT MOVES OFF TO OUR EAST AFTER 00Z SO
MAINTAINED A DRY EVENING AND OVERNIGHT PERIOD.
UPPER LOW CONTINUES EAST ACROSS SOUTH CENTRAL CANADA...ROTATING
ANOTHER EMBEDDED WAVE AND ASSOCIATED JET STREAK ACROSS THE STATE
LATE MONDAY NIGHT INTO TUESDAY. AT THIS TIME SFC FORCING LOOKS NIL
WITH SFC HIGH PRESSURE MOVING EAST ACROSS THE REGION SO KEPT THE
TUESDAY MORNING AND AFTERNOON PERIOD DRY FOR NOW.
HIGH TEMPERATURES BOTH TODAY AND TUESDAY VERY COMFORTABLE IN THE
UPPER 60S TO MID 70S. TEMPERATURES TONIGHT SHOULD BE SIMILAR TO
CURRENT CONDITIONS...40S WITH A FEW AREAS DROPPING INTO THE UPPER
30S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 248 AM CDT MON SEP 7 2015
BROAD SHORT WAVE ROTATING AROUND HUDSON BAY LOW PASSES OVER THE
AREA WEDNESDAY AND WEDNESDAY NIGHT...POSSIBLY BRINGING SOME
PRECIPITATION TO OUR AREA. FOR THE REST OF THE WORK
WEEK...NORTHWESTERLY FLOW WITH RIDGING OVER THE WESTERN CONUS WILL
BRING QUIET WEATHER AND COMFORTABLE TEMPERATURES TO THE AREA.
WARMER CONDITIONS RETURN FOR SATURDAY AS RIDGE AXIS PASSES OVER.
BEHIND THE RIDGE...A FEW THUNDERSTORMS MAY DEVELOP INTO SATURDAY
NIGHT. AVERAGE TEMPERATURES RETURN FOR SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1205 PM CDT MON SEP 7 2015
VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD. MID LEVEL
CLOUD COVER WILL REMAIN ACROSS MUCH OF CENTRAL AND EASTERN NORTH
DAKOTA THROUGH THE AFTERNOON. LIGHT SHOWERS EXPECTED TO IMPACTKBIS
AND KJMS THROUGH THE AFTERNOON.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...NH
LONG TERM...JJS
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
934 AM CDT MON SEP 7 2015
.UPDATE...
ISSUED AT 934 AM CDT MON SEP 7 2015
TWEAKED POPS TO INCLUDE THE SHOWERS MOVING INTO THE VALLEY CITY
AREA. NOT MUCH IS REACHING THE GROUND...BUT RETURNS ARE STRONG
ENOUGH AS A SHORTWAVE MOVES UP FROM SOUTH DAKOTA TO INCLUDE A
SMALL CHANCE FOR RAIN THROUGHOUT THIS AFTERNOON. OVERALL KEPT THE
TREND OF INCREASING CLOUDS AND HIGHS TOPPING OUT IN THE 60S TO MID
70S.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 348 AM CDT MON SEP 7 2015
THE MAIN CHALLENGE THIS PERIOD WILL BE SHOWER CHANCES AND
TEMPERATURES. THE AIRMASS CHANGE HAS OCCURRED WITH MUCH COOLER
AND DRIER ADVECTING INTO THE REGION. UPPER LOW WILL SLOWLY
PROPAGATE EAST ACROSS CANADA...AND MOST MODEL GUIDANCE SUGGESTS A
WAVE WITHIN THIS FLOW PATTERN WILL LEAD TO SHOWERS THIS AFTERNOON.
GIVEN THE DRY AIRMASS IN PLACE ANY RADAR RETURNS WILL LIKELY
APPEAR WORSE THAN WHAT IS OCCURRING AT THE GROUND...BUT DID
INCLUDE ISOLD SHOWERS AS HRRR INDICATES WEAK BANDING POTENTIAL.
ANTICIPATE SOLAR TODAY...WHICH SHOULD ALLOW MAX TEMPS INTO THE
70S.
DRY ON TUESDAY...AND SLIGHTLY COOLER AS THE UPPER LOW IN CANADA
SHIFTS EAST.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 348 AM CDT MON SEP 7 2015
WEDNESDAY...UPPER WAVE IN NORTHWEST FLOW ALOFT WILL PROVIDE SHOWER
CHANCES...ALTHOUGH MOST 00Z GUIDANCE IS SLOWER AND TIMES THIS
FORCING INTO THE REGION MORE WEDNESDAY NIGHT. THIS WOULD ALLOW
SLIGHTLY WARMER TEMPERATURES DURING THE DAY ON WED. TRENDED THE
FORECAST ACCORDINGLY FOR POPS AND TEMPS.
THURSDAY-SUNDAY...LOW AMPLITUDE LONG WAVE RIDGE/TROUGH OVER
WESTERN CANADA/CENTRAL NORTH AMERICA RESPECTIVELY AMPLIFIES A BIT
BY THE END OF THE PERIOD. THE GFS WAS A FASTER AND A LOWER
AMPLITUDE SOLUTION THAN THE ECMWF. BOTH THE ECMWF AND THE GFS HAVE
BEEN TRENDING SLOWER OVER THE LAST COUPLE MODEL RUNS. TEND TO
PREFER THE ECMWF.
HIGH TEMPS WERE INCREASED ONE TO THREE DEGREES FOR THU AND INCREASED
ONE OR TWO DEGREES FOR FRI AND SAT. HIGH TEMPS WERE DECREASED TWO TO
THREE DEGREES FOR SUN FROM YESTERDAYS FORECAST PACKAGE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 644 AM CDT MON SEP 7 2015
VFR THROUGH THE PERIOD. CLEAR SKY THIS MORNING WILL GIVE WAY TO
INCREASING MID-LEVEL CLOUDS...THEN LIKELY CLEAR AGAIN BY TUESDAY
MORNING.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...TG
LONG TERM...TG/HOPPES
AVIATION...TG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
846 AM CDT MON SEP 7 2015
.UPDATE...
ISSUED AT 843 AM CDT MON SEP 7 2015
QUICK UPDATE TO BLEND RADAR TRENDS TO THE TIME LAGGED ENSEMBLE OF
THE 10-12 UTC HRRR ITERATIONS...AND ADD AN ISOLATED MENTION OF
THUNDERSTORMS SOUTH CENTRAL THIS MORNING AND THROUGH THE AFTERNOON
WITH A FEW LIGHTNING STRIKES OBSERVED THUS FAR.
UPDATE ISSUED AT 623 AM CDT MON SEP 7 2015
ONLY CHANGE FOR MORNING UPDATE WAS TO TRIM POPS BACK A BIT IN THE
EARLY MORNING AS EXPECT THE ONSET OF SHOWERS WILL BE DELAYED A
LITTLE. OTHERWISE...GOING FORECAST WAS IN GOOD SHAPE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 310 AM CDT MON SEP 7 2015
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL CHANCES FOR
SHOWERS TODAY SOUTHWEST AND CENTRAL...AND COOL/BELOW NORMAL
TEMPERATURES BOTH TODAY AND TUESDAY.
CURRENTLY...UPPER LEVEL LOW PRESSURE SPINNING OVER SOUTHERN
SASKATCHEWAN WITH A 100KT UPPER LEVEL JET ROUNDING THE BASE OF
THE LOW INTO THE WESTERN DAKOTAS. STRONG FLOW ALOFT RESULTING IN
MID LEVEL MOISTURE ADVECTION WITH INCREASING MID AND HIGH LEVEL
CLOUDINESS. DESPITE CLOUDS SOUTHWEST VERY DRY DEWPOINTS IN THE
30S RESULTING IN TEMPERATURES IN THE LOW 40S AND EVEN A FEW UPPER
30S.
THE UPPER JET STREAK IS INDUCING A SUBTLE SURFACE TROUGH OVER
WESTERN SOUTH DAKOTA EARLY THIS MORNING...AND WILL EVENTUALLY
DEVELOP INTO SOUTHWEST AND SOUTH CENTRAL NORTH DAKOTA LATER THIS
MORNING AND AFTERNOON. COUPLED WITH FORCING ALOFT EXPECT SHOWERS
TO DEVELOP NEAR THE TROUGH AXIS AS IT SLOWLY MOVES EAST TODAY.
WHILE WE WILL REALIZE SOME MOISTURE RETURNING BACK INTO THE AREA
INSTABILITY IS VERY MINIMAL SO REMOVED ALL MENTION OF THUNDER FROM
THE FORECAST. FORCING ALOFT MOVES OFF TO OUR EAST AFTER 00Z SO
MAINTAINED A DRY EVENING AND OVERNIGHT PERIOD.
UPPER LOW CONTINUES EAST ACROSS SOUTH CENTRAL CANADA...ROTATING
ANOTHER EMBEDDED WAVE AND ASSOCIATED JET STREAK ACROSS THE STATE
LATE MONDAY NIGHT INTO TUESDAY. AT THIS TIME SFC FORCING LOOKS NIL
WITH SFC HIGH PRESSURE MOVING EAST ACROSS THE REGION SO KEPT THE
TUESDAY MORNING AND AFTERNOON PERIOD DRY FOR NOW.
HIGH TEMPERATURES BOTH TODAY AND TUESDAY VERY COMFORTABLE IN THE
UPPER 60S TO MID 70S. TEMPERATURES TONIGHT SHOULD BE SIMILAR TO
CURRENT CONDITIONS...40S WITH A FEW AREAS DROPPING INTO THE UPPER
30S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 248 AM CDT MON SEP 7 2015
BROAD SHORT WAVE ROTATING AROUND HUDSON BAY LOW PASSES OVER THE
AREA WEDNESDAY AND WEDNESDAY NIGHT...POSSIBLY BRINGING SOME
PRECIPITATION TO OUR AREA. FOR THE REST OF THE WORK
WEEK...NORTHWESTERLY FLOW WITH RIDGING OVER THE WESTERN CONUS WILL
BRING QUIET WEATHER AND COMFORTABLE TEMPERATURES TO THE AREA.
WARMER CONDITIONS RETURN FOR SATURDAY AS RIDGE AXIS PASSES OVER.
BEHIND THE RIDGE...A FEW THUNDERSTORMS MAY DEVELOP INTO SATURDAY
NIGHT. AVERAGE TEMPERATURES RETURN FOR SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 843 AM CDT MON SEP 7 2015
VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD. INCREASING
MID AND HIGH LEVEL CLOUDS THROUGH MONDAY MORNING. LIGHT SHOWERS
POSSIBLE MONDAY MORNING/AFTERNOON FOR KBIS-KJMS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...NH
LONG TERM...JJS
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
644 AM CDT MON SEP 7 2015
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 348 AM CDT MON SEP 7 2015
THE MAIN CHALLENGE THIS PERIOD WILL BE SHOWER CHANCES AND
TEMPERATURES. THE AIRMASS CHANGE HAS OCCURRED WITH MUCH COOLER
AND DRIER ADVECTING INTO THE REGION. UPPER LOW WILL SLOWLY
PROPAGATE EAST ACROSS CANADA...AND MOST MODEL GUIDANCE SUGGESTS A
WAVE WITHIN THIS FLOW PATTERN WILL LEAD TO SHOWERS THIS AFTERNOON.
GIVEN THE DRY AIRMASS IN PLACE ANY RADAR RETURNS WILL LIKELY
APPEAR WORSE THAN WHAT IS OCCURRING AT THE GROUND...BUT DID
INCLUDE ISOLD SHOWERS AS HRRR INDICATES WEAK BANDING POTENTIAL.
ANTICIPATE SOLAR TODAY...WHICH SHOULD ALLOW MAX TEMPS INTO THE
70S.
DRY ON TUESDAY...AND SLIGHTLY COOLER AS THE UPPER LOW IN CANADA
SHIFTS EAST.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 348 AM CDT MON SEP 7 2015
WEDNESDAY...UPPER WAVE IN NORTHWEST FLOW ALOFT WILL PROVIDE SHOWER
CHANCES...ALTHOUGH MOST 00Z GUIDANCE IS SLOWER AND TIMES THIS
FORCING INTO THE REGION MORE WEDNESDAY NIGHT. THIS WOULD ALLOW
SLIGHTLY WARMER TEMPERATURES DURING THE DAY ON WED. TRENDED THE
FORECAST ACCORDINGLY FOR POPS AND TEMPS.
THURSDAY-SUNDAY...LOW AMPLITUDE LONG WAVE RIDGE/TROUGH OVER
WESTERN CANADA/CENTRAL NORTH AMERICA RESPECTIVELY AMPLIFIES A BIT
BY THE END OF THE PERIOD. THE GFS WAS A FASTER AND A LOWER
AMPLITUDE SOLUTION THAN THE ECMWF. BOTH THE ECMWF AND THE GFS HAVE
BEEN TRENDING SLOWER OVER THE LAST COUPLE MODEL RUNS. TEND TO
PREFER THE ECMWF.
HIGH TEMPS WERE INCREASED ONE TO THREE DEGREES FOR THU AND INCREASED
ONE OR TWO DEGREES FOR FRI AND SAT. HIGH TEMPS WERE DECREASED TWO TO
THREE DEGREES FOR SUN FROM YESTERDAYS FORECAST PACKAGE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 644 AM CDT MON SEP 7 2015
VFR THROUGH THE PERIOD. CLEAR SKY THIS MORNING WILL GIVE WAY TO
INCREASING MID-LEVEL CLOUDS...THEN LIKELY CLEAR AGAIN BY TUESDAY
MORNING.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...TG
LONG TERM...TG/HOPPES
AVIATION...TG
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
348 AM CDT MON SEP 7 2015
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 348 AM CDT MON SEP 7 2015
THE MAIN CHALLENGE THIS PERIOD WILL BE SHOWER CHANCES AND
TEMPERATURES. THE AIRMASS CHANGE HAS OCCURRED WITH MUCH COOLER
AND DRIER ADVECTING INTO THE REGION. UPPER LOW WILL SLOWLY
PROPAGATE EAST ACROSS CANADA...AND MOST MODEL GUIDANCE SUGGESTS A
WAVE WITHIN THIS FLOW PATTERN WILL LEAD TO SHOWERS THIS AFTERNOON.
GIVEN THE DRY AIRMASS IN PLACE ANY RADAR RETURNS WILL LIKELY
APPEAR WORSE THAN WHAT IS OCCURRING AT THE GROUND...BUT DID
INCLUDE ISOLD SHOWERS AS HRRR INDICATES WEAK BANDING POTENTIAL.
ANTICIPATE SOLAR TODAY...WHICH SHOULD ALLOW MAX TEMPS INTO THE
70S.
DRY ON TUESDAY...AND SLIGHTLY COOLER AS THE UPPER LOW IN CANADA
SHIFTS EAST.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 348 AM CDT MON SEP 7 2015
WEDNESDAY...UPPER WAVE IN NORTHWEST FLOW ALOFT WILL PROVIDE SHOWER
CHANCES...ALTHOUGH MOST 00Z GUIDANCE IS SLOWER AND TIMES THIS
FORCING INTO THE REGION MORE WEDNESDAY NIGHT. THIS WOULD ALLOW
SLIGHTLY WARMER TEMPERATURES DURING THE DAY ON WED. TRENDED THE
FORECAST ACCORDINGLY FOR POPS AND TEMPS.
THURSDAY-SUNDAY...LOW AMPLITUDE LONG WAVE RIDGE/TROUGH OVER
WESTERN CANADA/CENTRAL NORTH AMERICA RESPECTIVELY AMPLIFIES A BIT
BY THE END OF THE PERIOD. THE GFS WAS A FASTER AND A LOWER
AMPLITUDE SOLUTION THAN THE ECMWF. BOTH THE ECMWF AND THE GFS HAVE
BEEN TRENDING SLOWER OVER THE LAST COUPLE MODEL RUNS. TEND TO
PREFER THE ECMWF.
HIGH TEMPS WERE INCREASED ONE TO THREE DEGREES FOR THU AND INCREASED
ONE OR TWO DEGREES FOR FRI AND SAT. HIGH TEMPS WERE DECREASED TWO TO
THREE DEGREES FOR SUN FROM YESTERDAYS FORECAST PACKAGE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1145 PM CDT SUN SEP 6 2015
VFR THRU THE PERIOD. GENERALLY CLEAR WITH LIGHT WINDS OVERNIGHT.
COULD BE PATCHY RADIATIONAL FOG NR SUNRISE BEMIDJI AREA...BUT
CONFIDENCE IS QUITE LOW AND ANY FOG WILL BE SPOTTY SO WILL KEEP
VSBY P6SM. OTHERWISE INCREASE IN HIGH AND MID CLOUDS THRU THE DAY
MONDAY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...TG
LONG TERM...TG/HOPPES
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1148 PM CDT SUN SEP 6 2015
.UPDATE...
ISSUED AT 1145 PM CDT SUN SEP 6 2015
SKIES CLEAR AND WINDS BECOMING LIGHT. SOME THIN CIRRUS ENTERING
WRN ND AND WILL SPREAD NORTHEAST OVERNIGHT. LATEST HRRR MODEL RUNS
DONT INDICATE ANY FOG...SO WILL NOT MENTION. WILL STILL NEED TO
KEEP AN EYE ON IT THOUGH IN THE FAR EASTERN FCST AREA.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 350 PM CDT SUN SEP 6 2015
REST OF THE AFTERNOON AND EVENING...A WEAK FRONTAL BOUNDARY DRAPED
ALONG THE BDE-BJI-PKD-ETH LINE WILL SLOWLY SHIFT EASTWARD AND
PROVIDE SOME FOCUS FOR STRONG SHOWER AND THUNDERSTORM DEVELOPMENT.
BEHIND THIS BOUNDARY IN NORTHWEST MINNESOTA... ISOLATED ELEVATED
CONVECTION IS POSSIBLE THROUGH THE LATE AFTERNOON PERIOD. BY 00Z
THUNDERSTORM ACTIVITY WILL HAVE MOVED INTO CENTRAL AND EASTERN
PORTIONS OF MINNESOTA... WITH A SOMEHWAT DRIER WESTERLY FLOW
PERSISTING INTO THE OVERNIGHT HOURS.
LABOR DAY...SOME PATCHY GROUND FOG IS POSSIBLE OVER THE MINNESOTA
LAKES COUNTRY IN THE EARLY MORNING. OTHERWISE...EXPECT GENERALLY
FAIR SKIES INTO MIDDAY AND SEASONABLY MILD CONDITIONS THROUGHOUT
THE DAY. A LIGHT SOUTHERLY BREEZE WILL TURN LIGHT AND VARIABLE
THROUGH THE AFTERNOON AS SURFACE HIGH PRESSURE MOVES INTO CENTRAL
MINNESOTA. AREAS OF FAIRLY HIGH BASED AND SHALLOW CUMULUS CLOUDS
WILL LIKELY DEVELOP IN THE AFTERNOON... AND AN ISOLATED SPRINKLE
IS POSSIBLE... BUT MEASURABLE PRECIPITATION IS NOT EXPECTED.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 350 PM CDT SUN SEP 6 2015
TUESDAY THROUGH WEDNESDAY...A FAIRLY BROAD AND SHALLOW H5 TROF
SETS UP ACROSS THE NORTHERN PLAINS FOR THE EARLY WEEK PERIOD WITH
WEST-NORTHWESTERLY FLOW ALOFT OVER THE AREA. MODELS ARE FAIRLY
CONSISTENT IN MAINTAINING AN OVERALL DRY FLOW OVER MOST OF THE
DAK-MINN AREA THROUGH TUESDAY... WITH SOME MOISTURE AND ENERGY
DROPPING INTO THE AREA ON WEDNESDAY.
WEDNESDAY NIGHT THROUGH SUNDAY...FLOW TRANSITIONS FROM TROUGHING
AND NORTHWESTERLY FLOW ALOFT TO MORE ZONAL AS A TROUGH DIGS INTO
THE UPPER MIDWEST AND THEN MOVES EAST. SOME SHOWERS WILL LINGER
INTO WEDNESDAY NIGHT AND THURSDAY AS A REINFORCING SURGE OF COOL
AIR COMES DOWN...BUT THE END OF THE WEEK SHOULD BE DRY. LOWERED
THE BLENDED POPS A BIT TO REMOVE MENTION OF PRECIP THURSDAY NIGHT
AND FRIDAY AS WE SHOULD BE FIRMLY UNDER HIGH PRESSURE BY THEN.
ANOTHER APPROACHING FRONT ON SUNDAY COULD BRING A CHANCE FOR
PRECIP...BUT WITH A LOT OF VARIATION ON TIMING KEPT CHANCES LOW.
TEMPS WILL BE COOLER THAN AVERAGE AT THE START OF THE PERIOD BUT
WILL WARM UP INTO NEXT WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1145 PM CDT SUN SEP 6 2015
VFR THRU THE PERIOD. GENERALLY CLEAR WITH LIGHT WINDS OVERNIGHT.
COULD BE PATCHY RADITIONAL FOG NR SUNRISE BEMIDJI AREA...BUT
CONFIDENCE IS QUITE LOW AND ANY FOG WILL BE SPOTTY SO WILL KEEP
VSBY P6SM. OTHERWISE INCREASE IN HIGH AND MID CLOUDS THRU THE DAY
MONDAY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...RIDDLE
SHORT TERM...GUST
LONG TERM...GUST/JR
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS NORMAN OK
1218 PM CDT MON SEP 7 2015
.AVIATION...
18Z TAFS... VFR CONDITIONS EXPECTED THIS TAF PERIOD WITH SOME MID
AND HIGH CLOUDS. A FEW SHOWERS/STORMS MAY AFFECT PARTS OF NW OK
TUESDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 614 AM CDT MON SEP 7 2015/
DISCUSSION...
AVIATION DISCUSSION FOR THE 12Z TAFS IS BELOW.
AVIATION...
VFR CONDITIONS ARE EXPECTED TO CONTINUE.
MBS
PREV DISCUSSION... /ISSUED 347 AM CDT MON SEP 7 2015/
DISCUSSION...
HOT WEATHER TODAY AND TUESDAY IS THE FIRST CONCERN...THEN RAIN
CHANCES MAINLY TUESDAY...WEDNESDAY...AND THURSDAY NIGHT AS WELL
AS COOLER WEATHER ARE THE NEXT CONCERNS.
THIS MORNING...LATEST HRRR RUNS HAVE BEEN HINTING THAT A FEW
HIGH BASED SHOWERS AND THUNDERSTORMS MAY FORM OVER NORTHERN
OKLAHOMA...NORTH OF A ELK CITY TO STILLWATER LINE. FOR NOW...DID
NOT MENTION AS NOT SURE THIS WILL OCCUR DUE TO DECENT CAPPING.
THIS AFTERNOON AND EARLY EVENING...A FEW THUNDERSTORMS MAY FORM
SIMILAR TO YESTERDAY IN PARTS OF SOUTHERN OKLAHOMA...MAINLY SOUTH
OF A ARDMORE TO COALGATE LINE AS WELL AS PERHAPS FAR NORTHWESTERN
OKLAHOMA CLOSER TO A FRONT. KEPT 20 PERCENT CHANCES IN THESE
LOCATIONS. ANY STORM WILL MOVE FAIRLY SLOWLY AND BE CAPABLE OF
PRODUCING GUSTY WINDS UP TO 50 MPH AND WELL AS LOCALIZED
DOWNPOURS.
THE HEAT TODAY WILL BE THE MAIN STORY. THINK HIGHS WILL BE VERY
SIMILAR TO YESTERDAY. GENERALLY WENT TOWARDS THE HOTTER SIDE OF
MODEL GUIDANCE. WILL HOLD OFF ON ISSUING A HEAT ADVISORY THOUGH
HEAT INDICES WILL FLIRT WITH THE 105 DEGREE MARK IN MANY
LOCATIONS.
LATE TONIGHT INTO TUESDAY MORNING...A FEW STORMS MAY FORM NEAR
THE APPROACHING COLD FRONT IN NORTHERN OKLAHOMA. KEPT 20 PERCENT
CHANCES TO ACCOUNT FOR THIS. OTHERWISE...RAINFREE AND MUGGY
CONDITIONS WILL PERSIST.
TUESDAY AFTERNOON AND NIGHT...RAIN CHANCES WILL INCREASE ACROSS
THE ENTIRE AREA WITH THE PASSAGE OF A COLD FRONT. STORMS MAY BE
NEAR THE FRONT AND PERHAPS ORGANIZE INTO A LINE. A FEW STORMS MAY
BE STRONG TO PERHAPS SEVERE WITH DAMAGING WINDS UP TO 70 MPH AS
THE MAIN HAZARDS AS DCAPE VALUES WILL EXCEED 1000 J/KG IN A HOT
DEEPLY MIXED ENVIRONMENT. NOT SURE IF STORMS WILL BECOME TOO
WIDESPREAD AND VERY ORGANIZED AS 0-6 KM SHEAR MAY BE MARGINAL.
LOCALLY HEAVY RAINFALL COULD OCCUR AS WELL. HIGHEST RAIN CHANCES
APPEAR TO BE NEAR AND EAST OF I-35.
HIGHS ON TUESDAY MAY SOAR JUST AHEAD OF THE COLD FRONT...THUS WENT
ABOVE MODEL GUIDANCE IN MOST LOCATIONS EXCEPT FAR NORTHERN
OKLAHOMA WHERE MORE CLOUDS AND RAIN MAY KEEP THEM DOWN A BIT.
WEDNESDAY...SOME SHOWERS AND STORMS MAY LINGER OVER SOUTHERN
OKLAHOMA AND WESTERN NORTH TEXAS...MAINLY DURING THE MORNING
HOURS. COOLER TEMPERATURES WILL LIKELY RESULT...THOUGH IT MAY
REMAIN FAIRLY MUGGY.
WEDNESDAY NIGHT THROUGH SUNDAY...COOLER WEATHER IS STILL
FORECAST...THOUGH THERE IS SOME UNCERTAINTY DURING THIS TIME FRAME
WITH THE TIMING OF SYSTEMS AND HOW COOL IT WILL BE. LATEST MODELS
WERE NOT QUITE AS COOL DURING THIS TIME FRAME. THERE SEEMED TO BE
SIGNAL FOR STORMS THURSDAY NIGHT ACROSS MUCH OF THE AREA. RAIN
CHANCES WERE KEPT THURSDAY NIGHT THROUGH SATURDAY NIGHT ACROSS
PARTS OF THE AREA...THOUGH TIMING AND LOCATIONS REMAIN UNCERTAIN.
MBS
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 98 74 96 69 / 10 10 30 60
HOBART OK 103 75 99 69 / 0 10 30 50
WICHITA FALLS TX 99 73 100 72 / 10 0 10 60
GAGE OK 101 76 94 64 / 10 10 40 30
PONCA CITY OK 98 77 91 67 / 10 10 50 70
DURANT OK 97 74 97 72 / 20 20 20 70
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
30/25/25
AREA FORECAST DISCUSSION
NWS NORMAN OK
614 AM CDT MON SEP 7 2015
.DISCUSSION...
AVIATION DISCUSSION FOR THE 12Z TAFS IS BELOW.
&&
.AVIATION...
VFR CONDITIONS ARE EXPECTED TO CONTINUE.
MBS
&&
.PREV DISCUSSION... /ISSUED 347 AM CDT MON SEP 7 2015/
DISCUSSION...
HOT WEATHER TODAY AND TUESDAY IS THE FIRST CONCERN...THEN RAIN
CHANCES MAINLY TUESDAY...WEDNESDAY...AND THURSDAY NIGHT AS WELL
AS COOLER WEATHER ARE THE NEXT CONCERNS.
THIS MORNING...LATEST HRRR RUNS HAVE BEEN HINTING THAT A FEW
HIGH BASED SHOWERS AND THUNDERSTORMS MAY FORM OVER NORTHERN
OKLAHOMA...NORTH OF A ELK CITY TO STILLWATER LINE. FOR NOW...DID
NOT MENTION AS NOT SURE THIS WILL OCCUR DUE TO DECENT CAPPING.
THIS AFTERNOON AND EARLY EVENING...A FEW THUNDERSTORMS MAY FORM
SIMILAR TO YESTERDAY IN PARTS OF SOUTHERN OKLAHOMA...MAINLY SOUTH
OF A ARDMORE TO COALGATE LINE AS WELL AS PERHAPS FAR NORTHWESTERN
OKLAHOMA CLOSER TO A FRONT. KEPT 20 PERCENT CHANCES IN THESE
LOCATIONS. ANY STORM WILL MOVE FAIRLY SLOWLY AND BE CAPABLE OF
PRODUCING GUSTY WINDS UP TO 50 MPH AND WELL AS LOCALIZED
DOWNPOURS.
THE HEAT TODAY WILL BE THE MAIN STORY. THINK HIGHS WILL BE VERY
SIMILAR TO YESTERDAY. GENERALLY WENT TOWARDS THE HOTTER SIDE OF
MODEL GUIDANCE. WILL HOLD OFF ON ISSUING A HEAT ADVISORY THOUGH
HEAT INDICES WILL FLIRT WITH THE 105 DEGREE MARK IN MANY
LOCATIONS.
LATE TONIGHT INTO TUESDAY MORNING...A FEW STORMS MAY FORM NEAR
THE APPROACHING COLD FRONT IN NORTHERN OKLAHOMA. KEPT 20 PERCENT
CHANCES TO ACCOUNT FOR THIS. OTHERWISE...RAINFREE AND MUGGY
CONDITIONS WILL PERSIST.
TUESDAY AFTERNOON AND NIGHT...RAIN CHANCES WILL INCREASE ACROSS
THE ENTIRE AREA WITH THE PASSAGE OF A COLD FRONT. STORMS MAY BE
NEAR THE FRONT AND PERHAPS ORGANIZE INTO A LINE. A FEW STORMS MAY
BE STRONG TO PERHAPS SEVERE WITH DAMAGING WINDS UP TO 70 MPH AS
THE MAIN HAZARDS AS DCAPE VALUES WILL EXCEED 1000 J/KG IN A HOT
DEEPLY MIXED ENVIRONMENT. NOT SURE IF STORMS WILL BECOME TOO
WIDESPREAD AND VERY ORGANIZED AS 0-6 KM SHEAR MAY BE MARGINAL.
LOCALLY HEAVY RAINFALL COULD OCCUR AS WELL. HIGHEST RAIN CHANCES
APPEAR TO BE NEAR AND EAST OF I-35.
HIGHS ON TUESDAY MAY SOAR JUST AHEAD OF THE COLD FRONT...THUS WENT
ABOVE MODEL GUIDANCE IN MOST LOCATIONS EXCEPT FAR NORTHERN
OKLAHOMA WHERE MORE CLOUDS AND RAIN MAY KEEP THEM DOWN A BIT.
WEDNESDAY...SOME SHOWERS AND STORMS MAY LINGER OVER SOUTHERN
OKLAHOMA AND WESTERN NORTH TEXAS...MAINLY DURING THE MORNING
HOURS. COOLER TEMPERATURES WILL LIKELY RESULT...THOUGH IT MAY
REMAIN FAIRLY MUGGY.
WEDNESDAY NIGHT THROUGH SUNDAY...COOLER WEATHER IS STILL
FORECAST...THOUGH THERE IS SOME UNCERTAINTY DURING THIS TIME FRAME
WITH THE TIMING OF SYSTEMS AND HOW COOL IT WILL BE. LATEST MODELS
WERE NOT QUITE AS COOL DURING THIS TIME FRAME. THERE SEEMED TO BE
SIGNAL FOR STORMS THURSDAY NIGHT ACROSS MUCH OF THE AREA. RAIN
CHANCES WERE KEPT THURSDAY NIGHT THROUGH SATURDAY NIGHT ACROSS
PARTS OF THE AREA...THOUGH TIMING AND LOCATIONS REMAIN UNCERTAIN.
MBS
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 99 74 96 69 / 10 10 30 60
HOBART OK 103 75 101 69 / 0 10 30 50
WICHITA FALLS TX 100 73 100 72 / 10 0 10 60
GAGE OK 101 76 94 64 / 10 10 40 30
PONCA CITY OK 99 77 91 67 / 10 10 50 70
DURANT OK 97 74 97 72 / 20 20 20 70
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
17
AREA FORECAST DISCUSSION
NWS NORMAN OK
347 AM CDT MON SEP 7 2015
.DISCUSSION...
HOT WEATHER TODAY AND TUESDAY IS THE FIRST CONCERN...THEN RAIN
CHANCES MAINLY TUESDAY...WEDNESDAY...AND THURSDAY NIGHT AS WELL
AS COOLER WEATHER ARE THE NEXT CONCERNS.
THIS MORNING...LATEST HRRR RUNS HAVE BEEN HINTING THAT A FEW
HIGH BASED SHOWERS AND THUNDERSTORMS MAY FORM OVER NORTHERN
OKLAHOMA...NORTH OF A ELK CITY TO STILLWATER LINE. FOR NOW...DID
NOT MENTION AS NOT SURE THIS WILL OCCUR DUE TO DECENT CAPPING.
THIS AFTERNOON AND EARLY EVENING...A FEW THUNDERSTORMS MAY FORM
SIMILAR TO YESTERDAY IN PARTS OF SOUTHERN OKLAHOMA...MAINLY SOUTH
OF A ARDMORE TO COALGATE LINE AS WELL AS PERHAPS FAR NORTHWESTERN
OKLAHOMA CLOSER TO A FRONT. KEPT 20 PERCENT CHANCES IN THESE
LOCATIONS. ANY STORM WILL MOVE FAIRLY SLOWLY AND BE CAPABLE OF
PRODUCING GUSTY WINDS UP TO 50 MPH AND WELL AS LOCALIZED
DOWNPOURS.
THE HEAT TODAY WILL BE THE MAIN STORY. THINK HIGHS WILL BE VERY
SIMILAR TO YESTERDAY. GENERALLY WENT TOWARDS THE HOTTER SIDE OF
MODEL GUIDANCE. WILL HOLD OFF ON ISSUING A HEAT ADVISORY THOUGH
HEAT INDICES WILL FLIRT WITH THE 105 DEGREE MARK IN MANY
LOCATIONS.
LATE TONIGHT INTO TUESDAY MORNING...A FEW STORMS MAY FORM NEAR
THE APPROACHING COLD FRONT IN NORTHERN OKLAHOMA. KEPT 20 PERCENT
CHANCES TO ACCOUNT FOR THIS. OTHERWISE...RAINFREE AND MUGGY
CONDITIONS WILL PERSIST.
TUESDAY AFTERNOON AND NIGHT...RAIN CHANCES WILL INCREASE ACROSS
THE ENTIRE AREA WITH THE PASSAGE OF A COLD FRONT. STORMS MAY BE
NEAR THE FRONT AND PERHAPS ORGANIZE INTO A LINE. A FEW STORMS MAY
BE STRONG TO PERHAPS SEVERE WITH DAMAGING WINDS UP TO 70 MPH AS
THE MAIN HAZARDS AS DCAPE VALUES WILL EXCEED 1000 J/KG IN A HOT
DEEPLY MIXED ENVIRONMENT. NOT SURE IF STORMS WILL BECOME TOO
WIDESPREAD AND VERY ORGANIZED AS 0-6 KM SHEAR MAY BE MARGINAL.
LOCALLY HEAVY RAINFALL COULD OCCUR AS WELL. HIGHEST RAIN CHANCES
APPEAR TO BE NEAR AND EAST OF I-35.
HIGHS ON TUESDAY MAY SOAR JUST AHEAD OF THE COLD FRONT...THUS WENT
ABOVE MODEL GUIDANCE IN MOST LOCATIONS EXCEPT FAR NORTHERN
OKLAHOMA WHERE MORE CLOUDS AND RAIN MAY KEEP THEM DOWN A BIT.
WEDNESDAY...SOME SHOWERS AND STORMS MAY LINGER OVER SOUTHERN
OKLAHOMA AND WESTERN NORTH TEXAS...MAINLY DURING THE MORNING
HOURS. COOLER TEMPERATURES WILL LIKELY RESULT...THOUGH IT MAY
REMAIN FAIRLY MUGGY.
WEDNESDAY NIGHT THROUGH SUNDAY...COOLER WEATHER IS STILL
FORECAST...THOUGH THERE IS SOME UNCERTAINTY DURING THIS TIME FRAME
WITH THE TIMING OF SYSTEMS AND HOW COOL IT WILL BE. LATEST MODELS
WERE NOT QUITE AS COOL DURING THIS TIME FRAME. THERE SEEMED TO BE
SIGNAL FOR STORMS THURSDAY NIGHT ACROSS MUCH OF THE AREA. RAIN
CHANCES WERE KEPT THURSDAY NIGHT THROUGH SATURDAY NIGHT ACROSS
PARTS OF THE AREA...THOUGH TIMING AND LOCATIONS REMAIN UNCERTAIN.
MBS
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 99 74 96 69 / 10 10 30 60
HOBART OK 103 75 101 69 / 0 10 30 50
WICHITA FALLS TX 100 73 100 72 / 10 0 10 60
GAGE OK 101 76 94 64 / 10 10 40 30
PONCA CITY OK 99 77 91 67 / 10 10 50 70
DURANT OK 97 74 97 72 / 20 20 20 70
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
17
AREA FORECAST DISCUSSION
NWS TULSA OK
1135 PM CDT SUN SEP 6 2015
.DISCUSSION...
The 06z TAF discussion is included below...
&&
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
The theme of the 00z forecast remains in tact. Still some
potential as suggested in the latest runs of the HRRR that some
high based tsra is possible toward 12z across NE OK. Some light
mvfr fog is possible near sunrise at KBVO, KFYV, and KROG.
Afternoon isolated storms are expected to develop in the terrain
again over in SE OK and NW AR...with KFSM standing the greatest
risk of being affected. For both convective scenarios...confidence
and coverage were not great enough to go with TEMPO...so will
instead go the conservative VCTS route.
Lacy
&&
.PREV DISCUSSION... /ISSUED 738 PM CDT SUN SEP 6 2015/
DISCUSSION...
Sent out an early update this evening as area 88Ds indicate afternoon
convection has pretty much all dissipated at this time, so we
removed mention of thunderstorms this evening. As previous discussion
indicated, we have also added slight chance POPs for nern OK and far
nwrn AR late tonight/Monday morning. Short-term models hint at some
high-based convection developing into our CWA after 09z as mid-levels
moisten/destabilize. Will likely result in a bit more cloudiness
Monday morning but not enough to impact expected max temperatures
later in the day. Updated products already issued...
PREV DISCUSSION... /ISSUED 705 PM CDT SUN SEP 6 2015/
DISCUSSION...
The 00z taf discussion is included below...
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
Ridging remains in place aloft...which will maintain VFR
conditions for the most part thru this forecast period.
However...there are a few possible exceptions or things to note.
The latest data indicates mid level moistening that could produce
some high based thunderstorms around sunrise and into the morning
hours across NE OK. In addition...some light MVFR fog is possible
over in NW AR around sunrise as well. By tomorrow
afternoon...daytime heating will produce isolated thunderstorms
over in the terrain of SE OK/W AR. KFSM stands the best chance of
being affected. With both of the convective scenarios
discussed...confidence and coverage would suggest staying
conservative...so will use VCTS mention instead of prob30 or TEMPO
for now.
Lacy
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 75 96 76 93 / 20 20 10 20
FSM 75 96 74 93 / 10 20 10 20
MLC 75 96 75 94 / 10 10 10 20
BVO 70 95 71 91 / 20 20 10 40
FYV 69 90 71 89 / 10 10 10 30
BYV 69 91 70 89 / 10 20 10 30
MKO 74 95 74 93 / 10 10 10 20
MIO 74 94 75 90 / 20 20 10 40
F10 75 96 75 94 / 10 10 10 20
HHW 75 97 74 95 / 10 20 10 20
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...30
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1134 PM EDT TUE SEP 8 2015
.SYNOPSIS...
HIGH PRESSURE THAT BROUGHT US THIS RECENT STRING OF DRY AND VERY
WARM DAYS WILL DRIFT OFF THE EAST COAST. A COLD FRONT WILL MOVE
SLOWLY EAST ACROSS THE REGION WEDNESDAY AFTERNOON AND NIGHT. A
WAVE OF LOW PRESSURE WILL FORM ALONG THIS FRONT AND BRING A
SHOWERY AND MUCH COOLER DAY FOR THURSDAY. MAINLY DRY AND
SEASONABLY COOL CONDITIONS WILL FOLLOW FOR LATER THURSDAY NIGHT
THROUGH FRIDAY. A DEEP TROUGH WILL FORM OVER THE OHIO AND
TENNESSEE VALLEYS SATURDAY...THEN MOVE SLOWLY TO THE NORTHEAST
SUNDAY AND MONDAY BRINGING THE POTENTIAL FOR LOCALLY HEAVY RAIN.
&&
.NEAR TERM /UNTIL 8 AM WEDNESDAY MORNING/...
10 PM UPDATE...
TEMPS COOLING OFF QUICKLY - SOME MESO OBS AROUND STATE COLLEGE ARE
20 DEGREES COOLER THAN THE MAXES. 95F WAS THE HOTTEST DAY IN TWO
YEARS AT HARRISBURG...BUT NO RECORD MAX FOR THEM SINCE THE RECORD
FOR THE DAY IS 99F.
STILL A COUPLE OF VERY LIGHT SHOWERS ALONG THE HIGHER RIDGELINES
OF THE LAURELS AND ALLEGHENIES. HOWEVER...WITH 50-SOMETHING
DEWPOINTS AND CLOUD CEILINGS AOA 8KFT IN THAT AREA...CAN/T IMAGINE
MUCH IS REACHING THE GROUND. ONE ECHO JUST PASSED RIGHT OVER KFIG
AND DID MAKE A TRACE /LESS THAN ONE HUNDRETH OF AN INCH/ THERE.
EXPECT THAT SOME OF THESE VERY LIGHT AND QUICK-MOVING SHOWERS WILL
CONTINUE THROUGH MIDNIGHT OR A FEW HOURS INTO THE NEW DAY.
HOWEVER...A 20 POP COULD EVEN BE OVERDONE AS THE LIKELIHOOD OF
MEASURING IS EXTREMELY LOW AND COVERAGE VERY VERY SPARSE.
8 PM UPDATE...
CLOUDS NOT GOING AWAY ALONG THE ALLEGHENY FRONT AND ARE EVEN
DEVELOPING/GROWING SLIGHTLY. SPECKLES OF REFLECTIVITY ARE STARTING
TO SHOW UP ON RADAR AS WELL...EVEN NEAR KMDT. NAM AND HRRR HAS
THIS - PERHAPS OVER DOING IT - GENERATING SOME QPF OVER MOST OF
THOSE HIGHER ELEVATIONS IN THE ALLEGHENIES OVER THE NEXT 3-4HRS.
THE LOW/MID LEVEL FLOW IS INCREASING SLIGHTLY AND COULD BE RUNNING
INTO LIGHTER FLOW OUT OF THE SOUTHWEST. THE WINDS THEN BECOME
MORE- ALIGNED IN THE LOWEST 10KFT LATER TONIGHT. LOWEST CLOUD DECK
IS ABOUT 8KFT...SO WILL COUNT ON ANY RAIN FALLING FROM THEM TO
MOSTLY DRY UP BEFORE IT GETS TO THE GROUND. STILL...A VERY LIGHT
SHOWER IS POSSIBLE THERE FOR THE NEXT FEW HOURS.
FROM PREV...
SOME OF THE HIGHEST TERRAIN ACROSS THE WEST COULD SEE THE SW WIND
STAY UP AT AROUND 5-8 KTS TONIGHT AS THE LLVL P-GRADIENT TIGHTENS
A BIT.
LOW TEMPS TONIGHT WILL VARY FROM THE LOWER 60S ACROSS THE NRN AND
WRN HIGH TERRAIN...TO THE MID 60S IN THE CENTRAL MTNS...AND AROUND
70F IN THE METRO AREAS OF THE LOWER SUSQ VALLEY.
&&
.SHORT TERM /8 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
APPROACHING SHORTWAVE AND ASSOC SFC COLD FRONT WILL BRING A
CHANCE OF MAINLY AFTERNOON AND EVENING SHRA/TSRA WEDNESDAY.
HIGHEST /LIKELY/ POPS ARE PAINTED ACROSS THE NW MTNS CLOSEST TO
APPROACHING COLD FRONT. ALL SHORT RANGE MDLS INDICATE THERE WILL
BE A MINIMUM IN SHOWER ACTIVITY ACROSS THE CENTRAL MTNS IN
CONJUNCTION WITH LINGERING RIBBON OF LOWER PWATS.
PARTLY-MOSTLY CLOUDY SKIES AND SCT PM CONVECTION MAY HOLD TEMPS
DOWN A BIT FROM RECENT DAYS. HOWEVER...THE AIR MASS REMAINS VERY
WARM WITH MDL 8H TEMPS AOA 18C. EXPECT TEMPS TO TOP OUT WELL INTO
THE 80S AGAIN...WITH 90F STILL POSSIBLE ACROSS THE SUSQ VALLEY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
LITTLE CHANGE IN MEDIUM RANGE MODELS AND EFS TODAY AS TRANSITION
FROM HOT AND DRY SUMMERTIME CONDITIONS PERSISTS LATER THIS WEEK
INTO THIS WEEKEND.
WHILE LEADING SHORTWAVE NUDGES AND DISPLACES RIDGE SLIGHTLY AT
MIDWEEK...TRAILING SLOW- MOVING COLD FRONT PASSES THROUGH
PENNSYLVANIA LATE WEDNESDAY NIGHT INTO THURSDAY WHILE DEEP UPPER
TROF SLOWLY PROPOGATES THROUGH THE GREAT LAKES AND THE OHIO VALLEY
THURSDAY AND FRIDAY. BENEFICIAL RAINFALL EXPECTED FROM THIS SLOW
MOVING SYSTEM...AND SHOWERS WILL LIKELY LINGER OVER SOUTHEAST PA
ON THURSDAY BEFORE EXITING THE EASTERN SEABOARD THU NIGHT. AFTER
A FAIR DAY FRIDAY...MOISTURE SHOULD INCREASE AGAIN THROUGHOUT THE
DAY SATURDAY AS DEEP UPPER TROF ARRIVES FROM THE OHIO VALLEY.
MODELS AND EFS CREATE OHIO VALLEY CUTOFF LOW WHICH WILL KEEP
SHOWERY CONDITIONS OVER THE REGION FOR THE REST OF THE WEEKEND
BEFORE DRYING ARRIVES TO START THE WEEK...AND HIGH PRESSURE BUILDS
OVER THE MIDDLE APPALACHIANS TO THE MID ATLANTIC COAST MON-TUE.
THIS WILL ALLOW TEMPS TO REBOUND AFTER A BRIEF DIP SAT-SUN
ASSOCIATED WITH THE AFOREMENTIONED CUTOFF.
&&
.AVIATION /04Z WEDNESDAY THROUGH SUNDAY/...
03Z TAFS SENT.
EARLIER DISCUSSION BELOW.
STILL A FEW LOW...MID...AND HIGH CLDS AROUND.
MAINLY LOOKING AT VFR CONDITIONS TONIGHT INTO WED.
SOME FOG POSSIBLE AT BFD FOR AN HOUR OR SO LATE TONIGHT.
LIKEWISE SOME POSSIBLE AT LNS. EXPECT IPT TO HAVE SOME
FOG LATE...ALONG WITH A LOW CIG.
ALL THIS BASED ON A MIX OF GUIDANCE AND WHAT HAPPEN LAST NIGHT.
LIMITING FACTOR TONIGHT WILL BE A LITTLE MORE OF A SW BREEZE...AS
THE GRADIENT PICKS UP. THIS BEING THE RESULT OF THE LOW TRACKING
NE ACROSS THE CENTRAL GREAT LAKES. ALSO DEWPOINTS THIS AFTERNOON
HAVE BEEN ON THE DECREASE.
THERE COULD BE A SHOWER OR TWO AT BFD ON WED...BUT HARD TO SEE
MUCH GOING ON...THUS JUST WENT WITH VCSH AT BFD.
00Z TAFS SENT.
A COLD FRONT WILL DRIFT SLOWLY EAST FROM THE GREAT LAKES AND
CROSS THE REGION LATE WEDNESDAY AFTERNOON AND WED NIGHT. MAIN CHC
FOR SHOWERS WILL BE ACROSS THE WRN MTNS OF PA...COINCIDING WITH
PEAK HEATING CLOSE TO THE TIME OF THE CFROPA. CHC FOR SHOWERS WILL
DIMINISH ACROSS THE ERN HALF OF PA.
OUTLOOK...
THU...MORE NUMEROUS SHRA/TSRA EXPECTED. BRIEF IFR CIGS AND VSBYS
POSSIBLE.
FRI...PATCHY MORNING FOG POSSIBLE...OTHERWISE GENERALLY VFR.
SAT...SCATTERED SHRA/TSRA.
SUN...SCATTERED SHOWERS...MAINLY EASTERN AREAS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...DANGELO/LAMBERT
SHORT TERM...FITZGERALD/LAMBERT
LONG TERM...DEVOIR/FITZGERALD/CERU
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
826 PM EDT TUE SEP 8 2015
.SYNOPSIS...
HIGH PRESSURE THAT BROUGHT US THIS RECENT STRING OF DRY AND VERY
WARM DAYS WILL DRIFT OFF THE EAST COAST. A COLD FRONT WILL MOVE
SLOWLY EAST ACROSS THE REGION WEDNESDAY AFTERNOON AND NIGHT. A
WAVE OF LOW PRESSURE WILL FORM ALONG THIS FRONT AND BRING A
SHOWERY AND MUCH COOLER DAY FOR THURSDAY. MAINLY DRY AND
SEASONABLY COOL CONDITIONS WILL FOLLOW FOR LATER THURSDAY NIGHT
THROUGH FRIDAY. A DEEP TROUGH WILL FORM OVER THE OHIO AND
TENNESSEE VALLEYS SATURDAY...THEN MOVE SLOWLY TO THE NORTHEAST
SUNDAY AND MONDAY BRINGING THE POTENTIAL FOR LOCALLY HEAVY RAIN.
&&
.NEAR TERM /UNTIL 7 AM WEDNESDAY MORNING/...
8 PM UPDATE...
CLOUDS NOT GOING AWAY ALONG THE ALLEGHENY FRONT AND ARE EVEN
DEVELOPING/GROWING SLIGHTLY. SPECKLES OF REFLECTIVITY ARE STARTING
TO SHOW UP ON RADAR AS WELL...EVEN NEAR KMDT. NAM AND HRRR HAS
THIS - PERHAPS OVER DOING IT - GENERATING SOME QPF OVER MOST OF
THOSE HIGHER ELEVATIONS IN THE ALLEGHENIES OVER THE NEXT 3-4HRS.
THE LOW/MID LEVEL FLOW IS INCREASING SLIGHTLY AND COULD BE RUNNING
INTO LIGHTER FLOW OUT OF THE SOUTHWEST. THE WINDS THEN BECOME
MORE- ALIGNED IN THE LOWEST 10KFT LATER TONIGHT. LOWEST CLOUD DECK
IS ABOUT 8KFT...SO WILL COUNT ON ANY RAIN FALLING FROM THEM TO
MOSTLY DRY UP BEFORE IT GETS TO THE GROUND. STILL...A VERY LIGHT
SHOWER IS POSSIBLE THERE FOR THE NEXT FEW HOURS.
FROM PREV...
SOME OF THE HIGHEST TERRAIN ACROSS THE WEST COULD SEE THE SW WIND
STAY UP AT AROUND 5-8 KTS TONIGHT AS THE LLVL P-GRADIENT TIGHTENS
A BIT.
LOW TEMPS TONIGHT WILL VARY FROM THE LOWER 60S ACROSS THE NRN AND
WRN HIGH TERRAIN...TO THE MID 60S IN THE CENTRAL MTNS...AND AROUND
70F IN THE METRO AREAS OF THE LOWER SUSQ VALLEY.
&&
.SHORT TERM /7 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
APPROACHING SHORTWAVE AND ASSOC SFC COLD FRONT WILL BRING A
CHANCE OF MAINLY AFTERNOON AND EVENING SHRA/TSRA WEDNESDAY.
HIGHEST /LIKELY/ POPS ARE PAINTED ACROSS THE NW MTNS CLOSEST TO
APPROACHING COLD FRONT. ALL SHORT RANGE MDLS INDICATE THERE WILL
BE A MINIMUM IN SHOWER ACTIVITY ACROSS THE CENTRAL MTNS IN
CONJUNCTION WITH LINGERING RIBBON OF LOWER PWATS.
PARTLY-MOSTLY CLOUDY SKIES AND SCT PM CONVECTION MAY HOLD TEMPS
DOWN A BIT FROM RECENT DAYS. HOWEVER...THE AIR MASS REMAINS VERY
WARM WITH MDL 8H TEMPS AOA 18C. EXPECT TEMPS TO TOP OUT WELL INTO
THE 80S AGAIN...WITH 90F STILL POSSIBLE ACROSS THE SUSQ VALLEY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
LITTLE CHANGE IN MEDIUM RANGE MODELS AND EFS TODAY AS TRANSITION
FROM HOT AND DRY SUMMERTIME CONDITIONS PERSISTS LATER THIS WEEK
INTO THIS WEEKEND.
WHILE LEADING SHORTWAVE NUDGES AND DISPLACES RIDGE SLIGHTLY AT
MIDWEEK...TRAILING SLOW- MOVING COLD FRONT PASSES THROUGH
PENNSYLVANIA LATE WEDNESDAY NIGHT INTO THURSDAY WHILE DEEP UPPER
TROF SLOWLY PROPOGATES THROUGH THE GREAT LAKES AND THE OHIO VALLEY
THURSDAY AND FRIDAY. BENEFICIAL RAINFALL EXPECTED FROM THIS SLOW
MOVING SYSTEM...AND SHOWERS WILL LIKELY LINGER OVER SOUTHEAST PA
ON THURSDAY BEFORE EXITING THE EASTERN SEABOARD THU NIGHT. AFTER
A FAIR DAY FRIDAY...MOISTURE SHOULD INCREASE AGAIN THROUGHOUT THE
DAY SATURDAY AS DEEP UPPER TROF ARRIVES FROM THE OHIO VALLEY.
MODELS AND EFS CREATE OHIO VALLEY CUTOFF LOW WHICH WILL KEEP
SHOWERY CONDITIONS OVER THE REGION FOR THE REST OF THE WEEKEND
BEFORE DRYING ARRIVES TO START THE WEEK...AND HIGH PRESSURE BUILDS
OVER THE MIDDLE APPALACHIANS TO THE MID ATLANTIC COAST MON-TUE.
THIS WILL ALLOW TEMPS TO REBOUND AFTER A BRIEF DIP SAT-SUN
ASSOCIATED WITH THE AFOREMENTIONED CUTOFF.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
STILL A FEW LOW...MID...AND HIGH CLDS AROUND.
MAINLY LOOKING AT VFR CONDITIONS TONIGHT INTO WED.
SOME FOG POSSIBLE AT BFD FOR AN HOUR OR SO LATE TONIGHT.
LIKEWISE SOME POSSIBLE AT LNS. EXPECT IPT TO HAVE SOME
FOG LATE...ALONG WITH A LOW CIG.
ALL THIS BASED ON A MIX OF GUIDANCE AND WHAT HAPPEN LAST NIGHT.
LIMITING FACTOR TONIGHT WILL BE A LITTLE MORE OF A SW BREEZE...AS
THE GRADIENT PICKS UP. THIS BEING THE RESULT OF THE LOW TRACKING
NE ACROSS THE CENTRAL GREAT LAKES. ALSO DEWPOINTS THIS AFTERNOON
HAVE BEEN ON THE DECREASE.
THERE COULD BE A SHOWER OR TWO AT BFD ON WED...BUT HARD TO SEE
MUCH GOING ON...THUS JUST WENT WITH VCSH AT BFD.
00Z TAFS SENT.
A COLD FRONT WILL DRIFT SLOWLY EAST FROM THE GREAT LAKES AND
CROSS THE REGION LATE WEDNESDAY AFTERNOON AND WED NIGHT. MAIN CHC
FOR SHOWERS WILL BE ACROSS THE WRN MTNS OF PA...COINCIDING WITH
PEAK HEATING CLOSE TO THE TIME OF THE CFROPA. CHC FOR SHOWERS WILL
DIMINISH ACROSS THE ERN HALF OF PA.
OUTLOOK...
THU...MORE NUMEROUS SHRA/TSRA EXPECTED. BRIEF IFR CIGS AND VSBYS
POSSIBLE.
FRI...PATCHY MORNING FOG POSSIBLE...OTHERWISE GENERALLY VFR.
SAT...SCATTERED SHRA/TSRA.
SUN...SCATTERED SHOWERS...MAINLY EASTERN AREAS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...DANGELO/LAMBERT
SHORT TERM...FITZGERALD/LAMBERT
LONG TERM...DEVOIR/FITZGERALD/CERU
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
131 PM CDT MON SEP 7 2015
.AVIATION UPDATE...
ISOLATED STORMS AGAIN POSSIBLE THIS AFTERNOON EAST.
ADDITIONALLY...PATCHY MVFR FOG AGAIN EXPECTED TO
DEVELOP OVERNIGHT. VFR CONDITIONS LIKELY OTHERWISE
WITH WIND SPEEDS NEAR OR LESS THAN 6KNTS.
&&
.PREV DISCUSSION... /ISSUED 632 AM CDT MON SEP 7 2015/
UPDATE...
FOR 12Z AVIATION.
DISCUSSION...
LATEST SURFACE OBSERVATIONS SHOWS TEMPERATURES IN THE 60S TO LOW
70S ACROSS THE MID STATE WITH DEWPOINTS ALSO IN THE 60S UNDER
NEARLY CLEAR SKIES. SEVERAL OBS ALSO SHOWING PATCHY FOG ALTHOUGH
NO DENSE FOG HAS BEEN NOTED THUS FAR. WILL KEEP MENTION OF PATCHY
FOG IN THE GRIDS/ZONES THROUGH 14Z. OTHERWISE...ANOTHER HOT AND
HUMID DAY IS ON TAP WITH TEMPERATURES RISING INTO THE 80S PLATEAU
AND LOW 90S ELSEWHERE...SIMILAR TO YESTERDAY. WATER VAPOR IMAGERY
DEPICTS AN UPPER LEVEL LOW CENTERED OVER GEORGIA...WITH DRY AIR ON
THE WEST SIDE OF THE LOW CURRENTLY ACROSS THE MID STATE. 00Z
GFS/ECMWF SLOWLY RETROGRADE THIS LOW TO THE SOUTHWEST OVER THE
NEXT FEW DAYS WHILE MOISTURE ADVECTS WESTWARD AROUND THE NORTH
SIDE OF THE LOW INTO MIDDLE TENNESSEE. THUS EXPECTING ISOLATED
SHOWERS AND STORMS AGAIN TODAY...BUT MAINLY TO THE EAST OF I-65 AS
THE DRY AIR ALOFT LIMITS COVERAGE OVER WESTERN ZONES. THIS
THINKING IS IN LINE WITH THE LATEST HRRR MODEL RUNS WHICH KEEPS
CONVECTION MAINLY OVER THE EASTERN HALF OF THE CWA.
POPS WILL INCREASE WESTWARD ON TUESDAY AS PWATS RISE BACK ABOVE
1.5 INCHES ACROSS MUCH OF THE FORECAST AREA. BY WEDNESDAY...THE
MAIN BELT OF WESTERLIES ACROSS THE NORTHERN CONUS BEGINS TO SINK
SOUTHWARD ACROSS THE TENNESSEE VALLEY...WITH A COLD FRONT PROGGED
TO MOVE ACROSS THE FORECAST AREA ON THURSDAY. THE INCREASE IN
UPPER LEVEL SUPPORT ALONG WITH PWATS RISING TO AROUND 1.75 INCHES
AND THE FRONTAL FOCUS ALL INDICATE FAIRLY WIDESPREAD SHOWERS AND
STORMS WEDNESDAY INTO THURSDAY...WARRANTING CHANCE TO LIKELY POPS
ALONG WITH MUCH COOLER HIGH TEMPS DUE TO PRECIP/CLOUD COVER. 00Z
GFS/ECMWF INDICATE AREA WILL DRY OUT ON FRIDAY...BUT A FEW SHOWERS
ARE POSSIBLE FRIDAY NIGHT AND SATURDAY AS A SECONDARY SURGE OF
COOLER AIR MOVES ACROSS. VERY PLEASANT FALL-LIKE CONDITIONS ARE
ANTICIPATED SATURDAY AND SUNDAY WITH LOW HUMIDITY AND
TEMPERATURES SEVERAL DEGREES BELOW NORMAL FOR THIS TIME OF YEAR.
AVIATION...
12Z TAF DISCUSSION.
MVFR TO LIFR FOG HAS OCCURRED AT KCKV AND KCSV THIS MORNING...AND
COULD CONTINUE UNTIL AROUND 14Z OR SO. OTHERWISE EXPECT VFR
CONDITIONS TO CONTINUE THROUGH THE DAY. FOG MAY AGAIN RETURN
TONIGHT AND INTO THE EARLY MORNING TOMORROW. WINDS WILL BE LIGHT
AND MAINLY OUT OF THE SOUTHEAST TODAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 70 90 72 87 / 0 20 10 40
CLARKSVILLE 68 90 70 87 / 0 10 0 30
CROSSVILLE 66 83 68 80 / 10 20 20 50
COLUMBIA 68 89 70 87 / 0 20 10 40
LAWRENCEBURG 68 86 70 86 / 0 20 20 40
WAVERLY 69 89 70 86 / 0 10 10 30
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1213 PM CDT MON SEP 7 2015
.UPDATE...
UPDATED FOR 18Z AVIATION DISCUSSION...
&&
.PREV DISCUSSION... /ISSUED 1003 AM CDT MON SEP 7 2015/
UPDATE...
ANOTHER HOT AND HUMID DAY IS UPCOMING FOR THE MIDSOUTH.
TEMPERATURES ARE ALREADY IN THE LOW TO MID 80S AS OF 10AM. ONCE
AGAIN THE HRRR IS OVERDOING AFTERNOON THUNDERSTORM COVERAGE.
EXPECT COVERAGE TO BE MINIMAL AT BEST. HIGHS TODAY WILL REACH THE
MID 90S WITH HEAT INDICES NEAR 100. NO CHANGES TO THE PREVIOUS
FORECAST WERE NECESSARY.
PREV DISCUSSION... /ISSUED 317 AM CDT MON SEP 7 2015/
DISCUSSION...
THE MID SOUTH WILL REMAIN POSITIONED BETWEEN UPPER LEVEL HIGH
PRESSURE OVER THE SOUTHERN PLAINS AND AN UPPER LEVEL LOW PRESSURE
SYSTEM OVER GEORGIA TODAY. THIS WILL ALLOW FOR THE CONTINUATION OF
DRY...HOT...AND HUMID CONDITIONS. THE UPPER LOW WILL MOVE
SOUTHWESTWARD THROUGH TUESDAY AND SHOULD SPREAD ISOLATED SHOWERS
AND THUNDERSTORMS INTO PORTIONS OF WEST TENNESSEE NEAR THE
TENNESSEE RIVER AND NORTHEAST MISSISSIPPI BY TUESDAY AFTERNOON.
ELSEWHERE...DRY AND HOT WEATHER WILL CONTINUE ALONG WITH HUMID
CONDITIONS.
THE UPPER LEVEL RIDGE EXTENDING OVER THE AREA EARLY IN THE WEEK
WILL BREAK DOWN BY WEDNESDAY AS A SHORTWAVE TROUGH DIGS ACROSS THE
CENTRAL PLAINS INTO THE LOWER MISSISSIPPI VALLEY. THIS SHOULD
INCREASE CHANCES FOR SHOWERS AND THUNDERSTORMS ACROSS THE AREA AND
KNOCK TEMPERATURES BACK DOWN TO NEAR NORMAL LEVELS FOR THIS TIME
OF YEAR. THE UPPER LEVEL TROUGH SHOULD REMAIN OVER THE REGION
INTO THURSDAY WITH CONTINUED CHANCES FOR SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS.
A STRONGER SHORTWAVE WILL DIVE SOUTHEAST INTO THE REGION ON FRIDAY
AND HELP TO PUSH A COLD FRONT SOUTH ACROSS THE FORECAST AREA.
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL AGAIN BE
POSSIBLE ON FRIDAY AS THE FRONT MOVES THROUGH. SURFACE HIGH
PRESSURE SHOULD BUILD INTO THE AREA AS UPPER LEVEL TROUGHING
REMAINS OVER THE EASTERN HALF OF THE NATION. DRY WEATHER ALONG
WITH COOLER AND LESS HUMID CONDITIONS CAN BE EXPECTED FOR NEXT
WEEKEND.
BY EARLY NEXT WEEK...ATTENTION WILL TURN TO THE WESTERN GULF OF
MEXICO WHERE MODELS ARE HINTING AT POTENTIAL TROPICAL
DEVELOPMENT. LATEST GUIDANCE BRINGS ANY DEVELOPING SYSTEM NORTH
THROUGH THE ARKLATEX AND INTO OUR REGION EARLY NEXT WEEK. PLAN TO
CARRY AN INCREASE IN RAIN CHANCES EARLY NEXT WEEK...BUT WILL NOT
GO AS HIGH AS CURRENT GUIDANCE UNTIL THIS SOLUTION LOOKS MORE
LIKELY. THIS SCENARIO WILL BE WATCHED CLOSELY OVER THE NEXT
SEVERAL DAYS.
JLH
.AVIATION...
12Z TAF CYCLE
VFR CONDITIONS ARE EXPECTED THROUGH THE NEXT 24 HOURS. PATCHY FOG
IS ONCE AGAIN POSSIBLE TONIGHT AT MKL...JBR AND TUP BUT SHOULD
BURN OFF BY 13Z ON TUESDAY.
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1003 AM CDT MON SEP 7 2015
.UPDATE...
ANOTHER HOT AND HUMID DAY IS UPCOMING FOR THE MIDSOUTH.
TEMPERATURES ARE ALREADY IN THE LOW TO MID 80S AS OF 10AM. ONCE
AGAIN THE HRRR IS OVERDOING AFTERNOON THUNDERSTORM COVERAGE.
EXPECT COVERAGE TO BE MINIMAL AT BEST. HIGHS TODAY WILL REACH THE
MID 90S WITH HEAT INDICES NEAR 100. NO CHANGES TO THE PREVIOUS
FORECAST WERE NECESSARY.
&&
.PREV DISCUSSION... /ISSUED 608 AM CDT MON SEP 7 2015/
UPDATE...
UPDATED TO ADD 12Z AVIATION DISCUSSION.
PREV DISCUSSION... /ISSUED 317 AM CDT MON SEP 7 2015/
DISCUSSION...
THE MID SOUTH WILL REMAIN POSITIONED BETWEEN UPPER LEVEL HIGH
PRESSURE OVER THE SOUTHERN PLAINS AND AN UPPER LEVEL LOW PRESSURE
SYSTEM OVER GEORGIA TODAY. THIS WILL ALLOW FOR THE CONTINUATION OF
DRY...HOT...AND HUMID CONDITIONS. THE UPPER LOW WILL MOVE
SOUTHWESTWARD THROUGH TUESDAY AND SHOULD SPREAD ISOLATED SHOWERS
AND THUNDERSTORMS INTO PORTIONS OF WEST TENNESSEE NEAR THE
TENNESSEE RIVER AND NORTHEAST MISSISSIPPI BY TUESDAY AFTERNOON.
ELSEWHERE...DRY AND HOT WEATHER WILL CONTINUE ALONG WITH HUMID
CONDITIONS.
THE UPPER LEVEL RIDGE EXTENDING OVER THE AREA EARLY IN THE WEEK
WILL BREAK DOWN BY WEDNESDAY AS A SHORTWAVE TROUGH DIGS ACROSS THE
CENTRAL PLAINS INTO THE LOWER MISSISSIPPI VALLEY. THIS SHOULD
INCREASE CHANCES FOR SHOWERS AND THUNDERSTORMS ACROSS THE AREA AND
KNOCK TEMPERATURES BACK DOWN TO NEAR NORMAL LEVELS FOR THIS TIME
OF YEAR. THE UPPER LEVEL TROUGH SHOULD REMAIN OVER THE REGION
INTO THURSDAY WITH CONTINUED CHANCES FOR SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS.
A STRONGER SHORTWAVE WILL DIVE SOUTHEAST INTO THE REGION ON FRIDAY
AND HELP TO PUSH A COLD FRONT SOUTH ACROSS THE FORECAST AREA.
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL AGAIN BE
POSSIBLE ON FRIDAY AS THE FRONT MOVES THROUGH. SURFACE HIGH
PRESSURE SHOULD BUILD INTO THE AREA AS UPPER LEVEL TROUGHING
REMAINS OVER THE EASTERN HALF OF THE NATION. DRY WEATHER ALONG
WITH COOLER AND LESS HUMID CONDITIONS CAN BE EXPECTED FOR NEXT
WEEKEND.
BY EARLY NEXT WEEK...ATTENTION WILL TURN TO THE WESTERN GULF OF
MEXICO WHERE MODELS ARE HINTING AT POTENTIAL TROPICAL
DEVELOPMENT. LATEST GUIDANCE BRINGS ANY DEVELOPING SYSTEM NORTH
THROUGH THE ARKLATEX AND INTO OUR REGION EARLY NEXT WEEK. PLAN TO
CARRY AN INCREASE IN RAIN CHANCES EARLY NEXT WEEK...BUT WILL NOT
GO AS HIGH AS CURRENT GUIDANCE UNTIL THIS SOLUTION LOOKS MORE
LIKELY. THIS SCENARIO WILL BE WATCHED CLOSELY OVER THE NEXT
SEVERAL DAYS.
JLH
.AVIATION...
12Z TAF CYCLE
PATCHY FOG MAY PRODUCE TEMPORARY MVFR/IFR VISIBILITIES AT MKL/JBR
THROUGH 07/13Z AND AGAIN LATE TONIGHT AT MKL/JBR/TUP.
OTHERWISE...VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THE PERIOD.
LIGHT WINDS WILL BECOME SE WINDS BETWEEN 5-8 KTS AFTER 07/15Z.
CJC
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
632 AM CDT MON SEP 7 2015
.UPDATE...
FOR 12Z AVIATION.
&&
.DISCUSSION...
LATEST SURFACE OBSERVATIONS SHOWS TEMPERATURES IN THE 60S TO LOW
70S ACROSS THE MID STATE WITH DEWPOINTS ALSO IN THE 60S UNDER
NEARLY CLEAR SKIES. SEVERAL OBS ALSO SHOWING PATCHY FOG ALTHOUGH
NO DENSE FOG HAS BEEN NOTED THUS FAR. WILL KEEP MENTION OF PATCHY
FOG IN THE GRIDS/ZONES THROUGH 14Z. OTHERWISE...ANOTHER HOT AND
HUMID DAY IS ON TAP WITH TEMPERATURES RISING INTO THE 80S PLATEAU
AND LOW 90S ELSEWHERE...SIMILAR TO YESTERDAY. WATER VAPOR IMAGERY
DEPICTS AN UPPER LEVEL LOW CENTERED OVER GEORGIA...WITH DRY AIR ON
THE WEST SIDE OF THE LOW CURRENTLY ACROSS THE MID STATE. 00Z
GFS/ECMWF SLOWLY RETROGRADE THIS LOW TO THE SOUTHWEST OVER THE
NEXT FEW DAYS WHILE MOISTURE ADVECTS WESTWARD AROUND THE NORTH
SIDE OF THE LOW INTO MIDDLE TENNESSEE. THUS EXPECTING ISOLATED
SHOWERS AND STORMS AGAIN TODAY...BUT MAINLY TO THE EAST OF I-65 AS
THE DRY AIR ALOFT LIMITS COVERAGE OVER WESTERN ZONES. THIS
THINKING IS IN LINE WITH THE LATEST HRRR MODEL RUNS WHICH KEEPS
CONVECTION MAINLY OVER THE EASTERN HALF OF THE CWA.
POPS WILL INCREASE WESTWARD ON TUESDAY AS PWATS RISE BACK ABOVE
1.5 INCHES ACROSS MUCH OF THE FORECAST AREA. BY WEDNESDAY...THE
MAIN BELT OF WESTERLIES ACROSS THE NORTHERN CONUS BEGINS TO SINK
SOUTHWARD ACROSS THE TENNESSEE VALLEY...WITH A COLD FRONT PROGGED
TO MOVE ACROSS THE FORECAST AREA ON THURSDAY. THE INCREASE IN
UPPER LEVEL SUPPORT ALONG WITH PWATS RISING TO AROUND 1.75 INCHES
AND THE FRONTAL FOCUS ALL INDICATE FAIRLY WIDESPREAD SHOWERS AND
STORMS WEDNESDAY INTO THURSDAY...WARRANTING CHANCE TO LIKELY POPS
ALONG WITH MUCH COOLER HIGH TEMPS DUE TO PRECIP/CLOUD COVER. 00Z
GFS/ECMWF INDICATE AREA WILL DRY OUT ON FRIDAY...BUT A FEW SHOWERS
ARE POSSIBLE FRIDAY NIGHT AND SATURDAY AS A SECONDARY SURGE OF
COOLER AIR MOVES ACROSS. VERY PLEASANT FALL-LIKE CONDITIONS ARE
ANTICIPATED SATURDAY AND SUNDAY WITH LOW HUMIDITY AND
TEMPERATURES SEVERAL DEGREES BELOW NORMAL FOR THIS TIME OF YEAR.
&&
.AVIATION...
12Z TAF DISCUSSION.
MVFR TO LIFR FOG HAS OCCURRED AT KCKV AND KCSV THIS MORNING...AND
COULD CONTINUE UNTIL AROUND 14Z OR SO. OTHERWISE EXPECT VFR
CONDITIONS TO CONTINUE THROUGH THE DAY. FOG MAY AGAIN RETURN
TONIGHT AND INTO THE EARLY MORNING TOMORROW. WINDS WILL BE LIGHT
AND MAINLY OUT OF THE SOUTHEAST TODAY.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
06
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
319 AM CDT MON SEP 7 2015
.DISCUSSION...
LATEST SURFACE OBSERVATIONS SHOWS TEMPERATURES IN THE 60S TO LOW
70S ACROSS THE MID STATE WITH DEWPOINTS ALSO IN THE 60S UNDER
NEARLY CLEAR SKIES. SEVERAL OBS ALSO SHOWING PATCHY FOG ALTHOUGH
NO DENSE FOG HAS BEEN NOTED THUS FAR. WILL KEEP MENTION OF PATCHY
FOG IN THE GRIDS/ZONES THROUGH 14Z. OTHERWISE...ANOTHER HOT AND
HUMID DAY IS ON TAP WITH TEMPERATURES RISING INTO THE 80S PLATEAU
AND LOW 90S ELSEWHERE...SIMILAR TO YESTERDAY. WATER VAPOR IMAGERY
DEPICTS AN UPPER LEVEL LOW CENTERED OVER GEORGIA...WITH DRY AIR ON
THE WEST SIDE OF THE LOW CURRENTLY ACROSS THE MID STATE. 00Z
GFS/ECMWF SLOWLY RETROGRADE THIS LOW TO THE SOUTHWEST OVER THE
NEXT FEW DAYS WHILE MOISTURE ADVECTS WESTWARD AROUND THE NORTH
SIDE OF THE LOW INTO MIDDLE TENNESSEE. THUS EXPECTING ISOLATED
SHOWERS AND STORMS AGAIN TODAY...BUT MAINLY TO THE EAST OF I-65 AS
THE DRY AIR ALOFT LIMITS COVERAGE OVER WESTERN ZONES. THIS
THINKING IS IN LINE WITH THE LATEST HRRR MODEL RUNS WHICH KEEPS
CONVECTION MAINLY OVER THE EASTERN HALF OF THE CWA.
POPS WILL INCREASE WESTWARD ON TUESDAY AS PWATS RISE BACK ABOVE
1.5 INCHES ACROSS MUCH OF THE FORECAST AREA. BY WEDNESDAY...THE
MAIN BELT OF WESTERLIES ACROSS THE NORTHERN CONUS BEGINS TO SINK
SOUTHWARD ACROSS THE TENNESSEE VALLEY...WITH A COLD FRONT PROGGED
TO MOVE ACROSS THE FORECAST AREA ON THURSDAY. THE INCREASE IN
UPPER LEVEL SUPPORT ALONG WITH PWATS RISING TO AROUND 1.75 INCHES
AND THE FRONTAL FOCUS ALL INDICATE FAIRLY WIDESPREAD SHOWERS AND
STORMS WEDNESDAY INTO THURSDAY...WARRANTING CHANCE TO LIKELY POPS
ALONG WITH MUCH COOLER HIGH TEMPS DUE TO PRECIP/CLOUD COVER. 00Z
GFS/ECMWF INDICATE AREA WILL DRY OUT ON FRIDAY...BUT A FEW SHOWERS
ARE POSSIBLE FRIDAY NIGHT AND SATURDAY AS A SECONDARY SURGE OF
COOLER AIR MOVES ACROSS. VERY PLEASANT FALL-LIKE CONDITIONS ARE
ANTICIPATED SATURDAY AND SUNDAY WITH LOW HUMIDITY AND
TEMPERATURES SEVERAL DEGREES BELOW NORMAL FOR THIS TIME OF YEAR.
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 92 70 92 71 / 20 0 20 10
CLARKSVILLE 93 67 92 69 / 10 0 10 0
CROSSVILLE 84 65 84 67 / 20 10 20 20
COLUMBIA 91 67 91 69 / 10 0 20 10
LAWRENCEBURG 89 68 89 69 / 10 0 20 20
WAVERLY 91 67 92 69 / 10 0 10 10
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHAMBURGER
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1045 PM CDT TUE SEP 8 2015
.AVIATION...
NO REAL CHANGES FROM FORECAST OF SIX HOURS AGO. UNEVENTFUL WEATHER
EXPECTED TONIGHT UNTIL ONSET OF FOG AND LOW CLOUDS BETWEEN 11Z AND
15Z WEDNESDAY. EXPECT RAPID CLEARING WITH GENERALLY CLEAR SKY
DURING MOST OF DAYTIME HOURS AND WEDNESDAY EVENING. SURFACE WINDS
EXPECTED TO VEER TO SOUTHEAST BY WEDNESDAY AFTERNOON.
COCKRELL
&&
.PREV DISCUSSION... /ISSUED 939 PM CDT TUE SEP 8 2015/
UPDATE...
HAVE UPDATED GRAPHICAL FORECASTS...ELIMINATING OR LOWERING POPS
SUBSTANTIALLY FOR TONIGHT. RADAR TRENDS SUGGEST LITTLE ADDITIONAL
THUNDERSTORM DEVELOPMENT IS LIKELY FOR MOST OF THE AREA. UPDATED
TEXT PRODUCTS WILL BE ISSUED SHORTLY.
COCKRELL
PREV DISCUSSION... /ISSUED 640 PM CDT TUE SEP 8 2015/
AVIATION...
COLD FRONT HAS CLEARED ALL OF FORECAST AREA...WITH NO THUNDERSTORMS
EXPECTED AT TERMINALS THIS EVENING OR OVERNIGHT. WILL CONTINUE TO
MONITOR CONVECTION IN NORTHEASTERN NEW MEXICO IN CASE THOSE SHOWERS
AND THUNDERSTORMS POSE A THREAT TO KDHT.
LIGHT NORTHEAST SURFACE WINDS EXPECTED TO PREVAIL TONIGHT...WITH
POTENTIAL FOR FOG AND STRATUS TO DEVELOP WEDNESDAY MORNING. FOR
NOW...WILL FORECAST PREVAILING VFR VISIBILITIES AND SKY...WITH
OCCASIONAL MVFR VISIBILITIES AND IFR CEILINGS BETWEEN 11Z AND 15Z
WEDNESDAY.
VFR CONDITIONS EXPECTED TO PREVAIL THEREAFTER AS SURFACE WINDS VEER
TO EAST AND SOUTHEAST DURING THE DAY BELOW A GENERALLY CLEAR SKY.
COCKRELL
PREV DISCUSSION... /ISSUED 242 PM CDT TUE SEP 8 2015/
DISCUSSION...
LATEST SURFACE OBS SHOWS THE COLD FRONT EXTENDING FROM JUST NORTH OF
WHEELER SOUTHWESTWARD TO NEAR CLAUDE. MORNING SOUNDING INDICATES
CONSIDERABLE MOISTENING IN THE MID LEVELS AS EVIDENT BY WIDESPREAD
ALTOSTRATUS OBSERVED ACROSS MOST OF THE AREA. POST FRONTAL AIR MASS
IS RELATIVELY COOL ESPECIALLY WHERE MID CLOUDS ARE MOST EXTENSIVE.
TEMPERATURES AT 19Z RANGE FROM THE MID 70S TO THE MID 80S BEHIND THE
FRONT. DESPITE MOIST ADVECTION BEHIND THE FRONT IN THE
NORTHEAST...DIABATIC HEATING HAS BEEN INSUFFICIENT FOR MEANINGFUL
INSTABILITY TO DEVELOP. TEMPERATURES WERE NEAR 100 DEGREES IN THE
FAR SOUTHEAST WHERE SOUTHWESTERLY SURFACE WINDS PREVAIL AND CLOUD
COVER HAS BEEN LIMITED. THIS IS WHERE INSTABILITY HAS INCREASED THE
MOST AND GIVEN LOW/MID 60 DEGREE DEW POINTS MODERATE INSTABILITY HAS
DEVELOPED DESPITE WEAK MID LEVEL LAPSE RATES. SO FAR CONVECTION HAS
BEEN RELATIVELY BENIGN AND CONFINED MOSTLY TO ALONG AND JUST BEHIND
THE FRONT ACROSS EAST CENTRAL AND NORTHEAST PORTIONS OF THE TEXAS
PANHANDLE. SOME INTENSIFICATION SHOULD OCCUR LATER THIS AFTERNOON BUT
CHANCES WILL DECREASE FAIRLY QUICKLY LATER THIS AFTERNOON AND
ESPECIALLY BY EVENING AS LIFT ASSOCIATED WITH A WEAK SHORTWAVE SHIFTS
EASTWARD INTO OKLAHOMA. THIS SHORTWAVE IS DIFFICULT TO SEE BUT SOME
INDICATION IN WATER VAPOR IMAGERY AND RAP PV ANALYSIS SUPPORTS TRENDS
SEEN ON RADAR.
MODERATE INSTABILITY IN THE SOUTHEAST AND EAST CENTRAL TEXAS
PANHANDLE RAISES SOME CONCERN FOR SEVERE POTENTIAL. A MISALIGNMENT
OF BEST SHEAR BEHIND THE FRONT (WHERE NORTHERLY/NORTHEASTERLY FLOW
EXISTS) FROM THE MOST SIGNIFICANT INSTABILITY SOUTHEAST OF THE FRONT
IS A NEGATIVE FACTOR. WEAKLY ORGANIZED UPDRAFTS IN THE SOUTHEAST PART
OF THE TEXAS PANHANDLE THROUGH THE AFTERNOON INTO THE EARLY EVENING
COULD RESULT IN BRIEF/ISOLATED MARGINALLY SEVERE HAIL OR WIND GUSTS.
LOCALLY HEAVY RAIN WILL BE POSSIBLE GIVEN MODEST STORM MOTIONS AND A
MOIST ENVIRONMENT WITH PWATS AROUND AN INCH AND A HALF.
HAVE SCALED BACK PRECIPITATION PROBABILITIES LATER TONIGHT BASED ON
TRENDS AND AM QUITE CONFIDENT IN A DRY FORECAST FOR TOMORROW. POST
FRONTAL ENVIRONMENT WILL BE COOLER BUT ONLY SLIGHTLY BELOW NORMAL
VALUES FOR EARLY TO MID SEPTEMBER. DURING THE MID WEEK PERIOD BROAD
CYCLONIC FAIRLY SWIFT MID/UPPER FLOW WILL COVER MUCH OF THE NORTHERN
PORTIONS OF THE COUNTRY. OVERALL NOT MUCH CHANGE WAS MADE TO THE
PREVIOUS FORECAST. THE CHALLENGE WILL SHIFT TOWARD RESOLVING FAST
MOVING SHORTWAVE TROUGHS EMBEDDED WITHIN THE LARGER UPPER LOW OVER
EASTERN CANADA THROUGH THE END OF THE WEEK. MODELS BRING THE FIRST
WAVE THROUGH THE CENTRAL PLAINS LATE THURSDAY THROUGH EARLY FRIDAY
FORCING ANOTHER COLD FRONT THROUGH. CONTINUED THE TREND OF
DOWNPLAYING DAYTIME PRECIPITATION CHANCES ACROSS MUCH OF THE REGION
EXPECT THE NORTHERN TEXAS PANHANDLE AND OKLAHOMA PANHANDLE. CHANCES
SPREAD SOUTH THROUGH THE NIGHT. GIVEN BETTER MODEL AGREEMENT WE NOW
HAVE HIGHER CONFIDENCE ON COOLER WEATHER ON FRIDAY BEHIND THE FRONT
WHICH SHOULD PERSIST INTO SATURDAY. TEMPERATURES RETURN TO NEAR
NORMAL LEVELS SUNDAY INTO THE BEGINNING OF NEXT WEEK AS UPPER FLOW
PATTERN AMPLIFIES FURTHER. THE VERY PRONOUNCED WAVE IN THE GFS MODEL
EMBEDDED WITHIN THE NORTH-NORTHWESTERLY FLOW BETWEEN BUILDING RIDGE
IN THE WEST AND DEEPENING TROUGH IN THE EAST THIS WEEKEND IS FURTHER
EAST AND NOT QUITE AS PRONOUNCED. THIS IS MORE IN LINE WITH OTHER
MEDIUM RANGE GUIDANCE AND WAS ENOUGH FOR US TO KEEP THE LATTER
PORTION OF THE EXTENDED DRY FOR NOW.
BRB
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
3/10
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
939 PM CDT TUE SEP 8 2015
.UPDATE...
HAVE UPDATED GRAPHICAL FORECASTS...ELIMINATING OR LOWERING POPS
SUBSTANTIALLY FOR TONIGHT. RADAR TRENDS SUGGEST LITTLE ADDITIONAL
THUNDERSTORM DEVELOPMENT IS LIKELY FOR MOST OF THE AREA. UPDATED
TEXT PRODUCTS WILL BE ISSUED SHORTLY.
COCKRELL
&&
.PREV DISCUSSION... /ISSUED 640 PM CDT TUE SEP 8 2015/
AVIATION...
COLD FRONT HAS CLEARED ALL OF FORECAST AREA...WITH NO THUNDERSTORMS
EXPECTED AT TERMINALS THIS EVENING OR OVERNIGHT. WILL CONTINUE TO
MONITOR CONVECTION IN NORTHEASTERN NEW MEXICO IN CASE THOSE SHOWERS
AND THUNDERSTORMS POSE A THREAT TO KDHT.
LIGHT NORTHEAST SURFACE WINDS EXPECTED TO PREVAIL TONIGHT...WITH
POTENTIAL FOR FOG AND STRATUS TO DEVELOP WEDNESDAY MORNING. FOR
NOW...WILL FORECAST PREVAILING VFR VISIBILITIES AND SKY...WITH
OCCASIONAL MVFR VISIBILITIES AND IFR CEILINGS BETWEEN 11Z AND 15Z
WEDNESDAY.
VFR CONDITIONS EXPECTED TO PREVAIL THEREAFTER AS SURFACE WINDS VEER
TO EAST AND SOUTHEAST DURING THE DAY BELOW A GENERALLY CLEAR SKY.
COCKRELL
PREV DISCUSSION... /ISSUED 242 PM CDT TUE SEP 8 2015/
DISCUSSION...
LATEST SURFACE OBS SHOWS THE COLD FRONT EXTENDING FROM JUST NORTH OF
WHEELER SOUTHWESTWARD TO NEAR CLAUDE. MORNING SOUNDING INDICATES
CONSIDERABLE MOISTENING IN THE MID LEVELS AS EVIDENT BY WIDESPREAD
ALTOSTRATUS OBSERVED ACROSS MOST OF THE AREA. POST FRONTAL AIR MASS
IS RELATIVELY COOL ESPECIALLY WHERE MID CLOUDS ARE MOST EXTENSIVE.
TEMPERATURES AT 19Z RANGE FROM THE MID 70S TO THE MID 80S BEHIND THE
FRONT. DESPITE MOIST ADVECTION BEHIND THE FRONT IN THE
NORTHEAST...DIABATIC HEATING HAS BEEN INSUFFICIENT FOR MEANINGFUL
INSTABILITY TO DEVELOP. TEMPERATURES WERE NEAR 100 DEGREES IN THE
FAR SOUTHEAST WHERE SOUTHWESTERLY SURFACE WINDS PREVAIL AND CLOUD
COVER HAS BEEN LIMITED. THIS IS WHERE INSTABILITY HAS INCREASED THE
MOST AND GIVEN LOW/MID 60 DEGREE DEW POINTS MODERATE INSTABILITY HAS
DEVELOPED DESPITE WEAK MID LEVEL LAPSE RATES. SO FAR CONVECTION HAS
BEEN RELATIVELY BENIGN AND CONFINED MOSTLY TO ALONG AND JUST BEHIND
THE FRONT ACROSS EAST CENTRAL AND NORTHEAST PORTIONS OF THE TEXAS
PANHANDLE. SOME INTENSIFICATION SHOULD OCCUR LATER THIS AFTERNOON BUT
CHANCES WILL DECREASE FAIRLY QUICKLY LATER THIS AFTERNOON AND
ESPECIALLY BY EVENING AS LIFT ASSOCIATED WITH A WEAK SHORTWAVE SHIFTS
EASTWARD INTO OKLAHOMA. THIS SHORTWAVE IS DIFFICULT TO SEE BUT SOME
INDICATION IN WATER VAPOR IMAGERY AND RAP PV ANALYSIS SUPPORTS TRENDS
SEEN ON RADAR.
MODERATE INSTABILITY IN THE SOUTHEAST AND EAST CENTRAL TEXAS
PANHANDLE RAISES SOME CONCERN FOR SEVERE POTENTIAL. A MISALIGNMENT
OF BEST SHEAR BEHIND THE FRONT (WHERE NORTHERLY/NORTHEASTERLY FLOW
EXISTS) FROM THE MOST SIGNIFICANT INSTABILITY SOUTHEAST OF THE FRONT
IS A NEGATIVE FACTOR. WEAKLY ORGANIZED UPDRAFTS IN THE SOUTHEAST PART
OF THE TEXAS PANHANDLE THROUGH THE AFTERNOON INTO THE EARLY EVENING
COULD RESULT IN BRIEF/ISOLATED MARGINALLY SEVERE HAIL OR WIND GUSTS.
LOCALLY HEAVY RAIN WILL BE POSSIBLE GIVEN MODEST STORM MOTIONS AND A
MOIST ENVIRONMENT WITH PWATS AROUND AN INCH AND A HALF.
HAVE SCALED BACK PRECIPITATION PROBABILITIES LATER TONIGHT BASED ON
TRENDS AND AM QUITE CONFIDENT IN A DRY FORECAST FOR TOMORROW. POST
FRONTAL ENVIRONMENT WILL BE COOLER BUT ONLY SLIGHTLY BELOW NORMAL
VALUES FOR EARLY TO MID SEPTEMBER. DURING THE MID WEEK PERIOD BROAD
CYCLONIC FAIRLY SWIFT MID/UPPER FLOW WILL COVER MUCH OF THE NORTHERN
PORTIONS OF THE COUNTRY. OVERALL NOT MUCH CHANGE WAS MADE TO THE
PREVIOUS FORECAST. THE CHALLENGE WILL SHIFT TOWARD RESOLVING FAST
MOVING SHORTWAVE TROUGHS EMBEDDED WITHIN THE LARGER UPPER LOW OVER
EASTERN CANADA THROUGH THE END OF THE WEEK. MODELS BRING THE FIRST
WAVE THROUGH THE CENTRAL PLAINS LATE THURSDAY THROUGH EARLY FRIDAY
FORCING ANOTHER COLD FRONT THROUGH. CONTINUED THE TREND OF
DOWNPLAYING DAYTIME PRECIPITATION CHANCES ACROSS MUCH OF THE REGION
EXPECT THE NORTHERN TEXAS PANHANDLE AND OKLAHOMA PANHANDLE. CHANCES
SPREAD SOUTH THROUGH THE NIGHT. GIVEN BETTER MODEL AGREEMENT WE NOW
HAVE HIGHER CONFIDENCE ON COOLER WEATHER ON FRIDAY BEHIND THE FRONT
WHICH SHOULD PERSIST INTO SATURDAY. TEMPERATURES RETURN TO NEAR
NORMAL LEVELS SUNDAY INTO THE BEGINNING OF NEXT WEEK AS UPPER FLOW
PATTERN AMPLIFIES FURTHER. THE VERY PRONOUNCED WAVE IN THE GFS MODEL
EMBEDDED WITHIN THE NORTH-NORTHWESTERLY FLOW BETWEEN BUILDING RIDGE
IN THE WEST AND DEEPENING TROUGH IN THE EAST THIS WEEKEND IS FURTHER
EAST AND NOT QUITE AS PRONOUNCED. THIS IS MORE IN LINE WITH OTHER
MEDIUM RANGE GUIDANCE AND WAS ENOUGH FOR US TO KEEP THE LATTER
PORTION OF THE EXTENDED DRY FOR NOW.
BRB
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
03/10
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
640 PM CDT TUE SEP 8 2015
.AVIATION...
COLD FRONT HAS CLEARED ALL OF FORECAST AREA...WITH NO THUNDERSTORMS
EXPECTED AT TERMINALS THIS EVENING OR OVERNIGHT. WILL CONTINUE TO
MONITOR CONVECTION IN NORTHEASTERN NEW MEXICO IN CASE THOSE SHOWERS
AND THUNDERSTORMS POSE A THREAT TO KDHT.
LIGHT NORTHEAST SURFACE WINDS EXPECTED TO PREVAIL TONIGHT...WITH
POTENTIAL FOR FOG AND STRATUS TO DEVELOP WEDNESDAY MORNING. FOR
NOW...WILL FORECAST PREVAILING VFR VISIBILITIES AND SKY...WITH
OCCASIONAL MVFR VISIBILITIES AND IFR CEILINGS BETWEEN 11Z AND 15Z
WEDNESDAY.
VFR CONDITIONS EXPECTED TO PREVAIL THEREAFTER AS SURFACE WINDS VEER
TO EAST AND SOUTHEAST DURING THE DAY BELOW A GENERALLY CLEAR SKY.
COCKRELL
&&
.PREV DISCUSSION... /ISSUED 242 PM CDT TUE SEP 8 2015/
DISCUSSION...
LATEST SURFACE OBS SHOWS THE COLD FRONT EXTENDING FROM JUST NORTH OF
WHEELER SOUTHWESTWARD TO NEAR CLAUDE. MORNING SOUNDING INDICATES
CONSIDERABLE MOISTENING IN THE MID LEVELS AS EVIDENT BY WIDESPREAD
ALTOSTRATUS OBSERVED ACROSS MOST OF THE AREA. POST FRONTAL AIR MASS
IS RELATIVELY COOL ESPECIALLY WHERE MID CLOUDS ARE MOST EXTENSIVE.
TEMPERATURES AT 19Z RANGE FROM THE MID 70S TO THE MID 80S BEHIND THE
FRONT. DESPITE MOIST ADVECTION BEHIND THE FRONT IN THE
NORTHEAST...DIABATIC HEATING HAS BEEN INSUFFICIENT FOR MEANINGFUL
INSTABILITY TO DEVELOP. TEMPERATURES WERE NEAR 100 DEGREES IN THE
FAR SOUTHEAST WHERE SOUTHWESTERLY SURFACE WINDS PREVAIL AND CLOUD
COVER HAS BEEN LIMITED. THIS IS WHERE INSTABILITY HAS INCREASED THE
MOST AND GIVEN LOW/MID 60 DEGREE DEW POINTS MODERATE INSTABILITY HAS
DEVELOPED DESPITE WEAK MID LEVEL LAPSE RATES. SO FAR CONVECTION HAS
BEEN RELATIVELY BENIGN AND CONFINED MOSTLY TO ALONG AND JUST BEHIND
THE FRONT ACROSS EAST CENTRAL AND NORTHEAST PORTIONS OF THE TEXAS
PANHANDLE. SOME INTENSIFICATION SHOULD OCCUR LATER THIS AFTERNOON BUT
CHANCES WILL DECREASE FAIRLY QUICKLY LATER THIS AFTERNOON AND
ESPECIALLY BY EVENING AS LIFT ASSOCIATED WITH A WEAK SHORTWAVE SHIFTS
EASTWARD INTO OKLAHOMA. THIS SHORTWAVE IS DIFFICULT TO SEE BUT SOME
INDICATION IN WATER VAPOR IMAGERY AND RAP PV ANALYSIS SUPPORTS TRENDS
SEEN ON RADAR.
MODERATE INSTABILITY IN THE SOUTHEAST AND EAST CENTRAL TEXAS
PANHANDLE RAISES SOME CONCERN FOR SEVERE POTENTIAL. A MISALIGNMENT
OF BEST SHEAR BEHIND THE FRONT (WHERE NORTHERLY/NORTHEASTERLY FLOW
EXISTS) FROM THE MOST SIGNIFICANT INSTABILITY SOUTHEAST OF THE FRONT
IS A NEGATIVE FACTOR. WEAKLY ORGANIZED UPDRAFTS IN THE SOUTHEAST PART
OF THE TEXAS PANHANDLE THROUGH THE AFTERNOON INTO THE EARLY EVENING
COULD RESULT IN BRIEF/ISOLATED MARGINALLY SEVERE HAIL OR WIND GUSTS.
LOCALLY HEAVY RAIN WILL BE POSSIBLE GIVEN MODEST STORM MOTIONS AND A
MOIST ENVIRONMENT WITH PWATS AROUND AN INCH AND A HALF.
HAVE SCALED BACK PRECIPITATION PROBABILITIES LATER TONIGHT BASED ON
TRENDS AND AM QUITE CONFIDENT IN A DRY FORECAST FOR TOMORROW. POST
FRONTAL ENVIRONMENT WILL BE COOLER BUT ONLY SLIGHTLY BELOW NORMAL
VALUES FOR EARLY TO MID SEPTEMBER. DURING THE MID WEEK PERIOD BROAD
CYCLONIC FAIRLY SWIFT MID/UPPER FLOW WILL COVER MUCH OF THE NORTHERN
PORTIONS OF THE COUNTRY. OVERALL NOT MUCH CHANGE WAS MADE TO THE
PREVIOUS FORECAST. THE CHALLENGE WILL SHIFT TOWARD RESOLVING FAST
MOVING SHORTWAVE TROUGHS EMBEDDED WITHIN THE LARGER UPPER LOW OVER
EASTERN CANADA THROUGH THE END OF THE WEEK. MODELS BRING THE FIRST
WAVE THROUGH THE CENTRAL PLAINS LATE THURSDAY THROUGH EARLY FRIDAY
FORCING ANOTHER COLD FRONT THROUGH. CONTINUED THE TREND OF
DOWNPLAYING DAYTIME PRECIPITATION CHANCES ACROSS MUCH OF THE REGION
EXPECT THE NORTHERN TEXAS PANHANDLE AND OKLAHOMA PANHANDLE. CHANCES
SPREAD SOUTH THROUGH THE NIGHT. GIVEN BETTER MODEL AGREEMENT WE NOW
HAVE HIGHER CONFIDENCE ON COOLER WEATHER ON FRIDAY BEHIND THE FRONT
WHICH SHOULD PERSIST INTO SATURDAY. TEMPERATURES RETURN TO NEAR
NORMAL LEVELS SUNDAY INTO THE BEGINNING OF NEXT WEEK AS UPPER FLOW
PATTERN AMPLIFIES FURTHER. THE VERY PRONOUNCED WAVE IN THE GFS MODEL
EMBEDDED WITHIN THE NORTH-NORTHWESTERLY FLOW BETWEEN BUILDING RIDGE
IN THE WEST AND DEEPENING TROUGH IN THE EAST THIS WEEKEND IS FURTHER
EAST AND NOT QUITE AS PRONOUNCED. THIS IS MORE IN LINE WITH OTHER
MEDIUM RANGE GUIDANCE AND WAS ENOUGH FOR US TO KEEP THE LATTER
PORTION OF THE EXTENDED DRY FOR NOW.
BRB
&&
.PRELIMINARY POINT TEMPS/POPS...
AMARILLO TX 62 82 60 87 61 / 10 5 5 20 20
BEAVER OK 63 83 61 91 62 / 5 5 0 20 40
BOISE CITY OK 58 82 59 89 60 / 20 5 5 30 30
BORGER TX 63 85 63 90 64 / 10 5 5 20 40
BOYS RANCH TX 62 84 60 89 60 / 10 5 5 20 20
CANYON TX 63 82 59 88 61 / 20 5 5 20 20
CLARENDON TX 63 82 62 88 64 / 20 10 5 10 20
DALHART TX 58 83 59 89 59 / 20 5 5 30 30
GUYMON OK 63 84 61 90 61 / 5 5 0 30 40
HEREFORD TX 63 81 60 87 60 / 20 5 5 20 20
LIPSCOMB TX 63 83 61 89 61 / 10 0 0 20 40
PAMPA TX 62 82 61 87 60 / 20 5 0 10 40
SHAMROCK TX 65 84 62 89 63 / 20 5 0 5 30
WELLINGTON TX 66 85 62 90 65 / 30 5 0 5 20
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
03/10
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
636 PM CDT TUE SEP 8 2015
.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
&&
.AVIATION...SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE
MOSTLY CLEAR SKIES ACROSS THE CWA EARLY THIS EVENING. EXPECT VFR
CONDITIONS TO PREVAIL THE REST OF THE EVENING INTO EARLY WED
MORNING AS NORTHERLY WINDS ALOFT CONTINUE TO PROVIDE SUBSIDENCE
ACROSS THE RIO GRANDE VALLEY. A 500MB LOW ACROSS THE NORTH CENTRAL
GULF OF MEXICO WILL MOVE ACROSS THE WESTERN GULF OF MEXICO
WEDNESDAY. THIS WILL ALLOW LOW TO MID LEVEL MOISTURE TO INCREASE
ACROSS THE COASTAL SECTIONS OF THE CWA. ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS THE EASTERN PORTIONS
OF THE CWA ALONG AND AHEAD OF THE SEABREEZE FRONT MOVING INLAND
WED AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 300 PM CDT TUE SEP 8 2015/
SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... AN ACTIVE SEA
BREEZE IS MOVING SLOWLY INLAND THIS AFTERNOON. THE HRRR SUGGESTS
THAT IT WILL PUSH INTO THE MID VALLEY. DRIER AIR IS STILL IN PLACE
FARTHER WEST. SKIES SHOULD BECOME MOSTLY CLEAR TONIGHT. WV IMAGERY
SHOWS A MID LEVEL CIRCULATION SOUTH OF LOUISIANA...WHICH IS
PROGGED TO DRIFT SOUTHWEST TOWARD THE AREA. THUS...LOOK FOR
CONTINUED UNSETTLED CONDITIONS OVER THE GULF...WITH A FEW SHOWERS
TRANSLATING FARTHER WEST OVER THE COAST TONIGHT. THE NAM SHOWS
DRIER AIR AGAIN OUT WEST ON WEDNESDAY...SO WILL ANTICIPATE SIMILAR
CONDITIONS AS TODAY WITH MAYBE A LITTLE MORE ACTIVITY OVER THE
COASTAL AREAS. THE MOISTURE POOLING ALONG AND AHEAD OF A FRONT
MOVING SOUTH OVER CENTRAL TEXAS WILL NOT BE FAR ENOUGH SOUTH TO
CAUSE A MAJOR PROBLEM IN THE SHORT TERM...EXCEPT PERHAPS FOR A FEW
SHOWERS OVER THE FAR NORTHWEST... ZAPATA COUNTY...WEDNESDAY NIGHT.
LONG TERM /THURSDAY THROUGH TUESDAY/...
H5 TROUGH REMAINS BOTTLED BETWEEN 2 RIDGES...WITH THE AXIS
REMAINING TO THE EAST ON THURSDAY. THIS WILL KEEP THE REGION ON
THE DRIER WEST SIDE THURSDAY AND INTO FRIDAY. FRIDAY BRINGS THE
TROUGH AXIS WESTWARD AS THE OVERALL TROUGH DEEPENS. AN INCREASE IN
MOISTURE FROM THE SOUTH WILL BEGIN TO RAMP UP POPS LATER FRIDAY
AFTERNOON. GOOD DEEP MOISTURE AND INSTABILITY COMBINES ON
SATURDAY FOR A GOOD CHANCES FOR SHOWERS AND THUNDERSTORMS. SUNDAY
INTO MONDAY A WEAK COLD FRONT TRIES TO MOVE SOUTHWARD INTO SOUTH
TEXAS. THE MAIN ISSUE IS SOUTHWARD MOVING DRIER AIR AND HOW FAR
SOUTH IT WILL REACH...CLASHING WITH GULF MOISTURE MOVING BACK TO
THE NORTH. CONTINUING WITH A GOOD CHANCE FOR THUNDERSTORMS BOTH
DAYS AS INSTABILITY REMAINS DECENT. QUESTION MARKS CROP UP
STARTING EARLY NEXT WEEK AS MODELS DIFFER ON WHAT HAPPENS TO THE
REMNANTS OF THE FRONT. NEEDLESS TO SAY...A DEGRADING FRONT
HOVERING IN THE WESTERN GULF NEEDS TO HAVE A CLOSE EYE KEPT ON IT.
FOR NOW...THE LOCALIZED INSTABILITY RAIN CHANCES CONTINUE TUESDAY
INTO WEDNESDAY...ESPECIALLY CLOSER TO THE COAST...AS WE MOVE INTO
OUR CLIMATOLOGICALLY WETTEST WEEK OF THE ENTIRE YEAR.
MARINE...
A WEAK PRESSURE GRADIENT WILL CAUSE LIGHT TO MODERATE SOUTHEAST
TO SOUTH WINDS AND LOW TO MODERATE SEAS TO PERSIST ALONG THE LOWER
TEXAS COAST.
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
61/55/BIRCHFIELD
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1200 PM CDT MON SEP 7 2015
.AVIATION...
/12Z TAFS/
Expect VFR conditions at the terminals the next 24 hours. The
winds will be south at 5 to 10 knots.
&&
.PREV DISCUSSION... /ISSUED 628 AM CDT MON SEP 7 2015/
AVIATION...
/12Z TAFS/
MVFR stratus in the Hill Country was advecting north to the I-10
corridor from Sonora to Junction at 11Z. Will include a tempo for
MVFR ceiling at KSOA and KJCT through 16Z. Otherwise, south to
southeast winds of 10 KTS or less, and VFR conditions are expected
across the rest of the terminals.
PREV DISCUSSION... /ISSUED 356 AM CDT MON SEP 7 2015/
SHORT TERM...
(Today and Tonight)
It will be another persistence forecast today, with the upper
ridge parked over West Central Texas. The HRRR model again
develops isolated afternoon convection, as it has done the last
several days, and will discount the potential. Temperatures should
again rise into the upper 90s with a few areas reaching 100.
04
LONG TERM...
(Tuesday through Sunday)
We looking for one more hot and dry day across west central TX
before the synoptic pattern shifts to one more conducive for
increasing rain chances and more seasonal temperatures. The
subtropical ridge will be building slowly westward on Tuesday as a
strong trough moves across the northern Plains. This trough is
progged to dig over the eastern CONUS, allowing the ridge to build
over the western states. This will result in northwest flow aloft
for our neck of the woods. A weak cold front will move south into
the Lone Star State Tuesday afternoon, likely reaching the south
Plains during the evening hours. Compressional heating ahead of
this cold front will promote afternoon highs in the mid 90s to
near 100 degrees.
Convection is expected to initiate along this cold front as it
approaches Tuesday evening. Some of this activity is expected to
move southeast into the Big Country, maybe as far south as the
Colorado River, Tuesday night into early Wednesday morning. The
cold front is expected to weaken by this time, but convective
outflow should serve as the effective frontal boundary, moving
south into the Concho Valley, and eventually the I-10 corridor,
by Wednesday afternoon. Scattered showers and thunderstorms are
expected to develop, especially along and behind the front. While
rainfall is not expected to be particularly heavy, it should be
fairly widespread with good coverage across the CWA. The increased
cloud cover and precipitation will keep temperatures in check.
Forecast highs for Wednesday afternoon are in the upper 80s to
lower 90s; however, they could be lowered further if rain is
indeed as widespread as anticipated.
The effective cold front will move south over the Edwards Plateau
Wednesday night into Thursday. This will shift the highest rain
chances south of a San Angelo-Brownwood line, favoring the I-10
corridor. In fact, PoPs were removed for areas north of I-20 on
Thursday. This boundary will become more diffuse by the end of the
work-week, but slight chance PoPs were retained over the southern
1/3 of the CWA for Friday. Total rainfall amounts will likely
average less than 1/2 inch, some some areas will see locally
higher amounts, especially over the southeast quadrant of the CWA.
Temperatures are forecast to remain near seasonal norms Thursday
and Friday, generally in the upper 80s to lower 90s. Overnight
lows during this time will be in the mid 60s to near 70 degrees.
PoPs were removed over the weekend as the main upper-level trough
is expected to be to our east by Saturday. Temperatures are
expected to remain near climatology. There remain some differences
in the synoptic pattern, the most notable of which is the tropical
system generated early next week in the western Gulf by the ECMWF.
At the same time, the GFS creates no such system and maintains a
weak cut-off upper-low over the Red River. Will continue to
monitor the model trends at this time, keeping a dry forecast over
the weekend.
Johnson
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 99 76 98 73 / 0 0 5 30
San Angelo 100 75 100 74 / 0 0 0 10
Junction 98 74 97 75 / 0 0 5 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
21
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
628 AM CDT MON SEP 7 2015
.AVIATION...
/12Z TAFS/
MVFR stratus in the Hill Country was advecting north to the I-10
corridor from Sonora to Junction at 11Z. Will include a tempo for
MVFR ceiling at KSOA and KJCT through 16Z. Otherwise, south to
southeast winds of 10 KTS or less, and VFR conditions are expected
across the rest of the terminals.
&&
.PREV DISCUSSION... /ISSUED 356 AM CDT MON SEP 7 2015/
SHORT TERM...
(Today and Tonight)
It will be another persistence forecast today, with the upper
ridge parked over West Central Texas. The HRRR model again
develops isolated afternoon convection, as it has done the last
several days, and will discount the potential. Temperatures should
again rise into the upper 90s with a few areas reaching 100.
04
LONG TERM...
(Tuesday through Sunday)
We looking for one more hot and dry day across west central TX
before the synoptic pattern shifts to one more conducive for
increasing rain chances and more seasonal temperatures. The
subtropical ridge will be building slowly westward on Tuesday as a
strong trough moves across the northern Plains. This trough is
progged to dig over the eastern CONUS, allowing the ridge to build
over the western states. This will result in northwest flow aloft
for our neck of the woods. A weak cold front will move south into
the Lone Star State Tuesday afternoon, likely reaching the south
Plains during the evening hours. Compressional heating ahead of
this cold front will promote afternoon highs in the mid 90s to
near 100 degrees.
Convection is expected to initiate along this cold front as it
approaches Tuesday evening. Some of this activity is expected to
move southeast into the Big Country, maybe as far south as the
Colorado River, Tuesday night into early Wednesday morning. The
cold front is expected to weaken by this time, but convective
outflow should serve as the effective frontal boundary, moving
south into the Concho Valley, and eventually the I-10 corridor,
by Wednesday afternoon. Scattered showers and thunderstorms are
expected to develop, especially along and behind the front. While
rainfall is not expected to be particularly heavy, it should be
fairly widespread with good coverage across the CWA. The increased
cloud cover and precipitation will keep temperatures in check.
Forecast highs for Wednesday afternoon are in the upper 80s to
lower 90s; however, they could be lowered further if rain is
indeed as widespread as anticipated.
The effective cold front will move south over the Edwards Plateau
Wednesday night into Thursday. This will shift the highest rain
chances south of a San Angelo-Brownwood line, favoring the I-10
corridor. In fact, PoPs were removed for areas north of I-20 on
Thursday. This boundary will become more diffuse by the end of the
work-week, but slight chance PoPs were retained over the southern
1/3 of the CWA for Friday. Total rainfall amounts will likely
average less than 1/2 inch, some some areas will see locally
higher amounts, especially over the southeast quadrant of the CWA.
Temperatures are forecast to remain near seasonal norms Thursday
and Friday, generally in the upper 80s to lower 90s. Overnight
lows during this time will be in the mid 60s to near 70 degrees.
PoPs were removed over the weekend as the main upper-level trough
is expected to be to our east by Saturday. Temperatures are
expected to remain near climatology. There remain some differences
in the synoptic pattern, the most notable of which is the tropical
system generated early next week in the western Gulf by the ECMWF.
At the same time, the GFS creates no such system and maintains a
weak cut-off upper-low over the Red River. Will continue to
monitor the model trends at this time, keeping a dry forecast over
the weekend.
Johnson
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 99 76 98 73 / 0 0 5 30
San Angelo 100 75 100 74 / 0 0 0 10
Junction 98 74 97 75 / 0 0 5 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
99/99/04
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
356 AM CDT MON SEP 7 2015
.SHORT TERM...
(Today and Tonight)
It will be another persistence forecast today, with the upper
ridge parked over West Central Texas. The HRRR model again
develops isolated afternoon convection, as it has done the last
several days, and will discount the potential. Temperatures should
again rise into the upper 90s with a few areas reaching 100.
04
.LONG TERM...
(Tuesday through Sunday)
We looking for one more hot and dry day across west central TX
before the synoptic pattern shifts to one more conducive for
increasing rain chances and more seasonal temperatures. The
subtropical ridge will be building slowly westward on Tuesday as a
strong trough moves across the northern Plains. This trough is
progged to dig over the eastern CONUS, allowing the ridge to build
over the western states. This will result in northwest flow aloft
for our neck of the woods. A weak cold front will move south into
the Lone Star State Tuesday afternoon, likely reaching the south
Plains during the evening hours. Compressional heating ahead of
this cold front will promote afternoon highs in the mid 90s to
near 100 degrees.
Convection is expected to initiate along this cold front as it
approaches Tuesday evening. Some of this activity is expected to
move southeast into the Big Country, maybe as far south as the
Colorado River, Tuesday night into early Wednesday morning. The
cold front is expected to weaken by this time, but convective
outflow should serve as the effective frontal boundary, moving
south into the Concho Valley, and eventually the I-10 corridor,
by Wednesday afternoon. Scattered showers and thunderstorms are
expected to develop, especially along and behind the front. While
rainfall is not expected to be particularly heavy, it should be
fairly widespread with good coverage across the CWA. The increased
cloud cover and precipitation will keep temperatures in check.
Forecast highs for Wednesday afternoon are in the upper 80s to
lower 90s; however, they could be lowered further if rain is
indeed as widespread as anticipated.
The effective cold front will move south over the Edwards Plateau
Wednesday night into Thursday. This will shift the highest rain
chances south of a San Angelo-Brownwood line, favoring the I-10
corridor. In fact, PoPs were removed for areas north of I-20 on
Thursday. This boundary will become more diffuse by the end of the
work-week, but slight chance PoPs were retained over the southern
1/3 of the CWA for Friday. Total rainfall amounts will likely
average less than 1/2 inch, some some areas will see locally
higher amounts, especially over the southeast quadrant of the CWA.
Temperatures are forecast to remain near seasonal norms Thursday
and Friday, generally in the upper 80s to lower 90s. Overnight
lows during this time will be in the mid 60s to near 70 degrees.
PoPs were removed over the weekend as the main upper-level trough
is expected to be to our east by Saturday. Temperatures are
expected to remain near climatology. There remain some differences
in the synoptic pattern, the most notable of which is the tropical
system generated early next week in the western Gulf by the ECMWF.
At the same time, the GFS creates no such system and maintains a
weak cut-off upper-low over the Red River. Will continue to
monitor the model trends at this time, keeping a dry forecast over
the weekend.
Johnson
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 99 76 98 73 / 0 0 5 30
San Angelo 100 75 100 74 / 0 0 0 10
Junction 98 74 97 75 / 0 0 5 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
04/25
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 249 PM CDT MON SEP 7 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A WEAK COLD
FRONT DROPPING SOUTHEAST FROM THE BAY OF GREEN BAY TO WAUTOMA EARLY
THIS AFTERNOON. AHEAD OF THE FRONT...CLOUDS ARE FAIRLY WIDESPREAD WITH
SCT SHOWERS DEVELOPING OVER THE PAST HOUR OVER THE NORTHERN FOX VALLEY.
LOOK FOR THESE SHOWERS TO CONTINUE TO DEVELOP AHEAD OF THE FRONT OVER
THE NEXT FEW HOURS. BEHIND THE FRONT...MORE BREAKS IN THE CLOUDS EXIST...BUT
THE AIRMASS REMAINS RELATIVELY HUMID UNTIL BEHIND A SECONDARY
FRONT OVER FAR NORTHWEST WISCONSIN AND CENTRAL MINNESOTA. AS A
SHORTWAVE OVER COLORADO MOVES NORTHEAST TONIGHT...SHOWER AND THUNDERSTORMS
CHANCES AS WELL AS POTENTIAL FOR HEAVY RAINFALL ARE THE MAIN FORECAST
CONCERNS.
TONIGHT...THE SURFACE COLD FRONT WILL SAG INTO SOUTHERN WISCONSIN
THIS EVENING. WEAK SHORTWAVE ENERGY EMANATING OUT OF COLORADO WILL
LIFT NORTHEAST TONIGHT AND MOVE INTO THE WESTERN GREAT LAKES AFTER
MIDNIGHT. MID-LEVEL FLOW WILL BACK AHEAD OF THE SHORTWAVE CAUSING
AIR TO RISE OVER THE STALLED BOUNDARY. MODELS HAVE BACKED OFF RAIN
CHANCES WITH THEIR 12Z RUNS HOWEVER...SO WILL FOLLOW SUIT BY KEEPING
ONLY VERY LOW CHANCES OVER THE FAR SOUTHERN CWA THROUGH THE EVENING
AND ONLY RAMP UP PRECIP CHANCES INTO THE LOW LIKELY RANGE OVER EAST-
CENTRAL WI AFTER 09Z. WINDS WILL SHIFT TO THE NORTHEAST BRIEFLY
THIS EVENING WHICH WILL PROMOTE SOME DRIER AIR FILTERING IN TO N-C
WISCONSIN. AS WINDS SHIFT AROUND TO THE SOUTHEAST...MORE OF THE
MOIST/TROPICAL AIR WILL GET RECYCLED WESTWARD...WHICH MAY CREATE FOG
ISSUES IN THIS AREA. HOWEVER...MID AND HIGH CLOUDS WILL BE ARRIVING
BY 06Z...SO WHILE LOWER VSBYS ARE LIKELY...THE PROBABILITY FOR
WIDESPREAD DENSE FOG SEEMS PRETTY LOW. WILL KEEP A PATCHY MENTION
IN THE FORECAST. LOWS RANGING FROM THE MID 50S NORTH TO MID 60S
SOUTH.
TUESDAY...THE SHORTWAVE WILL CONTINUE TO QUICKLY ADVANCE NE INTO
LOWER MICHIGAN BY 18Z BUT A WEAK SURFACE LOW TRAVELLING ALONG THE
STALLED BOUNDARY MAY NOT REACH CENTRAL LAKE MICHIGAN UNTIL 18Z.
WEAK MID-LEVEL FGEN NORTH OF THE LOW IN CONCERT WITH UPPER
DIVERGENCE SHOULD CREATE AN AREA OF RAIN WITH EMBEDDED TSTORMS OVER
CENTRAL AND NORTHEAST WI DURING THE MORNING...WHICH WILL EXIT IN THE
AFTERNOON. PWATS WILL REMAIN NEAR 2.0...SO LOCALLY AMOUNTS OF RAIN
UP TO AN INCH LOOK POSSIBLE...MAINLY OVER EAST-CENTRAL WI. BUT IT
LOOKS LIKE THIS POSSIBILITY WILL BE TO THE EAST OF THE DRENCH AREAS
OF CENTRAL WI. SO DO NOT SEE A NEED FOR A FLASH FLOOD WATCH AT THIS
TIME. CLOUDY WITH HIGHS IN THE LOW TO MID 70S.
.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 249 PM CDT MON SEP 7 2015
DRIER AND COOLER AIR WILL RETURN TO THE REGION WEDNESDAY AND
WEDNESDAY NIGHT AS WEAK SURFACE RIDGING ARRIVES FROM THE PLAINS
STATES. A SHARP UPPER TROUGH DIVING SOUTHEAST FROM CANADA SHOULD
INDUCE A WAVE ALONG A COLD FRONT THAT WILL MOVE ACROSS THE AREA
THURSDAY AND THURSDAY NIGHT. CYCLONIC UPPER FLOW MAY KEEP THE
SHOWERS GOING FRIDAY. DRY...SEASONABLE WEATHER IS EXPECTED
SATURDAY AND SUNDAY AS THE UPPER TROUGH EXITS AND SURFACE HIGH
BUILDS IN.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1204 PM CDT MON SEP 7 2015
A COLD FRONT WILL BE MOVING ACROSS THE AREA THIS
AFTERNOON. ANY SHOWERS OR STORMS ARE EXPECTED TO BE TOO ISOLATED TO
INCLUDE IN THE TAFS. CLEARING SKIES SHOULD MOVE IN FROM NORTHWEST
TO SOUTHEAST THROUGH THE AFTERNOON...THOUGH CLOUDS MAY NEVER DEPART
AT MTW. AHEAD OF A LOW PRESSURE SYSTEM...CIGS/VSBYS ARE EXPECTED TO
FALL AGAIN TONIGHT WITH A CHANCE OF RAIN MOVING IN LATE. BEST
CHANCES OF RAIN WILL OCCUR OVER CENTRAL AND EAST-CENTRAL WI.
WIDESPREAD IFR CONDITIONS ARE LIKELY...POSSIBLY LOWER WITHIN THE
RAIN. SOME MARGINAL IMPROVEMENT IS POSSIBLE BY THE END OF THE TAF
PERIOD.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......RDM
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1158 PM CDT SUN SEP 6 2015
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 249 PM CDT SUN SEP 6 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A COLD
FRONT RUNNING SOUTHWEST FROM NORTHERN MINNESOTA TO EASTERN SOUTH
DAKOTA EARLY THIS AFTERNOON. DESPITE ML CAPES UPWARDS OF 2000 J/KG
OVER CENTRAL MINNESOTA...THE FRONT IS MOSTLY INACTIVE AS A RESULT OF
CIN GREATER THAN 100 J/KG. STILL RATHER UNCERTAIN HOW CONVECTION
WILL EVOLVE LATER THIS AFTERNOON. MOST MESOMODELS SHOW CONVECTION
DEVELOPING AFTER 21Z...BUT THIS WILL BE AROUND THE SAME TIME AS THE
RIGHT FRONT QUAD OF A JET STREAK MOVES OVERHEAD. AS A
RESULT...THINK CONVECTION WILL NOT BE AS ROBUST AS THE ARW/NMM...AND
MORE ISOLATED TO SCATTERED LIKE THE HRRR. OTHERWISE...THE MID-LEVEL
THETAE AND PWAT PLUME WILL CONTINUE TO PUSH IN SCATTERED LIGHT
SHOWERS AND ISOLATED TSTORMS FOR THE REST OF THE AFTERNOON INTO
CENTRAL AND N-C WISCONSIN. TEMPS MAY NOT GET TO THEIR EARLIER
FORECAST HIGHS IN THESE AREAS AS A RESULT. AS THE COLD FRONT MOVES
EAST TONIGHT...THUNDERSTORMS CHANCES AND IMPACTS ARE THE MAIN
FORECAST CONCERNS.
TONIGHT...THE COLD FRONT WILL MOVE EAST TONIGHT...REACHING N-C
WISCONSIN BY 06Z AND NORTHEAST WISCONSIN BY 12Z. AT LEAST SCT
CONVECTION STILL LOOKS TO FIRE OVER MINNESOTA...BUT THINK IT WILL
REMAIN RATHER UNORGANIZED TO THE LARGE CIN AND UPPER LEVEL
SUBSIDENCE. BUT AS THE FRONT DRAWS CLOSER TO THE PWAT PLUME OVER
WESTERN WISCONSIN...THE ECMWF/GFS/GEM ALL DEVELOP WIDESREAD SHOWERS
AND STORMS AFTER 00Z. ALONG WITH PWATS GREATER THAN 2.0
INCHES...ELEVATED INSTABILITY WILL REACH 1000-2000 J/KG WITH LITTLE
TO NO CIN. SO WENT WITH THIS IDEA IN THE FORECAST...INCREASING
PRECIP CHANCES QUICKLY IN THE 00-03Z TIME PERIOD. PRECIP IS
EXPECTED TO WEAKEN SOME BY THE TIME IT REACHES THE LAKE MICHIGAN
SHORELINE LATE TONIGHT. SINCE EFFECTIVE BULK SHEARS WILL GENERALLY
BE UNDER 20 KTS BY THE TIME CONVECTION DEVELOPS...THINK ANY SEVERE
THREAT IS RATHER LOW. ISOLATED STRONG GUSTY WINDS STILL APPEAR
REASONABLE...ALONG WITH LOCALLY HEAVY RAINFALL.
MONDAY...THE FRONT WILL STILL BE BISECTING THE FORECAST AREA FROM NE
WI TO CENTRAL WI AT THE START OF THE MORNING. SCT SHOWERS AND
STORMS WILL BE POSSIBLE ALONG THE FRONT OVER CENTRAL AND FAR NE
WISCONSIN DURING THE MORNING...AND EAST-CENTRAL WI THROUGH LATE
AFTERNOON. CLOUD COVER SHOULD BE WIDESPREAD AHEAD OF THE
FRONT...BUT IF CLOUDS DO BREAK FOR A PERIOD...INSTABILITY OVER EAST-
CENTRAL WI COULD BECOME SUFFICIENT FOR STRONG STORMS TO DEVELOP.
SEVERE STORMS ARE UNLIKELY GIVEN THE POOR SHEAR OF 15-20KTS. BEHIND
THE FRONT...N-C WI SHOULD SEE CLEARING TAKE PLACE IN THE AFTERNOON
AFTER A CLOUDY START. COOLER HIGHS IN THE MID 70S TO LOW 80S.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 249 PM CDT SUN SEP 6 2015
THE COLD FRONT WILL MAKE IT INTO SOUTHERN WISCONSIN OR NORTHERN
ILLINOIS MONDAY NIGHT BEFORE RETURNING NORTHWARD AS A WAVE MOVES
NORTHEAST ALONG THE FRONT. THE FRONT WILL BE SHALLOW SO THERE WILL
LIKELY BE OVERRUNNING SHOWERS AND THUNDERSTORMS ACROSS THE
SOUTHEAST HALF OF THE FORECAST AREA TUESDAY. THE FRONT SHOULD MOVE
FAR ENOUGH SOUTH WEDNESDAY FOR DRIER AIR TO RETURN FOR AWHILE. IT
WILL ALSO BE COOLER AND LESS HUMID.
AN UPPER TROUGH WILL MOVE ACROSS THE REGION THURSDAY AND BRING A
CHANCE OF SHOWERS FOLLOWED BY NORTHWEST UPPER FLOW AND MUCH COOLER
AND DRIER AIR FOR THE REMAINDER OF THE WEEK. LOWS IN THE 30S ARE
POSSIBLE IN FAR NORTHERN WISCONSIN FRIDAY NIGHT.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1155 PM CDT SUN SEP 6 2015
SHOWERS AND EMBEDDED TSTMS WILL CONTINUE TO MOVE THROUGH THE
REGION OVERNIGHT...WITH POCKETS OF HEAVY RAINFALL...AND ASSOCIATED
MVFR/IFR CONDITIONS. PATCHY LOW CLOUDS (POSSIBLE IFR/LIFR) MAY
ALSO ACCOMPANY THE FRONTAL PASSAGE AND LINGER INTO MONDAY MORNING
BEFORE ERODING/LIFTING. CONDITIONS SHOULD IMPROVE TO VFR AT MOST
LOCATIONS BY EARLY MONDAY AFTERNOON.
KEPT LLWS IN THE GRB/ATW/MTW TAFS FOR THE FIRST FEW HOURS OF THE
TAF PERIOD...WITH WSW WINDS AROUND 35 KTS AROUND 1000 FT AGL.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......RDM
AVIATION.......KIECKBUSCH
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1135 AM MDT MON SEP 7 2015
.UPDATE...
ISSUED AT 950 AM MDT MON SEP 7 2015
LATEST GUIDANCE SHOWING SOME PRETTY HIGH CAPE OUT OVER THE
SOUTHERN NEBRASKA PANHANDLE ALONG AND SOUTH OF AN ALLIANCE TO
CHEYENNE LINE THIS AFTERNOON. SPC HRRR SIMULATED RADAR SHOWING
QUITE A BIT OF CONVECTION OUT IN THIS AREA THIS AFTERNOON AND
EARLY EVENING. WENT AHEAD AND UPPED POPS FOR THIS AREA THIS
AFTERNOON/EARLY EVENING. UPDATES HAVE BEEN SENT.
AS FOR THE CURRENT RFW...LOOKS TO BE IN PRETTY GOOD SHAPE. POOR
OVERNIGHT RH RECOVERIES FOR 301 AND 302...SO WE ARE STARTING OFF
PRETTY LOW ALREADY THIS MORNING. NAM SOUNDINGS SHOWING 35-40KTS OF
WIND POSSIBLY MIXING DOWN TO THE SURFACE THIS AFTERNOON. WILL KEEP
CURRENT HEADLINES AS THEY ARE.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 415 AM MDT MON SEP 7 2015
PREDAWN WATER VAPOR IMAGERY SHOWED A UPPER LOW SITUATED OVER
CENTRAL SASKATCHEWAN WITH A TROUGH AXIS THROUGH THE NORTHERN
ROCKIES AND GREAT BASIN. UPPER RIDGE EXTENDED FROM NORTHERN MX
TO THE MIDWEST. THE REGIONAL SURFACE ANALYSIS PLACED A COLD
FRONT FROM LAKE SUPERIOR THROUGH CENTRAL IA AND KS THEN NORTH
ALONG THE CO FRONT RANGE AND WEST THROUGH CENTRAL UT. A WEAK
TROUGH WAS LOCATED NEAR THE LARAMIE RANGE. WIDELY SCATTERED
CONVECTION DEVELOPED IN THE VICINITY OF THESE BOUNDARIES...
AIDED BY LIFT FROM RIGHT REAR QUADRANT OF UPPER LEVEL JET.
REGIONAL RADARS DETECTED SHOWERS AND ISOLATED TSTORMS MOVING
NORTHEAST ACROSS WESTERN NE AS WELL AS FROM NORTHWEST CO INTO
SOUTH CENTRAL WY.
THERE IS GOOD AGREEMENT WITH THE 00Z SHORT RANGE MODEL GUIDANCE
PROGGING THE UPPER TROUGH AXIS TO THE WEST TO TRANSLATE EAST
DURING THE NEXT 24 HOURS. THE RIGHT REAR QUADRANT OF THE UPPER
JET WILL REMAIN OVER THE CWA THROUGH TONIGHT. THIS FEATURE ALONG
WITH A COOL FRONT DROPPING SOUTHEAST THROUGH THE PLAINS LATE
TODAY WILL TRIGGER WIDELY SCATTERED AFTERNOON AND EVENING
CONVECTION...MAINLY FROM SOUTHERN LARAMIE RANGE NORTHEAST INTO THE
NE PANHANDLE. TEMPERATURES TODAY WILL BE SIMILAR TO YESTERDAY WITH
HIGHS IN THE 60S AND 70S WEST TO THE 80S EAST. THERE WILL BE A
30-DEGREE WEST TO EAST DEW POINT GRADIENT THIS AFTERNOON. GUSTY
WESTERLY WINDS AND LOW HUMIDITIES WILL INCREASE THE FIRE DANGER
OVER PORTIONS OF EAST AND SOUTH CENTRAL WY THIS AFTERNOON.
TUESDAY WILL BE 5 TO 10 DEGREES COOLER ACROSS THE PLAINS FOLLOWING
THE FRONTAL PASSAGE. THE DRIER AIR MASS WILL SPREAD EAST INTO THE
NE PANHANDLE DURING THE DAY. BREEZY WEST WINDS AND LOW HUMIDITIES
WILL CREATE NEAR-CRITICAL FIRE WEATHER CONDITIONS WEST OF THE
LARAMIE RANGE. THE FLOW ALOFT BECOMES MORE ZONAL WEDNESDAY. IT
WILL BE DRY AND BREEZY DURING THE AFTERNOON ALONG AND WEST OF THE
LARAMIE RANGE. TEMPERATURES WEDNESDAY WILL WARM ABOUT 5 DEGREES.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 330 AM MDT MON SEP 7 2015
WEDNESDAY NIGHT/THURSDAY...FLOW ALOFT REMAINS NORTHWEST. WITH
LIMITED LOW AND MID LEVEL MOISTURE...NOT EXPECTING ANY PRECIPITATION.
FRIDAY...NEAR THE SAME OR SLIGHTLY WARMER THAN THURSDAY BASED ON
THICKNESS AND HEIGHT CHANGES. LOW AND MID LEVEL MOISTURE LOOKS TOO
SCANT FOR ANY PRECIPITATION.
SATURDAY...SLOW WARMING TREND CONTINUES AS RIDGING ALOFT BECOMES
MORE PRONOUNCED OVERHEAD. STILL NOT ENOUGH LOW AND MID LEVEL
MOISTURE FOR SHOWER AND THUNDERSTORM FORMATION.
SUNDAY...FLOW ALOFT BECOMES ZONAL...INDUCING EVEN WARMER TEMPERATURES.
STILL DRY WITH LIMITED CLOUD COVER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH TUESDAY MORNING)
VFR CONDITIONS WILL PREVAIL ACROSS SOUTHEAST WYOMING AND MOST OF
WESTERN NEBRASKA THROUGH TONIGHT. SCATTERED SHOWERS AND ISOLATED
THUNDER WILL DEVELOP NEAR OR JUST EAST OF THE SOUTHERN LARAMIE RANGE
AND MOVE EAST THROUGH THIS EVENING. BRIEF MVFR VIS ARE POSSIBLE
AROUND KCYS AND KSNY BEFORE THE ACTIVITY DISSIPATES BY 03Z. THERE IS
A SLIGHT CHANCE OF LOW CIGS AND PATCHY FOG ACROSS THE WESTERN
NEBRASKA TERMINALS AND KCYS BY EARLY TUESDAY MORNING.
&&
.FIRE WEATHER...
ISSUED AT 310 AM MDT MON SEP 7 2015
CRITICAL FIRE WEATHER CONDITIONS WILL DEVELOP ONCE AGAIN THIS
AFTERNOON FOR PORTIONS OF EAST AND SOUTH CENTRAL WYOMING. WESTERLY
WINDS WILL FREQUENTLY GUST FROM 25 TO 35 MPH WITH MINIMUM RELATIVE
HUMIDITIES DECREASING TO 10 TO 15 PERCENT. THESE CRITICAL CONDITIONS
WILL DEVELOP ACROSS MOST OF ZONE 302...WESTERN PORTIONS OF ZONE
301...AND NORTHERN PORTIONS OF ZONES 303 AND 308. A COOL FRONT
WILL MOVE ACROSS THE PLAINS THIS EVENING...WITH SLIGHTLY COOLER
TEMPERATURES FOR TUESDAY. THERE IS A SLIGHT CHANCE OF AFTERNOON
AND EVENING SHOWERS AND THUNDERSTORMS ALONG AND EAST OF THE
SOUTHERN LARAMIE RANGE. NEAR CRITICAL FIRE WEATHER CONDITIONS ARE
EXPECTED TUESDAY AND WEDNESDAY FOR AREAS ALONG AND WEST OF THE
LARAMIE RANGE.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR WYZ301>303-308.
NE...NONE.
&&
$$
UPDATE...GCC
SHORT TERM...MAJ
LONG TERM...RUBIN
AVIATION...TJT
FIRE WEATHER...MAJ
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
955 AM MDT MON SEP 7 2015
.UPDATE...
ISSUED AT 950 AM MDT MON SEP 7 2015
LATEST GUIDANCE SHOWING SOME PRETTY HIGH CAPE OUT OVER THE
SOUTHERN NEBRASKA PANHANDLE ALONG AND SOUTH OF AN ALLIANCE TO
CHEYENNE LINE THIS AFTERNOON. SPC HRRR SIMULATED RADAR SHOWING
QUITE A BIT OF CONVECTION OUT IN THIS AREA THIS AFTERNOON AND
EARLY EVENING. WENT AHEAD AND UPPED POPS FOR THIS AREA THIS
AFTERNOON/EARLY EVENING. UPDATES HAVE BEEN SENT.
AS FOR THE CURRENT RFW...LOOKS TO BE IN PRETTY GOOD SHAPE. POOR
OVERNIGHT RH RECOVERIES FOR 301 AND 302...SO WE ARE STARTING OFF
PRETTY LOW ALREADY THIS MORNING. NAM SOUNDINGS SHOWING 35-40KTS OF
WIND POSSIBLY MIXING DOWN TO THE SURFACE THIS AFTERNOON. WILL KEEP
CURENT HEADLINES AS THEY ARE.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 415 AM MDT MON SEP 7 2015
PREDAWN WATER VAPOR IMAGERY SHOWED A UPPER LOW SITUATED OVER
CENTRAL SASKATCHEWAN WITH A TROUGH AXIS THROUGH THE NORTHERN
ROCKIES AND GREAT BASIN. UPPER RIDGE EXTENDED FROM NORTHERN MX
TO THE MIDWEST. THE REGIONAL SURFACE ANALYSIS PLACED A COLD
FRONT FROM LAKE SUPERIOR THROUGH CENTRAL IA AND KS THEN NORTH
ALONG THE CO FRONT RANGE AND WEST THROUGH CENTRAL UT. A WEAK
TROUGH WAS LOCATED NEAR THE LARAMIE RANGE. WIDELY SCATTERED
CONVECTION DEVELOPED IN THE VICINITY OF THESE BOUNDARIES...
AIDED BY LIFT FROM RIGHT REAR QUADRANT OF UPPER LEVEL JET.
REGIONAL RADARS DETECTED SHOWERS AND ISOLATED TSTORMS MOVING
NORTHEAST ACROSS WESTERN NE AS WELL AS FROM NORTHWEST CO INTO
SOUTH CENTRAL WY.
THERE IS GOOD AGREEMENT WITH THE 00Z SHORT RANGE MODEL GUIDANCE
PROGGING THE UPPER TROUGH AXIS TO THE WEST TO TRANSLATE EAST
DURING THE NEXT 24 HOURS. THE RIGHT REAR QUADRANT OF THE UPPER
JET WILL REMAIN OVER THE CWA THROUGH TONIGHT. THIS FEATURE ALONG
WITH A COOL FRONT DROPPING SOUTHEAST THROUGH THE PLAINS LATE
TODAY WILL TRIGGER WIDELY SCATTERED AFTERNOON AND EVENING
CONVECTION...MAINLY FROM SOUTHERN LARAMIE RANGE NORTHEAST INTO THE
NE PANHANDLE. TEMPERATURES TODAY WILL BE SIMILAR TO YESTERDAY WITH
HIGHS IN THE 60S AND 70S WEST TO THE 80S EAST. THERE WILL BE A
30-DEGREE WEST TO EAST DEW POINT GRADIENT THIS AFTERNOON. GUSTY
WESTERLY WINDS AND LOW HUMIDITIES WILL INCREASE THE FIRE DANGER
OVER PORTIONS OF EAST AND SOUTH CENTRAL WY THIS AFTERNOON.
TUESDAY WILL BE 5 TO 10 DEGREES COOLER ACROSS THE PLAINS FOLLOWING
THE FRONTAL PASSAGE. THE DRIER AIR MASS WILL SPREAD EAST INTO THE
NE PANHANDLE DURING THE DAY. BREEZY WEST WINDS AND LOW HUMIDITIES
WILL CREATE NEAR-CRITICAL FIRE WEATHER CONDITIONS WEST OF THE
LARAMIE RANGE. THE FLOW ALOFT BECOMES MORE ZONAL WEDNESDAY. IT
WILL BE DRY AND BREEZY DURING THE AFTERNOON ALONG AND WEST OF THE
LARAMIE RANGE. TEMPERATURES WEDNESDAY WILL WARM ABOUT 5 DEGREES.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 330 AM MDT MON SEP 7 2015
WEDNESDAY NIGHT/THURSDAY...FLOW ALOFT REMAINS NORTHWEST. WITH
LIMITED LOW AND MID LEVEL MOISTURE...NOT EXPECTING ANY PRECIPITATION.
FRIDAY...NEAR THE SAME OR SLIGHTLY WARMER THAN THURSDAY BASED ON
THICKNESS AND HEIGHT CHANGES. LOW AND MID LEVEL MOISTURE LOOKS TOO
SCANT FOR ANY PRECIPITATION.
SATURDAY...SLOW WARMING TREND CONTINUES AS RIDGING ALOFT BECOMES
MORE PRONOUNCED OVERHEAD. STILL NOT ENOUGH LOW AND MID LEVEL
MOISTURE FOR SHOWER AND THUNDERSTORM FORMATION.
SUNDAY...FLOW ALOFT BECOMES ZONAL...INDUCING EVEN WARMER TEMPERATURES.
STILL DRY WITH LIMITED CLOUD COVER.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 325 AM MDT MON SEP 7 2015
VFR. ISOLATED SHOWERS AND THUNDERSTORMS DEVELOP THIS AFTERNOON AND
EVENING SOUTH OF A LARAMIE TO ALLIANCE LINE. THE STRONGER STORMS
WILL PRODUCE GUSTY AND ERRATIC WIND GUSTS AS WELL AS OCCASIONAL
LIGHTNING.
&&
.FIRE WEATHER...
ISSUED AT 310 AM MDT MON SEP 7 2015
CRITICAL FIRE WEATHER CONDITIONS WILL DEVELOP ONCE AGAIN THIS
AFTERNOON FOR PORTIONS OF EAST AND SOUTH CENTRAL WYOMING. WESTERLY
WINDS WILL FREQUENTLY GUST FROM 25 TO 35 MPH WITH MINIMUM RELATIVE
HUMIDITIES DECREASING TO 10 TO 15 PERCENT. THESE CRITICAL CONDITIONS
WILL DEVELOP ACROSS MOST OF ZONE 302...WESTERN PORTIONS OF ZONE
301...AND NORTHERN PORTIONS OF ZONES 303 AND 308. A COOL FRONT
WILL MOVE ACROSS THE PLAINS THIS EVENING...WITH SLIGHTLY COOLER
TEMPERATURES FOR TUESDAY. THERE IS A SLIGHT CHANCE OF AFTERNOON
AND EVENING SHOWERS AND THUNDERSTORMS ALONG AND EAST OF THE
SOUTHERN LARAMIE RANGE. NEAR CRITICAL FIRE WEATHER CONDITIONS ARE
EXPECTED TUESDAY AND WEDNESDAY FOR AREAS ALONG AND WEST OF THE
LARAMIE RANGE.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR WYZ301>303-308.
NE...NONE.
&&
$$
UPDATE...GCC
SHORT TERM...MAJ
LONG TERM...RUBIN
AVIATION...RUBIN
FIRE WEATHER...MAJ
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1247 AM EDT WED SEP 9 2015
.SYNOPSIS...
HIGH PRESSURE IN THE ATLANTIC WILL CIRCULATE A MOIST SOUTH FLOW
INTO THE FORECAST AREA THROUGH THURSDAY. A WEAK SURFACE TROUGH
WILL ALSO BE NEAR THE AREA. THE PATTERN WILL SUPPORT A CONTINUED
CHANCE OF SHOWERS AND THUNDERSTORMS ESPECIALLY NEAR THE TIMES OF
MAXIMUM HEATING. DRIER AIR WILL BEGIN TO FILTER INTO THE REGION BY
THE BEGINNING OF NEXT WEEK BEHIND A COLD FRONT THAT WILL PUSH
THROUGH OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
THE SHOWER CHANCE SHOULD REMAIN LOW DURING THE REST OF TONIGHT
BECAUSE OF WEAK INSTABILITY. THE HRRR AND RADAR TRENDS SUPPORT
JUST ISOLATED COVERAGE. HIGH LOW-LEVEL MOISTURE AND NOCTURNAL
COOLING SHOULD LEAD TO STRATUS AND FOG DURING THE EARLY MORNING
HOURS. THE TEMPERATURE FORECAST IS ON TRACK. EXPECT LOWS IN THE
LOWER 70S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/...
MODELS REMAIN IN GOOD AGREEMENT THROUGH THIS TIME PERIOD. UPPER
FLOW WILL BE OUT OF THE SOUTHWEST...WITH THE MAIN UPPER TROUGH
STILL OFF TO THE WEST OF THE REGION. CENTER OF THE UPPER RIDGE
WILL BE OVER SOUTHERN FLORIDA. WITH SOUTH TO SOUTHWESTERLY LOW-
LEVEL FLOW EXPECTED TO OCCUR THROUGH THE PERIOD...MOISTURE IS
EXPECTED TO CONTINUE TO INCREASE EACH DAY ACROSS THE REGION.
AFTERNOON TEMPERATURES WILL CONTINUE TO BE IN THE LOWER 90S FOR
MOST AREAS...WITH OVERNIGHT LOWS FALLING INTO THE LOWER 70S. WITH
THE MOISTURE INCREASE EXPECT TO SEE SCATTERED SHOWERS AND
THUNDERSTORMS ESPECIALLY DURING THE AFTERNOONS.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS WITH PREVIOUS DAYS FORECAST RUNS...THE GFS/ECMWF BEGIN TO
DIVERGE WITH THEIR SOLUTIONS THROUGH THE LONGER TERM. BOTH MODELS
DIVE AN UPPER TROUGH SOUTHEASTWARD OUT OF THE UPPER PLAINS STATES
FRIDAY NIGHT INTO SATURDAY...THEN CREATE A CUTOFF LOW ACROSS THE
EASTERN US. IT IS THE DEVELOPMENT AND PLACEMENT OF THIS CUTOFF
THAT THE MODELS DISAGREE WITH OVER THE WEEKEND. THE GFS IS FARTHER
SOUTH AND WEAKER THAN THE ECMWF...WITH THE ECMWF LIFTING THE LOW
QUICKER TOWARDS THE NORTHEAST SUNDAY INTO MONDAY. OBVIOUSLY THE
PLACEMENT AND MOVEMENT OF THE UPPER LOW WILL EVENTUALLY HAVE AN
AFFECT ON THE FINAL PLACEMENT AND MOVEMENT OF THE EXPECTED COLD
FRONT THAT WILL MOVE THROUGH THE REGION THIS WEEKEND.
BOTH MODELS HAVE A PREFRONTAL TROUGH ACROSS THE REGION THROUGH
SATURDAY. WHATEVER THE FINAL TRACK IS FOR THE UPPER LOW...BOTH
MODELS SHOW THE FRONT PUSHING TOWARDS THE COAST SUNDAY...WITH THE
ECMWF BEING FASTER WITH THE TRACK. HAVE LEANED A LITTLE MORE
TOWARDS A BLEND OF THE TWO MODELS FOR NOW. EXPECTING SHOWERS AND
THUNDERSTORMS TO OCCUR EACH AFTERNOON THROUGH SUNDAY...WITH DRYING
FINALLY BEGINNING TO PUSH IN SUNDAY NIGHT.
THE REGION SHOULD BEGIN TO SEE SOME COOLER TEMPERATURES AND DRYING
TO START OFF THE WORK WEEK BEHIND THE COLD FRONTAL PASSAGE.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
ISOLATED SHOWERS CONTINUE JUST OUTSIDE OF THE FORECAST AREA EARLY
THIS MORNING BUT CURRENT RADAR TRENDS SHOW NO THREAT AT THE
TERMINALS AT THIS TIME. HIGH RESOLUTION MODELS ALL INDICATING
IFR/MVFR CONDITIONS DEVELOPING OVERNIGHT. THIS AGREES WITH
PERSISTENCE...SO WILL INCLUDE MORNING STRATUS AND/OR FOG IN ALL TAF
SITES DURING THE PRE-DAWN HOURS THIS MORNING. COULD SEE ISOLATED
SHOWERS OVERNIGHT GIVEN WEAK ISENTROPIC LIFT. CONDITIONS EXPECTED TO
IMPROVE TO VFR AROUND MIDDAY TODAY AS SOUTHWEST WINDS INCREASE TO
AROUND 5 TO 10 KNOTS. SCATTERED CONVECTION WILL RECONVENE DURING THE
AFTERNOON ONCE AGAIN BUT WILL NOT MENTION IN THE TAFS FOR NOW DUE
TO LOW CONFIDENCE IN TIMING AND AREAL COVERAGE.
.EXTENDED AVIATION OUTLOOK...LATE NIGHT/MORNING FOG/STRATUS
POSSIBLE...WITH A CHANCE OF AFTERNOON SHOWERS AND POSSIBLE
THUNDERSTORMS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
99
AREA FORECAST DISCUSSION
National Weather Service Dodge City KS
342 AM CDT WED SEP 9 2015
...Updated for Long Term...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 313 AM CDT WED SEP 9 2015
The main forecast challenge for early this morning is areas of fog,
and or stratus and how dense. Moist weak northeasterly upslope flow
and with clear skies is allowing for good radiational cooling, and
causing areas of ground fog to develop and some stratus. Will carry
areas of fog in most areas this morning, but may need a dense fog
advisory in places especially near and west of Dodge City where the
NAM and the RAP model shows the highest boundary layer relative
humidity. The HRRR model also shows patchy dense fog in the
Garden City area. After the fog burns off by mid morning, expect
clearing skies and highs in the mid 80s. A surface high pressure
ridge will move east while a trough of low pressure develops in
the lee of the Rockies. Light and variable winds this morning
will become southeast to southerly at 10 mph with 10 to 20 mph far
west.
For tonight, expect mainly clear skies. A few thunderstorms could
develop late across the I-70 corridor as a jet streak moves in. Will
carry some small chances for rainfall, towards dawn. Overnight lows
will be in the lower 60s with light southeast winds becoming south
around 8 to 12 mph.
.LONG TERM...(Thursday THROUGH Tuesday)
ISSUED AT 339 AM CDT WED SEP 9 2015
For Thursday, an upper level shortwave trough in northwest flow
aloft will move across western Kansas pushing a cold front to near
Hays to Garden City and Elkhart by late afternoon. Ahead of the cold
front, warmer and moist south winds of 15 to 25 mph, will push highs
to around 90. Most models have thunderstorms developing by afternoon
ahead of the cold front, with a possible MCS (Mesoscale Convective
Complex) developing near and east of Dodge City by late afternoon
and evening. The cold front will continue to push across western
Kansas overnight with numerous thunderstorms developing. Some low
stratus is also suggested towards dawn behind the cold front.
Will carry around 50 percent chances in the afternoon and evening
with lesser chances north of Garden City where dewpoints are much
lower. Forecast instability is around 2000-3000 J/KG, but the NAM
is much higher and with dewpoints in the upper 60s. With 30kt at
mid levels and around 50 to 60kt aloft there could be some severe
thunderstorms with large hail from quarter to half dollar size,
and strong winds over 60 mph.
For Friday into next Tuesday, a dry period is forecast. A large
upper level trough will continue to dig into the Upper Midwest and
Mississippi Valley with much cooler surface high pressure moving
into the Plains. Highs on Friday and Saturday will be in the mid to
upper 70s. As the upper trough moves away from the region Sunday
into Tuesday, a warming trend will move back into the High Plains
with highs in the low 80s on Sunday, then mid to upper 80s on Monday
and Tuesday. Overnight lows will be in the 50s into Sunday morning,
the gradually warm to 60 to 65 degrees on Monday and Tuesday morning.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z Wednesday NIGHT)
ISSUED AT 1201 AM CDT WED SEP 9 2015
Areas of LIFR conditions with ground fog and some low stratus will
prevail through 14-15Z this morning as winds are light northeasterly
and moist upslope along with clear skies and excellent radiational
cooling. As a dome of surface high pressure moves east, winds
shift to light southeasterly with clearing skies after 15Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 85 62 89 60 / 0 10 50 50
GCK 85 61 90 59 / 0 0 30 20
EHA 87 63 91 60 / 10 10 30 30
LBL 86 62 92 61 / 0 10 30 40
HYS 87 61 89 60 / 0 20 30 40
P28 85 63 89 64 / 0 10 20 50
&&
.DDC Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Kruse
LONG TERM...Kruse
AVIATION...Kruse
AREA FORECAST DISCUSSION
National Weather Service Dodge City KS
316 AM CDT WED SEP 9 2015
...Updated for Short Term...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 313 AM CDT WED SEP 9 2015
The main forecast challenge for early this morning is areas of fog,
and or stratus and how dense. Moist weak northeasterly upslope flow
and with clear skies is allowing for good radiational cooling, and
causing areas of ground fog to develop and some stratus. Will carry
areas of fog in most areas this morning, but may need a dense fog
advisory in places especially near and west of Dodge City where the
NAM and the RAP model shows the highest boundary layer relative
humidity. The HRRR model also shows patchy dense fog in the
Garden City area. After the fog burns off by mid morning, expect
clearing skies and highs in the mid 80s. A surface high pressure
ridge will move east while a trough of low pressure develops in
the lee of the Rockies. Light and variable winds this morning
will become southeast to southerly at 10 mph with 10 to 20 mph far
west.
For tonight, expect mainly clear skies. A few thunderstorms could
develop late across the I-70 corridor as a jet streak moves in. Will
carry some small chances for rainfall, towards dawn. Overnight lows
will be in the lower 60s with light southeast winds becoming south
around 8 to 12 mph.
.LONG TERM...(Wednesday NIGHT THROUGH Tuesday)
ISSUED AT 318 PM CDT TUE SEP 8 2015
Some elevated showers and thunderstorms will be possible around
central Kansas late Wednesday night as an area of mid level warm
advection develops. These should diminish Thursday morning as low
level mixing increases. Northwesterly flow aloft will continue on
Thursday. Another shortwave trough will drop out of Alberta into
the Midwest on Thursday. This will push another cold front south
through western Kansas late Thursday afternoon and Thursday night.
Ahead of this front, the boundary layer warms up nicely as low
level winds take on a slightly downslope component. Have bumped up
Thursdays high temperatures 2-4 degrees in most areas.
Widely scattered thunderstorms are expected to develop along and
ahead of the cold front across western Kansas by mid to late
afternoon. The area of storms will gradually shift to the south
and east Thursday night and could linger into Friday before
ending. Highs on Friday will be quite a bit cooler behind the
front. Model guidance suggests highs in the 70s and this may be a
little warm depending on how long any post frontal cloud cover
lingers over the area.
The weekend into early next week should see dry conditions and
moderating temperatures as upper level high pressure redevelops
and moves east across the central and southern Plains.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z Wednesday NIGHT)
ISSUED AT 1201 AM CDT WED SEP 9 2015
Areas of LIFR conditions with ground fog and some low stratus will
prevail through 14-15Z this morning as winds are light northeasterly
and moist upslope along with clear skies and excellent radiational
cooling. As a dome of surface high pressure moves east, winds
shift to light southeasterly with clearing skies after 15Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 85 62 89 60 / 0 10 50 50
GCK 85 61 90 59 / 0 0 30 20
EHA 87 63 91 60 / 10 10 30 30
LBL 86 62 92 61 / 0 10 30 40
HYS 87 61 89 60 / 0 20 30 40
P28 85 63 89 64 / 0 10 20 50
&&
.DDC Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Kruse
LONG TERM...Gerard
AVIATION...Kruse
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1139 PM MDT TUE SEP 8 2015
.UPDATE...
ISSUED AT 539 PM MDT TUE SEP 8 2015
A FEW THUNDERSTORMS HAVE POPPED UP IN N-S ORIENTED INSTABILITY
AXIS ACROSS EASTERN HALF OF CWA. EXPECT CINH TO STEADILY INCREASE
OVER THE NEXT 2 HOURS WHICH WILL ULTIMATELY LIMIT THE COVERAGE
AND DURATION THROUGH THE EARLY EVENING. SEEMS TO BE A PRETTY SHARP
MOISTURE GRADIENT ACROSS THE AREA ATTM WITH DEWPOINTS AROUND 20
DEGREES COOLER IN THE WEST. WITH LIGHT WINDS AND CLEAR SKIES MAY
HAVE TO RETHINK LOW TEMPS...AND HAVE ALSO MODIFIED FOG FORECAST A
BIT TO REFLECT THIS ORIENTATION.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 222 PM MDT TUE SEP 8 2015
WV IMAGERY AND RAP H5 ANALYSIS SHOWS NW FLOW ACROSS CENTRAL ROCKIES
AND OVER OUR CWA ON WESTERN EXTENT OF LARGE SCALE TROUGH. AXIS OF
SUBSIDENCE IS CURRENTLY IN PLACE AS A SHORTWAVE TROUGH IS MOVING
ACROSS CENTRAL KANSAS. AT THE SURFACE HIGH PRESSURE IS BUILDING INTO
OUR CWA FROM THE NORTHERN PLAINS WITH A COLD FRONT THAT MOVED
THROUGH OUR CWA EARLY THIS MORNING EXTENDING FROM NORTHEAST KANSAS
THROUGH SOUTH CENTRAL KANSAS.
TONIGHT...DRY CONDITIONS SHOULD PERSIST THROUGH THE OVERNIGHT PERIOD
WITH SUBSIDENCE PERSISTING THROUGH MOST OF THE NIGHT...AND DEEP DRY
AIR MASS IN PLACE. EARLY IN THE EVENING STEEP LAPSE RATES LEE TROUGH
REBUILDS ALONG KS/CO BORDER OVERNIGHT WITH SOUTHERLY FLOW BRINING
HIGH BL MOISTURE IN PLACE. TREND IN GUIDANCE HAS BEEN TO TO SHOW
BETTER MIXING AND BL RH STAYING UP LIMITING FOG POTENTIAL. NAM AND
RAP DO STILL SHOW SOME REDUCED VISIBILITIES AND I FELT COMFORTABLE
KEEPING MENTION IN FORECAST FOR NOW.
WEDNESDAY...A QUICK MOVING/WEAK SHORTWAVE TROUGH WILL ROTATE THROUGH
NW FLOW JUST NORTH OF OUR CWA. DRY LAYER IN PLACE LOWERS OVERALL
CONFIDENCE IN COVERAGE...HOWEVER GUIDANCE IS SHOWING INITIATION
EITHER UPSTREAM OR ALONG SURFACE TROUGH AND TRACKING EAST ACROSS THE
NORTHERN HALF OF OUR CWA. IF A CELL WERE TO DEVELOP ML CAPE VALUES
AROUND 2000 J/KG AND EFFECTIVE SHEAR VALUES AROUND 35KT COULD
SUPPORT A LIMITED SEVERE THREAT. IM JUST NOT SURE IF ANYTHING WILL
EVEN DEVELOP CONSIDERING THE DRY AIR MASS IN PLACE. I KEPT SLIGHT
CHANCE POPS IN THE AFTERNOON...COVERING POTENTIAL.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 255 PM MDT TUE SEP 8 2015
SEVERAL SHORT WAVE TROUGHS MOVE ACROSS THE CENTRAL HIGH PLAINS
REGION WEDNESDAY NIGHT...THURSDAY NIGHT...AND FRIDAY EVENING. THE
UPPER PATTERN BECOMES MORE AMPLIFIED AS THE SHORT WAVE TROUGHS
DIVE INTO THE BASE OF THE MAIN UPPER TROUGH POSITIONED OVER THE
MISSISSIPPI VALLEY REGION AS THE UPPER RIDGE AMPLIFIES OVER THE
WESTERN UNITED STATES THURSDAY THROUGH FRIDAY NIGHT AND
TRANSITIONS EASTWARD OVER THE ROCKIES AND HIGH PLAINS SATURDAY
NIGHT.
WITH A SURFACE TROUGH/FRONTAL BOUNDARY REMAINING IN THE VICINITY
OF THE FORECAST AREA THESE SHORT WAVE TROUGHS TRANSITIONING THE
REGION WILL HELP ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
DEVELOP EACH DAY FROM LATE WEDNESDAY THROUGH EARLY FRIDAY. BY LATE
FRIDAY THE FRONTAL BOUNDARY HAS PUSHED SOUTH OF THE REGION AND
SURFACE HIGH PRESSURE MOVES INTO THE AREA. TEMPERATURES WILL WARM
THROUGH THURSDAY AHEAD OF THE FRONT WITH HIGH TEMPERATURES ONLY
EXPECTED TO REACH IN TO THE 70S ON FRIDAY. TEMPERATURES WILL
REBOUND QUICKLY THROUGH THE WEEKEND AND INTO NEXT WEEK AS
SOUTHERLY NEAR SURFACE FLOW RETURNS AND THE REGION REMAINS UNDER
WEAK RIDGING THROUGH THE WEEKEND AS THE UPPER PATTERN UNDERGOES A
TRANSITION TO A RIDGE OVER THE EASTERN HALF OF THE UNITED STATES
WHILE THE NEXT SIGNIFICANT LONG WAVE TROUGH DEEPENS OVER THE
WESTERN UNITES STATES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1136 PM MDT TUE SEP 8 2015
POTENTIAL PERIOD OF IFR VISIBILITIES OVERNIGHT LOOKS ON TRACK AS
LIGHT EASTERLY WINDS SLOWLY ADVECTING INCREASING TDS INTO THE
AREA...WITH SFC TEMPS BELOW DOWNSTREAM DEWPOINTS IN SEVERAL AREAS.
SATELLITE FOG PRODUCT STARTING TO PICK UP ON SOME LOW STRATUS AS
WELL WITH HLC SEEING CLOUD HEIGHTS AROUND 2000 FEET. THIS LOOKS
RATHER SPOTTY FOR NOW AND PLAN TO KEEP MAIN FOCUS OF TAFS
INCREASING THREAT FOR FOG.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JRM
SHORT TERM...DR
LONG TERM...LOCKHART
AVIATION...JRM
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
250 AM EDT WED SEP 9 2015
.SYNOPSIS...
HIGH PRESSURE WILL SLIDE OFF THE MID ATLANTIC COAST TONIGHT THROUGH
WEDNESDAY. A COLD FRONT APPROACHES FROM THE NORTHWEST WEDNESDAY...AND
SETTLES INTO THE REGION THURSDAY. THE FRONT STALLS OVER NORTH
CAROLINA FRIDAY INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
UPDATE...SHOWERS ACROSS INTERIOR NE NC ARE FINALLY TAPERING OFF
LATE THIS EVENING AND A LULL IN ACTIVITY IS EXPECTED DURING THE
REST OF THE EVENING AND EARLY OVERNIGHT HOURS.
PREVIOUS DISCUSSION...PER LATEST RAP GUIDANCE...WEAK VORT MAX
LIFTS NEWD OVER ERN VA TONIGHT. HI-RES GUIDANCE INDICATES THE
WARM/MOIST AND MODESTLY UNSTABLE AIR MASS MAY PRODUCE SOME
ISOLATED SHOWERS OVERNIGHT ACROSS CENTRAL AND ERN VA AS THE VORT
LIFTS...ESPECIALLY OVER THE BAY AND ERN SHORE. HOWEVER...
CONFIDENCE IS NOT HIGH ATTM...SO WILL LEAVE SLIGHT CHANCE WORDING.
A PARTLY CLOUDY SKY AND DISPERSAL WILL LIMIT FOG DEVELOPMENT
TONIGHT...BUT WARM/SOUPY AIR MASS SHOULD BE ENOUGH FOR PATCHY FOG
IN AREAS THAT RECEIVED RAINFALL EARLIER TODAY. A MILD TONIGHT
AHEAD WITH LOWS IN THE LOW 70S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY/...
UPPER TROUGH DIGS OVER THE GREAT LAKES REGION WEDS AND
THU...RESULTING IN HEIGHT FALLS OVER THE MID-ATLANTIC REGION. AN
ASSOCIATED COLD FRONT IS EXPECTED TO REACH THE OHIO VALLEY BY WEDS
AFTERNOON. LEE/THERMAL TROUGH DEVELOPS OVER THE PIEDMONT IN
ADVANCE OF THE FRONT WEDS AFTERNOON. INCREASING SW FLOW WILL
ADVECT DEEP LAYERED MOISTURE INTO THE REGION...WITH PWATS PROGGED
AOA 2 INCHES (+1 TO +2 STD DEV). WHILE THE MAIN SHEARING VORT
ENERGY REMAINS OVER THE OHIO VALLEY...WEAK PERTURBATIONS IN THE SW
FLOW WILL PROVIDE SUBTLE FORCING FOR ASCENT OVER THE LOCAL AREA.
THETA-E ADVECTION AND DEWPOINTS IN THE LOW 70S WILL RESULT IN
BETTER INSTABILITY...WITH MLCAPE ~1500 J/KG. HAVE FAVORED THE
PIEDMONT INTO CENTRAL AND EAST CENTRAL VA FOR 30-40 PCT POPS.
WARMER TEMPS ALOFT ACROSS THE SE WILL LIMIT OVERALL COVERAGE...SO
HAVE CAPPED AT 30 PCT. EFFECTIVE SHEAR PROGGED AROUND 15 TO 20 KT
MAY RESULT IN SLIGHT BETTER ORGANIZATION...BUT SEVERE WEATHER IS
NOT ANTICIPATED. WARM AND HUMID CONDITIONS PERSIST...WITH HIGHS
FORECAST IN THE UPPER 80S TO AROUND 90 (MID 80S ALONG THE COAST).
SLIGHT CHANCE TO CHANCE POPS WILL BE MAINTAINED THROUGH WEDNESDAY
NIGHT. MILD AGAIN...WITH LOWS IN THE LOW/MID 70S.
THE FLOW CONTINUES TO AMPLIFY OVER THE GREAT LAKES AND ERN CONUS
THURSDAY AS SHORTWAVE ENERGY REACHES THE MID-ATLANTIC STATES. SFC
LOW DEVELOPS ALONG THE FRONT THU MORNING...LIFTING OVER NRN VA
INTO THE DELMARVA THU AFTERNOON AND EVENING. EXPECT
WIDESPREAD...BENEFICIAL RAINFALL THURSDAY AFTERNOON. A WARM/MOIST
AIR MASS REMAINS IN PLACE...BUT INSTABILITY WILL BE LIMITED DUE TO
CLOUD COVER AND PRECIP. HAVE RETAINED LIKELY POPS ACROSS ALL BUT
THE FAR SE LOCAL AREA. LACK OF ORGANIZED FORCING AND ANOMALOUS
FLOW WILL KEEP OVERALL QPF AOB ONE HALF OF AN INCH. WEAK FLOW AND
MBE/CORFIDI VECTORS FAVOR LOCALLY HIGHER AMOUNTS. CLOUDS/PRECIP
AND HEIGHT/THICKNESS FALLS YIELD TEMPS RANGING FROM THE LOW 80S NW
TO UPPER 80S SE.
THE FRONT STALLS ALONG THE COAST THU NIGHT AND FRI IN SWLY FLOW
ALOFT. BEST MOISTURE AND SHORTWAVE ENERGY LOCATES OVER THE COASTAL
PLAIN...AND WILL RETAIN CHANCE POPS ACROSS SOUTHERN VA AND SE
VA/NE NC. MORE SEASONABLE CONDITIONS EXPECTED FRI WITH HIGHS IN
THE LOW TO MID 80S AND DEWPOINTS COOLING INTO THE LOW 60S NW TO
UPPER 60S SE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
MODELS CONT TO STRUGGLE WITH A SOLN TO JUST HOW FAR EAST THE FRNTL
BNDRY GETS THIS WEEKEND AS IT APPRCHS THE OFFSHORE RIDGE. CONSENSUS
IS THAT IT STALLS RIGHT ALONG THE COAST AS SVRL WAVES OF LOW PRS
MOVE NE ALONG IT. IN ADDITION...A RTHR POTENT UPR LVL SYSTM
PROGGED TO DIVE SE FROM THE GT LAKE RGN LATER THIS WEEKEND. GFS
STILL FRTHER SOUTH...BUT IT IS STARTING TO COME IN LINE WITH THE
ECMWF SOLN OF SWING THE UPR LVL LOW NORTH OF FA WITH MOST OF THE
ENERGY FROM THE VA MTS ON NORTH. APPEARS HIGH PRS MOVG EAST FROM
NATIONS MID SECTION WILL BE STRNG ENUF TO PUSH THE ENTIRE SYSTM
OFFSHORE ERLY NEXT WK.
GIVEN THE ABOVE UNCERTAINTY...WILL KEEP A CONSISTENT FCST AND LEAN
MORE TOWARD A ECMWF SOLN. KEPT CHC POPS FRI NITE THRU SUN NITE
(HIGHEST POPS ALONG THE COAST AND MENTION THUNDER IN THE IN AFTN AND
EVE). DRY MON/TUE. A COOLING TREND THRU THE PRD. HIGHS SAT 80-
85...COOLER AT THE BEACHES. LOWS 60-65. HIGHS SUN/MON 75-80. LOWS
M50S-L60S. HIGHS TUE U70S-L80S.
&&
.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
06Z TAF PERIOD STARTS OUT WITH VFR CONDS TRANSITIONING TO MVFR/IFR
IN SPOTS WITH LIGHT WINDS AND SFC HI PRES IN THE AREA. INCLUDED
THIS IN ALL TAFS EXCEPT KORF. CONDS WILL IMPROVE BY MID MORNG
EVERYWHERE. THERE WILL BE A CHANCE OF SHRAS/TSTMS FM TDA THRU THE
WEEKEND AS A COLD FRNT APPROACHES FM THE W AND STALLS IN THE
VICINITY.
&&
.MARINE...
NO HEADLINES XPCT AS HIGH PRS MOVES OFFSHORE RESULTING IN A RETURN
SLY FLOW THRU THURSDAY. ONCE AGAIN...HIGH RES DATA SUGGESTS SOME
CHANNELING UP THE BAY AT NIGHT...SO KEPT SPEEDS AOB 15 KTS FOR
NOW. COLD FRONT APPRCHS THE AREA THURSDAY AFTN THEN CROSSES THE
WTRS THURSDAY NIGHT BEFORE STALLING JUST OFF THE COAST FRIDAY.
LACK OF CAA BEHIND THE FRONT WILL KEEP SUB-SCA CNDTNS INTO FRIDAY.
LOCATION OF FRONT INTO THE WEEKEND WILL BE KEY TO THE FCST. RIGHT
NOW THE BNDRY LOOKS TO STRADDLE THE COAST KEEPING WNDS IN A GNRL
WEST DRCTN AT SPEEDS ARND 10 KTS.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...AJZ/SAM
NEAR TERM...AJZ/BMD/SAM
SHORT TERM...AJZ/SAM
LONG TERM...MPR
AVIATION...MAS
MARINE...MPR
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
320 AM EDT WED SEP 9 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 417 PM EDT TUE SEP 8 2015
WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A MID/UPPER LEVEL LOW
SPINNING OVER MANITOBA. ONE SHORTWAVE IS LIFTING NE ACROSS NRN
ONTARIO TO THE N OF LAKE OF THE WOODS. TAIL END OF THAT WAVE IS
GENERATING SHRA/TSRA N OF THE MN/ONTARIO BORDER. CLOSER TO HOME...
SHORTWAVE THAT LIFTED ACROSS WI TOWARD ERN UPPER MI BROUGHT
WIDESPREAD SHRA/ISOLD TSTMS ACROSS ALL BUT FAR WRN UPPER MI TODAY.
THAT ACTIVITY IS MOVING OUT QUICKLY NOW. TO THE W...IT APPEARS THAT
THERE ARE 2 BOUNDARIES THAT STILL NEED TO BE WATCHED FOR NEW
CONVECTIVE DEVELOPMENT. THE FIRST IS LAKE BREEZE BOUNDARY RUNNING
FROM THE E SIDE OF THE KEWEENAW TO CNTRL GOGEBIC COUNTY...AND THE
OTHER IS THE COLD FRONT MOVING ACROSS THE WRN PART OF LAKE SUPERIOR.
MOSTLY FOLLOWED RECENT RADAR TRENDS TO MOVE LINGERING WIDESPREAD
SHRA OUT OF THE ERN FCST AREA OVER THE NEXT FEW HRS. HELD LOW POPS
BACK TO THE W AHEAD OF THE TWO AFOREMENTIONED BOUNDARIES. LATEST SPC
MESOANALYSIS HAS MLCAPES UP TO AROUND 250J/KG OR SO AND SBCAPE TO
AROUND 500J/KG AHEAD OF THE BOUNDARIES. WITH CU BUILDING UP PER VIS
SATELLITE IMAGERY...CAN`T RULE OUT ISOLD/SCT SHRA DEVELOPMENT...
PERHAPS A TSTM. WHATEVER HAPPENS...PCPN RISK WILL BE DONE BY LATE
EVENING AS COLD FRONT SWEEPS ACROSS THE AREA. MUCH DRIER AIR MASS
SURGING INTO THE AREA WILL FINALLY BRING AN END TO THE UNSEASONABLY
LONG STRETCH OF HIGH DWPTS FOR THIS TIME OF YEAR. UPSTREAM IN NRN
MN...SFC DWPTS HAVE FALLEN THRU THE 40S WITH EVEN SOME 30S SHOWING
UP. EXPECT CLEARING SKIES FROM THE W TONIGHT. IF THERE IS ANY FOG ON
LAKE SUPERIOR...IT WILL AFFECT THE ERN SHORELINE AREAS BEFORE BEING
SWEPT CLEAR BY THE MUCH DRIER AIR MASS. IT WILL BE THE COOLEST NIGHT
IN WELL OVER A WEEK. MIN TEMPS SHOULD FALL INTO THE MID 40S OVER THE
INTERIOR W HALF AND MOSTLY LOW/MID 50S ELSEWHERE.
DRY AIR MASS WILL SET UP A NICE WED UNDER PLENTY OF SUNSHINE. DWPTS
WILL BE LOW...MOSTLY IN THE 40S...WITH HIGH TEMPS IN THE UPPER 60S
TO MID 70S...WARMEST IN THE AREAS THAT SEE DOWNSLOPING UNDER A
WESTERLY WIND. SPEAKING OF WHICH...WINDS SHOULD BE GUSTY INTO THE 20
TO 30 MPH RANGE...ESPECIALLY OVER THE NW FCST AREA.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 320 AM EDT WED SEP 9 2015
NAM SHOWS A BROAD 500MB TROUGH OVER THE UPPER GREAT LAKES AND
EASTERN U.S. WITH A RIDGE IN THE WESTERN U.S. THIS TROUGH DEEPENS
WITH TIME AND THE TROUGH AXIS MOVES ACROSS THE UPPER GREAT LAKES ON
FRI. NAM SHOWS SOME 850-500 MB Q-VECTOR CONVERGENCE MOVING ACROSS
THE AREA ON THU WITH DEEPER MOISTURE ACROSS THE SOUTHERN HALF OF THE
CWA.
LAKE EFFECT COMES INTO PLAY THIS FORECAST PERIOD AS OPEN LAKE
TEMPERATURES RANGE FROM 12C TO 15C AND 850 MB TEMPERATURES DROP TO
2C TO 4C THU NIGHT AND FRI AND THIS IS ENOUGH DELTA-T COMBINED WITH
SOME WEAK 850-500 MB Q-VECTOR CONVERGENCE TO AT LEAST KEEP IN SLIGHT
CHANCE TO LOW CHANCE POPS THU NIGHT AND FRI AND ALSO A BIT MORE
CLOUD COVER DUE TO LAKE EFFECT CLOUDS. FOR THU...KEPT HIGHEST POPS
IN THE SOUTH WITH BEST MOISTURE IN THAT AREA AND DRY IN THE FAR
NORTHERN CWA. OTHERWISE...DID NOT MAKE TOO MANY CHANGES TO THE GOING
FORECAST OR FOR TEMPERATURES.
IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB TROUGH OVER THE UPPER
GREAT LAKES EMBEDDED IN A DEEP TROUGH OVER THE EASTERN U.S. 12Z SAT
WITH A RIDGE OVER THE WESTERN U.S. THIS TROUGH MOVES SLOWLY EAST 12Z
SUN WITH THE RIDGE OVER THE WESTERN U.S. GETTING FLATTENED WITH
TIME. BY 12Z MON...RIDGE IS FLATTENED ENOUGH TO CAUSE ZONAL FLOW
OVER THE UPPER GREAT LAKES MON. A TROUGH MOVES ONTO THE WEST COAST
12Z TUE WITH ZONAL FLOW CONTINUING OVER THE UPPER GREAT LAKES ON
TUE. TEMPERATURES WILL STAY ABOVE NORMAL THIS FORECAST PERIOD AND
WILL GO DRY SAT THROUGH SUN NIGHT AND THEN A WEAK COLD FRONT STALLS
OUT OVER THE AREA FOR MON INTO TUE WITH LIMITED MOISTURE AVAILABLE
TO WORK WITH.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 119 AM EDT WED SEP 9 2015
EXPECT VFR CONDITIONS THROUGH WEDNESDAY. MID CLOUDS INCREASE ON
WEDNESDAY EVENING WITH SOME RAIN POSSIBLE LATER WEDNESDAY NIGHT.
GUSTY WINDS ARE EXPECTED AT ALL THE TAF SITES ON WEDNESDAY DURING
PEAK MIXING OF THE DAY. STRONGEST WIND GUSTS OVER 25 KTS WILL BE AT
THE MORE EXPOSED KCMX LOCATION.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 417 PM EDT TUE SEP 8 2015
FIRST UP...IF THERE IS ANY FOG ON LAKE SUPERIOR...IT WILL BE SWEPT
OFF THE ERN PORTION OF THE LAKE TONIGHT AS STRENGTHENING W WINDS
BEHIND A PASSING COLD FRONT USHER IN A MUCH DRIER AIR MASS TONIGHT.
INCOMING PRES RISES WILL HELP BOOST W WIND GUSTS TO 25-30KT FOR A
TIME AFTER FRONTAL PASSAGE. DURING WED...W WINDS OF 15-25KT WILL
GENERALLY BE THE RULE...BUT OVER CNTRL LAKE SUPERIOR AND IN
PARTICULAR AROUND THE TIP OF THE KEWEENAW PENINSULA...WINDS OF 20-
30KT ARE EXPECTED. LIGHTER WINDS OF 10-20KT ARE EXPECTED FOR WED
NIGHT/THU. ARRIVAL OF A COLDER AIR MASS AHEAD OF APPROACHING SFC
HIGH PRES WILL LEAD TO A PERIOD OF STRONGER WINDS OF 15-30KT AGAIN
THU NIGHT INTO AT LEAST FRI MORNING...STRONGEST OVER THE E HALF.
WINDS WILL SLOWLY DIMINISH W TO E FRI AFTN THRU SAT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...07
AVIATION...JLA
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
119 AM EDT WED SEP 9 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 417 PM EDT TUE SEP 8 2015
WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A MID/UPPER LEVEL LOW
SPINNING OVER MANITOBA. ONE SHORTWAVE IS LIFTING NE ACROSS NRN
ONTARIO TO THE N OF LAKE OF THE WOODS. TAIL END OF THAT WAVE IS
GENERATING SHRA/TSRA N OF THE MN/ONTARIO BORDER. CLOSER TO HOME...
SHORTWAVE THAT LIFTED ACROSS WI TOWARD ERN UPPER MI BROUGHT
WIDESPREAD SHRA/ISOLD TSTMS ACROSS ALL BUT FAR WRN UPPER MI TODAY.
THAT ACTIVITY IS MOVING OUT QUICKLY NOW. TO THE W...IT APPEARS THAT
THERE ARE 2 BOUNDARIES THAT STILL NEED TO BE WATCHED FOR NEW
CONVECTIVE DEVELOPMENT. THE FIRST IS LAKE BREEZE BOUNDARY RUNNING
FROM THE E SIDE OF THE KEWEENAW TO CNTRL GOGEBIC COUNTY...AND THE
OTHER IS THE COLD FRONT MOVING ACROSS THE WRN PART OF LAKE SUPERIOR.
MOSTLY FOLLOWED RECENT RADAR TRENDS TO MOVE LINGERING WIDESPREAD
SHRA OUT OF THE ERN FCST AREA OVER THE NEXT FEW HRS. HELD LOW POPS
BACK TO THE W AHEAD OF THE TWO AFOREMENTIONED BOUNDARIES. LATEST SPC
MESOANALYSIS HAS MLCAPES UP TO AROUND 250J/KG OR SO AND SBCAPE TO
AROUND 500J/KG AHEAD OF THE BOUNDARIES. WITH CU BUILDING UP PER VIS
SATELLITE IMAGERY...CAN`T RULE OUT ISOLD/SCT SHRA DEVELOPMENT...
PERHAPS A TSTM. WHATEVER HAPPENS...PCPN RISK WILL BE DONE BY LATE
EVENING AS COLD FRONT SWEEPS ACROSS THE AREA. MUCH DRIER AIR MASS
SURGING INTO THE AREA WILL FINALLY BRING AN END TO THE UNSEASONABLY
LONG STRETCH OF HIGH DWPTS FOR THIS TIME OF YEAR. UPSTREAM IN NRN
MN...SFC DWPTS HAVE FALLEN THRU THE 40S WITH EVEN SOME 30S SHOWING
UP. EXPECT CLEARING SKIES FROM THE W TONIGHT. IF THERE IS ANY FOG ON
LAKE SUPERIOR...IT WILL AFFECT THE ERN SHORELINE AREAS BEFORE BEING
SWEPT CLEAR BY THE MUCH DRIER AIR MASS. IT WILL BE THE COOLEST NIGHT
IN WELL OVER A WEEK. MIN TEMPS SHOULD FALL INTO THE MID 40S OVER THE
INTERIOR W HALF AND MOSTLY LOW/MID 50S ELSEWHERE.
DRY AIR MASS WILL SET UP A NICE WED UNDER PLENTY OF SUNSHINE. DWPTS
WILL BE LOW...MOSTLY IN THE 40S...WITH HIGH TEMPS IN THE UPPER 60S
TO MID 70S...WARMEST IN THE AREAS THAT SEE DOWNSLOPING UNDER A
WESTERLY WIND. SPEAKING OF WHICH...WINDS SHOULD BE GUSTY INTO THE 20
TO 30 MPH RANGE...ESPECIALLY OVER THE NW FCST AREA.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 414 PM EDT TUE SEP 8 2015
THE UPPER TROUGH THAT IS CURRENTLY MOVING EAST ACROSS SOUTH CENTRAL
CANADA AND THE UPPER MISSISSIPPI VALLEY WILL MOVE INTO THE UPPER
GREAT LAKES OVER THE NEXT 12 HOURS AND THEN AMPLIFY OVER THE REGION
HEADING INTO THE END OF THE WORK WEEK AS A WAVE CURRENTLY MOVING
INTO BRITISH COLUMBIA ROTATES THROUGH. THIS SETUP WILL LEAD TO
GENERALLY BELOW NORMAL TEMPERATURES INTO THE START OF THE WEEKEND
WITH PERIODS OF SHOWERS.
AFTER A DRY START TO THE LONG TERM PERIOD ON WEDNESDAY EVENING
(DUE TO AN EXISTING HIGH PRESSURE RIDGE)...A WEAK SURFACE TROUGH
WILL MOVE EAST ACROSS THE UPPER MISSISSIPPI VALLEY AND INTO THE
GREAT LAKES REGION LATER WEDNESDAY NIGHT AND THURSDAY. THIS WILL BE
IN RESPONSE TO THE SHORTWAVE CURRENTLY MOVING INTO BRITISH COLUMBIA
THAT WILL BE ROUNDING THE BASE OF THE UPPER TROUGH. SHOWERS ARE
EXPECTED TO DEVELOP IN SOUTHERN MINNESOTA AND WESTERN WISCONSIN
ON WEDNESDAY NIGHT AND THEN SPREADING EAST-NORTHEAST INTO PORTIONS
OF UPPER MICHIGAN. MODELS ARE DIFFERING ON THE NORTHWEST EXTENT OF
THE SHOWERS...LARGELY DUE TO THE TRACK OF THE SHORTWAVE WITH HALF
TRACKING IT ACROSS NORTHERN WISCONSIN (PUSHING PRECIP FARTHER NORTH)
AND THE OTHER HALF TRACK IT MORE ACROSS SOUTHERN WISCONSIN (AND HAS
PRECIP ONLY BRUSHING THE SOUTHERN THIRD OF THE AREA) ON THURSDAY.
DID SEE A SOUTHEAST TREND WITH THE 12Z ECMWF...WHICH IS MORE IN LINE
WITH THE 12Z GFS/GEM...SO WHILE CONFIDENCE IS LOW...FELT IT WAS
REASONABLE TO TREND THE CHANCE POPS FARTHER TO THE SOUTHEAST AND
MORE OVER THE SOUTH CENTRAL AND ALONG THE LAKE MICHIGAN SHORELINE.
THOSE SHOWERS WILL DEPART ON THURSDAY NIGHT AS THE SHORTWAVE AND
SURFACE TROUGH DEPARTS. THIS WILL ALLOW MUCH COLDER AIR TO SURGE
SOUTH ACROSS THE AREA THURSDAY NIGHT INTO FRIDAY...WITH 850MB TEMPS
FALLING TO 1-2C. SINCE LAKE SUPERIOR TEMPERATURES ARE IN THE 12-18C
RANGE...EXPECT SOME POTENTIAL OF LAKE EFFECT/ENHANCED RAIN FOR
THURSDAY NIGHT INTO FRIDAY. MODELS SHOWING DECENT MOISTURE BELOW
THE INVERSION AROUND 750MB...SO HAVE CHANCE POPS FOR THE FAVORED
NORTHERLY WIND LOCATIONS NEAR LAKE SUPERIOR DURING THAT TIME.
WILL LIKELY NEED TO TREND POPS UP FURTHER IF THE LATEST MODEL
TRENDS CONTINUE. IN ADDITION...THAT COLD AIR AND DECENT CLOUD COVER
FOR MUCH OF THE DAY ON FRIDAY WILL KEEP HIGHS IN THE 50S.
A SURFACE HIGH OFF TO THE WEST IN THE DAKOTAS WILL TRY TO PUSH A
SURFACE RIDGE INTO THE AREA ON FRIDAY...BUT IT WILL LIKELY REALLY
ARRIVE ON SATURDAY AS THE UPPER TROUGH BEGINS TO SHIFT EAST. DRIER
AIR ASSOCIATED WITH THE HIGH WILL LEAD TO DECREASING CLOUDS FROM
WEST TO EAST ON FRIDAY AFTERNOON...WITH CLEAR SKIES REMAINING IN
PLACE THROUGH MUCH OF THE WEEKEND. SATURDAY WILL REMAIN BELOW
NORMAL FOR HIGHS...BUT WITH THE UPPER RIDGE AXIS SHIFTING EAST FROM
THE DAKOTAS AND INTO THE UPPER GREAT LAKES REGION FOR SUNDAY AND
MONDAY...EXPECT HIGHS TO RISE BACK UP TO NORMAL OR EVEN SLIGHTLY
ABOVE NORMAL VALUES. WILL NEED TO WATCH THE EVOLUTION OF THE UPPER
TROUGH JUST TO THE EAST-SOUTHEAST OF THE AREA FOR SUNDAY/MONDAY
TIME FRAME...AS THERE ARE SOME HINTS OF IT ROTATING BACK NORTHWEST
AS THE UPPER RIDGE REMAINS FARTHER WEST. THAT WOULD LEAD TO COOLER
AND BETTER OPPORTUNITIES FOR RAIN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 119 AM EDT WED SEP 9 2015
EXPECT VFR CONDITIONS THROUGH WEDNESDAY. MID CLOUDS INCREASE ON
WEDNESDAY EVENING WITH SOME RAIN POSSIBLE LATER WEDNESDAY NIGHT.
GUSTY WINDS ARE EXPECTED AT ALL THE TAF SITES ON WEDNESDAY DURING
PEAK MIXING OF THE DAY. STRONGEST WIND GUSTS OVER 25 KTS WILL BE AT
THE MORE EXPOSED KCMX LOCATION.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 417 PM EDT TUE SEP 8 2015
FIRST UP...IF THERE IS ANY FOG ON LAKE SUPERIOR...IT WILL BE SWEPT
OFF THE ERN PORTION OF THE LAKE TONIGHT AS STRENGTHENING W WINDS
BEHIND A PASSING COLD FRONT USHER IN A MUCH DRIER AIR MASS TONIGHT.
INCOMING PRES RISES WILL HELP BOOST W WIND GUSTS TO 25-30KT FOR A
TIME AFTER FRONTAL PASSAGE. DURING WED...W WINDS OF 15-25KT WILL
GENERALLY BE THE RULE...BUT OVER CNTRL LAKE SUPERIOR AND IN
PARTICULAR AROUND THE TIP OF THE KEWEENAW PENINSULA...WINDS OF 20-
30KT ARE EXPECTED. LIGHTER WINDS OF 10-20KT ARE EXPECTED FOR WED
NIGHT/THU. ARRIVAL OF A COLDER AIR MASS AHEAD OF APPROACHING SFC
HIGH PRES WILL LEAD TO A PERIOD OF STRONGER WINDS OF 15-30KT AGAIN
THU NIGHT INTO AT LEAST FRI MORNING...STRONGEST OVER THE E HALF.
WINDS WILL SLOWLY DIMINISH W TO E FRI AFTN THRU SAT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...JLA
MARINE...ROLFSON
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1202 AM CDT WED SEP 9 2015
.UPDATE:
Issued at 850 PM CDT Tue Sep 8 2015
Have updated forecast to pull precip further S as cdfnt continues
to slowly move swd. Precip along the fnt shud fill in a little
more to the E over night. Overall, have trended twd the RAP soln
which keeps most of the precip across sern portions of the CWA by
sunrise Wed morning.
&&
.SHORT TERM: (Through Late Tonight)
Issued at 210 PM CDT Tue Sep 8 2015
Cold front really struggling to make too much progress south today
and is currenlty aligned from near Kansas City to the Quad Cities.
Precipitation trends remain the focus for the forecast.
Area of showers and thunderstorms continue to slowly progress south
on outflow from last nights convection that occurred to our
northwest. This is well out ahead of the front and away from any
deep layer flow aloft so severe chances have been largely removed.
More convection is forming back across central Kansas and think this
wave of precipitation will replace ongoing activity overnight and
into tomorrow morning.
CVKING
.LONG TERM: (Wednesday through Next Tuesday)
Issued at 210 PM CDT Tue Sep 8 2015
Upper level trof axis, currently extending from the upper Midwest
to the central Plains, will move east over the next 24 hours
forcing the cold front south through the area and ending the
threat of precipiation from northwest to southeast.
Temperatures should cool to near normal values Wednesday and
Thursday before a stronger cold front arrives Thursday night and
Firday. Have some chance PoPs with the front, but think focus may
remain west of the CWA. Autumn temperatures arrive for the weekend
with highs in the 70s and lows dipping into the upper 40s and lower
50s.
CVKING
&&
.AVIATION: (For the 06z TAFs through 06z Wednesday Night)
Issued at 1157 PM CDT Tue Sep 8 2015
Cold front is still approaching KCOU, and is south of KUIN. Broken
line of SHRA/TSRA continues to fire along it and different waves
should continue to develop and dissipate over the next several
hours. Low CIGs continue to develop with expanded area of IFR now
looking likely for STL metro and back to KCOU and have placed in
the 06z TAF issuance for overnight and Wednesday morning. These
IFR CIGs will then be slow to pull out, with non-VFR CIGs
expected well into the day Wednesday with diurnal enhancements as
it becomes more of a broken cumulus cloud field. Eventually
clearing is anticipated by Wednesday evening. Winds will be light
throughout, becoming northerly behind front.
Specifics for KSTL: conditions on their way down with IFR now
expected later tonight and to continue into Wednesday morning
before gradual improvement, with MVFR CIGs hanging on into the
afternoon, with a return to VFR conditions is expected by
nightfall Wednesday night.
TES
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
324 AM EDT WED SEP 9 2015
.SYNOPSIS...
SUMMERLIKE HEAT WILL BE IN PLACE TODAY WITH A FEW STRAY
THUNDERSTORMS. CLOUDS AND RAIN CHANCES THEN INCREASE LATE IN THE
WEEK WITH THE SLOW APPROACH OF A COLD FRONT. THIS BOUNDARY MAY NOT
PUSH THROUGH UNTIL MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM WEDNESDAY...SURFACE HIGH PRESSURE NORTH OF BERMUDA WILL
PROVIDE A WARM AND HUMID AIRMASS TO THE CAROLINAS TODAY STRAIGHT OUT
OF THE BAHAMAS. 850 MB TEMP EXPECTED TO HOVER AROUND +18C IS NEAR
THE 95TH PERCENTILE FOR CLIMATOLOGICAL READINGS THIS TIME OF YEAR AT
CHS. AS A RESULT WE SHOULD SEE HIGH TEMPERATURES RISE INTO THE LOWER
90S INLAND WITH UPPER 80S ON THE COAST. THIS IS STILL 5 OR MORE
DEGREES AWAY FROM RECORDS. WITH DEWPOINTS REMAINING IN THE LOWER TO
MID 70S HEAT INDEX VALUES SHOULD REACH 100 DEGREES ACROSS PARTS OF
THE PEE DEE REGION.
AN UPPER DISTURBANCE CURRENTLY MOVING NORTHEASTWARD FROM GEORGIA
INTO SOUTHERNMOST SOUTH CAROLINA IS HELPING SUPPORT A CLUSTER OF
THUNDERSTORMS NEAR CHARLESTON. THIS DISTURBANCE SHOULD MOVE ALONG
THE SOUTH CAROLINA COAST AFTER SUNRISE...REACHING SE NORTH CAROLINA
BY LATE THIS MORNING. HIGH RES MODELS INCLUDING THE NSSL WRF...THE
LATEST SEVERAL HRRR RUNS...AND THE ARW AND NMM VERSIONS OF THE WRF
ALL SUPPORT THE IDEA OF CONVECTION BECOMING MORE WIDESPREAD ACROSS
SE NORTH CAROLINA AROUND 15Z (11 AM) AS THE UPPER DISTURBANCE
ENCOUNTERS AN UNCAPPED AIRMASS WITH SURFACE-BASED CAPE IN EXCESS OF
2000 J/KG. I HAVE INCREASED POPS TO 40-60 PERCENT IN THE CAPE FEAR
REGION...WITH POPS ELSEWHERE IN THE 10-30 PERCENT RANGE GIVEN
PROBABLE SUBSIDENCE AND MID-LEVEL DRYING BEHIND THE UPPER
DISTURBANCE. CONVECTION SHOULD TEND TO MOVE NORTHEASTWARD DURING THE
MID TO LATE AFTERNOON...FOLLOWING THE DISTURBANCE INTO FAR-EASTERN
NORTH CAROLINA.
TONIGHT ANOTHER UPPER DISTURBANCE TAKING A MORE INLAND TRACK COULD
SPREAD EVENING SHOWERS AND STORMS ACROSS THE I-95 CORRIDOR. I HAVE
NOT GONE TOO HIGH WITH POPS HOWEVER GIVEN THE COOLING/STABILIZING
BOUNDARY LAYER AND THE BEST LIFT WITH THE DISTURBANCE EXPECTED TO
PASS ACROSS CENTRAL AND WESTERN NORTH CAROLINA. AS LOW LEVEL WINDS
TURN SOUTHWESTERLY A MODEST LOW LEVEL JET SHOULD DEVELOP WITH 975 MB
(1000 FOOT AGL) WINDS INCREASING TO 20-25 KT. THIS SHOULD HELP KEEP
A STRONG NOCTURNAL INVERSION FROM DEVELOPING AND LOWS SHOULD ONLY
FALL TO 72-75 INLAND AND 75-78 AT THE COAST...ABOUT 7 DEGREES ABOVE
NORMAL FOR THE DATE.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY... PREFRONTAL TROUGH MOVES INTO THE CAROLINAS
AND STALLS ON THURSDAY. AHEAD OF THIS FEATURE THERE SHOULD BE AMPLE
MOISTURE FOR AT LEAST SCATTERED CONVECTIVE COVERAGE. MID LEVEL
FORCING IN THE FORM OF VORT MAXES COME LATE IN THE DAY AND AT NIGHT
PREVENTING THE NORMAL DIURNAL DYING OFF OF RADAR COVERAGE EVEN
THOUGH DEEP CONVECTION MAY BE HARDER TO COME BY DUE TO THE DECREASE
IN INSTABILITY. THIS BOUNDARY WEAKENS AND MOVES OFFSHORE BY FRIDAY
AND WAS PREVIOUSLY TO BE REPLACED BY A LEGITIMATE COLD FRONT. THIS
FRONT NOW APPEARS SLOWER LEAVING NOT MUCH IN THE WAY OF SURFACE
FEATURES IN PLACE LOCALLY. FURTHER COMPLICATING FRIDAY FORECAST IS
THE DIFFERENCE IN TIMING AMONGST MODELS WITH RESPECT TO SOME MID
LEVEL IMPULSES. IN THE END DID NOT MAKE MUCH CHANGE AND WILL ONCE
AGAIN CARRY CHANCE POPS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY... IMPRESSIVELY DEEP UPPER TROUGH DRIVES COLD
FRONT INTO THE COASTAL PLAIN ON SATURDAY. BEING ALIGNED WITH THE FLOW
ALOFT IT WILL STALL ON SUNDAY. SATURDAY OFFERS THE DEEPEST MOISTURE
AND WILL LIKELY PAN OUT BEING A VERY UNSETTLED DAY WITH PERHAPS
NUMEROUS SHOWERS AND IF THE DIURNAL TIMING IS RIGHT STRONGER
THUNDERSTORMS. MODELS AT SOME ODDS REGARDING THE DEPTH AND TILT OF
THE UPPER WAVE AND UNTIL IT ENTERS THE UPPER AIR NETWORK ITS HARD TO
SPECULATE WHICH IS CORRECT. ON SUNDAY THE DEEP MOISTURE GETS SHUNTED
OFFSHORE BUT SOME LOW LEVEL MOISTURE ALONG THE BOUNDARY WILL STILL
CALL FOR SOME LOW RAIN CHANCES MAINLY ALONG THE COAST. COOLER AND
DRYER AIR NOW APPEARS TO ARRIVE FASTER AND SHOULD BE ADVECTING IN
MODERATELY STRONGLY BY MONDAY. COOLER WEATHER WILL LAST INTO TUESDAY
AS THE CENTER OF THE LARGE HIGH BUILDS TO OUR NORTH.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 06Z...LOW STRATUS AND FOG IS MOST LIKELY TO OCCUR AT THE
INLAND AIRPORTS: FLO AND LBT. THE LATEST HRRR MODEL (WHICH HAS
DONE VERY WELL THE PAST SEVERAL NIGHTS) SHOWS LOW CEILINGS
INTERMITTENTLY PRESENT AT THESE SITES BETWEEN 08-12Z. CLOSER TO
THE COAST THE AIRMASS SHOULD SUPPORT THE DEVELOPMENT OF LOW
MARITIME CUMULUS IN A MOIST ONSHORE FLOW BEGINNING 08-09Z...WITH
TEMPORARY MVFR CEILINGS POSSIBLE. UPSTREAM SHOWERS IN THE
CHARLESTON SC VICINITY MAY PASS NEAR THE COASTAL AIRPORTS AFTER
09Z.
FOR DAYTIME WED...LOOKING AT MVFR POSSIBLE BRIEF IFR CONDITIONS FROM
CONVECTION. THIS CONVECTION MAY DEVELOP ALONG A WEAK SFC TROF
LIFTING NORTH ACROSS THE REGION...AND/OR ALONG THE LATE MORNING THRU
EARLY EVENING INLAND PROGRESSING SEA BREEZE. FOR NOW...HAVE
INDICATED VCTS AND WILL LET FOLLOWING SHIFTS UPDATE TO PINPOINT A
MORE CONCRETE TIME FOR POSSIBLE MVFR/IFR CONVECTIVE CONDITIONS. BY
THE MID TO LATE EVENING HRS...DIURNALLY DRIVEN CONVECTION SHOULD
DISSIPATE. FORCING FOR CONVECTION FROM THE MESOSCALE INDUCED SEA
BREEZE WILL DISSIPATE...AND THE SFC TROF SHOULD HAVE LIFTED NORTH OF
THE FA.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM WEDNESDAY...HIGH PRESSURE NORTH OF BERMUDA WILL BE OUR
CONTROLLING WEATHER SYSTEM THROUGH TONIGHT. TODAY`S SOUTH WINDS WILL
VEER MORE SOUTHWESTERLY TONIGHT AS A COLD FRONT...CURRENTLY MOVING
SE ACROSS ILLINOIS AND WISCONSIN...MOVES INTO WEST VIRGINIA AND
KENTUCKY. AN UPPER LEVEL DISTURBANCE CURRENTLY MOVING NORTHEASTWARD
ACROSS SOUTHERNMOST SOUTH CAROLINA MAY SPREAD ISOLATED SHOWERS ALONG
THE NORTHEASTERN SOUTH CAROLINA COAST THIS MORNING...BUT LATEST HIGH-
RES MODELS INDICATE COVERAGE OF STORMS WILL EXPAND ONCE THE
DISTURBANCE REACHES SOUTHEASTERN NORTH CAROLINA LATE THIS MORNING
AND EARLY THIS AFTERNOON. STEERING WINDS IN THE ATMOSPHERE WILL TEND
TO PUSH STORMS NORTHEASTWARD AT 10 MPH...HOWEVER ASSUMING ENOUGH
STORMS FORM COLLIDING OUTFLOW BOUNDARIES WILL ULTIMATELY DETERMINE
WHERE STORMS MOVE. MARINERS IN THE CAPE FEAR AREA WILL WANT TO KEEP
AN EYE ON THE SKY LATE THIS MORNING AND EARLY THIS AFTERNOON.
SEAS CURRENTLY AROUND 2 FEET WILL BUILD CLOSER TO 3 FEET LATE THIS
AFTERNOON AS WIND SPEEDS INCREASE WITH THE SEABREEZE. SW WINDS
WILL INCREASE TO NEAR 15 KT TONIGHT.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY... A PREFRONTAL TROUGH WILL BOOST WIND AND SEAS
ON THURSDAY. WE ARE NOT ANTICIPATING HEADLINES OR ADVISORIES, BUT
ITS BEEN FAIRLY QUIET SO THURSDAY WILL BE MORE UNSETTLED THAN THE
PAST FEW DAYS WITH THE ADVENT OF SOME 4 FT SEAS. ON FRIDAY THIS
BOUNDARY MOVES OFFSHORE AND WEAKENS IF NOT DISSIPATE ALTOGETHER. THE
20KT GUSTINESS SHOULD DROP OUT OF THE FORECAST AS WILL ANY 4 FT
WAVES. A COLD FRONT WILL ALSO BE APPROACHING FROM THE NW ON FRIDAY
BUT IT NOW LOOKS SLOWER THAN PREVIOUSLY FORECAST.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3 AM WEDNESDAY... WITH THE SLOWER ARRIVAL OF COLD FRONT ON
SATURDAY THE AREA MAY STAY IN AN INCREASED GRADIENT PRE-FRONTAL FLOW
REGIME. AS SUCH WIND SPEEDS MAY NEED TO BE RE-EVALUATED AND RAISED
ESPECIALLY AS SOME HIGHER MID LEVEL WINDS MAY BE IMPINGING UPON THE
AREA. THE UPPER WAVE DRIVING THIS SYSTEM IS FAR FROM BEING SAMPLED
BY THE UPPER AIR NETWORK HOWEVER AND SO NO LARGE CHANGES WILL BE
MADE AT THIS TIME. SHOULD THINGS KEEP SLOWING DOWN THEN A SW WIND
WILL REMAIN ON SUNDAY AS THE BOUNDARY EITHER STALLS ALONG THE COAST
OR PERHAPS JUST INLAND. EITHER WAY THE STRONGER GRADIENT WILL HAVE
PUSHED FURTHER OFFSHORE AND THE POSSIBILITY OF HIGHER WINDS AND SEAS
THAN THE CURRENT FORECAST ALONG WITH IT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MBB
NEAR TERM...TRA
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...DCH
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
315 AM EDT WED SEP 9 2015
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE OFFSHORE THROUGH FRIDAY AS WEAK LOW
PRESSURE DEVELOPS TO THE WEST. LOW PRESSURE WILL PASS NORTH OF THE
REGION SUNDAY PUSHING A COLD FRONT THROUGH THE AREA SUNDAY NIGHT.
HIGH PRESSURE WILL BUILD IN FROM THE WEST EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 225 AM WED...UPR RDG TO THE S WILL CONT TO EXTEND N INTO
THE REGION TODAY. WITH SFC HIGH OFFSHORE EXPECT S/SW LOW LVL FLOW
WITH MOISTURE REMAINING QUITE HIGH...PWAT NEAR 2 INCHES. AS INSTAB
DEVELOPS TODAY EXPECT SCT CONVECTION TO FORM ALONG SEA BRZ AND
SHIFT INLAND WITH CHC POPS INLAND TO SLIGHT CHC CST. WITH DECENT
AMOUNT OF SUN WILL SEE HIGHS NEAR 90 INLAND WITH MID/UPR 80S CST.
&&
.SHORT TERM /TONIGHT/...
AS OF 225 AM WED...SW FLOW ALOFT WILL INCREASE AS UPR TRF BEGINS
TO APPROACH FROM THE W. MAY SEE JUST ENOUGH FORCING FROM THIS
APPROACHING TRF TO KEEP ISOLD CONVECTION GOING OVERNIGHT...WITH
BEST CVRG INLAND EARLY SHIFTING TOWARD CST LATE. WILL BE A VERY
WARM NIGHT WITH SW LOW LVL FLOW...LOWS 70 TO 75 INLAND AND MID/UPR
70S BEACHES.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY...SUMMERLIKE PATTERN THROUGH THE FIRST PART
OF THE LONG TERM PERIOD WITH SCATTERED SHOWERS AND THUNDERSTORMS,
THEN A BETTER CHANCE OF PRECIP LATE IN THE WEEK, FOLLOWED BY A
STRONG COLD FRONTAL PASSAGE AND COOLER/DRIER CONDITIONS BY EARLY
NEXT WEEK.
THURSDAY THROUGH FRIDAY...LARGE SCALE TROUGH ACROSS THE NORTHERN
TIER OF THE CONUS WILL MIGRATE EASTWARD DURING THE PERIOD, WHILE
UPPER RIDGE AMPLIFIES ACROSS THE INTERMOUNTAIN WEST. THIS WILL
INDUCE STRONG DIGGING SHORTWAVE TROUGH ACROSS THE EASTERN US/OHIO
VALLEY BY THE WEEKEND. AHEAD OF THIS SYSTEM IN RESPONSE, DEEP
LAYER SOUTHWESTERLY FLOW WILL INDUCE VERY WARM AND HUMID
CONDITIONS ACROSS EASTERN NC. WEAK SURFACE FRONT WILL SLOWLY MOVE
THROUGH THE GREAT LAKES AREA, SOUTHEAST INTO THE WESTERN SLOPES OF
THE APPALACHIAN MOUNTAINS ON THURSDAY. SLIGHTLY BETTER CHANCES FOR
ORGANIZED PRECIP AS MOISTURE CONVERGENCE INCREASES OVER THE
SOUTHEAST CONUS WITH NEARLY UNIDIRECTIONAL SW FLOW OVER EASTERN
NC. MAINTAINED HIGH CHANCE POPS THURSDAY THROUGH FRIDAY FOR INLAND
ZONES DUE TO HIGH PWATS AND SHORTWAVE ENERGY ROTATING AROUND
STRONGER SHORTWAVE TO THE NORTHWEST. BULK OF UPPER LEVEL SUPPORT
WILL REMAIN NORTH OF THE REGION SO SEVERE THREAT WILL BE MINIMAL.
CONDITIONS WILL CONTINUE TO BE VERY MUGGY AND ABOVE CLIMO WITH
HIGHS 85-90 AND LOWS IN THE 70S.
THIS WEEKEND...MULTI-MODEL GUIDANCE HAS SHIFTED INTO BETTER
AGREEMENT REGARDING TO EVOLUTION OF THE DIGGING STRONG SHORTWAVE
THIS WEEKEND. 00Z GFS/GEM NOW VERY SIMILAR TO 00Z/PREVIOUS RUNS OF
THE ECMWF, THEREFORE WILL CONTINUE MUCH OF THE PREVIOUS FORECAST
THOUGH WITH GREATER CONFIDENCE IN EXPECTED SENSIBLE WX THIS
WEEKEND. THE REGION WILL REMAIN IN THE WARM SECTOR WITH GOOD
CHANCES OF SHOWERS AND STORMS ON SATURDAY. LATEST OPERATIONAL RUNS
INDICATE A STRONG SHORTWAVE MAY ALSO CROSS THE REGION SATURDAY
AFTERNOON, COINCIDENT WITH PEAK HEATING, THOUGH CLOUDS/PRECIP MAY
INHIBIT MAXIMUM INSOLATION THEREBY LIMITING INSTABILITY SOMEWHAT.
INCREASED POPS TO LIKELY FOR INLAND SECTIONS SATURDAY, TRANSLATING
TO LIKELIES ALONG THE COAST SATURDAY NIGHT AS BEST CONVERGENCE AND
MOISTURE SHIFTS OFFSHORE. INCREASING MID AND UPPER SW FLOW, ALONG
WITH SHORTWAVE IN MEAN SW FLOW, COULD BRING A THREAT FOR SEVERE
THUNDERSTORMS AS DEEP LAYER SHEAR INCREASES. THE LIMITING FACTOR
FOR SEVERE THREAT WILL BE AMOUNT OF INSTABILITY. FOR SUNDAY, MORE
QUESTIONABLE ON HOW QUICKLY SYSTEM EXITS THE EASTERN CONUS WITH A
FASTER FRONTAL PASSAGE SOLUTION BRINGING DRIER AND COOLER
CONDITIONS AND A SLOWER SCENARIO KEEPING SHOWER CHANCES THROUGH
THE DAY. TRENDED POPS LOWER SUNDAY NIGHT INTO EARLY MONDAY FROM
WEST TO EAST AS GUIDANCE HAS MOVED INTO BETTER AGREEMENT.
MONDAY AND TUESDAY...HIGH PRESSURE WILL BUILD SOUTHEAST ACROSS THE
REGION MONDAY AND TUESDAY. MONDAY SHOULD BRING A RETURN TO COOLER
AND MUCH DRIER CONDITIONS WITH HIGHS IN THE 80-85 RANGE AND LOWS
60-65 INLAND TO 65-70 BEACHES. DEWPOINTS WILL BE DOWN INTO THE 50S
BRINGING FIRST EARLY TOUCH OF FALL TO THE REGION UNDER MOSTLY
SUNNY SKIES.
&&
.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
SHORT TERM /THROUGH TONIGHT/...
AS OF 225 AM WED...MCLR SKIES...LIGHT WINDS AND HIGH LOW LVL
MOISTURE ALL WOULD SEEM FAVORABLE FOR SOME FOG/ST TO DEVELOP THRU
DAYBREAK. HIGH RES NARRE AND HRRR SHOW LITTLE TO NO IFR OVERNIGHT
SO NOT REAL CONFIDENT HOW MUCH WILL FORM WITH LIGHT SSW LOW LVL
FLOW. FOR NOW WILL SHOW PERIOD OF MAINLY IFR LATE. WHATEVER FOG OR
ST DEVELOPS SHLD LIFT FAIRLY QUICKLY IN THE MORN WITH RETURN TO
VFR. SCT SHRA/TSRA WILL DEVELOP TODAY WITH HEATING...VERY BRIEF
REDUCTIONS IN CIGS/VSBYS POSS. ISOLD CONVECTION COULD CONT
TONIGHT HOWEVER GIVEN UNCERTAIN CVRG WILL NOT MENTION IN TAFS.
SLIGHTLY STRONGER SW LOW LVL FLOW AND DECENT AMOUNT OF CLOUDS SHLD
LIMIT THREAT FOR LATE NIGHT FOG/ST.
LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 310 AM WEDNESDAY...GENERALLY VFR THROUGH THE PERIOD, THOUGH
OCCASIONAL FOG POSSIBLE EACH NIGHT/EARLY MORNING DUE TO LIGHT WINDS
AND HIGH BOUNDARY LAYER MOISTURE. TEMPO RESTRICTIONS POSSIBLE EACH
AFTERNOON DUE TO SCATTERED SHOWERS/THUNDERSTORMS. BETTER CHANCE
FOR MORE WIDESPREAD SHOWERS/THUNDERSTORMS LATE WEEK INTO FIRST
PART OF THE WEEKEND AHEAD OF A STRONG COLD FRONT. THE FRONT WILL
CROSS EASTERN NC LATE SUNDAY INTO SUNDAY NIGHT.
&&
.MARINE...
SHORT TERM /THROUGH TONIGHT/...
AS OF 225 AM WED...HIGH PRES OFFSHORE AND DEVELOPING TRF TO THE
W WILL LEAD TO MAINLY SW FLOW THRU THE PERIOD. GRDNT REMAINS
FAIRLY LOOSE TODAY WITH SPEEDS MAINLY 8 TO 12 KTS. SPEEDS WILL
INCREASE A BIT TONIGHT TO 10 TO 15 KTS. SEAS OF 2 TO 3 FEET TODAY
WILL BUILD A BIT WITH 3 TO 4 FEET OUTER WATERS LATER TONIGHT.
LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 315 AM WEDNESDAY...A TIGHTENING SOUTHWESTERLY PRESSURE
GRADIENT WILL CREATE POOR BOATING CONDITIONS THURSDAY THROUGH THE
WEEKEND.
WINDS WILL BE SW 5-15 KT THROUGH EARLY THURSDAY, THEN INCREASE TO
10-20 KT LATER THURSDAY, HIGHEST ON THE OUTER PORTIONS OF THE
COASTAL WATERS. SEAS WILL GENERALLY BE 3 FEET OR LESS THROUGH
EARLY THURSDAY, THEN BUILD 3-5 FT THURSDAY INTO FRIDAY IN RESPONSE
TO STRENGTHENING SOUTHWESTERLY WINDS. STRONG COLD FRONT WILL
APPROACH BY LATE WEEKEND AND CROSS THE EASTERN NC WATERS LATE
SUNDAY NIGHT INTO MONDAY. FORECAST CONFIDENCE HAS INCREASED WITH
REGARDS TO WEEKEND SCENARIO DUE TO MUCH BETTER AGREEMENT AMONGST
MEDIUM/LONG RANGE GUIDANCE. CONDITIONS COULD REACH MARGINAL SCA
CRITERIA WITH WIND GUSTS TO 25 KT AND 6 FT SEAS LATE SATURDAY
INTO EARLY SUNDAY AHEAD OF THE STRONG COLD FRONT. WAVEWATCH AND
LOCAL SWAN/NWPS IN GOOD AGREEMENT THROUGH THE MEDIUM RANGE, THEN
WAVEWATCH APPEARED REASONABLE FOR THE EXTENDED SEAS AS ITS GFS-
BASED WINDS ARE BETTER IN LINE WITH FORECAST WINDS.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...RF
NEAR TERM...RF
SHORT TERM...RF
LONG TERM...DAG/TL
AVIATION...RF/DAG
MARINE...RF/DAG
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
236 AM EDT WED SEP 9 2015
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE OFFSHORE THROUGH FRIDAY AS WEAK LOW
PRESSURE DEVELOPS TO THE WEST. LOW PRESSURE WILL PASS NORTH OF THE
REGION SUNDAY PUSHING A COLD FRONT THROUGH THE AREA SUNDAY NIGHT.
HIGH PRESSURE WILL BUILD IN FROM THE WEST EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 225 AM WED...UPR RDG TO THE S WILL CONT TO EXTEND N INTO THE
REGION TODAY. WITH SFC HIGH OFFSHORE EXPECT S/SW LOW LVL FLOW
WITH MOISTURE REMAINING QUITE HIGH...PWAT NEAR 2 INCHES. AS
INSTAB DEVELOPS TODAY EXPECT SCT CONVECTION TO FORM ALONG SEA BRZ
AND SHIFT INLAND WITH CHC POPS INLAND TO SLIGHT CHC CST. WITH
DECENT AMOUNT OF SUN WILL SEE HIGHS NEAR 90 INLAND WITH MID/UPR
80S CST.
&&
.SHORT TERM /TONIGHT/...
AS OF 225 AM WED...SW FLOW ALOFT WILL INCREASE AS UPR TRF BEGINS
TO APPROACH FROM THE W. MAY SEE JUST ENOUGH FORCING FROM THIS
APPROACHING TRF TO KEEP ISOLD CONVECTION GOING OVERNIGHT...WITH
BEST CVRG INLAND EARLY SHIFTING TOWARD CST LATE. WILL BE A VERY
WARM NIGHT WITH SW LOW LVL FLOW...LOWS 70 TO 75 INLAND AND
MID/UPR 70S BEACHES.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS OF 315 PM TUESDAY...SUMMERLIKE PATTERN THROUGH THE FIRST PART
OF THE LONG TERM PERIOD WITH SCATTERED SHOWERS AND THUNDERSTORMS,
THEN A BETTER CHANCE OF PRECIP LATE IN THE WEEK, FOLLOWED BY A
POSSIBLE STRONG COLD FRONTAL PASSAGE AND COOLER/DRIER CONDITIONS
BY LATE WEEKEND/EARLY NEXT WEEK.
THURSDAY THROUGH FRIDAY...LARGE SCALE TROUGH ACROSS THE NORTHERN
TIER OF THE CONUS WILL MIGRATE EASTWARD DURING THE PERIOD, WHILE
UPR RIDGE AMPLIFIES ACROSS THE INTERMOUNTAIN WEST. THIS WILL
INDUCE STRONG DIGGING SHORTWAVE TROUGH ACROSS THE EASTERN US/OHIO
VALLEY BY THE WEEKEND. AHEAD OF THIS SYSTEM IN RESPONSE...DEEP
LAYER SWRLY FLOW WILL PUMP IN VERY WARM AND HUMID CONDITIONS. WEAK
SURFACE FRONT WILL SLOWLY MOVE THROUGH THE GREAT LAKES AREA,
SOUTHEAST INTO THE WESTERN SLOPES OF THE APPALACHIAN MOUNTAINS ON
THURSDAY. SLIGHTLY BETTER CHANCES FOR ORGANIZED PRECIP AS
MOISTURE CONVERGENCE INCREASES OVER THE SOUTHEAST CONUS WITH
NEARLY UNIDIRECTIONAL SW FLOW OVER EASTERN NC. MAINTAINED HIGH
CHANCE POPS THURSDAY THROUGH FRIDAY FOR INLAND ZONES DUE TO HIGH
PWATS AND PIECES OF SHORTWAVE ENERGY ROTATING AROUND STRONGER
SHORTWAVE TO THE NORTH AND WEST. THE BULK OF UPPER LEVEL SUPPORT
WILL REMAIN NORTH OF THE REGION SO SEVERE THREAT WILL BE MINIMAL.
CONDITIONS WILL CONTINUE TO BE VERY MUGGY AND ABOVE CLIMO WITH
HIGHS 85-90 AND LOWS IN THE 70S.
THIS WEEKEND...THERE ARE STILL SOME DIFFERENCES AMONGST MODEL
SUITE IN REGARDS TO EVOLUTION OF THE DIGGING STRONG SHORTWAVE
THIS WEEKEND. HAVE CONTINUED TO FOLLOW MORE CLOSELY TO WPC/ECMWF
SOLN. A LOOK AT THE ENSEMBLE MEAN HEIGHTS INDICATE THE NCEP/ECM
ENSEMBLE MEAN ALONG WITH ECMWF/GEM GLOBAL HAVE FAIRLY UNANIMOUS
SUPPORT WITH HANDLING UP UPR LOW/SHORTWAVE POSITIONING ACROSS THE
OHIO VALLEY...WHILE DETERMINISTIC GFS STILL A BIT OF AN OUTLIER. THIS
WILL KEEP AREA IN THE WARM SECTOR WITH GOOD CHANCES OF SHOWERS AND
STORMS ON SATURDAY. WILL RAISE POPS A BIT...INTO THE 40-50 PERCENT
RANGE. INCREASING MID AND UPPER SW FLOW COULD BRING A THREAT FOR
SEVERE STORMS AS DEEP LAYER SHEAR INCREASES...WITH SEVERE THREAT
BEING DEPENDENT ON AMOUNT OF AVAILABLE INSTABILITY. FOR SUNDAY,
MORE QUESTIONABLE ON HOW QUICKLY SYSTEM EXITS THE EASTERN CONUS
WITH A FASTER FRONTAL PASSAGE SOLUTION BRINGING DRIER AND COOLER
CONDITIONS AND A SLOWER SCENARIO KEEPING SHOWER CHANCES THROUGH
THE DAY. FOR NOW WILL MAINTAIN THE 30 POPS.
MONDAY AND TUESDAY...MONDAY SHOULD BRING A RETURN TO COOLER AND
MUCH DRIER CONDITIONS WITH HIGHS IN THE 80-85 RANGE AND LOWS 60-65
INLAND TO 65-70 BEACHES. TD`S WILL BE DOWN INTO THE 50S BRINGING
FIRST EARLY TOUCH OF FALL TO THE REGION UNDER MOSTLY SUNNY SKIES.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
SHORT TERM /THROUGH TONIGHT/...
AS OF 225 AM WED...MCLR SKIES...LIGHT WINDS AND HIGH LOW LVL
MOISTURE ALL WOULD SEEM FAVORABLE FOR SOME FOG/ST TO DEVELOP THRU
DAYBREAK. HIGH RES NARRE AND HRRR SHOW LITTLE TO NO IFR OVERNIGHT
SO NOT REAL CONFIDENT HOW MUCH WILL FORM WITH LIGHT SSW LOW LVL
FLOW. FOR NOW WILL SHOW PERIOD OF MAINLY IFR LATE. WHATEVER FOG OR
ST DEVELOPS SHLD LIFT FAIRLY QUICKLY IN THE MORN WITH RETURN TO
VFR. SCT SHRA/TSRA WILL DEVELOP TODAY WITH HEATING...VERY BRIEF
REDUCTIONS IN CIGS/VSBYS POSS. ISOLD CONVECTION COULD CONT
TONIGHT HOWEVER GIVEN UNCERTAIN CVRG WILL NOT MENTION IN TAFS.
SLIGHTLY STRONGER SW LOW LVL FLOW AND DECENT AMOUNT OF CLOUDS SHLD
LIMIT THREAT FOR LATE NIGHT FOG/ST.
LONG TERM /THU THROUGH SUNDAY/...
AS OF 315 PM TUESDAY...GENERALLY VFR THROUGH THE PERIOD, THOUGH
OCCASIONAL FOG POSSIBLE EACH NIGHT/EARLY MORNING DUE TO CALM WINDS
AND HIGH BOUNDARY LAYER MOISTURE. TEMPO RESTRICTIONS POSSIBLE EACH
AFTERNOON DUE TO SCATTERED SHOWERS/THUNDERSTORMS. BETTER CHANCE
FOR MORE WIDESPREAD SHOWERS/THUNDERSTORMS LATE WEEK INTO FIRST
PART OF THE WEEKEND AHEAD OF A STRONG COLD FRONT. WINDS WILL INC
OUT OF THE SW ON THUR AND BECOME GUSTY 12-16 KT.
&&
.MARINE...
SHORT TERM /THROUGH TONIGHT/...
AS OF 225 AM WED...HIGH PRES OFFSHORE AND DEVELOPING TRF TO THE
W WILL LEAD TO MAINLY SW FLOW THRU THE PERIOD. GRDNT REMAINS
FAIRLY LOOSE TODAY WITH SPEEDS MAINLY 8 TO 12 KTS. SPEEDS WILL
INCREASE A BIT TONIGHT TO 10 TO 15 KTS. SEAS OF 2 TO 3 FEET TODAY
WILL BUILD A BIT WITH 3 TO 4 FEET OUTER WTRS LATER TONIGHT.
LONG TERM /THU THROUGH SUNDAY/...
AS OF 315 PM TUESDAY...A TIGHTENING SOUTHWESTERLY PRESSURE
GRADIENT WILL CREATE MARGINAL CONDITIONS BY THURSDAY THROUGH THE
WEEKEND.
WINDS WILL BE SW 5-15 KT THROUGH EARLY THURSDAY, THEN INCREASE TO
10-20 KT LATER THURSDAY, HIGHEST ON THE OUTER PORTIONS OF THE
COASTAL WATERS. SEAS WILL GENERALLY BE 3 FEET OR LESS THROUGH
EARLY THURSDAY, THEN BUILD 3-5 FT THURSDAY INTO FRIDAY IN RESPONSE
TO STRENGTHENING SOUTHWESTERLY WINDS. STRONG COLD FRONT WILL
APPROACH BY LATE WEEKEND, THOUGH FORECAST CONFIDENCE STILL
RELATIVELY LOW AT THIS TIME DUE TO DISAGREEMENT AMONGST GUIDANCE
IN THE FAR EXTENDED PERIOD. CONTINUED AROUND A FOOT HIGHER THAN
12Z WAVEWATCH GUIDANCE AS ITS GFS-BASED WINDS WERE LOWER THAN FCST
15-20 KT SUSTAINED WINDS. CONDITIONS COULD REACH MARGINAL SCA
CRITERIA WITH 6 FOOT SEAS FOR A TIME LATE SATURDAY INTO EARLY
SUNDAY AHEAD OF THE STRONG COLD FRONT.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...RF
NEAR TERM...RF
SHORT TERM...RF
LONG TERM...TL/DAG
AVIATION...RF/TL
MARINE...RF/TL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
150 AM EDT WED SEP 9 2015
.SYNOPSIS...
SUMMERTIME HEAT AND HUMIDITY WILL RETURN AS HIGH PRESSURE
CONTINUES OVER THE REGION THROUGH THURSDAY. A COLD FRONT WILL
APPROACH FROM THE WEST THURSDAY AFTERNOON AND THEN STALL ALONG THE
COAST WHICH WILL INCREASE THE RISK FOR THUNDERSTORMS INTO THE
WEEKEND. THE FRONT WILL SLOWLY DISSIPATE EARLY NEXT WEEK AS HIGH
PRESSURE RETURNS.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 100 AM WEDNESDAY...SHOWERS ARE DEVELOPING UPSTREAM IN THE
CHARLESTON VICINITY MUCH LIKE THE 02Z HRRR INDICATES. ADVECTION OF
THIS CONVECTION ACROSS THE SANTEE RIVER INTO NE SOUTH CAROLINA IS
POSSIBLE AFTER 2-3 AM. OTHERWISE SKIES ARE CURRENTLY CLEAR TO
PARTLY CLOUDY WITH PATCHY FOG ACROSS THE AREA. UPDATES WITH THIS
FINAL NEAR-TERM UPDATE OF THE NIGHT INCLUDE TWEAKS TO
SKY...WIND...AND DEWPOINT. DISCUSSION FROM 1000 PM FOLLOWS...
THE HIGH RESOLUTION MODELS CONTINUE TO SHOW SOME UPTICK IN
CONVECTION AS DAYBREAK APPROACHES. WEAK LOW PRESSURE ACROSS
GEORGIA DOES LIFT N ACROSS SOUTH CAROLINA OVERNIGHT. GIVEN HOW
QUICKLY CONVECTION HAS DISSIPATED THIS EVE...WILL CONFINE
MENTIONABLE POPS TO THE CLIMATOLOGICALLY FAVORED WARM OCEAN WATERS
AND ADJACENT IMMEDIATE COAST WITH THE APPROACH OF DAYBREAK WHERE
SOME WEAK LOW-LEVEL CONVERGENCE WAS NOTED.
PROFILES DO NOT SUPPORT DENSE FOG OVERNIGHT. THE WEDGE WHICH HAD
BEEN IN PLACE LAST NIGHT...HAS BROKEN DOWN AND WARM SOUTHERLY
WINDS HAVE RETURNED. WINDS ABOVE THE BOUNDARY LAYER WILL BE IN THE
15 TO 20 KT RANGE FOR MOST OF THE OVERNIGHT. CONSIDERABLE CONVECTIVE
CLOUD DEBRIS SHOULD CONTINUE TO FILTER ACROSS THE AREA FROM THE
SOUTH. GIVEN THE LACK OF SIGNALS SUPPORTING SIGNIFICANT FOG...WILL
OPT TO LEAVE FOG OUT OF THE FORECAST.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/...
AS OF 300 PM TUESDAY...UPPER LEVEL HIGH PRESSURE CENTERED OVER THE
FLORIDA STRAITS WILL BRING IN VERY WARM 500 MB TEMPERATURES OF -
5.5C. THIS COMBINED WITH PRECIPITABLE WATER OF AROUND 2 INCHES WILL
PROVIDE ABOVE NORMAL TEMPERATURES AND SCATTERED DIURNAL CONVECTION
FOR WEDNESDAY. HIGHS ARE EXPECTED TO REACH INTO THE LOWER 90S INLAND
AND NEAR NINETY AT THE BEACHES.
ALOFT THE SOUTHERLY FLOW WILL SLOWLY VEER TO THE SOUTHWEST AHEAD OF
COLD FRONT THAT WILL APPROACH THE REGION ON THURSDAY BEFORE STALLING
INTO THE AREA OVERNIGHT. LITTLE TO NO STRONG SYNOPTIC FORCING BOTH
WEDNESDAY AND THURSDAY SO MESOSCALE LIFT WILL BE THE MAIN TRIGGER
FOR THE SCATTERED LOCATION EACH DAY. WITH THE FRONTAL BOUNDARY STILL
LINGERING TO THE WEST ON THURSDAY HIGHS ARE EXPECTED TO THE LOWER
90S MOST LOCALES. LOW TEMPERATURE BOTH DAYS ARE EXPECTED TO FALL
INTO THE LOWER TO MIDDLE 70S.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
AS OF 300 PM TUESDAY...THE EXTENDED FORECAST WILL BE DOMINATED BY
SIGNIFICANT AMPLITUDE AT THE MID LEVELS AT LEAST THROUGH THE
WEEKEND. A POTENT TROUGH WILL DEEPEN FURTHER AND POSSIBLY EVEN
CUTOFF AS ADVERTISED BY SOME GUIDANCE BUT CERTAINLY DEEPEN THROUGH
SUNDAY BEFORE FINALLY GETTING KICKED BY AN UPSTREAM SYSTEM OPENING
UP AND MOVING OFF IN THE WESTERLIES. AT THE SURFACE A FRONT WILL
BE ESSENTIALLY STATIONARY OVER THE CWA THROUGH MONDAY MORNING
FINALLY PUSHING THROUGH AS THE TROUGH LIFTS OUT. WITH THE TROUGH
IN THE MIDWEST...THE EASTERN CAROLINAS WILL BE UNDER A DEEP AND
MOIST SOUTHWEST FLOW THUS SHOWERS AND THUNDERSTORMS ARE FAIR GAME
JUST ABOUT ANYTIME. IT APPEARS THE BEST SHOT AT LEAST WITH THE
LATEST GUIDANCE APPEARS TO BE SATURDAY INTO EARLY SUNDAY WHEN THE
MOISTURE AND LOW LEVEL FORCING TEAM UP WITH A DECENT 300MB JET.
TEMPERATURE FORECAST REMAINS BASICALLY UNCHANGED WITH LOW DIURNAL
RANGES EARLY WITH A COOL DOWN AND HIGHER SPREAD MONDAY AND
TUESDAY.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 06Z...LOW STRATUS AND FOG IS MOST LIKELY TO OCCUR AT THE
INLAND AIRPORTS: FLO AND LBT. THE LATEST HRRR MODEL (WHICH HAS
DONE VERY WELL THE PAST SEVERAL NIGHTS) SHOWS LOW CEILINGS
INTERMITTENTLY PRESENT AT THESE SITES BETWEEN 08-12Z. CLOSER TO
THE COAST THE AIRMASS SHOULD SUPPORT THE DEVELOPMENT OF LOW
MARITIME CUMULUS IN A MOIST ONSHORE FLOW BEGINNING 08-09Z...WITH
TEMPORARY MVFR CEILINGS POSSIBLE. UPSTREAM SHOWERS IN THE
CHARLESTON SC VICINITY MAY PASS NEAR THE COASTAL AIRPORTS AFTER
09Z.
FOR DAYTIME WED...LOOKING AT MVFR POSSIBLE BRIEF IFR CONDITIONS FROM
CONVECTION. THIS CONVECTION MAY DEVELOP ALONG A WEAK SFC TROF
LIFTING NORTH ACROSS THE REGION...AND/OR ALONG THE LATE MORNING THRU
EARLY EVENING INLAND PROGRESSING SEA BREEZE. FOR NOW...HAVE
INDICATED VCTS AND WILL LET FOLLOWING SHIFTS UPDATE TO PINPOINT A
MORE CONCRETE TIME FOR POSSIBLE MVFR/IFR CONVECTIVE CONDITIONS. BY
THE MID TO LATE EVENING HRS...DIURNALLY DRIVEN CONVECTION SHOULD
DISSIPATE. FORCING FOR CONVECTION FROM THE MESOSCALE INDUCED SEA
BREEZE WILL DISSIPATE...AND THE SFC TROF SHOULD HAVE LIFTED NORTH OF
THE FA.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 100 AM WEDNESDAY...CURRENTLY OBSERVATIONS INDICATE WINDS
LESS THAN 10 KNOTS EXCEPT RIGHT UP ON THE BEACHES WHERE SOME
RECENT GUSTS HAVE BEEN IN THE 12-14 KNOT RANGE. MINOR TWEAKS ARE
ALL THAT ARE NEEDED TO THE FORECAST. DISCUSSION FROM 1000 PM
FOLLOWS...
SOUTHERLY WINDS WILL REMAIN IN PLACE OVERNIGHT AHEAD OF AN INLAND
TROUGH. THIS SHOULD KEEP WINDS IN THE 10 TO 15 KT RANGE. SEAS OF
MAINLY 2 FT SHOULD BUILD A HALF FOOT TO A FOOT THROUGH WED
MORNING. CONVECTION IS EXPECTED TO DEVELOP ACROSS THE WATERS AND
OFFSHORE DURING THE LATE NIGHT AND MORNING HOURS OF WED.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 300 PM TUESDAY...HIGH PRESSURE DURING THE EARLY PORTION OF
THIS PERIOD WILL SLOWLY WEAKEN AS A FRONTAL BOUNDARY MOVES INTO
THE CENTRAL PORTIONS OF THE CAROLINAS BY THURSDAY NIGHT. WINDS
WILL BECOME MORE SOUTHWESTERLY WITH TIME AND A INCREASE IN WINDS
OF 15 TO 20 KNOTS IS EXPECTED THURSDAY NIGHT. SEAS ARE EXPECTED TO
SLOWLY BUILD INTO THE 3 TO 4 FT RANGE BY FRIDAY NIGHT WITH AN
ISOLATED 5 FOOTER POSSIBLE. A SMALL CRAFT EXERCISE CAUTION IS
POSSIBLE THURSDAY NIGHT.
LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 300 PM TUESDAY...WINDS WILL BE MOSTLY FROM THE SOUTHWEST
FRIDAY AND SATURDAY AS A COLD FRONT GETS HUNG UP INLAND. WIND
SPEEDS SEEM TO BE HIGHEST FRIDAY BEFORE THE FRONT WEAKENS AND IN
THE 10-15 KNOT RANGE. SATURDAY WINDS SHOULD DIMINISH TO NEAR TEN
KNOTS. TOUGH CALL ON WINDS FOR SUNDAY AS LOW PRESSURE IS PROGGED
TO DEVELOP INLAND WHICH WILL TURN THE WINDS TO THE SOUTHEAST FOR A
WHILE. SIGNIFICANT SEAS SHOULD END UP IN A 1-3 FOOT RANGE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...RJD
NEAR TERM...RJD/TRA
SHORT TERM...DRH
LONG TERM...SHK
AVIATION...DCH/TRA
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
1230 AM EDT WED SEP 9 2015
.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFFSHORE THROUGH MIDWEEK AS WEAK LOW
PRESSURE DEVELOPS TO THE WEST. A STRONG COLD FRONT WILL APPROACH
FROM THE WEST LATE IN THE WEEK AND CROSS THE AREA BY LATE THIS
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1225 AM WED...NO SIGNIF CHANGES OVERNIGHT WITH MOST AREAS
REMAINING DRY. DID ADD SLIGHT POP TOWARD DAYBREAK NEAR S CST
WHERE MDLS SHOW SOME POSS OF SHRA/TSRA DEVELOPING.
PREV DISC...PRECIPITATION HAS DISSIPATED ACROSS OUR CWA AND HAVE
REMOVED ALL POPS FROM THE FORECAST OVERNIGHT. LATEST RUN OF THE
3KM HRRR AND RUC MODELS INDICATE NO ADDITIONAL PRECIPITATION OVER
LAND AREAS OVERNIGHT. WITH HIGH LOW- LEVEL MOISTURE AND LIGHT
WINDS...FOG IS A GOOD BET OVERNIGHT. NO CHANGES TO FORECAST
TEMPERATURES WITH LOWS AROUND 70 INLAND TO MID 70S BEACHES.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TODAY/...
AS OF 2 PM TUE...WEAK UPPER RIDGING OVER THE BAHAMAS/FLORIDA WITH
LONG WAVE TROUGHING ACROSS THE UPPER PLAINS/MIDWEST WILL RESULT IN
SOUTHWESTERLY FLOW ALOFT. S TO SW SFC SFC WINDS WILL RESULT IN
WARM AND MUGGY CONDITIONS ALONG WITH ISOLATED TO SCATTERED DIURNAL
SHOWERS AND THUNDERSTORMS...BEST CHANCES ALONG THE SEA BREEZE.
COASTAL AREAS SHOULD REMAIN MOSTLY DRY AND THE SEVERE THREAT IS
LOW DUE TO WEAK UPPER LEVEL SUPPORT. HIGHS WILL RANGE FROM NEAR 90
INLAND TO MID 80S BEACHES.
&&
.LONG TERM /TONIGHT THROUGH TUESDAY/...
AS OF 315 PM TUESDAY...SUMMERLIKE PATTERN THROUGH THE FIRST PART
OF THE LONG TERM PERIOD WITH SCATTERED SHOWERS AND THUNDERSTORMS,
THEN A BETTER CHANCE OF PRECIP LATE IN THE WEEK, FOLLOWED BY A
POSSIBLE STRONG COLD FRONTAL PASSAGE AND COOLER/DRIER CONDITIONS
BY LATE WEEKEND/EARLY NEXT WEEK.
THURSDAY THROUGH FRIDAY...LARGE SCALE TROUGH ACROSS THE NORTHERN
TIER OF THE CONUS WILL MIGRATE EASTWARD DURING THE PERIOD, WHILE
UPR RIDGE AMPLIFIES ACROSS THE INTERMOUNTAIN WEST. THIS WILL
INDUCE STRONG DIGGING SHORTWAVE TROUGH ACROSS THE EASTERN US/OHIO
VALLEY BY THE WEEKEND. AHEAD OF THIS SYSTEM IN RESPONSE...DEEP
LAYER SWRLY FLOW WILL PUMP IN VERY WARM AND HUMID CONDITIONS. WEAK
SURFACE FRONT WILL SLOWLY MOVE THROUGH THE GREAT LAKES AREA,
SOUTHEAST INTO THE WESTERN SLOPES OF THE APPALACHIAN MOUNTAINS ON
THURSDAY. SLIGHTLY BETTER CHANCES FOR ORGANIZED PRECIP AS
MOISTURE CONVERGENCE INCREASES OVER THE SOUTHEAST CONUS WITH
NEARLY UNIDIRECTIONAL SW FLOW OVER EASTERN NC. MAINTAINED HIGH
CHANCE POPS THURSDAY THROUGH FRIDAY FOR INLAND ZONES DUE TO HIGH
PWATS AND PIECES OF SHORTWAVE ENERGY ROTATING AROUND STRONGER
SHORTWAVE TO THE NORTH AND WEST. THE BULK OF UPPER LEVEL SUPPORT
WILL REMAIN NORTH OF THE REGION SO SEVERE THREAT WILL BE MINIMAL.
CONDITIONS WILL CONTINUE TO BE VERY MUGGY AND ABOVE CLIMO WITH
HIGHS 85-90 AND LOWS IN THE 70S.
THIS WEEKEND...THERE ARE STILL SOME DIFFERENCES AMONGST MODEL
SUITE IN REGARDS TO EVOLUTION OF THE DIGGING STRONG SHORTWAVE
THIS WEEKEND. HAVE CONTINUED TO FOLLOW MORE CLOSELY TO WPC/ECMWF
SOLN. A LOOK AT THE ENSEMBLE MEAN HEIGHTS INDICATE THE NCEP/ECM
ENSEMBLE MEAN ALONG WITH ECMWF/GEM GLOBAL HAVE FAIRLY UNANIMOUS
SUPPORT WITH HANDLING UP UPR LOW/SHORTWAVE POSITIONING ACROSS THE
OHIO VALLEY...WHILE DETERMINISTIC GFS STILL A BIT OF AN OUTLIER. THIS
WILL KEEP AREA IN THE WARM SECTOR WITH GOOD CHANCES OF SHOWERS AND
STORMS ON SATURDAY. WILL RAISE POPS A BIT...INTO THE 40-50 PERCENT
RANGE. INCREASING MID AND UPPER SW FLOW COULD BRING A THREAT FOR
SEVERE STORMS AS DEEP LAYER SHEAR INCREASES...WITH SEVERE THREAT
BEING DEPENDENT ON AMOUNT OF AVAILABLE INSTABILITY. FOR SUNDAY,
MORE QUESTIONABLE ON HOW QUICKLY SYSTEM EXITS THE EASTERN CONUS
WITH A FASTER FRONTAL PASSAGE SOLUTION BRINGING DRIER AND COOLER
CONDITIONS AND A SLOWER SCENARIO KEEPING SHOWER CHANCES THROUGH
THE DAY. FOR NOW WILL MAINTAIN THE 30 POPS.
MONDAY AND TUESDAY...MONDAY SHOULD BRING A RETURN TO COOLER AND
MUCH DRIER CONDITIONS WITH HIGHS IN THE 80-85 RANGE AND LOWS 60-65
INLAND TO 65-70 BEACHES. TD`S WILL BE DOWN INTO THE 50S BRINGING
FIRST EARLY TOUCH OF FALL TO THE REGION UNDER MOSTLY SUNNY SKIES.
&&
.AVIATION /04Z WEDNESDAY THROUGH SUNDAY/...
SHORT TERM /THROUGH 00Z THURSDAY/...
AS OF 1225 AM WED...MCLR SKIES...LIGHT WINDS AND HIGH LOW LVL
MOISTURE ALL WOULD SEEM FAVORABLE FOR SOME FOG/ST TO DEVELOP. HIGH
RES NARRE AND HRRR SHOW LITTLE TO NO IFR OVERNIGHT SO NOT REAL
CONFIDENT HOW MUCH WILL FORM WITH LIGHT SSW LOW LVL FLOW. FOR NOW
WILL SHOW PERIOD OF IFR INLAND AND MVFR CST LATER TONIGHT.
WHATEVER FOG OR ST DEVELOPS SHLD LIFT FAIRLY QUICKLY IN THE MORN
WITH RETURN TO VFR. SCT SHRA/TSRA WILL DEVELOP WED WITH HEATING
WITH VERY BRIEF REDUCTIONS IN CIGS/VSBYS POSS.
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/
AS OF 315 PM TUESDAY...GENERALLY VFR THROUGH THE PERIOD, THOUGH
OCCASIONAL FOG POSSIBLE EACH NIGHT/EARLY MORNING DUE TO CALM WINDS
AND HIGH BOUNDARY LAYER MOISTURE. TEMPO RESTRICTIONS POSSIBLE EACH
AFTERNOON DUE TO SCATTERED SHOWERS/THUNDERSTORMS. BETTER CHANCE
FOR MORE WIDESPREAD SHOWERS/THUNDERSTORMS LATE WEEK INTO FIRST
PART OF THE WEEKEND AHEAD OF A STRONG COLD FRONT. WINDS WILL INC
OUT OF THE SW ON THUR AND BECOME GUSTY 12-16 KT.
&&
.MARINE...
SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
AS OF 1225 AM WED...FCST LOOKS GOOD WITH NO SIGNIF CHANGES
PLANNED.
PREV DISC...MINOR ADJUSTMENTS TO WIND DIRECTION AS WINDS ARE
GENERALLY SE/S AT SPEEDS OF 10 KNOTS OR LESS WITH SEAS GENERALLY 2
TO 3 FEET WITH SOME LONGER PERIOD SWELL ENERGY. NO CHANGES TO THIS
ARE EXPECTED OVERNIGHT. WINDS VEER TO MORE SW BY EARLY WEDNESDAY
AS AXIS OF HIGH PRESSURE RIDGE SHIFTS OFFSHORE. SEAS CONTINUE AT 2
TO 3 FEET FOR WEDNESDAY.
LONG TERM /WED NIGHT THROUGH SUNDAY/
AS OF 315 PM TUESDAY...GENERALLY GOOD BOATING CONDITIONS CONTINUE
THROUGH WEDNESDAY NIGHT, THEN A TIGHTENING SOUTHWESTERLY PRESSURE
GRADIENT WILL CREATE MARGINAL CONDITIONS BY THURSDAY THROUGH THE
WEEKEND.
WINDS WILL BE SW 5-15 KT WEDNESDAY NIGHT THROUGH EARLY THURSDAY,
THEN INCREASE TO 10-20 KT LATER THURSDAY, HIGHEST ON THE OUTER
PORTIONS OF THE COASTAL WATERS. SEAS WILL GENERALLY BE 3 FEET OR
LESS THROUGH EARLY THURSDAY, THEN BUILD 3-5 FT THURSDAY INTO
FRIDAY IN RESPONSE TO STRENGTHENING SOUTHWESTERLY WINDS. STRONG
COLD FRONT WILL APPROACH BY LATE WEEKEND, THOUGH FORECAST
CONFIDENCE STILL RELATIVELY LOW AT THIS TIME DUE TO DISAGREEMENT
AMONGST GUIDANCE IN THE FAR EXTENDED PERIOD. CONTINUED AROUND A
FOOT HIGHER THAN 12Z WAVEWATCH GUIDANCE AS ITS GFS-BASED WINDS
WERE LOWER THAN FCST 15-20 KT SUSTAINED WINDS. CONDITIONS COULD
REACH MARGINAL SCA CRITERIA WITH 6 FOOT SEAS FOR A TIME LATE
SATURDAY INTO EARLY SUNDAY AHEAD OF THE STRONG COLD FRONT.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JAC
NEAR TERM...RF/CTC
SHORT TERM...JAC
LONG TERM...DAG/TL
AVIATION...RF/TL
MARINE...RF/CTC/TL
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1250 AM CDT WED SEP 9 2015
.UPDATE...
ISSUED AT 1250 AM CDT WED SEP 9 2015
COLD FRONTAL BOUNDARY WILL CONTINUE TO MOVE SLOWLY SOUTH INTO THE
NORTHERN PLAINS LATE TONIGHT THROUGH WEDNESDAY. COMBINED WITH MID
LEVEL EMBEDDED S/WV TROUGHS AND UPPER LEVEL JET DYNAMICS...CLOUD
COVER AND CHANCES FOR LIGHT SHOWERS CAN BE EXPECTED EARLY THIS
MORNING THROUGH AT LEAST WEDNESDAY NIGHT STARTING NORTH AND SLOWLY
EXPANDING SOUTHWARD ALONG THE FROPA.
HAVE A SLIGHT CHANCE OF SHOWERS NOW STARTING IN THE NORTHWEST AND
EXPANDING EAST AND SLIGHTLY SOUTH WITH TIME THROUGH THE AM HOURS.
JET ENTRANCE DYNAMICS TRIGGERING AN AREA OF LIGHT SHOWERS NOW
MOVING INTO NORTHEASTERN MONTANA. WITH CLOUD BASES AROUND 10K FT
AGL IN SOUTHERN SASKATCHEWAN...UNSURE HOW MUCH OF THE RADAR
RETURNS ARE ACTUALLY REACHING THE GROUND. WILL INCREASE POPS
ACCORDINGLY IF WE START MEASURING.
UPDATE ISSUED AT 848 PM CDT TUE SEP 8 2015
AT 830 PM CDT...A COLD FRONTAL BOUNDARY EXTENDED ACROSS SOUTHWEST
SASKATCHEWAN. THE FRONT WILL SLOWLY SLIDE SOUTHEAST TONIGHT AND
WEDNESDAY WITH ONLY A SLOW SOUTHWARD MOVING COMPONENT AS IT
NEARLY ALIGNS WITH THE FLOW ALOFT. LATEST HRRR MODEL RUNS SHOW
SOME SCATTERED SHOWERS ACROSS THE NORTHWEST AFTER 09Z TONIGHT AND
NORTH CENTRAL AFTER 12Z WEDNESDAY. ADDED MORE SLIGHT CHANCE AREA
TO THE NORTHWEST IN CONCERT WITH THE HRRR AFTER 09Z. OTHERWISE
CURRENT FORECAST LOOKS GOOD.
UPDATE ISSUED AT 553 PM CDT TUE SEP 8 2015
THE NORTHERN PLAINS REMAINS ON THE SOUTHERN EDGE OF A LARGE UPPER
LOW ACROSS NORTHERN MANITOBA. THIS HAS MAINTAINED A BREEZY
NORTHWEST FLOW ACROSS THE REGION SO FAR THIS AFTERNOON. AS THE
EVENING APPROACHES EXPECT WINDS TO DIMINISH AFTER 7 PM AND SKIES
TO BECOME MOSTLY CLEAR. UPDATED CURRENT OBSERVATIONS AND SKY
CONDITION ONLY.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 239 PM CDT TUE SEP 8 2015
QUIET WEATHER HIGHLIGHTS THE SHORT TERM FORECAST.
GIVEN GOOD AGREEMENT...UTILIZED A BLEND OF THE 12 UTC GUIDANCE
SUITES. OVERALL...WEAK HIGH PRESSURE ACROSS WESTERN AND CENTRAL
NORTH DAKOTA SOUTH OF THE FILLING NORTHERN MANITOBA LOW WILL
CONTINUE TO WEAKEN THROUGH THE NIGHT. A WEAK IMPULSE EMBEDDED IN
NORTHWEST FLOW ALOFT ON WEDNESDAY MAY SUPPORT ISOLATED RAIN SHOWER
DEVELOPMENT DURING THE AFTERNOON. GIVEN WEAK MID LEVEL LAPSE
RATES...DID NOT INCLUDE A MENTION OF THUNDER AT THIS TIME.
TEMPERATURES WEDNESDAY ARE EXPECTED TO BE SIMILAR TO TODAY WITH
60S NORTH AND 70S SOUTH.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 239 PM CDT TUE SEP 8 2015
NO MAIN CONCERNS IN THE LONG TERM WITH FAIRLY DRY AND QUIET WEATHER
EXPECTED.
EARLY IN THE LONG TERM THE NORTHWEST FLOW ALOFT WITH A FEW UPPER
LEVEL SHORTWAVES...COMBINED WITH A COLD FRONTAL BOUNDARY OVER THE
STATE WILL KEEP SMALL CHANCES OF SHOWERS IN THE FORECAST WEDNESDAY
NIGHT AND THURSDAY. FAIRLY COOL WITH LOWS IN THE UPPER 30S TO UPPER
40S...AND HIGHS MAINLY IN THE 60S.
ANOTHER COOL NIGHT THURSDAY NIGHT AS THE COOL HIGH PRESSURE CENTER
SETTLES OVER THE DAKOTAS BY FRIDAY MORNING. LOWS IN THE MID TO UPPER
30S TO LOWER 40S. THEN A WARMING TREND INTO THE WEEKEND AS THE
WESTERN RIDGE BUILDS BACK INTO THE WESTERN PLAINS.
THE NEXT CHANCE FOR WIDESPREAD SHOWERS SHOULD BE TUESDAY. THE
WESTERN RIDGE WILL BECOME MORE ZONAL OVER THE WEEKEND...THEN
SOUTHWEST FLOW ALOFT RETURNS BY TUESDAY AS AN UPPER LEVEL TROUGH
DIVES SOUTHEAST FROM THE GULF OF ALASKA INTO THE WEST
COAST...DEVELOPING A SURFACE LOW IN THE LEE OF THE ROCKIES BY
TUESDAY MORNING...BRINGING BETTER CHANCES FOR PRECIPITATION NEXT
WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1250 AM CDT WED SEP 9 2015
INCREASING MID TO UPPER LEVEL CLOUDS AS SURFACE LOW PRESSURE
ACROSS NORTHEAST MONTANA AND AN ASSOCIATED WEAK COLD FRONT
APPROACHES NORTH DAKOTA TONIGHT INTO WEDNESDAY. FOR THE 06Z TAF
VFR IS EXPECTED. AN INCREASE IN CLOUDS AOA 5 THOUSAND AGL IS
EXPECTED NORTH HALF OF THE STATE ALONG WITH VCSH FOR KISN-KMOT
THROUGH THE PERIOD.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...AYD
LONG TERM...JV
AVIATION...NH
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
343 AM EDT WED SEP 9 2015
.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE REGION TODAY THROUGH
TONIGHT...BRINGING OCCASIONAL SHOWERS AND A CHANCE OF A FEW
THUNDERSTORMS. COOLER AIR WILL SETTLE IN BEHIND THIS FRONT BY
THURSDAY. ANOTHER FRONT WILL MOVE THROUGH THE REGION ON
FRIDAY...WITH EVEN COOLER CONDITIONS EXPECTED FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS HIGH PRESSURE SOUTHEAST OF THE OHIO VALLEY LOSES ITS INFLUENCE
OVER THE REGION...A TRANSITION IN WEATHER PATTERN IS UNDERWAY.
SURFACE OBSERVATIONS AT 07Z PLACE A COLD FRONT ALONG AN AXIS FROM
BAD AXE MICHIGAN TO SPRINGFIELD ILLINOIS. WHAT THIS FRONT WILL
EVENTUALLY USHER IN OVER THE NEXT DAY OR SO IS A 10-12 DEGREE DROP
IN TEMPERATURES...ALONG WITH LESS HUMID CONDITIONS.
WHAT THE FRONT LACKS IS MUCH IN THE WAY OF FOCUS...STRENGTH...OR
SPEED. IT WILL TAKE MOST OF THE DAY FOR THE SURFACE FRONT TO CROSS
THE FORECAST AREA...WHICH WILL ALLOW FOR ANOTHER DAY OF FAIRLY
WARM CONDITIONS IN THE SOUTHEASTERN CWA...WITH NOTICEABLY COOLER
TEMPERATURES IN THE NORTHWESTERN CWA. WITH FORCING NOT EXPECTED TO
BE PARTICULARLY STRONG...COVERAGE AND INTENSITY OF PRECIPITATION
IS IN QUESTION. POPS TODAY RANGE FROM 70 (NW) TO 90 (SE)
PERCENT...WITH THUNDER SEEMING MOST LIKELY IN THE WARMER AIR IN
THE SOUTHEASTERN CWA. PRECIPITATION POTENTIAL APPEARS MAXIMIZED
JUST AHEAD OF A (VERY) WEAK SURFACE LOW...WHICH WILL ALLOW FOR A
LITTLE EXTRA LIFT AHEAD OF ITS TRACK (ACROSS EASTERN KENTUCKY AND
INTO WEST VIRGINIA).
ALTHOUGH THE ATMOSPHERE IS FAIRLY MOIST...THE COMBINATION OF POOR
MID-LEVEL LAPSE RATES AND COOLING CONDITIONS AT THE SURFACE WILL
SEVERELY LIMIT INSTABILITY...WITH MLCAPE VALUES LIKELY TO REMAIN
BELOW 1000 J/KG. IN FACT...USING THE RECENT HRRR RUNS AS
GUIDANCE...AREAS NORTH OF THE INTERSTATE 71 CORRIDOR MAY NOT SEE
MUCH (IF ANY) POTENTIAL FOR THUNDERSTORMS AT ALL. WITH THE WEAK
FORCING AND LACK OF ANY NOTABLE WIND SHEAR...STRONG STORMS APPEAR
FAIRLY UNLIKELY TODAY. SOME BRIEF HEAVY RAIN COULD
OCCUR IN THE SOUTHEASTERN CWA...ESPECIALLY IF THE CELLS DO NOT
MOVE QUICKLY.
THE AFTERNOON WILL END WITH THE FRONT CLEARING THE SOUTHEASTERN
CWA...BUT SOME POST-FRONTAL SHOWERS WILL BE POSSIBLE
ELSEWHERE...SO POPS WILL BE MAINTAINED INTO THE EVENING.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
A SHORTWAVE WELL BEHIND THE COLD FRONT WILL REMAIN JUST WEST OF
THE FORECAST AREA TO START THE DAY ON THURSDAY...MOVING SLOWLY
THROUGH THE REGION THROUGH EVENING. THIS WILL ALLOW FOR A
CONTINUED CHANCE OF SHOWERS IN THE SOUTHEASTERN SECTIONS OF THE
FORECAST AREA...WITH A SLIGHT CHANCE OF A THUNDERSTORM NEAR PEAK
HEATING. UNDER THE INFLUENCE OF HIGH PRESSURE...WHICH WILL STRETCH
WEST-TO-EAST ACROSS THE SOUTHERN GREAT LAKES...THE NORTHWESTERN
HALF OF THE FORECAST AREA IS LIKELY TO REMAIN DRY. NAM/GFS/ECMWF
TEMPERATURE PROJECTIONS ARE IN VERY GOOD AGREEMENT...WITH THE
WARMEST CONDITIONS (LOWER 80S) IN THE SOUTHWESTERN CWA...AND
SLIGHTLY COOLER CONDITIONS (UPPER 70S) IN THE NORTHEASTERN CWA.
ATTENTION ON FRIDAY AND GOING INTO THE WEEKEND WILL TURN TOWARD
THE DEVELOPMENT OF A LARGE MID-LEVEL TROUGH...WHICH APPEARS TO BE
MODELED MORE ENERGETICALLY ON THE 00Z RUNS EARLY THIS MORNING.
AHEAD OF THIS TROUGH...ANOTHER COLD FRONT WILL SLICE ACROSS THE
UPPER MISSISSIPPI VALLEY ON THURSDAY NIGHT INTO FRIDAY...CLEARING
THROUGH THE OHIO VALLEY ON FRIDAY NIGHT INTO SATURDAY. THIS FRONT
WILL SHAVE ROUGHLY ANOTHER 10 DEGREES OFF THE
TEMPERATURES...LEADING TO AN EXPECTATION FOR BELOW-NORMAL
CONDITIONS OVER THE WEEKEND. THE GREATEST POTENTIAL FOR
PRECIPITATION APPEARS TO BE FROM FRIDAY AFTERNOON THROUGH EARLY
SATURDAY MORNING. THE FRONTAL FORCING THIS TIME MAY BE A LITTLE
STRONGER THAN WITH THE SYSTEM TODAY (WEDNESDAY)...BUT INSTABILITY
WILL BE ALMOST COMPLETELY LACKING. IF THERE WILL BE A CHANCE FOR
THUNDER...IT MAY BE CONFINED TO THE SOUTHERN SECTIONS OF THE
FORECAST AREA...AND EVEN THIS IS NOT CERTAIN. POPS WERE INCREASED
TO 40-PERCENT ACROSS THE BOARD AS THIS SYSTEM PASSES WNW-TO-ESE
THROUGH THE CWA...AND IF THE 00Z ECMWF/GFS PROJECTIONS ARE THE
START OF THE TREND...THESE VALUES WILL HAVE TO BE INCREASED
FURTHER IN FUTURE FORECASTS. IF THE TROUGH REMAINS IN
PLACE...CONDITIONS MAY NOT COMPLETELY DRY OUT ON SATURDAY. SKY
GRIDS WERE INCREASED TO ACCOUNT FOR THIS...WITH 20-30 PERCENT
POPS MAINTAINED THROUGH THE DAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
SHOWERS WILL DIMINISH BUT NOT DISAPPEAR SUNDAY AS THE UPPER LOW
GRADUALLY LIFTS NORTHEAST. A BROAD UPPER RIDGE IS THEN INDICATED
TO PUSH ACROSS MOST OF THE CONUS BY TUESDAY...COUPLING WITH A
SURFACE HIGH TO USHER IN A PERIOD OF DRY WEATHER FOR THE OHIO
VALLEY REGION.
TEMPERATURES WILL VARY NOTABLY WITH RESPECT TO THE UNDULATING UPPER
AIR PATTERN. HIGHS ARE FORECAST TO BE NEAR NORMAL IN THE UPPER 70S
ON FRIDAY. BELOW NORMAL READINGS IN THE UPPER 60S ARE EXPECTED FOR
SATURDAY AND SUNDAY UNDER THE UPPER LOW AND ASSOCIATED CLOUDS AND
PRECIP. A RETURN TO NEAR NORMAL UPPER 70S SHOULD OCCUR BY TUESDAY IN
WARM ADVECTION ON A SOUTHWEST LOW LEVEL FLOW CIRCULATING AROUND THE
HIGH.
&&
.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
A COLD FRONT WILL SLOWLY MAKE ITS WAY SOUTHEAST THROUGH OUR REGION
TODAY. MEANWHILE...MODELS SUGGEST THAT A WEAK WAVE OF LOW PRESSURE
WILL TRY TO MOVE WEST TO EAST ALONG THE FRONTAL BOUNDARY NEAR THE
OHIO RIVER.
THE AIRMASS WILL BECOME INCREASINGLY MOIST AHEAD OF THE FRONT
TODAY. THE FORCING WITH THE FRONT...LOW...AND SOME UPPER LEVEL
ENERGY IS WEAK. THIS WILL MAKE IT DIFFICULT TO PINPOINT THE BEST
TIMING FOR SHOWERS AND EMBEDDED THUNDERSTORMS AT THE TAF SITES.
BEST COVERAGE PER HIGH RESOLUTION MODELS SEEM TO FAVOR THE EARLY
TO LATE AFTERNOON HOURS WHEN INSTABILITY WILL BE AT ITS MAXIMUM.
AS SUCH...HAD ADDED VCTS DESCRIPTORS AT ALL TAF SITES EXCEPT
DAYTON WITH TEMPO MVFR CONDITIONS IN SHOWERS. WITH THE INSTABILITY
NOT BEING OVERLY GREAT...HAVE NOT GONE WITH TEMPO TSRA ATTM. IT
SHOULD BE NOTED THAT WITH THE MOIST AIRMASS...WELL DEVELOPED
SHOWERS AND ESPECIALLY ANY THUNDERSTORMS...WILL BE CAPABLE OF
LOWER VISIBILITIES IN THE IFR/LIFR CATEGORY...SO AVIATORS SHOULD
BE AWARE OF THIS POTENTIAL.
FOR TONIGHT...THE FRONTAL BOUNDARY WILL CONTINUE ON ITS WAY TO OUR
SOUTHEAST AS THE WEAK WAVE OF LOW PRESSURE BEGINS TO TRANSFER AND
DEEPEN OVER THE MID ATLANTIC REGION. PRECIPITATION THREAT SHOULD
BE EXITING AWAY FROM THE TAF SITES BETWEEN THE 22Z AND 03Z
TIME FRAME. WILL FORECAST VFR CEILINGS/VISIBILITIES OVERNIGHT FOR
NOW...BUT THERE IS SOME SUGGESTION THAT MVFR CEILINGS COULD FORM
IN THE POST FRONTAL AIRMASS NEAR THE OHIO RIVER TOWARD THURSDAY
MORNING.
OUTLOOK...MVFR CEILINGS POSSIBLE THURSDAY MORNING. THUNDERSTORMS
POSSIBLE FRIDAY INTO FRIDAY EVENING. MVFR CEILINGS POSSIBLE AGAIN
FRIDAY NIGHT INTO SATURDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...CONIGLIO
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
304 AM CDT WED SEP 9 2015
.DISCUSSION...
SURFACE OBSERVATIONS THIS MORNING SHOW TEMPERATURES AND DEWPOINTS
IN THE 66-73 DEGREE RANGE WHICH IS SEVERAL DEGREES HIGHER THAN
YESTERDAY AT THIS TIME. CLOUD COVER IS ALSO INCREASING EARLY THIS
MORNING AS DEEPER MOISTURE...CHARACTERIZED BY PWATS AROUND 1.85
INCHES PER 00Z RAOBS AT BHM AND ATL...CONTINUES TO ADVECT
NORTHWESTWARD INTO THE MID STATE. IN FACT...LATEST RADAR IMAGERY
SHOWS LIGHT SHOWERS ALREADY DEVELOPING ACROSS NORTH ALABAMA AND
SOUTHERN TENNESSEE ON THE LEADING EDGE OF THIS DEEPER MOISTURE.
LATEST HRRR MODEL GUIDANCE EXPANDS THIS ACTIVITY THROUGHOUT THE
CWA LATER THIS MORNING INTO THE AFTERNOON...WHILE SHOWERS/STORMS
CURRENTLY APPROACHING THE MISSISSIPPI RIVER ALSO SPREAD INTO THE
AREA AS A UPPER TROUGH AXIS SHIFTS EASTWARD ACROSS THE TENNESSEE
VALLEY. THUS WILL CONTINUE LIKELY POPS FOR ALL ZONES...WITH CLOUD
COVER AND PRECIPITATION KEEPING HIGHS DOWN IN THE 80S TODAY.
SHOWERS AND STORMS WILL CONTINUE INTO TONIGHT AS H5 TROUGH AXIS
CONTINUES TO THE EAST...WITH ACTIVITY GRADUALLY SHIFTING
SOUTHEAST OUT OF THE CWA FROM THURSDAY INTO THURSDAY NIGHT AS A
WEAK COLD FRONT PUSHES SOUTHEASTWARD. A FEW SHOWERS AND MAYBE A
THUNDERSTORM APPEAR POSSIBLE ON FRIDAY...BUT A BETTER CHANCE WILL
ARRIVE FRIDAY NIGHT INTO SATURDAY AS THE FIRST STRONG COLD FRONT
OF METEOROLOGICAL FALL ARRIVES. 00Z GFS/ECMWF CONTINUE TO TREND
STRONGER WITH THE UPPER TROUGH THAT WILL FORCE THIS FRONT THROUGH
THE AREA...SO HAVE NUDGED POPS UP A TAD FRIDAY NIGHT INTO
SATURDAY. THE FIRST TASTE OF FALL IS THEN EXPECTED FOR THE REST OF
THE WEEKEND...WITH GFS FINALLY CATCHING ON TO THE ECMWF IN SHOWING
DRY WEATHER WITH SIGNIFICANTLY COOLER TEMPERATURES SOME 10 TO 15
DEGREES BELOW NORMAL FOR THIS TIME OF YEAR. BASED ON THE LATEST
LOCAL MODEL BLEND...WHICH HAS BEEN PERFORMING QUITE WELL OVER THE
PAST MONTH...HIGHS IN THE UPPER 60S AND 70S WITH LOWS IN THE UPPER
40S AND 50S ARE EXPECTED FOR SEVERAL DAYS FROM SUNDAY THROUGH AT
LEAST TUESDAY. AFTER THAT TIME...MODELS DIFFER ON WHETHER A STRONG
COASTAL TROUGH OR POSSIBLE TROPICAL CYCLONE DEVELOPS IN THE
WESTERN GULF OF MEXICO...BUT IF THIS OCCURS MOISTURE FROM THIS
SYSTEM COULD SPREAD NORTHWARD INTO THE AREA LATER NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 86 70 83 66 / 60 60 50 20
CLARKSVILLE 85 68 82 63 / 60 60 30 10
CROSSVILLE 80 66 77 63 / 70 60 60 40
COLUMBIA 86 68 81 64 / 60 60 60 20
LAWRENCEBURG 86 68 82 65 / 60 60 60 20
WAVERLY 85 68 83 64 / 60 60 40 20
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHAMBURGER
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
458 AM CDT WED SEP 9 2015
.DISCUSSION...
REGIONAL RADAR MOSAIC EARLY THIS MORNING SHOWED A COMPLEX OF
THUNDERSTORMS LOCATED ALONG THE INTERSTATE 20 CORRIDOR PUSHING
SOUTH. EARLY MORNING WATER VAPOR IMAGERY SHOWED THIS COMPLEX WAS
AIDED BY A SHORTWAVE TROUGH MOVING ACROSS NORTH TEXAS... WITH 06Z
SURFACE ANALYSIS PLACING A COLD FRONT BEHIND THESE THUNDERSTORMS
FROM WEST TEXAS INTO CENTRAL OKLAHOMA. EVENING UPPER AIR ANALYSIS
SHOWED A BROAD UPPER TROUGH SWINGING ACROSS THE SOUTHERN/CENTRAL
PLAINS AND THIS TROUGH WILL HELP PUSH THE COLD FRONT CLOSER TO THE
REGION THROUGHOUT TODAY AND TOMORROW.
FOR TODAY... THE FT. HOOD VAD WIND PROFILER SHOWS 25 TO 30 KNOTS
OF SOUTHERLY INFLOW FEEDING INTO THE THUNDERSTORM COMPLEX OVER
NORTH TEXAS EARLY THIS MORNING. THIS SHOULD HELP THESE
THUNDERSTORMS MAINTAIN THEMSELVES THROUGH THE REMAINDER OF THE
EARLY MORNING HOURS. AS LOW LEVEL INFLOW VEERS AND WEAKENS LATER
LATER THIS MORNING HOWEVER... UNCERTAINTY BEGINS TO INCREASE ON
HOW FAR SOUTH THIS COMPLEX WILL MAKE IT. SOME HIGH RESOLUTION
GUIDANCE SOLUTIONS /NOTABLY THE HRRR AND TEXAS TECH WRF/ SHOWS
OUTFLOW FROM THIS COMPLEX REACHING THE BRAZOS VALLEY LATE
MORNING/EARLY AFTERNOON. GIVEN RADAR AND SATELLITE TRENDS... THINK
AREAS NORTH OF A BRENHAM TO LIVINGSTON LINE APPEAR TO BE THE MOST
LIKELY TO SEE RAIN FROM THIS COMPLEX OR ANY ASSOCIATED OUTFLOW AND
HIGHLIGHTING THE HIGHEST POPS FOR THE DAY IN THESE AREAS. EVEN IF
THE STORMS DISSIPATE BEFORE THE OUTFLOW REACHES THE AREA...
DIABATIC HEATING MAY CONTRIBUTE TO ADDITIONAL DEVELOPMENT ALONG IT
LATER THIS AFTERNOON.
FARTHER SOUTH... CONVECTIVE TEMPERATURES NEAR 90 TODAY WILL ALSO
SUPPORT ISOLATED TO SCATTERED THUNDERSTORM DEVELOPMENT ACROSS THE
REMAINDER OF THE REGION... ESPECIALLY AS A SEA BREEZE MOVES
FARTHER INLAND. THE UPPER LOW CHURNING OVER THE NORTHERN GULF
EARLY THIS MORNING IS EXPECTED TO SHEAR OUT TODAY... DECREASING
THE SUBSIDENCE THAT HAS LIMITED MORE ROBUST COVERAGE OVER THE PAST
FEW DAYS. IF THE OUTFLOW IS ABLE TO MAKE IT FARTHER SOUTH TODAY
THAN ORIGINALLY THOUGHT... POPS ALSO WILL NEED TO BE INCREASED
FARTHER SOUTH TODAY. ADDITIONALLY... FORECAST SOUNDINGS FOR
HOUSTON THIS AFTERNOON HAVE A DISTINCT INVERTED-V SIGNATURE AND
THIS WILL SUPPORT AT LEAST AN ISOLATED GUSTY WIND THREAT FROM ANY
THUNDERSTORM THAT DEVELOPS.
THE COLD FRONT IS EXPECTED TO MAKE SLOW PROGRESS ACROSS NORTH
TEXAS TODAY... AND WITH SOME UNCERTAINTY ON WHERE OUTFLOW FROM
TODAY/S THUNDERSTORMS WILL END UP KEEPING POPS HIGHEST TONIGHT
ALONG AND NORTH OF A BRENHAM TO CLEVELAND LINE. AS PRECIPITABLE
WATER VALUES RISE TO NEAR 2 INCHES LATER TODAY AND INTO TOMORROW...
LOCALLY HEAVY RAIN WILL REMAIN POSSIBLE. OTHERWISE... EXPECT
HIGHS IN THE UPPER 80S TO LOW 90S TODAY AND LOWS IN THE 70S TO
NEAR 80 TONIGHT.
THE GREAT PLAINS UPPER TROUGH WILL CONTINUE TO SWING EAST TOWARDS
THE GREAT LAKES ON THURSDAY... WITH ITS AXIS EXTENDING OVER THE
REGION. THE COLD FRONT WILL MAKE MORE PROGRESS INTO/ STALL
SOMEWHERE ACROSS CENTRAL TEXAS ON THURSDAY AND THIS WITH ADDED
LIFT FROM A 50-60 KNOT UPPER LEVEL JET STREAK APPROACHING FROM
WEST TEXAS WILL KEEP SCATTERED TO NUMEROUS THUNDERSTORMS IN THE
FORECAST ON THURSDAY AND FRIDAY. HIGHS TO END THE WEEK WILL BE
NEAR NORMAL IN THE MID TO UPPER 80S.
HEADING INTO THE WEEKEND... A STRONG SHORTWAVE TROUGH ROTATING
AROUND THE BASE OF THE BROAD UPPER TROUGH FRIDAY/SATURDAY WILL
SEND A SECONDARY... STRONGER FRONT INTO THE REGION. THIS FRONT
LOOKS TO PUSH THROUGH THE REGION SOMETIME ON SATURDAY WITH MUCH
DRIER AIR FILTERING INTO THE AREA BEHIND IT. PRECIPITABLE WATER
VALUES WILL FALL THROUGHOUT THE DAY ON SATURDAY... BOTTOMING OUT
UNDER ONE INCH ON SUNDAY. THIS WILL ALLOW RAIN CHANCES TO TAPER
OFF FROM NORTH TO SOUTH DURING THE DAY ON SATURDAY AND PROVIDE
WHAT APPEARS TO BE A VERY PLEASANT SUNDAY IN THE MAKING. DRIER AIR
WILL ALLOW FOR OVERNIGHT LOW TEMPERATURES TO POSSIBLY FALL INTO
THE 60S SUNDAY... WITH HIGHS IN THE LOW TO MID 80S.
MEDIUM RANGE GUIDANCE CONTINUES TO SHOW THE DEVELOPMENT OF A
COASTAL TROUGH/SURFACE LOW OFF MEXICO/DEEP SOUTH TEXAS HEADING
INTO THE BEGINNING OF NEXT WEEK. WHILE STILL OFFERING SOMEWHAT
DIFFERENT SOLUTIONS... THE GFS AND THE EUROPEAN BOTH ADVERTISE A
GOOD SLUG OF TROPICAL MOISTURE ASSOCIATED WITH THIS FEATURE MAKING
ITS WAY BACK INTO THE REGION /GFS PWATS INCREASE FROM LESS THAN
ONE INCH MONDAY TO NEARLY 2 INCHES ON TUESDAY/ HEADING INTO THE
MIDDLE OF NEXT WEEK. SHOWER AND THUNDERSTORM CHANCES WILL RETURN
AS THIS SYSTEM EJECTS NORTHWARD TOWARDS THE TEXAS COAST... AND
WILL NEED TO CONTINUE TO MONITOR FOR THE POTENTIAL OF HEAVY RAIN.
HUFFMAN
&&
.MARINE...
LIGHT TO MODERATE ONSHORE FLOW WILL PERSIST THROUGH FRIDAY. PERIODS
OF UNSETTLED WEATHER CAN BE EXPECTED...ESPECIALLY THURSDAY THROUGH
SATURDAY...AS UPPER LEVEL DISTURBANCES INTERACT WITH DEEPER MOISTURE
IN THE AREA. WINDS/SEAS WILL BE HIGHER IN AND NEAR STORMS. A WEAK
FRONTAL BOUNDARY WILL PUSH INTO THE WATERS LATE FRIDAY NIGHT OR
SATURDAY MORNING WITH NORTHEAST WINDS IN ITS WAKE. A WEAK TROUGH OF
LOW PRESSURE WILL DEVELOP NEAR THE LOWER TEXAS COAST EARLY NEXT WEEK
AND THIS FEATURE WILL BRING PERIODS OF SHRA/TSRA AND A PROLONGED
PERIOD OF E-SE WINDS TO THE UPPER TEXAS COASTAL WATERS. 43
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 92 75 89 74 89 / 60 50 60 30 40
HOUSTON (IAH) 91 75 89 74 87 / 40 30 60 40 50
GALVESTON (GLS) 90 81 89 79 85 / 30 30 60 50 60
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...14
AVIATION/MARINE...43
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
434 AM CDT WED SEP 9 2015
.SHORT TERM /NOW THROUGH THURSDAY/...LATEST WATER VAPOR SATELLITE
IMAGERY SHOWS A 500MB RIDGE CENTERED OVER WEST TEXAS INTO NORTHERN
MEXICO AND A 500MB LOW OVER THE WESTERN GULF OF MEXICO. BROWNSVILLE
RADAR SHOWS VERY ISOLATED ACTIVITY ACROSS THE LOWER TEXAS GULF
WATERS THIS MORNING. THE LATEST HRRR SUGGESTS CONVECTION WILL
INCREASE ACROSS THE GULF WATERS LATER THIS MORNING. BRO SOUNDING
FROM TUESDAY EVENING INDICATES PRECIPITABLE WATER VALUES OF 2.02
INCHES. MOSTLY CLEAR SKIES AND LIGHT WINDS PREVAIL ACROSS DEEP SOUTH
TEXAS EARLY THIS MORNING. NOTE...THE SURFACE OBSERVATION FROM
EDINBURG IS NOT REPRESENTATIVE TO CURRENT WEATHER CONDITIONS.
THE COMBINATION OF THE 500MB LOW ACROSS THE WESTERN GULF OF MEXICO
AND A FRONT MOVING SOUTH OVER CENTRAL TEXAS WILL ALLOW LOW TO MID
LEVEL MOISTURE TO INCREASE ACROSS DEEP SOUTH TEXAS THROUGH THE
FORECAST PERIOD. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
WILL DEVELOP ACROSS THE EASTERN PORTIONS OF THE CWA ALONG AND AHEAD
OF THE SEABREEZE FRONT MOVING INLAND THIS AFTERNOON. THE LATEST
HRRR/GFS AND ECMWF SUGGEST AN ACTIVE SEA BREEZE TODAY WHILE THE MET
REMAINS GENERALLY DRY. WILL LEAN TOWARDS THE WETTER MAV/ECMWF MOS
POPS FOR TODAY.
DEEPER MOISTURE SHOULD SUPPORT MORE ACTIVITY ACROSS THE AREA ON
THURSDAY...ESPECIALLY ACROSS THE COASTAL WATERS AND THE RANCHLANDS.
WILL BLEND TOWARDS THE WETTER NAM/ECMWF FOR POPS AREA WIDE FOR
THURSDAY.
ANY OF THE HEAVIER OR SLOWER-MOVING SHOWERS AND THUNDERSTORMS TODAY
AND THURSDAY WILL HAVE THE POTENTIAL TO PRODUCE LOCALLY HEAVY
RAINFALL WITH NUISANCE FLOODING ON ROADS AND IN LOW-LYING
AREAS...ESPECIALLY THOSE WITH A HISTORY OF FLOODING.
HIGH TEMPERATURES TODAY WILL RANGE FROM THE LOWER 90S NEAR THE COAST
TO AROUND 100 ACROSS THE UPPER VALLEY. HIGH TEMPERATURES WILL BE A
FEW DEGREES LOWER ON THURSDAY DUE TO THE INCREASE IN CLOUDS AND RAIN
CHANCES. LOW TEMPERATURES TONIGHT WILL GENERALLY BE IN THE UPPER 70S
TO AROUND 80.
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...RATHER BUSY LONG
TERM PORTION OF THE FORECAST ANTICIPATED. DEEP TROPICAL MOISTURE
(PRECIPITABLE WATER VALUES IN EXCESS OF 2 INCHES) WILL COMBINE
WITH THE FRIDAY NIGHT PASSAGE OF A WEAK COLD FRONT...AND THE
SUBSEQUENT DEVELOPMENT AND PERSISTENCE OF AN INVERTED SURFACE
TROUGH OF LOW PRESSURE ALONG THE LOWER TEXAS COAST AFTERWARDS.
WITH PERSISTENT 500 MB TROUGHINESS ALONG THE TEXAS COASTLINE IN
ASSOCIATION WITH A CLOSED 500 MB LOW PRESSURE SYSTEM OVER THE
GREAT LAKES REGION...DEEP SOUTH TEXAS AND THE RIO GRANDE VALLEY
CAN EXPECT SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS FOR
MUCH OF THE FORECAST PERIOD...WITH THE HIGHEST RAIN CHANCES FROM
FRIDAY THROUGH SATURDAY...WHEN LOCALLY HEAVY RAINFALL HAS ALSO
BEEN INCLUDED IN THE FORECAST. THE MOST INTERESTING ASPECT OF THE
LONG TERM FORECAST PERIOD IS THE GFS` INDICATION THAT A WEAK
CLOSED AREA OF LOW PRESSURE WILL FORM OVER THE WESTERN GULF OF
MEXICO AND MOVE INLAND OVER THE BRO CWFA TOWARDS THE END OF THE
FORECAST PERIOD. ANY CLOSED AREA OF LOW PRESSURE...SHOULD IT
FORM...WOULD HAVE THE ABILITY TO RADICALLY CHANGE PRECIPITATION
AND WIND VALUES ON MONDAY AND TUESDAY...AND THIS WILL NEED TO BE
MONITORED BY SUCCESSIVE SHIFTS THROUGH THE NEXT FEW DAYS.
&&
.MARINE...NOW THROUGH THURSDAY...BUOY DATA AND OBSERVATION PLATFORMS
ALONG THE LOWER TEXAS COAST THIS MORNING INDICATE SOUTH WINDS BETWEEN
8 TO 13 KNOTS WITH SEA HEIGHTS NEAR 3 FEET ON THE GULF WATERS. A
WEAK PRESSURE GRADIENT OVER THE WESTERN GULF OF MEXICO WILL
MAINTAIN LIGHT TO MODERATE SOUTHEAST TO SOUTH WINDS AND LOW TO
MODERATE SEAS. HOWEVER...SMALL CRAFT WILL NEED TO EXERCISE CAUTION
ON THE LAGUNA MADRE THIS AFTERNOON DUE TO A SLIGHTLY STRONGER
WINDS.
THURSDAY NIGHT THROUGH TUESDAY...GENERALLY LIGHT TO MODERATE WINDS
AND LOW TO MODERATE SEAS ARE EXPECTED THROUGH THE PERIOD AS WEAK
LOW PRESSURE PERSISTS OVER THE WESTERN GULF OF MEXICO AND A COLD
FRONT INTRUDES INTO THE LOWER TEXAS COASTAL WATERS. WEAK CLOSED
LOW PRESSURE MAY DEVELOP ALONG THE LOWER TEXAS COAST TOWARDS THE
END OF THE FORECAST PERIOD PER ONE WEATHER FORECAST MODEL...BUT
THE STRONGER WINDS AND HIGHER SEAS INDICATED IN ASSOCIATION WITH
THE LOW PRESSURE DEVELOPMENT HAVE NOT BEEN INCLUDED IN THE
FORECAST AT THIS TIME.
&&
.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL 92 80 91 79 / 30 20 30 20
BROWNSVILLE 93 79 93 79 / 30 20 30 20
HARLINGEN 96 78 95 78 / 30 20 30 20
MCALLEN 98 80 97 78 / 20 10 20 20
RIO GRANDE CITY 100 78 98 77 / 10 10 30 20
SOUTH PADRE ISLAND 87 82 88 80 / 30 30 40 30
&&
.BRO WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
SHORT TERM...CACERES-63
LONG TERM...TOMASELLI-66
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
119 AM CDT WED SEP 9 2015
.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
&&
.AVIATION...LIGHT SOUTHEAST WINDS WITH A FEW PASSING CLOUDS
PREVAIL OVER DEEP SOUTH TEXAS EARLY THIS MORNING. VFR CONDITIONS
EXPECTED TO CONTINUE THROUGH MID MORNING. LOW TO MID LEVEL
MOISTURE WILL INCREASE ACROSS THE AREA TODAY AS A 500MB LOW MOVES
ACROSS THE WESTERN GULF OF MEXICO. ISOLATED TO SCATTERED SHOWERS
AND THUNDERSTORMS WILL DEVELOP ACROSS THE EASTERN PORTIONS OF THE
CWA ALONG AND AHEAD OF THE SEABREEZE FRONT MOVING INLAND THIS
AFTERNOON. LIGHT SOUTHEAST WINDS OVERNIGHT WILL BECOME MODERATE
LATER THIS MORNING WITH GUSTS AROUND 20 KNOTS IN THE AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 636 PM CDT TUE SEP 8 2015/
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
AVIATION...SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE
MOSTLY CLEAR SKIES ACROSS THE CWA EARLY THIS EVENING. EXPECT VFR
CONDITIONS TO PREVAIL THE REST OF THE EVENING INTO EARLY WED
MORNING AS NORTHERLY WINDS ALOFT CONTINUE TO PROVIDE SUBSIDENCE
ACROSS THE RIO GRANDE VALLEY. A 500MB LOW ACROSS THE NORTH CENTRAL
GULF OF MEXICO WILL MOVE ACROSS THE WESTERN GULF OF MEXICO
WEDNESDAY. THIS WILL ALLOW LOW TO MID LEVEL MOISTURE TO INCREASE
ACROSS THE COASTAL SECTIONS OF THE CWA. ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS THE EASTERN PORTIONS
OF THE CWA ALONG AND AHEAD OF THE SEABREEZE FRONT MOVING INLAND
WED AFTERNOON.
PREV DISCUSSION... /ISSUED 300 PM CDT TUE SEP 8 2015/
SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... AN ACTIVE SEA
BREEZE IS MOVING SLOWLY INLAND THIS AFTERNOON. THE HRRR SUGGESTS
THAT IT WILL PUSH INTO THE MID VALLEY. DRIER AIR IS STILL IN PLACE
FARTHER WEST. SKIES SHOULD BECOME MOSTLY CLEAR TONIGHT. WV IMAGERY
SHOWS A MID LEVEL CIRCULATION SOUTH OF LOUISIANA...WHICH IS
PROGGED TO DRIFT SOUTHWEST TOWARD THE AREA. THUS...LOOK FOR
CONTINUED UNSETTLED CONDITIONS OVER THE GULF...WITH A FEW SHOWERS
TRANSLATING FARTHER WEST OVER THE COAST TONIGHT. THE NAM SHOWS
DRIER AIR AGAIN OUT WEST ON WEDNESDAY...SO WILL ANTICIPATE SIMILAR
CONDITIONS AS TODAY WITH MAYBE A LITTLE MORE ACTIVITY OVER THE
COASTAL AREAS. THE MOISTURE POOLING ALONG AND AHEAD OF A FRONT
MOVING SOUTH OVER CENTRAL TEXAS WILL NOT BE FAR ENOUGH SOUTH TO
CAUSE A MAJOR PROBLEM IN THE SHORT TERM...EXCEPT PERHAPS FOR A FEW
SHOWERS OVER THE FAR NORTHWEST... ZAPATA COUNTY...WEDNESDAY NIGHT.
LONG TERM /THURSDAY THROUGH TUESDAY/...
H5 TROUGH REMAINS BOTTLED BETWEEN 2 RIDGES...WITH THE AXIS
REMAINING TO THE EAST ON THURSDAY. THIS WILL KEEP THE REGION ON
THE DRIER WEST SIDE THURSDAY AND INTO FRIDAY. FRIDAY BRINGS THE
TROUGH AXIS WESTWARD AS THE OVERALL TROUGH DEEPENS. AN INCREASE IN
MOISTURE FROM THE SOUTH WILL BEGIN TO RAMP UP POPS LATER FRIDAY
AFTERNOON. GOOD DEEP MOISTURE AND INSTABILITY COMBINES ON
SATURDAY FOR A GOOD CHANCES FOR SHOWERS AND THUNDERSTORMS. SUNDAY
INTO MONDAY A WEAK COLD FRONT TRIES TO MOVE SOUTHWARD INTO SOUTH
TEXAS. THE MAIN ISSUE IS SOUTHWARD MOVING DRIER AIR AND HOW FAR
SOUTH IT WILL REACH...CLASHING WITH GULF MOISTURE MOVING BACK TO
THE NORTH. CONTINUING WITH A GOOD CHANCE FOR THUNDERSTORMS BOTH
DAYS AS INSTABILITY REMAINS DECENT. QUESTION MARKS CROP UP
STARTING EARLY NEXT WEEK AS MODELS DIFFER ON WHAT HAPPENS TO THE
REMNANTS OF THE FRONT. NEEDLESS TO SAY...A DEGRADING FRONT
HOVERING IN THE WESTERN GULF NEEDS TO HAVE A CLOSE EYE KEPT ON IT.
FOR NOW...THE LOCALIZED INSTABILITY RAIN CHANCES CONTINUE TUESDAY
INTO WEDNESDAY...ESPECIALLY CLOSER TO THE COAST...AS WE MOVE INTO
OUR CLIMATOLOGICALLY WETTEST WEEK OF THE ENTIRE YEAR.
MARINE...
A WEAK PRESSURE GRADIENT WILL CAUSE LIGHT TO MODERATE SOUTHEAST
TO SOUTH WINDS AND LOW TO MODERATE SEAS TO PERSIST ALONG THE LOWER
TEXAS COAST.
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
63
AREA FORECAST DISCUSSION
National Weather Service Dodge City KS
702 AM CDT WED SEP 9 2015
...Updated for aviation discussion...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 313 AM CDT WED SEP 9 2015
The main forecast challenge for early this morning is areas of fog,
and or stratus and how dense. Moist weak northeasterly upslope flow
and with clear skies is allowing for good radiational cooling, and
causing areas of ground fog to develop and some stratus. Will carry
areas of fog in most areas this morning, but may need a dense fog
advisory in places especially near and west of Dodge City where the
NAM and the RAP model shows the highest boundary layer relative
humidity. The HRRR model also shows patchy dense fog in the
Garden City area. After the fog burns off by mid morning, expect
clearing skies and highs in the mid 80s. A surface high pressure
ridge will move east while a trough of low pressure develops in
the lee of the Rockies. Light and variable winds this morning
will become southeast to southerly at 10 mph with 10 to 20 mph far
west.
For tonight, expect mainly clear skies. A few thunderstorms could
develop late across the I-70 corridor as a jet streak moves in. Will
carry some small chances for rainfall, towards dawn. Overnight lows
will be in the lower 60s with light southeast winds becoming south
around 8 to 12 mph.
.LONG TERM...(Thursday THROUGH Tuesday)
ISSUED AT 339 AM CDT WED SEP 9 2015
For Thursday, an upper level shortwave trough in northwest flow
aloft will move across western Kansas pushing a cold front to near
Hays to Garden City and Elkhart by late afternoon. Ahead of the cold
front, warmer and moist south winds of 15 to 25 mph, will push highs
to around 90. Most models have thunderstorms developing by afternoon
ahead of the cold front, with a possible MCS (Mesoscale Convective
Complex) developing near and east of Dodge City by late afternoon
and evening. The cold front will continue to push across western
Kansas overnight with numerous thunderstorms developing. Some low
stratus is also suggested towards dawn behind the cold front.
Will carry around 50 percent chances in the afternoon and evening
with lesser chances north of Garden City where dewpoints are much
lower. Forecast instability is around 2000-3000 J/KG, but the NAM
is much higher and with dewpoints in the upper 60s. With 30kt at
mid levels and around 50 to 60kt aloft there could be some severe
thunderstorms with large hail from quarter to half dollar size,
and strong winds over 60 mph.
For Friday into next Tuesday, a dry period is forecast. A large
upper level trough will continue to dig into the Upper Midwest and
Mississippi Valley with much cooler surface high pressure moving
into the Plains. Highs on Friday and Saturday will be in the mid to
upper 70s. As the upper trough moves away from the region Sunday
into Tuesday, a warming trend will move back into the High Plains
with highs in the low 80s on Sunday, then mid to upper 80s on Monday
and Tuesday. Overnight lows will be in the 50s into Sunday morning,
the gradually warm to 60 to 65 degrees on Monday and Tuesday morning.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z Thursday MORNING)
ISSUED AT 659 AM CDT WED SEP 9 2015
Weak surface high pressure will move off to the east and be
replaced by a surface trough in the lee of the Rockies. This will
result in light winds becoming south at 5 to 10 mph this
afternoon. Dense fog this morning at KDDC/KGCK will rapidly clear
by 15z with daytime heating, leaving VFR conditions for the
remainder of the period.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 85 62 89 60 / 0 10 40 40
GCK 85 61 90 59 / 0 0 30 30
EHA 87 63 91 60 / 10 10 20 20
LBL 86 62 92 61 / 0 10 30 40
HYS 87 61 89 60 / 0 20 30 30
P28 85 63 89 64 / 0 10 20 50
&&
.DDC Watches/Warnings/Advisories...
Dense Fog Advisory until 9 AM CDT /8 AM MDT/ this morning for
KSZ043>045-061>066-074>081-084>090.
&&
$$
SHORT TERM...Kruse
LONG TERM...Kruse
AVIATION...Finch
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1019 AM EDT WED SEP 9 2015
.SYNOPSIS...
SUMMER LIKE HEAT WILL BE IN PLACE TODAY WITH SCATTERED
THUNDERSTORMS...MOST NUMEROUS ALONG THE COAST. CLOUDS AND RAIN
CHANCES THEN INCREASE LATE IN THE WEEK WITH THE SLOW APPROACH OF A
COLD FRONT. THIS BOUNDARY MAY NOT PUSH THROUGH UNTIL MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 10 AM WEDNESDAY...THE SHORTWAVE MOVING UP THE CAROLINA COAST
IS PRODUCING A LINE OF SHOWERS AND THUNDERSTORMS THAT IS QUICKLY
MOVING ACROSS SOUTHEAST NORTH CAROLINA.
THE ATMOSPHERE CONTINUES TO BE VERY MOIST WITH PRECIPITABLE WATER
AROUND 2 INCHES ALONG THE COAST. THE 12 UTC HRRR IS SHOWING THE
INITIAL BAND OF CONVECTION SHIFTING TO THE NORTHEAST WITH
ADDITIONAL CONVECTION DEVELOPING AROUND 15 UTC ALONG OUR ENTIRE
COAST BUT QUICKLY ENDING BY MID-AFTERNOON AS THE SUBSIDENCE AND
SLIGHTLY DRIER AIR WORKS ITS WAY BEHIND THE SHORTWAVE.
WITH WARMER TEMPERATURES ALOFT AND CLEARING SKIES WILL PUSH
TEMPERATURES INTO THE LOWER 90S INLAND WITH UPPER 80S ON THE
COAST. THIS IS STILL 5 OR MORE DEGREES AWAY FROM RECORDS. WITH
DEWPOINTS REMAINING IN THE LOWER TO MID 70S HEAT INDEX VALUES
SHOULD REACH 100 DEGREES ACROSS PARTS OF THE PEE DEE REGION.
TONIGHT ANOTHER UPPER DISTURBANCE TAKING A MORE INLAND TRACK COULD
SPREAD EVENING SHOWERS AND STORMS ACROSS THE I-95 CORRIDOR. I HAVE
NOT GONE TOO HIGH WITH POPS HOWEVER GIVEN THE COOLING/STABILIZING
BOUNDARY LAYER AND THE BEST LIFT WITH THE DISTURBANCE EXPECTED TO
PASS ACROSS CENTRAL AND WESTERN NORTH CAROLINA. AS LOW LEVEL WINDS
TURN SOUTHWESTERLY A MODEST LOW LEVEL JET SHOULD DEVELOP WITH 975 MB
(1000 FOOT AGL) WINDS INCREASING TO 20-25 KT. THIS SHOULD HELP KEEP
A STRONG NOCTURNAL INVERSION FROM DEVELOPING AND LOWS SHOULD ONLY
FALL TO 72-75 INLAND AND 75-78 AT THE COAST...ABOUT 7 DEGREES ABOVE
NORMAL FOR THE DATE.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY... PREFRONTAL TROUGH MOVES INTO THE CAROLINAS
AND STALLS ON THURSDAY. AHEAD OF THIS FEATURE THERE SHOULD BE AMPLE
MOISTURE FOR AT LEAST SCATTERED CONVECTIVE COVERAGE. MID LEVEL
FORCING IN THE FORM OF VORT MAXES COME LATE IN THE DAY AND AT NIGHT
PREVENTING THE NORMAL DIURNAL DYING OFF OF RADAR COVERAGE EVEN
THOUGH DEEP CONVECTION MAY BE HARDER TO COME BY DUE TO THE DECREASE
IN INSTABILITY. THIS BOUNDARY WEAKENS AND MOVES OFFSHORE BY FRIDAY
AND WAS PREVIOUSLY TO BE REPLACED BY A LEGITIMATE COLD FRONT. THIS
FRONT NOW APPEARS SLOWER LEAVING NOT MUCH IN THE WAY OF SURFACE
FEATURES IN PLACE LOCALLY. FURTHER COMPLICATING FRIDAY FORECAST IS
THE DIFFERENCE IN TIMING AMONGST MODELS WITH RESPECT TO SOME MID
LEVEL IMPULSES. IN THE END DID NOT MAKE MUCH CHANGE AND WILL ONCE
AGAIN CARRY CHANCE POPS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY... IMPRESSIVELY DEEP UPPER TROUGH DRIVES COLD
FRONT INTO THE COASTAL PLAIN ON SATURDAY. BEING ALIGNED WITH THE FLOW
ALOFT IT WILL STALL ON SUNDAY. SATURDAY OFFERS THE DEEPEST MOISTURE
AND WILL LIKELY PAN OUT BEING A VERY UNSETTLED DAY WITH PERHAPS
NUMEROUS SHOWERS AND IF THE DIURNAL TIMING IS RIGHT STRONGER
THUNDERSTORMS. MODELS AT SOME ODDS REGARDING THE DEPTH AND TILT OF
THE UPPER WAVE AND UNTIL IT ENTERS THE UPPER AIR NETWORK ITS HARD TO
SPECULATE WHICH IS CORRECT. ON SUNDAY THE DEEP MOISTURE GETS SHUNTED
OFFSHORE BUT SOME LOW LEVEL MOISTURE ALONG THE BOUNDARY WILL STILL
CALL FOR SOME LOW RAIN CHANCES MAINLY ALONG THE COAST. COOLER AND
DRYER AIR NOW APPEARS TO ARRIVE FASTER AND SHOULD BE ADVECTING IN
MODERATELY STRONGLY BY MONDAY. COOLER WEATHER WILL LAST INTO TUESDAY
AS THE CENTER OF THE LARGE HIGH BUILDS TO OUR NORTH.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
AS OF 12Z...SHOWERS ARE MOVING TOWARD THE MYRTLES AND THE HRRR MODEL
INITIALIZED WELL WITH THIS. ONLY A LITTLE BIT OF HEATING TODAY WILL
KICK OFF MORE SHOWERS AS THE LFC IS FAIRLY LOW. LOOK FOR CONVECTION
TO MOVE INTO ILM BY MID MORNING WITH THUNDER A DECENT BET. MAINLY
MVFR CEILINGS WITH TEMPO IFR VISIBILITIES IN THE HEAVIER RAIN.
INLAND...DENSE FOG WILL PERSIST THROUGH AT LEAST 14Z WITH GRADUAL
IMPROVEMENT TO VFR BY 15-16Z. SOME CONVECTION WILL ALSO MOVE INTO
THIS REGION IN THE AFTERNOON...HOWEVER COVERAGE WILL NOT BE A
WIDESPREAD AS THE COAST WHICH WILL HAVE THE RESULTANT BOUNDARY TO
WORK WITH.
EXTENDED OUTLOOK...SCATTERED CONVECTION ON THURSDAY WITH POSSIBLE
NUMEROUS STORMS FRIDAY AND SATURDAY. STORMS ENDING SUNDAY MORNING
WITH COOLER CONDITIONS INTO MONDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 10 AM WEDNESDAY...SOUTH-SOUTHWEST WINDS OF 10 KTS WITH SEAS
OF 2 TO 2.5 FEET THIS MORNING ARE OCCURRING OVER THE COASTAL
WATERS. HIGH PRESSURE WILL SLOWLY LESSEN ITS IMPACT BY THIS
EVENING AS A COLD FRONT WELL TO THE WEST MOVES CLOSER TO THE
CAROLINAS. WINDS ARE EXPECTED TO SHIFT MORE TO THE SOUTHWEST AND
INCREASE TO 10 TO 15 KNOTS. SEAS WILL GRADUALLY INCREASE TO 3
FEET.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY... A PREFRONTAL TROUGH WILL BOOST WIND AND
SEAS ON THURSDAY. WE ARE NOT ANTICIPATING HEADLINES OR ADVISORIES,
BUT ITS BEEN FAIRLY QUIET SO THURSDAY WILL BE MORE UNSETTLED THAN
THE PAST FEW DAYS WITH THE ADVENT OF SOME 4 FT SEAS. ON FRIDAY
THIS BOUNDARY MOVES OFFSHORE AND WEAKENS IF NOT DISSIPATE
ALTOGETHER. THE 20KT GUSTINESS SHOULD DROP OUT OF THE FORECAST AS
WILL ANY 4 FT WAVES. A COLD FRONT WILL ALSO BE APPROACHING FROM
THE NW ON FRIDAY BUT IT NOW LOOKS SLOWER THAN PREVIOUSLY FORECAST.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3 AM WEDNESDAY... WITH THE SLOWER ARRIVAL OF COLD FRONT ON
SATURDAY THE AREA MAY STAY IN AN INCREASED GRADIENT PRE-FRONTAL FLOW
REGIME. AS SUCH WIND SPEEDS MAY NEED TO BE RE-EVALUATED AND RAISED
ESPECIALLY AS SOME HIGHER MID LEVEL WINDS MAY BE IMPINGING UPON THE
AREA. THE UPPER WAVE DRIVING THIS SYSTEM IS FAR FROM BEING SAMPLED
BY THE UPPER AIR NETWORK HOWEVER AND SO NO LARGE CHANGES WILL BE
MADE AT THIS TIME. SHOULD THINGS KEEP SLOWING DOWN THEN A SW WIND
WILL REMAIN ON SUNDAY AS THE BOUNDARY EITHER STALLS ALONG THE COAST
OR PERHAPS JUST INLAND. EITHER WAY THE STRONGER GRADIENT WILL HAVE
PUSHED FURTHER OFFSHORE AND THE POSSIBILITY OF HIGHER WINDS AND SEAS
THAN THE CURRENT FORECAST ALONG WITH IT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HAWKINS/TRA
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...HDL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
642 AM EDT WED SEP 9 2015
.SYNOPSIS...
SUMMERLIKE HEAT WILL BE IN PLACE TODAY WITH SCATTERED
THUNDERSTORMS...MOST NUMEROUS ALONG THE COAST. CLOUDS AND RAIN
CHANCES THEN INCREASE LATE IN THE WEEK WITH THE SLOW APPROACH OF A
COLD FRONT. THIS BOUNDARY MAY NOT PUSH THROUGH UNTIL MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 645 AM WEDNESDAY...SURFACE HIGH PRESSURE NORTH OF BERMUDA WILL
PROVIDE A WARM AND HUMID AIRMASS TO THE CAROLINAS TODAY STRAIGHT OUT
OF THE BAHAMAS. 850 MB TEMP EXPECTED TO HOVER AROUND +18C IS NEAR
THE 95TH PERCENTILE FOR CLIMATOLOGICAL READINGS THIS TIME OF YEAR AT
CHS. AS A RESULT WE SHOULD SEE HIGH TEMPERATURES RISE INTO THE LOWER
90S INLAND WITH UPPER 80S ON THE COAST. THIS IS STILL 5 OR MORE
DEGREES AWAY FROM RECORDS. WITH DEWPOINTS REMAINING IN THE LOWER TO
MID 70S HEAT INDEX VALUES SHOULD REACH 100 DEGREES ACROSS PARTS OF
THE PEE DEE REGION.
AN UPPER DISTURBANCE CURRENTLY MOVING NORTHEASTWARD THROUGH COASTAL
SOUTH CAROLINA IS HELPING SUPPORT A CLUSTER OF SHOWERS &
THUNDERSTORMS NEAR GEORGETOWN/MURRELLS INLET. THIS DISTURBANCE
SHOULD MOVE THROUGH MYRTLE BEACH AFTER SUNRISE...REACHING SE NORTH
CAROLINA BY LATE THIS MORNING. HIGH RES MODELS INCLUDING THE NSSL
WRF...THE LATEST SEVERAL HRRR RUNS...AND THE ARW AND NMM VERSIONS OF
THE WRF ALL SUPPORT THE IDEA OF CONVECTION BECOMING MORE WIDESPREAD
ACROSS SE NORTH CAROLINA AROUND 14-15Z (10-11 AM) AS THE UPPER
DISTURBANCE ENCOUNTERS AN UNCAPPED AIRMASS WITH SURFACE-BASED CAPE
IN EXCESS OF 2000 J/KG. I HAVE INCREASED POPS TO 40-60 PERCENT IN
THE CAPE FEAR REGION...WITH POPS ELSEWHERE IN THE 10-30 PERCENT
RANGE GIVEN PROBABLE SUBSIDENCE AND MID-LEVEL DRYING BEHIND THE
UPPER DISTURBANCE. CONVECTION SHOULD TEND TO MOVE NORTHEASTWARD
DURING THE MID TO LATE AFTERNOON...FOLLOWING THE DISTURBANCE INTO
FAR-EASTERN NORTH CAROLINA.
TONIGHT ANOTHER UPPER DISTURBANCE TAKING A MORE INLAND TRACK COULD
SPREAD EVENING SHOWERS AND STORMS ACROSS THE I-95 CORRIDOR. I HAVE
NOT GONE TOO HIGH WITH POPS HOWEVER GIVEN THE COOLING/STABILIZING
BOUNDARY LAYER AND THE BEST LIFT WITH THE DISTURBANCE EXPECTED TO
PASS ACROSS CENTRAL AND WESTERN NORTH CAROLINA. AS LOW LEVEL WINDS
TURN SOUTHWESTERLY A MODEST LOW LEVEL JET SHOULD DEVELOP WITH 975 MB
(1000 FOOT AGL) WINDS INCREASING TO 20-25 KT. THIS SHOULD HELP KEEP
A STRONG NOCTURNAL INVERSION FROM DEVELOPING AND LOWS SHOULD ONLY
FALL TO 72-75 INLAND AND 75-78 AT THE COAST...ABOUT 7 DEGREES ABOVE
NORMAL FOR THE DATE.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY... PREFRONTAL TROUGH MOVES INTO THE CAROLINAS
AND STALLS ON THURSDAY. AHEAD OF THIS FEATURE THERE SHOULD BE AMPLE
MOISTURE FOR AT LEAST SCATTERED CONVECTIVE COVERAGE. MID LEVEL
FORCING IN THE FORM OF VORT MAXES COME LATE IN THE DAY AND AT NIGHT
PREVENTING THE NORMAL DIURNAL DYING OFF OF RADAR COVERAGE EVEN
THOUGH DEEP CONVECTION MAY BE HARDER TO COME BY DUE TO THE DECREASE
IN INSTABILITY. THIS BOUNDARY WEAKENS AND MOVES OFFSHORE BY FRIDAY
AND WAS PREVIOUSLY TO BE REPLACED BY A LEGITIMATE COLD FRONT. THIS
FRONT NOW APPEARS SLOWER LEAVING NOT MUCH IN THE WAY OF SURFACE
FEATURES IN PLACE LOCALLY. FURTHER COMPLICATING FRIDAY FORECAST IS
THE DIFFERENCE IN TIMING AMONGST MODELS WITH RESPECT TO SOME MID
LEVEL IMPULSES. IN THE END DID NOT MAKE MUCH CHANGE AND WILL ONCE
AGAIN CARRY CHANCE POPS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY... IMPRESSIVELY DEEP UPPER TROUGH DRIVES COLD
FRONT INTO THE COASTAL PLAIN ON SATURDAY. BEING ALIGNED WITH THE FLOW
ALOFT IT WILL STALL ON SUNDAY. SATURDAY OFFERS THE DEEPEST MOISTURE
AND WILL LIKELY PAN OUT BEING A VERY UNSETTLED DAY WITH PERHAPS
NUMEROUS SHOWERS AND IF THE DIURNAL TIMING IS RIGHT STRONGER
THUNDERSTORMS. MODELS AT SOME ODDS REGARDING THE DEPTH AND TILT OF
THE UPPER WAVE AND UNTIL IT ENTERS THE UPPER AIR NETWORK ITS HARD TO
SPECULATE WHICH IS CORRECT. ON SUNDAY THE DEEP MOISTURE GETS SHUNTED
OFFSHORE BUT SOME LOW LEVEL MOISTURE ALONG THE BOUNDARY WILL STILL
CALL FOR SOME LOW RAIN CHANCES MAINLY ALONG THE COAST. COOLER AND
DRYER AIR NOW APPEARS TO ARRIVE FASTER AND SHOULD BE ADVECTING IN
MODERATELY STRONGLY BY MONDAY. COOLER WEATHER WILL LAST INTO TUESDAY
AS THE CENTER OF THE LARGE HIGH BUILDS TO OUR NORTH.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 12Z...SHOWERS ARE MOVING TOWARD THE MYRTLES AND THE HRRR MODEL
INITIALIZED WELL WITH THIS. ONLY A LITTLE BIT OF HEATING TODAY WILL
KICK OFF MORE SHOWERS AS THE LFC IS FAIRLY LOW. LOOK FOR CONVECTION
TO MOVE INTO ILM BY MID MORNING WITH THUNDER A DECENT BET. MAINLY
MVFR CEILINGS WITH TEMPO IFR VISIBILITIES IN THE HEAVIER RAIN.
INLAND...DENSE FOG WILL PERSIST THROUGH AT LEAST 14Z WITH GRADUAL
IMPROVEMENT TO VFR BY 15-16Z. SOME CONVECTION WILL ALSO MOVE INTO
THIS REGION IN THE AFTERNOON...HOWEVER COVERAGE WILL NOT BE A
WIDESPREAD AS THE COAST WHICH WILL HAVE THE RESULTANT BOUNDARY TO
WORK WITH.
EXTENDED OUTLOOK...SCATTERED CONVECTION ON THURSDAY WITH POSSIBLE
NUMEROUS STORMS FRIDAY AND SATURDAY. STORMS ENDING SUNDAY MORNING
WITH COOLER CONDITIONS INTO MONDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 645 AM WEDNESDAY...HIGH PRESSURE NORTH OF BERMUDA WILL BE OUR
CONTROLLING WEATHER SYSTEM THROUGH TONIGHT. TODAY`S SOUTH WINDS WILL
VEER MORE SOUTHWESTERLY TONIGHT AS A COLD FRONT...CURRENTLY MOVING
SE ACROSS ILLINOIS AND WISCONSIN...MOVES INTO WEST VIRGINIA AND
KENTUCKY. AN UPPER LEVEL DISTURBANCE CURRENTLY MOVING NORTHEASTWARD
ACROSS COASTAL SOUTH CAROLINA WILL SPREAD SCATTERED SHOWERS ALONG
THE NORTHEASTERN SOUTH CAROLINA COAST THIS MORNING. LATEST HIGH-RES
MODELS INDICATE COVERAGE OF STORMS WILL EXPAND ONCE THE DISTURBANCE
REACHES SOUTHEASTERN NORTH CAROLINA LATE THIS MORNING. STEERING
WINDS IN THE ATMOSPHERE WILL TEND TO PUSH STORMS NORTHEASTWARD AT 10
MPH...HOWEVER ASSUMING ENOUGH STORMS FORM COLLIDING OUTFLOW
BOUNDARIES WILL ULTIMATELY DETERMINE WHERE STORMS MOVE. MARINERS IN
THE CAPE FEAR AREA WILL WANT TO KEEP AN EYE ON THE SKY LATE THIS
MORNING AND EARLY THIS AFTERNOON.
SEAS CURRENTLY AROUND 2 FEET WILL BUILD CLOSER TO 3 FEET LATE THIS
AFTERNOON AS WIND SPEEDS INCREASE WITH THE SEABREEZE. SW WINDS
WILL INCREASE TO NEAR 15 KT TONIGHT.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY... A PREFRONTAL TROUGH WILL BOOST WIND AND SEAS
ON THURSDAY. WE ARE NOT ANTICIPATING HEADLINES OR ADVISORIES, BUT
ITS BEEN FAIRLY QUIET SO THURSDAY WILL BE MORE UNSETTLED THAN THE
PAST FEW DAYS WITH THE ADVENT OF SOME 4 FT SEAS. ON FRIDAY THIS
BOUNDARY MOVES OFFSHORE AND WEAKENS IF NOT DISSIPATE ALTOGETHER. THE
20KT GUSTINESS SHOULD DROP OUT OF THE FORECAST AS WILL ANY 4 FT
WAVES. A COLD FRONT WILL ALSO BE APPROACHING FROM THE NW ON FRIDAY
BUT IT NOW LOOKS SLOWER THAN PREVIOUSLY FORECAST.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3 AM WEDNESDAY... WITH THE SLOWER ARRIVAL OF COLD FRONT ON
SATURDAY THE AREA MAY STAY IN AN INCREASED GRADIENT PRE-FRONTAL FLOW
REGIME. AS SUCH WIND SPEEDS MAY NEED TO BE RE-EVALUATED AND RAISED
ESPECIALLY AS SOME HIGHER MID LEVEL WINDS MAY BE IMPINGING UPON THE
AREA. THE UPPER WAVE DRIVING THIS SYSTEM IS FAR FROM BEING SAMPLED
BY THE UPPER AIR NETWORK HOWEVER AND SO NO LARGE CHANGES WILL BE
MADE AT THIS TIME. SHOULD THINGS KEEP SLOWING DOWN THEN A SW WIND
WILL REMAIN ON SUNDAY AS THE BOUNDARY EITHER STALLS ALONG THE COAST
OR PERHAPS JUST INLAND. EITHER WAY THE STRONGER GRADIENT WILL HAVE
PUSHED FURTHER OFFSHORE AND THE POSSIBILITY OF HIGHER WINDS AND SEAS
THAN THE CURRENT FORECAST ALONG WITH IT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MBB
NEAR TERM...TRA
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...DL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
657 AM EDT WED SEP 9 2015
.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE REGION TODAY THROUGH
TONIGHT...BRINGING OCCASIONAL SHOWERS AND A CHANCE OF A FEW
THUNDERSTORMS. COOLER AIR WILL SETTLE IN BEHIND THIS FRONT BY
THURSDAY. ANOTHER FRONT WILL MOVE THROUGH THE REGION ON
FRIDAY...WITH EVEN COOLER CONDITIONS EXPECTED FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS HIGH PRESSURE SOUTHEAST OF THE OHIO VALLEY LOSES ITS INFLUENCE
OVER THE REGION...A TRANSITION IN WEATHER PATTERN IS UNDERWAY.
SURFACE OBSERVATIONS AT 07Z PLACE A COLD FRONT ALONG AN AXIS FROM
BAD AXE MICHIGAN TO SPRINGFIELD ILLINOIS. WHAT THIS FRONT WILL
EVENTUALLY USHER IN OVER THE NEXT DAY OR SO IS A 10-12 DEGREE DROP
IN TEMPERATURES...ALONG WITH LESS HUMID CONDITIONS.
WHAT THE FRONT LACKS IS MUCH IN THE WAY OF FOCUS...STRENGTH...OR
SPEED. IT WILL TAKE MOST OF THE DAY FOR THE SURFACE FRONT TO CROSS
THE FORECAST AREA...WHICH WILL ALLOW FOR ANOTHER DAY OF FAIRLY
WARM CONDITIONS IN THE SOUTHEASTERN CWA...WITH NOTICEABLY COOLER
TEMPERATURES IN THE NORTHWESTERN CWA. WITH FORCING NOT EXPECTED TO
BE PARTICULARLY STRONG...COVERAGE AND INTENSITY OF PRECIPITATION
IS IN QUESTION. POPS TODAY RANGE FROM 70 (NW) TO 90 (SE)
PERCENT...WITH THUNDER SEEMING MOST LIKELY IN THE WARMER AIR IN
THE SOUTHEASTERN CWA. PRECIPITATION POTENTIAL APPEARS MAXIMIZED
JUST AHEAD OF A (VERY) WEAK SURFACE LOW...WHICH WILL ALLOW FOR A
LITTLE EXTRA LIFT AHEAD OF ITS TRACK (ACROSS EASTERN KENTUCKY AND
INTO WEST VIRGINIA).
ALTHOUGH THE ATMOSPHERE IS FAIRLY MOIST...THE COMBINATION OF POOR
MID-LEVEL LAPSE RATES AND COOLING CONDITIONS AT THE SURFACE WILL
SEVERELY LIMIT INSTABILITY...WITH MLCAPE VALUES LIKELY TO REMAIN
BELOW 1000 J/KG. IN FACT...USING THE RECENT HRRR RUNS AS
GUIDANCE...AREAS NORTH OF THE INTERSTATE 71 CORRIDOR MAY NOT SEE
MUCH (IF ANY) POTENTIAL FOR THUNDERSTORMS AT ALL. WITH THE WEAK
FORCING AND LACK OF ANY NOTABLE WIND SHEAR...STRONG STORMS APPEAR
FAIRLY UNLIKELY TODAY. SOME BRIEF HEAVY RAIN COULD
OCCUR IN THE SOUTHEASTERN CWA...ESPECIALLY IF THE CELLS DO NOT
MOVE QUICKLY.
THE AFTERNOON WILL END WITH THE FRONT CLEARING THE SOUTHEASTERN
CWA...BUT SOME POST-FRONTAL SHOWERS WILL BE POSSIBLE
ELSEWHERE...SO POPS WILL BE MAINTAINED INTO THE EVENING.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
A SHORTWAVE WELL BEHIND THE COLD FRONT WILL REMAIN JUST WEST OF
THE FORECAST AREA TO START THE DAY ON THURSDAY...MOVING SLOWLY
THROUGH THE REGION THROUGH EVENING. THIS WILL ALLOW FOR A
CONTINUED CHANCE OF SHOWERS IN THE SOUTHEASTERN SECTIONS OF THE
FORECAST AREA...WITH A SLIGHT CHANCE OF A THUNDERSTORM NEAR PEAK
HEATING. UNDER THE INFLUENCE OF HIGH PRESSURE...WHICH WILL STRETCH
WEST-TO-EAST ACROSS THE SOUTHERN GREAT LAKES...THE NORTHWESTERN
HALF OF THE FORECAST AREA IS LIKELY TO REMAIN DRY. NAM/GFS/ECMWF
TEMPERATURE PROJECTIONS ARE IN VERY GOOD AGREEMENT...WITH THE
WARMEST CONDITIONS (LOWER 80S) IN THE SOUTHWESTERN CWA...AND
SLIGHTLY COOLER CONDITIONS (UPPER 70S) IN THE NORTHEASTERN CWA.
ATTENTION ON FRIDAY AND GOING INTO THE WEEKEND WILL TURN TOWARD
THE DEVELOPMENT OF A LARGE MID-LEVEL TROUGH...WHICH APPEARS TO BE
MODELED MORE ENERGETICALLY ON THE 00Z RUNS EARLY THIS MORNING.
AHEAD OF THIS TROUGH...ANOTHER COLD FRONT WILL SLICE ACROSS THE
UPPER MISSISSIPPI VALLEY ON THURSDAY NIGHT INTO FRIDAY...CLEARING
THROUGH THE OHIO VALLEY ON FRIDAY NIGHT INTO SATURDAY. THIS FRONT
WILL SHAVE ROUGHLY ANOTHER 10 DEGREES OFF THE
TEMPERATURES...LEADING TO AN EXPECTATION FOR BELOW-NORMAL
CONDITIONS OVER THE WEEKEND. THE GREATEST POTENTIAL FOR
PRECIPITATION APPEARS TO BE FROM FRIDAY AFTERNOON THROUGH EARLY
SATURDAY MORNING. THE FRONTAL FORCING THIS TIME MAY BE A LITTLE
STRONGER THAN WITH THE SYSTEM TODAY (WEDNESDAY)...BUT INSTABILITY
WILL BE ALMOST COMPLETELY LACKING. IF THERE WILL BE A CHANCE FOR
THUNDER...IT MAY BE CONFINED TO THE SOUTHERN SECTIONS OF THE
FORECAST AREA...AND EVEN THIS IS NOT CERTAIN. POPS WERE INCREASED
TO 40-PERCENT ACROSS THE BOARD AS THIS SYSTEM PASSES WNW-TO-ESE
THROUGH THE CWA...AND IF THE 00Z ECMWF/GFS PROJECTIONS ARE THE
START OF THE TREND...THESE VALUES WILL HAVE TO BE INCREASED
FURTHER IN FUTURE FORECASTS. IF THE TROUGH REMAINS IN
PLACE...CONDITIONS MAY NOT COMPLETELY DRY OUT ON SATURDAY. SKY
GRIDS WERE INCREASED TO ACCOUNT FOR THIS...WITH 20-30 PERCENT
POPS MAINTAINED THROUGH THE DAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
SHOWERS WILL DIMINISH BUT NOT DISAPPEAR SUNDAY AS THE UPPER LOW
GRADUALLY LIFTS NORTHEAST. A BROAD UPPER RIDGE IS THEN INDICATED
TO PUSH ACROSS MOST OF THE CONUS BY TUESDAY...COUPLING WITH A
SURFACE HIGH TO USHER IN A PERIOD OF DRY WEATHER FOR THE OHIO
VALLEY REGION.
TEMPERATURES WILL VARY NOTABLY WITH RESPECT TO THE UNDULATING UPPER
AIR PATTERN. HIGHS ARE FORECAST TO BE NEAR NORMAL IN THE UPPER 70S
ON FRIDAY. BELOW NORMAL READINGS IN THE UPPER 60S ARE EXPECTED FOR
SATURDAY AND SUNDAY UNDER THE UPPER LOW AND ASSOCIATED CLOUDS AND
PRECIP. A RETURN TO NEAR NORMAL UPPER 70S SHOULD OCCUR BY TUESDAY IN
WARM ADVECTION ON A SOUTHWEST LOW LEVEL FLOW CIRCULATING AROUND THE
HIGH.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
A COLD FRONT WILL SLOWLY MAKE ITS WAY SOUTHEAST THROUGH OUR REGION
TODAY. MEANWHILE...MODELS SUGGEST THAT A WEAK WAVE OF LOW PRESSURE
WILL TRY TO MOVE WEST TO EAST ALONG THE FRONTAL BOUNDARY NEAR THE
OHIO RIVER.
THE AIRMASS WILL BECOME INCREASINGLY MOIST AHEAD OF THE FRONT
TODAY. THE FORCING WITH THE FRONT...LOW...AND SOME UPPER LEVEL
ENERGY IS WEAK. THIS WILL MAKE IT DIFFICULT TO PINPOINT THE BEST
TIMING FOR SHOWERS AND EMBEDDED THUNDERSTORMS. BEST COVERAGE PER
HIGH RESOLUTION MODELS SEEM TO FAVOR THE PERIOD FROM EARLY
AFTERNOON TO THE EARLY EVENING HOURS WHEN INSTABILITY WILL BE AT
ITS MAXIMUM. IN THIS UPDATE...IT APPEARS THAT THE THREAT FOR
THUNDER WILL OCCUR ALONG AND SOUTHEAST OF THE SLOW MOVING COLD
FRONT AND NEAR THE WEAK SFC WAVE. AS SUCH...HAVE KEPT THE VCTS
DESCRIPTORS AT THE SOUTHERN TAF SITES OF KCVG/KLUK.
OTHERWISE...ALL TAF SITES WILL HAVE THE THREAT FOR MVFR
CONDITIONS. IT SHOULD BE NOTED THAT WITH THE MOIST AIRMASS...WELL
DEVELOPED SHOWERS AND ESPECIALLY ANY THUNDERSTORMS...WILL BE
CAPABLE OF LOWER VISIBILITIES IN THE IFR/LIFR CATEGORY...SO
AVIATORS SHOULD BE AWARE OF THIS POTENTIAL.
FOR TONIGHT...THE FRONTAL BOUNDARY WILL CONTINUE ON ITS WAY TO OUR
SOUTHEAST AS THE WEAK WAVE OF LOW PRESSURE BEGINS TO TRANSFER AND
DEEPEN OVER THE MID ATLANTIC REGION. PRECIPITATION THREAT SHOULD
BE EXITING AWAY FROM THE TAF SITES BETWEEN 00Z AND 09Z. WILL
FORECAST VFR CEILINGS/VISIBILITIES OVERNIGHT FOR THE NORTHERN TAF
SITES. IT APPEARS THAT KILN...KCVG...AND KLUK MAY DROP INTO
PREDOMINATE MVFR CEILINGS LATE (WHERE IT MAY RAIN THE MOST TODAY)
WHERE LOW LEVELS WILL SATURATE THE BEST OVERNIGHT.
OUTLOOK...MVFR CEILINGS POSSIBLE THURSDAY MORNING. THUNDERSTORMS
POSSIBLE FRIDAY INTO FRIDAY EVENING. MVFR CEILINGS POSSIBLE AGAIN
FRIDAY NIGHT INTO SATURDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...CONIGLIO
AVIATION...HICKMAN
AREA FORECAST DISCUSSION...UPDATED
NWS NASHVILLE TN
ISSUED BY NATIONAL WEATHER SERVICE JACKSON MS
1020 AM CDT WED SEP 9 2015
.DISCUSSION...VISIBLE SATELLITE IMAGERY THIS MORNING SHOWED A DECK
OF MOSTLY MID/HIGH CLOUDS STREAMING ACROSS SERN PORTIONS OF THE
FORECAST AREA, WITH SUBSTANTIAL BREAKS ACROSS THE REMAINDER OF THE
CWA. AS A RESULT, 15Z TEMPS RANGED FROM THE LOW-MID 80S IN AREAS
SEEING MORE SUNSHINE TO MID-UPPER 70S OVER MUCH OF THE CUMBERLAND
PLATEAU. ISOLATED SHOWERS WERE ONGOING NORTHEAST OF THE METRO AREA
FROM PORTLAND TO AROUND CARTHAGE, HOWEVER MOST AREAS REMAIN DRY AT
THIS POINT.
HEADING THROUGH THE REMAINDER OF THE DAY, THE PRESENCE OF DEEP
LAYER MOISTURE (1.82 IN PW NOTED ON 12Z OHX SOUNDING), DEVELOPING
WEAK TO MODERATE INSTABILITY, AND AN APPROACHING COLD FRONT WILL
PROVIDE INCREASING CONVECTIVE COVERAGE ACROSS THE REGION. THOUGH
RELATIVELY WEAK DEEP LAYER SHEAR AND UNIMPRESSIVE LAPSE RATES WILL
LIMIT THE THREAT OF STRONG STORMS, THUNDERSTORMS WILL BE
POSSIBLE.
SOME MINOR TWEAKS WERE MADE TO THE FORECAST TO INDICATE GREATER
POPS THIS AFTERNOON THAN THIS MORNING. OTHERWISE, THE INHERITED
FORECAST WAS ON TRACK AND NO OTHER ADJUSTMENTS WERE MADE.
DL/JAN
&&
.PREV DISCUSSION... /ISSUED 304 AM CDT WED SEP 9 2015/
SURFACE OBSERVATIONS THIS MORNING SHOW TEMPERATURES AND DEWPOINTS
IN THE 66-73 DEGREE RANGE WHICH IS SEVERAL DEGREES HIGHER THAN
YESTERDAY AT THIS TIME. CLOUD COVER IS ALSO INCREASING EARLY THIS
MORNING AS DEEPER MOISTURE...CHARACTERIZED BY PWATS AROUND 1.85
INCHES PER 00Z RAOBS AT BHM AND ATL...CONTINUES TO ADVECT
NORTHWESTWARD INTO THE MID STATE. IN FACT...LATEST RADAR IMAGERY
SHOWS LIGHT SHOWERS ALREADY DEVELOPING ACROSS NORTH ALABAMA AND
SOUTHERN TENNESSEE ON THE LEADING EDGE OF THIS DEEPER MOISTURE.
LATEST HRRR MODEL GUIDANCE EXPANDS THIS ACTIVITY THROUGHOUT THE
CWA LATER THIS MORNING INTO THE AFTERNOON...WHILE SHOWERS/STORMS
CURRENTLY APPROACHING THE MISSISSIPPI RIVER ALSO SPREAD INTO THE
AREA AS A UPPER TROUGH AXIS SHIFTS EASTWARD ACROSS THE TENNESSEE
VALLEY. THUS WILL CONTINUE LIKELY POPS FOR ALL ZONES...WITH CLOUD
COVER AND PRECIPITATION KEEPING HIGHS DOWN IN THE 80S TODAY.
SHOWERS AND STORMS WILL CONTINUE INTO TONIGHT AS H5 TROUGH AXIS
CONTINUES TO THE EAST...WITH ACTIVITY GRADUALLY SHIFTING
SOUTHEAST OUT OF THE CWA FROM THURSDAY INTO THURSDAY NIGHT AS A
WEAK COLD FRONT PUSHES SOUTHEASTWARD. A FEW SHOWERS AND MAYBE A
THUNDERSTORM APPEAR POSSIBLE ON FRIDAY...BUT A BETTER CHANCE WILL
ARRIVE FRIDAY NIGHT INTO SATURDAY AS THE FIRST STRONG COLD FRONT
OF METEOROLOGICAL FALL ARRIVES. 00Z GFS/ECMWF CONTINUE TO TREND
STRONGER WITH THE UPPER TROUGH THAT WILL FORCE THIS FRONT THROUGH
THE AREA...SO HAVE NUDGED POPS UP A TAD FRIDAY NIGHT INTO
SATURDAY. THE FIRST TASTE OF FALL IS THEN EXPECTED FOR THE REST OF
THE WEEKEND...WITH GFS FINALLY CATCHING ON TO THE ECMWF IN SHOWING
DRY WEATHER WITH SIGNIFICANTLY COOLER TEMPERATURES SOME 10 TO 15
DEGREES BELOW NORMAL FOR THIS TIME OF YEAR. BASED ON THE LATEST
LOCAL MODEL BLEND...WHICH HAS BEEN PERFORMING QUITE WELL OVER THE
PAST MONTH...HIGHS IN THE UPPER 60S AND 70S WITH LOWS IN THE UPPER
40S AND 50S ARE EXPECTED FOR SEVERAL DAYS FROM SUNDAY THROUGH AT
LEAST TUESDAY. AFTER THAT TIME...MODELS DIFFER ON WHETHER A STRONG
COASTAL TROUGH OR POSSIBLE TROPICAL CYCLONE DEVELOPS IN THE
WESTERN GULF OF MEXICO...BUT IF THIS OCCURS MOISTURE FROM THIS
SYSTEM COULD SPREAD NORTHWARD INTO THE AREA LATER NEXT WEEK.
SHAMBURGER
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 86 70 83 66 / 60 60 50 20
CLARKSVILLE 85 68 82 63 / 60 60 30 10
CROSSVILLE 80 66 77 63 / 70 60 60 40
COLUMBIA 86 68 81 64 / 60 60 60 20
LAWRENCEBURG 86 68 82 65 / 60 60 60 20
WAVERLY 85 68 83 64 / 60 60 40 20
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1029 AM CDT WED SEP 9 2015
.UPDATE...
MORNING FORECAST UPDATE...
&&
.DISCUSSION...
LATEST RADAR TRENDS SHOW SHOWER ACTIVITY LEFT OVER FROM A MORNING
MCS OVER N TX. MCS HAS FOR THE MOST PART JUST FALLEN APART WITH
OUTFLOW PUSHING SOUTH IN THE AREA. MAIN QUESTION WILL BE HOW MUCH
RE-DEVELOPMENT OF CONVECTION OCCURS ALONG THE OUTFLOW. UPPER LEVEL
ANALYSIS HAS UPPER RIDGE OVER THE S ROCKIES WITH NW/N FLOW ALOFT
OVER SE TX THAT WRAPS AROUND AN UPPER LOW OVER THE N GULF. LOWER
500MB HEIGHTS AND PRECIP WATER VALUES AROUND 1.8-2 INCHES SUGGEST
ISO TO SCT SHRA/TSRA ACTIVITY AS TEMPS WARM TOWARDS 90F MARK.
RADAR ALREADY SHOWS SCT ACTIVITY OFF THE COAST AND JUST INLAND.
UPDATED RAIN CHANCES TO PRETTY MUCH 40 PRECENT AREAWIDE TO ACCOUNT
FOR SCT SHRA/TSRA ACTIVITY. THERE EVEN MAY BE AN ISO STRONG STORM
SINCE CRP/LCH SOUNDINGS SHOW AROUND 2000 J/KG OF CAPE THIS
MORNING. THINK THE MAIN THREATS WILL BE BRIEF HEAVY RAINFALL AND
GUSTY WINDS WITH FREEZING LEVELS QUITE HIGH. CLOUD COVER MAY KEEP
TEMPS IN THE 80S BUT THERE COULD BE ENOUGH BREAKS TO REACH LOW
90S. MAIN CHANGES TO THE FORECAST WERE TO UPDATE POP/WX/T/TD
FORECAST BASED ON CURRENT TRENDS.
39
&&
.PREV DISCUSSION... /ISSUED /
DISCUSSION...
SEE 12Z AVIATION DISCUSSION.
AVIATION...
PRECIP OVER N TX CONTINUES TO SAG SOUTH AND IF THE LINE HOLDS
TOGETHER...IT SHOULD ARRIVE AT NORTHERN TAF SITES AROUND 15Z.
SHORT TERM GUIDANCE SUGGESTS THAT THE AREA WILL WEAKEN AND IR
IMAGERY SHOWS SOME SLIGHT WARMING OF THE CLOUD TOPS. KGRK VWP
STILL SHOWING 30 KTS OF INFLOW INTO THE LINE WHICH SHOULD HELP
SUSTAIN THE LINE. PW VALUES WILL EXCEED 2.00 INCHES OVER MUCH OF
THEN AREA TODAY SO SCT SHRA/ISO TSRA WILL BE POSSIBLE AT ALL TAF
SITES TODAY. TIMING IS THE TRICKY PART. TOOK A BLEND OF THE NAM...
GFS AND THE ECMWF WITH BEST RAIN CHANCES AT THE HOUSTON TERMINALS
BETWEEN 18-03Z. NCEP 4 KM WRF IS VERY AGGRESSIVE WITH PRECIP
BETWEEN 09-12Z THURSDAY OVER THE SOUTHERN TAF SITES. NOT SURE IF
IT IS ON TO SOMETHING BUT ADDED VCSH FOR KSGR...KHOU...KLBX AND
KGLS FOR EARLY THURSDAY MORNING. 43
PREV DISCUSSION... /ISSUED /
DISCUSSION...
REGIONAL RADAR MOSAIC EARLY THIS MORNING SHOWED A COMPLEX OF
THUNDERSTORMS LOCATED ALONG THE INTERSTATE 20 CORRIDOR PUSHING
SOUTH. EARLY MORNING WATER VAPOR IMAGERY SHOWED THIS COMPLEX WAS
AIDED BY A SHORTWAVE TROUGH MOVING ACROSS NORTH TEXAS... WITH 06Z
SURFACE ANALYSIS PLACING A COLD FRONT BEHIND THESE THUNDERSTORMS
FROM WEST TEXAS INTO CENTRAL OKLAHOMA. EVENING UPPER AIR ANALYSIS
SHOWED A BROAD UPPER TROUGH SWINGING ACROSS THE SOUTHERN/CENTRAL
PLAINS AND THIS TROUGH WILL HELP PUSH THE COLD FRONT CLOSER TO THE
REGION THROUGHOUT TODAY AND TOMORROW.
FOR TODAY... THE FT. HOOD VAD WIND PROFILER SHOWS 25 TO 30 KNOTS
OF SOUTHERLY INFLOW FEEDING INTO THE THUNDERSTORM COMPLEX OVER
NORTH TEXAS EARLY THIS MORNING. THIS SHOULD HELP THESE
THUNDERSTORMS MAINTAIN THEMSELVES THROUGH THE REMAINDER OF THE
EARLY MORNING HOURS. AS LOW LEVEL INFLOW VEERS AND WEAKENS LATER
LATER THIS MORNING HOWEVER... UNCERTAINTY BEGINS TO INCREASE ON
HOW FAR SOUTH THIS COMPLEX WILL MAKE IT. SOME HIGH RESOLUTION
GUIDANCE SOLUTIONS /NOTABLY THE HRRR AND TEXAS TECH WRF/ SHOWS
OUTFLOW FROM THIS COMPLEX REACHING THE BRAZOS VALLEY LATE
MORNING/EARLY AFTERNOON. GIVEN RADAR AND SATELLITE TRENDS... THINK
AREAS NORTH OF A BRENHAM TO LIVINGSTON LINE APPEAR TO BE THE MOST
LIKELY TO SEE RAIN FROM THIS COMPLEX OR ANY ASSOCIATED OUTFLOW AND
HIGHLIGHTING THE HIGHEST POPS FOR THE DAY IN THESE AREAS. EVEN IF
THE STORMS DISSIPATE BEFORE THE OUTFLOW REACHES THE AREA...
DIABATIC HEATING MAY CONTRIBUTE TO ADDITIONAL DEVELOPMENT ALONG IT
LATER THIS AFTERNOON.
FARTHER SOUTH... CONVECTIVE TEMPERATURES NEAR 90 TODAY WILL ALSO
SUPPORT ISOLATED TO SCATTERED THUNDERSTORM DEVELOPMENT ACROSS THE
REMAINDER OF THE REGION... ESPECIALLY AS A SEA BREEZE MOVES
FARTHER INLAND. THE UPPER LOW CHURNING OVER THE NORTHERN GULF
EARLY THIS MORNING IS EXPECTED TO SHEAR OUT TODAY... DECREASING
THE SUBSIDENCE THAT HAS LIMITED MORE ROBUST COVERAGE OVER THE PAST
FEW DAYS. IF THE OUTFLOW IS ABLE TO MAKE IT FARTHER SOUTH TODAY
THAN ORIGINALLY THOUGHT... POPS ALSO WILL NEED TO BE INCREASED
FARTHER SOUTH TODAY. ADDITIONALLY... FORECAST SOUNDINGS FOR
HOUSTON THIS AFTERNOON HAVE A DISTINCT INVERTED-V SIGNATURE AND
THIS WILL SUPPORT AT LEAST AN ISOLATED GUSTY WIND THREAT FROM ANY
THUNDERSTORM THAT DEVELOPS.
THE COLD FRONT IS EXPECTED TO MAKE SLOW PROGRESS ACROSS NORTH
TEXAS TODAY... AND WITH SOME UNCERTAINTY ON WHERE OUTFLOW FROM
TODAY/S THUNDERSTORMS WILL END UP KEEPING POPS HIGHEST TONIGHT
ALONG AND NORTH OF A BRENHAM TO CLEVELAND LINE. AS PRECIPITABLE
WATER VALUES RISE TO NEAR 2 INCHES LATER TODAY AND INTO TOMORROW...
LOCALLY HEAVY RAIN WILL REMAIN POSSIBLE. OTHERWISE... EXPECT
HIGHS IN THE UPPER 80S TO LOW 90S TODAY AND LOWS IN THE 70S TO
NEAR 80 TONIGHT.
THE GREAT PLAINS UPPER TROUGH WILL CONTINUE TO SWING EAST TOWARDS
THE GREAT LAKES ON THURSDAY... WITH ITS AXIS EXTENDING OVER THE
REGION. THE COLD FRONT WILL MAKE MORE PROGRESS INTO/ STALL
SOMEWHERE ACROSS CENTRAL TEXAS ON THURSDAY AND THIS WITH ADDED
LIFT FROM A 50-60 KNOT UPPER LEVEL JET STREAK APPROACHING FROM
WEST TEXAS WILL KEEP SCATTERED TO NUMEROUS THUNDERSTORMS IN THE
FORECAST ON THURSDAY AND FRIDAY. HIGHS TO END THE WEEK WILL BE
NEAR NORMAL IN THE MID TO UPPER 80S.
HEADING INTO THE WEEKEND... A STRONG SHORTWAVE TROUGH ROTATING
AROUND THE BASE OF THE BROAD UPPER TROUGH FRIDAY/SATURDAY WILL
SEND A SECONDARY... STRONGER FRONT INTO THE REGION. THIS FRONT
LOOKS TO PUSH THROUGH THE REGION SOMETIME ON SATURDAY WITH MUCH
DRIER AIR FILTERING INTO THE AREA BEHIND IT. PRECIPITABLE WATER
VALUES WILL FALL THROUGHOUT THE DAY ON SATURDAY... BOTTOMING OUT
UNDER ONE INCH ON SUNDAY. THIS WILL ALLOW RAIN CHANCES TO TAPER
OFF FROM NORTH TO SOUTH DURING THE DAY ON SATURDAY AND PROVIDE
WHAT APPEARS TO BE A VERY PLEASANT SUNDAY IN THE MAKING. DRIER AIR
WILL ALLOW FOR OVERNIGHT LOW TEMPERATURES TO POSSIBLY FALL INTO
THE 60S SUNDAY... WITH HIGHS IN THE LOW TO MID 80S.
MEDIUM RANGE GUIDANCE CONTINUES TO SHOW THE DEVELOPMENT OF A
COASTAL TROUGH/SURFACE LOW OFF MEXICO/DEEP SOUTH TEXAS HEADING
INTO THE BEGINNING OF NEXT WEEK. WHILE STILL OFFERING SOMEWHAT
DIFFERENT SOLUTIONS... THE GFS AND THE EUROPEAN BOTH ADVERTISE A
GOOD SLUG OF TROPICAL MOISTURE ASSOCIATED WITH THIS FEATURE MAKING
ITS WAY BACK INTO THE REGION /GFS PWATS INCREASE FROM LESS THAN
ONE INCH MONDAY TO NEARLY 2 INCHES ON TUESDAY/ HEADING INTO THE
MIDDLE OF NEXT WEEK. SHOWER AND THUNDERSTORM CHANCES WILL RETURN
AS THIS SYSTEM EJECTS NORTHWARD TOWARDS THE TEXAS COAST... AND
WILL NEED TO CONTINUE TO MONITOR FOR THE POTENTIAL OF HEAVY RAIN.
HUFFMAN
MARINE...
LIGHT TO MODERATE ONSHORE FLOW WILL PERSIST THROUGH FRIDAY. PERIODS
OF UNSETTLED WEATHER CAN BE EXPECTED...ESPECIALLY THURSDAY THROUGH
SATURDAY...AS UPPER LEVEL DISTURBANCES INTERACT WITH DEEPER MOISTURE
IN THE AREA. WINDS/SEAS WILL BE HIGHER IN AND NEAR STORMS. A WEAK
FRONTAL BOUNDARY WILL PUSH INTO THE WATERS LATE FRIDAY NIGHT OR
SATURDAY MORNING WITH NORTHEAST WINDS IN ITS WAKE. A WEAK TROUGH OF
LOW PRESSURE WILL DEVELOP NEAR THE LOWER TEXAS COAST EARLY NEXT WEEK
AND THIS FEATURE WILL BRING PERIODS OF SHRA/TSRA AND A PROLONGED
PERIOD OF E-SE WINDS TO THE UPPER TEXAS COASTAL WATERS. 43
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 91 75 89 74 89 / 40 50 60 30 40
HOUSTON (IAH) 91 75 89 74 87 / 40 30 60 40 50
GALVESTON (GLS) 88 81 89 79 85 / 40 30 60 50 60
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...39
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
652 AM CDT WED SEP 9 2015
.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
&&
.AVIATION...LIGHT SOUTHEAST WINDS WITH A FEW PASSING CLOUDS
PREVAIL OVER DEEP SOUTH TEXAS THIS MORNING. VFR CONDITIONS
EXPECTED THROUGH THE NEXT 24 HOURS...EXCEPT A BRIEF PERIOD OF MVFR
CONDITIONS POSSIBLE IN ANY CONVECTION. ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS THE EASTERN PORTIONS
OF THE CWA ALONG AND AHEAD OF THE SEABREEZE FRONT MOVING INLAND
THIS AFTERNOON. LIGHT SOUTHEAST WINDS WILL BECOME MODERATE LATER
THIS MORNING WITH GUSTS AROUND 20 KNOTS IN THE AFTERNOON. WINDS
WILL GRADUALLY WEAKEN THIS EVENING AND OVERNIGHT.
&&
.PREV DISCUSSION... /ISSUED 434 AM CDT WED SEP 9 2015/
SHORT TERM /NOW THROUGH THURSDAY/...LATEST WATER VAPOR SATELLITE
IMAGERY SHOWS A 500MB RIDGE CENTERED OVER WEST TEXAS INTO NORTHERN
MEXICO AND A 500MB LOW OVER THE WESTERN GULF OF MEXICO. BROWNSVILLE
RADAR SHOWS VERY ISOLATED ACTIVITY ACROSS THE LOWER TEXAS GULF
WATERS THIS MORNING. THE LATEST HRRR SUGGESTS CONVECTION WILL
INCREASE ACROSS THE GULF WATERS LATER THIS MORNING. BRO SOUNDING
FROM TUESDAY EVENING INDICATES PRECIPITABLE WATER VALUES OF 2.02
INCHES. MOSTLY CLEAR SKIES AND LIGHT WINDS PREVAIL ACROSS DEEP SOUTH
TEXAS EARLY THIS MORNING. NOTE...THE SURFACE OBSERVATION FROM
EDINBURG IS NOT REPRESENTATIVE TO CURRENT WEATHER CONDITIONS.
THE COMBINATION OF THE 500MB LOW ACROSS THE WESTERN GULF OF MEXICO
AND A FRONT MOVING SOUTH OVER CENTRAL TEXAS WILL ALLOW LOW TO MID
LEVEL MOISTURE TO INCREASE ACROSS DEEP SOUTH TEXAS THROUGH THE
FORECAST PERIOD. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
WILL DEVELOP ACROSS THE EASTERN PORTIONS OF THE CWA ALONG AND AHEAD
OF THE SEABREEZE FRONT MOVING INLAND THIS AFTERNOON. THE LATEST
HRRR/GFS AND ECMWF SUGGEST AN ACTIVE SEA BREEZE TODAY WHILE THE MET
REMAINS GENERALLY DRY. WILL LEAN TOWARDS THE WETTER MAV/ECMWF MOS
POPS FOR TODAY.
DEEPER MOISTURE SHOULD SUPPORT MORE ACTIVITY ACROSS THE AREA ON
THURSDAY...ESPECIALLY ACROSS THE COASTAL WATERS AND THE RANCHLANDS.
WILL BLEND TOWARDS THE WETTER NAM/ECMWF FOR POPS AREA WIDE FOR
THURSDAY.
ANY OF THE HEAVIER OR SLOWER-MOVING SHOWERS AND THUNDERSTORMS TODAY
AND THURSDAY WILL HAVE THE POTENTIAL TO PRODUCE LOCALLY HEAVY
RAINFALL WITH NUISANCE FLOODING ON ROADS AND IN LOW-LYING
AREAS...ESPECIALLY THOSE WITH A HISTORY OF FLOODING.
HIGH TEMPERATURES TODAY WILL RANGE FROM THE LOWER 90S NEAR THE COAST
TO AROUND 100 ACROSS THE UPPER VALLEY. HIGH TEMPERATURES WILL BE A
FEW DEGREES LOWER ON THURSDAY DUE TO THE INCREASE IN CLOUDS AND RAIN
CHANCES. LOW TEMPERATURES TONIGHT WILL GENERALLY BE IN THE UPPER 70S
TO AROUND 80.
LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...RATHER BUSY LONG
TERM PORTION OF THE FORECAST ANTICIPATED. DEEP TROPICAL MOISTURE
(PRECIPITABLE WATER VALUES IN EXCESS OF 2 INCHES) WILL COMBINE
WITH THE FRIDAY NIGHT PASSAGE OF A WEAK COLD FRONT...AND THE
SUBSEQUENT DEVELOPMENT AND PERSISTENCE OF AN INVERTED SURFACE
TROUGH OF LOW PRESSURE ALONG THE LOWER TEXAS COAST AFTERWARDS.
WITH PERSISTENT 500 MB TROUGHINESS ALONG THE TEXAS COASTLINE IN
ASSOCIATION WITH A CLOSED 500 MB LOW PRESSURE SYSTEM OVER THE
GREAT LAKES REGION...DEEP SOUTH TEXAS AND THE RIO GRANDE VALLEY
CAN EXPECT SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS FOR
MUCH OF THE FORECAST PERIOD...WITH THE HIGHEST RAIN CHANCES FROM
FRIDAY THROUGH SATURDAY...WHEN LOCALLY HEAVY RAINFALL HAS ALSO
BEEN INCLUDED IN THE FORECAST. THE MOST INTERESTING ASPECT OF THE
LONG TERM FORECAST PERIOD IS THE GFS` INDICATION THAT A WEAK
CLOSED AREA OF LOW PRESSURE WILL FORM OVER THE WESTERN GULF OF
MEXICO AND MOVE INLAND OVER THE BRO CWFA TOWARDS THE END OF THE
FORECAST PERIOD. ANY CLOSED AREA OF LOW PRESSURE...SHOULD IT
FORM...WOULD HAVE THE ABILITY TO RADICALLY CHANGE PRECIPITATION
AND WIND VALUES ON MONDAY AND TUESDAY...AND THIS WILL NEED TO BE
MONITORED BY SUCCESSIVE SHIFTS THROUGH THE NEXT FEW DAYS.
MARINE...NOW THROUGH THURSDAY...BUOY DATA AND OBSERVATION PLATFORMS
ALONG THE LOWER TEXAS COAST THIS MORNING INDICATE SOUTH WINDS BETWEEN
8 TO 13 KNOTS WITH SEA HEIGHTS NEAR 3 FEET ON THE GULF WATERS. A
WEAK PRESSURE GRADIENT OVER THE WESTERN GULF OF MEXICO WILL
MAINTAIN LIGHT TO MODERATE SOUTHEAST TO SOUTH WINDS AND LOW TO
MODERATE SEAS. HOWEVER...SMALL CRAFT WILL NEED TO EXERCISE CAUTION
ON THE LAGUNA MADRE THIS AFTERNOON DUE TO A SLIGHTLY STRONGER
WINDS.
THURSDAY NIGHT THROUGH TUESDAY...GENERALLY LIGHT TO MODERATE WINDS
AND LOW TO MODERATE SEAS ARE EXPECTED THROUGH THE PERIOD AS WEAK
LOW PRESSURE PERSISTS OVER THE WESTERN GULF OF MEXICO AND A COLD
FRONT INTRUDES INTO THE LOWER TEXAS COASTAL WATERS. WEAK CLOSED
LOW PRESSURE MAY DEVELOP ALONG THE LOWER TEXAS COAST TOWARDS THE
END OF THE FORECAST PERIOD PER ONE WEATHER FORECAST MODEL...BUT
THE STRONGER WINDS AND HIGHER SEAS INDICATED IN ASSOCIATION WITH
THE LOW PRESSURE DEVELOPMENT HAVE NOT BEEN INCLUDED IN THE
FORECAST AT THIS TIME.
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
63
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
624 AM CDT WED SEP 9 2015
.DISCUSSION...
SEE 12Z AVIATION DISCUSSION.
&&
.AVIATION...
PRECIP OVER N TX CONTINUES TO SAG SOUTH AND IF THE LINE HOLDS
TOGETHER...IT SHOULD ARRIVE AT NORTHERN TAF SITES AROUND 15Z.
SHORT TERM GUIDANCE SUGGESTS THAT THE AREA WILL WEAKEN AND IR
IMAGERY SHOWS SOME SLIGHT WARMING OF THE CLOUD TOPS. KGRK VWP
STILL SHOWING 30 KTS OF INFLOW INTO THE LINE WHICH SHOULD HELP
SUSTAIN THE LINE. PW VALUES WILL EXCEED 2.00 INCHES OVER MUCH OF
THEN AREA TODAY SO SCT SHRA/ISO TSRA WILL BE POSSIBLE AT ALL TAF
SITES TODAY. TIMING IS THE TRICKY PART. TOOK A BLEND OF THE NAM...
GFS AND THE ECMWF WITH BEST RAIN CHANCES AT THE HOUSTON TERMINALS
BETWEEN 18-03Z. NCEP 4 KM WRF IS VERY AGGRESSIVE WITH PRECIP
BETWEEN 09-12Z THURSDAY OVER THE SOUTHERN TAF SITES. NOT SURE IF
IT IS ON TO SOMETHING BUT ADDED VCSH FOR KSGR...KHOU...KLBX AND
KGLS FOR EARLY THURSDAY MORNING. 43
&&
.PREV DISCUSSION... /ISSUED /
DISCUSSION...
REGIONAL RADAR MOSAIC EARLY THIS MORNING SHOWED A COMPLEX OF
THUNDERSTORMS LOCATED ALONG THE INTERSTATE 20 CORRIDOR PUSHING
SOUTH. EARLY MORNING WATER VAPOR IMAGERY SHOWED THIS COMPLEX WAS
AIDED BY A SHORTWAVE TROUGH MOVING ACROSS NORTH TEXAS... WITH 06Z
SURFACE ANALYSIS PLACING A COLD FRONT BEHIND THESE THUNDERSTORMS
FROM WEST TEXAS INTO CENTRAL OKLAHOMA. EVENING UPPER AIR ANALYSIS
SHOWED A BROAD UPPER TROUGH SWINGING ACROSS THE SOUTHERN/CENTRAL
PLAINS AND THIS TROUGH WILL HELP PUSH THE COLD FRONT CLOSER TO THE
REGION THROUGHOUT TODAY AND TOMORROW.
FOR TODAY... THE FT. HOOD VAD WIND PROFILER SHOWS 25 TO 30 KNOTS
OF SOUTHERLY INFLOW FEEDING INTO THE THUNDERSTORM COMPLEX OVER
NORTH TEXAS EARLY THIS MORNING. THIS SHOULD HELP THESE
THUNDERSTORMS MAINTAIN THEMSELVES THROUGH THE REMAINDER OF THE
EARLY MORNING HOURS. AS LOW LEVEL INFLOW VEERS AND WEAKENS LATER
LATER THIS MORNING HOWEVER... UNCERTAINTY BEGINS TO INCREASE ON
HOW FAR SOUTH THIS COMPLEX WILL MAKE IT. SOME HIGH RESOLUTION
GUIDANCE SOLUTIONS /NOTABLY THE HRRR AND TEXAS TECH WRF/ SHOWS
OUTFLOW FROM THIS COMPLEX REACHING THE BRAZOS VALLEY LATE
MORNING/EARLY AFTERNOON. GIVEN RADAR AND SATELLITE TRENDS... THINK
AREAS NORTH OF A BRENHAM TO LIVINGSTON LINE APPEAR TO BE THE MOST
LIKELY TO SEE RAIN FROM THIS COMPLEX OR ANY ASSOCIATED OUTFLOW AND
HIGHLIGHTING THE HIGHEST POPS FOR THE DAY IN THESE AREAS. EVEN IF
THE STORMS DISSIPATE BEFORE THE OUTFLOW REACHES THE AREA...
DIABATIC HEATING MAY CONTRIBUTE TO ADDITIONAL DEVELOPMENT ALONG IT
LATER THIS AFTERNOON.
FARTHER SOUTH... CONVECTIVE TEMPERATURES NEAR 90 TODAY WILL ALSO
SUPPORT ISOLATED TO SCATTERED THUNDERSTORM DEVELOPMENT ACROSS THE
REMAINDER OF THE REGION... ESPECIALLY AS A SEA BREEZE MOVES
FARTHER INLAND. THE UPPER LOW CHURNING OVER THE NORTHERN GULF
EARLY THIS MORNING IS EXPECTED TO SHEAR OUT TODAY... DECREASING
THE SUBSIDENCE THAT HAS LIMITED MORE ROBUST COVERAGE OVER THE PAST
FEW DAYS. IF THE OUTFLOW IS ABLE TO MAKE IT FARTHER SOUTH TODAY
THAN ORIGINALLY THOUGHT... POPS ALSO WILL NEED TO BE INCREASED
FARTHER SOUTH TODAY. ADDITIONALLY... FORECAST SOUNDINGS FOR
HOUSTON THIS AFTERNOON HAVE A DISTINCT INVERTED-V SIGNATURE AND
THIS WILL SUPPORT AT LEAST AN ISOLATED GUSTY WIND THREAT FROM ANY
THUNDERSTORM THAT DEVELOPS.
THE COLD FRONT IS EXPECTED TO MAKE SLOW PROGRESS ACROSS NORTH
TEXAS TODAY... AND WITH SOME UNCERTAINTY ON WHERE OUTFLOW FROM
TODAY/S THUNDERSTORMS WILL END UP KEEPING POPS HIGHEST TONIGHT
ALONG AND NORTH OF A BRENHAM TO CLEVELAND LINE. AS PRECIPITABLE
WATER VALUES RISE TO NEAR 2 INCHES LATER TODAY AND INTO TOMORROW...
LOCALLY HEAVY RAIN WILL REMAIN POSSIBLE. OTHERWISE... EXPECT
HIGHS IN THE UPPER 80S TO LOW 90S TODAY AND LOWS IN THE 70S TO
NEAR 80 TONIGHT.
THE GREAT PLAINS UPPER TROUGH WILL CONTINUE TO SWING EAST TOWARDS
THE GREAT LAKES ON THURSDAY... WITH ITS AXIS EXTENDING OVER THE
REGION. THE COLD FRONT WILL MAKE MORE PROGRESS INTO/ STALL
SOMEWHERE ACROSS CENTRAL TEXAS ON THURSDAY AND THIS WITH ADDED
LIFT FROM A 50-60 KNOT UPPER LEVEL JET STREAK APPROACHING FROM
WEST TEXAS WILL KEEP SCATTERED TO NUMEROUS THUNDERSTORMS IN THE
FORECAST ON THURSDAY AND FRIDAY. HIGHS TO END THE WEEK WILL BE
NEAR NORMAL IN THE MID TO UPPER 80S.
HEADING INTO THE WEEKEND... A STRONG SHORTWAVE TROUGH ROTATING
AROUND THE BASE OF THE BROAD UPPER TROUGH FRIDAY/SATURDAY WILL
SEND A SECONDARY... STRONGER FRONT INTO THE REGION. THIS FRONT
LOOKS TO PUSH THROUGH THE REGION SOMETIME ON SATURDAY WITH MUCH
DRIER AIR FILTERING INTO THE AREA BEHIND IT. PRECIPITABLE WATER
VALUES WILL FALL THROUGHOUT THE DAY ON SATURDAY... BOTTOMING OUT
UNDER ONE INCH ON SUNDAY. THIS WILL ALLOW RAIN CHANCES TO TAPER
OFF FROM NORTH TO SOUTH DURING THE DAY ON SATURDAY AND PROVIDE
WHAT APPEARS TO BE A VERY PLEASANT SUNDAY IN THE MAKING. DRIER AIR
WILL ALLOW FOR OVERNIGHT LOW TEMPERATURES TO POSSIBLY FALL INTO
THE 60S SUNDAY... WITH HIGHS IN THE LOW TO MID 80S.
MEDIUM RANGE GUIDANCE CONTINUES TO SHOW THE DEVELOPMENT OF A
COASTAL TROUGH/SURFACE LOW OFF MEXICO/DEEP SOUTH TEXAS HEADING
INTO THE BEGINNING OF NEXT WEEK. WHILE STILL OFFERING SOMEWHAT
DIFFERENT SOLUTIONS... THE GFS AND THE EUROPEAN BOTH ADVERTISE A
GOOD SLUG OF TROPICAL MOISTURE ASSOCIATED WITH THIS FEATURE MAKING
ITS WAY BACK INTO THE REGION /GFS PWATS INCREASE FROM LESS THAN
ONE INCH MONDAY TO NEARLY 2 INCHES ON TUESDAY/ HEADING INTO THE
MIDDLE OF NEXT WEEK. SHOWER AND THUNDERSTORM CHANCES WILL RETURN
AS THIS SYSTEM EJECTS NORTHWARD TOWARDS THE TEXAS COAST... AND
WILL NEED TO CONTINUE TO MONITOR FOR THE POTENTIAL OF HEAVY RAIN.
HUFFMAN
MARINE...
LIGHT TO MODERATE ONSHORE FLOW WILL PERSIST THROUGH FRIDAY. PERIODS
OF UNSETTLED WEATHER CAN BE EXPECTED...ESPECIALLY THURSDAY THROUGH
SATURDAY...AS UPPER LEVEL DISTURBANCES INTERACT WITH DEEPER MOISTURE
IN THE AREA. WINDS/SEAS WILL BE HIGHER IN AND NEAR STORMS. A WEAK
FRONTAL BOUNDARY WILL PUSH INTO THE WATERS LATE FRIDAY NIGHT OR
SATURDAY MORNING WITH NORTHEAST WINDS IN ITS WAKE. A WEAK TROUGH OF
LOW PRESSURE WILL DEVELOP NEAR THE LOWER TEXAS COAST EARLY NEXT WEEK
AND THIS FEATURE WILL BRING PERIODS OF SHRA/TSRA AND A PROLONGED
PERIOD OF E-SE WINDS TO THE UPPER TEXAS COASTAL WATERS. 43
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 92 75 89 74 89 / 60 50 60 30 40
HOUSTON (IAH) 91 75 89 74 87 / 40 30 60 40 50
GALVESTON (GLS) 90 81 89 79 85 / 30 30 60 50 60
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...14
AVIATION/MARINE...43
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
154 PM PDT WED SEP 9 2015
.SYNOPSIS...
UPPER-LEVEL HIGH PRESSURE WILL CONTINUE HOT WEATHER THROUGH
THURSDAY...WITH SLOW COOLING FRIDAY INTO EARLY NEXT WEEK. AFTERNOON
AND EARLY EVENING HEAVY THUNDERSTORMS WILL CONTINUE OVER THE INLAND
AREAS THROUGH THURSDAY...LEADING TO AN ENHANCED FLASH FLOOD
THREAT...AS MOISTURE FROM HURRICANE LINDA MOVES OVER THE REGION. THE
AFTERNOON AND EARLY EVENING THUNDERSTORM THREAT CONTINUES FOR THE
MOUNTAINS AND DESERTS THROUGH THE WEEKEND. EVEN COASTAL AREAS MAY
SEE A THUNDERSTORM OR TWO THIS AFTERNOON AND THURSDAY. COOLER AND
DRIER NEXT WEEK AS A TROUGH OF LOW PRESSURE MOVES IN ALONG THE WEST
COAST.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
MORNING SOUNDING CONTINUES TO SHOW A MOIST AND UNSTABLE
ATMOSPHERE...WITH 1.65 INCHES OF PRECIPITABLE WATER AND 780 J/KG OF
MOST UNSTABLE CAPE. CURRENT SPC MESOANALYSIS SHOWS 1000-1500 J/KG OF
SURFACE BASED CAPE. THUS...RADAR SHOWS THAT THUNDERSTORMS ARE
ERUPTING OVER THE MOUNTAINS...HIGH DESERTS AND VALLEYS THIS
AFTERNOON.
THE SOUNDING ALSO SHOWS MORE OF AN EASTERLY COMPONENT TO THE WINDS
IN THE LOW LEVELS. WITH THE WRF SHOWING 700-500 MB WINDS OUT OF THE
EAST OF AROUND 10-15 KT AND THE SURFACE CONVERGENCE BOUNDARY SETTING
UP IN THE VALLEYS...THIS IS RESULTING IN THUNDERSTORMS DRIFTING IN
THE VALLEY AREAS TODAY. IN FACT...THE LATEST HRRR SHOWS THAT THE
SOME SHOWERS OR THUNDERSTORMS COULD DRIFT INTO THE COASTAL AREAS
THIS AFTERNOON...SO HAVE ADDED A SLIGHT CHANCE OF
THUNDERSTORMS/SHOWERS FOR THOSE AREAS WITH THE AFTERNOON FORECAST.
ON THURSDAY...PRECIPITABLE WATER INCREASES TO 2 INCHES ACCORDING TO
THE GFS AND NAM...AS THE CIRCULATION OF LINDA MOVES NORTHWEST TO A
POSITION FAR WEST OF NORTHERN BAJA...RESULTING IN CONTINUED EAST TO
SOUTHEAST FLOW BRINGING THE MOISTURE INTO THE AREA. WRF SHOWS THE
EAST WINDS IN THE 700-500 MB LAYER INCREASING TO 20 KT...WHICH MEANS
THAT STORMS SHOULD BE MOVING QUICKER AND THAT THEY MAY BE ABLE TO
DRIFT INTO COASTAL AREAS AS WELL. ONE POSSIBLE LIMITING FACTOR ON
THURSDAY IS IF THERE IS TOO MUCH CLOUD COVER...WHICH COULD DECREASE
THE AMOUNT OF INSTABILITY. THERE IS STILL A FAIR AMOUNT OF MOISTURE
IN THE REGION ON FRIDAY...WITH PRECIPITABLE WATER ONLY DECREASING TO
1.7-1.8 INCHES UNDER SOUTHEAST FLOW ALOFT...SO THUNDERSTORMS ARE
LIKELY TO DEVELOP AGAIN FRIDAY AFTERNOON AND EARLY EVENING IN THE
MOUNTAINS AND VALLEYS. THE AFTERNOON AND EARLY EVENING THUNDERSTORM
THREAT CONTINUES FOR THE MOUNTAINS AND DESERTS SATURDAY WITH
MOISTURE DIMINISHING A LITTLE...AND THEN THE GFS SHOWS MOISTURE
DECREASING FURTHER ON SUNDAY. FOR DETAILS ON THE FLASH FLOOD
THREAT...PLEASE SEE THE HYDROLOGY SECTION BELOW.
THE HEAT AND MUGGY CONDITIONS IS THE OTHER STORY...AS OVERNIGHT LOWS
WERE ONLY IN THE LOW TO MID 70S. THE LOW OF 77 DEGREES AT LINDBERGH
FIELD WAS ONE DEGREE BELOW THE ALL-TIME HIGHEST MINIMUM TEMPERATURE.
CURRENTLY...THE TEMPERATURES ARE SEVERAL DEGREES ARE HIGHER THAN AT
THIS TIME YESTERDAY. SOME EASTERLY DOWNSLOPE FLOW ASSOCIATED WITH
THE CIRCULATION OF LINDA COULD BRING CONTINUED HOT CONDITIONS TO THE
SAN DIEGO COUNTY COAST AND VALLEYS THURSDAY AS WELL...ALTHOUGH IT
DOES NOT LOOK QUITE AS HOT AS THE MODELS WERE SHOWING YESTERDAY. A
SLOW COOLING TREND LOOKS TO START FRIDAY INTO SATURDAY...WITH MORE
SIGNIFICANT COOLING SUNDAY INTO EARLY NEXT WEEK AS THE RIDGE WEAKENS
AND WE GET A TROUGH ALONG THE WEST COAST. NIGHT AND MORNING MARINE
LAYER CLOUDS COULD RETURN BY SATURDAY NIGHT.
&&
.AVIATION...
092000Z...GENERALLY...NO VIS RESTRICTIONS INTO THURSDAY
WITH OCCASIONAL CLOUDS ABOVE 10000 FEET MSL. BETWEEN 09/20-10/02Z
THIS AFTERNOON...THUNDERSTORMS ARE POSSIBLE IN THE
MOUNTAINS...DESERTS AND VALLEYS WITH BASES 8000 FEET MSL AND TOPS TO
45000 FEET. EXPECT STRONG UPDRAFTS AND DOWNDRAFTS...MAINLY SMALL
HAIL...AND SURFACE GUSTS OVER 35 KT NEAR ANY STORM. IN STORMS LOCAL
VIS REDUCED TO 2SM IN HEAVY RAIN AND/OR BLOWING DUST IN DESERTS.
CONFIDENCE IN THE FORECAST OF A VERY LOW RISK OF LOW CLOUDS FOR KSAN
TONIGHT IS HIGH...WITH EVEN LESS RISK OF LOW CLOUDS AT KONT
OVERNIGHT TONIGHT.
&&
.MARINE...
1255 PM...THERE IS A SLIGHT CHANCE OF A THUNDERSTORM THURSDAY
AFTERNOON AND EVENING NEAR THE COAST. OTHERWISE...NO HAZARDOUS
MARINE WEATHER IS EXPECTED THROUGH SUNDAY.
&&
.BEACHES...
1255 PM...A NEW SOUTH SOUTHEAST SWELL FROM HURRICANE LINDA WILL
ARRIVE THIS AFTERNOON INTO FRIDAY MORNING. THIS SWELL WILL PRODUCE 4-
6 FOOT SURF AT ORANGE COUNTY BEACHES INTO FRIDAY...WITH A FEW HIGHER
SETS. THERE IS A SLIGHT CHANCE OF THUNDERSTORMS AT THE BEACHES
THURSDAY AFTERNOON AND EVENING. THERE IS A BEACH HAZARDS STATEMENT
IN EFFECT FOR ELEVATED SURF AND STRONG RIP CURRENTS THROUGH FRIDAY
MORNING.
&&
.HYDROLOGY...
MODERATE TO HIGH FLASH FLOOD THREAT CONTINUES TODAY FOR THE
MOUNTAINS...DESERTS AND THE VALLEYS...DUE TO THE MOIST AND UNSTABLE
ATMOSPHERE. THUS...THUNDERSTORMS ARE ERUPTING OVER THE INLAND
EMPIRE...HIGH DESERTS AND SAN BERNARDINO COUNT MOUNTAINS. THE WINDS
ALOFT ARE SOMEWHAT WEAK AS WELL...RESULTING IN SOME SLOW MOVING
STORMS WHICH ARE INCREASING THE THREAT OF FLASH FLOODING FURTHER.
RAIN RATES OF 1 TO 2 INCHES PER HOUR WILL BE POSSIBLE UNDERNEATH THE
HEAVIER STORMS. FLASH FLOODING HAS ALREADY OCCURRED IN FOREST FALLS
THIS AFTERNOON. THE FLASH FLOOD WATCH CONTINUES THROUGH THURSDAY FOR
THE MOUNTAINS...DESERTS AND VALLEYS...ALTHOUGH STORMS MAY BE MOVING
QUICKER ON THURSDAY WHICH COULD DIMINISH THE FLASH FLOOD THREAT A
BIT. HOWEVER...TRAINING STORMS COULD BE A CONCERN. THE THREAT LOWERS
FURTHER FRIDAY INTO THE WEEKEND AS MOISTURE SLOWLY DECREASES.
&&
.SKYWARN...
SKYWARN ACTIVATION IS REQUESTED THROUGH EARLY EVENING FOR SAN DIEGO
COUNTY...RIVERSIDE COUNTY...AND SAN BERNARDINO COUNTY.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...FLASH FLOOD WATCH THROUGH THURSDAY EVENING FOR APPLE AND LUCERNE
VALLEYS-COACHELLA VALLEY-RIVERSIDE COUNTY MOUNTAINS-SAN
BERNARDINO COUNTY MOUNTAINS-SAN BERNARDINO AND RIVERSIDE
COUNTY VALLEYS-THE INLAND EMPIRE-SAN DIEGO COUNTY DESERTS-
SAN DIEGO COUNTY MOUNTAINS-SAN DIEGO COUNTY VALLEYS-SAN
GORGONIO PASS NEAR BANNING.
HEAT ADVISORY UNTIL 6 PM PDT THURSDAY FOR ORANGE COUNTY INLAND
AREAS-SAN BERNARDINO AND RIVERSIDE COUNTY VALLEYS-THE
INLAND EMPIRE-SAN DIEGO COUNTY COASTAL AREAS-SAN DIEGO
COUNTY VALLEYS-SANTA ANA MOUNTAINS AND FOOTHILLS.
BEACH HAZARDS STATEMENT THROUGH FRIDAY MORNING FOR ORANGE COUNTY
COASTAL AREAS.
PZ...NONE.
&&
$$
PUBLIC/HYDROLOGY...HARRISON
AVIATION/MARINE/BEACHES...SMALL
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
958 AM PDT WED SEP 9 2015
.SYNOPSIS...
UPPER-LEVEL HIGH PRESSURE WILL CONTINUE HOT WEATHER THROUGH
THURSDAY...WITH SLOW COOLING FRIDAY INTO EARLY NEXT WEEK. AFTERNOON
AND EARLY EVENING HEAVY THUNDERSTORMS WILL CONTINUE OVER THE INLAND
AREAS THROUGH THURSDAY...LEADING TO AN ENHANCED FLASH FLOOD
THREAT...AS MOISTURE FROM HURRICANE LINDA MOVES OVER THE REGION. THE
AFTERNOON AND EARLY EVENING THUNDERSTORM THREAT CONTINUES FOR THE
MOUNTAINS AND DESERTS THROUGH THE WEEKEND. EVEN COASTAL AREAS MAY
SEE A THUNDERSTORM OR TWO THURSDAY. COOLER AND DRIER NEXT WEEK AS A
TROUGH OF LOW PRESSURE MOVES IN ALONG THE WEST COAST.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
MORNING SOUNDING CONTINUES TO SHOW A MOIST AND UNSTABLE
ATMOSPHERE...WITH 1.65 INCHES OF PRECIPITABLE WATER AND 780 J/KG OF
MOST UNSTABLE CAPE. THE SOUNDING ALSO SHOWS MORE OF AN EASTERLY
COMPONENT TO THE WINDS IN THE LOW LEVELS. VISIBLE SATELLITE SHOWS
CIRRUS BLOW-OVER FROM LINDA MOVING IN FROM THE SOUTH...OBSCURING
PARTS OF SAN DIEGO COUNTY AND THE COACHELLA VALLEY. ALTHOUGH THESE
CLOUDS COULD HELP REDUCE TEMPERATURES A TINY BIT FOR THOSE
AREAS...THERE IS STILL EXPECTED TO BE ENOUGH SUNSHINE TO CREATE
ENOUGH INSTABILITY FOR THUNDERSTORMS TO ERUPT AGAIN THIS AFTERNOON
AND EARLY EVENING. THE WRF SHOWS THE SURFACE CONVERGENCE BOUNDARY
SETTING UP FARTHER WEST TODAY...OVER THE COASTAL FOOTHILLS...SO THAT
COULD BE WHERE THUNDERSTORMS INITIATE. THE HRRR AND OTHER HI-RES
MODELS FOCUS MUCH OF THE THUNDERSTORM ACTIVITY FOR THE RIVERSIDE AND
SAN BERNARDINO COUNTY AREAS...INCLUDING THE MOUNTAINS...THE INLAND
EMPIRE AND THE HIGH DESERTS...SO POPS HAVE BEEN ADJUSTED UPWARDS IN
THOSE LOCATIONS. WITH THE WRF SHOWING 700-500 MB WINDS OUT OF THE
EAST OF AROUND 10-15 KT...THIS SHOULD ALSO HELP WITH THUNDERSTORMS
DRIFTING IN THE VALLEY AREAS TODAY.
ON THURSDAY...PRECIPITABLE WATER INCREASES TO 2 INCHES ACCORDING TO
THE GFS AND NAM...AS THE CIRCULATION OF LINDA MOVES NORTHWEST TO A
POSITION FAR WEST OF NORTHERN BAJA...RESULTING IN CONTINUED EAST TO
SOUTHEAST FLOW BRINGING THE MOISTURE INTO THE AREA. WRF SHOWS THE
EAST WINDS IN THE 700-500 MB LAYER INCREASING TO 20 KT...WHICH MEANS
THAT STORMS SHOULD BE MOVING QUICKER AND THAT THEY MAY BE ABLE TO
DRIFT INTO COASTAL AREAS AS WELL. ONE POSSIBLE LIMITING FACTOR ON
THURSDAY IS IF THERE IS TOO MUCH CLOUD COVER...WHICH COULD DECREASE
THE AMOUNT OF INSTABILITY. THERE IS STILL A FAIR AMOUNT OF MOISTURE
IN THE REGION ON FRIDAY...WITH PRECIPITABLE WATER ONLY DECREASING TO
1.7-1.8 INCHES UNDER SOUTHEAST FLOW ALOFT...SO THUNDERSTORMS ARE
LIKELY TO DEVELOP AGAIN FRIDAY AFTERNOON AND EARLY EVENING IN THE
MOUNTAINS AND VALLEYS. THE AFTERNOON AND EARLY EVENING THUNDERSTORM
THREAT CONTINUES FOR THE MOUNTAINS AND DESERTS SATURDAY WITH
MOISTURE DIMINISHING A LITTLE...AND THEN THE GFS SHOWS MOISTURE
DECREASING FURTHER ON SUNDAY. FOR DETAILS ON THE FLASH FLOOD
THREAT...PLEASE SEE THE HYDROLOGY SECTION BELOW.
THE HEAT AND MUGGY CONDITIONS IS THE OTHER STORY...AS OVERNIGHT LOWS
WERE ONLY IN THE LOW TO MID 70S. THE LOW OF 77 DEGREES AT LINDBERGH
FIELD WAS ONE DEGREE BELOW THE ALL-TIME HIGHEST MINIMUM TEMPERATURE.
WITH THE RIDGE ALOFT CONTINUING TO BUILD OVER THE REGION...TODAY
WILL LIKELY BE THE HOTTEST DAY FOR MOST AREAS...WITH DAY-TIME HIGHS
REACHING 10 TO 15 DEGREES ABOVE NORMAL...ALTHOUGH THE DESERTS WILL
PROBABLY BE A LITTLE COOLER DUE TO INCREASED MOISTURE AND LOWERING
850 MB TEMPERATURES. SOME EASTERLY DOWNSLOPE FLOW ASSOCIATED WITH
THE CIRCULATION OF LINDA COULD BRING CONTINUED HOT CONDITIONS TO THE
SAN DIEGO COUNTY COAST AND VALLEYS THURSDAY AS WELL. A SLOW COOLING
TREND LOOKS TO START FRIDAY INTO SATURDAY...WITH MORE SIGNIFICANT
COOLING SUNDAY INTO EARLY NEXT WEEK AS THE RIDGE WEAKENS AND WE GET
A TROUGH ALONG THE WEST COAST. NIGHT AND MORNING MARINE LAYER CLOUDS
COULD RETURN BY SATURDAY NIGHT.
&&
.AVIATION...
091600Z...GENERALLY...NO VIS RESTRICTIONS TODAY AND
TONIGHT WITH OCCASIONAL CLOUDS ABOVE 10000 FEET MSL. BETWEEN 19-01Z
TODAY...THUNDERSTORMS ARE POSSIBLE IN THE MOUNTAINS...DESERTS AND
VALLEYS WITH BASES 8000 FEET MSL AND TOPS TO 45000 FEET. EXPECT
STRONG UPDRAFTS AND DOWNDRAFTS...SMALL HAIL...AND SURFACE GUSTS OVER
35 KT NEAR ANY STORM. IN STORMS LOCAL VIS REDUCED TO 2SM IN HEAVY
RAIN AND/OR BLOWING DUST IN DESERTS. CONFIDENCE IN THE FORECAST OF A
VERY LOW RISK OF LOW CLOUDS FOR KSAN TONIGHT IS HIGH...WITH EVEN
LESS RISK OF LOW CLOUDS AT KONT OVERNIGHT TONIGHT.
&&
.MARINE...
800 AM...THERE IS A SLIGHT CHANCE OF A THUNDERSTORM THURSDAY
AFTERNOON AND EVENING NEAR THE COAST. OTHERWISE...NO HAZARDOUS
MARINE WEATHER IS EXPECTED THROUGH SUNDAY.
&&
.BEACHES...
800 AM...A NEW SOUTH SOUTHEAST SWELL FROM HURRICANE LINDA WILL
ARRIVE THURSDAY. THIS SWELL WILL PRODUCE 5-7 FOOT SURF AT ORANGE
COUNTY BEACHES THURSDAY INTO FRIDAY WITH A FEW HIGHER SETS. THERE IS
A SLIGHT CHANCE OF THUNDERSTORMS AT THE BEACHES THURSDAY AFTERNOON
AND EVENING.
&&
.HYDROLOGY...
WITH THUNDERSTORMS EXPECTED TO DEVELOP IN THE INLAND VALLEYS OF SAN
DIEGO COUNTY TODAY...THIS AREA HAS BEEN ADDED TO THE FLASH FLOOD
WATCH.
MODERATE TO HIGH FLASH FLOOD THREAT CONTINUES TODAY FOR THE
MOUNTAINS...DESERTS AND THE VALLEYS...AS THE ATMOSPHERE WILL REMAIN
MOIST AND UNSTABLE THROUGH THAT TIME. THIS WILL CREATE THE CHANCES
FOR THUNDERSTORMS PRODUCING HEAVY RAIN. THE WINDS ALOFT WILL BE
SOMEWHAT WEAK AS WELL...RESULTING IN SOME SLOW MOVING STORMS WHICH
WILL INCREASE THE THREAT OF FLASH FLOODING FURTHER. RAIN RATES OF 1
TO 2 INCHES PER HOUR WILL BE POSSIBLE UNDERNEATH THE HEAVIER STORMS.
THE FLASH FLOOD WATCH CONTINUES THROUGH THURSDAY FOR THESE
AREAS...ALTHOUGH STORMS MAY BE MOVING QUICKER ON THURSDAY WHICH
COULD DIMINISH THE FLASH FLOOD THREAT A BIT. THE THREAT LOWERS
FURTHER FRIDAY INTO THE WEEKEND AS MOISTURE SLOWLY DECREASES.
&&
.SKYWARN...
SKYWARN ACTIVATION IS REQUESTED FOR NOON TODAY THROUGH EARLY EVENING
FOR SAN BERNARDINO...RIVERSIDE AND SAN DIEGO COUNTIES.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...FLASH FLOOD WATCH THROUGH THURSDAY EVENING FOR APPLE AND LUCERNE
VALLEYS-COACHELLA VALLEY-RIVERSIDE COUNTY MOUNTAINS-SAN
BERNARDINO COUNTY MOUNTAINS-SAN BERNARDINO AND RIVERSIDE
COUNTY VALLEYS-THE INLAND EMPIRE-SAN DIEGO COUNTY DESERTS-
SAN DIEGO COUNTY MOUNTAINS-SAN DIEGO COUNTY VALLEYS-SAN GORGONIO
PASS NEAR BANNING.
HEAT ADVISORY UNTIL 6 PM PDT THURSDAY FOR ORANGE COUNTY INLAND
AREAS-SAN BERNARDINO AND RIVERSIDE COUNTY VALLEYS-THE
INLAND EMPIRE-SAN DIEGO COUNTY COASTAL AREAS-SAN DIEGO
COUNTY VALLEYS-SANTA ANA MOUNTAINS AND FOOTHILLS.
PZ...NONE.
&&
$$
PUBLIC/HYDROLOGY...HARRISON
AVIATION/MARINE/BEACHES...SMALL
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
215 PM MDT WED SEP 9 2015
.SHORT TERM...(TONIGHT THROUGH THURSDAY NIGHT)
ISSUED AT 215 PM MDT WED SEP 9 2015
DRY WEST NORTHWEST FLOW PREVAILS AND KEEPS MOISTURE SOUTH OF OUR
SOUTHERN BORDER. THERE IS REMOTE CHANCE THAT A BRIEF SHOWER/STORM
FORMS OVER THE ERN SAN JUAN MOUNTAINS. WATER VAPOR SHOWS
PRONOUNCED DRY LAYER ACROSS THE SOUTH...AND COULD BE ONE REASON
WHY THE HRRR MODEL SHOWS NO SHOWERS/STORMS ACROSS THE SRN
MOUNTAINS AND FOOTHILLS.
STABLE CONDITIONS CONTINUE THURSDAY KEEPING CONDITIONS DRY AND
WINDS UPSLOPE/DOWNSLOPE INDUCED. VERTICAL PROFILES INDICATE WINDS
BELOW 600 MB WILL BE VERY LIGHT - LESS THAN 15 KTS AND NEAR NON-
EXISTENT AT THE SURFACE ON THURSDAY...WITH THE EXCEPTION OF THE
SOUTHWEST COLORADO VALLEYS WHERE WINDS ALOFT AT 300 MB ARE STILL
40 KTS THROUGH THURSDAY EVENING SO SOME HIGHER GUSTS (TO 20 MPH
OR SO) MAY MIX DOWN TO THE SURFACE. TEMPERATURES WILL REMAIN
ABOVE NORMAL.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 215 PM MDT WED SEP 9 2015
VERY LITTLE CHANGE IN THE MID RANGE FORECAST PERIOD AS HIGH
PRESSURE PERSISTS. ALONG THE WEST COAST...A TROUGH DEVELOPS ON
SATURDAY AND WHAT HAPPENS WITH THIS SYSTEM IS OUR NEXT FORECAST
CHALLENGE. THE 12Z GFS INDICATES A SMALL CLOSED LOW DEVELOPING IN
SOUTHERN UTAH AND PROPAGATING INTO WESTERN COLORADO ON MONDAY
WHILE THE EC BRINGS AN OPEN WAVE TROUGH INTO THE FOUR CORNERS.
BOTH SOLUTIONS BRING PRECIPITATION TO THE REGION...SO CONFIDENCE
IS GOOD ON AN INCREASE IN MOISTURE AND THE POSSIBILITY OF RAIN
EARLY NEXT WEEK. TUESDAY LOOKS QUITE BREEZY AND WET WITH EITHER
MODEL SOLUTION AS A COLD 700 MB LOW PRESSURE SYSTEM BARRELS DOWN
INTO THE NORTHERN ROCKIES ON TUESDAY INTERACTING WITH THE MUCH
WARMER AIR IN PLACE TO THE SOUTH. THERE HAVE BEEN PRETTY MAJOR
FLUCTUATIONS RUN TO RUN IN THE FORECAST MODELS FOR EARLY NEXT
WEEK AS THE PATTERN TRANSITIONS...SO DETAILS WILL HAVE TO BE
IRONED OUT AS A SOLUTION BECOMES MORE CONSISTENT. THE GENERAL
PATTERN DOES LOOK WETTER AND COOLER NEXT WEEK WITH AN AUTUMN-LIKE
LOOK TO THE PATTERN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1126 AM MDT WED SEP 9 2015
NO SIGNIFICANT WEATHER OR AVIATION HAZARDS ARE EXPECTED THROUGH
THE TIME PERIOD. VFR AND MOSTLY P6SM SKC WITH LIGHT DIURNAL WIND
CIRCULATIONS.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...PF/JAM
LONG TERM...JAM
AVIATION...PF
AREA FORECAST DISCUSSION
NWS TAUNTON MA
335 PM EDT WED SEP 9 2015
.SYNOPSIS...
A COLD FRONT WILL SLOWLY MOVE INTO THE REGION TONIGHT BEFORE
STALLING NEAR THE SOUTH COAST THURSDAY. LOW PRESSURE WILL TRACK
SOUTH OF NEW ENGLAND THURSDAY INTO FRIDAY BRINGING WIDESPREAD
SHOWERS AND SOME THUNDERSTORMS...ALONG WITH HEAVY RAINFALL AT
TIMES. AS AN AREA OF LOW PRESSURE DEPARTS ON FRIDAY...A LULL IN
THE WEATHER WILL FOLLOW PRIOR TO AN ANOMALOUS WEATHER SYSTEM FOR
THE WEEKEND WHICH WILL LIKELY BRING THE AREA SOME RAIN FOR SUNDAY.
AS THE SYSTEM EXITS...MILDER WEATHER WILL FOLLOW WITH ABOVE-
AVERAGE TEMPERATURES BENEATH HIGH PRESSURE INTO NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
RECORD MAX TEMP HAS BEEN SET AT BOS AND BDL. SO FAR PVD IS ONE
DEGREE SHY OF THE RECORD.
RADAR SHOWS WIDELY SCT SHOWERS AND PERHAPS AN EMBEDDED TSTM MOVING
INTO W MA. MLCAPES CLOSE TO 1000 J/KG WITH EFFECTIVE SHEAR 30 KT
SO CANT RULE OUT AN ISOLD STRONG STORM BUT HRRR WEAKENS THE
CONVECTION AS IT MOVES EAST INTO A LESS FAVORABLE ENVIRONMENT.
MORE WIDESPREAD CONVECTION AHEAD OF THE COLD FRONT WAS MOVING
EAST FROM CENTRAL AND NORTHERN NY. THIS AREA WAS ASSOCD WITH
DECENT LOW LEVEL FRONTOGENESIS AND MLCAPES UP TO 1000 J/KG. MODELS
BRING THIS FRONTOGENESIS INTO THE REGION THIS EVENING BUT
INSTABILITY IS FORECAST TO WEAKEN TOWARD 00Z SO WE EXPECT
WEAKENING LINE OF CONVECTION MOVING INTO THE THE REGION FROM THE
WEST AROUND OR AFT 00Z PER HIRES ARW/NMM.
COLD FRONT MOVES SLOWLY EAST ACROSS SNE TONIGHT REACHING THE
COASTAL PLAIN TOWARD 00Z. WE WILL LIKELY SEE A LULL IN ACTIVITY
OVERNIGHT ALTHOUGH CANT RULE OUT A FEW SHOWERS OR AN ISOLD
TSTM...ESPECIALLY COASTAL PLAIN LATER TONIGHT WITHIN THE LOW LEVEL
THETA-E RIDGE AHEAD OF THE COLD FRONT.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
*** LOCALLY HEAVY RAINFALL LIKELY THURSDAY INTO THURSDAY NIGHT ***
INSTABILITY AXIS DEVELOPS ACROSS THE COASTAL PLAIN IN THE MORNING
WITHIN THE THETA-E RIDGE AND WILL LIKELY SEE A GENERATION OF
SHOWERS AND TSTMS ACROSS E CT...RI AND SE MA THU MORNING ALONG THE
FRONTAL BOUNDARY. GIVEN PWATS INCREASING OVER 2 INCHES...LOCALLY
HEAVY RAINFALL IS POSSIBLE.
THE FRONT IS EXPECTED TO STALL NEAR THE SOUTH COAST AS LOW PRES
DEVELOPS OVER THE MID ATLC COAST...THEN LIFTING NE AND TRACKING
SOUTH OF NEW ENGLAND THU NIGHT. CLASSIC COLD SEASON SCENARIO WITH
LOW LEVEL FRONTOGENESIS AND CONVERGENCE DEVELOPING ON THE NW
PERIPHERY OF SFC LOW AND MID LEVEL CENTER WITHIN RIGHT ENTRANCE
REGION OF THE UPPER JET. THE BEST LOW LEVEL FORCING BECOMES
ALIGNED ACROSS W NEW ENG SO WE EXPECT FOCUS FOR HEAVIER RAINFALL
TO SHIFT TO THE WEST ACROSS W MA AND N CT DURING THU AFTERNOON
INTO THU NIGHT...EVENTUALLY REACHING THE COAST LATE THU NIGHT INTO
EARLY FRI. SFC INSTABILITY IS LIMITED IN THE WEST ON THE COOL
SIDE OF THE BOUNDARY BUT THERE IS ENOUGH ELEVATED INSTABILITY FOR
A FEW TSTMS. ANOMALOUS PWATS SUGGEST LOCALLY HEAVY RAINFALL WILL
BE THE PRIMARY THREAT WITH AREAS OF URBAN AND POOR DRAINAGE
FLOODING POSSIBLE. RAINFALL AMOUNTS OF 1 TO 2 INCHES WITH LOCALLY
HIGHER AMOUNTS POSSIBLE WITH AXIS OF HEAVIEST RAINFALL LIKELY
ACROSS WESTERN NEW ENGLAND. LESSER RAINFALL AMOUNTS EXPECTED IN
SE NEW ENG.
MUCH COOLER THU WITH MAX TEMPS MOSTLY IN THE 70S...BUT MAY REACH
80 ACROSS PORTIONS OF RI AND E MA. STILL QUITE HUMID IN E NEW ENG
WITH DEWPOINTS NEAR 70.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
HIGHLIGHTS...
* SHOWERS DISSIPATING THROUGH THE DAY FRIDAY
* A LULL IN THE WEATHER AROUND SATURDAY
* RETURN OF WET-WEATHER AND POSSIBLE THUNDERSTORMS FOR SUNDAY
* LOOKING DRY WITH ABOVE- AVERAGE TEMPERATURES INTO NEXT WEEK
DISCUSSION...
AN ANOMALOUS WEEKEND SETUP INTO EARLY NEXT WEEK THAT WARRANTS AN
ENSEMBLE FORECAST APPROACH. GOOD AGREEMENT ON A DEEP TROUGH PATTERN
EVOLVING INTO A QUASI CUT-OFF CLOSED LOW OVER THE OHIO RIVER VALLEY
REGION OVER THE WEEKEND...DEAMPLIFYING AS AN OPEN-WAVE OVER THE NE
EARLY NEXT WEEK. THEREAFTER ENSEMBLE MEANS CONTINUE TO ADVERTISE
RIDGING ACROSS THE REGION WITH PREFERRED TROUGHING TO THE W AND A
MAINTAINED AREA OF LOW PRESSURE OVER THE N ATLANTIC. APPEARANCES
WOULD LEAD TO BELIEVE THAT SUMMER IS NOT OVER QUITE YET AS THE 8-14
DAY FORECASTS FROM THE CLIMATE PREDICTION CENTER HAVE INCREASED
ABOVE-AVERAGE TEMPERATURE PROBABILITY. NORMALS FOR MID-SEPTEMBER ARE
AROUND THE LOW- TO MID-70S FOR HIGHS WITH LOW- TO MID-50S FOR LOWS.
FRIDAY INTO SATURDAY...
SOME INITIAL SHOWERS AND CLOUDY CONDITIONS TO START ON FRIDAY SHOULD
BREAK W TO E AS DRIER AIR MOVES IN AND SUBSIDENCE PROCEEDS BENEATH
RIDGING AHEAD OF THE CLOSED-LOW OVER THE OHIO RIVER VALLEY EXPECT A
LULL IN THE WEATHER-ACTIVITY FRIDAY INTO SATURDAY...THOUGH UNCERTAIN
AS TO WHEN IT WILL RE-EMERGE SATURDAY INTO SUNDAY. IT DOES APPEAR
BASED ON ENSEMBLE MEANS THAT THE RIDGE LIFTS NE SATURDAY-SUNDAY AS
THE CLOSED LOW IS RECAPTURED BY THE MARITIME FLOW DEAMPLIFYING AS
AN OPEN-WAVE MONDAY-TUESDAY. PROGRESS OF AN ACCOMPANYING WARM-
FRONTAL BOUNDARY ALONG WHICH THERE IS AN INCREASING UPSLOPE
MAGNITUDE OF HIGHER THETA-E AIR BENEATH GROWING DIFFLUENCE ALOFT
WARRANTS CHANCE POPS OVER THE MAJORITY OF THE AREA BEGINNING
SATURDAY NIGHT. WILL GO AHEAD WITH SOME ELEVATED THUNDER CHANCES
BUT KEEP THEM ISOLATED AS INSTABILITY APPEARS MARGINAL IN A
MODERATELY SHEARED ENVIRONMENT.
SUNDAY INTO MONDAY...
LIKELY RAIN WITH EMBEDDED THUNDER AND HEAVIER SHOWERS AS AN ENHANCED
H925-85 FLOW WRAPS CYCLONICALLY AROUND THE DEAMPLIFYING CLOSED-LOW
NE OF THE REGION. A QUASI-TROWALING SETUP COLLOCATED WITH STRONG
CONVERGENT ISENTROPIC-UPSLOPE SIGNATURES BENEATH DIFFLUENCE ALOFT...
THE POTENTIAL FLY-IN-THE-OINTMENT COULD BE THE POSSIBILITY OF THE
GREATER ENHANCED FORCING REMAINING W OF THE REGION ASSOCIATED WITH
THE DEAMPLIFYING CLOSED-LOW OVER THE E GREAT LAKES AND/OR THE MODEL
CONSENSUS OF NEW ENGLAND BEING BENEATH THE RIGHT-EXIT REGION OF THE
UPPER-LEVEL JET...YIELDING A LESS FAVORABLE AREA OF LIFT.
ASIDE...THE APPARENT LOW-MID LEVEL LIFT AND CONVERGENCE OF THETA-E
YIELDS THE LIKELIHOOD OF RAIN. BUT THE QUICKLY-FOLLOWING PUNCH OF
DRIER AIR WRAPPING INTO THE OCCLUDING SYSTEM MAKES THE WET-WEATHER
PERIOD BRIEF. MOST OF THE ACTIVITY MAY RESIDE ON SUNDAY WITH DRY
WEATHER PREVAILING SUNDAY NIGHT.
ONLY A RENEWED CHANCE MAY EMERGE ON MONDAY ASSOCIATED WITH THE COMMA-
HEAD TROWAL OF THE LOW WHERE H85-5 TEMPERATURES DROP CONSIDERABLY.
H5 TEMPERATURES NEAR -20C. FOCUS ALONG A COLD FRONT AS POSSIBLY THE
BOUNDARY-LAYER DESTABILIZES AHEAD SUBSEQUENT OF THE PUNCH OF DRY AIR
COULD RESULT IN SOME LOW-TOPPED ACTIVITY. SOME SPATIAL VARIABILITY
WITH RESPECT TO ATMOSPHERIC FEATURES THUS ONLY WILLING TO GO WITH
CHANCE POPS MAINLY OUT TO THE W. WILL GO WITH AT OR BELOW-AVERAGE
TEMPERATURES FOR THE PERIOD.
PRESENTLY NOT SEEING MUCH IN THE WAY OF IMPACTS WITH RESPECT TO THE
WET-WEATHER. HIGHER THETA-E VALUES LOOK TO REMAIN OFFSHORE WITHIN
THE ANTICYCLONIC BRANCH OF THE WARM-CONVEYOR BELT...ALSO GREATER
INSTABILITY.
TUESDAY AND BEYOND...
DRY WEATHER AS RIDGING PROCEEDS PER AN ENSEMBLE-WEIGHTED FORECAST.
WILL LEAN TOWARDS AN ABOVE-AVERAGE TEMPERATURE FORECAST IN AGREEMENT
WITH THE CLIMATE PREDICTION CENTER. CONTINUED STRONG SIGNALS OF SW-
FLOW PREVAILING ALOFT ADVECTING NE ACROSS THE REGION A WARM-HUMID
AIRMASS.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH THURSDAY/...
THROUGH 00Z...VFR. ISOLD SHOWERS OR PERHAPS A TSTM IN W NEW ENG.
TONIGHT...MODERATE CONFIDENCE. AREAS OF IFR/LIFR STRATUS AND
PATCHY FOG LIKELY DEVELOPING TONIGHT...ESPECIALLY NEAR THE S
COAST. MOSTLY VFR ELSEWHERE WITH SOME PATCHY MVFR FOG IN SPOTS.
WEAKENING LINE OF SHOWERS/TSTMS MOVING INTO W MA AND N CT THIS
EVENING WITH LOW PROB OF A BRIEF SHOWER/TSTM IN THE COASTAL PLAIN
OVERNIGHT.
THURSDAY...MODERATE CONFIDENCE. IFR CONDITIONS ALONG THE S COAST
IMPROVING TO MVFR/VFR. OTHERWISE...VFR GRADUALLY LOWERING TO MVFR
AS SHOWERS AND SCT TSTMS DEVELOP. FOCUS FOR SHOWERS/TSTMS WILL
INITIALLY BE ACROSS E CT/RI AND SE MA IN THE MORNING...THEN
GRADUALLY SHIFTING INTO WESTERN NEW ENG IN THE AFTERNOON. LOCALLY
HEAVY RAINFALL POSSIBLE.
THURSDAY NIGHT...MODERATE CONFIDENCE. CONDITIONS LOWERING TO IFR
IN SHOWERS/TSTMS AND PATCHY FOG. LOCALLY HEAVY RAINFALL POSSIBLE.
KBOS TERMINAL...MODERATE CONFIDENCE IN TAF.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF.
OUTLOOK /FRIDAY THROUGH MONDAY/...
FRIDAY...MODERATE CONFIDENCE.
MVFR-IFR MIX ALONG WITH -SHRA LIFTS E ALLOWING CONDITIONS TO IMPROVE
THROUGH THE DAY. N-WINDS WITH THE POSSIBILITY OF 20 KT GUSTS ACROSS
THE E-COAST.
SATURDAY...MODERATE CONFIDENCE.
VFR. WINDS VEERING E/SE. DRY FORECAST.
SUNDAY...MODERATE CONFIDENCE.
MVFR-IFR MIX WITH E/SE-ONSHORE FLOW. RAIN LIKELY ACROSS THE REGION.
MAY ALSO CONTEND WITH SOME LLWS IMPACTS.
MONDAY...MODERATE CONFIDENCE.
IMPROVING TO VFR BEGINNING SUNDAY NIGHT. W/SW-WINDS WITH GUSTS UP TO
20 KTS.
&&
.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.
STILL EXPECT SOME G25 KT ACROSS NEARSHORE WATERS NEAR CAPE COD
THROUGH THE REST OF THE AFTERNOON ASSOCD WITH MODEST LOW LEVEL
JET SO WE WILL CONTINUE THE SMALL CRAFT ADVISORY. THE JET MOVES
EAST TONIGHT AND WINDS WILL DIMINISH. VSBYS LOWERING IN PATCHY
FOG TONIGHT S COASTAL WATERS.
THU...WINDS BECOME NE LESS THAN 20 KT ACROSS E MA COASTAL WATERS
AS FRONT MOVES THROUGH BUT REMAINING S/SE OVER SOUTHERN WATERS.
VSBYS REDUCED IN SHOWERS AND POSSIBLE TSTMS AND FOG...ESPECIALLY
IN THE MORNING.
THU NIGHT...MAINLY E/NE WINDS BELOW SCA...BUT THERE IS LOW PROB
OF GUSTY NE WINDS DEVELOPING LATE ACROSS NE MA COASTAL WATERS.
VSBYS REDUCED AT TIMES IN SHOWERS/POSSIBLE TSTMS AND FOG.
OUTLOOK /FRIDAY THROUGH MONDAY/...
FRIDAY...MODERATE CONFIDENCE.
LOW PRESSURE LIFTING E. SHOWERS LINGER ACROSS THE WATER ALONG WITH
THE POSSIBILITY OF FOG. N-WINDS PREVAILING BACKING OUT OF THE NW.
INITIALLY COULD SEE GUSTS UP TO 25 KTS ACROSS THE E-WATERS LENDING
TO SEAS IN EXCESS OF 5-FEET. SMALL-CRAFT ADV MAY BE WARRANTED.
SATURDAY...MODERATE CONFIDENCE.
A LULL IN THE WEATHER. WINDS BECOME LIGHT WHILE VEERING E/SE. SHOULD
SEE SEAS SUBSIDE FOR THE PERIOD BELOW 5-FEET.
SUNDAY...MODERATE CONFIDENCE.
DEEPER AREA OF LOW PRESSURE TO THE W. WILL SEE AN ACCOMPANYING WARM
FRONT LIFT N ACROSS THE WATERS BRINGING WITH IT THE CHANCE OF RAIN
ALONG WITH INCREASING E/SE-ONSHORE WINDS. GUSTS UP TO 20 KTS
POSSIBLE. WAVE HEIGHTS BUILDING IN EXCESS OF 5-FEET PLAUSIBLE.
MONDAY...MODERATE CONFIDENCE.
THOUGH IMPROVING SUNDAY NIGHT...WINDS BACK OUT OF THE W/SW AND
REMAIN ROBUST WITH A STRONG AREA OF LOW PRESSURE SITUATED WELL TO
THE W ACROSS THE INTERIOR. ANOTHER DAY OF GUSTS UP TO 20 KTS WHILE
SEAS REMAIN AT OR IN EXCESS OF 5-FEET ON THE WATERS.
&&
.CLIMATE...
RECORD HIGH TEMPERATURES FOR WEDNESDAY...9/9
BOS...91 IN 1971
PVD...91 IN 1971
ORH...90 IN 1915
BDL...91 IN 2002
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
ANZ231>234.
SMALL CRAFT ADVISORY UNTIL 2 AM EDT THURSDAY FOR ANZ250.
&&
$$
SYNOPSIS...KJC/SIPPRELL
NEAR TERM...KJC
SHORT TERM...KJC
LONG TERM...SIPPRELL
AVIATION...KJC/SIPPRELL
MARINE...KJC/SIPPRELL
CLIMATE...
AREA FORECAST DISCUSSION
NWS TAUNTON MA
148 PM EDT WED SEP 9 2015
.SYNOPSIS...
HIGH PRESSURE SOUTH OF NEW ENGLAND WILL PUSH OFFSHORE LATE TODAY
THROUGH THURSDAY. A COLD FRONT WILL APPROACH LATE THIS
AFTERNOON...SLOWLY CROSSING THE REGION TONIGHT AND
THURSDAY...BEFORE STALLING ACROSS SOUTHEAST MASSACHUSETTS BY
THURSDAY NIGHT. EXPECTING WIDESPREAD SHOWERS AND SOME
THUNDERSTORMS...ALONG WITH HEAVY RAINFALL AT TIMES...WHICH MAY
CAUSE LOCALIZED FLOODING THURSDAY NIGHT INTO FRIDAY. A BRIEF LULL
FOLLOWS FOR SATURDAY PRIOR TO ANOTHER POTENTIAL BATCH OF RAIN
SUNDAY INTO MONDAY. A WARM AND DRY PATTERN LOOKS TO PREVAIL INTO
THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
145 PM UPDATE...
RECORD MAX TEMP HAS BEEN SET AT BOS AND TIED AT BDL. SO FAR PVD IS
ONE DEGREE SHY OF THE RECORD.
RADAR SHOWS WIDELY SCT SHOWERS ACROSS E NY WITH MORE WIDESPREAD
CONVECTION IN THE FORM OF A LINE ACROSS CENTRAL AND N NY ASSOCD
WITH THE COLD FRONT. HRRR SHOWS A FEW SHOWERS AND PERHAPS A TSTM
SPILLING INTO W NEW ENG MID/LATE AFTERNOON...BUT MAIN ACTIVITY
ASSOCD WITH GOOD LOW LEVEL FRONTOGENESIS REMAINS TO THE WEST.
MLCAPES UP TO 1000 J/KG ACROSS FAR W NW ENG AND E NY BUT
INSTABILITY IS FORECAST TO WEAKEN RAPIDLY TOWARD 00Z SO EXPECT WE
EXPECT WEAKENING LINE OF CONVECTION MOVING INTO THE REGION AROUND
OR AFT 00Z.
PREVIOUS DISCUSSION...
STILL SOME STRATUS ALONG THE IMMEDIATE S COAST WHICH MAY TAKE
UNTIL THE AFTERNOON TO BURN OFF...OTHERWISE MOSUNNY AND ANOTHER
HOT/HUMID DAY. NOT QUITE AS HOT AS YESTERDAY...BUT MAXES WILL
LIKELY REACH INTO THE LOWER 90S IN NE MA AND PORTIONS OF THE CT
VALLEY AND WELL INTO THE 80S ELSEWHERE. BEST CHANCE OF AT LEAST
TYING RECORD MAXES WILL BE AT BOS/BDL. IT WILL BE QUITE HUMID WITH
DEWPOINTS UPPER 60S TO LOWER 70S SO HEAT INDICES WILL GET INTO THE
LOW AND MID 90S. MODEST SW LOW LEVEL JET WILL LIKELY RESULT IN
SOME GUSTS TO 25 MPH ACROSS SE NEW ENG. WEDGE OF VERY DRY MID
LEVEL AIR ACROSS SNE THIS MORNING WILL MOVE OFFSHORE WITH COLUMN
MOISTENING THROUGH THE AFTERNOON. AIRMASS DESTABILIZES WITH CAPES
UP TO 1000 J/KG IN W NEW ENG AHEAD OF COLD FRONT WHICH MOVES
THROUGH NEW YORK STATE THIS AFTERNOON. HI-RES GUIDANCE SUGGESTS A
FEW SHOWERS/TSTMS COULD SPILL INTO W MA VERY LATE TODAY SO WILL
HAVE SLIGHT CHC POPS IN THE AREA. 0-6KM SHEAR INCREASES TO ABOUT
25 KT SO AN ISOLD STRONG STORM IS POSSIBLE BUT SEVERE WEATHER NOT
ANTICIPATED.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
COLD FRONT SLOWLY MOVES INTO THE REGION TONIGHT THROUGH MIDDAY
THU...THEN WILL STALL ACROSS SOUTHEASTERN AREAS BY THU EVENING. WITH
STEADY S-SW WIND FLOW IN PLACE...WILL SEE INCREASING MOISTURE FEED
UP THE COAST. PWATS INCREASE UP TO 2 INCHES...SO WILL LIKELY SEE
HEAVY RAINFALL ESPECIALLY ON THU AS THE FRONT SLOWS. WILL STILL SEE
SOME MARGINAL INSTABILITY IN PLACE...SO SOME ISOLD CONVECTION
REMAINS POSSIBLE. NOTING CAPES ACROSS NE CT/RI/SE MA AT AROUND 700-
800 J/KG...SO MIGHT SEE SOME GUSTY WINDS IN ANY THUNDERSTORMS THERE
DURING THURSDAY AFTERNOON. EXPECT HIGHS ON THU RANGING FROM THE MID
70S WELL INLAND TO THE LOWER 80S ACROSS SE AREAS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
HIGHLIGHTS...
* POTENTIAL FOCUSED AREA OF HEAVY RAIN THURSDAY NIGHT INTO FRIDAY
* THREAT OF URBAN / POOR-DRAINAGE FLOODING OVER NEW ENGLAND
* A LULL PRIOR TO RENEWED ACTIVITY SUNDAY INTO MONDAY
* LOOKING DRY AND WARMER INTO NEXT WEEK
DISCUSSION...
THURSDAY NIGHT THROUGH FRIDAY...
09/00Z GUIDANCE SUITE HAS NOT CHANGED MUCH FROM PREVIOUS THINKING.
PLENTY OF SYNOPTIC FORCING SHOULD MEAN WIDESPREAD SHOWERS ACROSS
SOUTHERN NEW ENGLAND FOR A PORTION OF THIS TIME PERIOD. HAVE HIGH
CONFIDENCE IN MEASURABLE RAINFALL ACROSS MOST OF SOUTHERN NEW
ENGLAND. STILL NEED TO IRON OUT WHAT THE UPPER LIMIT FOR RAINFALL
WILL BE...AND WHERE IT WILL FALL. AT THIS POINT...IT STILL APPEARS
THE AXIS FOR HEAVIEST RAINFALL WILL EXTEND NORTHEAST ACROSS
NORTHERN CT AND WESTERN AND CENTRAL MA.
THE MAJORITY OF RIVERS AND STREAMS ARE WELL BELOW NORMAL WITH
RESPECT TO STREAMFLOWS. AS LAKES AND RESERVOIRS ARE ALSO LOW...THE
SUBSEQUENT FOCUS REMAINS UPON URBAN AND POOR-DRAINAGE FLOODING.
CONVECTIVE INSTABILITY LOOKS RATHER MARGINAL...SO NOT EXPECTING
MANY STRONG THUNDERSTORMS. CANNOT COMPLETELY RULE OUT THAT
POSSIBILITY THOUGH. NEAR SEASONABLE TEMPERATURES.
THIS WEEKEND INTO EARLY NEXT WEEK...
FAIRLY GOOD AGREEMENT AMONG THE 09/00Z MODELS HEADING INTO THIS
WEEKEND...BREAKS DOWN TO SOME EXTENT SUNDAY INTO MONDAY. THE MAIN
ISSUE WILL BE THE PROGRESS OF A MODEST UPPER LOW...AND HOW
EFFECTIVE IT WILL BE TO SPAWN A COASTAL LOW OFF THE MID ATLANTIC
COAST. BOTH THE GFS AND ECMWF HAVE A POTENT SHORTWAVE IN PLACE TO
GENERATE THIS LOW PRESSURE...BUT HAVE RATHER DIFFERENT IDEAS ON
ITS TRACK AND TIMING.
HAVE MODERATE CONFIDENCE WE WILL SEE A PERIOD OF SHOWERS SOMETIME
SUNDAY INTO MONDAY. HAVE LOW CONFIDENCE IN THE PRECISE TIMING.
WILL JUST MENTION A CHANCE FOR SHOWERS SUNDAY INTO MONDAY...AND
AWAIT FURTHER CLUES ON HOW THIS WINDOW COULD BE NARROWED IN LATER
FORECASTS.
NEXT WEEK...
ENSEMBLE SOLUTIONS SIGNALING A RETURN TO A RIDGING PATTERN. COULD
BE LOOKING AT ANOTHER PRONOUNCED HOT AND HUMID PERIOD...AS HIGH
PRESSURE BUILDS S/E OF THE REGION. STILL HAVE RATHER LOW
CONFIDENCE IN THE FORECAST DETAILS.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH THURSDAY/...
THROUGH 00Z...VFR. ISOLD SHOWERS OR PERHAPS A TSTM IN W NEW ENG.
TONIGHT...MODERATE CONFIDENCE. AREAS OF IFR/LIFR STRATUS AND
PATCHY FOG LIKELY DEVELOPING TONIGHT...ESPECIALLY NEAR THE S
COAST. MOSTLY VFR ELSEWHERE WITH SOME PATCHY MVFR FOG IN SPOTS.
WEAKENING LINE OF SHOWERS/TSTMS MOVING INTO W MA AND N CT THIS
EVENING WITH LOW PROB OF A BRIEF SHOWER/TSTM IN THE COASTAL PLAIN
OVERNIGHT.
THURSDAY...MODERATE CONFIDENCE. IFR CONDITIONS ALONG THE S COAST
IMPROVING TO MVFR/VFR. OTHERWISE...VFR GRADUALLY LOWERING TO MVFR
AS SHOWERS AND SCT TSTMS DEVELOP. FOCUS FOR SHOWERS/TSTMS WILL
INITIALLY BE ACROSS E CT/RI AND SE MA IN THE MORNING...THEN
GRADUALLY SHIFTING INTO WESTERN NEW ENG IN THE AFTERNOON. LOCALLY
HEAVY RAINFALL POSSIBLE.
THURSDAY NIGHT...MODERATE CONFIDENCE. CONDITIONS LOWERING TO IFR
IN SHOWERS/TSTMS AND PATCHY FOG. LOCALLY HEAVY RAINFALL POSSIBLE.
KBOS TERMINAL...MODERATE CONFIDENCE IN TAF.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF.
OUTLOOK /THURSDAY NIGHT THROUGH SUNDAY/...
THURSDAY NIGHT INTO FRIDAY...HIGH CONFIDENCE IN TRENDS. MODERATE
CONFIDENCE IN TIMING.
A MIX OF LOW-END VFR TO IFR. IFR...ESPECIALLY WITH +RA/TSRA
FORECAST. S FLOW BACKING N OVER TIME. IMPROVING FRIDAY NIGHT.
SATURDAY...MODERATE CONFIDENCE.
VFR. WINDS VEERING E/SE.
SUNDAY...LOW CONFIDENCE.
LOW-END VFR TO IFR WITH INCREASING CHANCES OF RAIN. E WINDS
INCREASE...THEN BACK W/NW WITH TIME.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH THURSDAY/...HIGH CONFIDENCE.
1015 AM UPDATE...
WE EXPANDED THE SCA TO THE NEARSHORE WATERS ADJACENT TO CAPE COD
WHERE A FEW G25 KT EXPECTED THROUGH THE AFTERNOON.
SW WINDS WILL CONTINUE THROUGH THE PERIOD.
WILL SEE GUSTS UP TO 25 KNOTS AND SEAS AROUND 5 FT ON THE EASTERN
OUTER WATERS THIS AFTERNOON THROUGH AROUND MIDNIGHT TONIGHT. SMALL
CRAFT HAS BEEN ISSUED FOR THIS AREA. SOME GUSTS TO AROUND 20 KT
POSSIBLE THIS AFTERNOON AND EVENING ALONG THE S COASTAL NEAR SHORE
WATERS. WINDS BECOME LIGHT S-SW THOUGH MAY BE ONSHORE ALONG THE
EASTERN NEAR SHORE WATERS THU.
PATCHY FOG DEVELOPS TONIGHT WITH REDUCED VSBYS. SHOWERS DEVELOP FROM
S-N OVERNIGHT TONIGHT...WITH LOW RISK OF ISOLD TSTMS. BEST SHOT FOR
SHOWERS/ISOLD TSTMS WILL OCCUR DURING THU. FOG WILL ALSO LINGER.
OUTLOOK /THURSDAY NIGHT THROUGH SUNDAY/...
THURSDAY NIGHT INTO FRIDAY...MODERATE CONFIDENCE.
LOW PRESSURE SHOULD PASS ACROSS SOUTHERN NEW ENGLAND. INCREASING
SOUTH WINDS AHEAD OF THIS LOW COULD GENERATE SEAS APPROACHING 5
FEET ON THE E WATERS FOR THE LATE THURSDAY INTO FRIDAY PERIOD. IT
IS MORE LIKELY THESE BUILDING SEAS WILL DEVELOP IN THE NORTHEAST
FETCH ONCE THIS LOW PRESSURE IS FARTHER OFFSHORE. WILL SEE SOME
IMPROVEMENT INTO SATURDAY MORNING.
SATURDAY...MODERATE CONFIDENCE.
WINDS VEERING E/SE. GOOD BOATING WEATHER PREVAILS WITH SEAS BELOW
5 FEET.
SUNDAY...LOW CONFIDENCE.
ANOTHER AREA OF LOW PRESSURE AND RAIN. TRACK UNCERTAIN. COULD SEE
IMPACTS ON THE WATERS...THOUGH THEY MAY REMAIN MORE SOUTH AND EAST
COMPARED TO THURSDAY-FRIDAY.
&&
.CLIMATE...
RECORD HIGH TEMPERATURES FOR WEDNESDAY...9/9
BOS...91 IN 1971
PVD...91 IN 1971
ORH...90 IN 1915
BDL...91 IN 2002
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
ANZ231>234.
SMALL CRAFT ADVISORY UNTIL 2 AM EDT THURSDAY FOR ANZ250.
&&
$$
SYNOPSIS...BELK/EVT
NEAR TERM...KJC
SHORT TERM...EVT
LONG TERM...BELK
AVIATION...BELK/KJC
MARINE...BELK/EVT
CLIMATE...
AREA FORECAST DISCUSSION
National Weather Service Dodge City KS
1256 PM CDT WED SEP 9 2015
...Updated aviation section...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 313 AM CDT WED SEP 9 2015
The main forecast challenge for early this morning is areas of fog,
and or stratus and how dense. Moist weak northeasterly upslope flow
and with clear skies is allowing for good radiational cooling, and
causing areas of ground fog to develop and some stratus. Will carry
areas of fog in most areas this morning, but may need a dense fog
advisory in places especially near and west of Dodge City where the
NAM and the RAP model shows the highest boundary layer relative
humidity. The HRRR model also shows patchy dense fog in the
Garden City area. After the fog burns off by mid morning, expect
clearing skies and highs in the mid 80s. A surface high pressure
ridge will move east while a trough of low pressure develops in
the lee of the Rockies. Light and variable winds this morning
will become southeast to southerly at 10 mph with 10 to 20 mph far
west.
For tonight, expect mainly clear skies. A few thunderstorms could
develop late across the I-70 corridor as a jet streak moves in. Will
carry some small chances for rainfall, towards dawn. Overnight lows
will be in the lower 60s with light southeast winds becoming south
around 8 to 12 mph.
.LONG TERM...(Thursday THROUGH Tuesday)
ISSUED AT 339 AM CDT WED SEP 9 2015
For Thursday, an upper level shortwave trough in northwest flow
aloft will move across western Kansas pushing a cold front to near
Hays to Garden City and Elkhart by late afternoon. Ahead of the cold
front, warmer and moist south winds of 15 to 25 mph, will push highs
to around 90. Most models have thunderstorms developing by afternoon
ahead of the cold front, with a possible MCS (Mesoscale Convective
Complex) developing near and east of Dodge City by late afternoon
and evening. The cold front will continue to push across western
Kansas overnight with numerous thunderstorms developing. Some low
stratus is also suggested towards dawn behind the cold front.
Will carry around 50 percent chances in the afternoon and evening
with lesser chances north of Garden City where dewpoints are much
lower. Forecast instability is around 2000-3000 J/KG, but the NAM
is much higher and with dewpoints in the upper 60s. With 30kt at
mid levels and around 50 to 60kt aloft there could be some severe
thunderstorms with large hail from quarter to half dollar size,
and strong winds over 60 mph.
For Friday into next Tuesday, a dry period is forecast. A large
upper level trough will continue to dig into the Upper Midwest and
Mississippi Valley with much cooler surface high pressure moving
into the Plains. Highs on Friday and Saturday will be in the mid to
upper 70s. As the upper trough moves away from the region Sunday
into Tuesday, a warming trend will move back into the High Plains
with highs in the low 80s on Sunday, then mid to upper 80s on Monday
and Tuesday. Overnight lows will be in the 50s into Sunday morning,
the gradually warm to 60 to 65 degrees on Monday and Tuesday morning.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z Thursday AFTERNOON)
ISSUED AT 1253 PM CDT WED SEP 9 2015
Low clouds will dissipate over the next couple of hours leading to
VFR conditions for the remainder of the afternoon into the evening
hours. Winds will generally be from the south around 8 knots as
lee troughing redevelops across eastern Colorado.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 85 62 89 60 / 0 10 40 40
GCK 85 61 90 59 / 0 0 30 30
EHA 87 63 91 60 / 10 10 20 20
LBL 86 62 92 61 / 0 10 30 40
HYS 87 61 89 60 / 0 20 30 30
P28 85 63 89 64 / 0 10 20 50
&&
.DDC Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Kruse
LONG TERM...Kruse
AVIATION...Hovorka_42
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
310 PM EDT WED SEP 9 2015
.SHORT TERM (NOW THROUGH THURSDAY NIGHT)...
ISSUED AT 245 PM EDT WED SEP 9 2015
AS OF MID AFTERNOON...WATER VAPOR IMAGERY AND 500 MB HEIGHTS SHOWED
A SHORTWAVE TROUGH EXTENDING FROM THE GREAT LAKES DOWN ALONG THE
MISSISSIPPI RIVER...JUST WEST OF CENTRAL KENTUCKY. AT THE
SURFACE...THE ENVIORNMENT IS CHARACTERIZED BY WARM AND MOIST AIR
WITH DEWPOINTS IN THE LOW 70S. A COLD FRONT LIED ALONG THE OHIO
RIVER...SLOWLY MOVING EAST THROUGH THE AREA.
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS MAINLY IN THE WARM
SECTOR WILL CONTINUE THROUGH THE LATE AFTERNOON HOURS. THESE STORMS
WILL BE CAPABLE OF PROUDCING BRIEF BUT VERY HEAVY RAINFALL GIVEN THE
HIGH PWATS IN THE AREA. SOME GUSTY WINDS ARE POSSIBLE AS WELL.
HI-RES MODELS SUCH AS THE HRRR AND 12Z SPC WRF ARE IN GOOD AGREEMENT
SHOWING THE HIGHEST CHANCES NOW THROUGH EARLY EVENING...THEN A
DECREASE IN COVERAGE AS THE UPPER SHORTWAVE TROUGH KICKS THE FRONT
EAST THROUGH THE AREA. A SECONDARY LOW PRESSURE AND TROUGH NEAR
MEMPHIS WILL TRACK THROUGH CENTRAL TN TO SOUTHEAST KY
OVERNIGHT...KEEPING SOME SHOWERS AND STORMS IN THE FORECAST MAINLY
OVERNIGHT FOR THE SOUTHERN FORECAST AREA. AREAS NORTH OF THE KY
PARKWAYS INTO SOUTHERN INDIANA WILL PROBABLY SEE THE END OF THE RAIN
FROM THIS SYSTEM THIS EVENING OR EARLY OVERNIGHT.
LOW CLOUDS AND/OR FOG IS A CONCERN OVERNIGHT INTO THE THURSDAY
MORNING COMMUTE AS THE BOUNDARY LAYER WILL REMAIN VERY MOIST WITH
LIGHT WINDS. SREF PROBABIALITIES FOR LOW CLOUDS /500 FT OR LESS/ AND
FOG ARE BETWEEN 40 AND 60 PERCENT. WILL HAVE TO WATCH FOR LOCALLY
DENSE POCKETS OF FOG...ESPECIALLY IF THERE IS ANY CLEARING OR BREAKS
IN THE CLOUDS TOWARD SUNRISE.
IMPROVING CONDITIONS CAN BE EXPECTED DURING THE DAY THURSDAY. SOME
LINGERING SHOWERS AND MAYBE A THUNDERSTORM WILL BE POSSIBLE ALONG
AND SOUTHEAST OF A LEXINGTON TO BOWLNG GREEN LINE DURING THE MORNING
BUT THIS SHOULD QUICKLY MOVE EAST BY NOON. NORTHWEST WINDS WILL PICK
UP...HELPING TO SCATTER OUT OR LIFT SOME OF THE CLOUDS IN THE
AREA. LOOK FOR HIGHS RIGHT AROUND NORMAL IN THE LOW 80S.
.LONG TERM (FRIDAY THROUGH WEDNESDAY)...
ISSUED AT 305 PM EDT TUE SEP 8 2015
THE LONG TERM PERIOD WILL START OUT WITH A COLD FRONT PASSAGE ON
FRIDAY BRINGING SHOWERS/STORMS TO THE AREA FRI/FRI NIGHT. ALTHOUGH
THE OVERALL FORCING NEAR THE FRONT AND WIND SHEAR LOOK RELATIVELY
WEAK, THERE MAY BE ENOUGH SFC INSTABILITY TO PRODUCE A FEW STRONG
CELLS DURING THE AFTERNOON HOURS FRIDAY. OVERALL THOUGH, DON`T SEE
A BIG THREAT FOR ORGANIZED STRONG TO SEVERE CONVECTION FOR FRIDAY.
THE BIGGER STORY WITH THIS FRONT WILL BE THE STRONG UPPER LOW AND
MUCH COOLER AIRMASS FOLLOWING IT. WITH THESE FEATURES IN PLACE FOR
THE WEEKEND, LOOK FOR TEMPS TO BE 6 TO 12 DEGREES BELOW NORMAL.
SATURDAY WE`LL HAVE PLENTY OF LOW CLOUDS AND LINGERING SHOWERS
LIMITING HIGHS TO THE MID TO UPPER 60S. SOME MODEL DATA SUGGESTS
PERHAPS WE COULD SEE AN ISLD RUMBLE OF THUNDER WITH THIN, SHALLOW
INSTABILITY PRESENT IN THE SOUNDINGS. SHOWER ACTIVITY SHOULD
CONTINUE INTO SAT NIGHT BEFORE GRADUALLY ENDING FROM WEST TO EAST
SUN MORNING. HIGHS ON SUNDAY WILL BE SIMILAR TO SAT IN THE MID TO
UPPER 60S. LOW TEMPERATURES THIS WEEKEND WILL RANGE FROM THE MID
40S TO LOWER 50S WITH THE COOLEST NIGHT BEING SUN NIGHT INTO MONDAY
MORNING WHEN SKIES WILL BECOME CLEAR WITH THE HIGH PRESSURE CENTER
OVER THE REGION.
WE`LL REMAIN DRY MON-WED WITH RETURN FLOW BRINGING WARMER TEMPS BACK
INTO THE REGION. HIGHS ON MONDAY WILL WARM BACK INTO THE LOWER 70S
WITH UPPER 70S/LOWER 80S EXPECTED BY TUES/WED UNDER MOSTLY SUNNY
SKIES.
&&
.AVIATION (18Z TAF UPDATE)...
ISSUED AT 1258 PM EDT WED SEP 9 2015
MAINLY SHOWERS WILL AFFECT THE TERMINALS THROUGH THE OVERNIGHT
PERIOD. FOR THIS AFTERNOON...EXPECT COVERAGE TO BE MORE SCATTERED IN
NATURE WITH BRIEF DROPS TO MVFR POSSIBLE. SO FAR ACTIVITY HAS HAD
VERY LITTLE IN-CLOUD OR CLOUD TO GROUND LIGHTNING AND WITH LESS
COVERAGE...OPTED TO REMOVE VCTS FOR THIS AFTERNOON. LARGER BAND OF
RAIN SHOWERS WILL THEN SPREAD OVER SDF/LEX...BETWEEN 21-03Z WEST TO
EAST.
FOG/STRATUS BECOMES THE NEXT CONCERN AT ALL SITES FOR THE OVERNIGHT.
GUIDANCE IS HITTING LOW CLOUDS PRETTY HARD WITH IFR CONDITIONS BASED
ON A WELL SATURATED BOUNDARY LAYER. THE WIND FIELD WILL ALSO BE
LIGHT AND MOISTURE DOES LINGER WITH THE FRONT NEARBY. AS SUCH...THIS
ADDS CONFIDENCE TO WHAT THE GUIDANCE IS SUGGESTING...SO HAVE TRENDED
CEILINGS LOWER /IFR AT BWG AND LEX/ BUT THIS MAY NEED TO GO LOWER IN
FUTURE UPDATES. THERE MAY ALSO BE REDUCED VISIBILITY...POSSIBLY
DENSE FOG AT BWG. THE MAIN PERIOD FOR THE FOG/STRATUS RESTRICTIONS
WOULD BE 09-15Z. LOOK FOR SOME GRADUAL IMPROVEMENT WEST TO EAST
DURING THE MORNING THURSDAY AS WINDS BECOME NORTHWESTERLY HELPING TO
PUSH SLIGHTLY DRIER AIR IN.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
SHORT TERM........ZBT
LONG TERM.........AMS
AVIATION..........ZBT
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
302 PM CDT WED SEP 9 2015
.SYNOPSIS...
ISSUED AT 302 PM CDT WED SEP 9 2015
AS OF WEDNESDAY AFTERNOON THE UPPER AIR SYNOPTIC PATTERN OVER THE
CONTINUED TO BE HIGHLIGHTED BY A BROAD TROUGH ASSOCIATED WITH A LOW
SLOWLY MOVING TOWARD HUDSON BAY. THIS HAS THE NORTHERN AND CENTRAL
PLAINS IN RELATIVELY FAST NORTHWEST FLOW ALOFT. COOLER AIR IN THE
MID TO UPPER LEVEL OF THIS FLOW FOSTERED AN ENVIRONMENT
CHARACTERIZED BY STEEP LAPSE RATES AND ELEVATED INSTABILITY...WHICH
HAS AIDED IN THE FORMATION AND PERSISTENCE OF ISOLATED TO SCATTERED
THUNDERSTORM ACTIVITY IN CENTRAL NEBRASKA LATE IN THE MORNING AND
EARLY THIS AFTERNOON. AT THE SURFACE...A WEAK FRONT WAS SLOWLY
MOVING EAST ACROSS THE CWA. AS OF 20Z THE FRONT EXTENDED FROM JUST
EAST OF IMPERIAL AND NORTH PLATTE...NORTHEASTWARD TO NEAR AINSWORTH.
DRY WESTERLY WINDS BEHIND THE FRONT HAD DEWPOINTS DROPPING INTO THE
30S AND 40S ACROSS THE PANHANDLE AND WESTERN SANDHILLS. AHEAD OF
THE FRONT WINDS WERE SOUTHERLY AND DEWPOINTS REMAINED IN THE UPPER
50S AND 60S...WITH A CU FIELD DEVELOPING AS THE BOUNDARY LAYER
BECOMES MORE UNSTABLE. TEMPERATURES WERE GENERALLY IN THE MID 80S.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 302 PM CDT WED SEP 9 2015
THUNDERSTORMS IN CENTRAL AND NORTH CENTRAL NEBRASKA SHOULD CONTINUE
TO SLOWLY PUSH EAST THROUGH THE REMAINDER AFTERNOON. CONVECTIVE
ACTIVITY HAS ACCELERATED OVER CENTRAL ROCK AND HOLT COUNTY. SOME
LOCATIONS ARE RECEIVING HEAVY RAINFALL DUE TO TRAINING
STORMS...HOWEVER LATEST FFG IN THIS AREA IS QUITE HIGH. ADDITIONAL
SURFACE BASED SHOWERS AND THUNDERSTORM DEVELOPMENT HAS BEGUN IN FAR
SOUTHWEST NEBRASKA AND NORTHWEST KANSAS ALONG AN EASTWARD
PROGRESSING FRONT. HRRR HAS FAVORED AREAS JUST EAST OF A NORTH
PLATTE TO THEDFORD MUCH OF THE DAY...AND THIS MATCHES UP WELL WITH
THE DEVELOPING CU FIELD ON SATELLITE SO THE FORECAST LOOKS ON TRACK.
UPPER LEVEL FORCING IS TOUGH TO DISCERN SO THE SPATIAL EXTENT OF THE
NEW CONVECTION IS NOT EXPECTED TO BE EXPANSIVE. MLCAPE VALUES 1500
J/KG AND 35-40 KTS DEEP LAYER SHEAR WILL SUPPORT A FEW STRONG TO
SEVERE STORMS...HOWEVER WIDESPREAD SEVERE WEATHER IS NOT EXPECTED.
THUNDERSTORMS PUSH EAST THIS EVENING AND BEGIN TO WANE AFTER DARK
WITH THE LOSS OF HEATING AND INSTABILITY.
WEAK SHORTWAVE TROUGH DIVES SOUTHEAST THROUGH THE AREA OVERNIGHT.
WINDS BECOME EASTERLY AS THE FRONT SLOWLY PUSHES JUST SOUTHEAST OF
THE CWA AND A LEE SIDE SURFACE LOW DEEPENS IN NORTHEAST COLORADO.
THIS WILL ALLOW LOW LEVEL MOISTURE TO CREEP BACK WESTWARD...WITH
ANOTHER ROUND OF FOG/STRATUS POSSIBLE FOR SOUTHWEST INTO CENTRAL
NEBRASKA. DID NOT INCLUDE PATCHY FOG IN THE FORECAST AT THIS TIME
SINCE MODEL GUIDANCE HAS BEEN SOMEWHAT INCONSISTENT WITH COVERAGE
AND SEVERITY OF VISIBILITY RESTRICTIONS. THE MOST FAVORABLE AREAS
FOR LOCALLY DENSE FOG FORMATION WILL LIKELY BE WHERE PRECIPITATION
FALLS LATER THIS EVENING.
AN AREA OF SURFACE HIGH PRESSURE BEGINS TO DROP OUT OF ALBERTA AND
INTO THE NORTHERN PLAINS ON THURSDAY. THIS WILL PUSH TEMPERATURES
DOWN A FEW DEGREES WITH HIGHS RANGING FROM THE LOW 70S TO LOW 80S
ACROSS THE CWA. MODELS ADVERTISE LIGHT QPF LATE IN THE AFTERNOON AS
A MID-LEVEL JET STREAK NOSES INTO THE CENTRAL PLAINS...BUT DID NOT
ADD ANY MENTION OF POPS TO THE SHORT TERM FORECAST JUST YET AS THE
BETTER CHANCES LOOK TO BE AFTER 00Z FRIDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 302 PM CDT WED SEP 9 2015
THE NAM REMAINS IN AGREEMENT WITH CURRENT FORECAST WITH A
DISTURBANCE DROPPING SOUTHEAST FROM SWRN SD INTO WRN NEBR
OVERNIGHT. THE GFS IS FASTER WITH THIS DISTURBANCE AND REMAINS
MOSTLY DRY. THEREFORE KEPT POPS LIMITED TO 20 PERCENT WEST OF A
LINE FROM GORDON THROUGH BROKEN BOW.
KEPT VERY NEAR PREVIOUS HIGHS FRIDAY AS EASTERLY WINDS BECOME
SOUTHEAST BY AFTERNOON AND WEAK WAA WILL NOT KICK IN UNTIL
AFTERNOON. THERE COULD ALSO BE A FEW SHOWERS AND CLOUDINESS
LINGERING AS WELL.
ON SATURDAY...A RETURN SOUTHERLY WIND RETURNS WITH HIGHS WARMING
TO NEAR 80 ACROSS THE WEST WHILE THE EAST REMAINS IN THE LOWER TO
MID 70S.
FOR SUNDAY THROUGH TUESDAY...ABOVE NORMAL TEMPERATURES. ZONAL FLOW
ALOFT ACROSS THE CENTRAL PLAINS SUNDAY WILL PERSIST INTO MONDAY AS
AN UPPER TROUGH DIGS INTO THE PACIFIC NORTHWEST. THIS WILL KEEP A
THERMAL RIDGE ACROSS THE REGION WITH HIGHS RANGING IN THE 80S. ON
TUESDAY...THE UPPER TROUGH WILL ADVANCE ACROSS MONTANA THROUGH
COLORADO WITH STRONG HEATING TO OCCUR IN ADVANCE ACROSS THE
CENTRAL PLAINS. FORECAST HIGH ARE 85 TO 90...ALTHOUGH THE
POTENTIAL IS THERE FOR HIGHS TO EXCEED 90 IN SOME AREAS OF WRN
NEBR. A COLD FRONT TUESDAY NIGHT TO COOL BACK HIGHS TO NEAR 75
NORTH AND NEAR 80 SOUTH. THE 12Z ECMWF HOWEVER IS MUCH WEAKER WITH
THE POST FRONTAL COOLDOWN AND SUGGESTS 80S STILL POSSIBLE. MAINLY
DRY THROUGH THE EXTENDED PERIODS...EXCEPT A SLIGHT CHANCE ERN
PNHDL TUESDAY AFTN...AND MOST AREAS TUESDAY NIGHT. LOOKS DRY
BEHIND THE FRONT FOR WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1223 PM CDT WED SEP 9 2015
MAIN CONCERNS FOR THE CURRENT TAF PERIOD IS THE ISOLATED THUNDERSTORMS
THIS AFTERNOON AND EVENING...AND THE POTENTIAL FOR SUB-VFR
CIGS/VISBYS LATE TONIGHT AND EARLY THURSDAY MORNING.
A LINE OF THUNDERSTORMS ARE ONGOING EARLY THIS AFTERNOON IN PARTS
OF CENTRAL NEBRASKA...WITH REDEVELOPMENT TO THE WEST AND NORTH
POSSIBLE LATER THIS AFTERNOON AND EVENING. DID NOT FEEL CONFIDENT
ENOUGH IN THE SPATIAL EXTENT OF THUNDERSTORM ACTIVITY TO INCLUDE
IN THE TAF AT KLBF. ALL MODEL GUIDANCE AND OBSERVATIONAL TRENDS
SUGGEST THE ACTIVITY SHOULD REMAIN SOUTH AND EAST OF KVTN.
FOG AND LOW STRATUS MAY DEVELOP OVERNIGHT...GENERALLY FROM
SOUTHWEST INTO NORTH CENTRAL NEBRASKA...INCLUDING
KLBF...KBBW...KONL. INTRODUCED MVFR CIGS/VISBYS INTO THE TAF TO
SUGGEST THE POTENTIAL...ALTHOUGH THEY MAY NEED TO BE LOWERED INTO
IFR SHOULD FORECASTER CONFIDENCE INCREASE.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MARTIN
SHORT TERM...MARTIN
LONG TERM...ROBERG
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
310 PM MDT WED SEP 9 2015
.SYNOPSIS...
SCATTERED THUNDERSTORMS OVER CENTRAL NEW MEXICO WILL TAPER OFF THIS
EVENING. THE COVERAGE OF STORMS WILL FOCUS OVER SOUTHWEST NEW MEXICO
ON THURSDAY. DRIER AIR SETTLING INTO NORTHERN NEW MEXICO TONIGHT AND
THURSDAY NIGHT WILL ALLOW LOW TEMPERATURES TO SETTLE INTO THE 30S
AND 40S. A BACK DOOR COLD FRONT WILL SHIFT DOWN THE EASTERN PLAINS
ON FRIDAY ALLOWING FOR ANOTHER UPTICK IN STORMS. HIGH TEMPERATURES
WILL FALL BELOW NORMAL WITH MANY AREAS STAYING IN THE 70S. ISOLATED
STORMS ARE EXPECTED OVER THE WEEKEND BEFORE THE NEXT INCREASE IN
COVERAGE DEVELOPS MONDAY AND TUESDAY.
&&
.DISCUSSION...
THE COMBINATION OF A 40-50KT 300MB JET CORE AND MOIST UNSTABLE
UPSLOPE FLOW ALONG THE EAST SLOPES OF THE CENTRAL MT CHAIN TODAY
HAS LED TO A FEW STRONG TO LOCALLY SEVERE STORMS. SPC SSEO PICKED
UP ON THE COVERAGE AREA VERY WELL. HRRR AND LOCAL WRF SHOW THIS
ACTIVITY TAPERING OFF DURING THE EVENING WHILE DRYING TAKES PLACE
FROM NORTH TO SOUTH. SFC DEWPOINTS FROM THE NAM12 SHOW UPPER 20S/
LOW 30S TONIGHT ACROSS THE NW HALF OF THE STATE...WHICH COMBINED
WITH RADIATIONAL COOLING WILL LEAD TO CHILLY TEMPS. ANGEL FIRE IS
EXPECTED TO HIT FREEZING FOR THE 1ST TIME SINCE AUGUST 5TH.
THE AXIS FOR MOIST INSTABILITY WILL SHIFT FARTHER SOUTH THURSDAY
INTO SW NM WHILE DRY AIR ALOFT CONTINUES PRESSING S/SE OVER NORTHERN
NM. A FEW STORMS ARE STILL LIKELY AS WEAKLY FAVORABLE UPPER LEVEL
JET DYNAMICS DRIFT SOUTH OUT OF COLORADO. AT THE SURFACE THE FIRST
SIGNS OF A BACK DOOR FRONT WILL FLIRT WITH THE FAR NE PLAINS THUS
PROVIDING YET ANOTHER FORCING MECHANISM WITHIN COLFAX AND UNION
COUNTIES. THIS FRONT WILL SURGE INTO EASTERN NM AND THRU GAPS IN
THE CENTRAL MT CHAIN FRIDAY. MEANWHILE A 590DM H5 HIGH CENTER
WILL BECOME POSITIONED OVERHEAD AND FOCUS MORE TERRAIN DOMINATED
STORM COVERAGE FRIDAY THROUGH THE WEEKEND.
EXTENDED MODEL GUIDANCE IS GOING TO HAVE A DIFFICULT TIME WITH
THE REMNANTS OF HURRICANE LINDA NEXT WEEK AS SEVERAL DISORGANIZED
UPPER LEVEL VORT FEATURES TAKE SHAPE ALONG THE WEST COAST. FOR NOW
IT APPEARS MONDAY/TUESDAY COULD FEATURE AN UPTICK IN STORM
COVERAGE AS A PORTION OF THE 700-500MB MOISTURE AXIS CROSSES NM.
GUYER
&&
.FIRE WEATHER...
A NEW CENTROID OF HIGH PRESSURE HAS TAKEN SHAPE OVER THE GREAT
BASIN. THIS WILL FUNNEL DRIER AIR OVER NM FROM THE NORTHWEST WITH
MINIMUM HUMIDITIES FALLING A FEW TO 14 DEGREES ACROSS THE FORECAST
AREA THURSDAY. SINCE LOW LEVEL FLOW WILL ALSO TAKE ON MORE OF A
SOUTHWESTERLY COMPONENT ON THURSDAY...THERE WILL BE A DOWNTICK IN
SHOWER AND THUNDERSTORM COVERAGE WITH MAINLY ISOLATED ACTIVITY
FAVORING LOCATIONS ALONG AND EAST OF THE CONTINENTAL DIVIDE.
A STRONGER BACK DOOR COLD FRONT FRIDAY WILL BRING WITH IT MORE
MOISTURE WITH AN UPTICK IN SHOWER AND THUNDERSTORM ACTIVITY ALONG
AND EAST OF THE CENTRAL MOUNTAIN CHAIN DURING THE AFTERNOON...THEN
AS FAR WEST AS THE CONTINENTAL DIVIDE DURING THE EVENING. THIS FRONT
IS FORECAST TO PRODUCE A MODERATELY GUSTY EAST CANYON WIND IN THE
MIDDLE AND LOWER RIO GRANDE VALLEY FRIDAY AND FRIDAY NIGHT. ANOTHER
CROP OF THUNDERSTORMS IS EXPECTED ALONG AND EAST OF THE CONTINENTAL
DIVIDE ON SATURDAY AS MOISTURE RECYCLES...BUT THERE WILL BE A
DOWNTICK IN COVERAGE.
THE UPPER HIGH IS FORECAST TO MIGRATE SOUTHEASTWARD TO AROUND THE NM
BOOT HEEL ON SUNDAY...THEN TO THE SE OF NM ON MONDAY AS AN UPPER
LEVEL TROUGH DEEPENS INTO A LOW PRESSURE SYSTEM ON THE WEST COAST
AND EJECTS SOME OF ITS SHORTWAVE ENERGY INLAND ACROSS THE CENTRAL
ROCKIES. THERE ARE SIGNIFICANT DISAGREEMENTS BETWEEN MODELS ON THE
TRACK AND TIMING OF THIS LOW AND THE SHORTWAVES...BUT THE GFS AND
ECMWF DO AGREE FAIRLY WELL ON A TAP OF SUBTROPICAL MOISTURE IN
STRENGTHENING SW FLOW ALOFT REACHING SW AREAS SUNDAY AND MUCH OF
CENTRAL AND WESTERN NM MONDAY.
A ROLLER COASTER OF TEMPERATURES IS EXPECTED THROUGH THE WEEKEND.
HIGH TEMPERATURES WILL WARM A FEW TO 5 DEGREES THURSDAY...THEN FALL
WITH THE BACK DOOR COLD FRONT FRIDAY. FALLING TEMPERATURES WILL
CONTINUE IN THE WEST THROUGH SATURDAY...WHILE EASTERN READINGS BEGIN
TO REBOUND. HIGH TEMPS SHOULD THEN WARM SUNDAY AS THE CENTER OF HIGH
PRESSURE DRAWS NEAR...THEN BEGIN TO FALL IN THE WEST AGAIN MONDAY AS
BETTER MOISTURE ARRIVES. MINIMUM HUMIDITIES SHOULD FALL A FEW TO 22
PERCENT ON SUNDAY BEFORE BEGINNING TO REBOUND IN THE WEST ON MONDAY.
HIGH HAINES VALUES IN THE 5 TO 6 RANGE ARE EXPECTED OVER NORTHWEST
AND NORTH CENTRAL AREAS THURSDAY...THEN OVER NW AND WEST CENTRAL
AREAS FRIDAY. EXTREME VALUES SHOULD ABATE EAST OF THE CONTINENTAL
DIVIDE WITH THE ARRIVAL OF BETTER MOISTURE ON FRIDAY NIGHT AND
SATURDAY...ONLY TO OVERSPREAD MOST LOCATIONS ALONG AND NORTH OF
INTERSTATE 40 ON SUNDAY. NORTHEAST AREAS MAY CONTINUE TO BE
AFFLICTED WITH HIGH HAINES ON MONDAY.
POCKETS OF POOR VENTILATION WILL IMPACT WEST CENTRAL AREAS
WEDNESDAY...THEN NORTH CENTRAL...CENTRAL AND SOUTHWEST AREAS
THURSDAY. POCKETS OF POOR VENTILATION MAY LINGER INTO FRIDAY WEST
OF THE CONTINENTAL DIVIDE AND OVER THE SANGRE DE CRISTOS...BUT
VENTILATION LOOKS TO IMPROVE MOST PLACES SATURDAY AND ESPECIALLY
SUNDAY. RATES SHOULD THEN STAY GOOD TO EXCELLENT MONDAY.
44
&&
.AVIATION...
18Z TAF CYCLE
TRUSTED MESOSCALE MODELS DEPICT SLOW MOVING -SHRA/-TS FAVORING
THE CENTRAL MT CHAIN AND ADJACENT E SLOPES...AS WELL AS NEW
MEXICOS SOUTHERN HIGH TERRAIN TODAY. MOST OF THE ACTIVITY WILL
DRIFT TO THE SE AROUND 5 TO 15 MPH...WHICH SHOULD EVENTUALLY TRACK
CELLS NEAR KTCC AND KROW. MODELS ALSO SUGGEST A FEW CELLS WILL POP
UP NEAR KSAF...KABQ...KAEG AND KGUP...THOUGH TS PROBABILITIES
WERE LOW ENOUGH TO USE VCSH RATHER THAN VCTS IN THESE TAFS. A FEW
ISOLD CELLS COULD LINGER INTO THE LATE NIGHT HOURS MAINLY ALONG
AND S OF HWY 60. A MIXTURE OF WET AND DRY MICROBURSTS ARE EXPECTED
TODAY WITH LOCALIZED AND ERRATIC WIND GUSTS NEAR 45 KT.
44
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 52 90 52 89 / 0 0 0 5
DULCE........................... 36 83 37 82 / 10 10 5 5
CUBA............................ 46 81 46 78 / 10 5 5 5
GALLUP.......................... 46 87 46 87 / 5 5 0 5
EL MORRO........................ 43 81 43 80 / 10 10 5 10
GRANTS.......................... 45 86 44 83 / 10 10 5 5
QUEMADO......................... 53 80 50 82 / 20 20 20 20
GLENWOOD........................ 56 77 54 83 / 30 30 30 20
CHAMA........................... 42 76 43 75 / 10 10 10 10
LOS ALAMOS...................... 58 81 58 79 / 10 10 5 10
PECOS........................... 55 78 54 73 / 20 10 10 30
CERRO/QUESTA.................... 51 78 50 75 / 20 20 10 30
RED RIVER....................... 38 72 39 66 / 20 20 10 40
ANGEL FIRE...................... 49 68 50 62 / 20 30 20 40
TAOS............................ 44 82 42 78 / 20 10 10 10
MORA............................ 50 75 51 68 / 30 30 20 30
ESPANOLA........................ 50 87 50 85 / 10 5 5 10
SANTA FE........................ 58 81 58 77 / 10 10 5 10
SANTA FE AIRPORT................ 54 87 55 83 / 10 10 5 10
ALBUQUERQUE FOOTHILLS........... 61 87 59 83 / 10 5 5 5
ALBUQUERQUE HEIGHTS............. 64 90 62 86 / 10 5 5 5
ALBUQUERQUE VALLEY.............. 59 91 58 88 / 10 5 0 5
ALBUQUERQUE WEST MESA........... 63 92 60 88 / 10 0 0 5
LOS LUNAS....................... 56 91 56 89 / 10 5 5 5
RIO RANCHO...................... 61 91 59 87 / 10 0 0 5
SOCORRO......................... 62 90 59 89 / 30 20 10 20
SANDIA PARK/CEDAR CREST......... 55 84 55 79 / 20 10 10 30
TIJERAS......................... 58 86 55 81 / 20 5 5 10
MORIARTY/ESTANCIA............... 49 85 49 81 / 20 10 10 30
CLINES CORNERS.................. 55 82 55 74 / 30 10 10 30
GRAN QUIVIRA.................... 58 81 55 78 / 40 20 20 30
CARRIZOZO....................... 62 84 59 83 / 40 30 20 20
RUIDOSO......................... 57 76 55 75 / 50 50 40 40
CAPULIN......................... 54 80 53 64 / 10 20 30 30
RATON........................... 49 87 51 74 / 10 20 20 30
SPRINGER........................ 51 86 52 74 / 10 10 20 30
LAS VEGAS....................... 50 83 49 74 / 30 30 20 30
CLAYTON......................... 59 88 58 70 / 10 10 30 30
ROY............................. 57 85 52 70 / 10 10 20 30
CONCHAS......................... 64 92 62 80 / 10 10 20 30
SANTA ROSA...................... 62 90 61 81 / 20 10 10 30
TUCUMCARI....................... 64 93 61 77 / 10 10 20 30
CLOVIS.......................... 63 89 61 80 / 20 10 10 30
PORTALES........................ 66 88 63 82 / 20 10 10 30
FORT SUMNER..................... 64 89 62 80 / 20 10 10 30
ROSWELL......................... 68 93 65 91 / 30 10 10 30
PICACHO......................... 62 86 60 83 / 30 20 20 30
ELK............................. 61 76 58 76 / 40 30 30 30
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
316 PM EDT WED SEP 9 2015
.SYNOPSIS...
LATE SUMMER WEATHER WILL BE IN PLACE TODAY WITH HIGH HUMIDITY AND
SCATTERED THUNDERSTORMS. CLOUDS AND RAIN CHANCES REMAIN THROUGH
LATE IN THE WEEK WITH THE SLOW APPROACH OF A COLD FRONT. THIS
FRONT MAY STALL IN THE AREA UNTIL EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 3 PM WEDNESDAY...ISOLATED SHOWERS AND THUNDERSTORMS CONTINUE
GENERALLY IN THE REGION THE HRRR HAD INDICATED BUT NOT THE COVERAGE
IT WAS ADVERTISING. THE CONVECTION IS GENERALLY EAST OF A LINE FROM
LUMBERTON TO MYRTLE BEACH TO GEORGETOWN.
OVERNIGHT IT IS VERY HARD TO DETECT A SIGNIFICANT SHORTWAVE AS WE
HAD LAST NIGHT. THE MODELS ARE SHOWING THE SURFACE LOW PRESSURE AREA
DEPICTED BY THE MODELS WEAKENING AS IT DRIFTS NORTHWARD. THUS WILL
PROVIDE LITTLE FORCING SO HAVE KEPT ONLY ISOLATED CONVECTION FOR THE
OVERNIGHT PERIOD. FOR LOW TEMPERATURES ARE EXPECTED TO FALL INTO THE
LOWER TO MIDDLE 70S.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 PM WEDNESDAY...A WARM AND MOIST AIRMASS WILL REMAIN IN
PLACE OVER THE EASTERN CAROLINAS IN ADVANCE OF A SLOW-MOVING COLD
FRONT...WHICH WILL BE POSITIONED TO THE NW OVER THE APPALACHIANS
BY THE END OF THE SHORT TERM. THIS FRONT WILL BE PRECEDED BY A
PRE-FRONTAL TROUGH...WHILE AT THE MID LEVELS AN H/5 TROUGH DEEPENS
OVER EASTERN CONUS. AMPLE MOISTURE AND A SERIES OF UPPER
DISTURBANCES ROUNDING THE BASE OF THE H/5 TROUGH MEANS CHANCE POPS
WILL REMAIN IN PLAY FOR BOTH THURSDAY AND FRIDAY. BEST CHANCES FOR
CONVECTION WILL ACTUALLY BE ON FRIDAY...WHEN GUIDANCE SUGGESTS WE
WILL HAVE THE DEEPEST MOISTURE AND WHEN THE PREFRONTAL TROUGH
IMPINGES UPON THE CWA.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 3 PM WEDNESDAY...LOOKS LIKE UNSETTLED WEATHER WILL EXIST
THROUGH MUCH OF THE WEEKEND AS LINGERING FRONT/LOW PRESSURE TROUGH
REMAINS OVER INLAND CAROLINAS THROUGH SATURDAY INTO EARLY SUNDAY.
WINDS WILL BASICALLY STAY SW THROUGH THE COLUMN SAT THROUGH SUNDAY
MORNING WITH DEEP LAYER MOISTURE AND MINOR PERTURBATIONS RIDING
AROUND THE DEEP LONG WAVE MID TO UPPER LEVEL DIGGING DOWN FROM THE
GREAT LAKES TO THE GULF COAST. MAY SEE A DRY PUNCH THROUGH SATURDAY
WITH A DROP IN PCP WATER VALUES DOWN TO LESS THAN 1.5
INCHES...MAINLY INLAND EARLIER IN THE DAY. PCP WATER VALUES UP NEAR
2 INCHES ALONG THE CAPE FEAR COAST WILL SEE SOME DRYING OUT BUT
OVERALL EXPECT A MOIST AND UNSTABLE AIR MASS WITH INCREASED
POTENTIAL FOR SHWRS AND TSTMS THROUGH SATURDAY INTO EARLY SUNDAY
BEFORE NEXT COLD FRONT MOVES IN. ECMWF REMAINS SLIGHTLY DRIER AS
POSITION OF UPPER TROUGH FARTHER EAST THROUGH SATURDAY BUT WILL HAVE
TO SEE WHAT NEW MODEL RUN BRINGS.
THIS MID TO UPPER TROUGH WILL PUSH A COLD FRONT EAST THROUGH THE
CAROLINAS ON SUNDAY WITH PLENTY OF DRY AIR BEHIND IT. THIS RUSH OF
DRY AND RELATIVELY COOLER AIR SHOULD MAKE ITS WAY IN THROUGH SUN
AFTN AS PCP WATER VALUES DROP TO LESS THAN AN INCH WITH AN
ADDITIONAL DROP DOWN TO LESS THAN A HALF INCH BY MON INTO TUES. 850
TEMPS SHOW A DROP FROM NEAR 17C SAT EVENING TO 11C BY MON MORNING.
THEREFORE EXPECT TEMPS DOWN BELOW NORMAL...CLOSER TO 80 FOR HIGHS
AND DEWPOINT TEMPS DOWN BELOW 50 IN SPOTS INLAND AND MID 50S MOST
PLACES MON INTO TUES. THIS VERY DRY AIR IN PLACE WILL CREATE LARGER
DIURNAL RANGES WITH LOW TEMPS TO DROP INTO THE 50S AND 60S ALONG THE
COAST SUN NIGHT AND MON NIGHT.
OVERALL EXPECT UNSETTLED WEATHER WITH PLENTY OF CLOUDS AND INCREASED
POTENTIAL FOR SHWRS/TSTMS IN A MORE HUMID AIR MASS AHEAD OF COLD
FRONT THROUGH EARLY SUNDAY. THEN MUCH LESS HUMID WEATHER WITH COOLER
NIGHT AND WARMER EVE THROUGH TUES AS DRY HIGH PRESSURE DOMINATES OUR
WEATHER. BY LATE NEXT WED WINDS WILL COME AROUND BECOMING MORE ON
SHORE WITH A SLIGHT INCREASE IN MOISTURE BUT ANY PCP SHOULD HOLD OFF
UNTIL WED NIGHT OR THURS.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 18Z...THE CONVERGENT BAND OF CONVECTION SPOOLING OFF OF A
LOW IN GEORGIA HAS MOVED THROUGH THE CWA...HOWEVER THE ATMOSPHERE
EXPECTED TO RELOAD WITH INSTABILITY BY TAF TIME. EXPECT THE
RESULTANT BOUNDARY TO BE THE FOCUS FOR CONVECTION NEAR
SHORE...WITH ISOLATED ACTIVITY INLAND. BRIEF IFR POSSIBLE...BUT
MVFR IN SHOWERS FOR THE MOST PART. MOST OF THE ACTIVITY WILL
DIMINISH BY LATE AFTERNOON.
OVERNIGHT...SOME LIGHT FOG COMBINED WITH MVFR/NEAR IFR CEILINGS
TOWARD MORNING WITH CONTINUED LOW LEVEL MOISTURE. COULD NOT RULE OUT
A SHOWER BASED ON THE NAM...HOWEVER IT HAS BEEN OVERDOING IT THROUGH
THE OVERNIGHT HOURS.
THURSDAY...CONTINUED HOT AND HUMID WITH AFTERNOON CONVECTION POSSIBLE.
SOUTHWEST GRADIENT WILL BE STRONGER THAN TODAY...BECOMING GUSTY
IN THE AFTERNOON.
EXTENDED OUTLOOK...POSSIBLE NUMEROUS STORMS FRIDAY AND SATURDAY.
STORMS ENDING SUNDAY MORNING WITH COOLER CONDITIONS INTO MONDAY.&&
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 3 PM WEDNESDAY...SOUTH TO SOUTH-SOUTHWEST WINDS OF 10 TO 15
KTS WITH SEAS OF 2 TO 3 FEET ARE CURRENTLY OCCURRING OVER THE
COASTAL WATERS. AS HIGH PRESSURE WEAKENS SLOWLY OVERNIGHT AND THE
INFLUENCE OF A COLD FRONT WEST OF THE CAROLINAS WILL CAUSE THE WINDS
TO BECOME MORE SOUTHWESTERLY OVERNIGHT. WINDS SPEEDS ARE FORECAST TO
RUN AROUND 15 KNOT. SEAS WILL RUN AROUND 3 FEET WITH A FEW 4 FOOTS
IN THE SOUTHEAST PORTIONS OF THE LITTLE RIVER TO CAPE FEAR MARINE
ZONE.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 PM WEDNESDAY...WINDS WILL REMAIN SOUTHWESTERLY THROUGH THE
PERIOD AS A COLD FRONT SLOWLY ADVANCES UPON THE WATERS. THE FRONT
WILL NOT MAKE IT TO THE WATERS DURING THE NEAR TERM...BUT WE WILL
LIKELY SEE A GRADUAL TIGHTENING OF THE GRADIENT...WHICH WILL
INCREASE WINDS FROM A GENERAL 10 TO 15 KT RANGE TO AROUND 15 KTS
OR SO BY FRIDAY NIGHT. SEAS WILL LIKEWISE INCREASE...WITH 3 TO 4
FT SEAS DEVELOPING FRIDAY/FRIDAY NIGHT.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3 PM WEDNESDAY...DECENT SW FLOW THROUGH MUCH OF THE WEEKEND
AS TROUGH OF LOW PRESSURE REMAINS JUST INLAND OF COAST. DECENT
GRADIENT THROUGH SAT MORNING WITH SW WINDS UP TO 15 KTS WILL
DIMINISH THROUGH LATE SATURDAY INTO SUNDAY AS WINDS BEGIN TO VEER
AROUND AS COLD FRONT APPROACHES FROM THE WEST. LATEST WNA SHOWS WIND
SHIFT TO W-NW BY LATE SUNDAY AS COLD FRONT CROSSES THE WATERS.
PERSISTENT SW WINDS WILL PUSH SEAS UP TO 3 TO 5 FT THROUGH SAT AND
THEN DIMINISHING WITH OFF SHORE FLOW THROUGH LATE SUNDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...REK
NEAR TERM...DRH
SHORT TERM...REK/MBB
LONG TERM...RGZ
AVIATION...DL
MARINE...REK/RGZ/DRH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
138 PM EDT WED SEP 9 2015
.SYNOPSIS...
SUMMER LIKE HEAT WILL BE IN PLACE TODAY WITH SCATTERED
THUNDERSTORMS...MOST NUMEROUS ALONG THE COAST. CLOUDS AND RAIN
CHANCES THEN INCREASE LATE IN THE WEEK WITH THE SLOW APPROACH OF A
COLD FRONT. THIS BOUNDARY MAY NOT PUSH THROUGH UNTIL MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1 PM WEDNESDAY...ISOLATED SHOWERS AND THUNDERSTORMS CONTINUE
BEHIND THIS MORNINGS SHORTWAVE. MOST OF THIS AFTERNOONS CONVECTION
IS EAST OF A LINE FROM LUMBERTON TO MYRTLE BEACH TO GEORGETOWN.
THE 15/16 HRRR CONTINUE TO SHOW CONVECTION WANING LATER THIS
AFTERNOON AND ONLY ISOLATED CONVECTION AFTER SUNSET.
OVERNIGHT IT IS VERY HARD TO DETECT A SIGNIFICANT SHORTWAVE AS WAS
EARLY THOUGHT. THE LOW PRESSURE AREA IS DEPICTED BY THE MODELS OF
WEAKENING AS IT DRIFTS NORTHWARD. THUS WILL LITTLE FORCING HAVE
KEPT ONLY ISOLATED FOR THE OVERNIGHT PERIOD. FOR LOW TEMPERATURES
AREA EXPECTED TO FALL INTO THE LOWER TO MIDDLE 70S.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY... PREFRONTAL TROUGH MOVES INTO THE CAROLINAS
AND STALLS ON THURSDAY. AHEAD OF THIS FEATURE THERE SHOULD BE AMPLE
MOISTURE FOR AT LEAST SCATTERED CONVECTIVE COVERAGE. MID LEVEL
FORCING IN THE FORM OF VORT MAXES COME LATE IN THE DAY AND AT NIGHT
PREVENTING THE NORMAL DIURNAL DYING OFF OF RADAR COVERAGE EVEN
THOUGH DEEP CONVECTION MAY BE HARDER TO COME BY DUE TO THE DECREASE
IN INSTABILITY. THIS BOUNDARY WEAKENS AND MOVES OFFSHORE BY FRIDAY
AND WAS PREVIOUSLY TO BE REPLACED BY A LEGITIMATE COLD FRONT. THIS
FRONT NOW APPEARS SLOWER LEAVING NOT MUCH IN THE WAY OF SURFACE
FEATURES IN PLACE LOCALLY. FURTHER COMPLICATING FRIDAY FORECAST IS
THE DIFFERENCE IN TIMING AMONGST MODELS WITH RESPECT TO SOME MID
LEVEL IMPULSES. IN THE END DID NOT MAKE MUCH CHANGE AND WILL ONCE
AGAIN CARRY CHANCE POPS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY... IMPRESSIVELY DEEP UPPER TROUGH DRIVES COLD
FRONT INTO THE COASTAL PLAIN ON SATURDAY. BEING ALIGNED WITH THE FLOW
ALOFT IT WILL STALL ON SUNDAY. SATURDAY OFFERS THE DEEPEST MOISTURE
AND WILL LIKELY PAN OUT BEING A VERY UNSETTLED DAY WITH PERHAPS
NUMEROUS SHOWERS AND IF THE DIURNAL TIMING IS RIGHT STRONGER
THUNDERSTORMS. MODELS AT SOME ODDS REGARDING THE DEPTH AND TILT OF
THE UPPER WAVE AND UNTIL IT ENTERS THE UPPER AIR NETWORK ITS HARD TO
SPECULATE WHICH IS CORRECT. ON SUNDAY THE DEEP MOISTURE GETS SHUNTED
OFFSHORE BUT SOME LOW LEVEL MOISTURE ALONG THE BOUNDARY WILL STILL
CALL FOR SOME LOW RAIN CHANCES MAINLY ALONG THE COAST. COOLER AND
DRYER AIR NOW APPEARS TO ARRIVE FASTER AND SHOULD BE ADVECTING IN
MODERATELY STRONGLY BY MONDAY. COOLER WEATHER WILL LAST INTO TUESDAY
AS THE CENTER OF THE LARGE HIGH BUILDS TO OUR NORTH.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 18Z...THE CONVERGENT BAND OF CONVECTION SPOOLING OFF OF A
LOW IN GEORGIA HAS MOVED THROUGH THE CWA...HOWEVER THE ATMOSPHERE
EXPECTED TO RELOAD WITH INSTABILITY BY TAF TIME. EXPECT THE
RESULTANT BOUNDARY TO BE THE FOCUS FOR CONVECTION NEAR
SHORE...WITH ISOLATED ACTIVITY INLAND. BRIEF IFR POSSIBLE...BUT
MVFR IN SHOWERS FOR THE MOST PART. MOST OF THE ACTIVITY WILL
DIMINISH BY LATE AFTERNOON.
OVERNIGHT...SOME LIGHT FOG COMBINED WITH MVFR/NEAR IFR CEILINGS
TOWARD MORNING WITH CONTINUED LOW LEVEL MOISTURE. COULD NOT RULE OUT
A SHOWER BASED ON THE NAM...HOWEVER IT HAS BEEN OVERDOING IT THROUGH
THE OVERNIGHT HOURS.
THURSDAY...CONTINUED HOT AND HUMID WITH AFTERNOON CONVECTION POSSIBLE.
SOUTHWEST GRADIENT WILL BE STRONGER THAN TODAY...BECOMING GUSTY
IN THE AFTERNOON.
EXTENDED OUTLOOK...POSSIBLE NUMEROUS STORMS FRIDAY AND SATURDAY.
STORMS ENDING SUNDAY MORNING WITH COOLER CONDITIONS INTO MONDAY.&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 130 PM WEDNESDAY...SOUTH TO SOUTH-SOUTHWEST WINDS OF 10 TO
15 KTS WITH SEAS OF 2 TO 3 FEET CURRENTLY ARE OCCURRING OVER THE
COASTAL WATERS. HIGH PRESSURE WILL SLOWLY LESSEN ITS IMPACT BY
THIS EVENING AS A COLD FRONT WELL TO THE WEST MOVES CLOSER TO THE
CAROLINAS. WINDS ARE EXPECTED TO SHIFT MORE TO THE SOUTHWEST AND
INCREASE TO 10 TO 15 KNOTS. SEAS WILL GRADUALLY INCREASE TO 3
FEET.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY... A PREFRONTAL TROUGH WILL BOOST WIND AND
SEAS ON THURSDAY. WE ARE NOT ANTICIPATING HEADLINES OR ADVISORIES,
BUT ITS BEEN FAIRLY QUIET SO THURSDAY WILL BE MORE UNSETTLED THAN
THE PAST FEW DAYS WITH THE ADVENT OF SOME 4 FT SEAS. ON FRIDAY
THIS BOUNDARY MOVES OFFSHORE AND WEAKENS IF NOT DISSIPATE
ALTOGETHER. THE 20KT GUSTINESS SHOULD DROP OUT OF THE FORECAST AS
WILL ANY 4 FT WAVES. A COLD FRONT WILL ALSO BE APPROACHING FROM
THE NW ON FRIDAY BUT IT NOW LOOKS SLOWER THAN PREVIOUSLY FORECAST.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3 AM WEDNESDAY... WITH THE SLOWER ARRIVAL OF COLD FRONT ON
SATURDAY THE AREA MAY STAY IN AN INCREASED GRADIENT PRE-FRONTAL FLOW
REGIME. AS SUCH WIND SPEEDS MAY NEED TO BE RE-EVALUATED AND RAISED
ESPECIALLY AS SOME HIGHER MID LEVEL WINDS MAY BE IMPINGING UPON THE
AREA. THE UPPER WAVE DRIVING THIS SYSTEM IS FAR FROM BEING SAMPLED
BY THE UPPER AIR NETWORK HOWEVER AND SO NO LARGE CHANGES WILL BE
MADE AT THIS TIME. SHOULD THINGS KEEP SLOWING DOWN THEN A SW WIND
WILL REMAIN ON SUNDAY AS THE BOUNDARY EITHER STALLS ALONG THE COAST
OR PERHAPS JUST INLAND. EITHER WAY THE STRONGER GRADIENT WILL HAVE
PUSHED FURTHER OFFSHORE AND THE POSSIBILITY OF HIGHER WINDS AND SEAS
THAN THE CURRENT FORECAST ALONG WITH IT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DRH
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...DL
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
658 PM EDT WED SEP 9 2015
.SYNOPSIS...
A COLD FRONT OVER NORTHERN OHIO WILL CONTINUE TO MOVE SOUTHEAST
AWAY FROM THE LOCAL AREA TONIGHT. THE FRONT IS EXPECTED TO
EVENTUALLY STALL NEAR THE OHIO RIVER ON THURSDAY MORNING. WEAK
HIGH PRESSURE WILL BUILD OVER THE REGION TOMORROW AND TOMORROW
NIGHT. ANOTHER COLD FRONT WILL FOLLOW ON FRIDAY WITH A POTENT
UPPER AIR DISTURBANCE EXPECTED TO IMPACT THE LOCAL AREA OVER THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
SHOWERS HAVE DIMINISHED ACROSS MOST OF THE AREA EXCEPT A FEW
SPRINKLES THAT MOVED INTO SOUTHERN HANCOCK COUNTY. MOST AREAS WILL
BE DRY FOR THE REMAINDER OF THE NIGHT BUT LEFT A LOW 20-30 POP IN
ACROSS THE SOUTHERN COUNTIES AS SOME SHORTWAVE ENERGY CONTINUES TO
STREAM NORTHEAST. LOW LEVEL DRY AIR SHOULD WIN OUT ACROSS THE
NORTHERN COUNTIES AND REMOVED ANY REMAINING CHANCE OF RAIN FROM
THE FORECAST. LOW CLOUDS HAVE ALREADY SCATTERED OUT ACROSS NW OHIO SO
ANY PRECIPITATION REACHING THE GROUND WILL BE VERY LIGHT AS IT
FALLS OUT OF A MID-CLOUD DECK.
PREVIOUS DISCUSSION...
AS FEARED...LITTLE PRECIP HAS DEVELOPED THIS AFTERNOON. SOME
SCATTERED SHOWERS REMAIN OVER THE EASTERN END OF THE AREA. MOST OF
THE GUIDANCE INCLUDING THE LATEST RUC AND HRRR SHOW THE
POSSIBILITY OF NEW DEVELOPMENT THROUGH EARLY EVENING FROM ABOUT
I-71 EAST. THIS SEEM PLAUSIBLE GIVEN THE SHOWERS OVER INDIANA AND
SW OHIO SO WILL KEEP A SMALL MENTION FOR A FEW HOURS. BY MIDNIGHT
ALL BUT THE SE END OF THE AREA SHOULD BE DRY. THE SURFACE FRONT
WILL EVENTUALLY STALL AND THE THREAT FOR SHOWERS ACROSS THE SE TIP
OF THE AREA COULD PERSIST INTO THURSDAY MORNING. THE NEAREST
CLEARING IS STILL BACK BY CHICAGO SO THAT WILL TAKE SOME TO REACH
THE LOCAL AREA AS WELL. DO THINK THAT THAT ABOUT THE NW 1/3 TO
1/2 OF THE AREA WILL BECOME PARTLY CLOUDY BY MORNING. THIS WILL
RESULT IN A DECENT TEMPERATURE GRADIENT ACROSS THE AREA WITH LOW
60S IN THE SE AND READINGS WELL DOWN INTO THE 50S IN THE NW.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY NIGHT/...
JUST MINOR ADJUSTMENTS TO THE SHORT TERM TODAY AS THE PREVIOUS
PACKAGE WAS ON THE RIGHT TRACK. THURSDAY AND THURSDAY NIGHT WILL
BE DRY. ANOTHER COLD FRONT IS STILL ON TRACK FOR FRIDAY. VERY
LITTLE IF ANY PRECIP IS EXPECTED BEFORE 12Z. WILL END UP GOING
WITH A FEW HOURS OF LIKELY MOST AREAS. UNFORTUNATELY THE BEST
WINDOW FOR PRECIP IN THE EAST WILL BE FRIDAY AFTERNOON AND
EVENING. THERE WILL BE A DISTINCT AIRMASS CHANGE BEHIND THIS FRONT
WITH THE UNSEASONABLY COOL AIR SETTLING OVER THE AREA OVER THE
WEEKEND. AS A RESULT...INSTABILITY SHOWERS HELPED ALONG BY LAKE
ERIE CAN BE EXPECTED BOTH SATURDAY AND SUNDAY. BY 12Z SUNDAY 500
MB TEMPS WILL BE ON THEIR WAY TO NEG 20 OR COLDER WHICH WILL GIVE
LAKE TO 500MB TEMP DIFFERENCES OF 45 DEGREES OR GREATER. THIS
MEANS THUNDER WILL BE A GOOD BET DOWNWIND OF THE LAKE AND HAVE
BUMPED PRECIP CHANCES TO LIKELY IN FAR NE OH AND NW PA FOR
SATURDAY NIGHT. HAVE CONTINUED THE RECENT TREND OF LOWERING HIGH
TEMPS OVER THE WEEKEND. THERE COULD BE A FEW AREAS THAT FAIL TO
GET OUT OF THE 50S FOR HIGHS ON SUNDAY.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AN UPPER LEVEL LOW WILL BE MOVING OFF TO THE EAST ON SUNDAY WILL
BRING COLDER TEMPERATURES 10-15 DEGREES BELOW AVERAGE AND
NORTHWESTERLY FLOW TO NORTHERN OHIO AND NORTHEAST PA. THIS NORTHWEST
FLOW OFF OF LAKE ERIE...PLUS 850 MB TEMPERATURES OF 6-8C...AND WARM
LAKE WATER TEMPERATURES AROUND 70F (A TEMPERATURE DIFFERENCE OF
AROUND 25 DEGREES FAHRENHEIT) WILL ALLOW FOR SOME SIGNIFICANT
LAKE EFFECT RAIN TO DEVELOP OVER THE AREA ON SUNDAY INTO THE EARLY
PART OF MONDAY. IN SHORT...SUNDAY WILL BE MORE REPRESENTATIVE OF A
COLD AND RAINY NOVEMBER DAY THAN THE GLIMPSE OF JULY THAT WE HAD
OVER LABOR DAY WEEKEND.
LATE ON MONDAY...SOME UPPER LEVEL RIDGING WILL MOVE IN ALONG WITH A
SURFACE HIGH PRESSURE. WINDS WILL SHIFT TO COME FROM THE SOUTH AND
WILL WARM TEMPERATURES CLOSER TO CLIMO AND DRY THE AREA OUT FROM WET
WEATHER OVER THE WEEKEND. HIGH PRESSURE LOOKS TO BE IN PLACE THROUGH
A MAJORITY OF WEDNESDAY ALLOWING FOR A COUPLE OF DRY...TYPICAL MID-
SEPTEMBER DAYS IN NORTHERN OHIO AND NORTHWEST PA.
MODELS CURRENTLY DEPICT A COLD FRONT BEGINNING TO APPROACH THE AREA
BY THURSDAY MORNING...WHICH COULD BRING SOME WET WEATHER FOR THE END
OF NEXT WEEK. STILL A LITTLE FAR OUT TO TELL WHAT COULD HAPPEN WITH
THIS SYSTEM AS IT APPROACHES THE EASTERN GREAT LAKES.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
COLD FRONT IS NOW EAST OF THE TAF SITES WITH A FEW SCATTERED
SHOWERS AND MAYBE A RUMBLE OF THUNDER LAGGING BEHIND. WIDESPREAD
MVFR CONDITIONS WITH CEILINGS ON EITHER SIDE OF 2K FEET WILL BE
COMMON THROUGH THE REMAINDER OF THE AFTERNOON. THE FRONTS EASTWARD
PROGRESS SLOWS TONIGHT AND SHOWERS MAY CONTINUE ACROSS CAK/YNG
INTO THE NIGHT. QUESTIONS WITH WHAT CEILINGS MAY DO OVERNIGHT.
FORECAST SOUNDINGS AND OBSERVED SOUNDINGS SHOW THE LOWER LEVEL
MOISTURE RESIDING BELOW MID LEVEL DRYING. GUIDANCE IS SUGGESTING
VFR CONDITIONS OVERNIGHT...BUT WITH FRONT LINGERING TO OUR
SOUTHEAST AND A NORTHEAST FLOW OFF OF THE LAKE...THINK AT LEAST
KEEPING MVFR CEILINGS AROUND WOULD BE THE WAY TO GO. WINDS HAVE
SHIFTED TO THE WEST- NORTHWEST TO NORTHWEST AND WILL CONTINUE TO
ROTATE AROUND TO NORTHEAST THIS EVENING AND CONTINUE FROM THAT
DIRECTION THURSDAY.
OUTLOOK...NON VFR STARTING LATER FRIDAY AND CONTINUING THROUGH
THE WEEKEND...ESPECIALLY FOR NE OH AND NW PA.
&&
.MARINE...
HAVE CANCELED THE SMALL CRAFT ADVISORY. LATEST GUIDANCE
AND ANALYSIS OF CURRENT CONDITIONS LEADS TOWARD 2 TO OCCASIONALLY 4
FEET OVERNIGHT. THE GRADIENT IS NOT THAT TIGHT AND COLD AIR
ADVECTION NOT STRONG. NORTH FLOW COMES AROUND TO THE NORTHEAST THIS
EVENING AND WILL BE SITTING AT 10 TO 15 KNOTS SUSTAINED. HIGH
PRESSURE WILL STAY NORTH OF THE LAKE ON THURSDAY AND GET SQUEEZED
OUT BY AN APPROACHING COLD FRONT FROM THE NORTHWEST ON FRIDAY. THIS
FRONT WILL HAVE THE POTENTIAL TO CHURN UP THE LAKE WITH STRONG COLD
AIR ADVECTION COMMENCING FRIDAY NIGHT OR SATURDAY MORNING. SMALL
CRAFT ADVISORIES A POSSIBILITY THIS WEEKEND. UPPER LOW STAYS IN THE
VICINITY AND IT WILL BE A COOL AND SHOWERY WEEKEND. WINDS ARE NOT
TOO STRONG ALOFT AND WATERSPOUTS MAY BE POSSIBLE THIS WEEKEND TOO.
HIGH PRESSURE BUILDS ACROSS THE LOWER OHIO VALLEY MONDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KUBINA
NEAR TERM...KUBINA
SHORT TERM...KUBINA
LONG TERM...SEFCOVIC
AVIATION...OUDEMAN
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
345 PM EDT WED SEP 9 2015
.SYNOPSIS...
A COLD FRONT OVER NORTHERN OHIO WILL CONTINUE TO MOVE SOUTHEAST
AWAY FROM THE LOCAL AREA TONIGHT. THE FRONT IS EXPECTED TO
EVENTUALLY STALL NEAR THE OHIO RIVER ON THURSDAY MORNING. WEAK
HIGH PRESSURE WILL BUILD OVER THE REGION TOMORROW AND TOMORROW
NIGHT. ANOTHER COLD FRONT WILL FOLLOW ON FRIDAY WITH A POTENT
UPPER AIR DISTURBANCE EXPECTED TO IMPACT THE LOCAL AREA OVER THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS FEARED...LITTLE PRECIP HAS DEVELOPED THIS AFTERNOON. SOME
SCATTERED SHOWERS REMAIN OVER THE EASTERN END OF THE AREA. MOST OF
THE GUIDANCE INCLUDING THE LATEST RUC AND HRRR SHOW THE
POSSIBILITY OF NEW DEVELOPMENT THROUGH EARLY EVENING FROM ABOUT
I-71 EAST. THIS SEEM PLAUSIBLE GIVEN THE SHOWERS OVER INDIANA AND
SW OHIO SO WILL KEEP A SMALL MENTION FOR A FEW HOURS. BY MIDNIGHT
ALL BUT THE SE END OF THE AREA SHOULD BE DRY. THE SURFACE FRONT
WILL EVENTUALLY STALL AND THE THREAT FOR SHOWERS ACROSS THE SE TIP
OF THE AREA COULD PERSIST INTO THURSDAY MORNING. THE NEAREST
CLEARING IS STILL BACK BY CHICAGO SO THAT WILL TAKE SOME TO REACH
THE LOCAL AREA AS WELL. DO THINK THAT THAT ABOUT THE NW 1/3 TO
1/2 OF THE AREA WILL BECOME PARTLY CLOUDY BY MORNING. THIS WILL
RESULT IN A DECENT TEMPERATURE GRADIENT ACROSS THE AREA WITH LOW
60S IN THE SE AND READINGS WELL DOWN INTO THE 50S IN THE NW.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY NIGHT/...
JUST MINOR ADJUSTMENTS TO THE SHORT TERM TODAY AS THE PREVIOUS
PACKAGE WAS ON THE RIGHT TRACK. THURSDAY AND THURSDAY NIGHT WILL
BE DRY. ANOTHER COLD FRONT IS STILL ON TRACK FOR FRIDAY. VERY
LITTLE IF ANY PRECIP IS EXPECTED BEFORE 12Z. WILL END UP GOING
WITH A FEW HOURS OF LIKELY MOST AREAS. UNFORTUNATELY THE BEST
WINDOW FOR PRECIP IN THE EAST WILL BE FRIDAY AFTERNOON AND
EVENING. THERE WILL BE A DISTINCT AIRMASS CHANGE BEHIND THIS FRONT
WITH THE UNSEASONABLY COOL AIR SETTLING OVER THE AREA OVER THE
WEEKEND. AS A RESULT...INSTABILITY SHOWERS HELPED ALONG BY LAKE
ERIE CAN BE EXPECTED BOTH SATURDAY AND SUNDAY. BY 12Z SUNDAY 500
MB TEMPS WILL BE ON THEIR WAY TO NEG 20 OR COLDER WHICH WILL GIVE
LAKE TO 500MB TEMP DIFFERENCES OF 45 DEGREES OR GREATER. THIS
MEANS THUNDER WILL BE A GOOD BET DOWNWIND OF THE LAKE AND HAVE
BUMPED PRECIP CHANCES TO LIKELY IN FAR NE OH AND NW PA FOR
SATURDAY NIGHT. HAVE CONTINUED THE RECENT TREND OF LOWERING HIGH
TEMPS OVER THE WEEKEND. THERE COULD BE A FEW AREAS THAT FAIL TO
GET OUT OF THE 50S FOR HIGHS ON SUNDAY.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AN UPPER LEVEL LOW WILL BE MOVING OFF TO THE EAST ON SUNDAY WILL
BRING COLDER TEMPERATURES 10-15 DEGREES BELOW AVERAGE AND
NORTHWESTERLY FLOW TO NORTHERN OHIO AND NORTHEAST PA. THIS NORTHWEST
FLOW OFF OF LAKE ERIE...PLUS 850 MB TEMPERATURES OF 6-8C...AND WARM
LAKE WATER TEMPERATURES AROUND 70F (A TEMPERATURE DIFFERENCE OF
AROUND 25 DEGREES FAHRENHEIT) WILL ALLOW FOR SOME SIGNIFICANT LAKE
EFFECT RAIN TO DEVELOP OVER THE AREA ON SUNDAY INTO THE EARLY PART
OF MONDAY. IN SHORT...SUNDAY WILL BE MORE REPRESENTATIVE OF A COLD
AND RAINY NOVEMBER DAY THAN THE GLIMPSE OF JULY THAT WE HAD OVER
LABOR DAY WEEKEND.
LATE ON MONDAY...SOME UPPER LEVEL RIDGING WILL MOVE IN ALONG WITH A
SURFACE HIGH PRESSURE. WINDS WILL SHIFT TO COME FROM THE SOUTH AND
WILL WARM TEMPERATURES CLOSER TO CLIMO AND DRY THE AREA OUT FROM WET
WEATHER OVER THE WEEKEND. HIGH PRESSURE LOOKS TO BE IN PLACE THROUGH
A MAJORITY OF WEDNESDAY ALLOWING FOR A COUPLE OF DRY...TYPICAL MID-
SEPTEMBER DAYS IN NORTHERN OHIO AND NORTHWEST PA.
MODELS CURRENTLY DEPICT A COLD FRONT BEGINNING TO APPROACH THE AREA
BY THURSDAY MORNING...WHICH COULD BRING SOME WET WEATHER FOR THE END
OF NEXT WEEK. STILL A LITTLE FAR OUT TO TELL WHAT COULD HAPPEN WITH
THIS SYSTEM AS IT APPROACHES THE EASTERN GREAT LAKES.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
COLD FRONT IS NOW EAST OF THE TAF SITES WITH A FEW SCATTERED
SHOWERS AND MAYBE A RUMBLE OF THUNDER LAGGING BEHIND. WIDESPREAD
MVFR CONDITIONS WITH CEILINGS ON EITHER SIDE OF 2K FEET WILL BE
COMMON THROUGH THE REMAINDER OF THE AFTERNOON. THE FRONTS EASTWARD
PROGRESS SLOWS TONIGHT AND SHOWERS MAY CONTINUE ACROSS CAK/YNG
INTO THE NIGHT. QUESTIONS WITH WHAT CEILINGS MAY DO OVERNIGHT.
FORECAST SOUNDINGS AND OBSERVED SOUNDINGS SHOW THE LOWER LEVEL
MOISTURE RESIDING BELOW MID LEVEL DRYING. GUIDANCE IS SUGGESTING
VFR CONDITIONS OVERNIGHT...BUT WITH FRONT LINGERING TO OUR
SOUTHEAST AND A NORTHEAST FLOW OFF OF THE LAKE...THINK AT LEAST
KEEPING MVFR CEILINGS AROUND WOULD BE THE WAY TO GO. WINDS HAVE
SHIFTED TO THE WEST- NORTHWEST TO NORTHWEST AND WILL CONTINUE TO
ROTATE AROUND TO NORTHEAST THIS EVENING AND CONTINUE FROM THAT
DIRECTION THURSDAY.
OUTLOOK...NON VFR STARTING LATER FRIDAY AND CONTINUING THROUGH
THE WEEKEND...ESPECIALLY FOR NE OH AND NW PA.
&&
.MARINE...
HAVE CANCELED THE SMALL CRAFT ADVISORY. LATEST GUIDANCE
AND ANALYSIS OF CURRENT CONDITIONS LEADS TOWARD 2 TO OCCASIONALLY 4
FEET OVERNIGHT. THE GRADIENT IS NOT THAT TIGHT AND COLD AIR
ADVECTION NOT STRONG. NORTH FLOW COMES AROUND TO THE NORTHEAST THIS
EVENING AND WILL BE SITTING AT 10 TO 15 KNOTS SUSTAINED. HIGH
PRESSURE WILL STAY NORTH OF THE LAKE ON THURSDAY AND GET SQUEEZED
OUT BY AN APPROACHING COLD FRONT FROM THE NORTHWEST ON FRIDAY. THIS
FRONT WILL HAVE THE POTENTIAL TO CHURN UP THE LAKE WITH STRONG COLD
AIR ADVECTION COMMENCING FRIDAY NIGHT OR SATURDAY MORNING. SMALL
CRAFT ADVISORIES A POSSIBILITY THIS WEEKEND. UPPER LOW STAYS IN THE
VICINITY AND IT WILL BE A COOL AND SHOWERY WEEKEND. WINDS ARE NOT
TOO STRONG ALOFT AND WATERSPOUTS MAY BE POSSIBLE THIS WEEKEND TOO.
HIGH PRESSURE BUILDS ACROSS THE LOWER OHIO VALLEY MONDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KUBINA
NEAR TERM...KUBINA
SHORT TERM...KUBINA
LONG TERM...SEFCOVIC
AVIATION...OUDEMAN
MARINE...OUDEMAN
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
1226 PM CDT WED SEP 9 2015
.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
&&
.AVIATION...VFR CONDITIONS. SEA BREEZE NOT QUITE ESTABLISHED
YET...AND MAY HAVE A TOUGH TIME WITH BREEZY SOUTH SOUTHEAST WINDS
IN CONTROL. FEW TO SCT LOW CLOUDS MAINLY EAST OF US281/IH69C.
MOSTLY CLEAR SKIES TONIGHT. DEEPER MOISTURE WILL BRING THICKER
CLOUDS ON THURSDAY...BUT STILL LOOKING FOR VFR CONDITIONS. A WEAK
SEA BREEZE WILL BE POSSIBLE.
&&
.PREV DISCUSSION... /ISSUED 652 AM CDT WED SEP 9 2015/
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
AVIATION...LIGHT SOUTHEAST WINDS WITH A FEW PASSING CLOUDS
PREVAIL OVER DEEP SOUTH TEXAS THIS MORNING. VFR CONDITIONS
EXPECTED THROUGH THE NEXT 24 HOURS...EXCEPT A BRIEF PERIOD OF MVFR
CONDITIONS POSSIBLE IN ANY CONVECTION. ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS THE EASTERN PORTIONS
OF THE CWA ALONG AND AHEAD OF THE SEABREEZE FRONT MOVING INLAND
THIS AFTERNOON. LIGHT SOUTHEAST WINDS WILL BECOME MODERATE LATER
THIS MORNING WITH GUSTS AROUND 20 KNOTS IN THE AFTERNOON. WINDS
WILL GRADUALLY WEAKEN THIS EVENING AND OVERNIGHT.
PREV DISCUSSION... /ISSUED 434 AM CDT WED SEP 9 2015/
SHORT TERM /NOW THROUGH THURSDAY/...LATEST WATER VAPOR SATELLITE
IMAGERY SHOWS A 500MB RIDGE CENTERED OVER WEST TEXAS INTO NORTHERN
MEXICO AND A 500MB LOW OVER THE WESTERN GULF OF MEXICO. BROWNSVILLE
RADAR SHOWS VERY ISOLATED ACTIVITY ACROSS THE LOWER TEXAS GULF
WATERS THIS MORNING. THE LATEST HRRR SUGGESTS CONVECTION WILL
INCREASE ACROSS THE GULF WATERS LATER THIS MORNING. BRO SOUNDING
FROM TUESDAY EVENING INDICATES PRECIPITABLE WATER VALUES OF 2.02
INCHES. MOSTLY CLEAR SKIES AND LIGHT WINDS PREVAIL ACROSS DEEP SOUTH
TEXAS EARLY THIS MORNING. NOTE...THE SURFACE OBSERVATION FROM
EDINBURG IS NOT REPRESENTATIVE TO CURRENT WEATHER CONDITIONS.
THE COMBINATION OF THE 500MB LOW ACROSS THE WESTERN GULF OF MEXICO
AND A FRONT MOVING SOUTH OVER CENTRAL TEXAS WILL ALLOW LOW TO MID
LEVEL MOISTURE TO INCREASE ACROSS DEEP SOUTH TEXAS THROUGH THE
FORECAST PERIOD. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
WILL DEVELOP ACROSS THE EASTERN PORTIONS OF THE CWA ALONG AND AHEAD
OF THE SEABREEZE FRONT MOVING INLAND THIS AFTERNOON. THE LATEST
HRRR/GFS AND ECMWF SUGGEST AN ACTIVE SEA BREEZE TODAY WHILE THE MET
REMAINS GENERALLY DRY. WILL LEAN TOWARDS THE WETTER MAV/ECMWF MOS
POPS FOR TODAY.
DEEPER MOISTURE SHOULD SUPPORT MORE ACTIVITY ACROSS THE AREA ON
THURSDAY...ESPECIALLY ACROSS THE COASTAL WATERS AND THE RANCHLANDS.
WILL BLEND TOWARDS THE WETTER NAM/ECMWF FOR POPS AREA WIDE FOR
THURSDAY.
ANY OF THE HEAVIER OR SLOWER-MOVING SHOWERS AND THUNDERSTORMS TODAY
AND THURSDAY WILL HAVE THE POTENTIAL TO PRODUCE LOCALLY HEAVY
RAINFALL WITH NUISANCE FLOODING ON ROADS AND IN LOW-LYING
AREAS...ESPECIALLY THOSE WITH A HISTORY OF FLOODING.
HIGH TEMPERATURES TODAY WILL RANGE FROM THE LOWER 90S NEAR THE COAST
TO AROUND 100 ACROSS THE UPPER VALLEY. HIGH TEMPERATURES WILL BE A
FEW DEGREES LOWER ON THURSDAY DUE TO THE INCREASE IN CLOUDS AND RAIN
CHANCES. LOW TEMPERATURES TONIGHT WILL GENERALLY BE IN THE UPPER 70S
TO AROUND 80.
LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...RATHER BUSY LONG
TERM PORTION OF THE FORECAST ANTICIPATED. DEEP TROPICAL MOISTURE
(PRECIPITABLE WATER VALUES IN EXCESS OF 2 INCHES) WILL COMBINE
WITH THE FRIDAY NIGHT PASSAGE OF A WEAK COLD FRONT...AND THE
SUBSEQUENT DEVELOPMENT AND PERSISTENCE OF AN INVERTED SURFACE
TROUGH OF LOW PRESSURE ALONG THE LOWER TEXAS COAST AFTERWARDS.
WITH PERSISTENT 500 MB TROUGHINESS ALONG THE TEXAS COASTLINE IN
ASSOCIATION WITH A CLOSED 500 MB LOW PRESSURE SYSTEM OVER THE
GREAT LAKES REGION...DEEP SOUTH TEXAS AND THE RIO GRANDE VALLEY
CAN EXPECT SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS FOR
MUCH OF THE FORECAST PERIOD...WITH THE HIGHEST RAIN CHANCES FROM
FRIDAY THROUGH SATURDAY...WHEN LOCALLY HEAVY RAINFALL HAS ALSO
BEEN INCLUDED IN THE FORECAST. THE MOST INTERESTING ASPECT OF THE
LONG TERM FORECAST PERIOD IS THE GFS` INDICATION THAT A WEAK
CLOSED AREA OF LOW PRESSURE WILL FORM OVER THE WESTERN GULF OF
MEXICO AND MOVE INLAND OVER THE BRO CWFA TOWARDS THE END OF THE
FORECAST PERIOD. ANY CLOSED AREA OF LOW PRESSURE...SHOULD IT
FORM...WOULD HAVE THE ABILITY TO RADICALLY CHANGE PRECIPITATION
AND WIND VALUES ON MONDAY AND TUESDAY...AND THIS WILL NEED TO BE
MONITORED BY SUCCESSIVE SHIFTS THROUGH THE NEXT FEW DAYS.
MARINE...NOW THROUGH THURSDAY...BUOY DATA AND OBSERVATION PLATFORMS
ALONG THE LOWER TEXAS COAST THIS MORNING INDICATE SOUTH WINDS BETWEEN
8 TO 13 KNOTS WITH SEA HEIGHTS NEAR 3 FEET ON THE GULF WATERS. A
WEAK PRESSURE GRADIENT OVER THE WESTERN GULF OF MEXICO WILL
MAINTAIN LIGHT TO MODERATE SOUTHEAST TO SOUTH WINDS AND LOW TO
MODERATE SEAS. HOWEVER...SMALL CRAFT WILL NEED TO EXERCISE CAUTION
ON THE LAGUNA MADRE THIS AFTERNOON DUE TO A SLIGHTLY STRONGER
WINDS.
THURSDAY NIGHT THROUGH TUESDAY...GENERALLY LIGHT TO MODERATE WINDS
AND LOW TO MODERATE SEAS ARE EXPECTED THROUGH THE PERIOD AS WEAK
LOW PRESSURE PERSISTS OVER THE WESTERN GULF OF MEXICO AND A COLD
FRONT INTRUDES INTO THE LOWER TEXAS COASTAL WATERS. WEAK CLOSED
LOW PRESSURE MAY DEVELOP ALONG THE LOWER TEXAS COAST TOWARDS THE
END OF THE FORECAST PERIOD PER ONE WEATHER FORECAST MODEL...BUT
THE STRONGER WINDS AND HIGHER SEAS INDICATED IN ASSOCIATION WITH
THE LOW PRESSURE DEVELOPMENT HAVE NOT BEEN INCLUDED IN THE
FORECAST AT THIS TIME.
BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
54/64
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
208 PM CDT WED SEP 9 2015
.SHORT TERM...(TONIGHT THROUGH THURSDAY NIGHT)
ISSUED AT 208 PM CDT WED SEP 9 2015
BIG PICTURE WATER VAPOR IMAGERY/RAP ANALYSIS SHOWING A CLOSED UPPER
LOW OVER WESTERN ONTARIO WITH A BROAD TROUGH OVER THE
NORTHER/CENTRAL CONUS. AN EMBEDDED MID-LEVEL SHORTWAVE TROUGH WAS
PUSHING INTO MN/DAKOTAS. RADAR MOSAIC SHOWING SCATTERED BAND OF
SHOWERS AND THUNDERSTORMS AHEAD OF THIS WAVE EXTENDING FROM
NORTHWEST WI/EAST CENTRAL MN TO SOUTH CENTRAL MN...MOVING EAST AT 35-
40KT. OTHERWISE...TEMPERATURES AS OF 2 PM RANGED FROM NEAR 70 ACROSS
NORTH CENTRAL WI...TO THE 75-80 DEGREE RANGE ALONG AND SOUTH OF I-90.
FOR THIS EVENING OVERNIGHT...WILL BE WATCHING THE WAVE CONTINUE
MOVING EAST ACROSS OUR AREA. RAP DEPICTING INCREASING 850-700MB
MOISTURE TRANSPORT ALONG WITH INCREASING MUCAPE...HIGHER 500-1000
J/KG SOUTH OF I-90. THEREFORE CARRIED SHRA/TS ALONG AND SOUTH OF I-
90 WITH ISOLATED THUNDER NORTH. MOST MESO MODELS DEPICTING SCATTERED
NATURE TO THIS CONVECTION...SO MAINTAINED 30-50 POPS FOR NOW.
ANOTHER STRONGER MID-LEVEL WAVE/DECENT 500-300MB PV-ADVECTION PUSHES
IN ACROSS THE NORTHERN PLAINS INTO THE UPPER MISSISSIPPI RIVER
VALLEY BY TOMORROW MORNING AND IS EXPECTED TO REINFORCE
SHOWER/THUNDER CHANCES ACROSS THE AREA. WITH EXPECTED SCATTERED
CONVECTION AND CLOUD COVER...WILL SEE COOLER TEMPERATURES WITH HIGHS
ACROSS NORTH CENTRAL WI ONLY IN THE 65-70 DEGREE RANGE AND LOW-MID
70S SOUTH OF I-90.
LOOKS LIKE SHOWER/ISOLATED THUNDER CHANCES PUSH OUT OF THE AREA BY
LATER THURSDAY EVENING WITH CLEARING SKIES THROUGH THE OVERNIGHT
HOURS. WITH DEEPENING MID/UPPER LEVEL TROUGH OVERHEAD AND RATHER
COLD 850MB TEMPS DROPPING INTO THE 1-5C RANGE...WILL SEE OVERNIGHT
LOWS DIP INTO THE 40S MOST LOCATIONS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 208 PM CDT WED SEP 9 2015
FOR FRIDAY THROUGH SATURDAY NIGHT...
ANOTHER EMBEDDED SHORTWAVE TROUGH COMES DOWN ACROSS THE AREA ON
FRIDAY. STEEP LOW TO MID-LEVEL LAPSE RATES EXPECTED TO GENERATE
QUITE A BIT OF CUMULUS AND SCATTERED SHOWERS...MAINLY ALONG AND EAST
OF THE MISSISSIPPI RIVER. OTHERWISE...A RATHER CHILLY AUTUMN-LIKE
DAY ON TAP AS HIGHS ONLY TOP OFF IN THE UPPER 50S TO THE MIDDLE 60S.
CHILLY DAY FRIDAY AND CLEARING SKIES FRIDAY NIGHT AS SURFACE HIGHS
SETTLES IN WILL SET THE STAGE FOR COLD TEMPERATURES FRIDAY NIGHT
WITH LOWS DIPPING INTO TO THE UPPER 30S/AROUND 40 ACROSS NORTH
CENTRAL WI...TO THE LOWER/MIDDLE 40S ELSEWHERE.
MODELS SHOW THE MID-LEVEL TROUGH PUSHING INTO THE EASTERN GREAT
LAKES/OHIO RIVER VALLEY SATURDAY AS MID-LEVEL RIDGE BUILD INTO OUR
REGION. THIS WILL PROVIDE DRY AND SLIGHTLY WARMER //BUT STILL WELL
BELOW NORMAL// TEMPERATURES IN THE LOW-MID 60S UNDER MOSTLY SUNNY
SKIES.
PLAN ON ANOTHER CLEAR AND COLD SATURDAY NIGHT WITH SURFACE HIGH
OVERHEAD. LOOKS TO BE AN IDEAL RIVER VALLEY/BOG AREA FOG NIGHT WITH
OVERNIGHT LOWS DIPPING INTO THE 40S ONCE AGAIN. DID NOT INCLUDE IN
THE WEATHER GRIDS FOR NOW AS EXACT RIDGE LOCATION COULD CHANGE A
BIT...BUT SOMETHING TO KEEP AN EYE ON NONETHELESS.
FOR SUNDAY THROUGH WEDNESDAY...DAYS 4 TO 7...
GFS AND ECMWF IN AGREEMENT ON A WARMING TREND FOR THIS PERIOD AS LOW
PRESSURE LIFT ACROSS THE NORTHERN PLAINS INTO CANADA. THIS PUTS US
IN WARM SECTOR WITH BROAD-SCALE LIFT ACROSS OUR AREA FOR A CHANCE OF
SHOWERS AND THUNDERSTORMS MAINLY IN THE TUESDAY NIGHT THROUGH
WEDNESDAY TIME FRAME. LOOKS LIKE HIGHS ON SUNDAY IN THE 65-70 DEGREE
RANGE...WARMING BACK INTO THE 70S...OR NEAR SEASONAL NORMALS...BY
WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1230 PM CDT WED SEP 9 2015
MAIN TAF CONCERNS ARE SHOWERS/THUNDERSTORM CHANCES AT BOTH RST/LSE
TAF SITES THIS EVENING INTO THURSDAY MORNING. A WEAK UPPER LEVEL
DISTURBANCE OVER WESTERN MINNESOTA WILL MOVE OVER THE RST/LSE TAF
SITES LATE THIS AFTERNOON INTO THURSDAY MORNING. THE LATEST 09.12Z
RAP/NAM SUGGEST WEAK MOISTURE CONVERGENCE AND VERTICAL MOTION IN
ASSOCIATION WITH THE UPPER LEVEL DISTURBANCE. DRY AIR ALOFT AND NEAR
THE SURFACE WILL ALLOW CLOUD HEIGHTS TO REMAIN ABOVE THE MVFR
CONDITIONS FOR THE MAJORITY OF THE TAF PERIOD. WITH THE FAST
PROGRESSION OF THE UPPER LEVEL DISTURBANCE...CEILING HEIGHTS MAY
BRIEFLY LOWER TO MVFR BETWEEN THE 03Z-10Z THURSDAY TIME FRAME.
EXPECT VFR CONDITIONS TO PREVAIL AT BOTH TAF SITES THROUGH TAF
PERIOD. THUNDERSTORM PROBABILITIES REMAIN VERY LOW AT TAF SITES...AS
THE 09.12Z NAM/RAP SUGGEST LIMITED ELEVATED INSTABILITY WITH THE
UPPER LEVEL DISTURBANCE. WILL KEEP MENTION OF THUNDER OUT OF TAF
PERIOD...DUE TO THIS LIMITED INSTABILITY AND ISOLATED TO SCATTERED
COVERAGE OF CONVECTION.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...DTJ